Wheel hub and electric vehicle

Abstract

A hub configured in the center of a wheel has a hub shaft extending along a center axis, a hub body rotatably configured to the hub shaft, a stator having a coil, a rotor having a rotor shaft extending along the center axis, and a lead wire electrically connected to the coil. The rotor shaft is connected to the hub body. The hub shaft has a through-hole passing through from an end portion on one side in the axial direction to an outer peripheral surface. The through-hole has a first opening portion formed in the outer peripheral surface of the hub shaft. The lead wire is configured in the through-hole. The end portion on one side in the axial direction and the end portion on the other side in the axial direction of the first opening portion are different in position in the circumferential direction with the center axis as a reference.

Description

TECHNICAL FIELD

[0001] The present application relates to a wheel hub configured at the center of a wheel of an electric vehicle, and an electric vehicle provided with the wheel hub. BACKGROUND

[0002] Conventionally, a wheel hub having a rotor and a stator having a coil is known. Such a wheel hub has a wire connected to the coil. Also, the wheel hub has a wheel hub shaft on which a wire passage opening at a front end is formed. The wire is drawn out to the outside from the end of the wheel hub shaft through the wire passage.

[0003] PRIOR ART DOCUMENTS

[0004] PATENT DOCUMENTS

[0005] Patent Document 1: Japanese Laid-Open Publication No. Japanese Patent Application Publication No. 2005-75106 SUMMARY

[0006] PROBLEMS TO BE SOLVED BY THE INVENTION

[0007] In the above-described wheel hub, there is a possibility that the installation of the wire becomes difficult because the wire needs to pass through the wire passage formed along the wheel hub shaft. Also, in the case of a structure in which the wire is drawn out from the end of the wheel hub shaft, the path of the wire becomes long.

[0008] An object of the present application is to provide a wheel hub in which a lead wire can be easily installed.

[0009] MEANS FOR SOLVING THE PROBLEMS

[0010] An exemplary wheel hub of the present application is configured at the center of a wheel. The wheel hub has a wheel hub shaft extending along a center axis and protruding to the outside on one side in the axial direction, a cylindrical wheel hub body rotatably configured to the wheel hub shaft and extending in the axial direction, a stator having a coil formed by winding a wire and configured inside the wheel hub body, a rotor having a rotor shaft extending along the center axis, opposed to the stator in the radial direction or the axial direction, and configured to be rotatable with respect to the stator, and a lead wire electrically connected to the wire. The rotor shaft is connected to the wheel hub body. The wheel hub shaft has a through-hole passing through from the end on the other side in the axial direction to the outer circumferential surface. The through-hole has a first opening portion formed in the outer circumferential surface of the wheel hub shaft, and the lead wire is configured in the through-hole. The end on one side in the axial direction and the end on the other side in the axial direction of the first opening portion are different in position in the circumferential direction with the center axis as a reference.

[0011] EFFECTS OF THE INVENTION

[0012] An exemplary wheel hub of the present application can easily install a lead wire. BRIEF DESCRIPTION OF DRAWINGS

[0013] Figure 1 is a schematic diagram of an electric vehicle of an embodiment of the present application.

[0014] Figure 2 is a perspective view of a hub mounted on a front fork.

[0015] Figure 3 is a sectional view taken along a vertical plane of the hub and viewed from the front.

[0016] Figure 4 is a perspective view viewed from the front lower side of the right hub axle.

[0017] Figure 5 is a perspective view viewed from the front lower side of the right hub axle after the lead wire is removed.

[0018] Figure 6 is a bottom view of the right hub axle.

[0019] Figure 7 is a rear view of the right hub axle.

[0020] Figure 8 is a view viewed from the right side in the direction along the central axis of the right hub axle.

[0021] Figure 9 is a view viewed from the left side in the direction along the central axis of the right hub axle.

[0022] Figure 10 is a perspective view viewed from the front lower side of the right hub axle of the first modified example.

[0023] Figure 11 is a view viewed from the right side in the direction along the central axis of the right hub axle. DETAILED DESCRIPTION

[0024] Hereinafter, exemplary embodiments of the present application will be described in detail with reference to the accompanying drawings. In this specification, in explaining the hub 10, the direction parallel to the central axis J1 of the hub 10 shown in FIG. 1 will be referred to as the "axial direction". In addition, the direction orthogonal to the central axis of each axis that can rotate will be referred to as the "radial direction", and the direction along the circular arc centered on the central axis will be referred to as the "circumferential direction". In addition, taking the state in which the hub 10 is mounted to the electric vehicle 100 as a reference, the advancing direction of the electric vehicle 100 will be set as the "front direction F". In addition, in the direction along the central axis J1 with the hub 10 as the center, one side will be defined as the right direction R, and the other side will be defined as the left direction L. Furthermore, the directions in the following explanation are defined for the sake of convenience of explanation, and sometimes do not coincide with the directions of the hub 10 actually used. Figure 1

[0025] Figure 1 ​is a schematic diagram of an electric vehicle of an embodiment of the present application. In the present embodiment, the electric vehicle 100 is an electrically assisted bicycle that assists the force of a user stepping on a pedal 106. As shown in Figure 1 , the electric vehicle 100 has a vehicle body 101, two wheels 102, a power transmission mechanism 103, and a power supply portion 104.

[0026] The vehicle body 101 includes a handlebar 107 and a seat 108. The two wheels 102, the power transmission mechanism 103, and the power supply portion 104 are mounted on the vehicle body 101. The two wheels 102 are mounted as front wheels 102f at the front of the vehicle body 101 and as rear wheels 102r at the rear. The power transmission mechanism 103 is connected to the rear wheels 102r. In addition, a hub 10 is disposed at the center of the front wheels 102f.

[0027] The power transmission mechanism 103 includes a crank 105 mounted on a crank shaft 105a and the pedal 106. In addition, the power transmission mechanism 103 also includes a drive gear, a driven gear mounted on the rear wheels 102r, and a chain linking the drive gear and the driven gear (none of which is shown). The crank 105 is fixed to the crank shaft 105a rotatably mounted on the vehicle body 101. And, the pedal 106 is rotatably mounted at the front end of the crank 105.

[0028] The power supply portion 104 is mounted on the vehicle body 101. The power supply portion 104 is, for example, a battery, as shown in Figure 1 , which is built in the vehicle body 101. However, it is not limited thereto, and a structure in which it is mounted on the vehicle body 101 and can supply power to the hub 10 can be widely adopted.

[0029] In the electric vehicle 100, a user seated on the seat 108 steps on the pedal 106 to apply a torque to the crank shaft 105a. The torque applied to the crank shaft 105a is transmitted to the rear wheels 102r via the power transmission mechanism 103. The rear wheels 102r rotate by the transmitted torque, and thus the electric vehicle 100 travels.

[0030] In the electric vehicle 100, the hub 10 is mounted on the lower end portion of a front fork Fk that is a part of the vehicle body 101 (see Figure 2 , described later). The front fork Fk has a hub mounting portion Fk1 of a concave shape that is open downward at the lower end. The hub 10 has the second shaft portion 112 of the hub shaft 11, described later, which protrudes to both ends, disposed on the hub mounting portion Fk1. Then, a nut Nt is mounted on and fastened to an external thread (not shown) formed on the outer circumferential surface of the second shaft portion 112. Thus, the hub 10 is mounted on the front fork Fk (see Figure 2 , described later).

[0031] Figure 2 is a perspective view of the hub 10 mounted on the front fork Fk.Figure 3 is a cross-sectional view taken along a vertical plane of the hub 10 and viewed from the front F.

[0032] The hub 10 is disposed in the center of the front wheel 102f and is connected to a circular rim Rm (refer to Figure 1 ) included in the front wheel 102f via spokes Sp (refer to Figure 1 ). In the hub 10, a motor portion 20 housed inside is driven by supply of electric power. The front wheel 102f is driven by the torque of the motor portion 20. That is, in the present embodiment, the hub 10 is a drive device of the electric vehicle 100.

[0033] In addition, the hub 10 is not limited to the front wheel 102f and can be disposed in the rear wheel 102r, or can be disposed in both the front wheel 102f and the rear wheel 102r. That is, the hub 10 is disposed in the center of the wheel 102.

[0034] The hub 10 has a hub shaft 11, a hub body 12, the motor portion 20, and a reduction mechanism 30. In the hub 10, the hub shaft 11 protrudes to the right R and the left L in the axial direction.

[0035] The motor portion 20 is a brushless motor of a direct current. The motor portion 20 is driven by electric power from a power supply portion 104. The motor portion 20 has a stator 21 and a rotor 25. A part of the stator 21 and the rotor 25 is disposed inside a housing 50. The motor portion 20 is an inner rotor type motor in which the rotor 25 is disposed on the radially inner side of the stator 21. In addition, the motor portion 20 is not limited to the inner rotor type motor and can be an outer rotor type motor. In addition, it can be a so-called axial gap motor in which the stator and the rotor are disposed in opposition to each other in the axial direction.

[0036] The stator 21 has a stator core 22, a coil 23, and an insulator 24. The stator 21 is held by the housing 50. The stator core 22 has a core back 221 and a plurality of teeth 222. The core back 221 is circular ring-shaped. The radially outer side surface of the core back 221 is fixed to the housing 50. The teeth 222 protrude in the direction approaching the center axis J1 from the radially inner side surface of the core back 221. The plurality of teeth 222 are disposed at equal intervals in the circumferential direction. The insulator 24 covers at least the teeth 222. The insulator 24 has insulating properties. The coil 23 is formed by winding a wire on the teeth 222 covered by the insulator 24. That is, the stator 21 has the coil 23 formed by winding the wire.

[0037] The rotor 25 has a rotor shaft 26, a rotor core 27, and a rotor magnet 28. The rotor shaft 26 is substantially cylindrical. As Figure 3As shown, the rotor shaft 26 extends along the central axis J1. That is, the motor unit 20 has a rotor 25 with a rotor shaft 26 extending along the central axis J1, which is radially opposed to the stator 21 and configured to be rotatable relative to the stator 21. The rotor shaft 26 is rotatable about the central axis J1.

[0038] The rotor shaft 26 is rotatably supported on the housing 50 by shaft bearings 261. The shaft bearings 261 are located at two axially separated points, rotatably supporting the rotor shaft 26 at these two axially separated points. Here, the shaft bearings 261 are ball bearings, but are not limited to this. Bearing structures capable of smoothly and accurately supporting the rotor shaft 26 can be widely used.

[0039] The rotor 25 is fixed to the outer periphery of the rotor shaft 26. The rotor 25 has a rotor core 27 and a rotor magnet 28. The rotor 25 rotates about a central axis J1 extending in the horizontal direction.

[0040] The rotor core 27 is formed by stacking thin sheet-like electromagnetic steel plates. The rotor core 27 is a cylinder extending axially. Alternatively, the rotor core 27 can be formed by sintering magnetic powder. Multiple rotor magnets 28 are fixed on the rotor core 27. The multiple rotor magnets 28 arrange their magnetic poles alternately along the circumference.

[0041] like Figure 2 , Figure 3 As shown, the housing 50 is cylindrical. The housing 50 has a first housing portion 51 and a second housing portion 52. The first housing portion 51 is a bottomed cylindrical shape with a bottom 511 on the right side R in the axial direction, and has an opening on the left side L. In other words, it has an opening facing to the left L. The second housing portion 52 is a bottomed cylindrical shape with a bottom 521 on the left side L in the axial direction, and has an opening on the right side R. In other words, it has an opening facing to the right R.

[0042] The opening of the first housing portion 51 holds the axial right end of the stator 21. The opening of the second housing portion 52 holds the axial left end of the stator 21. The first housing portion 51 and the second housing portion 52 are axially separated. More specifically, the first housing portion 51 and the second housing portion 52 are axially separated and mounted on the stator 21.

[0043] To further explain, the rotor shaft 26 is rotatably supported on the bottom 511 of the first housing portion 51 and the bottom 521 of the second housing portion 52 via a shaft bearing 261. Furthermore, the axially leftward (L) end of the rotor shaft 26 is formed through a through hole 522 in the bottom 521 of the second housing portion 52. Additionally, the sun gear portion 31 of the reduction mechanism 30, described later, is disposed on the portion of the rotor shaft 26 that protrudes further to the left (L) than the bottom 521 of the second housing portion 52.

[0044] Auxiliary equipment such as a busbar 29 is installed at the right end R of the motor section 20. The busbar 29 is a conductive component that is connected to the wires of the coil 23. A lead wire 40 is connected to the busbar 29. Current is supplied from the power supply section 104 to the coil 23 via the lead wire 40 and the busbar 29. That is, the lead wire 40 is electrically connected to the wires of the coil 23.

[0045] The motor unit 20 is driven by electricity supplied from the power supply unit 104. Specifically, the coil 23 is energized by supplying current from the power supply unit 104 to the coil 23. This energization of the coil 23 generates a magnetic force between it and the rotor magnet 28 of the rotor 25. By energizing the multiple coils 23 at appropriate times, a circumferential torque centered on the central axis J1 is generated on the rotor 25. This torque causes the rotor shaft 26 to rotate about the central axis J1.

[0046] like Figure 3 As shown, the reduction mechanism 30 includes a sun gear section 31, a planetary gear section 32, an internal gear section 33, and a torque limiter 34. The reduction mechanism 30 uses a so-called planetary gear mechanism to reduce the rotation of the rotor shaft 26 and transmit it to the hub body 12.

[0047] like Figures 3 to 5 As shown, the sun gear portion 31 is disposed at the left-hand end L of the rotor shaft 26 in the axial direction. The sun gear portion 31 rotates integrally with the rotor shaft 26. Therefore, the sun gear portion 31 can be formed as a single component with the rotor shaft 26, or it can be mounted on the rotor shaft 26 and fixed by methods such as bonding, welding, threading, riveting, or pressing. Alternatively, other fixing methods can also be used. Furthermore, besides these, fixing methods that allow the sun gear portion 31 to be fixed in a manner that allows it to rotate integrally with the rotor shaft 26 can be widely employed.

[0048] like Figure 3 As shown, the reduction mechanism 30 has a plurality of planetary gear sections 32. The number of planetary gear sections 32 can be three or four, but is not limited to this. The plurality of planetary gear sections 32 are arranged circumferentially. Furthermore, the plurality of planetary gear sections 32 are arranged at equal intervals in the circumferential direction. The planetary gear sections 32 mesh with the sun gear section 31. In this embodiment, the reduction mechanism 30 has three planetary gear sections 32, but is not limited to three. It is sufficient to have two or more planetary gear sections 32. Furthermore, the circumferential arrangement of the planetary gear sections 32 is not limited to equal intervals. That is, the plurality of planetary gear sections 32 mesh with the sun gear section 31 and are arranged circumferentially.

[0049] The planetary gear section 32 is further described. The planetary gear section 32 has a first planetary gear 321 and a second planetary gear 322. In more detail, the planetary gear section 32 has a planetary shaft 320, the first planetary gear 321, and the second planetary gear 322. The planetary shaft 320 extends along a planetary axis J2 that is parallel to the central axis J1. As shown in FIG. 2, the right end portion of the planetary shaft 320 in the axial direction is fixed to the bottom portion 521 of the second housing section 52. In addition, the upper end portion of the planetary shaft 320 is fixed to the left hub shaft 11L. That is, the position of the planetary gear section 32 with respect to the central axis J1 of the planetary axis J2 is fixed. Figure 3

[0050] The first planetary gear 321 and the second planetary gear 322 are rotatably supported on the planetary shaft 320. In addition, the first planetary gear 321 and the second planetary gear 322 are coupled in the axial direction. The second planetary gear 322 rotates integrally with the first planetary gear 321. That is, the planetary gear section 32 is a two-stage gear. However, the planetary gear section 32 is not limited to a two-stage gear. The planetary gear section 32 can be a multi-stage gear of three stages or more, or can be a structure in which only a single gear having a predetermined number of teeth is provided. In addition, the first planetary gear 321 and the second planetary gear 322 can be formed of a single member, or can be coupled in the axial direction and fixed by an adhesive, welding, screw fastening, or the like.

[0051] The ring gear section 33 is a ring-shaped gear. An inner tooth is formed on the radially inner side surface. The ring gear section 33 is engaged with the second planetary gear 322 of the planetary gear section 32. The ring gear section 33 is a cylindrical shape, and a torque limiter 34 is provided at the end portion in the left direction L in the axial direction. The torque limiter 34 is in contact with the inner peripheral surface of the ring gear section 33.

[0052] The torque limiter 34 has a torque limiter outer ring 341 and a torque limiter inner ring 342. The torque limiter outer ring 341 rotates integrally with the ring gear section 33 about the central axis J1. The torque limiter inner ring 342 rotates integrally with the hub cover section 122 of the hub body 12. In addition, in the torque limiter 34, when the torque limiter inner ring 342 rotates in the rotation direction Rt of the front wheel 102f, the rotation of the torque limiter outer ring 341 is transmitted to the torque limiter inner ring 342.

[0053] In addition, in the hub 10 of the present embodiment, a planetary gear mechanism is employed as the reduction mechanism 30, but is not limited thereto. A structure that can reduce the rotation of the motor section 20 can be widely employed. In addition, the rotor shaft 26 of the motor section 20 can be directly connected or connected via the torque limiter to the hub body 12. The rotor shaft 26 is directly or indirectly connected to the hub body 12. That is, the rotor shaft 26 is connected to the hub body 12.

[0054] ​The hub 10 has two hub axles 11. In the following description, the hub axle 11 on the right (R) will be divided into a right hub axle 11R, and the hub axle 11 on the left will be divided into a left hub axle 11L, as needed. The center of each hub axle 11 coincides with the central axis J1. That is, the hub axle 11R extends along the central axis J1 and protrudes outward on one side of the axial direction.

[0055] First, the common structure of the right wheel hub axle 11R and the left wheel hub axle 11L will be explained.

[0056] The hub shaft 11 has a first shaft portion 111, a second shaft portion 112, and a flange portion 113. The first shaft portion 111 is cylindrical with a central shaft J1 as its center and extends along the central shaft J1. That is, the hub shaft 11R has a cylindrical first shaft portion 111 extending along the central shaft J1.

[0057] The second shaft portion 112 is cylindrical, centered on the central axis J1. The outer diameter of the second shaft portion 112 is smaller than the outer diameter of the first shaft portion 111. Furthermore, the second shaft portion 112 extends from one side of the first shaft portion 111 along the direction of the central axis J1, i.e. Figure 3 The hub shaft 11R extends along the outer end face of the central shaft J1. That is, the hub shaft 11R has a cylindrical second shaft portion 112 that protrudes from one axial side of the first shaft portion 111 in the direction along the central shaft J1 and has a smaller diameter than the first shaft portion 111. An external thread (not shown) is formed on the outer peripheral surface of the second shaft portion 112.

[0058] The flange portion 113 extends from the other side of the first shaft portion 111 along the central axis J1, i.e. Figure 3 The flange 113 extends radially outward along the outer periphery of the central axis J1. The flange 113 is annular. The motor part 20 is fixed to the flange 113.

[0059] Both the right wheel hub axle 11R and the left wheel hub axle 11L have the aforementioned structure. Furthermore, while the right wheel hub axle 11R and the left wheel hub axle 11L are integrally formed, they are not limited to this and can also be formed in parts. For example, the second shaft portion 112 can be formed as a cylinder, and the first shaft portion 111 can be fixed by pressing or other fixing methods. Alternatively, other structures are also possible. In the wheel hub 10, the centers of both the right wheel hub axle 11R and the left wheel hub axle 11L are aligned with the central axis J1. In other words, the right wheel hub axle 11R and the left wheel hub axle 11L have the same central axis J1 and are separately arranged in the direction of the central axis J1.

[0060] The flange portion 13 of the right hub shaft 11R is fixed to the bottom portion 511 of the first housing portion 51. In addition, the flange portion 13 of the left hub shaft 11L is fixed to the bottom portion 521 of the second housing portion 52 via the planetary shaft 320. Thus, the stator 21 of the motor portion 20 is fixed to the hub shaft 11.

[0061] Next, the structure included only in the right hub shaft 11R will be described. The hub 10 has a lead wire 40 that connects the motor portion 20 housed inside and a control portion not shown disposed outside. As shown in Figure 3 In the hub 10, the lead wire 40 is drawn out to the outside from the right side of the hub 10, that is, the right hub shaft 11R. In addition, in the hub 10 of the present embodiment, the structure in which the lead wire 40 is drawn out from the right side, but is not limited thereto, and the structure in which the lead wire 40 is drawn out from the left side can be adopted. In this case, the right hub shaft 11R and the left hub shaft 11L are interchanged.

[0062] Figure 4 is a perspective view of the right hub shaft 11R as viewed from the lower front side. Figure 5 is a perspective view of the right hub shaft 11R as viewed from the lower front side after the lead wire is detached. Figure 6 is a bottom view of the right hub shaft 11R. Figure 7 is a rear view of the right hub shaft 11R. Figure 8 is a view as viewed from the right side in the direction along the center axis J1 of the right hub shaft 11R. Figure 9 is a view as viewed from the left side in the direction along the center axis J1 of the right hub shaft 11R. In addition, in Figure 8 , a portion of the front fork Fk is indicated by a single-dot chain line.

[0063] As shown in Figures 5 to 7 and the like, the right hub shaft 11R has a through-hole 114 and a first protruding portion 115. The first protruding portion 115 protrudes to the right from the right end portion of the first shaft portion 111. In addition, as shown in Figure 5 , the first protruding portion 115 is connected to the outer peripheral surface of the second shaft portion 112. That is, the first protruding portion 115 is disposed on the radially outer peripheral side of the second shaft portion 112, protruding from the end portion of the first shaft portion 111 on the one side in the axial direction. The first protruding portion 115 of the present embodiment is formed of a single member together with the first shaft portion 111 and the second shaft portion 112. In addition, the first protruding portion 115 can be formed separately from the first shaft portion 111 or the second shaft portion 112, and fixed by a fixing method such as welding, screw fastening, or the like.

[0064] The through-hole 114 penetrates from the end portion on the left side in the direction along the center axis J1 of the right hub shaft 11R toward the outer peripheral surface. That is, the hub shaft 11R has the through-hole 114 that penetrates from the end portion on the other side in the axial direction to the outer peripheral surface. In the hub 10, the lead wire 40 is disposed in the through-hole 114.

[0065] Both ends of the through-hole 114 have a first opening portion 116 and a second opening portion 117 at both ends in the axial direction. That is, the through-hole 114 has the first opening portion 116 formed in the outer circumferential surface of the hub shaft 11R.

[0066] As shown in FIG. 1, the first opening portion 116 is formed in the outer circumferential surface of the first shaft portion 111, the right end surface of the spindle J1, and the outer circumferential surface of the second shaft portion 112. That is, a part of the first opening portion 116 is formed in the outer circumferential surface of the first shaft portion 111 and the outer circumferential surface of the second shaft portion 112 and the outer surface of the first protruding portion 115. Figures 5 to 7 By the right hub shaft 11R having the first protruding portion 115, it is possible to improve the rigidity of the right hub shaft 11R. In addition, since the first protruding portion 115 is attached in contact with the fork Fk, it is possible to suppress the positional deviation of the hub 10 with respect to the fork Fk. In addition, since the first opening portion 116 is formed in the first protruding portion 115, it is possible to lengthen the through-hole 114, and it is possible to stably hold the lead wire 40.

[0067] As shown in FIG. 1, the end portion 1162 on the right R and the end portion 1163 on the left L in the circumferential direction of the first opening portion 116 differ in position in the direction of the central axis J1. That is, the end portion 1162 on one side in the axial direction of the first opening portion 116 differs in position from the end portion 1163 on the other side in the axial direction in the circumferential direction with the central axis J1 as a reference.

[0068] Figure 6 By being thus configured, it is possible to form the first opening portion 116 larger than in the case where the lead wire 40 is formed to be drawn out in the axial direction. Thereby, the drawing-out of the lead wire 40 becomes easy. In addition, since the first opening portion 116 is made large, the movable region of the lead wire 40 becomes large, so the handling of the drawn-out lead wire 40 becomes easy. Thereby, it is possible to mount the hub 10 on a fork Fk of a different shape.

[0069] In addition, as shown in FIG. 1, the first protruding portion 115 is disposed behind the first opening portion 116 in the rotation direction Rt of the wheel 102f. In the hub 10, the hub body 12 is rotated in the rotation direction Rt by the torque output from the motor portion 20. At this time, a reaction force in the direction opposite to the rotation direction Rt acts on the right hub shaft 11R.

[0070] In addition, as shown in FIG. 1, the first protruding portion 115 is disposed behind the first opening portion 116 in the rotation direction Rt of the wheel 102f. In the hub 10, the hub body 12 is rotated in the rotation direction Rt by the torque output from the motor portion 20. At this time, a reaction force in the direction opposite to the rotation direction Rt acts on the right hub shaft 11R. Figure 8

[0071] ​​At this time, the first protruding portion 115 of the right hub shaft 11R is pushed against the hub mounting portion Fk1 of the fork Fk. By the right hub shaft 11R having the first protruding portion 115, the rigidity of the portion of the right hub shaft 11R that contacts the hub mounting portion Fk1 can be increased. Thus, the reaction force at the time of rotation of the wheel 102f can be received, and the right hub shaft 11R can be securely fixed to the fork Fk.

[0072] If further explained, as shown in Figure 8 a portion of the first opening portion 116 is formed on the end portion of the first shaft portion 111 on the one side in the axial direction, and the portion of the first opening portion 116 formed on the first shaft portion 111 has a curved portion 1161 that curves the periphery outward. In this way, by having the curved portion 1161, when the lead wire 40 contacts the curved portion 1161 of the first opening portion 116, the lead wire 40 is less likely to be damaged.

[0073] The through-hole 114 has the first opening portion 116 and the second opening portion 117 at both ends. The second opening portion 117 is formed on the end portion of the flange portion 113 on the left side L in the axial direction. That is, the through-hole 114 has the second opening portion 117 that opens on the other side in the axial direction of the hub shaft 11R.

[0074] Also, as shown in Figure 8 from the direction along the center axis J1, the first opening portion 116 has a portion that overlaps the second opening portion 117 in the axial direction. By being configured in this way, when the lead wire 40 is routed in the through-hole 114, the lead wire 40 can be confirmed and routed. Thus, the lead wire 40 can be reliably routed in the through-hole 114.

[0075] As shown in Figure 9 the second opening portion 117 is disposed radially offset with respect to the center axis J1. In other words, from the direction of the center axis J1, the center of the second opening portion 11 is different from the position of the center axis J1. By being configured in this way, it is easy to connect the lead wire 40 to the bus bar 29 that connects the lead wire 40 and the coil 23 disposed on the radially outer side of the rotor shaft 26. Thus, the manufacturing of the hub 10 becomes easy.

[0076] In addition, a portion of the first opening portion 116 is formed on the outer peripheral surface of the first shaft portion 111. Also, the length L1 from the end portion on the one side in the axial direction of the first opening portion 116 formed on the outer peripheral surface of the first shaft portion 111 to the end portion on the other side in the axial direction can also be shorter than the axial length L2 of the first protruding portion 115.

[0077] By lengthening the axial length L2 of the first protruding portion 115, the guidance of the lead wire 40 can be lengthened. Thus, the lead wire 40 can be stably routed along the right hub shaft 11R.

[0078] The hub body 12 is rotatably supported to the hub shaft 11 via the hub bearing Br. The hub body 12 is rotatably arranged to the hub shaft 11 and is a cylindrical shape extending in the axial direction. The hub body 12 has a housing portion 121 and a hub body cover portion 122. The housing portion 121 is a bottomed cylindrical shape extending along the center axis J1.

[0079] The housing portion 121 has a hub body cylinder portion 123 and a hub body bottom portion 124. The hub body cylinder portion 123 is a cylindrical shape centered on the center axis J1. The hub body bottom portion 124 extends to the radially inner side from the right end of the hub body cylinder portion 123 in the direction of the center axis J1. A bottom portion through-hole 125 that penetrates in the axial direction is formed in the radially central portion of the hub body bottom portion 124. The right hub shaft 11R penetrates the bottom portion through-hole 125. The hub body bottom portion 124 is rotatably supported to the right hub shaft 11R via the hub bearing Br.

[0080] In addition, the housing portion 121 has two hub flange portions 126 that extend to the radially outer side from the outer peripheral surface. The two hub flange portions 126 are arranged separately in the axial direction. The hub flange portions 126 have spoke holes 127 for inserting the spokes Sp.

[0081] The hub body cover portion 122 is fixed to the end portion of the hub body cylinder portion 123 in the axial direction left L of the housing portion 121. The hub body cover portion 122 is arranged in opposition to the hub body bottom portion 124 of the housing portion 121 in the axial direction. By fixing the hub body cover portion 122 to the hub body cylinder portion 123, the internal space 120 of the hub body 12 is formed.

[0082] The motor portion 20 and the reduction mechanism 30 are housed in the internal space 120. That is, the stator 21 is arranged inside the hub body 12. Furthermore, the fixing of the hub body cover portion 122 to the hub body cylinder portion 123 is performed, for example, by threaded fastening. However, it is not limited thereto, and press-fitting, adhesion, welding, or the like can be employed as the fixing method. In addition to these, a method that can firmly fix the hub body cover portion 122 to the hub body cylinder portion 123 can be widely employed.

[0083] The hub body cover portion 122 is rotatably supported to the left hub shaft 11L via the hub bearing Br.

[0084] The coil 23 of the motor portion 20 arranged inside the hub body 12 is connected to the lead wire 40 via the bus bar 29. Current is supplied to the coil 23 via the lead wire 40. Thereby, the coil 23 is excited. Thereby, a magnetic force is generated between the excited coil 23 and the rotor magnet 28. By generating this magnetic force at an appropriate timing, the rotor 25 rotates.

[0085] The rotor 25 is rotated, and thereby the rotor shaft 26 is rotated. The rotation of the rotor shaft 26 is transmitted to the sun gear portion 31. The rotation of the sun gear portion 31 is transmitted to the planetary gear portion 32, and from the planetary gear portion 32 to the ring gear portion 33. Thereby, the ring gear portion 33 is rotated. The ring gear portion 33 is connected to the hub cover portion 122 of the hub body 12 via the torque limiter 34. When the ring gear portion 33 is rotated in the rotation direction Rt (refer to FIG. 1), the rotation of the ring gear portion 33 is transmitted to the hub cover portion 122. The hub body 12 is rotated with respect to the hub shaft 11. And, via the spokes Sp mounted on the hub flange portion 126 of the hub body 12, the rim Rm is rotated, and the tire Ty mounted on the rim Rm is rolled on the ground, thereby driving the electric vehicle 100. Figure 8 ) is rotated, the rotation of the ring gear portion 33 is transmitted to the hub cover portion 122. The hub body 12 is rotated with respect to the hub shaft 11. And, via the spokes Sp mounted on the hub flange portion 126 of the hub body 12, the rim Rm is rotated, and the tire Ty mounted on the rim Rm is rolled on the ground, thereby driving the electric vehicle 100.

[0086] Thus, by adopting the structure in which the stator 21 and the rotor 25 are housed inside the hub 10, as compared with the structure in which the electric drive portion that drives or assists the driving of the power transmission mechanism 103 is provided, the structure can be simplified. In addition, the motor portion 20 is provided inside the hub 10. Therefore, the electric drive portion can be mounted on the fork Fk, and the versatility of the electric drive portion can be improved.

[0087] Figure 10 is a perspective view of the right hub shaft 11R2 of the first modified example as viewed from the lower front of the right hub shaft 11R2. Figure 11 is a view as viewed from the right side in the direction along the center axis J1 of the right hub shaft 11R2. The right hub shaft 11R2 of the present modified example is different from the right hub shaft 11R illustrated in FIGS. 1 to 4 in that the right hub shaft 11R2 has the first protruding portion 115 and the second protruding portion 118. The points other than this are the same as the structure of the right hub shaft 11R. Therefore, in the right hub shaft 11R2, the same symbols are attached to the structures substantially the same as the right hub shaft 11R, and the detailed explanation is omitted. Figure 6 、 Figure 8 Thus, by adopting the structure in which the stator 21 and the rotor 25 are housed inside the hub 10, as compared with the structure in which the electric drive portion that drives or assists the driving of the power transmission mechanism 103 is provided, the structure can be simplified. In addition, the motor portion 20 is provided inside the hub 10. Therefore, the electric drive portion can be mounted on the fork Fk, and the versatility of the electric drive portion can be improved.

[0088] The right hub shaft 11R2 has the second protruding portion 118 disposed in front of the first opening portion 116 in the rotation direction Rt of the wheel 102f. Further, the circumferential width on the outer peripheral surface of the second protruding portion 118 is narrower than the circumferential width on the outer peripheral surface of the first protruding portion 115.

[0089] By thus configuring, by making the circumferential width of the first protruding portion 115 wider than the circumferential width of the second protruding portion 118, it is possible to improve the rigidity of the right hub shaft 11R2 while securing the size of the first opening portion 116. In addition, since the lead wire 40 is held by the first protruding portion 115 and the second protruding portion 118, it is possible to stably hold the lead wire 40.

[0090] Further, the first protruding portion 115 has a first flat surface 1151 on the rear side in the rotation direction Rt of the wheel 102f. The second protruding portion 118 has a second flat surface 1181 on the front side in the rotation direction Rt of the wheel 102f. Also, the first flat surface 1151 and the second flat surface 1181 can be parallel to each other.

[0091] When the right hub shaft 11R2 is installed on the hub mounting portion Fk1 of the fork Fk, the rotation of the right hub shaft 11R2 is suppressed. Thereby, the lead wire 40 can be positioned on the hub mounting portion Fk1. Thereby, the lead wire 40 can be routed in the correct position with respect to the fork Fk.

[0092] Further, in the above-described embodiment, a so-called electric power-assisted bicycle having the power transmission mechanism 103 other than the hub 10 is employed, but is not limited thereto. For example, it can be an electric vehicle in which only the hub 10 is used as a power source.

[0093] In the above-described embodiment, the hub in which the motor portion 20 is used as a power source by supplying current from the power supply portion 104 to the coil 23 is described, but is not limited thereto. For example, a hub having a power generation mechanism that rotates the rotor 25 by the rotation of the wheel 102f to generate power by the coil 23 can be formed in the same structure as the hub having the above-described power source.

[0094] The various technical features disclosed in this specification can be variously changed within the scope of the gist of the technical creation. In addition, the plurality of embodiments and modified examples shown in this specification can be implemented in combination within a possible range.

[0095] The present application can be applied to, for example, an electric power-assisted bicycle, an electric scooter, an electric wheelchair, and the like, which are electric vehicles that obtain driving force by electric power. In addition, it can be used for a hub for power generation used for a bicycle and the like.

[0096] Explanation of Symbols

[0097] 100 - electric vehicle, 101 - vehicle body, 102 - wheel, 102f - front wheel, 102r - rear wheel, 103 - power transmission mechanism, 104 - power supply section, 105 - crank, 105a - crank shaft, 106 - pedal, 107 - handle, 108 - seat, 10 - wheel hub, 11 - wheel hub shaft, 11L - left wheel hub shaft, 11R - right wheel hub shaft, 111 - first shaft portion, 112 - second shaft portion, 113 - flange portion, 114 - through hole, 115 - first protruding portion, 1151 - first flat surface, 116 - first opening portion, 117 - second opening portion, 11R2 - right wheel hub shaft, 118 - second protruding portion, 1181 - second flat surface, 12 - wheel hub body, 120 - internal space, 121 - housing portion, 122 - wheel hub body cover portion, 123 - wheel hub body cylinder portion, 124 - wheel hub body bottom portion, 125 - bottom portion through hole, 126 - wheel hub flange portion, 127 - spoke hole, 13 - flange portion, 20 - motor section, 21 - stator, 22 - stator core, 221 - core back portion, 222 - tooth, 23 - coil, 24 - insulator, 25 - rotor, 26 - rotor shaft, 261 - shaft bearing, 262 - tooth, 27 - rotor core, 28 - rotor magnet, 29 - bus bar, 30 - reduction mechanism, 31 - sun gear portion, 32 - planetary gear portion, 320 - planetary shaft, 321 - first planetary gear, 322 - second planetary gear, 33 - internally toothed gear portion, 34 - torque limiter, 341 - torque limiter outer ring, 342 - torque limiter inner ring, 40 - lead wire, 50 - housing, 51 - first housing portion, 511 - bottom portion, 52 - second housing portion, 521 - bottom portion, 522 - through hole, Fk - fork, Fk1 - wheel hub mounting portion, J1 - center shaft, J2 - planetary shaft, Nt - nut, Rm - rim, Rt - rotation direction, Sp - spoke, Ty - tire.

Claims

1. A wheel hub, disposed at the center of a wheel, characterized in that, have: The hub axle extends along the central axis and protrudes outward on one side of the axial direction; A cylindrical hub body, which is rotatably mounted on the aforementioned hub shaft and extends axially; The stator has a coil formed by winding wire and is disposed inside the hub body; A rotor having a rotor shaft extending along the aforementioned central axis, positioned radially or axially opposite the aforementioned stator, and configured to rotate relative to the aforementioned stator; and The lead wire is electrically connected to the aforementioned conductor. The rotor shaft is connected to the hub body. The aforementioned hub shaft has a through hole extending from one end on the opposite axial side to the outer peripheral surface. The aforementioned through hole has a first opening formed on the outer peripheral surface of the aforementioned hub shaft, and the aforementioned lead wire is disposed in the aforementioned through hole. The circumferential positions of the ends on one side and the other side of the first opening relative to the central axis are different.

2. The wheel hub according to claim 1, characterized in that, The above-mentioned hub axle has: A columnar first axial portion that extends along the aforementioned central axis; A columnar second shaft portion, which protrudes from one end of the first shaft portion along the central axis, and has a smaller diameter than the first shaft portion; and The first protrusion protrudes axially from one end of the first shaft portion and is disposed radially outward of the second shaft. A portion of the first opening is formed on the outer peripheral surface of the first shaft portion, the outer peripheral surface of the second shaft portion, and the outer surface of the first protrusion.

3. The wheel hub according to claim 2, characterized in that, The first protrusion is positioned behind the first opening in the direction of rotation of the wheel.

4. The wheel hub according to claim 3, characterized in that, It has a second protrusion positioned in front of the first opening in the direction of rotation of the wheel. The circumferential width on the outer peripheral surface of the second protrusion is narrower than the circumferential width on the outer peripheral surface of the first protrusion.

5. The wheel hub according to claim 4, characterized in that, The aforementioned first protrusion has a first plane on the rear side in the direction of rotation of the aforementioned wheel. The aforementioned second protrusion has a second plane on the front side in the direction of rotation of the aforementioned wheel. The first plane and the second plane are parallel.

6. The wheel hub according to any one of claims 1 to 5, characterized in that, A portion of the aforementioned first opening is formed at one end of the aforementioned first shaft portion on one axial side. The periphery of the portion of the first opening formed on the first shaft portion bends outward.

7. The wheel hub according to any one of claims 2 to 5, characterized in that, The aforementioned through hole has a second opening that opens to the other axial side of the aforementioned hub shaft. Viewed from the direction along the central axis, the first opening has a portion that overlaps with the second opening in the axial direction.

8. The wheel hub according to claim 7, characterized in that, The second opening is radially offset relative to the central axis.

9. The wheel hub according to any one of claims 2 to 5, characterized in that, A portion of the aforementioned first opening is formed on the outer peripheral surface of the aforementioned first shaft portion. The length from one end of the first opening formed on the outer peripheral surface of the first shaft portion to the other end is shorter than the axial length of the first protrusion.

10. The wheel hub according to any one of claims 1 to 5, characterized in that, Current is supplied to the coil via the aforementioned leads.

11. An electric vehicle, characterized in that, have: The wheel hub according to any one of claims 1 to 10; and A power supply unit that supplies current to the aforementioned coil.

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