JPH06159016A - Valve lifter of internal combustion engine - Google Patents

Abstract

PURPOSE:To obtain a structure which has a cylinder with a long size and a thin thickness, and can apply a crowning easily, in a valve lifter. CONSTITUTION:In a valve lifter of an internal combustion engine provided with a roller 1 rotating contacting to the cam of a camshaft, a roller holder 2 to hold the roller 1 rotatable through a roller holding shaft 4, and a cylinder 3 to slide in a shaft hole formed to a cylinder block in the condition to stop the rotation by a guide pin, the roller holder 2 and the cylinder 3 are formed in separate bodies. As a result, since the cylinder 3 can be manufactured with a steel pipe, for example, the manufacturing is made easier, and when the remaining roller holder 2 is manufactured by a forging, the forging process of the valve holder 2 can be also carried out simply.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a valve lifter which constitutes a valve device of an internal combustion engine, and more particularly to a structure of a main body composed of a roller holding portion and a cylindrical portion.

[0002]

2. Description of the Related Art A valve lifter moves a push rod up and down in synchronism with the rotation of a camshaft, and its conventional structure is shown in FIGS. 3 is a vertical sectional side view showing the valve lifter and its mounting portion, and FIG. 4 is a vertical sectional front view of the valve lifter.

In FIG. 3, reference numeral 11 is a camshaft,
Reference numeral 12 is a cam, 13 is a cylinder block, 14 is a lifter hole formed in the cylinder block 13, 15 is a push rod, 16 is a guide pin, and 17 is a valve lifter.

As shown in FIGS. 3 and 4, the valve lifter 17 includes a roller 18, a roller holding portion 19, and a cylindrical portion 20. The roller 18 is in contact with the cam 12 and rotates. The roller holding portion 19 is in the shape of a fork, and the roller 18 is rotatably held between the forked portions via a roller support shaft 21. The cylindrical portion 20 is
The cylindrical wall has a guide hole 22 in the longitudinal direction, which is slidably inserted into the lifter hole 14, and the inner bottom surface thereof receives the lower end portion of the push rod 15. The cylindrical portion 20 has the guide pin 16
Is prevented from rotating by penetrating the cylinder block 13 and being inserted into the guide hole 22.

[0005]

By the way, in the conventional valve lifter 17, the portion excluding the roller 18 and the roller support shaft 21, that is, the main body including the roller holding portion 19 and the cylindrical portion 20 is formed from one material block. It is made by forging. In this main body, in order to make the sliding inside the lifter hole 14 smooth, the cylindrical portion 20 is lengthened to deepen its internal depth, and for the purpose of weight reduction, the wall thickness of the cylindrical wall of the cylindrical portion 20 is increased. It is pointed out that if it is attempted to reduce the thickness, it will be difficult to process it, and it will not be possible to easily manufacture one that slides smoothly and one that is lightweight.

Further, in use, since the valve lifter receives a force in the direction in which the valve lifter is tilted in the lifter hole 14 due to the contact with the cam 12, the upper and lower peripheral edges of the cylindrical portion 20 in strong contact with the inner peripheral surface of the lifter hole 14 are affected. It is desirable to perform crowning, but in the conventional case, the shape of the main body is not vertically symmetrical and is complicated, so that the above-described crowning process is difficult.

Further, in the conventional valve lifter, the roller support shaft 21 for supporting the roller 18 has a structure in which the fork-shaped bifurcated portion of the roller holding portion 19 penetrates left and right.
In order to prevent the roller support shaft 21 from slipping out, conventionally, the exposed end surfaces of the roller support shaft 21 are crimped on both sides of the roller holding portion 19, but the caulked portion is likely to sag after long-term use. It is pointed out that the reliability is low.

An object of the present invention is to solve the above-mentioned problems, and an object thereof is to provide a structure having a long cylindrical portion having a small wall thickness and capable of easily crowning. Another object of the present invention is to provide a structure in which the roller support shaft is not crimped, and to prevent the roller support shaft from coming off for a long period of time.

[0009]

In order to achieve the above object, the present invention provides a roller that rotates in contact with a cam of a cam shaft, and a roller that rotatably holds this roller via a roller support shaft. A valve lifter for an internal combustion engine including a holding portion and a cylindrical portion that slides in a lifter hole formed in a cylinder block while being prevented from rotating by a guide pin has the following configuration.

In the valve lifter of the present invention, the roller holding portion and the cylindrical portion, which are separately formed, are integrated. The valve lifter has one end in the lengthwise direction of the cylindrical portion fitted over the roller holding portion by press fitting, and the press fit margin of the cylindrical portion with respect to the roller holding portion is exposed to the exposed end surface of the roller support shaft of the roller holding portion. It is preferable to set so as to extend to.

[0011]

[Operation] By making the roller holding portion and the cylindrical portion separate,
Since the cylindrical portion can be manufactured from a pipe such as a steel pipe, the length and the wall thickness can be freely set, and the peripheral edges of both ends of the roller holding portion can be crowned before the roller holding portion is joined.

Further, by deepening the press-fitting margin of the cylindrical portion with respect to the roller holding portion, both ends of the roller support shaft can be pressed by a part of the cylindrical portion, which prevents the roller support shaft from slipping out.

[0013]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The details of the present invention will be described below with reference to an embodiment shown in FIG. FIG. 1 shows a valve lifter according to an embodiment of the present invention.

The valve lifter according to this embodiment includes a roller 1 that rotates in contact with a cam of a cam shaft (not shown), a roller holding portion 2 that rotatably holds the roller 1, and a lifter of a cylinder block (not shown). Cylindrical part 3 sliding in the hole
It is the same as the conventional valve lifter in that it is provided with and. In addition, reference numeral 4 is a roller support shaft for pivotally supporting the roller 1 on the roller holding portion 2, and reference numeral 5 is a guide hole into which a rotation stopping guide pin is inserted.
Is formed on the intermediate portion 3b in the length direction.

The valve lifter of this embodiment is different from the conventional valve lifter in that the roller holding portion 2 and the cylindrical portion 3 are molded separately.

The roller holding portion 2 is formed by forging into a fork shape, has a concave portion for receiving a push rod on the end surface of the base portion, and one end side in the length direction of the cylindrical portion 3 is externally press-fitted into the base portion. Are combined by.

The cylindrical portion 3 is composed of a cylindrical steel pipe, and among the longitudinal portions 3a, 3b, 3c, the longitudinal intermediate portion 3b including the guide hole 5 is bulged to form the end portions 3a, 3b. The diameter is smaller than 3c. In this cylindrical portion 3, the outer circumferences of both end portions 3a, 3c are polished and the peripheral edges of the upper and lower ends are subjected to crowning in a single stage. By the way, the intermediate portion 3b of the cylindrical portion 3
If the diameter is reduced to a small diameter, the strength can be increased as compared with the conventional example shown in FIG.
Since b is not polished, deformation due to polishing does not occur at all.

In the above structure, the length and wall thickness of the cylindrical portion 3 can be freely set by selecting the steel pipe to be the cylindrical portion 3, and the cylindrical portion 3 is made long and thin. It is possible to obtain a valve lifter that is lightweight and slides smoothly in the lifter hole. In addition, since the cylindrical portion 3 is a substantially vertically symmetrical cylindrical body before being coupled with the roller holding portion 2,
It is possible to easily perform the crowning process, and by this crowning process, a valve lifter that does not easily wear can be obtained.

2A and 2B show a valve lifter according to another embodiment of the present invention. FIG. 2A is a side view and FIG. 2B is a vertical sectional front view. In this embodiment, a part 3d of the cylindrical portion 3 is press-fitted on both sides of the roller holding portion 2 to a depth reaching the exposed end surface of the roller support shaft 4.

Specifically, in the cylindrical portion 3, portions located on both sides of the roller holding portion 2 on the press-fitting side of the roller holding portion 2 are extended outward in the axial direction as leg portions 3d, and the leg portions 3d are formed. Covers the exposed end surface of the roller support shaft 4. That is, since both ends of the roller support shaft 4 are pressed by the leg portions 3a of the cylindrical portion 3, the roller support shaft 4 is prevented from coming out of the roller holding portion 2 without crimping as in the conventional case.

The roller holding portion 2 and the cylindrical portion 3 may be joined by welding instead of press fitting. In addition, a part of the cylindrical portion 3 does not necessarily have to cover the entire end surface of the roller support shaft 4, and it is sufficient that it covers at least a part of the end surface of the roller support shaft 4. In addition, when the roller 1 has a small diameter and is large enough to fit inside the cylindrical portion 3, the cylindrical portion 3 can be molded into a tubular body without the leg portions 3d.

[0022]

As described above, according to the present invention, since the roller holding portion and the cylindrical portion are separate bodies, the length and wall thickness of the cylindrical portion can be freely set, and the length can be increased. A valve lifter having a thin cylindrical portion can be easily manufactured. Further, since the crowning process can be applied to the peripheral edges of both ends of the cylindrical portion before the cylindrical portion is joined to the roller holding portion, wear is less likely to occur and a valve lifter that smoothly slides in the lifter hole can be obtained.

Further, if the press-fitting margin of the cylindrical portion and the roller support shaft is specified, it is possible to reliably prevent the roller support shaft from slipping out for a long period of time without the need for troublesome caulking as in the conventional case.

[Brief description of drawings]

FIG. 1 is a vertical sectional front view of a valve lifter according to an embodiment of the present invention.

2A and 2B show a valve lifter according to another embodiment of the present invention, in which FIG. 2A is a side view and FIG. 2B is a vertical sectional front view.

FIG. 3 is a vertical sectional side view showing a conventional valve lifter and its mounting portion.

FIG. 4 is a vertical sectional front view of the conventional valve lifter.

[Explanation of symbols]

 1 Roller 2 Roller Holding Part 3 Cylindrical Part 3d Leg Part 4 Roller Support Shaft

Claims (2)

[Claims] 1. A state in which a roller that rotates in contact with a cam of a camshaft, a roller holding portion that rotatably holds the roller, and a lifter hole formed in a cylinder block are prevented from rotating by a guide pin. 1. A valve lifter for an internal combustion engine, comprising: a cylinder portion that slides with respect to each other; and a roller holding portion and a cylinder portion, which are separately formed, are integrated with each other. 2. The valve lifter according to claim 1, wherein one end of the cylindrical portion in the lengthwise direction is externally fitted and press-fitted into the roller holding portion to be coupled to each other, and the press-fitting margin of the cylindrical portion with respect to the roller holding portion is the roller holding portion. A valve lifter for an internal combustion engine, which extends to the exposed end surface of the roller support shaft.