Motor unit and electric bicycle

Abstract

To provide a motor unit that can easily be reduced in the size of a case by reducing the width of the case and to provide an electric bicycle.SOLUTION: A motor unit 3 includes: a case 4; a motor 5 accommodated in the case 4 and having a motor rotation shaft 51 and a rotor 52 that rotates integrally with the motor rotation shaft 51; an input shaft 6; an output body 8; and a speed reduction mechanism 9. The input shaft 6 extends through the case 4 in the direction of the axis 600 and is disposed so as to be rotatable about the axis 600. The output body 8 extends through the case 4 in the direction of the axis 600 and is disposed so as to be rotatable about the axis 600. The speed reduction mechanism 9 is accommodated in the case 4, reduces the speed of rotation of the motor 5 and transmits the rotation to the output body 8. The speed reduction mechanism 9 includes a plurality of pairs (91, 92) of gears (911, 912; 921, 922) that mesh with each other. In at least one pair of the plurality of pairs of gears, respective central axes of rotations of the gears are orthogonal to each other.SELECTED DRAWING: Figure 3

Description

[Technical Field]

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

[0002] Electrically assisted bicycles equipped with a motor drive unit are known (see, for example, Patent Document 1). The motor drive unit disclosed in Patent Document 1 includes a unit case, a motor, a crankshaft, a linkage fitted to a sprocket, and a reduction mechanism.

[0003] The reduction mechanism is provided with two pairs of gears: one pair consisting of a toothed portion that rotates integrally with the motor's rotating shaft and a large-diameter gear portion that meshes with it, and the other pair consisting of a small-diameter gear portion that rotates integrally with the large-diameter gear portion and a large-diameter gear portion that meshes with it as an interlocking body. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] International Publication No. 2014 / 184826 Summary of the Invention [Problem to be solved by the invention]

[0005] In conventional electrically assisted bicycles such as those described above, the motor is positioned so that the axis of the crankshaft and the axis of the motor's rotating shaft are parallel. This means that the motor body, the motor's rotating shaft, and the motor's teeth are aligned in the axial direction of the crankshaft, making it difficult to shorten the length (width) of the unit case in the axial direction of the crankshaft, and therefore difficult to make the unit case more compact.

[0006] In view of the above-mentioned problems of the conventional art, the present disclosure aims to provide a motor unit and an electric bicycle in which the width of the case can be reduced to facilitate downsizing of the case. [Means for solving the problem]

[0007] In order to solve the above problem, one embodiment of the motor unit includes a case, a motor housed in the case and having a motor rotating shaft and a rotor rotating integrally with the motor rotating shaft, an input shaft, an output body, a reduction mechanism, and a rotation detection unit, a substrate accommodated in the case, The input shaft passes through the case in the axial direction and is arranged to be rotatable about the axis. The case has a first divided body and a second divided body, and has an internal storage space in which the interior of the first divided body and the interior of the second divided body are continuous. The output body is disposed so as to pass through the case in the axial direction and be rotatable about the axis. The reduction mechanism is housed in the case and reduces the rotation of the motor before transmitting the reduced rotation to the output body. The rotation detection unit has a rotor provided on the input shaft and detects rotation of the input shaft. A first bearing that rotatably supports the input shaft is disposed in the first divided body. A second bearing that rotatably supports the output body is disposed in the second divided body. The reduction mechanism and the substrate are housed in the housing space. The reduction mechanism is Multiple Gear Pair With The plurality of teeth In at least one pair of wheels, the central axes of rotation of the gears are perpendicular to each other. One of the plurality of gear pairs includes a gear pair consisting of one gear and another gear that meshes with the one gear and rotates integrally with the output body. The central axis of the motor rotating shaft is oriented perpendicular to the axial direction. The substrate is provided on the first bearing side of the other gear and on the second bearing side of the rotating body in the axial direction of the input shaft.

[0008] In order to solve the above problem, one form of electric bicycle includes the motor unit. [Effects of the Invention]

[0009] In the motor unit and the electric bicycle according to the above-described embodiment of the present disclosure, the width of the case can be reduced, making it easy to reduce the size of the case. [Brief explanation of the drawings]

[0010] [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 of the frame and motor unit 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 rotating shaft of the motor, and the rotating transmission shaft of the reduction mechanism. [Figure 4] FIG. 4 is a side view of the motor unit. [Figure 5]FIG. 5 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 6] FIG. 6 is a side view of the motor unit. [Figure 7] FIG. 7 is a partially see-through side view of an electric bicycle according to a modified example. [Figure 8] FIG. 8 is a partially see-through side view of an electric bicycle according to a further modified example. [Figure 9] FIG. 9 is a partially see-through side view of an electric bicycle according to a further modified example. [Figure 10] FIG. 10 is a partially see-through side view of an electric bicycle according to a further modified example. [Figure 11] FIG. 11 is a partially see-through side view of an electric bicycle according to a further modified example. [Figure 12] FIG. 12 is a partially see-through side view of an electric bicycle according to a further modified example. DETAILED DESCRIPTION OF THE INVENTION

[0011] The present disclosure relates to a motor unit and a two-wheeled vehicle, and more specifically to a motor unit including a case, a motor, an input shaft, an output body, and a reduction mechanism, and to an electric bicycle such as an electrically assisted bicycle or an electric motorcycle including this motor unit.

[0012] A first embodiment of a motor unit and an electric bicycle according to the present disclosure will now be described with reference to FIGS.

[0013] 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.

[0014] 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.

[0015] 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.

[0016] As shown in FIG. 2, 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. As shown in FIG. 1, 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.

[0017] As shown in FIG. 2, 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.

[0018] 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. As shown in FIG. 1 , a shaft extending downward from the saddle 13 is inserted into the opening at the upper end of the stand pipe 104. By fixing this shaft to the stand pipe 104, the saddle 13 is fixed to the stand pipe 104. A bracket 2 is fixed to the lower end of the stand pipe 104.

[0019] As shown in FIG. 2, the lower pipe 103 is a tubular 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 is inclined downward from 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. The bracket 2 is part of the frame 10 and supports the motor unit 3.

[0020] A motor unit 3 is fixed to the underside of the bracket 2 and is supported by the bracket 2. A wiring space 20 is formed between the inner surface of the bracket 2 and the outer surface of the motor unit 3.

[0021] The rear end of the down pipe 103 is fixed to the front end of the bracket 2 by fitting (including shrink fitting), fastening, welding, or the like. In the first embodiment, a through hole 25 that passes through vertically is formed in the front end of the bracket 2, and a tubular portion 251 protrudes from the area surrounding the through hole 25. The rear end of the down pipe 103 is fitted over this tubular portion 251.

[0022] The lower end of the standpipe 104 is fixed to the middle part of the bracket 2 in the front-rear direction by fitting (including shrink fitting), fastening, welding, or the like. In the first embodiment, a through hole 26 that penetrates vertically is formed in the middle part of the bracket 2, and a tubular portion 261 protrudes from the area surrounding the through hole 26. The lower end of the standpipe 104 is fitted over and covered with this tubular portion 261.

[0023] The front ends of the chainstays 106 are fixed to the rear end of the bracket 2 by fitting (including shrink fitting), fastening, welding, or the like. The chainstays 106 are two hollow or solid members that extend generally rearward from the bracket 2. In the first embodiment, the front ends of the cylindrical chainstays 106 are fixed to the rear end of the bracket 2 by welding. Furthermore, a through-hole 27 that passes through vertically is formed in the bracket 2 at a position corresponding to the internal space of the chainstays 106.

[0024] As shown in FIG. 1, 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 a rear wheel 112 is rotatably attached to this part.

[0025] As shown in FIG. 2, the bracket 2 and the lower pipe 103 have a battery mounting portion 16 to which a battery 15 (see FIG. 1) for supplying power to the motor unit 3 is mounted. The battery mounting portion 16 has a lower support portion 161 formed on the bracket 2 and an upper support portion 162 formed on the lower pipe 103. The lower support portion 161 is mounted to support the battery 15 so that the lower end of the battery 15 does not easily fall off. The lower support portion 161 also has a plurality of terminals that are electrically connected to a plurality of battery terminals for power supply or signals that are formed on the lower end of the battery 15. One end of each of the plurality of terminals is electrically connected to one end of a wiring 163.

[0026] The upper support portion 162 has a locking device to which the upper end of the battery 15 is attached, and which locks the battery 15 so that the battery 15 does not fall off.

[0027] Furthermore, the shift wires 17 connecting the shift operation unit and the shift mechanism and the brake wires are passed through the lower pipe 103 and the wiring space 20 .

[0028] The motor unit 3 will be described below with reference to Fig. 3. 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.

[0029] 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, stainless steel, or a magnesium alloy, but a non-metal may also be used, and the material of the case 4 is not particularly limited.

[0030] 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. In the first embodiment, the case 4 is divided in the left-right direction, but the case 4 may also be divided in the front-rear direction, the up-down direction, or in another direction. The case 4 will be described in more detail later.

[0031] The first division body 41 has an internal storage space that opens to the right. The first division body 41 also has a motor cup 57. The motor cup 57 protrudes in a direction perpendicular to an axis 600 (described later) and stores the motor 5 therein. The motor cup 57 is attached to a portion of the first division body 41. The motor cup 57 is fixed to the first division body 41 by a fastening member 571 made of a bolt. In the first embodiment, the motor cup 57 is attached to the first division body 41, but the motor cup 57 may also be attached to the second division body 42, or may be attached across both the first division body 41 and the second division body 42.

[0032] Although the motor cup 57 and the case 4 are formed separately, the motor cup 57 may be formed integrally with the case 4. For example, the entire motor cup 57 may be formed integrally with the first division 41. Furthermore, although not shown, the entire motor cup 57 may be formed integrally with the second division 42, or a portion of the motor cup 57 may be formed integrally with the first division 41 and the remaining portion may be formed integrally with the second division 42. In this case, the first division 41 and the second division 42 are combined to form the motor cup 57. The internal storage space of the second division 42 is open to the left. The first division 41 and the second division 42 are joined from the left and right so that their storage spaces are continuous, and are fastened to each other with fastening members such as bolts. The case 4 is formed by fastening the first division 41 and the second division 42 to each other. The size, shape, thickness, etc. of the case 4 are not particularly limited. Furthermore, the storage space formed inside the case 4 may or may not be sealed.

[0033] The motor 5 is attached to the case 4. More specifically, the motor 5 is housed mainly in a motor cup 57 attached to the first divided body 41. The motor 5 is housed in the case 4. The motor 5 has a motor rotating shaft 51, a rotor 52 that rotates integrally with the motor rotating shaft 51, and a stator 53. The rotor 52, the stator 53, and a portion of the motor rotating shaft 51 are located within the motor cup 57. The motor rotating shaft 51 is rotatably housed such that its central axis of rotation is oriented perpendicular to the axis 600. Note that the central axis of the motor rotating shaft 51 may be perpendicular to the axis 600, and the motor rotating shaft 51 and the axis 600 may be in a torsional relationship. Alternatively, the central axis of the motor rotating shaft 51 may not be perpendicular to the axis 600, and the motor rotating shaft 51 and the axis 600 may be in a torsional relationship. The motor rotating shaft 51 protrudes from the stator 53 to one side, and teeth 54 that mesh with the reduction gear mechanism 9 are formed on the outer surface of the protruding portion. The protruding portion of the motor rotating shaft 51 and the teeth 54 formed on its outer surface form a first gear 911 that rotates integrally with the motor rotating shaft 51. Both ends of the motor rotating shaft 51 are supported by a rotating shaft support bearing 551 disposed in the second divided body 42 and a rotating shaft support bearing 552 disposed in the motor cup 57, respectively.

[0034] The input shaft 6 penetrates the case 4 in the direction of an axis 600 (the left-right direction in the first embodiment) and is arranged to be rotatable around the axis 600 of the input shaft 6. The input shaft 6 has an input shaft body 60 and an input body 7. In the first embodiment, the input shaft body 60 is made of a hollow member, but it may also be made of a solid member.

[0035] The case 4 has a first bearing 45, which rotatably supports the input shaft 60, at one end side in the direction of the axis 600 (the left end side in the first embodiment). An input shaft hole 411 through which the input shaft 60 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.

[0036] The case 4 also has a second bearing 46, which rotatably supports the output body 8, at the other end side in the direction of the axis 600 (the right end side in the first embodiment). An input shaft hole 421, through which the input shaft body 60 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 body 60 is indirectly supported by the second bearing 46 via the output body 8. In the first embodiment, the second bearing 46 is formed 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.

[0037] As shown in Figure 1, one end of a crank arm 18 is fixed to the end of the input shaft 60. 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 60 by pedaling the pedal 181.

[0038] As shown in FIG. 3 , the input body 7 is disposed along the outer peripheral surface of the input shaft 60 and rotates integrally with the input shaft 60. The input body 7 is a cylindrical member with its axis 600 oriented in the left-right direction and disposed concentrically with the input shaft 60. The left-right length of the input body 7 is shorter than the left-right length of the input shaft 60. The input body 7 and the input shaft 60 have mating portions 711, 61 at a portion in the direction of the axis 600 that fit together so as to prevent relative rotation around the axis 600. In the first embodiment, the mating portions 711, 61, which are formed of spline portions, serration portions, or the like, are formed on the left end of the input body 7 and the input shaft 60 corresponding to this portion. The mating portions 711, 61 may be configured to fit together using male and female threads.

[0039] Furthermore, in the first embodiment, the input body 7 is connected to the input shaft 60. A gap 70 is formed between the input body 7 and the input shaft 60. This makes it easier to insert the input shaft 60 into the cylindrical input body 7.

[0040] The output body 8 is disposed along the outer peripheral surface of the input shaft body 60 so as to be rotatable around the axis 600 and penetrates the case in the direction of the axis 600. The output body 8 receives a rotational force from the input body 7. The input body 7 and the output body 8 have a connecting portion that connects the input body 7 and the output body 8 so that they rotate together. A one-way clutch may be disposed between the input body 7 and the output body 8 to prevent rotational force from being transmitted to the input body 7 when the rotational force is applied to the output body 8 in a direction that accelerates the electric bicycle 1 in the direction of travel (hereinafter referred to as the acceleration direction). With this one-way clutch, the input shaft 6 will not co-rotate when the electric bicycle 1 is driven solely by the driving force of the motor 5 (e.g., in the push-walk mode). A spline portion 73 consisting of concave and convex portions arranged in a circumferential direction is formed on the outer peripheral surface of the input body 7. Similarly, a spline portion 81 consisting of concave and convex portions arranged in a circumferential direction and meshing with the spline portion 73 is formed on the inner peripheral surface of the output body 8. The spline portion 73 and the spline portion 81 form a connecting portion.

[0041] The output body 8 is a generally cylindrical member with its axis 600 oriented in the left-right direction and arranged concentrically with the input shaft 60. The left-right length of the output body 8 is shorter than the left-right length of the input shaft 60. The right end of the output body 8 passes through an input shaft hole 421 formed in the second divided body 42 and protrudes outside the case 4. The output body 8 is supported by a second bearing 46 arranged in the second divided body 42. The output body 8, together with the input shaft 60 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.

[0042] A front sprocket 191 is fixed to a portion of the output body 8 that protrudes outside the case 4 by a lock ring 195. 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.

[0043] By forming a connecting portion consisting of the spline portion 73 and the spline portion 81 on the input body 7 (input shaft 6) and the output body 8, the input shaft 6 and the output body 8 rotate integrally, and the rotation speed of the input shaft 6 matches the rotation speed of the output body 8. As a result, the phases of the rotation of the input shaft 6 (input shaft body 60 and input body 7), the output body 8, and the front sprocket 191 around the axis 600 are fixed.

[0044] Furthermore, when a so-called coaster brake is employed, such a connecting portion functions effectively. Note that the connecting portion is not limited to the spline portion 73 and the spline portion 81, and may be, for example, a portion in which a key groove is formed on the outer surface of the input body 7 and the output body 8 and a key is fitted into the key groove, or may be formed with serrations.

[0045] As shown in FIG. 3 , a fourth gear 922 constituting the reduction gear mechanism 9 is attached to the output body 8. The fourth gear 922 has teeth 82 of the reduction gear mechanism 9 on its outer circumferential surface. The fourth gear 922 is a part of the output body 8 and rotates integrally with the output body 8. The fourth gear 922 receives the rotational force of the motor 5 and transmits the rotational force to the output body 8. In the first embodiment, a one-way clutch 316 is provided between the reduction gear mechanism 9 and the output body 8. Specifically, the fourth gear 922 is connected to the output body 8 via the one-way clutch 316. The one-way clutch 316 is disposed on the outer periphery of the output body 8, and the central axis of rotation of the one-way clutch 316 is located on the axis 600. This eliminates the need to dispose the one-way clutch 316 in a portion of the case 4 away from the input shaft 6 and the output body 8, making it easier to create space in a portion of the case 4 away from the input shaft 6 and the output body 8.

[0046] When a rotational force in the acceleration direction is applied from motor 5 to fourth gear 922, one-way clutch 316 transmits this rotational force to output body 8, but when a rotational force in the opposite direction to the acceleration direction is applied, one-way clutch 316 does not transmit this rotational force to output body 8. Furthermore, when a rotational force in the acceleration direction is applied to output body 8, one-way clutch 316 does not transmit this rotational force to fourth gear 922. Note that, because one-way clutch 316 is disposed between reduction mechanism 9 and output body 8, when a rotational force in the acceleration direction is applied to output body 8, the members of reduction mechanism 9 provided on transmission rotation shaft 310 and rotor 52 connected to reduction mechanism 9 via tooth portion 54 do not rotate together. This allows the rider to enjoy a light riding feel when electric bicycle 1 is traveling with motor 5 stopped.

[0047] 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 a plurality of pairs of gears that mesh with each other. At least one of the plurality of gear pairs has central axes of rotation that are perpendicular to each other. In the first embodiment, the reduction mechanism 9 has two gear pairs, a first gear pair 91 and a second gear pair 92.

[0048] The first gear pair 91 is composed of the above-mentioned first gear 911 that rotates integrally with the motor rotating shaft 51, and a second gear 912 that is arranged along the outer circumferential surface of the transmission rotating shaft 310. The transmission rotating shaft 310 is rotatably housed in the case 4 so that the central axis of rotation is parallel to the axis 600. Both ends of the transmission rotating shaft 310 are supported by a transmission rotating shaft support bearing 314 that is arranged in the second division body 42 and a transmission rotating shaft support bearing 315 that is arranged in the first division body 41.

[0049] The central axis of the first gear 911 and the central axis of the second gear 912 that make up the first gear pair 91 are perpendicular to each other. The first gear pair 91 in the first embodiment has spiral bevel gears. That is, the first gear 911 and the second gear 912 make up a spiral bevel gear. Note that the first gear pair 91 may have a straight bevel gear, hypoid gear, face gear, or screw gear instead of a spiral bevel gear. For example, straight bevel gears offer advantages such as compact size, improved transmission efficiency, and easier assembly. Furthermore, for example, hypoid gears offer advantages such as a larger reduction ratio.

[0050] The second gear pair 92 is composed of a third gear 921 arranged along the outer circumferential surface of the transmission rotation shaft 310 and the above-mentioned fourth gear 922 that rotates integrally with the output body 8. The central axes of the third gear 921 and the fourth gear 922 that constitute the second gear pair 92 are parallel to each other. The second gear pair 92 in the first embodiment has spur gears. That is, the third gear 921 and the fourth gear 922 are spur gears. Note that the third gear 921 and the fourth gear 922 may be helical gears instead of spur gears.

[0051] The outer diameter of the second gear 912 is larger than the outer diameter of the third gear 921. The second gear 912 and the third gear 921 rotate integrally with the transmission rotation shaft 310.

[0052] Teeth 313 are formed on the outer circumferential surface of the second gear 912. The teeth 313 mesh with teeth 54 formed on the motor rotary shaft 51 of the motor 5, and are rotated by the rotational force received from the motor rotary shaft 51.

[0053] Teeth 317 are formed on the outer circumferential surface of the third gear 921. The teeth 317 mesh with teeth 82 of the fourth gear 922, and transmit the rotational force received from the second gear 912 via the transmission rotation shaft 310 to the teeth 82 of the fourth gear 922.

[0054] When the rider pedals 181 of the electric bicycle 1, a rotational force in the acceleration direction is applied to the input shaft 60. When the input shaft 60 rotates, the input body 7 rotates integrally with the input shaft 60. The rotational force in the acceleration direction of the input body 7 is applied to the output body 8 in the acceleration direction, 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 motor rotation shaft 51 of the motor 5 rotates in the acceleration direction, the second gear 912, which meshes with the first gear 911 that rotates integrally with the motor rotation shaft 51 of the motor 5, rotates in the acceleration direction. The rotational force of the second gear 912 in the acceleration direction is transmitted to the transmission rotation shaft 310 and the third gear 921 fixed to the transmission rotation shaft 310, causing the third gear 921 to rotate in the acceleration direction. The rotational force of the third gear 921 in the acceleration direction is transmitted to the fourth gear 922 that meshes with the third gear 921, and is further transmitted to the output body 8 via the one-way clutch 316. 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.

[0056] In the electric bicycle 1, the rotational force from the motor 5 is controlled in accordance with the torque applied to the input shaft 60 and the number of rotations per unit time of the input shaft 60. The torque applied to the input shaft 60 is detected by the torque detection unit 33. The torque detection unit 33 is disposed within a partial range in the direction of the axis 600 along the outer circumferential surface of the rotating shaft unit 30.

[0057] In the first embodiment, a magnetostrictive generating portion 331 having magnetic anisotropy is formed on the outer peripheral surface of the input body 7. In addition, a coil 332 is disposed at a slight distance from the portion of the outer peripheral surface of the input body 7 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.

[0058] The number of rotations per unit time of the input shaft 60 is detected by the rotation detector 34. The rotation detector 34 is disposed along the outer peripheral surface of the rotary shaft unit 30 in a partial range in the direction of the axis 600.

[0059] In the first embodiment, a 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 rotor 341 from the left and right. The optical sensor 342 has a light-emitting portion arranged on the left side of the teeth and a light-receiving portion arranged on the right side of the teeth, but the positional relationship between the light-emitting portion and the light-receiving portion is not limited. Various rotation detection units 34 having such a rotor 341 and optical sensor 342 can be appropriately used. Furthermore, the rotation detection unit 34 is not limited to having the rotor 341 and optical sensor 342.

[0060] The motor unit 3 has a control board 35 disposed in a case 4, the control board 35 having 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 rotation detection unit 34.

[0061] In the first embodiment, the central axes of rotation of the pair of first gear 911 and second gear 912 are perpendicular to each other, so it is easy to make the central axis of motor rotation shaft 51 of motor 5 perpendicular to the direction of axis 600. This shortens the length of motor 5 and reduction mechanism 9 arranged in case 4 in the direction of axis 600, and shortens the width of case 4, reducing the so-called Q factor, and making it possible to make case 4 more compact.

[0062] In the first embodiment, the rotation speed of the input shaft 6 matches the rotation speed of the output body 8. In other words, no gear is interposed between the input shaft 6 and the output body 8 to transmit the rotational force of the input shaft 6 to the output body 8. Therefore, no gear rattle noise, which is likely to occur when gears are interposed, occurs, making it easy to configure a quiet motor unit 3.

[0063] Furthermore, in the first embodiment, the reduction mechanism 9 has two gear pairs consisting of a first gear pair 91 and a second gear pair 92, and the rotational force of the motor 5 is transmitted to the output body 8 by so-called two-stage reduction, making it easy to achieve large reduction in speed.

[0064] Furthermore, in the first embodiment, the tooth portion 82 of the fourth gear 922 is a helical tooth, which improves the meshing ratio and makes it easier to configure a quiet motor unit 3.

[0065] Next, a motor unit 3 of a second embodiment will be described with reference to Figures 5 and 6. The motor unit 3 of the second embodiment is largely the same as the motor unit 3 of the first embodiment. Below, differences from the first embodiment will be mainly described.

[0066] In the first embodiment, the first gear pair 91 has spiral bevel gears. In contrast, in the second embodiment, the first gear pair 91 has worm gears. The first gear 911, one of the components of the first gear pair 91, is made up of a worm gear, and the second gear 912, the other of the first gear pair 91, is made up of a worm wheel. The spiral tooth portion 54 of the first gear 911 and the tooth portion 313 of the second gear 912 mesh with each other.

[0067] In the second embodiment, the length of the motor 5 and reduction mechanism 9 arranged inside the case 4 in the direction of the axis 600 can be shortened, and the width of the case 4 can be shortened to reduce the so-called Q factor, thereby making the case 4 more compact.

[0068] Next, modifications of the first and second embodiments will be described.

[0069] A one-way clutch may be disposed between the input body 7 and the output body 8. In this case, the input shaft 6 is not rotated by the drive of the motor 5. Therefore, when pushing the electric bicycle 1 driven only by the motor 5, the crank arm 18 does not rotate with it, allowing the rider to maneuver the bicycle body easily. The one-way clutch transmits a rotational force to the output body 8 when a rotational force in the acceleration direction is applied to the input body 7, but does not transmit this rotational force to the output body 8 when a rotational force in the opposite direction to the acceleration direction is applied. Furthermore, this one-way clutch does not transmit a rotational force to the input body 7 when a rotational force in the acceleration direction is applied to the output body 8.

[0070] The motor unit 3 may be built into the frame 10. When the motor unit 3 is built into the frame 10, it may be positioned across multiple members that make up the frame 10 (for example, the standpipe 104 and the chain stay 106).

[0071] The first gear pair 91 may include face gears.

[0072] The first gear pair 91 may include hypoid gears.

[0073] The first gear pair 91 may include screw gears.

[0074] Next, a modified example will be described, as shown in Fig. 7. This modified example is an example in which the main difference is the state in which the battery 15 is attached to the frame 10 of the electric bicycle 1 of the first or second embodiment.

[0075] In this modification, the down pipe 103 is bent so that the middle portion thereof is convex downward, and has a front portion 1031 in front of the bent portion and a rear portion 1032 behind the bent portion. The battery 15 is mounted to the frame 10 by being housed in the front portion 1031.

[0076] When the battery 15 is mounted on the frame 10, a first imaginary line 510 extending in the axial direction of the central axis of the motor rotating shaft 51 intersects with a second imaginary line 150 extending in the longitudinal direction of the battery 15. The first imaginary line 510 extending in the axial direction of the central axis of the motor rotating shaft 51 is aligned with the longitudinal direction of the rear portion 1032. The second imaginary line 150 extending in the longitudinal direction of the battery 15 is aligned with the longitudinal direction of the front portion 1031.

[0077] The point where the first virtual line 510 and the second virtual line 150 intersect (a point around the bend in the lower pipe 103) is the intersection of the first virtual line 510 extending from the motor rotation shaft 51 and the second virtual line 150 extending from the battery 15, and the battery 15 and the motor 5 (motor unit 3) are not located at this intersection.

[0078] The battery 15 is housed in the front part 1031 through an opening (not shown) formed in the rear part 1032. More specifically, an opening through which the battery 15 can be inserted is formed at a portion of the rear part 1032 where it intersects with the second imaginary line 150, and a lid (not shown) is removably attached to this opening. The battery 15 is inserted forward into the front part 1031 through the opening in the rear part 1032 with the lid removed, and after insertion, the lid is attached to the opening. The terminals of the battery 15 inserted into the front part 1031 are electrically connected to battery terminals of the battery mounting part 16.

[0079] In this modified example, the motor 5 (motor unit 3) is not located on the second imaginary line 150. Therefore, when removing the battery 15 by moving it along the longitudinal direction of the front part 1031, there are no obstacles such as the motor 5 (motor unit 3) on the line of movement (i.e., on the second imaginary line 150), making it easy to remove the battery 15 from the frame 10. In addition, it is easy to make the frame 10 smaller.

[0080] Next, a modified example shown in Fig. 8 will be described. This modified example is a further modified example of the modified example shown in Fig. 7, and since most of the configuration is the same as the modified example shown in Fig. 7, only the configuration that differs from the modified example shown in Fig. 7 will be described.

[0081] This modified example is an example in which the upper pipe 102 is omitted from the modified example shown in FIG. 7. In the electric bicycle 1 of this modified example, the upper pipe 102 is not provided, so when mounting the electric bicycle 1 from a non-ridden state, there is no need to pass one's feet over the upper pipe 102 or behind the rear wheel 112, making it easier to ride the electric bicycle 1. Also, as with the modified example shown in FIG. 7, the motor 5 (motor unit 3) is not located on the second imaginary line 150. Therefore, when removing the battery 15 by moving it along the longitudinal direction of the front part 1031, there is no obstacle such as the motor 5 (motor unit 3) on the line of movement (i.e., on the second imaginary line 150), making it easy to remove the battery 15 from the frame 10. Also, it is easy to reduce the size of the frame 10.

[0082] Next, a modified example will be described, as shown in Fig. 9. This modified example is an example in which the main difference is the state in which the battery 15 is attached to the frame 10 in the electric bicycle 1 of the first or second embodiment.

[0083] 7 and 8, the down pipe 103 in this modification is not bent as in the embodiment shown in FIG. 1 but is formed straight. The battery 15 is mounted to the frame 10 by being housed in the down pipe 103. A first imaginary line 510 extending in the axial direction of the central axis of the motor rotating shaft 51 and a second imaginary line 150 extending in the longitudinal direction of the battery 15 are aligned along the longitudinal direction of the down pipe 103.

[0084] In this modification, when viewed from the direction of the axis 600 of the input shaft 6, a first imaginary line 510 extending in the axial direction of the central axis of the motor rotary shaft 51 overlaps with the battery 15. Furthermore, the first imaginary line 510 is parallel to the second imaginary line 150.

[0085] In this modified example, the motor rotation shaft 51 and the battery 15 can be easily arranged on substantially the same straight line, and the frame 10 can be easily made smaller.

[0086] Next, a modified example shown in Fig. 10 will be described. This modified example is a further modified example of the modified example shown in Fig. 9, and since most of the configuration is the same as the modified example shown in Fig. 9, only the configuration that differs from the modified example shown in Fig. 9 will be described.

[0087] In this modification, the battery 15 is mounted on the frame 10 by being housed in a straight standpipe 104. A first imaginary line 510 extending in the axial direction of the central axis of the motor rotating shaft 51 and a second imaginary line 150 extending in the longitudinal direction of the battery 15 are aligned along the longitudinal direction of the standpipe 104.

[0088] 9 , in this modification, when viewed from the direction of the axis 600 of the input shaft 6, a first imaginary line 510 extending in the axial direction of the central axis of the motor rotating shaft 51 overlaps with the battery 15. Furthermore, the first imaginary line 510 is aligned with the second imaginary line 150.

[0089] In this modification, similar to the modification shown in FIG. 9, the motor rotating shaft 51 and the battery 15 can be easily arranged on a substantially straight line, and the frame 10 can be easily made smaller.

[0090] Next, a modified example shown in Fig. 11 will be described. This modified example is a further modified example of the modified example shown in Fig. 10, and since most of the configuration is the same as the modified example shown in Fig. 10, only the configuration that differs from the modified example shown in Fig. 10 will be described.

[0091] In this modified example, the battery 15 is mounted to the frame 10 by being attached to the rear side of the straight standpipe 104. A first imaginary line 510 extending in the axial direction of the central axis of the motor rotating shaft 51 and a second imaginary line 150 extending in the longitudinal direction of the battery 15 are aligned along the longitudinal direction of the standpipe 104. In other words, when viewed from the direction of the axis 600 of the input shaft 6, the first imaginary line 510 is parallel to the second imaginary line 150, but the first imaginary line 510 and the second imaginary line 150 are not on the same straight line but are offset from each other in parallel.

[0092] In this modified example, the first imaginary line 510 and the second imaginary line 150 are parallel to each other, so that the frame 10 can be easily formed linearly, which makes it easier to improve the rigidity of the frame 10.

[0093] Next, a modified example shown in Fig. 12 will be described. This modified example is a further modified example of the modified example shown in Fig. 11, and since most of the configuration is the same as the modified example shown in Fig. 11, only the configuration that differs from the modified example shown in Fig. 11 will be described.

[0094] 11, the battery 15 is attached to the frame 10 by being attached to the rear side of the stand pipe 104, whereas in this modification, the battery 15 is attached to the front side of the straight stand pipe 104. A first imaginary line 510 extending in the axial direction of the central axis of the motor rotating shaft 51 and a second imaginary line 150 extending in the longitudinal direction of the battery 15 are aligned along the longitudinal direction of the stand pipe 104. In other words, when viewed from the direction of the axis 600 of the input shaft 6, the first imaginary line 510 is parallel to the second imaginary line 150, but the first imaginary line 510 and the second imaginary line 150 are not on the same straight line but are offset from each other.

[0095] In this modified example, as with the modified example shown in Figure 11, the first virtual line 510 and the second virtual line 150 are parallel to each other, making it easier to form the frame 10 in a straight line, which makes it easier to improve the rigidity of the frame 10.

[0096] As is clear from the above-described embodiment and its modified examples, the motor unit 3 of the first aspect includes a case 4, a motor 5 housed in the case 4 and having a motor rotating shaft 51 and a rotor 52 rotating integrally with the motor rotating shaft 51, an input shaft 6, an output body 8, and a reduction mechanism 9. The input shaft 6 passes through the case 4 in the direction of an axis 600 and is arranged to be rotatable about the axis 600. The output body 8 passes through the case 4 in the direction of the axis 600 and is arranged to be rotatable about the axis 600. 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 a plurality of pairs of gears that mesh with each other. At least one pair of the plurality of gear pairs has central axes of rotation of the gears that are perpendicular to each other.

[0097] According to the first aspect, it is easy to shorten the length of the motor 5 and the reduction mechanism 9 arranged inside the case 4 in the direction of the axis 600, and it is easy to reduce the width of the case 4 and make the case 4 more compact.

[0098] The second aspect can be realized by combining the first aspect. In the second aspect, the speed reduction mechanism 9 has two gear pairs, a first gear pair 91 and a second gear pair 92. The central axes of the first gear 911 and the second gear 912 that make up the first gear pair 91 are perpendicular to each other. The central axes of the third gear 921 and the fourth gear 922 that make up the second gear pair 92 are parallel to each other.

[0099] According to the second aspect, the width of the case 4 can be reduced, making it easier to make the case 4 smaller.

[0100] The third aspect can be realized by combining with the second aspect. In the third aspect, the first gear pair 91 has the central axes of the first gear 911 and the second gear 912 intersecting each other.

[0101] According to the third aspect, it is easy to achieve miniaturization, improvement in transmission efficiency, and improvement in assembly.

[0102] The fourth embodiment can be realized by combining with the second embodiment. In the fourth embodiment, the central axes of the first gear 911 and the second gear 912 of the first gear pair 91 do not intersect.

[0103] According to the fourth aspect, it is easy to obtain a large reduction ratio.

[0104] The fifth aspect can be realized by combining with the fourth aspect. In the fifth aspect, the first gear pair 91 is a hypoid gear or a spiral bevel gear.

[0105] According to the fifth aspect, the width of the case 4 can be reduced, making it easier to make the case 4 smaller.

[0106] The sixth aspect can be realized by combining with any one of the second to fifth aspects. In the sixth aspect, the reduction gear mechanism 9 has a transmission rotation shaft 310, and the first gear pair 91 is composed of a first gear 911 that rotates integrally with the motor rotation shaft 51 and a second gear 912 that is arranged on the transmission rotation shaft 310, and the second gear pair 92 is composed of a third gear 921 that is arranged on the transmission rotation shaft 310 and a fourth gear 922 that rotates integrally with the output body 8.

[0107] According to the sixth aspect, the width of the case 4 can be reduced, making it easier to make the case 4 smaller.

[0108] The seventh aspect can be realized by combining the first or second aspect. In the seventh aspect, the rotation speed of the input shaft 6 and the rotation speed of the output body 8 are configured to match.

[0109] According to the seventh embodiment, the phase of rotation of the input shaft 6 and the output body 8 about the axis 600 is fixed.

[0110] The eighth aspect can be realized by combining the first or second aspect. In the eighth aspect, a one-way clutch 316 is provided between the speed reduction mechanism 9 and the output body 8. The central axis of rotation of the one-way clutch 316 is located on the axis 600.

[0111] According to the eighth aspect, there is no need to place the one-way clutch 316 in a portion of the case 4 away from the input shaft 6 and the output body 8, making it easier to create space in a portion of the case 4 away from the input shaft 6 and the output body 8.

[0112] The electric bicycle 1 of the ninth aspect is equipped with any one of the first to eighth motor units 3.

[0113] According to the ninth aspect, the width of the case 4 can be reduced, making it easier to make the electric bicycle 1 compact.

[0114] The tenth aspect can be realized by combining it with the sixth aspect. The tenth aspect includes the motor unit 3 of the sixth aspect, a frame 10, and a battery 15 mounted on the frame 10. When viewed from the direction of the axis 600 of the input shaft 6, a first imaginary line 510 extending in the axial direction of the central axis of the motor rotating shaft 51 overlaps with the battery 15.

[0115] According to the tenth aspect, the motor rotating shaft 51 and the battery 15 can be easily arranged on substantially the same straight line, and the frame 10 can be easily made smaller.

[0116] The eleventh aspect can be realized by combining it with the sixth aspect. The eleventh aspect includes the motor unit 3 of the sixth aspect, a frame 10, and a battery 15 mounted on the frame 10. When viewed from the direction of the axis 600 of the input shaft 6, a second imaginary line 150 extending in the longitudinal direction of the battery 15 and a first imaginary line 510 extending in the axial direction of the central axis of the motor rotating shaft 51 are parallel to each other.

[0117] According to the eleventh aspect, the first imaginary line 510 and the second imaginary line 150 are parallel to each other, so that the frame 10 can be easily formed linearly, and thus the rigidity of the frame 10 can be easily improved.

[0118] The twelfth aspect can be realized by combining it with any one of the first to eighth aspects. The twelfth aspect includes the motor unit 3 of any one of the first to eighth aspects, a frame 10, and a battery 15 mounted on the frame 10. When viewed from the direction of the axis 600 of the input shaft 6, a first imaginary line 510 extending in the axial direction of the central axis of the motor rotating shaft 51 and a second imaginary line 150 extending in the longitudinal direction of the battery 15 intersect.

[0119] According to the 12th aspect, the motor 5 (motor unit 3) is not positioned on the second virtual line 150, so that when the battery 15 is moved along the longitudinal direction of the frame 10 to be removed, there are no obstacles such as the motor 5 (motor unit 3) on the movement path (i.e., on the second virtual line 150), making it possible to easily remove the battery 15 from the frame 10.

[0120] The thirteenth aspect can be realized by combining with the twelfth aspect. In the thirteenth aspect, the first virtual line and the second virtual line intersect on the frame 10.

[0121] According to the thirteenth aspect, the frame 10 can be easily made smaller. [Explanation of symbols]

[0122] 1. Electric bicycle 10 frames 15 Battery 150 Second Virtual Line 3 Motor Unit 31 Reduction mechanism 310 Transmission Rotating Shaft 4 cases 5 motors 51 Motor rotating shaft 510 First Virtual Line 52 rotor 6 Input shaft 600 axis 8 Output Body 91 1st gear pair 911 1st gear 912 2nd gear 92 2nd gear pair 921 3rd gear 922 4th Gear

Claims

1. A case having a first divided body and a second divided body, and having an internal storage space in which the interior of the first divided body and the interior of the second divided body are continuous; a motor housed in the case and having a motor rotating shaft and a rotor that rotates integrally with the motor rotating shaft; an input shaft that passes through the case in an axial direction and is arranged to be rotatable about the axis; an output body that penetrates the case in the axial direction and is arranged to be rotatable around the 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 rotation detection unit having a rotor provided on the input shaft and detecting rotation of the input shaft; a substrate accommodated in the case; Equipped with a first bearing that rotatably supports the input shaft is disposed in the first divided body; a second bearing that rotatably supports the output body is disposed in the second divided body, The reduction mechanism and the substrate are accommodated in the accommodation space, the reduction mechanism has a plurality of gear pairs that mesh with each other, and at least one of the plurality of gear pairs has central axes of rotation that are perpendicular to each other; one gear pair of the plurality of gear pairs includes a gear pair constituted by one gear and another gear that meshes with the one gear and rotates integrally with the output body, the central axis of the motor rotation shaft is oriented in a direction perpendicular to the axial direction, The substrate is provided on the first bearing side of the other gear in the axial direction of the input shaft and on the second bearing side of the rotating body. Motor unit.

2. When viewed from the axial direction of the input shaft, the base plate and the other gear overlap. The motor unit according to claim 1 .

3. When viewed from the axial direction of the input shaft, the output body and the substrate overlap. The motor unit according to claim 2 .

4. The diameter of the rotating body is larger than the diameters of the first bearing and the second bearing. The motor unit according to claim 3 .

5. At least one pair of the plurality of gear pairs includes a first gear whose rotation axis is parallel to the motor rotation axis, When viewed from the axial direction of the input shaft, the another gear and the first gear overlap each other. The motor unit according to claim 4.

6. A motor unit according to any one of claims 1 to 5 is provided. Electric bicycle.

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