JPH0124720B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an electric motor control device for a cargo handling vehicle such as a battery forklift.

Conventionally, an electric motor for driving a hydraulic pump of a cargo handling vehicle, such as a battery forklift, has been controlled by a device as shown in FIGS. In the figure, reference numeral 1 denotes an electric motor for driving a hydraulic pump, and the electric motor 1 rotates a hydraulic pump 2, which sucks and discharges hydraulic oil from a tank 3. 4 is a gate circuit for controlling the rotational speed of the electric motor 1, and a gate signal from this gate circuit 4 is input to the thyristor chopper 5. This thyristor stopper 5 controls the current passing through the electric motor 1 based on the gate signal, and controls the rotational speed of the electric motor 1. A control valve 7 is interposed between the hydraulic pump 2 and the tank 3 and the lift cylinder 6, and an engagement groove 9 is formed in the middle between the spool in the control valve 7 and the swingable control lever 8. Rod 1
Connected by 0. 11 is a potentiometer, and this potentiometer 11 is connected to the tap 1 connected to the rod 10 via a link 12.
3, and a resistor 15 supported by the vehicle body 14 of the cargo handling vehicle.
It has The voltage from the tap 13 is then applied to the gate circuit 4 as an input signal. Note that 16 is a limit switch that is turned on and off by the engaging groove 9 of the rod 10, and the contactor 17 is operated by turning on and off the limit switch 16. Further, 18 is a power source. On the other hand, although not shown, a control valve, a potentiometer, a gate circuit, and a thyristor stopper are also provided for the tilt cylinder, and the rotation speed of the electric motor 1 is controlled according to the opening degree of this control valve. has been done. Although not shown, the electric motor for driving the vehicle is also provided with a potentiometer that is linked to the amount of depression of the accelerator pedal, and the voltage from this potentiometer is applied via the gate circuit thyristor stopper. The rotational speed of the travel drive electric motor is controlled by In this way, conventionally, in order to control the lift cylinder and tilt cylinder, a potentiometer, a gate circuit, and a thyristor switch were installed corresponding to each control valve. Potentiometers, gate circuits, and thyristor switches were installed to control the motor. In addition, the rotational speed of the electric motor for driving and the electric motor for driving the hydraulic pump is controlled by the accelerator command value (see Japanese Patent Application Laid-open No. 73767/1983), or by activating the cargo handling circuit when the accelerator command value is less than a set value. A device that interrupts the running circuit (see Utility Model Application No. 110976/1983) is known. However, in such a conventional example, in which the rotational speed of the electric motor for travel and hydraulic pressure is controlled by the amount of accelerator depression (described in Japanese Patent Application Laid-open No. 53-73767), the electric motor for travel and Since the control lever must be turned off in order to switch the operation of the electric motor for driving the hydraulic pump to only the electric motor for driving the hydraulic pump, there was a problem in that the operability was poor.

On the other hand, in a system (described in Utility Model Application Publication No. 54-110976) that shuts off the traveling circuit by activating the cargo handling circuit when the accelerator command value is less than the set value, Since the circuit of the electric motor is interrupted, the electric motor for travel and the motor for driving the cargo handling pump cannot be operated at the same time. That is, it is not possible to carry out loading and unloading while applying driving force while traveling at low speeds, resulting in a problem of poor workability.

This invention was made in view of the above-mentioned problems, and includes a drive control means that controls the electric motor for driving the hydraulic pump when the accelerator pedal is depressed in one direction. The object of the present invention is to solve the above-mentioned problem by operating both the drive control means and the drive control means that control the drive electric motor when the accelerator pedal is depressed in the other direction.

Hereinafter, one embodiment of the present invention will be described based on the drawings.

First, the configuration will be explained. In Figure 3, 21
is an electric motor for driving a hydraulic pump; a hydraulic pump 22 is connected to this electric motor 21, and the hydraulic pump 22 is rotated by the electric motor 21. 23 is a tank, and 24 is a lift cylinder. The hydraulic pump 22 and tank 23
The lift cylinders 24 are connected to each other by an oil passage 25, and a control valve 26 is interposed in the oil passage 25 to control the amount of hydraulic oil discharged from the hydraulic pump 22 and supplied to the lift cylinder 24. has been done. 27 is the electric motor 2
A gate signal from this gate circuit 27 is input to a thyristor chopper 28. This thyristor stopper 28 controls the current passing through the electric motor 21 based on the gate signal, and controls the rotational speed of the electric motor 21. The gate circuit 27 and thyristor chopper 28 described above constitute a drive control means 29 as a whole. On the other hand, 30 is a gate circuit for controlling the rotational speed of the electric motor 31 for driving, and a gate signal from this gate circuit 30 is input to the thyristor chopper 32. This thyristor stopper 32 controls the current passing through the electric motor 31 based on the gate signal,
The rotation speed of the electric motor 31 is controlled. The gate circuit 30 and thyristor chopper 32 described above collectively constitute a traveling control means 33. In FIG. 4, a bracket 35 is fixed to a vehicle body 34 of a cargo handling vehicle, and a central portion of an accelerator pedal 37 is rotatably connected to this bracket 35 via a pin 36. As a result, the accelerator pedal 37 can be rotated in one direction (backward in this example) and in the other direction (forward in this example). A plurality of compression springs 38 as elastic bodies are interposed between the vehicle body 34 and the accelerator pedal 37, and these compression springs 38 hold the accelerator pedal 37 in a neutral position. 3
9 is a box attached to the vehicle body 34;
A rotating shaft 40 is rotatably supported on this box 39. A lever 41 is fixed to one end of the rotation shaft 40 protruding from the box 39, and the upper end of a transmission rod 42 is rotatably connected to the lever 41. The lower end of the transmission rod 42 is bent toward the accelerator pedal 37 and is connected to the lower surface of the other end of the accelerator pedal 37. As a result, the rotation of the accelerator pedal 37 is transmitted to the rotation shaft 40 via the transmission rod 42 and lever 41. As shown in FIGS. 5 and 6, a cam 43 is fixed to the other end of the rotating shaft 40 located inside the box 39, and a contact 45 of a micro switch 44 as an operation stopping means is fixed to this cam 43. are in contact. This micro switch 44 is fixed to the inner surface of the box 39. When the cam 43 rotates together with the rotation shaft 40, the micro switch 44 turns on and off, and when the micro switch 44 is on, the switch 46 shown in FIG.
is turned on, and when the micro switch 44 is turned off, the switch 46 is turned off. A substantially fan-shaped detection blade 47 is fixed to the other end of the rotating shaft 40, and a part of this detection blade 47 is connected to the box 3.
It is inserted into a U-shaped high frequency transmitting coil 48 fixed to the inner surface of 9. The above-mentioned high frequency transmitting coil 48 and detection blade 47 constitute a signal oscillating means 49 as a whole. As a result, when the detection blade 47 rotates together with the rotation shaft 40, the amount of electromagnetic waves generated from the high frequency transmitting coil 48 changes,
A signal corresponding to the change in the amount of electromagnetic waves is transmitted from the high frequency transmitting coil 48 to the gate circuit 27 and the switch 4.
6 to the gate circuit 30. In addition,
As can be seen from the above, the change in the amount of electromagnetic waves corresponds to the amount of rotation of the accelerator pedal 37 from the neutral position in one direction or the other direction. In addition, in FIG. 3, 50 is a power supply, and 51 is a contactor. Regarding the tilt cylinder,
Although not shown, a control valve for controlling the tilt cylinder is interposed in the middle of the oil passage 25, and the amount of hydraulic oil supplied to the tilt cylinder is controlled by this control valve. In this way, the control valve 26 for the tilt cylinder and the control valve 26 for the lift cylinder
simply controls the flow rate of hydraulic oil, and the signals input to the gate circuits 27 and 30 are sent from the accelerator pedal 37 side.

Next, the operation of one embodiment of the present invention will be explained.

When the accelerator pedal 37 is rotated in one direction from the neutral position against the compression spring 38 (depressed toward the rear), the rotation shaft 40 is rotated in the direction of arrow A via the transmission rod 42 and lever 41. As a result, the micro switch 44 is turned off by the cam 43, and the switch 46 is turned off. At this time,
The detection blade 47 rotates together with the rotation shaft 40 by an amount corresponding to the amount of rotation of the accelerator pedal 37, and the amount of electromagnetic waves generated from the high frequency transmitting coil 48 changes. Due to this change, a signal is input only to the gate circuit 27, and the gate signal is sent from the gate circuit 27 to the thyristor chopper 28. As a result, the value of the current passing through the electric motor 21 is controlled, and the rotational speed of the electric motor 21 is controlled. In this way, the rotational speed of the electric motor 21 is controlled in proportion to the amount of rotation of the accelerator pedal 37 in one direction. The flow rate of hydraulic oil discharged from a hydraulic pump 22 driven by an electric motor 21 is adjusted by a control valve 26 and then supplied to a lift cylinder 24 to operate the lift cylinder 24. In this way, when the accelerator pedal 37 is rotated in one direction, only the rotational speed of the electric motor 21 increases in proportion to the amount of rotation. As a result, the lift cylinder 24 and the tilt cylinder are controlled independently of the traveling speed of the cargo handling vehicle. on the other hand,
When the accelerator pedal 37 is rotated in the other direction (depressed forward), the rotation shaft 40 is rotated in a direction opposite to the direction of arrow A. As a result, the micro switch 44 is turned on, and the switch 46 is also turned on. At this time, due to the rotation of the detection blade 47, a signal is transmitted from the high frequency transmitting coil 48 to both gate circuits 2.
Sent on 7,30. Thyristor choppers 28 and 3 are activated by gate signals from gate circuits 27 and 30.
2 controls the rotational speeds of the electric motors 21 and 31 in proportion to the amount of rotation of the accelerator pedal 37, respectively. When the accelerator pedal 37 is rotated in the other direction in this manner, the rotational speeds of both electric motors 21 and 31 increase in proportion to the amount of rotation.

As explained above, according to the present invention, the accelerator pedal is of a double-depress type, and when the accelerator pedal is depressed in one direction, only the drive control means that controls the electric motor for driving the hydraulic pump is operated, and the accelerator pedal is depressed in one direction. When the pedal is depressed in the other direction, both the travel control means for controlling the travel electric motor and the drive control means are activated, so that traveling and cargo handling work can be facilitated by simply switching the direction in which the accelerator pedal is depressed. This makes it possible to improve operability and workability.

[Brief explanation of drawings]

FIG. 1 is a schematic circuit diagram showing a conventional electric motor drive device for a cargo handling vehicle, FIG. 2 is a side view of the vicinity of the control valve, FIG. 3 is a schematic circuit diagram showing an embodiment of the present invention, and FIG. 5 is a side view of the vicinity of the accelerator pedal, FIG. 5 is a sectional view taken along the - arrow in FIG. 4, and FIG. 6 is a sectional view taken along the - arrow in FIG. 21...Hydraulic pump drive electric motor, 29...
... Drive control means, 31 ... Electric motor for traveling, 3
3... Travel control means, 37... Accelerator pedal,
38...Elastic body (compression spring), 44...Operation stop means (micro switch), 49...Signal transmission means.

Claims (1)

[Claims] 1. An electric motor control device for a cargo handling vehicle that controls a traveling electric motor and a hydraulic pump driving electric motor of the cargo handling vehicle, which includes a traveling control means that controls the value of the current passing through the traveling electric motor, and a hydraulic pump driving electric motor. a drive control means for controlling the value of the current passing through the electric motor; an accelerator pedal connected to the body of the cargo handling vehicle and rotatable in one direction and the other from a neutral position; and an accelerator pedal for maintaining the accelerator pedal in the neutral position. an elastic body, a signal transmitting means for transmitting a signal corresponding to the amount of rotation of the accelerator pedal in one direction or the other direction with respect to the neutral position to the traveling control means and the drive control means, and the accelerator pedal rotating in one direction from the neutral position. 1. An electric motor control device for a cargo handling vehicle, comprising: an operation stop means that stops the operation of the travel control means when this occurs.