WO2003059236A1

WO2003059236A1 - A safety wheelchair

Info

Publication number: WO2003059236A1
Application number: PCT/CN2002/000729
Authority: WO
Inventors: Susu HU
Original assignee: Jiao Yi Station
Priority date: 2001-10-26
Filing date: 2002-10-18
Publication date: 2003-07-24
Also published as: CN1344536A; CN1143666C; AU2002344515A1

Abstract

An electric wheelchair comprises a body, two rear wheel, a front wheel, at least an electric motor and a controller. In the two rear wheel and the front wheel, at least one wheel is driven by the electric motor. The safety wheelchair also comprises a decelerator which is a means consists of short-circuit connection of a conductor with a load and coils so the driving motor by the decelerator switch. When the electric wheelchair goes forward with a speed greater or less than the predetermined value, the controller gives a signal so that the switch of the decelerator turns on or off. While the switch is on, the electric motor is changed into an electric generator so that the wheelchair can automatically decelerate when goes around a turn or naturally downslide along an incline to ensure that the wheelchair can not be overturned as result of the overspeed of the turning. The load of the decelerator may be a means, which can recharge a battery so that the redundant kinetic energy of the wheelchair carrying person can be changed into electric energy recharging the battery when the wheelchair decelerates. The wheelchair has electric braking system. The wheelchair can be automatically braked at once by turning off the actuating switch of the wheelchair while running.

Description

Technical wheelchair

The invention relates to a structure of an electric wheelchair, and a safety wheelchair. Background technique

When an electric wheelchair with two rear wheels performs a circular motion with a radius of 0.8 meters, the maximum forward speed of the rear wheel on the side far from the center of the circle cannot be too large. When it is too large, for example, it exceeds 2.6 meters per second, it may fall over. Chinese patent 93201901.3 introduces the structure of an electric wheelchair, which is provided with a motor drive system, a braking system, and an auxiliary brake using an electromagnetic brake. However, when the vehicle speed is too high, it will not automatically decelerate, and the vehicle speed cannot be maintained within a safe value. There is also a four-wheel wheelchair. Each rear wheel is driven by a motor. Each motor and the rear wheel are driven by a pair of worm gears with a self-locking function. The motor can drive the rear wheels. The rear wheels cannot drive the motor. After the motor is started, the vehicle speed is determined by the speed of the motor and will not increase due to downhill. The power to the motor will be cut off and the rear wheels will stop immediately. The wheelchair is more expensive. The above two types of electric wheelchairs cannot use gravity to work when going downhill, and convert excess kinetic energy into electrical energy to charge the power source. Object of the invention

The object of the present invention is to propose a safety wheelchair, which can automatically decelerate when turning or naturally descending from a slope, and the manufacturing cost is low.

Another object of the present invention is to convert excess kinetic energy into electrical energy to charge the power source when the wheelchair is decelerating, turn off the wheelchair start switch, and automatically brake. Summary of the Invention

This safety wheelchair includes a vehicle body, two rear wheels, at least one front wheel, at least one motor and a controller. The two rear wheels are respectively installed on the rear sides of the vehicle body, and the front wheels are installed on the front of the vehicle body. At least one of the wheel and the rear wheel is driven by a motor, and it is also equipped with a speed reducer. The speed reducer is a device constituted by short-circuiting the line of the drive motor with a load-bearing conductor through the speed reducer switch.

When the forward speed of this type of safety wheelchair exceeds or is lower than a preset value, the reducer switch is turned on or off. When the power is turned on, the power supply stops supplying power to the motor. At this time, the motor becomes a generator that discharges the load. Magnetic field forces prevent the motor from rotating, limiting the forward speed of the wheelchair to a safe value. Drawing description

Figure 1 is a schematic diagram of the overall structure of such a safety wheelchair.

Figure 2 is a schematic diagram of the reducer.

3 and 4 are schematic diagrams of an electric brake device.

Figure 5 is a schematic diagram of an electric brake device used in a two-motor-driven wheelchair.

Figure 6 is a schematic diagram of the reducer when two motors are connected in series.

Fig. 7 is a schematic diagram of a reducer and an electronic steering mechanism when two motors are connected in parallel.

FIG. 8 is a schematic view of a shaft seat for fixing the rear wheel axle.

FIG. 9 is another overall structural diagram of such a safety wheelchair. Preferred embodiment

As shown in FIG. 1 and FIG. 2, this safety wheelchair includes a vehicle body 9, two rear wheels 24, at least one front wheel 20, at least one motor 1 and a controller, and the two rear wheels are respectively installed behind the vehicle body 9 On both sides, the front wheels are installed in front of the car body, and at least one of the front and rear wheels is driven by a motor. It is also equipped with a reducer whose load is connected to the coil of the drive motor via a reducer switch 2.

The reducer switch 2 can be an electronic switch or a relay switch, or a series or parallel combination of several switches. It is controlled by the controller: The electric signal or current input terminal of the switch is connected to the electric signal or current output terminal of the controller. When the forward speed of the safety wheelchair exceeds or is lower than a preset value, for example, 2.5 m / s, the controller will send a signal or current to turn the reducer switch 2 on or off.

The load of the reducer may be a resistor, a capacitor, an inductor, or other components that consume or store electrical energy. It can also be a battery charging device (a combination of a charger and a battery).

The reducer is activated when the vehicle speed exceeds 2.5 m / s. After starting, the forward resistance of the wheelchair is approximately equal to the sliding force of the passenger wheelchair on a 12.5-degree slope. From this, it can be calculated that: using a 36V power supply and a 400-watt motor (when the vehicle speed is 2.5 m / s, the The electromotive force is 30 ~ 33V). When decelerating in this way, the induced current through the motor should be controlled at 20 ~ 22 amps. So if the load used for this motor is a resistor, its resistance value should be about 1.5 ohms.

When this safety wheelchair is driven by a DC motor, the controller can use pulse width modulation to control the motor speed. The controller can include a pulse width generator (rectangular pulse generator with adjustable width), a speed sensor, a speed detector, and a rated speed. Comparators, governors, and wheelchair start switches are the same as some existing electric bicycle or electric wheelchair controllers. In addition, it includes a limit speed comparator. The working process is as follows: The speed sensor converts the motor speed into an electrical signal and sends it to the speed detector. The limit speed comparator compares the feedback signal from the speed detector with the limit speed set by it. When the vehicle speed exceeds the limit speed, it sends a signal To the pulse width generator circuit and the reducer switch 2, the pulse width generator output is zero, and the reducer switch 2 is turned on. The motor becomes a generator and starts to decelerate. When the vehicle speed is lower than the limit speed, the comparator sends a signal to make the reducer switch 2 cut off the circuit and stop the deceleration. The maximum speed of a four-wheeled wheelchair can be set to 2.5 m / s. The rated speed set by the rated speed comparator is less than the limit speed of 0.1 to 0.5 m / s. The rated speed comparator receives the signal from the speed detector. When the vehicle speed is lower than the rated speed, the signal from the rated speed comparator causes the pulse width generator to output again. The governor can use an electric knob, which changes the pulse width of the pulse width generator through the signal level and adjusts the motor speed.

In the controller of the present invention, the limit speed comparator is not limited to one, and may have two to three. Because a three-wheeled wheelchair with a distance of 0.5 meters between the two rear wheels and 0.9 meters between the front and rear wheels turns, when the turning radius of the wheelchair shield center is 0.9 meters (that is, the handlebar angle is 46 degrees), the maximum forward speed allowed by the rear wheels Cannot exceed 2 m / s. In order to prevent the wheelchair from overturning when turning, a three-wheeled wheelchair that uses only one motor to drive the right rear wheel can be designed as follows: the speed is divided into three speeds: fast, middle and slow. The speeds were set at 3 m / s, 2 m / s, and 1 m / s, respectively. When the wheelchair is driving in the fast gear, when the turning angle of the handlebar to the left is greater than 15 degrees, the shift switch is triggered to change the fast gear to the middle gear. When the corner returns to less than 15 degrees, change the middle gear to the fast gear. When the handlebar turns to the right more than 15 degrees, you need to change the fast gear to the slow gear. When the wheelchair is in the middle gear, only shift the middle gear to the slow gear when the handlebar is turned to the right. When driving in slow gear, you do not need to change gears no matter how you turn.

As shown in FIG. 3, the safety wheelchair may further include an electric brake device, which is a device formed by using a conductor to short-circuit the coil of the motor through the brake switch 3. For motors with low impedance, a current limiter can be connected in the above circuit. The function of the current limiter is to limit the current not to exceed the allowable value to avoid mechanical impact of the motor. When using dual motor drives, the current limiter limits the current per motor to less than 40 amps. The structure of the current limiter is the same as the start-up protector installed to prevent excessive current during the static start of the motor. For DC motors, the current limiter can use a variable resistor. After braking starts, as the induced electromotive force in the motor wire decreases rapidly, the voltage across the resistor decreases rapidly, and the current limiter quickly shorts the resistance step by step until the resistance becomes Zero to ensure sufficient braking current during the entire braking process. For AC motors, reactors can be used. As the voltage across the reactor drops, the reactors are short-circuited one by one.

With the electric brake device of the present invention, the motor will not overheat, because the electrical energy emitted by the motor will not exceed the work done by the external force on the motor, which is equal to the kinetic energy before the wheelchair is braked. Its size is generally not More than 500 joules. It can be calculated that the temperature of the motor wire does not rise above 4 degrees Celsius during braking. After using a current limiter with variable resistance, the thermal energy is concentrated on the current limiter, and the temperature of the motor wire does not rise above 1 degree Celsius.

The motor matched with the electric brake device of the present invention is a permanent magnet motor, and the induced electromotive force of the motor is proportional to the rotation speed. When the vehicle speed is 0.1 m / s, the induced electromotive force is still greater than 1 volt, and the motor resistance is less than 0.1 ohms. When two motors are used, the current addition is still more than 20 amps. Therefore, the above braking device can immediately stop the wheelchair on flat ground, and it can reduce the speed of the wheelchair to less than 0.1 m / s on the slope immediately (to stop, the mechanical braking device installed on the wheelchair can be used). The safety wheelchair is a slow car. In case of failure of the electric brake device, it is too late to use the mechanical brake device to brake.

The brake switch 3 in FIG. 3 may be a mechanical switch or other switches controlled by an electric signal or current.

The brake switch 4 in Fig. 4 is an electronic switch. Controlled by a wheelchair start switch. Wheelchair start switches can be push-button. When the wheelchair start switch is turned on, it sends out an electrical signal, which is directly or indirectly sent to the brake switch 4, and the brake switch 4 cuts off the circuit. When the wheelchair start switch is turned off, an electric signal is sent to the brake switch again, and the brake switch turns on the circuit, thereby realizing automatic braking. The manual switch 5 is used for automatic one-handed switching. When the manual switch 5 is turned off, the wheelchair can be pushed forward by human power.

As shown in Figure 5, the two rear wheels of this safety wheelchair can be driven by a motor 1, 10, respectively. The controller is divided into two parts. The left controller controls the left motor, and the right controller controls the right motor. Right controller. In the figure, 2, 12 are reducer switches, and 4 and 14 are brake switches controlled by the wheelchair start switch. It is also possible to use two current limiters, which are respectively installed in two motors, so that they can function as start-up protectors during static start.

As shown in FIG. 6, the two rear wheels of the safety wheelchair are each driven by a motor. When the reducer load is a device for charging the battery, the two motors 1 and 10 can be connected in series and then connected to the charger. The electromotive force in the closed circuit after the series is the sum of the electromotive forces of the two motors. The charger of this circuit can charge the battery after the voltage is reduced, or it can use no series voltage transformer to control the output current of the charger to about 11 amps by using a series resistor or pulse width modulation method. When the charger detects that the electric power in the battery power is sufficient, it sends an electric signal to the transfer switch 11, the charger stops working, and the electric current converts the electric energy into thermal energy through the resistor 15. As long as one of the limit speed comparators in the left and right controllers in the figure detects that the vehicle speed exceeds the pole speed, it sends signals to the reducer switches 2 and 12, and two pulse width generators in the left and right controllers. The circuit stops the pulse width generator and the reducer switches 2 and 12 are connected to the circuit to start deceleration. When the vehicle speed is lower than the limit speed, the comparator sends a signal again to cut off the reducer circuit. To handle two The signals from each of the limit speed comparators can be designed as two switches connected in parallel to each other, or a switch capable of logically processing two signals.

The circuit in Figure 6 is mainly used in a wheelchair driven by a motor with two rear wheels each using a mechanical steering mechanism. The mechanical steering mechanism turns by controlling the deflection of the front wheels. The four-wheeled wheelchair uses a mechanical steering mechanism with an application number of 01105514.6. When the front wheel deflection angle is constant, the turning radius of the wheelchair is determined. At this time, as long as the speed of one rear wheel is too fast, the other rear wheel must be too fast, so it is better to reduce the speed of both motors at the same time. Since the four-wheeled wheelchair's centroid turning radius is 0.8 meters, the maximum forward speed allowed by the rear wheels is 2.6 meters / second, so the maximum speed of the four-wheeled wheelchair is set to 2.5 meters / second, as long as the steering mechanism ensures that the turning radius is not less than 0.8 meters. , The wheelchair will not fall over due to turning.

A three-wheeled wheelchair using a mechanical steering mechanism can also connect two motors in parallel and use a controller to control the mains current (the sum of the two motor currents). Such a controller is equivalent to combining the pulse width generators of the left and right controllers in FIG. 6 into one, while retaining the respective speed sensors, speed detectors, rated speed comparators, and limit speed comparators of the left and right controllers. .

When the two rear wheels are driven by a motor, and the front wheels are universal wheels, an electronic steering mechanism can be used. The current electronic steering mechanism makes the wheelchair turn by the controller changing the speed or direction of rotation of the motor on one side. The wheelchair of the present invention enables the electronic steering mechanism to steer through not only the controller but also a speed reducer, thereby saving power.

As shown in Figure 7, the two motors of this safety wheelchair can also be connected in parallel to the charger. When the steering handle of the electronic steering mechanism is deflected to the left, the left governor 18 of the left controller is driven to work. The level of its output signal decreases as the steering handle angle increases. The lower the signal level, the lower the motor speed. . Due to inertia, due to the drive from the other side of the motor, or because the reducer switches 2, 12, and 13 have been connected to the circuit, the motor has no driving current, causing the left rear wheel to fail to slow down as required. At this time, the left steering switch 16 Turn on the circuit. The steering load starts to decelerate the left motor. The left steering switch 16 does not open the circuit until the requirements are met. When the steering handle is turned to the right, the right governor 19 is operated, and the steering load is controlled by the right steering switches 17, 37. The wheelchair start switch (button type) can be mounted on the top of the steering handle.

As for the circuit that the electronic steering mechanism controls the left and right steering switches according to the above requirements, there can be various designs. For example, when the motor current is large (when climbing a hill), the steering is completed only by the governors of the left and right controllers; when the current is zero (when downhill), the steering is performed only by the steering load; when the current is not large , Steer first through the governor and then through the steering load.

The electronic steering mechanism is designed to have the following functions: When the wheelchair is moving fast, the speed of the left or right motor can be reduced by half (when the wheelchair is traveling at a speed of 1.8 meters per second, the turning radius is not limited); When the switch is not activated, turn the steering handle and the wheelchair will rotate in place.

The charger in Figure 7 needs to convert DC power to AC power, boost it, and then rectify it. If it is driven by an AC motor, the battery current is supplied to the motor after AC-DC conversion, so that the current can be directly boosted in the charger. The charger is equipped with a current detector. Once there is a motor or a reducer switch that cannot conduct current due to a fault, the charger's current output is reduced by half. At the same time, an electrical signal is sent to the switch 33 to turn the switch 33 off Circuit. When current is induced in both motors, the switch 33 reconnects the circuit. The current detector can also be replaced by a relay.

As shown in FIG. 8, when an outer rotor motor (a stator fixed on the rear wheel shaft and a rotor fixed to the hub) is installed on the two rear wheel shafts of the wheelchair, the rear wheel shaft can be installed in the round hole 7 of the shaft seat 6, and the shaft seat 6 Fixed on the car body 9. The shaft seat has a through hole 8 with the center line and the circular hole 7 at an angle of 80 to 90 degrees with each other. The shortest distance between the centerlines of the two holes is less than the sum of the radii of the two holes. A pin with a slanted surface is inserted from the hole 8 and squeezes against a flat surface formed on the rear wheel axle to tighten the rear wheel axle. This structure can make the stator of the outer rotor motor bear a large braking force when braking.

In Figures 1 and 9, 9 is the body, 20 is the front wheel, 21 is the controller, 22 is the power source, 23 is the rear wheel axle, 24 is the rear wheel, 25 is the front fork, 26 is the front tube, and 27 is the front fork. Standpipe, 28 is the handlebar, 29 is the controller panel, 30 is the manual brake device, 31 is the back seat, and 32 is the steering handle.

Claims

Rights request

1. A safety wheelchair comprising a vehicle body (9), two rear wheels (24), at least one front wheel (20), at least one motor (1) and a controller, and the two rear wheels are respectively installed on the vehicle body (9) On both sides of the rear, the front wheels are installed in front of the car body. At least one of the front and rear wheels is driven by a motor. It is characterized in that it is also equipped with a reducer, which is passed by a conductor with a load. The reducer switch (2) is a device formed by short-circuiting the line of the drive motor.

2. The safety wheelchair according to claim 1, wherein the speed reducer switch (2) is an electronic switch, and the electronic switch is controlled by a controller.

3. The safety wheelchair according to claim 2, wherein the load of the speed reducer is a device for charging the battery.

4. The safety wheelchair according to any one of claims 1 to 3, wherein the controller includes a pulse width generator, a speed sensor, a speed detector, a rated speed comparator, a governor, and a wheelchair Start switch and limit speed comparator.

5. The safety wheelchair according to claim 4, further comprising an electric brake device, wherein the electric brake device is a device configured by using a conductor to short-circuit the coil of the driving motor through a brake switch.

6. The safety wheelchair according to claim 5, wherein the conductor for short-circuiting the coil of the driving motor is connected with a current limiter.

7. The safety wheelchair according to claim 6, characterized in that the brake switch (4) is an electronic switch and is controlled by the wheelchair start switch.

8. The safety wheelchair according to claim 7, wherein each of the two rear wheels of the wheelchair is driven by a motor, and the two motors are connected in series and then connected to a charger in series.

9. The safety wheelchair according to claim 8, wherein the two motors are connected in parallel and then connected to the charger.

10. The safety wheelchair according to claim 9, characterized in that the motor of the rear wheel is an outer rotor motor, the rear wheel axle is installed in the circular hole (7) of the axle seat (6), and the axle seat (6) is fixed to the vehicle body (9), the shaft seat has a through hole (8) with the center line and the circular hole (7) at an angle of 80 to 90 degrees with each other, and the shortest distance between the center lines of the two holes is less than these two The sum of the radii of the holes, a pin with a bevel is inserted from the hole (8), and squeezes against the plane opened on the rear wheel axle to fasten the rear wheel axle.