Stator manufacturing method

Abstract

The invention relates to a method for manufacturing a stator. In the stator winding, a first insulating layer and a second insulating layer comprising insulating resins having different glass transition points are formed, the first insulating layer comprising a first insulating resin having a higher glass transition point, and the second insulating layer comprising a second insulating resin having a lower glass transition point. The method for manufacturing a stator comprises: a first step of applying a first insulating resin to a stator winding and hardening the first insulating resin at a temperature higher than the glass transition point thereof to form a first insulating layer; and a second step, after the first step, of applying a second insulating resin to the stator winding and hardening the second insulating resin at a temperature higher than the glass transition point thereof to form a second insulating layer.

Description

Technical Field

[0001] The invention relates to a method for manufacturing a stator. Background Art

[0002] Conventionally, in the stator of a rotating electric machine, a technique for forming an insulating layer made of an insulating resin on the surface side of a stator winding is known. Specifically, a technique for forming an insulating layer using a varnish as an insulating resin is known for the purpose of improving the fixing strength of the stator winding relative to the stator core, and a technique for forming an insulating layer using a powdered resin as an insulating resin is known for the purpose of insulating a welded portion of the stator winding.

[0003] When forming the insulating layer from the insulating resin, the insulating resin is applied to the stator winding, and the insulating resin is hardened at a predetermined high temperature. For example, in the technology described in Patent Document 1, the insulating layer is first formed on the welding part of the stator winding (specifically, the welding part where the conductor segments are connected by welding) with a powdered resin, and then the insulating layer is formed on the assembly part of the stator winding with respect to the stator core with a varnish, and when forming each insulating layer, each resin material is hardened at a high temperature.

[0004] Prior art literature

[0005] Patent Literature

[0006] Patent Document 1: Japanese Patent No. 5728981

[0007] In the stator winding, when the insulating layers are formed using a plurality of insulating resins having different glass transition points, if the insulating layer is formed using an insulating resin having a relatively low glass transition point in the previous process and the insulating layer is formed using an insulating resin having a relatively high glass transition point in the subsequent process, the insulating layer in the subsequent process is heated more than necessary for the insulating resin used in the previous process, and the insulating layer may be damaged. For example, if the glass transition point of the varnish used in the subsequent process is higher than the glass transition point of the powder resin used in the previous process, the temperature after curing becomes higher in the subsequent process due to the heating more than necessary for the powder resin. As a result, the stress becomes larger after cooling, and the insulating layer may crack or peel off. Summary of the invention

[0008] The present invention has been made in view of the above technical problems, and an object of the present invention is to provide a method for manufacturing a stator, which can appropriately form an insulating layer in a stator winding when the insulating layer is formed using a plurality of insulating resins having different glass transition points.

[0009] Hereinafter, a method for achieving the above-mentioned object and its effects will be described.

[0010] Method 1

[0011] A method for manufacturing a stator, the stator having a winding formed by winding a conductive wire material, wherein:

[0012] The winding is provided with a first insulating layer and a second insulating layer made of insulating resins having different glass transition points, wherein the first insulating layer is made of the first insulating resin having a higher glass transition point, and the second insulating layer is made of the second insulating resin having a lower glass transition point.

[0013] The manufacturing method of the stator comprises:

[0014] A first step is to apply the first insulating resin to the winding and harden the first insulating resin at a temperature higher than a glass transition point of the first insulating resin to form the first insulating layer; and

[0015] The second step is to apply the second insulating resin to the winding after the first step, and harden the second insulating resin at a temperature higher than a glass transition point of the second insulating resin to form the second insulating layer.

[0016] When manufacturing a stator, in a previous first process, a first insulating resin having a higher glass transition point is applied to a winding, and a first insulating layer is formed by curing at a temperature higher than the glass transition point of the first insulating resin. In addition, in a subsequent second process, a second insulating resin having a lower glass transition point is applied to the winding, and a second insulating layer is formed by curing at a temperature higher than the glass transition point of the second insulating resin. In this case, when curing the second insulating resin in the subsequent process (second process), it is not necessary to use a temperature that is too high compared to the curing of the first insulating resin in the previous process (first process), and undesirable conditions such as breakage of the first insulating layer can be suppressed. As a result, when forming an insulating layer in a stator winding using a plurality of insulating resins having different glass transition points, the insulating layer can be formed appropriately.

[0017] In method 2, in the first step, the winding is heated, and in the second step, after the winding is heated and the first insulating resin is applied in the first step, the second insulating resin is applied to the winding while the temperature of the winding is maintained at a high temperature higher than the glass transition point of the second insulating resin and at a temperature at which the second insulating resin can be cured.

[0018] After the heating of the winding and the coating of the first insulating resin, the temperature of the winding gradually decreases. However, when the glass transition point of the first insulating resin is a higher temperature than the glass transition point of the second insulating resin, it can be considered that the temperature of the winding during or after the curing of the first insulating resin is higher than the curing temperature required for the curing of the second insulating resin. Therefore, even if the winding is not reheated when the second insulating resin is coated, the second insulating layer can be formed by the second insulating resin. In this case, the reheating of the winding in the second process is not required, and the time required for forming the insulating layer can be shortened, and the cost can be reduced.

[0019] In the third aspect, after the first insulating resin is applied in the first step, a heat-insulating member is used to suppress a temperature drop of the winding.

[0020] In the previous step, when the first insulating resin having a relatively high glass transition point is heated and hardened, the winding is kept warm by the heat-insulating member. In this case, the temperature of the winding decreases slowly after the heating of the winding is stopped. Therefore, the heating temperature of the winding in the first step can be reduced, and the time required for the hardening of the first insulating resin can be shortened.

[0021] Furthermore, in a later step, when the second insulating resin is applied and cured without reheating the winding, it is possible to suppress the inconvenience of the winding temperature unintentionally dropping to a temperature lower than the desired temperature and failing to properly cure the second insulating resin.

[0022] In aspect 4, in the first step, the first insulating resin is applied to the winding during a heating period of heating the winding.

[0023] In the previous process, the first insulating resin is applied to the winding while the winding is heated. This can suppress the temperature drop of the winding when applying the first insulating resin, and further shorten the curing time of the first insulating resin. By shortening the curing time of the first insulating resin, it is possible to suppress the undesirable situation that the first insulating resin flows to an undesirable area, and it is possible to suppress the influence on the application of the second insulating resin in the subsequent process. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 It is an axial cross-sectional view of the rotating electrical machine according to the embodiment.

[0025] Figure 2 It is a perspective view showing the entire stator.

[0026] Figure 3 This is an explanatory diagram showing a state where a conductor segment is inserted into a stator core.

[0027] Figure 4 This is the front view of the stator.

[0028] Figure 5 This is a flowchart showing the structural process related to the formation of the covering portion of the stator winding.

[0029] Figure 6 It is a timing chart showing the transition of the winding temperature when the coating portion is formed.

[0030] Figure 7 It is a diagram for explaining the process of forming the first covering portion.

[0031] Figure 8 It is a diagram for explaining the process of forming the second covering portion.

[0032] Fig. 9 This is a diagram showing a state where the stator is kept warm by a heat-insulating member.

[0033] Fig.10 It is a timing chart showing the transition of the winding temperature when the coating portion is formed.

[0034] Fig.11 It is a timing chart showing the transition of the winding temperature when the coating portion is formed.

[0035] Fig.12 It is a timing chart showing the transition of the winding temperature when the coating portion is formed.

[0036] Fig.13 It is a timing chart showing the transition of the winding temperature when the coating portion is formed. DETAILED DESCRIPTION

[0037] Hereinafter, an embodiment of the rotating electric machine according to the present invention will be described based on the accompanying drawings. The electric machine of the rotating electric machine according to this embodiment is used as an electric motor for a vehicle or an electric motor for an aircraft, for example. The rotating electric machine according to this embodiment is headed by a permanent magnet synchronous motor, can be applied to a winding excitation type or an induction machine, and is a rotating electric machine having a three-phase winding. In addition, in the following embodiments and modifications, the same or equivalent parts are marked with the same symbols in the drawings, and the description of the parts with the same symbols is cited.

[0038] like Figure 1 As shown in the figure, the rotating electric machine 10 includes: a rotor 12 fixed to a rotating shaft 11, a stator 13 provided at a position surrounding the rotor 12, and a housing 14 accommodating the rotor 12 and the stator 13. The rotating electric machine 10 is an inner rotor type rotating electric machine, and the rotor 12 is rotatably arranged radially inside the stator 13. In this embodiment, the axial direction indicates the axial direction of the rotating shaft 11, the radial direction indicates the direction orthogonal to the rotating shaft 11, and the circumferential direction indicates the rotation direction centered on the rotating shaft 11.

[0039] The housing 14 has a pair of bottomed cylindrical housing parts 14a and 14b, and the housing parts 14a and 14b are integrated by fastening with bolts 15 in a state where the openings are joined to each other. Bearings 16 and 17 are provided in the housing 14, and the rotating shaft 11 and the rotor 12 are supported rotatably by the bearings 16 and 17. The rotor 12 has a plurality of magnetic poles arranged at a predetermined distance in the circumferential direction and with different polarities in alternation on the outer peripheral side of the rotor 12 which is radially opposite to the inner peripheral side of the stator 13. These magnetic poles are formed by a plurality of permanent magnets buried in predetermined positions of the rotor 12.

[0040] Next, the stator 13 will be described. Figure 2 and Figure 3 As shown, the stator 13 includes a circular stator core 20 and a stator winding 30, wherein the stator core 20 has a plurality of slots 21 in the circumferential direction, and the stator winding 30 is wound around each slot 21 of the stator core 20. The stator winding 30 includes a U-phase winding, a V-phase winding, and a W-phase winding as phase windings of each phase. In the stator winding 30, the range that overlaps with the stator core 20 in the axial direction is the coil side CS. In addition, at one end side and the other end side in the axial direction, the portions that are axially outside compared to the stator core 20 are the first coil end CE1 and the second coil end CE2.

[0041] The stator core 20 has an annular back yoke 23 and a plurality of teeth 24 protruding radially inward from the back yoke 23 and arranged at a predetermined distance in the circumferential direction, and a slot 21 is formed between adjacent teeth 24. The slots 21 are in an open shape extending with the radial direction as the long side, and are arranged at equal intervals in the circumferential direction in the stator core 20. In addition, a stator winding 30 is arranged in a manner wound around the slots 21. The stator core 20 is configured as a core sheet laminate, which is formed by laminating core sheets formed of, for example, electromagnetic steel sheets as magnetic bodies in the axial direction.

[0042] The stator winding 30 is composed of three-phase windings connected by Y-connecting lines (star-connecting lines). The stator winding 30 generates magnetic flux by supplying power (AC power) from a power source via an inverter not shown. The stator winding 30 is composed of a plurality of conductor segments 40, which are divided conductors formed into a roughly U-shaped electric conductor with a constant thickness and a roughly rectangular cross-section (flat cross-section). The conductor segment 40 is equivalent to a "conducting wire material". The segmented structure of the stator winding 30 is described in detail below.

[0043] like Figure 3As shown, the conductor segment 40 is substantially U-shaped and has a pair of straight portions 41 in a straight line shape and a turn portion 42 formed by bending the pair of straight portions 41 to connect each other. The pair of straight portions 41 has a length longer than the axial thickness of the stator core 20. The conductor segment 40 is formed using a flat wire in which a conductor 51 having a rectangular cross section is covered with an insulating film 52, and a terminal portion 43 as the top end portion of each straight portion 41 is formed by cutting off the insulating film 52 to form a conductor exposed portion in which the conductor 51 is exposed.

[0044] A plurality of conductor segments 40 are inserted into the slots 21 of the stator core 20 in a state of being arranged in a row in the radial direction. In the present embodiment, the slots 21 are configured to accommodate the straight portions 41 of the conductor segments 40 in a stacked state of eight layers. In the conductor segment 40, a pair of straight portions 41 are respectively accommodated in two slots 21 separated by a predetermined coil pitch. The portion of the straight portion 41 accommodated in the slot 21 corresponds to the coil side CS. An insulating sheet 26 for electrically insulating the stator core 20 from the stator winding 30 (conductor segment 40) is provided in the slot 21. The insulating sheet 26 is bent in a manner to centrally surround the plurality of conductor segments 40 inserted in the slots 21, and is provided in the slot 21 in a state of being sandwiched between the inner circumferential surface (inner wall surface) of the stator core 20 and the conductor segment 40.

[0045] A pair of straight portions 41 of the conductor segment 40 are respectively accommodated in the two slots 21 at a radially offset position. For example, when one straight portion 41 is accommodated at the nth position from the radial inner side (back yoke side), the other straight portion 41 is accommodated at the n+1th position from the radial inner side.

[0046] When each conductor segment 40 is inserted into the slot 21 of the stator core 20, the straight portion 41 of each conductor segment 40 is inserted from the first end side of the first end side and the second end side of the axial ends of the stator core 20, and the terminal portion 43 of the straight portion 41 protrudes from the second end side. In this case, at the first end side of the stator core 20, the first coil end CE1 is formed by the turn portion 42 of the conductor segment 40. In addition, at the second end side of the stator core 20, the anti-turn portion side of each straight portion 41 is bent in the circumferential direction, and the terminal portions 43 of different conductor segments 40 are joined to each other by welding or the like, thereby forming the second coil end CE2.

[0047] In the stator 13, the stator winding 30 is insulated and coated. The structure thereof is described below. Specifically, in the stator winding 30, each coil end CE1, CE2 and the coil side CS are insulated and coated. Figure 4 The outline thereof is shown in FIG. Figure 4 It is a front view of the stator 13.

[0048] exist Figure 4In the embodiment, the side of the turning portion 42 of the conductor segment 40 on both axial sides of the stator core 20 is the first coil end CE1, the side of the terminal portion 43 of the conductor segment 40 is the second coil end CE2, and the range overlapping with the stator core 20 in the axial direction is the coil side CS. In the stator winding 30, a first covering portion 61 is formed in a portion other than the welded portion of the terminal portion 43 in each conductor segment 40, and a second covering portion 62 is formed in a portion corresponding to the welded portion of the terminal portion 43. In other words, the first covering portion 61 is formed to cover the entire area of ​​the first coil end CE1 and the coil side CS and the portion of the second coil end CE2 other than the welded portion of the terminal portion 43. In addition, the first covering portion 61 may also be formed in a range that at least includes the first coil end CE1 and the coil side CS. In addition, the second covering portion 62 is formed to cover the welded portion of the terminal portion 43 in the second coil end CE2.

[0049] The first covering portion 61 is formed, for example, to fix the stator winding 30 to the stator core 20 to improve the mechanical strength, or to impart water resistance and corrosion resistance to the stator winding 30. The first resin material (first insulating resin) used for the first covering portion 61 is a resin material generally called varnish. As the first resin material, for example, any synthetic resin such as epoxy, phenol, polyester, silicone, etc. can be used.

[0050] The second covering portion 61 is formed to protect the welded portion at the terminal portion 43 of the conductor segment 40 and to provide insulation to the conductor exposed portion of the terminal portion 43. The second resin material (second insulating resin) used for the second covering portion 62 is, for example, a powdered resin, specifically, a material having an epoxy or polyester resin component as a main component.

[0051] The first covering portion 61 and the second covering portion 62 are formed as insulating covering layers composed of resin materials with different glass transition points. In the present embodiment, the first resin material used for the first covering portion 61 is a resin material with a relatively high glass transition point, and the second resin material used for the second covering portion 62 is a resin material with a relatively low glass transition point. That is, the glass transition point Tg1 of the first resin material and the glass transition point Tg2 of the second resin material are in the relationship of Tg1>Tg2. For example, the glass transition point Tg1 of the varnish as the first resin material is 170°C, and the glass transition point Tg2 of the powdered resin as the second resin material is 130°C. The first covering portion 61 is equivalent to the "first insulating layer", and the second covering portion 62 is equivalent to the "second insulating layer".

[0052] Next, the manufacturing steps of the stator 13 will be described. Figure 5 1 is a flowchart showing a manufacturing process related to the formation of each covering portion 61, 62 of the stator winding 30 in the manufacturing method of the stator 13. Figure 6It is a timing chart showing the change of the temperature of the stator winding 30 when forming the coating portions 61 and 62. Here, the steps after the assembly of the conductor segments 40 to the stator core 20 in the stator 13 and the welding of the terminal portions 43 of the conductor segments 40 are completed are described.

[0053] exist Figure 5 In the embodiment, the first covering portion 61 is first formed on the stator winding 30 using the first resin material, and then the second covering portion 62 is formed using the second resin material. Figure 5 In the embodiment, steps S1 to S3 are steps of forming the first covering portion 61 on the stator winding 30, and steps S4 to S5 are steps of forming the second covering portion 62 on the stator winding 30. Steps S1 to S3 correspond to the "first step", and steps S4 to S5 correspond to the "second step".

[0054] In the step of forming the first covering portion 61 (S1 to S3), the stator is mounted on Figure 7 The jig 71 shown in the figure is used to form the first covering portion 61 by using the first resin material supplied from the glue coating machine 72. The first resin material is, for example, varnish. Figure 7 In the figure, the stator 13 is mounted on the jig 71 with the first coil end CE1 side at the top and the second coil end CE2 side at the bottom, and with the central axis tilted with respect to the vertical direction.

[0055] In step S1, the stator winding 30 is heated to a predetermined temperature higher than the glass transition point Tg1 of the first resin material (heating step). At this time, the stator winding 30 is heated to a predetermined temperature by energizing the stator winding 30 under predetermined energizing conditions. As energizing conditions, the magnitude of the energizing current and the energizing time can be predetermined. In addition, the temperature of the stator winding 30 can be detected by a temperature sensor, etc., and energized heating can be performed until the detected temperature reaches a predetermined target temperature.

[0056] In step S2, a liquid first resin material is applied to the first coil end CE1 of the stator winding 30 from a glue coating machine 72 (a first coating step). At this time, a predetermined amount of the first resin material is dripped from the glue coating machine 72 every hour while the stator 13 rotates together with the clamp 71 while the clamp 71 rotates around the rotating shaft 73. Thus, the first resin material is applied to the first coil end CE1 in the circumferential direction. When the first resin material is applied to the first coil end CE1 of the stator winding 30, the first resin material flows into the narrow slot 21 (coil side CS) along the conductor segment 40, and then flows out to the second coil end CE2 on the opposite side. That is, in the stator winding 30, a thin layer of the first resin material is formed in the range from the first coil end CE1 to the second coil end CE2 in the axial direction. In addition, the first resin material can be applied to at least the range from the first coil end CE1 to the coil side CS. At this time, the stator 13 may be oriented horizontally with the second coil end CE2 at the lower side, and in this state, the first resin material may be fed from the first coil end CE1 side to the second coil end CE2 side.

[0057] Then, in step S3, the first resin material is cured when the stator winding 30 reaches a predetermined curing temperature (first curing step). That is, when the surface of the stator winding 30 is covered with the first resin material, the first resin material solidifies to form the first covering portion 61. Specifically, when the temperature of the stator winding 30 gradually decreases after the application of the first resin material, the first covering portion 61 is formed by curing the first resin material.

[0058] exist Figure 6 In the timing diagram of , during the period T1, the stator winding 30 is heated to a predetermined temperature Th higher than the glass transition point Tg1 of the first resin material. Next, during the period T2, the first resin material is applied to the first coil end CE1 of the stator winding 30, and then, during the period T3, the first resin material is cured in a high temperature environment having a predetermined curing temperature higher than the glass transition point Tg1 of the first resin material. Thus, the first covering portion 61 is formed.

[0059] exist Figure 5 In the process of forming the second covering portion 62 using the second resin material after forming the first covering portion 61, the forming process of the second covering portion 62 is continued. In the forming process (S4 to S5) of the second covering portion 62, the second covering portion 62 is formed using the second resin material having a lower glass transition point than the glass transition point of the first resin material, and the second resin material is hardened using the heat of the stator winding 30 remaining after the forming process of the first covering portion 61. That is, in the present embodiment, the stator winding 30 is not reheated in the forming process of the second covering portion 62.

[0060] In step S4, a second resin material is applied to the axial top end (welding portion) of the second coil end CE2 of the stator winding 30 (second application step). The second resin material is, for example, a powdered resin. Specifically, Figure 8 As shown, the second resin material in liquid form is pre-filled in the dipping tank 74, and the second resin material is attached to the surface of the welded portion by dipping the welded portion of the second coil end CE2 in the dipping tank 74. In step S4, after the first covering portion 61 is formed using the first resin material having a relatively high glass transition point, the second resin material is applied to the stator winding 30 before the winding temperature reaches a low temperature lower than the glass transition point of the second resin material having a relatively low glass transition point.

[0061] Then, in step S5, the second coil end CE2 is lifted from the immersion tank 74, and the second resin material is cured in a temperature region higher than the glass transition point Tg2 of the second resin material (second curing step). Thus, the second covering portion 62 is formed by the second resin material at the welded portion of the second coil end CE2.

[0062] exist Figure 6 In the timing diagram of FIG. 1 , in the period T4, the second resin material is applied to the welded portion of the second coil end CE2 while the stator winding 30 is at a predetermined temperature higher than the glass transition point Tg2 of the second resin material by the residual heat after the formation process (S1 to S3) of the first covering portion 61. Thereafter, in the period T5, the second covering portion 62 is formed by curing the second resin material. The application of the second resin material may be performed either during the curing of the first resin material or after the curing is completed.

[0063] Here, assuming that the second covering portion 62 is first formed using the second resin material with a low Tg, and then the first covering portion 61 is formed using the first resin material with a high Tg, the second covering portion 62 (second resin material) is excessively reheated when the first covering portion 61 is formed. Therefore, the stress in the second covering portion 62 increases after cooling, and cracks and other defects may occur. In this regard, in the present embodiment, the first covering portion 61 is first formed using the first resin material with a high Tg, and then the second covering portion 62 is formed using the second resin material with a low Tg, so that the second covering portion 62 (second resin material) is not excessively heated, and the stress after cooling is reduced.

[0064] In the formation process (S1 to S3) of the first covering portion 61, the temperature rise temperature Th when the winding is heated can be determined based on the glass transition point Tg1 of the first resin material (varnish), the temperature drop rate of the winding temperature in the heated environment (temperature drop amount per unit time), and the curing time required to cure the first resin material at a curing temperature higher than the glass transition point Tg1. In addition, the temperature drop rate (temperature drop environment) of the winding temperature after heating can also be determined based on the temperature rise temperature Th when the winding is heated and the curing time of the first resin material.

[0065] In addition, in the step (S4-S5) of forming the second covering portion 62, the timing of applying the second resin material can be determined based on the glass transition point Tg2 of the second resin material (powdered resin), the temperature drop rate of the winding temperature, and the curing time required to cure the second resin material at a curing temperature higher than the glass transition point Tg2. Thus, the processing conditions for forming each covering portion 61, 62 can be appropriately determined.

[0066] In the step (S1 to S3) of forming the first covering portion 61, a heat-insulating member may be used to suppress a decrease in the temperature of the stator winding 30. Specifically, Fig. 9 As shown in FIG. 1 , a heat-insulating cover 75 as a heat-insulating member may cover the stator 13. In this case, as shown in FIG. Fig.10 As shown in FIG. 1 , after the stator winding 30 is heated in step S1 , the decrease in the winding temperature is suppressed. Fig.10 , the change in winding temperature when the heat-insulating cover 75 is not used is indicated by a single-dot chain line. When the heat-insulating cover 75 is not used, the stator winding 30 is heated to the heating temperature Th, whereas when the heat-insulating cover 75 is used, the stator winding 30 is heated to the heating temperature Tha.

[0067] exist Fig.10 In the period T1, after the stator winding 30 is heated to the heating temperature Tha, the winding temperature is reduced relatively slowly. Therefore, the heating temperature of the stator winding 30 can be reduced. Fig.10 In the embodiment, the heating temperature is set to Tha which is lower than Th, considering that the winding temperature decreases slowly. However, when the heating temperature is still set to Th, the winding temperature is maintained at a higher temperature, thereby shortening the time required to cure the first resin material.

[0068] The heat-insulating member may be a structure other than the heat-insulating cover 75 , and a heat-insulating box that accommodates the stator 13 may be used as the heat-insulating member.

[0069] In addition, if Fig.11As shown, during the period T2 (first coating process) of applying the first resin material to the stator winding 30, the heating of the stator winding 30 may also be continued. That is, the heating period of the stator winding 30 and the coating period of the first resin material may overlap partially. Thus, the temperature drop of the stator winding 30 during the coating of the first resin material is suppressed, and the curing time of the first resin material can be shortened.

[0070] According to the present embodiment described in detail above, the following excellent effects can be obtained.

[0071] When manufacturing the stator 13, in the previous process (S1 to S3), a first resin material having a higher glass transition point is applied to the stator winding 30, and the first covering portion 61 is formed by curing at a temperature higher than the glass transition point Tg1 of the first resin material. In addition, in the subsequent process (S4 to S5), a second resin material having a lower glass transition point is applied to the stator winding 30, and the second covering portion 62 is formed by curing at a temperature higher than the glass transition point Tg2 of the second resin material. In this case, when the second resin material is cured in the subsequent process, it is not necessary to set the temperature to be excessively higher than that when the first resin material is cured in the previous process, and it is possible to suppress the damage of the first covering portion 61 and other unfavorable conditions. As a result, when the insulating layer (covering portions 61, 62) is formed in the stator winding 30 using a plurality of resin materials having different glass transition points, the insulating layer can be appropriately formed.

[0072] After the stator winding 30 is heated and the first resin material is applied, the temperature of the stator winding 30 gradually decreases, but when the glass transition point Tg1 of the first resin material is a higher temperature than the glass transition point Tg2 of the second resin material, it can be considered that the winding temperature during or after the curing of the first resin material is higher than the curing temperature required for the curing of the second resin material. Therefore, even if the stator winding 30 is not reheated when the second resin material is applied, the second covering portion 62 can be formed by the second resin material. In view of this, the second resin material is applied to the stator winding 30 while the winding temperature is being reduced after the first resin material is applied, while the winding temperature is maintained at a higher temperature than the glass transition point Tg2 of the second resin material and at a temperature at which the second resin material can be cured (see Figure 6 In this case, reheating of the stator winding 30 in a later process is not necessary, and the time required for forming the insulating layer can be shortened, thereby reducing costs.

[0073] In the previous steps (S1 to S3), when the first resin material having a relatively high glass transition point is heated and hardened, the stator winding 30 is kept warm by the heat-insulating cover 75 (see Fig. 9 , Fig.10). In this case, the temperature of the stator winding 30 decreases slowly after the heating is stopped. Therefore, the heating temperature of the stator winding 30 in the first step can be reduced, and the time required for the curing of the first resin material can be shortened.

[0074] In addition, in the subsequent process (S4~S5), when the second resin material is applied and cured without reheating the stator winding 30, it is possible to prevent the winding temperature from undesirably decreasing to a temperature lower than the desired temperature and failing to properly cure the second resin material.

[0075] In the previous steps (S1 to S3), the first resin material (see Fig.11 ). Thus, the temperature drop of the stator winding 30 during the application of the first resin material can be suppressed, and the curing time of the first resin material can be shortened. By shortening the curing time of the first resin material, the undesirable situation that the first resin material flows to an undesirable area can be suppressed, and the influence on the application of the second resin material in the subsequent process can be suppressed.

[0076] (Other embodiments)

[0077] For example, the above-mentioned embodiment may be modified as follows.

[0078] like Fig.12 As shown, in the front process (S1 to S3), the heat preservation cover 75 is used to suppress the decrease in the winding temperature, and in the back process (S4 to S5), the heat preservation cover 75 may not be used and the decrease in the winding temperature may not be suppressed. In this case, the slope of the decrease in the winding temperature when the resin in the front process is hardened is different from that when the resin in the back process is hardened, and the slope of the decrease in the winding temperature in the latter is larger. Therefore, in the front process, the heat demand for the hardening of the second resin material in the back process is predicted to suppress the heat release of the stator winding 30, and in the back process, after the hardening of the second resin material, the winding temperature can be quickly reduced to room temperature. Thereby, the time required for the formation of the covering portion can be shortened.

[0079] like Fig.13 As shown, the stator winding 30 may be heated in each of the steps of forming the first covering portion 61 and forming the second covering portion 62 .

[0080] exist Fig.13In the process, during the period T11, the stator winding 30 is heated to a predetermined temperature Th1 higher than the glass transition point Tg1 of the first resin material (varnish). Next, during the period T12, the first resin material is applied, and during the period T13, the first resin material is cured in a temperature environment higher than the glass transition point Tg1 of the first resin material. Thus, the first covering portion 61 is formed.

[0081] Then, during the period T14, the stator winding 30 is heated to a predetermined temperature Th2 higher than the glass transition point Tg2 of the second resin material (powdered resin) by reheating the stator winding 30. Next, during the period T15, the second resin material is applied, and during the period T16, the second resin material is cured in a temperature environment higher than the glass transition point Tg2 of the second resin material. Thus, the second covering portion 62 is formed.

[0082] In addition, in the formation process of the second covering portion 62 (period T4 to T6), the heating temperature Th2 during winding heating can also be determined based on the glass transition point Tg2 of the second resin material, the temperature drop rate of the winding temperature in the reheated environment (temperature drop per unit time), and the curing time required for the curing of the second resin material at a curing temperature higher than the glass transition point Tg2.

[0083] In the above embodiment, the stator winding 30 is heated by energizing, but this may be modified. For example, the stator winding 30 may be heated in a heating device (hot air furnace) or by electromagnetic heating.

[0084] In the above-mentioned embodiment, a varnish having a relatively high glass transition point and a powdered resin having a relatively low glass transition point are used, and the varnish is used as the first resin material (first insulating resin) and the powdered resin is used as the second resin material (second insulating resin). However, this may be changed. In the case of using a powdered resin having a relatively high glass transition point and a varnish having a relatively low glass transition point, the powdered resin may be used as the first resin material (first insulating resin) and the varnish may be used as the second resin material (second insulating resin). In this case, in the previous process, the first insulating layer (for example, a layer equivalent to the first insulating resin) may be formed using the powdered resin as the first insulating resin. Figure 4 In a later step, a second insulating layer (e.g., equivalent to Figure 4 The first covering portion 61).

[0085] The combination of two insulating resins is not limited to varnish and powdered resin. For example, two varnishes having different glass transition points or two powdered resins having different glass transition points may be used as the two insulating resins.

[0086] The stator 13 may be configured to have an insulating layer formed of three types of insulating resins. In this case, at least two of the three insulating resins may have glass transition points different from each other. In this case, after forming the insulating layer using an insulating resin having a higher glass transition point, another insulating resin having a lower glass transition point may be used, as described above.

[0087] In the above-described embodiment, the stator 13 uses the stator winding 30 of the segment structure, but the present invention is not limited thereto and a stator winding other than the segment structure may be used.

[0088] Alternatively, by maintaining Figure 5 The stator winding 30 in step S3 shown in the figure is energized to maintain the temperature of the stator winding 30 in step S3 at a constant temperature higher than the glass transition point of the first resin material, so that the first resin material is hardened at a constant temperature higher than the glass transition point of the resin material. Figure 5 In the step S5 shown, the temperature of the stator winding 30 is maintained at a constant temperature higher than the glass transition point of the second resin material, so that the second resin material is hardened at a constant temperature higher than the glass transition point of the resin material.

Claims

1. A method for manufacturing a stator, the stator having a winding formed by winding a conductive wire material, characterized in that: The winding is provided with a first insulating layer and a second insulating layer made of insulating resins having different glass transition points, wherein the first insulating layer is made of the first insulating resin having a higher glass transition point, and the second insulating layer is made of the second insulating resin having a lower glass transition point. The manufacturing method of the stator comprises: In a first step, the first insulating resin is applied to the winding, and the first insulating resin is hardened at a temperature higher than a glass transition point of the first insulating resin to form the first insulating layer; as well as The second step is to apply the second insulating resin to the winding after the first step, and harden the second insulating resin at a temperature higher than a glass transition point of the second insulating resin to form the second insulating layer.

2. The method for manufacturing a stator according to claim 1, characterized in that: In the first step, the winding is heated. In the second process, after the heating of the winding and the application of the first insulating resin in the first process, the second insulating resin is applied to the winding while the temperature of the winding is maintained at a high temperature higher than the glass transition point of the second insulating resin and at a temperature at which the second insulating resin can be cured.

3. The method for manufacturing a stator according to claim 1 or 2, characterized in that: After the first insulating resin is applied in the first step, a temperature drop of the winding is suppressed by a heat insulating member.

4. The method for manufacturing a stator according to claim 1 or 2, characterized in that: In the first step, the first insulating resin is applied to the winding while the winding is heated.

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