JP2014195367A - Electric vehicle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an electric vehicle in which a brake wire required for a brake operation mechanism is omitted.SOLUTION: The electric vehicle determines whether the vehicle is in a travel state or in a stand-by state based on vehicle speed. When the vehicle is in the stand-by state, a drive motor M is locked during brake operation, and when in the travel state, reverse torque whose output value is determined according to a brake operation amount is outputted from the drive motor M. When the brake operation is not detected, brake control is not performed.

Description

  The present invention relates to an electric vehicle, and more particularly, to an electric vehicle that travels using a rotational speed of a pedal that a driver rides as a drive command.

2. Description of the Related Art Conventionally, as represented by a bicycle, there is a vehicle that moves forward by transmitting driving force to a driving wheel via a chain by stroking a crank pedal connected to an input shaft with left and right feet. In addition to such a mechanical power transmission mechanism, an assist bicycle that reinforces the driving force with an electric motor has been proposed.
On the other hand, as described in the following patent document, there is proposed a bicycle that does not have a mechanical transmission mechanism and is electrically connected to an input device using a pedal and a drive device that drives a drive wheel.

JP 2001-114184 A JP 2010-120599 A

In the conventional electric bicycle, at the time of acceleration, the pedal is used as an accelerator, and an output corresponding to the amount of rotation of the pedal is output from the drive wheel.
By the way, with respect to bicycles, there is a demand for using bicycles at destinations such as travel destinations and business trip destinations. For such applications, a bicycle having a structure that can be compactly reduced by disassembling or folding a part of the vehicle body has been proposed. Since the electric vehicle cited as the conventional example does not have a power transmission mechanism, the design range for realizing compactness is widened, and the electric vehicle has an advantageous structure for achieving compactness. However, the following problems remain in the bicycle braking device. In the conventional configuration including the above-described prior art documents, the operation amount is transmitted by the brake wire connecting the brake lever and the braking device, and the brake operation is performed.

However, since this brake wire becomes an obstacle when disassembling and folding the vehicle for compactness, it is necessary to remove the brake wire or change the brake wire to an extreme shape when disassembling and folding. There is. Such an operation has a problem in that the work is complicated and the braking device is broken. Furthermore, the brake wire is unsightly in appearance, and there is a concern that problems such as being caught by touching clothes during driving may occur.
An object of the present invention is to provide an electric vehicle in which a brake wire necessary for a brake operation mechanism is omitted.

The present invention for solving the above problems has the following configuration.
(1) a vehicle body on which the driver is placed;
A vehicle having front and rear wheels supported respectively on the front and rear of the vehicle body;
A pedal rotating unit having a crank that rotates about a rotation axis, and a pedal that is provided at the tip of the crank and that receives a pedaling force of a driver;
A motor for driving at least one of the front wheel or the rear wheel;
Braking operation means for the driver to input a braking operation;
Braking detection means for detecting a braking operation of the braking operation means;
Vehicle speed detecting means for detecting the vehicle speed of the vehicle;
An electric vehicle provided with a braking control means for braking the vehicle by controlling the rotation of the motor based on the vehicle speed detected by the vehicle speed detecting means when a braking operation by the braking detecting means is detected.

(2) The braking control means includes:
Vehicle state determination means for determining whether the vehicle is in a standby state or a running state based on the vehicle speed detected by the vehicle speed detection means;
The motor lock unit according to (1), further including: a motor lock unit that sets the rotation of the motor to 0 when it is determined that the vehicle state determination unit is in a standby state and braking is detected by the brake detection unit. Electric vehicle.

(3) The braking control means includes:
The electric vehicle according to (2), further comprising: a motor reverse rotation unit that generates a torque in the reverse rotation direction of the motor when the vehicle state determination unit determines that the vehicle is in a traveling state.

(4) The electric vehicle according to (2) or (3), wherein the vehicle state determination unit determines that the vehicle is in a standby state when the vehicle speed detected by the vehicle speed detection unit is smaller than a predetermined value.

(5) The braking detection means detects a brake operation amount,
The electric vehicle according to (4), wherein the motor reverse rotation means determines reverse rotation torque in accordance with a brake operation amount detected by the braking detection means.

  According to the first aspect of the present invention, when the brake operation is detected, the braking control according to the vehicle speed is performed, so that it is possible to perform the braking control in accordance with the driver's braking intention. Further, since the brake wire can be omitted, it is not necessary to attach the brake wire to the vehicle body, which is aesthetically advantageous and can be more safely driven without fear of getting involved with the driver's clothes.

  According to the second aspect of the present invention, it is determined based on the vehicle speed whether the vehicle is in a traveling state in which the vehicle is traveling or in a standby state before traveling, and when a braking operation is detected in the standby state. Since the motor is locked, for example, a general operation such as a general bicycle or an assist bicycle can be reproduced by holding the brake lever in a standby state such as when starting and maintaining the vehicle in a stopped state.

According to the third aspect of the present invention, in the running state, braking is performed by reversing the motor by detecting the brake operation, and the driver may feel a braking feeling similar to that of a general bicycle. it can.
According to the fourth aspect of the present invention, since it is determined whether the vehicle is in the standby state or the traveling state based on whether the vehicle speed is small with reference to a predetermined value, it is possible to easily distinguish between the standby state and the traveling state.
According to the fifth aspect of the present invention, since the reverse rotation torque of the motor is determined according to the brake operation amount, the braking force can be adjusted according to the brake operation amount.

1 is an overall side view of an electric vehicle according to the present invention. It is a block diagram which shows the structure of the electric system in the electric vehicle of this invention. It is a block diagram which shows a part of motor control circuit of the electric vehicle of this invention. It is a flowchart which shows the brake control content of the electric vehicle of this invention.

  Hereinafter, preferred embodiments of the vehicle of the present invention will be described in detail with reference to the accompanying drawings. FIG. 1 shows an embodiment of an electric vehicle 1 according to the present invention, and is an overall perspective view of an electric bicycle. The vehicle body 2 includes an operation unit 20 and a main body 21. The operation unit 20 includes a handle 22, a stem 221 that is a rotation shaft of the handle 22, and a front wheel 23f. The main body 21 is composed of, for example, a single base or a frame in which a plurality of members are combined. In this embodiment, the main body 21 is composed of a single base. A stem 221 of the handle 22 is rotatably supported by the front end head tube 211 of the main body 21, and a rear wheel 23 b that is a driven wheel is supported at the rear end, and the control unit CU and the battery unit BU are connected to each other. It is installed. The handle 22 is provided with a brake lever 224 as a braking operation means for inputting a brake operation to the handle grip portions 223 at both ends. The brake lever 224 is provided with a brake sensor BBS as a brake detection means for detecting an operation amount for braking.

  On the other hand, a column 24 is erected at the center of the main body 21, and a power generation unit GU is provided at the base end of the column 24. A saddle 241 is attached to the tip of the support column 24. A front fork 222 is connected to the lower end portion of the stem, and a front wheel 23f that is a drive wheel is provided at the front end of the front fork 222. A drive motor M is provided at the central shaft portion of the front wheel 23f. In this embodiment, an in-wheel motor is used as the drive motor. The output shaft of the in-wheel motor is fixed to the front fork 222. The front wheel 23f is rotationally driven as a drive wheel by the drive motor M. The drive motor M is provided with a drive wheel rotational speed sensor MRS and a drive motor current sensor MTS as vehicle speed detecting means. The drive wheel rotational speed sensor MRS detects the rotational speed of the drive wheel, and the drive motor current sensor The MTS detects the current value flowing through the drive motor. The torque output from the drive motor M can be known from this current value.

  The drive motor M functions as a braking means at the time of braking, and switches between a locked state and a reverse torque output state according to the operation amount of the brake lever 224 and the vehicle speed.

  Input shafts as rotating shafts protrude from the left and right sides of the power generation unit GU. Each left and right input shaft has a crank shaft 250L in which cranks 25L and 25R are connected in opposite directions (the right crank shaft 250R is illustrated). Has not been). Pedals 251L and 251R are rotatably supported at the ends of the left and right cranks 25L and 25R, respectively. The crankshaft 250L, the cranks 25L and 25R, and the pedals 251L and 251R constitute a pedal rotating unit.

  The power generation unit GU includes a power generator G, and the pedaling force applied to the cranks 25L and 25R is transmitted to the rotor of the power generator G as a rotational torque via the input shaft. The power generation unit GU may include a mechanical transmission mechanism that transmits torque applied to the input shaft to the generator G, such as a transmission. The power generation unit GU further includes a generator current sensor PTS, a pedal torque sensor PTS as a torque detection means, and a pedal rotation speed sensor PRS. The pedal torque sensor PTS is a sensor that detects torque transmitted from the pedal when the driver depresses, and the pedal rotation speed sensor PRS detects the rotation speed of the pedal. The generator current sensor PTS detects the value of current flowing through the generator. This current value is intended to provide a drag force applied to the pedal by the generator.

  The control unit CU includes a vehicle control circuit EC configured by an integrated circuit and a memory, a battery control circuit BC that controls discharging and charging of a battery, a generator control circuit GC, and a motor control circuit MC. The battery unit BU provided adjacent to the control unit CU includes a battery BT, a battery current sensor BIS that detects a current value output from the battery BT, and a voltage sensor BVS that detects a voltage output from the battery BT. I have. The battery unit BU is detachably provided mechanically and electrically with respect to the vehicle body 2 and is configured to be rechargeable by an external power source in a state of being detached from the vehicle body 2.

  The electric power of the battery BT is supplied to the drive motor M, and the regenerative electric power is supplied to the battery BT when the drive motor M is regenerated. In addition, when the pedal drag is generated by the generator G, the electric power of the battery BT is supplied to the generator G, and the electric power generated by the generator G is supplied to the battery BT and stored. The drive motor M and the generator G are actuators that mutually convert energy between electrical energy and mechanical rotational energy, and the drive motor M mainly converts electric power into rotational torque, but rotates during regeneration. Convert torque to electric power. The generator G mainly converts rotational torque into electric power. However, when controlling the number of rotations of the pedal, the generator control circuit GC may convert electric power into rotational torque. The drive motor M functions as a braking means by controlling the rotation speed.

  FIG. 2 is a block diagram showing the configuration of the control system of the present invention. The control system includes a vehicle control circuit EC, a battery control circuit BC, a generator control circuit GC, and a motor control circuit MC, and an instruction signal is supplied from each vehicle control circuit EC to another control circuit. Detection values are input from the sensors to the vehicle control circuit EC, and based on the input values, the value of the drag applied to the rotating shaft of the pedal, the target rotational speed of the pedal, the target vehicle speed, and the like are determined. For example, the target vehicle speed is determined based on the pedal torque value input from the pedal torque sensor PTS, and when the pedal torque is not detected, the output torque of the drive motor M is zero, that is, the drive motor M is in the free rotation state. It becomes.

The generator control circuit GC controls the rotation of the generator so that the actual pedal rotation speed becomes the target rotation speed based on the instruction of the pedal target rotation speed from the vehicle control circuit EC. Specifically, by controlling the current of the generator, resistance is given to the rotation of the rotor of the generator, and the rotation speed of the pedal is controlled.
The motor control circuit MC controls the electric power supplied to the drive motor M so that the actual vehicle speed becomes the target value based on the instruction of the target vehicle speed value from the vehicle control circuit EC. Further, during regeneration, the battery circuit is switched and controlled so that regenerative power obtained from the drive motor can be supplied to the battery BT. Further, the motor control circuit MC controls the supplied electric power so that the torque is generated in the drive motor M based on the reverse torque value supplied from the vehicle control circuit EC during the braking operation.

  The battery control circuit BC performs mode switching based on an instruction from the vehicle control circuit EC. The battery control circuit BC is divided into a generator system and a drive motor system. For each, a mode for supplying power to the drive motor M, a mode for charging regenerative power from the drive motor M, and a power supply to the generator G are provided. The mode is switched between the mode to perform and the mode to charge the electric power generated from the generator G.

  FIG. 3 shows a part of the motor control circuit MC. The drive motor M is a DC motor, and is a circuit diagram for switching the direction of the current supplied to the drive motor M. By changing the direction of the supplied current, the drive motor M rotates in the forward drive state in which the drive motor M is driven in the forward direction, and in the reverse drive state in which the drive motor M is rotated in the reverse direction with respect to the forward direction for braking. Is switched to a locked state in which is locked. The drive motor M functions as a driving unit that applies a forward driving force to the vehicle in the forward rotation driving state, and functions as a braking unit that switches to a reverse driving state or a locked state during braking and applies a braking force to the vehicle.

  One of the positive terminal and the negative terminal of the drive motor M is connected to the power supply side through the switch means Tr1 made of a transistor, and to the ground side through the switch means Tr3, and the other is connected to the ground side through the switch means Tr2. The power supply side is connected to the ground side via the switch means Tr4. Then, the switch means Tr1, Tr4 is turned on and the switch means Tr2, Tr3 is turned off, so that the drive motor M is rotated forward, the switch means Tr2, Tr3 is turned on, and the switch means Tr1, Tr4 is turned off. By setting the state, the drive motor M is reversed. Further, by turning on the switch means Tr3 and Tr4 and turning off the switch means Tr1 and Tr2, the circuit of the drive motor M is closed and the drive motor M is locked. Further, by turning off all of the switch means Tr1, Tr2, Tr3, Tr4, the drive motor M becomes zero torque and enters a free rotation state.

Hereinafter, based on the flowchart shown in FIG. 4, the brake control process of the electric vehicle of the present invention will be described. Was the brake operation amount SB supplied from the brake sensor BBS? Judgment is made (step S101). When there is no supply (step S101: No), it means that the brake operation amount is zero and there is no brake operation (brake off state), so the brake control process is not executed. Accordingly, the free rotation state is maintained in a state where the drive motor M outputs drive torque for normal traveling or the drive motor M does not generate torque.
If the brake operation amount is supplied (step S101: Yes), the vehicle speed V is detected (step S103). The vehicle speed V is calculated based on the rotational speed of the drive wheel supplied from the drive wheel rotational speed sensor MRS. This step S103 constitutes a vehicle speed detecting means.

  It is determined whether or not the vehicle speed V detected in step S103 is greater than a predetermined value α (step S105). The predetermined value α is set as an index for determining whether the driver is traveling with his / her foot on the pedal or a standby state where the driver is descending from the vehicle. Examples of the standby state include a stop state where the speed is zero, a state where the driver is walking while pushing the vehicle, a straddle that is straddling the pedal, and the vehicle moves forward while kicking the ground with the foot. This includes whether the vehicle is moving backward. The maximum speed expected to be obtained in such a state can be set as the predetermined value α. Therefore, when the vehicle speed is smaller than the predetermined value α, it can be determined that the vehicle is in a standby state. The predetermined value α may be set to a speed value at which there is no fear of the vehicle falling over when the drive wheel is locked by applying a brake. Further, the vehicle control circuit EC stores the vehicle speed when the pedal starts to be started at the time of starting (when the input of the pedal torque or the pedal rotation speed is started), and the vehicle speed value at the start of the row (or The average value) may be a predetermined value α. Alternatively, the maximum value of the vehicle speed at which the vehicle moves backward when the minimum reverse torque is generated in the drive motor M may be set as the predetermined value α. This step S105 constitutes vehicle state determination means.

  When the vehicle speed V is smaller than the predetermined value α (step S105: No), it is determined that the vehicle is in a standby state. In such a case, the vehicle speed is small and is not preferable for generating reverse torque. Therefore, control for locking the rotation of the drive motor M is performed. The switch means Tr1 and Tr2 are turned off (step S107), and the switch means Tr3 and Tr4 are turned on (step S109). By such processing, the drive wheel 23f is locked by the lock of the drive motor M. A motor lock means is comprised by step S107 and step S109. After step S109, the brake control process is terminated.

  If the vehicle speed V is greater than the predetermined value α (step S105: Yes), it is determined that the vehicle is in a traveling state. In this case, it can be estimated that a large braking force is necessary, and the drive motor M is caused to output the reverse torque Tm. (Step S111). The reverse torque Tm is determined by a function of the brake operation amount SB and the vehicle speed V when the brake operation is detected. For example, it can be obtained as a proportional value [Tm = −A * SB * V] in which the reverse torque constant is defined as −A. By generating such reverse torque, a braking force corresponding to the grip amount of the brake lever 224 can be exerted. Specifically, when the brake lever 224 is grasped shallowly (or lightly) (the amount of operation is small), the braking force is small, and when deeply grasped (or grasped strongly) (the amount of operation is large). ) Increases the braking force. When the vehicle speed is low, the braking force is small, and when the vehicle speed is high, the braking force is large.

Such a calculation method of the reverse torque Tm is not limited to the above method. For example, in consideration of the driver's inertia, the weight of the driver may be further multiplied. That is, the braking force (reverse torque) may be adjusted according to the weight of the driver.
The weight of the driver can be estimated from the value of the drive torque output by the drive motor M during acceleration and the degree of change in the vehicle speed at that time. Such estimation processing of the driver's weight is executed by the vehicle control circuit EC at the time of start acceleration, and when the brake operation is detected, the calculated weight is used for calculation of the reverse torque. By processing in this way, the braking force can be controlled so that the braking force increases as the weight of the driver increases.

  The operation amount detected by the brake sensor BBS may be one or more of a lever movement amount such as a lever rotation amount, a pressure value applied to the lever, and a lever movement speed. The brake operation of the brake lever of a general bicycle adjusts the braking force by the force with which the brake is gripped. Therefore, by controlling the brake force based on the pressure value applied to the lever, the operation of a conventional bicycle is controlled. You can get closer to your senses. Step S111 constitutes a motor reverse rotation means. Moreover, a brake control means is comprised by step S101-step S111.

  As described above, after the execution of step S111, the brake control process is terminated. If no brake operation is detected (step S101: No), the drive motor M does not exert a braking action, so the drive wheels 23f are not locked even when the vehicle speed V is smaller than the predetermined value α. Therefore, if the brake lever 224 is not operated by a brake, the driver walks while pushing the vehicle in the standby state, does not step on the pedal while straddling the saddle, and moves forward or backward while kicking the ground with the foot. Driving operations such as can be performed in the same way as a general bicycle.

  With the above configuration, it is possible to perform control according to the brake operation according to various situations when driving a bicycle. For example, when a brake operation is performed for the purpose of decelerating during traveling, braking according to the speed is performed in steps S105 and S111. When the brake is operated for the purpose of fixing the vehicle at the start, or when the vehicle starts on an uphill or starts on a downhill, the wheels are locked by Step S105, Step S107, and Step S109. The vehicle is maintained in a stopped state by a brake operation. That is, when starting on an uphill, unlike the prior art document 1, the drive wheels are locked when the brake is turned on, so that the vehicle does not move backward. Further, unlike the configuration of the prior art document 2, since acceleration is not applied in starting on a downhill, acceleration beyond that intended by the driver does not occur.

In addition to the case where the rotation of the driving motor M is locked, the locking means is provided with a mechanism for fixing the driving wheel or the driven wheel by a mechanical configuration, for example, and the electric energy of the solenoid or the like is changed to a mechanical displacement amount. A configuration may be adopted in which an actuator to be converted is used to switch between the locked state and the unlocked state.
In the above description, a bicycle is taken as an example of the electric vehicle. However, the electric vehicle is not limited to a two-wheeled vehicle having front and rear wheels, but may be a three-wheeled vehicle or a four-wheeled vehicle having two front wheels and two rear wheels. Further, the drive wheels may be rear wheels instead of front wheels.

DESCRIPTION OF SYMBOLS 1 Electric vehicle 2 Car body 22 Handle 224 Brake lever 241 Saddle 23f Drive wheel 23b Drive wheel M Drive motor CU Control unit BU Battery unit GU Power generation unit

Claims (5)

A vehicle body on which the driver is placed;
A vehicle having front and rear wheels supported respectively on the front and rear of the vehicle body;
A pedal rotating unit having a crank that rotates about a rotation axis, and a pedal that is provided at the tip of the crank and that receives a pedaling force of a driver;
A motor for driving at least one of the front wheel or the rear wheel;
Braking operation means for the driver to input a braking operation;
Braking detection means for detecting a braking operation of the braking operation means;
Vehicle speed detecting means for detecting the vehicle speed of the vehicle;
An electric vehicle provided with a braking control means for braking the vehicle by controlling the rotation of the motor based on the vehicle speed detected by the vehicle speed detecting means when a braking operation by the braking detecting means is detected. The braking control means includes
Vehicle state determination means for determining whether the vehicle is in a standby state or a running state based on the vehicle speed detected by the vehicle speed detection means;
2. The electric motor according to claim 1, further comprising: a motor lock unit that sets the rotation of the motor to 0 when it is determined that the vehicle state determination unit is in a standby state and braking is detected by the brake detection unit. vehicle. The braking control means includes
The electric vehicle according to claim 2, further comprising: a motor reverse rotation unit that causes the motor to generate a torque in a reverse rotation direction when the vehicle state determination unit determines that the vehicle is in a traveling state. The electric vehicle according to claim 2 or 3, wherein the vehicle state determination means determines that the vehicle is in a standby state when the vehicle speed detected by the vehicle speed detection means is smaller than a predetermined value. The brake detection means detects a brake operation amount,
The electric vehicle according to claim 4, wherein the motor reverse rotation means determines reverse rotation torque according to a brake operation amount detected by the brake detection means.

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