JPH0578904U - Rocker arm support structure - Google Patents

Abstract

(57) [Summary] [PROBLEMS] To provide a rocker arm support structure in which a camshaft holder and the like can be shared by an engine having a valve opening / closing timing changing mechanism and an engine having a valve operation stopping mechanism. [Structure] A rocker shaft 3 supported by a journal portion of a camshaft holder and a rocker shaft cap.
A rocker arm assembly 1 with a valve opening / closing timing changing mechanism, in which a rocker arm 5 and a high-speed rocker arm 6 are mounted on the rocker arm 3, and a rocker arm 10 on the rocker shaft 3.
The low-speed rocker arm 11 and the high-speed rocker arm 12 have the same axial length as the rocker arm assembly 2 with a valve operation stopping mechanism.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a rocker arm support structure in which a camshaft holder and the like can be shared by an engine having a valve opening / closing timing changing mechanism and an engine having a valve operation stopping mechanism.

[0002]

[Prior Art]

 Generally, the opening / closing control of the intake valve and the exhaust valve in an automobile engine is set according to the operating state obtained from the engine speed and the accelerator pedal depression amount. In addition, in such a valve operating system, it has been proposed to change the cam profile in order to reduce fuel consumption at low speeds and to perform efficient intake and exhaust at high speeds according to operating conditions. .. This is done by changing the opening / closing timing of the intake and exhaust valves, the lift amount, the opening period, etc. at low speed or high speed.

That is, in an automobile engine, a high speed cam and a low speed cam are provided on a cam shaft, and the high speed cam has a cam profile capable of obtaining a valve opening / closing timing corresponding to a high speed operation. The cam has a cam profile that can obtain the valve opening / closing timing corresponding to low speed operation. Then, by selectively using the high-speed cam or the low-speed cam according to the operating state while the engine is operating, it is possible to obtain the optimum opening / closing timing of the intake valve and the exhaust valve. Is becoming

Specifically, for example, a base end of a rocker arm is fixed to a rocker shaft, a rocker arm for high speed is provided so as to be connectable and separable, and a rocking end of the rocker arm is brought into contact with an upper end portion of a valve for low speed The cam and the high speed cam are engaged with the low speed rocker arm and the high speed rocker arm. That is, at low speeds, the low speed cam swings the rocker arm to open and close the valve.At high speeds, the high speed rocker arm is connected to the rocker shaft and the high speed cam swings the rocker arm. Then, the valve is opened and closed.

In addition, in such an automobile engine, a cylinder deactivation mechanism that reduces fuel consumption by stopping two cylinders of a 4-cylinder engine during idle operation or low-load operation is conventionally used. More suggested. That is, in the valve train, the piston is operating during idle operation or low load operation, but the operation of the intake valve and exhaust valve is stopped so that fuel is not supplied.

As a specific structural example, the base end of the rocker arm is fixed to the rocker shaft, the low speed rocker arm and the high speed rocker arm are provided so as to be coupled and separable, and the rocking end of the rocker arm is provided at the upper end of the valve. The structure is such that the low-speed cam and the high-speed cam are brought into contact with each other and coupled to the low-speed rocker arm and the high-speed rocker arm, respectively. In this structure, at low speeds, the low speed rocker arm is connected to the rocker shaft, the low speed cam opens and closes the valve, and at high speed the high speed rocker arm is connected to the rocker shaft and the high speed cam opens and closes the valve. By separating the low-speed rocker arm and the high-speed rocker arm from the rocker shaft, the stopped state of the valve operation, that is, the deactivated cylinder state is achieved.

[0007]

[Problems to be solved by the device]

 By the way, when manufacturing an engine having the valve opening / closing timing changing mechanism and an engine further having a valve operation stopping mechanism, the cylinder head must be manufactured separately because the rocker arm layout is different. It could not be shared.

[0008]

[Means for Solving the Problems]

 In order to solve the above-mentioned problems, the present invention provides a structure in which both end portions of a rocker shaft are held by a plurality of journal portions provided on a camshaft holder attached to a cylinder head and rocker shaft caps fitted over these journal portions. A rocker arm and a high-speed rocker arm, a rocker arm and a low-speed rocker arm, or a high-speed rocker arm are formed on the rocker shaft according to the dimension between the journal portions.

[0009]

[Action]

 According to this structure, the same camshaft holder and the like can be used in an engine having only the valve opening / closing timing changing mechanism and also in an engine having the valve operation stopping mechanism.

[0010]

【Example】

 FIG. 1 shows a rocker arm assembly in a rocker arm support structure according to an embodiment of the present invention. FIG. 1 (A) shows a rocker arm assembly 3 having only a valve opening / closing timing changing mechanism, and FIG. 1 (B) shows a rocker arm assembly 2 further having a valve operation stopping mechanism.

The rocker arm assembly 1 is formed by integrally mounting a base end of a rocker arm 5 having a collar portion 4 on a rocker shaft 3 and adjoining a rocker arm 5 so that a high speed rocker arm 6 can be coupled and separated. The other end of the rocker arm 5 is a portion that comes into contact with the stem end of the valve, and an adjust nut 7 for that purpose is provided. The rocker arm 5 is operated at a low speed and the like, and is provided with a roller bearing 8 which is engaged with a low speed cam. The high speed rocker arm 6 includes a roller bearing 9 that contacts the high speed cam. The length from the end surface of the collar portion 4 of the rocker arm assembly 1 to the end surface of the high speed rocker arm 6 is "L".

In the rocker arm assembly 2 with a valve operation stopping mechanism, the base end of the rocker arm 10 is integrally mounted on the rocker shaft 3, and the rocker arm 11 for low speed and the rocker arm 12 for high speed are mounted on both sides of the rocker arm 10. It is attached so that it can be connected and separated. The other end of the rocker arm 10 is a portion that comes into contact with the stem end of the valve, and is provided with an adjust nut 7. The low speed rocker arm 11 and the high speed rocker arm 12 are provided with roller bearings 13 and 14 at their tips, and the roller bearings 13 and 14 are brought into contact with the low speed cam and the high speed cam. Like the rocker arm assembly 1, the length from the end surface of the low speed rocker arm 11 to the end surface of the high speed rocker arm 12 of the rocker arm assembly 2 is “L”.

On the other hand, FIGS. 2 to 5 show a cam shaft holder or the like on which the rocker arm assemblies 1 and 2 are supported. Reference numeral 15 is a cylinder head, on which a camshaft holder 16 is mounted. Rocker shaft journal portions 17 are formed on the lower surface of the camshaft holder 16 at regular intervals along the crankshaft direction of the engine, and the adjacent journal portions 17 have rocker shaft journals 3 of the rocker arm assembly 1 or 2. Both ends are fitted and held by attaching the rocker shaft cap 18 to the camshaft holder 16.

The camshafts 19 and 20 are assembled on the upper surface of the camshaft holder 16 and held by the cam cap 21. The cam shafts 19 and 20 include rocker arms 5 on the cam shafts 3 of the rocker arm assemblies 1 and 2, roller bearings 8 and 9 of rocker arms 6 for high speed, or roller bearings of rocker arms 11 and 12 for low speed and high speed. Low-speed and high-speed cams 22 and 23 that come into contact with 13 and 14 are formed.

2 and 3 show a state in which only the rocker arm assembly 1 without a valve operation stopping mechanism is assembled. In FIG. 2, the right side shows the intake side and the left side shows the exhaust side. In FIG. 2, reference numeral 24 denotes a lost motion mechanism for keeping the high-speed rocker arm 6 in contact with the high-speed cam 23 when the high-speed rocker arm 6 is separated from the cam shaft 3, and is held by the cam cap 21. The separation of the high speed rocker arm 6 from the camshaft 3 is performed by, for example, hydraulic pressure and spring force, and an oil control valve 25 for that purpose is attached to the end of the camshaft holder 16. FIG. 3 shows a plane of the rocker arm assembly 1 and also the contact state between the adjust nut 7 at the end of the rocker arm 5 and the stem end of the valve 26.

FIG. 5 and FIG. 6 show an engine in which the rocker arm assembly is changed to the one having the valve operation stopping mechanism so that the first and fourth cylinders can be deactivated. The cam shaft holder 16, the rocker shaft cap 18, etc. can be shared as they are. However, since it is necessary to act the lost motion mechanism 24 on the low-speed rocker arm 11 when the cylinder is deactivated, the two cam caps 21 are provided with the lost motion mechanism holding portion, and another one. It is necessary to replace it with the one 21a provided. Further, since the oil control valve 27 for the cylinder deactivation is required, it is mounted on the end portion of the camshaft holder 16 or the like.

FIG. 6 shows a plane of the rocker arm assembly 2 and also the contact state between the adjust nut 7 at the end of the rocker arm 10 and the stem end of the valve 26. In this embodiment, as shown in the figure, in the rocker arm assembly 2 with the valve operation stopping mechanism, the contact point between the adjusting nut 7 and the stem end is the valve operation stopping mechanism with respect to the center of the stem end. It is arranged so that it is shifted by d ₃ on the opposite side to the one without. This is because by shifting to the opposite side, the thickness of the low speed rocker arm 11 is increased to improve the rigidity. Of course, there is no difference in the valve opening / closing function.

[0018]

[Effect of the device]

 According to the rocker arm support structure of the present invention, the axial dimensions of the rocker arm assembly are the same for those with a valve operation stopping mechanism and those without, so that a camshaft holder or the like can be shared. It is advantageous in terms of production and cost.

[Brief description of drawings]

FIG. 1 is a plan view of a rocker arm assembly according to an embodiment.

FIG. 2 is a plan view of a cylinder head of an engine having no valve deactivation mechanism.

FIG. 3 is an explanatory diagram of an arrangement of rocker arms and the like in an assembled state and a relationship with a valve.

4 is a cross-sectional view taken along the line AA of FIG.

FIG. 5 is a plan view of a cylinder head of an engine having a valve deactivation mechanism.

FIG. 6 is an explanatory diagram showing an arrangement of rocker arms and the like in an assembled state and a relationship with a valve.

[Explanation of symbols]

1 Rocker arm assembly having a valve opening / closing timing changing mechanism 2 Rocker arm assembly having a valve actuation stop mechanism 3 Rocker shaft 5 Rocker arm 6 High speed rocker arm 8, 9 Roller bearing 10 Rocker arm 11 Low speed rocker arm 12 High speed rocker arm 13, 14 Roller Bearing 15 Cylinder head 16 Cam shaft holder 17 Rocker shaft journal 18 Rocker shaft cap 19,20 Cam shaft 21 Cam cap 22 Low speed cam 23 High speed cam

Claims (1)

[Scope of utility model registration request] 1. A structure in which both end portions of a rocker shaft are held by a plurality of journal portions provided on a camshaft holder attached to a cylinder head and rocker shaft caps fitted over these journal portions,
A rocker arm support structure comprising a rocker arm and a high-speed rocker arm, a rocker arm and a low-speed rocker arm, or a high-speed rocker arm on a rocker shaft according to the dimension between the journal portions.