JP2004245074A - Variable valve gear for engine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To form a compact cam cap by integrating a cam journal lubricating oil passage and a lock pin releasing oil passage for common use, and to provide a variable valve gear for an engine having a compatibility of engine starting stability and lubricating performance. <P>SOLUTION: The valve gear has: a first control circuit 90 including first control valves 23 and 24 to supply and discharge working oil to and from a phase variable mechanism; and a second control circuit 110 including a second control valve 120 to supply and discharge working oil to and from a lock releasing chamber 54. An oil passage 123 inside a cam shaft in the second control circuit 110 is branched and communicated to a bearing lubricating oil passage 124 provided inside the cam shaft. A control means 113 to control opening and closing, and an opening degree of the second control valve 120 is provided, and the control means 113 open-controls the opening degree of the second control valve 120 into a throttling state until complete explosion at least when the engine is started. <P>COPYRIGHT: (C)2004,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention belongs to the technical field of a variable valve operating device for an engine that makes opening and closing timings of intake and exhaust valves variable.
[0002]
[Prior art]
2. Description of the Related Art In recent years, an engine for a vehicle or the like is sometimes provided with a variable valve apparatus that can change the opening / closing timing of intake / exhaust valves. This variable valve device generally has a phase variable mechanism that varies the phase of a camshaft with respect to a crankshaft. The hydraulic variable phase mechanism provided at the end of the camshaft includes a case (crankshaft-side rotating member) integrated with a cam sprocket that is linked to the rotation of the crankshaft by a chain, and is housed in the case. The case includes an integral rotor (camshaft-side rotating member), and the case and the rotor form an advance hydraulic chamber and a retard hydraulic chamber. The phase of the camshaft with respect to the crankshaft changes by controlling a hydraulic control valve (first control valve) that supplies and discharges operating pressure to and from these hydraulic chambers. The variable valve apparatus includes the first control valve, and includes an advance oil passage, a retard oil passage, and the like that communicate the first control valve with the advance hydraulic chamber and the retard hydraulic chamber. A hydraulic control circuit (first control circuit) is formed.
[0003]
By the way, as shown in Patent Literature 1, such a phase variable mechanism may be provided with a lock pin mechanism for coupling a case and a rotor under predetermined conditions. This lock pin mechanism is used, for example, at the time of engine start, at least until the engine completely explodes, by integrating the case and the rotor to prevent the generation of abnormal noise due to the rattling of the rotor, and thus to enhance the engine startability. Can be In the lock pin mechanism described in Patent Document 1, the lock state is established when the lock pin accommodated in the rotor enters the hole of the case member by the urging force of the spring. When an operating pressure controlled by a hydraulic control valve (second control valve) is supplied through an oil passage communicating with a lock release chamber provided in the hole, the lock pin contracts a spring from the hole while contracting a spring. Retreats to the unlocked state. The variable valve gear includes a hydraulic control circuit (second control circuit) including the second control valve and including an unlocking oil passage communicating the second control valve with the unlocking chamber. Is done.
[0004]
[Patent Document 1]
JP-A-2002-309974 (FIG. 3)
[0005]
[Problems to be solved by the invention]
By the way, in the variable phase mechanism having the lock pin mechanism as described above, in addition to the oil passage for lubricating the bearing of the camshaft, the oil passage for the first control circuit communicating with the advance hydraulic chamber and the retard hydraulic chamber. In addition, at least an oil passage or the like of the second control circuit leading to the lock release chamber of the lock pin mechanism is required. In general, these oil passages have a portion extending in the axial direction independently of the inside of the camshaft, and a circumferential portion of a bearing portion on the side of the phase variable mechanism of the camshaft for communicating the portion with the outside of the camshaft. And a portion opening to the surface. Therefore, openings are arranged on the peripheral surface by a predetermined interval in the axial direction by the number of the oil passages. As a result, the cam cap constituting the bearing surface becomes thicker in the axial direction, and the engine is compact. Is inhibited.
[0006]
In order to cope with this problem, for example, of the above oil passages, the oil passage for lubrication and the oil passage for unlocking the second control circuit are shared, and the number of oil passages opened on the peripheral surface of the camshaft is reduced. It can be reduced. However, in that case, it is important how much hydraulic pressure should be supplied to the common oil passage. In other words, during operation of the engine, it is necessary to always supply a relatively high oil pressure to the lubricating oil passage to avoid seizure of the shaft, whereas the unlocking oil passage is particularly required to complete the engine starting operation. If an excessively high oil pressure is supplied before the explosion, the lock pin is disengaged, generating vibrations and abnormal noise due to the rattling of the rotor, and the combustion of the engine becomes unstable.
[0007]
In view of the above, the present invention provides a compact cam cap by sharing a cam journal lubricating oil passage and a lock pin releasing oil passage, and provides an engine having both engine starting stability and lubricating performance. An object is to provide a variable valve device.
[0008]
[Means for Solving the Problems]
In order to solve the above-mentioned problems, the present invention is characterized in that it is configured as follows. First, the invention according to claim 1 of the present application has a hydraulic phase variable mechanism provided at an end of a camshaft to vary the phase of the camshaft with respect to a crankshaft, and further advances to the phase variable mechanism. A lock pin mechanism that connects a camshaft-side rotating member and a crankshaft-side rotating member that form the angle hydraulic chamber and the retard hydraulic chamber; and operates on the advance hydraulic chamber and the retard hydraulic chamber. An engine provided with a first control circuit including a first control valve for supplying and discharging oil, and a second control circuit including a second control valve for supplying and discharging hydraulic oil to and from a lock release chamber of the lock pin mechanism. Wherein the first control circuit and the second control circuit each have an oil passage that opens in the circumferential surface of the bearing portion of the camshaft at an interval in the axial direction and extends inside the camshaft in the axial direction, respectively. An oil passage inside the camshaft of the second control circuit branches off and communicates with a bearing lubrication oil passage also provided inside the camshaft, and opens and closes and opens the second control valve. Control means for controlling the degree is provided, and the control means controls the opening degree of the second control valve to a throttle state at least until a complete explosion occurs when the engine is started.
[0009]
According to the present invention, since the oil passage inside the camshaft of the second control circuit branches off and communicates with the bearing lubrication oil passage also formed inside the camshaft, these oil passages are shared. Thus, the number of oil passages opened on the peripheral surface of the camshaft can be reduced. Therefore, the cam cap constituting the bearing surface of the camshaft is prevented from becoming thick in the axial direction, and compactness is not hindered.
[0010]
By controlling the opening of the second control valve to be in a throttled state at least until a complete explosion occurs at the time of engine start, hydraulic pressure is supplied to the common oil passage, but an excessively high oil passage is supplied. Not done. This prevents the lock pin from being accidentally pulled out before the complete explosion, and achieves good starting stability of the engine and generation of abnormal noise due to rattling of the rotor.
[0011]
On the other hand, since a certain amount of hydraulic pressure is supplied to the lubricating oil passage, problems such as seizure of the shaft are avoided. In addition, since the rotation speed is low at the time of starting, it is not necessary to supply a large amount of lubricating oil, and a sufficient amount of lubricating oil is supplied to the bearing even with a hydraulic pressure that is not too high.
[0012]
Next, according to a second aspect of the present invention, in the variable valve operating device for an engine according to the first aspect, the control means includes a hydraulic pressure that lubricates the bearing without unlocking the lock pin mechanism. The second control valve is controlled so as to be supplied to an oil passage inside the camshaft of the second control circuit.
[0013]
ADVANTAGE OF THE INVENTION According to this invention, ensuring both the startability of an engine and the favorable lubrication performance is achieved reliably.
[0014]
Next, according to a third aspect of the present invention, in the variable valve operating device for an engine according to the first or second aspect, the lock pin mechanism is configured to move the camshaft-side rotating member relative to the crankshaft-side rotating member. It is characterized in that both members are connected at an intermediate position in the rotation range.
[0015]
According to the present invention, the lock pin mechanism couples the camshaft-side rotation member and the crankshaft-side rotation member at an intermediate position between the relative rotation ranges. Therefore, in the phase variable mechanism including the lock pin mechanism, There is an advantage that the phase variable control can be performed widely and finely in both directions from this coupling position. However, if the lock pin comes off before the complete explosion occurs, it becomes difficult to maintain the intermediate position in such an intermediate position lock variable phase mechanism, the valve timing changes, and especially the combustion characteristics of the engine become unstable. Therefore, when the invention according to claim 1 or 2 is applied to such a phase variable mechanism of the intermediate position lock, a particularly effective operation and effect can be obtained.
[0016]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, embodiments of the present invention will be described. As shown in FIG. 1, an engine 1 according to the present embodiment is disposed parallel to a crankshaft (denoted by reference numeral 2) and rotatably supported by a cylinder head 3 and a cam cap 4. , An intake camshaft 5 and an exhaust camshaft 6. Sprockets 7, 8 which can rotate relative to the camshafts 5, 6 within a predetermined range are fitted in the vicinity of one ends of the camshafts 5, 6, and the sprockets 7, 8 and the crank A chain 9 is wound around the sprocket on the shaft 2 side. Then, with the rotation of the crankshaft 2, the two sprockets 7, 8 and the two camshafts 5, 6 rotate via the chain 9, whereby a plurality of cams fixed to the camshafts 5, 6 are provided. A plurality of intake valves 12 ... 12 and exhaust valves 13 ... 13 are opened and closed via 10 ... 10, 11 ... 11. A front cover 14 that covers the end faces of the cylinder block and the cylinder head 3 (not shown) on the cam cap 4 side is attached.
[0017]
The variable valve operating device 20 of the engine 1 is provided at each end of the intake camshaft 5 and the exhaust camshaft 6 on the sprocket 7, 8 side, and the rotational phase angle of these camshafts 5, 6 with respect to the crankshaft 2 ( That is, the intake-side and exhaust-side hydraulic phase variable mechanisms 21 and 22 for independently changing the opening and closing timings of the intake valves 12... 12 and the exhaust valves 13. The intake and exhaust hydraulic control valves (first control valves) 23 for controlling the hydraulic pressure supplied to the advance hydraulic chambers 38 and 38 and the retard hydraulic chambers 39 and 39 (see FIG. 3) 24. The two phase variable mechanisms 21 and 22 are controlled independently of each other and individually according to the operating state of the engine 1. Since the two phase variable mechanisms 21 and 22 have substantially the same structure, the structure of the variable phase mechanism for exhaust 22 will be described below as an example, and the structure of the variable phase mechanism for intake 21 will be described below. Is omitted.
[0018]
That is, as shown in FIGS. 2 and 3, the phase variable mechanism 22 includes a hollow housing 31 having a plurality of protrusions 30... 30 (only two are shown in FIG. 31 is a basic structure in which the housing 31 and the lid member 32 are integrally fixed to the sprocket 8 by a plurality of bolts 33. In addition, the variable phase mechanism 22 includes a plurality of (more specifically, the same number as the protruding portions 30 of the housing 31) engaging portions 37... 37 (one in FIG. (Shown only) and a receiving member 36 fitted to the center of the rotor 35, and the rotor 35 and the receiving member 36 are connected to the exhaust camshaft 6 by a single bolt 34 at the center. It is a structure fixed integrally to the 37 define a space surrounded by the sprocket 8, the housing 31, the lid member 32, and the rotor 35 into hydraulic chambers 38 for advance and hydraulic chambers 39 for retard. I do.
[0019]
The receiving member 36 has a tool spring 40 therein. One end 41 of the torsion spring 40 is locked by a pin 42 erected on the lid member 32, and the other end 43 is locked by a concave portion provided in a central boss portion of the receiving member 36. Thus, the spring 40 biases the exhaust camshaft 6 in the advance direction (X direction in FIG. 3). As a result, a one-sided force in the retard direction (direction in which the overlap increases) of the exhaust camshaft 6 due to the reaction force of the return spring (not shown) that constantly biases the exhaust valves 13. Offset. In addition, the intake side lug spring 40 urges the intake camshaft 5 in the advance direction (X direction in FIG. 3). This cancels out the unidirectional urging force of the intake camshaft 5 in the retard direction (direction in which the overlap decreases) due to the reaction force of the return spring that urges the intake valves 12.
[0020]
Further, the phase variable mechanism 22 has a lock pin mechanism 50 mounted thereon, as clearly shown in FIG. The lock pin mechanism 50 includes a lock pin 51 that can move in the axial direction within one predetermined engagement portion 37 of the rotor 35. The lock pin 51 is constantly urged toward the sprocket 8 by the return spring 52. When the camshaft 6 and the rotor 35 reach an intermediate position in the relative rotation range, the sprocket 8 has a recess 53 into which the lock pin 51 is fitted. Further, the recess 53 is provided with a lock pin releasing hydraulic chamber 54 communicating with an unlocking oil passage 105 described later.
[0021]
Next, the first control valves 23 and 24 will be described. As shown in FIG. 4, the first control valve 24 for exhaust is inserted into the insertion hole 60 so that the axial direction extends vertically, and is assembled to the cam cap 4 using a bracket 61 and a bolt 62. The first control valve 24 has a hollow valve case 63, a spool 64 movable in the case 63 in the axial direction, and a spring 65 for urging the spool 64 in one direction. The amount of movement of the spool 64 in the axial direction is adjusted by an actuator whose driving is controlled by the control unit 113 (see FIG. 7), for example, an electromagnetic solenoid. The first control valve 24 is provided with one input port 70, two drain ports 71 and 72, an advance output port 73, and a retard output port 74. An oil supply oil passage 80 (see FIG. 5) is connected to the input port 70, and an advance oil passage 81 and a retard oil passage 82 are connected to the advance output port 73 and the retard output port 74, respectively. Have been.
[0022]
On the other hand, as shown in FIG. 1, the first control valve 23 on the intake side is mounted on the front cover 14 in a horizontal direction, and its structure is the same as that of the first control valve 24 for exhaust. Detailed description is omitted. The control by the first control valves 23 and 24 controls the degree of communication with the input port 70 and the drain ports 71 and 72 of the advance oil passage 81 and the retard oil passage 82 according to the position of the spool 64 in the axial direction. Is to control the advance hydraulic pressure and the retard hydraulic pressure supplied to the advance hydraulic chamber 38 and the retard hydraulic chamber 39, respectively.
[0023]
Next, the exhaust-side advance oil passage 81 and the retard oil passage 82 will be described. The advance oil passage 81 includes a horizontal oil passage 83 formed at a high position of the cam cap 4 shown in FIG. 5, an internal oil passage 84 also formed on the cam cap 4, and an exhaust camshaft 6 shown in FIG. And an annular groove 93 formed in the bearing surface 91.
[0024]
As shown in FIG. 4, one end of the horizontal oil passage 83 is connected to the first exhaust control valve 24 and connected to the advance output port 73. The other end of the horizontal oil passage 83 communicates with the upper end of an internal oil passage 84 shown in FIG. 5, and the lower end of the internal oil passage 84 is connected to an annular groove 93 shown in FIG.
[0025]
Next, the retard oil passage 82 includes a horizontal oil passage 85 formed at a lower position of the cam cap 4 shown in FIG. 5, an internal oil passage 86 also formed in the cam cap 4, and an exhaust gas shown in FIG. An annular groove 94 formed in the bearing surface 91 for the camshaft 6.
[0026]
As shown in FIG. 4, one end of the horizontal oil passage 85 is connected to the first exhaust control valve 24 and is connected to the retard output port 74. The other end of the horizontal oil passage 85 communicates with the upper end of an internal oil passage 86 shown in FIG. 5, and the lower end of the internal oil passage 86 is connected to an annular groove 94 shown in FIG.
[0027]
As shown in FIG. 5, the hydraulic supply oil passage 80, the advance oil passage 81, and the retard oil passage 82 are formed by exposing at the end surface of the cam cap 4 (lateral oil passages 83, 85, etc.). ). Therefore, as shown in FIG. 1, the cover 87 is fastened to the end face of the cam cap 4 to complete the oil passage on the end face of the cam cap 4.
[0028]
As shown in FIG. 2, on the peripheral surface of the exhaust camshaft 6, there are formed vertical oil passages 95 and 96 facing the annular grooves 93 and 94, respectively. Thus, the horizontal oil passages 97 and 98 communicate with the retard hydraulic chambers 38... 38 and the advance hydraulic chambers 39.
[0029]
As described above, the exhaust-side advance oil passage 81 and the retard oil passage 82 include the horizontal oil passages 83 and 85, the internal oil passages 84 and 86, the annular grooves 93 and 94, the vertical oil passages 95 and 96, and the horizontal oil passages 95 and 96. Oil passages 97 and 98 are included.
[0030]
On the other hand, the intake-side advance oil passage 100 and the retard-side oil passage 101 (see FIG. 6) are provided with an intake first control valve 23 attached to the front cover 14 as shown in FIG. The advance hydraulic chambers 38 ... 38 and the retard hydraulic chambers 39 ... 39 of the variable mechanism 24 communicate with each other. The advance oil passage 100 and the retard oil passage 101 partially have an oil passage (not shown) provided from the intake first control valve 23 to the front cover 14. The oil passage (parts of the advance oil passage 100 and the retard oil passage 101 shown in FIG. 6) shown in FIG. 6 is provided through an oil passage (not shown) provided inside the cylinder head 3 in this oil passage. It communicates with the angular annular groove 102 and the retard angular annular groove 103, respectively. However, the advance oil passage 100 includes a groove oil passage 104 provided on the bottom surface of the cam cap 4. 2, on the peripheral surface of the intake camshaft 5, vertical oil passages 95 and 96 facing the annular grooves 103 and 102 are provided, and through the vertical oil passages 95 and 96. The horizontal oil passages 97 and 98 are guided to the advance hydraulic chambers 38 and 38 and the retard hydraulic chambers 39 and 39 of the intake variable phase mechanism 21.
[0031]
As described above, the intake-side advance oil passage 100 and the retard oil passage 101 include the oil passages provided in the front cover 14 and the cylinder head 3, the annular grooves 102 and 103, the groove oil passage 104, and the vertical oil passage. 95, 96 and horizontal oil passages 97, 98.
[0032]
Here, a first control circuit 90 (see FIG. 7) is constituted by the intake-side and exhaust-side advance oil passages 81 and 100 and the retard oil passages 82 and 101, the first control valves 23 and 24, and the like. .
[0033]
Next, the unlocking oil passage 105 leading to the lock pin mechanism 50 provided in the exhaust-side variable phase mechanism 22 will be described with reference to FIG. Note that the intake side has substantially the same configuration, and a description thereof will be omitted.
[0034]
That is, a hydraulic control valve (second control valve) 120 (see FIG. 7) for supplying and discharging hydraulic oil to and from the lock release chamber 54 of the lock pin mechanism 50 is provided in, for example, the cylinder head 3. A control oil passage 121 extending from 120 communicates with the camshaft bearing 92 on the cylinder head 3 side shown in FIG. The control oil passage 121 communicates with a lock pin annular groove 122 provided in the exhaust camshaft 6. A vertical oil passage 123 provided inside the camshaft 6 from the lock pin annular groove 122 is connected to a horizontal oil passage 125. The horizontal oil passage 125 penetrates an end of the exhaust camshaft 6 on the side of the phase variable mechanism 22 and communicates with an annular groove 127 provided on the surface of the sprocket 8 via a groove 126 provided on the rotor 35. . An oil passage 128 in the sprocket is provided from the annular groove 127 to the inside of the sprocket 8 and to the unlocking chamber 54.
[0035]
As described above, the unlocking oil passage 105 includes the control oil passage 121, the annular groove 122, the vertical oil passage 123, the horizontal oil passage 125, the groove 126, the 127 annular groove, and the oil passage 128 in the sprocket.
[0036]
Here, a second control circuit 110 (see FIG. 7) is configured by the unlocking oil passages 105, 105 on the intake side and the exhaust side, the second control valve 120, and the like.
[0037]
The oil passages (vertical oil passages 123, 123) inside the camshafts 5, 6 of the second control circuit 110 are connected to bearing lubrication oil passages 124, 124 also provided inside the camshafts 5, 6. Branch and communicate
As shown in FIGS. 1 and 6, the cam cap 4 is fastened to the ends of the cylinder head 3 on the side of the phase variable mechanisms 21 and 22 by bolts 130. FIG. 6 shows through holes 131... 131 of the bolts 130.
[0038]
Next, the operation and effect of the present embodiment will be described. First, the operation of the phase variable mechanisms 21 and 22 will be described. As shown on the exhaust side in FIG. 3, the rotor 35 moves the sprocket 8 (the same applies to the intake side sprocket 7), the housing 31, and the lid member 32. Until the engaging portions 37... 37 come into contact with the protruding portions 30. This makes it possible to change the rotational phase angle of the camshaft 6 (same for the intake camshaft 5) with respect to the sprocket 8 (same) and, thus, the crankshaft 2, and to open and close the intake and exhaust valves 12,. The time can be changed.
[0039]
The supply / discharge control of the first control valves 23 and 24 is performed based on the operating state of the engine 1 detected by various sensors such as an engine speed sensor, a throttle opening sensor, and a water temperature sensor. Is performed by the control unit 113 (see FIG. 7) to optimize the output performance of the engine 1 and the like.
[0040]
For example, when the engine is idling, the amount of intake air is small, and if the overlap between the intake valves 12... 12 and the exhaust valves 13. In such a case, the overlap is reduced to suppress the mixing of the combustion gas, thereby stabilizing the combustion. On the other hand, at low / medium loads, the overlap is increased while increasing the intake air amount, the internal EGR is also increased, and the fuel efficiency is improved while maintaining the output.
[0041]
For example, when the exhaust camshaft 6 is shifted from the retarded state to the advanced state by the advance oil passage 81 and the retard oil passage 82 of the first control circuit 90, the exhaust hydraulic control shown in FIG. The spool 64 of the valve 24 moves in the axial direction. As a result, the degree of communication of the advance output port 73 with the input port 70 increases, and conversely, the degree of communication with the drain port 71 decreases. Therefore, the advance hydraulic pressure output from the advance output port 73 to the advance oil passage 81 increases. On the other hand, the degree of communication of the retard output port 74 with the input port 70 decreases, and the degree of communication with the drain port 72 increases. Therefore, the retard hydraulic pressure output from the retard output port 74 to the retard oil passage 82 decreases. Accordingly, the oil pressure in the advance hydraulic chambers 38... 38 of the variable exhaust phase mechanism 22 shown in FIG. The shaft 6 is displaced to the advance side with respect to the housing 31 or the crankshaft 2. The shift from the advanced state to the retarded state can be achieved by moving the spool 64 in the opposite direction to the case of shifting from the retarded state to the advanced state.
[0042]
Next, the second control circuit 110 will be described with reference to FIG. 7. The operating pressure discharged from the oil pump 111 passes through the original pressure oil passage 112 and the second hydraulic supply oil passage 114 to the second control valve 120. Supplied to The second control valve 120 is a duty solenoid valve, and controls the oil in accordance with the duty ratio (the ON time ratio in one ON-OFF cycle) of the control signal applied by the control unit (corresponding to the control means in the claims) 113. The opening and closing and opening of the paths 114 and 112 are adjusted to control the hydraulic pressure.
[0043]
Then, the hydraulic oil controlled by the second control valve 120 is supplied to the control oil passage 121 shown in FIG. The hydraulic oil supplied to the control oil passage 121 is supplied to the lock pin annular groove 122. A vertical oil passage 123 provided inside the camshaft 6 from the lock pin annular groove 122 branches into a bearing lubrication oil passage 124 and a horizontal oil passage 125. The hydraulic oil supplied to the bearing lubrication oil passage 124 lubricates a large number of bearings 91, 92,. On the other hand, the hydraulic oil supplied to the horizontal oil passage 125 is supplied to a groove 126 provided in the rotor 35, and further provided in an annular groove 127 provided in the surface of the sprocket 8 which rotates relatively and inside the sprocket 8. The oil is supplied to the lock release chamber 54 through the oil passage 128 in the sprocket. As a result, the lock pin 51 urged toward the sprocket 8 by the spring 52 comes out of the recess 53 by operating pressure, and the lock mechanism 53 is released.
[0044]
At this time, the oil passages provided on the cam cap 4 and the bearing surfaces 91, 92 of the cylinder head 3 are originally formed by the advance oil passages 81, 100 and the retard oil passages 82, 101 of the first control circuit 90. The oil passage 105 for unlocking the second control circuit 110 and the oil passage 124 for lubricating the bearing portion are required at least. However, in the vertical oil passage 123, the oil passage (lateral oil passage 125) for releasing the lock pin is branched and provided to the bearing lubrication oil passage 124, so that the oil passage is shared and provided on the cam cap 4. The number of annular grooves can be reduced. As a result, the cam cap 4 forming the bearing surface 91 of the camshaft 6 can be made compact in the axial direction.
[0045]
Next, valve opening control by the control unit 113 of the second control valve 120 will be described with reference to FIG. 8. The lowermost curve is used to lubricate the bearings 91 and 92 of the camshaft 6 with respect to the water temperature. 2 shows a line (lubrication line) of the valve opening of the second control valve 120 that supplies a necessary operating pressure to the second control valve 120. This lubricating line has the characteristic that the valve opening is opened as the water temperature rises and the operating pressure is kept constant. That is, when the water temperature is low, the viscosity of the hydraulic oil is high, so that the amount of the hydraulic oil leaking from the connection points of the respective oil passages is small. As a result, the operating pressure tends to rise, so that the valve opening is kept in the throttled state. On the other hand, when the water temperature rises, the amount of hydraulic oil leaking from the connection points increases, so that it is necessary to open the valve to maintain a constant operating pressure. The area below the lubrication line is a valve opening degree control area to which the operating pressure is supplied to such an extent that the lock pin 51 does not come off and is not lubricated.
[0046]
A curve drawn above the lubrication line represents a line (an unlocking line) of the valve opening of the second control valve 120 that supplies an operating pressure for releasing the lock pin 51 with respect to the water temperature. Similarly to the lubrication line, when the water temperature is low, the lock release line performs throttle control of the valve opening, performs control to open the valve as the water temperature rises, and keeps the operating pressure constant. The area between the lubrication line and the lock release line is a valve opening degree control area to which the lubrication is performed, but the operating pressure of which the lock pin 51 does not come off is supplied (corresponding to claim 2).
[0047]
Next, the control of the phase variable mechanism 22 by the water temperature and the engine rotation will be described with reference to FIG. 9. The hatched portion in the figure is the phase variable mechanism control area, and the curve drawn below the phase variable mechanism control area is the lock. The line for releasing the pin 51 is shown. When the water temperature is lower than the predetermined water temperature Temp1, the lock pin 51 is not released regardless of the rotation of the engine 1 in the fast idle state. The area below the lock pin 51 release line is an idle rotation area, and the lock pin 51 is not released. For example, consider the case where the lock pin 51 is released at the water temperature Temp2. When the control signal for releasing the lock pin 51 is received at Temp2 in FIG. 9, the control for fully opening the valve opening is performed as shown in FIG. That is, the operating pressure (α) controlled in the region between the lubrication line and the lock pin release line at least until the complete explosion exceeds the lock pin release line by the lock pin 51 release signal, and the valve is fully opened. Is controlled. Of course, the valve opening (β) may slightly exceed the lock pin release line. In short, what is necessary is just to shift from the area between the lubrication and the lock release line to the area beyond the lock release line.
[0048]
By performing such control, by controlling the opening degree of the second control valve 120 to a throttled state until the complete explosion at the start of the engine 1, an excessively high hydraulic pressure is applied to the common oil passage 123. Not supplied. This prevents the lock pin 51 from accidentally coming off at least before the complete explosion, and achieves good starting stability of the engine 1 and generation of abnormal noise due to rattling of the rotor 35.
[0049]
On the other hand, since a certain level of operating pressure is supplied to the lubricating oil passage 124, problems such as seizure of the shafts 5 and 6 are also avoided. In addition, since the rotation speed is low at the time of starting, it is not necessary to supply a large amount of lubricating oil, and a sufficient amount of lubricating oil is supplied to the bearing portions 91 and 92 even with a not so high hydraulic pressure.
[0050]
As described above, the control unit 113 controls the release of the lock pin 51 in accordance with the water temperature and the engine rotation, and supplies the operating pressure for lubricating without releasing the lock pin 51 when the lock pin 51 is not released. Such control is performed.
[0051]
When the key is turned off, the second control valve 120 is fully opened, and when the key is turned on, the opening of the control valve 120 is reduced, and a predetermined operating pressure is supplied. Thereby, fail-safe lubrication at the time of disconnection or the like can be ensured.
[0052]
Further, since the lock pin mechanism 50 of the present embodiment couples the rotor 35 and the sprocket 8 at an intermediate position of the relative rotation range, in the phase variable mechanisms 21 and 22 including the lock pin mechanism 50, In addition, there is an advantage that the phase variable control can be performed widely and finely in both directions. However, since it is necessary to provide the lug springs 40 on both the intake side and the exhaust side, if the lock pin 51 comes off before the complete explosion, it becomes difficult to maintain the intermediate position, the valve timing changes, and especially the engine timing is changed. 1 becomes unstable in flammability. Therefore, a particularly effective operation and effect can be obtained by applying the above-described control in which the opening of the second control valve 120 is kept in the throttled state until the complete explosion, and only the lubrication of the bearing portions 91 and 92 is applied.
[0053]
【The invention's effect】
As described above, according to the present invention, the oil passage inside the camshaft of the second control circuit branches off and communicates with the bearing lubrication oil passage also formed inside the camshaft. The oil passage is shared, and the number of oil passages opened on the peripheral surface of the camshaft can be reduced. Therefore, the cam cap constituting the bearing surface of the camshaft is prevented from becoming thick in the axial direction, and compactness is not hindered.
[0054]
By controlling the opening of the second control valve to be in a throttled state at least until a complete explosion occurs at the time of engine start, hydraulic pressure is supplied to the common oil passage, but an excessively high oil passage is supplied. Not done. This prevents the lock pin from being accidentally pulled out before the complete explosion, and achieves good starting stability of the engine and generation of abnormal noise due to rattling of the rotor.
[0055]
On the other hand, since a certain amount of hydraulic pressure is supplied to the lubricating oil passage, problems such as seizure of the shaft are avoided. In addition, since the rotation speed is low at the time of starting, it is not necessary to supply a large amount of lubricating oil, and a sufficient amount of lubricating oil is supplied to the bearing even with a hydraulic pressure that is not too high.
[Brief description of the drawings]
FIG. 1 is a plan view showing a variable phase mechanism of an engine according to an embodiment of the present invention.
FIG. 2 is an enlarged side view of a partly cutaway showing a periphery of a hydraulic variable phase mechanism.
FIG. 3 is a partially cutaway front view of the variable phase mechanism.
FIG. 4 is a partially cutaway front view of the first exhaust control valve.
FIG. 5 is a front view of the cam cap.
FIG. 6 is a bottom view of the cam cap.
FIG. 7 is a hydraulic circuit diagram of the variable phase mechanism and the lock pin mechanism in the present embodiment.
FIG. 8 is a map of an operating pressure according to a water temperature and a valve opening of a second control valve.
FIG. 9 is a map of lock pin release control according to the water temperature of the second control valve and the engine speed.
[Explanation of symbols]
1 engine
2 Crankshaft
5 Intake camshaft
6 Exhaust camshaft
20 Variable valve gear
38 Hydraulic chamber for advance
39 Hydraulic chamber for retard angle
50 Lock pin mechanism
54 Lock release room
21,22 Variable phase mechanism
23, 24 First control valve
81,100 oil passage for advance angle
82,101 Oil passage for retard angle
90 1st control circuit
91,92 Bearing surface
93 (81), 102 (100) annular groove (oil passage for retard angle)
94 (82), 103 (101) annular groove (advance oil passage)
105 Lock pin release oil passage
110 second control circuit
113 control unit (control means)
120 Second control valve
124 Bearing lubrication oil passage

Claims (3)

A hydraulic phase variable mechanism is provided at an end of the camshaft to vary the phase of the camshaft with respect to the crankshaft, and an advanced hydraulic chamber and a retard hydraulic chamber are formed in the variable phase mechanism. A lock pin mechanism for connecting the camshaft-side rotating member and the crankshaft-side rotating member is provided, and a first control valve including a first control valve for supplying and discharging hydraulic oil to and from the advance hydraulic chamber and the retard hydraulic chamber. A variable valve train for an engine, comprising: a first control circuit; and a second control circuit including a second control valve for supplying and discharging hydraulic oil to and from a lock release chamber of the lock pin mechanism. The circuit and the second control circuit include oil passages that are opened at intervals in the axial direction on the peripheral surface of the bearing portion of the camshaft and that extend in the camshaft in the axial direction, respectively. An oil passage inside the shaft branches off and communicates with a bearing lubrication oil passage also provided inside the camshaft, and a control means for controlling the opening / closing and opening of the second control valve is provided. The variable valve actuation device for an engine, wherein the control means controls the opening of the second control valve to a throttled state at least until a complete explosion occurs when the engine is started. The control means controls the second control valve such that hydraulic pressure such that the bearing portion is lubricated without the lock pin mechanism being unlocked is supplied to the camshaft internal oil passage of the second control circuit. The variable valve train for an engine according to claim 1. 3. The variable valve actuation valve for an engine according to claim 1, wherein the lock pin mechanism couples both members at an intermediate position in a relative rotation range between the camshaft-side rotating member and the crankshaft-side rotating member. apparatus.

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