JPH0688095B2 - Viscous coupling molding method - Google Patents

Description

TECHNICAL FIELD The present invention relates to a punch having an annular projection formed on a peripheral edge of a tip surface and external teeth for forming a spline tooth profile (hereinafter simply referred to as external teeth) on an outer peripheral surface. The present invention relates to a method for forming a viscous coupling in which a spline tooth profile is formed on the inner peripheral surface of a material by pushing the material into a die while pushing the material into a cup-shaped material having an annular clearance groove on the bottom surface.

(B) Prior art As a method of molding the above-mentioned viscous coupling, as described in, for example, Japanese Patent Application Laid-Open No. 1-205841 and Japanese Patent Application Laid-Open No. 1-215429, a cup-shaped material in which rough teeth are previously formed on the inner peripheral surface is used. The inner circumference of the material while pressing the opening side of the material with the punch while always restraining the inner circumference of the material with the outer teeth while pressing the punch with outer teeth on the peripheral surface. There is known a technique for finishing and forming a spline tooth profile.

(C) Problems to be Solved by the Invention In the conventional method, since the external teeth have a length comparable to the spline tooth profile of the product, the spline tooth profile was formed during the punch pressing process. The extra thickness cannot escape to the rear of the external teeth, and rough teeth must be formed on the inner peripheral surface of the material in advance.

Therefore, it is necessary to align the rough teeth with the outer teeth when forming the rough teeth and setting the material.

Further, since the outer teeth of the punch mesh with the spline tooth profile of the material over the entire length in order to always restrain the inner peripheral surface of the material, the formation of the spline tooth profile is limited to only the process of pushing the material into the die.

D Means for solving the problem The present invention is a method for molding a viscous coupling excellent in tooth profile accuracy by a simple and rational means,
The structure shows that the punch has outer teeth only on the tip of the punch, and the front and rear ends of the outer teeth are provided with guide taper, and the die has a wider approach on the punch pushing side. Further, the outer diameter of the material is at least less than or equal to the diameter of the approach portion in the die, first in the first step, the punch is pushed into the cup-shaped inner entrance of the material set in the approach portion, and in the second step, the While pushing the punch further into the cup shape, the material is pushed into the die by the punch, and stopped immediately before the end surface of the annular projection of the punch comes into contact with the bottom surface of the annular clearance groove of the material. The purpose is to form a spline tooth profile on the inner peripheral surface of the cup-shaped material by pulling out a punch from the material.

E. Action The raw material in which the punch has been pressed in the first step is pushed into the die while being squeezed by the punch in the second step, whereby pre-formed spline grooves are formed on the inner peripheral surface of the material.

In the subsequent third step, the surplus inwardly squeezed out by the preforming is squeezed out to the outside when the final forming is performed. Example A method for forming a viscous coupling according to the present invention will be described with reference to the drawings. .

In FIG. 1, 1 is a punch, 2 is a die, 3 is a material, the punch 1 is a columnar shape and reciprocates in the vertical direction, and an annular projection 4 is provided on the outer peripheral portion of the tip surface and the tip portion is The outer teeth 5 are provided around the.

As shown in FIG. 6, a taper TT for guiding is provided at both front and rear ends of the outer tooth 5, the tip side being a steep slope and the rear side being a gentle slope.

A recess 6 for receiving the punch 1 is formed in the die 2, and an upper edge portion of the recess 6 is a large-diameter approach portion 7.

The center of the bottom of the recess 6 is a recess 8, and an ejector pin 9 is provided at the center of the recess 6 so as to project into the recess 8.

The material 3 has a cup shape with a straight outer circumference and inner circumference, the outer diameter of which is substantially the same as the diameter of the approach portion 7 of the die 2, the inner diameter of which is substantially the same as the diameter of the punch 1, and the circumference of the inner bottom portion. An annular clearance groove 10 is formed in the.

In order to form a spline on the inner peripheral surface of the material 3 by the punch 1 and the die 2, the material 3 is first set on the approach part 7 of the die 2 as the first step (FIG. 2).
Push the punch 1 into the cup-shaped entrance of the material 3 (Fig. 3).

In the subsequent second step, while pushing the punch 1 further into the cup, the blank 3 is pushed into the recess 6 of the die 2 by the punch 1 (FIG. 4).

Then, the outer periphery of the blank 3 is squeezed to the diameter of the recess 6, and at the same time, the outer teeth 5 preliminarily form the spline tooth profile 11 on the inner peripheral surface, and the blank 3 is pressed while being squeezed.

At this time, in the punch 1, the tip end surface of the annular protrusion 4 is made of the material 3
It is stopped immediately before contacting the inner bottom surface of the annular clearance groove 10 and a surplus reservoir P is secured between the tip of the punch 1 and the inner bottom surface of the blank 3.

The excess thickness generated by the ironing action escapes to the rear of the excess thickness reservoir P and the external teeth 5, respectively.

When the punch 1 is pulled out in the subsequent third step, the outer teeth 5
The extra thickness protruding to the rear of the tooth is squeezed out simultaneously with the shaping of the spline tooth profile 11 in the returning process of the external tooth 5, and the highly accurate spline tooth profile 11 is completed on the inner peripheral surface of the material 3 (Fig. 5). ).

As described above, according to the present invention, the spline tooth profile is first preformed, and the preformed spline tooth profile is finished (finally) formed at the time of extraction, so that the spline tooth profile having a high tooth profile accuracy is formed from the cup-shaped material. A viscous coupling can be formed.

In addition, the outer teeth 4 provided on the punch 1 are formed only around the tip portion, and also have taper T.s.
Since T is added, the formation of the spline tooth profile is performed not only in the punch pushing process but also in the punching process.

Further, the contact area between the outer teeth 4 and the material is small, the flow of the excess thickness is smooth, the pressing force of the punch can be set low, and the abrasion with the outer teeth is reduced.

Furthermore, the effective tooth profile of the spline extends to the bottom as before, and since the inner circumference of the die is straight, the die shape can be simply formed and long life can be secured.

Advantageous Effects According to the present invention, it is possible to form a highly accurate spline tooth profile by one reciprocating motion of the punch, and in particular, since the finish (final) molding is performed at the time of extraction, the extra thickness is discharged to the back part, so No excess thickness is accumulated and the number of sharp corners is reduced to eliminate the cause of cracks.

Further, since the external teeth are provided only at the tip of the punch, the contact area is small, and there is no problem even if the length of the spline is long, and wear of the tip of the punch is small.

In addition, when the spline tooth profile is formed, the deformation rate is low, so the accuracy is high and the spline tooth profile with a high tooth length can be applied.

[Brief description of drawings]

The drawings show a method of molding a viscous coupling according to the present invention. FIG. 1 is an explanatory view of the apparatus, FIG. 2 and FIG.
FIG. 4 is a process explanatory diagram of the first stage, FIG. 4 is a process explanatory diagram of the second stage, FIG. 5 is a process explanatory diagram of the third stage, and FIG. 6 is an enlarged explanatory diagram of the tip portion of the punch. 1 ... punch, 2 ... die, 3 ... material, 4 ... annular projection, 5 ... outer teeth, 6 ... recess, 7 ... approaching section, 8
…… Drop-down recess, 9 …… Ejector pin, 10 …… annular clearance groove, 11 …… Spline tooth profile, T …… taper, P…
... Excessive meat pool.

Claims (1)

[Claims] 1. A punch having an annular projection formed on the peripheral edge of the tip surface and having external teeth for forming a spline tooth profile on the outer peripheral surface is pushed into a cup-shaped material having an annular clearance groove on the inner bottom surface thereof, and In a method of molding a viscous coupling in which a cup-shaped material is pushed into a die to form a spline tooth profile on the inner peripheral surface of the material, the punch is provided with spline tooth profile forming external teeth only on the tip portion of the punch, and The front and rear ends of the spline tooth profile forming external tooth are provided with guides, and the die is provided with an approach portion with a wider diameter on the punch pushing side. Further, the outer diameter of the material is at least equal to or less than the diameter of the approach portion of the die. First, in the first step, the punch is pushed into the cup-shaped inner entrance of the material set in the approach section, and in the subsequent second step, the punch is further closed. The material is pushed into the die by pushing it into the die while pushing it into the inner part of the cup shape, and it is stopped just before the tip of the annular projection of the punch comes into contact with the inner bottom surface of the annular relief groove of the material. A method for forming a viscous coupling, wherein a spline tooth profile is formed on the inner peripheral surface of the cup-shaped material by pulling out a punch.