JP2002356191A - Power-assisted bicycle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To lengthen the power-assisted travel distance without impairing convenience. SOLUTION: This power-assisted bicycle is provided with a human-power driving system driven by human power and a motor driving part as a motor driving system arranged in parallel, and provided with a micro computer as a control means for controlling output to a motor according to the human-power torque Tc of the human-power driving system, and controlling the response speed of the output of the motor driving system in increasing the output motor torque Tm and the response speed of the output of the motor driving system in decreasing the output. Thus, the response speed in increasing the motor torque can be varied so as to vary the apparent assist ratio according to the status of a traveling road.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electric assist bicycle for assisting a human drive system with an electric drive system.

[0002]

2. Description of the Related Art As a conventional electric assist bicycle, a human-powered driving system driven by a pedaling force of a person who steps on a pedal and an electric driving system driven by a motor powered by a battery are provided in parallel, and human-powered torque by the pedaling force is provided. And the motor torque is detected, and the assist mode in which the assist ratio between the human power torque and the motor torque by the pedaling force becomes 1: 1 and the assist ratio is reduced (for example, the motor torque is set to 0.4 with respect to the human torque 1). A device that switches between an energy saving auto mode and a manual switch is known.

When a relatively large assist is required by a motor such as a hill, this assisted bicycle can be switched to a free running mode by a manual switch to reduce manpower torque and run comfortably. By switching to the energy-saving auto mode with a manual switch when the vehicle can travel even if it is small, the travelable distance can be extended with the assistance of the electric drive system.

[0004] However, the driver has to switch the switch each time according to the condition of the traveling road, which is troublesome and inconvenient.

[0005] Further, since the assist ratio is constant irrespective of the traveling speed, when the vehicle is traveling at a low speed, the assistance by the motor is insufficient and the vehicle cannot travel comfortably. There was too much assistance and the power consumption was high.

[0006]

SUMMARY OF THE INVENTION An object of the present invention is to provide an electrically assisted bicycle that can comfortably and extend the mileage in which motor assist can be performed without impairing usability.

[0007]

Means for solving the above problem is to provide a man-powered driving system and an electric driving system which are driven by human power in parallel, and to output the electric driving system according to the load of the human driving system. The electric assist bicycle to be controlled is provided with control means capable of controlling a response speed of the electric drive system output when the output of the electric drive system increases and a response speed of the electric drive system output when the output decreases. .

In the above configuration, the response speed of the output of the electric drive system when the output of the electric drive system increases is slower than the response speed of the output of the electric drive system when the output decreases.

The control means makes the energy-saving operation in which the response speed at the time of output increase is slower than the response speed at the time of decrease, and the response speed at the time of increase and the response speed at the time of decrease under predetermined conditions substantially equal. The control in the energy saving auto mode for switching between the free running mode and the free running mode is possible.

The control means controls the energy saving operation when the load is equal to or less than a first predetermined load, and switches from the energy saving operation to a free running operation when the load exceeds the first predetermined load. It is.

Further, the control means switches from the free running operation to the energy saving operation when the load becomes equal to or less than a second predetermined load.

[0012] Further, the control means switches from the free running operation to the energy saving operation when the state in which the load is equal to or less than the second predetermined load has continued for a predetermined time.

Preferably, the second predetermined load is smaller than the first predetermined load.

Further, the control means, when switching from the free running operation to the energy saving operation, gradually lowers the response speed when the output of the electric drive system is increased from the response speed in the free running operation, thereby reducing the energy saving operation. It is to switch to the response speed of.

Further, there is provided a free running mode in which the response speed when the output of the electric drive system is increased and the response speed when the output is decreased are always almost the same, and means for switching between the free running mode and the energy saving auto mode are provided. Things.

[0016]

1 to 5 show an electric power assisted bicycle according to an embodiment of the present invention, which will be described below with reference to these drawings.

FIG. 1 is an overall view of a rear wheel drive type electric assist bicycle.

A front wheel 3, a rear wheel 4, a handle 5 and a saddle 6 are attached to a frame 2 of the electric bicycle body 1.
The front wheel 3 is steered by a steering wheel 5.

Reference numeral 7 denotes a human-powered driving unit as a human-powered driving system, which is provided with a pedal 8 and a chain 9.
, The rear wheel 4 is rotated via the chain 9. In this example, the chain 9 is a transmission member of human power.
The invention is not limited to this, and a belt, a rotating shaft, or the like may be used instead of the chain 9.

An electric drive unit 10 as an electric drive system is provided at a portion of the rotating shaft of the rear wheel 4. The electric drive unit 10 incorporates a motor 19 described later, and drives the motor 19 to rotate the rear wheel 4 together with the manual drive unit 7 when electric drive is required.

Brake levers 11 are attached to the left and right ends of a steering wheel 5 for steering the front wheels 3, respectively.
And the brake devices 12, 13 and the wires 14, 1 for the rear wheel 4.
5, respectively. This wire 14,
A brake switch (not shown) is provided in the middle of 15, and the mechanism is such that the power supply to the motor 19 is stopped when the brake lever 11 is operated.

A car 16 is provided in front of the handle 5, and a battery 17 serving as a power source for a motor 19 is detachably mounted under the car 16. The power supply voltage of the battery unit 17 is approximately 24 volts. Note that the battery unit 17 may be provided in another place of the frame 2.

Next, the configuration of the control device 18 of the electric drive unit 10 will be described with reference to FIG.

The control device 18 includes a control circuit 30 and a motor 19
And a battery unit 17 as a power source. The battery unit 17 supplies power to the microcomputer 21 via the step-down circuit 20 and also supplies power to the motor drive circuit 22.

Reference numeral 23 denotes a human-powered torque sensor built in the electric drive unit 10, which detects a human-powered torque Tc due to a treading force as a load of the human-powered drive unit 7 and outputs the detected torque to the microcomputer 21.

A motor torque sensor 24 detects the torque Tm of the motor 19, and outputs the detected motor torque Tm to the microcomputer 21.

The microcomputer 21 has a human-powered torque sensor 23.
The motor drive circuit 22 is controlled based on the output from the motor and the output from the motor torque sensor 24. Motor drive circuit 2
Reference numeral 2 controls a drive current supplied to the motor 19 by pulse modulation (PWM).

The motor 19 uses a DC brushless motor, and the rotational position of the motor 19 is sequentially output to the microcomputer 21 by the Hall IC 25, and the energization is switched based on the signal to drive the microcomputer.

The electric assist bicycle 1 is controlled in a free running mode in which the assist ratio is 1: 1.
The control in the energy-saving auto mode based on the flowchart of FIG.

Here, in the energy saving auto mode, the response speed when the output of the motor 19 is increased is reduced to reduce the motor torque T.
The energy saving operation in which m follows the manual torque Tc with a delay, and the response speed when the motor output increases also increases the motor torque T
m is a free running operation that quickly follows the human torque Tc.

Next, the operation of the energy saving auto mode will be described with reference to the flowchart of FIG.

In step S1, an initial value a1 during energy saving operation (here, a1 = 0.2) is substituted for a response speed adjustment value a as a coefficient for changing the response speed. In step S2, the human torque Tc is detected by the human torque sensor 23, and in step S3, the motor torque Tm is detected by the motor torque sensor 24.

In step S4, it is determined whether the human-powered torque Tc is greater than the first predetermined torque T1, and if it is, in step S5, the response speed adjustment value a is set to the maximum value a2 during free running (here, a2 = 1). .0), the process proceeds to step S6, and if T1 or less, the process proceeds to step S6 with the response speed adjustment value a unchanged.

In step S6, it is determined whether or not human torque Tc is smaller than second predetermined torque T2.
If it is smaller than 2, counting of the timer of the microcomputer 21 is started in step S7, and if it is not less than T2, the timer is initialized and the process proceeds to step S12 described later.

In step S9, it is determined whether or not the time of the timer has passed the predetermined time t1, that is, whether or not the state where the human-powered torque Tc is smaller than the second predetermined torque T2 has continued for the predetermined time t1. If there is, the process proceeds to step S10, and if not, the process proceeds to step S12.

In step S10, the response speed adjustment value a
Is determined to be less than or equal to the initial value a1, and if it is greater than the initial value a1, a new response speed adjustment value a is set to a predetermined value a3 from the current response speed adjustment value a in step S11.
The value obtained by subtracting (here, 0.1) is substituted.

If the value is equal to or smaller than the initial value a1, the process proceeds to step S12 without changing the value of the response speed adjustment value a. This prevents the response speed adjustment value a from becoming smaller than the initial value a1.

In step S12, the motor torque Tm
Is smaller than the manual torque Tc, that is, the motor 1
It is determined whether the output of No. 9 is increasing. If smaller,
A new duty in the pulse modulation control is determined by the equation shown in step S13, and the output to the motor is increased so that the motor torque Tm follows the human power torque Tc at a response speed corresponding to the response speed adjustment value a. Return to Here, K is a constant.

At this time, in detail, as the response speed adjustment value a increases, the new duty increases and the response speed increases, and the motor torque Tm follows the human torque Tc faster. Increases slowly to decrease the response speed, and the motor torque Tm follows the human power torque Tc with a delay.

If the motor torque Tm is equal to or larger than the human torque Tc, a new duty in the pulse modulation control is determined by the equation shown in step S14, and the control is performed so as to quickly follow the human torque Tc with a high response speed. Return to S2.

FIG. 4 shows an example of the relationship between the human-power torque Tc and the motor torque Tm during traveling in the energy saving auto mode.

During OA, the vehicle is running with the maximum value X1 of the human-powered torque Tc being equal to or less than the first predetermined torque T1. During this time, the response speed adjustment value a is set to the initial value a1 (step S1).
1) Energy saving operation is performed. During this operation, the motor 19
The response speed when the output of the motor increases is slow, and the motor torque Tm increases with a delay with respect to the
Becomes larger than the manual torque Tc (Y in the figure),
The response speed of the motor torque Tm is increased by the equation shown in step S14, and the motor torque Tm quickly follows the manual torque Tc and decreases. As a result, the maximum value Y of the motor torque Tm decreases, and the apparent assist ratio decreases. This allows
Power consumption by the motor 19 can be suppressed, and the distance that can be traveled with the assistance of the motor 19 can be increased.

Between A and B, the human torque Tc that changes periodically
In the section in which the maximum value X2 of the torque is equal to or more than the first predetermined torque T1, the value of the maximum value a2 is substituted for the response speed adjustment value a in A in the figure where the manpower torque Tc exceeds the first predetermined torque T1. (Step S5) The mode is switched to the free running. When the mode is switched to the free running operation, the motor torque Tm follows the human power torque Tc quickly even when the output of the motor 19 increases at a high response speed, and the assist ratio increases (almost one to one).

With this, even if the vehicle is approaching a place requiring a large assist such as a hill while traveling in the energy saving auto mode,
The assist ratio by the motor 19 automatically increases,
The human-powered torque Tc can be reduced and the vehicle can travel comfortably.

In this section, even if the periodically changing human-powered torque Tc becomes smaller than the second predetermined torque T2 and the timer starts counting (step S7), the second time within the predetermined time t1 is reached. T2 over specified torque
And the timer is cleared (step S8). As a result, it is possible to prevent the operation mode from switching to the energy-saving operation when the human-power torque Tc temporarily becomes equal to or less than the second predetermined torque T2 due to the periodic change during the free-running operation. It can run comfortably without being repeated over time.

By setting the second predetermined torque T2, which is a reference for switching from the free-running operation to the energy-saving operation, to a value smaller than the first predetermined torque T1 for switching from the energy-saving operation to the free-running operation, the maximum value of the human-powered torque T1 is reduced. When the torque fluctuates in the vicinity of the first predetermined torque T1, it is possible to prevent the energy-saving operation and the free-running operation from being repeatedly switched within a short period of time, and to run comfortably.

During BD, a section in which the maximum value X3 of the human-powered torque Tc becomes smaller than the second predetermined torque T2 again, and this state is maintained for a predetermined time t1 from B when the human-powered torque falls below the second predetermined torque T2. The operation is switched again to the energy saving operation at the point (C in the figure). And the response speed adjustment value a
Is the maximum value a2 during the free running operation and the initial value a during the energy saving operation.
The value is gradually reduced to 1 (step S11), and after reaching the initial value a1 during the energy saving operation, the initial value a1 is obtained.

As described above, when switching from the free running operation to the energy saving operation, the response speed is not switched immediately from the response speed during the free running operation to the response speed during the energy saving operation, but is gradually reduced. Therefore, it is possible to prevent the motor torque Tm from suddenly decreasing and the ride quality from being impaired.

In the energy saving operation, the running speed is reduced as shown in FIG.
(The cycle of the human-powered torque Tc is long), the maximum value of the motor torque Tm is large (Y2>) even if the maximum value X of the human-powered torque Tc is the same as shown in FIG.
Y1), and the apparent assist ratio increases.

Thus, even at the same torque, when the speed is low, the apparent assist ratio can be increased so that the vehicle can run comfortably, and the assist ratio can be reduced at a high speed that does not require assistance by the motor 19 as compared with a low speed. Power consumption can be reduced.

In the above embodiment, the manual torque Tc is used.
Is detected, and the motor torque T
Although m is controlled, the depression force on the pedal may be detected, and the motor torque Tm may be controlled in accordance with the depression force. Also, instead of detecting the load due to human power such as the human torque Tc and the pedaling force, the power by the human power drive unit 7 (the product of the human power torque and the rotation speed of the pedal) is detected, and the motor torque Tm is calculated based on the power. May be controlled.

[0052]

According to the first aspect of the present invention, the response speed when the output of the electric drive system is increased and the response speed when the output is decreased can be respectively changed, so that the apparent assist ratio is changed and the driving condition is changed. The output of the electric drive system suitable for the vehicle can assist the human drive system.

According to the second aspect of the present invention, by reducing the response speed when the output of the electric drive system increases, the apparent assist ratio can be reduced and the power consumption can be suppressed.
Furthermore, the apparent assist ratio automatically increases when the vehicle is traveling at a low speed, and the apparent assist ratio automatically decreases when the vehicle is traveling at a high speed, so that the vehicle can travel comfortably with reduced power consumption.

According to the third aspect of the present invention, by changing the response speed when the output of the electric drive system increases, it is possible to automatically switch between the energy saving operation and the free running operation, and the electric drive system is greatly assisted. If the mode allows comfortable driving and the assistance of the electric drive system is relatively small, energy saving operation can be performed to reduce the power consumption and extend the travelable distance by assisting the electric drive system. .

According to the fourth aspect of the present invention, when the load of the human-powered driving system becomes larger than the first predetermined load, the operation mode is automatically switched from the energy saving operation to the free running operation. Even when the vehicle travels in a place where relatively large assistance is required by an electric drive system such as a hill, the vehicle can travel comfortably.

According to the fifth aspect of the present invention, when the load on the human-powered drive system becomes smaller than the second predetermined load while the vehicle is running in the energy saving mode, the operation mode automatically switches from the free running operation to the energy saving operation. It is possible to extend the distance that can be traveled with the assistance of the electric drive system while suppressing the consumption of power.

According to the sixth aspect of the present invention, during running in the energy saving mode, the free running operation is maintained even if the periodically fluctuating load of the manual drive system temporarily falls below the second predetermined load. It is possible to prevent the rapid running operation and the energy-saving operation from being repeatedly switched in a short time, and to perform comfortable traveling.

According to the seventh aspect of the present invention, when the maximum value of the load of the manual drive system fluctuates near the first predetermined load,
It is possible to prevent the energy-saving operation and the free-running operation from being repeatedly switched within a short period of time, so that the vehicle can run comfortably.

According to the eighth aspect of the present invention, when switching from the free running operation to the energy saving operation, the assistance by the electric drive system can be gradually reduced, so that the vehicle can travel comfortably without impairing the riding comfort.

According to the ninth aspect of the present invention, the mode can be switched according to the user's preference to run.

[Brief description of the drawings]

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

FIG. 2 is a circuit diagram of a control device of the electric assist bicycle.

FIG. 3 is a flowchart in the flat energy saving auto mode of the electric assist bicycle.

FIG. 4 is an example showing a relationship between human torque and motor torque in the energy saving auto mode of the electric assist bicycle.

FIG. 5 is a diagram showing the relationship between human torque and motor torque when the running speed of the electric assist bicycle is low during energy saving driving.

[Explanation of symbols]

7 Human Drive System 10 Electric Drive Unit (Electric Drive System) 21 Microcomputer (Control Means) Tc Human Power Torque (Load by Human Power) Tm Motor Torque (Output of Electric Drive System) T1 First Prescribed Torque (First Prescribed Load) ) T2 second predetermined torque (second predetermined load) t1 predetermined time

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Toshihiro Matsumoto 2-5-5 Keihanhondori, Moriguchi-shi, Osaka Sanyo Electric Co., Ltd. (72) Inventor Seiki Inui 2-chome Keihanhondori, Moriguchi-shi, Osaka No.5-5 in Sanyo Electric Co., Ltd.

Claims (9)

[Claims] 1. An electric assist bicycle in which a human-powered driving system driven by human power and an electric driving system are provided in parallel, and the output of the electric driving system is controlled according to the load of the human-powered driving system. An electric assist bicycle comprising control means capable of controlling a response speed of an electric drive system output at the time of output and a response speed of an electric drive system output at the time of output decrease. 2. The electric assist according to claim 1, wherein the response speed of the output of the electric drive system when the output of the electric drive system increases is slower than the response speed of the output of the electric drive system when the output decreases. bicycle. 3. The energy-saving operation in which the response speed at the time of increase of the output is lower than the response speed at the time of decrease, and the response speed at the time of increase and the response speed at the time of decrease under predetermined conditions are substantially the same. The electric assist bicycle according to claim 1 or 2, wherein control can be performed in an energy saving auto mode for switching between a free running mode and an energy saving mode. 4. The control means controls the energy saving operation when the load is equal to or less than a first predetermined load, and switches from the energy saving operation to a free running operation when the load exceeds the first predetermined load. The electrically assisted bicycle according to claim 3, wherein: 5. The electric assist bicycle according to claim 3, wherein the control unit switches from the free running operation to the energy saving operation when the load becomes equal to or less than a second predetermined load. 6. The method according to claim 3, wherein the control means switches from the free running operation to the energy saving operation when the load is equal to or less than the second predetermined load for a predetermined time. The electric assist bicycle described. 7. The electric assist bicycle according to claim 5, wherein the second predetermined load is smaller than the first predetermined load. 8. The energy-saving operation according to claim 8, wherein, when switching from the free-running operation to the energy-saving operation, the response speed when the output of the electric drive system is increased is gradually delayed from the response speed in the free-running operation. The electric assist bicycle according to any one of claims 3 to 5, wherein the speed is switched to a response speed of the electric assist bicycle. 9. A free running mode in which the response speed when the output of the electric drive system is increased and the response speed when the output is reduced are always substantially the same, and means for manually switching between the free running mode and the energy saving auto mode is provided. 2. The method according to claim 1, wherein
An electrically assisted bicycle according to claim 8.