JPH11241607A - Variable valve mechanism - Google Patents

Abstract

(57) [Problem] To provide a cam phase variable device having a lock mechanism for locking a vane rotor rotatable relative to a vane housing at a retard position, and to integrate most of the unlocking hydraulic supply path into one system. To make the equipment more compact. When pressure oil is supplied to a retard side oil chamber, a valve piston (90) moves toward a housing end wall (34) in a valve piston hole (44b), and a retard side oil chamber and a valve piston hole. Communicates with When supplying the pressurized oil to the advance side oil chamber, the valve piston moves in the opposite direction, and the advance side oil chamber communicates with the valve piston hole. In each case, the valve piston bore and vane (44) and lock pin (70)
Pressure oil flows into the lock hole (22b) through the oil passages (44e, 72, 73) formed in the lock hole, and separates the lock pin from the lock hole against the spring force of the spring (80).

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a variable valve mechanism for variably adjusting the rotational phase of a camshaft relative to a rotation transmitting member rotatable synchronously with a crankshaft of an internal combustion engine by hydraulic pressure, and more particularly to a vane using a spring force of a spring. The present invention relates to a vane type variable cam phase device that locks a member and releases the lock in response to supply of pressure oil to a retard side or advance side oil chamber.

[0002]

2. Related Background Art A hydraulic vane type cam phase changing device has a housing member rotatable integrally with a rotation transmitting member that rotates synchronously with a crankshaft, and a vane housed in the housing member. A possible vane member, and a cam phase is changed by supplying and discharging pressure oil to and from an oil chamber formed between the vane and the housing member, thereby changing a valve overlap period between the intake valve and the exhaust valve. It is variably adjusted and contributes to the improvement of engine startability and engine output. The hydraulic vane type cam phase variable device has an advantage that it can be manufactured relatively inexpensively, but has a disadvantage that the cam phase fluctuates when the engine is started.

That is, when the supply of pressurized oil to the oil chamber of the variable cam phase device is stopped due to the stoppage of the operation of the engine, the pressurized oil in the oil chamber located at the upper part of the engine escapes into the cylinder head, and the vane through the pressurized oil The connection between the and the receiving member is released, and the vane can freely rotate in the receiving member. During engine start in such a state, during the period from opening of the intake valve or exhaust valve to the maximum lift, a negative driving torque that suppresses cam rotation is applied to the camshaft via the cam, and from the maximum lift to the valve closing. During this period, a positive drive torque that promotes cam rotation is applied to the camshaft. As a result, the vane that is not restricted by the pressure oil moves in the housing member, the cam phase fluctuates, and misfiring easily occurs.

In order to prevent the cam phase shift due to the driving torque described above, the valve timing adjusting device described in Japanese Patent Application Laid-Open No. 9-60508 has the vane rotor 9 (the reference numeral is the one described in the official gazette) being the latest. It has a lock mechanism that locks at a corner position. Vane 9 of vane rotor 9
Reference numerals a and 9b are accommodated in a fan-shaped space formed by the shoes 3a and 3b of the shoe housing 3 constituting a housing member together with the chain sprocket 1 and the front plate 4.

The lock mechanism includes a stopper piston 7 having a large-diameter portion accommodated in an accommodation hole 8 formed in the vanes 9a and 9b and a small-diameter portion fitted in a stopper hole 20 formed in the front plate 4; A spring 18 disposed in the receiving hole to bias the piston 7 toward the front plate;
A guide ring 19 is provided between the small diameter portion of the piston and the inner wall of the vane in the accommodation hole. A hydraulic chamber 23 communicating with the retard hydraulic chamber is formed in the vane rotor between the guide ring and the large-diameter portion of the piston, and a hydraulic pressure communicating with the advanced hydraulic chamber is formed in the front plate between the stopper hole and the small-diameter portion of the piston. A chamber 24 is formed. And
When pressure oil is not supplied to the hydraulic chambers 23 and 24 and the vane is at the most retarded position, the piston 7 is fitted into the stopper hole 20 by the urging force of the spring 18, while hydraulic oil is supplied to either of the hydraulic chambers. When supplied, the piston comes off the stopper hole and the lock is released.

[0006]

The above-described valve timing adjusting device can prevent the phase shift due to the driving torque applied to the camshaft. However, in addition to the locking spring, there are two hydraulic chambers for unlocking, 2 to both hydraulic chambers
It is necessary to provide a guide ring for separating the pressure oil supply system of the system and the two hydraulic chambers, and the device becomes large.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a variable valve mechanism in which a lock mechanism for preventing a cam phase shift while the engine is stopped is made compact to reduce the size and weight.

[0008]

SUMMARY OF THE INVENTION A variable valve mechanism according to the present invention comprises a housing member rotatable integrally with a rotation transmitting member that rotates synchronously with a crankshaft of an internal combustion engine, and a housing member rotatable integrally with a camshaft. A vane member rotatable with respect to the vane member, and a lock mechanism for urging the movable body disposed in the vane member by urging means to fit the movable body into a lock hole of the housing member, and the retard-side oil chamber The hydraulic pressure is guided to the lock hole at the time of supplying the hydraulic pressure to the lock chamber and the hydraulic pressure to the advance side oil chamber, and the movable body is detached from the lock hole.

In the variable valve mechanism having the above structure, when the vane member relatively rotates and the movable body is aligned with the lock hole, if there is no hydraulic pressure supply to the retard side or advance side oil chamber, the urging means is provided. The movable body is fitted into the lock hole by the force and the vane member is locked. On the other hand, when hydraulic pressure is supplied to the retard side or the advance side oil chamber, in either case, hydraulic pressure is introduced into the lock hole and the movable body is urged to the opposite lock hole side, and the movable body is locked in the lock hole. To release the lock. Like this
In the variable valve mechanism according to the present invention, the hydraulic pressure from the retard-side oil chamber and the hydraulic pressure from the advance-side oil chamber are caused to act as lock release hydraulic pressures on the same portion called a lock hole. For this reason, most of the lock release hydraulic supply path is integrated into one system, the lock mechanism is compact, and the variable valve mechanism is reduced in size and weight. Even if oil escapes from the retard-side oil chamber and the advance-side oil chamber during operation stop of the internal combustion engine, a cam phase shift occurs because the lock state is maintained by the urging force of the urging means. Therefore, the occurrence of misfire at the next start of the internal combustion engine is prevented.

In the present invention, preferably, the movable body is
The lock pin comprises a cylindrical lock pin slidably disposed in a lock pin hole formed in the vane portion. According to this preferred embodiment,
The lock pin hole and the lock hole may be formed in a cylindrical shape that fits the lock pin, and the shape of the lock pin, the lock pin hole and the lock hole becomes simple, and the processing can be performed easily and accurately. Further, oil leakage from the sliding surface between the lock pin and the lock pin hole is reduced, and the sliding motion of the lock pin in the lock pin hole, that is, the locking operation and the unlocking operation are performed quickly. Further, the deterioration of the rotational balance of the vane member and the housing member due to the arrangement of the lock pin and the formation of the lock pin hole and the lock hole is prevented or suppressed.

In the present invention, preferably, the hydraulic pressure from the advance side or the retard side oil chamber is selectively supplied to the lock hole in accordance with the supply of the hydraulic pressure to the advance side oil chamber and the supply of the hydraulic pressure to the retard side oil chamber. There is provided a switching valve to be introduced into the air conditioner. According to this preferred embodiment,
The hydraulic pressure can be introduced into the lock hole, that is, the lock can be released accurately. More preferably, the switching valve has a valve piston housed in a valve piston hole formed in the vane portion. The valve piston hole communicates with the lock hole via an oil passage for unlocking hydraulic pressure formed in each of the vane portion and the movable body, and can communicate with the advance-side oil chamber and the retard-side oil chamber. . When hydraulic pressure is supplied to the advance-side oil chamber, the valve piston connects the advance-side oil chamber and the valve piston hole, and cuts off the communication between the retard-side oil chamber and the valve piston hole. When hydraulic pressure is supplied to the retard-side oil chamber, the valve piston connects the retard-side oil chamber to the valve piston hole and cuts off the communication between the advance-side oil chamber and the valve piston hole.

According to this preferred aspect, the switching valve can be provided in the vane portion. The unlocking hydraulic supply path from the valve piston hole to the lock hole is shared by the hydraulic supply from the advance oil chamber to the lock hole and the hydraulic supply from the retard oil chamber to the lock hole. Most of the supply routes are combined into one system. More preferably, the valve piston comprises a cylindrical pin. According to this preferred embodiment, machining of the valve piston and the valve piston hole can be performed simply and accurately. Further, oil leakage from between the sliding surfaces between the valve piston and the valve piston hole is reduced, and the sliding movement of the valve piston in the valve piston hole, that is, the hydraulic pressure selecting operation is performed quickly. Further, the deterioration of the rotational balance of the vane member due to the arrangement of the valve piston and the formation of the valve piston hole is prevented or suppressed.

[0013] More preferably, the valve piston hole is formed through the vane portion in the axial direction of the camshaft. According to this preferred aspect, the centrifugal force due to the rotation of the variable valve mechanism about the camshaft axis acts in a direction orthogonal to the axis of the valve piston hole. It is performed accurately without being affected by. In addition, the valve piston abuts on the housing member at the movement limit position, and it is not necessary to prevent the valve piston from coming off.

[0014] Preferably, a vane seal is provided between the front end surface of the vane portion, the housing member, and the opposing surface, and an oil passage for supplying a seal hydraulic pressure that opens to the front end surface of the vane portion and the valve piston hole is provided in the vane portion. It is formed. According to this preferred aspect, when the hydraulic pressure is supplied to the advance side or the retard side oil chamber, the hydraulic pressure from the advance side or the retard side oil chamber acts on the vane seal via the oil passage for supplying the seal hydraulic pressure, and the sealing is performed. The performance is improved.

[0015] More preferably, the oil passage for supplying the seal hydraulic pressure is formed in alignment with the oil passage for supplying the unlock hydraulic pressure formed in the vane portion. According to this preferred aspect, both oil paths can be processed at once, and the processing cost can be reduced.

[0016]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, a vane type cam phase changing device as a variable valve mechanism according to an embodiment of the present invention will be described. The cam phase variable device of the present embodiment is attached to the intake camshaft of the DOHC engine and variably controls the amount of overlap of the intake valve with the exhaust valve. In the following description, the configuration on the intake valve side will be mainly described. I do. However, this device can be arranged on both the exhaust side and the intake / exhaust side of the engine.

In FIG. 1, a cam journal 15 for rotatably supporting a camshaft 10 on an intake side is provided at a joint portion between a cylinder head of a DOHC engine and a rocker cover 2 (schematically indicated by a two-dot chain line). Have been. The rocker cover 2 forms a part of the cylinder head cover. The cam 4 is formed on the camshaft 10 so as to contact the intake valve via the rocker arm.
The intake valve opens and closes with the rotation of zero.

The crankshaft (not shown) of the engine is connected to a cam pulley and a cam sprocket (rotation transmitting member 20) on the intake side via a torque transmitting element such as a belt or a chain. The torque transmitting element of the present embodiment is constituted by, for example, a toothed belt 6 (FIG. 2) made of a synthetic resin in order to reduce the weight and cost, and the rotation transmitting member 20 is constituted by a cam pulley. The cam pulley 20 has a disk-shaped main part 22, a toothed flange 24 that meshes with the toothed belt 6, and a boss part 26 that is fitted to the end of the camshaft 10. That is, the cam pulley 20
It is arranged coaxially with the camshaft 10, is rotatably supported by the camshaft 10, and rotates by receiving the torque of the crankshaft transmitted via the toothed belt 6.

The cam phase changing device of the present embodiment also intends to reduce the rotational inertia, weight and external dimensions of each part of the device and to improve the rotational balance of the device, as will be described in detail later. In connection with this, on the outer peripheral side of the cam pulley main body 22, to reduce the rotational inertia and weight of the cam pulley 20,
For example, four slots 22a (FIG. 2) are formed. In FIG. 2, reference numeral 20a indicates a mark used for positioning the rotational phase of the camshaft 10 with respect to the crankshaft.

A ring-shaped oil seal 17 for preventing oil leakage to the outside of the engine is disposed between the boss portion 26 of the cam pulley 20 and the opposing peripheral surface of the cam journal 15. The oil used for lubrication around the camshaft 10 passes through the annular space 10d (FIG. 3) defined by the camshaft 10, the cam journal 15, and the oil seal 17 and the oil passage 15c formed in the cam journal 15. Through the engine.

The cam phase changing device comprises a vane housing (accommodating member) 30 which is fixed to the outer end face of the cam pulley main body 22 by, for example, four bolts 23 (FIG. 3) and can rotate integrally with the cam pulley 20, and a bolt 14. A vane rotor (vane member) 40 fixed to the end face of the camshaft 10 and rotatable integrally with the camshaft 10 is provided. Each of the elements 30 and 40 is arranged coaxially with the camshaft 10 and the cam pulley 20. The vane housing 30 and the vane rotor 40 are formed by extruding a material made of a light alloy, for example, based on aluminum or the like, to reduce the weight and the rotational inertia. In such a cam phase variable device having a small rotational inertia, the load applied to the rotational force transmitting element connecting the crankshaft and the cam pulley 20 becomes small. Configurable. In the following, the elements 10, 20, 30, and 40 may be collectively referred to as a cam drive system in relation to the element arrangement, rotation balance, and the like in the variable cam phase device.

The vane rotor 40 rotates integrally with the vane housing 30 while being drivingly connected to the vane housing 30 via pressure oil supplied between the vane rotor 30 and the vane housing 30. . The rotational force of the crankshaft is transmitted to the camshaft 10 via the cam pulley 20, the vane housing 30, and the vane rotor 40.

The cam pulley 20 has the boss portion 26 fitted to the camshaft 10 and is rotatable relative to the camshaft 10. In addition, the vane rotor 4
0 is rotatable within the housing 30 within a predetermined angle range of, for example, about 40 degrees with respect to the housing. When the vane rotor 40 rotates inside the housing 30, the rotation phase of the camshaft 10 with respect to the cam pulley 20 changes, and the valve overlap amount between the intake valve and the exhaust valve changes. In this embodiment, when the vane rotor 40 assumes the most retarded rotation position shown in FIG. 6, the valve overlap amount is reduced to substantially zero to improve the startability of the engine. The intake efficiency is improved by increasing the lap amount.

More specifically, the vane rotor 40 has a cylindrical main portion 42 and two vanes 44 provided on the peripheral surface of the rotor main portion 42 so as to be diametrically opposed to each other (FIG. 2). A pin hole 42b (FIG. 3) is formed in the end face of the rotor main body portion 42 on the camshaft side.
A pin hole is formed in the opposite end face of the camshaft 10 in alignment with the above. Then, the vane rotor 4 with respect to the cam shaft 10 is
No. 0 is positioned.

The vane 44 extends radially outward from the vane rotor main body 42. Each of the vanes 44 is formed in a tapered shape (substantially trapezoidal shape in the present embodiment) when viewed in a longitudinal section, whereby the weight of the vane 44 at the radially outer portion is reduced, and therefore, the rotational inertia of the vane 44 is reduced. It is greatly reduced. Further, each vane 44 has a symmetrical cross-sectional shape with respect to the longitudinal axis of the vane passing through the center of rotation of the vane rotor. The vane rotor 40 provided with such a tapered vane 44 has a small rotational inertia, and furthermore, the vane rotor rotation center and, consequently, the cam drive systems 10, 20, 30.
And 40 are rich in rotational balance around the rotational axis, and rotational vibration is suppressed.

The vane housing 30 has a housing body 32 and a housing end wall 34. The housing body 32 has the same number (for example, two) of peripheral walls 32 as the number of vanes.
a, a pair of partition walls 32b, 32c extend inward in the vane rotor radial direction from both edges of each housing peripheral wall portion 32a in parallel with each other. Further, the inner surface of the partition wall 32b of each vane is flush with the inner surface of the partition wall 32c of the other vane, and both partition walls are connected to each other through a partition connecting portion 32d. The inner peripheral surface of the partition coupling portion 32d is formed in an arc shape in a vertical section and is in sliding contact with the outer peripheral surface of the vane rotor main portion 42,
The vane rotor 40 is rotatably supported. A bolt hole 23a through which the bolt 23 is inserted is formed in the partition wall coupling portion 32d.

Since the vane 44 has a tapered shape as described above, the circumferential length of the housing peripheral wall portion 32a can be shortened while the cam phase variable range is required. For this reason, in order to reduce the rotational inertia of the housing 30, the radially outer portion of the housing 30 can be thinned around the partition connecting portion 32d. Each pair of partition walls 32b, 32c of the vane housing 30 includes a housing peripheral wall portion 32a,
A vane accommodating chamber for accommodating the vane 44 is defined in cooperation with the housing end wall 34 and the cam pulley main body 22.
In other words, the cam pulley main body 22 of the present embodiment constitutes a housing member together with the housing elements 32 and 34. A vane seal 49 is disposed between the distal end peripheral surface of the vane 44 and the inner peripheral surface of the housing peripheral wall portion 32a, and the vane housing chamber is formed by the seal 49 and the vane 44 so that the advance oil chamber 47 and the retard oil And a chamber 48 (FIG. 2). That is, the vane housing 30 and the vane rotor 40
Between each pair of oil chambers 47, 48 with each vane 44 interposed therebetween.
Is defined. By supplying pressure oil to one of the oil chambers 47 and 48, the vane rotor 40 is rotated in the housing 30.

The vane housing 30 and the vane rotor 40 according to the present embodiment are obtained by extrusion molding as described above, and the opposing surfaces of the two elements 30, 40 are cut using a broaching machine as necessary. You. By providing the partition walls 32b and 32c of each vane in parallel with each other as described above and by providing the inner surfaces of both partition walls so as to be flush with the inner surfaces of the partition walls 32c and 32b of the other vane which are opposed in the vane rotor diameter direction. Processing is facilitated, processing accuracy is improved, and inspection of the processed surface is facilitated.

Next, supply and discharge of pressure oil to and from the oil chambers 47 and 48 will be described. As shown in FIG. 1, the cam journal 15 is formed with first and second oil passages 15 a and 15 b extending substantially perpendicular to the longitudinal axis of the cam shaft 10. Outer ends of the oil passages 15a and 15b communicate with first and second outlet ports 51 and 52 of an oil control valve (OCV) 50, respectively. OCV50
The first inlet port 53 is connected to an oil supply pipe 63 communicating with the discharge side of an oil pump 62 that pressurizes oil pumped from an oil tank 60, and the second inlet port 54 is connected to a return pipe 64. As described later, the first oil passage 15
a is in communication with the retard side oil chamber 47, and the OCV 50 is
The first inlet port 53 and the first outlet port 51 communicate with each other at a switching position (retard position) 50a shown in FIG.
When the inlet port 54 and the second outlet port 52 communicate with each other, the pressure oil from the oil pump 62 is supplied to the retard side oil chamber 48. On the other hand, the OCV 50 takes another switching position (advance angle position) 50b, and the first inlet port 53 and the second outlet port 52 communicate with each other.
When the first outlet port 51 and the fourth outlet port 51 communicate with each other, pressure oil is supplied to the advance-side oil chamber 47. The OCV 50 is duty-controlled by, for example, an electronic control unit (not shown) in accordance with the engine speed to control the supply and discharge of pressure oil to and from the oil chambers 47 and 48, and to variably control the rotational phase of the cam pulley 20 with respect to the camshaft 10. I am trying to do it. Also, the OCV 50 takes the neutral position 50c, and the inlet port 5
When the communication between the ports 3 and 54 and the outlet ports 51 and 52 is interrupted, the rotational phase is maintained. That is, OCV
Constitutes a hydraulic supply means for rotating the vane rotor 40 to the retard side or the advance side by hydraulic pressure as needed together with the oil pump 62 and the like.

The inner ends of the first and second oil passages 15a, 15b formed in the cam journal 15 and constituting a part of the pressure oil supply / discharge passage are formed by the first and second oil passages formed on the peripheral surface of the cam shaft 10. The two annular grooves 11a and 11b are open.
The camshaft 10 has first radial holes 12 extending from the first annular groove 11a to a position short of the camshaft axis.
a, and a second radial hole 12b extending from the second annular groove 11b to the camshaft axis is formed in the camshaft radial direction. The number of the first radial holes 12a is equal to the number of the vanes. Regardless of the rotational position of the camshaft 10, the hole 12a communicates with the first annular groove 11a, and the hole 12b communicates with the second annular groove 11b. In the camshaft 10, first and second extending from inner ends of the holes 12a and 12b to the camshaft end surface, respectively.
The longitudinal holes 13a, 13b are formed in the camshaft axial direction. One second longitudinal hole 13b is provided on the camshaft axis, and the same number of the first longitudinal holes 13a as the number of vanes is provided at a radial position offset from the camshaft axis.

The second longitudinal hole 13b is a stepped hole, and has a small diameter portion communicating with the second radial hole 12b and a large diameter portion into which the hollow bolt 14 having a hexagonal hole is screwed. I have. The hollow bolt 14 is disposed in a stepped through hole 42a formed coaxially with the vane rotor main body 42, and the head of the hollow bolt 14 is accommodated in a large diameter portion of the stepped through hole 42a. The hollow portion 14a of the hollow bolt 14 is formed by the inner peripheral surface of the vane rotor main portion 42 (the surface on which the stepped through-hole 42a is formed) and the hexagon socket head bolt 36 screwed into the screw hole 35 at the center of the housing end wall 34. It communicates with an oil passage 41 having a U-shaped cross section defined by the inner end surface and the outer surface of the head of the hollow bolt 14 (FIG. 1).

In connection with the pressure oil supply / discharge path to the oil chambers 47 and 48, in the vane rotor 40, the rotor main body 42 has two short holes aligned with the two first longitudinal holes 13 a of the camshaft 10. First longitudinal holes 45a are formed in the axial direction of the vane rotor, and two first radial holes 46a extending radially outward from the respective holes 45a in the vane rotor are formed. The outer end of the hole 46a is open to the outer peripheral surface of the rotor main part 42 near the root of the vane 44 and communicates with the retard side oil chamber 48 (FIG. 2). Also, the first
A second radial hole 46b is formed in the vane rotor main body portion 42 in the vane rotor radial direction at a vane rotor thickness direction position deviated toward the camshaft side with respect to the radial hole 46a (FIG. 1). The hole 46b has an inner end opening at a large diameter portion of the stepped through hole 42a of the rotor main portion 42, and an outer end opening at an outer peripheral surface of the rotor main portion 42 near the root of the vane 44 to advance. It communicates with the corner-side oil chamber 47 (FIG. 2).

The above-mentioned annular groove, radial hole and longitudinal hole constitute an oil passage connecting the oil passage 15a or 15b with the oil chamber 48 or 47. As is apparent from FIG. 2, the two radial holes 46a are provided on one straight line passing through the center of rotation of the vane rotor. For this reason, two holes 46a are simultaneously formed by one hole processing, and the processing cost can be reduced. Further, even if the hole 46a is formed in the vane rotor 40, the rotational balance of the vane rotor 40 with respect to the rotational center of the vane rotor (the rotational balance of the cam drive system) is not impaired. The same applies to the hole 46b.

The variable cam phase device has a lock mechanism for locking the vane 44 at the most retarded rotation position so as to minimize the amount of overlap between the intake valve and the exhaust valve (eg, zero). . As shown in FIGS. 2 to 4, the lock mechanism of the present embodiment has the same number (for example, two) as the number of vanes.
, A lock pin (movable body) 70 and a spring (biasing means) 80. Each lock pin 70 is movably arranged in a lock pin hole 44a formed through each vane 44 in the vane thickness direction. Lock pin 70
A spring chamber (accommodating chamber) 71 for accommodating a spring 80 is formed in the lock pin longitudinal direction at the housing end wall side half of the housing. The lock pin 70 is formed by a spring 80 with a lock hole 22 formed in the cam pulley main body 22.
When the vane rotor 40 moves to the most retarded rotation position and the hydraulic pressure is not supplied to the lock hole, the lock pin tip portion 70a fits into the lock hole 22b. Thus, the vane rotor 40 is locked at the most retarded position (FIGS. 4 and 6). In this locked state, the rotational torque applied from the vane housing 30 to the vane rotor 40 is reduced by two lock pins 7.
0 is shared. At this time, the lock pin 70 is made of, for example, an iron-based material so as to withstand the shearing force applied to the lock pin 70.

The lock pin 70 moves to the housing end wall 34 side in accordance with the supply of the pressurized oil to one of the advance side and the retard side oil chambers 47 and 48, and releases the lock. I have. In the present embodiment, the switching valve responsive to the supply of the pressure oil to the advance-side oil chamber 47 and the supply of the pressure oil to the retard-side oil chamber 48 allows the advance-side oil chamber 47 and the retard-side oil chamber 48 to communicate with each other. The pressure oil from the advance-side oil chamber 47 or the retard-side oil chamber 48 is selectively introduced into the lock hole 22b as the unlock hydraulic pressure while the communication is cut off. Thus, oil chamber 4
According to the configuration in which the unlocking hydraulic pressure from the locks 7 and 48 is introduced into the same portion (lock hole) of the lock mechanism, most of the unlock hydraulic path can be integrated into one system, and the lock mechanism can be made compact and designed. The degree of freedom is improved, processing is simplified, and rotation imbalance of the vane rotor 40 due to the arrangement of the lock mechanism can be prevented or reduced.

As shown in FIG. 4, the switching valve has a valve piston (valve element) 90 composed of a straight pin, and the valve piston 90 is positioned radially outward of the lock pin hole 44a in the vane thickness direction ( It is movably disposed in a valve piston hole 44b extending through the vane 44 in the camshaft axial direction). Valve piston 9
If 0 is constituted by a straight cylindrical straight pin, the valve piston hole 44b may be formed as a straight cylindrical hole. Therefore, the processing of the piston 90 and the piston hole 44b is facilitated and the switching valve is disposed. The rotation imbalance of the vane rotor 40 can be prevented or reduced, and
Since the pressure oil leak from between 0 and 44b is reduced, the pressure oil selection operation of the piston 90 (piston movement in the piston hole) is performed quickly. Vane 4 with valve piston 90
4, the piston hole 44 b can be provided through the vane 44, and the piston hole 44 b can be provided in comparison with the case where the bottomed piston hole is provided on the housing 30 side.
Processing of b becomes easy. When the piston 90 is arranged in the axial direction of the camshaft, the centrifugal force applied to the piston 90 with the rotation of the vane rotor 40 acts in the circumferential direction of the vane rotor, that is, in the diameter direction of the piston. Due to this, it does not move in the piston hole 44b. That is, the movement of the piston 90 in the piston hole for selecting the pressure oil is performed accurately and smoothly without being affected by the centrifugal force. Also,
The piston 90 is at its limit of travel in the housing end wall 3.
4 or the pulley main portion 22, there is no need to provide a stopper for the piston.

As shown in FIG. 5, the end faces of the vane 44 on the housing end wall 34 side and the end face on the cam pulley main body 22 side have oil passages 44c and 44d for supplying unlocking hydraulic pressure.
Are formed respectively. Both ends of the oil passage 44c open to the advance-side oil chamber 47 and the valve piston hole 44b, and both ends of the oil passage 44d open to the retard-side oil chamber 48 and the valve piston hole 44b. This valve piston hole 44b
Communicates with the lock hole 22b. That is, the oil passage 44 e for supplying the unlock hydraulic pressure is formed in the vane 44, and the oil passages 72 and 73 are formed in the lock pin 70. The oil passage 44e extends along the longitudinal axis of the vane, and both ends thereof open to the valve piston hole 44b and the lock pin hole 44a, respectively. The oil passage 72 is formed in the diameter direction of the lock pin, and both ends thereof are
Are respectively opened on the outer peripheral surface of. The open end of the oil passage 72 is enlarged in diameter, and the oil passage 44e and the oil passage 72 are connected regardless of whether the lock pin 70 is in the unlocked position shown in FIG. 3 or the locked position shown in FIG. It is designed to communicate. The oil passage 73 extends along the lock pin longitudinal axis, and both ends thereof are open to the oil passage 72 and the lock hole 22b, respectively.

In order to remove the back pressure at the time of unlocking, a groove 44i communicating with the spring chamber 71 is formed on the housing end wall side of each vane 44, and a breathing hole 44j communicating with the groove 44i is formed in the vane 44. (FIG. 4).
The breathing hole 44j extends in the vane thickness direction, and has a chamfered portion 10a formed annularly around the distal end surface of the camshaft 10.
It is open to. The chamfered portion 10a has a breathing hole 10b formed at the tip of the camshaft 10 in the axial direction of the camshaft, and a breathing hole 10c extending radially outward from the breathing hole 10b toward the outer peripheral surface of the camshaft (FIG. 3). Through the ring space 10d. Element 4 above
4i, 44j, 10a, 10b, and 10c form a communication path that connects the spring chamber 71 to the annular space 10d. As described above, the annular space 10d communicates with the inside of the engine via the oil passage 15c of the cam journal 15.

In the above configuration, when pressure oil is supplied from the advance oil chamber 47 to the valve piston hole 44b via the oil passage 44c, the valve piston 90 is moved to the cam pulley main body 2
2 (FIG. 5), the communication between the oil passage 44d and the oil passage 44e is interrupted by the piston 90 and the oil passage 4
4c communicates with the oil passage 44e through the piston hole 44b, and the pressure oil from the oil chamber 47 is supplied to the oil passage 44e of the vane 44.
And into the lock hole 22b through the oil passages 72 and 73 of the lock pin 70. When pressure oil is supplied from the retard side oil chamber 48 to the valve 44b via the oil passage 44d,
The valve piston 90 moves to the housing end wall 34 side,
The pressurized oil flows through the lock holes 2 through the oil passages 44e, 72 and 73.
2b. The pressure oil supplied from the oil chamber 47 or 48 to the lock hole urges the lock pin 70 toward the housing end wall side against the spring force of the spring 80. At this time, the oil in the spring chamber 71 is
And the breathing hole 44j and the chamfered portion 10 of the camshaft 10
a, it is discharged into the annular space 10d through the breathing holes 10b, 10c, and further returned into the engine through the oil passage 15c of the cam journal 15. As a result, the lock pin 7
0 is released from the lock hole 22b without receiving the back pressure due to the oil in the spring chamber 71, and the lock is smoothly released. Further, the oil in the spring chamber 71 is discharged to the annular space 10d in the cylinder head cover, so that the toothed belt 6 does not deteriorate due to the oil.

In FIG. 4, reference numeral 44h denotes a machining hole for machining the oil passage 44e for supplying the unlock hydraulic pressure. That is, the hole 44h and the oil passage 44e can be formed from the top surface side of the vane 44 by one drilling. Both ends of the processing hole 44h are located on the top surface of the vane 44 and the piston hole 4
4b, the advance side or the retard side oil chambers 47, 4
8 is supplied to the piston hole 44b from the machining hole 44.
Acting directly below the vane seal 49 via h, the sealing performance of the vane seal 49 is improved.

The two lock pin holes 44a are arranged symmetrically with respect to the center of rotation of the vane rotor, and the lock pins 70 accommodated in the lock pin holes 44a are also arranged symmetrically with respect to the center of rotation of the vane rotor. The lock hole 22b and the oil passages 44c and 44d are also arranged symmetrically with respect to the center of rotation of the vane rotor. In this way, by arranging various elements of the lock mechanism symmetrically with respect to the rotation center of the rotor vane, preferably including the oil passage, it is possible to avoid deterioration of the rotational balance of the vane rotor 40 due to the arrangement of the lock mechanism.

The operation of the variable cam phase device having the above configuration will be described below. During engine operation, the engine rotation speed is almost constant and the current cam phase (overlap amount of intake and exhaust valves)
Is appropriate, the oil control valve 50 is held at the neutral position 50c where the communication between the inlet ports 53 and 54 and the outlet ports 51 and 52 is cut off. In this case, the supply and discharge of the pressure oil to the advance side and the retard side oil chambers 47 and 48 are not performed, and the vane 44 of the cam phase variable device
It is immovably restrained by the oil filled in 7,48.
As a result, the cam pulley 20, the vane housing 30, the vane rotor 40, and the camshaft 10 rotate in synchronization with the rotation of the crankshaft while the relative rotational position between the vane housing 30 and the vane rotor 40 is fixed and the cam phase is maintained. Then, the intake valve is opened and closed by the cam 4 of the camshaft 10. As described above, each part of the vane housing 30 and the vane rotor 40 is configured in consideration of the rotational balance with respect to the vane rotor rotation center, and therefore, the rotational vibration caused by the rotation of the elements 30 and 40 is sufficiently suppressed.

Thereafter, when the engine speed rises, the oil control valve 50 connects the first inlet port 53 and the second outlet port 52 with each other and the second inlet port 5
4 is switched to the advanced position 50b where the first outlet port 51 communicates. As a result, the pressure oil from the oil pump 62 is hollow through the second oil passage 15b of the cam journal 15 and the second annular groove 11b, the second radial hole 12b, and the second longitudinal hole 13b of the camshaft 10. The fluid flows into the hollow portion 14a of the bolt 14, and further through the oil passage 41 and the second radial hole 46b of the vane rotor main body 42, the advance side oil chamber 4
7 is supplied. By supplying the pressurized oil to the oil chamber 47, an urging force acts on the vane 44 in the advancing direction (the side of the housing partition 32 c), and the vane 44 discharges the oil in the retarding-side oil chamber 48 while the vane 44 It moves in the advance direction in the vane accommodation room. As a result, the vane rotor 40 rotates relative to the housing 30 in the advance angle direction while rotating together with the vane housing 30, and the cam phase is advanced.

During the movement of the vane 44 in the advance direction, the oil in the retard side oil chamber 48 is supplied to the camshaft 10 via the first radial hole 46a and the first longitudinal hole 45a of the vane rotor main body 42. Flows into the first longitudinal hole 13a and then
The oil is discharged into the cylinder head through the first radial hole 12a and the first annular groove 11a of the camshaft 10, the first oil passage 15a of the cam journal 15, and the oil control valve 50, and returns to the oil tank 60.

When the pressure oil is supplied to the advance-side oil chamber 47 as described above, the pressure oil in the oil chamber 47 passes through the oil passages 44c, 44e, 72 and 73, as described above. And flows into the lock hole 22b to urge the lock pin 70 in the lock release direction. At this time, since the lock pin 70 is already in the unlocked state, this unlocked state is maintained (FIGS. 2 and 3).

Thereafter, when the engine speed decreases, the oil control valve 50 connects the first inlet port 53 and the first outlet port 51 to each other and the second inlet port 5
4 is switched to the retard position 50a shown in FIG. 1 where the second outlet port 52 and the second outlet port 52 communicate with each other. As a result, the pressure oil from the oil pump 62 is supplied to the retard-side oil chamber 48 by following the path corresponding to the oil discharge path when the oil control valve 50 is in the advanced position in the reverse direction. By supplying the pressure oil to the oil chamber 48, the vane 44 is retarded in the retard direction (the housing partition 32b).
Side), the vane 44 is advanced to the advance side oil chamber 47.
It moves in the retard direction in the vane housing chamber of the vane housing 30 while discharging the oil inside. As a result, the vane rotor 4
0 rotates with the vane housing 30 in the retard direction with respect to the housing 30, and the cam phase is retarded. Oil is discharged from the advance side oil chamber 47 by following a path corresponding to the pressure oil supply path when the oil control valve 50 is at the advance position in the reverse direction, and the pressure oil returns to the oil tank 60.

When the pressure oil is supplied to the retard-side oil chamber 48, as described above, the pressure oil in the oil chamber 48 is supplied to the oil passage 44d,
It flows into the lock hole 22b through 44e, 72, and 73, and urges the lock pin 70 in the unlocking direction, whereby the unlocked state is obtained (FIGS. 2 and 3). Immediately before stopping the operation of the engine, the engine is idling. During this idling operation, the oil pump 62 moves from the oil pump 62 to the retarded oil chamber 48 via the oil control valve 50 at the retarded position shown in FIG. 1 so that the vane 44 rotates to the most retarded position in the vane storage chamber. Pressure oil is supplied. As a result, the vane rotor 40 is held at the most retarded position. At this time, the lock pin 70 is substantially aligned with the lock hole 22b, but the unlocked state is maintained by the supply of the pressure oil from the oil chamber 48 to the lock hole 22b.

While the engine is stopped, the lock pin 70 receives the spring force of the spring 80 to lock the lock hole 2.
2b (FIG. 6), and the vane 44 is locked at the most retarded position. While the engine is stopped, the advance-side and retard-side oil chambers 47 and 48 located above the cam journal 15.
The oil inside the cylinder escapes into the cylinder head, but the locked state of the vane 44 is maintained by the spring force of the spring 80.
Therefore, at the time of the next engine start, the vane 44 is locked at the most retarded position suitable for starting the engine, and the engine starts smoothly without occurrence of misfire.

The variable valve mechanism according to the present invention is not limited to the above embodiment, but can be variously modified. For example, in the above-described embodiment, the cam phase variable device having two vanes has been described, but the number of vanes is not limited to two. FIG. 7 illustrates a four-vane apparatus. This apparatus has substantially the same configuration as that of the above-described embodiment except that the number of vanes 44 is four. Elements corresponding to those of the above-described embodiment are indicated by the same reference numerals in FIG. When an oil pump normally used in an engine is used as a pressure oil supply source, there is a restriction on the increase in the rotational force of the vane rotor due to an increase in the oil pressure, but when the number of vanes is increased, the total pressure receiving surface of the entire vane is increased, The vane rotor rotational force generated with the supply and discharge of the pressure oil can be increased. In the modified example of FIG. 7, the lock mechanism is provided only on the two vanes diametrically opposed, but the lock mechanism may be provided on all vanes.

In the above-described embodiment and modified examples, the vane 44 is formed in a trapezoidal cross-section such that the dimension in the vane width direction becomes continuously smaller toward the radially outward side, but is not limited thereto. For example, the vane can be composed of a wide proximal half having an arbitrary cross section such as a rectangular shape or a trapezoidal shape, and a narrow distal half having an arbitrary cross section. Also,
Tapering the vanes is not required.

In the above-described embodiment, the communication passage for communicating the urging means accommodating chamber (spring chamber 71) with the annular space 10d is constituted by the elements 44i, 44j, 10a, 10b and 10c. The invention is not limited to this, and it is not essential to provide a communication path. In the lock mechanism of the above embodiment, the lock hole 22b is provided at a position corresponding to the most retarded rotation position of the vane 44, but slightly more advanced than the most retarded rotation position of the vane 44. The lock hole 22b may be formed at a position deviated to the right, and the peripheral surface of the lock pin tip portion 70a and the peripheral surface of the lock hole 22b may be tapered. In this case, the vane 44 is locked in the locked state.
And a clearance is provided between the vane housing partition wall 32b and the lock release operation characteristics of the lock mechanism are improved.
The occurrence of a tapping sound when the engine is started is prevented.

Although the lock mechanism may be provided on the housing side, it is preferable to provide the lock mechanism on the vane member because the length of the cam phase variable device in the cam axis direction can be made compact.

[0053]

The variable valve mechanism according to the present invention comprises a housing member rotatable integrally with a rotation transmitting member synchronously rotating with a crankshaft, a vane rotatable integrally with the camshaft and rotatable relative to the housing member. Since the member and the lock mechanism for urging the movable body disposed in the vane member by the urging means and fitting the movable body in the lock hole of the housing member are provided, oil leakage from the oil chamber during operation stop of the internal combustion engine is provided. Even if it occurs, the locked state can be maintained by the urging force of the urging means, and the occurrence of misfire at the next start of the internal combustion engine can be prevented. Further, in the present invention, when the hydraulic pressure is supplied to the retard-side oil chamber and when the hydraulic pressure is supplied to the advance-side oil chamber, the hydraulic pressure is guided to the lock hole to disengage the movable body from the lock hole. Hydraulic pressure and the hydraulic pressure from the advance-side oil chamber can act as the unlocking hydraulic pressure in the same part called the lock hole, and most of the unlocking hydraulic supply path can be integrated into one system, making the lock mechanism compact. In addition, the size and weight of the variable valve mechanism can be reduced. By providing the lock pin in the vane member in a configuration in which the hydraulic pressure is guided to the same portion, the length of the vane member in the cam axis direction can be shortened, and the entire cam phase variable device can be configured compact. As a result, not only is the mountability excellent, but also the weight and rotational inertia are reduced, so that the rotational responsiveness of the internal combustion engine is not hindered, and the load on the cam driving force transmission elements such as belts and chains is small and the durability is low. Does not cause deterioration.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view showing a cam phase changing device according to an embodiment of the present invention, taken along line II of FIG. 2;

2 is a cross-sectional view of the variable cam phase device taken along the line II-II of FIG. 3;

FIG. 3 shows the cam phase changing device in the unlocked state as indicated by I in FIG. 2;
It is sectional drawing shown along the II-III line.

FIG. 4 is a partially enlarged cross-sectional view of the variable cam phase device.

FIG. 5 is a sectional view taken along the line VV in FIG. 2;

FIG. 6 is a cross-sectional view showing the cam phase variable device in a locked state.

FIG. 7 is a cross-sectional view showing a four-vane cam phase changing device according to a modification of the present invention.

[Explanation of symbols]

 Reference Signs List 4 cam 10 camshaft 20 cam pulley 22b lock hole 30 vane housing 40 vane rotor 44 vane 44a lock pin hole 44b valve piston hole 44c, 44d, 44e, 72, 73 oil passage 44h working hole 47 advance oil chamber 48 retard oil Chamber 49 Seal 50 Oil control valve 62 Oil pump 70 Lock pin 71 Spring chamber 80 Spring 90 Valve piston

Claims (1)

[Claims] 1. A retarding-side oil chamber and an advancement member are provided between a housing member rotatable integrally with a rotation transmitting member to which a rotational force is transmitted from a crankshaft of an internal combustion engine, and a housing member disposed in the housing member. A camshaft having a vane portion defining a corner-side oil chamber and having a cam portion for opening and closing an intake valve or an exhaust valve of the internal combustion engine is integrally rotatable and relatively rotatable with respect to the housing member. A vane member, a hydraulic pressure supply means for selectively supplying hydraulic pressure to the retard side oil chamber or the advance side oil chamber, and a movable body disposed in the vane member by relative rotation of the vane member. When aligned with the lock hole of the member, the movable body is fitted into the lock hole by the urging force of the urging means disposed in the movable body, and when the hydraulic pressure is supplied to the retard side oil chamber and the advance is made. When supplying hydraulic pressure to the corner side oil chamber, A lock mechanism that guides the movable body to the lock hole and separates the movable body from the lock hole.