JPH0140608Y2 - - Google Patents

Description

[Detailed Description of the Invention] (Industrial Application Field) The present invention relates to a spline piece cold forging die useful for manufacturing spline pieces used, for example, in automobile gear clutches.

(Prior Art) This type of spline piece has conventionally been produced by cold forging, specifically, as shown in FIG. and forming channel projections 11 on the entire outer circumferential surface of the material 10 to form a channel molding piece 12 (FIG. B, b). The extrusion molding step (C, c in the same figure) to form the tooth-shaped extruded piece 13 by forming the entire outer periphery of the spline piece 12, and removing the burr on the outer periphery of the molded piece caused by the tooth-shaped extrusion, make the spline piece 1
It is manufactured through the deburring process (D and d in the same figure), which is completed in step 4.

Conventionally, the tooth profile extrusion process described above involves an extrusion die 1 (having a die surface 4 on the bore side wall corresponding to the side tooth profile of the spline piece) and an extrusion die 1 located above the die, as shown in FIGS. 6 and 7. punch 15
(having a circular bottom surface 18 as shown in FIG. 8), the chamber molding piece 12 is placed on the bore of the extrusion die 1 and struck from above with a punch 15. In this case, in order to prevent deformation and damage of the extrusion die 1,
It is necessary to provide a 1.5 mm burr section 9 on the outer periphery of the product section 8 of the resulting piece 13.

In addition, in the next deburring step, as shown in FIG. 9, on a cutting die 16 having a die surface similar to the tooth-shaped die surface 4 of the extrusion die 1 and enlarged by about 0.2 mm overall, By placing the toothed extrusion piece 13 and subsequently applying plastic working pressure, the product part 8 is
This was done by separating the burr portion 9 along the die surface of the cutting die 16 to obtain a spline piece product.

(Problem to be solved by the invention) However, in this deburring process, it is not easy to accurately align the phase between the tooth profile surface of the product part 8 of the piece and the mold surface of the cutting die 16, and the phase alignment work is very difficult. It was troublesome, and sometimes the deburring process was performed with the phase shifted, resulting in a defective spline piece with a mold misalignment part 17 as shown in FIG. 10.

The purpose of this invention is to solve the above-mentioned problems and to be able to remove burrs more quickly.
Moreover, it is an object of the present invention to provide a cold forging die for a spline piece that eliminates the occurrence of defective products due to die misalignment.

(Means for Solving the Problems) The cold forging die for spline pieces of the present invention includes an extrusion die having a die surface corresponding to the side tooth profile of the spline piece, and the extrusion die as a die for extruding the tooth profile of the spline piece. An inner punch and an outer punch are located above and are divided into two parts, an inner punch and an outer punch, with a curved surface corresponding to the tooth profile of the bottom surface of the spline piece as the boundary, and are arranged so that the lower surface of the inner punch protrudes from the lower surface of the outer punch. It is characterized by: That is, in the cold forging die of the present invention, the tooth profile extrusion punch, which has conventionally had an integral structure, has a curved surface corresponding to the bottom tooth profile of the spline piece, preferably a curved surface of the same size as the tooth profile die surface of the extrusion die. Or, with a similar curved surface reduced by about 0.2 to 0.3 mm, divide it into an inner punch and an outer punch, and make the lower surface of the inner punch smaller than the lower surface of the outer punch, preferably about 1/2 the thickness of the burr part. It is something that stands out.
When the mold of the present invention is applied, it is fixed to a die set so that the tooth profile of the divided curved surfaces of the inner punch and outer punch match the tooth profile of the mold surface of the extrusion die.

(Function) When the cold forging die of the present invention is used, tooth profile extrusion processing is performed by placing the chimney molded piece on the extrusion die and hitting it with both the inner and outer punches in the same way as in the past. A toothed extrusion piece having sections is fabricated. However, since the cold forging die of the present invention is set with the lower surface of the inner piece protruding from the lower surface of the outer piece, the chamfer forming piece is extruded by this amount of protrusion, resulting in a step between the product part and the burr part. The resulting tooth-shaped extruded piece is manufactured, and the burr part does not become thin.
The separation surface length between the product part and the burr part is shortened.
Therefore, the burr can be removed using a cutting die having a circular hole that supports only the burr portion, and there is no need to align the tooth-shaped extruded piece and the cutting die.

(Example) Embodiments of the present invention will be described below with reference to the drawings.

As shown in FIGS. 1 and 2, the cold forging die of the embodiment includes an extrusion die 1, an inner punch 2, and an outer punch 3 as a die for extruding the tooth profile of a spline piece. The extrusion die 1 has a die surface 4 on its bore side wall corresponding to the side tooth profile of the spline piece, and the inner punch 2 and the outer punch 3 correspond to the bottom tooth profile of the spline piece, as shown in FIG. It is divided in the vertical direction by a curved surface 5 having a similar shape, that is, the same size as the extrusion die surface 4 or about 0.2 to 0.3 mm smaller than the extrusion die surface 4, and as shown in FIG. The device is arranged so that the lower surface of the punch protrudes from the lower surface of the outer punch by a distance t (approximately 1/2 of the burr thickness). Note that 7 indicates knockout, which is used to take out the toothed extruded product.

Next, the tooth profile extrusion process using this mold will be explained. A chimney molded piece is placed on the extrusion die 1, and then the inner punch 2 and the outer punch 3 are struck from above. At this time, the outer punch 3 is brought close to the extrusion die 1 to the required burr thickness interval (0.8 to 1.5 mm). As a result, a burr portion 9 of the required thickness is formed on the entire outer periphery of the product portion 8.
and separation surface length of burr portion 9 (distance l in Figure 2)
Tooth-shaped extruded piece 1 whose thickness has been reduced to about half of the burr thickness
3 will be produced. Therefore, in the next deburring process, as shown in FIG.
By placing it on top so that only the burr part 9 is supported and press working, the burr part 9 is removed.
can be removed to obtain a spline piece product with a complete tooth profile.

(Effects of the invention) The cold forging die for spline pieces of the present invention has the required thickness of the burr part and the separation surface length of the product part and the burr part is longer than that of the conventional cold forging die for spline pieces. It is possible to manufacture a tooth profile extrusion piece that is shorter than that of the conventional method, and therefore, a cutting die without a tooth profile surface can be used in the next deburring process, and the phase alignment of the tooth profile, which was conventionally performed, is no longer necessary. Therefore, the burr portion can be removed more quickly, and there is no possibility of producing defective products due to mold misalignment.

[Brief explanation of the drawing]

FIG. 1 is a diagram showing the tooth profile extrusion process of a spline piece using a cold forging die according to an embodiment of the present invention;
Fig. 2 shows the main part of the tooth profile extrusion process shown in Fig. 1, Fig. 3 shows the bottom of the punch of the cold forging die of Fig. 1, and Fig. 4 shows the cold forging die of the example. Figure 5 is a diagram showing a series of manufacturing processes for a spline piece when used, Figure 6 is a diagram showing a tooth profile extrusion process for a conventional spline piece, and Figure 7 is a diagram showing a process for extruding a conventional spline piece. Figure 6 shows the main parts of the tooth profile extrusion process, Figure 8 is a bottom view of the punch shown in Figure 6, Figure 9 shows the conventional spline piece deburring process, and Figure 10 shows the conventional spline piece extrusion process. It is a figure which shows the defective tooth profile part of a spline piece. In the figure, 1...extrusion die, 2...inner punch, 3...
...Outer punch, 4...Mold surface, 5...Curved surface, 8...Product part, 9...Burr part, t...Protrusion amount.

Claims (1)

[Scope of utility model registration request] The mold for extruding the tooth profile of the spline piece includes an extrusion die having a mold surface corresponding to the side tooth profile of the spline piece, and an extrusion die located above the extrusion die that has a curved surface corresponding to the bottom tooth profile of the spline piece as a boundary. A cold forging die for a spline piece, comprising an inner punch and an outer punch which are divided into two parts and are arranged so that the lower surface of the inner punch protrudes from the lower surface of the outer punch.