The present invention relates to a valve timing control apparatus which controls the timing of the opening and closing of intake and exhaust valves in an internal combustion engine.
Conventional valve timing control apparatuses include those having a rotor linked to a camshaft of an internal combustion engine; a housing member for supporting the rotor in a relatively rotational manner; a front plate member joined to one axial end of the housing member; a rear plate member joined to the other axial end of the housing member and provided with a drive portion linked to the drive shaft of the internal combustion engine; a hydraulic chamber partitioned by a vane and provided between the rotor and a housing that comprises the housing member, the front plate member, and the rear plate member; and a front cover that covers the front plate member and the housing member forming the hydraulic chamber, and is joined to the rear plate member via a seal member (for an example, see Patent Document 1).
[Patent Document 1] Japanese Laid-open Patent Application No. 2002-188414
In conventional valve timing control apparatuses such as that described above, the housing member and the front plate member are covered with a front cover in order to prevent oil supplied to the hydraulic chamber from leaking out of the internal combustion engine. Adopting this approach has been problematic in that the apparatus is made larger in the axial direction, and the number of parts increases, driving up costs. Another problem is that a larger apparatus limits the degree of freedom in mounting the apparatus in the internal combustion engine.
In view of the foregoing, a technical object of the present invention is to prevent oil from leaking out, to reduce axial dimensions, and to reduce the number of parts and the cost in a valve timing control apparatus.
Means for Solving the Problems
The technical means employed by the present invention for solving the above-mentioned problems relate to a valve timing control apparatus comprising a driven member linked to a camshaft of an internal combustion engine; a drive member which is linked to the drive shaft of the internal combustion engine and supports the driven member in a relatively rotational manner; and a hydraulic chamber which is partitioned by a vane and is disposed between the driven member and the drive member, wherein the drive member comprises an outer rotor forming the hydraulic chamber together with the driven member; a housing member including a front plate portion joined to one axial end of the outer rotor and a tubular portion linked the front plate portion and positioned on the outer radial side of the outer rotor; and a rear plate member joined to the other axial end of the outer rotor and to the housing member.
According to these technical means, the periphery of the hydraulic chamber can be enclosed by the tubular portion and the front plate portion of the housing member. Therefore, oil in the hydraulic chamber can be prevented from leaking through the housing member to the outside. Furthermore, the housing member can double as a covering member for covering the periphery of the drive member, allowing the drive member to be made more compact in the axial direction, and the number of parts and the cost to be reduced. The outer rotor and the housing member can be separate members, whereby the outer rotor and the housing member can be formed from different materials.
According to a further technical means used to solve the above-mentioned problems, the housing member, the outer rotor, and the rear plate member are integrally fixed together by a fastening member, a head portion of the fastening member is interlocked with the rear plate member, a shaft portion thereof is passed through a hole in the outer rotor, and the sealant-coated male threaded portion is threadably engaged with a female threaded portion of the housing member.
According to these technical means, the sealant-coated male threaded portion of the fastening member is threadably engaged with the female threaded portion of the housing member, preventing the oil in the hydraulic chamber from leaking to the outside from between the fastening member and the housing member. Therefore, oil leakage can be prevented using a simple configuration.
According to a further technical means used to solve the above-mentioned problems, the hole has a stepped tubular shape, with a large-diameter portion on the side of the front plate portion and a small-diameter portion on the side of the rear plate member.
According to these technical means, excess sealant squeezed out by the threadable engagement of the fastening member and the housing member flows into the large-diameter portion of the hole to form a seal, and can therefore be prevented from flowing toward the hydraulic chamber.
According to a further technical means used to solve the above-mentioned problems, a through hole for passing the fastening member is formed in the rear plate member, and a seal member is provided for sealing the through hole.
According to these technical means, the oil in the hydraulic chamber can be prevented from leaking out from between the fastening member and the rear plate member. Therefore, oil leakage can be prevented using a simple configuration.
According to a further technical means used to solve the above-mentioned problems, the through hole has a larger diameter than the small-diameter portion of the hole; at least a portion of the head portion of the fastening member is inserted into the through hole; and the seal member is placed within the through hole and is sandwiched between the head portion of the fastening member and the other axial end of the outer rotor.
According to these technical means, the seal between the fastening member and the rear plate member can be adequately ensured using a simple structure in which the seal member is merely sandwiched between the head portion of the fastening member and the other axial end of the outer rotor.
A further technical means used to solve the above-mentioned problems has a seal member disposed on the joint surface of the housing member and the rear plate member.
According to these technical means, the oil in the hydraulic chamber can be prevented from leaking out from between the housing member and the rear plate member.
According to a further technical means used to solve the above-mentioned problems, the outer rotor is composed of an iron-based metal, and the housing member is composed of a light metal.
According to these technical means, the housing member and the entire apparatus can be made more lightweight while the strength of the outer rotor is ensured.
According to the present invention, the oil in the hydraulic chamber can be prevented from leaking to the outside of the housing member. Furthermore, the drive member can be made more compact in the axial direction, and the number of parts and the cost can be reduced.
An embodiment of a valve timing control apparatus 1 according to the present invention will be described below with reference to the accompanying drawings.
As shown in
The camshaft 1 has a cam (not shown) for opening and closing the intake or exhaust valves (not shown) of the internal combustion engine. The camshaft 1 is rotatably supported by a cylinder head 5 of the internal combustion engine.
The rotor 2 is integrally fixed by a bolt 23 to the axially forward end (left side in
The drive member 30 has the outer rotor 31 forming the hydraulic chamber 35 together with the rotor 2, a substantially bottomed tubular housing member 3 for housing the outer rotor 31 in the internal peripheral part thereof, and a rear plate member 4 joined to the end face 3a on the side of the opening in the housing member 3. A seal member 38 is disposed on the joint surface of the housing member 3 and the rear plate member 4. The seal member 38 seals the joint surface of the housing member 3 and the rear plate member 4, and is provided to prevent leakage of oil from the hydraulic chamber 35 to the outside.
As shown in
The outer rotor 31 and the housing member 3 are separate members integrally fixed together by the bolt 36, allowing for the outer rotor 31 and the housing member 3 to be formed from different materials. In this case, the outer rotor 31 is preferably composed of an iron-based metal, and the housing member 3 is preferably composed of aluminum or another light metal. The required strength can thereby be obtained for the outer rotor 2, and the housing member 3 and the entire apparatus can be made more lightweight.
The radially inwardly extending protrusions 31a are formed spaced around the periphery of the outer rotor 31. The hydraulic chamber 35 is formed in the space between adjoining protrusions 31a. The rotor 2 is rotationally engaged with the internal peripheral surface 31d of the protrusions 31a. The vanes 6, which partition the hydraulic chamber 35 into spark-advance and spark-retard chambers in a liquid-tight manner as mentioned above, are in frictional contact with the internal peripheral surface 31b of the outer rotor.
The housing member 3 is a substantially bottomed tubular member having a front plate portion 32 that is joined to one axial end (left side in
The front plate portion 32 comprises a tubular portion 32c that has a hole 32b for fastening the bolt 23, and a discoid portion 32d for hermetically closing the front side of the hydraulic chamber 35. The hole 32b provided in the central part of the front plate portion 32 is blocked in a liquid-tight manner by fixing a cap 37 with the aid of a seal washer 37a. The front plate portion 32 is positioned in contact with the axial front-end surface (an end side) 31g of the outer rotor 31. The front plate portion 32 blocks the front end face (left side in
A torsion spring 7 is positioned between a depression 32e formed on the internal periphery of the tubular portion 32c of the front plate portion 32, and a circular groove 31k formed on the front-end surface (an end side) 31g in the axial direction of the rotor 2. The torsion spring 7 is attached to the front plate portion 32 on one end and to the rotor 2 on the other end. The torsion spring 7 thereby urges the rotor 2 to advance straight forward in relation to the drive member 30.
The housing member 3 and the rear plate member 4 are integrally fixed together by the bolt 36. The bolt 36 passes through the hole 31c of the outer rotor 31, and the male threaded portion 36a coated with sealant A threadably engages the female threaded portion 32a formed on the front plate portion 32. The hole 31c is formed as a stepped cylinder in which the level changes in the axially directed intermediate portion of the hole, as shown in
A seal member 39 is disposed between the head portion 36b of the bolt 36 and the rear plate member 4, as shown in
The rear plate member 4 has a larger diameter than the housing member 3, is joined to the axial back-end surface 31h of the outer rotor 31, and blocks the rear side (the right side in
Following is a description of the operation of a valve timing control apparatus configured as described above.
While oil is fed through supply lines connected to the spark-advance and spark-retard chambers of the hydraulic chamber 35, a torque transmitted from the crankshaft of the internal combustion engine to the pulley 4a is further transmitted from the drive member 30 to the rotor 2 via the oil thus fed, whereby the pulley 4a and the camshaft 1 are made to rotate integrally together. As a result, the camshaft 1 of the internal combustion engine is caused to rotate in sync with the crankshaft of the internal combustion engine. In this case, the outer rotor 31, which forms the hydraulic chamber 35, is covered by the housing member 3, which has the front plate portion 32 and the tubular portion 33 linked thereto. Furthermore, the housing member 3 is joined and fixed to the rear plate member 4 via the seal member 38. Therefore, the oil fed to the hydraulic chamber 35 is prevented from leaking to the outside.
The rate at which the oil is fed in this state is adjusted, and the oil pressure generated in the spark-advance and spark-retard chambers of the hydraulic chamber 35 is also adjusted, whereupon the rotor 2 is caused to rotate relative to the drive member 30, and the position of the camshaft 1 relative to the pulley 4a is varied. The rotation timing of the camshaft 1 of the internal combustion engine relative to the drives shaft is thus adjusted.
1 Camshaft
2 Rotor (driven member)
3 Housing member
4 Rear plate member
4
c Through hole
6 Vane
30 Drive member
31 Outer rotor
31
c Hole
31
j Large-diameter portion
31
m Small-diameter portion
32 Front plate portion
32
a Female threaded portion
33 Tubular portion
35 Hydraulic chamber
36 Bolt (fastening member)
36
a Male threaded portion
36
b Head portion
36
c Shaft portion
38 Seal member on joint surface of housing member and rear plate member
39 Seal member for seal member
A Sealant
Number | Date | Country | Kind |
---|---|---|---|
2004-183845 | Jun 2004 | JP | national |
Filing Document | Filing Date | Country | Kind | 371c Date |
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PCT/JP05/11317 | 6/21/2005 | WO | 12/19/2006 |