JPH11229828A - Valve timing adjusting device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve the fail-safeness during low temperatures with a simple configuration without lowering the responsiveness in a normal state. SOLUTION: A check valve 110 is provided positioned where the advance hydraulic chamber 83 and retard hydraulic chamber 81 of a vane 4b connect. A check valve 120 is provided positioned where an advance hydraulic chamber 84 and a retard hydraulic chamber 82 of a vane 4c connect. At low temperatures only, the check valve 110 and the check valve 120 allow the advance hydraulic chambers 83, 84 and the retard hydraulic chambers 81, 82 to connect, respectively. Accordingly, during restart after failure, the hydraulic oil flows from the advance hydraulic chambers 83, 84 to the retard hydraulic chambers 81, 82, respectively, and a vane rotor 4 moves into the maximum retard position with respect to the shoe housing 7 such that the camshaft is maintained in the maximum retard position with respect to the crank shaft. Therefore, the engine will start reliably and shift into normal operation.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an internal combustion engine (hereinafter referred to as "internal combustion engine").
The opening / closing timing of at least one of an intake valve and an exhaust valve of an “internal combustion engine” (hereinafter referred to as an engine)
The present invention relates to a valve timing adjusting device for changing “opening / closing timing” according to operating conditions.

[0002]

2. Description of the Related Art Conventionally, a camshaft is driven through a timing pulley or a chain sprocket that rotates synchronously with a crankshaft of an engine, and an intake valve and an exhaust valve are driven by a phase difference due to a relative rotation between the timing pulley or the chain sprocket and the camshaft. 2. Description of the Related Art A vane-type valve timing adjusting device that controls valve timing of at least one of valves is known.

A vane type valve timing adjusting device is
A vane that rotates with the camshaft is housed in a housing that rotates with the timing pulley. Then, by adjusting the relative rotational phase difference of the vane with respect to the housing by hydraulic pressure, the cam shaft and the timing pulley are relatively rotated, and at least one of the intake valve and the exhaust valve according to the operating conditions of the engine. Adjusting valve timing.

[0004]

SUMMARY OF THE INVENTION A phase control valve timing adjusting device for controlling the opening and closing timing of an engine valve is intended to improve engine stability, improve fuel efficiency, or reduce exhaust emissions. Since the amount of intake air is small at low load, it is desirable that the amount of residual exhaust gas that deteriorates combustion in the cylinder of the engine be small. During a period in which the intake valve and the exhaust valve are simultaneously open (overlap period), the intake side has a negative pressure due to the throttle and the exhaust side has a positive pressure.
Exhaust gas may be blown back to the intake side, resulting in deterioration of combustion or misfire. Therefore, it is required that the closing timing of the exhaust valve be early and the opening timing of the intake valve be late. Further, if the closing timing of the intake valve is late, pumping loss can be reduced and fuel efficiency can be improved. Therefore, at the time of idling operation and start-up, it is necessary to control the basic phase so that the exhaust valve closes earlier and the intake valve opens later. Here, the condition on the intake side of this basic phase is the most retarded angle, and the condition on the exhaust side is the most advanced angle.

However, when the engine has a medium load or more, the EGR amount is controlled to reduce the pumping loss by using the internal EGR.
In order to improve fuel efficiency and reduce exhaust emissions, it is necessary to advance the valve opening timing on the intake side or delay the valve closing timing on the exhaust side. That is, the intake valve is controlled in the advance direction, and the exhaust valve is controlled in the retard direction. further,
At full load of the engine, a large amount of air must be introduced into the cylinder of the engine.At low speeds, the intake valve closes quickly to prevent backflow to the manifold, and at high speeds, the inertia of air is used to slow down. The intake valve needs to be closed. On the exhaust side, it is necessary to control the exhaust valve so that the exhaust pulsation can be used to the maximum, and to control the exhaust valve to the most advanced angle when the exhaust pulsation cannot be used. That is, on the exhaust side, it is necessary to control the exhaust valve from the most advanced angle to the retarded direction and to control the exhaust valve again in the advanced angle according to the load of the engine from low load.

However, if the operating conditions change at this time, it is desirable that the intake and exhaust valves can be quickly controlled to the required phase. If the intake and exhaust valves cannot be controlled, problems such as engine misfire and unstable combustion occur. Usually, the hydraulic pump of the engine is driven by a crankshaft. However, as a result, the discharge oil amount changes depending on the engine speed, and the discharge oil amount decreases at low rotation speed. For this reason, especially at a high oil temperature, the hydraulic pressure may decrease due to leakage and a decrease in viscosity, and the actuator may not operate. At this time, since the intake side is retarded by the driving torque of the camshaft, it can be the basic phase. However, if an actuator with the same hydraulic piston area as the intake side is used on the exhaust side, it will not be possible to control to the basic position, and residual gas will increase in the engine cylinder, causing misfiring or stopping the engine. May be.

In the valve timing adjusting device disclosed in Japanese Patent Application Laid-Open No. 9-264110, the biasing force of a spring is used to move the intake side to a retarded position or the exhaust side to an advanced position, and Has solved the problem. However, in the above conventional technique, when the engine is running and the valve timing is not locked by the lock pin, for example, the engine is stopped due to a driver's clutch control error or the like, and the engine is left in a low temperature state. Due to the characteristics of the hydraulic actuator, since the hydraulic chamber is closed, oil remains inside the actuator. For this reason, since the viscosity of the hydraulic oil increases as the temperature decreases, a very large pressure loss occurs when the hydraulic oil is discharged or allowed to flow during the operation. Therefore, at low temperatures, the hydraulic oil generated by the engine oil pump cannot reach the mounting position of the hydraulic actuator due to pressure loss, and the force required for operation cannot be generated only by the biasing force of the spring. However, there is a problem that the operation becomes impossible.

Further, when an urging force for moving the exhaust side to the advanced position is used, the required load increases and the physical size increases, and when the temperature increases and the viscosity decreases, the spring load increases. Too much, there is a problem that the pressure required for the operation increases and the responsiveness under actual operating conditions deteriorates. In addition, when a mechanical one-way clutch is used instead of the biasing force of the spring, the load generated by the torque fluctuation of the camshaft cannot generate the necessary force for operating the one-way clutch due to pressure loss, and the one-way clutch is not used. There was a problem that became inoperable.

SUMMARY OF THE INVENTION The present invention has been made to solve such a problem, and has a simple structure and can improve the fail-safe property at low temperatures without deteriorating the responsiveness at normal times. It is intended to provide a device.

[0010]

According to the valve timing adjusting apparatus of the first aspect of the present invention, the working fluid can flow in one direction only at a low temperature at a position where the advance chamber and the retard chamber communicate with each other. Since a possible check valve is provided, the advance chamber and the retard chamber do not communicate with each other at a relatively high temperature after warming up the engine, but communicate with the advance chamber and the retard chamber only at a low temperature. For this reason, at normal times, it is possible to quickly control the intake valve or the exhaust valve to the required phase. At low temperatures, the working fluid generated by the driving means has a small pressure loss and easily generates the force required for operation. can do. Therefore, the fail-safe property at low temperatures can be improved with a simple configuration without deteriorating the responsiveness at normal times.

According to the valve timing adjusting device of the present invention, the driven shaft is a driven shaft for opening and closing the intake valve, and the check valve is such that the working fluid flows from the advance chamber to the retard chamber. Provided. Therefore, at a low temperature, the working fluid generated by the driving means flows from the advance chamber to the retard chamber, and can move the intake side to the retard position. Accordingly, at the time of low temperature, the overlap period in which the exhaust valve and the intake valve are overlapped and opened can be reduced at least to such an extent that the engine can be started, so that a restart at the time of a failure can be made possible. .

According to the valve timing adjusting device of the present invention, the driven shaft is a driven shaft for opening and closing the exhaust valve, and the check valve is such that the working fluid flows from the retard chamber to the advance chamber. Provided. Therefore, at a low temperature, the working fluid generated by the driving means flows from the retard chamber to the advance chamber, and the exhaust side can be moved to the advance position. Accordingly, at the time of low temperature, the overlap period in which the exhaust valve and the intake valve are overlapped and opened can be reduced at least to such an extent that the engine can be started, so that a restart at the time of a failure can be made possible. .

According to the valve timing adjusting device of the present invention, since the check valve is provided on the vane member, the fail-safe operation at a low temperature can be performed with a simple configuration without deteriorating the responsiveness at a normal time. Performance can be efficiently improved. According to the valve timing adjusting device of the present invention, since the check valve is provided in the housing member, the fail-safe operation at a low temperature can be efficiently performed with a simple configuration without deteriorating the responsiveness at a normal time. Can be improved well.

According to the valve timing adjusting device of the present invention, the driven shaft is urged in the direction in which the check valve operates, that is, the driven shaft on the intake side is retarded with respect to the drive shaft. Or by providing an urging means for urging the driven shaft on the exhaust side in a direction advancing with respect to the drive shaft, when the discharge oil amount at low engine rotation is small or at high oil temperature. Even when the oil pressure of the exhaust gas decreases, the overlap period in which the exhaust valve and the intake valve overlap and open can be reduced at least to the extent that the engine can be started. Therefore, the startability of the engine is improved, and misfire and unstable combustion of the engine can be prevented. Further, it is possible to reduce the amount of fuel that is drawn from the intake valve and becomes unburned fuel and discharged from the exhaust valve.

[0015]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A plurality of examples showing the embodiments of the present invention will be described with reference to the drawings. (First Embodiment) FIGS. 1 to 6 show an engine valve timing adjusting apparatus according to a first embodiment of the present invention. As shown in FIGS. 1 and 6, the engine valve timing adjusting device of the first embodiment includes a vane-type intake valve timing adjusting device 100 and a vane-type exhaust valve timing adjusting device 200.

First, an intake valve timing adjusting device 100 will be described with reference to FIGS. The timing pulley 8 shown in FIG. 2 receives a driving force from a crankshaft as a drive shaft of an engine (not shown) by a timing belt (not shown), and rotates in synchronization with the crankshaft. The rear member 50 includes a plate portion 51 and a bearing portion 52, and the plate portion 51, the timing pulley 8, and a shoe housing 7 described later are connected by bolts 53. Camshaft 1 as driven shaft
Is driven by the timing pulley 8 to open and close an intake valve (not shown). The camshaft 1 is supported by a cylinder head (not shown) via a journal portion 2 and is rotatable relative to the timing pulley 8 with a predetermined phase difference. The timing pulley 8 and the camshaft 1 rotate clockwise as viewed from the left in FIG. Hereinafter, this rotation direction is referred to as an advance direction.

In the shoe housing 7, a peripheral wall 71 and a front portion 72 are integrally formed, and together with the rear member 50, constitute a housing member. Both end surfaces in the axial direction of the vane rotor 4 are covered by the front portion 72 of the shoe housing 7 and the plate portion 51 of the rear member 50.
The timing pulley 8, the shoe housing 7, and the rear member 50 constitute a driving-side rotating body, and are coaxially connected to each other by bolts 53.

As shown in FIG. 3, the shoe housing 7 is formed in a trapezoidal shape at substantially equal intervals in the circumferential direction.
7b and 7c. Fan-shaped spaces 55 for accommodating vanes 4a, 4b, 4c as vane members are formed in three circumferential gaps between the shoes 7a, 7b, 7c, respectively, and the inner peripheral surfaces of the shoes 7a, 7b, 7c. Is formed in an arc-shaped cross section.

The vane rotor 4 has vanes 4a, 4b, 4c at substantially equal intervals in the circumferential direction.
4c is rotatably accommodated in a fan-shaped space 55 formed in a circumferential gap between the shoes 7a, 7b, 7c.
Arrows indicating the retard direction and the advance direction shown in FIG. 2 indicate the retard direction and the advance direction of the vane rotor 4 with respect to the shoe housing 7. In FIG. 3, each vane is located at one circumferential end of each fan-shaped space 55, and the vane rotor 4 is at the most retarded position with respect to the shoe housing 7. The most retarded position is defined by the retard side surface of the vane 4b being locked to the advance side surface of the shoe 7a. As shown in FIG. 2, the vane rotor 4 and the bush 6
And is integrally connected to the camshaft 1 to form a driven-side rotating body. The shoe housing 7 that supports the bush 6 is covered with a cover 58 on the side opposite to the timing pulley, and the cover 58 is fixed to the shoe housing 7 with screws 59 by screws. The holes 32 provided in the bolts 5 return the hydraulic oil leaked from the circumferential end of the vane rotor 4 to the cylinder head.

The camshaft 1 and the bush 6 are rotatably fitted to the bearing 52 of the rear member 50 and the inner peripheral wall 72a of the front 72, respectively. Therefore, the camshaft 1 and the vane rotor 4 can rotate relative to the timing pulley 8 and the shoe housing 7 coaxially. As shown in FIG. 3, the seal member 9 is fitted on the outer peripheral wall of the vane rotor 4. Vane rotor 4
A small clearance is provided between the outer peripheral wall of the shoe and the inner peripheral wall of the shoe housing 7, and the seal member 9 prevents the hydraulic oil from leaking between the hydraulic chambers through the clearance. Each of the seal members 9 is pressed toward the inner peripheral wall of the peripheral wall 71 by the urging force of the leaf spring 10.

As shown in FIG. 2, the guide ring 91 is press-fitted and held on the inner wall of the vane 4a.
The stopper piston 17 is inserted in the stopper. The stopper piston 17 is formed in a bottomed cylindrical shape having substantially the same outer diameter, and is accommodated in the guide ring 91 so as to be slidable in the axial direction of the camshaft 1. The stopper piston 17 is biased by the spring 16 toward the front portion 72. The fitting ring 54 is fitted in a fitting hole formed in the front portion 72, and a tapered hole 54 a is formed in an inner peripheral wall of the fitting ring 54. The stopper piston 17 can be fitted into the tapered hole 54a at the most retarded position shown in FIG. When the stopper piston 17 is fitted in the tapered hole 54a and the stopper piston 17 is in contact with the tapered hole 54a in the rotational direction, the relative rotation of the vane rotor 4 with respect to the shoe housing 7 is restricted. That is, the stopper piston 17
And the tapered hole 54a are in the restrained position at the most retarded position. The stopper piston 17, the tapered hole 54a, and the spring 16 constitute a lock mechanism.

The hydraulic chamber 18 on the left side of the flange portion 17b is
The oil passage 19 shown in FIG. 3 communicates with an advanced hydraulic chamber 85 described later. The hydraulic chamber 27 formed on the distal end side of the cylindrical portion 17a communicates with a later-described retard hydraulic chamber 80 via an oil passage 31 shown in FIG. The force received by the hydraulic oil in the hydraulic chamber 27 and the hydraulic chamber 18 by the pressure receiving surface of the cylindrical portion 17a that receives the hydraulic pressure in the hydraulic chamber 27 and the pressure receiving surface of the flange portion 17b that receives the hydraulic pressure in the hydraulic chamber 18 are transmitted from the tapered hole 54a. It works in the direction to pull out the stopper piston 17. When hydraulic oil of a predetermined pressure or more is supplied to the retard hydraulic chamber 80 or the advance hydraulic chamber 85, the stopper piston 17 comes out of the tapered hole 54a against the urging force of the spring 16 due to the hydraulic pressure of the hydraulic oil.

Position of stopper piston 17 and tapered hole 5
The position of 4a means that when the vane rotor 4 is at the most retarded position with respect to the shoe housing 7, that is, when the camshaft 1 is at the most retarded position with respect to the crankshaft, the stopper piston 17 Are set at positions where they can be fitted into the tapered holes 54a. A communication passage 29 communicating with the back pressure chamber 30 of the stopper piston 17 is formed on the side of the rear member 50 of the vane 4a. The communication passage 29 communicates with the communication passage 28 formed in the bearing portion 52 at the most retarded position. Since the communication passage 28 is open to the atmosphere in an oil lubrication space (not shown) of the engine, the back pressure chamber 30 is open to the atmosphere at the most retarded position. Therefore, the movement of the stopper piston 17 is not hindered at the most retarded position. When the vane rotor 4 rotates from the most retarded position to the advanced side, that is, when the vane rotor 4 is rotated to an unconstrained position where the stopper piston 17 and the tapered hole 54a cannot be fitted,
The communication between the communication path 29 and the communication path 28 is cut off.

As shown in FIG. 3, the shoe 7a and the vane 4
a, a retard hydraulic chamber 80 is formed between the shoe 7b and the vane 4b, and a retard hydraulic chamber 81 is formed between the shoe 7b and the vane 4b.
A retard hydraulic chamber 82 is formed between the hydraulic pressure c and the vane 4c. An advanced hydraulic chamber 83 is formed between the shoe 7a and the vane 4b, an advanced hydraulic chamber 84 is formed between the shoe 7b and the vane 4c, and an advanced hydraulic chamber is formed between the shoe 7c and the vane 4a. A chamber 85 is formed.

As shown in FIG. 2, the boss portion 4d of the vane rotor 4 is provided with an oil passage 13 formed in an arc shape at a contact portion with the bush 6. The oil passage 13 communicates with a hydraulic pump or a drain (not shown) as driving means via the oil passage 12 and the entire circumferential groove 11. The hydraulic pump also serves as a drive source for engine lubrication oil. Further, the oil passage 13 communicates with the advance hydraulic chambers 83 and 84 via the oil passages 56 and 57 as shown in FIG. The hydraulic chamber 18 communicates with the advance hydraulic chamber 85 via the oil passage 40.

As shown in FIG. 1, the vane rotor 4 has
An arc-shaped oil passage 22 and a single hole 23 are provided at a contact portion with the camshaft 1, and the oil passage 22 and the single hole 23 are provided.
Is connected to the hydraulic pump or drain via the entire circumferential groove 20 of the journal portion 2. Further, the oil passage 22 and the single hole 23 communicate with the retard hydraulic chambers 80, 81 and 82 by oil passages 60, 61 and 62, respectively, and communicate with the hydraulic chamber 27 via the oil passage 31 shown in FIG. doing.

The vane 4b of the vane rotor 4 is provided with a check valve 110 as a check valve at a position where the advance hydraulic chamber 83 and the retard hydraulic chamber 81 communicate with each other. The vane 4c is provided with a check valve 120 as a check valve at a position where the advance hydraulic chamber 84 and the retard hydraulic chamber 82 communicate with each other. The check valve 110 and the check valve 120 are check valves capable of flowing hydraulic oil in one direction only when the temperature is low, and the advance hydraulic chamber 83 and the retard hydraulic chamber 8 only when the temperature is low.
1 and the advance hydraulic chamber 84 and the retard hydraulic chamber 82 can communicate with each other.

Next, the configuration of the check valve 110 will be described in detail with reference to FIGS. Here, FIG. 4 shows the check valve 110 at the time of high temperature, and FIG. 5 shows the check valve 110 at the time of low temperature. In addition, the check valve 120 has the same configuration as the check valve 110, and a description thereof will be omitted. As shown in FIGS. 4 and 5, the check valve 110 includes a housing 111, a ball 112, a guide 113, a shape memory alloy spring 114, and a bias spring 115. Housing 111
Accommodates therein a ball 112, a guide 113, a shape memory alloy spring 114, and a bias spring 115. The shape memory alloy spring 114 is made of a known shape memory alloy, and is arranged inside the guide 113. The bias spring 115 is disposed inside the shape memory alloy spring 114, and presses the ball 112 against the housing 111 against the weight of the ball 112 to determine the initial position of the ball 112.

As shown in FIG. 4, at a high temperature, the shape memory alloy spring 114 is expanded and the bias spring 1
15 and the ball 112 are pressed against the housing 111. At this time, the spring load of the bias spring 115 and the shape memory alloy spring 114 is generated due to the drive torque fluctuation of the camshaft 1, and the hydraulic pressure applied to the advance hydraulic chamber 83 is set to be larger than the force acting on the ball 112. The communication between the advance hydraulic chamber 83 and the retard hydraulic chamber 81 is cut off. Therefore, hydraulic oil does not flow in both directions.

As shown in FIG. 5, at a low temperature, the shape memory alloy spring 114 contracts and does not come into contact with the ball 112. For this reason, the load acting on the ball 112 is only the bias spring 115. However, as described above, this load is only a force against the weight of the ball 112 and the like, and when the hydraulic pressure applied to the advance hydraulic chamber 83 increases (at this time, the hydraulic pressure applied to the retard hydraulic chamber 81 decreases), the load is easily reduced. Then, the ball 112 is separated from the housing 111 to open the valve and the hydraulic oil can flow from the advance hydraulic chamber 83 to the retard hydraulic chamber 81. However, even if the hydraulic pressure applied to the retard hydraulic pressure chamber 81 increases and the hydraulic pressure applied to the advanced hydraulic pressure chamber 83 decreases, the ball 112 is pressed against the housing 111,
Hydraulic oil does not flow from the retard hydraulic chamber 81 to the advance hydraulic chamber 83.

As described above, the check valve 110 is configured so that the operating oil can flow from the advance hydraulic chamber 83 to the retard hydraulic chamber 81 only at a low temperature. Only when the temperature is low, the hydraulic oil can flow from the advance hydraulic chamber 84 to the retard hydraulic chamber 82. Next, the exhaust valve timing adjusting device 200 will be described with reference to FIG. Components that are substantially the same as those of the intake valve timing adjustment device 100 are denoted by the same reference numerals.

As shown in FIG. 6, the vane rotor 4 has
An arcuate oil passage 22 and a single hole 23 are provided at a contact portion with the camshaft, and the oil passage 22 and the single hole 23 communicate with a hydraulic pump or a drain. Further, the oil passage 22 and the single hole 23 communicate with advance hydraulic chambers 85, 84, 83 through oil passages 60, 61, 62, respectively.

The vane 4b of the vane rotor 4 is provided with a check valve 130 as a check valve at a position where the retard hydraulic chamber 81 and the advance hydraulic chamber 83 communicate with each other. The vane 4c is provided with a check valve 140 as a check valve at a position where the retard hydraulic chamber 82 and the advance hydraulic chamber 84 communicate with each other. The check valves 130 and 140 are provided with check valves having the same configuration as the check valve 110 shown in FIGS.

Accordingly, the check valve 130 is configured to allow the hydraulic oil to flow from the retard hydraulic chamber 81 to the advance hydraulic chamber 83 only at low temperatures, and the check valve 140 is controlled only at low temperatures. In this configuration, hydraulic oil can flow from the retard hydraulic chamber 82 to the advance hydraulic chamber 84.
Next, the operation of the valve timing adjusting device will be described.

(1) When the engine is stopped (1-1) Intake valve timing adjusting device 100 When the engine is stopped, the advance hydraulic chambers 83, 84, 85 are released to the drain side, and the retard hydraulic chambers 80, 81 , 82, the hydraulic control valve is switch-controlled so that the operating hydraulic pressure is maintained. Then, since the communication between the retard hydraulic chamber 81 and the advance hydraulic chamber 83 and the communication between the retard hydraulic chamber 82 and the advance hydraulic chamber 84 are interrupted by the check valves 110 and 120, the retard hydraulic chamber 81 Advance hydraulic chamber 8 from
The hydraulic oil does not flow through the hydraulic chamber 82 and the retard hydraulic chamber 82
Hydraulic oil does not flow from the hydraulic oil chamber 84 to the advance hydraulic chamber 84. Accordingly, the vane rotor 4 moves to the most retarded position shown in FIG. 1 with respect to the shoe housing 7, and the front portion 72 of the rear member 50 and the vane rotor 4 are coupled by the lock mechanism. 1 is held at the most retarded position.

(1-2) Exhaust Valve Timing Adjustment Device 2
00 When the engine is stopped, the retard hydraulic chambers 80, 81, 82 are released to the drain side, and the hydraulic control valves are held in the advance hydraulic chambers 83, 84, 85 so that the operating hydraulic pressure is maintained. Switching control is performed. Then, the communication between the retard hydraulic chamber 81 and the advance hydraulic chamber 83 is interrupted by the check valve 130, and the communication between the retard hydraulic chamber 82 and the advance hydraulic chamber 84 is interrupted by the check valve 140. , Advanced hydraulic chamber 8
Hydraulic oil does not flow from 3 to the retard hydraulic chamber 81, nor does hydraulic oil flow from the advance hydraulic chamber 84 to the retard hydraulic chamber 82. Accordingly, the vane rotor 4 moves to the most advanced position shown in FIG. 6 with respect to the shoe housing 7, and the front portion of the rear member and the vane rotor 4 are connected by the lock mechanism. It is held at the angular position.

(1-3) In the most retarded state of the camshaft 1 on the intake side and the most advanced state of the camshaft on the exhaust side, the valve opening periods of the exhaust valve and the intake valve are designed not to overlap. Therefore, the amount of combustion gas remaining in the cylinder of the engine, that is, the so-called internal EGR amount can be reduced, and the engine starts normally. (2) During normal engine operation (2-1) Intake valve timing adjusting device 100 Until the operating oil pressure applied to each oil passage and each hydraulic chamber becomes larger than a predetermined pressure, front portion 72 and vane rotor 4 are locked by a lock mechanism. Since the camshaft 1 is held in the coupled state, the camshaft 1 is at the most retarded position with respect to the timing pulley 8.

When hydraulic oil having a hydraulic pressure greater than a predetermined pressure is introduced into each oil passage and each hydraulic chamber, the connection between the front portion 72 and the vane rotor 4 by the lock mechanism is released.
Accordingly, the operating oil pressure applied to the retard hydraulic chambers 80, 81, 82 and the advance hydraulic chambers 83, 84, 85 causes the vane rotor 4 to relatively rotate with respect to the shoe housing 7, and the cam shaft 1 relative to the timing pulley 8. The phase difference is adjusted. At this time, since the intake valve timing adjusting device 100 is in a high temperature state, the communication between the retard hydraulic chamber 81 and the advance hydraulic chamber 83 is interrupted by the check valve 110, and the retard hydraulic chamber 82 is controlled by the check valve 120. The communication with the advance hydraulic chamber 84 is interrupted. Therefore, the hydraulic oil does not flow in both directions.

(2-2) Exhaust Valve Timing Adjustment Device 2
Until the operating oil pressure applied to each oil passage and each hydraulic chamber becomes larger than a predetermined pressure, the front portion and the vane rotor 4 are held in a coupled state by the lock mechanism. It is in the most advanced position. When working pressure oil having a pressure higher than the predetermined pressure is introduced into each oil passage and each hydraulic chamber, the connection between the front portion and the vane rotor 4 by the lock mechanism is released. Therefore,
Retard hydraulic chambers 80, 81, 82, advance hydraulic chambers 83, 84,
The operating oil pressure applied to 85 causes the vane rotor 4 to relatively rotate with respect to the shoe housing 7, thereby adjusting the relative phase difference of the camshaft with respect to the timing pulley. At this time, since the exhaust valve timing adjusting device 200 is in a high temperature state, the communication between the retard hydraulic chamber 81 and the advance hydraulic chamber 83 is interrupted by the check valve 130, and the retard hydraulic chamber 82 is controlled by the check valve 140. The communication with the advance hydraulic chamber 84 is interrupted. Therefore, the hydraulic oil does not flow in both directions.

(2-3) During normal operation of the engine, the intake valve or the exhaust valve can be quickly controlled to the required phase, and the internal EGR amount can be reduced. Therefore, since the unburned fuel is prevented from being discharged into the exhaust gas, the effect of purifying the exhaust gas is improved. (3) At the time of failure (3-1) Intake valve timing adjustment device 100 At a position where the valve timing is not locked by the lock mechanism during normal operation of the engine, for example, the engine stops due to a driver's clutch control error, etc. When left in the state, the advance hydraulic chamber 8 is operated by the check valve 110.
3 allows the hydraulic oil to flow to the retard hydraulic chamber 81, and the check valve 120 allows the hydraulic oil to flow from the advance hydraulic chamber 84 to the retard hydraulic chamber 82. For this reason, at the time of restart, as shown in FIG. 7A, when a positive torque acts on the camshaft 1 at t1, hydraulic oil flows from the advance hydraulic chamber 83 to the retard hydraulic chamber 81, and Hydraulic chamber 8
4 flows into the retard hydraulic chamber 82. Therefore,
The vane rotor 4 moves to the most retarded position with respect to the shoe housing 7 and the front portion 72 of the rear member 50 and the vane rotor 4 are coupled by the lock mechanism. It is held at the retard position.

(3-2) Exhaust Valve Timing Adjustment Device 2
00 The check valve 130 allows the hydraulic oil to flow from the retard hydraulic chamber 81 to the advance hydraulic chamber 83, and the check valve 14
A value of 0 enables the hydraulic oil to flow from the retard hydraulic chamber 82 to the advance hydraulic chamber 84. Therefore, at the time of restart, FIG.
As shown in (B), when a negative torque acts on the camshaft at t2, the retard hydraulic chamber 81 shifts from the advance hydraulic chamber 8
3 flows from the retard hydraulic chamber 82 to the advance hydraulic chamber 84.
Hydraulic oil flows through For this reason, the vane rotor 4 moves to the most advanced position with respect to the shoe housing 7, and the front portion of the rear member and the vane rotor 4 are connected by the lock mechanism. Therefore, the camshaft is finally held at the most advanced position with respect to the timing pulley.

(3-3) At the time of restart after a failure, the overlap period in which the exhaust valve and the intake valve overlap and open can be reduced at least to the extent that the engine can be started. Combustion gas, internal EG
The R amount can be reduced, and the engine can be restarted. In the first embodiment described above, when the engine is restarted after a failure, the intake-side camshaft 1 is held at the most retarded position with respect to the crankshaft, and the exhaust-side camshaft is held at the most retarded position with respect to the crankshaft. Since the engine is held at the advanced position, the engine is reliably started and the engine shifts to a normal operation state.

(Second Embodiment) FIGS. 8 to 11 show an engine valve timing apparatus according to a second embodiment of the present invention. As shown in FIGS. 8 and 11, the engine valve timing device of the second embodiment includes a vane-type intake valve timing device 300 and a vane-type exhaust valve timing device 400. Components substantially the same as those in the first embodiment are denoted by the same reference numerals.

As shown in FIG. 8, the vane rotor 4 has
An arcuate oil passage 22 and a single hole 23 are provided at a contact portion with the camshaft, and the oil passage 22 and the single hole 23 communicate with a hydraulic pump or a drain. Further, the oil passage 22 and the single hole 23 communicate with the retard hydraulic chambers 80, 81, 82 by oil passages 60, 61, 62, respectively.

The shoe 7b of the shoe housing 7 is provided with a check valve 310 as a check valve at a position where the advance hydraulic chamber 84 and the retard hydraulic chamber 81 communicate with each other. The check valve 310 is a check valve that allows hydraulic oil to flow in one direction only at a low temperature, and is used only at a low temperature.
4 and the retard hydraulic chamber 81 can communicate with each other. Next, the configuration of the check valve 310 will be described in detail with reference to FIGS. Here, FIG. 9 shows the check valve 310 at the time of high temperature, and FIG. 10 shows the check valve 310 at the time of low temperature.

As shown in FIGS. 9 and 10, the check valve 310 includes a housing 311, a ball 312, a bias spring 313, a wax element 314, and a hold spring 315. The housing 311 houses therein a ball 312, a bias spring 313, a wax element 314, and a hold spring 315. Bias spring 31
3 is disposed between the ball 312 and the wax element 314, and is opposed to the weight of the ball 312,
The ball 312 is pressed against the housing 311 and the ball 31 is pressed.
2 is determined. The wax element 314 is a known wax element, and includes a piston 316, a seal 317, a sleeve 318, a wax 3
19 and a cup 320.

As shown in FIG. 9, when the temperature is high, the wax 319 of the wax element 314 is expanded and pushes the piston 316 upward in FIG. The piston 316 presses the ball 312 together with the bias spring 313 against the housing 311. At this time,
Spring load of bias spring 313 and piston 316
The load acting on the advance hydraulic chamber 84 and the retard hydraulic chamber 81 is generated because the hydraulic pressure applied to the advance hydraulic chamber 84 is set to be larger than the force acting on the ball 312. Communication with is interrupted. Therefore, hydraulic oil does not flow in both directions. However,
Since the wax 319 keeps expanding due to the temperature change,
The wax element 314 generates a very large load, and the cup 320 may be damaged. However, the load applied to the piston 316 more than necessary can prevent an excessive increase in stress due to the bending of the hold spring 315.

As shown in FIG. 10, at a low temperature, the wax 319 contracts, and the piston 316 descends downward in FIG. For this reason,
The load acting on the ball 312 is the bias spring 31
There will be only three. However, as described above, this load is only a force against the weight of the ball 312 and the like, and the advance hydraulic chamber 8
4 increases (at this time, the retard hydraulic chamber 8
The hydraulic pressure applied to the valve 1 decreases), the ball 312 is easily separated from the housing 311 and the valve is opened, and the hydraulic oil can flow from the advanced hydraulic chamber 84 to the retard hydraulic chamber 81. However, on the contrary, the hydraulic pressure applied to the retard hydraulic chamber 81 increases,
Even if the hydraulic pressure applied to the advance hydraulic chamber 84 decreases, the ball 31
2 is pressed against the housing 311, and no hydraulic oil flows from the retard hydraulic chamber 81 to the advance hydraulic chamber 84.

As described above, the check valve 310 is configured so that hydraulic oil can flow from the advance hydraulic chamber 84 to the retard hydraulic chamber 81 only at low temperatures. Next, FIG.
The exhaust valve timing adjustment device 400 will be described with reference to FIG. Components substantially the same as those of the intake valve timing adjustment device 300 are denoted by the same reference numerals.

As shown in FIG. 11, the vane rotor 4 has an arcuate oil passage 22 at a contact portion with the camshaft.
And the single hole 23, the oil passage 22 and the single hole 2 are provided.
3 communicates with a hydraulic pump or drain. Further, the oil passage 22 and the single hole 23 communicate with advance hydraulic chambers 85, 84, 83 through oil passages 60, 61, 62, respectively.

The shoe 7 b of the shoe housing 7 is provided with a check valve 330 as a check valve at a position where the retard hydraulic chamber 81 and the advance hydraulic chamber 84 communicate with each other. The check valve 330 is provided with a check valve having the same configuration as the check valve 310 shown in FIG. Therefore, the check valve 330 is configured such that hydraulic oil can flow from the retard hydraulic chamber 81 to the advance hydraulic chamber 84 only at low temperatures.

In the second embodiment, at the time of a failure, the intake valve timing adjusting device 300 controls the check valve 310.
This allows hydraulic oil to flow from the advance hydraulic chamber 84 to the retard hydraulic chamber 81, and the exhaust valve timing adjustment device 400 causes the check valve 330 to flow hydraulic oil from the retard hydraulic chamber 81 to the advance hydraulic chamber 84. It becomes possible. Therefore, at the time of restart, the intake valve timing adjusting device 300
Hydraulic fluid flows from the advance hydraulic chamber 84 to the retard hydraulic chamber 81,
Since the vane rotor 4 moves to the most retarded position with respect to the shoe housing 7 and the front part of the rear member and the vane rotor 4 are coupled by the lock mechanism, the cam shaft is held at the most retarded position with respect to the timing pulley. . Also,
The exhaust valve timing adjusting device 400 is provided with the retard hydraulic chamber 8.
Hydraulic oil flows from 1 to the advance hydraulic chamber 84, the vane rotor 4 moves to the most retarded position with respect to the shoe housing 7, and the front portion of the rear member and the vane rotor 4 are connected by the lock mechanism. The camshaft is held at the most retarded position with respect to the timing pulley.

Therefore, at the time of restart after a failure, the overlap period in which the exhaust valve and the intake valve are opened overlappingly can be reduced at least to the extent that the engine can be started, and therefore remains in the cylinder of the engine. The amount of combustion gas and internal EGR can be reduced, and the engine can be restarted. In the second embodiment described above, when the engine is restarted after a failure, the camshaft on the intake side is held at the most retarded position with respect to the crankshaft,
Since the camshaft on the exhaust side is held at the most advanced position with respect to the crankshaft, the engine is reliably started and shifts to a normal operation state.

In the present invention, the camshaft is urged in the direction in which the check valve operates, that is, the intake-side camshaft is urged in a direction that is retarded with respect to the crankshaft, or the camshaft is urged against the crankshaft. A biasing means such as a spring for biasing the camshaft on the exhaust side in the advancing direction may be provided. With the above configuration,
Even when the amount of discharge oil at low engine speed is low or the oil pressure at high oil temperature is low, the overlap period in which the exhaust valve and intake valve overlap and open is reduced to at least the extent that the engine can be started. It is possible. Therefore, the startability of the engine is improved, and misfire and unstable combustion of the engine can be prevented. Further, it is possible to reduce the amount of fuel that is drawn from the intake valve and becomes unburned fuel and discharged from the exhaust valve.

In the above-described embodiments of the present invention, the valve timing adjusting device for driving both the intake valve and the exhaust valve has been described. However, the present invention is applied to the valve timing adjusting device for driving only the intake valve. Alternatively, the present invention may be applied to a valve timing adjustment device that drives only the exhaust valve. In the above embodiments,
Although the description has been given as having the lock mechanism, a configuration without the lock mechanism is also possible.

In the above embodiments, the vane rotor 4 having three vanes has been described. However, in the present invention, the number of vanes may be one or more as long as the configuration allows. In the above embodiments,
Although the configuration in which the rotational driving force of the crankshaft is transmitted to the camshaft by the timing pulley is employed, a configuration using a chain sprocket, a timing gear, or the like may be employed. It is also possible to receive the driving force of the crankshaft as the drive shaft by the vane rotor and rotate the camshaft as the driven shaft and the shoe housing integrally.

[Brief description of the drawings]

FIG. 1 is a sectional view of an intake valve timing adjusting device according to a first embodiment of the present invention, taken along line II of FIG. 2;

FIG. 2 is a longitudinal sectional view showing the intake valve timing adjusting device according to the first embodiment of the present invention.

FIG. 3 is a sectional view taken along line III-III of FIG. 2;

FIG. 4 is a sectional view showing the check valve at a high temperature according to the first embodiment of the present invention.

FIG. 5 is a sectional view showing the check valve at a low temperature according to the first embodiment of the present invention.

FIG. 6 is a sectional view showing an exhaust valve timing adjusting device according to a first embodiment of the present invention.

FIGS. 7A and 7B are diagrams for explaining the operation of the first embodiment of the present invention, wherein FIG. 7A is an intake valve timing adjustment device, and FIG. 7B is an exhaust valve timing adjustment device.

FIG. 8 is a sectional view showing an intake valve timing adjusting device according to a second embodiment of the present invention.

FIG. 9 is a sectional view showing a check valve at a high temperature according to a second embodiment of the present invention.

FIG. 10 is a sectional view showing a check valve at a low temperature according to a second embodiment of the present invention.

FIG. 11 is a sectional view showing an exhaust valve timing adjusting device according to a second embodiment of the present invention.

[Explanation of symbols]

Reference Signs List 1 camshaft (driven shaft) 4 vane rotor 4a, 4b, 4c vane (vane member) 7 shoe housing (housing member) 8 timing pulley 50 rear member (housing member) 55 fan-shaped space (accommodating chamber) 80, 81, 82 slow Angle hydraulic chamber (retard chamber) 83, 84, 85 Advance hydraulic chamber (advance chamber) 100, 300 Valve timing adjustment device for intake 110, 120, 130, 140 Check valve (check valve) 111 Housing 112 Ball 113 Guide 114 Shape memory alloy spring 115 Bias spring 200, 400 Exhaust valve timing adjuster 310, 330 Check valve (check valve) 311 Housing 312 Ball 313 Bias spring 314 Wax element 315 Hold spring 316 Piston 317 318 Sleeve 319 Wax 320 Cup

Claims (6)

[Claims] 1. A driving force transmission system for transmitting driving force from a driving shaft of an internal combustion engine to a driven shaft that opens and closes at least one of an intake valve and an exhaust valve of the internal combustion engine, wherein the driving shaft or the driven shaft is provided. A housing member that rotates together with one of the drive shaft and the other of the drive shaft and the driven shaft, and rotates relative to the housing member only within a predetermined angular range in a housing chamber formed in the housing member. A vane member accommodated therein, an advance chamber for rotating one of the housing member and the vane member relative to the other in an advance angle direction with respect to the other by fluid pressure, and the housing member and the vane member by fluid pressure. A fluid-driven driving means for supplying a working fluid to a retard chamber for rotating one of the vane members relative to the other in a retard direction, It is provided at a position communicating the advance chamber and the retard chamber,
A check valve which allows a working fluid to flow in one direction only at low temperatures. 2. The apparatus according to claim 1, wherein the driven shaft is a driven shaft that opens and closes an intake valve, and the check valve is provided so that a working fluid flows from the advance chamber to the retard chamber. Item 4. The valve timing adjusting device according to Item 1. 3. The driven shaft for opening and closing an exhaust valve, wherein the check valve is provided so that a working fluid flows from the retard chamber to the advance chamber. Item 4. The valve timing adjusting device according to Item 1. 4. The valve timing adjusting device according to claim 1, wherein the check valve is provided on the vane member. 5. The valve timing adjusting device according to claim 1, wherein the check valve is provided on the housing member. 6. The apparatus according to claim 1, further comprising: urging means for urging the driven shaft in a direction in which the check valve operates.
The valve timing adjusting device according to any one of claims 1 to 5.