JPH01134012A - Valve system for internal-combustion engine - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

Detailed Description of the Invention A0 Objective of the Invention (1) Industrial Application Field The present invention relates to a cylindrical rotating shaft connected to a camshaft; a timing wheel driven from a crankshaft; a cylindrical housing that is rotatably supported by a rotating shaft around the same axis while being prevented from moving and is provided with the timing wheel; disposed coaxially with the rotating shaft and the housing with one axial end facing the hydraulic chamber; A piston that is axially biased by a spring; and a phase adjustment that interlocks and connects the piston, housing, and rotary shaft to change the rotational phase of the timing wheel and rotary shaft in accordance with the axial movement of the piston. The present invention relates to a valve train for an internal combustion engine, which includes a mechanism and;

(2) Prior art Conventionally, such a device has been used, for example, in Japanese Patent Application Laid-Open No. 61-26881.
It is known from Publication No. 0.

(3) Problems to be Solved by the Invention This device changes the operating timing of the engine's intake valve or exhaust valve by changing the phase between the timing wheel and the camshaft using a phase adjustment mechanism. In the above conventional system, the piston moves between two positions: when hydraulic pressure is supplied to the hydraulic chamber and when hydraulic pressure is released, and the opening/closing timing of the intake valve or exhaust valve is controlled by a fixed value. You can only control whether to speed it up or slow it down by a certain value. Moreover, in the above-mentioned conventional device, both ends of the housing, which is equipped with a pulley as a timing wheel, are supported by a rotating shaft, so the pressure-receiving area of the piston must be made small, which limits the operating speed of the piston. Ta.

The present invention has been made in view of the above circumstances, and it is an object of the present invention to provide a valve operating system for an internal combustion engine that allows stepless control of opening/closing timing and has a quick operating speed.

B0 Structure of the Invention (1) Means for Solving the Problems According to the present invention, there is a hydraulic chamber interlocked with and connected to the piston between the hydraulic chamber facing one axial end of the piston and the hydraulic pressure supply path and the hydraulic release path. A servo valve is interposed, which includes a sleeve that is slidably fitted into the rotating shaft and a spool that is movable relative to the shaft and slidably fitted to the sleeve. , the communication state between the hydraulic chamber and the hydraulic pressure supply path or the hydraulic pressure release path is switched by the axial movement of the spool to the disconnected state by the axial movement of the piston and sleeve following the axial movement of the spool, and the housing is rotated. A bearing for supporting the shaft and a phase adjustment mechanism are arranged near the position where the timing wheel is provided in the housing.

(2) Effect According to the above configuration, when the spool is driven in the axial direction according to the operating state of the engine and the hydraulic chamber is communicated with the hydraulic pressure supply path or the hydraulic pressure release path, the hydraulic pressure is supplied to the hydraulic chamber or the hydraulic pressure is As the piston moves in the axial direction in response to the release, the sleeve also moves in the axial direction, thereby switching the communication state of the hydraulic pressure supply path to the hydraulic chamber or the hydraulic pressure release path to the disconnected state, so that the piston is moved along the axis of the spool. The spool is moved in the axial direction by an amount corresponding to the amount of directional movement, and the phase between the timing wheel and the camshaft can be controlled steplessly in accordance with the amount of axial movement of the spool. In addition, the housing is supported by a rotating shaft via a bearing near the position where the timing wheel is provided, and the phase adjustment mechanism is placed near the timing wheel, reducing the load on the tip of the housing and allowing rotation. This enables a cantilever support structure for the housing by the shaft, thereby increasing the pressure-receiving area of the piston and increasing the operating speed.

(3) Embodiment Hereinafter, embodiments of the present invention will be explained with reference to the drawings. First, in FIG. is rotatably supported by the engine body 2, and includes a pulley 4 as a timing wheel around which a timing belt 3 for transmitting rotational power from the engine crankshaft (not shown) is wound, and the camshaft. 1 is interlocked and connected via a timing change means 5 that makes it possible to shift the phases of the pulley 4 and the camshaft 1.

The timing change means 5 includes a rotating shaft 6 coaxially connected to the camshaft 1, a cylindrical housing 7 that is integrally provided with the pulley 4 and coaxially surrounds the rotating shaft 6, and a hydraulic chamber 18 at one end in the axial direction. A piston 8 is disposed coaxially with the housing 7 and the rotating shaft 6 while being biased in the axial direction by a spring 32, a servo valve 9 regulating the amount of movement of the piston 8, and an axis of the piston 8. It includes a phase adjustment mechanism 10 that interlocks and connects the piston 8, the housing 7, and the rotary shaft 6 to change the rotational phase of the pulley 4 and the rotary shaft 6 in response to directional movement.

The rotating shaft 6 is formed into a cylindrical shape with a bottom, integrally having a shaft portion 6a at its closed end, and a bolt 1 passing through the closed end.
1 to the camshaft 1, the shaft portion 6a is coaxially connected to the end of the camshaft 1. Further, a pulley 4 is integrally provided on the outer periphery of the housing 7 near the open end, that is, near the camshaft 1. An end plate 12 in the form of an original plate is fixed to the end of the housing 7 on the camshaft 1 side, and this end plate 12 covers the closed end exception edge of the rotating shaft 6.
A sealing member 13 is interposed between the inner periphery of the rotating shaft 6 and the outer periphery of the shaft portion 6a of the rotating shaft 6. Further, a bearing 14 is interposed between the inner surface of the housing 7 and the outer surface of the rotating shaft 6 near the position where the pulley 4 is disposed. This bearing 14 is disposed between the housing 7 and the rotating shaft 6 such that one end of its outer ring engages with the housing 7 and the other end of its inner ring is held on the rotating shaft 6. The pulley 4 is prevented from moving relative to the rotating shaft 6, that is, the camshaft 1 in the axial direction, but is allowed to rotate relative to the axis.

At the end of the housing 7 opposite to the camshaft 1,
A closing plate 7a having a through hole 15 is fixed to its center, and the piston 8 has a cylindrical portion 8a that slides on the inner surface of the through hole 15 and a ring portion 8b that slides on the inner surface of the housing 7. A sealing member 16 is fitted onto the outer surface of the cylindrical portion 8a to slide on the inner surface of the through hole 15, and a sealing member 17 that slides onto the inner surface of the housing 7 is fitted on the outer surface of the ring portion 8b. is fitted. As a result, a hydraulic chamber 18 is defined between the housing 7, the closing plate 7a, and the piston 8 between both seal members 16 and 17, and when hydraulic pressure is supplied to the hydraulic chamber 18, the piston 8 moves along the axial direction. It is pressed toward the camshaft 1 side. In addition, both seal members 16 and 17 are of a piston ring type that has a cut in a part in the circumferential direction, and by using such a type of seal member 16 and 17, it is possible to reduce the sliding resistance of the piston 8. It is.

The piston 8 is integrally provided with a support cylindrical portion 8d extending from the ring portion 8b toward the camshaft 1 to be inserted between the housing 7 and the rotating shaft 6, and the support cylindrical portion 8d and the housing 7 and the rotating shaft 6 are interlocked and connected via a phase adjustment mechanism 10.

In FIGS. 2(a) and 2(b), the phase adjustment mechanism 10
A guide groove 19 provided on the outer surface of the rotating shaft 6, and a guide hole 20 provided in the housing 7 corresponding to the guide groove 19.
A roller pin 21 is pivotally supported on the support tube 8d to fit into the guide groove 19, and a roller pin 22 is coaxial with the roller bin 21 and pivotally supported on the support tube 8d so as to fit into the guide hole 20. Become. Moreover, the guide groove 19 and the guide hole 2
o are formed to be inclined with respect to the axes of the rotating shaft 6 and the housing 7 and intersect with each other, and the piston 8
At the same time, as the roller pins 21 and 22 move in the axial direction of the rotating shaft 6 and the housing 7, the roller pins 21 and 22 are transferred within the guide groove 19 and the guide hole 20, and the rotating shaft 6 and the housing 7 are moved. Rotate in opposite directions. As a result, the phases of the rotating shaft 6 and camshaft 1 and the housing 7 and pulley 4 change. That is, when the piston 8 moves to the position closest to the camshaft 1, the relative positions of the rotating shaft 6 and the housing 7 in the circumferential direction become as shown in FIG. When moved to this position, the relative positions of the rotating shaft 6 and the housing 7 in the circumferential direction become as shown in FIG. 2 (b). Moreover, the phase adjustment mechanism lO is arranged at a plurality of locations, for example, at three locations equally spaced in the circumferential direction of the piston 8, corresponding to the portion where the pulley 4 is provided.
It is placed at a specific location.

Referring again to FIG. 1, a cylindrical cover 23 is fitted onto the outer periphery of the housing 7 to prevent the roller bin 22 from falling out of the guide hole 20, and this cover 23 is fixed to the housing 7. Moreover, seal members 25.2 are provided between the housing 7 and the cover 23 on both sides of the guide hole 20.
6 is interposed.

Further, the rotating shaft 6 is provided with a breath hole 35 through which the rotating shaft 6 and the housing 7 communicate with each other.

The servo valve 9 includes a cylindrical sleeve 29 that is slidably fitted onto the rotating shaft 6, and a cylindrical spool 3o that is slidably fitted into the sleeve 29. Further, a spring 32 is compressed between the sleeve 29 and the closed end of the rotating shaft 6, and the spring force of the spring 32 causes the sleeve 29 to be pushed in a direction such that one end thereof comes into contact with the connecting plate portion 8c of the piston 8. Therefore, the piston 8 is also urged in a direction to contract the hydraulic chamber 18 against the hydraulic pressure of the hydraulic chamber 18 .

The engine body 2 is provided with a first hydraulic pressure supply passage 37 connected to the hydraulic pump 36 , and the camshaft 1 is provided with an annular groove 38 on its outer surface that communicates with the first hydraulic supply passage 37 . A second hydraulic supply path 39 is drilled that leads to.

Further, the rotating shaft 6 is provided with a third hydraulic pressure supply path 40 that is always in communication with the second hydraulic pressure supply path 39, and the inner surface of the rotating shaft 6 has a third
An annular groove 41 communicating with the hydraulic pressure supply path 40 is provided. A pair of annular seal members 42 and 43 are interposed between the camshaft 1 and the engine body 2 so as to sandwich the annular groove 38 of the camshaft 1 therebetween.
An annular seal member 44 for maintaining communication between the second and third hydraulic supply passages 39 and 40 is interposed therebetween.

The sleeve 29 is provided with an oil hole 45 that is always in communication with the annular groove 41 regardless of its axial position with respect to the rotating shaft 6, and an oil hole 45 is provided at a position adjacent to the inner open end of the oil hole 45 on the camshaft 1 side. An annular groove 46 is bored in the inner surface of the tube. Further, an oil passage 4'7 is formed in the sleeve 29 and the connecting plate portion 8c in contact with the sleeve 29, which communicates the annular groove 46 with the hydraulic chamber 18. Further, the bolt II and the camshaft 1 have a hydraulic release path 49 leading to the oil tank 48.
is drilled.

An annular groove 50 is bored on the outer surface of the spool 30,
The width of the annular groove 50 along the axial direction of the spool 30 is equal to the width of the oil hole 4
5 and the annular groove 46 are set to such an extent that the annular groove 50 can communicate with each other. This spool 30 has two positions: a blocking position where only the oil hole 45 is communicated with the annular groove 50, a supply position where the oil hole 45 and the annular groove 46 are communicated via the annular groove 50, and a supply position where the annular groove 46 is connected to the hydraulic release path 49. It is movable between three axial relative positions with a release position for communicating. Also sleeve 2
A stopper 51 projecting radially inward is integrally provided at the end of the camshaft 9 of 9 on the camshaft 1 side.
1 restricts the relative movement of the spools in the axial direction.

Further, an operating shaft 31 is inserted into the four hydraulic pressure release passages so as to be movable in the axial direction, and the tip of this operating shaft 31 is connected to the spool 30. Also, the closing plate 7a of the housing 7
A cap 27 is fixed to the cap 27 to close the through hole 15, and a spring 28 is interposed between the camp 27 and the spool 30 to bias the spool 30 toward the camshaft 1.

Next, to explain the operation of this embodiment, the rotational power transmitted from the crankshaft of the engine via the timing belt 3 is transmitted from the pulley 4 via the timing change means 5 to the camshaft 1. The intake valve or the exhaust valve is driven to open or close according to the rotation of the valve.

In order to change the opening/closing timing of the intake valve or the exhaust valve, the operating shaft 31 is moved to a desired position. For example, in FIG. 1, the operating shaft 31 is moved to the right as much as possible, the relative axial positions of the sleeve 29 and the spool 30 are at the blocking position where only the annular groove 50 communicates with the oil hole 45, and the phase adjustment mechanism 10 is in the state shown in FIG. 2(a).

Therefore, when the operating shaft 31 is moved to the left and the spool 30 is moved in the axial direction (toward the left side in FIG. 1), the annular groove 46
is the release position communicating with the hydraulic release path 49.

Therefore, the hydraulic pressure in the hydraulic chamber 18 is released, the sleeve 29 and the piston 8 are moved in one direction in the axial direction by the spring force of the spring 32, and the rotating shaft 6 and the housing 7 are rotated relative to each other by the phase adjustment mechanism 10. The opening/closing timing of the exhaust valve changes. Furthermore, as the sleeve 29 moves in one axial direction, the spool 30 moves relative to the sleeve 29 in the other axial direction, and the relative axial positions of the spool 30 and the sleeve 29 become the blocking position.

Therefore, the amount of movement of the piston 8 is determined according to the amount of axial movement of the spool 30, and the amount of advance or delay of the opening/closing timing is determined accordingly. control becomes possible.

During such operation, since the seal members 16 and 17 fitted to the piston 8 are made of piston ring quibs, the sliding resistance is low, and therefore the operation of the piston 8, that is, the adjustment operation of the phase adjustment mechanism 10, is quickly performed. can do.

Furthermore, when the servo valve 9 is in the cutoff position, if the operation shaft 31 is moved to the other side in the axial direction and the spool 30 is relatively operated from the cutoff position to the other side in the axial direction, the oil hole 45 and The annular groove 46 is in the supply position where it is communicated, and the hydraulic pressure from the hydraulic pump 36 is supplied to the hydraulic chamber 18, so that the piston 8 is pushed and driven toward the other side in the axial direction against the spring force of the spring 32. As the piston 8 moves to the other side in the axial direction, the rotating shaft 6 and the housing 7 are rotated relative to each other by the action of the phase adjustment mechanism 10, and the opening/closing timing of the intake valve or the exhaust valve is changed. Furthermore, since the sleeve 29 also moves in accordance with the axial movement of the piston 8, the relative axial positions of the spool 30 and the sleeve 29 are at the blocking position. Therefore, the amount of movement of the piston 8 is determined according to the amount of movement of the spool 30, and the opening/closing timing is controlled steplessly. Moreover, the back pressure between the piston 8 and the rotation shaft 6 is quickly released by the breeze hole 35 provided in the rotation shaft 6, so that the piston 8 can be operated more quickly.

In this timing changing means 5, the housing 7 provided with the pulley 4 is supported by the rotating shaft 6 via a bearing 14 near the position where the pulley 4 is provided, and the phase adjustment mechanism 10 is also mounted on the pulley 4. Since they are disposed at corresponding portions, the load applied to the distal end side of the housing 7 is reduced, and it becomes unnecessary to support the distal end side of the housing 7 with the rotating shaft 6, making it possible to provide a cantilever support structure. Therefore, there is no need to provide a portion of the rotating shaft 6 that penetrates the connecting plate portion 8C of the piston 8 and supports the tip of the housing 7, and the pressure receiving area of the piston 8 facing the hydraulic chamber 18 can be made relatively large. Thereby, the operation of the piston 8, that is, the operation of the phase adjustment mechanism 10 can be made quick.

FIG. 3 shows another embodiment of the present invention, and parts corresponding to the embodiments described above are given the same reference numerals.

The phase adjustment mechanism 10' includes a housing 7 and a piston 8.
and a helical spline 53 that connects the piston 8 and the rotating shaft 6. This phase adjustment mechanism 10' also allows the housing 7 and the The phase of the rotating shaft 6 can be shifted.

As still another embodiment of the present invention, one of the rotating shaft 6 and the piston 8 and the piston 8 and the housing 7 are connected in a structure that prevents relative rotation, and the other is connected in a structure that prevents relative rotation. The phase adjustment mechanism may be configured to be connected in a relatively rotating structure.

C6 Effects of the Invention As described above, according to the present invention, there is a gap between the hydraulic chamber facing one axial end of the piston, the hydraulic pressure supply path, and the hydraulic pressure release path, which is interlocked and connected to the piston and is located within the rotating shaft. A servo valve is interposed, which includes a sleeve that is slidably fitted and a spool that is slidably fitted to the sleeve and capable of relative axial movement. A bearing configured to switch the communication state between the hydraulic chamber and the hydraulic pressure supply path or the hydraulic pressure release path to a disconnected state by axial movement of the piston and sleeve following the axial movement of the spool, and for supporting the housing on the rotating shaft. Since the phase adjustment mechanism is disposed near the position where the timing shaft is provided in the housing, the piston is moved by an amount corresponding to the amount of movement of the spool, and the relative rotation amount between the timing shaft and the camshaft is This makes it possible to steplessly adjust the opening and closing timing of the intake valve or exhaust valve, and also reduces the load on the front end of the housing, making it possible to support the housing on a cantilevered structure. This makes it possible to increase the pressure receiving area of the piston and increase the operating speed.

[Brief explanation of the drawing]

1 and 2 show an embodiment of the present invention,
FIG. 1 is a longitudinal cross-sectional view, FIG. 2 is an enlarged cross-sectional view taken along the line ■--■ in FIG. 1, and FIG. 3 is a vertical cross-sectional view of another embodiment of the present invention. 1...Camshaft, 4...Pulley as timing axis,
6... Rotating shaft, 7... Housing, 8... Piston, 9... Servo valve, 10.10'... Phase adjustment mechanism, 14... Bearing, 18... Hydraulic chamber, 29...
Sleeve, 30... Spool, 37, 39.40...
・Hydraulic pressure supply path, 49...Hydraulic pressure release path

Claims (1)

[Claims] a cylindrical rotating shaft connected to a camshaft; a timing wheel driven from a crankshaft; a timing wheel rotatably supported by the rotating shaft around the same axis while being prevented from relative axial movement; a cylindrical housing provided; a piston disposed coaxially with the rotating shaft and the housing with one axial end facing the hydraulic chamber; and a spring biased toward one side in the axial direction; A piston is used to change the rotational phase of the timing wheel and rotating shaft.
In a valve operating system for an internal combustion engine comprising a phase adjustment mechanism that interlocks and connects a housing and a rotating shaft, a hydraulic chamber facing one axial end of the piston and a hydraulic pressure supply path and a hydraulic pressure release path are provided with a A servo valve is interposed, which is composed of a sleeve that is interlocked and connected and is slidably fitted into the rotating shaft, and a spool that is movable relative to the axis and slidably fitted to the sleeve. The servo valve is configured to switch the state of communication between the hydraulic chamber and the hydraulic pressure supply path or the hydraulic pressure release path by the axial movement of the spool to the disconnected state by the axial movement of the piston and sleeve following the axial movement of the spool, A valve train for an internal combustion engine, wherein a bearing for supporting a housing on a rotating shaft and a phase adjustment mechanism are disposed near a position where a timing wheel is provided on the housing.