JP2002095112A - Travel drive apparatus for industrial vehicle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a travel drive apparatus for a traveling vehicle which can prevent a vehicle from stopping when an acceleration pedal is stepped second time. SOLUTION: This travel drive apparatus has a traveling motor fed with a power by a generator connected to an engine, an inverter 3 which is fed with a power by the generator and drives the motor according to a revolution- torque characteristic curve when the voltage of the generator is normal, an angle sensor 21 which detects the operation angle of an acceleration pedal to which the operation value of the motor is inputted, and a controller 6 which limits further the change of a torque limit value corresponding to the motor revolution when the state of the operation value of the acceleration pedal is changed from a decreasing state to an increasing state. With such a constitution, when the acceleration pedal is stepped second time, the sudden increase of the load of the generator can be avoided, so that a trouble of terminal voltage drop of the generator is prevented, the inverter 3 is prevented from stopping, and the vehicle is prevented from stopping.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a driving device for an industrial vehicle.

[0002]

2. Description of the Related Art In an industrial vehicle (for example, a container carrier or a traveling vehicle), a generator is driven by driving a diesel engine, and an electric motor connected to wheels is used by using electric power generated by the generator. 2. Description of the Related Art A traveling drive device called a diesel-electric system has been developed which drives a vehicle by driving.

[0003] Fig. 3 is a block diagram of a traveling drive device of a conventional industrial vehicle using the diesel-electric traveling drive device. In FIG. 3, reference numeral 1 denotes an induction motor (an example of an electric motor) in which the rotation shaft is connected to the shaft of each of the left and right rear wheels (or front wheels) 2. Further, an inverter (an example of a traveling drive unit) 3 for driving each of the motors 1 is provided.
The motor 1 is further provided with a rotation speed detector (rotation speed detector) 5 for detecting the rotation speed of the motor 1. Each inverter 3 controls the speed of the motor 1 according to a rotation speed command value and a torque limit value of the motor 1 input from a control device 6 described later. Inverter 3
Monitors the power supply voltage as a protection function. When the power supply voltage becomes lower than a predetermined voltage, the operation is stopped (tripped) and the motor 1 is stopped.

In FIG. 3, reference numeral 11 denotes a diesel engine (an example of an engine serving as a driving source for a plurality of operations). A rotating shaft of the engine 11 has a generator 12, a bucket, a fork, a clamp, and the like mounted on a vehicle. Each shaft such as a hydraulic pump 13 for supplying pressure oil to the hydraulically driven cargo handling device 7 is connected. When the engine 11 rotates, electric power is generated in the generator 12, and the hydraulic pump 13 supplies the cargo to the cargo handling device 7. Pressure oil is supplied. Also diesel engine 11
Is rotated at 1800 rpm to obtain a 60 Hz alternating current.

The generator 12 has its field current controlled by a generator voltage regulator (AVR) 14 so that the generated voltage is constant. The power generated by the generator 12 is Power is supplied to the two inverters 3 and the motor 1 via the power supply 15, and also to other electric devices of the vehicle such as the control device 6 and an operation monitor (not shown).
In FIG. 1, reference numeral 18 denotes a battery for starting the engine 11, the generator 12, and the control device 6.

Reference numeral 20 denotes an accelerator pedal (or an operation lever corresponding to the accelerator pedal). The depression angle of the accelerator pedal 20 is detected by an angle detector 21 and the operation angle (the operation lever corresponding to the accelerator pedal or the accelerator pedal) is detected. Example of lever operation amount;
A detection signal of 50 ° / 0 to 100%) is output to the control device 6, and the control device 6 rotates the motor 1 in accordance with the operation angle of the accelerator pedal corresponding to the inputted depression amount of the accelerator pedal 20. A number command value is calculated, and the calculated rotation speed command value of the motor 1 and a torque limit value corresponding to the motor rotation speed are output to the inverter 3 to perform speed control (with torque limit). Further, since the output of the engine 11 is limited, the load of the cargo handling device is detected, and the output of the traveling device is limited.

FIG. 4 shows a rotation speed-torque characteristic curve of the motor 1 set in the inverter 3. This rotation speed-
The torque characteristic curve is obtained by setting an effective traveling power obtained by subtracting the power other than the traveling power from the output of the engine 11 by the efficiency of each part as a rotation speed-torque characteristic curve. The rotation speed region is set to a constant high torque (constant torque region), and in a region beyond the low rotation speed region, the torque is set to decrease according to the constant output. Thereby, the output of the engine 11 can be effectively used for driving the traveling motor.

The operation of the above configuration will be described. engine
When the engine 11 is started, the engine 11 is rotated at a constant rotation speed of 1800 rpm, whereby the hydraulic pump 13 is driven, and the generator 12 starts generating electricity. Also AVR14
Thus, the generated voltage is controlled to be constant. The field current of the generator 12 is supplied from the battery 18 at the time of startup, and is supplied from its own generated current after startup.

When the accelerator pedal 20 is depressed and its operation angle is detected by the angle detector 21 and is input to the control device 6, a rotational speed command value of the traveling motor 1 corresponding to the operation angle is obtained. 3 is output. That is, the rotation speed-torque characteristic curve shown in FIG. 4 is affected by the operation angle of the accelerator pedal 20, is limited by the torque corresponding to the motor speed, and the output of the engine 11 can be used effectively for driving the traveling motor.

Each inverter 3 controls the speed of the motor 1 in accordance with the input rotation speed command value, the torque limit value, and the set rotation speed-torque characteristic curve, and sets an intersection between the rotation speed-torque characteristic curve and the load curve. The driving force of the vehicle is controlled. At this time, the necessary active power is supplied from the generator 12, the vehicle is gradually accelerated from the stopped state, and the generator
12 increases the power according to the smooth acceleration state. As a result, the engine speed decreases due to the relationship with the required load of the engine 11, and the voltage of the generator 12 does not decrease.

[0011]

However, once the accelerator pedal 20 is loosened from the running or accelerating state of the vehicle, the generator 12 becomes unloaded, and when the accelerator pedal 20 is depressed again, the motor 1 instantaneously reaches the maximum output. If the load (current) increases suddenly, the engine 11 does not follow, the engine speed decreases, the generator voltage decreases, and the inverter 3 trips due to its protection function. And the vehicle stops.

[0012] In addition, there is a possibility that troubles may occur in other electric devices supplied with power from the generator 12 due to a decrease in the generator voltage. Also, when the load on the generator 12 increases rapidly, the load on the engine 11 connected to the generator 12 increases rapidly, and the engine 11 operates in an overload region and consumes a large amount of fuel. There was a problem of doing.

SUMMARY OF THE INVENTION It is therefore an object of the present invention to provide a driving device for a diesel-electric running vehicle which can prevent the vehicle from stopping when the accelerator pedal is depressed again and can improve fuel efficiency.

[0014]

According to one aspect of the present invention, an engine serving as a driving source for a plurality of operations and a generator connected to the engine are provided. A driving device for an industrial vehicle capable of performing a plurality of operations, comprising a driving electric motor connected to wheels, and an accelerator pedal for inputting an operation amount of the electric motor or corresponding to the accelerator pedal. Control means for outputting a rotational speed command value of the electric motor and a torque limit value according to the rotational speed of the electric motor in accordance with an operation amount of the accelerator pedal or a lever corresponding to the accelerator pedal; When the generator voltage is normal, the electric motor is driven in accordance with the electric motor rotation speed command value and the torque limit value input from the control means. The driving means comprises: a driving drive means, the control means, when the operation amount of the accelerator pedal or a lever corresponding to this accelerator pedal increases from a reduced state, increases the torque limit value according to the motor speed. It is characterized by further restricting the change.

According to the above configuration, when the operation amount of the accelerator pedal or a lever corresponding to the accelerator pedal increases from a reduced state to an increased amount, a change in the torque limit value according to the motor speed is further limited. This prevents a sudden increase in the load on the generator, thereby preventing a drop in the generator voltage, and preventing a situation in which the vehicle drive stops due to a stop of the traveling drive means due to an abnormal generator voltage. Is done.

According to a second aspect of the present invention, in the first aspect of the present invention, the control means changes the operation amount of the accelerator pedal or a lever corresponding to the accelerator pedal from a decreasing state to an increasing state. Then, the motor speed is increased, the torque limit value is increased to a predetermined ratio of the target torque limit value according to the motor speed, and then gradually increased toward the target torque limit value. It is.

According to the above configuration, the torque limit value is increased to a predetermined ratio of the target torque limit value according to the motor speed, and then gradually increased toward the target torque limit value, so that the motor output is reduced. Abrupt changes are prevented.

According to a third aspect of the present invention, there is provided the first or second aspect of the present invention, wherein a detecting means for detecting whether or not the vehicle is running is provided, and the control means controls the vehicle by the detecting means. Only when it is detected that the vehicle is traveling, a change in the torque limit value according to the motor speed is further restricted.

According to the above configuration, the change in the torque limit value is further limited only when the vehicle is running, and the change in the torque limit value is not limited when accelerating from a stopped state. The acceleration performance during acceleration is not affected.

[0020]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a block diagram of a control device of a traveling drive device of an industrial vehicle according to an embodiment of the present invention. The configuration of the traveling drive device of the industrial vehicle according to the embodiment of the present invention is the same as the configuration of the conventional example shown in FIG. 3 except for the configuration of the control device described below, and the description is omitted.

The control device (an example of control means) 6 includes a
As shown in the figure, a rotation speed command conversion unit 31 that converts the operation angle detected by the angle detector 21 of the accelerator pedal 20 into a target rotation speed command value of the traveling motor 1,
Differentiating the operation angle detected by the angle detector 21 of
A differentiator 32 for detecting the operation direction of the accelerator pedal 20; and a depression detection unit for turning on the output signal a when the operation direction of the accelerator pedal 20 detected by the differentiator 32 is plus (+), that is, in the depression direction. 33, a looseness detecting unit 34 for turning on the output signal b when the operation direction of the accelerator pedal 20 detected by the differentiator 32 is minus (-), that is, in a loosening direction, and a rotation attached to the traveling motor 1. Based on the rotation speed of the rear wheel 2 (traveling motor 1) detected by the inverter 3 based on the output of the speed detector 5, it is determined whether the vehicle is traveling, for example, at a rotation speed corresponding to 3 km / h per hour. , A running detector 35 for turning on the output signal c, and the rear wheel 2 detected by the inverter 3.
A torque limiter 30 that forms a torque limit value corresponding to the rotation speed of the (traveling motor 1) by a preset rotation speed-torque characteristic curve, and a change in the target torque limit value output from the torque limiter 30 A torque change limiting unit 36 for limiting (to be described in detail later), a timer 37 for turning on the output signal d after a predetermined time from when the output signal a of the depression detection unit 33 is turned on, Set when the output signal c is on and the output signal b of the loosening detector 34 is on, and reset when the output signal d of the timer 37 is on or the output signal c of the traveling detector 35 is off. The 1RS flip-flop 38 is set when the output signal e of the first RS flip-flop 38 is on and the output signal a of the depression detecting section 33 is on, and the output signal b of the loosening detecting section 34 is On The second RS flip-flop 39, which is reset when the output signal c of the traveling detector 35 is turned off, and the switching relay 40, which is excited when the output signal f of the second RS flip-flop 39 is turned on, When the switching relay 40 is excited, that is, when the contact of the relay 40 is turned on, the output torque limit value whose change is limited by the torque change limiting unit 36 is output to the inverter 3, and the switching relay 40 is When not energized, i.e. relay
When the contact 40 is off, the target torque limit value output from the torque limiter 30 is directly output to the inverter 3 as the output torque limit value.

FIG. 2A shows an example of the structure of the torque change limiting section 36. The torque change limiting unit 36 is a torque limiting unit.
The target torque limit value output from the set value α (0 <α
<100%) (Multiplier 41 for multiplying by one example of a predetermined ratio)
And a subtractor 42 for subtracting the torque limit value calculated by the multiplier 41 from the target torque limit value output from the torque limiter 30, and the change rate of the torque limit value output from the subtracter 42 Rate changer 43, which outputs the torque limit value calculated by the multiplier 41 and the torque limit value output from the rate-of-change limiter 43, and outputs the output as the output torque limit value. It is composed of a container 42. The set value α can be freely set.

With the configuration of the torque change limiting section 36, as shown in FIG. 2B, a predetermined percentage of the torque limit value calculated by the multiplier 41 (.alpha. Is output, and then the remaining (8) of the target torque limit value obtained by the subtractor 42 is output.
0%) is added by the change rate limiter 43 while keeping the change constant, and thus gradually increases toward the target torque limit value.

The operation of the above configuration will be described. In the initial state, the output signals e and f of the first and second RS flip-flops 38 and 39 of the control device 6 are off. When the engine 11 is started, the engine 11
It is rotated at a constant rotation speed of rpm, whereby the hydraulic pump 13 is driven, and the generator 12 starts generating electricity.
The generated voltage is controlled to be constant by the AVR 14. The field current of the generator 12 is supplied from the battery 18 at the time of startup, and is supplied from its own generated current after startup. [Acceleration from vehicle stop state] When the accelerator pedal 20 is depressed and the operation angle is detected by the angle detector 21 in the idling state (vehicle stop), the target rotation speed of the traveling motor 1 corresponding to the operation angle is obtained. The command value is obtained in the rotation speed command converter 31.

At this time, since the output signals e and f of the first and second RS flip-flops 38 and 39 are both off, the switching relay 40 is not energized and the contact of the relay 40 is off. The target torque limit value output from the torque limiter 30 is directly output to the torque inverter 3 as an output torque limit value.

Each inverter 3 controls the rotation of the motor 1 in accordance with the input rotation speed command value, output torque limit value, and rotation speed-torque characteristic curve of a preset torque performance curve, and thus the rotation speed-torque characteristic. The driving force (running speed) of the vehicle is controlled at the intersection of the curve and the load curve. At this time, the necessary power is supplied from the generator 12, the vehicle is gradually accelerated from the stopped state, and the generator 12 increases the torque according to the smooth acceleration state. There is no problem in acceleration performance.

The output signal c of the running detector 35 of the control device 6 is turned on when the speed of the vehicle exceeds a certain speed. [Deceleration from acceleration state (during running)] When the depression of the accelerator pedal 20 is loosened, the output signal b of the looseness detecting unit 34 is turned on, and the output signal c of the running detecting unit 35 is turned on. The 1R-S flip-flop 38 is set and the output signal e is turned on. At this time, since the output signal c of the depression detection unit 33 is off, the output signal of the second RS flip-flop 39 remains off, so that the switching relay
40 is de-energized and the relay 40 contacts are off,
The target torque limit value output from the torque limiter 30 is directly output to the inverter 3 as an output torque limit value.

The running speed of the vehicle is controlled by the inverter 3 based on the rotation speed command value output from the rotation speed command converter 31, and the vehicle is decelerated. When the accelerator pedal 20 is no longer depressed and the operation angle “0” is detected by the angle detector 21, the rotation speed command value is “0”, that is, a no-load command value is output, and the traveling motor 1 has no load. And the generator 12 has no load. [Acceleration from deceleration state] When the accelerator pedal 20 is depressed again, that is, when the operation angle is increased from a reduced state, the output signal a of the depression detection unit 35 is turned on, and the first RS is performed. Since the output signal e of the flip-flop 38 is on, the second RS flip-flop 39
Is set, the output signal f is turned on, the switching relay 40 is excited, the contact of the relay 40 is turned on, and the torque limit value whose change is limited by the torque change limiting unit 36 is output to the inverter 3 as the output torque limit value. Is done.

Therefore, at the time of stepping on again, the rotation speed command value is increased to the target rotation speed command value corresponding to the operation angle (operation amount). At that time, the output torque limit value is increased to a predetermined ratio, and thereafter gradually increased toward the target torque limit value (the torque limit value output from the torque limiter 30).

The running speed of the vehicle is controlled by the inverter 3 according to the torque limit value of which the change is limited by the torque change limiting unit 36, and the vehicle gradually accelerates. At this time,
By controlling the torque of the motor 1 in the inverter 3 with the gradually increasing torque limit value, the generator 12
The load current of the generator 12 is prevented from sharply increasing, so that the terminal voltage of the generator 12 is prevented from dropping, and the inverter 3 detects the low voltage and stops operating (trips).
A situation in which the vehicle stops can be prevented.

When the stepping is continued for a predetermined time, the second RS flip-flop 39 is output by the output signal d of the timer 37.
Is reset. [Stopping of the vehicle] When the depression of the accelerator pedal 20 is loosened, the output signal b of the looseness detection unit 34 is turned on, and the output signal c of the traveling detection unit 35 is turned on.
The S flip-flop 38 is set and the output signal e is turned on. At the same time, the second RS flip-flop 39 is reset, and the output signal of the second RS flip-flop 39 is turned off. Therefore, the switching relay 40 is de-energized and the relay
Since the contact 40 is turned off, the target torque limit value output from the torque limiter 30 is directly output to the inverter 3 as the output torque limit value.

When the accelerator pedal 20 is completely depressed and the operation angle "0" is detected by the angle detector 21, the rotation speed command value is "0", that is, a no-load command value is output, and the traveling motor is driven. 1 is controlled to a no-load state, the motor 1 stops, and the vehicle stops. Further, the generator 12 has no load.

When the speed of the vehicle becomes slower than a certain speed, the output signal c of the running detector 35 of the control device 6 is turned off, the first RS flip-flop 38 is reset, and the output signal e is turned off. Return to the initial state.

As described above, at the time of re-stepping, the change in the torque limit value according to the motor speed is limited and gradually increased to the target torque limit value (the torque limit value output from the torque limit unit 30). As a result, it is possible to prevent the load current of the generator 12 from suddenly increasing, thereby preventing the generator voltage from decreasing, and causing the inverter 3 to detect a low voltage, trip, and stop the vehicle. It is possible to prevent a decrease in the operating rate of the vehicle. Further, trouble of other electric devices due to the low voltage of the generator 12 can be avoided.

Further, since it is possible to prevent a sudden increase in the load of the engine 11 connected to the generator 12, it is possible to prevent the engine 11 from operating in an overload region and consuming a large amount of fuel. Can be prevented.

In the present embodiment, the engine 11 is a diesel engine, but it goes without saying that a gasoline engine may be used.

[0037]

As described above, according to the present invention, when the operation amount of the accelerator pedal or a lever corresponding to the accelerator pedal increases from a decreasing state to an increasing amount, the torque limit value according to the motor speed is increased. Limits the change of the load, thereby preventing a sudden increase in the load of the generator, thereby preventing the generator voltage from dropping. Can be prevented.

[Brief description of the drawings]

FIG. 1 is a control block diagram of a control device for an industrial vehicle according to an embodiment of the present invention.

FIG. 2 is a block diagram of a torque change limiting unit of the control device for the industrial vehicle and a characteristic diagram thereof.

FIG. 3 is an electric control block diagram of the industrial vehicle.

FIG. 4 is a rotation speed-torque characteristic curve of a motor of an industrial vehicle.

[Description of Signs] 1 Motor 2 Wheel 3 Inverter 5 Rotation speed detector 6 Control device 7 Cargo handling device 11 Engine 11A Engine actuator 12 Brushless generator 13 Hydraulic pump 14 Voltage regulator (AVR) 15 Conductor 18 Battery 20 Accelerator pedal 21 Accelerator pedal angle detector

 ────────────────────────────────────────────────── ─── Continuing from the front page (72) Inventor Hiroyuki Yokoyama 1-15-10 Kyomachibori, Nishi-ku, Osaka-shi, Osaka F-term in TCM Corporation (reference) 3F333 CA11 CA21 FA32 FD06 FD07 5H115 PA12 PG04 PG05 PI16 PU26 PV10 QE01 QE04 QE08 QI23 TB01 TO04 TO21

Claims (3)

[Claims] An engine serving as a driving source for a plurality of operations;
A traveling drive device for an industrial vehicle capable of performing the plurality of operations, comprising a generator connected to the engine and a traveling electric motor coupled to wheels, wherein an operation amount of the electric motor is input. An accelerator pedal or a lever corresponding to the accelerator pedal, and a rotational speed command value of the electric motor according to an operation amount of the accelerator pedal or a lever corresponding to the accelerator pedal, and a torque limit according to a motor rotational speed of the electric motor. A control means for outputting a value, and a drive for driving the electric motor in accordance with a rotation speed command value and a torque limit value of the electric motor input from the control means when the generator voltage is normal and the generator voltage is normal. Driving means, wherein the control means reduces the operation amount of the accelerator pedal or a lever corresponding to the accelerator pedal. The driving device for an industrial vehicle further increases a change in a torque limit value according to the motor rotation speed when an increase from a running state occurs. The control means increases the motor rotation speed when the operation amount of the accelerator pedal or a lever corresponding to the accelerator pedal increases from a decreasing state, and changes the torque limit value to the motor rotation speed. The travel drive device for an industrial vehicle according to claim 1, wherein the target torque limit value is increased to a predetermined ratio in accordance with the target torque limit value, and then gradually increased toward the target torque limit value. 3. A detecting means for detecting whether the vehicle is running is provided. The control means is configured to control the torque limit value according to the motor speed only when the detecting means detects that the vehicle is running. 2. The method according to claim 1, wherein a change is restricted.
A driving device for an industrial vehicle according to claim 2.