Housing, stator, electric motor, and fastened member

Abstract

A housing according to the present disclosure is provided to a stator of an electric motor, and comprises: a fastened portion having formed therein an opening into which a shaft portion of a screw member is inserted; and a protruding portion that protrudes from the fastened portion and bites into a bearing surface of the screw member when the screw member is fastened.

Description

Housing, stator, motor and fastened member

[0001] The present disclosure relates to a housing, a stator, an electric motor, and a fastened member.

[0002] Japanese Patent Laid-Open Publication No. 60-096147 discloses an AC electric machine. According to Japanese Patent Laid-Open Publication No. 60-096147, the AC electric machine includes a pair of side housings. The pair of side housings are fastened together with screws.

[0003] There is a need for better techniques for fastening members using threaded members.

[0004] A first aspect of the present disclosure is a housing provided in a stator of an electric motor, comprising: a fastening portion having an opening formed therein into which the shank of a screw member is inserted; and a convex portion protruding from the fastening portion and biting into the seating surface of the screw member when the screw member is fastened.

[0005] A second aspect of the present disclosure is a stator comprising a housing according to the first aspect of the present disclosure.

[0006] A third aspect of the present disclosure is an electric motor including the stator according to the second aspect of the present disclosure.

[0007] A fourth aspect of the present disclosure is a fastened member that is fastened using a screw member, and that includes a fastened portion having an opening into which the shank of the screw member is inserted, and a convex portion that protrudes from the fastened portion and bites into the seating surface of the screw member when the screw member is fastened.

[0008] FIG. 1A is a schematic diagram showing a portion of an electric motor according to one embodiment. FIG. 1B is a partial enlarged view of FIG. 1A. FIG. 2A is a plan view of a housing. FIG. 2B is a partial enlarged view of FIG. 2A. FIG. 3A is a perspective view showing one of a plurality of fastened portions provided on a fastened member. FIG. 3B is a partial enlarged view of FIG. 3A. FIG. 3C is a cross-sectional view of the convex portion shown in FIG. 3A. FIG. 4 is a perspective view of the convex portion according to Modification 1. FIG. 5 is a perspective view of the convex portion according to Modification 2. FIG. 6 is a perspective view of the convex portion according to Modification 3.

[0009] The prior art, including that disclosed in JP 60-096147 A, has at least the following problem. That is, providing a screw with a special structure to prevent loosening increases the unit price of the screw. As a result, the unit price of a product that includes the screw and the fastened components that are fastened using the screw increases.

[0010] Based on the above preliminary explanation, one embodiment will be described below.

[0011] (One embodiment) Fig. 1A is a schematic diagram showing a portion of an electric motor 10 according to one embodiment. Fig. 1A shows a stator 12 provided in the electric motor 10. Fig. 1B is a partially enlarged view of Fig. 1A. Fig. 1B shows a portion surrounded by a box IB in Fig. 1A. Fig. 2A is a plan view of a housing 18. Fig. 2A shows a first housing 181 as viewed in the axial direction of the electric motor 10. Fig. 2B is a partially enlarged view of Fig. 2A. Fig. 2B shows a portion surrounded by a box IIB in Fig. 2A.

[0012] As shown in FIG. 1A, the stator 12 includes a stator core 14 , a coil portion 16 , and a plurality of housings 18 .

[0013] The stator core 14 is a cylindrical (annular) member provided in the electric motor 10. The stator core 14 includes, for example, a plurality of electromagnetic steel plates laminated along the axial direction DS of the electric motor 10. A rotor and a shaft of the electric motor 10 are disposed inside the stator core 14. The extending direction of the shaft coincides with the axial direction DS of the electric motor 10. Note that illustrations of the electromagnetic steel plates, rotor, and shaft are omitted.

[0014] The stator core 14 also has two ends (axial end portions 14t) in the axial direction DS and a side portion 14s facing in a direction perpendicular to the axial direction DS. The two axial end portions 14t include a first axial end portion 14t1 that is one of the axial end portions 14t in the axial direction DS and a second axial end portion 14t2 that is the other axial end portion 14t in the axial direction DS. The side portion 14s faces radially outward from the shaft (not shown) described above.

[0015] The coil portion 16 is provided in an annular shape so as to surround the rotor. The coil portion 16 is inserted into, for example, a slot formed in the stator core 14. The coil portion 16 is formed of a conducting wire.

[0016] Each of the plurality of housings 18 is a member that covers at least a portion of the stator core 14. By covering at least a portion of the stator core 14, the plurality of housings 18 further cover the coil portion 16 provided in the stator core 14.

[0017] As shown in FIG. 1A , at least one of the multiple housings 18 may selectively cover the axial end 14t of the stator core 14 or the side portion 14s of the stator core 14. In other words, at least one of the multiple housings 18 may cover the axial end 14t without covering the side portion 14s. In this case, the multiple housings 18 may include a first housing 181 and a second housing 182. The first housing 181 is a housing 18 that covers the first axial end 14t1 of the stator core 14 while exposing the side portion 14s. The second housing 182 is a housing 18 that covers the second axial end 14t2 of the stator core 14 while exposing the side portion 14s. Although not shown in FIGS. 1A to 2B , one of the first housing 181 and the second housing 182 may have an opening through which the above-mentioned shaft (not shown) is inserted.

[0018] The first housing 181 and the second housing 182 are made of a conductive material, such as, but not limited to, aluminum (Al).

[0019] The first housing 181 and the second housing 182 are fastened together by electrically conductive screw members 20. The screw members 20 may be made of, for example, iron (Fe), but are not limited to this. The first housing 181 and the second housing 182 may be fastened together by a plurality of screw members 20.

[0020] The first housing 181 is a fastened member 22 that is fastened using the screw member 20. The first housing 181, which is the fastened member 22, has a fastened portion 24 and a protrusion 26, which will be described below.

[0021] The fastened portion 24 is a portion of the fastened member 22 where an opening 28 is formed. The opening 28 is an open end of a hole 22h formed in the fastened member 22 (first housing 181).

[0022] The hole 22h is a through-hole that penetrates the first housing 181 along the axial direction DS. The through-hole is a through-hole. That is, the diameter of the hole 22h is large enough to allow the shank 20b of the screw member 20 to be inserted therethrough. The shape of the hole 22h (opening 28) in plan view is not limited to a circular shape.

[0023] The screw member 20 is inserted through the first housing 181 via an opening 28 formed in the fastened portion 24. The screw member 20 inserted through the first housing 181 threads into a threaded hole (female thread) 182h formed in the second housing 182. This fastens the first housing 181 and the second housing 182 together. Furthermore, the screw member 20 inserted through the first housing 181 threads into the threaded hole 182h, thereby fixing the first housing 181 and the second housing 182 to the stator core 14. The threaded hole 182h formed in the second housing 182 may have a bottom 182hb ( FIG. 1A ), but is not limited thereto. Furthermore, the male thread (thread) that threads into the threaded hole 182h is formed at least in a portion of the shaft portion 20b that can be inserted into the threaded hole 182h (the tip portion of the shaft portion 20b) ( FIG. 1A ). The male thread may be formed over the entire shaft portion 20b.

[0024] The protrusion 26 is a portion that protrudes from the fastened portion 24. The fastened member 22 (first housing 181) may have multiple protrusions 26. However, in the following description, in order to avoid redundant explanation, attention will be focused on one of the multiple protrusions 26 unless otherwise specified.

[0025] The protrusion 26 may be integrally molded with the fastened portion 24 (the fastened member 22). In this case, the protrusion 26 may be formed from the same material (aluminum, etc.) as the fastened portion 24 (the fastened member 22).

[0026] The protruding direction DP of the convex portion 26 intersects (is perpendicular to) the in-plane direction, which is a direction parallel to the abutment surface 24s of the fastened portion 24. In other words, the protruding direction DP is along the out-of-plane direction, which is a direction perpendicular to the abutment surface 24s. The abutment surface 24s is the surface of the fastened portion 24 that abuts against the seat surface 20s of the screw member 20. The opening 28 described above is formed in the abutment surface 24s. Note that the out-of-plane direction in this embodiment coincides with the axial direction DS of the electric motor 10.

[0027] The protrusion 26 is located within a range of the abutment surface 24s that can abut against the seat surface 20s of the screw member 20 when the screw member 20 is inserted into the opening 28. Therefore, the protrusion 26 can bite into the seat surface 20s of the screw member 20 when the screw member 20 is fastened. Note that the more specific position of the protrusion 26 can be determined as appropriate based on, for example, the design of the screw member 20.

[0028] The amount of protrusion of the convex portion 26 gradually increases along the rotation direction DR of the screw member 20. The rotation direction DR is the direction in which the screw member 20 rotates when the screw member 20 is fastened. In other words, the screw member 20 is screwed into the screw hole 182h by being rotated in the rotation direction DR.

[0029] Fig. 3A is a perspective view showing one of the multiple fastened portions 24 provided on the fastened member 22. Fig. 3B is a partial enlarged view of Fig. 3A. One of the multiple protrusions 26 shown in Fig. 3A is shown in Fig. 3B. Fig. 3C is a cross-sectional view of the protrusion 26 shown in Fig. 3A. A cross-section of the protrusion 26 along the rotation direction DR is shown in Fig. 3C. This cross-section is taken in the direction IIIC of Fig. 3A.

[0030] The protrusion 26 has multiple surfaces 26s. For example, as shown in FIG. 3B , the protrusion 26 has four surfaces 26s. The number of surfaces 26s is determined depending on the shape of the protrusion 26. Each of the multiple surfaces 26s is inclined with respect to the out-of-plane direction (axial direction DS) described above. It is preferable that the multiple surfaces 26s of the protrusion 26 form an obtuse angle with the abutment surface 24s. That is, it is preferable that each of the multiple angles θ shown in FIGS. 3B and 3C is an obtuse angle (θ>90°). The angle θ is the angle formed between the surface 26s of the protrusion 26 and the abutment surface 24s.

[0031] The multiple surfaces 26s include a first surface 26s1 and a second surface 26s2. The first surface 26s1 is a surface 26s that extends from an end 26t1 of the convex portion 26 in the direction opposite to the rotational direction DR to a protruding end 26p of the convex portion 26. The first surface 26s1 extends along the in-plane direction of the abutment surface 24s. In contrast, the second surface 26s2 is a surface 26s that extends from the protruding end 26p of the convex portion 26 to an end 26t2 of the convex portion 26 in the rotational direction DR. The second surface 26s2 is located in the rotational direction DR with respect to the first surface 26s1 and extends along the out-of-plane direction.

[0032] A first angle θ1 and a second angle θ2 are shown in Figure 3C. The first angle θ1 is preferably greater than the second angle θ2 (θ1 > θ2). The first angle θ1 is the angle θ between the first surface 26s1 and the abutment surface 24s. In contrast, the second angle θ2 is the angle θ between the second surface 26s2 and the abutment surface 24s.

[0033] The shape (planar shape) of the protrusion 26 in a plan view (axial view) along the protrusion direction DP may be triangular (see also FIG. 2B ). More specifically, this planar shape is the shape of the first surface 26s1 in a planar view. In this case, the planar shape is preferably a triangle whose width gradually increases along the rotation direction DR. In other words, it is preferable that one vertex PA of the three vertices P included in the triangular shape coincides with the end 26t1 of the protrusion 26 in the opposite direction (described above), and that the remaining two vertices P (vertex PB, vertex PC) are located in the rotation direction DR relative to vertex PA.

[0034] 3C , the cross section of the protrusion 26 taken along the direction of rotation DR has a triangular shape. In this case, three imaginary line segments connecting vertices PA, PD, and PE included in the triangular shape can be identified as three sides (three sides) S that define the shape of the cross section of the protrusion 26.

[0035] It is preferable that the length of at least one side (first side) S of these three sides S is different from the lengths of the remaining two sides (second sides) S. That is, it is preferable that the cross-sectional shape is a scalene triangle or an isosceles triangle. It is more preferable that the cross-sectional shape is a scalene triangle. Note that the vertex PD shown in FIG. 3C may be included in the protruding end 26p of the convex portion 26. In that case, the vertex PE may be included in the end portion 26t2 described above.

[0036] The first angle θ1 and the second angle θ2 described above each correspond to the size of an exterior angle of the triangle defined by the three sides S. More specifically, the first angle θ1 corresponds to the size of the exterior angle tangent to the side S connecting the vertices PD and PE, among the three sides defining the shape of the cross section described above. In contrast, the second angle θ2 corresponds to the size of the exterior angle tangent to the side S connecting the vertices PA and PD, among the three sides defining the shape of the cross section described above.

[0037] 3C further shows the maximum protrusion amount H of the protrusion 26 provided on the fastened member 22, which is the housing 18 of the stator 12. The maximum protrusion amount H is preferably determined in advance based on the amount of thermal expansion dH. In other words, the position in the protruding direction DP of the protruding end 26p of the protrusion 26 provided on the fastened member 22, which is the housing 18 of the stator 12, is preferably determined in advance based on the amount of thermal expansion dH.

[0038] The amount of thermal expansion dH is the amount of expansion of the convex portion 26 in the protruding direction DP when the rated current is supplied to the stator 12 (electric motor 10). In other words, the housing 18 may thermally expand in response to the supply of current to the electric motor 10. Based on this, when the fastened member 22 is the housing 18, it is preferable that the maximum amount of protrusion H of the convex portion 26 when no current is flowing through the electric motor 10 be determined based on the amount of thermal expansion dH of the convex portion 26 when the rated current is supplied to the electric motor 10.

[0039] More specifically, the maximum protrusion amount H of the protrusion 26 when no current is flowing through the electric motor 10 is preferably greater than the thermal expansion amount dH of the protrusion 26 when the rated current is supplied to the electric motor 10 (dH<H). The thermal expansion amount dH is the increase in the dimension of the protrusion 26 in the protrusion direction DP. The thermal expansion amount dH is the product of the difference between the first linear expansion coefficient α1 and the second linear expansion coefficient α2, the maximum protrusion amount H, and the temperature rise amount dT (see also equation (1)). The first linear expansion coefficient α1 is the linear expansion coefficient of the fastened member 22 (first housing 181). The second linear expansion coefficient α2 is the linear expansion coefficient of the screw member 20. The temperature rise amount dT is the temperature rise amount of the fastened member 22 when the rated current is supplied to the electric motor 10. It is preferable that the thermal expansion amount dH and the maximum protrusion amount H shown in equation (1) satisfy the above-mentioned relationship (dH<H).

[0040]

[0041] Based on formula (1), the material of the fastened member 22 and the material of the screw member 20 may be determined so that the following formula (2) is satisfied. This allows the above-mentioned preferable relationship (dH<H) between the amount of thermal expansion dH and the maximum protrusion amount H to be established.

[0042]

[0043] The fastened member 22 having the above-described configuration can achieve the following effects, for example.

[0044] The fastened member 22 has a protrusion 26. The protrusion 26 bites into the seat surface 20s of the screw member 20 when the screw member 20 is fastened. The protrusion 26 biting into the seat surface 20s prevents the screw member 20 from loosening. In this way, there is no need to provide the screw member 20 with a special structure to prevent loosening. As a result, an increase in the unit price of the screw member 20 is suppressed.

[0045] Moreover, the protrusion amount of the convex portion 26 gradually increases along the rotation direction DR of the screw member 20. In other words, the convex portion 26 has a gradient along the rotation direction DR. As a result, the convex portion 26 is unlikely to hinder the screw member 20 from rotating in the rotation direction DR, but is likely to hinder the screw member 20 from rotating in the opposite direction to the rotation direction DR. In other words, the convex portion 26 suppresses the screw member 20 from loosening without hindering the screw member 20 from being fastened.

[0046] The protrusion 26 has multiple surfaces 26s. Each of the multiple surfaces 26s may be inclined with respect to the out-of-plane direction of the abutment surface 24s of the fastened portion 24. In this case, it is preferable that the multiple surfaces 26s form an obtuse angle with the abutment surface 24s. When the protrusion 26 has such a shape, the fastened member 22 having the protrusion 26 can be easily manufactured by die casting. That is, the shape of the protrusion 26 according to this embodiment does not hinder the opening and closing of a mold along the protrusion direction DP. Therefore, the fastened member 22 can be easily manufactured by die casting using a mold. In this case, the manufacturing process of a conventional fastened member (such as a stator housing) by die casting can be reused, except for, for example, changing the mold. As a result, the increase in manufacturing costs of the fastened member 22 compared to conventional fastened members can be suppressed.

[0047] The multiple surfaces 26s include the first surface 26s1 and the second surface 26s2 described above. The first surface 26s1 extends along the in-plane direction of the abutting surface 24s. In contrast, the second surface 26s2 extends along the out-of-plane direction of the abutting surface 24s. In other words, the second surface 26s2 is steeper than the first surface 26s1. As a result, the protrusions 26 are less likely to hinder the screw member 20 from rotating in the rotation direction DR, but are more likely to hinder the screw member 20 from rotating in the direction opposite to the rotation direction DR. In other words, the protrusions 26 suppress loosening of the screw member 20 without hindering the screw member 20 from being fastened.

[0048] The planar shape of the convex portion 26 (first surface 26s1) in a plan view may be triangular. This planar shape is preferably a triangle that gradually widens along the rotation direction DR. This makes it difficult for the convex portion 26 to hinder the screw member 20 from rotating in the rotation direction DR, but it also makes it easier for the convex portion 26 to hinder the screw member 20 from rotating in the opposite direction to the rotation direction DR. In other words, the convex portion 26 prevents the screw member 20 from loosening without hindering the screw member 20 from being fastened.

[0049] The cross-sectional shape of the protrusion 26 along the rotation direction DR may be triangular. Preferably, the triangular shape is a triangular shape other than an equilateral triangle. More preferably, the lengths of the three sides S defining the triangular shape are different from each other. This makes it easier for the second surface 26s2 to be formed steeper than the first surface 26s1. Therefore, the protrusion 26 can easily prevent the screw member 20 from loosening without interfering with the fastening of the screw member 20.

[0050] As described above, the fastened member 22 is, for example, the housing 18 (first housing 181) that covers at least a portion of the stator core 14. By preventing the screw member 20 from loosening, the first housing 181 and the screw member 20 (seat surface 20s) are kept in good contact with each other. This allows the first housing 181 to be in good electrical continuity (ground continuity) with the second housing 182, into which the screw member 20 is threaded, via the screw member 20.

[0051] The maximum protrusion amount H of the protrusion 26 when no current is supplied to the electric motor 10 is preferably greater than the thermal expansion amount dH of the protrusion 26 when rated current is supplied to the electric motor 10. This allows the protrusion 26 to be properly engaged with the seating surface 20s of the screw member 20 when the fastened member 22 is the housing 18 of the stator 12. That is, the linear expansion coefficient (first linear expansion coefficient) of the housing 18 may be greater than the linear expansion coefficient (second linear expansion coefficient) of the screw member 20. For example, the linear expansion coefficient of the housing 18 made of aluminum is greater than the linear expansion coefficient of the screw member 20 made of iron. That is, the thermal expansion amount dH of the housing 18 when power is applied to the electric motor 10 is greater than the thermal expansion amount of the screw member 20 in this case. As a result, the seating surface 20s of the screw member 20 engages relatively strongly with the abutment surface 24s, forming a recessed (concave) shape on the abutment surface 24s. The housing 18, which has been thermally expanded, contracts as the temperature of the electric motor 10 decreases. However, by providing the aforementioned recessed shape to the abutment surface 24s, a gap may be formed between the abutment surface 24s and the seating surface 20s. The size of the gap is determined according to the amount of contraction (thermal expansion amount dH) of the housing 18. If the protrusion amount of the convex portion 26 is not sufficiently large compared to the gap, the convex portion 26 will not be able to properly dig into the seating surface 20s. In this regard, according to the present embodiment, the maximum protrusion amount H of the convex portion 26 when no current is supplied to the electric motor 10 is determined taking into account the thermal expansion amount dH of the convex portion 26. As a result, even if the aforementioned gap is formed, the protrusion amount of the convex portion 26 is sufficiently ensured, allowing the convex portion 26 to dig into the seating surface 20s.

[0052] One embodiment may be modified as follows. In the following modifications, descriptions that overlap with the embodiment will be omitted as appropriate. In addition, in the drawings used in the following modifications, the same reference numerals are used for the same components as those described in the embodiment.

[0053] (Modification 1) FIG. 4 is a perspective view of the convex portion 26 (convex portion 261) according to Modification 1. As shown in FIG.

[0054] As shown in Fig. 4, the shape of the convex portion 261 in plan view is annular. The annular convex portion 261 is arranged so as to surround the opening 28. The inner diameter of the convex portion 261 in plan view is larger than the diameter of the opening 28, but is not limited to this. For example, the inner diameter of the convex portion 261 in plan view may be equal to the diameter of the opening 28. Note that although the number of convex portion 261 shown in Fig. 4 is singular, the number is not limited to this.

[0055] The protrusion 261 has a step 30 facing the rotation direction DR. The step 30 is located between the portion of the protrusion 261 where the amount of protrusion is smallest (end 26t1) and the portion of the protrusion 261 where the amount of protrusion is largest (protruding end 26p). The amount of protrusion of the protrusion 261 gradually increases from the position of the step 30 (predetermined position) along the rotation direction DR of the screw member 20.

[0056] According to this modification, similarly to the first embodiment, when the screw member 20 is fastened, the convex portion 261 bites into the seating surface 20s (see FIG. 1B ) of the screw member 20. The convex portion 261 biting into the seating surface 20s prevents the screw member 20 from loosening. Moreover, the convex portion 261 can prevent the screw member 20 from loosening without interfering with the fastening of the screw member 20.

[0057] The multiple surfaces 26s of the protrusion 261, including the surface of the step 30, are preferably inclined with respect to the out-of-plane direction (the protruding direction DP) of the abutment surface 24s, so that the fastened member 22 including the protrusion 261 can be easily manufactured by die casting (see also one embodiment).

[0058] Furthermore, the surface 26s of the step 30 faces the rotational direction DR. Therefore, the surface 26s is a second surface 26s2 (see also one embodiment). The multiple surfaces 26s of the protrusion 261 also include a first surface 26s1, which is a surface 26s located in the opposite direction of the rotational direction DR from the second surface 26s2. The first surface 26s1 extends along the in-plane direction of the abutment surface 24s. This allows the protrusion 261 to prevent the screw member 20 from loosening without interfering with the fastening of the screw member 20 (see also one embodiment).

[0059] (Modification 2) FIG. 5 is a perspective view of the protrusion 26 (protrusion 262) according to Modification 2. As shown in FIG.

[0060] 5, the shape of the convex portion 262 in a plan view is an arc. The arc-shaped convex portion 262 curves along the rotation direction DR of the screw member 20.

[0061] 5, a plurality of protrusions 262 may protrude from the fastened portion 24 (see also one embodiment). The plurality of protrusions 262 are arranged so as to surround the opening 28 along the rotation direction DR. The protrusion amount of each of the plurality of protrusions 262 gradually increases along the rotation direction DR of the screw member 20.

[0062] According to this modification, similarly to the first embodiment, when the screw member 20 is fastened, the convex portion 262 bites into the seating surface 20s (see FIG. 1B ) of the screw member 20. The convex portion 262 biting into the seating surface 20s prevents the screw member 20 from loosening. Moreover, the convex portion 262 can prevent the screw member 20 from loosening without interfering with the fastening of the screw member 20.

[0063] The multiple surfaces 26s of the protrusion 262 are preferably inclined with respect to the out-of-plane direction of the abutment surface 24s, so that the fastened member 22 including the protrusion 262 can be easily manufactured by die casting (see also one embodiment).

[0064] Furthermore, the multiple surfaces 26s of the protrusion 262 include a first surface 26s1 and a second surface 26s2 (see also the embodiment). As a result, the protrusion 262 can suppress loosening of the screw member 20 without interfering with fastening of the screw member 20.

[0065] (Modification 3) FIG. 6 is a perspective view of the protrusion 26 (protrusion 263) according to Modification 3. As shown in FIG.

[0066] 6, the shape of the convex portion 263 in a plan view is a spiral shape extending along the rotation direction DR of the screw member 20. The spiral-shaped convex portion 263 is disposed so as to surround the opening 28. Note that, although the number of convex portion 263 shown in FIG. 6 is singular, the number is not limited to this.

[0067] The protrusion amount of the convex portion 263 gradually increases along the longitudinal direction of the convex portion 263. The protrusion amount of the spiral-shaped convex portion 263 gradually increases from the outside to the inside of the spiral ( FIG. 6 ), but is not limited to this. The protrusion amount of the spiral-shaped convex portion 263 may also gradually increase from the inside to the outside of the spiral.

[0068] According to this modification, similarly to the first embodiment, when the screw member 20 is fastened, the convex portion 263 bites into the seating surface 20s of the screw member 20. The convex portion 263 biting into the seating surface 20s prevents the screw member 20 from loosening. Moreover, the convex portion 263 can prevent the screw member 20 from loosening without interfering with the fastening of the screw member 20.

[0069] The multiple surfaces 26s of the protrusion 263 are preferably inclined with respect to the out-of-plane direction of the contact surface 24s, so that the fastened member 22 including the protrusion 263 can be easily manufactured by die casting (see also one embodiment).

[0070] Furthermore, the multiple surfaces 26s of the protrusion 263 include a first surface 26s1 and a second surface 26s2 (see also the embodiment). As a result, the protrusion 263 can suppress loosening of the screw member 20 without interfering with fastening of the screw member 20.

[0071] (Modification 4) The hole 22h may be formed with a female screw. In this case, the screw member 20 can be threaded into the female screw.

[0072] (Modification 5) The fastened member 22 is not limited to the housing 18 of the stator 12. The configuration of the fastened member 22 can be applied to various members that can be fastened by the screw member 20.

[0073] (Combination of Multiple Modifications) The multiple modifications described above may be combined as appropriate within a range that does not cause inconsistency.

[0074] According to the above embodiment and modified example, loosening of the screw member 20 is suppressed. Moreover, there is no need to provide the screw member 20 with a special structure for preventing loosening.

[0075] The following additional notes are further disclosed regarding the above embodiment.

[0076] (Appendix 1) The housing (181) according to the present disclosure is a housing provided in the stator (12) of the electric motor (10), and includes a fastening portion (24) having an opening (28) formed therein into which the shank (20b) of the screw member (20) is inserted, and a convex portion (26) that protrudes from the fastening portion and bites into the seat surface (20s) of the screw member when the screw member is fastened.

[0077] (Supplementary Note 2) The housing according to Supplementary Note 1 may be configured such that the protruding amount of the convex portion gradually increases along the rotation direction (DR) of the screw member when the screw member is fastened.

[0078] (Appendix 3) The housing may be the one described in Appendix 2, wherein the convex portion has a plurality of surfaces (26s), and each of the plurality of surfaces is inclined with respect to the out-of-plane direction of the abutment surface (24s), which is the surface of the fastened portion that abuts the seat surface.

[0079] (Supplementary Note 4) In the housing according to Supplementary Note 3, the plurality of surfaces may form an obtuse angle with the abutment surface.

[0080] (Appendix 5) The housing may be the one described in Appendix 3, wherein the plurality of surfaces include a first surface (26s1) extending along the in-plane direction of the abutment surface, and a second surface (26s2) positioned in the rotational direction relative to the first surface and extending along the out-of-plane direction.

[0081] (Supplementary Note 6) The housing according to any one of Supplementary Notes 2 to 5 may be such that the shape of the convex portion in plan view is triangular.

[0082] (Supplementary Note 7) The housing according to Supplementary Note 6 may be configured such that a cross section of the convex portion along the rotation direction has a shape of a scalene triangle or an isosceles triangle.

[0083] (Supplementary Note 8) The housing according to any one of Supplementary Notes 2 to 5 may be such that the shape of the convex portion in plan view is annular, arc-shaped, or spiral-shaped.

[0084] (Appendix 9) The housing according to any one of Appendices 1 to 8 may be such that the stator is provided with a stator core (14), and the housing covers an axial end portion (14t) of the stator core in the axial direction (DS) of the motor without covering a side portion (14s) of the stator core in a direction intersecting the axial direction of the motor.

[0085] (Appendix 10) The housing may be the one described in any one of Appendices 1 to 9, wherein the maximum protrusion amount (H) of the convex portion when no current is supplied to the electric motor is greater than the amount of thermal expansion (dH) of the convex portion when a rated current is supplied to the electric motor and the temperature of the electric motor rises.

[0086] (Appendix 11) The housing according to Appendix 10 may be one in which the amount of thermal expansion is the product of the difference between a first linear expansion coefficient (α1) that is the linear expansion coefficient of the housing and a second linear expansion coefficient (α2) that is the linear expansion coefficient of the screw member, the maximum protrusion amount, and the amount of temperature rise (dT) of the housing when the rated current is supplied to the electric motor.

[0087] (Supplementary Note 12) A stator (12) according to the present disclosure is a stator including the housing according to any one of Supplementary Notes 1 to 11.

[0088] (Supplementary Note 13) An electric motor (10) according to the present disclosure is an electric motor including the stator according to Supplementary Note 12.

[0089] (Appendix 14) The fastened member (22) according to the present disclosure is a fastened member that is fastened using a screw member (20), and includes a fastened portion (24) formed with an opening (28) into which the shank (20b) of the screw member is inserted, and a convex portion (26) that protrudes from the fastened portion and bites into the seat surface (20s) of the screw member when the screw member is fastened.

[0090] Although the present disclosure has been described in detail, the present disclosure is not limited to the individual embodiments described above. Various additions, substitutions, modifications, partial deletions, etc. are possible in these embodiments without departing from the gist of the present disclosure or the spirit of the present disclosure derived from the content of the claims and their equivalents. These embodiments can also be implemented in combination. For example, in the above-described embodiments, the order of each operation and the order of each process are shown as examples and are not limited to these. The same applies when numerical values ​​or mathematical expressions are used in the description of the above-described embodiments.

[0091] DESCRIPTION OF SYMBOLS 10...Electric motor 12...Stator 14...Stator core 14s...Side portion 14t...Axial end portion 20...Thread member 20b...Shaft portion 20s...Seat surface 22...Fastened member 24...Fastened portion 24s...Abutment surface 26...Convex portion 26s...Surface 26s1...First surface 26s2...Second surface 28...Opening 181...First housing (housing) dH...Thermal expansion amount dT...Temperature rise amount H...Maximum protrusion amount S...Side (3 sides) α1...First linear expansion coefficient α2...Second linear expansion coefficient

Claims

1. A housing provided in a stator of an electric motor, comprising: a fastening portion having an opening formed therein into which the shank of a screw member is inserted; and a protrusion protruding from the fastening portion and biting into the seating surface of the screw member when the screw member is fastened.

2. A housing according to claim 1, wherein the amount of protrusion of the convex portion gradually increases along the direction of rotation of the screw member when the screw member is fastened.

3. A housing as set forth in claim 2, wherein the convex portion has a plurality of surfaces, each of which is inclined with respect to the out-of-plane direction of the contact surface, which is the surface of the fastened portion that contacts the seat surface.

4. A housing according to claim 3, wherein said plurality of surfaces form an obtuse angle with said abutment surface.

5. A housing according to claim 3, wherein the plurality of surfaces include a first surface extending along the in-plane direction of the abutment surface, and a second surface positioned in the rotational direction relative to the first surface and extending along the out-of-plane direction.

6. A housing according to any one of claims 2 to 5, wherein the shape of the convex portion in plan view is triangular.

7. A housing according to claim 6, wherein the cross section of said convex portion along said direction of rotation has a shape of a scalene triangle or an isosceles triangle.

8. A housing according to any one of claims 2 to 5, wherein the shape of the convex portion in plan view is annular, arc-shaped or spiral-shaped.

9. A housing according to any one of claims 1 to 8, wherein the stator is provided with a stator core, and the housing covers the axial end portion, which is the end portion of the stator core in the axial direction of the motor, without covering the side portion of the stator core in the direction intersecting the axial direction of the motor.

10. A housing as claimed in any one of claims 1 to 9, wherein the maximum amount of protrusion of the convex portion when no current is supplied to the motor is greater than the amount of thermal expansion of the convex portion when a rated current is supplied to the motor and the temperature of the motor rises.

11. A housing as claimed in claim 10, wherein the amount of thermal expansion is the product of the difference between a first linear expansion coefficient which is the linear expansion coefficient of the housing and a second linear expansion coefficient which is the linear expansion coefficient of the screw member, the maximum protrusion amount and the amount of temperature rise of the housing when the rated current is supplied to the electric motor.

12. A stator comprising a housing according to any one of claims 1 to 11.

13. An electric motor comprising the stator according to claim 12.

14. A fastened member that is fastened using a screw member, comprising: a fastened portion having an opening formed therein into which the shank of the screw member is inserted; and a convex portion that protrudes from the fastened portion and bites into the seating surface of the screw member when the screw member is fastened.

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