JPH0882460A - Pipe connecting method and structure of pipe connecting part - Google Patents

Abstract

PURPOSE: To enable two pipes to be press fitted to each other in such a way that they may not be removed from each other by a method wherein an aluminum pipe is press fitted to a copper pipe and a pressure is applied from an outer circumferential surface of the copper pipe to its circumferential direction so as to make a full surrounding of it in a stripe manner. CONSTITUTION: A large diameter part 5 is formed at the extremity end of a copper pipe 4 and one end of an aluminum pipe 3 of an evaporator is press fitted into a deep end of the large diameter part 5. Under this state, pressurizing rollers 6 of a pressurizing device of a three-roller type are installed at overlapped portions between the copper pipe 4 and the aluminum pipe 3 and then the pressurizing rollers 6 are rotationally moved from the outer circumferential surface of the large diameter part 5 of the copper pipe 4 so as to make a full surrounding of the pipe. With such an arrangement as above, three pressurizing rollers 6 are rotated around the outer circumference of the large diameter part 5 while they are rotated by themselves and they may become stripe-like recessed grooves 7 in a circumferential direction at the surface of the large diameter part 5 as the pressure of the pressuring rollers 6 is increased, resulting in that stripe-like projections 8 are deformed and bulged out toward the inner surface of the large diameter part 5 and then the projections 8 are engaged and press contacted with the surface of the aluminum pipe 3 to be press fitted.

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 press an aluminum pipe into a copper pipe and apply mechanical pressure from the surface of the copper pipe at the overlapping portions of the copper pipe. , A pipe connecting method and a connecting structure thereof, in which the pressurizing portion is plastically deformed and press-contacted with each other Is provided.

[0006]

In order to achieve the above object, a pipe connecting method according to the present invention comprises forming a cylindrical large-diameter portion of a predetermined length at one end of a copper pipe, While press-fitting one end of the aluminum pipe into the section, while rotating the pressure roller of the pressure roller of the three-roller type so as to make one round in the circumferential direction from the outer peripheral surface of the copper pipe in this state. It is characterized in that the inner surface side of the pressurizing portion of the copper pipe is deformed and bulged in a streak shape and pressed against the aluminum pipe to press the copper pipe and the aluminum pipe into a streak shape that makes one round in the circumferential direction. How to connect pipes.

Further, in the structure of the connecting portion of the pipe according to the present invention, a cylindrical large diameter portion having a predetermined length is formed at one end of the copper pipe, and one end of the aluminum pipe is press-fitted into the large diameter portion, A streaky pressure is applied in the circumferential direction from the outer peripheral surface of the copper pipe to deform it toward the inner surface of the copper pipe and swells into the aluminum pipe and bites into the aluminum pipe. A plurality of circumferentially streaky crimping portions are provided at a predetermined interval at a position where the large-diameter portion of the copper pipe and the insertion end portion of the aluminum pipe overlap with each other due to the deformed and bulging ridges, and they are integrally bonded. It is a thing.

The pressure roller is provided with two pressure portions, one at the rear end and the opening of the large diameter portion, or one at each of the rear end, the center and the opening. In addition, the pressurizing section has two rows or three rows at the same pitch as one set, and there are two locations at the rear end and the opening of the large diameter portion, or at the rear end, the central portion, and the opening. Part 3
It is preferable to provide them in places.

[0009]

[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 ridge bulging to the side digs into the surface of the aluminum pipe press-fitted into the large-diameter portion and press-contacts the surface of the aluminum to obtain a pressure bond between the two. Then, on the inner surface side of the aluminum pipe, a streak-shaped projection strip is formed that makes a round in the circumferential direction and is deformed and bulged by the bite pressure contact of the strip-shaped projection strip on the inner surface of the large diameter portion. By the bite of the ridge bulging toward the inner surface side of such a large diameter portion, the aluminum pipe is prevented from coming off from the copper pipe, the adhesion between the two is maintained, and a reliable connection between the two can be obtained. .

The pressure roller is provided with two pressure portions, one at each of the rear end and the opening of the large-diameter portion, or at each of the rear end, the center, and the opening. Alternatively, by providing two or three articles as a set, the two are firmly and surely connected.

[0011]

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, and FIG. 2 is a pressure roller for processing a superposed portion in which a tip of an aluminum pipe is inserted into a large diameter portion of a copper pipe. FIG. 3 is an enlarged cross-sectional view of a main part showing a crimping portion between an aluminum pipe and a large diameter portion of a copper pipe, and an evaporator 1 of a refrigerator has an aluminum fin 2 and an aluminum pipe 3 provided thereon. When connecting the aluminum pipe 3 of the evaporator 1 and the copper pipe 4 provided to the compressor (not shown), a large-diameter cylindrical portion 5 having a predetermined length is formed at the tip of the copper pipe 4. Then, one end of the aluminum pipe 3 of the evaporator 1 is press-fitted to the deep end of the large diameter portion 5. In this state, a pressure roller 6 of a pressure roller type pressurizing device is attached to the overlapping portion of the copper pipe 4 and the aluminum pipe 3 from the outer peripheral surface of the large diameter portion 5 of the copper pipe 4. When pressure is applied while rotating the pressure roller 6 so as to make one revolution in the circumferential direction, the three pressure rollers 6 revolve around the outer circumference of the large diameter portion 5 while rotating, and the pressure roller 6 is rotated. As the pressure of the la 6 is increased, a streak-shaped concave groove 7 is formed on the surface of the large-diameter portion 5 in the circumferential direction, and a streak-shaped convex shape 8 is deformed and bulged toward the inner surface side of the large-diameter portion 5. By the method in which the strip 8 bites into the surface of the aluminum pipe 3 that is press-fitted into the large-diameter portion 5 and press-contacts, the large-diameter portion 5 of the copper pipe 4 and the aluminum pipe 3 make one round in the circumferential direction and are crimped to the streak.

As shown in the enlarged view of FIG. 4, the ridge 8 of the large-diameter portion 5 which is deformed and bulges under the pressure of the pressure roller 6 has no boundary with the aluminum pipe 3. The pressurizing portion of the aluminum pipe 3 which has been pressed by the above and has received the pressure due to the biting of the convex strip 8 of the large-diameter portion 5 makes a round line in the circumferential direction in which the aluminum pipe 3 deforms and bulges toward the inner surface side of the aluminum pipe 3. The ridge 9 is formed, and the ridge 9 bites into the ridge 8 to form a structure in which the aluminum pipe 3 prevents the copper pipe 4 from coming off from the large-diameter portion 5.

As shown in FIG. 3, the pressure applied by the pressure roller 6 is divided into two positions, that is, the rear end side position of the large diameter part 5 and the opening side position.
It is preferable to provide one line at each position, or, as shown in FIG. 5, provide one line at each of the three positions of the rear end side, the central part, and the opening side. Further, as shown in FIG. 6, two sets are formed at the same pitch, and two positions are provided at the rear end side position and the opening side position of the large diameter portion 5, or as shown in FIG. It is preferable to provide two strips at each of the three positions of the side, the center, and the side of the opening. Further, as shown in FIG. 8, the pressurizing roller 6 pressurizes at two positions, that is, the rear end side position and the opening side position of the large diameter part 5 with one set of three threads as one set. Alternatively, as shown in FIG. 9, it is preferable to provide three strips at each of three positions of the rear end side, the central portion, and the opening side.

In this embodiment, the connection between the aluminum pipe of the evaporator of the refrigerator and the copper pipe of the compressor has been described. However, the invention is not particularly limited to the refrigerator and widely used for connecting the aluminum pipe and the copper pipe. It goes without saying that it can be applied. 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.

[0015]

Since the present invention has the above-mentioned structure,
When connecting a copper pipe and an aluminum pipe, press the aluminum pipe into the copper pipe, apply mechanical pressure from the surface of the copper pipe at the overlapping part of each other, give plastic deformation to the pressurizing part, and press-contact the inner surface of the pipe. By forming ridges that deform and bulge to the side and make a round in the circumferential direction, they are crimped so that they do not come out of each other and cannot be removed, a solid and reliable connection that secures the airtightness of the connection part is obtained, and processing is also easy Therefore, it can be provided at 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 a front view showing a pressurizing device installed at a connection portion of the evaporator of the present invention.

FIG. 3 is a cross-sectional view of a main part of a connection portion of the evaporator of the present invention.

FIG. 4 is an enlarged sectional view of an essential part showing a bonded state of a connection part of an evaporator of the present invention.

FIG. 5 is a cross-sectional view of an essential part of the evaporator of the present invention, in which three pressurizing parts are provided for one line at the connecting part.

FIG. 6 is a cross-sectional view of a main part of the evaporator of the present invention in which two pressurizing parts are provided for two lines in the connecting part.

FIG. 7 is a cross-sectional view of a main part of the evaporator of the present invention in which three pressurizing parts are provided at two points for the connecting part.

FIG. 8 is a cross-sectional view of a main part of the evaporator of the present invention, in which two pressurizing parts are provided at three points in the connecting part.

FIG. 9 is a cross-sectional view of a main part of the evaporator of the present invention, in which a connecting part is provided with three pressurizing parts for three lines.

[Explanation of symbols]

 1 Evaporator 2 Aluminum fin 3 Aluminum pipe 4 Copper pipe 5 Large diameter part 6 Pressure roller 7 Recessed groove 8 Convex ridge 9 Convex ridge

Claims (2)

[Claims] 1. A copper pipe having a cylindrical large-diameter portion having a predetermined length formed at one end, and one end of the aluminum pipe being press-fitted into the large-diameter portion. A pressure is applied so that the copper pipe and the aluminum pipe are circularly curved, and the inner surface side of the pressurizing portion of the copper pipe is deformed and bulged in a linear manner and pressed against the aluminum pipe to make a line that makes one round in the circumferential direction between the copper pipe and the aluminum pipe. A method for connecting pipes, which is characterized by being crimped into a shape. 2. A large-diameter cylindrical portion having a predetermined length is formed at one end of the copper pipe, and one end of the aluminum pipe is inserted into the large-diameter portion to form a streak shape in the circumferential direction from the outer peripheral surface of the copper pipe. A copper pipe is formed by applying a pressure to make a round and deforming and bulging toward the inner surface of the copper pipe, biting into the aluminum pipe and making pressure contact, and a ridge that deforms and bulges toward the inner surface of the aluminum pipe due to the biting of the ridge. The connection of pipes characterized in that the large-diameter part and the insertion end of the aluminum pipe are overlapped with each other, and a streak-like crimping part that makes one round in the circumferential direction is provided at a predetermined interval Structure of the department.