Motor

Abstract

To provide a motor that reduces iron loss while maintaining heat dissipation from a stator to a housing.SOLUTION: The motor includes a rotor that rotates around a rotation axis, a stator including an annular portion that extends in a circumferential direction around the rotation axis and surrounds the rotor and a protruding portion 132 that protrudes outward from an outer peripheral surface of the annular portion at a part in the circumferential direction, and a housing 140 that is in contact with the annular portion on an inner peripheral surface extending in the circumferential direction and in which the protruding portion is fitted into a recessed portion 144 provided at a part in the circumferential direction to fix the stator.SELECTED DRAWING: Figure 7

Description

[Technical Field]

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

[0002] Patent Document 1 proposes a technology that can reduce the decrease in efficiency of a rotating machine while employing a structure that holds the stator by the clamping force of the housing. In Patent Document 1, the outer circumferential surface of the stator is formed with a contact surface that contacts the inner circumferential surface of the housing, and a non-contact surface that forms a gap between the outer circumferential surface of the housing and the contact surface.

[0003] Patent Document 2 proposes a technology for reducing iron loss inside the core due to surface pressure from a retaining ring. In Patent Document 2, slits are provided through the outer peripheral edge of the back yoke of the split core, leaving both circumferential ends of the back yoke. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2006-191702 [Patent Document 2] Japanese Patent Application Laid-Open No. 2011-254624 Summary of the Invention [Problem to be solved by the invention]

[0005] If gaps or slits are formed, they will prevent heat dissipation from the stator to the housing. Also, if the tightening force of the housing increases, compressive stress on the laminated core (magnetic part) will lead to increased iron loss. Therefore, an object of the present disclosure is to reduce iron loss while maintaining heat dissipation properties. [Means for solving the problem]

[0006] One aspect of the motor according to the present disclosure comprises a rotor that rotates around a rotation axis, a stator that includes an annular portion that extends in a circumferential direction around the rotation axis and surrounds the rotor, and a protrusion that protrudes outward from the outer circumferential surface of the annular portion at a portion in the circumferential direction, and a housing that contacts the annular portion at an inner circumferential surface extending in the circumferential direction and in which the protrusion fits into a recess provided at a portion in the circumferential direction, thereby fixing the stator. [Effects of the Invention]

[0007] According to the present disclosure, it is possible to reduce iron loss while maintaining heat dissipation properties. [Brief explanation of the drawings]

[0008] [Figure 1] FIG. 1 is a diagram showing a schematic diagram of the basic configuration of a motor. [Figure 2] FIG. 2 is a diagram showing a state in which the stator is fixed to the housing. [Figure 3] FIG. 3 is a view showing the housing. [Figure 4] FIG. 4 is a diagram showing the stator. [Figure 5] FIG. 5 is a diagram showing a state in which the stator is inserted into the housing. [Figure 6] FIG. 6 is an enlarged view showing the fitting portion where the first protrusion fits. [Figure 7] FIG. 7 is a diagram showing a state in which the first protrusion is fitted into the fitting portion. [Figure 8] FIG. 8 is an enlarged view showing the fitting portion where the second protrusion fits. [Figure 9] FIG. 9 shows a second protrusion following the groove. [Figure 10] FIG. 10 is a diagram showing a state in which the second protrusion is fitted into the fitting portion. [Figure 11] FIG. 11 is a diagram showing a modified example of the stator. [Figure 12] FIG. 12 is a diagram showing a state in which a stator is fixed to a housing in the second embodiment. [Figure 13]FIG. 13 is a view showing a housing in the second embodiment. [Figure 14] FIG. 14 is a partially enlarged view of a housing in the second embodiment. [Figure 15] FIG. 15 is a diagram showing a stator according to the second embodiment. [Figure 16] FIG. 16 is a diagram showing a state in which a stator is inserted into a housing in the second embodiment. [Figure 17] FIG. 17 is a diagram showing a state in which the protrusion is fitted into the groove in the second embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0009] Hereinafter, embodiments of the motor of the present disclosure will be described in detail with reference to the accompanying drawings. However, to avoid unnecessary redundancy in the following description and to facilitate understanding by those skilled in the art, more detailed description than necessary may be omitted. For example, detailed description of already well-known matters or redundant description of substantially identical configurations may be omitted. Furthermore, elements shown in earlier-described figures may be appropriately referenced in the description of later figures.

[0010] First Embodiment FIG. 1 is a diagram showing a schematic diagram of the basic configuration of a motor. The motor 100 includes a rotating shaft 110, a rotor 120, a stator 130, and a housing 140. The rotating shaft 110 is rotatably supported in the housing 140 by a bearing 150.

[0011] The rotating shaft 110 is the output shaft of the motor 100 and rotates with a driving force corresponding to the power supplied to the motor 100 . The rotor 120 is fixed to the rotary shaft 110 and rotates around the rotary shaft 110 . The stator 130 is fixed to the housing 140. The stator 130 rotates the rotor 120 by forming a magnetic field using power supplied to the motor 100.

[0012] The housing 140 supports the entire motor 100 . Fixing the stator 130 to the housing 140 requires sufficient strength and sufficient heat dissipation from the stator 130 to the housing 140. However, if the fixing force causes distortion in the stator 130, iron loss may cause a decrease in the performance of the motor 100. For this reason, this embodiment uses a fixing structure that maintains heat dissipation and reduces iron loss.

[0013] 2 to 4 are diagrams showing the housing 140 and the stator 130, with FIG. 2 showing the state in which the stator 130 is fixed to the housing 140, FIG. 3 showing the housing 140, and FIG. 4 showing the stator 130. Housing 140 is a cylindrical member having an outer peripheral surface 141 and an inner peripheral surface 142. Housing 140 has a bottom 143 on one side of the cylinder, and stator 130 is inserted into housing 140 from an opening 148 on the opposite side from bottom 143 and fixed therein.

[0014] In this specification, "comprises" means to comprise something in some form, whether it is an independent object or a part of an object, unless the context clearly indicates otherwise. In contrast, in this specification, "has" generally means to have something as part of an object.

[0015] The housing 140 has, on its inner circumferential surface 142, a plurality of grooves 144 extending along the axial direction along which the rotary shaft 110 extends. The grooves 144 correspond to an example of recesses provided in a portion of the inner circumferential surface 142 in the circumferential direction. In this embodiment, the housing 140 has, for example, six grooves 144, evenly arranged along the circumferential direction of the inner circumferential surface 142. Each groove 144 has, in a portion of the axial direction, mating positions 145, 146 that are deeper than the inner circumferential surface of the groove 144. The mating positions 145, 146 are part of the groove 144. Each groove 144 has the mating positions 145, 146 at multiple positions separated in the axial direction. In this embodiment, for example, the mating positions 145, 146 are provided on the opening 148 side and the bottom 143 side of the groove 144, respectively. Furthermore, the housing 140 has a pin 147 on the bottom 143 that protrudes toward the opening 148 in a direction along the rotation axis 110 .

[0016] Stator 130 includes an annular portion 131, protrusions 132 and 133, and teeth 134. Stator 130 is formed, for example, by stacking a plurality of magnetic steel plates in a direction along rotating shaft 110, and windings (not shown) are wound around teeth 134. When a current is passed through the windings, a magnetic field is formed mainly at the tips of teeth 134.

[0017] The annular portion 131 is an annular structural portion having an inner peripheral surface 135 and an outer peripheral surface 136. The annular portion 131 extends in a circumferential direction around the rotary shaft 110 and surrounds the rotor 120. The tooth portion 134 protrudes from the inner peripheral surface 135 of the annular portion 131 toward the rotor 120. A portion of the protrusions 132, 133 in the circumferential direction protrudes outward from the outer circumferential surface 136 of the annular portion 131. The protrusions 132, 133 have a hook-like shape bent in the circumferential direction along the outer circumferential surface 136 of the annular portion 131, and are elastically or plastically deformed. Note that the shape of the protrusions 132, 133 is not limited to a hook shape, and any shape that allows elastic or plastic deformation may be used.

[0018] In this embodiment, the protrusions 132, 133 are provided in equal numbers as first protrusions 132 and second protrusions 133, and the first protrusions 132 and second protrusions 133 are aligned in the axial direction along which the rotation shaft 110 extends. The first protrusions 132 are located on one side of the outer circumferential surface 136 of the annular portion 131 in the axial direction (upper side in FIG. 4). The second protrusions 133 are located on the other side of the outer circumferential surface 136 of the annular portion 131 in the axial direction (lower side in FIG. 4).

[0019] The stator 130 has a first protrusion 132 and a second protrusion 133 at positions corresponding to fitting positions 145, 146 provided in a groove 144 of the housing 140. The first protrusion 132 and the second protrusion 133 fit into the corresponding fitting positions 145, 146.

[0020] FIG. 5 is a diagram showing a state in which the stator 130 is inserted into the housing 140. As shown in FIG. As described above, the stator 130 is inserted into the housing 140 from the opening 148 side toward the bottom 143 side. When the stator 130 is inserted, the protrusions 132 and 133 of the stator 130 follow the groove 144 of the housing 140 toward the bottom 143 side.

[0021] By inserting the stator 130 into the housing 140, the outer peripheral surface 136 of the annular portion 131 of the stator 130 comes into contact with the inner peripheral surface 142 of the housing 140, thereby achieving sufficient heat dissipation. Furthermore, by inserting the stator 130 into the housing 140, the first protrusion 132 fits into a fitting portion 145 on the opening 148 side, and the second protrusion 133 fits into a fitting portion 146 on the bottom 143 side. The fitting of the protrusions 132, 133 into the fitting portions 145, 146 fixes the stator 130 to the housing 140.

[0022] <Protruding part fitting structure> Fig. 6 is an enlarged view showing the fitting portion 145 into which the first protrusion 132 fits, and Fig. 7 is an enlarged view showing the state in which the first protrusion 132 is fitted into the fitting portion 145. Note that Fig. 7 is a partially perspective view to make it easier to understand the fitted state. As described above, the fitting portion 145 is deeper than the inner peripheral surface of the groove 144 , and the edge 145 a of the fitting portion 145 protrudes into the inside of the groove 144 .

[0023] When the stator 130 is inserted into the groove 144, the first protrusion 132 is pressed into the groove 144 by, for example, elastic deformation, and when the first protrusion 132 reaches the fitting portion 145, the hook-like shape expands due to restoration deformation caused by the elastic force and fits into the fitting portion 145. As a result, the first protrusion 132 catches on the edge 145a of the fitting portion 145, and the stator 130 is fixed to the housing 140.

[0024] The first protrusion 132 may be fitted into the fitting location 145 by plastic deformation. That is, when the first protrusion 132 that has entered the groove 144 reaches the fitting location 145, a pin-shaped jig or the like is pushed into the inside of the hook-shaped shape of the first protrusion 132 from the opening 148 side. As a result, the hook-shaped shape expands due to plastic deformation, and the first protrusion 132 fits into the fitting location 145.

[0025] Even when the first protrusion 132 is fitted into the fitting portion 145 by plastic deformation, the first protrusion 132 hangs on the edge 145 a of the fitting portion 145 , and the stator 130 is fixed to the housing 140 . Figure 8 is an enlarged view showing the mating location 146 into which the second protrusion 133 fits, Figure 9 is a view showing the second protrusion 133 following the groove 144, and Figure 10 is a view showing the state in which the second protrusion 133 is fitted into the mating location 146.

[0026] The mating portion 146 on the bottom 143 side is also deeper than the inner peripheral surface of the groove 144. An edge 146a of the mating portion 146 protrudes toward the inside of the housing 140. The bottom 143 is provided with a pin 147 that protrudes in the axial direction of the groove 144, and the pin 147 fits inside the groove 144 and the mating portion 146.

[0027] As the stator 130 is inserted into the housing 140, the second protrusion 133 follows the groove 144 and reaches the fitting portion 146. When the second protrusion 133 reaches the fitting portion 146, the pin 147 protruding in the axial direction is fitted into the inside of the hook-shaped portion of the second protrusion 133 by the force of inserting the stator 130. As a result, the hook-shaped portion of the second protrusion 133 is pushed open by the pin 147 and plastically deformed, and the second protrusion 133 fits into the fitting portion 146. When the second protrusion 133 fits into the fitting portion 146, the second protrusion 133 engages with an edge 146a of the fitting portion 146, and the stator 130 is fixed to the housing 140.

[0028] The second protrusion 133 may be pressed into the groove 144 by elastic deformation, and when it reaches the fitting portion 146, it may be fitted into the fitting portion 146 by restoration deformation due to elastic force. In this way, the first protrusion 132 and the second protrusion 133 fit into the fitting portions 145, 146, thereby fixing the stator 130 to the housing 140. In this case, distortion due to the fixing force is concentrated on the first protrusion 132 and the second protrusion 133, and the impact of distortion on the annular portion 131 and the teeth 134 of the stator 130 is small. Therefore, iron loss is suppressed, and the performance of the motor 100 is maintained. Furthermore, except for the portion where groove 144 is provided, outer peripheral surface 136 of annular portion 131 of stator 130 is in contact with inner peripheral surface 142 of housing 140 over a wide area. Therefore, heat dissipation from stator 130 to housing 140 is also high. Furthermore, since the protrusions 132 and 133 have a hook-like shape and fit into the fitting portions 145 and 146 by deformation as the hooks open, residual strain is concentrated in the protrusions 132 and 133, further suppressing iron loss.

[0029] It should be noted that so-called shrink fitting may be performed on housing 140. That is, housing 140 is heated and expanded before stator 130 is inserted, and then cooled after stator 130 is inserted, thereby tightening and fixing stator 130. However, since a sufficient fixing force is obtained by fitting first protrusion 132 and second protrusion 133 into fitting portions 145, 146, the fixing force by shrink fitting can be small, and iron loss due to the shrink fitting force is suppressed.

[0030] 4 and other figures, the first protruding portion 132 and the second protruding portion 133 are axially separated and provided only in a portion of the axial direction. Therefore, the influence of distortion in the first protruding portion 132 and the second protruding portion 133 is limited to only a portion, further suppressing iron loss and the like. Furthermore, the first protruding portion 132 and the second protruding portion 133 are provided at a location on the outer circumferential surface 136 of the annular portion 131 that corresponds to the back side of the tooth portion 134. In other words, the first protruding portion 132 and the second protruding portion 133 are provided at a position in the circumferential direction of the annular portion 131 where the tooth portion 134 is provided.

[0031] The back side of tooth portion 134 has higher rigidity than other portions, and the influence of distortion is further suppressed by providing protrusions 132 and 133 on the back side of tooth portion 134. In addition, the back side of tooth portion 134 is located away from the magnetic flux path that passes from tooth portion 134 through annular portion 131, so the influence of iron loss due to residual distortion is further suppressed.

[0032] <Modification> FIG. 11 is a diagram showing a modified example of the stator 130. In FIG. The stator 130 of the modified example includes a main body member 137 and a separate member 138. The main body member 137 has an annular portion 131 and teeth 134. The separate member 138 is adjacent to the main body member 137 in the axial direction of the rotating shaft 110, and the protruding portions 132 and 133 are provided on the separate member 138. The main body member 137 is formed using a magnetic material and generates a magnetic field, but the separate member 138 may be formed using a non-magnetic material such as copper. By providing the protruding portions 132 and 133 on the separate member 138, in the stator 130 of the modified example, residual strain caused by fixing the stator 130 is confined to the separate member 138, thereby suppressing the effect on the magnetic properties of the main body member 137. Furthermore, since the separate member 138 is non-magnetic, the effect of residual strain on the magnetic properties of the stator 130 is further suppressed.

[0033] Second Embodiment Next, a second embodiment of the motor will be described. The motor of the second embodiment is similar to the motor 100 of the first embodiment, except for the fixing structure of the housing and the stator. Therefore, the following description will focus on the differences from the first embodiment, and redundant description of elements similar to elements already described will be omitted.

[0034] Figures 12 to 15 are views showing the housing 240 and the stator 230 in the second embodiment. Figure 12 shows a state in which the stator 230 is fixed to the housing 240, Figure 13 shows the housing 240, Figure 14 shows a partially enlarged view of the housing 240, and Figure 15 shows the stator 230.

[0035] Similar to the first embodiment, the housing 240 of the second embodiment is a cylindrical member having an outer peripheral surface 141 and an inner peripheral surface 142. In the second embodiment, the housing 240 also has a bottom 143 on one side of the cylinder, and the stator 230 is inserted into the housing 240 from an opening 148 on the opposite side from the bottom 143. In the second embodiment, after insertion, the stator 230 is fixed to the housing 240 by rotating the stator 230 in the circumferential direction of the inner peripheral surface 142 of the housing 240.

[0036] The housing 240 of the second embodiment has a plurality of grooves 241 on the inner circumferential surface 142. The grooves 241 extend along the axial direction in which the rotating shaft 110 extends. The shape of the grooves 241 differs from that of the first embodiment. In this embodiment, the housing 240 has, for example, six grooves 241 evenly arranged along the circumferential direction of the inner circumferential surface 142. The cross-sectional shape of each groove 241 is uniform in the axial direction and is wide in the circumferential direction. For each groove 241, a portion of the groove 241 at one end on the opening 148 side is blocked by a protrusion 243, leaving only an opening large enough to allow the stator 230 to be inserted.

[0037] An axially extending wedge portion 242 is provided in each groove 241, and the wedge portion 242 has a shape that protrudes in the circumferential direction. The axial length of the wedge portion 242 is, for example, equal to the axial length of the outer circumferential surface 136 of the stator 230. Similar to the first embodiment, the stator 230 of the second embodiment includes an annular portion 131, a protruding portion 232, and a tooth portion 134. The protruding portion 232 in the second embodiment also protrudes outward from the outer circumferential surface 136 of the annular portion 131 and has a hook-like shape that curves in the circumferential direction along the outer circumferential surface 136 of the annular portion 131. However, in the second embodiment, the protruding portion 232 extends in the axial direction. The axial length of the protruding portion 232 is, for example, equal to the axial length of the outer circumferential surface 136 of the stator 230.

[0038] FIG. 16 is a diagram showing a state in which stator 230 is inserted into housing 240, and FIG. 17 is a diagram showing a state in which protrusion 232 is fitted into groove 241. As shown in FIG. Stator 230 is inserted into housing 240 with protrusions 232 passing through grooves 241 of housing 240. Then, stator 230 is rotated counterclockwise in FIG. 16 relative to housing 240 from the state shown in FIG. 16 to reach the state shown in FIG. 12.

[0039] 17 , wedge portion 242 protruding in the circumferential direction is fitted between the tip of the hook-shaped portion of protruding portion 232 of stator 230 and outer circumferential surface 136 of stator 230 as stator 230 rotates, thereby widening the hook-shaped portion. As a result, protruding portion 232 fits into groove 241 of housing 240, and stator 230 is fixed to housing 240.

[0040] 15, the protruding portion 232 extends in the axial direction, so that the protruding portion 232 fits tightly into the groove 241, and the stator 230 is firmly fixed to the housing 240. Also in the second embodiment, the protruding portion 232 is provided at a position on the outer circumferential surface 136 of the annular portion 131 that corresponds to the back side of the tooth portion 134. In other words, the protruding portion 232 is provided at a position in the circumferential direction of the annular portion 131 where the tooth portion 134 is provided.

[0041] The back surface of tooth portion 134 has higher rigidity than other portions, and the influence of distortion is further suppressed by providing protrusion 232 on the back surface of tooth portion 134. In addition, the back surface of tooth portion 134 is located away from the magnetic flux path that passes from tooth portion 134 through annular portion 131, so the influence of iron loss due to residual distortion is further suppressed.

[0042] The above-described embodiments should be considered to be illustrative in all respects and not restrictive. The scope of the present invention is defined by the claims, not by the above-described embodiments, and is intended to include all modifications within the meaning and scope of the claims. The present technology can be configured as follows.

[0043] (1) a rotor that rotates around a rotation axis; a stator including an annular portion extending in a circumferential direction around the rotary shaft and surrounding the rotor, and a protrusion protruding outward from an outer circumferential surface of the annular portion at a portion in the circumferential direction; a housing having an inner circumferential surface extending in the circumferential direction in contact with the outer circumferential surface of the annular portion, the housing having a recess provided in a part of the inner circumferential surface in the circumferential direction, the protrusion fitting into a recess to fix the stator; A motor comprising:

[0044] (2) The motor according to (1), wherein the protrusion of the stator has a hook-like shape, and the hook-like shape expands due to restoring deformation caused by elastic force or plastic deformation, thereby fitting into the recess of the housing.

[0045] (3) the recess of the housing is a groove extending along the axial direction in which the rotation shaft extends, and the groove has a portion in the axial direction that is deeper than an inner circumferential surface of the groove, The motor according to (2), wherein the protrusion fits into the deepened portion of the groove.

[0046] (4) The groove has the deepened portions at a plurality of positions spaced apart in the axial direction, The motor according to (3), wherein the stator has the protrusions at positions corresponding to the deepened portions.

[0047] (5) The motor according to any one of (2) to (4), wherein the housing further includes a pin that protrudes in the axial direction of the rotary shaft and fits into the hooks of the protruding portion to widen the hooks.

[0048] (6) The motor according to (2), wherein the housing further includes a wedge portion that protrudes in the circumferential direction and fits between the tip of the hook of the protrusion and the outer circumferential surface of the stator to widen the hook.

[0049] (7) The motor according to (6), wherein the protrusion of the stator and the wedge of the housing extend in the axial direction.

[0050] (8) The motor described in (1) above, wherein the stator further includes a tooth portion protruding from the annular portion toward the rotor, and the protrusion is provided at a position in the circumferential direction where the tooth portion is provided.

[0051] (9) The stator comprises a main body member that forms a magnetic field and a separate member that is adjacent to the main body member in the axial direction in which the rotation axis extends and in which the protrusion is provided. The motor described in (1) to (5) and (8). [Explanation of symbols]

[0052] 100: Motor 110: Rotation axis 120: Rotor 130: Stator 131: Circular section 132, 133:Protrusion 134: Tooth 135: Inner surface 136: Outer surface 137: Main body member 138: Separate parts 140: Housing 141: Outer surface 142: Inner peripheral surface 143: Bottom 144: Groove 145, 146: Mating points 147: Pin 148: Opening 230: Stator 232:Protrusion 240: Housing 241: Groove 242: Wedge part

Claims

1. a rotor that rotates around a rotation axis; a stator including an annular portion extending in a circumferential direction around the rotary shaft and surrounding the rotor, and a protrusion protruding outward from an outer circumferential surface of the annular portion at a portion in the circumferential direction; a housing having an inner circumferential surface extending in the circumferential direction in contact with the outer circumferential surface of the annular portion, the housing having a recess provided in a part of the inner circumferential surface in the circumferential direction, the protrusion fitting into a recess to fix the stator; A motor comprising:

2. The motor according to claim 1 , wherein the protrusion of the stator has a hook-like shape, and the hook-like shape expands due to restoring deformation caused by elastic force or plastic deformation, thereby fitting into the recess of the housing.

3. the recess of the housing is a groove extending along the axial direction in which the rotation shaft extends, and the groove has a portion in the axial direction that is deeper than an inner circumferential surface of the groove, The motor of claim 2 , wherein the protrusion fits into the deepened portion of the groove.

4. The groove has the deepened portions at a plurality of positions spaced apart in the axial direction, The motor according to claim 3 , wherein the stator includes the protrusions at positions corresponding to the deepened portions.

5. The motor according to claim 2 , wherein the housing further comprises a pin that protrudes in the axial direction of the rotary shaft and fits into the hooks of the protrusion to widen the hooks.

6. The motor according to claim 2 , wherein the housing further includes a wedge portion that protrudes in the circumferential direction and fits between the tip of the hook of the protrusion and the outer circumferential surface of the stator to widen the hook.

7. The motor of claim 6 , wherein the protrusion of the stator and the wedge of the housing extend in the axial direction.

8. The motor according to claim 1 , wherein the stator further comprises teeth protruding from the annular portion toward the rotor, the protruding portions being provided at positions in the circumferential direction where the teeth are provided.

9. 2. The motor according to claim 1, wherein the stator comprises a main body member that generates a magnetic field, and a separate member that is adjacent to the main body member in the axial direction along which the rotation shaft extends and on which the protrusion is provided.

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