Bicycle transmission apparatus

A bicycle transmission apparatus comprises a base member, an input shaft, a first transmission member, a second transmission member, and a first coupling member. The base member is configured to be attached to a bicycle frame as a separate member from the bicycle frame. The first transmission member is rotatable relative to the base member about a first rotational axis different from the input rotational axis. The second transmission member is rotatable relative to the base member about a second rotational axis different from each of the input rotational axis and the first rotational axis. The first coupling member is configured to couple the first transmission member to the second transmission member to transmit rotation of the first transmission member to the second transmission member at a variable speed stage.

BACKGROUND OF THE INVENTION

Field of the Invention

The present invention relates to a bicycle transmission apparatus.

Discussion of the Background

Bicycling is becoming an increasingly more popular form of recreation as well as a means of transportation. Moreover, bicycling has become a very popular competitive sport for both amateurs and professionals. Whether the bicycle is used for recreation, transportation or competition, the bicycle industry is constantly improving the various components of the bicycle. One bicycle component that has been extensively redesigned is a transmission apparatus.

SUMMARY OF THE INVENTION

In accordance with a first aspect of the present invention, a bicycle transmission apparatus comprises a base member, an input shaft, a first transmission member, a second transmission member, and a first coupling member. The base member is configured to be attached to a bicycle frame as a separate member from the bicycle frame. The base member includes an internal space. The input shaft is mounted to the base member to receive an input torque and rotatable relative to the base member about an input rotational axis in response to the input torque. The first transmission member is provided in the internal space of the base member and is rotatable relative to the base member about a first rotational axis different from the input rotational axis. The second transmission member is provided in the internal space of the base member and is rotatable relative to the base member about a second rotational axis different from each of the input rotational axis and the first rotational axis. The first coupling member has an annular shape to surround the first rotational axis and the second rotational axis when viewed from an axial direction parallel to the first rotational axis. The first coupling member is configured to couple the first transmission member to the second transmission member to transmit rotation of the first transmission member to the second transmission member at a variable speed stage. The variable speed stage is variable in accordance with at least one positional relationship among the first transmission member, the second transmission member, and the first coupling member in the axial direction.

In accordance with a second aspect of the present invention, the bicycle transmission apparatus according to the first aspect further comprises an output shaft rotatable relative to the base member about the second rotational axis and coupled to the second transmission member to transmit rotation of the second transmission member to a bicycle wheel.

In accordance with a third aspect of the present invention, the bicycle transmission apparatus according to the second aspect is configured so that the input rotational axis and the second rotational axis are spaced apart from each other.

In accordance with a fourth aspect of the present invention, the bicycle transmission apparatus according to the second aspect further comprises an input cogwheel and an output cogwheel. The input cogwheel is configured to be coupled to the input shaft to rotate together with the input shaft relative to the base member about the input rotational axis. The output cogwheel is configured to be coupled to the output shaft to rotate together with the output shaft relative to the base member about the second rotational axis. The input cogwheel is provided on a first side relative to the first transmission member in the axial direction. The output cogwheel is provided on the first side relative to the first transmission member in the axial direction.

In accordance with a fifth aspect of the present invention, the bicycle transmission apparatus according to the first aspect further comprises an input coupling member having an annular shape to surround the input rotational axis and the first rotational axis when viewed from the axial direction. The input coupling member is configured to couple the input shaft to the first transmission member to transmit rotation of the input shaft to the first transmission member.

In accordance with a sixth aspect of the present invention, the bicycle transmission apparatus according to the fifth aspect is configured so that a value obtained by dividing a rotational speed of the first transmission member by a rotational speed of the input shaft is equal to 2 or 4.

In accordance with a seventh aspect of the present invention, the bicycle transmission apparatus according to the fifth aspect is configured so that the input coupling member is provided in the internal space of the base member.

In accordance with an eighth aspect of the present invention, the bicycle transmission apparatus according to the first aspect further comprises a one-way clutch configured to transmit a first rotation of the input shaft to the first transmission member and configured to prevent a second rotation of the input shaft from being transmitted from the input shaft to the first transmission member. The second rotation is opposite to the first rotation about the input rotational axis.

In accordance with a ninth aspect of the present invention, the bicycle transmission apparatus according to the first aspect is configured so that the base member includes an internal space in which the first transmission member and the second transmission member are provided. The base member is configured to store lubricant in the internal space.

In accordance with a tenth aspect of the present invention, the bicycle transmission apparatus according to the ninth aspect is configured so that the base member includes a supply port through which the lubricant is to be supplied to the internal space.

In accordance with an eleventh aspect of the present invention, the bicycle transmission apparatus according to the first aspect is configured so that the base member is configured to be clamped by the bicycle frame.

In accordance with a twelfth aspect of the present invention, the bicycle transmission apparatus according to the eleventh aspect is configured so that the base member includes a base member body and an input shaft support. The first transmission member and the second transmission member are provided in the base member body. The input shaft support includes a support opening in which the input shaft is rotatable relative to the base member about the input rotational axis. The input shaft support extends from the base member body along the input rotational axis. The input shaft support is configured to be clamped by the bicycle frame.

In accordance with a thirteenth aspect of the present invention, the bicycle transmission apparatus according to the first aspect is configured so that the base member is configured to be mounted to a first frame of the bicycle frame and is pivotable relative to a second frame of the bicycle frame about the second rotational axis, the second frame being pivotably coupled to the first frame about the second rotational axis.

In accordance with a fourteenth aspect of the present invention, the bicycle transmission apparatus according to the thirteenth aspect further comprises an output shaft rotatable relative to the base member about the second rotational axis and coupled to the second transmission member to transmit rotation of the second transmission member to a bicycle wheel rotatable relative to the second frame. The output shaft is configured to extend through a support opening of the bicycle frame along the second rotational axis.

In accordance with a fifteenth aspect of the present invention, the bicycle transmission apparatus according to the fourteenth aspect further comprises an inner bearing unit configured to be provided in the support opening of the bicycle frame and configured to rotatably couple the output shaft to the bicycle frame about the second rotational axis via an outer bearing unit provided radially outward of the inner bearing unit. The outer bearing unit is configured to pivotably couple the second frame to the first frame about the second rotational axis.

In accordance with a sixteenth aspect of the present invention, the bicycle transmission apparatus according to the first aspect further comprises an assist device configured to assist pedaling.

In accordance with a seventeenth aspect of the present invention, the bicycle transmission apparatus according to the sixteenth aspect is configured so that the assist device is configured to generate an assist torque inputted to the second transmission member to assist pedaling.

In accordance with an eighteenth aspect of the present invention, the bicycle transmission apparatus according to the sixteenth aspect is configured so that the assist device is provided on a front side of the base member in an attachment state where the bicycle transmission apparatus is attached to the bicycle frame.

In accordance with a nineteenth aspect of the present invention, the bicycle transmission apparatus according to the eighteenth aspect further comprises an electrical power source configured to supply electrical power to the assist device and provided under the base member in the attachment state of the bicycle transmission apparatus.

In accordance with a twentieth aspect of the present invention, the bicycle transmission apparatus according to the sixteenth aspect further comprises a sensing device and an assist controller. The sensing device is configured to sense a pedaling state of a bicycle. The assist controller is configured to control the assist device to input the assist torque to the second transmission member based on the pedaling state sensed by the sensing device.

In accordance with a twenty-first aspect of the present invention, the bicycle transmission apparatus according to the first aspect further comprises an input coupling member is configured to couple the input shaft to the first transmission member to transmit rotation of the input shaft to the first transmission member. The first transmission member is configured to be coupled to the input shaft via the input coupling member to rotate with the input shaft relative to the base member.

In accordance with a twenty-second aspect of the present invention, the bicycle transmission apparatus according to the twenty-first aspect is configured so that the input shaft is configured to be coupled to a crank arm of a bicycle crank as a crank axle of the bicycle crank. The first transmission member includes a shifting facilitation part configured to facilitate shifting the first coupling member relative to the first transmission member in the axial direction. The shifting facilitation part is disposed in a shifting area of the first transmission member when the bicycle crank is disposed at or adjacent to a dead center.

In accordance with a twenty-third aspect of the present invention, the bicycle transmission apparatus according to the first aspect is configured so that the first coupling member comprises a bicycle chain configured to engage with the first transmission member and the second transmission member.

In accordance with a twenty-fourth aspect of the present invention, the bicycle transmission apparatus according to the twenty-third aspect is configured so that the first coupling member has a chain pitch equal to or smaller than 12 mm.

In accordance with a twenty-fifth aspect of the present invention, the bicycle transmission apparatus according to the first aspect further comprises a guide device configured to guide the first coupling member to change at least one of a first relative position between the first coupling member and the first transmission member, and a second relative position between the first coupling member and the second transmission member.

In accordance with a twenty-sixth aspect of the present invention, the bicycle transmission apparatus according to the twenty-fifth aspect is configured so that the guide device includes a guide member and a guide unit. The guide member is contactable with the first coupling member. The guide unit is configured to guide the guide member in a first guide direction different from the axial direction to change at least one of the first relative position and the second relative position.

In accordance with a twenty-seventh aspect of the present invention, the bicycle transmission apparatus according to the twenty-sixth aspect is configured so that the guide device includes a tensioner contactable with the first coupling member. The guide unit is configured to guide the tensioner in a second guide direction to adjust tension of the first coupling member. The second guide direction is different from the first guide direction and the axial direction.

In accordance with a twenty-eighth aspect of the present invention, the bicycle transmission apparatus according to the twenty-seventh aspect is configured so that the guide member and the tensioner are arranged in the second guide direction.

In accordance with a twenty-ninth aspect of the present invention, the bicycle transmission apparatus according to the first aspect is configured so that the first rotational axis and the second rotational axis are parallel to the input rotational axis. A first angle is defined about the first rotational axis between a first line segment connecting the input rotational axis and the first rotational axis and a second line segment connecting the first rotational axis and the second rotational axis when viewed from the axial direction. A second angle is defined about the first rotational axis between the first line segment and the second line segment when viewed from the axial direction. The second angle is defined on an opposite side of the first angle relative to the first rotational axis when viewed from the axial direction. The first angle is smaller than the second angle and is an obtuse angle.

In accordance with a thirtieth aspect of the present invention, the bicycle transmission apparatus according to the first aspect is configured so that the first rotational axis and the second rotational axis are parallel to the input rotational axis. A first angle is defined about the first rotational axis between a first line segment connecting the input rotational axis and the first rotational axis and a second line segment connecting the first rotational axis and the second rotational axis when viewed from the axial direction. A second angle is defined about the first rotational axis between the first line segment and the second line segment when viewed from the axial direction. The second angle is defined on an opposite side of the first angle relative to the first rotational axis when viewed from the axial direction. The first angle is smaller than the second angle and is an acute angle.

DESCRIPTION OF THE EMBODIMENTS

First Embodiment

Referring initially toFIG. 1, a bicycle10is illustrated that is equipped with a bicycle transmission apparatus12in accordance with a first embodiment. While the bicycle10is illustrated as a mountain bike, the bicycle transmission apparatus12can be applied to road bikes or any type of bicycle.

As seen inFIG. 1, the bicycle10includes a handlebar B1, a saddle B2, a bicycle frame B3, a front brake operating device B41, a rear brake operating device B42, a front braking device B51, a rear braking device B52, a front wheel B61, a rear wheel B62, and a bicycle crank B7. The front brake operating device B41is operatively coupled to the front braking device B51via an operation cable. The rear brake operating device B42is operatively coupled to the rear braking device B52via an operation cable. The bicycle crank B7includes crank arms B71and B72each coupled to the bicycle transmission apparatus12to input a pedaling force into the bicycle transmission apparatus12.

In the present application, the following directional terms “front”, “rear”, “forward”, “rearward”, “left”, “right”, “transverse”, “upward” and “downward” as well as any other similar directional terms refer to those directions which are determined on the basis of a user (e.g., a rider) who sits on the saddle B2of the bicycle10with facing the handlebar B1. Accordingly, these terms, as utilized to describe the bicycle transmission apparatus12, should be interpreted relative to the bicycle10equipped with the bicycle transmission apparatus12as used in an upright riding position on a horizontal surface.

The bicycle10includes a shifter14via which the bicycle transmission apparatus12is operated by the user (e.g., the rider) for changing a speed stage of the bicycle transmission apparatus12. The shifter14is mounted to the handlebar B1and is adjacent to the front brake operating device B41, for example. The shifter14can be integrated in at least one of the front brake operating device B41and the rear brake operating device B42if needed and/or desired.

The bicycle transmission apparatus12and the shifter14constitute a bicycle transmission system16. The shifter14is operatively coupled to the bicycle transmission apparatus12. In the illustrated embodiment, the shifter14is electrically connected to the bicycle transmission apparatus12via an electrical control cable. While the bicycle transmission apparatus12is electrically actuated in response to a shift operation of the shifter14in the illustrated embodiment, the shifter14can be mechanically coupled to the bicycle transmission apparatus12if needed and/or desired. Furthermore, the bicycle transmission apparatus12and the shifter14can use a wireless technology if needed and/or desired.

As seen inFIG. 1, the bicycle transmission apparatus12is mounted to the bicycle frame B3. The bicycle transmission apparatus12is configured to transmit the pedaling force to the rear wheel B62at a variable speed stage. The variable speed stage includes speed stages different from each other. While the bicycle transmission apparatus12has thirteen speed stages in the illustrated embodiment, the bicycle transmission apparatus12can have at least two speed stages. Furthermore, the bicycle transmission apparatus12can have a continuously variable speed stage if needed and/or desired.

As seen inFIGS. 2 and 3, the bicycle transmission apparatus12comprises a base member18. The base member18is mounted to the bicycle frame B3and serves as a housing of the bicycle transmission apparatus12. In the illustrated embodiment, the base member18is configured to be attached to the bicycle frame B3as a separate member from the bicycle frame B3. However, at least part of the base member18can be integrally provided with the bicycle frame B3as a single unitary member if needed and/or desired.

In the illustrated embodiment, the bicycle frame B3includes a first frame B31and a second frame B32. The base member18is mounted to the first frame B31as a separate member from the first frame B31. The second frame B32is pivotably coupled to the first frame B31about a pivot axis PA1. The first frame B31includes first sub frames B311and B312spaced apart from each other in a transverse direction D0of the bicycle10. The pivot axis PA1is parallel to the transverse direction D0. The base member18is provided between the first sub frames B311and B312.

The second frame B32includes second sub frames B321and B322spaced apart from each other in the transverse direction D0. The second sub frame B321is coupled to the second sub frame B322as forming a one-piece member. The second sub frame B321is pivotably coupled to the first sub frame B311about the pivot axis PA1. The second sub frame B322is pibotably coupled to the first sub frame B312about the pivot axis PAL

As seen inFIG. 1, the second frame B32is coupled to a hub shaft of a hub assembly of the rear wheel B62. The bicycle frame B3further includes a suspension device B33, a first link B34, and a second link B35. The first link B34is pivotably coupled to the first frame B31. The second link B35is rotatably coupled to the rear wheel B62and one end of the first link B34. The second link B35is rigidly coupled to the second sub frames B321and B322. The second link B35and the second sub frames B321and B322may be integrally provided as a single unitary member. The suspension device B33is pivotably coupled to the first frame B31and the other end of the first link B34for absorbing shock applied to the bicycle frame B3.

As seen inFIG. 4, the bicycle transmission apparatus12comprises a first transmission member20, a second transmission member22, and a first coupling member24. The base member18includes an internal space26in which the first transmission member20and the second transmission member22are provided. The first transmission member20is provided in the internal space26of the base member18. The second transmission member22is provided in the internal space26of the base member18.

As seen inFIG. 4, the first transmission member20is rotatable relative to the base member18about a first rotational axis A1. The second transmission member22is rotatable relative to the base member18about a second rotational axis A2.

As seen inFIG. 4, the first coupling member24is configured to couple the first transmission member20to the second transmission member22to transmit rotation of the first transmission member20to the second transmission member22at a variable speed stage. The first coupling member24has an annular shape to surround the first rotational axis A1and the second rotational axis A2when viewed from an axial direction D1(FIG. 5) parallel to the first rotational axis A1. In the illustrated embodiment, the first coupling member24comprises a bicycle chain configured to engage with the first transmission member20and the second transmission member22. The first coupling member24has a chain pitch equal to or smaller than 12 mm, for example. The chain pitch is more preferably equal to or smaller than 10 mm. The chain pitch is further more preferably equal to or smaller than 8.4 mm. The first coupling member24can comprise a coupling member such as a coupling belt.

As seen inFIG. 5, the second rotational axis A2is parallel to the first rotational axis A1in the illustrated embodiment. However, the second rotational axis A2can be non-parallel to the first rotational axis A1if needed and/or desired. The first rotational axis A1and the second rotational axis A2are parallel to the transverse direction D0of the bicycle10.

As seen inFIGS. 5 and 6, the bicycle transmission apparatus12further comprises an input shaft28. The input shaft28is mounted to the base member18(FIG. 6) to receive an input torque. The input shaft28is rotatable relative to the base member18(FIG. 6) about an input rotational axis A3in response to the input torque. The bicycle transmission apparatus12further comprises input bearing assemblies29. The input shaft28is rotatably mounted to the base member18(FIG. 6) via the input bearing assemblies29(FIG. 5).

As seen inFIGS. 6 and 7, the input shaft28is configured to be coupled to a crank arm of the bicycle crank B7as a crank axle of the bicycle crank B7. In the illustrated embodiment, the input shaft28is configured to be coupled to the crank arms B71and B72of the bicycle crank B7as the crank axle of the bicycle crank B7. The input shaft28includes a first axle end28aand a second axle end28bopposite to the first axle end28a. The first axle end28ais provided outside the base member18. The second axle end28bis provided outside the base member18. The crank arm B71is coupled to the first axle end28a. The crank arm B72is coupled to the second axle end28b.

As seen inFIGS. 6 and 7, the base member18includes a base member body18aand an input shaft support18b. In the illustrated embodiment, the base member18includes two input shaft supports18b. As seen inFIG. 4, the first transmission member20and the second transmission member22are provided in the base member body18a. As seen inFIGS. 6 and 7, the input shaft support18bincludes a support opening18cin which the input shaft28is rotatable relative to the base member18about the input rotational axis A3. The input shaft support18bextends from the base member body18aalong the input rotational axis A3.

As seen inFIGS. 2 and 3, the base member18is configured to be clamped by the bicycle frame B3. In the illustrated embodiment, the input shaft support18bis configured to be clamped by the bicycle frame B3. The bicycle frame B3includes a clamp member B313. The clamp member B313is secured to the first frame B31via clamp bolts (not shown) to sandwich the input shaft support18bbetween the first frame B31and the clamp member B313. Namely, the bicycle frame B3does not include a bottom bracket shell which rotatably supports the input shaft28, and the input shaft support18bof the base member18serves as the bottom bracket shell. The base member18is secured to the bicycle frame B3via fasteners (not shown) so as to prevent the base member18from rotating relative to the bicycle frame B3about the input rotational axis A3. The base member18can just be in contact with the bicycle frame B3without such fasteners so as to prevent the base member18from rotating relative to the bicycle frame B3about the input rotational axis A3.

As seen inFIG. 5, the bicycle transmission apparatus12further comprises an input coupling member30. The input coupling member30is configured to couple the input shaft28to the first transmission member20to transmit rotation of the input shaft28to the first transmission member20. The first transmission member20is configured to be coupled to the input shaft28via the input coupling member30to rotate with the input shaft28relative to the base member18.

As seen inFIG. 4, the input coupling member30has an annular shape to surround the input rotational axis A3and the first rotational axis A1when viewed from the axial direction D1. The input coupling member30is provided in the internal space26of the base member18. In the illustrated embodiment, the input coupling member30comprises a bicycle chain configured to couple the input shaft28to the first transmission member20. The input coupling member30has a chain pitch equal to or smaller than 12 mm, for example. The input coupling member30can comprise a coupling member such as a coupling belt.

As seen inFIG. 5, the bicycle transmission apparatus12further comprises an input cogwheel31. The input cogwheel31is configured to be coupled to the input shaft28to rotate together with the input shaft28relative to the base member18about the input rotational axis A3.

As seen inFIG. 4, the bicycle transmission apparatus12further comprises a one-way clutch32. The one-way clutch32is configured to transmit a first rotation R1of the input shaft28to the first transmission member20and is configured to prevent a second rotation R2of the input shaft28from being transmitted from the input shaft28to the first transmission member20. The second rotation R2is opposite to the first rotation R1about the input rotational axis A3.

As seen inFIG. 8, the one-way clutch32is configured to couple the input cogwheel31to the input shaft28and is provided between the input shaft28and the input cogwheel31. As seen inFIG. 4, the one-way clutch32is configured to transmit the first rotation R1of the input shaft28to the input cogwheel31and is configured to prevent the second rotation R2of the input shaft28from being transmitted from the input shaft28to the input cogwheel31. The one-way clutch32can be omitted from the bicycle transmission apparatus12if needed and/or desired.

As seen inFIG. 8, the bicycle transmission apparatus12further comprises a first shaft33and an intermediate cogwheel34. The first shaft33defines the first rotational axis A1. The first transmission member20is rotatable relative to the first shaft33about the first rotational axis A1. The intermediate cogwheel34is rotatable relative to the first shaft33about the first rotational axis A1. The intermediate cogwheel34is coupled to the first transmission member20to rotate together with the first transmission member20relative to the base member18about the first rotational axis A1. The bicycle transmission apparatus further comprises first bearing assemblies35. The first shaft33is rotatably mounted to the base member18about the first rotational axis A1via the first bearing assemblies35.

As seen inFIG. 5, the intermediate cogwheel34is coupled to the input cogwheel31via the input coupling member30. The input coupling member30is configured to couple the input cogwheel31to the intermediate cogwheel34to transmit rotation of the input shaft28to the first transmission member20. The input cogwheel31comprises a sprocket including teeth. The intermediate cogwheel34comprises a sprocket including teeth. The input shaft28is configured to be coupled to the first transmission member20via the input cogwheel31, the input coupling member30, and the intermediate cogwheel34to rotate with the input shaft28relative to the base member18.

For example, a value obtained by dividing a rotational speed of the first transmission member20by a rotational speed of the input shaft28is equal to 2 or 4. Especially, when the one-way clutch32is omitted from the bicycle transmission apparatus12, the value is preferably equal to 2 or 4. In the illustrated embodiment, the value obtained by dividing the rotational speed of the first transmission member20by the rotational speed of the input shaft28is equal to 2. However, the value obtained by dividing the rotational speed of the first transmission member20by the rotational speed of the input shaft28can be equal to 4 or other values. If the one-way clutch32is omitted from the bicycle transmission apparatus12, the value is selected to 2 or 4, a phase between the crank arm B71and the first cogwheels CW11to CW17is adjusted so that, when the crank arm B71is in the upper or lower dead center area, the first shifting facilitation part46of the first cogwheels CW11to CW17is in a sifting area of the guide member78. Thus, the transmission apparatus12shifts the first coupling member24when the torque of the first cogwheels CW11to CW17becomes the lowest.

As seen inFIG. 8, the bicycle transmission apparatus12further comprises an output shaft36. The output shaft36is rotatable relative to the base member18about the second rotational axis A2. The second transmission member22is coupled to the output shaft36to rotate together with the output shaft36relative to the base member18about the second rotational axis A2. The bicycle transmission apparatus12further comprises output bearing assemblies37. The output shaft36is rotatably mounted to the base member18via the output bearing assemblies37.

As seen inFIG. 8, the bicycle transmission apparatus12further comprises an output cogwheel38. The output cogwheel38is configured to be coupled to the output shaft36to rotate together with the output shaft36relative to the base member18about the second rotational axis A2. Namely, the second transmission member22, the output shaft36, and the output cogwheel38are rotatable integrally with each other relative to the base member18about the second rotational axis A2. The output cogwheel38comprises a sprocket including teeth. The pedaling force is transmitted from the input shaft28to the output cogwheel38via the input cogwheel31, the input coupling member30, the intermediate cogwheel34, the first transmission member20, the first coupling member24, the second transmission member22, and the output shaft36.

In the illustrated embodiment, the input cogwheel31is provided on a first side S1relative to the first transmission member20in the axial direction D1. The intermediate cogwheel34is provided on the first side S1relative to the first transmission member20in the axial direction D1. The output cogwheel38is provided on the first side S1relative to the first transmission member20in the axial direction D1.

As seen inFIG. 6, the output cogwheel38is provided outside the base member18. As seen inFIGS. 1 and 6, an output coupling member40such as a bicycle chain engages with the output cogwheel38and a rear sprocket B9(FIG. 1) of the bicycle10. As seen inFIG. 1, the rear sprocket B9is coupled to the rear wheel B62via a freewheel (not shown) to rotatable integrally with the rear wheel B62in a rotational driving direction. Rotation of the output cogwheel38is transmitted to the rear wheel B62via the output coupling member40and the rear sprocket B9.

As seen inFIG. 5, the first rotational axis A1is different from the input rotational axis A3. The second rotational axis A2is different from each of the input rotational axis A3and the first rotational axis A1. The input rotational axis A3and the second rotational axis A2are spaced apart from each other. The first rotational axis A1and the second rotational axis A2are parallel to the input rotational axis A3. However, the first rotational axis A1can coincide with the input rotational axis A3if needed and/or desired. In such an embodiment, the input shaft28is coaxial with the first transmission member20and is coupled to the first transmission member20to rotate together with the first transmission member20relative to the base member18about the first rotational axis A1.

As seen inFIG. 4, a first angle AG11is defined about the first rotational axis A1between a first line segment L1connecting the input rotational axis A3and the first rotational axis A1and a second line segment L2connecting the first rotational axis A1and the second rotational axis A2when viewed from the axial direction D1. A second angle AG12is defined about the first rotational axis A1between the first line segment L1and the second line segment L2when viewed from the axial direction D1. The second angle AG12is defined on an opposite side of the first angle AG11relative to the first rotational axis A1when viewed from the axial direction D1. The first angle AG11is smaller than the second angle AG12and is an obtuse angle. The first angle AG11is smaller than 180 degrees and larger than 90 degrees. However, the first angle AG11can be an acute angle if needed and/or desired.

As seen inFIG. 8, the first transmission member20is movable relative to the base member18in the axial direction D1parallel to the first rotational axis A1. The second transmission member22is stationary relative to the base member18in the axial direction D1. In the illustrated embodiment, the first transmission member20is movable relative to the base member18and the second transmission member22between a first axial position P1and a second axial position P2in the axial direction D1.

The variable speed stage of the bicycle transmission apparatus12is variable in accordance with at least one positional relationship among the first transmission member20, the second transmission member22, and the first coupling member24in the axial direction D1. The axial direction D1includes a first axial direction D11and a second axial direction D12opposite to the first axial direction D11.

The first transmission member20includes first cogwheels CW11to CW17arranged in the axial direction D1. Each of the first cogwheels CW11to CW17is engageable with the first coupling member24. The first cogwheels CW11to CW17respectively define the speed stages together with the second cogwheels CW21to CW27. The second transmission member22includes second cogwheels CW21to CW27arranged in the axial direction D1. Each of the second cogwheels CW21to CW27is engageable with the first coupling member24. The second cogwheels CW21to CW27respectively define the speed stages together with the first cogwheels CW11to CW17.

As seen inFIG. 8, a total number of the first cogwheels CW11to CW17is equal to a total number of the second cogwheels CW21to CW27. In the illustrated embodiment, the first transmission member20includes seven first cogwheels CW11to CW17arranged in the axial direction D1. The second transmission member22includes seven second cogwheels CW21to CW27arranged in the axial direction D1. A total number of the first cogwheels can be different from a total number of the second cogwheels if needed and/or desired.

In the illustrated embodiment, the first cogwheels CW11to CW17are spaced apart from each other in the axial direction D1at a regular interval. The second cogwheels CW21to CW27are spaced apart from each other in the axial direction D1at a regular interval equal to the regular interval of the first cogwheels CW11to CW17.

The first cogwheel CW11is disposed at an axial position substantially equal to an axial position of the second cogwheel CW27in a first state where the first transmission member20is positioned at the first axial position P1. The first cogwheel CW12is disposed at an axial position substantially equal to the axial position of the second cogwheel CW27in a second state where the first transmission member20is positioned at the second axial position P2. The first cogwheels CW11to CW17are respectively disposed at axial positions equal to axial positions of the second cogwheels CW27to CW21in the first state of the first transmission member20. The first cogwheels CW12to CW17are respectively disposed at axial positions equal to axial positions of the second cogwheels CW27to CW22in the second state of the first transmission member20.

As seen inFIG. 9, the first cogwheels CW11to CW17include a first largest cogwheel CW17and a first smallest cogwheel CW11. The first smallest cogwheel CW11has an outer diameter smaller than an outer diameter of the first largest cogwheel CW17. As seen inFIG. 8, the first smallest cogwheel CW11is spaced apart from the first largest cogwheel CW17in the first axial direction D11.

As seen inFIG. 10, the second cogwheels CW21to CW27include a second largest cogwheel CW27and a second smallest cogwheel CW21. The second smallest cogwheel CW21has an outer diameter smaller than an outer diameter of the second largest cogwheel CW27. As seen inFIG. 8, the second smallest cogwheel CW21is spaced apart from the second largest cogwheel CW27in the second axial direction D12.

As seen inFIG. 9, each of the first cogwheels CW11to CW17includes first teeth42arranged in a circumferential direction D2of the first transmission member20. The first cogwheels CW11to CW17respectively have first pitch circles each defined by the first teeth42. The first transmission member20rotates about the first rotational axis A1in a driving rotational direction D21during pedaling.

As seen inFIG. 10, each of the second cogwheels CW21to CW27includes second teeth44arranged in a circumferential direction D3of the second transmission member22. The second cogwheels CW21to CW27respectively have second pitch circles each defined by the second teeth44. The second transmission member22rotates about the second rotational axis A2in a driving rotational direction D31during pedaling.

As seen inFIGS. 9 and 10, first diameters DM11to DM17of the first pitch circles respectively are equal to second diameters DM21to DM27of the second pitch circles. Namely, the second cogwheels CW21to CW27respectively have substantially the same constructions as constructions of the first cogwheels CW11to CW17. However, the second cogwheels CW21to CW27can respectively have different constructions from the constructions of the first cogwheels CW11to CW17if needed and/or desired.

As seen inFIG. 9, the first transmission member20includes a first shifting facilitation part configured to facilitate shifting the first coupling member24relative to the first transmission member20in the axial direction D1. In the illustrated embodiment, at least one of the first cogwheels CW11to CW17of the first transmission member20includes a first shifting facilitation part46configured to facilitate shifting the first coupling member24relative to the first transmission member20in the axial direction D1. Each of the first cogwheels CW12to CW17includes the first shifting facilitation parts46. The first shifting facilitation parts46are recessed in the axial direction D1to guide the first coupling member24from a currently engaged cogwheel to an adjacent larger cogwheel in the first cogwheels CW11to CW17when changing a speed stage.

The first shifting facilitation part46is disposed in a first shifting area48of the first transmission member20when the bicycle crank B7is disposed at or adjacent to a dead center DC1(FIG. 4). As seen inFIG. 4, in a state where the bicycle crank B7is disposed at the dead center DC1, the crank arms B71and B72extend in a vertical direction D4.

As seen inFIG. 10, the second transmission member22includes a second shifting facilitation part configured to facilitate shifting the first coupling member24relative to the second transmission member22in the axial direction D1. In the illustrated embodiment, at least one of the second cogwheels CW21to CW27of the second transmission member22includes a second shifting facilitation part50configured to facilitate shifting the first coupling member24relative to the second transmission member22in the axial direction D1. Each of the second cogwheels CW22to CW27includes the second shifting facilitation parts50. The second shifting facilitation parts50are recessed in the axial direction D1to guide the first coupling member24from a currently engaged cogwheel to an adjacent larger cogwheel in the second cogwheels CW22to CW27when changing a speed stage.

As seen inFIG. 11, the bicycle transmission apparatus12further comprises a bearing structure52. The bearing structure52is configured to rotatably couple the first transmission member20to the first shaft33about the first rotational axis A1. The first transmission member20has a first opening54. The first shaft33extends through the first opening54. The bearing structure52is provided in the first opening54.

The first shaft33is rotatable relative to the base member18. The first shaft33is restricted from moving relative to the base member18in the axial direction D1. The bearing structure52is configured to movably couple the first transmission member20to the first shaft33in the axial direction D1. Namely, the first transmission member20is rotatable relative to the base member18and the first shaft33and is movable relative to the base member18and the first shaft33in the axial direction D1. Unlike the first transmission member20, the intermediate cogwheel34is stationary relative to the base member18in the axial direction D1.

As seen inFIG. 11, the bicycle transmission apparatus12further comprises a positioning device56configured to position the first transmission member20relative to the base member18in the axial direction D1at each of axial positions. The positioning device56is configured to position the first transmission member20relative to the base member18in the axial direction D1at each of the first axial position P1and the second axial position P2. The first transmission member20is movable relative to the base member18in the first axial direction D11from the first axial position P1to the second axial position P2. The first transmission member20is movable relative to the base member18in the second axial direction D12from the second axial position P2to the first axial position P1.

In the illustrated embodiment, the positioning device56includes a holder58, rolling elements60, and a retainer62. The holder58is rotatable relative to the first transmission member20and the first shaft33about the first rotational axis A1. The holder58is movable integrally with the first transmission member20relative to the base member18and the first shaft33in the axial direction D1. The holder58has a tubular shape. The rolling elements60and the retainer62are provided in the holder58. The retainer62is configured to rotatably hold the rolling elements60and is attached to the holder58to move integrally with the holder58in the axial direction D1.

The first shaft33includes a guide groove64configured to guide the rolling elements60in the axial direction D1. The guide groove64is provided on an outer peripheral surface of the first shaft33in a spiral manner. The rolling elements60are provided in the guide groove64and are arranged around the first shaft33along the guide groove64. The holder58, the rolling elements60, the retainer62, and the guide groove64constitute a ball screw configured to convert rotation of the first shaft33into linear motion of the first transmission member20. Rotation of the first shaft33relative to the base member18moves the holder58, the rolling elements60, and the retainer62relative to the first shaft33and the base member18in the axial direction D1. This moves the first transmission member20relative to the base member18in the axial direction D1.

The bicycle transmission apparatus12further comprises a switching device66configured to switch a position of the first transmission member20relative to the base member18in the axial direction D1between the first axial position P1and the second axial position P2.

In the illustrated embodiment, the switching device66includes a switching actuator68, a driven gear70, a reduction structure72, and a reverse-input prevention element74. The switching actuator68, the driven gear70, the reduction structure72, and the reverse-input prevention element74are provided in the base member18and are mounted to the base member18. The reduction structure72includes some gears to decelerate an input rotation from the actuator69and to output decelerated rotation to the driven gear70. The switching actuator68is configured to generate an actuating force to move the first transmission member20relative to the base member18in the axial direction D1. While the switching actuator68is a stepper motor in the illustrated embodiment, the switching actuator68can be a direct-current (DC) motor or other type of actuators if needed and/or desired. The driven gear70is coupled to the first shaft33to rotate integrally with the first shaft33about the first rotational axis A1. An output gear of the reduction structure72meshes with the driven gear70to transmit rotation to the driven gear70relative to the base member18about the first rotational axis A1at a specific gear ratio. The reduction structure72is a reduction gear, for example.

The reverse-input prevention element74is configured to transmit the actuating force from the switching actuator68to the reduction structure72. Specifically, the reverse-input prevention element74is configured to transmit rotation from the switching actuator68to the reduction structure72in both rotational directions. On the other hand, the reverse-input prevention element74is further configured to prevent rotation of the reduction structure72from being transmitted from the reduction structure72to the switching actuator68. The reverse-input prevention element74can be omitted from the switching device66if needed and/or desired.

Other structures can be applied to the switching device66. For example, it is possible to directly move the first transmission member20relative to the base member18using structures such as gears or cams if needed and/or desired.

As seen inFIGS. 12 and 13, the bicycle transmission apparatus12further comprises a guide device76. The guide device76is configured to guide the first coupling member24to change at least one of a first relative position between the first coupling member24and the first transmission member20, and a second relative position between the first coupling member24and the second transmission member22.

The guide device76includes a guide member78and a guide unit80. The guide member78is contactable with the first coupling member24. The guide unit80is configured to guide the guide member78in a first guide direction D5to change at least one of the first relative position and the second relative position. The guide unit80is provided in the base member18and are mounted to the base member18. In the illustrated embodiment, the first guide direction D5is not parallel to the axial direction D1. However, the first guide direction D5can be parallel to the axial direction D1if needed and/or desired.

As seen inFIG. 13, the guide member78includes a guide opening81through which the first coupling member24extends. The guide member78is slidable with the first coupling member24to move (shift) the first coupling member24in the first guide direction D5.

As seen inFIGS. 12 and 13, the guide unit80includes a guide shaft82and a coupling structure84. The guide shaft82is rotatable relative to the base member18about a guide rotational axis A4parallel to the first guide direction D5. The guide shaft82is rotatably mounted to the base member18via bearing units (not shown). The coupling structure84is configured to rotatably couple the guide shaft82to the guide member78. The guide shaft82and the coupling structure84constitute a ball screw configured to convert rotation of the guide shaft82into a linear motion of the guide member78.

As seen inFIG. 13, the guide unit80further includes a sub shaft85extending along the guide shaft82in the first guide direction D5. The sub shaft85extends through a hole (not shown) of the coupling structure84to prevent the coupling structure84from rotating relative to the base member18about the guide rotational axis A4.

As seen inFIG. 13, the guide device76includes a guide actuator86configured to move the guide member78in the first guide direction D5. The guide actuator86is configured to generate an actuating force to rotate the guide shaft82relative to the base member18about the guide rotational axis A4. The guide device76includes an intermediate gear88configured to transmit rotation of the guide actuator86to the guide shaft82at a specific gear ratio. The intermediate gear88is a reduction gear, for example.

While the guide device76includes the guide actuator86configured to move the guide member78in response to the input shift signal in the illustrated embodiment, the guide member78can be operated via a mechanical control cable such as a Bowden cable.

As seen inFIGS. 4 and 13, the guide device76includes a tensioner90contactable with the first coupling member24. In the illustrated embodiment, the tensioner90comprises a tension pulley configured to engage with the first coupling member24. The guide unit80is configured to guide the tensioner90in a second guide direction D6to adjust tension of the first coupling member24. The second guide direction D6is different from the first guide direction D5and the axial direction D1. The guide member78and the tensioner90are arranged in the second guide direction D6. The second guide direction D6is preferably perpendicular to the first guide direction D5and the axial direction D1.

The guide device76includes a first guide pole91, a second guide pole92, and a biasing element93. The first guide pole91and the second guide pole92extend in the second guide direction D6to guide the tensioner90in the second guide direction D6. The biasing element93is configured to bias the tensioner90along the first guide pole91and the second guide pole92in the second guide direction D6. The biasing element93is configured to pull the tensioner90toward the guide member78in the second guide direction D6. While the biasing element93is a tension spring in the illustrated embodiment, the biasing element93can be members other than the tension spring. The tensioner90is a pulley, for example.

As seen inFIG. 13, the tensioner90moves integrally with the guide member78relative to the base member18(FIG. 4) in the first guide direction D5. The tensioner90is configured to guide the first coupling member24together with the guide member78.

As seen inFIG. 4, the base member18is configured to store lubricant in the internal space26. The base member18includes a supply port94through which the lubricant is to be supplied to the internal space26. Furthermore, the bicycle transmission apparatus12comprises a lubricant supply device95configured to apply lubricant to the first coupling member24. The lubricant supply device95is attached to the guide member78to move integrally with the guide member78.

As seen inFIG. 14, the lubricant supply device95includes a lubricant case96and a brush98. The lubricant case96is configured to store the lubricant. The brush98is mounted to the lubricant case96to be in contact with the lubricant stored in the lubricant case96. The brush98is disposed to be in contact with the first coupling member24. The lubricant is applied to the first coupling member24via the brush98.

As seen inFIG. 4, the bicycle transmission apparatus12comprises an additional lubricant supply device100configured to supply lubricant the input coupling member30. The additional lubricant supply device100is attached to the base member18. Since the additional lubricant supply device100has the same construction as the construction of the lubricant supply device95illustrated inFIG. 14, it will not be described and/or illustrated in detail here for the sake of brevity.

As seen inFIG. 15, the guide device76is configured to move and position the guide member78between first to seventh guide positions P11to P17in the first guide direction D5. The first to seventh guide positions P11to P17respectively correspond to the second cogwheels CW27to CW21.

As seen inFIGS. 15 and 16, the first transmission member20is movable relative to the base member18and the first coupling member24in the first axial direction D11without changing an axial relative position between the first coupling member24and the second transmission member22during one of upshifting and downshifting. In the illustrated embodiment, the first transmission member20is movable relative to the base member18and the first coupling member24in the first axial direction D11without changing an axial relative position between the first coupling member24and the second transmission member22during the upshifting. Furthermore, the first transmission member20is movable relative to the base member18and the first coupling member24in the second axial direction D12without changing the axial relative position between the first coupling member24and the second transmission member22during the downshifting.

As seen inFIGS. 16 and 17, the first transmission member20is movable together with the first coupling member24relative to the base member18in the second axial direction D12so as to change the axial relative position between the first coupling member24and the second transmission member22during another of the upshifting and the downshifting. In the illustrated embodiment, the first transmission member20is movable together with the first coupling member24relative to the base member18in the second axial direction D12so as to change the axial relative position between the first coupling member24and the second transmission member22during the upshifting. Furthermore, the first transmission member20is movable together with the first coupling member24relative to the base member18in the first axial direction D11so as to change the axial relative position between the first coupling member24and the second transmission member22during the downshifting.

As seen inFIG. 18, the bicycle transmission apparatus12further comprises a transmission controller102. The transmission controller102is configured to control the switching device66and the guide device76. Specifically, the transmission controller102is configured to control the switching actuator68and the guide actuator86. In the illustrated embodiment, the transmission controller102is constituted as a microcomputer and includes a processor104and a memory106. The processor104includes a central processing unit (CPU). The memory106includes a read only memory (ROM) and a random access memory (RAM). For example, a program stored in the memory106is read into the processor104, and thereby several functions of the transmission controller102are performed. The transmission controller102, the switching device66and the guide device76are powered by a battery (e.g. a rechargeable battery) which is mounted on the bicycle frame13or the base member18.

While the functions of the transmission controller102are performed by software, the functions of the transmission controller102can be performed by hardware or by a combination of the software and the hardware if needed and/or desired.

The transmission controller102is configured to store a transmission route RT1(FIG. 19) in the memory106.FIG. 19shows a total number of the first teeth42in each of the first cogwheels CW11to CW17, a total number of the second teeth44in each of the second cogwheels CW21to CW27, and gear ratios defined the first cogwheels CW11to CW17and the second cogwheels CW21to CW27. The transmission route RT1is defined by thirteen gear ratios among the gear ratios defined by the first cogwheels CW11to CW17and the second cogwheels CW21to CW27. Namely, the transmission controller102includes a transmission route memory configured to store the transmission route RT1defined by at least two of the gear ratios defined by the first cogwheels CW11to CW17and the second cogwheels CW21to CW27.

To control the switching device66and the guide device76based on the transmission route RT1ofFIG. 19, as seen inFIGS. 18 and 20, the transmission controller102is configured to store shift information SF1defined based on the transmission route RT1in the memory106. As seen inFIG. 20, for example, the shift information SF1includes combinations of the axial positions of the first transmission member20and the positions of the guide member78for the speed stages of the bicycle transmission apparatus12. The transmission controller102is further configured to store a current speed stage of the bicycle transmission apparatus12in the memory106.

As seen inFIG. 18, the switching device66includes a first motor driver108and a first position sensor110. The first motor driver108is configured to control the switching actuator68based on commands and/or signals from the transmission controller102. The first position sensor110is configured to sense the axial position of the first transmission member20. In the illustrated embodiment, the first position sensor110is configured to sense one of a rotational position of the switching actuator68, a rotational position of the reduction structure72, and a rotational position of the first shaft33to obtain the axial position of the first transmission member20. While the first position sensor110is a potentiometer in the illustrated embodiment, the first position sensor110can be other sensors such as a rotary encoder if needed and/or desired. The transmission controller102is configured to store a current axial position of the first transmission member20among the first axial position P1and the second axial position P2in the memory106. Namely, the transmission controller102includes a first position memory configured to store the current axial position of the first transmission member20.

The guide device76includes a second motor driver112and a second position sensor114. The second motor driver112is configured to control the guide actuator86based on commands and/or signals from the transmission controller102. The second position sensor114is configured to sense the position of the guide member78. In the illustrated embodiment, the second position sensor114is configured to sense a rotational position of the guide actuator86, a rotational position of the intermediate gear88, and a rotational position of the guide shaft82to obtain the position of the guide member78. While the second position sensor114is a potentiometer in the illustrated embodiment, the second position sensor114can be other sensors such as a rotary encoder. The transmission controller102is configured to store a current position of the guide member78in the memory106. Namely, the transmission controller102includes a second position memory configured to store the current position of the guide member78.

The shifter14includes a first operating member SR1and a second operating member SR2. The first operating member SR1is configured to be operated by a user for upshifting. The second operating member SR2is configured to be operated by the user for downshifting. The shifter14includes a signal controller116configured to generate a shifting signal SS based on input operations of the first operating member SR1and the second operating member SR2. The signal controller116is configured to generate an upshifting signal USS based on an input operation of the first operating member SR1. The signal controller116is configured to generate a downshifting signal DSS based on an input operation of the second operating member SR2. The upshifting signal USS and the downshifting signal DSS are inputted from the shifter14to the transmission controller102. The transmission controller102controls the switching actuator68and the guide actuator86based on the shifting signal SS and the transmission route RT1(e.g., the shift information SF1) stored in the memory106.

For example, when the upshifting signal USS is inputted from the shifter14to the transmission controller102in a state where the speed stage is in a low gear (FIG. 15), the transmission controller102controls the switching actuator68to move the first transmission member20from the first axial position P1to the second axial position P2in the first axial direction D11(FIGS. 16 and 20). At this time, as seen inFIGS. 16 and 20, the transmission controller102controls the guide actuator86to keep the guide member78at the first guide position P11. Thus, the first transmission member20is shifted relative to the second transmission member22and the first coupling member24in the first axial direction D11. Accordingly, as seen inFIGS. 16, 19, and 20, the first coupling member24is shifted from the first cogwheel CW11to the first cogwheel CW12, changing the speed stage of the bicycle transmission apparatus12from low gear to second gear.

When the upshifting signal USS is inputted from the shifter14to the transmission controller102in a state where the speed stage is in second gear (FIG. 16), the transmission controller102controls the switching actuator68to move the first transmission member20from the second axial position P2to the first axial position P1in the second axial direction D12(FIGS. 17 and 20). At this time, as seen inFIGS. 17 and 20, the transmission controller102controls the guide actuator86to move the guide member78from the first guide position P11to the second guide position P12. In the illustrated embodiment, the first transmission member20and the guide member78are substantially simultaneously moved. Thus, the first transmission member20and the first coupling member.24are shifted relative to the second transmission member22in the second axial direction D12. Accordingly, as seen inFIGS. 17, 19, and 20, the first coupling member24is shifted from the second cogwheel CW27to the second cogwheel CW26, changing the speed stage of the bicycle transmission apparatus12from second gear to third gear.

When the downshifting signal DSS is inputted from the shifter14to the transmission controller102in a state where the speed stage is in third gear (FIG. 17), the transmission controller102controls the switching actuator68to move the first transmission member20from the first axial position P1to the second axial position P2in the first axial direction D11(FIGS. 16 and 20). At this time, as seen inFIGS. 16 and 20, the transmission controller102controls the guide actuator86to move the guide member78from the second guide position P12to the first guide position P11. Thus, the first transmission member20and the first coupling member24are shifted relative to the second transmission member22in the first axial direction D11. Accordingly, as seen inFIGS. 16, 19, and 20, the first coupling member24is shifted from the second cogwheel CW26to the second cogwheel CW27, changing the speed stage of the bicycle transmission apparatus12from third gear to second gear.

When the downshifting signal DSS is inputted from the shifter14to the transmission controller102in a state where the speed stage is in second gear (FIG. 16), the transmission controller102controls the switching actuator68to move the first transmission member20from the second axial position P2to the first axial position P1in the second axial direction D12(FIGS. 15 and 20). At this time, as seen inFIGS. 15 and 20, the transmission controller102controls the guide actuator86to keep the guide member78at the first guide position P11. Thus, the first transmission member20is shifted relative to the second transmission member22and the first coupling member24in the second axial direction D12. Accordingly, as seen inFIGS. 15, 19, and 20, the first coupling member24is shifted from the first cogwheel CW12to the first cogwheel CW11, changing the speed stage of the bicycle transmission apparatus12from second gear to low gear.

As described above, since the transmission controller102controls the switching device66and the guide device76between low gear and thirteenth gear based on the transmission route RT1shown inFIG. 19(e.g., the shift information SF1shown inFIG. 20), they will not be described and/or illustrated in detail here for the sake of brevity. If the transmission controller102and the shifter14are communicated by wireless technology, the transmission controller102and the shifter14respectively have wireless communication devices, and the shifter14has another battery.

Furthermore, the transmission controller102is configured to change an operating speed of each of the switching device66and the guide device76based on input information. Specifically, as seen inFIG. 21, the transmission controller102is configured to determine at a determination interval T0whether the shifting signal SS is continuous. The transmission controller102is configured to output shifting commands to the switching device66and the guide device76at the determination interval T0if the transmission controller102determines at the determination interval T0that the shifting signal SS is continuous. Namely, the transmission controller102includes a determination part configured to determine at the determination interval T0whether the shifting signal SS is continuous. Furthermore, the transmission controller102includes a command generator configured to output a shifting command to each of the switching device66and the guide device76at the determination interval T0if the transmission controller102determines at the determination interval T0that the shifting signal SS is continuous.

As seen inFIG. 21, the switching device66and the guide device76are configured to change a current speed stage by one stage based on the shifting commands from the transmission controller102. In a case where the signal duration SD of the shifting signal SS is longer than the determination interval T0, the transmission controller102outputs a plurality of shifting commands to each of the switching device66and the guide device76in accordance with the signal duration SD.

As seen inFIG. 21, for example, in a case where the signal duration SD of the shifting signal SS has a length more than three times longer than the determination interval T0, the transmission controller102controls the switching device66and the guide device76to continuously change the current speed stage by four stages based on the shifting signal SS and the signal duration SD.

More specifically, in a case where the switching device66and the guide device76upshift the current speed stage from low gear, the transmission controller102outputs an upshifting command to the switching device66and the guide device76when the shifting signal SS is inputted from the shifter14to the transmission controller102. The switching device66and the guide device76changes the current speed stage from the low gear to a second gear in response to the upshifting command from the transmission controller102.

As seen inFIG. 21, when the transmission controller102determines at the determination interval T0that the shifting signal SS is continuous, the transmission controller102outputs an additional upshifting command to the switching device66and the guide device76. The switching device66and the guide device76change the current speed stage from the second gear to a third gear in response to the additional upshifting command.

When the transmission controller102determines at the next determination interval T0that the shifting signal SS is still continuous, the transmission controller102outputs an additional upshifting command to the switching device66and the guide device76. The switching device66and the guide device76change the current speed stage from the third gear to a fourth gear in response to the additional upshifting command. The above operation is applied to the upshifting from the fourth gear to a fifth gear.

When the transmission controller102determines at the next determination interval T0that the shifting signal SS is not continuous (that the shifting signal SS has been terminated), the transmission controller102does not output an additional upshifting command to the switching device66and the guide device76.

As seen inFIG. 18, the bicycle transmission apparatus12further comprises a sensing device118configured to sense a pedaling state of the bicycle10. The transmission controller102is configured to control the switching device66to change a timing at which the first transmission member20moves relative to the base member18based on the pedaling state sensed by the sensing device118. The transmission controller102is configured to control the guide actuator86to change a timing at which the guide member78moves relative to the base member18based on the pedaling state sensed by the sensing device118.

The transmission controller102is configured to change an operating speed of each of the switching actuator68and the guide actuator86based on input information. The sensing device118is configured to sense the pedaling state of the bicycle10as the input information. The transmission controller102is configured to change the operating speed of each of the switching actuator68and the guide actuator86based on the pedaling state sensed by the sensing device118. Namely, the transmission controller102includes a speed changing part configured to change the operating speed of each of the switching actuator68and the guide actuator86based on the input information.

As seen inFIG. 18, the sensing device118comprises a cadence sensor120configured to sense a cadence of the bicycle10as the pedaling state of the bicycle10. The cadence sensor120is attached to the bicycle frame B3(FIG. 1), for example. The cadence sensor120is configured to sense a rotational speed of the crank arm B71of the bicycle crank B7as the cadence. For example, the cadence sensor120is configured to detect a detected member such as a magnet attached to the crank arm B71.

The transmission controller102is configured to change one of the operating speed and the response speed based on the pedaling state sensed by the sensing device118. In the illustrated embodiment, the transmission controller102is configured to change the operating speed of each of the switching actuator68and the guide actuator86based on the cadence Cs sensed by the cadence sensor120.

The transmission controller102decreases the operating speed of each of the switching actuator68and the guide actuator86if the cadence Cs sensed by the cadence sensor120is lower than a cadence threshold. The transmission controller102increases the operating speed of each of the switching actuator68and the guide actuator86if the cadence Cs sensed by the cadence sensor120is equal to or higher than the cadence threshold.

As seen inFIG. 18, the transmission controller102configured to store the cadence threshold and a plurality of predetermined operating speeds in the memory106. Namely, the transmission controller102includes a cadence-threshold memory configured to store the cadence threshold, and an operating-speed memory is configured to store the plurality of predetermined operating speeds.

The transmission controller102is configured to select, as the operating speed, one of the predetermined operating speeds in accordance with the cadence Cs sensed by the cadence sensor120. Namely, the transmission controller102includes an operating-speed selector configured to select, as the operating speed, one of the predetermined operating speeds in accordance with the cadence Cs sensed by the cadence sensor120. The transmission controller102is configured to control the switching actuator68and the guide actuator86to change the speed stage with the selected operating speed. More specifically, the transmission controller102is configured to output the selected operating speed as an operating speed command to each of the switching actuator68and the guide actuator86. The first motor driver108is configured to control the switching actuator68to move the first transmission member20with the selected operating speed. The second motor driver112is configured to control the guide actuator86to move the guide member78with the selected operating speed.

In the illustrated embodiment, the transmission controller102is configured to select one of the predetermined operating speeds as the operating speed in accordance with the cadence Cs. However, the transmission controller102can be configured to continuously change the operating speed in accordance with the cadence Cs if needed and/or desired.

As seen inFIG. 22, for example, the transmission controller102is configured to store a first operating speed V1and a second operating speed V2different from the first operating speed V1for the operating speed of the switching actuator68. In the illustrated embodiment, the second operating speed V2is lower than the first operating speed V1. For example, the first operating speed V1is a normal operating speed of the switching actuator68. The transmission controller102can be configured to store more than three operating speeds for the switching actuator68if needed and/or desired.

Similarly, the transmission controller102is configured to store a third operating speed V3and a fourth operating speed V4different from the third operating speed V3for the operating speed of the guide actuator86. In the illustrated embodiment, the fourth operating speed V4is lower than the third operating speed V3. For example, the third operating speed V3is a normal operating speed of the guide actuator86. The transmission controller102can be configured to store more than three operating speeds for the guide actuator86if needed and/or desired.

As seen inFIG. 23, the transmission controller102is configured to select the first operating speed V1as the operating speed from among the first operating speed V1and the second operating speed V2if the cadence Cs sensed by the cadence sensor120is equal to or higher than the cadence threshold Cth. Similarly, the transmission controller102is configured to select the third operating speed V3as the operating speed from among the third operating speed V3and the fourth operating speed V4if the cadence Cs sensed by the cadence sensor120is equal to or higher than the cadence threshold Cth. The transmission controller102controls the switching actuator68and the guide actuator86to change a current speed stage with the first operating speed V1and the third operating speed V3. More specifically, the first motor driver108controls the switching actuator68to move the first transmission member20with the first operating speed V1inputted from the transmission controller102. The second motor driver112controls the guide actuator86to move the guide member78with the third operating speed V3inputted from the transmission controller102.

As seen inFIG. 23, the transmission controller102is configured to select the second operating speed V2as the operating speed from among the first operating speed V1and the second operating speed V2if the cadence Cs sensed by the cadence sensor120is lower than the cadence threshold Cth. The transmission controller102is configured to select the fourth operating speed V4as the operating speed from among the third operating speed V3and the fourth operating speed V4if the cadence Cs sensed by the cadence sensor120is lower than the cadence threshold Cth. The transmission controller102controls the switching actuator68and the guide actuator86to change a current speed stage with the second operating speed V2and the fourth operating speed V4. More specifically, the first motor driver108controls the switching actuator68to move the first transmission member20with the second operating speed V2inputted from the transmission controller102. The second motor driver112controls the guide actuator86to move the guide member78with the fourth operating speed V4inputted from the transmission controller102.

Instead of changing the operating speed, the transmission controller102can be configured to change the response speed of each of the switching device66and the guide device76. Furthermore, the function for changing the operating speed can be omitted from the transmission controller102if needed and/or desired.

With the bicycle transmission apparatus12, the first coupling member24is configured to couple the first transmission member20to the second transmission member22to transmit rotation of the first transmission member20to the second transmission member22at the variable speed stage. The first transmission member20is movable relative to the base member18in the axial direction D1. The variable speed stage is variable in accordance with at least one positional relationship among the first transmission member20, the second transmission member22, and the first coupling member24in the axial direction D1. Accordingly, it is possible to change a speed stage of the bicycle transmission apparatus12by moving the first transmission member20in the axial direction D1.

Furthermore, since the base member18is configured to be attached to the bicycle frame B3as a separate member from the bicycle frame B3, it is possible to treat the bicycle transmission apparatus12as a single unit. This makes centering of the input shaft28, the first transmission member20, and the second transmission member22easier.

Second Embodiment

A bicycle transmission apparatus212in accordance with a second embodiment will be described below referring toFIG. 24. The bicycle transmission apparatus212has the same configuration as the bicycle transmission apparatus12except for the first angle AG11. Thus, elements having substantially the same function as those in the first embodiment will be numbered the same here, and will not be described and/or illustrated again in detail here for the sake of brevity.

As seen inFIG. 24, in the bicycle transmission apparatus212, a first angle AG21is defined about the first rotational axis A1between a first line segment L21connecting the input rotational axis A3and the first rotational axis A1and a second line segment L22connecting the first rotational axis A1and the second rotational axis A2when viewed from the axial direction D1. A second angle AG22is defined about the first rotational axis A1between the first line segment L21and the second line segment L22when viewed from the axial direction D1. The second angle AG22is defined on an opposite side of the first angle AG21relative to the first rotational axis A1when viewed from the axial direction D1. The first angle AG21is smaller than the second angle AG22and is an acute angle. The first angle AG21is smaller than 90 degrees and larger than 0 degree.

With the bicycle transmission apparatus212, it is possible to obtain substantially the same advantageous effect as that of the bicycle transmission apparatus12in accordance with the first embodiment.

Third Embodiment

A bicycle310equipped with a bicycle transmission apparatus312in accordance with a third embodiment will be described below referring toFIGS. 25 and 26. The bicycle transmission apparatus312has the same configuration as the bicycle transmission apparatus12except for the output shaft36. Thus, elements having substantially the same function as those in the above embodiments will be numbered the same here, and will not be described and/or illustrated again in detail here for the sake of brevity.

As seen inFIG. 25, in the bicycle transmission apparatus312, the pivot axis PA1coincides with the second rotational axis A2. Specifically, as seen inFIG. 26, the bicycle transmission apparatus312comprises an output shaft336rotatable relative to the base member18about the second rotational axis A2. The output shaft336is coupled to the second transmission member22to transmit rotation of the second transmission member22to a bicycle wheel (e.g., the rear wheel B62) rotatable relative to the second frame B32. The output shaft336is configured to extend through a pivot opening B36of the bicycle frame B3along the second rotational axis A2. In the illustrated embodiment, the first sub frame B311of the first frame B31includes the pivot opening B36.

As seen inFIG. 26, the bicycle transmission apparatus312further comprises an inner bearing unit313. The inner bearing unit313is configured to be provided in the pivot opening B36of the bicycle frame B3. The inner bearing unit313is configured to rotatably couple the output shaft336to the bicycle frame B3about the second rotational axis A2via an outer bearing unit315provided radially outward of the inner bearing unit313. The outer bearing unit315is configured to pivotably couple the second frame B32to the first frame B31about the second rotational axis A2.

The base member18includes a first tubular support319aand a second tubular support319b. The first tubular support319ais secured to the base member body18aand extends from the base member body18aalong the second rotational axis A2. The second tubular support319bis secured to the base member body18aand extends from the base member body18aalong the second rotational axis A2. The second tubular support319bis provided on an opposite side of the first tubular support319arelative to the base member body18a. The output shaft336extends through a through-hole of the first tubular support319a. The first tubular support319aextends through the pivot opening B36. The second tubular support319bextends through an additional pivot opening B37of the bicycle frame B3. In the illustrated embodiment, the first sub frame B312of the first frame B31includes the additional pivot opening B37.

As seen inFIG. 26, the first sub frame B311includes a third tubular support B311a, and the first sub frame B312includes a fourth tubular support B312a. The third tubular support B311ais attached to an outer periphery of the first tubular support319aand includes the pivot opening B36. The fourth tubular support B312ais attached to the second tubular support319band includes the additional pivot opening B37.

The base member body18ais mounted to the first sub frames B311and B312of the first frame B31via the first tubular support319aand the second tubular support319b. The third tubular support B311ais rotatably mounted to the second sub frame B321via the outer bearing unit315. The fourth tubular support B312ais rotatably mounted to the second sub frame B322via an additional outer bearing unit317. Namely, the second sub frames B321and B322are pivotably mounted to the first frame B31via the outer bearing unit315and the additional outer bearing unit317.

With the bicycle transmission apparatus312, it is possible to constantly keep a distance between the output cogwheel38and the rear sprocket B9, preventing the output coupling member40from be loosen.

Fourth Embodiment

A bicycle410equipped with a bicycle transmission apparatus412in accordance with a fourth embodiment will be described below referring toFIGS. 27 and 28. The bicycle transmission apparatus412has the same configuration as the bicycle transmission apparatus12except for the electric-assisted configuration. Thus, elements having substantially the same function as those in the above embodiments will be numbered the same here, and will not be described and/or illustrated again in detail here for the sake of brevity.

As seen inFIG. 27, the bicycle transmission apparatus412further comprises an assist device451configured to assist pedaling. The assist device451is configured to generate an assist torque inputted to the second transmission member22to assist pedaling. The assist device451is provided on a front side of the base member18in an attachment state where the bicycle transmission apparatus412is attached to the bicycle frame B3. In the illustrated embodiment, the assist device451comprises an assist motor such as a direct-current (DC) motor and a reduction gear unit.

The bicycle transmission apparatus412further comprises an electrical power source453configured to supply electrical power to the assist device451. The electrical power source453is provided under the base member18in the attachment state of the bicycle transmission apparatus412. In the illustrated embodiment, the electrical power source453comprises a rechargeable battery, for example.

As seen inFIG. 28, the bicycle transmission apparatus412further comprises a sensing device418and an assist controller455. The sensing device418is configured to sense a pedaling state of the bicycle10. In the illustrated embodiment, the sensing device418comprises a torque sensor421configured to sense a pedaling torque applied to the bicycle crank B7(FIG. 27). The assist controller455is configured to control the assist device451to input the assist torque to the second transmission member22based on the pedaling state sensed by the sensing device418. The assist controller455is configured to control the assist device451to input the assist torque to the second transmission member22based on the pedaling torque sensed by the sensing device418.

In the illustrated embodiment, the assist controller455is constituted as a microcomputer and includes a processor404and a memory406. The processor404includes a CPU. The memory406includes a ROM and a RAM. For example, a program stored in the memory406is read into the processor404, and thereby several functions of the assist controller455are performed.

The pedaling torque is inputted from the sensing device418into the transmission controller102instead of the cadence sensed by the sensing device118in accordance with the first embodiment, for example. The pedaling torque sensed by the torque sensor421can be used for changing the operation speed of each of the switching device66and the guide device76. The transmission controller102decreases the operating speed of each of the switching actuator68and the guide actuator86if the pedaling torque sensed by the torque sensor421is higher than a toque threshold. The transmission controller102increases the operating speed of each of the switching actuator68and the guide actuator86if the pedaling torque sensed by the torque sensor421is equal to or lower than the torque threshold.

While the assist device451is configured to transmit the assist torque to the output shaft36(FIG. 27) in the illustrated embodiment, the assist device451can be configured to transmit the assist torque members other than the output shaft36.

As described above, it is possible to apply the assist device451to the bicycle transmission apparatus12in accordance with the first embodiment.

It will be apparent to those skilled in the bicycle field from the present disclosure that the constructions of the above embodiments can be at least partially combined with each other.

The term “configured” as used herein to describe a component, section or part of a device includes hardware and/or software that is constructed and/or programmed to carry out the desired function. The desired function can be carried out by hardware, software, or a combination of hardware and software.