Flexible drive spindle and gear adjustment device

Abstract

The present application relates to the technical field of transmission, and especially relates to a flexible driving core shaft and gear adjusting device. The flexible driving core shaft comprises a core shaft, a plurality of positioning bosses arranged along the axial direction on the outer wall of the core shaft, and a plurality of gear driving blocks corresponding to the positions and quantity of the positioning bosses, which are sleeved on the core shaft. The adjacent gear driving blocks and the adjacent positioning bosses are evenly distributed along the circumferential direction of the core shaft at an angle. The gear driving block is provided with a gap notch matched with the positioning boss at the edge of the center hole of the gear driving block, which is used for providing a swingable gap for the positioning boss. The outer edge of the gear driving block is provided with a clamping groove. The torsional spring is fixed on one end of the core shaft and clamped on the other end of the gear driving block. The heavy load gear increasing and the light load gear decreasing without stopping the foot can be realized. The power loss caused in the gear shifting process can be avoided, the gear shifting process is more smooth, the riding is more comfortable, and the high and low gear switching is rapid and stable.

Description

Technical Field

[0001] This invention relates to the field of transmission technology, and in particular to a flexible drive spindle and gear adjustment device. Background Technology

[0002] When riding a bicycle, you need to constantly change gears when passing through different road sections to maintain the minimum input and obtain the optimal power for the current situation.

[0003] Existing bicycle derailleurs are broadly classified into two categories: external derailleurs and internal derailleurs. External derailleurs are a common type of shifting system, characterized by their simple structure and light weight. They utilize an open chain mechanism as the transmission system, achieving different chain ratios by shifting the chain onto different sprockets or freewheels. External derailleurs allow for upshifting without stopping the pedals (no footwork required), and downshifting is also possible without stopping on flat roads or gentle slopes. However, on steep inclines, when the derailleur is under heavy load, the pedaling frequency needs to be reduced (lower cadence) to downshift. Traditional external derailleurs suffer from response delays and sluggishness in shifting the chain onto different sprockets. For example, at traffic lights, downshifting from a higher gear requires a certain distance of coasting before the gear is actually engaged, which doesn't meet the rider's desired experience. Therefore, external derailleurs struggle to provide the comfort and ease of use required for riding on complex terrain. Furthermore, the exposed components of external derailleurs are more susceptible to contamination, and they can produce loud noise during shifting and have a tendency for the chain to come off.

[0004] The internal derailleur of a bicycle employs a fully enclosed, tooth-meshing system, offering advantages such as small size, high transmission efficiency, strong load capacity, and dust and water resistance. Its main structure includes a spindle, input mechanism, output mechanism, planetary gear mechanism, and shifting mechanism. The shifting mechanism achieves different gear ratios by altering the transmission paths between different gears. When the rider pedals, force is transmitted to the input mechanism. At this time, the cable mechanism, operated by the rider, rotates the planetary gear mechanism, driving the shifting mechanism to engage the corresponding gears, changing the transmission path and achieving different gear ratios. The output mechanism then transmits the force to the chainring and chain, thus achieving the effect of shifting gears. Compared to external derailleurs, internal derailleurs offer advantages such as smooth, noiseless shifting and instantaneous gear changes.

[0005] Existing internal gearbox designs fall into three categories: 1. Both upshifting and downshifting require stopping the foot; 2. Upshifting does not require stopping the foot, but downshifting does; 3. Downshifting requires not only stopping the foot but also pressing the pedal at a certain angle in the opposite direction (backshifting). These stopping and backshifting actions result in power loss, reduced speed, and increased effort when starting again, impacting riding comfort and experience, and failing to achieve the same gear-shifting effect as external gearboxes.

[0006] Therefore, there is an urgent need in the field to propose a new type of transmission device to overcome the aforementioned limitations of existing transmission technologies. Summary of the Invention

[0007] To address the issues of shift delays, difficulty in handling complex road conditions, need to stop during upshifting or downshifting, resulting in power loss and a poor riding experience in existing gearboxes, this invention provides a flexible drive spindle and gear adjustment device. It features the ability to upshift without stopping under heavy loads and downshift without stopping under light loads, resulting in a superior riding experience.

[0008] A flexible drive spindle includes a spindle and a plurality of positioning bosses arranged axially on the outer wall of the spindle. A gear drive block corresponding to the position and number of the positioning bosses is fitted on the spindle. The gear drive blocks and the positioning bosses are evenly distributed at an angle along the circumference of the spindle. The gear drive block has a clearance notch at the edge of its central hole that cooperates with the positioning boss to provide a swingable gap for the positioning boss. The outer edge of the gear drive block has a groove. It also includes a torsion spring, one end of which is fixed to the spindle and the other end is engaged with the gear drive block.

[0009] Furthermore, the included angle between adjacent positioning bosses along the mandrel circumference is 40-90 degrees.

[0010] Furthermore, the clearance notch is fan-shaped, and the central angle of the fan-shaped arc hole is 360° / N, where N is the number of gears; or, when N is 6 or less, the central angle of the fan-shaped or arc hole is 60°, 72° or 52°.

[0011] Furthermore, the gear shift drive block is mounted on the spindle and is limited to the left and right by the limiting component.

[0012] Furthermore, the outer edge of the gear shift drive block is rounded.

[0013] To achieve the above objectives, the present invention also provides a gear adjustment device, including the aforementioned flexible drive spindle and a bushing. The spindle is axially installed inside the bushing and rotatably connected to the bushing. The bushing is provided with a mounting groove corresponding to the number and position of the gear drive blocks. A pawl that cooperates with a slot is provided in the mounting groove. The middle part of the pawl is rotatably disposed in the mounting groove. An elastic element is connected between the bottom of one end of the pawl and the mounting groove to spring up the end and extend the bottom of the other end of the pawl into the rotation path of the slot.

[0014] Furthermore, the number of pawls is always two or more, and adjacent pawls are set facing each other at a 180-degree angle.

[0015] Furthermore, the pawl is cross-shaped, and a washer is fitted on the bushing. The two sides of the pawl are rotated and installed in the mounting groove through the washer.

[0016] Furthermore, a shifting device that can slide along the axial direction of the spindle is fitted at one end of the spindle; the shifting device is provided with a shifting drive unit, and when the spindle rotates to an angle that cooperates with the shifting device, the shifting device can move linearly along the axial direction of the spindle; on the bushing, a pawl that cooperates with the shifting drive unit is provided at a position corresponding to the shifting drive unit.

[0017] Furthermore, a groove is provided on the side wall of one end of the mandrel along the axial direction, and the shifting device is fitted on the mandrel at the position corresponding to the groove; a limit rod is installed on the outside of the shifting drive part, and the limit rod extends into the groove; the shifting device has a shifting drive part, a shifting ring groove and a rotating groove arranged sequentially on the side wall from the inner end to the outer end, and a drive groove is provided on the side of the shifting drive part; the rotating groove includes two or more arc grooves extending circumferentially along the outside of the shifting sleeve, and the tail of the arc groove is connected to the starting point of the adjacent arc groove through an inclined groove; a sliding rod is vertically provided on the bushing, and the sliding rod extends into the rotating groove; when the mandrel rotates to the angle that matches the shifting device, the rotating groove can make the shifting device move along the groove under the combined action of the limit rod and the sliding rod.

[0018] Furthermore, the central angle of the arc groove is 360°(n-1) / n, where n is the number of gears. When the sliding rod slides into the adjacent arc groove through the inclined groove, the distance that the gear-increasing sleeve moves is equal to the center distance between the two corresponding arc grooves.

[0019] Furthermore, a first planetary gear set and a second planetary gear set are installed at one end of the mandrel; the first planetary gear and the second planetary gear share a planetary carrier; the sun gear 1 in the first planetary gear set is integrally connected to the bushing, and the sun gear 1 is rotatably connected to the mandrel; the gear ring 1 in the first planetary gear set is rotatably connected to the bushing; the sun gear 2 in the second planetary gear set is keyed to the mandrel, and the gear ring 2 in the second planetary gear set is fitted outside the gear ring 1 in the first planetary gear set; the gear ring 2 is driven by a gear adjustment device, and a gear adjustment knob is fixed at the other end of the mandrel, and a gear position mark is provided at the end of the bushing corresponding to the gear adjustment knob.

[0020] Furthermore, a rope groove is provided on the outer side of the gear ring in the second planetary gear set, and the gear adjustment device is a gear adjustment pull rope that is wound around the ring groove.

[0021] Furthermore, the gear shifting device is a control motor, which is connected to the gear ring two for driving the gear ring two to rotate.

[0022] Furthermore, one or more positioning grooves are provided on the inner side of one end of the bushing, and the spindle is provided with corresponding elastic clips that cooperate with the positioning grooves. The elastic clips can enter or disengage from the positioning grooves when the spindle rotates.

[0023] The beneficial effects of this invention are as follows:

[0024] 1. This invention utilizes a clever mechanical matching transmission principle, which has many advantages such as fast shifting response, high transmission efficiency, wide speed ratio, heavy load upshifting, light load downshifting, and arbitrary skipping of gears, thus making up for the shortcomings of traditional external transmissions.

[0025] 2. It enables upshifting under heavy loads and downshifting under light loads without stopping, avoiding power loss during gear changes, resulting in smoother shifting and a more comfortable ride. High and low gear switching is quick and stable under both heavy and light load conditions.

[0026] 3. When the pull cord for shifting gears has been used for a long time, the pull cord may stretch, which will cause inaccurate gear shifting. This solution can be used to quickly restore the gear to the gear corresponding to the length of the pull cord by rotating the spindle of the gear adjustment knob and checking the gear position markings.

[0027] 4. When using a gear-boosting sleeve, the number of gears can be multiplied, resulting in better riding comfort, while maintaining a small size. Attached Figure Description

[0028] Figure 1 This is a schematic diagram of the flexible drive spindle of the present invention;

[0029] Figure 2 for Figure 1 A structural diagram from another perspective;

[0030] Figure 3 for Figure 1 A structural diagram from another perspective;

[0031] Figure 4 Another structural schematic diagram of the flexible drive mandrel of the present invention;

[0032] Figure 5 for Figure 4 A structural diagram from another perspective;

[0033] Figure 6 A schematic diagram of the mandrel and positioning boss;

[0034] Figure 7 This is a schematic diagram of the upgrade device;

[0035] Figure 8 for Figure 7 A structural diagram from another perspective;

[0036] Figure 9 This is a schematic diagram of the gear shift drive block;

[0037] Figure 10 A schematic diagram of the structure of the flexible drive spindle and the pawl in operation;

[0038] Figure 11 A schematic diagram of the assembly structure of the flexible drive spindle and the pawl;

[0039] Figure 12 This is a schematic diagram of the speed regulation device.

[0040] Figure 13 This is a schematic diagram of an internal gear structure of a transmission.

[0041] Figure 14 for Figure 13 Cross-sectional view;

[0042] Figure 15 This is a diagram of the external structure of the transmission;

[0043] Figure 16 A schematic diagram of the positioning groove and the elastic clip;

[0044] Figure 17 for Figure 16 AA section diagram;

[0045] In the diagram: 1. Mandrel; 2. Positioning boss; 3. Gear drive block; 4. Clearance notch; 5. Opening groove; 6. Shim; 7. Slot; 8. Torsion spring; 9. Bushing; 10. Mounting groove; 11. Pawl; 12. Elastic element; 13. Gear shifting device; 14. Gear drive unit; 15. Slide groove; 16. Limiting rod; 17. Gear shifting ring groove; 18. Rotating groove; 20. Arc groove; 21. Inclined groove; 22. Sliding rod; 23. First planetary gear set; 2301. Sun gear one; 2302. Planetary gear one; 2303. Planetary support; 2304. Ring gear one; 24. Second planetary gear set; 2401. Sun gear two; 2402. Planetary gear two; 2403. Ring gear two; 2404. Rope groove; 25. Gear shift knob; 26. Gear position indicator; 27. Positioning groove; 28. Elastic retainer; 29. ​​Limiting element; 30. Shift gear; 31. Input shaft; 32. Output gear shaft; 33. Output gear; 34. Input gear; 35. Chainring; 36. Gearbox housing; 37. Bearing; 38. Pull rope. Detailed Implementation

[0046] The following description, in conjunction with specific embodiments, further illustrates the flexible drive spindle and gear adjustment device of the present invention.

[0047] like Figure 1 , Figure 2 , Figure 3 , Figure 4 , Figure 5 , Figure 6 As shown, a flexible drive spindle includes a spindle 1 and a plurality of positioning bosses 2 arranged axially along the outer wall of the spindle 1. A gear drive block 3 corresponding to the position and number of the positioning bosses 2 is fitted on the spindle 1. The gear drive blocks 3 and the positioning bosses 2 are evenly distributed at an angle along the circumference of the spindle 1. The gear drive block 3 has a clearance notch 4 at the edge of its central hole that cooperates with the positioning bosses 2 to provide a swingable gap for the positioning bosses 2. The outer edge of the gear drive block 3 is arc-shaped and has a groove 7 on the outer edge. It also includes a torsion spring 8, one end of which is fixed on the spindle 1 and the other end is locked on the gear drive block 3.

[0048] The positioning boss 2 is used to cooperate with the gear shift drive block 3 to realize gear shifting under load. In this solution, the gear shift drive block 3 is an arc-shaped structure with a groove 7. The outer surface of the arc-shaped structure can be a circular arc or an elliptical arc, so that one end of the pawl 11 can slide against the outer surface of the gear shift drive block 3 under the action of the elastic element 12. To ensure that the pawl 11 does not jump, a circular arc outer surface is optimal. The groove 7 is an arc-shaped recess on the outer edge of the gear shift drive block 3, so that when one end of the pawl slides into the arc-shaped recess, the other end can be bounced up by the elastic element and engaged with the corresponding gear shifting gear. In other embodiments, the groove 7 can also be other shapes, as long as it can facilitate the pawl 11 to engage with the groove and be easily disengaged.

[0049] The spindle 1 has a socket, and the corresponding gear drive block 3 has an opening slot 5; the two ends of the torsion spring 8 are respectively inserted into the spindle 1 and the opening slot 5 of the gear drive block 3; the opening slot 5 facilitates the installation of the torsion spring 8.

[0050] Since this structure lacks a clutch, the combination of the gear shift drive block 3 and the torsion spring is used to shift gears under load. When the spindle 1 begins to rotate and shift gears, it allows the current engaged gear to remain unchanged while engaging the next gear. Because shifting gears is an acceleration process, after the next gear engages, the previous gear automatically resets under the action of the gear shift drive block 3 and the torsion spring 8.

[0051] Better, such as Figure 9 As shown, the clearance notch 4 is fan-shaped, and the central angle of the arc-shaped fan-shaped hole is 360° / N, where N is the number of gears. This angle is related to the number of gears and can be divided into 360° according to the number of gears. For example, for 9 gears, the central angle of clearance notch 4 is 40°; for 8 gears, it is 45°; for 6 gears, it is 60°; for 5 gears, it is 72°; for 4 gears, it is 90°; and for 7 gears, it is approximately 52°. Alternatively, when there are six gears or less, the central angle of clearance notch 4 can be fixed at one angle (e.g., 60°, 72°, 52°). The arc length of the clearance notch is greater than half the arc length of the slot of the gear drive block 3. That is, when the outer end of the positioning boss 2 rotates by the arc length of the clearance notch, the pawl 11 corresponding to the next gear can slide out from the slot of its corresponding gear drive block 3, that is, the arc-shaped recess.

[0052] Better, such as Figure 6As shown, the included angle between adjacent positioning bosses 2 along the circumference of the spindle 1 is 40-90 degrees. The circumferential angle between adjacent positioning bosses 2 is related to the gear position, so that when the spindle 1 rotates to this angle, the positioning bosses 2 can drive the gear drive block 3, and the pawl 11 at a certain position can slide into the arc-shaped recess of the corresponding gear drive block 3. For example, with six gears, the angle between adjacent positioning bosses 2 along the circumference of the spindle 1 is 60°; with eight gears, the angle is 45°. In this design, the preferred included angles between adjacent positioning bosses 2 are 60°, 72°, and 45°.

[0053] Preferably, the pawl 11 is cross-shaped, and the corresponding mounting groove 10 is also cross-shaped. The mounting groove 10 has groove bottoms on both axial sides, a groove bottom on one radial side for mounting the elastic element, and a hollowed-out side on the other radial side to allow one end of the pawl to rotate downwards and extend into the arc-shaped recess of the gear shift drive block 3. A washer 6 is fitted onto the bushing 9, and both sides of the pawl 11 are rotatably mounted in the mounting groove 10 via the washer 6. The pawl is fixed without the traditional bolt-fixing method, avoiding the risk of bolts falling into the device and helping to improve its service life.

[0054] Better, such as Figure 2 As shown, the gear shift drive block 3 is mounted on the spindle 1 and is limited to the left and right sides by the limiting member 29. In this embodiment, annular grooves are provided on the left and right sides of the gear shift drive block 3 on the spindle 1, and the limiting member 29 is a thin clamp, which is mounted on the spindle 1 and placed in the annular groove.

[0055] The flexible drive spindle in this solution is suitable for gearboxes, and is applicable to gear shifting and gear changing in vehicles such as bicycles, cars, motorcycles, and electric vehicles. It is especially suitable for bicycle gearboxes. The following is a detailed explanation in conjunction with the gear adjustment device and bicycle gearbox.

[0056] like Figure 10 , Figure 11 , Figure 12 As shown, the gear adjustment device includes the aforementioned flexible drive shaft and a bushing 9. The spindle 1 is axially installed inside the bushing 9 and rotatably connected to the bushing 9. The bushing 9 is provided with mounting grooves 10 corresponding to the number and position of the gear drive blocks 3. A pawl 11 that cooperates with the slot 7 is provided in the mounting groove 10. The middle part of the pawl 11 is rotatably set in the mounting groove 10. An elastic element 12 is connected between the bottom of one end of the pawl 11 and the mounting groove 10 to spring up the end and extend the bottom of the other end of the pawl 11 into the rotation path of the slot 7.

[0057] like Figure 10 , Figure 13As shown, several shift gears 30 are fitted on the outside of the bushing 9. The shift gears 30 can rotate on the bushing 9. The shift gears 30 are limited on the bushing 9 by the shims 6 and correspond one-to-one with the position of the pawl 11. The shims 6 are used to separate and limit the left and right movement of each shift gear 30, and also to limit the pawl 11. In this scheme, there is a rotating block on each side of the pawl 11. The shims 6 on both sides rotate the rotating blocks on both sides of the pawl 11 into the mounting groove 10, so that it can rotate in the mounting groove 10. An elastic element 12, such as a spring, is installed below one end of the pawl 11, so that when one end of the pawl 11 enters the arc-shaped recess of the gear drive block 3, the other end of the pawl 11 can be raised. When one end of the pawl 11 slides out of the arc-shaped recess of the gear drive block 3, the other end of the pawl 11 compresses the spring and falls down. The inner ring of the gear shifter 30 is provided with an inner retaining tooth. When the spindle 1 is rotated, a pawl 11 on the spindle 1 springs up at one end under the action of the elastic element 12, thereby locking the inner retaining tooth of the gear shifter 30 corresponding to the pawl 11.

[0058] like Figure 13 , Figure 14 , Figure 15 As shown, the bicycle transmission includes an input shaft 31, an output gear shaft 32 rotatably mounted at one end of the input shaft 31, and an output gear 33 keyed to the output gear shaft 32; an input gear 34 keyed to the end of the input shaft 31 away from the output end, and an output gear 33 keyed to the output gear shaft 32; the input gear 34 and the output gear 33 respectively mesh with the shift gear 30; and a planetary gear set for shifting gears is mounted at the end of the flexible drive spindle.

[0059] When gear shifting is required, the shifting device drives the planetary gear set, which in turn rotates the spindle 1 by a certain angle. During this process, as the spindle 1 rotates, the end of the pawl 11 away from the elastic element 12 slides on the arc-shaped outer surface of the gear shift drive block 3. When it slides into the slot, the end of the pawl 11 with the elastic element 12 can spring up, and the protruding end of the pawl 11 can engage the inner teeth of the corresponding shift gear 30 rotatably mounted on the outside of the bushing 9. Depending on the gear configuration, each shift shift involves two shift gears 30 engaging and transmitting power with the corresponding pawl 11. The two shift gears 30 respectively mesh with the input gear 34 and the output gear 33 to achieve gear engagement.

[0060] The input shaft 31 is connected to the bicycle pedals, and the output shaft is connected to the chainring 35. When the rider pedals, the input shaft 31 drives the input gear 34 to rotate, which in turn drives the shift gear 30. The shift gear 30 not engaged with the ratchet pawl 11 rotates freely, while the shift gear 30 engaged with the ratchet pawl 11 drives the bushing 9 to rotate. The bushing 9 then drives the other shift gear 30 engaged with the ratchet pawl 11 to rotate, and the power is output to the output shaft via the output gear 33. The output shaft then transmits the power to the chainring 35, which in turn transmits the power to the rear wheel via the chain. Different gear ratios can be achieved by adjusting the input gear 34, output gear 33, and shift gear 30.

[0061] Under load, such as when riding on flat roads or gentle slopes, the pedals are under light load, and shifting gears can generally be done directly. However, when climbing hills, a greater force is needed to drive the pedals; this is a heavy load situation, and shifting gears requires reducing the cadence. Existing bicycle derailleurs, such as the one in patent number 202210071876.X, are titled "A Gear Shifting Device." Figure 8 The gear shift spindle 1 shown in the image has an integrated structure of cam and shift spindle 1. Under load, when shifting up a gear, such as from fifth to sixth gear, due to the load, one end of the pawl 11 corresponding to fifth gear is stuck in the arc-shaped recess of the corresponding cam, while the other end of the pawl 11 remains raised under the action of the elastic element 12. The raised end cannot disengage from the shift gear 30 corresponding to fifth gear. At this time, because the cam and spindle 1 are an integrated structure in this patent, the spindle 1 cannot rotate, causing one end of the pawl 11 corresponding to sixth gear to be unable to slide on the corresponding cam and enter the arc-shaped recess of the cam. The other end of the pawl 11 corresponding to sixth gear cannot be raised, thus preventing the pawl 11 corresponding to sixth gear from engaging with the shift gear 30 and preventing sixth gear from being engaged. Therefore, this type of spindle 1 structure requires stopping the pedal when shifting up. Only when the pedal is stopped, and there is no significant force between the pawl 11 corresponding to fifth gear and the arc-shaped recess of the cam, can the load be released, thereby driving the shift spindle 1 to rotate. This causes one end of the pawl 11 corresponding to fifth gear to slide onto the side of the cam on its corresponding arc-shaped recess, causing the other end of the pawl 11 corresponding to fifth gear to press against the elastic element 12 and fall down, thus disengaging from the corresponding gear 30. At the same time, one end of the pawl 11 corresponding to sixth gear slides into the corresponding arc-shaped recess of the cam, causing the other end of the pawl 11 corresponding to sixth gear to engage with the corresponding gear. The same applies to downshifting.

[0062] In this scheme, a six-speed transmission is taken as an example. The angular difference between adjacent gear drive blocks 3 and positioning bosses 2 along the circumference of the spindle 1 is 60°. Under load, although one end of the pawl 11 corresponding to the fifth gear is locked with the arc-shaped recess of the corresponding gear drive block 3, the positioning boss 2 and the gear drive block 3 are separate structures. The gear drive block 3 has a clearance notch 4 on the edge of its own central hole that cooperates with the positioning boss 2, which is used to provide a swingable gap for the positioning boss 2. The spindle 1 can rotate. The gear shifting device can drive the spindle 1 to rotate first through the planetary gear set and drive the positioning boss 2 to rotate at the angle corresponding to the clearance notch 4, such as 60°. Since the torsion spring 8 connects the spindle 1 and the gear drive block 3 corresponding to the sixth gear, the gear drive block 3 also rotates 60°, so that one end of the pawl 11 corresponding to the sixth gear slides into the arc-shaped recess of the gear drive block 3 corresponding to the sixth gear, and the other end of the pawl 11 corresponding to the sixth gear lifts up, thereby locking the shift gear 30 corresponding to the sixth gear and entering the sixth gear state. Meanwhile, since the torsion spring 8 is connected to the spindle 1 and the gear drive block 3, the rotation of the spindle 1 generates torque in the torsion spring 8 connected to the gear drive block 3 corresponding to the fifth gear. The gear drive block 3 corresponding to the fifth gear rotates to give way to half the central angle of the notch 4. The pawl 11 corresponding to the fifth gear is still in the state of being located at the edge of the arc-shaped recess of the gear drive block 3 corresponding to the fifth gear. At the moment the sixth gear is completed, since the sixth gear tooth is larger than the fifth gear, the speed of the shift gear 30 corresponding to the sixth gear is faster than that of the shift gear 30 corresponding to the fifth gear. Under the stress of the torsion spring 8, the shift gear 30 corresponding to the fifth gear can press one end of its corresponding pawl 11 out of the arc-shaped recess of the gear drive block 3 corresponding to the fifth gear and slide on the outer edge of the gear drive block 3. At the same time, due to the action of the torsion spring 8, the gear drive block 3 corresponding to the fifth gear automatically resets, realizing the effect of automatic reset of the previous gear after the next gear is completed, and shifting gears in advance and downshifting in reverse. The foot does not need to stop during the upshifting process, and the load shifting can be realized during riding, greatly improving the riding experience.

[0063] Downshifting under light or heavy load conditions:

[0064] For example, when downshifting from second to first gear, the gear shifting device drives the flexible drive spindle to rotate in the opposite direction via the planetary gear set. At this time, the positioning boss 2 abuts against the edge of the clearance notch on the gear drive block 3. The positioning boss 2 on the flexible drive spindle rotates accordingly, thereby driving the gear drive block 3 to rotate. At this time, one end of the pawl 11 corresponding to first gear slides into the arc-shaped groove in the corresponding gear drive block 3, realizing gear engagement. At the same time, since the speed ratio of second gear is higher than that of first gear, under light load conditions, such as on flat roads, gentle slopes, or downhill, the force on the pawl 11 corresponding to second gear and the arc-shaped recess of the corresponding gear drive block 3 is very light. Under the action of the positioning boss 2, one end of the arc-shaped groove of the gear drive block 3 corresponding to second gear can be pried off using the lever principle, causing that end to disengage from the arc-shaped groove of the corresponding gear drive block 3 and enter the outer surface of the gear drive block 3. This causes the other end of the pawl 3 corresponding to second gear to compress the elastic element, completing the downshifting process. The downshifting process under heavy load is similar. However, because the pawl 11 corresponding to second gear and the arc-shaped recess of the corresponding gear drive block 3 are under great force at this time, it is only necessary to reduce the pedal frequency and reduce the force to continue to complete the downshifting steps. This solves the problem that existing types of internal transmissions require stopping the pedal for both upshifting and downshifting, or upshifting without stopping the pedal, but downshifting requires stopping the pedal or not only stopping the pedal but also pressing the pedal at a certain angle in the opposite direction (reverse pedaling) during downshifting.

[0065] The shifting process of this invention can be completed instantly. Based on the above shifting process, the user can achieve arbitrary gear skipping by continuously operating the shifting device, such as directly from 5th gear, 4th gear, 3rd gear, 2nd gear to 1st gear. Unlike the existing technology where the external derailleur needs to coast for a distance before shifting to 1st gear, this invention solves this problem of the external derailleur and can meet the rider's requirement to obtain the desired riding speed according to the current road conditions.

[0066] Preferably, the number of positioning boss 2, gear shift drive block 3, and pawl 11 are all two or more, thus meeting the requirement of multi-gear switching. The adjacent pawls 11 are arranged at 180 degrees to avoid having to drill a mounting hole on one side of the bushing 9 to install the pawl 11. If the mounting hole is a through hole, it will make the installation of the pawl 11 inconvenient; if the hole is separated, the corresponding bushing 9 will be larger to accommodate it. This solution arranges the pawls at 180 degrees to facilitate drilling holes on both sides of the bushing 9, making the installation of the pawl 11 easier, without affecting the original function of the pawl 11.

[0067] Compared to existing technologies, this solution eliminates the need for a shift fork to switch between different gears and engage with the pawl 11, resulting in smooth and stable gear shifting and a smaller overall size.

[0068] Better, such as Figure 4 , Figure 5 , Figure 7 , Figure 8 As shown, a shifting device 13 that can slide along the axial direction of the spindle 1 is fitted at one end of the spindle 1; the shifting device 13 is provided with a shifting drive part 14, and when the spindle 1 rotates to an angle that cooperates with the shifting device 13, the shifting device 13 can move linearly along the axial direction of the spindle 1; on the bushing 9, a pawl 11 that cooperates with the shifting drive part 14 is provided at a position corresponding to the shifting drive part 14.

[0069] The gear-multiplying device 13 is used to multiply the number of gears within the limited volume of the bushing 9, providing a smoother gear-shifting experience. The gear drive unit 14 has the same function as the gear drive block 3, both of which are used to make the other end of the corresponding pawl 11 lift up and lock the corresponding gear 30 when one end of the pawl 11 slides into the arc-shaped recess on the gear drive unit 14.

[0070] Preferably, a groove 15 is provided on one end sidewall of the spindle 1 along the axial direction, and the shifting device 13 is fitted on the spindle 1 at a position corresponding to the groove 15; a limit rod 16 is installed on the outside of the shifting drive part 14, and the limit rod 16 extends into the groove 15; the shifting device 13 has a shifting drive part 14, a shifting ring groove 17 and a rotating groove 18 arranged sequentially on the sidewall from the inner end to the outer end, and a drive groove is provided on the side of the shifting drive part 14, which acts on the arc-shaped recess on the shifting drive block. The parts are similar; the rotating groove 18 includes two or more arc grooves 20 extending circumferentially along the outer side of the booster sleeve, and the tail of the arc groove 20 is connected to the starting point of the adjacent arc groove 20 through the inclined groove 21; the bushing 9 is provided with a vertical sliding rod 22, which extends into the rotating groove 18; when the spindle 1 rotates to the angle that matches the booster device 13, the rotating groove 18 can make the booster device 13 move along the slide groove 15 under the combined action of the limiting rod 16 and the sliding rod 22.

[0071] Preferably, the central angle of the arc groove 20 is 360°(n-1) / n, where n is the number of gears. When the sliding rod 22 slides into the adjacent arc groove 20 through the inclined groove 21, the distance the shifting sleeve moves is equal to the center distance between the two corresponding arc grooves 20. N is the number of input gears, 360° / N. For example, if the gear shifting device has 6 gears, the central angle of the arc groove 20 is 300°. During the first 300° of the rotation of the spindle 1, the shifting sleeve remains in its original position because the arc grooves 20 are distributed circumferentially along the spindle 1. During the last 60° of the rotation, the sliding rod 22 rotates to the inclined groove 21 and slides from the inclined groove 21 to the adjacent arc groove 20. The shifting device 13 then begins to slide along the sliding groove 15 of the spindle 1. The distance the shifting sleeve moves each time is equal to the center distance between the two corresponding arc grooves 20. For example, the speed adjustment device has 4 gears, the central angle of the arc groove 20 is 270°, the spindle 1 remains stationary for the first 270 degrees during the rotation process, the gear-increasing sleeve remains in its original position, and during the last 90 degrees of the rotation process, the sliding rod 22 rotates to the inclined groove 21 and slides from the inclined groove 21 to the adjacent arc groove 20.

[0072] By setting up the gear-increasing device 13, the number of gears in the gear-shifting adjustment device is A*B, where A is the number of input gears 34 and B equals the number of arc grooves 20 equaling the number of output gears 33, achieving a gear multiplication effect. Generally, three arc grooves 20 are used. More gears result in smoother gear shifting and a more comfortable experience. It also reduces the overall size and eliminates the need for a shift fork.

[0073] Preferably, a first planetary gear set 23 and a second planetary gear set 24 are installed at one end of the spindle 1; the first planetary gear and the second planetary gear share a planetary support 2303; the sun gear 2301 in the first planetary gear set 23 is integrally connected to the bushing 9, and the sun gear 2301 is rotatably connected to the spindle 1; the gear ring 2304 in the first planetary gear set 23 is rotatably connected to the bushing 9; the sun gear 2401 in the second planetary gear set 24 is keyed to the spindle 1, and the gear ring 2403 in the second planetary gear set 24 is fitted outside the gear ring 2304 in the first planetary gear set 23; the gear ring 2403 is connected to a gear shifting device, and a gear shifting button 25 is fixed at the other end of the spindle 1, and a gear position mark 26 is provided at the end of the bushing 9 corresponding to the gear shifting button 25.

[0074] The sun gear 2301 and the bushing 9 in the first planetary gear set 23 are provided with mounting holes at corresponding positions, and the two are connected as one unit by connecting screws.

[0075] External gear ring 2403 is used to drive the rotating spindle for gear shifting, while gear ring 1 2304 remains stationary. During gear shifting, gear ring 2403 is pulled by a rope or driven by a motor. Since two planetary gear sets share a single planetary support 2303, when gear ring 2403 is driven, because sun gear 1 2301 is rotatably connected to spindle 1 and fixedly connected to bushing 9, and planetary support 2303 is stationary, only planetary gear 2402 can drive sun gear 1 2401, rotating it by a certain angle to achieve gear shifting.

[0076] In this embodiment, the gear adjustment knob 25 is equipped with or printed with an indicator arrow, and the gear position mark 26 is the gear position corresponding to the end of the bushing 9;

[0077] like Figure 16 , Figure 17 As shown, one or more positioning grooves 27 are provided inside the bushing 9 at one end near the planetary support 2303. The spindle 1 is provided with corresponding elastic retainers 28 that cooperate with the positioning grooves 27. The elastic retainers 28 can enter or disengage from the positioning grooves 27 when the spindle 1 rotates. The positioning grooves 27 are used for initial positioning of the gear shift of the transmission. There is at least one elastic retainer 28, and preferably two or more.

[0078] Preferably, a rope groove 2404 is provided on the outer side of the gear ring 2403 in the second planetary gear set 24, and the gear shifting device is a gear shifting pull rope 38 wound around the rope groove 2404. The more turns the rope groove 2404 has, the longer the gear shifting pull rope 38 can be wound. In this design, the rope groove 2404 has more than two turns, which is suitable for transmissions with 10 or more gears.

[0079] After the gear shifting device is initially positioned, the pull rope 38 for shifting gears may stretch after prolonged use, which may lead to inaccurate gear shifting. This solution can be achieved by rotating the spindle 1 using the shift knob 25 and following the arrow on the gear position indicator 26 to quickly restore the gear to the position corresponding to the length of the pull rope 38.

[0080] Preferably, the gear shifting device is a control motor, which is connected to the gear ring 2403 for driving the gear ring 2403 to rotate. The control motor can be a stepper motor, used to drive the gear ring 2403 to rotate in the forward and reverse directions, thereby shifting gears.

Claims

1. A flexible drive mandrel, characterized in that, The device includes a spindle (1) and several positioning bosses (2) arranged axially on the outer wall of the spindle (1). The spindle (1) is fitted with gear drive blocks (3) corresponding to the position and number of positioning bosses (2). The gear drive blocks (3) and the positioning bosses (2) are evenly distributed at an angle along the circumference of the spindle (1). The gear drive blocks (3) have a clearance notch (4) at the edge of their own central hole that cooperates with the positioning bosses (2) to provide a swingable gap for the positioning bosses (2). The gear drive blocks (3) are provided with a slot (7). The device also includes a torsion spring (8), one end of which is fixed on the spindle (1) and the other end is locked on the gear drive block (3).

2. The flexible drive mandrel as described in claim 1, characterized in that, The included angle between adjacent positioning bosses (2) along the circumference of the mandrel (1) is 40-90 degrees.

3. The flexible drive mandrel as described in claim 1 or 2, characterized in that, The clearance gap (4) is fan-shaped, with a central angle of 360° / N, where N is the number of gears; or, when N is 6 or 5 or less, the central angle of the fan is 60°, 72° or 52°.

4. A gear adjustment device, characterized in that, The flexible drive spindle as described in any one of claims 1 to 3 is further comprising a bushing (9), wherein the spindle (1) is axially mounted inside the bushing (9) and rotatably connected to the bushing (9); the bushing (9) is provided with mounting grooves (10) corresponding to the number and position of the gear drive blocks (3), and a pawl (11) that cooperates with the slot (7) is provided in the mounting groove (10), wherein the middle part of the pawl (11) is rotatably disposed in the mounting groove (10), and an elastic element (12) is connected between the bottom of one end of the pawl (11) and the mounting groove (10) for springing up the end and extending the bottom of the other end of the pawl (11) into the rotation path of the slot (7).

5. The gear adjustment device as described in claim 4, characterized in that, The pawl (11) is cross-shaped, and a gasket (6) is fitted on the bushing (9). The two sides of the pawl (11) are rotatably installed in the mounting groove (10) through the gasket (6).

6. The gear adjustment device as described in claim 4 or 5, characterized in that, The number of pawls (11) is two or more, and adjacent pawls (11) are set facing each other at 180 degrees.

7. The gear adjustment device as described in claim 4 or 5, characterized in that, A gear-shifting device (13) that can slide along the axial direction of the spindle (1) is fitted at one end of the spindle (1); a gear-shifting device (13) is provided on the gear-shifting device (14), and when the spindle (1) rotates to an angle that cooperates with the gear-shifting device (13), the gear-shifting device (13) can move linearly along the axial direction of the spindle (1); on the bushing (9), a pawl (11) that cooperates with the gear-shifting device (14) is provided at a position corresponding to the gear-shifting device (14).

8. The gear adjustment device as described in claim 6, characterized in that, A groove (15) is provided on the side wall of one end of the spindle (1) along the axial direction. The gear shifting device (13) is fitted on the spindle (1) at the position corresponding to the groove (15). A limit rod (16) is installed on the outside of the gear shifting drive part (14), and the limit rod (16) extends into the groove (15). The gear shifting device (13) has a gear shifting drive part (14), a gear shifting ring groove (17), and a rotating groove (18) arranged sequentially on the side wall from the inner end to the outer end. A drive groove (19) is provided on the side of the gear shifting drive part (14). The rotating groove (18) It includes two or more circular arc grooves (20) extending circumferentially along the outer side of the booster sleeve. The tail of the circular arc groove (20) is connected to the starting point of the adjacent circular arc groove (20) through the inclined groove (21). A sliding rod (22) is vertically provided on the bushing (9). The sliding rod (22) extends into the rotating groove (18). When the spindle (1) rotates to the angle that matches the booster device (13), the rotating groove (18) can make the booster device (13) move along the sliding groove (15) under the combined action of the limiting rod (16) and the sliding rod (22).

9. The gear adjustment device as described in claim 8, characterized in that, The central angle of the arc groove (20) is 360°(n-1) / n, where n is the number of gears. When the sliding rod (22) slides into the adjacent arc groove (20) through the inclined groove (21), the distance that the gear-increasing sleeve moves is equal to the center distance between the two corresponding arc grooves (20).

10. The gear adjustment device as described in claim 4, 5, 8 or 9, characterized in that, A first planetary gear set (23) and a second planetary gear set (24) are installed at one end of the spindle (1); the first planetary gear and the second planetary gear share a planetary support (2303); the sun gear 1 (2301) in the first planetary gear set (23) is connected to the bushing (9) as a whole, and the sun gear 1 (2301) is rotatably connected to the spindle (1); the gear ring 1 (2304) in the first planetary gear set (23) is rotatably connected to the bushing (9); the sun gear 2 (2401) in the second planetary gear set (24) is keyed to the spindle (1), and the gear ring 2 (2403) in the second planetary gear set (24) is fitted outside the gear ring 1 (2304) in the first planetary gear set (23); the gear ring 2 (2403) is connected to a gear shifting device; a gear shifting knob (25) is fixed at the other end of the spindle (1), and a gear position mark (26) is provided at the end of the bushing (9) corresponding to the gear shifting knob (25).

11. The gear adjustment device as described in claim 6, characterized in that, A first planetary gear set (23) and a second planetary gear set (24) are installed at one end of the spindle (1); the first planetary gear and the second planetary gear share a planetary support (2303); the sun gear 1 (2301) in the first planetary gear set (23) is connected to the bushing (9) as a whole, and the sun gear 1 (2301) is rotatably connected to the spindle (1); the gear ring 1 (2304) in the first planetary gear set (23) is rotatably connected to the bushing (9); the sun gear 2 (2401) in the second planetary gear set (24) is keyed to the spindle (1), and the gear ring 2 (2403) in the second planetary gear set (24) is fitted outside the gear ring 1 (2304) in the first planetary gear set (23); the gear ring 2 (2403) is connected to a gear shifting device, and a gear shifting knob (25) is fixed at the other end of the spindle (1), and a gear position mark (26) is provided at the end of the bushing (9) corresponding to the gear shifting knob (25).

12. The gear adjustment device as described in claim 7, characterized in that, A first planetary gear set (23) and a second planetary gear set (24) are installed at one end of the spindle (1); the first planetary gear and the second planetary gear share a planetary support (2303); the sun gear 1 (2301) in the first planetary gear set (23) is connected to the bushing (9) as a whole, and the sun gear 1 (2301) is rotatably connected to the spindle (1); the gear ring 1 (2304) in the first planetary gear set (23) is rotatably connected to the bushing (9); the sun gear 2 (2401) in the second planetary gear set (24) is keyed to the spindle (1), and the gear ring 2 (2403) in the second planetary gear set (24) is fitted outside the gear ring 1 (2304) in the first planetary gear set (23); the gear ring 2 (2403) is connected to a gear shifting device, and a gear shifting knob (25) is fixed at the other end of the spindle (1), and a gear position mark (26) is provided at the end of the bushing (9) corresponding to the gear shifting knob (25).

13. The gear adjustment device as described in claim 4, 5, 8, 9, 11 or 12, characterized in that, One or more positioning grooves (27) are provided on the inner side of one end of the bushing (9), and the spindle (1) is provided with elastic clips (28) that cooperate with the positioning grooves (27). The elastic clips (28) can enter or leave the positioning grooves (27) when the spindle (1) rotates.

14. The gear adjustment device as described in claim 10, characterized in that, One or more positioning grooves (27) are provided on the inner side of one end of the bushing (9), and the spindle (1) is provided with elastic clips (28) that cooperate with the positioning grooves (27). The elastic clips (28) can enter or leave the positioning grooves (27) when the spindle (1) rotates.

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