Bicycle operating device

A bicycle operating device comprises a base, an operating member, a hydraulic cylinder, a piston, a connecting link, and a guiding structure. The operating member is pivotally coupled to the base. The hydraulic cylinder is mounted to the base. The piston is movably provided in the hydraulic cylinder. The connecting link is pivotally coupled to each of the operating member and the piston to move the piston relative to the hydraulic cylinder in response to a pivotal movement of the operating member relative to the base. The guiding structure is coupled to the piston to guide the piston relative to the base.

BACKGROUND OF THE INVENTION

Field of the Invention

The present invention relates to a bicycle operating device.

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 an operating device.

SUMMARY OF THE INVENTION

In accordance with a first aspect of the present invention, a bicycle operating device comprises a base, an operating member, a hydraulic cylinder, a piston, a connecting link, and a guiding structure. The operating member is pivotally coupled to the base. The hydraulic cylinder is mounted to the base. The piston is movably provided in the hydraulic cylinder. The connecting link is pivotally coupled to each of the operating member and the piston to move the piston relative to the hydraulic cylinder in response to a pivotal movement of the operating member relative to the base. The guiding structure is coupled to the piston to guide the piston relative to the base.

With the bicycle operating device according to the first aspect, it is possible to change an amount of movement of the piston relative to an amount of movement of the operating member by changing a shape, a position, and/or a size of the connecting link. Thus, it is possible to obtain a preferable movement ratio characteristic between the operating member and the piston.

In accordance with a second aspect of the present invention, the bicycle operating device according to the first aspect is configured so that the operating member is pivotally coupled to the base about a first pivot axis. The connecting link is pivotally coupled to the operating member about a second pivot axis spaced apart from the first pivot axis. The connecting link is pivotally coupled to the piston about a third pivot axis spaced apart from the first and second pivot axes.

With the bicycle operating device according to the second aspect, it is possible to smoothly transmit the pivotal movement of the operating member to the piston.

In accordance with a third aspect of the present invention, the bicycle operating device according to the second aspect is configured so that the first, second and third pivot axes are parallel to each other.

With the bicycle operating device according to the third aspect, it is possible to more smoothly transmit the pivotal movement of the operating member to the piston.

In accordance with a fourth aspect of the present invention, the bicycle operating device according to the second or third aspect is configured so that the piston is movable relative to the hydraulic cylinder in a movement direction between an initial position and an actuated position. The second pivot axis is disposed between the first and third pivot axes in a perpendicular direction which is perpendicular to the movement direction.

With the bicycle operating device according to the fourth aspect, it is possible to shorten a size of the connecting link, allowing the bicycle operating device to be more compact.

In accordance with a fifth aspect of the present invention, the bicycle operating device according to the fourth aspect is configured so that the hydraulic cylinder includes a cylinder bore in which the piston is at least partially provided. The piston and the cylinder bore define a hydraulic chamber between the piston and the cylinder bore. The third pivot axis is disposed between the second pivot axis and the hydraulic chamber in the movement direction, at least in an initial state where the piston is positioned at the initial position.

With the bicycle operating device according to the fifth aspect, it is possible to transmit a pushing force from the operating member to the piston via the connecting link.

In accordance with a sixth aspect of the present invention, the bicycle operating device according to the fifth aspect is configured so that the second pivot axis is disposed at a position which is equal to a position of the first pivot axis in the movement direction or which is located between the third pivot axis and the first pivot axis in the movement direction, at least in the initial state.

With the bicycle operating device according to the sixth aspect, it is possible to quickly change the hydraulic pressure around a starting point of the second pivot axis corresponding to the initial position of the piston.

In accordance with a seventh aspect of the present invention, the bicycle operating device according to any one of the fourth to sixth aspects is configured so that the hydraulic cylinder includes a cylinder bore in which the piston is at least partially provided. The piston and the cylinder bore define a hydraulic chamber between the piston and the cylinder bore. The second pivot axis is disposed between the third pivot axis and the hydraulic chamber in the movement direction, at least in an initial state where the piston is positioned at the initial position.

With the bicycle operating device according to the seventh aspect, it is possible to transmit a pulling force from the operating member to the piston via the connecting link.

In accordance with an eighth aspect of the present invention, the bicycle operating device according to the seventh aspect is configured so that the second pivot axis is disposed at a position which is equal to a position of the first pivot axis in the movement direction or which is located between the third pivot axis and the first pivot axis in the movement direction, at least in the initial state.

With the bicycle operating device according to the eighth aspect, it is possible to quickly change the hydraulic pressure around a starting point of the second pivot axis corresponding to the initial position of the piston.

In accordance with a ninth aspect of the present invention, the bicycle operating device according to any one of the second to eighth aspects is configured so that the guiding structure includes a guiding link. The guiding link is pivotally coupled to the piston about a fourth pivot axis. The guiding link is pivotally coupled to the base about a fifth pivot axis.

With the bicycle operating device according to the ninth aspect, it is possible to make a movement of the piston relative to the base member more stable because of the guiding link.

In accordance with a tenth aspect of the present invention, the bicycle operating device according to the ninth aspect is configured so that the fourth pivot axis coincides with the third pivot axis.

With the bicycle operating device according to the tenth aspect, it is possible to simplify a connecting part provided among the piston, the connecting link, and the guiding link.

In accordance with an eleventh aspect of the present invention, the bicycle operating device according to any one of the second to tenth aspects is configured so that the connecting link includes a first proximal end and a first distal end. The first proximal end is pivotally coupled to the operating member about the second pivot axis. The first distal end is pivotally coupled to the piston about the third pivot axis.

With the bicycle operating device according to the eleventh aspect, it is possible to simplify the structure of the connecting link.

In accordance with a twelfth aspect of the present invention, the bicycle operating device according to the eleventh aspect is configured so that the guiding structure includes a guiding link. The guiding link has a second proximal end and a second distal end. The second proximal end is pivotally coupled to the piston about a fourth pivot axis. The second distal end is pivotally coupled to the base about a fifth pivot axis.

With the bicycle operating device according to the twelfth aspect, it is possible to guide the piston with a simple structure.

In accordance with a thirteenth aspect of the present invention, the bicycle operating device according to any one of the first to twelfth aspects is configured so that the hydraulic cylinder includes a cylinder bore. The piston includes a piston body and a piston rod. The piston body is movably provided in the cylinder bore. The piston rod is pivotally coupled to the piston body to operatively couple the connecting link to the piston body.

With the bicycle operating device according to the thirteenth aspect, it is possible to simplify the structure of the piston body.

In accordance with a fourteenth aspect of the present invention, the bicycle operating device according to the thirteenth aspect is configured so that the operating member is pivotally coupled to the base about a first pivot axis. The connecting link is pivotally coupled to the operating member about a second pivot axis spaced apart from the first pivot axis. The connecting link is pivotally coupled to the piston rod about a third pivot axis spaced apart from the first and second pivot axes.

With the bicycle operating device according to the fourteenth aspect, it is possible to smoothly transmit the pivotal movement of the operating member to the piston with simplifying the structure of the connecting link.

In accordance with a fifteenth aspect of the present invention, the bicycle operating device according to the fourteenth aspect is configured so that the guiding structure includes a guiding link. The guiding link is pivotally coupled to the piston rod about a fourth pivot axis. The guiding link is pivotally coupled to the base about a fifth pivot axis.

With the bicycle operating device according to the fifteenth aspect, it is possible to make a movement of the piston relative to the base more stable because of the guiding link.

In accordance with a sixteenth aspect of the present invention, the bicycle operating device according to the fifteenth aspect is configured so that the fourth pivot axis coincides with the third pivot axis.

With the bicycle operating device according to the sixteenth aspect, it is possible to simplify a connecting part provided among the piston rod, the connecting link, and the guiding link.

In accordance with a seventeenth aspect of the present invention, the bicycle operating device according to any one of the second to sixteenth aspects is configured so that the guiding structure includes a guiding bore through which the piston extends. The piston and the cylinder bore define a hydraulic chamber between the piston and the cylinder bore. The guiding bore is provided on the base between the hydraulic chamber and a third pivot axis.

With the bicycle operating device according to the seventeenth aspect, it is possible to make a movement of the piston relative to the base more stable because of the guiding bore.

In accordance with an eighteenth aspect of the present invention, the bicycle operating device according to any one of the first to seventeenth aspects further comprises a hydraulic reservoir. The hydraulic cylinder includes a cylinder bore. The piston is movably provided in the cylinder bore. The hydraulic reservoir is connected to a hydraulic chamber defined by the piston and the hydraulic cylinder in the cylinder bore.

With the bicycle operating device according to the eighteenth aspect, the hydraulic reservoir can absorb change in volume of hydraulic fluid caused by change in a temperature of the hydraulic fluid.

DESCRIPTION OF THE EMBODIMENTS

First Embodiment

Referring initially toFIG. 1, a bicycle operating device10in accordance with a first embodiment is illustrated. The bicycle operating device10is connected to a bicycle component B1via a hydraulic hose B2. Examples of the bicycle component B1include a bicycle brake caliper. The bicycle operating device10comprises a base12and an operating member14. The operating member14is pivotally coupled to the base12. The base12is coupled to a bicycle tubular part B3such as a handlebar in a mounting state where the bicycle operating device10is mounted to the bicycle tubular part B3. The bicycle tubular part B3includes a center axis CA0. In this embodiment, the base12includes a base body16and a clamp structure18. The operating member14is pivotally coupled to the base body16. The clamp structure18couples the base body16to the bicycle tubular part B3.

While the base body16is integrally provided with the clamp structure18in this embodiment, the base body16can be a separate part from the clamp structure18. In this embodiment, the bicycle operating device10is a right-side operating device operated by a rider's right hand. However, structures of the bicycle operating device10can be applied to a left-side operating device operated by a rider's left hand.

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 a saddle (not shown) of a bicycle with facing the handlebar. Accordingly, these terms, as utilized to describe the bicycle operating device10, should be interpreted relative to the bicycle equipped with the bicycle operating device10as used in an upright riding position on a horizontal surface.

As seen inFIG. 2, the operating member14is pivotable relative to the base12between a rest position P11and an operated position P12. The operating member14includes a first end part20and a second end part22opposite to the first end part20. The operating member14extends between the first end part20and the second end part22. The first end part20is pivotally coupled to the base12. In this embodiment, the rest position P11and the operated position P12are defined based on the first end part20and the second end part22.

In the present application, the term “rest position” as used herein refers to a position at which a movable part such as the operating member14remains stationary in a state where the movable part is not operated by the user. The term “operated position” as used herein refers to a position at which the movable part has been operated by the user to perform the operation of the bicycle component B1.

As seen inFIG. 2, the bicycle operating device10comprises a hydraulic cylinder24and a piston26. The hydraulic cylinder24is mounted to the base12. The piston26is movably provided in the hydraulic cylinder24. The piston26is movable relative to the hydraulic cylinder24in a movement direction D1between an initial position P21and an actuated position P22. The initial position P21of the piston26corresponds to the rest position P11of the operating member14. The actuated position P22of the piston26corresponds to the operated position P12of the operating member14.

The hydraulic cylinder24includes a cylinder bore28in which the piston26is at least partially provided. The cylinder bore28defines a center axis CA1extending in the movement direction D1. The center axis CA1of the cylinder bore28extends along the center axis CA0of the bicycle tubular part B3in the mounting state where the bicycle operating device10is mounted to the bicycle tubular part B3. The piston26and the cylinder bore28define a hydraulic chamber C1between the piston26and the cylinder bore28. The hydraulic chamber C1is connected to a slave chamber of the bicycle component B1via the hydraulic hose B2.

As seen inFIG. 3, the piston26includes a piston body30and a piston rod32. The piston body30is movably provided in the cylinder bore28. The piston rod32is pivotally coupled to the piston body30. The piston rod32includes a first rod end34and a second rod end36opposite to the first rod end34. The first rod end34is pivotally coupled to the piston26. The hydraulic cylinder24includes a through-hole37connected to the cylinder bore28. The piston rod32extends through the through-hole37. The through-hole37has an inner diameter larger than an outer diameter of the piston rod32to avoid interference between the hydraulic cylinder24and the piston rod32.

The bicycle operating device10comprises a connecting link38. The connecting link38is pivotally coupled to each of the operating member14and the piston26to move the piston26relative to the hydraulic cylinder24in response to a pivotal movement of the operating member14relative to the base12. The piston rod32is pivotally coupled to the piston body30to operatively couple the connecting link38to the piston body30.

The bicycle operating device10comprises a guiding structure40. The guiding structure40is coupled to the piston26to guide the piston26relative to the base12. In this embodiment, the guiding structure40includes a guiding link42. The guiding link42is coupled to the piston26to guide the piston26relative to the base12.

The operating member14is pivotally coupled to the base12about a first pivot axis PA1. The connecting link38is pivotally coupled to the operating member14about a second pivot axis PA2spaced apart from the first pivot axis PA1. The connecting link38is pivotally coupled to the piston26about a third pivot axis PA3spaced apart from the first and second pivot axes PA1and PA2. The guiding link42is pivotally coupled to the piston26about a fourth pivot axis PA4. The guiding link42is pivotally coupled to the base12about a fifth pivot axis PA5.

The bicycle operating device10comprises a first pivot pin44, a second pivot pin46, and a third pivot pin48. The operating member14is pivotally coupled to the base12about the first pivot axis PA1via the first pivot pin44. The connecting link38is pivotally coupled to the operating member14about the second pivot axis PA2via the second pivot pin46. The connecting link38is pivotally coupled to the piston26about the third pivot axis PA3via the third pivot pin48. The guiding link42is pivotally coupled to the piston26about the fourth pivot axis PA4via the third pivot pin48. The guiding structure40includes a guide pivot pin50. The guiding link42is pivotally coupled to the base12about the fifth pivot axis PA5via the guide pivot pin50.

The connecting link38is pivotally coupled to the piston rod32about the third pivot axis PA3spaced apart from the first and second pivot axes PA1and PA2. The connecting link38includes a first proximal end52and a first distal end54. The first proximal end52is pivotally coupled to the operating member14about the second pivot axis PA2. The first distal end54is pivotally coupled to the piston26about the third pivot axis PA3.

The guiding link42is pivotally coupled to the piston rod32about the fourth pivot axis PA4. The guiding link42includes a second proximal end56and a second distal end58. The second proximal end56is pivotally coupled to the piston26about the fourth pivot axis PA4. The second distal end58is pivotally coupled to the base12about the fifth pivot axis PA5.

While the first, second and third pivot axes PA1, PA2, and PA3are parallel to each other in this embodiment, at least one of the first, second and third pivot axes PA1, PA2, and PA3can be non-parallel to another. While the fourth pivot axis PA4coincides with the third pivot axis PA3in this embodiment, the fourth pivot axis PA4can be offset from the third pivot axis PA3.

The bicycle operating device10further comprises a return spring59. The return spring59is provided in the hydraulic chamber C1to bias the piston26toward the rest position P21.

The second pivot axis PA2is disposed between the first and third pivot axes PA1and PA3in a perpendicular direction D2which is perpendicular to the movement direction D1. The third pivot axis PA3is disposed between the second pivot axis PA2and the hydraulic chamber C1in the movement direction D1, at least in an initial state where the piston26is positioned at the initial position P21. In other words, the second pivot axis PA2is farther from the hydraulic chamber C1than the third pivot axis PA3in the movement direction D1, at least in the initial state.

The second pivot axis PA2is disposed at a position which is equal to a position of the first pivot axis PA1in the movement direction D1or which is located between the third pivot axis PA3and the first pivot axis PA1in the movement direction D1, at least in the initial state. In this embodiment, the second pivot axis PA2is disposed at a position closer to the third pivot axis PA3than the first pivot axis PA1in the movement direction D1in the initial state where the piston26is positioned at the initial position P21. However, the second pivot axis PA2can be disposed at the position equal to the position of the first pivot axis PA1in the movement direction D1in the initial state where the piston26is positioned at the initial position P21.

As seen inFIG. 4, the bicycle operating device10further comprises a hydraulic reservoir60. The hydraulic reservoir60is connected to the hydraulic chamber C1defined by the piston26and the hydraulic cylinder24in the cylinder bore28. In this embodiment, the hydraulic reservoir60is provided at the base12(e.g., the base body16). The hydraulic reservoir60includes a reservoir tank62, a flexible diaphragm64, and a cover66. The reservoir tank62is adjacent to the hydraulic cylinder24. The reservoir tank62includes a recess68. The flexible diaphragm64is provided in the recess68and is made of a flexible material such as rubber. The cover66is attached to the reservoir tank62via fasteners70. The reservoir tank62and the flexible diaphragm64define a reservoir chamber C2.

The hydraulic reservoir60includes connecting holes72. The reservoir chamber C2is connected to the hydraulic chamber C1via the connecting holes72in the initial state where the piston26is positioned at the initial position P21. The piston26covers the connecting holes72to interrupt connection between the reservoir chamber C2and the hydraulic chamber C1in an intermediate state where the piston26is positioned between an intermediate position P23and the actuated position P22. The intermediate position P23is defined between the initial position P21and the actuated position P22and is closer to the initial position P21than to the actuated position P22. While the hydraulic reservoir60includes the connecting holes72in this embodiment, the hydraulic reservoir60can include at least one connecting hole72.

As seen inFIGS. 5 to 7, when the operating member14is pivoted relative to the base12from the rest position P11toward the operated position P12, the pivotal movement of the operating member14is transmitted to the piston rod32via the connecting link38. The piston26is moved relative to the base12from the initial position P21to the actuated position P22in response to the pivotal movement of the operating member14relative to the base12from the rest position P11to the operated position P12.

As seen inFIG. 5, for example, when the operating member14is pivoted relative to the base12at a first pivot angle AG1from the rest position P11, the piston26moves from the initial position P21to a first actuated position P31by a first amount of movement AM1. In this embodiment, the first pivot angle AG1is 10 degrees.

As seen inFIG. 6, when the operating member14is pivoted relative to the base12at a second pivot angle AG2from the rest position P11, the piston26moves from the initial position P21to a second actuated position P32by a second amount of movement AM2. In this embodiment, the second pivot angle AG2is larger than the first pivot angle AG1and is 20 degrees. The second amount of movement AM2is longer than the first amount of movement AM1.

As seen inFIG. 7, when the operating member14is pivoted relative to the base12at a third pivot angle AG3from the rest position P11, the piston26moves from the initial position P21to the actuated position P22by a third amount of movement AM3. In this embodiment, the third pivot angle AG3is larger than the second pivot angle AG2and is 30 degrees. The third amount of movement AM3is longer than the second amount of movement AM2.

As seen inFIG. 8, an amount of movement of the piston26rapidly increases from the initial position P21to the first actuated position P31. An increase rate of the amount of movement of the piston26gradually decreases from the first actuated position P31to the actuated position P22through the second actuated position P32.

As seen inFIG. 4, the intermediate position P23is provided between the initial position P21and the first actuated position P31. Thus, it is possible to shorten a time lag from a timing at which the operating member14starts to pivot to a timing at which the piston26covers the connecting holes72. This improves response performance of the bicycle operating device10.

The bicycle operating device10includes the following features.

(1) With the bicycle operating device10, the connecting link38is pivotally coupled to each of the operating member14and the piston26to move the piston26relative to the hydraulic cylinder24in response to a pivotal movement of the operating member14relative to the base12. The guiding structure40is coupled to the piston26to guide the piston26relative to the base12. Accordingly, it is possible to change an amount of movement of the piston26relative to an amount of movement of the operating member14by changing a shape, a position, and/or a size of the connecting link38. Thus, it is possible to obtain a preferable movement ratio characteristic between the operating member14and the piston26.

(2) The operating member14is pivotally coupled to the base12about the first pivot axis PA1. The connecting link38is pivotally coupled to the operating member14about the second pivot axis PA2spaced apart from the first pivot axis PA1. The connecting link38is pivotally coupled to the piston26about a third pivot axis PA3spaced apart from the first and second pivot axes PA1and PA2. Accordingly, it is possible to smoothly transmit the pivotal movement of the operating member14to the piston26.

(3) The first, second and third pivot axes PA1, PA2and PA3are parallel to each other. Accordingly, it is possible to more smoothly transmit the pivotal movement of the operating member14to the piston26.

(4) The piston26is movable relative to the hydraulic cylinder24in a movement direction D1between an initial position P21and an actuated position P22. The second pivot axis PA2is disposed between the first and third pivot axes PA1and PA3in a perpendicular direction D2which is perpendicular to the movement direction D1. Accordingly, it is possible to shorten a size of the connecting link38, allowing the bicycle operating device10to be more compact.

(5) The hydraulic cylinder24includes a cylinder bore28in which the piston26is at least partially provided. The piston26and the cylinder bore28define a hydraulic chamber C1between the piston26and the cylinder bore28. The second pivot axis PA2is farther from the hydraulic chamber C1than the third pivot axis PA3in the movement direction D1in the initial state where the piston26is positioned at the initial position P21. Accordingly, it is possible to transmit a pushing force from the operating member14to the piston26via the connecting link38.

(6) In the initial state where the piston26is positioned at the initial position P21, the second pivot axis PA2is disposed at a position which is equal to a position of the first pivot axis PA1in the movement direction D1or which is closer to the third pivot axis PA3than the first pivot axis PA1in the movement direction D1. Accordingly, it is possible to quickly change the hydraulic pressure around a starting point of the second pivot axis PA2corresponding to the initial position P21of the piston26.

(7) The guiding structure40includes the guiding link42. The guiding link42is pivotally coupled to the piston26about the fourth pivot axis PA4. The guiding link42is pivotally coupled to the base12about the fifth pivot axis PA5. Accordingly, it is possible to make a movement of the piston26relative to the base12more stable because of the guiding link42.

(8) The fourth pivot axis PA4coincides with the third pivot axis PA3.

Accordingly, it is possible to simplify a connecting part provided among the piston26, the connecting link38, and the guiding link42.

(9) The connecting link38includes the first proximal end52and the first distal end54. The first proximal end52is pivotally coupled to the operating member14about the second pivot axis PA2. The first distal end54is pivotally coupled to the piston26about the third pivot axis PA3. Accordingly, it is possible to simplify the structure of the connecting link38.

(10) The hydraulic cylinder24includes the cylinder bore28. The piston26includes the piston body30and the piston rod32. The piston body30is movably provided in the cylinder bore28. The piston rod32is pivotally coupled to the piston body30to operatively couple the connecting link38to the piston body30. Accordingly, it is possible to simplify the structure of the piston body30.

(11) The operating member14is pivotally coupled to the base12about the first pivot axis PA1. The connecting link38is pivotally coupled to the operating member14about the second pivot axis PA2spaced apart from the first pivot axis PA1. The connecting link38is pivotally coupled to the piston rod32about the third pivot axis PA3spaced apart from the first and second pivot axes PA1and PA2. Accordingly, it is possible to smoothly transmit the pivotal movement of the operating member14to the piston26with simplifying the structure of the connecting link38.

(12) The guiding link42is pivotally coupled to the piston rod32about the fourth pivot axis PA4. The guiding link42is pivotally coupled to the base12about the fifth pivot axis PA5. Accordingly, it is possible to make a movement of the piston26relative to the base12more stable because of the guiding link42.

(13) The fourth pivot axis PA4coincides with the third pivot axis PA3. Accordingly, it is possible to simplify a connecting part provided among the piston rod32, the connecting link38, and the guiding link42.

(14) The bicycle operating device10further comprises the hydraulic reservoir60. The hydraulic reservoir60is connected to the hydraulic chamber C1defined by the piston26and the hydraulic cylinder24in the cylinder bore28. The hydraulic reservoir60can absorb change in volume of hydraulic fluid caused by change in a temperature of the hydraulic fluid.

Second Embodiment

A bicycle operating device210in accordance with a second embodiment will be described below referring toFIG. 9. The bicycle operating device210has the same structure as that of the bicycle operating device10except for a connecting link238and a guiding structure240. 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. 9, in the bicycle operating device210, the connecting link238and the guiding structure240are differently arranged in comparison with the connecting link38and the guiding structure40of the bicycle operating device10. The second pivot axis PA2is disposed between the third pivot axis PA3and the hydraulic chamber C1in the movement direction D1, at least in the initial state where the piston26is positioned at the initial position P21. In other words, the second pivot axis PA2is closer to the hydraulic chamber C1than the third pivot axis PA3in the movement direction D1, at least in the initial state. The second pivot axis PA2is disposed at a position which is equal to a position of the first pivot axis PA1in the movement direction D1or which is located between the third pivot axis PA3and the first pivot axis PA1in the movement direction D1in the initial state. In this embodiment, the second pivot axis PA2is disposed at a position closer to the third pivot axis PA3than the first pivot axis PA1in the movement direction D1in the initial state where the piston26is positioned at the initial position P21.

With the bicycle operating device210, it is possible to obtain substantially the same effects of those of the bicycle operating device10of the first embodiment.

Furthermore, the bicycle operating device210includes the following features.

(1) With the bicycle operating device210, the second pivot axis PA2is closer to the hydraulic chamber C1than the third pivot axis PA3in the movement direction D1in the initial state where the piston26is positioned at the initial position P21. Accordingly, it is possible to transmit a pulling force from the operating member14to the piston26via the connecting link238.

(2) The second pivot axis PA2is disposed at a position equal to a position of the first pivot axis PA1or closer to the third pivot axis PA3than the first pivot axis PA1in the movement direction D1in the initial state where the piston26is positioned at the initial position P21. Accordingly, it is possible to quickly change the hydraulic pressure around a starting point of the second pivot axis PA2corresponding to the initial position P21of the piston26.

Third Embodiment

A bicycle operating device310in accordance with a third embodiment will be described below referring toFIG. 10. The bicycle operating device310has the same structure as that of the bicycle operating device10except for the guiding structure340. 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. 10, the bicycle operating device310comprises a guiding structure340coupled to the piston26to guide the piston26relative to the base12. Unlike the guiding structure40of the first embodiment, the guiding link42is omitted from the guiding structure340in this embodiment. Instead, the guiding structure340includes a guiding bore341through which the piston26extends. The piston26and the cylinder bore28define a hydraulic chamber C1between the piston26and the cylinder bore28. The guiding bore341is provided on the base12between the hydraulic chamber C1and the third pivot axis PA3.

The guiding bore341is provided at the hydraulic cylinder24instead of the through-hole37. Unlike the through-hole37of the first embodiment, however, an inner peripheral surface of the guiding bore341is in slidable contact with the piston rod32. The guiding bore341has an inner diameter which is substantially equal to the outer diameter of the piston rod32of the piston26. The inner peripheral surface of the guiding bore341guides the piston rod32to move in the movement direction D1.

With the bicycle operating device310, it is possible to obtain substantially the same effects of those of the bicycle operating device10of the first embodiment.

Furthermore, the guiding bore341is provided on the base12between the hydraulic chamber C1and a third pivot axis PA3. Accordingly, it is possible to make a movement of the piston26relative to the base12more stable because of the guiding bore341.

It will be apparent to those skilled in the bicycle field from the present disclosure that the above embodiments can be at least partially combined with each other. For example, the arrangement of the connecting link238of the second embodiment can be applied to the bicycle operating device310of the third embodiment.