JPH03133B2 - - Google Patents

Description

Detailed Description of the Invention (Industrial Field of Application) The present invention provides a method for strengthening the boundary between the flange and the rod-shaped portion of a support shaft having a polygonal flange, such as a bolt or a support shaft of a caster. The present invention relates to a method of manufacturing a support shaft having a flange that can be formed into a flange.

(Prior Art) For example, a conventionally used support shaft 31 for a caster is compressed in the axial direction by so-called header processing into a shape as shown in FIG. As shown in FIG. 6, this support shaft 31 has a rod-shaped portion 33 fixed to a vehicle body such as a transport vehicle, and firmly supports a wheel 35 between a flange portion 32 and a breakout portion 34. be.

(Problems to be Solved by the Invention) In the above-mentioned conventional method for manufacturing a support shaft, when the flange portion 32 is subjected to header processing, the metal structure of the material is unreasonably bent at the base of the flange portion 32. There is a disadvantage that a weakened portion is formed, and cracks are likely to occur in the portion indicated by line C in FIG. 5 when a strong impact is received from the outside. In addition, when the flange 32 is polygonal, the polygonal flange 32 is formed by compression molding the circular flange and then cutting off the periphery into a polygonal shape. This poses a problem in that it impedes the ability of the government to operate and promotes weakening. This problem is not limited to caster support shafts, but is also common to bolts having polygonal flanges and other support shafts.

The present invention eliminates the drawbacks of the above-mentioned conventional methods for manufacturing support shafts having polygonal flanges, such as caster support shafts and bolts, and manufactures strong support shafts that have high strength against external impacts. The aim is to provide a method to do so.

(Means for solving the problem) A support shaft having polygonal flange portions 2, 22 and rod-like portions 3, 23 is manufactured by compressing a bar-shaped metal material in the axial direction using two male and female molds. In the method of
a female mold 13 with a rod-shaped part 3 of the collar part 2,
Using a male die 15 equipped with an annular convex portion 16 for forming an annular groove 5, 25 having an arcuate cross section along the periphery of the joint with the metal rod 23, two male and female dies 13, 15 are used to form a rod-shaped metal material. By squeezing in the axial direction of
The polygonal flanges 2, 22 and the annular grooves 5, 25 are molded at the same time, and a good continuous state is maintained without breaking the connection of the metal structure in the pressed part of the material, and the flanges 2, 22 and the rod are molded simultaneously. A method of maintaining the joints with the shaped parts 3 and 23 firmly was adopted.

(Function) In the present invention, the female mold 13 is equipped with a polygonal recess 14 that regulates the outer shape of the polygonal collar portions 3 and 23.
and a male die 15 having an annular convex portion 16 for forming an annular groove 5, 25 having an arcuate cross section along the periphery of the joint between the collar portions 2, 22 and the rod-like portions 3, 23.
By compressing the rod-shaped metal material in the axial direction with two molds, polygonal flanges 2, 22 on the support shaft 1 are formed.
Since the annular grooves 5 and 25 are molded at the same time,
As a result of the annular grooves 5 and 25 pushing the flow of the metal structure inward, no unreasonable bending occurs, and the connection of the metal structure in the compressed portion of the material continues well without breaking. In addition, the polygonal flange 2,
22 at the same time, there is no cutting of the metal structure due to conventional cutting around the flange parts 2, 22.
The joint between the rod-like portions 3 and 23 can be firmly maintained.

(Example) An example of implementing the present invention is shown in FIGS. 1 to 4. Fig. 1 is a perspective view of a caster spindle and bolt molded by the method of the present invention, Fig. 2 is a sectional view showing the flow state of the metal structure of the caster spindle and bolt, and Fig. 3 is a perspective view of the caster spindle and bolt. FIG. 4 is a cross-sectional view showing a mold for forming the support shaft, and FIG. 4 is a cross-sectional view of the support shaft assembled into the caster.

1 to 4, a support shaft 1 for a caster consists of a polygonal flange 2, a rod-shaped portion 3, and a protrusion 4, and the base of the flange has an annular groove with an arcuate cross section. 5 is formed. As shown in FIG. 4, an upper plate 6 is fitted into the protruding part 4 along the lower side of the flange part 2, and a wheel 7 is supported at the lower part of the protruding part 4 via a large number of rolling balls 7. A leg 10 is rotatably fitted, and a lower plate 11 is attached to the lower part of the leg 10 via a rolling ball 8.
are fitted, and these are fixed to the protruding part 4 by making the top of the protruding part 4 into a hammer 12.

To form this support shaft 1, as shown in FIG. Using a male mold 15 equipped with an annular convex portion 16 for forming an annular groove 5 having an arcuate cross section along the periphery of the joint with the male and female molds 13 and 15, a bar-shaped metal material is axially By squeezing it into a polygonal flange 2
and the annular concave groove 5 are simultaneously molded to maintain a good continuous state without breaking the connection of the metallographic structure in the pressed part of the material, making it possible to maintain a strong joint between the flange part 2 and the rod-shaped part 3. I did it like that.

Figures 1B and 2B show a bolt 21 formed by applying the present invention, which has approximately the same structure as the caster spindle 1 except that it does not have the protrusion 4. Polygonal head (flange part) 2
2, a rod-like portion 33, and an annular groove 25 having an arcuate cross section. Therefore, the manufacturing method thereof is also similar to that of the above-mentioned caster spindle, so the explanation will be omitted.

In the spindle 1 and bolt 21 formed in this way, the flow of the metal structure is pushed inward by the annular grooves 5 and 25, so that unreasonable bending does not occur and the connection of the metal structure in the pressed part of the material is not broken. Good continuity. In addition, the polygonal flange 2,
22 is compressed and molded at the same time as the rod-shaped parts 3 and 23, so there is no cutting of the metal structure that accompanies conventional cutting of the surrounding area, and the joint between the collar parts 2 and 22 and the rod-shaped parts 3 and 23 is maintained firmly. This makes it far superior in strength to conventional support shafts or bolts.

Comparing the thus formed support shaft 1 and bolt 21 with the conventional support shaft 31 with reference to FIGS. 2 and 5 showing the flow state of the metal structure, first, as shown in FIG. , in the case of the conventional one, the streamline B indicating the flow of the metal structure is between the flange part 32 and the rod-shaped part 33.
Because it is cut by forced refraction near the periphery of the joint with the polygonal flange 32, and cut by cutting around the polygonal flange 32, the part indicated by the chain line C becomes weakened, and if a strong impact is received from the outside, this part will break. cracks occur. In order to avoid the occurrence of such cracks, caster spindles are conventionally normalized at approximately 750°C after compression molding.
As a result, the material becomes soft and bends easily due to external forces. On the other hand, the spindle manufactured by the method according to the present invention, as shown in FIG.
The streamline A indicating the flow state of the metallographic structure continues without interruption on the outer surface of the support shaft 1 and the bolt 21, good connection of the metallographic structure is maintained, and high strength can be obtained in the compressed portion. Therefore, no additional normalizing step is required, and labor and thermal energy can be significantly saved.

Although a support shaft for a bolt and a caster has been described here as an example, it is clear that the idea of the present invention is generally applicable to the manufacture of shafts having other flanges.

(Effects of the Invention) As described above, in the present invention, a rod-shaped metal material is compressed in the axial direction using two male and female molds to provide polygonal collar portions 2, 22 and rod-shaped portions 3, 23. In the method of manufacturing a support shaft, polygonal flanges 2, 22
A female mold 1 with a polygonal recess 14 regulating the outer shape of the
3 and a male mold 15 equipped with an annular convex portion 16 for forming grooves 5, 25 having an arcuate cross section along the periphery of the joint between the flanges 2, 22 and the rod-like portions 3, 23,
By compressing the rod-shaped metal material in the axial direction with two male and female molds 13 and 15, the polygonal flange 2 and the annular grooves 5 and 25 are simultaneously molded. The flange portions 2, 22 and the rod-shaped portions 3, 2 are connected by keeping the connection of the metal structure in a good continuous state without breaking it due to excessive bending or cutting.
3 can be maintained firmly, and there is no need for subsequent heat treatment such as normalizing, thereby reducing manufacturing costs.

[Brief explanation of the drawing]

1 to 4 show an example of the implementation of the present invention, and FIG. 1A shows a caster spindle molded by the method of the invention, and FIG. 1B shows a bolt molded by the method of the invention. 2A is a perspective view of the caster spindle formed by the method of the present invention, FIG. 2B is a sectional view showing the flow state of the metal structure of the bolt formed by the method of the present invention, and FIG. A cross-sectional view showing a mold for forming a support shaft for casters, FIG. 4 is a cross-sectional view of the support shaft assembled into a caster, and FIG. 5 shows the flow state of the metal structure of a conventional support shaft for casters. A sectional view, FIG. 6 is a sectional view of the support shaft assembled into a caster. DESCRIPTION OF SYMBOLS 1... Support shaft, 2... Polygonal flange, 3... Rod-shaped part, 5... Annular recess, 13... Female type, 14... Polygonal recess, 15... Male type, 16... Annular convex portion, 2
1... Bolt, 22... Polygonal flange, 3, 23...
...rod-shaped part, 5, 25... annular groove.

Claims (1)

[Claims] 1. In a method for producing a support shaft having a polygonal flange and a rod-like part by compressing a rod-shaped metal material in the axial direction using two male and female molds, the outer shape of the polygonal flange is restricted. Using a female mold having a polygonal recess and a male mold having an annular convex groove for forming an annular groove having an arcuate cross section along the periphery of the joint between the flange and the rod-like part, By compressing the rod-shaped metal material in the axial direction using two male and female molds, a polygonal flange and an annular groove can be simultaneously molded, and a good connection between the metal structures in the pressed portion of the material can be achieved. A method for manufacturing a support shaft having a flange, characterized in that the joint between the flange and the rod can be firmly maintained by maintaining the joint in a continuous state.