JP4056297B2 - Driving power control device for electric transport vehicle - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a traveling power control device for an electric transport vehicle provided with a number of independently steerable wheels, and particularly to prevention of engine overload.
[0002]
[Prior art]
For example, at a steelworks, a heavy-duty transport vehicle having a number of independently steerable wheels is used to transport heavy objects such as coils and large steel materials on the premises.
As shown in FIG. 1, this heavy goods transport vehicle has a flat loading platform 1 over its entire length, and includes a driver's seat 2 at the front end and the rear end. A generator 7 and a hydraulic unit 8 are provided at the bottom of the loading platform 1 in the center, and an engine 6 for driving them is mounted. Reference numeral 9 denotes a central control panel.
[0003]
Each wheel 3 is a double wheel and is attached to the frame via an arm 4. The wheels 3 are each provided with a steering actuator 16 that is driven by hydraulic pressure for steering, and the electric traveling motor 5 is attached to almost half of the wheels 3. The cab 2 is provided with an accelerator for instructing the traveling speed and a handle for steering the wheel 3. The accelerator sends an output signal proportional to the amount of depression to the traveling driver 15. The operation amount of the steering wheel is transmitted to the central control panel 9, and the steering angle of each wheel 3 is calculated to operate each steering actuator 16.
[0004]
This transport vehicle can change the height of the loading platform 1 by rotating the arm 4 connected to the wheel 3 (not shown) but has a leg portion on which a heavy object is placed. The loading platform can be lowered into the pallet, and the loading platform can be raised and carried. Further, since the driver's seat 2 is located at the front end and the rear end, the conveyance work can be performed without making a U-turn, and furthermore, each wheel 3 can be steered independently. Rows, traverses, spin turns, etc. can also be performed.
[0005]
[Problems to be solved by the invention]
The engine mounted on the electric transport vehicle as described above does not have a sufficient margin for the expected load because of space and economy. Therefore, the engine is often used near the maximum output, and is likely to be overloaded.
[0006]
The driving load of the engine during driving is largely composed of driving of the driving motor and driving of the steering actuator. When the accelerator is fully depressed, the engine can output up to the maximum output.
In addition, the steering load when steering is quite large due to the fact that each wheel is a compound wheel, and it is up to about 20% of the maximum engine output, but it is common to reduce the vehicle speed when driving on a curve. Therefore, there is usually no shortage of engine output.
[0007]
However, when driving on a curved road and entering a straight road, it is often done by fully depressing the accelerator while returning the steering wheel. In this case, the wheels remaining in the curved road are steered sequentially. The steering load is added. If the steering load is above a certain level, the engine is overloaded, causing the problem that the engine speed decreases and the output voltage of the generator decreases.
[0008]
Accordingly, the present invention is the electric transporting vehicle, and its object is to provide a travel power control apparatus that not the engine is overloaded be steered in a state in which depresses the maximum accelerator.
[0009]
[Means for Solving the Problems]
In order to achieve the above object, the present invention adopts the following means. In other words, an engine that drives a generator and a hydraulic pump is mounted, an electric travel motor and a hydraulic actuator for steering are provided on each of a plurality of wheels, and a steering wheel and an accelerator for commanding a travel speed are provided in a cab. defined in the running power controller for the electric transport vehicle, the steering detector for detecting a steering angle of the rotation detector and the handle of the operation amount or the wheel for detecting the rotational speed of the engine is provided, the maximum operating at engine rotation speed of an accelerator when lowered amount or maximum engine, the output of the travel motor when it is expected to decrease in the engine rotational speed at the maximum operation of the accelerator steering load increases on the basis of the steering signal of the small steering detector than the specified amount It is characterized by being limited to a certain percentage of output.
[0010]
The present invention prevents overloading of an engine of an electric transport vehicle having a large number of wheels provided with an electric travel motor and a hydraulic actuator for steering, and is applied to a travel driver that controls the travel motor under certain conditions. The command is limited to a certain percentage of the maximum engine output (rated output).
[0011]
In this invention, the restriction command to the traveling driver is set to the steering signal of the steering detector even when the engine speed decrease is within the specified amount, in addition to when the engine speed decrease amount is within the specified amount. This is when the steering load is expected to increase .
The specified amount of decrease in engine speed may be a limit value in a range where there is no problem in the output of the generator such as frequency and voltage.
[0012]
The engine is overloaded, for example, when the accelerator is fully depressed while returning the steering wheel when entering a straight run from a curve run, and a steering load exceeding a certain level is applied while running near the maximum output. When
Here, the steering detector indicates a steering angle detector that detects a steering angle provided on a steering shaft of a wheel or a detector that detects an operation amount of a steering wheel.
[0013]
Since the steering of each wheel has a time difference (deviation) from the operation of the steering wheel, specifically, the relationship between the magnitude of the deviation and the steering load is obtained in advance, and the steering is performed as described in claim 2. If the detector is a steering angle detector that detects the steering angle of the steering wheel and the steering angle of the wheel, the control is simplified by calculating the magnitude of the deviation between the command angle and the steering angle of each wheel. Can be.
[0014]
Since the steering load differs depending on the number of wheels 3, whether it is a single wheel or multiple wheels, and whether the steering actuator is a cylinder or a hydraulic motor, it is desirable to determine the relationship between the deviation and the steering load by actually measuring each vehicle. Moreover, since a deviation changes for every wheel, it should just judge with the average value of the deviation of all the wheels.
[0015]
A certain ratio of the engine maximum output to be commanded to the driving driver may be determined by the magnitude of the steering load. However, since the engine maximum output varies depending on the use state of the engine, it is generally 60 to the rated output of the engine. Select 80%.
Note that the maximum engine output can be increased by providing steps such as large, medium, and small for the amount of decrease in engine speed and the amount of deviation in the steering angle, and changing the limit value commanded to the driving driver step by step accordingly. Can be used in the vicinity.
[0016]
According to a third aspect of the present invention, the steering detector is used as a steering wheel operating angle detector, and the steering load is expected to increase when the steering wheel operating speed calculated from the operating angle detected by the steering angle detector is high. You may do it.
When the operation speed of the steering wheel is fast, the amount of oil supplied to the steering actuator increases, so the load on the hydraulic pump increases and the steering load increases. In this case, compared with the case of claim 2, the apparatus is simple and can be predicted at an early stage.
[0017]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
The configuration of the electric transport vehicle is the same as that described with reference to FIG. 1, and FIG. 2 is a plan view.
[0018]
This transport vehicle includes a driver's cab 2 at the front end and the rear end, and is provided with five double wheels 3 each on the left and right. Each wheel 3 is provided with a steering actuator 16, and a traveling motor 5 is provided on the wheel 3 in the second row from the front and the second row from the rear. Here, the steering actuator 16 uses a hydraulic cylinder.
[0019]
An engine 6 to which a generator 7 is directly connected is mounted near the center of the vehicle, and a traveling driver 15 for driving each traveling motor 5 is provided nearby.
A hydraulic unit 8 and a central control panel 9 for operating the steering actuator 16 are mounted. The hydraulic unit 8 is a unit in which a hydraulic pump, a control valve, an oil tank, and the like are combined.
[0020]
The engine 6 is provided with a rotation detector 11 for detecting the rotation speed of its output shaft, and a steering angle detector 12 as a steering detector is provided at the center of the steering shaft of each wheel 3. Yes.
The driver's cab is provided with a steering wheel 17 for steering and an accelerator 14 for converting the amount of depression into an electrical signal and instructing the traveling driver 15. The steering wheel 17 has an operating angle for detecting an operating angle as a steering detector. A detector 13 is provided.
[0021]
The front and rear cabs 2 are the same and can be run and steered in the same way from either. The engine 6 is also used for power for raising and lowering the loading platform 1 and driving of compressors and other auxiliary machines.
Next, the traveling power control device for this transport vehicle will be described with reference to the block diagram shown in FIG. 3 (the embodiment of the invention of claim 2).
[0022]
A control device 20 that performs driving power control of the engine that is performed during traveling is provided in the central control panel 9, and includes an input unit 21, a calculation unit 22, a comparison determination unit 23, and a storage unit 24.
The input unit 21 takes in signals from the sensor unit, that is, the rotation detector 11, the steering angle detector 12 of each wheel, the operation angle detector 13 of the handle 17, and the accelerator 14, and converts them into signals that can be easily processed by the calculation unit 22. And output.
[0023]
The calculation unit 22 calculates how much the value detected by the rotation detector 11 is lower than the initial value, and calculates the deviation between the value from the steering angle detector 12 and the value from the operation angle detector 13. Calculate. Further, a command value to the traveling driver 15 is calculated from the depression amount of the accelerator 14.
[0024]
The comparison / determination unit 23 compares the calculation result of the calculation unit 22 with the specified value set and input in advance in the storage unit, and instructs the traveling driver 15 to limit the driving power if applicable.
Next, the operation of the driving power control will be described with reference to the flowchart shown in FIG.
[0025]
When the engine of the transport vehicle is operating, signals from the rotation detector 11, the steering angle detector 12, the operation angle detector 13, and the accelerator 14 are input to the input unit 21.
The engine rotates at the rated speed, and this value is stored in the storage unit 24.
When it is detected in step 100 that the signal from the accelerator 14 is maximum, the traveling driver 15 is commanded to set the upper limit H of the traveling power to the rated maximum output of the engine (step 110), and the process proceeds to step 120.
[0026]
In step 120, the difference between the signal from the rotation detector 11 and the set value (stored in the storage unit 24) (a reduction amount of the engine speed) is calculated, and the comparison / determination unit 23 compares the difference with the specified amount K1. If it is larger than the specified amount K1, the routine proceeds to step 125, where the traveling driver 15 is commanded to set the upper limit L of the traveling power to 60% of the rated maximum output (H) of the engine.
[0027]
If it is smaller than the prescribed amount K1, the routine proceeds to step 130, where it is determined whether it is larger than the prescribed amount K2 (a value smaller than K1). If larger, the routine proceeds to step 135, where the upper limit L of the driving power is set to the rated maximum output of the engine. The driving driver 15 is commanded to be 75% of (H). If it is smaller than the prescribed amount K2, the process proceeds to step 140. The prescribed amounts K1 and K2 are determined from the amount of decrease in the rotational speed with respect to the engine load measured in advance.
[0028]
When the handle 17 is operated on a curved road or the like, a signal to that effect is sent from the operation angle detector 13, and the central control unit 9 calculates the required steering angle of each wheel and feeds oil to each steering actuator. The switching valve is activated. When the wheel 3 is steered, the rudder angle detector 12 detects the amount. Since the oil supply to the steering actuator 16 is delayed in time, the values from the operation angle detector 13 and the steering angle detector 12 can be different.
[0029]
In step 140, when the deviation is larger than M1, the traveling driver 15 is commanded to set the upper limit L of the traveling power to 60% of the rated maximum output (H) of the engine 6 (step 145).
If the deviation is smaller than M1, the routine proceeds to step 150, where it is determined whether the deviation is larger than M2 (a value smaller than M1). If larger, the routine proceeds to step 155, where the upper limit L of the driving power is set to the rated maximum output (H ) To the driving driver 15 so as to be 75%. The deviations M1 and M2 are determined from the relationship between the actually measured deviation and the steering load.
[0030]
Thus, for example, when the accelerator is fully depressed while returning the steered handle at the stage of moving from a curved road to a straight road, when the engine speed decreases by a specified amount K1 or K2 , The upper limit L of travel power is limited. Further, when the decrease in the engine speed is smaller than the prescribed amount K2, when the steering angle deviation becomes M1 or M2, the upper limit L of the traveling power is limited, and engine overload can be prevented.
[0031]
Next, another embodiment (Claim 3) will be described with reference to FIGS. FIG. 5 is a block diagram showing the overall configuration of this embodiment. The difference from the above embodiment is that there is no steering angle detector 12 for each wheel.
That is, the input unit 21 takes in the signals from the rotation detector 11, the operation angle detector 13 of the handle 17, and the accelerator 14.
[0032]
The calculation unit 22 calculates how much the value detected by the engine rotation detector 11 has decreased with respect to the set number of revolutions, and calculates the steering wheel operation speed (angle / angle) from the output value of the operation angle detector 13. Second).
Next, the operation of the driving power control will be described with reference to the flowchart shown in FIG.
The flow from step 100 to step 135 is the same as that in FIG.
[0033]
When the accelerator 14 is fully depressed and the engine speed decreases by a specified amount K1 or K2 , the upper limit L of the driving power is limited, but the decrease in engine speed is smaller than the specified amount K2. Advances to step 160.
When the handle 17 is operated, a signal to that effect is sent from the operation angle detector 13, and how much the angle of the rotation axis of the handle changes in a predetermined time (steering operation speed) is calculated. If this value is larger than the preset specified speed N1, the travel driver 15 is commanded to set the upper limit L of the travel power to 60% of the rated maximum output (H) of the engine (step 165).
[0034]
When the speed is smaller than the specified speed N1, the process proceeds to step 170, where it is determined whether the speed is larger than the specified speed N2 (a value smaller than the specified speed N1), and when larger, the process proceeds to step 175, and the upper limit L of the driving power is set to the rated maximum output of the engine. The driving driver 15 is commanded to be 75% of (H).
[0035]
This embodiment is based on the fact that when the steering speed is high, the supply amount to the steering actuator is large, and therefore it is possible to expect that the steering load will increase. Since the steering load is predicted by the steering operation signal, the accuracy is lower than in the above embodiment, but it can be known long before the actual steering load is applied, and the control system can be simplified. The prescribed speeds N1 and N2 are determined from the relationship between the steering speed and the steering load that are measured in advance.
[0036]
【The invention's effect】
As described above, the traveling power control device for an electric guided vehicle according to the present invention includes a rotation detector that detects the number of revolutions of the engine and a steering detector that detects the operation amount of the steering wheel or the steering angle of the wheel, when operating at engine speed has decreased a defined amount, or, when it is expected to decrease in the engine rotational speed at the maximum operation of the accelerator steering load increases on the basis of the steering signal of the small steering detector than the specified amount Since the output of the traveling motor is limited to a certain ratio of the maximum engine output, it is possible to prevent the engine from being overloaded. Also, only the rotation detector attached to the engine is newly added to perform this driving power control, and the steering detector used for the steering control can be used as it is. The present invention can also be applied to this.
[Brief description of the drawings]
FIG. 1 is a side view of an electric transport vehicle to which an embodiment of the present invention is applied.
FIG. 2 is a plan view of the same.
FIG. 3 is a block diagram of the control device 20;
FIG. 4 is a flowchart of the power control.
FIG. 5 is a block diagram of a control device 20 according to another embodiment.
FIG. 6 is a flowchart of the power control.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 ... Loading platform 2 ... Cab 3 ... Wheel 4 ... Arm 5 ... Traveling motor 6 ... Engine 7 ... Generator 8 ... Hydraulic unit 9 ... Central controller 11 ... Rotation detector 12 ... Steering angle detector 13 ... Operation angle detector DESCRIPTION OF SYMBOLS 14 ... Accelerator 15 ... Traveling driver 16 ... Steering actuator 17 ... Handle 20 ... Control apparatus 21 ... Input part 22 ... Calculation part 23 ... Comparison determination part 24 ... Memory | storage part

Claims (3)

Equipped with a generator and an engine that drives a hydraulic pump, an electric travel motor and a steering hydraulic actuator are provided on each of the wheels, and the driver's cab is equipped with a steering handle and an accelerator for commanding the travel speed. in running power control system of the car, a steering detector for detecting a steering angle of the operation amount or wheel rotation detector and the handle for detecting the rotational speed of the engine is provided, the maximum operating at engine speed is defined amount reduction of accelerator when, or a decrease in engine rotational speed at the maximum operation of the accelerator is when the steering load is expected to be larger based on the steering signal of the small steering detector than the specified amount, the output of the drive motor of the maximum engine output A traveling power control device for an electric guided vehicle characterized by being limited to a certain ratio. When the steering detector is a steering angle detector that detects the steering angle of a wheel and a steering angle of a wheel, and the deviation between the command angle detected by the steering angle detector and the steering angle detected by the steering angle detector is large The driving power control apparatus for an electric guided vehicle according to claim 1 , wherein a steering load is predicted to increase . 2. The steering load is expected to increase when a steering wheel operating speed calculated from an operating angle detected by the operating angle detector is high . A traveling power control device for an electric transport vehicle.

Images