Middle motor and power-assisted bicycle

Abstract

The utility model provides a middle motor and a moped, and relates to the technical field of mopeds. The middle motor comprises a shell with a containing cavity and a speed reduction device which is arranged in the containing cavity and comprises an elastic sun gear, an elastic fixed gear ring, an elastic movable gear ring, a planet carrier and a plurality of planet gears. The multiple planet gears are arranged in the circumferential direction of the elastic sun gear at intervals, the elastic fixed gear ring and the elastic movable gear ring are arranged in the axial direction of the middle motor at intervals, and each planet gear is rotationally arranged on the planet carrier and engaged with the elastic sun gear, the elastic fixed gear ring and the elastic movable gear ring. The elastic sun gear and the planet carrier are arranged in a floating mode relative to the shell in the radial direction of the middle motor. Thus, when unbalanced loads are generated, the elastic sun gear, the elastic fixed gear ring and the elastic movable gear ring can generate corresponding elastic deformation, meanwhile, the elastic sun gear and the planet carrier can float in the radial direction of the middle motor to conduct automatic position adjustment, and therefore the loads between the planet gears are balanced.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of power-assisted bicycles, and particularly relates to a middle-mounted motor and a power-assisted bicycle. BACKGROUND

[0002] The information disclosed in this BACKGROUND section is only for the purpose of enhancing the understanding of the general background of the present disclosure and does not necessarily describe prior art that is already known to those skilled in the art.

[0003] A motor installed in the middle position of the body of a power-assisted bicycle is called a middle-mounted motor, the middle-mounted motor is connected with the wheel of the power-assisted bicycle to provide power assistance, meanwhile, pedals of the power-assisted bicycle are installed on both sides of the middle-mounted motor, in the case that the middle-mounted motor has no power supply, the user can realize human-powered riding through the pedals. In the related art, the middle-mounted motor adopts a planetary reduction device as a transmission device, but due to unreasonable structure design, there is an imbalance in the load between the planetary gears, which leads to a reduction in the service life of the middle-mounted motor. CONTENT OF THE UTILITY MODEL

[0004] Therefore, the purpose of the present application is to provide a middle-mounted motor and a power-assisted bicycle, which aims to solve the technical problem of load imbalance between the planetary gears of the reduction device in the related art.

[0005] To achieve the above-mentioned purpose, the technical scheme adopted by the present application is as follows:

[0006] In a first aspect, the embodiments of the present application provide a middle-mounted motor, comprising:

[0007] a housing having a receiving cavity;

[0008] a reduction device arranged in the receiving cavity and comprising an elastic sun gear, an elastic fixed ring gear, an elastic movable ring gear, a planet carrier and a plurality of planetary gears, the plurality of planetary gears are arranged at intervals along the circumferential direction of the elastic sun gear, the elastic fixed ring gear and the elastic movable ring gear are arranged at intervals along the axial direction of the middle-mounted motor, each planetary gear is rotatably arranged on the planet carrier and respectively engaged with the elastic sun gear, the elastic fixed ring gear and the elastic movable ring gear, the elastic sun gear is arranged to be floating relative to the housing along the radial direction of the middle-mounted motor, and the planet carrier is arranged to be floating relative to the housing along the radial direction of the middle-mounted motor.

[0009] In one of the embodiments of the first aspect, the output device further comprises a first bearing and a second bearing which are spaced along the axial direction of the mid-drive motor, the first rotating member is arranged through the output shaft, the inner ring of the first bearing is connected with the first rotating member, the outer ring of the first bearing is connected with the output shaft, the inner ring of the second bearing is connected with the first rotating member, and the outer ring of the second bearing is connected with the housing.

[0010] In one of the embodiments of the first aspect, the output device further comprises a first bearing and a second bearing which are spaced along the axial direction of the mid-drive motor, the first rotating member is arranged through the output shaft, the inner ring of the first bearing is connected with the first rotating member, the outer ring of the first bearing is connected with the output shaft, the inner ring of the second bearing is connected with the first rotating member, and the outer ring of the second bearing is connected with the housing.

[0011] In one of the embodiments of the first aspect, the output device further comprises a first wave spring and a second wave spring, the first wave spring is supported by the first bearing along the axial direction of the mid-drive motor, and the second wave spring is supported by the second bearing along the axial direction of the mid-drive motor.

[0012] In one of the embodiments of the first aspect, the mid-drive motor further comprises a driving device arranged in the accommodating cavity, the driving device has a driving shaft, the driving shaft is arranged with a second connecting hole, a part of the elastic sun gear is arranged through the second connecting hole, the hole wall of the second connecting hole is connected with the outer peripheral side of the elastic sun gear, the planetary carrier is arranged with a third connecting hole, a part of the driving shaft is arranged through the third connecting hole, and the hole wall of the third connecting hole and the outer peripheral side of the driving shaft have a second floating gap.

[0013] In one of the embodiments of the first aspect, the hole wall of the second connecting hole is arranged with a spline hole, the outer peripheral side of the elastic sun gear is arranged with a drum-shaped tooth, the drum-shaped tooth is arranged through the spline hole to limit the relative rotation of the elastic sun gear and the driving shaft.

[0014] In one of the embodiments of the first aspect, the driving device comprises a third bearing and a fourth bearing which are arranged axially along the middle motor, an inner ring of the third bearing is connected with the driving shaft, an outer ring of the third bearing is connected with the shell, an inner ring of the fourth bearing is connected with the driving shaft, and an outer ring of the fourth bearing is connected with the shell, and the third bearing and the fourth bearing are made of stainless steel or ceramic.

[0015] In one of the embodiments of the first aspect, the speed reduction device further comprises a fifth bearing and a sixth bearing, the fifth bearing is supported on one side of the planet carrier along the axial direction of the middle motor, and the sixth bearing is supported on the other side of the planet carrier along the axial direction of the middle motor, and the fifth bearing and the sixth bearing are both planar thrust bearings to limit the movement of the planet carrier relative to the shell along the axial direction of the middle motor.

[0016] In one of the embodiments of the first aspect, each of the planet wheels is rotationally connected with the planet carrier through a connecting shaft, and the speed reduction device further comprises a seventh bearing, an inner ring of the seventh bearing is connected with the connecting shaft, and an outer ring of the seventh bearing is connected with the planet wheel to limit the movement of the planet wheel relative to the planet carrier along the radial direction of the middle motor.

[0017] In the second aspect, the embodiments of the present application provide a power-assisted bicycle comprising the middle motor according to any one of the embodiments of the first aspect.

[0018] The beneficial effects of the present application are as follows:

[0019] The middle motor provided by the present application comprises a shell and a speed reduction device, and the speed reduction device comprises an elastic sun gear, an elastic fixed ring gear and an elastic movable ring gear, and the elastic sun gear is arranged to be floating relative to the shell along the radial direction of the middle motor, and the planet carrier is arranged to be floating relative to the shell along the radial direction of the middle motor. In this way, when an unbalanced load is generated, the elastic sun gear, the elastic fixed ring gear and the elastic movable ring gear can generate corresponding elastic deformation, and at the same time, the elastic sun gear and the planet carrier can float along the radial direction of the middle motor to automatically adjust the position, so that the load between the planet wheels is balanced, the service life of the middle motor is improved, and the noise problem caused by the unbalanced load is improved.

[0020] In order to make the above-mentioned purposes, characteristics and advantages of the present application more obvious and easy to understand, the following preferred embodiments are described in detail below, and the accompanying drawings are described as follows. BRIEF DESCRIPTION OF DRAWINGS

[0021] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the following will briefly introduce the drawings needed to be used in the embodiments. It should be understood that the following drawings only show some of the embodiments of the present application, and therefore should not be regarded as a limitation to the scope, and for those skilled in the art, other related drawings can also be obtained without creative labor on the basis of these drawings.

[0022] Figure 1 A perspective view of the structure of the middle motor in one embodiment of the present application is shown.

[0023] Figure 2 Another perspective view of the structure of the middle motor in one embodiment of the present application is shown.

[0024] Figure 3 A perspective view of the structure of the middle motor in one embodiment of the present application is shown. Figure 2 A cross-sectional view of the structure at A-A is shown.

[0025] Figure 4 A perspective view of the structure of the middle motor in one embodiment of the present application is shown.

[0026] Figure 5 Another perspective view of the structure of the middle motor in one embodiment of the present application is shown. Figure 4 A perspective view of the structure of the middle motor in one embodiment of the present application is shown.

[0027] Figure 6 A perspective view of the structure of the middle motor in one embodiment of the present application is shown.

[0028] Figure 7 Another perspective view of the structure of the middle motor in one embodiment of the present application is shown.

[0029] Figure 8 A perspective view of the structure of the middle motor in one embodiment of the present application is shown.

[0030] Figure 9 Another perspective view of the structure of the middle motor in one embodiment of the present application is shown.

[0031] Figure 10 Another perspective view of the structure of the middle motor in one embodiment of the present application is shown.

[0032] Figure 11 A perspective view of the structure of the middle motor in one embodiment of the present application is shown.

[0033] Main element symbol explanation:

[0034] 100 - middle motor; 110 - housing; 111 - first housing; 112 - second housing; 113 - third housing; 114 - accommodating cavity; 120 - deceleration device; 121 - elastic sun gear; 1211 - first connecting hole; 1212 - bevel gear; 122 - elastic fixed ring gear; 123 - elastic movable ring gear; 124 - planet carrier; 1241 - third connecting hole; 125 - planet gear; 1251 - connecting part; 1252 - first gear part; 1253 - second gear part; 126 - fifth bearing; 127 - sixth bearing; 128 - seventh bearing; 129 - connecting shaft; 130 - output device; 131 - output shaft; 132 - first rotating member; 1321 - first floating gap; 133 - first clutch; 134 - second rotating member; 135 - second clutch; 136 - first bearing; 137 - second bearing; 140 - driving device; 141 - driving shaft; 1411 - second connecting hole; 1412 - second floating gap; 1413 - spline hole; 142 - stator; 143 - rotor; 144 - third bearing; 145 - fourth bearing; X - axial; Y - radial; Z - circumferential. DETAILED DESCRIPTION

[0035] Embodiments of the present application are described below in detail, examples of which are shown in the accompanying drawings, wherein the same or similar notations represent the same or similar elements or elements having the same or similar functions throughout. The embodiments described below by referring to the accompanying drawings are exemplary, only for explaining the present application, and cannot be understood as a limitation of the present application.

[0036] In the description of the present application, the orientation or positional relationship indicated by the terms "center", "longitudinal", "lateral", "length", "width", "height", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential" and the like is based on the orientation or positional relationship shown in the drawings, only for the convenience of describing the present application and simplifying the description, and does not indicate or imply that the device or element referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as a limitation of the present application.

[0037] In addition, unless specifically stated and limited otherwise, the first feature is "on" or "under" the second feature can be that the first feature and the second feature are in direct contact, or the first feature and the second feature are indirectly in contact through an intermediate medium. Moreover, the first feature "above", "over" and "on" the second feature can be that the first feature is directly above or obliquely above the second feature, or only indicates that the first feature is higher in horizontal height than the second feature. The first feature "below", "under" and "under" the second feature can be that the first feature is directly below or obliquely below the second feature, or only indicates that the first feature is lower in horizontal height than the second feature.

[0038] In the description of the present application, the terms "first", "second" and the like are used to distinguish different objects, and cannot be understood as indicating or implying a specific order or primary and secondary relationship, or implicitly indicating the number of the technical features indicated. Therefore, the features defined with "first", "second" can explicitly or implicitly include one or more of the features. In the description of the present application, the meaning of "multiple" is two or more, unless otherwise specifically limited.

[0039] In the description of the present application, unless otherwise specifically stated and limited, the terms "mounting", "connection", "connection", "fixing" and the like should be understood in a broad sense, for example, it can be fixedly connected, or it can be detachably connected, or it can be integrated; it can be mechanically connected, or it can be electrically connected; it can be directly connected, or it can be indirectly connected through an intermediate medium; it can be the internal communication of two elements or the interaction relationship between two elements. For those skilled in the art, the specific meaning of the above terms in the present application can be understood according to the specific circumstances.

[0040] In the description of the present application, the term "and / or" indicates that there can be three relationships, for example, A and / or B, which can represent the three cases of A alone, A and B together, and B alone. In addition, the character " / ", in general, indicates that the front and rear associated objects are in an "or" relationship.

[0041] In the description of the present application, "parallel" not only includes the case of absolute parallel, but also includes the case of approximate parallel which is generally recognized in engineering; at the same time, "vertical" not only includes the case of absolute vertical, but also includes the case of approximate vertical which is generally recognized in engineering. Illustratively, the included angle between two directions is 80°-90°, which can be considered as two directions vertical; the included angle between two directions is 0°-10°, which can be considered as two directions parallel.

[0042] The power-assisted bicycle is a new type of transportation tool capable of realizing the integration of human riding and motor assistance. The motor installed in the middle position of the body of the power-assisted bicycle is called a middle motor, which is connected with the wheel of the power-assisted bicycle to assist, and the pedals of the power-assisted bicycle are installed on both sides of the middle motor. In the related art, the middle motor adopts a planetary reduction device as a transmission device, but due to unreasonable structure design, there is an imbalance between the loads of the planetary gears, resulting in noise of the middle motor and reduction of service life.

[0043] To solve the above technical problems, as shown in Figure 1 The embodiment of the present application provides a middle motor 100, which relates to the technical field of power-assisted bicycles and is applied to a power-assisted bicycle to assist the user in riding.

[0044] In combination Figures 2 to 5 The middle motor 100 provided by the embodiment has a radial direction Y and an axial direction X, and comprises an outer shell 110 and a reduction device 120.

[0045] The outer shell 110 has a containing cavity 114, and the reduction device 120 is arranged in the containing cavity 114 and comprises an elastic sun gear 121, an elastic fixed gear ring 122, an elastic movable gear ring 123, a planet carrier 124 and a plurality of planetary gears 125. The plurality of planetary gears 125 are arranged at intervals along the circumferential direction Z of the elastic sun gear 121. The elastic fixed gear ring 122 and the elastic movable gear ring 123 are arranged at intervals along the axial direction X of the middle motor 100. Each planetary gear 125 is rotatably arranged on the planet carrier 124 and is respectively engaged with the elastic sun gear 121, the elastic fixed gear ring 122 and the elastic movable gear ring 123. The elastic sun gear 121 is arranged to be floating relative to the outer shell 110 along the radial direction Y of the middle motor 100. The planet carrier 124 is arranged to be floating relative to the outer shell 110 along the radial direction Y of the middle motor 100.

[0046] It should be noted that the three gears, i.e. the elastic sun gear 121, the elastic fixed gear ring 122 and the elastic movable gear ring 123, have elastic deformation capability. Specifically, thin-wall design can be adopted, i.e. the wall thickness of the three gears is reduced in the processing stage, so that the three gears have a certain elasticity, or a material with high elasticity, high toughness and good comprehensive mechanical properties is used to make the three gears have a certain elasticity, such as some high-strength alloy steel or special engineering plastic.

[0047] In addition, the elastic sun gear 121 and the planet carrier 124 are arranged to be floating relative to the outer shell 110 along the radial direction Y of the middle motor 100, which means that the elastic sun gear 121 and the planet carrier 124 are not supported and limited in the radial direction Y, so that they can float in the radial direction Y of the middle motor 100.

[0048] It can be understood that the intermediate motor 100 provided by the embodiment has the elastic sun gear 121, the elastic fixed gear ring 122 and the elastic movable gear ring 123, and the elastic sun gear 121 is arranged to be floating relative to the shell 110 along the radial direction Y of the intermediate motor 100, and the planet carrier 124 is arranged to be floating relative to the shell 110 along the radial direction Y of the intermediate motor 100. In this way, when unbalanced load is generated, the elastic sun gear 121, the elastic fixed gear ring 122 and the elastic movable gear ring 123 can generate corresponding elastic deformation, and at the same time, the elastic sun gear 121 and the planet carrier 124 can be floating along the radial direction Y of the intermediate motor 100 to be automatically positioned, so that the load between the planet gears 125 is balanced (especially when the number of planet gears 125 is three and the intermediate motor 100 is applied to low-speed planetary transmission, the load balancing effect is better), so that the service life of the intermediate motor 100 is improved, and the noise problem caused by unbalanced load is improved.

[0049] As shown in Figures 2 to 5 In one embodiment, the intermediate motor 100 further includes an output device 130, the output device 130 includes an output shaft 131, a first rotating part 132 and a first clutch 133, the output shaft 131 and the first clutch 133 are located in the accommodating cavity 114, at least part of the first rotating part 132 is located in the accommodating cavity 114, the output shaft 131 is connected with the elastic movable gear ring 123, the first rotating part 132 is used for connecting the pedal of the assisted bicycle, the first clutch 133 is arranged between the output shaft 131 and the first rotating part 132, and is used for realizing the connection and separation between the first rotating part 132 and the output shaft 131, the elastic sun gear 121 is provided with a first connecting hole 1211, the first rotating part 132 is arranged to pass through the first connecting hole 1211, and the first floating gap 1321 is formed between the hole wall of the first connecting hole 1211 and the outer circumferential side of the first rotating part 132.

[0050] It can be understood that the elastic sun gear 121 is provided with the first connecting hole 1211, the first rotating part 132 is arranged to pass through the first connecting hole 1211, and the first floating gap 1321 is formed between the hole wall of the first connecting hole 1211 and the outer circumferential side of the first rotating part 132. In this way, the elastic sun gear 121 can be floating along the radial direction Y of the intermediate motor 100 to be automatically positioned, so that the load between the planet gears 125 is balanced.

[0051] As shown in Figures 2 to 4As shown, further, the output device 130 further comprises a first bearing 136 and a second bearing 137 which are arranged along the axial direction X of the central motor 100, the first rotating member 132 is arranged through the output shaft 131, the inner ring of the first bearing 136 is connected with the first rotating member 132, the outer ring of the first bearing 136 is connected with the output shaft 131, the inner ring of the second bearing 137 is connected with the first rotating member 132, and the outer ring of the second bearing 137 is connected with the housing 110, thereby the first rotating member 132 can be limited to move along the radial direction Y of the central motor 100, so as to reduce the possibility of the first rotating member 132 moving along the radial direction Y of the central motor 100 during transmission, and prolong the service life of the central motor 100.

[0052] Further, the output device 130 further comprises a first wave spring and a second wave spring, the first wave spring is arranged along the axial direction X of the central motor 100 and supports the first bearing 136, and the second wave spring is arranged along the axial direction X of the central motor 100 and supports the second bearing 137. In this way, the elastic force generated by the wave spring can be used to pre-tighten the bearing, so as to effectively improve the bearing noise problem under low load operation.

[0053] As shown in Figures 2 to 5 , further, the output device 130 further comprises a second rotating member 134 and a second clutch 135, the second rotating member 134 is used to connect the wheel of the assisted bicycle, and the second clutch 135 is arranged between the second rotating member 134 and the output shaft 131, and is used to realize the connection and separation between the second rotating member 134 and the output shaft 131.

[0054] As shown in Figure 2 , Figure 3 , Figure 5 and Figure 9 , in one embodiment, the central motor 100 further comprises a driving device 140 arranged in the accommodating cavity 114, the driving device 140 has a driving shaft 141, the driving shaft 141 is provided with a second connecting hole 1411, a part of the elastic sun gear 121 is arranged through the second connecting hole 1411, the hole wall of the second connecting hole 1411 is connected with the outer circumferential side of the elastic sun gear 121, the planetary carrier 124 is provided with a third connecting hole 1241, a part of the driving shaft 141 is arranged through the third connecting hole 1241, and the second floating gap 1412 is formed between the hole wall of the third connecting hole 1241 and the outer circumferential side of the driving shaft 141.

[0055] It can be understood that, due to the third connecting hole 1241 arranged on the planet carrier 124, a part of the driving shaft 141 is arranged through the third connecting hole 1241, and the second floating gap 1412 is formed between the hole wall of the third connecting hole 1241 and the outer circumferential side of the driving shaft 141. In this way, the planet carrier 124 can be automatically positioned by floating along the radial direction Y of the in-wheel motor 100, so as to balance the load between the planet gears 125.

[0056] As shown in Figure 2 and Figure 3 , further, the hole wall of the second connecting hole 1411 is arranged with a spline hole 1413, and the outer circumferential side of the elastic sun gear 121 is arranged with a drum gear 1212 arranged through the spline hole 1413, so as to limit the relative rotation between the elastic sun gear 121 and the driving shaft 141.

[0057] It can be understood that, by the cooperation of the drum gear 1212 and the spline hole 1413, the elastic sun gear 121 is connected to the driving shaft 141 in a floating manner along the radial direction Y of the in-wheel motor 100. In this way, not only the torque can be transmitted from the driving shaft 141 to the elastic sun gear 121, but also the automatic positioning function can be realized when the load between the planet gears 125 is unbalanced, so as to balance the load between the planet gears 125.

[0058] As shown in Figure 2 and Figure 3 , further, the driving device 140 comprises a third bearing 144 and a fourth bearing 145 arranged in the axial direction X of the in-wheel motor 100, the inner ring of the third bearing 144 is connected with the driving shaft 141, the outer ring of the third bearing 144 is connected with the housing 110, the inner ring of the fourth bearing 145 is connected with the driving shaft 141, and the outer ring of the fourth bearing 145 is connected with the housing 110, so as to limit the possibility of the driving shaft 141 moving in the radial direction Y of the in-wheel motor 100, and at the same time, the third bearing 144 and the fourth bearing 145 are made of stainless steel or ceramic, so as to improve the electromagnetic influence of the in-wheel motor 100.

[0059] As shown in Figures 2 to 4 , further, the driving device 140 comprises a stator 142 and a rotor 143, the rotor 143 is arranged in a rotating manner through the stator 142, and is connected with the driving shaft 141, the rotor 143 can rotate relative to the stator 142 to drive the driving shaft 141 to rotate, so as to transmit power to the speed reducer 120 through the driving shaft 141.

[0060] As shown in Figure 2 , Figure 3 , Figure 6 and Figure 7As shown in the drawings, in one embodiment, the speed reducer 120 further comprises a fifth bearing 126 and a sixth bearing 127, the fifth bearing 126 is supported on the side of the planet carrier 124 along the axial direction X of the in-wheel motor 100, the sixth bearing 127 is supported on the other side of the planet carrier 124 along the axial direction X of the in-wheel motor 100, both the fifth bearing 126 and the sixth bearing 127 are planar thrust bearings, to limit the movement of the planet carrier 124 along the axial direction X of the in-wheel motor 100 relative to the housing 110, thereby reducing the possibility of the planet carrier 124 moving during transmission, prolonging the service life of the in-wheel motor 100.

[0061] As shown in the drawings, Figure 2 , Figure 3 and Figure 8 As shown in the drawings, in one embodiment, each planet wheel 125 is rotatably connected with the planet carrier 124 through a connecting shaft 129, and the speed reducer 120 further comprises a seventh bearing 128, the inner ring of the seventh bearing 128 is connected with the connecting shaft 129, and the outer ring of the seventh bearing 128 is connected with the planet wheel 125, to limit the movement of the planet wheel 125 along the radial direction Y of the in-wheel motor 100 relative to the planet carrier 124, thereby reducing the possibility of the planet wheel 125 moving during transmission, prolonging the service life of the in-wheel motor 100.

[0062] As shown in the drawings, Figures 8 to 10 Further, each planet wheel 125 comprises a connecting portion 1251, a first toothed portion 1252 and a second toothed portion 1253, the connecting shaft 129 is rotatably arranged in the connecting portion 1251, the outer ring of the seventh bearing 128 is connected with the connecting portion 1251, the first toothed portion 1252 and the second toothed portion 1253 are coaxially arranged and respectively annularly arranged on the outer circumferential side of the connecting portion 1251, the first toothed portion 1252 is respectively engaged with the elastic sun gear 121 and the elastic fixed ring gear 122, and the second toothed portion 1253 is engaged with the elastic movable ring gear 123, so that each planet wheel 125 is respectively engaged with the elastic sun gear 121, the elastic fixed ring gear 122 and the elastic movable ring gear 123.

[0063] Exemplarily, the tooth shape of the first toothed portion 1252 and / or the tooth shape of the second toothed portion 1253 can be selected as straight teeth or helical teeth, which is not specifically limited here.

[0064] It can be understood that each planet wheel 125 comprises the first toothed portion 1252 and the second toothed portion 1253, i.e. each planet wheel 125 is a double coaxial planetary gear, which can improve the transmission speed ratio of the in-wheel motor 100 and reduce the volume and weight of the in-wheel motor 100.

[0065] Exemplarily, when the speed reducer 120 with double coaxial planetary gears selects a 3K type planetary speed reduction transmission structure, the transmission speed ratio range that can be achieved is 20-100 (including 20 and 100).

[0066] Further, the seventh bearing 128 is a cage needle bearing, which has the characteristics of compact structure, small occupied volume, and can further reduce the weight and volume of the middle motor 100, and realize the miniaturization and light weight of the whole machine.

[0067] As shown in Figure 2 , Figure 3 and Figure 11 , it should be noted that the shell 110 can include a first shell 111, a second shell 112 and a third shell 113, the second shell 112 is connected between the first shell 111 and the second shell 112, the first shell 111, the second shell 112 and the third shell 113 enclose the accommodating cavity 114, the drive device 140 and the speed reducer 120 are located in the accommodating cavity 114, the output shaft 131 is located in the accommodating cavity 114, at least part of the first rotating part 132 is located in the accommodating cavity 114, at least part of the second rotating part 134 is located in the accommodating cavity 114, and the elastic fixing ring gear 122 is fixedly connected with the second shell 112.

[0068] Exemplarily, the fixed connection of the elastic fixing ring gear 122 and the second shell 112 can be screw connection, buckle connection, magnetic attraction connection, adhesive connection, quick release connection, etc., which is not specifically limited here.

[0069] It can be understood that by dividing the shell 110 into the first shell 111, the second shell 112 and the third shell 113, the three can be processed independently, the processing precision is easier to guarantee, the processing difficulty is reduced and the processing time is shortened.

[0070] In addition, by accommodating the drive device 140, the speed reducer 120 and the output device 130 in the shell 110, the protection effect can be achieved, such as dustproof, waterproof and the like, thereby prolonging the service life of the middle motor 100.

[0071] In a second aspect, the embodiments of the present application provide a power-assisted bicycle, which comprises a vehicle body, a vehicle wheel, a pedal, a crank, a sprocket and the middle motor 100 in any one of the embodiments of the first aspect, the middle motor 100 and the vehicle wheel are arranged on the vehicle body, the crank is connected between the first rotating part 132 and the pedal, and the sprocket is connected between the second rotating part 134 and the vehicle wheel.

[0072] It can be understood that when the power-assisted bicycle provided by the embodiment is used, the driving device 140 drives the elastic sun gear 121 to rotate through the driving shaft 141, the elastic sun gear 121 drives the plurality of planet gears 125 to revolve and rotate, the plurality of planet gears 125 drive the elastic movable ring gear 123 to rotate, and the elastic movable ring gear 123 transmits the power provided by the driving device 140 to the output shaft 131. In this process, the speed reduction device 120 plays a role of speed reduction and torque increase between the driving device 140 and the output device 130.

[0073] For example, when the user pedals the pedals by means of the cranks to make the first rotating part 132 rotate in the first direction to make the power-assisted bicycle move forward, the first clutch 133 is in the engaged state, so that the first rotating part 132 is connected with the output shaft 131 through the first clutch 133; when the power-assisted bicycle moves backward or the user pedals the pedals by means of the cranks to make the first rotating part 132 rotate in the second direction opposite to the first direction, the first clutch 133 is in the disengaged state, so that the first rotating part 132 is disconnected from the output shaft 131 to cut off the power transmission between the first rotating part 132 and the output shaft 131. For example, when the driving shaft 141 rotates in the first rotating direction, the second clutch 135 is in the engaged state, so that the second rotating part 134 connected with the chain wheel is connected with the output shaft 131 through the second clutch 135, thereby assisting the power-assisted bicycle; when the driving shaft 141 rotates in the second rotating direction opposite to the first rotating direction, the second clutch 135 is in the disengaged state, so that the second rotating part 134 is disconnected from the output shaft 131 to cut off the power transmission between the second rotating part 134 and the output shaft 131.

[0074] It should be understood that, since the electric power-assisted bicycle provided by the embodiment has the above-mentioned electric motor 100 in any one of the embodiments of the first aspect, the electric power-assisted bicycle has all the beneficial effects of the electric motor 100, which will not be described herein.

[0075] In the description of the specification, the description of the terms "one embodiment", "some embodiments", "an example", "a specific example", or "some examples" and the like means that the specific features, structures, materials or characteristics described in connection with the embodiment or example are included in at least one embodiment or example of the present application. In the specification, the illustrative description of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any appropriate manner in any one or more embodiments or examples. In addition, the person skilled in the art can combine and combine the different embodiments or examples described in the specification and the features of the different embodiments or examples without contradiction.

[0076] Although the embodiments of the present application have been shown and described above, it is understood that the above-described embodiments are exemplary and are not to be construed as limiting the present application, and that changes, modifications, substitutions and variations can be made by those skilled in the art without departing from the scope of the present application.

Claims

1. A mid-drive motor, characterized in that, include: The outer shell has a receiving cavity; A speed reduction device is disposed within the receiving cavity and includes an elastic sun gear, an elastic fixed gear ring, an elastic movable gear ring, a planet carrier, and multiple planet gears. The multiple planet gears are spaced apart circumferentially along the elastic sun gear. The elastic fixed gear ring and the elastic movable gear ring are spaced apart axially along the central motor. Each planet gear is rotatably disposed on the planet carrier and meshes with the elastic sun gear, the elastic fixed gear ring, and the elastic movable gear ring, respectively. The elastic sun gear is floating relative to the housing along the radial direction of the central motor, and the planet carrier is floating relative to the housing along the radial direction of the central motor.

2. The mid-mounted motor according to claim 1, characterized in that, The mid-mounted motor further includes an output device, which includes an output shaft, a first rotating member, and a first clutch. The output shaft and the first clutch are located within the receiving cavity. At least a portion of the first rotating member is located within the receiving cavity. The output shaft is connected to the elastic movable gear ring. The first rotating member is used to connect to the pedals of the electric bicycle. The first clutch is disposed between the output shaft and the first rotating member. The elastic sun gear is provided with a first connecting hole. The first rotating member passes through the first connecting hole. A first floating gap exists between the hole wall of the first connecting hole and the outer peripheral side of the first rotating member.

3. The mid-mounted motor according to claim 2, characterized in that, The output device further includes a first bearing and a second bearing spaced apart along the axial direction of the central motor. The first rotating member passes through the output shaft. The inner ring of the first bearing is connected to the first rotating member, and the outer ring of the first bearing is connected to the output shaft. The inner ring of the second bearing is connected to the first rotating member, and the outer ring of the second bearing is connected to the outer casing.

4. The mid-mounted motor according to claim 3, characterized in that, The output device further includes a first wave spring and a second wave spring. The first wave spring is supported on the first bearing along the axial direction of the mid-mount motor, and the second wave spring is supported on the second bearing along the axial direction of the mid-mount motor.

5. The mid-mounted motor according to claim 1, characterized in that, The mid-mounted motor also includes a drive device disposed within the receiving cavity. The drive device has a drive shaft with a second connecting hole. A portion of the elastic sun gear passes through the second connecting hole, and the wall of the second connecting hole is connected to the outer peripheral side of the elastic sun gear. The planet carrier has a third connecting hole, and a portion of the drive shaft passes through the third connecting hole. A second floating gap exists between the wall of the third connecting hole and the outer peripheral side of the drive shaft.

6. The mid-mounted motor according to claim 5, characterized in that, The second connecting hole has a spline hole on its wall, and the outer periphery of the elastic sun gear has a drum-shaped tooth. The drum-shaped tooth passes through the spline hole to restrict the relative rotation of the elastic sun gear and the drive shaft.

7. The mid-mounted motor according to claim 5, characterized in that, The drive device includes a third bearing and a fourth bearing spaced apart along the axial direction of the central motor. The inner ring of the third bearing is connected to the drive shaft, and the outer ring of the third bearing is connected to the housing. The inner ring of the fourth bearing is connected to the drive shaft, and the outer ring of the fourth bearing is connected to the housing. Both the third bearing and the fourth bearing are made of stainless steel or ceramic.

8. The mid-drive motor according to any one of claims 1 to 7, characterized in that, The reduction gear also includes a fifth bearing and a sixth bearing. The fifth bearing is supported on one side of the planetary carrier along the axial direction of the central motor, and the sixth bearing is supported on the other side of the planetary carrier along the axial direction of the central motor. Both the fifth and sixth bearings are planar thrust bearings to limit the movement of the planetary carrier relative to the housing along the axial direction of the central motor.

9. The mid-drive motor according to any one of claims 1 to 7, characterized in that, Each of the planetary gears is rotatably connected to the planetary carrier via a connecting shaft. The reduction gear also includes a seventh bearing, the inner ring of which is connected to the connecting shaft, and the outer ring of which is connected to the planetary gear, to restrict the planetary gear from moving relative to the planetary carrier along the radial direction of the central motor.

10. A power-assisted bicycle, characterized in that, Includes the mid-drive motor as described in any one of claims 1 to 9.

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