JPS6111922Y2 - - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to a braking circuit for an electric wheelchair used by a severely disabled person.

Generally, electric wheelchairs have a braking circuit that shorts the terminals of the driving motor directly or through an appropriate resistance, and the wheelchair is braked and stopped by the motor's dynamic braking. There is.

However, although a braking circuit that directly shorts the terminals of the drive motor can provide strong braking force,
The wheelchair decelerated rapidly, making it not only unstable but also dangerous. In addition, a braking circuit that short-circuits the terminals of the travel motor through a resistor allows the wheelchair to decelerate gradually, but it takes a long time from decelerating to stopping, making driving difficult.
There were inconveniences such as the inability to stop and hold the wheelchair on a slope due to insufficient braking force.

The purpose of the present invention is to eliminate the above-mentioned disadvantages.The braking circuit is composed of a transistor, a constant voltage element, and a resistor to control the generated current during braking, thereby ensuring smooth deceleration and sufficient braking. This enables effective braking.

Hereinafter, the present invention will be explained in detail based on embodiments shown in the drawings.

FIG. 1 is a diagram showing the overall configuration of a braking circuit for an electric wheelchair. 1 is a battery, 2 is a main switch, and a conversion circuit 3 is connected to the battery 1 via the main switch 2. The conversion circuit 3 converts the amount of mechanical operation of a control lever (not shown) into an electrical signal, and applies the electrical signal to a speed control circuit 7, which will be described later. 4 is a switch that operates in response to the operation of the operating lever; the normally open contact 4a of the switch 4 is connected to the main switch 2, and the normally closed contact 4b is connected to the brake circuit 5.
The contact pieces 4c are connected to respective contacts 61a and 62a of interlocking switches 61 and 62 for switching between forward and reverse movement. Each contact 61b, 62b of the interlocking switches 61, 62 is connected to the terminal 5b of the braking circuit 5, and also to one end of the battery 1 via the speed control circuit 7. Further, the contact piece 61c is connected to the contact piece 62 through the left and right running motors 8L and 8R, which are connected in parallel.
connected to c.

FIG. 2 is a diagram showing the detailed structure of the brake circuit 5. As shown in FIG. In the figure, 9 and 10 are first and second transistors, respectively. The collector of the first transistor 9 is connected to the terminal 5a through the resistor 11, the emitter is connected to the terminal 5b, and the base is connected to the resistor 12,
It is connected to the terminal 5a via the constant voltage element 13. The collector and emitter of the second transistor 10 are connected to terminals 5a and 5b, respectively, and the base is connected to the collector of the first transistor 9. A resistor 14 has a relatively small resistance value (about several ohms) and is connected in parallel to the second transistor 10 .

Next, the operation of the brake circuit configured as described above will be explained. Now, when the main switch 2 is turned on in the state shown in FIG. 1 and the operating lever (not shown) is operated, the switch 4 is activated and the contact piece 4c is
connected to a. Then, the running motors 8L, 8
R is connected to the battery 1, and by the functions of the conversion circuit 3 and the speed control circuit 7, the driving motors 8L and 8R rotate at a speed according to the amount of operation of the operating lever, and the electric wheelchair runs.

When the operation of the operating lever is released while the vehicle is running, the switch 4 returns to its original state and the contact piece 4c is connected to the contact point 4a, both terminals of the travel motors 8L and 8R are disconnected from the battery 1, and both ends 5a of the braking circuit 5 are disconnected from the battery 1. , 5b. Then, the traveling motors 8L and 8R enter a power generation state, and a voltage is applied between the terminals 5a and 5b of the braking circuit 5 in accordance with the traveling speed.

Therefore, when the running speed is high, a high voltage is applied between the terminals of the braking circuit 5, and the constant voltage element 1
3 is conductive. When the constant voltage element 13 becomes conductive, a current flows to the base of the transistor 9, turning the transistor 9 ON, and when the transistor 9 turns ON, the base and emitter of the transistor 10 are short-circuited, and the transistor 10 turns OFF. Become. Therefore, the combined resistance between the terminals 5a and 5b has a resistance value that is almost the same as that of the resistor 14, which has a small resistance value, and the traveling motors 8L and 8R are short-circuited by the resistor 14. In other words, when the running speed is high, the running motor 8L,
Since both ends of 8R are short-circuited, a gentle dynamic braking force acts. Further, when the speed decreases due to gentle dynamic braking, the voltage generated by the traveling motors 8L and 8R decreases, and the voltage applied between the terminals 5a and 5b decreases. Then, the current flowing through the constant voltage element 13 gradually decreases, and finally the current flowing through the constant voltage element 13 is cut off. Therefore, transistor 9
The voltage between the collector and emitter of
The transistor 10 is turned off, and along with this, the transistor 10 is gradually turned on, and finally turned on completely. In other words, as the traveling speed decreases, the terminals 5a, 5b
The combined resistance between transistors 10 and 10 decreases, and finally
When it is completely turned on, it is short-circuited and a strong braking force is applied.

That is, to summarize the above operation, when the vehicle is running at high speed, a gentle braking force is applied to decelerate the vehicle, and as the traveling speed decreases, the braking force increases to achieve smooth deceleration and reliable braking and stopping.

FIG. 3 shows another embodiment of the braking circuit 5.
The configuration is such that a diode 15 is additionally connected between the terminals 5a and 5b of the embodiment shown in the figure. In this embodiment, the reverse rotation of the driving motors 8L and 8R is prevented by the diode 15, and the interlocking switches 61 and 6 for switching between forward and backward movement shown in FIG.
Regardless of the input position of 2, when the wheelchair is stopped, dynamic braking is always activated in both forward and reverse directions.

As is clear from the above description, the braking circuit of the present invention is adapted to control the generated current during braking according to the running speed of the wheelchair, and is capable of smooth deceleration and sufficient braking. Furthermore, the braking circuit of the present invention has a simple configuration consisting of a constant voltage element, a transistor, and a resistor, and is easy to manufacture and maintain, and has great practical value.

[Brief explanation of the drawing]

FIG. 1 is a diagram showing the overall configuration of a wheelchair control circuit, FIG. 2 is a diagram showing an embodiment of the present invention, and FIG. 3 is a diagram showing another embodiment. Explanation of symbols, 5...braking circuit, 5a, 5b...
Terminal, 9, 10... Transistor, 11, 12...
...Resistor, 13... Constant voltage element, 14... Resistor having a relatively small resistance value, 15... Diode.

Claims (1)

[Claims for Utility Model Registration] (1) In a braking circuit that has terminals 5a and 5b, and in which the terminals 5a and 5b are connected to both ends of the traveling motor during braking, the base of the first transistor 9 is connected to the resistor 12 and Terminal 5a via constant voltage element 13
The emitter is connected to the terminal 5b, the collector is connected to the terminal 5a via the resistor 11, the collector of the second transistor 10 is connected to the terminal 5a, the emitter is connected to the terminal 5b, and the base of the first transistor 9 is connected to the terminal 5b. A resistor 14 connected to each collector and having a relatively low resistance value between the terminals 5a and 5b.
A braking circuit for an electric wheelchair characterized by a configuration in which the following are connected. (2) A braking circuit for an electric wheelchair according to claim 1, characterized in that a diode 15 is connected between the terminals 5a and 5b.