JPH0315571B2 - - Google Patents

Description

[Detailed Description of the Invention] Technical Field The present invention relates to a travel control device for a cargo handling vehicle, and more specifically, it is equipped with a prime mover that drives drive wheels and drives a cargo handling hydraulic pump through a continuously variable transmission. The present invention relates to a travel control device that controls the traveling speed of a cargo handling vehicle by controlling the gear ratio of a continuously variable transmission.

Conventionally, some cargo handling vehicles equipped with cargo handling equipment, such as forklifts and shovel loaders, have a single engine that drives the drive wheels and drives the cargo handling hydraulic pump via a continuously variable transmission. . This type of cargo handling vehicle has a continuously variable transmission with a torque converter or a hydrostatic continuously variable transmission.

In the case of a torque converter vehicle, when carrying out cargo handling work while traveling at low speeds, the rotation speed of the cargo handling hydraulic pump must be increased, so it is necessary to press the accelerator pedal to rev the engine. At this time, as the rotational speed increases, the vehicle speed increases. Therefore, the vehicle speed was adjusted by operating the inching pedal to prevent the vehicle speed from increasing. Therefore, cargo handling operations while the vehicle is running are troublesome and require advanced techniques, and it is extremely difficult to carry out cargo handling operations while compensating for fluctuations in vehicle speed caused by cargo handling operations.

In addition, in a cargo handling vehicle equipped with a hydrostatic continuously variable transmission, the engine is revved similarly to the torque converter vehicle, and the gear ratio is lowered by operating the swash plate operation pedal to maintain a constant vehicle speed, or the engine is used for driving or cargo handling. No matter what, I always left it blowing and adjusted the vehicle speed with the swash plate operation pedal. However, in this case as well, it is very difficult to perform cargo handling operations while compensating for fluctuations in vehicle speed caused by cargo handling operations.Moreover, since the engine is blown regardless of driving or cargo handling operations, noise and fuel consumption are reduced. There was a problem.

The present invention has been made to solve the above problems, and its purpose is to eliminate fluctuations in vehicle speed based on cargo handling operations without requiring any advanced operating techniques when carrying out cargo handling operations while driving. It is an object of the present invention to provide a travel control device for a cargo handling vehicle that can be made very small and that can improve noise and fuel efficiency.

In order to achieve the above object, the present invention provides a cargo handling vehicle equipped with a cargo handling device, in which a prime mover drives a cargo handling hydraulic pump of the cargo handling device, and the prime mover drives a continuously variable transmission. a calculation means for calculating the amount of change in vehicle speed based on the operation of the cargo handling operation device during traveling; and the calculation means for calculating the gear ratio of the continuously variable transmission for compensating for fluctuations in vehicle speed based on the operation of the cargo handling operation device. The gist of the present invention is a speed control device for a cargo handling vehicle, which comprises a means for calculating based on the amount of change, and a control means for controlling the gear ratio of a continuously variable transmission based on the calculated gear ratio.

That is, the gist of the present invention is to prevent the vehicle speed from changing even when it is necessary to increase the rotational speed of the cargo handling hydraulic pump, that is, to increase the rotational speed of the prime mover during cargo handling operations. Generally, if the gear ratio does not change by increasing the rotational speed of the prime mover, the vehicle speed will increase regardless of the amount of operation of the travel pedal. Therefore, the amount of change in vehicle speed based on this cargo handling operation is calculated, and the gear ratio of the continuously variable transmission is changed according to the calculated amount of change in vehicle speed to compensate for the fluctuation in vehicle speed due to cargo handling operation while driving. . In other words, since the vehicle speed can be changed by adjusting the gear ratio of the continuously variable transmission, conversely, the vehicle speed can be maintained constant by changing the gear ratio based on fluctuations in vehicle speed. The vehicle speed is maintained at a level based on the amount of operation of the device. Therefore, if at least the vehicle speed before the cargo handling operation (or the vehicle speed based on the operation amount of the travel control device) and the amount of change in the vehicle speed after the cargo handling operation are known, the control amount of the continuously variable transmission can be determined. The gear ratio of the continuously variable transmission is controlled by the control amount.

Furthermore, the present invention automatically controls the gear ratio of the transmission when carrying out cargo handling operations while the vehicle is running, thereby eliminating the need for sophisticated operations to maintain a constant vehicle speed and reducing noise and fuel consumption. It has the advantage of improving.

Next, preferred embodiments embodying the present invention will be described below with reference to the drawings.

First Embodiment The first embodiment is an embodiment embodied in a forklift, and FIG. 1 is an electrical block circuit diagram of a control device that controls the rotation of an engine 4 mounted on a vehicle and controls the gear ratio of a continuously variable transmission 5. The engine 4 is used for cargo handling to drive driving wheels 6 via a continuously variable transmission 5, and to supply pressure oil to a cargo handling device, that is, a lift cylinder that moves the fork up and down, and a tail cylinder that tilts the mast in the front and rear directions. hydraulic pump 7
drive. Further, the opening degree of the throttle that adjusts the rotational speed of the engine 4 is controlled by a throttle actuator 8.

The continuously variable transmission 5 is composed of a variable displacement hydraulic pump 5a and a hydraulic motor 5b.The variable displacement hydraulic pump 5a is driven by the engine 4, and the hydraulic motor 5b is driven by the variable displacement hydraulic pump 5a. It rotates with hydraulic oil supplied by the drive and transmits its rotational force to the drive wheel 6. Variable displacement hydraulic pump 5a
In this embodiment, a swash plate type hydraulic pump is used, and the gear ratio is changed by changing the inclination angle of the swash plate. The angle of inclination of the swash plate that adjusts the gear ratio is appropriately controlled by a swash plate actuator 9.

On the other hand, the travel pedal 1 is provided with a depression angle detector 10 consisting of a potentiometer for detecting the depression angle thereof, and outputs a travel operation amount signal SG1 having a value proportional to the depression angle, that is, the amount of depression.

The lift lever 2 is used to drive the lift cylinder, and the lever 2 is provided with a lift lever operation amount detector 11 consisting of a potentiometer that detects the amount of operation of the lift cylinder, and the lift lever operation amount detector 11 is configured to detect a cargo handling operation proportional to the detected amount. Lift operation amount signal as quantity signal
Output SG2.

The tail lever 3 is used to drive the tail cylinder, and the lever 3 is provided with a tail lever operation amount detector 12 consisting of a potentiometer that detects the amount of operation. A tail operation amount signal SG3 is output as a cargo handling operation amount signal.

The driving function generator 13 to which the driving operation amount signal SG1 is input is a circuit that converts the input operation amount signal SG1 into engine rotation speed data A1 for driving, and converts the input operation amount signal SG1 into a function according to preset driving conditions. Based on the operation amount signal SG1 is the rotation speed data A1
is converted to In this embodiment, the function corresponding to the running conditions is set to a function in which the throttle opening of the engine 4 linearly increases as the operating amount increases, as shown in FIG. Therefore, according to this function, rotation speed data A1 for travel operation amount signal SG1 is output.

The lift function generator 14 to which the lift operation amount signal SG2 is input is a circuit that converts the input operation amount signal SG2 into engine rotation speed data A2 for driving the lift cylinder, and is a circuit that converts the input operation amount signal SG2 into data A2 of the engine rotation speed for driving the lift cylinder. Manipulated variable signal SG based on the function
2 is converted into rotation speed data A2. As shown in FIG. 1, the function corresponding to the cargo handling conditions was set to such a function that the throttle opening of the engine 4 increases linearly as the amount of operation increases when the fork is raised. Therefore, the rotation speed data A2 for the lift operation amount signal SG2 is output according to this function.

The tailing function generator 15 inputting the tailed manipulated variable signal SG3 receives the input manipulated variable signal SG.
This is a circuit for converting the signal SG3 into engine rotational speed data A3 for driving the tail cylinder, and converts the operation amount signal SG3 into rotational speed data A3 based on a function corresponding to preset cargo handling conditions. As shown in Figure 1, the function corresponding to the cargo handling conditions is set so that when the mast is tilted backwards or forwards, the throttle opening of the engine 4 increases linearly as the amount of operation increases. . Therefore,
According to this function, rotation speed data A3 for the tilt operation amount signal SG3 is output.

The optimum function for each of the function generators 13 to 15 is selected based on sensors (not shown) that detect the presence or absence of luggage and its weight, a sensor that detects vehicle speed, a sensor that detects the load during running, etc. It is also possible to determine the traveling conditions and cargo handling conditions and select the optimal number that meets the conditions.

Each of the rotational speed data A1 to A3 is output to the next stage selection circuit 16. The selection circuit 16 discriminates and selects the data having the largest value among the rotational speed data A1 to A3 (hereinafter referred to as maximum rotational speed data A), and outputs the selected data to the throttle actuator 8. Then, when the largest rotational speed data A selected by the selection circuit 16 is output to the throttle actuator 8, the actuator 8 adjusts the throttle based on the data A, and adjusts the throttle of the engine 4 based on the data A. Control the rotation speed.

The rotational speed data A1 outputted from the running function generator 13 and the maximum rotational speed data A selected and outputted by the selection circuit 16 are outputted to a comparator 17. The comparator 17 receives both data A and A1.
It is determined whether the values are the same and whether or not the engine 4 is being driven and controlled by the rotational speed data A1 based on the operation of the travel pedal 1. In other words, it is determined whether the cargo handling operation is being performed using the lift lever 2 or the tail lever 3. detecting whether or not
Then, the comparator 17 outputs a signal indicating the presence or absence of a cargo handling operation and, if a cargo handling operation is performed, a signal indicating the ratio of the amount of cargo handling operation ΔA=A−A1, or A/A1, or
A signal such as ΔA/A1 is output to the integrator 35 to adjust the gain.

Further, the traveling operation amount signal SG1 is output to the swash plate function generator 18. The swash plate function generator 18 is a circuit that converts the input operation amount signal SG1 into speed ratio data e for controlling the tilt angle (speed ratio) of the swash plate of the variable displacement hydraulic pump 5a, The manipulated variable signal SG1 is converted into gear ratio data e based on a function according to preset driving conditions.

In this embodiment, the function corresponding to the driving conditions has a dead band from zero to a small amount of operation, as shown in Figure 1, and in a larger area, it functions linearly as the amount of operation increases. It is set to a function that increases the throttle opening of engine 4. Therefore, the gear ratio data e for the traveling operation amount signal SG1 is output according to this function.

The vehicle speed calculator 19 is a circuit that calculates vehicle speed data v from the throttle signal A1 and the gear ratio data e, and calculates the vehicle speed v that should be obtained when the travel pedal 1 is operated in a state where no cargo handling operation is performed.
is output to the arithmetic unit 20.

The computing unit 20 calculates the vehicle speed data v and the continuously variable transmission 5.
The rotational speed of the hydraulic motor 5b, that is, the actual vehicle speed V
A detection signal from a vehicle speed detector 21 that detects the vehicle speed is inputted via a signal converter 22 as vehicle speed data V at that time. Then, the computing unit 20 calculates the difference △v (=V
-v) as the vehicle speed change amount data △v to the converter 23.
It is output to the next stage integrator 35 via.

The converter 23 corrects the swash plate angle of the variable displacement hydraulic pump 5a necessary to return the vehicle speed to the original speed by changing the gear ratio by the amount of change in vehicle speed V, that is, the change in vehicle speed V. It is converted into a corrected inclination angle amount Δe for the purpose of increasing the angle of inclination, and outputted to the integrator 35 at the next stage.
When the integrator 35 receives a signal from the comparator 17 indicating that a cargo handling operation is being carried out, the integrator 35 outputs a signal from the comparator 17.
The corrected inclination angle amount △e is integrated with the gain corresponding to the signal of the ratio of the cargo handling operation amount from 1 to the corrected inclination angle amount E.
It is converted to 1 and output to the next stage arithmetic unit 24. On the other hand, when a signal indicating that a cargo handling operation is not being performed is inputted, the integrator 35 does not perform the above calculation and outputs data of 0.

The arithmetic unit 24 corrects the gear ratio data e, which controls the tilt angle of the swash plate based on the travel pedal 1, which is output from the swash plate function generator 18, using the corrected tilt angle amount E1 to obtain a compensation gear ratio E(= e-E1) to the code converter 25.

The code converter 25 detects the operating position of the forward/reverse lever 26 and performs the compensation shift based on a detection signal SG4 from a detector 27 that detects whether the lever 26 is in forward, reverse, or neutral position. Ratio data E is output to the swash plate actuator 9. Then, in the case of forward movement, the compensation gear ratio data E is changed to a negative value in the case of reverse movement, and the compensation gear ratio data E is invalidated and set to 0 in the case of neutral movement, and the code converter 25 is output to the swash plate actuator 9.

The swash plate actuator 9 then adjusts the inclination angle of the swash plate based on the same data to control the gear ratio.

Next, the effects of the first embodiment configured as described above will be explained.

If you are currently driving by operating only the travel pedal 1, the travel operation amount signal SG is sent from the depression angle detector 10.
1 is output to the running function generator 13. The driving function generator 13 converts the driving operation amount signal SG1 into the rotation speed data A1 for driving according to the above-mentioned function, and outputs it to the selection circuit 16. Selection circuit 16
At this time, based on the fact that only the rotational speed data A1 is input, the same data A1 is outputted as the largest value data A to the throttle actuator 8, and the rotational speed of the engine 4 is controlled by the same actuator 8. do.

Further, the manipulated variable signal SG1 is output to the swash plate function generator 18. The swash plate function generator 18 converts the amount of depression of the travel pedal 1 into gear ratio data e according to the above-mentioned function and outputs it to the calculator 24. The data v is output to the arithmetic unit 20.

The calculator 20 calculates the difference between the vehicle speed data v calculated from the rotation speed data A1 and the gear ratio data e and the actual vehicle speed V at that time based on the detection signal from the vehicle speed detector 21, and calculates the vehicle speed change amount data Δv. (=V-
v) is calculated and output to the converter 23. converter 2
3 converts this into a corrected slope angle amount △e and integrator 3
Output to 5.

On the other hand, since the comparator 17 determines that the data A from the selection circuit 16 and the data A1 from the running function generator 13 are the same, the integrator 35
outputs a value of 0 to the next stage arithmetic unit 24 without performing any calculation. Therefore, the computing unit 24 outputs the gear ratio data e as it is to the swash plate actuator 9 via the sign converter 25 as compensation gear ratio data E (=e).

At this time, the gear ratio data E is output as is when the vehicle is traveling forward, and is converted to a negative value and output when the vehicle is traveling backwards. Then, the swash plate actuator 9 controls the gear ratio of the continuously variable transmission 5 by adjusting the inclination angle of the swash plate based on this gear ratio data E. Therefore, in this case, the gear ratio is controlled based on the depression of the travel pedal 1. Also, the forward/backward lever 26
When is neutral, actuator 9 is set to 0.
Since the compensating gear ratio data E is output, the inclination angle of the swash plate becomes 0.

Next, when the lift lever 2 is operated while driving, the rotation speed data A for driving is performed in the same way as above.
1 is output to the selection circuit 16. On the other hand, the lift lever operation amount detector 11 sends a lift operation amount signal SG.
2 is output to the lift function generator 14. The lift function generator 14 converts the lift operation amount signal SG2 into rotation speed data A2 for driving the lift cylinder according to the above-mentioned function and outputs it to the selection circuit 16.

The selection circuit 16 compares the magnitudes of both rotational speed data A1 and A2, selects the larger one, and selects the maximum rotational speed data A.
is output to the throttle actuator 8, which controls the rotational speed of the engine 4.

At this time, since the number of revolutions is required for cargo handling and the torque is required for traveling, the number of revolutions data A2 output from the lift function generator 14 is higher than the number of revolutions of the travel function generator 13. Since the data A is set to be a larger value than the data A1, the data A output from the selection circuit 16 becomes the rotation speed data A2. Therefore, in this case, the rotation speed N of the engine 4 is controlled based on the rotation speed data A2. That is, the rotational speed N of the engine 4 is no longer based on the amount of depression of the travel pedal 1, but increases based on the amount of operation of the lift lever 2. Along with this, the vehicle speed V increases if the gear ratio remains unchanged.

On the other hand, the calculator 20 calculates the difference between the vehicle speed data v based on the amount of depression of the travel pedal 1 and the actual vehicle speed V at that time based on the detection signal from the vehicle speed detector 21, and calculates the difference between the vehicle speed change data Δv (=V− v) is calculated and output to the converter 23.

The converter 23 converts this into a corrected inclination angle amount Δe and outputs it to the integrator 35. On the other hand, since the two data A1 and A2 input to the comparator 17 are different, the integrator 35 outputs a gain Δe corresponding to the signal of the ratio of the cargo handling operation amount output from the comparator 17.
is converted into a corrected inclination angle amount E1 and output to the arithmetic unit 24. The compensating gear ratio E (=e-
E1) is calculated and output to the swash plate actuator 9 via the code converter 25.

The swash plate actuator 9 adjusts the inclination angle of the swash plate based on this gear ratio data E, and controls the continuously variable transmission 5 to maintain the vehicle speed V at the vehicle speed before the cargo handling operation, that is, the vehicle speed v based on the amount of depression of the travel pedal 1. Convert the gear ratio. Therefore, when cargo handling operations are carried out while the vehicle is running, it is possible to compensate for fluctuations in vehicle speed based on cargo handling operations without requiring any sophisticated operating techniques.

Similarly, when the lift lever 2 or the tail lever 3 is operated in a stopped state, or when the tail lever 3 is operated while driving, the optimum rotation speed data A1 to A3 is output from each function generator 13 to 15. The rotation of the engine 4 is controlled under optimal conditions, and a corrected inclination angle amount △e is calculated based on the vehicle speed change amount data △v outputted from the calculator 20, and a corrected inclination angle amount E1 is calculated. , and the compensation gear ratio data E is obtained,
The gear ratio of the continuously variable transmission 5 is controlled and maintained at the vehicle speed before the cargo handling operation. Therefore, there is no need for advanced technology to keep the vehicle speed constant as in the past, and
It has the advantage of improving noise and fuel consumption.

In this embodiment, the functions of the rotation speed data A1 to A3 and the gear ratio data e to the manipulated variable signals SG1 to SG3 are determined by the function generators 13 to 15, 1, respectively.
Although the number is set to 8 in advance, the number may be further increased or decreased. Of course, it is also possible to set a function corresponding to a certain purpose different from the above and perform the processing based on that function.

Alternatively, the calculation may be performed using a functional formula including various conditions such as running load and cargo handling load.

Furthermore, when the rotation speed data A1 to A3 are input at the same time, the selection circuit 16 selects the largest rotation speed data among them, but it is also possible to select each rotation speed data and calculate the sum as the rotation speed data. You may.

Further, the depression angle detector 10, the lift lever operation amount detector 11, and the tail lever operation amount detector are not limited to potentiometers, but may be, for example, inductance type displacement meters or variable capacitance type displacement meters. It's okay.

Note that the gain adjustment may be performed by the converter 23 using a signal from the comparator 17 that is proportional to the cargo handling operation amount. Further, the comparator 17 outputs only a signal indicating whether or not a cargo handling operation has been performed, and the converter 23 and the integrator 3
The gain of 5 may be fixed. Thereby, the circuit for power adjustment of the comparator 17, the converter 23, and the integrator 35 can be omitted and the system can be simplified.

Furthermore, by appropriately selecting the gain of the converter 23, the integrator 35 can be omitted.

Furthermore, although the comparator 17 controls the calculation execution of the integrator 35, if the integrator 35 is omitted,
At the stage of outputting this from the arithmetic unit 20, △v may be cut off or output, or the converter 20 may
The corrected inclination angle amount Δe may be cut off or output at the stage where it is output from step 3. Also, comparator 17
is provided to calculate and control the gear ratio only when carrying out cargo handling operations while traveling, but can be omitted if Δv=0 when only traveling.
Instead of the comparator 17, the rotational speed data A1, A2 and the cargo handling operation amount signals SG2, SG3 may be detected, and the integrator 35 may be controlled using the detected signals.

Further, the continuously variable transmission 5 may be of any type as long as its gear ratio can be changed arbitrarily, such as a V-belt type continuously variable transmission.

In addition, the operating amounts of the travel pedal 1, lift lever 2, and tail lever 3 are converted into electrical signals to control the rotation speed of the engine 4, which is mechanically connected to the throttle of the engine 5 via this link, wire, etc. It may also be applied to cargo handling vehicles of this type. In this case, a pedal angle sensor and a throttle angle sensor are required.

Further, the code converter 25 does not need to be provided after the arithmetic unit 24, and may be provided, for example, before the swash plate function generator 18 or between the function generator 18 and the arithmetic unit 24. . In this case, computing unit 2
4, it is necessary to determine whether the gear ratio data e is positive or negative and perform calculations.

Furthermore, in this embodiment, the running pedal 1 can be replaced with a seesaw-type running pedal 1, which is operated as shown in FIG. 2, in which front depression is used to travel forward, and rear depression is operated to travel backward. In this case, when the rear depression is performed, the swash plate function generator 18 outputs negative gear ratio data e, and the absolute value is sent to the front stage of the vehicle speed calculator 19 to turn the negative data e into a positive value. It is necessary to provide a circuit 19a.

Further, the engine 4 may be replaced with a diesel engine, a gasoline engine, a motor, or the like, as long as it is a prime mover that performs both traveling and driving the cargo handling hydraulic pump.

Furthermore, although the throttle actuator 8 and the engine 4 are separated in this embodiment,
This may be integrated with the engine, such as an electronically controlled fuel injection device.

Furthermore, it may be applied to various cargo handling vehicles other than forklifts, such as shovel loaders and aerial work vehicles.

Second Embodiment The second embodiment is embodied in a forklift similar to the first embodiment, as shown in FIG.
The corrected inclination angle amount △e was calculated using only V-v), and the vehicle speed change data △v was divided by the engine 4 rotational speed N at that time, and the value (=△v/N) was calculated as the corrected inclination angle. The difference is that the amount is set to Δe.

Therefore, as shown in FIG. 3, a rotation detector 2 for detecting the rotation speed N of the engine 4 is used in place of the converter 23.
8. Requires the signal converter 29 and a divider 30 that divides the vehicle speed change data Δv by the rotational speed N.
This makes it possible to improve the convergence of feedback compared to the first embodiment.

In the case of a diesel engine with an all-speed governor, it is thought that the throttle signal and the engine speed N are proportional to each other, so the rotation detector 28 and signal converter 29 are omitted, and the maximum The rotation speed data A may also be used. or,
It is also possible to employ the seesaw type travel pedal used in the first embodiment.

Furthermore, the vehicle speed data v is calculated by the vehicle speed calculator 19 using the rotational speed data A1 and the gear ratio data e, and this is calculated by the operation amount signal as shown in FIG.
It may be implemented in place of the vehicle speed function generator 36 that converts SG1 into vehicle speed data v. That is, the vehicle speed function generator 36 is a circuit that outputs the vehicle speed v that should be obtained when the travel pedal 1 is operated.

Third Embodiment The third embodiment is an example in which a microcomputer is used.

As shown in Figure 5, each manipulated variable signal SG1~SG
3. Detection signal from the vehicle speed detector 21 and detection signal SG from the detector 27 provided on the forward/reverse lever 26
4 outputs to an electronic control unit 31 consisting of a central processing unit (CPU), a read-only memory (ROM) that stores control programs, and a readable and rewritable memory (RAM) that stores various data. be done. Based on these signals, arithmetic processing operations are executed according to the flowchart shown in FIG.

At this time, a predetermined function is selected based on a preset program to calculate the rotational speed data A1 to A3, gear ratio data e, and vehicle speed data v, and the calculations are performed according to the selected function. Further, the calculation of the maximum rotational speed data A, the vehicle speed change amount data Δv, the corrected inclination angle amount Δe, and the compensation gear ratio data E, and the control of the throttle actuator 8 and the inclination actuator 9 are also performed by the program. I am trying to make the process work.

As described in detail above, according to the present embodiment and its variations, the engine throttle is automatically controlled when cargo handling operations are performed while the vehicle is traveling, so troublesome engine operations during cargo handling operations are avoided. Not only is this unnecessary, but even if the vehicle speed changes due to cargo handling operations, if the drive pedal is held constant, the gear ratio is controlled to return the vehicle speed to its original state, making it possible to minimize the impact of cargo handling operations on vehicle speed. . Further, since traveling is performed by operating the travel pedal and cargo handling can be performed by the cargo handling operation device, extremely troublesome operations such as inching operations are freed. Furthermore, since the engine speed is increased only when necessary, it is possible to improve noise and fuel efficiency.

[Brief explanation of the drawing]

FIG. 1 is an electric block circuit diagram for explaining a first embodiment of the present invention, FIG. 2 is an electric block circuit diagram for explaining another example of the first embodiment, and FIG. 3 is an electric block circuit diagram for explaining another example of the first embodiment. An electric block circuit diagram for explaining the second embodiment, FIG. 4 is also an electric block circuit diagram,
FIG. 5 is an electric block circuit diagram for explaining the third embodiment of the present invention, and FIG. 6 is a flowchart showing the processing operation of the electronic control unit of the third embodiment. Travel pedal 1, lift lever 2, tilt lever 3, engine 4, continuously variable transmission 5, variable displacement hydraulic pump 5a, hydraulic motor 5b, throttle actuator 8, swash plate actuator 9, depression angle detector 10, Lift lever operation amount detector 11, tail lever operation amount detector 12, driving function generator 1
3. Lift function generator 14, tilt function generator 15, selection circuit 16, comparator 17, swash plate function generator 18, vehicle speed calculator 19, vehicle speed detector 2
1. Arithmetic units 20, 24, electronic control device 31.

Claims (1)

[Scope of Claims] 1. In a cargo-handling vehicle equipped with a cargo-handling device, in which a prime mover drives a cargo-handling hydraulic pump of the cargo-handling device, and the prime mover travels via a continuously variable transmission, when the vehicle is traveling. a calculation means for calculating the amount of change in vehicle speed based on the operation of the cargo handling operation device; and a calculation means for calculating the amount of change in vehicle speed based on the operation of the cargo handling operation device; A travel control device for a cargo handling vehicle, comprising means for calculating based on the calculated speed ratio, and control means for controlling the gear ratio of a continuously variable transmission based on the calculated gear ratio.