JPS6039301A - Safety circuit for electric railcar - Google Patents

Abstract

PURPOSE:To enhance the safety of an electric railcar by switching to a forward direction and simultaneously braking at the maximum when the railcar contacts an obstacle during reverse traveling and forward moving the railcar at a slow speed after stopping. CONSTITUTION:When a railcar contacts an obstacle during reverse traveling so that a safety switch 3 is operated, a thyristor SCR is conducted, a transistor TR2 is interrupted, and a reverse contactor coil R is deenergized. Further, a transistor TR4 and hence TR1 is conducted, and a forward contactor coil F is energized. Further, an output equivalent to the maximum accelerator output is applied to an oscillator 21, thereby performing the maximum plugging braking. When the railcar is stopped and subsequently forward moved, the conduction rate of the output voltage of the oscillator 21 is suppressed to the minimum conduction rate by a conduction rate detector 24, and the railcar is moved forward at the minimum speed.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Application of the Invention] The present invention relates to a safety circuit for an electric vehicle, and particularly to an electric vehicle safety circuit suitable for protecting a driver when the electric vehicle hits an obstacle.

[Background of the invention]

As a safety device for electric cars, for example, the Japanese Patent Publication No. 51-2704
There is Publication No. 4.

To explain the safety circuit of an electric pallet truck as an example of a conventional electric vehicle safety circuit, Fig. 1 is a schematic external perspective view of an electric pallet truck, in which the driver rides on step 1 and moves it by operating the handle post 2. However, there is a safety switch 3 of the safety circuit at the tip. Figure 2 (a
) is also a side view during operation; forward and reverse are performed in this form, but if there is an obstacle such as a wall behind the driver while reversing, there is a risk of the driver getting caught, so at this time the driver All you have to do is stop the vehicle, but the driver may become upset and continue to reverse the vehicle. For this reason, there is a safety switch 3 in the safety circuit at the tip of the handlebar post 2, and when this safety switch 3 is turned on when the vehicle hits an obstacle while moving backward, the switch is forcibly switched from reverse to forward. to protect the driver. Figure 2(b)
2 is a side view of the driver being caught in the rear obstacle 4 during reverse operation. At this time, the driver is caught in the rear obstacle 4 and is pressing the safety switch 3 at the tip of the handlebar post 2 with his chest. The condition is shown. However, in such a conventional electric vehicle safety circuit, when the safety switch 3 is operated, the key continues to move forward for a certain period of time without the driver stopping the operation, so there is a risk of being run over if there is a person in front. In addition, the driver's operation had the disadvantage that, for safety reasons, the vehicle was forced to move forward even though the vehicle was in reverse, and the vehicle continued to operate in the opposite direction to the driver's will.

[Purpose of the invention]

SUMMARY OF THE INVENTION An object of the present invention is to eliminate the above-mentioned drawbacks of the prior art and provide an electric vehicle safety circuit with improved safety.

[Summary of the invention]

The present invention switches the vehicle from reverse to forward when an obstacle sensor such as a safety switch is activated when the vehicle hits an obstacle while reversing, and during braking, the maximum plugging is applied even if the accelerator output is small. Control the vehicle to stop it quickly, and once the vehicle has stopped, move it forward at the minimum speed, then apply the accelerator.

This is an electric car safety circuit that resets by opening the circuit.

[Embodiments of the invention]

Embodiments of the present invention will be described below with reference to FIGS. 3 and 4. FIG. 3 is a circuit diagram showing an embodiment of the electric vehicle safety circuit according to the present invention. In FIG. 3, a positive terminal 6 of a battery 5 is connected to an armature 1 of an electric motor 9 of an electric vehicle via a fuse 8.
0 to the common contact 13 of the forward contactor 12 and the common contact 17 of the reverse contactor 16, and the common contact 15 of the forward contactor 12 and the common contact 19 of the reverse contactor 16 are connected to the field of the Connected to both ends of the magnetic coil 11, connected from the common contact 14 of the forward contactor 12 and the common contact 18 of the backward contactor 16 to the negative terminal 7 of the batch (batch) via the main transistor 20, and plugged in parallel with the armature 9. The main circuit of the electric vehicle is constructed by connecting the diode D2 and connecting the 7-lead wheel diode D1 in parallel with the connection circuit of the armature 9 and the forward and reverse contactors 14 and 16. One control circuit connects forward switch FSW through fuse f to iode D3 and reverse switch SW.
forward contactor coil F via diode D4.
is connected from the forward switch FSW to the transistor T1 and from the reverse contactor coil to the transistor TR2, and from the forward switch FSW to the base of the transistor TRI and the reverse switch RS through a series circuit of a diode D5, a resistor I, and a Zener diode ZDI. W is connected to the base of the transistor TR2 through a series circuit of a diode D6, a resistor D2, and a Zener diode ZD2, and a safety switch is connected from the anode of the diode D4 (through a series circuit of an obstacle sensor 3, a diode D16, and a resistor R4). is connected to the gate of the thyristor SC hole, and connected to the anode of the thyristor SCR via the resistor R2 and the diode D7.Furthermore, the emitter of the transistor TR4 is connected via the constant voltage circuit 23 that supplies a constant voltage from the fuse f to the control circuit. The base of the transistor TR4 is connected to the anode of the diode D9 through the resistor R8 and the diode D8, and the collector of the transistor TR4 is connected to the Zener diode ZDI through the diode D12 and the resistor R3.
The accelerator circuit 22 is connected to the input of the oscillation circuit 21 via the diode D14, and the output of the oscillation circuit 22 is connected to the input of the oscillation circuit 21 via the resistor RIO and the diode D13. further connected to the base of the main transistor 20
The collector of yX is connected to the negative input of the operational amplifier OF through the conductivity detection circuit 24, and the output of the operational amplifier OP is connected to the input of the oscillation circuit 21 through the diode D15, and the constant voltage circuit 23 to the positive input of the operational amplifier OP via the resistor R11, as well as a neutral circuit 25, resistors R5, R, 6, 7. 9.几10゜R11, R12, 几13.几14.几15
, capacitors CI, C2, diodes DIO, Dll,
It is configured by connecting a transistor TRa.

Next, FIG. 4 is a partial time chart of FIG.

To explain the operation of the configuration shown in FIG. 4 with reference to FIG. 3, first, in the case of forward operation, when the forward switch FSW is turned on,
Diode D5, resistor R1, and Zener diode ZDI
The transistor TRI becomes conductive through the forward contactor coil F, thereby energizing the forward contactor coil F.
is input (indicated by the wavy line in the figure). When the accelerator (not shown) is operated, the output of the accelerator circuit 22 increases and is input to the oscillation circuit 21 via the diode D14, the main transistor 20 becomes conductive, and the electric motor 9 is energized to perform forward power running.

In addition, in the case of reverse operation, when the reverse switch Sw is turned on at time to in FIG. The reverse contactor 16 is turned on at time io in FIG. 4. When the accelerator is operated, as the output of the accelerator circuit 22 increases as shown in FIG. The current of the electric motor 9 is increased as shown in FIG. 4, and reverse power running is performed. Next, during reverse power driving, at time t1 in Fig. 4, the driver hit an obstacle and the situation changed to 7.
When the safety switch (obstacle sensor) 3 operates and is turned on, the reverse switch R8W is turned on because the vehicle is moving in reverse, and when the safety switch 3 is turned on in this state, the thyristor 8CR is turned on via the diode D16 and the resistor R4.
A voltage is applied to the gate of the thyristor SCR, and the thyristor SCR becomes conductive. Then, the base current of the transistor Tll,2 is drawn through the diodes D7 and D9, and as a result, the transistor TR2 becomes non-conductive, and therefore the reverse contactor coil R becomes non-energized, and the reverse contactor 16 becomes non-conductive.
is opened (indicated by a solid line in the figure). Also, transistor T
The base current of R,4 is connected to resistor R8 and diodes D8 and D9.
and flows through the thyristor SC hole to the transistor TR4.
becomes conductive, thereby making the transistor TRI conductive through the diode D12 and the resistor R3, thereby energizing the forward contactor coil F and turning on the forward contactor 12, ie, switching from reverse to forward. Furthermore, even if the output from the accelerator circuit 22 is very small, a maximum output equivalent to the accelerator maximum output is forcibly applied to the input of the oscillation circuit 21 via the resistor RIO and the diode D13, regardless of the accelerator output, during braking. performs maximum plugging control. In addition, FIG. 4 shows the oscillation circuit 21 at this time.
The maximum input (indicated by a broken line), the output voltage of the oscillation circuit 21, the current of the motor 9, etc. are shown. Then, the maximum braking force is applied and the vehicle immediately stops at time t2 in FIG. 4, the braking is completed, and the vehicle continues to move forward, and the conduction rate of the main transistor 20 increases accordingly. This is detected by the conduction rate detection circuit 24 to detect that braking has ended and power running has started. Then, the operational amplifier OP operates to suppress the conduction rate of the output voltage of the oscillation circuit 21 to the minimum conduction rate, and therefore the conduction rate of the main transistor 20 to the minimum conduction rate as shown in FIG. In this way, the electric current of the electric motor 9 is minimized and the vehicle is powered forward at the lowest speed, but then the series is reset by releasing the accelerator. Note that a description of the operations of other circuit parts will be omitted.

As described above, according to this embodiment, when the reverse switch is turned on and the safety switch is activated by hitting an obstacle during reverse driving, the thyristor SCR becomes conductive and switches from the reverse contactor to the forward contactor. During braking, the maximum input is given to the oscillation circuit 21 regardless of the accelerator output to perform maximum plugging control, and when the vehicle quickly stops and continues to move forward, the main transistor is activated by the operation of the duty ratio detection circuit 24. 200 The current flow rate is controlled to the minimum so that the electric car moves forward at a very slow speed to better protect the driver when the electric car hits an obstacle. It is possible to improve the safety of

〔Effect of the invention〕

As explained above, according to the electric vehicle safety circuit of the present invention,
When the vehicle hits an obstacle while reversing, the vehicle turns forward.
As soon as the vehicle is changed, maximum braking is applied to quickly stop the vehicle, and after stopping, the vehicle is moved forward at a very slow speed, which not only better protects the driver when it hits an obstacle, but also prevents the vehicle from moving forward after moving forward. This also has other effects, such as improving vehicle safety for people entering the vehicle.

[Brief explanation of drawings]

Figure 1 is a schematic external perspective view of an electric pallet truck as an example of an electric vehicle, Figure 2 (a) is a side view during operation, and Figure 2 (b) is a similar example of an electric pallet truck hitting an obstacle during reverse operation. FIG. 3 is a circuit diagram showing an embodiment of the electric vehicle safety circuit according to the present invention, and FIG. 4 is a partial time chart of FIG. 3. l...Step, 2...Handle post, 3...
Safety switch, 4... Obstacle, 5... Battery, 9... Electric motor, 10... Armature, 11... Field coil, 12... Contactor for forward movement, 16... Reverse movement contactor, 20...main transistor, 21...
Oscillation circuit, 22... Accelerator circuit, 23... Constant voltage circuit, 24... Conductivity detection circuit, F... Forward contactor coil, 几... Reverse contactor coil, FS
W...Forward switch, R8W...Reverse switch, TR1, TR2, TR3...Each transistor, 8C
1'L...Cyrisk, OP...1st Lo3 / /

Claims (1)

[Claims] 1. An obstacle sensor that operates when the electric vehicle hits an obstacle, a means for switching the electric vehicle from reverse to forward when the obstacle sensor is activated while the electric vehicle is traveling in reverse, and a switch for switching the electric vehicle from reverse to forward. An electric vehicle safety circuit comprising means for performing predetermined maximum plugging control during braking, and means for detecting a state in which braking is completed and transition to forward power running occurs and performs a predetermined low-speed forward operation.