JP2000303808A - Valve timing control device for internal combustion engine - Google Patents

Abstract

(57) [Summary] [PROBLEMS] To reduce the size of a device in addition to improving control response of valve timing. SOLUTION: A plunger 14 is slidably attached to a vane body 4 connected to a camshaft, and the pressure of an advance hydraulic chamber 27 is introduced into a pressure chamber 47 in the plunger 14 during advance rotation control. Then, the tip of the plunger 14 is pressed against the inner surface of the housing 2. The projecting tension of the plunger 14 restricts the return of the vane body 4 due to the torque reaction force from the engine valve. The connection passage 50 that connects the pressure chamber 47 to the low-pressure passage 49 during the retard rotation control is opened and closed by the pressure control spool 51. The spool accommodating hole 54 is formed so that its axis q is radially offset from the axis p of the plunger 14, and the connection path 50 is arranged in a space formed by the offset and extending in the axial direction of the plunger 14.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a so-called vane type valve timing control device for varying the opening / closing timing of an intake side or exhaust side engine valve of an internal combustion engine in accordance with an operating condition.

[0002]

2. Description of the Related Art As a conventional valve timing control device, for example, one disclosed in Japanese Patent Application Laid-Open No. 8-121123 is known.

[0003] In brief, this valve timing control device is configured such that a cylindrical housing is integrally mounted on a timing pulley which is a driving rotary member which is driven to rotate by a crankshaft of an engine, and a camshaft is provided in the housing. A vane body fixed to the end of the housing is rotatably housed, and two substantially trapezoidal partition walls projecting radially inward from the inner peripheral surface of the housing and two of the vane bodies An advance side hydraulic chamber and a retard side hydraulic chamber are defined between the blades. The hydraulic pressure is relatively supplied to and discharged from each of the hydraulic chambers on the advance side and the retard side according to the engine operating state, and the drive hydraulic pressure causes the vane body to rotate forward and reverse, thereby causing the timing pulley and the camshaft to rotate. By changing the relative rotation phase, the opening and closing timing of the intake valve is made variable.

It is well known that the camshaft generates positive and negative (forward rotation, reverse rotation) rotation fluctuation torque (alternating torque) due to the spring force of the valve spring during operation of the engine. However, if the large fluctuating torque acts during the rotation driving of the vane body to the advance side or the retard side (during forward / reverse rotation control), the driving oil pressure of the vane body becomes a reaction force of the rotation fluctuation torque. When the vane loses and is pushed back, the rotational behavior of the vane becomes unstable. That is, when the vane body rotates, for example, to the advance side, the drive oil pressure supplied to the advance side hydraulic chamber loses the reaction force of the positive fluctuation torque and advances as shown by the broken line (a) in FIG. It rotates to the advance side while repeating forward rotation and reverse rotation (advance / retreat) to the angle side and the retard side. Accordingly, the camshaft also performs relative rotation with the timing pulley while repeating normal rotation and reverse rotation, so that the control responsiveness of the valve timing, which is the opening / closing timing control of the engine valve, is reduced.

[0005] In particular, in the low-medium rotation region of the engine where the supply oil pressure is low, it has been desired to improve the responsiveness of the device when changing the valve timing from the retard control to the advance control.

Therefore, a pilot check valve comprising a check valve and a pilot valve is provided inside the vane body as in the technique described in Japanese Patent Application Laid-Open No. 8-121123. There is provided an arrangement in which the backflow of the drive oil pressure supplied to the hydraulic chamber on the side or the retard side is restricted to the inside of the oil passage, thereby preventing the vane from reversing due to the fluctuating torque.

[0007]

However, in this conventional example, although the backflow of the driving oil pressure in each hydraulic chamber is prevented by using a pilot check valve, the pilot check valve does not correspond to each hydraulic chamber. The operation is performed by directly using the hydraulic pressure supplied to the hydraulic chamber, and there is a possibility that the operation accuracy may decrease due to a decrease in the ability to hold the hydraulic pressure in the hydraulic chamber. In other words, a small gap is formed between the housing and the vane body that slides and rotates inside the housing, while a small gap is formed between the housing and the adjacent hydraulic chambers in order to ensure good sliding rotation of the vane body. Causes a large differential pressure. For this reason, the hydraulic pressure supplied to one hydraulic chamber may leak through the minute gap into the other hydraulic chamber. As a result, the check function of the pilot check valve (the function of sealing the hydraulic chamber on the side receiving the torque reaction force from the engine valve) is reduced, and the return of the vane caused by the torque reaction force of the engine valve is effectively reduced. May not be stopped.

In addition, the seal member for maintaining the oil tightness in the housing is deteriorated by long-term use.
Even if a hydraulic pressure leaks from each hydraulic chamber due to this deterioration, the check function of the pilot check valve may be reduced.

As a result, the same technical problem as in the former conventional example, such as a decrease in the control response of the valve timing, is brought about.

Therefore, the present applicant has devised a valve timing control device capable of solving such a problem, and has filed Japanese Patent Application No. Hei.
No. 120259 (filed on April 30, 1998).

[0011] The apparatus according to the earlier application is such that a plunger is slidably attached to one of a vane body attached to one of a camshaft and a driving rotary body, and a tubular member attached to the other side. When controlling the forward / reverse rotation of the vane body with respect to the cylindrical member, the distal end of the plunger is pressed against the other side (opposite member facing the other side) of the vane body and the cylindrical member, so that the engine valve is controlled. The basic structure restricts return of the vane body due to torque reaction. In this application, as an example of the device, a plunger is slidably mounted on a vane body, and a pressure chamber in the plunger is moved through a check valve during advance rotation control of the vane body through an advance hydraulic chamber. And at the time of controlling the rotation of the vane on the retard side, through a pressure control spool to communicate with a low-pressure passage (advance-side hydraulic chamber for reducing pressure).

[0012] In the pressure control spool of this device, the spool accommodating hole is formed in the vane coaxially with the plunger accommodating hole (plunger), while the end of the connection path communicating the plunger accommodating hole and the low pressure passage is provided in the spool accommodating spool. An opening is formed in the peripheral wall of the hole, and the connection path is appropriately opened / closed by the forward / backward operation of the spool which is hydraulically controlled.
That is, the pressure control spool closes the opening in the peripheral wall of the spool housing hole during the advance-side rotation control of the vane body, and the spool opens this opening during the retard-side rotation control.

However, in the valve timing control device according to the earlier application, the spool accommodating hole has a structure arranged coaxially with the plunger. Therefore, a connection path connecting the plunger accommodating hole and the peripheral wall of the spool accommodating hole is provided. The plunger must be arranged at a position more than the radius of the spool receiving hole from the extension of the axis of the plunger, and as a result, the radial space on the axial extension of the plunger is largely occupied by the spool receiving hole and the connection path. This causes a problem that it is difficult to make the device compact.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a valve timing control device for an internal combustion engine which can reduce the size of the device in addition to improving the control response of the valve timing.

[0015]

Means for Solving the Problems As means for solving the above-mentioned problems, the invention described in claim 1 is for driving a rotating rotary body driven by a crankshaft of an engine and operating an engine valve on the outer periphery. A camshaft that has a driving cam and is mounted so that the driving rotator can rotate relative to each other if necessary, and that receives power from the driving rotator and rotates in a driven manner; and a camshaft and the driving rotator And a vane body having at least one blade extending radially outward from the center of rotation and radially outward from the center of rotation, and fixed to the other of the camshaft and the driving rotor. And a plurality of partition walls extending on the inner peripheral surface in the direction of the center of rotation of the vane body. A tubular member forming a retard side hydraulic chamber; and a hydraulic circuit for sucking and discharging hydraulic pressure relative to the advance side hydraulic chamber and the retard side hydraulic chamber to rotate the vane body forward and reverse with respect to the cylindrical member. When the vane body is slidably mounted on one of the vane body and the cylindrical member, and when the vane body is controlled to rotate in the forward / reverse direction with respect to the tubular member, the leading end is vaned by hydraulic pressure introduced therein. A plunger that restricts return of the vane body due to torque reaction force from the engine valve by pressing against the other side of the body and the cylindrical member; and a plunger that is slidably attached to the member that holds the plunger. A pressure control spool for communicating the inside of the plunger with the low-pressure passage when releasing the pressing contact, wherein the spool accommodation hole for accommodating the pressure control spool includes a shaft of the plunger. The end of the connection passage that communicates with the low-pressure passage inside the plunger is formed in the peripheral wall of the spool accommodation hole. It is formed so as to be offset from the center in the radial direction, and the connection path is arranged in a space on the axial extension of the plunger formed by the offset.

In the case of the present invention, since the axis of the spool receiving hole is offset from the axis of the plunger, a portion of the inner peripheral surface of the spool receiving hole extends from the extension of the axis of the plunger. Located at a distance less than the radius. The connection path is arranged in a space created by the offset of the spool accommodation hole.

According to a second aspect of the present invention, in the first aspect of the present invention, a main passage portion from the plunger accommodating hole to the vicinity of the opening of the peripheral wall of the spool accommodating hole is defined as the plunger accommodating hole. They were formed in parallel.

In the case of the present invention, the plunger housing hole and the main passage portion of the connection path can be formed by drilling holes from the same direction.

According to a third aspect of the present invention, in the first or second aspect of the present invention, a plunger support block having a plunger receiving hole is formed separately from the vane body and the cylindrical member. The spool accommodating hole and the connection path are formed, and the block is press-fitted and fixed to one of the vane body and the cylindrical member.

In the present invention, since the plunger receiving hole, the spool receiving hole, and the connection path are formed in the plunger support block separate from the vane body and the cylindrical member, these holes can be easily drilled. In addition, a blind cover is not required for forming the connection path. In other words, the end of the connection path on the side opening to the peripheral wall of the spool accommodation hole must be drilled in a direction intersecting with the spool accommodation hole. However, in the case of the present invention, when the plunger support block is press-fitted and fixed to one of the vane and the cylindrical member, the perforated end is closed by the vane and the cylindrical member. can do.

[0021]

Next, embodiments of the present invention will be described with reference to the drawings.

First, a first embodiment shown in FIGS. 1 to 10 will be described. Although the valve ting control device of this embodiment is applied to the intake valve side of the internal combustion engine, it can be applied to the exhaust valve side in a similar manner.

As shown in FIG. 2, the valve timing control device includes a timing sprocket 1 which is a driving rotating body which is rotationally driven by a crankshaft (not shown) of an engine via a timing chain made of synthetic resin, and the timing sprocket. 1, a housing 2 as a tubular member integrally attached to a front end of the camshaft 3, a camshaft 3 assembled so as to be able to rotate relative to the timing sprocket 1 if necessary, and an end of the camshaft 3. A vane body 4 fixed to the housing 2 and rotatably accommodated in the housing 2, a hydraulic circuit 5 for rotating the vane body 4 forward and reverse by hydraulic pressure, and a positive rotation fluctuation torque acting on the camshaft 3. A regulating mechanism 6 for regulating the return of the vane body 4.

As shown in FIGS. 2 and 4, the timing sprocket 1 has teeth 1a on its outer periphery with which a timing chain meshes, and its front end has a front cover 8 and a rear cover 9 on the front and rear end surfaces of a cylindrical body 7. Is fixed by bolts 10. In addition, a fitting hole 12 having a stepped diameter into which a sleeve 11 to be described later is fitted is formed at a central position inside the timing sprocket 1 so as to penetrate therethrough.

The cylindrical body 7 of the housing 2 has four trapezoidal partition walls 13 projecting from the inner peripheral surface thereof at 90 ° intervals. One of the partition walls 13 has a regulating mechanism 6. Of the plunger 14 is provided with a curved one side surface 13a. A holding groove 15 is formed in the center of the tip of each partition 13 along the axial direction, and a sealing member 16 and a leaf spring 17 for pressing the sealing member 16 inward are accommodated in the holding groove 15. .

On the other hand, the camshaft 3 is rotatably supported at the upper end of a cylinder head 18 via a cam bearing 19, and a drive cam (not shown) for opening an intake valve via a valve lifter at a predetermined position on the outer peripheral surface. Are integrally provided, and a flange portion 20 is integrally provided at the front end. The vane body 4 accommodated in the housing 2 is fixed to the flange 20 together with the sleeve 11 by fixing bolts 21.

The vane body 4 has the fixing bolt 2
1 is provided with an annular rotor portion 22 through which the blade 1 is inserted, and four blade portions 23 radially projecting from the outer peripheral surface of the rotor portion 22 at 90 ° intervals. 3 of the four blades 23
One is formed in a rectangular shape having the same thickness, and the other is formed in a rectangular shape thicker than these. Each of these blade portions 23 is disposed between adjacent partition portions 13, 13 of the housing 2. I have. A retaining groove 24 is formed at the tip of each blade 23 along the axial direction. The retaining groove 24 has a seal member 25 in close contact with the inner peripheral surface of the housing and presses the seal member 25 outward. The respective leaf springs 26 are fitted and held. A space between the side surface on one side of each blade portion 23 of the vane body 4 and the partition wall portion 13 facing the partition wall portion 13 is an advance-side hydraulic chamber 27, and the other side surface of each blade portion 23 and the partition wall portion 13 facing the same. The interval is between the retard hydraulic pressure chambers 28. Therefore, in this device, the advance side hydraulic chamber 27
And a pair of retard hydraulic chambers 28 are provided in total.

As shown in FIG. 2, the hydraulic circuit 5 sucks and discharges a hydraulic pressure to and from the advance hydraulic chamber 27, and sucks and discharges a hydraulic pressure to the retard hydraulic chamber 28. There are two hydraulic passages, a second hydraulic passage 30. A supply passage 31 and a drain passage 32 are connected to the two hydraulic passages 29, 30 via electromagnetic switching valves 33 for passage switching, respectively. An oil pump 35 for feeding oil in an oil pan 34 is provided in the supply passage 31, and an end of the drain passage 32 communicates with the oil pan 34.

The first hydraulic passage 29 has a first hydraulic passage 29 formed inside the cylinder head 18 and inside the axis of the camshaft 3.
A passage portion 36, a first oil passage 38 branched and formed in the head portion 37 through the inner axial direction of the fixing bolt 21 and communicating with the first passage portion 36, a small-diameter outer peripheral surface of the head portion 37 and a vane An annular oil chamber 40 formed between the inner peripheral surface of the bolt insertion hole 39 in the rotor portion 22 of the body 4 and communicated with the first oil passage 38
And four branch passages 41 which are formed substantially radially on the rotor portion 22 of the vane body 4 and communicate the annular oil chamber 40 and the advance hydraulic chambers 27.

On the other hand, the second hydraulic passage 30 is formed in a crank shape from the sleeve 11 to the rear cover 9 with a second passage portion 42 formed in the cylinder head 18 and one side inside the camshaft 3. The second passage portion 42 and a second oil passage 43 that communicates with each of the retard hydraulic pressure chambers 28 are formed.

The electromagnetic switching valve 33 has a four-port three
It is a position type, in which the hydraulic passages 29, 30 and the supply passage 31 and the drain passage 32 are relatively switched by the displacement of an internal valve body.
The displacement of the valve body is controlled by the control signal from the control unit 4. The controller 44 detects a current operation state by a signal from a crank angle sensor for detecting an engine speed or an air flow meter for detecting an intake air amount, and controls the timing sprocket 1 based on signals from the crank angle sensor and the cam angle sensor. The relative rotation position with respect to the camshaft 3 is detected.

As shown in FIGS. 1 and 3, the restricting mechanism 6 has a mounting hole 45 formed in one of the blade portions 23 of the vane body 4 having a large thickness so as to face the advance hydraulic chamber 27. Plunger support block 4 press-fitted and fixed in this mounting hole 45.
6, the plunger 14 slidably fitted on the support block 46, and the plunger 14
A check valve 48 that permits only the flow of hydraulic oil into the pressure chamber 47 in the inside;
And a pressure control spool 51 that appropriately opens and closes a connection path 50 that communicates with the pump 9 by hydraulic pressure.

Here, the housing 2 for accommodating the vane body 4 is formed of an iron-based sintered metal, but the vane body 4 is formed of aluminum, magnesium, hard resin or the like for weight reduction. The plunger support block 46 pressed into the mounting hole 45 of the vane body 4 and the plunger 14 fitted in the support block 46 are SC
It is made of iron-based material having high wear resistance, such as r, SCM, and S. However, since the tip of the plunger 14 is pressed against the side surface of the opposing blade 23 with high pressure,
The surface is further subjected to heat treatment such as carburization in order to further enhance deformation resistance and wear resistance.

The plunger support block 46 is formed in a bottomed cylindrical shape having a plunger receiving hole 52 opened to the advance side hydraulic chamber 27 and a thick bottom wall 53, and approximately half of the bottom wall side is the vane body 4. Of the partition wall 13 and a predetermined amount thereof protrudes into the curve of the one side surface 13a of the partition wall 13. The bottom wall 53 of the support block 46 is formed with a spool receiving hole 54 that opens on the opposite side to the plunger receiving hole 52, and the connection path 50 is connected to the plunger receiving hole 52 through the spool receiving hole 54. And the low pressure passage 49 is communicated with the bottom of the base. The connection path 50 communicates with a shaft hole (main passage portion) 55 formed from the bottom of the plunger housing hole 52 along the axial direction of the hole 52, and communicates with the shaft hole 55 and the inside of the spool housing hole 54. A radial hole (opening) 56 is formed on the peripheral wall of the spool housing hole 54. One end of the low-pressure passage 49 of the vane body 4 communicates with the opening end of the spool housing hole 54, and the other end thereof always communicates with the low-pressure region in the housing 2 through a groove (not shown) of the front cover 8. I have.

As shown in FIGS. 1 and 5, the spool accommodating hole 54 of the plunger support block 46 has a smaller diameter than the plunger accommodating hole 52, and its axis q is aligned with the axis p of the plunger 14. It is formed so as to be offset in the radial direction. The connection path 50 (the shaft hole 55 and the radial hole 56) is arranged in a space formed on the bottom wall 53 of the plunger support block 46 on the axial extension of the plunger 14 due to the offset.

The pressure control spool 51 is formed in a cylindrical shape with a bottom and is urged in a direction in which the radial hole 56 is always opened by a spring 57 housed in a spool housing hole 54. The receiving hole 54 is moved forward and backward in the receiving hole 54 by receiving the hydraulic pressure, and the circumferential wall 5
6 is opened and closed. An annular groove 58 is formed on the outer peripheral surface of the bottom wall of the plunger support block 46,
The annular groove 58 is connected to the annular oil chamber 40, which is a passage on the upstream side of the advance hydraulic chamber 27, through a pressure introduction path 59 formed in the blade section 23 of the vane body 4. The bottom wall 53 of the plunger support block 46 has a communication passage 6 for communicating the annular groove 58 with the bottom of the spool receiving hole 54.
0 is formed, and the pressure of the annular oil chamber 40 acts on the end face of the pressure control spool 51 through the communication passage 60. Accordingly, the pressure control spool 51 receives the force of the spring 57 to open the radial hole 56 when the annular oil chamber 40 is in a low pressure state, and when the annular oil chamber 40 becomes high pressure from this state, receives the oil pressure to
Of the radial bore 56
Close.

On the other hand, the plunger 14 is
The base end portion housed in the inside 6 is formed in a concave shape, and that portion is used as a pressure chamber 47, and an introduction path 62 that connects the outer peripheral surface of the front end portion and the pressure chamber 47 is formed. At the end of the introduction passage 62 on the side of the pressure chamber 47, the advance side hydraulic chamber 27 is provided.
A check valve 48 that allows only the flow of hydraulic oil from the pressure chamber 47 into the pressure chamber 47 is provided, and the end of the introduction path 62 on the advance side hydraulic chamber 27 side is always in communication with the same chamber 27. I have. In other words, FIGS. 1 and 5 show a state in which the plunger 14 is retracted to the maximum inside the plunger receiving hole 52. In this state, the end of the introduction path 62 is also located at the inner edge of the plunger receiving hole 52. It communicates with the advance hydraulic chamber 27 through the chamfer 63. A spring 64 is housed in the pressure chamber 47 of the plunger 14, and the spring 64 constantly urges the plunger 14 in the protruding direction.

The pressure control spool 51 is provided with the plunger 1
The check ball 48a of the check valve 48 is formed of SUJ material, ceramic, or the like.

Hereinafter, the operation of the present embodiment will be described.

At the time of engine start and idling operation,
The electromagnetic switching valve 3 is controlled by a control signal from the controller 44.
7, the supply passage 31 communicates with the second hydraulic passage 30, and the drain passage 32 communicates with the first hydraulic passage 29, as shown in FIG. Therefore, the hydraulic pressure pumped from the oil pump 35 is supplied to the retard hydraulic chamber 28 through the second hydraulic passage 30, and the advanced hydraulic chamber 27 is maintained at the low pressure state as when the engine is stopped. Thereby, the blade portion 23 of the vane body 4 is maintained in a state where it is maximally displaced in the direction of the advance side hydraulic chamber 27 (in the retard direction) as shown in FIGS.

Accordingly, the relative rotation position between the timing sprocket 1 and the camshaft 3 is held on the retard side,
The opening / closing timing of the intake valve is controlled to the retard side. This allows
The overlap between the intake valve and the exhaust valve is reduced, so that the backflow of gas after combustion and the blow-by of intake air do not occur, and the rotation of the engine is stabilized.

Here, as shown in FIG. 1, the regulating mechanism 6 uses a low pressure (drain pressure) because the hydraulic pressure acting on the end face of the pressure control spool 51 through the pressure introduction path 59 is low.
As shown in FIG. 5, the pressure control spool 51 opens the radial hole 56 of the connection path 50 while being displaced toward the bottom of the receiving hole 54 by the force of the spring 57, and the pressure chamber 47 in the plunger 14 Maintained in state. Therefore, at this time, the advance-side hydraulic chamber 27 has a low pressure (drain pressure).
In combination with the above, the plunger 14 can move the distal end surface of the partition 13 by only a very weak biasing force of the spring 64.
Abuts on one side surface 13a.

Thereafter, when the vehicle starts and the engine shifts from the low-speed low-load region to the normal operation in the medium-speed medium load region, the electromagnetic switching valve 33 is operated by the control signal from the controller 44 as shown in FIG. Then, the supply passage 31 and the first hydraulic passage 29 are communicated with each other, and the drain passage 32 and the second hydraulic passage 30 are communicated with each other. As a result, the oil pressure in the retard hydraulic chamber 28 is returned from the drain passage 32 to the oil pan 34 through the second hydraulic passage 30 and the pressure in the retard hydraulic chamber 28 becomes low. Is introduced into the advance-side hydraulic chamber 27 through the first hydraulic passage 29, and the blade portion 23 of the vane body 4 is moved toward the retard-side hydraulic chamber 28 (advance angle) due to a difference between these pressures. Direction).

Therefore, the timing sprocket 1 and the camshaft 3 relatively rotate to the other side, and the opening / closing timing of the intake valve is controlled to the advanced side. As a result, the overlap between the intake valve and the exhaust valve increases, and the pump loss of the engine is reduced, and as a result, the engine output is improved.

When the regulating mechanism 6 is switched from the retard side to the advance side, as described above, the first hydraulic passage 29
The high-pressure oil is introduced into the advance-side hydraulic chamber 27 through the oil passage, and the high-pressure in the first hydraulic passage 29 acts on the end face of the pressure control spool 51 from the annular oil chamber 40 through the pressure introduction passage 59, so that the advance-side hydraulic pressure is The high-pressure oil in the chamber 27 is introduced into the pressure chamber 47 by opening the check valve 48 through the introduction path 62 of the plunger 14, and at this time, the pressure control spool 51 receives the oil pressure in the annular oil chamber 40 and Close.
For this reason, the plunger 14 advances by an amount corresponding to the amount of the rotation stroke as shown in FIG. 6 with the clockwise rotation of the vane body 4 from the position shown in FIG. 13 is always kept in contact with one side surface 13a.

Here, the positive fluctuation torque of the camshaft 3 is transmitted to the vane body 4, and this fluctuation torque is
Is temporarily rotated in the counterclockwise direction, the pressure in the pressure chamber 47 increases at this time, and the check valve 48 closes the introduction passage 62.
The backward movement is regulated by the oil pressure of the pressure chamber 47 closed by the pressure. Therefore, the regulating mechanism 6 applies a so-called projecting force to the counterclockwise rotation of the vane body 4 due to the positive fluctuation torque, and the projecting force causes the vane body 4 to rotate.
Regulates the counterclockwise rotation of Therefore, the vane body 4
As shown by the solid line (b) in FIG. 10, the counterclockwise rotation is reliably restricted during the rotation from the most retarded side to the most advanced side, and the clock is combined with the urging force of the spring 64. Rotate quickly in the direction (advance side).

Accordingly, the relative rotation speed of the timing sprocket 1 and the camshaft 3 to the advance side is increased, and the control response of the valve timing is improved.

Since the negative rotation fluctuation torque acting on the camshaft 3 acts as an assisting force for rotating the vane body 4 to the advance side, the control response of the valve timing is further enhanced.

Further, when the engine operation shifts to the high-speed high-load range, the electromagnetic switching valve 33 operates to supply the supply passage 31 and the second hydraulic passage 30, and the drain passage 32 and the first hydraulic In order to make the passage 29 communicate with each other to set the advance side hydraulic chamber 27 to a low pressure and the retard side hydraulic chamber 28 to a high pressure, the vane body 4 rotates counterclockwise as shown in FIGS. Then, the timing sprocket 1 and the camshaft 3 are relatively rotated to one side, and the opening / closing timing of the intake valve is changed to the retard side. As a result, the closing timing of the intake valve is delayed, and the intake charging efficiency is improved.

At this time, the regulating mechanism 6 determines that the pressure introduction path 59 has a low pressure and the pressure control spool 51 has
In order to open 6, the hydraulic oil in the pressure chamber 47 is discharged to the low pressure passage 49 through the connection passage 50. As a result, the projecting tension of the plunger 14 is released, the vane body 4 immediately rotates counterclockwise, and the opening / closing timing of the intake valve is immediately changed to the retard side.

In this valve timing control device, the pressure chamber 47 and the low-pressure passage 49 are controlled by the pressure control spool 51 disposed on the plunger support block 46.
The spool receiving hole 54 for receiving the pressure control spool 51 is provided with a support block 46 such that its axis q is offset from the axis p of the plunger 14 by a predetermined amount in the radial direction. The connection path 50 (the shaft hole 55 and the radial hole 5) is formed in a space formed on the axial extension of the plunger 14 by the offset.
6), the radial space occupied by the spool accommodating hole 54 and the connection path 50 on the plunger support block 46 is reduced, and the diameter of the plunger support block 46 is reduced, and the vane body 4 and the device are accordingly reduced. The overall size can be reduced. In particular, in the case of the device of this embodiment, the vane body 4 is formed of a lightweight material such as aluminum, and the plunger support block 46 is formed of an iron-based metal. Can contribute to the weight reduction of the entire device.

In the case of the plunger support block 46 of this embodiment, the connection path 50 that connects the plunger receiving hole 52 and the spool receiving hole 54 is formed such that the shaft hole 55 as a main passage portion extends in the axial direction of the plunger receiving hole 52. Since it is formed along, there is an advantage that processing of the plunger support block 46 becomes easy when forming the connection path 50. That is, in the case of this embodiment, the processing tool for forming the connection path 50 and the processing tool for forming the plunger receiving hole 52 can be applied to the end face of the plunger support block 46 from the same angle. The setup of the molding becomes easy, and as a result, the processing operation becomes easy and
It can be performed efficiently.

Further, in the valve timing control device of this embodiment, the plunger support block 46 is connected to the vane body 4.
The plunger support block 46 and the plunger receiving hole 52 and the spool receiving hole 54 and the connection path 50 are formed in the plunger supporting block 46, and the plunger supporting block 46 is press-fitted and fixed in the mounting hole 45 of the vane body 4. Therefore, only the support block 46 that slidably supports the plunger 14 and the pressure control spool 51 is formed of an iron-based material having high wear resistance, and the vane body 4 is formed of a lightweight material such as aluminum. In addition, there is an additional advantage that the formation of the connection path 50 and the like is facilitated.
That is, in the case of this embodiment, since the shape of the support block 46 itself is not as complicated as that of the vane body 4, it is possible to easily perform drilling from an arbitrary direction, and furthermore, it is possible to form the radial hole of the connection path 50. Support block 4 for 56
After drilling from the outer peripheral surface of 6, the drilled end can be securely closed only by press-fitting the support block 46 into the mounting hole 45 without providing a blind cover or the like to the drilled end,
For these reasons, the connection path 50 and the like can be easily formed.

In the above, the case where the camshaft 3 is controlled to rotate to either the maximum retard position or the maximum advance position with respect to the timing sprocket 1 has been described. When the relative rotation position is reached, as shown in FIG. 9, the electromagnetic switching valve 33 is switched to an off position (a position in which both the first hydraulic passage 29 and the second hydraulic passage 30 are closed) to obtain a desired valve timing. It is also possible to gain control.

In the first embodiment described above, the open end of the spool accommodating hole 54 formed in the plunger support block 46 is connected to the low-pressure passage 49, while the bottom of the spool accommodating hole 54 is pressure-introduced. 11, the open end of the spool housing hole 54 is connected to the pressure introduction channel 59 of the vane body 4, as in the second embodiment shown in FIG. May be connected to the low-pressure passage 49.

In the case of this embodiment, the pressure control spool 1
A spring 157 for urging the valve 51 in the valve opening direction is disposed on the bottom side of the spool housing hole 52, and
7 is in a low pressure state, the spool 151 is
The connection path 50 is opened by the force of the pressure 57 and the advance side hydraulic chamber 27 is opened.
At the time of the advance-side rotation control in which the pressure becomes high, the spool 151 receives the high pressure in the annular oil chamber 40 and closes the connection path 50.

In the pressure introducing passage 59 of this embodiment, a connection end 59a on the spool housing hole 54 side is formed at the bottom of the mounting hole 45 along the axial direction of the mounting hole 45. For this reason, when machining the vane body 4, the machining tool of the mounting hole 45 and the machining tool of the pressure introduction path 59 can be applied from the same angle. Becomes easier.

In the case of the first embodiment, the pressure control spool 51 is moved by the spring 57 to the spool accommodation hole 5.
The connection passage 50 is opened by urging the bottom of the spool 4, while the pressure on the upstream side of the advance hydraulic chamber 27 is introduced into the bottom of the spool housing hole 54 through the pressure introduction passage 59. However, as in the third embodiment shown in FIGS.
The connection path 250 is closed by biasing the spool accommodating hole 54 toward the bottom of the spool accommodating hole 54, while the pressure of the retard hydraulic chamber 28 may be introduced to the bottom of the spool accommodating hole 54 through the pressure introducing path 259. It is possible.

That is, the pressure control spool 2 of this embodiment
51 is formed at a predetermined position on the peripheral wall thereof with an annular groove 251a and a through hole 251b for connecting the bottom of the annular groove 251a to the inside of the spool 251.
As shown in FIG. 3, when displaced toward the open end of the spool receiving hole 52 against the urging force of the spring 257, the connection passage 250 and the inside of the spool 251 through the annular groove 251a and the through hole 251b. Is to be communicated. The bottom of the spool accommodating hole 52 is in communication with the retard hydraulic chamber 28 through the pressure introducing passage 259, and the spool 251 is retarded during the retard rotation control when the retard hydraulic chamber 28 becomes high pressure. The pressure in the side hydraulic chamber 28 causes the spool housing hole 52 to be displaced toward the opening end.

In the case of the device of this embodiment, substantially the same operation as that of the other embodiments described above can be obtained.
The hydraulic oil discharged from the pressure chamber 47 to the low-pressure passage 49 through the connection passage 250 and the spool accommodating hole 54 at the time of the retard side rotation control flows from the outer surface of the pressure control spool 251 to the annular groove 25.
Since the fluid flows into the spool 251 through the through hole 1a and the through hole 251b, the pressure of the hydraulic oil does not easily act to lift the spool 251 (move the spool 251 in the axial direction). Therefore, during the retard rotation control, the spool 251 can stably maintain the connection path 250 in the open state, and as a result, the retard rotation control is performed quickly.

In the above description, the embodiment in which the vane body is connected to the camshaft and the housing, which is a cylindrical member, is connected to the timing sprocket, which is the driving rotary body, has been described. Alternatively, the cylindrical member may be connected to the camshaft. Further, the plunger and the pressure control spool may be arranged on the housing side which is a cylindrical member.

[0062]

As described above, the invention according to claim 1 is
When controlling the forward / reverse rotation of the vane body with respect to the tubular member, the tip end of the plunger is pressed against the vane body or the tubular member by hydraulic pressure introduced therein, so that the vane body is caused by the torque reaction force from the engine valve. While restricting the return of the plunger, when releasing the press-contact of the plunger, the connection path communicating between the inside of the plunger and the low-pressure passage is opened by the pressure control spool,
Further, a spool accommodating hole for accommodating the spool is formed so that its axis is offset in the radial direction from the axis of the plunger. Since the connection path that connects the peripheral wall of the receiving hole is arranged, the control response of the valve timing can be reliably improved by the function of restricting the return of the vane body by the plunger. Since the spool accommodating hole and the connection path can be arranged compactly in the given radial space, the overall size of the apparatus can be reduced.

According to the second aspect of the present invention, the main passage portion from the plunger accommodating hole to the vicinity of the opening of the peripheral wall of the spool accommodating hole in the connection path is formed in parallel with the plunger accommodating hole. The accommodation hole and the main passage portion of the connection path can be easily formed by drilling from the same direction, and the manufacturing cost can be reduced accordingly.

According to a third aspect of the present invention, a plunger support block having a plunger receiving hole is formed separately from a vane body and a cylindrical member, and the plunger supporting block is formed with the spool receiving hole and a connection path. Since the same block is press-fitted and fixed to one of the members of the vane body and the cylindrical member, it is possible to easily perform the drilling process of each part and to form a connection passage in the peripheral wall of the spool housing hole. There is no need to close the perforated end with a blind lid or the like after the perforation, and these enable production at lower cost.

[Brief description of the drawings]

FIG. 1 is a sectional view taken along line AA of FIG. 2 showing a first embodiment of the present invention.

FIG. 2 is a longitudinal sectional view showing the same embodiment.

FIG. 3 is an exemplary sectional view taken along the line BB of FIG. 2 showing the embodiment;

FIG. 4 is an exploded perspective view showing the same embodiment.

FIG. 5 is a sectional view of a part showing the embodiment.

FIG. 6 is an exemplary sectional view of a part showing the embodiment;

FIG. 7 is a hydraulic circuit diagram showing the same embodiment.

FIG. 8 is a hydraulic circuit diagram showing the same embodiment.

FIG. 9 is a hydraulic circuit diagram showing the same embodiment.

FIG. 10 is a graph showing rotation characteristics of a vane body and torque fluctuation characteristics of a camshaft of the apparatus of the embodiment and a conventional apparatus.

FIG. 11 is a sectional view showing a second embodiment of the present invention.

FIG. 12 is a sectional view of a component according to a third embodiment of the present invention.

FIG. 13 is a cross-sectional view of the component showing the same embodiment.

FIG. 14 is a hydraulic circuit diagram showing the same embodiment.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Timing sprocket (drive rotary body) 2 ... Housing (cylindrical member) 3 ... Camshaft 4 ... Vane body 5 ... Hydraulic circuit 13 ... Partition wall 14 ... Plunger 23 ... Blade part 27 ... Advanced hydraulic chamber 28 ... Slow Corner hydraulic chamber 46 ... Plunger support block 49 ... Low pressure passage 50 ... Connection passage 51,151,251 ... Pressure control spool 52 ... Plunger housing hole 54 ... Spool housing hole 55 ... Shaft hole (main passage portion) 56 ... Radial hole (Aperture)

Claims (3)

[Claims] 1. A drive rotating body which is rotationally driven by a crankshaft of an engine, and a drive cam for operating an engine valve is provided on an outer periphery, and the drive rotary body is assembled so as to be able to relatively rotate as required. A camshaft that is driven and rotated by transmitting power from the driving rotator, and at least one that is fixed to one of the camshaft and the driving rotator and extends radially outward from a rotation center portion. A vane body having one blade portion, and a plurality of partition portions fixed to the other side of the camshaft and the driving rotating body and extending on the inner peripheral surface in the direction of the rotation center of the vane body, The plurality of partition walls are cylindrical members forming advance-side hydraulic chambers and retard-side hydraulic chambers on both sides in the rotation direction of each blade of the vane body; and the advance-side hydraulic chamber and the retard-side hydraulic chamber Relatively oil A hydraulic circuit for forward and reverse rotation relative to the tubular member to said vane body by sucking and discharging, slidably mounted on either side of the vane body and the tubular member,
When controlling the forward and reverse rotation of the vane body with respect to the cylindrical member, the tip of the vane is pressed into contact with the other side of the vane body and the cylindrical member by hydraulic pressure introduced therein, so that the vane due to torque reaction force from the engine valve. A plunger that regulates return of the body, and a pressure control spool that is slidably attached to a member that holds the plunger and communicates with the low-pressure passage inside the plunger when the plunger is released from being pressed. A valve timing control device for an internal combustion engine, wherein a spool accommodation hole for accommodating the pressure control spool is formed along an axial direction of the plunger, and an end of a connection path communicating the inside of the plunger with a low pressure passage. Is formed in the peripheral wall of the spool receiving hole, so that the spool receiving hole is radially offset from the axis of the plunger. A valve timing control device for an internal combustion engine, wherein the connection path is formed in a space formed on the axial extension of a plunger formed by the offset. 2. The connecting passage according to claim 1, wherein a main passage portion from the plunger receiving hole to the vicinity of the opening of the peripheral wall of the spool receiving hole is formed in parallel with the plunger receiving hole. A valve timing control device for an internal combustion engine. 3. A plunger support block having a plunger receiving hole is formed separately from a vane body and a cylindrical member, and the plunger supporting block is formed with a connection path with the spool receiving hole, and the plunger supporting block is connected to the vane body and the cylindrical member. 2. A fixed member press-fitted to one of the side members.
Or a valve timing control device for an internal combustion engine according to item 2.