Axial gap motor

Abstract

To provide an axial gap motor with excellent heat dissipation. [Solution] The axial gap motor comprises a planar rotor 120 with a rotating shaft 130 as its center of rotation, a stator 150 positioned opposite one side of the rotor 120, and a heat dissipation section 160 provided in contact with the stator 150. The stator 150 is provided with a plurality of recesses 151g, and the heat dissipation section 160 is provided with an annular heat dissipation section 161 and a plurality of convex heat conduction sections 162 that protrude radially inward from the annular heat dissipation section 161 in correspondence with the plurality of recesses 151g.

Description

Technical Field

[0001] The present invention relates to an axial gap motor, and particularly to an axial gap motor considering heat dissipation.

Background Art

[0002] In order to use the motor in an appropriate state, it is necessary to release the heat generated near the coil of the stator to the outside according to the load. Regarding the heat dissipation of the motor, various proposals are disclosed in Patent Documents 1 and 2 below.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0004] In a motor, the core and coil of the stator may be covered with resin for insulation. In this case, since the thermal conductivity of the resin is lower than that of metal, there is a problem that the heat dissipation performance deteriorates. Therefore, in Patent Document 1, a high thermal conductivity member is arranged between the coils as a heat dissipation path to improve the heat dissipation performance. However, a new problem occurs in that the occupancy rate of the coils decreases due to the heat dissipation path, and the output of the motor decreases. On the other hand, a method of arranging a heat pipe in the gap between the coil and the case as in Patent Document 2 has been proposed. This method arranges the heat pipe in the axial direction in a radial gap motor having a coil on the outer peripheral side. Therefore, it cannot be applied to the heat dissipation of a planar axial gap motor.

[0005] Therefore, there has been a strong demand for an axial gap motor with excellent heat dissipation that does not adversely affect the coil structure or other aspects through the arrangement of heat conductive materials.

[0006] This invention was made to solve the above-mentioned problems, and aims to provide an axial gap motor with excellent heat dissipation. [Means for solving the problem]

[0007] The axial gap motor according to this invention comprises a planar rotor with a rotation axis as its center of rotation, a stator positioned opposite one face of the rotor, and a heat dissipation section provided in contact with the stator. The stator is provided with a plurality of recesses, and the heat dissipation section is provided with an annular heat dissipation section and a plurality of convex heat conduction sections projecting radially inward from the annular heat dissipation section in correspondence with the plurality of recesses.

[0008] In the axial gap motor according to this invention, the stator is provided with a first yoke portion having a first outer diameter and a second yoke portion having a second outer diameter smaller than the first outer diameter and having a plurality of recesses, and the annular heat dissipation portion may have an inner diameter corresponding to the outer diameter of the second yoke portion and be provided on the outer circumference of the second yoke portion.

[0009] In the axial gap motor according to this invention, a bearing is further provided to rotatably hold the rotor with respect to the stator, wherein the inner ring portion of the bearing is fixed to the outer circumferential surface of the rotor, and the outer ring portion of the bearing is fixed to the inner circumferential surface of the first yoke portion.

[0010] In the axial gap motor according to this invention, the outer surface of the annular heat dissipation portion may have irregularities for heat dissipation.

[0011] In the axial gap motor according to this invention, a plurality of grooves are provided on the inner circumferential surface of the annular heat dissipation portion, and each of the plurality of convex heat conductors may be provided such that one end of each convex heat conductor portion is detachably inserted into the corresponding groove of the annular heat dissipation portion, and the portion that protrudes radially inward from the annular heat dissipation portion is in contact with the recess of the stator. [Effects of the Invention]

[0012] In the axial gap motor according to this invention, a heat dissipation section having a convex heat conduction section protruding inward from an annular heat dissipation section is attached to a stator having a recess that matches the convex heat conduction section. As a result, heat generated in the stator is transferred from the recess of the stator to the annular heat dissipation section via the convex heat conduction section and released to the outside from the surface of the annular heat dissipation section. Therefore, efficient heat dissipation can be achieved in the axial gap motor without affecting the structure of the coil. [Brief explanation of the drawing]

[0013] [Figure 1] This is an exploded perspective view showing the components of the axial gap motor according to Embodiment 1 in a disassembled state. [Figure 2] This is an exploded perspective view showing the components of the axial gap motor according to Embodiment 1 in a disassembled state. [Figure 3] This is a cross-sectional view showing a cross-section of an axial gap motor according to Embodiment 1. [Figure 4] This is a perspective view showing an axial gap motor according to Embodiment 1. [Modes for carrying out the invention]

[0014] The embodiments of the axial gap motor of the present invention will be described below with reference to the drawings. In each figure, the same parts are denoted by the same reference numerals. Embodiment 1. The structure of the axial gap motor 100 in Embodiment 1 will be explained using Figures 1 to 4. Figure 1 is an exploded perspective view showing the components of the axial gap motor 100 according to Embodiment 1 in an disassembled state. Figure 2 is an exploded perspective view showing the components of the axial gap motor 100 according to Embodiment 1 in an disassembled state. Figure 3 is a cross-sectional view showing a cross-section of the axial gap motor 100 according to Embodiment 1. Figure 4 is a perspective view showing the axial gap motor 100 according to Embodiment 1.

[0015] Figure 1 is an exploded perspective view showing the state as seen from the lid 110 side, and Figure 2 is an exploded perspective view showing the state as seen from the heat dissipation section 160 side. Figures 1 to 3(a) show the lid 110, Figures 1 to 3(b) show the rotor 120, the rotating shaft 130 and the bearing 140, Figures 1 to 3(c) show the stator 150, Figures 1 to 3(d) show the heat dissipation section 160, and Figures 3(e) and 4 show the entire axial gap motor 100.

[0016] The axial gap motor 100 mainly comprises a cover 110, a rotor 120, a rotating shaft 130, a bearing 140, a stator 150, and a heat dissipation section 160. The cover 110, rotor 120, stator 150, and heat dissipation section 160 are stacked in the axial direction. Here, the direction along the axis of the rotating shaft 130, which is located at the rotation center of the rotor 120, is defined as the axial direction, the direction along the radius of the rotor 120, etc., is defined as the radial direction, and the direction along the rotation direction of the rotor 120 is defined as the circumferential direction.

[0017] The cover portion 110 is provided so as to face one side of the rotor 120. Together with the stator 150, the cover portion 110 constitutes the housing of the axial gap motor 100. The cover portion 110 is composed of a flat portion 110a, an outer cylindrical portion 110b, and a central hole portion 110h. The flat portion 110a is configured to be parallel to the disc-shaped rotor 120. The outer cylindrical portion 110b is provided radially outward, i.e., on the outer circumference, of the flat portion 110a. The central hole portion 110h is configured so that the rotation of the rotating shaft 130 can be extracted to the outside.

[0018] The rotor 120 is configured as a perforated disk-shaped body having a central hole for fixing the rotating shaft 130, and is disposed in the space provided between the lid portion 110 and the stator 150 so as to be rotatable about the rotating shaft 130. The rotor 120 includes a magnet holding portion 121a, a magnet holding portion 121b, and a magnet 122.

[0019] The magnet holding portion 121a and the magnet holding portion 121b sandwich a plurality of magnets 122 from both sides in the axial direction. The plurality of magnets 122 are magnetized so as to have alternating polarities in the axial direction.

[0020] The rotating shaft 130 is fixed to the central hole of the rotor 120 and is configured to be rotatable together with the rotor 120. The fixing of the rotating shaft 130 to the central hole of the rotor 120 is performed by any method such as adhesion, press-fitting, or screwing. Although the case where the rotating shaft 130 is a hollow shaft is illustrated, it may be a solid shaft.

[0021] The bearing 140 rotatably holds the rotor 120 with respect to the stator 150 on the radially outer side, i.e., the outer circumference, of the rotor 120. The bearing 140 is provided with an inner ring portion 141, an outer ring portion 142, and a rolling portion 143. The inner ring portion 141 is fixed to the outer circumferential surface on the radially outer side of the rotor 120. The outer ring portion 142 is fixed to the inner circumferential surface 151c on the radially inner side of the first yoke portion 151b of the stator 150 and the inner circumferential surface 110c on the radially inner side of the outer cylindrical portion 110b of the lid portion 110.

[0022] The fixing of the inner ring portion 141 of the bearing 140 to the outer circumferential surface on the radially outer side of the rotor 120, and the fixing of the outer ring portion 142 of the bearing 140 to the inner circumferential surface 151c on the radially inner side of the first yoke portion 151b of the stator 150 and the inner circumferential surface 110c on the radially inner side of the outer cylindrical portion 110b of the lid portion 110 are performed by any method such as adhesion, press-fitting, or screwing.

[0023] The stator 150 is positioned on the rotor 120 so as to face the opposite side from the cover portion 110. The stator 150 comprises a yoke 151, a core 152, and a coil 153.

[0024] The yoke 151 constitutes the magnetic path of the stator 150. The yoke 151 comprises a flat portion 151a, a first yoke portion 151b, an inner circumferential surface 151c, a bottom outer surface 151d, a second yoke portion 151f, a recess 151g, and an inner cylindrical portion 151h.

[0025] The flat portion 151a is the bottom portion configured parallel to the rotor 120. The first yoke portion 151b is provided on the radially outer side, i.e., outer circumference, of the flat portion 151a. The first yoke portion 151b, together with the outer cylinder portion 110b of the cover portion 110, constitutes the outer cylindrical surface of the axial gap motor 100. An inner circumferential surface 151c is provided on the radially inner side, i.e., the inner circumferential surface side, of the first yoke portion 151b. The outer ring portion 142 of the bearing 140 is fixed to the inner circumferential surface 151c. The bottom outer surface 151d constitutes the bottom of the axial gap motor 100.

[0026] The second yoke portion 151f is configured to have a second outer diameter smaller than the first outer diameter, which is the outer diameter of the first yoke portion 151b. The second yoke portion 151f is provided with a plurality of recesses 151g. Each of the plurality of recesses 151g is configured to be able to receive a plurality of convex heat conduction portions 162 that protrude radially inward from the annular heat dissipation portion 161. The inner cylinder portion 151h is configured to allow the rotation of the rotating shaft 130 to be extracted to the outside.

[0027] The core 152 is configured as a magnetic path that protrudes axially from the flat portion 151a of the yoke 151 toward the rotor 120 at equal angular intervals. A coil 153 is wound around the core 152. The coil 153 generates a rotating magnetic field by a drive current supplied from an external drive circuit (not shown). In response to this rotating magnetic field, attractive and repulsive forces act on the magnet 122 of the rotor 120, causing the rotor 120 to rotate in synchronization with the rotating magnetic field caused by the drive current. The rotation of the rotor 120 is transmitted to an external shaft (not shown) attached to the rotating shaft 130.

[0028] The heat dissipation section 160 comprises an annular heat dissipation section 161 and a convex heat conduction section 162. The annular heat dissipation section 161 has an inner diameter corresponding to the outer diameter of the second yoke section 151f and is configured to be attachable to and detachable from the outer circumference of the second yoke section 151f.

[0029] The annular heat dissipation section 161 has an outer diameter corresponding to the outer diameter of the first yoke section 151b, and when attached to the radially outer side, i.e., outer circumference, of the second yoke section 151f, it forms the outer cylindrical surface of the axial gap motor 100 together with the first yoke section 151b and the outer cylindrical section 110b of the cover section 110. In other words, the annular heat dissipation section 161, together with the cover section 110 and the stator 150, constitutes the housing of the axial gap motor 100. This makes it possible to dissipate heat using the heat dissipation section 160 without changing the size of the housing of the axial gap motor 100.

[0030] The annular heat dissipation section 161 is preferably made of a metal such as aluminum with high thermal conductivity. This improves heat dissipation performance and reduces weight. The outer surface of the annular heat dissipation section 161 may have irregularities for heat dissipation. These irregularities include various processes that increase the surface area, such as heat dissipation fins and dimples. The inner surface 163 on the radially inner side of the annular heat dissipation section 161 is provided with multiple grooves 164 for attaching multiple convex heat conduction sections 162.

[0031] Each of the multiple convex heat conductors 162 is removably inserted at one end into a corresponding groove 164 of the annular heat dissipation section 161, and is positioned so that the portion projecting radially inward from the annular heat dissipation section 161 contacts a recess 151g of the stator 150. The convex heat conductors 162 can be inserted into the grooves 164 of the annular heat dissipation section 161 by screwing in with male and female threads or by press-fitting. The convex heat conductors 162 are known rod-shaped heat conductors such as heat pipes, and their function is to transfer heat generated in the core 152 and coil 153 of the stator 150 from the recess 151g to the annular heat dissipation section 161. Figures 1 and 2 show a specific example using 12 convex heat conductors 162, but the number of convex heat conductors 162 can be adjusted without using all of the grooves 164 on the inner circumferential surface 163 of the annular heat dissipation section 161, depending on the need for heat dissipation. By adjusting the number of convex heat conduction sections 162 inserted into the annular heat dissipation section 161, it becomes possible to achieve both efficient heat dissipation and weight reduction.

[0032] Figure 3(e) shows a state in which one end of the rotating shaft 130 coincides with the axially outer side of the flat portion 110a of the cover portion 110, and the other end of the rotating shaft 130 coincides with the bottom outer surface 151d of the yoke 151, but it is not limited to this. That is, the end of the rotating shaft 130 may be located inside the axial gap motor 100, or it may protrude outwards in the axial direction from the axial gap motor 100.

[0033] [Effects obtained by Embodiment 1] The axial gap motor 100 according to Embodiment 1 can achieve the following effects.

[0034] The axial gap motor 100 according to Embodiment 1 comprises a planar rotor 120 with a rotation axis 130 as its center of rotation, a stator 150 arranged to face one side of the rotor 120, and a heat dissipation section 160 provided in contact with the stator 150. Here, the stator 150 is provided with a plurality of recesses 151g, and the heat dissipation section 160 is provided with an annular heat dissipation section 161 and a plurality of convex heat conduction sections 162 that protrude radially inward from the annular heat dissipation section 161 corresponding to the plurality of recesses 151g.

[0035] In other words, in the axial gap motor 100 of Embodiment 1, by attaching the heat dissipation section 160, which has a convex heat conduction section 162 protruding inward from the annular heat dissipation section 161, to the stator 150, which has a recess 151g that matches the convex heat conduction section 162, the heat generated in the stator 150 is transferred from the recess 151g to the annular heat dissipation section 161 via the convex heat conduction section 162 and released to the outside from the surface of the annular heat dissipation section 161. Therefore, efficient heat dissipation can be achieved in the axial gap motor 100 without affecting the structure of the coil.

[0036] In the axial gap motor 100 according to Embodiment 1, the stator 150 is provided with a first yoke portion 151b having a first outer diameter and a second yoke portion 151f having a second outer diameter smaller than the first outer diameter and having a plurality of recesses 151g. The annular heat dissipation portion 161 has an inner diameter corresponding to the outer diameter of the second yoke portion 151f and is provided on the outer circumference of the second yoke portion 151f.

[0037] Here, in the stator 150, an annular heat dissipation section 161 is provided on the outer circumference of the second yoke section 151f, which has a smaller diameter than the first yoke section 151b and has a plurality of recesses 151g, and has a plurality of convex heat conductive sections 162 corresponding to the plurality of recesses 151g. In other words, since the heat dissipation section 160 is provided in the second yoke section 151f, which is the small-diameter region of the stator 150, efficient heat dissipation can be performed in the axial gap motor 100 without affecting the coil structure. Furthermore, the annular heat dissipation section 161 constitutes the outer cylindrical surface of the axial gap motor 100. Therefore, efficient heat dissipation is possible without changing the size of the housing of the axial gap motor 100.

[0038] In the axial gap motor 100 according to Embodiment 1, a bearing 140 is further provided to rotatably hold the rotor 120 with respect to the stator 150, the inner ring portion 141 of the bearing 140 is fixed to the outer circumferential surface of the rotor 120, and the outer ring portion 142 of the bearing 140 is fixed to the inner circumferential surface 151c of the first yoke portion 151b.

[0039] Specifically, the bearing 140 is fixed between the outer circumferential surface of the rotor 120 and the inner circumferential surface 151c of the first yoke portion 151b. The annular heat dissipation portion 161 of the heat dissipation portion 160 is provided on the outer circumference of the second yoke portion 151f, which has a smaller diameter than the first yoke portion 151b. As a result, since both the heat dissipation portion 160 and the bearing 140 are located radially outward, the heat dissipation portion 160 does not affect the structure of the coil, and efficient heat dissipation can be achieved in the axial gap motor 100.

[0040] In the heat dissipation section 160 provided in contact with the stator 150 of the axial gap motor 100 of Embodiment 1, heat dissipation irregularities are formed on the outer circumferential surface of the annular heat dissipation section 161. That is, the heat generated in the stator 150 is transferred from the recess 151g to the annular heat dissipation section 161 via the convex heat conduction section 162, and is released to the outside by the heat dissipation irregularities on the surface of the annular heat dissipation section 161. Therefore, efficient heat dissipation can be achieved in the axial gap motor 100 without affecting the structure of the coil.

[0041] In the axial gap motor 100 according to Embodiment 1, a plurality of grooves 164 are provided on the inner circumferential surface 163 of the annular heat dissipation portion 161, and one end of each of the plurality of convex heat conduction portions 162 is removably inserted into the corresponding groove 164 of the annular heat dissipation portion 161. The portions of the annular heat dissipation portion 161 that protrude radially inward are provided to be in contact with the recesses 151g of the stator 150.

[0042] Therefore, the number of convex heat conduction parts 162 inserted into the grooves 164 on the inner circumferential surface 163 of the annular heat dissipation part 161 may be adjusted according to the heat dissipation requirements of the axial gap motor 100. By reducing the number of convex heat conduction parts 162 inserted into the annular heat dissipation part 161, it is possible to achieve weight reduction. In other words, by adjusting the number of convex heat conduction parts 162 inserted into the annular heat dissipation part 161, it is possible to achieve both efficient heat dissipation and weight reduction.

[0043] Other embodiments In the axial gap motor 100, if the need for heat dissipation is small, the convex heat conduction portion 162 may be omitted entirely, and only the annular heat dissipation portion 161 may be attached to the second yoke portion 151f as the heat dissipation portion 160. Even in this case, the heat generated in the stator 150 is transferred from the surface of the second yoke portion 151f to the annular heat dissipation portion 161 and released to the outside from the surface of the annular heat dissipation portion 161. By keeping the heat dissipation level low as needed, weight reduction can be achieved. In the axial gap motor 100, if the need for heat dissipation is even less, it is possible to omit the heat dissipation section 160. By reducing heat dissipation as needed in this way, further weight reduction can be achieved.

[0044] When a first stator is provided facing one side of the rotor 120 and a second stator is provided facing the other side of the rotor 120, providing heat dissipation sections 160 on both the first and second stators makes it possible to achieve appropriate and efficient heat dissipation without affecting the coil structure or the outer diameter of the housing. [Explanation of Symbols]

[0045] 100 Axial gap motor, 110 Cover, 110a Flat section, 110b Outer cylinder section, 110c Inner circumferential surface, 110h Center hole section, 120 Rotor, 121 Magnet holder section, 121a, 121b Magnet holder section, 122 Magnet, 130 Rotating shaft, 140 Bearing, 141 Inner ring section, 142 Outer ring section, 143 Rolling section, 150 Stator, 151 Yoke, 151a Flat section, 151b First yoke section, 151c Inner circumferential surface, 151d Bottom outer surface, 151f Second yoke section, 151g Recess, 151h Inner cylinder section, 152 Core, 153 Coil, 160 Heat dissipation section, 161 Annular heat dissipation section, 162 Convex heat conduction section, 163 Inner surface, 164 grooves.

Claims

1. A planar rotor (120) with the rotation axis (130) as the center of rotation, A stator (150) is positioned to face one side of the rotor (120), A heat dissipation section (160) is provided so as to be in contact with the stator (150), Equipped with, The stator (150) is provided with a plurality of recesses (151g), The heat dissipation section (160) includes: Annular heat dissipation section (161), A plurality of convex heat conduction portions (162) are provided that protrude radially inward from the annular heat dissipation portion (161) corresponding to the plurality of recesses (151g). Axial gap motor.

2. The stator (150) includes: A first yoke portion (151b) having a first outer diameter, A second yoke portion (151f) is provided, having a second outer diameter smaller than the first outer diameter and having the plurality of recesses (151g). The annular heat dissipation portion (161) has an inner diameter corresponding to the outer diameter of the second yoke portion (151f), and is provided on the outer circumference of the second yoke portion (151f), The axial gap motor according to claim 1.

3. The stator (150) is further provided with a bearing (140) that rotatably holds the rotor (120), The inner ring portion (141) of the bearing (140) is fixed to the outer circumferential surface of the rotor (120), The outer ring portion (142) of the bearing (140) is fixed to the inner circumferential surface (151c) of the first yoke portion (151b). The axial gap motor according to claim 2.

4. The outer surface of the annular heat dissipation portion (161) has irregularities formed on it for heat dissipation. The axial gap motor according to claim 1.

5. Multiple grooves (164) are provided on the inner circumferential surface (163) of the annular heat dissipation portion (161). Each of the plurality of convex heat conduction portions (162) is One end is removably inserted into the corresponding groove (164) of the annular heat dissipation portion (161), The portion of the annular heat dissipation section (161) that protrudes radially inward is the recess (151g) of the stator (150). They are provided so as to be in contact with each other, An axial gap motor according to any one of claims 1 to 4.

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