Motor unit and electric bicycle

Abstract

Provided are a motor unit and an electric bicycle with high assemblability. A motor unit (9) is provided with: a case (2) that includes a first divided body (21) and a second divided body (22); an input shaft (30); an output body (32); a motor (33); a speed reduction mechanism (34); a control board (35); and a rotation detection unit (5). The rotation detection unit (5) includes a rotating body (51) that rotates in conjunction with the input shaft (30), and a detection element (52) that detects the rotation of the rotating body (51). The rotating body (51) and the control board (35) are assembled to the first divided body (21).

Description

Motor units and electric bicycles

[0001] The present disclosure relates to a motor unit and an electric bicycle.

[0002] A known motor unit for use in an electric bicycle includes a case including a first divided body and a second divided body, an input shaft arranged to pass through the case, and a rotation detection unit that detects the rotation of the input shaft.

[0003] In this type of motor unit, Patent Document 1 discloses that the rotating body that constitutes the main part of the rotation detection unit is rotatably supported by a first divided body and a second divided body that is separate from the first divided body.

[0004] Japanese Patent Application Laid-Open No. 2020-79016

[0005] In the conventional motor unit described above, the rotating body had to be supported by the first and second divided bodies, which resulted in poor assembly efficiency (i.e., it was not easy to perform assembly work efficiently).

[0006] The problem that the present disclosure aims to solve is to provide a motor unit and an electric bicycle that are easy to assemble (i.e., that allow assembly work to be performed efficiently).

[0007] A motor unit according to one aspect of the present disclosure is a motor unit for use in an electric bicycle, and includes a case including a first divided body and a second divided body, an input shaft disposed through the first divided body and driven to rotate by human power, an output body outputting the rotation of the input shaft, a motor housed in the case, a speed reduction mechanism housed in the case that reduces the rotation of the motor and transmits it to the output body, a control board that controls the rotation of the motor, and a rotation detection unit that detects the rotation of the input shaft. The rotation detection unit includes a rotating body that rotates in conjunction with the input shaft and a detection element that detects the rotation of the rotating body. The rotating body and the control board are assembled to the first divided body.

[0008] An electric bicycle according to one aspect of the present disclosure includes the motor unit and a wheel to which the rotational force of the motor unit is transmitted.

[0009] FIG. 1 is a schematic side view of an electric bicycle equipped with a motor unit of one embodiment. FIG. 2 is a side view of the motor unit of the same. FIG. 3 is a cross-sectional view taken along line A-A in FIG. 2. FIG. 4 is a perspective view of the motor unit of the same with parts removed. FIG. 5 is a perspective view of the motor unit of the same with further parts removed. FIG. 6 is a side view of the motor unit of the same with further parts removed. FIG. 7 is a cross-sectional view taken along line B-B in FIG. 6. FIG. 8 is a perspective view showing the main parts of the motor unit of the same. FIG. 9 is an exploded perspective view showing the main parts of the same. FIG. 10 is a side view of the first divided body of the motor of the same.

[0010] 1. One embodiment (Overall structure of electric bicycle) The electric bicycle 1 of one embodiment is an electrically assisted bicycle. The electric bicycle 1 of one embodiment includes a frame 10, a motor unit 9 fixed to the frame 10, and two wheels 11 rotatably connected to the frame 10. The two wheels 11 are a front wheel 111 and a rear wheel 112. Of these, the rear wheel 112 is rotated by the driving force output from the motor unit 9.

[0011] The directions of front, rear, left and right used in this disclosure are defined relative to the rider of the electric bicycle 1. In other words, the direction in which the rider rides the electric bicycle 1 is forward, the opposite direction is backward, the direction to the left as seen by the rider is leftward, and the direction to the right as seen by the rider is rightward. Each configuration will be described in detail below.

[0012] As shown in FIG. 1 , the frame 10 has a head pipe 101 , an upper pipe 102 , a lower pipe 103 , a stand pipe 104 , a seat stay 105 , a chain stay 106 , and a bracket 107 .

[0013] The frame 10 (i.e., the above-mentioned components constituting the frame 10) is made of a metal such as aluminum or stainless steel, but may contain a non-metallic material in part. The entire frame 10 may be made of a non-metallic material, and the material of the frame 10 is not particularly limited.

[0014] A handle post 12 is rotatably inserted through the head pipe 101. A front fork 121 is formed at the lower end of the handle post 12. A front wheel 111 is rotatably attached to the front fork 121. A handle bar 122 is fixed to the upper end of the handle post 12.

[0015] The front end of an upper pipe 102 is fixed to the head pipe 101. The rear end of the upper pipe 102 is fixed to a stand pipe 104. A pipe 132 extending downward from the saddle 13 is inserted into the upper end opening of the stand pipe 104. The saddle 13 is fixed by fixing this pipe 132 to the stand pipe 104. A bracket 107 is fixed to the lower end of the stand pipe 104.

[0016] The front end of a lower pipe 103 is further fixed to the head pipe 101. A bracket 107 is fixed to the rear end of the lower pipe 103.

[0017] The motor unit 9 is fixed to the underside of the bracket 107. The front end of the chain stay 106 is fixed to the rear end of the bracket 107.

[0018] The front end of a seat stay 105 is fixed to the rear end of the upper pipe 102. The rear end of the seat stay 105 is connected to the rear end of the chain stay 106, and a rear wheel 112 is rotatably attached to this connected part. A battery 15 for supplying power to the motor unit 9 is detachably attached to the lower pipe 103.

[0019] (Motor unit) As shown in Figures 2 to 4, the motor unit 9 used in the electric bicycle 1 includes a case 2, an input shaft 30, an input body 31, an output body 32, a motor 33, a reduction mechanism 34, and a control board 35.

[0020] The case 2 constitutes a main part of the outer shell of the motor unit 9 in one embodiment. The case 2 has an internal space 20 formed therein.

[0021] The input shaft 30 is disposed so as to penetrate the case 2 in the left-right direction. The left-right direction in this disclosure is the left-right direction as seen by a rider of the electric bicycle 1 to which the motor unit 9 is attached. The input shaft 30 is rotated by human power.

[0022] The input body 31 is housed in the internal space 20 of the case 2. The input body 31 is disposed between the input shaft 30 and the output body 32, and is configured to transmit the rotation of the input shaft 30 to the output body 32.

[0023] A portion of the output body 32 is housed in the internal space 20 of the case 2. The output body 32 is configured to output the rotation of the input shaft 30 transmitted via the input body 31.

[0024] The motor 33 is housed in the internal space 20 of the case 2. The motor 33 is a driving source for driving the wheels 11 of the electric bicycle 1 to rotate.

[0025] The speed reduction mechanism 34 is housed in the internal space 20 of the case 2. The speed reduction mechanism 34 is configured to reduce the rotation of the motor 33 and transmit it to the output body 32.

[0026] The control board 35 is housed in the internal space 20 of the case 2. The control board 35 has a control unit that controls the rotation of the motor 33.

[0027] Furthermore, the motor unit 9 includes a torque detection unit 4 , a rotation detection unit 5 , and a connection structure 6 .

[0028] The torque detection unit 4 is housed in the internal space 20 of the case 2. The torque detection unit 4 is configured to detect the torque acting on the input shaft 30.

[0029] The rotation detection unit 5 is housed in the internal space 20 of the case 2. The rotation detection unit 5 is configured to detect the rotation of the input shaft 30.

[0030] The connection structure 6 is housed in the internal space 20 of the case 2. The connection structure 6 is a structure that electrically connects the torque detection unit 4 and a connector 58 (described later) that is disposed on the control board 35.

[0031] Hereinafter, each component of the motor unit 9 according to one embodiment will be described in more detail.

[0032] (Case) The case 2 includes a first divided body 21 and a second divided body 22. The first divided body 21 constitutes one half of the case 2 in the left-right direction. The second divided body 22 constitutes the other half of the case 2 in the left-right direction.

[0033] The first division 21 and the second division 22 have mating surfaces 213, 223 that abut against each other. The mating surface 213 of the first division 21 is formed along the outer periphery of the opening 210 of the first division 21, over the entire circumference of the opening 210. The mating surface 223 of the second division 22 is formed along the outer periphery of the opening of the second division 22, over the entire circumference of the opening.

[0034] The first divided body 21 and the second divided body 22 are joined to each other, for example, by bolts, with their mating surfaces 213, 223 aligned. The first divided body 21 and the second divided body 22 are joined to each other, thereby forming an internal space 20.

[0035] In one embodiment of the motor unit 9, the case 2 further includes an intermediate body 23 (see FIG. 4 ). The intermediate body 23 is sandwiched between the first divided body 21 and the second divided body 22. In other words, the intermediate body 23 is housed in the internal space 20 formed by the first divided body 21 and the second divided body 22 combined together. The intermediate body 23 is a separate member from the first divided body 21 and the second divided body 22, but may be formed integrally with the first divided body 21 or the second divided body 22.

[0036] The first partition 21 has a through hole 211 through which the input shaft 30 is inserted. The second partition 22 has a through hole 221 through which the input shaft 30 is inserted. The input shaft 30 is disposed so as to penetrate the first partition 21 and the second partition 22 in the left-right direction via the through hole 211 of the first partition 21 and the through hole 221 of the second partition 22.

[0037] 10 and other drawings, the first divided body 21 includes a bottom wall 212 having a through hole 211 formed therein, a peripheral wall 214 protruding in the left-right direction from the outer peripheral edge of the bottom wall 212, and a rib-like wall 215 protruding from the bottom wall 212. A mating surface 213 of the first divided body 21 is formed at the tip of the peripheral wall 214.

[0038] (Wall) The wall 215 protrudes from a portion of the bottom wall 212 surrounding the through hole 211, along the outer periphery of the through hole 211. The direction in which the wall 215 protrudes from the bottom wall 212 is the direction in which the second divided body 22 is positioned relative to the first divided body 21. The wall 215 is formed integrally with the bottom wall 212, but may also be formed separately from the bottom wall 212 (i.e., separately from the first divided body 21).

[0039] Hereinafter, the orientation in which the first divided body 21 is positioned relative to the second divided body 22 will be referred to as the “first orientation.” The orientation in which the second divided body 22 is positioned relative to the first divided body 21 will be referred to as the “second orientation.” The first orientation and the second orientation are opposite to each other.

[0040] The direction in which the wall 215 protrudes from the bottom wall 212 coincides with the direction in which the peripheral wall 214 protrudes from the bottom wall 212. The direction in which the wall 215 and the peripheral wall 214 protrude from the bottom wall 212 is the second direction.

[0041] The protruding tip of wall 215 facing in the second direction is located farther from second divided body 22 in the left-right direction than the protruding tip of peripheral wall 214 facing in the second direction. The protruding tip of wall 215 is located in the first direction than the protruding tip of peripheral wall 214. In other words, the protruding tip of peripheral wall 214 is located in the second direction than the protruding tip of wall 215.

[0042] Wall 215 is formed in an arc shape along a part of the outer periphery of circular through-hole 211. Here, arc shape is not limited to being strictly arc shape, but also includes being approximately arc shape. As will be described later, wall 215 of first divided body 21 is positioned so as to separate rotating body 51 of rotation detection unit 5 and input shaft 30.

[0043] The first divided body 21 further includes a recess 216 formed in the bottom wall 212 and a protrusion 217 formed in the bottom wall 212 .

[0044] (Recess) The recess 216 is formed in a portion surrounding the through-hole 211 of the bottom wall 212. The recess 216 is a blind hole recessed in a first direction. The recess 216 is a circular hole with a bottom. One end of the shaft member 53 (described later) is inserted into the recess 216.

[0045] A wall 215 is located between the recess 216 and the through hole 211. In the radial direction of the through hole 211, the distance between the through hole 211 and the recess 216 is greater than the distance between the through hole 211 and the wall 215.

[0046] The recess 216 is located in a first direction further than the tip of the wall 215. In other words, the wall 215 protrudes further than the recess 216 in a second direction.

[0047] (Protrusion) The protrusion 217 is formed on a portion of the bottom wall 212 surrounding the through-hole 211. The protrusion 217 and the recess 216 are positioned at a distance from each other in the circumferential direction of the through-hole 211.

[0048] The protrusion 217 protrudes in a second direction. The direction in which the protrusion 217 protrudes from the bottom wall 212, the direction in which the wall 215 protrudes from the bottom wall 212, and the direction in which the peripheral wall 214 protrudes from the bottom wall 212 coincide with each other.

[0049] The tip of the protrusion 217 facing in the second direction is located closer to the second divided body 22 in the left-right direction than the tip of the wall 215 facing in the second direction.

[0050] A protrusion 218 and a recess 219 for fixing a connecting fitting 61 (described later) are formed on the tip surface of the protrusion 217. In one embodiment, one recess 219 and two protrusions 218 are formed on the tip surface of the protrusion 217. One recess 219 is located between the two protrusions 218.

[0051] In the radial direction of the through hole 211, the distance between the through hole 211 and the protruding portion 217 is greater than the distance between the through hole 211 and the wall 215. The protruding portion 217 is formed integrally with the wall 215.

[0052] (Input Shaft) The input shaft 30 is inserted through the case 2 and is rotatable about its own axis.

[0053] Crank arms 18 are fixed to both ends of the input shaft 30. Pedals 181 are rotatably attached to the tips of the crank arms 18. The rider can apply manual rotational force to the input shaft 30 by pedaling the pedals 181.

[0054] (Input Body) The input body 31 is disposed within the case 2 along the outer circumferential surface of the input shaft 30. The input body 31 is cylindrical and rotates integrally with the input shaft 30.

[0055] The input body 31 is divided into a first input body 311 and a second input body 312. The first input body 311 is connected to the input shaft 30. The rotational force of the input shaft 30 is transmitted to the first input body 311. The second input body 312 is connected to the first input body 311 and is also connected to the output body 32 via a one-way clutch. The rotational force of the first input body 311 is transmitted to the second input body 312. The rotational force of the second input body 312 is transmitted to the output body 32.

[0056] In the motor unit 9 of one embodiment, the first input body 311 and the second input body 312 are configured as separate bodies, but the first input body 311 and the second input body 312 may be configured as an integrated body.

[0057] (Output Body) The output body 32 is cylindrical and rotatably disposed along the outer circumferential surface of the input shaft 30. One end of the output body 32 passes through the through-hole 221 of the second divided body 22 and protrudes outside the case 2.

[0058] A front sprocket 191 is fixed to a portion of the output body 32 that protrudes from the case 2. The front sprocket 191 rotates integrally with the output body 32. As shown in FIG. 1 , a rear sprocket 192 is fixed to the hub of the rear wheel 112. A chain 193 is wound between the front sprocket 191 and the rear sprocket 192.

[0059] The output body 32 has integrally therewith a driven gear 345 that constitutes the final stage of the reduction mechanism 34. The driven gear 345 protrudes radially outward from the output body 32. The driven gear 345 has a common axis with the input shaft 30, the input body 31, and the output body 32. The diameter of the driven gear 345 is larger than any of the input shaft 30, the input body 31, and the output body 32.

[0060] (Motor) The motor 33 includes a cylindrical motor shaft 331 , a rotor 332 coupled to the motor shaft 331 so as to rotate integrally with the motor shaft 331 , and a cylindrical stator 333 positioned to surround the rotor 332 .

[0061] A recess 2125 for accommodating the motor 33 is formed in the bottom wall 212 of the first divided body 21. The recess 2125 has a shape recessed in a first direction. A stator 333 of the motor 33 is fitted into the recess 2125 of the first divided body 21.

[0062] The motor shaft 331 protrudes from the rotor 332 in a second direction.

[0063] (Reduction Mechanism) The reduction mechanism 34 is configured to reduce the rotation speed of the motor 33 and transmit the reduced speed to the output body 32. The reduction mechanism 34 is a two-stage parallel shaft gear type reduction mechanism. Within the case 2, the motor shaft 331, the reduction shaft 343, and the input shaft 30 are positioned parallel to one another.

[0064] The number of reduction stages of the reduction mechanism 34 in the present disclosure is defined as the number of parts (i.e., reduction sections) in the power transmission path from the motor shaft 331 to the output body 32 where a reduction in the rotation speed is achieved.

[0065] The first-stage reduction gear includes a first-stage drive gear 341 that rotates integrally with the motor shaft 331, and a first-stage driven gear 342 that meshes with the first-stage drive gear 341. The first-stage drive gear 341 is configured with teeth formed on the outer circumferential surface of the metal motor shaft 331. The first-stage drive gear 341 can be formed by cutting or plastic processing the motor shaft 331.

[0066] A reduction shaft 343 is fixed to the inner periphery of the first-stage driven gear 342. One end of the reduction shaft 343 is rotatably supported on the inner surface of the first divided body 21 via a bearing.

[0067] The second-stage reduction gear includes a second-stage drive gear 344 that rotates integrally with the reduction shaft 343, and a second-stage driven gear 345 that meshes with the second-stage drive gear 344. The second-stage driven gear 345 meshes with the second-stage drive gear 344, and thereby receives the rotational driving force of the reduction shaft 343 and rotates. A plurality of teeth that mesh with the second-stage drive gear 344 are formed on the outer circumferential surface of the second-stage driven gear 345.

[0068] The second-stage driven gear 345 constitutes the final stage of the reduction mechanism 34. As described above, the final-stage driven gear 345 of the reduction mechanism 34 is provided on the outer periphery of the output body 32. The final-stage driven gear 345 is formed integrally with the output body 32, but the final-stage driven gear 345 and the output body 32 may be formed separately from each other. In the output body 32, the rotational force of the motor 33, which is reduced in speed and transmitted via the reduction mechanism 34, and the rotational force of the input shaft 30 due to human power are combined.

[0069] (Control Board) The control board 35 is assembled to the first divided body 21. In other words, the control board 35 is fixed to the first divided body 21 and is supported by the first divided body 21. The control board 35 is fixed to the first divided body 21 in a position parallel to the bottom wall 212 of the first divided body 21, for example, using screws.

[0070] The control unit of the control board 35 has, for example, a microcomputer, and controls the operation of each element by executing a program stored in a storage unit such as a ROM (Read Only Memory). Any known control unit can be used as appropriate.

[0071] The control board 35 has a first surface 351 facing the first divided body 21 and a second surface 352 facing the second divided body 22. The first surface 351 and the second surface 352 are flat surfaces facing in opposite directions.

[0072] A connector 58 that is electrically connected to the torque detection unit 4 is disposed on the control board 35. The connector 58 is disposed on the second surface 352 of the control board 35.

[0073] (Torque Detection Unit) The torque detection unit 4 is disposed on the outer periphery of the input body 31. In one embodiment of the motor unit 9, the torque detection unit 4 is a magnetostrictive torque detector. The torque detection unit 4 is configured to detect the torque applied to the input shaft 30.

[0074] 3, 9, etc., the rotation detection unit 5 is provided adjacent to the input shaft 30. The rotation detection unit 5 includes a rotating body 51, a detection element 52, a shaft member 53, and a pressing member 54.

[0075] The rotor 51 is configured to rotate about an axis separate from that of the input shaft 30. The axis of the rotor 51 and the axis of the input shaft 30 are different from each other. The axis of the rotor 51 and the axis of the input shaft 30 are parallel to each other.

[0076] The rotating body 51 is rotatably supported via a shaft member 53. The rotating body 51 is configured to rotate in conjunction with the input shaft 30. The rotating body 51 and the shaft member 53 are assembled to the first divided body 21. In other words, the rotating body 51 is rotatably supported by the first divided body 21. The shaft member 53 is fixed to the first divided body 21 and is also supported by the first divided body 21.

[0077] The rotating body 51 includes a magnet 512 and a second gear 72. When the rotating body 51 rotates in conjunction with the rotation of the input shaft 30, the magnet 512 rotates. The rotation of the magnet 512 is detected by the detection element 52.

[0078] The magnet 512 is, for example, a member in which a magnet is embedded so that its magnetic poles alternate in the circumferential direction, or a magnet that is magnetized so that its magnetic poles alternate in the circumferential direction. The detection element 52 is, for example, a Hall IC (Integrated Circuit) that detects the magnetic force of the magnet 512.

[0079] The second gear 72 meshes with a first gear 71 provided on the outer periphery of the input shaft 30. The first gear 71 rotates integrally with the input shaft 30. In other words, when the input shaft 30 rotates, the rotation of the input shaft 30 is transmitted to the rotating body 51 by the meshing of the first gear 71 and the second gear 72, and the rotating body 51 rotates in conjunction with the input shaft 30.

[0080] The control board 35 is located between the magnet 512 of the rotating body 51 and the second gear 72. The second gear 72 has a larger outer diameter than the magnet 512. The first gear 71 has a larger outer diameter than the second gear 72.

[0081] The detection element 52 is disposed on the control board 35 so as to detect the rotation of the magnet 512 and thereby detect the rotation of the rotating body 51. The detection element 52 of the rotation detection unit 5 is disposed on the first surface 351 of the control board 35 facing the first divided body 21. The control board 35 and the detection element 52 are located between the magnet 512 of the rotating body 51 and the second gear 72.

[0082] The shaft member 53 is a cylindrical member that is inserted into the rotating body 51 to rotatably support the rotating body 51. A first axial end of the shaft member 53 is inserted into the recess 216 of the first divided body 21. As shown in Fig. 3 , the portion of the first divided body 21 where the recess 216 is formed is formed to be thicker than the rest. In other words, the recess 216 is formed in the thick portion of the first divided body 21.

[0083] The pressing member 54 is a metal member. The pressing member 54 is formed by bending a metal plate. As shown in Fig. 9 and other figures, the pressing member 54 includes a portion 541 fixed to the first divided body 21, a portion 542 extending from the portion 541, a hole 543 penetrating the portion 542, and a portion 545 further extending from the portion 542 so as to be folded back.

[0084] Two holes 548 are formed in the portion 541, into which the two protrusions 218 of the protruding portion 217 of the first divided body 21 fit. One hole 549 is formed in the portion 541, which communicates with one recess 219 of the protruding portion 217 of the first divided body 21. A screw, for example, is inserted into the recess 219 of the first divided body 21 through the hole 549 of the pressing member 54.

[0085] A second axial end of the shaft member 53 is inserted into the hole 543 of the portion 542. The portion of the portion 542 where the hole 543 is formed is positioned in a second direction relative to the portion 541.

[0086] The portion 545 is configured by a tip portion of the plate material forming the pressing member 54 that is folded back from the portion 542. The portion 545 is positioned in a second orientation relative to the portion 542. A part of the portion 545 is positioned to overlap the hole 543 when viewed along the axis of the rotating body 51 and the shaft member 53.

[0087] The portion 545 is provided to press the second end of the shaft member 53 and to prevent the rotating body 51 from slipping out of the shaft member 53. The shaft member 53 and the rotating body 51 are rotatably sandwiched between the recess 216 in the bottom wall 212 of the first divided body 21 and the portion 545 of the pressing member 54. That is, in the motor unit 9 of one embodiment, the first divided body 21 and the pressing member 54 cooperate to rotatably support the shaft member 53 and the rotating body 51.

[0088] As described above, the pressing member 54 is assembled to the first divided body 21. In other words, the pressing member 54 is fixed to the first divided body 21 and is supported by the first divided body 21. That is, in the motor unit 9 of one embodiment, the rotating body 51, the shaft member 53, the pressing member 54, and the control board 35 are all assembled to the first divided body 21.

[0089] (Connection Structure) The connection structure 6 is electrically connected to the torque detection unit 4 and also electrically connected to a connector 58 on the control board 35 .

[0090] 6 and 7 , the connection structure 6 includes a connecting fitting 61 electrically connected to the torque detection unit 4 and a cord 63 electrically connected to the connector 58. The connecting fitting 61 and the cord 63 are electrically connected to each other. The torque detection unit 4 and the connector 58 are electrically connected through the connecting fitting 61 and the cord 63.

[0091] The connecting fitting 61 is an L-shaped fitting bent at a right angle. The connecting fitting 61 includes a protruding portion 611 and a connecting end portion 612. The protruding portion 611 is electrically connected to the torque detection unit 4 and protrudes radially outward from the torque detection unit 4 of the input shaft 30. The connecting end portion 612 protrudes from the tip of the protruding portion 611 along the axial center of the input shaft 30. The connecting end portion 612 protrudes from the tip of the protruding portion 611 toward the control board 35.

[0092] The cord 63 is electrically connected to the connection end 612 of the connector 61. The cord 63 is flexible. The cord 63 is drawn out along the axis of the input shaft 30 toward the control board 35. The cord 63 is drawn out beyond the control board 35 in the second direction and electrically connected to the connector 58 mounted on the second surface 352 of the control board 35.

[0093] The connector 58 is electrically connected to the torque detection unit 4 via the above-described connection structure 6, and therefore can be disposed near the input shaft 30. As shown in Fig. 6 , the connector 58 is located inside the outer circumferential edge of the driven gear 345 that forms the final stage of the reduction mechanism 34 when viewed along the axial center of the input shaft 30.

[0094] The connection structure 6 (i.e., the cord 63 and the connecting fitting 61) electrically connected to the connector 58 is also located inside the outer peripheral edge of the driven gear 345 that forms the final stage of the reduction mechanism 34 when viewed along the axis of the input shaft 30.

[0095] In one embodiment of the motor unit 9, the connection structure 6 includes a plurality of connecting fittings 61 and a plurality of cords 63 electrically connected to the plurality of connecting fittings 61. The plurality of connecting fittings 61 are three connecting fittings 61 arranged in parallel to one another. The plurality of cords 63 are three cords 63 electrically connected to the three connecting fittings 61 in a one-to-one relationship.

[0096] (Positional relationship between the rotation detection unit and the wall) As shown in Fig. 3 and other figures, the wall 215 of the first divided body 21 is located between the rotor 51 of the rotation detection unit 5 and the input shaft 30. The wall 215 of the first divided body 21 separates the rotor 51 of the rotation detection unit 5 from the input shaft 30. Therefore, when assembling the rotor 51 to the first divided body 21, the wall 215 serves as a guide for the assembling work of the rotor 51. In addition, the wall 215 prevents the rotor 51 from coming into contact with surrounding components, which could result in damage or the like.

[0097] The wall 215 of the first divided body 21 is located between the magnet 512 of the rotating body 51 of the rotation detection unit 5 and the torque detection unit 4 arranged on the outer periphery of the input shaft 30. The wall 215 of the first divided body 21 separates the magnet 512 of the rotating body 51 from the torque detection unit 4. Therefore, when assembling the rotating body 51 to the first divided body 21, the wall 215 serves as a guide for the assembling work of the rotating body 51. In addition, the wall 215 prevents the rotating body 51 from coming into contact with surrounding components, which could cause damage or the like.

[0098] In one embodiment of the motor unit 9, the wall 215 preferably includes a magnetic material. Specifically, the wall 215 is preferably formed of a magnetic material such as iron, and the surface of the wall 215 is preferably coated with a magnetic material such as iron by, for example, painting. The magnetic material shields the magnetic field lines generated by the magnet 512.

[0099] When the wall 215 includes a magnetic material, the wall 215 of the first divided body 21 is positioned between the magnet 512 of the rotating body 51 and the torque detection unit 4, thereby suppressing the magnetic force of the magnet 512 from affecting the torque detection unit 4. Therefore, it is possible to use a powerful magnet as the magnet 512.

[0100] Next, various modified examples of the motor unit 9 of one embodiment and the electric bicycle 1 equipped with the same will be described. Note that in the various modified examples described below, components similar to those already described will be assigned the same reference numerals and detailed descriptions will be omitted.

[0101] In the motor unit 9 and electric bicycle 1 of one embodiment, the rotation detection unit 5 is configured as a magnetic rotation detector including the magnet 512 and the detection element 52, but the type of the rotation detection unit 5 is not limited to this. For example, the rotation detection unit 5 may be configured as an optical rotation detector.

[0102] In one embodiment of the motor unit 9 and electric bicycle 1, the rotating body 51 is configured to rotate around an axis separate from the input shaft 30, but the configuration of the rotating body 51 is not limited to this and may be configured, for example, to rotate around a common axis with the input shaft 30.

[0103] In the motor unit 9 and electric bicycle 1 of one embodiment, the torque detection unit 4 is configured as a magnetostrictive torque detector, but the configuration of the torque detection unit 4 is not limited to this, and other sensing methods can also be used. Examples of other sensing methods include those using strain sensors or pressure sensors, and mechanical types using torsion bars or potentiometers.

[0104] In one embodiment of the motor unit 9 and electric bicycle 1, the reduction mechanism 34 is a two-stage parallel shaft gear type reduction mechanism, but the configuration of the reduction mechanism 34 is not limited to this and may be, for example, a one-stage reduction mechanism or a three-stage or more reduction mechanism.

[0105] In the motor unit 9 and electric bicycle 1 of one embodiment, the detection element 52 is disposed on the first surface 351 of the control board 35, but the location of the detection element 52 is not limited to this and, for example, the detection element 52 may be disposed on the second surface 352 of the control board 35. The detection element 52 may also be disposed on a member other than the control board 35.

[0106] In one embodiment, the rotating body 51 and the shaft member 53 of the rotation detection unit 5 are formed separately, but the configuration of the rotation detection unit 5 is not limited to this, and for example, the rotating body 51 and the shaft member 53 may be formed integrally.

[0107] In one embodiment of the motor unit 9 and the electric bicycle 1, the wall 215 is formed integrally with the bottom wall 212, but this is not limited thereto, and the wall 215 may be formed separately from the bottom wall 212 and fixed to the bottom wall 212. It is also possible that the first segment 21 does not include the wall 215.

[0108] In one embodiment of the motor unit 9 and electric bicycle 1, the connector 58 is located inside the outer periphery of the driven gear 345, but this is not limited to this, and the connector 58 may also be located outside the outer periphery of the driven gear 345.

[0109] In one embodiment of the motor unit 9 and electric bicycle 1, the connection structure 6 that electrically connects the torque detection unit 4 and the connector 58 includes an L-shaped connecting fitting 61, but the configuration of the connection structure 6 is not limited to this and may be configured with other connection structures.

[0110] 3. Summary As is clear from the above description of one embodiment and various modified examples thereof, the motor unit (9) of the first aspect is a motor unit (9) used in an electric bicycle (1), and includes a case (2) including a first divided body (21) and a second divided body (22), an input shaft (30) disposed to penetrate the first divided body (21) and the second divided body (22) and rotated by human power, an output body (32) that outputs the rotation of the input shaft (30), a motor (33) housed in the case (2), a speed reduction mechanism (34) housed in the case (2) that reduces the rotation of the motor (33) and transmits it to the output body (32), a control board (35) that controls the rotation of the motor (33), and a rotation detection unit (5) that detects the rotation of the input shaft (30). The rotation detection unit (5) includes a rotating body (51) that rotates in conjunction with the input shaft (30) and a detection element (52) that detects the rotation of the rotating body (51). The rotating body (51) and a control board (35) are assembled to the first divided body (21).

[0111] According to this embodiment, when assembling the motor unit (9), it is only necessary to assemble the rotating body (51) and the control board (35) to the first divided body (21), which improves the ease of assembly of the motor unit (9).

[0112] In the motor unit (9) of the second aspect, the detection element (52) of the rotation detection unit (5) in the first aspect is arranged on the control board (35).

[0113] According to this aspect, by assembling the control board (35) to the first divided body (21), the detection element (52) is assembled to the first divided body (21) via the control board (35).

[0114] In the motor unit (9) of the third aspect, in the second aspect, the control board (35) has a first surface (351) facing the first divided body (21) and a second surface (352) facing the second divided body (22). The detection element (52) of the rotation detection unit (5) is arranged on the first surface (351) of the control board (35).

[0115] According to this aspect, the rotating body (51), the detecting element (52), and the control board (35) of the rotation detecting section (5) are compactly assembled on the side of the first divided body (21).

[0116] In the motor unit (9) of a fourth aspect, in any one of the first to third aspects, the rotation detection unit (5) further includes a shaft member (53) that rotatably supports the rotor (51). The shaft member (53) is assembled to the first divided body (21).

[0117] According to this aspect, when assembling the motor unit (9), it is only necessary to assemble the rotating body (51), the shaft member (53), and the control board (35) to the first divided body (21), thereby improving the ease of assembly of the motor unit (9).

[0118] In the motor unit (9) of the fifth aspect, in the fourth aspect, the rotation detection unit (5) further includes a pressing member (54) that rotatably supports the shaft member (53) in cooperation with the first divided body (21). The pressing member (54) is assembled to the first divided body (21).

[0119] According to this aspect, the rotor (51), shaft member (53), pressing member (54), and control board (35) can be assembled to the first divided body (21), which improves the ease of assembly of the motor unit (9).

[0120] In the motor unit (9) of the sixth aspect, in the fifth aspect, the pressing member (54) includes a hole (543) into which the shaft member (53) is inserted and a portion (545) that presses the end of the shaft member (53).

[0121] According to this embodiment, the shaft member (53) can be held by a simple pressing member (54).

[0122] The motor unit (9) of a seventh aspect is any one of the first to sixth aspects, further comprising a first gear (71) provided on the outer periphery of the input shaft (30) so as to rotate integrally with the input shaft (30). The rotating body (51) includes a second gear (72) meshing with the first gear (71).

[0123] According to this aspect, the rotation of the input shaft (30) is transmitted to the rotating body (51) which is separate from the input shaft (30) via the first gear (71) and the second gear (72).

[0124] In the motor unit (9) of the eighth aspect, in any one of the first to seventh aspects, the first divided body (21) includes a wall (215) that separates the rotating body (51) of the rotation detection unit (5) from the input shaft (30).

[0125] According to this aspect, when assembling the motor unit 9, the wall 215 of the first divided body 21 functions as a guide for assembling the rotating body 51 and also functions to protect the rotating body 51. This prevents the rotating body 51 from being damaged and also prevents the rotating body 51 from damaging surrounding components.

[0126] The motor unit (9) of a ninth aspect is any one of the first to seventh aspects, further comprising a torque detection unit (4) that detects the torque of the input shaft (30). The first divided body (21) includes a wall (215) that separates the rotating body (51) of the rotation detection unit (5) from the torque detection unit (4).

[0127] According to this aspect, the wall (215) of the first divided body (21) functions as a guide for assembling the rotating body (51), and also functions to protect the rotating body (51), thereby preventing the rotating body (51) from being damaged and also preventing the rotating body (51) from damaging surrounding components.

[0128] In the motor unit (9) of the tenth aspect, the rotor (51) of the rotation detection unit (5) in the ninth aspect includes a magnet (512), and the wall (215) includes a magnetic material.

[0129] According to this aspect, the wall (215) located between the rotating body (51) including the magnet (512) and the torque detection unit (4) prevents the magnetic force of the magnet (512) from affecting the torque detection unit (4).

[0130] The motor unit (9) of an eleventh aspect is the motor unit (9) of any one of the eighth to tenth aspects, wherein the wall (215) is a rib-shaped wall protruding from the first divided body (21).

[0131] According to this embodiment, the wall (215) can be provided on the first divided body (21) with a simple structure.

[0132] The motor unit (9) of a twelfth aspect is any one of the first to eleventh aspects, further comprising a torque detection unit (4) that detects the torque of the input shaft (30), and a connector (58) that is disposed on the control board (35) and electrically connected to the torque detection unit (4). The reduction mechanism (34) is provided on the outer periphery of the output body (32) and includes a driven gear (345) that forms the final stage of the reduction mechanism (34). When viewed along the axis of the input shaft (30), the connector (58) is located inside the outer periphery of the driven gear (345).

[0133] According to this aspect, the connector (58) is arranged compactly.

[0134] The motor unit (9) of a thirteenth aspect is the twelfth aspect, further comprising a connection structure (6) that electrically connects the torque detection unit (4) and the connector (58). The connection structure (6) includes a connecting fitting (61) that is electrically connected to the torque detection unit (4) and includes a connecting end (612) that protrudes toward the control board (35), and a cord (63) that is electrically connected to the connecting end (612) of the connecting fitting (61) and is drawn toward the control board (35) along the axial center of the input shaft (30).

[0135] According to this aspect, the connector (58) electrically connected to the torque detection unit (4) via the connection structure (6) can be positioned inside the outer periphery of the driven gear (345).

[0136] The electric bicycle (1) of the fourteenth aspect comprises the motor unit (9) of any one of the first to thirteenth aspects and a wheel (11) to which the rotational force of the motor unit (9) is transmitted.

[0137] According to this aspect, when assembling the motor unit (9), it is only necessary to assemble the rotating body (51) and the control board (35) to the first divided body (21), which improves the ease of assembly of the motor unit (9) and the electric bicycle (1) equipped with it.

[0138] REFERENCE SIGNS LIST 1 Electric bicycle 11 Wheel 2 Case 21 First divided body 22 Second divided body 30 Input shaft 31 Input body 32 Output body 33 Motor 34 Reduction mechanism 345 Driven gear 35 Control board 351 First surface 352 Second surface 4 Torque detection unit 5 Rotation detection unit 51 Rotating body 512 Magnet 52 Detection element 53 Shaft member 54 Pressing member 543 Hole 545 Part 58 Connector 6 Connection structure 61 Connection fitting 612 Connection end 63 Cord 71 First gear 72 Second gear 9 Motor unit

Claims

1. A motor unit for use in an electric bicycle, comprising: a case including a first divided body and a second divided body; an input shaft that is arranged passing through the first divided body and the second divided body and is rotated by human power; an output body that outputs the rotation of the input shaft; a motor housed in the case; a speed reduction mechanism that is housed in the case and reduces the rotation of the motor before transmitting it to the output body; a control board that controls the rotation of the motor; and a rotation detection unit that detects the rotation of the input shaft, wherein the rotation detection unit includes a rotating body that rotates in conjunction with the input shaft and a detection element that detects the rotation of the rotating body, and the rotating body and the control board are assembled to the first divided body.

2. The motor unit according to claim 1, wherein the detection element of the rotation detection unit is disposed on the control board.

3. The motor unit of claim 2, wherein the control board has a first surface facing the first divided body and a second surface facing the second divided body, and the detection element of the rotation detection unit is disposed on the first surface of the control board.

4. A motor unit according to any one of claims 1 to 3, wherein the rotation detection unit further includes a shaft member that rotatably supports the rotating body, the shaft member being assembled to the first divided body.

5. The motor unit according to claim 4, wherein the rotation detection section further includes a pressing member that cooperates with the first divided body to rotatably support the shaft member, and the pressing member is assembled to the first divided body.

6. The motor unit according to claim 5, wherein the pressing member includes a hole into which the shaft member is inserted and a portion that presses down the end of the shaft member.

7. A motor unit according to any one of claims 1 to 6, further comprising a first gear provided on the outer periphery of said input shaft so as to rotate integrally with said input shaft, and said rotating body including a second gear meshing with said first gear.

8. A motor unit according to any one of claims 1 to 7, wherein the first divided body includes a wall that separates the rotating body of the rotation detection unit from the input shaft.

9. A motor unit according to any one of claims 1 to 7, further comprising a torque detection unit that detects the torque of the input shaft, and wherein the first divided body includes a wall that separates the rotating body of the rotation detection unit from the torque detection unit.

10. The motor unit according to claim 9, wherein the rotating body of the rotation detection unit includes a magnet, and the wall includes a magnetic material.

11. The motor unit according to any one of claims 8 to 10, wherein the wall is a rib-shaped wall protruding from the first divided body.

12. A motor unit according to any one of claims 1 to 8, further comprising: a torque detection unit that detects the torque of the input shaft; and a connector that is disposed on the control board and electrically connected to the torque detection unit; wherein the reduction mechanism is provided on the outer periphery of the output body and includes a driven gear that forms the final stage of the reduction mechanism; and when viewed along the axis of the input shaft, the connector is located inside the outer periphery of the driven gear.

13. The motor unit of claim 12, further comprising a connection structure that electrically connects the torque detection unit and the connector, the connection structure including: a connecting fitting electrically connected to the torque detection unit and including a connecting end that protrudes toward the control board; and a cord electrically connected to the connecting end of the connecting fitting and drawn toward the control board along the axis of the input shaft.

14. An electric bicycle comprising the motor unit of any one of claims 1 to 13 and a wheel to which the rotational force of the motor unit is transmitted.

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