JPH0586819A - Roller rocker arm for driving engine valve and manufacture thereof - Google Patents

Abstract

PURPOSE:To provide a light roller rocker arm for driving an engine valve in easy manufacturing work. CONSTITUTION:A fixing hole 5 is bored in the approximately intermediate portion of both side plates 1b in a U-shaped grooved arm main body 1 comprising a bottom plate 1a and the side plates 1b bent upward at both edges of the bottom plate 1a. A roller 7 loosely inserted between both side plates 1b is rotatably pivoted by a support shaft 6 which is press-fitted into the fixing hole 5.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a lightweight and easy-to-manufacture roller rocker arm for driving an engine valve and a method for manufacturing the same.

[0002]

2. Description of the Related Art There are various valve operating mechanisms for internal combustion engines. One of them is an end in which one end of a rocker arm is supported by a pivot shaft, a central portion is pressed by a rotating cam, and the other end opens and closes an engine valve. There is a rocker arm of the pivot (swing arm) type.

In this end pivot type rocker arm, the rocker arm and the rotating cam are normally in sliding contact. Since mechanical loss due to frictional resistance is relatively large in such sliding contact, the roller is mounted on the rocker arm. Various roller rocker arms have been proposed in which a roller contact is provided between the cam and the cam so as to make rolling contact with the cam to reduce mechanical loss.

[0004]

In recent years, in order to obtain a high output with an engine having the same displacement, there is a tendency to increase the number of revolutions. For that purpose, a valve gear such as a rocker arm or an engine valve that reciprocates at a high speed is required. Reduces the weight of the entire mechanism,
It is necessary to improve the followability to the cam and reduce the influence of inertial force.

However, the weight of the roller rocker arm is increased as compared with the usual rocker arm by the addition of rollers, and the arm body is made of cast iron, steel, etc.
Since it is cast and forged, the weight of the rocker arm body is naturally limited. Further, the manufacturing of the arm body is troublesome, which is disadvantageous in cost.

The present invention has been made to solve the above-mentioned problems, and it is possible to improve the output performance of the engine by reducing the total weight, and at the same time, to make the roller rocker arm easy to manufacture and the roller rocker arm. It is intended to provide a manufacturing method.

[0007]

In order to achieve the above-mentioned object, the present invention forms a support portion which can be supported by a cylinder head at one end and a pressing portion which abuts the shaft end of an engine valve at the other end. A coaxial mounting hole is formed in a substantially central portion of both side plates of a U-shaped groove-shaped arm body composed of a bottom plate formed from the above and side plates continuously provided on both ends in the longitudinal direction. A roller loosely fitted between the both side plates is rotatably supported by a support shaft supported by the mounting hole. Further, in the method for manufacturing the roller rocker arm described above, a steel material having a required plate thickness is punched to form a bottom plate having a required width and a pair of mounting holes continuously provided at both side edges in the longitudinal direction of the bottom plate. The side plate to be provided, after molding a substantially rectangular intermediate body continuous on the same plane, the both side plates are bent upward to form a U-shaped groove-shaped arm body,
After that, the roller that is loosely fitted between the both side plates is pivotally supported by a support shaft that is inserted through the both mounting holes.

[0008]

According to the roller rocker arm of the present invention, except for the rollers, all are made of plate-shaped steel material.
Significantly lighter than the conventional roller rocker arm,
The inertial mass during high-speed operation can be reduced, and the output performance of the engine can be improved. Further, since the plate material is simply punched and bent, the manufacturing is easy.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The drawings show an embodiment of the present invention in which an arm body (1) is bent into a substantially U-shaped groove and its bottom plate (1
A substantially square through hole (2) is cut in the center of a).
At one end (left end in the drawing) of the arm body (1), there is formed a bottomed support portion (3) which is recessed in a hemispherical shape upward, and at the other end, the central portion is curved in an arc shape. Pressing part that hangs down
(4) is formed.

A pair of mounting holes (5) and (5) facing each other are formed at substantially the centers of both side plates (1b) and (1b) of the arm body (1). The support shaft (6) penetrating to 5) has a roller
(7) is rotatably supported.

Near both ends of the upper edges of the side plates (1b) (1b) are connected by downward U-shaped reinforcing plates (8) (8).

As shown in FIG. 1, the support portion (3) of the arm body (1) is mounted on the upper end of the pivot shaft (11) of the known valve lash adjuster (10) incorporated in the cylinder head (9). It is supported by fitting, and the pressing portion (4) is in contact with the upper end of the shaft portion (12a) of the engine valve (12).

(13) is a pair of cotters externally fitted in the cotter groove at the upper end of the shaft (12a), (14) is a spring retainer externally fitted in the cotter (13), and (15) is , Spring retainer
A valve spring that biases the engine valve (12) upward via (14).

The upper end surface of the roller (7) is in contact with the rotating cam (16) provided above it.

In the above valve operating mechanism, when the rotary cam (16) is rotated, the roller (7) is rotated and the arm body (1) is vertically swung about the pivot shaft (11), whereby the engine is rotated. The valve (12) is opened and closed. Next, the manufacturing procedure of the roller rocker arm of the above embodiment will be described.
First, a steel material having a required plate thickness is punched by a lower die and an upper die of a pressing device (not shown) to form an intermediate body having the same shape as the developed shape of the arm body (1), that is, as shown in FIG.
A bottom plate (1a) with a predetermined width and a through hole (2) formed in the approximate center
And the side plates (1b) and (1b) provided with a pair of mounting holes (5) (5), which are continuously provided on both side edges of the bottom plate (1a) in the longitudinal direction, are continuous on the same plane, and the bottom plate At both ends of (1a), a substantially rectangular intermediate body (17) is formed in which a supporting portion (3) recessed into a hemispherical shape and an arc-shaped pressing portion (4) are formed.

Next, both side plates (1b) in the intermediate body (17)
Is bent at a right angle upward along the bending position indicated by the imaginary line X, that is, along the extension line of the opening edge in the longitudinal direction of the through hole (2) to form a U-shaped groove as shown in FIG. Eggplant arm body (1)
To form.

After that, the roller loosely fitted between both side plates (1b)
(7) is rotatably supported by a support shaft (6) press-fitted into both mounting holes (5) and (5). Finally, if the reinforcing plates (8) and (8) are fixed to the upper edges of the side plates (1b) and (1b), a roller rocker arm as shown in FIG. 1 is obtained.

Incidentally, a hard metal may be fixed to the supporting portion (3) and the pressing portion (4) to enhance the strength and rigidity and to improve the abrasion resistance. In the manufacturing procedure described above, the mounting hole (5) may be formed after bending the side plates (1b). Further, the support shaft (6) of the roller (7) may be set to the upper side and the through hole (2) through which the lower end of the roller is inserted may be omitted.

[0019]

According to the roller rocker arm of the present invention, since the arm body is formed by bending the plate material, the roller rocker arm is significantly lighter than the conventional roller rocker arm, and the inertial mass during operation is small. The cam followability is improved. As a result, the allowable rotation speed of the engine can be increased and the maximum output can be improved. Further, it can be manufactured quickly and inexpensively by press working or the like.

[Brief description of drawings]

FIG. 1 is a central vertical sectional front view of a valve operating mechanism to which a roller rocker arm of the present invention is applied.

FIG. 2 is a view taken along the line AA of FIG.

FIG. 3 is an exploded perspective view showing a manufacturing procedure of the arm body.

FIG. 4 is a plan view showing a manufacturing procedure of the arm main body.

[Explanation of symbols]

(1) Arm body (1a) Bottom plate (1b) Side plate (2) Through hole (3) Support part (4) Pressing part (5) Mounting hole (6) Spindle (7) Roller (8) Reinforcing plate (9) Cylinder head (10) Valve lash adjuster (11) Pivot shaft (12) Engine valve (12a) Shaft (13) Cotter (14) Spring retainer (15) Valve spring (16) Rotating cam (17) Intermediate

Claims (2)

[Claims] 1. A bottom plate having a support portion capable of supporting a cylinder head at one end and a pressing portion abutting the shaft end of an engine valve at the other end, and upwardly extending at both longitudinal edges thereof. A U-shaped groove-shaped arm body composed of a side plate continuously connected to the both side plates is provided with a coaxial mounting hole, and a roller loosely fitted between the both side plates is provided with the mounting hole. A roller rocker arm for driving an engine valve, which is rotatably supported by a support shaft supported by. 2. A bottom plate having a required width is punched out from a steel material having a required plate thickness, and side plates provided with a pair of mounting holes at appropriate positions are continuously provided on both side edges of the bottom plate in the longitudinal direction. After molding a substantially rectangular intermediate body continuous on a plane, the both side plates are bent upward to form a U-shaped groove-shaped arm body, and then a roller loosely fitted between the both side plates. To
A method for manufacturing an engine valve driving roller rocker arm, characterized in that the roller rocker arm for driving an engine valve is pivotally supported by a support shaft that passes through both the mounting holes.