Manufacturing method of rotating 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 interior permanent magnet type. Wound field motors place coils on the rotor instead of permanent magnets, and generate magnetic flux in the rotor by passing current through these coils. 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 ring-shaped portion, a plurality of cores (teeth) protruding radially inward or outward from the ring-shaped portion, and a coil with a conducting wire wound around the outer periphery of each core. For example, Patent Document 1 discloses a method for manufacturing 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] Between adjacent coils in the circumferential direction of the motor, plate-like members (slot poles) are arranged to insulate the coils and fix their positions. The unevenness of the outermost layer of the coil's winding creates gaps of various sizes between the slot poles and the coils. Therefore, even if varnish is applied to the slot poles, some of the varnish may flow out of the gaps, resulting in insufficient varnish application.

[0006] In response to this problem, it has been considered to insert a foam insulation sheet together with a slot pole between the coils, foam the foam insulation sheet first to fill the gaps, and then fill the gaps with varnish. However, the foaming temperature of the foam insulation sheet is higher than the curing 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 varnish penetration before the varnish can be applied. This increases the energy required to complete the varnish application, and improvements are 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 improved 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 plurality of coils are formed by winding wires around each of a plurality of teeth aligned in the circumferential direction of the motor, and a plate-shaped slot pole is disposed between a pair of coils adjacent in the circumferential direction of the motor to provide insulation between the pair of coils, the method comprising 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 circumferential direction of the motor; a pole insertion process for inserting a slot pole having a foam insulation sheet affixed to only one end on one side in the axial direction of the motor between a pair of coils adjacent in the circumferential direction of the motor in the electric component; and a third heating process for heating the electric component with the inserted slot pole in a first heating furnace at a temperature lower than the temperature at which the foam insulation sheet foams. The method is characterized by comprising: 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 at the arrangement position of each 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 multiple teeth and coils arranged circumferentially, a slotted pole with a foam insulation sheet attached only to one end in the axial direction of the motor is inserted between a pair of adjacent coils in the circumferential direction of the motor. 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 and allowed to penetrate. The electric component is then placed back in the first heating furnace to harden the varnish. By applying varnish only to each coil in this manner, the amount of varnish used can be reduced compared to a configuration in which the electric component is immersed in a dip bath to apply varnish. Furthermore, by reducing the application of varnish around the coils, it is easier to push or pull out the coils when disassembling the electric component. Furthermore, by continuing to use the first heating furnace at a relatively low temperature in the early stages of the electric component manufacturing process, the energy required from preheating the electric component to hardening the varnish can be reduced. After the varnish dripped onto the coil hardens, the electrical component is placed in a second heating furnace, which is hotter than the first heating furnace, to foam the foam 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 axial direction of the motor. Then, by dripping varnish onto the slot pole from the other side in the axial direction of the motor, the dripped varnish can be prevented from leaking from the one side in the axial direction of the motor and the varnish can be filled around the slot pole. The electrical component is placed back into the second heating furnace, where the varnish is hardened. The residual heat from the second heating furnace can be used to harden the varnish. 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 the varnish while reducing the energy required to complete filling of the varnish. [Effects 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 explanation of the drawings]

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

[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 that uses a field winding (coil 37) instead of a permanent magnet. By passing a direct current through the field winding from an external source, the motor 1 generates a magnetic flux in the rotor 2 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 (neither of which are shown). The rotating shaft 21 is supported so as to be rotatable 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 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 arranged 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 a wire 32 around the outer periphery of a tooth 35 formed on the rotor core 22, with an insulator 38 interposed therebetween. Details of the coil 37 and the insulator 38 will be described later.

[0017] The commutator 24 is provided coaxially on one end of the rotary shaft 21. The commutator 24 is rotatable in the circumferential direction Dc integrally with the rotary shaft 21. Brushes 25 supported by a casing are in contact with the commutator 24 so as to face each other in the radial direction Dr.

[0018] <Stator 3> The stator 3 is disposed on the outer circumferential side in the radial direction Dr relative to the rotor core 22 with an air gap therebetween. 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, the 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 (rotary 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 number of slots 36 and the number of teeth 35 are the same (eight in this embodiment). The rotor core 22 may be configured to be divisible in the circumferential direction Dc for each set of teeth 35. In the drawing, line Ct indicates the central axis of the teeth 35 (the protruding direction of the teeth 35 (motor radial direction Dr)). Hereinafter, the protruding direction of the teeth 35 will be referred to as the teeth axial direction Dt1, and the direction perpendicular to the teeth axial direction Dt1 will be referred to as the teeth radial direction Dt2.

[0022] The winding 32 is a conducting wire (e.g., copper wire) and is held in 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, the rotor 2 is formed with multiple coils 37 spaced apart in the circumferential direction Dc. A slot pole (insulating plate) 39 made of insulating resin such as PPS is inserted between a pair of adjacent coils 37 in the circumferential direction Dc.

[0023] <Insulator 38> 2, the insulator 38 has a flange-shaped outer peripheral piece 41 provided at one end (on the outer periphery of the motor) in the teeth axis direction Dt1, a flange-shaped inner peripheral piece 42 provided at the other end (on the inner periphery of the motor) 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 serves as 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 forms a slot 36. The windings 32 are densely arranged in the storage portion 45 in a so-called rice-bag stacking manner.

[0024] <Filling with Varnish W> As shown in Figures 2 and 3, the slot pole 39 has a rectangular flat plate shape extending 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, which is fixed to the casing, the wound-field rotor 2 rotates, so the coils 37 must be fixed to prevent the windings from flying off 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, uneven gaps are formed due to the unevenness of the outermost layer of the coil 37. Varnish W (shown dripping toward the rotor 2 in Figure 3) is applied to fill these gaps.

[0025] For example, if the winding of coil 37 is wound along the tooth axis direction Dt1, one possible 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, etc. On the other hand, if a tapered winding is adopted in which the number of turns of the coil 37 increases 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 an attempt is made to simply fill the varnish W at the arrangement position of the slot pole 39, some of the varnish may 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 39a (e.g., foamed insulating paper, such as a PEN (polyethylene naphthalate) film as a base material with foamed adhesive layers on both sides) is utilized.

[0027] 3, the foam insulation sheet 39a is disposed only on one end of the slotted pole 39 in the motor axial direction Da. The foam insulation sheet 39a is disposed on both sides of the slotted pole 39 in the motor circumferential direction Dc. The foam 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 slotted pole 39 on one side in the motor axial direction Da. This makes it possible to fill large and small gaps between the slotted pole 39 and the coil 37 at the end of the slotted pole 39 on one side in the motor axial direction Da. At the end of the slotted pole 39 on the other side in the motor axial direction Da, the gap between the slotted 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 slotted 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 slotted pole 39, preventing the filled varnish W from leaking out from the one side in the motor axial direction Da.

[0029] <Method of manufacturing 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] The electric component assembly process S1 obtains an annular rotor 2 in which a coil 37 is formed on each of a plurality of teeth 35 aligned in the circumferential direction Dc of the motor. 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, a 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 with the slotted poles 39 inserted therein 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). The temperature of the first heating furnace is set to a temperature that reduces the viscosity of the varnish W and makes it easier for it to penetrate 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 shaft direction Da after the first heating step S3. The amount of varnish W dripped may be preset to an amount that allows the varnish W to completely permeate each coil 37. By permeating each coil 37 with varnish W, the spaces between the windings 32 and the transition sections are fixed. The varnish W dripped onto each coil 37 is permeated and retained in each coil 37, and therefore is prevented from leaking outside 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 dripped in the first varnish dripping step. Hardening the varnish W requires, for example, heating at 120°C ± 10°C for 60 to 70 minutes. The first heating step S3 through the first varnish hardening step S5 can be carried out by maintaining the first heating furnace at a constant temperature of 120°C ± 10°C, which reduces the energy consumption associated with using a heating furnace.

[0035] In the sheet foaming step S6, the rotor 2 after the first varnish hardening step S5 is placed in a second heating furnace heated to a temperature higher than that of the first heating furnace (e.g., 180°C ± 10°C) to foam the foamed insulation sheet 39a. The second heating furnace is configured using the same equipment as the first heating furnace, but the set temperature may be changed. Alternatively, a different equipment from the first heating furnace may be used. Foaming the foamed insulation sheet 39a requires heating at 180°C ± 10°C for 10 to 20 minutes, for example. The foamed insulation sheet 39a foams on both sides of the end of one side of the slotted pole 39 in the motor axial direction Da, thereby filling the gap between the slotted pole 39 and the coil 37. The foamed insulation sheet 39a is not provided in the area other than the end of one side of the slotted pole 39 in the motor axial direction Da, and this area 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 of the motor shaft 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 of the motor shaft direction Da of the rotor 2 by providing a foamed insulating sheet 39a at the end of the slotted pole 39 on the one side of the motor shaft direction Da.

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

[0038] <Temperature history during the manufacturing process of rotor 2> 5(a) shows the 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 up to 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 a comparative example. In this comparative example, after the pole insertion process, the sheet foaming process is performed without dripping or otherwise applying varnish W. The foamed insulation sheet 39a is first foamed to fill the gaps around the slot pole 39, and then the varnish W is filled in (permeating the coil 37). In the process of the comparative example, the foaming temperature of the foam insulation sheet 39a is higher than the hardening temperature of the varnish W, so the rotor 2 is cooled once after foaming the foam insulation sheet 39a. The rotor 2 is then heated again to a temperature suitable for the penetration of the varnish W, and the varnish W is then filled into 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 to this, 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 gradually increased while a process of permeating the varnish W into each coil 37 is carried out, and after the sheet foaming process S6, the temperature of the rotor 2 and the equipment is gradually decreased while a process of filling the varnish W at the arrangement positions of the slot poles 39 is carried out. 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 complete.

[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 assembling process S1 for obtaining an annular rotor 2 in which a coil 37 is formed on each of the plurality of teeth 35 aligned in the motor circumferential direction Dc; a pole inserting process S2 for inserting a slot pole 39 having a foamed insulating sheet 39a affixed only to one end of the rotor 2 in the motor axial direction Da between a pair of coils 37 adjacent to each other in the motor circumferential direction Dc; and a first heating process S3 for heating the rotor 2 with the inserted slot pole 39 at a temperature lower than the temperature at which the foamed insulating sheet 39a foams. a first varnish-curing step S5 in which the rotor 2 after the first varnish-curing step S4 is placed back into the first heating furnace to harden the varnish W dropped in the first varnish-curing step S4; a sheet-foaming step S6 in which the rotor 2 after the first varnish-curing step S5 is placed in a second heating furnace which is hotter than the first heating furnace to foam the foamed insulation sheet 39a; a second varnish-curing step S7 in which varnish W is dropped at the arrangement position 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-curing step S8 in which the rotor 2 after the second varnish-curing step S7 is placed back into the second heating furnace to harden the varnish W dropped in the second varnish-curing step S7.

[0042] According to this configuration, a rotor 2 has multiple teeth 35 and coils 37 aligned in the motor circumferential direction Dc. A slotted 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 adjacent coils 37 in the motor circumferential direction Dc. After the electrical component assembly process S1, the rotor 2 is preheated in a first heating furnace at a relatively low temperature. Then, varnish W is dripped onto each coil 37 and allowed to penetrate. The rotor 2 is then placed back into the first heating furnace to harden the varnish W. By applying varnish W only to each coil 37 in this manner, the amount of varnish W used is reduced compared to a configuration in which the rotor 2 is immersed in a dipping bath to apply varnish W. Furthermore, by reducing the application of varnish W around the coils 37, the coils 37 can be easily pushed out or pulled out during disassembly of the rotor 2. Furthermore, by continuing to use the first heating furnace at a relatively low temperature in the early stages of the rotor 2 manufacturing process, the energy required from preheating the rotor 2 to hardening the varnish W can be reduced. After the varnish W dripped onto the coil 37 hardens, the rotor 2 is placed in a second heating furnace, which is hotter than the first heating furnace, to foam the foam insulation sheet 39a. This closes the gap between the coil 37 and the slotted pole 39 around the end of the slotted pole 39 on one side in the motor axial direction Da. Then, by dripping varnish W onto the location of the slotted pole 39 from the other side in the motor axial direction Da, the dripped varnish W can be prevented from leaking from the one side in the motor axial direction Da and the varnish W can be filled around the slotted pole 39. The varnish W filled around the slotted pole 39 is hardened by placing the rotor 2 back into the second heating furnace. At this time, the varnish can be hardened using the residual heat from the second heating furnace. In this way, by setting the process of filling the rotating electric machine with 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 embodiments. For example, the manufacturing method of the rotating electric machine of the embodiments may be applied to rotating electric machines other than vehicle drive motors. For example, the rotating electric machine illustrated in the embodiments is an inner rotor 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 of the stator. Furthermore, the rotating electric machine is not limited to a motor, and may also be a generator. Electrical heating of the windings 32 of the rotor 2 may be used to heat and foam the foam 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 within the scope of 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 part) 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 having a foamed insulating sheet affixed only to one end 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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