Bicycle gear shift control device, electrically assisted system and bicycle gear shift control method

Abstract

Bicycle gear shift control device (60) that controls a gear shift state of a bicycle transmission (24), comprising: a control device (66) that controls the gear-shift state of the transmission (24) according to an operation of a gear-shift control device (30) when a driving speed of a bicycle (10) is greater than a first speed (VA1), and the transmission (24) automatically controls itself to be in a first prescribed gear change state when the driving speed of the bicycle (10) becomes less than or equal to the first speed (VA1) and when a gear ratio (γ) of a current gear change state of the transmission (24) is greater than a preset gear ratio (γ1) of the first prescribed gear change state; After controlling the transmission (24) to be in the first prescribed gear change state, the control device (66), when the driving speed of the bicycle (10) becomes greater than a second speed (VA2), automatically controls the transmission (24) to a larger gear ratio (γ) than the gear ratio (γ1) of the first prescribed gear change state; characterized in that the control device (66) controls the transmission (24) to be in a second gear-change state corresponding to a gear ratio (γ) greater than the gear ratio (γ1) of the first prescribed gear-change state when the driving speed of the bicycle (10) becomes greater than the second speed (VA2) after it has controlled the transmission (24) to be in the first prescribed gear-change state; and wherein the gear ratio (γ) in the second gear change state is a gear ratio (γ) in the gear change state when the speed of the bicycle (10) becomes less than or equal to the first speed (VA1).

Description

TECHNICAL AREA

[0001] The present invention relates to a bicycle gear shift control device that controls the gear shift state of a bicycle gearbox, an electrically assisted system and a bicycle gear shift control method. STATE OF THE ART

[0002] When a rider begins pedaling a stationary bicycle, the manual driving force required at the start of pedaling can be reduced if the gear ratio is lower. For this reason, the bicycle gear-shifting control device of JP 2 617 059 B2 switches to a gear ratio suitable for starting pedaling from a standstill. SUMMARY OF THE INVENTION TASK TO BE SOLVED BY THE INVENTION

[0003] According to the JP 2 617 059 B2 bicycle gear-shifting control device, the rider can begin pedaling with a small amount of manual effort. However, there is a risk that the gear ratio, after being changed by the gear-shifting control device, might not be suitable once pedaling has begun. The JP 2 617 059 B2 bicycle gear-shifting control device does not change the gear ratio after pedaling has started. Therefore, the rider must perform an operation to change the gear ratio to one suitable for riding after starting to pedal. Consequently, there is a concern that changing the gear ratio will be inconvenient for the rider.

[0004] US 2002 / 0014366A1 discloses an automatic gear-shifting system that continuously shifts gears so that the correct gear is engaged for a measured bicycle speed. When the bicycle is stopped, the automatic gear-shifting system shifts to a lower gear.

[0005] JP H09 - 240 568 A discloses a control device for a gear-shifting system which provides the most efficient gear for operating an electric motor.

[0006] The object of the present invention is to provide a bicycle gear-shifting control device, an electrically assisted system and a bicycle gear-shifting control method that can reduce difficulties relating to changing the gear ratio when pedaling is restarted after the bicycle has been stopped. MEANS TO SOLVE THE PROBLEM

[0007] A bicycle gear-shifting control device according to the invention is a bicycle gear-shifting control device that controls a gear-shifting state of a bicycle transmission and that includes a control unit; the control unit controls the gear-shifting state of the transmission according to an operation of a gear-shifting control device when a bicycle's speed is greater than a first speed, and automatically controls the transmission to be in a first prescribed gear-shifting state when the bicycle's speed becomes less than or equal to the first speed and when a gear ratio of a current gear-shifting state of the transmission is greater than a preset gear ratio of the first prescribed gear-shifting state;After controlling the transmission to be in the first prescribed gear change state, if the bicycle's speed exceeds a second speed, the control device automatically controls the transmission to a higher gear ratio than the gear ratio of the first prescribed gear change state.

[0008] Furthermore, the control device controls the transmission to be in a second gear change state, corresponding to a gear ratio greater than the gear ratio of the first prescribed gear change state, if the bicycle's speed exceeds the second speed after controlling the transmission to be in the first prescribed gear change state.

[0009] Here, the gear ratio in the second gear change state is a gear ratio in the gear change state when the bicycle's speed becomes less than or equal to the first speed.

[0010] According to a preferred embodiment of the bicycle gear-shift control device, the control unit controls the transmission depending on the time when the bicycle's speed becomes greater than the second speed, after it has controlled the transmission to be in the first prescribed gear-shift state.

[0011] According to another preferred embodiment of the bicycle gear-shift control device, the control unit controls the transmission depending on the driving speed, if the driving speed of the bicycle becomes greater than the second speed, after it has controlled the transmission to be in the first prescribed gear-shift state.

[0012] According to one embodiment of the bicycle gear-shifting control device, the control unit further includes a prohibition setting unit that prohibits the transmission from being automatically controlled.

[0013] According to one embodiment of the bicycle gear-shift control device, the control device prohibits the transmission from being automatically controlled after it has controlled the transmission to be in the first prescribed gear-shift state if the bicycle's speed does not exceed the second speed within a prescribed time, until the bicycle's speed exceeds the second speed and the bicycle's speed again becomes less than or equal to the first speed.

[0014] According to one embodiment of the bicycle gear shift control device, the control unit controls the gear shift state of the transmission only depending on the operation of the gear shift control device, while the gear shift control device is prohibited from being controlled automatically.

[0015] According to one embodiment of the bicycle gear-shift control device, the control unit further includes a storage device that stores the gear-shift state of the transmission when the bicycle's speed becomes less than or equal to the initial speed.

[0016] According to one embodiment of the bicycle gear-shifting control device, the first speed and the second speed are 0 km per hour.

[0017] The electrically assisted bicycle according to a further embodiment of the present invention comprises the bicycle gear-shifting control device according to one of the paragraphs above and a motor that assists a manual drive force.

[0018] A bicycle gear-shift control method according to the present invention is a bicycle gear-shift control method that controls a gear-shift state of a bicycle transmission and that controls the gear-shift state of the transmission according to an operation of a gear-shift control device when a bicycle's speed is greater than a first speed; the control device automatically controls the transmission to be in a first prescribed gear-shift state when the bicycle's speed becomes less than or equal to the first speed and when a gear ratio of a current gear-shift state of the transmission is greater than a preset gear ratio of the first prescribed gear-shift state; after controlling the transmission to be in the first prescribed gear-shift state, the control device controlsWhen the bicycle's speed exceeds a second speed, the transmission automatically adjusts so that the gear ratio will be greater than the gear ratio of the first prescribed gear change state. Furthermore, in the bicycle gear-shift control method, the transmission is controlled to be in a second gear change state corresponding to a gear ratio greater than the gear ratio of the first prescribed gear change state when the bicycle's speed exceeds the second speed, after having controlled the transmission to be in the first prescribed gear change state. The gear ratio in the second gear change state is the same as the gear ratio in the gear change state when the bicycle's speed becomes less than or equal to the first speed. EFFECTS OF THE INVENTION

[0019] According to the present bicycle gear shift control device, electrically assisted system and bicycle gear shift control method, the difficulties associated with changing the gear ratio when pedaling is restarted after the bicycle has been stopped can be reduced. BRIEF DESCRIPTION OF THE DRAWINGS Fig. Figure 1 is a side view of a bicycle of one embodiment. Fig. Figure 2 is a block diagram showing an electrical structure of a control device of the embodiment. Fig. Figure 3 is a flowchart showing the steps of an automatic switching operation of the embodiment. Fig. Figure 4 is a timing diagram showing an execution state of the automatic switching operation of the embodiment. EXECUTIONAL FORMS FOR IMPLEMENTING THE INVENTION

[0020] As in Fig. As shown in Figure 1, the bicycle 10 comprises a frame 12, a handlebar grip 14, a front wheel 16, a rear wheel 18, a drive mechanism 20, a gearbox 24, a dynamo 26, a pedal force sensor 28, a gear shifting device 30, an assist mechanism 32, and a control unit 60 (see Figure 1). Fig. 2) and a battery 34.

[0021] The drive mechanism 20 comprises a left and a right crank arm 36, a crankshaft 38, a left and a right pedal 40, a front sprocket 42, a rear sprocket 44, and a chain 46. The left and right crank arms 36 are rotatably attached to the frame 12 via one end of the crankshaft 38. The pedals 40 are attached to the crank arms 36 so that they can rotate about a pedal shaft relative to the crank arms 36.

[0022] The front pinion 42 is coupled to the crankshaft 38. The front pinion 42 is designed to be coaxial with the crankshaft 38. The front pinion 42 can be coupled so that it does not rotate relative to the crankshaft 38, or this pinion can be coupled via a freewheel clutch so that the front pinion 42 also rotates forward when the crankshaft rotates forward. The rear pinion 44 is rotatably mounted around an axle shaft 18A of the rear wheel 18. The rear pinion 44 is coupled to the rear wheel 18 via the freewheel clutch (omitted from the drawings). The chain 46 is wound onto the front pinion 42 and the rear pinion 44. When the crank arm 36 rotates due to a manual driving force applied to the pedals 40, the rear wheel 18 is rotated by the front sprocket 42, the chain 46 and the rear sprocket 44.

[0023] The dynamo 26 is arranged around the axle shaft 16A of the front wheel 16. The dynamo 26 of the present embodiment is a hub dynamo. The dynamo 26 outputs a signal that corresponds to the rotational speed of the front wheel 16.

[0024] The pedal actuation force sensor 28 outputs a signal corresponding to the force exerted on the crankshaft 38. The force exerted on the crankshaft 38 correlates with the manual driving force applied to the pedal 40. Therefore, the pedal actuation force sensor 28 outputs a signal corresponding to the manual driving force. The pedal actuation force sensor 28 can be positioned along the power transmission path from the crankshaft 38 to the front sprocket 42, near the power transmission path, or on the crank arm 36 of the pedal 40. The pedal actuation force sensor 28 can be implemented using, for example, a strain sensor, a magnetostrictive sensor, an optical sensor, or a pressure sensor; any sensor can be used as long as it outputs a signal corresponding to the manual driving force applied to the pedal 40.

[0025] The gearshift control device 30 is attached to the handle 14. The gearshift control device 30 outputs a gearshift signal depending on an operation by the driver. The gearshift signal includes an upshift signal, indicating an upshift, and a downshift signal, indicating a downshift. Upshifting is shifting in the direction in which the gear ratio γ increases. Downshifting is shifting in the direction in which the gear ratio γ decreases.

[0026] The transmission 24 is implemented by an internal gearbox integrated with a hub. The transmission 24 comprises a plurality of shift positions and includes, for example, shift positions from first gear to third gear. The transmission 24 includes an actuator 48 (see Fig. 2) and a planetary gear mechanism (diagram omitted) controlled by the actuator 48. The actuator 48 is, for example, an electric motor. The actuator 48 changes the switching position of the bicycle 10, that is, the gear ratio γ, by changing the coupling state of the gears that form the planetary gear mechanism.

[0027] The support mechanism 32 comprises a motor 50 and a reduction gear (diagram omitted). The motor 50 is an electric motor that is rotated by electric current supplied by the battery 34. The rotation of the motor 50 is transmitted via the reduction gear to the front pinion 42. A freewheel clutch to prevent the motor from being rotated by the manual drive force when the crank arm 36 rotates forward may be provided between the motor 50 and the front pinion.

[0028] The support mechanism 32, which includes the motor 50, assists the manual drive force that rotates the front pinion 42 with the drive of the motor 50.

[0029] The design of the control unit 60 is described with reference to Fig. 2 described. The control unit 60 comprises a manual force calculation unit 62, an assistance control unit 64, a shift control unit 66, a speed calculation unit 68, a prohibition setting unit 70, and a storage device 72. The control unit 60 is connected by power lines to the dynamo 26, the pedal force sensor 28, the gear shift control unit 30, the actuator 48, the motor 50, and the battery 34. The control unit 60 and the dynamo 26, the pedal force sensor 28, the gear shift control unit 30, the actuator 48, the motor 50, and the battery 34 can communicate with each other via power line communication. The control unit 60 controls the assistance state of the assistance mechanism 32 and the gear shift state of the transmission 24.

[0030] The manual force calculation unit 62 calculates the manual drive force FA based on a signal output by the pedal actuation force sensor 28. The support control unit 64 drives the motor 50 based on the manual drive force FA. The support mechanism 32 thus provides assistance corresponding to the manual drive force FA. The manual force calculation unit 62 and the support mechanism 32 together form the electrically assisted system.

[0031] The shift control unit 66 drives the actuator 48 based on a signal output by the gear shift control unit 30. If an upshift signal is received, the shift control unit 66 changes the gear shift state of the transmission 24 to a shift position on the side where the gear ratio γ increases. If a downshift signal is received, the shift control unit 66 changes the gear shift state of the transmission 24 to a shift position on the side where the gear ratio γ decreases. The shift control unit 66 will not shift gears if an upshift signal is received in a shift position with the maximum gear ratio γ or if a downshift signal is received in a shift position with the minimum gear ratio γ.

[0032] If the speed VA of the bicycle 10 is greater than the first speed VA1, the shift control device 66 controls the transmission 24 according to the operation of the gear shift control device 30. If, on the other hand, the speed VA becomes less than or equal to the first speed VA1, an automatic shift operation is carried out to control the transmission 24 based on the speed VA.

[0033] The speed calculation unit 68 calculates the speed VA, which is the travel speed of the bicycle 10, based on a signal output by the dynamo 26. The output from the dynamo 26 varies periodically depending on the rotation of the front wheel 16 (see Fig. 1) For this reason, the speed calculation unit 68 calculates the speed VA based on the number of rotations of the front wheel 16 per a prescribed time period (see Fig. 1) from the 26th edition of Dynamo.

[0034] The prohibition setting unit 70 prevents the gearbox 24 from being automatically controlled based on the speed of the bicycle 10. The control unit 60 controls the gear-shift state of the gearbox 24 only depending on the operation of the gear-shift control device 30, while automatic control of the gearbox 24 by the prohibition setting unit 70 is prohibited.

[0035] The automatic switching operation, which is carried out by the switching control device 66, is described with reference to Fig. 3 explained. In step S11, the switching control unit 66 determines whether the bicycle 10 has transitioned from a moving state to a stationary state. More precisely, the switching control unit 66 determines whether the bicycle's speed VA has changed from a value greater than the initial speed VA1 to less than or equal to the initial speed VA1. If the control unit determines that the speed VA is greater than the initial speed VA1, the current step is terminated, and the determination step from step S11 is repeated after a prescribed period. The initial speed VA1 is a value used to determine whether the bicycle 10 has stopped; therefore, for example, 0 km / h can be used.

[0036] If the shift control unit 66 determines in step S11 that the speed VA has become less than or equal to the initial speed VA1, a determination is made in step S12 as to whether the gear ratio γ corresponding to the gear change state of the transmission 24 at that time is greater than an initial gear ratio γ1 or not. If the control unit determines that the speed VA is greater than the initial speed VA1, the current step is terminated, and the determination step from step S11 is repeated after a prescribed period. The initial gear ratio γ1 is a gear ratio γ corresponding to a low gear; for example, the minimum gear ratio γ can be used.

[0037] However, if the shift control unit 66 determines that the gear ratio γ is greater than the initial gear ratio γ1 at that time, the current gear shift state at that time is stored in the storage device 72 in step S13, and the automatic control of the transmission 24 is enabled by the prohibition setting unit 70. In other words, when the speed VA of the bicycle becomes less than or equal to the initial speed VA1, the prohibition setting unit 70 disables the automatic control. Here, "at that time" means when the speed VA becomes less than or equal to the initial speed VA1. The gear shift state is, for example, the shift position or the gear ratio γ. Then, in step S14, the actuator 48 is controlled so that the gear shift state of the transmission 24 will be in a prescribed initial gear shift state.This changes the translation ratio γ to the first translation ratio γ1.

[0038] Next, in step S15, the shift control unit 66 determines whether the bicycle 10 has transitioned from a stationary state to a moving state. More precisely, the shift control unit 66 determines whether the bicycle's speed VA has become greater than the second speed VA2. If the shift control unit determines that the speed VA has become greater than or equal to the second speed VA2, in step S16 the gear change state of the transmission 24 is controlled such that the gear ratio γ will become greater than a first gear ratio γ1. The second speed VA2 is a value used to determine whether the bicycle 10 has restarted moving; for example, a prescribed speed of less than or equal to 0 km / h can be used.

[0039] Next, in step S17, the shift control unit 66 determines whether the gear change state of the transmission 24 corresponds to the gear change state stored by the storage device 72 in step S13. If the gear change state differs from the gear change state stored by the storage device 72 in step S13, the gear change state is controlled so that the gear ratio γ increases again in step S16, after which the determination step from step S17 is repeated. If the shift control unit 66 determines that the gear change state corresponds to the gear change state stored in step S13, the automatic control by the prohibition setting unit 70 is prohibited in step S19, and the current step is terminated.When the speed VA of the bicycle becomes less than or equal to the initial speed VA1, the prohibition setting unit 70 lifts the prohibition of automatic control with the step from step S13.

[0040] If the switching control unit 66 determines in step S15 that the speed VA is less than or equal to the second speed VA2, a timer equipped by the control unit 66 will be used to determine whether the time TX, which is a prescribed time, has elapsed since the speed VA became less than or equal to the first speed VA1. If the switching control unit 66 determines that the time TX has not elapsed, the determination step of step S15 will be repeated. However, if the switching control unit 66 determines that the time TX has elapsed, the automatic control by the prohibition setting unit 70 in step S19 will be prohibited, and the current step will be terminated. For example, a prescribed time of greater than or equal to 1 hour can be used as the time TX.In this case, automatic control of the transmission 24 is prohibited until the speed VA becomes greater than the second speed VA2 and until the speed becomes less than or equal to the first speed VA1; in other words, until an affirmative determination is made in step S11 of the subsequent automatic shifting operations.

[0041] An example of an execution mode of the automatic switching operation is given with reference to the solid line in Fig. 4 explains that if the stopping time, which is the elapsed time from the time when the speed VA of the bicycle 10 becomes less than or equal to the first speed VA1, until the time when the speed becomes greater than the second speed VA2, is shorter than the time TX.

[0042] Time t10 represents the time at which the velocity VA changes from a state greater than the initial velocity VA1 to a state less than or equal to the initial velocity VA1. Automatic control is permitted at this time. If the gear ratio γ is greater than the initial gear ratio γ1 at this time, the gear change state is continuously modified after time t10, and the gear ratio γ is changed to the initial gear ratio γ1.

[0043] Time t11 indicates the time before time TX has elapsed since time t10 and when the velocity VA becomes greater than the second velocity VA2. The gear shift state is continuously changed after time t11. This changes the gear shift state to a gear shift state corresponding to the gear ratio γ that was the gear ratio γ at time t10.

[0044] Time t12 indicates a point in time at which the gear ratio γ corresponds to the gear ratio γ at time t10. Automatic control is prohibited at this point. Therefore, the transmission 24 is controlled based on the output of the gear-shift control unit 30 after time t12.

[0045] An example of an execution mode of the automatic switching operation is given with reference to the double-dash-dotted line in Fig.4 explains when the stop time is longer than the time TX.

[0046] Time t13 indicates the point in time when speed VA is less than or equal to the second speed VA2, and when time TX has elapsed since time t10. Automatic control is prohibited at this time. With this setup, the transmission 24 is controlled based on the output of the gear-shift control unit 30 after time t13.

[0047] The control unit 60 has the following effects. (1) The control unit 60 automatically controls the transmission 24 based on the fact that the speed VA has become less than or equal to the first speed VA1. Therefore, the problem of operating the gear-shifting device 30 to facilitate manual power transfer when the rider begins to pedal 40 is eliminated. After pedaling 40 begins, it is preferable to increase the gear ratio γ in response to the increase in the speed VA of the bicycle 10. The control unit 60 controls the transmission 24 so that the gear ratio γ increases when the speed VA becomes greater than the second speed VA2. Therefore, the load associated with changing the gear ratio γ can be reduced when pedaling resumes after the bicycle 10 has come to a stop. (2) The control unit 60 controls the transmission 24 so that the gear ratio γ becomes the gear ratio γ of the first speed VA1 when the speed VA becomes less than or equal to the first speed VA1, or when the speed VA becomes greater than the second speed VA2. Therefore, the transmission 24 is automatically controlled to return to the same gear ratio γ as before the bicycle 10 stopped. This reduces the effort required for the rider to change the gear ratio γ back to a gear ratio γ suitable for riding. (3) There are cases where the stopping time before riding the bicycle 10 is resumed is long, for example, due to parking. In this case, there are instances where the rider changes or the speed VA desired by the rider is different when the pedal 40 is operated again. Therefore, if the stopping time is long, there is a greater risk, compared to a temporary stop, that the gear ratio γ appropriate for riding the bicycle 10 will differ from the gear ratio γ before the stop.

[0048] If the speed VA does not exceed the second speed VA2 within time TX, the control unit 60 prevents the transmission 24 from being automatically controlled until the speed VA is again less than or equal to the first speed VA1. Therefore, after pedal 40 is actuated, the gear ratio γ of the bicycle 10 is not automatically changed to the gear ratio γ corresponding to the gear change state stored in the memory device 72 at the time of starting. This reduces the risk of an automatic change to a gear ratio γ that the rider does not want.

[0049] (4) Depending on the rider's leg strength or the riding environment, etc., there are cases where the rider is subjected to excessive strain if the gear ratio γ is increased after pedaling 40 has begun. The bicycle 10 includes a motor 50. For this reason, the manual driving force can be assisted when riding the bicycle 10 is resumed. This prevents the rider from being subjected to excessive strain.

[0050] The specific form that this control device can assume is not limited to the forms described in the embodiment described above. This control device can assume various forms that differ from the embodiment described above. The modified example of the embodiment described above, described below, is an example of the various forms that this control device can assume. • The determination step of step S18 of the automatic shift operation can be omitted. In this case, if the speed VA becomes greater than the second speed VA2, regardless of the duration of the stop time, the transmission 24 is automatically controlled until the gear change state corresponds to the gear change state stored by the storage device 72. • The determination step of step S17 of the automatic shift operation can also be omitted. In this case as well, the shift control unit 66 will control the transmission 24 so that the gear ratio γ increases until it reaches a prescribed gear ratio γ or a prescribed shift position. For this reason, the load associated with the change in the gear ratio γ can be reduced when pedaling resumes after the bicycle 10 has come to a stop. • In step S16 of the automatic shift operation, the gear shift state of the transmission 24 can be controlled as a function of time. For example, the gear ratio γ is increased based on the fact that the time elapsed since the speed VA became greater than the second speed VA2 exceeds the set time. If the gear shift state is changed by repeating step S16, the shift control unit 66 causes the transmission 24 to shift at intervals T before the next shift. This interval T can be preset, set by the rider, or varied depending on the bicycle's speed. For example, if the interval T is set by the rider, a bicycle computer is connected to the control unit 60, and a setting switch provided on the bicycle computer is used.In the case of varying the interval T depending on the speed VA, the switching control device 66 can further control the interval T by using a correlation table or a function of the speed and the interval T, so that the interval T becomes smaller as the speed VA increases. • In step S16 of the automatic shift operation, the gear change state of the transmission 24 can be controlled depending on the speed VA. For example, the gear ratio γ is increased based on the fact that the speed VA has become greater than the set speed. For example, the shift control unit 66 controls the transmission 24 depending on the speed VA by using a correlation table or a function of the speed VA and the gear ratio γ. • The first speed VA1 can be changed to a speed VA at which the bicycle is scheduled to come to a stop within a given time period. In this case, the control of the gear shift state is performed in step S14 before the bicycle comes to a complete stop. For the speed VA at which the stop is scheduled, a value close to 0 km / h or a value greater than 0 km / h can be used, for example, 3 km / h. Regarding the second speed VA2, a value greater than 0 km / h can be used, for example, 3 km / h. By using a value greater than 0 km / h for the second speed VA2, shifting due to back-and-forth oscillation of the bicycle while stationary can be suppressed. It is also possible to have the first speed VA1 and the second speed VA2 be different values. • A rotation sensor that outputs a signal corresponding to the rotational speed of the front wheel 16, the rear wheel 18, or the crankshaft 38 can be used in place of the dynamo 26, and the speed VA can be calculated based on the output of the rotation sensor. In short, any sensor can be used as long as it outputs a signal corresponding to the speed of the bicycle 10. • A control unit that allows the driver to change the setting for prohibiting and allowing the execution of the automatic shift operation can also be added. • A control unit can also be added, allowing the driver to change the setting for prohibiting and allowing the execution of steps S15-S18 in step S13 of the automatic shift operation. • The support mechanism 32 can also be omitted. • The gearbox 24 can be converted into a continuously variable gearbox, which can also continuously change the gear ratio γ. Furthermore, the gearbox can be converted into an external gearbox. In short, any gearbox can be used as long as it can change the gear ratio γ of the bicycle 10. • The control unit 60 can be connected to at least one of the dynamo 26, the pedal actuation force sensor 28 or the gear shift control device 30 via wireless communication. • The control unit 60 can be connected to the dynamo 26, the pedal actuation force sensor 28, the gear shift control device 30, the actuator 48, the motor 50 and the battery 34 via normal wired communication instead of wireless communication.

Claims

[1] Bicycle gear shift control device (60) which controls a gear shift state of a bicycle transmission (24), comprising: a control device (66) that controls the gear-shift state of the transmission (24) according to an operation of a gear-shift control device (30) when a driving speed of a bicycle (10) is greater than a first speed (VA1), and the transmission (24) automatically controls itself to be in a first prescribed gear change state when the driving speed of the bicycle (10) becomes less than or equal to the first speed (VA1) and when a gear ratio (γ) of a current gear change state of the transmission (24) is greater than a preset gear ratio (γ1) of the first prescribed gear change state; After controlling the transmission (24) to be in the first prescribed gear change state, the control device (66), when the driving speed of the bicycle (10) becomes greater than a second speed (VA2), automatically controls the transmission (24) to a larger gear ratio (γ) than the gear ratio (γ1) of the first prescribed gear change state; characterized by , that the control device (66) controls the transmission (24) to be in a second gear-change state corresponding to a gear ratio (γ) greater than the gear ratio (γ1) of the first prescribed gear-change state when the driving speed of the bicycle (10) becomes greater than the second speed (VA2) after it has controlled the transmission (24) to be in the first prescribed gear-change state; and wherein the gear ratio (γ) in the second gear change state is a gear ratio (γ) in the gear change state when the speed of the bicycle (10) becomes less than or equal to the first speed (VA1). [2] Bicycle gear shift control device (60) according to claim 1, wherein the control device (66) controls the transmission (24) as a function of time when the driving speed of the bicycle (10) becomes greater than the second speed (VA2) after it has controlled the transmission (24) to be in the first prescribed gear shift state. [3] Bicycle gear shift control device (60) according to claim 1, wherein the control device (66) controls the transmission (24) depending on the driving speed when the driving speed of the bicycle (10) becomes greater than the second speed (VA2), after it has controlled the transmission (24) to be in the first prescribed gear shift state. [4] Bicycle gear shift control device (60) according to one of claims 1 to 3, wherein the control device (66) further comprises a prohibition setting unit (70) which prohibits the transmission (24) from being automatically controlled. [5] Bicycle gear-shift control device (60) according to one of claims 1 to 4, wherein the control device (66) prevents the transmission (24) from being automatically controlled after it has controlled the transmission (24) to be in the first prescribed gear-shift state if the driving speed of the bicycle (10) does not exceed the second speed (VA2) within a prescribed time, until the driving speed of the bicycle (10) exceeds the second speed (VA2) and the driving speed (VA) of the bicycle (10) again becomes less than or equal to the first speed (VA1). [6] Bicycle gear shift control device (60) according to claim 4, wherein the control unit (66) controls the gear shift state of the transmission (24) only depending on the operation of the gear shift control device (30), while the gear shift control device (30) is prohibited from being controlled automatically. [7] Bicycle gear shift control device (60) according to claim 1, wherein the control device (66) further comprises a storage device (72) which stores the gear shift state of the transmission (24) when the driving speed (VA) of the bicycle (10) becomes less than or equal to the first speed (VA1). [8] Bicycle gear shift control device (60) according to any one of claims 1 to 7, wherein the first speed (VA1) and the second speed (VA2) are 0 km per hour. [9] Electrically assisted system, comprising: the bicycle gear shift control device (60) according to one of claims 1 to 8, and a motor (50) that assists a manual drive force (FA). [10] Bicycle gear shift control method, which controls a gear-change state of a bicycle transmission (24), and controls the gear-change state of the transmission (24) according to an operation of a gear-change control device (30) when a driving speed (VA) of a bicycle (10) is greater than a first speed (VA1), and the transmission (24) automatically controls it to be in a first prescribed gear-change state when the driving speed of the bicycle (10) becomes less than or equal to the first speed (VA1) and when a gear ratio (γ) in a current gear-change state of the transmission (24) is greater than a preset gear ratio (γ1) of the first prescribed gear-change state, wherein, after controlling the transmission (24) to be in the first prescribed gear-change state, when the driving speed of the bicycle (10) becomes greater than a second speed (VA2), the transmission (24) is automatically controlled so that the gear ratio (γ) will be greater than the gear ratio (γ1) of the first prescribed gear-change state; characterized by, that the bicycle gear-shift control method controls the transmission (24) to be in a second gear-shift state corresponding to a gear ratio (γ) greater than the gear ratio (γ1) of the first prescribed gear-shift state when the driving speed of the bicycle (10) becomes greater than the second speed (VA2) after it has controlled the transmission (24) to be in the first prescribed gear-shift state; and wherein the gear ratio (γ) in the second gear change state is a gear ratio (γ) in the gear change state when the speed of the bicycle (10) becomes less than or equal to the first speed (VA1).

Images