JP2000072080A - Auxiliary power control method of motor-assisted bicycle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an auxiliary power control method of a motor-assisted bicycle which is capable of suppressing the current consumption to be low and increasing the cruising distance per one charge of a battery. SOLUTION: In a motor-assisted bicycle which detects the stepping force, supplying the assist current according to the magnitude of the stepping force to an electric motor, and travels under the assist by the power generated by the electric motor, when the condition where the stepping force is not more than a first threshold (the assist-cut stepping force) continues for a specified time Δt, the supply of the assist current is stopped or the assist current is set to be lower than the regular set value, and when the stepping force exceeds a second threshold (assist re-starting stepping force) higher than the first threshold, the supply of the regular assist current is controlled so as to be re-started.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an auxiliary power control method for an electric assist bicycle.

[0002]

2. Description of the Related Art An electric assisted bicycle has been developed which detects a treading force, supplies an assist current corresponding to the magnitude of the treading force to an electric motor, and runs with assistance by the assisting power generated by the electric motor. It has been put to practical use.

In such an electric assist bicycle, the assist current supplied from the battery to the electric motor is set to a value such that the electric motor generates an auxiliary power substantially equal to the stepping force of the occupant.

[0004]

However, in the conventional control of the auxiliary power of the electric assisted bicycle, even when the assist by the auxiliary power is unnecessary or when the assist is necessary or small, it is specified. Since the assist current was supplied to the electric motor to generate the predetermined auxiliary power,
There is a problem that wasteful current consumption occurs and the cruising distance per charge of the battery cannot be extended.

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and an object thereof is to provide an auxiliary power for an electric assisted bicycle capable of extending the cruising distance per charge of a battery while keeping current consumption low. It is to provide a control method.

[0006]

According to a first aspect of the present invention, there is provided an electric vehicle, comprising: detecting a pedaling force and supplying an assist current corresponding to the magnitude of the pedaling force to the electric motor; When the state where the pedaling force is equal to or less than the first threshold continues for a predetermined period of time in the electric assisted bicycle that runs with the assist by the generated assist power, the supply of the assist current is stopped or the assist current is set to be lower than the regular set value. , In which state the pedaling force is higher than the first threshold value.
When the threshold value is exceeded, the supply of the normal assist current is restarted.

According to a second aspect of the present invention, the electric vehicle drives the electric motor by detecting the treading force and supplying an assist current corresponding to the magnitude of the treading force to the electric motor. In electric assist bicycles, a regular assist current is supplied at the portion where the tread force rises from the bottom dead center to the top dead center in a sinusoidally changing tread force waveform, and the tread force falls from the top dead center to the bottom dead center. The unit is characterized in that the supply of the assist current is stopped or the assist current is set lower than a normal set value.

Therefore, according to the first aspect of the present invention, when the pedaling force is high and the assist by the auxiliary power is required, such as when starting or climbing a slope, a regular assist current is supplied to the electric motor. While necessary and sufficient regular auxiliary power can be obtained, the assist current supply is stopped or the assist current is reduced when the pedaling force is low or the assist by the auxiliary power is unnecessary or small, such as when traveling on a flat road. Since the current consumption can be kept low by setting it lower than the set value,
Reasonable current consumption is made possible, and the current consumption can be reduced as a whole, and as a result, the cruising distance of the battery-assisted bicycle per charge of the battery can be extended.

According to the second aspect of the present invention, a normal assist current is supplied to the electric motor in the stepping force increasing portion in which the occupant applies power during a cycle of riding the electric assist bicycle, and the electric motor is supplied with a necessary and sufficient normal electric current. Although the assist power of this type can be obtained, the supply of assist current can be stopped or the assist current can be made lower than the regular set value in the stepping force lowering part where the power is released, so that the current consumption can be kept low. It is possible to consume and reduce the current consumption as a whole,
As a result, the cruising distance of the battery-assisted bicycle per charge of the battery can be increased.

[0010]

Embodiments of the present invention will be described below with reference to the accompanying drawings.

<First Embodiment> First, a schematic configuration of an electric assist vehicle 1 to which the present invention is applied will be described with reference to FIG.

FIG. 1 is a side view of a battery-assisted bicycle 1. The battery-assisted bicycle 1 has a head pipe 2 at an upper front part of a vehicle body. It is freely inserted. A handle 4 is mounted on the upper end of the handle stem 3 with a forward offset, and a front fork 5 is attached to a lower end of the handle stem 3. A front wheel 6 is attached to a lower end of the front fork 5. It is rotatably supported.

A down tube 7 extends obliquely downward from the head pipe 2 toward the rear of the vehicle body.
A seat tube 8 is erected diagonally upward from the rear end of the down tube 7 extending substantially horizontally toward the rear of the vehicle body. A retractable saddle 10 is supported at the upper end of a seat post 9 fitted and held in the seat tube 8 so as to be vertically movable so as to be adjustable in height.

On the other hand, a power unit 11 is disposed substantially below the center of the vehicle body. This power unit 11
A drive system based on human power (pedal force) and an auxiliary power system based on the electric motor 12 are arranged side by side, and output by combining the human power (pedal force) and the auxiliary power of the occupant. It is rotatably supported. Cranks 14 are mounted on the left and right sides of the crankshaft 13, and a pedal 15 is rotatably supported at an end of each crank 14. The periphery of the connection between the down tube 7 and the seat tube 8 and a part of the power unit 11 are covered with a resin cover 16. Further, the power unit 11 is provided with a controller 17 for controlling the output (auxiliary power) of the electric motor 12 according to the magnitude of human power (pedal force of the occupant input to the pedal 15). Here, the output (auxiliary power) of the electric motor 17 is controlled by controlling the assist current supplied to the electric motor 17.

A pair of left and right chain stays 18 extend substantially horizontally to the rear of the power unit 11. The rear end of the chain stay 18 and the upper end of the seat tube 8 form a pair of left and right seats. They are connected by stays 19. A rear wheel 20 is rotatably supported at a connection between the rear end of the chain stay 18 and the seat stay 8, and a part of the rear wheel 20 is a rear fender 21.
Covered by

Further, a wheel sprocket 22 is connected to the rear wheel 20, and an endless chain 23 is wound between the wheel sprocket 22 and a drive sprocket (not shown) provided in the power unit 11. Is equipped.

On the other hand, in the battery-assisted bicycle 1 according to the present embodiment, a battery 24 is detachably mounted in a space below the saddle 10 and surrounded by the seat tube 8 and the rear fender 21. I have. The battery 24 is attached and detached along the seat tube 8 with the saddle 10 flipped up to avoid interference with the saddle 10.

Next, a power transmission path in the power unit 11 will be described with reference to a block diagram shown in FIG.

When the occupant steps on the pedal 15, the pedaling force (manual force) is transmitted to the resultant shaft 26 via the crankshaft 13 and the one-way clutch 25, and the pedaling force and the vehicle speed are not shown on the transmission path. Are respectively detected by the pedaling force sensor and the vehicle speed sensor, and their detection signals are input to the controller 17.

Then, the controller 17 calculates a predetermined auxiliary power (assist force) based on various signals input thereto and various data stored in the memory 27, and outputs a control signal (output instruction) corresponding to the auxiliary power. Signal) to the electric motor 12.

The assisting force generated by the electric motor 12 is transmitted to the resultant shaft 26 via the speed reducer 28 and the one-way clutch 29, and the one-way clutch 30 and the speed change mechanism 31
And transmitted to the rear wheel 20 via the chain 23 shown in FIG.

Next, an auxiliary power control method which is the gist of the present invention will be described with reference to FIGS.

In the battery-assisted bicycle 1 according to the present embodiment, the controller 17 switches the battery 24 from the battery 24 to the electric motor 12 when the state in which the pedal effort is equal to or less than a first threshold value (assist cut value determination value) continues for a predetermined time. If the supply of the assist current is stopped or the assist current is set lower than the normal set value, and the pedaling force exceeds a second threshold value (assist restart determination value) higher than the first threshold value in this state, the normal assist current is set. Is controlled to restart the supply of water.

Here, the auxiliary power control method will be specifically described with reference to FIGS. FIG. 3 is a flowchart showing a control procedure of the auxiliary power, and FIG. 4 is a view showing a temporal change of the pedaling force, the auxiliary power, and the resultant force (= pedaling power + auxiliary power).

When the occupant starts pedaling the pedal 15 of the electric assist bicycle 1 at time t ₀ shown in FIG. 4, the pedaling force changes in a sinusoidal manner as shown in FIG. Is generated at time t ₁ (> t ₀ ), and this auxiliary power changes in a sinusoidal manner like the pedaling force as shown in FIG. 4B. Therefore, the electric assisted bicycle 1 is driven and driven by the resultant force of the pedaling force and the auxiliary power, and this resultant force also changes in a sinusoidal manner like the pedaling force and the auxiliary power as shown in FIG.

Thus, in the main loop of the motor control program built in the controller 17, as shown in FIG. 3, it is determined whether or not the current assist cut state (the state where the assist by the normal auxiliary power is interrupted). Is determined (step S1). At the beginning of traveling, the assist state (the state in which assist by the regular auxiliary power is performed) is maintained, so the determination result in step S1 is NO, and the process proceeds to step S2.
It is determined whether or not the current pedaling force is equal to or less than the assist cut determination value (first threshold value) shown in FIG.

If the current treading force is larger than the assist cut determination value, a normal assist current is supplied from the battery 24 to continue the normal assist with the normal assist power (step S3), and the current treading force is reduced to the assist cut. If the state (low pedaling force state) does not continue for the predetermined determination time Δt or longer even if it is equal to or less than the determination value, the normal assist state is similarly continued (steps S2 → S4 → S3).

On the other hand, as shown from time t _{2 to} t ₃ in FIG. 4A, when the state where the current pedaling force is equal to or less than the assist determination value (low pedaling force state) continues for a predetermined determination time Δt or more,
Assist cut is executed (steps S2 → S4 → S
5) In the assist cut state, the supply of the assist current from the battery 24 to the electric motor 12 is stopped and the auxiliary power is cut off, or the auxiliary power is set to a normal level as shown by a broken line in FIG. Is set lower than the value of.
In FIG. 4C, the broken line indicates the resultant force when the assist current is set lower than the normal value in the assist cut state, and the resultant force when the assist power is completely cut off is shown in FIG. 4A. It becomes equal to the pedaling force.

In the assist cut state, whether the current pedaling force is equal to or greater than the assist restart determination value (second threshold value) set to a value higher than the assist cut determination value shown in FIG. Is determined (step S6),
While the pedaling force is less than the assist restart determination value (time t in FIG. 4)
₃ ~t ₄₎ Assist-cut state is continued (step S7), and the normal assist is resumed at the time the depression force is equal to or higher than the assist restart determination value (time t ₄ in FIG. 4) (step S8).

As described above, in the auxiliary power control method according to the present embodiment, when the pedaling force is high and the assist by the auxiliary power is required, such as when starting or climbing a hill, a regular assist current is supplied to the electric motor. 12 to supply necessary and sufficient regular auxiliary power, but when the pedaling force is low and the assist by the auxiliary power is unnecessary or small, such as when driving on a flat road, the supply of the assist current is stopped or Since the current consumption can be reduced by lowering the assist current below the regular set value, reasonable current consumption is possible, and the current consumption can be reduced as a whole,
As a result, the cruising distance of the battery-assisted bicycle 1 per charge of the battery 24 can be extended.

Second Embodiment Next, a second embodiment of the present invention will be described with reference to FIGS.

The configuration of the electric assist bicycle to which the auxiliary power control method according to the present embodiment is applied is the same as that of the electric assist bicycle 1 according to the first embodiment shown in FIG. And illustration thereof will be omitted, and in the following description, the same elements will be described using the same reference numerals as those shown in FIG.

The auxiliary power control method according to the present embodiment
A normal assist current is supplied in the stepping force rising portion from the bottom dead center to the top dead center of the sinusoidally changing treading force waveform, and in the stepping force descending portion from the top dead center to the bottom dead center. The supply of the assist current is stopped or the assist current is set lower than a regular set value.

Here, the auxiliary power control method will be specifically described with reference to FIGS. FIG. 5 is a flowchart showing a control procedure of the auxiliary power, and FIG. 5 is a diagram showing a temporal change of the pedaling force, the auxiliary power, and the resultant force (= the pedaling power + the auxiliary power).

When the occupant starts pedaling the pedal 15 of the electric assist bicycle 1, the pedaling force changes sinusoidally as shown in FIG. 6 (a). In the control method according to the present embodiment, the sinusoidal force is applied. depression force increase of from bottom dead center to top dead center of the varying pedaling force waveform (time t ₁ ~t ₂ in FIG. 6, t ₃ ~t
_4, and supplies the normal assist current to the electric motor 12 in ...), pedal force lowering portion up to the bottom dead center beyond the upper dead point (time t ₂ ~t ₃ in FIG. 6, t ₄ ~t ₅ , ...), the supply of the assist current is stopped or the assist current is set lower than the normal set value.

Therefore, as shown in FIG. 6 (b), a regular auxiliary power is generated in the portion where the treading force is increased (time t _{1 to} t ₂ , t _{3 to} t ₄ ,...), As shown in FIG. 6 (c). Resultant force (= pedal force +
The electric assist bicycle 1 is driven by the assist power and travels.

On the other hand, as shown in FIG. 6B, the supply of the assist current from the battery 24 to the electric motor 12 is stopped in the stepping force decreasing portion (time t _{2 to} t ₃ , t _{4 to} t ₅ ,...). Thus, the auxiliary power is cut or the auxiliary power is set lower than the normal value as shown by the broken line. FIG.
In (c), the broken line indicates the resultant force when the assist current is set lower than the normal value, and the resultant force when the auxiliary power is completely cut is equal to the pedaling force shown in FIG.

Thus, in the main loop of the motor control program built in the controller 17, the processing shown in FIG. 5 is performed.

That is, the current pedaling force is detected (step S
11) It is determined whether or not the detected current treading force is equal to or greater than the treading force detected last time and whether the state has been continued for a certain period of time (step S12). Stepping force increasing portion in pedal effort is pedaling force waveform if the determination result in step S12 is YES (the time of FIG. _{6 t 1 ~t 2, t 3} ~t 4, ...)
Therefore, a normal assist current is supplied to the electric motor 12 (step S13) to generate a normal auxiliary power (see FIG. 6B), and the current pedaling force is stored for the next comparison ( Step S14).

On the other hand, if the decision result in the step S12 is NO,
Is determined, it is determined whether or not the state in which the current treading force is smaller than the previous treading force has continued for a predetermined time (step S
15) If the determination result is NO, the current state is maintained (step S16), and if the determination result is YES, the treading force increases in the treading force waveform (time t in FIG. 6).
₂ ~t _3, t ₄ ~t ₅ battery 24 to be in, ...)
, The supply of the assist current to the electric motor 12 is stopped and the auxiliary power is cut off, or the auxiliary power is set lower than the normal value as shown by the broken line in FIG. 6B (step S17). .

According to the auxiliary power control method according to the present embodiment, a normal assist current is applied to the electric motor 12 in the stepping force increasing portion in which the occupant applies power during the cycle of riding the electric assist bicycle 1. In the step-down section where the power is released, the assist current is stopped or the assist current is reduced below the regular set value to reduce the current consumption. Therefore, the current consumption can be reduced rationally, the current consumption can be reduced as a whole, and as a result, the cruising distance of the battery-assisted bicycle 1 per charge of the battery 24 can be extended.

[0042]

As is apparent from the above description, claim 1
According to the described invention, when the pedaling force is high and the assist by the auxiliary power is required, such as when starting or climbing a hill, a normal assist current is supplied to the electric motor so that the necessary and sufficient normal auxiliary power is provided. On the other hand, if the pedaling force is low and the assist by the auxiliary power is unnecessary or small, such as when driving on a flat road, the supply of the assist current is stopped or the assist current is reduced below the regular set value and consumed. Since the current can be kept low, reasonable current consumption can be achieved, and the current consumption can be kept low as a whole. As a result, the range of the battery-assisted bicycle per charge of the battery can be extended. The effect that it can be obtained is obtained.

According to the second aspect of the present invention, a normal assist current is supplied to the electric motor in the stepping force increasing portion in which the occupant applies force in a cycle of riding the electric assist bicycle, and the electric motor is supplied with a necessary and sufficient normal electric current. Although the assist power of this type can be obtained, the supply of assist current can be stopped or the assist current can be made lower than the regular set value in the stepping force lowering part where the power is released, so that the current consumption can be kept low. It is possible to consume and reduce the current consumption as a whole,
As a result, an effect is obtained that the cruising distance of the battery-assisted bicycle per charge of the battery can be extended.

[Brief description of the drawings]

FIG. 1 is a side view of an electric assist bicycle.

FIG. 2 is a block diagram showing a power transmission path in a power unit of the electrically assisted bicycle.

FIG. 3 is a flowchart showing an auxiliary power control procedure according to the first embodiment of the present invention.

FIG. 4 is a diagram showing changes over time of the pedaling force, the auxiliary power, and the resultant force (= pedaling power + auxiliary power) when the auxiliary power control method according to the first embodiment of the present invention is used.

FIG. 5 is a flowchart showing an auxiliary power control procedure according to Embodiment 2 of the present invention.

FIG. 6 is a diagram showing changes over time of the pedaling force, the auxiliary power, and the resultant force (= pedaling power + auxiliary power) when the auxiliary power control method according to Embodiment 2 of the present invention is used.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Electric assist bicycle 11 Power unit 12 Electric motor 17 Controller 24 Battery

Claims (2)

[Claims] 1. An electric assisted bicycle that detects a treading force, supplies an assist current corresponding to the magnitude of the treading force to an electric motor, and travels with assist by the assisting power generated by the electric motor. When the state equal to or less than the threshold value of 1 is continued for a predetermined time, the supply of the assist current is stopped or the assist current is set to be lower than the normal set value, and in this state, the second threshold value in which the pedaling force is higher than the first threshold value An auxiliary power control method for an electric assist bicycle, characterized in that supply of a regular assist current is restarted when the power exceeds the limit. 2. An electric assist bicycle that detects a treading force, supplies an assist current corresponding to the magnitude of the treading force to an electric motor, and travels with assistance by the assisting power generated by the electric motor. A regular assist current is supplied in the stepping force rising portion from the bottom dead center to the top dead center of the changing treading force waveform, and an assist current is supplied in the stepping force falling portion from the top dead center to the bottom dead center. An auxiliary power control method for an electrically assisted bicycle, wherein the suspension or the assist current is set lower than a normal set value.