Stator and motor

Abstract

The goal is to improve stator cooling. [Solution] A stator for an axial gap motor, characterized by comprising: a plurality of core portions arranged at equal intervals in the circumferential direction; a baffle separating one axial side from the other axial side of the plurality of core portions; and a refrigerant flow path that allows refrigerant to flow from the other axial side of the plurality of core portions separated by the baffle to the axial side of the plurality of core portions separated by the baffle.

Description

Technical Field

[0001] The present invention relates to a stator and a motor.

Background Art

[0002] Conventionally, a structure for cooling an axial gap motor has been known. Patent Document 1 discloses a structure in which a port for introducing a coolant is provided at one location on the outer periphery of the stator of an axial gap motor, and a port for discharging the coolant is provided at one location that is half a circumference around the outer periphery of the stator from this introduction port. In Patent Document 1, a coolant is introduced from the introduction port into a closed space that goes around the outside in the radial direction of the stator, and the coolant that has passed through this closed space is discharged from the discharge port, thereby cooling the stator from the outside in the radial direction.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] In Patent Document 1, since the coolant introduced from the introduction port absorbs the heat of the stator when passing through the closed space that goes around the outside in the radial direction of the stator, the temperature of the coolant is different between the vicinity of the introduction port and the vicinity of the discharge port, resulting in a difference in cooling efficiency and uneven temperature of the stator. For this reason, conventionally, there has been room for improvement in cooling the stator.

[0005] The present invention has been made in view of the above points, and an object thereof is to improve the cooling of the stator.

Means for Solving the Problems

[0006] A stator according to one aspect of the present invention is a stator for an axial gap motor, characterized by comprising: a plurality of core portions arranged at equal intervals in the circumferential direction; baffles separating one axial side from the other axial side of the plurality of core portions; and a refrigerant flow path that allows refrigerant to flow from the other axial side of the plurality of core portions separated by the baffles to the one axial side of the plurality of core portions separated by the baffles. [Effects of the Invention]

[0007] According to one aspect of the present invention, stator cooling can be improved. [Brief explanation of the drawing]

[0008] [Figure 1] This is a perspective view of the stator 100 according to Embodiment 1 of the present invention. [Figure 2] This is an exploded perspective view of the stator 100. [Figure 3] This is a partial cross-sectional perspective view of stator 100. [Figure 4] This is a perspective view of the motor 200 according to Embodiment 2 of the present invention. [Figure 5] This is an exploded perspective view of motor 200. [Figure 6] This figure shows the first oil guide member 250 and the second oil guide member 260. [Figure 7] This is a perspective view of the stator 300 according to Embodiment 3 of the present invention. [Figure 8] This is a rear view of the stator 300. [Figure 9] This is a perspective view of the stator case 350. [Modes for carrying out the invention]

[0009] The stator of an axial gap motor according to an embodiment of the present invention will be described below with reference to the drawings. Note that in the following drawings, the scale and number of components in each structure may differ from the actual structure in order to make the components easier to understand.

[0010] <Embodiment 1> Figure 1 is a perspective view of a stator 100 according to Embodiment 1 of the present invention. Figure 2 is an exploded perspective view of the stator 100. The stator 100 is the stator of an axial gap motor. The axial gap motor having the stator 100 rotates around a shaft (not shown) extending along a central axis J as its axis of rotation. The axial gap motor having the stator 100 has one or more rotors (not shown) on one or both sides of the stator 100 in the axial direction, which is the direction in which the central axis J extends.

[0011] Furthermore, in the drawings, the XYZ coordinate system is shown as a three-dimensional Cartesian coordinate system where appropriate. In the XYZ coordinate system, the Z-axis direction is parallel to the axis direction of the central axis J shown in Figure 1. The X-axis direction is the vertical direction in Figure 1, which is the radial direction relative to the central axis J. The Y-axis direction is perpendicular to both the X-axis and Z-axis directions. In all of the X-axis, Y-axis, and Z-axis directions, the side indicated by the arrow in the drawing is the + side, and the opposite side is the - side.

[0012] Furthermore, in the following explanation, the positive side in the Z-axis direction (+Z side) will be referred to as "one side," and the negative side in the Z-axis direction (-Z side) will be referred to as "the other side." Note that "one side" and "the other side" are merely names used for explanatory purposes and do not limit the actual positional relationship or direction. Unless otherwise specified, the direction parallel to the central axis J (Z-axis direction) will be simply referred to as the "axis direction," the radial direction centered on the central axis J will be simply referred to as the "radial direction," and the circumferential direction centered on the central axis J, i.e., around the axis of the central axis J, will be simply referred to as the "circumferential direction." In the radial direction, the side approaching the central axis J will be referred to as the "inside radial direction," and the side moving away from the central axis J will be referred to as the "outside radial direction." In the circumferential direction, the clockwise side when viewed from the +Z side to the -Z side will be referred to as the "one side circumferential," and the counterclockwise side will be referred to as the "other side circumferential."

[0013] In addition, in this specification, "extending in the axial direction" includes not only the case of strictly extending in the axial direction but also the case of extending in a direction inclined within a range of less than 45° with respect to the axial direction. Also, in this specification, "extending in the radial direction" includes not only the case of strictly extending in the radial direction, that is, in a direction perpendicular to the axial direction, but also the case of extending in a direction inclined within a range of less than 45° with respect to the radial direction. Also, "parallel" includes not only the case of being strictly parallel but also the case of being inclined within a range of less than 45° with respect to each other. Also, "spreading in a direction orthogonal to the axial direction" includes not only the case of strictly spreading in a direction orthogonal to the axial direction but also the case of spreading in a direction inclined within a range of less than 45° with respect to the direction orthogonal to the axial direction.

[0014] The stator 100 includes an oil jacket 110, a first core pressing member 120, a core portion 130, a first stator case 140, a second stator case 150, a baffle 160, and a second core pressing member 170.

[0015] The core portion 130 is composed of a stator core and windings wound around the stator core. A plurality of core portions 130 are provided according to the number of slots. The plurality of core portions 130 are arranged at equal intervals in the circumferential direction.

[0016] The first core pressing member 120 is arranged on one axial side of the plurality of core portions 130. One axial side end of each of the plurality of core portions 130 has a part thereof exposed axially on one side from a through hole 121 provided in the first core pressing member 120. The first core pressing member 120 is a flat annular member, and the through hole 121 is a hole penetrating the first core pressing member 120 in the axial direction. The plurality of core portions 130 are pressed from one axial side by the first core pressing member 120.

[0017] On the other axial side of the plurality of core portions 130, a second core pressing member 170 is arranged. A part of each other axial end of the plurality of core portions 130 is exposed axially on the other side through a through hole 171 provided in the second core pressing member 170. The second core pressing member 170 is a flat and annular member, and the through hole 171 is a hole penetrating the second core pressing member 170 axially. The plurality of core portions 130 are pressed from the other axial side by the second core pressing member 170.

[0018] The baffle 160 is a flat and annular member arranged between the first core pressing member 120 and the second core pressing member 170, and has a plurality of protruding portions 161 equal in number to the plurality of core portions 130. Each of the plurality of protruding portions 161 extends from the radially outer side to the radially inner side and is arranged at equal intervals in the circumferential direction. Each of the plurality of core portions 130 is fitted between each protruding portion 161 and an adjacent protruding portion 161, and the baffle 160 is arranged near the axial center of the plurality of core portions 130. The radially inner end of the protruding portion 161 is located radially outside the radially outer end of the first stator case 140.

[0019] The first stator case 140 is a cylindrical member and is fixed between the first core pressing member 120 and the second core pressing member 170 inside the plurality of core portions 130 and the baffle 160 in the radial direction. A gap is provided between the radially inner ends of the plurality of core portions 130 and the radially outer end of the first stator case 140, and a refrigerant, for example, cooling oil, flows through this gap as will be described in detail later. The space between the first core pressing member 120 and the first stator case 140 and the space between the second core pressing member 170 and the first stator case 140 are sealed so that the refrigerant flowing through the refrigerant flow path described later does not leak. A shaft fixed to the rotor of the axial gap motor is arranged inside the first stator case 140 in the radial direction.

[0020] The second stator case 150 is a cylindrical member and is positioned radially outward of the multiple core portions 130, baffles 160, first core retaining member 120, and second core retaining member 170. The outer circumferential surface of the first core retaining member 120 is fixed to the inner circumferential surface of the second stator case 150 on one axial side. The outer circumferential surface of the second core retaining member 170 is fixed to the inner circumferential surface of the second stator case 150 on the other axial side. The space between the first core retaining member 120 and the second stator case 150, and the space between the second core retaining member 170 and the second stator case 150 are sealed to prevent leakage of refrigerant flowing into the refrigerant passage, which will be described later.

[0021] The second stator case 150 has a cylindrical portion 151, a through hole 152 that penetrates the cylindrical portion 151 radially on the other axial side, and a through hole 153 that penetrates the cylindrical portion 151 radially on one axial side. Multiple through holes 152 and 153 are provided in the circumferential direction. The through holes 152 and 153 are offset in the circumferential direction. This ensures the strength of the second stator case 150 compared to a case where the through holes 152 and 153 are not offset in the circumferential direction. In this embodiment, the number of through holes 152 and 153 is the same as the number of multiple core portions 130.

[0022] The oil jacket 110 is fixed radially outward of the first core retaining member 120 and the second core retaining member 170. Figure 3 is a diagram illustrating the flow of refrigerant through the oil jacket 110 and is a partial cross-sectional perspective view of the stator 100. The arrows in Figure 3 indicate the direction of refrigerant flow.

[0023] The oil jacket 110 has a flat, annular top plate portion 115 and a bottom plate portion 116. The oil jacket 110 has a cylindrical portion 114 that connects the top plate portion 115 and the bottom plate portion 116 radially outward. The radially outward surface of the cylindrical portion 114 is exposed to the outside and has cooling fins 117. It is desirable that the oil jacket 110 be made of a material with high thermal conductivity and good heat dissipation.

[0024] The bottom plate portion 116 has a refrigerant inlet 111 for introducing refrigerant into the oil jacket 110, and a refrigerant outlet 112 for releasing refrigerant from the oil jacket 110. The refrigerant inlet 111 and refrigerant outlet 112 are through holes that penetrate the bottom plate portion 116 in the axial direction. Multiple refrigerant inlets 111 and refrigerant outlets 112 are arranged in the circumferential direction, and the stator 100 is configured to be supplied with refrigerant from multiple locations in the circumferential direction. In this embodiment, the number of refrigerant inlets 111 and refrigerant outlets 112 is the same as the number of multiple core portions 130. The oil jacket 110 has a partition wall 113 that separates a refrigerant flow path connecting the refrigerant inlet 111 to the through hole 152 and a refrigerant flow path connecting the through hole 153 to the refrigerant outlet 112.

[0025] The baffle 160 separates one axial side from the other axial side of the multiple core sections 130. The refrigerant flowing into the stator 100 from the refrigerant inlet 111 passes through the through hole 152 of the second stator case 150 and flows around the core section 130 on the axial side of the baffle 160. Subsequently, the refrigerant flows through the gap between the radially inner end of the protrusion 161 of the baffle 160 and the radially outer end of the first stator case 140, and the gap between the radially inner end of the core section 130 and the radially outer end of the first stator case 140, flowing to the axial side of the baffle 160. Subsequently, the refrigerant flows around the core section 130 on the axial side of the baffle 160, passes through the through hole 153 of the second stator case 150, and flows out of the stator 100 from the refrigerant outlet 112. This flow of refrigerant cools the multiple core sections 130.

[0026] The gap between the radially inner end of the protrusion 161 of the baffle 160 and the radially outer end of the first stator case 140, and the gap between the radially inner end of the core portion 130 and the radially outer end of the first stator case 140, are examples of refrigerant flow paths that allow refrigerant to flow from the other axial side of the core portion 130 partitioned by the baffle 160 to the one axial side of the core portion 130 partitioned by the baffle 160.

[0027] In this embodiment, the baffle 160 separates one axial side of the core portion 130 from the other axial side, thereby enabling the formation of a refrigerant flow path. It is desirable to provide sealing material such as a resin member or adhesive at the positions where each component comes into contact with each other to prevent refrigerant leakage at locations other than the aforementioned refrigerant flow path.

[0028] In the refrigerant flow path within the stator 100, the through-holes 152 and 153 are offset in the circumferential direction, which allows for circumferential movement in the refrigerant flow and enables efficient cooling of the area around the stator core 160.

[0029] The refrigerant that flows out of the stator 100 through the refrigerant outlet 112 flows back into the stator 100 through the refrigerant inlet 111 via a pump and refrigerant flow path (not shown) and circulates. The refrigerant is cooled by heat exchange when it comes into contact with the inner surface of the cylindrical portion 114 as it flows out of the stator 100 through the refrigerant outlet 112. In addition, the refrigerant may be cooled by providing a cooling means such as a cooler outside the stator 100.

[0030] In this embodiment, the refrigerant inlet 111 and refrigerant outlet 112 are provided on the other axial side of the stator 100. However, the present invention is not limited to this, and the refrigerant inlet and outlet may be provided at other locations, such as on one axial side of the stator 100, radially outward, or radially inward. Furthermore, the refrigerant may be configured to flow from the refrigerant outlet 112 towards the refrigerant inlet 111.

[0031] According to this embodiment, the baffle 160 is used as a partition member to separate one axial side from the other axial side of the core portion 130, thereby forming a refrigerant flow path that folds back from the refrigerant flow path on the other axial side of the baffle 160 to the refrigerant flow path on the one axial side. This makes it possible to eliminate temperature unevenness in the core portion 130.

[0032] Furthermore, if the other axial side is positioned vertically downwards, the refrigerant, after exchanging heat with the core section 130, rises due to the chimney effect as the refrigerant flows from the refrigerant inlet 111 to the refrigerant outlet 112. This allows the refrigerant to flow more smoothly from the bottom to the top of the baffle 160.

[0033] Furthermore, according to this embodiment, since refrigerant is introduced into the stator 100 from multiple refrigerant inlets 111 in the circumferential direction, multiple core sections 130 can be uniformly cooled in the circumferential direction without temperature unevenness occurring, thereby improving cooling efficiency.

[0034] Furthermore, according to this embodiment, by installing multiple refrigerant inlets 111 and refrigerant outlets 112 in the oil jacket 110, the flow of refrigerant is optimized, and a uniform temperature distribution is achieved within the stator 100.

[0035] <Embodiment 2> Figure 4 is a perspective view of a motor 200 according to Embodiment 2 of the present invention. Figure 5 is an exploded perspective view of the motor 200. The motor 200 according to Embodiment 2 has a stator 100 according to Embodiment 1, and in addition has a configuration for supplying a coolant to the stator 100. The motor 200 is configured by arranging a first rotor 210 on one axial side of the stator 100 with a gap between them, and arranging a second rotor 220 on the other axial side of the stator 100 with a gap between them. A shaft 270 extending along the central axis J is fixed to the first rotor 210 and the second rotor 220. The shaft 270 is the rotation axis of the motor 200.

[0036] The motor 200 has a first oil guide member 250 and a second oil guide member 260 on the axial side opposite the second rotor 220. The motor 200 has a pump 280 on the axial side opposite the direct connection side of the shaft 270.

[0037] Figure 6 shows the first oil guide member 250 and the second oil guide member 260. Figure 6(A) is a side view of the motor 200. Figure 6(B) is a perspective view of the first oil guide member 250 and the pump 280. Figure 6(B) is a perspective view of the second oil guide member 260 and the pump 280.

[0038] The first oil guide member 250 supplies the refrigerant discharged from the discharge port 281 of the pump 280 into the stator 100 from the refrigerant inlet 111. The second oil guide member 260 returns the refrigerant from the refrigerant outlet 112 to the suction port 282 of the pump 280. The pump 280 may be, for example, an internal gear pump that draws in refrigerant from the suction port 282 and discharges refrigerant from the discharge port 281 by the rotation of the shaft 270.

[0039] The first oil guide member 250 has a central portion 253 having a circumferential flow path 253a for circumferentially flowing the refrigerant discharged from the discharge port 281 of the pump 280, a radial portion 252 having a radial flow path 252a for radiating the refrigerant flowing through the circumferential flow path 253a radially outward, and a rising portion 251 having an axial flow path 251a for diverting the refrigerant flowing through the radial flow path 252a to one axial side and into the refrigerant inlet 111. The number of sets of rising portions 251 and radial portions 252 is the same as the number of refrigerant inlets 111.

[0040] The second oil guide member 260 has a rising section 261 having an axial flow path 261a that directs the refrigerant flowing out from the refrigerant outlet 112 to the other axial direction, a radial section 262 having a radial flow path 262a that directs the refrigerant flowing through the axial flow path 261a radially inward, and a central section 263 having a circumferential flow path 263a that directs the refrigerant flowing through the radial flow path 262a circumferentially into the suction port 282 of the pump 280. The number of sets of rising sections 261 and radial sections 252 is the same as the number of refrigerant inlets 111.

[0041] As the shaft 270, which is the rotation axis of the motor 200, rotates, the pump 280 draws in refrigerant from the suction port 282 and discharges it from the discharge port 281. The refrigerant discharged from the discharge port 281 is supplied to the refrigerant inlet 111 by the first oil guide member 250 as described above. The refrigerant that flows out from the refrigerant outlet 112 is returned to the suction port 282 by the second oil guide member 260 as described above.

[0042] According to this embodiment, a pump provided on the side opposite to the direct connection of the motor 200 can supply coolant to the stator 100 using a first oil guide member 250 and a second oil guide member 260, which have a simple configuration. Therefore, a propeller can be provided on the side directly connected to the motor 200, making it suitable for application to drones, for example.

[0043] <Embodiment 3> Figure 7 is a perspective view of the stator 300 according to Embodiment 3 of the present invention. Figure 8 is a rear view of the stator 300. Figure 9 is a perspective view of the stator case 350. The stator 300 according to Embodiment 3 differs from the stator 100 according to Embodiment 1 in that it has an oil jacket 310 instead of the oil jacket 110, and a second stator case 350 instead of the second stator case 150. Other configurations are the same as in Embodiment 1, so the same reference numerals are used for the same configurations as in Embodiment 1, and detailed explanations are omitted.

[0044] The oil jacket 310 is fixed to the radially outer side of the first core retaining member 120 and the second core retaining member 170. The oil jacket 310 has a flat, annular top plate portion 315 and a bottom plate portion 316. The oil jacket 310 has a cylindrical portion 314 that connects the top plate portion 315 and the bottom plate portion 316 radially outward. The radially outer surface of the cylindrical portion 314 is exposed to the outside and has cooling fins 317. It is desirable that the oil jacket 310 be made of a material with high thermal conductivity and good heat dissipation.

[0045] The cylindrical portion 314 has a refrigerant inlet 311 for introducing refrigerant into the oil jacket 310, and a refrigerant outlet 312 for releasing refrigerant from the oil jacket 310. The refrigerant inlet 311 and the refrigerant outlet 312 are through holes that penetrate the cylindrical portion 314 radially. The refrigerant inlet 311 is located circumferentially on the axial side of the axial center of the cylindrical portion 314 and is configured to supply refrigerant into the stator 300. The refrigerant outlet 312 is located circumferentially on the axial side of the axial center of the cylindrical portion 314 and is configured to discharge refrigerant from the stator 300. The circumferential position of the refrigerant outlet 312 is offset by 180 degrees in the circumferential direction from the circumferential position of the refrigerant inlet 311. The oil jacket 310 does not have the configuration corresponding to the refrigerant inlet 111, refrigerant outlet 112, and partition wall 113 of the oil jacket 110 according to Embodiment 1.

[0046] The second stator case 350 is a cylindrical member and is positioned radially outward of the multiple core portions 130, baffles 160, first core retaining member 120, and second core retaining member 170. The outer circumferential surface of the first core retaining member 120 is fixed to the inner circumferential surface of the second stator case 350 on one axial side. The outer circumferential surface of the second core retaining member 170 is fixed to the inner circumferential surface of the second stator case 350 on the other axial side. The space between the first core retaining member 120 and the second stator case 350, and the space between the second core retaining member 170 and the second stator case 350 are sealed to prevent refrigerant from leaking out of the stator 300.

[0047] The second stator case 350 has a cylindrical portion 351, a through hole 352 that penetrates the cylindrical portion 351 radially on the other axial side, and a through hole 353 that penetrates the cylindrical portion 351 radially on one axial side. Multiple through holes 352 and 353 are provided in the circumferential direction. Multiple through holes 352 are arranged in the circumferential direction, and the circumferential width of the through holes 352 is smaller the closer they are to the refrigerant inlet 311 in the circumferential direction. Multiple through holes 353 are arranged in the circumferential direction, and the circumferential width of the through holes 353 is smaller the closer they are to the refrigerant outlet 312 in the circumferential direction. The opening area of ​​the through holes 352 is smaller the closer they are to the refrigerant inlet 311 in the circumferential direction, and the opening area of ​​the through holes 353 is smaller the closer they are to the refrigerant outlet 312 in the circumferential direction.

[0048] In this embodiment, from a cost perspective, there is only one refrigerant inlet 311 and one refrigerant outlet 312. In this case, the size of the through holes 352 and 353 of the second stator case 350 is adjusted. When the number of refrigerant inlets and outlets of the oil jacket is small, the flow rate is not evenly distributed in the circumferential direction, resulting in a temperature distribution in the circumferential direction. In this case, pressure loss occurs depending on the distance from the refrigerant inlet and outlet of the oil jacket, and the flow rate of the refrigerant at the refrigerant inlet and outlet of the stator case changes accordingly. In this embodiment, to address this problem, the pressure loss is controlled and the flow rate of the refrigerant is adjusted by appropriately designing the size of the through holes 352 and 353, which are the refrigerant inlet and outlet of the second stator case 350. Specifically, the through holes 352 and 353 of the second stator case 350 that are far from the refrigerant inlet 311 and refrigerant outlet 312 of the oil jacket 310 are designed to be large, and those that are close are designed to be small, thereby correcting the flow rate change due to pressure loss and achieving a uniform cooling effect overall.

[0049] The present invention is not limited to the embodiments described above, and various improvements and design modifications may be made without departing from the spirit of the invention. In addition, the embodiments disclosed herein should be considered in all respects to be illustrative and not restrictive. The scope of the present invention is indicated by the claims rather than by the above description, and all modifications within the meaning and scope equivalent to the claims are intended to be included. [Explanation of symbols]

[0050] 100...Status 110… Oil jacket 120...First core retaining member 130... Core part 140…First stator case 150...Second stator case 160... Baffle 170...Second core retaining member

Claims

1. The stator of an axial gap motor, Multiple core sections arranged at equal intervals in the circumferential direction, A baffle that separates one axial side from the other axial side of the plurality of core portions, A refrigerant flow path is provided for flowing refrigerant from the other axial side of the plurality of core portions separated by the baffle to one axial side of the plurality of core portions separated by the baffle, A stator characterized by having the following features.

2. Each of the aforementioned multiple core sections is composed of a stator core and windings wound around the stator core. The stator according to feature 1.

3. The oil jacket has a refrigerant inlet for introducing refrigerant to the other axial side of the plurality of core portions and a refrigerant outlet for releasing refrigerant from one axial side of the plurality of core portions on the other axial side, The refrigerant inlets and outlets are arranged in multiple locations in the circumferential direction according to each of the multiple core sections. The stator according to feature 1.

4. The stator according to claim 3, A rotor is positioned with a gap between it and the stator, A shaft fixed to the rotor, A pump fixed to the aforementioned shaft, which, by the rotation of the shaft, discharges refrigerant drawn in from the suction port through the discharge port, A first oil guide member in a flow path supplies the refrigerant discharged from the discharge port into the stator from the refrigerant inlet, A second oil guide member that returns the refrigerant from the refrigerant outlet to the suction port 282, A motor characterized by having the following features.

5. The stator has a stator case that covers the plurality of core parts from the radially outer side, and an oil jacket that covers the stator case from the radially outer side. The stator case has a first through-hole that penetrates radially on the other axial side of the plurality of core portions, and a second through-hole that penetrates radially on one axial side of the plurality of core portions. The oil jacket has a refrigerant inlet through the first through-hole that allows refrigerant to flow into the other axial side of the plurality of core portions, and a refrigerant outlet through the second through-hole that allows refrigerant to flow out from one axial side of the plurality of core portions. The circumferential position of the refrigerant outlet is offset by 180 degrees in the circumferential direction from the circumferential position of the refrigerant inlet. Multiple first through-holes are arranged in the circumferential direction of the stator case, and the opening area of ​​the first through-holes decreases as they approach the refrigerant inlet in the circumferential direction. Multiple second through-holes are arranged in the circumferential direction of the stator case, and the opening area becomes smaller the closer it is to the refrigerant outlet in the circumferential direction. The stator according to feature 1.

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