Bicycle independent derailleur

Abstract

A bicycle independent gearshift includes a box, a toothed disc, a gearshift component and a gearshift handle mounted on a handlebar. The box is fixed at the joint of a frame vertical tube and a rear lower fork, and the toothed disc is mounted on a crank on the left side of the bicycle. A gearshift wheel is arranged at the upper left side of the box and connected with the gearshift handle through a gearshift line. An input wheel is arranged at the lower left side of the box and connected with the toothed disc through a transmission member. An output wheel and a supporting arm are arranged at the right side of the box and connected with a freewheel of the bicycle through a transmission member. The gearshift component is mounted in the box and includes a gearshift gear, a gearshift disc and a gearshift member. The gearshift gear and the gearshift disc are axially engaged to change a transmission ratio. The gearshift member is provided with a buffer structure to ensure the convenience and smoothness of gearshift. The invention has simple structure, low cost and long service life. It is not only suitable for human-powered bicycles and tricycles, but also suitable for pedal driving systems of electric vehicles or moped, and can be used in mechanical gearshift occasions in other fields.

Description

Technical Field

[0001] This invention relates to the transmission mechanism of a bicycle, and more specifically, to an independent gearbox mounted outside the bicycle transmission mechanism. Background Technology

[0002] Bicycles are a convenient and efficient means of transportation, widely used for short-distance commuting, sports, and fitness. As people's living standards improve, the demand for bicycles is becoming increasingly sophisticated. Traditional single-speed bicycles are facing obsolescence due to their inability to adapt to complex road conditions, while multi-speed bicycles are becoming the mainstream consumer choice.

[0003] The core component of a multi-speed bicycle is the gearbox, which is located in the bicycle's transmission mechanism. By switching the gear ratios of the gearbox, riding can be faster and less strenuous.

[0004] Existing bicycle derailleurs are divided into two types: internal derailleurs and external derailleurs. Internal derailleurs are further divided into hub derailleurs and bottom bracket derailleurs.

[0005] The derailleur's shifting components are encapsulated inside the hub of the bicycle's rear wheel, changing the wheel's speed through the meshing of planetary gears. Due to space constraints in the rear wheel hub, this type of derailleur has a relatively complex structure, requires high precision in parts manufacturing, and is difficult to assemble, resulting in a high price and hindering its widespread adoption.

[0006] The bottom bracket derailleur housing is mounted at the bottom bracket of the frame, and the output speed of the chainrings is changed through the transmission between the bottom bracket and the gears inside the housing. Due to the limited space at the bottom bracket of the frame, this type of derailleur also suffers from the same drawbacks as hub derailleurs. In addition, this type of derailleur requires significant modifications to the frame, increasing manufacturing costs.

[0007] An external derailleur consists of a derailleur and multiple crank chainrings and freewheel chainrings of varying sizes. The gear ratio is changed by the chain engaging with chainrings of different tooth counts. This type of derailleur has poor shifting smoothness, the chain is easily damaged, and the derailleur, suspended outside the frame, is highly susceptible to damage from collisions or falls. Furthermore, because its shifting components are exposed, they are easily contaminated by dust and rain, affecting transmission efficiency or causing mechanical failures, and requiring frequent maintenance, which is inconvenient for users.

[0008] In summary, existing bicycle internal and external derailleurs are tightly integrated with the bicycle's transmission components. Due to limitations in component structure and surrounding space, they create performance shortcomings that are difficult to balance. While internal derailleurs are durable and maintenance-free, they are expensive and difficult to repair; external derailleurs, while cheaper and with more gears, are prone to damage and inconvenient to use. Summary of the Invention

[0009] To address the problems of existing bicycle derailleurs, this invention provides a novel bicycle derailleur structure that is independently mounted on the bicycle frame and changes the gear ratio through a closed device, thereby achieving the goals of long lifespan, low cost, maintenance-free operation, and ease of use.

[0010] The technical solution of the present invention is as follows: An independent bicycle derailleur includes a housing, a chainring, a shifting mechanism, and a shift lever mounted on the handlebars. The housing is fixed to the junction of the seat tube and the chainstays. The chainring is mounted on the crank on the left side of the bicycle. A shift wheel is located on the upper left side of the housing, connected to the shift lever via a shift cable. An input wheel is located on the lower left side of the housing, connected to the chainring via a transmission mechanism. An output wheel and a support arm are located on the right side of the housing, connected to the bicycle's freewheel via a transmission mechanism. The shifting mechanism is installed inside the housing and includes several shafts and gears. The ends of the input shaft, output shaft, and shift shaft extend out of the housing. The input wheel, output wheel, and shift wheel are respectively mounted on their corresponding ends, and the shafts are connected to each other via gears.

[0011] The transmission components installed inside the housing include an input shaft, an output shaft, a shift shaft, and a neutral shaft. The input shaft is installed at the bottom of the housing, with a gear at its rear end and a front end extending from the left side of the housing. The input wheel is mounted on this shaft head. The front end of the output shaft is rotatably connected to the input shaft, and a transmission gear is mounted on it. The rear end of the output shaft extends from the right side of the housing, and the output wheel is mounted on this shaft head. The neutral shaft is installed in the middle of the housing, and a neutral shaft gear, a transmission gear, and a shift disc are mounted on it. Both ends of the neutral shaft are rotatably connected to the housing. The shift shaft is installed at the top of the housing, and a shift fork is mounted on it. The front end of the shift shaft extends from the left side of the housing, and the shift wheel is mounted on this shaft head. The gear on the input shaft meshes with the neutral shaft gear, the transmission gear meshes with the transmission gear, the shift disc is axially meshed with the transmission gear, and the shift fork is rotatably connected to the shift disc.

[0012] The transmission component connecting the chainring and the input wheel can be a chain drive, belt drive, or shaft drive, and the chainring and input wheel are a sprocket, pulley, or gear. The transmission component connecting the output wheel and the flywheel can also be a chain drive, belt drive, or shaft drive, and the output wheel and flywheel are also a sprocket, pulley, or gear.

[0013] The housing is equipped with a side cover and a top cover. The side cover facilitates the installation of the transmission components inside the housing, while the top cover facilitates maintenance and adjustment. After removing the top cover, a drive motor can be installed here to achieve electric drive. The shift wheel or shift shaft can be connected to a control motor to achieve electronic shifting or intelligent control.

[0014] The box body can be fixed to the frame riser by using clamps or by welding a fixing plate onto the riser; the box body can be fixed to the frame lower fork by using T-bolts or by welding a fixing seat onto the lower fork.

[0015] The support arm is installed at the bottom of the box and is rotatably connected to the box. The upper part of the support arm is equipped with a spring, and the lower part is equipped with a guide wheel.

[0016] The input shaft and the gear on the shaft are combined or integrated. The output shaft and the transmission gear on the shaft are connected by a key or set screw. The central shaft and the central shaft gear are connected by a key. The central shaft and the speed-changing gear are rotatably connected. The central shaft and the speed-changing disc are axially slidably connected by a guide key.

[0017] The central shaft has several gear shift discs, each with a keyway in its central hole, through holes or concave teeth on both sides, and grooves on its cylindrical surface. The gear shifting gears on the central shaft are composed of several gears with different numbers of teeth, and have protruding pinions or teeth on their sides. The transmission gears on the output shaft are also composed of several gears with different numbers of teeth, including gear sets, tufts, or multi-gear sets.

[0018] The shift shaft has several shift forks, each with a bushing at its top. A curved groove is provided on the cylindrical surface of the bushing. A pin is mounted on the shift shaft within the curved groove and can slide within the groove. A return spring is mounted on the right end of the shift shaft.

[0019] The shifting component includes a buffer structure, which has a protruding plate on one side of the shifting wheel and a groove at one end of the shifting shaft. The protruding plate of the shifting wheel is inserted into the groove of the shifting shaft and can slide radially in the groove. The shifting wheel and the shifting shaft are elastically connected by a spring. This structure is used to improve the smoothness of shifting.

[0020] The independent bicycle derailleur described in this invention has the following advantages compared to existing internal and external bicycle derailleurs: 1. This derailleur is located outside the bicycle transmission mechanism, freeing it from the limitations of transmission components. The housing structure and component layout are more rational, thus reducing material usage, simplifying the mechanical structure, relaxing the precision requirements for component processing, and lowering manufacturing costs.

[0021] 2. The transmission is independently mounted on the frame, with no other parts obstructing it, making it easy to install and maintain.

[0022] 3. The unique shift buffer structure eliminates shifting jamming and shifting issues caused by untimely engagement of the transmission components. It is easy to operate and shift gears smoothly, without any issues such as component damage.

[0023] 4. The transmission components are integrated into the housing, resulting in a compact structure and lightweight design. Furthermore, the housing protects the transmission components, ensuring good lubrication and preventing corrosion from dust and contaminants, thus achieving maintenance-free operation and a long lifespan, giving users peace of mind.

[0024] 5. The gearbox housing has interfaces for installing a drive motor and a control motor, providing technical support for upgrading bicycles to electric drive. If the control motor is connected to the shifting components, electronic or intelligent shifting can be achieved, further improving the riding experience and comfort. Attached Figure Description

[0025] Figure 1 This is a schematic diagram of the installation position of the present invention; Figure 2 yes Figure 1 Rear view of the independent transmission; Figure 3 yes Figure 2 AA section view; Figure 4 yes Figure 3 A schematic diagram of the intermediate speed change plate and speed change gears; Figure 5 yes Figure 3 A partial schematic diagram of the gear shifting mechanism. Detailed Implementation

[0026] The present invention will be further described below with reference to the accompanying drawings: See Figures 1 to 3 The bicycle independent derailleur of the present invention includes a housing 1, a chainring 8, a shifting component, and a shift lever mounted on the handlebars. The housing 1 is fixed at the junction of the frame seat tube 2 and the chainstay 9. The chainring 8 is mounted on the crank 5 on the left side of the bicycle. A shift wheel 11 is provided on the upper left side of the housing 1, which is connected to the shift lever on the handlebars via a shift cable 7. An input wheel 12 is provided on the lower left side of the housing 1, which is connected to the chainring 8 via a transmission component 6. An output wheel 3 and a support arm 10 are provided on the right side of the housing 1, which are connected to the bicycle freewheel via a transmission component 4. The shifting component is installed inside the housing 1 and includes several shafts and gears. The shaft ends of the input shaft 21, shift shaft 23, and output shaft 34 extend out of the housing. The input wheel 12, shift wheel 11, and output wheel 3 are respectively mounted on their corresponding shaft ends, and the shafts are connected to each other via gears.

[0027] See Figure 3The transmission components installed inside housing 1, in addition to the input shaft 21, shift shaft 23, and output shaft 34, also include a central shaft 18. The input shaft 21 is installed at the lower part of housing 1, with a gear 22 at its rear end and the front end extending from the left side of housing 1. The input wheel 12 is mounted on this shaft head. The front end of the output shaft 34 is rotatably connected to the input shaft 21 via a bearing 33. A transmission gear 35 is mounted on the output shaft, and the rear end extends from the right side of housing 1. The output wheel 3 is mounted on this shaft head. The central shaft 18 is installed in the middle of housing 1, and a central shaft gear 20, a shift disc 28, and a shift gear 29 are mounted on it. Both ends of the central shaft are rotatably connected to housing 1 via bearings 32. The shift shaft 23 is installed at the upper part of housing 1, with a shift fork 27 mounted on it. The front end of the shift shaft extends from the left side of housing 1, and the shift wheel 11 is mounted on this shaft head. The input shaft 21 has a gear 22 meshing with the central shaft gear 20, a gear 29 meshing with the transmission gear 35, a gear shift disc 28 axially meshing with the gear 29, and a shift fork 27 rotatably connected to the gear shift disc 28.

[0028] See Figure 1 and Figure 2 The transmission component 6, used to connect the chainring 8 and the input wheel 12, can be a chain drive, belt drive, or shaft drive, and the chainring 8 and input wheel 12 can be a sprocket, pulley, or gear. Similarly, the transmission component 4, used to connect the output wheel 3 and the freewheel, can also be a chain drive, belt drive, or shaft drive, and the output wheel 3 and freewheel can also be a sprocket, pulley, or gear. The above transmission methods can be selected according to the different uses of the bicycle.

[0029] See Figure 3 The gearbox housing 1 is provided with an upper cover 17 and a side cover 37. The side cover 37 is used to facilitate the installation of the gearbox components inside the housing 1, and the upper cover 17 is used to facilitate maintenance and adjustment. After removing the upper cover 17, a drive motor can be installed here to realize electric drive. The shift wheel 11 or shift shaft 23 can be connected to the control motor to realize electronic shifting or intelligent control.

[0030] See Figure 1 and Figure 2 The gearbox 1 can be fixed to the frame seat tube 2 using clamps 15 or by welding a fixing plate onto the seat tube; the gearbox 1 can be fixed to the frame chainstay 9 using T-bolts 16 or by welding a fixing seat onto the chainstay. The clamps 15 and T-bolts 16 are suitable for retrofitting older bicycles, while the welding fixing plate and fixing seat are suitable for new bicycles under construction.

[0031] Let's look again. Figure 1 and Figure 2The support arm 10 is installed at the lower part of the housing 1 and is rotatably connected to the housing 1. A spring 13 is installed at the upper part of the support arm 10, and a guide wheel 14 is installed at the lower part of the support arm 10. This support arm can keep the transmission component 4 in a tensioned state to prevent it from falling off during riding.

[0032] See Figure 3 The input shaft 21 and the gear 22 on the shaft are combined or integrated. The output shaft 34 and the transmission gear 35 on the shaft can be connected by a key 36 or a set screw. The central shaft 18 and the central shaft gear 20 are connected by a key 19. The central shaft 18 and the speed change gear 29 are rotatably connected. The central shaft 18 and the speed change disk 28 are axially slidably connected by a guide key 31.

[0033] See Figure 3 and Figure 4 The central shaft 18 has several gear shift discs 28. Each disc has a keyway 38 in its central hole, through holes 39 or concave teeth on both sides, and grooves 40 on its cylindrical surface. The gear shifting gears 29 on the central shaft 18 are composed of several gears with different numbers of teeth, and have protruding post 41 or protruding teeth on their sides. The transmission gears 35 on the output shaft 34 are also composed of several gears with different numbers of teeth, including gear sets, tufts, or multi-gear sets. The gear shifting gears on the central shaft 18, with increasing tooth counts, mesh with the transmission gears on the output shaft 34, with decreasing tooth counts.

[0034] Let's look again. Figure 3 There are several shift forks 27 on the shift shaft 23. The top of the shift fork 27 is provided with a bushing 24. A curved groove 26 is provided on the cylindrical surface of the bushing. A pin 25 is installed on the shift shaft in the curved groove 26, and the pin 25 can slide in the curved groove 26. A return spring 30 is installed at the right end of the shift shaft 23.

[0035] See Figure 5 The shifting mechanism incorporates a buffer structure. This structure consists of a protruding plate 42 on one side of the shift wheel 11 and a groove 43 at one end of the shift shaft 23. The protruding plate 42 of the shift wheel is inserted into the groove 43 of the shift shaft and can slide radially within the groove 43. The shift wheel and shift shaft are elastically connected by a spring 44. This structure prevents shifting jams or breakage of the shift cable due to the shift disc and gears not being in the meshing position. The spring's buffering effect ensures automatic engagement of the meshing components, improving the smoothness of shifting.

[0036] The independent bicycle gearbox of the present invention has a simple structure, low cost and long service life. It is not only suitable for human-powered bicycles and tricycles, but also for pedal drive systems of electric vehicles or electric bicycles, and can also be used in mechanical gear shifting applications in other fields.

Claims

1. A bicycle independent derailleur, comprising a housing, a chainring, a shifting component, and a shift lever mounted on the handlebars, characterized in that: The gearbox is fixed to the junction of the frame seat tube and the chainstay. The chainring is mounted on the crank on the left side of the bicycle. A shift wheel is located on the upper left side of the gearbox, which is connected to the shift lever via a shift cable. An input wheel is located on the lower left side of the gearbox, which is connected to the chainring via a transmission component. An output wheel and a support arm are located on the right side of the gearbox, which are connected to the bicycle's freewheel via a transmission component. The gearbox assembly is installed inside the gearbox and includes several shafts and gears. The ends of the input shaft, output shaft, and shift shaft extend out of the gearbox. The input wheel, output wheel, and shift wheel are respectively mounted on their corresponding ends, and the shafts are connected to each other via gears.

2. The independent bicycle derailleur according to claim 1, characterized in that: The transmission components installed inside the housing include an input shaft, an output shaft, a shift shaft, and a neutral shaft. The input shaft is installed at the bottom of the housing, with a gear at its rear end and a front end extending from the left side of the housing. The input wheel is mounted on this shaft head. The front end of the output shaft is rotatably connected to the input shaft, and a transmission gear is mounted on it. The rear end of the output shaft extends from the right side of the housing, and the output wheel is mounted on this shaft head. The neutral shaft is installed in the middle of the housing, and a neutral shaft gear, a transmission gear, and a shift disc are mounted on it. Both ends of the neutral shaft are rotatably connected to the housing. The shift shaft is installed at the top of the housing, and a shift fork is mounted on it. The front end of the shift shaft extends from the left side of the housing, and the shift wheel is mounted on this shaft head. The gear on the input shaft meshes with the neutral shaft gear, the transmission gear meshes with the transmission gear, the shift disc is axially meshed with the transmission gear, and the shift fork is rotatably connected to the shift disc.

3. The independent bicycle derailleur according to claim 1, characterized in that: The transmission component connecting the chainring and the input wheel can be a chain drive, belt drive, or shaft drive, and the chainring and input wheel are a sprocket, pulley, or gear. The transmission component connecting the output wheel and the flywheel can also be a chain drive, belt drive, or shaft drive, and the output wheel and flywheel are also a sprocket, pulley, or gear.

4. The independent bicycle derailleur according to claim 1, characterized in that: The housing is equipped with a side cover and a top cover. The side cover facilitates the installation of the transmission components inside the housing, while the top cover facilitates maintenance and adjustment. After removing the top cover, a drive motor can be installed here to achieve electric drive. The shift wheel or shift shaft can be connected to a control motor to achieve electronic shifting or intelligent control.

5. The independent bicycle derailleur according to claim 1, characterized in that: The box body can be fixed to the frame riser by using clamps or by welding a fixing plate onto the riser; the box body can be fixed to the frame lower fork by using T-bolts or by welding a fixing seat onto the lower fork.

6. The bicycle independent derailleur according to claim 1, characterized in that: The support arm is installed at the bottom of the box and is rotatably connected to the box. The upper part of the support arm is equipped with a spring, and the lower part is equipped with a guide wheel.

7. The independent bicycle derailleur according to claim 2, characterized in that: The input shaft and the gear on the shaft are combined or integrated. The output shaft and the transmission gear on the shaft are connected by a key or set screw. The central shaft and the central shaft gear are connected by a key. The central shaft and the speed-changing gear are rotatably connected. The central shaft and the speed-changing disc are axially slidably connected by a guide key.

8. The independent bicycle derailleur according to claim 2, characterized in that: The central shaft has several gear shift discs, each with a keyway in its central hole, through holes or concave teeth on both sides, and grooves on its cylindrical surface. The gear shifting gears on the central shaft are composed of several gears with different numbers of teeth, and have protruding pinions or teeth on their sides. The transmission gears on the output shaft are also composed of several gears with different numbers of teeth, including gear sets, tufts, or multi-gear sets.

9. The independent bicycle derailleur according to claim 2, characterized in that: The shift shaft has several shift forks, each with a bushing at its top. A curved groove is provided on the cylindrical surface of the bushing. A pin is mounted on the shift shaft within the curved groove and can slide within the groove. A return spring is mounted on the right end of the shift shaft.

10. The bicycle independent derailleur according to claim 2, characterized in that: The shifting component includes a buffer structure, which has a protruding plate on one side of the shifting wheel and a groove at one end of the shifting shaft. The protruding plate of the shifting wheel is inserted into the groove of the shifting shaft and can slide radially in the groove. The shifting wheel and the shifting shaft are elastically connected by a spring. This structure is used to improve the smoothness of shifting.

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