JP2002054407A - Valve timing control device for internal combustion engine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To surely prevent deformation when a guide bush is machined or assembled for providing smooth actuation of a lock pin. SOLUTION: In this valve timing control device comprising the lock pin 34 provided on a vane member 7 to be freely capable of advancing and retracting of which the tip is engaged with the guide bush 41 installed on a side wall of a housing member 5 for regulating relative rotation between the vane member 7 and the housing member 5, a bottom wall 43 is formed at one end of a circumferential wall part 42 of the guide bush 41. The circumferential wall part 42 is reinforced by the bottom wall 43, thereby the circumferential wall 42 is not deformed when the guide bush 41 is machined to be finished, or fitted into an installation hole 40.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION The present invention relates to an internal combustion engine (hereinafter referred to as "internal combustion engine").
Let's say "engine". The present invention relates to a valve timing control device for controlling the opening / closing timing of the intake valve and the exhaust valve according to the operating conditions.

[0002]

2. Description of the Related Art An intake valve and an intake valve are rotated by rotating an assembling angle between a driving force transmitting member such as a timing pulley or a chain sprocket which rotates synchronously with an engine crankshaft and a camshaft having a driving cam on the outer periphery. 2. Description of the Related Art A valve timing control device for variably controlling the opening / closing timing of an exhaust valve has been proposed in the related art.

In the valve timing control device described in this publication, a vane member integrally attached to an end of a camshaft is accommodated and arranged inside a housing member integrated with a driving force transmitting member, and the vane member is arranged inside the housing member. An advance hydraulic chamber and a retard hydraulic chamber are provided, and the vane member is rotated relative to the housing member by selectively absorbing and discharging hydraulic pressure in each of the hydraulic chambers. The opening / closing timing of the intake valve and the exhaust valve is changed by changing the rotation phase of the intake valve and the exhaust valve.

In such a so-called vane type valve timing control device, when the supply hydraulic pressure is low, for example, when the rotation speed of the engine is low, the pressure in the hydraulic chamber loses the reaction force received from the intake valve and the exhaust valve, and the vane It is known that a member is pushed by its reaction force. In order to cope with this, in the valve timing control device described in the above publication, a lock pin is provided on the vane member and the housing member as a rotation restricting means for fixing a relative position between the vane member and the housing member. To prevent pushing back.

That is, the lock pin is attached to the vane member so as to be able to advance and retreat in a state of being biased by a spring. When the relative rotation of the vane member and the housing member is controlled in the set direction,
When the tip of the lock pin is fitted into a lock hole provided in the inner wall of the housing member to lock the relative rotation between them, and from this state, the relative rotation of the vane member and the housing member is controlled in the opposite direction. High-pressure hydraulic oil is introduced into the bottom of the lock hole to release the engagement of the lock pin.

[0006]

The lock hole into which the tip of the lock pin is fitted when restricting the relative rotation of the vane member and the housing member receives a large load input from the lock pin in the fitted state. Therefore, it is formed separately from the housing member by a material having high wear resistance. Specifically, the lock hole is formed by a cylindrical guide bush made of a material having high wear resistance, and this guide bush is press-fitted and fixed to a mounting hole in an inner wall of the housing member.

The inner peripheral surface of the guide bush forming the lock hole is required to have high dimensional accuracy in order to realize the smooth operation of the lock pin. Usually, after being formed into a cylinder, it is accurately tightened and fixed to a processing jig. Finishing processing such as cutting and polishing is performed.

However, in the conventional valve timing control device, since the guide bush is cylindrical, there is a possibility that the guide bush will be deformed when it is fastened and fixed to a jig. There is a concern that the bush may be deformed even when press-fitting. If the guide bush is deformed during machining or assembling, the intended purpose of achieving smooth operation of the lock pin cannot be achieved.

Accordingly, the present invention is to provide a valve timing control device for an internal combustion engine which can reliably prevent deformation of a guide bush during machining or assembly, and can obtain a smooth operation of a lock pin. To do.

[0010]

SUMMARY OF THE INVENTION In order to solve this problem, an invention according to claim 1 is a driving force transmitting member driven by a crankshaft of an internal combustion engine, and a driving force for operating an engine valve on an outer periphery. A camshaft having a cam, the driving force transmitting member being assembled so as to be able to rotate relative to one another as needed, and receiving a power from the driving force transmitting member to be driven to rotate, the driving force transmitting member and the camshaft; A housing member that rotates integrally with one of the housing member, a vane member that is housed in the housing member, and rotates integrally with the other of the driving force transmission member and the camshaft, and a housing member that rotates inside the housing member. An advance hydraulic chamber and a retard hydraulic chamber for rotating the vane member by hydraulic pressure, and communicating with the advance hydraulic chamber and the retard hydraulic chamber; Hydraulic suction means for selectively sucking and discharging hydraulic pressure in the pressure chamber, a guide bush fitted and fixed to a set position of a side wall of the housing member, and mounted on the vane member so as to be able to advance and retreat, according to an operation state of the internal combustion engine. In the valve timing control device for an internal combustion engine, comprising: a lock pin that is fitted to or released from the guide bush, a bottom wall is formed at one end of the peripheral wall of the guide bush.

In the case of the present invention, the peripheral wall of the guide bush is reinforced by the bottom wall, so that the peripheral wall is less likely to be deformed during processing or assembly.

According to a second aspect of the present invention, a mounting hole is formed at a set position of the side wall of the housing member so as to penetrate the side wall, and a guide bush is press-fitted and fixed in the mounting hole and mounted by the bottom wall of the guide bush. The holes were closed.

In the case of the present invention, when the guide bush is pressed into the mounting hole of the housing member, since the bottom of the mounting hole is not closed, the peripheral area of the mounting hole is easily extended and deformed. Therefore, local deformation such as swelling is less likely to occur on the peripheral edge of the mounting hole near the vane member.

According to a third aspect of the present invention, a suction and discharge hole for sucking and discharging hydraulic oil acting on the tip of the lock pin when the lock pin and the guide bush are fitted is formed through the peripheral wall of the guide bush.

In the case of the present invention, the suction and discharge holes do not occupy the thickness direction of the housing member. When the suction and discharge holes are formed in the peripheral wall of the guide bush by drilling or the like, the deformation is prevented by the bottom wall.

[0016]

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

1 to 3 show an embodiment of the present invention. In FIG. 1, reference numeral 1 denotes a camshaft on the intake side of an engine. The camshaft 1 is rotatably supported by a cylinder head (not shown) via a bearing, and a drive cam (not shown) for opening and closing an intake valve as an engine valve is provided on an outer periphery of a main portion thereof. I have. The valve timing control device 2 according to the present invention includes the camshaft 1
At one end.

The valve timing control device 2 includes a chain sprocket 4 as a driving force transmitting member that is rotationally driven by a crankshaft via a timing chain (not shown), and the chain sprocket 4 is formed on the outer periphery on the rear side. A housing member 5, the camshaft 1 assembled at one end so that the housing member 5 can rotate as required, and the camshaft 1.
A vane member 7 integrally mounted on one end of the housing member 5 and rotatably housed inside the housing member 5; a hydraulic suction / discharge means 8 for rotating the vane member 7 forward and reverse by hydraulic pressure according to the operating state of the engine; A rotation restricting means 9 is provided for restricting return of the vane member 7 due to rotational fluctuation torque acting on the camshaft 1 in accordance with an operation state.

The housing member 5 includes a substantially cylindrical housing body 10 and a front cover 12 connected to front and rear end faces of the housing body 10 by bolts 11.
And a rear cover 13, and the housing body 10
As shown in FIG. 2, four partition walls 14 each having a trapezoidal cross section protrude from the inner peripheral surface at intervals of approximately 90 °.

On the other hand, the vane member 7 is connected to the camshaft 1 by bolts (not shown), and has a substantially cylindrical body 1.
6 and four blades 17 radially protruding from the outer peripheral surface of the body 16 at substantially 90 ° intervals.
6 is disposed at the axial center position of the housing member 10, and each blade 17 is connected to the adjacent partition wall 14, 14 of the housing member 5.
It is located between them. An advancing hydraulic chamber 18 is provided between one side surface of each blade portion 17 of the vane member 7 and the partition wall 14 facing the same, and the other side surface of each blade portion 17 and the partition wall 14 facing the partition wall 14 are opposed to each other. The interval is defined as a retard hydraulic chamber 19. Therefore, in this device, the advance hydraulic chamber 1
8 and the retard hydraulic chamber 19 are provided in total of four pairs. still,
A spring-biased seal member 20 is mounted on each of the blades 17 and the tip of the partition wall 14, respectively.
Liquid tightness between 8 and 19 is achieved.

A circular recess 21 is provided on the front side of the body 16 of the vane member 7, and an end of a first radial hole 22 communicating with each of the advance hydraulic chambers 18. The ends of the second radial holes 23 communicating with the retard hydraulic chamber 19 are respectively opened in the inner peripheral surface of the recess 21. Each end of the first radial hole 22 and the second radial hole 23 opens at a position in the recess 21 that is offset in the axial direction.

A cylindrical shaft member 24 extending from a front cover (not shown) of the engine is fitted in the concave portion 21 of the vane member 7 so as to be relatively rotatable. Hydraulic oil is sucked and discharged from the advance hydraulic chamber 18 and the retard hydraulic chamber 19.

As shown in FIG. 1, the hydraulic suction / discharge means 8 includes a first hydraulic passage 2 for sucking / discharging hydraulic pressure with respect to the advance hydraulic chamber 18.
5 and a second hydraulic passage 26 that sucks and discharges hydraulic pressure to and from the retard hydraulic chamber 19.
A supply passage 27 and a drain passage 28 are respectively connected to 5 and 26 via an electromagnetic switching valve 29 for switching the passage. An oil pump 31 for feeding oil in the oil pan 30 is provided in the supply passage 27, and an end of the drain passage 28 communicates with the oil pan 30. The electromagnetic switching valve 29 is controlled by a controller 32. Various signals indicating the operating state of the engine are input to the controller 32.

The rotation restricting means 9 mechanically controls the relative rotation between the housing member 5 and the vane member 7 when the rotation of the vane member 7 is controlled to the retard side when the engine is started. A lock pin 34 is housed and supported by the vane member 7 so as to be able to advance and retreat in the axial direction, and the lock pin 34 projects in the protruding direction (toward the front cover 12).
A spring member 35 biasing the front cover 12 and an inner surface of the front cover 12 (an inner wall of the housing member 5).
A lock hole 36 into which the tip of the lock pin 34 is fitted at a position where the vane member 7 is maximally displaced toward the retard side with respect to the housing member 5 is provided.

The lock pin 34 has a tapered portion 34a at its tip.
And is slidably received via a collar 38 in a shaft hole 37 formed in one blade 17 a of the vane member 7. The shaft hole 37 accommodates the spring member 35 for urging the lock pin 34 in the projecting direction and a spring support pin 39 for supporting one end of the spring member 35. The back space communicates with the atmosphere.

On the other hand, the lock hole 36 is
Instead of being directly processed on the front cover 12
Mounting hole 4 that penetrates the cover 12 in the axial direction at the set position
0 is formed, and a cylindrical guide bush 41 having a bottom and made of a material having high wear resistance is press-fitted and fixed in the mounting hole 40. Guide bush 41
Has a peripheral wall portion 42 having a tapered inner peripheral surface into which the tip of the lock pin 34 is fitted, and a bottom wall 43 closing one end of the peripheral wall portion 42. In the vicinity, a suction / discharge hole 44 for sucking / discharging hydraulic oil acting on the tip of the lock pin 34 when the lock pin 34 is fitted is formed along the radial direction.

As described above, the lock hole 36 is formed by the inner peripheral surface of the peripheral wall portion 42, and the mounting hole 40 of the front cover 12 is closed by the bottom wall 43 of the guide bush 41. The suction / discharge hole 44 of the guide bush 41 communicates with the advance hydraulic chamber 18 via a guide groove 45 formed in the front cover 12.

In this structure, when hydraulic oil is not sufficiently supplied from the oil pump 31 when the engine is started, or when high-pressure hydraulic oil is supplied to the retard hydraulic chamber 19 by operating the electromagnetic switching valve 29, the vane member 7 is at the most retarded position shown in FIG. 2 with respect to the housing member 5, and the lock pin 34 of the rotation restricting means 9
Of the guide bush 41 is fitted into the lock hole 36 of the guide bush 41, and the vane member 7 and the housing member 5 are mechanically connected. Therefore, the rotational driving force input to the chain sprocket 4 from a crankshaft (not shown) is transmitted to the camshaft 1 via the housing member 5 and the vane member 7 which are mechanically connected in the most retarded state,
The intake valve is opened and closed at a retard timing through a drive cam (not shown).

When the vane member 7 is rotationally displaced to the most retarded side, the lock pin 34 mechanically couples the housing member 5 and the vane member 7 as described above. Even when the fluctuation torque is input to the camshaft 1 from the above, the vane member 7 does not rotate relative to the housing member 5, and therefore, there is no problem such as the rattling noise of the vane member 7.

In this state, the advance hydraulic chamber 18 communicates with the supply passage 27 and the retard hydraulic chamber 19 communicates with the drain passage 28 under the control of the electromagnetic switching valve 29 by the controller 32. High-pressure hydraulic oil is introduced into the chamber 18, and at this time, the high-pressure hydraulic oil is also introduced into the distal end portion (lock hole 36) of the lock pin 34 through the guide groove 45 and the suction / discharge hole 44. At this time, the lock pin 34 receives the pressure of the high-pressure hydraulic oil, retreats against the urging force of the spring member 35, and releases the rotation regulation of the housing member 5 and the vane member 7.

On the other hand, each blade portion 17 of the vane member 7 receives a differential pressure between the advance hydraulic chamber 18 and the retard hydraulic chamber 19, and the entire vane member 7 is advanced with respect to the housing member 5 in the advance direction (the retard hydraulic chamber). 19) and stops at the most advanced position. Thereby, the chain sprocket 4 and the camshaft 1 rotate relatively, and the rotation phase of the camshaft 1 with respect to the chain sprocket 4 is controlled to the advanced side.

In this way, while the rotation phase of the camshaft 1 with respect to the chain sprocket 4 is controlled to the advance side, the high pressure of the oil pump 31 continues to act on the advance hydraulic chamber 18. As a result, it is maintained in a state retracted in the cylinder hole 44.

The valve timing control device 2 operates as described above. However, the guide bush 41 into which the lock pin 34 is fitted has the bottom wall 43 integrally provided at the end of the peripheral wall portion 42. Strong in strength and hardly deformed in the radial direction in response to external load input. Therefore, the peripheral wall portion 42 is not deformed by the tightening force when the bush 41 is fastened and fixed to the processing jig at the time of finishing the guide bush 41, so that a highly accurate finishing process can be realized. it can. Also, when the guide bush 41 is press-fitted and fixed in the mounting hole 40 of the front cover 12, the deformation does not similarly occur, so that the accuracy of the inner peripheral surface of the guide bush 41 is maintained even in the assembled state.

Further, the mounting hole 40 is provided in the front cover 12.
When the guide bush 41 is pressed into the mounting hole 40, deformation such as swelling does not occur at the periphery of the mounting hole 40.

That is, as another embodiment of the present invention, as shown in FIG. 4, a mounting hole 50 which does not penetrate the front cover 12 is provided on the inner surface of the front cover 12, and a guide bush 41 is press-fitted into the mounting hole 50. Although a fixing structure can be adopted, in the case of the embodiment shown in FIG. 4, when the guide bush 41 is pressed into the mounting hole 50, the extension of the peripheral area of the mounting hole 50 is restricted by the bottom wall 50 a. As the elongation is restricted, a bulge 51 as shown in FIG. However, as in the embodiment shown in FIGS. 1 to 3, a mounting hole 40 that completely penetrates the front cover 12 in the thickness direction is provided, and the guide bush 41 is pressed into the mounting hole 40. Sometimes mounting holes 40
Is relatively easy to extend, and as shown in FIG.
Deformation such as swelling does not occur on the periphery of the zero.

Therefore, since the peripheral edge of the mounting hole 40 is not deformed, which is likely to cause a hook or the like, the operation of the lock pin 34 is smooth and reliable.

In the embodiment shown in FIGS. 1 to 3, since the mounting hole 40 formed in the front cover 12 is closed by the bottom wall 43 of the guide bush 41, the mounting hole 50 ( 4 and 5), and the front cover 12 is made thinner by the bottom wall 50a of the mounting hole 50 as compared with press-fitting the guide bush 41 into the hole 50. There is an advantage that it can be achieved.

Further, in any of the above-described embodiments, since the suction / discharge hole 44 is formed in the peripheral wall portion 42 instead of the bottom wall 43 of the guide bush 41, the thickness of the bottom wall 43 is reduced to form the suction / discharge hole. The front cover 12 can be made thinner by not having to make it thicker. When the suction and discharge holes 44 are formed in the peripheral wall portion 42 of the guide bush 41, the peripheral wall portion 42 of the bush 41 is machined by, for example, drilling from the radial direction. Thus, since it is reinforced by the bottom wall 43, there is almost no deformation accompanying the drilling.

[0039]

As described above, the invention described in claim 1 is
Since the peripheral wall of the guide bush can be reinforced by the bottom wall formed at one end thereof, deformation of the guide bush during processing and assembly of the guide bush can be reliably prevented, and smooth operation of the lock pin is always obtained. Can do.

According to the second aspect of the present invention, when the guide bush is press-fitted into the housing member, local deformation such as swelling at the periphery of the mounting hole of the housing member can be prevented, so that the lock pin and the guide bush are fitted. At the time of mating or disengagement, the lock pin does not get caught on the deformed portion, so that a stable and reliable operation of the lock pin can be obtained.

According to the third aspect of the present invention, since the suction / discharge passage does not occupy the thickness direction of the housing member, the size and weight of the housing member can be reduced.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view of one embodiment of the present invention, taken along line AA of FIG.

FIG. 2 is an exemplary sectional view of the embodiment, taken along line BB of FIG. 1;

FIG. 3 is a partially enlarged cross-sectional view showing the same embodiment.

FIG. 4 is a sectional view showing another embodiment of the present invention.

FIG. 5 is an enlarged sectional view of a part of FIG. 4 showing the same embodiment;

[Explanation of symbols]

 2 ... Valve timing control device 4 ... Chain sprocket (driving force transmitting member) 5 ... Housing member 7 ... Vane member 8 ... Hydraulic suction / discharge means 18 ... Advance hydraulic chamber 19 ... Delay hydraulic chamber 34 ... Lock pin 40 ... Mounting hole 41 ... Guide bush 42 ... Peripheral wall 43 ... Bottom wall 44 ... Suction and discharge hole

Claims (3)

[Claims] 1. A driving force transmitting member driven by a crankshaft of an internal combustion engine, and a driving cam for operating an engine valve on an outer periphery, so that the driving force transmitting member can be relatively rotated as required. A camshaft that is assembled and driven to rotate by receiving power from the driving force transmission member, a housing member that rotates integrally with one of the driving force transmission member and the camshaft, A vane member housed and rotating integrally with the other of the driving force transmission member and the camshaft; an advance hydraulic chamber and a retard hydraulic pressure provided in the housing member and rotating the vane member by hydraulic pressure A hydraulic suction / discharge means communicating with the advance hydraulic chamber and the retard hydraulic chamber, and selectively absorbing and discharging hydraulic pressure to and from these hydraulic chambers; A guide bush fitted and fixed at a set position of a side wall of the member; a lock which is attached to the vane member so as to be able to advance and retreat, and which is fitted to or released from the guide bush according to an operation state of the internal combustion engine. A valve timing control device for an internal combustion engine, comprising: a pin; and a bottom wall formed at one end of a peripheral wall portion of the guide bush. 2. A mounting hole penetrating through the side wall of the housing member at a set position of the side wall, and a guide bush is press-fitted and fixed in the mounting hole, and the mounting hole is closed by a bottom wall of the guide bush. The valve timing control device for an internal combustion engine according to claim 1, wherein 3. The guide bush according to claim 1, wherein a suction / discharge hole for sucking / discharging hydraulic oil acting on a tip of the lock pin when the lock pin and the guide bush are fitted is formed through the peripheral wall of the guide bush. A valve timing control apparatus for an internal combustion engine according to claim 1.