KR20080028715A - Method for manufacturing piston for swash plate type compressor - Google Patents

Abstract

A method for manufacturing a piston for a swash plate type compressor is provided to reduce the manufacturing cost by adopting a magnetic pulse welding method instead of an electron beam welding or friction welding method that has been used for welding of individual parts of a piston, and welding copper rings to piston heads without using a Teflon coating method. A method for manufacturing a piston for a swash plate type compressor comprises: a forming step of separately forming a body part(20) in which a swash plate receiving groove(24) and a shoe placing groove(28) are formed, and cylindrical hollow piston heads(30) of which one side faces are opened; and a piston welding step of welding weld joints of the body part and the piston heads formed by the forming step by magnetic pulse welding. The method further comprises a copper ring welding step of welding copper rings(40) to outer peripheral surfaces of the piston heads by magnetic pulse welding.

Description

METHODS FOR MANUFACTURING PISTON FOR SWASH PLATE TYPE COMPRESSOR}

1 is a cross-sectional view of a swash plate compressor used in an air conditioner for automobiles.

Figure 2 is a perspective view of each of the parts after the molding step of the swash plate compressor piston manufacturing method according to the present invention.

(A), (b), (c) is a top view and sectional drawing of a magnetic pulse welding apparatus.

Figure 4 (a), (b), (c) is a perspective view and a cross-sectional view of the piston completed by the swash plate compressor piston manufacturing method according to the present invention.

Reference numerals for the main components of the invention

10: piston

20: body part

24: Saphan Home

28: Shoe landing groove

30: piston head

40: copper ring

60: Saphan

80: turn coil

The present invention relates to a method for manufacturing a piston of a swash plate compressor used in an automobile air conditioner, and more particularly, to a method for manufacturing a hollow piston for a compressor that can increase the compression efficiency of the compressor due to its low weight and very low inertia. .

The compressor constituting the air conditioner of the automobile is selectively received by the power of the engine delivered through the pulley by the intermittent action of the electronic clutch to compress the refrigerant in the gaseous phase supplied from the evaporator to a state of high temperature and high pressure that is easy to liquefy and condenser It is a device to discharge. In general, a swash plate compressor used in an automobile air conditioner is configured to inhale a refrigerant gas transported after evaporation is completed from an evaporator to a state of high temperature and high pressure that is easily liquefied and discharged to a condenser. The swash plate type compressor includes a plurality of pistons mounted with a shoe interposed along a swash plate by rotating a disk-shaped swash plate, which is fixed to a driving shaft that is driven by an engine, and rotates with the driving shaft according to the rotation of the driving shaft. As the linear reciprocating motion is performed in the plurality of cylinders formed in the cylinders, the refrigerant is sucked and discharged.

The piston of such a swash plate type compressor has a disadvantage in that the structure is complicated and the weight is heavy. However, the piston of the swash plate compressor The shape of the cylinder is good for mounting and durability of the vehicle, high compression efficiency and operating efficiency. In addition, because of the large number of cylinders, the torque is less fluctuated during rotation, as well as mechanically harmonized due to the advantages of low vibration and noise and high speed operation. In order to reduce the weight of the piston, it is common to manufacture the piston head hollow.

The hollow piston is a hollow part of the cylindrical part that occupies most of the piston volume. The hollow piston has a very light weight to volume, so that the inertia generated in proportion to the weight during reciprocating is very small. Therefore, when applied to a compressor, the compression performance of the compressor can be significantly increased compared to the case of applying a solid piston that is relatively heavy and generates large inertia during reciprocation.

However, in the case of the hollow piston, since an integral raw material piston having a hollow portion cannot be formed by a die casting or forging process, there is an inherent difficulty in manufacturing that a hollow portion must be formed by dividing and molding them into two members. For this reason, the hollow piston has a disadvantage in that the manufacturing cost is high and the defect rate due to manufacturing complexity is very high. Nevertheless, since the hollow piston has the advantage of having a very large effect of improving the compressor efficiency, various methods of manufacturing the hollow piston for the compressor that can more easily manufacture the hollow piston have been proposed.

In the conventional hollow piston manufacturing method, the piston 10 is separated into a body part 20 and a piston head 30, and then molded, and then machined and coupled to each other in a state of a material, and then the body part 20 and the vacuum state. The piston head 30 is fixed by electron beam welding to form the piston 10.

Such a conventional method for manufacturing a hollow piston for a compressor requires precise processing of each joining surface of the body part 20 and the piston head 30 to be divided to form a hollow part, and the time required for welding is 10 seconds. It is relatively long more than this. In addition, since the assembly and processing procedures are difficult and complicated, the entire manufacturing process of the piston is considerably complicated, which leads to a low productivity and a high piston failure rate. In addition, since the electron beam welding, which mainly joins the piston body and the piston head, which is mainly made of aluminum-based alloy, must be carried out under a vacuum environment to prevent oxidation of the material, an expensive equipment that can perform electron beam welding after creating a vacuum environment is required. There is also a problem that the burden of equipment cost is excessive.

In addition, the piston manufactured by the conventional hollow piston manufacturing method has a low durability because it contains the fine holes generated in the electron beam welding process in the tissue, and the refrigerant and oil penetrate through the fine holes, and the amount of refrigerant and oil amount is insufficient. Had a problem causing the condition. In addition, when the fine holes generate a leak between the piston and the bore, and when the holes penetrate into and out of the hollow part, the refrigerant or oil is filled into the hollow part to increase the piston weight. There is also a problem that greatly reduces the.

In addition, the electron beam, but instead is also used by way of friction welding for joining by friction with the joint surfaces of the two divided material, the friction site bulge at the junction has a disadvantage should a polishing part.

An object of the present invention is to propose a piston manufacturing method of a new swash plate compressor for solving the disadvantages of the piston manufacturing method of the existing swash plate compressor. Specifically, it is proposed a new joining method that can replace the piston head and piston body bonding method and a method of lowering the manufacturing cost by replacing the Teflon coating.

In order to achieve the above object, the present invention provides a method for manufacturing a piston of a swash plate type compressor, wherein the body portion 20 having the swash plate receiving groove and the shoe seating groove is formed separately from the cylindrical hollow piston head 30 having one side open. Molding step of molding; And

It characterized in that it comprises a piston joining step of joining the joint portion of the body portion 20 and the piston head 30 processed by the forming step by magnetic pulse welding (Magnetic Pulse Welding).

In this case, it is preferable to further include a copper ring bonding step of bonding copper ring copper material to the outer circumferential surface of the piston head by magnetic pulse welding (Magnetic Pulse Welding).

Hereinafter, the piston manufacturing method of the swash plate compressor will be described in detail with reference to the accompanying drawings.

The swash plate compressor is divided into a variable type in which the inclination angle of the swash plate is variable and a fixed type in which the swash plate is fixed. The piston used in the compressor can be produced in a head and head type, depending on the number of piston heads, and the manufacturing method is substantially the same in the head and piston heads. Therefore, it is apparent that the description or the drawing of the piston manufacturing method of the swash plate compressor according to the present invention can be used for both types of pistons.

In the case of the conventional method for manufacturing a piston, as described above, there is a problem in that the joining method is a method using an electron beam or a friction method, and thus the joining time is long, and the manufacturing cost increases due to Teflon coating.

Figure 2 is a perspective view of each of the parts after the molding step of the swash plate compressor piston manufacturing method according to the present invention. The molding step of the piston manufacturing method according to the present invention is made by a forging process due to the characteristics of the parts requiring durability. In addition, the material of the piston is generally used aluminum-based alloy can lower the rotational load of the swash plate of the compressor. Lowering the rotating load of the swash plate is a method of increasing the efficiency of the compressor, and using a hollow piston with an empty piston head is also a method of increasing the efficiency of the compressor by lowering the rotating load.

As shown in FIG. 2, forming the body portion 20 includes forming the swash plate groove 24 and the shoe seating groove 28. The swash plate groove 24 is a space for accommodating the swash plate on which the shoe seated in the shoe seating groove 28 is mounted.

In order to manufacture the piston in a hollow, the piston head 30 is preferably molded to have a cup shape. And, as shown in Figure 2, the coupling portion of the body portion 20 and the piston head 30 is preferably molded so that one portion is inserted into the other side. That is, a method of forming a locking jaw at the coupling portion of the body portion 20 or the piston head 30 to widen the bonding portion may be used.

In the embodiment of the present invention shown in Figure 2, the joint portion of the body portion 20 is processed in the form inserted into the piston head (30). The operation of forming the locking jaw at the junction of the body portion of the forging process is completed by cutting.

In addition, although not shown in FIG. 2, the hollow part of the piston may be expanded by hollowing out the side of the body part along with a method of processing the inside of the piston head 30 in a hollow state. And, in the embodiment according to the present invention, in order to prevent friction between the piston and the inner surface of the compressor housing can be fitted with the copper ring 40 by forming a locking step in the piston head (30).

3 (a), (b) and (c) are a plan view and a cross-sectional view of a magnetic pulse welding device used in a joining method in a swash plate compressor piston manufacturing method according to the present invention. Magnetic pulse welding device is a useful joining method for joining dissimilar metals, and it is advantageous in that the welding time is very short. In terms of productivity and processing quality, it is superior to conventional electron beam welding or friction welding.

Figure 3 (a) is a plan view simplified the magnetic pulse welding device. When current flows from one end to a turn-shaped coil 80 having a place where a welding target can be positioned in the center, the current I flows in the circumferential direction.

The magnetic field is formed similarly to the solenoid by the current I flowing in the circumferential direction, and a magnetic field surrounding the turn coil in the vertical direction of the turn coil 80 is formed. A magnetic field having the same direction is formed inside the turn coil 80 in the shape of a disc, and a magnetic pressure is generated by magnetism therein. This magnetic pressure provides a compression force into the turn coil, and the welding object located at the center of the turn coil 80 is bonded in a very short time.

3 (b) and 3 (c) are cross-sectional views of the piston head 30 and the body portion 20 of the piston of the front and rear stages of the magnetic pulse welding process.

Bonding of the body portion 20 and the piston head 30, and the piston head 30 and the copper ring 40 by magnetic pulse welding may be performed in one bonding process. In other words, the bonding process and the coating process can be replaced by one process. In addition, the outer diameter of the coping ring 40 may be larger than the diameter of the piston head 30 and a portion where friction occurs in the compressor may also be limited to the outer surface of the coping ring.

In the conventional case, in addition to the teflon coating process, the process of polishing the friction surface is generally added, but according to the method of manufacturing the piston according to the present invention, since the friction part of the piston will be limited to the outer surface of the copper ring, The polishing step can be omitted.

Figure 4 (a), (b), (c) is a perspective view and a cross-sectional view of the piston of the swash plate compressor completed by the swash plate compressor piston manufacturing method according to the present invention. As already described, the manufacturing method of the compressor piston according to the present invention can be applied to the case of a double head piston as well as a single head piston.

Magnetic pulse welding used in the piston manufacturing method of the swash plate compressor according to the present invention can replace the electron beam welding or friction welding used in the conventional bonding of the individual components forming the piston. In addition, the production cost can be reduced by joining the copper ring to the piston head.

Claims (2)

In the manufacturing method of the piston of the swash plate compressor, A molding step of separately molding the body portion 20 having the swash plate accommodation groove and the shoe seating groove, and the cylindrical hollow piston head 30 having one side open; And Piston manufacturing of the swash plate compressor comprising a piston joining step of joining the joint portion of the body portion 20 and the piston head 30 processed by the forming step by magnetic pulse welding (Magnetic Pulse Welding) Way. The method of claim 1, The piston of the swash plate type compressor, characterized in that it further comprises a copper ring bonding step of bonding the copper ring (40) made of copper (copper) material to the outer circumferential surface of the piston head (30) by magnetic pulse welding (Magnetic Pulse Welding) Manufacturing method.

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