Electrically variable transmission bicycle mid-drive internal gear box

Abstract

A kind of electric variable-speed bicycle inner hub gear box, its technology belongs to electric variable-speed technology in the field of bicycle inner hub gear box, the crankshaft of bicycle inner hub gear box is rotating state, so that the gear shifting mechanism of inner hub gear box becomes complex, the crankshaft of gear box of the technical solution is hollow structure, electric variable-speed mechanism is installed in the inner hole of crankshaft, motor stator is rotationally connected with rotating crankshaft, motor rotor is rotationally connected with variable-speed power transmission assembly, in non-variable speed time, electric variable-speed mechanism is synchronous with crankshaft rotation;Gear shifting when, variable-speed remote control handlebar assembly on bicycle handlebar sends remote control signal, the controller of motor receives remote control signal, and drives motor rotor to rotate, so that motor rotor rotates a set angle relative to motor stator, so that variable-speed power transmission assembly, gear shifting mechanism execution assembly generates circumferential, axial, radial displacement relative to rotating crankshaft, realizes variable-speed function.

Description

Technical Field

[0001] An electric shifting bicycle gearbox with internal transmission, the technology of which belongs to the field of bicycle gearboxes with internal transmission, specifically related to electric shifting technology of bicycle gearboxes with internal transmission. Background Technology

[0002] The crankshaft of the gearbox inside the bicycle's bottom bracket is in a rotating state, which means that the manual or electric shifting mechanism of the gearbox inside the bicycle's bottom bracket needs to go through a differential mechanism for power conversion, thus making the shifting mechanism of the gearbox inside the bicycle's bottom bracket complex. Summary of the Invention

[0003] An electric-shifting bicycle bottom bracket internal gearbox is characterized by: a hollow crankshaft in the electric-shifting bicycle bottom bracket internal gearbox; an electric shifting mechanism assembly installed in the inner hole of the crankshaft; wherein the motor stator in the electric shifting mechanism is anti-rotationally connected to the rotating crankshaft, and the motor stator rotates synchronously with the crankshaft during operation; and the motor rotor is anti-rotationally connected to the shifting power transmission component. In the non-shifting state, the motor stator, motor rotor, and the shifting power transmission component, shifting mechanism execution component, and motor battery assembly in the electric shifting mechanism rotate synchronously with the rotating crankshaft. In the shifting state, a remote control signal is emitted through a shifting remote control assembly installed on the bicycle handlebars. The motor controller receives the remote control signal and drives the motor rotor to rotate through a motor driver and encoder, causing the motor rotor to rotate relative to the motor stator by a set angle. This causes the shifting power transmission component and the shifting mechanism execution component to produce circumferential, axial, and radial displacements relative to the rotating crankshaft, thereby realizing the shifting function.

[0004] An electric shifting bicycle bottom bracket internal gearbox, characterized in that: an electric shifting bicycle bottom bracket internal gearbox includes a gearbox housing assembly, a gearbox power transmission mechanism assembly, a gearbox electric shifting mechanism assembly, and a shifting remote control handle assembly.

[0005] An internal gearbox for an electric-shifting bicycle is characterized by: an internal gearbox housing assembly comprising a gearbox housing, a left end cover assembly, a right end cover assembly, and gearbox housing bolts; the gearbox housing is a hollow cylindrical structure, its outer periphery being fixedly connected to the bicycle frame; the left end cover assembly and the right end cover assembly are connected to the gearbox housing via gearbox housing bolts to form a whole with a cylindrical internal space; and the left end cover assembly and the right end cover assembly are provided with bearings and sealing rings at corresponding locations.

[0006] An electric-shifting bicycle gearbox with an internal transmission on the bottom bracket, characterized in that: the power transmission mechanism assembly of the gearbox is installed in the cylindrical internal space of the gearbox housing assembly, and the power transmission mechanism assembly of the gearbox includes a crankshaft assembly and a transition gear assembly.

[0007] The crankshaft assembly is supported at the center of the gearbox by bearings in the left and right end cover assemblies of the gearbox. The crankshaft assembly can rotate freely, while being limited radially and axially.

[0008] The crankshaft assembly includes a crankshaft, an input stage center gear, an output sleeve assembly, and an electric shifter assembly. A set of input stage center gears is fitted onto the middle section of the crankshaft's outer periphery, allowing for selective transmission of multiple gear input power. The inner bore of the input stage center gear has involute splines, enabling selective engagement with corresponding shift sliders. The middle section of the crankshaft has a set of radial through holes corresponding to the input stage center gears, and a set of shift sliders is installed within these radial through holes.

[0009] The right end of the crankshaft outer circumference is fitted with an output sleeve assembly via a one-way bearing. The outer circumference of the left end of the output sleeve assembly is fixedly connected to the center gear of the output stage. The middle section of the output sleeve is supported on the gearbox housing assembly via a bearing in the right end cover assembly of the gearbox. The output sleeve assembly can rotate freely in both directions relative to the gearbox housing assembly and can rotate freely clockwise relative to the crankshaft. The first gear of the gearbox is a direct drive. The power transmission route is crankshaft, one-way bearing, output sleeve assembly.

[0010] There are three sets of transition gear assemblies, evenly distributed circumferentially around the outer periphery of the crankshaft assembly. These assemblies are supported in designated positions by bearings in the left and right end cover assemblies of the gearbox. Each transition gear assembly includes a transition spline shaft, a transition spline sleeve, an input stage transition gear, and an output stage transition gear. Bearing mounting positions are provided at both ends of the transition spline shaft. The left section of the transition spline shaft houses the higher-grade input stage transition gear, while the right section houses the transition spline sleeve, which has splines both inside and outside. There is one set of input stage transition gears, whose outer periphery meshes with the corresponding input stage center gear. The holes have splines, which are respectively fitted onto the transition spline shaft and the transition spline sleeve. There is one transition gear in the output stage, which is fitted onto the right end of the transition spline sleeve and meshes with the center gear of the output stage of the output sleeve assembly. The transition gear assembly is assembled as a whole and rotates synchronously during operation. In the three sets of transition gear assemblies, the transition gears of the input stage and the transition gears of the output stage mesh with the corresponding center gears of the input stage and the output stage simultaneously. During operation, the center gears of the input stage and the center gears of the output stage of the corresponding gear have 3 sets of tooth profiles meshing simultaneously, and the corresponding transition gear assembly has 3 transition gears of the input stage and 3 transition gears of the output stage working simultaneously.

[0011] The crankshaft has a hollow structure, and an electric transmission assembly is installed in the central hole of the crankshaft.

[0012] An electric shifting bicycle bottom bracket internal gearbox, characterized in that: an electric shifting mechanism for the bicycle bottom bracket internal gearbox includes an electric shifting assembly and a shifting remote control handle assembly.

[0013] The shift remote control assembly is installed on the bicycle handlebars. Inside the shift remote control assembly are a button battery, a remote control transmitter, and a control board. On the outside of the shift remote control assembly are a gear display panel, a gear up button, and a gear down button. By operating the corresponding gear button, a gear change signal is transmitted.

[0014] An electric transmission assembly includes a transmission motor assembly, a transmission power transmission assembly, a transmission mechanism actuation assembly, and a battery assembly for the transmission motor.

[0015] The variable speed motor assembly includes a motor stator, motor rotor, motor encoder, motor driver, and motor controller. The variable speed motor has a hollow structure with power and control wires threaded through the central hole. The variable speed motor assembly is installed on the left end inside the crankshaft. The motor encoder, motor driver, and motor controller are connected to the motor stator via bolts and insulating sleeves. The outer circumference of the motor stator is connected to the inner circumference of the crankshaft via a semi-circular key to prevent rotation. A left end cover is provided on the left end of the crankshaft, which serves to seal and restrict the axial position of the variable speed motor stator. The motor rotor is connected to the variable speed power transmission assembly to prevent rotation. The motor controller has a remote control signal receiving function.

[0016] The variable speed power transmission assembly includes a trapezoidal lead screw, a trapezoidal nut, a trapezoidal lead screw bearing, a bearing retaining ring, and a sealing ring. The assembly is installed in the middle section inside the crankshaft. The left end of the trapezoidal lead screw is connected to the motor rotor for anti-rotation. The right end of the trapezoidal lead screw is supported on the inner circumference of the crankshaft by a bearing, and the axial displacement of the lead screw is restricted by the bearing retaining ring. The trapezoidal lead screw is a hollow structure. A trapezoidal nut is fitted around the outer circumference of the lead screw. The outer circumference of the trapezoidal nut has a semi-circular key, which fits into a semi-circular groove on the inner circumference of the crankshaft, restricting the rotation of the nut relative to the crankshaft, allowing only axial movement. Except for the semi-circular key, the outer circumference of the nut is circular and fitted onto the inner circumference of the crankshaft. The inner circumference of the nut has a trapezoidal threaded hole that mates with the trapezoidal lead screw. Tapered surfaces are provided at both ends of the outer circumference of the nut to drive the variable speed slider, causing it to move radially.

[0017] The transmission mechanism actuator includes a set of transmission sliders installed in corresponding radial through holes of the crankshaft. A set of wire springs ensures that, in the non-operating state, the outer circumference of the transmission sliders is circular with the outer circumference of the crankshaft. The axial and circumferential directions of the transmission sliders are confined within the radial through holes of the crankshaft. The outer circumference of the transmission sliders is an involute spline, and the inner circumference is an arc surface with the same diameter as the outer circumference of the trapezoidal nut. The inner circumference of the transmission sliders has tapered ends to receive the driving force of the trapezoidal nut. In the non-operating state, the outer circumference of the transmission sliders is circular with the crankshaft, and the inner diameter is smaller than the inner diameter of the crankshaft. When the transmission sliders enter the operating state, the rotor of the motor... The linkage trapezoidal lead screw drives the trapezoidal nut to generate axial displacement, which in turn drives the speed change slider through the conical surface of the trapezoidal nut, causing it to move radially outward. The involute spline on the outer circumference of the speed change slider engages with the inner involute spline of the central gear of the input stage, which is fitted around the crankshaft. The inner circumferential surface of the speed change slider contacts the outer circumferential surface of the trapezoidal nut. When the speed change slider disengages, the motor rotor, in conjunction with the trapezoidal lead screw, drives the trapezoidal nut to overcome the frictional force between the speed change slider and the trapezoidal nut, generating axial displacement. The radial pressure generated by the inner involute spline of the central gear of the input stage through the involute spline on the outer circumferential surface of the speed change slider causes the speed change slider to move radially inward, thus disengaging from the engagement state.

[0018] The battery assembly of the variable speed motor includes a battery, a power cord, and a battery holder. The battery assembly is installed at the right end inside the crankshaft. The power cord is connected to the variable speed motor controller through the central hole of the trapezoidal lead screw and the central hole of the variable speed motor. The battery holder has an end cap sealing function and fixes the battery inside the crankshaft. Attached Figure Description

[0019] Figure 1 This is an isometric drawing of the gearbox assembly within the central shaft of the electric transmission.

[0020] Figure 2 This is an isometric drawing of the gearbox housing assembly inside the central shaft of the electric transmission.

[0021] Figure 3 This is a sectional view of the gearbox assembly inside the electric transmission shaft.

[0022] Figure 4 This is an isometric drawing of the gearbox transmission mechanism assembly within the central shaft of the electric transmission.

[0023] Figure 5 This is a sectional view of the crankshaft assembly of the gearbox inside the electric transmission shaft.

[0024] Figure 6 This is a cross-sectional view of the output sleeve assembly of the gearbox inside the central shaft of the electric transmission.

[0025] Figure 7 This is a cross-sectional view of the gearbox transition gear assembly inside the central shaft of the electric transmission.

[0026] Figure 8 This is a cross-sectional view of the electric transmission assembly inside the gearbox on the electric transmission shaft. Detailed Implementation

[0027] This technology can design an electric-driven bicycle gearbox with 5 to 11 gears. The specific implementation of the technical solution is an 11-speed electric-driven bicycle gearbox with an internal gearbox. The gearbox or electric gearbox mentioned below is the 11-speed electric-driven bicycle gearbox with an internal gearbox.

[0028] Figure 2 This is an isometric drawing of the gearbox housing assembly inside the electric transmission's bottom bracket. Serial number 1 is the right end cover assembly of the gearbox, serial number 2 is the gearbox housing, serial number 3 is the left end cover assembly of the gearbox, serial number 4 is the gearbox housing bolt, and serial number 5 is the gearbox lubrication bolt. The gearbox housing is fixedly connected to the bicycle frame. The left end cover assembly and the right end cover assembly of the gearbox are connected to the gearbox housing by the gearbox housing bolts to form a whole with a cylindrical internal space. The left end cover assembly and the right end cover assembly of the gearbox are equipped with bearings and seals at corresponding positions.

[0029] Figure 3 This is a sectional view of the gearbox assembly inside the electric transmission shaft. Item 1 is the gearbox housing assembly, item 2 is the gearbox power transmission mechanism assembly, item 3 is the gearbox crankshaft assembly, and item 4 is the gearbox electric transmission mechanism assembly. The gearbox power transmission mechanism assembly is installed in the cylindrical internal space of the gearbox housing assembly. The gearbox crankshaft assembly is installed in the center position inside the gearbox housing assembly. The gearbox crankshaft is a hollow structure, and the gearbox electric transmission mechanism assembly is installed inside the central hole of the crankshaft.

[0030] Figure 4 This is an isometric drawing of the transmission mechanism assembly of the gearbox inside the electric transmission shaft. Serial number 1 is the crankshaft assembly, serial number 2 is the transition gear assembly, and serial number 3 is the output sleeve assembly. There are three sets of transition gear assemblies, which are evenly distributed around the outer periphery of the crankshaft assembly. The output sleeve assembly is fitted onto the outer periphery of the right end of the crankshaft assembly.

[0031] Figure 5 This is a sectional view of the crankshaft assembly of the electric transmission within the central shaft. Serial number 1 is the crankshaft, serial number 2 is the input stage center gear, serial number 3 is the output sleeve assembly, and serial number 4 is the electric transmission mechanism assembly. There are 10 input stage center gears. The input stage center gears of the 11th gear to the 2nd gear are sequentially fitted onto the outer circumference of the crankshaft from left to right. The inner bore of the input stage center gears has involute splines.

[0032] Figure 6This is a sectional view of the output sleeve assembly of the gearbox inside the electric transmission shaft. Item 1 is the output sleeve, item 2 is the center gear of the output stage, item 3 is the one-way bearing, item 4 is the crankshaft bearing, and item 5 is the crankshaft seal. The center gear of the output stage is fixedly connected to the output sleeve. The output sleeve is responsible for the power output from gear 1 to gear 11, and the center gear of the output stage is responsible for the power output transmission from gear 2 to gear 11. Gear 1 is a direct drive, and its power transmission route is: crankshaft, one-way bearing, output sleeve.

[0033] Figure 7 This is a sectional view of the gearbox transition gear assembly inside the electric transmission shaft. Item 1 is the transition spline shaft, item 2 is the transition spline sleeve, item 3 is the input stage transition gear, and item 4 is the output stage transition gear. Bearing mounting positions are provided at both ends of the transition spline shaft. Splines are provided on both the inner and outer circumferences of the transition spline sleeve. The inner bores of the input stage and output stage transition gears have splines. The 11th, 10th, and 9th gears of the input stage transition gears and the transition spline sleeve are sequentially fitted onto the outer circumference of the transition spline shaft from left to right. The 8th to 2nd gears of the input stage transition gears and the output stage transition gear are sequentially fitted onto the outer circumference of the transition spline sleeve from left to right. All parts of the gearbox transition gear assembly are assembled into a single structure via splines, rotating synchronously during operation.

[0034] Figure 8 This is a sectional view of the electric transmission assembly within the gearbox on the center shaft of the electric transmission. Item 1 is the crankshaft, item 2 is the motor stator, item 3 is the motor rotor, item 4 is the motor encoder, item 5 is the motor driver, item 6 is the motor controller, item 7 is the left end cover of the crankshaft, item 8 is a bolt, item 9 is a spacer sleeve, item 10 is the left end seal of the trapezoidal lead screw, item 11 is the trapezoidal lead screw, item 12 is the trapezoidal lead screw bearing, item 13 is the trapezoidal lead screw retaining ring, item 14 is the right end seal of the trapezoidal lead screw, item 15 is the motor battery, item 16 is the battery holder, item 17 is the power cord, and item 18 is... The trapezoidal nut, number 19 is the gear shift slider, number 20 is the wire spring, the crankshaft is a hollow structure, the electric gear shift assembly is installed inside the central hole of the crankshaft, the gear shift remote control assembly of the electric gear shift mechanism (not shown in the figure), the motor stator is connected to the crankshaft to resist rotation via a semi-circular key on the outer periphery, the motor encoder, motor driver, and motor controller are connected to the motor stator with bolts and a insulating sleeve, the motor rotor is connected to the trapezoidal lead screw to resist rotation, the motor battery is fixedly connected to the crankshaft via a battery holder, both the motor and the trapezoidal lead screw are hollow structures, and the battery power cable is connected to the motor controller through the inner hole of the trapezoidal lead screw.

[0035] The power transmission route for gears 9 through 11 in the 11-speed gearbox of an electric bicycle is as follows: crankshaft, shift slider, input stage center gear, input stage transition gear, transition spline shaft, transition spline sleeve, output stage transition gear, output stage center gear, output sleeve. The power transmission route for gears 2 through 8 does not pass through the transition spline shaft.

[0036] The electric transmission power route of the 11-speed internal gearbox of an electric bicycle is as follows: the remote control transmits the gear shift signal, the motor controller receives the signal and sends a motor drive signal, the motor rotor rotates by a set angle, the trapezoidal lead screw rotates by the same angle, the trapezoidal nut moves axially by a set step, the corresponding gear slider enters the engagement state, and the corresponding input stage center gear enters the working state.

[0037] List of gears in an 11-speed internal derailleur on an electric bicycle: Gear ratio differential speed range 1st gear 1:1 2nd gear 1: 1.165 16.5% 3rd gear 1: 1.356 16.4% 4th gear 1:1.581 16.6% 5th gear 1: 1.849 16.7% 6th gear 1:2.176 17.7% 7th gear 1:2.58 18.6% 8 gears 1:3.095 20.0% 9 gears 1:3.77 21.8% 10th gear 4.703 24.7% 11th gear, 6.064, 28.9%, 606%

Claims

1. An internal gearbox for the bottom bracket of an electric-powered bicycle, characterized in that: The crankshaft of the gearbox inside the bottom bracket of an electric shifter bicycle has a hollow structure. The electric shifting mechanism assembly is installed in the inner hole of the crankshaft. The motor stator in the electric shifting mechanism is anti-rotationally connected to the rotating crankshaft. When working, the motor stator rotates synchronously with the crankshaft. The motor rotor is anti-rotationally connected to the shifting power transmission component. In the non-shifting state, the motor stator, motor rotor, shifting power transmission component, shifting mechanism execution component, and motor battery assembly in the electric shifting mechanism rotate synchronously with the rotating crankshaft. In the shifting state, the shifting remote control assembly installed on the bicycle handlebars sends a remote control signal. The motor controller receives the remote control signal and drives the motor rotor to rotate through the motor driver and encoder. This causes the motor rotor to rotate at a set angle relative to the motor stator, thereby causing the shifting power transmission assembly and the shifting mechanism execution assembly to produce circumferential, axial, and radial displacements relative to the rotating crankshaft, thus realizing the shifting function. The electric shifting bicycle gearbox includes a gearbox housing assembly, a gearbox power transmission mechanism assembly, a gearbox electric shifting mechanism assembly, and a shifting remote control handlebar assembly.

2. A bicycle gearbox with electric shifting according to claim 1, characterized in that: The gearbox housing assembly includes a gearbox housing, a left end cover assembly, a right end cover assembly, and gearbox housing bolts. The gearbox housing is a hollow cylindrical structure, and its outer periphery is fixedly connected to the bicycle frame. The left end cover assembly and the right end cover assembly are connected to the gearbox housing by the gearbox housing bolts to form a whole with a cylindrical internal space. The left end cover assembly and the right end cover assembly are provided with bearings and seals at corresponding locations.

3. A bicycle gearbox with electric shifting according to claim 1, characterized in that: The power transmission mechanism assembly of the gearbox is installed in the cylindrical internal space of the gearbox housing assembly. The power transmission mechanism assembly of the gearbox includes a crankshaft assembly and a transition gear assembly. The crankshaft assembly is supported at the center of the gearbox by bearings in the left and right end cover assemblies of the gearbox. The crankshaft assembly can rotate freely in the circumferential direction, while being limited in the radial and axial directions. The crankshaft assembly includes a crankshaft, an input stage center gear, an output sleeve assembly, and an electric transmission assembly. A set of input stage center gears is fitted onto the outer periphery of the crankshaft, selectively transmitting input power at multiple gears. The inner bore of the input stage center gear has involute splines that selectively mesh with corresponding transmission sliders. The middle section of the crankshaft has a set of radial through holes corresponding to the input stage center gears, and a set of transmission sliders is installed in the radial through holes of the crankshaft. The right end of the crankshaft outer periphery is fitted with an output sleeve assembly via a one-way bearing. The outer periphery of the left end of the output sleeve assembly is fixedly connected to the center gear of the output stage. The middle section of the output sleeve is supported on the gearbox housing assembly via a bearing in the right end cover assembly of the gearbox. The output sleeve assembly can rotate freely in both directions relative to the gearbox housing assembly and can rotate freely clockwise relative to the crankshaft. The first gear of the gearbox is a direct drive. The power transmission route is crankshaft, one-way bearing, and output sleeve assembly.

4. The power transmission mechanism assembly of the gearbox according to claim 3, comprising a transition gear assembly, characterized in that: There are three sets of transition gear assemblies, evenly distributed circumferentially around the outer periphery of the crankshaft assembly. These assemblies are supported in designated positions by bearings in the left and right end cover assemblies of the gearbox. Each transition gear assembly includes a transition spline shaft, a transition spline sleeve, an input stage transition gear, and an output stage transition gear. Bearing mounting positions are provided at both ends of the transition spline shaft. The left section of the transition spline shaft houses the high-end input stage transition gear, while the right section houses the transition spline sleeve. The transition spline sleeve has splines on both its inner and outer surfaces. There is one set of input stage transition gears, whose outer periphery meshes with the corresponding input stage center gear. The holes have splines, which are respectively fitted onto the transition spline shaft and the transition spline sleeve. There is one transition gear in the output stage, which is fitted onto the right end of the transition spline sleeve and meshes with the center gear of the output stage of the output sleeve assembly. The transition gear assembly is assembled as a whole and rotates synchronously during operation. In the three sets of transition gear assemblies, the transition gears of the input stage and the transition gears of the output stage mesh with the corresponding center gears of the input stage and the center gears of the output stage at the same time. During operation, the center gears of the input stage and the center gears of the output stage of the corresponding gear have 3 sets of tooth profiles meshing at the same time, and the corresponding transition gear assembly has 3 transition gears of the input stage and 3 transition gears of the output stage working at the same time. The crankshaft is a hollow structure, and an electric transmission assembly is installed in the central hole of the crankshaft.

5. A bicycle gearbox with electric shifting according to claim 1, characterized in that: An electric shifting mechanism for a bicycle bottom bracket internal gearbox includes an electric shifting assembly and a shifting remote control handle assembly. The aforementioned gear shift remote control assembly is installed on the bicycle handlebars. The internal components of the gear shift remote control assembly include a button battery, a remote control transmitter, and a control board. The external components of the gear shift remote control assembly are equipped with a gear display panel, a gear increase button, and a gear decrease button. By operating the corresponding gear buttons, a gear change signal is transmitted.

6. The electric transmission assembly according to claim 1, characterized in that: Including variable speed motor assembly, variable speed power transmission assembly, variable speed mechanism actuation assembly, and variable speed motor battery assembly; The variable speed motor assembly includes a motor stator, a motor rotor, a motor encoder, a motor driver, and a motor controller. The variable speed motor has a hollow structure with power and control wires threaded through the central hole. The variable speed motor assembly is installed on the left end of the crankshaft inner hole. The motor encoder, motor driver, and motor controller are connected to the motor stator via bolts and a insulating sleeve. The outer circumference of the motor stator is connected to the inner circumference of the crankshaft via a semi-circular key to prevent rotation. A left end cover is provided on the left end of the crankshaft. The left end cover has a sealing function and restricts the axial position of the variable speed motor stator. The motor rotor is connected to the variable speed power transmission assembly to prevent rotation. The motor controller has a remote control signal receiving function. The aforementioned variable speed power transmission assembly includes a trapezoidal lead screw, a trapezoidal nut, a trapezoidal lead screw bearing, a bearing retaining ring, and a sealing ring. The variable speed power transmission assembly is installed in the middle section of the inner hole of the crankshaft. The left end of the trapezoidal lead screw is connected to the motor rotor for anti-rotation. The right end of the trapezoidal lead screw is supported on the inner circumference of the crankshaft hole by a bearing, and the axial displacement of the trapezoidal lead screw is restricted by the bearing retaining ring. The trapezoidal lead screw is a hollow structure. A trapezoidal nut is fitted on the outer circumference of the trapezoidal lead screw. The outer circumference of the trapezoidal nut has a semi-circular key, which is fitted into a semi-circular groove on the inner circumference of the crankshaft to restrict the rotation of the trapezoidal nut relative to the crankshaft, so that the trapezoidal nut can only move axially relative to the crankshaft. Except for the semi-circular key, the outer circumference of the trapezoidal nut is a circular surface and is fitted into the inner hole of the crankshaft. The inner circumference of the trapezoidal nut is a trapezoidal threaded hole that mates with the trapezoidal lead screw. The two ends of the outer circumference of the trapezoidal nut are provided with tapered surfaces for driving the variable speed slider to produce radial movement. The aforementioned gear shift mechanism actuator includes a set of gear shift sliders installed in corresponding radial through holes of the crankshaft. A set of wire springs ensures that, in the non-operating state, the outer circumference of the gear shift sliders is circular with the outer circumference of the crankshaft. The axial and circumferential directions of the gear shift sliders are confined within the radial through holes of the crankshaft. The outer circumference of the gear shift sliders is an involute spline, and the inner circumference is an arc surface with the same diameter as the outer circumferential surface of the trapezoidal nut. The inner circumferential surface of the gear shift sliders has tapered ends to receive the driving force of the trapezoidal nut. In the non-operating state, the outer circumference of the gear shift sliders is circular with the crankshaft, and the inner diameter is smaller than the inner diameter of the crankshaft. When the gear shift sliders enter the operating state, they are driven by the motor... The rotor-driven trapezoidal lead screw drives the trapezoidal nut to generate axial displacement, which in turn drives the speed change slider through the conical surface of the trapezoidal nut, causing it to move radially outward. The involute spline on the outer circumference of the speed change slider engages with the inner involute spline of the central gear of the input stage, which is fitted around the crankshaft. The inner circumference of the speed change slider presses against the outer circumference of the trapezoidal nut. When the speed change slider disengages, the rotor-driven trapezoidal lead screw drives the trapezoidal nut to overcome the frictional force between the speed change slider and the trapezoidal nut, generating axial displacement. The radial pressure generated by the inner involute spline of the central gear of the input stage through the involute spline on the outer circumference of the speed change slider causes the speed change slider to move radially inward, thus disengaging from the engagement state. The battery assembly of the variable speed motor includes a battery, a power cord, and a battery holder. The battery assembly is installed at the right end of the crankshaft inner hole. The power cord is connected to the variable speed motor controller through the central hole of the trapezoidal lead screw and the central hole of the variable speed motor. The battery holder has an end cap sealing function and fixes the battery to the crankshaft inner hole.

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