CN218124495U - Hub motor and power-assisted electric bicycle - Google Patents

Abstract

The utility model discloses a hub motor and a power-assisted electric bicycle, wherein the hub motor comprises a shell, a main shaft, a motor part, a composite planet wheel unit and a one-way clutch, and the motor part comprises a stator and a rotor; the compound planet wheel unit comprises a primary planet speed reducing system and a secondary planet speed reducing system, wherein the primary planet speed reducing system comprises a first sun wheel and a first planet carrier, and the first sun wheel is connected with a rotor; the secondary planetary reduction system comprises a second sun gear, a second gear ring and a second planet carrier, the second sun gear is fixedly connected to the first planet carrier, and the second gear ring is fixed on the machine shell; the second planet carrier is connected with the main shaft through a one-way clutch. The composite planet wheel unit adopts two-stage speed reduction, the speed reduction ratio is obviously increased, the assembly process is simple, and the reliability is high. In addition, the second planet carrier is connected with the main shaft through the one-way clutch, so that when the power-assisted electric bicycle slides, the wheels can be separated from the motor part, and the wheels are prevented from driving the motor to rotate.

Description

Hub motor and power-assisted electric bicycle

Technical Field

The utility model relates to a helping hand electric bicycle technical field, in particular to in-wheel motor and helping hand electric bicycle.

Background

In the related art, a hub motor of a power-assisted electric bicycle is composed of a motor, a motor shaft and a shell and used for driving the electric bicycle to move forward. The hub motor is often mounted on a front wheel or a rear wheel of the electric bicycle. Most in-wheel motors are directly driven by a motor rotor to move forward, the motors need to provide large torque when a bicycle is started and a large load is carried out, and the large torque of the motors means large volume, heavy weight and high cost. In order to increase the reduction ratio, the hub motor also has a reduction gear disposed inside the hub motor, such as an outer rotor toothed hub motor and an inner rotor toothed hub motor adopting a scheme that a main shaft is a broken shaft. However, in the related art, the external rotor toothed hub motor needs to greatly increase the volume of the speed reducer to improve the speed reduction ratio, which is contrary to the miniaturization of the hub motor. The inner rotor toothed hub motor with the main shaft adopting the broken shaft scheme has the advantages of more structural parts, complex assembly process, low product total cost plus production cost and weak structural strength. In addition, when the bicycle slides, the motor does not work, and the wheels move forwards, so that the wheels drive the motor to rotate. Because the motor has a cogging torque, the cogging torque is increased after the speed of the speed reducer is changed, and the wheel resistance is increased. Also, the back emf of the motor can affect the controller.

SUMMERY OF THE UTILITY MODEL

The utility model discloses aim at solving one of the technical problem that exists among the prior art at least. Therefore, the utility model provides a wheel hub motor can increase the reduction ratio, and assembly process is simple, and the reliability is high to can prevent that the wheel from driving the motor and rotating when helping hand electric bicycle slides.

The utility model discloses still provide a helping hand electric bicycle who has above-mentioned in-wheel motor.

According to the embodiment of the first aspect of the utility model, the hub motor comprises a casing, a main shaft, a motor part, a compound planet wheel unit and a one-way clutch, wherein the main shaft penetrates through the casing and can rotate relative to the casing; the motor part is arranged on the main shaft and comprises a stator and a rotor, the stator is fixedly connected with the main shaft, and the rotor and the main shaft are coaxially arranged and can rotate relatively; the compound planetary gear unit comprises a primary planetary reduction system and a secondary planetary reduction system, the primary planetary reduction system comprises a first sun gear, a first gear ring, a first planetary gear and a first planet carrier, the first sun gear is connected with the rotor, the first gear ring is fixed on the casing, and the first planetary gear is respectively meshed with the first sun gear and the first gear ring; the secondary planetary reduction system comprises a second sun gear, a second gear ring, a second planetary gear and a second planetary carrier, the second sun gear is fixedly connected to the first planetary carrier, the second gear ring is fixed on the machine shell, and the second planetary gear is respectively meshed with the second sun gear and the second gear ring; the second planet carrier is connected with the main shaft through the one-way clutch.

According to the utility model discloses in-wheel motor has following beneficial effect at least: the composite planet wheel unit adopts two-stage speed reduction, the speed reduction ratio is the product of the first-stage speed reduction ratio and the second-stage speed reduction ratio, the speed reduction ratio is obviously increased, the assembly process is simple, and the reliability is high. In addition, the second planet carrier is connected with the main shaft through the one-way clutch, so that when the power-assisted electric bicycle slides, wheels can be separated from the motor part, and the wheels are prevented from driving the motor to rotate.

According to some embodiments of the present invention, the housing comprises a housing and an end cover, the housing is connected to the end cover to form a cavity, the motor portion the compound planetary gear unit and the one-way clutch are located in the cavity.

According to some embodiments of the invention, the housing and the end cap are bonded, interference connected or screwed together.

According to some embodiments of the present invention, the motor portion is an inner rotor motor, an outer rotor motor, or a disc motor structure.

According to some embodiments of the invention, the one-way clutch is of a sprag, roller or ratchet type construction.

According to some embodiments of the utility model, one way clutch includes mounting and moving part, mounting fixed connection in the main shaft, the moving part with the second planet carrier is integrative, or the moving part with the second planet carrier bonds, interference connection or passes through bolted connection.

According to some embodiments of the invention, the first sun gear with the rotor is an organic whole, or the first sun gear with the rotor plastic-covered molding, bonding, interference connection or through screw connection.

According to some embodiments of the invention, the second sun gear is integral with the first planet carrier, or the second sun gear is bonded, interference connected or screwed to the first planet carrier.

According to some embodiments of the invention, the first gear ring and the second gear ring are of unitary construction or are connected by splines.

According to some embodiments of the invention, the first ring gear and at least one of the second ring gears, with the casing bond, interference connection, through spline connection or through screw connection.

According to some embodiments of the invention, the motor part comprises a support, the stator is connected to the support, the support with the main shaft bonds, welds, interference connects, through flat key, spline or screw connection.

According to the utility model discloses a helping hand electric bicycle of second aspect embodiment, include the utility model discloses an in-wheel motor of first aspect embodiment.

According to the utility model discloses helping hand electric bicycle has following beneficial effect at least: through adopting the utility model discloses a wheel hub motor of first aspect embodiment can increase the reduction ratio, and assembly process is simple, and the reliability is high to can prevent that the wheel from driving the motor and rotating when helping hand electric bicycle slides.

Additional aspects and advantages of the invention will be set forth in part in the description which follows and, in part, will be obvious from the description, or may be learned by practice of the invention.

Drawings

The invention will be further described with reference to the following drawings and examples, in which:

fig. 1 is a cross-sectional view of an in-wheel motor according to an embodiment of the present invention;

FIG. 2 is an exploded view of one direction of the in-wheel motor shown in FIG. 1;

FIG. 3 is an exploded view of the hub motor shown in FIG. 1 in another orientation;

fig. 4 is a schematic view of the bracket and spindle shown in fig. 3.

Reference numerals:

101. a housing; 102. a main shaft; 103. a motor section; 104. a one-way clutch; 105. a housing; 106. an end cap; 107. a first bearing; 108. a second bearing; 109. a stator; 110. a rotor; 111. a third bearing; 112. a first sun gear; 113. a first ring gear; 114. a first planet gear; 115. a first carrier; 116. a second sun gear; 117. a second ring gear; 118. a second planet wheel; 119. a second planet carrier; 120. a fixing member; 121. a movable member;

201. a support; 202. a shaft shoulder;

401. a threaded hole; 402. connecting holes; 403. a connecting portion.

Detailed Description

Reference will now be made in detail to embodiments of the present invention, examples of which are illustrated in the accompanying drawings, wherein like reference numerals refer to the same or similar elements or elements having the same or similar function throughout. The embodiments described below with reference to the accompanying drawings are exemplary only for explaining the present invention, and should not be construed as limiting the present invention.

In the description of the present invention, it should be understood that the orientation or positional relationship indicated with respect to the orientation description, such as up, down, front, rear, left, right, etc., is based on the orientation or positional relationship shown in the drawings, and is only for convenience of description and simplification of description, and does not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and thus, should not be construed as limiting the present invention.

In the description of the present invention, a plurality of meanings are one or more, a plurality of meanings are two or more, and the terms greater than, smaller than, exceeding, etc. are understood as excluding the number, and the terms greater than, lower than, within, etc. are understood as including the number. If the first and second are described for the purpose of distinguishing technical features, they are not to be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated or implicitly indicating the precedence of the technical features indicated.

In the description of the present invention, unless there is an explicit limitation, the words such as setting, installation, connection, etc. should be understood in a broad sense, and those skilled in the art can reasonably determine the specific meanings of the above words in combination with the specific contents of the technical solution.

The power-assisted electric bicycle has been developed for twenty years from the first product to the present, and has now formed a huge industry. The electric bicycle is not only used as a travel tool, but also as a sport tool, and is deeply favored by the majority of riding enthusiasts.

The booster electric bicycle is a new type two-wheel vehicle, belonging to a kind of bicycle, and uses battery as auxiliary power source, and is equipped with motor, and possesses power auxiliary system, and can implement manpower riding and motor boosting integrated new type transportation means.

In the field of power-assisted electric bicycles, the installation positions of motors are mainly divided into two types, one type is a middle-mounted motor, namely, the motor is installed in the middle position of a bicycle body, namely, the motor in a five-way position, and the middle-mounted motor is called as a middle-mounted motor. Put motor and connected to vehicle frame in to be connected and transmit power through chain and rear wheel, pedal is installed to the both sides of motor simultaneously, and under the condition that the motor does not have the power, the personnel of riding can realize through pedal that the manpower rides, and resistance and normal bicycle do not have the difference.

Another type is mounted in the hub of a bicycle, called a hub motor. The hub motor is integrated inside the hub as the name implies, and after the hub motor is electrified, the motor converts electric energy into mechanical energy, so that the wheel is driven to rotate, and the vehicle is driven to move forward. The in-wheel motor is usually mounted on either the front or rear wheel.

The hub motor driving system of the power-assisted electric bicycle has a certain market in the electric bicycle industry due to price advantage and simple modification.

Because simple structure, it is convenient to maintain, noise low grade advantage, what earliest helping hand electric bicycle wheel hub motor adopted is mostly directly driving the scheme.

With the development of technology and materials, the noise of a transmission system is greatly reduced by adopting the plastic gear. Although the hub motor with the speed reducer has slightly larger noise than a direct-drive hub motor, the hub motor with the speed reducer has the advantages of small size, light weight, large torque force of the hub motor and the like, and particularly, the hub motor with the speed reducer has great advantages in cost because the using amount of the magnetic material is small along with the great increase of the price of the magnetic material. The reduction ratio is improved, and the motor part and the hub motor are smaller and lighter, so that the main idea and the direction for the development of the hub motor of the power-assisted electric bicycle are provided.

The motor part of the geared hub motor has two types, namely an inner rotor and an outer rotor, and the speed reduction device of the hub motor is taken as a planetary gear speed reduction system as an example for explanation.

The stator of the external rotor geared hub motor in the market is fixed on a main shaft, a sun gear is installed on a rotor, a planet carrier is fixed on the main shaft, and the power of the motor part is reduced by a planetary gear reduction system and is output to a shell by a gear ring. In the planetary gear reduction system, a sun gear is input, a planet carrier is fixed, and a ring gear is output. Therefore, the reduction ratio of the planetary gear reduction system is the ratio of the number of teeth of the ring gear to the number of teeth of the sun gear, and the number of teeth of the sun gear as the denominator has a large influence on the reduction ratio. Because the main shaft on the structure of the external rotor toothed hub motor penetrates through the center of the sun gear, the diameter of the sun gear is larger, the diameter of the gear ring needs to be greatly increased when the reduction ratio is required to be improved, and the reduction ratio is contrary to the miniaturization of the hub motor. The reduction ratio of the 250W motor is usually 4.42 for the products available on the market. And the reduction ratio of a product partially adopting a duplex planetary gear structure does not exceed 8.

The inner rotor on the market takes tooth wheel hub motor, does the sun gear for promoting the reduction ratio for a short time, simultaneously because structural permission, the main shaft has adopted disconnected axle scheme, and the main shaft divide into left end axle and right end axle promptly. The fixed part of the inner rotor toothed hub motor assembly sequentially comprises a left end shaft, a motor machine shell, a planet carrier and a right end shaft. The stator and rotor of the motor are both in the motor casing, and the power is transmitted to the casing via the planetary gear speed reducing system and the sun gear driven by the rotor. Compared with an outer rotor toothed hub motor, the inner rotor toothed hub motor has the advantages that the diameter of a sun gear is smaller, if a planet wheel adopts a duplex structure, the reduction ratio is greatly improved, the reduction ratio of the 250W inner rotor toothed hub motor on the market can be about 12 generally, and the theoretical maximum reduction ratio can be 15. Although the material cost of the inner rotor scheme is lower than that of the outer rotor scheme, the inner rotor scheme has more structural parts and complex assembly process, and the total product cost plus the production cost has no great advantages. Meanwhile, the inner rotor scheme adopts a broken shaft structure, so that the structural strength is weaker than that of the outer rotor scheme, and the assembly precision of the assembly is difficult to ensure, so that the product reliability is always inferior to that of the outer rotor scheme, and the use number of the inner rotor toothed hub motor in the market is always lower than that of the outer rotor toothed hub motor.

The following describes an in-wheel motor according to an embodiment of the present invention with reference to fig. 1 to 4.

Referring to fig. 1, an in-wheel motor according to an embodiment of the present invention includes a housing 101, a main shaft 102, a motor unit 103, a composite planetary gear unit, and a one-way clutch 104. A cavity is formed in the housing 101, and the motor part 103, the compound planetary gear unit, and the one-way clutch 104 are located in the cavity.

Referring to fig. 1 to 3, it can be understood that the casing 101 includes a casing 105 and an end cover 106, and the casing 105 and the end cover 106 are fixedly connected to form a cavity to enclose the motor part 103, the one-way clutch 104 and the compound planetary gear unit inside. In this example, the housing 105 and the end cover 106 are both mounted on the main shaft 102 through bearings, and the housing 105 and the end cover 106 are connected through screws. It will be appreciated that other fastening means such as adhesive, interference fit, etc. may be used to secure the housing 105 to the end cap 106.

The main shaft 102 serves as a fixture 120, and the main shaft 102 penetrates the entire housing 101 and is rotatable relative to the housing 101. That is, the housing 101 is coaxially mounted with the main shaft 102 and is freely rotatable. Specifically, the main shaft 102 is provided with a first bearing 107 and a second bearing 108, the first bearing 107 and the second bearing 108 correspond to two ends of the casing 101 along the axial direction of the main shaft 102, the casing 101 is provided on the first bearing 107 and the second bearing 108, that is, the end cover 106 is provided on the first bearing 107, and the housing 105 is provided on the second bearing 108. In other words, the housing 101 and the main shaft 102 are rotatably connected through the first bearing 107 and the second bearing 108.

The motor part 103 is mounted on the main shaft 102 and is used for providing power for a hub motor of the power-assisted electric bicycle. The motor part 103 comprises a stator 109 and a rotor 110, the stator 109 is fixedly connected with the main shaft 102 and can not rotate relatively, and the rotor 110 is rotatably connected with the main shaft 102. Specifically, the stator 109 may be in interference connection with the main shaft 102, such that the shaft hole diameter of the stator 109 is slightly smaller than the outer diameter of the main shaft 102. Of course, the stator 109 may also be fixed to the main shaft 102 by other means, such as bonding, welding or by screwing, by spline connection, or by key connection.

Referring to fig. 2 to 4, it can be understood that the motor part 103 of the present embodiment further includes a bracket 201, a shoulder 202 is disposed on the main shaft 102, a threaded hole 401 is disposed on the shoulder 202, and an axial direction of the threaded hole 401 is parallel to an axial direction of the main shaft 102. The bracket 201 is provided with a connecting part 403, the connecting part 403 is provided with a connecting hole 402, the position of the connecting hole 402 corresponds to the position of the threaded hole 401, and the diameter of the connecting hole 402 is slightly larger than that of the threaded hole 401, or the diameter of the connecting hole 402 is equal to that of the threaded hole 401. The stator 109 is pressed on the bracket 201 in an interference fit manner, and then the bracket 201 is fixed on the main shaft 102 through a screw connection, that is, the screw passes through the connecting hole 402 and then is connected to the threaded hole 401, and the bracket 201 is fixed on the shaft shoulder 202, so that the stator 109 and the main shaft 102 are fixedly connected.

Referring to fig. 1 to 3, it can be understood that the main shaft 102 is further provided with a third bearing 111, the third bearing 111 is located between the first bearing 107 and the second bearing 108, and the rotor 110 is arranged on the third bearing 111, i.e. the rotor 110 is rotatably connected with the main shaft 102 through the third bearing 111. It is understood that the rotor 110 may also be mounted on the inner wall of the casing 101, and the function of the rotor 110 being coaxially arranged with the main shaft 102 and capable of rotating relatively can also be realized.

Referring to fig. 1, it can be understood that the motor part 103 of the present example adopts an outer rotor motor structure, i.e., the rotor 110 is located outside the stator 109 in the radial direction of the main shaft 102. It should be noted that the motor portion 103 of the present example may also adopt an inner rotor motor structure or a disc motor structure. The inner rotor motor structure means that the rotor 110 is located inside the stator 109 in the radial direction of the main shaft 102. The disc motor structure, also called axial motor structure or disc motor structure, generally the stator 109 and the rotor 110 are both in a disc structure, the stator 109 is on a flat substrate, the rotor 110 is covered on the stator 109, generally the stator 109 is a coil, and the rotor 110 is a permanent magnet or a disc adhered with a permanent magnet.

Referring to fig. 1 to 3, it can be understood that the compound planetary gear unit is installed coaxially with the main shaft 102, and power is input by the motor part 103, and is output to the housing 101 after being decelerated by the compound planetary gear unit.

Specifically, the compound planetary gear unit comprises a primary planetary reduction system and a secondary planetary reduction system, the primary planetary reduction system comprises a first sun gear 112, a first gear ring 113, a first planetary gear 114 and a first planet carrier 115, the first sun gear 112 is connected with the rotor 110, the first gear ring 113 is fixed on the casing 101, and the first planetary gear 114 is respectively meshed with the first sun gear 112 and the first gear ring 113. In other words, the first sun gear 112 is disposed coaxially with the main shaft 102 and is fixedly mounted on the rotor 110. The first carrier 115 is disposed coaxially with the main shaft 102 and is freely rotatable. The first planetary gears 114 are mounted on a first planetary gear shaft of the first carrier 115 while being engaged with the first sun gear 112 and the first ring gear 113. The first ring gear 113 is an inner ring gear, is coaxial with the main shaft 102, and is fixedly connected with the casing 101.

The secondary planetary reduction system comprises a second sun gear 116, a second gear ring 117, a second planet gear 118 and a second planet carrier 119, the second sun gear 116 is fixedly connected to the first planet carrier 115, the second gear ring 117 is fixed to the machine shell 101, and the second planet gear 118 is respectively meshed with the second sun gear 116 and the second gear ring 117; the second carrier 119 is connected to the main shaft 102 via the one-way clutch 104. The second sun gear 116 is coaxial with the main shaft 102 and is fixedly mounted on the first carrier 115 so as to rotate with the first carrier 115. The second planetary carrier 119 is coaxial with the main shaft 102, and the second planetary gear 118 is mounted on a second planetary gear shaft of the second planetary carrier 119 while meshing with the second sun gear 116 and the second ring gear 117. The second ring gear 117 is an annular gear, and is coaxial with the main shaft 102 and fixedly connected with the casing 101.

The first sun gear 112 is rotatably disposed on the main shaft 102, and the first sun gear 112 is used as an input end and connected to an output end of the motor portion 103, that is, the first sun gear 112 is connected to the rotor 110, so that the motor portion 103 can drive the first sun gear 112 to rotate. The rotor 110 is fixedly connected with the first sun gear 112, one embodiment of the connection is screw connection, and another embodiment of the connection is that the first sun gear 112 and the rotor 110 are molded in an encapsulating mode, and the structure mode of the molding in the encapsulating mode can reduce the number of parts, so that the cost is reduced, and the axial size is reduced. Of course, other schemes such as bonding, interference, and making a single piece may be used to fix the first sun gear 112 to the rotor 110.

The first sun gear 112 is engaged with the first planetary gear 114, the first planetary gear 114 is engaged with the first ring gear 113, the first ring gear 113 is fixedly connected with the casing 101, and the first carrier 115 is connected with an input end of the secondary planetary reduction system, so that power can be transmitted to the secondary planetary reduction system through the first carrier 115. The number of the first planetary gears 114 may be 3, 4, or 5, and the plurality of first planetary gears 114 are arranged in one turn around the center of the first sun gear 112.

It will be appreciated that the second sun gear 116, which serves as the input of the two-stage planetary reduction system, is fixedly connected to the first planet carrier 115 such that the first planet carrier 115 can rotate the second sun gear 116. For example, the second sun gear 116 and the first planet carrier 115 are fixedly connected by means of bolts, splines, interference connections, bonding, etc., and may even be directly processed into a whole. The number of the second planetary gears 118 may be 3, 4 or 5, and a plurality of the second planetary gears 118 are arranged in one circle with the center of the second sun gear 116 as an axis.

When the motor part 103 operates, the second sun gear 116 can sequentially drive the second planet gear 118 and the second ring gear 117 to rotate, and further drive the casing 101 to rotate through the second ring gear 117. The first ring gear 113 and the second ring gear 117 may be integrated as a whole, or may be fixedly connected by a spline, that is, the first ring gear 113 and the second ring gear 117 are connected to the casing 101 together as an output structure to transmit power to the casing 101. The first ring gear 113 and the second ring gear 117 may be different or the same.

The first ring gear 113 and the second ring gear 117 are connected to the housing 101, and the first ring gear 113 and the second ring gear 117 are directly connected to the housing 101, or indirectly connected to the housing 101 through an intermediate member, as long as power can be transmitted to the housing 101 to be output. For example, the first ring gear 113 and the housing 101 may be bonded, interference-connected, or connected by spline connection, screw connection. The second ring gear 117 and the casing 101 may be bonded, interference-bonded, or connected by spline connection, screw connection.

It should be noted that, the above is only exemplified by taking the compound planetary gear unit as the two-stage planetary reduction mechanism, and the compound planetary gear unit may also be a three-stage or more planetary reduction mechanism.

Referring to fig. 1 to 3, it can be understood that the one-way clutch 104 is installed between the second carrier 119 and the main shaft 102, and the one-way clutch 104 is installed coaxially with the main shaft 102 and allows only one-way transmission of the motor part 103 with respect to the main shaft 102. For example, when the motor 103 is driven in the forward direction, the one-way clutch 104 is engaged to provide a support for the second planet carrier 119, so that the motor 103 drives the casing 101 to rotate, and the power-assisted electric bicycle realizes a forward motion. When the motor part 103 is driven in the reverse direction, the one-way clutch 104 is in a disengaged state, and the power of the motor part 103 cannot be transmitted to the casing 101 through the second planet carrier 119, so that the interference of the motor part 103 to the casing 101 is avoided.

More specifically, the one-way clutch 104 includes a fixed element 120 and a movable element 121, and a clutch structure is disposed between the fixed element 120 and the movable element 121, so that the movable element 121 rotates away from the fixed element 120 when rotating in a forward direction, and the movable element 121 is fixed to the fixed element 120 when rotating in a reverse direction. The fixed member 120 is used as an inner ring of the one-way clutch 104 and fixedly connected to the main shaft 102, and the movable member 121 is used as an outer ring of the one-way clutch 104 and is integrated with the second planet carrier 119, or the movable member 121 and the second planet carrier 119 are bonded, connected in an interference manner or connected through screws.

The one-way clutch 104 of this embodiment is a roller clutch structure, the fixed part 120 of the one-way clutch 104 is fixed on the main shaft 102 through a spline, and the movable part 121 and the fixed part 120 of the clutch can only realize one-way rotation, so that the movable part 121 can only rotate in one way relative to the main shaft 102. It is understood that the one-way clutch 104 may also be of a ratchet one-way clutch 104, sprag one-way clutch 104 configuration.

The utility model discloses in-wheel motor during operation, motor portion 103 corotation drives first sun gear 112 rotatory. At this time, the one-way clutch 104 is in a combined state, the power transmission state of the compound planetary gear unit is that the first sun gear 112 is input, the second planet carrier 119 is fixed, the first gear ring 113 and the second gear ring 117 form an integrated member for output, and the second gear ring 117 drives the casing 101 to rotate to output power.

When the forward rotation speed of the casing 101 is greater than the rotation speed of the motor part 103 after being decelerated by the compound planetary gear unit, for example, when the bicycle slides, rides without power, and the manpower riding speed exceeds the output speed of the motor part 103, the casing 101 drives the first gear ring 113 and the second gear ring 117 to synchronously rotate, which is equivalent to the reverse rotation of the motor part 103, and the one-way clutch 104 is disengaged.

Cogging torque exists between the rotor 110 and the stator 109, when the internal resistance of the composite planetary gear unit is smaller than the cogging torque, the composite planetary gear unit can be regarded as fixed as the first sun gear 112, and the composite planetary gear unit only overcomes the rotation resistance after the one-way clutch 104 is disengaged to rotate in an idle load mode. When the internal resistance of the composite planetary gear unit is greater than the cogging torque, the composite planetary gear unit drives the sun gear to integrally and synchronously rotate, and the composite planetary gear unit can be regarded as that the second gear ring 117 directly overcomes the cogging torque and the rotation resistance after the one-way clutch 104 is disengaged to rotate. The power from the casing 101 to the rotor 110 has no process of speed change and torque change.

When the bicycle slides, the motor part 103 does not run, and the wheels move forwards. If the one-way clutch 104 is not provided, the wheels can drive the rotor 110 to rotate, and two results are obtained, namely, the cogging torque is generated in the motor part 103, and if the one-way clutch 104 is not provided, the torque is increased after the cogging torque is subjected to speed change through the compound planetary gear unit, and the wheel resistance is increased. Another is that if the one-way clutch 104 is not provided, the rotor 110 is driven to rotate when the bicycle is coasting, and the back electromotive force of the motor part 103 affects the controller.

Because the compound planet wheel unit adopts two-stage speed reduction, the speed reduction ratio is the product of the first-stage speed reduction ratio and the second-stage speed reduction ratio, the assembly volume is the same as the existing 250W in the market, the theoretical speed reduction ratio can reach 25 at most, and the speed reduction ratio is greatly improved.

When the motor part 103 is made into an outer rotor structure, compared with the existing outer rotor toothed hub motor in the market, the reduction ratio is greatly improved, the volume and the material cost of the motor part 103 are greatly reduced, the assembly process is only the assembly of the planet carrier which is repeated once, and the complexity is not improved.

When the motor part 103 is made into an inner rotor structure, compared with the existing inner rotor toothed hub motor in the market, the assembly process is simple, and the structural strength and the assembly precision are also improved because the main shaft 102 is a whole shaft.

The utility model discloses helping hand electric bicycle includes frame, front wheel, rear wheel and the utility model discloses an in-wheel motor, in-wheel motor sets up on the rear wheel. The hub motor can directly drive the rear wheel to rotate, so that the whole electric bicycle is driven to advance. Namely, the electric bicycle is a pure electric vehicle.

It should be noted that in other embodiments, the hub motor may also be disposed on the front wheel.

It should be noted that, in other embodiments, the power-assisted electric bicycle of the present invention further includes a pedal, a pedal crankshaft, a transmission chain, and other components, wherein the pedal crank is connected to the pedal and connected to the wheel through a transmission connection member such as a chain, so as to transmit the power-assisted action to the wheel. When a rider steps on the pedal, the power of the pedal is transmitted to the wheels, and the wheels are finally driven to rotate. The personnel of riding can reach the purpose of riding through stepping on the running-board promptly, and in-wheel motor plays auxiliary drive's effect. The power-assisted electric bicycle can also be used as a bicycle and a power-assisted electric bicycle.

The embodiments of the present invention have been described in detail with reference to the drawings, but the present invention is not limited to the above embodiments, and various changes can be made without departing from the spirit of the present invention within the knowledge of those skilled in the art.

Claims (12)

1. In-wheel motor, its characterized in that includes:

a housing;

the main shaft penetrates through the machine shell and can rotate relative to the machine shell;

the motor part is arranged on the main shaft and comprises a stator and a rotor, the stator is fixedly connected with the main shaft, and the rotor and the main shaft are coaxially arranged and can rotate relatively;

the compound planet wheel unit comprises a primary planet speed reducing system and a secondary planet speed reducing system, wherein the primary planet speed reducing system comprises a first sun wheel, a first gear ring, a first planet wheel and a first planet carrier, the first sun wheel is connected with the rotor, the first gear ring is fixed on the shell, and the first planet wheel is respectively meshed with the first sun wheel and the first gear ring; the secondary planetary reduction system comprises a second sun gear, a second gear ring, a second planetary gear and a second planetary carrier, the second sun gear is fixedly connected to the first planetary carrier, the second gear ring is fixed on the machine shell, and the second planetary gear is respectively meshed with the second sun gear and the second gear ring;

and the second planet carrier is connected with the main shaft through the one-way clutch.

2. The in-wheel motor of claim 1, wherein the housing comprises a casing and an end cap, the casing is coupled to the end cap and forms a cavity, and the motor portion, the compound planetary gear unit, and the one-way clutch are located in the cavity.

3. The in-wheel motor of claim 2, wherein the housing and the end cap are bonded, interference bonded, or screwed.

4. The in-wheel motor of claim 1, wherein the motor portion is an inner rotor motor, an outer rotor motor, or a disc motor structure.

5. The in-wheel motor of claim 1, wherein the one-way clutch is of a sprag, roller or ratchet type construction.

6. The in-wheel motor of claim 1, wherein the one-way clutch comprises a fixed member and a movable member, the fixed member is fixedly connected to the main shaft, the movable member and the second planet carrier are an integrated member, or the movable member and the second planet carrier are bonded, connected in an interference manner, or connected by a screw.

7. The in-wheel motor of claim 1, wherein the first sun gear is integral with the rotor, or the first sun gear and the rotor are overmolded, bonded, interference bonded, or screwed.

8. The in-wheel motor of claim 1, wherein the second sun gear is one piece with the first carrier, or the second sun gear is bonded, interference bonded, or screwed to the first carrier.

9. The in-wheel motor of claim 1, wherein the first ring gear and the second ring gear are of unitary construction or are splined.

10. The in-wheel motor of claim 1, wherein at least one of the first ring gear and the second ring gear is bonded, interference bonded, splined, or bolted to the housing.

11. The in-wheel motor as claimed in claim 1, wherein the motor portion comprises a bracket, the stator is connected to the bracket, and the bracket is bonded, welded, connected with the main shaft in an interference manner, connected with the main shaft through a flat key, a spline or a screw.

12. An electric power assisted bicycle, characterized by comprising the hub motor of any one of claims 1 to 11.

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