JPH0899138A - Method for connecting pipe and structure for connecting part of pipe - Google Patents

Abstract

PURPOSE: To secure a firm and sure connection by deform-bulging the inner surface side at the pressurizing part of a copper pipe to the linear state and press-sticking one round of the circular surface of a flange of an aluminum pipe to the linear state. CONSTITUTION: The annular flange 5 bulge-expanding the diameter near the inserted end part of the aluminum pipe 3 is integrally formed so that this flange 5 have a specific thickness and rigidity. In the copper pipe 4, a large diameter part 8 and a part having larger diameter than the flange part 5 expanding the diameter to a connecting end part through the stepping parts 6, 7 step by step. The aluminum pipe 3 is inserted into the large diameter part of the copper pipe 4 to form a staking 10. In this condition, the pressure is applied so as to make one round as the linear state in the circular direction from the outer peripheral surface of the copper pipe 4 overlapping the circular surface of the flange 5 of the aluminum pipe 3 with the copper pipe 4, and the inner surface side at the pressurizing part of the copper pipe 4 is deform-bulged as the linear state and press-stuck as the linear state making one round of the circular surface of the flange 5. By this method, the air-tightness at the connecting part is secured and the working is facilitated.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of connecting pipes in a copper pipe and an aluminum pipe and a structure of a connecting portion of the pipes.

[0002]

2. Description of the Related Art Conventionally, a refrigerator provided in a domestic air conditioner, a vending machine, a refrigerator, etc., converts a low pressure gas evaporated by an evaporator into a high pressure gas by a compressor and sends it to a condenser, and a liquid by a condenser. It is well known that this liquid is a device that cools the surroundings by the endothermic action of the evaporator by the refrigeration cycle in which the liquid is reduced in pressure through the expansion valve and is reduced to the evaporator.

By the way, since aluminum is excellent in heat conduction and can be easily processed, an evaporator provided with an aluminum fin and an aluminum pipe is provided. The compressor is provided with a copper pipe, and the aluminum pipe of the evaporator and the copper pipe of the compressor are hermetically connected by a connecting means such as a union joint.

[0004]

[Problems to be Solved by the Invention] Although the aluminum pipe of the evaporator and the copper pipe of the compressor must be hermetically connected to each other, brazing is difficult because aluminum is weak against heat when connecting aluminum to copper. It is impossible, and on the other hand, aluminum and copper are the most suitable general connection means by pressure welding,
Even if the ends of two pipes are butted and connected, there is a problem that they are easily pulled apart because they are weak against pulling force.In addition, for example, the ends of another pipe are inserted into one pipe and the overlapping parts are pressed together. Even if an attempt is made, pressure cannot be applied from the inner side of the pipe because it is impossible to insert the pressure member inside the pipe, and therefore, both sides of the pipe, that is, the outer peripheral surface of the pipe, It is impossible to apply pressure from both sides to the inner peripheral surface, and for this reason, connecting means such as a union joint is used to connect the aluminum pipe of the evaporator and the copper pipe of the compressor. We have no choice but to employ it. However, such a connecting means has a problem that the manufacturing cost of the union joint is expensive and uneconomical.

The present invention has been made in view of the above points, and an object of the present invention is to form an annular flange-like flange that expands and expands near the insertion end of an aluminum pipe, and the flange is With rigidity, insert this flange into the large diameter part provided at the end of the copper pipe, apply mechanical pressure from the surface of the copper pipe at the overlapping part of this flange and the large diameter part, pressurize Pipe connection method and pipe connection structure in which a circumferential ridge that deforms and bulges toward the inner surface side of a copper pipe by plastically deforming and pressing it into the peripheral surface of the flange of an aluminum pipe Is provided.

[0006]

In order to achieve the above object, in the pipe connecting method according to the present invention, an aluminum pipe is integrally formed with a bulging and expanding annular flange-shaped flange near the insertion end. Then, a two-step large-diameter portion is formed at the connecting end of the copper pipe, which gradually expands in diameter from the rear end toward the opening side, and the tip of the aluminum pipe is inserted into the large-diameter portion at the rear end of the copper pipe. The flange is inserted into the large diameter part on the opening side of the copper pipe, and the opening of the copper pipe is crimped to connect the aluminum pipe to the copper pipe.In this state, the circumferential surface of the flange of the aluminum pipe and the body pipe overlap. A pressure is applied from the outer peripheral surface of the copper pipe in a circumferential direction in a circumferential direction, and the inner surface side of the pressurizing portion of the copper pipe is deformed and bulged in a streak shape to form the circumferential surface of the flange of the aluminum pipe. Go around It is intended to crimp to Jo.

Further, in the pipe connecting structure of the present invention, the aluminum pipe has a flange-like flange which is expanded and enlarged near the insertion end, and the copper pipe is stepped from the rear end to the opening side at the connection end. Has a two-step large diameter part that expands in diameter, inserts the insertion end of the aluminum pipe into the two-step large diameter part, and positions the flange of the aluminum pipe at the opening-side large diameter part, A streak-shaped ridge that is deformed and bulges toward the inner surface of the copper pipe by applying a pressure that makes a round line in the circumferential direction from the outer peripheral surface of the body pipe at the overlapping portion of the circumferential surface of the flange and the copper pipe An adhesive portion is provided to bite into and crimp in a streak shape that goes around the circumferential surface.

[0008]

[Function] When pressure is applied while rotating the pressure roller from the outer peripheral surface of the large diameter portion of the copper pipe so as to make one round in the circumferential direction, the surface of the large diameter portion increases the pressure of the pressure roller. As it goes down, a streak-shaped groove is formed on the surface of the large-diameter portion in the circumferential direction, and it deforms and bulges into a streak-shaped ridge toward the inner surface of the large-diameter portion. The convex bulge that bulges toward the side bites into the circumferential surface of the flange of the aluminum pipe that is press-fitted into the large-diameter portion and press-contacts the circumferential surface of the aluminum to obtain a strong crimp. And since the flange part of the aluminum pipe is thick and has rigidity, it sufficiently receives the bite pressure contact of the streak-like ridges on the inner surface of the large diameter part, and the boundary between the aluminum pipe and the copper pipe is not visible. It can be crimped, and high airtightness and good connection of both can be obtained.

[0009]

EXAMPLES Examples will be described with reference to the drawings.
1 is a partially cutaway perspective view of an evaporator provided in a refrigerator of the present invention, FIG. 2 is an enlarged cross-sectional view of a main portion of a connecting end portion before insertion of an aluminum pipe and a copper pipe, and FIG. 3 is aluminum. Fig. 4 is an enlarged cross-sectional view of the main part of the pipe, where the tip of the pipe is inserted into the large diameter portion of the copper pipe and caulking is performed. A cross-sectional view showing a state where processing is performed by la,
FIG. 5 is an enlarged cross-sectional view of an essential part showing a crimping portion between the flange of the aluminum pipe and the large diameter portion of the copper pipe. The evaporator 1 of the refrigerator includes an aluminum fin 3 and an aluminum pipe 3 provided on the aluminum fin 3. In connection of the aluminum pipe 3 and the copper pipe 4 provided in the compressor (not shown), the aluminum pipe 3 is integrally formed with a flange 5 in the form of a ring collar that bulges and expands near the insertion end. This flange 5 has a desired thickness and rigidity,
The copper pipe 4 has a large-diameter portion 8 on the rear end side and a large-diameter portion 9 on the opening side that gradually increase in diameter through the steps 6 and 7 at the connection end, that is, the large-diameter portion on the opening side. 9 is formed to have a larger diameter than the large diameter portion 8 on the rear end side, and the tip of the aluminum pipe 3 of the evaporator 1 is inserted into the large diameter portion 8 on the rear end side so that the flange 5 of the aluminum pipe 3 has the step portion 7. Is inserted into the large diameter portion 9 on the opening side so as to come into contact with. Then, as shown in FIG.
The large diameter portion 9 on the opening side is adhered to the side surface of the flange 5, and the caulking 10 is applied so that the opening tip is adhered to the aluminum pipe 3 in a tubular shape having a predetermined length to connect the aluminum pipe 3 and the copper pipe 4, In this state, as shown in FIG. 4, a pressure roller 12 of a pressure roller of a three-roller type is attached to the overlapping portion 11 between the circumferential surface of the flange 5 of the aluminum pipe 3 and the copper pipe 4. When the pressure roller 12 is attached and rotated while moving the pressure roller 12 from the outer peripheral surface of the copper pipe 4 so as to make one round in the circumferential direction, the three pressure rollers 12 rotate and rotate with the flange 5. As the outer circumference of the overlapping portion 11 of the diameter portion 9 revolves and the pressure of the pressure roller 12 is increased, the inner surface of the overlapping portion 11 becomes a linear groove 13 in the circumferential direction on the surface of the overlapping portion 11. The streak-shaped ridge 14 is deformed and bulges toward the side,
By the method in which the ridges 14 bite into the circumferential surface of the flange 5 of the aluminum pipe 3 that is press-fitted into the large diameter portion 9 and press-contact with each other, the circle of the overlapping portion 11 of the large diameter portion 9 of the copper pipe 4 and the flange 5 of the aluminum pipe 3 is circled. Circumferentially around the circumferential surface and crimp to the streak.

Further, as shown in the enlarged view of FIG. 5, the ridge 14 of the overlapping portion 11 which is deformed and bulges under the pressure of the pressure roller 12 receives the pressure due to the biting of the ridge 14. The aluminum pipe 3 is pressure-bonded until the boundary with the circumferential surface of the flange 5 is not recognized, and good adhesion between the aluminum pipe 3 and the copper pipe 4 in the overlapping portion 11 is obtained.

The large-diameter portion 9 on the opening side of the copper pipe 4 is
The peripheral surface of the flange 5 of the aluminum pipe 3 is formed to have an inner diameter such that the large diameter portion 9 is press-fitted, and the copper pipe 4
It is preferable to form so that the pressure applied from the outer surface of the large diameter portion 9 can be satisfactorily transmitted to the circumferential surface of the flange 5.

Further, in this embodiment, the evaporator 1 of the refrigerator is used.
Although the connection between the aluminum pipe 3 and the copper pipe 4 of the compressor has been described, it is needless to say that the invention is not particularly limited to the connection of the refrigerator pipe and can be widely applied to the connection of the aluminum pipe and the copper pipe. Also,
The pressurizing device is not limited to the three-roller type as used in this embodiment as long as it can apply a circumferential pressure to the surface of the pipe.

Since the present invention has the above-mentioned structure, when connecting the copper pipe and the aluminum pipe, the aluminum pipe is press-fitted into the aluminum pipe by providing the aluminum pipe with a flange having thickness and rigidity. Mechanical pressure is applied from the surface of the copper pipe at the overlapping portion of the flange and the copper pipe,
Plastic deformation is applied to the pressurizing part to press it, deforming and bulging toward the inner surface of the copper pipe and making a ridge that goes around in the circumferential direction to obtain good crimping by biting into the circumferential surface of the aluminum flange, and at the connection part. The airtightness is secured, a firm and reliable connection can be obtained, processing is easy, and it can be provided at a low cost.

[Brief description of drawings]

FIG. 1 is a partially cutaway perspective view of an evaporator according to the present invention.

FIG. 2 is an enlarged cross-sectional view of a main part of a connection end portion before inserting an aluminum pipe and a copper pipe of the present invention.

FIG. 3 is an enlarged sectional view of an essential part of the aluminum pipe of the present invention, which is inserted into the large-diameter portion of the copper pipe and is caulked.

FIG. 4 is a cross-sectional view showing a state in which the aluminum pipe of the present invention is inserted into a large diameter portion of a copper pipe and the overlapping portion of the flange is processed by a pressure roller.

FIG. 5 is an enlarged cross-sectional view of an essential part showing a crimping portion between the flange of the aluminum pipe of the present invention and the large diameter portion of the copper pipe.

[Explanation of symbols]

 1 Evaporator 2 Aluminum fin 3 Aluminum pipe 4 Copper pipe 5 Flange 6 Step 7 Step 8 Large diameter 9 Large diameter 10 Caulking 11 Polymerization 12 Pressure roller 13 Recessed groove 14 Convex ridge

Claims (2)

[Claims] 1. An aluminum pipe is integrally formed with a bulging and expanding annular flange-shaped flange near the insertion end, and the connecting end of the copper pipe is gradually expanded in diameter from the rear end to the opening side.
Form a large-diameter portion of the step, insert the tip of the aluminum pipe into the large-diameter portion of the deep end of the copper pipe, insert the flange into the large-diameter portion on the opening side of the copper pipe, and crimp the opening of the copper pipe. Connect the aluminum pipe to the copper pipe, and in this state, apply pressure so that it makes a round line in a circumferential direction from the outer peripheral surface of the copper pipe where the flange pipe of the aluminum pipe and the body pipe overlap. A method of connecting pipes, wherein the inner surface side of the pressurizing portion of the copper pipe is deformed and bulged in a streak shape and crimped into a streak shape that goes around the circumferential surface of the flange of the aluminum pipe. 2. The aluminum pipe has a bulging flange-shaped flange near the insertion end, and the copper pipe has a two-stage large diameter at the connecting end that gradually expands from the rear end toward the opening side. A diameter portion, the insertion end of the aluminum pipe is inserted into the large diameter portion of the two stages, the flange of the aluminum pipe is located at the large diameter portion of the opening side of the copper pipe, At the overlapping part with the copper pipe, a pressure that makes a round line in the circumferential direction from the outer peripheral surface of the body pipe is applied and the streaky ridges that deform and bulge toward the inner surface side of the copper pipe go around the circumferential surface of the aluminum pipe. A structure of a connecting portion of a pipe, which is characterized in that an adhesive portion for biting into and crimping in a streak shape is provided.