WO2018070758A1

WO2018070758A1 - Method for manufacturing universal joint using pipe

Info

Publication number: WO2018070758A1
Application number: PCT/KR2017/011131
Authority: WO
Inventors: 이병화
Original assignee: 이양화
Priority date: 2016-10-11
Filing date: 2017-10-11
Publication date: 2018-04-19

Abstract

The purpose of the present invention is to provide a method for manufacturing a universal joint using a pipe, wherein a shaft joint having a yoke formed integrally therewith and a pipe joint are manufactured by cutting a pipe into a material having a predetermined length, forming the material, pressing the material, and then processing the material, thereby providing advantageous effects of manufacturing cost reduction, productivity improvement, and product weight decrease while guaranteeing durability. Particularly, a pipe joint is manufactured by a material preparing step of cutting a pipe into a predetermined length, thereby preparing a material; a shaft forming step of forming the outer portion of a shaft forming portion of the material, excluding a head forming portion, by a forming machine such that, by reducing the outer diameter thereof, a shaft is formed; an incising step of forming a splitting groove on the head forming portion, which has not been reduced, in the axial direction such that the same is bifurcated; a yoke forming step of pressing the incised head forming portion such that a pair of yokes are formed on the head so as to face each other; a pin hole forming step of forming a pin hole in the yoke; a material preparing step of manufacturing a shaft joint through a spline shaft forming step of forming a spline shaft on the outer surface of the reduced hollow shaft and cutting the pipe into a predetermined length, thereby preparing a material; a tube forming step of forming the outer portion of a tube forming portion of the material, excluding a head forming portion, by the forming machine such that the outer diameter thereof is reduced; an incising step of forming a splitting groove on the head forming portion, which has not been reduced, in the axial direction such that the same is bifurcated; a yoke forming step of pressing the incised head forming portion such that a pair of yokes are formed on the head so as to face each other; a pin hole forming step of forming a pin hole in the yoke; and a spline boss forming step of forming a spline boss on the inner surface of the reduced hollow tube.

Description

Universal joint manufacturing method using pipe

The present invention relates to a method for manufacturing a universal joint using a pipe applied to a steering device for arbitrarily manipulating the traveling direction of a vehicle. More specifically, the manufacture of a shaft joint and a pipe joint in which a yoke is integrally cuts the pipe to a predetermined length. It is to provide a universal joint manufacturing method using a pipe that can satisfy the durability while providing the effect of reducing the manufacturing cost, improving productivity, and reducing the weight of the product by forming a material by forming and pressing after processing. .

In general, a vehicle is provided with a steering device for the driver to arbitrarily change the direction of travel of the vehicle. The steering device is installed in front of the driver's seat, and the steering wheel for changing the driving direction of the vehicle by the driver's operation, the steering column is installed in the lower portion of the steering wheel, and converts the rotational movement of the steering wheel into a straight motion and At the same time includes a steering gear box for changing the direction of the tire by increasing the steering force, and a universal joint assembly for transmitting the rotational force transmitted to the steering column to the steering gear box.

The universal joint is composed of a shaft joint and a pipe joint that transmits rotational force to the shaft joint, wherein the spline formed in the concave-convex shape on the outer surface of the shaft joint is fitted to the spline formed in the concave-convex shape on the inner surface of the pipe joint to transmit the rotational force in the axial direction. It is configured to move to.

Yoke is configured at the shaft joint and pipe joint end, the yoke configured at the shaft joint is connected to the steering column, and the yoke configured at the pipe joint is connected to the gearbox.

As the prior art related to the universal joint, 'Universal universal joint for automobile and its manufacturing method' of Korean Patent Application Publication No. 10-2006-0116099 (Nov. 14, 2006) is provided. A shaft joint forming step of inserting a material having a length and an outer diameter into a die serving as a mold and pressing plastically deforming with a punch to integrally form the shaft portion and the yoke portion; A hole processing step of processing a connection hole to connect another joint such as a spider to the yoke portion of the shaft joint; Shaping a gear on an outer surface of the shaft portion; A pipe joint molding step of inserting a material having a predetermined length and outer diameter into a die serving as a mold and pressing the punch with plastic to deform the pipe part and the yoke part into which the shaft is inserted; A hole processing step of processing a connection hole to connect another joint such as a spider to the yoke portion of the formed pipe joint; Shaping a spline corresponding to a gear of a shaft part inside the molded pipe part; And an assembly process of inserting the shaft portions of the manufactured shaft joints into the pipe portions of the pipe joints so as to have the shape of the completed universal joints.

Another prior art is provided in the 'Yok manufacturing method' of the Republic of Korea Patent Publication (B1) 10-1322363 (2013.10.28.), The configuration of the raw material of the round bar by tube extrusion molding knuckle (knuckle) A first step of processing the yoke forming member to form a portion and a shaft portion; A second step of punching a knuckle portion of the yoke forming member processed in the first step to process a plate-like tension portion on each side of the knuckle portion; A third step of piercing processing and punching a connection hole in the inside of the tension portion so that the inside of the shaft portion penetrates to the knuckle portion in which the tension portion is processed in the second step; A fourth step of performing a first bending process so that the tensioned portion in which the connection hole is processed in the third process is bent upward with respect to the knuckle portion; A fifth step of performing a second bending process such that the first bent tension portion in the fourth process is bent perpendicularly to the knuckle portion; The sixth process of spline-processing the inner peripheral surface of the shaft part pierced by the 3rd process is included.

As another prior art, Korean Patent Application Publication (B1) 10-1632702 (2016.06.22.) Provides a method of manufacturing a pipe joint for a vehicle steering device, and its configuration is supplied from one side of the forming machine. Cutting the material to obtain a cutting material, and supplying the cut material to the center groove forming die and pressurized with a punch to form a center groove on one side of the material, and the first rear extrusion molding die The first rear extrusion process to move the die pin forward to form inner diameter holes and pipes on one side of the material, and to place the material in front of the second rear extrusion die, and then move the die pin forward. Second rear extrusion molding process to make the inner diameter hole longer, and the yoke preforming process of placing the material in front of the yoke preliminary die and pressing with a punch; The yoke forming process of placing the material in front of the yoke forming die through a conveying device and then pressing the yoke forming punch to form a yoke having a connection groove, and simultaneously forming an inner diameter hole with a die pin; In manufacturing a pipe joint for a vehicle steering apparatus comprising a spline molding process for forming a spline in a pipe, the center groove forming process, the first rear extrusion process, the second rear extrusion process, the yoke preforming process, and the yoke The molding process and the spline molding process are cold forged in the forming machine, but the yoke preforming process places the material formed in the second rear extrusion process in front of the yoke preforming die and presses it with a punch, On the opposite side of the formed material is larger than the outer diameter of the material, the preliminary yoke formed with a guide groove in the center is molded, and the yoke forming process is The yoke is pressed with a yoke forming die to form a yoke having a connection groove in the preliminary yoke, and the spline forming process inserts the material formed in the yoke forming process into a splice and presses a spline punch to form an uneven shape on the pipe. Of splines.

The prior art as described above is made of a raw material is made of a round bar, is formed by the process of straightening and bending the rod-like material in the forging process to form the yoke portion, and also in the case of pipe joints, extrusion through a hole through the center It should be formed by the method, the manufacturing process is complicated, it was difficult to improve the productivity.

In the case of the shaft joint, it was difficult to provide light weight by forming a spline shaft on the outside of the rod-shaped material, and it was difficult to contribute to reducing the weight of parts for improving fuel efficiency in the automobile industry.

The present inventors have developed the present invention to solve all the problems according to the conventional method of manufacturing a universal joint.

That is, in the present invention, unlike the conventional rod-like raw material, the shaft is formed by forming a shaft and a tube in the shaft joint and the pipe joint using the pipe as the raw material, and manufacturing is performed by pressing and machining the yoke portion. The technical problem of the invention is to provide a method of manufacturing a universal joint using a pipe that can significantly reduce the weight by providing the inside of the shaft joint in a hollow state. The present invention has been completed.

In the present invention, in the manufacture of a universal joint consisting of a combination of a shaft joint and a pipe joint integrally formed with the first yoke; The shaft joint, a material preparation step of preparing a material by cutting the pipe to a predetermined length; Shaft forming step of forming a shaft by reducing the outer diameter by forming the outside of the shaft shaping portion except the head shaping portion in the material with a forming machine; An incision step of dividing and forming a dividing groove in the axial direction in the unmolded head portion; A yoke forming step of forming a pair of yokes facing the head by pressing the cut head forming part; A pinhole forming step of forming a pinhole in the yoke; It is characterized in that it is produced by a spline shaft forming step of forming a spline shaft on the reduced outer shaft surface.

In the manufacture of a universal joint consisting of a combination of a shaft joint and a pipe joint integrally formed with a second yoke; The shaft joint, a material preparation step of preparing a material by cutting the pipe to a predetermined length; Shaft forming step of forming a shaft by reducing the outer diameter by forming the outside of the shaft shaping portion except the head shaping portion in the material with a forming machine; A pre-yoke molding step of forming a pre-yoke through a pressing method (forging) in which a press-formed press is pressed into the head-forming part after inserting the unmolded head-forming part into a mold; A cutting step for forming a yoke for cutting the connected part except the yoke part in a rectangular cylindrical shape having an upper opening formed by the pre-yoke forming step; A pinhole forming step of forming a pinhole in the yoke; It is characterized in that it is produced by a spline shaft forming step of forming a spline shaft on the reduced outer shaft surface.

In manufacturing a universal joint consisting of a combination of a shaft joint and a pipe joint integrally formed with a third yoke; The pipe joint, a material preparation step of preparing a material by cutting the pipe to a predetermined length; A tube forming step of forming an outer portion of the tube forming portion except the head forming portion from the material by using a forming machine to reduce the outer diameter; A cutting step of dividing and forming a dividing groove in the axial direction in the unmolded head forming portion; A yoke forming step of forming a pair of yokes facing the head by pressing the cut head forming part; A pinhole forming step of forming a pinhole in the yoke; It is characterized in that it is produced by a spline boss molding step of forming a spline boss on the inner surface of the reduced hollow tube.

In manufacturing a universal joint consisting of a combination of the shaft joint and the pipe joint integrally formed with the fourth yoke; The pipe joint, a material preparation step of preparing a material by cutting the pipe to a predetermined length; A tube forming step of forming an outer portion of the tube forming portion except the head forming portion from the material by using a forming machine to reduce the outer diameter; A pre-yoke molding step of forming a pre-yoke through a pressing method (forging) in which a press-formed press is pressed into the head-forming part after inserting the unmolded head-forming part into a mold; A cutting step for forming a yoke for cutting the connected part except the yoke part in a rectangular cylindrical shape having an upper opening formed by the pre-yoke forming step; A pinhole forming step of forming a pinhole in the yoke; It is characterized in that it is produced by a spline boss molding step of forming a spline boss on the inner surface of the reduced hollow tube.

In the fifth material preparation step, the pipe is characterized by a seamless seamless pipe.

According to the universal joint manufacturing method using the pipe provided by the present invention, the cost reduction can be expected by manufacturing the shaft joint and the pipe joint integrally formed with the yoke using a seamless pipe.

In addition, productivity can be minimized by minimizing machining, and the interior can be provided in a hollow state, thereby reducing the weight of the finished universal joint, which can greatly contribute to the weight reduction of the automobile.

1 is a perspective view showing the appearance of the universal joint prepared and provided by the present invention

Figure 2 is a shaft joint manufacturing process diagram in the universal joint provided by the present invention

Figure 3 is a manufacturing process showing another example of the shaft joint in the universal joint provided by the present invention

Figure 4 is a pipe joint manufacturing process diagram in the universal joint provided by the present invention

Figure 5 is a manufacturing process showing another example of the pipe joint in the universal joint provided by the present invention

Hereinafter, a method of manufacturing a universal joint using a pipe provided by the present invention will be described with reference to the accompanying drawings.

1 is a perspective view showing the appearance of the universal joint prepared and provided by the present invention.

The automobile is applied to a steering device provided by the driver to arbitrarily change the direction of travel of the vehicle.

The steering device is installed in front of the driver's seat and the steering wheel for changing the driving direction of the vehicle by the driver's operation, the steering column is installed on the lower portion of the steering wheel, and converts the rotational movement of the steering wheel into a straight motion and At the same time it includes a steering gear box for changing the direction of the tire by increasing the steering force, and a universal joint (1) for transmitting the rotational force transmitted to the steering column to the steering gear box.

The universal joint 1 is composed of a shaft joint 2 and a pipe joint 3 for transmitting rotational force to the shaft joint 2 as shown in FIG. 1, and the outer surface of the shaft joint 2 is splined in an uneven form. A shaft 27 is formed, and a spline boss 37 is formed on the inner surface of the pipe A joint 3 so as to slide in the axial direction while the rotational force is transmitted while both members are fitted. At this time, the contact surface of the spline shaft 27 and the spline boss 37 is provided in a configuration via the bearing (4) to reduce the friction force.

The universal joint (1) using the pipe (A) provided by the present invention is different from the shaft joint (2) configured as described above and the pipe joint (3) by using a pipe (A), unlike the conventional round bar material By manufacturing, it is possible to meet the durability while providing the effect of manufacturing cost reduction, productivity improvement, weight reduction of the product.

Hereinafter, a method of manufacturing the shaft joint 2 and the pipe joint 3 using the pipe A will be described in detail.

-샤프트 조인트 제조-Shaft Joint Manufacturer

Figure 2 illustrates a shaft joint manufacturing process diagram in the universal joint provided by the present invention.

The manufacturing process of the shaft joint 2 in which the yoke 25 was integrally formed in the universal joint 1 using the pipe A of this invention; 1) Material preparation step (S11), 2) Shaft forming step (S12), 3) Cutting step (S13) and 4) Yoke forming step (S14), 5) Pin hole for forming the head which is part of the yoke 25 Forming step (S15), 6) is made by the sequence of the spline shaft forming step (S16), each of these steps will be described in detail below.

1) Material preparation stage (S11)

A pipe A having a predetermined diameter is cut into a predetermined length using a cutter to prepare a material B. At this time, the preferred diameter of the pipe (A) is to use a diameter corresponding to the head forming portion 21 to be described later. In addition, in the case of the pipe (A), it is preferable to use the seamless seamless pipe (A) in consideration of the phenomenon of the tread during the manufacturing process.

2) shaft forming step (S12)

As described above, the material B provided by cutting the pipe A to a predetermined length may be divided into the head forming part 21 and the shaft forming part 22, and the shaft 23 forming process may include the shaft forming part 22. ) Is a step of forming the shaft 23 by reducing the diameter of the.

Preferably, the shaft 23 is formed by reducing the outer diameter by inserting the shaft forming portion 22 except for the head forming portion 21 from the material B into a forming machine.

As described above, when forming the shaft 23 by using the forming machine, the outer diameter is reduced, and as the length is increased, the hollow shape is increased in thickness, thereby providing an effect of reducing weight while maintaining durability. .

In the forming process using the forming machine as described above, it is preferable to gradually reduce the diameter by repeating the process once or several times depending on the reduction degree of the outer diameter of the shaft 23.

3) cutting step (S13)

In the case of the head shaping portion 21, the dividing groove 24 is formed by cutting the head shaping portion 21, which has not been reduced in the preliminary process for forming the yoke 25, in the axial direction by using a cutter or a metal laser cutter. It is a process of forming and dividing.

4) Yoke molding step (S14)

The yoke forming step (S14) is a pressing method for pressing the press upper mold into the head forming part 21 after inserting the cut head forming part 21 into the mold in the process of forming a pair of facing yokes 25. Through forging, a pair of facing yokes is formed.

5) Pinhole forming step (S15)

In the case of the yoke 25 formed in the head forming portion 21, a pin hole 26 is required in which a neighboring side yoke 25 and a needle roller bearing coupled to the cross shaft are assembled. ), Pin holes 26 are formed.

The pin hole 26 is drilled in a state in which a sufficient thickness is provided by a drawing process using a press to be processed to a desired diameter so that the needle roller bearing can be stably assembled.

6) Spline Shaft Molding Step (S16)

As described above, the spline shaft 27 is formed on the outer surface of the hollow shaft 23 which is reduced by foaming.

3 is a manufacturing process diagram showing another example of the shaft joint in the universal joint provided by the present invention.

The manufacturing process of the shaft joint 2 in which the yoke 25 was integrally formed in the universal joint 1 using the pipe A of this invention; 1) Material preparation step (S111), 2) Shaft forming step (S112), 3) Preliminary yoke forming step (S113), 4) Cutting step for forming the yoke (S114) and 5) Pinhole forming step (S115), 6) the spline shaft forming step (S116) is made by the sequence, each of these steps will be described in detail below.

1) Material preparation stage (S111)

A pipe A having a predetermined diameter is cut into a predetermined length using a cutter to prepare a material B. At this time, the preferred diameter of the pipe (A) is to use a diameter and thickness that corresponds to the head forming portion 21 to be described later. In addition, in the case of the pipe (A), it is preferable to use the seamless seamless pipe (A) in consideration of the phenomenon of the tread during the manufacturing process.

2) shaft forming step (S112)

In the forming process using the forming machine as described above, it is preferable to repeatedly reduce the diameter by repeating the process several times according to the reduction degree of the outer diameter of the shaft 23.

3) pre-yoke molding step (S113)

In the case of the pipe (A) is made of a configuration having a diameter corresponding to the head forming portion, after the head forming portion is put into the mold, preliminary through a pressing method (forging) to press the press upper mold into the head forming portion 21 inside Mold the yoke.

At this time, a pair of opposing yokes are connected to each other, as if the upper portion is formed in a rectangular cylinder shape opening.

4) cutting step for yoke formation (S114)

The cutting step is to allow the yoke to be provided. The yoke formed by the preliminary yoke forming step has a structure connected to each other. In the cutting step, the cutting parts are cut except for the yoke part.

The cutting process may be performed in a machine tool such as milling or a metal laser cutting machine.

5) Pinhole forming step (S115)

6) Spline Shaft Forming Step (S116)

The spline shaft molding may be performed by any one of a press method, a molding using a forming machine, and a rolling method, and such a molding method may be applied to a commonly used method, and thus detailed description thereof will be omitted.

-파이프 조인트 제조-Pipe joint manufacturing

4 is a view illustrating a pipe joint manufacturing process in the universal joint provided in the present invention.

The manufacturing process of the pipe joint 3 in which the yoke 35 was integrally formed in the universal joint 1 using the pipe A of this invention; 1) Material preparation step (S21), 2) Tube forming step (S22), 3) Cutting step (S23) and 4) Yoke forming step (S24), 5) Pin hole for forming the head which is a part of the yoke 35 Forming step (S25), it is characterized in that 6 is produced by the spline boss forming step (S26).

1) Material preparation stage (S11)

A pipe A having a predetermined diameter is cut into a predetermined length using a cutter to prepare a material B. At this time, the preferred diameter of the pipe (A) is to use a diameter corresponding to the head forming portion 31 to be described later. In addition, in the case of the pipe (A), it is preferable to use a seamless seamless pipe in consideration of the phenomenon of tread in the manufacturing process.

2) tube forming step (S22)

The material (B) provided by cutting the pipe (A) to a predetermined length as described above may be divided into the head forming portion 31 and the tube forming portion 32, the tube forming process is the tube 33 forming portion 32 ) Is a step of molding the tube 33 by reducing the diameter.

Preferably, in the shaft joint 2, the tube 33 is formed by reducing the outer diameter by inserting the tube forming portion 32 except for the head forming portion 31 from the material B into a forming machine. To allow the spline shaft 27 portion to be embedded.

As described above, when forming the tube 33 by using the forming machine, the outer diameter is reduced, and as the length is increased, the hollow shape is increased in thickness, thereby providing an effect of reducing weight while maintaining durability. .

In the forming process using the forming machine as described above, it is preferable to gradually reduce the diameter by repeating one or several times according to the reduction degree of the outer diameter of the tube 33.

3) cutting step (S13)

In the case of the head shaping portion 31, the dividing groove 34 is formed by cutting the head shaping portion 31, which is not reduced in the preliminary process for forming the yoke 35, using a cutter or a metal laser cutter in the axial direction. It is a process of forming and dividing.

4) Yoke molding step (S14)

The yoke forming step (S14) is a pressing method for pressing the press upper mold into the head forming part 31 after inserting the cut head forming part 31 into the mold in the process of forming a pair of facing yokes 35. Through forging, a pair of facing yokes is formed.

5) Pinhole forming step (S15)

In the case of the yoke 35 formed in the head forming portion 31, a pin hole 36 is required in which the neighboring side yoke 35 and the needle roller bearings coupled to the cross shaft are assembled. Pin hole 36 is formed.

The pin hole 36 is drilled in a state in which a sufficient thickness is provided by a drawing process using a press to be processed to a desired diameter so that the needle roller bearing can be stably assembled.

6) spline boss molding step (S16)

As described above, the spline boss 37 is formed on the inner surface of the reduced hollow tube 33 by forming a pipe (A) forming machine.

5 is a manufacturing process diagram showing another example of the pipe joint in the universal joint provided by the present invention.

The manufacturing process of the pipe joint 3 in which the yoke 35 was integrally formed in the universal joint 1 using the pipe A of this invention; 1) material preparation step (S211), 2) tube forming step (S212), 3) pre-yoke molding step (S213), 4) cutting step for yoke molding (S214) and 5) pinhole molding step (S215), 6) it is characterized in that it is manufactured by the spline boss forming step (S216).

1) Material preparation stage (S111)

A pipe A having a predetermined diameter is cut into a predetermined length using a cutter to prepare a material B. At this time, the preferred diameter of the pipe (A) is to use a diameter and thickness that corresponds to the head forming portion 31 to be described later. In addition, in the case of the pipe (A), it is preferable to use a seamless seamless pipe in consideration of the phenomenon of tread in the manufacturing process.

2) tube forming step (S212)

3) pre-yoke molding step (S213)

In the case of the pipe A, the pre-yoke is formed through a pressing method (forging) in which the press forming die is pressed into the head forming part after the head forming part is put into the mold. do.

4) cutting step for yoke formation (S214)

5) Pinhole forming step (S215)

6) spline boss molding step (S216)

The spline boss 37 may be formed by any one of a press method, a molding using a forming machine, and a rolling method. Such a molding method may be applied to a method commonly used, and thus detailed description thereof will be omitted.

Although not mentioned in the present invention, the spline shaft 27, the spline boss 37, and the

yoke

25 and 35 formed in the shaft joint 2 and the pipe joint 3 are for the purpose of improving wear resistance. It is natural to add further heat treatment process.

As described above, when the shaft joint 2 and the pipe joint 3 are manufactured by the method of manufacturing the universal joint 1 using the pipe A, the cost of the material B can be drastically reduced compared to forging a conventional round bar. In particular, the shaft joint (2) can be provided in a hollow form that can significantly reduce the weight of the product, will also contribute to efforts to reduce the weight of the parts in order to improve fuel efficiency in the automotive industry.

In the detailed description of the present invention, specific embodiments have been described, but various modifications may be made without departing from the scope of the present invention. Therefore, the protection scope of the present invention should not be limited to the described embodiments, but should be defined by equivalents as well as the following claims.

Claims

In the manufacture of a universal joint (1) consisting of a combination of a shaft joint (2) and a pipe joint (3) in which yokes (25) (35) are integrally formed;

The shaft joint 2, the material preparation step (S11) for preparing a material (B) by cutting the pipe (A) to a predetermined length;

Shaft forming step (S12) of forming a shaft 23 by reducing the outer diameter by forming the outside of the shaft shaping portion 22, except for the head shaping portion 21 in the material (B) with a forming machine;

A cutting step (S13) of dividing and forming a dividing groove 24 in the axial direction in the unmolded head forming portion 21;

A yoke forming step (S14) of pressing the cut head forming part 21 to form a pair of yokes 25 facing the head;

A pinhole forming step S15 of forming a pinhole 26 in the yoke 25;

The method of manufacturing a universal joint using a pipe, characterized in that the spline shaft forming step (S16) to form a spline shaft 27 on the outer surface of the reduced hollow shaft (23).
In the manufacture of a universal joint (1) consisting of a combination of a shaft joint (2) and a pipe joint (3) in which yokes (25) (35) are integrally formed;

The shaft joint 2, the material preparation step (S111) for preparing a material (B) by cutting the pipe (A) to a predetermined length;

Shaft forming step (S112) of forming the shaft 23 by reducing the outer diameter by forming the outside of the shaft shaping portion 22, except for the head shaping portion 21 in the material (B) with a forming machine;

A pre-yoke molding step of molding the pre-yoke through a pressing method (forging) in which the press-form is pressed into the head-forming part 21 after the non-shrinked head-forming part 21 is put into the mold; (S113)

A cutting step for forming the yoke for cutting the connected portion except the yoke portion in the shape of the rectangular cylinder having an upper opening formed by the pre-yoke forming step; (S114)

A pinhole forming step (S115) of forming a pinhole 26 in the yoke 25;

Universal joint manufacturing method using a pipe, characterized in that produced by the spline shaft forming step (S116) to form a spline shaft 27 on the outer surface of the reduced hollow shaft (23).
In manufacturing a universal joint 1 consisting of a combination of a shaft joint 2 and a pipe joint 3 in which the yoke 25 is integrally formed;

The pipe joint 3, the material preparation step (S21) for preparing the material (B) by cutting the pipe (A) to a predetermined length;

Tube forming step (S22) of forming the outside of the tube forming portion 32, except for the head forming portion 31 in the material (B) with a pipe (A) forming machine to reduce the outer diameter;

A cutting step (S23) of dividing and forming a dividing groove 34 in the axial direction in the unmolded head forming portion 31;

A yoke forming step (S24) of pressing the cut head forming part 31 to form a pair of yokes 35 facing the head;

A pinhole forming step (S26) for forming the pinhole 36 in the yoke 35;

Universal joint manufacturing method using a pipe, characterized in that produced by the spline boss forming step (S27) to form a spline boss 37 on the inner surface of the reduced hollow tube (33).
In manufacturing a universal joint 1 consisting of a combination of a shaft joint 2 and a pipe joint 3 in which the yoke 25 is integrally formed;

The pipe joint 3, the material preparation step (S211) for preparing the material (B) by cutting the pipe (A) to a predetermined length;

Tube forming step (S212) for reducing the outer diameter by forming the outside of the tube forming portion 32, except for the head forming portion 31 in the material (B) with a pipe (A) forming machine;

A pre-yoke molding step (S213) of molding the pre-yoke through a pressing method (forging) in which the press-shaped upper mold is pressed into the head forming portion 21 after the non-shrinked head forming portion 31 is put into the mold;

A cutting step (S214) for forming a yoke for cutting the connected portion except for the yoke portion in a rectangular cylindrical shape having an upper portion formed by the pre-yoke forming step;

A pinhole forming step (S215) for forming a pinhole 36 in the yoke 35;

Universal joint manufacturing method using a pipe, characterized in that produced by the spline boss forming step (S216) to form a spline boss 37 on the inner surface of the reduced hollow tube (33).
The method according to any one of claims 1 to 4;

Pipe (A) in the material preparation step (S11) (S111) (S21) (S211) is a universal joint manufacturing method using a pipe, characterized in that the seamless seamless pipe.