JP2002256833A - Direct drive type valve mechanism of internal combustion engine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To miniaturize a valve mechanism equipped with a trigger mechanism, and consequently to miniaturize an internal combustion engine. SOLUTION: In an direct drive type valve mechanism equipped with a cam die 22 having a cam part 30a provided on a cam shaft 7 movable in the rotational shaft line and provided with a plurality of cams 31a, 32a, a lifter 24a, and a change-over means having a operation member 47 selectively changing-over a cam moving the lifter 24a and the cam die 22 to the rotational shaft axis line to slide with the lifter 24a, a trigger mechanism T setting the change-over starting timing of the change-over means is arranged below the cam shaft 7. The trigger mechanism T is prevented from the movement of the operation by coming in contact with the operation member 47 by staying in a moving passage of the operation member 47 and sets the change-over starting timing just after closing the engine valve.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a cam piece having a cam portion provided with a plurality of cams having different cam profiles and moving the cam piece in the direction of the rotation axis of a cam shaft. The present invention relates to a direct-acting valve train for an internal combustion engine having a switching means for selectively switching a cam that slides on a lifter disposed between the engine valve and the engine valve.

[0002]

2. Description of the Related Art Conventionally, in order to change a valve operating characteristic of an intake valve or an exhaust valve of an internal combustion engine, a valve operating device provided with switching means for selectively switching a plurality of cams having different cam profiles has been proposed. Japanese Patent Application Laid-Open No. 61-2018 discloses a device provided with a trigger lever for setting the switching operation start timing.
No. 04 discloses this. This valve gear is provided on a cam shaft, and a cam cylinder (cam piece) provided with a middle / low speed cam and a high speed cam adjacent to each other with different cam profiles.
A rocker arm abutting on one of the two cams,
It has a switching mechanism (switching means) for moving the cam cylinder in the direction of the rotation axis of the cam shaft, and a trigger lever swingably supported by a trigger lever support shaft arranged parallel to the cam shaft. One end of the trigger lever is engaged with a trigger cam formed on the camshaft, and the other end is adapted to be fitted into a groove of a piston of the switching mechanism. When the engagement with the groove is released, the switching operation start timing is set.

[0003]

By the way, in the conventional valve operating device, the trigger lever supporting shaft and the trigger lever are disposed above the cam shaft, so that the valve operating device becomes large, and the valve operating device is housed. There is a problem that the valve train and the internal combustion engine become large. In addition, in the conventional valve gear, since the intake valve is operated by a cam that slides on the rocker arm, a rocker arm support shaft is also arranged around the cam shaft in addition to the trigger lever support shaft. Therefore, it is necessary to secure a swing range of the trigger lever and the rocker arm respectively supported, and in this respect, the valve train tends to be large. Further, in the conventional valve gear, a trigger cam is provided on the cam shaft along with the cam cylinder in order to operate the trigger lever. Therefore, the valve gear having the trigger lever is large in the rotation axis direction of the cam shaft. In addition, it is necessary to provide a trigger cam which is a member for operating the trigger lever, and there has been a problem that the operation mechanism is complicated.

[0004] The present invention has been made in view of such circumstances, and the invention described in claims 1 to 5 is:
It is an object of the present invention to reduce the size of a valve train provided with a trigger mechanism, and further reduce the size of an internal combustion engine. And Claim 3
The invention described above further aims at simplifying the operation mechanism for operating the trigger mechanism, and the invention described in claim 5 further aims at reducing the number of parts and the number of assembly steps.

[0005]

According to the first aspect of the present invention, a cam shaft rotatably supported by a cylinder head is provided so as to be movable in the direction of the rotation axis thereof and to rotate together with the cam shaft. A cam piece having a cam portion provided with a plurality of cams having different cam profiles adjacent to each other in the rotation axis direction, and an engine valve for controlling intake and exhaust of the internal combustion engine with the cam portion. And a lifter that is disposed between the lifter and the lifter and that is vertically movably held by the lifter holding member, and the cam that moves in the rotation axis direction to selectively switch the cam that slides on the lifter of the cam portion. Switching means, wherein the engine valve is operated in accordance with a cam profile of the cam which slides on the lifter, wherein the switching means closes the engine valve. Trigger mechanism for setting the switching operation start timing at is a direct acting valve gear of an internal combustion engine is disposed below the cam shaft.

According to the first aspect of the invention, the following effects can be obtained. That is, the engine valve is held by the lifter holding member movably up and down and is operated via the lifter with which the cam slides, so that the upward dimension of the valve gear is reduced and the cam piece is rotated. Since the trigger mechanism for setting the switching operation start timing of the switching means for switching the operating characteristics of the engine valve by moving in the axial direction is disposed below the camshaft, that is, at a position closer to the cylinder block, the trigger mechanism is disposed below the camshaft. By using the space, the valve train with the trigger mechanism is downsized, and the valve train and the internal combustion engine are downsized.

According to a second aspect of the present invention, in the direct-acting valve train for an internal combustion engine according to the first aspect, the trigger mechanism is disposed between the camshaft and the lifter.

According to the second aspect of the present invention, the following effect is achieved in addition to the effect of the first aspect of the present invention. That is, since the trigger mechanism can be arranged using the space between the camshaft and the lifter, the valve train can be further downsized.

According to a third aspect of the present invention, in the direct-acting type valve train of the internal combustion engine according to the first or second aspect, the trigger mechanism overlaps the lifter as viewed from a direction of the vertical movement of the lifter. And is operated in conjunction with the movement of the lifter.

According to the third aspect of the invention, the following effect is obtained in addition to the effects of the first or second aspect of the invention. That is, since the trigger mechanism is operated in conjunction with the lifter moved by the cam that slides,
Since it is not necessary to newly provide a member for operating the trigger mechanism, the operating mechanism for operating the trigger mechanism is simplified, and the valve train provided with the trigger mechanism can be downsized. Since the mechanism is arranged so as to overlap the lifter when viewed from the cylinder axis direction, the valve train provided with the trigger mechanism can be downsized even in the direction of the rotation axis of the camshaft.

According to a fourth aspect of the present invention, in the direct-acting type valve train for an internal combustion engine according to any one of the first to third aspects, the cam portion is formed in the cam piece in the direction of the rotation axis. A first cam portion and a second cam portion provided in series, wherein the engine valve includes a first engine valve and a second engine valve provided for the same cylinder;
A trigger mechanism including a first lifter disposed between the first engine valve and the first cam portion, and a second lifter disposed between the second engine valve and the second cam portion; Is
It is arranged between the first lifter and the second lifter in the rotation axis direction.

According to the invention described in claim 4, in addition to the effects of the invention described in the cited claims, the following effects are exerted. That is, when the valve gear includes at least two engine valves that are operated by a common cam piece for one cylinder, and includes at least two lifters corresponding to the engine valves, the trigger mechanism is configured to rotate the rotation axis. In this direction, since the lifter is disposed between the two lifters, the first and second lifters, the valve train having the trigger mechanism can be downsized in the rotation axis direction.

According to a fifth aspect of the present invention, there is provided a direct-acting valve train for an internal combustion engine according to any one of the first to fourth aspects, wherein the lifter holding member is connected to a cylinder head of the internal combustion engine. The trigger mechanism is formed of a separate member, and is fixed to the lifter holding member by a fixing member that fixes the lifter holding member to the cylinder head.

According to the fifth aspect of the present invention, the following effects can be obtained in addition to the effects of the cited invention. That is, since the trigger mechanism is fixed to the lifter holding member using the fixing member for fixing the lifter holding member to the cylinder head, the number of components and the number of assembling steps can be reduced.

[0015]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to FIGS. FIGS. 1 to 15 show a first embodiment of the present invention. An internal combustion engine E to which a direct-acting valve train according to the present invention is applied is equipped with a D mounted on a vehicle.
This is an OHC type in-line 4-cylinder 4-cycle internal combustion engine.
As shown in the figure, the internal combustion engine E has four cylinders 1
The cylinder head 3 is assembled on the upper surface of the cylinder block 2 (one of which is shown in FIG. 1), and the head cover 4 is assembled on the upper surface of the cylinder head 3. In this specification, "up and down"
Means “up and down” when the internal combustion engine E is viewed in the state shown in FIG. 1 for convenience.

A piston 5 reciprocally fitted in the bore of each cylinder 1 drives a crankshaft (not shown) via a connecting rod 6. A plurality of intake camshafts 7 and exhaust camshafts 8, which are driven to rotate at half the number of rotations in synchronization with the crankshaft, are arranged in parallel with the crankshaft and fixed to the cylinder head 3 by bolts. Intake cam holder 9 and a plurality of exhaust cam holders 10 (FIG. 1)
In FIG. 1, one of them is shown). The cam holders 9, 10 are arranged at both ends in the cylinder arrangement direction and between two adjacent cylinders 1. Each of the cam holders 9, 10 is divided into upper and lower divided upper cam holders 9U, 10U and lower cam holders 9U, 10U. Become.

In the cylinder head 3, for each cylinder 1,
A combustion chamber 11 is formed between the piston 5 and an intake port 12 having a pair of intake ports and an exhaust port 13 having a pair of exhaust ports. A pair of intake valves 14 that open and close the respective ports to control the intake of the internal combustion engine E, and a pair of intake valves 14 that open and close the respective exhaust ports to control the exhaust of the internal combustion engine E. An exhaust valve 15 is slidably provided on the valve guides 16 and 17. Then, each intake valve 14 and each exhaust valve 15 are urged in a direction to close the intake port and the exhaust port, respectively, by the spring force of the valve springs 18, 19 whose upper ends are supported by spring receivers 26, 27. Each cylinder head 3 has a combustion chamber 11
An ignition plug 20 is provided.

Between the cylinder head 3 and the head cover 4
The intake valve 14 and the exhaust valve 15 are provided in the valve operating chamber 21 formed in
A direct-acting valve train for opening and closing is housed. This valve
The device is an intake-side valve train V_INAnd exhaust side valve gear V_EXAnd
And the intake-side valve train V_INAre the camshaft 7, the cam piece 22,
Lifter 24 and the direction of its rotation axis L1 on camshaft 7
(Hereinafter referred to as “rotation axis direction A1”)
Hydraulic intake-side drive mechanism M as switching means for switching_INTo
Equipped, exhaust side valve train V_EXAre the camshaft 8, cam piece 23,
Put the lid 25 and the cam piece 23 on the camshaft 8 in the rotational axis direction A1.
Hydraulic exhaust drive mechanism as switching means
M_EXIs provided. And the intake side valve train V _INAnd exhaust
Side valve device V_EXHave basically the same configuration.
Therefore, in the following description, the intake-side valve train V_INAround
Will be described.

Referring also to FIG. 2, the camshaft 7 includes
For each cylinder 1, a cam piece 22 having a shaft hole through which the camshaft 7 penetrates is slidable with respect to the camshaft 7 in the rotation axis direction A1 and is movable together with the camshaft 7 in the rotation direction. In order to rotate, three concave grooves 26 provided on the inner peripheral surface of the cam piece 22 over the entire length in the rotation axis direction A1, and the outer peripheral surface of the cam shaft 7, the cam piece 22 in the rotation axis direction A1. Are attached by spline connection with three protruding ridges 27 provided over the range of movement.

The cam piece 22 is provided with a first cam portion 30a and a second cam portion 30b in series and spaced from each other in the rotation axis direction A1, and the first and second cam portions 30a and 30b are respectively provided. Low-speed cams 31a and 31b and high-speed cam 32 with different cam profiles
a and 32b are integrally provided adjacent to each other in the rotation axis direction A1. That is, each of the low-speed cams 31a and 31b has a relatively small protrusion amount in the radial direction of the camshaft 7 (hereinafter, simply referred to as "radial direction") and has a nose portion 31a having a predetermined operating angle in the circumferential direction.
The high-speed cams 32a and 32b each have a cam profile composed of base circle portions 31a2 and 31b2. Nose parts 32a1, 32b1 having a larger operating angle than that of low-speed cams 31a, 31b, and a low-speed cam
The cam profile includes a base circular portion 32a2, 32b2 having the same radial protrusion amount as the base circular portion 31a2, 31b2 of the base 31a, 31b.

Further, the cam piece 22 has a cylindrical portion 33 between the first cam portion 30a and the second cam portion 30b in the rotation axis direction A1.
The cylindrical portion 33 is provided with a pair of circular first outer circumferences 35 and a second engagement portion 35 having a pair of circular outer circumferences forming an annular guide groove 34 having an outer peripheral surface as a bottom surface. A joint 36 is provided. The outer diameters of the first and second engaging portions 35 and 36 are equal to the base circular portions 31a2 and 31a2 of the low-speed cams 31a and 31b and the high-speed cams 32a and 32b.
In a state where 31b2, 32a2, and 32b2 are in sliding contact with the lifter 24, the size is set so as not to contact the lifter 24.

A first lifter 24a is disposed below the cam piece 22 between the first cam portion 30a and the first intake valve 14a for each cylinder 1, and the second cam portion 30b and the second Intake valve
The second lifter 24b is arranged between the second lifter 24b and the second lifter 24b. The cylinder head 3 has four holder portions 37 corresponding to the respective cylinders 1, and the adjacent holder portions 37 are connected to each other by connecting portions 38.
(See FIG. 6), the connected lifter holders are fixed. Referring also to FIG. 6, each of the holder portions 37 of the lifter holder constituting the lifter holding member has three boss portions 37.
The first and second lifters 24a and 24b, which are fixed to the cylinder head 3 by bolts B as fixing members inserted into the through holes 37b formed in the A pair of first guide holes 39a and second guide holes 39b provided coaxially with the second lifters 24a and 24b respectively reciprocate in the center axis direction A2 of the first and second lifters 24a and 24b. It is fitted so that it can slide freely. Therefore, the center axis direction A2 is also the direction of the vertical movement of the first and second lifters 24a and 24b.

Each of the first and second lifters 24a and 24b is a cylinder having an open lower end and a top wall at the upper end, including a center axis L2 (see FIG. 1), and orthogonal to the rotation axis L1 of the cam shaft 7. Rotational axis direction A1 from the top wall so as to be plane symmetric with respect to the plane
It has a pair of cutouts 40a1, 40a2, 40b1, 40b2 formed by cutting out a part of the side wall on both sides (see FIG. 2). The remaining portion of the top wall extends in the diametrical direction of the cylinder, and the low speed cams 31a, 31b and the high speed cams 32a, 3a
Bridge-shaped slipper portions 42a and 42b with which 2b slides are formed. The upper surfaces of the slipper portions 42a, 42b with which the low-speed cams 31a, 31b and the high-speed cams 32a, 32b are in slidable contact form an arc that is convex toward the first and second cam portions 30a, 30b when viewed from the rotation axis direction A1. Has become.

Referring also to FIG. 7, the slipper section 42
The outer surfaces of the side walls of the first and second lifters 24a and 24b connected to the first and second lifters a and b have a semicircular cross section extending in the central axis direction A2 and end walls at the upper and lower ends in the central axis direction A2. Grooves 24a1 and 24b1 are formed, while, on the peripheral wall surfaces of the first and second guide holes 39a and 39b, at positions radially opposed to the insertion grooves 24a1 and 24b1, similarly to the insertion grooves 24a1 and 24b1. Engagement grooves 39a1 and 39b1 each having a semicircular cross section and having an open upper end in the central axis direction A2 and having an end wall surface at the lower end are formed. The insertion grooves 24a1 and 24b1 are inserted into the insertion grooves 24a1 and 24b1.
A pin 43 for locking having a length slightly shorter than the length of the first and second lifters 24a1 and 24b1 is inserted in the center axis direction A2 of the insertion grooves 24a1 and 24b1. That is, the pin 43 prevents rotation of the first and second lifters 24a and 24b with respect to the holder portion 37 by being disposed over the locking grooves 39a1 and 39b1 having a length that allows vertical movement. You.

Therefore, when the intake side drive mechanism M _IN moves the cam piece 22 in the rotation axis direction A1, the first and second
The low-speed cams 31a, 31b and the high-speed cam 32 of the cam portions 30a, 30b
a, 32b are selectively slid on the slipper portions 42a, 42b, and are pressed by the cams 31a, 31b, 32a, 32b which are in slidable contact.
Via the second lifters 24a, 24b, the first and second intake valves 14a, 1
4b are activated with respective cam profiles to open and close the inlet.

Referring to FIGS. 3 and 4, the intake drive mechanism M _IN provided for each cylinder 1 is located on both sides of the cam piece 22 in the rotation axis direction A1, and the adjacent upper cam holders. The first cylinder portion 45a and the second cylinder portion 45a each having a cylindrical concave portion provided in the boss portions facing each other of 9U.
A double-acting drive piston 46 having a cylinder portion 45b and a first piston portion 46a and a second piston portion 46b slidably fitted to the first and second cylinder portions 45a, 45b, respectively.
And a connecting portion 46 connecting the first and second piston portions 46a and 46b.
c, together with the connecting portion 46c, the first and second piston portions 46
an arm 47 which is an operation member integrally formed with the first and second a and b and extends from the connecting portion 46c toward the guide groove 34 of the cam piece 22;
A first hydraulic chamber 48a formed between the cylinder part 45a and the first piston part 46a, a second cylinder part 45b and a second piston part
And a second hydraulic chamber 48b formed between the second hydraulic chamber 48b and the second hydraulic chamber 48b.

The driving piston 46 reciprocates in the direction A1 of the rotation axis upon receiving a driving force corresponding to the hydraulic pressure of the working oil supplied to the first and second hydraulic chambers 48a and 48b. This driving force is
Base circle portion of low-speed cams 31a and 31b and high-speed cams 32a and 32b
31a2, 31b2, 32a2, 32b2 are in sliding contact with both slipper portions 42a, 42b, ie, when the first and second intake valves 14
When the valves 14a and 14b are closed, the low-speed cams 31a and 31b and the high-speed cams 32a and 32b
a slightly larger than the frictional force generated between the low-speed cams 31a and 31b and the high-speed cams 32a and 32b.
31a1, 31b1, 32a1, 32b1 are in sliding contact with both slipper portions 42a, 42b, ie, when the first and second intake valves 14
When the valves a and 14b are opened, the low speed cams 31a and 31b and the high speed cams 32a and 32b
a, it is set to less frictional force generated between the 42b, the low-speed cam 31a by the intake-side drive mechanism M _IN, 31b and high speed cams
Switching between 32a and 32b is substantially the first and second intake valves.
This is performed when the valves 14a and 14b are closed.

The arm 47 disposed between the first cam portion 30a and the second cam portion 30b in the rotation axis direction A1 has a cylindrical portion.
Bifurcated fork-shaped first contact part surrounding 33 in an arc shape
47a and a second contact portion 47b, and the first and second contact portions 47
The a and 47b abut on the first and second engagement portions 35 and 36 of the cam piece 22 in the rotation axis direction A1 while being inserted into the guide groove 34. The distance d1 between the first engagement portion 35 and the second engagement portion 36 in the rotation axis direction A1 is the rotation axis direction A1 of the first and second contact portions 47a and 47b.
In the state where the first and second contact portions 47a and 47b are in contact with one of the first and second engagement portions 35 and 36, the first and second contact portions 47a, 47b and the first and second engagement portions 35,
A gap G1 having a predetermined width in the rotation axis direction A1 is formed between one of them and the other. Further, the first and second contact portions 47
At least a first abutting portion 47a of the first and second abutting portions 47a, 47b that comes into contact with a trigger piece 52, which will be described later, radially protrudes from the first and second engaging portions 35, 36. Is set.

Next, the hydraulic system of the intake side drive mechanism M _IN will be described. The cylinder block 2, the cylinder head 3 and the cylinder head 3 are disposed in the discharge path of an oil pump provided in the internal combustion engine E and driven by the power of the crankshaft. A working oil passage (not shown) provided in the cam holder 9 and having an opening 49a communicates with the first hydraulic chamber 48a, and a first control valve (not shown) provided in the working oil passage allows a first control valve (not shown) to perform the first operation. The operating oil pressure of the hydraulic chamber 48a is controlled to a high oil pressure or a low oil pressure. Similarly,
A second control valve (not shown) provided in a second hydraulic oil passage (not shown) having an opening 49b in the second hydraulic chamber 48b raises the hydraulic pressure of the second hydraulic chamber 48b to a high hydraulic pressure or a low hydraulic pressure. Is controlled.

The operation of the first and second control valves is controlled by a control device (not shown) to which a signal detected by a rotation speed sensor, which is an engine operation state sensor (not shown), is input. That is, the first control valve controls the hydraulic oil pressure so that the hydraulic oil in the first hydraulic chamber 48a is low in a low-speed rotation range equal to or lower than a predetermined rotation speed of the internal combustion engine E, and the second control valve The valve is the second hydraulic chamber 48b
The driving piston 46 occupies the low-speed position shown in FIG. Further, when the rotation speed of the internal combustion engine E is in a high-speed rotation range exceeding the predetermined rotation speed, the first control valve controls the hydraulic pressure of the working oil so that the first hydraulic chamber 48a has a high hydraulic pressure,
The second control valve controls the hydraulic pressure of the working oil so that the second hydraulic chamber 48b has a low hydraulic pressure, and the drive piston 46 occupies the high-speed position shown in FIG.

The cam holder 9 located between the adjacent cylinders 1 has a plane passing through the center point of the cam holder 9 in the rotation axis direction A1 and orthogonal to the rotation axis L1 as shown in FIGS. The second hydraulic chamber 48b belonging to the cylinder 1 on the right side and the second hydraulic chamber 48b belonging to the cylinder 1 on the left side of the upper cam holder 9U are arranged so as to be plane-symmetrical. The hydraulic oil passage is shared by 48b. The same applies to the other cam holders 9 located between the adjacent cylinders 1 and the components of the valve train V belonging to the cylinders 1.

The hydraulic oil system of the exhaust-side drive mechanism M _EX of the exhaust-side valve train V _EX is also supplied with controlled hydraulic oil in the same manner as the above-described intake-side drive mechanism M _IN. ing.

Next, referring to FIGS. 5 to 7, the driving piston 46 moves the cam piece 22 via the arm 47 so that the low speed cams 31a and 31b and the high speed cam 32a slidingly contact the slipper portions 42a and 42b. , 32b will be described. As shown in FIGS. 5 and 6, the trigger mechanism T includes a trigger bracket 50 fixed to the holder 37 by two bolts B for fixing the holder 37 to the cylinder head 3 near the center axis of the cylinder 1.
A trigger base 51 swingably supported by the trigger bracket 50, a trigger piece 52 swingably supported by the trigger base 51, and a trigger piece 50 between the trigger bracket 50 and the trigger piece 52. A trigger spring 53 comprising a compression coil spring provided, a trigger bracket 50, a trigger base
Each of the trigger piece 51 and the trigger piece 52 is formed of a flat plate material along the rotation axis direction A1.

The trigger bracket 50 is formed with a pair of engagement holes 50a equidistant from a plane including the central axis L2 of the first and second lifters 24a and 24b, and a rotation axis between the two engagement holes 50a. direction
A spring receiving portion 50b that protrudes upward and supports one end of the trigger spring 53 is provided at the center of A1.

The Y-shaped trigger base 51 has a rectangular support portion 51a having a long side in a direction perpendicular to the rotation axis direction A1 on a plane perpendicular to the center axis direction A2, and a support portion 51a. It has a pair of base ends 51b that are branched and bent in the central axis direction A2. Both base end portions 51b are inserted into both engagement holes 50a from below the trigger bracket 50, and are brought into contact with the upper surface of the trigger bracket 50 so that the trigger bracket
By engaging the trigger base 51 with the trigger bracket 50, the trigger base 51 is moved in the center axis direction
2, the supporting portion 51a is disposed between the first lifter 24a and the second lifter 24b in the rotation axis direction A1, as shown in FIG. The width of the support portion 51a in the rotation axis direction A1 is equal to the width of the first and second cam portions 3.
Outside the rotation path of the first and second lifters 0a and 30b, a portion of both side edges of the support portion 51a in the rotation axis direction A1 is part of the first and second lifters.
The first side wall upper surface 24a2 and the second side wall upper surface 24b2, which are in close contact with each other in the rotation axis direction A1 of the first and second side walls 24a and 24b, are in contact with each other.
It is set so as to constitute the contact part 51c and the second contact part 51d. Further, an insertion groove 51e (FIG. 5) through which a spring receiving portion 52a of a trigger piece 52 described later is inserted is provided on the base end 51b side of the support portion 51a.
On the both sides in the rotation axis direction A1 of the insertion groove 51e, the contact portions 52b of the trigger pieces 52 contact the upper surface of the trigger base 51, and further, the tip of the support portion 51a has a trigger piece. Five
An engagement groove 51f into which the tip of the second 2 fits is formed.

As shown in FIGS. 5 and 7, the trigger piece 52 disposed between the first cam portion 30a and the second cam portion 30b in the rotation axis direction A1 is directed downwardly of the trigger base 51. The trigger spring is formed so as to face the spring receiving portion 50b in the central axis direction A2 and to be located below the spring receiving portion 50b.
A spring receiving portion 52a for supporting the other end of 53, a contact portion 52b, and a first contact portion of the arm 47 located above the trigger base 51.
A regulating portion 52c having a first side surface 52c1 and a second side surface 52c2 in the rotation axis direction A1 with which 47a abuts, and extending in a direction perpendicular to the rotation axis direction A1 on a plane perpendicular to the center axis direction A2.
And a stopper portion 52 formed by bending so as to wrap around the support portion 51a from the tip end portion in a state fitted in the engagement groove 51f.
d. The width of the restricting portion 52c in the rotation axis direction A1 is set to the maximum amount of movement of the driving piston 46, the distance d1 between the first and second engaging portions 35 and 36, and the first distance so that gaps G1 and G3 described later are generated. It is set based on the width W1 of the contact portion 47a.

When the trigger mechanism T is mounted on the holder portion 37, as shown in FIG. 1, the trigger mechanism T is located below the camshaft 7 and in the center axis direction A2. And the first and second lifters 24a, 24b. Then, the base circular portions 31a2, 31b2, 32a2, 32b2 of the low-speed cams 31a, 31b or the high-speed cams 32a, 32b.
Are in sliding contact with the two slipper portions 42a, 42b.
When the valves 14a and 14b are closed, the trigger base 51 is
Trigger spring 53 arranged in the central axis direction A2 between b and 52a
The first and second abutting portions 51c and 51d are supported by the first and second side wall upper surfaces 24a2 and 24d with the base end portion 51b as a fulcrum.
It is urged to abut on b2, and the trigger piece 52 is
The stopper 52d is urged to abut the lower surface of the trigger base 51 with the contact portion 52b abutting on a serving as a fulcrum. In this state, the restricting portion 52c of the trigger piece 52 occupying a position protruding toward the camshaft 7 from the first and second lifters 24a and 24b.
The first and second side surfaces 52c1 and 52c2 are located within the movement path of the first contact portion 47a.

Then, the trigger base 51 and the trigger piece 52
Is that the first and second lifters 24a, 24b are nose portions 31a1, 31b1, 32a1, 32b1 of the low speed cams 31a, 31b and the high speed cams 32a, 32b.
When the first and second intake valves 14a and 14b are lifted (opened), the first and second contact portions 51 of the trigger base 51 are pressed.
In the state where c and 51d are in contact with the first and second side wall upper surfaces 24a2 and 24b2, the first and second lifters 24 swing around the base end 51b as a fulcrum.
When a and 24b move by a predetermined lift amount before moving by the maximum lift amount, the stopper portion 52d comes into contact with the upper surface 37c of the holder portion 37, and the trigger base 51 and the trigger piece 52 move downward therefrom. When the lift amount exceeds the predetermined lift amount, the first and second abutment portions 51c and 51d
It is in a non-contact state with the second side wall upper surfaces 24a2 and 24b2. And
The predetermined lift amount is appropriately set on condition that the regulating portion 52c of the trigger piece 52 occupies a position below the first contact portion 47a of the arm 47 at the predetermined lift amount. Therefore, the trigger base 51 is connected to the first and second lifters 24a, 24a, 2
It functions as a control member that controls the movement of the trigger piece 52 in conjunction with the movement of 4b.

Next, referring to FIGS. 3, 4, 8 and 15, FIG.
In comparison, the operation of the first embodiment configured as described above is described.
Will be described. In the following, the intake side drive mechanism M_INof
The operation will be mainly described._EXBehavior
Basically, the intake side drive mechanism M _INThe operation is the same as that described above.

When the internal combustion engine E is operated and the oil pump is driven, when the rotation speed of the internal combustion engine E is in the low-speed rotation range equal to or lower than the predetermined rotation speed, the intake-side valve train V _IN uses the control device. The first control valve operates so that the hydraulic oil in the first hydraulic chamber 48a becomes low hydraulic pressure, and at the same time, the second control valve changes the hydraulic oil in the second hydraulic chamber 48b to high hydraulic pressure. It works to be. Therefore, the drive piston 46 of the intake-side drive mechanism M _IN occupies the low-speed position shown in FIG.
The low-speed cams 31a, 31b of the first and second cam portions 30a, 30b of the 22
The first and second intake valves 14a and 14b are in sliding contact with the slipper portions 42a and 42b of the first and second lifters 24a and 24b, respectively.
Opening and closing are performed at the opening and closing timings and lift amounts determined by the cam profiles a and 31b. Then, the exhaust side drive mechanism M
_{Since EX} also occupies a low-speed position similarly to the intake-side drive mechanism M _IN , the intake valve 14 and the exhaust valve 15 in each cylinder 1 have a small lift amount, opening / closing timing and short opening time that are suitable for the valve operating characteristics in the low-speed rotation range. It is opened and closed during the valve period.

At this time, as shown in FIG.
The first contact portion 47a and the first and second engagement portions 35 and 36 of the arm 47 located near the lifter 24b, and the high-speed cams 32a and 32b
Are notched portions 40a1, 40a2, despite the fact that they protrude radially beyond the base circular portions 31a2, 31b2 of the low-speed cams 31a, 31b.
Due to the presence of 40b1, there is no contact with the first and second lifters 24a, 24b. Then, the first and second contact portions 47a, 47b
Abuts against the first engagement portion 35 while the first and second abutment portions 47
A gap G1 (see FIG. 3) having a predetermined width in the rotation axis direction A1 is formed between the first engaging portion 36a and the second engaging portion 36, and the first side surface 52c1 of the regulating portion 52c and the first contact portion 47a are formed. Between the gap G1
A gap G2 in the rotation axis direction A1 having a smaller width than the predetermined width is formed. Then, the first and second contact portions 51 of the trigger base 51
c and 51d are in contact with the first and second side wall upper surfaces 24a2 and 24b2. At this time, the second engagement portion 36 occupies a position facing the trigger piece 52 in the center axis direction A2,
The trigger piece 52 is not in contact with the cam piece 22.

When the rotation speed of the internal combustion engine E exceeds the predetermined rotation speed and shifts to a high-speed rotation range, the first control valve is turned on by the command from the control device.
The hydraulic oil in the second hydraulic chamber 48b operates so that the hydraulic oil in the second hydraulic chamber 48b has a low hydraulic pressure. Therefore, the drive piston 46 of the intake side drive mechanism M _IN receives the drive force moving from the low-speed position to the high-speed position shown in FIG.

At this time, if the first and second intake valves 14a and 14b are closed, that is, after the action of the driving force on the arm 47 is started, the first and second intake valves 14a and 14b When the valve is closed, as shown in FIG. 12, the first and second contact portions 47a, 4 of the arm 47 on which the driving force of the driving piston 46 acts.
7b moves from the low-speed position toward the second cam portion 30b, but as shown in FIG. 8, the first contact portion 47a is
The first side surface 52c of the restricting portion 52c remaining in the movement route of 7a
In contact with 1, the arm 47 is further rotated in the axial direction A1.
Occupies a standby position where movement is prevented. At this time, between the first contact portion 47a and the second engagement portion 36, the rotation axis direction A
1, a gap G3 smaller than the gap G1 by the gap G2 is formed.

Thereafter, the camshaft 7 rotates and the low-speed cam 31
The first and second lifters 24 are formed by the nose portions 31a1 and 31b1 of the a and 31b.
When the first and second intake valves 14a and 14b are opened by pressing the first and second intake valves 14a and 14b, the triggers contacting the first and second side wall upper surfaces 24a2 and 24b2 with the first and second contact portions 51c and 51d. The base 51 moves downward while being in contact with the first and second lifters 24a and 24b by the spring force of the trigger spring 53, and the trigger piece 52 also moves downward. When the first and second lifters 24a and 24b are further moved and the first and second intake valves 14a and 14b are opened with a predetermined lift amount, the stopper 52d contacts the upper surface 37c of the holder 37, If the lift amount exceeds that, the downward movement of the trigger base 51 and the trigger piece 52 is prevented, and the first and second contact portions 51
c and 51d are in a non-contact state with the first and second side wall upper surfaces 24a2 and 24b2. At this time, the regulating portion 52c is located below the first contacting portion 47a, the contact between the first contacting portion 47a and the first side surface 52c1 is released, and the arm 47 separates the gap G3 by the driving force. Only the second cam portion 30b is moved toward the second engagement portion 36 to abut on the second engagement portion 36, and a part of the first abutment portion 47a occupies a movable position located directly above the regulating portion 52c. In this state, the arm 47 applies the driving force to the cam piece 22, but the first and second intake valves 14a, 14b
Is open and the spring force of the valve spring 18 is large, while the driving force is set to the above-mentioned magnitude, so that the low-speed cams 31a and 31b and the slipper portions 42a and 42b Of the first and second contact portions 47a, 4
7b remains in contact with the second engagement portion 36, and the cam piece 22
Does not move in the rotation axis direction A1. FIGS. 9 and 13 show the first contact portion 47a and the first and second side wall upper surfaces 2 when the first and second intake valves 14a and 14b are opened with the maximum lift amount.
4a2, 24b2, first and second contact portions 51c, 51 of trigger base 51
The positional relationship between d and the restricting portion 52c of the trigger piece 52 is shown.

After the first and second intake valves 14a and 14b have reached the maximum lift, the low-speed cams 31a and 31b are further rotated to reduce the lift and reach the predetermined lift. The first and second contact portions of the trigger base 51 are formed on the upper surfaces 24a2 and 24b2 of the two side walls.
When the low-speed cams 31a and 31b rotate and the lift amount decreases and the first and second lifters 24a and 24b move upward, the trigger base 51 and the trigger piece 52 both move upward. Then, the upper surface of the restricting portion 52c comes into contact with the outer peripheral surface of the first contact portion 47a located immediately above the restricting portion 52c in the central axis direction A2. At this time, the first and second intake valves 14a, 14b are in the open state, and the frictional force between each of the low-speed cams 31a, 31b and the slipper portions 42a, 42b is larger than the driving force. 46 does not move the cam piece 22 in the rotation axis direction A1.

When the low speed cams 31a and 31b further rotate,
The restricting portion 52c maintains a state of contact with the first contact portion 47a in the central axis direction A2, and only the trigger base 51 moves upward together with the first and second lifters 24a and 24b, and each of the low-speed cams 31a , 31b
FIGS. 10 and 14 show a state immediately before the base circle portions 31a2 and 31b2 are in sliding contact with the two slipper portions 42a and 42b.

Then, the low-speed cams 31a and 31b further rotate, and the base circle portions 31a2 and 31b2 of the low-speed cams 31a and 31b slide in contact with the two slipper portions 42a and 42b.
Immediately after the valves 14a and 14b are closed, the driving force of the driving piston 46 overcomes the frictional force generated between the low-speed cams 31a and 31b and the slipper portions 42a and 42b, and causes the first and second abutments. Part 47
a and 47b press the second engagement 36 to move the cam piece 22 in the rotation axis direction A1, and as shown in FIGS.
The base circle portions 32a2 and 32b2 of the high-speed cams 32a and 32b occupy the high-speed positions where they slide in contact with the two slipper portions 42a and 42b, and the switching from the low-speed cams 31a and 31b to the high-speed cams 32a and 32b is completed. At this time, as shown in FIG.
47a occupies a position near the second lifter 24b, and the first contact portion 47a
A gap G2 in the rotation axis direction A1 having a size equal to the gap G2 in FIG. 11 is formed between a and the second side surface 52c2 of the trigger piece 52. The first engagement portion 35 occupies a position facing the trigger piece 52 in the central axis direction A2, and the trigger piece 52 is not in contact with the cam piece 22.

Thus, the first and second intake valves 14a, 14b are opened and closed at the opening / closing timing and the lift amount determined by the cam profiles of the high-speed cams 32a, 32b. The exhaust-side drive mechanism M _EX also occupies a high-speed position similarly to the intake-side drive mechanism M _IN , so the first and second intake valves in each cylinder 1
The exhaust valves 14a, 14b and the exhaust valve 15 are opened / closed with a large lift amount, opening / closing timing and a long valve opening period that are suitable for the valve operating characteristics in the high speed rotation range.

Then, when the rotation speed of the internal combustion engine E falls below the predetermined rotation speed and shifts from the high-speed rotation range to the low-speed rotation range, the first and second control valves control the first and second control valves.
Since the hydraulic oil in the hydraulic chamber 48a has a low hydraulic pressure and the hydraulic oil in the second hydraulic chamber 48b has a high hydraulic pressure, the drive piston 46 of the intake-side drive mechanism M _IN moves the cam piece 22 in the direction opposite to the above-described moving direction. Is moved so that the trigger piece 52 of the trigger mechanism T and the first contact portion 47 are moved.
The operation similar to the above-mentioned operation is performed in this order from the opposite direction of the rotation axis direction A1, and switching to the low speed cams 31a, 31b is performed by the base circular portions 32a2, 32b2 of the high speed cams 32a, 32b. . Also in the exhaust-side valve operating device V _EX, it is made the same migration and the intake-side valve operating device V _IN above.

When the first and second intake valves 14a, 14b are open, the operating range of the internal combustion engine E shifts between a low speed range and a high speed range, and the control device Even if a command is issued to the first and second control valves to change the hydraulic pressure of the first and second hydraulic chambers 48a and 48b, the magnitude of the driving force of the driving piston 46 is set as described above. , Drive piston 46
Does not move the cam piece 22, and after the camshaft 7 is further rotated and the first and second intake valves 14a and 14b are closed, ie, after the action of the driving force on the arm 47 is started. From the first closing of the first and second intake valves 14a and 14b,
The switching operation of the low-speed cams 31a and 31b and the high-speed cams 32a and 32b is performed through the same process as described above.

Next, the first embodiment constructed as described above is used.
The operation and effect of the embodiment will be described. In addition, below
Is the intake-side valve train V_INThe exhaust side valve train
Place V _EXThe same applies to

The intake drive mechanism M _IN for switching the operating characteristics of the first and second intake valves 14a and 14b by moving the cam piece 22 in the rotation axis direction A1 according to the operating range of the internal combustion engine E starts the switching operation. Is set immediately after the first and second intake valves 14a and 14b are closed by the trigger mechanism T.
a, 31b and base circle portions 31a2, 31b of high-speed cams 32a, 32b
Switching time in 2, 32a2, 32b2 is sufficiently ensured,
Low-speed cams 31a, 31b slidingly contacting the first and second lifters 24a, 24b.
And the high-speed cams 32a and 32b can be reliably switched. The low-speed cams 31a and 31b and the high-speed cams 32a and 32b
Collision with the second lifters 24a, 24b and the first and second lifters 24
The uneven wear of the first and second lifters 24a and 24b is prevented.
The smooth sliding movement of 4b is ensured, and at the same time, generation of abnormal noise and reduction in durability of the first and second lifters 24a and 24b, the low-speed cams 31a and 31b, and the high-speed cams 32a and 32b are prevented.

The first and second intake valves 14a and 14b are held by the lifter holder so as to be movable up and down, and the first and second lifters 24a and 24b to which the low-speed cams 31a and 31b and the high-speed cams 32a and 32b come into sliding contact, respectively. Actuated via the intake side valve train V
The dimension above _IN , that is, the dimension in the center axis direction of the cylinder 1 is reduced, and the cam piece 22 is moved in the rotation axis direction A1 to operate the first and second intake valves 14a and 14b. The trigger mechanism T for setting the switching operation start timing of the intake-side drive mechanism M _IN for switching the characteristics is disposed below the camshaft 7, that is, closer to the cylinder block 2 than the camshaft 7. By utilizing the lower space, the intake-side valve train _VIN having the trigger mechanism T can be downsized, and the valve train 21 and the internal combustion engine E can be downsized. Further, unlike the related art in which the rocker arm support shaft, the trigger lever support shaft, and the cam switching mechanism are arranged around the cam shaft as the shaft members, the cam shaft 7 is provided with a shaft member around the intake side. Since only the drive mechanism M _IN is provided, the intake-side valve train _VIN having the trigger mechanism T can be downsized in this respect as well.

During operation of the internal combustion engine when the intake-side drive mechanism M _IN is not in the switching operation state, the first contact portion 47a of the arm 47 is actuated by the trigger mechanism T as shown in FIGS. Since it does not contact the piece 52, the wear of both is suppressed, and the durability is improved. Further, since the trigger mechanism T does not contact the rotating cam piece 22, wear of the trigger mechanism T is suppressed.

The contact and release of the first contact portion 47a of the trigger piece 52 by the trigger mechanism T are performed by the first and second lifters 24a and 24a.
Since the trigger mechanism T is operated by using the upward and downward movements of the trigger mechanism T, the trigger mechanism T is actuated in conjunction with the first and second lifters 24a and 24b to operate the trigger mechanism T. Since it is not necessary to newly provide a member, the operation mechanism for operating the trigger mechanism T is simplified, and the intake-side drive mechanism M _{IN including the} trigger mechanism T can be reduced in size. Also, the trigger base of the trigger mechanism T
The trigger mechanism T is disposed so as to overlap the first and second lifters 24a and 24b when viewed from the center axis direction A2 so that the first and second side walls 51 abut on the first and second side wall upper surfaces 24a2 and 24b2. The intake-side drive mechanism M _{IN including the} mechanism T can be downsized even in the rotation axis direction A1 of the cam shaft 7.

The trigger base 51 and the trigger piece 52 of the trigger mechanism T are located between the first lifter 24a and the second lifter 24b in the rotation axis direction A1 and the first cam portion 30 of the cam piece 22.
Since the intake valve operating device V _IN provided with the trigger mechanism T can be downsized in the rotational axis direction A1 because the intake cam valve is disposed between the a and the second cam portion 30b in the rotational axis direction A1.

Further, the base circle portion 31 of the low-speed cams 31a, 31b
The first abutting portion 47a and the first and second engaging portions 35 and 36 of the arm 47, which protrude radially from the a2 and 31b2, and the high-speed cams 32a and 32b have the notches 40a1, 40a2 and 40b1. Since the cam pieces 22 are arranged by utilizing them, the width of the cam pieces 22 in the rotation axis direction A1 can be reduced.

The trigger mechanism T is disposed in a space formed between the camshaft 7 and the first and second lifters 24a and 24b in the direction A2 of the center axis, so that the intake-side valve operating device _VIN can be operated. The size can be reduced in the central axis direction A2. Further, since the trigger base 51 comes into contact with the first and second side wall upper surfaces 24a2 and 24b2 formed by providing the notches 40a2 and 40b1, the trigger mechanism T is also arranged using the notches 40a2 and 40b1. Therefore, the intake-side valve train V _IN can be further reduced in the rotation axis direction A1 and the center axis direction A2.

The trigger piece 52 made of a flat plate along the rotation axis direction A1 is disposed so as to protrude from the first and second lifters 24a and 24b toward the cam shaft 7, and reciprocates in the rotation axis direction A1. The first contact portion 47a stays in the movement path of the first contact portion 47a of the arm 47, and the first contact portion 47a on the first and second side surfaces 52c1 and 52c2, which are the edges of the regulating portion 52c in the rotation axis direction A1.
Therefore, the rigidity of the trigger piece 52 in the direction of the rotation axis A1 is high, and the movement of the arm 47 of the intake-side drive mechanism M _IN can be reliably restricted at a predetermined position.

The trigger piece 52 moves the first contact portion 47a.
As long as you only need to be able to stay in the route,
High degree of freedom in shape and arrangement, intake-side valve of various structures
Device V_INIn response to the intake valve valve V_INSmall
Can contribute to Further, the intake side drive mechanism M_INArm
A first contact portion 47a, which is a part of 47, contacts the trigger piece 52.
Therefore, it is not necessary to separately provide a member that contacts the trigger piece 52.
And the intake-side valve train V _INCan be simplified.

Since the trigger mechanism T is fixed to the holder 37 by using the bolt B for fixing the holder 37 to the cylinder head 3, the number of parts and the number of assembling steps can be reduced.
Moreover, since the trigger mechanism T is fixed to the lifter holder having high rigidity to hold the first and second lifters 24a and 24b, the trigger mechanism T can be firmly fixed.

The guide groove 34 in which the fork-shaped first and second contact portions 47a and 47b of the arm 47 for moving the cam piece 22 in the rotation axis direction A1 are accommodated with respect to the trigger piece 52 of the trigger mechanism T. The width of the guide groove 34 in the rotation axis direction A1 can be made as small as possible because the first and second engagement portions 35 and 36 occupy positions facing each other in the center axis direction A2. A1 can be downsized.

Next, a second embodiment of the present invention will be described with reference to FIGS. The second embodiment differs from the first embodiment mainly in the structure of the trigger mechanism T, and has basically the same configuration in the other respects. Therefore, description of the same part is omitted or simplified,
The different points will be mainly described. The same members as those in the first embodiment or corresponding members have the same reference numerals.

Referring to FIGS. 16 to 18, each of the holder portions 60 of the lifter holder is formed on the holder portion 60 on a plane orthogonal to the central axis direction A2 at intervals in a direction orthogonal to the rotation axis direction A1. It is fixed to the cylinder head 3 by bolts B inserted into the two through holes 60a. Then, the trigger mechanism T includes the first and second guide holes 39a, 3
9b, the trigger body 61 is formed at a position of the holder portion 60 near the center axis of the cylinder 1 and is slidably fitted in a receiving hole 60b formed of a circular hole having a center axis in the center axis direction A2. , A cylindrical trigger piece 62 slidably fitted to the trigger body 61, a first trigger spring 63 made of a tension coil spring, and a second trigger spring 64 made of a compression coil spring.
And a plate 65 fixed to the holder unit 60.

The trigger body 61 has a cylindrical tubular portion 61a fitted into the housing hole 60b, and a flat flange portion 61b integrally formed at the upper end of the tubular portion 61a. The flange portion 61b
Are a first arc portion 61b1 and a second arc portion facing each other in a direction orthogonal to the rotation axis direction A1 when viewed from the center axis direction A2.
61b2, and are connected to the first and second circular arc portions 61b1 and 61b2 at both ends in the orthogonal direction, respectively.
3, 61b4. And the flange part 61b
However, the trigger body 61 is prevented from rotating by being slidably fitted to the flange portion 61b and the concave portion 61c having the same shape as viewed from the center axis direction A2 formed on the holder portion 60.

The width of the flange portion 61b in the rotation axis direction A1 is
As with the support portion 51a of the first embodiment, the first and second cam portions 30
a, outside of the rotation path of 30b,
Part of both side edges in the rotation axis direction A1 having the first and second linear portions 61b3, 61b4
a first abutment portion which abuts on the first and second side wall upper surfaces 24a2 and 24b2 opposed to each other in the rotation axis direction A1 in the directions a and 24b;
61c and the second contact portion 61d are set.
Therefore, in the range of the first and second contact portions 61c and 61d, the concave portions
60c crosses the guide holes 39a and 39b, and the portion is cut out. The locking pin 66 press-fitted into the cylindrical portion 61a and the locking pin 67 press-fitted into the holder portion 60
With the spring force of the first lifter spring 63 stretched between
The first and second contact portions 61c and 61d of the flange portion 61b are urged to contact the first and second side wall upper surfaces 24a2 and 24b2 of the first and second lifters 24a and 24b.

The trigger piece 62 disposed between the first cam portion 30a and the second cam portion 30b in the rotation axis direction A1 has a top wall 62a1 and is slidable in an inner hole 61e of the cylindrical portion 61a. And a plate-like restricting portion 62b projecting upward from the upper surface of the piston portion 62a. Trigger piece 62
One end abuts and is supported by a spring receiving portion 61f formed of an inwardly projecting flange formed at a portion where the locking pin 66 of the cylindrical portion 61a is press-fitted, and the other end is a lower surface of the top wall 62a1. And is urged upward by the spring force of the second trigger spring 64 which comes into contact with the second trigger spring 64. The maximum upper position of the trigger piece 62 is
The upper surface of the top wall 62a1 comes into contact with the retaining ring 68 mounted on the upper part of the a. Further, the width of the regulating portion 62b in the rotation axis direction A1 is set in the same manner as the width of the regulating portion 52c of the first embodiment.

After the trigger mechanism T is assembled to the holder part 60, the trigger piece 62 is covered with a plate 65 having a guide hole 65a into which the restriction part 62b is inserted. The plate 65 has a through hole 60a near the center axis of the cylinder 1.
Is fixed to the holder part 60 by a bolt B inserted into the holder part 60.
The guide hole 65a has an area slightly larger than the cross-sectional area of the restricting portion 62b, and has a function of preventing the trigger piece 62 from rotating.

On the peripheral wall surfaces of the first and second guide holes 39a and 39b,
Insertion grooves 39a2, 39b2 having a semicircular cross section extending in the central axis direction A2 and having an open upper end in the central axis direction A2 and having end wall surfaces at the lower end are formed, while the slipper portions 42a, 4
The outer surfaces of the side walls of the first and second lifters 24a and 24b connected to 2b have a semicircular cross section at a position radially opposed to the insertion grooves 39a2 and 39b2, similarly to the insertion grooves 39a2 and 39b2. At the same time, the upper end in the central axis direction A2 is opened, and locking grooves 24a3 and 24b3 having end wall surfaces at the lower end are formed. And the insertion groove 39a
A locking pin 69 having a length slightly shorter than the length of the insertion grooves 39a2 and 39b2 is inserted into the second and 39b2.
Is disposed over the insertion grooves 39a2, 39b2 and the locking grooves 24a3, 24b3 having a length that enables the first and second lifters 24a, 24b to move in the central axis direction A2. The pin 69 prevents the first and second lifters 24a and 24b from rotating with respect to the holder portion 60. In order to prevent the pin 69 from coming off, the plate 65 is provided with a holding portion 65b at a position covering a part of the end surface of the pin 69. Also, this plate 65
This prevents the trigger body 61 from protruding toward the camshaft 7 due to the vibration of the internal combustion engine E or the like due to the contact of the flange portion 61b of the trigger body 61.

On the other hand, as shown in FIG. 19, the arm 47 of the intake side drive mechanism M _IN
A third projecting downward toward the position near the drive piston 46
A contact portion 47c is formed, and the third contact portion 47c is
It abuts on the first side surface 62b1 of b and occupies the same standby position as in the first embodiment. Here, the radial width of the first and second contact portions 47a and 47b is shown in FIG. 22 (only the first contact portion 47a is shown in FIG. 22). Engaging parts 35, 36
And the amount of downward projection of the third contact portion 47c is set to be greater than the amount of downward projection of the first and second contact portions 47a and 47b. The width of the third contact portion 47c in the rotation axis direction A1 is at least a portion in contact with the first and second side surfaces 62b1 and 62b2 of the restricting portion 62b, and the first contact of the first embodiment.
It is set equal to the corresponding part of the contact part 47a.

Therefore, when the trigger mechanism T is assembled to the holder portion 60 and the first and second intake valves 14a and 14b are closed with the plate 65 covered, the first trigger spring 63 is closed.
Of the trigger body 61, the first and second abutting portions 61c and 61d of the flange portion 61b are moved by the first and second side wall upper surfaces 24a.
2 and 24b2, and the trigger piece 62 is urged by the spring force of the second trigger spring 64 so that the top wall 62a1 contacts the retaining ring 68. In this state, the first and second side surfaces 62b1 and 62b2 of the restricting portion 62b are located within the movement path of the third contact portion 47c.

Then, the trigger body 61 and the trigger piece 62
When the first and second intake valves 14a and 14b are opened,
The first and second contact portions 61c and 61d of the first side wall 61b are formed on the first and second side wall upper surfaces 2.
4a2, move down inside the inner hole 61e in contact with 24b2,
When the first and second lifters 24a and 24b move by the predetermined lift amount before moving by the maximum lift amount, the flange portion 61b
Abuts against the bottom surface of the concave portion 60c of the holder portion 60, thereby preventing the trigger piece 62 from moving downward. Therefore, if the lift amount exceeds the predetermined lift amount, the first and second contact portions 61
c and 61d are in non-contact with the first and second side wall upper surfaces 24a2 and 24b2. Therefore, the flange portion 61b has the function of the stopper portion 52d of the first embodiment, and furthermore, has the trigger body 61d.
Functions as a control member that controls the movement of the trigger piece 62 in conjunction with the movement of the first and second lifters 24a and 24b. The predetermined lift amount is appropriately set on condition that the restricting portion 62b of the trigger piece 62 occupies a position below the third contact portion 47c of the arm 47 at the predetermined lift amount.

The operation of the second embodiment is described with reference to FIG.
22, the operating state of the intake side drive mechanism M _IN and the position of the cam piece 22 at the low-speed position, the standby position and the high-speed position are the same as those in the first embodiment. The description will focus on the relationship between and the third contact portion 47c.

As shown in FIG. 22A, when the operating range of the internal combustion engine E is in the low-speed rotation range, the first contact portion 47a contacts the second engagement portion 36, while the first contact portion 47a contacts the second engagement portion 36. A gap G1 having a predetermined width in the rotation axis direction A1 is formed between the portion 47a and the second engagement portion 36, and a first side surface 62b1 of the regulating portion 62b and a third contact portion 47c are formed.
Between, the rotation axis direction of a predetermined width smaller than the gap G1
A gap G2 at A1 is formed. The first and second contact portions 61c and 61d of the flange portion 61b are connected to the first and second side wall upper surfaces 24a2,
It is in contact with 24b2.

When the operating range of the internal combustion engine E shifts to the high-speed rotation range, the driving force of the driving piston 46 is applied to the arm 47.
Act on. At this time, if the first and second intake valves 14a and 14b are closed, that is, after the action of the driving force on the arm 47 is started, when the first and second intake valves 14a and 14b are first closed, As shown in FIG. 22 (B), the arm 47 moves toward the second cam portion 30b, and the third contact portion 47c is restricted in the movement path of the third contact portion 47c. The arm 47 is in contact with the first side surface 62b1 of the shaft 62b, and the arm 47 is further rotated in the direction A1
Occupies a standby position where movement of the vehicle is prevented. At this time, the first
Between the contact portion 47a and the second engagement portion 36, the rotation axis direction A1
Then, a gap G3 smaller than the gap G1 by the gap G2 is formed.

Thereafter, the camshaft 7 rotates and the low-speed cam 31
The first and second lifters 24 are formed by the nose portions 31a1 and 31b1 of the a and 31b.
When the first and second intake valves 14a and 14b are opened by pressing the first and second intake valves 14a and 14b, the trigger that is in contact with the first and second side wall upper surfaces 24a2 and 24b2 by the first and second contact portions 61c and 61d. The body 61 moves downward together with the trigger piece 62 while being in contact with the first and second lifters 24a and 24b by the spring force of the first trigger spring 63. When the first and second lifters 24a and 24b move further downward and the first and second intake valves 14a and 14b are lifted by the predetermined lift amount, the flange portion 61b contacts the bottom surface of the recess 60c, If the lift amount exceeds that, the downward movement of the trigger body 61 and the trigger piece 62 is prevented. At this time, the regulation unit 62
b is located below the third contact portion 47c, and the third contact portion 47c
The contact between the arm 47 and the first side surface 62b1 is released, and the arm 47 moves toward the second cam portion 30b by the gap G3 by the driving force to contact the second engagement portion 36, and the third contact portion A part of 47c occupies a movable position located directly above the restricting portion 62b. In this state, the arm 47 applies the driving force to the cam piece 22, but since the first and second intake valves 14a and 14b are open, the low-speed cams 31a and 31b and the slipper portions 42a and 42b Between the first and second contact portions 47a, 4
7b remains in contact with the second engagement portion 36, and the cam piece 22
Does not move in the rotation axis direction A1. FIGS. 20 and 22C show the third contact portion 47c and the first and second intake valves 47a and 14b when the first and second intake valves 14a and 14b are opened with the maximum lift amount.
The positional relationship between the side wall upper surfaces 24a2 and 24b2, the first and second contact portions 61c and 61d of the flange portion 61b, and the restricting portion 62b of the trigger piece 62 is shown.

After the first and second intake valves 14a and 14b reach the maximum lift amount, the low-speed cams 31a and 31b are further rotated to reduce the lift amount and reach the predetermined lift amount. 2
The side wall upper surfaces 24a2 and 24b2 abut against the first and second abutment portions 61c and 61d of the flange portion 61b, and the low-speed cams 31a and 31b rotate to reduce the lift amount, thereby reducing the first and second lifters 24a and 24b. When 24b moves upward, both the trigger body 61 and the trigger piece 62 move upward, and the upper surface of the restricting portion 62b contacts the lower surface of the third contact portion 47c located immediately above the restricting portion 62b in the central axis direction A2. . At this time, the first and second intake valves 14a and 14b are in the open state, and the friction force between each of the low-speed cams 31a and 31b and the slipper portions 42a and 42b is larger than the driving force. 22 does not move in the rotation axis direction A1.

When the low speed cams 31a and 31b further rotate,
The restricting portion 62b maintains a state of contact with the third contact portion 47c in the central axis direction A2, and only the trigger body 61 moves upward together with the first and second lifters 24a and 24b, and each of the low-speed cams 31a , 31b
FIG. 21 and FIG. 22 (D) show a state immediately before the base circle portions 31a2 and 31b2 contact the two slipper portions 42a and 42b.

Immediately after the low-speed cams 31a and 31b further rotate and the first and second intake valves 14a and 14b close, the driving force of the driving piston 46 is applied to both the low-speed cams 31a and 31b. The first and second contact portions 47a and 47b press the second engagement portion 36 to overcome the frictional force generated between the slipper portions 42a and 42b and move the cam piece 22 in the rotation axis direction A1. FIG. 22
As shown in (E), the base circle portions 32a2, 32b2 of both high-speed cams 32a, 32b occupy the high-speed position where they are in sliding contact with the two slipper portions 42a, 42b, respectively.
Switching to 32a and 32b is completed. At this time, the third contact portion 47
c occupies a position closer to the second lifter 24b, and the third contact portion 47c
A gap G2 in the rotation axis direction A1 having a size equal to that of the gap G2 in FIG. 22A is formed between the gap G2 and the second side surface 62b2 of the regulating portion 62b.

Further, when the rotation speed of the internal combustion engine E falls below the predetermined rotation speed and shifts from the high-speed rotation range to the low-speed rotation range, the trigger piece of the trigger mechanism T is operated in the same manner as in the first embodiment. The same operation as described above is performed between the second contact portion 62c and the third contact portion 47c from the opposite direction of the rotation axis direction A1. Switching to 31b is performed.

When the operating range of the internal combustion engine E shifts between the low-speed rotation range and the high-speed rotation range while the first and second intake valves 14a and 14b are open, the first embodiment is also performed. As in the example,
The drive piston 46 does not move the cam piece 22, and the camshaft 7 further rotates to close the first and second intake valves 14a and 14b, that is, the action of the drive force on the arm 47. After the start, after the first and second intake valves 14a, 14b are first closed, the low-speed cam 31
The switching operation between a and 31b and the high-speed cams 32a and 32b is performed.
According to the second embodiment, except for the operation and effect of the trigger mechanism T of the first embodiment being formed from a plate material, the first embodiment is similar to the first embodiment.
The same operation and effect as in the embodiment can be obtained.

Hereinafter, an embodiment in which a part of the configuration of the above-described embodiment is changed will be described with respect to the changed configuration.
In the first embodiment, as shown in FIG. 23, the trigger bracket 50 may be integrally formed with a retaining portion 50c that covers the upper surface of the pin 43 and prevents the pin 43 from coming off. In this case, similarly to the second embodiment, the peripheral wall surfaces of the first and second guide holes 39a and 39b extend in the central axis direction A2, have a semicircular cross section, and are open at the upper end in the central axis direction A2. Insertion grooves 39a3, 39b3 having end wall surfaces at the lower end are formed, while the outer surfaces of the side walls of the first and second lifters 24a, 24b connected to the slipper portions 42a, 42b have the same diameter as the insertion grooves 39a3, 39b3. Opposite in the direction, locking grooves 24a4, 24b4 having a semicircular cross section like the insertion grooves 39a3, 39b3 and having an upper end open in the central axis direction A2 and having an end wall surface at the lower end are formed. . And
A detent pin 70 having a length slightly shorter than the length of the insertion grooves 39a3, 39b3 is inserted into the insertion grooves 39a3, 39b3. The pin 70 is inserted into the insertion grooves 39a3, 39b3 and the first and second grooves. Lifter 24
a, 24b are arranged so as to extend over the locking grooves 24a4, 24b4 having a length enabling the movement of the first and second lifters 24a, 24b in the central axis direction A2. Rotation with respect to the part 37 is prevented. Further, by forming the pin 43 itself and the trigger bracket 50 integrally, the number of components can be reduced.

In each of the above embodiments, the lifter is moved in the direction of the center axis.
Although the member slidably fitted to A2 is a lifter holder fixed to the cylinder head 3, the lifter holder may be omitted, and a guide hole into which the lifter is fitted may be formed in the cylinder head 3. In this case, the cylinder head 3 forms a lifter holding member.

The intake valve and the exhaust valve may be an internal combustion engine provided one for each cylinder, or an internal combustion engine provided with at least one of the intake valve and the exhaust valve for one cylinder May be
Further, the lifter may have a top wall in which a notch is not formed.

[Brief description of the drawings]

FIG. 1 shows a first embodiment of the present invention, and is a partial longitudinal sectional view of an internal combustion engine to which a direct-acting valve train of the present invention is applied.

FIG. 2 is a partially exploded view of the intake-side valve train.

FIG. 3 is a diagram illustrating a positional relationship between an intake-side drive mechanism and a cam piece when an operation range of the internal combustion engine is a low-speed rotation range.

FIG. 4 is a diagram illustrating a positional relationship between an intake-side drive mechanism and a cam piece when an operation range of the internal combustion engine is a high-speed rotation range.

FIG. 5 is an exploded perspective view of a trigger mechanism of the direct acting valve operating apparatus of FIG. 1;

6 is a perspective view of a main part showing a state before the trigger mechanism of FIG. 5 is assembled to the lifter holder of the direct acting valve operating device of FIG. 1;

FIG. 7 is a plan view of a main part of a lifter holder to which the trigger mechanism of FIG. 5 is assembled.

FIG. 8 is a sectional view taken along line VIII-VIII in FIG. 7;

FIG. 9 is a view similar to FIG. 8 at the time of the maximum lift of the intake valve.

FIG. 10 is a view similar to FIG. 8, immediately before closing of an intake valve.

FIG. 11 is for explaining the operation of the trigger mechanism;
FIG. 8 is a cross-sectional view of a main part along line XI-XI in FIG. 7 when the valve is closed when the operation range of the internal combustion engine is a low-speed rotation range.

FIG. 12 is a view similar to FIG. 11, but immediately after the operating range of the internal combustion engine has shifted from the low-speed rotation range to the high-speed rotation range and at the time of the first valve closing after the start of the application of the driving force to the arm.

FIG. 13 is a view similar to FIG. 11 when the intake valve is opened with the maximum lift from the state of FIG. 12;

FIG. 14 is a view similar to FIG. 11 immediately before closing of an intake valve.

FIG. 15 is a view similar to FIG. 11 when the switching from the low-speed cam to the high-speed cam is completed.

FIG. 16 is an exploded perspective view of a trigger mechanism of the direct-acting valve train according to the second embodiment of the present invention.

17 is a perspective view of a main part showing a state where the trigger mechanism of FIG. 16 is assembled to a lifter holder of the direct acting valve operating device.

FIG. 18 is a plan view of a main part of a lifter holder to which the trigger mechanism of FIG. 16 is assembled.

19 is a sectional view taken along line XIX-XIX in FIG.

FIG. 20 is a view similar to FIG. 19 at the time of the maximum lift of the intake valve.

FIG. 21 is a view similar to FIG. 19, immediately before the intake valve is closed.

FIG. 22 is a sectional view for explaining the operation of the trigger mechanism according to the second embodiment, which is a principal part corresponding to FIGS. 11 to 15 in the first embodiment;

FIG. 23 shows a third embodiment of the present invention, and is a perspective view of a main part of a lift holder to which a trigger mechanism is attached.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Cylinder, 2 ... Cylinder block, 3 ... Cylinder head, 4 ... Head cover, 5 ... Piston, 6 ... Connecting rod, 7, 8 ... Cam shaft, 9, 10 ... Cam holder, 11 ... Combustion chamber, 12 ... Intake port, 13 ... exhaust port, 14 ... intake valve, 15
... Exhaust valve, 16, 17 ... Valve guide, 18,19 ... Valve spring, 20 ... Spark plug, 21 ... Valve operating chamber, 22,23 ... Cam piece, 24,25 ... Lifter,
26, 27 ... spring receiver, 30a, 30b ... cam part, 31a, 31b ..., 32
a, 32b: High-speed cam, 33: Cylindrical part, 34: Guide groove, 35, 36 ...
Engaging part, 37: holder part, 38: connecting part, 39a, 39b: guide hole, 40a1, 40a2, 40b1, 40b2: notch, 42a, 42b: slipper part, 43: pin, 45a, 45b: cylinder part, 46: drive piston, 47: arm, 47a, 47b, 47c: contact part, 48a, 48
b: Hydraulic chamber, 49a, 49b: Opening, 50: Trigger bracket, 51: Trigger base, 52: Trigger piece, 52c: Regulator, 6
0: Holder, 61: Trigger body, 62: Trigger piece, 63, 6
4 Trigger spring, 65 plate, 66, 67 locking pin, 68
... retaining ring, 69, 70 ... pin, E ... internal combustion engine, V _IN , V _EX ...
Valve train, M _IN , M _EX … Drive mechanism, T… Trigger mechanism, L1
... Rotating axis, L2 ... Center axis, A1 ... Rotating axis direction, A2 ... Center axis direction, d1 ... Space, W1 ... Width, G1-G3 ... Gap, B ... Bolt.

 ────────────────────────────────────────────────── ─── Continuing on the front page (72) Inventor Junichi Iwamoto 143 Hagadai, Haga-cho, Haga-gun, Tochigi F-term within PSG (reference) 3G016 AA02 AA08 AA12 AA19 BA03 BA19 BA25 BA33 BA34 BA36 BB04 BB06 BB07 CA02 CA06 CA12 CA14 CA16 CA21 CA22 CA25 CA29 CA57 DA06 FA37 FA38 FA39 GA01 3G018 AA06 AB07 AB17 BA04 BA09 BA24 BA34 CA06 CA19 DA03 DA17 DA18 DA51 DA70 DA83 DA85 DA86 EA03 EA04 FA03 FA06 GA14 GA17 GA18

Claims (5)

[Claims] 1. A cam piece mounted on a cam shaft rotatably supported by a cylinder head so as to be movable in the direction of a rotation axis thereof and to rotate together with the cam shaft, wherein a plurality of cams having different cam profiles are provided. Is disposed between a cam piece having a cam portion provided adjacently in the rotation axis direction and an engine valve for controlling intake or exhaust of an internal combustion engine, and is held by a lifter holding member so as to be vertically movable. A lifter, and switching means for moving the cam piece in the direction of the rotation axis to selectively switch the cam sliding on the lifter of the cam portion, wherein the engine valve slides on the lifter. In a direct-acting valve train for an internal combustion engine that is operated according to a cam profile of a cam, a trigger mechanism for setting a switching operation start timing of the switching means when the engine valve is closed, Direct acting valve gear of an internal combustion engine, characterized in that the serial is disposed below the cam shaft. 2. The direct-acting valve train of an internal combustion engine according to claim 1, wherein the trigger mechanism is disposed between the camshaft and the lifter. 3. The trigger mechanism according to claim 1, wherein the trigger mechanism is provided at a position overlapping with the lifter when viewed from a direction in which the lifter moves up and down, and operates in conjunction with movement of the lifter. 3. A direct-acting valve train for an internal combustion engine according to claim 2. 4. A first cam portion and a second cam portion provided in series in the rotation axis direction on the cam piece.
A cam portion, wherein the engine valve includes a first engine valve and a second engine valve provided for the same cylinder, and wherein the lifter is disposed between the first engine valve and the first cam portion. A first lifter and a second lifter disposed between the second engine valve and the second cam portion, wherein the trigger mechanism includes the first lifter and the second lifter in the rotation axis direction. The direct-acting valve train of an internal combustion engine according to any one of claims 1 to 3, wherein the valve train is arranged between the direct-acting valve train and the internal combustion engine. 5. The lifter holding member is constituted by a member separate from a cylinder head of the internal combustion engine, and the trigger mechanism is configured by a fixing member for fixing the lifter holding member to the cylinder head. 5. The method according to claim 1, wherein
A direct-acting valve train for an internal combustion engine according to claim 1.