JPH10238319A - Valve timing control device for internal combustion engine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent generation of strike noise resulting from collision of the vane of a rotor with the oil pressure chamber of a housing during lowering of an amount of oil in an oil pressure chamber, in a vane type valve timing control device. SOLUTION: Oil retaining holes 14a and 14b are formed in the outermost part of wall surfaces 12a and 12b forming a contact surface in each vane chamber 12 of a housing 7. Meanwhile, protrusion parts 15a and 15b fitted in protrusion parts 15a and 15b with a slight clearance therebetween are formed on sides 10a and 10b forming a contact surface in each vane 10. When the vane 10 collides with a housing 7, the protrusion parts 15a and 15b enter the oil reservoir holes 14a and 14b and is about to compress oil therein. In this case, oil escapes through the slight clearance and a speed of collision between the vane 10 and the housing 7 is relaxed. As a result, an impact during collision, the generation of strike noise is prevented.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a valve timing control apparatus for continuously changing the timing of opening and closing an intake valve or an exhaust valve in an internal combustion engine (engine), and more particularly to a so-called vane type valve timing control. Related to the device.

[0002]

2. Description of the Related Art Conventionally, various variable mechanisms of a valve train have been put to practical use in an automobile engine in order to achieve an optimal valve timing according to an operating state. The main type of such a variable mechanism is a two-stage switching type, that is, an ON / OFF control type.
In recent years, such a variable valve timing mechanism (hereinafter also referred to as a VVT mechanism) has been constantly optimized instead of a conventional two-stage switching type in order to meet the demand for higher performance of the engine. A continuously variable type that can set any arbitrary valve timing is being developed. In an internal combustion engine having a variable valve timing mechanism, in view of contributing intake efficiency to the improvement of the output performance, and contributes to the improvement of the fuel economy due to a reduction in improved and pumping loss of the exhaust gas purification performance (emission) due to the reduction of the NO _x From the viewpoint of internal exhaust gas recirculation (internal EGR), the valve timing is controlled according to the engine operating state.

[0003] For example, Japanese Patent Application Laid-Open No. 8-121122 discloses a so-called vane type VVT mechanism. This vane type V
In the VT mechanism, a housing that is drivingly connected to a crankshaft and has a concave portion on an inner peripheral surface,
A camshaft having a vane partitioned into two hydraulic chambers and being combined with the housing so as to be rotatable relative to each other. It has a structure in which the valve timing is continuously changed by shifting the phase.

[0004]

When the internal combustion engine is stopped for a long time, the hydraulic oil in each of the hydraulic chambers (the advance hydraulic chamber and the retard hydraulic chamber) falls off. Due to this dropout, there is a problem that when the internal combustion engine is restarted, each vane collides with the wall surface of the retard hydraulic chamber and a tapping sound is generated. More specifically, when the internal combustion engine is stopped and the operating oil drops, the relative rotation angle position of the camshaft with respect to the housing is such that the volume of the advance hydraulic chamber is the smallest and the volume of the retard hydraulic chamber is the largest. Position, that is, the most retarded position. From this state, the operating oil is supplied to the advance hydraulic chamber when the internal combustion engine is started.
Since the retard hydraulic chamber is not filled with oil, the vane collides with the wall surface of the retard hydraulic chamber and a loud tapping sound is generated.

[0005] Also, during turning operation of the vehicle, a large amount of air enters the oil, and the oil in the advance hydraulic chamber and the retard hydraulic chamber is reduced. In some cases, the vane collides with the wall surface of the hydraulic chamber, and a tapping sound is generated.

In view of the above circumstances, an object of the present invention is to provide a first rotating body having a concave portion on an inner peripheral surface and a second rotating body having at least one of the two chambers having a hydraulic chamber for partitioning the concave portion. The first rotating body and the second rotating body are relatively rotated by controlling the hydraulic pressure supplied to the hydraulic chamber by providing the rotating body of the crankshaft coaxially with the rotating body of the crankshaft for driving one of the rotating bodies. In a vane type valve timing control device having a structure in which the rotation phase of a camshaft interlocked with the other rotating body is shifted with respect to the rotating phase, the first rotating body and the second rotating body are separated when the amount of fluid in the hydraulic chamber decreases. An object of the present invention is to prevent a situation in which a hitting sound is generated due to a collision due to a torque fluctuation of a camshaft with a simple structure.

[0007]

A valve timing control device for an internal combustion engine according to a first aspect of the present invention, which has been devised to achieve the above object, has at least one concave portion on an inner peripheral surface. A first rotating body rotatably provided about a rotating shaft, and at least one of the first rotating body and the second rotating body as a hydraulic chamber.
A second rotating body that has at least one vane defining the recess in one of the chambers and that is rotatably provided coaxially with the rotating shaft; and one of the first rotating body or the second rotating body. And a camshaft that rotates in conjunction with the other of the first rotating body or the second rotating body to drive a valve, and is supplied to the hydraulic chamber according to an engine operating state. Control means for relatively rotating the first rotator and the second rotator about the rotation axis by controlling the amount of liquid flowing therethrough,
In the valve timing control device for an internal combustion engine, a contact surface of the first rotating body and a contact surface of the second rotating body that constitute a wall surface of the hydraulic pressure chamber and can abut against each other by the relative rotation. A fitting portion capable of fitting with a predetermined clearance to the contact surface is provided.

[0008] According to a second aspect of the present invention, in the valve timing control device for an internal combustion engine according to the first aspect of the present invention, the fitting portion is the most abutting surface on the contact surface relative to the rotary shaft. It is provided on the outer part.

In the valve timing control apparatus for an internal combustion engine according to the first aspect of the present invention, the amount of liquid in the hydraulic chamber is small, and the first rotating body is caused by torque fluctuation of the camshaft. Even when the second rotating body collides with the second rotating body at the contact surface, the collision is mitigated by the damper effect of the liquid staying in the fitting portion, and the generation of a tapping sound is prevented. Further, in the device according to the second aspect of the present invention,
Since the fitting portion is provided at the outermost portion of the rotating shaft, even when the amount of liquid is small, the liquid easily stays in the fitting portion due to the centrifugal force, and the above-described damper effect can be increased.

[0010]

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

FIG. 1 is a front sectional view of a valve timing control device 1 according to an embodiment of the present invention, FIG. 2 is a sectional view taken along line AA in FIG. 1, and FIG. It is an expanded sectional view of the fitting part provided in the contact surface with a vane chamber. The valve timing control device 1 is mounted on a vehicle engine that employs DOHC as a valve drive system.

As shown in FIG. 2, the valve timing control device 1 is provided at an end of an intake camshaft 3 supported by a cylinder head 2. The valve timing control device 1 includes a side plate 5, a rotor 6, a housing 7, a cover 8, and the like.

The side plate 5 is formed in a disk shape and is fixed to a flange 3 a provided at an end of the intake side camshaft 3. A boss 5a is formed on the side plate 5 so as to project therefrom.
Is fixed to the rotor 6.

As shown in FIG. 1, the rotor 6 has a boss 5a.
A cylindrical shaft portion 9 is fitted on the outer surface of the shaft portion.
The vanes 10 are provided at equal angular intervals. Each vane 1
0 is formed in a fan shape that expands toward the outer peripheral side.

As shown in FIG. 2, a cylindrical housing 7 is slidably fitted on the outer peripheral surface 5b of the side plate 5. The housing 7 includes a hole 11 that can accommodate the shaft portion 9 of the rotor 6, and three vane chambers 12 that can accommodate the respective vanes 10 on the outer peripheral side of the hole 11. Each vane chamber 12 is formed in a fan shape that expands toward the outer peripheral side. The shaft 9 is slidably fitted in the hole 11, and each vane 10 is accommodated in each vane chamber 12 so as to be relatively movable in the rotation direction with the rotation of the shaft 9. That is, the inner peripheral surface of the partition 13 formed between the vane chambers 12 is in sliding contact with the outer peripheral surface of the shaft 9. on the other hand,
The outer peripheral surface of each vane 10 is in sliding contact with the inner peripheral surface of each vane chamber 12 in which each vane 10 is stored. Accordingly, the rotor 6 and the housing 7 are relatively rotatable relative to each other by an angle by which each vane 10 can relatively move in the rotation direction in the vane chamber 12.

In FIG. 1, when the rotor 6 is rotated clockwise relative to the housing 7, each vane 10 is rotated.
The clockwise side surface 10a and the clockwise wall surface 12a of each vane chamber 12 finally contact. The rotor 6
Is rotated relative to the housing 7 in the counterclockwise direction, the counterclockwise side surface 10b of each vane 10 and the counterclockwise wall surface 12b of each vane chamber 12 finally contact. That is, in the present embodiment, the side surfaces 10a, 10a
b and the wall surfaces 12a and 12b are contact surfaces.

External teeth 7b are provided on an outer peripheral surface 7a of the housing 7, and a timing chain 4 which is drivingly connected to a crank pulley (not shown) is mounted on the external teeth 7b.

As shown in FIG. 2, a cover 8 for sealing the vane chambers 12 of the housing 7 is fixed to an end face of the housing 7. The side plate 5, the rotor 6, the housing 7, and the cover 8 are attached to the end of the intake camshaft 3 by bolts 18 penetrating the members 5, 6, 7, and 8. That is, the housing 7 and the cover 8 are supported so as to be relatively rotatable with respect to the side plate 5 and the rotor 6.

As shown in FIG. 1, in each vane chamber 12, two hydraulic chambers 19, 20 are defined by each vane 10. That is, in each vane chamber 12, an advance hydraulic chamber 19 is formed on the counterclockwise side of each vane 10, and a retard hydraulic chamber 20 is formed on the clockwise side of each vane 10.

Here, when the volume of each advance hydraulic chamber 19 increases and the volume of each retard hydraulic chamber 20 decreases, that is, each vane 10 moves to the retard hydraulic chamber 20 side in each vane chamber 12. Then, the rotor 6 with respect to the housing 7
Is adjusted in the advance direction. Conversely, when the volume of each retard hydraulic chamber 20 increases and the volume of each advance hydraulic chamber 19 decreases, that is, when each vane 10 moves toward the advance hydraulic chamber 19 in the vane chamber 12, the housing 7 Is adjusted in the retard direction.

As shown in FIG. 2, the intake side camshaft 3
An oil passage 21 for an advance angle and an oil passage 22 for a retard angle are provided in a bearing portion 2a of the cylinder head 2 on which is supported. Each of the oil passages 20 and 21 has an engine electronic control unit (ECU) 3
Oil control valve (OCV) controlled by 5
(Direction control valve) 23 is connected. Oil pump 3
The hydraulic oil pumped from oil pan 37 by O
When supplied to the advance oil passage 21 by the CV 23,
At the same time, hydraulic oil is discharged from the retard oil passage 22 to the oil pan 37. Conversely, when the hydraulic oil pumped up from the oil pan 37 by the oil pump 36 is supplied to the retard oil passage 22 by the OCV 23, the advance oil passage 2
Hydraulic oil is discharged from 1 to the oil pan 37. ECU3
5 controls the OCV 23 according to the operating state of the engine.

The advancing oil passage 21 communicates with an oil passage 25 formed inside the intake camshaft 3 via an oil groove 24 on the cylinder head 2 side. The oil passage 25 communicates with an annular oil passage 27 formed between the bolt 18, the boss 5 a, and the shaft 9 through a notch 26 formed in the side plate 5 from the end of the intake-side camshaft 3. I have. The oil passage 27 communicates with each of the advance hydraulic chambers 19 through three oil grooves 28 formed on the distal end surface of the shaft portion 9.

On the other hand, the retarding oil passage 22 communicates with an oil passage 30 formed inside the intake camshaft 3 through an oil groove 29 on the cylinder head 2 side. The oil passage 30 has an oil hole 3 formed in the side plate 5 from the end of the intake side camshaft 3.
1 communicates with an annular oil passage 32 formed between the shaft portion 9 and the boss 5a. The oil passage 32 is formed in each of the retard hydraulic chambers 20 by three oil grooves 33 formed on the base end side of the shaft portion 9.
Is in communication with

Accordingly, the OCV 23 allows the advance oil passage 2
When the hydraulic oil is supplied to 1 and the hydraulic oil is discharged from the retard oil passage 22, the hydraulic oil is supplied to each advance hydraulic chamber 19 and the hydraulic oil is discharged from each retard hydraulic chamber 20. Then, the relative rotation phase of the rotor 6 with respect to the housing 7 is adjusted in the advance angle direction. As a result, the relative rotation phase of the intake side camshaft 3 with respect to the crankshaft is adjusted to the advance side. Conversely, when hydraulic oil is supplied to the retard oil passage 22 and hydraulic oil is discharged from the advance hydraulic passage 21, hydraulic oil is supplied to each retard hydraulic chamber 20 and each advance hydraulic chamber 19
The hydraulic oil is discharged from the. Then, the relative rotational phase of the rotor 6 with respect to the housing 7 is adjusted in the retard direction. As a result, the relative rotation phase of the intake side camshaft 3 with respect to the crankshaft is adjusted to the retard side.

The valve timing control device 1 is driven to rotate clockwise by the crankshaft, and accordingly, the intake camshaft 3 is driven to rotate in the same direction. And
The intake camshaft 3 drives an intake valve via an intake cam (not shown).

As described above, when the engine is started, each advance hydraulic chamber 19 and each retard hydraulic chamber 20
Each of the vanes 10 moves abruptly in the advance direction in a state where the hydraulic oil is not filled, and the side surface 10 a of the vane 10 on the retard hydraulic chamber 20 side faces the side wall 12 of the retard hydraulic chamber 20 of the vane chamber 12.
Collide with a.

On the other hand, after the engine starts, each advanced hydraulic chamber 19
When the hydraulic oil is filled in each of the retard hydraulic chambers 20, hydraulic oil is supplied to each of the retard hydraulic chambers 20 so as to control the intake camshaft 3 controlled to the advanced side to the most retarded side. When the hydraulic oil is discharged from each advance hydraulic chamber 19, each vane 10 is driven toward the advance hydraulic chamber 19, and the rotor 6 relatively rotates in the retard direction with respect to the housing 7. When this movement is rapid, the side surface 10 b of the vane 10 on the side of the advance hydraulic chamber 19 collides with the side wall surface 12 b of the advance hydraulic chamber 19 of each vane chamber 12.

Similarly, after the engine starts, each advanced hydraulic chamber 1
9 and each of the retard hydraulic chambers 20 are filled with hydraulic oil, and hydraulic fluid is supplied to each of the advance hydraulic chambers 19 to control the intake camshaft 3 controlled to the retard side to the most advanced side. When the hydraulic oil is supplied and discharged from each retard hydraulic chamber 20, each vane 10 is driven to the retard hydraulic chamber 20 side, and the rotor 6 relatively rotates in the advance direction with respect to the housing 7. If this movement is rapid, the side surface 10 of the vane 10 on the side of the retard hydraulic chamber 20
a collides with the side wall surface 12a of the retard hydraulic chamber 20 of each vane chamber 12.

In order to mitigate the impact at the time of the collision as described above, the present embodiment is provided with means for exhibiting a damper effect as described below. That is, the wall surfaces 12a and 1a, which are contact surfaces in each vane chamber 12 of the housing 7,
Oil reservoir holes 14a and 14b are provided in the outermost portion of 2b, respectively. On the other hand, the side faces 10a and 10b serving as contact surfaces in each vane 10 have oil sump holes
Protrusions 15a and 15b are provided to fit with a slight clearance with 4a and 14b, respectively.

In the case where the vane 10 collides with the housing 7, for example, the side surface 10 b of the vane 10 on the side of the advance hydraulic chamber 19 is
In the case of collision, as shown in FIG. 3, the convex portion 15b enters the oil reservoir hole 14b and tries to compress the oil inside. At this time, the oil escapes from the slight clearance 16 and the collision speed between the vane 10 and the housing 7 is reduced. As a result, no hitting sound is generated due to the collision.

Here, the fitting portion composed of the oil reservoir hole 14a and the projection 15a and the oil reservoir hole 14b and the projection 15b
The reason why the fitting portion constituted by the above is provided at the outermost portion of the contact surface when viewed from the rotation shaft of the rotor 6 and the housing 7 is as follows. (1) Even when the amount of oil decreases, the oil collects outside due to the centrifugal force due to the rotation of the device, and the oil accumulation holes 14a, 14
Since oil is guided to b, oil does not run out from the oil sump hole. (2) Oil sump hole 14 with respect to rotation angle of vane 10
The insertion stroke of the projections 15a, 15b into the a, 14b can be increased, and the effect of reducing the collision speed is great. (3) Conversely, since the rotation angle with respect to the stroke is reduced, adverse effects on the responsiveness of the device (that is, the relative rotation speed of the rotor 6 with respect to the housing 7) are small.

In the above embodiment, all the advance hydraulic chambers 19
Also, since six fitting portions are provided corresponding to all the retard hydraulic chambers 20, that is, corresponding to all the contact surfaces, no matter what angle the valve timing control device 1 is stopped. The oil remains in one of the oil sump holes 14a and 14b, which has a great effect particularly at the time of starting. However, a certain effect can be obtained only by forming the fitting portions on some but not all the contact surfaces.

In the above embodiment, the housing 7 is driven by the crankshaft, and the rotor 6 is connected to the intake camshaft 3. On the contrary, the housing 7 is connected to the intake camshaft 3. Alternatively, the rotor 6 may be driven by a crankshaft. In this configuration, the same effect as in the above embodiment can be obtained. Further, when the housing 7 or the rotor 6 is driven by the crankshaft, any of a chain, a belt, and a gear can be adopted as the drive transmission means.

In the above embodiment, the present invention is applied to the valve timing control device in which the hydraulic chambers 19 and 20 are formed on both sides of each vane 10.
Valve timing control in which the rotor 6 is relatively rotated in both directions with respect to the housing 7 by the balance between the hydraulic chamber and the urging means such as a compression coil spring provided on the other side. You may apply to an apparatus. Furthermore, the shape of the vane 10 and the vane chamber 12 is not limited to a fan shape.
0 may be plate-shaped.

[0035]

As described above, according to the present invention,
A first rotating body having a concave portion on the inner peripheral surface and a second rotating body having a vane defining the concave portion in two chambers having at least one of them as a hydraulic chamber are provided coaxially and supplied to the hydraulic chamber. Controlling the hydraulic pressure to rotate the first rotating body and the second rotating body relative to each other, and the camshaft linked to the other rotating body with respect to the rotation phase of the crankshaft driving one of the rotating bodies. In the vane type valve timing control device having a structure in which the rotation phases of the first and second rotating bodies are shifted, the first rotating body and the second rotating body violently collide with each other due to torque fluctuations of the camshaft when the fluid volume in the hydraulic chamber is reduced, and a tapping sound is generated. Can be prevented with a simple structure. The mitigation of the impact at the time of the collision is also effective in preventing damage to the device.

[Brief description of the drawings]

FIG. 1 is a front sectional view of a valve timing control device for an internal combustion engine according to an embodiment of the present invention.

FIG. 2 is a sectional view taken along line AA in FIG.

FIG. 3 is an enlarged sectional view of a fitting portion provided on a contact surface between a vane of a rotor and a vane chamber of a housing.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Valve timing control device 2 ... Cylinder head 2a ... Bearing part 3 ... Intake side camshaft 3a ... Flange 4 ... Timing chain 5 ... Side plate 5a ... Boss 5b ... Outer peripheral surface 6 ... Rotor (2nd rotating body) 7 ... Housing (1st rotating body) 7a ... outer peripheral surface 7b ... external teeth 8 ... cover 9 ... shaft part 10 ... vane 10a ... side surface on the clockwise side 10b ... side surface on the counterclockwise side 11 ... hole part 12 ... vane chamber 12a ... Wall surface on the clockwise side 12b Wall surface on the counterclockwise side 13 Partition wall 14a, 14b Oil reservoir hole (fitting portion) 15a, 15b Projection (fitting portion) 16 Clearance 18 Bolt 19 Lead angle Hydraulic chamber 20 ... retard hydraulic chamber 21 ... oil passage for advance 22 ... oil passage for retard 23 ... oil control valve (OCV) (directional control valve) (control means) 24 ... oil groove 25 ... oil passage 26 ... off Missing 27 ... oil passage 28 ... oil groove 29 ... oil groove 30 ... oil passage 31 ... oil hole 32 ... oil passage 33 ... oil groove 35 ... engine electronic control unit (ECU) (control means) 36 ... oil pump 37 ... oil pan

Claims (2)

[Claims] 1. A first rotating body having at least one concave portion on an inner peripheral surface and rotatably provided about a rotation axis, and the concave portion being provided in two chambers each having at least one hydraulic chamber. A second rotating body having at least one partitioning vane and rotatably provided coaxially with the rotation axis; and a crankshaft for rotating one of the first rotating body or the second rotating body. A camshaft that rotates in conjunction with the other of the first rotator and the second rotator to drive a valve; and controls an amount of liquid supplied to the hydraulic chamber according to an engine operating state. Control means for relatively rotating the first rotator and the second rotator about the rotation axis. A valve timing control device for an internal combustion engine, comprising: Make up the phase A fitting portion capable of fitting with a predetermined clearance between a contact surface of the first rotating body and a contact surface of the second rotating body that can abut against each other in a pair rotation is provided. A valve timing control device for an internal combustion engine, characterized by: 2. The valve timing control device for an internal combustion engine according to claim 1, wherein the fitting portion is provided on a portion of the contact surface that is outermost than the rotation shaft.