Rotation transmission mechanism for bicycle, and bicycle

Abstract

To provide a rotation transmission mechanism for a bicycle that has a small number of components, is easy to assemble, low in cost, excellent in mass productivity, and excellent in durability and operation stability, and to provide the bicycle.SOLUTION: A rotation transmission mechanism 10 for a bicycle, which is mounted on one side in a longitudinal direction of a crankshaft 12 of the bicycle in which a first crank arm 11a is mounted on one side in the longitudinal direction and a second crank arm 11b is mounted on the other side in the longitudinal direction, includes: an internal rotation body 15 mounted on a base side of the first crank arm 11a and configured to rotate together with the crankshaft 12; an external rotation body 16 held by the internal rotation body 15 so as to be rotatable forward and backward and including a chain ring 13; and an elastic deformation body 17 configured to transmit rotation between the internal rotation body 15 and the external rotation body 16 by elastically deforming due to relative rotation of the internal rotation body 15 and the external rotation body 16.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention relates to a bicycle rotation transmission mechanism that is attached to a crankshaft (rotating shaft) of a bicycle, and a bicycle equipped with the same. [Background technology]

[0002] Vehicles such as bicycles, construction unicycles, and handcarts move by rotating their wheels while experiencing frictional resistance from the ground. Therefore, these vehicles require a large driving force (input energy) to move from a stopped (stationary) state until they start moving (when starting). Although these vehicles can rotate their wheels with a small driving force once they are moving, they also require a large driving force when accelerating and climbing slopes. Because these vehicles are propelled by the user, the repulsive force the user receives from the wheels (vehicle) increases in proportion to the driving force the user applies to the wheels (vehicle). Some of the input energy rebounds as impacts on the user's knees, ankles, waist, etc., placing a heavy burden on the user's body. This not only imposes a large load on the user's body, but also leads to inefficient use of the input energy and a decrease in propulsion force. Furthermore, when these vehicles suddenly start, accelerate, or climb hills, as well as when the load is heavy, and even when the user is heavy when riding a bicycle, the load (drag) on ​​the user's body increases, and the energy required also increases accordingly. Furthermore, in the case of bicycles, the up and down movement of the user's feet is converted into rotational movement by the crank, making it difficult to smoothly transmit the input energy to the wheel, especially at the top and bottom dead points. This increases the burden on the knees and ankles, causes torque interruptions, and reduces speed, making the bicycle prone to wobbling when riding at low speeds, resulting in reduced riding stability. To solve these problems, for example, Patent Documents 1 and 2 disclose rotation transmission mechanisms filed by the applicant of the present application. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] International Publication No. 2009 / 054161 [Patent Document 2] International Publication No. 2020 / 250460 Summary of the Invention [Problem to be solved by the invention]

[0004] The rotation transmission mechanisms of Patent Documents 1 and 2 absorb and store in their elastically deforming sections impact energy and excessive input energy generated by external loads during initial movement or riding, significantly reducing the load on the human body. Furthermore, when the input energy decreases or is about to run out, the stored energy can be extracted and used as power (rotational force). Bicycles equipped with these rotation transmission mechanisms allow users to easily travel uphill or uneven roads without increasing the burden on their bodies, making them extremely convenient. In particular, the rotation transmission mechanism of Patent Document 2 is a modified version of the rotation transmission mechanism of Patent Document 1, improving the lifespan of each component, operational stability, and rotation (power) transmission efficiency. Compared to the rotation transmission mechanism of Patent Document 1, the rotation transmission mechanism also offers superior mass productivity and durability.

[0005] However, these rotation transmission mechanisms require the relative rotation of the internal rotating member (first rotating body) and the external rotating member (second rotating body) during operation, and therefore gaps are provided at key points. Therefore, when these rotation transmission mechanisms are attached to the crankshaft (rotating shaft) of a bicycle ridden outdoors, rainwater and foreign matter such as gravel or dust can easily get in through these gaps, causing problems such as rust on parts and malfunctions due to clogging or jamming of foreign matter. Therefore, there was a need for further optimization of the shape and structure of bicycle rotation transmission mechanisms, as well as improvements in durability, ease of maintenance, and operational stability.

[0006] The present invention has been made in consideration of the above circumstances, and aims to provide a bicycle rotation transmission mechanism and a bicycle that have a small number of parts, are easy to assemble, are low cost and suitable for mass production, and are also durable and stable in operation. [Means for solving the problem]

[0007] A first aspect of the present invention that achieves the above object is a bicycle rotation transmission mechanism that is attached to one longitudinal side of a bicycle crankshaft, the bicycle crankshaft having a first crank arm attached to one longitudinal side and a second crank arm attached to the other longitudinal side, and an internal rotating body attached to a base side of the first crank arm and rotating together with the crankshaft; an external rotating body held on the internal rotating body so as to be rotatable in forward and reverse directions and equipped with a chain ring; and an elastically deformable body that elastically deforms when the internal rotating body and the external rotating body rotate relative to each other, and transmits rotation between the internal rotating body and the external rotating body, the internal rotating body has a main body portion formed with a crankshaft attachment portion to which a base side of the first crank arm is attached, and the main body portion has a plurality of arc-shaped spaces that penetrate the main body portion in the axial direction, curve concentrically around the axis of the main body portion, and accommodate the elastically deformable bodies; the external rotating body has a side plate portion arranged on one axial side of the internal rotating body, the chain ring arranged on the other axial side of the internal rotating body facing the side plate portion, an outer cylindrical portion that is continuous with the outer periphery of the side plate portion, is connected to the chain ring, and covers the outer periphery of the internal rotating body; and a protrusion that protrudes from the other axial side of the side plate portion, is inserted into the respective spaces of the main body portion of the internal rotating body, and presses the respective elastically deformable bodies when the bicycle is moved forward; the side plate portion is formed with a crankarm attachment hole into which a base side of the first crank arm attached to the crankshaft attachment portion is loosely fitted, and the chain ring is formed with a crankshaft insertion hole into which one longitudinal side of the crankshaft connected to the base side of the first crank arm is loosely fitted. When the bicycle moves forward, rotation input to the internal rotating body from the first crank arm and the second crank arm is transmitted to the chain ring of the external rotating body.

[0008] In the bicycle rotation transmission mechanism of the first invention, it is preferable that the external rotating body has a plurality of locking claws formed at intervals in the circumferential direction on the other axial side of the outer tube portion, and a plurality of locking holes formed corresponding to each of the locking claws on one axial side of the chain ring, and that each of the locking claws is engaged with each of the locking holes to fix the chain ring to the outer tube portion.

[0009] The bicycle rotation transmission mechanism according to the first aspect of the present invention preferably includes a sealant that seals the outer periphery of the contact surface between the outer cylindrical portion of the external rotating body and the chain ring.

[0010] In the bicycle rotation transmission mechanism according to the first aspect of the present invention, it is preferable to have a side plate cover material attached to the periphery of the crank arm mounting hole on one axial side of the side plate portion of the external rotating body, and a chain ring cover material attached to the periphery of the crank shaft insertion hole on the other axial side of the chain ring.

[0011] In the bicycle rotation transmission mechanism according to the first aspect of the present invention, the external rotating body preferably has fixing means for fixing the other axial side of each of the protrusions to the chain ring.

[0012] In the bicycle rotation transmission mechanism according to the first aspect of the present invention, it is preferable that each of the elastically deformable bodies is formed in a cylindrical shape having a through hole parallel to the axial direction of the crankshaft.

[0013] In the bicycle rotation transmission mechanism according to the first aspect of the present invention, each of the elastically deformable bodies may be formed by laminating a plurality of elastic members having different physical properties in a radial direction.

[0014] A bicycle according to a second aspect of the present invention, which achieves the above object, has the bicycle rotation transmission mechanism according to the first aspect of the present invention attached to one longitudinal side of the crankshaft. [Effects of the Invention]

[0015] The bicycle rotation transmission mechanism according to the first aspect of the present invention and the bicycle according to the second aspect of the present invention transmit rotational energy input from the first crank arm and the second crank arm to the external rotor via the elastically deformable body, and output it from a chain ring that constitutes a part of the external rotor for effective use as propulsion. While the internal rotor and the external rotor rotate relative to each other, the elastically deformable body elastically deforms to store a portion of the input energy, reducing the initial load. During operation, the elastically deformable body appropriately returns to its original state, converting the stored elastic energy into rotational energy for effective use, thereby reducing the input energy. Even if the input energy decreases or is about to be interrupted, the rotation can be reliably transmitted, suppressing fluctuations in output energy and stabilizing the output (rotation). Furthermore, the mechanism has a small number of parts, is thin and lightweight, is easy to assemble, can be manufactured at low cost, and is suitable for mass production.

[0016] The bicycle rotation transmission mechanism of the first invention has a plurality of locking claws formed at intervals in the circumferential direction on the other axial side of the outer tube portion of the external rotating body, and a plurality of locking holes formed on one axial side of the chain ring corresponding to each of the locking claws, and when each locking claw is engaged with each locking hole to fix the chain ring to the outer tube portion, the chain ring can be attached to the outer tube portion easily and reliably, resulting in excellent assembly workability.

[0017] In the bicycle rotation transmission mechanism of the first invention, if a sealing material is provided that seals the outer periphery of the contact surface between the outer tube portion of the external rotating body and the chain ring, the outer tube portion and the chain ring can be securely integrated, preventing rainwater, gravel, and other foreign matter from entering the interior of the external rotating body through the gap between the outer tube portion and the chain ring, preventing the occurrence of rust and malfunctions due to clogging or jamming of foreign matter, and providing excellent durability, maintainability, and operational stability.

[0018] In the bicycle rotation transmission mechanism of the first invention, when there is a side plate cover material attached to the periphery of the crank arm mounting hole on one axial side of the side plate portion of the external rotating body and a chain ring cover material attached to the periphery of the crank shaft insertion hole on the other axial side of the chain ring, rainwater, gravel, and other foreign matter are less likely to enter the interior of the external rotating body through the gap between the crank arm mounting hole and the crank arm and the gap between the crank shaft insertion hole and the crank shaft, thereby preventing the occurrence of rust and malfunctions due to clogging or jamming of foreign matter, and improving durability, maintainability, and operational stability.

[0019] In the bicycle rotation transmission mechanism of the first invention, if the external rotating body has fixing means for fixing the other axial side of each protrusion to the chain ring, the side plate portion and the chain ring can be integrated via each protrusion, so that when the rotation of the internal rotating body is transmitted to the external rotating body via each protrusion, no twisting occurs between the side plate portion and the chain ring, and the energy transmitted from the internal rotating body can be output from the chain ring reliably and without waste, resulting in excellent operational stability.

[0020] In the bicycle rotation transmission mechanism according to the first aspect of the present invention, if each elastically deformable body is formed in a cylindrical shape with a through hole parallel to the axial direction of the crankshaft, the elastically deformable body that is pressed by the protrusion of the external rotating body during relative rotation between the internal rotating body and the external rotating body is easily deformed (easily compressed), thereby reducing the burden on the bicycle user and increasing the energy stored when the elastically deformable body is compressed, which can be effectively used as propulsion force when it is restored.

[0021] In the bicycle rotation transmission mechanism of the first invention, when each elastically deformable body is formed by stacking multiple elastic members with different physical properties in the radial direction, the compressibility (energy absorption) and resilience (energy release) of the elastically deformable body as a whole can be adjusted by combining the physical properties (elasticity, hardness, etc.) and radial thickness of each elastic member, thereby increasing the utilization rate of the input energy. [Brief explanation of the drawings]

[0022] [Figure 1] 1 is a plan view of a main portion of a bicycle equipped with a bicycle rotation transmission mechanism according to one embodiment of the present invention; [Figure 2] 2 is a cross-sectional plan view of a main portion of a bicycle equipped with the bicycle rotation transmission mechanism. FIG. [Figure 3] FIG. 2 is a cross-sectional view taken along the line AA in FIG. [Figure 4] 2 is a side view of an internal rotating body of the rotation transmission mechanism for the bicycle. FIG. [Figure 5] FIG. 5 is a cross-sectional view taken along the line BB in FIG. 4. [Figure 6] 10 is a side view showing the state in which the chain ring of the external rotating body of the bicycle rotation transmission mechanism has been removed. FIG. [Figure 7] FIG. 7 is a cross-sectional view taken along the line CC in FIG. 6. [Figure 8] 4 is a side view showing a chain ring of an external rotating body of the bicycle rotation transmission mechanism. FIG. [Figure 9] 10 is a plan view showing a modified example of the chain ring of the external rotating body of the bicycle rotation transmission mechanism. FIG. DETAILED DESCRIPTION OF THE INVENTION

[0023] Next, embodiments of the present invention will be described with reference to the accompanying drawings to facilitate understanding of the present invention. 1 to 3, a bicycle rotation transmission mechanism 10 according to one embodiment of the present invention is attached to one longitudinal side of a bicycle crankshaft 12, which has a first crank arm 11a attached to one longitudinal side and a second crank arm 11b attached to the other longitudinal side, and transmits rotation input from the first crank arm 11a and the second crank arm 11b to a chain ring 13. The crankshaft 12 is rotatably held in a bearing portion (bottom bracket) 14 of the bicycle. As shown in Figures 2 and 3, the bicycle rotation transmission mechanism 10 has an internal rotating body 15 attached to the base side of the first crank arm 11a and rotating together with the crankshaft 12, an external rotating body 16 equipped with a chain ring 13 and held by the internal rotating body 15 so as to be rotatable in both forward and reverse directions, and an elastically deformable body 17 that elastically deforms as the internal rotating body 15 and the external rotating body 16 rotate relative to each other, transmitting rotation between the internal rotating body 15 and the external rotating body 16.

[0024] Here, as shown in Figures 2 to 5, the internal rotating body 15 has a main body 20 in which a crankshaft mounting portion 19 is formed, to which the base side of the first crank arm 11a is mounted, and the main body 20 is formed with a plurality (here, five) of arc-shaped space portions 21 that penetrate the main body 20 in the axial direction, curve concentrically around the axis of the main body 20, and accommodate the elastically deformable body 17. 2, 3, and 6 to 8, the external rotating body 16 has a side plate portion 22 arranged on one axial side of the internal rotating body 15, a chain ring 13 arranged opposite the side plate portion 22 on the other axial side of the internal rotating body 15, an outer tubular portion 23 connected to the outer periphery of the side plate portion 22 and connected to the chain ring 13 to cover the outer periphery of the internal rotating body 15, and protrusions 24 protruding from the other axial side of the side plate portion 22 and inserted into each space 21 of the main body portion 20 of the internal rotating body 15 to press each elastically deformable body 17 when the bicycle moves forward. Some or all of the side plate portion 22, the outer tubular portion 23, and the protrusions 24 may be formed integrally, or each portion may be formed from separate members and fixed together by means of joining (welding, welding, etc.) or screwing, etc. As shown in Figure 2, the side plate portion 22 is formed with a crank arm mounting hole 26 into which the base side of the first crank arm 11a attached to the crank shaft attachment portion 19 is loosely fitted, and the chain ring 13 is formed with a crank shaft insertion hole 27 into which one longitudinal side of the crank shaft 12 connected to the base side of the first crank arm 11a is loosely fitted.

[0025] With the above configuration, when the bicycle moves forward, the rotation input from the first crank arm 11a and the second crank arm 11b to the internal rotating body 15 can be transmitted to the chain ring 13 of the external rotating body 16. More specifically, when a cyclist rotates the first crank arm 11a and the second crank arm 11b by pedaling (not shown) attached to the tip of the first crank arm 11a and the second crank arm 11b, causing the first crank arm 11a and the second crank arm 11b to rotate in the direction of the bicycle moving forward, the crankshaft 12 connected to the first crank arm 11a and the second crank arm 11b and the internal rotating body 15 attached to the crankshaft 12 also rotate together in the direction of arrow a in Figure 3. Then, as the internal rotating body 15 and the external rotating body 16 rotate relative to each other, the elastically deformable bodies 17 housed in each space 21 of the main body 20 of the internal rotating body 15 are pressed against each protrusion 24 of the external rotating body 16 and compressed. During this time, part of the energy (rotational energy) input from the first crank arm 11a and the second crank arm 11b is accumulated in each elastically deformable body 17. Eventually, when the elastically deformable body 17 can no longer deform, the internal rotating body 15 and the external rotating body 16 rotate together in the direction of arrow a in Figure 3, and this rotation is transmitted to the rear wheel (not shown) of the bicycle via a chain (not shown) wound around the chain ring 13 of the external rotating body 16, causing the bicycle to move forward. Then, when the input energy decreases while the bicycle is moving forward and the force compressing the elastically deformable bodies 17 weakens, each elastically deformable body 17 expands (restores) and presses against the adjacent protrusions 24, so that the energy accumulated in each elastically deformable body 17 can be used to rotate the external rotating body 16 in the direction of arrow a in Figure 3, moving the bicycle forward. Therefore, when a bicycle user gets tired on a slope or the like and his / her pedaling power weakens, the energy stored in the elastically deformable body 17 can be effectively used as power (rotational force) to move the bicycle forward, thereby reducing the burden on the user.

[0026] As shown in FIGS. 2, 6, and 7, a plurality of (here, five) locking claws 28 are formed at circumferential intervals on the other axial side of the outer tube portion 23. Furthermore, as shown in FIGS. 2 and 8, a plurality of (here, five) locking holes 29 are formed on one axial side of the chainring 13, corresponding to the locking claws 28 of the outer tube portion 23. The locking claws 28 are engaged with the locking holes 29, thereby fixing the chainring 13 to the outer tube portion 23. At this time, as shown in FIGS. 1 and 2, the outer periphery of the contact surface between the outer tube portion 23 of the external rotating body 16 and the chainring 13 is sealed with a sealant 30, thereby reliably integrating the outer tube portion 23 and the chainring 13 and preventing foreign matter such as rainwater and gravel from entering the interior of the external rotating body 16 through the gap between the outer tube portion 23 and the chainring 13. The material of the sealant 30 is selected appropriately.

[0027] 1 and 2, a side plate cover material 31 is attached to one axial side of the side plate portion 22 of the external rotating body 16 so as to fit along the periphery of the crank arm mounting hole 26, and a chain ring cover material 32 is attached to the other axial side of the chain ring 13 so as to fit along the periphery of the crank shaft insertion hole 27. The side plate cover material 31 and the chain ring cover material 32 are preferably made of a soft rubber plate, a felt sheet, or a plurality of bristles arranged in a circular pattern along the crank arm mounting hole 26 and the crank shaft insertion hole 27, but are not limited to these. In this embodiment, a circular felt sheet is used as the side plate cover material 31, and a plurality of bristles 34 are attached radially to the inner periphery of a circular base material 33 as the chain ring cover material 32, but the shapes, materials, etc. of the side plate cover material 31 and the chain ring cover material 32 may be the same or different.

[0028] Furthermore, when the side plate cover material 31 (as well as the chain ring cover material 32) is formed from a soft rubber plate or felt sheet, it is preferable that the center side be curved in an arc shape toward the outside of the external rotating body 16, as shown in Figure 2, but it may also be inclined in a linear shape. Furthermore, when the tips (axial center side) of the side plate covering material 31 and the chain ring covering material 32 come into contact with the first crank arm 11a and the bearing portion 14, it causes resistance to the transmission of rotation, so it is necessary to leave a small gap between the center side of the side plate covering material 31 and the first crank arm 11a, and between the center side of the chain ring covering material 32 (the tip side of the bristles 34) and the crank shaft 12. However, most of the gap between the crank arm mounting hole 26 and the first crank arm 11a and the gap between the crank shaft insertion hole 27 and the crank shaft 12 are covered by the side plate covering material 31 and the chain ring covering material 32, and the side plate covering material 31 and the chain ring covering material 32 can repel rainwater, gravel, and other foreign matter to the outside of the external rotating body 16, thereby protecting the inside of the external rotating body 16.

[0029] Furthermore, in this embodiment, as shown in FIG. 2 , a side plate gasket 35a is attached to the other axial side of the side plate portion 22 of the external rotating body 16 so as to fit along the periphery of the crank arm mounting hole 26, and a chain ring gasket 35b is attached to one axial side of the chain ring 13 so as to fit along the periphery of the crank shaft insertion hole 27. The side plate gasket 35a and the chain ring gasket 35b are made of rubber and, like the side plate covering material 31 and the chain ring covering material 32, prevent rainwater, gravel, and other foreign matter from entering the interior of the external rotating body 16. By attaching the side plate gasket 35a and the chain ring gasket 35b to the external rotating body 16 in addition to the side plate covering material 31 and the chain ring covering material 32, the interior of the external rotating body 16 can be doubly protected from foreign matter, but either one of the side plate covering material 31 and the side plate gasket 35a may be omitted, and either one of the chain ring covering material 32 and the chain ring gasket 35b may be omitted. Furthermore, since the side plate gasket 35a is not in contact with the first crank arm 11a and the internal rotating body 15 (main body portion 20), and the chain ring gasket 35b is not in contact with the bearing portion 14 and the internal rotating body 15 (main body portion 20), the side plate gasket 35a and the chain ring gasket 35b can be prevented from causing resistance when the internal rotating body 15 and the external rotating body 16 rotate relative to each other.

[0030] Bearings (not shown) may be attached between the first crank arm 11a and the side plate portion 22 of the external rotating body 16 (in the crank arm mounting hole 26) and between the bearing portion 14 and the disc portion 39 of the chainring 13 (in the crank shaft insertion hole 27). The bearings align the axial centers of the internal rotating body 15 and the external rotating body 16, enabling smooth relative rotation between the internal rotating body 15 and the external rotating body 16, and preventing foreign matter from entering the interior of the external rotating body 16 through the crank arm mounting hole 26 and the crank shaft insertion hole 27. In this case, some or all of the side plate covering material 31, the chainring covering material 32, the side plate gasket 35a, and the chainring gasket 35b may be omitted.

[0031] As shown in Fig. 2, the other axial side of each protrusion 24 is fixed to the chainring 13 by a fixing means 36. This allows the side plate portion 22 and the chainring 13 to be integrated via each protrusion 24, so that when the internal rotating body 15 and the external rotating body 16 rotate relative to each other, each protrusion 24 reliably compresses each elastically deformable body 17, allowing energy input from the internal rotating body 15 to be transmitted to the external rotating body 16 without waste and output from the chainring 13. In this embodiment, to facilitate attachment and detachment of the chainring 13 during maintenance such as replacement of the elastically deformable body 17, a female screw 37 is formed in the center of each protrusion 24, and the chainring 13 and each protrusion 24 are fixed using a male screw that screws into the female screw 37 as the fixing means 36. However, the fixing means 36 is not limited to this and can be selected as appropriate.

[0032] As shown in FIG. 3 , each elastically deformable body 17 is formed in a cylindrical shape with a through-hole 38 parallel to the axial direction of the crankshaft 12. As a result, when compressed by each protrusion 24, each elastically deformable body 17 deforms more (is more easily crushed) than an elastically deformable body formed in a solid cylindrical or spherical shape, thereby reducing the load on the user pedaling the bicycle. Furthermore, the increased deformation of each elastically deformable body 17 increases the energy stored in each elastically deformable body 17, thereby increasing the restoring force and improving the assist capability. While silicone rubber is preferably used as the material for the elastically deformable body 17, this is not a limitation. Other synthetic rubbers such as butadiene rubber or urethane rubber may also be used, or elastomers (particularly thermoplastic elastomers) may also be used. Furthermore, the elastically deformable body 17 may be made of a single material or a composite material, and may be formed, for example, by laminating multiple elastic members with different physical properties (hardness and elasticity) in the radial direction.

[0033] The number of spaces 21 formed in the main body 20 of the internal rotor 15 and the corresponding number of protrusions 24 provided on the external rotor 16 can be selected as appropriate. The spaces 21 and protrusions 24 are preferably arranged at equal angular intervals. In this embodiment, the elastically deformable body 17 is arranged only on one longitudinal side of each space 21 (the side compressed by the protrusions 24 due to the relative rotation of the internal rotor 15 and the external rotor 16 when the bicycle is moving forward). However, in addition to the elastically deformable body 17, an auxiliary elastically deformable body (not shown) may be arranged on the other longitudinal side of each space 21. The auxiliary elastically deformable body functions as a damper, preventing the protrusions 24 from directly colliding with the main body 20 as they move along the spaces 21, thereby absorbing impact. The shape, size, material, etc. of the auxiliary elastic deformation body are selected appropriately, and these may be the same as or different from the elastic deformation body 17.

[0034] As shown in FIGS. 1, 2, and 8, the chainring 13 includes a disk portion 39 that covers the opening on the other axial side of the external rotating body 16 and a gear portion 40 around which a chain (not shown) is wound around the outer periphery of the disk portion 39. Multiple (here, five) connecting portions 41 connect the disk portion 39 and the gear portion 40. The shape, number, and arrangement of the connecting portions 41 may be selected as appropriate. The disk portion 39 also has fixing holes 42 for fixing the protrusions 24. In this embodiment, the connecting portions 41 connect the outer periphery of the disk portion 39 and the inner periphery of the gear portion 40 at an angle (intersecting the axial direction of the crankshaft) so that the gear portion 40 is located in the axial center of the outer cylindrical portion 23 of the external rotating body 16. However, as in the modified chainring 13A shown in FIG. 9, the connecting portions 41 may be formed along the outer periphery of the outer cylindrical portion 23 of the external rotating body 16 (parallel to the axial direction of the crankshaft).

[0035] Although the embodiments of the present invention have been described above, the present invention is not limited to the above-described embodiments, but also includes other embodiments and modifications that are possible within the scope of the claims, and all changes in conditions that do not deviate from the gist of the present invention are within the scope of application of the present invention. Of the parts that make up the bicycle rotation transmission mechanism, metals such as stainless steel are preferably used for parts for which no particular material is specified, but various materials may be selected as appropriate, and synthetic resins (including reinforced plastics) or wood may also be used. The bicycle rotation transmission mechanism can be attached to the crankshaft of an existing bicycle to provide (add) an assist function, but it may also be incorporated into the crankshaft of a newly manufactured bicycle from the beginning. [Explanation of symbols]

[0036] 10: Bicycle rotation transmission mechanism, 11a: First crank arm, 11b: Second crank arm, 12: Crankshaft, 13, 13A: Chain ring, 14: Bearing portion (bottom bracket), 15: Internal rotating body, 16: External rotating body, 17: Elastically deformable body, 19: Crankshaft mounting portion, 20: Main body portion, 21: Space portion, 22: Side plate portion, 23: Outer cylinder portion, 24: Protrusion portion, 2 6: crank arm mounting hole, 27: crank shaft insertion hole, 28: locking claw, 29: locking hole, 30: sealing material, 31: side plate cover material, 32: chain ring cover material, 33: base material, 34: bristle material, 35a: side plate gasket, 35b: chain ring gasket, 36: fixing means, 37: female screw, 38: through hole, 39: disc portion, 40: gear portion, 41: connecting portion, 42: fixing hole

Claims

1. A bicycle rotation transmission mechanism is attached to one longitudinal side of a bicycle crankshaft, the bicycle crankshaft having a first crank arm attached to one longitudinal side and a second crank arm attached to the other longitudinal side, an internal rotating body attached to a base side of the first crank arm and rotating together with the crankshaft; an external rotating body held on the internal rotating body so as to be rotatable in forward and reverse directions and equipped with a chain ring; and an elastically deformable body which elastically deforms when the internal rotating body and the external rotating body rotate relative to each other and transmits rotation between the internal rotating body and the external rotating body, the internal rotating body has a main body portion formed with a crankshaft attachment portion to which a base side of the first crank arm is attached, and the main body portion has a plurality of arc-shaped spaces that penetrate the main body portion in the axial direction, curve concentrically around the axis of the main body portion, and accommodate the elastically deformable bodies; the external rotating body has a side plate portion arranged on one axial side of the internal rotating body, the chain ring arranged on the other axial side of the internal rotating body facing the side plate portion, an outer cylindrical portion that is continuous with the outer periphery of the side plate portion, is connected to the chain ring, and covers the outer periphery of the internal rotating body; and a protrusion that protrudes from the other axial side of the side plate portion, is inserted into the respective spaces of the main body portion of the internal rotating body, and presses the respective elastically deformable bodies when the bicycle is moved forward; the side plate portion is formed with a crankarm attachment hole into which a base side of the first crank arm attached to the crankshaft attachment portion is loosely fitted, and the chain ring is formed with a crankshaft insertion hole into which one longitudinal side of the crankshaft connected to the base side of the first crank arm is loosely fitted. a rotation transmission mechanism for a bicycle, which transmits rotation input from the first crank arm and the second crank arm to the internal rotating body to the chain ring of the external rotating body when the bicycle is moving forward.

2. 2. A rotation transmission mechanism for a bicycle as described in claim 1, characterized in that it has a plurality of locking pawls formed at intervals in the circumferential direction on the other axial side of the outer cylindrical portion of the external rotating body, and a plurality of locking holes formed on one axial side of the chain ring corresponding to each of the locking pawls, and each of the locking pawls is engaged with each of the locking holes to fix the chain ring to the outer cylindrical portion.

3. 2. The bicycle rotation transmission mechanism according to claim 1, further comprising a sealant for sealing the outer periphery of the contact surface between the outer cylindrical portion of the external rotating body and the chain ring.

4. 2. The rotation transmission mechanism for a bicycle according to claim 1, further comprising a side plate cover material attached to the periphery of the crank arm mounting hole on one axial side of the side plate portion of the external rotating body, and a chain ring cover material attached to the periphery of the crank shaft insertion hole on the other axial side of the chain ring.

5. 2. The bicycle rotation transmission mechanism according to claim 1, wherein the external rotating body has fixing means for fixing the other axial side of each of the protrusions to the chain ring.

6. 2. The bicycle rotation transmission mechanism according to claim 1, wherein each of the elastically deformable bodies is formed in a cylindrical shape having a through hole parallel to the axial direction of the crankshaft.

7. 7. The bicycle rotation transmission mechanism according to claim 6, wherein each of the elastically deformable bodies is formed by laminating a plurality of elastic members with different physical properties in a radial direction.

8. A bicycle comprising a rotation transmission mechanism for a bicycle according to any one of claims 1 to 7 mounted on one longitudinal side of a crankshaft.

Images