JPH11320274A - Structure and method for connecting metal pipes to each other or connecting metal pipe to metal bar - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve the coaxial accuracy by leading a metal pipe or a metal bar into other metal pipe with a space between an outer peripheral part of a tip of the former metal pipe or metal bar and an inner peripheral part of the later metal pipe, and connecting them at a rear part as an interface with the plastic deforming pressure of the inner peripheral member of the first metal pipe. SOLUTION: A first metal pipe 1 is provided with a lead-in hole 11 at a central part of the inner periphery thereof, and provided with an interface part 12 continuously to a rear part of the lead-in hole 11. On the other hand, an outer peripheral part of a tip of a second metal pipe 2 is pressed into or smoothly fitted in the lead-in hole 11 of the first metal member 1 so as to maintain the coaxial accuracy. A rear pipe 22 continued to the peripheral part 21 of the tip is fitted in the interface part 12 in the matching condition, and the inner peripheral member of a rear end 13 of the first metal pipe 1 is connected to a previously formed connection groove 23 at a part or over the whole area or intermittently by the plastic deforming pressure of the plastic deformation by the cold forging.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a connection structure between metal tubes or a connection between a metal tube and a metal rod and a method of connecting the metal tubes, and is particularly suitable for a hollow shaft or the like that requires coaxial accuracy.

[0002]

2. Description of the Related Art Generally, metal pipes or metal pipes and metal rods are arbitrarily selected according to the intended use, such as a welded article, a press-fitted article, or a coupling using a coupling. In recent years, a technique of joining by utilizing plastic deformation of a metal pipe has been widely adopted. The representative one is
As disclosed in JP-A-58-125322, a large-diameter stepped tube portion is provided at one end of one metal tube by flaring to provide a large-diameter stepped tube portion.
After providing a small-diameter stepped pipe part having an outer diameter corresponding to the inner diameter of the large-diameter stepped pipe part at one end of the other metal pipe by flare processing, after loosely inserting the large-diameter stepped pipe part into the small-diameter stepped pipe part, A method is known in which pressure is applied to the inclined surface of the large-diameter stepped pipe portion to crush it, and a narrow flange is formed so as to tightly close a part of the large-diameter stepped portion to the small-diameter stepped pipe portion. ing.

[0003]

In the above-mentioned prior art, a small-diameter stepped pipe portion and a large-diameter step portion are provided by flaring, and the two are loosely inserted and positioned. In addition, in order to increase the coaxial accuracy, it is necessary to rely on a coupling jig as much as possible, and it is difficult to increase the productivity and obtain a product with high coaxial accuracy.

An object of the present invention is to provide a connecting structure of metal pipes or a metal pipe and a metal rod having high coaxial accuracy and high productivity, and a connecting method thereof.

[0005]

SUMMARY OF THE INVENTION The present invention is directed to a first metal pipe and a second metal pipe or metal rod inserted into the inner diameter of the metal pipe and joined by plastic deformation of the first metal pipe. In the metal tube or metal tube and metal rod joining structure, the outer periphery of the tip of the second metal tube or the metal bar is introduced into the inner periphery of the first metal tube with a certain width, This is achieved by a metal tube-to-metal tube or metal tube-to-metal bar connection structure, characterized in that the joined rear portions are joined by plastic deformation pressure of the inner peripheral member of the first metal tube.

Preferably, in the present invention, the first metal tube and the second metal tube are connected to each other.
The metal tube or the metal rod is made of a dissimilar metal and one of them is of high quality.

[0007] Preferably, the present invention is attained by a structure in which the second metal tubes or the metal bars are provided with a connecting groove in an outer peripheral portion where the second metal tubes or the metal bars are joined to each other, or a connecting structure of the metal tubes and the metal bars. You.

Preferably, in the present invention, the first metal tube is made of stainless steel, and the second metal tube or the metal bar is made of iron. Achieved.

According to the present invention, the tip of a second metal tube or a metal rod is press-fitted into an inner peripheral introduction hole of a first metal tube to secure coaxial accuracy, and thereafter, the rear portion of the first metal which is statically fitted. This is achieved by a method of joining metal tubes or a combination of metal tubes and metal rods, characterized in that the inner peripheral edge portion is locally pressed in the axial direction to be plastically deformed and the two are joined.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to FIGS. FIG. 1 is a view showing a state in which metal tubes are connected to each other. Specifically, the first metal tube 1 is made of stainless steel, and has an introduction hole 11 at the center of the inner periphery. Thus, a so-called static mating portion 12 is provided. On the other hand, the second metal pipe 2 is made of a structural carbon steel material (S35C).
The outer peripheral portion 21 is press-fitted or slid into the introduction hole 11 of the first metal member 1 to maintain coaxial accuracy. The width of the introduction hole 11 is arbitrarily determined in consideration of the length or thickness of the members to be connected.

A rear tube 22 following the distal end outer peripheral portion 21 is fitted in the static fitting portion 12 in a so-called static state.
The inner peripheral member of the rear end portion 13 of the first metal tube 1 is plastically deformed by cold forging locally or intermittently in the connecting groove 23 in which a preformed groove 23 is formed. Are mechanically coupled and maintained. In the members connected in this manner, the coaxial accuracy between the two members is secured by the introduction hole 11, and the plastic deformation pressure applied to the connection groove 23 works effectively against the rotational torque, and the coaxial accuracy is high and the coupling force is high. A tall metal tube-to-metal tube or metal tube-to-metal bar connection structure is provided simply and easily. The metal tube joined by such a structure is suitable for a rotating shaft of an electric motor or the like because of high coaxial accuracy and high mechanical joining force as described above. Is particularly effective for a rotating shaft of a washing machine or the like located on a motor shaft and the other is located in a water tub, so that a lightweight and highly environmentally friendly structure can be provided.

The combination of the metal tubes to be connected is the first
The material of the metal tube is not limited as long as it can be plastically deformed by cold. Further, although the shape of the coupling groove 23 is various, it is not necessary to provide the coupling groove 23 if necessary, and a rough surface may be sufficient.

Next, a method of connecting the above structures will be described with reference to FIGS.
This will be described with reference to FIG. Introducing hole 11 and static mating part 12 in advance
The first metal tube 1 formed with the first metal tube 2 is disposed on jigs 3 and 4 to restrain the periphery thereof, and the second metal tube 2 to be joined from above is connected.
Is lowered by a press machine. The second metal pipe 2 that has moved smoothly in the area of the static fitting portion 12 is concentrically positioned in the area of the introduction hole 11 and descends to the position in FIG. 3 to form a temporary connection. Both members provisionally determined in this way are:
In the next step, when the rear inner peripheral edge of the first metal tube 1 is locally pressed in the axial direction by the teeth of the punch 5 descending with the second metal tube 2 as a guide shaft, the pressed member is Since the periphery is restricted, the plastic flows in the direction of the coupling groove 23, and the two members are mechanically plastically coupled to each other. Since such a connection does not apply any external force to the introduction hole, the coaxial accuracy by the initial press-fitting is maintained, and as a result, a connection structure of a metal tube with high coaxial accuracy can be easily and reliably provided.

Although the first embodiment has described the connection structure between metal tubes and the method therefor, the connection between the metal tube and the metal rod is essentially the same, so a detailed description is omitted.

[0015]

The outer peripheral portion of the tip of the second metal tube or the metal rod is introduced with a certain width into the inner peripheral portion of the first metal tube, and the rear portion of the second metal tube or the metal rod is joined to the inside of the first metal tube. Since the connection is performed by the plastic deformation pressure of the peripheral members, it is possible to provide a connection structure between metal tubes with high coaxial accuracy or a connection structure between a metal tube and a metal rod.

The tip of the second metal tube or the metal rod is press-fitted into the inner circumference introduction hole of the first metal tube to ensure coaxial accuracy,
Thereafter, the rear inner peripheral edge of the first metal, which is statically joined, is locally pressed from the axial direction to be plastically deformed, and the two are connected to each other. A coupling structure can be easily and reliably provided.

[Brief description of the drawings]

FIG. 1 is a partial sectional view showing a connection between metal tubes in an embodiment of the present invention.

FIG. 2 is a first stroke diagram of a coupling stroke in the embodiment.

FIG. 3 is a second stroke diagram of the coupling stroke;

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... 1st metal pipe, 2 ... 2nd metal pipe, 11 ... introduction hole,
12 ... static fitting part, 21 ... tip outer peripheral part, 22 ... rear pipe, 23
... the coupling groove.

Claims (5)

[Claims] 1. A metal pipe or a metal pipe comprising a first metal pipe and a second metal pipe or a metal rod inserted into an inner diameter portion of the metal pipe and joined by plastic deformation of the first metal pipe. In the connecting structure of the tube and the metal rod, the outer peripheral portion of the distal end of the second metal tube or the metal rod is introduced with a certain width into the inner peripheral portion of the first metal tube, and the rear portion of the second metal tube or the metal rod is joined to the first metal tube. A metal tube or a metal tube and a metal rod are connected to each other by a plastic deformation pressure of an inner peripheral member of the metal tube. 2. The metal pipes according to claim 1, wherein the first metal pipe and the second metal pipe or the metal rod are dissimilar metals and one of them is of high quality. Stick connection structure. 3. A metal pipe or a metal rod according to claim 1, wherein said second metal pipe or said metal rod is provided with a coupling groove in an outer peripheral portion where said second metal pipe or said metal rod is fitted. Construction. 4. The metal pipes according to claim 2, wherein the first metal pipe is made of stainless steel, and the second metal pipe or the metal rod is made of iron. Construction. 5. A coaxial precision is ensured by introducing a tip of a second metal tube or a metal rod into an inner circumference introduction hole of the first metal tube,
A method of joining metal pipes or metal pipes and metal rods, characterized in that the rear inner peripheral edge of the first metal to be joined is plastically deformed by locally pressing it from the axial direction, and the two are joined together. .