JP2020090227A - Motor unit, motor unit body and electric bicycle - Google Patents

Abstract

To provide a motor unit which is improved in lubrication performance and accordingly can be downsized, and a motor unit body and an electric bicycle.SOLUTION: A motor unit 2 is used for an electric bicycle which can run by adding drive auxiliary output generated by a motor to man-power driving force. The motor unit 2 comprises a housing 21, a motor, an output body 33, a gear 44, and oil 54. The motor is mounted on the housing 21. The output body 33 outputs drive auxiliary output from the motor. The gear 44 transmits the drive auxiliary output output from the motor 36 to the output body 33, and is housed in the housing 21. The oil 54 is stored in the housing 21 and performs oil lubrication on the gear 44. In the motor unit 2, at least part of the gear 44 is soaked in the oil 54 while the rotary shaft of the output body 33 is along a horizontal surface.SELECTED DRAWING: Figure 4

Description

The present invention relates to a motor unit, a motor unit body, and an electric bicycle.

Patent Document 1 discloses a conventional motor drive unit. The motor drive unit described in Patent Document 1 includes a unit case (housing), a crankshaft penetrating the unit case, a motor, an interlocking body (output body), and deceleration for transmitting an output from the motor to the interlocking body. And a gear for gear (gear). The output shaft of the motor is inside the unit case, and the reduction gear that meshes with the output shaft is also inside the unit case. A drive sprocket is attached to the interlocking body, and a drive auxiliary output can be output to the rear wheels.

In the motor drive unit described in Patent Document 1, at the time of operation, between the reduction gear and the output shaft meshed therewith, between the reduction gear and the tooth portion (large diameter gear portion) of the interlocking body meshed with the reduction gear. Can generate frictional heat. Grease is applied to the gears and gears for the purpose of reducing this frictional heat.

International publication 2014/184826

However, in a conventional motor unit that is lubricated with grease, the viscosity of the grease is high, so that the tooth width of the gear needs to be a certain value or more in order to prevent damage to the teeth of the gear. Therefore, the conventional motor unit is disadvantageous in aiming for miniaturization.

An object of the present invention is to provide a motor unit, a motor unit body, and an electric bicycle that have improved lubrication performance and can be downsized.

A motor unit according to one aspect of the present invention is a motor unit used for an electric bicycle that is capable of traveling by adding a driving assist output generated by a motor to a human-powered driving force. The motor unit includes a housing, a motor, an output body, a gear, and oil. The motor is attached to the housing. The output body outputs the drive assist output from the motor. The gear transmits the drive auxiliary output output from the motor to the output body, and is housed in the housing. The oil is stored in the casing and lubricates the gear with oil. In the motor unit, at least a part of the gear is submerged in the oil with the rotation axis of the output body along a horizontal plane.

A motor unit main body according to one aspect of the present invention is a motor unit main body used for an electric bicycle that is capable of traveling by adding a driving assist output generated by a motor to a human-powered driving force. The motor unit main body includes a housing, a motor, an output body, and a gear. The motor is attached to the housing. The output body outputs the drive assist output from the motor. The gear transmits the drive auxiliary output output from the motor to the output body, and is housed in the housing. The casing has an oil injection port for injecting oil for lubricating the gear into the casing.

An electric bicycle according to one aspect of the present invention includes a frame, the above-described motor unit attached to the frame, a plurality of wheels, and a power transmission body. The plurality of wheels are attached to the frame. The power transmission body transmits the power output from the motor unit to at least one of the plurality of wheels.

An electric bicycle according to one aspect of the present invention includes a frame, the above-described motor unit main body attached to the frame, a plurality of wheels, and a power transmission body. The plurality of wheels are attached to the frame. The power transmission body transmits the power output from the motor unit main body to at least one of the plurality of wheels.

The motor unit, the motor unit main body, and the electric bicycle according to the above aspect of the present invention have the advantages that the lubrication performance can be improved and the size can be reduced.

1 is a side view of an electric bicycle according to a first embodiment of the present invention. FIG. 2 is a sectional view of a motor unit of the above electric bicycle. FIG. 3 is an enlarged view of portion A of FIG. FIG. 4 is a vertical sectional view of the above motor unit. FIG. 5 is a cross-sectional view of essential parts of a motor unit according to Modification 1. FIG. 6A is a side view of a gear of a motor unit according to Modification 2. 6B is a cross-sectional view taken along the line AA of FIG. 6A. FIG. 7A is a cross-sectional view of essential parts of a motor unit according to Modification 3. FIG. 7B is a cross-sectional view of essential parts of a motor unit according to a further modification of Modification 3. FIG. 8 is a cross-sectional view of a motor unit according to Modification 4. FIG. 9A is a vertical cross-sectional view of a motor unit according to Modification 4. FIG. 9B is a vertical cross-sectional view of a motor unit according to another modification of Modification 4. FIG. 10 is a front view of a motor unit of a further modified example.

(1) Embodiment (1.1) Outline The motor unit 2 according to the present embodiment is used, for example, in an electric bicycle 1 as shown in FIG. The electric bicycle 1 is a bicycle that can run by adding a driving assist output generated by the motor 36 to the human-powered driving force. As shown in FIG. 2, the motor unit 2 includes a housing 21, a motor 36, an output body 33, and a gear 44. The “driving auxiliary output” as referred to in the present disclosure means a rotation output given to the wheels 65 and 66 by the motor 36.

The motor 36 is attached to the housing 21. At least a part of the output shaft 39 of the motor 36 is located inside the housing 21. The output body 33 outputs the drive auxiliary output from the motor 36. In this embodiment, for example, a drive sprocket 35 is attached to the output body 33.

The gear 44 transmits the drive assist output output from the motor 36 to the output body 33. The gear 44 fits inside the housing 21. In the present embodiment, the gear 44 meshes with the output shaft 39 of the motor 36 and transmits the drive assist output to the output body 33.

The motor unit 2 according to the present embodiment includes oil 54, as shown in FIG. The oil 54 is stored in the housing 21. The oil 54 lubricates the gear 44 with oil. In the motor unit 2 according to the present embodiment, at least a part of the gear 44 is immersed in the oil 54 with the rotation axis of the output body 33 extending along the horizontal plane.

Therefore, according to the motor unit 2 of the present embodiment, the gear 44 can be constantly oil-lubricated, the lubricating performance of the motor unit 2 can be improved, and the miniaturization can be realized.

(1.2) Details Hereinafter, the electric bicycle 1 and the motor unit 2 according to the present embodiment will be described in detail. Hereinafter, the traveling surface 100 will be described as a horizontal surface unless otherwise specified. However, in reality, the traveling surface 100 does not have to be a horizontal plane, and may be inclined with respect to the horizontal plane or may be a surface having irregularities. In the present disclosure, the direction in which the electric bicycle 1 travels may be referred to as the “front direction”, the opposite direction to the front direction may be referred to as the “rear direction”, and the front direction and the rear direction may be collectively referred to as the “front and rear direction”. Further, two directions that are orthogonal to the front-rear direction and are opposite to each other along the horizontal plane are defined as "left-right direction".

However, the definition of these directions is not intended to limit the usage of the electric bicycle 1 and the motor unit 2. Further, the arrows indicating the respective directions in the drawings are shown for the sake of explanation only and do not have substance.

(1.2.1) Overall Configuration The electric bicycle 1 is a bicycle that can travel on the traveling surface 100 by the power output from the motor 36 (see FIG. 2). In the present embodiment, the electric bicycle 1 is an electric assist bicycle including a motor unit 2 as shown in FIG.

The “electrically assisted bicycle” as referred to in the present disclosure means a bicycle having a motor unit 2 that supplements the stepping force of the driver (hereinafter referred to as “pedaling force”) by a drive assist output. Therefore, the “electrically assisted bicycle” in the present disclosure includes not only the electrically assisted bicycle in accordance with the regulations but also the bicycle having the motor unit 2 which does not belong to the electrically assisted bicycle in accordance with the regulations.

The electric bicycle 1 is an electrically assisted bicycle in this embodiment. However, in the present disclosure, a bicycle in which a drive system (human power drive system) that gives power to the wheels by pedaling force and a drive system (motor 36 drive system) that gives power to the wheels by the motor 36 are independent (even with the motor 36 alone). It can be a bicycle that can run. In short, the electric bicycle 1 according to the present disclosure may be an electrically assisted bicycle or a bicycle that can travel only with the power output from the motor 36.

As shown in FIG. 1, the electric bicycle 1 includes a front fork 6, a handle 64, a plurality of (here, two) wheels 65 and 66, a frame 7, a saddle 91, a pair of crank arms 92, a pair of pedals 93, a power source. The transmission body 8, the battery 9 and the motor unit 2 are provided.

The plurality of wheels 65, 66 are members that support the frame 7 on the traveling surface 100. The electric bicycle 1 includes, as the plurality of wheels 65 and 66, at least one front wheel 65 and at least one rear wheel 66. The electric bicycle 1 according to the present embodiment includes one front wheel 65 and one rear wheel 66. However, the electric bicycle 1 according to the present disclosure includes one front wheel 65 and two rear wheels 66, or two front wheels 65. It may be a three-wheeled bicycle having a front wheel 65 and one rear wheel 66. Further, the electric bicycle 1 according to the present disclosure may be a four-wheel bicycle including two front wheels 65 and two rear wheels 66. Each of the plurality of wheels 65 and 66 according to the present embodiment has hubs 661 and 651 at the center.

The front fork 6 supports the front wheel 65. The front fork 6 includes a pair of legs 61, a crown 62 that connects the upper ends of the pair of legs 61, and a steering column 63 that projects from the crown 62. A front wheel 65 is rotatably attached to the pair of legs 61 via a shaft passed through a hub 651. The rotation axis of the front wheel 65 is parallel to the traveling surface 100, and is the same as the central axis of the shaft that supports the front wheel 65. The protruding direction (longitudinal direction) of the steering column 63 extends from the crown 62 so as to go rearward as it goes upward, and is inclined with respect to the traveling surface 100.

The handle 64 is attached to the upper end of the steering column 63 and is fixed to the front fork 6. The steering column 63 is passed through a head pipe 71 of the frame 7 described later and is rotatably attached to the frame 7. The rotation axis of the steering column 63 is substantially parallel to the longitudinal direction of the steering column 63. Therefore, the handle 64 can rotate the front wheels 65 with the axis along the longitudinal direction of the steering column 63 as the rotation axis.

The frame 7 is a frame to which the plurality of wheels 65, 66, the front fork 6, the handle 64, the saddle 91, the battery 9, and the motor unit 2 are attached. In the present embodiment, the frame 7 is made of an aluminum alloy containing aluminum as a main component. However, in the present disclosure, the frame 7 is not limited to the aluminum alloy, and may be made of, for example, iron, chrome molybdenum steel, high-tensile steel, titanium, magnesium, or the like. The frame 7 according to the present disclosure is not limited to metal, and may be made of carbon, wood, bamboo, fiber-reinforced synthetic resin (for example, CFRP; Carbon Fiber Reinforced Plastics), or the like.

The frame 7 according to the present embodiment includes a head pipe 71, an upper pipe 72, a lower pipe 74, a standing pipe 75, a plurality of (here, two) seat stays 76, a plurality (here, two) of chain stays 77, and a bracket. Equipped with 78. The "pipe" in the present disclosure means an elongated hollow member. The cross-sectional shape of the pipe according to the present disclosure may be, for example, a circular shape (including a perfect circle, an ellipse, and an ellipse), a rectangular shape (including a square), a hexagonal shape, an octagonal shape, or the like.

The head pipe 71 is a pipe that supports the front fork 6. The central axis of the head pipe 71 is inclined with respect to the traveling surface 100 so as to go backward as it goes upward. The steering column 63 is passed through the head pipe 71 so that the central axis of the head pipe 71 and the central axis of the steering column 63 are aligned. As a result, the head pipe 71 rotatably supports the steering column 63. The rotation axis of the steering column 63 is the same as the central axis of the head pipe 71 in this embodiment.

The upper pipe 72 connects the head pipe 71 and the standing pipe 75. The front end of the upper pipe 72 in the longitudinal direction is connected to the head pipe 71. The longitudinal pipe rear end of the upper pipe 72 is connected to the vertical pipe 75. In the present embodiment, the longitudinal direction of the upper pipe 72 is inclined with respect to the traveling surface 100 so as to go downward as it goes backward. However, in the present disclosure, the upper pipe 72 may not be inclined with respect to the traveling surface 100. The electric bicycle 1 according to the present disclosure may not include the upper pipe 72.

The electric bicycle 1 according to the present embodiment includes a reinforcing pipe 73 for reinforcing the connecting portion between the standing pipe 75 and the upper pipe 72. The reinforcing pipe 73 connects the standing pipe 75 and the upper pipe 72. In the present disclosure, the electric bicycle 1 may not include the reinforcing pipe 73.

The vertical pipe 75 holds the saddle 91. The lower end of the standing pipe 75 in the longitudinal direction is connected to the bracket 78. The central axis of the standing pipe 75 is inclined with respect to the traveling surface 100 so that it goes backward as it goes upward from the lower end. The rear end of the upper pipe 72 in the longitudinal direction is connected to the middle portion of the standing pipe 75. The “intermediate portion of the standing pipe 75” here means a portion of the standing pipe 75 in the longitudinal direction thereof excluding the lower end and the upper end. However, in the present disclosure, the upper pipe 72 may be connected to the upper end of the standing pipe 75.

A seat pillar 910 is passed through the standing pipe 75 along the central axis of the standing pipe 75. Here, the seat pillar 910 is included in the saddle 91. The seat pillar 910 projects downward from a portion of the saddle 91 where the driver sits. In the present embodiment, the seat pillar 910 is inclined with respect to the traveling surface 100 so as to move forward in the downward direction. The seat pillar 910 is attached to the standing pipe 75 so as to be movable along the central axis of the standing pipe 75.

The lower pipe 74 connects the bracket 78 and the head pipe 71. The front end of the lower pipe 74 in the longitudinal direction is connected to the head pipe 71. The rear end of the lower pipe 74 in the longitudinal direction is connected to the bracket 78. The central axis of the lower pipe 74 is inclined with respect to the horizontal plane so as to move upward from the rear end in the longitudinal direction toward the front. In this embodiment, the battery 9 is detachably attached to the lower pipe 74.

The plurality of chain stays 77 support the shaft of the rear wheel 66. The front end in the longitudinal direction of the chain stay 77 is connected to the bracket 78. The longitudinal rear end of the chain stay 77 is connected to the rear end of the seat stay 76. The pair of chain stays 77 are separated from each other in the left-right direction, and the rear wheels 66 are rotatably attached to the rear ends of the pair of chain stays 77 via a shaft passed through a hub 661. The rotation axis of the rear wheel 66 is substantially parallel to the traveling surface 100 and is the same as the central axis of the shaft that supports the rear wheel 66.

The rear wheel 66 according to the present embodiment includes a rear sprocket 662 that is concentric with the hub 661 and that is integrally attached to the hub 661. The rear sprocket 662 is connected to the drive sprocket 35 of the motor unit 2 described later via the power transmission body 8. Therefore, the rear wheel 66 rotates around the shaft by the output from the motor unit 2.

The plurality of seat stays 76 connect the chain stay 77 and the standing pipe 75. In the present embodiment, the longitudinal rear end of the seat stay 76 is connected to the longitudinal rear end of the chain stay 77. A front end in the longitudinal direction of the seat stay 76 is connected to an intermediate portion of the standing pipe 75. The pair of seat stays 76 according to the present embodiment is branched from the upper pipe 72 and is integral with the upper pipe 72. However, the seat stay 76 and the upper pipe 72 may be separate bodies.

The bracket 78 is a portion to which the motor unit 2 is attached. In the present embodiment, the bracket 78 is formed in a substantially C-shape when viewed from the side surface 443, and has a rear end in the longitudinal direction of the lower pipe 74, a lower end in the longitudinal direction of the standing pipe 75, and a front end in the longitudinal direction of the chain stay 77. It is connected. As a result, the rear end of the lower pipe 74 in the longitudinal direction, the lower end of the standing pipe 75 in the longitudinal direction, and the front end of the chain stay 77 in the longitudinal direction are fixed to each other.

The battery 9 supplies electric power to the motor unit 2. In addition, in the present embodiment, the battery 9 supplies electric power to, for example, a headlight, an ON/OFF operation unit of the motor 36, and the like in addition to the motor 36. In the present embodiment, the battery 9 is detachably attached to the lower pipe 74, but in the present disclosure, the battery 9 may be arranged behind the standing pipe 75 and along the standing pipe 75.

The motor unit 2 is a device capable of outputting a drive auxiliary output. In the present embodiment, the motor unit 2 adds a drive assist output to the pedal effort, which is a human-powered drive force, and transmits it to the rear wheel 66 via the power transmission body 8. The motor unit 2 is a uniaxial motor unit 2 in this embodiment. However, in the present disclosure, the motor unit 2 may be a biaxial motor unit 2a, as shown in Modification 4 described later. Details of the motor unit 2 will be described later in “(1.2.2) Motor unit”.

A pair of crank arms 92 is attached to the crank shaft 28 of the motor unit 2. The longitudinal direction of the crank arm 92 intersects with the rotation axis of the crank shaft 28 (here, it is orthogonal). The pair of crank arms 92 are aligned on a straight line when viewed in the rotation axis direction of the crankshaft 28.

The pedal 93 is attached to the end of each crank arm 92 in the longitudinal direction on the side opposite to the crankshaft 28 side. The pedal 93 is rotatably attached to the crank arm 92. The rotation axis of the pedal 93 is substantially parallel to the rotation axis of the crankshaft 28.

The power transmission body 8 transmits the power output from the motor unit 2 to at least one of the wheels 65 and 66. In the present embodiment, the power transmission body 8 is a chain that is hung between the drive sprocket 35 of the motor unit 2 and the rear sprocket 662 of the rear wheel 66 so that power can be transmitted. However, in the present disclosure, the power transmission body 8 may be, for example, a belt, a shaft, a wire, a gear, or the like.

(1.2.2) Motor Unit The motor unit 2 is a device capable of outputting the drive auxiliary output as described above. In the motor unit 2, when the driver pedals the pedal 93 and a pedaling force (manual driving force) is input to the crank shaft 28 via the crank arm 92, the crank shaft 28 rotates. When the crankshaft 28 receives a pedaling force and rotates, the motor unit 2 according to the present embodiment detects the rotation speed of the crankshaft 28 and the torque generated in the crankshaft 28, and outputs an assisting force according to the detection result. The motor unit 2 includes a motor unit main body 20 and oil 54 (see FIG. 4) stored inside the motor unit main body 20.

(1.2.2.1) Motor Unit Main Body The motor unit main body 20 has a configuration in which the oil 54 is removed from the motor unit 2, and only the motor unit main body 20 drives the assist force (here, the driving force is driven manually). It is possible to output the resultant force including the auxiliary output). As shown in FIG. 2, the motor unit main body 20 includes a housing 21, a crankshaft 28, a rotating body 29, an output body 33, a drive sprocket 35, a motor 36, a reduction mechanism 41, and a control board 45.

The housing 21 is a hollow body that houses the rotating body 29, the reduction mechanism 41, and the control board 45. The housing 21 is made of metal in the present embodiment. Examples of the metal forming the housing 21 include aluminum alloy, stainless steel, steel and the like. However, in the present disclosure, the housing 21 is not limited to metal, and may be made of carbon, wood, bamboo, fiber-reinforced synthetic resin (for example, CFRP), or the like. The housing 21 is formed, for example, by casting, and more specifically, is formed by die casting. The housing 21 includes a first divided body 22 and a second divided body 23. The first divided body 22 and the second divided body 23 are arranged side by side in the left-right direction.

The first divided body 22 is formed in a bottomed tubular shape having an opening surface on the right side (second divided body 23 side). The first divided body 22 has a first side wall 221, and a first peripheral wall 225 protruding rightward from the peripheral edge of the first side wall 221. The first side wall 221 has a first surface 222 facing the outside (left direction) of the housing 21, and a second surface 223 facing the inside of the housing 21. The motor 36 is attached to the first surface 222 of the first side wall 221.

The first peripheral wall 225 has a first mating surface 226. In the present embodiment, the first mating surface 226 is located on a vertical plane. The first mating surface 226 faces to the right in the present embodiment. In short, the first mating surface 226 faces the second divided body 23 side.

The second divided body 23 is formed in a bottomed tubular shape having an opening surface on the left side (first divided body 22 side). The second divided body 23 has a second side wall 231, and a second peripheral wall 235 protruding leftward from the peripheral edge of the second side wall 231. The second side wall 231 has a first surface 232 facing the outside (rightward direction) of the housing 21, and a second surface 233 facing the inside of the housing 21.

The second peripheral wall 235 has a second mating surface 236. In the present embodiment, the second mating surface 236 is located on a vertical plane. The second mating surface 236 faces to the left in this embodiment. In short, the second mating surface 236 faces the first divided body 22 side.

In the first divided body 22 and the second divided body 23, the first mating surface 226 and the second mating surface 236 face each other, and a seal (not shown) is provided between the first mating surface 226 and the second mating surface 236. ) Are clamped together, and they are fixed to each other by a fastener (for example, a bolt).

The “seal” mentioned here includes a seal for preventing foreign matter from entering from the outside to the inside of the housing 21, and a seal for suppressing leakage of the oil 54 stored in the housing 21 as described later.

Examples of the “seal” in the present disclosure include gaskets, packings, labyrinth seals, and the like. Examples of the gasket include a soft gasket and a metal gasket. Examples of the packing include squeeze packing (O-ring, X-ring, T-ring, etc.), squeeze packing, lip packing, oil seal, mechanical seal, gland packing, and the like. In practice, a seal used for a stationary surface and a seal used for a moving surface can be appropriately used, but in the present disclosure, both a seal used for a stationary surface and a seal used for a moving surface are referred to as “seals. ".

The housing 21 includes a pressure adjusting unit 210. The pressure adjusting unit 210 moderates the pressure increase or pressure decrease of the gas existing in the housing 21. In short, the housing 21 exerts the breather function by the pressure adjusting unit 210. In the present embodiment, the pressure adjusting unit 210 is an L-shaped tube that allows the inside and the outside of the housing 21 to pass therethrough. However, the pressure adjusting unit 210 is not limited to the L-shaped tube, but a hole may be formed in a part of the housing 21 to allow the inside and outside of the housing 21 to pass therethrough, and the hole may be closed with a seal. As a result, when a pressure fluctuation occurs in the housing 21, intake or exhaust is performed from the hole according to the fluctuation, and the pressure in the housing 21 is adjusted.

The crankshaft 28 is a shaft that rotates by receiving human power (pedal force) that is an external force. The rotation axis of the crankshaft 28 is substantially parallel to the traveling surface 100, extends in the left-right direction in the present embodiment, and is the same as the central axis of the crankshaft 28. The crankshaft 28 is passed through a hole 224 formed in the first side wall 221 and a hole 234 formed in the second side wall 231, and penetrates the housing 21 in the left-right direction.

As shown in FIG. 3, the crankshaft 28 includes a bearing 46 a attached to the first divided body 22 and a bearing 46 b provided between the inner peripheral surface of the rotating body 29 and the crankshaft 28, and is a casing. 21 is rotatably attached.

Examples of the "bearings" in the present disclosure include rolling bearings, sliding bearings, fluid bearings, and the like. Examples of rolling bearings include ball bearings and roller bearings. The bearing is properly used depending on the shape, application, motion characteristics, etc. of the rotating object to be supported. In the present embodiment, both the bearings 46a and 46b that support the crankshaft 28 are rolling bearings.

As shown in FIG. 2, both ends of the crankshaft 28 in the longitudinal direction protrude from the housing 21. A crank arm 92 is attached to each of both ends of the crank shaft 28. The crank arm 92 is fixed to the crank shaft 28, and when the driver pedals the pedal 93, the crank arm 92 transmits rotational power to the crank shaft 28.

The rotating body 29 transmits the rotational power of the crankshaft 28 to the output body 33. As shown in FIG. 3, the rotating body 29 is arranged concentrically with the crankshaft 28 and rotates together with the crankshaft 28. The rotation axis of the rotating body 29 coincides with the rotation axis of the crankshaft 28. The rotating body 29 includes a transmission member 30, a one-way clutch 31, and a torque sensor 32.

The torque sensor 32 detects the torque of the crankshaft 28. The torque sensor 32 is a magnetostrictive torque sensor in this embodiment. The torque sensor 32 is attached along the outer periphery of the first member 301 of the transmission member 30. In the present embodiment, the torque sensor 32 detects the torque of the crankshaft 28 by detecting the torque of the first member 301. As the torque sensor 32, for example, a planetary gear mechanism and a potentiometer may be used to detect the torque of the crankshaft 28.

The transmission member 30 is formed in a tubular shape, and the crankshaft 28 is passed along the central axis of the transmission member 30. The transmission member 30 and the output body 33 are aligned in the axial direction of the crankshaft 28, and the one-way clutch 31 is attached between the transmission member 30 and the output body 33. The transmission member 30 is coupled to the crankshaft 28, and the rotational power of the crankshaft 28 is transmitted to the transmission member 30, the one-way clutch 31, and the output body 33 in this order. The transmission member 30 is composed of a first member 301 and a second member 303. The inner peripheral surface of the first member 301 and the outer peripheral surface of the crankshaft 28 are joined together. The connection between the first member 301 and the crankshaft 28 is realized by, for example, spline connection, key groove-key connection, wedge connection, fitting connection, screw connection, or the like.

The “spline connection” in the present disclosure includes, for example, connection by a square spline, an involute spline, a ball spline, a triangular mountain serration, an involute serration, or the like.

The second member 303 is aligned with the first member 301 in the axial direction of the crankshaft 28. The second member 303 has a fitting portion 304. The fitting portion 304 according to the present embodiment is formed on the inner peripheral surface of the left end portion of the second member 303. The first member 301 has a fitted portion 302. The fitted portion 302 according to the present embodiment is formed on the outer peripheral surface of the right end portion of the first member 301. The fitting part 304 and the fitted part 302 are coupled to each other. The coupling between the fitting portion 304 and the fitted portion 302 is spline coupling. However, the first member 301 and the second member 303 are not limited to the spline connection, but may be, for example, a key groove-key connection, a wedge connection, a fitting connection, a screw connection, or the like. As a result, the second member 303 rotates together with the first member 301.

The one-way clutch 31 is arranged between the second member 303 and the output body 33. Here, the left end portion of the output body 33 is located outside the right end portion of the second member 303 in the direction (radial direction) orthogonal to the axial direction of the crankshaft 28. The one-way clutch 31 is arranged between the left end of the output body 33 and the right end of the second member 303.

The one-way clutch 31 is, for example, a ratchet type one-way clutch. The one-way clutch 31 only allows transmission of rotational power from the second member 303 to the output body 33 when the output body 33 rotates in one direction. The “one direction” here is the direction of rotation of the output body 33 when the electric bicycle 1 is moved forward. The rotation axis of the output body 33 is the same as the rotation axis of the crankshaft 28 in this embodiment.

Specifically, the one-way clutch 31 shifts from the second member 303 to the output body 33 when the rotation speed of the second member 303 is faster than the rotation speed of the output body 33 when the electric bicycle 1 moves forward. The rotational power is transmitted to it. On the other hand, when the rotation speed of the second member 303 is lower than the rotation speed of the output body 33 when the electric bicycle 1 moves forward, the one-way clutch 31 causes the output body 33 to move to the second member 303. Does not transmit rotational power.

As a result, even when the driver stops pedaling the pedal 93 (see FIG. 1) when the output body 33 is rotated by the rotational power output from the motor 36 (see FIG. 2), the rotation of the output body 33 is prevented. Thus, the crankshaft 28 can be prevented from continuing to rotate.

The output body 33 outputs the rotational power output from the motor 36 to the outside of the housing 21. Since the motor unit 2 according to the present embodiment is the uniaxial motor unit 2 as described above, the output body 33 is rotated by the pedaling force input to the crankshaft 28 in addition to the rotational power output from the motor 36. Power is also transmitted. Therefore, in the motor unit 2 according to the present embodiment, the output body 33 outputs the rotational power that is a combination of the rotational power output from the motor 36 and the rotational power input to the crankshaft 28 to the outside of the housing 21. Output to.

As described above, the left end portion of the output body 33 is located outside the crankshaft 28 in the radial direction with respect to the second member 303. As shown in FIG. 2, the left end portion of the output body 33 has an output body tooth portion 331 that meshes with a gear 44 of a reduction mechanism 41 described later. The right end of the output body 33 penetrates the second side wall 231 of the second divided body 23 and projects rightward from the second side wall 231 of the second divided body 23. A drive sprocket 35 is attached to the right end of the output body 33. The drive sprocket 35 is fixed to the output body 33.

The pedaling force (external force) input to the crankshaft 28 by the driver pedaling the pedal 93 rotates the crankshaft 28 and is transmitted in the order of the first member 301, the second member 303, the one-way clutch 31, and the output body 33, The drive sprocket 35 is rotated. The rotation axis of the drive sprocket 35 is the same as the rotation axis of the crankshaft 28.

The motor 36 is an electric motor that can output rotational power. The motor 36 is attached to the housing 21. In the present embodiment, the motor 36 is attached to the first surface 222 of the first side wall 221 of the first divided body 22 of the housing 21, but in the present disclosure, the motor 36 is the first divided body 22 of the first divided body 22. It may be attached to the two faces 223. In short, the motor 36 may be mounted so as to fit inside the housing 21. The motor 36 has a stator 37, a rotor 38, and an output shaft 39.

The central axis of the output shaft 39 extends in the left-right direction. The rotation axis of the output shaft 39 is the same as the center axis of the output shaft 39, and is substantially parallel to the rotation axis of the crankshaft 28. The output shaft 39 includes a bearing 46e attached to the first divided body 22 and a bearing 46f attached to the second divided body 23, and is rotatably attached to the housing 21. The output shaft 39 is fixed to the rotor 38 while penetrating in the left-right direction.

The rotor 38 rotates along the inner peripheral surface of the stator 37. The rotation axis of the rotor 38 is the same as the rotation axis of the output shaft 39. A stator 37 is arranged around the rotor 38.

The stator 37 rotates the rotor 38. The stator 37 is attached to the motor cup 40 and is fixed to the motor cup 40. Examples of the stator 37 include a distributed winding stator, a concentrated winding stator, an inductor type stator, a permanent magnet type stator, and the like.

A tooth portion 391 having a plurality of teeth is formed on a portion of the output shaft 39 protruding from the rotor 38. The longitudinal direction of the tooth trace of the tooth portion 391 of the output shaft 39 is substantially parallel to the rotation axis of the output shaft 39 in the present embodiment.

The speed reduction mechanism 41 is housed inside the housing 21. The deceleration mechanism 41 reduces the rotational speed of the rotational power output from the output shaft 39 of the motor 36 and then transmits the rotational power to the output body 33. In the present embodiment, the speed reduction mechanism 41 includes a transmission shaft 42, a one-way clutch 43, and a plurality of (two in this case) gears 44.

The transmission shaft 42 is a shaft that supports a plurality of gears 44. The transmission shaft 42 is rotatably attached to the housing 21, and its rotation axis extends in the left-right direction and is the same as the central axis of the transmission shaft 42. The transmission shaft 42 is supported by a bearing 46c attached to the first divided body 22 and a bearing 46d attached to the second divided body 23.

The gear 44 transmits the rotational power output from the motor 36 to the output body 33. In the present embodiment, the plurality of gears 44 are the first gear 441 to which the rotational power output from the motor 36 is input, and the rotational power input to the first gear 441 is input and output via the transmission shaft 42. A second gear 448 that is transmitted to the body 33.

The first gear 441 meshes with the tooth portion 391 of the output shaft 39. The first gear 441 is rotatably attached to the housing 21 by the transmission shaft 42 via the one-way clutch 43. The rotation axis of the first gear 441 is along the left-right direction and is the same as the central axis of the transmission shaft 42. In the present embodiment, the rotation shaft of the first gear 441 is substantially parallel to the rotation shaft of the output shaft 39 and the rotation shaft of the crankshaft 28. The first gear 441 has a tooth portion 442. The tooth portion 442 is formed on the outer peripheral surface of the first gear 441. The tooth trace of the tooth portion 442 is substantially parallel to the rotation axis of the first gear 441, and the tooth portion 442 meshes with the tooth portion 391 of the output shaft 39. As a result, the first gear 441 is rotated by the rotational power of the output shaft 39. The number of teeth of the tooth portion 442 of the first gear 441 is larger than the number of teeth of the output body tooth portion 331.

The second gear 448 is aligned with the first gear 441 in the axial direction of the transmission shaft 42. In the present embodiment, the second gear 448 is arranged on the right side of the first gear 441. The second gear 448 is rotatably attached to the housing 21 by the transmission shaft 42. In the present embodiment, the second gear 448 is fixed to the transmission shaft 42 and rotates together with the transmission shaft 42. The rotation axis of the second gear 448 is the same as the rotation axis of the transmission shaft 42, that is, the same as the rotation axis of the first gear 441. The second gear 448 has a tooth portion 449. The tooth portion 449 is formed on the outer peripheral surface of the second gear 448.

In the present embodiment, the second gear 448 is attached to the transmission shaft 42, but in the present disclosure, the tooth portion 449 may be directly formed on the outer peripheral portion of the transmission shaft 42.

The tooth portion 449 of the second gear 448 meshes with the output body tooth portion 331. As a result, the rotational power of the second gear 448 is transmitted to the output body 33. The number of teeth of the tooth portion 449 of the second gear 448 is smaller than the number of teeth of the tooth portion 442 of the first gear 441.

The one-way clutch 43 is arranged between the first gear 441 and the transmission shaft 42 in the transmission path of the rotational power from the motor 36 to the output body 33. The one-way clutch 43 is, for example, a ratchet type one-way clutch. The one-way clutch 43 allows only transmission of rotational power from the first gear 441 to the transmission shaft 42 when the output body 33 rotates in one direction. The “one direction” here is the direction of rotation of the output body 33 when the electric bicycle 1 is moved forward.

Specifically, the one-way clutch 43 shifts from the first gear 441 to the transmission shaft 42 when the rotation speed of the first gear 441 is faster than the rotation speed of the transmission shaft 42 when the electric bicycle 1 moves forward. The rotational power is transmitted to it. On the other hand, the one-way clutch 43 moves from the first gear 441 to the transmission shaft 42 when the rotation speed of the first gear 441 is lower than the rotation speed of the transmission shaft 42 when the electric bicycle 1 moves forward. Do not transmit rotational power (cut off power transmission).

As a result, for example, when the motor 36 is stopped and the driver pedals the pedal 93 (see FIG. 1), rotational power is not transmitted from the crankshaft 28 to the output shaft 39 and the rotor 38. Therefore, in the present embodiment, compared with the case where the rotational power is transmitted from the transmission shaft 42 to the rotor 38, the pedaling force for pedaling 93 may be small, and the pedaling force required for rotating the wheels 65, 66 is suppressed. be able to.

When the rotational power of the first gear 441 is transmitted to the transmission shaft 42 through the one-way clutch 43, the rotational power output from the output shaft 39 is the first gear 441, the one-way clutch 43, the transmission shaft 42, and the second gear 448. Is transmitted to the output body 33. Therefore, when the driver pedals the pedal 93 (see FIG. 1) and the motor 36 is operating, the rotational power of the second member 303 rotated by the pedaling force and the rotation of the second gear 448 rotated by the motor 36. The output body 33 rotates due to the combined force with the power. As shown in FIG. 1, the rotational power of the output body 33 is transmitted to the wheels via the power transmission body 8 to move the electric bicycle 1.

Thus, in the present embodiment, the rotational power from the motor 36 is transmitted to the output body 33 in the order of the first gear 441, the one-way clutch 43, the transmission shaft 42, and the second gear 448. In short, the plurality of gears 44 transmits the rotational power output from the motor 36 to the output body 33. However, in the present disclosure, the gear 44 does not have to include both the first gear 441 and the second gear 448, and the transmission shaft 42 is not necessarily required, and one gear 44 outputs the output shaft 39 and the output shaft 39. It may be interposed between the body 33 and the body 33.

The control board 45 has a control unit that controls the motor 36. The control board 45 is a printed board in the present embodiment. The thickness direction of the control board 45 is substantially parallel to the left-right direction. The control board 45 is located on the left side of the first mating surface 226 and the second mating surface 236 of the housing 21.

The control unit mainly includes a microcontroller having one or more processors and one or more memories. That is, the function of the control unit is realized by the processor of the microcontroller executing the program recorded in the memory of the microcontroller. The program may be recorded in a memory in advance, or may be recorded in a non-transitory recording medium such as a memory card and provided. A battery 9 (see FIG. 1) is electrically connected to the control unit, and power is supplied from the battery 9. The stator 37 is electrically connected to the control unit.

The mounting surface 451 of the control board 45 is covered with a potting resin 452. As a result, the electronic component mounted on the control board 45 is covered with the potting resin 452. Examples of the potting resin 452 include urethane resin, silicon, epoxy resin, rubber and the like. In the present disclosure, potting resin 452 may be transparent, semi-transparent, or opaque.

The “mounting surface 451” in the present disclosure means a range where electronic components are mounted on the control board 45. For example, when the electronic component is surface-mounted (SMT), the mounting surface 451 is a part or all of the one surface of the control board 45. When the electronic components are mounted on both sides, the mounting surface 451 is a part or all of both sides of the control board 45. Therefore, the potting resin 452 according to the present embodiment only needs to cover the portion corresponding to the mounting surface 451 of the control board 45. In the present embodiment, the control substrate 45 is covered on both sides with potting resin 452.

Examples of electronic components include capacitors, integrated circuits, Hall ICs (Integrated Circuits), FETs (Field effect transistors), diodes, coils, resistors, connectors, and the like. The FET is a switching element for supplying electric power to the motor 36, and includes a junction type FET, MOSFET and MESFET.

As shown in FIG. 2, the motor unit body 20 according to the present embodiment includes a crankshaft rotation detection device 47 and a motor rotation detection device 50.

The crankshaft rotation detection device 47 detects the rotation state of the crankshaft 28. As shown in FIG. 3, the crankshaft rotation detection device 47 includes a rotation dog 48 (detected portion) and a crankshaft rotation sensor 49 in the present embodiment. In the present embodiment, the rotation state of the crankshaft 28 is detected by outputting the electric signal detected by the crankshaft rotation sensor 49 to the control unit and executing the processing by the control unit.

The rotating dog 48 is attached to the second member 303 and is fixed to the rotating body 29. Therefore, the rotary dog 48 rotates together with the crankshaft 28. The rotary shaft of the rotary dog 48 is the same as the rotary shaft of the crankshaft 28. In the present embodiment, the rotary dog 48 includes a tubular body portion 481 that is fitted into the outer periphery of the second member 303, and a protruding portion 482 that projects from the tubular body portion 481 in the radial direction. The protruding portion 482 is formed in an annular shape. The protruding portion 482 has a light transmitting portion (not shown) formed at a constant pitch in the circumferential direction. The light transmitting portion is a portion that transmits light, and is, for example, a notch, a hole, a window, or the like.

The crankshaft rotation sensor 49 is an optical sensor in the present embodiment. The crankshaft rotation sensor 49 is attached to the first divided body 22 of the housing 21. The crankshaft rotation sensor 49 includes a light emitting element (for example, an LED) and a light receiving element (for example, a phototransistor). The light emitting element and the light receiving element are connected to the control unit so as to be able to exchange electric signals. In this embodiment, the light emitting element and the light receiving element are arranged in the left-right direction. A rotary dog 48 is located between the light emitting element and the light receiving element. The crankshaft rotation sensor 49 emits light from the light emitting element toward the light receiving element, and receives the light passing through the light transmitting portion by the light receiving element.

However, in the present disclosure, the crankshaft rotation detection device 47 is not limited to the above configuration. For example, an annular ferrite magnet may be used in the portion corresponding to the protrusion 482 as the rotating dog 48, and an electromagnetic rotation sensor that detects a change in the magnetic field may be used as the crankshaft rotation sensor 49. Further, the crankshaft rotation detection device 47 may be provided with a dedicated controller for the crankshaft rotation sensor 49.

The motor rotation detection device 50 detects the rotation state of the output shaft 39 of the motor 36. As shown in FIG. 2, the motor rotation detection device 50 includes a rotation member 51 and a motor rotation sensor 52 in the present embodiment.

The rotating member 51 is attached to the outer peripheral surface of the output shaft 39 of the motor 36 and rotates together with the output shaft 39. Therefore, the rotating shaft of the rotating member 51 is the same as the rotating shaft of the output shaft 39. The rotating member 51 is arranged between the rotor 38 and the first gear 441. The rotating member 51 is located on the left side of the control board 45. The rotating member 51 is, for example, a member in which magnets are embedded so that magnetic poles are alternately switched in the circumferential direction of the rotating member 51, or a magnet magnetized so that magnetic poles are alternately switched in the circumferential direction.

The motor rotation sensor 52 is a Hall IC that detects the magnetic force of the magnet of the rotating member 51. The motor rotation sensor 52 is mounted on the surface of the control board 45 that faces the rotating member 51 (here, the left surface). The motor rotation sensor 52 detects the rotation state of the rotating member 51 by outputting an electric signal indicating a change in the magnetic field accompanying the rotation of the rotating body 29 to the control unit and executing processing by the control unit.

The housing 21 has an oil receiving portion 24, as shown in FIG. The oil receiving portion 24 is a portion that receives the oil 54 when the oil 54 described later is scattered. In the present embodiment, the oil receiving portion 24 is provided at a position corresponding to the first gear 441. Although the oil receiving portion 24 is a part of the housing 21 in the present embodiment, a plate-shaped member made of synthetic resin or the like may be attached to the housing 21.

The “position corresponding to the first gear 441” in the present disclosure means a position that overlaps the first gear 441 on the vertical plane including the front-rear direction. In the present embodiment, the oil receiving portion 24 and the first gear 441 at least partially overlap each other when viewed in the vertical direction, and more preferably, the entire first gear 441 overlaps the oil receiving portion 24.

The lower end 241 of the oil receiving portion 24 (the lowest position of the oil receiving portion 24) faces the output shaft 39 of the motor 36. In the present embodiment, the oil receiving portion 24 is curved so as to be convex in the upward direction, and in the longitudinal direction of the oil receiving portion 24, as it goes to the output shaft 39 side, the oil receiving portion 24 moves downward with respect to the horizontal plane. Is tilted. In the present embodiment, the output shaft 39 is located on the extension line of the lower surface of the oil receiving portion 24. Therefore, the oil 54 received by the lower surface of the oil receiving portion 24 flows along the oil receiving portion 24 to the output shaft 39.

(1.2.2.2) Oil The motor unit 2 according to the present embodiment includes oil 54, as shown in FIG. The oil 54 at least lubricates the gear 44 with oil. In this embodiment, the motor 36 and the gear 44 can be cooled in addition to the oil lubrication of the gear 44. Therefore, the oil 54 according to the present embodiment is mechanical oil that can cool the friction heat generated in the gear 44 and the heat generation of the motor 36.

The oil 54 is a liquid in this embodiment. Oil 54, unlike high clay grease, is fluid. However, in the present disclosure, among the greases, a grease having a high fluidity range (for example, a consistency of 400 or more) is included in “oil 54” in the present disclosure.

Examples of the oil 54 include mission oil, gear oil, industrial hydraulic oil, turbine oil, compressor oil, cutting oil, engine oil, and the like.

As shown in FIG. 4, the oil 54 is stored in the housing 21 in a certain amount or more. The “constant amount” in the present disclosure means that at least a part of the gear 44 or the gear 33 is submerged in the oil 54 when the motor unit 2 is in a state where the rotation axis of the output body 33 is along the horizontal plane. To do. The “state in which the rotation axis of the output body 33 is along the horizontal plane” does not mean all aspects in which the rotation axis of the output body 33 is along the horizontal plane, but means at least one state. In the present embodiment, the “state in which the rotation axis of the output body 33 is along the horizontal plane” is, for example, the state in which the crankshaft 28 is along the horizontal plane, and the state in which the motor unit 2 is attached to the bracket 78. That is.

In the present embodiment, part of the tooth portion 442 of the first gear 441 and part of the side surface 443 are submerged in the oil 54 when the rotation axis of the output body 33 is along the horizontal plane in the motor unit 2. In short, at least a part of the gear 44 is immersed in the oil 54 with the rotation axis of the output body 33 along the horizontal plane. At this time, part of the output body tooth portion 331 is also immersed in the oil 54.

In the motor unit 2 according to this embodiment, when the motor 36 operates, the output shaft 39 rotates, and the first gear 441 rotates as the output shaft 39 rotates. At this time, in the present embodiment, since the first gear 441 is immersed in the oil 54, the oil 54 is scooped up as the first gear 441 rotates. As a result, the oil 54 reaches the portion where the first gear 441 and the output shaft 39 are meshed with each other, and oil lubricates the first gear 441 and the output shaft 39.

In the present embodiment, part of the output body tooth portion 331 is also immersed in the oil 54. Therefore, oil lubrication can be effectively performed also in the meshing portion between the output body tooth portion 331 and the second gear 448.

In addition, the output body tooth portion 331 scrapes up the oil 54 as it rotates. The scraped oil 54 is received by the lower surface of the oil receiving portion 24. The oil 54 received on the lower surface of the oil receiving portion 24 flows on the output shaft 39 along the oil receiving portion 24 as described above. Therefore, according to the motor unit 2 of the present embodiment, during the operation of the motor 36, the oil 54 can be constantly supplied to the meshing portion between the first gear 441 and the output shaft 39, and the oil film is unlikely to run out.

As described above, in the present embodiment, the tooth portion 442 of the first gear 441 and the tooth portion 331 of the output body are immersed in the oil 54 with the rotation axis of the output body 33 along the horizontal plane, and the motor 36 operates. The oil 54 is scattered. However, in this embodiment, the mounting surface 451 of the control board 45 is covered with the potting resin 452. Therefore, the scattered oil 54 is prevented from adhering to the electronic component.

The oil 54 may be stored in advance when the motor unit 2 is manufactured, but as shown in FIG. 4, an oil inlet 55 may be formed in the housing 21.

The oil injection port 55 is a through hole that allows the outside and the inside of the housing 21 to pass therethrough. The oil injection port 55 is preferably formed, for example, above the designed position of the liquid surface of the oil 54 with respect to the housing 21 with the rotation axis of the output body 33 along the horizontal plane. A cap is attached to the oil inlet 55.

(2) Modifications The above embodiment is only one of the various embodiments of the present disclosure. The embodiment can be variously modified according to the design and the like as long as the object of the present disclosure can be achieved. The modifications described below can be applied in appropriate combination.

(2.1) Modification 1
In the motor unit 2 according to the modified example 1, as shown in FIG. 5, when the tooth trace of the tooth portion 442 a of the first gear 441 a of the gear 44 meshes with the output shaft 39, the rotation shaft of the output shaft 39 Leaning against. Specifically, the first gear 441a according to this modification is a helical gear. However, in the present disclosure, the first gear 441a may be, for example, a helical gear, a screw gear, a worm gear, or the like. As for the tooth trace of the first gear 441a, the side farther from the rotor 38 in the axial direction of the output shaft 39 in the rotation direction of the first gear 441a when the electric bicycle 1 moves in the forward direction is the rotor in the axial direction of the output shaft 39. It is located before the side close to 38.

The first gear 441a according to this modification is arranged in the left-right direction with respect to the motor 36, as in the above embodiment. More specifically, the first gear 441a at least partially overlaps the motor 36 when viewed in the axial direction of the output shaft 39 of the motor 36.

In this modification, the first gear 441a is rotated by the output of the output shaft 39 of the motor 36, and when the first gear 441a scrapes up the oil 54 (see FIG. 4), the oil 54 moves along the tooth lines. It moves and scatters toward the stator 37. The scattering of the oil 54 is realized by, for example, centrifugal force applied to the first gear 441a and contact between teeth during meshing. Therefore, in the present modification, the oil 54 can provide oil lubrication between the tooth portion 442a of the first gear 441a and the tooth portion 391 of the output shaft 39, and at the same time, the motor 36 can be cooled.

In the present modification, the first gear 441a is a helical gear, but in the present disclosure, the second gear 448 of the gear 44 may be a helical gear. Further, in the biaxial motor unit 2 described in “Modification 4” described later, the gear 44a may be a helical gear or the like.

(2.2) Modification 2
As shown in FIG. 6B, the motor unit 2 according to Modification 2 differs from the above-described embodiment in that a plurality of recesses 444 are provided on the side surface 443 of the first gear 441b (gear 44b). The “side surface 443” here is a surface of the first gear 441b that is orthogonal to the outer peripheral surface on which the tooth portion 442 is formed. The first gear 441b includes a pair of side surfaces 443. The transmission shaft 42 penetrates the pair of side surfaces 443.

The first gear 441b includes a plurality of recesses 444 on a surface of the pair of side surfaces 443 facing the motor 36. The recess 444 is a portion recessed from the side surface 443 of the first gear 441b. The at least one recess 444 is immersed in the oil 54 with the rotation axis of the output body 33 being along the horizontal plane. The plurality of recesses 444 are formed on the side surface 443 of the first gear 441b so as to be lined up around the rotation axis of the first gear 441b. In this modified example, each recess 444 includes a bottom surface 445 and a plurality (here, four) of inner side surfaces 446, as shown in FIG. 6B.

By the way, FIG. 6B is a cross-sectional view taken along the line AA of FIG. 6A. FIG. 6B is a cross-sectional view in a cross section orthogonal to the radial direction of the rotation axis and overlapping the recess 444. As shown in FIG. 6B, in the first gear 441b according to the present modification, the surface 447 of the plurality of inner side surfaces 446 that intersects the rotation direction of the gear 44 is not inclined with respect to the side surface 443. .. More specifically, the surface 447 approaches the opposing inner side surface 446 as it goes from the side surface 443 to the bottom surface 445 side.

Therefore, the oil 54 collected in the recess 444 easily moves along the surface 447 as the first gear 441b rotates, and the moved oil 54 easily scatters toward the motor 36.

In addition, a corner portion formed by the surface 447 of the plurality of inner side surfaces 446 that intersects the rotation direction of the gear 44 and the bottom surface 445 has an arc shape. Therefore, the oil 54 attached to the bottom surface 445 of the recess 444 also smoothly moves to the surface 447 and is easily scattered toward the motor 36.

For example, the plurality of recesses 444 may be formed by partitioning the longitudinal direction of the groove on the side surface 443 of the gear 44 in a ring shape around the rotation axis by a plurality of partition plates.

(2.3) Modification 3
In the motor unit 2 according to the modified example 3, as shown in FIG. 7A, the control board 45 is not covered with the potting resin 452 (see FIG. 2), but the oil 54 (see FIG. 4) is provided in the housing 21a. ) Is stored in a different space from the space where it is stored. As a result, the electronic components of the control board 45 are protected from the oil 54 splashing. In the present modified example, the housing 21a includes a first space 25 as a space in which the oil 54 is stored, and a second space 26 partitioned from the first space 25. A partition 27 is formed between the first space 25 and the second space 26.

The second space 26 is adjacent to the motor 36 in this modification. A part of the partition 27 is the motor cup 40. The partition 27 is formed with a hole 272a through which a wire 453 or a terminal for supplying electric power to the stator 37 is inserted, and a hole 272b for the motor rotation sensor 52. A seal member 273 made of rubber or the like is arranged between the wire 453 and the hole 272a and between the motor rotation sensor 52 and the hole 272b. By providing the seal member 273, it is possible to suppress the oil 54 from scattering from the first space 25 to the second space 26 through the holes 272a and 272b.

In this modification, the first space 25 and the second space 26 communicate with each other only through holes for the motor 36 and the motor rotation sensor. Therefore, the oil 54 scattered in the first space 25 is unlikely to move to the second space 26. Therefore, the control board 45 according to the present modification can suppress the oil 54 from splashing.

However, in the present modification, the first space 25 and the second space 26 are not substantially in communication with each other, but if the partition 27 can prevent the oil 54 from splashing with respect to the control board 45, the first space 25 can be formed. And the second space 26 may communicate with each other. In short, two spaces divided by a partition into one space may be the first space 25 and the second space 26.

In the present modification, the rotating member 51 attached to the outer peripheral surface of the output shaft 39 of the motor 36 is arranged in the first space 25, but in the present disclosure, the rotating member 51 is as shown in FIG. 7B. In addition, it is preferable that the second space 26 is arranged.

In this case, the output shaft 39 penetrates the partition 27 between the first space 25 and the second space 26 (the hole through which the output shaft 39 passes is referred to as a through hole 270). That is, the output shaft 39 has a portion 390 protruding from the partition 27 and extending to the inside of the second space 26. The rotating member 51 is attached to the portion 390 of the output shaft 39 located in the second space 26.

The motor rotation sensor 52 is mounted on the control board 45 arranged in the second space 26. The rotating member 51 rotates near the control board 45. The motor rotation sensor 52 reads the rotation state of the rotating member 51 and outputs its electric signal to the control unit. The control unit detects the rotation speed of the output shaft 39 by executing the processing of the electric signal. In short, the motor rotation sensor 52 can detect the rotation speed of the output shaft 39 of the motor 36. The partition 27 has a hole 272 through which a wiring 453 or a terminal for supplying electric power from the control board 45 to the stator 37 is inserted. A seal member 273 made of rubber or the like is arranged between the wiring 453 and the hole 272. By providing the seal member 273, it is possible to suppress the oil 54 from scattering from the first space 25 to the second space 26 through the hole 272.

The bearing 46e is arranged on the side of the first space 25 with respect to the partition 27 between the first space 25 and the second space 26.

A seal member 271 is arranged in the through hole 270. The seal member 271 seals between the outer peripheral surface of the output shaft 39 and the inner peripheral surface of the through hole 270. The seal member 271 is arranged between the bearing 46e and the rotating member 51. Here, the seal member 271 is preferably an oil seal, but may be, for example, an O-ring, a lip packing, a gland packing, a mechanical seal, or the like. By providing the seal member 271, it is possible to suppress the oil 54 from scattering through the through hole 270 from the first space 25 to the second space 26.

(2.4) Modification 4
In the above-described embodiment, the motor unit 2 is a uniaxial type, but this modification is different in that the motor unit 2a is a biaxial type.

The motor unit main body 20a of the present modification example includes a housing 21, a crankshaft 28, a rotating body 29, a driving body 34, a one-way clutch 31, a driving sprocket 35, a control board 45, a motor 36, a reduction mechanism 41a, and an output body 33a. .. The case 21, the crankshaft 28, the rotating body 29, the one-way clutch 31, the drive sprocket 35, the control board 45, and the motor 36 are the same as those in the above embodiment.

The driving body 34 receives the external force (pedaling force) input to the crankshaft 28 and outputs it to the driving sprocket 35. The driving body 34 is different from the output body 33 in the above-described embodiment in that it does not have the output body tooth portion 331, but is the same in other respects. A drive sprocket 35 is attached to the drive body 34.

The deceleration mechanism 41a reduces the rotational speed of the output shaft 39 of the motor 36 and then transmits the rotational power of the output shaft 39 to the output body 33a. The reduction mechanism 41a according to this embodiment includes a gear 44a and a one-way clutch 43. The gear 44 a is rotatably attached to the housing 21. The rotation axis of the gear 44a is the same as the central axis of the output body 33a, and extends along the left-right direction. The rotation axis of the gear 44a is substantially parallel to the rotation axis of the crankshaft 28 in this embodiment.

A tooth portion 442 is formed on the outer peripheral surface of the gear 44a. The tooth portion 442 meshes with the tooth portion 391 of the output shaft 39 of the motor 36. As a result, the rotational power of the output shaft 39 is transmitted to the gear 44a, and the gear 44a rotates together with the output shaft 39. The number of teeth of the tooth portion 442 is larger than the number of teeth of the tooth portion 391 of the output shaft 39.

The output body 33a is supported by a bearing 46g attached to the first divided body 22 and a bearing 46h attached to the second divided body 23. Thereby, the output body 33a is rotatably attached to the housing 21. The rotation axis of the output body 33a extends in the left-right direction and is substantially parallel to the rotation axis of the output shaft 39. A one-way clutch 43 is arranged between the output body 33a and the gear 44a.

The one-way clutch 43 is a ratchet type one-way clutch in the present modification. The one-way clutch 43 transmits rotational power from the gear 44a to the output body 33a when the rotation speed of the gear 44a is faster than the rotation speed of the output body 33a while the output body 33a is rotating in one direction. .. On the other hand, the one-way clutch 43 transmits rotational power from the gear 44a to the output body 33a when the rotation speed of the gear 44a is lower than the rotation speed of the output body 33a. Here, "when rotating in one direction" means when the output body 33a is rotating in the direction in which the electric bicycle 1 is moved forward.

That is, the one-way clutch 43 allows only the transmission of the rotational power from the gear 44a to the output body 33a and moves the rotational power from the output body 33a to the gear 44a when moving in the front direction of the electric bicycle 1. Do not allow. Therefore, for example, when the motor 36 is stopped and the driver pedals the pedal 93 (see FIG. 1), the output shaft 39 and the rotor 38 are prevented from rotating.

The right end of the output body 33a penetrates the second side wall 231 of the second split body 23. A second drive sprocket 35a is fixed to an end portion on the right side of the output body 33a that protrudes to the outside of the housing 21.

When the rotational force of the gear 44a is transmitted to the output body 33a through the one-way clutch 43, the rotational power of the output shaft 39 is transmitted to the gear 44a, the one-way clutch 43 and the output body 33a in order, and then to the second drive sprocket 35a. introduce. In the present modification, the drive assist output is output from the output body 33a.

In this modification, as shown in FIG. 9A, at least a part of the gear 44a is immersed in the oil 54 with the rotation axis of the output body 33a being along the horizontal plane. In this modification, in this state, only the gear 44a is immersed in the oil 54, but the rotation of the gear 44a can lubricate the gear 44a and the output shaft 39 with oil.

In this modified example, the oil 54 is stored without providing a partition or the like inside the housing 21, but as shown in FIG. 9B, at least the oil sump portion 211 surrounding the output shaft 39 and the reduction mechanism 41a. May be provided. The oil sump portion 211 is formed by partitioning the inside of the housing 21 with a partition portion 213 into a space (the oil sump portion 211) where the output shaft 39 and the speed reduction mechanism 41a are located and the other space 212. The partition part 213 is included in the housing 21. The oil inlet 55 communicates with the oil sump 211.

By storing the oil 54 only in the oil sump 211 in the housing 21 so that at least a part of the gear 44a is immersed in the oil 54 with the rotation axis of the output body 33a along the horizontal plane, The amount of oil 54 allows constant oil lubrication.

(2.5) Other Modified Examples Hereinafter, modified examples of the embodiment will be listed.

In the motor unit 2 according to the above-described embodiment, the gear 44 is partially immersed in the oil 54 in a state where the rotation axis of the output body 33 is along the horizontal plane, but in the present disclosure, the entire gear 44 is the oil 54. You may soak in.

In the above embodiment, a part of the first gear 441 and a part of the output body tooth portion 331 of the output body 33 are submerged in the oil 54, but in the present disclosure, the first gear 441 is not submerged in the oil 54. Only the output body tooth portion 331 may be immersed in the oil 54.

Although the rotation member 51 and the motor rotation sensor 52 are provided as the motor rotation detection device 50 in the above embodiment, in the present disclosure, the rotation of the output shaft 39 of the motor 36 is used as the motor rotation detection device 50. An angle sensor that detects an angle may be adopted. As the angle sensor, for example, a resolver such as a VR resolver or a brushless resolver is preferably used. Resolvers are resistant to flooding. Therefore, if a resolver is used as the motor rotation detection device 50, it is not always necessary to cover the control substrate 45 with resin potting or arrange the control substrate 45 in a space different from the oil 54. Is effective.

In the above embodiment, the housing 21 does not have a drain for draining the oil 54, but the housing 21 may have a drain. Further, the drain cap for closing the drain may be provided with a magnet to be inserted into the drain port. According to this, during the initial operation of the motor unit 2, so-called fine metal powder that is scraped off by familiar wear can be magnetically adhered by the magnet, and the occurrence of rust inside the motor unit body 20 can be suppressed. You can

In the above embodiment, when the oil 54 was injected into the motor unit main body 20, it was not possible to grasp the proper amount of the oil 54. However, for example, as shown in FIG. A visual recognition portion 53 indicating the amount of 54 may be provided. The visual recognition unit 53 is, for example, a transparent pipe that communicates with the inside of the housing 21. The term "transparent" as used herein only needs to allow the internal oil 54 to be visually recognized, and includes transparent or translucent. The visual recognition unit 53 includes a lower pipe 531 connected to the housing 21, a standing pipe 532 connected to the lower pipe 531, and an upper pipe 533 connected to the standing pipe 532 and the housing 21. The lower pipe 531, the standing pipe 532, and the upper pipe 533 communicate with the inside of the housing 21.

According to this, when the oil 54 is stored inside the housing 21, the liquid level of the oil 54 appears in the standing pipe 532, so that the liquid level of the oil 54 can be confirmed. In short, the visual recognition part 53 can indicate the amount of the oil 54. Note that, as the visible portion 53, opaque pipes may be used as the upper pipe 533 and the lower pipe 531 and only a part of the standing pipe 532 may be formed as a transparent portion. Further, as the visual recognition part 53, a transparent window may be formed in a part of the housing 21 so that the liquid level of the oil 54 can be visually recognized. A level gauge may be adopted as the visual recognition unit 53. After inserting the level gauge into the housing 21, the level gauge may be pulled out and the amount of the oil 54 may be confirmed by looking at the oil 54 attached to the level gauge.

The motor unit 2 according to the above-described embodiment is the uniaxial motor unit 2 and the modified example 4 is the biaxial motor unit 2a. However, the motor unit according to the present disclosure may be a hub motor. .. The hub motor includes a rear hub motor attached to the hub of the rear wheels and a front hub motor attached to the hub of the front wheels.

The output body of the hub motor is a case that rotates with respect to the mounting shaft. The case doubles as the case. With the rotation axis of the case along the horizontal plane, at least a part of gears (for example, planetary gears) in the case is immersed in the oil stored in the case.

In the present disclosure, expressions with “substantially” such as “substantially parallel” or “substantially orthogonal” may be used. For example, “substantially parallel” means substantially “parallel”, and includes not only a strictly “parallel” state but also an error of about several percent. The same applies to other expressions with "abbreviation".

Further, in the present disclosure, expressions such as “front end” and “front end” that are distinguished by “...end” and “...end” are used. For example, the “front end” means a portion having a certain range including the “front end”. The same applies to other expressions involving "... edge".

(3) Mode As described above, the motor unit (2, 2a) according to the first mode is capable of traveling by adding the driving assist output generated by the motor (36) to the human-powered driving force ( Used in 1). The motor unit (2, 2a) includes a housing (21, 21a), a motor (36), an output body (33, 33a), gears (44, 44a, 44b), and oil (54). Prepare The motor (36) is attached to the housing (21, 21a). The output body (33, 33a) outputs the drive assist output from the motor (36). The gears (44, 44a, 44b) transmit the drive assist output output from the motor (36) to the output body (33, 33a), and are housed in the housing (21, 21a). The oil (54) is stored in the housings (21, 21a) and lubricates the gears (44, 44a, 44b) with oil. In the motor unit (2, 2a), at least a part of the gears (44, 44a, 44b) is submerged in the oil (54) with the rotation shaft of the output body (33, 33a) along the horizontal plane.

According to this aspect, since the oil (54) can be continuously supplied to the gears (44, 44a, 44b), the gears (44, 44a, 44b) can be oil-lubricated, and the lubricating performance can be improved. Can be improved. As a result, according to this aspect, downsizing of the motor unit (2, 2a) can be realized.

The motor unit (2, 2a) according to the second aspect further includes the crankshaft (28) that receives human power and rotates in the first aspect.

According to this aspect, the motor unit (2, 2a) having the crankshaft (28) can be downsized.

The motor unit (2, 2a) according to the third aspect further includes a torque sensor (32) for detecting the torque due to the human power input to the crankshaft (28) in the second aspect.

According to this aspect, the motor unit (2, 2a) having the torque sensor (32) can be downsized.

In the motor unit (2, 2a) according to the fourth aspect, in any one of the first to third aspects, the casing (21, 21a) has oil (54) inside the casing (21, 21a). Has an oil inlet (55) for injecting into.

According to this aspect, even if the amount of the oil (54) in the housing (21, 21a) decreases, the oil (54) can be added from the oil injection port (55).

In the motor unit (2, 2a) according to the fifth aspect, in any one of the first to fourth aspects, the housing (21, 21a) is a gas that is present in the housing (21, 21a). It has a pressure adjusting part (210) for reducing a pressure increase or a pressure decrease.

According to this aspect, it is possible to prevent the inside of the housing (21, 21a) from becoming high pressure or negative pressure.

In the motor unit (2, 2a) according to the sixth aspect, in any one of the first to fifth aspects, a control board (45) having a control unit that controls the motor (36) is further provided. The housing (21) is partitioned from the first space (25) in which the oil (54) is stored and the first space (25), and the second space (26) in which the control board (45) is arranged. ), and have.

According to this aspect, the electronic component mounted on the control board (45) can be protected from the oil (54).

The motor unit (2, 2a) according to the seventh aspect is the motor unit (2, 2a) according to any one of the first to fifth aspects, further including a control board (45) that controls the motor (36). The mounting surface (451) of the control board (45) is covered with a potting resin (452).

According to this aspect, the electronic component mounted on the control board (45) can be protected from the oil (54).

In the motor unit (2, 2a) according to the eighth aspect, in any one of the first to seventh aspects, the casing (21, 21a) is an oil accumulated in the casing (21, 21a). It has a visual recognition part (53) showing the amount of (54).

According to this aspect, the amount of the oil (54) can be visually confirmed when the oil (54) is supplied from the oil inlet (55).

In the motor unit (2, 2a) according to the ninth aspect, in any one of the first to eighth aspects, the gear (44a) meshes with the output shaft (39) of the motor (36). .. The teeth of the gear (44a) are inclined with respect to the rotation axis of the output shaft (39) when meshed with the output shaft (39).

According to this aspect, when the gear (44a) and the output shaft (39) of the motor (36) mesh with each other, the oil (54) flies toward the motor (36), so that the oil (54) causes the motor (36) to move. Can be cooled.

In the motor unit (2, 2a) according to the tenth aspect, in any one of the first to ninth aspects, the gear (44b) rotates the gear (44b) on the side surface (443) of the gear (44b). It has a plurality of recesses (444) formed so as to be lined up around the axis.

According to this aspect, when the gear (44b) rotates with the oil (54) in the recess (444), the oil (54) in the recess (444) tends to fly. As a result, the oil (54) can be supplied to the peripheral parts of the gear (44b), and cooling and oil lubrication effects can be exerted.

In the motor unit (2, 2a) according to the eleventh aspect, in the tenth aspect, in the recess (444), a surface intersecting with the rotation direction of the gear (44b) is inclined with respect to the side surface (443). ing.

According to this aspect, the oil (54) that has entered the recess (444) is likely to fly due to the centrifugal force generated by the rotation of the gear (44b).

The motor unit main body (20, 20a) according to the twelfth aspect is used for an electric bicycle (1) that can travel by adding a drive assist output generated by a motor (36) to a human-powered driving force. The motor unit body (20, 20a) includes a housing (21, 21a), a motor (36), an output body (33, 33a), and gears (44, 44a, 44b). The motor (36) is attached to the housing (21, 21a). The output body (33, 33a) outputs the drive assist output from the motor (36). The gears (44, 44a, 44b) transmit the drive assist output output from the motor (36) to the output body (33, 33a), and are housed in the housing (21). The casings (21, 21a) have an oil injection port (55) for injecting oil (54) for lubricating the gears (44, 44a, 44b) into the casings (21, 21a).

According to this aspect, the oil (54) is put into the motor unit main body (20, 20a) from the oil inlet (55) and the oil (54) is stored in the housing (21, 21a). Thus, the oil (54) can be continuously supplied to the gears (44, 44a, 44b). Therefore, the gears (44, 44a, 44b) can be lubricated with oil, and the lubrication performance can be improved. As a result, according to this aspect, downsizing of the motor unit (2, 2a) can be realized.

An electric bicycle (1) according to a thirteenth aspect includes a frame (7), a motor unit (2, 2a) according to any one of the first to eleventh aspects attached to the frame (7), and a plurality of wheels. (65) and (66), and a power transmission body (8). A plurality of wheels (65) (66) are mounted on the frame (7). The power transmission body (8) transmits the power output from the motor unit (2, 2a) to at least one of the plurality of wheels (65) (66).

According to this aspect, in the electric bicycle (1), it is possible to continue supplying the oil (54) to the gears (44, 44a, 44b) during traveling, so that the oil is not applied to the gears (44, 44a, 44b). Lubrication can be performed and lubrication performance can be improved.

An electric bicycle (1) according to a fourteenth aspect includes a frame (7), a motor unit main body (20, 20a) according to the twelfth aspect attached to the frame (7), and a plurality of wheels (65) (66). ) And a power transmission body (8). A plurality of wheels (65) (66) are mounted on the frame (7). The power transmission body (8) transmits the power output from the motor unit main body (20, 20a) to at least one of the plurality of wheels (65) (66).

According to this aspect, the oil (54) is put into the motor unit main body (20, 20a) from the oil inlet (55) and the oil (54) is stored in the housing (21, 21a). Thus, the oil (54) can be continuously supplied to the gear (44). Therefore, in the electric bicycle (1), it is possible to continue supplying the oil (54) to the gears (44, 44a, 44b) during traveling, so that the gears (44, 44a, 44b) should be lubricated with oil. It is possible to improve the lubrication performance.

The configurations according to the second to eleventh aspects are not essential for the motor unit (2, 2a) and can be omitted as appropriate.

1 Electric Bicycle 2, 2a Motor Unit 20, 20a Motor Unit Main Body 21, 21a Housing 25 First Space 26 Second Space 28 Crank Shaft 33, 33a Output Body 36 Motor 39 Output Shaft 44, 44a, 44b Gear 443 Side Side 444 Recess 446 Inner surface 447 Surface 45 Control board 451 Mounting surface 452 Potting resin 53 Visual part 54 Oil 55 Oil injection port 65, 66 Wheel 7 Frame 8 Power transmission body

Claims (14)

A motor unit used for an electric bicycle, which is capable of traveling by adding a driving assist output generated by a motor to a human-powered driving force,
Housing and
A motor attached to the housing,
An output body that outputs the drive auxiliary output from the motor,
The drive auxiliary output output from the motor is transmitted to the output body, and a gear accommodated in the housing,
Oil stored in the housing and lubricating the gear with oil,
Equipped with
With the rotation axis of the output body along a horizontal plane, at least a part of the gear is immersed in the oil,
Motor unit. Further comprising a crankshaft that penetrates the housing and rotates by receiving human power,
The motor unit according to claim 1. Further comprising a torque sensor that detects torque due to human power input to the crankshaft,
The motor unit according to claim 2. The housing has an oil inlet for injecting the oil into the housing,
The motor unit according to claim 1. The case has a pressure adjusting unit for reducing a pressure increase or a pressure decrease of the gas existing in the case,
The motor unit according to claim 1. Further comprising a control board having a control unit for controlling the motor,
The housing is
The first space where the oil is stored,
A second space that is partitioned from the first space and in which the control board is arranged,
Has,
The motor unit according to claim 1. Further comprising a control board for controlling the motor,
The mounting surface of the control board is covered with potting resin,
The motor unit according to claim 1. The casing has a visual recognition portion that indicates the amount of the oil accumulated in the casing,
The motor unit according to any one of claims 1 to 7. The gear is meshed with the output shaft of the motor,
The tooth trace of the gear is inclined with respect to the rotation axis of the output shaft when meshed with the output shaft,
The motor unit according to claim 1. The gear has a plurality of recesses formed on the side surface of the gear so as to be arranged around the rotation axis of the gear.
The motor unit according to claim 1. In the recess, a surface intersecting the rotation direction of the gear is inclined with respect to the side surface,
The motor unit according to claim 10. A motor unit main body used for an electric bicycle that is capable of traveling by adding a drive assist output generated by a motor to a human-powered drive,
Housing and
A motor attached to the housing,
An output body that outputs the drive auxiliary output from the motor,
The drive auxiliary output output from the motor is transmitted to the output body, and a gear accommodated in the housing,
Equipped with
The case has an oil injection port for injecting oil that performs oil lubrication on the gear into the case,
Motor unit body. Frame and
The motor unit according to any one of claims 1 to 11, which is attached to the frame,
A plurality of wheels attached to the frame,
For at least one of the plurality of wheels, a power transmission body that transmits the power output from the motor unit,
With
Electric bicycle. Frame and
The motor unit main body according to claim 12, which is attached to the frame,
A plurality of wheels attached to the frame,
A power transmission body that transmits the power output from the motor unit body to at least one of the plurality of wheels,
With
Electric bicycle.

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