JPS59225844A - Production of plunger for valve lash adjuster - Google Patents

Abstract

PURPOSE:To eliminate hindrance in the operation of a plunger and to permit easy working in press forming of the spherical face at the end of the plunger by reducing the wall thickness corresponding to the spherical face of a blank material and determining the step part thereof and the bottom end of the spherical face upper by a specific size than the virtual center of the spherical face. CONSTITUTION:The inside diameter 23 of the part corresponding to the spherical face of a blank material is made to about 68-85% of the outside diameter 24 and the position 28 in the stepped part of the inside diameter is made to about 63-92% of the distance R up to the virtual central position 21 of the spherical face in the shape of the blank material prior to press forming of the spherical shape at the tip of a plunger for a valve lash adjuster. The position 22 of the part corresponding to the bottom end of the spherical face is also made upper than the position 21. If the spherical face is press-formed from the blank material having such shape, the plastic working of the spherical face is made easy and the deformation of the spherical face during use is decreased. Since there is no straight line part at the bottom end of the spherical face, the fitting of the spherical face is smooth. The spherical face may be reinforced by ribbing internally and the outside surface may be grooved for easier working.

Description

[Detailed description of the invention] The present invention is a plunger for a valve lash adjuster. The present invention relates to a method for manufacturing a camera.

In general, internal combustion engine valve gears, mainly intake and exhaust valves, rocker arms, etc., expand thermally due to the temperature during operation.
Due to the dimensional changes caused by this, a valve gap is provided to prevent the valve from becoming unable to close reliably during operation. However, due to temperature changes and wear of various parts over time, the valve gap changes, causing problems such as noise generation and poor airtightness between the valve and the valve seat when the valve is closed. The valve lash adjuster is used to eliminate this point.
It is installed at the pivot part of the rocker arm or rocker shaft, eliminates the need for adjustment to the tappet 1, maintains a constant valve gap, makes valve timing accurate, improves engine performance, and further reduces tappet tapping noise. This provides advantages such as increased durability of the valve train by absorbing shock.

The plunger of a conventionally used valve lash adjuster was manufactured by the process shown in FIG. 1, and was molded into the shape shown in FIG.

That is, a hole 6 is provided in the outer diameter groove 4 of a bottomed tube 3 having a bottom 2 on the opposite side of the end 1, and a concave spherical mold 7 is used to form the bottomed tube 3.
was pressurized in the axial direction, and the end portion 1 was formed into a spherical molded portion 9 having a hole 8 of a required size at the tip. Reference numeral 5 indicates a neck portion having a groove-shaped outer shape.

According to this conventional method, the end 1 of the bottomed tube 3 gradually becomes thicker as it approaches the hole 8 of the spherical molding part 9 of the concave spherical mold 7, and the hole 8 is plastically deformed to the required size. is completed early, the deformation resistance gradually increases, and the flow of the meat is not continuous, resulting in poor formability, and as shown in Fig. 4, the spherical molded part 9
The straight portion 10 remains and the pivot portion P is locked, and the hole 6 is slightly deformed due to strain. Furthermore, as shown in FIG.
Since this remains considerably large, there is a problem in that when the pivot portion P is tilted at an angle α as shown in FIG. 4, it interferes with the end portion T, causing problems in use. In addition, the concave spherical surface portion of the concave spherical mold 7 wears out quickly, causing problems in terms of life.

The present invention improves moldability, which is a problem with the conventional method described above, thereby reducing molding pressure, reducing the load on manufacturing machinery, and improving mold life, thereby reducing costs. In addition, the purpose is to manufacture a new valve lash adjuster plunger that maintains the strength of the molded part and solves problems in use.

The features of the method for manufacturing a plunger for a valve lash adjuster according to the present invention are explained below with reference to the attached FIGS. 5 to 8. In the basic cross-sectional view on the left side of FIG. 5, reference numeral 21 is the virtual center of the sphere and is located at a distance R from the tip, where R is the radius of the concave spherical mold 7.

22 indicates a spherical end, 23 indicates an inner diameter of the end, and 24 indicates an outer diameter of the end. 25 is a C chamfer, 26 is a forming base point located at a distance of R from the tip, 27 is a small curved portion, and 28 is an inner diameter stepped position. Further, 29 is the ball R dimension.

Therefore, the characteristics of the method of the present invention are listed as follows.

(1) On the inner surface of the end side of the aforementioned bottomed tube body, as shown in FIG.
Formability can be improved by providing a stepped portion 7 and making the wall thickness slightly thinner to reduce deformation resistance.

(2) In order to improve the flow of the meat, a slight C chamfer 25 is provided on the inner surface of the end side to delay the time for the hole to reach the required size, thereby reducing deformation resistance and improving formability. I can do it.

(3) By providing the inner diameter stepped position 28 slightly above the virtual sphere center position 21, the strength of the forming base point 26 can be increased and the amount of bulge and expansion can be minimized.

(4) By providing the spherical end portion 22 slightly above the spherical center virtual position 21, the aforementioned straight portion will not remain after molding.

(5) It is appropriate that the end inner diameter 23 is 68 to 85% of the end outer diameter 24, and the inner diameter stepped position 28 is 63 to 92% R from the tip, but these dimensions and the C chamfer 25 are small. Music section 27
The dimensions are determined experimentally depending on the required strength.

(6) Depending on the required strength, the inner diameter of the end is 23 mm as shown in Figure 6.
By providing one or more small grooves in the ribs 31, the ribs 31 can achieve the effect of -F in the strength direction, thereby improving the formability without reducing the strength.

(7) Depending on the required strength, formability can be improved by providing one or more small grooves 32 on the outer diameter 24 of the end portion as shown in FIGS. 7 and 8.

According to the method of the present invention, the following effects are produced.

(1) Reducing the load on the manufacturing machine In the case of the present invention, since the inner diameter is stepped, the moldability is improved and the molding pressure is 58 to 62% of the conventional pressure, reducing the load on the manufacturing machine.

(2) Improving the mold life of the mold In the case of the present invention, the inner diameter is stepped and the wall thickness can be made thinner than the conventional one, reducing the burden on the mold and improving the lifespan by four times compared to the conventional one. I can do things.

(3) Weight reduction In the case of the present invention, since the inner diameter is stepped, the weight can be reduced by an amount equivalent to the parts 3 and 8 in Fig. 5, and the weight can be reduced in proportion to the strength. .

It should be noted that the present invention is not limited to the above-mentioned content, and it is clear that it can be applied to the manufacture of products other than plungers for valve brush core adjusters.

[Brief explanation of the drawing]

FIG. 1 is an explanatory sectional view showing the steps of the conventional method, FIG. 2 is a sectional view of a product made by the conventional method, and FIGS. 3 and 4 are partially enlarged sectional views of the product made by the conventional method. FIGS. 5 and 8 are cross-sectional views showing a construction method and a product according to an embodiment of the method of the present invention. The symbols in the drawings indicate the following members, respectively. 1: End portion 2: Bottom portion 3: Bottomed tube body 4: Outer diameter groove portion 5: Outer groove shaped neck portion
6: Hole 7 Concave spherical molded part 8: Hole 9: Spherical molded part 10: Straight part 11: Expansion amount 7- 21: Virtual sphere center position 22: Spherical outer diameter 23:
End inner diameter 24: End outer diameter 25: C chamfer
26: Forming base point 27: Small curved part 28: Inner diameter stepped position 29: Ball R dimension 30:
Groove 31: Rib 32: Groove Patent applicant: Nippon Valve Co., Ltd. 8-

Claims (1)

[Scope of Claims] 1. The tip of a bottomed tube consisting of a cylindrical shape with a groove on the outer circumferential surface and a central hole communicating with a dish-shaped bottom surface is pressed into a concave spherical mold with radius R. In processing the plunger to form a spherical molded part with holes, the shape of the tip part that is a distance of R from the tip of the bottomed tube body to the distance wi (the imaginary position of the spherical center) is determined by (1) the imaginary position of the spherical center; At a position closer to the tip, the inner peripheral surface of the tip is made into a stepped shape larger than the inner diameter of the central hole, making the tip thinner, and the stepped portion is provided with a small curved portion, and the tip of the inner peripheral surface is provided with a chamfered portion. (2) closer to the tip than the imaginary position of the center of the sphere, and (1)
A valve lash adjuster characterized in that the groove on the outer peripheral surface starts at a position farther from the tip than the position of the head.
- ＾Method of manufacturing a plunger for A-so. 2. Claim 1, characterized in that the inner diameter of the tip is 68% to 85% of the outer diameter, and the stepped portion of item (1) is located 63% to 92% R from the tip. A method for manufacturing a plunger for a valve lash adjuster as described in 2. 3. Claim 1 characterized in that one or more small grooves are provided on the inner circumferential surface of the tip of the above item (1).
A method for manufacturing a plunger for a valve lash adjuster as described in 2. 4. Claim 1 characterized in that one or more small grooves are provided on the outer circumferential surface of the tip of the above item (2).
A method for manufacturing a plunger for a valve lash adjuster as described in 2. 5. The method of manufacturing a plunger for a valve lash adjuster according to claim 1, characterized in that a small groove is installed between the outer circumferential surface of the tip end and the groove according to item (2).