Electric bicycle motor unit

Abstract

To provide a motor unit which is easily assembled, and to provide an electric bicycle.SOLUTION: A motor unit 3 includes a case 4, a motor 5, an output body 8, a speed reduction mechanism 9, and a retainer 38. The motor 5 has a rotor 52 and a stator 53, and the stator 53 is housed in a motor housing space 430 in the case 4. The output body 8 is disposed so as to be rotatable around an axis 60. The speed reduction mechanism 9 is housed in the case 4 and reduces a speed of rotation of the motor 5 to transmit the rotation to the output body 8. The retainer 38 is housed in the case 4 and has a bearing 932 supporting a rotary shaft 90 of a gear included in the speed reduction mechanism 9. At least a part of the retainer 38 overlaps with at least a part of the motor 5 when viewed from an axis 60 direction.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention provides For electric bicycles Motor Unit to More specifically, the present invention relates to a motor having a case, a motor, an output body, and a reduction mechanism. For electric bicycles Motor Unit to Regarding. [Background technology]

[0002] Conventionally, power-assisted bicycles equipped with a human-powered drive system and an electric-powered drive system have been known (see, for example, Patent Document 1). The power-assisted bicycle disclosed in Patent Document 1 includes a case divided into two parts, a left and a right, a motor, and a reduction mechanism. The reduction mechanism includes a reduction shaft, the left end of which is formed with a primary large gear that meshes with a small gear attached to the rotating shaft of the motor, and the right end of which is formed with a secondary small gear that meshes with the secondary large gear and transmits power to the crank sprocket and rear wheel. The reduction shaft is supported by bearings attached to each of the two divided cases. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 9-66882 Summary of the Invention [Problem to be solved by the invention]

[0004] In the power-assisted bicycles described above, the bearings supporting the reduction shaft of the reduction mechanism are attached to each of the two halves of the case, which means that the reduction shaft cannot be secured in place until the two halves of the case are closed, making assembly complicated.

[0005] The present invention has been invented in view of the above-mentioned conventional problems, and is easy to assemble. For electric bicycles Motor Unit to The purpose is to provide [Means for solving the problem]

[0006] In order to solve the above problem, one embodiment of the present invention For electric bicycles The motor unit includes a case, a motor, an output body, a reduction mechanism, and a control board having a control unit for controlling the motor; and a retainer. The motor has a rotor and a stator, and the stator is housed in the motor housing space in the case. The output body is arranged to be rotatable around an axis. The reduction mechanism is housed in the case and reduces the rotation of the motor before transmitting it to the output body. The retainer is housed in the case and has a bearing that supports a rotation shaft of a gear in the reduction mechanism. At least a portion of the retainer overlaps with at least a portion of the motor when viewed in the axial direction. The retainer has a partition wall that separates the speed reduction mechanism and the control board. [Effects of the Invention]

[0008] According to one aspect For electric bicycles Motor Unit to In this case, For electric bicycles Motor Unit to Easy to assemble. [Brief explanation of the drawings]

[0009] [Figure 1] FIG. 1 is a side view of an electric bicycle according to a first embodiment. [Figure 2] FIG. 2 is a cross-sectional view taken along a plane passing through the axes of the input shaft of the motor unit, the rotating shaft of the motor, and the rotating transmission shaft of the reduction gear mechanism of the electric bicycle. [Figure 3] FIG. 3 is a cross-sectional view taken along a plane passing through the axes of the input shaft of the motor unit, the rotation shaft of the motor, and the rotation transmission shaft of the reduction mechanism according to the second embodiment. [Figure 4] FIG. 4 is an exploded perspective view of the motor unit, mainly showing the first divided body and components on the first divided body side. [Figure 5] FIG. 5 is an exploded perspective view of the motor unit, mainly showing the second divided body and components on the second divided body side. [Figure 6]6A and 6B are side views of the motor unit of the same with the second divided body removed, and side views of the same with some members including the second divided body removed. DETAILED DESCRIPTION OF THE INVENTION

[0010] A first embodiment of a motor unit and an electric bicycle according to the present disclosure will be described below with reference to FIGS.

[0011] As shown in Figure 1, the electric bicycle 1 includes a frame 10, a wheel 11, and a motor unit 3. The electric bicycle 1 has a predetermined direction of travel due to its design. In the following description, the direction of travel is referred to as the forward direction, and the opposite direction is referred to as the rearward direction. Furthermore, left and right refer to the left and right when facing forward.

[0012] The frame 10 supports a person (hereinafter referred to as a rider) who rides the electric bicycle 1. The weight of the frame 10 and the rider is supported on the ground via a front wheel 111 and a rear wheel 112 that constitute the wheels 11.

[0013] The frame 10 has a head pipe 101, an upper pipe 102, a lower pipe 103, a vertical pipe 104, a seat stay 105, a chain stay 106, and a bracket 2. The frame 10 is made of a metal such as aluminum or stainless steel, but may contain a non-metallic material in part. Furthermore, the entire frame 10 may be made of a non-metallic material, and the material of the frame 10 is not particularly limited.

[0014] The head pipe 101 is a cylindrical member that opens generally in the vertical direction. Note that "generally vertical direction" here means a direction that forms an angle of approximately 30 degrees or less with the vertical direction. The handle post 12 is inserted into the head pipe 101 so as to penetrate from top to bottom. The handle post 12 is inserted into the head pipe 101 so as to be rotatable around its axial direction. 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. The handle bar 122 is provided with a hand operation unit for turning the electric power on and off, and a gear change operation unit for changing the speed using a gear change mechanism of the rear wheel 112.

[0015] The upper pipe 102 is a cylindrical member that extends generally rearward from the head pipe 101. The upper pipe 102 does not necessarily have to be straight. Note that generally rearward here means a direction that forms an angle of approximately 40 degrees or less with the rear. The front end of the upper pipe 102 is fixed to the rear side wall of the head pipe 101 by welding or the like. The rear end of the upper pipe 102 is fixed to the stand pipe 104.

[0016] The stand pipe 104 is a cylindrical member that opens generally in the vertical direction. The rear end of the upper pipe 102 is fixed to the front side wall near the upper end of the stand pipe 104 by welding or the like. A shaft extending downward from the saddle 13 is inserted into the opening at the upper end of the stand pipe 104. The saddle 13 is fixed to the stand pipe 104 by fixing this shaft to the stand pipe 104. The bracket 2 is fixed to the lower end of the stand pipe 104.

[0017] The lower pipe 103 is a cylindrical member that extends obliquely downward generally rearward from the head pipe 101. The upper pipe 102 does not necessarily have to be straight. Note that "obliquely downward generally rearward" here means a direction that is lower than the rear and that extends downward than the direction in which the head pipe 101 extends. The front end of the lower pipe 103 is fixed, by welding or the like, to a portion of the rear side wall of the head pipe 101 that is lower than the portion to which the upper pipe 102 is fixed. A bracket 2 is fixed to the rear end of the lower pipe 103.

[0018] The bracket 2 is part of the frame 10 and supports the motor unit 3. When viewed from the left and right, the bracket 2 has a shape in which the middle part in the front-to-rear direction is curved upward more than both end parts, but the shape is not limited and it may be formed linearly in the front-to-rear direction. The motor unit 3 is fixed to the underside of the bracket 2 and is supported by the bracket 2. The motor unit 3 is fixed to the bracket 2 with fastening members 14 consisting of bolts or bolt-nuts.

[0019] The front ends of the seat stays 105 are fixed to the rear end of the upper pipe 102 by fitting (including shrink fitting), fastening, welding, or the like. The seat stays 105 are two hollow or solid members that extend roughly rearward from near the upper end of the stand pipe 104. In the first embodiment, the front ends of the cylindrical seat stays 105 are fixed by welding or the like. The rear ends of the seat stays 105 are fixed to the rear ends of the chain stays 106, and the rear wheel 112 is rotatably attached to this part.

[0020] In addition, the bracket 2 and the lower pipe 103 have a battery mounting portion to which a battery 15 for supplying power to the motor unit 3 is mounted.

[0021] Furthermore, the shift wires and brake wires that connect the shift operation unit and the shift mechanism are passed through the lower pipe 103 and the wiring space.

[0022] The motor unit 3 will be described below with reference to Fig. 2 etc. The motor unit 3 includes a case 4, a motor 5, an input shaft 6, an input body 7, an output body 8, and a reduction mechanism 9.

[0023] The case 4 forms the outer shell of the motor unit 3. The case 4 houses devices such as the reduction gear mechanism 9 in an accommodation space formed inside. The case 4 is mainly made of a metal such as aluminum or stainless steel, but a non-metal may also be used, and the material of the case 4 is not particularly limited.

[0024] The case 4 is divided into a first divided body 41 located on the left side and a second divided body 42 located on the right side. The first divided body 41 and the second divided body 42 are combined to form the case 4.

[0025] The first divided body 41 has an internal storage space that opens to the right. The first divided body 41 also has a motor housing section 43 that houses the motor 5. The motor housing section 43 protrudes leftward from the portion of the first divided body 41 other than the motor housing section 43 and has a motor housing space 430 that houses the motor 5 inside. The motor housing space 430 is part of the storage space inside the case 4. In this embodiment, the motor housing space 430 does not straddle the first divided body 41 and the second divided body 42 but is formed integrally with the first divided body 41. However, it may be formed integrally with the second divided body 42. The motor housing section 43 is part of the first divided body 41 and is formed integrally with the portion of the first divided body 41 other than the motor housing section 43. The motor housing space 430 is located on the opposite side (left side in FIG. 2 ) of the case 4 in the direction of the axis 60 from the side where a sprocket 191 (described later) is located (right side in FIG. 2 ). It is preferable that the motor accommodating space 430 is located inside the case 4 on the side opposite the sprocket 191 in the direction of the axis 60 (on the left side in FIG. 2).

[0026] A step portion 433 is formed on an inner surface 431 of the motor accommodating portion 43 that faces the motor accommodating space 430, with the diameter decreasing toward a back wall surface 432 of the motor accommodating portion 43 that faces the motor accommodating space 430 and the diameter increasing away from the back wall surface 432. The formation of such a step portion 433 facilitates positioning of the stator 53. Furthermore, when inserting the stator 53 into the motor accommodating space 430, the inner diameter of the motor accommodating space 430 is large on the near side, making it easy to insert the stator 53.

[0027] The second divided body 42 has an internal storage space that is open to the left. The first divided body 41 and the second divided body 42 are fitted together from the left and right via a gasket 40 so that their respective storage spaces are continuous, and are fixed to each other with fastening members 44 consisting of bolts. The case 4 is formed by fixing the first divided body 41 and the second divided body 42 to each other. The size, shape, thickness, etc. of the case 4 are not particularly limited. The storage space formed inside the case 4 may or may not be sealed.

[0028] The motor unit 3 includes a retainer 38. The retainer 38 is housed in the case 4. The retainer 38 has a holding portion that holds a bearing 932 that supports a rotating shaft 90 of a gear of the reduction gear mechanism 9. When viewed in the direction of the axis 60, at least a portion of the retainer 38 overlaps with at least a portion of the motor 5. When viewed in the direction of the axis 60, the retainer 38 has a region that overlaps with an inner region surrounded by the outer periphery of the stator 53. When viewed in the direction of the axis 60, the area of ​​the overlapping region is preferably 10% to 80% of the area of ​​the inner region surrounded by the outer periphery of the stator 53. This ratio can be changed as appropriate, and is more preferably 10% to 60%, even more preferably 10% to 40%, and even more preferably 10% to 20%. By setting this ratio to 10% or more, the strength of the retainer 38 can be maintained. Furthermore, the smaller this ratio, the lighter the retainer 38 and the lighter the motor unit 3 can be. Incidentally, overlapping when viewed in the direction of the axis 60 does not refer only to the area that overlaps with the axis 60 in the direction of the axis 60 .

[0029] The retainer 38 is made of aluminum or an aluminum alloy. This makes it easier to reduce the weight of the motor unit 3 compared to when the retainer 38 is made of steel or an iron-based metal. The retainer 38 may also be made of a magnesium alloy, an iron-based metal, or a resin. When the retainer 38 is made of an iron-based metal, it is possible to reduce processing costs by forming the retainer 38 by pressing a metal plate. When the retainer 38 is made of resin, it is possible to improve strength by using a carbon-mixed resin (carbon fiber) or a resin containing reinforced fibers. When the retainer 38 is made of resin, it is easier to reduce the weight of the motor unit 3 and the manufacturing costs compared to when the retainer 38 is made of metal.

[0030] The retainer 38 is attached to the case 4 on the side of the case 4 in the direction of the axis 60 where the motor accommodating space 430 is located. The retainer 38 is attached to the first divided body 41. The retainer 38 is attached in contact with the first divided body 41 by fasteners such as screws, by fitting, or the like. Note that "in contact" means that no other member is interposed between the members at the location where they are attached by fasteners, fitting, or the like. By attaching the retainer 38 to the case 4 on the side where the motor accommodating space 430 is located, at least a portion of the retainer 38 is likely to overlap with at least a portion of the motor 5 when viewed from the direction of the axis 60. By overlapping at least a portion of the retainer 38 with at least a portion of the motor 5, it is possible to prevent oil adhering to a rotating shaft 51 (described below) of the motor 5 from scattering and adhering to the motor 5, and to prevent the motor 5 from shifting in the axial direction of the rotating shaft 51. If retainer 38 is made of a material with good thermal conductivity, such as metal, and is connected to control board 35 and motor 5, it will be easier to dissipate heat from control board 35 and motor 5. The greater the proportion of the area within the outer diameter of motor 5, as viewed from the direction of axis 60, that overlaps with retainer 38, the greater the effect of preventing splashed oil from adhering to motor 5 and the greater the effect of heat dissipation.

[0031] The retainer 38 has a through hole 381 through which the rotating shaft 51 of the motor 5 passes. The retainer 38 also has a through hole 382 through which the stator 53 of the motor 5 passes. A bearing 932 is fitted into a portion of the through hole 382. The through hole 382 functions as a holding portion that holds the bearing 932. In this embodiment, the retainer 38 is formed with the through hole 382 to fit the bearing 932. However, the retainer 38 may have a non-through hole formed therein and the bearing 932 may be fitted into this hole, or the bearing 932 may be brought into contact with the stator 53. Note that a contactable portion where the retainer 38 and the stator 53 overlap may be provided when viewed in the radial direction of the input shaft 6. The retainer 38 and the stator 53 may be fitted together at the contactable portion, for example, so that they are always in contact with each other, or they may come into contact when the stator 53 rotates. The contact between the retainer 38 and the stator 53 at the contactable portion prevents rotation of the stator 53. The contactable portion may be formed in the through hole 382, ​​or may be formed in another portion of the retainer 38.

[0032] Furthermore, the retainer 38 may have openings or cutouts in addition to the through holes 381, 382. The retainer 38 may have a plurality of openings or cutouts. Providing the openings or cutouts reduces the weight of the motor unit 3. The openings or cutouts of the retainer 38 may be formed radially from the rotating shaft 51 of the motor 5, or the retainer 38 may be formed in a porous net or mesh shape.

[0033] Furthermore, at least a portion of the retainer 38 may be located between the reduction mechanism 9 and the control board 35. In this embodiment, the retainer 38 has a partition wall 383 that separates the space in which the reduction mechanism 9 is located from the space in which the control board 35 is located. This prevents grease or lubricating oil used in the reduction mechanism 9 from scattering and adhering to the control board 35.

[0034] The motor 5 is attached to the case 4. The motor 5 includes a rotating shaft 51, a rotor 52 that rotates integrally with the rotating shaft 51, and a stator 53. While the motor 5 in this embodiment is an inner rotor type, the motor 5 may be an outer rotor type, a radial gap type, or an axial gap type. The rotor 52, the stator 53, and a portion of the rotating shaft 51 are located within the motor accommodating space 430. The rotating shaft 51 is rotatably accommodated with its axis oriented in the left-right direction. The rotating shaft 51 protrudes from the stator 53 to one side (the right side in the first embodiment), and teeth 54 that mesh with the reduction gear mechanism 9 are formed on the outer surface of the protruding portion. The right end of the rotating shaft 51 is supported by a rotating shaft support bearing 551 disposed in the second divided body 42. The left end of the rotating shaft 51 does not particularly protrude beyond the stator 53 and is supported by a rotating shaft support bearing 552 disposed in the motor accommodating section 43. Since the left and right ends of the rotary shaft 51 are supported by the rotary shaft support bearings 551 and 552, the meshing between the reduction gear mechanism 9 and the teeth 54 is improved.

[0035] The input shaft 6 penetrates the case 4 in the direction of the axis 60, is arranged to be rotatable about the axis 60 of the input shaft 6, and is capable of transmitting rotational force to the output body 8. In the first embodiment, the input shaft 6 is a cylindrical shaft made of a hollow member, but may also be made of a solid member.

[0036] The case 4 has a first bearing 45, which rotatably supports the input shaft 6, at one end side in the direction of the axis 60 (the left end side in the first embodiment). An input shaft hole 411 through which the input shaft 6 passes is formed in the first divided body 41, and the first bearing 45 is disposed in this input shaft hole 411. In the first embodiment, the first bearing 45 is configured by a ball bearing. Note that the first bearing 45 is not limited to a ball bearing and various other bearings, such as a roller bearing, can also be used.

[0037] A seal member 371 made of an O-ring is disposed between the first bearing 45 and the first divided body 41. By disposing the seal member 371, it becomes difficult for the grease supplied to the first bearing 45 to leak. In this embodiment, the seal member 371 made of an O-ring is disposed between the first bearing 45 and the first divided body 41, but the first bearing 45 may be press-fitted into the first divided body 41 without using the seal member 371.

[0038] The case 4 also has a second bearing 46, which rotatably supports the input shaft 6, at the other end side in the direction of the axis 60 (the right end side in the first embodiment). An input shaft hole 421 through which the input shaft 6 passes is formed in the second divided body 42, and the second bearing 46 is disposed in this input shaft hole 421. In the first embodiment, the input shaft 6 is indirectly supported by the second bearing 46 via the output body 8. In the first embodiment, the second bearing 46 is configured by a ball bearing. Note that the second bearing 46 is not limited to a ball bearing and various other bearings, such as a roller bearing, can also be used.

[0039] A seal member 373 made of an O-ring is disposed between the second bearing 46 and the second divided body 42. Disposing the seal member 373 makes it difficult for the grease supplied to the second bearing 46 to leak. Note that the seal member 373 may be a D-ring or the like instead of an O-ring, and is not particularly limited.

[0040] As shown in Figure 1, one end of a crank arm 18 is fixed to the end of the input shaft 6. A pedal 181 is rotatably attached to the other end of the crank arm 18. The rider of the electric bicycle 1 can transmit human power rotational force to the input shaft 6 by pedaling the pedal 181.

[0041] The input body 7 is disposed along the outer peripheral surface of the input shaft 6 and rotates integrally with the input shaft 6. The input body 7 is a cylindrical member with its axis 60 oriented in the left-right direction and disposed concentrically with the input shaft 6. The left-right length of the input body 7 is shorter than the left-right length of the input shaft 6. The input body 7 and the input shaft 6 have mating portions 711, 61 at parts along the axis 60 that matingly engage with each other so as to prevent relative rotation around the axis 60. In the first embodiment, mating portions 711, 61 formed of spline portions, serration portions, or the like are formed on the left end portion of the input body 7 (more specifically, the first input body 71 described later) and the input shaft 6 corresponding to this portion. The mating portions 711, 61 may be configured to be mated by male and female threads.

[0042] Furthermore, in the first embodiment, the input body 7 is divided into a first input body 71 and a second input body 72. The first input body 71 is connected to the input shaft 6. The first input body 71 is located at a part of the input shaft 6 in the left-right direction and is housed within the first divided body 41. A fitting portion 711 that fits with the input shaft 6 is formed at the left end of the first input body 71. A gap 70 is formed between the first input body 71 and the input shaft 6 in a portion to the right of the fitting portion 711 at the left end of the first input body 71. This makes it easier to insert the input shaft 6 into the cylindrical first input body 71.

[0043] The second input body 72 is connected to the first input body 71 at a position different from that of the first input body 71 in the direction of the axis 60 (to the right of the first input body 71 in the first embodiment), and transmits a rotational force to the output body 8. However, a portion of the second input body 72 may be located at the same position in the left-right direction as that of the first input body 71. In the first embodiment, the left end of the second input body 72 is located radially outward of the right end of the first input body 71, and they overlap in the radial direction. The first input body 71 and the second input body 72 have mating portions 712 and 721 that fit together so as to prevent relative rotation around the axis 60. In the first embodiment, mating portions 712 and 721 formed of spline portions, serration portions, or the like are formed at the right end of the first input body 71 and the left end of the second input body 72. Note that, in the present invention, "overlapping in the radial direction" refers to a state in which at least a portion of each object overlaps when viewed in the radial direction.

[0044] The output body 8 is disposed rotatably around the axis 60 along the outer peripheral surface of the input shaft 6 and receives a rotational force from the input body 7. The output body 8 penetrates the case 4 in the direction of the axis 60, but does not necessarily have to penetrate the case 4. The output body 8 is a generally cylindrical member with its axis 60 facing the left-right direction and disposed concentrically with the input shaft 6. The left-right length of the output body 8 is shorter than the left-right length of the input shaft 6. The right end of the output body 8 protrudes outside the case 4 through an input shaft hole 421 formed in the second divided body 42. The output body 8 is supported by a second bearing 46 disposed in the second divided body 42. The output body 8, together with the input shaft 6 and the input body 7, constitutes the rotating shaft unit 30. The rotating shaft unit 30 is supported by the case 4 via a first bearing 45 and a second bearing 46.

[0045] A front sprocket 191 is attached to a portion of the output body 8 that protrudes outside the case 4. The front sprocket 191 is attached to the output body 8 on one side in the direction of the axis 60 (the right side in the first embodiment). The front sprocket 191 rotates integrally with the output body 8. Also, 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.

[0046] As shown in FIG. 2 , in the first embodiment, a one-way clutch 32 is disposed between the input body 7 and the output body 8. When a rotational force is applied to the input body 7 in a direction that accelerates the electric bicycle 1 in the traveling direction (hereinafter referred to as the acceleration direction), the one-way clutch 32 transmits the rotational force to the output body 8, and when a rotational force is applied in the direction opposite to the acceleration direction, the one-way clutch 32 does not transmit the rotational force to the output body 8. Furthermore, when a rotational force in the acceleration direction is applied to the output body 8 via a speed reduction mechanism 9 (described later), the one-way clutch 32 does not transmit the rotational force to the input body 7. In the first embodiment, the one-way clutch 32 has a ratchet and is supplied with grease. Note that various types of one-way clutch 32 can be used as appropriate and are not limited thereto. For example, a roller-type one-way clutch or a sprag-type one-way clutch may be used, or a clutch that meshes in the direction of the axis 60 may be used.

[0047] The output body 8 has a web 81 and a rim 82 on the outer peripheral surface side at a portion overlapping with the input body 7 in the direction of the axis 60. The web 81 protrudes radially outward. The rim 82 is continuous with the outer radial end of the web 81. The length of the rim 82 in the direction of the axis 60 is longer than the length of the web 81 in the direction of the axis 60. The rim 82 has teeth 83 on its outer peripheral surface that mesh with the reduction mechanism 9.

[0048] The reduction mechanism 9 is housed in the case 4 and reduces the rotation of the motor 5 before transmitting it to the output body 8. The reduction mechanism 9 has two pairs of gears that mesh with each other. That is, the reduction mechanism 9 reduces the rotation of the motor 5 by so-called two-stage reduction before transmitting it to the output body 8. This makes it easier to obtain a large reduction ratio using the reduction mechanism 9.

[0049] The reduction gear mechanism 9 has a first transmission gear 91 and a second transmission gear 92. The outer diameter of the first transmission gear 91 is larger than the outer diameter of the second transmission gear 92. The number of teeth of the first transmission gear 91 is larger than the number of teeth of the second transmission gear 92.

[0050] The first transmission gear 91 rotates due to the rotational force of the rotating shaft 51 of the motor 5. In the first embodiment, the first transmission gear 91 is made of a cylindrical member, and has teeth 911 formed on its outer circumferential surface that mesh with teeth 54 formed on the rotating shaft 51 of the motor 5. The first transmission gear 91 is disposed along the outer circumferential surface of the transmission rotating shaft 90 of the reduction mechanism 9. In the first embodiment, the first transmission gear 91 is configured to receive the rotational force directly from the rotating shaft 51 of the motor 5, but a gear may be interposed therebetween.

[0051] The transmission rotation shaft 90 is rotatably housed in the case 4 with its axis oriented in the left-right direction. The right end of the transmission rotation shaft 90 is supported by a bearing 931 disposed in the second divided body 42. The left end of the transmission rotation shaft 90 is supported by a bearing 932 disposed in the retainer 38.

[0052] The first transmission gear 91 is connected to the transmission rotation shaft 90 via a one-way clutch 94. When a rotational force in the acceleration direction is applied to the first transmission gear 91, the one-way clutch 94 transmits this rotational force to the transmission rotation shaft 90, and when a rotational force in the direction opposite to the acceleration direction is applied, the one-way clutch 94 does not transmit this rotational force to the transmission rotation shaft 90. Furthermore, when a rotational force in the acceleration direction is applied to the transmission rotation shaft 90, the one-way clutch 94 does not transmit this rotational force to the first transmission gear 91.

[0053] The second transmission gear 92 is fixed to the right of the portion of the transmission rotation shaft 90 to which the one-way clutch 94 is fixed so as to rotate integrally with the transmission rotation shaft 90. Note that the second transmission gear 92 may also be fixed to the left of the portion of the transmission rotation shaft 90 to which the one-way clutch 94 is fixed (the portion to which the first transmission gear 91 is directly or indirectly fixed). The second transmission gear 92 transmits the rotational force received from the first transmission gear 91 via the transmission rotation shaft 90 to the toothed portion 83 of the output body 8. The second transmission gear 92 has toothed portions 921 on its outer circumferential surface that mesh with the toothed portions 83 formed on the rim 82 of the output body 8.

[0054] When the rider pedals 181 of the electric bicycle 1, a rotational force in the acceleration direction is applied to the input shaft 6. When the input shaft 6 rotates, the first input body 71 and the second input body 72 rotate integrally with the input shaft 6. The rotational force in the acceleration direction of the second input body 72 is applied to the output body 8 via the one-way clutch 32, causing the output body 8 and the front sprocket 191 to rotate in the acceleration direction. When the front sprocket 191 rotates in the acceleration direction, a rotational force in the acceleration direction is applied to the rear sprocket 192 via the chain 193, causing the rear sprocket 192 and the rear wheel 112 to rotate in the acceleration direction. This causes the electric bicycle 1 to move forward in the forward direction.

[0055] Furthermore, while the electric bicycle 1 is moving forward under human power, the rotational force from the motor 5 can be applied to the output body 8 as an auxiliary force. This will be explained in detail below. When the rotating shaft 51 of the motor 5 rotates in the acceleration direction, the first transmission gear 91 meshing with the rotating shaft 51 of the motor 5 rotates in the acceleration direction. The rotational force of the first transmission gear 91 in the acceleration direction is transmitted via the one-way clutch 94 to the transmission rotation shaft 90 and the second transmission gear 92 fixed to the transmission rotation shaft 90, causing the second transmission gear 92 to rotate in the acceleration direction. The rotational force of the second transmission gear 92 in the acceleration direction is transmitted to the output body 8 meshing with the second transmission gear 92. In other words, the output body 8 functions as a force combiner that combines the rotational force of the human power from the input body 7 and the rotational force from the motor 5. The motor unit 3 in the first embodiment is a so-called single-shaft motor unit 3. In the single-axis motor unit 3 , the rotational force of human power from the input body 7 and the rotational force from the motor 5 are combined in the case 4 of the motor unit 3 and output from the same output body 8 .

[0056] Next, a case will be described where the motor 5 is not driven while the electric bicycle 1 is moving forward under human power. In this case, the output body 8 is rotating in the acceleration direction, so the second transmission gear 92 and the transmission rotation shaft 90 that mesh with the output body 8 rotate in the acceleration direction, but the rotational force of the transmission rotation shaft 90 in the acceleration direction is not transmitted to the first transmission gear 91 by the one-way clutch 94. This prevents the rotation shaft 51 and rotor 52 from rotating when the motor 5 is not driven.

[0057] In the electric bicycle 1, the rotational force from the motor 5 is controlled in accordance with the torque applied to the input shaft 6 and the number of rotations per unit time of the input shaft 6. The torque applied to the input shaft 6 is detected by a torque detection unit 33. The torque detection unit 33 is disposed along the outer circumferential surface of the rotating shaft unit 30 within a partial range in the direction of the axis 60.

[0058] In the first embodiment, a magnetostrictive generating portion 331 having magnetic anisotropy is formed on the outer peripheral surface of the first input body 71. In addition, a coil 332 is disposed at a slight distance from the portion of the outer peripheral surface of the first input body 71 where the magnetostrictive generating portion 331 is provided. The magnetostrictive generating portion 331 and the coil 332 constitute a magnetostrictive torque sensor serving as the torque detection unit 33. Various types of magnetostrictive torque sensors can be appropriately used as such. In addition, the torque detection unit 33 is not limited to a magnetostrictive torque sensor.

[0059] The torque detection unit 33 is disposed to the left of the first transmission gear 91, the second transmission gear 92, the one-way clutch 32, and the second bearing 46 in the direction of the axis 60.

[0060] The number of rotations per unit time of the input shaft 6 is detected by an input shaft rotation detection section 34. The input shaft rotation detection section 34 is disposed in a partial range in the direction of the axis 60 along the outer peripheral surface of the rotary shaft unit 30.

[0061] In the first embodiment, a first rotor 341 having teeth and light-transmitting portions formed between the teeth at regular intervals in the circumferential direction is fixed to the right of the coil 332 of the torque detection unit 33 on the outer peripheral surface side of the input body 7 so as to rotate integrally with the input body 7. Furthermore, optical sensors 342 are arranged so as to sandwich the teeth of the first rotor 341 from the left and right. The optical sensor 342 has a light-emitting portion 343 arranged on the left side of the teeth and a light-receiving portion 344 arranged on the right side of the teeth, but the positional relationship between the light-emitting portion 343 and the light-receiving portion 344 is not limited. Various types of input shaft rotation detectors 34 having such a first rotor 341 and optical sensor 342 can be used as appropriate. Furthermore, the input shaft rotation detector 34 is not limited to having the first rotor 341 and optical sensor 342.

[0062] The motor unit 3 includes a control board 35 in the case 4, which has a control unit that controls the motor 5. The control unit 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). Various types of control units can be used as appropriate, and detailed descriptions will be omitted. The control unit controls the rotational force from the motor 5 based on the torque detected by the torque detection unit 33 and the rotation speed detected by the input shaft rotation detection unit 34.

[0063] The control board 35 and the rotor 52 at least partially overlap when viewed in the direction of the axis 60. This makes it easier to reduce the size of the motor unit 3 (case 4).

[0064] The motor unit 3 further includes a motor rotation detection unit 36 ​​that detects the rotation speed of the rotor 52. The motor rotation detection unit 36 ​​includes a second rotating body 361 that is attached to the rotating shaft 51 and rotates integrally with the rotating shaft 51 and the rotor 52, and a detection unit 362. The second rotating body 361 is magnetic. As the detection unit 362, a Hall IC that detects the magnetic force of the second rotating body 361 is disposed at a position corresponding to the rotational orbit of the second rotating body 361 of the motor 5. The detection unit 362 is attached to the control board 35. By directly attaching the detection unit 362 to the control board 35, connectors and wiring that connect the detection unit 362 to the control board 35 are not required, making it easier to reduce the size of the motor unit 3.

[0065] It should be noted that various types of motor rotation detectors 36 having such a magnet and a Hall IC can be appropriately used, but the motor rotation detector 36 is not limited to those having a magnet and a Hall IC.

[0066] The second divided body 42 of the case 4 has an integral heat dissipation section 424. The heat dissipation section 424 is connected to a heat-generating component on the inner surface of the case 4. The heat dissipation section 424 may be provided at a location where the case 4 protrudes inward. The heat-generating component is, for example, the control board 35 or the motor 5. The heat dissipation section 424 is connected to the control board 35 via a thermally conductive member 425. That is, in the first embodiment, the control board 35 is connected to the case 4. As a result, heat generated by the control board 35 is efficiently dissipated from the outer surface of the case 4 via the heat dissipation section 424. As described above, the retainer 38 may be formed of a material with good thermal conductivity, such as metal, and the control board 35 may be provided on the retainer 38, thereby connecting the control board 35 and the retainer 38. "Connected" refers to direct contact between the control board 35 and the retainer 38 or indirect connection via another member. With this configuration, heat generated in the control board 35 can be dissipated from the first divided body 41 via the retainer 38.

[0067] Furthermore, the retainer may be connected to any heat dissipation portion of the case 4. This allows generated heat to be dissipated from the case 4 via the retainer .

[0068] The motor unit 3 has a third bearing 47 located between the first bearing 45 and the second bearing 46 in the direction of the axis 60. The third bearing 47 rotatably supports the input body 7. In the first embodiment, the third bearing 47 is configured by a ball bearing. Note that the third bearing 47 is not limited to a ball bearing and various other bearings such as a roller bearing can also be used.

[0069] The provision of the third bearing 47 stabilizes the rotation of the rotating shaft unit 30. In other words, if the third bearing 47 were not provided, the rotating shaft unit 30 would be supported only by two bearings, the first bearing 45 and the second bearing 46. In this case, the portion of the rotating shaft unit 30 between the first bearing 45 and the second bearing 46 would be prone to vibration in the axial direction. In contrast, the provision of the third bearing 47 supports the portion between the first bearing 45 and the second bearing 46 from the outside of the axial direction, making it difficult for the output body 8 and the rotating shaft unit 30 including the output body 8 to vibrate in the axial direction. As a result, the rotation of the rotating shaft unit 30 is stabilized. When the rotation of the rotating shaft unit 30 is stabilized, the rotation of the front sprocket 191 is also stabilized, and the chain 193 wound around the front sprocket 191 is less likely to fall off the front sprocket 191.

[0070] In the first embodiment, the third bearing 47 supports the second input body 72. By having the third bearing 47 support the second input body 72 instead of the first input body 71, it is possible to support a portion close to the output body 8 to which force is applied from the reduction mechanism 9, and the rotation of the rotating shaft unit 30 becomes even more stable.

[0071] In the first embodiment, the third bearing 47 is located between the input body 7 (second input body 72) and the output body 8, which are overlapped in the radial direction of the input shaft 6. This allows the third bearing 47 to be supported by the output body 8, eliminating the need for the third bearing 47 to be attached to the case 4.

[0072] Furthermore, the third bearing 47 is located between the one-way clutch 32 and the torque detection unit 33 in the direction of the axis 60. As a result, the torque detection unit 33 is located between the first bearing 45 and the third bearing 47, and the one-way clutch 32 is located between the third bearing 47 and the second bearing 46 in the direction of the axis 60. This suppresses vibration in the radial direction of the shaft of the portion of the rotating shaft unit 30 where the torque detection unit 33 is located and the portion where the one-way clutch 32 is located.

[0073] In the first embodiment, the second bearing 46 and the third bearing 47 support the output body 8. The second bearing 46 is disposed in the case 4 and supports the output body 8 from the radially outer side. The third bearing 47 is disposed in the second input body 72 and supports the output body 8 from the radially inner side. The output body 8 is supported from both the radially outer and radially inner sides, making it difficult for the output body 8 and the rotating shaft unit 30 including the output body 8 to vibrate in the radial direction of the shaft. As a result, the rotation of the rotating shaft unit 30 becomes even more stable.

[0074] In the first embodiment, the motor unit 3 includes a retainer 38 that is separate from the case 4. The retainer 38 has a bearing 932 that supports a rotation shaft 90 of a gear included in the reduction gear mechanism 9. By providing the retainer 38 that is separate from the case 4, when inserting the motor 5 into the case 4 that has the motor accommodating portion 43 integrally therewith, the stator 53 can be inserted into the motor accommodating space 430 before the retainer 38 is attached to the case 4, making it easy to insert the stator 53 into the motor accommodating space 430.

[0075] Furthermore, neither of the bearings 931, 932 supporting the transmission rotation shaft 90 of the reduction gear mechanism 9 is attached to the case 4, and one of the bearings, the bearing 932, is attached to the retainer 38. If both of the bearings 931, 932 were attached to the case 4, the transmission rotation shaft 90 would be positioned across the left and right ends of the case 4, occupying a large proportion of the accommodation space within the case 4 and making the case 4 larger. In this embodiment, by attaching one of the bearings, the bearing 932, to the retainer 38, it is no longer necessary for the transmission rotation shaft 90 to be positioned across the left and right ends of the case 4, making it easier to make the transmission rotation shaft 90 and the case 4 smaller. Furthermore, when assembling the motor unit 3, the rotation shaft of the reduction gear mechanism 9 can be held in the retainer 38 via the bearing 932, making the assembly of the motor unit 3 easier.

[0076] Next, the motor unit 3 of the second embodiment will be described with reference to Figures 3 to 6. Note that the motor unit 3 of the second embodiment is largely the same as the motor unit 3 of the first embodiment, and therefore, the same reference numerals will be used to designate components corresponding to those of the motor unit 3 of the first embodiment, and a description thereof will be omitted. The following mainly describes components that differ from the first embodiment.

[0077] The motor unit 3 in the first embodiment is a so-called single-shaft motor unit 3, whereas the motor unit 3 in the second embodiment is a so-called two-shaft motor unit 3. In the two-shaft motor unit 3, the human-powered rotational force from the input body 7 and the rotational force from the motor 5 are output from different output bodies 802 and human-powered driving force output bodies 801, which will be described later.

[0078] In the second embodiment, the motor unit 3 includes a human-powered driving force output body 801 and an output body 802. The human-powered driving force output body 801 constitutes the rotary shaft unit 30. The rotational force applied to the input shaft 6 when the rider pedals the pedals 181 is transmitted to the human-powered driving force output body 801, and then transmitted via the sprocket 191, the chain 193, and the rear sprocket 192 to the rear wheel 112. Note that although the input shaft 6 is cylindrical and made of a solid member in the second embodiment, it may also be made of a hollow member.

[0079] The motor unit 3 includes an output body 802 separate from a human-powered drive force output body 801. The rotational force from the motor 5 is transmitted to the output body 802 via a speed reduction mechanism 9. In the second embodiment, the speed reduction mechanism 9 reduces the rotation of the motor 5 by a so-called single-stage reduction mechanism having only one pair of meshing gears, and transmits the reduced rotation to the output body 802. The speed reduction mechanism 9 includes a first transmission gear 91, but does not include the second transmission gear 92 of the first embodiment. The transmission rotation shaft 90 that constitutes the speed reduction mechanism 9 also serves as the output body 802. The first transmission gear 91 is connected to the output body 802 (transmission rotation shaft 90) via a one-way clutch 94, as in the first embodiment.

[0080] A sprocket 194, separate from the sprocket 191, is attached to a portion of the output body 802 that protrudes outside the case 4. The sprocket 194 is attached to the output body 802 on either side in the direction of the axis 60 (the right side in the second embodiment). The sprocket 194 rotates integrally with the output body 802. The chain 193 is wound around the sprockets 191, 192, and 194. The rotational force of the output body 802 is finally transmitted to the rear wheel 112 via the sprocket 194, the chain 193, and the rear sprocket 192.

[0081] In the second embodiment, the input shaft rotation detection unit 34 includes a third rotor 345 that rotates with the input shaft 6 and serves as a detected part, and a rotation center shaft 346 that is fixed to a part other than the rotary shaft unit 30. A fourth rotor 347 is attached to the outer circumferential surface of the input shaft 6. The outer circumferential surface of the input shaft 6 is attached to the inner circumferential surface of the fourth rotor 347 by press-fitting, mating, screwing, or the like, and rotates integrally with the input shaft 6. The fourth rotor 347 has teeth at the tip of a portion extending radially from the input shaft 6. A fifth rotor 348 having teeth that mesh with the teeth of the fourth rotor 347 is disposed on the rotational orbit of the teeth of the fourth rotor 347. A magnetized third rotor 345 is attached to the fifth rotor 348. The third rotor 345 rotates integrally with the fifth rotor 348 and is linked to the rotation of the input shaft 6. The rotation of the third rotor 345 is detected by a Hall IC, which will be described later.

[0082] The rotation center shaft 346 is cylindrical and has a uniform cross section, one end of which is fitted into the first divided body 41 and the other end of which is fitted into the second divided body 42, and does not rotate relative to the case 4. The magnetic force of the third rotating body 345 is detected by a Hall IC provided on the control board 35. The rotation center shaft 346 is inserted into the shaft hole of the fifth rotating body 348 and functions as the rotation axis of the fifth rotating body 348.

[0083] The third rotor 345 and the second rotor 361 overlap when viewed in a direction perpendicular to the axis 60. This improves the degree of freedom in designing the motor unit 3 and the electric bicycle 1.

[0084] The retainer 38 and the stator 53 at least partially overlap when viewed in the direction of the axis 60. This makes it easier to reduce the size of the motor unit 3 (case 4).

[0085] 3 and 4, reference numeral 48 denotes a metal bearing interposed between the input shaft 6 and the human-powered driving force output body 801, reference numeral 412 in FIG. 5 denotes a fastening member consisting of a bolt that fixes the retainer 38 to the first divided body 41, and reference numeral 413 denotes a fastening member consisting of a screw that fixes the control board 35 to the first divided body 41.

[0086] Next, a modified example will be described.

[0087] In the first embodiment, the reduction mechanism 9 reduces the rotation speed of the motor 5 by so-called two-stage reduction, and in the second embodiment, the reduction mechanism 9 reduces the rotation speed of the motor 5 by so-called one-stage reduction, but the reduction by the reduction mechanism 9 is not limited to one-stage reduction or two-stage reduction. The reduction mechanism 9 may also have three or more stages of reduction, that is, three or more pairs of meshing gears.

[0088] In the first and second embodiments, the retainer 38 is attached to the first division 41 by fasteners such as screws or by fitting, but the method of attaching the retainer 38 to the first division 41 is not limited. The retainer 38 may also be attached to the second division 42, as long as it is attached to at least the case 4. In this case, the retainer 38 may be attached to the case 4 via a separate member. For example, the retainer 38 may be attached to the case 4 via a separate member such as a rubber sheet or urethane sheet that functions as a vibration-damping member. The retainer 38 may also be in contact with both the first division 41 and the second division 42, or may be supported by both the first division 41 and the second division 42 via another member between them. In this case, the retainer 38 is more reliably fixed to the case 4. The retainer 38 may also be fitted to both the first division 41 and the second division 42. In this case, the assembly rigidity of the retainer 38 is improved, and the rigidity for receiving the bearing 932 provided in the retainer 38 is also improved. In addition, the meshing precision of the first transmission gear 91 and the second transmission gear 92 is improved, which is effective in quieting the motor unit 3. Furthermore, the rigidity of the entire case 4 is improved, making it less likely that gear rattle noise or electromagnetic noise from the motor 5 will leak outside the case 4.

[0089] The retainer 38 may be formed with a hole or notch through which the electric wires connecting the motor 5 and the control board 35 pass. This makes it easier to route the electric wires connecting the motor 5 and the control board 35, improving the design freedom of the motor unit 3 and the electric bicycle 1. Note that this hole or notch may be the contactable portion described above.

[0090] As is clear from the first embodiment, second embodiment, and their modifications described above, the motor unit 3 of the first aspect includes a case 4, a motor 5, an output body 8, a reduction gear mechanism 9, and a retainer 38. The motor 5 has a rotor 52 and a stator 53, and the stator 53 is housed in a motor housing space 430 in the case 4. The output body 8 is arranged to be rotatable about the axis 60. The reduction gear mechanism 9 is housed in the case 4 and transmits the rotation of the motor 5 to the output body 8 after reducing the rotation speed. The retainer 38 is housed in the case 4 and has a holding portion that holds a bearing 932 that supports the rotation shaft (transmission rotation shaft 90) of a gear of the reduction gear mechanism 9. At least a portion of the retainer 38 overlaps with at least a portion of the motor 5 when viewed from the direction of the axis 60.

[0091] According to the first aspect, when assembling the motor unit 3, the rotating shaft of the reduction gear mechanism 9 can be held by the retainer 38 via the bearing 932, making it easy to assemble the motor unit 3.

[0092] The second aspect can be realized in combination with the first aspect. In the second aspect, the retainer 38 is made of aluminum, an aluminum alloy, or a magnesium alloy.

[0093] According to the second aspect, it is easier to reduce the weight of the motor unit 3 compared to when the retainer 38 is made of steel or an iron-based metal.

[0094] The third aspect can be realized by combining it with the first aspect. In the third aspect, the retainer 38 is made of resin.

[0095] According to the third aspect, it is easier to reduce the weight of the motor unit 3 and the manufacturing costs compared to when the retainer 38 is made of metal.

[0096] The fourth aspect can be realized by combining with any one of the first to third aspects. In the fourth aspect, the reduction mechanism 9 has two pairs of gears that mesh with each other.

[0097] According to the fourth aspect, the reduction mechanism 9 can easily achieve a large reduction ratio.

[0098] The fifth aspect can be realized by combining with any one of the first to third aspects. In the fifth aspect, the reduction mechanism 9 has three pairs of gears that mesh with each other.

[0099] According to the fifth aspect, the reduction mechanism 9 can easily achieve a large reduction ratio.

[0100] The sixth aspect can be realized by combining any of the first to fifth aspects. In the sixth aspect, the case 4 is divided into a first divided body 41 and a second divided body 42 in the direction of the axis 60. The output body 8 is located on the second divided body side 42 in the direction of the axis 60. The motor accommodating space 430 is located in the first divided body 41.

[0101] According to the sixth aspect, the motor accommodating space 430 can be easily separated from the output body 8.

[0102] The seventh aspect can be realized by combining any of the first to fifth aspects. In the seventh aspect, the case 4 is divided into a first divided body 41 and a second divided body 42 in the direction of the axis 60. The output body 8 is located on the second divided body side 42 in the direction of the axis 60. The motor accommodating space 430 is located on the second divided body side 42.

[0103] According to the seventh aspect, the motor accommodating space 430 can be easily brought close to the output body 8.

[0104] The eighth aspect can be realized by combining with any of the first to seventh aspects. In the eighth aspect, a motor accommodating section 43 is formed in a part of the case 4, protruding outward more than the other parts of the case 4 and having a motor accommodating space 430 formed therein. A step section 433 is formed on an inner surface 431 of the motor accommodating section 43 facing the motor accommodating space 430, the step section 433 having a smaller diameter on the side closer to a back wall surface 432 of the motor accommodating section 43 facing the motor accommodating space 430 and a larger diameter on the side farther from the back wall surface 432.

[0105] According to the eighth aspect, the stator 53 can be easily positioned and inserted into the motor accommodating space 430.

[0106] The ninth aspect can be realized by combining with any of the first to eighth aspects. In the ninth aspect, the retainer 38 is attached to the case 4 on the side of the case 4 in the direction of the axis 60 where the motor accommodating space 430 is located.

[0107] According to the ninth aspect, the retainer 38 can easily cover the motor 5 (particularly the stator 53).

[0108] The tenth aspect can be realized in combination with the ninth aspect. In the tenth aspect, the retainer 38 is attached to the case 4 in contact with it.

[0109] According to the tenth aspect, the bearing 932 can be held in the case 4 via the retainer 38 .

[0110] The eleventh aspect can be realized in combination with the ninth aspect. In the eleventh aspect, the retainer 38 is attached to the case 4 via a vibration-isolating member.

[0111] According to the eleventh aspect, vibrations from the rotating shaft of the reduction mechanism 9 are less likely to be transmitted to the case 4 via the bearing 932 and the retainer .

[0112] The twelfth aspect can be realized by combining with any of the first to eleventh aspects. In the twelfth aspect, the motor unit 3 further includes a control board 35 having a control unit that controls the motor 5. The control board 35 is provided on the retainer 38.

[0113] According to the twelfth aspect, the control board 35 is held by the retainer 38 .

[0114] The thirteenth aspect can be realized by combining with any one of the first to twelfth aspects. In the thirteenth aspect, the motor unit 3 further includes a control board 35 having a control unit that controls the motor 5. At least a portion of the retainer 38 is located between the speed reduction mechanism 9 and the control board 35.

[0115] According to the thirteenth aspect, the grease or lubricating oil used in the reduction mechanism 9 is prevented from scattering and adhering to the control board 35.

[0116] The fourteenth aspect can be realized by combining with any one of the first to thirteenth aspects. In the fourteenth aspect, the motor unit 3 further includes a control board 35 having a control unit that controls the motor 5. The control board 35 is connected to the case 4 via a thermally conductive member.

[0117] According to the fourteenth aspect, the heat generated in the control board 35 can be easily dissipated efficiently through the case 4.

[0118] The fifteenth aspect can be realized by combining with any of the first to fourteenth aspects. In the fifteenth aspect, the motor unit 3 further includes a control board 35 having a control unit that controls the motor 5. A hole or a notch is formed in the retainer 38, through which an electric wire connecting the motor 5 and the control board 35 passes.

[0119] According to the fifteenth aspect, the electric wires connecting the motor 5 and the control board 35 can be easily laid, and the degree of freedom in designing the motor unit 3 is improved.

[0120] The sixteenth aspect can be realized by combining with any of the first to fifteenth aspects. In the sixteenth aspect, the retainer 38 and the stator 53 at least partially overlap with each other when viewed in the axis 60 direction.

[0121] According to the sixteenth aspect, the motor unit 3 can be easily made smaller.

[0122] The seventeenth aspect can be realized by combining with any one of the first to sixteenth aspects. In the seventeenth aspect, the motor unit 3 further includes a control board 35 having a control unit that controls the motor 5. The control board 35 and the rotor 52 at least partially overlap when viewed in the direction of the axis 60.

[0123] According to the seventeenth aspect, the motor unit 3 can be easily made smaller.

[0124] The 18th aspect can be realized by combining with any of the 1st to 17th aspects. In the 18th aspect, the case 4 has a first divided body 41 and a second divided body 42. The motor accommodating space 430 is formed integrally with the first divided body 41 or the second divided body 42.

[0125] According to the eighteenth aspect, the motor accommodating space 430 does not straddle the first divided body 41 and the second divided body 42, and therefore the shape and volume are highly stable.

[0126] The 19th aspect can be realized by combining with any one of the first to 18th aspects. In the 19th aspect, the retainer 38 has a contactable portion with which the stator 53 can come into contact.

[0127] According to the nineteenth aspect, the retainer 38 and the stator 53 come into contact with each other at the contactable portion, thereby preventing the stator 53 from rotating.

[0128] The twentieth aspect can be realized by combining with any of the first to nineteenth aspects. In the twentieth aspect, the case 4 has a heat dissipation portion, and the retainer 38 is connected to the heat dissipation portion.

[0129] According to the twentieth aspect, the generated heat can be dissipated from the case 4 via the retainer .

[0130] The 21st aspect can be realized by combining with any of the first to 20th aspects. In the 21st aspect, the motor unit 3 further includes an input shaft 6 that penetrates the case 4 in the direction of the axis 60 and is arranged rotatable around the axis 60, and is capable of transmitting a rotational force to the output body 8.

[0131] According to the 21st aspect, in a motor unit 3 used in a so-called two-axle electric bicycle 1, the transmission rotation shaft 90 does not need to be positioned across the left and right ends of the case 4, making it easier to make the transmission rotation shaft 90 and the case 4 smaller.

[0132] The 22nd aspect can be realized by combining with any of the 1st to 21st aspects. In the 22nd aspect, the motor unit 3 further includes an input shaft 6 that is rotatably arranged penetrating the case 4 in the direction of the axis 60, and a human-powered driving force output body 801 that outputs the rotational force of the input shaft 6. The human-powered driving force output body 801 rotates around a second axis different from the axis 60.

[0133] According to the 22nd aspect, in a motor unit 3 used in a so-called two-axle electric bicycle 1, the transmission rotation shaft 90 does not need to be positioned across the left and right ends of the case 4, making it easier to make the transmission rotation shaft 90 and the case 4 smaller.

[0134] The 23rd aspect can be realized by combining with either the 21st or 22nd aspect. In the 23rd aspect, the motor unit 3 further includes an input shaft rotation detection unit 34 and a motor rotation detection unit 36. The input shaft rotation detection unit 34 has a first rotating body 341 and detects the rotation speed of the input shaft 6. The motor rotation detection unit 36 ​​has a second rotating body 361 and detects the rotation speed of the rotor 52. The first rotating body 341 and the second rotating body 361 overlap when viewed in a direction perpendicular to the axis 60.

[0135] According to the twenty-third aspect, the degree of freedom in designing the motor unit 3 is improved.

[0136] The 24th aspect can be realized by combining with any of the first to 23rd aspects. In the 24th aspect, the retainer 38 overlaps with 10% to 80% of the inner region surrounded by the outer periphery of the stator 53 when viewed from the axis 60 direction.

[0137] According to the twenty-fourth aspect, the strength of the retainer 38 is maintained, and the weight of the retainer 38 can be easily reduced.

[0138] The 25th aspect can be realized by combining with any one of the first to 24th aspects. In the 25th aspect, the electric bicycle 1 includes the motor unit 3 of any one of the first to 24th aspects.

[0139] According to the twenty-fifth aspect, the transmission rotation shaft 90 does not need to be positioned across the left and right ends of the case 4, which makes it easier to make the transmission rotation shaft 90 and the case 4 smaller. [Explanation of symbols]

[0140] 1. Electric bicycle 191 sprocket 3 Motor Unit 34 Input shaft rotation detector 341 First Rotating Body 35 Control board 36 Motor rotation detector 361 Second Rotating Body 38 Retainer 4 cases 41 1st division body 42 Second division body 43 Motor housing 430 Motor housing space 431 Inner surface 432 Back wall 433 Step 5 motors 51 Rotation axis 52 rotor 53 Stator 6 Input shaft 60 axis 8 Output Body 801 Human-powered driving force output body 802 Output Body 9 Reduction mechanism 90 Rotating shaft (transmission rotating shaft) 932 Bearings

Claims

1. Case and a motor having a rotor and a stator, the stator being accommodated in a motor accommodating space within the case; an output body arranged to be rotatable about an axis; a reduction mechanism housed in the case, which reduces the rotation speed of the motor and transmits the reduced speed to the output body; a control board having a control unit for controlling the motor; a retainer that is housed in the case and has a holding portion that holds a bearing that supports a rotation shaft of a gear included in the reduction mechanism, At least a portion of the retainer overlaps with at least a portion of the motor when viewed from the axial direction, the retainer has a partition wall that separates the reduction mechanism and the control board. Motor unit for electric bicycles.

2. The retainer is made of aluminum, an aluminum alloy, or a magnesium alloy. The motor unit for an electric bicycle according to claim 1.

3. The retainer is made of resin. The motor unit for an electric bicycle according to claim 1.

4. The reduction mechanism has two pairs of gears that mesh with each other. The motor unit for an electric bicycle according to any one of claims 1 to 3.

5. The reduction mechanism has three pairs of gears that mesh with each other. The motor unit for an electric bicycle according to any one of claims 1 to 3.

6. The case is divided into a first divided body and a second divided body in the axial direction, the output body is located on the second divided body side in the axial direction, The motor accommodating space is located in the first divided body. The motor unit for an electric bicycle according to any one of claims 1 to 5.

7. The case is divided into a first divided body and a second divided body in the axial direction, the output body is located on the second divided body side in the axial direction, The motor accommodating space is located in the second divided body. The motor unit for an electric bicycle according to any one of claims 1 to 5.

8. a motor accommodating portion is formed in a part of the case, protruding outward from the other part of the case and having the motor accommodating space formed therein; A step portion is formed on an inner surface of the motor accommodating portion facing the motor accommodating space, the step portion having a smaller diameter on the side closer to a back wall surface facing the motor accommodating space of the motor accommodating portion and a larger diameter on the side farther from the back wall surface. The motor unit for an electric bicycle according to any one of claims 1 to 7.

9. The retainer is attached to the case on the side of the case where the motor accommodating space is located in the axial direction. The motor unit for an electric bicycle according to any one of claims 1 to 8.

10. The retainer is attached in contact with the case. The motor unit for an electric bicycle according to claim 9.

11. The retainer is attached to the case via a vibration-isolating member. The motor unit for an electric bicycle according to claim 9.

12. The control board is disposed on the retainer. The motor unit for an electric bicycle according to any one of claims 1 to 11.

13. At least a portion of the retainer is located between the reduction mechanism and the control board. The motor unit for an electric bicycle according to any one of claims 1 to 12.

14. The control board is connected to the case via a thermally conductive member. The motor unit for an electric bicycle according to any one of claims 1 to 13.

15. The retainer has a hole or a notch through which an electric wire connecting the motor and the control board passes. The motor unit for an electric bicycle according to any one of claims 1 to 14.

16. The retainer and the stator are at least partially overlapped when viewed in the axial direction. The motor unit for an electric bicycle according to any one of claims 1 to 15.

17. The control board and the rotor are at least partially overlapped when viewed in the axial direction. The motor unit for an electric bicycle according to any one of claims 1 to 16.

18. the case has a first divided body and a second divided body, The motor accommodating space is formed integrally with the first divided body or the second divided body. The motor unit for an electric bicycle according to any one of claims 1 to 5 and 8 to 17.

19. The retainer has a contactable portion with which the stator can come into contact. The motor unit for an electric bicycle according to any one of claims 1 to 18.

20. The case has a heat dissipation portion, and the retainer is connected to the heat dissipation portion. The motor unit for an electric bicycle according to any one of claims 1 to 19.

21. an input shaft that penetrates the case in the axial direction and is arranged rotatably about the axis, and that can transmit a rotational force to the output body; The motor unit for an electric bicycle according to any one of claims 1 to 20.

22. an input shaft rotatably disposed to pass through the case in the axial direction; a manual drive force output body that outputs the rotational force of the input shaft, The human-powered driving force output body rotates about a second axis different from the axis. The motor unit for an electric bicycle according to any one of claims 1 to 20.

23. an input shaft rotation detection unit having a first rotor and detecting the rotation speed of the input shaft; a motor rotation detection unit having a second rotating body and detecting the rotation speed of the rotor, The first rotating body and the second rotating body overlap when viewed in one direction perpendicular to the axial direction.

23. The motor unit for an electric bicycle according to claim 21 or 22.

24. The retainer overlaps with 10% to 80% of an inner region surrounded by an outer periphery of the stator when viewed from the axial direction. The motor unit for an electric bicycle according to any one of claims 1 to 23.

25. The retainer is attached in contact with a thick portion of the case. The motor unit for an electric bicycle according to claim 9.

26. The case is divided into a first divided body and a second divided body in the axial direction, The retainer is attached to the first divided body and the second divided body in contact with each other. The motor unit for an electric bicycle according to claim 1.

27. ​​The bearing is arranged radially inward of the rotating shaft relative to the gear and at a position overlapping at least a portion of the gear when viewed from the radial direction. The motor unit for an electric bicycle according to claim 1.

Images