Stator and motor

Abstract

To provide a stator capable of improving productivity.SOLUTION: A stator is an inner rotor type stator, and includes: an annular stator core having a slot S which is recessed to outside in a diameter direction from the inside in the diameter direction; a coil having a conducting wire 122A arranged inside the slot; a sheet-like first insulation member arranged between the conducting wire and the stator core; a sheet-like second insulation member 126 of which at least a part is arranged inward in a radial direction than the first insulation member within the slot; and an impregnant 127 which is at least impregnated between the stator core and the second insulation member, and between the second insulation member and the conducting wire. The second insulation member has a plurality of layers, which are at least partly laminated in the radial direction. A layer which is arranged radially at the most inner side, among the plurality of layers, is a resin layer 1262. At least a part of the resin layer is exposed to the radial inner side via the slot.SELECTED DRAWING: Figure 7

Description

[Technical Field]

[0001] The present invention relates to a stator and a motor. [Background technology]

[0002] Conventionally, it is known that motors mounted on electric vehicles, hybrid vehicles, and the like are provided with the following stators. The stator has a stator core including teeth arranged in the circumferential direction. Slots are arranged between adjacent teeth. Coil conductors are arranged within the slots, and insulating paper is arranged to insulate the conductors from the stator core. Furthermore, the coil and insulating paper are impregnated with varnish to secure the coil and insulating paper to the stator core while insulating them from each other (see, for example, Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2015-35920 Summary of the Invention [Problem to be solved by the invention]

[0004] However, in conventional stators, the varnish would adhere to areas other than the desired locations on the insulating paper during the varnish impregnation process, necessitating the removal of the varnish. Therefore, there was room for improvement in the productivity of stators by improving the workability of this removal process.

[0005] An object of the present disclosure is to provide a stator that can improve productivity. [Means for solving the problem]

[0006] An exemplary stator according to the present disclosure is an inner rotor type stator, comprising: an annular stator core having slots recessed radially from the inside to the outside; coils having conductors disposed within the slots; a sheet-like first insulating member disposed between the conductors and the stator core; a sheet-like second insulating member disposed within the slots, at least a portion of which is disposed radially inward of the first insulating member; and an impregnating agent impregnated at least between the stator core and the second insulating member and between the second insulating member and the conductors. The second insulating member has multiple layers, at least a portion of which is stacked radially. The radially innermost layer of the multiple layers is a resin layer. At least a portion of the resin layer is exposed radially inward through the slots. [Effects of the Invention]

[0007] The exemplary stator of the present disclosure allows for improved productivity. [Brief explanation of the drawings]

[0008] [Figure 1] FIG. 1 is a cross-sectional view of an electric drive device according to an embodiment. [Figure 2] FIG. 2 is a perspective view of one axial end of the stator. [Figure 3] FIG. 3 is a perspective view of the stator core. [Figure 4] FIG. 4 is a partially enlarged view showing the configuration of the stator around the slots. [Figure 5] FIG. 5 is a flowchart illustrating an example of a method for manufacturing a stator. [Figure 6] FIG. 6 shows an example of a coil formed in the manufacturing process of a stator. [Figure 7] FIG. 7 is a partial cross-sectional view of the stator. [Figure 8] FIG. 8 is a view of the slot as viewed from the radially inner side toward the radially outer side. [Figure 9]FIG. 9 shows a diagram (upper) of the developed second insulating member as viewed from the radially inner side toward the radially outer side, and a cross-sectional view (lower) of the second insulating member taken along line II. [Figure 10] FIG. 10 is a cross-sectional view taken along line II showing a modified example of the layer structure of the second insulating member. [Figure 11] FIG. 11 shows an expanded view (upper) of the second insulating member according to the first modified example when viewed from the radially inner side toward the radially outer side, and a cross-sectional view (lower) of the second insulating member taken along line II. [Figure 12] FIG. 12 is a view of the second insulating member according to the second modified example, viewed from the radially inner side toward the radially outer side. [Figure 13] FIG. 13 is a view of the second insulating member according to the third modified example, viewed from the radially inner side toward the radially outer side. [Figure 14] FIG. 14 is a view of the second insulating member according to the fourth modified example, viewed from the radially inner side toward the radially outer side. [Figure 15] FIG. 15 is a view of the second insulating member according to the fifth modified example, viewed from the radially inner side toward the radially outer side. DETAILED DESCRIPTION OF THE INVENTION

[0009] Exemplary embodiments will now be described with reference to the drawings.

[0010] In this specification, the direction parallel to the central axis CA of the motor 100 in the electric drive device 700 is referred to as the "axial direction." Within the axial direction, the direction from the second shaft 110b to the first shaft 110a (described later) is referred to as the "one axial direction," and the direction from the first shaft 110a to the second shaft 110b is referred to as the "other axial direction."

[0011] Additionally, the direction perpendicular to the central axis CA is called the "radial direction," and the rotational direction around the central axis CA is called the "circumferential direction." Within the radial direction, the direction approaching the central axis CA is called the "radially inward direction," and the direction away from the central axis CA is called the "radially outward direction."

[0012] In addition, in this specification, "annular" includes not only a shape that is continuous and uninterrupted around the entire circumferential direction centered on the central axis CA, but also a shape that has an interstices along part of the entire circumference centered on the central axis CA.

[0013] <1. Electric drive unit configuration> An electric drive unit 700 according to the embodiment is mounted on a vehicle using a motor 100 as a drive source, such as a hybrid electric vehicle (HEV), a plug-in hybrid electric vehicle (PHV), or an electric vehicle (EV), and is used as a drive source for rotating the wheels of the vehicle. Fig. 1 is a cross-sectional view of the electric drive unit 700 according to the embodiment. Note that Fig. 1 shows the cross-sectional structure of the electric drive unit 700 taken along a plane including the central axis CA of the motor 100.

[0014] As shown in FIG. 1, the electric drive unit 700 includes a motor 100, a reduction gear 200, a differential gear (not shown), and a housing 400. The housing 400 has a motor housing 401 that houses the motor 100, a reduction gear housing 402 that houses the reduction gear 200, and a differential housing (not shown) that houses the differential gear. The motor 100 is driven by three-phase AC. The reduction gear 200 is connected to the motor 100 and amplifies the torque transmitted from the motor 100 at a predetermined reduction ratio before transmitting it to the differential gear. The differential gear is connected to the motor 100 via the reduction gear 200 and transmits the torque transmitted from the reduction gear 200 to the wheels.

[0015] <2. Motor configuration> As shown in FIG. 1, the motor 100 includes a rotor 11 and a stator 12.

[0016] The rotor 11 is disposed radially inward of the stator 12 and is rotatable in the circumferential direction about a central axis CA. That is, the motor 100 is an inner rotor type motor and includes the stator 12 and the rotor 11 disposed radially inward of the stator 12. The stator 12 is an inner rotor type stator. The rotor 11 includes a shaft 110, a rotor core 111, and a magnet 112.

[0017] The shaft 110 is the rotation axis of the rotor 11. The shaft 110 is rotatably supported by the motor housing 401 via bearings (reference numeral omitted). The shaft 110 has a first shaft 110a, a second shaft 110b, and a first gear portion 110c. The first shaft 110a and the second shaft 110b are hollow cylindrical and extend in the axial direction. One axial end of the second shaft 110b is connected to the other axial end of the first shaft 110a. The first gear portion 110c is a gear that meshes with the second gear portion 210 of the reduction gear transmission 200 and transmits the driving force of the motor 100 to the reduction gear transmission 200. The first gear portion 110c is provided on the radially outer surface of the second shaft 110b. The second shaft 110b protrudes from the motor housing 401 in the other axial direction. Therefore, the other axial side portion of the second shaft 110b and the first gear portion 110c are housed within the reduction housing 402.

[0018] The rotor core 111 is an annular magnetic body centered on a central axis CA, and in this embodiment is a laminated body formed by stacking a plurality of plate-shaped electromagnetic steel sheets. The rotor core 111 is fixed to the radially outer surface of the first shaft 110a. The rotor core 111 has a plurality of through holes 1111 that penetrate the rotor core 111 in the axial direction. The through holes 1111 are arranged at intervals in the circumferential direction.

[0019] The magnet 112 has a plurality of magnet pieces (not shown). Each magnet piece has a flat plate shape that extends in a direction perpendicular to the radial direction, and is held in each through-hole 1111 of the rotor core 111. In other words, the magnet pieces are arranged at intervals in the circumferential direction.

[0020] The stator 12 drives and rotates the rotor 11. The stator 12 is annular and has a central axis CA as its center. Fig. 2 is a perspective view of one axial end of the stator 12.

[0021] The stator 12 includes a stator core 121, a coil 122, interphase paper 123, a binding member 124, a first insulating member 125 (shown in FIG. 4 described later), and a second insulating member 126 (shown in FIG. 4 described later).

[0022] Fig. 3 is a perspective view of the stator core 121. The stator core 121 is an annular magnetic body centered on a central axis CA, and in this embodiment is a laminated body in which a plurality of plate-shaped electromagnetic steel sheets are stacked. As shown in Fig. 3, the stator core 121 has an annular core back 1211, a plurality of teeth 1212, and a plurality of slots S.

[0023] The multiple teeth 1212 extend radially inward from the radially inner end of the core back 1211 and are lined up in the circumferential direction. Slots S are provided between adjacent teeth in the circumferential direction. The multiple slots S are provided at the radially inner end of the annular stator core 121 and are lined up in the circumferential direction. The slots S are spaces that are recessed radially outward from the radially inner end face of the stator core 121 and extend in the axial direction. The slots S are open radially inward. In other words, the stator 12 has an annular stator core 121 that has slots S recessed from the radially inner to the radially outward.

[0024] 4 is a partially enlarged view showing the configuration around the slots S in the stator 12. FIG. 4 shows a schematic configuration of one axial end of the stator core 121.

[0025] The conductor 122A of the coil 122 is disposed inside the slot S. That is, the stator 12 has the coil 122 having the conductor 122A disposed inside the slot S. A first insulating member 125 formed of an insulating material is disposed inside the slot S. The first insulating member 125 is a sheet-like member extending in the axial direction, also called slot paper, and is folded so as to protrude radially outward and is accommodated inside the slot S. Both axial ends of the first insulating member 125 protrude axially outward from the stator core 121. The first insulating member 125 surrounds the conductor 122A from the radially outward and both circumferential sides, providing insulation between the conductor 122A and the stator core 121. That is, the stator 12 has the sheet-like first insulating member 125 disposed between the conductor 122A and the stator core 121.

[0026] A second insulating member 126, also called wedge paper, is disposed inside the slot S. The second insulating member 126 is a sheet-like member extending in the axial direction and is folded so as to convex radially inward and accommodated inside the slot S. Both axial ends of the second insulating member 126 protrude axially outward from the stator core 121. Both ends of the second insulating member 126, spaced apart from the apex of the radially outward convex portion along the second insulating member 126, overlap with a portion of the first insulating member 125. The remaining portion of the second insulating member 126 is disposed radially inward from the first insulating member 125. The second insulating member 126 surrounds the conductor 122A from the radially inward and both circumferential sides, providing insulation between the conductor 122A and the stator core 121. That is, the stator 12 has a sheet-like second insulating member 126, at least a portion of which is disposed radially inward from the first insulating member 125 inside the slot S. The second insulating member 126 will be described in more detail later.

[0027] Each coil 122 is provided across different slots S. In this embodiment, the multiple coils 122 are single-layer lap-wound using a distributed winding method. More specifically, each coil 122 is a U-phase coil, a V-phase coil, or a W-phase coil. In this embodiment, the coils of each phase are Y-connected. Coils of the same phase are electrically connected via a crossover wire or bus bar (not shown). The coils 122 of the same phase are housed in a slot S that is spaced apart from multiple slots S that house coils 122 of the other two phases using a distributed winding method. Furthermore, using a single-layer lap-winding method, each slot S houses a coil 122 of the same phase. In other words, coils 122 of different phases are not housed in the same slot S.

[0028] In this embodiment, a round wire having a circular cross section is used for the conductor 122A of the coil 122. However, this is not limiting, and a conductor having a cross section other than a circular shape may be used. For example, the cross section of the conductor may be a polygonal shape such as a rectangle or a hexagon.

[0029] Each coil 122 has a coil end 1221. The coil end 1221 is a portion that protrudes outward from the slot S of the coil 122, and is provided on one axial side of one axial end of the stator core 121 and on the other axial side of the other axial end of the stator core 121.

[0030] The interlayer paper 123 is provided to electrically insulate the different coils 122 from one another, and has a structure in which nonwoven paper is attached to both sides of a thin resin plate, for example.

[0031] The bundling member 124 is in the form of an insulating string, and binds the conductor wires of the coil end 1221 together.

[0032] 3. Stator manufacturing method Next, a description will be given of a method for manufacturing the stator 12. Fig. 5 is a flowchart for explaining an example of a method for manufacturing the stator 12.

[0033] First, a conductor wire is wound around a jig having a longitudinal direction to form a coil shape, thereby forming the coils 122 (S1). In this embodiment, half the total number of coils 122 in the slots S are formed. As shown in FIG. 6, for example, the coils 122 are formed into a shape having coil ends 1221 at both ends in the longitudinal direction and a pair of straight portions 1222 extending in the longitudinal direction. The pair of straight portions 1222 includes a first straight portion 1222a and a second straight portion 1222b. In this case, as shown in FIG. 6, the coil shape perpendicular to the extension direction dL of each coil 122 is formed into a hexagonal shape having a longitudinal direction in this embodiment. However, the coil shape is not limited to this example and may be, for example, an elliptical shape having a longitudinal direction.

[0034] Next, the first insulating member 125 is attached to the stator core 121 (S2). At this time, the first insulating member 125 is inserted into the slot S. FIG. 4 shows the state in which the first insulating member 125 is inserted into the slot S. As shown in FIG. 4, the first insulating member 125 extends in the axial direction, bends along the inner wall of the slot S, and has a shape that opens radially inward. Furthermore, the first insulating member 125 protrudes from the slot S on one axial side and the other axial side.

[0035] Next, two coils 122 of the same phase are attached to the stator core 121 in order (S3). First, the straight portions 1222 of each of the two coils 122 of the same phase are arranged radially inward of the slots S that house the straight portions 1222, at the same circumferential position as the slots S. At this time, the straight portions 1222 are aligned so as to be housed in the corresponding slots S. Then, each straight portion 1222 is pushed radially outward to be inserted into the corresponding slots S. In this way, the coils 122 are provided across different slots S.

[0036] After all the coils 122 are attached to the stator core 121, second insulating members (wedge paper) 126 are inserted into each slot S (S4). As shown in Fig. 4, the second insulating members 126 extend in the axial direction, bend along the inner wall of the slot S, and open radially outward. The second insulating members 126 also protrude from the slots S on one axial side and the other axial side.

[0037] Next, the interphase paper 123 is sandwiched between the coil ends 1221 of the coils 122 of different phases that are adjacent in the circumferential direction (S5).

[0038] Next, the coil ends 1221 with the interlayer paper 123 provided between them are pressed in the axial direction (S6). That is, the coil ends 1221 on one axial side of the stator 12 are pressed in the other axial direction together with one interlayer paper 123, and are molded so as to have a lower axial height. Also, the coil ends 1221 on the other axial side of the stator 12 are pressed in the one axial direction together with the other interlayer paper 123, and are molded so as to have a lower axial height.

[0039] Next, in order to prevent the conductors of the coil ends 1221 from coming apart, the pressed coil ends 1221 are bound together with the interfacing paper 123 by binding members 124 (S7).

[0040] Next, an impregnating agent is injected into the coil ends 1221 on one axial side and the other axial side using a jig (S8). For example, a varnish is used as the impregnating agent. For example, WP-2820 (GN) (manufactured by Showa Denko Materials Co., Ltd. (formerly Hitachi Chemical Co., Ltd.)) can be used as the varnish. The impregnating agent is injected while the stator core 121 is rotated around the central axis CA. The injected impregnating agent penetrates into the axial center of the stator core 121 due to capillary action. The impregnating agent hardens after impregnation.

[0041] <4. Insulating materials> Next, a detailed description will be given of the configuration of the second insulating member (wedge paper) 126. In the following drawings, the radially inner side is indicated as R1, the radially outer side is indicated as R2, one axial side is indicated as Z1, the other axial side is indicated as Z2, and the circumferential direction is indicated as θ.

[0042] 7 is a partial cross-sectional view of stator 12 taken along a plane perpendicular to the axial direction at an intermediate position in the axial direction. For convenience, part of conductor 122A disposed inside slot S and first insulating member 125 are not shown in FIG.

[0043] 7, the second insulating member 126 has a two-layer structure in which an aramid layer 1261 and a resin layer 1262 are laminated. The second insulating member 126 is bent along the inner wall of the slot S with the aramid layer 1261 side facing outward in the radial direction and placed inside the slot S. That is, the second insulating member 126 has multiple layers 1261, 1262, at least some of which are laminated in the radial direction, and the radially innermost layer of the multiple layers is the resin layer 1262.

[0044] The aramid layer 1261 is manufactured by a process using a paper machine or the like. No surface treatment is performed on the aramid layer 1261 and the resin layer 1262, and in the state where no surface treatment is performed, the resin layer 1262 has a surface roughness that makes it more difficult for an impregnating agent to adhere than the aramid layer 1261. Specific examples of the materials of the aramid layer 1261 and the resin layer 1262 will be described later.

[0045] 7, the aforementioned impregnating agent application process causes impregnating agent 127 to be impregnated between teeth 1212 and second insulating member 126, and between second insulating member 126 and conducting wire 122A. That is, stator 12 has impregnating agent 127 impregnated at least between stator core 121 and second insulating member 126, and between second insulating member 126 and conducting wire 122A.

[0046] 8 is a view of the slot S viewed from the radially inner side toward the radially outer side. As shown in FIGS. 7 and 8, a portion 1262P of the resin layer 1262 is exposed radially inward through a radially inner end portion SA included in the slot S. That is, at least a portion of the resin layer 1262 is exposed radially inward through the slot S.

[0047] Therefore, the resin layer 1262, which has a surface roughness that makes it difficult for the impregnating agent to adhere, is provided on the radially innermost layer of the second insulating member 126, and at least a portion of the resin layer 1262 is exposed radially inward through the slots S. This prevents the impregnating agent from adhering to the exposed portions (1262P) of the resin layer 1262 during the impregnating agent application process after the second insulating member 126 is attached. A process for removing the impregnating agent adhering to the exposed portions of the resin layer 1262 is performed to prevent the impregnating agent from contacting the rotor 11. The suppression of impregnating agent adhesion and the surface roughness of the resin layer 1262 that makes it difficult for the impregnating agent to adhere facilitate the removal of the impregnating agent. This improves the productivity of the stator 12. This also improves the productivity of the motor 100 having the stator 12.

[0048] If the second insulating member 126 were placed inside the slot S with the resin layer 1262 radially outward and the aramid layer 1261 radially inward, a portion of the aramid layer 1261 would be exposed radially inward from the slot S. The impregnating agent would likely adhere to the aramid layer 1261, making it easier for the impregnating agent to adhere to the exposed portion. Therefore, the amount of impregnating agent adhering to the exposed portion would increase, and the exposed portion would have surface roughness that makes it easier for the impregnating agent to adhere, making it difficult to remove the impregnating agent. This could result in a decrease in productivity of the stator 12. Furthermore, because the resin layer 1262 is placed radially outward, it would be difficult for the impregnating agent to penetrate between the second insulating member 126 and the conducting wire 122A, where the impregnating agent is desired to adhere.

[0049] Figure 9 shows a view (top) of the second insulating member 126 unfolded with the resin layer 1262 facing radially inward, viewed from radially inward to radially outward, and a cross-sectional view (bottom) of the second insulating member 126 taken along line II.

[0050] The cross-sectional view II shown in FIG. 9 illustrates a specific example of a two-layer structure of the second insulating member 126. In the two-layer structure shown in FIG. 9, the resin layer 1262 includes a resin layer 1262A and a resin layer 1262B. The resin layer 1262A and the resin layer 1262B are bonded together by an adhesive layer 1263 made of an adhesive. The aramid layer 1261 and the resin layer 1262A are bonded together by an adhesive layer 1264. The resin layer 1262A and the resin layer 1262B are formed of the same material, but are formed of a different resin than the aramid layer 1261. In this specification, when multiple layers made of the same material, such as the resin layers 1262A and 1262B, are bonded together by an adhesive layer, the multiple layers are considered to be one layer. Thus, the second insulating member 126 shown in FIG. 9 has a two-layer structure including the aramid layer 1261 and the resin layer 1262.

[0051] That is, as described above, second insulating member 126 has multiple layers 1261, 1262, at least a portion of which is laminated in the radial direction (FIG. 7). The multiple layers are two layers: aramid layer 1261 and resin layer 1262 that is different from aramid layer 1261. This makes it possible to ensure the strength of second insulating member 126 while also making it thinner.

[0052] It is desirable that the aramid layer 1261 be made of Nomex (registered trademark), and the resin layer 1262 be made of PPS (polyphenylene sulfaroid). By using Nomex, which has excellent heat resistance and strength, for the aramid layer 1261 and PPS, which is resistant to adhesion of the impregnating agent, for the resin layer 1262, it is possible to achieve both durability of the second insulating member 126 and suppression of adhesion of the impregnating agent.

[0053] As the PPS, for example, Torelina (registered trademark) can be adopted. Note that the resin layer 1262 is not limited to PPS, and may be made of PEI (polyetherimide), PET (polyethylene terephthalate), PEN (polyethylene naphthalate), or the like.

[0054] In addition, if there are few restrictions on the thickness of one resin layer in manufacturing, a resin layer 1262 of a desired thickness may be formed from one resin layer, as shown in the cross-sectional view II of FIG.

[0055] The second insulating member 126 may have a layer structure of three or more layers. The layers of the second insulating member 126 may be directly bonded together without using adhesive or the like. By making the second insulating member 126 have a layer structure of multiple layers, it is possible to suppress the growth of cracks even if the surface of the second insulating member 126 is scratched. Furthermore, the adhesive layer bonding the layers together can improve oil resistance.

[0056] <5. First Modification> Next, we will explain a first modified example of the second insulating member 126. Figure 11 shows the second insulating member 126 according to the first modified example, unfolded with the resin layer 1262 facing radially inward, as viewed from radially inward to radially outward (top), and a cross-sectional view of the second insulating member 126 taken along line II (bottom).

[0057] 11 , a portion made up of resin layer 1262 and adhesive layers 1263 and 1264 protrudes radially inward from the circumferential center of aramid layer 1261. The portion made up of resin layer 1262 and adhesive layers 1263 and 1264 is provided over the entire axial direction of aramid layer 1261. Note that this portion may also be provided over a portion of aramid layer 1261 in the axial direction.

[0058] That is, when the second insulating member 126 in the unfolded state shown in FIG. 11 is viewed from the radially inner side toward the radially outer side, at least a portion of the resin layer 1262 is disposed at the circumferential center of the second insulating member 126, and the aramid layer 1261 is disposed on both circumferential sides of the resin layer 1262 disposed at the circumferential center.

[0059] The portions of the second insulating member 126 exposed radially inward through the slots S are portions where it is undesirable for the impregnating agent to adhere. Therefore, the resin layer 1262, to which the impregnating agent does not easily adhere in the circumferential direction, is limited to the circumferential center, and aramid layers 1261, to which the impregnating agent easily adheres, are provided on both circumferential sides of the resin layer 1262 without providing any resin layers. This makes it possible to improve the impregnation rate of the impregnating agent.

[0060] <6. Second Modification> Next, we will explain a second modified example of the second insulating member 126. Fig. 12 is a diagram of the second insulating member 126 according to the second modified example, viewed from the radially inner side toward the radially outer side, with the resin layer 1262 facing radially inward.

[0061] 12, a portion made up of resin layer 1262 and adhesive layers 1263 and 1264 protrudes radially inward from the axial center of aramid layer 1261. The portion made up of resin layer 1262 and adhesive layers 1263 and 1264 is provided over the entire circumferential direction of aramid layer 1261. Note that this portion may also be provided over a portion of aramid layer 1261 in the circumferential direction.

[0062] That is, when the second insulating member 126 in the unfolded state shown in FIG. 12 is viewed from the radially inner side toward the radially outer side, at least a portion of the resin layer 1262 is disposed at the axial center of the second insulating member 126, and the aramid layers 1261 are disposed on both axial sides of the resin layer 1262 disposed at the axial center.

[0063] The impregnating agent is injected from both axial sides of the stator 12 using a jig, and penetrates into the axial center of the stator 12 by capillary action. The gap between the stator core 121 and the resin layer 1262 arranged at the axial center of the second insulating member 126 is narrower than the gap between the stator core 121 and the aramid layers 1261 arranged on both axial sides of the resin layer 1262, so the impregnating agent easily penetrates into the axial center by capillary action. This makes it possible to improve the impregnation rate or impregnation speed.

[0064] <7.Third Modification> Next, we will explain a third modified example of the second insulating member 126. Fig. 13 is a diagram of the second insulating member 126 according to the third modified example, viewed from the radially inner side toward the radially outer side, with the resin layer 1262 facing radially inward.

[0065] In the expanded state of second insulating member 126 shown in FIG. 13, portions consisting of resin layer 1262 and adhesive layers 1263, 1264 protrude radially inward from one axial end and the other axial end of aramid layer 1261, respectively.

[0066] That is, when the second insulating member 126 in the expanded state shown in FIG. 13 is viewed from the radially inner side toward the radially outer side, at least a portion of the resin layer 1262 is arranged at both axial ends of the second insulating member 126, and the aramid layer 1261 is arranged in the axial direction between the resin layers 1262 arranged at both axial ends.

[0067] The impregnating agent is injected from both axial ends of the stator 12 and penetrates toward the axial center. By arranging the resin layers 1262 at both axial ends of the second insulating member 126, the gap between the second insulating member 126 and the stator core 121 at both axial ends is narrowed, making it easier for the impregnating agent to penetrate toward the axial center without being confined to both axial ends.

[0068] <8. Fourth Variation> Next, we will explain a fourth modified example of the second insulating member 126. Fig. 14 is a diagram of the second insulating member 126 according to the fourth modified example, viewed from the radially inner side toward the radially outer side, with the resin layer 1262 facing radially inward.

[0069] In the unfolded state of second insulating member 126 shown in Fig. 14, portions made up of resin layer 1262 and adhesive layers 1263 and 1264 protrude radially inward from the circumferential center and the axial center of aramid layer 1261. As a result, when second insulating member 126 in the unfolded state shown in Fig. 14 is viewed from the radially inner side toward the radially outer side, resin layer 1262 extending in the axial direction intersects with resin layer 1262 extending in the circumferential direction at the center of aramid layer 1261. According to such a fourth modified example, it is possible to obtain the same effects as those of the first and second modified examples.

[0070] <9. Fifth Variation> Next, we will explain a fifth modified example of the second insulating member 126. Fig. 15 is a diagram of the second insulating member 126 according to the fifth modified example, viewed from the radially inner side toward the radially outer side, with the resin layer 1262 facing radially inward.

[0071] 15, portions made up of resin layer 1262 and adhesive layers 1263 and 1264 protrude radially inward from the circumferential center, axial center, both axial ends, and both circumferential ends of aramid layer 1261. This provides the same effects as those of the first, second, and third modifications.

[0072] 15 , when the second insulating member 126 in the expanded state is viewed from the radially inner side toward the radially outer side, at least a portion of the resin layer 1262 is disposed at both circumferential ends of the second insulating member 126, and the aramid layer 1261 is disposed in the circumferential direction between the resin layers 1262 disposed at both circumferential ends. As a result, when the second insulating member 126 is attached to the stator core 121, even if the circumferential ends of the second insulating member 126 come into contact with the stator core 121, the resin layer 1262, which has a smoother surface roughness than the aramid layer 1261, comes into contact with the stator core 121. Therefore, the circumferential ends of the second insulating member 126 can easily slide relative to the stator core 121. This makes it easy to attach the second insulating member 126 to the slot S.

[0073] <10.Other> The embodiments of the present disclosure have been described above. Note that the scope of the present disclosure is not limited to the above-described embodiments. The present disclosure can be implemented by adding various modifications to the above-described embodiments without departing from the spirit of the invention. Furthermore, the matters described in the above-described embodiments can be combined in any appropriate manner as long as no contradiction occurs. [Industrial Applicability]

[0074] The present disclosure can be used, for example, in an in-vehicle motor. [Explanation of symbols]

[0075] 11 rotor 12 Stator 100 motor 110 Shaft 111 rotor core 112 Magnet 121 stator core 122 Coil 122A conductor 123 Aima paper 124 Binding member 125 First insulating member 126 Second insulating member 127 Impregnating Agent 200 Reducer 400 Housing 700 Electric Drive Unit 1211 Coreback 1212 Teeth 1221 Coil end 1222 Straight section 1261 Aramid layer 1262 Resin layer 1262A,1262B Resin layer 1263,1264 Adhesive layer CA center axis S slot SA radial inner end

Claims

1. An inner rotor type stator, an annular stator core having slots recessed from the radially inner side to the radially outer side; a coil having a conductor disposed within the slot; a sheet-like first insulating member disposed between the conductor and the stator core; a sheet-like second insulating member at least a portion of which is disposed radially inward from the first insulating member within the slot; an impregnating agent impregnated at least between the stator core and the second insulating member and between the second insulating member and the conductor; and the second insulating member has a plurality of layers at least some of which are stacked in the radial direction, the radially innermost layer of the plurality of layers is a resin layer, At least a portion of the resin layer is exposed radially inward through the slot, the plurality of layers are two layers, an aramid layer and a resin layer different from the aramid layer, The resin layer includes a first resin layer and a second resin layer made of the same resin material, and the first resin layer and the second resin layer are joined by an adhesive layer made of an adhesive.

2. An inner rotor type stator, an annular stator core having slots recessed from the radially inner side to the radially outer side; a coil having a conductor disposed within the slot; a sheet-like first insulating member disposed between the conductor and the stator core; a sheet-like second insulating member at least a portion of which is disposed radially inward from the first insulating member within the slot; an impregnating agent impregnated at least between the stator core and the second insulating member and between the second insulating member and the conductor; and the second insulating member has a plurality of layers at least some of which are stacked in the radial direction, the radially innermost layer of the plurality of layers is a resin layer, At least a portion of the resin layer is exposed radially inward through the slot, the plurality of layers are two layers, an aramid layer and a resin layer different from the aramid layer, When the second insulating member is unfolded with the resin layer facing radially inward, as viewed from the radially inward direction toward the radially outward direction, At least a portion of the resin layer is disposed at a circumferential center of the second insulating member, the aramid layers are disposed on both sides in the circumferential direction of the resin layer disposed at the circumferential center of the stator.

3. An inner rotor type stator, an annular stator core having slots recessed from the radially inner side to the radially outer side; a coil having a conductor disposed within the slot; a sheet-like first insulating member disposed between the conductor and the stator core; a sheet-like second insulating member at least a portion of which is disposed radially inward from the first insulating member within the slot; an impregnating agent impregnated at least between the stator core and the second insulating member and between the second insulating member and the conductor; and the second insulating member has a plurality of layers at least some of which are stacked in the radial direction, the radially innermost layer of the plurality of layers is a resin layer, At least a portion of the resin layer is exposed radially inward through the slot, the plurality of layers are two layers, an aramid layer and a resin layer different from the aramid layer, When the second insulating member is unfolded with the resin layer facing radially inward, as viewed from the radially inward direction toward the radially outward direction, At least a portion of the resin layer is disposed at the axial center of the second insulating member, the aramid layers are disposed on both axial sides of the resin layer disposed at the axial center of the stator.

4. An inner rotor type stator, an annular stator core having slots recessed from the radially inner side to the radially outer side; a coil having a conductor disposed within the slot; a sheet-like first insulating member disposed between the conductor and the stator core; a sheet-like second insulating member at least a portion of which is disposed radially inward from the first insulating member within the slot; an impregnating agent impregnated at least between the stator core and the second insulating member and between the second insulating member and the conductor; and the second insulating member has a plurality of layers at least some of which are stacked in the radial direction, the radially innermost layer of the plurality of layers is a resin layer, At least a portion of the resin layer is exposed radially inward through the slot, the plurality of layers are two layers, an aramid layer and a resin layer different from the aramid layer, When the second insulating member is unfolded with the resin layer facing radially inward, as viewed from the radially inward direction toward the radially outward direction, At least a portion of the resin layer is disposed on both axial ends of the second insulating member, The aramid layer is disposed axially between the resin layers disposed at both ends in the axial direction.

5. An inner rotor type stator, an annular stator core having slots recessed from the radially inner side to the radially outer side; a coil having a conductor disposed within the slot; a sheet-like first insulating member disposed between the conductor and the stator core; a sheet-like second insulating member at least a portion of which is disposed radially inward from the first insulating member within the slot; an impregnating agent impregnated at least between the stator core and the second insulating member and between the second insulating member and the conductor; and the second insulating member has a plurality of layers at least some of which are stacked in the radial direction, the radially innermost layer of the plurality of layers is a resin layer, At least a portion of the resin layer is exposed radially inward through the slot, the plurality of layers are two layers, an aramid layer and a resin layer different from the aramid layer, When the second insulating member is unfolded with the resin layer facing radially inward, as viewed from the radially inward direction toward the radially outward direction, At least a portion of the resin layer is disposed on both circumferential ends of the second insulating member, The aramid layer is disposed in a circumferential direction between the resin layers disposed at both ends in the circumferential direction.

6. The aramid layer is made of Nomex®, 6. The stator according to claim 1, wherein the resin layer is made of PPS (polyphenylene sulfide).

7. The stator according to any one of claims 1 to 6, a rotor disposed radially inward of the stator; A motor having

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