JP2006306360A - Bicycle transmission - Google Patents

Abstract

Provided is an internal bicycle transmission device that is simple in structure and can be attached to various bicycles for general use.
A plurality of front rotating bodies 2, 3, and 4 corresponding to the number of shift stages are arranged side by side around a crank rotating body 1 fixed to a crank shaft that is rotated by a pedaling force of a pedal, and are provided at the rear of the crank shaft. The counter-rotating shaft 5 supports the rear rotating bodies 6, 7, 8 interlocking with the front rotating bodies 2, 3, 4 at a predetermined speed ratio so as to be integrally rotatable. , 3 and 4, ratchet pawls 16, 17 and 18 are provided, and ratchet teeth 19 with which the ratchet pawls 16, 17 and 18 engage are formed on the inner peripheral side of each of the front rotating bodies 2, 3 and 4. In accordance with the operation of the switching member 20 that contacts and separates the claws 17, 18, the ratchet claws 17, 18 are engaged with and disengaged from the ratchet teeth 19, and the front rotating bodies 2, 3, 4 that transmit the driving force are switched to change speed.
[Selection] Figure 1

Description

  The present invention relates to a transmission provided on a crankshaft portion of a bicycle, which is provided with a driving force transmission mechanism composed of a crankshaft and a countershaft.

  In general, as a bicycle transmission that adjusts the pedal depression load according to the gradient of the road surface on which it travels, sports bicycles are equipped with exterior types that change chains on multiple stages of sprockets. In many cases, bicycles for street riding are equipped with an interior type using a planetary gear mechanism that can perform a shifting operation easily and smoothly.

  As this interior transmission, the following Patent Document 1 includes a gear case incorporated in a frame and a crankshaft that is rotatable by a pedaling force of a pedal, a rotatable rotating body is provided, and a sprocket is fixed to one side thereof, A plurality of planetary gears are pivotally supported on a carrier that rotates integrally with the crankshaft, and rotatable sun gears are engaged with the inner sides of the planetary gears. A ratchet mechanism that absorbs the rotational speed difference between the carrier and the driven rotating body is provided by meshing the internal gear provided on the body, and the switching operation of the one-way clutch that allows / blocks the rotation of the sun gear at each stage is performed. Thus, there is described a gear that changes speed by switching an internal gear that is accelerated with respect to the crankshaft.

  In Patent Document 2 below, a sprocket and a large-diameter sun gear are integrally formed on one side and the other side so as to be rotatable with respect to a gear case fixed to a frame and a crankshaft rotating by a pedaling force. The planetary gear is supported by a carrier that rotates integrally with the crankshaft, and a small-diameter sun gear that can rotate relative to the crankshaft is engaged inside the large-diameter step of the planetary gear. The planetary gear is meshed with the large-diameter sun gear inside the small-diameter step, and the planetary gear is meshed with the internal gear on the outside of each planetary gear to absorb the difference in rotational speed between the small-diameter sun gear and the driven rotor. A ratchet mechanism is provided to change the speed of the sun gear that is accelerated relative to the crankshaft by switching the one-way clutch that allows / blocks rotation of the internal gear of each stage relative to the gear case. Umono have been described.

JP-A-6-263081 JP-A-6-298153

  However, the transmission as described above requires a large number of parts constituting a one-way clutch corresponding to the ratchet mechanism, sun gears or internal gears of each stage, and there is a problem that the structure becomes complicated and the speed change. There is also a problem that it cannot be attached later to a bicycle without a device.

  SUMMARY OF THE INVENTION An object of the present invention is to provide an internal bicycle transmission that has a simple structure and is universally attached to various bicycles.

  In order to solve the above-mentioned problems, the present invention provides a plurality of front-side rotary bodies corresponding to the number of shift stages arranged side by side around a crank rotary body fixed to a crankshaft that is rotated by a pedal effort, and is provided at the rear of the crankshaft. The counter-rotating shaft supports the rear rotating body interlocking with each front rotating body at a predetermined speed ratio so as to be integrally rotatable. The crank rotating body is provided with a ratchet claw corresponding to each front rotating body, and the ratchet claw is engaged. The mating ratchet teeth are formed on the inner circumference of each front rotating body, and the ratchet pawls are engaged with and disengaged from the ratchet teeth when the switching member that contacts and separates from the ratchet pawls is transmitted to the rear rotating body. By switching the front rotating body, the speed ratio of the rotation transmitted from the crankshaft to the rear wheel drive sprocket is changed to change the speed.

  In the above transmission, it is preferable that the front rotating body and the rear rotating body be gears and mesh with each other. Also, the front rotator and the rear rotator may be sprockets, and a chain may be spanned between them, or the front rotator and the rear rotator may be toothed pulleys, and a toothed belt may be spanned between them. Good.

  In addition, an internal gear is provided in one of the front rotating bodies, and any of the rear rotating bodies that are gears is engaged with the internal gear, and the other front rotating bodies and rear rotating bodies that are gears are connected to the intermediate gear. May be engaged with each other, and a toothed belt may be wound around another front rotating body and a rear rotating body that are toothed pulleys.

  In addition, in order to prevent the noise caused by the sliding between the ratchet pawl and the ratchet tooth, only the ratchet pawl that transmits the driving force meshes with the ratchet tooth, and the meshing between the other ratchet pawl and the ratchet tooth is released. May be.

  Further, as the switching pedal provided on the crank arm is depressed, the switching member may be rotated to perform the speed change operation.

  In the bicycle transmission according to the present invention, a plurality of the front rotating bodies and the rear rotating bodies corresponding to the number of shift stages are linked at a predetermined speed ratio, and the ratchet pawl is turned into the ratchet teeth in accordance with the operation of the switching member. Since it is engaged and disengaged to change the speed by switching the front rotating body that transmits the driving force to the rear rotating body, there is no need to provide multi-stage planetary gears, sun gears, internal gears, etc., and to switch these transmission paths. This simplifies the manufacturing cost, improves the reliability during use, and can be easily attached to an existing bicycle.

  Hereinafter, a bicycle transmission according to an embodiment of the present invention will be described with reference to the accompanying drawings.

  In the transmission according to the first embodiment, as shown in FIGS. 1 and 2, a crankcase 53 integrated with a crank arm 52 is attached to a crankshaft 51 that is rotated by a pedal effort when attached to a bicycle. The boss 53a is fitted and fixed, and the crank rotating body 1 is provided so as to be rotatable integrally therewith.

  Around the crank rotating body 1, three front rotating bodies 2, 3, 4 for low speed, high speed and medium speed are sequentially arranged from the right side to the left side in correspondence with the three speeds. Yes. The front rotating bodies 2, 3, and 4 are gears having teeth on the outer periphery, and the outer diameter and the number of teeth are set according to the rotational speed to be transmitted.

  The front rotators 2 and 4 are rotatably supported by the crank rotator 1 via balls, and the front rotator 3 is rotatably fitted to a step portion of the front rotator 2. , 3 and 4 are rotatable relative to each other. The crank rotator 1 and the front rotator 4 are composed of a plurality of members such as ball receivers for the convenience of assembly, and are assembled by combining them.

  A countershaft 5 is provided at the rear of the crankshaft 51, and the subshaft 5 allows the rear rotating bodies 6, 7, 8 integrated at the boss portion to be rotatable via the collar 9 and the needle bearing 10. It is supported. The rear rotators 6, 7 and 8 are gears having teeth on the outer periphery, and mesh with the front rotators 2, 3 and 4 so as to interlock with each other at a predetermined speed ratio.

  The front rotators 2, 3, 4 and the rear rotators 6, 7, 8 are housed in an oval gear case 11 that is long in the front-rear direction and the vertical dimension is reduced in the rear direction. It is supported. The left side of the front rotating body 4 protrudes from the gear case 11, and a sprocket 12 for attaching the rear wheel drive chain 55 is attached to the protruding portion.

  On the left side of the gear case 11, a substrate portion 13a of the fixing member 13 that does not rotate is provided, and a cylindrical portion 13b of the fixing member 13 is fitted around the boss 53a of the crankcase 53, and a large lead is switched on the outer periphery. Screws 14 are engraved. The base plate portion 13 a of the fixing member 13 and the gear case 11 are fixed with fixing bolts 15.

  The crank rotator 1 is provided with ratchet claws 16, 17, and 18 that are urged in the projecting direction corresponding to the front rotary bodies 2, 3, and 4, and the tip portions of the ratchet claws 16, 17, and 18 are provided. It engages with ratchet teeth 19 formed on the inner peripheral side of the front rotating bodies 2, 3, 4.

  A ring-shaped switching member 20 is screwed into the switching screw 14, and an arm 22 extended from the disk portion 21 a of the switching body 21 that rotates with respect to the fixing member 13 passes through the switching member 20. is doing. The disc portion 21 a of the switching body 21 is provided with a connecting portion 23 that protrudes to the left side through the opening of the fixing member 13.

  A wire 24 extending from an operation lever attached near the handle or the pedal is connected to the connecting portion 23, and when the wire 24 is pulled in accordance with a speed change operation, the switching member 20 rotates together with the switching body 21 and the crankshaft 51. And move forward and backward with respect to the ratchet claws 17 and 18.

  The facing surfaces of the switching member 20 and the ratchet claws 17 and 18 are inclined so as to slide with each other. When the rear portions of the ratchet claws 17 and 18 are pressed by the switching member 20, the ratchet claws 17 and 18 are moved in the immersion direction. It swings and the engagement with the ratchet teeth 19 is released. The connecting portion 23 and the substrate portion 13 a of the fixing member 13 are connected by a return spring 25 that urges the switching member 20 in a direction away from the ratchet claws 17 and 18.

  The gear case 11 is sandwiched from above and below by an upper chain case 26 fixed to a sleeve that supports the left side of the front rotating body 4 and a lower chain case 27 that is connected to the front portion via a hinge. The rear portion of 26 and the rear portion of the lower chain case 27 are urged in a pulling direction via a tension spring 28.

  In such a transmission, as shown in FIG. 1, when the switching member 20 is in a position retracted to the right side away from the ratchet pawls 17, 18, the ratchet pawls 16, 17, 18 and the respective front rotating bodies 2, 3 , 4 is maintained in engagement with the ratchet teeth 19, so that rotation is transmitted from the crank rotating body 1 rotating together with the crankshaft 51 to the front rotating bodies 2, 3, 4.

  Accordingly, the peripheral speed of the large-diameter front rotary body 3 becomes faster than the peripheral speeds of the small-diameter and medium-diameter front rotary bodies 2 and 4, and the small-diameter rear rotary body 7 meshing with the front-side rotary body 3 is high speed. Therefore, the other rear rotors 6 and 8 integral with the rear rotor 7 also rotate at high speed, and this rotation is transmitted to the sprocket 12 via the front rotor 4 so that the rear wheels are driven at high speed. Is done.

  At this time, due to the sliding motion of the ratchet pawls 16 and 18 with respect to the ratchet teeth 19, the front rotating bodies 2 and 4 are rotated at a relatively high speed with respect to the crank rotating body 1, and the crank rotating body 1 and the front rotating body are rotated. No driving force is transmitted to 2 and 4.

  On the other hand, as shown in FIG. 3, when the switching member 20 is rotated by one step and advanced to the intermediate position in accordance with the speed change operation, the switching member 20 presses and swings the ratchet pawl 17, Since the engagement of the front rotating body 3 with the ratchet teeth 19 is released, the rotation transmission from the crank rotating body 1 to the front rotating body 3 is cut off and transmitted from the crank rotating body 1 to the front rotating body 4 having an intermediate diameter. The sprocket 12 is rotated by the driving force to drive the rear wheels at medium speed.

  Further, as shown in FIG. 4, when the switching member 20 is rotated in two stages and moved forward to the left side of the switching screw 14, the switching member 20 presses and swings the ratchet pawl 18 of the front rotating body 4. Since the engagement between the claw 18 and the ratchet teeth 19 of the front rotating body 4 is also released, the rotation transmission from the crank rotating body 1 to the front rotating body 4 is also cut off.

  In this state, the rotation transmitted from the crank rotator 1 to the small-diameter front rotator 2 causes the large-diameter rear rotator 6 meshing with the front rotator 2 to rotate at a low speed. The other integrated rear rotating bodies 7 and 8 also rotate at a low speed, and this rotation is transmitted to the sprocket 12 via the front rotating body 4 so that the rear wheels are driven at a low speed.

  When the reverse speed change operation is performed from this state, the switching member 20 is reversely rotated by the urging force of the return spring 25 and is moved back to the right so as to be sequentially separated from the ratchet pawls 18, 17. And the ratchet teeth 19 of the front rotating bodies 4 and 3 are engaged again, so that the rear wheels are driven at medium and high speeds.

  In this transmission, as shown in FIG. 2, when the crank arm 52 is rotated by strongly stepping on the pedal, the rear part of the lower chain case 27 is pushed down by the moment acting on the gear case 11. Thereafter, the lower chain case 27 and the gear case 11 are returned to their original positions by the action of the tension spring 28, and this operation is repeated to reduce the load during traveling.

  By the way, in order to provide such a traveling load reducing function, the chain case 26 is fixed as a single unit, the gear case 11 is rotatably fitted in the chain case 26, and the rear portion of the gear case 11 and the chain case 26 are connected to a tension spring. You may make it connect by 28. FIG.

  Next, another embodiment in which the configuration of the first embodiment is partially changed will be described.

  In the transmission according to the second embodiment shown in FIG. 5, the auxiliary shaft 5 is positioned rearward of the first embodiment, and the front rotating bodies 2, 3, 4 and the rear rotating bodies 6, 7, 8 are arranged. The rear rotator 8 is engaged with the rear wheel drive chain 55 as a sprocket, and the interlocking chain 29 is stretched between the front rotators 2 and 3 and the rear rotators 6 and 7.

  In the transmission according to the third embodiment shown in FIG. 6, the front rotating bodies 2, 3, 4 and the rear rotating bodies 6, 7, 8 are replaced with the gears of the first embodiment with a toothed pulley. The toothed belt 30 is stretched over these.

  Even in this configuration, as in the transmission according to the first embodiment, the internal speed of the crankshaft 51 is set to a medium speed, and an internal type three-speed transmission that can shift to a high speed and a low speed on the basis of this is used as a reference. Function.

  Further, in the transmission according to the fourth embodiment shown in FIG. 7, an internal gear 31 is provided so as to be able to rotate integrally with the front rotating body 4 and the sprocket 12, and the rear rotating body 8 is engaged with the internal gear 31, thereby 2 and 3 and the rear rotating bodies 6 and 7 are configured to mesh with each other via an intermediate gear 32 in order to align the rotation direction.

  Further, in the transmission according to the fifth embodiment shown in FIG. 8, as in the fourth embodiment, the internal gear 31 is provided so as to be able to rotate integrally with the front rotating body 4 and the sprocket 12, and the rear rotating body 8 is disposed inside. The toothed belt 30 is stretched around the front rotating bodies 2 and 3 and the rear rotating bodies 6 and 7 by meshing with the gear 31.

  In these transmissions, the number of teeth of the meshing members and the switching member 20 are set so that the crankshaft 51 rotates as a high speed and functions as an internal three-speed transmission that shifts to a medium speed and a low speed based on this. Although the operating direction is set, the final gear ratio is determined by the gear ratio of the sprocket 12 on the crankshaft 51 side and the sprocket on the rear wheel side.

  By the way, in the transmissions described in the above embodiments, slip occurs between the ratchet pawls 16 and 18 and the ratchet teeth 19 when driven at high speed, and the ratchet pawl 16 and ratchet teeth 19 occur when driven at medium speed. Slip occurs between the two. Accompanied by this sliding, a ticking sound is generated, and particularly at high speeds, dissonant sounds with different rhythms may be felt annoying. An embodiment in which such noise prevention measures are taken is shown below.

  In the transmission according to the sixth embodiment shown in FIGS. 9 to 12, a crest 20 a and a trough 20 b are formed on the outer periphery of the switching member 20. In the high-speed transmission state shown in FIGS. 9 and 10, the high-speed transmission ratchet pawl 17 is fitted into the valley 20b and meshed with the front rotating body 3, and the other ratchet pawls 16 and 18 are engaged with the peak 20a. By being pushed, the meshing with the front rotating bodies 2 and 4 is released.

  Next, when the switching member 20 is moved to the left by one step in accordance with the speed change operation, the medium speed transmission ratchet pawl 18 is fitted into the valley portion 20b and rotated forward. The other ratchet claws 16 and 17 are engaged with the body 4 and are pushed by the peak portion 20a, and the engagement with the front rotating bodies 2 and 3 is released.

  Further, when the switching member 20 is moved to the left by two stages in accordance with the speed change operation, the low-speed transmission ratchet pawl 16 is disengaged from the switching member 20 and meshes with the front rotating body 2. The other ratchet claws 17 and 18 are pushed by the crest 20a, and the meshing with the front rotating bodies 3 and 4 is released.

  Thus, in the above transmission, only the ratchet pawls 16, 17, 18 that transmit driving force mesh with the ratchet teeth 19, and the meshing between the other ratchet teeth 19 and the ratchet teeth 19 is released. Even when driving at high speeds and medium speeds, no noise is generated and the vehicle can travel comfortably.

  In the transmission according to the seventh embodiment shown in FIGS. 13 to 18, the switching member 20 rotates in the circumferential direction of the crankshaft 51 without moving in the axial direction of the crankshaft 51. . As shown in FIG. 14A, the switching member 20 has a through-hole portion 20c with respect to the high-speed ratchet pawl 17 and has a through-hole portion 20c with respect to the medium-speed ratchet pawl 18 as shown in FIG. As shown in FIG. 14C, the through-hole portion 20 c and the short middle step portion 20 d are respectively formed on the low-speed ratchet pawl 16.

  In the high-speed transmission state shown in FIG. 13, the high-speed transmission ratchet pawl 17 is fitted into the through-hole portion 20c and meshed with the front rotating body 3, and the other ratchet pawls 16 and 18 are pushed by the middle step portion 20d. Thus, the meshing with the front rotating bodies 2 and 4 is released.

  Next, when the switching member 20 is rotated by one step in accordance with the speed change operation to be in the medium speed transmission state shown in FIG. 15, the medium speed transmission ratchet pawl 18 is fitted into the through-hole portion 20 c and the front rotating body is moved. 4, the high-speed transmission ratchet pawl 17 is pushed by the outer periphery of the switching member 20, and the low-speed transmission ratchet pawl 16 is pushed by the middle step portion 20 d, and the meshing with the front rotating bodies 2 and 3 is released. It becomes a state.

  Further, when the switching member 20 is rotated in two stages in accordance with the speed change operation to enter the low speed transmission state shown in FIG. Then, the other ratchet claws 17 and 18 are pushed by the outer periphery of the switching member 20, respectively, so that the meshing with the front rotating bodies 3 and 4 is released.

  In such a transmission as well as in the sixth embodiment, it is possible to prevent noise during driving at a high speed and a medium speed, and the switching member 20 is provided with a middle step portion 20d. When shifting to the high speed side, the meshing between the ratchet pawls 16 and 18 and the ratchet teeth 19 for transmitting medium and low speeds is quickly released, so that noise during shifting is also prevented.

  As shown in FIG. 17, the transmission includes a kick type switching mechanism that performs a speed change operation by depressing the switching pedal 33. In this switching mechanism, the switching pedal 33 is swingably supported by the crank arm 52 via the support shaft 34, and is decelerated when the front stepping portion 33a is depressed with the foot placed on the pedal 56, and the rear stepping portion 33b is moved. The speed increases when you step on.

  An engagement notch 33 c is formed at the rear end of the switching pedal 33, and an engagement shaft 36 provided on an outer protruding piece 35 a of the switching ring 35 that rotates relative to the crankcase 53 is slidable in the engagement notch 33 c. Is being laid in.

  As shown in FIG. 18, the switching ring 35 is rotatably fitted on the outer periphery of a sliding contact member 37 fitted to the crankcase 53, and around the boss 53a, an inner projecting piece 35b of the switching ring 35 is provided. A pair of fan-shaped attachment plates 38 that are pushed and rotated are provided. A pressing spring 39 is provided between the rear portions of the mounting plate 38, and the pair of fan-shaped mounting plates 38 are pressed against the stopper 53 b of the crankcase 53 by the biasing force.

  Each mounting plate 38 is provided with a ratchet claw 40, the sliding contact member 37 is engaged with a pressing projection 37 a that presses the proximal end of the ratchet claw 40, and the flange of the switching member 20 is engaged with the tip of the ratchet claw 40. Ratchet teeth 20e are provided respectively.

  The meshing between the ratchet pawl 40 and the ratchet teeth 20e is released when the mounting plate 38 is pressed against the stopper 53b, and one mounting plate 38 rotates together with the switching ring 35 as the switching pedal 33 is depressed. When the pressing of the ratchet pawl 40 by the pressing protrusion 37a is released, the ratchet pawl 40 meshes with the ratchet teeth 20e, and the switching member 20 rotates by a predetermined angle with respect to the boss 53a.

  By providing such a kick-type switching mechanism, you can change gears by just moving your feet without looking at your hands, you can operate like a bicycle with a conventional transmission, and you can connect the brake wire from the handle to the frame. The troublesome extension of the transmission wire is also eliminated.

1 is a cross-sectional plan view showing a high-speed transmission state of a transmission according to a first embodiment of the invention. Vertical right side view showing the meshing state of the above transmission from the crank arm side Cross-sectional plan view showing the medium speed transmission state of the above transmission Cross-sectional plan view showing the low-speed transmission state of the above transmission Transverse plan view showing a high-speed transmission state of a transmission according to a second embodiment of the present invention. Transverse plan view showing a high-speed transmission state of a transmission according to a third embodiment of the present invention. Transverse plan view showing a high-speed transmission state of a transmission according to a fourth embodiment of the present invention. Transverse plan view showing a high-speed transmission state of a transmission according to a fifth embodiment of the present invention. Transverse plan view showing a high-speed transmission state of a transmission according to a sixth embodiment of the present invention. Vertical right side view showing the meshing state of the above transmission from the crank arm side Cross-sectional plan view showing the medium speed transmission state of the above transmission Cross-sectional plan view showing the low-speed transmission state of the above transmission Transverse plan view showing a high-speed transmission state of a transmission according to a seventh embodiment of the invention Side view showing relationship between each ratchet pawl and switching member Cross-sectional plan view showing the medium speed transmission state of the above transmission Cross-sectional plan view showing the low-speed transmission state of the above transmission Right view showing the operation of the switching pedal of the kick type switching mechanism Left view showing the internal structure of the kick type switching mechanism

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Crank rotation body 2,3,4 Front rotation body 5 Countershaft 6,7,8 Rear rotation body 9 Collar 10 Needle bearing 11 Gear case 12 Sprocket 13 Fixing member 13a Substrate part 13b Cylindrical part 14 Switch screw 15 Fixing bolt 16, 17, 18 Ratchet claw 19 Ratchet teeth 20 Switching member 20a Mountain portion 20b Valley portion 20c Through hole portion 20d Middle step portion 20e Ratchet teeth 21 Switching body 21a Disk portion 22 Arm 23 Connecting portion 24 Wire 25 Return spring 26, 27 Chain case 28 Tension spring 29 Chain 30 Toothed belt 31 Internal gear 32 Intermediate gear 33 Switching pedal 33a Front pedal 33b Rear pedal 33c Engagement cut 34 Support shaft 35 Switching ring 35a Outer projection piece 35b Inner projection piece 36 Engagement shaft 37 Sliding contact Member 37a Pressing protrusion 38 Mounting plate 39 Pressing spring 40 Ratchet claw 51 Crankshaft 5 Crank arm 53 crankcase 53a boss 53b stopper 54 frame 55 chain 56 pedal

Claims (8)

  A plurality of front rotating bodies corresponding to the number of shift stages are arranged side by side around a crank rotating body fixed to a crankshaft that rotates by the pedaling force of the pedal, and each front rotating body is arranged by a sub-shaft provided behind the crankshaft. A rear rotating body interlocking with a predetermined speed ratio is supported so as to be integrally rotatable, a ratchet claw corresponding to each front rotating body is provided on the crank rotating body, and a ratchet tooth engaged with the ratchet claw is provided in each front rotating body. A crankshaft is formed by switching the front rotating body that transmits the driving force to the rear rotating body by engaging and disengaging the ratchet claw with the ratchet teeth in accordance with the operation of the switching member that is formed on the circumferential side and that contacts and separates from the ratchet claw. A bicycle transmission that changes the speed ratio of the rotation transmitted from the motor to the rear wheel drive sprocket.   2. The bicycle transmission according to claim 1, wherein the front rotating body and the rear rotating body are gears and meshed with each other.   The bicycle transmission according to claim 1, wherein the front rotating body and the rear rotating body are sprockets, and a chain is spanned between them.   2. The bicycle transmission according to claim 1, wherein the front rotating body and the rear rotating body are toothed pulleys, and a toothed belt is stretched over the pulleys.   The bicycle transmission according to claim 1, wherein an internal gear is provided in any of the front rotating bodies, and any of the rear rotating bodies that are gears is engaged with the internal gears, and the other front rotating bodies that are gears A bicycle transmission characterized in that a rear rotating body is meshed with an intermediate gear.   2. The bicycle transmission according to claim 1, wherein one of the front rotators is provided with an internal gear, and any one of the rear rotators as gears is engaged with the internal gear to form a toothed pulley. A bicycle transmission comprising a toothed belt placed between a body and a rear rotating body.   7. The bicycle transmission according to claim 1, wherein only the ratchet pawl for transmitting the driving force meshes with the ratchet teeth, and the meshing between the other ratchet pawls and the ratchet teeth is released. A bicycle transmission characterized by the above.   The bicycle transmission according to any one of claims 1 to 7, wherein a shifting operation is performed by rotating a switching member when a switching pedal provided on a crank arm is depressed. Transmission device.

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