Electrically assisted bicycle, its drive system, and control method for electrically assisted bicycle

Abstract

To allow for control at an assist ratio higher than that in a control mode that can be selected by an up-button or a down-button.SOLUTION: A mode selection unit 32 selects a first control mode in accordance with a mode selection operation from a plurality of first control modes that can be selected by a mode selection operation to a user interface device. A motor control unit 31 includes the plurality of first control modes and a control cancel mode, as control modes of an electric motor. Upper limit ratios being upper limits of the assist ratio realized by driving of the electric motor are defined for the plurality of first control modes and the control cancel mode. The upper limit assist ratio of an intensive mode is defined to decrease in accordance with an increase of a vehicle speed in a vehicle speed range higher than a first vehicle speed V1. The upper limit assist ratio is defined for the control cancel mode to be higher than that for the intensive mode in the vehicle speed range higher than the first vehicle speed V1 in comparison at the same vehicle speed.SELECTED DRAWING: Figure 4

Description

[Technical Field]

[0001] The present invention relates to an electrically assisted bicycle, a drive system thereof, and a control method for an electrically assisted bicycle. [Background technology]

[0002] Electrically assisted bicycles use a map that associates vehicle speed with an assist ratio. The assist ratio is the ratio between the torque generated by pedaling (hereinafter referred to as pedal torque) and the torque generated by the electric motor (hereinafter referred to as motor torque). In the control of an electrically assisted bicycle exemplified in Patent Document 1, the assist ratio is constant up to 15 km, and gradually decreases in accordance with vehicle speed from 15 km to 24 km (i.e., motor torque decreases in accordance with an increase in vehicle speed). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2001-080569 Summary of the Invention [Problem to be solved by the invention]

[0004] Patent Document 1 discloses multiple modes, including Mode A and Mode B. Switching between these two modes can be achieved by operating a switch (one button operation). In either mode, the assist ratio gradually decreases depending on the vehicle speed from 15 km to 24 km. Furthermore, in either mode, when the vehicle speed reaches 24 km, the assist ratio becomes 0 and the assist by the electric motor stops. Such restrictions on the assist by the electric motor are not necessarily convenient for the user. [Means for solving the problem]

[0005] The drive system for an electrically assisted bicycle proposed in this disclosure includes a user interface device having at least one input unit that accepts a mode selection operation by the rider, a mode selection unit that selects a first control mode corresponding to the mode selection operation from a plurality of first control modes selectable by the mode selection operation, and a motor control unit that controls the electric motor in the selected first control mode based on the vehicle speed detected by a sensor. The motor control unit includes the plurality of first control modes and a second control mode as control modes for the electric motor, and each of the plurality of first control modes and the second control mode is defined with an upper limit assist ratio that is the upper limit of the assist ratio achieved by driving the electric motor. One of the plurality of first control modes is defined with the highest upper limit assist ratio among the plurality of first control modes, and the upper limit assist ratio of the one of the plurality of first control modes is defined to decrease as the vehicle speed increases in a vehicle speed range higher than a first vehicle speed. The second control mode is defined with an upper limit assist ratio that is higher than that of one of the plurality of first control modes when compared at the same vehicle speed in a vehicle speed range higher than the first vehicle speed. With this drive system, by using the second control mode, it is possible to achieve an assist ratio higher than that of the plurality of first control modes selectable by a mode selection operation.

[0006] (1) In the first example of the drive system, the mode selection unit allows selection of the second control mode on the condition that authentication of the driver is successful. According to this drive system, use of the second control mode can be permitted only for drivers who have been successfully authenticated.

[0007] (2) In a second example of the drive system, the mode selection unit allows selection of the second control mode when the user's pedaling ability satisfies a predetermined condition. According to this drive system, use of the second control mode can be permitted only for drivers whose pedaling ability satisfies the predetermined condition.

[0008] (3) In a third example of the drive system, the mode selection unit allows selection of the second control mode when the driving environment satisfies a predetermined condition. With this drive system, the second control mode can be allowed to be used only in a driving environment that satisfies the predetermined condition.

[0009] (4) In the drive system of (1) to (3), first assist ratio defining information that associates vehicle speed with an assist ratio may be used in the one of the plurality of first control modes, and second assist ratio defining information that associates vehicle speed with an assist ratio may be used in the second control mode. The first assist ratio defining information may define a first assist ratio as the upper limit assist ratio for a vehicle speed range lower than the first vehicle speed, and may define the upper limit assist ratio that decreases as the vehicle speed increases for a vehicle speed range higher than the first vehicle speed. The second assist ratio defining information may define an upper limit assist ratio for a vehicle speed range higher than the first vehicle speed that is higher than the upper limit assist ratio defined by the first assist ratio defining information when compared at the same vehicle speed.

[0010] (5) In the drive system of (1) to (3), the upper limit assist ratio specified in one of the plurality of first control modes may be the first assist ratio in a vehicle speed range lower than the first vehicle speed, and the upper limit assist ratio specified in the second control mode may be the first assist ratio in at least a portion of a vehicle speed range higher than the first vehicle speed.

[0011] (6) In the drive system of (1) to (3), the upper limit assist ratio defined for the second control mode may decrease as the vehicle speed increases in a vehicle speed range higher than a second vehicle speed that is higher than the first vehicle speed.

[0012] (7) In the drive system of (1), the user interface device may have a plurality of input units, including the at least one input unit, that accept driver operations. When a predetermined authentication operation is performed on the plurality of input units, the mode selection unit may determine that authentication has been successful and allow selection of the second control mode. This allows authentication to be performed without using a dedicated device or component.

[0013] (8) The drive system of (7) may further include an authentication operation setting unit that sets the predetermined authentication operation based on the driver's operation of the plurality of input units. This allows the user to change the authentication operation as needed.

[0014] (9) In the drive system of (7), the at least one input unit includes a button for the driver to switch between the plurality of first control modes, which can prevent an increase in the number of parts of the user interface device.

[0015] (10) In the drive system of (1), the mode selection unit may stop the selection of the second control mode when a predetermined selection stop operation is performed on the input units while the second control mode is selected. This allows the driver to easily return to one of the first control modes.

[0016] (11) The drive system of (1) may further include a connection unit for connecting an authentication device or an authentication component. When the authentication device or the authentication component is connected to the connection unit, the mode selection unit may determine that authentication has been successful and allow selection of the second control mode. Here, the authentication device may be, for example, a mobile terminal carried by the bicycle owner, and the authentication component may be, for example, a mechanical key or an electronic key.

[0017] (12) In the drive system of (2), the mode selection unit may determine whether to allow selection of the second control mode by using at least one of the force acting on the pedal, the rotation speed of the pedal, the balance between the left and right sides, and the reaction speed to the load as the user's pedaling ability.

[0018] (13) In the drive system of (2), the upper limit assist ratio defined for the second control mode may decrease as the vehicle speed increases in a vehicle speed range higher than a second vehicle speed that is higher than the first vehicle speed, and the second vehicle speed may change in accordance with the pedaling ability of the driver. This allows a driver with high pedaling ability to enjoy a more comfortable ride.

[0019] (14) In the drive system of (3), the riding environment may be at least one of the road slope, road surface condition, load acting on the bicycle, brightness around the bicycle, weather, and traffic congestion.

[0020] (15) The electric assist bicycle proposed in this disclosure has a drive system of (1), (2), or (3).

[0021] The present disclosure proposes a control method for an electrically assisted bicycle having a user interface device with at least one input unit that accepts a mode selection operation by a rider. The control method includes a mode selection step of selecting a first control mode corresponding to the mode selection operation from a plurality of first control modes selectable by the mode selection operation, each having a different assist ratio, and a motor control step of controlling the electric motor in the selected first control mode based on the vehicle speed detected by a sensor. The motor control step includes the plurality of first control modes and a second control mode as control modes for the electric motor. Each of the plurality of first control modes and the second control mode is defined with an upper limit assist ratio that is the upper limit of the assist ratio achieved by driving the electric motor. One of the plurality of first control modes is defined with the highest upper limit assist ratio among the plurality of first control modes, and the upper limit assist ratio of the one of the plurality of first control modes is defined to decrease as the vehicle speed increases in a vehicle speed range higher than a first vehicle speed. The second control mode is defined with an upper limit assist ratio that is higher than that of one of the plurality of first control modes when compared at the same vehicle speed in a vehicle speed range higher than the first vehicle speed. According to this control method, by using the second control mode, an assist ratio higher than that of the plurality of first control modes selectable by a mode selection operation can be achieved.

[0022] (16) In the first example of the control method, the mode selection step determines whether to allow selection of the second control mode on the condition that authentication of the driver is successful. According to this control method, use of the second control mode can be allowed only for drivers who have been successfully authenticated.

[0023] (17) In a second example of the control method, the mode selection step allows selection of the second control mode when the user's pedaling ability satisfies a predetermined condition. According to this control method, use of the second control mode can be allowed only for drivers whose pedaling ability satisfies the predetermined condition.

[0024] (18) In a third example of the control method, the mode selection step allows selection of the second control mode when the driving environment satisfies a predetermined condition. According to this control method, use of the second control mode can be allowed only in a driving environment that satisfies the predetermined condition. [Brief explanation of the drawings]

[0025] [Figure 1] 1 is a side view showing an example of a vehicle proposed in the present disclosure. [Figure 2] 1 is a block diagram showing the configuration of an electrically assisted bicycle according to a first example. [Figure 3] FIG. 1 illustrates an example of a user interface device. [Figure 4] FIG. 2 is a block diagram showing functions of a control device. [Figure 5] FIG. 10 is a diagram showing an example of an upper limit assist ratio defined in the assist ratio defining information referenced in a strong mode, a medium mode, and a weak mode (plurality of first control modes). [Figure 6A] FIG. 10 is a diagram showing an example of an upper limit assist ratio defined in the assist ratio defining information referenced in the restriction release mode (second control mode). [Figure 6B] FIG. 10 is a diagram showing another example of the upper limit assist ratio defined in the assist ratio defining information referenced in the restriction release mode. [Figure 6C] FIG. 10 is a diagram showing yet another example of the upper limit assist ratio defined in the assist ratio defining information referenced in the restriction release mode. [Figure 6D] FIG. 10 is a diagram showing yet another example of the upper limit assist ratio defined in the assist ratio defining information referenced in the restriction release mode. [Figure 7] FIG. 10 is a flowchart illustrating an example of processing executed by a mode selection unit. [Figure 8] 10 is a diagram showing yet another example of the upper limit assist ratio defined by the assist ratio defining information referenced in the restriction release mode. This diagram shows upper limit assist ratios defined by three pieces of assist ratio defining information that can be referenced in the restriction release mode. [Figure 9] 9 is a flowchart showing an example of a process for utilizing the assist ratio defining information exemplified in FIG. 8. FIG. [Figure 10] FIG. 10 is a block diagram showing the configuration of an electrically assisted bicycle according to a second example. [Figure 11] 11 is a block diagram showing functions of a control device in the electrically assisted bicycle shown in FIG. 10. FIG. [Figure 12] FIG. 10 is a diagram showing a map for calculating pedaling ability from cadence and pedaling force. [Figure 13] 10 is a diagram showing an example of an upper limit assist ratio defined in assist ratio defining information referenced in a control device according to a second example. FIG. [Figure 14] FIG. 10 is a block diagram showing the configuration of an electrically assisted bicycle according to a third example. [Figure 15] 15 is a block diagram showing functions of a control device in the electrically assisted bicycle shown in FIG. 14. FIG. DETAILED DESCRIPTION OF THE INVENTION

[0026] An embodiment of the present invention will be described below. Fig. 1 is a side view of an electrically assisted bicycle 100, which is an example of an embodiment of the present invention. Fig. 2 is a block diagram showing the configuration of the electrically assisted bicycle 100. In Fig. 2, thick solid lines represent the transmission of power, and thin solid lines represent electrical signals and currents. Hereinafter, the electrically assisted bicycle 100 will be simply referred to as a bicycle.

[0027] The bicycle 100 has a drive system for assisting the rider in pedaling. The drive system is made up of electrical components such as an electric motor 14, a control device 30, a motor drive device 13, and a UI device 50, which will be described later.

[0028] [Overall configuration] As shown in FIG. 1, bicycle 100 has a crankshaft 7. Pedals 6 are attached to the right and left ends of crankshaft 7 via crank arms. The crankshaft 7 is located below the lower end of seat tube 1b. A saddle 2 is attached to the upper end of seat tube 1b. At the front of bicycle 100 are provided a handlebar stem 8, handlebars 9 connected to the upper part of handlebar stem 8, a front fork 8a connected to the lower part of handlebar stem 8, and a front wheel 3 supported by the lower end of the front fork 8a. The handlebar stem 8 is supported by a head pipe 1a attached to the front end of frame 1. The shape of frame 1 is not limited to the example shown in FIG. 1 and may be modified as appropriate.

[0029] As shown in FIG. 1, bicycle 100 has a drive unit 20. Drive unit 20 has an electric motor 14 (see FIG. 2) that outputs an assist force (assist torque) that assists the rider in driving rear wheel 4 (pedaling 6), and a reducer 21 (see FIG. 2). Electric motor 14 is driven by power supplied from battery 15 (see FIG. 1). Battery 15 is attached, for example, to the rear side of seat tube 1b. Drive unit 20 is disposed behind crankshaft 7. The positions of electric motor 14 and battery 15 are not limited to those in the example of bicycle 100 and may be changed as appropriate.

[0030] As shown in FIG. 2, the force applied to the crankshaft 7 through the pedals 6 is transmitted to the resultant force transmission mechanism 22. Furthermore, the power (assist force) output from the electric motor 14 is transmitted to the resultant force transmission mechanism 22 through a reducer 21. The resultant force transmission mechanism 22 is composed of a shaft, rotating members (gears, sprockets, etc.) attached to the shaft, and power transmission members (for example, a chain 5, a shaft, a belt, etc.). Both the force applied to the crankshaft 7 and the power output from the electric motor 14 are input to the resultant force transmission mechanism 22. The power combined by the resultant force transmission mechanism 22 is transmitted to the rear wheel 4. The power combined by the resultant force transmission mechanism 22 may be input to the rear wheel 4 via a transmission mechanism whose gear ratio can be changed by operation of the rider.

[0031] As shown in FIG. 2, the drive system of bicycle 100 has a pedal force sensor 41 for detecting the pedal force applied by the rider to pedal 6. Pedal force sensor 41 is a torque sensor that outputs a signal corresponding to the torque generated in crankshaft 7. Pedal force sensor 41 is, for example, a magnetostrictive sensor provided on crankshaft 7, but other types of sensors may also be used. Hereinafter, the torque of crankshaft 7 will be referred to as "pedal force."

[0032] 2, the drive system of the bicycle 100 has a vehicle speed sensor 42 that outputs a signal corresponding to the vehicle speed. The vehicle speed sensor 42 is provided, for example, on the front wheel 3 and outputs a signal corresponding to the rotation of the front wheel 3. The vehicle speed sensor 42 may also be provided on the rear wheel 4.

[0033] [Control device] As shown in Figure 2, the drive system of the bicycle 100 has a control device 30 that controls the electric motor 14. The control device 30 includes a memory device 30a that stores programs and maps related to the control of the electric motor 14. The memory device 30a includes a random access memory (RAM) and a read only memory (ROM). The control device 30 has one or more microprocessors that execute the programs.

[0034] The control device 30 controls the electric motor 14 based on the pedal force detected by the pedal force sensor 41 and the vehicle speed detected by the vehicle speed sensor 42. The memory device 30a stores in advance a map that defines the assist ratio according to the vehicle speed, conditions for changing the control mode of the electric motor 14, and the like.

[0035] The assist ratio is the ratio between the torque applied to the rear wheels 4 by the driver pressing the pedals 6 (herein referred to as pedal torque) and the torque transmitted from the electric motor 14 to the rear wheels 4 (herein referred to as motor torque). When the pedal torque is Tp and the motor torque is Tm, the assist ratio is expressed as "Tm / Tp." The assist ratio is, for example, a value greater than 0 and equal to or less than 2.

[0036] The control device 30 has a plurality of control modes for the electric motor 14, each having a different assist ratio. The control device 30 may have, for example, a strong mode, a medium mode, and a weak mode. The upper limit assist ratio defined for the strong mode is higher than the upper limit assist ratios defined for the other two control modes. The upper limit assist ratio defined for the medium mode is also higher than the upper limit assist ratio defined for the weak mode. These three control modes can be selected by a driver performing a mode selection operation on the UI device 50 (specifically, by turning on the up button 52a and the down button 52b). The number of control modes that can be selected by a driver is not limited to three, and may be two or more than three.

[0037] As will be described later, the control device 30 has a limit release mode in addition to the three control modes described above. The limit release mode is a control mode that achieves a higher assist ratio than the three control modes described above within a predetermined vehicle speed range. The limit release mode is permitted only when the driver satisfies certain conditions.

[0038] The storage device 30a stores information (assist ratio specifying information) that specifies the assist ratio according to the vehicle speed for each control mode. As the assist ratio specifying information, for example, one or more maps that associate the vehicle speed with the assist ratio are used. The control modes and assist ratio specifying information of the control device 30 will be described in detail later.

[0039] [UI device] As shown in FIG. 2, the bicycle 100 has a user interface device (UI device) 50. The UI device 50 has, for example, input buttons and indicators. FIG. 3 is a diagram showing an example of the UI device 50. As shown in FIG. 3, the UI device 50 may include, as examples of input buttons, an up button 52a, a down button 52b, a display selection button 52c, a light control button 52d, and a power button 52e. The input buttons 52a to 52e input signals (on / off signals) to the control device 30 in response to their operation.

[0040] The up button 52a and the down button 52b are input buttons that accept a mode selection operation by the driver. The up button 52a is a button for instructing a transition to a mode with a high assist ratio. Specifically, the up button 52a is a button for instructing a transition from weak mode to medium mode, and from medium mode to strong mode. The down button 52b is a button for instructing a transition to a mode with a low assist ratio. Specifically, the down button 52b is a button for instructing a transition from strong mode to medium mode, and from medium mode to weak mode.

[0041] The input button that accepts the mode selection operation is not limited to the example shown in Fig. 3. For example, the UI device 50 may have a plurality of input buttons that respectively correspond to a plurality of control modes (strong mode, medium mode, weak mode) that can be selected by any driver.

[0042] The bicycle 100 has a headlight (not shown). The light control button 52d is a button for turning the headlight on and off. The power button 52e is a button for turning on and off the power supply to the control device 30 and the motor drive device 13.

[0043] The UI device 50 may also have, as indicators, mode indicators 53a to 53c, a restriction release indicator 53d, a numerical indicator 53e, and a remaining battery level indicator 53f. The mode indicators 53a to 53c are indicators for indicating the currently selected control mode. The three mode indicators 53a to 53c correspond to the three control modes described above, namely, the strong mode, the medium mode, and the weak mode, respectively.

[0044] As described above, the control device 30 has a limit release mode as a control mode for the electric motor 14. The limit release indicator 53d is an indicator that shows that the limit release mode has been selected. When the limit release mode is selected, the limit release indicator 53d may, for example, light up or flash.

[0045] The battery remaining capacity indicator 53f displays an icon image according to the remaining capacity of the battery 15. The numeric indicator 53e is an indicator for displaying numeric information such as the current vehicle speed and the remaining battery capacity. The display selection button 52c is a button for selecting information (for example, vehicle speed and remaining battery capacity) to be displayed on the numeric indicator 53e.

[0046] The indicators 53a to 53d and 53f may be configured with LEDs (Light Emitting Diodes). The numeric indicator 53e may be configured with a liquid crystal display device, an organic EL display device, or the like. The buttons 52a to 52e may include switches mounted on a circuit board. Alternatively, the UI device 50 may be a display device equipped with a touch sensor that detects the position of the driver's finger.

[0047] [Control details] 4 is a block diagram showing the functions of the control device 30. The control device 30 has a motor control unit 31, a mode selection unit 32, and a mode guide unit 33. These functions are realized by the microprocessor constituting the control device 30 executing a program stored in the storage device 30a.

[0048] [Motor control unit] As described above, the control device 30 has a plurality of control modes (strong mode, medium mode, weak mode) that can be selected by any driver as the control mode for the electric motor 14. The number of control modes may be less than three or more than three. A plurality of pieces of assist ratio specification information may be stored in the storage device 30a in correspondence with the plurality of control modes, respectively.

[0049] Each piece of assist ratio specifying information specifies the assist ratio in correspondence with the vehicle speed. Each piece of assist ratio specifying information may specify the assist ratio in correspondence with not only the vehicle speed but also the pedaling force. For example, the assist ratio may be specified so that it decreases according to the vehicle speed in a vehicle speed range higher than a certain vehicle speed. Furthermore, when the pedaling force is small, the assist ratio may be specified so that it decreases as the pedaling force decreases.

[0050] A map may be used as the assist ratio defining information. For example, the assist ratio defining information may be a map that defines an assist ratio in correspondence with vehicle speed and pedal force. In this case, the map that defines the assist ratio may be made up of multiple maps. For example, each piece of assist ratio defining information may be made up of a first map that associates a basic assist ratio with pedal force, and a second map that associates a coefficient by which the basic assist ratio obtained from the first map is multiplied with vehicle speed. In this case, the assist ratio can be expressed by the following equation. Assistance ratio = Basic assistance ratio x coefficient Alternatively, the assist ratio may be associated only with the vehicle speed. In this case, the vehicle speed and the assist ratio may be directly associated in a map. Also, the assist ratio does not necessarily have to be defined in a map. For example, the storage device 30a may store an arithmetic expression that defines the assist ratio according to the vehicle speed.

[0051] The motor control unit 31 refers to the assist ratio defining information corresponding to the selected control mode and calculates the assist ratio according to the vehicle speed detected by the vehicle speed sensor 42. Furthermore, in a bicycle in which the assist ratio is defined according to the vehicle speed and pedaling force, the motor control unit 31 refers to the assist ratio defining information corresponding to the selected control mode and calculates the assist ratio according to the pedaling force detected by the pedaling force sensor 41 and the vehicle speed detected by the vehicle speed sensor 42. The motor control unit 31 then calculates an assist force according to the detected pedaling force and the assist ratio based on the output of the pedaling force sensor 41, and outputs a command value according to the assist force to the motor drive device 13. The motor drive device 13 receives power from the battery 15 and supplies a current according to the command value to the electric motor 14.

[0052] [Assistance ratio specified in the assist ratio specification information] FIG. 5 is a diagram illustrating an example of an assist ratio defined by the assist ratio defining information. In this diagram, the horizontal axis represents vehicle speed, and the vertical axis represents the assist ratio. This diagram shows an example of the upper limit of the assist ratio (upper limit assist ratio) that the control device 30 achieves at each vehicle speed. In this diagram, lines E1 (E11-E12), E2, and E3 respectively show examples of the relationship between vehicle speed and upper limit assist ratio in three control modes (strong mode, medium mode, and weak mode).

[0053] The motor control unit 31 calculates the upper limit assist ratio exemplified in Fig. 5 or an assist ratio smaller than the upper limit assist ratio, and outputs a current command value corresponding to this calculated assist ratio to the motor drive device 13. For example, when the pedaling force is larger than a threshold value, the motor control unit 31 outputs a current command value corresponding to the upper limit assist ratio exemplified in Fig. 5 to the motor drive device 13. On the other hand, when the pedaling force is smaller than the threshold value, the motor control unit 31 may output a current command value corresponding to an assist ratio smaller than the upper limit assist ratio exemplified in Fig. 5 to the motor drive device 13. In this case, the calculated assist ratio may decrease as the pedaling force decreases.

[0054] As shown by solid line E11, the assist ratio specification information for the strong mode specifies a constant upper limit assist ratio R1 in the vehicle speed range from 0 to vehicle speed V1. Furthermore, as shown by solid line E12 in Fig. 5, the assist ratio specification information for the strong mode specifies an upper limit assist ratio that decreases as the vehicle speed increases in a vehicle speed range higher than vehicle speed V1, and becomes 0 at vehicle speed V2. As shown by solid lines E2 and E3, the assist ratio specification information for the medium and weak modes specifies constant upper limit assist ratios R2 and R3 in the vehicle speed range from 0 to vehicle speed V1, and specifies an upper limit assist ratio that decreases as the vehicle speed increases in a vehicle speed range higher than vehicle speed V1, and becomes 0 at vehicle speed V2.

[0055] As shown in this figure, the upper limit assist ratios of the three modes, when compared at the same vehicle speed, are strong mode > medium mode > weak mode. The upper limit assist ratio R1 of the strong mode, which is defined for a vehicle speed range lower than vehicle speed V1, is the largest among the upper limit assist ratios set for the multiple control modes selectable by a mode selection operation on the UI device 50 (specifically, by turning on the up button 52a and the down button 52b). Furthermore, even in a vehicle speed range higher than vehicle speed V1, the upper limit assist ratio of the strong mode (diagonal solid line E12) is the largest among the upper limit assist ratios of the three control modes when compared at the same vehicle speed.

[0056] 5 is merely an example and may be changed as appropriate. For example, the vehicle speed at which the upper limit assist ratio in the medium mode and / or weak mode starts to decrease may be different from the vehicle speed V1 at which the upper limit assist ratio in the strong mode starts to decrease. For example, the vehicle speed at which the upper limit assist ratio in the medium mode and / or weak mode starts to decrease may be higher than the vehicle speed V1. Even in this case, the upper limit assist ratio in the medium mode and / or weak mode does not exceed the upper limit assist ratio in the strong mode (diagonal solid line E12).

[0057] In bicycle 100, a map is defined for each of the multiple control modes. However, a common map may be used across multiple control modes. For example, a value obtained from the map may be used as the assist ratio in the strong mode, while a value obtained by correcting the value obtained from the map may be used as the assist ratio in the medium mode or weak mode. For example, the correction may be performed by multiplying the value obtained from the map by a correction coefficient K (K<1). In this case, the bicycle speed and the assist ratio are associated using this correction coefficient K and the calculation formula.

[0058] [Mode selection section] The mode selection unit 32 selects one of three control modes based on a mode selection operation performed by the driver on the UI device 50. In the example shown in Fig. 3, the UI device 50 has an up button 52a and a down button 52b. For example, when the down button 52b is pressed while the strong mode is selected, the mode selection unit 32 selects the medium mode, and when the down button 52b is pressed while the medium mode is selected, the mode selection unit 32 selects the weak mode. Furthermore, when the up button 52a is pressed while the weak mode is selected, the mode selection unit 32 selects the medium mode, and when the up button 52a is pressed while the medium mode is selected, the mode selection unit 32 selects the strong mode.

[0059] [Unrestricted Mode] The control device 30 has a limit release mode as one of its control modes. Assist ratio specification information corresponding to the limit release mode may be stored in the storage device 30a. FIG. 6A is a diagram showing an example of an upper limit assist ratio specified by the assist ratio specification information for the limit release mode. In FIG. 6A, the solid line E4 represents the upper limit assist ratio for the limit release mode, and the dashed lines E1, E2, and E3 represent the upper limit assist ratios for the strong mode, medium mode, and weak mode, respectively.

[0060] In the restriction release mode shown in FIG. 6A, for a vehicle speed range higher than vehicle speed V1, an upper limit assist ratio that is higher than the upper limit assist ratio of the strong mode (solid line E12, see FIG. 5) is defined when compared at the same vehicle speed. More specifically, for a vehicle speed range higher than vehicle speed V3, which is higher than vehicle speed V1, an upper limit assist ratio that decreases as the vehicle speed increases is defined (solid line E42). Then, as in the strong mode, the upper limit assist ratio is 0 at vehicle speed V2. For a vehicle speed range lower than vehicle speed V3, an upper limit assist ratio that is the same as the upper limit assist ratio R1 of the strong mode described above is defined (solid line E41).

[0061] 6B to 6D are diagrams illustrating other examples of assist ratio definition information referenced in the restriction release mode. These diagrams show the upper limit of the assist ratio (i.e., upper limit assist ratio) that can be obtained at each vehicle speed in the restriction release mode.

[0062] 6B, a constant upper limit assist ratio may be defined regardless of the vehicle speed up to the upper limit of the vehicle speed (vehicle speed V2) at which assistance is provided by the electric motor 14. More specifically, an upper limit assist ratio R1 for the strong mode may be defined within the vehicle speed range from 0 to V2.

[0063] In the example shown in FIG. 6C, an upper limit assist ratio R1 for the strong mode is defined for a vehicle speed range lower than vehicle speed V1. An upper limit assist ratio (solid line E42) is defined that decreases as the vehicle speed increases in a vehicle speed range higher than vehicle speed V1. That is, the decrease in the upper limit assist ratio begins at vehicle speed V1, as in the assist ratio definition information for the strong mode. This upper limit assist ratio (solid line E42) is higher than the upper limit assist ratio (dashed line E12) for the strong mode defined for the same vehicle speed range. An upper limit assist ratio R4 greater than 0 is also defined for the upper limit of the vehicle speed (vehicle speed V2) at which assistance by the electric motor 14 is performed, and 0 is defined as the upper limit assist ratio for a vehicle speed range higher than vehicle speed V2. Unlike the example shown in FIG. 6C, an upper limit assist ratio greater than 0 may also be defined for a vehicle speed range higher than vehicle speed V2.

[0064] In the example shown in FIG. 6D, an upper limit assist ratio R1 for the strong mode is defined for a vehicle speed range lower than vehicle speed V1. An upper limit assist ratio (solid line E42) is defined that decreases as the vehicle speed increases in a vehicle speed range higher than vehicle speed V1. That is, the decrease in the upper limit assist ratio starts from vehicle speed V1, as in the assist ratio definition information for the strong mode. Also, in a vehicle speed range higher than vehicle speed V4, an upper limit assist ratio (solid line E43) is defined that decreases more significantly as the vehicle speed increases. The slope of solid line E43 is greater than the slope of solid line E42. That is, the rate of decrease in the upper limit assist ratio defined for a vehicle speed range higher than vehicle speed V4 is greater than the rate of decrease in the upper limit assist ratio defined for the vehicle speed range from vehicle speed V1 to V4.

[0065] Note that the memory device 30a does not need to store a map for the restriction release mode. In this case, the motor control unit 31 may use a map of a control mode permitted for any driver to achieve the assist ratio described with reference to FIGS. 6A to 6D. Furthermore, a map does not need to be used to achieve the assist ratio described with reference to FIG. 6B. The motor control unit 31 may use a fixed value R1 as the assist ratio.

[0066] [Authentication section] As shown in FIG. 4, the mode selection unit 32 has an authentication unit 32b (see FIG. 4) that executes authentication processing for the driver. The authentication unit 32b determines whether or not authentication of the driver is successful. If authentication is successful, the mode selection unit 32 allows selection of the restriction release mode. When the restriction release mode is selected, the motor control unit 31 refers to the assist ratio specification information for the restriction release mode (solid line E4 in FIGS. 6A to 6D) and calculates the assist ratio corresponding to the current vehicle speed (and pedal force).

[0067] The processing by the authentication unit 32b is executed, for example, as follows. The bicycle 100 has a UI device 50. The UI device 50 has a plurality of input buttons (input units) 52a-52e. When a predetermined authentication operation is performed using the plurality of input buttons 52a-52e, the authentication unit 32b determines that the authentication has been successful (i.e., determines that the rider is authorized) and allows the rider to select the restriction release mode. In other words, when the rider inputs a predetermined password using the input buttons 52a-52e, the authentication unit 32b determines that the authentication has been successful.

[0068] The authentication operation includes, for example, pressing a plurality of input buttons in a predetermined sequence. That is, when a predetermined plurality of input buttons 52a to 52e are turned on (pressed) in a predetermined sequence, the authentication unit 32b determines that authentication has been successful. The authentication operation may include pressing a plurality of input buttons simultaneously and / or pressing any of the input buttons for a long time (for example, for several seconds or more).

[0069] 3, the UI device 50 has five input buttons 52a to 52e. The authentication unit 32b may use only some of the input buttons 52a to 52e included in the UI device 50. For example, the authentication unit 32b may use only the up button 52a and the down button 52b in the authentication process.

[0070] According to the processing of authentication unit 32b, only riders who know how to perform the authentication operation are permitted to use the limit-release mode, which provides an assist ratio higher than that of the strong mode. For example, only riders who are accustomed to riding bicycle 100 (e.g., the owner of bicycle 100) are permitted to ride in limit-release mode, and riders who are renting bicycle 100 are restricted from riding in limit-release mode.

[0071] In the example described here, the input buttons used for the authentication operation also serve as input buttons for the driver to input instructions to the control device 30. For example, the input buttons (specifically, the up button 52a and the down button 52b) for instructing a change between multiple control modes (strong mode, medium mode, and weak mode) are used for the authentication operation. This makes it possible to avoid an increase in the number of parts required to accept the authentication operation.

[0072] [Authentication Operation Change] As shown in Fig. 4, the mode selection unit 32 may have an authentication operation setting unit 32c. The authentication operation setting unit 32c accepts a password set by the driver. That is, the authentication operation setting unit 32c accepts operation inputs by the driver (user) using the multiple input buttons 52a to 52e, sets an authentication operation that the authentication unit 32b determines to be appropriate based on the operation input, and records the authentication operation in the storage device 30a. The authentication unit 32b determines that authentication has been successful when the authentication operation recorded in the storage device 30a is performed on the input buttons 52a to 52e.

[0073] The mode selection unit 32 does not necessarily have to include the authentication operation setting unit 32c. In this case, the authentication unit 32b may determine, for example, whether or not the driver has performed an authentication operation that was set when the control device 30 was manufactured.

[0074] [Stop Unrestricted Mode] When a predetermined selection stop operation is performed on the input buttons 52a to 52e while the restriction release mode is selected, the mode selection unit 32 may stop the selection of the restriction release mode. Then, the mode selection unit 32 may select one of the control modes (strong mode, medium mode, and weak mode) permitted for any driver.

[0075] The selection stop operation may be simpler than the authentication operation. For example, the number of times the input button is pressed in the selection stop operation may be less than the number of times the input button is pressed in the authentication operation. As described above, examples of the authentication operation include pressing multiple input buttons in a predetermined order, pressing multiple input buttons simultaneously, and pressing any of the input buttons for a long time (for example, pressing for several seconds or more). In contrast, the selection stop operation may be an operation on any one of the input buttons.

[0076] The UI device 50 has a power button 52e. When the control device 30 is turned off by operating the power button 52e while the restriction release mode is selected, the mode selection unit 32 may stop selecting the restriction release mode. For example, when the restriction release mode is selected, information (a flag) indicating this may be recorded in the storage device 30a. When the control device 30 is turned off, the mode selection unit 32 may erase this information from the storage device 30a.

[0077] [Certification using certified parts or certified devices] The processing of the authentication unit 32b is not limited to the above-mentioned example using the UI device 50. The bicycle 100 may have a connection unit to which an authentication component or authentication device is connected. When such an authentication component or authentication device is connected to the connection unit, the authentication unit 32b may determine that authentication has been successful and allow the selection of the restriction release mode. The authentication component is, for example, a mechanical key or an electronic key, and the authentication device is, for example, a mobile terminal (e.g., a smartphone) owned by the rider (user).

[0078] If the authentication component is a mechanical key, bicycle 100 may have a key cylinder 43 (connection part) as shown in Figure 2. Key cylinder 43 has a switch that detects key operation (for example, turning the key) and inputs a signal indicating this to control device 30. When this signal is input from key cylinder 43, authentication unit 32b may determine that authentication has been successful and allow selection of restriction release mode.

[0079] If the authentication device is a mobile terminal, the bicycle 100 may have a communication module 44 (connection unit) instead of the key cylinder 43, as shown in FIG. 2. The communication module 44 is a communication module for two-way communication between the mobile terminal and the control device 30. The communication module 44 enables communication between the mobile terminal and the control device 30 in accordance with standards such as Wi-Fi (registered trademark) or Bluetooth (registered trademark). The authentication unit 32b may request authentication information from the mobile terminal. If the authentication information received from the mobile terminal matches the authentication information recorded in the storage device 30a, the authentication unit 32b may determine that authentication is successful and allow selection of the restriction release mode.

[0080] When such an authentication component or authentication device is used by the authentication unit 32b, the mode selection unit 32 may stop selecting the restriction release mode when the authentication component or authentication device is removed (when the connection is disconnected). For example, the mode selection unit 32 may stop selecting the restriction release mode when the key is removed from the key cylinder 43. When a mobile terminal is used as the authentication device, the mode selection unit 32 may request a response from the mobile terminal at predetermined time intervals. Then, when there is no response from the mobile terminal, the mode selection unit 32 may determine that the connection between the control device 30 and the mobile terminal has been disconnected, and may stop selecting the restriction release mode. Then, when the mode selection unit 32 stops selecting the restriction release mode, it may select one of the control modes (strong mode, medium mode, and weak mode) allowed for any driver.

[0081] [Start Unrestricted Mode] If the authentication by the authentication unit 32b is successful, the mode selection unit 32 may select the restriction release mode, and the motor control unit 31 may start the restriction release mode that achieves the upper limit assist ratio exemplified in FIGS. 6A to 6D.

[0082] Alternatively, the mode selection unit 32 may select the limit release mode when authentication by the authentication unit 32b is successful and a predetermined condition is met. For example, the mode selection unit 32 may select the limit release mode when authentication by the authentication unit 32b is successful and a predetermined operation is performed on the UI device 50. For example, the mode selection unit 32 may select the limit release mode when authentication by the authentication unit 32b is successful and the up button 52a is operated once or multiple times. Then, the motor control unit 31 may start control of the electric motor 14 based on the assist ratio specification information for the limit release mode (FIGS. 6A to 6D). In this way, control of the electric motor 14 in the limit release mode is executed in a situation where the driver clearly indicates the need for assistance in the limit release mode.

[0083] 7 is a flow chart showing an example of such processing by the mode selection unit 32. First, when the driver performs the above-mentioned authentication operation (operating the input button, connecting the key, or authenticating using the mobile terminal) and the authentication is successful, the authentication unit 32b stores information indicating that the authentication has been successful (hereinafter referred to as an authentication success flag) in the storage device 30a.

[0084] Thereafter, the mode selection unit 32 determines whether a predetermined operation (hereinafter referred to as a restriction release operation) has been performed (S101). Here, an example of the restriction release operation is operating the up button 52a one or more times while the strong mode is selected. When the restriction release operation is performed, the mode selection unit 32 determines whether an authentication success flag is stored in the storage device 30a (S102). If the authentication success flag is stored in the storage device 30a in S102, the mode selection unit 32 selects the restriction release mode (S103). As a result, the motor control unit 31 starts controlling the electric motor 14 based on the assist ratio specification information for the restriction release mode. On the other hand, if the authentication success flag is not stored in the storage device 30a in S102, the mode selection unit 32 ends the process while maintaining the current control mode (strong mode, medium mode, or weak mode).

[0085] The restriction release operation does not have to be an operation on the up button 52a, and the UI device 50 may be provided with a dedicated button for the restriction release operation.

[0086] When the down button 52b is operated while the restriction release mode is selected, the mode selection unit 32 may transition to the strong mode. This operation of the down button 52b corresponds to the selection stop operation described above.

[0087] As yet another example, when authentication by the authentication unit 32b is successful, a restriction release operation is performed on the UI device 50, and further, conditions regarding the pedaling ability of the rider are satisfied, the mode selection unit 32 may select the restriction release mode. The pedaling ability may be evaluated based on, for example, the output of the pedaling force sensor 41 or the cadence (the number of rotations of the crankshaft 7).

[0088] As yet another example, if authentication by authentication unit 32b is successful, a restriction release operation is performed on UI device 50, and further conditions regarding the riding environment of bicycle 100 are satisfied, mode selection unit 32 may select the restriction release mode. Conditions regarding the riding environment of bicycle 100 include, for example, the slope of the road on which bicycle 100 is riding and vibrations of bicycle 100. The slope of the road and vibrations of bicycle 100 can be detected, for example, by an acceleration sensor that outputs a signal corresponding to acceleration in the vertical direction.

[0089] [Mode guide] When the restriction release mode is selected, the mode guide unit 33 (see FIG. 4) indicates that the restriction release mode has been selected by the restriction release indicator 53d (see FIG. 3). For example, if the restriction release indicator 53d is an LED, the mode guide unit 33 lights up or flashes the restriction release indicator 53d.

[0090] In the example shown in FIG. 3, the UI device 50 has mode indicators 53a to 53c corresponding to the high mode, the medium mode, and the low mode, respectively. The mode guide unit 33 lights or blinks the mode indicators 53a to 53c corresponding to the currently selected control mode (high mode, medium mode, or low mode).

[0091] [Multiple assist ratio specification information available in the restriction解除 mode] A plurality of assist ratio specification information used in the restriction解除 mode may be stored in the storage device 30a. FIG. 8 is a diagram showing an example of such assist ratio specification information. In this figure, three upper limit assist ratios respectively indicated by solid lines E4, E5, and E6 are shown as examples of the upper limits of the assist ratios specified by the assist ratio specification information referred to in the restriction解除 mode. Hereinafter, the control mode in which the upper limit assist ratio of the solid line E4 is allowed is referred to as the "first restriction解除 mode", the control mode in which the upper limit assist ratio of the solid line E5 is allowed is referred to as the "second restriction解除 mode", and the control mode in which the upper limit assist ratio of the solid line E6 is allowed is referred to as the "third restriction解除 mode".

[0092] As shown in FIG. 8, the assist ratio specification information (solid line E4) of the first control解除 mode specifies an upper limit assist ratio higher than the upper limit assist ratio of the strong mode in a vehicle speed range higher than the vehicle speed V1. This assist ratio specification information specifies the upper limit assist ratio R1 of the strong mode in a vehicle speed range lower than the vehicle speed V3, and specifies an upper limit assist ratio that decreases as the vehicle speed increases in a vehicle speed range higher than the vehicle speed V3.

[0093] The assist ratio specification information (solid line E5) of the second control解除 mode specifies an upper limit assist ratio corresponding to the upper limit assist ratio R2 of the medium mode for a vehicle speed range lower than the vehicle speed V3, and specifies an upper limit assist ratio that decreases as the vehicle speed increases for a vehicle speed range higher than the vehicle speed V3. Further, this assist ratio specification information specifies an upper limit assist ratio higher than the upper limit assist ratio of the strong mode in a vehicle speed range higher than the vehicle speed V6 (V1 < V6 < V3).

[0094] The assist ratio regulation information (solid line E6) in the third control release mode defines the upper limit assist ratio corresponding to the upper limit assist ratio R3 in the weak mode for a vehicle speed range lower than the vehicle speed V3, and defines an upper limit assist ratio that decreases as the vehicle speed increases for a vehicle speed range higher than the vehicle speed V3. Also, this assist ratio regulation information defines an upper limit assist ratio higher than the upper limit assist ratio in the strong mode for a vehicle speed range higher than the vehicle speed V7 (V3 < V7 < V2).

[0095] The upper limit assist ratios (solid lines E4, E5, and E6) defined by these three assist ratio regulation informations in this way have a vehicle speed range in which an assist ratio higher than the assist ratio in the strong mode is defined.

[0096] Note that the number of assist ratio regulation informations available in the restriction release mode is not limited to three, and may be two or four or more. The upper limit assist ratio defined by the assist ratio regulation information used in the restriction release mode in a vehicle speed range lower than the vehicle speed V3 does not necessarily have to correspond to the upper limit assist ratios R1, R2, and R3 in the strong mode, medium mode, and weak mode, respectively.

[0097] As shown in FIG. 8, when a plurality of assist ratio regulation informations are defined for the restriction release mode, after the authentication by the authentication unit 32b is successful, the mode selection unit 32 may change the assist ratio regulation information (solid lines E4, E5, and E6) used in the restriction release mode based on the driver's operation input. FIG. 9 is a diagram showing an example of such processing by the mode selection unit 32.

[0098] The authentication unit 32b determines whether the authentication is successful (S201). Here, if the authentication is successful, the mode selection unit 32 selects one of the three above-described restriction release modes (the three assist ratio regulation informations that define the upper limit assist of the solid lines E4, E5, and E6 in FIG. 8) according to a predetermined rule (S202).

[0099] For example, if authentication is successful in S201, the mode selection unit 32 may select a control mode corresponding to the control mode (strong mode, medium mode, or weak mode) that was selected immediately before authentication was successful. Specifically, if the strong mode was selected immediately before authentication was successful, the mode selection unit 32 may select the first restriction release mode (solid line E4 in FIG. 8 ) that specifies the highest upper limit assist ratio among the three restriction release modes. If the medium mode was selected immediately before authentication was successful, the mode selection unit 32 may select the second restriction release mode (solid line E5 in FIG. 8 ) that specifies the middle upper limit assist ratio among the three restriction release modes. If the low mode was selected immediately before authentication was successful, the mode selection unit 32 may select the third restriction release mode (solid line E6 in FIG. 8 ) that specifies the smallest upper limit assist ratio among the three restriction release modes. When the mode selection unit 32 selects the strong mode, medium mode, or weak mode, the mode selection unit 32 stores information indicating this in the storage device 30a. Then, the mode selection unit 32 may use that information to execute the process of S201.

[0100] As another example, if authentication is successful in S201, the mode selection unit 32 may select a predetermined mode from three restriction release modes (first to third restriction release modes). For example, if authentication is successful, the mode selection unit 32 may select the second restriction release mode (solid line E5 in FIG. 8) that specifies a medium upper limit assist ratio from among the three restriction release modes.

[0101] The mode selection unit 32 determines whether the up button 52a (see FIG. 3) has been operated (S203). If the up button 52a is operated (pressed), the mode selection unit 32 selects a stronger mode (i.e., closer to the first restriction release mode (solid line E4)) (S204). For example, if the up button 52a is operated while the third restriction release mode (solid line E6) is selected, the mode selection unit 32 selects the second restriction release mode (solid line E5). If the up button 52a is operated while the second restriction release mode (solid line E5) is selected, the mode selection unit 32 selects the first restriction release mode (solid line E4). If the first restriction release mode has already been selected, the processing of S204 does not need to be performed.

[0102] On the other hand, if the up button 52a has not been operated in S203, the mode selection unit 32 determines whether the down button 52b (see FIG. 3) has been operated (S205). If the down button 52b has been operated (pressed), the mode selection unit 32 selects a mode closer to weak (i.e., closer to the third restriction release mode (solid line E6)) (S206). For example, if the down button 52b is operated while the first restriction release mode (solid line E4) is selected, the mode selection unit 32 selects the second restriction release mode (solid line E5). If the down button 52b is operated while the second restriction release mode (solid line E5) is selected, the mode selection unit 32 selects the third restriction release mode (solid line E6). Note that if the third restriction release mode has already been selected, the processing in S206 does not need to be performed.

[0103] After the processes of S204 and S206, the mode selection unit 32 determines whether an operation for instructing to stop the selection of the restriction release mode (i.e., the above-mentioned selection stop operation) has been performed on the UI device 50 (S207). If the selection stop operation has been performed, the mode selection unit 32 stops the selection of the restriction release mode (S208) and selects one of the strong mode, medium mode, and weak mode according to a predetermined rule. On the other hand, if the selection stop operation has not been performed in S207, the mode selection unit 32 returns to S203 and continues the subsequent processes. Also, if the down button 52b has not been operated in S205, the mode selection unit 32 proceeds to the process of S207 without going through the process of S206. The above is an example of the process of the mode selection unit 32 related to the selection of the restriction release mode.

[0104] In the example shown in Fig. 8, a plurality of pieces of assist ratio specifying information (solid lines E4, E5, and E6) are provided for the restriction release mode. Therefore, after switching to the restriction release mode, the driver (user) can select the assist ratio specifying information (first to third restriction release modes) that will achieve the most desirable assist ratio. Furthermore, because authentication is performed before the selection of this assist ratio specifying information, only users who are suitable for use of the first to third restriction release modes can be permitted to use these restriction release modes.

[0105] It is not necessary for the storage device 30a to store three maps corresponding to the first to third limit release modes, respectively. For example, the storage device 30a may store only the map for the first limit release mode. In this case, when the second limit release mode is selected, the motor control unit 31 may calculate the assist ratio for the second limit release mode based on the assist ratio obtained from this map and the correction coefficient. Similarly, when the third limit release mode is selected, the motor control unit 31 may calculate the assist ratio for the third limit release mode based on the assist ratio obtained from this map and the correction coefficient.

[0106] [Second example: Using pedaling ability] Fig. 10 is a block diagram showing a modified example of the bicycle 100 proposed in this disclosure. Fig. 11 is a block diagram showing the functions of a modified example of the control device 30 proposed in this disclosure.

[0107] 11, the mode selection unit 32 includes a pedaling ability evaluation unit 32d. The pedaling ability evaluation unit 32d calculates an "ability evaluation value" that represents the pedaling ability of the driver. For example, when the calculated ability evaluation value is higher than a threshold value, the mode selection unit 32 allows the selection of the restriction release mode.

[0108] [Pedaling ability] Pedaling ability is evaluated based on the pedaling force detected by the pedaling force sensor 41, the cadence (the number of rotations of the crankshaft 7) detected by the crank rotation sensor 45 (see FIG. 10), and the like. FIG. 12 shows a three-dimensional map for converting the pedaling force and cadence into an ability evaluation value. Hereinafter, this map will be referred to as the "conversion map." In the conversion map, an ability evaluation value is associated with the cadence and the pedaling force. The ability evaluation value defined in the conversion map of FIG. 12 increases, for example, as the cadence increases. Similarly, the ability evaluation value defined in the conversion map increases, for example, as the pedaling force increases.

[0109] Pedaling ability may be evaluated based on left-right balance in addition to, or instead of, pedaling force and cadence. That is, the ability evaluation value described above may be calculated based on left-right balance. The bicycle 100 may include an acceleration sensor 46 (see FIG. 10) that outputs a signal corresponding to left-right acceleration, and an angle sensor 47 (see FIG. 10) that outputs a signal corresponding to the rotation angle of the handlebar stem 8 (see FIG. 1). Large changes in left-right acceleration or frequent changes in the rotation angle of the handlebar stem 8 may be evaluated as poor balance. Therefore, the pedaling ability evaluation unit 32d may calculate the ability evaluation value based on the output of the acceleration sensor 46 and / or the output of the angle sensor 47.

[0110] Furthermore, pedaling ability may be evaluated based on the rider's reaction speed to a load in addition to, or instead of, the three factors described above (pedaling force, cadence, and balance). That is, the ability evaluation value may be calculated based on the rider's reaction speed to a load. Bicycle 100 includes an acceleration sensor that outputs a signal corresponding to acceleration in at least one of the forward / backward and upward directions, and pedaling force sensor 41 described above. Pedaling ability evaluation unit 32d calculates the time difference between the occurrence of a load (e.g., the arrival of an uphill slope) and a change in pedaling force, based on, for example, the output of the acceleration sensor and the output of pedaling force sensor 41. If this difference is large, the rider's reaction speed to the load may be evaluated as low. Therefore, pedaling ability evaluation unit 32d may calculate the ability evaluation value based on this difference.

[0111] Pedaling ability may be evaluated not only based on the pedaling force, cadence, balance, and reaction speed described herein, but also based on the rider's explosive power and endurance, for example. The explosive power may be calculated based on the instantaneous magnitude of the pedaling force, and the endurance may be calculated based on the average value of the pedaling force over a predetermined period of time.

[0112] For example, the mode selection unit 32 allows the selection of the restriction-release mode when the calculated ability evaluation value is higher than a threshold value. Alternatively, the mode selection unit 32 may allow the selection of the restriction-release mode when the ability evaluation value remains higher than the threshold value for a predetermined period of time or more. With this control device 30, only drivers with high pedaling ability can be allowed to travel in the restriction-release mode.

[0113] [Start Unrestricted Mode] The mode selection unit 32 selects the restriction release mode when the calculated performance evaluation value is higher than a threshold value or when the performance evaluation value remains higher than the threshold value for a predetermined period of time or more. Then, the motor control unit 31 starts to control the electric motor 14 using the assist ratio specification information for the restriction release mode, for example, as described with reference to Figures 6A to 6D.

[0114] As another example, the mode selection unit 32 may select the limit release mode when a performance evaluation value higher than a threshold is calculated and a predetermined operation is performed on the UI device 50. For example, the mode selection unit 32 may select the limit release mode when a performance evaluation value higher than a threshold is calculated and the up button 52a is subsequently operated one or more times. Then, the motor control unit 31 may start control of the electric motor 14 based on the assist ratio specification information for the limit release mode. In this way, control of the electric motor 14 in the limit release mode is started in a situation where the driver clearly indicates the need for assistance in the limit release mode.

[0115] [Hysteresis] When the restriction release mode is selected, the mode selection unit 32 may determine whether to stop the selection of the restriction release mode. When the selection of the restriction release mode is stopped, the mode selection unit 32 may select any of the control modes permitted to the driver, such as the strong mode, the medium mode, or the weak mode.

[0116] The mode selection unit 32 may determine whether to stop the selection of the restriction release mode based on, for example, the ability evaluation value. In this case, hysteresis may be provided between the selection of the restriction release mode and the cancellation of the selection of the restriction release mode.

[0117] For example, when the performance evaluation value calculated while the strong mode is selected exceeds a first threshold N5, the mode selection unit 32 may stop selecting the strong mode and select the limit release mode. Furthermore, when the performance evaluation value calculated while the limit release mode is selected falls below a second threshold N6 that is lower than the first threshold N5, the mode selection unit 32 may stop selecting the limit release mode and return to the strong mode. This can prevent excessively frequent switching between the limit release mode and other control modes (strong mode, medium mode, weak mode).

[0118] [Variation of the vehicle speed at which the assist ratio starts to decrease] FIG. 13 is a diagram showing an example of an upper limit assist ratio defined by the assist ratio defining information used in the restriction release mode. This diagram shows upper limit assist ratios (solid lines E4, E5, and E6) defined by three pieces of assist ratio defining information used in the restriction release mode. The three pieces of assist ratio defining information shown in this diagram define upper limit assist ratios corresponding to the upper limit assist ratio R1 in the strong mode for vehicle speed ranges lower than vehicle speeds V7, V8, and V9. Furthermore, the upper limit assist ratio indicated by the solid line E4 decreases as the vehicle speed increases in a vehicle speed range higher than vehicle speed V7. The upper limit assist ratio indicated by the solid line E5 decreases as the vehicle speed increases in a vehicle speed range higher than vehicle speed V8. The upper limit assist ratio indicated by the solid line E6 decreases as the vehicle speed increases in a vehicle speed range higher than vehicle speed V9.

[0119] The mode selection unit 32 may select one of the above-described multiple assist ratio specifying information based on the calculated performance evaluation value. For example, when the performance evaluation value is within the range from the first threshold N1 to the second threshold N2 (N2>N1), the assist ratio specifying information (solid line E4) specifying the lowest assist ratio may be selected. When the performance evaluation value is within the range from the second threshold N2 to the third threshold N3 (N3>N2), the assist ratio specifying information (solid line E5) specifying a medium assist ratio may be selected. When the performance evaluation value is within the range from the third threshold N3 to the fourth threshold N4 (N4>N3), the assist ratio specifying information (solid line E6) specifying the highest assist ratio may be selected.

[0120] According to the processing of the mode selection unit 32, in the restriction release mode, the vehicle speeds V7, V8, and V9 (see FIG. 13) at which the upper limit assist ratio starts to decrease as the vehicle speed increases change depending on the pedaling ability of the driver (user). As a result, for example, for a driver with high pedaling ability, control of the electric motor 14 with a high assist ratio (for example, control based on assist ratio specification information that specifies the upper limit assist ratio indicated by the solid line E6) is executed.

[0121] [Third example: Use of driving environment] Fig. 14 is a block diagram showing a modified example of the bicycle 100 proposed in this disclosure. Fig. 15 is a block diagram showing the functions of a modified example of the control device 30 proposed in this disclosure.

[0122] 15, the mode selection unit 32 includes a driving environment determination unit 32e. The driving environment determination unit 32e determines whether or not to permit selection of the restriction release mode based on the driving environment.

[0123] The riding environment is the environment in which the bicycle 100 is riding. One example of the riding environment is the slope of the road on which the bicycle 100 is riding. The riding environment determination unit 32e may calculate the slope of the road based on the output of an acceleration sensor 48 (see FIG. 14 ), which outputs a signal corresponding to acceleration in the forward / backward or upward / downward direction, for example. The riding environment determination unit 32e may allow the selection of the restriction release mode when the slope of the road is greater than a threshold value.

[0124] Another example of the riding environment is the condition of the road surface on which the bicycle 100 is riding. For example, the bicycle 100 vibrates more on a gravel road. Therefore, the riding environment determination unit 32e may allow the selection of the restriction release mode when the vibration occurring in the bicycle 100 is smaller than a threshold value. The vibration of the bicycle 100 can be calculated based on the output of the acceleration sensor 48 (see FIG. 14), which outputs a signal corresponding to the acceleration in the vertical direction.

[0125] Another example of the riding environment is the load acting on the bicycle 100. When a large load is acting on the bicycle 100, even if a large torque is transmitted to the rear wheel 4, the change in vehicle speed (i.e., acceleration) is small. Therefore, the riding environment determination unit 32e calculates the load acting on the bicycle 100, for example, based on the torque transmitted to the rear wheel 4 and the change in vehicle speed. Here, the torque transmitted to the rear wheel 4 includes the torque transmitted from the pedals 6 and the torque transmitted from the electric motor 14. The torque transmitted from the pedals 6 can be detected by the pedal force sensor 41. The torque transmitted from the electric motor 14 to the rear wheel 4 can be calculated based on the current supplied from the motor drive device 13 to the electric motor 14.

[0126] As shown in FIG. 14, the drive system of the bicycle 100 may have a camera 49 for capturing images of the surroundings of the bicycle 100. Further examples of the riding environment may include the brightness, weather, and congestion of the surroundings of the bicycle 100. The riding environment determination unit 32e may detect the brightness of the surroundings from image data acquired by the camera 49. The brightness of the surroundings may be calculated based on the luminance of the image data. The riding environment determination unit 32e may detect the weather from the image data acquired by the camera 49. The riding environment determination unit 32e may detect the congestion of the surroundings from the image data acquired by the camera 49. The riding environment determination unit 32e may execute an image processing algorithm such as template matching to detect raindrops and obstacles (including nearby people).

[0127] 13, the storage device 30a may store a plurality of pieces of assist ratio defining information to be used in the restriction release mode. The mode selection unit 32 may select a map suited to the driving environment from the plurality of pieces of assist ratio defining information, based on the driving environment detected by the driving environment determination unit 32e.

[0128] [summary] As described above, the drive system of the electrically assisted bicycle 100 includes a user interface device 50 having an up button 52a and a down button 52b that accept a mode selection operation by the rider, a mode selection unit 32 that selects a first control mode corresponding to the mode selection operation from a plurality of first control modes (strong mode, medium mode, and weak mode) that have mutually different assist ratios and are selectable by the mode selection operation, and a motor control unit 31 that controls the electric motor 14 in the selected first control mode based on the vehicle speed detected by the vehicle speed sensor 42. The motor control unit 31 includes a plurality of first control modes and a limit release mode as control modes for the electric motor 14. For the plurality of first control modes and the limit release mode, an upper limit assist ratio, which is the upper limit of the assist ratio achieved by driving the electric motor 14, is specified by assist ratio specification information. The strong mode has the highest upper limit assist ratio specified among the plurality of first control modes. Furthermore, the upper limit assist ratio in the strong mode is specified to decrease as the vehicle speed increases in a vehicle speed range higher than a first vehicle speed V1. In the limit release mode, a higher upper limit assist ratio is specified than in the strong mode when compared at the same vehicle speed in a vehicle speed range higher than the first vehicle speed V1. With this drive system, by using the limit release mode, it is possible to achieve a higher assist ratio than the multiple first control modes selectable by the mode selection operation.

[0129] (1) In the first example described with reference to Figures 2 to 9, the mode selection unit 32 allows the selection of the restriction release mode on the condition that the authentication of the driver is successful. According to this drive system, the use of the restriction release mode is permitted only for drivers who have been successfully authenticated.

[0130] (2) In the second example described with reference to Figures 10 to 13, the mode selection unit 32 allows the selection of the restriction release mode when the user's pedaling ability satisfies a predetermined condition. According to this drive system, the restriction release mode can be used only by drivers whose pedaling ability satisfies the predetermined condition.

[0131] (3) In the third example described with reference to Figures 14 and 15, the mode selection unit 32 allows the driver to select the restriction release mode when the driving environment satisfies certain conditions. According to this drive system, the driver can use the restriction release mode only in driving environments that satisfy certain conditions.

[0132] (4) In the strong mode, assist ratio specification information (FIG. 5) that associates vehicle speed with assist ratio is used, and in the limit release mode, assist ratio specification information (FIGS. 6A to 6D, 8, and 13) that associates vehicle speed with assist ratio is used. The assist ratio specification information in the strong mode specifies a first assist ratio R1 as the upper limit assist ratio for a vehicle speed range lower than a first vehicle speed V1, and specifies an upper limit assist ratio that decreases as the vehicle speed increases for a vehicle speed range higher than the first vehicle speed V1. The assist ratio specification information in the limit release mode specifies an assist ratio that is higher than the upper limit assist ratio specified in the strong mode when compared at the same vehicle speed for a vehicle speed range higher than the first vehicle speed V1.

[0133] (5) The upper limit assist ratio in the strong mode is the first assist ratio R1 in a vehicle speed range lower than the first vehicle speed V1. As explained with reference to FIG. 6A etc., the upper limit assist ratio defined in the restriction release mode is the first assist ratio R1 in at least a part of the vehicle speed range higher than the first vehicle speed V1.

[0134] (6) As explained with reference to Figure 6A, etc., the upper limit assist ratio specified for the restriction release mode decreases as the vehicle speed increases in the vehicle speed range higher than the second vehicle speed V3, which is higher than the first vehicle speed V1.

[0135] (7) In a first example, the user interface device 50 (FIG. 3) has a plurality of input buttons 52a-52e that accept driver operation. When a predetermined authentication operation is performed on the plurality of input buttons 52a-52e, the mode selection unit 32 determines that the authentication is successful and allows the selection of the restriction release mode. This allows the authentication operation to be performed without using a dedicated device or component.

[0136] (8) As described with reference to Fig. 4, in the first example, the mode selection unit 32 may have an authentication operation setting unit 32c that sets a predetermined authentication operation based on the driver's operation of the multiple input buttons 52a to 52e. This allows the user to change the authentication operation as needed.

[0137] (9) In the first example, the input buttons used in the authentication process include a button for the driver to switch between a plurality of first control modes (strong mode, medium mode, weak mode). This can prevent an increase in the number of parts in the user interface device. A button may be included for the driver to switch between strong and weak modes.

[0138] (10) In the first example, when a predetermined selection stop operation is performed on the input buttons 52a to 52e while the restriction release mode is selected, the mode selection unit 32 stops the selection of the restriction release mode. This allows the driver to easily return to one of the first control modes.

[0139] (11) In the first example, the drive system has a connection unit (key cylinder 43, communication module 44) for connecting an authentication device or authentication component. When the authentication device or authentication component is connected to the connection unit, the mode selection unit 32 determines that authentication has been successful and allows the selection of the restriction release mode. Here, the authentication device is, for example, a mobile terminal held by the bicycle owner, and the authentication component is, for example, a mechanical key or electronic key.

[0140] (12) In the second example, the mode selection unit 32 determines whether to allow the selection of the restriction release mode by using at least one of the force acting on the pedal 6, the rotation speed of the crankshaft 7, the left-right balance, and the reaction speed to the load as the user's pedaling ability.

[0141] (13) In the second example, the vehicle speed (V7, V8, V9) at which the upper limit assist ratio begins to decrease varies depending on the driver's pedaling ability, thereby providing a more comfortable ride.

[0142] (14) In a third example, the riding environment is at least one of the road gradient, road surface condition, load acting on the bicycle, brightness around the bicycle, weather, and traffic congestion.

[0143] The electrically assisted bicycle and its drive system proposed in this disclosure are not limited to the examples described above, and various modifications may be made. [Explanation of symbols]

[0144] 1: frame, 1a: head pipe, 1b: seat tube, 2: saddle, 3: front wheel, 4: rear wheel, 5: chain, 6: pedals, 7: crankshaft, 8: handle stem, 8a: front fork, 9: handle, 13: motor drive device, 14: electric motor, 15: battery, 20: drive unit, 21: reducer, 22: resultant force transmission mechanism, 30: control device, 30a: storage device, 31: motor control unit, 32: mode selection unit, 32b : Authentication unit, 32c: Authentication operation setting unit, 32d: Pedaling ability evaluation unit, 32e: Riding environment determination unit, 33: Mode guidance unit, 41: Pedaling force sensor, 42: Vehicle speed sensor, 43: Key cylinder, 44: Communication module, 45: Crank rotation sensor, 46: Acceleration sensor, 47: Angle sensor, 48: Acceleration sensor, 49: Camera, 50: User interface device (UI device), 52a: Up button, 52b: Down button, 52c: Display selection button, 52d: Light control button, 52e: Power button, 53a to 53c: Mode indicator, 53d: Restriction release indicator, 53e: Numeric indicator, 53f: Battery remaining capacity indicator, 100: Electrically assisted bicycle.

Claims

1. a user interface device to be mounted on a bicycle, the user interface device having at least one input unit that accepts a mode selection operation by a rider; a mode selection unit that selects a first control mode corresponding to the mode selection operation from a plurality of first control modes selectable by the mode selection operation; a motor control unit that controls the electric motor in the selected first control mode based on the vehicle speed detected by a sensor; and the motor control unit includes the plurality of first control modes and a second control mode as control modes of the electric motor, and an upper limit assist ratio that is an upper limit of an assist ratio realized by driving the electric motor is defined for each of the plurality of first control modes and the second control mode, one of the plurality of first control modes is specified with the highest upper limit assist ratio among the plurality of first control modes, and the upper limit assist ratio of the one of the plurality of first control modes is specified to decrease as the vehicle speed increases in a vehicle speed range higher than a first vehicle speed; The second control mode is defined, in a vehicle speed range higher than the first vehicle speed, as an upper limit assist ratio higher than the one of the plurality of first control modes when compared at the same vehicle speed, The mode selection unit executes an authentication process for the driver, and if the authentication is successful, stores information indicating the success in a storage device. Thereafter, if a predetermined operation is performed on the user interface device and the information is stored in the storage device, the mode selection unit selects the second control mode. Electric assist bicycle drive system.

2. a user interface device having at least one input unit that accepts a mode selection operation by a driver; a mode selection unit that selects a first control mode corresponding to the mode selection operation from a plurality of first control modes selectable by the mode selection operation; a motor control unit that controls the electric motor in the selected first control mode based on the vehicle speed detected by a sensor; and the motor control unit includes the plurality of first control modes and a second control mode as control modes of the electric motor, and an upper limit assist ratio that is an upper limit of an assist ratio realized by driving the electric motor is defined for each of the plurality of first control modes and the second control mode, one of the plurality of first control modes is specified with the highest upper limit assist ratio among the plurality of first control modes, and the upper limit assist ratio of the one of the plurality of first control modes is specified to decrease as the vehicle speed increases in a vehicle speed range higher than a first vehicle speed; The second control mode is defined, in a vehicle speed range higher than the first vehicle speed, as an upper limit assist ratio higher than the one of the plurality of first control modes when compared at the same vehicle speed, the mode selection unit allows selection of the second control mode when the pedaling ability of the user satisfies a predetermined condition; The mode selection unit uses at least one of the force acting on the pedal, the number of rotations of the pedal, the balance of the posture of the electrically assisted bicycle in the left-right direction, and the reaction speed of the rider to the load acting on the electrically assisted bicycle as the pedaling ability of the user, and allows selection of the second control mode when at least one of the above satisfies the predetermined condition. Electric assist bicycle drive system.

3. In the one of the plurality of first control modes, first assist ratio defining information that associates a vehicle speed with an assist ratio is utilized, In the second control mode, second assist ratio defining information that associates a vehicle speed with an assist ratio is utilized, the first assist ratio definition information defines a first assist ratio as the upper limit assist ratio for a vehicle speed range lower than the first vehicle speed, and defines the upper limit assist ratio that decreases as the vehicle speed increases for a vehicle speed range higher than the first vehicle speed, The second assist ratio specifying information specifies an upper limit assist ratio that is higher than the upper limit assist ratio specified by the first assist ratio specifying information when compared at the same vehicle speed, for a vehicle speed range higher than the first vehicle speed.

3. A drive system for an electrically assisted bicycle according to claim 1 or 2.

4. the upper limit assist ratio defined in the one of the plurality of first control modes is a first assist ratio in a vehicle speed range lower than the first vehicle speed, The upper limit assist ratio defined in the second control mode is the first assist ratio in at least a part of a vehicle speed range higher than the first vehicle speed.

3. A drive system for an electrically assisted bicycle according to claim 1 or 2.

5. The upper limit assist ratio defined for the second control mode is higher than the first vehicle speed. In a vehicle speed range higher than the second vehicle speed, the value decreases as the vehicle speed increases.

3. A drive system for an electrically assisted bicycle according to claim 1 or 2.

6. the user interface device includes a plurality of input units that accept operations by a driver, including the at least one input unit; The mode selection unit determines that authentication has been successful when a predetermined authentication operation is performed on the plurality of input units, and selects the second control mode.

2. A drive system for an electrically assisted bicycle according to claim 1.

7. The vehicle further includes an authentication operation setting unit that sets the predetermined authentication operation based on the driver's operation on the plurality of input units.

7. A drive system for an electrically assisted bicycle according to claim 6.

8. The at least one input unit includes a button for a driver to switch between the plurality of first control modes.

7. A drive system for an electrically assisted bicycle according to claim 6.

9. The mode selection unit stops the selection of the second control mode when a predetermined selection stop operation is performed on the at least one input unit while the second control mode is selected.

2. A drive system for an electrically assisted bicycle according to claim 1.

10. Further, the authentication device or the authentication component may have a connection portion for connecting thereto. The mode selection unit determines that authentication has been successful when the authentication device or the authentication component is connected to the connection unit, and allows selection of the second control mode.

2. A drive system for an electrically assisted bicycle according to claim 1.

11. the upper limit assist ratio defined for the second control mode decreases in accordance with an increase in vehicle speed in a vehicle speed range that is higher than a second vehicle speed that is higher than the first vehicle speed, The second vehicle speed is changed in accordance with the pedaling ability of the driver.

3. A drive system for an electrically assisted bicycle according to claim 2.

12. An electrically assisted bicycle equipped with the drive system according to claim 1 or 2.

13. A control method for an electrically assisted bicycle having a user interface device with at least one input unit that accepts a mode selection operation by a rider, comprising: a mode selection step of selecting a first control mode corresponding to the mode selection operation from a plurality of first control modes selectable by the mode selection operation, the first control modes having mutually different assist ratios; and a motor control step of controlling the electric motor in the selected first control mode based on the vehicle speed detected by a sensor. Including, the motor control step includes the plurality of first control modes and a second control mode as control modes of the electric motor, and an upper limit assist ratio that is an upper limit of an assist ratio realized by driving the electric motor is defined for each of the plurality of first control modes and the second control mode; one of the plurality of first control modes is specified with the highest upper limit assist ratio among the plurality of first control modes, and the upper limit assist ratio of the one of the plurality of first control modes is specified to decrease as the vehicle speed increases in a vehicle speed range higher than a first vehicle speed; The second control mode is defined, in a vehicle speed range higher than the first vehicle speed, as an upper limit assist ratio higher than the one of the plurality of first control modes when compared at the same vehicle speed, In the mode selection unit step, an authentication process is performed for the driver, and if the authentication is successful, information indicating the success is stored in a storage device. Thereafter, if a predetermined operation is performed on the user interface device and the information is stored in the storage device, the second control mode is selected. How to control an electric assist bicycle.

14. a user having at least one input unit that accepts a mode selection operation by a driver; A control method for an electrically assisted bicycle having an interface device, comprising: a mode selection step of selecting a first control mode corresponding to the mode selection operation from a plurality of first control modes selectable by the mode selection operation, the first control modes having mutually different assist ratios; and a motor control step of controlling the electric motor in the selected first control mode based on a vehicle speed detected by a sensor, the motor control step includes the plurality of first control modes and a second control mode as control modes of the electric motor, and an upper limit assist ratio that is an upper limit of an assist ratio realized by driving the electric motor is defined for each of the plurality of first control modes and the second control mode; one of the plurality of first control modes is specified with the highest upper limit assist ratio among the plurality of first control modes, and the upper limit assist ratio of the one of the plurality of first control modes is specified to decrease as the vehicle speed increases in a vehicle speed range higher than a first vehicle speed; The second control mode is defined, in a vehicle speed range higher than the first vehicle speed, as an upper limit assist ratio higher than the one of the plurality of first control modes when compared at the same vehicle speed, the mode selection step allows selection of the second control mode when the pedaling ability of the user satisfies a predetermined condition; In the mode selection step, at least one of the force acting on the pedal, the number of rotations of the pedal, the balance of the posture of the electrically assisted bicycle in the left-right direction, and the reaction speed of the rider to the load acting on the electrically assisted bicycle is used as the pedaling ability of the user, and the second control mode is permitted to be selected when at least one of the above satisfies the predetermined condition. How to control an electric assist bicycle.

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