Manufacturing method for rotary electric machine

Abstract

To provide a manufacturing method for a rotary electric machine capable of preventing insufficient filling of varnish and reducing the energy required to complete filling of varnish.SOLUTION: A manufacturing method for a rotary electric machine includes: an electric component assembling process S1; a pole inserting process S2 for inserting a slot pole between a pair of coils of a rotor; a first heating process S3 for heating the rotor in a low-temperature first heating furnace; a first varnish dripping process S4 for dripping varnish onto the coil of the rotor; a first varnish hardening step S5 for hardening the varnish by putting the rotor into the first heating furnace again; a sheet foaming process S6 for foaming a foamed insulating sheet by putting the rotor into a high-temperature second heating furnace; a second varnish dripping step S7 for dripping the varnish at a position of arranging the slot pole of the rotor; and a second varnish hardening step S8 for hardening the varnish by putting the rotor into the second heating furnace again.SELECTED DRAWING: Figure 4

Description

[Technical field]

[0001] The present invention relates to a method for manufacturing a rotating electric machine. [Background technology]

[0002] In recent years, efforts to realize a low-carbon or carbon-free society have become more active, and research and development into electrification technologies is being conducted in vehicles to reduce CO2 emissions and improve energy efficiency. For example, in rotating electrical machines such as vehicle drive motors, wound field motors are sometimes used instead of the mainstream embedded magnet type. Wound field motors place a coil on the rotor instead of a permanent magnet, and generate magnetic flux in the rotor by passing a current through this coil. Wound field motors are expected to operate highly efficiently by making it possible to adjust the amount of magnetic flux in the rotor, and by not using permanent magnets, there are no concerns about the stable supply of rare earths.

[0003] That is, at least one of the stator and rotor of the motor has a circular annular portion, a plurality of cores (teeth) protruding radially inward or outward from the annular portion, and a coil with a conducting wire wound around the outer periphery of each core. For example, Patent Document 1 discloses a manufacturing method for a stator (electrical component) in which the stator body is preheated, and then varnish is dripped onto the coil. The varnish, which comes into contact with the coil and is heated to reduce its viscosity, is then allowed to penetrate the coil, making it possible to apply the varnish to the entire coil with a small amount of dripping. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Patent No. 4593291 Summary of the Invention [Problem to be solved by the invention]

[0005] Meanwhile, between adjacent coils in the circumferential direction of the motor, a plate-like member (slot pole) is arranged to insulate the coils and fix the coil positions. Between the slot pole and the coil, there are gaps of various sizes due to the unevenness of the outermost layer of the winding. Therefore, even if varnish is applied to the position where the slot pole is arranged, some of the varnish may not remain in the gap but may flow down, resulting in insufficient varnish application.

[0006] In response to this problem, it has been considered to insert a foamed insulating sheet together with a slotted pole between the coils, and then foam the foamed insulating sheet to fill the gaps before filling them with varnish. However, the foaming temperature of the foam insulation sheet is higher than the hardening temperature of the varnish, and after foaming the foam insulation sheet, the workpiece must be cooled and then heated again to a temperature suitable for the varnish to penetrate, thereby filling the workpiece with varnish. This increases the energy required to complete the filling of the varnish, and an improvement is needed.

[0007] Therefore, an object of the present invention is to provide a method for manufacturing a rotating electric machine that can prevent insufficient filling of varnish and reduce the energy required to complete filling of varnish, thereby contributing to improving energy efficiency. [Means for solving the problem]

[0008] As a means for solving the above-mentioned problems, a first aspect of the present invention is a manufacturing method for a rotating electric machine in which a winding is wound around each of a plurality of teeth aligned in a motor circumferential direction to form a plurality of coils, and a plate-shaped slot pole that provides insulation between a pair of coils adjacent to each other in the motor circumferential direction is disposed between the pair of coils, the method including an electric component assembly process for obtaining an annular electric component in which a coil is formed on each of a plurality of teeth aligned in the motor circumferential direction; a pole insertion process for inserting a slot pole with a foamed insulation sheet affixed only to one end on one side in the motor axial direction between a pair of coils adjacent to each other in the motor circumferential direction in the electric component; and a third heating process for heating the electric component with the slot pole inserted in a first heating furnace that is lower in temperature than the temperature at which the foamed insulation sheet foams. The method includes a first heating step, a first varnish dripping step of dripping varnish onto each coil from the other axial side of the electric component after the first heating step, a first varnish hardening step of placing the electric component after the first varnish dripping step back into the first heating furnace and hardening the varnish dripped in the first varnish dripping step, a sheet foaming step of placing the electric component after the first varnish hardening step in a second heating furnace which is hotter than the first heating furnace and foaming a foamed insulation sheet, a second varnish dripping step of dripping varnish onto each arrangement position of the slot pole from the other axial side of the electric component after the sheet foaming step, and a second varnish hardening step of placing the electric component after the second varnish dripping step back into the second heating furnace and hardening the varnish dripped in the second varnish dripping step.

[0009] According to this configuration, in an electric component having a plurality of teeth and coils arranged in the motor circumferential direction, a slot pole with a foamed insulating sheet attached only to one end of the motor axial direction is inserted between a pair of coils adjacent in the motor circumferential direction. After the electric component assembly process, the electric component is preheated in a first heating furnace at a relatively low temperature, and then varnish is dripped onto each coil to allow it to penetrate, and then the electric component is placed again in the first heating furnace to harden the varnish. By applying varnish only to each coil in this way, the amount of varnish used can be reduced compared to a configuration in which the electric component is immersed in a dip tank and varnish is applied. In addition, by reducing the application of varnish around the coils, it becomes easier to push out or pull out the coils when disassembling the electric component. In addition, by continuously using the first heating furnace at a relatively low temperature in the early stages of the manufacturing process of the electric component, the energy required from preheating the electric component to hardening the varnish can be reduced. After the varnish dripped onto the coil has hardened, the electric components are placed in a second heating furnace, which is hotter than the first heating furnace, to foam the foamed insulation sheet. This closes the gap between the coil and the slot pole around the end of the slot pole on one side in the motor axial direction. Then, by dripping varnish onto the location of the slot pole from the other side in the motor axial direction, the dripped varnish can be prevented from leaking out of the one side in the motor axial direction and the varnish can be filled around the slot pole. The varnish filled around the slot pole is hardened by placing the electric components again in the second heating furnace. At this time, the varnish can be hardened by utilizing the residual heat of the second heating furnace. In this way, by setting the process of filling the rotating electric machine with varnish in order of increasing temperature up to the sheet foaming process, and then in order of decreasing temperature after the sheet foaming process, it is possible to prevent insufficient filling of varnish while reducing the energy required to complete filling of the varnish. Effect of the Invention

[0010] According to the present invention, it is possible to provide a method for manufacturing a rotating electric machine that can prevent insufficient filling of varnish and reduce the energy required until filling of varnish is completed. [Brief description of the drawings]

[0011] [Figure 1] 1 is an exploded perspective view of a motor according to an embodiment of the present invention. [Diagram 2] 4 is a plan view showing a part of a circumferential direction of a rotor of the motor as viewed from an axial direction, including a partial cross section. FIG. [Diagram 3] FIG. 2 is a perspective view including a cross section along the axial direction of the rotor. [Figure 4] FIG. 4 is a flow chart showing a manufacturing process of the rotor. [Diagram 5] 5A and 5B are explanatory diagrams showing the temperature history of a heating furnace in the manufacturing process of the rotor, where (a) shows the temperature history of the embodiment and (b) shows the temperature history of a comparative example. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0012] Hereinafter, an embodiment of the present invention will be described with reference to the drawings. <Motor 1> FIG. 1 is an exploded perspective view of a motor (rotating electric machine) 1 to which an embodiment of the present invention is applied. 1, the motor 1 includes a rotor 2, a stator 3, and a casing (not shown) that covers the rotor 2 and the stator 3. In this embodiment, the rotor 2 is disposed on the inner peripheral side of the stator 3. In other words, the motor 1 is an inner rotor type motor.

[0013] The motor 1 of the embodiment is a drive motor for an electric vehicle. The motor 1 of the embodiment is a wound field motor, and has a rotor structure using a field winding (coil 37) instead of a permanent magnet. The motor 1 generates a magnetic flux in the rotor 2 by passing a direct current from an external source through the field winding, and makes the field magnetic flux adjustable.

[0014] <Rotor 2> The rotor 2 has a rotating shaft 21, a rotor core 22, a plurality of magnetic pole portions 23, and a commutator 24. The rotating shaft 21 extends in an axial direction (motor axial direction) Da. The rotating shaft 21 is supported by a casing via bearings (both not shown). The rotating shaft 21 is supported rotatably in a circumferential direction (motor circumferential direction) Dc about an axis C extending in the axial direction Da.

[0015] The rotor core 22 is provided outside (on the outer periphery side) of the rotating shaft 21 in a radial direction (motor radial direction) Dr centered on the axis C. The rotor core 22 is formed in a cylindrical shape with the axis C as its axis. When viewed from the axial direction Da, a shaft insertion hole 22a through which the rotating shaft 21 is inserted is formed in the center of the rotor core 22. The rotor core 22 is rotatable integrally with the rotating shaft 21 in the circumferential direction Dc.

[0016] The magnetic pole portions 23 are disposed at equal intervals in the circumferential direction Dc on the outer periphery of the rotor core 22. Each magnetic pole portion 23 includes a coil 37. The coil 37 is formed by winding the winding 32 via an insulator 38 around the outer periphery of a tooth 35 formed on the rotor core 22. The coil 37 and the insulator 38 will be described in detail later.

[0017] The commutator 24 is coaxially provided on one end of the rotating shaft 21. The commutator 24 is rotatable in the circumferential direction Dc integrally with the rotating shaft 21. A brush 25 supported by a casing contacts the commutator 24 in the radial direction Dr, facing the commutator 24.

[0018] <Stator 3> The stator 3 is disposed on the outer circumferential side in the radial direction Dr with a gap (air gap) therebetween with respect to the rotor core 22. The stator 3 is fixed to the inner circumferential side in the radial direction Dr of the casing. The stator 3 has a stator core and a plurality of magnetic pole portions (neither of which are shown).

[0019] <Details of Rotor 2> The rotor 2 will now be described in more detail. As shown in FIG. 2, rotor core 22 integrally includes an annular portion 34 and a plurality of teeth 35. The annular portion 34 is formed on the inner peripheral side (the rotating shaft 21 side) of the rotor core 22. The annular portion 34 extends in the circumferential direction Dc, and is formed in an annular shape when viewed from the axial direction Da.

[0020] The teeth 35 are formed at equal intervals in the circumferential direction Dc. Each tooth 35 extends from the outer periphery of the annular portion 34 toward the outer periphery along the radial direction Dr. A slot 36 is formed between adjacent teeth 35 in the circumferential direction Dc. The slot 36 is formed by cutting out the outer periphery of the rotor core 22.

[0021] The slots 36 and the teeth 35 are formed in the same number (eight in this embodiment). The rotor core 22 may be configured to be divisible in the circumferential direction Dc for each of the teeth 35. A line Ct in the figure indicates a central axis line along the central axis line of the teeth 35 (the protruding direction of the teeth 35 (the motor radial direction Dr)). Hereinafter, the protruding direction of the teeth 35 is referred to as a teeth axial direction Dt1, and the direction perpendicular to the teeth axial direction Dt1 is referred to as a teeth radial direction Dt2.

[0022] The winding 32 is a conductive wire (e.g., copper wire) and is held by the rotor core 22 in the form of a coil 37. The winding 32 is wound around each of the multiple teeth 35 via an insulator 38 made of insulating resin. When viewed from the teeth axis direction Dt1, the winding 32 is wound in multiple layers around the outer periphery of the teeth 35. By winding the winding 32 around each tooth 35, multiple coils 37 are formed in the rotor 2 and arranged at intervals in the circumferential direction Dc. A slot pole (insulating plate) 39 made of insulating resin such as PPS is inserted between a pair of coils 37 adjacent to each other in the circumferential direction Dc.

[0023] <Insulator 38> 2, the insulator 38 has a flange-shaped outer peripheral piece 41 provided at one end side (motor outer peripheral side) in the teeth axis direction Dt1, a flange-shaped inner peripheral piece 42 provided at the other end side (motor inner peripheral side) in the teeth axis direction Dt1, and a cylindrical side wall portion (winding portion) 43 connecting the outer peripheral piece 41 and the inner peripheral piece 42 to each other. The internal space surrounded on three sides by the opposing surfaces of the outer peripheral piece 41 and the inner peripheral piece 42 and the outer surface of the winding portion 43 is a storage portion 45 that stores the coil 37 formed by stacking the windings 32. A pair of storage portions 45 adjacent to each other in the motor circumferential direction Dc form a slot 36. The windings 32 are densely arranged in the storage portion 45 in a so-called bale-pile manner.

[0024] <Filling with Varnish W> As shown in Figs. 2 and 3, the slot pole 39 is a rectangular flat plate along the motor radial direction Dr and the motor axial direction Da. The slot pole 39 insulates a pair of adjacent coils 37 in the motor circumferential direction Dc and fixes the position of each coil 37. In particular, unlike the stator 3 fixed to the casing, the wound field type rotor 2 rotates, so the coils 37 need to be fixed to prevent the windings from scattering due to centrifugal force. Between both sides of the slot pole 39 in the motor circumferential direction Dc and the coil 37 adjacent to the slot pole 39, an uneven gap is formed due to the unevenness of the outermost layer of the coil 37. The varnish W (shown dripping toward the rotor 2 in Fig. 3) is filled to fill this gap.

[0025] For example, if the windings of coil 37 are wound along the teeth axis direction Dt1, a conceivable method is to insert a wedge-shaped member into the space between coils 37 and fill the tiny gap between this member and coil 37 with varnish W, molding resin, or the like. On the other hand, if a tapered winding is adopted in which the number of turns of the coil 37 is increased toward the outside in the motor radial direction Dr as in the embodiment, the unevenness of the outermost layer of the coil 37 becomes non-uniform, and the gap between the slot pole 39 and the coil 37 becomes large. Therefore, even if the varnish W is simply filled at the arrangement position of the slot pole 39, there is a risk that a part of it will leak out to the outside of the rotor 2, resulting in insufficient filling of the varnish W. Furthermore, filling by molding requires additional processes and a sealing structure, which increases costs.

[0026] In the embodiment, in order to reliably fill the varnish W even if the gap between the slot pole 39 and the coil 37 is large, a foamed insulating sheet (e.g., foamed insulating paper, for example, a PEN (polyethylene naphthalate) film-based material having foamed adhesive layers on both sides) 39a is utilized.

[0027] 3, the foamed insulation sheet 39a is disposed only at one end of the slotted pole 39 in the motor axial direction Da. The foamed insulation sheet 39a is disposed on both sides of the slotted pole 39 in the motor circumferential direction Dc. The foamed insulation sheet 39a is attached to the slotted pole 39 in advance with epoxy resin or the like, and is inserted between a pair of coils 37 adjacent to each other in the motor circumferential direction Dc from the outside toward the inside in the motor radial direction Dr in an electric component assembly process S1 described later.

[0028] Thereafter, in a sheet foaming step S6 described later, the foamed insulation sheet 39a is foamed on both sides of the end of the slot pole 39 on one side in the motor axial direction Da. This allows large and small gaps between the slot pole 39 and the coil 37 to be filled at the end of the slot pole 39 on one side in the motor axial direction Da. At the end of the slot pole 39 on the other side in the motor axial direction Da, the gap between the slot pole 39 and the coil 37 is open, so that the varnish W can be filled from the other side in the motor axial direction Da at the arrangement position of the slot pole 39. At this time, the varnish W is blocked by the foamed insulation sheet 39a at the one side in the motor axial direction Da of the arrangement position of the slot pole 39, and the filled varnish W is prevented from leaking out from the one side in the motor axial direction Da.

[0029] <Manufacturing method of rotor 2> As shown in FIG. 4, the manufacturing method of the rotor 2 of the embodiment includes an electrical component assembly process S1, a pole insertion process S2, a first heating process S3, a first varnish dripping process S4, a first varnish hardening process S5, a sheet foaming process S6, a second varnish dripping process S7, and a second varnish hardening process S8.

[0030] In the electric component assembly process S1, an annular rotor 2 is obtained in which a coil 37 is formed on each of a plurality of teeth 35 aligned in the motor circumferential direction Dc. The electric component assembly process S1 includes a shaft press-fitting process S1a in which the rotating shaft 21 is press-fitted into the rotor core, an insulator setting process S1b in which an insulator 38 is attached to each tooth 35 of the rotor core, and a winding process S1c in which a winding is wound around the winding portion 43 of the insulator 38 to form the coil 37.

[0031] In the pole insertion process S2, the slotted pole 39 is inserted between a pair of coils 37 adjacent to each other in the motor circumferential direction Dc of the rotor 2. When the slotted pole 39 is assembled to the rotor 2, foamed insulating sheets 39a cut into strips of a specified width are attached in advance to both sides of one end of the slotted pole 39 in the motor axial direction Da with an epoxy adhesive or the like.

[0032] In the first heating step S3, the rotor 2 into which the slot pole 39 is inserted after the pole insertion step S2 is placed in a first heating furnace at a temperature (e.g., 120°C±10°C) lower than the temperature at which the foamed insulation sheet 39a foams (e.g., 180°C±10°C) and heated. The temperature of the first heating furnace is set to a temperature that reduces the viscosity of the varnish W to facilitate its penetration into the coil 37.

[0033] In the first varnish dripping step S4, varnish W is dripped onto each coil 37 from the other side of the rotor 2 in the motor axial direction Da after the first heating step S3. The amount of varnish W dripped may be preset to an amount that allows each coil 37 to completely permeate. By permeating each coil 37 with varnish W, the spaces between the windings 32 and the transition parts are fixed. The varnish W dripped onto each coil 37 is permeated and retained in each coil 37, and thus is prevented from leaking out of the rotor 2.

[0034] In the first varnish hardening step S5, the rotor 2 after the first varnish dripping step S4 is placed back into the first heating furnace to harden the varnish W dropped in the first varnish dripping step. Hardening of the varnish W requires, for example, heating at 120°C±10°C for 60 to 70 minutes. The first heating step S3 to the first varnish hardening step S5 can be carried out by keeping the first heating furnace at a constant temperature of 120°C±10°C, and energy consumption from using a heating furnace can be reduced.

[0035] In the sheet foaming step S6, the rotor 2 after the first varnish hardening step S5 is placed in a second heating furnace at a higher temperature (for example, 180°C±10°C) than the first heating furnace to foam the foamed insulation sheet 39a. The second heating furnace is configured to use the same equipment as the first heating furnace with a different set temperature, but may be configured to use equipment different from the first heating furnace. For example, heating at 180°C±10°C for 10 to 20 minutes is required to foam the foamed insulation sheet 39a. The foamed insulation sheet 39a foams on both sides of the end of one side of the slot pole 39 in the motor axial direction Da, thereby filling the gap between the slot pole 39 and the coil 37. The foamed insulation sheet 39a is not provided in the region other than the end of one side of the slot pole 39 in the motor axial direction Da, and this region can be filled with varnish W from the other side of the motor axial direction Da.

[0036] In the second varnish dripping process S7, varnish W is dripped onto the arrangement positions of each slotted pole 39 from the other side in the motor axial direction Da of the rotor 2 after the sheet foaming process S6. The amount of varnish W dripped may be set in advance to an amount that can fill the gaps around each slotted pole 39. The varnish W dripped onto the arrangement positions of each slotted pole 39 is prevented from leaking out from the one side in the motor axial direction Da of the rotor 2 by providing the foamed insulating sheet 39a at the end of the slotted pole 39 on the one side in the motor axial direction Da.

[0037] In the second varnish hardening step S8, the rotor 2 after the second varnish dripping step S7 is placed again in the second heating furnace to harden the varnish W dripped in the second varnish dripping step S7. The second heating furnace is used after the second varnish dripping step S7 by lowering the set temperature to 120°C ± 10°C, which is the same as that of the first heating furnace. In the second varnish hardening step S8, the first heating furnace may be used instead of the second heating furnace.

[0038] <Temperature history of rotor 2 manufacturing process> 5(a) shows a temperature history of the entire process of filling the rotor 2 with varnish W in the manufacturing process of the rotor 2 according to the embodiment. In this example, the first heating furnace and the second heating furnace are configured as the same heating furnace with different set temperatures. In the figure, range A indicates the range in which the first heating furnace is heated, range B indicates the range in which the first heating furnace is maintained at the specified temperature (120°C ± 10°C), range C indicates the range in which the second heating furnace is heated, range D indicates the range in which the second heating furnace is maintained at the specified temperature (180°C ± 10°C), and range E indicates the range in which the second heating furnace is cooled (natural heat dissipation). In the embodiment, the temperature throughout the process increases until the sheet foaming step S6 (range D), and decreases after the sheet foaming step S6.

[0039] 5(b) shows the temperature history of the rotor manufacturing process of the comparative example. In this comparative example, after the pole insertion process, the sheet foaming process is performed without dripping the varnish W, and the foamed insulation sheet 39a is foamed first to fill the gaps around the slot pole 39, and then the varnish W is filled (permeated into the coil 37). In the process of the comparative example, the foaming temperature of the foamed insulation sheet 39a is higher than the hardening temperature of the varnish W, so the rotor 2 is cooled once after foaming the foamed insulation sheet 39a. After that, the rotor 2 is heated again to a temperature suitable for the penetration of the varnish W, and the varnish W is filled in appropriate locations. For this reason, the energy required to complete the filling of the varnish W is increased by the temperature difference T when the rotor 2 is reheated to a temperature suitable for the penetration of the varnish W after cooling the rotor 2.

[0040] In contrast, in the embodiment, before the sheet foaming process S6, which has the highest set temperature, the temperature of the rotor 2 and the equipment is raised stepwise while a process of permeating the varnish W into each coil 37 is performed, and after the sheet foaming process S6, the temperature of the rotor 2 and the equipment is lowered stepwise while a process of filling the varnish W at the arrangement position of the slot pole 39 is performed. This eliminates the loss of raising the temperature once it has been lowered as in the comparative example, and makes it possible to reduce the energy required until filling of the varnish W is completed.

[0041] As described above, the manufacturing method of the rotating electric machine in the above embodiment is a manufacturing method of the motor 1 (rotor 2) in which a winding is wound around each of a plurality of teeth 35 aligned in the motor circumferential direction Dc to form a plurality of coils 37, and a plate-shaped slot pole 39 that provides insulation between a pair of coils 37 adjacent to each other in the motor circumferential direction Dc is disposed between the pair of coils 37, the manufacturing method including an electric component assembly process S1 for obtaining an annular rotor 2 in which a coil 37 is formed on each of a plurality of teeth 35 aligned in the motor circumferential direction Dc; a pole insertion process S2 for inserting a slot pole 39 having a foamed insulating sheet 39a affixed only to one end on one side in the motor axial direction Da between a pair of coils 37 adjacent to each other in the motor circumferential direction Dc in the rotor 2; and a first heating process S3 for heating the rotor 2 with the slot pole 39 inserted therein at a temperature lower than the temperature at which the foamed insulating sheet 39a foams. a first heating step S3 in which the rotor 2 is placed in a furnace and heated; a first varnish dripping step S4 in which varnish W is dripped onto each coil 37 from the other side of the motor shaft direction Da of the rotor 2 after the first heating step S3; a first varnish hardening step S5 in which the rotor 2 after the first varnish dripping step S4 is placed again in the first heating furnace and the varnish W dripped in the first varnish dripping step S4 is hardened; a sheet foaming step S6 in which the rotor 2 after the first varnish hardening step S5 is placed in a second heating furnace which is hotter than the first heating furnace and the foamed insulation sheet 39a is foamed; a second varnish dripping step S7 in which varnish W is dripped at arrangement positions of each slot pole 39 from the other side of the motor shaft direction Da of the rotor 2 after the sheet foaming step S6; and a second varnish hardening step S8 in which the rotor 2 after the second varnish dripping step S7 is placed again in the second heating furnace and the varnish W dripped in the second varnish dripping step S7 is hardened.

[0042] According to this configuration, in the rotor 2 having a plurality of teeth 35 and coils 37 arranged in the motor circumferential direction Dc, a slot pole 39 with a foamed insulating sheet 39a attached only to one end in the motor axial direction Da is inserted between a pair of coils 37 adjacent to each other in the motor circumferential direction Dc. After the electric component assembly process S1, the rotor 2 is preheated in a first heating furnace at a relatively low temperature, and then the varnish W is dripped onto each coil 37 to allow it to penetrate, and then the rotor 2 is placed again in the first heating furnace to harden the varnish W. In this way, by applying the varnish W only to each coil 37, the amount of varnish W used is reduced compared to a configuration in which the rotor 2 is immersed in a dip tank to apply the varnish W. In addition, by reducing the application of the varnish W around the coils 37, the coils 37 can be easily pushed out or pulled out when the rotor 2 is disassembled. In addition, by continuously using the first heating furnace at a relatively low temperature in the early stages of the manufacturing process of the rotor 2, the energy required from preheating the rotor 2 to hardening the varnish W can be reduced. After the varnish W dropped onto the coil 37 is hardened, the rotor 2 is placed in a second heating furnace, which is hotter than the first heating furnace, to foam the foamed insulation sheet 39a. This closes the gap between the coil 37 and the slot pole 39 around the end of the slot pole 39 on one side in the motor axial direction Da. Thereafter, the varnish W is dropped onto the arrangement portion of the slot pole 39 from the other side in the motor axial direction Da, so that the varnish W can be filled around the slot pole 39 while preventing the dropped varnish W from leaking out from the one side in the motor axial direction Da. The varnish W filled around the slot pole 39 is hardened by placing the rotor 2 again in the second heating furnace. At this time, the varnish W can be hardened by utilizing the residual heat of the second heating furnace. In this way, by setting the process of filling the rotating electric machine with the varnish W in order of increasing temperature up to the sheet foaming process S6 and then in order of decreasing temperature after the sheet foaming process S6, it is possible to prevent insufficient filling of the varnish W while reducing the energy required to complete filling of the varnish W.

[0043] The present invention is not limited to the above-described embodiment. For example, the manufacturing method of the rotating electric machine of the embodiment may be applied to a rotating electric machine other than a vehicle drive motor. For example, the rotating electric machine illustrated in the embodiment is an inner rotor type motor, but is not limited to this configuration. For example, the rotating electric machine may be an outer rotor type in which the rotor is disposed on the outer periphery side of the stator. Furthermore, the rotating electric machine is not limited to a motor, and may be a generator. Electrical heating of the winding 32 of the rotor 2 may be used to heat and foam the foamed insulating paper. In this case, large equipment such as a heating furnace is not required. The configurations in the above-described embodiments are merely examples of the present invention, and various modifications are possible without departing from the gist of the present invention, such as replacing the components of the embodiments with well-known components. [Explanation of symbols]

[0044] 1 Motor (rotating electric machine) 2 Rotor (electrical parts) 21 Rotation axis 22 Rotor core 32 windings 35 Teeth 36 Slots 37 Coil 38 Insulator 39 Slot Pole 39a Foam insulation sheet Da Axial direction (motor axis direction) Dc Circumferential direction (motor circumferential direction) Dr Radial direction (motor radial direction) Dt1 Teeth axial direction Dt2 Teeth radial direction S1 Electrical parts assembly process S2 Pole insertion process S3 First heating process S4 First varnish dripping process S5 First varnish curing process S6 Sheet foaming process S7 Second varnish dripping process S8 Second varnish curing process W Varnish

Claims

[Claim 1] A plurality of coils are formed by winding wires around each of a plurality of teeth arranged in the circumferential direction of the motor, A method for manufacturing a rotating electric machine in which a plate-shaped slot pole is disposed between a pair of coils adjacent to each other in a circumferential direction of the motor, the plate-shaped slot pole providing insulation between the pair of coils, the method comprising the steps of: an electric component assembly process for obtaining an annular electric component in which the coil is formed on each of the plurality of teeth arranged in the circumferential direction of the motor; a pole insertion process of inserting the slot pole, the slot pole having a foamed insulating sheet attached only to one end portion of the slot pole in the motor axial direction, between a pair of coils adjacent to each other in the motor circumferential direction of the electric component; a first heating step of heating the electrical component with the slotted pole inserted therein in a first heating furnace having a temperature lower than the temperature at which the foamed insulation sheet foams; a first varnish dripping step of dripping varnish onto each coil from the other axial side of the electric component after the first heating step; a first varnish hardening step in which the electrical component after the first varnish dropping step is placed again in the first heating furnace to harden the varnish dropped in the first varnish dropping step; a sheet foaming step in which the electrical component after the first varnish hardening step is placed in a second heating furnace having a temperature higher than that of the first heating furnace to foam the foamed insulation sheet; a second varnish dripping step of dripping the varnish onto positions of the slot poles from the other side of the electric component in the motor axial direction after the sheet foaming step; a second varnish hardening step in which the electrical component after the second varnish dropping step is placed again in the second heating furnace to harden the varnish dropped in the second varnish dropping step; A manufacturing method for a rotating electric machine comprising the steps of:

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