JPH11280435A - Variable valve system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To function under an appropriate condition timing control when lift is changed over from a low lift condition to a high lift condition. SOLUTION: In this variable valve system equipped with an outer body 22, an inner body 23 which can be slid to the outer body 22, a regulation member 26 regulating the relative movement between both these bodies 22, 23, an intermediate body 37 arranged between both these bodies 22, 23 and guiding the regulation member 26, a timing member 26 relatively moved according to inertial force accompanied by the driving of a camshaft and sliding and regulating the regulation member 26 according to an engagement condition, and supporting members 51, 52 arranged in the lower part of the intermediate body 37 and supporting a valve shaft 24, fluid stored in a moving space 29 to which the timing member 36 is moved by inertial force is released to a fluid releasing side chamber 53 through communicating holes 37aa, 37ba arranged in the intermediate body 37, thereby leaked fluid may not normally exit in the moving space 29.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a variable valve apparatus for changing the opening / closing timing or lift amount of an intake / exhaust valve by a lifter disposed between a driving cam of a camshaft and a valve shaft. .

[0002]

2. Description of the Related Art As disclosed in Japanese Patent Application Laid-Open No. Hei 8-189316, for example, a variable valve train of this type includes a lifter that slides in a hole formed in a cylinder head of an engine. The upper body of the outer body is in contact with the high-speed cam, and the upper end of the inner body is in contact with the low-speed cam. A plate (a regulating member) that is slidable in a direction orthogonal to the valve shaft and that regulates the relative movement between the outer body and the inner body is supported by the outer body, and the inner body slides in the outer circumferential groove and the outer circumferential groove. A plate arranged in a possible state can be disengaged from the plate, and relative movement in the valve axis direction with the outer turbo body is restricted.

Further, a pressure source is provided for controlling the sliding of the plate in a direction perpendicular to the valve axis. The pressure source moves the plate to a position where it engages with the outer peripheral groove to open and close the valve in a high lift state. It is possible to selectively switch between a mode and a mode in which the valve is opened and closed in a low lift state by sliding the plate to a position where the plate is separated from the outer peripheral groove.

Japanese Patent Application Laid-Open No. 8-42315 discloses that
An upper bottom cylindrical member slidable in a hole formed in a cylinder head of the engine and driven by a driving cam, and a piston and a spring material fluidly operated in the member by two switching devices for changing a lift amount. And a lock member that locks the lift amount restricting member displaced to one of the switching positions by elastically deforming it in accordance with the trajectory of the driving cam. ing.

[0005]

However, in such a lifter of a variable valve operating device, it is difficult to make a timing for switching the lift state, and a plate (a lift amount regulating member) that slides in a direction orthogonal to the valve shaft is used. ) Cannot be expected to operate smoothly.

That is, in Japanese Patent Application Laid-Open No. 8-189316, the switching timing of the lift state depends on the timing of the generation of the hydraulic pressure, and the timing of the sliding of the plate may overlap the timing of the lift of the cam. In this case, the sliding plate interferes with the end of the outer peripheral groove of the inner body at this time.

In Japanese Patent Application Laid-Open No. 8-42315,
A notch for detecting the trajectory of the driving cam is formed in order to take the timing of lift switching, and the notch requires machining of the cam, alignment with the lifter, and the like, which causes an increase in cost.

In order to solve such a conventional problem, the present inventors have proposed the following variable valve gear in Japanese Patent Application No. 9-248719.

This device is arranged so as to be slidable with respect to the outer body which is driven in synchronization with the camshaft, and to be slidable with respect to the outer body. A regulating member that regulates the relative movement between the outer body and the inner body, an intermediate body that is disposed between the outer body and the inner body and guides the regulating member, and a movement that is provided in the axial direction with respect to the outer body or the inner body. It is movable in the space, and moves relative to the outer body or the inner body in accordance with the inertia force accompanying the driving of the camshaft to regulate the slidable time of the regulating member. A timing member that moves in the axial direction to release the regulation of the regulating member, and a valve member that is disposed below the intermediate body and supports the valve shaft. Those having a support member.

However, in this device, the timing of the valve is controlled by moving the timing member away from the regulating member due to the inertial force. However, the moving space in which the timing member moves is substantially a closed space. Fluid leaked from the pressure chamber fills the moving space in which the timing member moves. For this reason, the jumping-up of the timing member is limited by the fluid in the moving space, and the timing control for switching the lift between the low lift state and the high lift state does not function well.

Accordingly, the present invention has been made in view of the above problems, and it is a technical object of the present invention to make the timing control at the time of switching the lift between the low lift state and the high lift state function based on an appropriate state. And

[0012]

The technical measures taken to solve the above-mentioned problems are an outer turbo-day which is driven in synchronization with a camshaft, and which are slidable with respect to the outer turbo-day and which drive the valve. An inner body, a regulating member slidably disposed in the outer body, and a regulating member for regulating relative movement between the outer body and the inner body, and an intermediate member arranged between the outer body and the inner body to guide the regulating member. The body and the outer body or the inner body are movable in a movement space provided in the axial direction with respect to the outer body or the inner body. A timing member that regulates the slidable time and moves in the valve axis direction to release the regulation of the regulating member; In the variable valve device and a supporting member for supporting the valve shaft is disposed, is the chamber by the intermediate body support member formed, is that of providing a passage communicating from the moving space to the chamber.

With the above structure, a passage communicating from the moving space to the chamber formed by the intermediate body and the support member is provided. Therefore, the fluid leaked and accumulated in the moving space in which the timing member moves moves through the passage to the intermediate space. Since the fluid is discharged into the space formed by the body and the support member, the moving space is not filled with the fluid, and the timing control when switching the lift can be performed in an appropriate state.

In this case, if the passage is formed in the intermediate body, the passage can be formed only by adding the machining of the passage of the intermediate body, so that the timing control can function properly by a simple method. It becomes possible.

[0015]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A variable valve operating device according to the present invention will be described with reference to the drawings.

In FIG. 1, a camshaft 12 is rotatably supported by a cylinder head 11 of a vehicle engine. The camshaft 12 is provided with one low-speed cam 13 and high-speed cams 14 and 15 on both sides thereof. I have.

The low-speed cam 13 and the high-speed cam 1
A lifter 20 interposed between the intake / exhaust valves 4 and 15 and a valve shaft 24 of an intake / exhaust valve has an upper bottom cylindrical shape slidably disposed in a hole 21 formed in the cylinder head 11 in the valve axis direction. The outer body 22 is driven by high-speed cams 14 and 15, and the inner body 23 is driven by the low-speed cam 13. Is done. The stem end surface 24a (valve shaft end surface) of the valve shaft 24 is in contact with the lower surface of the inner body 23 via the shim 25, and receives the driving force of the low speed cam 13 at this portion.

The inner body 23 receives the urging force of the compression spring 27 and is urged toward the low-speed cam 13 by a retainer 52 fixed via a cotter fitted into a groove above the valve shaft by the compression spring 27. I have. Further, the outer turbo day 22 receives the urging force of the compression spring 28 by a retainer 51 disposed below the outer turbo day 22 and is urged toward the high-speed cams 14 and 15.

Outer body 22 and inner body 23
An intermediate body 37 constituted by one or a plurality of members (here, members 37a and 37b) is inserted into an annular space formed therebetween. This intermediate body 37
A pair of substantially rectangular plates (restriction members) 26 slidable in the vertical direction with respect to the valve shaft 24 in the guide space formed by 37a and 37b is sandwiched between 37a and 37b and formed in a direction perpendicular to the valve shaft 24. Are arranged in a state guided by the guide surface 37ca. Further, as shown in FIG. 7, communication holes 37aa and 37aa are formed in the intermediate body 37 in the axial direction.
The communication holes 37aa and 37ba are provided at positions to be opened even when the plate 26 slides along the guide surface 37ca (see FIG. 3). The plate 26 defines a chamber (pressure chamber) 30 that receives pressure in the sliding direction of the plate 26 and a chamber 31 that does not normally receive pressure.

In the pressure chamber 30, a side hole 2 of the auterbore 22 is provided through a fluid passage 11 a provided in the cylinder block 11.
Fluid (oil) is introduced through 2a. On the other hand, a compression spring 32 for urging the plate 26 to the left as shown in FIG. 1 is sandwiched in the chamber 31 by a step provided on the side wall of the plate 26, and between the plate 26 and the inner wall of the outer turbo body 22. It is arranged in.

Below the intermediate body 37, a retainer 52 that supports the valve shaft 24 and receives the urging force of the compression spring 27 that urges the inner body 23 upward, and supports the outer peripheral surface of the retainer 51 and raises the outer turbo body 22 upward. A retainer 51 is provided for receiving the urging force of the compression spring 28 for urging.
Between the retainers 51, 52 and the intermediate body 37, the fluid accumulated in the moving space 29, which moves when the timing member 36 of the lifter 20 receives the inertial force, is filled with the intermediate body 37.
There is formed a chamber 53 that is discharged through the communication holes 37aa and 37ba provided in the. This room 53 is a retainer 5
1 is a pressure release chamber for releasing pressure to the outside through a hole provided on the side.

Fluid discharged from an oil pump 40 is supplied to the fluid passage 11a through a fluid supply / discharge valve 41. The fluid supply / discharge valve 41 is controlled by, for example, an engine speed by a controller (not shown). Depending on the pump 4
Supply fluid (oil) from 0 to the fluid path 11a,
A first position for shutting off between the oil pan 42 and the pump 40 and the fluid passage 11a, and a first position for shutting off the supply of the discharge fluid from the pump 40 to the fluid passage 11a and allowing the fluid passage 11a to communicate with the oil pan 42. Switching control is performed between two positions.

As shown in FIGS. 2 and 3, the plate 26 has a fluid pressure in the pressure chamber 30 and a compression spring 22 in the chamber 31.
Is configured to be slidable in a direction orthogonal to the valve shaft 24 by the repulsive force of the valve shaft 24. FIG. 2 shows a state in which the center of the center hole 26C of the plate 26 is shifted leftward from the axis of the shaft portion 23C of the inner body 23, and FIG.
6C shows a state where the center of 6C coincides with the axis of the inner body 23.

The inner body 23 is, as shown in FIG.
It has a disk-shaped upper end portion 23A that comes into contact with the low-speed cam 13, a disk-shaped lower end portion 23B that comes into contact with the shim 25, and a shaft portion 23C that connects these. The lower end portion 23B has an outer diameter larger than the upper end portion 23A. Is small, and the shaft portion 23C is
Even smaller outer diameter.

The center hole 26C of the plate 26 has a larger inner diameter than the lower end 23B of the inner body 23. When the center of the center hole 26C is aligned with the axis of the inner body 23 as shown in FIG. Lower end 23B
Can enter the central hole 26C of the plate 26,
The plate 26 has the inner body 23 at the shaft portion 23C.
Is a regulating member for regulating the movement of the outer turbo day 22.

The plate 26 is provided with a central hole 26C having a diameter in a range shifted by the sliding amount of the plate 26 in the valve axis direction. The center of the central hole 26C is coaxial with the valve shaft 24, and has a first circumferential groove 26A on the outside and a second circumferential groove 26B on the inside in an axially symmetric positional relationship as shown in FIGS. Are formed. This first circumferential groove 26A
And the second circumferential groove 26 </ b> B is the shaft portion 2 of the inner body 23.
The protrusion 36a of the timing member 36 held on 3C is a groove to be selectively engaged. Further, the timing member 36 is an annular member having a projection 36a on the lower side capable of engaging with the first circumferential groove 26A and the second circumferential groove 26B, and is provided inside the upper end portion 23A of the plate 26 and the inner body 23. The space between the formed spaces 29 can be moved in the axial direction. In this case, the protrusion 36 of the timing member 36
a may be any shape as long as it can fit in the first circumferential groove 26A and the second circumferential groove 26B.

Next, the operation of the variable valve train 10 will be described.

As shown in FIG. 4, the variable valve train has a low lift state in which the outer turbo body 22 and the inner body 23 can move relative to each other in the nose region of the high speed cams 14, 15 and the low speed cam 13. And the inner body 23 mutually switch the high lift state in which the relative movement is impossible. In the high lift state before the switching, as shown in FIG. 1, the lower end 23 </ b> B of the inner body 23 is always at a position lower than the plate 26, and the upper ends of the inner body 23 and the outer turbo body 22 coincide with each other. Perform a lift that does not move relatively. In this state, the projection 36a of the timing member 36 is connected to the first circumferential groove 26 of the plate 26.
A is fitted.

When switching from the high lift state to the low lift state, the fluid supply / discharge valve 41 is switched to the first position, and the discharge fluid (oil) of the oil pump 40 is supplied to the fluid passage 11a. Here, the curve indicated by reference numeral 45 in FIG. 5 shows the valve lift state in the high lift state. In this figure, S1 and S2 are the base circle states with the valve completely closed, and S3 is the maximum lift state with the valve fully opened. In the base circle state, the high speed cams 14 and 15 and the low speed cam 13 are in contact with the outer turbo body 22 and the inner body 23 at the tips of the nose regions (portions where the cam diameter is large) of the respective cams.

The curve indicated by reference numeral 46 indicates the cam acceleration, and the cam acceleration coincides with the acceleration of the lifter 20. That is, an upward acceleration is generated at the beginning and immediately before the closing of the valve, and a downward acceleration is generated near the maximum lift state.

With upward acceleration when the lifter 20 moves from the base circular region to the maximum lift state, the projection 36a of the timing member 36 separates from the first circumferential groove 26A due to the inertial force acting on the timing member 36, but the plate 26
Is pressed downward via the intermediate body 37 by the pressing of the outer body 22 by the cam, and therefore does not move in the sliding direction perpendicular to the valve shaft 24. In this case, at an upward acceleration when the lifter 20 shifts from the base circle region to the maximum lift state, the timing member 36 is once separated from the plate 26 by an inertial force.

On the other hand, in the transition from the maximum lift state of the lifter 20 to the base circle, the first half of the base circle area of the high-speed cams 14 and 15 and the low-speed cam 13 is
When the timing member 36 comes into contact with the plate 26, the timing member 36 is separated from the plate 26 and moves in the axial direction within the moving space 29 formed in the axial direction by inertial force. Then, when the high-speed cams 14 and 15 and the low-speed cam 13 reach the base circle regions, the upper end surfaces of the inner body 23 and the outer turbo body 22 coincide with each other, and the outer body 22
Drive force does not work. Since the timing member 36 has detached from the plate 26 before reaching the base circle area, the plate 26 can slide to the right as shown in FIG.
At this time, since the discharge fluid pressure is acting on the pressure chamber 30, the plate 26 is connected to the lower end 23 </ b> B of the inner body 23.
The timing member 36 slides to the right without interfering with the cam, and after the slide, the timing member 36 falls on the plate by its own weight.
6a and the groove 26B of the plate 26 engage.

That is, when the plate 26 is slid rightward (see FIG. 6), the inner body 23 is disengaged from the outer body 22 in the axial direction with the plate 26. The upper body is slidable, and the rotation of the high-speed cams 14 and 15 and the low-speed cam 13 causes the inner body 23 and the outer body 22 to repeat a state in which the relative positions match and a state in which the relative positions are shifted. Becomes As described above, the timing member 36 can surely complete the switching from the high-lift state to the low-lift state regardless of the timing at which the discharge fluid pressure is applied.

Next, when switching from the low lift state to the high lift state, the supply of the discharge fluid pressure is first stopped. When the discharge fluid pressure is no longer applied to the pressure chamber 30, the force of the compression spring 32 of the chamber 31 presses the plate 26 to the left. In the low lift state, when the nose regions of the high-speed cams 14, 15 and the low-speed cam 13 abut on the lifter 20, the relative positions of the inner body 23 and the outer turbo body 22 are shifted. In a state in which an upward acceleration is applied, the timing member 36 jumps up from the plate 26 in the axial direction due to the inertial force, and the engagement with the plate 26 is released. When the base circular regions of the high-speed cams 14 and 15 and the low-speed cam 13 abut against the lifter 20, the inner body 23 is at the lift position coinciding with the outer turbocharger 22, and the lower end 23B of the inner body 23 is in the center hole of the plate 26. The plate 26 is slidable to the left by detaching from the plate 26C. At this time, the plate 26 is slid leftward by the compression spring 32. After the plate 26 slides to the left position,
When the timing member 36 falls on the plate due to its own weight and reaches the base circle area, the projection 3 of the timing member 36
6a engages with the groove 26A of the plate 26 to be in the state shown in FIG.
Is switched to the high lift state in which the relative movement of is stopped.

When switching between the low-lift state and the high-lift state, the timing of the valve is controlled by moving the timing member away from the regulating member by inertia, but the movement space 29 in which the timing member moves has communication holes 37aa and 37aa. 3
Fluid leaked from the pressure chamber 30 or the like does not accumulate in the moving space because it is always in communication with the chamber 53 through which the fluid is opened via the 7ba. Therefore, the timing is not limited by the fluid accumulated in the moving space in which the timing member 36 moves, and the timing control of the lift switching between the low-lift state and the high-lift state can function sufficiently. Since the communication holes 37aa and 37ba may be provided only in the intermediate body 37, the timing control of the valve can be improved by a simple method.

In this apparatus, the switching from the low lift state to the high lift state is performed by setting the plate 2 to the time when the inner body 23 and the outer turbo body 23 coincide with each other.
6, the timing member 36 is disengaged from the plate 26 and the plate 26 is moved, and the protrusion 36 a of the timing member 36
A, 26B). In other words, the plate 26 can be biased in advance from a state before the relative positions of the inner body 23 and the outer body 23 coincide with each other, and the plate 26 is driven by the inner body 23 and the outer body 23 driven in the base region. The inner body 23 and the outer body 22 are slid at the moment when they coincide with each other, without interfering with the inner body 23.
Can be regulated.

Further, when the timing member 36 having inertia is separated from the plate 26 during the lift operation, the state is switched from the high lift state to the low lift state, and the inner body 2 is lifted.
When the timing member 36 moves away from the plate 26 due to the relative position shift between the outer member 3 and the outer turbo-day 22, the low-lift state is switched to the high-lift state. It is possible to regulate the timing of the valve.

[0038]

According to the present invention, an outer body which is driven in synchronization with a camshaft, an inner body which is slidable with respect to the outer body, and an inner body which drives a valve, and which are slidably provided in the outer body. A regulating member that regulates relative movement between the outer turbo body and the inner body, an intermediate body that is disposed between the outer turbo body and the inner body and guides the regulating member, and is provided in the axial direction with respect to the outer turbo body or the inner body. In the moving space, and moves relative to the outer body or the inner body in accordance with the inertia force generated by driving the camshaft to regulate the slidable time of the regulating member and to move in the valve axis direction. A timing member for releasing the regulation of the regulating member, and a supporting member disposed below the intermediate body and supporting the valve shaft. In the valve device, a chamber is formed by the intermediate body and the support member, and a passage communicating with the chamber from the moving space is provided. Thus, a passage communicating from the moving space to the chamber formed by the intermediate body and the support member is provided. The fluid leaked and accumulated in the moving space is discharged through the passage to the space formed by the intermediate body and the support member, and the moving space is not filled with the fluid. For this reason, the timing control at the time of switching between the low lift state and the high lift state can be made to function based on an appropriate state.

In this case, if the passage is formed in the intermediate body, the passage can be formed only by machining the intermediate body, and the timing control can be improved by a simple method.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view illustrating a variable valve operating device of an engine according to an embodiment of the present invention.

FIG. 2 is a sectional view taken along line AA of the lifter shown in FIG.

FIG. 3 is a sectional view of the lifter when the timing member shown in FIG. 2 moves under pressure.

FIG. 4 is a diagram showing a relationship between a switching timing of a variable valve operating device and a trajectory of a cam according to an embodiment of the present invention.

FIG. 5 is a diagram showing a relationship between a lift amount and time and a relationship between cam acceleration and time of the variable valve operating device according to the embodiment of the present invention.

FIG. 6 is a sectional view showing a state where the valve shown in FIG. 1 is opened by a lift.

FIG. 7 is a diagram showing a discharge path of a fluid from a moving space of the variable valve operating device according to the embodiment of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Variable valve gear 12 Camshaft 20 Lifter 22 Outer body 23 Inner body 24 Valve shaft 26 Plate (regulation member) 26A 1st circumferential groove (groove) 26B 2nd circumferential groove (groove) 29 Moving space (space) 36 Timing member 36a Projection 37aa, 37ba Communication hole (passage) 53 chamber (pressure release chamber)

Claims (2)

[Claims] An outer body which is driven in synchronization with a camshaft; an inner body which is slidable with respect to the outer body, and which drives a valve; and which is slidably disposed within the outer body. A regulating member for regulating the relative movement between the outer body and the inner body; an intermediate body disposed between the outer body and the inner body to guide the regulating member; and for the outer body or the inner body. It is movable in a movement space provided in the axial direction,
In accordance with the inertia force accompanying the driving of the camshaft, the movable member moves relative to the outer turbo body or the inner body to regulate the slidable time of the regulating member, and moves in the valve axis direction to regulate the regulating member. And a support member disposed below the intermediate body and supporting the valve shaft, wherein a chamber is formed by the intermediate body and the support member, and the movement to the chamber is performed. A variable valve operating device having a passage communicating from a space. 2. The variable valve apparatus according to claim 1, wherein the passage is formed in the intermediate body.