JP2733640B2 - Hollow shaft recess forming method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a hollow shaft forming method for forming a concave portion for fitting a check ball in a longitudinal portion of a metal hollow shaft.

[0002]

2. Description of the Related Art Conventionally, as shown in FIGS.
A hollow shaft 1 made of metal having a predetermined length is provided.
A part in the longitudinal direction of the hollow shaft 1 is pressed in the axial direction by a punch 2 having a plurality of pressing projections 2a in parallel, and three concave portions 3 are formed in a part in the longitudinal direction. was there.

[0003]

In the above prior art, since the rigidity of the hollow shaft 1 is low, between the concave portions 3 which do not contact the pressing projections 2a of the punch 2, that is, the peak portions 4 are formed.
However, there was a drawback that "shape" occurred and molding could not be performed with high precision. SUMMARY OF THE INVENTION An object of the present invention is to provide a novel hollow shaft recess forming method which has solved the above-mentioned disadvantages.

[0004]

Means for Solving the Problems The present invention is configured as follows to achieve the above object. That is, a pair of first metal cores having a first inclined surface formed to be inclined radially outward toward the opposite axis end at opposing shaft ends are provided, and the first cores are arranged such that the first slopes face each other. Gold is fitted into a hollow shaft made of metal, and the wall of the hollow shaft facing each first slope is compressed in the axial direction by a V-shaped first punch to form a first concave portion to form a primary hollow shaft. A second cored bar formed at the shaft end by forming a flat portion parallel to the axis and a second slope inclined radially outward from the base of the flat portion toward the opposite shaft end; The two-core metal and one of the first metal cores are fitted in the primary hollow shaft with the second slope and the first slope facing each other, and a V-shaped shape-retaining punch is fitted in the first recess. After that, the wall of the primary hollow shaft adjacent to the first recess in the axial direction and facing the second slope is axially fixed by the V-shaped second punch. It is obtained by the structure forming the second recess is compressed in the direction. In addition, the second core and one of the first cores are fitted into the primary hollow shaft with their respective second slopes and first slopes facing each other, and a second slope and the one of the first cores are fitted together. The first inclined surface of the one-core metal is separated from the first concave portion on both sides in the axial direction, a V-shaped shape-retaining punch is fitted into the first concave portion, and then the second inclined surface and the one of the first cores are fitted. The wall of the primary hollow shaft facing the first slope of gold is a V-shaped second
Compressed in the axial direction by the punch and the third punch,
In this configuration, the concave portion and the third concave portion are formed.

[0005]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described below with reference to the drawings. In the drawings, FIG. 1 is a cross-sectional view of a main part before forming in a first step according to the present invention, FIG. 2 is a cross-sectional view of a main part after forming in a first step according to the present invention, and FIG. FIG. 4 is a cross-sectional view of a main part after molding in the second step, and FIG.
FIG. 5 is a sectional view taken along line VV of FIG. 4. In FIG. 1, reference numeral 5 denotes a hollow shaft obtained by cutting a metal pipe material, for example, an STKM material into a predetermined size.
The metal cores 6 and 7 are fitted so as to face each other from left and right. Each of the first
The cored bars 6 and 7 have the shaft ends 6a and 7a facing each other with a large diameter and are closely fitted in the hollow shaft 5, and the shaft ends 6a and 7
a first slopes 6b, 7b which are separated from each other and which are inclined upward, are formed above the first slopes 6b, 7b.
Thereby, a space 8 having a triangular shape in a side view is formed in the hollow shaft 5 above the abutting portion of each of the first metal cores 6 and 7.

A first punch 9 is disposed above the space 8. The first punch 9 is provided with the first slope 6
V-shaped pressing projections 9a corresponding to b and 7b are formed. Then, the first punch 9 is moved downward to
As shown in the figure, the wall of the hollow shaft 5 facing the space 8 is compressed and deformed in the axial direction (downward) along each of the first slopes 6b, 7b to form the first concave portion 5a, and the primary hollow shaft B is formed. Get.

Next, as shown in FIG. 3, a second core 10 is fitted to the left portion of the primary hollow shaft B, and a first core 7 is fitted to the right portion of the primary hollow shaft B. Match both. The second core 10 has a right end portion, that is, a shaft end portion 10a having a large diameter, and is fitted closely to a left portion in the primary hollow shaft B, and a primary hollow shaft is provided at an upper right portion of the shaft end portion 10a. A flat portion 10b parallel to the axis of B and a second inclined surface 10c inclined upward from the left end (base portion) of the flat portion 10b toward the left (in the direction opposite to the axial end). The second inclined surface 10c of the second metal core 10 and the first inclined surface 7b of the first metal core 7 correspond to the first concave portion 5 of the primary hollow shaft B.
The space portions 11 and 12 are formed on both left and right sides of the first concave portion 5a.

The first recess 5a and the space 1
Above 1 and 12, the shape-retaining punch 13, the second punch 14,
The third punch 15 is arranged. The lower part of the shape-retaining punch 13 is formed in a V-shape corresponding to the first concave portion 5a, and is urged by a spring 16 to project below the second punch 14 and the third punch 15; The lower part of the three punch 15 is formed in a V-shape having substantially the same shape as the pressing projection 9a of the first punch 9 described above. Then, as shown in FIG. 3, after the shape retaining punch 13 is fitted into the first concave portion 5a,
The punch 14 and the third punch 15 are moved downward to compress and deform the wall of the primary hollow shaft B facing the spaces 11 and 12 in the axial direction (downward), as shown in FIG. A second concave portion 5b and a third concave portion 5c having the same shape are formed on both the left and right sides of the product A to obtain a product A.

FIGS. 6 and 7 show another embodiment. As shown in FIG. 6, the second core 10 ′ is fitted to the right part in the primary hollow shaft B, and the other first metal core 6 is fitted to the left part in the primary hollow shaft B, as shown in FIG. Match both. The second metal core 10 ′ has a left end, that is, a shaft end 1.
0a 'is made larger in diameter, and is fitted closely to the right portion in the primary hollow shaft B. A flat portion 10b' parallel to the axis of the primary hollow shaft B is formed on the upper left portion of the shaft end 10a '. A second inclined surface 10c 'is formed which inclines upward from the right end (base portion) of the portion 10b' toward the right side (the opposite axial end direction). The first inclined surface 6b of the first metal core 6 is brought into contact with the left side of the first concave portion 5a of the primary hollow shaft B, and the second inclined surface 10c 'of the second metal core 10' is rightward with respect to the first concave portion 5a. In the space 12 'on the right side of the first recess 5a.
To form

The first recess 5a and the space 1
The shape retaining punch 13 and the third punch 15 are arranged above 2 'in the same manner as described above. And, as shown in FIG.
After the shape-retaining punch 13 is fitted into the first recess 5a, the third punch 15 is moved downward to compress and deform the wall of the primary hollow shaft B facing the space 12 'in the axial direction (downward). Then, as shown in FIG. 7, a second concave portion 5b ′ having the same shape as the first concave portion 5a is formed on the right side of the first concave portion 5a to obtain a product A ′.

According to the above-described embodiment, the hollow shaft 5 is reinforced by the first metal cores 6 and 7, and the first slopes 6b and 7b of the first metal cores 6 and 7 are locally formed in the hollow shaft 5. A space 8 is formed, and the wall of the hollow shaft 5 facing the space 8 is formed by the first punch 9 on the first slopes 6 b, 7.
Since the first concave portion 5a is formed by pressing and deforming toward b, the first concave portion 5a is formed with high precision. Further, the primary hollow shaft B in which the first recess 5a is formed is reinforced by the second metal core 10 and one of the first metal cores 7, and the second inclined surface 10c, the flat portion 10b, Local spaces 11 and 12 are formed in the primary hollow shaft B by the first slope 7b, and a shape-retaining punch 13 is fitted into the first concave portion 5a to reinforce the first concave portion 5a so as to reinforce the space portion. The second hollow portion 5b and the third concave portion 5c are formed by pressing and deforming the wall portion of the primary hollow shaft B facing the first and second hollow portions 11 and 12 with the second punch 14 and the third punch 15, respectively. 5b and the third recess 5c are formed with high precision.

Further, the first slope 6 of each of the first metal cores 6, 7 is provided.
b, 7b, and the second inclined surface 10c of the second metal core 10 are inclined upward from the opposite shaft ends toward the opposite shaft ends, so that each of the first metal cores 6, 7 and the second core 10b. Gold 10
Can be easily extracted from the hollow shaft 5, the primary hollow shaft B, and the product A after forming the first concave portion 5a to the third concave portion 5c.

[0013]

As is apparent from the above description, according to the present invention, a pair of metal cores are butt-fitted into a hollow shaft, and a slope and a flat portion inclined in opposite directions are formed in the butt portion. A local space portion is formed in the shaft, and the wall portion of the shaft facing the space portion is pressed by a punch to be compressed and deformed in the axial direction. The effect which can shape | mold is produced.

[Brief description of the drawings]

FIG. 1 is a sectional view of a main part before molding in a first step according to the present invention.

FIG. 2 is a cross-sectional view of a main part after molding in a first step according to the present invention.

FIG. 3 is a cross-sectional view of a main part before molding in a second step according to the present invention.

FIG. 4 is a sectional view of a main part after molding in a second step according to the present invention.

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

FIG. 6 is a cross-sectional view of a main part before molding showing another embodiment of the second step according to the present invention.

FIG. 7 is a cross-sectional view of a main part after molding showing another embodiment of the second step according to the present invention.

FIG. 8 is a cross-sectional view of a main part after a conventional molding.

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

[Explanation of symbols]

 A Product B Primary hollow shaft 5 Hollow shaft 5a First concave portion 5b Second concave portion 5b 'Second concave portion 5c Third concave portion 6 First metal core 6a Shaft end 6b First slope 7 First metal core 7a Shaft end 7b 1 slope 8 space 9 first punch 9a pressure projection 10 second core 10 'second core 10a shaft end 10a' shaft end 10b flat 10c second slope 10c 'second slope 11 space 12 space Part 12 'Space part 13 Shape-retaining punch 14 Second punch 15 Third punch 16 Spring

Claims (2)

(57) [Claims] 1. A pair of first metal cores each having a first inclined surface which is inclined radially outward toward an opposite axis end at opposite shaft ends is provided, and the first inclined surfaces are opposed to each other. The first metal core is fitted in a hollow shaft made of metal, and the wall of the hollow shaft facing each first slope is compressed in the axial direction by a V-shaped first punch to form a first concave portion to form a primary recess. Provide a hollow shaft,
A second core is provided at the shaft end, the second core having a flat portion parallel to the axis and a second slope inclined radially outward from the base of the flat portion toward the opposite shaft end. The gold and one of the first metal cores were fitted into the primary hollow shaft with the second slope and the first slope facing each other, and a V-shaped retaining punch was fitted into the first recess. Thereafter, the wall of the primary hollow shaft, which is adjacent to the first recess in the axial direction and faces the second slope, is compressed in the axial direction by the V-shaped second punch to form the second recess. A method for forming a concave portion of a hollow shaft. 2. The second core bar and one of the first core bars are fitted into the primary hollow shaft with the second slope and the first slope facing each other, and the second slope and the first slope are connected to each other. The first inclined surface of the first metal core is separated from the first concave portion on both sides in the axial direction, and a V-shaped shape-retaining punch is fitted into the first concave portion. The wall of the primary hollow shaft facing the first inclined surface of the first metal core is compressed in the axial direction by a V-shaped second punch and a third punch to form a second recess and a third recess. The method for forming a concave portion of a hollow shaft according to claim 1.