JPH0360838A - Manufacture of outer race of constant velocity joint and its device - Google Patents

Abstract

PURPOSE:To manufacture the outer for a constant velocity joint having a track groove and a serration part which are excellent in concentricity by forcing punches respectively into prepared holes formed in a cup part and an axial part of a cylindrical stock and ironing its outer peripheral surfaces. CONSTITUTION:A cylindrical billet 22 is upset to a billet 22b having a cup part and an axial part. Then, punches are forced in respectively and a performed body 24 having a 1st prepared hole 26 a little larger in the whole peripheral length than the finish dimension of the track groove in the cup part 12 and a 2nd prepared hole 28 smaller than the finish diameter of the serration part 18 coaxial to an axial part 14 on the axial part 14 is formed. Then, after burrs 30 between both prepared holes 26, 28 are removed by the punches, the punch is forced into the 2nd prepared hole 28 to form the serration part 18. On one hand, the outer peripheral surface of the preformed body 24 is ironed and a track groove is formed on the inner surface of the cup part 12 after the outer peripheral surface of the punch fitted loosely to the 1st prepared hole 26. Thus, the outer race 10 a constant velocity joint having a track groove and a serration for part 18 which are excellent in concentricity precision is formed by forging only.

Description

Detailed Description of the Invention [Field of Industrial Application] The present invention relates to a method for manufacturing a constant velocity joint outer ring having a track groove on the inner periphery of the cup portion and a serration portion on the inner periphery of the shaft portion by forging, and the method thereof. Regarding manufacturing equipment.

[Prior Art] In the past, the outer ring of this type of constant velocity joint generally had one end open and a driven shaft integrally formed at the other end of the cup body. Outer rings of constant velocity joints of a type that are connected via serrations provided on a cup body have been manufactured.

For the outer ring of such a constant velocity joint, there is a process for forming a plurality of track grooves extending in the axial direction on the circumferential surface of the cup body, and a process for forming a serration part on the inner diameter of the shaft part of the cup body. A process is required for this purpose.

Up to now, the formation of track grooves and the formation of serrations have been carried out separately, and the methods disclosed in Japanese Patent Publication No. 48-4809 and No. 48-19806 are methods for forming track grooves. Furthermore, as a method for forming the serration portion, a method disclosed in Japanese Patent Publication No. 58-48258 is known.

[Problems to be Solved by the Invention] When the track grooves and the serrations are individually molded in the process of manufacturing the outer ring of such a constant velocity joint, the compatibility of the track grooves and the serrations becomes a problem.

In order to improve coreability, first finish the track grooves when forming the outer ring by forging, and then form the serrations by broaching, but it is necessary to finish the inner diameter by machining during broaching. Therefore, the inconvenience of increasing the number of steps was unavoidable.

The present invention has been made in view of these points, and provides a constant-velocity joint outer ring that improves the accuracy of the sameness of the track groove and the serrations, and also allows both to be formed simultaneously by just forging. The purpose of the present invention is to provide a manufacturing method and a manufacturing device.

[Means for Solving the Problems] In order to solve the above problems, the manufacturing method of the present invention provides a constant velocity joint outer ring having an axial track groove on the inner periphery of the cup portion and an axial serration portion on the inner periphery of the shaft portion. A method for manufacturing by forging, which includes: a first step of providing a cup part and a shaft part in a cylindrical material, and punching the inner periphery of the cup part and the shaft part facing each other to form a finished track groove. The first one has a slightly larger total circumference.
a second step of molding a preformed body having a pilot hole and a second pilot hole coaxial with the preform having a diameter smaller than the finished diameter of the serration section; and pushing a punch into the second pilot hole to form the serration section. A third step of forming, a fourth step of ironing the outer circumferential surface of the preform, and a fifth step of forming a track groove to follow the outer circumferential surface of the punch that loosely fits into the first prepared hole. It is characterized by consisting of.

Further, the manufacturing apparatus of the present invention is a constant velocity joint outer ring manufacturing apparatus that compositely molds an axial track groove on the inner periphery of the cup part and an axial serration part on the inner periphery of the shaft part on the preform, An inner punch for processing a serration part at the tip, an outer punch for forming a track groove that is coaxially fitted onto the inner punch, and an ironing process is applied to the outer circumferential surface of the preform to bring it into close contact with the outer punch to form a track groove. It is characterized by comprising a die for copy forming.

[Operation: First, the inner punch fits into the second pilot hole of the preform to form the serrations, and then the track groove is formed in the preform by the cooperation of the die and the outer punch that fits into the first pilot hole. is formed.

[Example] Next, an example of a method for manufacturing a constant velocity joint outer ring and an apparatus for manufacturing the same according to the present invention will be described in detail below with reference to the accompanying drawings.

FIG. 1 is a longitudinal cross-sectional view of the outer ring lO of the constant velocity joint to be manufactured, and FIG. 2 is a cross-sectional view taken along the line ■-■ in FIG. 1. This outer ring 10 has a cup portion 12 that is open at one end.
and a cylindrical shaft part 14 on the opposite side to the opening side of the cup part 12, and the cup part 12 and the shaft part 1
4 is one that is integrally formed by forging. Three track grooves 16a to 16C are formed on the inner periphery of the cup portion 12 to extend in the axial direction and receive the trunnions. On the other hand, a serration portion 18 is formed on the inner circumference of the shaft portion 14, and this serration portion 1
8 is engaged with the shaft on the driven side.

The track grooves 16a to 16c of the cup portion 12 and the serration portion 18 of the shaft portion 14 have the same central axis. Note that a step portion 20 that expands toward the cup portion 12 is formed at a portion of the inner circumferential surface of the shaft portion 14 facing the cup portion 12, and this step portion 20 has grooves sealed in the track grooves 16a to 16C. A cap (not shown) is attached to the cap to prevent the grease from leaking.

Next, FIG. 3 shows the shapes of molded products corresponding to each process constituting the method for manufacturing such an outer ring 10.

First, in the first forging process, the cylindrical billet 22 (see Fig. 3C) is subjected to upsetting to form the billet 2.
2a (see Figure 3)
22b (See Figure 3 C) After tossing, this billet) 22b
A punch is pushed in from both sides in the axial direction facing each other to form a cup-shaped preform 24 (Fig. 3C).
reference). In this process, the preform 24 is roughly formed into the shape of the outer ring 10, which is the final product. That is, the cup portion 12 is formed with a first prepared hole 26 having a shape similar to the track grooves 16a to 16C, and the shaft portion 14 is formed with a second prepared hole 28 in which the serration portion is not formed. Therefore, the first prepared hole 26 and the second prepared hole 28 are in an unreachable state. In this case, the first prepared hole 26 is ironed as described later, and in order to form the track grooves 16a to 16C to follow the outer circumferential surface of the punch, all of the finished dimensions of the track grooves 16a to 16G are The first prepared hole 26 is formed so that its total circumferential length is slightly larger than its circumferential length. Further, the second prepared hole 28 is formed so that its inner diameter is smaller than the finished diameter of the serration portion 18 in order to press the punch and form the serration portion 18 .

Next, in the preform 24, the intermediate burr 30 between the cup portion 12 and the shaft portion 14 is punched out (see FIG. 3C).
. In this step, from the side of the first pilot hole 28 to the second pilot hole 28,
Direct it to the 6 side and punch it out. In this step, the reason why the burr 30 is punched out in the above direction is as follows. That is, in general, when a burr is punched out, the diameter of the subsequent hole tends to increase in the punching direction. However, in order to form the serrations,
It is not preferable that the second prepared hole 28 has such a difference in hole diameter. Therefore, from the side of the second pilot hole 28, the first pilot hole 26
By punching it out, the diameter of the portion corresponding to the stepped portion 20 to which the cap for preventing grease leakage is attached is enlarged, so that the above-mentioned inconvenience is resolved.

The preformed body 24 thus obtained is sent to a second forging process in which the track grooves 16a to 16c and the serrations 18 are formed (see FIG. 3).

The manufacturing equipment used in this process is shown in FIG.

This manufacturing device 40 includes an inner bunch 42 for serration processing, an outer bunch 44 for forming track grooves that fits around the inner punch 42, and a press ram 4 of a press machine.
6 and a die 48 that moves up and down.

First, the inner punch 42 and the outer bunch 44 are held by the punch holder 50 and are oriented vertically. A serration processing part 52 is provided at the tip of the inner punch 42, and when this serration processing part 52 is pushed into the second pilot hole 28 of the preform 24, the inner peripheral surface is plastically deformed, and the serration processing part 1
8. Such an inner punch 42 is lightly press-fitted into the outer bunch 44.

On the other hand, as shown in FIG. 5, the outer bunch 44 extends along the track groove 1 of the outer ring IO along its axial direction.
Three square column parts 54a to 54 corresponding to 6a to 16c
c is formed as a bulge. Such a clearance between the outer bunch 44 and the inner circumferential surface of the preform 24 prevents the preform 24 from tilting and deteriorating its positioning accuracy. 0.2~Q in consideration of ease of insertion to avoid light press-fitting to the circumferential surface.
, approximately 5 mm is suitable.

Next, a tapered surface 5 for guiding is provided on the inner circumference of the die 48.
6, and an ironing surface 58 having a smaller diameter than the outer diameter of the preform 24.
is formed.

The details of the second step performed using the manufacturing apparatus 40 configured as described above will be explained in relation to the operation of the manufacturing apparatus 40.

First, as shown in FIG. 4, the preform 24 is positioned so as to cover the outer bunch 44. At this time, the serrated portion 52 at the tip of the inner bunch 42 faces the second pilot hole 28 of the preform 24.

Then, the press ram 46 of the press machine is lowered, and the die 48 attached to this press ram 46 produces a preformed body 2.
4, track grooves 16a to 16c and serrations 18
to form.

That is, when the tapered surface 56 on the inner circumference of the die 48 comes into contact with the preform 24 and the die 48 descends while being guided along the tapered surface 56, the preform 24 is also displaced downward accordingly. As a result, the serration processing portion 52 of the inner punch 42 is inserted into the second pilot hole 28 of the preform 24.
As a result, plastic deformation occurs on the inner circumferential surface of the second prepared hole 28, and the serration portion 18 is formed.

Then, when the press ram 46 descends, the ironing surface 58 on the inner circumference of the die 48 comes into contact with the outer circumferential surface of the preform 24, while the preform 24 is loosely fitted into the outer bunch 44. , further downward displacement of the preform 24 is restricted. When the press ram 46 further descends under this condition, the die 48 irons the outer peripheral surface of the preform 24 with the ironing surface 58 on its inner periphery.

In this case, the preform 24 is stretched as shown in FIG.
4 is pressed against the outer circumferential surface of the inner circumferential surface, plastic deformation occurs such that the flesh of the inner circumferential surface comes into close contact with the outer circumferential surface of the pre-formed body 24. As a result, the pre-formed body 24 becomes an outer ring having track grooves 16a to 16c formed with precision on its inner circumferential surface. It will be molded into IO. By going through the above processing steps, the serrations 18 and the track grooves 16 to 16c can be formed at once with one stroke of the press ram 46.

Furthermore, in the outer ring 10 formed in this manner, the inner punch 42 for forming the serration portion 18 and the outer bunch 44 for forming the tracks a16a to 16c are integrally formed, so that their compatibility is also the same.

Next, another embodiment of the manufacturing apparatus will be described based on FIG. 7. In this case, the same components as in the first embodiment will be given the same reference numerals and detailed explanations thereof will be omitted.

In the manufacturing apparatus 60 according to the second embodiment, the die 48 is fixed downward, and the inner punch 42 and the outer bunch 4
4 is fixed to the press ram 46. The outer bunch 44 fitted onto the inner punch 42 is connected to the inner punch 42.
The structure is such that it can slide freely against the surface. In particular, the outer bunch 44 is resiliently biased by a coil spring 64 interposed between the punch holder 62 and the inner punch 42,
Normally, the serration processing part 52 at the tip of the inner punch 42
is in a state of being drawn inside the outer punch 44.

In the manufacturing apparatus 60 as described above, first, the preform 24
is set against the die 48, and press ram 4 of the press machine.
6 is lowered, the preform 24 is positioned by the outer punch 44 and die 48.

After that, when the press ram 46 further descends, the coil spring 64 is compressed, and the serration processing part 52 of the inner punch 42 is pushed into the second prepared hole 28 of the preform 24 so as to protrude from the outer punch 44. Serration portions 18 are formed.

Thereafter, when the press ram 46 descends, the track groove 16 is ironed by the die 48, as in the first embodiment.
a to 16C are formed.

According to this second embodiment, the preform 2 before processing
4 has a good positioning accuracy, which has the advantage of further improving the compatibility between the serrations 18 and the track grooves 16a to 16c.

[Effects of the Invention] As explained above, according to the present invention, the track groove and the serration portion of the outer ring of a constant velocity joint can be formed with good precision so that they have comradeship, and both can be formed simply by the forging process. Since it can be molded all at once, it has the effect of further improving productivity.

[Brief explanation of drawings]

FIG. 1 is a longitudinal sectional view of the outer ring of a constant velocity joint, FIG. 2 is a sectional view of the outer ring in FIG. 4 is a cross-sectional view of the manufacturing apparatus used in the manufacturing method, FIG. 5 is a cross-sectional view taken along the line ■-V in FIG. 4, and FIG. 6 is a process diagram according to the example.
A cross-sectional view of the manufacturing apparatus during processing, FIG. 7 is a cross-sectional view of the manufacturing apparatus according to another embodiment. lO...Outer ring 14...Shaft portion 16a-16C...Track structure 18...Serration portion 24...Preformed body 28...Second prepared hole 40...Manufacturing device 44...・Outer punch 48...Die 12...Cup part 22...Billet 26...First pilot hole 30...Burr 42...Inner punch 46...Press ram 1G, 3 (d) (e ) (f) FIG, 6

Claims (4)

[Claims] (1) A method of manufacturing a constant velocity joint outer ring having an axial track groove on the inner periphery of the cup part and an axial serration part on the inner periphery of the shaft part by forging, in which the cup part and the shaft part are formed on a cylindrical material. A first step in which the total circumference length is slightly larger than the finished dimension of the track groove is pushed by opposing punches to the inner periphery of the cup portion and the shaft portion, respectively.
a second step of molding a preformed body having a pilot hole and a second pilot hole coaxial with the preform having a diameter smaller than the finished diameter of the serration section; and pushing a punch into the second pilot hole to form the serration section. A third step of forming, a fourth step of ironing the outer circumferential surface of the preform, and a fifth step of forming a track groove to follow the outer circumferential surface of the punch that loosely fits into the first prepared hole. A method for manufacturing a constant velocity joint outer ring, comprising: (2) In the manufacturing method according to claim 1, the first step includes:
A method for manufacturing a constant velocity joint outer ring, comprising the step of punching out a burr separating a first pilot hole and a second pilot hole from the second pilot hole toward the first pilot hole using a punch. (3) A constant velocity joint outer ring manufacturing device that compositely molds an axial track groove on the inner periphery of the cup part and an axial serration part on the inner periphery of the shaft part on a preform, the serration part being formed at the tip part. An inner punch to be processed, an outer punch for forming a track groove that is coaxially fitted onto the inner punch, and a die that applies ironing to the outer peripheral surface of the preform and brings it into close contact with the outer punch to mold the track groove. A constant velocity joint outer ring manufacturing device characterized by: (4) In the manufacturing apparatus according to claim 3, the outer punch is slidably supported in a floating manner with respect to the inner punch via an elastic member, so that the tip of the inner punch protrudes from the outer punch before ironing with the die. A manufacturing device characterized in that it is configured as follows.