CN108466671B

CN108466671B - Bicycle transmission and bicycle assist system provided with same

Info

Publication number: CN108466671B
Application number: CN201810145335.0A
Authority: CN
Inventors: 山本贵士
Original assignee: Shimano Inc
Current assignee: Shimano Inc
Priority date: 2017-02-23
Filing date: 2018-02-12
Publication date: 2022-05-10
Anticipated expiration: 2038-02-12
Also published as: CN114194327B; CN114194327A; CN108466671A; JP2018136002A; DE102018202682A1; JP6756640B2; TWI742237B; TW201831370A

Abstract

The invention provides a bicycle transmission which is beneficial to usability and an auxiliary system for a bicycle with the same. A bicycle transmission includes a transmission mechanism including five or more gear shift stages having a gear ratio that increases stepwise, and among the five gear shift stages, when a ratio of a gear ratio of a minimum gear shift stage to a gear ratio of an intermediate gear shift stage is subtracted from a ratio of the gear ratio of the intermediate gear shift stage to the gear ratio of a maximum gear shift stage, a difference between any of the three gear shift stages is either positive or negative.

Description

Bicycle transmission and bicycle assist system provided with same

Technical Field

The present invention relates to a bicycle transmission and a bicycle assist system including the same.

Background

The bicycle transmission disclosed in patent document 1 includes a speed change mechanism that changes a gear ratio of a bicycle in stages. The speed change mechanism includes a gear position corresponding to a gear ratio of eight steps, and is configured such that, for each gear position, a ratio of the gear position one step lower than the gear position to the gear ratio of the gear position falls within a predetermined range. Therefore, when the gear position is changed, the gear ratio changes within a range of a predetermined ratio in any gear position.

Documents of the prior art

Patent document

Patent document 1: japanese patent No. 4564978

Depending on the type of bicycle or the user's request, the shift stage may be changed at a different frequency for each range of the gear ratio. Patent document 1 does not discuss this point at all. Therefore, there is still room for improvement in usability.

Disclosure of Invention

The invention aims to provide a bicycle transmission which is beneficial to usability and an auxiliary system for a bicycle with the bicycle transmission.

As one form of the bicycle transmission according to the first aspect of the present invention, it is provided with a speed change mechanism including five or more gear positions configured such that a gear ratio increases stepwise, and among successive three gear positions among the five or more gear positions, when a ratio of a gear ratio of a maximum gear position to a gear ratio of the intermediate gear position is subtracted from a ratio of a gear ratio of an intermediate gear position to a gear ratio of a minimum gear position, a difference between any of the successive three gear positions is one of positive and negative.

According to the above configuration, in the three consecutive gear positions, when the ratio of the gear ratio of the maximum gear position to the gear ratio of the intermediate gear position is subtracted from the ratio of the gear ratio of the intermediate gear position to the gear ratio of the minimum gear position, the difference is not "0". Therefore, the difference in the ratio of the gear ratios (the shift step length) in the successive gear positions is changed in a desired proportion in accordance with the user's request or the like, which is advantageous in terms of usability. In addition, the speed change step is one of positive and negative in any three consecutive gear shift stages, and therefore, may be oriented in a direction to increase or decrease the ratio of the speed change ratio depending on the gear shift stage.

In the bicycle transmission according to the second aspect of the first aspect, the five or more shift stages include a smallest shift stage in the shift mechanism.

According to the above configuration, the required speed change step can be realized from the viewpoint of the minimum speed change step, which is advantageous in terms of usability.

In the bicycle transmission according to the third aspect of the first or second aspect, the absolute value of the difference is 0.03 or more and 0.15 or less.

According to the above configuration, since the absolute value of the shift step length is 0.03 to 0.15 inclusive, that is, the shift step length is 3 to 15% inclusive, it is possible to suppress an excessive change in the pedal operation feeling when changing the gear position.

As one form of the bicycle transmission according to the fourth aspect of the present invention, it is provided with a transmission mechanism including four or more gear shift stages configured such that the gear ratio increases stepwise, and in successive three gear shift stages among the four or more gear shift stages, when the ratio of the gear ratio of the maximum gear shift stage to the gear ratio of the intermediate gear shift stage is subtracted from the ratio of the gear ratio of the intermediate gear shift stage to the gear ratio of the minimum gear shift stage, the difference is both positive and negative in any of the successive three gear shift stages, and the absolute value of the difference is both 0.03 or more and 0.15 or less.

According to the above configuration, in the three consecutive gear positions, when the ratio of the gear ratio of the maximum gear position to the gear ratio of the intermediate gear position is subtracted from the ratio of the gear ratio of the intermediate gear position to the gear ratio of the minimum gear position, the difference is not "0". Therefore, the difference in the ratio of the gear ratios (the shift step length) in the successive gear positions is changed in a desired proportion in accordance with the user's request or the like, which is advantageous in terms of usability. In addition, in any of the three consecutive gear shift stages, the gear shift step length is one of positive and negative, and therefore, it is possible to orient in a direction to increase or decrease the ratio of the gear shift ratio depending on the gear shift stage. Further, since the absolute value of the shift step length is 0.03 to 0.15, that is, the shift step length changes within 3 to 15%, it is possible to suppress an excessive change in the pedal operation feeling when changing the gear position.

In the bicycle transmission according to the fifth aspect of the fourth aspect, the four or more shift stages include a smallest shift stage in the shift mechanism.

In a bicycle transmission according to a sixth aspect of the fourth or fifth aspect, the speed change mechanism includes five or more gear shift stages configured such that a gear ratio increases stepwise, and the three consecutive gear shift stages are included in the five or more gear shift stages.

According to the above configuration, even in the transmission mechanism including five or more gear positions, it is advantageous in terms of usability.

In the bicycle transmission according to the seventh aspect of any one of the third to sixth aspects, an absolute value of the difference is 0.04 or more and 0.1 or less.

According to the above configuration, since the absolute value of the shift step length is 0.04 to 0.1, that is, the shift step length is 4% to 10%, it is possible to further suppress an excessive change in the pedal operation feeling when changing the shift stage.

In the bicycle transmission according to the eighth aspect of any one of the first to seventh aspects, the difference is positive for any of the three consecutive shift speeds.

According to the above configuration, since the shift step length is always positive, the ratio of the speed ratio of the shift stage one step higher than a certain shift stage to the speed ratio of the shift stage is larger as the shift stage is smaller. Therefore, when the bicycle is driven with the pedal frequency kept within a certain range, the frequency of changing the gear position of the bicycle in a low speed region can be reduced.

In the bicycle transmission according to the ninth aspect of any one of the first to eighth aspects, an absolute value of a value obtained by subtracting one of the differences from the other of the differences is 0.005 or more and 0.02 or less.

According to the above configuration, the absolute value of the value obtained by subtracting one of the two shift steps of three consecutive shift stages from the other is 0.005 or more and 0.02 or less. Therefore, when the ratio of the gear ratio of a gear stage one step higher than the predetermined gear stage to the gear ratio of the predetermined gear stage is plotted on a graph, it can be approximated by a flat line. Therefore, when traveling with the pedal frequency kept within a certain range, the time for switching the shift stage corresponding to the increase in the speed of the bicycle is fixed.

In the bicycle transmission according to the tenth aspect of any one of the first to ninth aspects, the shifting mechanism is an internal shifting mechanism.

According to the above configuration, the internal transmission mechanism is also advantageous in terms of usability.

The bicycle transmission according to an eleventh aspect of the tenth aspect further includes a hub for housing the internal transmission mechanism.

According to the above configuration, the internal speed change mechanism provided in the hub, that is, the internal speed change hub, is advantageous in terms of usability.

In accordance with a twelfth aspect of the present invention, there is provided an assist system for a bicycle, comprising: the bicycle transmission according to any one of the first to eleventh aspects; and a motor for assisting the manual driving force.

According to the above configuration, since the motor assists the manual driving force, the burden on the rider can be reduced even in a state where the gear ratio is low with respect to the vehicle speed. In addition, according to the bicycle assist system, since the manual driving force is assisted by the motor, the frequency of changing the gear position of the bicycle in a low speed region is reduced. Therefore, by using the bicycle transmission according to any one of the first to eleventh aspects, the time for changing the gear position can be optimized.

The bicycle transmission according to a thirteenth aspect of the twelfth aspect further includes an operating portion that is manually operated to operate the bicycle transmission, and the bicycle transmission changes a gear ratio of a bicycle according to an operation of the operating portion.

According to the above configuration, since the time for changing the gear position can be optimized, the burden on the rider when operating the operation unit can be reduced.

ADVANTAGEOUS EFFECTS OF INVENTION

The transmission for the bicycle and the auxiliary system for the bicycle with the transmission are beneficial to usability.

Drawings

Fig. 1 is a side view of a bicycle equipped with an assist system for a bicycle according to an embodiment;

FIG. 2 is a front elevational view of the bicycle transmission of the bicycle assist system of FIG. 1;

FIG. 3 is a partial cross-sectional view of the bicycle derailleur of FIG. 2;

FIG. 4 is a perspective view of the bushing of the transmission for the bicycle of FIG. 3;

FIG. 5 is a schematic view showing the relationship of the bushing of FIG. 3 and a first setting member;

FIG. 6 is a schematic diagram of the bicycle transmission of FIG. 3;

FIG. 7 is a schematic diagram illustrating shift paths for a first gear ratio step of the bicycle transmission of FIG. 3;

FIG. 8 is a schematic diagram illustrating shift paths for a second gear ratio step of the bicycle transmission of FIG. 3;

FIG. 9 is a schematic diagram illustrating shift paths for a third gear ratio step of the bicycle transmission of FIG. 3;

FIG. 10 is a schematic diagram illustrating shift paths for a fourth gear ratio step of the bicycle transmission of FIG. 3;

FIG. 11 is a schematic diagram illustrating shift paths for a fifth gear ratio step of the bicycle transmission of FIG. 3;

fig. 12 is a graph showing a relationship between a shift speed, a pedal frequency, and a vehicle speed of the bicycle transmission of fig. 3.

Detailed Description

A bicycle 10 with an embodiment of a bicycle assist system 40 mounted thereon will be explained with reference to fig. 1 to 12.

As shown in fig. 1, the bicycle 10 includes a body 12, a drive mechanism 14, a front wheel 16, a rear wheel 18, and a bicycle assist system 40. The vehicle body 12 includes a frame 12A and a handle 12B attached to the frame 12A.

The drive mechanism 14 includes a crank 20, a pedal 22, a front rotary body 24, a transmission member 26, and a rear rotary body 28. The crank 20 includes a crank shaft 20A and a crank arm 20B. The drive mechanism 14 transmits the manual drive force applied to the pedals 22 to the rear wheel 18. The front rotary body 24 comprises a sprocket, pulley or bevel gear. The rear rotating body 28 includes a sprocket, pulley or bevel gear. The transmission member 26 is configured to transmit the rotation of the crank 20 to the rear wheel 18 via, for example, a chain, a belt, or a shaft. The front rotor 24 is coupled to the crankshaft 20A via a one-way clutch (not shown). The one-way clutch rotates the front rotary body 24 forward in the case where the crank 20 rotates forward, and does not rotate the front rotary body 24 backward in the case where the crank 20 rotates backward. The front rotary body 24 may be coupled to the crankshaft 20A without a one-way clutch.

The bicycle assist system 40 includes a bicycle transmission 50 and a motor 42. The bicycle assist system 40 further includes an operating unit 44 and a battery unit 46. The bicycle assist system 40 is mounted on the bicycle 10.

The motor 42 assists the manual driving force. The motor 42 is supported by the frame 12A. In one example, the motor 42 is provided around the crank shaft 20A, and transmits the torque of the motor 42 to the crank shaft 20A. In another example, the motor 42 is disposed around the axle 16A of the front wheel 16 or the axle 18A of the rear wheel 18, and transmits the torque of the motor 42 to the front wheel 16 or the rear wheel 18.

The operating portion 44 is operated by a human hand to operate the bicycle transmission 50. In one example, the operating portion 44 is provided on the handlebar 12B. One end of a bowden cable (not shown) is attached to the operation unit 44. By the user operating the operating portion 44, the inner cable C1 (see fig. 2) of the bowden cable moves. The other end of the bowden cable is attached to the bicycle derailleur 50.

The battery unit 46 provides power to the motor 42. The battery unit 46 includes a battery cell 46A and a battery holder 46B for mounting the battery unit 46 to the vehicle body frame 12A.

The bicycle derailleur 50 changes the gear ratio of the bicycle 10 in response to an operation of the operating unit 44. The bicycle transmission 50 includes a shift mechanism 62. The shift mechanism 62 is an internal shift mechanism. The bicycle transmission 50 includes a hub 18C. The hub 18C houses the internal transmission mechanism. That is, as shown in fig. 2, the bicycle transmission 50 is integrally provided to an inner hub of the hub 18C.

As shown in fig. 3, a bicycle transmission 50 serving as an internal transmission hub includes a transmission mechanism 52 and a setting mechanism 54. The bicycle transmission 50 further includes a support member 56, an input member 58, and an output member 60. The support member 56 is formed integrally with the axle 18A of the rear wheel 18. The input body 58 is provided around the support member 56 so as to be rotatable integrally with the rear rotating body 28. The output body 60 is a hub shell. The output body 60 includes a flange 60A for mounting the spokes 18B of the rear wheel 18. The bicycle transmission 50 changes the speed of rotation of the input member 58 and transmits the changed speed to the output member 60.

As shown in fig. 3, the transmission mechanism 52 includes a plurality of shifting mechanisms 62. The plurality of shift mechanisms 62 includes at least a first shift mechanism 62A. The plurality of shift mechanisms 62 further includes a second shift mechanism 62B. The transmission mechanism 52 transmits the rotation from the input member 58 to the output member 60 at three or more gear ratios. The speed change mechanism 62 can change the speed of rotation from the input member 58 and transmit the rotation to the output member 60. The speed change mechanism 62 includes four or more gear positions whose gear ratio increases stepwise. The speed change mechanism 62 includes five or more speed change stages with a speed change ratio gradually increased. The shift mechanism 62 shown in fig. 3 includes five shift stages.

The plurality of shifting mechanisms 62 includes at least one

planetary mechanism

64, 66, 68, 70, respectively. The plurality of shift mechanisms 62 includes a first planetary mechanism 64 and a second planetary mechanism 66. The plurality of shift mechanisms 62 further includes a third planetary mechanism 68 and a fourth planetary mechanism 70. Specifically, the first shift mechanism 62A includes a first planetary mechanism 64 and a second planetary mechanism 66. The second shift mechanism 62B includes a third planetary mechanism 68 and a fourth planetary mechanism 70. The first planetary mechanism 64 is disposed adjacent to the input body 58 in the axial direction of the bicycle transmission 50. The second planetary mechanism 66 is disposed beside the first planetary mechanism 64 in the axial direction of the bicycle transmission 50 and on the opposite side of the input body 58. The fourth planetary mechanism 70 is disposed beside the second planetary mechanism 66 in the axial direction of the bicycle transmission 50 and on the opposite side of the first planetary mechanism 64. The third planetary mechanism 68 is disposed adjacent to the fourth planetary mechanism 70 in the axial direction of the bicycle transmission 50 and on the opposite side of the second planetary mechanism 66.

The first planetary mechanism 64 includes a first sun gear 72, a first ring gear 74, first planet gears 76, and a first carrier 78. The first sun gear 72 is supported around the shaft of the support member 56 and is rotatable relative to the support member 56. The first ring gear 74 is disposed around the first sun gear 72. The first planetary gears 76 are engaged with the first sun gear 72, and can revolve with respect to the first sun gear 72 and the first ring gear 74. The first planetary mechanism 64 includes a plurality of first planetary gears 76. The first carrier 78 rotatably supports the plurality of first planetary gears 76, respectively. The first carrier 78 is provided to be rotatable about the axis of the support member 56. The plurality of first planetary gears 76 revolve around the first sun gear 72 with the rotation of the first carrier 78, respectively. First carrier 78 is connected to input member 58 and transmits rotation from input member 58. The first planetary mechanism 64 is configured to increase the speed of rotation from the input body 58 and output the rotation.

The second planetary mechanism 66 includes a second sun gear 80, a second ring gear 82, second planet gears 84, and a second carrier 86. The second sun gear 80 is supported around the shaft of the support member 56 and is rotatable relative to the support member 56. The second ring gear 82 is disposed around the second sun gear 80. The second planetary gears 84 engage with the second sun gear 80 and are capable of revolving relative to the second sun gear 80 and the second ring gear 82. The second planetary mechanism 66 includes a plurality of second planetary gears 84. The second carrier 86 rotatably supports the plurality of second planetary gears 84, respectively. The second carrier 86 is provided to be rotatable about the axis of the support member 56. The plurality of second planetary gears 84 revolve around the second sun gear 80 in accordance with the rotation of the second carrier 86, respectively. The second planetary mechanism 66 is configured to increase the speed of rotation from the input body 58 and output the rotation. The second carrier 86 is connected to the input body 58 so as to transmit rotation from the input body 58.

Each of the first planetary mechanism 64 and the second planetary mechanism 66 is configured to increase the speed of rotation from the input member 58 and output the rotation. The first sun gear 72 has a smaller number of teeth than the second sun gear 80. The first planetary gears 76 have a larger number of teeth than the second planetary gears 84. The number of teeth of the first ring gear 74 and the number of teeth of the second ring gear 82 are equal. The first ring gear 74 and the second ring gear 82 are formed on a first ring gear member 88. The first ring gear member 88 includes a first gear portion 88A. The first gear portion 88A is shared by the first ring gear 74 and the second ring gear 82. The first and second planet gears 76, 84 are formed on the first planet gear member 90. The first planetary gear member 90 constitutes a so-called planetary gear with steps. The first carrier 78 and the second carrier 86 are integrally formed.

The third planetary mechanism 68 includes a third sun gear 92, a third ring gear 94, third planetary gears 96, and a third carrier 98. The third sun gear 92 is supported around the shaft of the support member 56 and is rotatable relative to the support member 56. The third ring gear 94 is disposed around the third sun gear 92. The third planetary gears 96 are engaged with the third sun gear 92 and can revolve with respect to the third sun gear 92 and the third ring gear 94. The third planetary mechanism 68 includes a plurality of third planetary gears 96. The third carrier 98 rotatably supports the plurality of third planetary gears 96, respectively. The third carrier 98 is provided rotatably about the axis of the support member 56. The plurality of third planetary gears 96 revolve around the third sun gear 92 in accordance with the rotation of the third carrier 98, respectively. The third carrier 98 is connected with the first ring gear member 88, thereby transmitting rotation from the first ring gear member 88.

The fourth planetary mechanism 70 includes a fourth sun gear 100, a fourth ring gear 102, fourth planet gears 104, and a fourth carrier 106. The fourth sun gear 100 is supported around the shaft of the support member 56 and is rotatable relative to the support member 56. The fourth ring gear 102 is disposed around the fourth sun gear 100. The fourth planetary gear 104 is engaged with the fourth sun gear 100, and can revolve with respect to the fourth sun gear 100 and the fourth ring gear 102. The fourth planetary mechanism 70 includes a plurality of fourth planetary gears 104. The fourth carrier 106 rotatably supports the plurality of fourth planetary gears 104, respectively. Fourth gear carrier 106 is provided to be rotatable about the axis of support member 56. The plurality of fourth planetary gears 104 revolve around the fourth sun gear 100 in accordance with the rotation of the fourth carrier 106, respectively. The fourth carrier 106 is connected with the first ring gear member 88, thereby transmitting rotation from the first ring gear member 88.

The third planetary mechanism 68 is configured to increase the speed of rotation from the input body 58 and output the rotation. The fourth planetary mechanism 70 is configured to increase the speed of rotation from the input body 58 and output the rotation. The third sun gear 92 has a smaller number of teeth than the fourth sun gear 100. The third planetary gears 96 have a larger number of teeth than the fourth planetary gears 104. The number of teeth of the third ring gear 94 and the number of teeth of the fourth ring gear 102 are equal. The third ring gear 94 and the fourth ring gear 102 are formed on the second ring gear member 108. The second ring gear member 108 includes a second gear portion 108A. The second gear portion 108A is shared by the third ring gear 94 and the fourth ring gear 102. Third planet gears 96 and fourth planet gears 104 are formed on second planet gear member 110. The second planetary gear member 110 constitutes a so-called stepped planetary gear. Third carrier 98 and fourth carrier 106 are integrally formed.

The setting mechanism 54 sets the shift path S in the transmission mechanism 52 for the rotation of the input body 58. The setting mechanism 54 sets one of the plurality of shift paths S. The plurality of shift paths S includes a first shift path S10 (fig. 8). The plurality of shift paths S further include a second shift path S20 (fig. 9). The transmission mechanism 52 also forms a non-shift path S0 (fig. 7) through which the rotation of the input member 58 is output to the output member 60 without being shifted in speed by the non-shift path S0 (fig. 7).

As shown in fig. 3, the setting mechanism 54 includes a first setting member 112, a second setting member 114, a third setting member 116, a fourth setting member 118, a control member 120, a boss 122, a first switching portion 124, and a second switching portion 126.

The first setting member 112 sets the first sun gear 72 in any one of a rotational state in which it is rotatable relative to the support member 56 and a restricted state in which it is not rotatable relative to the support member 56. The second setting member 114 sets the second sun gear 80 to any one of a rotational state in which it is rotatable relative to the support member 56 and a restricted state in which it is not rotatable relative to the support member 56. The third setting member 116 sets the third sun gear 92 in any one of a rotational state in which it is rotatable relative to the support member 56 and a restricted state in which it is not rotatable relative to the support member 56. The fourth setting member 118 sets the fourth sun gear 100 to any one of a rotation state in which it is rotatable relative to the support member 56 and a restricted state in which it is not rotatable relative to the support member 56.

The control member 120 is disposed around the support member 56 and is rotatable relative to the support member 56. The control member 120 is connected to a rotating body C2 (see fig. 2) to which an end of the inner cable C1 is connected, and rotates integrally with the rotating body C2. When the inner cable C1 is moved by operating the operation unit 44 (see fig. 1), the rotating body C2 rotates. Therefore, the control member 120 also rotates around the support member 56 with the rotation of the rotating body C2.

As shown in fig. 4, the boss 122 includes a first arm portion 122A, a second arm portion 122B, a third arm portion 122C, a fourth arm portion 122D, and a base portion 122E. The arm portions 122A to 122D are curved in the circumferential direction of the support member 56. The base portion 122E extends in the axial direction of the support member 56, and connects the arm portions 122A to 122D. The number of arm portions 122A to 122D is equal to the number of setting

members

112, 114, 116, 118. The arm portions 122A to 122D are each formed with an inclined surface at an end portion or an intermediate portion in the extending direction of the arm portions 122A to 122D. The boss 122 is fitted into the control member 120, and rotates around the support member 56 integrally with the control member 120.

As shown in fig. 5, the first setting member 112 is disposed between the first sun gear 72 and the support member 56. The first setting member 112 includes a claw portion 112A and an engaging portion 112B that engages with the inner peripheral surface of the first arm portion 122A. When the first arm portion 122A rotates around the support member 56, the engaging portion 112B moves along the inclined surface of the first arm portion 122A, and the first setting member 112 rotates. The state in which the claw portion 112A protrudes toward the recess portion of the inner peripheral portion of the first sun gear 72 (solid line in fig. 5) is a restricted state in which the first sun gear 72 is not rotatable with respect to the support member 56. The claw portion 112A is pulled out from the recess portion of the inner peripheral portion of the first sun gear 72 (the two-dot chain line in fig. 5) to be in a rotatable state in which the first sun gear 72 is rotatable with respect to the support member 56. In fig. 5, the relationship among the first setting member 112, the first sun gear 72, and the first arm portion 122A is described, but the rotational state and the restricted state of the sun gears 80, 92, and 100 may be formed by other members with the same configuration. The second sun gear 80 is set in the rotation state and the restricted state by the second setting member 114 and the second arm portion 122B. The third sun gear 92 is set in the rotation state and the restricted state by the third setting member 116 and the third arm portion 122C. The fourth sun gear 100 is set in the rotation state and the restricted state by the fourth setting member 118 and the fourth arm portion 122D.

When one of the first sun gear 72 and the second sun gear 80 is in the restricted state, the setting mechanism 54 shown in fig. 4 controls the first setting member 112 and the second setting member 114 so that the other of the first sun gear 72 and the second sun gear 80 is in the rotation state. When one of the third sun gear 92 and the fourth sun gear 100 is in the restricted state, the setting mechanism 54 controls the third setting member 116 and the fourth setting member 118 so that the other of the third sun gear 92 and the fourth sun gear 100 is in the rotation state. The setting mechanism 54 sets the inclined surfaces of the arm portions 122A to 122D of the sleeve 122 at different positions in the circumferential direction, thereby making the rotational phases of the control member 120, which switches the rotational states and the restricted states of the sun gears 72, 80, 92, 100, different.

The first switching portion 124 and the second switching portion 126 form a first state in which the rotation of the input body 58 is output to the output body 60 by the shift of the second shift mechanism 62B, and a second state; in the second state, the rotation of the input member 58 is output to the output member 60 without being shifted by the second shift mechanism 62B.

The first switching portion 124 includes a first one-way clutch 124A. The first one-way clutch 124A is, for example, a roller clutch. The first one-way clutch 124A is disposed between the second ring gear member 108 and the output body 60. Specifically, the second ring gear member 108 is formed integrally with the inner race of the first one-way clutch 124A, and the inner peripheral portion of the output body 60 is formed integrally with the outer race of the first one-way clutch 124A. The first one-way clutch 124A allows the second ring gear member 108 to rotate relative to the output body 60 when the rotational speed of the second ring gear member 108 is lower than the rotational speed of the output body 60. When the rotational speed of the second ring gear member 108 is equal to or greater than the rotational speed of the output body 60, the first one-way clutch 124A rotates the first ring gear member 88 integrally with the output body 60.

The second switching portion 126 includes a second one-way clutch 126A. The second one-way clutch 126A is, for example, a one-way clutch having pawls. Second one-way clutch 126A is disposed between third carrier 98 and fourth carrier 106 and output member 60. Second one-way clutch 126A transmits the rotation of third carrier 98 and fourth carrier 106 to output body 60, but does not transmit the rotation of output body 60 to third carrier 98 and fourth carrier 106.

When both the first sun gear 72 and the second sun gear 80 are in a rotating state and both the third sun gear 92 and the fourth sun gear 100 are in a rotating state, the rotation input to the first planetary mechanism 64, the second planetary mechanism 66, the third planetary mechanism 68, and the fourth planetary mechanism 70 is not increased in speed. Therefore, the rotation of the input member 58 is output to the output member 60 through the first switching unit 124 without being subjected to the speed change of the first planetary mechanism 64, the second planetary mechanism 66, the third planetary mechanism 68, and the fourth planetary mechanism 70. Second switching unit 126 allows relative rotation between third carrier 98 and fourth carrier 106 and output member 60.

When one of the first sun gear 72 and the second sun gear 80 is in the restricted state and both of the third sun gear 92 and the fourth sun gear 100 are in the rotating state, the rotation input to the third planetary mechanism 68 and the fourth planetary mechanism 70 is not increased. Therefore, the rotation of the input member 58 is output to the output member 60 through the first switching unit 124 without being shifted by the third planetary mechanism 68 and the fourth planetary mechanism 70. Second switching unit 126 allows relative rotation between third carrier 98 and fourth carrier 106 and output member 60.

When one of the first sun gear 72 and the second sun gear 80 is in the restricted state and one of the third sun gear 92 and the fourth sun gear 100 is in the restricted state, the rotation input to the third planetary mechanism 68 or the fourth planetary mechanism 70 is increased. Therefore, the rotation of the input member 58 is output to the output member 60 through the second switching portion 126 through the gear change of the third planetary mechanism 68 or the fourth planetary mechanism 70.

The transmission mechanism 52 forms at least a first shift path S10 and a second shift path S20. The first speed change path S10 transmits the rotation from the input member 58 to the output member 60 at least through the speed change of the first speed change mechanism 62A at one of the first speed change ratio and the second speed change ratio of the speed change ratios of three or more. The second shift path S20 is shifted by the second shift mechanism 62B different from the shift mechanism 62 that has passed through the first shift path S10, and transmits the rotation from the input member 58 to the output member 60 at a speed ratio larger than the first speed ratio and the second speed ratio.

The first shift path S10 includes a first planetary shift path S11 and a second planetary shift path S12. The first planetary shift path S11 transmits the rotation from the input body 58 to the output body 60 at the first gear ratio through the gear shift of the first planetary mechanism 64 without through the gear shift of the second planetary mechanism 66. The second planetary speed change path S12 transmits the rotation from the input member 58 to the output member 60 at the second speed change ratio through speed change of the second planetary mechanism 66 without speed change of the first planetary mechanism 64.

The setting mechanism 54 sets the transmission mechanism 52 so that the second shift path S20 does not undergo shifting of the first planetary mechanism 64. The second shift path S20 includes a third planetary shift path S21 and a fourth planetary shift path S22. The third planetary shift path S21 transmits the rotation from the input member 58 to the output member 60 at a third speed ratio larger than the second speed ratio through the speed change of the third planetary mechanism 68 and not through the speed change of the fourth planetary mechanism 70. The fourth planetary shift path S22 transmits the rotation from the input member 58 to the output member 60 at a fourth speed ratio larger than the third speed ratio through the speed change of the fourth planetary mechanism 70 without the speed change of the third planetary mechanism 68.

Next, the relationship between each gear position and the components of the transmission mechanism 52 will be described with reference to fig. 6 to 11 and table 1.

As shown in fig. 6 and table 1, in the first speed change stage, the first sun gear 72 is in a rotating state, the second sun gear 80 is in a rotating state, the third sun gear 92 is in a rotating state, and the fourth sun gear 100 is in a rotating state. As shown in fig. 7, in the first gear shift stage, the shift path S forms a non-shift path S0. In this case, the speed ratio is the minimum speed ratio R0. The minimum speed ratio R0 is "1".

As shown in fig. 6 and table 1, in the second speed change stage, the first sun gear 72 is in the restricted state, the second sun gear 80 is in the rotating state, the third sun gear 92 is in the rotating state, and the fourth sun gear 100 is in the rotating state. As shown in fig. 8, in the second gear shift stage, the speed change path S forms a first speed increasing path S1. The first speed increasing path S1 passes through the first shift path S10 without passing through the second shift path S20. The shift path S forms a first speed increasing path S1, and the first speed increasing path S1 passes only the first planetary shift path S11 in the first shift path S10. In this case, the gear ratio forms a first speed-increasing ratio R1 that is greater than the minimum gear ratio R0.

As shown in fig. 6 and table 1, in the third speed change stage, the first sun gear 72 is in the restricted state, the second sun gear 80 is in the rotating state, the third sun gear 92 is in the restricted state, and the fourth sun gear 100 is in the rotating state. As shown in fig. 9, in the third speed change stage, the speed change path S forms a second speed increasing path S2. The second speed increasing path S2 passes through the first shift path S10 and the second shift path S20. The shift path S forms a second speed increasing path S2 through which the second speed increasing path S2 passes through a first planetary shift path S11 in the first shift path S10 and a third planetary shift path S21 in the second shift path S20. In this case, the gear ratio forms a second speed-increasing ratio R2 that is larger than the first speed-increasing ratio R1.

As shown in fig. 6 and table 1, in the fourth speed change stage, the first sun gear 72 is in the restricted state, the second sun gear 80 is in the rotated state, the third sun gear 92 is in the rotated state, and the fourth sun gear 100 is in the restricted state. As shown in fig. 10, in the fourth gear shift stage, the speed change path S forms a third speed increasing path S3. The third speed increasing path S3 passes through the first shift path S10 and the second shift path S20. The shift path S forms a third speed increasing path S3, and the third speed increasing path S3 passes through the first planetary shift path S11 in the first shift path S10 and the fourth planetary shift path S22 in the second shift path S20. In this case, the gear ratio forms a third speed-increasing ratio R3 that is larger than the second speed-increasing ratio R2.

As shown in fig. 6 and table 1, in the fifth speed change stage, the first sun gear 72 is in a rotating state, the second sun gear 80 is in a restricted state, the third sun gear 92 is in a rotating state, and the fourth sun gear 100 is in a restricted state. As shown in fig. 11, in the fifth gear shift stage, the shift path S forms a fourth speed increase path S4. The fourth speed increasing path S4 passes through the first shift path S10 and the second shift path S20. The shift path S forms a fourth speed increasing path S4 through which the fourth speed increasing path S4 passes through the second planetary shift path S12 in the first shift path S10 and the fourth planetary shift path S22 in the second shift path S20. In this case, the gear ratio forms a fourth speed-increasing ratio R4 that is larger than the third speed-increasing ratio R3.

Table 1:

table 2 shows an example of the number of teeth of the gears of each of the

planetary mechanisms

64, 66, 68, and 70 according to the present embodiment.

Table 2:

	number of teeth of sun gear	Number of teeth of planetary gear	Number of teeth of gear ring
				First planetary mechanism	40	22	72
Second planetary mechanism	44	14	72
				Third planetary mechanism	36	24	72
Fourth planetary mechanism	44	14	72

Next, the gear ratio in each gear position will be described with reference to table 3. The "difference dA" indicates a difference (gear step) obtained by subtracting the ratio P of the gear ratio of the maximum gear position to the gear ratio of the intermediate gear position from the ratio P of the gear ratio of the intermediate gear position to the gear ratio of the minimum gear position in three consecutive gear positions out of five or more gear positions. The transmission 50 for a bicycle shown in table 3 has five gear positions.

In the shift mechanism 62, the difference (shift step length) dA is positive for any three consecutive shift speeds. The five shift stages include the smallest shift stage in the shift mechanism 62. The absolute value of the difference dA is 0.03 to 0.15. Preferably, the absolute value of the difference dA is 0.04 or more and 0.1 or less.

In any of the three consecutive gear steps, the difference dA is positive. Specifically, the difference dA is positive in any of the first to third speed change stages, the second to fourth speed change stages, and the third to fifth speed change stages. The absolute value of the value dX obtained by subtracting one of the differences dA from the other difference dA is 0.005 to 0.02.

Table 3:

next, the operation of the bicycle transmission 50 will be explained with reference to fig. 12.

A solid line L11 in fig. 12 shows a relationship between the kick frequency and the vehicle speed when the first gear shift stage of the bicycle transmission 50 is used. The solid line L12 shows the relationship between the kick frequency and the vehicle speed when the second gear shift stage of the bicycle transmission 50 is used. The solid line L13 shows the relationship between the pedaling frequency and the vehicle speed when the third gear shift stage of the bicycle transmission 50 is used. The solid line L14 shows the relationship between the kick frequency and the vehicle speed when the fourth gear shift stage of the bicycle transmission 50 is used. The solid line L15 shows the relationship between the kick frequency and the vehicle speed when the fifth gear shift stage of the bicycle transmission 50 is used.

The chain double-dashed line L21 in fig. 12 shows the relationship between the kick frequency and the vehicle speed when the first gear shift stage of the virtual bicycle transmission in which the difference dA is always "0" is used. The chain double-dashed line L22 shows the relationship between the pedaling frequency and the vehicle speed when the virtual bicycle transmission is used at the second gear position. The chain double-dashed line L23 shows the relationship between the pedaling frequency and the vehicle speed when the virtual third gear shift stage of the bicycle transmission is used. The chain double-dashed line L24 shows the relationship between the pedaling frequency and the vehicle speed when the virtual fourth gear shift stage of the bicycle transmission is used. The chain double-dashed line L25 shows the relationship between the pedaling frequency and the vehicle speed when the virtual fifth gear shift stage of the bicycle transmission is used.

For example, when the pedal frequency is increased to 70rpm, the speed of the bicycle 10 is increased by increasing the gear position by one step, and in such a traveling, the time required for the operation unit 44 to perform the operation of increasing the gear position is shortened as the gear position is reduced in the virtual bicycle transmission. Specifically, the amount of change in the vehicle speed required for the first gear to be changed to the second gear by stepping up to 70rpm is smaller than the amount of change in the vehicle speed required for the second gear to be changed to the third gear by stepping up to 70 rpm. Therefore, the smaller the gear shift stage is, the more frequently the operation of raising the gear shift stage is performed.

In the bicycle transmission 50, the time required for the operation unit 44 to raise the gear position is maintained within a predetermined range regardless of the size of the gear position. Therefore, the rider can perform the operation for changing the gear position within a stable time period according to the change in the vehicle speed.

(modification example)

The above embodiments are examples of the form that can be adopted by the bicycle transmission and the bicycle assist system provided with the bicycle transmission according to the present invention, and are not intended to limit the form thereof. The bicycle transmission and the bicycle assist system provided with the same according to the present invention can be combined with at least two modifications of the above embodiment, for example, as described below. In the following modifications, the same portions as those of the embodiment are denoted by the same reference numerals as those of the embodiment, and thus, description thereof is omitted.

The absolute value of the difference dA may also be set to be less than 0.03 or greater than 0.15 in five shift stages in which the speed ratio of the speed change mechanism 62 is increased stepwise.

In the three consecutive shift stages out of the four shift stages out of the five or more shift stages, the difference dA may be positive and negative in any of the three consecutive shift stages, and the absolute value of the difference dA may be 0.03 or more and 0.15 or less. In this case, the difference dA may be set to "0" in three consecutive gear positions including the gear positions other than the four gear positions. In the above embodiment, the gear shift stage other than the four gear shift stages is the first gear shift stage or the fifth gear shift stage.

In three consecutive gear shift stages among the five or more gear shift stages, the difference dA may be negative.

The bicycle transmission 50 may include six or more gear positions. In this case, the difference dA is one of positive and negative also in any three consecutive shift stages among the six shift stages. When the bicycle transmission 50 includes six or more gear positions, the difference dA between three consecutive gear positions of five consecutive gear positions may be one of positive and negative, or the difference dA between three gear positions including gear positions other than the five consecutive gear positions may be the other of positive and negative. The difference dA between three gear positions including the gear positions other than the five consecutive gear positions may be set to "0" instead of the other of the positive and negative gear positions.

The absolute value of the value dX obtained by subtracting one of the differences dA from the other of the differences dA may be set to be less than 0.005 or greater than 0.02.

The bicycle derailleur 50 may be mounted on the bicycle 10 without the motor 42. In this case, since the requirement of fixing the gear position with respect to the change of the vehicle speed of the bicycle can be fulfilled, the usability is improved.

The bicycle transmission 50 may be provided around the crank shaft 20A. In this case, the bicycle transmission 50 changes the speed of the rotation input to the crankshaft 20A and outputs the changed speed to the front rotor 24.

At least one of the first to fourth

planetary mechanisms

64, 66, 68, and 70 may be a planetary roller mechanism.

The first planetary gears 76, the second planetary gears 84, the third planetary gears 96, and the fourth planetary gears 104 of the first to fourth

planetary mechanisms

64, 66, 68, 70 may be provided in one member, and may be formed as stepped planetary gears of four stages.

At least one of the first to fourth

planetary mechanisms

64, 66, 68, and 70 may be a mechanism for decelerating and outputting the input rotation.

The bicycle 10 may be provided with a control unit for controlling the bicycle transmission 50. For example, the control unit controls the bicycle transmission 50 such that the pedal frequency is within a predetermined range, and changes the gear position. In this case, the timing for the control portion to control the bicycle transmission 50 is fixed with respect to the vehicle speed, and therefore, the rider does not easily feel discomfort.

Description of the symbols

10 … bicycle

18C … wheel hub

40 … bicycle assist system

42 … Motor

44 … operation part

50 … bicycle transmission

62 … speed change mechanism

Claims

1. A speed-changing device for a bicycle is provided,

the transmission mechanism includes five or more gear positions configured to increase a gear ratio stepwise, the transmission mechanism being configured to increase a speed of rotation from an input body and output the rotation so that the gear ratio of each gear position is equal to or greater than 1,

the shift mechanism includes a first planetary mechanism and a second planetary mechanism, and thereby forms a first shift path and a second shift path,

the first shift path includes a first planetary shift path that outputs the rotation from the input member at the first speed ratio without a speed change by the first planetary mechanism and without a speed change by the second planetary mechanism, and a second planetary shift path that outputs the rotation from the input member at the second speed ratio without a speed change by the first planetary mechanism and without a speed change by the second planetary mechanism,

the second shift path is shifted by another transmission mechanism, outputs rotation from the input member at a speed ratio larger than the first speed ratio and the second speed ratio, and is not shifted by the first planetary mechanism in the second shift path,

in the three consecutive gear positions among the five or more gear positions, when the ratio of the gear ratio of the maximum gear position to the gear ratio of the intermediate gear position is subtracted from the ratio of the gear ratio of the intermediate gear position to the gear ratio of the minimum gear position, the difference is both positive and negative in any of the three consecutive gear positions, and the absolute value of a value obtained by subtracting the other of the differences from one of the differences is 0.005 or more and 0.02 or less.

2. The bicycle derailleur according to claim 1,

the five or more shift stages include a smallest shift stage in the shift mechanism.

3. The bicycle derailleur according to claim 1 or 2,

the absolute value of the difference is 0.03 to 0.15 inclusive.

4. The bicycle derailleur according to claim 3,

the absolute value of the difference is 0.04 to 0.1.

5. The bicycle derailleur according to claim 1,

the difference is positive in any of the three consecutive shift stages.

6. The bicycle derailleur according to claim 1,

the shifting mechanism is an internally mounted shifting mechanism.

7. The bicycle derailleur according to claim 6,

further, the transmission device is provided with a hub for housing the built-in transmission mechanism.

8. A speed-changing device for a bicycle is provided,

the transmission mechanism includes four or more gear positions configured to increase a gear ratio stepwise, the transmission mechanism is configured to increase a speed of rotation from an input body and output the rotation so that the gear ratio of each gear position is equal to or greater than 1,

in the three consecutive gear positions among the four or more gear positions, when the ratio of the gear ratio of the maximum gear position to the gear ratio of the intermediate gear position is subtracted from the ratio of the gear ratio of the intermediate gear position to the gear ratio of the minimum gear position, the difference between any of the three consecutive gear positions is either positive or negative, the absolute value of the difference is both 0.03 or more and 0.15 or less, and the absolute value of the value obtained by subtracting the other of the differences from one of the differences is both 0.005 or more and 0.02 or less.

9. The bicycle derailleur according to claim 8,

the four or more shift stages include a smallest shift stage in the shift mechanism.

10. The bicycle derailleur according to claim 8 or 9,

the speed change mechanism includes five or more speed change stages configured to increase a speed change ratio stepwise,

the consecutive three shift stages are included in the five or more shift stages.

11. The bicycle derailleur according to claim 8,

the absolute value of the difference is 0.04 to 0.1.

12. The bicycle derailleur according to claim 8,

the difference is positive in any of the three consecutive shift stages.

13. The bicycle derailleur according to claim 8,

the shifting mechanism is an internally mounted shifting mechanism.

14. The bicycle derailleur according to claim 13,

15. A bicycle assist system includes:

a bicycle derailleur according to any one of claims 1 to 14; and

a motor for assisting a manual driving force.

16. The bicycle assist system as set forth in claim 15,

further comprises an operation part operated by human hand to operate the bicycle transmission,

the bicycle transmission changes a gear ratio of a bicycle according to an operation of the operating portion.