JPH06173621A - Direct hitting type valve lifter and manufacture thereof - Google Patents

Abstract

PURPOSE:To manufacture a direct hitting type valve lifter efficiently at low cost so that sufficient strength can be secured functionally in spite of being lighter than usual. CONSTITUTION:Cold forging work is carried out on a cylindrical side wall part 2 and a disk shape end wall part 3, and a body 4 is formed. Wall thickness of the side wall part 2 can be made thinner than usual. While roating the end wall part 3 by sandwiching it between core metal 11 and a presser shaft 12, a roller jig 14 is pushed against an outer peripheral surface of the side wall part 2, and spinning work is carried out. Two end round disk shape projecting parts 16 formed in the middle of the roller jig 14 form annular curved parts 8 in a middle part of the side wall part 2, and a conical projecting part 17 formed in an end part of the roller jig 14 forms a contraction part 9 in an opening end of the side wall part 2. Afterwards, grinding work is carried out on the outer peripheral surface of the side wall part 2, and it is finished smoothly. Since this side wall part 2 has high rigidity structurally, a material fiber flow is continued even after the work.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a direct drive valve lifter (hereinafter simply referred to as a valve lifter) used in a valve operating mechanism of an internal combustion engine and a manufacturing method thereof.

[0002]

2. Description of the Related Art As shown in FIG. 5, a conventional general valve lifter 50 is provided with a body 54 formed by forging a cylindrical side wall portion 52 and a disc-shaped end wall portion 53. Part 5
The shim 56 is fitted in the recess 55 formed on the upper surface of the No. 3. Even with a valve lifter having such a simple structure, weight reduction is required in order to reduce the inertial mass of the valve mechanism in response to the recent high performance of internal combustion engines. Therefore, the applicant previously proposed a valve lifter 51 that is lightened by cutting a plurality of annular grooves 57 on the inner peripheral surface of the side wall portion 52 to reduce the thickness as shown in FIG. 6 ( JP-A-63-16107).

[0003]

However, the side wall portion 52 is only partially reduced in thickness at the annular groove 57.
There was room for further weight reduction. Further, when the annular groove 57 is cut, the fiber flow of the material of the side wall portion 52 is cut off, so that the strength may be deteriorated in terms of material. Further, there is a problem that the cutting process requires a high processing cost, and further, since the cutting process is the groove processing of the inner peripheral surface, the chip discharging property is poor and the work efficiency cannot be improved.

An object of the present invention is to solve the above problems and to secure a sufficient strength in terms of the function of a valve lifter, and to reduce the thickness of the side wall portion as a whole by reducing the thickness of the side wall portion as compared with the prior art. Another object of the present invention is to provide a valve lifter that can retain the lubricating oil on the outer peripheral surface of the side wall portion and reduce wear of the side wall portion and the cylinder head.

Another object of the present invention is to provide a method for efficiently manufacturing the valve lifter as described above at low cost.

[0006]

In order to achieve the above object, the valve lifter of the present invention is provided with at least one annular curved portion formed in a middle portion of a side wall portion, the middle portion being curved inward. The aperture end is formed at the opening end of the side wall portion by bending the opening end inward.

Further, in the method for manufacturing a valve lifter according to the present invention, at least one annular curved portion is formed by bending an intermediate portion of the cylindrical side wall portion inward by spinning or rolling to form at least one annular curved portion. The opening end is curved by spinning, rolling, or pressing to form an aperture portion.

[0008]

According to the valve lifter of the present invention, the annular curved portion and the narrowed portion formed on the side wall portion structurally enhance the rigidity of the valve lifter. Further, since the side wall of each of the annular curved portion and the throttle portion is curved, the fiber flow of the material is continuous, and there is no fear that the strength of the material will deteriorate.
Therefore, it is possible to secure sufficient strength for the function of the valve lifter even if the wall thickness of the entire sidewall portion is made thinner than that of the conventional one to reduce the weight. Further, when the valve lifter is assembled in the guide hole of the cylinder head, the mouth throttle portion acts as a guide portion when it is inserted into the guide hole. Further, when the valve lifter is used, the annular curved portion holds the lubricating oil, so that the wear of the side wall portion and the guide hole is reduced.

According to the method of manufacturing the valve lifter of the present invention, the annular curved portion is formed by spinning or rolling, and the narrowed portion is formed by spinning, rolling or pressing. Therefore, the work efficiency is high and the material yield is good.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A manufacturing method of an embodiment embodying the present invention will be described below with reference to FIGS. As shown in FIG. 1, the valve lifter 1 manufactured by the method of this embodiment is
An inverted cup-shaped body including a bellows-shaped side wall portion 2 slidably inserted in a guide hole 21 formed in a cylinder head, and a disc-shaped end wall portion 3 closing an upper end of the side wall portion 2. It is equipped with 4.

Two annular curved portions 8 are formed in the middle of the side wall 2 so that the middle is curved inward.
At the opening end of the mouth stop portion 9 which is curved inward.
Are formed. A valve stem abutting portion 5 for pushing the upper end of the valve stem 22 is provided at the center of the lower surface of the end wall portion 3, and a circular recess 6 is provided at the upper surface of the end wall portion 3. A disc-shaped shim 7 made of a wear-resistant material is slidably fitted in the recess 6 so as to receive a sliding contact with the cam 23.

The valve lifter 1 is manufactured through the following steps. As shown in FIG. 2, a cylindrical side wall portion 2 and a valve stem contact portion 5 are formed from a rod-shaped or coil-shaped material (not shown).
And the end wall portion 3 having the recess 6 are cold forged to form the body 4. At this time, the wall thickness of the side wall portion 2 is made thinner than before, and the opening end of the side wall portion 2 is press-cut or cut at the position of line A after the forging process. Also. The recess 6 is formed shallower than that at the time of completion.

As shown in FIG. 3, the end wall portion 3 of the body 4 is sandwiched between the core metal 11 from below and the pressing shaft 12 from above. The outer diameter of the core metal 11 is to be removed after processing so that the side wall portion 2
It is designed to be smaller than the inner diameter by about 0.5 mm, and two annular grooves 13 and a conical surface 19 are formed on the outer periphery thereof with a space. Then, while rotating the body 4 together with the core metal 11 and the pressing shaft 12 by the rotating mechanism (not shown),
The roller jig 14 is pressed against the outer peripheral surface of the side wall portion 2 by the pressing tool 15 to perform the spinning process.

The roller jig 14 is rotatably attached to the pressing member 15 and rotates together with the body 4 during processing. In the middle of the roller jig 14, there are two rounded disc-shaped convex portions 1
6 are formed at intervals, and conical protrusions 17 and 18 are formed at both ends of the roller jig 14. The rounded circular disk-shaped convex portion 16 cooperates with the annular groove 13 to bend an intermediate portion of the side wall portion 2 inward, thereby forming two annular curved portions 8 in the intermediate portion. The conical convex portion 17 cooperates with the conical surface 19 to curve the opening end of the side wall portion 2 inwardly, thereby forming the mouth narrowing portion 9 at the opening end. Conical convex portion 18
Chamfers the upper end of the side wall portion 2.

As shown in FIG. 4, the recess 6 of the end wall portion 3 is formed.
Is cut to the B line position, and the upper end of the side wall portion 2 is cut to the C line position. Further, the outer peripheral surface of the side wall portion 2 is heat-treated and then ground as shown by the line D to finish smoothly.

In the present embodiment, the forged cylindrical side wall portion 2 is secondarily processed into a bellows having a structurally high rigidity, and the secondary processing is performed by spinning so that the fiber flow of the material is continuous. Therefore, even if the wall thickness of the side wall portion 2 is made thinner than that of the conventional one to reduce the weight, it is possible to secure sufficient strength for the function of the valve lifter 1. Also,
Since the spinning process has a high work efficiency and a high material yield, the valve lifter 1 can be efficiently manufactured at low cost. Furthermore, when using the valve lifter 1,
Since the lubricating oil is held in the annular curved portion 8 of the side wall 2 that slides in the guide hole 21, the wear resistance of the side wall 2 is also improved.

The present invention is not limited to the configuration of the above-described embodiment, but may be embodied with modifications within the scope not departing from the spirit of the invention, for example, as follows. (1) The number of annular curved portions 8 should be one or three or more. (2) Form the annular curved portion 8 by rolling. (3) Forming the narrowed portion 9 by rolling or pressing.

[0018]

As described above in detail, according to the valve lifter of the present invention, it is possible to reduce the weight of the side wall portion by making the thickness of the entire side wall thinner than the conventional one while ensuring a sufficient strength in terms of function. Further, it is possible to reduce the wear of the side wall and the cylinder head by holding the lubricating oil on the outer peripheral surface of the side wall.

Further, according to the method of manufacturing the valve lifter of the present invention, the valve lifter having the above effects can be efficiently manufactured at low cost.

[Brief description of drawings]

FIG. 1 is a partially cutaway front view of a valve lifter manufactured by a method according to an embodiment of the present invention.

FIG. 2 is a partially cutaway front view of the forged body.

FIG. 3 is a sectional view showing a body spinning method.

FIG. 4 is a partially cutaway front view showing a body finishing method.

FIG. 5 is a partially cutaway front view of a conventional valve lifter.

FIG. 6 is a partially cutaway front view of a conventional improved valve lifter.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Valve lifter 2 Side wall part 8 Annular curved part 9 Narrowing part 11 Core metal 14 Roller jig

Claims (2)

[Claims] 1. A mouthpiece in which at least one annular curved portion is formed at an intermediate portion of the side wall portion, the intermediate portion being curved inward, and the opening end is curved inward at an opening end of the side wall portion. Direct hit type valve lifter with parts. 2. An intermediate portion of a cylindrical side wall portion is curved inward by spinning or rolling to form at least one annular curved portion, and an opening end of the side wall portion is subjected to spinning or rolling. Alternatively, it is a method of manufacturing a direct hitting valve lifter, which is formed by curving inward by press working to form a narrowed portion.