JP2014125193A - Power-assisted bicycle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a power-assisted bicycle capable of making an output of an assistive driving force more appropriate than a conventional one.SOLUTION: A power-assisted bicycle is designed to be driven with a principal driving force derived from human effort and an assistive driving force derived from an electric motor. The power-assisted bicycle includes input torque measurement means 18 that measures the principal driving force, assistive driving force determination means 19 that determines the assistive driving force dependent on the principal driving force detected by the input torque measurement means 18, illuminance measurement means 20 that measures ambient brightness, illuminance discrimination means 21 that compares the illuminance, which is measured by the illuminance measurement means 20, with a criterial illuminance so as to discriminate the magnitude relation between them, retardation control means 22 that retards the outputting initiation time of the assistive driving force with respect to the inputting initiation time of the principal driving force according to a result of discrimination by the illuminance discrimination means 21, and amount-of-fed current control means 23 that controls an amount of current, which is fed from a battery to the electric motor 15, according to the assistive driving force determined by the assistive driving force determination means 19.

Description

  The present invention relates to an electrically assisted bicycle, and more particularly to an electrically assisted bicycle that can make the output of auxiliary driving force more appropriate than before.

  In general, an electrically assisted bicycle detects a main driving force by a pedaling force of a person from a pedal by a torque measuring means such as a torque sensor, and generates an auxiliary driving force corresponding to the main driving force by an electric motor such as an electric motor, By adding an auxiliary driving force to the main driving force, the vehicle can be driven easily. For example, the auxiliary driving force output from the electric motor is less than 2 with respect to the main driving force 1 when the vehicle speed is 0 to 10 km / h, and gradually increases depending on the vehicle speed between 10 km / h and 24 km / h. The auxiliary driving force is controlled to be zero at 24 km / h. Today, various improvements have been proposed for improving riding comfort and safety in such an electrically assisted bicycle.

  For example, in Patent Documents 1 to 3, a start time determination unit is provided, and when the start time determination unit determines that the bicycle is starting, the ratio (assist ratio) of the auxiliary drive force to the main drive force is calculated. There has been proposed an electrically assisted bicycle including an auxiliary driving force adjusting means which is enlarged. Further, in Patent Documents 4 to 6, a start time determining unit is provided, and when the start time determining unit determines that the bicycle is starting, the auxiliary driving force output by the electric motor is compared with the main driving force. There has been proposed a power-assisted bicycle having a delay control means for delaying. In this way, by increasing the assist ratio at the start of an electrically assisted bicycle, the pedal reaction force is abruptly increased at the start by reducing labor at the start or delaying the auxiliary drive force with respect to the main drive force. It prevents a weakening and enables a smooth start.

Japanese Patent Laid-Open No. 11-11375 JP 2001-88770 A JP-A-7-309283 JP 2002-264882 A JP-A-8-244672 JP-A-8-295285

  According to the electrically assisted bicycles described in Patent Documents 1 to 6, it is possible to improve the ride comfort and safety at the time of starting, but today the demand is further strengthened. Further, in the future, in order to further improve the performance of the electrically assisted bicycle in addition to safety and ride comfort, it is necessary to make full use of the auxiliary driving force adjusting means and the delay control means.

  Therefore, an object of the present invention is to provide an electrically assisted bicycle that can make the output of the auxiliary driving force more appropriate than before.

  As a result of diligent studies to solve the above problems, the present inventors have delayed the start of auxiliary driving force output relative to the start of input of main driving force in accordance with the surrounding brightness, thereby making it more difficult than before. The present inventors have found that an electrically assisted bicycle that can make the output of the auxiliary driving force more appropriate can be obtained, and have completed the present invention.

That is, the electrically assisted bicycle of the present invention is an electrically assisted bicycle configured to be driven by a main driving force by human power and an auxiliary driving force by an electric motor.
Input torque measuring means for detecting the main driving force, auxiliary driving force determining means for determining auxiliary driving force according to the main driving force detected by the input torque measuring means, and illuminance measurement for measuring ambient brightness Illuminance determination means for comparing the illuminance measured by the illuminance measurement means with a reference illuminance to determine a magnitude relationship, and at the start of output of the auxiliary driving force according to the result determined by the illuminance determination means And a current for controlling the amount of current supplied from the battery to the electric motor according to the auxiliary driving force determined by the auxiliary driving force determining means. And a supply amount control means.

  In the electrically assisted bicycle according to the present invention, when the illuminance detected by the illuminance measuring unit is I and the determination reference illuminance is Is, the delay time when the illuminance determining unit determines that I <Is is the illuminance determination. The delay time when the means determines that I ≧ Is may be greater than the delay time when the illuminance determination means determines that I <Is, and the delay time when the illuminance determination means determines that I ≧ Is It may be smaller than the time. In addition, the electrically assisted bicycle according to the present invention preferably includes auxiliary driving force adjusting means for adjusting the auxiliary driving force determined by the auxiliary driving force determining means.

  ADVANTAGE OF THE INVENTION According to this invention, the electrically assisted bicycle which can make the output of auxiliary drive force more appropriate than before can be provided.

1 is a side view of an electrically assisted bicycle according to a preferred embodiment of the present invention. It is a flowchart of the electric motor control of the electric assist bicycle of the present invention. It is an example of the graph which showed the driving force in the daytime according to this invention at night, (a) shows the case at the time of start, (b) shows the case at the time of constant speed driving, respectively. It is another example of the graph which showed the driving force at the time of start in the daytime and night according to the present invention, and (a) shows the start and end times of the auxiliary driving force at night and the input start of the main driving force. When delayed from the end, (b) delays the start of auxiliary driving force output at night from the start of input of main driving force at night, and ends the output of auxiliary driving force at the end of input of main driving force. The case where it is earlier is shown. It is an example of the graph which showed the driving force in the daytime at night when the auxiliary drive force adjustment means based on this invention was provided, (a) is at the time of start, (b) is the case at the time of constant speed driving, respectively. Show.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
FIG. 1 is a side view of a power-assisted bicycle 1 according to a preferred embodiment of the present invention. The vehicle body frame 2 includes a head tube 3, a down tube 4 that extends obliquely downward and rearward from the head tube 3, a seat tube 5 that extends obliquely upward and backward from the rear end of the down tube 4, and a rearward position from the vicinity of the lower end of the seat tube 5. A pair of left and right chain stays 6 that extend, and a pair of left and right seat stays 7 that connect the rear ends of both chain stays 6 and the upper portion of the seat tube 5 are provided. At the lower end of the head tube 3, there is a front fork 8 that extends obliquely downward and forward, and a front wheel 9 is rotatably attached to the lower end portion of the front fork 8. A handle 10 is attached to the upper end of the head pipe 3, and a saddle 11 is attached to the upper end of the seat tube 5. Further, a rear wheel 12 is rotatably attached to the rear end portion of the chain stay 6.

  The electrically assisted bicycle 1 of the present invention has a pedal 13 as in the case of a conventional electrically assisted bicycle, and the main driving force (torque due to the pedaling force) is transmitted to the chain 14 when the driver steps on the pedal 13 and rotates it. The driving force is transmitted to the rear wheel 12, and the rear wheel 12 is driven. In the illustrated electric assist bicycle 1, the electric motor 15 is mounted in the vicinity of the crankshaft 16, and a battery 17 that supplies electric power to the electric motor 15 is detachably attached to the rear of the seat tube 5. An electric motor that supplies auxiliary driving force to the rear wheels 12 is provided inside the electric motor 15.

  FIG. 2 shows a flowchart of the motor control of the electrically assisted bicycle 1 of the present invention. In the electric assist bicycle 1 of the present invention, an input torque measuring means 18 such as a torque sensor for measuring a main driving force is attached to, for example, a crankshaft 16, and the crankshaft 16 is attached to the crankshaft 16 by the input torque measuring means 18. Torque, which is the main driving force generated, is measured. Furthermore, the electrically assisted bicycle 1 of the present invention includes auxiliary driving force determining means 19 that determines auxiliary driving force according to the torque measured by the input torque measuring means 18. In the electrically assisted bicycle 1 of the present invention, the method employed in the conventional electrically assisted bicycle is adopted for the measurement of the torque by the input torque measuring means 18 and the determination of the auxiliary driving force by the auxiliary driving force determining means 19. be able to.

  The electric assist bicycle 1 of the present invention is measured by an illuminance measuring means 20 such as an illuminance sensor for measuring ambient brightness, and an illuminance measuring means 20 in addition to the input torque measuring means 18 and the auxiliary driving force determining means 19. The illuminance determination means 21 that compares the illuminance with the determination reference illuminance to determine the magnitude relationship, and delays the start of output of the auxiliary driving force from the start of input of the main driving force according to the result determined by the illuminance determination means 21 Current supply amount control means 23 for controlling the amount of current supplied from the battery to the electric motor 15 according to the auxiliary drive force determined by the delay control means 22 and the auxiliary drive force determination means 19 is provided.

  First, when the driver steps on the pedal and a main driving force is generated while the electric assist bicycle according to the present invention is traveling, the input torque measuring means 18 detects the main driving force (torque). The auxiliary driving force determining means 19 determines auxiliary driving according to the torque at this time, and the ambient brightness (illuminance I) is then measured by the illuminance measuring means 20. The illuminance determination means 21 compares the result with the determination reference illuminance Is to determine whether the illuminance I is darker than the determination reference illuminance Is. In accordance with the result, the delay control means 22 determines the delay time at the start of output of the auxiliary driving force relative to the start of input of the main driving force. Thereafter, a current corresponding to the auxiliary driving force adjusted by the auxiliary driving force determining means 19 is supplied from the battery to the electric motor 15 by the current supply amount control means 23, whereby the auxiliary driving force is output from the electric motor 15.

  In a conventional electric assist bicycle that delays the start of output of auxiliary driving force with respect to the start of input of main driving force, when the driver depresses the pedal to generate the main driving force, the input torque measuring means operates. Thus, the torque of the main driving force is detected, and the driving is performed by outputting the auxiliary driving force with a delay from the main driving force from the electric motor in accordance with the torque. However, in the conventional electrically assisted bicycle, the delay time of the output of the auxiliary driving force with respect to the input of the main driving force is the same at daytime or at night.

  Therefore, in the electrically assisted bicycle 1 of the present invention, the illuminance measurement means 20, the illuminance determination means 21, and the delay control means 22 are provided. In the electrically assisted bicycle 1 of the present invention, when the illuminance detected by the illuminance measurement means 20 is I and the determination reference illuminance is Is, the delay time when the illuminance determination means 21 determines that I <Is is the illuminance determination. The delay time may be longer when the means 20 determines that I ≧ Is, or may be shorter than the delay time when the illuminance determination means 20 determines that I ≧ Is. By adopting such a configuration, the output of the auxiliary driving force can be made more appropriate than before. Here, the delay time means a difference between the start of input of the main driving force and the start of output of the auxiliary driving force.

  For example, the delay time of the auxiliary driving force output at night (I <Is) can be made longer than the delay time of the auxiliary driving force output at daytime (I ≧ Is). In this state, the total driving force is smaller at night than in the daytime. As a result, the movement of the electrically assisted bicycle at night starts slowly, or the traveling speed decreases, making it easier to grasp the movement of the electrically assisted bicycle as viewed from the surroundings. In addition, since the movement of the electrically assisted bicycle becomes gentle, it becomes easier for the driver of the electrically assisted bicycle to pay attention to the surroundings, and safety during traveling is improved. Furthermore, since the traveling speed is suppressed, it is easy to take a danger avoiding operation, and it is possible to quickly cope with an emergency stop. Therefore, in the above example, the electrically assisted bicycle of the present invention is superior in safety during traveling at night and in a dark place as compared with the conventional electrically assisted bicycle. In the above example, the delay time of the auxiliary driving force in the daytime (I ≧ Is) is set to 0, and the output of the auxiliary driving force is delayed with respect to the main driving force only at night (I <Is). May be.

  Further, for example, the delay time of the auxiliary driving force input at night (I <Is) may be shorter than the delay time of the auxiliary driving force input at daytime (I ≧ Is). As a result, an increase in pedaling force can be suppressed, and the total driving force of the vehicle can be reduced by reducing the assist ratio.

  FIG. 3 is an example of a graph showing the driving force in the daytime and nighttime according to the present invention, wherein (a) shows the case of starting and (b) shows the case of constant speed running. As shown in FIG. 3 (a), when the electrically assisted bicycle starts, the auxiliary driving force output with a certain delay from the main driving force gradually decreases according to the acceleration, and the figure is shown when the vehicle is running at a constant speed. As shown in FIG. 3B, a constant auxiliary driving force is output with a certain delay from the main driving force. In the electrically assisted bicycle according to the present invention, the delay time may be set separately at the time of starting and at the constant speed. The start time of the electric assist bicycle can be set as appropriate according to the purpose of use. For example, when the speed is 5 km / h or less, the start time is 5 seconds from the start of movement. Further, when the assist is resumed from the assist stop state during traveling, it may be regarded as the time of starting. Further, the start time may be defined based on the number of peaks of the auxiliary driving force as shown in FIG. 3 and the integrated value of the auxiliary driving force.

  In the electrically assisted bicycle of the present invention, when the output of the auxiliary driving force is delayed by the delay control means 22, as shown in FIG. 3, only the start of the output of the auxiliary driving force is delayed and the main driving force becomes zero. In this case, the auxiliary driving force output may be set to zero. In this case, no auxiliary driving force is generated when no input torque due to pedaling force is applied (when pedaling force is not applied), so the input of auxiliary driving force feels natural and close to ordinary bicycles, and unintended assistance It is possible to prevent the danger of traveling due to the driving force.

  In the electrically assisted bicycle according to the present invention, the timing when the main driving force becomes zero and the timing when the output of the auxiliary driving force becomes zero may be shifted. FIG. 4 is another example of a graph showing the driving force at the start in the daytime and nighttime according to the present invention. FIG. 4A shows the main driving force at the start and end of output of the auxiliary driving force at nighttime. When the input is delayed from the start and end, (b) delays the start of auxiliary driving force output at night from the start of input of the main driving force and sets the auxiliary driving force output to the main driving force at night. The case where it is earlier than the end of the input is shown.

  As shown in FIG. 4A, when the output of the auxiliary driving force is delayed from the end of the input of the main driving force, as compared with the case where the input of the main driving force is completed. , Ride comfort will be better. On the other hand, as shown in FIG. 4B, the start of output of the auxiliary drive force is delayed from the start of input of the main drive force, and the end of output of the auxiliary drive force is made earlier than the end of input of the main drive force. In this case, since the total driving force per step (the sum of the main driving force and the auxiliary driving force in the figure) can be reduced, the driving force as a whole can be reduced. Safety is improved. In addition, since the auxiliary driving force at the end of the input of the main driving force can be reliably reduced to 0, unintended bicycle travel can be prevented and safety during night travel can be improved.

  In the electrically assisted bicycle according to the present invention, the delay control means 22 delays the start of the auxiliary driving force output from the start of the auxiliary driving force output in the daytime to the maximum output of the main driving force. For example, the main driving force may be delayed by several milliseconds to several hundred milliseconds.

  Moreover, in the electrically assisted bicycle 1 of the present invention, it is preferable to include auxiliary driving force adjusting means 24 for controlling the auxiliary driving force. FIG. 5 is an example of a graph showing the driving force in the daytime and nighttime when the auxiliary driving force adjusting means according to the present invention is provided, (a) at the time of start, (b) at the time of constant speed running. Each case is shown. As shown in the figure, by using the auxiliary driving force adjusting means 24 to limit the auxiliary driving force and lowering the assist ratio, the total driving force is reduced, and the movement start at the start of the electric assist bicycle at night is further moderated. can do. As a result, safety during night driving can be further improved.

  Further, in the electrically assisted bicycle according to the present invention, the delay control means 22 sets the brightness that serves as a reference for delaying the start of output of the auxiliary drive force relative to the start of input of the main drive force in a plurality of stages. (Criterion illuminance Isn: n = 1, 2, 3,...) It is also preferable to delay the start of output of the auxiliary driving force step by step as the surroundings become darker. For example, when the surroundings gradually become dark as in the evening, when there is only one point of brightness that serves as a reference for delaying the start of auxiliary driving force output relative to the start of input of main driving force, When the output start time of the auxiliary driving force is delayed, a situation occurs in which the pedal 13 suddenly becomes heavy, resulting in poor ride comfort. In contrast, if a plurality of brightness levels are set as references for delaying the start of auxiliary drive force output relative to the start of main drive force input, the auxiliary drive force gradually increases as the surroundings become darker. Since the output start time is delayed, it is possible to avoid a delay at the start of output of the sudden auxiliary driving force, and it is possible to avoid a situation that impairs the ride comfort.

  Furthermore, in the electrically assisted bicycle of the present invention, the brightness that serves as a reference for changing the assist ratio is set in a plurality of stages by the auxiliary driving force adjusting means 24 (determination reference illuminance Isn: n = 1, 2, 3 ...), it is also preferable to gradually reduce the output of the auxiliary driving force as the surroundings become darker. For the same reason as the delay control means 22, if a plurality of reference brightnesses for limiting the auxiliary driving force are set, the output of the auxiliary driving force may be limited step by step as the surroundings become darker. Therefore, it is possible to avoid the pedal from becoming suddenly heavy, and it is possible to avoid a situation that impairs the riding comfort.

  In the electrically assisted bicycle 1 of the present invention, when the auxiliary driving force adjusting unit 24 is provided, the auxiliary driving force adjusted by the auxiliary driving force adjusting unit 24 is 1 of the auxiliary driving force determined by the auxiliary driving force determining unit 19. It is preferably larger than / 2. This is because if the magnitude of the auxiliary driving force is equal to or less than ½ of the auxiliary driving force adjusted by the auxiliary driving force adjusting means 24, the driver may feel that a sufficient assist force is not obtained. On the other hand, the upper limit of the auxiliary driving force adjusted by the auxiliary driving force adjusting unit 24 may be less than the auxiliary driving force determined by the auxiliary driving force determining unit 19.

  In the electrically assisted bicycle 1 of the present invention, the attachment position of the illuminance measuring means 20 is not particularly limited. For example, some conventional electrically assisted bicycles have a type in which an operation panel is provided on the handle 10, but the illuminance measuring means 20 may be attached to the operation panel. In this case, it is desirable that the illuminance measuring means 20 be directed to the road surface so as not to directly detect the light of a headlamp such as an oncoming vehicle.

  In the electrically assisted bicycle 1 of the present invention, the input torque measuring means 18 for detecting the main driving force, and the auxiliary driving force determining means 19 for determining the auxiliary driving force according to the main driving force detected by the input torque measuring means 18. The illuminance measuring means 20 for measuring the ambient brightness, the illuminance determining means 21 for comparing the illuminance measured by the illuminance measuring means 20 with the determination reference illuminance to determine the magnitude relationship, and the illuminance determining means 21 Depending on the result, the delay control means 22 for delaying the start of output of the auxiliary drive force relative to the start of input of the main drive force, and the battery to the electric motor according to the auxiliary drive force determined by the auxiliary drive force determination means 19 It is only important that the current supply amount control means 23 for controlling the amount of current supplied to the power supply 15 is provided, and there is no particular limitation on the configuration other than these.

  In the electrically assisted bicycle of the present invention, the input torque measuring means, auxiliary driving force determining means, and current supply amount controlling means are not particularly limited, and a torque sensor used in a conventional electrically assisted bicycle can be used. For example, an apparatus used in JP-A-11-11375, JP-A-2001-88770, JP-A-7-309283, etc. may be employed. Also, a known illuminance sensor can be used for the illuminance measuring means, and the same auxiliary driving force determining means as the auxiliary driving force adjusting means can be used. Further, the delay control means is not particularly limited, and those used in conventional electric assist bicycles can be used. For example, JP 2002-264882 A, JP 8-244672 A, and JP 8 H8. The device used in Japanese Patent No. -295285 can be employed.

DESCRIPTION OF SYMBOLS 1 Electric assist bicycle 2 Body frame 3 Head tube 4 Down tube 5 Seat tube 6 Chain stay 7 Seat stay 8 Front fork 9 Front wheel 10 Handle 11 Saddle 12 Rear wheel 13 Pedal 14 Chain 15 Electric motor 16 Crankshaft 17 Battery 18 Input torque measuring means 19 Auxiliary driving force determination means 20 Illuminance measurement means 21 Illuminance determination means 22 Delay control means 23 Current supply amount control means 24 Auxiliary driving force adjustment means

Claims (4)

In an electrically assisted bicycle configured to be driven by a main driving force by human power and an auxiliary driving force by an electric motor,
Input torque measuring means for detecting the main driving force, auxiliary driving force determining means for determining auxiliary driving force according to the main driving force detected by the input torque measuring means, and illuminance measurement for measuring ambient brightness Illuminance determination means for comparing the illuminance measured by the illuminance measurement means with a reference illuminance to determine a magnitude relationship, and at the start of output of the auxiliary driving force according to the result determined by the illuminance determination means A delay control means for delaying the input of the main driving force and a current supply for controlling a current supplied from the battery to the electric motor according to the auxiliary driving force determined by the auxiliary driving force determining means And an amount control means.   When the illuminance detected by the illuminance measuring means is I and the determination reference illuminance is Is, the delay time when the illuminance determining means determines I <Is is when the illuminance determining means determines I ≧ Is The power-assisted bicycle according to claim 1, wherein the power-assisted bicycle is longer than a delay time.   When the illuminance detected by the illuminance measuring means is I and the determination reference illuminance is Is, the delay time when the illuminance determining means determines I <Is is when the illuminance determining means determines I ≧ Is The electrically assisted bicycle according to claim 1, which is smaller than a delay time in.   The electrically assisted bicycle according to any one of claims 1 to 3, further comprising auxiliary driving force adjusting means for adjusting the auxiliary driving force determined by the auxiliary driving force determining means.

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