JP2016055833A - bicycle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a bicycle which is compact, which allows a user to easily carry, and easily ride on, and which allows the user to smoothly travel.SOLUTION: A bicycle 1 comprises: a head tube 21; a front fork 22; a crank shaft 23; a pair of pedals 25; a front wheel 26; a crank gear 24; a hub gear 27; a power transmission mechanism 3; a rear frame 41; a saddle part 42; a pair of rear wheels 43; a handle 51; a brake system 52; and a rear frame rotary mechanism 6. The front wheel 26 has a hub 261 rotatably supported to an outer periphery of the crank shaft 23 coaxially to the crank shaft 23. The rear frame rotary mechanism 6 is configured so that, the rear frame 41 can rotate with a connection part 60 as a fulcrum and the rear frame 41 can be fixed to the rear frame rotary mechanism. The power transmission mechanism 3 is configured to accelerate freely, so that rotation speed of the hub gear 27 becomes larger than rotation speed of the crank gear 24.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a bicycle.

  Conventionally, a two-wheeled bicycle having one front wheel and one rear wheel is known. In a two-wheeled bicycle, a metal roller chain and a belt are usually wound around the outer periphery of a crank gear attached to a crankshaft and a rear wheel gear attached to a rear wheel shaft. The two-wheeled bicycle moves forward by transmitting the pedaling force from the roller chain or belt to the rear wheel. Among the two-wheeled bicycles of this type, there is a foldable two-wheeled bicycle in which the main body frame is configured to be foldable in a horizontal fold as a relatively small size.

  A tricycle having one front wheel and two rear wheels is also known. There are many tricycles on the market for toys. This type of tricycle usually does not have a complicated power transmission mechanism, and moves forward by the force applied to the pedal being directly transmitted to the front wheels.

  In addition, there exists patent document 1 as technical literature preceding this application. Patent Document 1 discloses a two-wheeled or three-wheeled vehicle having a drive shaft having a primary shaft and a secondary shaft provided on the primary shaft. In this document, the primary shaft and the secondary shaft are connected to each other by a gear transmission so as to be driven.

JP-T-2001-527001

  However, the prior art has the following problems. That is, a general folding two-wheeled bicycle takes time and effort for complicated folding and subsequent assembly. For this reason, there are people who feel hesitant about carrying the above-mentioned two-wheeled bicycle by bringing it into public transportation such as a train or a bus or storing it in a luggage compartment of a private car. Moreover, the speed of the two-wheeled bicycle when driving is too high for an elderly person whose physical function has deteriorated.

  On the other hand, since many general tricycles are for toys, elderly people have resistance to ride. Further, the tricycle has a driving speed that is too slow because the pedaling force is directly transmitted to the front wheels. For this reason, the tricycle cannot be a moving means for moving a relatively long distance such as a city ride.

  The present invention has been made in view of the above background, and aims to provide a bicycle that is small and can be carried and carried easily and can be driven slowly.

One aspect of the present invention is a tubular head tube;
A front hawk that includes a column and a pair of fork legs, and through which the column penetrates the head tube;
A crankshaft rotatably supported at the tip of the pair of hawk legs;
A pair of pedals attached to both ends of the crankshaft via a crank;
A front wheel provided with a hub rotatably supported on the outer periphery of the crankshaft coaxially with the crankshaft;
A crank gear fixed to the crankshaft;
A hub gear having fewer teeth than the crank gear and fixed to the hub;
A power transmission mechanism for transmitting the rotational force of the crank gear to the hub gear;
A rear frame having a substantially arc-shaped curve;
A saddle portion disposed on the rear frame;
A pair of rear wheels that are rotatably attached to the rear end of the rear frame and have a smaller diameter than the front wheels;
A handle attached to the column or the rear frame via a stem;
A brake system for braking the front wheel and the rear wheel;
From the driving state in which the outer peripheral portion of the head tube and the front end portion of the rear frame are connected, the front wheels projecting forward to the stowed state in which the front wheels are disposed below the rear frame, and From the stowed state to the driving state, the rear frame is configured to be rotatable with the connecting portion as a fulcrum, and the rear frame is configured to be fixed in the driving state and the stowed state. Mechanism,
There is a bicycle characterized by having.

  The bicycle has a front wheel provided with a hub that is rotatably supported coaxially with the crankshaft on the outer periphery of the crankshaft. That is, in the bicycle, the front wheel shaft is constituted by the crankshaft and the hub. Therefore, compared to a general two-wheel bicycle, the above-mentioned bicycle can shorten the distance between the center portion of the front wheel and the center portion of the rear wheel, and can be reduced in size without complicated folding. Can do.

  The bicycle has the rear frame rotation mechanism. Therefore, the bicycle is in a storage state in which the front wheels are arranged below the rear frame, and the rear frame is fixed in this storage state, so that the bicycle can be reduced in size when not traveling. Therefore, the owner of the bicycle can easily carry the bicycle by bringing it into public transportation such as a train or bus, or by storing it in a luggage compartment of a private car. Further, the bicycle can be in a driving state in which the front wheels are arranged to protrude forward, and the rear frame can be fixed in this driving state. Therefore, the owner of the bicycle can change the bicycle from the housed state to the driving state relatively easily at the destination, and can get on the bicycle immediately.

  In addition, since the bicycle has the power transmission mechanism, the speed is increased so that the rotation speed of the hub gear is larger than the rotation speed of the crank gear. Therefore, the above-mentioned bicycle can speed up more than a tricycle that has a pedaling force of 1: 1 and is transmitted directly to the front wheels, and can suppress the speed more than a general two-wheel bicycle. Therefore, the bicycle can be driven slowly.

  As described above, according to the present invention, it is possible to provide a bicycle that is small and can be carried and carried easily and can be driven comfortably.

It is a perspective view of the bicycle of Example 1 made into the driving state. It is explanatory drawing for demonstrating the detail of the power transmission mechanism in the bicycle of Example 1. FIG. In the bicycle of Example 1, it is explanatory drawing for demonstrating the detail of the 1st roller chain of a power transmission mechanism, and a 2nd roller chain. In the bicycle of Example 1, it is explanatory drawing for demonstrating the detail of the 1st intermediate | middle gear and 2nd intermediate | middle gear of a power transmission mechanism. In the bicycle of Example 1, it is explanatory drawing for demonstrating the detail of the angle adjustment mechanism of a handle | steering-wheel. In the bicycle of Example 1, it is the figure which expanded and showed the angle adjustment mechanism of the handle | steering-wheel. It is a perspective view of the bicycle of Example 1 made into the 2nd handle folding form by which the handle was folded back. In the bicycle of Example 1, it is explanatory drawing for demonstrating the detail of a rear-frame rotation mechanism. In the bicycle of Example 1, it is the figure which expanded and showed the rear-frame rotation mechanism. It is a perspective view of the bicycle of Example 2 made into the driving | running state. It is a perspective view of the bicycle of Example 2 made into the 2nd handle folding form by which the handle was folded back. It is explanatory drawing for demonstrating the detail of the power transmission mechanism in the bicycle of Example 2. FIG. It is a perspective view of the bicycle of Example 3 made into the driving | running state. It is a perspective view of the bicycle of Example 3 made into the 2nd handle folding form by which the handle was folded back. It is a perspective view of the bicycle of Example 3 made into the 1st handle folding form by which the handle was folded forward. It is explanatory drawing for demonstrating the steering system in the bicycle of Example 3. FIG. FIG. 10 is another explanatory diagram for explaining the steering system in the bicycle according to the third embodiment.

  The bicycle can have an angle adjustment mechanism on the stem that can adjust the angle of the handle in the front-rear direction in multiple stages.

  In this case, it is possible to arrange the handle at a position suitable for driving according to the physique and preferences of the driver who drives the bicycle.

  At this time, the bicycle has a first handle folded form in which the handle is folded forward and / or a second handle in which the handle is folded backward by adjusting the angle of the handle by the angle adjusting mechanism. It is preferable that it can be transformed into a folded form.

  In this case, by deforming into the first handle folded form and / or the second handle folded form, the handle does not protrude upward, and the bicycle can be further miniaturized. Moreover, since it can carry by pushing and pulling the folded handle | steering-wheel part, portability is also improved.

  The bicycle is disposed in front of the front wheels, and can have a pair of auxiliary front wheels having a smaller diameter than the front wheels.

  In this case, the carryability of the bicycle can be improved by the auxiliary front wheel. Specifically, when the bicycle has auxiliary front wheels, the bicycle can be configured as follows, for example.

  The bicycle has a front frame that is curved in a substantially arc shape, and the rear end of the front frame is fixed to the above-mentioned connecting portion, and the auxiliary front wheel is rotatable at the front end of the front frame. It is attached and can be configured such that the auxiliary front wheels are grounded when in the driving state and the storage state.

  In this case, since the auxiliary front wheel attached to the front end portion of the front frame is grounded in the driving state, the stability of the bicycle during driving is improved. Further, since the auxiliary front wheel is grounded in the storage state, the stability of the bicycle during carrying is improved, and the carrying performance of the bicycle by pushing and pulling is improved.

  The bicycle is fixed to each of the pair of hawk legs and has a pair of arm portions protruding forward, and an auxiliary front wheel is rotatably attached to the front end portion of the arm portion. It is also possible to configure so that the auxiliary front wheel is not grounded when in the state, and the auxiliary front wheel is grounded when in the stored state.

  In this case, since the auxiliary front wheel attached to the front end portion of the arm portion is grounded in the storage state, the stability of the bicycle during carrying is improved, and the carryability of the bicycle by pushing and pulling is improved.

  When the bicycle has auxiliary front wheels, the bicycle can be configured so that the front wheels do not come into contact with the ground when the bicycle is stored.

  In this case, since the rear wheel and the auxiliary front wheel are in contact with each other, the turning performance is improved and the carrying performance of the bicycle by pushing and pulling is further improved.

  When the bicycle has auxiliary front wheels, the bicycle has a pair of steering levers for steering the rear wheels and / or auxiliary front wheels, and a pair of steering wheels connected to the steering levers and extending to the rear wheels and / or auxiliary front wheels. Steering configured to include a cable and a direction switching mechanism that is connected to the steering cable and applies a steering angle to the rear wheel and / or the auxiliary front wheel by using a tensile force generated in the steering cable by operation of the steering lever. You can have a system.

  In this case, the bicycle driver changes the traveling direction of the bicycle and turns the bicycle not only by operating the steering wheel but also by steering the rear wheel and / or the auxiliary front wheel by operating the steering lever of the steering system. be able to. Therefore, in this case, the turning performance of the bicycle can be improved.

  In the above bicycle, the power transmission mechanism may be capable of increasing the speed so that the rotation speed of the hub gear is larger than the rotation speed of the crank gear.

  In the bicycle, specifically, the power transmission mechanism includes, for example, an intermediate shaft that is rotatably supported on one of the fork legs, and a first intermediate gear that is positioned above the crank gear and is fixed to the intermediate shaft. The first roller chain wound around the outer periphery of the first intermediate gear, the second intermediate gear positioned above the hub gear and fixed to the intermediate shaft, and the second roller chain wound around the outer periphery of the second intermediate gear Each tooth tip of the first intermediate gear and the second intermediate gear is in contact with each roller included in the first roller chain and the second roller chain, and each tooth of the crank gear and the hub gear is It can be set as the structure which enters in the clearance gap between each roller of a 1st roller chain and a 2nd roller chain, and has each meshed | engaged.

  In this case, since the distance between the crankshaft and the intermediate shaft can be shortened, the power transmission mechanism can be reduced in size. Therefore, in this case, the degree of freedom when selecting the size of the front wheel is improved.

  Specifically, the power transmission mechanism includes, for example, an intermediate shaft that is rotatably supported on one of the fork legs, a first intermediate gear that is positioned above the crank gear and is fixed to the intermediate shaft, 1 An outer roller chain wound around the outer periphery of the intermediate gear and the crank gear, a second intermediate gear positioned above the hub gear and fixed to the intermediate shaft, and wound around the outer periphery of the second intermediate gear and the hub gear It is also possible to adopt a configuration including an inner roller chain.

  In this case, it is possible to configure a power transmission mechanism that can transmit to the hub gear by increasing the rotational speed of the crank gear with a relatively simple structure. Therefore, in this case, a bicycle excellent in manufacturability of the power transmission mechanism can be obtained. The power transmission mechanism described above may be covered with a cover member or the like.

  In the bicycle described above, the rear frame includes a right rear frame portion disposed on the right side, and a left rear frame portion that is disposed apart from the right rear frame portion and that extends along the right rear frame portion. Is preferred.

  In this case, since the driver's weight can be received at the right rear frame portion and the left rear frame portion, a bicycle having excellent strength can be obtained. In addition, the left / right balance of the bicycle is improved.

  In addition, each structure mentioned above can be arbitrarily combined as needed, in order to acquire each effect etc. which were mentioned above.

  Hereinafter, the bicycle according to the embodiment will be described with reference to the drawings. In each figure, the spokes of the front wheels and the rear wheels are omitted for convenience.

(Example 1)
The bicycle according to the first embodiment will be described with reference to FIGS. As shown in FIGS. 1 to 9, the bicycle 1 of this example includes a head tube 21, a front fork 22, a crankshaft 23, a pair of pedals 25, a front wheel 26, a crank gear 24, and a hub gear 27. And a power transmission mechanism 3, a rear frame 41, a saddle portion 42, a pair of rear wheels 43, a handle 51, a brake system 52, and a rear frame rotation mechanism 6. The details will be described below.

  The head tube 21 is formed in a tubular shape.

  The front fork 22 includes a column 221 and a pair of fork legs 222. The column 221 penetrates the inside of the head tube 21.

  The crankshaft 23 is rotatably supported at the tip portions of the pair of fork legs 222. Specifically, in this example, crank bearings 223 are respectively provided at the distal ends of the pair of fork legs 222, and the crankshaft 23 is rotatably supported by each crank bearing 223.

  The pair of pedals 25 are attached to both ends of the crankshaft 23 via cranks 231. In this example, the pedal 25 has a known folding mechanism (not shown) and is configured to be foldable by the folding mechanism.

  The front wheel 26 includes a hub 261 that is rotatably supported coaxially with the crankshaft 23 on the outer periphery of the crankshaft 23. In this example, the hub 261 has a ratchet function.

  The crank gear 24 is fixed to the crankshaft 23. Specifically, in this example, the crank gear 24 is disposed outside one hawk leg 222 (here, the right hawk leg 222). Note that the crank gear 24 may be disposed inside the one fork leg 222.

  The hub gear 27 is fixed to the hub 261. In this example, the hub gear 27 is disposed inside one hawk leg 222 (here, the right hawk leg 222). The hub gear 27 has fewer teeth than the crank gear 24.

  The power transmission mechanism 3 has a role of transmitting the rotational force of the crank gear 24 to the hub gear 27. By having the power transmission mechanism 3, the bicycle 1 is accelerated so that the rotation speed of the hub gear 27 is larger than the rotation speed of the crank gear 24. In this example, specifically, as shown in FIG. 2, the power transmission mechanism 3 includes an intermediate shaft 31, a first intermediate gear 32, a first roller chain 34, a second intermediate gear 33, 2 roller chains 35.

  In the power transmission mechanism 3, the intermediate shaft 31 is rotatably supported by one of the hawk legs 222 (here, the right hawk leg 222). Specifically, an intermediate bearing 311 is provided in the middle of the pair of fork legs 222, and the intermediate shaft 31 is rotatably supported by the intermediate bearing 311. The first intermediate gear 32 is positioned above the crank gear 24 and is fixed to the intermediate shaft 31. In this example, an example in which the crank gear 24 is disposed outside the hawk leg 222 is shown, and therefore the first intermediate gear 32 is also disposed outside the hawk leg 222. Although not shown, when the crank gear 24 is disposed inside the hawk leg 222, the first intermediate gear 32 is also disposed inside the hawk leg 222. The second intermediate gear 33 is positioned above the hub gear 27 and is fixed to the intermediate shaft 31. In the present example, since the hub gear 27 is disposed inside the hawk leg 222, the second intermediate gear 33 is also disposed inside the hawk leg 222. In this example, the number of teeth of each gear 24, 32, 33, 27 is the number of teeth of the first intermediate gear 32 <the number of teeth of the hub gear 27 <the number of teeth of the second intermediate gear 33 <the number of teeth of the crank gear 24. It is configured to satisfy the relationship. The number of teeth of each of the gears 24, 32, 33, and 27 is not particularly limited and can be appropriately changed as long as the rotational speed of the crank gear 24 can be increased and transmitted to the hub gear 27.

  In the power transmission mechanism 3, the first roller chain 34 is wound around the outer periphery of the first intermediate gear 32. The second roller chain 35 is wound around the outer periphery of the second intermediate gear 33. Although the first roller chain 34 and the second roller chain 35 have different chain lengths, they basically have the same configuration. In this example, specifically, as shown in FIG. 3, each of the first roller chain 34 and the second roller chain 35 has a structure in which inner links 36 and outer links 37 are alternately connected. ing. The inner link 36 is provided so as to be rotatable about a pair of inner plates 362 each having two bush holes 361, a pair of bushes (not shown) connecting the inner plates 362, and the bushes as axes. A pair of rollers 363. The outer link 37 includes a pair of outer plates 371 and a pair of pins 372 that couple the outer plates 371 together. The pin of the outer link 37 is inserted into the bush hole 361 of the inner link 36 to connect the outer link 37 and the inner link 36.

  In this example, in each of the first roller chain 34 and the second roller chain 35, the pair of outer plates 371 in at least one or more outer links 37 is located inward of the first intermediate gear 32 and the second intermediate gear 33. Protrusively formed. Therefore, the first intermediate gear 32 and the second intermediate gear 33 are sandwiched by a pair of protruding outer plates 371a, and the first roller chain 34 and the second roller chain 35 are configured not to easily come off. The protruding outer plate 371 a has a pin hole 373 formed in the protruding portion, and is fixed to the gears 32 and 33 by a pin 374 that passes through the pin hole 373. In this example, an example having bushes as the first roller chain 34 and the second roller chain 35 is shown. The first roller chain 34 and the second roller chain 35 may have a known bushless structure.

  In the power transmission mechanism 3, the tooth tips of the first intermediate gear 32 and the second intermediate gear 33 are in contact with the rollers 363 included in the first roller chain 34 and the second roller chain 35, respectively. In this example, specifically, as shown in FIG. 4, the tooth tips of the first intermediate gear 32 and the second intermediate gear 33 are arcuate so as to be able to contact along the outer periphery of the roller 363. Is formed. In the power transmission mechanism 3, the teeth 241 and 271 of the crank gear 24 and the hub gear 27 enter the gap 38 between the rollers 363 of the first roller chain 34 and the second roller chain 35 and mesh with each other.

  The rear frame 41 has a shape curved in a substantially arc shape. Specifically, in this example, the rear frame 41 includes a right rear frame portion 412 disposed on the right side, and a left rear frame portion disposed away from the right rear frame portion 412 and along the right rear frame portion 412. 413. The right rear frame portion 412 and the left rear frame portion 413 are connected and integrated at the front end portions of the frame portions 412 and 413. Also, the right rear frame portion 412 and the left rear frame portion 413 are connected by a rear frame connecting plate 414 provided in the middle of each frame portion 412, 413. Further, the right rear frame portion 412 and the left rear frame portion 413 are connected by a rear frame connecting pipe 415 provided in the middle of each frame portion 412, 413 on the rear end side of the rear frame connecting plate 414. Yes.

  The saddle portion 42 is disposed on the rear frame 41. In this example, specifically, the saddle portion 42 is attached to the rear frame 41. The saddle portion 42 includes a saddle 421 and a saddle post 422 extending from below the saddle 421. The saddle post 422 is mounted on the rear frame 41 via a saddle mounting bracket 423. The saddle mounting bracket 423 is configured so that the saddle post 422 can be fastened and fixed. In addition, if the saddle part 42 is arrange | positioned on the rear frame 41, it may be attached to the column 221 of the front fork 22 which penetrated the head tube 21 by another saddle attachment bracket (not shown), for example. .

  The pair of rear wheels 43 are rotatably attached to the rear end portion of the rear frame 41. Specifically, in this example, a rear wheel connecting pipe 431 is fixed to the rear end portion of the rear frame 41. Rear wheel bearings (not shown) are provided at both ends of the rear wheel connecting pipe 431, and the rear wheel shaft 432 is rotatably supported by the respective rear wheel bearings. Each rear wheel 43 is attached to each end of the rear wheel shaft 432. Each rear wheel 43 is formed to have a smaller diameter than the front wheel 26. In this example, springs 44 are respectively provided in the right rear frame portion 412 and the left rear frame portion 413 between the rear wheel connecting tube 431 and the rear frame connecting tube 415. The spring 44 has an effect of improving cushioning properties. The spring 44 improves the balance so that the pair of rear wheels 43 are in contact with the ground against the left and right inclination caused by the operation of the handle 51, and improves the operability of the handle 51 by the restoring force. There is an effect of improving. The pair of rear wheels 43 may be rotatably attached to the rear end of the rear frame 41 by a rear fork (not shown) provided for each rear wheel 43.

  The handle 51 is attached to the column 221 via a stem 511. In this example, specifically, a stem 511 is attached to the upper end portion of the column 221 that penetrates the inside of the head tube 21, and the clamp portion 512 of the handle 51 is attached to the stem 511. In this example, as the handle 51, an up handle in which the grip portion 513 is disposed higher than the clamp portion 512 is used.

  The bicycle 1 of this example has an angle adjustment mechanism 53 that can adjust the angle of the handle 51 in multiple stages in the front-rear direction on the stem 511. The bicycle 1 of the present example has a first handle folding form (not shown) in which the handle 51 is folded forward by adjusting the angle of the handle 51 by the angle adjusting mechanism 53 and / or shown in FIG. As shown in the figure, the second handle is folded into a second folded form in which the handle is folded rearward. In addition, the bicycle 1 can be changed from the traveling form in which the handle 51 is raised to the first handle folded form, or from the running form in which the handle 51 is raised to the second handle folded form. Furthermore, the first handle folding configuration can be changed from the first handle folding configuration to the second handle folding configuration, and the second handle folding configuration can be changed to the first handle folding configuration.

  In this example, specifically, the angle adjustment mechanism 53 includes a plate-like body 531, a stem attachment portion 532, and a handle fixing member 533 as shown in FIGS. 5 and 6. The plate-like body 531 is fixed to the periphery of the stem mounting portion 532 in the handle 51, and a plurality of positioning groove portions 531a are formed on the outer peripheral edge. In this example, the plate-like body 531 has a disc shape, but may have a semicircular shape or the like. The stem attachment portion 532 is fixed to the stem 511. The handle fixing portion 533 is configured to be fixed in a state where the base end side is rotatably attached to the stem attachment portion 532 and is engaged with the groove portion 531a of the plate-like body 531 by a turning operation. More specifically, the handle fixing member 533 includes a bolt portion 533a whose proximal end is rotatably attached to the stem attachment portion 532 and engaged with the groove portion 531a of the plate-like body 531 by the turning operation, and the bolt portion. It has the nut part 533b provided in the front-end | tip part of 533a, and the rotation lever part 533c which can tighten or loosen the nut part 533b by rotation.

  According to the angle adjustment mechanism 53, the rotating lever portion 533 c in the handle fixing member 533 is operated, and the bolt portion 533 a is engaged with the groove portion 531 a of the plate-like body 531. By tightening 533b, the handle 51 is fixed at a predetermined angle. On the other hand, when the rotation lever portion 533c of the handle fixing member 533 is operated and the nut portion 533b is loosened by the rotation lever portion 533c, the bolt portion 533a can be rotated upward, and the angle of the handle 51 can be adjusted in the front-rear direction. It becomes a state.

  The brake system 52 is for braking the front wheel 26 and the rear wheel 43. Specifically, the brake system 52 includes a front wheel brake (not shown) that brakes the front wheel 26, a rear wheel brake 521 that brakes the rear wheel 43, and a front wheel brake that is provided on the handle 51 and operates the front wheel brake. A lever 522a (in this example, the right side of the handle 51) and a rear wheel brake lever 522b (in this example, the left side of the handle 51) provided on the handle 51 for operating the rear wheel brake 521 are configured. . In each figure, a connection cable for connecting the front wheel brake lever 522a and the front wheel brake, a connection cable for connecting the rear wheel brake lever 522b and the rear wheel brake 521, and the like are omitted. As the brake system 52, a known configuration of a two-wheeled bicycle or the like can be appropriately adopted. In this example, the front wheel brake is a caliper brake system. The rear wheel brake 521 is a disc brake system.

  The rear frame rotation mechanism 6 connects the outer peripheral portion of the head tube 21 and the front end portion of the rear frame 41. The rear frame rotating mechanism 6 has a housing in which the front wheel 26 is disposed below the rear frame 41 as shown in FIG. 7 from the driving state in which the front wheel 26 projects forward as shown in FIG. The rear frame 41 is configured to be rotatable about the connecting portion 60 from the storage state to the operation state. Further, the rear frame rotating mechanism 6 is configured such that the rear frame 41 can be fixed in an operating state and a stored state.

  In this example, specifically, the rear frame rotation mechanism 6 includes a pair of rear frame fixing plates 61, a connecting bar 62, a head tube fixing plate 63, and a rear frame fixing member 64. The pair of rear frame fixing plates 61 are fixed below the front end of the rear frame 41. Specifically, one of the rear frame fixing plates 61 is fixed below the front end portion of the right rear frame portion 412. The other of the rear frame fixing plate 61 is fixed below the front end portion of the left rear frame portion 413. The connecting bar 62 is fixed to the outer peripheral portion of the head tube 21 at the central portion. The head tube fixing plate 63 includes a pair of side plates 631 fixed to both ends of the connecting bar 62 and a bottom plate 632 that connects between the side plates 631 and through which the head tube 21 penetrates at the center portion. I have. The rear frame fixing member 64 is attached between the pair of side surface plates 631. More specifically, the rear frame fixing member 64 includes a bolt part 641 that passes between the pair of side plates 631, a nut part 642 provided at one end of the bolt part 641, and a nut part 642 that is tightened by rotation. A rotating lever portion 643 that can be inserted or loosened, and a fixing nut portion 644 provided at the other end of the bolt portion 641 are provided.

  In the rear frame rotation mechanism 6, an insertion hole 611 is formed in each rear frame fixing plate 61. The left end of the connecting bar 63 is inserted into the insertion hole 611 of the left rear frame fixing plate 61, and the right end of the connecting bar 62 is inserted into the insertion hole 611 of the right rear frame fixing plate 61. Both ends of the connecting bar 62 inserted and supported by the respective insertion holes 611 are kept from being pulled out by the nuts 621 and the nut caps 623. In addition, each rear frame fixing plate 61 is provided with a substantially arc-shaped elongated hole 612 having both ends formed in a round hole shape. Each rear frame fixing plate 61 is disposed on the outer side of each side plate 631 in the head tube fixing plate 63, and the bolt portion 641 of the rear frame fixing member 64 passes through each long hole 612. That is, the right rear frame fixing plate 61 through which the bolt portion 641 passes is disposed between the fixing nut portion 644 of the rear frame fixing member 64 and the right side plate 631. Similarly, the left rear frame fixing plate 61 through which the bolt portion 641 passes is disposed between the nut portion 642 of the rear frame fixing member 64 and the left side plate 631.

  According to the rear frame rotation mechanism 6, when the rotation lever portion 643 of the rear frame fixing member 64 is operated and the nut portion 642 is loosened by the rotation lever portion 643, the connection bar 62 is used as the rotation axis. The rear frame 41 can be rotated so as to approach the rear portion of the front wheel 26. Conversely, the rear frame 41 can be rotated away from the rear portion of the front wheel 26. Further, when the bolt portion 641 of the rear frame fixing member 64 is positioned in the round hole below the elongated hole 612, the rotation lever portion 643 of the rear frame fixing member 64 is operated, and the nut portion 643 is tightened by the rotation lever portion 643. As a result, the front frame 26 is in a driving state in which the front wheel 26 protrudes forward, and the rear frame 41 is fixed. On the contrary, when the bolt part 641 of the rear frame fixing member 64 is positioned in the round hole above the elongated hole 612, the rotation lever part 643 in the rear frame fixing member 64 is operated, and the nut part 642 is moved by the rotation lever part 643. By being tightened, the front wheel 26 is placed in a storage state disposed below the rear frame 41, and the rear frame 41 is fixed.

  Next, the effect of the bicycle of this example will be described.

  The bicycle 1 of the present example has a front wheel 26 provided with a hub 261 that is rotatably supported coaxially with the crankshaft 23 on the outer periphery of the crankshaft 23. That is, in the bicycle 1 of this example, the front wheel shaft is constituted by the crankshaft 23 and the hub 261. Therefore, the bicycle 1 of this example can shorten the distance between the center portion of the front wheel 26 and the center portion of the rear wheel 43 as compared with a general two-wheel bicycle, and without complicated folding, Miniaturization can be achieved.

  Further, the bicycle 1 of this example has a rear frame rotation mechanism 6. For this reason, the bicycle 1 of this example is in the storage state in which the front wheels 26 are disposed below the rear frame 41, and the rear frame 41 is fixed in this storage state, thereby reducing the size when the vehicle is not running. You can also. Therefore, the owner of the bicycle 1 of the present example can easily carry the bicycle 1 of the present example by bringing it into public transportation such as a train or a bus or storing it in the luggage compartment of a private car. Moreover, the bicycle 1 of this example is in a driving state in which the front wheels 26 are arranged to protrude forward, and the rear frame 41 can be fixed in this driving state. Therefore, the owner of the bicycle 1 according to the present example can change the bicycle 1 according to the present example from the housed state to the driving state relatively easily at the carry-on destination and can get on immediately.

  In addition, since the bicycle 1 of this example has the power transmission mechanism 3 described above, the speed is increased so that the rotational speed of the hub gear 27 is larger than the rotational speed of the crank gear 24. Therefore, the bicycle 1 of the present example can produce a speed higher than that of a tricycle that has a 1: 1 pedaling force and is directly transmitted to the front wheels, and can suppress the speed more than a general two-wheel bicycle. it can. Therefore, the bicycle 1 of this example can be driven comfortably. Moreover, since the power transmission mechanism 3 described above can shorten the distance between the crankshaft 23 and the intermediate shaft 31, the power transmission mechanism 3 can be reduced in size. Therefore, the bicycle 1 of the present example improves the degree of freedom when selecting the size of the front wheel 26.

  In addition, the bicycle 1 of the present example has an angle adjustment mechanism 53 that can adjust the angle of the handle 51 in multiple stages in the front-rear direction on the stem 511. Therefore, according to the physique and preferences of the driver, The handle 51 can be disposed at a position suitable for driving. In addition, the bicycle 1 of this example can be deformed into the first handle folded form and / or the second handle folded form by adjusting the angle of the handle 51 by the angle adjusting mechanism 53, and the handle Since it does not protrude upward, further downsizing can be achieved. Moreover, since the bicycle 1 of this example can be carried by pushing and pulling the folded handle 51, the carrying performance is also improved.

  Furthermore, in the bicycle 1 of this example, the rear frame 41 includes a right rear frame portion 412 and a left rear frame portion 413. For this reason, the bicycle 1 of this example can receive the weight of the driver at the right rear frame portion 412 and the left rear frame portion 413, and is excellent in strength. Moreover, the bicycle 1 of this example also improves the left and right balance.

(Example 2)
A bicycle according to the second embodiment will be described with reference to FIGS. The bicycle 1 of the second embodiment is different from the bicycle of the first embodiment in that it has a pair of auxiliary front wheels. Further, the bicycle 1 of the second embodiment is different from the bicycle 1 of the first embodiment in the power transmission mechanism 3. Other configurations are the same as those of the first embodiment. Hereinafter, a different part from the bicycle 1 of Example 1 is demonstrated.

  In the bicycle 1 of this example, the pair of auxiliary front wheels 7 are disposed in front of the front wheels 26 and are formed with a diameter smaller than that of the front wheels 26.

  Specifically, the bicycle 1 of this example includes a pair of arm portions 72 that are fixed to each of the pair of hawk legs 222 and project forward. The pair of arm portions 72 are connected by a reinforcing arm 721 on the front side. The auxiliary front wheels 7 are rotatably attached to the front end portions of the arm portions 72, respectively. The auxiliary front wheel 7 in this example is specifically composed of a rotatable caster.

  As shown in FIG. 10, the bicycle 1 is configured such that the auxiliary front wheel 7 does not come into contact with the ground when the rear frame rotation mechanism 6 is operated to be in a driving state. On the other hand, as shown in FIG. 11, the bicycle 1 is configured such that the auxiliary front wheel 7 is grounded when the rear frame rotating mechanism 6 is operated to be in the retracted state. Furthermore, the bicycle 1 is configured so that the front wheel 26 does not come into contact with the ground when the bicycle 1 is in the stored state.

  In the bicycle 1 of this example, the power transmission mechanism 3 includes an intermediate shaft 31, a first intermediate gear 32, an outer roller chain 38, a second intermediate gear 33, and an inner roller chain 39.

  In the power transmission mechanism 3, the intermediate shaft 31 is rotatably supported by one of the hawk legs 222 (here, the right hawk leg 222). Specifically, an intermediate bearing 311 is provided in the middle of the pair of fork legs 222, and the intermediate shaft 31 is rotatably supported by the intermediate bearing 311. The first intermediate gear 32 is positioned above the crank gear 24 and is fixed to the intermediate shaft 31. In this example, an example in which the crank gear 24 is disposed outside the hawk leg 222 is shown, and therefore the first intermediate gear 32 is also disposed outside the hawk leg 222. Although not shown, when the crank gear 24 is disposed inside the hawk leg 222, the first intermediate gear 32 is also disposed inside the hawk leg 222. The second intermediate gear 33 is positioned above the hub gear 27 and is fixed to the intermediate shaft 31. In the present example, since the hub gear 27 is disposed inside the hawk leg 222, the second intermediate gear 33 is also disposed inside the hawk leg 222. In this example, the number of teeth of each gear 24, 32, 33, 27 is the number of teeth of the first intermediate gear 32 <the number of teeth of the crank gear 24, the number of teeth of the second intermediate gear 33 = the number of teeth of the crank gear 24. The number of teeth of the first intermediate gear 32 is equal to the number of teeth of the hub gear 27. The number of teeth of each of the gears 24, 32, 33, and 27 is not particularly limited and can be appropriately changed as long as the rotational speed of the crank gear 24 can be increased and transmitted to the hub gear 27.

  In the power transmission mechanism 3, the outer roller chain 38 is wound around the outer periphery of the first intermediate gear 32 and the crank gear 24. In other words, the first intermediate gear 32 and the crank gear 24 are arranged so as to be separated from each other and rotate with respect to each other via the outer roller chain 38. Similarly, the inner roller chain 39 is wound around the outer periphery of the second intermediate gear 33 and the hub gear 27. That is, the second intermediate gear 33 and the hub gear 27 are arranged to be separated from each other and rotate with each other via the inner roller chain 39. The outer roller chain 38 and the inner roller chain 39 basically have the same configuration. In this example, the outer roller chain 38 and the inner roller chain 39 are known roller chains.

  Next, the effect of the bicycle of this example will be described.

  Since the bicycle 1 of this example has the auxiliary front wheels 7, it is possible to improve portability. In particular, the bicycle 1 of the present example is configured such that the auxiliary front wheel 7 is not grounded when in the driving state, and the auxiliary front wheel 7 is grounded when in the stowed state. Therefore, in the bicycle 1 of this example, the auxiliary front wheel 7 attached to the front end portion of the arm portion 72 is grounded in the stored state, so that the stability during carrying is improved and the carrying property by pushing and pulling is improved. Furthermore, the bicycle 1 of this example is configured so that the front wheel 26 does not come into contact with the ground when the bicycle 1 is in the stored state. Therefore, the bicycle 1 of this example is in a state where the rear wheel 43 and the auxiliary front wheel 7 are in contact with the ground, so that the turning performance is improved and the carrying performance by pushing and pulling is further improved.

  Further, the power transmission mechanism 3 described above has a relatively simple structure, and can increase the rotational speed of the crank gear 24 and transmit it to the hub gear 27. The bicycle 1 of this example is excellent in the manufacturability of the power transmission mechanism 3. Other functions and effects are the same as those of the first embodiment.

(Example 3)
A bicycle according to the third embodiment will be described with reference to FIGS. The bicycle 1 according to the third embodiment is implemented in that it has a pair of auxiliary front wheels 7, the configuration of the saddle portion 42, a different mounting method, a different mounting method of the handle 51, and a steering system 8. This is different from the bicycle 1 in Example 1. Other configurations are the same as those of the first embodiment. Hereinafter, a different part from the bicycle 1 of Example 1 is demonstrated.

  In the bicycle 1 of this example, the pair of auxiliary front wheels 7 are disposed in front of the front wheels 26 and are formed with a diameter smaller than that of the front wheels 26.

  Specifically, the bicycle 1 of this example has a front frame 71 that has a curved shape on a substantially arc. A rear end portion of the front frame 71 is fixed to a connecting portion 60 between the head tube 21 and the rear frame 41. Specifically, in this example, the front frame 71 includes a right front frame portion 711 disposed on the right side, and a left front frame portion disposed away from the right front frame portion 711 and along the right front frame portion 711. 712. The right front frame part 711 and the left front frame part 712 are connected by a front frame connecting plate 713 provided in the middle part of each frame part 711, 712. The right front frame portion 711 and the left front frame portion 712 are connected by a front frame connecting pipe (not shown) provided in the middle of each frame portion 711, 712 on the front end side of the front frame connecting plate 713. May be. The rear end portion of the right front frame portion 711 is attached to the right end portion of the connection bar 62. The rear end portion of the left front frame portion 712 is attached to the left end portion of the connection bar 62. Further, above the right front frame portion 711 and the left front frame portion 712, a pair of receivers that support the right rear frame portion 412 and the left rear frame portion 413 of the rear frame 41 from below when in an operating state. A portion 715 is provided.

  The pair of auxiliary front wheels 7 are rotatably attached to the front end portion of the front frame 71, respectively. In this example, specifically, the auxiliary front wheel connecting pipe 73 is fixed to the front end portion of the front frame 71. Hawks 74 are attached to both ends of the auxiliary front wheel connecting pipe 73, respectively. Each auxiliary front wheel 7 is rotatably supported by a fork 74. In this example, springs 75 are provided on the right front frame portion 711 and the left front frame portion 712 between the auxiliary front wheel connecting pipe 73 and the front frame connecting plate 713, respectively. The spring 75 is for obtaining the same effect as the spring 44 described above.

  As shown in FIGS. 13 to 15, the bicycle 1 is configured such that the auxiliary front wheel 7 is grounded when the rear frame rotation mechanism 6 is operated to be in a driving state and a storage state. On the other hand, as shown in FIGS. 14 and 15, the bicycle 1 is configured so that the front wheel 26 does not come into contact with the ground when the bicycle 1 is in the stored state.

  The saddle portion 42 is disposed on the rear frame 41. However, in this example, the saddle portion 42 is attached to the column 221 of the front fork 22 that penetrates the head tube 21 via a saddle mounting bracket 424 that can be fixed by tightening the saddle post 422. The saddle portion 42 is configured to be rotatable in the vertical direction with the saddle mounting portion as a fulcrum.

  The handle 51 is attached to the front end portion of the rear frame 41 via a stem 511. In this example, specifically, a stem 511 is attached to a portion where the right rear frame portion 412 and the left rear frame portion 413 are connected to each other at the front end portion, and the handle 511 is attached to the stem 511. A clamp portion 512 is attached.

  The steering system 8 includes a pair of steering levers 81a and 81b, a pair of steering cables 82a and 82b, and a direction switching mechanism 83. The steering levers 81a and 81b are for steering the auxiliary front wheels 7 in this example. The steering cables 82a and 82b are connected to the steering levers 81a and 81b, respectively, and extend to the auxiliary front wheels 7. The direction switching mechanism 83 is connected to the steering cables 82a and 82b, and gives a steering angle to the auxiliary front wheels 7 by using the tensile force generated in the steering cables 82a and 82b by the operation of the steering levers 81a and 81b. It is configured to be possible.

  Specifically, in this example, the steering levers 81a and 81b are respectively attached to the front wheel brake lever 522a and the rear wheel brake lever 522b. More specifically, each of the steering levers 81a and 81b has a brake lever mounting bracket 523 for mounting the brake levers 522a and 522b on the handle 51, and a lever fixing bolt 524 and a lever fixing nut 525, respectively. It is attached together with 522a and 522b. In addition, in FIG. 16, the attachment condition of the steering lever 81b is illustrated.

  Each of the steering cables 82a and 82b has an upper steering cable 821a and 821b and a lower steering cable 822a and 822b. Each steering cable 82a, 82b extends to each auxiliary front wheel 7. However, in this example, the tension force amplifying plate 823 is swingably attached to the surface of the front frame connecting plate 713 by a fixing screw 824. The upper steering cables 821a and 821b and the lower steering cables 822a and 822b are connected via a tensile force amplifying plate 823. Specifically, the upper steering cables 821a and 821b of the steering cables 82a and 82b are fixed to the left and right sides of the fixing screw 824 in the tensile force amplifying plate 823, respectively. On the other hand, the lower steering cables 822a and 822b of the respective steering cables 82a and 82b are fixed to the tensile force amplifying plate 823 at positions outside the fixed positions of the upper steering cables 821a and 821b. Therefore, when the upper steering cables 821a and 821b are pulled by the steering levers 81a and 81b, the tensile force amplification plate 823 swings around the fixing screw 824, and the lower steering cables 822a and 822b are pulled more greatly. That is, the tensile force of the steering cables 82a and 82b is amplified by the tensile force amplification plate 823. The lower steering cables 822a and 822b of the steering cables 82a and 82b extend through the pair of sleeves 716 formed on the surface of the front frame connecting plate 713 to the auxiliary front wheels 7.

  Specifically, the direction switching mechanism 83 includes a pair of pulleys 831a and 831b, a connection cable 832, and a spring member 833. The pair of pulleys 831a and 831b are fixed to the column 741 of each fork 74, respectively. The connecting cable 832 connects the pulleys 831a and 831b. Both ends of the connecting cable 832 are disposed along part of the grooves of the pulleys 831a and 831b, and both ends are fixed to the pulleys 831a and 831b. . Both ends of the spring member 833 are fixed to the pulleys 831a and 831b. Then, the lower ends of the pair of steering cables 82a and 82b, that is, the lower ends of the lower steering cables 822a and 822b in this example are connected to the pulleys 831a and 831b to which both ends of the connecting cable 832 are fixed, respectively. Has been. A steering cable 82a extending from the right steering lever 81a disposed on the right side of the handle 51 is connected to the right pulley 831a. A steering cable 82b extending from the left steering lever 81b disposed on the left side of the handle 51 is connected to the left pulley 831b. In FIGS. 14 and 15, the steering cables 82a and 82b are omitted.

  As described above, in the bicycle 1 of this example, for example, when the right steering lever 81a is pulled, the tensile force is amplified by the tensile force amplifying plate 823, and the right pulley 831a rotates clockwise. Since one end of the connection cable 832 is fixed to the right pulley 831a, the connection cable 832 is pulled as the right pulley 831a rotates. Since the other end of the connection cable 832 is fixed to the left pulley 831b, the left pulley 831b also rotates clockwise in conjunction with the rotation of the right pulley 831a. Thus, a steering angle suitable for clockwise rotation is given to the auxiliary front wheel 7, and the bicycle 1 can be easily rotated clockwise. After turning as described above, when the right steering lever 81a is returned to the original position, both auxiliary front wheels 7 are returned to the original position, that is, a position suitable for the straight traveling direction by the tensile force of the spring member 833. It is. When the left steering lever 81b is pulled, a steering angle suitable for counterclockwise rotation is given to the auxiliary front wheel 7 in the same manner as described above.

  Next, the effect of the bicycle of this example will be described.

  Since the bicycle 1 of this example has the auxiliary front wheels 7, it is possible to improve portability. In particular, the bicycle 1 of the present example is configured such that the auxiliary front wheel 7 is grounded when in the driving state and the storage state. Therefore, since the auxiliary front wheel 7 attached to the front end portion of the front frame 71 is grounded in the driving state, the bicycle 1 of this example is improved in stability during driving. Further, in the bicycle 1 of this example, since the auxiliary front wheel 7 is grounded in the stored state, the stability during carrying is improved, and the carrying property by pushing and pulling is improved.

  Moreover, the bicycle 1 of this example has the steering system 8 described above. Therefore, the driver of the bicycle 1 of this example not only operates the handle 51 but also steers the auxiliary front wheel 7 by operating the steering levers 81a and 81b of the steering system 8, so that the traveling direction of the bicycle 1 of this example You can turn to switch. Therefore, in this case, the turning performance of the bicycle 1 of this example can be improved. Other functions and effects are the same as those of the first embodiment.

  As mentioned above, although the Example of this invention was described in detail, this invention is not limited to the said Example, A various change is possible within the range which does not impair the meaning of this invention.

  For example, in the bicycle 1 according to the third embodiment, the auxiliary front wheel 7 is configured to be rotatable like the rear wheel 43, the rear wheel 43 is configured to be rotatable like the auxiliary front wheel 7, and the rear wheel is controlled by the steering system 8. 43 may be configured to be steerable. Similarly, the rear wheel 43 in the bicycle 1 of the first embodiment and the bicycle 1 of the second embodiment is configured to be rotatable like the auxiliary front wheel 7 in the bicycle 1 of the third embodiment, and the rear wheel 43 is driven by the steering system 8. May be configured to be steerable.

  Further, for example, in the bicycle 1 of the third embodiment, an auxiliary front wheel 7 made of casters as shown in the bicycle 1 of the second embodiment may be provided at the front end portion of the front frame 71.

  Further, for example, in the bicycle 1 according to the first and second embodiments, the saddle portion 42 may be configured to be rotatable in the vertical direction with the saddle mounting portion as a fulcrum.

1 Bicycle 21 Head tube 22 Front fork 221 Column 222 Hawk foot 23 Crankshaft 231 Crank 24 Crank gear 25 Pedal 26 Front wheel 261 Hub 27 Hub gear 3 Power transmission mechanism 41 Rear frame 42 Saddle part 43 Rear wheel 51 Handle 511 Stem 52 Brake system 6 Rear frame rotation mechanism 60 connecting part

Claims (10)

A tubular head tube;
A front hawk that includes a column and a pair of fork legs, and through which the column penetrates the head tube;
A crankshaft rotatably supported at the tip of the pair of hawk legs;
A pair of pedals attached to both ends of the crankshaft via a crank;
A front wheel provided with a hub rotatably supported on the outer periphery of the crankshaft coaxially with the crankshaft;
A crank gear fixed to the crankshaft;
A hub gear having fewer teeth than the crank gear and fixed to the hub;
A power transmission mechanism for transmitting the rotational force of the crank gear to the hub gear;
A rear frame having a substantially arc-shaped curve;
A saddle portion disposed on the rear frame;
A pair of rear wheels that are rotatably attached to the rear end of the rear frame and have a smaller diameter than the front wheels;
A handle attached to the column or the rear frame via a stem;
A brake system for braking the front wheel and the rear wheel;
From the driving state in which the outer peripheral portion of the head tube and the front end portion of the rear frame are connected, the front wheels projecting forward to the stowed state in which the front wheels are disposed below the rear frame, and From the stowed state to the driving state, the rear frame is configured to be rotatable with the connecting portion as a fulcrum, and the rear frame is configured to be fixed in the driving state and the stowed state. Mechanism,
A bicycle characterized by comprising:   The bicycle according to claim 1, wherein the stem has an angle adjustment mechanism capable of adjusting the angle of the handle in a front-rear direction in multiple stages.   By adjusting the angle of the handle by the angle adjusting mechanism, the handle can be transformed into a first handle folded form in which the handle is folded forward and / or a second handle folded form in which the handle is folded backward. The bicycle according to claim 2, wherein   The bicycle according to any one of claims 1 to 3, further comprising a pair of auxiliary front wheels disposed in front of the front wheels and having a diameter smaller than that of the front wheels. It has a front frame that has a curved shape on a substantially arc,
The rear end of the front frame is fixed to the connecting portion, and the auxiliary front wheel is rotatably attached to the front end of the front frame.
The bicycle according to claim 4, wherein the auxiliary front wheel is configured to come into contact with the ground when the driving state and the storage state are established. It is fixed to each of the pair of hawk legs and has a pair of arm portions protruding forward,
The auxiliary front wheel is rotatably attached to the front end portion of the arm portion,
The bicycle according to claim 4, wherein the auxiliary front wheel is not grounded when the driving state is set, and the auxiliary front wheel is grounded when the driving state is set.   The bicycle according to any one of claims 4 to 6, wherein the bicycle is configured so that the front wheels do not come into contact with the ground when in the stowed state. A pair of steering levers for steering the rear wheels and / or the auxiliary front wheels;
A pair of steering cables connected to each of the steering levers and extending to the rear wheel and / or the auxiliary front wheel;
A direction switching mechanism that connects the steering cable and applies a steering angle to the rear wheel and / or the auxiliary front wheel by using a tensile force generated in the steering cable by operation of the steering lever;
The bicycle according to any one of claims 4 to 7, further comprising a steering system configured to include a steering wheel. The power transmission mechanism includes an intermediate shaft rotatably supported on one of the fork legs,
A first intermediate gear located above the crank gear and secured to the intermediate shaft;
A first roller chain wound around the outer periphery of the first intermediate gear;
A second intermediate gear positioned above the hub gear and secured to the intermediate shaft;
A second roller chain wound around the outer periphery of the second intermediate gear,
Each tooth tip of the first intermediate gear and the second intermediate gear is in contact with each roller included in the first roller chain and the second roller chain,
The teeth of the crank gear and the hub gear are in mesh with each other in the gaps between the rollers of the first roller chain and the second roller chain, respectively. Bicycle described in. The power transmission mechanism includes an intermediate shaft rotatably supported on one of the fork legs,
A first intermediate gear located above the crank gear and secured to the intermediate shaft;
An outer roller chain wound around the outer periphery of the first intermediate gear and the crank gear;
A second intermediate gear positioned above the hub gear and secured to the intermediate shaft;
The bicycle according to any one of claims 1 to 8, further comprising an inner roller chain wound around an outer periphery of the second intermediate gear and the hub gear.