JPS6329647Y2 - - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to an electromagnetic brake actuating device used in an electric vehicle such as an electric wheelchair. It was designed to stop at

Electric vehicles are generally easier to operate than vehicles equipped with internal combustion engines. For this reason,
When automating wheelchairs for people with physical disabilities, it is common to make them electric. To take full advantage of this feature, electric wheelchairs are made so that they can move forward, backward, and turn left, right, and turn by operating a single control lever.

Because electric wheelchairs exhibit these functions,
A DC motor is attached to the left and right wheels, and a motor controller controls the forward rotation, reverse rotation, and rotation speed of the DC motor. As a braking device, instead of installing a special brake device, the power supply to the motor is stopped or the motor terminals are short-circuited to cut off the driving force, and then the power transmission loss between the motor and the wheels is used. Normally, it is stopped by

However, with this method, there is a problem in that the vehicle cannot be stopped on a slope because a large braking force cannot be obtained. In order to solve this problem, the number of rotations of the motor is detected, and when the vehicle is to be stopped, a reverse voltage is applied to the motor to stop the vehicle. However, this method requires a device to detect the rotational speed of the motor, making it complicated.

The present invention has been made in view of this point.
The present invention has a configuration for this purpose, in which an electric vehicle is equipped with an electromagnetic brake and a control lever that emits an output signal to stop driving the wheels in a neutral state, and when the neutral state of the control lever is detected, the electromagnetic a detection circuit that controls to emit an output signal that causes a brake to generate a large braking force, immediately lowers the level of this output signal, and then issues an output signal that gradually increases the braking force of the electromagnetic brake; This configuration includes a voltage control section. One embodiment of the present invention will be explained with reference to the drawings. In FIG. Sliders 4, 5
is adapted to be moved by a control lever 6 operated by the passenger. The variable resistor 2 is for controlling the left wheel, and the variable resistor 3 is for controlling the right wheel. Voltage is applied to both ends of these variable resistors 2 and 3. Sliders 4 and 5 of these variable resistors 2 and 3 are connected to two terminals 7a and 7b of a motor controller 7.
Note that the control lever 6 issues a signal to stop driving the wheels when in the neutral state.

The motor controller 7 controls motors 8 and 9 attached to wheels (not shown) based on signals received from the sliders 4 and 5.
Therefore, the motors 8 and 9 are connected to the output terminals 7c and 7d. Note that a power source is connected to this motor controller 7, but its illustration is omitted. Electromagnetic brakes 10 and 11 having a structure to be described later are attached to the motors 8 and 9, respectively, and when activated, they stop the wheels together with the motors 8 and 9.

12 is a brake actuation device. The brake actuation device 12 includes a detection circuit 13 that detects the neutral state of the control lever 6, and a voltage control section 14 that receives the output of the detection circuit 13 and controls the output voltage. The input side of the detection circuit 13 is connected to the sliders 4 and 5 of the variable resistors 2 and 3, and receives voltage depending on the position of the sliders 4 and 5, and detects the neutral position of the control lever 6 from this voltage. I'm starting to do that.

A voltage control section 14 is connected to the output side of the detection circuit 13. The voltage control section 14 includes the detection circuit 1
When receiving the output signal of 3, the electromagnetic brake 10,
11. Note that the electromagnetic brakes 10 and 11 may not be provided for each wheel as described above, but may be configured such that one brake is applied to both wheels.

FIG. 2 shows a specific example of the voltage control section 14. To explain this, 15 is an input terminal connected to the output side of the detection circuit 13, which obtains an "H" signal when the control lever 6 is in the neutral state, and obtains an "L" signal at other times. . Input terminal 1
5 is connected to a control terminal of a first analog switch 16, an input side of an inverter 17, and one end of a capacitor 18.

The output side of the inverter 17 is connected to the control terminal of the second analog switch 19. The other end of the capacitor 18 is connected to the input side of the non-inverter 20. Between the connecting end of the capacitor 18 and the non-inverter 20 and the ground, the cathode side of a diode 21 whose anode side is grounded (grounded to the vehicle body, the same applies hereinafter) and the other end of a resistor 22 whose one end is grounded are connected. There is. A control terminal of a third analog switch 23 is connected to the output side of the non-inverter 20. A fourth analog switch 24 is connected in series to the third analog switch 23 . One end of the fourth analog switch 24 is grounded. The control terminal of this fourth analog switch 24 is connected to the output side of the inverter 17 together with the control terminal of the second analog switch 19 described above. These analog switches 16, 19, 23, 24 are
They are turned on when an "H" input signal is applied to each control terminal, and turned off when an "L" input signal is applied to each control terminal.

25 is a battery which is a power source. One end of a third analog switch 23 and one end of a constant current circuit 26 are connected to the positive side of this battery 25. The other end of the battery 25 is grounded. The other end of the constant current circuit 26 is connected to one end of the first analog switch 16. The other end of the first analog switch 16 is connected to the positive side of a reference battery 28 via a parallel circuit of a second analog switch 19 and a capacitor 27. The negative side of the reference battery 28 is grounded. The reference battery 28 generates an initial voltage which will be described later.

A positive input terminal of a buffer amplifier 29 is connected to a connection point between the first analog switch 16, the second analog switch 19, and one end of the capacitor 27. A negative input terminal of this buffer amplifier 29 is connected to an output terminal. The output terminal is connected via a resistor 30 to the connection point between the third analog switch 23 and the fourth analog switch 24 and to the positive input terminal of the power amplifier 31. A negative input terminal of the power amplifier 31 is connected to an output terminal. An electromagnetic brake 10, which will be described later, is connected between the output side of the power amplifier 31 and the ground.
Eleven brake coils 32 and 33 are connected.

FIG. 3 shows an example of the electromagnetic brakes 10, 11. To explain this, numeral 34 is a brake body, and output shafts 35 of motors 8 and 9 are rotatably connected to this brake body 34 by bearings 36. A brake shoe 37 is attached to the tip of the brake body 34, and faces a brake disc 38 attached to the output shaft 35 with a gap a in between.

A protrusion 39 is provided near the tip of the output shaft 35, and a brake disc 38 is mounted inside this protrusion 39 so that it can move in the axial direction relative to the output shaft 35 but not rotate. It is being A return spring 40 is interposed between the brake disc 38 and the bearing 36 in a slightly compressed state. When the brake body 34 becomes an electromagnet by energizing the brake coils 32 and 33 buried near the tip of the brake body 35, the return spring 40 provides a repulsion direction to the brake disc 38 that is pulled by the brake body 34. It gives the power of

Next, the operation of this device configured as described above will be explained. In Fig. 1, when the electric wheelchair is in a running state, the passenger uses the control lever 6 to stop the wheelchair.
When the brake is placed in a neutral state, the detection circuit 13 of the brake actuation device 12 detects this state and outputs an "H" output signal. This output signal is given to the voltage control section 14.

The following will be explained with reference to FIGS. 2 and 4. When the input terminal 15 receives an "H" input signal (see FIG. 4), this signal turns on the first analog switch 16. At this time, inverter 1
A second analog switch 1 controlled via 7
9 is off. Since one end of the capacitor 27 is grounded via the reference battery 28, the ground potential of the capacitor 27 is maintained at a value based on the electromotive voltage of the reference battery 28.

When the first analog switch 16 is closed, a current i controlled by the constant current circuit 26 flows through the capacitor 27 to charge it. As this charging progresses, the voltage at the point increases and is eventually held at a constant value. Then, as shown in FIG. 4, when the signal input to the input terminal 15 ceases, this voltage instantly drops to its original value. Note that the reference voltage of is set higher than the ground voltage by E due to the reference battery 28.

When there is an "H" input signal at the input terminal 15, current also flows through the capacitor 18 to charge it. This charging current will flow from the capacitor 18 to the resistor 22, so from the moment the input signal is input to the input terminal 15, a time constant t determined by the capacitance of the capacitor 18 and the resistance value of the resistor 22 is applied.
Only for a period of time (for example, 50 milliseconds) does the point have a high value, as shown in FIG.

When such a high value occurs at the point, the third analog switch 23 closes and the battery 2
5 is applied to the positive input terminal of the power amplifier 31, and the brake coils 32 and 33 at this moment
The brake disc 38 is excited by a large current.
This causes friction between the brake shoe 37 and the brake shoe 37. This state is terminated by the charging of capacitor 18 progressing (eg, 50 milliseconds, as described above) and by turning off third analog switch 23.

By combining the waveforms of the points in FIG. 2 and , a voltage with a waveform as shown in FIG. 4 is obtained. The brake coils 32 and 33 are excited by the voltage of this waveform with the power amplified by the power amplifier 31, so that the brake coils 32 and 33 act strongly at first.
Immediately after that, it loosens once and then gradually increases (see FIG. 4).
In this case, when the force is initially applied and then it loosens, it is not a completely released state, and the reference battery 2
Since the electromotive voltage is increased by 8, smooth braking characteristics can be obtained. In addition, the control lever 6
deviates from the neutral state, the brake coil 32,
The applied voltage at 33 is removed.

In the embodiment described above, the voltage applied to the brake coils 32 and 33 is controlled, but the current may also be controlled. Moreover, as the electromagnetic brakes 10 and 11, brakes that generate braking force by applying voltage to the brake coils 32 and 33 are used, but they may also be brakes that reduce the braking force when voltage is applied. In this case, the voltage waveform at the point in Figure 2 is controlled as shown in Figure 4'.

Since the present invention is configured as described above, it has the advantage of being able to stop an electric vehicle smoothly and reliably with less impact by operating a single control lever, despite having a simple structure with few parts. .

[Brief explanation of the drawing]

Fig. 1 is a circuit diagram showing an outline of an embodiment of the present invention, Fig. 2 is a circuit diagram showing a specific example of the voltage control section shown in Fig. 1, and Fig. 3 is a part showing an example of an electromagnetic brake. The sectional view and FIG. 4 are waveform diagrams showing the operating state. 1...Controller, 2, 3...Variable resistor, 4,5
...Slider, 6...Control lever, 7...Motor controller, 8,9...Motor, 10,1
DESCRIPTION OF SYMBOLS 1... Electromagnetic brake, 12... Brake actuation device, 13... Detection circuit, 14... Voltage control section, 1
5... Input terminal, 16... First analog switch, 17... Inverter, 18, 27... Capacitor, 19... Second analog switch, 2
0...Non-inverter, 22...Resistor, 23
...Third analog switch, 24...Fourth analog switch, 25...Battery, 28...
Reference battery, 29... Buffer amplifier, 31... Power amplifier, 32, 33... Brake coil, 3
4... Brake body, 35... Output shaft, 37...
Brake shoe, 38... Brake disc, 4
0...Return spring.

Claims (1)

[Scope of utility model registration request] An electric vehicle is equipped with an electromagnetic brake and a control lever that emits an output signal to stop wheel drive in a neutral state, and when the neutral state of the control lever is detected, an output that instantly generates a large braking force in the electromagnetic brake. A detection circuit and a voltage control unit are provided for controlling the output signal to emit a signal, immediately lowering the level of the output signal, and then emitting an output signal that gradually increases the braking force of the electromagnetic brake. An electromagnetic brake actuation device.