Stator and motor

Abstract

The stator (2) is disposed inside the housing (3) of the electric motor (1), and includes a stator core (20), a coil (21) formed by winding a winding around the stator core (20) and having coil ends (21a) protruding in the axial direction from both axial end faces of the stator core (20), and two thermally conductive resin parts (22) provided on both axial end faces of the stator core (20) and covering the coil ends (21a). A notch (22h) cut from the outside to the inside in the radial direction is formed on the outer peripheral surface (22g) of at least one of the two thermally conductive resin parts (22). The notch (22h) is formed in a part of the outer peripheral surface (22g) of the thermally conductive resin part (22) in the axial and circumferential directions, and opens to the stator core (20) side of both axial end faces of the thermally conductive resin part (22).

Description

[Technical field]

[0001] The present disclosure relates to a stator and an electric motor including a stator core and a coil. [Background technology]

[0002] Conventionally, a stator including a cylindrical stator core and a coil is known. The coil is formed by winding a winding around the stator core. The coil has a coil end. The coil end is a portion of the coil that protrudes in the axial direction from an end face of the stator core in the axial direction. The coil end is covered with a resin part.

[0003] The stator is disposed inside a cylindrical housing. The housing has an insertion hole for disposing the stator therein. When disposing the stator inside the housing during manufacture of the electric motor, it is necessary to determine the axial position of the housing relative to the stator.

[0004] Patent Document 1 describes a technique for axially positioning the housing relative to the stator by providing an exposed surface exposed from the resin part on the outer periphery of the axial end face of the stator core and bringing this exposed surface into contact with a stepped surface provided on the inner periphery of the insertion hole of the housing. The exposed surface is formed by making the outer diameter of the entire resin part smaller than the outer diameter of the stator core, or by providing a notch penetrating the outer periphery of the resin part in the axial direction. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] International Publication No. 2022 / 045166 Summary of the Invention [Problem to be solved by the invention]

[0006] However, in the technology disclosed in Patent Document 1, when the exposed surface is formed by making the outer diameter of the entire resin part smaller than the outer diameter of the stator core, the outer peripheral surface of the resin part does not come into contact with the housing. Also, in the technology disclosed in Patent Document 1, when the exposed surface is formed by providing a notch penetrating the outer peripheral surface of the resin part in the axial direction, the size of the notch becomes large and it is not possible to ensure a sufficient contact area between the outer peripheral surface of the resin part and the housing. Therefore, in either case, the heat generated from the coil is less likely to be transmitted to the housing through the resin part, resulting in a problem of reduced cooling performance for the coil.

[0007] The present disclosure has been made in consideration of the above, and aims to obtain a stator that can position the housing in the axial direction relative to the stator and suppress a decrease in cooling performance for the coil. [Means for solving the problem]

[0008] In order to solve the above problems and achieve the object, the stator according to the present disclosure is a stator disposed inside a housing of an electric motor, and includes a stator core, a coil formed by winding a winding around the stator core and having coil ends protruding in the axial direction from both axial end faces of the stator core, and two thermally conductive resin parts provided on both axial end faces of the stator core and covering the coil ends. A notch cut from the outside to the inside in the radial direction is formed on the outer peripheral surface of at least one of the two thermally conductive resin parts. The notch is formed in a part of the outer peripheral surface of the thermally conductive resin part in the axial and circumferential directions, and opens to the stator core side of both axial end faces of the thermally conductive resin part. A portion of at least one of both axial end faces of the stator core is exposed through the notch. Effect of the Invention

[0009] The stator according to the present disclosure has the advantage that it is possible to determine the axial position of the housing relative to the stator, and also to suppress a decrease in cooling performance for the coil. [Brief description of the drawings]

[0010] [Figure 1] FIG. 1 is a cross-sectional view showing an electric motor including a stator according to a first embodiment, taken along an axial direction; [Diagram 2] FIG. 1 is a side view showing a stator according to a first embodiment; [Diagram 3] FIG. 1 is a side view showing a stator according to a first embodiment, illustrating an example of a cutout in the first embodiment. [Figure 4] FIG. 1 is a side view showing the stator according to the first embodiment, illustrating another example of a cutout in the first embodiment; [Diagram 5] FIG. 11 is a side view showing a stator according to a second embodiment, illustrating an example of a cutout in the second embodiment; [Figure 6] FIG. 11 is a side view showing the stator according to the second embodiment, illustrating another example of a cutout in the second embodiment; [Figure 7] FIG. 11 is a side view showing a stator according to a third embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0011] Hereinafter, a stator and an electric motor according to an embodiment will be described in detail with reference to the drawings.

[0012] Embodiment 1 1 is a cross-sectional view showing an electric motor 1 including a stator 2 according to a first embodiment, taken along the axial direction. The electric motor 1 includes a stator 2, a housing 3, a rotor 4, and two brackets 5. A stator core 20 of the stator 2, which will be described later, is formed in a cylindrical shape having a central axis C. In the following description of the directions of each component of the electric motor 1, the direction parallel to the central axis C is referred to as the axial direction, the direction perpendicular to the central axis C is referred to as the radial direction, and the direction of rotation about the central axis C is referred to as the circumferential direction.

[0013] The housing 3 is formed in a cylindrical shape with both ends in the axial direction being open. The housing 3 is formed with an insertion hole 30 for arranging the stator 2. The housing 3 is formed with a hole 31 for inserting a positioning pin 7. The hole 31 penetrates the side wall of the housing 3 in the radial direction. The hole 31 is arranged at a position that coincides with one notch 22h described later in the axial direction. In other words, the hole 31 is arranged at a position that faces one notch 22h in the radial direction. The pin 7 is a member for axially positioning the housing 3 with respect to the stator 2 when arranging the stator 2 inside the housing 3, and is not a component of the electric motor 1, but the pin 7 is also illustrated in FIG. 1 for convenience of explanation.

[0014] The rotor 4 is disposed on the inner circumference of the stator 2. The rotor 4 is provided with a shaft portion 6 extending along the central axis C of the stator 2. The brackets 5 are disposed at one end and the other end of the housing 3 in the axial direction. Each bracket 5 has a bearing 60 that rotatably supports the shaft portion 6 of the rotor 4. The shaft portion 6 of the rotor 4 is rotatably supported by the two bearings 60.

[0015] The stator 2 is disposed inside the housing 3 of the electric motor 1. The stator 2 includes a stator core 20, a plurality of coils 21, two thermally conductive resin parts 22, and a plurality of lead wires 23.

[0016] The stator core 20 is formed in a cylindrical shape. The stator core 20 is configured to include, for example, a laminate of rolled steel sheets or electromagnetic steel sheets stacked in the axial direction. The stator core 20 is formed with a through hole 20a extending in the axial direction. The rotor 4 is disposed in the through hole 20a. The stator core 20 has a plurality of teeth 20b. The plurality of teeth 20b are radially disposed about the central axis C.

[0017] Each of the multiple coils 21 is formed by winding a wire around the stator core 20. A coil 21 is formed by winding a wire around each of the teeth portions 20b. Each coil 21 has two coil ends 21a that protrude in the axial direction from both axial end faces of the stator core 20. The coil ends 21a protrude in the axial direction away from the axial center of the stator core 20 along the axial direction.

[0018] Hereinafter, when it is necessary to distinguish between the coil end 21a protruding in the axial direction from one axial end face 20c of the stator core 20 and the coil end 21a protruding in the axial direction from the other axial end face 20d of the stator core 20, they will be referred to as the first coil end 21b and the second coil end 21c. Note that in Fig. 1, the portion of each coil 21 located between the two coil ends 21a is omitted from illustration.

[0019] The lead wires 23 electrically connect the coils 21 to a power supply unit (not shown). One end of the lead wires 23 in the length direction is connected to the power supply unit, and the other end of the lead wires 23 in the length direction is connected to a terminal portion (not shown) of the coils 21. Power is supplied to each coil 21 from the power supply unit via the lead wires 23. The length of the lead wires 23 is not limited to the example shown in the figures, and may be changed as appropriate.

[0020] The thermally conductive resin portion 22 is provided on each of both axial end faces (one end face 20c and the other end face 20d) of the stator core 20. The thermally conductive resin portion 22 is formed in a cylindrical shape. The thermally conductive resin portion 22 is formed by molding. The material of the thermally conductive resin portion 22 is a resin having thermal conductivity. Examples of such resins include thermosetting resins such as epoxy resin. The thermally conductive resin portion 22 may contain a filler or the like.

[0021] The thermally conductive resin part 22 covers the coil end 21a. The thermally conductive resin part 22 covers the entire coil end 21a. The thermally conductive resin part 22 plays a role in transferring heat generated from the coil 21 to the housing 3. The heat generated from the coil 21 is transferred to the thermally conductive resin part 22. The heat transferred to the thermally conductive resin part 22 is transferred to the housing 3. A cooling medium such as cooling oil (not shown) flowing around the outer periphery of the housing 3 absorbs the heat transferred to the housing 3. As a result, the coil 21 is cooled by the cooling medium via the thermally conductive resin part 22 and the housing 3.

[0022] The outer peripheral surface 22g of the thermally conductive resin portion 22 is a surface facing the housing 3 in the radial direction. The thermally conductive resin portion 22 has a first thermally conductive resin portion 22a and a second thermally conductive resin portion 22b. The first thermally conductive resin portion 22a is provided on one end surface 20c in the axial direction of the stator core 20. The first thermally conductive resin portion 22a covers the first coil ends 21b of the multiple coils 21. The second thermally conductive resin portion 22b is provided on the other end surface 20d in the axial direction of the stator core 20. The second thermally conductive resin portion 22b covers the second coil ends 21c of the multiple coils 21. The first thermally conductive resin portion 22a and the second thermally conductive resin portion 22b may be formed of the same resin or different resins.

[0023] The first thermally conductive resin part 22a is provided with a lead wire 23 for electrically connecting the coil 21 to a power supply part (not shown). The first thermally conductive resin part 22a has a first outer axial end face 22c facing away from the stator core 20 and a first inner axial end face 22d facing toward the stator core 20. The first outer axial end face 22c and the first inner axial end face 22d are flat surfaces extending in the radial direction. The first inner axial end face 22d is a surface that contacts the stator core 20. The first inner axial end face 22d contacts one end face 20c of the stator core 20 in the axial direction. The first inner axial end face 22d is located at the boundary between the first thermally conductive resin part 22a and the stator core 20.

[0024] The second thermally conductive resin part 22b has a second outer axial end face 22e facing away from the stator core 20, and a second inner axial end face 22f facing toward the stator core 20. The second outer axial end face 22e and the second inner axial end face 22f are flat surfaces extending in the radial direction. The second inner axial end face 22f is a surface that contacts the stator core 20. The second inner axial end face 22f contacts the other axial end face 20d of the stator core 20. The second inner axial end face 22f is located at the boundary between the second thermally conductive resin part 22b and the stator core 20.

[0025] FIG. 2 is a side view showing the stator 2 according to the first embodiment. FIG. 3 is a side view showing the stator 2 according to the first embodiment, showing an example of the notch 22h in the first embodiment. FIG. 4 is a side view showing the stator 2 according to the first embodiment, showing another example of the notch 22h in the first embodiment. FIG. 3 and FIG. 4 are views of the stator 2 from an angle different from that of FIG. 2. As shown in FIG. 2, a notch 22h is formed in an outer peripheral surface 22g of the first thermally conductive resin part 22a of the two thermally conductive resin parts 22, the notch 22h being cut from the outside to the inside in the radial direction. The notch 22h is formed in a part of the outer peripheral surface 22g of the first thermally conductive resin part 22a in the axial direction and the circumferential direction, and is open to the stator core 20 side of both axial end faces of the first thermally conductive resin part 22a. That is, the notch 22h does not penetrate the outer peripheral surface 22g of the first thermally conductive resin part 22a in the axial direction and the circumferential direction. The number of the notches 22h is two in this embodiment, but may be changed as appropriate. The two notches 22h are arranged at equal angles (180 degrees apart in this embodiment). Hereinafter, a portion of the outer peripheral surface 22g of the first thermally conductive resin part 22a where no notches 22h are formed in the circumferential direction and where the outer diameter of the outer peripheral surface 22g is constant over the entire circumferential length is referred to as a "reference portion 22i."

[0026] The shape of the notch 22h when viewed in the radial direction is not particularly limited, and may be a rectangle as shown in Fig. 3 or a circle (perfect circle) as shown in Fig. 4. The outer diameter D2 of the reference portion 22i shown in Fig. 2 is the same as the outer diameter D1 of the stator core 20 in this embodiment, but is preferably smaller than the outer diameter D1 of the stator core 20. The outer diameter D3 of the portion of the outer peripheral surface 22g of the first thermally conductive resin portion 22a including the notch 22h is smaller than the outer diameter D1 of the stator core 20 and the outer diameter D2 of the reference portion 22i.

[0027] Next, the effects of the stator 2 and the electric motor 1 according to this embodiment will be described.

[0028] In this embodiment, as shown in Fig. 2, a notch 22h is formed in the outer peripheral surface 22g of the first thermally conductive resin part 22a of the two thermally conductive resin parts 22, which is cut from the outside to the inside in the radial direction. In addition, in this embodiment, the notch 22h is formed in a part of the outer peripheral surface 22g of the first thermally conductive resin part 22a in the axial and circumferential directions, and opens on the stator core 20 side of both axial end faces of the first thermally conductive resin part 22a. With these configurations, a part of one axial end face 20c of the stator core 20 is exposed from the first thermally conductive resin part 22a through the notch 22h, so that when the stator 2 is disposed inside the housing 3 shown in Fig. 1, the pin 7 inserted through the hole 31 of the housing 3 is placed against this exposed part, thereby allowing the axial positioning of the housing 3 relative to the stator 2 to be performed. That is, when stator 2 is disposed inside housing 3, the portion of one axial end face 20c of stator core 20 exposed from first thermally conductive resin portion 22a can be used as a positioning surface.

[0029] In addition, in this embodiment, because the notch 22h does not penetrate the outer peripheral surface 22g of the first thermally conductive resin part 22a in the axial and circumferential directions, the size of the notch 22h can be reduced to ensure a sufficient contact area between the outer peripheral surface 22g of the first thermally conductive resin part 22a and the housing 3. As a result, even if the first thermally conductive resin part 22a is provided with the notch 22h, the heat generated from the coil 21 is easily transferred to the housing 3 through the first thermally conductive resin part 22a, so that a decrease in the cooling performance for the coil 21 can be suppressed. Therefore, in this embodiment, the axial positioning of the housing 3 with respect to the stator 2 can be performed, and a decrease in the cooling performance for the coil 21 can be suppressed.

[0030] As a conventional technique for positioning the housing in the axial direction relative to the stator, for example, as disclosed in Japanese Patent No. 7333887, there is a technique for positioning the housing in the axial direction relative to the stator by providing recesses on the axial top and bottom surfaces of the resin part and contacting the recesses with a step surface provided on the inner peripheral surface of the insertion hole of the housing. The bottom surface of the recess becomes a positioning surface that contacts the step surface. However, since the conventional technique has a structure in which the entire axial end surface of the stator core is in contact with the resin part, there is a problem that the stator core cannot be supported by contacting a jig or the like with the axial end surface of the stator core when the mold resin is filled. In this respect, in the present embodiment, when the mold resin is filled, a part of a mold jig (not shown) is placed at the position where the notch 22h shown in FIG. 2 is formed, and a part of the mold jig is brought into contact with one axial end surface 20c of the stator core 20 to support the stator core 20. In the above-mentioned conventional technology, recesses are provided on the top and bottom surfaces in the axial direction of the resin part, and the axial end face of the stator core is not exposed, so that it is not possible to measure the dimensions between the axial end face of the stator core and the positioning face of the resin part. In addition, in the above-mentioned conventional technology, the positioning face is made of resin, and there is a large variation in dimensions due to the effect of shrinkage of the resin after molding, so that the dimensions between the axial end face of the stator core and the positioning face of the resin part are not accurately determined, and the positional relationship between the stator core and the rotor also varies greatly. Due to these factors, the above-mentioned conventional technology has a problem that it is difficult to align the stator and the rotor. In this regard, in the present embodiment, as shown in FIG. 1, a part of the axial end face 20c of the stator core 20 is exposed from the first thermally conductive resin part 22a through the notch 22h to become a positioning face, so that the position of the axial end face 20c of the stator core 20 and the housing 3 is accurately determined. This makes it easier to align the stator 2 with the rotor 4 held by the housing 3 via the bearing 60.

[0031] Next, a modification of this embodiment will be described.

[0032] In this embodiment, as shown in FIG. 2, the notch 22h is formed on the outer peripheral surface 22g of only the first thermally conductive resin part 22a, but it is sufficient that the notch 22h is formed on the outer peripheral surface 22g of at least one of the two thermally conductive resin parts 22.

[0033] Embodiment 2 Next, a stator 2A according to a second embodiment will be described with reference to Fig. 5 and Fig. 6. Fig. 5 is a side view showing a stator 2A according to the second embodiment, showing an example of a notch 22h in the second embodiment. Fig. 6 is a side view showing a stator 2A according to the second embodiment, showing another example of a notch 22h in the second embodiment. In this embodiment, the shape of the notch 22h is different from that in the first embodiment. In the second embodiment, the same reference numerals are used for parts that overlap with those in the first embodiment, and description thereof will be omitted.

[0034] In this embodiment, the shape of the cutout 22h when viewed in the radial direction is a semicircle as shown in Fig. 5 or a trapezoid as shown in Fig. 6. The cutout 22h shown in Fig. 5 is formed in a semicircle that is convex in the direction away from the stator core 20. The cutout 22h shown in Fig. 6 is formed in a trapezoid that is convex in the direction away from the stator core 20.

[0035] Next, the effects of the stator 2A according to this embodiment will be described.

[0036] In this embodiment, the shape of the cutout 22h when viewed in the radial direction is semicircular or trapezoidal, so that the flow of the molded resin is not hindered when the molded resin is sealed, and the occurrence of voids and cracks in the thermally conductive resin part 22 can be suppressed.

[0037] Embodiment 3 Next, a stator 2B according to a third embodiment will be described with reference to Fig. 7. Fig. 7 is a side view showing a stator 2B according to the third embodiment. This embodiment differs from the first embodiment in that a notch 22h is formed in each of the two thermally conductive resin parts 22. In the third embodiment, the same reference numerals are used for parts that overlap with the first embodiment, and description thereof will be omitted.

[0038] The configuration (the configuration of the coil 21, the lead wire 23, etc.) is the same as that of the above-mentioned embodiment 1 (see FIG. 1), except that the notch 22h is formed in each of the two thermally conductive resin parts 22. When one axial side of the stator 2 on which the lead wire 23 for electrically connecting the coil 21 to a power supply part (not shown) is arranged is defined as the connection side, and the opposite axial side to the connection side is defined as the anti-connection side, the notch 22h is formed in the first thermally conductive resin part 22a provided on the connection side and the second thermally conductive resin part 22b provided on the anti-connection side. That is, the notch 22h is provided on both sides of the stator 2 in the axial direction.

[0039] Next, the effects of the stator 2B according to this embodiment will be described.

[0040] In this embodiment, the notch 22h is formed in the first thermally conductive resin part 22a provided on the wiring side and the second thermally conductive resin part 22b provided on the non-wiring side, so that when the molded resin is filled, the molded resin can be filled from either end face side in the axial direction of the stator core 20, and the filling direction of the molded resin can be freely selected. This improves the workability when filling the molded resin.

[0041] The configurations shown in the above embodiments are merely examples, and may be combined with other known technologies, or the embodiments may be combined with each other. Also, parts of the configurations may be omitted or modified without departing from the spirit of the invention. [Explanation of symbols]

[0042] 1 electric motor, 2, 2A, 2B stator, 3 housing, 4 rotor, 5 bracket, 6 shaft portion, 7 pin, 20 stator core, 20a through hole, 20b teeth portion, 20c one end face, 20d other end face, 21 coil, 21a coil end, 21b first coil end, 21c second coil end, 22 thermally conductive resin portion, 22a first thermally conductive resin portion, 22b second thermally conductive resin portion, 22c first outer shaft end face, 22d first inner shaft end face, 22e second outer shaft end face, 22f second inner shaft end face, 22g outer peripheral surface, 22h notch, 22i reference portion, 23 lead wire, 30 insertion hole, 31 hole, 60 bearing, C central shaft, D1, D2, D3 outer diameter.

Claims

1. A stator located inside the housing of an electric motor, Stator core and A coil formed by winding a wire around the stator core, having coil ends that protrude in the axial direction from each of the axial end faces of the stator core, The stator core comprises two heat-conductive resin parts provided on each of the axial end faces and covering the coil ends, A notch is formed on the outer circumferential surface of at least one of the two heat-conductive resin parts, cutting out from the radially outer side toward the inner side. The aforementioned notches are formed in a part of the outer surface of the thermal conductive resin portion in the axial and circumferential directions, and open to the stator core side of both end faces of the thermal conductive resin portion in the axial direction. A stator characterized in that at least one of the axial end faces of the stator core is exposed through the notch.

2. The stator according to claim 1, characterized in that the shape of the notch when viewed along the radial direction is semicircular or trapezoidal.

3. When one side of the stator in the axial direction, where lead wires for electrically connecting the power supply unit and the coil are arranged, is designated as the connection side, and the side in the axial direction opposite to the connection side is designated as the non-connection side, The stator according to claim 1, characterized in that the notch is formed in the heat-conductive resin portion provided on the connection side and the heat-conductive resin portion provided on the non-connection side.

4. Housing and A stator according to any one of claims 1 to 3, disposed inside the housing, A rotor positioned on the inner circumference of the stator, An electric motor characterized by comprising: brackets having bearings disposed at one end and the other end of the housing in the axial direction, which rotatably support the rotor.

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