JPH11150812A - Traveling and drive device for industrial vehicle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a traveling and drive device for an industrial vehicle capable of easily maintaining its traveling speed at a constant value. SOLUTION: Operating range to be inputted from an accelerator which inputs the target traveling speed of a vehicle is set with respect to three corresponding speed ranges (a low speed range, a middle speed range and a high speed range) for the maximum traveling speed of the vehicle. When the traveling speed of the vehicle reaches 70% of the operating range, the operating range of the accelerator is shifted to a higher speed range. When the traveling speed of the vehicle reaches 30% of the operating range, it is shifted to a lower speed range. A target speed is set by the operating angle and speed ranges of the accelerator. A controlling device is provided for controlling an electric motor based on the target speeds set this way. This structure enables the change in the operating angle of the accelerator to be made small for the change of the traveling speed, and thereby enables easy maintenance of the traveling speed to a constant value.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an industrial vehicle which travels by driving drive wheels by an electric motor, such as a dump truck, a wheel loader, a forklift, and a container carrier used at a cargo handling site or a construction site. The present invention relates to a driving device.

[0002]

2. Description of the Related Art A conventional driving system for an industrial vehicle will be described with reference to FIG. Drive wheels 41 for running industrial vehicles
A DC electric motor 42 is connected to the
A rectifier 43 for supplying power to 42 is provided. This rectifier 43
Is supplied from an AC generator 45 connected to the engine 44 via a conductor 46. A traveling speed detector 47 is provided on the drive shaft of the drive wheel 41, and the traveling speed is displayed on a speed meter 48 by the speed detection signal of the traveling speed detector 47.

A signal indicating the operation angle of the accelerator pedal 50 (for example, 10 to 50 °) is input to the governor 51 of the engine 44, and the speed of the vehicle is reduced by the acceleration / depression of the accelerator pedal 50. It is controlled by increasing or decreasing the voltage of the DC electric motor 42.

[0004]

However, the operation angle of the accelerator pedal 50 is only a small angle of 10 to 50 °, and a slight change in the angle appears as a large change in the traveling speed. It is nervous to work, and industrial vehicles involve other operations such as cargo handling,
There has been a problem that the workability is reduced and the feeling of fatigue of the operator is increased.

Further, in the above-mentioned traveling drive system, the brush for sending electricity to the rotor of the DC electric motor 42 wears out, so that the DC electric motor 42 needs to be periodically replaced. Since the speed of the vehicle is controlled, it is difficult to prevent tire slip in a vehicle such as a cargo handling vehicle in which the axle load and the traction force change suddenly.

Accordingly, an object of the present invention is to provide a traveling drive device for an industrial vehicle that can easily maintain a constant traveling speed and facilitate maintenance.

[0007]

According to one aspect of the present invention, there is provided a traveling drive device for driving an electric motor for traveling of an industrial vehicle, wherein a target traveling speed of the vehicle is controlled. Target command input means for inputting, traveling speed detection means for detecting the traveling speed of the vehicle, and a correspondence of the operation range inputted from the target command input means, a plurality of correspondences with respect to the range of the maximum traveling speed of the vehicle. When the traveling speed of the vehicle detected by the traveling speed detection means reaches a predetermined high speed value of the operation range, the operation range is shifted to the high speed side traveling stage. When the traveling speed of the vehicle detected by the traveling speed detection means reaches a predetermined low speed value in the operation range, the vehicle shifts to a low speed traveling stage, and by the operation input value and the traveling stage of the target command input means,
Control means for setting a target speed and driving the electric motor based on the target set speed is provided.

Here, the industrial vehicle is a dump truck,
Wheel loaders, forklifts, container carriers, etc. The target command input means is an accelerator pedal,
These include levers and rotary potentiometers that are operated by hand.

According to the above construction, the correspondence of the operation range of the target command input means is set to a plurality of traveling stages with respect to the range of the maximum traveling speed, so that the operation range of the target command input means is the maximum traveling speed. Corresponding to a part of the range, the change in the operation input value of the target command input means is smaller than the change in the traveling speed. Therefore, even if the operation input value of the target command input means is not firmly maintained, the traveling speed hardly changes, and the traveling speed can be easily maintained.

According to a second aspect of the present invention, there is provided a travel driving device for driving a travel electric motor of an industrial vehicle, wherein the travel electric motor is formed by an AC electric motor and supplies power to the AC electric motor. An inverter is provided, and the driving speed of the vehicle is controlled by controlling the torque and the number of revolutions of the AC electric motor by the inverter.

Here, the industrial vehicle is a dump truck,
Wheel loaders, forklifts, container carriers, etc. According to the above configuration, by using an AC electric motor as the traveling electric motor, the electric motor is worn like a brush of a conventional DC electric motor, and there are no parts to be replaced regularly, thereby facilitating maintenance.

[0012]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 6 is a configuration diagram of a traveling drive system of an industrial vehicle showing an embodiment of the present invention.

An AC electric motor 2 is connected to drive wheels 1 for driving an industrial vehicle.
An inverter 3 is provided to control the torque and the rotation speed of the motor 2 by controlling the primary voltage applied to the motor 2 and maintain the rotation speed of the motor 2 at a command value described later. This inverter 3
Is supplied from a brushless generator 5 connected to the engine 4 via a conductor 6. Drive wheel 1
Is provided with a traveling speed detector 7. A field current is supplied to the generator 5 from a battery 9 via a field breaker 8. Further, a braking resistor 10 that consumes regenerative braking energy during deceleration is connected to the inverter 3.

A control device 11 for outputting a command value of the rotation speed of the motor 2 to the inverter 3 is provided.
/ Reverse R switching signal, the signal of the operation angle of the accelerator pedal 13 (for example, 10 to 50 °), and the traveling speed detector 7
Running speed of the vehicle detected by the
m / hr). Further, ON signals of the traveling driving push button 14 and the traveling stop push button 15 provided in the vehicle cockpit, an engine abnormal signal from the controller 17 of the engine 4, and detection of an engine speed provided on the drive shaft of the engine 4. The engine speed signal of the generator 18 and the output voltage signal of the generator 5 from the voltage detector 19 are input to the control device 11.

The control device 11 controls the accelerator pedal 13
The operation angle (10-50 °) of the vehicle is changed to the traveling speed (0-5
0 km / hr), and outputs a command value of the rotation speed of the motor 2 to the inverter 3 to control the traveling speed of the vehicle. Further, when the control device 11 inputs an abnormal signal of the inverter 3 itself or the motor 2 from the inverter 3, the control device 11 outputs an off signal (cutoff signal) to the field breaker 8 and the contactor 6 to stop power generation, and Power supply is cut off and the vehicle is stopped to ensure safety.

FIG. 1 is an explanatory diagram of a multi-stage target control by a traveling drive device for an industrial vehicle according to the present invention. As shown in FIG. 1, the operation angle (10 to 50 °) of the accelerator pedal 13 is converted into an operation range (0 to 100%), and the operation range (0 to 100%) is changed.
100%) corresponds to the traveling speed of the vehicle (0 to 50 km / h).
r) has three stages. The first stage is in the low speed range (Fig. 1
, 0 to 14 km / hr), the second stage is in the middle speed range (5 to 3
5km / hr), the third stage is a high speed range (15-50km / h)
r), the change in speed corresponding to the change in the operation angle of the accelerator pedal 13 is reduced. The low-speed region and the medium-speed region, the medium-speed region, and the high-speed region are set such that their speed regions overlap each other.

The operation range of the accelerator pedal 13 (0 to 1)
(00%) is performed when the traveling speed increases to 70% of the speed range to the high speed side, and when the speed decreases to 30% of the speed range to the low speed side. Will be It should be noted that the shift threshold of each speed range (30%, 70
%) Can be freely changed according to the characteristics of the corresponding vehicle and the preference of the driver.

The configuration of the control device 11 will be described with reference to block diagrams of FIGS. As shown in FIG. 5, based on the voltage v of the generator 5 detected by the voltage detector 19, the generator voltage normal (voltage establishment) is detected by the comparator 21, and the overvoltage of the generator 5 is detected by the comparator 22. The predetermined speed (high speed) is detected by the comparator 23 based on the rotation speed n of the engine 4 detected by the engine rotation speed detector 18, and the operation of each of the comparators 21, 22, 23 The relays SV, OV, and HI to be driven are provided, and a relay LO that operates when the output of the comparator 23 is off (at low speed) is provided. As shown in FIG. 2, a comparator 24 is provided for detecting when the operation value x% of the accelerator pedal 13 is 0%, that is, when the accelerator pedal 13 is released. Is provided.

As shown in FIG. 4, when the engine start signal is input from the engine controller 17 and the speed of the engine 4 is low (relay LO on), the traveling operation push button 14 is turned on. An acceleration command signal is output to the engine controller 17 so as to increase the speed of the engine 4.

The forward / reverse switching handle 12 is selected to be neutral, the speed of the engine 4 is high (relay HI on), the accelerator pedal 13 is released (relay Z on), and the inverter 3 is abnormal. When no signal is input, an ON signal (make signal) is output to the field breaker 8 and when an abnormal signal is input from the inverter 3 or when the generator 5 is overvoltage (relay OV ON). Or, when an engine abnormality signal is input from the engine controller 17 or when the travel stop push button 15 is turned on, an off signal (cutoff signal) is output to the field breaker 8.

When the generator 5 reaches the rated voltage (relay SV ON), an ON signal is output to the contactor 6 and an abnormal signal is input from the inverter 3 or when the generator 5 is overvoltage ( When a signal indicating engine abnormality is input from the engine controller 17 or when the travel stop push button 15 is turned on, an off signal is output to the contactor 6.

As shown in FIG. 2, the accelerator pedal 13
Is calculated by the target speed calculators 26, 27, and 28 according to the speed ranges of the respective speed ranges, and the selected relays RY1, RY2, R of the respective speed ranges described later.
One of them is selected by Y3 to become the actual target speed, and the difference between the target speed and the traveling speed m of the vehicle detected by the traveling speed detector 7 is obtained by the subtractor 29.
A rotational speed command value in the forward direction is calculated by the PID calculator 30 based on the obtained deviation, and a reverse (-rotational speed command value) in the reverse direction is calculated by the + -inverter 31 from the rotational speed command value.
Is calculated, and is selected by the switching signal of the forward / reverse switching handle 12 and output to the inverter 3. Inverter 3
Drives the motor 2 in the forward direction of the industrial vehicle with a plus (+) rotation speed command value, and drives the motor 2 in the reverse direction with a minus (-) rotation speed command value. In addition,
When the forward / reverse switching handle 12 is selected to be neutral, the neutral selection signal is output to the inverter 3, and the inverter 3 stops free running (natural stop) according to the neutral selection signal.

The running speed m of the vehicle is 70% of the low speed range.
Speed setting value (14 km / hr * 0.7 = 10 km / h
r) The above is detected by the first comparator 32, and 70
% Speed set value ｛5 km / hr + (35-5) km / hr
* 0.7 = 26 km / hr} or more is detected by the second comparator 33, and the 30% speed set value in the high speed region {15 km / hr}
+ (50-15) km / hr * 0.3 = 26 km / h
r｝ or less is detected by the third comparator 34, and 30
% Speed set value ｛5 km / hr + (35-5) km / hr
* 0.3 = 14 km / hr｝ or less is detected by the fourth comparator 35, and relays A, B, C, and D driven by the operations of the comparators 32, 33, 34, and 35 are provided. I have.

As shown in FIG. 3, the selection relay RY1
Are set / reset by the RS flip-flop 36, at the first start, or when the medium speed range is selected (RY2 on), and the running speed m is 3 in the middle speed range.
It is set when the speed becomes equal to or less than the 0% speed set value (relay D on) (the RS flip-flop 36 is set), the low speed range is selected (RY1 on), and the traveling speed m
Is reset when the speed becomes equal to or higher than the 70% speed set value in the low speed range (relay A on).

The selected relay RY2 is set / reset by the RS flip-flop 37, the low speed region is selected (RY1 on), and the running speed m is equal to or higher than the 70% speed set value of the low speed region. (Relay A on) or when the high-speed range is selected (RY3 on)
When the running speed m becomes equal to or less than the 30% speed set value in the high speed range (relay C ON) (the RS flip-flop 37 is set), the first start or the middle speed range is selected. Cage (RY2 ON) and running speed m
Is 70% or more of the middle speed range (Relay B on) or the middle speed range is selected (RY2 on) and the traveling speed m is 30% or less of the middle speed range (Relay D ON) is reset.

The selected relay RY3 is set / reset by the RS flip-flop 38, the medium speed range is selected (RY2 on), and the running speed m is set to 70% of the medium speed range. The value is set when the value becomes equal to or greater than the value (relay B on) (the RS flip-flop 38 is set), and at the time of the first start or the high speed region is selected (RY3 on), and the traveling speed m is in the high speed region. 30% of
It is reset when the speed becomes equal to or less than the speed set value (relay C ON).

The operation of the above configuration at the time of starting the running and at the time of inverter failure will be described. [During Normal Running] When the engine 4 is started and the operator operates the travel push button 14, an acceleration command is output to the engine controller 17, and the engine controller 17 causes the engine 4 to rotate at a high speed.

When the accelerator pedal 13 is released,
When the rotation of the engine 4 becomes high in a state where the reverse handle 12 is selected to be neutral, the field breaker 8 is turned on,
The generator 5 is excited. When the output voltage of the generator 5 is established, the contact 6 is turned on and power is supplied to the inverter 3.

In this state, when forward or reverse is selected by the forward / reverse handle 12 and the accelerator pedal 13 is depressed, the traveling speed is set according to the operation angle of the accelerator pedal 13 and output to the inverter 3. Motor 2
Is driven.

At this time, by realizing the shift of the speed range, for example, in the operation range (0 to 100%) of the accelerator pedal 13 in the low speed range, the vehicle is running at 50%, 80%
When the vehicle speed rises to 70% (10 km / hr), the target speed becomes 80% of the low speed range to the middle speed range.
Is changed to Therefore, if a shift feeling is obtained and the desired speed is attained in the middle speed range, the accelerator pedal 13 may be slightly released. If the vehicle is still depressed, the target speed is changed from the medium speed range to the high speed range.

When the vehicle is returned to 20% while traveling at 50% in the operation range (0 to 100%) of the accelerator pedal 13 in the high-speed range, the target speed is reduced to 30% (26 km / hr) when the vehicle speed is reduced to 30% (26 km / hr). The speed is changed from the high speed range to 20% of the middle speed range. Therefore, if a feeling of shifting is obtained and there is a desired speed in the middle speed range, the accelerator pedal 13 may be depressed slightly. If the state is returned as it is, the target speed is changed from the medium speed range to the low speed range. [At the time of Inverter Abnormality] It is assumed that an abnormality has occurred in the inverter 3 or the motor 2, the abnormality has been detected by the inverter 3, and an abnormality signal has been output to the control device 11.

When an abnormal signal is input from the inverter 3, an off signal is output to the field breaker 8 and the contactor 6, so that the exciting current to the generator 5 is cut off, and at the same time, the power supply to the inverter 3 is cut off. The vehicle stops naturally.

In this state, while the abnormality signal of the inverter 3 is turned off, the accelerator pedal 13 is released, and the forward / reverse handle 12 is selected to be neutral, the field breaker 8 is turned on again. The generator 5 is excited. Generator 5
Is established, the contact 6 is turned on and power is supplied to the inverter 3 again.

In this state, when forward or reverse is selected by the forward / reverse handle 12 and the accelerator pedal 13 is depressed, the traveling speed is set according to the operation angle of the accelerator pedal 13 and the motor 2 is driven. The vehicle is driven.

When the output voltage of the generator 5 becomes overvoltage (relay OV ON), or when an abnormality occurs in the engine 4, an OFF signal is output to the field breaker 8 and the contactor 6 to excite the generator 5. The current is cut off, and at the same time the power supply to the inverter 3 is cut off, and the vehicle naturally stops.

As described above, when an abnormality occurs in the inverter 3 or the motor 2, it can be safely stopped, and the operation range of the accelerator pedal 13 is set to three steps with respect to the range of the maximum traveling speed. As a result, the operation range of the accelerator pedal 13 corresponds to a part of the range of the maximum traveling speed, and the slight change of the accelerator pedal 13 corresponds to the slight change of the traveling speed. The running speed does not change much even if the running speed is not firmly maintained, so that the running speed can be easily maintained.

An AC electric motor 2 is used to drive the drive wheels 1.
By using a brush, it is possible to eliminate a portion that needs to be periodically replaced like a brush of a conventional DC motor, thereby facilitating maintenance.

In the above embodiment, the accelerator pedal 13 is used as the target command input means. However, a lever operated by hand or a rotary potentiometer may be used, and similar effects can be expected by the present invention. In addition, the correspondence of the operation range of the target command input means is set to three steps with respect to the range of the maximum traveling speed, but it is not limited to three steps, but may be set to multiple steps.

[0039]

As described above, according to the present invention, the correspondence of the operation range of the target command input means is set to a plurality of travel stages with respect to the range of the maximum traveling speed, so that the target command input means is controlled. The operation range corresponds to a part of the range of the maximum traveling speed, and the change in the operation input value of the target command input means is small with respect to the change in the traveling speed, and the operation input value of the target command input means is kept firmly constant. If it is not possible, the running speed will not change much, and the running speed can be easily maintained.

Further, by using an AC electric motor as the traveling electric motor, it is possible to eliminate the need to periodically replace the brushes of the conventional DC electric motor, thereby facilitating maintenance.

[Brief description of the drawings]

FIG. 1 is an explanatory diagram of multi-stage target control by a traveling drive device of an industrial vehicle according to an embodiment of the present invention.

FIG. 2 is a block diagram of a traveling drive device of the industrial vehicle.

FIG. 3 is a block diagram of a traveling drive device of the industrial vehicle.

FIG. 4 is a block diagram of a traveling drive device of the industrial vehicle.

FIG. 5 is a block diagram of a traveling drive device of the industrial vehicle.

FIG. 6 is a configuration diagram of a traveling drive system of the industrial vehicle.

FIG. 7 is a configuration diagram of a traveling drive system of a conventional industrial vehicle.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Drive wheel 2 AC electric motor 3 Inverter 4 Engine 5 Generator 6 Conductor 7 Travel speed detector 8 Field breaker 9 Battery 10 Braking resistor 11 Control device 12 Forward / reverse switching handle 13 Accelerator pedal 14 Traveling operation push button 15 Drive stop push button 17 Engine controller 18 Engine speed detector 19 Voltage detector

 ────────────────────────────────────────────────── ─── Continuing on the front page (72) Inventor Shuzo Okayama 1-1-1, Tanabe Shinda, Kawasaki-ku, Kawasaki-shi, Kanagawa Prefecture Fuji Electric Co., Ltd.

Claims (2)

[Claims] 1. A traveling drive device for driving an electric motor for traveling of an industrial vehicle, comprising: target command input means for inputting a target traveling speed of the vehicle; and traveling speed detecting means for detecting a traveling speed of the vehicle. And setting the correspondence of the operation range input from the target command input means to a plurality of travel stages with respect to the range of the maximum travel speed of the vehicle, and setting the operation range of the target command input means to the travel speed detection. When the traveling speed of the vehicle detected by the means reaches a predetermined high speed value in the operation range, the vehicle shifts to a high speed side traveling stage, and the traveling speed of the vehicle detected by the traveling speed detection means changes to a predetermined low speed value in the operation range. Then, the vehicle shifts to a low-speed traveling stage, a target speed is set based on the operation input value of the target command input unit and the traveling stage, and control means for driving the electric motor based on the target set speed is provided. Travel drive apparatus of an industrial vehicle, characterized in that there was e. 2. A travel drive device for driving a travel electric motor of an industrial vehicle, wherein the travel electric motor is formed by an AC electric motor, and an inverter for supplying power to the AC electric motor is provided. A traveling drive device for an industrial vehicle, wherein the traveling speed control of the vehicle is performed by controlling a torque and a rotation speed of the AC electric motor.