JPH0223257B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for manufacturing a cylindrical shaft with a collar.

The shaft shown in FIG. 1 used for the shaft of an automobile retractor, etc. has a cylindrical shaft 1.
A collar 2 is provided at one end, a gear 3 is provided on the outer peripheral surface of the collar 2, and an axial hole 4 is bored in the peripheral wall of the shaft 1.

Conventionally, as shown in FIG. 2, the above-mentioned shaft is made of a long, small-diameter material 5 and a large-diameter, short bar material 6.
and a flat disk-shaped plate 7 are processed using different processing methods to form the shaft 1, the collar attachment member 8, and the collar 2, and these three members are assembled into one body by caulking and assembly. are doing. In order to process the above-mentioned material 5 into the shaft 1, the bar material 5 is first
It is formed into a cylindrical shape using a hot forging method, and a small-diameter protrusion 9 is formed at both ends, and a hole 4 is formed in the peripheral wall. In order to insert the portion 9 into the collar attachment member 8, cutting of the portion 9a is required. Also,
A concave portion 10 is formed in the bar 6 by cold forging, and a collar attachment member 8 is provided by performing four to five cutting steps. Further, the plate material 7 has a shaft hole formed by press working, and a gear is formed on the outer peripheral surface. In this way, conventionally hot forging, cold forging,
Three parts are constructed using various processing methods such as cutting and press processing, and these are assembled into a single piece by crimping, which results in poor productivity and high cost due to the large number of processing points and processes. However, hot forging had various drawbacks such as poor shape and dimensional accuracy.

The present invention aims to solve the above-mentioned conventional drawbacks, and provides a manufacturing method in which a rod-shaped material is formed into a flanged shaft by integral processing using a cold forging method. Specifically, the present invention first constrains one end of a rod-shaped material, and forms a ring-shaped body by boring a hole in the other end surface by backward extrusion. A collar is formed by protruding the material into a gear bit formed by a lower mold having a large diameter portion and an upper mold supported by back pressure, and then the hole is extended along the axis by extrusion processing. As a cylindrical shaft,
Next, a forming process is performed to stretch the brim to a large diameter and a thin width, and then a bending trim process is performed to make a hole in the peripheral wall of the cylindrical shaft.Finally, a trim process is performed to form a gear on the outer circumferential surface of the brim. The present invention provides a method for manufacturing a shaft with a flange by integrally processing a rod-shaped material by cold forging.

Hereinafter, the present invention will be explained in detail with reference to embodiments shown in the drawings.

Figure 3 shows a rod-shaped material 11 processed through six steps.
This figure shows the process of manufacturing a shaft 12 with a collar provided with gears on the outer circumferential surface. First, a rod-shaped material 11 is cut to a predetermined length, and a hole 13 is formed from the upper end surface using an upsetting process using a cold forging method. At the same time as drilling, hole 1
A collar 14 is made to protrude from the outer periphery of 3. This upsetting process is performed using an upsetting device A shown in FIG. 4, when a punch 15 is driven into the upper end surface of the rod-shaped material 11, an upper die 16 and a lower die 17 are used to place the collar 14 into a predetermined position from the upper end surface of the hole 13. The holes 13 are set so as to protrude from the outer peripheral surfaces of the holes 13 at intervals. Therefore, in the upsetting apparatus A, first, one end of the rod-shaped material 11 is placed in the lower die 1.
7, and punch 1 on the other end surface of the rod-shaped material 11.
5, a hole is formed in the upper side in the figure by backward extrusion processing, and the annular body 20 is formed. At the same time, in a cavity 51 having a larger diameter than the annular body 20 formed by the lower mold 17 and the upper mold 16 supported by back pressure from a spring 50,
A collar 14 is formed at the bottom of the annular body 20 by protruding the material. Therefore, by adjusting the back pressure of the upper mold 16 loaded by the spring 50,
The thickness of the brim 14 to be formed and the ratio of the extruded length of the annular body 20 can be easily controlled.

After the upsetting process described above, extrusion process is performed. A punch 18 is driven into the hole 13 by the extrusion processing apparatus B shown in FIG.
to form. At this time, a small-diameter protrusion 24 is formed on the bottom surface of the shaft 21 by the molds 22 and 23.

Next to the extrusion process, the collar 14 is expanded outward to form a thin, large-diameter collar 15, and the hollow part is formed by a molding device C shown in FIG. At the same time as the punch 25 is inserted into the flange 19, the collar 14 is pressed by the upper die 26 and the lower die 27 to form a stretched collar 15. At this time, the flange 15 has a tapered shape (angle θ) that slopes upward toward the outside on the upper surface 15a side, and the flange 15 becomes thicker toward the outside, so that the outer peripheral end is the widest. is formed.

Next to the above-mentioned forming process, holes 3 in the axial direction are formed in the peripheral wall of the shaft 21 from below the collar 15 to near the lower end.
0 is formed by bending and trimming. As shown in FIG. 7, the bending and trimming process is performed by first punching a punch hole 46 as shown in FIG.
A recess 34 is formed at a position facing 6, and finally, a hole 30 is provided at the bottom of the recess 34 as shown in FIG. The bending and trimming process is as shown in FIG.
First, the shaft 21 is supported in the bending trim processing device D as shown in a, and the hollow part 19 of the shaft 21 is
The mandrel 32 is fitted to the core 32, and the punch hole 36 is punched out by driving the punch 33a. Next, as shown in b, the shaft 21 is rotated 180 degrees, and the punch 33b is driven into the position facing the punch hole 36, and the side wall portion 2 is
A curved recess 34 is formed in 1a. Finally, as shown in FIG. 8c, a punch 33c is driven into the bottom of the recess 34 to form a hole 30.
Therefore, the holes 30 are formed in the bottom surfaces of both side walls 35 that are curved inward.

After bending and trimming the hole 30, the collar 1
A gear 36 is formed on the outer peripheral surface of 5 by trimming.
Since the gear 36 is formed with a thick outer circumferential surface that tapers upward, even if a load is applied to the gear 36, the load applied to the entire collar 15 is reduced, and the strength of the collar 15 is improved.

Note that the collar 15 does not necessarily need to be provided with a gear, and may be provided with a mechanical element such as a pulley or cam shape depending on the use of the shaft.

As described above, according to the manufacturing method of the present invention, a cylindrical shaft with a collar can be manufactured by sequentially performing upsetting processing, extrusion processing, and forming processing using a cold forging method on a bar material. . After forming the flanged shaft, depending on the use of the shaft, for retractor shafts, holes may be made by bending and trimming, and then gears may be formed by trimming, which is a simple process for processing one material. Manufactured by In addition, in order to form a solid shaft with a collar, it can be manufactured more easily by omitting the extrusion process.

As is clear from the above explanation, according to the manufacturing method according to the present invention, a shaft with a collar, which was conventionally formed by assembling three parts formed using different processing methods, can be produced using a cold forging method. 1 with integrated processing by
A shaft with a collar can be manufactured from two materials. Therefore, the number of processing steps can be greatly reduced, productivity can be improved, and costs can be reduced.
Furthermore, since the process is performed using a cold forging method, dimensional accuracy is improved compared to a hot forging method. Furthermore, since the shape of the brim is tapered, the load can be reduced and the strength can be improved, among other advantages.

[Brief explanation of drawings]

Fig. 1 is a front view of a retractor flanged shaft manufactured by a conventional manufacturing method, Fig. 2 is a process diagram showing the conventional manufacturing method, and Fig. 3 A to F are a manufacturing method of a flanged shaft according to the present invention. FIG. 4 is a cross-sectional view of the upsetting device, FIG. 5 is a cross-sectional view of the extrusion device, FIG. 6 is a cross-sectional view of the forming device, and FIG.
Figure ~ is a schematic diagram showing the bending and trimming process sequence,
8a to 8c are cross-sectional views of the bending and trimming device. 11... Rod-shaped material, 12... Shaft with collar,
13... Hole, 14, 15... Collar, 19... Hollow part, 20... Annular body, 21... Shaft, 36...
... Gear, A ... Upsetting processing device, B ... Extrusion processing device, C ... Forming processing device, D ... Bending / trim processing device.

Claims (1)

[Claims] 1. A rod-shaped material is processed by cold forging, one end of the material is restrained, and a hole is bored in the other end surface by backward extrusion processing to form an annular body, and at the same time, a hole is formed on the outside of the annular body. In addition, a collar is formed by protruding the material into a gear bit formed by a lower die having a diameter larger than that of the annular body and an upper die supported by back pressure, and then extrusion processing is performed to align the hole with the axis. A hollow part is formed along the shaft to form a cylindrical shaft, and then,
A method for manufacturing a shaft with a flange, which comprises performing a molding process to form the flange into a thin width with a large diameter, and at the same time forming the flange into a tapered shape that becomes thicker toward the outer periphery. 2. In the manufacturing method according to claim 1, after the above-mentioned forming process, an axial hole is formed by bending and trimming the peripheral wall of the cylindrical shaft, and then gears, cams, etc. are formed on the outer peripheral surface of the collar. A method for manufacturing a shaft with a collar, which is characterized by molding mechanical elements such as levers.