A kind of middle motor drive system, middle motor and electric bicycle

Abstract

The application discloses a middle motor transmission system, a middle motor and an electric bicycle. The middle motor transmission system comprises a motor assembly, a first transmission wheel set comprising a first transmission gear and a first transmission gear shaft coaxially connected, a second transmission wheel set in meshing transmission with the first transmission gear shaft, and a middle shaft gear in meshing transmission with the second transmission wheel set. The first transmission gear shaft comprises an input end, an output gear part and a support shaft. The input end is connected with the first transmission gear. The output gear part is located between the input end and the support shaft. The diameter of the support shaft is smaller than that of the output gear part and the input end. The support shaft is connected with a first needle bearing. The middle motor transmission system provided by the application supports the transmission end of the first transmission gear shaft through the needle bearing, thereby overcoming the problem of serious one-side wear of the first transmission gear shaft in the transmission process due to the suspension state.

Description

Technical Field

[0001] This invention relates to the field of electrical engineering, and in particular to a mid-drive motor drive system, a mid-drive motor, and an electric bicycle. Background Technology

[0002] The existing mid-drive motor structure using a three-stage transmission system typically has large radii for both the primary transmission gear and the central shaft gear. This results in a small space between the primary transmission gear set (including the driven gear and the driven gear shaft) and the central shaft gear, and a small transmission ratio for the secondary transmission gear set (meaning the diameters of the two gears in the secondary transmission gear set are relatively similar). Consequently, the output end of the primary transmission gear shaft cannot be fitted with a conventional support structure on the main housing (i.e., a ball bearing is designed at the shaft end) and remains suspended. During the transmission process of the primary transmission gear shaft, it is constantly subjected to unidirectional torque, leading to severe wear on the primary driven gear shaft. Summary of the Invention

[0003] The technical problem to be solved by the embodiments of the present invention is to provide a mid-drive motor transmission system, a mid-drive motor and an electric bicycle, which solves the problem that the output end of the first-stage drive gear shaft in the existing three-stage transmission mid-drive motor is in a suspended state, resulting in severe wear of the first-stage driven gear shaft.

[0004] To solve the above-mentioned technical problems, the present invention provides a mid-mounted motor drive system, comprising:

[0005] Motor assembly, including shaft;

[0006] A primary transmission gear set includes a primary transmission gear and a primary transmission gear shaft, wherein the primary transmission gear meshes with the rotating shaft, and the primary transmission gear shaft is coaxially connected to the primary transmission gear;

[0007] The secondary transmission gear set meshes with the primary transmission gear shaft for transmission;

[0008] The central shaft gear meshes with the secondary transmission gear set for transmission;

[0009] The primary transmission gear shaft includes an input end, an output tooth section, and a support shaft. The input end is connected to the primary transmission gear, the output tooth section is located between the input end and the support shaft, the diameter of the support shaft is smaller than the diameter of the output tooth section and the input end, and the support shaft is connected to a first needle roller bearing.

[0010] Optionally, the outer diameter of the first needle roller bearing is smaller than the tip circle diameter of the output teeth.

[0011] Optionally, the secondary transmission gear set includes a secondary transmission large gear and a secondary transmission small gear coaxially connected. The secondary transmission large gear meshes with the primary transmission gear shaft, and the secondary transmission small gear meshes with the central shaft gear. The secondary transmission small gear is located on the side away from the primary transmission gear shaft, so that the position of the secondary transmission small gear corresponds to the position of the first needle roller bearing in the radial direction.

[0012] Optionally, the primary transmission gear shaft passes through the bearing bracket, and the support shaft is mounted in the first bearing mounting hole on the inner wall of the main unit cover via the first needle roller bearing.

[0013] Optionally, the bearing bracket is connected between the main housing and the main cover to form a reduction chamber, which houses the first-stage transmission wheel set and the second-stage transmission wheel set.

[0014] Optionally, a second bearing mounting hole is provided on the inner wall of the main unit cover, and the shaft of the secondary transmission pinion is mounted in the second bearing mounting hole through a fourth ball bearing.

[0015] Optionally, the first bearing mounting hole is tangent to the second bearing mounting hole or communicates with the sidewall.

[0016] Optionally, the rotational axis distance Z between the secondary transmission wheel set and the primary transmission gear set is 10-20mm.

[0017] Optionally, the rotational axis distance Z between the secondary transmission wheel set and the primary transmission gear set is 15.3 mm.

[0018] Optionally, the diameter of the first needle roller bearing is 5.5-10.5 mm.

[0019] Optionally, the diameter of the first needle roller bearing is 8 mm.

[0020] Optionally, it also includes a central shaft drive mechanism, the central shaft drive mechanism comprising:

[0021] Central axis;

[0022] The torque sensor is fixedly mounted on the central shaft;

[0023] The tooth plate positioning sleeve has one end connected to the torque sensor via a first one-way valve, and the other end fixedly connected to the tooth plate;

[0024] The central shaft gear is connected to the toothed locating sleeve via a second one-way device; and the central shaft gear meshes with the secondary transmission pinion.

[0025] Optionally, the central shaft gear includes:

[0026] Gear section;

[0027] The support portion is located on the inner side of the gear portion in the radial direction and is used to connect to the toothed disc positioning sleeve via a third ball bearing.

[0028] The transmission part, located on one side of the support part in the axial direction, is used to connect with the toothed disc positioning sleeve via the second one-way device.

[0029] Optionally, the gear portion, the support portion, and the transmission portion form an L-shaped layout, and in the axial direction, the transmission portion is located outside the support portion.

[0030] Optionally, the toothed disc positioning sleeve has an annular stepped structure, wherein the first one-way valve is disposed in the annular stepped structure, the second one-way valve is close to the annular stepped structure, and the outer diameter of the transmission part does not exceed the outer diameter of the annular stepped structure.

[0031] Optionally, the toothed disc positioning sleeve is connected to the central shaft by two needle roller bearings, and the two needle roller bearings are located on both sides of the support.

[0032] Optionally, the two needle roller bearings are a second needle roller bearing and a third needle roller bearing, wherein the second needle roller bearing is located outside the third needle roller bearing, and the third needle roller bearing is connected to the torque sensor.

[0033] Optionally, the inner diameter of the third needle roller bearing is larger than the inner diameter of the second needle roller bearing.

[0034] Optionally, the torque sensor is fixedly connected to the central shaft via a spline; the central shaft is a hollow tubular shaft, and its two ends are respectively connected to a crank.

[0035] Optionally, the primary transmission gear includes a central insert and an outer ring gear. The central insert has a central hole, and the outer ring gear is connected to the outer circumference of the central insert and arranged coaxially. The axial width of the outer ring gear is greater than the axial width of the central insert, and both ends of the outer ring gear extend beyond the central insert in the axial direction. The central insert is made of metal, and the outer ring gear is made of non-metallic material.

[0036] Optionally, the outer circumferential surface of the central insert is provided with a reinforcing structure; the reinforcing structure protrudes or is recessed into the surface of the outer circumference.

[0037] Optionally, the reinforcing structure is a set of reinforcing teeth, knurling, or splines evenly distributed around the outer circumference of the central insert.

[0038] Optionally, the reinforcing tooth is divided into at least three segments in the axial direction.

[0039] Optionally, the top surface of the reinforcing tooth is an arc surface or a surface with an obtuse angle.

[0040] The protruding top must not be made into a sharp corner, and the width of the top should not be less than 0.2mm to avoid stress concentration during injection molding. Furthermore, sharp corners are more prone to breakage when subjected to high torque.

[0041] Optionally, the number of splines is not less than 4, and the spline modulus is not less than 0.25.

[0042] Optionally, the outer ring teeth are injection molded into the outer circumference of the central insert.

[0043] Optionally, the rotating shaft includes a shaft-shaped portion and a toothed portion. The surface of the toothed portion is machined to extend to the end of the shaft. The toothed portion includes an engaging region and a non-engaging region. The engaging region is connected to the shaft-shaped portion. The non-engaging region is located at the free end of the rotating shaft. The toothed surface in the non-engaging region is provided with a circumferentially cut partition groove, or the toothed surface at the junction of the engaging region and the non-engaging region is provided with a circumferentially cut partition groove.

[0044] Optionally, the depth of the partition groove does not exceed the height of the tooth surface; and or, the length between the partition groove and the end of the tooth does not exceed one-third of the length of the tooth surface.

[0045] Optionally, a groove is provided on the end face of the rotating shaft at one end of the shaft-shaped portion, and an induction magnet is installed in the groove.

[0046] Optionally, the groove is circular and has an inner conical surface at its center.

[0047] Optionally, the diameter of the groove is smaller than the diameter of the root circle.

[0048] Optionally, the induction magnet is also circular, and the diameter of the induction magnet is slightly larger than the diameter of the groove, so that the induction magnet is installed in the groove by an interference fit;

[0049] Alternatively, the inductive magnet is connected in the groove via a colloid.

[0050] Optionally, the tooth surface is a helical tooth or a straight tooth.

[0051] The present invention also provides a mid-drive motor, including the aforementioned transmission system.

[0052] The present invention also provides an electric bicycle, including the aforementioned transmission system.

[0053] Implementing this invention has the following beneficial effects:

[0054] The mid-drive motor transmission system provided by this invention features a support shaft at the end of the primary drive gear shaft. This support shaft has a smaller diameter and is connected to a needle roller bearing with a relatively small diameter. The needle roller bearing supports the transmission end of the primary drive gear shaft, thereby overcoming the problem of severe unilateral wear caused by the primary drive gear shaft being suspended in the air during transmission. This ensures more stable transmission of the system and reduces unilateral wear of the primary drive gear shaft during transmission.

[0055] It should be understood that the above general description and the following detailed description are exemplary and explanatory only, and do not limit this application. Attached Figure Description

[0056] The accompanying drawings, which are incorporated in and form part of this specification, illustrate embodiments consistent with this application and, together with the description, serve to explain the principles of this application, and do not constitute an undue limitation of this application.

[0057] Figure 1 This is a schematic diagram of the rotor core structure in an embodiment of the present invention;

[0058] Figure 2 yes Figure 1 A magnified view of a portion of point A in the middle;

[0059] Figure 3 This is a schematic diagram of the structure of the open-structure iron core lamination in an embodiment of the present invention;

[0060] Figure 4 This is a three-dimensional schematic diagram of the open-structure iron core lamination in an embodiment of the present invention;

[0061] Figure 5 This is a schematic diagram of the closed-structure iron core lamination in an embodiment of the present invention;

[0062] Figure 6 This is a three-dimensional schematic diagram of a closed-structure iron core lamination in an embodiment of the present invention;

[0063] Figure 7 This is a schematic diagram of the structure of the open-structure iron core lamination in an embodiment of the present invention;

[0064] Figure 8 This is a schematic diagram of the rotor structure in an embodiment of the present invention;

[0065] Figure 9 This is a cross-sectional schematic diagram of the rotor in an embodiment of the present invention;

[0066] Figure 10 This is a schematic diagram of the rotor assembly in an embodiment of the present invention;

[0067] Figure 11This is a schematic diagram of the rotor assembly in an embodiment of the present invention;

[0068] Figure 12 This is a schematic diagram of the structure of the rotating shaft in an embodiment of the present invention;

[0069] Figure 13 This is a schematic diagram of the structure of the first-stage transmission wheel assembly in an embodiment of the present invention;

[0070] Figure 14 This is a cross-sectional view of the first-stage transmission wheel assembly in an embodiment of the present invention;

[0071] Figure 15 This is a schematic diagram of the structure of the first-stage transmission gear in an embodiment of the present invention;

[0072] Figure 16 This is a cross-sectional view of the primary transmission gear in an embodiment of the present invention;

[0073] Figure 17 This is a schematic diagram of the structure of the central insert in an embodiment of the present invention;

[0074] Figure 18 This is a schematic diagram of the structure of the first-stage transmission gear shaft in an embodiment of the present invention;

[0075] Figure 19 This is a schematic diagram of the assembly structure of the secondary transmission wheel set in an embodiment of the present invention;

[0076] Figure 20 This is a schematic diagram of the structure of the central shaft transmission mechanism in an embodiment of the present invention;

[0077] Figure 21 This is a cross-sectional view of the shaft transmission mechanism in an embodiment of the present invention;

[0078] Figure 22 This is a schematic diagram of the structure of the central shaft gear in an embodiment of the present invention;

[0079] Figure 23 This is a cross-sectional view of the central shaft gear in an embodiment of the present invention;

[0080] Figure 24 This is a partial structural schematic diagram of the transmission system in an embodiment of the present invention;

[0081] Figure 25 This is a partial structural schematic diagram of the transmission system in an embodiment of the present invention;

[0082] Figure 26 This is a partial structural schematic diagram of the transmission system in an embodiment of the present invention;

[0083] Figure 27 This is a schematic diagram of the structure of the mid-mounted motor in an embodiment of the present invention;

[0084] Figure 28 This is an embodiment of the present invention. Figure 27 Sectional view of section AA;

[0085] Figure 29 This is a cross-sectional view of the mid-mounted motor in an embodiment of the present invention;

[0086] Figure 30 This is a schematic diagram of the structure of the rotating shaft (2300A) in an embodiment of the present invention;

[0087] Figure 31 This is a cross-sectional view of the mid-mounted motor in an embodiment of the present invention;

[0088] Figure 32 This is a schematic diagram of the assembly structure of the mid-mounted motor in an embodiment of the present invention;

[0089] Figure 33 This is a schematic diagram of the structure of the rotating shaft (2300B) in an embodiment of the present invention;

[0090] Figure 34 This is a cross-sectional view of the mid-mounted motor in an embodiment of the present invention;

[0091] Figure 35 This is a three-dimensional structural diagram of the mid-mounted motor in an embodiment of the present invention;

[0092] Figure 36 This is a schematic diagram of the main unit cover and its installation structure with the rotary transformer in an embodiment of the present invention;

[0093] Figure 37 This is a schematic diagram of the mid-mounted motor structure after removing the main unit cover in an embodiment of the present invention;

[0094] Figure 38 This is a schematic diagram of the main unit cover in an embodiment of the present invention;

[0095] Figure 39 This is a schematic diagram of the assembly structure of the mid-mounted motor in an embodiment of the present invention;

[0096] Figure 40 This is a partial structural schematic diagram of the transmission system in an embodiment of the present invention.

[0097] The reference numerals in the figure are: 1000 - main housing; 1001 - motor mounting cavity; 1002 - resolver mounting cavity; 1003 - transmission cavity;

[0098] 1010 - Stator mounting section; 1011 - Annular groove;

[0099] 1020 - Partition plate; 1022 - Second bearing mounting chamber; 1023 - Second ball bearing;

[0100] 1030 - Heat dissipation fins;

[0101] 1100 - Motor cover; 1110 - First bearing mounting chamber; 1111 - First ball bearing;

[0102] 1200 - Transition shell;

[0103] 1210 - Shaft hole;

[0104] 1220 - Annular rib; 1230 - Fixing block; 1240 - Bearing mounting chamber;

[0105] 1300 - Main unit cover; 1310 - First bearing mounting hole; 1320 - Second bearing mounting hole;

[0106] 2000 - Motor Assembly;

[0107] 2100-Stator;

[0108] 2200-rotor core;

[0109] 2210 - Core lamination; 2211 - Notch; 2212 - Shaft hole; 2213 - Core yoke; 2214 - Core teeth;

[0110] 2215 - Magnet mounting slot; 2216 - Pole shoe; 2217 - Magnetic shielding strip; 2218 - Round hole; 2219 - Support block;

[0111] 2220 - Shaft mounting hole;

[0112] 2210A - Open-structure iron core lamination; 2210B - Closed-structure iron core lamination;

[0113] 2300 - Shaft; 2300A - Shaft; 2300B - Shaft;

[0114] 2310 - Shaft-shaped part;

[0115] 2320 - Toothed portion; 2321 - Meshing area; 2322 - Non-meshing area; 2323 - Partition groove; 2324 - Groove; 2345 - Induction magnet; 2346 - Inner conical surface;

[0116] 2340 - Rotor connection part;

[0117] 2350 - Power output end;

[0118] 2360 - Resolver mounting end; 2361 - Third fixing structure;

[0119] 2370 - Rotor connection end;

[0120] 2380 - Power Take-Off Unit;

[0121] 3000-Rotary Transformer;

[0122] 3100 - Rotor stator; 3120 - Annular groove;

[0123] 3200-Resolver Rotor;

[0124] 4000 - First-stage drive wheel set;

[0125] 4100 - First-stage transmission gear;

[0126] 4110 - Outer ring teeth;

[0127] 4120 - Center insert; 4121 - Reinforcing tooth;

[0128] 4200 - First-stage transmission gear shaft;

[0129] 4210 - Input terminal;

[0130] 4220 - Output teeth;

[0131] 4230 - Support shaft;

[0132] 4240 - First needle roller bearing;

[0133] 5000-Secondary drive wheel set;

[0134] 5100 - Secondary transmission large gear;

[0135] 5200 - Secondary transmission pinion; 5210 - Fourth ball bearing;

[0136] 6000-Central shaft transmission mechanism;

[0137] 6001 - Second needle roller bearing; 6002 - Third needle roller bearing; 6003 - Third ball bearing;

[0138] 6100 - Central Axis;

[0139] 6200 - Crank plate positioning sleeve; 6210 - Annular stepped structure;

[0140] 6300 Torque Sensor;

[0141] 6400 - Central shaft gear; 6410 - Gear section; 6420 - Support section; 6430 - Transmission section;

[0142] 6500 - First Unidirectional Transistor;

[0143] 6600 - Second Unidirectional Transistor;

[0144] 6700-tooth disc connection structure;

[0145] 7100 - Circuit board; 7110 - Sensing element;

[0146] 7200 - Bearing bracket. Detailed Implementation

[0147] To make the above-mentioned objects, features, and advantages of the present invention more apparent and understandable, specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings. Many specific details are set forth in the following description to provide a thorough understanding of the present invention. However, the present invention can be practiced in many other ways different from those described herein, and those skilled in the art can make similar modifications without departing from the spirit of the present invention. Therefore, the present invention is not limited to the specific embodiments disclosed below.

[0148] It should be noted that when a component is said to be "fixed to" another component, it can be directly attached to the other component or there may be an intervening component. When a component is said to be "connected to" another component, it can be directly connected to the other component or there may be an intervening component. The terms "vertical," "horizontal," "left," "right," and similar expressions used in this document are for illustrative purposes only.

[0149] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. The terminology used herein in the specification of this invention is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. The term "and / or" as used herein includes any and all combinations of one or more of the associated listed items.

[0150] The existing technology involves overlapping the notches of all the core laminations 2210 to form an axially arranged through-slot in the shaft mounting hole 2220 after stacking. Since the core laminations 2210 are stamped from the same die, if the stamping deformation of one notch differs from that of the other notches during the stamping process, the through-slot formed by the notch at the same location after multiple core laminations are stacked will have a different holding force on the shaft than other through-slots, which can easily cause the entire rotor core to vibrate.

[0151] like Figure 1-7As shown, this embodiment provides a rotor core including multiple sets of core laminations. Each set of core laminations includes at least one core lamination 2210. The number of core poles of the core lamination 2210 is N (N is an even number greater than 2). The shaft hole 2212 of the core lamination 2210 has M notches 2211, where M is not an integer multiple of N. After the multiple sets of core laminations 2210 are stacked to form a rotor core, the projections of the notches 2211 of at least one set of core laminations onto the plane of any core lamination 2210 do not overlap (or are at least partially offset). In this embodiment, by providing notches 2211 on the shaft hole 2212 of the core laminations 2210, the notches 2211 can be staggered axially on the shaft and stacked to be connected to the shaft by an interference fit. This allows defects caused by process reasons to be evenly distributed in the circumferential direction of the shaft, thereby avoiding the concentration of defects.

[0152] The rotor core provided by the present invention reduces or eliminates the problem of runout caused by the notch after the shaft is pressed into the rotor core by setting a notch on the shaft hole and arranging the notch in a staggered manner during the stacking process.

[0153] The angle difference between two adjacent sets of core laminations 2210 is K (i.e., the adjacent sets of core laminations are rotated by an angle K and then re-stacked), where K = 360*n / N, and n is a natural number less than N; the angle difference K ≠ 360*m / M (to avoid different gaps from overlapping after rotating through the angle K), and m is a natural number less than M, so that the gaps 2211 of multiple sets of core laminations are arranged in a spiral shape on the rotor core shaft mounting hole 2220.

[0154] Typically, the number of notches M should be much smaller than the number of core poles N, in order to reduce the number of notch openings and to ensure a sufficiently large contact area between the core laminations and the shaft.

[0155] Furthermore, when the iron core laminations are stacked using the rotary method of the present invention, the defect of excessive dynamic balance on one side caused by the unilateral offset of the iron core laminations during the stamping process can be overcome. The unilaterally offset iron core laminations are evenly distributed on the circumference, thereby keeping the dynamic balance in the circumferential direction of the iron core consistent, thus saving the debugging time of the production line dynamic balance.

[0156] Especially when the stamping of the core laminations results in one side being too large or too small, direct stacking will cause the entire rotor core to shift on one side, leading to excessive dynamic imbalance on one side and thus increasing the overall dynamic imbalance. The rotary stacking method of this invention ensures that each core lamination forms a certain angle with the previous one, and the defective parts will also shift. After one or more rotations, the defective parts will be evenly distributed on the circumference. This method ensures that the balance at every point along the circumference of the core is basically consistent, and the overall dynamic imbalance will be reduced.

[0157] Alternatively, M can be multiple, and the M notches are evenly distributed on the edge of the shaft hole 2212, so that when the core lamination is interference-fitted with the shaft, the contact area between the shaft hole of the core lamination and the shaft is equal at each position, and the stress in all directions is also equal.

[0158] The spiral shape includes at least one circumference, so that the notch 2211 can be evenly distributed on the circumference of the entire shaft, so that the notch 2211 is subjected to uniform force in all directions.

[0159] The spiral shape consists of an integer number of circumferences, that is, one, two or more circumferences, so that the notch 2211 can be evenly distributed on the circumference of the entire rotating shaft, and the notch 2211 is subjected to uniform force in all directions.

[0160] The notch 2211 can be triangular, arc-shaped, semi-circular, rectangular, or trapezoidal. It can also be any combination of the above shapes, or other irregular shapes not listed in the examples. To reduce stress concentration caused by the notch 2211, the notch can be designed with a rounded transition structure.

[0161] like Figure 7 As shown, the core lamination 2210 includes a core yoke 2213 and core teeth 2214 arranged in a circumferential array around the core yoke 2213. Each core tooth 2214 has pole shoes 2216 extending outwards at both ends of its outer edge, and a magnet mounting groove 2215 is formed between adjacent core teeth 2214. The core teeth 2214 are fan-shaped structures with a radius r1 smaller than the radius R of the core lamination. The centers of all the fan-shaped structures of the core teeth 2214 lie on the same circle centered on the axis of the rotor core, with a radius of r2, and satisfying R = r1 + r2. Specifically, the arrangement direction of each fan-shaped structure points outwards along the line connecting the center of the core lamination 2210 and the center of the core teeth 2214; and the midpoint of the arc of the fan-shaped structure is simultaneously located on the outer circle of the core lamination 2210. Designing the core teeth 2214 of the core lamination as an eccentric circle structure relative to the center of the entire core lamination can ensure that the waveform is closer to a sine wave and reduce harmonics.

[0162] The iron core tooth 2214 is connected to the iron core yoke 2213 via a magnetic shielding strip 2217. The width of the magnetic shielding strip 2217 is smaller than the minimum width of the iron core tooth 2214, and the magnetic shielding strip can effectively reduce magnetic leakage.

[0163] The fan-shaped surface of the iron core tooth section 2214 is provided with a circular hole 2218. The circular hole 2218 is equidistant from the three sides of the fan-shaped surface. Through the structural design of the circular hole 2218, the magnetic density can be ensured to be uniform.

[0164] The core laminations 2210 include open-structure core laminations 2210A and closed-structure core laminations 2210B, wherein the open-structure core laminations 2210A are arranged between the closed-structure core laminations 2210B; wherein, in the closed-structure core laminations 2210B, the pole shoes 2216 of two adjacent core teeth 2214 are connected to form a closed structure. Through the spacing design between the closed-structure core laminations 2210B and the open-structure core laminations 2210A, the structural strength of the entire rotor core can be increased. Figure 1-2 As shown, the closed-structure core laminations 2210B are arranged in pairs at both ends and in the middle of the rotor core; the open-structure core laminations 2210A are arranged in sets of 14 pieces between the closed-structure core laminations 2210B. In practice, the ratio of open-structure core laminations 2210A to closed-structure core laminations 2210B is not limited to this; those skilled in the art can increase or decrease the ratio as needed.

[0165] The closed-structure iron core lamination 2210B has a support block 2219 in the iron core yoke 2213 between two adjacent magnetic strips 2217 to position the short side of the magnet and reduce magnetic leakage. The support block 2219 can position and fix the magnet. Specifically, after the magnet is pressed into the magnet mounting groove 2215, the support block 2219 deforms to a certain extent and presses against the side of the magnet, so that the magnet and the magnet mounting groove 2215 form an interference fit in the radial direction. The magnet is tightly pressed against the outer edge or limiting structure of the magnet mounting groove 2215, which effectively reduces the unbalanced changes caused by magnet displacement and the resulting vibration and noise.

[0166] Due to the alternating structure design of the closed-structure iron core laminations 2210B and 2210A, support blocks 2219 are periodically arranged on the radially inner side of the magnet mounting slot 2215 of the rotor core formed by the alternating stacking of the closed-structure iron core laminations 2210B and 2210A. That is, on any iron core lamination 2210, the support blocks 2219 are periodically distributed relative to the center of the iron core lamination 2210. After multiple iron core laminations 2210 are stacked to form the rotor core, the support blocks 2219 are distributed axially throughout the rotor core in an alternating manner, and the spacing of the support blocks 2219 in any magnet mounting slot 2215 is random.

[0167] like Figure 8-12 As shown, this embodiment also provides a rotor, including a shaft 2300 and a rotor core 2200 provided in the above embodiments. The shaft 2300 is connected to the shaft mounting hole 2220 of the rotor core 2200 by an interference fit. In this embodiment, the shaft 2300 can be a commonly used rotor output shaft (i.e., the output end of the shaft is also shaft-shaped) or a rotor gear shaft (i.e., the output end of the shaft is machined with tooth surfaces to mesh with gears).

[0168] The rotor provided by the present invention has a shaft 2300 connected to a rotor core 2200 by an interference fit. The notch arrangement of the core laminations 2210 on the rotor core 2200 reduces or eliminates the problem of the shaft pressing into the rotor core due to the consistent position of the notches.

[0169] Furthermore, when the iron core laminations are stacked using the rotary method of the present invention, the defect of excessive dynamic balance on one side caused by the unilateral offset of the iron core laminations during the stamping process can be overcome. The unilaterally offset iron core laminations are evenly distributed on the circumference, thereby keeping the dynamic balance in the circumferential direction of the iron core consistent, thus saving the debugging time of the production line dynamic balance.

[0170] In this embodiment, optionally, when the rotating shaft 2300 is a rotor gear shaft, the rotating shaft 2300 includes a shaft-shaped portion 2310 and a tooth-shaped portion 2320. The shaft-shaped portion 2310 is connected to the rotor core 2200 by an interference fit. The surface of the tooth-shaped portion 2320 is machined to extend to the end tooth surface. The tooth-shaped portion 2320 includes a meshing area 2321 and a non-meshing area 2322. The meshing area 2321 is connected to the shaft-shaped portion 2310. The meshing area 2321 is used to mesh with the transmission gear, thereby outputting the power of the rotor. The non-meshing area 2322 is located at the free end of the rotating shaft 2300. A ring-cut partition groove 2323 is provided on the tooth surface at the junction of the meshing area 2321 and the non-meshing area 2322. The tooth surface can be a helical tooth or a straight tooth. By designing the partition groove 2323, when the toothed portion 2310 of the rotating shaft 2300 is pressed into the rotating shaft mounting hole 2220 of the rotor core 2200, the non-meshing area 2322 bears the impact force, and the deformation of the tooth surface is not transmitted to the meshing area 2321, thereby ensuring that the tooth profile of the meshing area 2321 remains unchanged. Those skilled in the art will understand that the partition groove 2323 can also be provided in the non-meshing area 2322, thereby retaining a portion of the non-meshing area on the outer side of the meshing area 2321, which can better mesh with the transmission gear.

[0171] When the shaft 2300 is pressed into the shaft mounting hole 2220 of the rotor core 2200 provided in the above embodiment, the notches 2211 of the core laminations 2210 of the rotor core 2200 are staggered, resulting in a greater pressing force between the shaft 2300 and the shaft mounting hole 2220. Therefore, the design of the shaft 2300 with the partition groove 2323 can better ensure that the tooth profile of the meshing area 2321 remains unchanged. Because the rotor core misalignment notch scheme of the above embodiment results in a larger pressing area (in the traditional rotor core, the notch does not contact the shaft during pressing), the pressing force of the shaft 2300 when pressing into the rotor core is also greater. Therefore, when the pressing force is applied to the end of the shaft 2300, the tooth profile change at the end of the shaft 2300 will inevitably be greater. By adopting the partition groove 2323 structure design in this embodiment, the pressing force on the tooth surface inside the partition groove 2323 is smaller or the transmission of the pressing force on the tooth surface can be completely blocked. This ensures that the tooth surface deformation is smaller or non-deformed during the pressing of the shaft 2300 into the rotor core.

[0172] Those skilled in the art will recognize that when the rotor core 2200 structure and the partition slot 2323 structure provided in the above embodiments are used simultaneously, the partition slot 2323 can significantly reduce the deformation of the tooth surface when the shaft 2300 is pressed into the rotor core 2200 structure, thus providing a better effect on the increased pressing force caused by the misaligned arrangement of the notch in the rotor core 2200. However, when the rotor core 2200 adopts a conventional structural design (the notch is arranged linearly along the axial direction), it can also effectively reduce the impact of the pressing force on the tooth surface deformation.

[0173] The depth of the partition groove 2323 does not exceed the height of the tooth surface, thus ensuring good mechanical strength of the rotating shaft 2300 at the tooth profile 2320. If the depth of the partition groove 2323 exceeds the height of the tooth surface, it means that the depth of the partition groove 2323 must extend into the root circle of the tooth. Therefore, the bottom surface of the partition groove 2323 should be higher than the circumference of the root circle. Preferably, the depth of the partition groove can be less than half the height of the tooth surface. This ensures that the pressing force on the rotating shaft 2300 can be better transmitted to the shaft profile 2310, and minimizes tooth surface deformation during transmission.

[0174] The length between the partition groove 2323 and the end of the rotating shaft 2300 does not exceed one-third of the tooth surface length, thereby optimizing the structural layout design of the rotating shaft 2300.

[0175] This embodiment can optionally, such as Figure 11 As shown, a groove 2324 is provided on the end face of the rotating shaft 2300 at one end of the shaft-shaped part 2310. An induction magnet 2345 is installed in the groove 2324. By placing the induction magnet 2345 in the groove 2324, the structure of the rotating shaft 2300 can be utilized more rationally. On the one hand, it can ensure that the pressing force on the rotating shaft 2300 can be better transmitted to the shaft-shaped part 2310. On the other hand, it can minimize the deformation of the tooth surface caused during the transmission process. Furthermore, it can also fix the induction magnet 2345.

[0176] When the end face of the shaft 2300 is provided with a groove 2324, the force-bearing area of ​​the end face of the shaft 2300 is greatly reduced, which makes the deformation of the tooth surface more significant when the pressing force is applied to the end face of the shaft 2300. Since conventional tooth surfaces are continuous, the continuous transmission of tooth surface deformation leads to deformation of the tooth surface at the meshing part, thereby increasing the meshing wear of the entire shaft during the meshing process with the transmission gear. In this case, the design of the partition groove 2323 can better solve this technical problem.

[0177] The groove 2324 is circular, and an inner conical surface 2346 is provided at the center of the groove 2324. Correspondingly, the induction magnet 2345 is also circular, and the shape of the induction magnet 2345 is adapted to the groove 2324 so that the induction magnet 2345 can be inserted into the groove 2324. At this time, the depth of the groove 2324 should be greater than or equal to the height of the induction magnet 2345, so that after the induction magnet 2345 is inserted into the groove 2324, it can be embedded inside the groove 2324, preventing the induction magnet 2345 from being exposed, thereby protecting the induction magnet 2345.

[0178] The diameter of the groove 2324 is smaller than the diameter of the root circle of the tooth surface, thereby avoiding the groove 2324 being too large and causing the area for transmitting the pressing force inside the root circle to be too small, and ensuring the protection of the induction magnet 2345 after it is installed.

[0179] The induction magnet 2345 is also circular, and the diameter of the induction magnet 2345 is slightly larger than the diameter of the groove 2324, so that the induction magnet 2345 is installed in the groove 2324 by interference fit; or, those skilled in the art may choose to connect the induction magnet 2345 in the groove 2324 by adhesive.

[0180] When the induction magnet 2345 is connected in the groove 2324 by an interference fit, it will inevitably cause deformation of the tooth surface around the groove. Therefore, the design of the partition groove 2323 in the technical solution of the present invention can perfectly solve the problem of tooth surface deformation being transmitted to the meshing area 2321, thereby ensuring that the tooth profile of the meshing area 2321 remains unchanged and ensuring the service life of the rotating shaft 2300.

[0181] This embodiment also provides a method for forming a rotor core, including:

[0182] Iron core laminations 2210 are provided and grouped, each group of iron core laminations includes at least one iron core lamination 2210, and at least one iron core lamination 2210 in each group of iron core laminations has a notch 2211 on the circumference of the shaft hole;

[0183] The iron core laminations 2210 are stacked to form the rotor iron core 2200, so that there is a deflection angle of 360*n / N between the gaps of two adjacent sets of iron core laminations 2210, where n is a natural number less than N.

[0184] The rotor core forming method provided by the present invention uses a rotary stacking forming process to form notches 2211 in a spiral arrangement on the shaft mounting hole 2220. The notches 2211 are evenly distributed on the circumference, thereby overcoming the defect of excessive dynamic balance on one side due to unilateral offset of the core laminations 2210 during the stamping process. The unilaterally offset core laminations 2210 are evenly distributed on the circumference, thereby keeping the dynamic balance in the circumferential direction of the core consistent, thus saving the adjustment time of dynamic balance on the production line.

[0185] When there are multiple notches M, the notches are evenly distributed around the shaft hole of the iron core lamination. At this time, the deflection angle 360*n / N≠360*m / M (m is a natural number less than M) so that the notches form M spiral shapes in the shaft mounting hole.

[0186] This embodiment also provides a rotor, including a shaft 2300 and a rotor core 2200 manufactured by the forming method provided in the above embodiments. The shaft 2300 is connected to the shaft mounting hole 2220 of the rotor core 2200 by an interference fit.

[0187] The rotor provided by the present invention reduces or eliminates the rotor runout problem caused by the notch 2211 on the shaft hole of the iron core lamination 2210 and the notch is misaligned during the stacking and forming of the iron core lamination.

[0188] Furthermore, when the iron core laminations are stacked using the rotary method of the present invention, the defect of excessive dynamic balance on one side caused by the unilateral offset of the iron core laminations during the stamping process can be overcome. The unilaterally offset iron core laminations are evenly distributed on the circumference, thereby keeping the dynamic balance in the circumferential direction of the iron core consistent, thus saving the debugging time of the production line dynamic balance.

[0189] This embodiment also provides an electric motor, including the rotor core or rotor provided in the above embodiments.

[0190] This embodiment also provides a mid-drive motor, including the rotor core or rotor provided in the above embodiments.

[0191] The motor and mid-drive motor provided by this invention use a rotor core 2200 with misaligned notches, thereby reducing or eliminating the runout problem caused by the shaft pressing into the rotor core due to the consistent position of the notches, making the motor and mid-drive motor rotate more smoothly. Furthermore, the design of the partition groove 2323 greatly reduces or even completely eliminates the pressing force, while overcoming the problems of reduced force-bearing area on the shaft end face caused by the groove 2324 and tooth surface deformation caused by the use of interference fit connection of the induction magnet 2345.

[0192] Combination Figure 25 As shown, this embodiment of the invention also provides a detection system, including a circuit board 7100, a sensing element 7110, and a rotating shaft 2300 provided in the above embodiments. The tooth surface of the rotating shaft 2300 is provided with a partition groove 2323, and the end face of the rotating shaft 2300 has a groove 2324. A sensing magnet 2345 is provided in the groove 2324. The position of the sensing element 7110 corresponds to the position of the sensing magnet 2345. The sensing element 7110 is connected to the circuit board 7100 and sends the sensing signal to the circuit board 7100.

[0193] The detection system provided in this embodiment can overcome the deformation of the shaft and tooth surface caused by the concentrated pressing force on the end face of the shaft 2300 due to the installation of the induction magnet 2345. This makes the positional correspondence between the induction magnet 2345 and the sensing element 7110 more accurate, thereby improving the detection effect of the detection system.

[0194] In this embodiment, the center of the sensing element 7110 and the sensing magnet 2345 are located on the same axis, thereby improving the detection effect of the sensing element 7110 on the sensing magnet 2345.

[0195] In this embodiment, the sensing element 7110 is a magnetically encoded chip. Those skilled in the art will understand that the sensing element 7110 can also be any other element capable of performing the same function as the magnetically encoded chip.

[0196] Combination Figure 24-26 This embodiment also provides a mid-drive motor transmission system, including a primary drive gear set 4000 and a rotating shaft 2300 provided in the above embodiments. The primary drive gear set 4000 includes a primary drive gear 4100, which meshes with the meshing area 2321 of the rotating shaft 2300. In the transmission system provided in this embodiment, because the rotating shaft 2300 is provided with a partition groove 2323, after the rotating shaft 2300 is pressed into the rotor core 2200, the tooth surface of the meshing area 2321 on the rotating shaft 2300 will not deform or significantly reduce the deformation range due to the pressing force. Therefore, during the meshing process of the drive shaft 2300 and the primary drive gear 4100, the transmission effect between them is better, and they will not be damaged by mutual meshing due to tooth surface deformation, ensuring the transmission effect and the service life of the rotating shaft 2300 and the primary drive gear 4100.

[0197] Combination Figures 13-17In the transmission system provided in this embodiment, the primary transmission gear 4100 includes a central insert 4120 and an outer ring tooth portion 4110. The central insert 4120 has a shaft hole at its center. The outer ring tooth portion 4110 is connected to the outer circumference of the central insert 4120 and arranged coaxially. The axial width of the outer ring tooth portion 4110 is greater than the axial width of the central insert 4120, and both ends of the outer ring tooth portion 4110 extend beyond the central insert 4120 in the axial direction. The central insert 4120 is made of metal, and the outer ring tooth portion 4110 is made of non-metallic material. The transmission system provided in this embodiment uses a rotating shaft 2300 to directly drive the primary transmission gear 4100. The rotating shaft 2300 rotates at high speeds, and the primary transmission gear 4100, made of a single metal material, has a large moment of inertia, resulting in energy loss. Conversely, a primary transmission gear 4100 made of non-metallic materials faces problems such as high contact surface stress and insufficient support strength to meet transmission requirements. Therefore, this embodiment uses a central insert 4120 made of metallic material and an outer ring tooth portion 4110 made of non-metallic material. The width of the outer ring tooth portion 4110 is greater than that of the central insert 4120. This ensures a larger contact area between the outer ring tooth portion 4110 and the rotating shaft 2300, reducing contact stress on the outer ring tooth portion 4110. It also lowers the overall moment of inertia of the central insert 4120 and the outer ring tooth portion 4110, reducing energy loss during transmission. Furthermore, the smaller size of the metallic central insert 4120 allows it to meet the transmission torque requirements.

[0198] Combination Figure 17 In the transmission system provided in this embodiment, the outer circumferential surface of the central insert 4120 is provided with a reinforcing structure; the reinforcing structure protrudes or is recessed into the outer circumferential surface. The design of the reinforcing structure can effectively increase the connection area between the central insert 4120 and the outer ring tooth 4110, thereby making the engagement between the central insert 4120 and the tooth 4110 more stable and maintaining the overall shape during transmission; especially when the width of the central insert 4120 is reduced, the reinforcing structure can compensate for the problem of reduced connection area.

[0199] In the transmission system provided in this embodiment, the reinforcing structure consists of reinforcing teeth 4121, knurling, or splines arranged around the outer circumference of the central insert 4120.

[0200] In the transmission system provided in this embodiment, the reinforcing tooth 4121 is divided into at least three segments in the axial direction. This design not only further increases the connection area between the outer ring tooth portion 4110 and the central insert 4120, but also overcomes the axial stress during transmission, maintaining the structural stability of the central insert 4120 and the outer ring tooth portion 4110 during transmission.

[0201] The top surface of the reinforcing tooth 4121 is an arc surface or a surface with an obtuse angle. In this embodiment, the protruding top cannot be made into a sharp corner, and the width of the top is not less than 0.2mm to avoid stress concentration during injection molding and to prevent the sharp corner from breaking when subjected to high torque.

[0202] In the transmission system provided in this embodiment, when a spline is used between the central insert 4120 and the outer ring tooth 4110, the number of splines is not less than 4 and the spline module is not less than 0.25.

[0203] In the transmission system provided in this embodiment, the outer ring tooth 4110 is injection molded on the outer circumference of the central insert 4120, which can make the connection between the central insert 4120 and the outer ring tooth 4110 tighter, so that it is not easy to deform during transmission.

[0204] Combination Figures 13-17 , Figures 24-26 , Figures 37-39 In the transmission system provided in this embodiment, the primary transmission wheel set 4000 also includes a primary transmission gear shaft 4200, which is coaxially connected to the primary transmission gear 4100.

[0205] Combination Figure 18 and Figure 28 In the transmission system provided in this embodiment, the primary transmission gear shaft 4200 includes an input end 4210, an output tooth portion 4220, and a support shaft 4230. The input end 4210 is connected to the central insert 4120, the output tooth portion 4220 is located between the input end 4210 and the support shaft 4230, the diameter of the support shaft 4230 is smaller than the diameter of the output tooth portion 4220 and the input end 4210, the support shaft 4230 is connected to the first needle roller bearing 4240, and the outer diameter of the first needle roller bearing 4240 is smaller than the tip circle diameter of the output tooth portion 4220. The transmission system provided in this embodiment has a support shaft 4230 designed at the end of the primary transmission gear shaft 4200. The support shaft 4230 has a smaller diameter, and a needle roller bearing with a relatively small diameter is connected to the support shaft 4230. The needle roller bearing supports the transmission end of the primary transmission gear shaft 4200, thereby overcoming the problem of severe unilateral wear caused by the primary transmission gear shaft 4200 being in a suspended state during transmission. This ensures more stable transmission of the transmission system and reduces the problem of unilateral wear of the primary transmission gear shaft during transmission.

[0206] In the transmission system provided in this embodiment, such as Figure 18As shown, the input end 4210 and the central insert 4120 are connected by a spline arranged on the surface of the input end 4210, thereby making the circumferential bonding force between the central insert 4120 and the outer ring tooth portion 4110 more uniform and the coaxiality better. Those skilled in the art will know that a keyway can also be used instead of a spline connection.

[0207] In the transmission system provided in this embodiment, combined with Figure 14 and Figure 18 Bearings are respectively provided on the input ends 4210 on both sides of the central insert 4120, and the bearings are at least partially located inside the outer ring tooth portion 4110. In this case, the outer diameter of the bearing should be smaller than the inner diameter of the outer ring tooth portion 4110. The arrangement on both sides of the central insert 4120 makes the support of the central insert 4120 for the outer ring tooth portion 4110 more stable. Simultaneously, in conjunction with the needle roller bearing on the support shaft 4230, the entire first-stage transmission gear shaft 4200 can be well supported at both ends and in the middle, preventing the first-stage transmission gear shaft 4200 from being suspended and causing unilateral wear during transmission. The overall structural layout of the outer ring tooth portion 4110, the central insert 4120, and the bearings on both sides allows for more rational use of the transmission space, ensures transmission stability, and extends the service life of the first-stage transmission gear shaft 4200.

[0208] like Figure 24 As shown, the transmission system provided in this embodiment also includes a secondary transmission gear set 5000 and a central shaft transmission mechanism 6000. The secondary transmission gear set 5000 includes a secondary transmission large gear 5100 and a secondary transmission small gear 5200 coaxially connected. The secondary transmission large gear 5100 meshes with the primary transmission gear shaft 4200, and the secondary transmission small gear 5200 meshes with the central shaft transmission mechanism 6000. The secondary transmission small gear 5200 is located on the side away from the primary transmission gear shaft 4200, so that its radial position corresponds to that of the first needle roller bearing 4240. Because the first needle roller bearing 4240 has a small radial dimension, it can be reasonably arranged next to the secondary transmission small gear 5200. By setting a support shaft 4230 on the outside of the primary transmission gear shaft 4200 and supporting it with a needle roller bearing, the radial force caused by the meshing of the primary transmission gear shaft 4200 with the secondary transmission large gear 5100 is overcome. This prevents the primary transmission gear shaft 4200 from tilting, shifting, or running during transmission, and avoids wear on the tooth surface of the primary transmission gear shaft 4200 during meshing. This ensures the stable and reliable operation of the gear system and meets the design requirements for service life.

[0209] Further integration Figures 37-39As shown, in the transmission system provided in this embodiment, the primary transmission gear shaft 4200 passes through the bearing bracket 7200, and the support shaft 4230 is installed in the first bearing mounting hole 1310 on the inner wall of the main cover 1300 through the first needle roller bearing 4240. The first bearing mounting hole 1310 on the inner wall of the main cover 1300 provides fixed support for the first needle roller bearing 4240, thereby achieving stable transmission.

[0210] A bearing bracket 7200 connects between the main housing 1000 and the main cover 1300, forming a reduction chamber to house the primary transmission gear set 4000 and the secondary transmission gear set 5000. Specifically, the bearing bracket 7200 and the main housing 1000 form a chamber to accommodate the primary transmission gear set 4000, and the bearing bracket 7200 and the main cover 1300 form a chamber to accommodate the secondary transmission gear set 5000. The two chambers are connected at the point where the primary transmission gear shaft 4240 passes through the bearing bracket 7200, forming the reduction chamber. The reduction chamber accommodates the primary transmission gear set 4000 and the secondary transmission gear set 5000, thus preventing the splashing of lubricating oil and wear debris during transmission, and also preventing dust from entering the reduction chamber, thereby ensuring the stable and reliable operation of the gear system and meeting the design requirements for service life.

[0211] The inner wall of the main cover 1300 is also provided with a second bearing mounting hole 1320. The shaft of the secondary transmission pinion 5200 is mounted in the second bearing mounting hole 1320 through a fourth ball bearing 5210. The first bearing mounting hole 1310 is tangent to the second bearing mounting hole 1320 or communicates with it on the side wall. After the second bearing mounting hole 1320 is opened on the side wall of the main cover 1300 and the fourth ball bearing 5210 is installed in the second bearing mounting hole 1320, there is no longer enough space on the side wall of the main cover 1300 to support and fix the end of the commonly used primary transmission gear shaft 4200. Therefore, in this embodiment, a support shaft 4230 with a smaller diameter than the output tooth 4220 is further designed at the end of the primary transmission gear shaft 4200. Even after the first needle roller bearing 4240 is installed on the support shaft 4230, the maximum outer diameter of the first needle roller bearing 4240 is basically equal to or even smaller than the size of the output tooth 4220. This allows the support shaft 4230 to support the primary transmission gear shaft 4200, thereby ensuring the stable and reliable operation of the gear system and meeting the design requirements for service life.

[0212] Further integration Figure 40 As shown, in the transmission system provided in this embodiment, the rotation axis distance Z between the first-stage transmission gear set 4000 and the second-stage transmission wheel set 5000 is 10-20mm, preferably 15.3mm, and the diameter of the first needle roller bearing 4240 is 5-10.5mm, preferably 8mm.

[0213] Combination Figure 20 , Figure 21 As shown, in the transmission system provided in this embodiment,

[0214] The central shaft transmission mechanism 6000 includes a central shaft 6100, a torque sensor 6300, a gear positioning sleeve 6200, a central shaft gear 6400, a first one-way valve 6500, and a second one-way valve 6600, etc., wherein:

[0215] The bottom bracket 6100 is connected to the crank and pedal at both ends respectively. It can receive power input through the crank structure at both ends and transmit it to the chainring positioning sleeve 6200 through the torque sensor 6300, and then to the chainring on the chainring positioning sleeve 6200, which drives the rear axle to rotate and thus drives the bicycle forward.

[0216] Torque sensor 6300 is fixedly installed on central shaft 6100. Torque sensor 6300 can sense the torque signal transmitted from central shaft 6100 to crank positioning sleeve 6200 and send it to controller. The controller controls the output power of motor assembly 2000 in central motor according to the magnitude of the sensed signal.

[0217] The chainring positioning sleeve 6200 is connected to the torque sensor at one end via the first one-way valve 6500, and fixedly connected to the chainring at the other end. The first one-way valve 6500 enables the clutch transmission between the chainring positioning sleeve 6200 and the torque sensor 6300, preventing the transmission system of the mid-drive motor from continuing to rotate due to rotational inertia when the mid-axle 6100 stops rotating due to the rider's control, thus protecting the rider's safety.

[0218] The bottom bracket gear 6400 is connected to the chainring positioning sleeve via the second one-way actuator 6600. The bottom bracket gear 6400 meshes with the secondary transmission pinion 5200. The second one-way actuator 6600 enables the clutch transmission between the chainring positioning sleeve 6200 and the bottom bracket gear 6400. When the mid-drive motor cannot provide power assistance due to power failure, battery depletion, transmission failure, or human operation (such as manually turning off the mid-drive motor or changing the assist mode of the mid-drive motor), the rider can continue riding. During riding, the second one-way actuator 6600 disengages the bottom bracket 6100, chainring positioning sleeve 6200, and transmission gear structure of the transmission system. This avoids damage to the transmission system and reduces the rider's riding pressure and burden by no longer engaging any transmission gears in the reverse direction during riding, making riding more effortless.

[0219] Those skilled in the art will understand that when the primary transmission gear set 4000 and the secondary transmission gear set 5000 are not used in the transmission system, the central shaft gear 6400 can also be directly driven by the motor assembly 2000. That is, when the transmission system provided in this embodiment is adjusted from a three-stage transmission to a single-stage transmission, the central shaft can still be driven, and the transmission requirements of the mid-mounted motor can be met. Similarly, those skilled in the art can also adjust the transmission system provided in this embodiment from a three-stage transmission to a two-stage or four-stage transmission, etc.

[0220] The transmission system provided in this embodiment can solve the problem that when the mid-drive motor cannot assist forward movement due to reasons such as power failure, power depletion, transmission failure, or human operation (such as manually turning off the mid-drive motor or changing the assist mode of the mid-drive motor), the rider can continue riding. During the riding process, the second one-way device 6600 disengages the bottom bracket 6100 and the chainring positioning sleeve 6200 from the transmission gear structure of the transmission system. On the one hand, this can avoid damage to the transmission system. On the other hand, since no reverse drive is performed on any transmission gears of the transmission system during the riding process, the riding pressure and burden on the rider can be reduced, making riding more effortless.

[0221] like Figure 22 , Figure 23 As shown, in the transmission system provided in this embodiment, the central shaft gear includes a gear section 6410, a support section 6420, and a transmission section 6430, wherein:

[0222] The gear section 6410 is located on the outside and is used for meshing and transmission with other gears (such as the secondary transmission large gear 5100);

[0223] The support part 6420 is located on the inner side of the gear part 6410 in the radial direction and is used to connect with the gear positioning sleeve 6200 via the third ball bearing 6003. The support part 6420 can provide stable support for the gear part 6410 and ensure the stable transmission of the gear part 6410.

[0224] The transmission unit 6430 is located on one side of the support unit 6420 in the axial direction and is used to connect with the crankcase positioning sleeve 6200 through the second one-way device 6600. Under the action of the second one-way device 6600, the transmission unit 6430 realizes the engagement and disengagement of the gear 6410 and the crankcase positioning sleeve 6200.

[0225] The transmission system provided in this embodiment improves the structure of the central shaft gear, making it significantly different from the conventional gear structure. It also separates the force-bearing function of the support part from the transmission function of the transmission part, avoiding the second one-way device from directly bearing the force to support the transmission.

[0226] Further integration Figure 21In the transmission system provided in this embodiment, the gear part 6410, the support part 6420, and the transmission part 6430 form an L-shaped layout. In the axial direction, the transmission part 6430 is located outside the support part 6420 and is structurally closer to the position of the crankcase connection structure 6700, while the support part 6420 is closer to the position of the annular step structure 6210 of the crankcase positioning sleeve 6200. This makes the structural layout reasonable and the power transmission is closer to the position of the crankcase, making the power transmission more stable.

[0227] The toothed plate positioning sleeve 6200 is provided with an annular step structure 6210, wherein the first one-way device 6500 is disposed in the annular step structure 6210, the second one-way device 6600 is close to the annular step structure 6210, and the outer diameter of the transmission part 6430 does not exceed the outer diameter of the annular step structure 6210; thus, the overall structure layout is reasonable and compact, and occupies little space.

[0228] The crankcase positioning sleeve 6200 is connected to the central shaft 6100 through two needle roller bearings, and the two needle roller bearings are located on both sides of the support. The needle roller bearings themselves have smaller structural dimensions, thereby reducing the size requirements of the crankcase positioning sleeve 6200. At the same time, the arrangement of the two needle roller bearings on both sides of the support 6420 can provide more stable support for the support 6420.

[0229] The two needle roller bearings are a second needle roller bearing 6001 and a third needle roller bearing 6002, with the second needle roller bearing 6001 located outside the third needle roller bearing 6002. The third needle roller bearing 6002 is connected to the torque sensor 6300. Correspondingly, the connection position of the torque sensor 6300 is also set in a stepped shape, which can make the structure more compact.

[0230] The inner diameter of the third needle roller bearing 6002 is larger than that of the second needle roller bearing 6001, which makes the assembly of the entire transmission system more convenient and allows for assembly in the direction of increasing size.

[0231] The torque sensor 6300 is fixedly connected to the central shaft 6100 via a spline; the central shaft 6100 is a hollow tube shaft, and its two ends are respectively connected to a crank.

[0232] like Figures 27-29 As shown, an embodiment of the present invention also provides a mid-drive motor, including a rotor core 2200, a rotating shaft 2300, a rotor, a primary transmission gear 4100, a primary transmission gear shaft 4200 or a central shaft transmission mechanism 6000 or a transmission system provided in the above embodiments, wherein the rotating shaft 2300 is mounted on the rotor core 2200.

[0233] The mid-drive motor provided in this embodiment uses a rotor core 2200 with misaligned notches, which reduces or eliminates the runout problem caused by the shaft pressing into the rotor core due to the consistent notch positions. This makes the motor and the mid-drive motor rotate more smoothly. Furthermore, the design of the partition slot greatly reduces or even completely eliminates the pressing force, while overcoming the problems of reduced force area on the shaft end face caused by the groove and tooth surface deformation caused by the use of interference fit induction magnets.

[0234] The mid-drive motor provided in this embodiment, due to the partition groove design of the shaft 2300, ensures that when the toothed portion of the shaft is pressed into the shaft mounting hole of the rotor core, the non-meshing area bears the impact force, and the deformation of the tooth surface is not transmitted to the meshing area, thus ensuring that the tooth profile in the meshing area remains unchanged. At the same time, the shaft provided by this invention also overcomes the problems of reduced force-bearing area on the shaft end face caused by grooves and tooth surface deformation caused by the use of interference-fit induction magnets.

[0235] The mid-drive motor provided in this embodiment has a rotor shaft 2300 connected to the rotor core 2200 by an interference fit. The notch arrangement of the core laminations 2210 on the rotor core 2200 reduces or eliminates the runout problem caused by the shaft being pressed into the rotor core due to the consistent position of the notches.

[0236] The mid-drive motor provided in this embodiment has a support shaft 4230 designed at the end of the primary drive gear shaft 4200. The support shaft 4230 has a smaller diameter, and a needle roller bearing with a relatively small diameter is connected to the support shaft 4230. The needle roller bearing supports the transmission end of the primary drive gear shaft 4200, thereby overcoming the problem of severe unilateral wear caused by the primary drive gear shaft 4200 being in a suspended state during transmission. This ensures more stable transmission of the transmission system and reduces the problem of unilateral wear of the primary drive gear shaft during transmission.

[0237] The mid-drive motor provided in this embodiment uses a rotating shaft 2300 to directly drive the primary transmission gear 4100. The rotating shaft 2300 rotates at high speeds, and the primary transmission gear 4100, made of a single metal material, has a large moment of inertia, resulting in energy loss. Conversely, a primary transmission gear 4100 made of non-metallic materials faces problems such as high contact surface stress and insufficient support strength to meet transmission requirements. Therefore, this embodiment uses a central insert 4120 made of metallic material and an outer ring tooth portion 4110 made of non-metallic material. The width of the outer ring tooth portion 4110 is greater than that of the central insert 4120. This ensures a larger contact area between the outer ring tooth portion 4110 and the rotating shaft 2300, reducing contact stress on the outer ring tooth portion 4110. It also lowers the overall moment of inertia of the central insert 4120 and the outer ring tooth portion 4110, reducing energy loss during transmission. Furthermore, the smaller size of the metallic central insert 4120 allows it to meet the transmission torque requirements.

[0238] This embodiment also provides an electric bicycle, including the shaft 2300 provided in the above embodiments, or the detection system provided in the above embodiments, or the transmission system provided in the above embodiments, or the mid-mounted motor provided in the above embodiments, and the corresponding beneficial effects will not be elaborated further.

[0239] like Figure 30-32 As shown, this embodiment of the invention also provides a mid-drive motor using a rotary transformer, including a motor assembly 2000, a main housing 1000, a transition housing 1200, a motor cover 1100, and a rotary transformer 3000, wherein:

[0240] The motor assembly 2000 includes a stator 2100, a rotor, and a shaft 2300A. The shaft 2300A includes a rotor connection portion 2340, a power output end 2350, and a resolver mounting end 2360. The rotor connection portion 2340 is located between the power output end 2350 and the resolver mounting end 2360. The rotor core 2200 of the rotor is connected to the rotor connection portion 2340.

[0241] The main housing 1000 is provided with a stator mounting part 1010 for accommodating the stator 2100. The stator mounting part 1010 is separated from the interior of the main housing 1000 by a partition 1020. The opening of the stator mounting part 1010 faces outward. The resolver mounting end 2360 of the rotating shaft 2300A extends outward from the opening of the stator mounting part 1010. The power output end 2350 of the rotating shaft 2300A extends inward through the partition 1020 and is located inside the main housing 1000.

[0242] The transition housing 1200 is connected to the opening of the stator mounting portion 1010 of the main housing 1000 to form the motor mounting cavity 1001. The transition housing 1200 is provided with a shaft hole 1210 that allows the rotating shaft to pass through, and the resolver mounting end 2360 is located outside the shaft hole 1210.

[0243] The motor cover 1100 is connected to the transition housing 1200 outside the shaft hole 1210 to form a resolver mounting cavity 1002 outside the shaft hole 1210 and to house the resolver mounting end 2360 therein;

[0244] The resolver 3000 is located in the resolver mounting cavity and includes a resolver stator 3100 and a resolver rotor 3200, wherein the resolver rotor 3200 is mounted on the resolver mounting end 2360.

[0245] The mid-drive motor provided in this embodiment uses a resolver 3000 to rotate synchronously under the drive of the rotor, thereby enabling real-time detection of the rotor's operating status and making the mid-drive motor's control of the motor assembly more accurate. The mid-drive motor provided in this embodiment forms a motor mounting cavity 1001 and a resolver mounting cavity 1002, independent of the internal transmission cavity 1003 of the motor housing 1000, through the docking of the main housing 1000, transition housing 1200, and motor cover 1100. This facilitates the assembly of the motor assembly 2000, the rotating shaft 2300A, and the resolver 3000. Furthermore, the transition housing 1200 isolates the motor mounting cavity 1001 and the resolver mounting cavity 1002 from each other, thus isolating the resolver 3000 and the motor assembly 2000 and preventing electromagnetic interference between them during rotation. In this embodiment, the mid-mounted motor is achieved by docking the main housing 1000 with the transition housing 1200, and then docking the transition housing 1200 with the motor cover 1100. The resolver mounting cavity 1002 is constructed by docking the transition housing 1200 with the motor cover 1100, which facilitates the fixing of the resolver stator 3100 on the transition housing 1200 or the motor cover 1100.

[0246] In this embodiment, the walls of the main housing 1000 and the transition housing 1200 are respectively provided with interconnected lead wire channels. The lead wire channels connect the resolver mounting cavity and the interior of the main housing. Wires are arranged in the lead wire channels to connect the resolver stator to the circuit board inside the main housing. The design structure of the lead wire channels ensures the safety requirements of the mid-drive motor.

[0247] This invention also provides a mid-drive motor using a rotary transformer, comprising a motor assembly 2000, a main housing 1000, a transition housing 1200, a motor cover 1100, and a rotary transformer 3000.

[0248] The motor assembly 2000 includes a stator 2100, a rotor, and a shaft 2300A. The shaft 2300A includes a rotor connection portion 2340, a power output end 2350, and a resolver mounting end 2360. The rotor connection portion 2340 is located between the power output end 2350 and the resolver mounting end 2360. The rotor core 2200 of the rotor is connected to the rotor connection portion 2340.

[0249] The main housing 1000 is provided with a stator mounting part 1010 for accommodating the stator 2100. The stator mounting part 1010 is separated from the interior of the main housing 1000 by a partition 1020. The opening of the stator mounting part 1010 faces outward. The resolver mounting end 2360 of the rotating shaft 2300A extends outward from the opening of the stator mounting part 1010. The power output end 2350 of the rotating shaft 2300A extends inward through the partition 1020 and is located inside the main housing 1000.

[0250] The transition housing 1200 is connected to the stator mounting portion 1010 of the main housing 1000 to form a motor mounting cavity 1001. The transition housing 1200 is provided with a shaft hole 1210 that allows the rotating shaft to pass through, and the resolver mounting end 2360 is located outside the shaft hole 1210.

[0251] The motor cover 1100 mates with the opening of the stator mounting portion 1010 of the main housing 1000 to form a resolver mounting cavity 1002 on the outside of the shaft hole 1210, and accommodates the resolver mounting end 2360 therein;

[0252] The resolver 3000 is located in the resolver mounting cavity and includes a resolver stator 3100 and a resolver rotor 3200, wherein the resolver rotor 3200 is mounted on the resolver mounting end 2360.

[0253] The mid-drive motor provided in this embodiment uses a resolver 3000 to rotate synchronously under the drive of the rotor, thereby enabling real-time detection of the rotor's operating status and making the mid-drive motor's control of the motor assembly more accurate. The mid-drive motor provided in this embodiment forms a motor mounting cavity 1001 and a resolver mounting cavity 1002, independent of the internal transmission cavity 1003 of the motor housing 1000, through the docking of the main housing 1000, transition housing 1200, and motor cover 1100. This facilitates the assembly of the motor assembly 2000, the rotating shaft 2300A, and the resolver 3000. Furthermore, the transition housing 1200 isolates the motor mounting cavity 1001 and the resolver mounting cavity 1002 from each other, thus isolating the resolver 3000 and the motor assembly 2000 and preventing electromagnetic interference between them during rotation. In this embodiment, the mid-mounted motor uses a docking method between the main housing 1000 and the motor cover 1100, and a transition housing 1200 is set inside to divide the chamber constructed by the main housing 1000 and the motor cover 1100 into independent resolver mounting chamber 1002 and motor mounting chamber 1001, which facilitates the fixing of resolver stator 3100 on the transition housing 1200 or the motor cover 1100.

[0254] In this embodiment, a lead wire channel is provided on the wall of the main housing 1000. The lead wire channel connects the resolver mounting cavity 1002 and the transmission cavity 1003 inside the main housing 1000. Wires are arranged in the lead wire channel to connect the resolver stator to the circuit board 7100 inside the main housing. The design structure of the lead wire channel ensures the safety requirements of the mid-drive motor.

[0255] The above embodiments provide two implementation schemes for a mid-drive motor using a resolver. In both schemes, the resolver is installed at the non-power output end of the shaft 2300A. Since the resolver stator wires need to be connected to the circuit board 7100 inside the mid-drive motor to send the induced signal to the circuit board 7100, and the circuit board 7100 is typically located in the transmission cavity 1003 within the main housing 1000, but the transmission cavity 1003 is not connected to or adjacent to the resolver mounting cavity 1002, it is necessary to connect the wires to the circuit board via a lead-in channel. Further optimization designs for the above two implementation schemes are described below:

[0256] In this embodiment, the stator mounting part 1010 and the partition plate 1020 can be integrally formed on the main housing 1000, or they can be connected to the main housing 1000 by means of a separate structure.

[0257] In this embodiment, a first fixing structure is provided on the transition housing 1200 outside the shaft hole 1210 to fix the resolver stator 3100. By fixing the resolver stator 3100 through the transition housing 1200, the resolver can be brought closer to the motor mounting cavity 1001, thereby reducing the length of the rotating shaft 2300A, making the overall structure more compact, and also making it easier to install and fix the resolver stator 3100.

[0258] In this embodiment, the first fixing structure includes an annular rib 1220 disposed on the transition housing 1200 and coaxially arranged with the shaft hole 1210. A fixing block 1230 is provided on the outer side of the annular rib 1220. The fixing block 1230 is connected to the transition housing 1200 and abuts against the outside of the resolver stator 3100. The annular rib 1220 provides a reference for fixing the resolver stator 3100. Since the transition housing 1200 and the main housing 1000 are directly connected, the coaxiality of the annular rib 1220 and the motor assembly 2000 is also better, allowing for better assembly of the resolver stator 3100 and the resolver rotor 3200 mounted on the rotating shaft 2300A. The annular rib 1220 can also further improve the structural strength of the transition housing 1200, thereby improving the resistance of the transition housing 1200 to deformation.

[0259] In this embodiment, the fixing block 1230 has an arc-shaped structure and the same curvature as the contact part of the resolver stator 3100. By using the arc-shaped fixing block 1230 to contact the resolver stator 3100, the assembly accuracy of the resolver stator 3100 can be better guaranteed.

[0260] In this embodiment, an annular groove 3120 is provided at the abutment portion of the resolver stator 3100, and the fixing block 1230 has an arc that matches the annular groove 3120. The fixing block 1230 can be engaged in the annular groove 3120 on the resolver stator 3100, so that after the fixing block 1230 is connected to the resolver stator 3100, it can fix and center the resolver stator 3100.

[0261] In this embodiment, a bearing mounting chamber 1240 is provided on the transition housing 1200 inside the shaft hole 1210. A bearing is installed in the bearing mounting chamber 1240 and is sleeved on the rotating shaft 2300A. The bearing mounting chamber 1240 also adopts a ring-shaped structure, similar to the structure of the annular rib 1220, which can further improve the structural strength of the transition housing 1200. At the same time, the bearing installed in the bearing mounting chamber 1240 can provide support for the rotating shaft 2300A, thereby making the structural layout more reasonable.

[0262] In this embodiment, alternatively, a second fixing structure can be provided on the inner side of the motor cover 1100 to fix the resolver stator. The second fixing structure has the same function as the first fixing structure, both fixing the resolver stator 3100. The difference is that the second fixing structure is located on the inner side of the motor cover 1100, while the first fixing structure is located on the transition housing 1200. The specific design of the second fixing structure can refer to the first fixing structure.

[0263] In this embodiment, the transition housing 1200 is made of magnetic shielding material; thereby, the motor assembly 2000 and the rotary transformer 3000 can be better isolated, reducing or eliminating electromagnetic interference between them.

[0264] In this embodiment, a gear is machined at the power output end 2350; the specific details can be found in the structural design of the shaft 2300 in the above embodiments, and will not be repeated here. When a gear is directly machined at the power output end 2350, the transmission effect of the mid-drive motor can be improved, the structure can be made more compact, and the cost can be reduced while improving the transmission efficiency.

[0265] In this embodiment, the end face of the resolver mounting end 2360 is connected to the third fixing structure 2361 to fix the resolver rotor 3200. The third fixing structure 2361 is a nut, and the size of the nut is larger than the diameter of the end face of the resolver mounting end 2360.

[0266] In this embodiment, two or three annular grooves 1011 are provided circumferentially on the inner wall of the stator mounting portion 1010. Adhesive is filled into the annular grooves 1011, so that the adhesive connects to the stator core after it is installed in the mounting cavity. Connecting the stator core to the stator mounting portion 1010 of the main housing 1000 by injecting adhesive into the annular grooves 1011 provides better fixation of the stator core, ensuring that the stator core remains stationary during operation of the motor assembly 2000. In this embodiment, multi-segment arc-shaped grooves can also be used instead of the annular grooves 1011, or a combination of arc-shaped grooves and annular grooves 1011 can be used to fix the stator core. Those skilled in the art will understand that the multi-segment arc-shaped groove method can better overcome the circumferential movement of the stator core.

[0267] In this embodiment, the connection between the annular groove 1011, the side of the arc groove away from the opening and the inner wall of the stator mounting part 1010 is set as a chamfer, rounded corner or bevel; thereby making it easier for the stator core to be assembled into the stator mounting part 1010.

[0268] In this embodiment, the surfaces of the annular groove 1011 and the arc-shaped groove are designed as friction surfaces, so that after the adhesive is injected, the contact area between the adhesive and the groove is larger and the fixing effect is better.

[0269] In this embodiment, the exterior of the main housing 1000 is also provided with heat dissipation fins 1030. The heat dissipation fins 1030 are arranged perpendicular to the axial direction of the rotating shaft 2300A and correspond to the position of the stator. Since the stator is directly connected to the inner wall of the main housing 1000, the heat of the stator can be conducted away in a timely manner. In the implementation process, heat dissipation fins can also be provided at other positions of heat-generating structures in the main housing 1000, and their effect is basically the same as that of the heat dissipation fins 1030 in this embodiment.

[0270] In this embodiment, the top edge of the heat dissipation fin 1030 is aligned with the outer surface of the main unit housing 1000 without the heat dissipation fin 1030; thus, the heat dissipation fin 1030 and the outer surface of the main unit housing 1000 have the same external dimensions, and the heat dissipation fin 1030 is prevented from being damaged when it protrudes from the surface of the main unit housing 1000 and encounters external impact.

[0271] In this embodiment, the arrangement direction of the heat dissipation fins 1030 is the same as the direction in which the mid-drive motor moves forward with the bicycle, so that airflow can pass between the heat dissipation fins while the bicycle is moving forward, thereby improving the heat dissipation effect.

[0272] The mid-mounted motor with a rotary transformer installed at the non-power output end of the shaft provided in this embodiment can further utilize a stator core, shaft, first-stage transmission gear, first-stage transmission gear shaft, mid-mounted motor transmission mechanism, etc. For details, please refer to the relevant descriptions in the above embodiments, which will not be repeated here.

[0273] like Figure 33-36 As shown, this embodiment also provides a mid-drive motor using a rotary transformer. In this embodiment, the rotary transformer is located at the power output end of the motor assembly 2000. The mid-drive motor provided in this embodiment includes a motor assembly 2000, a main housing 1000, and a rotary transformer 3000, wherein:

[0274] The motor assembly 2000 includes a stator 2100, a rotor, and a shaft 2300B. The shaft 2300B includes a rotor connection end 2370, a power output part 2380, and a resolver mounting end 2360. The power output part 2380 is located between the resolver mounting end 2360 and the rotor connection end 2370, and the rotor is mounted on the rotor connection end 2370.

[0275] The main housing 1000 is divided into a motor mounting cavity 1001 and a transmission cavity 1003 by a partition. The rotating shaft 2300B passes through the through hole in the partition. The stator 2100, the rotor and the rotor connection end 2370 of the rotating shaft 2300B are located in the motor mounting cavity 1001. The power output part 2380 and the resolver mounting end 2360 of the rotating shaft 2300B are located in the transmission cavity 1003.

[0276] The rotary transformer 3000 is located in the transmission cavity 1003 and includes a rotary stator 3100 and a rotary rotor 3200. The rotary rotor 3200 is installed on the rotary mounting end 2360 of the rotating shaft 2300B, and the rotary stator 3100 is fixedly connected to the main housing 1000 through a first fixing structure.

[0277] The mid-mounted motor provided in this embodiment has a resolver mounting end 2360 on the outside of the power output section 2380 of the rotating shaft 2300B for mounting the resolver rotor 3200 of the resolver 3000, thereby avoiding the prior art of mounting the induction magnet on the power output end of the rotating shaft 2300 (e.g., ...). Figure 29 As shown, the problem of tooth surface deformation caused by pressing the rotor core 2200 into the shaft 2300 is addressed by directly connecting the shaft 2300B to the rotary transformer 3000, which allows it to rotate synchronously with the shaft 2300B and is more accurate than the sensing signal detected by the induction magnet.

[0278] The mid-drive motor provided in this embodiment has the rotary transformer 3000 set in the transmission cavity 1003 of the main housing 1000, and the circuit board 7100 is usually also set in the transmission cavity 1003. Therefore, the rotary transformer 3000 can be directly connected to the circuit board 7100, without the need to connect the rotary transformer to the non-power output end of the rotating shaft as in the above embodiment, which requires a complex structural design for the wiring channel of the rotary transformer stator conductor.

[0279] The mid-drive motor provided in this embodiment also includes a circuit board 7100, which is disposed in the transmission cavity 1003, and the resolver stator 3100 is connected to the circuit board 7100 via wires.

[0280] The mid-mounted motor provided in this embodiment also includes a motor cover 1100, which is connected to the motor mounting cavity 1001 of the main housing 1000;

[0281] The motor cover 1100 contains a first bearing mounting chamber 1110, and the rotating shaft 2300B is connected to the first bearing mounting chamber 1110 via a first ball bearing 1111. A second bearing mounting chamber 1022 is provided on the partition 1020 surrounding the inner side of the through hole, and the rotating shaft 2300B is connected to the second bearing mounting chamber 1022 via a second ball bearing 1023. The two bearing chambers and the bearings inside provide support for the rotating shaft 2300B.

[0282] The mid-mounted motor provided in this embodiment also includes a main unit cover 1300, which is connected to the transmission cavity of the main unit housing 1000;

[0283] The main unit cover 1300 has a first fixing structure on the inner side corresponding to the position of the resolver mounting end 2360 to fix the resolver stator 3100.

[0284] In this embodiment, the first fixing structure includes an annular rib 1220 disposed inside the main cover 1300 and coaxially arranged with the shaft hole 1210. A fixing block 1230 is provided on the outer side of the annular rib 1220. The fixing block 1230 is connected to the inner side of the main cover 1300 and abuts against the outer side of the resolver stator 3100. The annular rib 1220 provides a reference for fixing the resolver stator 3100. Since the main cover 1300 and the main housing 1000 are directly connected, the coaxiality of the annular rib 1220 and the motor assembly 2000 is also better, allowing for better assembly of the resolver stator 3100 and the resolver rotor 3200 mounted on the rotating shaft 2300B. The annular rib 1220 can also further improve the structural strength of the main cover 1300, thereby improving the main cover 1300's resistance to deformation.

[0285] In this embodiment, the fixing block 1230 has an arc-shaped structure and the same curvature as the contact part of the resolver stator 3100. By using the arc-shaped fixing block 1230 to contact the resolver stator 3100, the assembly accuracy of the resolver stator 3100 can be better guaranteed.

[0286] In this embodiment, an annular groove 3120 is provided at the abutment portion of the resolver stator 3100, and the fixing block 1230 has an arc that matches the annular groove 3120. The fixing block 1230 can be engaged in the annular groove 3120 on the resolver stator 3100, so that after the fixing block 1230 is connected to the resolver stator 3100, it can fix and center the resolver stator 3100.

[0287] In this embodiment, the end face of the resolver mounting end 2360 is connected to the third fixing structure 2361 to fix the resolver rotor 3200. The third fixing structure 2361 is a nut, and the size of the nut is larger than the diameter of the end face of the resolver mounting end 2360.

[0288] In this embodiment, the exterior of the main housing 1000 is also provided with heat dissipation fins 1030. The heat dissipation fins 1030 are arranged perpendicular to the axial direction of the rotating shaft 2300A and correspond to the position of the stator. Since the stator is directly connected to the inner wall of the main housing 1000, the heat of the stator can be conducted away in a timely manner. In the implementation process, heat dissipation fins can also be provided at other positions of heat-generating structures in the main housing 1000, and their effect is basically the same as that of the heat dissipation fins 1030 in this embodiment.

[0289] In this embodiment, the top edge of the heat dissipation fin 1030 is aligned with the outer surface of the main unit housing 1000 without the heat dissipation fin 1030; thus, the heat dissipation fin 1030 and the outer surface of the main unit housing 1000 have the same external dimensions, and the heat dissipation fin 1030 is prevented from being damaged when it protrudes from the surface of the main unit housing 1000 and encounters external impact.

[0290] In this embodiment, the arrangement direction of the heat dissipation fins 1030 is the same as the direction in which the mid-drive motor moves forward with the bicycle, so that airflow can pass between the heat dissipation fins while the bicycle is moving forward, thereby improving the heat dissipation effect.

[0291] The mid-mounted motor with a rotary transformer installed at the power output end of the shaft provided in this embodiment can further utilize a stator core, shaft, first-stage transmission gear, first-stage transmission gear shaft, mid-mounted motor transmission mechanism, etc. For details, please refer to the relevant descriptions in the above embodiments, which will not be repeated here.

[0292] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0293] The above embodiments merely illustrate several implementation methods of the present invention, and their descriptions are relatively specific and detailed, but they should not be construed as limiting the scope of the invention patent. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these all fall within the protection scope of the present invention. Therefore, the protection scope of this invention patent should be determined by the appended claims.

Claims

1. A mid-drive motor drive system, comprising: Motor assembly (2000), including shaft (2300); The primary transmission gear set (4000) includes a primary transmission gear (4100) and a primary transmission gear shaft (4200). The primary transmission gear (4100) meshes with the rotating shaft (2300), and the primary transmission gear shaft (4200) is coaxially connected with the primary transmission gear (4100). The secondary transmission gear set (5000) meshes with the primary transmission gear shaft (4200) for transmission; The first-stage transmission gear shaft (4200) is characterized in that it includes an input end (4210), an output tooth (4220), and a support shaft (4230), wherein the input end (4210) is connected to the first-stage transmission gear (4100), the output tooth (4220) is located between the input end (4210) and the support shaft (4230), the diameter of the support shaft (4230) is smaller than the diameter of the output tooth (4220) and the input end (4210), and the support shaft (4230) is connected to a first needle roller bearing (4240). The outer diameter of the first needle roller bearing (4240) is smaller than the tip circle diameter of the output tooth (4220); The secondary transmission gear set (5000) includes a secondary transmission large gear (5100) and a secondary transmission small gear (5200) coaxially connected. The secondary transmission large gear (5100) meshes with the primary transmission gear shaft (4200), and the secondary transmission small gear (5200) drives the central shaft transmission mechanism (6000). The secondary transmission small gear (5200) is located on the side away from the primary transmission gear shaft (4200), so that the secondary transmission small gear (5200) corresponds to the position of the first needle roller bearing (4240) in the radial direction.

2. The transmission system according to claim 1, characterized in that, The primary transmission gear shaft (4200) passes through the bearing bracket (7200), and the support shaft (4230) is mounted in the first bearing mounting hole (1310) on the inner wall of the main cover (1300) via the first needle roller bearing (4240).

3. The transmission system of claim 2, wherein, The bearing bracket (7200) is connected between the main housing (1000) and the main cover (1300) to form a deceleration chamber, which houses the first-stage transmission wheel set (4000) and the second-stage transmission wheel set (5000).

4. The transmission system of claim 2, wherein, The inner wall of the main cover (1300) is also provided with a second bearing mounting hole (1320), and the shaft of the secondary transmission pinion (5200) is installed in the second bearing mounting hole (1320) through a fourth ball bearing (5210).

5. The transmission system according to claim 4, characterized in that, The first bearing mounting hole (1310) is tangent to the second bearing mounting hole (1320) or connected to the side wall.

6. The transmission system according to claim 1, characterized in that, The rotation axis distance Z between the secondary transmission wheel set (5000) and the primary transmission wheel set (4000) is 10-20mm.

7. The transmission system according to claim 6, characterized in that, The rotation axis distance Z between the secondary transmission wheel set (5000) and the primary transmission wheel set (4000) is 15.3 mm.

8. The transmission system according to claim 1, characterized in that, The diameter of the first needle roller bearing (4240) is 5.5-10.5 mm.

9. The transmission system according to claim 8, characterized in that, The diameter of the first needle roller bearing (4240) is 8 mm.

10. The transmission system according to claim 1, characterized in that, It also includes a central shaft drive mechanism (6000), which comprises: Central axis (6100); Torque sensor (6300) is fixedly mounted on the central shaft; The toothed plate positioning sleeve (6200) is connected to the torque sensor at one end via a first one-way valve (6500), and is fixedly connected to the toothed plate at the other end; The central shaft gear (6400) is connected to the toothed locating sleeve via a second one-way device (6600); and the central shaft gear (6400) meshes with the secondary transmission pinion (5200).

11. The transmission system according to claim 10, characterized in that, The central shaft gear includes: Gear section (6410); The support part (6420) is located on the inner side of the gear part (6410) in the radial direction and is used to connect with the toothed disc positioning sleeve (6200) via the third ball bearing (6003); The transmission part (6430) is located on one side of the support part (6420) in the axial direction and is used to connect with the toothed disc positioning sleeve (6200) via the second one-way device (6600).

12. The transmission system according to claim 11, characterized in that, The gear part (6410), the support part (6420), and the transmission part (6430) form an L-shaped layout, and in the axial direction, the transmission part (6430) is located outside the support part (6420).

13. The transmission system according to claim 12, characterized in that, The toothed disc positioning sleeve (6200) is provided with an annular step structure (6210), wherein the first one-way valve (6500) is disposed in the annular step structure (6210), the second one-way valve (6600) is close to the annular step structure (6210), and the outer diameter of the transmission part (6430) does not exceed the outer diameter of the annular step structure (6210).

14. The transmission system according to claim 12, characterized in that, The toothed disc positioning sleeve (6200) is connected to the central shaft through two needle roller bearings, and the two needle roller bearings are located on both sides of the support.

15. The transmission system according to claim 14, characterized in that, The two needle roller bearings are a second needle roller bearing (6001) and a third needle roller bearing (6002), wherein the second needle roller bearing (6001) is located outside the third needle roller bearing (6002), and the third needle roller bearing (6002) is connected to the torque sensor (6300).

16. The transmission system according to claim 15, characterized in that, The inner diameter of the third needle roller bearing (6002) is larger than the inner diameter of the second needle roller bearing (6001).

17. The transmission system according to claim 10, characterized in that, The torque sensor (6300) is fixedly connected to the central shaft (6100) via a spline; the central shaft (6100) is a hollow tube shaft, and both ends of the central shaft (6100) are respectively connected to a crank.

18. The transmission system according to claim 1, characterized in that, The primary transmission gear includes a central insert (4120) and an outer ring tooth (4110). The central insert (4120) has a central shaft hole. The outer ring tooth (4110) is connected to the outer circumference of the central insert (4120) and is arranged coaxially. The axial width of the outer ring tooth (4110) is greater than the axial width of the central insert (4120), and both ends of the outer ring tooth (4110) extend beyond the central insert (4120) in the axial direction. The central insert (4120) is made of metal, and the outer ring tooth (4110) is made of non-metallic material.

19. The transmission system according to claim 18, characterized in that, The outer circumferential surface of the central insert (4120) is provided with a reinforcing structure; the reinforcing structure protrudes or is recessed on the outer circumferential surface.

20. The transmission system according to claim 19, characterized in that, The reinforcing structure consists of reinforcing teeth (4121), knurling, or splines evenly distributed around the outer circumference of the central insert (4120).

21. The transmission system according to claim 20, characterized in that, The reinforcing tooth (4121) is divided into at least three segments in the axial direction.

22. The transmission system according to claim 20, characterized in that, The tooth tip of the reinforcing tooth (4121) is an arc surface or a surface with an obtuse angle, and the width of the tooth tip is not less than 0.2 mm.

23. The transmission system according to claim 20, characterized in that, The number of splines is not less than 4, and the spline modulus is not less than 0.

25.

24. The transmission system according to claim 18, characterized in that, The outer ring teeth (4110) are injection molded on the outer circumference of the central insert (4120).

25. The transmission system according to claim 1, characterized in that, The rotating shaft (2300) includes a shaft-shaped portion (2310) and a toothed portion (2320). The surface of the toothed portion (2320) is machined to extend to the end of the toothed portion. The toothed portion (2320) includes an engagement area (2321) and a non-engaging area (2322). The engagement area (2321) is connected to the shaft-shaped portion (2310). The non-engaging area (2322) is located at the free end of the rotating shaft (2300). The toothed surface of the non-engaging area (2322) is provided with an annularly cut partition groove (2323), or the toothed surface at the junction of the engagement area (2321) and the non-engaging area (2322) is provided with an annularly cut partition groove (2323).

26. The transmission system according to claim 25, characterized in that, The depth of the partition groove (2323) does not exceed the height of the tooth surface; and or, the length between the partition groove (2323) and the end of the tooth (2320) does not exceed one-third of the length of the tooth surface.

27. The transmission system according to claim 25, characterized in that, A groove (2324) is provided on the end face of the rotating shaft (2300) at one end of the shaft-shaped part (2310), and an induction magnet (2345) is installed in the groove (2324).

28. The transmission system according to claim 27, characterized in that, The groove (2324) is circular, and an inner conical surface is provided at the center of the groove (2324).

29. The transmission system according to claim 27, characterized in that, The diameter of the groove (2324) is smaller than the diameter of the tooth root circle.

30. The transmission system according to claim 27, characterized in that, The induction magnet is also circular, and the diameter of the induction magnet (2345) is slightly larger than the diameter of the groove (2324), so that the induction magnet (2345) is installed in the groove (2324) by interference fit; Alternatively, the inductive magnet (2345) is connected in the groove (2324) by a colloid.

31. The transmission system according to claim 25, characterized in that, The tooth surface is either helical or straight.

32. A mid-drive motor, characterized in that, Includes the transmission system as described in any one of claims 1-31.

33. The mid-drive motor according to claim 32, characterized in that, Also includes The motor assembly (2000) includes a stator (2100), a rotor, and a shaft (2300A). The shaft (2300A) includes a rotor connection portion (2340), a power output end (2350), and a resolver mounting end (2360). The rotor connection portion (2340) is located between the power output end (2350) and the resolver mounting end (2360). The rotor core (2200) of the rotor is connected to the rotor connection portion (2340). The main housing (1000) has a stator mounting part (1010) inside which the stator (2100) is provided. The stator mounting part (1010) is separated from the interior of the main housing (1000) by a partition (1020). The opening of the stator mounting part (1010) faces outward. The resolver mounting end (2360) of the rotating shaft (2300A) extends outward from the opening of the stator mounting part (1010). The power output end (2350) of the rotating shaft (2300A) extends inward through the partition (1020) and is located inside the main housing (1000). The transition housing (1200) is connected to the opening of the stator mounting portion (1010) of the main housing (1000) to form a motor mounting cavity (1001). The transition housing (1200) is provided with a shaft hole (1210) that allows the rotating shaft to pass through, and the resolver mounting end (2360) is located outside the shaft hole (1210). The motor cover (1100) is connected to the transition housing (1200) outside the shaft hole (1210) to form a resolver mounting cavity (1002) outside the shaft hole (1210) and to house the resolver mounting end (2360) therein; A resolver (3000), located in the resolver mounting cavity, includes a resolver stator (3100) and a resolver rotor (3200), wherein the resolver rotor (3200) is mounted on the resolver mounting end (2360).

34. The mid-drive motor according to claim 32, characterized in that, Also includes The motor assembly (2000) includes a stator (2100), a rotor, and a shaft (2300A). The shaft (2300A) includes a rotor connection portion (2340), a power output end (2350), and a resolver mounting end (2360). The rotor connection portion (2340) is located between the power output end (2350) and the resolver mounting end (2360). The rotor core (2200) of the rotor is connected to the rotor connection portion (2340). The main housing (1000) has a stator mounting part (1010) inside which the stator (2100) is provided. The stator mounting part (1010) is separated from the interior of the main housing (1000) by a partition (1020). The opening of the stator mounting part (1010) faces outward. The resolver mounting end (2360) of the rotating shaft (2300A) extends outward from the opening of the stator mounting part (1010). The power output end (2350) of the rotating shaft (2300A) extends inward through the partition (1020) and is located inside the main housing (1000). A transition housing (1200) is connected to the stator mounting portion (1010) of the main housing (1000) to form a motor mounting cavity (1001). The transition housing (1200) is provided with a shaft hole (1210) that allows the rotating shaft to pass through, and the resolver mounting end (2360) is located outside the shaft hole (1210). The motor cover (1100) is aligned with the opening of the stator mounting portion (1010) of the main housing (1000) to form a resolver mounting cavity (1002) on the outside of the shaft hole (1210) and to house the resolver mounting end (2360) therein; A resolver (3000), located in the resolver mounting cavity, includes a resolver stator (3100) and a resolver rotor (3200), wherein the resolver rotor (3200) is mounted on the resolver mounting end (2360).

35. The mid-drive motor according to claim 32, characterized in that, Also includes: The motor assembly (2000) includes a stator (2100), a rotor, and a shaft (2300B). The shaft (2300B) includes a rotor connection end (2370), a power output section (2380), and a resolver mounting end (2360). The power output section (2380) is located between the resolver mounting end (2360) and the rotor connection end (2370). The rotor is mounted on the rotor connection end (2370). The main housing (1000) is divided into a motor mounting cavity (1001) and a transmission cavity (1003) by a partition. The rotating shaft (2300B) passes through a through hole in the partition. The stator (2100), the rotor, and the rotor connection end (2370) of the rotating shaft (2300B) are located in the motor mounting cavity (1001). The power output part (2380) and the resolver mounting end (2360) of the rotating shaft (2300B) are located in the transmission cavity (1003). A rotary transformer (3000) is located in the transmission cavity (1003) and includes a rotary stator (3100) and a rotary rotor (3200), wherein the rotary rotor (3200) is mounted on the rotary mounting end (2360) of the rotating shaft (2300B), and the rotary stator (3100) is fixedly connected to the main housing (1000) by a first fixing structure.

36. An electric bicycle, characterized in that, Includes the transmission system as described in any one of claims 1-31.

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