Bicycle motor control system

[Technical Field]

0001The present invention relates to a bicycle motor control system, and in particular to a bicycle motor control system for controlling a motor for assisting rotation of a bicycle wheel.

[Background Art]

0002There are known in the art power-assisted bicycles, in which human-powered driving of a bicycle is assisted by an electric motor (for example, see Patent Citation 1). In a conventional power-assisted bicycle of such description, when the rider selects the assist mode, the driving force applied by the rider is assisted by an electric motor. In contrast, when the rider selects the regenerative charging mode, electrical power obtained from the electric motor is fed to a battery, whereby the battery is regeneratively charged.

[Prior Art Citation]

0003<b>[Patent Citation 1]</b><patcit id="pcit0001" dnum="JP2005304283A"><text>JP-A 2005-304283</text></patcit>

[Disclosure of the Invention]

[Problems the Invention Is Intended to Solve]

0004In a conventional power-assisted bicycle, in a circumstance in which, e.g., the amount of charge in the battery becomes insufficient, the control system for controlling the operation mode of the motor becomes unable to issue various types of commands, and the operation mode of the motor cannot be switched. Therefore, in a circumstance in which the amount of charge in the battery becomes insufficient, or in similar circumstances, there is a possibility that the operation mode of the motor will not have been set to the appropriate operation mode.

0005An object of the present invention is to provide a system in which the operation mode of the motor can be set to the appropriate operation mode.

[Means for Solving These Problems]

0006A bicycle motor control system according to a first aspect of the present invention is a system for controlling a motor for assisting rotation of a bicycle wheel.

0007The motor control system comprises a communication part for the motor, and a first mode switching part. The communication part for the motor can perform power line communication in relation to an electrical component that is mountable on a bicycle and that can change an operation mode of the motor.

0008The first mode switching part can be operated either by electrical power supplied via a power line through which the communication part performs power line communication, or by electrical power obtained from a generator. The first mode switching part switches the operation mode of the motor according to a state of communication with the electrical component, from a driving mode, in which the motor is capable of assisting rotation of the bicycle wheel, to a power generating mode, in which the motor outputs electrical power that has been generated using rotation of the bicycle wheel.

0009In power line communication, the power line and a communication line share a common line. An information signal having a higher frequency than a power signal is impressed on the power signal, thereby making it possible to communicate both electrical power and information. Therefore, in a circumstance in which the power signal is lost, i.e., in a circumstance in which supply of electrical power is stopped, electrical power communication itself is discontinued. In other words, if power line communication is being performed, it is possible to judge that electrical power and information are being supplied.

0010In the present invention, the first mode switching part thereby dynamically switches the operation mode of the motor from the driving mode to the power generating mode according to the state of communication with the electrical component, and therefore the operation mode of the motor can be set as appropriate.

0011A bicycle motor control system according to a second aspect of the present invention is the system according to the first aspect, further comprising a rotation detecting part for detecting a state of rotation of the wheel. The first mode switching part switches the operation mode of the motor from the driving mode to the power generating mode according to the state of communication with the electrical component and the state of rotation of the wheel. In this circumstance, the first mode switching part uses the state of rotation of the wheel to judge the state of generation of power necessary for switching the operation mode, i.e., the state of power generation of the motor. The operation mode of the motor can thereby be switched from the driving mode to the power generating mode as appropriate.

0012A bicycle motor control system according to a third aspect of the present invention is the system according to the first or the second aspect, wherein in a circumstance in which communication with the electrical component is disabled, the first mode switching part switches the operation mode of the motor from the driving mode to the power generating mode. According to the aspect described above, in a circumstance in which communication with the electrical component is disabled, i.e., in a circumstance in which supply of electrical power to the motor is stopped, the operation mode of the motor can be dynamically switched from the driving mode to the power generating mode, and the operation mode of the motor can therefore be set as appropriate.

0013A bicycle motor control system according to a fourth aspect of the present invention is the system according to any of the first through third aspects, wherein, in a circumstance in which communication with the electrical component is disabled and the speed of rotation of the wheel is greater than a predetermined speed of rotation, the first mode switching part switches the operation mode of the motor from the driving mode to the power generating mode.

0014According to the aspect described above, in a circumstance in which communication with the electrical component is disabled, e.g.., in a circumstance in which the supply of electrical power to the motor is stopped and the speed of rotation of the wheel is greater than the predetermined speed of rotation, the operation mode of the motor is dynamically switched from the driving mode to the power generating mode. In other words, in an a circumstance in which, e.g., operation in the power generating mode using electrical power from the motor can be performed in a stable manner, the operation mode of the motor is dynamically switched from the driving mode to the power generating mode. The operation mode of the motor can therefore be switched even more appropriately.

0015A bicycle motor control system according to a fifth aspect of the present invention is the system according to any of the first through fourth aspects, wherein the communication part for the motor can be actuated by electrical power generated by the motor.

0016In such a circumstance, since the communication part for the motor is actuated by electrical power generated by the motor, processing and control in relation to communication can be performed even in a circumstance in which power is not supplied from an external source.

0017A bicycle motor control system according to a sixth aspect of the present invention is the system according to any of the first through fifth aspects, further comprising a stoppage time calculating part for calculating the time for which communication with the electrical component is stopped. According to the aspect described above, the first mode switching part switches the operation mode of the motor from the driving mode to the power generating mode in a circumstance in which communication with the electrical component is disabled for a period that is equal to or greater than a predetermined time. In such a circumstance, the operation mode of the motor is switched from the driving mode to the power generating mode in a circumstance in which communication with the electrical component is disabled for the predetermined time or longer. It is thereby possible to restrict the operation mode from switching in a circumstance in which supply of electrical power has stopped temporarily.

0018A bicycle motor control system according to a seventh aspect of the present invention is the system according to any of the first through sixth aspects, wherein a second mode switching part switches the operation mode of the motor from the power generating mode to the driving mode based on a mode switching signal from the electrical component that is actuated using electrical power that has been charged by a power source that is different from the motor. In such a circumstance, the electrical component mentioned above is actuated using electrical power from the power source that is different from the motor, and the operation mode of the motor can be dynamically switched from the power generating mode to the driving mode based on the mode switching signal from the electrical component.

0019A bicycle motor control system according to an eighth aspect of the present invention is the system according to the seventh aspect, further comprising a charge amount monitoring part for monitoring an amount of charge in the power source. The second mode switching part switches the operation mode of the motor from the power generating mode to the driving mode in a circumstance in which the amount of charge in the power source becomes equal to or greater than a predetermined value. In such a circumstance, since the operation mode of the motor is switched from the power generating mode to the driving mode in a circumstance in which the amount of charge in the battery becomes equal to or greater than the predetermined value, rotation of the bicycle wheel can be assisted in a reliable manner after the operation mode has been switched.

0020A bicycle motor control system according to a ninth aspect of the present invention is the system according to the seventh or eighth aspects, wherein the second mode switching part switches the operation mode of the motor from the power generating mode to the driving mode in a circumstance in which communication is possible, for a predetermined time, between the communication part for the motor and a communication part for communicating with the electrical component. In such a circumstance, since the operation mode of the motor is switched from the power generating mode to the driving mode in a circumstance in which communication between the communication part for the motor and the communication part for communicating with the electrical component is maintained over a predetermined time, the operation mode of the motor can be dynamically switched from the power generating mode to the driving mode when the state of communication with the electrical component, i.e., the state of supply of electrical power to the motor, is stable.

0021A bicycle motor control system according to a tenth aspect of the present invention is a system according to any of the seventh through ninth aspects, wherein the second mode switching part switches the operation mode of the motor, based on the state of rotation detected by the rotation detecting part, from the power generating mode to the driving mode in a circumstance in which the number of rotations of the wheel reaches a predetermined number of rotations or in a circumstance in which the distance over which the bicycle travels reaches a predetermined distance. In such a circumstance, since the operation mode of the motor is switched from the power generating mode to the driving mode in a circumstance in which the number of rotations of the wheel reaches a predetermined number of rotations or in a circumstance in which the distance over which the bicycle travels reaches a predetermined distance, the operation mode of the motor can be switched from the power generating mode to the driving mode in a state in which the supply of electrical power to the motor is stable. Specifically, electrical power can be supplied to the motor in a reliable manner.

0022A bicycle motor control system according to an eleventh aspect of the present invention is the system according to any of the first through tenth aspects, wherein the first mode switching part is provided to a bicycle hub within which the motor is incorporated, and the operation mode can be switched at the bicycle hub.

[Effect of the Invention]

0023According to the present invention, the operation mode of the motor can be dynamically switched, according to a state of communication with the electrical component, from the driving mode, in which the motor is capable of assisting rotation of the bicycle wheel, to the power generating mode, in which the motor outputs electrical power that has been generated using rotation of the bicycle wheel.

[Brief Description of the Drawings]

0024<ul id="ul0001" list-style="none" compact="compact"><li><figref idref="f0001">FIG. 1</figref> is a right-side view of a bicycle in which an embodiment of the present invention is used;</li><li><figref idref="f0002">FIG. 2</figref> is a circuit block diagram of an electrical circuit part;</li><li><figref idref="f0003">FIG. 3</figref> is a function block diagram of a motor control system;</li><li><figref idref="f0004">FIG. 4</figref> is a flow of the motor control system (first embodiment);</li><li><figref idref="f0005">FIG. 5</figref> is a flow of the motor control system (second embodiment);</li><li><figref idref="f0006">FIG. 6</figref> is a flow of the motor control system (third embodiment);</li><li><figref idref="f0007">FIG. 7</figref> is a flow of the motor control system (fourth embodiment);</li><li><figref idref="f0008">FIG. 8</figref> is a flow of the motor control system (fifth embodiment);</li><li><figref idref="f0009">FIG. 9</figref> is a flow of the motor control system (sixth embodiment); and</li><li><figref idref="f0010">FIG. 10</figref> is a flow of the motor control system (seventh embodiment).</li></ul>

[Best Mode for Carrying Out the Invention]

<Overall configuration of bicycle>

0025In <figref idref="f0001">FIG. 1</figref>, a bicycle in which an embodiment of the present invention is used is a power-assisted bicycle in which human-powered driving is assisted by a hub 10 within which the motor is incorporated. The bicycle comprises a frame 101 having a frame body 102 and a front fork 103, a handle part 104, a driving part 105, a front wheel 106f, a rear wheel 106r, a front brake device 107f and a rear brake device 107r, a forward-illuminating light 23, and a rear light 24. The front fork 103 is mounted on a front part of the frame body 102 so as to be capable of swinging about a diagonal axis. The front brake device 107f and the rear brake device 107r respectively come into contact with, and apply braking to, a front rim 121f and a rear rim 121r of the front wheel 106f and the rear wheel 106r.

0026A variety of parts including a saddle 111 and the handle part 104 are attached to the frame 101. The drive part 105 comprises a crank shaft 116 supported by a hanger part of the frame body 102 in a rotatable manner; a gear crank 118a and a left crank (not shown) secured to both ends of the crank shaft 116; a chain 119 provided around the gear crank 118a; a gear 109 mounted on a rear hub 110 of the rear wheel 106r; a front derailleur 108f; and a rear derailleur 108r.

0027In the front derailleur 108f, the chain 119 is engaged around one of, e.g., three sprockets mounted on the gear crank 118a. In the rear derailleur 108r, the chain 119 is engaged around one of, e.g., nine sprockets of the gear 109 attached to the rear hub 110. Both of the front derailleur 108f and the rear derailleur 108r are electrically driven. Each of the derailleurs comprises an electrical actuator, a stage sensor for detecting the current shift stage, and a derailleur control part for controlling the electrical actuator and the stage sensor (not shown). A handlebar 115 is provided with a shift switch for issuing a shift command. The derailleur control part controls the electrical actuator according to operation of the shift switch. In the present embodiment, the front derailleur 108f and the rear derailleur 108r are electrically driven. However, the front derailleur 108f and the rear derailleur 108r may also be configured so as to be linked to a shift lever by a wire, wherein the wire is pulled using the shift lever, thereby driving the derailleur so that the gear is shifted.

0028A rear carrier 112 is attached to an upper rear part of the frame body 102. A rear carrier unit 13 is mounted on the rear carrier 112. The rear carrier unit 13 includes an overall control part 12, which is an electrical component that is capable of changing the operation mode of a main motor body 10a. The overall control part 12 controls other electrical components 20 installed on the bicycle, including the hub 10 within which the motor is incorporated (see <figref idref="f0003">FIG. 3</figref> for other electrical components 20).

0029The rear carrier unit 13 is detachably installed with a power-storing part 14, which functions as a power source for the hub 10 within which the motor is incorporated, the overall control part 12, the forward-illuminating light 23, and other electrical components 20. The power-storing part 14 includes a storage battery. The storage battery includes, e.g., a nickel-hydrogen battery, a lithium ion battery, or another battery. The rear light 24 is integrally attached to the power-storing part 14.

0030The overall control part 12 can be actuated using electrical power charged in the power-storing part 14. The overall control part 12 primarily comprises a CPU (i.e., central processing unit), a ROM (i.e., read-only memory), and a RAM (i.e., random access memory) (not shown). For example, the CPU reads a command relating to control from the ROM and issues the command externally. The CPU also reads a command relating to calculation from the ROM and issues the command externally. In such a circumstance, based on the command from the CPU, a variety of data is read from the ROM and stored in the RAM. The CPU then uses the data stored in the RAM to perform a variety of processes. The CPU then issues a variety of commands externally according to the results of the processes.

0031The overall control part 12 has an overall communication part 78 (i.e., a communication part for communicating with an electrical component). The overall communication part 78 transmits/receives electrical power signals and information signals via a power line 70 described further below (see <figref idref="f0002">FIGS. 2</figref> and <figref idref="f0003">3</figref>) using, e.g., PLC (power line communication).

0032The handle part 104 has a handle stem 114 secured to an upper part of the front fork 103, and a bar-handle-shaped handlebar 115 secured to the handle stem 114. A left brake lever 16f and a right brake lever 16r are mounted on both ends of the handlebar 115. A display unit 18 and the forward-illuminating light 23 are mounted on a center part of the handlebar 115. The display unit 18 is capable of displaying the operation mode, such as the assist mode or the regenerative braking mode.

0033The other electrical components 20 include, e.g., the display unit 18, the forward-illuminating light 23, the rear light 24, and other components. The other electrical components 20 are connected to each other by, e.g., PLC through a power line 70. Each of the other electrical components 20 transmits/receives electrical signals and information signals. Also, the electrical components 20 have a function similar to that of the overall control part 12.

0034A hub of the front wheel 106f of the bicycle forms the hub 10 within which the motor is incorporated. The hub 10 within which the motor is incorporated is mounted at a distal end of the front fork 103 and is used for assisting human power. The hub 10 within which the motor is incorporated includes a motor (hereafter referred to as the main motor body 10a). The main motor body 10a is realized using, e.g., a 3-phase brushless DC motor. As shown in <figref idref="f0002">FIG. 2</figref>, the hub 10 within which the motor is incorporated has a hub axle 15, a motor case 17 mounted on the hub axle 15, and an electrical circuit part 19 arranged within the motor case 17.

0035The mechanical configuration of the motor-incorporating hub may be an inner rotor motor or an outer rotor motor. The motor-incorporating hub may also comprise a planetary gear mechanism for reducing the rate of rotation from the main motor body 10a and transmitting the rotation to the hub shell. The motor-incorporating hub may also have a configuration in which the planetary gear system is not provided and the rotor is directly connected to the hub shell.

<Electrical circuit part>

0036The electrical circuit part 19 performs a drive control of the hub 10 within which the motor is incorporated, and performs auxiliary control of electrical power supplied to the electrical components 20. The electrical circuit part 19 has the function of a DC-AC inverter for performing switching on a DC current supplied from the power-storing part 14 and converting the DC current into an AC current. The electrical circuit part 19 also has a rotation sensor function for detecting, from the frequency of the switching described above, at least one of the number of rotations and the speed of rotation of the hub 10 within which the motor is incorporated.

0037The electrical circuit part 19 also has a regenerative driving function in which a control is performed by the overall control part 12 to vary the regenerative braking ratio when the hub 10 within which the motor is incorporated is used to perform regenerative braking. The electrical circuit part 19 also has a power generating mode, in which the main motor body 10a arranged within the hub 10 within which the motor is incorporated is used as a generator, and electrical power, which can operate the overall control part 12 and/or the other electrical components 20, is outputted.

0038The output of the power-storing part 14 varies according to the state of power storage. For example, the power-storing part 14 outputs the maximum voltage when in a fully charged state. The output voltage decreases from the maximum voltage to the minimum voltage as the amount of charge in the power-storing part 14 decreases. For example, as the amount of charge in the power-storing part 14 decreases, the output voltage decreases from 24 V (i.e., maximum voltage) to 18 V (i.e., minimum voltage). When power stored in the power-storing part 14 has been depleted or the amount of power stored falls to a predetermined level or below, output from the power-storing part 14 is stopped. Here, the power-storing part 14 is connected to the overall control part 12, and supply of electrical power from the power-storing part 14 is controlled by the overall control part 12.

0039The electrical circuit part 19 has a function of a motor driving circuit for driving the main motor body 10a, as well as a function of an electrical power generating circuit for generating electrical power from the main motor body 10a. The electrical circuit part 19 comprises a plurality of (e.g., six) field effect transistors (FETs) installed on a circuit board secured to the interior of a main case body of the hub 10 within which the motor is incorporated, and other electronic components including a control element 46 for the motor. The electrical circuit part 19 performs auxiliary control of electrical power supplied to the overall control part 12 and/or the other electrical components 20. The electrical circuit part 19 is able to operate under electrical power from the main motor body 10a provided to the bicycle. The electrical circuit part 19 is able to convert electrical power generated by the main motor body 10a to a voltage or a current capable of operating the electrical components 20, and supply the converted electrical power to the overall control part 12 and/or the electrical components 20. The electrical circuit part 19 comprises a control part 71 for the motor, and a communication part 72 for the motor, shown in <figref idref="f0003">FIG. 3</figref> and described further below.

<Configuration of motor control system>

0040<figref idref="f0003">FIG. 3</figref> shows a function block diagram of the motor control system. The motor control system is used for controlling the hub 10 within which the motor is incorporated for assisting the rotation of the bicycle wheel.

0041The hub 10 within which the motor is incorporated comprises the control part 71 for the motor and the communication part 72 for the motor.

0042The control part 71 for the motor judges the state of communication in the communication part 72 for the motor, e.g., the state of communication between the communication part 72 for the motor and the overall communication part 78. The control part 71 for the motor also judges the state of rotation of the wheel based on information from a rotation detecting part 74. The control part 71 for the motor is configured so as to include the CPU, the ROM, and the RAM. The basic function of these devices is the same as that described for the overall control part 12 described above.

0043The control part 71 for the motor has the rotation detecting part 74, a first mode switching part 75, a second mode switching part 76, a stoppage time calculating part 73, and a charge monitoring part 77.

0044The rotation detecting part 74 detects the state of rotation of the wheel. The rotation detecting part 74 detects the state of rotation of the wheel using, e.g., a rotation sensor (not shown) for detecting the number of rotations of the front wheel of the bicycle. The rotation sensor is incorporated in the hub 10 within which the motor is incorporated. The rotation sensor generates a pulse-shaped voltage every time the front wheel makes a single rotation. The rotation detecting part 74 continually writes the time at which the pulse-shaped voltage is detected onto the RAM. From the time of a pulse detected during a given cycle and the time of a pulse detected during the next cycle, the rotation detecting part 74 calculates the time taken for the front wheel to rotate once and calculates the number of rotations of the front wheel for every minute (i.e., rpm). Also, using the information above, the rotation detecting part 74 can calculate the speed of rotation of the front wheel for every minute. Although a rotation sensor is used here, the rotation detecting part 74 may detect at least one of the number of rotations and the speed of rotation based on the frequency of the current flowing to the main motor body 10a.

0045The first mode switching part 75 switches the operation mode of the main motor body 10a from the driving mode to the power generating mode based on a first mode switching signal from the overall control part 12. The first mode switching signal is supplied from the overall control part 12 to the first mode switching part 75 according to at least one state among the state of communication between the hub 10 within which the motor is incorporated and the overall control part 12, the state of rotation of the wheel, and the charge state in the power-storing part 14.

0046The first mode switching part 75 switches the operation mode of the main motor body 10a from the driving mode (i.e., assist mode), in which the motor is capable of assisting rotation of the bicycle wheel, to a power generating mode (i.e., dynamo mode), in which the motor outputs electrical power that has been generated using rotation of the bicycle wheel, according to the state of communication with the overall control part 12. In detail, the first mode switching part 75 switches the operation mode of the main motor body 10a according to the state of communication with the overall control part 12 and the state of rotation of the wheel. Specifically, the first mode switching part 75 switches the mode of the main motor body 10a from the driving mode to the power generating mode in a circumstance in which the speed of rotation of the wheel is greater than a predetermined speed of rotation and communication with the overall control part 12 is disabled for a predetermined time or longer.

0047The second mode switching part 76 switches the operation mode of the main motor body 10a from the power generating mode to the driving mode based on a second mode switching signal from the overall control part 12. The second mode switching signal is supplied from the overall control part 12 to the second mode switching part 76 according to the state of communication between the hub 10 within which the motor is incorporated and the overall control part 12, the state of rotation of the wheel, and the charge state in the power-storing part 14.

0048The state of communication between the hub 10 within which the motor is incorporated and the overall control part 12 is judged according to whether or not the time of communication is equal to or greater than a predetermined time. For example, in a circumstance in which the time of communication is equal to or greater than the predetermined time, the operation mode of the main motor body 10a is switched. The state of rotation of the wheel is detected by the rotation detecting part 74. Here, a description is given for an example of a circumstance in which the mode of the hub 10 within which the motor is incorporated is switched based on the number of rotations of the wheel. However, the mode of the hub 10 within which the motor is incorporated may be switched based on the distance over which the bicycle travels. In such a circumstance, the travel distance may be calculated in, e.g., the control part 71 for the motor using the result of detection by the rotation detecting part 74 and dimensions of the wheel of the bicycle which have been registered in advance. The charge state in the power-storing part 14 is managed by the charge monitoring part 77.

0049The charge monitoring part 77 manages the charge state of the power-storing part 14. The charge monitoring part 77 judges whether or not the amount of charge in the power-storing part 14 is equal to or greater than a predetermined value. For example, the operation mode of the main motor body 10a is switched in a circumstance in which the first mode switching signal is received in a circumstance in which the amount of charge in the power-storing part 14 is equal to or greater than the predetermined value. The stoppage time calculating part 73 calculates the time for which communication with the electrical components 20 is stopped. Although the charge monitoring part 77 is provided in this circumstance, the charge monitoring part 77 does not have to be provided, and may merely be provided as necessary.

0050The communication part 72 for the motor performs power line communication with the overall communication part 78. The communication part 72 for the motor can be actuated by electrical power generated by the hub 10 within which the motor is incorporated. Supply of electrical power and transmission of signals are performed simultaneously using the power line 70 using, e.g., PLC, as described above.

0051The overall control part 12 controls, e.g., the electrical components 20, the hub 10 within which the motor is incorporated, and the power-storing part 14. The overall control part 12 issues the first mode switching signal described above and issues the second mode switching signal described above. The overall control part 12 is activated by electrical power from the hub 10, within which the motor is incorporated, in the power generating mode and is actuated by electrical power from the power-storing part 14 in the driving mode. The overall control part 12 comprises the overall communication part 78. The overall communication part 78 performs communication with the communication part 72 for the motor and other overall communication parts 78.

0052Each of the other electrical components 20 has a communication part (not shown). The communication part of each of the electrical components 20 performs communication with the overall communication part 78. The communication part of each of the electrical components 20 performs communication between the electrical components 20. Communication in this case is power line communication. Supply of electrical power and transmission of signals are performed simultaneously using the power line 70 using, e.g., PLC, as described above.

<Operation of the motor control system>

<First embodiment>

0053<figref idref="f0004">FIG. 4</figref> shows a flow of the motor control system described above. The motor control system is a system for controlling the hub 10 within which the motor is incorporated. The motor control system has a function of switching the operation mode of the main motor body 10a from the driving mode to the power generating mode and a function of switching the operation mode of the main motor body 10a from the power generating mode to the driving mode.

0054An example of operation of the motor control system will now be described.

0055When electrical power is supplied from the control part 71 for the motor, the main flow is initiated. First, the control part 71 for the motor judges whether or not communication is being performed from the overall control part 12 to the hub 10 within which the motor is incorporated (S1). For example, the control part 71 for the motor judges whether or not transmission/reception of a signal is being performed between the communication part 72 for the motor and the overall communication part 78. In a circumstance in which transmission/reception of a signal has stopped between the communication part 72 for the motor and the overall communication part 78 (i.e., "No" in S1), the control part 71 for the motor judges whether or not the time for which the signal is stopped is equal to or greater than a predetermined time (S2).

0056Next, in a circumstance in which the time for which the signal is stopped is equal to or greater than the predetermined time (i.e., "Yes" in S2), the control part 71 for the motor judges whether or not the speed of rotation of the wheel, e.g., the speed of rotation of the front wheel, is greater than a predetermined speed of rotation (S3). In a circumstance in which the speed of rotation of the front wheel is greater than the predetermined speed of rotation (i.e., "Yes" in S3), the control part 71 for the motor switches the operation mode of the main motor body 10a from the driving mode to the power generating mode (S4).

0057Next, the control part 71 for the motor judges whether or not to switch the operation mode of the main motor body 10a from the power generating mode to the driving mode (S6). For example, in a circumstance in which the second mode switching signal is issued by the overall control part 12 and the second mode switching signal is received by the communication part 72 for the motor, the control part 71 for the motor switches the operation mode of the main motor body 10a from the power generating mode to the driving mode, based on the second mode switching signal (i.e., "Yes" in S6). In a state in which the second mode switching signal is not being inputted into the communication part 72 for the motor, the control part 71 for the motor monitors the input of the second mode switching signal (i.e., "No" in S6).

0058Meanwhile, in a circumstance in which transmission/reception of a signal is being performed between the communication part 72 for the motor and the overall communication part 78 (i.e., "Yes" in S1), the control part 71 for the motor operates the main motor body 10a in the driving mode (S7). Next, the control part 71 for the motor judges whether or not to switch the operation mode of the main motor body 10a from the driving mode to the power generating mode (S8). For example, in a circumstance in which the first mode switching signal is issued by the overall control part 12 and the first mode switching signal is received by the communication part 72 for the motor, the control part 71 for the motor switches the operation mode of the main motor body 10a from the driving mode to the power generating mode, based on the first mode switching signal (i.e., "Yes" in S8). In a state in which the hub 10 within which the motor is incorporated is operating in the driving mode, (i.e., S7, and "No" in S8), the control in step 1 (S1) is performed.

0059Although the end is not displayed in the above flow, the above flow ends when supply of electrical power to the control part 71 for the motor is stopped. For example, when electrical power is not supplied from the power line 70 to the control part 71 for the motor and rotation of the wheel stops, the above flow ends.

0060As described above, in the present embodiment, the control part 71 for the motor dynamically switches the operation mode of the main motor body 10a from the driving mode to the power generating mode according to the state of communication between the hub 10 within which the motor is incorporated and the electrical components 20 and the state of rotation of the wheel, thereby making it possible to set the operation mode of the main motor body 10a to the appropriate mode.

0061According to the present embodiment, moreover, the control part 71 for the motor can dynamically switch the operation mode of the main motor body 10a from the power generating mode to the driving mode in a circumstance in which power generating mode has been enabled as the operation mode, and dynamically switch the operation mode of the main motor body 10a from the driving mode to the power generating mode in a circumstance in which driving mode has been enabled as the operation mode. It is thereby possible to set the operation mode of the main motor body 10a to the appropriate mode.

<Second embodiment>

0062<figref idref="f0005">FIG. 5</figref> shows a flow of the motor control system according to a second embodiment. The motor control system according to the second embodiment is a system for controlling the hub 10 within which the motor is incorporated. The basic configuration is similar to that of the motor control system according to the first embodiment; only the control flow differs. The flow of the motor control system shown in <figref idref="f0005">FIG. 5</figref> (S11 through S 18) is the same as the flow of the motor control system shown in <figref idref="f0004">FIG. 4</figref> with the exception of the section for step 15 (S 15) described further below. In other words, each of the steps 11 through 14 and 16 through 18 shown in <figref idref="f0005">FIG. 5</figref> corresponds with each of the steps 1 through 4 and 6 through 8 shown in <figref idref="f0004">FIG. 4</figref>. Therefore, a description of sections in which the processing procedure is identical to that in the flow of the motor control system according to the first embodiment shown in <figref idref="f0004">FIG. 4</figref> shall not be provided.

0063In the motor control system according to the second embodiment, when the control part 71 for the motor switches the operation mode of the main motor body 10a to the power generating mode at step S 14 (S 14), the control part 71 for the motor monitors whether or not the amount of charge in the power-storing part 14 is equal to or greater than the predetermined value (S 15). In a circumstance in which the amount of charge in the power-storing part 14 is equal to or greater than the predetermined value ("Yes" in S 15), the control in step 16 (S 16) is performed.

0064As described above, in the present embodiment, the operation mode of the main motor body 10a is dynamically switched in the hub 10 within which the motor is incorporated from the power generating mode to the driving mode according to the charge state in the power-storing part 14, thereby making it possible to set the operation mode of the main motor body 10a in an appropriate manner. Also, sections of the control that are identical to those in the previous embodiment make it possible for a similar effect to be obtained.

<Third embodiment>

0065<figref idref="f0006">FIG. 6</figref> shows a flow of the motor control system according to a third embodiment. The motor control system according to the third embodiment is a system for controlling the hub 10 within which the motor is incorporated. The basic configuration is similar to that of the motor control system according to the first embodiment; only the control flow differs. The flow of the motor control system according to the third embodiment shown in <figref idref="f0006">FIG. 6</figref> (S21 through S28) is the same as the flow of the motor control system according to the first embodiment shown in <figref idref="f0004">FIG. 4</figref> with the exception of sections for step 2 (S2) and step 3 (S3) of the flow of the motor control system according to the first embodiment shown in <figref idref="f0004">FIG. 4</figref>. In other words, each of the steps 21, 24 and 26 through 28 shown in <figref idref="f0006">FIG. 6</figref> corresponds with each of the steps 1, 4 and 6 through 8 shown in <figref idref="f0004">FIG. 4</figref>. Therefore, a description of sections in which the processing procedure is identical to that in the flow of the motor control system according to the first embodiment shown in <figref idref="f0004">FIG. 4</figref> shall not be provided.

0066In the flow of the motor control system according to the third embodiment shown in <figref idref="f0006">FIG. 6</figref>, in a circumstance in which it is judged in step 21 (S21) that transmission/reception of signals is not being performed between the communication part 72 for the motor and the overall communication part 78, e.g., in a circumstance in which transmission/reception of signals has stopped between the communication part 72 for the motor and the overall communication part 78 (i.e., "No" in S21), the control part 71 for the motor switches the operation mode of the main motor body 10a from the driving mode to the power generating mode (S24).

0067As described above, in the present embodiment, the control part 71 for the motor dynamically switches the operation mode of the main motor body 10a from the driving mode to the power generating mode according to the state of communication between the hub 10 within which the motor is incorporated and the electrical component 20, thereby making it possible to set the operation mode of the main motor body 10a in an appropriate manner. Also, sections of the control that are identical to those in the previous embodiment make it possible for a similar effect to be obtained.

<Fourth embodiment>

0068<figref idref="f0007">FIG. 7</figref> shows a flow of the motor control system according to a fourth embodiment. The motor control system according to the fourth embodiment is a system for controlling the hub 10 within which the motor is incorporated. The basic configuration is similar to that of the motor control system according to the first embodiment; only the control flow differs. The flow of the motor control system shown in <figref idref="f0007">FIG. 7</figref> (S31 through S38) is the same as the flow of the motor control system according to the first embodiment shown in <figref idref="f0004">FIG. 4</figref> with the exception of the section for step 3 (S3) of the flow of the motor control system according to the first embodiment shown in <figref idref="f0004">FIG. 4</figref>. In other words, each of the steps 31, 32, 34, and 36 through 28 shown in <figref idref="f0007">FIG. 7</figref> corresponds with each of the steps 1, 2, 4, and 6 through 8 shown in <figref idref="f0004">FIG. 4</figref>. Therefore, a description of sections in which the processing procedure is identical to that in the flow of the motor control system according to the first embodiment shown in <figref idref="f0004">FIG. 4</figref> shall not be provided.

0069In the flow of the motor control system according to the fourth embodiment shown in <figref idref="f0007">FIG. 7</figref>, the control part 71 for the motor judges, in step 32 (S32), whether or not the time for which signal transmission/reception between the communication part 72 for the motor and the overall communication part 78 has stopped (i.e., stoppage time) is equal to or greater than a predetermined time (S32). In a circumstance in which the signal stoppage time is equal to or greater than the predetermined time (i.e., "Yes" in S32), the control part 71 for the motor switches the operation mode of the main motor body 10a from the driving mode to the power generating mode based on this first mode switching signal (S34).

0070As described above, in the present embodiment, the control part 71 for the motor dynamically switches the operation mode of the main motor body 10a from the driving mode to the power generating mode according to the time for which communication between the hub 10 within which the motor is incorporated and the electrical component 20 has stopped, thereby making it possible to set the operation mode of the main motor body 10a in an appropriate manner. Also, sections of the control that are identical to those in the previous embodiment make it possible for a similar effect to be obtained.

<Fifth embodiment>

0071<figref idref="f0008">FIG. 8</figref> shows a flow of the motor control system according to a fifth embodiment. The motor control system according to the fifth embodiment is a system for controlling the hub 10 within which the motor is incorporated. The basic configuration is similar to that of the motor control system according to the first embodiment; only the control flow differs. The flow of the motor control system according to the fifth embodiment shown in <figref idref="f0008">FIG. 8</figref> (S41 through S48) is the same as the flow of the motor control system according to the first embodiment shown in <figref idref="f0004">FIG. 4</figref> with the exception of the section for step 2 (S2) of the flow of the motor control system according to the first embodiment shown in <figref idref="f0004">FIG. 4</figref>. In other words, each of the steps 41, 43, 44, and 46 through 48 shown in <figref idref="f0008">FIG. 8</figref> corresponds with each of the steps 1, 3, 4, and 6 through 8 shown in <figref idref="f0004">FIG. 4</figref>. Therefore, a description of sections in which the processing procedure is identical to that in the flow of the motor control system shown in <figref idref="f0004">FIG. 4</figref> shall not be provided.

0072In the motor control system according to the fifth embodiment shown in <figref idref="f0008">FIG. 8</figref>, the control part 71 for the motor judges, in step 43 (S43), whether or not the speed of rotation of the wheel, e.g., the speed of rotation of the front wheel, is greater than a predetermined speed of rotation. In a circumstance in which the speed of rotation of the front wheel is greater than the predetermined speed of rotation (i.e., "Yes" in S43), the control part 71 for the motor switches the operation mode of the main motor body 10a from the driving mode to the power generating mode (S44).

0073As described above, in the present embodiment, the control part 71 for the motor dynamically switches the operation mode of the main motor body 10a from the driving mode to the power generating mode according to the speed of rotation of the wheel, thereby making it possible to set the operation mode of the main motor body 10a in an appropriate manner. Also, sections of the control that are identical to those in the previous embodiment make it possible for a similar effect to be obtained.

<Sixth embodiment>

0074<figref idref="f0009">FIG. 9</figref> shows a flow of the motor control system according to a sixth embodiment. The motor control system according to the sixth embodiment is a system for controlling the hub 10 within which the motor is incorporated. The basic configuration is similar to that of the motor control system according to the first embodiment; only the control flow differs. The flow of the motor control system shown in <figref idref="f0009">FIG. 9</figref> (S51 through S58) is the same as the flow of the motor control system according to the first embodiment shown in <figref idref="f0004">FIG. 4</figref> with the exception of the section for step 55. In other words, each of the steps 51 through 54 and 56 through 58 shown in <figref idref="f0009">FIG. 9</figref> corresponds with each of the steps 1 through 4 and 6 through 8 shown in <figref idref="f0004">FIG. 4</figref>. Therefore, a description of sections in which the processing procedure is identical to that in the flow of the motor control system according to the first embodiment shown in <figref idref="f0004">FIG. 4</figref> shall not be provided.

0075In the flow of the motor control system according to the sixth embodiment shown in <figref idref="f0009">FIG. 9</figref>, when the operation mode of the main motor body 10a is switched to the power generating mode in step 54 (S54), the control part 71 for the motor calculates the time of communication with the overall communication part 78, and the control part 71 for the motor judges whether or not the time of communication is equal to or greater than a predetermined time (S55). In a circumstance in which the time of communication has become equal to or greater than the predetermined time (i.e., "Yes" in S55), the control in step 56 (S56) is performed. Meanwhile, in a circumstance in which the time of communication is less than the predetermined time (i.e., "No" in S55), the time of communication is monitored by the control part 71 for the motor until the time of communication becomes equal to or greater than the predetermined time (i.e., "No" in S55).

0076As described above, in the present embodiment, the control part 71 for the motor dynamically switches the operation mode of the main motor body 10a from the driving mode to the power generating mode according to the state of communication between the hub 10 within which the motor is incorporated and the overall control part 12 and the state of rotation of the wheel, thereby making it possible to set the operation mode of the main motor body 10a in an appropriate manner.

0077Also, in the present embodiment, it is possible to dynamically switch the operation mode of the main motor body 10a from the power generating mode to the driving mode according to the state of communication between the hub 10 within which the motor is incorporated and the overall control part 12, thereby making it possible to set the operation mode of the main motor body 10a in an appropriate manner. Also, sections of the control that are identical to those in the previous embodiment make it possible for a similar effect to be obtained.

<Seventh embodiment>

0078<figref idref="f0010">FIG. 10</figref> shows a flow of the motor control system according to a seventh embodiment. The motor control system according to the seventh embodiment is a system for controlling the hub 10 within which the motor is incorporated. The basic configuration is similar to that of the motor control system according to the first embodiment; only the control flow differs. The flow of the motor control system according to the seventh embodiment shown in <figref idref="f0010">FIG. 10</figref> (S61 through S68) is the same as the flow of the motor control system according to the first embodiment shown in <figref idref="f0004">FIG. 4</figref> with the exception of the section for step 65 (S65). In other words, each of the steps 11 through 14 and 16 through 18 shown in <figref idref="f0005">FIG. 5</figref> corresponds with each of the steps 1 through 4 and 6 through 8 shown in <figref idref="f0004">FIG. 4</figref>. Therefore, a description of sections in which the processing procedure is identical to that in the flow of the motor control system according to the first embodiment shown in <figref idref="f0004">FIG. 4</figref> shall not be provided.

0079In the flow of the motor control system according to the seventh embodiment shown in <figref idref="f0010">FIG. 10</figref>, when the operation mode of the main motor body 10a is switched to the power generating mode in step 64 (S64), the control part 71 for the motor judges whether or not the number of rotations of the wheel, e.g., the number of rotations of the front wheel, has become equal to or greater than a predetermined number (S65). In a circumstance in which the number of rotations of the front wheel becomes equal to or greater than the predetermined number of rotations (i.e., "Yes" in S65), the control in step 66 (S66) is performed. Meanwhile, in a circumstance in which the number of rotations of the front wheel is less than the predetermined number of rotations (i.e., "No" in S65), the number of rotations is monitored by the control part 71 for the motor until the number of rotations becomes equal to or greater than the predetermined number of rotations.

0080As described above, in the present embodiment, the operation mode of the main motor body 10a is dynamically switched from the driving mode to the power generating mode according to the state of communication between the hub 10 within which the motor is incorporated and the electrical components 20 and the state of rotation of the wheel, thereby making it possible to set the operation mode of the main motor body 10a in an appropriate manner.

0081Also, in the present embodiment, the control part 71 for the motor dynamically switches the operation mode of the main motor body 10a from the driving mode to the power generating mode according to the state of rotation of the wheel, thereby making it possible to set the operation mode of the main motor body 10a in an appropriate manner. Also, sections of the control that are identical to those in the previous embodiment make it possible for a similar effect to be obtained.

<Other embodiments>

0082Although an embodiment of the present invention has been described above, the present invention is not limited in scope thereby; a variety of modifications being possible without departing from the scope of the invention. <ul id="ul0002" list-style="none" compact="compact"><li>(a) Although in the above embodiments, the forward-illuminating light 23 and other electrical components are shown as examples of the other electrical components 20, the electrical components 20 are not limited to those shown above. The electrical components 20 include all electrical components 20 that can be installed on a bicycle.</li><li>(b) Another embodiment may be configured in a similar manner to the second embodiment, wherein step 16 is omitted, and in a circumstance in which the decision at step 15 is "Yes", the flow proceeds to step 17.</li><li>(c) Another embodiment may be configured in a similar manner to the sixth embodiment, wherein step 56 is omitted, and in a circumstance in which the decision at step 15 is "Yes", the flow proceeds to step 57.</li><li>(d) Another embodiment may be configured in a similar manner to the seventh embodiment, wherein step 66 is omitted, and in a circumstance in which the decision at step 15 is "Yes", the flow proceeds to step 67.</li><li>(e) Although in the above embodiments, the power-assisted bicycle is configured so as to have an external shifting device, the power-assisted bicycle may also be configured so as to have an internal shifting device, or to have no shifting device. The present system can be applied to all types of power-assisted bicycles.</li><li>(g) Although in the present embodiment, the motor-incorporating hub is provided to the front of the power-assisted bicycle, the present system can be applied to a configuration in which the motor-incorporating hub is provided to the rear, or to a configuration in which a motor is provided to the vicinity of a pedal crank to apply a driving force to the chain or to drive the pedal crank.</li></ul>

[Key]

0083<dl id="dl0001" compact="compact"><dt>10</dt><dd>Motor-incorporating hub</dd><dt>10a</dt><dd>Main motor body (motor)</dd><dt>12</dt><dd>Overall control part</dd><dt>14</dt><dd>Power-storing part</dd><dt>19</dt><dd>Electrical circuit part</dd><dt>20</dt><dd>Other electrical component</dd><dt>71</dt><dd>Control part for motor</dd><dt>72</dt><dd>Communication part for motor</dd><dt>73</dt><dd>Stoppage time calculating part</dd><dt>74</dt><dd>Rotation detecting part</dd><dt>75</dt><dd>First mode switching part</dd><dt>76</dt><dd>Second mode switching part</dd><dt>77</dt><dd>Charge monitoring part</dd><dt>78</dt><dd>Overall communication part (communication part for communicating with electrical component)</dd></dl>