JPH10299442A - Variable valve device for engine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To perform reliable switching operation of a lift amount of a valve stem at low cost and stabilize lift operation of the valve stem. SOLUTION: A lifter 20 comprises an outer body 22 slid in a hole, formed in the cylinder head of an engine, and driven by a drive cam; and an inner body 23 slidably held at the outer body 22 and driving a valve. A plate 26 slidably supported in the outer body 22 is regulated by a timing pin 35 slidably held by the inner body 23 or the outer body 23. The timing pin 35 is formed of a metal disposed between a spring 34 and a position control member 33 and having inertia action. When the timing pin does not follow changes in axial acceleration of the lifter 20 through inertia action and is separated away from the position control member 33, the plate 26 is moved.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

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

[0002]

2. Description of the Related Art As a prior art of such a variable valve operating device, there is, for example, JP-A-8-42315. A lifter of a variable valve operating device typified by the publication discloses an upper bottom cylindrical member that slides in a hole formed in a cylinder head of an engine and is driven by a driving cam, and a member inside the upper bottom cylindrical member. A lift amount regulating member which is displaceably held under the action of a piston and a spring member which are fluidly operated at two switching positions for changing the lift amount, and the lift amount regulating member which is displaced to one of the switching positions. And a lock member that locks by elastically deforming according to the trajectory of the drive cam.

In the lifter of this variable valve operating device, the lift amount of the valve is changed in accordance with the switching position of the lift amount regulating member to correspond to the operating state of the engine.

[0004]

Since the conventional variable valve operating device of the engine has means (cam groove and cam contact member) for detecting the trajectory of the driving cam in response to switching of the lift amount,
Processing becomes complicated. Further, the lift amount regulating member is displaced in a direction orthogonal to the valve shaft direction, and the support surface supporting the valve shaft end surface slides on the valve shaft end surface. In such a configuration, it is difficult to imagine that the entire valve shaft end surface is in contact with the support surface, and there is a high possibility of one end contact. In this case, there is a weak point that a lateral load is easily applied to the valve due to uneven wear of the valve shaft end surface. Further, since the hole for the means for detecting the trajectory of the drive cam is provided at the center of the lifter, the surface pressure at the time of the maximum lift is reduced.

SUMMARY OF THE INVENTION Accordingly, it is an object of the present invention to solve the above-mentioned problems and to make it possible to detect the timing of lift switching with a simple configuration without detecting the position of the cam.

[0006]

SUMMARY OF THE INVENTION The present invention has a camshaft and a valve which is driven to open and close via a lifter by the camshaft, and the camshaft includes a driving cam for driving the valve and a timing cam. The present invention is applied to a variable valve train of an engine having the same. That is, according to the present invention, in the variable valve operating device of the engine, the lifter slides in a hole formed in a cylinder head of the engine and is driven by the camshaft. An inner body that is slidably held in the outer body and is slidably supported in the outer body, and a regulating member that regulates relative movement between the outer body and the inner body; A timing pin which is held and moves relative to the outer turbo body in accordance with an inertial force accompanying the driving of the inner body to regulate a slidable time of the regulating member.

[0007] The variable valve operating device for an engine according to the present invention comprises:
The present invention can also be applied to a variable valve train of an engine having a camshaft having a high-speed cam, a low-speed cam, and a timing cam provided adjacently, and a valve that is opened and closed by the camshaft via a lifter. In this case, the lifter slides in a hole formed in the cylinder head of the engine and is driven by either the high-speed cam or the low-speed cam. An inner body held and driven by the other of the high-speed cam and the low-speed cam; a regulating member slidably supported by the outer turbo body and regulating relative movement between the outer turbo body and the inner body; A timing pin that is slidably held on one of the body and the inner body and that relatively moves with respect to the one in accordance with an inertial force accompanying the driving of the one to regulate the slidable time of the regulating member. One of the outer body and the inner body drives the valve without passing through the other, and the other drives the valve via one. The It is an characterized.

[0008]

In the variable valve system for an engine according to the present invention, the lift amount is changed by the relative movement between the outer body and the inner body in the cylinder head hole. This relative movement is regulated by a regulating member slidably supported in the outer turbo day. Sliding of the regulating member is regulated by a timing pin slidably held on the inner body or the outer body. When the lifter is driven in the axial direction by the drive cam, the timing pin is temporarily separated from the regulating member due to the inertia associated with the lifter. Stipulates the switching time.

According to the variable valve operating device for an engine according to the present invention, the switching timing can be specified only by providing the timing pin in the lifter without detecting the cam trajectory, and the machining of the cam is also omitted. As a result, not only can the cost be reduced, but also the stability of the valve lift operation can be obtained. The regulating member is
Instead of sliding directly on the end face of the valve shaft, the inner body is always in contact with the end face of the valve shaft, thereby avoiding the problem of one-sided contact and uneven wear.

[0010]

BEST MODE FOR CARRYING OUT THE INVENTION In the variable valve operating system for an engine according to the present invention, when one driving cam for lift is provided on a camshaft, the lift amount is changed by relative movement between an outer turbo body and an inner body. It can be configured. The variable valve operating device for an engine according to the present invention, even when a high-speed cam and a low-speed cam are provided on a camshaft,
By configuring the outer turbo body and the inner body to drive the outer turbo body by one of the high-speed cams and the other by driving the inner body, one of the outer turbo body and the inner body can be driven without passing through the other. And the other can drive the valve via one.

The timing pin is a heavy weight member having inertia, and may be of any type so long as it is guided in the axial direction and engages with the regulating member. It is preferable that a spring is provided between the timing pin and the regulating member. The spring ensures engagement between the regulating member and the timing pin.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, a specific example of a variable valve operating device for an engine according to the present invention will be described with reference to the drawings.
In the variable valve operating device 10 of the engine shown in FIG. 1, a camshaft 12 is rotatably supported by a cylinder head 11 of an engine (not shown). High-speed cams 14, 15 are arranged on both sides.

The lifter 20 has an upper bottom cylindrical outer turbocharger 22 slidably disposed in a hole 21 formed in the cylinder head 11 in the valve axial direction. Inner body 2 slidably held in
3 and a lifter body 2
2 is driven by the high speed cams 14 and 15, and the inner body 23 is driven by the low speed cam 13. The stem end surface 24a (valve shaft end surface) of the valve shaft 24 is
, And comes into contact with the lower surface of the inner body 23, thereby receiving the driving force of the low-speed cam 13. The outer turbo day 22 is urged toward the high speed cams 14 and 15 by a compression spring 28. Note that an annular shim is provided on the upper end surface of the outer turbo day 22.

Inside the lifter 20, an outer turbo 2 is provided.
An intermediate body 37 is provided in the space between the inner body 2 and the inner body 23.
Is fitted to form an annular chamber, and the chamber is formed in the pressure chambers 30 and 31 by the plate 26 engaged with the outer peripheral groove 23a while being guided by the outer peripheral groove 23a (FIG. 1) of the inner body 23. Be partitioned. One of the pressure chambers 30 is connected to the fluid passage 11 a of the cylinder block 11 through
Fluid is introduced through the second side hole 22a, and a compression spring 32 is disposed in the other pressure chamber 31. The fluid passage 11a
The fluid discharged from the oil pump 40 is supplied through the fluid supply / discharge valve 41. The fluid supply / discharge valve 41 supplies, for example, a discharge fluid from the pump 40 to the fluid passage 11a according to the engine speed by a controller (not shown), and shuts off the oil pan 42 from the pump 40 and the fluid passage 11a. The switching control is performed between the first position and the second position where the supply of the discharge fluid from the pump 40 to the fluid passage 11a is interrupted and the fluid passage 11a communicates with the oil pan 42.

The plate 26 is an annular member having a central hole 26a substantially coinciding with the peripheral opening surface of the outer peripheral groove 23a. The plate 26 intersects the valve axial direction by comparing the pressure of the fluid with the pressing force of the compression spring 32. It becomes possible to move in the horizontal direction. When the pressure of the fluid is not applied to the pressure chamber 30, the plate 2
6 moves to the left in FIG. 1 (also in FIG. 2). Plate 26
Prevents the relative movement between the outer body 22 and the inner body 23 at this left position. When the pressure of the fluid is applied to the pressure chamber 30, the plate 26 moves to the right in FIG. 1 to enable the relative movement between the outer body 22 and the inner body 23. The plate 26 corresponds to the regulating member of the present invention.

In FIG. 2, a position control member 33 extending along the moving direction of the plate 26 is fixed to the plate 26 inside the lifter 20. The position control member 33 has two positioning holes 33a and 33b. Above the position control member 33, there is provided a pin 35 whose distal end faces the positioning holes 33a and 33b and whose proximal end is held by a spring 34, as shown in FIGS. As shown in FIG. 1, the spring 34 can freely expand and contract in the valve axis direction.
Is supported between. The pin 35 is preferably made of a metal having a large specific gravity, such as lead or brass, and is preferably provided with a guide. The pin 35 corresponds to the timing pin of the present invention.

The relative movement of the outer body 22 and the inner body 23 is restricted by a spring 36.
That is, a downward shoulder 22b is provided on the inner wall of the hole of the outer body 22 on which the inner body 23 slides, while an upward shoulder 23b is provided on the inner body 22.
The spring 36 is arranged between the outer body and the shoulder 23a, and urges the inner body 23 in a direction of pushing down the outer body 23 with respect to the outer body.

[0018]

[Description of Operation] In the variable valve operating device for an engine having the above-described configuration, the nose region B of the high-speed cams 14, 15 or the low-speed cam 13 (hereinafter, abbreviated as cam) shown in FIG.
Then, an operation is performed to switch the outer turbo body 22 and the inner body 23 between the relative movable state and the relative non-movable state. Now, when the pressure is not applied to the pressure chamber 30 and the relative movement is not possible, the pin 35 is moved to the positioning hole 33b.
It shall be fitted to. When the nose area of the cam that rotates clockwise in FIG.
Are driven downward with increasing acceleration. However, pin 35
The spring 34 contracts and only the position control member 33 integral with the lifter 20 escapes from the pin 35 because of the inertia that attempts to stay at that height position due to inertia. For this reason, the pin 35 fitted in the positioning hole 33b is
, The plate 26 cannot move the outer body 22 and the inner body 23 relative to each other only by the force of the compression spring 32. At this time, if the pressure of the fluid is applied, the plate 26 can be moved rightward in FIG.
Are engaged with the positioning holes 33a, and the outer body 22 and the inner body 23 are switched to a state in which they can relatively move. As a result, the state is switched to a state in which the lift amount corresponding to the difference in size between the low speed cam 13 and the high speed cams 14 and 15 of the lift 20 is displaced. The low-speed cam 13 and the high-speed cams 14 and 15 of this embodiment have the same base circle area and differ only in the size of the nose.

Further, the switching can be performed in the latter half of the nose area B. In this case, at the moment when the lifter 20 changes the direction from the bottom dead center to the top dead center, the acceleration direction of the lifter 20 is reversed, and the pin 35 moves upward together with the lifter 20 while being fitted to the positioning pin 33b. . However, when the movement of the lifter 20 is reversed near the tip of the nose area B and the acceleration is forcibly reduced, the pin 35 has the acceleration at the tip of the nose area because there is no forcibly reduced acceleration. The position control member 33 is pressed. Due to this reaction, the pin 35 moves upward faster than the lifter 20 and the spring 3
4 is contracted and pulled out from the positioning hole 33b.

As described above, in the variable valve apparatus of the engine according to the present embodiment, the pin 35 having the inertial action disposed between the spring 34 and the position control member 33 changes the axial acceleration of the lifter due to the inertial action. The plate 26 which is a regulating member is not
The switching time can be defined without detecting the trajectory of the cam.

Further, even if the plate 26 is displaced in a direction perpendicular to the valve shaft direction, the plate 26 does not slide on the valve shaft end surface because the support surface for supporting the valve shaft end surface is an inner body. Thus, the valve shaft can be correctly lifted in the axial direction without causing the problem of one-side contact. Further, since the lifter receives the driving force of the cam on the entire upper surface, there is no problem of a decrease in surface pressure even during the maximum lift.

In the above-described embodiment, the present invention is applied to a variable valve operating system of an engine having a high-speed cam and a low-speed cam, and the lift amount of the valve is made variable by the two cams. It is possible to apply the present invention to a variable valve train of an engine having a mechanism capable of stopping a lift. At this time, as shown in FIG. 6, the low-speed cam 13 (nose) of the above-described embodiment may be abolished, and the nose heights of the high-speed cams 14 and 15 may be appropriately reduced. According to this, when the relative movement between the outer body 22 and the inner body 23 is regulated by the plate (regulating member) 26, the high-speed cams 14 and 1 of the above-described embodiment in which the nose height is appropriately set are set.
5, when the relative movement between the outer body 22 and the inner body 23 is not restricted by the plate (restriction member) 26, the valve lift is stopped.

[Brief description of the drawings]

FIG. 1 is a sectional view showing a variable valve train of an engine according to the present invention.

FIG. 2 is a sectional view showing the lifter along the line AA in FIG. 1;

FIG. 3 is a cross-sectional view showing a position control member along the line AA in FIG. 2;

FIG. 4 is a cross-sectional view showing a state in which a timing pin is engaged with a position control member of a regulating member.

FIG. 5 is a diagram showing a relationship between a switching timing and a cam trajectory.

FIG. 6 is a sectional view of another embodiment of the variable valve operating device for an engine according to the present invention.

[Explanation of symbols]

10: Variable valve gear, 11: Cylinder block, 12:
Cam shaft, 13: low speed cam, 14, 15: high speed cam, 20: lifter, 22: outer turbo body, 23 inner body, 23a: outer peripheral groove, 24: valve shaft, 26: plate (regulating member), 30, 31: Pressure chambers 30, 32: Compression spring, 33: Position control member, 34: Spring, 35
... Timing pins.

Claims (2)

[Claims] 1. A variable valve actuating device for an engine having a camshaft and a valve which is driven to open and close via a lifter by the camshaft, wherein the lifter slides in a hole formed in a cylinder head of the engine. An outer body driven by the camshaft, an inner body slidably held by the outer body and driving the valve, and an outer body and the inner body slidably supported in the outer body. A regulating member that regulates relative movement of the outer body, and a slidable time of the regulating member that is slidably held by the outer body and moves relative to the outer body in accordance with an inertia force caused by driving of the inner body. And a timing pin that regulates the pressure of the engine. 2. A variable valve actuation device for an engine, comprising: a camshaft having a high-speed cam and a low-speed cam provided adjacent to each other, and a valve that is opened and closed by the camshaft via a lifter. An outer turbo-day slidable in a hole formed in a cylinder head of the engine and driven by one of the high-speed cam and the low-speed cam; and the high-speed cam slidably held by the outer turbo-day. And an inner body driven by the other of the low-speed cam and a regulating member slidably supported by the outer turbo body and regulating relative movement between the outer turbo body and the inner body,
Timing for regulating the slidable time of the regulating member by slidably held by one of the outer turbo body and the inner body and relatively moving with respect to one of the outer body and the inner body in accordance with an inertial force accompanying the driving of the other. A variable valve of an engine, wherein one of the outer turbo body and the inner body drives the valve without passing through the other, and the other drives the valve via one. apparatus.