JP2895709B2 - Valve timing control device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a valve timing control apparatus.

[0002]

2. Description of the Related Art Conventionally, this type of valve timing control apparatus has
For example, one disclosed in JP-A-62-3111 is known. This conventional valve timing control apparatus will be described with reference to FIG.

In a valve timing control device 80 shown in FIG. 2, an intake valve (not shown) or an exhaust valve (not shown) of an engine is engaged with a camshaft 81 so that the camshaft 81 rotates. As a result, the intake valve or the exhaust valve is driven to open and close. A sleeve 83 is fixed around the camshaft 11 via a bolt 82 so as to be integrally rotatable with the camshaft 81, and a helical spline is formed on the outer peripheral surface of the sleeve 83.

A timing pulley 84 is disposed around the sleeve 83 so as to be rotatable relative to the sleeve 83, and a helical spline is formed on an inner peripheral surface of the timing pulley 84. A timing belt 85 is engaged with the external teeth of the timing pulley 84, and the timing pulley 84 is driven to rotate by the crankshaft (not shown) of the engine via the timing belt 85. A case 86 is fixed to the left end of the timing pulley 84 in the figure.

[0005] Outer peripheral surface of sleeve 83 and timing pulley 8
4, between the inner peripheral surface and the piston housing chamber 87 is formed,
A cylindrical piston means 88 is provided in the piston accommodating chamber 87 so as to be movable in the axial direction of the camshaft 81. A sleeve 83 is provided on the inner peripheral surface of the piston means 88.
And a helical spline is formed on the outer peripheral surface of the piston means 88 so as to mesh with the helical spline of the timing pulley 84. Here, when the piston means 88 moves rightward in the figure, the camshaft 81 and the timing pulley 84 are relatively displaced in one circumferential direction. On the other hand, when the piston means 88 moves leftward in the figure, the camshaft 81 and the timing pulley 84 are relatively displaced in the other circumferential direction. As a result, the rotation phase between the camshaft 81 and the timing pulley 84 changes.

[0006] The piston means 88 is divided into two parts in the axial direction of the camshaft 81, and a spring 89 is provided between them. As a result, when the rotational torque is transmitted from the timing pulley 84 to the sleeve 83 via the piston means 88, the backlash generated between the splines is made zero.

A pressure receiving plate 90 is disposed on the left side of the piston means 88 in the drawing, and forms a first oil chamber 91.
A hydraulic passage 92 communicates with the first oil chamber 91.
A hydraulic pressure is supplied to the first oil chamber 91 from a hydraulic pressure supply means (not shown) via a hydraulic passage 92. On the other hand, a second oil chamber 93 is formed on the right side of the piston means 88 in the figure, and a spring 94 is disposed in the second oil chamber 93 so as to urge the piston means 88 leftward in the figure. .

[0008]

In the valve timing control apparatus 80 described above, the hydraulic control valve (not shown) is switched on / off in accordance with the load state of the engine, so that the piston means 88 is switched to the first position. Position (pressure receiving plate 90
Only stops at the position where it contacts the inner surface of the case 86) and the second position (the position where the piston means 88 contacts the inner surface of the timing pulley 84), so that the valve opening / closing timing takes only two timings. Therefore, when the engine is rotating at high speed and under a high load, the intake and exhaust valves can be opened and closed at the optimum timing regardless of whether the piston means 88 is stopped at the first position or the second position. Can not.

In the above-described apparatus 80, even if the first position or the second position is positioned so that the intake / exhaust valve is opened and closed at an optimum time when the engine is rotating at a high speed and under a heavy load, the engine is kept low. At medium speed rotation and high load, the intake and exhaust valves cannot be opened and closed at the optimal time.

[0010] Therefore, the present invention is to open and close the intake and exhaust valves at the optimal timing according to the operating state of the engine, and particularly to open and close the intake and exhaust valves at the optimal timing when the engine is rotating at high speed and under high load. Is a technical problem.

[0011]

Means for Solving the Problems The technical measures taken in the invention of claim 1 to solve the above technical problems are as follows:
A cam shaft for driving the intake and exhaust valves of the engine to open and close; a timing pulley for driving the cam shaft to rotate; a piston storage chamber formed between the cam shaft and the timing pulley; A piston for dividing the oil chamber and transmitting torque from the timing pulley to the camshaft, and moving in the axial direction of the camshaft in the piston housing chamber to change the rotational phase between the camshaft and the timing pulley; A spring disposed in the second oil chamber for urging the piston in a direction to reduce the volume of the first oil chamber, a hydraulic supply passage formed in the camshaft so as to always communicate with the first oil chamber, A hydraulic pressure supply means for supplying a hydraulic pressure to the first oil chamber via a supply path, and a hydraulic pressure supply means disposed in a passage connecting the hydraulic pressure supply path and the hydraulic pressure supply means, The first oil chamber communicates with the hydraulic supply means when the engine is rotating at low to medium speed, high load, and high speed, and the communication between the first oil chamber and the hydraulic supply means is cut off at idling, at low to medium speed, and at low load. A hydraulic control valve, a relief passage formed in the camshaft for discharging oil in the first oil chamber to the drain, and a constant communication with the first oil chamber and with the relief passage in the middle of the movement of the piston in the axial direction. A groove formed in the piston, a return passage formed in the camshaft so as to be able to communicate with the hydraulic supply passage to return a part of the oil supplied to the hydraulic supply passage to the drain, and a journal hydraulic pressure is always introduced. A first hydraulic passage formed in the camshaft so as to always communicate with the introduction hole, a second hydraulic passage disposed in the camshaft so as to be able to communicate with the first hydraulic passage, Cylinder head The first hydraulic passage is disposed in the middle of the first hydraulic passage so as to be exposed, and is opened by centrifugal force when the camshaft rotates at a high speed to communicate the relief passage with the inside of the cylinder head and to communicate the first hydraulic passage with the second hydraulic passage. A governor valve, and a restrictor mechanism for restricting the hydraulic supply passage when the governor valve is opened, wherein the restrictor mechanism is disposed in the camshaft so as to be movable in the axial direction thereof, and is opened from the first hydraulic passage to the second hydraulic passage when the governor valve is opened. The valve body is formed so as to always communicate with a valve body that moves in one direction by a journal oil pressure supplied through the valve, a spring that urges the valve body in a direction opposite to the one direction, and a hydraulic pressure supply passage. That is, it is constituted by a groove that narrows the hydraulic supply passage when it moves in one direction.

[0012]

According to the above technical means, when the engine rotates at a high speed and a high load, the camshaft also rotates at a high speed, so that the governor valve is opened by centrifugal force. As a result, the relief passage is drained through the inside of the cylinder head. Communicate with At the same time, the first oil chamber is communicated with the hydraulic supply means via the hydraulic supply passage by the hydraulic control valve, and the hydraulic pressure is supplied to the first oil chamber via the hydraulic supply passage, and the hydraulic pressure causes the piston to be attached to the spring. It moves in the axial direction of the camshaft against the force. When the groove formed in the piston communicates with the relief passage during the movement of the piston in the axial direction, the oil in the first oil chamber is discharged into the cylinder head through the groove and the relief passage. As a result, the oil pressure in the first oil chamber gradually decreases, becomes smaller than the urging force of the spring, and the piston moves in a direction to reduce the volume of the first oil chamber. During this movement, the communication between the groove and the relief passage is interrupted, the hydraulic pressure in the first oil chamber increases again, and the piston moves by a very small amount against the spring. By repeating such a minute movement of the piston, the pressing force on the piston by the oil pressure in the first oil chamber finally balances the urging force of the spring, and the piston stops at the intermediate advance position. As described above, by stopping the piston at the intermediate advance position when the engine is rotating at a high speed and under a high load, the intake and exhaust valves can be opened and closed at an optimum timing.

In the above operation, if the camshaft rotates at a high speed while the oil pressure is supplied to the first oil chamber, the oil pressure in the first oil chamber becomes high. At this time, since the governor valve is opened, the first hydraulic passage communicates with the second hydraulic passage. As a result, the journal hydraulic pressure is supplied from the introduction hole to the second hydraulic passage via the first hydraulic passage and acts on the valve element of the throttle mechanism. As a result, the valve element moves in the axial direction of the camshaft against the urging force of the spring, so that the hydraulic supply passage is narrowed by the groove. Therefore, the amount of oil supplied into the first oil chamber decreases, and the amount of oil flowing from the first oil chamber into the cylinder head via the relief passage also decreases. Therefore, oil will not clog inside the cylinder head,
The oil in the first oil chamber is reliably returned to the drain.

[0014]

An embodiment of the present invention will be described below with reference to the accompanying drawings.

FIG. 1 is an overall configuration diagram of a valve timing control apparatus according to this embodiment.

In the valve timing control apparatus 10 shown in FIG. 1, the camshaft 11 is connected to the cylinder head 5 of the engine.
The camshaft 11 is engaged with an intake valve (not shown) or an exhaust valve (not shown) of the engine. The valve is driven to open and close. A cup-shaped case 13 is fixed to the left end of the camshaft 11 in the figure via a bolt 12 so as to rotate integrally with the camshaft 11. A helical spline 13 a is formed on the inner peripheral surface of the cup-shaped case 13.

A sleeve 1 is provided around the camshaft 11.
4 is disposed so as to be rotatable relative to the camshaft 11, and a helical spline 14 a is formed on the left outer peripheral portion of the sleeve 14 in the drawing. A timing pulley 16 is fixed to the outer peripheral portion on the right side of the sleeve 14 via a knock pin 15 so as to rotate integrally with the sleeve 14. The teeth of a timing belt (not shown) are engaged with the external teeth of the timing pulley 16, and the timing pulley 16 is driven to rotate by the crankshaft (not shown) of the engine via the timing belt. ing.

Outer peripheral surface of sleeve 14 and cup-shaped case 13
A piston accommodating chamber 18 is formed between the inner surface and the piston accommodating chamber 18. In the piston accommodating chamber 18, a substantially cylindrical piston 19 is provided so as to be movable in the axial direction of the camshaft 11. A helical spline 19a is formed on the outer peripheral surface of the piston 19 so as to mesh with the helical spline 13a of the cup-shaped case 13, and a helical spline 19b is formed on the inner peripheral surface of the piston 19 so as to mesh with the helical spline 14a of the sleeve 14. Is formed.
The inside of the piston housing chamber 18 is partitioned by a piston 19 into a first oil chamber 20 on the front side and a second oil chamber 21 on the rear side. Here, when the piston 19 moves rightward in the figure, the camshaft 11 and the timing pulley 16 are relatively displaced in one circumferential direction. On the other hand, when the piston 19 moves leftward in the figure, the camshaft 11 and the timing pulley 16 are relatively displaced in the other circumferential direction. Thereby, the rotation phase between the camshaft 11 and the timing pulley 16 changes.

A spring 22 is provided in the second oil chamber 21 and urges the piston 19 leftward in the figure. The second oil chamber 21 includes the sleeve 14 and the timing pulley 1
6 and is always in communication with the oil pan 25 via a discharge passage 23 and a discharge passage 24 formed between the oil pan 25 and the oil pan 25. Therefore, the inside of the second oil chamber 21 is always equal to the atmospheric pressure.

The first oil chamber 2 is provided inside the camshaft 11.
0, a hydraulic supply passage 26 is formed so as to always communicate with
The hydraulic supply passage 26 can communicate with the oil pan 25 via a supply hole 28 and a passage 29. The hydraulic supply passage 26 includes a first passage 26a, a passage 27a, a second passage 26b, and a passage 27b.

In the middle of the passage 29, a hydraulic pump (hydraulic supply means) 30 and a hydraulic control valve 31
Are arranged. The hydraulic pump 30 includes an oil pan 25
To feed the oil to the first oil chamber 20 (that is, to supply the oil pressure to the first oil chamber 20). The hydraulic control valve 31 is an electronic control unit (hereinafter referred to as E) to which engine information such as the engine speed and the engine load is input.
Called CU. ) 32 to switch between ON and OFF. In other words, the hydraulic control valve 31 is configured to rotate the first oil chamber 2 when the engine is running at low to medium speed and high load, and when the engine is running at high speed and high load.
0 is communicated with the hydraulic pump 30 so that the communication between the first oil chamber 20 and the hydraulic pump 30 is cut off at the time of idling, at low and medium speed rotation and low load, and at high speed and low load.
It is controlled by U32.

A cup-shaped cover 34 is rotatably engaged on the outer periphery of the cup-shaped case 13 with a predetermined gap 33 therebetween. The cup-shaped cover 34 is screwed onto the timing pulley 16 (not shown). ) And the like so as to be integrally rotatable. An appropriate amount of viscous fluid is sealed in the gap 33 to form a damper. In order to prevent the viscous fluid from leaking to the outside, seal members 35 and 36 are used.
Are arranged.

During operation of the camshaft 11, a variable torque is received from a valve spring (not shown) which engages with an intake / exhaust valve of the engine. Therefore, backlash may occur between the helical splines 13a and 19a and between the helical splines 14a and 19b, and the rotation phase between the camshaft 11 and the timing pulley 16 may change. There is no problem because the shear force is applied to the viscous fluid in the damper to absorb the shear force.

An annular groove (groove) is formed on the inner peripheral surface of the piston 19.
37 is formed and is always in communication with the first oil chamber 20.
The annular groove 37 communicates with the relief passage 41 formed inside the camshaft 11 via the passage 38, the ring groove 39, and the passage 40 during the movement of the piston 19 in the axial direction. . The relief passage 41 can communicate with the oil pan 25 via a governor valve 60 to be described later. As a result, the oil in the first oil chamber 20 can be discharged to the oil pan 25.

An introduction hole 42 for constantly introducing the journal oil pressure is formed in the outer peripheral portion of the camshaft 11, and always communicates with the oil pan 25 via a branch passage 43 branched from the downstream side of the hydraulic pump 30. I have. The introduction hole 42 is
The first hydraulic passage 46 communicates with the first hydraulic passage 46 formed on the axis of the camshaft 11 through the passage 45.
Can communicate with the second hydraulic passage 47 via the governor valve 60.

The aforementioned governor valve 60 is disposed in the middle of the first hydraulic passage 46, and is provided with a cylinder head 50 of the engine.
It is exposed inside. The center of gravity of the governor valve 60 is located below the axis of the camshaft 11 in the figure. The governor valve 60 is opened by the centrifugal force when the camshaft 11 rotates at a high speed to open the relief passage 41 described above.
Are communicated with the inside of the cylinder head 50 and the first hydraulic passage 46 is communicated with the second hydraulic passage 47.

In the housing 61 of the governor valve 60, a cylindrical valve body 62 having a cavity 62a therein is disposed so as to be slidable vertically in the figure, and is urged upward by a spring 63 in the figure. That is, when the centrifugal force applied downward in the figure is greater than the urging force of the spring 63, the valve body 62 moves downward in the figure, and when the centrifugal force is smaller than the urging force of the spring 63, the valve body 62 moves upward in the figure. It moves in the direction. The cavity 62a is always in communication with the oil pan 25 via the inside of the cylinder head 50. A snap ring 64 is fixed to the illustrated upper portion of the housing 61, and the valve body 44 can be seated on the snap ring 64.

The housing 61 has a first passage 65 and a second passage 65.
A passage 66 and a third passage 67 are formed. The first passage 65 is always in communication with the relief passage 41, and the valve body 6
When it moves downward in the figure, it communicates with the cavity 62a. The second passage 66 is always in communication with the first hydraulic passage 46, and the third passage 67 is in communication with the second hydraulic passage 47.
Is always in communication with An annular groove 68 is provided on the outer periphery of the valve body 62.
The annular groove 68 is always in communication with the second passage 66, and the third groove is formed when the valve body 62 moves downward in the drawing.
It communicates with the passage 67. A passage 69 is formed in the valve body 62, and the valve body 62 is
When the seat 4 is seated, it communicates with the second hydraulic passage 47.

A throttle mechanism 70 is provided on the axis of the camshaft 11 to throttle the hydraulic supply passage 26 when the governor valve 60 is open. This aperture mechanism 70
Is composed of a spool valve (valve element) 71, a hydraulic chamber 72, a spring 73, and an annular groove (groove) 74. The spool valve 71 is disposed on the axis of the camshaft 11 so as to be movable in the left-right direction in the figure. The hydraulic chamber 72 is
It is always in communication with the second hydraulic passage 47. Therefore, when the governor valve 60 is opened, that is, when the first hydraulic passage 46 communicates with the second hydraulic passage 47, the journal hydraulic pressure is changed to the hydraulic chamber 72.
The spool valve 71 is moved rightward in the figure by the hydraulic pressure. Spring 73
Urges the spool valve 71 leftward in the figure. The pressing force on the spool valve 71 by the journal oil pressure is larger than the urging force of the spring 73. The annular groove 74 is formed on the outer periphery of the spool valve 71, and the passage 27 a and the passage 27 b of the hydraulic supply passage 26
Is always in communication with The annular groove 74 narrows the passage 27 b of the hydraulic supply passage 26 when the spool valve 71 moves leftward in the drawing against the urging force of the spring 73.

The operation of the valve timing control apparatus 10 constructed as described above will be described.

First, the rotational torque transmitted to the timing pulley 16 via the timing belt during the operation of the engine is transmitted from the sleeve 14 to the helical splines 14a, 19a.
b, piston 19, helical splines 19a, 13a
And transmitted to the camshaft 11 through the bolt 12. As a result, the intake and exhaust valves are driven to open and close.

When the engine is idling and at low and medium speeds and at low load, the ECU 32 controls the hydraulic control valve 31.
Is turned off and the communication between the first oil chamber 20 and the hydraulic pump 30 is cut off, so that no hydraulic pressure is supplied into the first oil chamber 20. Therefore, the piston 19 stops in a state where the piston 19 is in contact with the inner surface of the cup-shaped case 13 by the spring 22. Therefore, the camshaft 11 and the timing pulley 16
Is maintained in the retarded state. Since the governor valve 60 is always closed during the above operation, the communication between the relief passage 41 and the oil pan 25 is cut off, and the communication between the first hydraulic passage 46 and the second hydraulic passage 47 is cut off. I have.

Next, when the engine is running at low to medium speeds and high load, the hydraulic control valve 31 is switched to the ON state by the ECU 32 and the hydraulic pump 30 is connected to the passage 29 and the supply hole 2.
8, second passage 26b, passage 27b, annular groove 74, passage 2
Oil pressure (or oil) is supplied to the first oil chamber 20 via the first passage 7a and the first passage 26a. As a result, the piston 19 moves rightward in the figure against the urging force of the spring 22.
At this time, the sleeve 14 is relatively rotated with respect to the piston 19 by the action of the helical splines 14a and 19b, and the cup-shaped case 13 is relatively rotated with respect to the piston 19 by the action of the helical splines 13a and 19a. Therefore, the timing pulley 16 and the camshaft 11
And the rotation phase of the camshaft 11 is advanced from the rotation phase of the timing pulley 16.
The oil pressure in the first oil chamber 20 slightly leaks to the second oil chamber 21, but is discharged to the oil pan 25 through the discharge passage 23 and the discharge passage 24.

Since the governor valve 60 is closed during the above operation, even if the first oil chamber 20 communicates with the relief passage 41 via the annular groove 37 during the movement of the piston 19 to the right in the figure. The oil in the first oil chamber 20 is not discharged to the oil pan 25 via the relief passage 41. Therefore, the piston 19 continues to move rightward in the figure against the urging force of the spring 22 and stops at the position where it abuts on the timing pulley 16, so that the rotational phase between the camshaft 11 and the timing pulley 16 becomes the maximum. The lead angle is maintained.
At this time, since the governor valve 60 is closed, the first
The communication between the hydraulic passage 46 and the second hydraulic passage 47 is blocked.

Next, when the engine rotates at a high speed and a high load, the camshaft 11 rotates at a high speed, so that the centrifugal force acting on the valve element 62 of the governor valve 60
, The valve body 62 is detached from the snap ring 64 and the relief passage 41 is connected to the cylinder head 5.
0 communicates with the oil pan 25 through the inside. At the same time, the hydraulic control valve 31 is switched to the ON state by the ECU 32, the first oil chamber 20 communicates with the hydraulic pump 30, and the hydraulic pressure is supplied from the hydraulic pump 28 to the first oil chamber 20 as described above. As a result, the piston 19 moves rightward in the figure against the urging force of the spring 22. When the annular groove 37 communicates with the relief passage 41 during the movement of the piston 19 to the right in the figure, the oil in the first oil chamber 20 is filled with the annular groove 37,
Passage 38, ring groove 39, passage 40, relief passage 41
Then, the oil is discharged to the oil pan 25 through the inside of the cylinder head 50. As a result, the oil pressure in the first oil chamber 20 gradually decreases, and when the pressure applied to the piston 19 by the oil pressure becomes smaller than the urging force of the spring 22, the piston 19 moves to the left in the figure. The annular groove 37
When the communication between the first oil chamber 20 and the relief passage 41 is interrupted, the hydraulic pressure in the first oil chamber 20 gradually increases, and the force by the hydraulic pressure becomes larger than the urging force of the spring 22.

As a result, the piston 19 moves rightward in the figure by a small amount. By repeating the movement of the piston 19 by a very small amount in this manner, the pressing force on the piston 19 due to the oil pressure in the first oil chamber 20 becomes equal to the urging force of the spring 22, and the piston 19 moves to the retarded position and the most advanced position. It stops at an intermediate advanced state between the angular state positions. That is,
The rotational phase between the camshaft 11 and the timing pulley 16 is maintained in the intermediate advance state. At this time, communication between the annular groove 37 and the relief passage 41 is interrupted. By stopping the piston 19 at the intermediate advance position when the engine is rotating at a high speed and under a high load, the intake and exhaust valves can be opened and closed at an optimal time.

In the above operation, when the camshaft 11 is rotating at a high speed while the hydraulic pressure (oil) is being supplied to the first oil chamber 20, the hydraulic pressure in the first oil chamber 20 becomes high. . In this state, if the annular groove 37 communicates with the relief passage 41 with the movement of the piston 19, a large amount of oil in the first oil chamber 20 may flow into the cylinder head 50 via the relief passage 41. As a result, there is a risk that the oil may become clogged inside the cylinder head 50.

When the camshaft 11 rotates at a high speed, the valve body 62 of the governor valve 60 separates from the snap ring 64 and moves downward in the figure against the urging force of the spring 63 as described above. The downward movement of the valve body 62 causes the annular groove 68 to communicate with the third passage 67. As a result, the journal oil pressure is supplied to the oil pressure chamber 72 through the first oil pressure passage 46, the first oil passage 66, the annular groove 68, the third oil passage 67, and the second oil pressure passage 47. Move to the left in the figure against the urging force of. Accordingly, the communication area between the annular groove 74 and the passage 27b of the hydraulic pressure supply passage 26 gradually decreases, and the passage 27b is narrowed. As a result, the amount of oil supplied to the first oil chamber 20 decreases, and the amount of oil flowing from the first oil chamber 20 into the cylinder head 50 via the relief passage 41 also decreases. Therefore, the oil does not clog the inside of the cylinder head 50, and the oil in the first oil chamber 20 is reliably returned to the oil pan 25.

When the governor valve 60 is closed with the hydraulic pressure in the hydraulic pressure chamber 72, the third passage 67 communicates with the passage 69, and the hydraulic pressure (or oil) in the hydraulic pressure chamber 72 is reduced to the second hydraulic pressure. Passage 47, third passage 67, passage 69, cavity 62
a and the oil pan 25 through the cylinder head 50.
Is discharged.

Finally, the governor valve 60 is opened when the engine is rotating at high speed and the load is low, but since the hydraulic control valve 31 is switched off by the ECU 32, the hydraulic pressure is transferred from the hydraulic pump 30 to the first oil chamber 20. Not supplied. Therefore, the rotation phase between the camshaft 11 and the timing pulley 16 is maintained in the retarded state, similarly to the operation at the time of idling and at the time of low / medium speed rotation and low load.

Note that the amount of change in the rotational phase between the camshaft 13 and the timing pulley 16 is as follows: retard → intermediate advance, retard → most advance, intermediate advance → most advance, most advance → Any of intermediate advance, maximum advance → retard and intermediate advance → retard can be taken.

[0042]

The present invention has the following effects.

The intake and exhaust valves can be opened and closed at an optimum time when the engine is rotating at a high speed and under a high load.

Further, the amount of oil flowing into the cylinder head through the relief passage at the time of high-speed rotation and high load of the engine can be reduced, and the oil can be prevented from clogging the cylinder head. As a result, the oil in the first oil chamber can be reliably discharged to the drain.

[Brief description of the drawings]

FIG. 1 is an overall configuration diagram of a valve timing control apparatus according to an embodiment.

FIG. 2 is an overall configuration diagram of a valve timing control apparatus according to a conventional technique.

[Explanation of symbols]

 Reference Signs List 10 valve opening / closing timing control device 11 camshaft 16 timing pulley 18 piston storage chamber 19 piston 20 first oil chamber 21 second oil chamber 22 spring 25 oil pan (drain) 26 hydraulic supply passage 30 hydraulic pump (hydraulic supply means) 31 hydraulic Control valve 37 Annular groove (groove) 41 Relief passage 42 Inlet hole 46 First hydraulic passage 47 Second hydraulic passage 50 Cylinder head 60 Governor valve 70 Throttle mechanism 71 Spool valve (valve element) 73 Hydraulic chamber 74 Annular groove (groove)

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-4-269309 (JP, A) JP-A-4-153509 (JP, A) JP-A-5-33614 (JP, A) 110106 (JP, U) Japanese Utility Model 5-19505 (JP, U) (58) Field surveyed (Int. Cl. ⁶ , DB name) F01L 1/34 F02D 13/02

Claims (1)

(57) [Claims] A camshaft for driving an intake / exhaust valve of an engine to open and close; a timing pulley for driving the camshaft to rotate; a piston storage chamber formed between the camshaft and the timing pulley; The camshaft is divided into a first oil chamber and a second oil chamber while transmitting torque from the timing pulley to the camshaft and moving in the piston housing chamber in the axial direction of the camshaft. A piston that changes a rotation phase between the first oil chamber and the timing pulley; a spring that is provided in the second oil chamber and urges the piston in a direction to reduce the volume of the first oil chamber; An oil pressure supply passage formed in the camshaft so as to always communicate with the oil chamber; and an oil supply passage to the first oil chamber via the oil pressure supply passage. A hydraulic pressure supply means for supplying pressure; and a first pressure supply means disposed at a midway of a passage connecting the hydraulic pressure supply path and the hydraulic pressure supply means. A hydraulic control valve that communicates an oil chamber with the hydraulic pressure supply unit and that cuts off communication between the first oil chamber and the hydraulic pressure supply unit when the engine is not in the above state; A relief passage for discharging the oil in the first oil chamber to the drain through the cylinder head of the engine; and a relief passage which is always in communication with the first oil chamber and communicates with the relief passage in the middle of the axial movement of the piston. A groove formed in the piston, an introduction hole for constantly introducing journal oil pressure, a first hydraulic passage formed in the camshaft so as to always communicate with the introduction hole, A second hydraulic passage disposed in the shaft so as to be able to communicate with the first hydraulic passage; and a second hydraulic passage arranged in the middle of the first hydraulic passage so as to be exposed in the cylinder head, and when the camshaft rotates at a high speed. A governor valve that is opened by centrifugal force to communicate the relief passage with the inside of the cylinder head and communicates the first hydraulic passage with the second hydraulic passage; and a throttle mechanism that throttles the hydraulic supply passage when the governor valve is opened. Wherein the throttle mechanism is disposed in the camshaft so as to be movable in the axial direction thereof, and the first mechanism is provided when the governor valve is opened.
A valve element that moves in one direction by a journal oil pressure supplied from the hydraulic path through the second hydraulic path, a spring that urges the valve element in a direction opposite to the one direction, and always communicates with the hydraulic supply path. A valve opening / closing timing control device which is formed in the valve body and narrows the hydraulic pressure supply passage when the valve body moves in the one direction.