JP2015199074A - Welding method of compressor vessel and manufacturing method of compressor using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a welding method of a compressor vessel capable of forming a circumferential weld with high fatigue strength while preventing an occurrence of incomplete penetration at the start of welding, and a manufacturing method of a compressor using the same.SOLUTION: There is provided a method of welding circumferentially-shaped circumferential welds 64 and 65 between a trunk 61 of a closed vessel 60 of a compressor, and an upper lid part 62 and a lower lid part 63 for closing an opening of the trunk part 61. TIG welding is performed for a part in a circumferential direction of a boundary, and MAG welding is performed for the whole circumference of the boundary with the part in a circumferential direction for which the TIG welding is performed as a welding starting end.

Description

  The present invention relates to a compressor container welding method and a compressor manufacturing method using the same.

As a welding method of circumferential welding used for welding of a hermetic container of a compressor, consumable electrode type MAG welding is mainly used. MAG welding is a type of arc welding and is a welding method in which metals are joined together by utilizing a discharge phenomenon in the air. In MAG welding, the weld is protected from the atmosphere by a mixed gas of Ar and CO ₂ or the like.

  One of the other welding methods is non-consumable electrode type TIG welding. In this method, an arc is generated between a tungsten electrode attached to a TIG welding torch and a base material, and welding is performed using arc heat. In TIG welding, the weld is protected from the atmosphere by an inert gas such as Ar.

JP 58-163574 A

  FIG. 6 shows a circumferential welding process for a sealed container of a compressor using the MAG welding method. When circumferentially welding the barrel 101 and the upper lid 102 of the sealed container, first, at the MAG welding start portion 103, the MAG welding wire 105 fed from the MAG welding torch 104 and the base material (the barrel 101 and the upper lid). An arc is generated with the unit 102). The MAG welding wire 105 and the base material are melted by the high heat generated thereby, and the MAG welding bead portion 106 is formed in the circumferential welded portion.

  FIG. 7 is a cross-sectional view of the MAG welding bead portion 106, and FIG. 8 is a cross-sectional view of the MAG welding start portion 103. In consumable electrode type welding such as MAG welding, as shown in FIG. 7, the base metals and the MAG welding wire 105 are completely melted to form the MAG welding bead portion 106. However, since there is no preheating at the start of welding, as shown in FIG. 8, in the MAG welding start portion 103, the melted MAG welding wire 105 is solidified on the base material before the base material melts. End up. Since the MAG welding wire 105 solidified on the base material blocks heat input, a poor penetration portion 107 is likely to occur at the MAG welding start portion 103.

  The closed container of the compressor is subjected to pressure due to repeated operation and stop in addition to extremely high pressure inside the compressor during operation, and thus changes in shape between the cylindrical shape and the barrel shape. As a result, a particularly repeated stress is applied to the circumferential weld of the sealed container. Therefore, when stress concentrates on the poor penetration part 107, a crack progresses from the poor penetration part 107, and the fatigue failure of the circumferential welded part occurs at an earlier stage than expected.

  On the other hand, in a non-consumable electrode type welding method such as TIG welding, no preheating is required, so no penetration failure occurs at the welding start portion. However, since the welding speed of TIG welding is low, if the entire circumferential weld is welded by TIG welding, it takes a very long time, and the productivity of the compressor is significantly reduced.

In recent years, in order to prevent global warming, the demand for an air conditioner using an R32 refrigerant having a low global warming potential and a heat pump type hot water supply apparatus using CO ₂ gas as a refrigerant is increasing. R32 refrigerant is slightly flammable. Furthermore, the characteristics of the CO ₂ gas, CO ₂ gas to high pressure more internal compressor in the case of using the refrigerant. For this reason, it is required to prevent fatigue failure at the circumferential welded portion of the sealed container and to improve the airtightness of the compressor.

  The present invention has been made in order to solve the above-described problems, and can prevent a poor penetration at the start of welding and can form a circumferential welded portion with high fatigue strength. It aims at providing the manufacturing method of the compressor using it.

  A method for welding a compressor container according to the present invention is a method of welding a circumferential boundary between a body part of a compressor container and a lid part that closes an opening part of the body part, the boundary being TIG welding is performed on a part of the circumferential direction of the part, the part subjected to the TIG welding is used as a welding start end part, and MAG welding is performed on the entire circumference of the boundary part It is.

  Moreover, the manufacturing method of the compressor based on this invention uses the said welding method of a compressor container, It is characterized by the above-mentioned.

  According to the present invention, since the welding start end portion of MAG welding can be melted in advance by TIG welding, it is possible to prevent poor penetration at the start of MAG welding and to form a circumferential weld portion having high fatigue strength in the compressor vessel. can do.

It is sectional drawing which shows schematic structure of the compressor manufactured by Embodiment 1 of this invention. It is a figure which shows the example of the flow of the process in the welding method of the compressor container which concerns on Embodiment 1 of this invention. In the welding method of the compressor container which concerns on Embodiment 1 of this invention, it is a figure which shows the state of the boundary part between the trunk | drum 61 and the upper cover part 62 when TIG welding is complete | finished. In the welding method of the compressor container which concerns on Embodiment 1 of this invention, it is a figure which shows the state of the boundary part between the trunk | drum 61 and the upper cover part 62 after MAG welding is complete | finished and a welding part solidifies. It is a figure which shows schematic structure of the welding apparatus used with the welding method of the compressor container which concerns on Embodiment 2 of this invention. It is a figure which shows the circumference welding process of the airtight container of the compressor using a MAG welding method. 3 is a cross-sectional view of a MAG weld bead portion 106. FIG. 3 is a cross-sectional view of a MAG welding start portion 103. FIG.

Embodiment 1 FIG.
A method for welding a compressor container and a method for manufacturing a compressor using the compressor container according to Embodiment 1 of the present invention will be described. FIG. 1 is a cross-sectional view showing a schematic configuration of a compressor manufactured according to the present embodiment. This compressor is a part of the components of a refrigeration cycle used in an air conditioner or a hot water supply device. In the present embodiment, a rolling piston type hermetic compressor is illustrated. In the following drawings including FIG. 1, the dimensional relationship and shape of each component may differ from the actual ones.

  As shown in FIG. 1, the compressor includes a compression mechanism unit 10 that compresses refrigerant sucked from the outside, an electric motor unit 50 that drives the compression mechanism unit 10, and a sealed container that houses the compression mechanism unit 10 and the electric motor unit 50. 60 (an example of a compressor container). Refrigerating machine oil (not shown) is stored at the bottom of the sealed container 60. The sealed container 60 includes a barrel portion 61 having a cylindrical shape, an upper lid portion 62 that blocks an opening portion above the barrel portion 61, and a lower lid portion 63 that blocks an opening portion below the barrel portion 61. Yes. A circumferential boundary portion (circumferential weld portion 64) between the trunk portion 61 and the upper lid portion 62, and a circumferential boundary portion (circumferential weld portion 65) between the trunk portion 61 and the lower lid portion 63. ) Is circumferentially welded by a welding method described later.

  The electric motor unit 50 includes a stator 51 and a rotor 52. The outer peripheral portion of the stator 51 is fixed to the inner peripheral surface of the trunk portion 61. A crankshaft 53 is fitted into the rotor 52. The crankshaft 53 is formed with an eccentric portion 54 that is eccentric in one direction.

  The compression mechanism 10 is disposed in the cylinder 20, the upper and lower ends of the cylinder 20, and is accommodated in the cylinder 20 and the main bearing 11 and the sub-bearing 12 that also serve as end plates of the cylinder 20, and the eccentric portion 54 is fitted therein. And a rolling piston 22. Although not shown, a vane that divides the inner circumferential space of the cylinder 20 into a suction chamber and a compression chamber is inserted into the vane groove of the cylinder 20.

  The compressor is provided adjacent to the outside of the hermetic container 60, and stores the low-pressure refrigerant flowing from the outside and separates the refrigerant into gas and liquid, and the refrigerant gas in the suction muffler 40 is sealed in the hermetic container 60. A suction pipe 41 for sucking in, a suction hole (not shown) for guiding the refrigerant gas sucked through the suction pipe 41 to a suction chamber in the cylinder 20, and a high-pressure refrigerant gas compressed in the compression chamber are sealed. A discharge hole (not shown) for discharging into the space in the container 60 and a discharge pipe 42 for discharging high-pressure refrigerant gas discharged into the space in the sealed container 60 to the outside are provided.

  In the compressor configured as described above, when the rotor 52 rotates, the crankshaft 53 fitted in the rotor 52 rotates, and the eccentric portion 54 rotates as the crankshaft 53 rotates. As the eccentric portion 54 rotates, the rolling piston 22 rotates and slides inside the cylinder 20. That is, the rolling piston 22 rotates eccentrically along the inner peripheral surface of the cylinder 20. As a result, the refrigerant gas is sucked into the suction chamber in the cylinder 20 from the suction pipe 41, and the refrigerant gas is compressed in the compression chamber in the cylinder 20. The high-pressure refrigerant gas compressed in the compression chamber is discharged into the space inside the sealed container 60 and discharged from the discharge pipe 42 to the outside of the sealed container 60.

  Next, a method for welding the compressor container and a method for manufacturing a compressor using the same will be described. When manufacturing the compressor, the compression mechanism section 10 and the electric motor section 50 are fixed to the inner peripheral side of the trunk section 61, and then the boundary section (fitting section) between the trunk section 61 and the upper lid section 62, And the boundary part (fitting part) between the trunk | drum 61 and the lower cover part 63 is welded by circumferential welding, respectively, and the inside of the airtight container 60 is sealed.

  FIG. 2 shows an example of a process flow in the compressor container welding method according to the present embodiment. In FIG. 2, the structure which looked at the trunk | drum 61 and the upper cover part 62 used as the airtight container 60 of a compressor in the axial direction is shown. Hereinafter, although the process of welding the boundary portion between the body portion 61 and the upper lid portion 62 will be described as an example, the same flow applies to the step of welding the boundary portion between the body portion 61 and the lower lid portion 63. Done in When circumferentially welding the boundary portion between the body portion 61 and the upper lid portion 62, first, the TIG welding process shown in FIG. 2A is performed, and thereafter (for example, immediately after the end of the TIG welding process), FIG. The MAG welding process shown in (b) is performed. That is, in this embodiment, hybrid circumferential welding using TIG welding and MAG welding is performed.

  As shown in FIG. 2A, the welding apparatus used in the TIG welding process has a TIG welding torch 71 and a TIG welding power source 72. In the TIG welding process, first, an arc is generated from the TIG welding torch 71 at the boundary portion between the body portion 61 and the upper lid portion 62. Then, as shown by the circular arc arrow, the body 61 and the upper lid 62 are rotated in the counterclockwise direction in the drawing, and TIG is applied to a part of the boundary direction between the body 61 and the upper lid 62 in the circumferential direction. Welding (welding of base materials) is performed.

  FIG. 3 shows a state of the boundary portion between the body portion 61 and the upper lid portion 62 at the time when the TIG welding is finished. As shown in FIG. 3, the TIG welding execution part 73 is formed in a part of the circumferential direction of the boundary part. At this time, the TIG welding execution part 73 is still in a molten state. One end in the circumferential direction of the TIG welding execution portion 73 is a welding start end portion 73a where TIG welding is started, and the other end in the circumferential direction is a welding end portion 73b where TIG welding is finished. The circumferential length of the TIG welded portion 73, that is, the weld length A in the circumferential direction of TIG welding is set to be 1/3 or less of the circumferential length of the entire circumference of the boundary portion between the trunk portion 61 and the upper lid portion 62. .

  Then, a workpiece | work is conveyed to a MAG welding process.

  As shown in FIG. 2B, the welding apparatus used in the MAG welding process includes a MAG welding torch 81, a MAG welding wire feeding device 82, and a MAG welding power source 83. In the MAG welding process, first, an arc is generated from the MAG welding torch 81 in a part of the TIG welding construction portion 73 (in this example, the welding start end portion 73a) in the boundary portion between the body portion 61 and the upper lid portion 62. Let And the trunk | drum 61 and the upper cover part 62 are rotated in the counterclockwise direction in the figure, and MAG welding is performed on the boundary part between the trunk | drum 61 and the upper cover part 62 from on the TIG welding construction part 73. FIG. MAG welding is continuously performed after the TIG welding construction part 73 and at least on the entire circumference of the boundary part. In this example, after the MAG welding of the entire circumference of the boundary portion is completed, the wrapping is further performed by about 20 to 40 mm. Here, in this example, the welding start end 73a of TIG welding and the welding start end of MAG welding are matched, and the welding direction (rotation direction) is also matched between TIG welding and MAG welding. It is not always necessary to match. That is, a portion other than the welding start end portion 73a in the TIG welding execution portion 73 may be a MAG welding start end portion, or the welding direction may be reversed between TIG welding and MAG welding.

  FIG. 4 shows a state of the boundary portion between the body portion 61 and the upper lid portion 62 after the MAG welding is finished and the welded portion is solidified. As shown in FIG. 4, a circumferential weld 64 is formed by MAG welding around the entire boundary. A welded portion 64a which is a part of the circumferential welded portion 64 is a portion where MAG welding has been performed from above the TIG welding execution portion 73 (a portion where both TIG welding and MAG welding have been performed). The other part of the circumferential weld 64 is a part where only MAG welding is performed.

  As described above, the compressor container welding method according to the present embodiment includes the body 61 of the sealed container 60 (an example of the compressor container), the upper lid 62 and the lower lid that close the opening of the body 61. It is the method of welding the circumferential boundary part (circumferential welding part 64, 65) between the parts 63, Comprising: TIG welding is performed with respect to a part of circumferential direction among boundary parts, and TIG welding is performed MAG welding is performed on the entire circumference of the boundary portion with a part of the welding start end portion.

  Thereby, since the base materials of the part used as the welding start end part of MAG welding can be previously fuse | melted by TIG welding, the penetration defect at the time of MAG welding start can be prevented. Thereby, since generation | occurrence | production of the poor penetration part which can become a starting point of fatigue failure can be prevented, the fatigue strength of a compressor container can be improved and the durability and airtightness of a compressor can be improved. Moreover, since the airtightness of the compressor can be improved, safety can be further improved even when a slightly flammable gas such as R32 is used as the refrigerant.

  The compressor container welding method according to the present embodiment is characterized in that the circumferential weld length A of TIG welding is set to 1/3 or less of the entire circumference of the boundary portion.

  Since the welding speed of TIG welding is about 1/3 of the welding speed of MAG welding, the cycle time when TIG welding is performed at 1/3 of the entire circumference of the boundary is MAG welding on the entire circumference of the boundary. It is equivalent to the cycle time when it is performed. Therefore, the increase in the cycle time of the welding process can be minimized by setting the weld length in the circumferential direction of TIG welding to 1/3 or less of the entire circumference of the boundary portion. Therefore, the weld bead can be efficiently formed without adversely affecting the productivity of the compressor.

Embodiment 2. FIG.
A method for welding the compressor container according to Embodiment 2 of the present invention will be described. In the first embodiment, TIG welding is used as a pre-process, and MAG welding is used as a post-process. In the present embodiment, TIG welding and MAG welding are performed in the same process.

  FIG. 5 is a diagram showing a schematic configuration of a welding apparatus used in the compressor container welding method according to the present embodiment. In addition, about the component which has the function and effect | action same as Embodiment 1, the same code | symbol is attached | subjected and the description is abbreviate | omitted. As shown in FIG. 5, in the welding apparatus used in the present embodiment, a TIG welding torch 71 is arranged at a position preceding the welding direction, and a MAG welding torch 81 is arranged at a position to follow.

  In the welding process, first, an arc is generated from the TIG welding torch 71 at the boundary portion between the body portion 61 and the upper lid portion 62, and TIG welding is started. Then, as shown by the arc arrow, the body 61 and the upper lid 62 are rotated in the counterclockwise direction in the drawing, and when the welding start end of TIG welding comes to just below the MAG welding torch 81, MAG welding is performed on the welding start end. An arc is generated from the torch 81 and MAG welding is started. TIG welding stops when the weld length becomes, for example, 1/3 of the entire circumference of the boundary. That is, the MAG welding is performed from the top of the TIG welded part from the beginning of the MAG welding to 1/3 of the entire circumference of the boundary. Thereafter, the entire circumference of the boundary is welded only by MAG welding. After MAG welding of the entire circumference of the boundary portion is completed, for example, wrapping is performed by about 20 to 40 mm.

  According to the present embodiment, as in the first embodiment, since MAG welding is performed from the top of the TIG welding construction portion at the start of MAG welding, it is possible to prevent penetration failure at the start of MAG welding. In addition, according to the present embodiment, TIG welding with a low welding speed can be suppressed to a minimum welding length, and therefore an increase in cycle time can be minimized.

Other embodiments.
The present invention is not limited to the above embodiment, and various modifications can be made.
For example, in the above embodiment, a rolling piston type compressor is taken as an example, but the present invention can be applied to other compressors such as a scroll type compressor.

  In addition, the above embodiments and modifications can be implemented in combination with each other.

  DESCRIPTION OF SYMBOLS 10 Compression mechanism part, 11 Main bearing, 12 Sub bearing, 20 Cylinder, 22 Rolling piston, 40 Suction muffler, 41 Suction pipe, 42 Discharge pipe, 50 Electric motor part, 51 Stator, 52 Rotor, 53 Crankshaft, 54 Eccentricity Part, 60 airtight container, 61 trunk part, 62 upper lid part, 63 lower lid part, 64, 65 circumferential welded part, 64a welded part, 71 TIG welding torch, 72 TIG welding power source, 73 TIG welding applied part, 73a welding start end Part, 73b welding end part, 81 MAG welding torch, 82 MAG welding wire feeding device, 83 MAG welding power source, 101 trunk, 102 upper lid part, 103 MAG welding starting part, 104 MAG welding torch, 105 MAG welding wire, 106 MAG weld bead, 107 poor penetration.

Claims (3)

A method of welding a circumferential boundary between a body portion of a compressor container and a lid portion that closes an opening of the body portion,
TIG welding is performed on a part of the boundary portion in the circumferential direction,
The compressor container welding method, wherein the part subjected to the TIG welding is used as a welding start end portion, and MAG welding is performed on the entire circumference of the boundary portion.   2. The welding method for a compressor container according to claim 1, wherein a welding length in a circumferential direction of the TIG welding is set to 1/3 or less of an entire circumference of the boundary portion.   A compressor manufacturing method using the compressor container welding method according to claim 1.

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