JPH10180398A - Method for forging circular-cylinderlike housing having internal circumference flange - Google Patents

Abstract

PROBLEM TO BE SOLVED: To form the internal diameter of a internal circumference flange in the high dimensional precision and to make the yield of the material excellent by inserting a restraint part of an intermediate product in the internal circumference of an intermediate flange of an intermediate forming product and pressing the end part of the intermediate forming product. SOLUTION: An intermediate product is put in a mold engraved space 83 of a lower die 81, and an upper die 61 is lowered. A 1st opening part 16 of the intermediate product is pressed and deformed to the external circumference side. Further, an intermediate flange is pressed between a step like part 64 and a mandrel 84, and the internal diameter end of the intermediate flange is made in contact with a restraint part 63. Further, a forming punch 62 is lowered, the external circumference of the 1st opening part 16 is formed in a circumference like projecting convex end part copying the internal circumference face of a die 82, and the internal circumference of the 1st opening part 16 and the internal circumference of the intermediate flange are formed in a prescribed housing 31 internal circumference shape. Therefore, the forging of the circular-cylinder like housing 31 having the internal circumference flange 32 is completed.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for forging a cylindrical housing having an inner peripheral flange, which is a constituent member such as a ball joint used for a suspension system and a steering system of an automobile.

[0002]

2. Description of the Related Art Conventionally, a cylindrical housing having an inner peripheral flange which is a constituent member of a ball joint has been formed by a cold forging process as shown in FIG. That is, a columnar material 1 having substantially the same volume as the desired volume of the housing 131.
1 (FIG. 4A) is extruded to form a cylindrical wall 113 having a first opening 116 at one end and a second opening 117 at the other end, and an inner periphery at the first opening 116 side. Wall 113
H comprising a bottom 112 which divides the inner peripheral space of the
A preform 111 (FIG. 4A) is formed. Next, near the center of the bottom 112 of the preform 111 is punched,
Intermediate molded article 121 provided with intermediate flange 122 on the inner periphery
((C) in FIG. 4) is formed, and then the intermediate molded product 121 is formed.
The first opening 116 is pressed to form a convex end 135 projecting to the outer peripheral side to form the housing 131 (FIG. 4D).

[0003]

According to the cold forging method as described above, when the first opening 116 of the intermediate molded product 121 is pressed to form the convex end 135 protruding to the outer peripheral side, it is possible to obtain a desired shape. In order to obtain the shape of the convex end portion 135, the excess thickness flows to the inner peripheral flange 132. As a result, the convex end 135 is formed with high accuracy, but the inner peripheral flange 13 is formed.
2. Particularly, it is difficult to shape the inner peripheral end due to the flow, and the inner diameter sometimes varies.
In addition, extra thickness is taken on the inner peripheral end side of the inner peripheral flange 132, and thereafter, excess material is cut off by cutting, but the yield may be reduced because the extra extra thickness is cut off. .

Accordingly, an object of the present invention is to solve the problems described above and to provide a method for forging a cylindrical housing having an inner peripheral flange with high dimensional accuracy of the housing and good yield.

[0005]

The present invention is as follows.

A first step of cold forging a material having substantially the same volume as the desired housing volume to form a cup-shaped preform having a bottom, and punching out the vicinity of the center of the bottom of the preform to obtain a desired shape. A second step of forming an intermediate molded article provided with an intermediate flange having an inner diameter larger than the inner peripheral flange inner diameter to be provided, and a restraining portion having an outer diameter equal to the inner peripheral flange inner diameter of a desired housing is provided at the tip end A third step of inserting the constrained portion of the formed punch into the inner periphery of the intermediate flange of the intermediate molded product, pressing the end of the intermediate molded product, and molding the desired convex end and the inner peripheral flange.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to FIGS.

FIG. 1D shows a cylindrical housing 31 formed by the forging method of the present invention, which has a first opening 16 at one end and a second opening 17 at the other end. An inner peripheral flange 32 protruding toward the center is formed on the inner periphery of the opening 16, and a convex end 35 protruding circumferentially is formed on the outer periphery of the first opening 16.

FIG. 1 shows a forging method of the housing 31.
It will be described based on.

First, a columnar material 1 (FIG. 1A) having substantially the same volume as the desired housing 31 is extruded, and a first opening 16 is provided at one end and a second opening is provided at the other end. 1
7 and a bottom part 12 that divides the inner peripheral space of the wall 13 into two parts on the inner periphery of the first opening 16 side (see FIG. B) is formed. Next, an intermediate molded product 21 having a center near the center of the bottom portion 12 of the preformed product 11 and an intermediate flange 22 provided on the inner periphery thereof is provided.
((C) of FIG. 1) is formed, and then, the first opening 16 of the intermediate molded product 21 is pressed, and the convex end 3 protruding to the outer peripheral side is formed.
5, and the inner peripheral flange 32 is protruded inward to form a desired housing 31 (FIG. 1D).

A process for forming the housing 31 from the intermediate molded product 21 will be described with reference to FIG.

Reference numeral 51 denotes a forging device, which comprises an upper die 61 and a lower die 81.

The upper die 61 has a forming punch 62 disposed along the axis thereof. The tip of the forming punch 62 has a constraint portion 63 having an outer diameter equal to the inner diameter of the desired inner peripheral flange 32 of the housing 31. And a stepped portion 64 which is continuous from the restraining portion 63 and has the same outer peripheral shape as the inner peripheral shape of the first opening portion 16. A ring-shaped punch guide 65 is provided on the outer peripheral side of the forming punch 62, and a spacer 67 is further provided on the outer peripheral side of the punch guide 65. The punch guide 65 and the spacer 67 are assembled together by an upper fixture 66.

The lower die 81 has a die 8 provided with a through hole 92 having the same shape as the outer shape of the housing 31 in the upper portion of the inner circumference.
2, a mandrel 84 facing the forming punch 62 and extending along the axis is disposed in the through hole 92. The tip of the mandrel 84 is connected to the second opening 17 of the housing 31.
A knockout ring 85 having the same outer peripheral shape as the inner peripheral shape and capable of moving up and down in the vertical direction is disposed between the mandrel 84 and the die 82. The upper surface of the knockout ring 85, the inner peripheral surface of the die 82, and the outer peripheral surface of the mandrel 84 define a stamping space 83. A cylindrical base material 86 is provided below the die 82, and a backup ring 87 is provided on the outer peripheral side of the cylindrical base material 86. And the die 82 is fixed on the cylindrical substrate 86.

When the housing 31 is formed from the intermediate molded product 21 by the forging device 51, as shown in the left half of FIG.
The intermediate molded product 21 is put into the engraving space 83 of the lower die 81 in a state where the upper die 61 is on standby above, and then the upper die 61 is lowered. The molding state at this time will be described with reference to FIG. 3. First, as shown in FIG. 3A, a restraining portion of a forming punch 62 having the same outer diameter r as the inner diameter of the inner peripheral flange 32 of the desired housing 31. 63 to the desired housing 3
While being lowered and inserted into the inner space of the intermediate flange 22 having an inner diameter R larger than the inner diameter of the inner peripheral flange 32,
The first opening 16 of the intermediate molded product 21 is pressed and deformed to the outer peripheral side (FIG. 3A). Then, the forming punch 62 further descends, the outer peripheral end of the first opening 16 contacts the inner peripheral surface of the die 82, and the intermediate flange 22 is pressed between the stepped portion 64 and the mandrel 84 so that the intermediate flange 22 is pressed. The inner diameter end of the abutment comes into contact with the restricting portion 63 ((c) in FIG. 3). Thereafter, the forming punch 62 further descends, and the outer periphery of the first opening 16 is formed into a convex end 35 which protrudes circumferentially following the inner peripheral surface of the die 82, and the inner periphery of the first opening 16 and the intermediate flange are formed. The inner circumference 22 is formed into a predetermined housing 31 inner circumference shape ((D) in FIG. 3 and the left half part in FIG. 2), and the inner circumference flange 32 is formed.
Forging of the cylindrical housing 31 having the above is completed.

Accordingly, the cylindrical housing 31 having the inner peripheral flange 32 formed by the forging method is molded while the inner periphery of the inner peripheral flange 32 is regulated by the restricting portion 63, so that the inner diameter is highly accurate. Can be molded.

The inner peripheral flange 3 of the housing 31
2 is finished by forging, but the underfill is apt to be formed at the lower end of the inner circumference.
The overall length of 3 may be slightly shortened so that the extra thickness swells at the lower end of the inner peripheral flange 32, and then the extra thickness may be cut off. As a result, the yield is reduced, but the yield is still sufficiently good as compared with the related art.

[0018]

As described above, according to the present invention, a first step of cold forging a material having substantially the same volume as a desired housing volume to form a cup-shaped preform having a bottom portion is provided. A second step of punching the vicinity of the center of the bottom of the preform and forming an intermediate molded product provided with an intermediate flange having an inner diameter larger than the desired inner peripheral flange inner diameter, and the same as the desired inner peripheral flange inner diameter of the housing. Inserting the restraining portion of the forming punch provided at the tip with a restraining portion having an outer diameter of the diameter into the inner periphery of the intermediate flange of the intermediate molded product and pressing the end of the intermediate molded product, the desired convex end Since the method includes the third step of forming the peripheral flange, the inner diameter of the housing, particularly the inner peripheral flange, can be formed with high dimensional accuracy, and the yield of the material is good.

[Brief description of the drawings]

FIG. 1 is a cross-sectional plan view illustrating a forging method of a cylindrical housing having an inner peripheral flange according to an embodiment of the present invention.

FIG. 2 illustrates a forging process of forming a cylindrical housing having an inner peripheral flange from an intermediate molded product according to an embodiment of the present invention;
The left half is a partial sectional plan view showing a state before molding, and the right half is a partial sectional plan view showing a state after molding.

FIG. 3 is an enlarged view of part A of FIG. 2 showing a state in which a cylindrical housing having an inner peripheral flange is molded from an intermediate molded product (a).
It is a fragmentary sectional plan view explained in detail in (d).

FIG. 4 is a cross-sectional plan view illustrating a forging method of a cylindrical housing having an inner peripheral flange according to a conventional example.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 base material 11 preformed product 12 bottom 21 intermediate molded product 22 intermediate flange 31 housing 32 inner peripheral flange 35 convex end 62 forming punch 63 restraining portion R (intermediate flange) inner diameter r (restricting portion) outer diameter

Claims (1)

[Claims] A material (1) having substantially the same volume as a desired housing (31) is subjected to cold forging, and a bottom (1) is formed.
A first step of forming a cup-shaped preform (11) having 2), and punching the vicinity of the center of the bottom (12) of the preform (11) to have a larger diameter than the desired inner peripheral flange (32) inner diameter A second step of forming an intermediate molded product (21) provided with an intermediate flange (22) having an inner diameter (R), and an outer diameter (the same diameter as the inner diameter of an inner peripheral flange (32) of a desired housing (31)). r) of the forming punch (62) provided at the tip thereof with the restraining portion (63), the restraining portion (63) is inserted into the inner periphery of the intermediate flange (22) of the intermediate molded product (21) and the intermediate molded product (21) is inserted. ) To form a desired convex end (35) and an inner peripheral flange (32). 3. A method for forging a cylindrical housing having an inner peripheral flange. .