JP2001012218A - Valve timing control device for internal combustion engine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve the responsiveness to valve timing control and also surely reduce the sliding resistance of a plunger even for a vane body and a cylindrical member made of material of light specific gravity such as aluminum alloy. SOLUTION: A guide bushing 26 is fixed to a vane body 2, and a plunger 6 is slidably attached to the guide bushing 26. The tip of the plunger 6 is pressed against the inner face of a housing 1 by introducing the same pressure as that in a spark-advance side hydraulic chamber 12 into the pressure chamber 27 inside the plunger 6 in controlling the spark-advance side. The returning of the vane body 2 caused by the torque reaction from an engine valve is controlled by the stretching force of the plunger 6. A connection passage 30 communicating the pressure chamber 27 to a low pressure passage 29 is opened and closed in controlling the lag angle side. The vane body 2 is made of material of light specific gravity such as aluminum alloy, and the guide bushing 26 and the plunger 6 are made of iron system material similar to each other.

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 an end of the housing is rotatably housed, and a substantially trapezoidal partition wall portion protruding inward in the radial direction is formed on the inner peripheral surface of the housing. An advance-side hydraulic chamber and a retard-side hydraulic chamber are defined between the vane 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, when the rotation fluctuation 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 fluctuating torque, and the forward and reverse rotations (forward and backward) to the advance side and the retard side as shown by the broken line (a) in FIG. Rotate to the advance side while repeating. Therefore, the camshaft also rotates forward,
Since the rotation relative to the timing pulley is performed while repeating the reverse rotation, the responsiveness of the valve timing control, 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 is 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. A device has been devised which restricts the reverse flow of the drive hydraulic pressure supplied to the hydraulic chamber on the side or the retard side into the oil passage to prevent the vane from reversing due to 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 is not provided in each hydraulic chamber. However, there is a possibility that the operation accuracy may be reduced due to a decrease in the holding capacity of 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 closing the hydraulic chamber on the side receiving the torque reaction force from the engine valve) is reduced, and the return of the vane body caused by the torque reaction force of the engine valve is effectively prevented. Could 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 before, 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 housed in a mounting hole of a vane body, and a pressure chamber in the plunger is provided with a check valve when the vane body is controlled to rotate on the advance side. And a low-pressure passage (low-pressure advance hydraulic chamber) through a pressure control spool disposed in the plunger when the vane body is controlled to rotate on the retard side. Disclose something.

In this device, during the retard rotation control in which the retard hydraulic chamber becomes high in pressure, the pressure chamber communicates with the low-pressure advance hydraulic chamber by operating the pressure control spool to freely move the plunger back and forth. On the other hand, during the rotation control on the advance side, the pressure control spool closes the discharge passage portion, and the high-pressure hydraulic oil in the hydraulic chamber on the advance side opens the check valve and is introduced into the pressure chamber. The discharge of hydraulic oil from the chamber is prevented by the function of the check valve. Therefore,
During advance rotation control in which a positive torque reaction force is transmitted from the engine valve to the vane body, the plunger acts on the plunger to restrict return of the vane body.

In this valve timing control device, a spring for urging the plunger in the projecting direction is interposed between the bottom of the mounting hole of the vane body and the plunger. Even if the plunger receives a fluctuating torque and suddenly rotates in the advance direction, the plunger receives the urging force of the spring and immediately follows this, thereby maintaining the contact between the plunger and the housing. It has become.

In this valve timing control device, it is difficult to set a spring interposed between the mounting hole and the plunger. If the setting of the urging force of the spring is too small, the vane body is not controlled during the advance-side rotation control. When the plunger turns rapidly, the tip of the plunger separates from the housing, causing abnormal noise due to torque fluctuation. Conversely, if the biasing force of the spring is too large, the spring force is applied to the retard rotation control. Large oil pressure must be used,
As a result, the power loss increases.

For this reason, in this device, the sliding force of the plunger is improved in order to increase the responsiveness of the plunger at the time of the advance-side rotation control while keeping the urging force of the spring interposed between the mounting hole and the plunger small. It is strongly desired to reduce dynamic resistance as much as possible.

At present, separately from this, it has been studied to form the vane body and the housing (tubular member) with a material having a low specific gravity, such as an aluminum alloy or a resin, thereby reducing the weight of the entire apparatus. . However, it is extremely difficult to achieve both a reduction in weight and a reduction in the sliding resistance of the plunger described above, and achieving this compatibility has been one of the major problems of this type of apparatus.

That is, in the case of the valve timing control device of the present invention, the leading end of the plunger exerts a projecting force while changing the contact angle with the mating member during the advance rotation control, so that the plunger support portion is At this time, a large moment acts. Therefore, for example, when the vane body and the housing (cylindrical member) are formed of an aluminum alloy and the plunger is formed of the same aluminum alloy, welding is easily generated between the mounting hole and the sliding portion of the plunger. Is formed of an iron-based material having a higher strength than the aluminum alloy, the sliding resistance is reduced, but the aluminum alloy on the mounting hole side is shaved. Further, in any case, since a very large moment acts on the plunger during the rotation control on the advance side, the use of the plunger causes settling to the mounting hole side due to the use over time, and the plunger is likely to slide poorly.

As a countermeasure against this, while the plunger is formed of an iron-based material having a strength greater than that of the aluminum alloy, the inner peripheral surface of the mounting hole is subjected to a surface treatment to enhance wear resistance and lubricity. Although it is conceivable that the surface treatment layer is very thin, a large moment acting on the plunger may cause a crack in the surface treatment layer itself.

Therefore, the present invention not only improves the responsiveness of the valve timing control but also ensures that the sliding resistance of the plunger can be reduced even when the vane or the cylindrical member is formed of a material having a low specific gravity, such as an aluminum alloy. An object of the present invention is to provide a valve timing control device for an internal combustion engine that can reduce the number of valves.

[0021]

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 tubular member, and a pressure in the plunger according to the relative rotation control of the vane body with respect to the tubular member. Pressure control means for controlling the valve, wherein the member on the plunger mounting side of the vane body and the cylindrical member is formed of a material having a lower specific gravity than the plunger. Is provided with a mounting hole, a guide bush made of an iron-based material is fitted and fixed in the mounting hole, and the plunger is formed of the same iron-based material as the guide bush, and the plunger is slid in the guide bush. It was housed freely.

In the case of the present invention, the guide bush and the plunger, which slide upon receiving a large moment, are both formed of an iron-based material having high strength and rigidity. No sagging. In addition, since the guide bush and the plunger that slide with each other are formed of the same material, the linear expansion coefficients of the guide bush and the plunger are the same, and the sliding clearance does not change due to a temperature change.

According to a second aspect of the present invention, in the first aspect of the present invention, the guide bush is fixed to the guide bush such that the tip end protrudes from the mounting hole.

According to the present invention, the plunger can be securely prevented from coming off without making the plunger unnecessarily long. Further, since the tip of the guide bush supporting the plunger approaches the load input portion at the tip of the plunger, the moment acting on the support of the plunger is reduced.

According to a third aspect of the present invention, in the valve timing control device according to the second aspect, the guide bush is attached to the vane body side, and the cylindrical member side has a recess for avoiding interference with the tip of the guide bush. It was provided.

In the case of the present invention, the turning angle of the vane relative to the cylindrical member can be increased by the concave portion provided in the cylindrical member.

According to a fourth aspect of the present invention, the pressure control means permits a check valve that allows only the flow of hydraulic oil from the hydraulic chamber into the plunger, and a spool that opens and closes a connection path communicating the low pressure passage with the inside of the plunger. The valve timing control device according to any one of claims 1 to 3, further comprising:
One end of the connection path is opened at the base outer peripheral surface of the guide bush, while the spool is formed in a cylindrical shape, and the spool is fitted on the base outer peripheral surface of the guide bush, and the sliding of the spool is performed. In the case of the present invention in which the connection path is opened and closed by movement, there is no need to provide a special space for accommodating the spool, and the spool can be easily assembled to the guide bush from the outer peripheral side.

According to a fifth aspect of the present invention, in the invention according to any one of the first to fourth aspects, a hydraulic oil communication port communicating with the inside of the guide bush is formed in the outer peripheral surface of the guide bush. A guide hole for hydraulic oil is drilled in a member on the plunger mounting side of the vane body and the cylindrical member, and the guide bush is fitted and fixed to the member on the plunger mounting side so as to cross the guide hole, The communication port is communicated with the actual use portion side of the guide hole, and the unused portion side of the guide hole is closed at a portion other than the communication port on the outer peripheral surface of the guide bush.

In the case of the present invention, after the guide hole is formed in the member on the plunger mounting side, the guide bush is fitted and fixed in the mounting hole, and the end of the guide hole on the unused portion side is used without using a dedicated component. It becomes possible to close the part.

According to a sixth aspect of the present invention, in the fifth aspect of the invention, the distribution port is formed by an annular groove along the outer peripheral surface of the guide bush, and a guide hole formed in a member on the plunger mounting side. Is set to be inclined at a predetermined angle with respect to a perpendicular line perpendicular to the axis of the guide bush, and the annular groove is opened to the actual use portion side of the guide hole, while the annular groove is opened to the unused portion side of the guide hole. Offset was made.

In the case of the present invention, even if the guide bush is not positioned in the rotating direction, the communication port is communicated with the actually used portion side of the guide hole, and the unused portion side of the guide hole is closed by the guide bush. Becomes possible.

[0032]

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.

The valve timing control device includes a timing sprocket (not shown) as a driving rotating body which is driven to rotate by a crankshaft (not shown) of an engine, and a housing as a cylindrical member integrally attached to the timing sprocket. 1, a camshaft (not shown) assembled so as to be able to rotate relative to the timing sprocket as needed, and fixed to an end of the camshaft and rotatably housed in the housing 1. Vane body 2, a hydraulic circuit 3 for rotating the vane body 2 forward and reverse by hydraulic pressure, and a vane body associated with a positive rotation fluctuation torque (torque opposite to the rotation direction of the camshaft) acting on the camshaft. And a restricting mechanism 4 for restricting the return of the lock 2.

As shown in FIG. 2, the housing 1 has four partition walls 5 having a trapezoidal cross section projecting from the inner peripheral surface thereof at 90 ° intervals. One side of one of the partition walls 5 is provided. Is provided with a curved concave portion 7 with which the tip of the plunger 6 of the regulating mechanism 4 abuts.

On the other hand, the camshaft is rotatably supported by a cylinder head (not shown), as is well known, and a driving cam for opening an intake valve via a valve lifter at a predetermined position on the outer peripheral surface (both of which are shown in FIG. 1). (Not shown) are integrally provided, and the vane body 2 is connected to a front end by a fixing bolt 8.

The vane body 2 has the fixing bolt 8
Are provided, and four blades 10 radially projecting from the outer peripheral surface of the rotor 9 at intervals of 90 ° are provided. Three of the four blades 10 are formed in a rectangular shape having the same thickness, and the other one is formed in a rectangular shape thicker than these.
Is disposed between the adjacent partition walls 5 and 5 of the housing 1. A seal member 11 that is in close contact with the inner peripheral surface of the housing 1 is fitted and held at the tip of each blade 10, and the rotor of the vane 2 is similarly attached to the tip of each partition 5. A seal member 11 that is in close contact with 9 is fitted and held. A space between one side surface of each vane portion 10 of the vane body 2 and the partition wall portion 5 facing the partition wall portion 5 is an advanced hydraulic pressure chamber 12, and the other side surface of each blade portion 10 and the partition wall portion 5 facing the same. The interval is between the retard hydraulic pressure chambers 13. Therefore, in this device, a total of four pairs of the advance side hydraulic chamber 12 and the retard side hydraulic chamber 13 are provided.

As shown in FIG. 1, the hydraulic circuit 3 sucks and discharges a hydraulic pressure to and from the advance hydraulic chamber 12 and a hydraulic pressure to and from the retard hydraulic chamber 13. There are two hydraulic passages, a second hydraulic passage 15. A supply passage 16 and a drain passage 17 are connected to the two hydraulic passages 14 and 15 via respective electromagnetic switching valves 18 for switching passages. An oil pump 20 for pumping oil in an oil pan 19 is provided in the supply passage 16, and an end of the drain passage 17 communicates with the oil pan 19.

The first hydraulic passage 14 passes from the cylinder head to the inside of the axis of the camshaft and the fixing bolt 8 and further from the annular oil chamber 21 between the rotor portion 9 of the vane body 2 and the head of the fixing bolt 8. Are connected to each advance-side hydraulic chamber 12 through a first suction / discharge hole 22 penetrating through the rotor portion 9 of the vane body 2. On the other hand, the second hydraulic passage 15 passes through the inside of the camshaft from the cylinder head and passes through the housing 1.
Are connected to the retard-side hydraulic chambers 12 through second suction / discharge holes 23 penetrating through the side wall of the valve.

The electromagnetic switching valve 18 has a four-port three
It is of a position type, in which the hydraulic passages 14, 15 and the supply passage 16 and the drain passage 17 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 24 detects the current operating state by a signal from a crank angle sensor for detecting the engine speed and an air flow meter for detecting the intake air amount, and also detects the timing sprocket and the cam by the signals from the crank angle sensor and the cam angle sensor. A relative rotation position with respect to the shaft is detected.

The restricting mechanism 4 is provided with a mounting hole 25 formed in one of the blades 10 having a large thickness of the vane body 2 so as to face the advance hydraulic chamber 13, and is press-fitted and fixed in the mounting hole 25. A guide bush 26; a plunger 6 slidably fitted in the guide bush 26;
A check valve 28 that permits only the flow of hydraulic oil from the pressure chamber 2 into the pressure chamber 27 inside the plunger 6, and a pressure control spool 31 that appropriately opens and closes a connection path 30 that connects the pressure chamber 27 to a low-pressure passage 29 of the vane body 2. And still,
The low-pressure passage 29 of the vane body 2 always communicates with a drain passage (not shown) through a groove (not shown) in the side wall of the housing 1. In this embodiment, the check valve 28 and the pressure control spool 31
A pressure control mechanism that controls the pressure in the plunger 6 (pressure chamber 27) in accordance with the relative rotation control of the vane body 2 with respect to the (cylindrical member).

Here, the housing 1 for accommodating the vane body 2 is formed of an iron-based sintered metal, but the vane body 2 is formed of an alloy such as aluminum or magnesium, or a hard resin for the purpose of weight reduction. Has been
The guide bush 26 press-fitted into the mounting hole 25 of the vane body 2 and the plunger 6 fitted in the guide bush 26 are both formed of a ferrous, highly wear-resistant material such as SCr, SCM, or S. I have. However, since the distal end of the plunger 6 is pressed against the inner surface of the concave portion 7 of the partition wall portion 5 at a high pressure, the surface thereof is further subjected to a heat treatment such as carburizing in order to further improve deformation resistance and wear resistance.

The guide bush 26 is provided in the advance hydraulic chamber 12.
A substantially half of the bottom wall side is press-fitted and fixed in the mounting hole 25 of the vane body 2, and the front end thereof is inserted from the mounting hole 25 into the recess 7 of the partition wall 5.
A predetermined amount protrudes inward.

The plunger 6 has a base end portion accommodated in the guide bush 26 formed in a concave shape, and a space interposed between the concave portion and the bottom of the guide bush 26 serves as the pressure chamber 27. A substantially T-shaped introduction path 33 is formed on the tip end side to communicate the outer peripheral surface with the inside of the pressure chamber 27. At the end of the introduction passage 33 on the pressure chamber 27 side, a check valve 28 that allows only the inflow of hydraulic oil from the advance hydraulic chamber 12 into the pressure chamber 27 is provided. The end of the introduction passage 33 opening to the surface is always in communication with the advance side hydraulic chamber 12. Also,
A spring 35 is interposed between the inner surface of the bottom wall of the guide bush 26 and the plunger 6, and the spring 35 constantly biases the plunger 6 in the protruding direction.

As shown in FIGS. 3 and 5, the base side of the guide bush 26 is formed by reducing the diameter of both the inner peripheral side and the outer peripheral side in steps (hereinafter, this part is referred to as a "reduced diameter wall 36"). The step surface 37 on the inner peripheral side is the plunger 6.
And restricts the displacement of the plunger 6 in the retreating direction. A plurality of through-holes are formed substantially at the center of the reduced-diameter wall 36 in the axial direction, and the through-holes connect the pressure chamber 27 and the low-pressure passage 29 to the connection path 30.
It has been.

A cylindrical pressure control spool 31 is fitted on the outer peripheral surface of the reduced-diameter wall 36 so as to be slidable in the axial direction. It opens and closes appropriately. A flange 38 extends from one end of the outer periphery of the pressure control spool 31. An urging spring 40 is interposed between the flange 38 and the outer peripheral step surface 39 of the guide bush 26. 31, the displacement in the removal direction is
It is regulated by a stopper ring 41 attached to the end of the reduced diameter wall 36. When the hydraulic pressure acting on the outer end surface of the flange portion 38 is small, the pressure control spool 31 opens the connection path 30 by receiving the force of the urging spring 40 as shown in FIG. When the hydraulic pressure acting on the portion 38 increases to a value equal to or greater than the set value, as shown in FIG.

The guide bush 26 is press-fitted and fixed in the mounting hole 25 as shown in FIGS. 1 and 4 in a state where the pressure control spool 31 is assembled on the base side thereof. The side end surface and the outer peripheral surface of the reduced-diameter wall 36 (the space around the connection path 30) communicate with the pressure introduction path 42 and the low-pressure path 29 formed in the vane body 2, respectively. The pressure introduction passage 42 is connected to the annular oil chamber 21 which is a passage on the upstream side of the advance hydraulic chamber 12. Therefore, the pressure of the annular oil chamber 21 acts on the flange portion 38 of the pressure control spool 31, and the pressure control spool 31 receives the force of the spring 40 when the annular oil chamber 21 is in the low pressure state, and connects the connection path 30. When the annular oil chamber 21 becomes high pressure in this state, the oil pressure is displaced in a direction against the spring 40 to close the connection passage 30.

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

At the time of starting the engine and idling,
The electromagnetic switching valve 1 is controlled by a control signal from the controller 24.
8, connects the supply passage 16 with the second hydraulic passage 15 and the drain passage 17 with the first hydraulic passage 14, as shown in FIG. For this reason, the hydraulic pressure pumped from the oil pump 20 is supplied to the retard hydraulic chamber 13 through the second hydraulic passage 15, and the advanced hydraulic chamber 12 is maintained in a low pressure state as when the engine is stopped. Thereby, the blade portion 10 of the vane body 2 is maintained in a state of being rotationally displaced to the maximum in the advance-side hydraulic chamber 12 (in the retard direction) as shown in FIGS.

Accordingly, the relative rotation position between the timing sprocket and the camshaft is held on the retard side, and the opening / closing timing of the intake valve is controlled on the retard side. As a result, the combustion efficiency of the engine is improved, and the engine rotation can be stabilized and the fuel efficiency can be improved.

Here, as shown in FIG. 1, the regulating mechanism 4 has a low hydraulic pressure (drain pressure) acting on the end face of the pressure control spool 31 through the pressure introducing passage 42.
The pressure control spool 31 includes a spring 4 as shown in FIG.
The connection passage 30 is opened by being urged by a force of 0, and the pressure chamber 27 inside the plunger 6 is maintained in a low pressure state. Accordingly, at this time, the plunger 6 abuts the tip end surface against the inner surface of the concave portion 7 of the partition wall portion 5 only by a very weak biasing force of the spring 35, in combination with the fact that the advance side hydraulic chamber 12 is at a low pressure (drain pressure). Let me.

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 18 is operated by the control signal from the controller 24 as shown in FIG. Then, the supply passage 16 communicates with the first hydraulic passage 14, and the drain passage 17 communicates with the second hydraulic passage 15. As a result, the hydraulic pressure in the retard hydraulic chamber 13 is returned from the drain passage 17 to the oil pan 19 through the second hydraulic passage 15 and the pressure in the retard hydraulic chamber 13 becomes low. Is introduced into the advance-side hydraulic chamber 12 through the first hydraulic passage 14, and the blade portion 10 of the vane body 2 is moved in the direction toward the retard-side hydraulic chamber 13 (advance angle) due to a difference between these pressures. Direction).

Therefore, the timing sprocket and the camshaft relatively rotate to the other side, and the opening / closing timing of the intake valve is controlled to the advanced side. The engine output is thereby improved.

When the regulating mechanism 4 is switched from the retard side to the advance side, the first hydraulic passage 14
High-pressure oil is introduced into the advance-side hydraulic chamber 12 through the oil passage, and the high-pressure in the first hydraulic passage 14 acts on the end face of the pressure control spool 31 from the annular oil chamber 21 through the pressure introduction passage 42, so that the advance-side hydraulic pressure is The high-pressure oil in the chamber 12 passes through the introduction path 33 of the plunger 6, opens the check valve 28, and is introduced into the pressure chamber 27. At this time, the pressure control spool 31 receives the oil pressure in the annular oil chamber 21 and changes the connection path 30. Close. For this reason, the plunger 6 advances by an amount corresponding to the amount of the rotation stroke thereof as shown in FIG. 4 with the clockwise rotation of the vane body 2 from the position shown in FIG. 5 is always kept in contact with the inner surface of the recess 7.

Here, the positive fluctuating torque of the camshaft is transmitted to the vane body 2, and when this fluctuating torque tries to rotate the blade section 10 in the counterclockwise direction, the pressure chamber 2
Since the check valve 28 closes the introduction passage 33 due to an increase in the pressure in the pipe 7, the retreat of the plunger 6 is restricted by the hydraulic pressure of the pressure chamber 27 closed by the check valve 28. Therefore, the regulating mechanism 4 controls the vane body 2 by the positive fluctuation torque.
A counter-clockwise rotation causes a so-called projecting force to act, and the projecting force restricts the rotation of the vane body 2 in the counter-clockwise direction. Therefore, the rotation of the vane body 2 in the counterclockwise direction is reliably restricted during rotation from the most retarded side to the most advanced side as shown by a solid line (b) in FIG. Together with this, it rotates quickly in the clockwise direction (advance angle side).

Therefore, the relative rotation speed of the timing sprocket and the camshaft on 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 acts as an assist force for rotating the vane body 2 to the advance side, the control responsiveness of the valve timing is further enhanced.

Further, when the engine operation shifts to the high-speed high-load region, the electromagnetic switching valve 18 is operated to supply the supply passage 16 and the second hydraulic passage 15 and the drain passage 17 and the first hydraulic pressure in the same manner as in the idling operation. The vane body 2 rotates counterclockwise as shown in FIGS. 1 and 2 so that the passages 14 communicate with each other to set the advance hydraulic chamber 12 to a low pressure and the retard hydraulic chamber 13 to a high pressure. Then, the timing sprocket and the camshaft 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, in the regulating mechanism 4, since the pressure introduction passage 42 becomes low pressure and the pressure control spool 31 opens the connection passage 30, the hydraulic oil in the pressure chamber 27 is discharged to the low pressure passage 29 through the connection passage 30. You. As a result, the projecting tension of the plunger 6 is released, the vane body 2 quickly 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 vane body 2 is formed of a material having a low specific gravity such as an aluminum alloy, while the mounting hole 25 of the vane body 2 is formed of the same iron-based material as the plunger 6. Since the guide bush 26 is press-fitted and fixed, and the plunger 6 is slid via the guide bush 26,
Even if the plunger 6 slides by receiving a large moment from the partition wall portion 5 during the rotation control on the advance side, the sliding resistance does not increase extremely at that time, and welding or settling occurs on the sliding portion. Nor. That is, various combinations of the plunger 6 and the mating member sliding with the plunger 6 are conceivable, but as shown in FIG. 6, the combination of iron-based materials is the most excellent in relation between the pressing force and the sliding resistance. Therefore, in the combination of iron-based materials, the sliding resistance does not greatly increase with respect to the increase in the pressing force as compared with other combinations, and there is no fear of welding or sagging.

Therefore, according to this device, the weight of the entire device can be reduced without causing a large increase in the sliding resistance of the plunger 6, and the sliding resistance of the plunger 6 can be kept small. Without setting the force of the spring 35 for urging the plunger 6 large,
The response of the plunger 6 can be enhanced to suppress the generation of abnormal noise. For this reason, compared with the case where the response of the plunger 6 is increased by setting the force of the spring 35 to be large,
The hydraulic pressure required for the retard side rotation control can be reduced, and as a result, the power loss can be further reduced.

Further, the guide bush 2 sliding on each other
Since both the plunger 6 and the plunger 6 are formed of the same iron-based material, the linear expansion coefficients of the plunger 6 and the plunger 6 are the same, and the sliding clearance does not change even if there is a large temperature change. Therefore, the guide bush 26 and the plunger 6
During the rotation control on the advance side, it is possible to always obtain a reliable thrust action by the plunger 6.

In this valve timing control device, the plunger 6 is connected to the guide bush 26 made of an iron-based material.
In addition to the fact that the front end of the guide bush 26 protrudes from the mounting hole 25 of the vane body 2 toward the partition 5 in addition to the support in the above, the moment acting on the support of the plunger 6 from the partition 5 is reduced. Therefore, also from this point, the sliding resistance of the plunger 6 can be reduced. Since the curved concave portion 7 is formed on the partition wall 5 side to avoid interference with the protruding tip portion of the guide bush 26, the rotation angle of the vane body 2 is limited by the guide bush 26. Therefore, a sufficient rotation angle of the vane body 2 can be secured without increasing the size of the entire apparatus.

Further, in the apparatus of this embodiment, the pressure control spool 31 is formed in a cylindrical shape, and the pressure control spool 31 is slidably fitted on the outer peripheral surface of the reduced diameter wall 36 of the guide bush 26. Since the connection passage 30 is opened and closed by sliding the pressure control spool 31, there is no need to secure a space for separately accommodating the pressure control spool 31 in the vane body 2, and therefore, The space occupied by the pressure control spool 31 can be reduced, and the entire apparatus can be made compact. Further, since the pressure control spool 31 is mounted on the outer peripheral surface of the guide bush 26, it is easy to mount the pressure control spool 31 on the guide bush 26. In addition, the pressure control spool 31 is mounted on the guide bush 26 in advance with the bush 26. Since it can be assembled, the assembly of the entire apparatus is also facilitated. Therefore, it is possible to manufacture the entire device at a lower cost from these facts.

In the above description, the case where the rotation of the camshaft is controlled to either the maximum retard position or the maximum advance position with respect to the timing sprocket has been described. Is reached, as shown in FIG.
Is switched to an off position (a position where both the first hydraulic passage 14 and the second hydraulic passage 15 are closed), it is also possible to obtain desired valve timing control.

Next, a second embodiment of the present invention shown in FIGS. 11 to 14 will be described.

The valve timing control device of this embodiment corresponds to claims 5 and 6 of the present invention, and the basic functions of the entire device are the same as those of the first embodiment.
The internal structure of the plunger and the guide bush of the regulating mechanism, and the passage configuration of the peripheral region thereof are different from those of the first embodiment. Note that, in the embodiment described below, the first
The same reference numerals are given to the same portions as those of the embodiment, and the description of the overlapping portions will be omitted. FIGS. 11 and 12 show a state in which control is performed to the most retarded side, and FIGS.
Indicates a state when control is performed to the most advanced side.

The restricting mechanism 104 of this embodiment includes a mounting hole 2 of the vane body 2 into which the guide bush 126 is press-fitted and fixed.
A low pressure passage 29 is connected to the bottom surface of the mounting hole 25, and a pressure introduction hole 50 for introducing a control oil pressure to the pressure control spool 131 is provided on an inner peripheral surface of the mounting hole 25,
In order to guide the same hydraulic pressure as the advanced hydraulic pressure chamber 12 (precisely, the hydraulic pressure on the upstream side of the hydraulic pressure chamber 12), a guide hole 51 is formed in the pressure chamber 27 on the inner side of the pressure chamber 27. The pressure introducing hole 50 and the guide hole 51 are drilled from the outer peripheral surface side of the blade portion 10 of the vane body 2 toward the annular oil chamber 21 on the inner peripheral side of the vane body 2 so that they are parallel to each other. Has been established. Although the advance-side hydraulic chamber 12 is not shown,
As in the first embodiment, it is connected to the annular oil chamber 21 through the first suction / discharge port. Further, the outer end of the pressure introducing hole 50 on the outer side of the blade is closed by a dedicated blind cover 52, but the outer end of the guide hole 51 on the outer side of the blade is not particularly closed by the dedicated blind lid.

The guide bush 126 is provided in the advance hydraulic chamber 1
2 and a thick bottom wall 53 press-fitted and fixed to the bottom of the mounting hole 25,
A spool housing hole 54 is formed in the bottom wall 53 at the base side end surface thereof so as to face the low pressure passage 29 of the vane body 2, and a connection for connecting the low pressure passage 29 to the pressure chamber 27 inside the plunger 106. A passage 130 is formed.
The end of the connection passage 130 on the low pressure passage 29 side is formed by an annular groove 55 formed substantially at the center of the spool accommodation hole 54 in the axial direction. The annular groove 55 and the spool accommodation hole 54 pass through the low pressure passage 29 to the low pressure passage 29. Communicating.

A cylindrical pressure control spool 131 having a bottom is slidably accommodated in the spool accommodation hole 54, and a spring 140 for urging the pressure control spool 131 toward the bottom of the spool accommodation hole 54. Is housed. The pressure control spool 131 uses the spring 1
The annular groove 55 is opened by being urged by 40.

The guide bush 126, which is press-fitted and fixed in the mounting hole 25, has a bottom wall 5 on its outer peripheral surface on the bottom wall 53 side.
A first annular groove 56, a second annular groove 57, and a third annular groove 58 are formed sequentially from the end face side of No. 3 respectively. Of these, the first annular groove 56 is formed relatively wide and the other is narrow, and the second annular groove 57 and the third annular groove 58 are respectively formed with respect to the bottoms of the spool accommodation hole 54 and the plunger accommodation hole 32. They are connected by communication paths 59 and 60. In addition, the third annular groove 58 forms a flow port of the hydraulic oil in the present invention.

Here, the mounting hole 25 of the vane body 2 and the pressure introduction hole 50 and the guide hole 51 are not formed so as to be orthogonal to each other.
1 is set so as to be inclined at a predetermined angle with respect to a perpendicular line perpendicular to the axis of the guide bush 126. The guide bush 126 press-fitted and fixed in the mounting hole 25 is the first bush.
The annular groove 56 and the second annular groove 57 communicate with the pressure introducing hole 50, and the third annular groove 58 communicates with the guide hole 51. At this time, since the first annular groove 56 is formed to be wide, the end of the pressure introducing hole 50 sandwiching the guide bush 126 in the vane body inner direction and the vane body outer direction end are formed in the first annular groove. It is always in communication via 56. For this reason, although the second annular groove 57 partially communicates with the end of the pressure introducing hole 50 in the outward direction of the vane body, the hydraulic oil in the annular oil chamber 21 is reliably introduced. . Therefore, the hydraulic oil in the annular oil chamber 21 is introduced into the bottom of the spool housing hole 54 via the communication passage 59 and the second annular groove 57. Further, since the third annular groove 58 is inclined at a predetermined angle with respect to the guide hole 51, the third annular groove 58 is formed only at the end of the guide hole 51 in the vane body inward direction with the guide bush 126 interposed therebetween. With the end of the vane body outside direction (offset). Therefore, the end of the guide hole 51 in the outward direction of the vane body is closed by the outer peripheral surface of the guide bush 126 where the annular groove 58 does not exist. The hydraulic oil in the annular oil chamber 21 introduced into the third annular groove 58 is further introduced into the pressure chamber 27 through the communication passage 60, but the end of the communication passage 60 on the side facing the pressure chamber 27 side. A check valve 28 that allows only the flow of hydraulic oil from the annular oil chamber 21 in the direction of the pressure chamber 27 is disposed in the section.

Also in this embodiment, the vane body 2 is formed of a material such as an aluminum alloy for weight reduction.
The guide bush 126 is formed of the same iron-based material as the plunger 106 for reducing the sliding resistance of the plunger 106.

Since the valve timing control device has the above-described configuration, it operates almost in the same manner as in the first embodiment in both the advance control and the retard control of the valve timing. However, there is an advantage that the passage for introducing the hydraulic oil into the pressure chamber 27 is easily formed.

That is, in the case of this device, the guide hole 51 drilled from the outer peripheral surface side of the blade portion 10 of the vane body 2 toward the annular oil chamber 21 does not need to be closed with a special blind cover. When the guide bush 126 is press-fitted and fixed in the hole 25, it can be closed by the outer peripheral surface of the guide bush 126. In particular, in the case of this embodiment, the guide hole 51 is set so as to be inclined at a predetermined angle with respect to a perpendicular line perpendicular to the axis of the guide bush 126, while the third annular groove 58 is formed on the outer peripheral surface of the guide bush 126. ,
Since only the end (the actual use side) of the guide hole 51 inside the vane body is communicated with the pressure chamber 27 through the third annular groove 58, the guide hole 126 is not accurately positioned in the circumferential direction, and the guide hole is not accurately positioned. The end (unused portion side) of the outside of the vane 51 can be reliably closed by the outer peripheral surface of the guide bush 126 where the third annular groove 58 does not exist.
Therefore, according to this device, the assembling work at the time of manufacturing becomes easier, and the manufacturing cost can be further reduced.

In the above, 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. Conversely, the vane body is connected to the driving rotary body. 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.

[0076]

As described above, the invention according to claim 1 is
A plunger is slidably attached to either one of the vane and the cylindrical member, and when the vane is controlled to rotate forward or reverse, the hydraulic pressure introduced into the plunger causes the tip of the plunger to be in a cylindrical shape with the vane. By pressing against the member on the other side of the member, the return of the vane body due to the torque reaction force from the engine valve can be regulated, so that the control response of the valve timing can be further improved, and further, the plunger mounting A mounting hole is provided in the side member, a guide bush made of an iron-based material is fitted and fixed in the mounting hole, and the plunger is formed from the same iron-based material as the guide bush.
Because the plunger is slidably housed in the guide bush, even if the vane or cylindrical member is formed of a material having a low specific gravity, such as an aluminum alloy, the plunger or the member supporting the plunger will not be welded or worn. Slipping and the like do not occur, and the sliding resistance of the plunger is reliably reduced over a long period of time.
Therefore, according to the present invention, it is possible to improve the operation response of the plunger without increasing the operating oil pressure, and to reliably prevent the plunger from rattling without increasing the power loss. Become. Further, in the present invention, since the guide bush and the plunger that slide with each other are made of the same material, a change in sliding clearance due to a temperature change does not occur, and operation of the plunger and oil tightness in the plunger are guaranteed. There is also an advantage.

According to the second aspect of the present invention, since the guide bush is fixed to the mounting hole so that its tip protrudes from the mounting hole, the plunger can be securely removed without making the plunger unnecessarily long. In addition, the moment acting on the plunger can be reduced to further reduce the sliding resistance of the plunger.

According to the third aspect of the present invention, since a concave portion is provided on the cylindrical member side to avoid interference with the tip of the guide bush, the vane can be fixed to the cylindrical member without increasing the size of the apparatus. The rotation angle can be increased.

According to the fourth aspect of the present invention, one end of the connection path is formed in the outer peripheral surface on the base side of the guide bush,
The spool is formed in a cylindrical shape, and the spool is fitted on the outer peripheral surface on the base side of the guide bush, and the connection path is opened and closed by sliding of the spool. And the spool itself can be easily assembled.

According to a fifth aspect of the present invention, a hydraulic oil communication port communicating with the inside of the guide bush is formed in the outer peripheral surface of the guide bush, and the member on the plunger mounting side of the vane member and the cylindrical member is formed. A guide hole for hydraulic oil is formed in the guide hole, and the guide bush is fitted and fixed to a member on the plunger mounting side so as to intersect the guide hole, and the communication port communicates with the actual use portion side of the guide hole. In addition, since the unused portion side of the guide hole is closed at a portion other than the distribution port on the outer peripheral surface of the guide bush, it is not necessary to close the end portion of the unused portion side of the guide hole with a dedicated component,
Accordingly, the number of parts can be reduced and the manufacturing cost can be reduced.

According to a sixth aspect of the present invention, the distribution port is
A guide hole formed in an annular groove along the outer peripheral surface of the guide bush and formed in a member on the plunger mounting side,
The guide groove is set so as to be inclined at a predetermined angle with respect to a vertical line perpendicular to the axis of the guide bush, and the annular groove is opened toward the actual use portion side of the guide hole while being offset with respect to the unused portion side of the guide hole. As a result, it is not necessary to position the guide bush in the rotation direction, so that the assembling is further facilitated and the manufacturing cost can be further reduced.

[Brief description of the drawings]

FIG. 1 is a sectional view showing a first embodiment of the present invention.

FIG. 2 is an exemplary sectional view showing the embodiment with parts removed;

FIG. 3 is an enlarged sectional view of a part showing the embodiment.

FIG. 4 is a sectional view showing the same embodiment.

FIG. 5 is an enlarged cross-sectional view of a part showing the same embodiment.

FIG. 6 is a graph showing sliding resistance-pressing force characteristics for each material.

FIG. 7 is a hydraulic circuit diagram showing the first embodiment of the present invention.

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 an enlarged sectional view of a part showing the same embodiment.

FIG. 13 is a sectional view showing the same embodiment.

FIG. 14 is an enlarged cross-sectional view of a component showing the same embodiment.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Housing (cylindrical member) 2 ... Vane body 3 ... Hydraulic circuit 5 ... Partition wall part 6, 106 ... Plunger 7 ... Concave part 10 ... Blade part 12 ... Advance-side hydraulic chamber 13 ... Delay-side hydraulic chamber 25 ... Mounting hole 26, 126 ... guide bush 28 ... check valve (pressure control means) 30, 130 ... connection path 31, 131 ... pressure control spool (pressure control means) 51 ... guide path 58 ... third annular groove (annular groove)

 ────────────────────────────────────────────────── ─── Continuing on the front page (72) Inventor Tamotsu Higashito 1370 Onna, Atsugi-shi, Kanagawa Prefecture F-term in Unisia Gex Co., Ltd. EA12 FA15 GA01 3G092 AA11 DA09 DG02 DG05 DG09 EA28 EA29 FA09 FA14 FA50

Claims (6)

[Claims] 1. A drive rotating body which is driven to rotate 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 by the driving rotator to rotate following the power, at least one of which is fixed to one of the camshaft and the driving rotator and radially extends radially outward from a center of rotation; A vane body having one blade portion, having 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 A hydraulic circuit for sucking and discharging pressure and rotating the vane body forward and reverse with respect to the tubular member; and a slidably mounted one of the vane body and the tubular member slidably, and the vane body attached to the tubular member. For forward / reverse rotation control, the plunger restricts return of the vane body due to torque reaction force from the engine valve by pressing the tip against the other side of the vane body and the cylindrical member by hydraulic pressure introduced inside. And pressure control means for controlling the pressure in the plunger in accordance with the relative rotation control of the vane body with respect to the cylindrical member, wherein a member on the plunger mounting side of the vane body and the cylindrical member is more than the plunger. A valve timing control device for an internal combustion engine formed of a material having a low specific gravity, wherein a mounting hole is provided in the member on the plunger mounting side, and a guide bush made of an iron-based material is fitted into the mounting hole. And, wherein the plunger is formed of the same iron-based material and the guide bush, the guide of an internal combustion engine, characterized in that the plunger has slidably accommodated into the bush valve timing control apparatus. 2. The valve timing control device for an internal combustion engine according to claim 1, wherein the guide bush is fixed to the guide bush such that a tip end protrudes from the mounting hole. 3. The valve timing control device according to claim 2, wherein the guide bush is mounted on the vane body side, wherein a concave portion is provided on the tubular member side to avoid interference with a tip of the guide bush. A valve timing control device for an internal combustion engine. 4. The pressure control means according to claim 1, further comprising a check valve for permitting only the flow of the hydraulic oil into the plunger, and a pressure control spool for opening and closing a connection path communicating the inside of the plunger with the low pressure passage. In the valve timing control device according to any one of the above, one end of the connection path is formed to be open at the base outer peripheral surface of the guide bush, while the spool is formed in a cylindrical shape, and is formed at the base outer peripheral surface of the guide bush. A valve timing control device for an internal combustion engine, wherein the spool is fitted to open and close a connection path by sliding the pool. 5. A hydraulic oil communication port communicating with the guide bush is formed in an outer peripheral surface of the guide bush, and a hydraulic oil guide hole is formed in a member of the vane body and the cylindrical member on a plunger mounting side. The guide bush is fitted and fixed to a member on the plunger mounting side so as to cross the guide hole, and the communication port communicates with the actual use portion side of the guide hole, and the guide hole is not used. The valve timing control device for an internal combustion engine according to any one of claims 1 to 4, wherein the portion is closed at a portion other than the communication port on the outer peripheral surface of the guide bush. 6. The distribution port is formed by an annular groove along the outer peripheral surface of the guide bush, and the guide hole formed in the member on the plunger mounting side is inclined at a predetermined angle with respect to a perpendicular line perpendicular to the axis of the guide bush. 6. The internal combustion engine according to claim 5, wherein the annular groove is set so as to open toward the actual use portion side of the guide hole while being offset with respect to the unused portion side of the guide hole. Valve timing control device.