JPS6068124A - Working method of shaft - Google Patents

Abstract

PURPOSE:To reduce the weight of a shaft and man-hour by forcing punches to both opposed side walls in the central part of a blank material to form groove parts by forcing and bulging of the side walls and blanking the bottom walls of said groove parts to form a groove hole. CONSTITUTION:A blank pipe 10 in which a low melting alloy 11 is packed is inserted into segmental dies 12 and punches 13A, B are forced into the opposed side walls of the pipe 10 to bulge the side walls 15A, B of the pipe 10 by the plastic flow of the material 11 thereby expanding the central part. Groove parts 14A, B are formed to both side walls in the central part 16 except the top and bottom ends 17, 18 of the pipe 10 by such forcing and bulging of the side walls. Stepped shaft parts 19, 20 are formed by pressing to the ends 17, 18 and thereafter a groove hole 21 is punched to the parts 14A, B. The material 11 is melted away. The weight of the shaft and the man-hour for working are thus reduced.

Description

DETAILED DESCRIPTION OF THE INVENTION Product 1 The present invention relates to a method for processing a shaft, and in particular, a shaft for a retractor around which a safety belt of an automobile is wound, which has a groove along its axis and has a groove at both ends. Shirts 1 to 1 having a shape with a fixed shaft protruding from the top can be processed extremely easily, and the weight of the shaft can be reduced.

[Set 11] Conventionally, as shown in FIG. 1, a retractor shaft 1 is mounted on a frame 3 with a gear 2 attached to one end, and one end of a belt 4 is locked in a groove 18 of the shaft 1, The belt 4 is wound around the outer circumferential surface of the shaft 1 (tl) and the belt 4 is stored, and when the bell l-4 is used, the belt 4 is wound back from the shaft 1. 1 requires strength because it applies a strong force to the belt 4 to wrap and unwind it, and therefore, the belt 4 in FIG.
), a round bar-shaped steel material 5 is hot-forged and cut into one piece, and a gear 2 is attached to the shaft 1 via a gear attachment member 6 as shown in FIG.

In order to form the shaft 1 in one piece as described above, the material 5 shown in FIG. 2 (A) is hot forged in four steps (B
), a fixed shaft part 7.8 is provided protrudingly on both ends, and four parts 9 and 10 are recessed in the opposing outer periphery of the solid shaft part, the bottom surface of the groove part is cut out, and then steps 4 to 5 are made. In the cutting process, the outer peripheral part of the shaft 1 and the fixed shaft part 7.8 are finished, and the side surface of the shaft 1 is machined to form the J shape shown in C) and (D).
1 to 1 are manufactured. The shape of the belt 1M1a is technically difficult to process because it has a complicated shape as shown in the figure, with wide openings at both ends and a narrow center in order to engage the tip 4a of the belt 4.

Since the shaft 1 is manufactured as described above, there are many processing steps, resulting in poor productivity and high cost.In addition, the shape and dimension accuracy is poor because it is hot forged, and because the shaft is formed from a round bar. There were various drawbacks such as increased weight.

This invention aims to eliminate the above-mentioned drawbacks, and aims to reduce the mold opening by using a hollow material, and
The hollow material is bulge-formed by pushing the side walls to form a complex-shaped groove, and the bottom wall of the waist is punched and processed to form a slotted hole, thereby reducing processing man-hours and improving productivity.
The purpose is to reduce costs, etc.

This invention aims to achieve the above-mentioned object, and the present invention aims to achieve the above-mentioned object by punching a blank pipe of a predetermined length made of a round pipe on both side walls facing the center part of the blank pipe, excluding both upper and lower ends. The grooves are formed facing each other by side wall pressing and bulge forming, and the tube is expanded to form stepped shaft portions with a smaller diameter than the center portion at both ends of the lower part of -L, and then the bottom walls of the opposing vortex portions are punched out. The present invention provides a shaft machining method characterized by forming slotted holes.

EXAMPLES Hereinafter, this invention will be explained in detail with reference to examples shown in FIG. 4 and below.

First, as shown in FIG. 4, a low melting point alloy 11 is filled into a blank pipe 10 of a predetermined length, which is a round pipe with a circular cross section.

Next, as shown in FIG. 5, the raw tube 10 filled with the low melting point alloy 11 is inserted into the split die 12 to support both upper and lower ends of the raw tube 10, and the side walls in the die 12 (see FIG. (A)
), push the left and right punches 13Δ, 13B of desired shapes as shown in FIGS. As a result of this pushing, as shown in (C), the filling material 11 in the central part of the raw pipe 10 undergoes plastic flow as shown by the arrows in the figure, and moves to both sides perpendicular to the punch pushing side. The side wall 15A of the raw pipe 10
, 153 swells from the chain line position to the solid line position, and the central portion is expanded. By this side wall pressing bulge forming, as shown in FIG.
Grooves 14A and 14B with desired opening ends that are wide and narrow inward are formed on the opposite side walls of the tube 6, and small diameter portions 17 that are smaller in diameter than the center portion are formed at both upper and lower ends of the raw pipe 10.
．． 18 is molded.

Next, as shown in FIG. 7, the upper part of the raw pipe 10 is press-worked to correct the radius of the connecting part between the small diameter part 17 and the central part 16, and the small diameter part 17 is made into a rectangular cross-section so that it is separated from the central part 16. Forming the stepped shaft portion 19 that continues in a shape, and at the same time,
The lower part of the raw pipe 10 is also formed into a stepped shaft part 20 having a circular cross section by press working.

After the above straightening process, the joined groove bottom wall 14. A, -1
14B-1 is punched to form a slot 21.

After forming the shaft into a desired shape through the above processing, it is heated to melt the low melting point alloy 11 filled in the tube 10 and removed.

By the above processing method, the central portion 16 as shown in FIG.
It has a slot 21 for hanging a belt which is long in the axial direction and has wide openings at both ends and a narrow central communication part, and a stepped shaft part 1 at both ends.
9.20.

As shown in FIG. , and lock one end of it into the narrow communication hole in the center with a screw.
I am using it.

1 As is clear from the above description, according to the method for manufacturing the shirt 1- according to the present invention, after forming a groove in the center portion and stepped portions in both E portions of a round pipe by sidewall pushing and bulge forming, Since the desired grooved and stepped shafts are manufactured by punching the bottom wall, the desired shafts can be manufactured extremely easily with a small number of machining operations, improving productivity and reducing costs. In addition, since it is manufactured from round pipes, it is significantly lighter and smaller, and the bulge molding eliminates the need for complex 7
Since five parts are molded, it has various advantages such as improved dimensional accuracy.

[Brief explanation of the drawing]

Figure 1 shows the shaft for a beam tractor. A) is a process diagram without showing the method, and (D) is a sectional view taken along the line D-D of (C). The drawing, 4th
8 to 8 show the process of assembling the shaft according to the present invention, and FIG. 4 is a cross-sectional view of the raw pipe filled with filler;
Figure 1 shows the bulge forming method.A) (A sectional view showing the state inserted into the bulge (13) is a sectional view showing the state in which the punch is in operation.(C) is a horizontal sectional view of (r3). Figure 6 shows the state of the raw pipe after bulge forming.
The figure is a cross-sectional view of the brace I culm, and Figure 8 is the normal 10.
...Main pipe, 11...Low melting point alloy, 12...Die, 1
3Δ. 13B...Punch, 14A, 14B...Groove, 1
9.20...Stepped shaft portion, 21...Slot hole. Patent applicant: Tokai Rika Denki Seisakusho Co., Ltd.

Claims (1)

[Claims] (1) A blank pipe of a predetermined length made of a round pipe is formed by pushing a punch into both walls facing the center, excluding the top and bottom ends of the blank pipe, and forming the grooves so that they face each other by side wall push-in bulge forming, and expanding the pipe. A method for processing a shaft, characterized by forming stepped shaft portions having a smaller diameter than the central portion at both upper and lower ends, and then punching out the bottom walls of the opposing vortex portions to form slots.