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 bush is connected to the shaft radially outside the shaft relatively unrotatably with respect to the shaft. A stator is fixed to the bush radially outside the bush. A first rotor is arranged above the stator. A second rotor is arranged below the stator. A first bearing is arranged above the bush. A second bearing is arranged below the bush. A first bearing is supported between an upper surface of the first rotor and a lower surface of a first screw to support the first rotor relatively unrotatably with respect to the shaft. A second bearing is supported between a lower surface of the second rotor and an upper surface of a second screw to support the second rotor relatively unrotatably with respect to the shaft. The first screw and the second screw can move in an axial direction while being screwed with a first thread groove and a second thread groove formed in an outer peripheral surface of the shaft. 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, a second rotor, a first screw, and a second screw. The shaft is arranged along a central axis extending in the vertical direction. The bushing is connected radially outward of the shaft and non-rotatably 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 screw is arranged above the first bearing. The second screw is arranged below the second bearing. A first screw groove is formed at a first position on the outer circumferential surface of the shaft, and the first screw is axially movable while threadedly engaging with the first screw groove. A second screw groove is formed at a second position lower than the first position on the outer circumferential surface of the shaft, and the second screw is axially movable while threadedly engaging with the second screw groove. The first bearing is supported between an upper surface of the first rotor and a lower surface of the first screw. The second bearing is supported between a lower surface of the second rotor and an upper surface of the second screw. 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 up-down direction radially outward of the stator. [Effects of the Invention]

[0007] According to a first exemplary aspect of the present application, the first screw is moved axially while in contact with the upper surface of the first inner ring, and the second screw is moved axially while in contact with the lower surface of the second inner ring, which makes it possible to more accurately and easily adjust the gaps between the first rotor and the second rotor and the stator fixed to the bushing, 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 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, the second bearing, the first screw, and the second screw. [Figure 6] FIG. 6 is a vertical cross-sectional view of a motor and a tire wheel according to the second embodiment. 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 in Figures 1 to 3 and 5 to 6 is defined as "upward" and the left as "downward," and the shapes and positional relationships of each part will be described. However, this definition is not intended to limit the orientation of the motor and traveling vehicle according to the present invention during manufacture and use. In addition, in this application, a "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, a "perpendicular direction" is not limited to being geometrically strictly perpendicular. In other words, it is sufficient that a certain direction and a "perpendicular direction" to that direction are approximately perpendicular to each other to the extent that the effects of the invention are achieved.

[0011] 1. First Embodiment <1-1. Motor and running vehicle configuration> The following describes the configuration of a traveling vehicle 100 including a motor 1 according to a first 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 tire wheel 2 is fastened to the motor 1 with screws 49 (bolts) so that the motor 1 can be separated, whereas in Fig. 2, the motor 1 and 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 Fig. 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, a second bearing 52, a first screw 61, and a second screw 62.

[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. 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 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] A first screw groove 101 is formed on the outer peripheral surface of the shaft 10 at a first position P1, which is above a position where a first bearing 51 (described later) is disposed. A second screw groove 102 is formed on the outer peripheral surface of the shaft 10 at a second position P2, which is below a position where a second bearing 52 (described later) is disposed. In other words, the second position P2 is a position below the first position P1. The first screw groove 101 and the second screw groove 102 are each a helical screw groove (male thread).

[0016] 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.

[0017] 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. Note that, in a later process of assembling the motor 1, retaining rings 151 and 152 are fixed around the shaft 10 above and below the boss portion 21 (see FIG. 5, described later). This prevents the bushing 20, including the boss portion 21, from moving axially.

[0018] 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.

[0019] As shown in the modified example of FIG. 3, the boss portion 21 and the shaft 10 may be formed from a single member. Furthermore, as shown in the modified example of FIG. 3, the shaft 10 may be a hollow shaft. In the modified example of 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 structure, 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.

[0020] 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.

[0021] 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.

[0022] 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.

[0023] 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.

[0024] 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.

[0025] 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.

[0026] 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.

[0027] 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.

[0028] 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.

[0029] 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.

[0030] 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.

[0031] 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.

[0032] The rotor coupling portion 43 extending upward from the second rotor yoke 421 is fixed to the first rotor yoke 411 by fastening screws 48 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.

[0033] 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.

[0034] 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.

[0035] 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 inner ring 511 and the first outer ring 513 that sandwich the first rolling elements 512 therebetween 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.

[0036] 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 inner ring 521 and the second outer ring 523 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 the second rotor 42 can rotate relative to the shaft 10.

[0037] The first screw 61 is disposed above the first bearing 51. The first screw 61 is, for example, a female screw that screws into the first screw groove 101 formed on the outer peripheral surface of the shaft 10. The first screw 61 is capable of moving in the axial direction while screwing into the first screw groove 101. The second screw 62 is disposed below the second bearing 52. The second screw 62 is, for example, a female screw that screws into the second screw groove 102 formed on the outer peripheral surface of the shaft 10. The second screw 62 is capable of moving in the axial direction while screwing into the second screw groove 102.

[0038] 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.

[0039] 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.

[0040] 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.

[0041] 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.

[0042] 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.

[0043] The tire wheel 2 is fixed to the rotor connecting portion 43 by fastening a screw 49 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. It is sufficient that the tire wheel 2 has a structure that extends radially outward from at least one of the first rotor 41 and the second rotor 42 of the motor 1.

[0044] As described above, the tire 3 is held by 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 49, 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.

[0045] 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.

[0046] 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.

[0047] <1-2. 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, the second bearing 52, the first screw 61, and the second screw 62.

[0048] 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 cylindrically upward and downward from the radially inner end of the first rotor yoke 411 around the central axis 90 along the central axis 90. The first adjustment portion 414 extends radially inward from the lower end of the first flange portion 413. Furthermore, the first adjustment portion 414 extends radially outward from the shaft 10 in the circumferential direction around the central axis 90 like an annular plate. The first adjustment portion 414 is located at the radially innermost end of the first rotor 41.

[0049] 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 upper surface of the first adjustment part 414 contacts the lower surface of the first outer ring 513. That is, the lower surface of the first outer ring 513 contacts the upper 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 upper surface of the first inner ring 511 contacts the lower surface of the first screw 61. As a result, the first bearing 51 is supported between the upper surface of the first rotor 41 and the lower surface of the first screw 61. Note that a sufficient gap is provided between the lower surface of the first inner ring 511 and the boss portion 21 so that the first inner ring 511 and the boss portion 21 do not come into contact with each other.

[0050] 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 cylindrically upward and downward from the radially inner end of the second rotor yoke 421 around the central axis 90 along the central axis 90. The second adjustment portion 424 extends radially inward from the upper end of the second flange portion 423. The second adjustment portion 424 also extends radially outward from the shaft 10 in the circumferential direction around the central axis 90 in the shape of an annular plate. The second adjustment portion 424 is located at the radially innermost end of the second rotor 42.

[0051] 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 lower surface of the second adjustment part 424 contacts the upper surface of the second outer ring 523. That is, the upper surface of the second outer ring 523 contacts the lower surface of the radially inner end of the second rotor 42. When the second inner ring 521 of the second bearing 52 is supported on the outer peripheral surface of the shaft 10, the lower surface of the second inner ring 521 contacts the upper surface of the second screw 62. As a result, the second bearing 52 is supported between the lower surface of the second rotor 42 and the upper surface of the second screw 62. A sufficient gap is provided between the upper surface of the second inner ring 521 and the boss portion 21 so that the second inner ring 521 and the boss portion 21 do not come into contact with each other.

[0052] In the first bearing 51 of this embodiment, there is a small gap (hereinafter referred to as an "internal gap") 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 gap. More specifically, in the first bearing 51, the first inner ring 511 can be moved downward relative to the multiple first rolling elements 512, and the first outer ring 513 can be moved upward. This gradually reduces the size of the internal gap.

[0053] During the adjustment stage during assembly of the motor 1, the internal gap of the first bearing 51 can be gradually reduced by moving the first screw 61 downward while in contact with the upper surface of the first inner ring 511. This allows the size of the internal gap to be adjusted. As a result, after the size of the internal gap has been determined, the size of the internal gap is maintained in a stable state even when the motor 1 is running. Note that when the first screw 61 is moved downward, the position of the first outer ring 513 also moves slightly downward.

[0054] Furthermore, as described above, the lower surface of the first outer ring 513 comes into contact with the upper surface of the first adjustment portion 414. As a result, as the first outer ring 513 moves downward, the first rotor 41, including the first adjustment portion 414, also moves slightly downward. Meanwhile, as described above, the bushing 20 and the stator 30 fixed to the bushing 20 are restricted in their axial movement by the retaining rings 151 and 152. This allows only the first rotor 41 to move closer to the stator 30 in the axial direction. As a result, the gap between the stator 30 and the first rotor 41 can be easily adjusted.

[0055] In the second bearing 52 of this embodiment, there is a small gap (internal gap) 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 gap. More specifically, in the second bearing 52, the second inner ring 521 can be moved upward relative to the second rolling elements 522, and the second outer ring 523 can be moved downward. This gradually reduces the size of the internal gap.

[0056] During the adjustment stage during assembly of the motor 1, the internal gap of the second bearing 52 can be gradually reduced by moving the second screw 62 upward while it is in contact with the underside of the second inner ring 521. This allows the size of the internal gap to be adjusted. As a result, after the size of the internal gap has been determined, the size of the internal gap is maintained in a stable state even when the motor 1 is running. Note that when the second screw 62 is moved upward, the position of the second outer ring 523 also moves slightly upward.

[0057] Furthermore, as described above, the upper surface of the second outer ring 523 comes into contact with the lower surface of the second adjustment portion 424. As a result, as the second outer ring 523 moves upward, the second rotor 42, including the second adjustment portion 424, also moves slightly upward. Meanwhile, as described above, the axial movement of the bush 20 and the stator 30 fixed to the bush 20 is restricted by the retaining rings 151 and 152. This allows only the second rotor 42 to approach the stator 30 in the axial direction. As a result, the gap between the stator 30 and the second rotor 42 can be easily adjusted.

[0058] In particular, the components of the motor 1 of this embodiment are designed so that when the first screw 61 is tightened and the stator 30 is moved downward until the internal clearance of the first bearing 51 is approximately zero, and the second screw 62 is tightened and the stator 30 is moved upward until the internal clearance of the second bearing 52 is approximately zero, the clearances between the stator 30 and the first rotor 41 and the second rotor 42 reach desired values. In this way, when the internal clearance of the first bearing 51 becomes approximately zero, the force required for the worker to tighten the first screw 61 increases rapidly, making it easy to determine that the internal clearance has become approximately zero. Furthermore, when the internal clearance of the second bearing 52 becomes approximately zero, the force required for the worker to tighten the second screw 62 increases rapidly, making it easy to determine that the internal clearance has become approximately zero. This allows the worker to easily determine the appropriate adjustment amounts for the first screw 61 and the second screw 62, improving adjustment accuracy.

[0059] As described above, in this embodiment, the first screw 61 is moved in the axial direction while in contact with the upper surface of the first inner ring 511, and the second screw 62 is moved in the axial direction while in contact with the lower surface of the second inner ring 521. This makes it possible to accurately and easily adjust and maintain stable axial gaps between the stator 30, which is fixed to the bushing 20, and the first rotor 41, which is in contact with the lower surface of the first outer ring 513, and the second rotor 42, which is in contact with the upper surface of the second outer ring 523. As a result, it is possible to accurately and easily adjust and maintain stable axial gaps between the stator 30, and the first magnet 412, which is fixed to the first rotor 41, and the second magnet 422, which is fixed to the second rotor 42.

[0060] 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 end of the first outer ring 513 and the lower end of the second outer ring 523 becomes longer than the distance LB between the upper end of the first inner ring 511 and the lower end of the second inner ring 521.

[0061] 2. Second Embodiment Next, the configuration of a traveling vehicle including a motor 1B according to a second embodiment of the present invention will be described. Fig. 6 is a vertical cross-sectional view of the motor 1B and a tire wheel 2B (described later). The following description will focus on configurations that differ from the first embodiment, and redundant description of configurations that are the same as those in the first embodiment will be omitted.

[0062] The motor 1B of this embodiment has a shaft 10B, an upper bushing 221B, a lower bushing 222B, an upper stator 231B, a lower stator 232B, a first rotor 41B, a second rotor 42B, a rotor connection portion 43B, a third rotor 44B, a first bearing 51B, a second bearing 52B, a first screw 61B, and a second screw 62B.

[0063] The shaft 10B is disposed along a central axis 90B extending in the vertical direction. A first screw groove 101B is formed on the outer peripheral surface of the shaft 10B at a first position P1 above the position where the first bearing 51B is disposed. Furthermore, a second screw groove 102B is formed on the outer peripheral surface of the shaft 10B at a second position P2 below the first position P1 and below the position where the second bearing 52B is disposed.

[0064] The upper bush 221B is connected to the shaft 10B radially outward and non-rotatably relative to the shaft 10B. A radially inner portion of the upper bush 221B extends in the vertical direction. An upper stator 231B is fixed to the radially outer side of the upper bush 221B. The lower bush 222B is connected to the shaft 10B radially outward and non-rotatably relative to the shaft 10B below the upper bush 221B. A radially inner portion of the lower bush 222B extends in the vertical direction. A lower stator 232B is fixed to the radially outer side of the lower bush 222B. The upper stator 231B and the lower stator 232B of this embodiment each have a structure equivalent to that of the stator 30 of the first embodiment.

[0065] In a later process of assembling the motor 1B, retaining rings 151B and 152B are fixed around the shaft 10B above the upper bushing 221B and below the lower bushing 222B, respectively, thereby preventing the upper bushing 221B and the lower bushing 222B from moving in the axial direction.

[0066] The first rotor 41B is disposed above the upper stator 231B. The second rotor 42B is disposed below the lower stator 232B. The first rotor 41B, the second rotor 42B, and the rotor coupling portion 43B of this embodiment have the same structures as the first rotor 41, the second rotor 42, and the rotor coupling portion 43 of the first embodiment. Note that in this embodiment, a pair of upper rotor support portions 451B and a lower rotor support portion 452B are further provided radially inward of the rotor coupling portion 43B. The pair of upper rotor support portions 451B and the lower rotor support portion 452B each extend cylindrically around the central axis 90B along the central axis 90B. The upper end portion of the upper rotor support portion 451B is connected to the first rotor 41B. The lower end portion of the lower rotor support portion 452B is connected to the second rotor 42B.

[0067] The third rotor 44B is a rotor of the motor 1B. The third rotor 44B is disposed axially between the upper stator 231B and the lower stator 232B. The third rotor 44B extends in a circular shape in the circumferential direction around the central axis 90B, radially outward of the shaft 10B. The lower end of the upper rotor support portion 451B and the upper end of the lower rotor support portion 452B are connected to the third rotor 44B. The third rotor 44B is fixed at its outer periphery to the rotor coupling portion 43B so as not to rotate relative to the rotor. As a result, the first rotor 41B, the second rotor 42B, and the third rotor 44B are fixed to each other in the vertical direction, radially outward of the upper stator 231B and the lower stator 232B. The axial position of the third rotor 44B relative to the first rotor 41B and the second rotor 42B is determined by the upper rotor support portion 451B and the lower rotor support portion 452B. The third rotor 44B has a third rotor yoke 441B, a third upper magnet 442B, and a third lower magnet 446B.

[0068] Third rotor yoke 441B is a portion that extends in the shape of an annular plate in the circumferential direction about central axis 90B. Third upper magnet 442B is a permanent magnet that is fixed to the upper surface of third rotor yoke 441B at a position facing coil 252B provided on the lower surface of upper stator 231B. Third upper magnet 442B has north and south poles that are alternately arranged at approximately equal angular intervals in the circumferential direction about central axis 90B. Third lower magnet 446B is a permanent magnet that is fixed to the lower surface of third rotor yoke 441B at a position facing coil 253B provided on the upper surface of lower stator 232B. Third lower magnet 446B has north and south poles that are alternately arranged at approximately equal angular intervals in the circumferential direction about central axis 90B.

[0069] The first bearing 51B is disposed above the upper bushing 221B. The first bearing 51B supports the first rotor 41B so as to be rotatable relative to the shaft 10B. The second bearing 52B is disposed below the lower bushing 222B. The second bearing 52B supports the second rotor 42B so as to be rotatable relative to the shaft 10B. The first bearing 51B and the second bearing 52B of this embodiment have the same structures as the first bearing 51 and the second bearing 52 of the first embodiment, respectively.

[0070] The first screw 61B is disposed above the first bearing 51B. The second screw 62B is disposed below the second bearing 52B. The first screw 61B and the second screw 62B of this embodiment have structures equivalent to the first screw 61 and the second screw 62 of the first embodiment, respectively. The first screw 61B is axially movable while threadedly engaging with the first screw groove 101B. The first bearing 51B is supported between the upper surface of the first rotor 41B and the lower surface of the first screw 61B. The second screw 62B is axially movable while threadedly engaging with the second screw groove 102B. The second bearing 52B is supported between the lower surface of the second rotor 42B and the upper surface of the second screw 62B.

[0071] As in the first embodiment, the first screw 61B is moved axially while contacting the upper surface of the first inner ring 511B of the first bearing 51B. This allows the axial gap between the upper stator 231B fixed to the upper bushing 221B and the first rotor 41B, with which the lower surface of the first outer ring 513B of the first bearing 51B comes into contact, to be accurately and easily adjusted and maintained in a stable state. As a result, the axial gap between the upper stator 231B and the first magnet 412B fixed to the first rotor 41B can be accurately and easily adjusted and maintained in a stable state.

[0072] Furthermore, the second screw 62B is moved axially while being in contact with the lower surface of the second inner ring 521B of the second bearing 52B. This allows the axial gap between the lower stator 232B fixed to the lower bushing 222B and the second rotor 42B, with which the upper surface of the second outer ring 523B of the second bearing 52B comes into contact, to be accurately and easily adjusted and maintained in a stable state. As a result, the axial gap between the lower stator 232B and the second magnet 422B fixed to the second rotor 42B can be accurately and easily adjusted and maintained in a stable state.

[0073] When motor 1B is driven, a driving current is supplied via wiring 15B to coils 251B and 252B provided on the upper and lower surfaces of upper stator 231B, and to coils 253B and 254B provided on the upper and lower surfaces of lower stator 232B. This generates a rotating magnetic field in each of coils 251B to 254B. Repeated attraction and repulsion caused by magnetic forces centered around central axis 90B occurs between the stator core of upper stator 231B and first magnet 412B of first rotor 41B and third upper magnet 442B of third rotor 44B, generating circumferential torque in first rotor 41B and third rotor 44B.

[0074] Furthermore, repeated attraction and repulsion caused by magnetic force centered on central axis 90B occurs between the stator core of lower stator 232B and the second magnet 422B of second rotor 42B and the third lower magnet 446B of third rotor 44B, generating circumferential torque in the second rotor 42B and the third rotor 44B. As a result, the first rotor 41B, the second rotor 42B, the rotor coupling portion 43B, the third rotor 44B, and the rotor support portion 45B rotate in the circumferential direction about central axis 90B relative to shaft 10B via the first bearing 51B and the second bearing 52B. In particular, in this embodiment, providing the third rotor 44B in this manner enables a higher output (rotational driving force) to be obtained.

[0075] <3. Other Modifications> Although exemplary embodiments and modifications of the present invention have been described above, the present invention is not limited to the above-described embodiments and modifications. Some of the elements appearing in the above-described embodiments and modifications may be deleted or known elements may be added without departing from the spirit of the present invention.

[0076] 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.

[0077] <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; a first screw disposed above the first bearing; a second screw disposed below the second bearing; and A first screw groove is formed at a first position on the outer circumferential surface of the shaft, and the first screw is movable in the axial direction while threadedly engaging with the first screw groove; A second thread groove is formed at a second position lower than the first position on the outer circumferential surface of the shaft, and the second screw is movable in the axial direction while threadedly engaging with the second thread groove, the first bearing is supported between an upper surface of the first rotor and a lower surface of the first screw; the second bearing is supported between a lower surface of the second rotor and an upper surface of the second screw, 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.

[0078] (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 at least one of a second magnet facing the stator in the vertical direction.

[0079] (3): The motor according to (1) or (2), 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.

[0080] (4): A motor according to any one of (1) to (3), the first bearing is a rolling bearing having a first inner ring and a first outer ring that sandwich a first rolling element therebetween in the radial direction, an upper surface of the first inner ring contacts a lower surface of the first screw; a lower surface of the first outer ring contacts an upper surface of a radially inner end portion of the first rotor, the second bearing is a rolling bearing having a second inner ring and a second outer ring that sandwich a second rolling element therebetween in the radial direction, a lower surface of the second inner ring contacts an upper surface of the second screw, A motor, wherein an upper surface of the second outer ring contacts a lower surface of a radially inner end portion of the second rotor.

[0081] (5): (4) The motor according to the present invention, A motor, wherein the distance between the upper end of the first outer ring and the lower end of the second outer ring is longer than the distance between the upper end of the first inner ring and the lower end of the second inner ring.

[0082] (6): A motor according to any one of (1) to (5), 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.

[0083] (7): a shaft disposed along a central axis extending in the vertical direction; an upper bushing that is connected to the shaft radially outward and non-rotatably relative to the shaft and extends in the up-down direction; a lower bushing that is connected to the shaft radially outwardly below the upper bushing and is non-rotatable relative to the shaft, and that extends in the up-down direction; an upper stator fixed radially outward of the upper bush; a lower stator fixed radially outward of the lower bush; a first bearing disposed above the upper bush; a second bearing disposed below the lower bush; a first rotor disposed above the upper stator; a second rotor disposed below the lower stator; a third rotor disposed axially between the upper stator and the lower stator; a first screw disposed above the first bearing; a second screw disposed below the second bearing; and A first screw groove is formed at a first position on the outer circumferential surface of the shaft, and the first screw is movable in the axial direction while threadedly engaging with the first screw groove; A second thread groove is formed at a second position lower than the first position on the outer circumferential surface of the shaft, and the second screw is movable in the axial direction while threadedly engaging with the second thread groove, the first bearing is supported between an upper surface of the first rotor and a lower surface of the first screw; the second bearing is supported between a lower surface of the second rotor and an upper surface of the second screw, 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, the second rotor, and the third rotor are fixed to one another in the vertical direction radially outward of the upper stator and the lower stator.

[0084] (8): A motor according to any one of (1) to (7), The first rotor is A plurality of first fins are provided at intervals in the circumferential direction and each protrudes upward. A motor having

[0085] (9): A motor according to any one of (1) to (7), The second rotor is A plurality of second fins are provided at intervals in the circumferential direction and each protrude downward. A motor having

[0086] (10): A traveling vehicle having the motor according to any one of (1) to (7) 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]

[0087] 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 that do not have wheels or tires (e.g., washing machines or electric fans) or testing machines (e.g., centrifuges). [Explanation of symbols]

[0088] 1,1B motor 2,2B tire wheel 3 Tires 10,10B shaft 15,15B wiring 20 Bush 21 Boss Section 22 Annular plate 30 Stator 31 Stator core 41,41B First rotor 42,42B Second rotor 44B 3rd rotor 51,51B First bearing 52,52B Second bearing 61,61B First screw 62,62B Second screw 90,90B center axis 100 cars 101,101B First screw groove 102,102B Second screw groove 221B Upper Bush 222B Lower Bush 231B Upper Stator 232B Lower Stator 411 (first rotor) first rotor yoke 412,412B First magnet (first rotor) 413 (First rotor) first flange 414 (First rotor) first adjustment part 415 (First rotor) first fin 421 (second rotor) second rotor yoke 422,422B (second rotor) second magnet 423 (Second rotor) second flange 424 (second rotor) second adjustment part 425 (second rotor) second fin 511,511B (First bearing) First inner ring 512 (First bearing) First rolling element 513,513B (First bearing) First outer ring 521,521B (2nd bearing) 2nd inner ring 522 (second bearing) second rolling element 523,523B (2nd bearing) 2nd 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; a first screw disposed above the first bearing; a second screw disposed below the second bearing; and a first thread groove is formed at a first position on the outer circumferential surface of the shaft, and the first screw is movable in the axial direction while threadedly engaging with the first thread groove; a second thread groove is formed at a second position lower than the first position on the outer circumferential surface of the shaft, and the second screw is movable in the axial direction while threadedly engaging with the second thread groove; the first bearing is supported between an upper surface of the first rotor and a lower surface of the first screw; the second bearing is supported between a lower surface of the second rotor and an upper surface of the second screw; 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 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.

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

5. 5. The motor according to claim 4, A motor, wherein the distance between the upper end of the first outer ring and the lower end of the second outer ring is longer than the distance between the upper end of the first inner ring and the lower end of the second inner ring.

6. 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.

7. a shaft disposed along a central axis extending in the vertical direction; an upper bushing that is connected to the shaft radially outward and non-rotatably relative to the shaft and extends in the up-down direction; a lower bushing that is connected to the shaft radially outwardly below the upper bushing and is non-rotatable relative to the shaft, and that extends in the up-down direction; an upper stator fixed radially outward of the upper bush; a lower stator fixed radially outward of the lower bush; a first bearing disposed above the upper bush; a second bearing disposed below the lower bush; a first rotor disposed above the upper stator; a second rotor disposed below the lower stator; a third rotor disposed axially between the upper stator and the lower stator; a first screw disposed above the first bearing; a second screw disposed below the second bearing; and a first thread groove is formed at a first position on the outer circumferential surface of the shaft, and the first screw is movable in the axial direction while threadedly engaging with the first thread groove; a second thread groove is formed at a second position lower than the first position on the outer circumferential surface of the shaft, and the second screw is movable in the axial direction while threadedly engaging with the second thread groove; the first bearing is supported between an upper surface of the first rotor and a lower surface of the first screw; the second bearing is supported between a lower surface of the second rotor and an upper surface of the second screw; 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, the second rotor, and the third rotor are fixed to one another in the vertical direction radially outward of the upper stator and the lower stator.

8. The motor according to claim 1 or claim 7, 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

9. The motor according to claim 1 or claim 7, 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

10. A traveling vehicle comprising the motor according to claim 1 or claim 7 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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