JP2010158712A - Method for joining pipe - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for joining a pipe which achieves a high reliability of durability at the junction area. <P>SOLUTION: The method of joining pipes includes a step of preparing a thin-wall pipe 31 having a relatively small wall thickness T<SB>B</SB>and a thick-wall pipe 21 having a relatively large wall thickness T<SB>A</SB>and also having a joint surface 21a, which has a smaller wall thickness T<SB>C</SB>than the thickness T<SB>A</SB>of the thin-wall pipe 31 and is joined to the thin-wall pipe 31, and a step of joining the thin-wall pipe 31 to the thick-wall pipe 21 by friction pressure welding. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention generally relates to a pipe joining method, and more particularly to a pipe joining method using a friction welding method.

  Regarding a conventional pipe joining method, for example, Japanese Patent Application Laid-Open No. 2004-141933 avoids the occurrence of a sharp edge, which is a starting point of fatigue fracture of a burr corner portion generated in a press-contact portion between a thin pipe and a thick pipe. A method of friction welding of a propeller shaft for the purpose of improving the durability reliability of the part is disclosed (Patent Document 1). In the propeller shaft friction welding method disclosed in Patent Document 1, the inner diameter of the thin pipe is set smaller than the inner diameter of the thick pipe.

  Japanese Patent Application Laid-Open No. 2005-271016 discloses a friction welding method between a steel pipe and an aluminum alloy hollow member for the purpose of suppressing deformation of the aluminum alloy pipe at the time of joining while obtaining high joint strength. (Patent Document 2). Japanese Patent Application Laid-Open No. 2002-224857 discloses a bonding structure between different metal hollow members for the purpose of obtaining good bonding strength while hardly leaving an intermetallic compound, oxide or the like at the bonding interface, and its bonding. A method is disclosed (Patent Document 3).

JP 2004-141933 A JP 2005-271016 A JP 2002-224857 A

  As disclosed in the above-mentioned Patent Document 1, a friction welding method is used as a means for joining pipes in a manufacturing process of a propeller shaft. In the friction welding method, frictional heat is generated by relatively rotating both pipes in a state where the end faces of the pipes are in contact with each other, and the pipes are joined by this frictional heat. At this time, the end face of the pipe is deformed to generate a curled burr. However, if the burr is formed in a sharp edge shape that rises rapidly from the peripheral surface of the pipe, the durability reliability of the pipe joint portion may be impaired.

  Accordingly, an object of the present invention is to solve the above-mentioned problems and to provide a pipe joining method that can obtain excellent durability and reliability at the joint portion.

  A method for joining pipes according to one aspect of the present invention includes a step of preparing a first pipe formed with a relatively small thickness and a second pipe formed with a relatively large thickness; Joining the first pipe and the second pipe by a friction welding method. The second pipe has a joint surface with respect to the first pipe formed to a thickness smaller than the thickness of the first pipe.

  According to the pipe joining method configured in this way, the second pipe has a joining surface formed with a thickness smaller than the thickness of the first pipe, so that burrs generated in the joining process are generated from the second pipe side. The force received can be kept small. Thereby, it can suppress that the burr | flash of the sharp edge shape which goes to the thin 1st pipe side is formed. As a result, excellent durability reliability can be obtained at the joint between the first pipe and the second pipe.

  According to another aspect of the present invention, there is provided a pipe joining method comprising: preparing a first pipe having a relatively small strength and a second pipe having a relatively large strength; and a first pipe and a second pipe. Joining the pipe by a friction welding method. The second pipe has a joint surface with respect to the first pipe formed to a thickness smaller than the thickness of the first pipe.

  According to the pipe joining method configured in this way, the second pipe has a joining surface formed with a thickness smaller than the thickness of the first pipe, so that burrs generated in the joining process are generated from the second pipe side. The force received can be kept small. Thereby, it can suppress that the burr | flash of the sharp edge shape which goes to the low intensity | strength 1st pipe side is formed. As a result, excellent durability reliability can be obtained at the joint between the first pipe and the second pipe.

  Preferably, the step of joining the first pipe and the second pipe is performed so that the joint surface of the second pipe is included in the joint surface of the first pipe in the radial direction of the first pipe and the second pipe. A step of matching the first pipe and the second pipe.

  According to the pipe joining method configured as described above, it is possible to suppress the formation of a burr having a sharp edge shape toward the thin or low-strength first pipe.

  As described above, according to the present invention, it is possible to provide a pipe joining method capable of obtaining excellent durability reliability at a joint portion.

It is sectional drawing which shows a part of propeller shaft. It is sectional drawing which shows the manufacturing process of the propeller shaft in FIG. It is sectional drawing which shows the process of the joining method of the pipe in Embodiment 2 of this invention.

  Embodiments of the present invention will be described with reference to the drawings. In the drawings referred to below, the same or corresponding members are denoted by the same reference numerals.

(Embodiment 1)
FIG. 1 is a cross-sectional view showing a part of a propeller shaft. Referring to FIG. 1, propeller shaft 10 is mounted on a vehicle and typically serves to transmit power from a transmission to a drive-side axle. The propeller shaft 10 is manufactured by using the pipe joining method in the present embodiment described below.

  The propeller shaft 10 is formed by joining a thick pipe 21 and a thin pipe 31. In the present embodiment, the thick pipe 21 is composed of a long cylindrical member constituting the tube of the propeller shaft 10. The thin pipe 31 constitutes a joint yoke that functions as a connecting portion, and is composed of a short cylindrical member as compared with the thick pipe 21. The thick pipe 21 and the thin pipe 31 are arranged coaxially.

  The thick pipe 21 and the thin pipe 31 are made of metal. The thick pipe 21 and the thin pipe 31 may be formed from the same metal or may be formed from different metals.

  FIG. 2 is a cross-sectional view showing a manufacturing process of the propeller shaft in FIG. In the drawing, a portion corresponding to the range surrounded by the two-dot chain line II in FIG. 1 is shown enlarged.

Referring to FIG. 2, first, to describe the basic steps of the method for joining the pipe of the present embodiment, the joining method of the pipe in this embodiment, formed in a relatively small thickness T _{B A} step of preparing a thin pipe 31 as a first pipe and a thick pipe 21 as a second pipe formed to a relatively large thickness TA, and friction welding the thin pipe 31 and the thick pipe 21 Joining by a method. Thick pipe 21 has a bonding surface 21a with respect to the thin pipe 31 formed to a small thickness T _C than the thickness T _A thin pipe 31.

Next, the steps of the pipe joining method in the present embodiment will be described in detail.
With reference to FIG. 2A, first, a thin pipe 31 and a thick pipe 21 are prepared. Thin pipe 31 has a thickness _{T B,} thickness pipe 21 has a larger wall thickness _{T A} than the thickness _{T B.} The thick pipe 21 and the thin pipe 31 have a joint surface 21a and a joint surface 31a, respectively. The joining surface 21a and the joining surface 31a are formed at the tips of the thin pipe 31 and the thick pipe 21 extending in a cylindrical shape, respectively.

The thick pipe 21 has a tapered portion 25. The tapered portion 25 is formed in a tapered shape so that the diameter of the thick pipe 21 decreases as the outer peripheral surface approaches the joint surface 21a, and the diameter increases as the inner peripheral surface of the thick pipe 21 approaches the joint surface 21a. Has been. Thin pipe 31 is formed to have a constant thickness T _B toward the bonding surface 31a. Thick pipe 21, in a joint surface 21a, has a smaller wall thickness _{T C} than the thickness _{T B.}

  The thin pipe 31 and the thick pipe 21 are coaxially positioned so that the joint surface 31a and the joint surface 21a face each other.

  Next, referring to FIG. 2B, the thin pipe 31 and the thick pipe 21 are joined by a friction welding method.

  More specifically, the thin pipe 31 and the thick pipe 21 are relatively rotated in a state where the joint surface 31a of the thin pipe 31 and the joint surface 21a of the thick pipe 21 are in contact with each other. At this time, in the radial direction of the thin pipe 31 and the thick pipe 21, the thin pipe 31 and the thick pipe 21 are pushed so that the joint surface 21a of the thick pipe 21 is included in the joint surface 31a of the thin pipe 31. Hit it. In other words, in the axial direction of the thin pipe 31 and the thick pipe 21, when the joint surface 21a is projected onto the joint surface 31a, the entire projected joint surface 21a is included in the joint surface 31a.

  Referring to FIG. 2C, frictional heat is generated between the joining surface 31a and the joining surface 21a, and the thin pipe 31 and the thick pipe 21 are joined using this frictional heat.

  In the joining step of the thin pipe 31 and the thick pipe 21 by the friction welding method described above, the press-contact curl 47 and the press-contact curl 42 are generated on the inner peripheral side of the thin pipe 31 and the thick pipe 21, respectively. A pressure contact curl 46 and a pressure contact curl 41 are generated on the outer peripheral sides of the pipe 31 and the thick pipe 21, respectively.

In this embodiment, the thickness of the pipe 21, the configuration of the tapered portion 25 having a smaller wall thickness T _C than the thickness T _B of the thin pipe 31 is formed, pressed curl 47 and pressure generated from the thin pipe 31 The curl 46 is not subjected to the pushing-up force from the thick pipe 21 and the pressure contact curls 42 and 41. Thereby, it is possible to prevent the base of the pressure-curled curl from being rounded and forming a sharp edge that serves as a starting point for fatigue recovery.

  Furthermore, in the present embodiment, the margin for the thin pipe 31 and the thick pipe 21 at the time of friction welding is set to be equal to or longer than the total length L of the tapered portion 25. Thereby, the joining area of the thin pipe 31 and the thick pipe 21 after completion of joining can be sufficiently secured.

  According to the pipe joining method according to the first embodiment of the present invention configured as described above, it is possible to suppress the formation of a sharp edge at the joining portion of the thin pipe 31 and the thick pipe 21, and the propeller shaft 10. Durability reliability can be improved.

  In the present embodiment, the case where the thick pipe 21 is disposed on the tube side of the propeller shaft 10 and the thin pipe 31 is disposed on the joint yoke side has been described. The structure by which the thick pipe 21 is arrange | positioned reversely may be sufficient.

(Embodiment 2)
FIG. 3 is a cross-sectional view showing steps of a pipe joining method according to Embodiment 2 of the present invention. The pipe joining method according to the present embodiment basically includes the same steps as the pipe joining method according to the first embodiment. Hereinafter, the description of the overlapping steps will not be repeated.

With reference to FIG. 3, first, a basic process of the pipe joining method in the present embodiment will be described. The pipe joining method in the present embodiment is low as a first pipe having a relatively small strength. A step of preparing a strength pipe 131 and a high strength pipe 121 as a second pipe having a relatively large strength, and a step of joining the low strength pipe 131 and the high strength pipe 121 by a friction welding method. High strength pipe 121 has a bonding surface 121a for low strength pipe 131 formed in a small thickness _{T E} than the thickness _{T D} of the low-intensity pipe 131.

Next, the steps of the pipe joining method in the present embodiment will be described in detail.
Referring to FIG. 3A, first, a low-strength pipe 131 and a high-strength pipe 121 are prepared. In this embodiment, the low-strength pipe 131 and high-strength pipe 121 has a thickness _{T D.} The low-strength pipe 131 and the high-strength pipe 121 have a joint surface 131a and a joint surface 121a, respectively. The joining surface 131a and the joining surface 121a are formed at the tips of a low-strength pipe 131 and a high-strength pipe 121 that extend in a cylindrical shape, respectively.

The high strength pipe 121 has a tapered portion 125. The tapered portion 125 is formed in the same form as the tapered portion 25 in FIG. Low intensity pipe 131 is formed to have a constant thickness T _D toward the bonding surface 131a. High strength pipe 121, the bonding surface 121a, having a smaller wall thickness _{T E} than the thickness _{T D.}

  In the present embodiment, the case where the low-strength pipe 131 and the high-strength pipe 121 have the same thickness will be described, but the relationship between the thicknesses of both is not particularly limited.

  The material strength of the high-strength pipe 121 is higher than the material strength of the low-strength pipe 131. In the present embodiment, the high-strength pipe 121 has a higher strength than the low-strength pipe 131.

  Next, referring to FIGS. 3B and 3C, the joining surface 131a of the low-strength pipe 131 and the joining surface 121a of the high-strength pipe 121 are joined by a friction welding method. A pressure contact curl 147 and a pressure contact curl 142 are generated on the inner peripheral side of the low strength pipe 131 and the high strength pipe 121, respectively, and a pressure contact curl 146 and a pressure contact curl 141 are generated on the outer peripheral side of the low strength pipe 131 and the high strength pipe 121, respectively. To do.

In this embodiment, the high-strength pipe 121, with the configuration tapered portion 125 having a smaller wall thickness T _E than the thickness T _D of low intensity pipe 131 is formed, pressed curl 147 generated from low intensity pipes 131 In addition, the pressure contact curl 146 does not receive the force of pushing up from the high-strength pipe 121 and the pressure contact curls 142, 141. Thereby, it is possible to prevent the base of the pressure-curled curl from being rounded and forming a sharp edge that serves as a starting point for fatigue recovery.

  According to the pipe joining method in the second embodiment of the present invention configured as described above, the effects described in the first embodiment can be obtained in the same manner.

  The embodiment disclosed this time should be considered as illustrative in all points and not restrictive. The scope of the present invention is defined by the terms of the claims, rather than the description above, and is intended to include any modifications within the scope and meaning equivalent to the terms of the claims.

  The present invention is mainly used in a manufacturing process of a propeller shaft mounted on a vehicle.

  10 Propeller shaft, 21 Thick pipe, 21a, 31a, 121a, 131a Joint surface, 25, 125 Tapered part, 31 Thin pipe, 121 High strength pipe, 131 Low strength pipe.

Claims (3)

A first pipe formed with a relatively small thickness, and a joining surface for the first pipe formed with a relatively large thickness and smaller than the thickness of the first pipe. Preparing a second pipe;
A method for joining pipes, comprising: joining the first pipe and the second pipe by a friction welding method. A first pipe having a relatively small strength, and a second pipe having a relatively large strength and a joint surface with respect to the first pipe formed to a thickness smaller than the thickness of the first pipe; The process of preparing
A method for joining pipes, comprising: joining the first pipe and the second pipe by a friction welding method.   The step of joining the first pipe and the second pipe is performed so that the joint surface of the second pipe is included in the joint surface of the first pipe in the radial direction of the first pipe and the second pipe. The method for joining pipes according to claim 1, further comprising a step of abutting the first pipe and the second pipe.

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