A transmission device for a bicycle

Abstract

The invention discloses a transmission device for a bicycle, comprising a reverse double crank mechanism and a speed-increasing direction-changing mechanism, wherein the reverse double crank mechanism comprises a driving crank, a connecting rod, a driven crank and a frame, and the speed-increasing direction-changing mechanism comprises an internal gear, an idler wheel and an external gear, wherein one end of the driving crank is fixedly connected to the middle shaft, and the other end is provided with a screw hole and screwed to a first pin shaft, the outer circle of the first pin shaft is hinged to the connecting rod, and the end is provided with an axial screw hole and screwed to a footboard, and the other end of the connecting rod is hinged to the end face of the internal gear, and the hinge point and the rotation center point of the internal gear form a driven crank, the outer side of the idler wheel meshes with the internal gear, and the inner side meshes with the external gear, and the internal gear drives the external gear to rotate through the idler wheel, and the number of teeth of the internal gear is more than that of the external gear, and the inner hole of the external gear is connected to the rear wheel hub through an overrunning clutch. With the above structure, through two changes of direction, the transmission of the rear wheel and the footboard in the same direction, without a "dead point", and with speed increase is realized.

Description

Technical Field

[0001] The invention relates to a bicycle, in particular to a transmission device of a bicycle. Background Art

[0002] At present, most bicycle transmission devices adopt sprocket chain transmission mechanism. The technology of sprocket chain transmission mechanism is mature. The driving sprocket is installed on the middle shaft, and the driven sprocket is installed on the hub of the rear wheel. The front wheel is steering, the rear wheel is driven, and the seat is located in the middle. The structure is reasonably arranged and suitable for occasions with harsh environmental conditions. It also has the characteristics of long service life, strong load-bearing capacity, large transmission ratio, and obvious speed increase. However, after long-term use, it is easy to wear and there are disadvantages of tooth jumping and chain derailment. In response to the phenomenon of tooth skipping and chain off, relevant technicians have designed various chainless bicycles, which can be roughly summarized as follows: First, the sprocket chain transmission is changed to a cable or synchronous belt. Although there is no phenomenon of tooth skipping and chain off, the cable and synchronous belt are not suitable for occasions with harsh environmental conditions, otherwise their lifespan is not long; second, the sprocket chain transmission is changed to a bevel gear transmission. Due to space limitations, the transmission ratio is relatively small, the speed increase is not obvious, and it is more laborious; third, the active pedal is directly installed on the rear axle, the seat cushion is located above the rear wheel, the distance between the seat cushion and the handlebar becomes farther, and the front wheel becomes smaller, resulting in an unreasonable structural layout, which cannot give full play to the advantages of traditional bicycles. Therefore, the technology of existing chainless bicycles is not very mature, and there are always problems of one kind or another.

[0003] Therefore, the inventor hopes to study a chainless bicycle to overcome the defects of the above-mentioned existing chainless bicycles, and the transmission device is one of the key technologies. Summary of the invention

[0004] Aiming at the shortcomings and deficiencies of the prior art of chainless bicycles, the present invention provides a chainless bicycle which can maintain the advantages of traditional bicycles while avoiding the phenomenon of tooth jumping and chain falling off in sprocket and chain transmission.

[0005] In view of the shortcomings and deficiencies of the existing chainless bicycle technology, the present invention provides a transmission mechanism that can achieve both continuous rotation and speed increase.

[0006] To achieve the above object, the present invention provides a transmission device for a bicycle, characterized in that it includes a reverse double crank mechanism and a speed-increasing and direction-changing mechanism, wherein the reverse double crank mechanism includes a driving crank, a connecting rod, a driven crank and a frame, the A end of the driving crank is provided with a square hole fixedly connected to the square head of the middle shaft, the speed-increasing and direction-changing mechanism includes an internal gear, an idler wheel, an external gear and a fixed support frame, the outer side of the idler wheel and the internal gear form an internal meshing gear pair, and the inner side and the external gear form an external meshing gear pair, the connecting rod is arranged on the driving crank The outer side of the handle and the internal gear is hinged to the B end of the active crank through the first pin shaft at one end, and hinged to the end face of the internal gear through the second pin shaft at the other end, and the hinge point C of the internal gear and the connecting rod and the rotation center point D of the internal gear form a driven crank. The lengths of the active crank and the driven crank are equal, and the lengths of the connecting rod and the frame are equal and non-parallel, forming a reverse double crank mechanism ABCD. A circular hole is provided at one end of the fixed support frame and a boss is provided at the other end. The inner hole of the internal gear is hinged to the outer circle of the boss of the fixed support frame through a rolling bearing.

[0007] The beneficial effects of the present invention are as follows: by adopting the above structure, the reverse double crank mechanism ABCD can realize the direction of the driven crank opposite to that of the active crank, and can rotate continuously without a "dead point", and at the same time provide conditions for the subsequent speed-increasing direction-changing mechanism to change direction again; the axes of the internal gear, the idler wheel and the external gear are all fixed, and the number of teeth of the idler wheel does not affect the size of the transmission ratio, but the direction of the external gear is changed. The number of teeth of the internal gear is greater than that of the external gear, and the internal gear is active and the external gear is driven, and the transmission ratio is greater than 1, thereby realizing the purpose of speed-increasing transmission, saving riding effort, and the rear wheel and the pedal having the same direction.

[0008] The present invention can be further configured such that a square hole is provided in the axial direction of the boss of the fixed support frame, and the square hole is fixedly connected with the square head of the rear axle.

[0009] By adopting the above further arrangement, the square hole and the square head are matched and fixedly connected, which can make assembly and disassembly convenient and the connection reliable.

[0010] The present invention can be further configured such that an overrunning clutch is provided in the inner hole of the external gear, and the overrunning clutch includes an inner ratchet, a pawl, a connecting sleeve and a spring, the teeth of the inner ratchet are evenly distributed on the inner hole wall of the external gear, the inner end of the pawl is hinged to the end face of the connecting sleeve, and the outer end is in conflict with the tooth surface of the inner ratchet, one end of the spring is fixed to the end face of the connecting sleeve, and the other end is in conflict with the side face of the pawl, and the inner hole of the connecting sleeve is provided with an internal thread which forms a threaded connection with the external thread of the rear wheel hub.

[0011] By adopting the above-mentioned further arrangement and utilizing the characteristics of the overrunning clutch, automatic engagement and disengagement can be achieved, namely: when the rotation speed of the outer gear is greater than the rotation speed of the rear wheel hub, it is automatically engaged, and the connecting sleeve is driven to rotate through the inner ratchet and the pawl, so that the rear wheel hub rotates; when the rotation speed of the outer gear is less than the rotation speed of the rear wheel hub or the two rotate in opposite directions, they are automatically disengaged, and the pawl slides over the tooth surface of the inner ratchet without affecting the original rotation of the rear wheel hub.

[0012] The present invention can be further configured such that the idler wheel is hinged to the middle journal of the third pin shaft through a rolling bearing, one end of the third pin shaft passes through the circular hole of the fixed support frame and is fixed to the retaining spring, and the other end passes through the inner hole of the rolling bearing, the sleeve and the radial through hole at the lower end of the rear upper right fork in sequence, and is screwed and fixed with a nut.

[0013] By adopting the above further arrangement, the third pin shaft is fixed, the idler wheel can rotate around the third pin shaft, the sleeve and the nut axially position the idler wheel, and the rolling bearing converts sliding friction into rolling friction, which has low friction and makes the idler wheel rotate more easily; the frame is connected to the third pin shaft, which improves the strength, rigidity and stability of the whole vehicle.

[0014] The present invention can be further configured such that an inner end of the first pin shaft is provided with an external thread which is threadedly connected to the internal thread hole of the active crank, an outer end is provided with an internal threaded blind hole in the axial direction which is threadedly connected to the external thread of the footboard, and a journal is provided in the middle part which is hinged to the connecting rod through a rolling bearing.

[0015] By adopting the above further arrangement, the connecting rod and the footboard are installed on the first pin shaft, so that the rotation of the footboard drives the connecting rod to rotate, and the connecting rod will not get stuck during the planar movement; the threaded connection is convenient for loading and unloading; the rolling bearing converts sliding friction into rolling friction, the friction force is small, and the connecting rod moves easier. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 The present invention is applied to a structural principle diagram of a chainless bicycle;

[0017] Figure 2 It is a schematic diagram of the present invention applied to a chainless bicycle transmission device;

[0018] Figure 3 It is a structural diagram of a reverse double crank mechanism of a specific embodiment of the present invention;

[0019] Figure 4 It is a structural diagram of a speed-increasing and direction-changing mechanism according to a specific embodiment of the present invention;

[0020] Figure 5 It is a structural diagram of an overrunning clutch according to a specific embodiment of the present invention;

[0021] Figure 6A structural diagram of an internal gear according to a specific embodiment of the present invention;

[0022] Figure 7 It is a structural diagram of an idler wheel according to a specific embodiment of the present invention. DETAILED DESCRIPTION

[0023] like Figure 2 , 3 , 4, 5, 6, and 7, the present invention provides a transmission device for a bicycle, including a reverse double crank mechanism 21 and a speed-increasing direction-changing mechanism 22, wherein the reverse double crank mechanism 21 includes a driving crank 211, a connecting rod 212, a driven crank 213, and a frame 214, wherein the A end of the driving crank 211 is provided with a square hole fixedly connected to the square head of the middle shaft 4, wherein the speed-increasing direction-changing mechanism 22 includes an internal gear 221, an idler wheel 222, an external gear 223, and a fixed support frame 224, wherein the outer side of the idler wheel 222 forms an internal meshing gear pair with the internal gear 221, and the inner side forms an external meshing gear pair with the external gear 223, wherein the connecting rod 212 is arranged between the driving crank 211 and the internal gear The outer side of 221 has one end hinged to the B end of the active crank 211 through the first pin shaft 215, and the other end hinged to the end face of the internal gear 221 through the second pin shaft 216, and the hinge point C between the internal gear 221 and the connecting rod 212 and the rotation center point D of the internal gear 221 form a driven crank 213, the lengths of the active crank 211 and the driven crank 213 are equal, the lengths of the connecting rod 212 and the frame 214 are equal and not parallel, forming a reverse double crank mechanism ABCD21, one end of the fixed support frame 224 is provided with a circular hole, and the other end is provided with a boss 2241, the inner hole of the internal gear 221 is hinged to the outer circle of the boss 2241 of the fixed support frame 224 through a rolling bearing. With the above structure, the reverse double crank mechanism ABCD21 can realize the direction of the driven crank 213 opposite to the driving crank 211, and continuously rotate without a "dead point", and at the same time provide conditions for the subsequent speed-increasing direction-changing mechanism 22 to change direction again; the axes of the internal gear 221, the idler wheel 222 and the external gear 223 are all fixed, and the number of teeth of the idler wheel 222 does not affect the size of the transmission ratio, but changes the direction of the external gear 223. The number of teeth of the internal gear 221 is more than the number of teeth of the external gear 223, and the internal gear 221 is active, and the external gear 223 is driven, and the transmission ratio is greater than 1, thereby achieving the purpose of speed-increasing transmission, saving effort in riding, and the wheel 3 and the pedal 217 have the same direction. With the above further configuration, the number of idler wheels 222 can be multiple, and one is preferred in the present invention, which can reduce costs and reduce weight.

[0024] The present invention can be further configured such that the boss 2241 of the fixed support frame 224 is provided with a square hole in the axial direction, and the square hole is fixedly connected with the square head of the rear axle 5. With the above further configuration, the square hole is fixedly connected with the square head, which can facilitate assembly and disassembly and ensure reliable connection.

[0025] The present invention can be further configured such that an overrunning clutch 6 is provided in the inner hole of the external gear 223, and the overrunning clutch 6 includes an inner ratchet 61, a pawl 62, a connecting sleeve 63 and a spring 64. The teeth of the inner ratchet 61 are evenly distributed on the inner hole wall of the external gear 223, the inner end of the pawl 62 is hinged to the end face of the connecting sleeve 63, and the outer end is in conflict with the tooth surface of the inner ratchet 61. One end of the spring 64 is fixed to the end face of the connecting sleeve 63, and the other end is in conflict with the side face of the pawl 62. The inner hole of the connecting sleeve 63 is provided with an internal thread which is threadedly connected with the external thread of the rear wheel hub 321. By adopting the above structure and utilizing the characteristics of the overrunning clutch 6, automatic engagement and disengagement are achieved, that is, when the rotation speed of the outer gear 223 is greater than the rotation speed of the rear wheel hub 321, it is automatically engaged, and the connecting sleeve 63 is driven to rotate through the inner ratchet 61 and the pawl 62, so that the rear wheel hub 321 rotates; when the rotation speed of the outer gear 223 is less than the rotation speed of the rear wheel hub 321 or the two rotate in opposite directions, it is automatically disengaged, and the pawl 62 slides on the tooth surface of the inner ratchet 61 without affecting the original rotation of the rear wheel hub 321. By adopting the above further configuration, the number of the pawl 62 and the spring 64 can be one, two or more, and two are preferred in the present invention, on the one hand, to balance the force and improve the stability of the transmission, and on the other hand, to make the structure as simple as possible.

[0026] The present invention can be further configured such that the idler wheel 222 is hinged to the middle journal of the third pin shaft 225 through a rolling bearing, one end of the third pin shaft 225 passes through the circular hole of the fixed support frame 224 and is fixed to the retaining spring 226, and the other end passes through the inner hole of the rolling bearing, the sleeve 228 and the radial through hole of the lower end of the rear upper right fork 142 in sequence, and is screwed and fixed with a nut. With the above structure, the third pin shaft 225 is fixed, and the idler wheel 222 can rotate around the third pin shaft 225. The sleeve 227 and the nut position the idler wheel 222 axially, and the rolling bearing converts sliding friction into rolling friction, with low friction, making the idler wheel 222 rotate more easily; the frame 1 is connected to the third pin shaft 225, which improves the strength, rigidity and stability of the whole vehicle.

[0027] The present invention can be further configured such that an inner end of the first pin shaft 215 is provided with an external thread to form a threaded connection with the internal thread hole of the active crank 211, an axial direction of an outer end is provided with an internal thread blind hole to form a threaded connection with the external thread of the pedal board 217, and a journal is provided in the middle to be hinged with the connecting rod 212 through a rolling bearing. With the above structure, the connecting rod 212 and the pedal board 217 are installed on the first pin shaft 215, so that the pedal board 217 rotates to drive the connecting rod 212 to rotate, and the connecting rod 212 will not get stuck during the planar motion; the threaded connection is easy to assemble and disassemble; the rolling bearing converts the sliding friction into rolling friction, and the friction force is small, so that the connecting rod 212 moves more easily.

[0028] like Figure 1As shown, the present invention is applied to a specific technical solution of a chainless bicycle, including a frame 1, a transmission device 2 and a wheel 3. The frame 1 includes an upper tube 11, a lower tube 12, a seat tube 13, a rear seat fork 14 and a rear lower fork 15. The transmission device 2 includes a reverse double crank mechanism 21 and a speed-increasing direction-changing mechanism 22. The wheel 3 includes a front wheel 31 and a rear wheel 32. A circular hole is provided at the connection between the lower tube 12 and the seat tube 13, and is hinged to the outer circle of the middle shaft 4. The upper fork 14 includes a left upper fork 141 and a right upper fork 142, and the lower fork 15 includes a left lower fork 151 and a right lower fork 152. A connecting hole is provided at the intersection of the left upper fork 141 and the left lower fork 151, which is fixedly connected to one end of the rear axle 5. A radial through hole is provided at the middle and lower part of the right upper fork 142 and a radial through hole is provided at the end of the right lower fork 152, which are fixedly connected by screws. The transmission device 2 is installed on the right outer side of the frame 1. The above structure is not only conducive to the installation of the transmission device 2, but also conducive to the flexible operation of the entire transmission system without being stuck.

Claims

1. A transmission device for a bicycle, characterized in that: The invention comprises a reverse double crank mechanism and a speed-increasing and changing mechanism, wherein the reverse double crank mechanism comprises a driving crank, a connecting rod, a driven crank and a frame, the A end of the driving crank is provided with a square hole fixedly connected with the square head of the middle shaft, the speed-increasing and changing mechanism comprises an internal gear, an idler wheel, an external gear and a fixed support frame, the outer side of the idler wheel and the internal gear form an internal meshing gear pair, and the inner side and the external gear form an external meshing gear pair, the axes of the internal gear, the idler wheel and the external gear are all fixed, and the number of teeth of the internal gear is greater than that of the external gear, the connecting rod It is arranged on the outside of the active crank and the internal gear, one end is hinged to the B end of the active crank through the first pin shaft, and the other end is hinged to the end face of the internal gear through the second pin shaft. The hinge point C and the rotation center point D of the internal gear form a driven crank. The lengths of the active crank and the driven crank are equal, and the lengths of the connecting rod and the frame are equal and non-parallel, forming a reverse double crank mechanism ABCD. A circular hole is provided at one end of the fixed support frame and a boss is provided at the other end. The inner hole of the internal gear is hinged to the outer circle of the boss of the fixed support frame through a rolling bearing.

2. A bicycle transmission device according to claim 1, characterized in that: A square hole is provided in the axial direction of the boss of the fixed support frame, and the square hole is matched and fixedly connected with the square head of the rear axle.

3. A bicycle transmission device according to claim 1, characterized in that: An overrunning clutch is provided in the inner hole of the external gear, and the overrunning clutch includes an inner ratchet, a pawl, a connecting sleeve and a spring. The teeth of the inner ratchet are evenly distributed on the inner hole wall of the external gear. The inner end of the pawl is hinged to the end face of the connecting sleeve, and the outer end is in conflict with the tooth surface of the inner ratchet. One end of the spring is fixed to the end face of the connecting sleeve, and the other end is in conflict with the side face of the pawl. The inner hole of the connecting sleeve is provided with an internal thread that forms a threaded connection with the external thread of the rear wheel hub.

4. A bicycle transmission device according to claim 1, characterized in that: The idler wheel is hinged to the middle journal of the third pin shaft through a rolling bearing. One end of the third pin shaft passes through the circular hole of the fixed support frame and is fixed with the retaining spring, and the other end passes through the inner hole of the rolling bearing, the sleeve and the radial through hole at the lower end of the rear upper right fork in sequence and is screwed and fixed with a nut.

5. A bicycle transmission device according to claim 1, characterized in that: The inner end of the first pin shaft is provided with an external thread which is threadedly connected to the internal thread hole of the active crank, the axial direction of the outer end is provided with an internal thread blind hole which is threadedly connected to the external thread of the pedal, and the middle part is provided with a journal which is hinged to the connecting rod through a rolling bearing.

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