JP3438036B2 - Rocker arm - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a center pivot type rocker arm that is tilted by a cam to open and close a valve provided in a cylinder head. In particular, the rocker arm of the present invention has a main part manufactured by sheet metal working.

[0002]

2. Description of the Related Art As a conventional rocker arm made of sheet metal of this type, for example, Japanese Patent Application No. 57-51031 (Japanese Utility Model Application Laid-Open No. 58-58).
No. 152503).

In this conventional rocker arm, a through hole is provided in the middle of the pair of wall portions formed by bending a flat plate in the longitudinal direction, and a cylindrical bush is fitted and fixed in the through hole, and a tilting fulcrum is supported on the bush. The shaft is designed to be inserted. The tilt fulcrum shaft is supported by the cylinder head or the like.

The bush described above is provided with a flange outward in the radial direction at one end in the axial direction, and after the bush is fitted into the through holes of the pair of wall portions, the other end in the axial direction of the bush is provided. It is fixed by being caulked.

[0005]

By the way, in the above-mentioned conventional rocker arm, since the load caused by the tilting motion is received by the through holes of the pair of wall portions, an excessive surface pressure is applied to the through holes of the wall portions. It is supposed to take. Therefore, the wall portion is likely to be deformed with time, and rattling of the rocker arm may occur.

Therefore, an object of the present invention is to improve the support rigidity of the tilt fulcrum shaft in the wall portion of the rocker arm.

[0007]

A rocker arm of the present invention is a center pivot type rocker arm that is tilted by a cam to open and close a valve provided in a cylinder head, and bends a flat plate to face each other substantially in parallel. Then
A pair of wall portions are formed to be spaced apart from each other, the pair of wall portions
Cylindrical bulged portion protruding toward the inner to the respective longitudinal intermediate
Integrally installed , the tilting fulcrum shaft is attached to both the cylindrical bulging parts.
Attached to the free end side of each of the pair of wall portions.
A mounting hole is provided in the
When the abutting rollers are positioned,
Both ends of a support shaft that covers the blade are fitted and fixed, and a valve receiving portion that is brought into contact with the upper end of the valve is provided at a bending fulcrum portion of the pair of wall portions.

[0008]

[0009]

Both ends of the cylindrical member can be fitted and fixed to the cylindrical bulging portions of the pair of wall portions, and the tilting fulcrum shaft can be relatively rotatably inserted into the cylindrical member.

In short, according to the present invention, the wall portion is provided with the tubular bulging portion, and the tilting fulcrum shaft is indirectly attached to the tubular bulging portion via the hollow shaft, or the tilting fulcrum shaft is directly attached. By being attached, the load caused by the tilting motion is received by the tubular bulging portion having a width wider than the wall thickness of the wall portion. For this reason, the surface pressure acting on the wall portion becomes smaller than that in the conventional case, so that the supporting rigidity of the tilt fulcrum shaft in the wall portion is enhanced.

[0012]

DETAILED DESCRIPTION OF THE INVENTION The details of the present invention will be described with reference to the embodiments shown in FIGS.

1 to 3 relate to a first embodiment of the present invention. FIG. 1 is an exploded perspective view of a rocker arm, FIG. 2 is a side view of the rocker arm, and FIG. 3 is (3)-(3) of FIG. ) It is an arrow view of a line cross section. In the figure, 1 is a cam, 2 is a valve, 3
Is a rocker arm.

In the rocker arm 3, a roller 32 as a cam receiving portion on which the cam 1 is in rolling contact with the free ends of a pair of wall portions 31 facing each other in parallel is provided with a plurality of needle rollers 33 and a support shaft 34. Attached, a pair of wall parts 31, 31
A screw shaft 36 as a valve receiving portion with which the upper end of the valve 2 abuts is attached to the connecting portion 35 of the pair of wall portions 3
A tilting fulcrum shaft 38 is attached to an intermediate portion in the longitudinal direction of 1, 31 via a hollow shaft 37, and tilts with the tilting fulcrum shaft 38 in the longitudinal direction as a fulcrum. In addition,
The tilt fulcrum shaft 38 is supported by a cylinder head (not shown) or the like.

Further, in the middle of the pair of wall portions 31, 31 in the longitudinal direction, there are provided inwardly projecting cylindrical swelling portions 39, 39 for mounting the tilting fulcrum shaft, respectively. Both ends of a hollow shaft 37 as a cylindrical member are fitted and fixed to the projecting portions 39, 39. A tilting fulcrum shaft 38 is inserted into the hollow shaft 37 so as to be relatively rotatable. Hollow shaft 37
Is a steel pipe material or a material having a self-lubricating property, such as a copper alloy.

Next, a method of manufacturing the rocker arm 3 will be briefly described.

First, the walls 31, 31 are manufactured. That is, one metal plate is punched into a required shape. At this time, by drawing the required positions on the wall portions 31, 31, a cylindrical bulging portion with a bottom is formed and the bottom portion is punched out, and further, the free end sides of the wall portions 31, 31 are made circular. The mounting holes 40, 40 of the support shaft 34 of the roller 32 are formed by punching. The above-mentioned cylindrical bulging portion becomes the above-mentioned cylindrical bulging portion 39. The processed product is bent into two folds with the center in the longitudinal direction as a fulcrum, and while the bending fulcrum part is curved into a cylindrical shape, the vicinity thereof is brought into close contact with each other and the end side parts are made to face each other substantially in parallel. The close contact portion of this processed product is joined by welding or the like, and a screw groove is formed on the inner surface of the bending fulcrum portion curved in the cylindrical shape. This bending fulcrum portion becomes the above-mentioned connecting portion 35.

Next, the hollow shaft 37 is press-fitted or shrink-fitted into the cylindrical bulging portions 39, 39 of the wall portions 31, 31 to be fixed thereto, and the screw shaft 3 is inserted into the connecting portion 35 from below.
Screw 6 on. The hollow shaft 37 may be fixed by welding, or may be fixed by caulking the shaft end of the hollow shaft 37.

After that, both ends of the support shaft 34, which covers the roller 32 via a plurality of needle rollers 33, are fitted and fixed into the mounting holes 40 at the free ends of the walls 31, 31 by press fitting or shrink fitting. The support shaft 34 may be fixed by welding, or may be fixed by caulking the shaft end of the support shaft 34.

As described above, the rocker arm 3 of this embodiment has the cylindrical bulging portion 3 on the pair of wall portions 31, 31.
9 and 39 are provided, and the hollow shaft 37 is attached to the cylindrical bulging portions 39 and 39, and the tilting fulcrum shaft 38 is inserted into the hollow shaft 37.
It can be received by the cylindrical bulging portions 39, 39 which are wider than the wall portions 31, 31. Therefore, the surface pressure on the wall portions 31, 31 can be made smaller than in the conventional case, and the supporting rigidity of the tilting fulcrum shaft 38 on the wall portions 31, 31 can be increased. This makes it difficult for the cylindrical bulging portions 39, 39 to deform for a long period of time, and prevents the rocker arm 3 from rattling.

The present invention is not limited to the above-described embodiments, but various applications and modifications can be considered.

[0022]

[0023] b Kkaamu 3, in addition to those described above in Example 1, and it can also apply the present invention to constituted as shown in FIG. 6, in short, the present invention as long as center pivot type Can be applied.

The structure of the rocker arm 3 of the second embodiment shown in FIG. 6 will be described. The second embodiment differs from the first embodiment in the shape of the pair of wall portions 31, 31. That is, as shown in FIG. 7, the metal plate is punched out into a substantially U-shape in a plan view. , 39, circular mounting holes 40, 40 on the free end sides of the projecting piece portions A, A, and the screw shaft 3 on the connecting portion B.
The bulging portion 35a for screwing 6 is formed. The two projecting piece portions A, A of this metal plate are bent vertically along the broken lines of their connecting portions B. Thereby, the pair of wall portions 31, 3
1 is formed. Then, the roller 32, the screw shaft 36, and the hollow shaft 37 are mounted in the same manner as in the first embodiment. The second embodiment does not require the joining process between the pair of wall portions 31, 31 as in the first embodiment, and thus has an advantage that the manufacturing cost can be reduced.

(3) The roller 32 can be rotatably supported by sliding contact without supporting the plurality of needle rollers 33 on the support shaft 34. That is, it is possible to fit the roller 32 to the support shaft 34 with a clearance, or to fit it via a slide bearing such as a bush.

(4) In the first and second embodiments, the roller 32 is used as the cam receiving portion and the screw shaft 36 is used as the valve receiving portion.
Although not shown, they may be replaced by a chip-shaped member made of a suitable metal material.

[0027]

According to the present invention, since the load caused by the tilting motion is received by the cylindrical bulging portion having a width wider than the wall thickness of the wall portion, the surface pressure acting on the wall portion is higher than that in the conventional case. Since the size can be reduced, the support rigidity of the tilt fulcrum shaft in the wall can be increased. Therefore, the tubular bulging portion is unlikely to be deformed for a long period of time, and it is possible to prevent rattling of the rocker arm.

As described above, according to the present invention, it is possible to provide a highly reliable rocker arm capable of realizing stable operation for a long period of time.

[Brief description of drawings]

FIG. 1 is an exploded perspective view of a rocker arm according to a first embodiment of the present invention.

FIG. 2 is a side view of the rocker arm according to the first embodiment.

3 is an arrow view of a cross section taken along line (3)-(3) of FIG.

FIG. 4 is a perspective view of a rocker arm according to a second embodiment of the present invention.

[Fig. 5] Fig. 5 is a striking of the rocker arm of the second embodiment before bending the wall portion.
Plane showing punched shape

[Explanation of symbols]

1 cam 2 valves 3 rocker arm 31 wall 35 Connection 36 screw shaft 37 hollow shaft 38 Tilt fulcrum shaft 39 Cylindrical bulge of wall

Continuation of the front page (56) Reference JP-A-63-272903 (JP, A) Actual opening Sho-58-64805 (JP, U) Actual opening Sho-55-36922 (JP, U) Actual opening Sho-59-21003 (JP , U) US Patent 27176083 (US, A) US Patent 5010857 (US, A) (58) Fields investigated (Int.Cl. ⁷ , DB name) F01L 1/18

Claims (2)

(57) [Claims] 1. A center pivot type rocker arm that is tilted by a cam to open and close a valve provided in a cylinder head, wherein a pair of wall portions that bend a flat plate and face each other in substantially parallel, and are separated from each other. is formed, the cylindrical bulged portion protruding toward the inner longitudinally intermediate of each of the pair of wall portions are provided integrally,
A tilting fulcrum shaft is attached to both the cylindrical bulging portions,
A mounting hole is provided on the free end side of each of the pair of wall portions.
A roller that abuts the cam between the pair of wall portions facing each other.
Support shaft with the rollers installed in both mounting holes when positioned
Both ends of the wall are fitted and fixed, and the bending fulcrum parts of the pair of wall parts
Is equipped with a valve receiving part that can be brought into contact with the upper end of the valve.
Rocker arm, characterized by being. 2. A circular shape is formed on each of the cylindrical bulging portions of the pair of wall portions.
Both ends of the cylindrical member are fitted and fixed, and the tilting support is attached to this cylindrical member.
The rocker arm according to claim 1, wherein the point axis is relatively rotatably inserted therethrough.