JPH0353448B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION A. Object of the Invention (1) Industrial Application Field The present invention provides a cylindrical rotating shaft connected to a camshaft; a timing wheel driven from a crankshaft;
a cylindrical housing rotatably supported by a rotary shaft around the same axis while being prevented from relative axial movement, and provided with the timing wheel; one end in the axial direction facing the hydraulic chamber; A piston that is arranged coaxially and is biased by a spring to one side in the axial direction; the piston, housing, and rotating shaft are interlocked and connected to change the rotational phase of the timing wheel and rotating shaft according to the axial movement of the piston. The present invention relates to a valve operating system for an internal combustion engine, including a phase adjustment mechanism;

(2) Conventional technology Conventionally, such a device is disclosed in, for example, Japanese Patent Application Laid-Open No.
It is known from the publication No. 268810.

(3) Problems to be Solved by the Invention This device changes the operating timing of the intake valve or exhaust valve of the engine by changing the phase between the timing wheel and the camshaft using a phase adjustment mechanism. In the conventional type described above, 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 advanced by a certain value. The only control available is to slow down the speed by a certain value or to slow it down by a certain value. Moreover, in the above-mentioned conventional type, since both ends of the housing, which is equipped with a pulley as a timing wheel, are supported by a rotating shaft, 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.

B. Structure of the Invention (1) Means for Solving Problems According to the present invention, there is a hydraulic chamber that is interlocked with or connected to the piston, and the hydraulic pressure supply path and the hydraulic pressure release path are connected to the hydraulic chamber facing one axial end of the piston. 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 interlocking 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 that follow 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 linked to the hydraulic pressure supply path or the hydraulic pressure release path, the hydraulic pressure is not supplied to the hydraulic chamber or the hydraulic pressure is When 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, and therefore the piston moves to the spool. It will move in the axial direction by an amount corresponding to the amount of axial movement of
The phase of the timing wheel and the camshaft can be controlled steplessly according to 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) Embodiments Below, embodiments of the present invention will be explained with reference to the drawings. First, in FIG. 1 showing an embodiment of the present invention, a camshaft 1 for opening and closing an intake valve or an exhaust valve (not shown) is connected to the engine body. The camshaft 1 is rotatably supported by a pulley 4 as a timing wheel around which a timing belt 3 for transmitting rotational power from an engine crankshaft (not shown) is wound. The pulley 4 and the camshaft 1 are interlocked and connected via a timing change means 5 that allows the phases of the camshaft 1 to be shifted.

The timing change means 5 includes a rotating shaft 6 coaxially connected to the camshaft 1, a cylindrical housing 7 provided integrally with the pulley 4 and coaxially surrounding the rotating shaft 6, and one end in the axial direction connected to a hydraulic chamber 18. A piston 8 is disposed coaxially with the housing 7 and the rotating shaft 6 while being biased toward one side in the axial direction by a spring 32, a servo valve 9 that regulates the amount of movement of the piston 8, and a servo valve 9 that regulates the amount of movement of the piston 8 in the axial direction. 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 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 by screwing a bolt 11 passing through the closed end to the camshaft 1, the shaft portion 6a is connected to the camshaft shaft. Coaxially connected to the end of 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 annular plate-shaped end plate 12 that covers the outer edge of the closed end side of the rotating shaft 6 is fixed to the end of the housing 7 on the camshaft 1 side. A seal member 13 is interposed between the outer periphery of the portion 6a and the outer periphery of the portion 6a. 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 has one end of its outer ring engaged with the housing 7, and the other end of the inner ring engaged with the rotating shaft 6.
It is disposed between the housing 7 and the rotating shaft 6 so as to engage with the housing 7.
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, there is a closing plate 7 having a through hole 15 in the center thereof.
A is fixed to the piston 8, and the piston 8 has a cylindrical portion 8a that slides in contact with the inner surface of the through hole 15, and a ring portion 8b that slides in contact with the inner surface of the housing 7.
A seal member 16 that slides on the inner surface of the through hole 15 is fitted on the outer surface of the cylindrical portion 8a, and a seal member 17 that slides on the inner surface of the housing 7 is fitted on the outer surface of the ring portion 8b. be done. As a result, a hydraulic chamber 18 is defined between the housing 7 and the closing plate 7a, and the piston 8 between both the 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. Moreover, both seal members 16,1
7 is of a piston ring type having a cut in a part in the circumferential direction, and by using such type of seal members 16 and 17, it is possible to reduce the sliding resistance of the piston 8.

The piston 8 includes a housing 7 and a rotating shaft 6.
A support cylinder part 8d extending from the ring part 8b toward the camshaft 1 side is integrally provided to be inserted between the housing 7 and the rotating shaft 6. Interlocked and connected through.

In FIGS. 2a and 2b, the phase adjustment mechanism 10
is a guide groove 19 provided on the outer surface of the rotating shaft 6;
A guide hole 20 provided in the housing 7 corresponding to the guide groove 19, a roller pin 21 pivotally supported by the support cylinder portion 8d to fit into the guide groove 19, and a guide hole 2
The roller pin 22 is coaxial with the roller pin 21 and pivotally supported by the support cylinder portion 8d so as to fit into the roller pin 21. Moreover, the guide groove 19 and the guide hole 20 are formed so as to be inclined with respect to the axes of the rotating shaft 6 and the housing 7 and intersect with each other. As the roller pins 21 and 22 move in the axial direction, the roller pins 21 and 22 move in the guide groove 19.
The rotating shaft 6 and the housing 7 rotate in opposite directions by rolling in the guide hole 20. 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. , the relative positions of the rotating shaft 6 and the housing 7 in the circumferential direction are as shown in FIG. 2b. Moreover, such phase adjustment mechanisms 10 are arranged at a plurality of locations, for example, three locations, which are equally spaced apart in the circumferential direction of the piston 8, corresponding to the portions where the pulleys 4 are provided.

Referring again to FIG. 1, a cylindrical cover 23 is fitted around the outer periphery of the housing 7 to prevent the roller pin 22 from falling out of the guide hole 20, and this cover 23 is fixed to the housing 7. Furthermore, seal members 25 and 26 are interposed between the housing 7 and the cover 23 on both sides of the guide hole 20. The inside of the rotating shaft 6 is
and a breath hole 35 communicating between the housing 7
is drilled.

The servo valve 9 includes a cylindrical sleeve 29 that is slidably fitted onto the rotating shaft 6, and a cylindrical spool 30 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.
2, the sleeve 29 is urged in a direction in which one end of the sleeve 29 comes into contact with the connecting plate portion 8c of the piston 8, so that the piston 8 also contracts in the direction of the hydraulic chamber 18 against the hydraulic pressure of the hydraulic chamber 18. is energized by

The engine body 2 includes a first pump connected to the hydraulic pump 36.
A hydraulic pressure supply path 37 is formed in the camshaft 1, and an annular groove 38 communicating with the first hydraulic pressure supply path 37 is formed in the outer surface of the camshaft 1, and a second hydraulic pressure supply path 39 communicating with the annular groove 38 is formed in the camshaft 1. Further, the rotating shaft 6 is provided with a third hydraulic pressure supply path 40 which is always in communication with the second hydraulic pressure supply path 39, and the inner surface of the rotating shaft 6 is provided with an annular groove 41 which communicates with the third hydraulic pressure supply path 40. A pair of annular seal members 42 and 43 are interposed between the camshaft 1 and the engine body 2 with the annular groove 38 of the camshaft 1 interposed therebetween, and second and third hydraulic pressure supply paths are provided between the camshaft 1 and the rotating shaft 6. An annular seal member 44 is interposed to maintain the communication state between 39 and 40.

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. An annular groove 46 is bored on the inner surface. Further, in the sleeve 29 and the connecting plate portion 8c in contact with the sleeve 29, an oil passage 47 is provided which communicates the annular groove 46 with the hydraulic chamber 18.
is drilled. Furthermore, the bolt 11 and the camshaft 1 are provided with a hydraulic release path 4 leading to the oil tank 48.
9 is drilled.

An annular groove 50 is bored on the outer surface of the spool 30, and the annular groove 50 extends along the axial direction of the spool 30.
The width of the annular groove 5 is between the oil hole 45 and the annular groove 46.
It is set to the extent that communication is possible with 0. This spool 30 has a blocking position where only the oil hole 45 communicates with the annular groove 50, a supply position where the oil hole 45 and the annular groove 46 communicate with each other via the annular groove 50, and a supply position where the oil hole 45 and the annular groove 46 communicate with each other via the annular groove 50.
It is movable between three axial relative positions with respect to a release position that communicates the hydraulic pressure release path 49 with the hydraulic pressure release path 49. Further, a stopper 51 projecting radially inward is integrally provided at the end of the sleeve 29 on the camshaft 1 side, and this stopper 51 comes into contact with the spool 30 to restrict relative movement in the axial direction.

In addition, an operating shaft 31 is inserted into the hydraulic release path 49 so as to be movable in the axial direction.
The tip of 1 is connected to a spool 30. Further, a cap 27 for closing the through hole 15 is fixed to the closing plate 7a of the housing 7.
A spring 28 is interposed between the spool 30 and the spool 30 to urge the spool 30 toward the camshaft 1 side.

Next, the operation of this embodiment will be explained. Rotational power transmitted from the engine crankshaft via the timing belt 3 is transmitted from the pulley 4 to the camshaft 1 via the timing change means 5.
In response to the rotation of the camshaft 1, an intake valve or an exhaust valve is driven to open or close.

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, and 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. 2a. Therefore, when the operating shaft 31 is moved to the left and the spool 30 is moved to one side in the axial direction (the left side in FIG. 1), the annular groove 4
6 is a 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 rotation shaft 6 and the housing 7 are rotated relative to each other by the phase adjustment mechanism 10, and the intake valve Or the opening/closing timing of the exhaust valve changes. Moreover, in response to the movement of the sleeve 29 in one direction in the axial direction,
The spool 30 moves relative to the other side in the axial direction with respect to the sleeve 29, and the relative positions of the spool 30 and the sleeve 29 in the axial direction become the blocking position. Therefore, the amount of movement of the piston 8 is determined according to the amount of movement of the spool 30 in the axial direction, and the amount of advance or delay of the opening/closing timing is determined accordingly. Stepless control is possible.

During such operation, since the seal members 16 and 17 fitted to the piston 8 are of the piston ring type, 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. It can be done.

Further, when the servo valve 9 is in the cutoff position, the operating shaft 31 is moved to the other side in the axial direction, and the spool 3 is moved to the other side in the axial direction.
0 is relatively operated from the blocking position to the other side in the axial direction, the oil hole 45 and the annular groove 4 are opened via the annular groove 50.
6 is in a connected supply position, and the hydraulic pump 36
Since the hydraulic pressure is supplied to the hydraulic chamber 18, the piston 8 is pushed against the spring force of the spring 32 toward the other side in the axial direction. As the piston 8 moves to the other side in the axial direction, the rotating shaft 6 and the housing 7 rotate relative to each other due to the action of the phase adjustment mechanism 10, and the opening/closing timing of the intake valve or the exhaust valve changes. 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, and the piston 8
operation can be made faster.

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 passes through 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. Therefore, 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 helical spline 52 connecting the housing 7 and the piston 8;
A helical spline 53 connects the piston 8 and the rotating shaft 6, and this phase adjustment mechanism 10' also adjusts the movement of the housing 7 and the rotating shaft 6 according to the movement of the piston 8, as in the previous embodiment.
The phase of 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.

C. Effects of the Invention As described above, according to the present invention, the hydraulic chamber facing one axial end of the piston, the hydraulic pressure supply path, and the hydraulic pressure release path are interlocked and connected to the piston and are connected 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 wheel is provided in the housing, the relative rotation amount between the timing wheel and the camshaft is adjusted by moving the piston by an amount corresponding to the amount of movement of the spool. In addition to making it possible to steplessly control the opening and closing timing of the intake valve or exhaust valve, it also reduces the load on the tip of the housing and allows the housing to be supported on a cantilevered structure. It is possible to increase the operating speed by increasing the pressure receiving area of the piston.

[Brief explanation of drawings]

1 and 2 show one embodiment of the present invention, FIG. 1 is a longitudinal sectional view, FIG. 2 is an enlarged sectional view taken along the line -- in FIG. FIG. 3 is a longitudinal cross-sectional view of the embodiment. 1...Camshaft, 4...Pulley as a timing wheel, 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 supply path, 49... Hydraulic release path.

Claims (1)

[Claims] 1 A cylindrical rotating shaft connected to a camshaft; a timing wheel driven from a crankshaft; supported by the rotating shaft to be rotatable about 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 phase adjustment mechanism that interlocks and connects a piston, a housing, and a rotating shaft to change the rotational phase of a timing wheel and a rotating shaft; and a hydraulic chamber facing one axial end of the piston; , a sleeve interlocked and connected to the piston and slidably fitted into the rotating shaft, and a sleeve that is movable relative to the shaft and slidable on the sleeve between the hydraulic pressure supply path and the hydraulic release path. A servo valve consisting of a spool to be fitted is interposed, and the servo valve follows the axial movement of the spool to change the interlocking state between the hydraulic chamber and the hydraulic pressure supply path or the hydraulic release path due to the axial movement of the spool. The bearing and the phase adjustment mechanism configured to be switched to the cut-off state by axial movement of the piston and the sleeve for supporting the housing on the rotating shaft are arranged near the position where the timing wheel is provided on the housing. Features of internal combustion engine valve gear.