JP2000103383A - Vehicle with auxiliary power - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a smooth traveling feeling despite of a small auxiliary driving force by delaying the response speed of a motor driving force more as the manual torque becomes larger, when the maximum output torque of the motor driving force is smaller than the maximum detecting value of the preset manual torque detection part. SOLUTION: A duty ratio D of a switching device is appropriately set (S1), an output (a) of a depressing force sensor and an output (b) of a current sensor are read so as to calculate a major driving force TL (S2) and an auxiliary driving fore TM (S3). Secondly, a time constant τ of a value proportional to the read depressing force (a) is operated (S4). A value obtained by dividing the difference between TL and TM by the time constant τ is added to the duty ratio D so as to calculate the duty ratio D1 (S5). The switching device is driven with the duty ratio D1 set to a new duty ratio D (S6). Repeating the processes S2-S6, the motor outputs TM corresponding to TL in proportional to the extent of TM.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vehicle with an auxiliary power, such as an electrically assisted bicycle, which travels with human driving power and electric driving power.

[0002]

2. Description of the Related Art Conventionally, this type of vehicle with auxiliary power, for example, an electric assist bicycle, has been disclosed in Japanese Patent Application Laid-Open No. H8-2446.
No. 72 (B62M23 / 02), delay means for delaying the output of the electric driving force with respect to the manual driving force,
For example, there has been known an integrated circuit which is provided with an integrating circuit to control the vehicle so that smooth running is possible. In this case, an example is described in which the integration constant is constant and the response speed of the electric driving force is delayed in inverse proportion to the traveling speed.

However, with the above-described configuration, when the maximum output torque of the electric drive unit is smaller than the maximum detection value of the human torque detector, the output of the electric drive force is small as shown in FIG. In this case, since the electric driving force is output behind the pedaling force, smooth running can be performed. However, when the detected value of the human driving torque is large, that is, when the output of the electric driving force is large, the detected value of the human driving torque is the same. Even if an attempt is made to output an electric drive force, the maximum output of the electric drive unit is limited, so that a flat output portion is created at a portion where the output of the electric drive force is large, which is helpful when the user is riding. There is a problem in that the driving force has a marginal portion, and the auxiliary driving force feels small on the way, and the ride is very difficult.

Therefore, when traveling on an uphill or the like, the auxiliary driving force cannot be obtained sufficiently and becomes constant at the maximum value, so that it is extremely difficult for the user to travel stably. There was a problem.

[0005]

SUMMARY OF THE INVENTION An object of the present invention is to provide a vehicle with an auxiliary power which can provide a smooth running feeling even with a small auxiliary driving force.

[0006]

SUMMARY OF THE INVENTION The present invention provides a human-powered driving unit that generates a driving force by human power, an electric-powered driving unit that generates a driving force by driving an electric motor, and a human-powered unit that detects the human-powered torque of the human-powered driving unit. A torque detection unit, and a control circuit that operates the electric drive unit based on the detection result of the human-powered torque detection unit, wherein the control circuit is configured to set the electric drive power to be greater than a predetermined maximum detection value of the human-powered torque detection unit. When the maximum output torque is small, the delay means is provided to delay the response speed of the electric driving force as the magnitude of the human-powered torque increases. When the pedaling force is large, that is, when the maximum output value of the electric driving force reaches a limit, control is performed such that the electric driving force is output later than when the pedaling force is small. Constitute the delay means to so that. As a result, when the pedaling force exceeds the maximum output of the electric driving force,
The output limit of the electric driving force can be set to a smooth sine wave so that the electric driving force does not become constant at the output limit.

Further, the delay means comprises an integrator, and changes an integration constant according to the magnitude of the manual torque. The integrator is characterized in that the larger the magnitude of the manual torque, the larger the integration constant.

An electric torque detecting section for detecting a torque of the electric driving section is provided. The electric driving section receives signals from the human torque detecting section and the electric torque detecting section and responds to a difference between these signals. And a signal from the human-powered torque detecting unit is also input to the delay unit. Specifically, the delaying unit is provided between the electric driving unit and the human-powered torque detecting unit. In some cases, the delay means may be provided between the electric drive unit and the electric motor.

With the above configuration, in addition to the effect that smooth running can be performed by the delay means, when driving the electric drive unit, control is performed so that the difference between the manual drive force and the electric drive force is output to the motor. Thus, an auxiliary driving force having a smooth rise and fall can be obtained without a sudden change in torque.

Further, the control circuit is provided with first delay means for increasing the response speed as the manpower torque increases, and second delay means for decreasing the response speed as the manpower torque increases. And selecting means for selecting a delay means in accordance with the maximum detection value of the torque detecting section and the maximum output torque of the electric driving force. Thus, the form of the delay means can be selected, and smooth output of the electric driving force can be performed.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described in detail using an electric assist bicycle as an example.

FIG. 1 is a side view of an electric assist bicycle according to an embodiment, and FIG. 2 is an explanatory diagram of a drive system of the electric assist bicycle.

In these figures, the electric assist bicycle main body 1 includes a driving wheel 2 driven by a human driving unit, ie, a human driving unit 9 and an electric driving unit, ie, an electric driving unit 12.
And a front wheel 3 for determining the traveling direction. Further body 1
Has a frame constituted by a standing pipe 4, an upper pipe 5, and a lower pipe 6, and a saddle 7 is provided at an upper end of the standing pipe 4. A handle 8 for determining the direction of the front wheel 3 is provided above a portion where the upper pipe 5 and the lower pipe 6 intersect.

The human-powered driving means 9 for driving the driving wheels 2 has a pedal 10 like a general bicycle,
The drive force (pedal force) is transmitted to the chain 11 by stepping and rotating the wheel 0, and the drive force is transmitted to the drive wheel 2 via the sprocket 11a, the one-way clutch 11b, and the human-powered torque detecting unit, that is, the pedal force sensor 11c. Transmitted to
The drive wheels 2 are driven.

The pedaling force sensor 11c has a structure in which the rotating shaft of the sprocket 11a and the rotating shaft of the driving wheel 2 are connected by an elastic body, and a magnet displaced by the distortion of the elastic body is detected by a detecting coil. are doing.

Further, the one-way clutch 11b operates the driving wheel 2 more than the rotational speed at which the pedaling force is applied to the driving wheel 2.
When the rotation speed is high, the driving force is prevented from being transmitted from the driving wheels 2 to the chain 11.

The electric driving means 12 for driving the driving wheels 2 in combination with the manual driving means 9 uses a rechargeable battery 13 provided above the driving wheels 2 as a power source and is provided from the battery 13 to a hub of the driving wheels 2. The electric motor 14 is supplied.

In the electric driving means 12, the output from the electric motor 14 is decelerated by a speed reduction mechanism 14a composed of a gear and a belt and transmitted to the driving wheels 2 via a one-way clutch 14b. The one-way clutch 14b does not reversely transmit the driving force from the driving wheels 2 to the motor 14 when the actual rotation speed of the driving wheels 2 is higher than the rotation speed that the motor 14 intends to give to the driving wheels 2. Act like so.

Next, a control circuit of the electric assist bicycle will be described with reference to FIG.

As shown in FIG. 3, the voltage of the battery 13 is connected via a switching element 21 and a power switch 19 to a series circuit of an electric motor 14 and an electric torque detector, that is, an electric motor current sensor (hereinafter referred to as a current sensor) 22. Applied,
The flywheel diode 20 is connected to this series circuit.

Reference numeral 17 denotes a microcomputer including a CPU, a ROM, and a RAM. The microcomputer 17 receives the output from the current sensor 22 and the human-power torque detecting unit, that is, the pedaling force sensor 11c, performs signal processing, and outputs a pulse control signal to the pulse generator 18.

The pulse generator 18 includes a microcomputer 17
The duty ratio of the switching element 21 is controlled based on the duty control signal from.

In this embodiment, a DC brush motor of a permanent excitation type is used for the
A 4 V, 5 Ah NiCad battery is connected to the current sensor 22.
Each uses a shunt resistor of 2.25 milliohms.

The microcomputer 17 turns on and off the switching element 21 at a frequency of 244 Hertz to control the motor 14 by PWM.

In such a configuration, when the user steps on the pedal 10 of the electrically assisted bicycle, the pedaling force is transmitted to the drive wheels 2 via the chain.

Therefore, the microcomputer 17 sets the pedaling force sensor 11c
And the output signal a of the current sensor 22 are amplified by amplification factors A and B, respectively, so that the main driving force TL and the auxiliary driving force T
M is calculated, the duty ratio of the switching element 21 is changed by the difference (TL-TM), and TM and TL are calculated.
The output of the electric motor 14 is controlled so that the ratio of the electric motor 14 becomes constant.

The microcomputer 17 controls the electric motor 14 so that the auxiliary driving force TM is output with a delay with respect to the main driving force TL as shown in FIG. 12, and a second delay means for controlling the electric motor 14 such that the auxiliary driving force TM is output with a delay with respect to the main driving force TL as shown in FIG. The delay of the auxiliary driving force TM with respect to the main driving force TL due to these two delay means changes according to the magnitude of the manual torque of the main driving force TL. The delay is controlled so as to decrease as TL increases, and the second delay means is controlled such that the delay increases as the main driving force TL increases. Regarding this delay means, the delay time with the electric driving force is changed according to the size of the pedaling force sensor 11c. The contents of this control will be described later.

FIGS. 4 and 5 show two types of equivalent circuits representing the control function of the microcomputer 17.

4 and 5, the output a of the treading force sensor 11c is amplified by the amplifier A2 to calculate the main driving force TL, while the output b of the current sensor 22 is amplified by the amplifier A2 to calculate the auxiliary driving force TM. Then, (TL-TM) is calculated by the subtractor F, a pulse having a duty ratio corresponding to the calculated value is output to the pulse generator 18, and the switching element 21 is turned on / off according to the pulse ratio to turn on the electric motor 14. Drive.

The first and second delay circuits (integrators) P whose delay time (time constant) changes substantially in proportion to the treading force a output from the treading force sensor 11c include an amplifier in FIG. It is inserted between A1 and the subtractor F, and is inserted between the subtractor F and the pulse generator 18 in FIG. The pedaling force a output from the pedaling force sensor 11c is input to the delay circuit P in both FIGS. Therefore,
In each of the equivalent circuits shown in FIGS.
The output of the auxiliary driving circuit TM is delayed substantially in proportion to the magnitude of the main driving force TF. And
The first and second delay circuits P are selected according to the maximum output of the electric motor 14 when the electric motor 14 is selected.

An example in which the operation when the first delay circuit is selected is executed by a program built in the microcomputer 17 will be described with reference to the flowchart of FIG.

First, in step S1, the duty ratio D of the switching element 21 is appropriately set, the output a of the pedaling force sensor 11c and the output b of the current sensor 22 are read, and the main driving force TL and the auxiliary driving force TM are calculated. (Steps S2, S3).

Next, a value proportional to the read pedal effort a, that is, a time constant τ is calculated (step S4). The calculation of this time constant is represented by an equation representing the graph shown in FIG.
It is calculated by a · K. Then, a value obtained by dividing the difference between the main driving force TL and the auxiliary driving force TM by the time constant τ is added to the duty ratio D set in step S1 to calculate the duty ratio D1 (step S5).

The duty ratio D1 is set as a new duty ratio D (step S7), and the switching element 21 is driven. By repeating the steps S2 to S6, the electric motor 14 outputs the auxiliary driving force TM corresponding to the main driving force TL in proportion to the magnitude of the auxiliary driving force TM.

As described above, by performing control based on the result calculated by the mathematical expression shown in step S4, as shown in FIG. 8, when the pedaling force is large, there is almost no delay time, and the auxiliary driving force is output following. You. However, as the pedaling force decreases, the delay time of the output of the electric driving force with respect to the pedaling force increases.

This state will be specifically described.
As shown in FIG. 8B, when little auxiliary driving force is required, such as on a flat ground, the operation of the first delay circuit causes the electric driving force to be output behind the treading force, so that the driving feeling is improved. It has the effect of being very smooth. In addition, as shown in FIG. 8A, when the vehicle is started or traveling on an uphill, the pedaling force is extremely large, and a large auxiliary driving force is required. In such a case, since the first delay circuit is controlled such that the output time of the electric driving force with respect to the treading force is hardly delayed, the electric driving force is output following the treading force with almost no delay. When a large auxiliary driving force is required, the auxiliary driving force can be obtained without delay.

Next, the operation when the second delay circuit is selected will be described with reference to the flowchart of FIG. This flowchart is almost the same as the case where the first delay circuit is selected, and differs only in the step S4. Therefore, only this part will be described.

The main driving force TL and the auxiliary driving force TM that have been read and amplified are equal to the duty ratio D of the switching element 21.
In order to determine the value, a value proportional to the read pedal force a, that is, a time constant τ is calculated in step S4. Regarding the calculation of this time constant, an equation representing the graph shown in FIG.
It is calculated by K + b. That is, the constant of the integrator increases as the main driving force TL increases, that is, the main driving force T
As L becomes larger, auxiliary driving force TM becomes main driving force T
It is set so as to be output with a delay of L.

Then, similarly to the case where the first delay circuit is selected, by repeating the steps S2 to S6, the electric motor 14 generates the auxiliary driving force TM corresponding to the main driving force TL and the auxiliary driving force TM Will be output in proportion to the size of.

As described above, by performing control based on the result calculated by the mathematical expression shown in step S4, as shown in FIG. 12, when the pedaling force is large, that is, the electric driving force TM
In the case of the maximum output, the output of the electric driving force TM is greatly delayed with respect to the pedaling force, so that the flat portion of the output, which peaks at the maximum output, can be approximated to a sine wave, and a smooth running can be obtained.

The graph shown in FIG. 9 shows the case where the first delay circuit is used when the maximum output of the electric driving force is smaller than the maximum detection value of the human-powered torque detector, and the same electric driving force as the human-powered torque. The output value becomes flat at the maximum output portion of the electric driving force TM, and the auxiliary driving force is reduced when a large auxiliary driving force is required. Since it becomes constant, the user feels the lack of the auxiliary driving force.

In order to prevent such a situation, when the motor 14 is incorporated, if the maximum output value of the electric driving force TM is smaller than the maximum detection value of the human-powered torque detection unit 11c, the second
Is selected, otherwise, the first delay circuit is selected. By doing so, no matter what output the motor 14 has, it is only necessary to select the first or second delay circuit when selecting the motor 14, and only one program for other control needs to be developed. It is only necessary to select a delay circuit by selecting a port of the microcomputer.

Therefore, when the first delay circuit is selected, when the auxiliary driving force is not required so much on a level ground,
By the function of the delay circuit, the electric driving force is output with the delay of the pedaling force, and the feeling of traveling becomes very smooth,
In addition, when traveling on an uphill or at the time of starting, the delay circuit works so that the output time of the electric driving force with respect to the pedaling force is controlled so that there is almost no delay time. The electric driving force is output.

When selecting the second delay circuit,
This is a case where the maximum output value of the electric driving force is smaller than the maximum output value of the human-powered torque detection unit 11c. In such a case, when the first delay circuit is selected, the situation shown in FIG. By selecting the second delay circuit, as shown in FIG. 12, it is possible to smooth out the vicinity of the maximum value of the electric driving force and output a signal close to a sine wave, thereby obtaining a smooth auxiliary driving force.

[0045]

According to the present invention, there is provided a human-powered driving unit for generating a driving force by human power, an electric-powered driving unit for generating a driving force by driving an electric motor, and a human-powered torque detecting unit for detecting the human-powered torque of the human-powered driving unit. A control circuit that operates an electric drive unit based on a detection result of the human-powered torque detection unit, wherein the control circuit is configured to output a maximum output torque of the electric drive force more than a predetermined maximum detection value of the human-powered torque detection unit. When the motor driving force is small, a delay means is provided to reduce the response speed of the electric driving force as the magnitude of the human driving torque increases, so that the maximum output of the electric driving force does not maintain a constant value, and The output can be output in a waveform close to a sine wave, and the auxiliary driving force can be smoothed.

Further, the delay means is constituted by an integrator, and changes the integration constant according to the magnitude of the human-powered torque. Is increased, so that the above effect can be obtained with a simple configuration.

Further, an electric torque detecting section for detecting a torque of the electric driving section is provided, and the electric driving section receives signals of the human torque detecting section and the electric torque detecting section and responds to a difference between these signals. The driving signal is output, and the signal from the human-powered torque detection unit is also input to the delay unit.In addition to the effect that the traveling can be smoothly performed by the delay unit, when the electric drive unit is driven, Since the control is performed so as to output the difference between the manual driving force and the electric driving force to the electric motor, the control is always performed based on the actual duty difference,
There is an effect that an auxiliary driving force having a smooth rise and fall can be obtained without a sudden change in torque.

Further, the control circuit comprises: first delay means for increasing a response speed as the human torque increases;
A second delay unit that reduces a response speed as the manpower torque increases; and a delay unit according to a maximum detection value of the manpower torque detection unit and a maximum output torque of the electric driving force. Since the selection means for selecting is provided, the delay circuit can be selected according to the magnitude of the maximum output of the electric driving force at the time of selecting the electric motor, so that there is an effect that the configuration can be simplified.

[0049]

[Brief description of the drawings]

[0050]

FIG. 1 is a side view of an electric assist bicycle showing an embodiment of the present invention.

[0051]

FIG. 2 is a configuration explanatory view showing a drive system of the electric assist bicycle of FIG. 1;

[0052]

FIG. 3 is a control circuit of the embodiment.

[0053]

FIG. 4 is a circuit diagram showing an example of an equivalent circuit of the control circuit according to the embodiment.

[0054]

FIG. 5 is a circuit diagram showing another example of an equivalent circuit of the control circuit of the embodiment.

[0055]

FIG. 6 is a flowchart showing an operation of the embodiment using the first delay circuit.

[0056]

FIG. 7 is a graph showing a change in a constant of an integrator with respect to a pedaling force of an embodiment using a first delay circuit.

[0057]

FIG. 8A shows an operation when a large torque is generated in the embodiment using the first delay circuit, and FIG.
7 is a graph showing an operation when a small torque is generated in the embodiment using the delay circuit of FIG.

[0058]

FIG. 9 is a graph showing an operation when the first delay circuit is used when the maximum output of the electric driving force is smaller than the maximum detection value of the manual torque detection unit.

[0059]

FIG. 10 is a flowchart showing an operation of the embodiment using the second delay circuit.

[0060]

FIG. 11 is a graph showing a change in a constant of an integrator with respect to a pedaling force in an embodiment using a second delay circuit.

[0061]

FIG. 12 is a graph showing an operation of the embodiment using the second delay circuit.

[0062]

[Explanation of symbols]

 9 Human-powered drive unit 14 Electric motor 12 Electric-powered drive unit 11c Human-powered torque detector 17 Control circuit P Integrator (delay means) 22 Current sensor (Electric torque detector)

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Masanori Kamei 2-5-2-5 Keihanhondori, Moriguchi-shi, Osaka Sanyo Electric Co., Ltd. (72) Inventor Hiroaki Sagara 2-5-2 Keihanhondori, Moriguchi-shi, Osaka No. 5 Sanyo Electric Co., Ltd. (72) Inventor Toshihiro Matsumoto 2-5-5-Keihanhondori, Moriguchi-shi, Osaka Pref. 5-5, Sanyo Electric Co., Ltd.

Claims (7)

[Claims] A human-powered driving unit that generates a driving force by driving a motor; an electric-powered driving unit that generates a driving force by driving an electric motor; a human-powered torque detecting unit that detects a human-powered torque of the human-powered driving unit; A control circuit that operates the electric drive unit based on the detection result of the detection unit, wherein the control circuit is configured such that when the maximum output torque of the electric drive force is smaller than a predetermined maximum detection value of the human torque detection unit. A vehicle with auxiliary power, characterized by comprising delay means for reducing the response speed of the electric driving force as the magnitude of the human torque increases. 2. The vehicle with auxiliary power according to claim 1, wherein said delay means comprises an integrator, and changes an integration constant in accordance with the magnitude of said manual torque. 3. The vehicle with auxiliary power according to claim 2, wherein the integrator increases the integration constant as the magnitude of the manual torque increases. 4. An electric torque detecting section for detecting a torque of the electric driving section, wherein the electric driving section inputs signals of the human torque detecting section and the electric torque detecting section and calculates a difference between these signals. 2. The vehicle with auxiliary power according to claim 1, wherein a driving signal is output in response to the driving signal, and a signal from a human-powered torque detector is also input to the delay unit. 5. The vehicle with auxiliary power according to claim 4, wherein the delay unit is provided between the electric drive unit and the manual torque detection unit. 6. The vehicle with auxiliary power according to claim 4, wherein said delay means is provided between an electric drive section and an electric motor. 7. The control circuit according to claim 1, wherein the response speed increases as the human-powered torque increases.
A second delay unit that reduces a response speed as the human-powered torque increases, and selects a delay unit according to a maximum detection value of the torque detection unit and a maximum output torque of the electric driving force. 2. The vehicle with auxiliary power according to claim 1, further comprising a selection unit that performs the selection.