JPH0360839A - Manufacture of outer race of constant velocity joint - Google Patents

Abstract

PURPOSE:To manufacture the outer race for a constant velocity joint excellent in dimensional precision through forging by fitting a punch loosely to one of prepared holes of a preformed body, ironing the outer peripheral surface and forcing the punch into the other prepare hole under that state to be formed. CONSTITUTION:A cylindrical billet 22 is upset to form a cup part 12 and an axial part 14. Then, the punches are forced into the cup part 12 and the axial part 14 from both end sides facing each other in the axial direction to form the preformed body 24 having a 1st prepared hole 26 on the cup part 12 and a 2nd prepared hole 28 on the axial part 14. In that case, the whole peripheral length of the 1st prepared hole 26 is formed to be a little larger than the finish dimension of the track groove and the 2nd prepared hole 28 coaxial to the 1st prepared hole is formed to be a little smaller than the finish diameter of the serration part. Then, the outer peripheral surface of the preformed body 24 is ironed and the track groove is formed and finished after the outer peripheral surface of the punch fitted loosely to the 1st prepared hole 26. Further, as this punch is pressed, this punch and the punch for working the serration are displaced relatively and the serration part 18 is forced into the 2nd prepared hole 28 and formed.

Description

Detailed Description of the Invention [Industrial Application Field] 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. Regarding equipment.

[Prior Art] In the past, the outer ring of this type of constant velocity jaw joint was generally one in which one end of the cup body was open and the driven wheel was integrally molded on the other end of the cup body. Types that connect via serrations provided on the body have come to be 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 shaft of the cup body. The following steps are required.

Up to now, track groove molding and serration part molding have been carried out separately, and the methods disclosed in Japanese Patent Publications No. 4G-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. 5848258 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 the constant velocity joint as described above, the uniformity of the track grooves and the serrations becomes a problem.

In order to improve homogeneity, first, the trunk groove is finished when the outer ring is forged, and then the serrations are formed by broaching, but the inner diameter must be finished by machining during the broaching process. Therefore, the inconvenience of increasing the number of steps could not be avoided.

The present invention has been made in view of the above points, and provides a constant velocity joint outer ring that enables forming a constant velocity joint outer ring with high precision in terms of uniformity of track grooves and serrations only by forging. The purpose 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. This is a method of manufacturing by forging, which includes the 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 trunk groove. a second step of molding a preformed body having a first prepared hole whose total circumference is slightly larger than the finished dimension, and a second prepared hole whose total circumference is smaller than the finished diameter of the serration portion coaxial with the first prepared hole; The first ironing process is applied from the outer peripheral surface of the preform.
a third step of finishing forming a track groove to follow the outer peripheral surface of the punch that is loosely fitted into the pilot hole, and inserting the punch and the punch for serration processing while maintaining the state in which the punch is press-fitted into the preformed body. The method is characterized by comprising a fourth step of press-forming the serration portion into the second pilot hole by relatively displacing the serration portion.

Further, the manufacturing apparatus of the present invention is a constant velocity joint manufacturing apparatus for forming 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 of the preform, comprising: an inner punch for machining the serrations, an outer punch for track groove forming that coaxially and slidably fits onto the inner punch, and an outer punch to allow relative displacement between the outer punch and the inner punch. a supporting cushion means; a die disposed opposite to the outer punch for applying ironing to the outer circumferential surface of the preform and pressing the inner circumferential surface of the preform against the outer punch to shape the track groove; A block body disposed at a predetermined position of the die and abuts against the preformed body after forming the track groove to restrain it against the outer punch and displaces the outer punch relative to the inner bunch to project the tip of the inch punch. It is characterized by comprising the following.

[Function] First, by squeezing the preform using a die, a track groove is formed in the second (prepared hole) so as to follow the outer peripheral surface of the outer punch, and then the abutment block is pressed against the outer punch of the preform. By pressing against the cushion means while maintaining the restrained state, the tip of the inner punch protrudes and a serration portion is formed in the second pilot hole.

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

FIG. 1 is a longitudinal sectional view of an outer ring 10 of a constant velocity joint to be manufactured, and FIG. 2 is a sectional view taken along the line ■--■ in FIG. This outer ring 10 has a cup B12 that is open at one end.
and a cylindrical shaft portion 14 on the side opposite to the opening side of the cup portion 12 are integrally formed by forging.

Three track grooves 16a to 16c are provided on the inner periphery of the cup portion 12 to extend in the axial direction and receive the trunnions.
is formed. On the other hand, a serration portion 18 is formed on the inner periphery of the shaft portion 14, and a shaft on the driven side meshes with this serration portion 18. The track grooves 16a to 16c of the cup portion 12 and the serrations 1 of the shaft portion 14
18 has the same central axis. Note that a step portion 20 that expands toward the cup portion 12 is formed at a portion where the inner circumferential surface of the shaft B14 faces the cup portion 12, and this step portion 2o has grooves sealed in the track grooves 16a to 16c. A cap (not shown) is attached to prevent grease from leaking.

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

First, in the first forging process, a cylindrical billet 22 (see Fig. 3a) is subjected to upsetting to form a billet 2.
2a (see Fig. 3) After forming the billet 22b (see No. 3 Zc), the punches are pushed into the billet 22b from opposite ends in the axial direction to form a cup shape. A preformed integral body 24 is formed (see FIG. 3d). The cup portion 12 of the preform 24 has a first prepared hole 26 having a shape similar to the track grooves 16a to 16C, and the shaft portion 14 has a second prepared hole 28 in which the serration portion 18 is not formed. The first prepared hole 26 and the second prepared hole 28 are in an unreachable state. In this case, in order to form the track grooves 16a to 16C to follow the outer peripheral surface of the punch by ironing the first prepared hole 26, as will be described later, the finished dimensions of the track grooves 16a to 16c are completely 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. 3e).
. In this step, from the second prepared hole 2B side to the first prepared hole 26
Direct it to the 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 punching out burrs, the subsequent hole diameter tends to expand in the punching direction. However, in order to form the serrations, it is not preferable for the second prepared holes 28 to have such a difference in diameter. Therefore, by punching from the second prepared hole 28 side to the first prepared hole 26, the diameter of the portion corresponding to the stepped portion 20 to which the cap for preventing grease leakage is attached is enlarged. This will eliminate the inconvenience.

The preform 24 obtained in this way is attached to the track 1116
A to 16c and the serration portion 18 are formed (see FIG. 3f) and the product is sent to a second forging process.

The manufacturing equipment used in this second step is shown in FIG.

This manufacturing apparatus 40 includes an inner punch 42 for processing serrations, an outer punch 44 for forming track grooves that is slidably fitted onto the inner punch 42, a cushion means 46 for supporting the outer punch 44, and the outer punch 44. It includes a die 50 and an abutment block 51 that are attached to the press ram 48 of the press machine so as to face the press ram 44 and move up and down.

First, the inner punch 42 and the outer punch 44 are held by a punch holder 53 and are erected so as to be oriented in the vertical direction. A serration processing portion 54 is provided at the tip of the inner punch 42, and the serration processing portion 5
4 includes teeth that plastically deform the inner circumferential surface of the preform 24 to form the serrations 18 when it is pushed into the second prepared hole 28 of the preform 24 .

On the other hand, as shown in FIG. 5, the outer punch 44 extends along the track groove 1 of the outer ring 10 along its axial direction.
Three prismatic sections 56a to 56 corresponding to 6a to 16C
c is formed as a bulge. The clearance between the outer punch 44 and the inner peripheral surface of the preform 24 is
4 is not tilted and its positioning accuracy is not deteriorated, on the other hand,
In order to prevent light press-fitting into the inner circumferential surface of the preform 24, the thickness is preferably about 0.2 to 0.5 mm, taking into account ease of insertion.

Supporting such an outer punch 44, the outer punch 4
In this embodiment, a pair of hydraulic cylinders 5g and 58 are used as the cushion means 46 that allows relative displacement such that the tip of the inner punch 42 protrudes when the inner punch 4 is moved backward. In this case, before machining, the piston rod 58a of the hydraulic cylinder 58 protrudes from the punch holder 53 to ensure a sliding stroke for the outer punch 44, so that the outer punch 44 is supported in a floating manner.

Next, the die 50 attached to the press ram 48 has a tapered surface 60 for guiding and a preform 24 on the inner circumference.
A straining surface 62 having a smaller diameter than the outer diameter of the iron is formed.

Further, in the press ram 48, the abutting block 51 disposed above the die 50 in the drawing is a
When the press ram 48 descends against the press ram 4, the press ram 48 is arranged so as to come into contact with the press ram 48 at a predetermined position.

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 punch 44.

At this time, the serration processing part 5 at the tip of the inner punch 42
4 faces the second pilot hole 28 of the preform 24.

Then, the press ram 48 of the press machine is lowered, and the die 50 attached to this press ram 48 produces a preformed body 2.
4 to form track grooves 16a to 16C.

That is, the tapered surface 60 on the inner circumference of the die 50 comes into contact with the preform 24, and after the die 50 descends while being guided along this tapered surface 60, the inner circumference of the die 50 is pressed against the ironing surface 6.
2 comes into contact with the outer peripheral surface of the preformed body 24. On the other hand, the preformed body 24 is in a state in which the outer punch 44 is loosely fitted into the first pilot hole 26, and in this state, in the process of further lowering the press ram 48, the die 50 is inserted into the inner circumferential ironing surface 6.
In step 2, ironing is performed on the outer circumferential surface of the tNTft feature 24 in advance.

In this case, as shown in FIG. 6, the preform 24 is stretched, and its inner circumferential surface is pressed against the outer circumferential surface of the outer punch 44, causing plastic deformation so that the flesh of the inner circumferential surface is brought into close contact. As a result, the preformed body 24 is formed into the outer ring 10 in which the track grooves 16a to 16C are precisely formed on the inner peripheral surface thereof.

Next, the press ram 48 further descends and the inner punch 42 forms the serrations 18.

That is, as the press ram 48 descends, the abutting block 51 comes into contact with the preform 24.

The abutting block 51 presses the outer punch 44 while restraining the preform 24 in close contact with the outer punch 44 and displaces it against the hydraulic cylinder 58. As a result, when considering the preform 24 to be processed as a reference, the tip of the inner punch 42 protrudes into the second prepared hole 28 of the preform 24, which is a relative displacement, and the peripheral surface of the second hole is Serration portions 18 are formed.

As described above, in the outer ring IO, first, the outer peripheral surface of the preform 24 is squeezed to form the track grooves 16a to 16c, and the state in which the preform 24 is press-fitted into the outer punch 44 is inserted into the abutting block 51. Since the serrations 18 are formed while maintaining the outer punch 44, the outer punch 44 serves as a reference when lowering the serrations 18, and the track grooves 16a to 1 formed following the outer punch 44
The accuracy of the comradeship between 6C and the serration portion 18 is improved.

Further, when positioning the preform 24 on the outer punch 44, the tip of the inner punch 42 is attached to the outer punch 44.
In addition, since there is sufficient clearance between the outer punch 44 and the preform 24, the positioning of the preform 24 is good. Even if the preformed body 24 has formed the track grooves 16a to 16C, it is firmly restrained by the outer punch 44 and the abutment block 51, so that the serrations 18 and the track grooves 16a
Comradeship with 16G is ensured.

[Effects of the Invention] As explained above, according to the present invention, the track groove is first formed and the serrations are formed in accordance with the track groove, so that the track groove of the outer ring of the constant velocity joint is The comradeship of the serrations can be ensured with good accuracy. Furthermore, since both can be formed at once using only the forging process, it is suitable for mass production of constant velocity joint outer rings, and has the effect of contributing to 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.
FIG. 3 is a cross-sectional view of the manufacturing apparatus during processing. 10... Outer ring 12... Cup portion 14
... Shaft portion 16 a - 16c ... Track groove 18 ... Serration II 22 ... Billet 24 ... Preformed body 26 ... First pilot hole 28
...Second pilot hole 30...Burr 40...Manufacturing device 42...Inner punch 44...Outer punch 46...Pacushion means 48...
Press ram 50...Die 51...Abutment block FIG, 6 52 Fl(

Claims (3)

[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 of forming a first prepared hole with a total circumference slightly larger than the finished dimension of the track groove, and a first prepared hole with a total circumference slightly larger than the finished dimension of the track groove, and a first prepared hole with a serration portion coaxial with this hole. A second step of forming a preform having a second pilot hole smaller than the finished diameter, and a first step of ironing the outer peripheral surface of the preform.
A third step is to finish form a track groove to follow the outer circumferential surface of a punch that is loosely fitted into the prepared hole, and a third step in which the punch and a punch for serration processing are formed while maintaining the state in which the punch is press-fitted into the preform. A method for manufacturing a constant velocity joint outer ring, comprising: a fourth step of press-forming a serration portion into a second prepared hole by relatively displacing the serration portion. (2) The manufacturing method according to claim 1, characterized in that the burr separating the first prepared hole and the second prepared hole is punched out using a punch, with the burr separating the first prepared hole and the second prepared hole directed from the second prepared hole to the first prepared hole. A method of manufacturing a constant velocity joint outer ring. (3) A constant velocity joint manufacturing device that forms 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 processed at the tip part. an inner punch, an outer punch for forming a track groove coaxially and slidably fitted onto the inner punch, and a cushion means for supporting the outer punch to allow relative displacement between the outer punch and the inner punch; a die disposed opposite the outer punch for ironing from the outer peripheral surface of the preform and pressing the inner circumferential surface of the preform against the outer punch to mold the track groove; and a die disposed at a predetermined position of the die. a block body which is provided and comes into contact with the preformed body after track groove forming to place it under restraint with respect to the outer punch, and displaces the outer punch relative to the inner punch to project the tip of the inner punch; Characteristic constant velocity joint manufacturing equipment.