JP2010264977A - Power-assisted bicycle - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a technique for a power-assisted bicycle to extend a motor-assistable travel distance without impairing its usability. <P>SOLUTION: The power-assisted bicycle, having a human-powered drive system driven by human power and an electrical drive section as an electric-powered drive system driven arranged in parallel, includes a control means capable of control in energy saving mode for switching between an easy-running operation assisted in traveling by a motor at a prescribed assist ratio and an energy saving operation assisted in traveling by the motor at an assist ratio smaller than during the easy-running operation by controlling the output to the motor according to a human-power torque Tc of the human-powered drive system. The control means exercises control by selecting the energy saving operation in S5 when the load of the human-powered drive system is not greater than the first prescribed load and switches from the energy saving operation to the easy-running operation when it exceeds the first prescribed load. The power-assisted bicycle can travel comfortably even where the electric-powered drive system requires relatively large assist during traveling in energy saving auto-mode, for example, during traveling uphill. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to an electrically assisted bicycle that assists a human power drive system with an electric drive system.

  As a conventional power-assisted bicycle, a human-powered drive system driven by a pedaling force of a person stepping on a pedal and an electric drive system driven by a motor powered by a battery are provided in parallel to detect human-power torque and motor torque by pedaling force. A driving mode in which the assist ratio between the manpower torque and the motor torque by the pedal force is 1: 1, and an energy saving auto mode in which the assist ratio is reduced (for example, the motor torque is set to 0.4 with respect to the manpower torque 1); It is known to switch the switch with a manual switch.

  This assist bicycle can be driven comfortably by reducing manual torque by switching to the free running mode with a manual switch when relatively large assistance is required by a motor such as a hill, and even if assistance by a motor such as flat ground is relatively small By switching to the energy saving auto mode with a manual switch when the vehicle can travel, it is possible to extend the distance that can be traveled with the assistance of the electric drive system.

  However, since it is necessary for the driver to switch the switch every time according to the condition of the traveling road, it is troublesome and inconvenient.

  Also, because the assist ratio is constant regardless of the running speed, motor assistance is insufficient when driving at low speeds, and it is not possible to run comfortably. When driving at high speeds, motor assistance is excessive. As a result, the power consumption was large.

Japanese Patent Laid-Open No. 7-309285

  It is an object of the present invention to provide an electrically assisted bicycle that can comfortably and increase the travel distance in which motor assistance is possible without impairing usability.

  A first means for solving the above problem is an electrically assisted bicycle in which a human power drive system driven by human power and an electric drive system are provided in parallel, and the output of the electric drive system is controlled according to the load of the human power drive system. A control means capable of control in an energy-saving auto mode for switching between a free-running operation in which driving assistance is performed by a motor at a predetermined assist ratio and an energy-saving operation in which driving assistance is performed by a motor at an assist ratio smaller than the free-running operation. The means controls the energy-saving operation when the load of the human-powered drive system is equal to or lower 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. To do.

  A second means for solving the above problem is an electrically assisted bicycle in which a human power drive system driven by human power and an electric drive system are provided in parallel, and the output of the electric drive system is controlled according to the load of the human power drive system. A control means capable of control in an energy-saving auto mode for switching between a free-running operation in which driving assistance is performed by a motor at a predetermined assist ratio and an energy-saving operation in which driving assistance is performed by a motor at an assist ratio smaller than the free-running operation. The means is characterized in that the free-running operation is switched to the energy-saving operation when the second predetermined load or less is reached.

  The control means switches from the free-running operation to the energy-saving operation when a state where the load is equal to or less than a second predetermined load continues for a predetermined time.

  Further, the second predetermined load is made smaller than the first predetermined load.

  Further, when the control means switches from the free-running operation to the energy-saving operation, the assist ratio of the electric drive system is gradually reduced from the assist ratio in the free-running operation to switch to the assist ratio in the energy-saving operation. Is.

  Further, a free-running mode in which the assist ratio of the electric drive system is always substantially the same is provided, and means for manually switching between the free-running mode and the energy saving auto mode is provided.

  According to claim 1 of the present invention, by changing the assist ratio of the electric drive system, it is possible to automatically switch between the energy saving operation and the free-running operation, and it is possible to travel comfortably by the free-running operation with a large assist of the electric drive system. When the electric drive system assistance is relatively small, energy saving operation can be performed to reduce the power consumption, and the electric drive system can assist and extend the travelable distance. In addition, when the load of the human power drive system becomes larger than the first predetermined load, it is automatically switched from energy-saving operation to free-running operation, so a relatively large amount of assistance is provided by an electric drive system such as a hill during driving in the energy-saving auto mode. Even if you travel where you need to, you can travel comfortably.

  According to claim 2 of the present invention, by changing the assist ratio of the electric drive system, it is possible to automatically switch between the energy saving operation and the free-running operation, and it is possible to travel comfortably by the free-running operation with a large assist of the electric drive system. When the electric drive system assistance is relatively small, energy saving operation can be performed to reduce the power consumption, and the electric drive system can assist and extend the travelable distance. In addition, if the load on the human power drive system becomes smaller than the second predetermined load while driving in the energy-saving auto mode, the system automatically switches from free-running operation to energy-saving operation. The distance that can be traveled can be extended.

  According to the third aspect of the present invention, during traveling in the energy saving auto mode, the free-running operation is maintained even if the load of the human drive system that fluctuates periodically falls temporarily below the second predetermined load. During this period, it is possible to prevent the free-running operation and the energy-saving operation from being repeatedly switched, and a comfortable driving can be performed.

  According to claim 4 of the present invention, when the maximum value of the load of the human-powered drive system varies in the vicinity of 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 time. Can drive comfortably.

  According to the fifth 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 user can travel comfortably without impairing the ride comfort.

  According to the sixth aspect of the present invention, the vehicle can travel while switching modes according to the user's preference.

1 is a side view of a power-assisted bicycle showing an embodiment of the present invention. It is a circuit diagram of the control apparatus of the same electrically assisted bicycle. It is a flowchart in the energy saving auto mode of the same electrically assisted bicycle. It is an example which shows the relationship between the human power torque and motor torque at the time of the energy saving auto mode of the electric assist bicycle. It is a figure which shows the relationship between the human power torque and motor torque when the travel speed at the time of the energy saving driving | running | working of the electric assist bicycle is slow.

  1 to 5 show an electrically 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 the frame 2 of the electric bicycle main body 1, and the front wheel 3 is steered by the handle 5.

  Reference numeral 7 denotes a human power drive unit as a human power drive system, which includes a pedal 8 and a chain 9. When the user steps on the pedal 8, the rear wheel 4 is rotated via the chain 9. In this example, the chain 9 is a human power transmission member. However, the present 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 serving as an electric drive system is provided at the rotating shaft portion of the rear wheel 4. The electric drive unit 10 includes a motor 19 to be described later. When the electric drive is necessary, the motor 19 is driven to rotate the rear wheel 4 together with the human power drive unit 7.

  Brake levers 11 are attached to the left and right ends of the steering wheel 5 for steering the front wheel 3, and are connected to the brake devices 12 and 13 of the front wheel 3 and the rear wheel 4 by wires 14 and 15, respectively. A brake switch (not shown) is provided in the middle of the wires 14 and 15 to stop energization of the motor 19 when the brake lever 11 is operated.

  A car 16 is provided in front of the handle 5, and a battery unit 17 serving as a power source for the motor 19 is detachably attached to 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 at another location of the frame 2.

  Next, the structure of the control apparatus 18 of the electric drive part 10 is demonstrated based on FIG.

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

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

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

  The microcomputer 21 controls the motor drive circuit 22 based on the output from the human torque sensor 23 and the output from the motor torque sensor 24. The motor drive circuit 22 controls the drive current supplied to the motor 19 by pulse modulation (PWM).

  The motor 19 uses a DC brushless motor, and the rotation 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 electric assist bicycle 1 is switched between a control in a free running mode with an assist ratio of 1: 1 and a control in an energy saving auto mode based on the flowchart of FIG.

  Here, the energy saving auto mode slows down the response speed when the output of the motor 19 is increased and the motor torque Tm follows the human power torque Tc with a delay, and also increases the response speed when the motor output is increased. The torque Tm is composed of a free-running operation in which the human-powered torque Tc quickly follows.

  Next, the operation in the energy saving auto mode will be described based on the flowchart of FIG.

  In step S1, an initial value a1 during energy saving operation (here, a1 = 0.2) is substituted into 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 or not the manpower torque Tc is greater than the first predetermined torque T1, and if so, the response speed adjustment value a is set to the maximum value a2 during the free running operation in step S5 (here a2 = 1.0). Is transferred to step S6, and in the case of T1 or less, the response speed adjustment value a is left as it is, and the process shifts to step S6.

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

  In step S9, it is determined whether or not the timer time has passed the predetermined time t1, that is, whether or not the state where the human torque Tc is smaller than the second predetermined torque T2 has continued for the predetermined time t1, and when the predetermined time t1 has passed. Shifts to step S10, and shifts to step S12 if it has not elapsed.

  In step S10, it is determined whether or not the response speed adjustment value a is equal to or less than the initial value a1, and if it is larger than the initial value a1, a new response speed adjustment value a is changed from the current response speed adjustment value a to a predetermined value a3 in step S11. A value obtained by subtracting (here 0.1) is substituted.

  On the other hand, if the value is equal to or less than the initial value a1, the response speed adjustment value a is not changed and the process proceeds to step S12. This prevents the response speed adjustment value a from becoming smaller than the initial value a1.

  In step S12, it is determined whether or not the motor torque Tm is smaller than the human power torque Tc, that is, whether or not the output of the motor 19 is increasing. If it is 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 torque Tc at the response speed corresponding to the response speed adjustment value a. Return to step S2. Here, K is a constant.

  More specifically, as the response speed adjustment value a is larger, the new duty is faster and larger and the response speed is faster. The motor torque Tm quickly follows the human torque Tc, and the smaller the smaller, the new duty increases slowly. Accordingly, the response speed becomes slow, and the motor torque Tm follows the human power torque Tc with a delay.

  When the motor torque Tm is equal to or higher than the human power 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 power torque Tc with a fast response speed, and the process returns to step S2. .

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

  During the OA, the vehicle travels with the maximum value X1 of the human power 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), and energy saving operation is performed. During this operation, the response speed when the output of the motor 19 increases is slow, the motor torque Tm rises behind the human torque Tc, and after the motor torque Tm becomes larger than the human torque Tc (Y in the figure) The motor torque Tm increases in response speed according to the equation shown in step S14, and decreases following the human power torque Tc quickly. As a result, the maximum value Y of the motor torque Tm decreases, and the apparent assist ratio decreases. Thereby, the 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, in a section where the maximum value X2 of the human power torque Tc that changes periodically is equal to or greater than the first predetermined torque T1, the response speed adjustment value in A in the figure where the human power torque Tc exceeds the first predetermined torque T1. The value of the maximum value a2 is substituted for a (step S5), and the vehicle switches to free-running operation. When switching to the free-running operation, the motor torque Tm quickly follows the human power torque Tc even when the output of the motor 19 increases at a fast response speed, and the assist ratio becomes large (almost 1: 1).

  As a result, even when the vehicle is approaching a place where a large amount of assistance such as a hill is required during traveling in the energy saving auto mode, the assist ratio by the motor 19 is automatically increased, so that the human torque Tc can be reduced and the vehicle can travel comfortably.

  Further, in this section, even if the manually changing torque Tc that is periodically changed is smaller than the second predetermined torque T2 and the timer starts counting (step S7), the second predetermined torque or more is reached within the predetermined time t1. At T2, the timer is cleared (step S8). As a result, it is possible to prevent switching to energy-saving operation when the manpower torque Tc temporarily falls below the second predetermined torque T2 due to a periodic change during traveling in free-running driving. You can drive comfortably without being repeated in time.

  By setting the second predetermined torque T2 serving as 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 power torque T1 is the first value. When it fluctuates in the vicinity of the predetermined torque T1, it is possible to prevent the energy-saving operation and the free-running operation from being repeatedly switched within a short time, and the vehicle can travel comfortably.

  During BD, in a section where the maximum value X3 of the human power torque Tc becomes smaller than the second predetermined torque T2 again, this state is maintained for a predetermined time t1 from B when the human power torque becomes equal to or lower than the second predetermined torque T2. (C in the figure) switches to energy saving operation again. Then, the response speed adjustment value a is gradually reduced from the maximum value a2 during the free running operation to the initial value a1 during the energy saving operation (step S11), and becomes the initial value a1 after reaching the initial value a1 during the energy saving operation. .

  In this way, when switching from free-running operation to energy-saving operation, the response speed is not switched immediately from the response speed during free-running operation to the response speed during energy-saving operation, but is gradually reduced. Thus, it is possible to prevent the motor torque Tm from being suddenly decreased and the riding comfort to be impaired.

  Further, in the energy saving operation, when the traveling speed is slower than between OA in FIG. 4 (the cycle of the human power torque Tc is long), even if the maximum value X of the human power torque Tc is the same as shown in FIG. The maximum value is large (Y2> Y1), and the apparent assist ratio is large.

  This makes it possible to drive comfortably by increasing the apparent assist ratio when the speed is low even with the same torque, and reducing the assist ratio and consuming it at a high speed that does not require assistance from the motor 19 compared to a low speed. Electric power can be reduced.

  In the above embodiment, the human torque Tc is detected and the motor torque Tm is controlled according to the human torque Tc. However, the pedaling force applied to the pedal is detected and the motor torque Tm is controlled according to the pedal force. Also good. Further, instead of detecting a load due to human power such as human power torque Tc or pedaling force, a work rate (product of human power torque and pedal rotation number, etc.) by the human power drive unit 7 is detected, and motor torque Tm is detected based on this work rate. May be controlled.

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 predetermined torque (first predetermined load)
T2 Second predetermined torque (second predetermined load)
t1 time

Claims (6)

  In a motor-assisted bicycle that has a human-powered drive system driven by human power and an electric drive system in parallel, and controls the output of the electric drive system according to the load of the human-powered drive system, it runs smoothly with a motor assisting at a predetermined assist ratio. Control means capable of controlling in energy-saving auto mode to switch between driving and energy-saving driving that performs driving assistance with a motor at an assist ratio smaller than the free-running driving, and the control means has a load of the human-powered driving system as a first load. An electrically assisted bicycle, wherein the energy-saving operation is controlled when the load is below a predetermined load, and the energy-saving operation is switched to the free-running operation when the first predetermined load is exceeded.   In a motor-assisted bicycle that has a human-powered drive system driven by human power and an electric drive system in parallel, and controls the output of the electric drive system according to the load of the human-powered drive system, it runs smoothly with a motor assisting at a predetermined assist ratio. A control means capable of controlling in an energy saving auto mode for switching between driving and energy saving driving for assisting running with a motor at an assist ratio smaller than the free running driving, and the control means is less than a second predetermined load The electric assist bicycle is characterized in that it can be switched from the free-running operation to the energy-saving operation.   The electrically assisted bicycle according to claim 2, wherein the control means switches from the free-running operation to the energy-saving operation when a state where the load is equal to or less than a second predetermined load continues for a predetermined time.   The electrically assisted bicycle according to claim 2 or 3, wherein the second predetermined load is smaller than the first predetermined load.   When the control means switches from the free-running operation to the energy-saving operation, the assist ratio of the electric drive system is gradually reduced from the assist ratio in the free-running operation to switch to the assist ratio in the energy-saving operation. The electrically assisted bicycle according to claim 2, claim 3, claim 4, or claim 7.   6. A free running mode in which the assist ratio of the electric drive system is always substantially the same is provided, and means for manually switching between the free running mode and the energy saving auto mode is provided. The electric assist bicycle described in 1.