A mid-mounted variable speed motor

Abstract

The present application relates to a mid-mounted variable speed motor, which includes a motor body, a housing mechanism, a central shaft mechanism, a power transmission mechanism and a speed change mechanism; the speed change mechanism includes a speed change input assembly, a speed change selection assembly and a speed change output assembly; the speed change input assembly includes a plurality of intermediate gears of different diameters, the plurality of intermediate gears are coaxially arranged, and the speed change output assembly is connected to the power transmission mechanism; the speed change output assembly is connected to the central shaft mechanism in a transmission manner, the speed change output assembly includes a speed change gear having the same number as the intermediate gears, the speed change gears are coaxially arranged, and are used for meshing and transmission connection with the corresponding intermediate gears; the speed change selection assembly includes a shift coupling member, the shift coupling member reciprocates in the direction of the speed change gear axis to switch the transmission relationship between the speed change gear and the intermediate gear. The present application integrates the speed change structure inside the motor.

Description

Technical Field

[0001] The present application relates to the field of power-assisted bicycles, and in particular to a mid-mounted variable-speed motor. Background Art

[0002] Power-assisted bicycles (also known as E-Bikes) are a new type of transportation that adds batteries and motors to traditional bicycles. It combines human riding with electric power assistance through a power-assisted system. In power-assisted bicycle technology, there are two main types of motor installation positions: one is a mid-mounted motor installed in the middle of the frame, and the other is a hub motor installed in the wheel hub. The mid-mounted motor is conducive to the uniform layout of the vehicle mass and improves the stability of the vehicle, so it performs better in terms of riding experience.

[0003] The mid-mounted motors currently on the market are conventional reduction mid-mounted motors; for example, the structure disclosed in the Chinese patent with the authorization announcement number CN103661762B, the mid-mounted motor includes a planetary reduction mechanism for reducing the motor output. However, since power-assisted bicycles need to adapt to different road conditions, they usually have a speed shifting device, and the shifting structure usually consists of sprockets of different diameters. The power-assisted bicycle transmission chain is controlled to engage with different sprockets to achieve gear shifting. When using a conventional reduction mid-mounted motor, it is still necessary to rely on the speed shifting device of the vehicle body to achieve speed change. Summary of the invention

[0004] In view of the defects in the prior art, the present application provides a mid-mounted variable speed motor.

[0005] The present application provides a mid-mounted variable speed motor, which adopts the following technical solution:

[0006] A mid-mounted variable-speed motor comprises a motor body, a housing mechanism, a central axis mechanism, a power-assisted transmission mechanism and a speed-changing mechanism, wherein the central axis mechanism, the power-assisted transmission mechanism and the speed-changing mechanism form a multi-parallel axis structure; wherein the central axis mechanism is used to input pedal power and output motor power; the power-assisted transmission mechanism is connected between the motor body and the speed-changing mechanism; the speed-changing mechanism comprises a speed-changing input assembly, a speed-changing selection assembly and a speed-changing output assembly; wherein the speed-changing input assembly comprises a plurality of intermediate gears of different diameters, the plurality of intermediate gears being coaxially arranged to connect the speed-changing output assembly and the power-assisted transmission mechanism; the speed-changing output assembly is transmission-connected with the central axis mechanism, the speed-changing output assembly comprises speed-changing gears having the same number as the intermediate gears, the speed-changing gears being coaxially arranged and used to mesh with the corresponding intermediate gears for transmission connection; the speed-changing selection assembly comprises a shift coupling member, the shift coupling member reciprocates in the direction of the speed-changing gear axis to switch the transmission relationship between the speed-changing gear and the intermediate gear.

[0007] Optionally, the speed change output assembly further includes an output intermediate shaft, the speed change gear is loosely sleeved on the output intermediate shaft, the shift coupling component includes a coupling sprocket, and the speed change gear is provided with a connecting sprocket for meshing and connecting with the coupling sprocket in the axial direction of the speed change gear.

[0008] The central axis mechanism, the power transmission mechanism and the speed change mechanism form a multi-parallel axis structure. The shift coupling member realizes engagement and separation with the speed change gear in the axial direction of the speed change gear. The overall structure is compact, which is conducive to integrating the speed change structure inside the central motor housing mechanism.

[0009] Optionally, the tooth shape of the combining sprocket is triangular, and the angle between one tooth surface and the center axis of the combining sprocket is 3-5 degrees; the tooth shape of the connecting sprocket is triangular, and the angle between one tooth surface and the center axis of the connecting sprocket is 3-5 degrees.

[0010] The tooth shape used for clutch is designed to be approximately a right triangle, with one side making an angle of 3-5 degrees with the central axis, so that gear shifting can be performed without stopping the motor.

[0011] Optionally, the speed selection assembly also includes a shift hub, a shift fork and a shift pin; wherein, a curved groove is provided on the surface of the shift hub; the shift fork includes a cam sleeve and a coupling sleeve with parallel axes, the cam sleeve is sleeved on the shift hub, the cam sleeve and the shift hub are connected via a shift pin, so that the rotation of the shift hub is converted into linear movement of the cam sleeve, and the shift coupling member is rotatably sleeved in the coupling sleeve.

[0012] Optionally, a plurality of the shift forks are provided, the shift coupling members are the same in number as the shift forks and are provided in one-to-one correspondence, and the number of the curved grooves provided on the shift hub is consistent with the number of the shift forks.

[0013] When the speed change mechanism is working, the shift hub is driven to rotate, driving the shift fork to move along the axial direction of the shift hub, so that the shift fork is combined with different speed gears through the shift coupling member to complete the shifting and speed changing action between different transmission gear sets. Since the axis of the coupling sleeve is parallel to the axis of the cam sleeve, the shift selection assembly and the shift output assembly are arranged in a double axis as a whole, and the structure is more compact.

[0014] Optionally, the shift hub is coaxially fixedly connected with a fixing boss, and the fixing boss is circumferentially provided with a fixing recess, and the speed selection assembly also includes a fixing pin, one end of which is connected to a fixing member that can be elastically extended, and the fixing member is circumferentially abutted against the fixing boss, and the position of the fixing recess corresponds to the position where the direction of the curved groove changes.

[0015] The fixing member is in circumferential contact with the fixing boss. When the fixing boss rotates to a certain position with the shift hub, the fixing member pops out and snaps into the corresponding fixing recess, thereby playing a role of locking the gear and preventing the gear from falling out due to external force rotating the shift hub during operation.

[0016] Optionally, the shell mechanism includes a first outer shell, a second outer shell and an inner shell; the first outer shell and the second outer shell cooperate to form an internal space, the internal space depth of the first outer shell is less than the internal space depth of the second outer shell, and the inner shell cooperates with the second outer shell to form a closed space for accommodating a power transmission mechanism.

[0017] The first outer shell and the second outer shell adopt an asymmetric design, so that the second outer shell with a deeper internal depth reserves a closed space, and the internal space can be divided and sealed by using the internal single shell and the original external shell. The power transmission mechanism is independently divided in its own space, reducing the external environmental factors on the torque sensor, improving the detection accuracy of the torque sensor, accurately reading the power input by the rider, providing the rider with a more suitable auxiliary power, and thus improving the rider's riding experience.

[0018] The power transmission mechanism is located in a confined space, and liquid lubricant can be added in the confined space. As the gear mechanism operates, the liquid lubricant flows to lubricate the meshing gear pair. Due to proper lubrication, this application can use steel gears to increase the service life of the power transmission mechanism, so that the mid-mounted motor can take into account the life of the transmission structure and the rider experience. At the same time, the steel gear transmission performs better under high power output.

[0019] Optionally, the second outer shell is provided with a plurality of inspection openings, the positions of the inspection openings correspond to the positions of the speed input assembly and the speed selection assembly, the second outer shell is also provided with a accommodating cavity for accommodating the motor body, and the shell structure also includes a cover plate for shielding the inspection openings and the accommodating cavity.

[0020] During the maintenance phase, the cover can be opened to quickly observe the status of the internal structure of the mid-mounted speed-changing motor, and the motor fault position can be quickly located without removing the mid-mounted speed-changing motor from the frame.

[0021] Optionally, the speed change output assembly is provided in a plurality of groups, and the number of the speed change selection assemblies is consistent with the number of the speed change output assemblies.

[0022] The structural design of the speed selection component and the speed output component of the present application facilitates the flexible design of multiple gears of the motor as a whole. When more motor gears are set, the overall internal structure remains compact.

[0023] Optionally, the speed change input assembly includes an input intermediate shaft, and the intermediate gear is connected to the input intermediate shaft through a plurality of step positioning members, and the plurality of step positioning members are arranged at intervals along the circumference of the input intermediate shaft, and the step positioning members are divided into a plurality of steps along the axial direction of the intermediate shaft, and different steps have different radial thicknesses, and the end face of the step stage is used to abut against the end face of the intermediate gear, and the outer circumferential surface of the step stage is used to abut against the inner ring of the intermediate gear, and key grooves are formed between the circumferentially adjacent step positioning members.

[0024] In summary, the present application includes at least one of the following beneficial technical effects:

[0025] The speed change structure is integrated into the middle motor, so the power-assisted bicycle does not need to be equipped with an additional speed change structure.

[0026] The central axis mechanism, power transmission mechanism and speed change mechanism form a multi-parallel axis structure with a compact overall structure. After the speed change structure is integrated into the central motor, the overall volume of the central speed change motor can be controlled.

[0027] The structural design of the speed selection component and the speed output component facilitates the flexible design of multiple gears of the motor as a whole. When more motor gears are set, the internal structure as a whole remains compact.

[0028] The clutch gear used for gear shifting is designed to be a right triangle structure, with one side of the gear shifting at an angle of 3-5 degrees to the central axis, which can ensure a good gear locking effect and enable gear shifting without stopping the motor.

[0029] The internal single shell is matched with the original external shell to complete the internal space division and sealing, and the power transmission mechanism is independently divided in its own space, which reduces the external environmental factors of the torque sensor, improves the detection accuracy of the torque sensor, and accurately reads the power input by the rider, providing the rider with more suitable auxiliary power, thereby improving the rider's riding experience;

[0030] The power transmission mechanism is located in a confined space, and liquid lubricant can be added in the confined space to lubricate the meshing gear pair. Steel gears can be used to increase the service life of the power transmission mechanism, so that the mid-mounted motor can take into account both the life of the transmission structure and the rider experience. At the same time, the steel gear transmission performs better under high power output;

[0031] During the maintenance phase, the cover can be opened to quickly observe the status of the internal structure of the mid-mounted speed-changing motor, and the motor fault position can be quickly located without removing the mid-mounted speed-changing motor from the frame. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1 It is a schematic diagram of the overall structure of a mid-mounted variable speed motor of the present application.

[0033] Figure 2 It is a partial exploded view of a mid-mounted variable speed motor of the present application.

[0034] Figure 3 This is a partial exploded view of a mid-mounted variable speed motor of the present application from another perspective.

[0035] Figure 4 This is an internal structure diagram of a mid-mounted variable speed motor of the present application.

[0036] Figure 5 It is a cross-sectional view of a central axis mechanism of a centrally mounted variable speed motor of the present application.

[0037] Figure 6 This is a structural schematic diagram of a mid-mounted variable speed motor of the present application with the housing mechanism hidden.

[0038] Figure 7 It is a schematic diagram of the connection structure between the central shaft mechanism and the speed change mechanism in a central speed change motor of the present application.

[0039] Figure 8 It is a structural schematic diagram of an input intermediate shaft in a mid-mounted variable speed motor of the present application.

[0040] Fig. 9 It is a schematic diagram of the overall structure of a speed selection component in a mid-mounted speed-changing motor of the present application.

[0041] Fig.10 It is a schematic structural diagram of a shift hub in a mid-mounted variable speed motor of the present application.

[0042] Fig.11 It is a structural schematic diagram of a shift fork in a mid-mounted speed-changing motor of the present application.

[0043] Fig.12 It is a structural schematic diagram of a shift coupling component in a mid-mounted variable speed motor of the present application.

[0044] Fig.13 It is a schematic diagram of the connection structure of a shift selection component and a shift output component in a mid-mounted variable speed motor of the present application.

[0045] Fig.14 It is a structural schematic diagram of an output intermediate shaft in a mid-mounted variable speed motor of the present application.

[0046] Fig.15 It is a schematic structural diagram of a speed-changing gear in a mid-mounted speed-changing motor of the present application.

[0047] Fig.16 It is a structural cross-sectional view of a speed change gear in a mid-mounted speed change motor of the present application.

[0048] Fig.17These are various tooth profile diagrams of clutch gears.

[0049] Fig.18 It is a schematic diagram of the operating status of one set of speed selection components in a mid-mounted speed-changing motor of the present application.

[0050] Fig.19 It is a schematic diagram of the connection structure of a speed-changing input component and a speed-changing output component in a mid-mounted speed-changing motor of the present application.

[0051] Explanation of reference numerals: 100, housing mechanism; 101, first accommodating chamber; 110, first outer housing; 111, inner housing; 120, second outer housing; 121, first cover plate; 131, second cover plate; 132, third cover plate; 200, middle shaft mechanism; 210, middle shaft; 220, middle shaft input gear; 230, middle shaft output gear; 240, middle shaft output sprocket; 251, torsion bar; 252, torque sensor; 300, power transmission mechanism ; 310, motor output shaft; 311, primary driving gear; 321, primary driven gear; 322, secondary driving gear; 331, secondary driven gear; 332, speed change input gear; 400, speed change mechanism; 410, speed change input assembly; 411, input intermediate shaft; 412, intermediate gear; 4121, first intermediate gear; 4122, second intermediate gear; 4123, third intermediate gear; 4124, fourth intermediate gear; 413, stage Step positioning member; 4131, first positioning portion; 4132, mounting portion; 4133, second positioning portion; 4134, fixing groove; 414, fixing ring; 420, speed selection assembly; 421, shift hub; 4211, first curved groove; 4212, second curved groove; 4213, fixed gear boss; 422, shift fork; 4221, cam sleeve; 4222, coupling sleeve; 4223, shift boss; 423, shift coupling member; 4231, Combining wheel; 4232, combining toothed disc; 4233, connecting key; 424, shift pin; 425, fixing pin; 430, speed change output assembly; 431, output intermediate shaft; 432, speed change gear; 4320, speed change output gear; 4321, first speed change gear; 4322, second speed change gear; 4323, third speed change gear; 4324, fourth speed change gear; 433, connecting toothed disc; 4331, first tooth surface; 4332, second tooth surface. DETAILED DESCRIPTION

[0052] The following is combined with Figure 1-19 , further details of this application are given.

[0053] The embodiment of the present application discloses a mid-mounted variable speed motor.

[0054] A mid-mounted variable speed motor is used to be installed on the frame of a power-assisted bicycle, and includes a housing mechanism 100, a middle axis mechanism 200, a motor body, a power-assisted transmission mechanism 300, and a speed-changing mechanism 400. The rider drives the power-assisted bicycle to start through the middle axis mechanism 200, and the mid-mounted variable speed motor detects the power input by the rider, determines the power output of the motor required according to the rider's input power, and controls the power-assisted transmission mechanism 300 to output auxiliary power. The auxiliary power output by the power-assisted transmission mechanism 300 reacts to the middle axis mechanism 200 through the speed-changing mechanism 400, so that the rider's manpower and the auxiliary power of the motor jointly drive the power-assisted bicycle forward. When the riding road conditions change, the rider can also adjust the gear position by controlling the speed-changing mechanism 400.

[0055] Reference Figure 1-Figure 4 The housing mechanism 100 includes a first housing 110 and a second housing 120, and the mid-speed motor is connected to the power-assisted bicycle frame through the first housing 110 and the second housing 120. The mid-speed motor is located in the inner space formed by the first housing 110 and the second housing 120.

[0056] The second outer shell 120 is internally provided with a first accommodating chamber 101 that is connected to the outside and is used to place the motor body, which includes a stator and a rotor, which will not be described in detail here. The housing mechanism 100 also includes a first cover plate 121, which is arranged at a position corresponding to the first accommodating chamber 101. The first cover plate 121 is connected to the second outer shell 120, and is used to protect and shield the motor body in the first accommodating chamber 101. By providing the first accommodating chamber 101 and the first cover plate 121, the placement position of the motor body in the central variable speed motor is relatively independent, which can reduce the mutual influence between the mechanisms, and by removing the first cover plate 121, the status of the motor body can be checked in time, and the motor body failure can be quickly eliminated during the maintenance stage, reducing the need for disassembly and assembly of the entire machine.

[0057] The first outer shell 110 and the second outer shell 120 are designed asymmetrically, that is, the spatial depth inside the first outer shell 110 is smaller than the spatial depth inside the second outer shell 120. The shell mechanism 100 also includes an inner shell 111. The inner shell 111 is located in the internal space formed by the first outer shell 110 and the second outer shell 120, and is sealed and connected to the inner surface of the second outer shell 120, thereby separating an independent closed space in the internal space formed by the first outer shell 110 and the second outer shell 120, and the power transmission mechanism 300 is located in the closed space. The internal depth of the second outer shell 120 is designed to be deeper, and the position of the closed space is reserved. The internal space can be divided and sealed by using an internal single shell in combination with the original external shell.

[0058] Reference Figure 5The middle shaft mechanism 200 includes a middle shaft 210, a middle shaft input gear 220, a middle shaft output gear 230, a middle shaft output sprocket 240, a torsion bar 251 and a torque sensor 252. The middle shaft input gear 220, the middle shaft output gear 230, the middle shaft output sprocket 240, the torsion bar 251 and the torque sensor 252 are all sleeved on the middle shaft 210. The middle shaft input gear 220 serves as the input end of the rider's pedaling power, and the middle shaft output gear 230 serves as the motor power output end of the mid-mounted variable speed motor. The two ends of the middle shaft 210 are respectively extended to the outside of the first outer shell 110 and the second outer shell 120, and are connected to the frame. The middle shaft output sprocket 240 is located outside the housing mechanism 100 and is connected to the power-assisted bicycle chain. The torque sensor 252 can be a stress strain torque sensor or a magnetoresistive torque sensor. The torque sensor 252 detects the power of the input torsion bar 251 and outputs appropriate power according to the power of the rider.

[0059] A control circuit board is also provided in the housing mechanism 100 , and the torque sensor 252 is electrically connected to the control circuit board. The control circuit board can analyze the data detected by the torque sensor 252 and control the output of the motor body.

[0060] The measurement data of the torque sensor 252 is easily affected by environmental factors such as temperature and vibration. Through the structure of the outer double shell and the inner single shell of the shell mechanism 100, the motor body and the power transmission mechanism 300 are independently divided in their own space, thereby reducing the external environmental factors to the torque sensor 252 and improving the detection accuracy of the torque sensor 252. Through the analysis of the control circuit board, the power input by the rider is accurately read, providing the rider with more suitable auxiliary power, thereby improving the rider's riding experience.

[0061] Reference Figure 6 The power transmission mechanism 300 includes a motor output shaft 310, a primary driving gear 311, a primary driven gear 321, a secondary driving gear 322, a secondary driven gear 331 and a speed change input gear 332. The motor output shaft 310 is connected to the rotor of the motor body, the primary driving gear 311 is coaxially fixedly connected to the motor output shaft 310, the primary driven gear 321 is coaxially fixedly connected to the secondary driving gear 322, and the secondary driven gear 331 is coaxially fixedly connected to the speed change input gear 332. The primary driving gear 311 is meshedly connected to the primary driven gear 321, and the secondary driving gear 322 is meshedly connected to the secondary driven gear 331. The speed change input gear 332 is connected to the speed change mechanism 400.

[0062] Transmission mid-mounted motors mostly use an open transmission structure. Since there are other parts inside the mid-mounted motor, grease is often used to lubricate the transmission structure. Power-assisted bicycles have high requirements for rider experience. In order to reduce the sense of frustration during riding, transmission gears use nylon teeth. The vibration generated during the operation of power-assisted bicycles has a great impact on the lubrication and life of nylon teeth.

[0063] In the present application, the power transmission mechanism 300 is located in the enclosed space formed by the inner housing 111 and the second outer housing 120. Liquid lubricant can be added in the enclosed space. As the gear mechanism operates, the liquid lubricant flows to lubricate the meshing gear pair. Due to proper lubrication, the present application can use steel gears to increase the service life of the power transmission mechanism 300, so that the mid-mounted motor can take into account both the life of the transmission structure and the rider experience. At the same time, the steel gear transmission performs better under high power output.

[0064] Reference Figure 6-Figure 8 The speed change mechanism 400 includes a speed change input assembly 410, a speed change selection assembly 420 and a speed change output assembly 430. The speed change input assembly 410 includes an input intermediate shaft 411 and a plurality of intermediate gears 412 of different diameters. The intermediate gears 412 are coaxially fixedly connected to the input intermediate shaft 411.

[0065] There are many ways to connect the intermediate gear 412 to the input intermediate shaft 411; for example, the intermediate gear 412 can be integrally formed with the input intermediate shaft 411; or the intermediate gear 412 and the input intermediate shaft 411 can be fixedly connected by providing a step positioning member 413 and a fixing ring 414 on the input intermediate shaft 411.

[0066] A plurality of step positioning members 413 are arranged at intervals around the axis of the input intermediate shaft 411, and the step positioning members 413 are fixedly connected to the input intermediate shaft 411. The step positioning member 413 is divided into a plurality of steps along the axial direction of the input intermediate shaft 411, and different steps have different radial thicknesses. Figure 8Take a step positioning member 413 in the middle upper part as an example, it has four steps, namely, a first positioning portion 4131, a mounting portion 4132, a second positioning portion 4133 and a fixing groove 4134. The inner ring of the intermediate gear 412 is provided with a spline, and the intermediate gear 412 is sleeved on the input intermediate shaft 411, and its lower end face is abutted and positioned with the upper end face of the first positioning portion 4131, and a keyway is formed between the circumferentially adjacent step positioning members 413, and the spline provided on the inner ring of the intermediate gear 412 is inserted into the keyway formed between the step positioning members 413. The second positioning portion 4133 is spaced apart from the mounting portion 4132, and a fixing groove 4134 is formed for installing the fixing ring 414. After the fixing ring 414 is inserted into the fixing groove 4134, the intermediate gear 412 is clamped and installed at the position of the mounting portion 4132. A plurality of intermediate gears 412 may also be mounted on the step positioning member 413 , and a plurality of mounting portions 4132 are provided correspondingly, and the radial thickness of the plurality of mounting portions 4132 decreases along the direction from the first positioning portion 4131 to the second positioning portion 4133 .

[0067] Reference Fig. 9 The gear selection assembly 420 includes a shift hub 421, a shift fork 422 and a shift coupling member 423. When the shift mechanism is working, the shift hub 421 is driven to rotate, driving the shift fork 422 to move axially along the shift hub 421, so that the shift fork 422 is coupled with different speed gears 432 through the shift coupling member 423 to complete the shifting action between different transmission gear sets.

[0068] Reference Fig.10 The shift hub 421 is a hollow cylindrical structure as a whole, and is integrally formed with the fixed gear boss 4213. The shift hub 421 and the fixed gear boss 4213 are coaxially arranged, and the outer diameter of the fixed gear boss 4213 is larger than the outer diameter of the shift hub 421. The shift hub 421 can rotate around its own axis. The outer surface of the shift hub 421 is correspondingly provided with a curved groove, so that the shift hub 421 acts as a cylindrical cam.

[0069] Figure 9-10 The speed selection assembly 420 shown in the figure has a four-speed shifting function, so the shift hub 421 is provided with two curved grooves, namely a first curved groove 4211 and a second curved groove 4212; the shift fork 422 is provided with two upper and lower groups.

[0070] Reference Fig.11 and Fig.12The shift fork 422 includes a cam sleeve 4221, a coupling sleeve 4222 and a shift boss 4223, and the three are integrally formed. The axis of the cam sleeve 4221 is parallel to the axis of the coupling sleeve 4222. The cam sleeve 4221 is movably sleeved on the shift hub 421, and the coupling sleeve 4222 is connected to the shift coupling member 423. The shift boss 4223 is arranged on the outer surface of the cam sleeve 4221 and is a hollow cylindrical structure. The axis of the shift boss 4223 is perpendicular to the axis of the cam sleeve 4221. The shift fork 422 is connected to the shift hub 421 through the shift pin 424. The shift pin 424 is movably embedded in the shift boss 4223 and moves in the first curved groove 4211 or the second curved groove 4212.

[0071] The shift coupling member 423 includes a coupling wheel 4231, a coupling toothed disc 4232 and a connecting key 4233. The coupling sleeve 4222 is coaxially sleeved on the coupling wheel 4231, and the coupling wheel 4231 can rotate around its own axis. The coupling toothed disc 4232 faces the upper and lower end surfaces of the coupling wheel 4231 so that the shift coupling member 423 can mesh with the speed gear 432 along its own axis. In this embodiment, the tooth shape of the coupling toothed disc 4232 is approximately a right triangle.

[0072] Reference Fig.13 The speed change output assembly 430 includes an output intermediate shaft 431 and a plurality of speed change gears 432. The number of the speed change gears 432 is designed according to the number of gears. Fig.14 The output intermediate shaft 431 is a shaft with splines arranged in the circumferential direction. The speed change gears 432 have different diameters and are coaxially sleeved on the output intermediate shaft 431. The shift coupling member 423 is connected to the output intermediate shaft 431 through a connecting key 4233. The speed change gears 432 and the output intermediate shaft 431 are clearance-matched. Fig.15 The end surface of the speed change gear 432 is provided with a connecting toothed disc 433 that can mesh with the combined toothed disc 4232, and the tooth shape of the connecting toothed disc 433 is approximately a right triangle. The connecting toothed disc 433 and the combined toothed disc 4232 form a pair of clutch gears.

[0073] The toothed structure of the connecting toothed disc 433 is used as an example below. The structure of the connecting toothed disc 4232 is similar to that of the connecting toothed disc 433, and will not be described in detail here. Fig.16 The connecting toothed disc 433 has a first tooth surface 4331 and a second tooth surface 4332 , and the angle between the first tooth surface 4331 and the central axis of the connecting toothed disc 433 is 5 degrees.

[0074] Fig.17A variety of tooth structures are shown in the figure. Figure I shows the most common claw clutch gear in the prior art, which is a rectangular tooth; Figures II to V show triangular teeth. The tooth shape in Figure II is a right triangle, the angle between one side of the tooth shape and the central axis in Figure III is 3 degrees, the angle between one side of the tooth shape and the central axis in Figure IV is 5 degrees, and the angle between one side of the tooth shape and the central axis in Figure V is 15 degrees. The following table shows the comparison of the effects of five tooth structures in fixed gear locking and separation shifting. The following experiments were conducted on the five tooth structures. The motor was installed as a whole on the frame of the same model and switched to the same gear. The locking effect was tested on the same bumpy road section; the separation shifting effect was tested when the motor was stopped and when the motor was running. The test results are as follows:

[0075] Tooth shape Locking effect Split shift effect I very good It is not possible to shift gears while the motor is running. The motor must be completely stopped before shifting gears. II good When the motor is running, there is a sense of frustration when shifting gears, and the tooth surface is damaged III good Smooth gear shifting while the motor is running IV good Smooth gear shifting while the motor is running V generally Smooth gear shifting while the motor is running .

[0076] The tooth shape I is adopted. Since it is a rectangular tooth, it has a good locking effect on the speed change gear 432 when the gear is set. However, when the motor is running, the combined toothed disc 4232 and the connecting toothed disc 433 cannot be separated.

[0077] The tooth profiles II-IV have a good locking effect on the speed gear 432 when setting the gear. According to experiments, the selected gear can still be maintained under the condition that the motor as a whole is vibrated. When tooth profiles III and IV are used, the combined tooth disc 4232 and the connecting tooth disc 433 can be separated from each other when the motor is running, but when tooth profile II is used, forced gear shifting can be successful when the motor is running, but the tooth surface is damaged.

[0078] When the tooth shape V is adopted, the combined toothed disc 4232 and the connecting toothed disc 433 can be smoothly disengaged from each other when the motor is running. However, when the motor as a whole is vibrated, the pedals feel the instantaneous motor loss of force, and the locking effect is general.

[0079] According to the above table, the angle between the first tooth surface 4331 and the central axis of the connecting toothed disc 433 is designed to be 3-5 degrees in this application, which not only ensures the effect of fixed gear locking, but also enables non-stop gear shifting when the motor is running.

[0080] Fig.13 The speed change output assembly 430 shown includes four speed change gears 432 , namely a first speed change gear 4321 , a second speed change gear 4322 , a third speed change gear 4323 and a fourth speed change gear 4324 .

[0081] When the speed change mechanism 400 is working, the shift hub 421 is driven to rotate, and the shift pin 424 is driven to move in the curved groove of the shift hub 421. Specifically, the shift pin 424 in the upper set of shift forks 422 moves in the first curved groove 4211, and the shift pin 424 in the lower set of shift forks 422 moves in the second curved groove 4212. The shift forks 422 can move linearly along the axis of the shift hub 421. The motion state of the two sets of shift forks 422 is realized by the curve design of the first curved groove 4211 and the second curved groove 4212.

[0082] Fig.18 The moving state of the four-speed transmission output assembly 430 is shown. The horizontal axis is the circumferential development length of the shift hub 421, and the vertical axis is the axial length of the shift hub 421. It should be noted that: Fig.18 This is just a schematic diagram. The figure only shows the status of key nodes, and the coordinate spacing is not equal to the actual distance. Fig.18 The middle fold lines aa and bb respectively reflect the directions of the first curved groove 4211 and the second curved groove 4212 , but the actual first curved groove 4211 and the second curved groove 4212 are cam curved grooves with chamfers.

[0083] When the speed change mechanism 400 is working, the speed change motor can be used to drive the shift hub 421 to rotate, the shift pin 424 moves in the curved groove, the shift hub 421 rotates to the node ① position, the shift coupling member 423 located at the top is meshed and connected with the fourth speed gear 4324, and the shift coupling member 423 located at the bottom is in neutral and is not connected with the gear. At this time, the output intermediate shaft 431 rotates to drive the fourth speed gear 4324 to rotate.

[0084] The shift hub 421 continues to rotate and rotates to the node ② position. The shift coupling member 423 located at the top is first separated from the fourth speed gear 4324, and then meshed with the third speed gear 4323. The shift coupling member 423 located at the bottom is still in neutral. At this time, the output intermediate shaft 431 rotates to drive the third speed gear 4323 to rotate.

[0085] The shift hub 421 continues to rotate and rotates to the position of node ③. The shift coupling member 423 located at the top is separated from the third speed gear 4323 and moves to neutral and is not connected to the gear. The shift coupling member 423 located at the bottom is meshed and connected with the second speed gear 4322. At this time, the output intermediate shaft 431 rotates to drive the second speed gear 4322 to rotate.

[0086] The shift hub 421 continues to rotate and rotates to the position of node ④. The upper shift coupling member 423 is still in neutral, and the lower shift coupling member 423 is separated from the second speed gear 4322 first, and then meshed with the first speed gear 4321. At this time, the output intermediate shaft 431 rotates to drive the first speed gear 4321 to rotate.

[0087] The shift hub 421 continues to rotate to the position of node ⑤, and the shift coupling member 423 located below is separated from the first speed gear 4321. At this time, both the upper and lower sets of shift coupling members 423 are not connected to the gear.

[0088] The outer periphery of the fixed-gear boss 4213 is provided with a fixed-gear notch, and the position of the fixed-gear notch corresponds to the position where the curvilinear groove changes in direction, and its position allows a tolerance within a reasonable range. In this embodiment, five notches are provided, and the positions of the notches correspond to the positions of nodes ①-⑤ in the figure, i.e., the positions where the curvilinear groove changes in direction. In theory, the turning point of the aa, bb broken line in the figure is the node where the gears are engaged or separated, but in reality, within a certain range after the shift coupling member 423 and the speed gear 432 begin to separate, the shift coupling member 423 can still drive the speed gear 432 to rotate, so nodes ①-⑤ can deviate from the turning point of the aa, bb broken line in a small range.

[0089] The speed selection assembly 420 includes a fixed gear pin 425, which is fixedly connected to the housing mechanism 100. The fixed gear pin 425 is arranged perpendicular to the shift hub 421. An elastically extended fixed gear piece is arranged at one end of the fixed gear pin 425; for example, a spherical ball is connected to one end of the fixed gear pin 425 by a spring, and the spherical ball can be elastically extended at this time. The fixed gear piece abuts against the outer periphery of the fixed gear boss 4213. When the fixed gear boss 4213 rotates to a certain position, the fixed gear piece pops out and snaps into the corresponding fixed gear recess, playing a role of locking, preventing the situation in which the gear shift hub 421 rotates due to external force during operation and the gear shifting is disengaged. The end of the fixed gear pin 425 away from the fixed gear boss 4213 extends to the outside of the housing mechanism 100.

[0090] In order to adjust the number of different gears, different numbers of speed selection components 420 can be set as needed, and each group of speed selection components 420 can be correspondingly provided with different numbers of shift forks 422 and shift coupling members 423. In this embodiment, two groups of speed selection components 420 are provided, and each group of speed selection components 420 corresponds to two shift forks 422, so that the mid-mounted speed motor can achieve eight-speed shifting.

[0091] Reference Fig.19 The output intermediate shaft 431 is also coaxially provided with a speed change output gear 4320 , which meshes with the middle shaft output gear 230 in the middle shaft mechanism 200 .

[0092] The number of the intermediate gears 412 in the speed change input assembly 410 is the same as the number of the speed change gears 432 in the speed change output assembly 430. The speed change input assembly 410 is provided with four intermediate gears 412, namely, a first intermediate gear 4121, a second intermediate gear 4122, a third intermediate gear 4123 and a fourth intermediate gear 4124. The first intermediate gear 4121 is meshedly connected with the first speed change gear 4321, the second intermediate gear 4122 is meshedly connected with the second speed change gear 4322, the third intermediate gear 4123 is meshedly connected with the third speed change gear 4323, and the fourth intermediate gear 4124 is meshedly connected with the fourth speed change gear 4324; intermediate gears 412 of different diameters are meshedly connected with corresponding speed change gears 432 to realize different transmission ratios between different gears.

[0093] The second outer shell 120 is provided with a plurality of inspection ports, which correspond to the positions of the speed input assembly 410 and the speed selection assembly 420. The housing mechanism 100 further includes a second cover plate 131 and a third cover plate 132. The second cover plate 131 is connected to the second outer shell 120 for shielding the speed selection assembly 420, and the third cover plate 132 is connected to the second outer shell 120 for shielding the speed input assembly 410. During the maintenance phase, the state of the internal structure of the mid-mounted speed motor can be quickly observed by opening the cover plate, and the motor fault position can be quickly located without removing the mid-mounted speed motor from the frame. The fixed gear pin 425 is located outside the housing mechanism 100, and the gear switching problem can be solved by opening the second cover plate 131 and adjusting the fixed gear pin 425.

[0094] The "coaxial", "parallel", "perpendicular" and the like described in this application are all allowed to have tolerance within a reasonable range. The above are all preferred embodiments of this application, and are not intended to limit the protection scope of this application. Therefore, any equivalent changes made based on the structure, shape, and principle of this application should be included in the protection scope of this application.

Claims

1. A mid-mounted variable speed motor, comprising a motor body, characterized in that: It includes a housing mechanism, a central shaft mechanism, a power transmission mechanism and a speed change mechanism, wherein the central shaft mechanism, the power transmission mechanism and the speed change mechanism form a multi-parallel axis structure; wherein, The central axis mechanism is used to input pedal power and output motor assistance; The power transmission mechanism is connected between the motor body and the speed change mechanism; The speed change mechanism includes a speed change input assembly, a speed change selection assembly and a speed change output assembly; wherein, The speed change input assembly includes a plurality of intermediate gears of different diameters, and the plurality of intermediate gears are coaxially arranged to connect the speed change output assembly with the power transmission mechanism; The speed change output assembly is in transmission connection with the middle shaft mechanism, the speed change output assembly includes speed change gears with the same number as the intermediate gears, the multiple speed change gears are coaxially arranged and used for meshing and transmission connection with the corresponding intermediate gears, the speed change output assembly also includes an output intermediate shaft, the speed change gears are sleeved on the output intermediate shaft; The speed selection assembly includes a shift coupling, which reciprocates in the direction of the speed gear axis to switch the transmission relationship between the speed gear and the intermediate gear. The shift coupling is transmission-connected to the output intermediate shaft via a connecting key, and the shift coupling includes a coupling sprocket, wherein the speed gear is provided with a connecting sprocket for meshing and connecting with the coupling sprocket in the direction of the speed gear axis.

2. A mid-mounted variable speed motor according to claim 1, characterized in that: The tooth shape of the combined toothed disc is triangular, and the angle between one tooth surface and the center axis of the combined toothed disc is 3-5 degrees; the tooth shape of the connecting toothed disc is triangular, and the angle between one tooth surface and the center axis of the connecting toothed disc is 3-5 degrees.

3. The mid-mounted variable speed motor according to claim 1, characterized in that: The speed selection assembly also includes a shift hub, a shift fork and a shift pin; wherein, a curved groove is provided on the surface of the shift hub; the shift fork includes a cam sleeve and a coupling sleeve with parallel axes, the cam sleeve is sleeved on the shift hub, the cam sleeve and the shift hub are connected by a shift pin, so that the rotation of the shift hub is converted into linear movement of the cam sleeve, and the shift coupling member is rotatably sleeved in the coupling sleeve.

4. A mid-mounted variable speed motor according to claim 3, characterized in that: The shift forks are provided in plurality, the shift coupling members are provided in the same number as the shift forks and are provided in one-to-one correspondence, and the number of the curved grooves provided on the shift hub is consistent with the number of the shift forks.

5. The mid-mounted variable speed motor according to claim 3, characterized in that: The shift hub is coaxially fixedly connected with a fixing boss, and the fixing boss is circumferentially provided with a fixing recess. The speed selection assembly also includes a fixing pin, one end of which is connected with a fixing member that can be elastically extended, and the fixing member is circumferentially abutted against the fixing boss, and the position of the fixing recess corresponds to the position where the direction of the curved groove changes.

6. The mid-mounted variable speed motor according to claim 1, characterized in that: The shell mechanism includes a first outer shell, a second outer shell and an inner shell; the first outer shell and the second outer shell cooperate to form an internal space, the depth of the internal space of the first outer shell is less than the depth of the internal space of the second outer shell, and the inner shell cooperates with the second outer shell to form a closed space for accommodating a power transmission mechanism.

7. A mid-mounted variable speed motor according to claim 6, characterized in that: The second outer shell is provided with a plurality of inspection openings, the positions of which correspond to the positions of the speed input assembly and the speed selection assembly. The second outer shell is also provided with a receiving cavity for receiving the motor body. The housing structure also includes a cover for shielding the inspection openings and the receiving cavity.

8. The mid-mounted variable speed motor according to claim 1, characterized in that: The speed change output components are provided in a plurality of groups, and the number of the speed change selection components is consistent with the number of the speed change output components.

9. The mid-mounted variable speed motor according to claim 1, characterized in that: The speed change input assembly includes an input intermediate shaft, and the intermediate gear is connected to the input intermediate shaft through a plurality of step positioning members, and the plurality of step positioning members are arranged at intervals along the circumference of the input intermediate shaft, and the step positioning members are divided into a plurality of steps along the axial direction of the intermediate shaft, and different steps have different radial thicknesses, and the end faces of the steps are used to abut against the end faces of the intermediate gears, and the outer peripheral surfaces of the steps are used to abut against the inner rings of the intermediate gears, and keyways are formed between the circumferentially adjacent step positioning members.

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