Hub motor and power-assisted bicycle

Abstract

The utility model provides a hub motor and a power-assisted bicycle. The hub motor comprises a main shaft, a motor, a double-planetary reducer and a hub shell. The motor comprises a stator and a rotor. The stator is fixedly connected with the main shaft. The double-planetary reducer comprises a first-stage planetary gear train, a second-stage planetary gear train and an inner gear ring, the inner gear ring is fixedly connected with the stator, planetary gears in the first-stage planetary gear train and the second-stage planetary gear train are both meshed with the inner gear ring, the rotor drives the first-stage planetary gear train to rotate, and the first-stage planetary gear train and the second-stage planetary gear train are in one-way clutch transmission connection. The hub shell is rotationally connected with the main shaft and fixedly connected with an output piece in the second-stage planetary gear train. According to the hub motor, the reduction ratio of the double planetary reducers is larger, the motor with the higher rotating speed can be adopted, the diameter of the motor with the higher rotating speed is smaller, the radial size can be reduced, meanwhile, the mass can be greatly reduced, and therefore the overall size and mass of the hub motor are smaller.

Description

TECHNICAL FIELD

[0001] The utility model belongs to the wheel hub motor drive field, especially relate to a wheel hub motor and power-assisted bicycle. BACKGROUND

[0002] Electric vehicles are widely used at home and abroad, among them, power-assisted bicycles are very popular, power-assisted bicycles not only have the pedal function of bicycles, but also have the power-assisted driving function of electric vehicles, so that power-assisted bicycles do not cause too much burden on the rider's physical strength, and the power-assisted size can be adjusted according to the road conditions, which is convenient for users to use. At present, the commonly used one is a wheel hub motor.

[0003] For the wheel hub motor, the current assembly structure of the wheel hub motor is not reasonable, resulting in large volume, large weight and high energy consumption of the motor. UTILITY MODEL CONTENTS

[0004] The technical problem to be solved by the utility model lies in providing a wheel hub motor, aiming at solving the assembly problem in the wheel hub motor, including the structure assembly problem and the wiring problem caused by the structure assembly problem.

[0005] To solve the above technical problems, the utility model provides a wheel hub motor, which comprises:

[0006] A main shaft;

[0007] A motor comprising a stator and a rotor, the stator is fixedly connected with the main shaft, and the stator drives the rotor to rotate;

[0008] A double-planetary reducer comprising a primary planetary gear train, a secondary planetary gear train and an inner ring gear, the inner ring gear is fixedly connected with the stator, the planetary gears in the primary planetary gear train and the secondary planetary gear train are all engaged with the inner ring gear, the rotor drives the primary planetary gear train to rotate, and the primary planetary gear train and the secondary planetary gear train are connected in one-way clutch transmission;

[0009] A wheel hub shell, which is rotationally connected with the main shaft and fixedly connected with an output member in the secondary planetary gear train, and the wheel hub shell is used for externally connecting the spokes of a driving wheel.

[0010] In one of the embodiments, the primary planetary gear train comprises a primary sun gear, a primary planetary gear and a primary planet carrier, the primary sun gear is fixedly connected with the rotor, the primary planetary gear is installed on the primary planet carrier, the primary planet carrier is rotationally connected with the main shaft, the primary planetary gear is engaged with the primary sun gear, the rotor drives the primary sun gear to rotate, the primary sun gear drives the primary planet carrier to run at a reduced speed through the primary planetary gear, and the primary speed reduction is realized;

[0011] The secondary planetary gear train comprises a secondary sun gear, a secondary planetary gear and a secondary planet carrier, the secondary sun gear is rotationally connected with the main shaft and is connected with the primary planet carrier through one-way clutch transmission, and the secondary sun gear is engaged with the secondary planetary gear, the secondary planetary gear is installed on the secondary planet carrier, the secondary planet carrier is rotationally connected with the main shaft, and the secondary planetary gear is engaged with the secondary sun gear;

[0012] The primary planet carrier drives the secondary sun gear to rotate, the secondary sun gear drives the secondary planet carrier to run at a reduced speed through the secondary planetary gear, and secondary speed reduction is realized.

[0013] In one of the embodiments, the stator comprises a base which is sleeved and fixed on the outer side of the main shaft and a stator bracket which is arranged on the outer circumferential surface of the base, the stator bracket is provided with a winding, and the base is provided with a clearance cavity;

[0014] The rotor comprises a rotating part, a first connecting part and a magnetic steel, the rotating part is sleeved on the outer side of the main shaft and located in the clearance cavity, a third bearing is arranged between the rotating part and the inner wall of the clearance cavity, and the rotor rotates relative to the stator through the third bearing; the rotating part is provided with a stop part at one end which is close to the base along the axial direction of the main shaft, the first connecting part extends radially and outwardly from the outer wall of the rotating part, and the magnetic steel is fixed to the first connecting part and surrounds the outer side of the winding.

[0015] In one of the embodiments, the primary planet carrier and the secondary sun gear are connected through a one-way bearing, the one-way bearing comprises an inner ring and an outer ring, one of the inner ring and the outer ring is fixedly connected with the primary planet carrier, and the other is fixedly connected with the secondary sun gear, so that the secondary sun gear is configured to be able to rotate independently of the primary planet carrier.

[0016] In one of the embodiments, a first ring, a second ring and a third ring are coaxially arranged on the side of the secondary sun gear which is close to the primary planet carrier, and the rings are spaced from each other from inside to outside.

[0017] The first ring and the main shaft are spaced from each other to accommodate a second bearing, the secondary sun gear is rotationally connected with the main shaft through the second bearing, one side of the second ring which is away from the main shaft is used for bearing the inner ring of the one-way bearing, so as to realize that the one-way bearing drives the secondary sun gear to rotate, and the third ring abuts against the outer ring to limit the axial displacement of the outer ring.

[0018] In one of the embodiments, the one-way bearing further comprises two wear-resistant sheets, the two wear-resistant sheets are respectively located on the two sides of the roller of the one-way bearing, one of the wear-resistant sheets is close to the primary planet carrier, and the other is close to the secondary sun gear.

[0019] In one of the embodiments, the primary planetary gear train further comprises a gland, the gland is fixedly connected with the primary planet carrier, and the primary planetary gear is located between the gland and the planet carrier.

[0020] The cover is rotatably connected with the primary sun gear through a first bearing, and the cover is provided with a limiting portion which is attached to the side of the first bearing close to the primary planetary gear to limit the position of the first bearing and the primary sun gear.

[0021] In one of the embodiments, a torque sensor is further included, the motor is provided with a controller, the torque sensor is in communication connection with the controller, the torque sensor is used to be connected with the pedal transmission to sense the external pedaling force and generate corresponding electrical signals, and the controller can receive the electrical signals to adjust the output torque of the motor.

[0022] The application provides another hub motor for a driving wheel of a power-assisted bicycle, comprising:

[0023] The main shaft is provided with a flat portion extending along the length direction thereof on the outer circumferential surface;

[0024] The planetary reducer is sleeved on the main shaft and rotatably connected with the main shaft;

[0025] The hub shell is rotatably connected with the main shaft, the hub shell is used to be connected with spokes of the driving wheel, and the output member in the planetary reducer is fixedly connected with the hub shell;

[0026] The motor comprises a stator and a rotor, the stator is fixedly connected with the main shaft, the stator drives the rotor to rotate, and the rotor is fixedly connected with the input member in the planetary reducer to drive the hub shell to rotate through the planetary reducer;

[0027] The torque sensor comprises a body and a signal transmission line, the signal transmission line is in communication connection with the body, the body, the planetary reducer and the motor are arranged in sequence along the length direction of the main shaft in the axial direction of the main shaft, the body is used to sense the external pedaling force and generate corresponding electrical signals, and the signal transmission line passes through the flat portion and is electrically connected with the stator to adjust the rotating speed of the rotor.

[0028] In one of the embodiments, a pressing plate is further included, the width of the pressing plate is smaller than the width of the flat portion, the pressing plate is fixedly connected with the flat portion and is provided with a channel for the flexible cable to pass through.

[0029] In one of the embodiments, the planetary reducer is a double planetary reducer, the double planetary reducer comprises a primary planetary gear train and a secondary planetary gear train, and the primary planetary gear train and the secondary planetary gear train are rotatably connected through a one-way bearing.

[0030] The application provides a power-assisted bicycle, which comprises the hub motor provided in any of the embodiments and further comprises a driving wheel, the hub motor is located at the center position of the driving wheel, the driving wheel comprises a plurality of spokes, the hub shell in the hub motor is connected with the plurality of spokes, and the main shaft in the hub motor is fixedly connected with the central shaft of the driving wheel.

[0031] The utility model provides two kinds of wheel hub motor, the first kind wheel hub motor assembles double planetary reducer, has improved transmission ratio and reduced the use space of power assisted bicycle radial simultaneously. Through the one way bearing is installed between primary planetary carrier and second sun gear, make the one way bearing avoid high rotating speed close to rotor and big torque close to wheel hub shell simultaneously, make the one way bearing stress and rotating speed are more balanced, improve the service life under the condition of equal material, make the overall service life of wheel hub motor is longer, thereby reduced the economic cost of user. The second kind wheel hub motor sets up flat position to main shaft, it is convenient to torque sensor wiring, and the planetary reducer whether fixed or not fixed does not influence torque sensor placement circuit. Two kinds of wheel hub motor provided by the application can be used in combination, compared with prior art wheel hub motor, the structure is more reasonable, wiring is more reasonable, can reduce overall size, power assisted function is stronger, and service life is longer. BRIEF DESCRIPTION OF DRAWINGS

[0032] Figure 1 It is the overall structure schematic diagram of wheel hub motor in the utility model embodiment;

[0033] Figure 2 It is Figure 1 It is the half cut surface graph of wheel hub motor in the embodiment;

[0034] Figure 3 It is the assembly schematic diagram of double planetary gear train;

[0035] Figure 4 It is Figure 1 It is the internal structure schematic diagram of the embodiment;

[0036] Figure 5 It is the structure schematic diagram of main shaft;

[0037] Figure 6 It is Figure 1 It is the explosion schematic diagram of wheel hub motor in the embodiment.

[0038] In the drawings, various reference signs represent: main shaft 100;Flat position 110;Motor 200;Stator 210;Stator bracket 211;Winding 212;Rotor 220;Rotating part 221;First connecting part 222;Stop part 223;Magnetic steel 224;Steel ring 225;Inner gear ring 310;Primary sun gear 311;Primary planetary gear 312;Primary planetary carrier 313;Gland 314;First end 3141;Second end 3142;Second sun gear 321;First ring 3211;Second ring 3212;Third ring 3213;Second planetary gear 322;Second planetary carrier 323;Wheel hub shell 400;One way bearing 500;Inner ring 510;Outer ring 520;Wear plate 530;Roller assembly 540;Torque sensor 600;Compression sheet 610;

[0039] First bearing 11; second bearing 12; third bearing 13; fourth bearing 14; end cover 15. DETAILED DESCRIPTION

[0040] In order to make the purpose, technical scheme and advantages of the utility model more clearly, the utility model is further described in detail below in combination with the drawings and examples. It should be understood that the specific examples described herein are only used to explain the utility model and not to limit the utility model.

[0041] At present, the common wheel hub motor mainly includes a motor, a single planetary reducer and a wheel hub shell. The working principle of the wheel hub motor is that the motor outputs power through the rotation of the rotor, the torque is reduced and enlarged by the single planetary reducer to the wheel hub shell, so that the wheel hub shell rotates, the wheel hub shell is used to connect the spokes of the drive wheel on the power-assisted bicycle, so that the drive wheel rotates, and the power-assisted bicycle advances.

[0042] Referring to Figure 1 and Figure 2 , Figure 1 The overall structure diagram of the wheel hub motor is shown, Figure 2 The half-section view of the wheel hub motor is shown. In one embodiment, the application provides a new wheel hub motor, mainly including a main shaft 100, a motor 200, a double planetary reducer and a wheel hub shell 400. The motor 200 includes a stator 210 and a rotor 220, the stator 210 is fixedly connected with the main shaft 100, and the stator 210 drives the rotor 220 to rotate. The planetary reducer adopts a double planetary reducer, including a primary planetary gear train, a secondary planetary gear train and an inner ring gear 310, the inner ring gear 310 is fixedly connected with the stator 210, the planetary gears in the primary planetary gear train and the secondary planetary gear train are engaged with the inner ring gear 310, the rotor 220 drives the primary planetary gear train to rotate, and the primary planetary gear train and the secondary planetary gear train are connected in one-way clutch transmission.

[0043] At present, the commonly used wheel hub motor mostly uses a single planetary reducer, which is commonly called a primary planetary reducer. In order to distinguish the primary planetary gear train in the double planetary reducer of the application, the primary planetary reducer is called a single planetary reducer to avoid increasing the difficulty of reading. The biggest disadvantage of the single planetary reducer compared with the double planetary reducer is that the speed reduction ratio is low. Under the condition of the same torque output, the volume and weight of the double planetary reducer are significantly better, and the applicability is stronger. Therefore, the double planetary reducer can adopt a motor 200 with higher speed, and the diameter of the rotor 220 of the high-speed motor 200 is small. This design makes the centrifugal force on the embedded winding smaller when rotating at high speed, so it is suitable for high-speed operation. At the same time, the weight of the wheel hub motor is mostly reflected in the motor 200, so the reduction of the volume of the motor 200 can effectively reduce the overall weight, and the high-speed motor 200 has lower energy consumption than the low-speed motor.

[0044] The hub motor assembly double planetary reducer provided by the application improves the reduction ratio and reduces the radial space of the power-assisted bicycle, thereby reducing the overall space occupation and making the transmission structure more compact.

[0045] In the application, the motor includes a stator 210 and a rotor 220, the stator 210 includes a base sleeved on and fixed to the outer side of the main shaft 100 and a stator bracket 211 arranged on the outer circumferential surface of the base, the stator bracket 211 is provided with a winding 212, and the winding 212 can generate an electromagnetic field through power supply. Figure 2 The base has a clearance cavity for the main shaft 100 to pass through and for accommodating part of the structure of the rotor 220. The rotor 220 includes a rotating part 221 sleeved on the main shaft 100 and located in the clearance cavity, a third bearing 13 is arranged between the rotating part 221 and the inner wall of the clearance cavity, and in order to position the third bearing 13, the rotating part 221 is provided with a stop part 223 at one end close to the base along the axial direction of the main shaft. The outer edge of the stop part 233 exceeds the outer edge of the rotating part 221, so as to limit the third bearing 13 between the stator 210 and the rotor 220. The rotor 220 further includes a first connecting part 222 extending radially outward from the outer wall of the rotating part 221 and a magnetic steel 224 fixed to the first connecting part 222 and surrounding the outside of the winding. When the motor is powered, the winding 212 generates current to form an electromagnetic field, the electromagnetic field generates a rotating force on the magnetic steel 224, so that the magnetic steel 224 drives the rotor 220 to rotate around the main shaft 100, and the size of the current and the magnetic force of the magnetic steel 224 determine the rotation speed of the rotor 220.

[0046] In the above embodiment, the rotor 220 and the stator 210 make full use of the radial space and reduce the length in the axial direction, so that the overall volume of the motor is smaller.

[0047] Referring to Figure 2 Preferably, since the length of the stator bracket 211 on the main shaft 100 is longer, the third bearing 13 is provided with two third bearings 13 to make the rotation of the rotor 220 more stable. The two third bearings 13 are arranged at two sides of the stator bracket 211 in the axial direction and are separated by a retaining ring.

[0048] Specifically, referring to Figure 3 , Figure 3 The assembly structure of the primary planetary gear train and the secondary planetary gear train is shown, Figure 3The inner ring 310 and the hub shell 400 are omitted in the present application. The primary planetary gear train in the present application comprises a primary sun gear 311, a primary planetary gear 312 and a primary planet carrier 313. The primary sun gear 311 is fixedly connected with the rotor 220. The primary planetary gear 312 is installed on the primary planet carrier 313. The primary planet carrier 313 is rotationally connected with the main shaft 100. The primary planetary gear 312 is engaged with the primary sun gear 311. The rotor 220 drives the primary sun gear 311 to rotate. The primary sun gear 311 drives the primary planet carrier 313 to run at a reduced speed through the primary planetary gear 312, so as to realize primary speed reduction.

[0049] The primary sun gear 311 comprises a tooth portion and a second connecting portion. The tooth portion and the second connecting portion are in an integral structure. The second connecting portion is located in the interval between the rotor 220 and the main shaft 100 and is in interference fit with the rotor 220. The end of the second connecting portion at least coincides with the first connecting portion 222 in the radial direction to increase the connecting strength. The tooth portion is engaged with the primary planetary gear 312.

[0050] Preferably, in one of the embodiments, the structure of the rotor 220 can be known from Figure 3 , in combination with Figure 2 , from Figure 2 . Specifically, the rotating portion 221 of the rotor 220 and the outer wall of the main shaft 100 have an interval therebetween. The end of the rotating portion 221 away from the stop portion 223 protrudes out of the first connecting portion 222. The interval is used to accommodate the second connecting portion of the primary sun gear 311.

[0051] Preferably, in one of the embodiments, the thickness of the protruding part of the rotating portion 221 of the rotor 220 is less than that of the part in the accommodation cavity. In this way, the space above the protruding part can be increased to accommodate the gland 314. Since the rotor 220 rotates at a high speed, it will interfere with the rotation of the primary planet carrier 313 on the side of the rotor 220. The gland 314 can separate the rotor 220 and the primary planet carrier 313, so as to avoid the interference. In addition, since the primary sun gear 311 is in interference fit with the rotating portion 221, the rotating portion 221 with a smaller thickness is more conducive to assembly than the rotating portion 221 with a larger thickness.

[0052] Specifically, the gland 314 is fixedly connected with the primary planet carrier 313. In order to make the position of the gland 314 in the space more stable, the first bearing 11 is arranged between the gland 314 and the rotating portion 221. The specific structure of the gland 314 can be known from the cross section in Figure 2 . The gland 314 comprises a first end 3141 abutting against the first bearing 11, a second end 3142 used for fixedly connecting with the primary planet carrier 313 and a third end 3143 located between the first bearing 11 and the primary planetary gear 312. Figure 3The first end 3141, the second end 3142 and the third end are integrally cast. The first end 3141 is used to realize the rotational connection of the gland 314 relative to the main shaft 100, the first end 3141 is fixedly connected with the first bearing 11, and the second end 3142 abuts against the primary planetary gear 312 on the right side to cope with the axial displacement of the primary planetary carrier 313 when rotating under the action of the force of the inner ring gear 310.

[0053] In the above embodiment, the engagement mode is helical engagement, which is a gradual engagement mode. The helical engagement has good engagement, stable transmission, low noise, high coincidence degree, reduced load of each pair of gears, improved load bearing capacity of the gears, and the least number of teeth without undercut. Compared with straight engagement, the assembly structure of helical engagement is more compact. Since the helical engagement generates an axial force, the second end 3142 of the gland 314 limits the displacement of the primary planetary gear 312 in the axial direction.

[0054] In other embodiments, straight engagement mode can also be used for transmission.

[0055] Preferably, in one embodiment, the primary planetary gears 312 are provided in three and are equally angularly spaced outside the tooth portion. Each primary planetary gear 313 is engaged with the tooth portion and the inner ring gear 310. The primary planetary carrier 313 is coaxially sleeved outside the main shaft 100. Figure 3 The primary planetary gears 312 are respectively sleeved on the protruding shafts of the primary planetary carrier 313. In addition to the three protruding shafts corresponding to the three primary planetary gears 312, the primary planetary carrier 313 is also provided with three connecting shafts fixedly connected with the gland 314 to drive the rotation of the gland 314.

[0056] The secondary planetary gear train includes a secondary sun gear 321, a secondary planetary gear 322 and a secondary planetary carrier 323. The secondary sun gear 321 is rotationally connected with the main shaft 100 and is in one-way clutch transmission connection with the primary planetary carrier 313. The secondary sun gear 321 is engaged with the secondary planetary gear 322. The secondary planetary gear 322 is installed on the secondary planetary carrier 323. The secondary planetary carrier 323 is rotationally connected with the main shaft 100. The secondary planetary gear 322 is engaged with the secondary sun gear 321. The primary planetary carrier 313 drives the rotation of the secondary sun gear 321. The secondary sun gear 321 drives the secondary planetary carrier 323 to run at a reduced speed through the secondary planetary gear 322, thereby realizing secondary speed reduction.

[0057] In the above embodiment, the primary planetary carrier 313 and the secondary sun gear 321 are respectively the output of the primary planetary gear train and the input of the secondary planetary gear train, so they are in one-way transmission connection.

[0058] The biggest feature of the planetary reducer is that the sun gear, the planet carrier and the inner ring 310 can be used as power input and power output, so in other embodiments, the inner ring 310 can also be used as the power output of the first planetary carrier 313, and the inner ring 310 is connected with the second sun gear 321 in the second planetary gear train in one-way transmission. It can be understood that if the second planet gear 322 in the second planetary gear train needs to revolve, another fixed inner ring 310 needs to be installed. Since the inner ring 310 in the present application is a fixed part, two planetary reducers can share one inner ring 310.

[0059] In one embodiment, the first planetary carrier 313 and the second sun gear 321 are connected in transmission through the one-way bearing 500, which includes an inner ring 510 and an outer ring 520, one of which is fixedly connected with the first planetary carrier 313, and the other is fixedly connected with the second sun gear 321, so that the second sun gear 321 is configured to be able to rotate independently of the first planetary carrier 313.

[0060] Specifically, in the present application, the outer ring 520 is fixedly connected with the first planetary carrier 313, and the inner ring 510 is fixedly connected with the second sun gear 321, and the needle roller assembly 540 is arranged between the inner ring 510 and the outer ring 520. Of course, the needle roller can be replaced by a ball or a roller, etc. The one-way bearing 500 is a prior art device, and the working principle thereof will not be described in detail. When the first planetary carrier 313 rotates, it can drive the second sun gear 321 to rotate, and when the second sun gear 321 rotates, it does not need the first planetary carrier 313 to rotate, which is similar to ratchet transmission, so as to facilitate independent cycling of the user.

[0061] Referring to Figure 2 , in combination Figure 3 , the specific structure of the second sun gear 321 can be determined, and from Figure 3 , it can be seen that the second sun gear 321 is coaxially provided with a first ring 3211, a second ring 3212 and a third ring 3213 from inside to outside in the side close to the first planetary carrier. There is a gap between the first ring 3211 and the main shaft 100 for accommodating the second bearing 12, and the first ring 3211 and the second bearing 12 are in interference fit, so as to realize the relative rotation of the second sun gear 321 and the main shaft 100. In order to position the second bearing 12, referring to Figure 2 , in addition to the shaft shoulder of the main shaft 100, the side of the first planetary carrier 313 close to the second bearing 12 protrudes from the end face of the first planetary carrier 313 and is provided with a limiting portion, so as to position the second bearing 12 together with the shaft shoulder of the main shaft 100. After assembly is completed, the wheel hub shell 400 realizes the fixed connection relationship of the overall structure.

[0062] The second ring 3212 bears the inner ring 510 of the one-way bearing 500 on the side away from the main shaft 100, so that the one-way bearing 500 drives the second sun gear 321 to rotate. The third ring 3213 is attached to the outer ring 520. Depending on the shape of the outer ring 520, the third ring 3213 is located in the stepped space on the side of the outer ring 520 facing the third ring 3213, so that the structure of the transmission system is more compact. Figure 2 As can be seen from the figure, the outer ring has a stepped space on the side facing the third ring 3213, and the third ring 3213 is located in the stepped space, so that the structure of the transmission system is more compact.

[0063] In the prior art, the single planetary reducer has the following disadvantages: the one-way bearing 500 can only be connected to the rotor 220 and the input member of the single planetary reducer, or connected to the output member of the single planetary reducer and the hub shell 400. In the first connection, the rotor 220 rotates at a high speed, and in the second connection, the output member of the single planetary reducer is reduced in torque, which affects the service life of the one-way bearing 500 or requires a higher quality of the one-way bearing 500. In the present application, the double planetary reducer is used to install the one-way bearing 500 between the first planetary reducer and the second planetary reducer, so that the one-way bearing 500 is simultaneously away from the high speed of the rotor 220 and the large torque of the hub shell 400, and the stress and speed of the one-way bearing 500 are more balanced, the service life of the one-way bearing 500 is improved by the different installation positions, the overall service life of the in-wheel motor is longer, and the economic cost of the user is reduced.

[0064] The number of the second planetary gears 322 is preferably different from that of the first planetary gears 312, and preferably co-prime, so that the internal wear of the in-wheel motor is more evenly distributed with the increase of the use time. Like the first planetary gear system, the second planetary gears 322 are sleeved on the second planetary carrier 323 and rotatably connected to the second planetary carrier 323. The second planetary carrier 323 is provided with a plurality of bolt holes for fixed connection with the end cover 15. Since the second planetary carrier 323 is positioned by the end cover 15, it does not need to be positioned by the pressure cover 314.

[0065] In the above embodiment, referring to Figure 3 The connection between the first planetary gears 312 and the first planetary carrier 313, and the connection between the second planetary carrier 322 and the second planetary carrier 323 are both rotatable connections through bearings. The end portions of the protruding shafts of the first planetary carrier 313 and the second planetary carrier 323 are expanded in diameter by a hot melting method to limit the disengagement of the first planetary gears 312 and the first planetary carrier 313, thereby completing the rotational assembly.

[0066] In other embodiments, the inner ring 510 can be fixedly connected to the first planetary carrier 313, and the outer ring 520 can be fixedly connected to the second sun gear 321.

[0067] Preferably, referring to Figure 2 and Figure 3In one of the embodiments, the one-way bearing 500 further comprises two wear-resistant plates 530, which are respectively located on both sides of the rollers of the one-way bearing 500, one of which is close to the primary planetary carrier 313, and the other of which is close to the secondary sun gear 321, so as to prevent the one-way bearing 500 from wearing the structure on both sides when moving.

[0068] Specifically, referring to Figure 2 and Figure 3 In the above embodiment, the end surface of the primary planetary carrier 313 towards the one-way bearing 500, and the end surface of the secondary sun gear 321 between the second ring 3212 and the third ring 3213 are both provided with grooves, the positions of the two grooves are flush with the needle roller assembly in the one-way bearing 500, and the two grooves are used to accommodate the wear-resistant plates 530.

[0069] Figure 4 The exploded view of the hub motor after removing the hub shell 400 and the inner ring 310 is shown, from Figure 4 It can be seen that, in addition to the primary planetary gear 312 and the secondary planetary gear 322 being exposed for meshing with the inner ring 310, other parts are compact in structure, closely in transmission, and good in sealing, thereby increasing the space occupancy and reducing the overall volume of the hub motor.

[0070] Preferably, referring to Figure 1 or Figure 2 The hub motor further comprises a torque sensor 600, and a controller (not shown in the figure) is arranged on the motor 200, in order to clearly see the structure of the torque sensor 600, Figure 1 and Figure 4 The rotating assembly of the torque sensor is not shown in Figure 6 The exploded view of the hub motor is shown, which shows the rotating part of the torque sensor 600. The torque sensor 600 is in communication connection with the controller, and the torque sensor 600 is used to be connected with the pedal drive to sense the size of the external pedaling force and generate a corresponding electrical signal, and the controller can accept the electrical signal to adjust the output torque of the motor 200.

[0071] Similarly, the torque sensor 600 is an existing device, and the torque sensor 600 is usually connected with a flywheel or a common toothed disc, and is connected with the pedal through a chain. When the user rides, the torque sensor 600 can sense the specific pedaling force and transmit a corresponding electrical signal to the controller of the motor 200, and the controller can be used to control the size of the magnetic field of the stator 210 or the size of the winding 212 current in the motor 200, thereby adjusting the speed of the rotor 220.

[0072] Referring to Figure 2 and Figure 5 , Figure 5The structural schematic diagram of the main shaft 100 is shown. In one of the embodiments, the torque sensor 600 and the motor 200 are respectively located at two ends of the main shaft 100, and other parts such as double planetary reduction gear trains are located in the middle. The main shaft 100 is provided with a flat position 110, that is, when the main shaft 100 is machined, a flat area is milled on the outer circumferential surface along the length direction of the main shaft 100. Since the main shaft 100 and other parts are in a rotating relationship or a fixed relationship, a channel is formed between the flat area and other parts. The torque sensor 600 has a signal transmission line (not shown in the figure), and the signal transmission line passes through the channel to communicate with the controller on the motor 200.

[0073] Since the cable diameter of the motor 200 is relatively thick, when the motor 200 and the torque sensor 600 are located at the same end, the cable occupies a relatively large space. Since the torque sensor 600 needs to be externally connected to a flywheel, it is more beneficial to improve the space utilization to locate the motor 200 and the torque sensor 600 at two ends of the main shaft 100. The torque sensor 600 is in communication with the motor 200 through the flat position 110 of the main shaft 100, which not only does not increase the overall size, but also makes the exposed wire of the hub motor less and the whole more beautiful.

[0074] Preferably, since the signal transmission line is a flexible cable, in order to avoid interference with rotating parts, the present application adopts the mode of fixing the signal transmission line on the outer circumferential surface of the main shaft 100 by pressing the tablet 610 and the flat position 110. It can be understood that the thickness of the tablet 610 is thinner than the thickness of the flat position 110, and the width of the tablet 610 is also smaller than the width of the flat position 110. The tablet 610 is fixed on the stator 210 by screws, so that the position of the tablet 610 relative to the flat position 110 can be determined. Thus, the position of the signal transmission line on the flat position 110 and the position of the signal transmission line on the side of the stator 210 after passing through the flat position 110 are simultaneously limited.

[0075] In the above embodiment, the tablet 610 can be a thin metal sheet, such as a steel sheet or a copper sheet, etc.

[0076] As can be seen from Figure 5 , the main shaft 100 is provided with three shaft shoulders. Taking the perspective in Figure 5 as the reference, the left shaft shoulder is used for positioning the second bearing 12, the middle second shaft shoulder is used for blocking the axial movement of a wire pressing ring for pressing the signal transmission line on the torque sensor 600 at this position to avoid interference with the second sun gear 321. The right third shaft shoulder is used for positioning the installation position of the main shaft 100 on the assisted bicycle to prevent the axial movement of the main shaft 100.

[0077] Referring to Figure 6 , Figure 6 , an exploded view of the hub motor is shown. The assembly sequence of the hub motor in the present application is as follows: taking Figure 2The first step is to set the torque sensor 600 on the main shaft 100 from the right side, and position it through the shaft shoulder on the main shaft 100. The signal transmission line is placed along the flat position 110. The front end of the signal transmission line is an FPC ultra-thin end. The end is small in size, which can allow other parts to be fitted into the main shaft 100. If a larger end is used, the end can be lowered to one side of the main shaft 100 first, and then the end is connected to the motor 200 after the other parts are fitted. The second step is to fit the end cover 15 from the right side, and press the left part of the torque sensor 600 to fix it. Then the second planetary gear train is fitted from the left side, and the second planetary carrier 323 is fixed to the end cover 15. The second planetary carrier 323 can be pre-installed with a bearing between the main shaft 100, or it can not be installed.

[0078] The fourth step is to install the wear-resistant sheet 530 and the one-way bearing 500 from the left side. The wear-resistant sheet 530 is placed in the groove on the end face of the second planetary carrier 323. The one-way bearing 500 is installed in the second ring 3212 of the second planetary carrier 323. Figure 3 As can be seen from the structure of the second sun gear 321, the second sun gear 321 is provided with three rings. The second ring 3212 away from the main shaft 100 is used to bear the one-way bearing 500, and the inner ring 510 is tightly fitted with the second ring 3212 of the second sun gear 321. The outer ring 520 is attached to the third ring 3213. When installing the one-way bearing 500, the wear-resistant sheet 530 is placed in the groove on the end face of the second planetary carrier 321. The ring close to the main shaft 100 is used to press the second bearing 12.

[0079] The fifth step is to install the first planetary carrier 313, and fix the first planetary carrier 313 and the outer ring 520 of the single bearing through bolts. The sixth step is to install a plurality of first planetary gears 312, and the installation method is to set the first planetary gears 312 on the rotating part of the first planetary carrier 313 extending from the end face. The seventh step is to install the gland 314, which is rotationally connected with the rotating part of the first planetary carrier 313. When the first planetary carrier 313 rotates, the gland 314 and the first planetary carrier 313 rotate together. The first planetary gears 312 are located between them for rotation and revolution.

[0080] The seventh step is to install the first bearing 11 in the area between the gland 314 and the main shaft 100. The eighth step is to install the first sun gear 311 and the inner ring 310, which can be installed to the preset position by rotating the first planetary gears 312. The ninth step is to install the motor 200, which includes a rotor 220. The rotor 220 and the first sun gear 311 are thermally assembled, and the first bearing 11 is located in the intermediate area between the rotor 220 and the gland 314 in the radial direction. In this way, the gland 314 and the rotor 220 are rotationally connected. From Figure 1The structure of the rotor 220 can be seen, which is provided with a horizontal ring bearing the third bearing 13. A stop 223 is arranged at the horizontal ring end of the rotor 220 for limiting the position of the third bearing 13. A magnetic steel 224 is arranged at the outer side strut gap of the rotor 220, and a steel ring 225 is arranged outside the magnetic steel 224 for protection, and the steel ring 225 is fixedly connected with the rotor 220. The stator 210 comprises a stator bracket 211 and a winding 212 arranged on the stator bracket 211, and the stator 210 is connected with the inner ring gear 310 through bolts. A receiving space is arranged in the middle of the stator 210 for mounting a controller, and then a signal transmission line is connected with the controller.

[0081] The tenth step is to mount the fourth bearing 14 on the base. The eleventh step is to mount the hub shell 400 on the fourth bearing 14, and then bolt the right side to the end cover 15.

[0082] The hub motor operates as follows: the torque sensor 600 is divided into an internal fixed component and an external rotating component. The rotating component rotates with the user's foot pedal, and the fixed component extends a signal transmission line. The main shaft 100, the stator 210, the inner ring gear 310 and the signal transmission line are in a fixed state, the rotor 220 rotates to drive the primary planetary gear train, drives the secondary planetary gear train through the one-way bearing 500, and finally the output member is the secondary planet carrier 323, which drives the end cover 15 and the hub shell 400 to rotate, thereby driving the wheel to rotate.

[0083] In the hub motor mentioned in the above embodiment, the motor can be freely selected according to the assembly requirements. The structure of the rotor 220 can be more compact with the structure of the primary sun gear 311, and space is left for the gland 314 to avoid rotation interference between the rotor 220 and the primary planet carrier 313. In other embodiments, the structure of the rotor 220 can be determined according to actual requirements and assembly.

[0084] The application also provides a power-assisted bicycle, which comprises a driving wheel, mainly a rear wheel. The hub motor is located at the center of the rear wheel. The main shaft 100 in the hub motor is a hollow shaft, which is sleeved on the central shaft of the rear wheel of the power-assisted bicycle. The driving wheel comprises a plurality of spokes, the hub shell 400 in the hub motor is connected with the plurality of spokes, and the main shaft 100 in the hub motor is fixedly connected with the central shaft of the driving wheel.

[0085] The above only describes the preferred embodiments of the present application and is not intended to limit the present application. Any modification, equivalent replacement and improvement made within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. A wheel hub motor for use on a drive wheel of a power assisted bicycle, characterised in that, The application relates to a main shaft (100), a motor (200) including a stator (210) and a rotor (220), the stator (210) being fixedly connected with the main shaft (100), the stator (210) driving the rotor (220) to rotate, a double-planetary reducer including a primary planetary gear train, a secondary planetary gear train and an inner gear ring (310), the inner gear ring (310) being fixedly connected with the stator (210), the planetary gears in the primary planetary gear train and the secondary planetary gear train being in mesh with the inner gear ring (310), the rotor (220) driving the primary planetary gear train to rotate, the primary planetary gear train and the secondary planetary gear train being in one-way clutch transmission connection, a hub shell (400) being rotationally connected with the main shaft (100) and fixedly connected with an output member in the secondary planetary gear train, the hub shell (400) being used for externally connecting spokes of the driving wheel. The primary planetary gear train includes a primary sun gear (311), a primary planetary gear (312) and a primary planet carrier (313), the primary sun gear (311) being fixedly connected with the rotor (220), the primary planetary gear (312) being mounted on the primary planet carrier (313), the primary planet carrier (313) being rotationally connected with the main shaft (100), the primary planetary gear (312) being in mesh with the primary sun gear (311), the rotor (220) driving the primary sun gear (311) to rotate, the primary sun gear (311) driving the primary planet carrier (313) to run at a reduced speed through the primary planetary gear (312), so that primary speed reduction is realized. The secondary planetary gear train includes a secondary sun gear (321), a secondary planetary gear (322) and a secondary planet carrier (323), the secondary sun gear (321) being rotationally connected with the main shaft (100) and in one-way clutch transmission connection with the primary planet carrier (313), the secondary sun gear (321) being in mesh with the secondary planetary gear (322), the secondary planetary gear (322) being mounted on the secondary planet carrier (323), the secondary planet carrier (323) being rotationally connected with the main shaft (100), the secondary planetary gear (322) being in mesh with the secondary sun gear (321). The primary planet carrier (313) drives the secondary sun gear (321) to rotate, the secondary sun gear (321) driving the secondary planet carrier (323) to run at a reduced speed through the secondary planetary gear (322), so that secondary speed reduction is realized. The stator (210) includes a base being sleeved on and fixed to the outer side of the main shaft (100) and a stator bracket (211) being arranged on the outer circumferential surface of the base, the stator bracket (211) being provided with a winding (212), the base being provided with a displacement cavity.

2. The wheel hub motor according to claim 1, characterized in that ​ ​ ​ 3. The wheel hub motor according to claim 2, characterized in that ​ The rotor (220) comprises a rotating part (221), a first connecting part (222) and a magnetic steel (224), wherein the rotating part (221) is sleeved on the main shaft (100) and located in the accommodation cavity, a third bearing (13) is arranged between the rotating part (221) and the inner wall of the accommodation cavity, and the rotor (220) rotates relative to the stator (210) through the third bearing (13); a stop part (223) is arranged at one end of the rotating part (221) close to the base along the axial direction of the main shaft (100), the first connecting part (222) extends radially outward from the outer wall of the rotating part (221), and the magnetic steel (224) is fixed to the first connecting part (222) and surrounds the outside of the winding (212).

4. The wheel hub motor of claim 2, wherein The primary planetary carrier (313) and the secondary sun gear (321) are drivingly connected through a one-way bearing (500), the one-way bearing (500) comprises an inner ring (510) and an outer ring (520), one of the inner ring (510) and the outer ring (520) is fixedly connected with the primary planetary carrier (313), and the other is fixedly connected with the secondary sun gear (321), so that the secondary sun gear (321) is configured to be able to rotate independently of the primary planetary carrier (313).

5. The wheel hub motor according to claim 4, characterized in that The secondary sun gear (321) is coaxially provided with a first ring (3211), a second ring (3212) and a third ring (3213) spaced from inside to outside on one side close to the primary planetary carrier (313); The first ring (3211) and the main shaft (100) are spaced to accommodate a second bearing (12), the secondary sun gear (321) is drivingly connected with the main shaft (100) through the second bearing (12), the second ring (3212) is used for bearing the inner ring (510) of the one-way bearing (500) away from the main shaft (100), so as to realize that the one-way bearing (500) drives the secondary sun gear (321) to rotate, and the third ring (3213) is attached to the outer ring (520), so as to limit the axial displacement of the outer ring (520).

6. The wheel motor according to claim 4, characterized by The one-way bearing (500) further comprises two wear-resistant sheets (530), and the two wear-resistant sheets (530) are respectively located on both sides of the rollers of the one-way bearing (500), one of the wear-resistant sheets (530) is close to the primary planetary carrier (313), and the other is close to the secondary sun gear (321).

7. The in-wheel motor according to claim 1, characterized by The primary planetary gear train further comprises a gland (314), the gland (314) is fixedly connected with the primary planetary carrier (313), and the primary planetary gear (312) is located between the gland (314) and the planetary carrier. The gland (314) and the primary sun gear (311) are drivingly connected through a first bearing, and the gland (314) is provided with a limiting portion, the limiting portion is attached to one side of the first bearing close to the primary planetary gear (312), so as to limit the position of the first bearing and the primary sun gear (311).

8. The in-wheel motor according to claim 1, characterized by Also include torque sensor (600), the motor (200) is provided with a controller, the torque sensor (600) is connected with the controller, the torque sensor (600) is used to be connected with the pedal drive, to perceive the size of external pedaling force and generate corresponding electrical signal, the controller can accept the electrical signal adjusts the output torque of the motor (200).

9. A wheel hub motor for use on a drive wheel of a power assisted bicycle, characterised in that, Include: Main shaft (100), the outer peripheral surface is provided with flat position (110) extending along its length direction; Planetary reducer, sleeve set on the main shaft (100) and rotatably connected with the main shaft (100); Hub shell (400), rotatably connected with the main shaft (100), the hub shell (400) is used to circumscribe the spoke of the drive wheel, the output part in the planetary reducer is fixedly connected with the hub shell (400); Motor (200), including stator (210) and rotor (220), the stator (210) is fixedly connected with the main shaft (100), the stator (210) drives the rotor (220) to rotate, the rotor (220) is fixedly connected with the input part in the planetary reducer, to drive the hub shell (400) to rotate through the planetary reducer; Torque sensor (600), including body and signal transmission line, the signal transmission line is connected with the body, along the main shaft (100) axis direction, the body, the planetary reducer and the motor (200) are sequentially arranged along the length extension direction of the main shaft (100), the body is used to perceive the size of external pedaling force and generate corresponding electrical signal, the signal transmission line passes through the flat position (110) and is electrically connected with the motor (200), to adjust the rotating speed of the rotor (220).

10. The wheel hub motor of claim 9, wherein, Also include pressing sheet (610), the width of the pressing sheet (610) is less than the width of the flat position (110), the pressing sheet (610) is fixedly connected with the flat position (110) and is provided with a channel for the flexible cable to pass through.

11. The wheel hub motor of claim 9, wherein, The planetary reducer is a double planetary reducer, the double planetary reducer includes a primary planetary gear train and a secondary planetary gear train, the primary planetary gear train and the secondary planetary gear train are connected by one-way bearing (500) to realize one-way clutch transmission.

12. A power assisted bicycle characterised in that, Include the hub motor as claimed in any one of claims 1-11, also include drive wheel, the hub motor is located at the center position of the drive wheel, the drive wheel includes a plurality of spokes, the hub shell (400) in the hub motor is connected with a plurality of spokes, the main shaft (100) in the hub motor is fixedly connected with the central shaft of the drive wheel.

Images