Frictionally rotating lock-up disconnect transmission

Abstract

The application discloses a friction rotation locking separation transmission, and relates to the technical field of bicycles.The transmission comprises a friction gear shifting disc, a first chain disc, a second chain disc, a third chain disc and a crank.The crank is sequentially penetrated through the third chain disc and the second chain disc through a rotating shaft and is fixedly connected with the first chain disc.The second chain disc, the third chain disc and the crank are connected through bearings.Each chain disc is separately connected with a chain.The crank is provided with a linkage mechanism.The friction gear shifting disc controls the second chain disc and the third chain disc through the linkage mechanism.The friction gear shifting disc is in contact with a gear shifting piece.The friction gear shifting disc comprises a first rotating disc and a second rotating disc which are rotationally connected.A guide groove with a V-shaped limiting block is arranged on the first rotating disc.A rotating rod with a supporting rod is arranged on the second rotating disc.The supporting rod is slidably arranged in the guide groove.The application can complete gear shifting without pulling the chain, avoids the problems of chain disconnection and jamming, has a simple and compact structure, is easy and labor-saving to operate and has low manufacturing cost.

Description

Technical Field

[0001] This invention relates to the field of bicycle technology, and more specifically to a friction-rotational locking disengagement gearbox. Background Technology

[0002] Bicycles are widely used in daily life as a green mode of transportation. To adapt to different road conditions and riding needs, bicycles are usually equipped with derailleurs. Traditional bicycle derailleurs mainly use front and rear derailleurs in conjunction with derailleurs to achieve multi-speed shifting. The derailleurs switch the chain between different sized chainrings or freewheels, thereby changing the gear ratio. This type of gear shifting has the following problems in practical use: First, during gear shifting, the chain needs to be moved from the current sprocket to another, and the chain is in a tilted transition state, which makes it very easy for the chain to slip or jam, causing inconvenience to the rider and even posing a safety hazard. Second, shifting requires the rider to continuously squeeze the shifter until the chain is fully engaged with the target sprocket, making the shifting process laborious and heavy. Third, the existing derailleur has a complex structure, including multiple components such as shift forks, guide wheels, tensioners, and return springs, which are not only heavy and space-consuming, but also have high manufacturing costs and are difficult to assemble and adjust. Fourth, the derailleur requires regular maintenance and adjustment during use, and the shifting accuracy decreases after the chain wears down, further affecting the reliability of the shifting and the riding experience. To address the above problems, there is an urgent need in this field for a bicycle derailleur that can achieve gear shifting without moving the chain, has a simple and compact structure, is easy and effortless to operate, and is stable and reliable in operation. Summary of the Invention

[0003] The purpose of this invention is to provide a frictional rotational lock-up disengagement transmission to solve the problems mentioned in the background art.

[0004] To achieve the above objectives, the present invention provides the following technical solution: a friction-rotational lock-up disengagement transmission, comprising a speed controller mounted on the handlebars and a shifter on the vehicle body, wherein the speed controller and the shifter are connected via a shift cable, and further comprising a transmission, wherein the transmission comprises a friction shifter, a first chainring, a second chainring, a third chainring, and a crank arranged in sequence. The crank passes through the third chainring and the second chainring sequentially via a shaft and is fixedly connected to the first chainring at its end; that is, one end of the shaft is fixedly connected to the crank, and the other end passes through the center holes of the third and second chainrings and is fixedly connected to the first chainring, allowing the crank to directly drive the first chainring to rotate via the shaft. The second and third chainrings are connected to the crank via bearings; specifically, the second and third chainrings are respectively sleeved on the outside of the shaft via bearings, allowing the second and third chainrings to rotate freely relative to the crank, meaning that the second and third chainrings will not be forced to rotate when the crank rotates. The first, second, and third chainrings are each individually connected to a chain, and each chainring drives a corresponding flywheel on the rear wheel through its own chain, achieving different gear ratios. The crank is equipped with a linkage mechanism, and the friction shifter controls the second and third chainrings through this mechanism. The friction shifter is in contact with the gearshift plates, which brake the friction shifter through friction, thereby triggering a gear shift.

[0005] The friction shift disc includes a first turntable and a second turntable, which are rotatably connected, meaning that the first turntable and the second turntable are coaxially arranged and can rotate relative to each other at a certain angle.

[0006] The first turntable is provided with a guide groove, which is divided into a first stop area and a second stop area. The rear of the first stop area is connected to the front of the second stop area, forming a continuous guide path. V-shaped limiting blocks are respectively provided in the first and second stop areas of the guide groove, with each V-shaped limiting block corresponding to one of the two stops. The V-shaped limiting blocks are connected to the groove by pins and can rotate within the groove. A return spring is connected to the bottom of the pin to limit the rotation of the V-shaped limiting block. When the V-shaped limiting block is pushed and rotated through a certain angle, the return spring can restore it to its initial position, thereby achieving unidirectional limiting of the support rod. The first turntable is provided with two stops.

[0007] The second turntable is connected to a fixed circular plate at its center by several connecting ribs. These ribs are radially distributed, connecting the outer ring of the second turntable to the central fixed circular plate. One of these connecting ribs has a rotating rod, one end of which is rotatably connected to the connecting rib, and the other end has a support rod at its bottom. The support rod extends into a guide groove and can slide within the groove. The end of the rotating rod is connected to the outer side of the fixed circular plate by a spring, ensuring that the rotating rod always moves towards the center of the second turntable. One end of the spring is connected to the end of the rotating rod, and the other end is connected to the outer side of the fixed circular plate. Under the spring's tension, the rotating rod always tends to rotate towards the center, thus ensuring that the support rod moves closely against the side wall of the guide groove. The outer side of the fixed circular plate has a first clearance groove and a second clearance groove. The first clearance groove provides movement space for the components of the linkage mechanism, and the second clearance groove has a push rod. The push rod is rotatably connected to the outer side of the fixed circular plate, and the end of the push rod is connected to the inner side of the second turntable by a spring. This spring keeps the push rod extended when no external force is applied. Any one of the connecting ribs is located between two stops, with the two stops located on either side of the connecting rib, to limit the relative rotation range between the first and second turntables. The first turntable is connected to a connecting rib by a spring, which provides a restoring force so that the first and second turntables can return to their original positions after relative rotation.

[0008] As a further improvement of the present invention, a pressure transformer is connected to the first chain disc via a movable shaft, and the pressure transformer can swing around the movable shaft on the surface of the first chain disc. The pressure transformer is provided with a pressure rod, which can move with the rotation of the pressure transformer. A third clearance groove is provided at the center of the first chain disc, and the third clearance groove corresponds to the first clearance groove in position; that is, the third clearance groove and the first clearance groove are located at the same angle in axial projection, forming a connected clearance channel. The pressure rod extends to the third clearance groove, moves along the third clearance groove, and acts on the linkage mechanism.

[0009] As a further improvement of the present invention, the linkage mechanism includes a crank arm, a rotating shaft, a first control key, and a second control key. The crank arm and the rotating shaft are fixedly connected, with the crank arm forming a single rotating unit with the rotating shaft as the main body of the crank. The second control key is connected to a groove at the end of the crank arm via a fixed cover plate, and is constrained in the groove and can slide in a certain direction. A first through hole and a mounting hole are provided at the bottom of the rotating shaft. One end of the first control key is connected to the mounting hole at the bottom of the rotating shaft via a spring, which keeps the first control key tending to extend outward. The other end of the first control key is pressed against a pressure rod, meaning the pressure rod can push the first control key to slide along the mounting hole. The second control key contacts a push rod.

[0010] As a further improvement of the present invention, the first through hole communicates with the groove at the end of the crank arm. One end of the bottom of the second control key has an inclined surface, and the other end is threadedly connected to an adjusting rod. A spring is provided on the top of the second control key; one end of the spring abuts against the inner side of the fixed cover plate, and the other end abuts against the top surface of the second control key, so that the second control key always has a downward tendency to move. The inclined surface at the bottom of the second control key extends out of the groove at the end of the crank arm, and this inclined surface is used to engage with the helical teeth on the third chainring ring shaft. The adjusting rod passes through the first through hole and through the rotating shaft; the adjusting rod contacts the push rod, and the push rod can push the adjusting rod and the second control key to slide.

[0011] As a further improvement of the present invention, the first control key includes a crimping part and a plug rod. The top surface of the crimping part has a crimping groove for engaging with the end of the crimping rod, so that the crimping rod can be accurately pressed into the crimping groove and push the first control key. One side of the bottom surface of the crimping part is connected to the plug rod, and the other side has an inclined surface. The plug rod is inserted into the mounting hole, and the inclined surface is used to engage with the helical teeth on the second chain ring shaft.

[0012] As a further improvement of the present invention, the second and third chain discs are provided with a coaxial annular shaft in the middle, and the end face of the annular shaft is provided with helical teeth, that is, the helical teeth are evenly distributed along the circumferential direction of the end face of the annular shaft. The first and second control keys are connected to the helical teeth through their inclined surfaces. When the inclined surface of the control key engages with the groove of the helical tooth, the control key is engaged with the corresponding chain disc, and the power of the crank is transmitted to the corresponding chain disc through the control key.

[0013] As a further improvement of the present invention, a protective cover is provided on the outside of the rotating shaft. The protective cover is fitted over the outside of the rotating shaft and covers all components of the linkage mechanism, so as to protect against dust and foreign objects from entering.

[0014] The technical effects and advantages provided by the present invention in the above technical solution are as follows: This invention, through a clever combination of a friction shifter, a first chainring, a second chainring, a third chainring, and a crank, enables gear shifting without moving the chain, fundamentally avoiding the chain slippage and jamming problems of traditional derailleurs. The friction shifter employs a mechanical stepping structure with the first and second chainrings rotating relative to each other, coupled with a V-shaped limit block and a rotating rod support within the guide groove, ensuring accurate and precise gear shifting with a clear and distinct feel. The linkage mechanism on the crank engages or disengages with the helical teeth on the chainring's annular shaft via a control key, enabling power transfer between different chainrings. Each chainring is independently connected to the chain, and the various transmission systems do not interfere with each other. The overall derailleur structure is simple and compact, with few parts, low manufacturing cost, and easy assembly, making it suitable for upgrading and modifying the gears of various bicycles. Attached Figure Description

[0015] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments recorded in this invention. For those skilled in the art, other drawings can be obtained based on these drawings.

[0016] Figure 1 This is a schematic diagram of the overall structure of the present invention; Figure 2 This is a schematic diagram of the friction shift disc structure of the present invention; Figure 3 This is a schematic diagram of the first turntable structure of the present invention; Figure 4 This is a schematic diagram of the second turntable structure of the present invention; Figure 5 This is a schematic diagram of the first chain disk structure of the present invention; Figure 6 This is a schematic diagram of the crank linkage mechanism of the present invention; Figure 7 This is an exploded view of the crank linkage mechanism of the present invention; Figure 8 This is a schematic diagram of the bottom structure of the crank linkage mechanism of the present invention; Figure 9 This is a schematic diagram of the second control key structure of the present invention; Figure 10 This is a schematic diagram of the first control key structure of the present invention; Figure 11 This is a schematic diagram of an embodiment of the present invention; Figure 12 This is a schematic diagram of the second chain disk structure of the present invention; Figure 13 This is a schematic diagram of the third chain disk structure of the present invention; Figure 14 This is a schematic diagram of the rear flywheel structure of the present invention.

[0017] Explanation of reference numerals in the attached figures: 1. First chainring; 2. Second chainring; 3. Third chainring; 4. Friction shifter; 5. Crank; 6. Shaft; 7. Protective cover; 101. Pressure shifter; 102. Pressure rod; 103. Third clearance groove; 401. First turntable; 402. Second turntable; 501. First control key; 502. Second control key; 503. Mounting hole; 504. Fixed cover plate; 505. First through hole; 506. Adjusting rod; 507. Crank arm; 4011. Guide groove; 4012. V-shaped limit block; 4013. Stop block; 4021. Rotating rod; 4022. Top rod; 4023. Fixed circular plate; 4024. First clearance groove; 4025. Connecting rib; 4026. Second clearance groove; 5011. Pressing part; 5012. Insert rod; 5013. Pressure groove. Detailed Implementation

[0018] To enable those skilled in the art to better understand the technical solution of the present invention, the present invention will be further described in detail below with reference to the accompanying drawings.

[0019] like Figures 1 to 14 As shown, the present invention provides a friction-rotational locking and disengaging derailleur, which is generally composed of a friction shifter 4, a first chainring 1, a second chainring 2, a third chainring 3, and a crank 5 arranged coaxially in sequence. This derailleur is installed at the bottom bracket of a bicycle and works in conjunction with a gear selector on the handlebars and shifters on the frame. The gear selector and shifters are connected by a shift cable, and the rider can control the contact and disengagement between the shifters and the friction shifter 4 by twisting the gear selector.

[0020] One end of the crank 5 is connected to a shaft 6. The shaft 6 passes through the third chainring 3 and the second chainring 2 axially and is fixedly connected to the first chainring 1 at its end. Specifically, one end of the shaft 6 is fixedly connected to the crank arm 507, and the other end of the shaft 6 passes through the center holes of the third chainring 3 and the second chainring 2 and is fixedly connected to the first chainring 1 by screws. This allows the crank 5 to directly drive the first chainring 1 to rotate synchronously via the shaft 6 when it rotates. The first chainring 1 is located at the outermost end of the shaft 6, away from the crank 5. The second chainring 2 and the third chainring 3 are both sleeved on the periphery of the shaft 6 by bearings. That is, rolling bearings are installed between the second chainring 2 and the third chainring 3 and the shaft 6, allowing the second chainring 2 and the third chainring 3 to rotate freely relative to the shaft 6. When the crank 5 rotates, the second chainring 2 and the third chainring 3 are not directly driven by the shaft 6. The friction shifter 4 is located on the outside of the first chainring 1, that is, on the side of the first chainring 1 away from the crank 5. The friction shifter 4 is positioned opposite to the shifter plate, which is fixed on the frame. When the shifter plate contacts the friction shifter 4, friction is generated, which is used to trigger the shifting action.

[0021] The first chainring 1, the second chainring 2, and the third chainring 3 are each individually connected to a chain. Specifically, the first chainring 1 drives the first flywheel on the rear wheel via the first chain, the second chainring 2 drives the second flywheel on the rear wheel via the second chain, and the third chainring 3 drives the third flywheel on the rear wheel via the third chain. The three flywheels have different numbers of teeth, thus achieving three different transmission ratios. Because each chainring is independent, there is no chain movement between different chainrings, completely eliminating the risk of chain derailment.

[0022] The friction shift disc 4 is the core component for shift control, and its specific structure is as follows: The friction shift disc 4 includes a first turntable 401 and a second turntable 402. The first turntable 401 and the second turntable 402 are coaxially arranged and are slidably connected to achieve rotational connection. The friction shift disc 4 is located outside the first chainring 1. The outer edge surface of the first turntable 401 is a friction surface that contacts and cooperates with the shift plate. When the shift plate presses against the outer edge of the first turntable 401, the rotation of the first turntable 401 is restricted.

[0023] A guide groove 4011 is formed on the surface of the first turntable 401 facing the second turntable 402. The guide groove 4011 is an annular groove, divided into a first section and a second section. The rear of the first section is connected to the front of the second section, forming a closed continuous guide path. A V-shaped limiting block 4012 is respectively provided in the first section and the second section. The two V-shaped limiting blocks 4012 are each connected to the bottom of the guide groove 4011 by a pin. The V-shaped limiting block 4012 has a V-shaped profile, with one side being a smoothly transitioned slope and the other side being a steep limiting surface. The V-shaped limiting block 4012 can rotate at a small angle around the pin in the groove. A return spring is connected to the bottom of the pin. One end of the return spring is fixed to the pin, and the other end is fixed to the bottom of the guide groove 4011. The elastic force of the return spring keeps the V-shaped limiting block 4012 in its initial angle position when no external force is applied. The function of the V-shaped limiting block 4012 is as follows: when the support rod slides along one direction of the guide groove 4011, the support rod can push the inclined surface of the V-shaped limiting block 4012 to rotate and make way, allowing the support rod to pass smoothly; when the support rod slides in the opposite direction, the support rod will abut against the limiting surface of the V-shaped limiting block 4012 and be blocked by the V-shaped limiting block 4012, thereby causing the first turntable 401 and the second turntable 402 to rotate relative to each other. The first turntable 401 is also provided with two stops 4013, which are fixed to the surface of the first turntable 401 and distributed circumferentially to limit the rotation range of the connecting rib 4025 on the second turntable 402.

[0024] The second turntable 402 is connected to a fixed circular plate 4023 at its center via several connecting ribs 4025. The second turntable 402 has a ring structure, with the fixed circular plate 4023 located at the center of the second turntable 402. The connecting ribs 4025 are evenly distributed radially, connecting the outer ring of the second turntable 402 to the fixed circular plate 4023 as a whole, forming a hollow structure between adjacent connecting ribs 4025. A rotating rod 4021 is provided on one of the connecting ribs 4025. One end of the rotating rod 4021 is rotatably connected to the connecting rib 4025 via a pin, and the other end of the rotating rod 4021 is a free end. A support rod is fixedly provided at the bottom of the free end, extending downward perpendicularly to the surface of the rotating rod 4021. The support rod extends into the guide groove 4011 of the first turntable 401, and the end of the support rod can slide freely along the trajectory of the groove within the guide groove 4011. The free end of the rotating rod 4021 is connected to the outer side of the fixed circular plate 4023 by a spring. One end of the spring is fixed to the end of the rotating rod 4021, and the other end is fixed to the outer circumferential surface of the fixed circular plate 4023. This makes the rotating rod 4021 always tend to rotate towards the center of the second turntable 402, so that the support rod always travels close to one side wall of the guide groove 4011 when it slides in the guide groove 4011.

[0025] A first clearance groove 4024 and a second clearance groove 4026 are provided on the outer side of the fixed circular plate 4023. Both the first clearance groove 4024 and the second clearance groove 4026 are notches formed by indentation from the outer edge of the fixed circular plate 4023, which are used to provide movement space for the components of the linkage mechanism. A push rod 4022 is provided at the second clearance groove 4026. One end of the push rod 4022 is rotatably connected to the outer edge of the fixed circular plate 4023 by a pin, and the other end of the push rod 4022 is a free end that extends outward along the second clearance groove 4026. The free end of the push rod 4022 is connected to the inner wall of the second turntable 402 by a spring. The elastic force of the spring keeps the push rod 4022 in an outwardly extended state when there is no external force. In the assembled state, any one of the connecting ribs 4025 is located between the two stops 4013, that is, the two stops 4013 are located on both sides of the connecting rib 4025. When the first turntable 401 and the second turntable 402 rotate relative to each other to a certain angle, the stops 4013 will contact the connecting rib 4025, thereby limiting the extreme position of relative rotation. A return spring is also connected between the first turntable 401 and one of the connecting ribs 4025. One end of the return spring is fixed to the surface of the first turntable 401, and the other end is fixed to the connecting rib 4025. It is used to provide a restoring force after the first turntable 401 and the second turntable 402 rotate relative to each other, so that the two return to their initial relative positions.

[0026] A pressure shifter 101 is provided on the first sprocket 1. The pressure shifter 101 is connected to one side surface of the first sprocket 1 via a movable shaft, and the pressure shifter 101 can swing around the surface of the first sprocket 1 around the movable shaft. A pressure rod 102 is fixedly provided on the pressure shifter 101, and the pressure rod 102 extends from the end of the pressure shifter 101 toward the center of the first sprocket 1. When the pressure shifter 101 rotates around the movable shaft, the pressure rod 102 moves with the swing of the pressure shifter 101. A third clearance groove 103 is provided at the center of the first sprocket 1. The third clearance groove 103 is a through groove extending radially along the first sprocket 1. The third clearance groove 103 and the first clearance groove 4024 on the friction shifter 4 are located at the same angular position in axial projection, that is, the third clearance groove 103 and the first clearance groove 4024 are aligned with each other to form a through clearance channel. The end of the pressure rod 102 extends to the third clearance groove 103 for contact and engagement with the first control key 501 of the linkage mechanism.

[0027] The linkage mechanism on crank 5 specifically includes crank arm 507, shaft 6, first control key 501, and second control key 502. Crank arm 507 is the main body of crank 5; one end is used to mount the foot pedal, and the other end is fixedly connected to shaft 6. Crank arm 507 and shaft 6 can be fixed by integral molding or key connection to ensure synchronous rotation. A groove is formed at the end of crank arm 507 connected to shaft 6, recessed inwards along the end face of crank arm 507. Second control key 502 is disposed within this groove and fixed by a fixing cover plate 504. The fixing cover plate 504 is fixed to the end face of crank arm 507 with screws, constraining the second control key 502 within the groove and preventing it from dislodging. The second control key 502 can slide within the groove.

[0028] The bottom of the rotating shaft 6 has a first through hole 505 and a mounting hole 503. The first through hole 505 penetrates the side wall of the rotating shaft 6 radially and communicates with the groove at the end of the crank arm 507. The mounting hole 503 is located on the end face of the rotating shaft 6 along the axial direction. The mounting hole 503 is a blind hole that extends inward from the end face of the rotating shaft 6 to a certain depth. A first control key 501 is disposed in the mounting hole 503. One end of the first control key 501 is connected to the bottom of the mounting hole 503 by a spring. One end of the spring is fixed to the bottom of the mounting hole 503, and the other end abuts against the end of the first control key 501, so that the first control key 501 always tends to protrude outward from the mounting hole 503. The other end of the first control key 501 protrudes from the mounting hole 503 and is press-fitted with the end of the pressure rod 102.

[0029] The specific structure of the second control key 502 is as follows: The second control key 502 is a long strip-shaped block with an inclined surface at one end. This inclined surface extends downwards from the bottom surface of the second control key 502, extending out of the opening at the bottom of the groove at the end of the crank arm 507, for engaging with the helical teeth on the end face of the annular shaft 16 of the third chainring 3. The other end of the second control key 502 is threadedly connected to an adjusting rod 506. The adjusting rod 506 is a slender rod, with one end threaded to the second control key 502 and the other end passing through the first through hole 505 through the rotating shaft 6 and extending to the outside of the rotating shaft 6. The extended end of the adjusting rod 506 contacts the push rod 4022 on the friction shift disc 4. The push rod 4022 pushes the adjusting rod 506 to move along the first through hole 505, thereby causing the second control key 502 to slide within the groove. A spring is provided on the top of the second control key 502. The spring is located between the second control key 502 and the fixed cover plate 504. One end of the spring abuts against the top surface of the second control key 502, and the other end abuts against the inner side of the fixed cover plate 504. The elastic force of the spring makes the second control key 502 always have a downward tendency, ensuring that the inclined surface at the bottom of the second control key 502 can be engaged or ready to be engaged with the inclined teeth of the third chain disk 3 when there is no other external force.

[0030] The first control key 501 includes a crimping part 5011 and a plug rod 5012. The crimping part 5011 is a block structure with a crimping groove 5013 on its top surface. The crimping groove 5013 is an arc-shaped or V-shaped groove that is recessed downward from the top surface of the crimping part 5011. The position of the crimping groove 5013 corresponds to the end of the pressure rod 102, and the end of the pressure rod 102 can be embedded in the crimping groove 5013. The plug rod 5012 is connected to one side of the bottom surface of the crimping part 5011. The plug rod 5012 is a cylindrical rod that is inserted into the mounting hole 503 of the rotating shaft 6 and can slide along the mounting hole 503. The other side of the bottom surface of the crimping part 5011 has an inclined surface that extends downward from the bottom surface of the crimping part 5011 and is used to engage with the helical teeth on the end face of the annular shaft of the second chain disc 2.

[0031] Both the second chainring 2 and the third chainring 3 have coaxial annular shafts in their middle sections. The annular shaft of the second chainring 2 is located on the surface of the second chainring 2 away from the crank 5, and the annular shaft of the third chainring 3 is located on the surface of the third chainring 3 facing the crank 5. Each annular shaft has several evenly distributed helical teeth on its end face, arranged circumferentially along the end face of the annular shaft. The inclination direction of the helical teeth allows the control key to smoothly engage with the tooth grooves when the crank 5 rotates forward and slide out of the tooth grooves when rotating in reverse. The helical teeth on the annular shaft of the second chainring 2 correspond to the inclined surface at the bottom of the first control key 501, allowing the inclined surface of the first control key 501 to engage or disengage from the helical tooth grooves of the second chainring 2. Similarly, the helical teeth on the annular shaft of the third chainring 3 correspond to the inclined surface at the bottom of the second control key 502, allowing the inclined surface of the second control key 502 to engage or disengage from the helical tooth grooves of the third chainring 3. When the inclined surface of the control key engages with the helical tooth groove of the corresponding annular shaft, the power of the crank 5 is transmitted to the chain drive through the control key, driving the chain drive to rotate; when the inclined surface of the control key disengages from the helical tooth groove, the power connection between the chain drive and the crank 5 is disconnected, and the chain drive is in an idle state.

[0032] A protective cover 7 is also provided on the outside of the rotating shaft 6. The protective cover 7 is a cylindrical shell structure that is fitted over the outside of the rotating shaft 6, covering the first control key 501, the second control key 502, the spring, and other components of the linkage mechanism inside. One end of the protective cover 7 is fixed to the crank arm 507, and the other end extends to the vicinity of the third chain plate 3, providing protection against dust, water, and foreign objects, while also preventing external debris from getting entangled or damaging the linkage mechanism.

[0033] Regarding the dimensions and material selection of the aforementioned components, the first chainring 1, the second chainring 2, the third chainring 3, and the friction shifter 4 are all made of high-strength aluminum alloy or stainless steel. Sealed rolling bearings are used, and the springs are made of piano wire or stainless steel spring wire to ensure reliable and fatigue-resistant operation for long-term use. The bearing connection method between each chainring and the crank 5 ensures that the second chainring 2 and the third chainring 3 can rotate freely when uncontrolled, reducing unnecessary energy loss.

[0034] The working process and principle of this transmission are as follows: In the initial state, i.e., in low gear, crank 5 drives the first chainring 1 to rotate via shaft 6. The first chainring 1 drives the rear wheel through its chain, while the second chainring 2 and the third chainring 3 are stationary. Specifically, the inclined surface at the bottom of the first control key 501 does not engage with the helical teeth of the annular shaft of the second chainring 2, nor does the inclined surface at the bottom of the second control key 502 engage with the helical teeth of the annular shaft of the third chainring 3. Therefore, the second chainring 2 and the third chainring 3 do not rotate with crank 5. The shift paddles and the friction shift disc 4 remain separated, with a gap of approximately 10mm between them, ensuring no frictional resistance during normal riding.

[0035] When the rider needs to switch to a medium gear, they twist the gear selector on the handlebars, which pulls the shifter via the shift cable, causing the shifter to contact the outer edge of the first disc 401 of the friction shifter 4 and generate friction. This friction restricts the rotation of the first disc 401, while the second disc 402, connected to the crank 5 via a linkage mechanism, continues to rotate with the crank 5, resulting in relative rotation between the first disc 401 and the second disc 402. During this relative rotation, the support rod at the bottom of the lever 4021 on the second disc 402 slides along the guide groove 4011 on the first disc 401. The support rod moves from the front to the rear of the first gear zone in the guide groove 4011. When it passes the V-shaped limit block 4012 in the first gear zone, the support rod pushes the inclined surface of the V-shaped limit block 4012, causing the V-shaped limit block 4012 to rotate and move out of position. After the support rod passes, the V-shaped limit block 4012 returns to its original position under the action of the return spring. When the support rod reaches the end of the guide groove 4011, it is blocked by the limiting surface of the V-shaped limiting block 4012. At this time, the first turntable 401 and the second turntable 402 rotate relative to each other to the first angle position. At this angle position, a stop block 4013 on the first turntable 401 presses on the pressure transformer 101 on the first chain disc 1, pushing the pressure transformer 101 to rotate around the movable shaft. The pressure rod 102 on the pressure transformer 101 moves accordingly, and the end of the pressure rod 102 presses into the pressure groove 5013 on the top surface of the first control key 501. Overcoming the elastic force of the spring in the mounting hole 503, the first control key 501 is pushed into the mounting hole 503. The inclined surface at the bottom of the first control key 501 moves accordingly and is engaged in the helical tooth groove of the annular shaft of the second chain disc 2. At this time, the rotation of crank 5 is transmitted to the second chainring 2 through shaft 6 and the first control key 501. The second chainring 2 begins to rotate synchronously with crank 5. The second chainring 2 drives the corresponding freewheel on the rear wheel through its chain, and the bicycle travels at a medium speed. During this process, the third chainring 3 is still in an idle state.

[0036] When the rider needs to switch to a higher gear, they twist the gear selector on the handlebars again, and the shift plates once again come into contact with and rub against the outer edge of the first disc 401 of the friction shifter 4. Since the rear of the first gear zone of the guide groove 4011 is connected to the front of the second gear zone, the second disc 402 continues to rotate in the same direction relative to the first disc 401. The support rod enters the second gear zone from the first gear zone and moves to the rear of the second gear zone. After passing the V-shaped limit block 4012 in the second gear zone, it is blocked by the V-shaped limit block 4012, and the first disc 401 and the second disc 402 rotate relative to each other to the second angle position. At this angle position, the push rod 4022 on the first disc 401 disengages from the adjusting rod 506 of the second control key 502. Under the action of the spring, the inclined surface of the second control key 502 extends out of the groove of the crank arm 507 and engages with the helical tooth groove on the annular shaft of the third chainring 3, and the third chainring 3 is connected to the crank 5. It should be noted that the control method here is similar to that of the medium speed gear, that is, high speed transmission is achieved by engaging the second control key 502 with the helical teeth of the third chain wheel 3.

[0037] When the rider needs to shift from a high gear back to a low gear, they turn the gear selector on the handlebars again. The shifter plate contacts and rubs against the outer edge of the first disc 401 of the friction shifter 4. The second disc 402 continues to rotate relative to the first disc 401. The support rod continues to move along the guide groove 4011 and, after passing the V-shaped limit block 4012, returns to the starting position of the guide groove 4011. At this point, the relative rotation angle between the first disc 401 and the second disc 402 returns to zero, the control buttons disengage smoothly from the helical gears, and the bicycle returns to the low gear position.

[0038] Throughout the shifting process, each chainring is connected to its own chain, eliminating any chain movement between different chainrings and preventing chain slippage or jamming. The friction shifter 4 employs a 360-degree circular rotation structure, ensuring smooth shifting regardless of the crank 5's rotation angle. Because the entire shifting process is achieved through a mechanical structure without any electronic components, manufacturing costs are low, service life is long, and maintenance is simple. The inclined design of the helical teeth ensures stable engagement of the control keys during crank forward rotation and smooth disengagement when crank 5 stops or reverses, guaranteeing reliable and smooth shifting.

[0039] Washers are provided between each chainring and between the friction shifter 4 and the adjacent chainring. The washers are made of wear-resistant plastic or metal materials to reduce friction and wear between rotating parts and ensure the flexibility and stability of the relative rotation of each part.

[0040] The foregoing has only described certain exemplary embodiments of the present invention by way of illustration. Undoubtedly, those skilled in the art can modify the described embodiments in various ways without departing from the spirit and scope of the present invention. Therefore, the foregoing drawings and descriptions are illustrative in nature and should not be construed as limiting the scope of protection of the claims of the present invention.

Claims

1. A friction-rotational lock-up disengagement transmission, comprising a speed controller mounted on the handlebars and a gearshift plate mounted on the vehicle body, wherein the speed controller and the gearshift plate are connected via a gearshift cable, characterized in that: The transmission includes a friction shift plate (4), a first chainring (1), a second chainring (2), a third chainring (3), and a crank (5) arranged in sequence. The crank (5) passes through the third chainring (3) and the second chainring (2) in sequence via a shaft (6) and is fixedly connected to the first chainring (1) at its end. The second chainring (2), the third chainring (3), and the crank (5) are connected to each other via bearings. The first chainring (1), the second chainring (2), and the third chainring (3) are each individually connected to a chain. The crank (5) is provided with a linkage mechanism. The friction shift plate (4) controls the second chainring (2) and the third chainring (3) through the linkage mechanism. The friction shift plate (4) is in contact with the gear shift plates. The friction shift disc (4) includes a first turntable (401) and a second turntable (402), which are rotatably connected. The first turntable (401) is provided with a guide groove (4011), which is divided into a first gear area and a second gear area. The rear part of the first gear area is connected to the front part of the second gear area. V-shaped limit blocks (4012) are respectively provided in the first gear area and the second gear area of ​​the guide groove (4011). The V-shaped limit blocks (4012) are connected to the groove by pins. The V-shaped limit blocks (4012) can rotate in the groove. A return spring is connected to the bottom of the pin to limit the rotation of the V-shaped limit blocks (4012). The first turntable (401) is provided with two stops (4013). The second turntable (402) is connected to a fixed circular plate (4023) at its center via several connecting ribs (4025). One of the connecting ribs (4025) is provided with a rotating rod (4021). One end of the rotating rod (4021) is rotatably connected to the connecting rib (4025), and the bottom of the other end is provided with a support rod. The support rod extends into the guide groove (4011) and can slide in the groove. The end of the rotating rod (4021) is connected to the outside of the fixed circular plate (4023) by a spring so that the rotating rod (4021) always approaches the center of the second turntable (402). In the direction, the outer side of the fixed circular plate (4023) is provided with a first clearance groove (4024) and a second clearance groove (4026). A top rod (4022) is provided at the second clearance groove (4026). The top rod (4022) is rotatably connected to the outer side of the fixed circular plate (4023). The end of the top rod (4022) is connected to the inner side of the second turntable (402) by a spring. Any one of the connecting ribs (4025) is located between two stops (4013). The first turntable (401) is connected to a connecting rib (4025) by a spring.

2. The frictional rotational lock-up disengagement transmission according to claim 1, characterized in that: A pressure transformer (101) is connected to the first chain disc (1) via a movable shaft. The pressure transformer (101) is provided with a pressure rod (102). The pressure rod (102) can move with the rotation of the pressure transformer (101). A third clearance groove (103) is provided at the center of the first chain disc (1). The third clearance groove (103) corresponds to the position of the first clearance groove (4024). The pressure rod (102) extends to the third clearance groove (103).

3. The frictional rotational lock-up disengagement transmission according to claim 2, characterized in that: The linkage mechanism includes a crank arm (507), a rotating shaft (6), a first control key (501), and a second control key (502). The crank arm (507) and the rotating shaft (6) are fixedly connected. The second control key (502) is connected to the groove at the end of the crank arm (507) through a fixed cover plate (504). The rotating shaft (6) has a first through hole (505) and a mounting hole (503) at its bottom. One end of the first control key (501) is connected to the mounting hole (503) at the bottom of the rotating shaft (6) through a spring. The other end of the first control key (501) is pressed against the pressure rod (102). The second control key (502) is in contact with the top rod (4022).

4. The frictional rotational lock-up disengagement transmission according to claim 3, characterized in that: The first through hole (505) communicates with the groove at the end of the crank arm (507). The bottom end of the second control key (502) has an inclined surface, and the other end is threaded with an adjusting rod (506). The top of the second control key (502) is provided with a spring. The inclined surface at the bottom of the second control key (502) extends out of the groove at the end of the crank arm (507). The adjusting rod (506) passes through the rotating shaft (6) along the first through hole (505). The adjusting rod (506) contacts the top rod (4022).

5. A frictional rotational lock-up disengagement transmission according to claim 4, characterized in that: The first control key (501) includes a crimping part (5011) and a plug (5012). The top surface of the crimping part (5011) is provided with a crimping groove (5013). The bottom surface of the crimping part (5011) is connected to one side of the plug (5012) and has an inclined surface on the other side. The plug (5012) is inserted into the mounting hole (503).

6. A frictional rotational lock-up disengagement transmission according to claim 5, characterized in that: The second chain disk (2) and the third chain disk (3) are provided with a coaxial ring shaft in the middle. The end face of the ring shaft is provided with helical teeth. The first control key (501) and the second control key (502) are connected to the helical teeth through the inclined surface on them.

7. A frictional rotational lock-up disengagement transmission according to any one of claims 1-6, characterized in that: The outer side of the rotating shaft (6) is provided with a protective cover (7).

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