Motor and manufacturing method thereof

Abstract

The present invention relates to a motor and a manufacturing method thereof, the motor comprising: a housing having a cylindrical inner peripheral surface; and a stator having an outer peripheral surface that comes into contact with the inner peripheral surface from the inside in the radial direction. The outer peripheral surface of the stator is provided with a plurality of grooves which extend in the axial direction and are arranged in the circumferential direction. The inner peripheral surface of the housing is provided with at least one protruding part which abuts against the inner surface of any one of the plurality of groove parts. The plurality of groove portions include at least one first groove portion in contact with the protruding portion, and a second groove portion not in contact with the protruding portion.

Description

Technical Field

[0001] The present disclosure relates to a motor and a method for manufacturing the same. Background Art

[0002] A motor is disclosed in Japanese Unexamined Patent Application Publication No. 2022-172196. The motor includes: a housing having a cylindrical inner peripheral surface; and a stator having an outer peripheral surface that abuts against the inner peripheral surface of the housing from the inner side in the radial direction.

[0003] The motor of Japanese Unexamined Patent Application Publication No. 2022-172196 further includes pins extending along the axial direction. By fitting the pins into the outer peripheral surface of the stator and the inner peripheral surface of the housing, the housing and the stator are positioned in the circumferential direction. Therefore, in the motor of Japanese Unexamined Patent Application Publication No. 2022-172196, it is necessary to accurately position the circumferential direction position of the outer peripheral surface of the stator and the circumferential direction position of the inner peripheral surface of the housing when manufacturing the motor. Summary of the Invention

[0004] The present disclosure provides a technique capable of easily positioning a housing and a stator in the circumferential direction.

[0005] According to one aspect of the present disclosure, a motor includes: a housing having a cylindrical inner peripheral surface; and a stator having an outer peripheral surface that abuts against the inner peripheral surface from the inner side in the radial direction. A plurality of groove portions are provided on the outer peripheral surface of the stator, extending along the axial direction and arranged along the circumferential direction. At least one protrusion that abuts against the inner surface of any one of the plurality of groove portions is provided on the inner peripheral surface of the housing. The plurality of groove portions include at least one first groove portion against which the protrusion abuts and a second groove portion against which the protrusion does not abut.

[0006] In the above configuration, the outer peripheral surface of the stator abuts against the inner peripheral surface of the housing from the inner side in the radial direction, and the housing holds the stator by the pressure applied from the housing to the stator. In such a structure, if the pressure applied to the stator is too large, the magnetic characteristics of the stator may unexpectedly change. Regarding this point, in the above configuration, a plurality of groove portions are formed on the outer peripheral surface of the stator, thereby moderately relaxing the pressure applied to the stator. In addition, the plurality of groove portions include a first groove portion provided with a protrusion provided on the housing and a second groove portion without such a protrusion. According to such a structure, when manufacturing the motor, the stress relaxation function can be exerted by the plurality of groove portions, and the housing and the stator can be easily positioned in the circumferential direction.

[0007] The protrusion and the first groove portion may be in partial contact with each other.

[0008] According to the above configuration, in the first groove portion that abuts against the protrusion of the housing, the pressure applied to the stator can also be intentionally relaxed.

[0009] The above-mentioned protrusion and the above-mentioned first groove portion can be in contact with each other as a whole.

[0010] According to the above configuration, the circumferential positioning of the housing and the stator can be accurately performed.

[0011] A plurality of the above-mentioned protrusions can be provided on the above-mentioned inner circumferential surface of the above-mentioned housing. The plurality of the above-mentioned protrusions can be arranged at equal intervals in the circumferential direction.

[0012] According to the above configuration, the alignment accuracy between the stator and the housing can be improved.

[0013] The plurality of the above-mentioned groove portions can be arranged at equal intervals in the circumferential direction.

[0014] According to the above configuration, the pressure acting on the stator can be averaged.

[0015] The above-mentioned protrusion can extend along the above-mentioned axial direction.

[0016] According to the above configuration, the alignment accuracy between the stator and the housing can be improved.

[0017] The above-mentioned protrusion can have a tapered section where the protruding height from the above-mentioned inner circumferential surface gradually increases as it approaches one side in the above-mentioned axial direction.

[0018] According to the above configuration, when assembling the housing and the stator, it is easy to position the protrusion of the housing with respect to the first groove portion of the stator.

[0019] The above-mentioned housing can hold the above-mentioned stator by interference fit.

[0020] According to the above configuration, the stator can be firmly fixed to the housing. In addition, although it is an example, the above configuration can be achieved by hot press fitting, shrink fitting, press fitting, etc.

[0021] According to another aspect of the present disclosure, a method for manufacturing a motor includes: expanding the inner circumferential surface of a housing radially outward; disposing the outer circumferential surface of a stator opposite to the expanded inner circumferential surface of the housing; and contracting the inner circumferential surface of the housing to bring the inner circumferential surface into contact with the outer circumferential surface of the stator. A plurality of groove portions that extend along the axial direction and are arranged along the circumferential direction are provided on the outer circumferential surface of the stator. At least one protrusion that abuts against the inner surface of any one of the plurality of groove portions is provided on the inner circumferential surface of the housing. When the stator and the housing are disposed opposite to each other, the housing and the stator are circumferentially positioned such that the protrusion and the groove portion are opposite to each other. When the housing and the stator are brought into contact with each other, the protrusion abuts against at least one first groove portion among the plurality of groove portions, but does not abut against a second groove portion among the plurality of groove portions.

[0022] According to the above configuration, the stress relaxation function can be exerted through a plurality of groove portions, and the positioning of the housing and the stator in the circumferential direction can be performed.

[0023] When the housing and the stator are brought into contact with each other, the housing and the stator can be relatively displaced in the circumferential direction by the force generated between the protruding portion and the inner surface of the first groove portion that are in contact with each other.

[0024] In a state where the outer peripheral surface of the stator and the expanded inner peripheral surface of the housing are opposed to each other, there is a case where the circumferential position of the stator with respect to the housing slightly deviates from the desired position. According to the above configuration, the stator can be moved to the desired position by the relative displacement of the housing and the stator in the circumferential direction.

[0025] When the housing and the stator are brought into contact with each other, at least a part of the protruding portion can be plastically deformed by coming into contact with the first groove portion.

[0026] According to the above configuration, since the contact area between the protruding portion and the first groove portion increases, the stator can be firmly fixed to the housing.

[0027] When the housing and the stator are brought into contact with each other, the first groove portion can be filled without a gap by the protruding portion.

[0028] According to the above configuration, since the contact area between the protruding portion and the first groove portion increases, the stator can be firmly fixed to the housing.

[0029] When the housing and the stator are brought into contact with each other, plastic deformation may not occur in the protruding portion.

[0030] According to the above configuration, compared with the structure in which plastic deformation occurs in the protruding portion, the contact area between the protruding portion and the inner surface of the first groove portion can be reduced. Therefore, the pressure acting on the stator can be further relaxed. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Hereinafter, with reference to the drawings, the features, advantages, and technical and industrial significance of the exemplary embodiments of the present invention will be described. In the drawings, the same reference numerals denote the same elements, wherein,

[0032] Figure 1 is a cross-sectional view in a direction perpendicular to the axial direction of the drive device 2 according to the first embodiment.

[0033] Figure 2 is a cross-sectional view in the axial direction of the drive device 2 according to the first embodiment.

[0034] Figure 3 is a cross-sectional view in a direction perpendicular to the axial direction in the manufacturing process of the motor 10 according to the first embodiment.

[0035] Figure 4 is an axial cross-sectional view in the manufacturing process of the motor 10 according to the first embodiment.

[0036] Figure 5 is an axial cross-sectional view in the manufacturing process of the motor 10 according to the first embodiment.

[0037] Figure 6 is an axial cross-sectional view of the drive device 202 according to the second embodiment.

[0038] Figure 7 is an axial cross-sectional view in the manufacturing process of the motor 210 according to the second embodiment.

[0039] Figure 8 is an axial cross-sectional view of the drive device 302 according to the third embodiment.

[0040] Figure 9 is an axial cross-sectional view in the manufacturing process of the motor 310 according to the third embodiment. Detailed Description of the Invention

[0041] First Embodiment

[0042] Refer to Figure 1 and Figure 2 to describe the drive device 2. The drive device 2 includes a motor 10 and is mounted on an electric vehicle or the like. Herein, in this specification, a cylindrical coordinate system composed of an axial direction D1, a radial direction D2, and a circumferential direction D3 is defined based on the rotation axis A of the motor 10. The axial direction D1 is a direction parallel to the rotation axis A, and its coordinate axis is defined on the rotation axis. The radial direction D2 is a direction perpendicular to the axial direction D1 and is defined by a coordinate axis with the rotation axis A as the origin. Moreover, the circumferential direction D3 is a direction perpendicular to both the axial direction D1 and the radial direction D2 and is defined by a coordinate axis that encircles the rotation axis A.

[0043] As Figure 1 shown, the motor 10 includes a housing 12, a shaft 14, a rotor 16, and a stator 18. The shaft 14, the rotor 16, and the stator 18 are accommodated in the housing 12. In addition, although not shown in the figure, the drive device 2 further includes a gear unit that is mechanically connected to the motor 10. The gear unit is disposed on one side of the axial direction D1 with respect to the motor 10. Herein, one side of the axial direction D1 is Figure 1 the right side.

[0044] The shaft 14 extends along the rotation axis A. The rotation axis A is the rotation center of the shaft 14. The shaft 14 is rotatably supported by the housing 12 by bearings. The rotor 16 is fixed to the shaft 14. The stator 18 is fixed to the housing 12 by hot press fitting. The stator 18 is made of a metal material such as iron or steel. As Figure 2As shown, a plurality of groove portions 22 extending along the axial direction D1 are provided on the outer peripheral surface 20 of the stator 18. When viewed along the axial direction D1, the plurality of groove portions 22 have a shape that bends along an arc. The plurality of groove portions 22 are arranged at equal intervals in the circumferential direction D3. In the present embodiment, eight groove portions 22 are provided on the outer peripheral surface 20. The eight groove portions 22 include four first groove portions 24 in which a first protrusion portion 40A described later exists inside, and four second groove portions 26 in which the first protrusion portion 40A does not exist inside. The first groove portions 24 and the second groove portions 26 are alternately arranged in the circumferential direction D3.

[0045] Figure 1 The housing 12 of is made of a metal material such as aluminum. The housing 12 is made of a material having a lower hardness than the stator 18. The housing 12 includes a central housing 30, a first cover 32, and a second cover 34. The central housing 30 has a cylindrical shape. The central housing 30 extends along the axial direction D1. Both ends of the central housing 30 in the axial direction D1 are open. The first cover 32 is attached to one end of the central housing 30 in the axial direction D1. The second cover 34 is attached to the other end of the central housing 30 in the axial direction D1.

[0046] As Figure 2 shown, a plurality of axial flow paths 36 penetrating the central housing 30 along the axial direction D1 are formed in the central housing 30. The plurality of axial flow paths 36 extend along the axial direction D1. The plurality of axial flow paths 36 are arranged at equal intervals in the circumferential direction D3. A plurality of first protrusion portions 40A protruding inward in the radial direction D2 are provided on the inner peripheral surface 38 of the central housing 30. The plurality of first protrusion portions 40A extend along the axial direction D1. The plurality of first protrusion portions 40A are arranged at equal intervals in the circumferential direction D3. In the present embodiment, four first protrusion portions 40A are provided on the inner peripheral surface 38. The first protrusion portion 40A is disposed inside the first groove portion 24 of the stator 18. That is, the first protrusion portion 40A exists inside the first groove portion 24 of the stator 18. The first protrusion portion 40A abuts against the inner surface of the first groove portion 24. The first protrusion portion 40A has a gap with the first groove portion 24 and is in contact with each other. That is, a gap exists between the first protrusion portion 40A and the inner surface of the first groove portion 24. As Figure 1 shown, the first protrusion portion 40A has a tapered section 42 and a flat section 44. The tapered section 42 is a section in which the protruding height from the inner peripheral surface 38 gradually increases as it goes toward the one side in the axial direction D1. The protruding height is the length on the inner side in the radial direction D2. The flat section 44 is a section in which the protruding height is constant. The first protrusion portion 40A abuts against the inner surface of the first groove portion 24 in the flat section 44. As Figure 2 shown, when viewed along the axial direction D1, the first protrusion portion 40A in the tapered section 42 has a shape that bends along an arc. Further, when viewed along the axial direction D1, the first protrusion portion 40A in the flat section 44 has a shape in which the shape that bends along an arc is crushed.

[0047] As Figure 1 shown, a plurality of first circumferential flow paths 50 are formed in the first cover 32. The plurality of first circumferential flow paths 50 are arranged along the circumferential direction D3. The first circumferential flow paths 50 connect two axial flow paths 36 adjacent in the circumferential direction D3. Although not shown, one of the plurality of first circumferential flow paths 50 connects a supply flow path for supplying refrigerant. In addition, one of the plurality of first circumferential flow paths 50 connects a discharge flow path for discharging refrigerant to the outside.

[0048] A plurality of second circumferential flow paths 52 are formed in the second cover 34. The plurality of second circumferential flow paths 52 are arranged along the circumferential direction D3. The second circumferential flow paths 52 connect two axial flow paths 36 adjacent in the circumferential direction D3. A refrigerant system for the refrigerant to flow for cooling the motor 10 is formed by the plurality of first circumferential flow paths 50, the plurality of axial flow paths 36, and the plurality of second circumferential flow paths 52.

[0049] Manufacturing method of the motor 10

[0050] Refer to Figures 1 to 4 , and the manufacturing method of the motor 10 will be described. In this embodiment, the step of fixing the stator 18 to the central housing 30 of the housing 12 is characteristic. Therefore, only the step of fixing the stator 18 to the housing 12 will be described.

[0051] First, as Figure 3 shown, by heating the central housing 30 of the housing 12, the inner peripheral surface 38 of the central housing 30 is temporarily expanded outward in the radial direction D2. Among them, in the state before the stator 18 is fixed to the central housing 30, a second protrusion 40B having only a tapered section 46 and no flat section is provided on the inner peripheral surface 38. The tapered section 46 is a section where the protruding height from the inner peripheral surface 38 gradually increases as it goes toward the side in the axial direction D1. In addition, as Figure 4 shown, the second protrusion 40B has a shape that bends along an arc. The radius of curvature of the second protrusion 40B is smaller than the radius of curvature of the groove portion 22 of the stator 18. The inner peripheral surface 38 only needs to be expanded so that the end portion on the inner side in the radial direction D2 of the tapered section 46 of the second protrusion 40B coincides with the innermost part of the groove portion 22 of the stator 18.

[0052] Next, the central housing 30 and the stator 18 are positioned in the circumferential direction D3 such that the second protruding portion 40B of the inner circumferential surface 38 of the central housing 30 faces the first groove portion 24 of the stator 18. Next, by moving the stator 18 in the axial direction D1, the outer circumferential surface 20 of the stator 18 is disposed to face the expanded inner circumferential surface 38 of the central housing 30. As a result, the second protruding portion 40B of the inner circumferential surface 38 of the central housing 30 faces the first groove portion 24 of the stator 18. Among them, in Figure 4 , the position of the central portion in the circumferential direction D3 of the second protruding portion 40B is aligned with the position of the central portion in the circumferential direction D3 of the first groove portion 24.

[0053] Next, by cooling the central housing 30, the inner circumferential surface 38 of the central housing 30 contracts inward in the radial direction D2. As described above, the hardness of the central housing 30 is lower than that of the stator 18. Therefore, by the contraction of the inner circumferential surface 38, the second protruding portion 40B of the central housing 30 that abuts against the inner surface of the first groove portion 24 of the stator 18 is crushed. That is, the second protruding portion 40B plastically deforms and changes into Figure 2 the first protruding portion 40A. In addition, by the contraction of the inner circumferential surface 38, a part of the inner circumferential surface 38 abuts against the outer circumferential surface 20 of the stator 18. In this part, stress due to thermal contraction acts on the stator 18. As a result, the stator 18 is fixed to the central housing 30. That is, the central housing 30 holds the stator 18 by shrinkage fit.

[0054] In the above, as Figure 4 shown, when the outer circumferential surface 20 of the stator 18 is disposed to face the expanded inner circumferential surface 38 of the central housing 30, the position of the central portion in the circumferential direction D3 of the second protruding portion 40B is aligned with the position of the central portion in the circumferential direction D3 of the first groove portion 24. However, as Figure 5 shown, there is a case where the position of the central portion in the circumferential direction D3 of the second protruding portion 40B is not aligned with the position of the central portion in the circumferential direction D3 of the first groove portion 24. In such a situation, if the central housing 30 is cooled, the central housing 30 and the stator 18 are displaced relative to each other in the circumferential direction D3 due to the force generated between the inner surfaces of the mutually abutting second protruding portion 40B and the first groove portion 24. Specifically, the central housing 30 and the stator 18 are displaced relative to each other such that the position of the central portion in the circumferential direction D3 of the first groove portion 24 is aligned with the position of the central portion in the circumferential direction D3 of the second protruding portion 40B. In addition, similarly to the above, the second protruding portion 40B plastically deforms, and stress due to thermal contraction acts on the stator 18. As a result, the central housing 30 and the stator 18 are aligned, and the stator 18 is fixed to the central housing 30.

[0055] As described above, as Figure 1, Figure 2 As shown in Figure 2 , the motor 10 includes: a housing 12 having a cylindrical inner peripheral surface 38; and a stator 18 having an outer peripheral surface 20 that abuts against the inner peripheral surface 38 from the inner side in the radial direction D2. A plurality of groove portions 22 are provided on the outer peripheral surface 20 of the stator 18, extending along the axial direction D1 and arranged in the circumferential direction D3. At least one first protrusion 40A (an example of a "protrusion") that abuts against any inner surface of the plurality of groove portions 22 is provided on the inner peripheral surface 38 of the housing 12. The plurality of groove portions 22 include at least one first groove portion 24 where the first protrusion 40A exists and a second groove portion 26 where the first protrusion 40A does not exist.

[0056] In the above configuration, the outer peripheral surface 20 of the stator 18 abuts against the inner peripheral surface 38 of the housing 12 from the inner side in the radial direction D2, and the housing 12 holds the stator 18 by the pressure acting on the stator 18 from the housing 12. In such a configuration, if the pressure acting on the stator 18 is too large, the magnetic characteristics of the stator 18 may unexpectedly change. Regarding this point, in the above configuration, a plurality of groove portions 22 are formed on the outer peripheral surface 20 of the stator 18, whereby the pressure acting on the stator 18 can be moderately relieved. In addition, the plurality of groove portions 22 include a first groove portion 24 where the first protrusion 40A provided on the housing 12 exists and a second groove portion 26 where such a protrusion does not exist. According to such a configuration, when manufacturing the motor 10, the stress-relieving function can be exerted by the plurality of groove portions 22, and the positioning of the housing 12 and the stator 18 can be easily performed in the circumferential direction D3.

[0057] In addition, as Figure 2 shown, the first protrusion 40A and the first groove portion 24 have a gap and are in contact with each other.

[0058] According to the above configuration, in the first groove portion 24 that abuts against the first protrusion 40A of the housing 12, the pressure acting on the stator 18 can also be intentionally relieved.

[0059] In addition, as Figure 2 shown, a plurality of first protrusions 40A are provided on the inner peripheral surface 38 of the housing 12. The plurality of first protrusions 40A are arranged at equal intervals in the circumferential direction.

[0060] According to the above configuration, the centering accuracy can be improved between the stator 18 and the housing 12.

[0061] In addition, as Figure 2 shown, the plurality of groove portions 22 are arranged at equal intervals in the circumferential direction.

[0062] According to the above configuration, the pressure acting on the stator 18 can be averaged.

[0063] In addition, as Figure 1As shown, the first protrusion 40A extends along the axial direction D1.

[0064] According to the above configuration, it is possible to improve the centering accuracy between the stator 18 and the housing 12.

[0065] In addition, as Figure 1 shown, the first protrusion 40A has a tapered section 42 where the protruding height from the inner peripheral surface 38 gradually increases toward one side in the axial direction D1.

[0066] According to the above configuration, when assembling the housing 12 and the stator 18, it is easy to arrange the first protrusion 40A of the housing 12 relative to the first groove portion 24 of the stator 18.

[0067] In addition, the housing 12 holds the stator 18 by thermo - press fitting (an example of "interference fit").

[0068] According to the above configuration, the stator 18 can be firmly fixed relative to the housing 12.

[0069] In addition, as Figures 1 to 4 shown, the manufacturing method of the motor 10 includes a process of expanding the inner peripheral surface 38 of the housing 12 outward in the radial direction D2, a process of arranging the outer peripheral surface 20 of the stator 18 opposite to the expanded inner peripheral surface 38 of the housing 12, and a process of contracting the inner peripheral surface 38 of the housing 12 to bring the inner peripheral surface 38 into contact with the outer peripheral surface 20 of the stator 18.

[0070] According to the above configuration, the stress - relaxation function can be exerted by the plurality of groove portions 22, and the positioning of the housing 12 and the stator 18 in the circumferential direction can be achieved.

[0071] In addition, in the process of bringing the inner peripheral surface 38 into contact with the outer peripheral surface 20 of the stator 18, due to the force generated between the second protrusion 40B (an example of a "protrusion") and the inner surface of the first groove portion 24, the housing 12 and the stator 18 are relatively displaced in the circumferential direction.

[0072] In a state where the outer peripheral surface 20 of the stator 18 is arranged opposite to the expanded inner peripheral surface 38 of the housing 12, there is a case where the position of the stator 18 in the circumferential direction D3 relative to the housing 12 slightly deviates from the desired position. According to the above configuration, by the relative displacement of the housing 12 and the stator 18 in the circumferential direction D3, the position of the stator 18 in the circumferential direction D3 can be moved to the desired position.

[0073] In addition, in the process of bringing the inner peripheral surface 38 into contact with the outer peripheral surface 20 of the stator 18, at least a part of the second protrusion 40B is plastically deformed due to contact with the first groove portion 24.

[0074] According to the above configuration, since the contact area between the second protruding portion 40B and the first groove portion 24 increases, the stator 18 can be firmly fixed to the housing 12. In addition, as described above, in the configuration in which the stator 18 is cooled by the refrigerant system of the housing 12, the cooling performance can be improved.

[0075] Second Embodiment

[0076] Refer to Figure 6 , the drive device 202 of the second embodiment will be described. For the drive device 202 of this embodiment, the configuration of the central housing 230 of the motor 210 is different from that of the central housing 30 of the motor 10 of the first embodiment. Among them, the same reference numerals are given to the configurations common to the embodiments, and the description thereof is omitted.

[0077] A plurality of first protruding portions 240A protruding inward in the radial direction D2 are provided on the inner peripheral surface 238 of the central housing 230. The plurality of first protruding portions 240A extend along the axial direction D1. The plurality of first protruding portions 240A are arranged at equal intervals in the circumferential direction D3. In this embodiment, four first protruding portions 240A are provided on the inner peripheral surface 238. The first protruding portion 240A is disposed inside the first groove portion 24 of the stator 18. The first protruding portion 240A abuts against the inner surface of the first groove portion 24. The first protruding portion 240A has a gap with the first groove portion 24 and is in contact therewith. That is, there is a gap between the first protruding portion 240A and the inner surface of the first groove portion 24. The first protruding portion 240A abuts against the inner surface of the first groove portion 24 between one end and the other end of the stator 18 in the axial direction D1. When viewed along the axial direction D1, the first protruding portion 240A has a certain shape that bends along an arc.

[0078] Manufacturing Method of Motor 10

[0079] Refer to Figure 6 , Figure 7 , the manufacturing method of the motor 210 of the second embodiment will be described. Among them, the steps of temporarily expanding the inner peripheral surface 238 of the central housing 230 outward in the radial direction D2 and the step of disposing the outer peripheral surface 20 of the stator 18 opposite to the expanded inner peripheral surface 238 are the same as those of the first embodiment, so the description of these steps is omitted.

[0080] After the outer peripheral surface 20 of the stator 18 is disposed opposite to the expanded inner peripheral surface 238 of the central housing 230, the central housing 230 is cooled to contract the inner peripheral surface 238 of the central housing 230 inward in the radial direction D2. In Figure 6In this case, the position of the central portion in the circumferential direction D3 of the second protrusion 240B of the central housing 230 does not coincide with the position of the central portion in the circumferential direction D3 of the first groove portion 24 of the stator 18. In this situation, due to the force generated between the inner surfaces of the mutually abutting second protrusion 240B and the first groove portion 24, the central housing 230 and the stator 18 are relatively displaced in the circumferential direction D3. Additionally, as the inner circumferential surface 238 of the central housing 230 contracts, a part of the inner circumferential surface 238 abuts against the outer circumferential surface 20 of the stator 18. In the present embodiment, the inner circumferential surface 238 is contracted in such a manner that no plastic deformation occurs in the second protrusion 240B of the central housing 230. As a result, as Figure 6 shown, the innermost part in the radial direction D2 of the second protrusion 240B of the central housing 230 abuts against the innermost part in the radial direction D2 of the first groove portion 24 of the stator 18. Therefore, the shape of the second protrusion 240B (refer to Figure 7 ) before the stator 18 is fixed to the central housing 230 is the same as the shape of the first protrusion 240A after the stator 18 is fixed to the central housing 230.

[0081] As described above, in the process of bringing the inner circumferential surface 238 of the central housing 230 into contact with the outer circumferential surface 20 of the stator 18, no plastic deformation occurs in the second protrusion 240B (an example of a "protrusion").

[0082] According to the above configuration, compared with a configuration in which plastic deformation occurs in the second protrusion 240B, the contact area between the second protrusion 240B and the inner circumferential surface 238 can be reduced. Therefore, the pressure acting on the stator 18 can be further alleviated.

[0083] (Third Embodiment)

[0084] Refer to Figure 8 to describe the drive device 302 of the third embodiment. For the drive device 302 of the present embodiment, the configuration of the central housing 330 of the motor 310 is different from that of the central housing 30 of the motor 10 of the first embodiment.

[0085] A plurality of first protrusions 340A protruding inward in the radial direction D2 are provided on the inner circumferential surface 338 of the central housing 330. In Figure 8In [the figure], for easy understanding, a plurality of first protrusions 340A are shown in gray. The plurality of first protrusions 340A extend along the axial direction D1. The plurality of first protrusions 340A are arranged at equal intervals in the circumferential direction D3. In the present embodiment, four first protrusions 340A are provided on the inner circumferential surface 338. The first protrusions 340A are filled inside the first slot portion 24 of the stator 18. That is, the first protrusions 340A are in contact with the first slot portion 24 without any gap therebetween. Therefore, when viewed along the axial direction D1, the first protrusions 340A have a shape corresponding to the first slot portion 24.

[0086] Manufacturing method of the motor 10

[0087] Refer to Figure 8 、 Figure 9 The manufacturing method of the motor 310 according to the third embodiment will be described. Among them, similar to the second embodiment, the description of the process of temporarily expanding the inner circumferential surface 338 of the central housing 330 outward in the radial direction D2 and the process of disposing the outer circumferential surface 20 of the stator 18 opposite to the expanded inner circumferential surface 338 are omitted.

[0088] As Figure 9 shown, after the outer circumferential surface 20 of the stator 18 and the expanded inner circumferential surface 338 of the central housing 330 are disposed opposite to each other, the central housing 330 is cooled to contract the inner circumferential surface 338 of the central housing 330 inward in the radial direction D2. In Figure 9 , the position of the central portion in the circumferential direction D3 of the second protrusion 340B of the central housing 330 does not coincide with the position of the central portion in the circumferential direction D3 of the first slot portion 24 of the stator 18. In this case, due to the force generated between the second protrusion 340B and the inner surface of the first slot portion 24 that are in contact with each other, the central housing 330 and the stator 18 are relatively displaced in the circumferential direction D3. In addition, due to the contraction of the inner circumferential surface 338 of the central housing 330, a part of the inner circumferential surface 338 comes into contact with the outer circumferential surface 20 of the stator 18. And, in response to the contact with the inner surface of the first slot portion 24 of the stator 18, the second protrusion 340B of the central housing 330 is crushed. That is, the second protrusion 340B undergoes plastic deformation. In the present embodiment, the inner circumferential surface 338 of the central housing 330 is contracted in such a way that the second protrusion 340B of the central housing 330 is filled into the first slot portion 24 of the stator 18. As a result, as Figure 8 shown, the first protrusions 340A are filled inside the first slot portion 24 of the stator 18.

[0089] As described above, as Figure 8 shown, the first protrusions 340A (an example of "protrusions") and the first slot portion 24 are in contact with each other without any gap therebetween.

[0090] According to the above configuration, compared with the configuration in which there is a gap between the first protrusion 340A and the first groove portion 24 and they are in contact with each other, the contact area between the first protrusion 340A and the first groove portion 24 can be increased. Therefore, the stator 18 can be firmly fixed to the housing 12 through the first groove portion 24. In addition, in the configuration in which the stator 18 is cooled by the refrigerant system of the housing 12, if the contact area between the housing 12 and the stator 18 increases, the heat transfer performance is improved. That is, the cooling performance can be improved. According to the above configuration, since the contact area between the first protrusion 340A and the first groove portion 24 increases compared with the configuration in which there is a gap between the first protrusion 340A and the first groove portion 24 and they are in contact with each other, the contact area between the housing 12 and the stator 18 also increases. Therefore, the cooling performance can be improved.

[0091] In addition, in the process of bringing the inner circumferential surface 338 into contact with the outer circumferential surface 20 of the stator 18, the first protrusion 340A deformed plastically fills the first groove portion 24 without a gap.

[0092] According to the above configuration, since the contact area between the second protrusion 340B and the first groove portion 24 increases, the stator 18 can be firmly fixed to the housing 12. In addition, as described above, in the configuration in which the stator 18 is cooled by the refrigerant system of the housing 12, the cooling performance can be improved.

[0093] As described above, specific examples of the technology disclosed in this specification have been described in detail, but these are merely examples and do not limit the technical solution. The technology described in the technical solution includes technologies that are various deformations and changes of the above-described specific examples.

[0094] First modification

[0095] In each of the above embodiments, one first protrusion 40A, 240A, 340A is present in one first groove portion 24. A plurality of first protrusions 40A, 240A, 340A may also be present in one first groove portion 24.

[0096] Second modification

[0097] The plurality of first protrusions 40A, 240A, 340A may be arranged at unequal intervals in the circumferential direction D3.

[0098] Third modification

[0099] The plurality of groove portions 22 may also be arranged at unequal intervals in the circumferential direction D3.

[0100] Fourth modification

[0101] The first protrusions 40A, 240A, 340A may not extend along the axial direction D1. That is, on the axial direction D1, the first protrusions 40A, 240A, 340A may be provided in a part within the first groove portion 24. Although it is an example, the first protrusions 40A, 240A, 340A may be provided only at the central portion on the axial direction D1 of the first groove portion 24.

[0102] Fifth modification

[0103] The shapes of the protrusions present in each of the first groove portions 24 may be different. For example, the cross-sectional shape of the protrusion present in each of the first groove portions 24 may also be triangular or the like. In addition, the shapes of the respective first groove portions 24 may also be different corresponding to the shapes of the protrusions.

[0104] In addition, the technical elements described in this specification or the drawings exhibit technical utility individually or in various combinations, and are not limited to the combinations described in the technical solutions. In addition, the technologies exemplified in this specification or the drawings can achieve multiple purposes simultaneously, and achieving one of the purposes itself has technical utility.

Claims

1. A motor, characterized in that, The motor includes: a housing having a cylindrical inner peripheral surface; and a stator having an outer peripheral surface that abuts against the inner peripheral surface from the inner side in the radial direction, wherein, on the outer peripheral surface of the stator, a plurality of groove portions are provided that extend along the axial direction and are arranged along the circumferential direction, on the inner peripheral surface of the housing, at least one protrusion is provided that abuts against the inner surface of any one of the plurality of groove portions, the plurality of groove portions include at least one first groove portion against which the protrusion abuts and a second groove portion against which the protrusion does not abut.

2. The motor according to claim 1, wherein the protrusion and the first groove portion are in partial contact with each other.

3. The motor according to claim 1, wherein the protrusion and the inner surface of the first groove portion are in overall contact with each other.

4. The motor according to claim 1, wherein a plurality of the protrusions are provided on the inner peripheral surface of the housing, the plurality of protrusions are arranged at equal intervals in the circumferential direction.

5. The motor according to claim 4, wherein the plurality of groove portions are arranged at equal intervals in the circumferential direction.

6. The motor according to claim 1, wherein the protrusion extends along the axial direction.

7. The motor according to claim 6, wherein the protrusion has a tapered section in which the protruding height from the inner peripheral surface gradually increases toward one side in the axial direction.

8. The motor according to claim 1, wherein the housing holds the stator by interference fit.

9. A manufacturing method of a motor, characterized in that, The method for manufacturing the motor includes: expanding the inner peripheral surface of the housing radially outward; oppositely disposing the outer peripheral surface of the stator on the expanded inner peripheral surface of the housing; and contracting the inner peripheral surface of the housing so that the inner peripheral surface abuts against the outer peripheral surface of the stator, wherein, on the outer peripheral surface of the stator, a plurality of groove portions are provided that extend along the axial direction and are arranged along the circumferential direction, on the inner peripheral surface of the housing, at least one protrusion is provided that abuts against the inner surface of any one of the plurality of groove portions, when the stator and the housing are oppositely disposed, the housing and the stator are positioned in the circumferential direction such that the protrusion faces one of the plurality of groove portions, when the housing and the stator are brought into contact with each other, the protrusion abuts against at least one first groove portion among the plurality of groove portions, but does not abut against the second groove portion among the plurality of groove portions.

10. The method for manufacturing the motor according to claim 9, wherein when the housing and the stator are brought into contact with each other, a force generated between the abutting protrusion and the inner surface of the first groove portion causes relative displacement between the housing and the stator in the circumferential direction.

11. The method for manufacturing the motor according to claim 9, wherein when the housing and the stator are brought into contact with each other, at least a part of the protrusion is plastically deformed by abutting against the first groove portion.

12. The method for manufacturing the motor according to claim 11, wherein when the housing and the stator are brought into contact with each other, the first groove portion is filled without clearance by the protrusion.

13. The manufacturing method of the motor according to claim 9, characterized in that when the housing is brought into contact with the stator, no plastic deformation occurs in the protruding portion.

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