JP2016107738A - Electric power-assisted bicycle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an electric power-assisted bicycle capable of improving traveling stability in starting and at a low speed and maintaining stability during turning.SOLUTION: An electric power-assisted bicycle comprises: an electric motor 30 generating auxiliary driving force on a wheel of the bicycle; a vehicle speed sensor 36 detecting a vehicle speed; a steering angle sensor 38 detecting a rotation angle of a handle; and an arithmetic processing unit 20, when a lower vehicle speed than a predetermined speed is detected by the vehicle speed sensor 36, controlling the electric motor 30 to generate predetermined auxiliary driving force according to the rotation angle detected by the steering angle sensor 38, and when a vehicle speed equal to or higher than the predetermined speed is detected by the vehicle speed sensor 36, controlling the electric motor 30 to generate predetermined auxiliary driving force for the time of steady traveling.SELECTED DRAWING: Figure 2

Description

  The present invention relates to a battery-assisted bicycle that uses an electric motor to generate an auxiliary driving force corresponding to an input torque applied to a pedal, and drives a wheel auxiliary by the auxiliary driving force.

  An electrically assisted bicycle including a human-powered drive system that supplies input torque applied to a pedal to a wheel, and an auxiliary drive power drive system that supplies auxiliary drive force from the electric motor to the wheel in response to the pedaling force applied to the pedal. It has been known.

  In addition, some types of battery-assisted bicycles transmit the input torque applied to the pedal to the rear wheels and transmit the auxiliary driving force from the motor to the front wheels, and the input torque applied to the pedal and the auxiliary driving force from the motor. There is a type that transmits both to the rear wheel.

  In such a battery-assisted bicycle, a technique for controlling the auxiliary driving force in accordance with the steering angle of the steering wheel is known.

  For example, in Patent Document 1, the electric power supplied from the battery power source to the electric motor that assists the stepping of the foot pedal is represented by k / θ obtained by multiplying the reciprocal of the output steering angle θ of the steering angle sensor by a coefficient k. It has been proposed to limit by multiplying the rudder angle function.

  Further, Patent Document 2 proposes a front-wheel drive electric bicycle in which a handle post angle detection unit that detects a handle angle is provided on a handle post and the electric drive of an assist motor is controlled according to the detected handle angle.

  Patent Document 3 proposes an electrically assisted bicycle that performs control to weaken the assist force by a motor when the steering angle detected by the steering angle detection device exceeds a predetermined value.

JP-A-9-95287 JP 2002-19684 A JP 2011-230664 A

  As in Patent Documents 1 to 3, by controlling the auxiliary driving force in accordance with the rudder angle, it is possible to obtain effects such as prevention of lane departure and overturning, and improvement in operability. Here, when traveling at a low speed, it is possible to prevent a deviation from the traveling path, a fall, or the like by controlling the auxiliary driving force according to the steering angle as in Patent Documents 1 to 3. However, in situations such as normal speed driving or high speed driving, if the auxiliary driving force is reduced according to the rudder angle, there may be adverse effects such as greater entrainment and difficulty in turning from straight to straight. Therefore, there is room for improvement.

  The present invention has been made in consideration of the above facts, and provides a battery-assisted bicycle that can improve running stability at the time of start and low speed and can maintain stability at the time of turning. Objective.

  In order to achieve the above object, a battery-assisted bicycle according to the present invention includes a generating means for generating auxiliary driving force for rotating a bicycle wheel, a vehicle speed detecting means for detecting a vehicle speed, and at least one of a handle and a roll. When a vehicle speed lower than a predetermined speed is detected by an angle detection means for detecting a rotation angle and the vehicle speed detection means, a predetermined auxiliary driving force is applied according to the rotation angle detected by the angle detection means. The generating means is controlled so as to generate, and when the vehicle speed detecting means detects a vehicle speed equal to or higher than a predetermined speed, the generating means is controlled so as to generate a predetermined auxiliary driving force during steady running. And a control means.

  In addition, the battery-assisted bicycle according to the present invention includes a generating means for generating auxiliary driving force for rotating a bicycle wheel, a vehicle speed detecting means for detecting a vehicle speed, and an angle detection for detecting a rotation angle of at least one of a handle and a roll. And a vehicle speed lower than a predetermined speed is detected by the vehicle speed detection means, and the angle detection means detects the rotation angle that is equal to or greater than a predetermined angle. The generating means is controlled to generate a predetermined auxiliary driving force in accordance with the rotation angle, and when the vehicle speed more than a predetermined speed is detected by the vehicle speed detecting means, and the vehicle speed detecting means When a vehicle speed lower than the speed is detected and the rotation angle smaller than a predetermined angle is detected by the angle detection means, And control means for controlling the generating means to generate the auxiliary driving force when meta steady running, and a.

  The control means may control the generating means so that a smaller auxiliary driving force is generated as the rotation angle detected by the angle detecting means is larger as the predetermined auxiliary driving force.

  The battery-assisted bicycle according to the present invention further includes torque detection means for detecting torque applied to the pedal, and crank angle detection means for detecting a crank angle, wherein the control means includes the vehicle speed detection means, The generating means is controlled to generate the predetermined auxiliary driving force based on the detection results of the torque detecting means, the crank angle detecting means, and the angle detecting means, and the vehicle speed detecting means, the torque detecting means The generating means may be controlled so as to generate the auxiliary driving force during the steady running based on the detection results of the means and the crank angle detecting means.

  According to the battery-assisted bicycle according to the present invention, it is possible to provide a battery-assisted bicycle that can improve the running stability at the time of starting or at a low speed and can maintain the stability at the time of turning.

1 is a side view showing a configuration of a battery-assisted bicycle according to an embodiment of the present invention. It is a block diagram which shows the structure of the electric system of the battery-assisted bicycle which concerns on embodiment of this invention. (A) is a graph which shows a steering angle and an assist ratio, (B) is a graph which shows the torque change with respect to time passage, (C) is a graph which shows the horizontal direction distance with respect to time passage. It is a flowchart which shows an example of the flow of the process performed with the arithmetic processing apparatus of the battery-assisted bicycle which concerns on embodiment of this invention. (A) is a figure for demonstrating the auxiliary | assistant drive force and the notch | incision of a steering wheel at the time of low speed and start, and (B) is a figure which shows the swelling of turning by the auxiliary drive force at the time of low speed and start.

  Embodiments of the present invention will be described below with reference to the drawings. In the drawings, the same or equivalent components and parts are denoted by the same reference numerals. Further, in the following description, an example in which the present invention is applied to a type of battery-assisted bicycle that drives the rear wheels with the input torque applied to the pedal by the driver and drives the front wheels with the auxiliary driving force by the electric motor. To do.

  FIG. 1 is a side view showing a configuration of a battery-assisted bicycle according to an embodiment of the present invention.

  The battery-assisted bicycle 1 has a frame including a front fork 11, a head pipe 12, a down tube 13, a seat tube 14, a seat stay 15, and a chain stay 16. The front wheel 21 is rotatably attached to the front fork 11, and the rear wheel 22 is rotatably attached to the intersection of the seat stay 15 and the chain stay 16.

  A handle stem 23 is rotatably inserted into the head pipe 12, and a handle 24 is attached to the upper end of the handle stem 23. On the other hand, a seat post 25 is fitted to the seat tube 14, and a saddle 26 is attached to the upper end of the seat post 25.

  The pedal 27 is connected to a sprocket (not shown) via a crank 28. The sprocket rotates when the driver applies pedaling force to the pedal 27, and the driving force is transmitted to the rear wheel 22 via the chain 29 as the sprocket rotates.

  The electric motor 30 is mounted on the axle of the front wheel 21 and generates a driving force that rotates the front wheel 21. The rotation of the electric motor 30 is decelerated by a reduction mechanism (not shown) and transmitted to the front wheels 21. The electric motor 30 can be composed of, for example, a brushless DC motor.

  Electric power for driving the electric motor 30 is supplied from a battery 31 detachably provided along the seat tube 14. The battery 31 is composed of, for example, a lithium ion secondary battery, and can be repeatedly used by charging.

  FIG. 2 is a block diagram showing a configuration of the electric system of the battery-assisted bicycle 1 according to the embodiment of the present invention.

  As shown in FIG. 2, the battery-assisted bicycle 1 includes a torque sensor 32, a crank angle sensor 34, a vehicle speed sensor 36, a rudder angle sensor 38, a roll sensor 39, a battery 10, an operation / display unit 18, an arithmetic processing unit 20, a motor. A drive circuit 40 and an electric motor 30 are provided.

  The torque sensor 32 detects the magnitude of the input torque due to human power applied to the pedal 27, and generates a torque detection signal indicating the magnitude of the detected input torque. The torque detection signal generated by the torque sensor 32 is input to the arithmetic processing unit 20. As the torque sensor 32, for example, a known torque sensor using a magnetostriction effect that does not have a mechanical contact portion with respect to the crankshaft can be applied.

  The crank angle sensor 34 detects an angle of the crank 28 with respect to a predetermined reference position, and generates a crank angle signal indicating the detected crank angle. The generated crank angle signal is input to the arithmetic processing unit 20. The crank angle sensor 34 can be configured by a Hall element, a magnetic sensor, a rotary encoder, or the like provided on the crank 28.

  The vehicle speed sensor 36 detects the rotational speed of the wheel and generates a speed signal indicating the detected rotational speed. The generated speed signal is input to the arithmetic processing unit 20. The vehicle speed sensor 36 can be configured by, for example, a hall element or a magnetic sensor provided on a wheel.

  The steering angle sensor 38 detects an angle with respect to the reference position (hereinafter referred to as a steering angle) using the straight travel of the handle 24 as a reference position, and generates a steering angle signal indicating the detected steering angle. The generated steering angle signal is input to the arithmetic processing unit 20. The rudder angle sensor 38 can be configured by, for example, a hall element, a rotary encoder, or the like provided on the handle stem 23, the head pipe 12, or the like.

  The roll sensor 39 detects a roll angle that is an inclination of the bicycle 1 with respect to the vertical, and generates a roll signal indicating the detected roll angle. The generated roll signal is input to the arithmetic processing unit 20. As the roll sensor 390, for example, a gyro sensor can be applied. In the present embodiment, the roll is detected by a roll sensor such as a gyro sensor, but the roll may be determined from the vehicle speed and the steering angle.

  The operation / display unit 18 lights a power button (not shown), a mode selection button (not shown) that accepts an input operation for selecting an assist ratio setting (assist mode), and a light (not shown). And various buttons such as a light button (not shown) for receiving an input operation for turning off the light. When various buttons such as a mode selection button and a light button are operated, the operation / display unit 18 notifies the arithmetic processing unit 20 that these buttons have been operated. The operation / display unit 18 has a display unit (not shown) for displaying the state of the host vehicle including the remaining battery level, the currently selected assist mode, and lighting / extinguishing of the lights. Information regarding the state of the host vehicle is supplied from the arithmetic processing unit 20.

  The arithmetic processing unit 20 includes, for example, an LSI (Large Scale Integration) in which a single semiconductor chip is integrated with a computer system including a CPU (Central Processing Unit), a memory, an input / output circuit, a timer circuit, and the like. .

  The arithmetic processing unit 20 receives power from the battery 10 and operates. In addition, the arithmetic processing device 20 performs control for supplying the electric power of the battery 10 to the electric motor 30 to drive the electric motor 30. The arithmetic processing unit 20 controls driving of the electric motor 30 based on signals from various sensors. Specifically, the arithmetic processing unit 20 generates a motor drive command value based on the detection results of the torque sensor 32, the crank angle sensor 34, the vehicle speed sensor 36, and the steering angle sensor 38. Then, by supplying the generated motor drive command value to the motor drive circuit 40, the operation of the motor drive circuit 40 is controlled.

  The motor drive circuit 40 supplies drive power corresponding to the auxiliary drive force indicated by the motor drive command value supplied from the arithmetic processing device 20 from the battery 10 to the electric motor 30. The torque sensor 32, the crank angle sensor 34, the vehicle speed sensor 36, the rudder angle sensor 38, the roll sensor 39, and the operation / display unit 18 are also operated by electric power supplied from the battery 10.

  The motor drive circuit 40 and the electric motor 30 correspond to the generation means, the vehicle speed sensor 36 corresponds to the vehicle speed detection means, the steering angle sensor 38 and the roll sensor 39 correspond to the angle detection means, and the arithmetic processing unit 20 It corresponds to the control means.

  By the way, the battery-assisted bicycle 1 according to the present embodiment is configured to drive the front wheels with the auxiliary driving force generated by the electric motor 30 as described above. For this reason, when the steering angle of the handle 24 is large and the auxiliary driving force is generated on the wheels, there is a possibility that the generated driving force may bend at a steeper angle that is larger or steeper than the passenger intends. In addition, the balance may be lost in the case of low speed traveling such as when starting. The above problem may occur even in the configuration in which the auxiliary driving force is applied to the rear wheel 22. However, in the configuration in which the auxiliary driving force is generated in the front wheel 21 as in the present embodiment, the above-described problem is particularly likely to occur.

  Therefore, the arithmetic processing device 20 of the battery-assisted bicycle 1 according to the present embodiment has a steering angle and roll when the vehicle speed is lower than a predetermined speed (for example, when starting) and the steering angle is larger than a predetermined angle. The driving of the electric motor 30 is controlled so as to obtain an auxiliary driving force according to the angle. Specifically, the auxiliary driving force corresponding to the steering angle and roll angle is calculated by the arithmetic processing unit 20 using the vehicle speed v, the input torque TPedal to the pedal 27, the roll angle θRoll, the steering angle θSteer, and the crank angle θCrank as parameters. Auxiliary driving force TAssist = f (v, TPedal, θRoll, θSteer, θCrank). Then, the driving of the electric motor 30 is controlled by outputting a command value indicating the auxiliary driving force obtained by the arithmetic processing unit 20 to the motor driving circuit 40. For example, as shown in FIG. 3A, when the vehicle speed is lower than a predetermined speed, control is performed such that the assist ratio decreases as the rudder angle increases. In the example of FIG. 3 (A), an example in which the auxiliary driving force is linearly reduced by 15 degrees and the steering angle becomes 0 thereafter. As a result, as shown by the solid line in FIG. 3 (B), the torque change with the lapse of time decreases the auxiliary driving force with respect to the dotted line in FIG. 3 (B) indicating the case where the auxiliary driving force is not reduced. Further, as the auxiliary driving force decreases, the lateral distance with respect to the passage of time decreases as shown in FIG. 3C, and the dangerous behavior decreases. Note that the dotted line in FIG. 3C shows the case where the auxiliary driving force is not reduced, the solid line shows the case where the auxiliary driving force is reduced, and the alternate long and short dash line shows the case where there is no auxiliary driving force. In the example of FIG. 3C, when the auxiliary driving force is decreased, the lateral distance is twice as long as that without the auxiliary driving force, and when the auxiliary driving force is not decreased, the distance is 3 with no auxiliary driving force. .5 times the lateral distance.

  Further, in the present embodiment, when the vehicle speed is lower than a predetermined speed and the steering angle is smaller than a predetermined angle, and when the vehicle speed is steady traveling at a predetermined vehicle speed or higher, auxiliary driving force during steady traveling is obtained. The drive of the electric motor 30 is controlled so that The auxiliary driving force at the time of steady running is obtained by the arithmetic processing unit 20 using the auxiliary driving force TAssist = f (v, TPedal, θCrank) using the vehicle speed v, the input torque TPedal to the pedal 27, and the crank angle θCrank as parameters. Then, the driving of the electric motor 30 is controlled by outputting a command value indicating the auxiliary driving force obtained by the arithmetic processing unit 20 to the motor driving circuit 40.

  Subsequently, specific processing performed in the arithmetic processing unit 20 will be described. FIG. 4 is a flowchart illustrating an example of a flow of processing performed by the arithmetic processing device 20 of the battery-assisted bicycle 1 according to the embodiment of the present invention. The process of FIG. 4 starts when the power is turned on by the power button of the operation / display unit 18.

  In step 100, the arithmetic processing unit 20 acquires the detection result of the vehicle speed sensor 36 and proceeds to step 102.

  In step 102, the arithmetic processing unit 20 acquires the detection result of the crank angle sensor 34 and proceeds to step 104.

  In step 104, the arithmetic processing unit 20 acquires the detection result of the torque sensor 32 and proceeds to step 106.

  In step 106, the arithmetic processing unit 20 determines whether or not the detection result of the vehicle speed sensor 36 is equal to or higher than a predetermined speed, and if the determination is affirmed, the process proceeds to step 108, and if not, the process proceeds to step 108. 110.

  In step 108, the arithmetic processing unit 20 performs auxiliary driving force control during steady running, and the process proceeds to step 116. That is, the arithmetic processing unit 20 calculates auxiliary driving force TAssist = f (v, TPedal, θCrank) using the vehicle speed v, the input torque TPedal to the pedal 27, and the crank angle θCrank as parameters. And the arithmetic processing unit 20 controls the drive of the electric motor 30 so that it may become the calculated | required auxiliary drive force. That is, when the vehicle speed is equal to or higher than a predetermined speed, a steady auxiliary driving force is applied even during turning, so that stability during turning can be maintained.

  On the other hand, in step 110, the arithmetic processing unit 20 acquires the detection result of the steering angle sensor 38 and proceeds to step 112.

  In step 112, the arithmetic processing unit 20 determines whether or not the rudder angle detected by the rudder angle sensor 38 is greater than a predetermined threshold value. If the determination is negative, the process proceeds to step 108 described above, and affirmative. If so, the process proceeds to step 114.

  In step 114, the arithmetic processing unit 20 performs auxiliary driving force control according to the steering and the roll angle, and the process proceeds to step 116. That is, the arithmetic processing unit 20 uses the vehicle speed v, the input torque TPedal to the pedal 27, the roll angle θRoll, the steering angle θSteer, and the crank angle θCrank as parameters, and the auxiliary driving force TAssist = f (v, TPedal, θRoll, θSteer, θCrank) is obtained. And the arithmetic processing unit 20 controls the drive of the electric motor 30 so that it may become the calculated | required auxiliary drive force. Here, the control of the auxiliary driving force in step 114 includes correction of the assist ratio. For example, as described above, as shown in FIG. 3A, when the vehicle speed is lower than a predetermined speed, control is performed such that the assist ratio decreases as the rudder angle increases. Thereby, when the steering angle is larger than the threshold value at the time of starting or at a low speed, the driving stability at the time of starting or at a low speed can be improved by reducing the auxiliary driving force. In this embodiment, the auxiliary driving force is obtained by TAssist = f (v, TPedal, θRoll, θSteer, θCrank), but θRoll or θSteer is omitted, and the auxiliary driving force is determined according to the roll angle or the steering angle. You may make it control.

  In step 116, the arithmetic processing unit 20 determines whether or not the power button of the operation / display unit 18 has been operated to turn off the power. If the determination is negative, the process returns to step 100 and the above-described processing is repeated. If the determination is affirmative, the series of processing ends.

  As described above, in this embodiment, when the steering angle is larger than the threshold value when the vehicle speed is lower than a predetermined speed or when the vehicle speed is low, auxiliary driving force control is performed according to the steering and roll angles, and the vehicle speed is determined in advance. In the case of steady running at a speed higher than that, auxiliary driving force control during steady running is performed. That is, auxiliary driving force control corresponding to the rudder angle and roll angle is performed only at the time of starting or at a low speed. This prevents the handle 24 from being cut with respect to the solid line arrow by the auxiliary driving force at low speed or at the start as shown by the dotted line arrow in FIG. As shown by, it is possible to turn stably by reducing the auxiliary driving force. In addition, as shown by the dotted line in FIG. 5B, the bicycle 1 does not swell at the time of turning at a low speed or at the start, and the intention is stable as shown by the solid line arrow in FIG. 5B. It is possible to turn with the turning radius.

  In addition, when the vehicle speed is equal to or higher than a predetermined speed, the auxiliary driving force is controlled during steady driving without limiting the auxiliary driving force. A stable turn can be performed without breaking the wheel.

  In the above embodiment, when a vehicle speed lower than a predetermined speed is detected, auxiliary driving force control is performed according to the steering angle and the roll angle, and in the case of steady running where the vehicle speed is equal to or higher than the predetermined speed, You may make it perform auxiliary drive force control at the time of steady driving | running | working.

  In the above-described embodiment, the rear wheel is driven by the input torque applied to the pedal by the driver and the front wheel is driven by the auxiliary driving force of the electric motor as an example. However, it is not limited to this. For example, a battery-assisted bicycle that transmits both the input torque applied to the pedal and the auxiliary driving force by the electric motor to the rear wheels may be applied. Alternatively, an electric auxiliary bicycle that transmits both the input torque applied to the pedal and the auxiliary driving force by the electric motor to the rear wheels and drives the front wheels by the auxiliary driving force by the electric motor may be applied.

  Further, the present invention is not limited to the above, and it is needless to say that various modifications can be made without departing from the gist of the present invention.

DESCRIPTION OF SYMBOLS 1 Motor-assisted bicycle 20 Arithmetic processor 30 Electric motor 32 Torque sensor 36 Vehicle speed sensor 38 Steering angle sensor 39 Roll sensor 40 Motor drive circuit

Claims (4)

Generating means for generating auxiliary driving force for rotating the bicycle wheel;
Vehicle speed detection means for detecting the vehicle speed;
An angle detection means for detecting a rotation angle of at least one of the handle and the roll;
When the vehicle speed detecting means detects a vehicle speed lower than a predetermined speed, the generating means is controlled so as to generate a predetermined auxiliary driving force according to the rotation angle detected by the angle detecting means. Control means for controlling the generating means so as to generate a predetermined auxiliary driving force during steady running when a vehicle speed equal to or higher than a predetermined speed is detected by the vehicle speed detecting means;
A power-assisted bicycle equipped with Generating means for generating auxiliary driving force for rotating the bicycle wheel;
Vehicle speed detection means for detecting the vehicle speed;
An angle detection means for detecting a rotation angle of at least one of the handle and the roll;
When a vehicle speed lower than a predetermined speed is detected by the vehicle speed detecting means, and the rotation angle equal to or larger than a predetermined angle is detected by the angle detecting means, the rotation angle detected by the angle detecting means is In response, the generating means is controlled to generate a predetermined auxiliary driving force, and when the vehicle speed detecting means detects a vehicle speed equal to or higher than a predetermined speed, and lower than the speed determined in advance by the vehicle speed detecting means. Control means for controlling the generating means so as to generate a predetermined auxiliary driving force during steady running when the vehicle speed is detected and the rotation angle smaller than the predetermined angle is detected by the angle detecting means. When,
A power-assisted bicycle equipped with   The control means controls the generating means so that a smaller auxiliary driving force is generated as the rotation angle detected by the angle detecting means is larger as the predetermined auxiliary driving force. The battery-assisted bicycle described in 1. Torque detecting means for detecting torque applied to the pedal; and crank angle detecting means for detecting a crank angle;
The control means controls the generating means to generate the predetermined auxiliary driving force based on detection results of the vehicle speed detecting means, the torque detecting means, the crank angle detecting means, and the angle detecting means. The generating means is controlled so as to generate auxiliary driving force during the steady running based on detection results of the vehicle speed detecting means, the torque detecting means, and the crank angle detecting means. The battery-assisted bicycle according to any one of the above.