JP6925517B2 - Circumferential welding method and circumferential welding equipment - Google Patents

Description

The present invention relates to a circumferential welding method and a circumferential welding device for a cylindrical container in a closed compressor.

The closed compressor used for air conditioning and hot water supply has a pressure vessel in which a compression mechanism unit for compressing the refrigerant gas and a motor unit for driving the compression mechanism unit are housed. The pressure vessel has a cylindrical portion and two lid portions that close the openings at both ends of the cylindrical portion, and has a cylindrical shape as a whole. An annular portion inserted into the cylindrical portion is formed on each of the two lid portions. Then, the end surface of the cylindrical portion and the outer peripheral surface of the annular portion of the lid portion are joined by circumferential welding.

For example, in the welding of the closed compressor described in Patent Document 1, a preflow time of the shield gas is provided before the start of welding, and a time is provided for forming an initial pool without rotating the work at the start of welding. .. Patent Document 1 states that this prevents arc breakage, spatter generation, welding defects, and the like at the start of welding, and makes it possible to obtain a good arc start and a weld bead start end.

Japanese Unexamined Patent Publication No. 2003-33872

However, in the assembly process of the closed type compressor, it is general that a temporary welding for fixing parts and a heating process are performed before the start of the circumferential welding. Therefore, the initial temperature of the work when starting the circumferential welding of the closed compressor has a temperature difference from room temperature to 100 ° C., for example, depending on the elapsed time from the heating step. If the initial temperature of the work is low and the preheating is not sufficient, it is difficult to obtain the initial bead from being dissolved in the base metal. Therefore, the welding method of Patent Document 1 has a problem that the penetration of the initial bead into the base metal varies depending on the initial temperature of the work, and the strength reliability as a closed compressor cannot be obtained.

The present invention has been made to solve the above problems, and an object of the present invention is to provide a circumferential welding method and a circumferential welding device that can obtain a sealed compressor having high strength reliability.

The circumferential welding method according to the present invention is a circumferential welding method of a closed type compressor having a cylindrical container and a pair of lid caps provided at both ends of the cylindrical container, and is a method of circumferential welding with the end face of the cylindrical container. Based on the work temperature acquisition step for acquiring the temperature of the lap fillet joint portion formed on the outer peripheral surface of the lid cap before the start of welding and the temperature acquired in the work temperature acquisition step, the lap fillet and welding condition determining step of determining a welding condition of the meat joint, based on the welding condition determining welding conditions determined in step, seen including a welding step of performing welding of the lap fillet joint, the welding In the condition determination step, the current value of the welding current supplied to the initial welding before the steady welding of the lap fillet joint portion is started is determined under the condition smaller than the welding current in the steady welding. ..

Further, the circumferential welding device according to the present invention is a circular welding device of a closed type compressor having a cylindrical container and a pair of lid caps provided at both ends of the cylindrical container, and is the circumferential welding device of the cylindrical container. A temperature sensor for measuring the temperature of the lap fillet joint portion formed by the end surface and the outer peripheral surface of the lid cap and a control panel are provided, and the control panel is provided with the lap fillet joint portion by the temperature sensor. A work temperature acquisition unit that acquires the temperature before the start of welding, a welding condition determination unit that determines the welding conditions of the lap fillet joint portion based on the temperature acquired by the work temperature acquisition unit, and the welding. based on the selected welding condition by condition determining unit, possess a welding controller for controlling welding of the lap fillet joint, the welding condition determining unit, the constant welding of the lap fillet joint is initiated The current value of the welding current supplied to the initial welding before the welding is determined under a condition smaller than the welding current in the steady welding .

According to the circumferential welding method and the circumferential welding apparatus according to the present invention, there is no variation in the penetration of the initial bead solidified in the molten pool into the base metal. Therefore, the strength of the fillet circumference welded portion formed in the lap fillet joint portion does not vary among individuals, and the strength reliability of the closed compressor can be improved.

It is a schematic block diagram of the circumferential welding apparatus which concerns on embodiment of this invention. It is a figure which shows typically the vertical cross section of the closed type compressor. It is a functional block diagram of the circumferential welding apparatus which concerns on embodiment of this invention. It is a figure which shows the current pattern of the welding current in the circumferential welding method which concerns on embodiment of this invention together with the rotation angle of a work. It is a graph which shows the relationship between the work temperature and the welding current suitable for melting of the initial bead into a base metal. It is a flowchart which shows the procedure of the welding process of the compressor which concerns on embodiment of this invention. It is a flowchart which shows the processing procedure of the circumferential welding of the compressor which concerns on embodiment of this invention.

Hereinafter, the circumferential welding method and the embodiment of the circumferential welding apparatus in the present invention will be described in detail with reference to the drawings. The present invention is not limited to the embodiments described below. Further, in the drawings below, the size and shape of each component may differ from the actual device.

Embodiment.
FIG. 1 is a schematic configuration diagram of a circumferential welding device according to an embodiment of the present invention. The circumferential welding device 1 includes a control panel 10, a rotating device 11, a welding wire feeding device 12, a welding wire 13, a welding wire feeding cable 14, a welding power source 15, a feeding cable 16A, and a feeding cable 16B. Further, the circumferential welding device 1 includes a gas supply source 17, a temperature sensor 18, a sensor cable 19, a welding torch 25, and a gas hose 26. The control panel 10 controls the circumferential welding device 1 as a whole.

A cylindrical container 20 is mounted on the rotating device 11. The rotating device 11 is a device capable of positioning, fixing, and rotating the cylindrical container 20 in an arbitrary posture, and operates according to a command from the control panel 10. The cylindrical container 20 is a member that houses parts of the compression mechanism portion of the closed-type compressor, which will be described later, parts of the motor portion, and the like. Both ends of the cylindrical container 20 are open, and a pair of upper lid cap 21 and lower lid cap 22 are provided. The upper lid cap 21 is press-fitted into one end of both ends of the cylindrical container 20, and the lower lid cap 22 is press-fitted into the other end of both ends of the cylindrical container 20. The cylindrical container 20, the upper lid cap 21, and the lower lid cap 22 are made by molding a steel plate material. The overlap fillet joint portion 23 is formed by the end surface of one end portion of the cylindrical container 20 and the outer peripheral surface of the upper lid cap 21. The overlap fillet joint portion 24 is formed by the end surface of the other end portion of the cylindrical container 20 and the outer peripheral surface of the lower lid cap 22.

The welding torch 25 is connected to the welding wire feeding device 12 via the welding wire feeding cable 14. In FIG. 1, the welding torch 25 is arranged at the lap fillet joint portion 23.

The welding power supply 15 is a welding wire melting type welding power supply that alternately and repeatedly outputs a pulse current higher than the critical current and a base current lower than the critical current. The welding power supply 15 is a DC pulse welding power supply of a constant current control method, a constant voltage control method, or a control method in which constant current control and constant voltage control are used in combination. The welding torch 25 is connected to the welding power source 15 via the power supply cable 16A, and the rotating device 11 is connected via the power supply cable 16B. The welding current required for pulse arc welding is supplied by a command from the control panel 10.

The gas supply source 17 supplies the shield gas to the tip of the welding torch 25 via the gas hose 26. The gas supply source 17 mainly supplies Ar gas used for welding steel materials, and supplies MAG gas in which about 10 to 20% of _{CO 2 gas is mixed.} The gas supply source 17 is, for example, a gas cylinder or a gas tank.

While rotating the cylindrical container 20 with the rotating device 11, in the atmosphere of the shield gas supplied from the gas supply source 17, between the welding wire 13 and the lap fillet joint portion 23, or between the welding wire 13 and the lap fillet joint Pulse arc welding is performed with the portion 24.

The temperature sensor 18 is a sensor for measuring the temperature of the lap fillet joint portion 23 and the lap fillet joint portion 24. The temperatures of the lap fillet joint portion 23 and the lap fillet joint portion 24 measured by the temperature sensor 18 are transmitted to the control panel 10 via the sensor cable 19. The temperature sensor 18 may be a contact type sensor or a non-contact type sensor.

FIG. 2 is a diagram schematically showing a vertical cross section of a closed compressor. The closed compressor 100 includes the above-mentioned cylindrical container 20, an upper lid cap 21, and a lower lid cap 22. Further, the sealed compressor 100 has a compression mechanism unit 110 that compresses the refrigerant and a motor unit 120 that drives the compression mechanism unit 110. The upper lid cap 21 is provided at the upper opening in FIG. 2 of both ends of the cylindrical container 20. The lower lid cap 22 is provided at the opening of the lower end of FIG. 2 at both ends of the cylindrical container 20. The compression mechanism unit 110 and the motor unit 120 are housed in the cylindrical container 20. The compression mechanism unit 110 is located below the cylindrical container 20, and the motor unit 120 is located above the cylindrical container 20.

The motor unit 120 is composed of, for example, a DC motor. The motor unit 120 has a stator 121 and a rotor 122. The stator 121 is fixed to the inner peripheral surface of the cylindrical container 20. The rotor 122 is arranged inside the stator 121. Power is supplied to the stator 121 from the glass terminal 101 fixed to the upper lid cap 21.

The compression mechanism 110 has a cylinder 111 and a crankshaft 112. The cylinder 111 is a hollow member having a cylindrical shape, and both ends in the axial direction are open. Bearings 113 are provided on the upper end side in FIG. 2 of both ends of the cylinder 111 in the axial direction. Bearings 114 are provided on the lower end side in FIG. 2 of both ends of the cylinder 111 in the axial direction.

The crankshaft 112 has a cylinder 111 inserted through it. The crankshaft 112 is rotated by the driving force of the rotor 122 of the motor unit 120. A rolling piston (not shown) is provided in the cylinder 111. The rolling piston is fitted to the eccentric shaft of the crankshaft 112 and rotates eccentrically along the inner peripheral surface of the cylinder 111. In the cylinder 111, a compression chamber (not shown) is formed by the inner peripheral surface of the cylinder 111 and the outer peripheral surface of the rolling piston.

Further, the closed compressor 100 has a suction pipe 102, a gas-liquid separator 103, and a discharge pipe 104. The suction pipe 102 is connected to an evaporator (not shown) of a refrigeration cycle in which the closed compressor 100 is a component. The refrigerant flowing out of the evaporator flows into the gas-liquid separator 103 through the suction pipe 102, and is guided from the gas-liquid separator 103 to the cylinder 111. The discharge pipe 104 is connected to a condenser (not shown) of a refrigeration cycle in which the closed compressor 100 is a component. The high-pressure refrigerant in the cylindrical container 20 is sent to the refrigeration cycle via the discharge pipe 104.

A lap fillet circumference weld 105 is formed in the above-mentioned lap fillet joint portion 23 formed by the upper end portion of the cylindrical container 20 and the outer peripheral surface of the upper lid cap 21. The lap fillet circumference welded portion 106 is formed in the above-mentioned lap fillet joint portion 24 formed by the end portion of the lower mold of the cylindrical container 20 and the outer peripheral surface of the lower lid cap 22.

FIG. 3 is a functional block diagram of the circumferential welding device according to the embodiment of the present invention. The control panel 10 has a work temperature acquisition unit 30, a welding condition determination unit 31, and a welding control unit 32. Each function of the work temperature acquisition unit 30, the welding condition determination unit 31, and the welding control unit 32 is realized by the control panel 10.

The work temperature acquisition unit 30 acquires the temperature of the work of pulse arc welding, that is, the cylindrical container 20 to be welded. More specifically, the data of the temperature of the lap fillet joint portion 23 and the temperature of the lap fillet joint portion 24 measured by the temperature sensor 18 are input to the work temperature acquisition unit 30. The welding condition determination unit 31 determines the welding conditions for pulse arc welding based on the temperature data of the lap fillet joint 23 and the temperature of the lap fillet joint 24 acquired by the work temperature acquisition unit 30. The welding control unit 32 outputs a control signal of the welding power source 15 based on the welding conditions determined by the welding condition determination unit 31.

In the present embodiment, the control panel 10 may be dedicated hardware or a CPU (Central Processing Unit) that executes a program stored in the memory. The CPU is also referred to as a processing unit, an arithmetic unit, a microprocessor, a microcomputer, a processor, or a DSP (Digital Signal Processor).

When the control panel 10 is dedicated hardware, the control panel 10 corresponds to, for example, a single circuit, a composite circuit, a programmed processor, a parallel programmed processor, an ASIC, an FPGA, or a combination thereof. .. The functions of the work temperature acquisition unit 30, the welding condition determination unit 31, and the welding control unit 32 may be realized by the processing circuit, or the functions of the respective parts may be collectively realized by the processing circuit.

When the control panel 10 is a CPU, the functions of the work temperature acquisition unit 30, the welding condition determination unit 31, and the welding control unit 32 are realized by software, firmware, or a combination of software and firmware. Software and firmware are written as programs and stored in memory. The control panel 10 realizes the functions of each part by reading and executing the program stored in the memory. That is, the control panel 10 includes a memory for storing a program in which a step corresponding to a function of each unit is eventually executed when executed by the control panel 10. The steps corresponding to the functions of each part will be described later. Further, it can be said that these programs cause the computer to execute the procedures and methods of the work temperature acquisition unit 30, the welding condition determination unit 31, and the welding control unit 32. Here, the memory corresponds to, for example, a non-volatile or volatile semiconductor memory such as RAM, ROM, flash memory, EPROM, and EPROM, or a magnetic disk, flexible disk, optical disk, compact disk, mini disk, DVD, or the like. do.

It should be noted that some of the functions of the work temperature acquisition unit 30, the welding condition determination unit 31, and the welding control unit 32 may be realized by dedicated hardware and part by software or firmware.

In this way, the control panel 10 can realize the functions of the work temperature acquisition unit 30, the welding condition determination unit 31, and the welding control unit 32 by hardware, software, firmware, or a combination thereof.

FIG. 4 is a diagram showing the current pattern of the welding current in the circumferential welding method according to the embodiment of the present invention together with the rotation angle of the work. The upper graph and the lower graph of FIG. 4 show the passage of time on the horizontal axis, the upper graph of FIG. 4 shows the rotation angle of the workpiece in circumferential welding on the vertical axis, and the lower graph of FIG. 4 shows the vertical axis. The current value supplied from the welding power source 15 is taken to the shaft.

At t0, the current supply from the welding power source 15 is started, and pulse arc welding is started. t0 to t1 are the initial welding and the period during which the molten pool is formed. The rotation angle of the work is maintained at 0 ° and does not rotate, and a welding current smaller than the welding current at the time of steady welding is supplied from the welding power source 15 to form a molten pool.

t1 to t2 are transition periods from initial welding to steady welding. The work is rotated to a rotation angle r1, and the current value of the welding current supplied from the welding power source 15 is increased to the current value a2 at the time of steady welding.

t2 to t3 are periods during which steady welding is performed. During the period of t2 to t3, the current of the current value a2 is supplied from the welding power source 15, and the work is rotated to the rotation angle r2. r2 is about 360 °. In this way, the initial bead in which the work rotates once and the molten pool formed by the initial welding is solidified is positioned on the welding wire 13.

t3 to t4 are periods during which the lap process is executed in the initial bead. During the period from t3 to t4, the work is rotated from the rotation angle r2 to the rotation angle r3. r3 is about 375 °. During this time, the current supplied from the welding power source 15 is lowered from the current value a2 at the time of steady welding to the current value a3, and the initial bead is wrapped.

At t4, the rotation of the work is stopped, the current supply from the welding power source 15 is stopped, and the pulse arc is stopped.

In the present embodiment, there are three patterns of welding current supplied from the welding power source 15 during one round welding of the lap fillet joint portion 23 and the lap fillet joint portion 24. In the first pattern, the current value from t0 to t1 is set to the third current value a1-1, and the current value rises from the third current value a1-1 to the current value a2 for steady welding between t1 and t2. do. Then, the current value from t2 to t3 is maintained at the current value a2, the current value drops to the current value a3 at t3, the current value from t3 to t4 is maintained at the current value a3, and the current supply is stopped at t4. It is a pattern. In the second pattern, the current value from t0 to t1 is set to the second current value a1-2, and the current value rises from the second current value a1-2 to the current value a2 for steady welding between t1 and t2. do. Then, the current value from t2 to t3 is maintained at the current value a2, the current value drops to the current value a3 at t3, the current value from t3 to t4 is maintained at the current value a3, and the current supply is stopped at t4. It is a pattern. In the third pattern, the current value from t0 to t1 is set to the first current value a1-3, and the current value rises from the first current value a1-3 to the current value a2 for steady welding between t1 and t2. do. Then, the current value from t2 to t3 is maintained at the current value a2, the current value drops to the current value a3 at t3, the current value from t3 to t4 is maintained at the current value a3, and the current supply is stopped at t4. It is a pattern. The first current value a1-3, the second current value a1-2, and the third current value a1-1 are such that the third current value a1-1 <the second current value a1-2 <the first current value a1-3. There is a relationship.

Here, a welding current suitable for melting the initial bead into the base metal in pulse arc welding will be described. FIG. 5 is a graph showing the relationship between the work temperature and the welding current suitable for melting the initial bead into the base metal. As shown in FIG. 5, a relatively high welding current is suitable for melting the initial bead into the base metal when the work temperature is relatively low, and relatively high when the work temperature is relatively high. Low welding current is suitable. When the work temperature is less than the first threshold value T1, the highest first current value a1-3 shown in FIG. 4 is suitable as the current value of the welding current for forming the initial bead. When the work temperature is equal to or higher than the second threshold value T2, the lowest third current value a1-1 shown in FIG. 4 is suitable as the current value of the welding current for forming the initial bead. When the work temperature is equal to or higher than the first threshold value T1 and lower than the second threshold value T2, the current value of the welding current for forming the initial bead is higher than the third current value a1-1 and the first current value a1-3. The second current value a1-2 shown in FIG. 4, which is lower than that, is suitable.

In the present embodiment, the first threshold value T1 is set to, for example, 30 ° C. as the work has passed from the heating step up to that point and is approaching room temperature, and the second threshold value T2 is from the heating step. Assuming that the passage of time is short and the work temperature is high, it is set to, for example, 60 ° C. When the work has passed the heating process up to that point and is approaching room temperature, for example, when the welding line is started up, when the welding line is restarted by step change, and when the welding line is restored from a line trouble. Etc. are assumed. In the present embodiment, one of the first pattern, the second pattern, and the third pattern shown in FIG. 4 is selected based on the temperature of the work before the circumferential welding is started.

FIG. 6 is a flowchart showing the procedure of the welding process of the compressor according to the embodiment of the present invention. In step S1, the cylindrical container 20 in which the upper lid cap 21 and the lower lid cap 22 are press-fitted to both ends, which is the work of the circumferential welding of the present embodiment, is carried in. In step S2, the cylindrical container 20 is fixed to the rotating device 11 of the circumferential welding device 1. In step S3, the circumferential welding process by the circumferential welding device 1 is executed. In step S4, the cylindrical container 20 is released from the rotating device 11 and removed from the circumferential welding device 1, and in step S5, the cylindrical container 20 to which the upper lid cap 21 and the lower lid cap 22 are welded is carried out.

FIG. 7 is a flowchart showing a processing procedure for circumferential welding of the compressor according to the embodiment of the present invention. The circumferential welding process shown in FIG. 7 is a process executed by the control panel 10 in step S3 of FIG.

Step S10 is a work temperature acquisition step. In step S10, the work temperature acquisition unit 30 is formed by the temperature of the work in circumferential welding, that is, the outer peripheral surface of the upper lid cap 21 and the end portion of the cylindrical container 20 based on the data input from the temperature sensor 18. Acquires the temperature of the overlapping fillet joint portion 23.

In steps S11 to S15, the welding condition determination unit 31 determines the welding conditions based on the work temperature acquired by the work temperature acquisition unit 30. The welding condition is a current pattern of the current supplied from the welding power source 15 shown in FIG. In step S11, the welding condition determination unit 31 checks whether the temperature of the lap fillet joint portion 23 is less than the first threshold value T1. When the temperature of the lap fillet joint portion 23 is less than the first threshold value T1, the process proceeds to step S12. In step S12, the welding condition determination unit 31 selects the third pattern described with reference to FIG. 4 as the welding condition.

When the temperature of the lap fillet joint portion 23 is equal to or higher than the first threshold value T1, the process proceeds to step S13. In step S13, the welding condition determination unit 31 checks whether the temperature of the overlap fillet joint portion 23 is equal to or higher than the second threshold value T2. When the temperature of the lap fillet joint portion 23 is equal to or higher than the second threshold value T2, the process proceeds to step S14. In step S14, the welding condition determination unit 31 selects the first pattern described with reference to FIG. 4 as the welding condition. When the temperature of the lap fillet joint portion 23 is less than the second threshold value T2, the process proceeds to step S15. The case where the process proceeds to step S15 is a case where the temperature of the overlap fillet joint portion 23 is equal to or higher than the first threshold value T1 and lower than the second threshold value T2. In step S15, the welding condition determination unit 31 selects the second pattern described with reference to FIG. 4 as the welding condition.

In this way, the temperature of the lap fillet joint portion 23 before the start of circumferential welding is compared with the first threshold value T1 and the second threshold value T2, and welding conditions suitable for the temperature of the lap fillet joint portion 23 are selected.

When the selection of the welding conditions in steps S11 to S15 is executed and the welding conditions are determined, the process proceeds to step S16. In step S16, the welding control unit 32 starts supplying the current from the welding power source 15, and outputs a control signal instructing to start the gas output by the gas supply source 17 to the welding power source 15. As a result, the welding arc is started, and the circumferential welding of the cylindrical container 20 and the upper lid cap 21 is started. From step S17 to step S20, the welding control unit 32 controls the circumferential welding based on the welding conditions determined by the welding condition determination unit 31.

In step S17, the processes t0 to t1 shown in FIG. 4 are executed. When the welding condition determination unit 31 selects the first pattern, the welding control unit 32 outputs a control signal instructing to supply a current at the third current value a1-1 to the welding power source 15. When the welding condition determination unit 31 selects the second pattern, the welding control unit 32 outputs a control signal instructing to supply a current at the second current value a1-2 to the welding power source 15. When the welding condition determination unit 31 selects the third pattern, the welding control unit 32 outputs a control signal instructing to supply a current at the first current value a1-3 to the welding power source 15. As a result, a molten pool is formed.

In step S18, the processes of t1 to t2 shown in FIG. 4 are executed. In step S18, the welding control unit 32 outputs a control signal instructing the welding power source 15 to increase the supplied current to the current value a2 and to rotate the cylindrical container 20 to the rotation angle r1 by the rotating device 11. do. When the first pattern is selected, the current supplied from the welding power source 15 rises from the third current value a1-1 to the current value a2. When the second pattern is selected, the current supplied from the welding power source 15 increases from the second current value a1-2 to the current value a2. When the third pattern is selected, the current supplied from the welding power source 15 increases from the first current value a1-3 to the current value a2. As a result, the circumferential welding shifts to steady welding.

In step S19, the processes of t2 to t3 shown in FIG. 4 are executed. In step S19, the welding control unit 32 outputs a control signal instructing the welding power source 15 to maintain the supplied current at the current value a2 and to rotate the cylindrical container 20 to the rotation angle r2 by the rotating device 11. do. As a result, steady welding is continued.

In step S20, the processes of t3 to t4 shown in FIG. 4 are executed. In step S20, the welding control unit 32 sends a control signal instructing the current to be supplied from the current value a2 to the current value a3 and the rotating device 11 to rotate the cylindrical container 20 to the rotation angle r3. Output to 15. As a result, the wrapping treatment is performed on the initial bead formed by solidifying the molten pool formed in step S17.

Then, in step S21, the welding control unit 32 outputs a control signal instructing to stop the supply of the current and stop the output of the gas by the gas supply source 17 to the welding power source 15. As a result, the welding arc is stopped, and the circumferential welding of the cylindrical container 20 and the upper lid cap 21 is completed. As a result, the fillet circumference welded portion 105 shown in FIG. 2 is formed in the lap fillet joint portion 23 shown in FIG.

In the above description, the case where the fillet circumference welded portion 105 is formed in the lap fillet joint portion 23 has been described as an example. When the fillet circumference welded portion 106 is formed in the lap fillet joint portion 24 formed by the end portion of the cylindrical container 20 and the outer peripheral surface of the lower lid cap 22, the circumferential weld is executed in the same procedure. ..

Generally, in circumferential welding, preheating is insufficient in a range of less than 10 mm in the circumferential direction of the work from the welding start point. Further, the state of preheating in this range varies depending on the elapsed time from the start-up of the circumferential welding device. Therefore, when the welding current supplied from the start of welding of the cylindrical container 20, the upper lid cap 21 and the lower lid cap 22 to the formation of the molten pool is controlled by a single default value, the molten pool solidifies as the base material of the initial bead. There is variation among individuals in the integration into. Therefore, the strengths of the fillet circumference welded portion 105 and the fillet circumference welded portion 106 vary, and the strength reliability of the sealed compressor 100 cannot be obtained.

On the other hand, according to the present embodiment, a molten pool is formed from the start of welding based on the work temperature before the start of circumferential welding, that is, the temperatures of the lap fillet joint portion 23 and the lap fillet joint portion 24. The current value of the supplied current is changed. Therefore, there is no variation in the dissolution of the initial bead in which the molten pool is solidified into the base metal. Therefore, the strengths of the fillet circumference welded portion 105 and the fillet circumference welded portion 106 do not vary among individuals. That is, according to the present embodiment, the strength reliability of the sealed compressor 100 can be improved.

In the present embodiment, there are three welding current patterns, but the present invention is not limited to this. If the welding current pattern is two or more, it may be increased or decreased as necessary.

In the present embodiment, a preset pattern is selected to determine the current value of the welding current, but the present embodiment is not limited to this. An equation relating to the work temperature and the optimum welding current may be set, and the current value of the current supplied from the welding power source 15 may be determined based on the calculation result of the equation.

In the present embodiment, the joint shape of the cylindrical container 20 and the upper lid cap 21 and the joint shape of the cylindrical container 20 and the lower lid cap 22 have a structure of a lap fillet joint, but the present invention is not limited to this. In the case of other butt joint structures, the initial bead welding conditions are similarly selected.

1 Welding device, 10 Control panel, 11 Rotating device, 12 Welding wire feeder, 13 Welding wire, 14 Welding wire feeder cable, 15 Welding power supply, 16A power supply cable, 16B power supply cable, 17 Gas supply source, 18 Temperature sensor, 19 Sensor cable, 20 Cylindrical container, 21 Upper lid cap, 22 Lower lid cap, 23 Laminated fillet joint, 24 Laminated fillet joint, 25 Welding torch, 26 Gas hose, 30 Work temperature acquisition part, 31 Welding conditions Determining part, 32 Welding control part, 100 Sealed compressor, 101 Glass terminal, 102 Suction pipe, 103 Gas-liquid separator, 104 Discharge pipe, 105 Laminated fillet circumference weld, 106 Laminated fillet circumference weld, 110 compression mechanism part, 111 cylinder, 112 crank shaft, 113 bearing, 114 bearing, 120 motor part, 121 stator, 122 rotor, T1 first threshold, T2 second threshold, a1-1 third current value, a1- 2 Second current value, a1-3 First current value, a2 current value, a3 current value, r1 rotation angle, r2 rotation angle, r3 rotation angle.

Claims (4)

A circumferential welding method for a closed compressor having a cylindrical container and a pair of lid caps provided at both ends of the cylindrical container.
A work temperature acquisition step for acquiring the temperature of the lap fillet joint formed between the end surface of the cylindrical container and the outer peripheral surface of the lid cap before the start of welding, and
A welding condition determination step for determining the welding condition of the lap fillet joint portion based on the temperature acquired in the work temperature acquisition step, and a welding condition determination step.
Based on the welding condition the determined welding condition determining step, see contains a welding step of performing welding of the lap fillet joint,
In the welding condition determination step, the current value of the welding current supplied to the initial welding before the steady welding of the lap fillet joint portion is started is determined under the condition smaller than the welding current in the steady welding. Peripheral welding method. In the welding condition determination step, the temperature of the lap fillet joint portion is compared with the first threshold and the second threshold higher than the first threshold, and when the temperature is less than the first threshold, in the initial welding. The first current value set as the current value of the welding current to be supplied, and the current value of the welding current to be supplied in the initial welding when the temperature is equal to or more than the first threshold value and less than the second threshold value. The current value of the welding current is selected from the second current value and the third current value set as the current value of the welding current supplied in the initial welding when the second threshold value or more is obtained. The circumferential welding method according to claim 1. A circumferential welding device for a closed compressor having a cylindrical container and a pair of lid caps provided at both ends of the cylindrical container.
A temperature sensor that measures the temperature of the lap fillet joint formed by the end surface of the cylindrical container and the outer peripheral surface of the lid cap, and
Equipped with a control panel
The control panel
A work temperature acquisition unit that acquires the temperature of the overlap fillet joint portion before the start of welding by the temperature sensor, and
A welding condition determining unit that determines the welding conditions of the lap fillet joint portion based on the temperature acquired by the work temperature acquiring unit, and a welding condition determining unit.
Based on the selected welding condition by the welding condition determining unit, possess a welding controller for controlling welding of the lap fillet joint,
The welding condition determining unit determines the current value of the welding current supplied to the initial welding before the start of steady welding of the lap fillet joint portion under a condition smaller than the welding current in the steady welding. Welding equipment. The welding condition determining unit compares the temperature of the lap fillet joint portion with the first threshold and the second threshold higher than the first threshold, and when the temperature is less than the first threshold, in the initial welding. The first current value set as the current value of the welding current to be supplied, and the current value of the welding current to be supplied in the initial welding when the temperature is equal to or more than the first threshold value and less than the second threshold value. The current value of the welding current is selected from the second current value and the third current value set as the current value of the welding current supplied in the initial welding when the second threshold value or more is obtained. The circumferential welding device according to claim 3.

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