Motor and traveling vehicle

Abstract

To provide an axial (gap) motor that is used in an in-wheel motor, and that allows for adjusting a gap in an axial direction between a stator and a rotor accurately and easily, and maintaining the adjusted gap in a stable state.SOLUTION: A shaft is arranged along a central axis extending vertically. A bush is connected to the shaft radially outside the shaft relatively unrotatably with respect to the shaft, and extends vertically. A stator is fixed to the bush radially outside the bush. A first bearing is arranged above the bush. A second bearing is arranged below the bush. A first rotor is arranged above the stator. A second rotor is arranged below the stator. The first bearing is supported between a lower surface of the first rotor and an upper surface of the bush. The second bearing is supported between an upper surface of the second rotor and a lower surface of the bush. The first rotor and the second rotor are fixed to each other radially outside the stator.SELECTED DRAWING: Figure 2

Description

[Technical Field]

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

[0002] Conventionally, so-called in-wheel motors have been known in which a motor that rotates a tire wheel is disposed inside the tire wheel. For example, Japanese Patent Application Laid-Open Publication No. 2008-155769 discloses an in-wheel motor that includes an axial motor in which a stator and a rotor are disposed opposite each other in the direction of their rotation axis, and a braking device that brakes the rotation of a cylindrical wheel with a bottom, to which the rotor is fixed inside. [Patent Document 1] Japanese Patent Application Laid-Open No. 2008-155769 Summary of the Invention [Problem to be solved by the invention]

[0003] In the in-wheel motor of the above publication, a cylindrical rotating shaft that rotatably supports the wheel is press-fitted into the inner ring of a bearing. The outer rings of the multiple bearings are press-fitted into the inner surface of a cylindrical bearing seat with an expanded diameter. The stator of the axial motor has an annular stator base plate that extends radially outward from the tip of the bearing seat. On the lateral outer surface of the stator base plate, fan-shaped magnetic cores are evenly arranged in the circumferential direction, and coils are wound around the magnetic cores. The rotor of the axial motor is composed of annular permanent magnets that are arranged on the inner surface of the disk portion of the wheel so as to face the stator in the axial direction. The permanent magnets are magnetized so that adjacent magnets have opposite polarities.

[0004] However, in an axial motor, it is difficult to adjust the axial gap between the stator and rotor, which can lengthen the assembly time and / or reduce the accuracy of the gap size.

[0005] An object of the present invention is to provide a technology that enables accurate and easy adjustment of the axial gap between the stator and rotor in an axial (gap) motor used in an in-wheel motor, and maintains it in a stable state. [Means for solving the problem]

[0006] A first exemplary invention of the present application is a motor having a shaft, a bushing, a stator, a first bearing, a second bearing, a first rotor, and a second rotor. The shaft is arranged along a central axis extending in the vertical direction. The bushing is connected radially outward of the shaft so as to be non-rotatable relative to the shaft and extends in the vertical direction. The stator is fixed radially outward of the bushing. The first bearing is arranged above the bushing. The second bearing is arranged below the bushing. The first rotor is arranged above the stator. The second rotor is arranged below the stator. The first bearing is supported between a lower surface of the first rotor and an upper surface of the bushing. The second bearing is supported between an upper surface of the second rotor and a lower surface of the bushing. The first bearing supports the first rotor rotatably relative to the shaft. The second bearing supports the second rotor rotatably relative to the shaft. The first rotor and the second rotor are fixed to each other in the vertical direction radially outward of the stator. [Effects of the Invention]

[0007] According to a first exemplary aspect of the present application, the first bearing is supported between the lower surface of the first rotor and the upper surface of the bushing, and the second bearing is supported between the upper surface of the second rotor and the lower surface of the bushing, thereby making it possible to adjust the internal clearances of the first bearing and the second bearing. This makes it possible to more accurately and easily adjust the gaps between the stator fixed to the bushing and the first and second rotors, and to maintain them in a stable state. [Brief explanation of the drawings]

[0008] [Figure 1] FIG. 1 is a partial cross-sectional view of a vehicle. [Figure 2] FIG. 2 is a vertical cross-sectional view of the motor and the tire wheel. [Figure 3] FIG. 3 is a vertical cross-sectional view of a motor and a tire wheel according to a first modified example. [Figure 4] FIG. 4 is a plan view of the stator. [Figure 5] FIG. 5 is a vertical cross-sectional view for explaining the positional relationship between the stator, the first rotor, the second rotor, the first bearing, and the second bearing. DETAILED DESCRIPTION OF THE INVENTION

[0009] Hereinafter, exemplary embodiments of the present application will be described with reference to the drawings. In this application, a direction parallel to the central axis of a motor according to the present invention will be referred to as the "axial direction," a direction perpendicular to the central axis will be referred to as the "radial direction," and a direction along an arc centered on the central axis will be referred to as the "circumferential direction."

[0010] In addition, in this application, the direction of the central axis of the motor is defined as the up-down direction, and the right side in Figures 1, 2, 3, and 5 is defined as "up" and the left side as "down," and the shape and positional relationship of each part will be described. However, this definition is not intended to limit the orientation of the motor and running vehicle according to the present invention during manufacture and use. In addition, in this application, the term "parallel direction" is not limited to being geometrically strictly parallel. In other words, it is sufficient that a certain direction and a "parallel direction" to that direction are approximately parallel to each other to the extent that the effects of the invention are achieved. In addition, in this application, the term "orthogonal direction" is not limited to being geometrically strictly orthogonal. In other words, it is sufficient that a certain direction and a "orthogonal direction" to that direction are approximately orthogonal to each other to the extent that the effects of the invention are achieved.

[0011] <1. Motor and running vehicle configuration> The following describes the configuration of a traveling vehicle 100 including a motor 1 according to one embodiment of the present invention. Fig. 1 is a partial cross-sectional view of the traveling vehicle 100. Fig. 2 is a vertical cross-sectional view of the motor 1 and a tire wheel 2, which will be described later. Note that in Fig. 1, the motor 1 and the tire wheel 2 are fastened to each other with screws 45 (bolts) so that they can be separated, whereas in Fig. 2, the motor 1 and the tire wheel 2 are integrally constructed.

[0012] A traveling vehicle 100 of the present invention is used, for example, as a mobility that travels at medium to high speeds. As shown in FIG. 1, the traveling vehicle 100 has a motor 1, a tire wheel 2, and a tire 3. The tire wheel 2 holds the tire 3. The traveling vehicle 100 moves by transmitting rotational motion obtained from the motor 1 to the tire wheel 2, causing the tire 3 to rotate.

[0013] The motor 1 and the traveling vehicle 100 are arranged along a central axis 90 that extends vertically. As shown in Figure 2, the motor 1 has a shaft 10, a bushing 20, a stator 30, a first rotor 41, a second rotor 42, a rotor connecting portion 43, a first bearing 51, and a second bearing 52.

[0014] The shaft 10 is disposed along a central axis 90. The shaft 10 is fixed to a frame provided on the traveling vehicle 100 so as not to rotate, for example. The shaft 10 of this embodiment is a so-called solid shaft. A hollow portion 110 is provided inside the shaft 10. The hollow portion 110 extends axially inside the shaft 10 and opens to the outer circumferential surface of the shaft 10. With this structure, wiring 15 connected to a stator 30 (described later) can be inserted through the opening in the outer circumferential surface of the shaft 10 and extended to the outside of the motor 1 via the hollow portion 110. In other words, the wiring 15 is disposed so as to be able to pass through the hollow portion 110. However, as shown in a first modified example in FIG. 3 , the shaft 10 may be a hollow shaft that extends cylindrically around the central axis 90 along the central axis 90.

[0015] The bushing 20 is an annular member extending around the central axis 90, with its radially inner portion extending in the vertical direction. The bushing 20 is disposed radially outward of the shaft 10. The inner peripheral surface of the bushing 20 is connected to the outer peripheral surface of the shaft 10 via a spline connection. That is, the bushing 20 is connected radially outward of the shaft 10 so as not to rotate relative to the shaft 10 and extends in the vertical direction. This allows the bushing 20 to be firmly connected to the shaft 10. However, the inner peripheral surface of the bushing 20 may be fixed to the outer peripheral surface of the shaft 10 by press-fitting, bonding, welding, or other methods. The bushing 20 and the shaft 10 may also be formed from a single member. This reduces the number of parts in the entire motor 1.

[0016] The bushing 20 includes a boss portion 21 and an annular plate portion 22. The boss portion 21 is a portion that extends cylindrically in the axial direction around the shaft 10. The inner peripheral surface of the boss portion 21 is connected to the outer peripheral surface of the shaft 10 via a spline connection. The annular plate portion 22 is a portion that expands radially outward from near the axial center of the boss portion 21. The annular plate portion 22 expands radially outward from the boss portion 21 in the shape of an annular plate centered on the central axis 90. The stator 30 is fixed to the radially outer end of the annular plate portion 22.

[0017] 2, an opening 210 is provided inside the boss portion 21. In this embodiment, the opening 210 penetrates the boss portion 21 in the radial direction. The radially inner end of the opening 210 is adjacent to the opening at the lower end of the cavity 110 formed in the outer peripheral surface of the shaft 10. The radially outer end of the opening 210 is close to the stator 30.

[0018] As shown in a first modified example in FIG. 3, the boss portion 21 and the shaft 10 may be formed from a single member. Furthermore, as shown in the first modified example in FIG. 3, the shaft 10 may be a hollow shaft. In the modified example in FIG. 3, it is desirable that the hollow portion 110 of the boss portion 21 (shaft 10) be configured to extend axially inside the boss portion 21 (shaft 10), bend, and open on the outer circumferential surface of the boss portion 21 (shaft 10). With this configuration, the wiring 15 connected to the stator 30 can be inserted through the opening on the outer circumferential surface of the boss portion 21 (shaft 10) and led out to the outside of the motor 1 through the hollow portion 110.

[0019] 4 is a plan view of the stator 30 of FIG. 2 as viewed from above. The stator 30 is a stator of the motor 1. As described above, the stator 30 is fixed radially outward of the bush 20. The stator 30 is also arranged in an annular shape in the circumferential direction around the central axis 90.

[0020] As shown in Figures 2 and 4, the stator 30 has a stator core 31, a plurality of (12 in this embodiment) upper coils 321 arranged in the circumferential direction, and a plurality of (12 in this embodiment) lower coils 322 arranged in the circumferential direction.

[0021] The stator core 31 has a stator base portion 311 that extends in the shape of an annular plate in the circumferential direction centered on the central axis 90, a plurality (12 in this embodiment) of upper tooth portions 312, and a plurality (12 in this embodiment) of lower tooth portions.

[0022] The twelve upper teeth 312 each protrude upward from the upper surface of the stator base 311. The twelve upper teeth 312 are arranged at approximately equal angular intervals in the circumferential direction. Each upper coil 321 is formed by winding a conductive wire around each upper tooth 312 via a resin insulator (not shown). The magnetic core of each upper coil 321 faces the axial direction.

[0023] Each of the 12 lower teeth protrudes downward from the lower surface of the stator base 311. The 12 lower teeth are arranged at approximately equal angular intervals in the circumferential direction. Each lower coil 322 is formed by winding a conductive wire around each lower tooth via a resin insulator (not shown). The magnetic core of each lower coil 322 faces the axial direction.

[0024] The wires 15 drawn from the upper coils 321 and the lower coils 322 are routed while passing through the openings 210 inside the boss portion 21 and the hollow portion 110 inside the shaft 10. This allows the wires 15 to be drawn to the outside of the motor 1 and connected to a power supply device or the like.

[0025] The first rotor 41 is a rotor of the motor 1. The first rotor 41 is disposed above the stator 30. The first rotor 41 extends in an annular shape in the circumferential direction around the central axis 90, radially outward from the shaft 10. The first rotor 41 is supported on the outer peripheral surface of the shaft 10 via a first bearing 51. The first rotor 41 has a first rotor yoke 411, a first magnet 412, a first flange portion 413, a first adjustment portion 414, and a first fin 415.

[0026] The first rotor yoke 411 is supported by the first bearing 51 and is a portion that extends in the shape of an annular plate in the circumferential direction about the central axis 90. The first magnet 412 is a permanent magnet that is fixed to the lower surface of the first rotor yoke 411 in a position facing the twelve upper coils 321. The lower surface of the first magnet 412 faces the upper surfaces of the upper teeth portions 312 of the stator 30 in the axial direction with a small gap between them. That is, the first rotor 41 has the first magnet 412 that faces the stator 30 in the up-down direction. Furthermore, the first magnet 412 has north and south poles that are alternately arranged at approximately equal angular intervals in the circumferential direction about the central axis 90.

[0027] The second rotor 42 is a rotor of the motor 1. The second rotor 42 is disposed below the stator 30. The second rotor 42 extends in an annular shape in the circumferential direction around the central axis 90, radially outward from the shaft 10. The second rotor 42 is supported on the outer peripheral surface of the shaft 10 via a second bearing 52. The second rotor 42 has a second rotor yoke 421, a second magnet 422, a second flange portion 423, a second adjustment portion 424, and a second fin 425.

[0028] The second rotor yoke 421 is supported by the second bearing 52 and is a portion that extends in the shape of an annular plate in the circumferential direction about the central axis 90. The second magnet 422 is a permanent magnet that is fixed to the upper surface of the second rotor yoke 421 at a position facing the twelve lower coils 322. The upper surface of the second magnet 422 faces the lower surface of the lower teeth portion of the stator 30 in the axial direction with a small gap between them. That is, the second rotor 42 has the second magnet 422 that faces the stator 30 in the up-down direction. Furthermore, the second magnet 422 has north and south poles that are alternately arranged at approximately equal angular intervals in the circumferential direction about the central axis 90.

[0029] A through hole 410 is provided near the radially outer end of the first rotor yoke 411. The through hole 410 passes through the first rotor yoke 411 in the axial direction at a location near the radially outer end.

[0030] Furthermore, a rotor coupling portion 43 is further provided between the first rotor yoke 411 and the second rotor yoke 421 in the axial direction. The rotor coupling portion 43 extends cylindrically upward from the radially outer end of the second rotor yoke 421 around and along the central axis 90. A first screw hole 430 is provided at the upper end of the rotor coupling portion 43. The first screw hole 430 is formed downward from the end face of the upper end of the rotor coupling portion 43.

[0031] The rotor coupling portion 43 extending upward from the second rotor yoke 421 is fixed to the first rotor yoke 411 by fastening screws 44 passing through the through holes 410 of the first rotor yoke 411 into the first screw holes 430. This causes the first rotor 41 and the second rotor 42 to be fixed to each other in the vertical direction, radially outward of the stator 30.

[0032] The detailed structures of the first flange portion 413, first adjustment portion 414, and first fin 415 of the first rotor 41, and the second flange portion 423, second adjustment portion 424, and second fin 425 of the second rotor 42 will be described later.

[0033] The first bearing 51 is disposed above the bush 20. The second bearing 52 is disposed below the bush 20. For example, a pair of angular ball bearings is used for the first bearing 51 and the second bearing 52. The pair of first bearing 51 and second bearing 52 is disposed facing in opposite directions (face-to-face combination) with a gap between them in the axial direction. However, ball bearings other than angular ball bearings may be used for the first bearing 51 and the second bearing 52, and tapered roller bearings may also be used. In other words, it is sufficient that the first bearing 51 and the second bearing 52 are rolling bearings.

[0034] More specifically, the first bearing 51 has a first inner ring 511, a plurality of first rolling elements 512, and a first outer ring 513. The first inner ring 511 is supported on the outer peripheral surface of the shaft 10. The first outer ring 513 is supported on the inner peripheral surface of the first rotor yoke 411. The plurality of first rolling elements 512 are interposed between the first inner ring 511 and the first outer ring 513. In other words, the first bearing 51 is a rolling bearing having the first outer ring 513 and the first inner ring 511 that sandwich the first rolling elements 512 between them in the radial direction. This allows the first bearing 51 to stably support the first rotor 41 so as to be rotatable relative to the shaft 10.

[0035] The second bearing 52 has a second inner ring 521, a plurality of second rolling elements 522, and a second outer ring 523. The second inner ring 521 is supported on the outer peripheral surface of the shaft 10. The second outer ring 523 is supported on the inner peripheral surface of the second rotor yoke 421. The plurality of second rolling elements 522 are interposed between the second inner ring 521 and the second outer ring 523. In other words, the second bearing 52 is a rolling bearing having the second outer ring 523 and the second inner ring 521 that sandwich the second rolling elements 522 between them in the radial direction. This allows the second bearing 52 to stably support the second rotor 42 so that it can rotate relative to the shaft 10.

[0036] When the motor 1 is driven, a driving current is supplied to each of the upper coils 321 and each of the lower coils 322 of the stator 30 via the wiring 15. This generates a rotating magnetic field in each of the upper coils 321 and each of the lower coils 322. Then, between the stator core 31 and the first magnet 412 of the first rotor 41 and the second magnet 422 of the second rotor 42, repeated attraction and repulsion due to magnetic forces centered on the central axis 90 generates circumferential torque in the first rotor 41 and the second rotor 42. As a result, the first rotor 41, the second rotor 42, and the rotor coupling portion 43 rotate circumferentially around the central axis 90 relative to the shaft 10 via the first bearing 51 and the second bearing 52.

[0037] As described above, the motor 1 of this embodiment is an axial (gap) motor in which the stator 30 faces the first magnet 412 of the first rotor 41 and the second magnet 422 of the second rotor 42 in the axial direction. By using an axial gap motor as the motor 1, the axial dimension of the motor 1 can be reduced compared to when an outer rotor or inner rotor motor with equivalent performance is used.

[0038] In particular, the motor 1 of this embodiment has two magnets 412, 422 arranged on either side of the stator 30. This allows the torque output from the motor 1 to be increased compared to when magnets are arranged on only one side of the stator 30.

[0039] However, the present invention does not exclude a configuration in which magnets are arranged on only one side of the stator 30 in the motor 1. That is, the present invention only requires that the motor 1 have at least one of the following configurations: the first rotor 41 has a first magnet 412 that faces the stator 30 in the up-down direction, or the second rotor 42 has a second magnet 422 that faces the stator 30 in the up-down direction. Also, the stator 30 only requires that at least one of the plurality of upper coils 321 and the plurality of lower coils 322 faces two of the magnets 412, 422 in the up-down direction.

[0040] As shown in Fig. 1, a second screw hole 435 is provided in the lower end of the rotor coupling portion 43. The second screw hole 435 is formed upward from the end face of the lower end of the rotor coupling portion 43. The tire wheel 2 is disposed radially outward from the rotor coupling portion 43. The tire wheel 2 is provided with a through hole 200. The through hole 200 axially penetrates a portion of the tire wheel 2 near its radially inner end.

[0041] The tire wheel 2 is fixed to the rotor connecting portion 43 by fastening a screw 45 passing through the through hole 200 into a second screw hole 435 at the lower end of the rotor connecting portion 43. This gives the tire wheel 2 a structure that extends radially outward from near the radially outer end of the second rotor 42. However, the position and method for fixing the tire wheel 2 are not limited to this. The tire wheel 2 only needs to have a structure that extends radially outward from at least one of the first rotor 41 and the second rotor 42 of the motor 1.

[0042] As described above, the tire 3 is held on the wheel 2. Therefore, when the motor 1 is driven, the rotation of the first rotor 41 and the second rotor 42 can be transmitted to the tire 3 via the wheel 2. This allows the traveling vehicle 100 to rotate the tire 3 in the circumferential direction, resulting in a traveling vehicle 100 with high driving force. In addition, since the wheel 2 can be attached and detached to the motor 1 using the screws 45, repair and replacement of the tire 3 can be facilitated. Furthermore, by removing the wheel 2, the motor 1 of the present invention can be used alone in various electrical appliances (e.g., washing machines or electric fans) and testing machines (e.g., centrifuges) that do not have wheel or tire components.

[0043] In this embodiment, a plurality of first fins 415 are provided on the upper surface of the first rotor yoke 411 of the first rotor 41, protruding upward from a plurality of positions in the circumferential direction. That is, the first rotor 41 has a plurality of first fins 415 that are provided at intervals from one another in the circumferential direction and protrude upward. Each of the plurality of first fins 415 is connected to the radially outer end surface of the first flange portion 413. By providing such a plurality of first fins 415, the weight of the first rotor 41 can be reduced while improving its strength. Furthermore, when the motor 1 is driven, the first rotor 41 including the plurality of first fins 415 rotates in the circumferential direction, thereby cooling the inside of the motor 1.

[0044] In this embodiment, the second rotor 42 has a plurality of second fins 425 on the underside of the second rotor yoke 421 of the second rotor 42, each protruding downward from a plurality of circumferential positions. That is, the second rotor 42 has a plurality of second fins 425 that are spaced apart from one another in the circumferential direction and each protrude downward. Each of the second fins 425 is connected to the radially outer end surface of the second flange portion 423. By providing such a plurality of second fins 425, the weight of the second rotor 42 can be reduced while improving its strength. Furthermore, when the motor 1 is driven, the second rotor 42, including the plurality of second fins 425, rotates in the circumferential direction, thereby cooling the interior of the motor 1.

[0045] <2. Adjusting the relative positions of the stator, first rotor, and second rotor> Next, a description will be given of adjustment of the positional relationship between the stator 30, the first rotor 41, and the second rotor 42. Fig. 5 is a vertical cross-sectional view for explaining the positional relationship between the stator 30, the first rotor 41, the second rotor 42, the first bearing 51, and the second bearing 52.

[0046] As described above, the first rotor 41 is further provided with the first flange portion 413 and the first adjustment portion 414. The first flange portion 413 extends upward from the radially inner end of the first rotor yoke 411 in a cylindrical shape around the central axis 90 along the central axis 90. The first adjustment portion 414 extends radially inward from the upper end of the first flange portion 413. Furthermore, the first adjustment portion 414 extends radially outward from the shaft 10 in a circular plate shape in the circumferential direction centered on the central axis 90. The first adjustment portion 414 is located at the radially innermost end of the first rotor 41.

[0047] When the first outer ring 513 of the first bearing 51 is supported on the inner peripheral surface of the first rotor yoke 411, the lower surface of the first adjustment part 414 comes into contact with the upper surface of the first outer ring 513. That is, the upper surface of the first outer ring 513 comes into contact with the lower surface of the radially inner end of the first rotor 41. Furthermore, when the first inner ring 511 of the first bearing 51 is supported on the outer peripheral surface of the shaft 10, the lower surface of the first inner ring 511 comes into contact with the upper surface of the boss portion 21 of the bushing 20. As a result, the first bearing 51 is supported between the lower surface of the first rotor 41 and the upper surface of the bushing 20.

[0048] As described above, the second rotor 42 is further provided with the second flange portion 423 and the second adjustment portion 424. The second flange portion 423 extends downward from the radially inner end of the second rotor yoke 421, around the central axis 90, and in a cylindrical shape along the central axis 90. The second adjustment portion 424 extends radially inward from the lower end of the second flange portion 423. The second adjustment portion 424 also extends radially outward from the shaft 10, in a circular plate shape in the circumferential direction centered on the central axis 90. The second adjustment portion 424 is located at the radially innermost end of the second rotor 42.

[0049] When the second outer ring 523 of the second bearing 52 is supported on the inner peripheral surface of the second rotor yoke 421, the upper surface of the second adjustment part 424 contacts the lower surface of the second outer ring 523. That is, the lower surface of the second outer ring 523 contacts the upper surface of the radially inner end of the second rotor 42. Furthermore, when the second inner ring 521 of the second bearing 52 is supported on the outer peripheral surface of the shaft 10, the upper surface of the second inner ring 521 contacts the lower surface of the boss portion 21 of the bushing 20. As a result, the second bearing 52 is supported between the upper surface of the second rotor 42 and the lower surface of the bushing 20.

[0050] In the first bearing 51 of this embodiment, there are small gaps (hereinafter referred to as "internal gaps") between the multiple first rolling elements 512 and the first inner ring 511, and between the multiple first rolling elements 512 and the first outer ring 513. The first bearing 51 is capable of adjusting the size of the internal gaps. More specifically, in the first bearing 51, the first inner ring 511 can be moved upward relative to the multiple first rolling elements 512, and the first outer ring 513 can be moved downward. This gradually reduces the size of the internal gaps. In the structure of this embodiment, the boss portion 21 determines the axial position of the first inner ring 511. The first adjustment portion 414 determines the axial position of the first outer ring 513. This determines the size of the internal gaps. As a result, after the size of the internal gaps has been adjusted, the size of the internal gaps is maintained in a stable state even when the motor 1 is running.

[0051] In the second bearing 52 of this embodiment, there are small gaps (internal gaps) between the second rolling elements 522 and the second inner ring 521, and between the second rolling elements 522 and the second outer ring 523. The second bearing 52 is capable of adjusting the size of the internal gaps. More specifically, in the second bearing 52, the second inner ring 521 can be moved downward relative to the second rolling elements 522, and the second outer ring 523 can be moved upward. This gradually reduces the size of the internal gaps. In the structure of this embodiment, the boss portion 21 determines the axial position of the second inner ring 521. The second adjustment portion 424 determines the axial position of the second outer ring 523. This determines the size of the internal gaps. As a result, after the size of the internal gaps is adjusted, the size of the internal gaps is maintained in a stable state even when the motor 1 is running.

[0052] With this structure, the axial gap between the stator 30 fixed to the bushing 20 with which the lower surface of the first inner ring 511 of the first bearing 51 and the upper surface of the second inner ring 521 of the second bearing 52 come into contact, and the first rotor 41 with which the upper surface of the first outer ring 513 of the first bearing 51 comes into contact and the second rotor 42 with which the lower surface of the second outer ring 523 of the second bearing 52 comes into contact can be accurately and easily adjusted and maintained in a stable state. As a result, the axial gap between the stator 30 and the first magnet 412 fixed to the first rotor 41 and the second magnet 422 fixed to the second rotor 42 can be accurately and easily adjusted and maintained in a stable state.

[0053] In particular, in this embodiment, during the adjustment stage during assembly of the motor 1, a shim 60 is interposed between the upper surface of the boss portion 21 of the bushing 20 and the lower surface of the first inner ring 511. Similarly, shims 60 are interposed between the upper surface of the first outer ring 513 and the lower surface of the first adjustment portion 414 of the first rotor 41, between the lower surface of the boss portion 21 of the bushing 20 and the upper surface of the second inner ring 521, and between the lower surface of the second outer ring 523 and the upper surface of the second adjustment portion 424 of the second rotor 42. The shim 60 is a member that extends in the shape of an annular plate in the circumferential direction about the central axis 90 and has an axial thickness of approximately several tenths of a millimeter. The number of these shims 60 may be one or more. Furthermore, the number of shims 60 may be zero (i.e., no shims 60 are interposed). By interposing the shim 60, even if there is a large initial variation in the internal gap of the first bearing 51 or the second bearing 52, this can be adjusted.

[0054] In this way, in this embodiment, during the adjustment stage during the assembly of the motor 1, it is possible to more easily fine-tune the axial gaps between the upper surface of the boss portion 21 of the bushing 20 and the lower surface of the first inner ring 511, between the upper surface of the first outer ring 513 and the lower surface of the first adjustment portion 414 of the first rotor 41, between the lower surface of the boss portion 21 of the bushing 20 and the upper surface of the second inner ring 521, and between the lower surface of the second outer ring 523 and the upper surface of the second adjustment portion 424 of the second rotor 42.

[0055] This makes it possible to more accurately and easily adjust the axial gap between the stator 30 fixed to the bushing 20 with which the lower surface of the first inner ring 511 of the first bearing 51 and the upper surface of the second inner ring 521 of the second bearing 52 come into contact, and the first rotor 41 with which the upper surface of the first outer ring 513 of the first bearing 51 comes into contact and the second rotor 42 with which the lower surface of the second outer ring 523 of the second bearing 52 comes into contact.As a result, a structure is achieved in which the axial gap between the stator 30 and the first magnet 412 fixed to the first rotor 41 and the second magnet 422 fixed to the second rotor 42 can be more accurately and easily adjusted and maintained in a stable state.

[0056] The shim 60 corresponds to a "gap adjustment member." That is, the "gap adjustment member" is one or more shims 60 that are sandwiched and fixed from above and below between the first bearing 51 and the first rotor 41 or between the second bearing 52 and the second rotor 42 in the axial direction. The "gap adjustment member" is also one or more shims 60 that are sandwiched and fixed from above and below between the first bearing 51 and the boss portion 21 of the bush 20 or between the second bearing 52 and the boss portion 21 of the bush 20 in the axial direction. Furthermore, when the "gap adjustment member" is one shim 60, the width of the shim 60 can be finely adjusted by machining, allowing for highly accurate gap adjustment with an axial thickness of a few tenths of a millimeter or less.

[0057] As described above, the "gap adjustment member" is a member that makes it possible to adjust the size of the gap between the stator 30 and the first magnet 412 or the second magnet 422. In other words, the motor 1 further includes a "gap adjustment member" that makes it possible to more accurately and easily adjust the axial distance between the stator 30 and the first magnet 412 or the second magnet 422.

[0058] As shown in Figure 5, after adjusting the axial distance between the stator 30 and the first rotor 41 and the second rotor 42 using the above method, the distance LA between the upper surface of the first outer ring 513 of the first bearing 51 and the lower surface of the second outer ring 523 of the second bearing 52 becomes shorter than the sum LB of the axial length of the boss portion 21 of the bushing 20, the axial length of the first inner ring 511 of the first bearing 51, and the axial length of the second inner ring 521 of the second bearing 52.

[0059] <3. Other Modifications> Although the exemplary embodiment and first modified example of the present invention have been described above, the present invention is not limited to the above embodiment and first modified example. Some of the elements appearing in the above embodiment and first modified example may be deleted or known elements may be added without departing from the spirit of the present invention.

[0060] Furthermore, the detailed shapes of the motor and the traveling vehicle may differ from those shown in the drawings of the above-described embodiment and modified example.

[0061] <4. Summary> The present technology can be configured as follows. (1): a shaft disposed along a central axis extending in the vertical direction; a bushing connected to the shaft radially outward and non-rotatably relative to the shaft, the bushing extending in the up-down direction; a stator fixed radially outward of the bush; a first bearing disposed above the bush; a second bearing disposed below the bush; a first rotor disposed above the stator; a second rotor disposed below the stator; and the first bearing is supported between a lower surface of the first rotor and an upper surface of the bushing; the second bearing is supported between an upper surface of the second rotor and a lower surface of the bushing, the first bearing supports the first rotor so as to be rotatable relative to the shaft; the second bearing supports the second rotor so as to be rotatable relative to the shaft; The motor, wherein the first rotor and the second rotor are fixed to each other in the vertical direction radially outward of the stator.

[0062] (2): The motor according to (1), the first rotor has a first magnet that faces the stator in the vertical direction, the second rotor has a second magnet that faces the stator in the vertical direction.

[0063] (3): The motor according to (1) or (2), the first bearing is a rolling bearing having a first outer ring and a first inner ring that sandwich a first rolling element therebetween in the radial direction, an upper surface of the first outer ring contacts a lower surface of a radially inner end portion of the first rotor; a lower surface of the first inner ring contacts an upper surface of the bushing, the second bearing is a rolling bearing having a second outer ring and a second inner ring that sandwich a second rolling element therebetween in the radial direction, a lower surface of the second outer ring contacts an upper surface of a radially inner end portion of the second rotor, The upper surface of the second inner ring contacts the lower surface of the bushing.

[0064] (4): A motor according to any one of (1) to (3), The bushing is a boss portion extending cylindrically around the shaft in the axial direction; an annular plate portion extending radially outward from the boss portion in an annular plate shape centered on the central axis; Including, The stator is fixed to a radially outer end of the annular plate portion.

[0065] (5): A motor according to any one of (1) to (4), Wiring connected to the stator and The shaft a hollow portion extending inside the shaft in the axial direction and opening to the outer circumferential surface of the shaft; The motor, wherein the wiring is arranged so as to be able to pass through the hollow portion.

[0066] (6): A motor according to any one of (1) to (5), The first rotor is A plurality of first fins are provided at intervals in the circumferential direction and each protrudes upward. A motor having

[0067] (7): A motor according to any one of (1) to (6), The second rotor is A plurality of second fins are provided at intervals in the circumferential direction and each protrude downward. A motor having

[0068] (8): (4) The motor according to the present invention, The distance between the upper surface of the first outer ring and the lower surface of the second outer ring is a motor having an axial length shorter than the sum of the axial length of the boss portion, the axial length of the first inner ring, and the axial length of the second inner ring.

[0069] (9): The motor according to (2), a gap adjusting member that adjusts the axial distance between the stator and the first magnet or the second magnet; a motor further comprising:

[0070] (10): The motor according to (9), The gap adjustment member is one or more shims that are sandwiched and fixed from above and below between the first bearing and the first rotor in the axial direction, or between the second bearing and the second rotor in the axial direction.

[0071] (11): The motor according to (9) or (10), The bushing is a boss portion extending cylindrically around the shaft in the axial direction; an annular plate portion extending radially outward from the boss portion in an annular plate shape centered on the central axis; Including, The gap adjustment member is one or more shims that are sandwiched and fixed from above and below between the first bearing and the boss portion in the axial direction, or between the second bearing and the boss portion in the axial direction.

[0072] (12): A traveling vehicle having the motor according to any one of (1) to (11) and a tire, wherein the rotation of the first rotor and the second rotor is transmitted to the tire, a tire wheel extending radially outward from at least one of the first rotor and the second rotor; and A traveling vehicle, wherein the tire is held on the tire wheel. [Industrial Applicability]

[0073] The present application can be used in motors and vehicles. The motor of the present application can also be used alone in various electrical appliances (e.g., washing machines or electric fans) and testing machines (e.g., centrifuges) that do not have wheels or tires. [Explanation of symbols]

[0074] 1 motor 2 Tire Wheels 3 Tires 10 shaft 15 Wiring 20 Bush 21 Boss Section 22 Annular plate 30 Stator 31 Stator core 41 First Rotor 42 Second rotor 51 First bearing 52 Second bearing 60 Sim 90 center axis 100 cars 411 (first rotor) first rotor yoke 412 First magnet (of first rotor) 413 (First rotor) first flange 414 (First rotor) first adjustment part 415 (First rotor) first fin 421 (second rotor) second rotor yoke 422 (second rotor) second magnet 423 (Second rotor) second flange 424 (second rotor) second adjustment part 425 (second rotor) second fin 511 (First bearing) First inner ring 512 (First bearing) First rolling element 513 (First bearing) First outer ring 521 (2nd bearing) 2nd inner ring 522 (second bearing) second rolling element 523 (Second bearing) second outer ring

Claims

1. a shaft disposed along a central axis extending in the vertical direction; a bushing connected to the shaft radially outward and non-rotatably relative to the shaft, the bushing extending in the up-down direction; a stator fixed radially outward of the bush; a first bearing disposed above the bush; a second bearing disposed below the bush; a first rotor disposed above the stator; a second rotor disposed below the stator; and the first bearing is supported between a lower surface of the first rotor and an upper surface of the bushing; the second bearing is supported between an upper surface of the second rotor and a lower surface of the bushing; the first bearing supports the first rotor so as to be rotatable relative to the shaft; the second bearing supports the second rotor so as to be rotatable relative to the shaft; the first rotor and the second rotor are fixed to each other in the vertical direction radially outward of the stator.

2. 2. The motor according to claim 1, the first rotor has a first magnet that faces the stator in the vertical direction; the second rotor has at least one of a second magnet facing the stator in the vertical direction.

3. 3. The motor according to claim 1 or 2, the first bearing is a rolling bearing having a first outer ring and a first inner ring that sandwich a first rolling element therebetween in the radial direction, an upper surface of the first outer ring contacts a lower surface of a radially inner end portion of the first rotor; a lower surface of the first inner ring contacts an upper surface of the bushing, the second bearing is a rolling bearing having a second outer ring and a second inner ring that sandwich a second rolling element therebetween in the radial direction, a lower surface of the second outer ring contacts an upper surface of a radially inner end portion of the second rotor, The upper surface of the second inner ring contacts the lower surface of the bushing.

4. 4. The motor according to claim 3, The bushing is a boss portion extending cylindrically around the shaft in the axial direction; an annular plate portion extending radially outward from the boss portion in an annular plate shape centered on the central axis; Including, The stator is fixed to a radially outer end of the annular plate portion.

5. 3. The motor according to claim 1 or 2, Wiring connected to the stator and The shaft a hollow portion extending inside the shaft in the axial direction and opening to the outer circumferential surface of the shaft; The motor, wherein the wiring is arranged so as to be able to pass through the hollow portion.

6. 3. The motor according to claim 1 or 2, The first rotor is a plurality of first fins that are spaced apart from one another in the circumferential direction and each protrude upward; A motor having

7. 3. The motor according to claim 1 or 2, The second rotor is a plurality of second fins that are spaced apart from one another in the circumferential direction and each protrude downward; A motor having

8. 5. The motor according to claim 4, The distance between the upper surface of the first outer ring and the lower surface of the second outer ring is a motor having an axial length shorter than the sum of the axial length of the boss portion, the axial length of the first inner ring, and the axial length of the second inner ring.

9. 3. The motor according to claim 2, a gap adjusting member that adjusts the axial distance between the stator and the first magnet or the second magnet; a motor further comprising:

10. 10. The motor according to claim 9, the gap adjustment member is one or more shims that are sandwiched and fixed from above and below between the first bearing and the first rotor, or between the second bearing and the second rotor, in the axial direction.

11. 10. The motor according to claim 9, The bushing is a boss portion extending cylindrically around the shaft in the axial direction; an annular plate portion extending radially outward from the boss portion in an annular plate shape centered on the central axis; Including, the gap adjustment member is one or more shims that are fixed while being sandwiched from above and below between the first bearing and the boss portion in the axial direction, or between the second bearing and the boss portion in the axial direction.

12. A traveling vehicle comprising the motor according to claim 1 or 2 and a tire, wherein rotation of the first rotor and the second rotor is transmitted to the tire, a tire wheel extending radially outward from at least one of the first rotor and the second rotor; and A traveling vehicle, wherein the tire is held on the tire wheel.

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