JP2663084B2 - Method of manufacturing rocker arm with roller - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a rocker arm used for a valve train of an internal combustion engine, and more particularly to a method for manufacturing a swing arm type rocker arm with rollers.

[0002]

2. Description of the Related Art In recent valve operating mechanisms, a rocker arm with a roller, which receives a pressing force of a cam by a roller, has been adopted, so that fuel consumption is improved by reducing friction and noise is reduced. Is now possible. Most of the rocker arms with rollers are of a cast or forged type as shown in FIGS. The rocker arm 51 with a roller shown in the figure is formed by casting or forging a main body 52, then cutting a large and deep flat square mounting hole 53 and other parts, arranging a roller 54 in the mounting hole 53, and rotating. It is manufactured by the method of attaching it as much as possible.

However, in the above-described manufacturing method, the number of steps of the cutting process is very large, and the cutting of the mounting hole 53 is particularly difficult, so that the manufacturing cost is high. In addition, since there are many cutting points, the processing shape is limited,
Optimal design for weight reduction was difficult. Further, in the forging type, there is a problem that the fiber flow during forging of the material is cut when the large and deep mounting hole 53 is cut, so that the strength during forging cannot be maintained.

Therefore, as shown in FIGS. 13 and 14,
Rocker arm 55 of a sheet metal boat type that does not require cutting
However, there has been a problem that it is impossible to form a screw portion for screwing a pivot shaft (not shown) or a fork portion for sandwiching the outer peripheral surface of the end portion of the valve stem.

[0005] The applicant of the present invention has previously described FIGS.
Rocker arm with roller 5 of sheet metal bending type as shown in 5
6 (JP-A-63-272903).
Since the thickness of the sheet metal is constant, the thickness of each part cannot be freely changed, and there is a problem that a compact design is difficult due to the welding structure.

SUMMARY OF THE INVENTION An object of the present invention is to solve the above-mentioned problems, reduce the number of cuts, and increase the degree of freedom in designing the machining shape. Therefore, the optimum design for weight reduction is facilitated, and the manufacturing cost is reduced. Another object of the present invention is to provide a method of manufacturing a rocker arm with a roller, which can obtain high strength.

[0007]

In order to achieve the above object, a method of manufacturing a rocker arm with a roller according to the present invention comprises: a base end serving as a tilt center of the rocker arm; a tip end for pressing a valve stem; A middle portion that is continuous between the portion and the tip portion, and a pair of side portions that are continuous on both sides of the middle portion, a process of forging to a required developed shape by changing the thickness of the material from the material and A step of punching the peripheral portions of the pair of side portions into a required peripheral shape, a step of bending the pair of side portions so as to be upright to form both side walls of the rocker arm, and a step of the bending process. After that, a step of punching the intermediate portion to form a through hole, and arranging a roller receiving a pressure of a cam between the side walls and in the through hole, and rotatably mounting the roller to the both side walls. And a step.

In the first forging process, at the base end,
For example, forging a spherical concave portion with which the pivot comes into contact, or forging a fork portion at the tip end, for example, a pad surface with which the valve stem comes into contact with the end surface, or a fork portion that sandwiches the end outer peripheral surface of the valve stem. Can be.

[0009]

[Action] Required for forging by changing the thickness of the material
Forging into the developed shape of the
The degree increases. Also, after bending a pair of side parts,
Since the through hole is formed by punching the middle part,
Around the through hole during bending that occurs when the steps are repeated
Does not occur. Further, the space for disposing the rollers can be formed by bending the side portion and punching the intermediate portion, so that the mounting hole does not need to be cut as in the conventional forging type. For this reason, the number of immediate points decreases. In addition, compared to the conventional large and deep mounting holes, the through holes formed by punching the middle part are shallower, so the fiber flow during forging of the material is connected without being cut so much that the strength during forging can be maintained. .

[0010]

EXAMPLES Hereinafter, examples embodying the present invention will be described.
This will be described with reference to FIGS. As shown in FIGS. 1 to 3, the rocker arm with roller 1 manufactured by the method of the present embodiment includes a main body 2 and a roller 3. Body 2
Are a base end 4 serving as a tilting center of the rocker arm, a front end 5 for pressing the valve stem 21, a base end 4 and a front end 5
And a pair of side wall portions 7 standing upright on both sides of the base end portion 4, the distal end portion 5, and the through hole 6, which are provided between the through hole 6 and the base.

A spherical recess 8 into which a spherical head 23 of a pivot shaft 22 is fitted is formed on the lower surface of the base end 4. On the lower surface of the distal end portion 5, a pad surface 9 which comes into contact with the end surface of the valve stem 21 and a pair of fork portions 10 which sandwich the outer peripheral surface of the end portion of the valve stem 21 are formed. Roller 3 which receives pressure of cam 24 between both side walls 7 and through hole 6
And the roller 3 is supported by a support shaft 11 passed through the side wall portions 7.
, And is rotatably mounted by a bearing 12.

The rocker arm with roller 1 is manufactured through the following steps. As shown in FIGS. 4 and 5, the thickness of the material 15 is changed from a circular or elliptical material 15 (preferably a shape with little waste) made of, for example, a steel plate , and the spherical recess 8 is formed.
A thick base end portion 4 having a pad surface 9 and a thick end portion 5 having a fork portion 10, and a flat surface continuous between the base end portion 4 and the front end portion 5 and slightly recessed downward. Square middle part 16
And a pair of thin side portions 17 continuous on both sides of the base portion 4, the tip portion 5 and the intermediate portion 16 are cold forged into a developed shape while the flat state of the material 15 is substantially maintained. .

As shown in FIGS. 6 and 7, the peripheral portions of the pair of side portions 17 and unnecessary portions of the material are punched into a required peripheral shape (in the drawings, a mountain shape). As shown in FIG. 8 and FIG. 9, the pair of side portions 17 are bent so as to stand up to form the side walls 7 of the rocker arm. After this bending, as shown in FIG.
6 is punched to form a through hole 6. If the pair of side portions are bent after forming the through hole, distortion occurs around the through hole during the bending process. However, if the method is performed as in the present method, the distortion does not occur. As shown in FIGS. 1 to 3, the roller 3 is disposed between the side wall portions 7 and between the through holes 6, and the roller 3 is rotatably mounted on the support shaft 11 and the bearing 12.

In this embodiment, the space in which the roller 3 is arranged can be formed by bending the side portion 17 and punching the intermediate portion 16 without cutting the mounting hole unlike the conventional forging type. You can do it. For this reason, the number of cut portions is reduced, and the degree of freedom in designing the machining shape is increased, so that the optimal design for reducing the weight is facilitated. Further, since the through hole 6 formed by punching the intermediate portion 16 is shallower than the conventional large and deep mounting hole, the fiber flow at the time of forging the material 15 is connected without being cut so much, and the strength at the time of forging is maintained. be able to.

The present invention is not limited to the configuration of the above-described embodiment. For example, the present invention can be modified and embodied as follows without departing from the spirit of the invention. (1) In addition to steel plates, various shapes and materials can be used as a material for forging. For example, a round bar cut product can be used as a material. (2) After forming the through hole 6 by punching, the following processing may be added. The inner surface of the through hole 6 formed by punching and the side wall 7
Some steps are likely to occur at the boundary with the inner surface of the. Therefore,
For example, it is preferable to iron this boundary and remove the step. Stamping may cause some distortion around it. Therefore, for example, it is preferable to improve the accuracy by coining the spherical concave portion 8, the pad surface 9, the fork portion 10 and the like.

[0016]

As described above in detail, according to the method of manufacturing a rocker arm with a roller of the present invention, the forging process requires
Forging to the required developed shape by changing the thickness of the material
Thus, the degree of freedom and accuracy of the processing shape are increased. Also, a pair of
After bending the side part, punch out the middle part and penetrate
Since the holes are formed, no distortion occurs during bending. Further
In addition, the number of cutting points is reduced, it can be manufactured at low cost, and the strength is high
Also, an effect such as an increase can be obtained.

[Brief description of the drawings]

FIG. 1 is a sectional view taken along line II of FIG. 2, showing a rocker arm with a roller according to an embodiment of the present invention.

FIG. 2 is a plan view of the rocker arm.

FIG. 3 is a left side view of the rocker arm.

FIG. 4 is a plan view of a material after forging.

FIG. 5 is a sectional view taken along line VV of FIG. 4;

FIG. 6 is a plan view after blanking of a material.

FIG. 7 is a sectional view taken along line VII-VII of FIG. 6;

FIG. 8 is a plan view after bending a side wall portion of the material.

FIG. 9 is a sectional view taken along line IX-IX of FIG. 8;

FIG. 10 is a cross-sectional view of the intermediate portion of the material after punching.

FIG. 11 is a front view of a conventional cast or forged type rocker arm with roller.

FIG. 12 is a plan view of the rocker A over arm.

FIG. 13 is a front view of a conventional sheet metal boat type rocker arm.

FIG. 14 is a plan view of the rocker A over arm.

FIG. 15 is a front view of a conventional sheet metal bending type rocker arm with roller.

FIG. 16 is a plan view of the rocker A over arm.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Rocker arm with a roller 2 Main body 3 Roller 4 Base end part 5 End part 6 Through hole 7 Side wall part 15 Material 16 Intermediate part 17 Side part 21 Valve stem 24 Cam

Claims (1)

(57) [Claims] 1. A base end serving as a tilting center of a rocker arm, a front end for pressing a valve stem, an intermediate part continuous between the base end and the front end, and a pair of parts continuous on both sides of the intermediate part. And forging a side portion of the material into a desired developed shape by changing the thickness of the material from the material, and punching the peripheral portions of the pair of side portions into a required peripheral shape. A step of bending the pair of side parts so as to be upright to form both side walls of the rocker arm, and a step of forming a through hole by punching out the intermediate part after the bending step. Arranging a roller which receives the pressure of the cam between the side wall portions and in the through hole, and rotatably mounting the roller on the both side wall portions in a rotatable manner.