JP3770136B2 - Method for connecting segment coils used in motors - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a method for connecting segment coils used in a motor, and more particularly, to a method of welding a welding point of a segment coil and forming an insulating film on a welded portion.
[0002]
[Prior art]
A segment coil is used to facilitate the coiling process of the stator or rotor of the motor. FIG. 8 is a diagram showing a cross section of the stator 1 of the motor developed in the circumferential direction. The stator 1 is provided with a plurality of slots 3 for storing coils at a constant pitch. FIG. 8 shows, as an example, a case where one stator winding 5 is sequentially arranged every three slots 3 in so-called distributed winding. The segment coil 7A made of a substantially U-shaped insulated conductor with insulation coating has its both leg portions inserted into a slot 3 separated by three slots, both leg portions being bent, and has both end portions 9A and 9B as indicated by broken lines. It becomes a structure. Similarly, the segment coils 7B and 7C are arranged adjacent to each other, connect one end 9A of the segment coil 7A and one end 9C of the segment coil 7B, and connect the other end 9B of the segment coil 7A and the segment coil 7C. One end 9D is connected, and the segment coils 7B, 7A, and 7C are continuous.
[0003]
By repeating this once in the circumferential direction of the stator 1, one stator winding 5 is arranged in every three slots 3. By repeating this, a predetermined number of stator windings 5 are arranged in each slot, and the structure of the stator 1 using segment coils is obtained.
[0004]
9A to 9C show examples of the prior art regarding the method of connecting the end portions of such segment coils. In order to connect the end portions, as a pretreatment, a segment coil, for example, an enamel coating of enameled copper wire is peeled off at the end portions, and the end portions are aligned to be welded points.
[0005]
FIG. 9A is a diagram showing a welding process. For example, 48 rows in the circumferential direction and four 192 in total in the radial direction of each row are arranged on one surface of the annular stator 11. A welding torch 15 sequentially welds the welding points 13. The welding torch 15 is set at the first welding point, welding is performed, the position of the welding torch 15 is fixed as it is, the stator 11 is rotated, and the welding torch 15 is moved to the next welding point in the circumferential direction. Move relative to each other and perform the next welding. When 48 rounds of welding are completed in the circumferential direction, the welding torch 15 is moved in the radial direction and moved to the next welding point in the radial direction. Thereafter, this is repeated, and a total of 192 points are welded.
[0006]
FIG. 9B is a diagram illustrating a heating process, in which the stator 11 that has been welded is heated in a heating furnace 17 at, for example, 170 degrees C. for 4 hours.
[0007]
FIG. 9C is a diagram showing a melt adhesion step, in which the heated stator 11 is immersed in the powder immersion tank 19 and the thermosetting resin is melted and adhered to the welded portion 13. The powder immersion bath 19 has a porous partition plate 21 having, for example, a hole of several μm inside the bath, and the immersion portion 23 on the upper portion of the partition plate 21 has a characteristic that the melting point is around 100 degrees C. A thermosetting resin powder having a diameter of 10-30 μm, such as an epoxy resin, is supplied. When air is fed from the air inlet 25 at the lower part of the partition plate 21, the powder is appropriately rolled up and flows at the upper part of the partition plate 21. The heated stator 11 is moved to the upper part of the powder immersion bath 19 and moved down, and placed at a height at which the end of the segment coil is immersed in this flowing powder, so that the powder is above the melting point. Touch the heated end to melt and adhere.
[0008]
Thereafter, although not shown, the stator in which the thermosetting resin is melted and adhered to the end portions of the segment coils is heat-treated at a curing temperature or higher and thermally cured to form an insulating film at the end portions of the segment coils. In this way, the segment coils are connected.
[0009]
[Problems to be solved by the invention]
Thus, the segment coil used in the motor can be connected by the conventional segment coil connection method. However, in the prior art, since it is necessary to heat the entire welded stator, for example, about 4 hours are required for one heating time, work efficiency is poor, and a large number of heating facilities and electric power are required for mass production. did.
[0010]
An object of the present invention is to provide a segment coil connection method that solves the problems of the prior art, eliminates the need for heating equipment, and has high work efficiency.
[0011]
[Means for Solving the Problems]
The segment coil connection method according to the present invention focuses on the fact that only the end of the segment coil is required to be above the melting point of the thermosetting resin in order to melt and attach the thermosetting resin to the end of the segment coil. The change in the residual heat temperature due to the welding of the welded part was investigated, and this is based on the knowledge that the residual heat can be used under a certain condition.
[0012]
In FIG. 1, for example, 192 welding points of a stator using a segment coil of enamelled copper wire laminated with magnetic steel sheets having a diameter of about 30 cm, an inner diameter of about 20 cm, and a thickness of about 10 cm are shown. It is the figure which showed typically the change of the preheating temperature by welding in the room temperature atmosphere of the welding part when welding sequentially. The temperature of the welded part immediately after welding is determined by the melting point of the copper wire and reaches about 1000 ° C. Although the temperature of the welded portion rapidly decreases in a room temperature atmosphere, for example, about 5 minutes to decrease to the melt adhesion lower limit temperature of the epoxy resin powder, about 5 minutes, a temperature having a sufficient margin from the melt adhesion lower limit temperature, For example, it takes about 3 minutes to decrease to 180 ° C. This cooling curve is determined by the heat capacity around the segment coil, the heat flow path, and the like. If the stator is determined, it becomes a constant cooling curve. On the other hand, the time required for welding at 192 points is about 45 seconds, and the time required for the epoxy resin powder to melt and adhere is about 5 seconds.
[0013]
As described above, it has been clarified that the time required for welding and the time required for melt adhesion are sufficiently shorter than the time required for the preheating temperature to decrease from about 1000 ° C. immediately after welding to 100 ° C. which is the lower limit temperature for melt adhesion. Therefore, it is understood that the thermosetting resin can be melted and adhered within the meltable period until the preheating temperature due to the welding of the welded portion becomes a predetermined temperature or less according to the melting point of the thermosetting resin. It was.
[0014]
When welding is performed sequentially on the 192 points to be welded, the first welded portion is along the cooling curve i, the point A-B-C and the last welded portion are along the cooling curve b, Point D-E-F and temperature drop. As described above, there is a difference in temperature at each welding point, and if the amount of melt adhesion varies depending on the temperature, there is a possibility that a difference in the film thickness of the insulating film occurs. Therefore, in order to improve the film thickness uniformity, it is necessary to perform melt adhesion with a small temperature difference between the welded portions.
[0015]
In order to achieve the above object of the present invention, a segment coil connection method according to the present invention welds welding points of segment coils provided in a plurality of rows in the circumferential direction of the stator or rotor and a predetermined number in the radial direction, A method of connecting segment coils, in which an insulating film is formed by melting and adhering a thermosetting resin to the welded portion, wherein a welding torch moves relative to the stator or the rotor, and the welding points are sequentially arranged A welding process for welding, and a melt adhesion process for adhering the thermosetting resin within a possible melt adhesion period of a predetermined temperature or higher according to the melting point of the thermosetting resin, with a preheat temperature due to welding of the welded portion And a thermosetting step of heat-treating the attached thermosetting resin to form an insulating film.
[0016]
In the segment coil connection method according to the present invention, it is preferable that the predetermined temperature is 100 ° C. or more and 180 ° C. or less.
[0017]
In the segment coil connection method according to the present invention, it is preferable that the melt adhesion period is within three minutes from the start of the welding.
[0018]
Further, the segment coil connection method according to the present invention comprises welding a weld point of a segment coil provided in a plurality of rows in the circumferential direction of the stator or rotor and a predetermined number in the radial direction, and a thermosetting resin on the welded portion. A segment coil connecting method in which a welding torch moves in a radial direction of the stator or rotor, and a predetermined number of the welded points provided in the radial direction are sequentially formed. A radial row welding step for welding in a row and a preheating temperature due to welding of the welded portion within a weldable period of a predetermined temperature or more according to the melting point of the thermosetting resin, the welded portion in the radial direction Furthermore, it has a radial direction melt adhesion process for melting and adhering the thermosetting resin, and a thermosetting process for heat-treating the adhering thermosetting resin to form an insulating film.
[0019]
Further, the segment coil connection method according to the present invention comprises welding a weld point of a segment coil provided in a plurality of rows in the circumferential direction of the stator or rotor and a predetermined number in the radial direction, and a thermosetting resin on the welded portion. A segment coil connecting method in which a welding torch moves relative to the stator or the rotor and sequentially welds the welding points; and the welding An injection melt adhesion step of sequentially injecting the thermosetting resin to the welded portion within a possible melt adhesion period of a predetermined temperature or higher according to the melting point of the thermosetting resin, the residual heat temperature due to the welding of the portion; And heat-treating the attached thermosetting resin to form an insulating film.
[0020]
As described above, the segment coil connection method according to the present invention is a method in which the heat-curing is performed within the melt-adherable period until the preheating temperature due to welding of the welded portion is equal to or lower than a predetermined temperature corresponding to the melting point of the thermosetting resin. Since the adhesive resin is adhered, no heating equipment is required, and the segment coils can be connected with good work efficiency.
[0021]
Furthermore, since the welded points are sequentially welded and then the thermosetting resin is sequentially sprayed, after welding one welded point, the thermoset resin is sprayed onto one of the welded points and a sufficiently high residual heat temperature is maintained. Thus, melt adhesion can be performed, and the thickness of the insulating film between the welded portions can be made even more uniform.
[0022]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. The same elements as those in FIG. 9 are denoted by the same reference numerals and the description thereof is omitted. FIG. 2 is a flowchart for the first embodiment. As shown in FIG. 1, the first embodiment is a method in which the welded portion is fluidly immersed in the thermosetting resin during a period in which the temperature due to the residual heat of the welding is sufficiently higher than the lower limit temperature of the melt adhesion of the thermosetting resin. It is.
[0023]
STEP 51 is an initial position setting step for setting the position of the welding torch at the first welding point. For example, it is set to the position of the innermost welding point.
[0024]
STEP 53 is a sequential welding process shown in STEP 531 to STEP 539.
[0025]
STEP 531 is a one-point welding process. FIG. 3 shows a configuration in the vicinity of the welded point 13. The welding torch 15 is arranged at a slight distance below the welded point 13. The welded point 13 is a part in which the insulation coating of the segment coils 7A and 7B is peeled off, and the end is in contact with the welding ground claw 27 and is arranged. The welding ground claw 27 and the welding torch 15 In the meantime, a high voltage is applied from the high voltage source 29. Therefore, a discharge occurs between the welding torch 15 and the welded point 13, and the welded point 13 is melted and joined.
[0026]
The process of returning to STEP 531 again after STEP 531, STEP 533, and STEP 537 is a circumferential welding process. After the one-point welding process of STEP531, it is determined whether or not one round of welding in the circumferential direction of the stator 11, for example, 48 welds, has been completed in the STEP533 one-round welding completion determination process. Until 48 rounds are completed, the process proceeds to the circumferential movement step of STEP 537, the workpiece, in this case, the stator 11 is rotated in the circumferential direction by the distance between the welding points, and the welding torch 15 is connected to the next welded point 13. Is moved relatively. Instead of rotating the workpiece, the welding torch 15 may be moved. When the position of the welding torch 15 is set to the next welded point 13, the single point welding process of STEP 531 is resumed. Thus, the process of returning to STEP 531 again after STEP 531, STEP 533, and STEP 537 is repeated, and welding is sequentially performed in the circumferential direction.
[0027]
If it is determined in the step 533 one-round welding completion determination step that the welding for one round has been completed, in step 535 all-welding completion determination step, all the weldings, for example, 48 rounds of welding for four rows, a total of 192 weldings are performed. Determine if completed. Until the entire welding is completed, the process proceeds to the radial movement step of STEP 535, and the welding torch 15 is moved to the outer peripheral side by the distance between one welding point along the radial direction of the stator 11, and the next welding point 13 is reached. Move relative to the position of. When the position of the welding torch 15 is set to the next welding point 13, the process returns to STEP 531, and welding is sequentially performed again in the circumferential direction. This process is repeated, and when all the welding is completed, the welding process is finished, and the process proceeds to STEP55.
[0028]
STEP 55 is a melt adhesion step. When it is determined in STEP 535 that all welding has been completed, the welded portion of the stator 11 after the completion of welding is immersed in the powder immersion tank 19 to melt and adhere the thermosetting resin. It is an adhesion process. As already described with reference to FIG. 1, it is necessary to carry out the melt adhesion process within 3 minutes from the start of welding. For example, an epoxy resin powder having a melting point of about 100 ° C. is supplied to the powder immersion tank 19.
[0029]
STEP 57 is a thermosetting process in which the stator after the melt adhesion process is heated so as to satisfy the thermosetting condition, and the thermosetting resin that has been fused and adhered is thermally cured to form an insulating film. For example, heating is performed at 170 ° C. for 30 minutes.
[0030]
In this way, during the period in which the temperature due to the residual heat of the welding is sufficiently higher than the lower limit temperature of the melt adhesion of the thermosetting resin, the thermosetting resin is flow-immersed in the welded portion, the insulating film is formed, Connections can be made, production lead times can be greatly reduced, and equipment costs can be reduced.
[0031]
FIG. 4 is an explanatory diagram of the second embodiment. In this case, a predetermined number, for example, four welding points 13 arranged in a line in the radial direction of the stator 11 are sequentially welded to form a weld line. Thereafter, the small powder immersion tank 31 moves to the position of the weld row, and rises at that position, so that the four weld rows are immersed as one unit, and the thermosetting resin is melted and adhered to the weld row. The movable small powder immersion tank 31 has an immersion part necessary and sufficient for immersing the weld row, and its structure is the same as that of the large powder immersion tank 19.
[0032]
FIG. 5 is a diagram illustrating a flowchart of the second embodiment.
[0033]
STEP 61 is an initial position setting step for setting the position of the welding torch 15 at the first welded point 13. For example, it is set at the position of the welded point 13 on the innermost peripheral side of the stator 11.
[0034]
STEP 63 is a radial row welding process in which a predetermined number, for example four, of the welded points 13 arranged in a row in the radial direction are sequentially welded to form a weld row. When the welding of one welding point is completed, the welding torch 15 is moved along the radial direction of the stator 11 to the outer peripheral side by the distance between the welding points, set to the position of the next welding point 13, and welding is performed. .
[0035]
In STEP 65, when welding is completed for all the welded points 13 arranged in a predetermined number in a row in the radial direction and the weld row is formed, the work, that is, the stator 11 is rotated in the circumferential direction by a distance between the weld points. This is a circumferential movement step of moving the welding torch 13 to the position of the welding point 13 in the next row.
[0036]
In STEP67, after the welding torch 15 moves in the circumferential direction, the small powder immersion tank 31 moves to the position of the welding row, rises at that position, and immerses the welding row as a unit, and is thermosetting. This is a radial melt adhesion process in which a resin is melted and adhered.
[0037]
STEP 69 is a melt adhesion completion determination step for determining whether or not all melt adhesion has been completed. When it is determined that all the melt adhesion has not been completed, the process returns to STEP 63 to perform radial row welding.
[0038]
When STEP 71 determines in STEP 69 that all of the melt adhesion has been completed, the stator after the melt adhesion process is heated to satisfy the thermosetting condition, and the thermosetting resin that has been fused and adhered is thermoset. This is a thermosetting process for forming an insulating film.
[0039]
In this way, a predetermined number of welded points arranged in a row in the radial direction are welded to form a weld row, and the thermosetting resin is melted and adhered using the weld row as a unit. The temperature difference between them can be reduced, and the thickness of the insulating film can be made more uniform. Moreover, by using a small powder immersing tank that can be moved, there is no need for a heavy stator up-and-down mechanism for immersing in the powder immersing tank, and the equipment cost can be reduced.
[0040]
FIG. 6 is a diagram for explaining the third embodiment. In this case, after the welding torch 15 sequentially welds one welded point 13, the injection nozzle 33 sequentially injects thermosetting resin onto the welded portion. The injection nozzle 33 has a structure capable of injecting a predetermined amount of a thermosetting resin powder into a predetermined range.
[0041]
FIG. 7 is a diagram illustrating a flowchart of the third embodiment. STEP 81 is an initial position setting step for initially setting the position of the welding torch 15.
[0042]
STEP 83 is a welding process for welding one welded point 13. STEP 85 is a moving process for moving the welding torch 15 to the next welding point 13. These steps can be performed in the same manner as STEP 51, STEP 531, STEP 533, and STEP 537 of FIG. 2 in the case of the first embodiment.
[0043]
STEP 87 is an injection process in which after the welding torch 15 finishes one welding and moves to the next welding point, the injection nozzle 33 injects a thermosetting resin into the welded portion and melts and adheres the welded portion.
[0044]
STEP 89 is a complete melt adhesion completion determination step for determining whether or not the melt adhesion by welding and injection of the thermosetting resin is completed for all the weld points. When it is determined that all of them are not completed, the process returns to STEP 83 and welding is performed.
[0045]
When STEP 91 determines in STEP 89 that all the melt adhesion has been completed, the stator after the melt adhesion process is heated to satisfy the thermosetting condition, and the thermosetting resin that has been melt adhered is thermally cured. This is a thermosetting process for forming an insulating film.
[0046]
In this way, after welding one welded point, each time a thermosetting resin is sprayed, melt adhesion can be performed while there is sufficient residual heat, and the film thickness of the insulating film between the welded parts can be further increased. Can be uniform.
[0047]
As mentioned above, although the stator which uses a segment coil was picked up and demonstrated for convenience, this invention can be implemented also about the rotor where a segment coil is used.
[0048]
【The invention's effect】
The segment coil connection method according to the present invention eliminates the need for equipment for heating, and enables connection of segment coils with good work efficiency.
[Brief description of the drawings]
FIG. 1 is a diagram schematically showing a change in a preheating temperature due to welding in a room temperature atmosphere at a welding portion, which is the basis of the knowledge of the present invention.
FIG. 2 shows a flowchart of the first embodiment of the present invention.
FIG. 3 is a diagram showing a configuration in the vicinity of a welded point in a welding process.
FIG. 4 is an explanatory diagram of a second embodiment of the present invention.
FIG. 5 is a diagram showing a flowchart of a second embodiment of the present invention.
FIG. 6 is a diagram for explaining a third embodiment of the present invention.
FIG. 7 is a flowchart of a third embodiment of the present invention.
FIG. 8 is a diagram in which a cross section of a stator of a motor using a segment coil is developed in the circumferential direction.
FIGS. 9A and 9B are diagrams illustrating an example of a conventional technique regarding a connection method between segment coil ends, where FIG. 9A illustrates a welding process, FIG. 9B illustrates a heating process, and FIG. 9C illustrates a melt adhesion process. It is.
[Explanation of symbols]
1 Stator, 3 Slot, 5 Stator Winding, 7A, 7B, 7C Segment Coil, 9A, 9B, 9C, 9D End, 11 Stator, 17 Heating Furnace, 19 Powder Dipping Tank, 21 Porous Partition Plate, 23 Immersion section, 25 air inlet, 27 grounding claw for welding, 29 high voltage source, 31 small powder immersion tank, 33 spray nozzle.

Claims (5)

A segment coil in which a plurality of rows in the circumferential direction of a stator or rotor and a predetermined number of segment coils in a radial direction are welded, and an insulating film is formed by melting and adhering a thermosetting resin to the welded portion. Connection method,
A welding process in which a welding torch moves relative to the stator or the rotor and sequentially welds the welding points;
A melt adhesion step in which the thermosetting resin is adhered within a melt adhesion possible period of a predetermined temperature or higher according to the melting point of the thermosetting resin, the preheating temperature due to welding of the welded portion;
Heat-treating the attached thermosetting resin to form an insulating film; and
A method of connecting segment coils, comprising: In the connection method of the segment coil of Claim 1,
The method for connecting segment coils, wherein the predetermined temperature is 100 degrees C or more and 180 degrees C or less. In the connection method of the segment coil of Claim 1 or Claim 2,
The method for connecting segment coils, wherein the melt adhesion period is within 3 minutes from the start of welding. A segment coil in which a plurality of rows in the circumferential direction of a stator or rotor and a predetermined number of segment coils in a radial direction are welded, and an insulating film is formed by melting and adhering a thermosetting resin to the welded portion. Connection method,
A radial row welding process in which a welding torch moves in the radial direction of the stator or the rotor and welds the welded points provided in a predetermined number in the radial direction sequentially for one row;
The thermosetting resin is melt-adhered to the radial weld row portion within a possible melt adhesion period in which a preheat temperature due to welding of the weld portion is equal to or higher than a predetermined temperature corresponding to the melting point of the thermosetting resin. A radial row melt adhesion process;
Heat-treating the attached thermosetting resin to form an insulating film; and
A method of connecting segment coils, comprising: A segment coil in which a plurality of rows in the circumferential direction of a stator or rotor and a predetermined number of segment coils in a radial direction are welded, and an insulating film is formed by melting and adhering a thermosetting resin to the welded portion. Connection method,
A welding process in which a welding torch moves relative to the stator or the rotor and sequentially welds the welding points;
Injecting and melt-adhering step of sequentially injecting the thermosetting resin to the welded portion within a possible melt adhesion period in which the preheat temperature due to welding of the welded portion is equal to or higher than a predetermined temperature corresponding to the melting point of the thermosetting resin When,
Heat-treating the attached thermosetting resin to form an insulating film; and
A method of connecting segment coils, comprising:

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