CN111846102A - Mid-motor and electric power-assisted bicycle - Google Patents

Abstract

The invention discloses a middle-mounted motor and an electric power-assisted bicycle, and relates to the field of electric bicycles. The middle motor comprises a shell, a stator, a rotor component, a sun gear, a planetary gear component, a first clutch component, a second clutch component and a middle shaft, wherein the stator is fixedly connected with the shell; the rotor is coaxial and is rotationally arranged in the stator; the sun gear is fixedly arranged on the rotor in a penetrating way and is rotationally connected with the shell; the planetary gear assembly comprises an inner gear ring, duplex planet teeth meshed with the inner gear ring and a planet carrier connected with the duplex planet teeth, the inner gear ring is fixedly connected with the shell, the duplex planet teeth are meshed with the sun teeth, and the planet carrier is rotationally connected with the sun teeth and fixedly connected with the duplex planet teeth; the first clutch component is fixedly connected with the planet carrier; the second clutch component is in transmission connection with the first clutch component; the middle shaft extends along the axial direction of the sun gear and is connected with the second clutch component. Through adopting planetary gear assembly, make this put light in weight of motor small, and can improve the motor moment of torsion when reducing motor rotational speed.

Description

Mid-motor and electric power-assisted bicycle

Technical Field

The invention relates to the field of electric bicycles, in particular to a middle-mounted motor and an electric power-assisted bicycle.

Background

The power-assisted bicycle is used as an auxiliary vehicle, is provided with a motor and a power auxiliary system, and can realize integration of manual riding and motor power assistance. At present, a power-assisted bicycle becomes an important vehicle for people to go out, and a motor of the power-assisted bicycle is particularly important as a main power source in a power-assisted device. A parallel tooth is adopted in a first-stage reduction gear of a traditional motor used for a power-assisted bicycle in the prior art, and nylon teeth are used, so that the working condition efficiency is low, a motor efficient platform is not wide, the tooth space torque is large, the torque is small, the temperature is increased, the reliability is poor, and the strength of the nylon teeth is low.

Disclosure of Invention

The invention aims to provide a middle-mounted motor and an electric power-assisted bicycle, wherein the middle-mounted motor is light in weight and small in size, and can improve the torque of the motor while reducing the rotating speed of the motor.

In order to achieve the purpose, the invention adopts the following technical scheme:

a mid-motor, comprising:

a housing;

the stator is fixedly connected with the shell;

the rotor assembly is coaxially and rotatably arranged inside the stator;

the sun gear is fixedly arranged in the rotor assembly in a penetrating mode and is in rotating connection with the machine shell;

the planetary gear assembly comprises an inner gear ring, duplex planet teeth meshed with the inner gear ring and a planet carrier connected with the duplex planet teeth, the inner gear ring is fixedly connected with the shell, the duplex planet teeth are meshed with the sun teeth, and the planet carrier is rotationally connected with the sun teeth and fixedly connected with the duplex planet teeth;

the first clutch component is fixedly connected with the planet carrier;

a second clutch assembly in driving connection with the first clutch assembly;

a bottom bracket extending axially along the sun gear and connected to the second clutch assembly.

Optionally, the planetary gear assembly further includes a connecting pin and a supporting frame, the connecting pin rotates to penetrate through the dual planetary gear and two ends of the dual planetary gear are respectively fixedly connected with the planet carrier and the supporting frame, and the supporting frame is fixedly connected with the first clutch assembly.

Optionally, the mid-motor further comprises a first box, the housing and the ring gear are fixed to two sides of the first box respectively, and the planet carrier and the middle shaft are both rotationally connected with the first box.

Optionally, the first clutch assembly comprises a gear and a first inner core wheel coaxially arranged inside the gear, a plurality of first rollers are uniformly arranged between the first inner core wheel and the inner wall of the gear at intervals along the circumferential direction of the first inner core wheel, and the first rollers can roll between the first inner core wheel and the gear; the first inner core wheel is fixedly connected with the planet carrier, and the gear is in transmission connection with the second clutch assembly.

Optionally, the first clutch assembly further comprises a first bearing coaxially disposed between the first inner core wheel and the gear and capable of abutting against the plurality of first rollers in an axial direction of the first inner core wheel.

Optionally, the second clutch assembly comprises an output gear and a second inner core wheel coaxially arranged inside the output gear, a plurality of second rollers are uniformly arranged between the second inner core wheel and the inner wall of the output gear at intervals along the circumferential direction of the second inner core wheel, and the second rollers can roll between the second inner core wheel and the output gear; the second inner center wheel is in key connection with the middle shaft, and the output gear is meshed with the gear and is in rotary connection with the middle shaft.

Optionally, a plurality of third rollers are uniformly arranged between the second inner core wheel and the inner wall of the output gear at intervals along the circumferential direction of the second inner core wheel, the third rollers can roll between the second inner core wheel and the output gear, the third rollers and the second rollers are alternately arranged, and the diameter of the third rollers is smaller than that of the second rollers.

Optionally, the rotor assembly comprises a rotor core and a plurality of magnetic steels embedded in the rotor core, and the plurality of magnetic steels are uniformly arranged at intervals along the circumferential direction of the rotor core; rotor core is provided with a plurality of knot points along axial direction's a terminal surface, and is a plurality of the knot point is followed rotor core's the even interval arrangement of circumference, adjacent two all be provided with one between the magnet steel the knot point, rotor core is provided with a plurality of recesses, and is a plurality of on another terminal surface along axial direction the recess is with a plurality of the position one-to-one of knot point.

Optionally, the rotor core is provided with a plurality of circular through holes at even intervals along the axial direction, and the plurality of circular through holes extend along the axial direction of the rotor core.

An electric power-assisted bicycle comprises the middle motor.

The invention has the beneficial effects that: according to the middle-mounted motor and the electric power-assisted bicycle provided by the invention, after the power is on, the rotor can rotate relative to the stator, so that the rotor can drive the sun gear to rotate, the sun gear drives the duplex planet gears to rotate in the inner gear ring, meanwhile, the duplex planet gears can drive the planet carrier to rotate, finally, the power transmission is carried out through the first clutch assembly and the second clutch assembly, the structure of the planet gear assembly is compact by adopting the matching of the duplex planet gears and the inner gear ring, meanwhile, the bearing capacity of the inner gear ring is large, the duplex planet gears can be accommodated in the inner gear ring, so that the middle-mounted motor is light in weight and small in size, meanwhile, compared with a reduction gear in a traditional motor, the transmission efficiency of the motor can be improved by adopting the planet gear assembly to carry out the power transmission, and the torque of the motor can be improved.

Drawings

Fig. 1 is a cross-sectional view of a mid-motor according to an embodiment of the present invention;

fig. 2 is an exploded view of a part of a mid-motor according to an embodiment of the present invention;

FIG. 3 is a cross-sectional view of a planetary gear assembly with a built-in motor according to an embodiment of the present invention;

FIG. 4 is a schematic view of the installation of the ring gear of the planetary gear assembly of the centrally-mounted motor according to one embodiment of the present invention;

FIG. 5 is a cross-sectional view of a first clutch assembly of a mid-motor provided in accordance with an embodiment of the present invention;

fig. 6 is an exploded view of a first clutch assembly of a mid-motor according to an embodiment of the present invention;

fig. 7 is a cross-sectional view of a second clutch assembly of a mid-motor according to an embodiment of the present invention;

fig. 8 is an exploded view of a second clutch assembly of the mid-motor according to an embodiment of the present invention;

fig. 9 is a schematic structural diagram of a rotor assembly of a centrally-mounted motor according to an embodiment of the present invention;

fig. 10 is a cross-sectional view of a first clutch assembly of a mid-motor according to a second embodiment of the present invention;

fig. 11 is an exploded view of a first clutch assembly of a mid-motor according to a second embodiment of the present invention.

In the figure:

1-a machine shell; 2-a stator;

3-a rotor assembly; 31-a rotor core; 311-a fastening point; 312-circular through hole; 313-a via; 32-magnetic steel;

4-sun gear;

5-a planetary gear assembly; 51-ring gear; 52-double planetary gear; 53-planet carrier; 54-connecting pin; 55-a support frame;

6-a first clutch assembly; 61-gear; 62-a first inner core wheel; 621-a first arc-shaped slot; 622-semi-arc groove; 63-a first roller; 64-a first bearing; 65-a baffle;

7-a second clutch assembly; 71-an output gear; 72-a second inner core wheel; 73-a second roller; 74-a second roller; 75-a cage;

8-the middle axis; 9-a first box; 10-a fluted disc; 11-a second box; 12-a bearing seat; 13-a controller; 14-a circuit board; 15-a scaffold; 16-oil seal.

Detailed Description

In order to make the technical problems solved, technical solutions adopted and technical effects achieved by the present invention clearer, the technical solutions of the embodiments of the present invention will be described in further detail below with reference to the accompanying drawings, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

In the description of the present invention, unless expressly stated or limited otherwise, the terms "connected," "connected," and "fixed" are to be construed broadly, e.g., as meaning permanently connected, removably connected, or integral to one another; can be mechanically or electrically connected; either directly or indirectly through intervening media, either internally or in any other relationship. The specific meanings of the above terms in the present invention can be understood in specific cases to those skilled in the art.

In the present invention, unless otherwise expressly stated or limited, "above" or "below" a first feature means that the first and second features are in direct contact, or that the first and second features are not in direct contact but are in contact with each other via another feature therebetween. Also, the first feature being "on," "above" and "over" the second feature includes the first feature being directly on and obliquely above the second feature, or merely indicating that the first feature is at a higher level than the second feature. A first feature being "under," "below," and "beneath" a second feature includes the first feature being directly under and obliquely below the second feature, or simply meaning that the first feature is at a lesser elevation than the second feature.

In the description of the present embodiment, the terms "upper", "lower", "left", "right", and the like are used based on the orientations and positional relationships shown in the drawings only for convenience of description and simplification of operation, and do not indicate or imply that the referred device or element must have a specific orientation, be configured and operated in a specific orientation, and thus, should not be construed as limiting the present invention. Furthermore, the terms "first" and "second" are used only for descriptive purposes and are not intended to have a special meaning.

The technical scheme of the invention is further explained by the specific implementation mode in combination with the attached drawings.

Example one

As shown in fig. 1-3, the centrally-mounted motor includes a casing 1, a stator 2, a rotor assembly 3, a sun gear 4, a planetary gear assembly 5, a first clutch assembly 6, a second clutch assembly 7, and a middle shaft 8, wherein the stator 2 is fixedly connected to the casing 1; the rotor component 3 is coaxially and rotatably arranged inside the stator 2; the sun gear 4 is fixedly arranged through the rotor component 3 and is rotationally connected with the machine shell 1; the planetary gear assembly 5 comprises an inner gear ring 51, a duplex planet gear 52 meshed with the inner gear ring 51 and a planet carrier 53 connected with the duplex planet gear 52, wherein the inner gear ring 51 is fixedly connected with the machine shell 1, the duplex planet gear 52 is meshed with the sun gear 4, and the planet carrier 53 is rotatably connected with the sun gear 4 and fixedly connected with the duplex planet gear 5; the first clutch component 6 is fixedly connected with the planet carrier 53; the second clutch component 7 is in transmission connection with the first clutch component 6; the central shaft 8 extends in the axial direction of the sun gear 4 and is connected to the second clutch assembly 7. It will be appreciated that when energized, the rotor assembly 3 is able to rotate relative to the stator 2, and the rotor assembly 3 is able to rotate the sun gear 4, the sun gear 4 drives the dual planetary gears 52 to rotate within the ring gear 51, meanwhile, the planet gears 52 of the double-clutch device can drive the planet carrier 53 to rotate, finally, power is transmitted through the first clutch assembly 6 and the second clutch assembly 7, by adopting the cooperation of the double planetary gears 52 and the ring gear 51, the planetary gear assembly 5 is compact, and the ring gear 51 has a large bearing capacity and can accommodate the double planetary gears 52 therein, and then can make this put light in weight, small of motor in, compare with the reduction gear in the traditional motor simultaneously, adopt planetary gear assembly 5 to carry out power transmission and can improve the transmission efficiency of this motor, and can be when reducing motor rotational speed, improve the moment of torsion of motor.

Specifically, as shown in fig. 1 to 3, in order to reduce the rotational friction, one end of the sun gear 4 is rotatably connected to the casing 1 through a bearing, a gasket is disposed between the bearing and the casing 1, an axial gap between the sun gear 4 and the casing 1 can be adjusted through the gasket, and the planet carrier 53 is rotatably engaged with the sun gear 4 through a deep groove ball bearing. In other embodiments, structures other than bearings may be used.

In this embodiment, the central motor is applied to an electric power-assisted bicycle, and as shown in fig. 2, the central motor further includes a toothed disc 10, the toothed disc 10 is connected to the central shaft 8, and the toothed disc 10 is connected to wheels of the electric power-assisted bicycle through a chain; meanwhile, cranks are arranged at two ends of the middle shaft 8, and pedals are arranged on the cranks, so that the electric power-assisted bicycle can also rotate the middle shaft 8 through the pedals to drive wheels to rotate. In other embodiments, the center motor can also be applied to other electric bicycles.

Optionally, as shown in fig. 1 and 3, the planetary gear assembly 5 further includes a connecting pin 54 and a supporting frame 55, the connecting pin 54 is rotatably disposed through the dual planetary gear 52 and has two ends respectively fixed to the planet carrier 53 and the supporting frame 55, and the supporting frame 55 is fixed to the first clutch assembly 6. It can be understood that when the sun gear 4 is in mesh transmission with the duplex planet gears 52, the duplex planet gears 52 can drive the planet carrier 53 to synchronously rotate while rotating in the internal gear ring 51, the planet carrier 53 drives the support frame 55 to rotate through the connecting pin 54, and then the support frame 55 can transmit power to the first clutch assembly 6. In the embodiment, the sun gear 4 penetrates through the planet carrier 53, the connecting pin 54 extends along the length direction of the sun gear 4 and is rotatably connected with the duplex planet gear 52 through two deep groove ball bearings, the two deep groove ball bearings are arranged at intervals, a gasket is arranged in the middle of the two deep groove ball bearings, the two deep groove ball bearings can be limited through the gasket, and two sides of the two deep groove ball bearings are respectively abutted to the planet carrier 53 and the support frame 55; in addition, in order to ensure reliable connection between the carrier 53 and the support 55, the carrier 53 and the support 55 are fixed by screws in addition to the connecting pins 54. In other embodiments, the planet carrier 53 and the supporting frame 55 may be fixed by other methods.

In this embodiment, the ring gear 51 and the duplex planet gears 52 are made of steel, and have better heat dissipation capacity and strength compared with common nylon materials, and the service lives of the ring gear 51 and the duplex planet gears 52 can be prolonged. In other embodiments, the inner gear ring 51 and the duplex planetary gear 52 may be made of other materials with good heat dissipation and high strength.

Optionally, as shown in fig. 1 and fig. 3, the mid-motor further includes a first case 9, the casing 1 and the ring gear 51 are respectively fixed on two sides of the first case 9, and the planet carrier 53 and the middle shaft 8 are both rotationally connected with the first case 9. Specifically, the sun gear 4 is inserted into the first box 9, one end of the middle shaft 8 is inserted into the first box 9 and is rotatably fitted with the first box 9 through a bearing, and the planet carrier 53 is rotatably fitted with the first box 9 through a bearing. Specifically, as shown in fig. 4, the ring gear 51 is fixed to the first case 9 by six step screws. In this embodiment, the centrally-mounted motor further includes a circuit board 14, and the circuit board 14 is fixed on the first box 9 and connected to the stator 2. The planetary gear assembly 5, the first clutch assembly 6 and the second clutch assembly 7 can be sealed and protected through the first box body 9 and the second box body 11, and the planetary gear assembly 5, the first clutch assembly 6 and the second clutch assembly 7 are prevented from being damaged; meanwhile, one end of the sun gear 4, which is far away from the machine shell 1, is rotatably connected with the second box body 11 through a bearing, and the second clutch component 7 is rotatably matched with the second box body 11 through a bearing. In other embodiments, the inner gear ring 51 may also be fixedly connected to the first box 9 by a pin and a snap spring.

Optionally, the mid-motor further includes a detection element, the detection element is fixedly connected to the middle shaft 8, and the detection element is used for detecting the torque of the middle shaft 8. In this embodiment, as shown in fig. 1, the centrally-mounted motor further includes a controller 13, the controller 13 is fixed to the first box 9 by screws, the detection element is a torque sensor, the torque sensor is electrically connected to the controller 13, the torque of the center shaft 8 is detected by the torque sensor and fed back to the controller 13, and the controller 13 can automatically control the centrally-mounted motor, so that the control is simple and convenient. The specific structure of the controller 13 is already the prior art, and will not be described herein. In other embodiments, the detection element may have other configurations.

Alternatively, as shown in fig. 1, 5 and 6, the first clutch assembly 6 includes a gear 61 and a first inner core wheel 62 coaxially disposed inside the gear 61, a plurality of first rollers 63 are disposed between the first inner core wheel 62 and the inner wall of the gear 61 at regular intervals along the circumferential direction of the first inner core wheel 62, and the first rollers 63 can roll between the first inner core wheel 62 and the gear 61; the first inner core wheel 62 is fixedly connected with the planet carrier 53, and the gear 61 is in transmission connection with the second clutch assembly 7. Specifically, the first inner core wheel 62 is connected to the support frame 55 by an a-type flat key. A plurality of first arc-shaped grooves 621 are arranged at intervals on the outer periphery of the first inner core wheel 62, and the first rollers 63 can roll in the first arc-shaped grooves 621. When the sun gear 4 rotates and drives the dual planetary gears 52 to rotate, the planet carrier 53 and the support frame 55 rotate to drive the first inner core wheel 62 to rotate synchronously, at this time, the first clutch component 6 is in a combined state, the first roller 63 can be tightly pressed between the first inner core wheel 62 and the gear 61 to drive the gear 61 to rotate, and therefore power is transmitted to the second clutch component 7; conversely, when the gear 61 rotates, the first clutch assembly 6 is in a disengaged state, i.e., the first rollers 63 can roll in the first arc-shaped grooves 621 on the outer periphery of the first inner core wheel 62, and power transmission between the first inner core wheel 62 and the gear 61 is not possible. It can be understood that the power transmission between the first inner core wheel 62 and the gear 61 is performed through the first roller 63, the transmission efficiency is high, the operation is smooth, and the noise is low.

Optionally, as shown in fig. 5 and 6, the first clutch assembly 6 further includes a first bearing 64, the first bearing 64 being coaxially disposed between the first inner core wheel 62 and the gear 61 and being capable of abutting with the plurality of first rollers 63 in the axial direction of the first inner core wheel 62. It is understood that both ends of the first roller 63 abut against the limit step of the gear 61 and the first bearing 64, respectively, and the first roller 63 can be limited in the axial direction of the first core wheel 62 by the first bearing 64, preventing the first roller 63 from coming off in the axial direction of the first core wheel 62. In other embodiments, other structures may be used in place of the first bearing 64.

Alternatively, as shown in fig. 1, 7 and 8, the second clutch assembly 7 includes an output gear 71 and a second inner core wheel 72 coaxially disposed inside the output gear 71, a plurality of second rollers 73 are disposed between the second inner core wheel 72 and the inner wall of the output gear 71 at regular intervals in the circumferential direction of the second inner core wheel 72, and the second rollers 73 can roll between the second inner core wheel 72 and the output gear 71; the second inner core wheel 72 is in key connection with the middle shaft 8, and the output gear 71 is meshed with the gear 61 and is in rotary connection with the middle shaft 8. Specifically, the output gear 71 is rotatably connected to the second case 11 through a bearing, and an output end of the output gear 71 penetrates through the second case 11 and is connected to the fluted disc 10; the output gear 71 is rotatably connected with the middle shaft 8 through a needle bearing, meanwhile, an oil seal 16 is further arranged outside the needle bearing, and the oil seal 16 is sleeved on the middle shaft 8 and can protect the needle bearing. It can be understood that the output gear 71 can drive the fluted disc 10 to rotate when rotating, and then can drive the wheels to rotate, so as to realize the purpose of electric riding.

Specifically, as shown in fig. 7 and 8, a plurality of third rollers 74 are provided between the second core wheel 72 and the inner wall of the output gear 71 at regular intervals in the circumferential direction of the second core wheel 72, the third rollers 74 are capable of rolling between the second core wheel 72 and the output gear 71, the third rollers 74 are alternately provided with the second rollers 73, and the diameter of the third rollers 74 is smaller than that of the second rollers 73. In this embodiment, a plurality of second arc-shaped grooves are provided at regular intervals in the outer peripheral portion of the second inner core wheel 72, and the third roller 74 and the second roller 73 can roll in the second arc-shaped grooves. When the first clutch assembly 6 is in the engaged state, i.e. the first inner core wheel 62 can drive the gear 61 to rotate, the gear 61 can drive the output gear 71 to rotate, and at this time, the second clutch assembly 7 is in the disengaged state, i.e. the third roller 74 and the second roller 73 can roll in the second arc-shaped groove, and cannot transmit power to the second inner core wheel 72; when the pedals are stepped on, the middle shaft 8 is rotated through the crank, the middle shaft 8 drives the second inner center wheel 72 to rotate, at the moment, the second clutch assembly 7 is in a combined state, namely the third roller 74 and the second roller 73 can be tightly propped between the second inner center wheel 72 and the output gear 71 to transmit power, so that the output gear 71 can be driven to rotate, the power is transmitted to the wheels through the fluted disc 10, and the wheels are driven to rotate.

Specifically, the second clutch assembly 7 further includes a cage 75, the cage 75 being coaxially disposed between the second inner core wheel 72 and the output gear 71 and being capable of abutting against the plurality of second rollers 73 and the plurality of third rollers 74 in the axial direction of the second inner core wheel 72. It can be understood that both ends of the second roller 73 and the plurality of third rollers 74 are respectively in contact with the output gear 71 and the retainer 75, and the second roller 73 and the third rollers 74 can be restrained in the axial direction of the second core wheel 72 by the retainer 75, and the second roller 73 and the third rollers 74 are prevented from coming off in the axial direction of the second core wheel 72. The second clutch component 7 adopts the mode that the second roller 73 is matched with the third roller 74, so that high transmission efficiency, smooth operation and low noise between the second inner core wheel 72 and the output gear 71 can be ensured.

In this embodiment, as shown in fig. 1, the mid-motor further includes a bracket 15, the bracket 15 is sleeved on the middle shaft 8 and can be abutted against the first box 9, the middle shaft 8 can be axially limited by the bracket 15, and the middle shaft 8 is prevented from axially moving to affect the use effect of the mid-motor; the gearbox is characterized by further comprising a bearing seat 12, wherein the bearing seat 12 is sleeved on the middle shaft 8 and fixedly connected with the first box body 9, and meanwhile, is rotatably connected with the output gear 71 through a bearing. In this embodiment, in order to reduce the weight of the centrally-mounted motor, the bracket 15 is made of a plastic material. In other embodiments, the frame 15 may be made of other materials.

Alternatively, as shown in fig. 9, the rotor assembly 3 includes a rotor core 31 and a plurality of magnetic steels 32 embedded inside the rotor core 31, where the plurality of magnetic steels 32 are uniformly spaced along the circumferential direction of the rotor core 31; a plurality of fastening points 311 are arranged on one end surface of the rotor core 31 in the axial direction, the fastening points 311 are uniformly arranged at intervals along the circumferential direction of the rotor core 31, and one fastening point 311 is arranged between two adjacent magnetic steels 32. Specifically, the other end surface of the rotor core 31 in the axial direction is provided with a plurality of grooves, and the plurality of grooves correspond to the positions of the plurality of fastening points 311 one to one. It can be understood that when a plurality of rotor cores 31 are stacked, the fastening point 311 of one rotor core 31 can be fastened in the groove of another rotor core 31 to form a self-fastening structure, so that the structure is stable. Meanwhile, the magnetic steel 32 is embedded in the rotor core 31, so that the loss of the middle motor can be reduced, the motor efficiency can be improved, and the cost can be saved. In this embodiment, the fastening point 311 is rectangular, and the groove is also rectangular. In other embodiments, the fastening point 311 and the groove may have other shapes such as a circle.

In this embodiment, a plurality of fastening points 311 are also provided at regular intervals along the circumferential direction of the rotor core 3 and near the axial center, and correspondingly, a plurality of grooves are also provided at the same position on the other end surface of the rotor core 31. With the above arrangement, structural stability when a plurality of rotor cores 31 are stacked on each other can be ensured. In other embodiments, the positions and the number of the fastening points 311 and the grooves may be changed according to different use requirements.

In this embodiment, a certain air gap is provided between one end of the magnetic steel 32 and the rotor core 31, and the magnetic leakage of the magnetic steel 32 can be reduced by the air gap, so that the shape and size of the air gap are not limited herein.

Alternatively, as shown in fig. 9, rotor core 31 is provided with a plurality of circular through holes 312 at regular intervals in the circumferential direction, and each of the plurality of circular through holes 312 extends in the axial direction of rotor core 31. Specifically, two circular through holes 312 are provided between two adjacent magnetic steels 32. The cogging torque of the motor can be reduced through the circular through hole 312, and the use performance of the motor is further improved. There is no limitation as to the size of the circular through-hole 312. In other embodiments, the number of the circular through holes 312 can be increased or decreased according to different requirements.

In this embodiment, as shown in fig. 9, rotor core 31 still is provided with the through-hole 313 that a plurality of intervals set up, and a plurality of through-holes 313 arrange and extend along rotor core 31's axial direction along rotor core 31's circumference, and the through-hole 313 sets up the one end of keeping away from the air gap at magnet steel 32, and the magnet steel groove at every magnet steel 32 place all communicates with two through-holes 313, can further reduce magnet steel 32 magnetic leakage through-hole 313, improves the life of motor.

The embodiment also provides an electric power-assisted bicycle, which has three use modes: an electric mode, a riding mode, and a power assist mode. When the electric bicycle is in an electric mode, after the motor is powered on, the rotor assembly 3 drives the sun gear 4 to rotate, the sun gear 4 drives the duplex planet gears 52 to rotate, the planet carrier 53 and the support frame 55 are further driven to rotate, the support frame 55 can drive the first inner core wheel 612 to synchronously rotate, at the moment, the first clutch assembly 6 is in a combined state, the first inner core wheel 62 drives the gear 61 to rotate through the first roller 63, the gear 61 drives the output gear 71 to rotate, at the moment, the second clutch assembly 7 is in a disengaged state, the third roller 73 and the fourth roller 74 cannot perform power transmission, the second inner core wheel 62 cannot move, the output gear 71 further drives the fluted disc 10 to rotate, and therefore the wheels can be driven to rotate. When the bicycle is in a riding mode, the motor is not powered on, the rotor assembly 3 cannot rotate, at the moment, the middle shaft 8 rotates through the crank by pedaling, the middle shaft 8 drives the second inner center wheel 72 to rotate, at the moment, the second clutch assembly 7 is in a combined state, the second inner center wheel 72 drives the output gear 71 to rotate through the second roller 73 and the third roller 74, the output gear 71 drives the gear 61 to rotate, at the moment, the first clutch assembly 6 is in a disengaged state, therefore, the first roller 63 cannot transmit power, the first inner center wheel 62 cannot move, the output gear 71 further drives the fluted disc 10 to rotate, and accordingly, the wheels can be driven to rotate. When the bicycle is in the assisting mode, the middle shaft 8 is rotated by pedaling the pedals, the middle shaft 8 drives the second inner wheel 72 to rotate, at this time, the second clutch assembly 7 is in the combination state, the second inner wheel 72 drives the output gear 71 to rotate through the second roller 73 and the third roller 74, at this time, after the torque of the middle shaft 8 collected by the detecting element is processed by the controller 13, the motor is controlled to start and operate through power distribution, the rotor assembly 3 drives the sun gear 4 to rotate, and further drives the double planetary gears 52 to rotate, the planet carrier 53 and the support frame 55 to rotate, and the first inner wheel 62 is driven to rotate, at this time, the first clutch assembly 6 is in the combination state, the first inner wheel 62 drives the gear 61 to rotate, and simultaneously transmits power to the output gear 71, in this mode, the pedals and the motor simultaneously act on the output gear 71 to drive the fluted disc 10 to rotate, thereby driving the wheels to rotate and achieving the effect of saving labor.

Example two

The difference between the present embodiment and the first embodiment is that, as shown in fig. 10 and 11, a plurality of semi-arc grooves 622 are further arranged at intervals on the periphery of the first inner core wheel 62, the first arc grooves 621 and the semi-arc grooves 622 are arranged alternately, and when the first roller 63 rolls in the first arc grooves 621, the semi-arc grooves 622 can be matched with the inner wall of the gear 61, so as to ensure free rolling of the first roller 63, improve the transmission efficiency of the first clutch assembly 6, and ensure quiet operation.

In the present embodiment, the first clutch unit 6 uses the baffle 65 instead of the first bearing 64, and both ends of the first roller 63 in the axial direction are respectively brought into contact with the stopper step of the gear 61 and the baffle 65, and the baffle 65 can restrict the first roller 63 in the axial direction of the first core wheel 62, thereby preventing the first roller 63 from coming off in the axial direction of the first core wheel 62. The structure of the first clutch assembly 6 can be simplified by using the baffle plate 65 instead of the first bearing 64, ensuring smoother operation.

It should be understood that the above-described embodiments of the present invention are merely examples for clearly illustrating the present invention, and are not intended to limit the embodiments of the present invention. Other variations and modifications will be apparent to persons skilled in the art in light of the above description. And are neither required nor exhaustive of all embodiments. Any modification, equivalent replacement, and improvement made within the spirit and principle of the present invention should be included in the protection scope of the claims of the present invention.

Claims (10)

1. A mid-motor, comprising:

a housing (1);

the stator (2), the said stator (2) is affixed to the said chassis (1);

the rotor assembly (3) is coaxially arranged inside the stator (2) in a rotating mode;

the sun gear (4) is fixedly arranged in the rotor component (3) in a penetrating mode and is in rotating connection with the machine shell (1);

the planetary gear assembly (5) comprises an inner gear ring (51), duplex planet gears (52) meshed with the inner gear ring (51) and a planet carrier (53) connected with the duplex planet gears (52), the inner gear ring (51) is fixedly connected with the machine shell (1), the duplex planet gears (52) are meshed with the sun gear (4), and the planet carrier (53) is rotationally connected with the sun gear (4) and fixedly connected with the duplex planet gears (52);

the first clutch component (6), the first clutch component (6) is fixedly connected with the planet carrier (53);

a second clutch assembly (7), wherein the second clutch assembly (7) is in transmission connection with the first clutch assembly (6);

a central shaft (8), wherein the central shaft (8) extends along the axial direction of the sun gear (4) and is connected with the second clutch component (7).

2. The centrally-mounted motor according to claim 1, wherein the planetary gear assembly (5) further comprises a connecting pin (54) and a supporting frame (55), the connecting pin (54) is rotatably inserted into the double planetary gear (52) and two ends of the connecting pin are fixedly connected with the planet carrier (53) and the supporting frame (55), respectively, and the supporting frame (55) is fixedly connected with the first clutch assembly (6).

3. The centrally-mounted motor according to claim 1, further comprising a first box (9), wherein the casing (1) and the ring gear (51) are respectively fixed on two sides of the first box (9), and the planet carrier (53) and the middle shaft (8) are both rotationally connected with the first box (9).

4. The centrally placed electric machine according to any one of claims 1-3, characterised in that the first clutch assembly (6) comprises a gear wheel (61) and a first inner core wheel (62) coaxially arranged inside the gear wheel (61), a plurality of first rollers (63) are arranged between the first inner core wheel (62) and the inner wall of the gear wheel (61) at even intervals in the circumferential direction of the first inner core wheel (62), and the first rollers (63) can roll between the first inner core wheel (62) and the gear wheel (61); the first inner core wheel (62) is fixedly connected with the planet carrier (53), and the gear (61) is in transmission connection with the second clutch component (7).

5. The centrally placed electric machine according to claim 4, characterised in that the first clutch assembly (6) further comprises a first bearing (64), the first bearing (64) being coaxially arranged between the first core wheel (62) and the gear wheel (61) and being capable of abutting with the plurality of first rollers (63) in the axial direction of the first core wheel (62).

6. The centrally-mounted motor according to claim 4, characterized in that the second clutch assembly (7) comprises an output gear (71) and a second inner core wheel (72) coaxially arranged inside the output gear (71), a plurality of second rollers (73) are uniformly arranged between the second inner core wheel (72) and the inner wall of the output gear (71) at intervals along the circumferential direction of the second inner core wheel (72), and the second rollers (73) can roll between the second inner core wheel (72) and the output gear (71); the second inner core wheel (72) is in key connection with the middle shaft (8), and the output gear (71) is meshed with the gear (61) and is in rotary connection with the middle shaft (8).

7. The centrally-mounted motor according to claim 6, characterized in that a plurality of third rollers (74) are provided between the second inner core wheel (72) and the inner wall of the output gear (71) at regular intervals in the circumferential direction of the second inner core wheel (72), the third rollers (74) are capable of rolling between the second inner core wheel (72) and the output gear (71), the third rollers (74) and the second rollers (73) are alternately arranged, and the diameter of the third rollers (74) is smaller than that of the second rollers (73).

8. The centrally-mounted motor according to any one of claims 1 to 7, wherein the rotor assembly (3) comprises a rotor core (31) and a plurality of magnetic steels (32) embedded in the rotor core (31), and the plurality of magnetic steels (32) are uniformly arranged at intervals along the circumferential direction of the rotor core (31); rotor core (31) are provided with a plurality of knot points (311) on the terminal surface along axial direction, and are a plurality of knot point (311) are followed the even interval arrangement of circumference of rotor core (31), adjacent two all be provided with one between magnet steel (32) knot point (311), rotor core (31) are provided with a plurality of recesses, and are a plurality of on another terminal surface along axial direction the recess is with a plurality of the position one-to-one of knot point (311).

9. The centrally-mounted motor according to claim 8, characterized in that the rotor core (31) is provided with a plurality of circular through holes (312) at regular intervals in a circumferential direction, and each of the plurality of circular through holes (312) extends in an axial direction of the rotor core (31).

10. An electrically assisted bicycle, characterized in that it comprises a mid-motor according to any of claims 1-9.

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