JPH1037720A - Clearance adjustment device for valve lifter - Google Patents

Abstract

(57) Abstract: By increasing the surface area of a shim material attached to a valve lifter, the pressing area by a cam can be increased, and the shim material can be attached to the valve lifter extremely easily. Be able to do it accurately. SOLUTION: The whole of a shim material 10 attached to a head of a valve lifter 8 is formed in a substantially cap shape having an upper surface formed as a flat surface and a collar 10a integrally formed on an outer peripheral edge thereof. Then, a fitting groove 8H for tightly fitting the shim material 10 is formed by cutting.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a clearance adjusting device suitable for use as a valve lifter for opening and closing an intake / exhaust valve of an engine.

[0002]

2. Description of the Related Art A valve lifter which opens and closes an intake / exhaust valve of an engine according to rotation of a cam is provided with an appropriate thick shim material for adjusting a gap with the cam at a head portion thereof. An error between the pressing force of the cam against the lifter and the pressing timing is accurately adjusted.

FIG. 4 is a sectional view showing a part of a gasoline engine for an automobile in which a valve lifter provided with a conventional clearance adjusting device is implemented. Includes a cylinder 2 containing a piston 3 and a rod 4, and a cylinder head 5 connected to the cylinder 2. The cylinder head 5 is provided with an intake passage 6 and an exhaust passage 6 'leading to the cylinder 2. ing.

Also, 6A and 6A 'are the passages 6 and 6'.
Are valve seats provided at the intake port and the exhaust port, and 7 and 7 are valves for opening and closing the intake port and the exhaust port. 7S and 7S are shafts of the valves 7 and 7. Each shaft 7S and 7S is It is attached to the cylinder head 5 so as to be able to move up and down in the vertical direction.

[0005] Reference numerals 9 and 9 denote valve springs interposed between the upper end portions 7Sa and 7Sa of the valve shafts 7S and 7S and the mounting grooves 5T and 5T 'formed in the cylinder head 5, respectively. , 9 by constantly popping the valve shafts 7S, 7S in the pulling direction,
A seating force is secured for each valve 7, 7 to close each valve seat 6A, 6A ', that is, the intake port and the exhaust port.

Further, in the drawing, reference numerals 8 and 8 denote left and right valve lifters having a substantially cylindrical cross section. These valve lifters 8 and 8 respectively connect the inner bottom surfaces 8a and 8a of the head to the valve shafts 7S and 7S. With the upper part of the valve springs 9, 9 abutting on the upper end face and inside the cylindrical part,
The valve shafts 7S, 7S are attached to upper ends 7Sa, 7Sa.

Further, 11, 11 'are sprockets 11
The left and right rotating shafts 12 and 12 'that rotate by the movement of the chain 13 spanning the S and 11S' are cams attached to these left and right rotating shafts 11 and 11 '.
When the cams 12 and 12 'push the upper surfaces of the valve lifters 8 and 8 by the rotation of the valve springs 9 and 9, the valve springs 9 and 9'
The valve shafts 7S, 7S are pressed and slid while compressing the air, so that the valves 7, 7 open each port of the intake passage 6 and the exhaust passage 6 '.

Next, the rotation of the rotating shafts 11 and 11 'proceeds, and the cams 12 and 1 for the valve lifters 8 and 8 are moved.
When the pressure of 2 ′ is released, the valve lifters 8, 8 and the valve shaft 7
S, 7S return to the original position shown in FIG. 4, and the valves 7, 7 again close the inlets of the respective passages 6, 6 '. The opening and closing of the left and right cams 12 and 12 'can be performed by opening and closing the left and right rotation shafts
Since it is mounted at a different angle with respect to 11 ', the mechanism is performed with an appropriate time difference.

Reference numerals 20, 20 denote shims attached to the heads of the valve lifters 8, 8 in order to adjust the errors in the pressing force and the pressing timing of the cams 12, 12 'with respect to the left and right valve lifters 8, 8. About 30 types of shim materials 20 having different thicknesses are prepared in advance,
During the assembly process of the engine 1, the cams 12, 1
2 ′, the error between the pressing force and the pressing timing, and the thick shim material 20 necessary for adjusting the error are determined at the same time. The system is configured to be attached to the head or to be attached to the head one by one by hand.

FIG. 5 illustrates a conventional structure relating to the shim member 20. The shim member 20 formed entirely in a thin disk shape is formed by connecting the upper end of a skirt 8S formed in a cylindrical shape. It is configured to be fitted into a circularly recessed fitting hole 8E in the thick head to adjust the gap between the cams 12, 12 'and the valve lifters 8, 8.

[0011]

In the conventional clearance adjusting device constructed as described above, when the fitting hole 8E is formed by cutting in the head surface of the valve lifter 8, an edge 8F is formed on the outer periphery thereof.
Must be formed, so that this fitting hole 8E
The outer diameter dimension X of the shim material 20 to be fitted into the valve lifter 8 becomes smaller than the outer diameter dimension Y of the valve lifter 8, and the pressing area by the cams 12 and 12 'is reduced by the reduced size. ′ And the valve lifters 8, 8 are difficult to adjust, and the push load of the cams 12, 12 ′ cannot be sufficiently dealt with.

When the fitting hole 8E is recessed in the head surface of the valve lifter 8, it is necessary to accurately form both the outer diameter and the depth of the fitting hole 8E. Of the fitting hole 8E so as not to rattle inside the fitting hole 8E.
Since the inner bottom surface of E must be finished to a flat mirror surface, there is a problem that the cutting process is very troublesome and the manufacturing cost is increased.

Furthermore, when the shim 20 formed in a disc shape is inserted into the insertion hole 8E by a robot (vacuum) or by hand, if the center of the shim 20 and the center of the insertion hole 8E are not accurately aligned, Since the edge of the shim material 20 may catch on the outer peripheral edge 8F of the insertion hole 8E and cannot be quickly inserted, there is also a problem that affects automation of assembly work and assembly.

Accordingly, the technical problem of the present invention is to increase the surface area of the shim material attached to the valve lifter,
The area pressed by the cam can be increased, and the shim material can be attached to the valve lifter very easily.
In addition, it is necessary to be able to perform accurately.

[0015]

Means taken by the present invention to solve the above-mentioned technical problems are as follows.

A shim is interposed between a rotating cam and a valve lifter pushed by the cam to open and close an intake / exhaust valve of an engine to adjust a gap between the cam and the valve lifter. The shim material is entirely formed in a substantially cap shape having a flat upper surface and a collar integrally formed on an outer peripheral edge thereof. And forming a fitting groove for tightly fitting the shim material formed in a shape.

According to the above-mentioned means, a substantially cap-shaped shim having an upper surface formed as a flat surface and an outer peripheral edge integrally formed with a collar can be formed very accurately and easily by press working. In addition, the substantially cap-shaped shim material fitted to the head of the valve lifter has a flat head surface as a cam pressing surface, and a large pressing area can be taken. The position adjustment of the valve can be made easy, and the assembly of the engine can be facilitated accordingly, while the pressing load of the cam can be accurately received and the valve can be opened and closed accurately.

Further, in fitting the shim material formed in a substantially cap shape, the fitting hole may be formed by cutting the peripheral surface of the head of the valve lifter by the thickness of the collar of the shim material. Therefore, the manufacturing process for the valve lifter can be significantly simplified, and the manufacturing cost can be reduced. In addition, the shim material formed in a substantially cap shape is simply fitted so as to cover the fitting groove of the valve lifter head from outside. Therefore, the shim material can be attached manually and by a robot very easily and accurately, and the assembling can be automated by assembly work.

As described above, the technical problems described above can be solved by the above-described means, and the problems of the conventional technology can be solved.

[0020]

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a perspective view of a clearance adjusting device for a valve lifter according to an embodiment of the present invention.

FIG. 1 is a sectional view showing a part of an engine provided with a clearance adjusting device for a valve lifter according to the present invention, and its specific structure is the same as that of the conventional example shown in FIG. Therefore, the same members as those shown in FIG. 4 are denoted by the same reference numerals, and the description thereof will be omitted. Here, the configuration of the shim material 10 which is a main part of the present invention and the mounting structure thereof will be described. .

FIG. 2 is a partial cross-sectional front view showing a state before the shim member 10 is mounted on the valve lifter 8, and FIG. 3 is a partial cross-sectional front view showing the mounted state. The entire material 10 is formed in a substantially cap shape in which a front surface and an inner bottom surface 10R are formed into a flat surface by press working, and a downward collar 10a is continuously provided on an outer peripheral edge thereof.

The head 8R of the valve lifter 8 for mounting the shim material 10 has a flat surface and a cutting groove 8H for fitting the collar 10a of the shim material 10 on the outer peripheral edge. When the shim material 10 formed in a substantially cap shape is fitted on the head 8R, the outer diameter Z of the collar 10a and the outer diameter Z of the skirt 8S of the valve lifter 8 are fitted as shown in FIG. The diameters are configured to be substantially the same.

Therefore, according to the valve lifter gap adjusting device of the present invention, the entire surface of the shim material 10 fitted to the head 8R of the valve lifter 8 becomes the pressing surface of the cams 12 and 12 '. And the inner bottom surface 10R of the shim material 10 having a large pressing area.
Then, since the entire lower end surface of the collar 10R receives the pressing force of the cams 12, 12 ', the pressing load of the cams 12, 12' is sufficiently received, and the valves 7, 7 can be opened and closed accurately.

Further, the shim material 10 formed in a substantially cap shape is used.
8H formed in the head 8a of the valve lifter 8
The conventional mounting structure (FIG. 4), in which a thin disc-shaped shim material 20 is fitted and mounted in a recessed hole 8E formed in the head of the valve lifter 8, since the shim material 20 is fitted so as to cover it. Compared to FIG. 5), the shim member 10 can be mounted in an extremely stable state, and the mounting can be performed easily and accurately, either manually or by a robot.

Further, the shim material 10 formed in a substantially cap shape is used.
Can be easily formed by press working. Further, the formation of the fitting groove 8H with respect to the valve lifter 8 can be performed by cutting only the thickness corresponding to the fitting of the collar 10R. Compared to the case where the hole 8E is recessed,
It can be formed much more easily and accurately.

[0027]

Therefore, according to the valve lifter gap adjusting device of the present invention, the error of the gap between the cam and the valve lifter can be adjusted accurately by taking relatively simple means. The advantage of being able to accurately transmit the cam pressing force to the valve lifter side and accurately opening and closing the intake and exhaust valves of the engine is that it has the advantage of being easy to process and assemble and reducing manufacturing costs. In combination with this, the present invention is suitably applied to a valve lifter portion of an automobile engine.

[Brief description of the drawings]

FIG. 1 is a front sectional view showing a part of a gasoline engine equipped with a valve lifter clearance adjusting device according to the present invention.

FIG. 2 is a partial cross-sectional front view showing a state where a shim material, which is a main part of the present invention, is removed from a valve lifter.

FIG. 3 is a partial cross-sectional front view showing a state in which a shim material is attached to a valve lifter.

FIG. 4 is a front sectional view showing a part of a gasoline engine in which the conventional device is implemented.

FIG. 5 is a partial cross-sectional front view showing a state in which a conventional shim material is attached to a valve lifter.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Engine 6 Intake passage 6 'Exhaust passage 7 Valve 8 Valve lifter 8H Fitting groove 9 Valve spring 10 Shim material 10a Collar 12, 12' Cam

Claims (1)

[Claims] A shim material is interposed between a rotating cam and a valve lifter pushed by the cam to open and close an intake / exhaust valve of an engine to adjust a gap between the cam and the valve lifter. In the gap adjusting device, the entire shim material is formed in a substantially cap shape in which an upper surface is a flat surface and a collar is integrally formed on an outer peripheral edge thereof.
A clearance adjusting device for a valve lifter, characterized in that a fitting groove for tightly fitting a substantially cap-shaped shim material is cut into a head of the valve lifter.