JPH10316391A - Tilt cylinder controlling device for industrial vehicle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent cargo from collapsing and wheel float of a forklift (longitudinally unstable state of a vehicle) from occurring even when a mast is operated to be tilted during running. SOLUTION: When a tilt lever is operated to be tilted forward, a driving controller 49 finds the maximum tolerant forward tilting angle of the mast 3 based on vehicle speed V detected by a vehicle speed detector S and a load W detected by a pressure sensor 17. The driving controller 49, when tilting angle of the mast 3 detected by a potentiometer 15 reaches the derived maximum tolerant forward tilting angle, controls a proportional solenoid valve 43 to stop hydraulic oil from being supplied to a tilt cylinder 9.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a tilt cylinder control device for an industrial vehicle in which a mast for raising and lowering a cargo handling attachment is tiltably provided, and the mast is tilted by operation of a tilt cylinder. The present invention relates to a control device that controls a tilt angle.

[0002]

2. Description of the Related Art In a forklift, which is an industrial vehicle of this kind, a fork is raised and lowered together with a lift bracket by a mast provided with an outer mast and an inner mast provided at a front portion of the vehicle. The mast expands and contracts by operating a lift lever to operate a lift cylinder. The fork moves up and down as the mast expands and contracts. In addition, in order to facilitate the cargo handling operation and to improve the stability during traveling of the forklift, the mast is tilted forward or backward with respect to the vertical reference position by operating the tilt lever to operate the tilt cylinder. It has become.

[0003] In a forklift, when a load is loaded on a fork, the center of gravity moves forward, and when the forklift height is increased, the moment acting on the mast increases. When the mast is tilted forward with a load being loaded, the center of gravity moves forward, and the stability of the forklift in the front-rear direction deteriorates. If the rearward tilt angle is excessively increased in a state where the load is large, the center of gravity is too close to the rear side, and the front wheels tend to float and slip may occur. Therefore, conventionally, the forward tilt angle and the backward tilt angle of the mast have been previously set to predetermined values (maximum allowable tilt angles). Generally, the forward lean angle is 6
Although the degree of inclination and the angle of rearward inclination are set to 12 degrees, a special forklift having a high mast may have an angle of forward inclination of 3 degrees and an angle of rearward inclination of 6 degrees.

[0004]

When the forklift is traveling, the mast has inertia corresponding to the traveling direction and traveling speed. During traveling, inertial force acts when the traveling speed changes or when the vehicle gets over a step or the like. This inertial force increases as the traveling speed of the vehicle increases.

Accordingly, in the conventional forklift, if the front tilt angle of the mast is tilted during traveling to the maximum tilted state which is the maximum allowable tilt angle of the fixed front side set in advance, the center of gravity of the vehicle moves to the front side. In addition to the movement, the inertial force corresponding to the traveling speed largely acts on the front side, so that there is a problem that the stability of the forklift in the front-rear direction is deteriorated. In addition, since the load loaded on the fork of the mast also has poor stability, if the tilt operation of the mast is made to be the most inclined during traveling, the load may fall. Conversely, when the rearward tilt angle of the mast during backward driving is tilted to the most tilted state, which is the preset maximum allowable tilt angle on the rear side, the position of the center of gravity of the vehicle moves to the rearmost side. At the same time, since the inertia force corresponding to the traveling speed largely acts on the rear side, there is a possibility that the front wheels tend to float and slip occurs.

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and its object is to reduce the load and lift the wheels of a forklift (that is, lift the wheels in the longitudinal direction of the vehicle) even when the mast is tilted during running. An object of the present invention is to provide a tilt cylinder control device for an industrial vehicle in which an unstable state does not occur.

[0007]

According to the first aspect of the present invention, there is provided an industrial vehicle in which a mast for raising and lowering a cargo handling attachment is tiltably provided, and the mast is tilted by operation of a tilt cylinder. The gist of the present invention is to provide a calculation drive control means for controlling the supply of hydraulic oil to the tilt cylinder so as to change the maximum allowable tilt angle in accordance with the traveling speed of the industrial vehicle.

[0008] The invention according to claim 2 is characterized in that the arithmetic drive control means changes the maximum allowable tilt angle in accordance with the center of gravity position in addition to the traveling speed of the industrial vehicle.

In the invention according to a third aspect of the present invention, the calculation drive control means changes the maximum allowable tilt angle in accordance with the load of the cargo handling attachment in addition to the traveling speed of the industrial vehicle. .

According to a fourth aspect of the present invention, the arithmetic drive control means changes the maximum allowable tilt angle in accordance with the elevation of the cargo handling attachment in addition to the traveling speed of the industrial vehicle. .

In the invention described in claim 5, the arithmetic drive control means corresponds to the maximum allowable tilt angle in addition to the traveling speed of the industrial vehicle and the lift of the cargo handling attachment and the load of the cargo handling attachment. The gist is to make changes.

According to the invention described in claim 6, in an industrial vehicle in which a mast for lifting and lowering the cargo handling attachment is tiltably provided and the mast is tilted by operation of a tilt cylinder, the traveling speed of the industrial vehicle is detected. Vehicle speed detecting means, center of gravity position detecting means for detecting the position of the center of gravity of the industrial vehicle, mast angle detecting means for detecting the tilt angle of the mast from a reference position, and guiding the maximum allowable tilt angle with respect to the traveling speed and the position of the center of gravity Storage means for storing data for; and calculating means for calculating a maximum permissible tilt angle of the mast at that time based on the traveling speed detected by the vehicle speed detecting means and the center of gravity position detected by the center of gravity position detecting means, When the tilt cylinder is actuated when tilting the mast, the tilt detected by the mast angle detecting means is detected. Angle is summarized as further comprising a drive control means for controlling the supply of hydraulic oil to the tilt cylinder to stop the tilting motion of the mast reaches the maximum allowed tilt angle of said calculating means is calculated.

According to a seventh aspect of the present invention, in the tilt cylinder control device for an industrial vehicle according to the sixth aspect, the center-of-gravity position detecting means is a load detecting means for detecting a load of the loading attachment. The main point is.

According to the invention described in claim 8, in the tilt cylinder control device for an industrial vehicle according to claim 6, the center of gravity position detecting means is a height detecting means for detecting a height of the cargo handling attachment. The main point is.

According to a ninth aspect of the present invention, in the tilt cylinder control device for an industrial vehicle according to the sixth aspect, the center-of-gravity position detecting means detects the loading load of the loading attachment, and the load handling means. It is intended to comprise a lift detecting means for detecting the lift of the attachment.

According to a tenth aspect of the present invention, the drive control means for controlling the supply of the hydraulic oil to the tilt cylinder includes a manual operation direction switching valve for controlling the supply and the discharge of the hydraulic oil to the tilt cylinder. An electromagnetic valve provided in the middle of a pipe connecting the manual operation direction switching valve and the tilt cylinder, and when the tilt cylinder is operated when tilting the mast, the mast angle becomes a predetermined angle. And a drive control device for controlling the solenoid valve to a state in which the pipeline is shut off.

Therefore, according to the first aspect of the present invention,
When the mast is tilted, the maximum allowable tilt angle of the mast is changed by the arithmetic drive control means in accordance with the traveling speed of the industrial vehicle. Therefore, even if the tilting operation is performed during traveling, there is no possibility that the load collapses and the wheels are lifted unlike the conventional device.

According to the second aspect of the present invention, when the mast is tilted, the maximum allowable tilt angle of the mast is changed by the arithmetic drive control means in accordance with the traveling speed and the position of the center of gravity of the industrial vehicle. Therefore, even if the tilting operation is performed during traveling, the position of the center of gravity at that time is taken into consideration, and there is no risk of collapse of the load or lifting of the wheels unlike the conventional device.

According to the third aspect of the present invention, at the time of the tilting operation of the mast, the maximum allowable tilting angle of the mast is changed by the arithmetic drive control means in accordance with the traveling speed of the industrial vehicle and the load of the loading attachment. Is done. Therefore, even if the tilting operation is performed during traveling under a high load, there is no possibility that the collapse of the load or the lifting of the wheels occurs as in the conventional device.

According to the fourth aspect of the present invention, when the mast is tilted, the maximum allowable tilt angle of the mast is changed by the arithmetic drive control means in accordance with the traveling speed of the industrial vehicle and the lift of the cargo handling attachment. Is done. Therefore, even if the tilting operation is performed during traveling at a high elevation, there is no risk of collapse of the load or lifting of the wheels unlike the conventional device.

According to the fifth aspect of the present invention, when the mast is tilted, the maximum permissible tilt angle of the mast is calculated and controlled according to the traveling speed of the industrial vehicle, the load of the loading attachment and the lift. Will be changed by Therefore, even if the tilting operation is performed during traveling under a high load and a high lift, there is no possibility that the load collapses and the wheels are lifted unlike the conventional apparatus.

According to the invention described in claim 6, the traveling speed of the industrial vehicle is detected by the vehicle speed detecting means. The center of gravity position of the industrial vehicle at that time is detected by the center of gravity position detecting means. The tilt angle of the mast from the reference position is detected by the mast angle detecting means. The maximum permissible tilt angle of the mast is calculated by the calculating means on the basis of the position of the center of gravity at that time detected by the center of gravity position detecting means and the traveling speed detected by the vehicle speed detecting means. During the operation of the tilt cylinder when tilting the mast, when the tilt angle of the mast detected by the mast angle detection means reaches the maximum allowable tilt angle, the supply of hydraulic oil to the tilt cylinder is stopped by the drive control means. Then, the tilting operation of the mast is stopped. That is, during the tilting operation of the mast, the mast is reliably prevented from tilting until it becomes larger than an appropriate angle corresponding to the traveling speed and the position of the center of gravity.

According to the seventh aspect of the present invention, the load of the cargo attachment is detected by the load detecting means. Then, the maximum permissible tilt angle of the mast is calculated by the calculating means based on the loaded load detected by the loaded load detecting means and the traveling speed detected by the vehicle speed detecting means. Therefore, at the time of the mast tilting operation, the mast tilting angle is reliably prevented from becoming larger than the maximum allowable tilting angle obtained in accordance with the traveling speed and the loaded load.

According to the invention described in claim 8, the lift of the cargo handling attachment is detected by the lift detecting means.
Then, the maximum allowable tilt angle of the mast is calculated by the calculating means based on the lift detected by the height detecting means and the traveling speed detected by the vehicle speed detecting means. Therefore, at the time of the mast tilting operation, the tilt angle of the mast is reliably prevented from being larger than the maximum allowable tilt angle obtained according to the traveling speed and the lift.

According to the ninth aspect of the present invention, based on the load detected by the load detecting means, the lift detected by the lift detecting means, and the traveling speed detected by the vehicle speed detecting means. The maximum permissible tilt angle of the mast is calculated by the calculating means. Therefore, when the mast is tilted, the tilt angle of the mast is reliably prevented from being larger than the maximum allowable tilt angle obtained in accordance with the load, the lift, and the traveling speed.

According to a tenth aspect of the present invention, in the invention according to any one of the sixth to ninth aspects, the supply and discharge of the hydraulic oil to and from the tilt cylinder are performed by a manually operated direction switching valve. And a solenoid valve. The solenoid valve controls the flow of hydraulic oil in a pipe connecting the manually operated directional control valve and the tilt cylinder. When the manual operation direction switching valve is switched to the operation position for tilting the mast and the tilt cylinder is operated to tilt the mast, and the mast angle reaches the maximum allowable tilt angle, the solenoid valve is turned by the drive control device. It is controlled to the line cutoff state. Therefore, even if the manual operation direction switching valve is held at the operation position for tilting the mast, the operation of the tilt cylinder is stopped,
The mast is held at the maximum allowable tilt angle.

[0027]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment in which the present invention is embodied in a forklift as an industrial vehicle to which a fork is attached as a cargo handling attachment will be described with reference to FIGS.

As shown in FIG. 3, a mast 3 is provided at the front of the body frame 2 of the forklift 1. The mast 3 includes a pair of left and right outer masts 3a that are supported to be tiltable with respect to the body frame 2, and inner masts 3b that are provided inside the masts 3 so as to be able to move up and down. A lift cylinder 4 is fixed to the rear side of both outer masts 3a in parallel with the outer mast 3a, and the tip of a piston rod 4a is connected to the upper part of the inner mast 3b. A lift bracket 5 is provided inside the inner mast 3b so as to be able to move up and down along the inner mast 3b, and a fork 6 is attached to the lift bracket 5. Innamasto 3
A chain wheel 7 is supported on an upper part of the lift cylinder 4, and a first end of the chain wheel 7 is provided on an upper part of the lift cylinder 4.
A chain 8 having a second end connected to the lift bracket 5 is mounted. And lift cylinder 4
The fork 6 is moved up and down together with the lift bracket 5 via the chain 8 by the expansion and contraction of the fork 6.

A base end of a tilt cylinder 9 is rotatably supported on both left and right sides of the body frame 2, and a distal end of a piston rod 9a is rotatably connected to the outer mast 3a. Then, the mast 3 is tilted by the expansion and contraction of the piston rod 9a of the tilt cylinder 9.

The front of the cab 10 has a steering wheel 11,
A lift lever 12 and a tilt lever 13 are provided, respectively. FIG. 3 shows both levers 12 and 13 in an overlapping state. The operation of the lift lever 12 causes the lift cylinder 4 to expand and contract, and the tilt lever 13
The tilt cylinder 9 is extended and contracted by the tilting operation of.

As shown in FIG. 2, the outer mast 3a is provided with a height sensor 14 as a center of gravity position detecting means and a height detecting means at predetermined height positions. Lift sensor 1
Reference numeral 4 denotes a proximity switch, which detects a target portion (not shown) fixed to the inner mast 3b to detect whether the height is high or low. That is, an on signal is output when the lift of the fork 6 is equal to or higher than the set value H0, and an off signal is output when the lift is less than the set value H0. In this embodiment, the set value H0 is set to approximately half the maximum lift Hmax.

The body frame 2 is provided with a rotary potentiometer 15 as mast angle detecting means. The potentiometer 15 is provided on a support portion rotatably supporting the base end of the tilt cylinder 9, and includes a rotary piece 15 a for holding a pin 9 d protruding from the tilt cylinder 9. The rotation piece 15a rotates together with the tilt cylinder 9 in accordance with the expansion and contraction of the piston rod 9a, and a detection signal corresponding to a tilt angle (tilt angle) θ from a reference position at which the mast 3 is vertical is transmitted to the potentiometer 1.
5 is output.

The lift cylinder 4 is provided with a center-of-gravity position detecting means for detecting a loaded load (load) w of the fork 6 and a pressure sensor 17 as a loaded load detecting means. The pressure sensor 17 detects the oil pressure inside the lift cylinder 4 and outputs a detection signal corresponding to the load w of the fork 6.

A not-shown differential ring gear of the front wheel 16 is provided with a vehicle speed sensor S as vehicle speed detecting means.
The vehicle speed sensor S detects the rotation of the differential ring gear and outputs a detection signal corresponding to the traveling speed (vehicle speed) V of the forklift 1.

As shown in FIG. 4, near the tilt lever 13, a forward tilt detecting switch 18 and a rear tilt detecting switch 1 are provided.
9 are provided. Both of the detection switches 18 and 19 are micro switches, the forward tilt detection switch 18 outputs an ON signal when the tilt lever 13 is in the forward tilt position, and the rear tilt detection switch 19 is in the tilt lever 13 when the tilt lever 13 is in the rear tilt position. Sometimes outputs an ON signal.

Next, a hydraulic circuit for driving the lift cylinder 4 and the tilt cylinder 9 will be described with reference to FIG. As shown in FIG. 1, the lift cylinder 4 is connected to a lift control valve 22 via a pipe 20. Pipe line 20
The pilot operated check valve 21 for restricting the flow of hydraulic oil from the bottom chamber 4b side to the lift control valve 22
Is provided. As the lift control valve 22, a direct-acting spool valve is used. The lift control valve 22 is a manually operated 7 port 3 position switching valve.
Can be switched to three states of a position, b position, and c position in accordance with the lifting, neutral, and lowering operation positions of the lift lever 12 for instructing the lifting, lowering, and stopping of the lift lever 12. The manually operated directional control valve 23 has a manually operated 6
A port 3 position switching valve is used to switch the tilt lever 13 between three positions, a position, b position, and c position, corresponding to the forward tilt, neutral, and rear tilt operating positions of the tilt lever 13 for instructing the fork 6 to tilt and stop. It is possible.

The hydraulic pump 25 for supplying the hydraulic oil in the oil tank 24 to each of the cylinders 4 and 9 is driven by the engine E. The hydraulic pump 25 is connected to a port P1 of the lift control valve 22 via a hydraulic oil supply line 26. The hydraulic oil supplied from the hydraulic pump 25 is supplied to the hydraulic oil supply pipe 26 via the cargo handling device side (the lift cylinder 4 and the tilt cylinder 9) and the power steering valve 27.
A flow divider 28 is provided for branching to the side.
The hydraulic oil supply pipe 26 is connected to ports P2 and P3 via branch pipes 26a and 26b branched downstream of the flow divider 28, respectively. A check valve 29 is provided in the branch conduit 26a. The hydraulic oil supply line 26 is connected to a return line 32 via a line 31 a provided with a relief valve 30. The lift control valve 22 is connected to the return line 32 at the port T1, to the line 20 at the port A1, to the line 31b at the port A2, and to the line 34 at the port A3. The pipe 31b is connected to the return pipe 32, and a relief valve 33 is provided on the way. The set pressure of the relief valve 33 is set to a value smaller than the set pressure of the relief valve 30.

The lift control valve 22 is disposed at the position a based on the lifting operation of the lift lever 12, and connects the branch line 26a and the line 20 at the position a to extend the lift cylinder 4. The lift control valve 22 is disposed at the position c based on the lowering operation of the lift lever 12, and branches the line 20 and the return line 32, the hydraulic oil supply line 26 and the line 34 at the position c. The pipe 26b and the pipe 31b are communicated with each other to contract the lift cylinder 4.

The lift control valve 22 is disposed at the position b based on the neutral operation of the lift lever 12, and connects the hydraulic oil supply line 26 and the line 34 to the branch line 26b at the position b. 31b. And
The communication between the pipe 20 and the branch pipe 26a and the return pipe 32 is interrupted, and the state in which the movement of the hydraulic oil in the lift cylinder 4 is prevented is maintained.

The hydraulic pump 25 is connected to a port P11 of the tilt control valve 23 via a hydraulic oil supply pipe 35 branched from the hydraulic oil supply pipe 26. A check valve 36 is provided in the hydraulic oil supply pipe 35. A pipe 34 is connected to a port P12 of the tilt control valve 23. The tilt control valve 23 is connected to the return line 32a at the port T11 and to the return line 32b at the port T12. Port A for tilt control valve 23
11 at line 37a and port A12 at line 37.
b. The pipe 37a is in the rod chamber 9b of the tilt cylinder 9, and the pipe 37b is in the bottom chamber 9c.
Connected to each other.

The tilt control valve 23 is disposed at the position a based on the backward tilting operation of the tilt lever 13, and at the position a, the hydraulic oil supply pipe 35 and the pipe 37a are connected, and the return pipe 32a and the pipe are connected. 37b and the tilt cylinder 9 can be contracted. The tilt control valve 23 is arranged at the position c based on the forward tilt operation of the tilt lever 13. At the position c, the hydraulic oil supply pipe 35 and the pipe 37b are communicated with each other, and the pipe 37a is placed in communication with the return pipe 32a so that the tilt cylinder 9 can be extended. The tilt control valve 23 is disposed at the position b in FIG. 1 based on the neutral operation of the tilt lever 13, and cuts off the communication between the two pipes 37a, 37b, the hydraulic oil supply pipe 35, and the return pipe 32a. Then, the state in which the movement of the hydraulic oil in the tilt cylinder 9 is prevented is maintained.

A control valve 38 and a pilot operation check valve 39 are provided in the middle of the conduit 37a. The pilot operation check valve 39 regulates the flow of hydraulic oil from the rod chamber 9b to the control valve 38 between the control valve 38 and the rod chamber 9b. The control valve 38 is a one-way valve, and includes a direct-acting spool that opens and closes the conduit 37a. The control valve 38 is a normally-closed control valve, and a 2-port 2-position valve operated by pilot hydraulic pressure is used. The control valve 38 closes the conduit 37 a by the spring force of the spring 40 and the conduit 37 a. It is possible to switch between two positions, that is, the communicating position b. When the spool is located at the position b, the line 37a
Is formed, and an orifice 42 is provided in the passage 41. The pilot pressure to the control valve 38 and the pilot operated check valve 39 is proportional solenoid valve 43
Supplied by Control valve 38 and proportional solenoid valve 4
3, the tilt cylinder 9 and the tilt control valve 23
And a solenoid valve for opening and closing a conduit 37a connecting the two.

The pilot pressure supply means for supplying the pilot pressure to the pilot operation check valves 21 and 39 and the proportional solenoid valve 43 is provided at a position upstream of the flow divider 28 of the hydraulic oil supply line 26. It is constituted by a pipeline 44 branched from 26. A pressure reducing valve 45 and a filter 46 are provided in the middle of the pipe 44.

The proportional solenoid valve 43 has a tank port T2 connected to the return line 32a, and an A port connected to the line 4
4 is connected. In addition, B of the proportional solenoid valve 43
The port communicates with a pressure chamber (not shown) provided at one end of the spool of the control valve 38. In the control valve 38, a pressure chamber (not shown) at the other end of the spool is connected to the return line 32.

The proportional solenoid valve 43 is a normally closed type solenoid valve. When the solenoid is demagnetized, the B port and the tank port T
2 is communicated. The proportional solenoid valve 43 is configured such that the operation amount of the spool is substantially proportional to the current supplied for excitation. Proportional solenoid valve 43
When the solenoid is energized, the spool operates and the ports A and B communicate with each other, and supplies the pilot pressure set at the operating position of the spool to the spool of the control valve 38. By this pilot pressure, the spool of the control valve 38 is moved against the spring force of the spring 40.

The lift control valve 22, the tilt control valve 23, the pilot operated check valves 21, 39, the check valve 2
9, 36, the relief valves 30, 33, the control valve 38, the proportional solenoid valve 43, and the pressure reducing valve 45 are formed in one housing, and one control valve 48 as a whole.
Is composed.

Next, an electrical configuration for controlling the hydraulic circuit will be described. As shown in FIG. 2, a drive control device 49 for controlling the opening of the control valve 38, that is, the output pilot pressure of the proportional solenoid valve 43, includes a microcomputer 50, an analog / digital conversion circuit (A / D conversion circuit) 51, and a solenoid. A drive circuit 52 is provided. The microcomputer 50 includes a central processing unit (hereinafter referred to as a CP) as an arithmetic unit.
U) 53 and a read-only memory (ROM) 54a
And an EEPROM (Electrical Era) as a storage means.
A sable programmable ROM (ROM) 54b, a readable and rewritable memory (RAM) 55, an input interface 56, and an output interface 57 are provided. In this embodiment, the tilt control valve 23, the control valve 3
8. The drive control means for controlling the supply of the hydraulic oil to the tilt cylinder 9 is constituted by the proportional solenoid valve 43 and the drive control device 49. The control means and C
The PU 53 constitutes an arithmetic drive control unit.

The ROM 54a stores (stores) various control programs including the program for the forward tilt angle regulation control process shown in the flowchart of FIG. 5, and data necessary for executing the programs.

The EEPROM 54b stores, as data necessary for executing the program of the forward lean angle restriction control processing,
A set value V1 for determining whether the vehicle speed V of the forklift is high or not, and a load w and a maximum allowable forward tilt angle θx as a maximum allowable tilt angle during high-speed running at or above the set value V1 shown in FIG. And a map representing the relationship with. In the present embodiment, the maximum allowable forward tilt angle θx
Is a value between the maximum forward tilt angle θmax and the minimum forward tilt angle θmin according to the load w, and the values are 6 ° (θmax), 5
Five kinds of values of °, 4 °, 3 °, and 2 ° (θmin) are set.

The CPU 53 is connected to the potentiometer 15, the pressure sensor 17, and the vehicle speed sensor S via the A / D conversion circuit 51 and the input interface 56, respectively. The CPU 53 is connected to the elevation sensor 14, the forward tilt detection switch 18, and the rear tilt detection switch 19 via the input interface 56. The CPU 53 is connected to the solenoid drive circuit 52 via the output interface 57.

The CPU 53 is provided for each of the sensors 14, 15, 1
7, S and the output signals of both switches 18 and 19 are input, and operate according to various control programs stored in the ROM 54a. When the tilt cylinder 9 is operated, the proportional solenoid valve is output via the output interface 57 and the solenoid drive circuit 52. And outputs a control command signal to the controller 43.

Next, the operation of the device configured as described above will be described. When the engine E is operated and the hydraulic pump 25 is driven, the operating oil in the oil tank 24 is discharged to the operating oil supply pipe 26. Therefore, the pipeline 44 for supplying the pilot pressure is in a state where the pilot pressure can be supplied as soon as the hydraulic pump 25 is driven, and the pilot operation check valve 21 provided on the pipeline 20 is moved from the bottom chamber 4b side. The state where the flow of the hydraulic oil to the lift control valve 22 side is also allowed is maintained.

When the lift lever 12 is raised from the neutral position, the spool of the lift control valve 22 is disposed at the position a, and the hydraulic oil supply pipe 26 is in communication with the pipe 20. Then, the hydraulic oil discharged from the hydraulic pump 25 is supplied to the bottom chamber 4b of the lift cylinder 4 through the hydraulic oil supply pipe 26, the lift control valve 22, and the pipe 20, and the lift cylinder 4 is extended. The fork 6 rises.

When the lift lever 12 is lowered, the spool of the lift control valve 22 is located at the position c, and the line 2
0 is communicated with the return pipe 32, and the hydraulic oil in the bottom chamber 4b is returned to the oil tank 24. Then, the lift cylinder 4 contracts and the fork 6 descends. Lift lever 1
Based on the second neutral operation, the lift spool is arranged at the position “b”, and the communication of the pipeline 20 to both the hydraulic oil supply pipeline 26 and the return pipeline 32 is cut off. as a result,
The movement of the hydraulic oil in the lift cylinder 4 is prevented, and the fork 6 is held at a desired position.

When the tilt lever 13 is in the neutral position, the spool is held at the position b in FIG.
a and 37b are a hydraulic oil supply line 35 and a return line 32a.
Are kept in a state where the communication is interrupted. Then, movement of the hydraulic oil of the tilt cylinder 9 is prevented, and the mast 3 is maintained at a desired tilt angle.

When the spool is disposed at the position c by the tilting operation of the tilt lever 13, the hydraulic oil supply pipe 35 and the pipe 37b are connected, and the pipe 37a and the return pipe 32a are connected.
Is in a state of being communicated with. On the other hand, the tilt lever 13
Is operated forward, the CPU 53 causes the forward lean detection switch 1
8 is input. When an ON signal is input from the forward tilt detection switch 18, the CPU 53 performs a forward tilt angle restriction control process described later. In the above processing, the vehicle speed V and the load w
An excitation command signal is output to the solenoid drive circuit 52 according to the tilt angle (tilt angle) θ. When the excitation command signal is input to the solenoid drive circuit 52, a valve-opening current is output from the solenoid drive circuit 52 to the proportional solenoid valve 43, and the proportional solenoid valve 43 opens according to the valve-opening current. . Then, pilot pressure is supplied to the control valve 38 and the pilot operation check valve 39 in the pipeline 37a,
The state in which the hydraulic oil can flow through the pipeline 37a is established.
Then, the hydraulic oil is supplied to the bottom chamber 9c through the hydraulic oil supply pipe 35 and the pipe 37b, and the hydraulic oil in the rod chamber 9b is discharged to the oil tank 24 through the pipe 37a and the return pipe 32a. Therefore, the tilt cylinder 9 is extended, and the mast 3 is rotated toward the front side. Mast 3
Is turned (tilted) forward from the vertical state (0 °), the mast 3, that is, the fork 6 is tilted forward.

When the spool is disposed at the position a by the tilting operation of the tilt lever 13, the hydraulic oil supply pipe 35 and the pipe 37a are connected, and the pipe 37b and the return pipe 32a are connected. It will be in the state to be done. On the other hand, when the tilt lever 13 is tilted backward, an ON signal of the rearward tilt detection switch 19 is input to the CPU 53. Back tilt detection switch 1
When an ON signal is input from 9, the CPU 53 outputs an excitation command signal to the solenoid drive circuit 52. When the excitation command signal is input to the solenoid drive circuit 52, a valve-opening current is output from the solenoid drive circuit 52 to the proportional solenoid valve 43, and the proportional solenoid valve 43 opens according to the valve-opening current. . Then, the control valve 3 in the pipe 37a
The pilot pressure is supplied to the pilot operation check valve 8 and the pilot operation check valve 39, and the hydraulic oil is allowed to flow through the pipeline 37a. Then, the operating oil is supplied to the rod chamber 9b through the operating oil supply pipe 35 and the pipe 37a, and the bottom chamber 9c
The hydraulic oil in the cylinder is discharged to the oil tank 24 via the pipe 37b and the return pipe 32a.
Is contracted, and the mast 3 is rotated rearward. When the mast 3 is rotated (tilted) rearward from the vertical state, the mast 3, that is, the fork 6 is tilted rearward.

Further, the CPU 53 has the two detection switches 18,
If no ON signal is output from any of the signals 19, no excitation command signal is output to the solenoid drive circuit 52. Therefore, the proportional solenoid valve 4
Since no current is output to the control valve 3 and no pilot pressure is supplied to the control valve 38 and the pilot operation check valve 39, the flow of the hydraulic oil from the rod chamber 9b to the tilt control valve 23 is maintained. Is done.

Next, the forward lean angle restriction control process will be described with reference to the flowchart shown in FIG. First, when the tilt lever 13 is tilted forward and the forward tilt detection switch 18 is turned on, the CPU 53 reads the values of the vehicle speed V, the load w, and the tilt angle (tilt angle) θ in step 1 and proceeds to step 2. In step 2, the set value V1 stored in the EEPROM 54b is read, and the set value V1 is compared with the vehicle speed V. When the CPU 53 determines in step 2 that the detected vehicle speed V is lower than the set value V1, the CPU 53 proceeds to step 3 and outputs an excitation command signal to the solenoid drive circuit 52. On the other hand, if it is determined in step 2 that the detected vehicle speed V is equal to or higher than the set value V1, the process proceeds to step 4. In step 4, the maximum allowable forward tilt angle θx is obtained from the load w using the map shown in FIG. 6 stored in the EEPROM 54b. The maximum allowable forward inclination angle θx is 6 ° (θmax) when the load w is less than w1, 5 ° when the load w is w1 or more and less than w2, 4 ° when the load w is w2 or more and less than w3, and the load w Is 3 ° when w3 or more and less than w4, and 2 ° (θmin) when the load w is w4 or more. Note that w1 to w4
Have a relationship of w1 <w2 <w3 <w4.

In the next step 5, the detected tilt angle θ
And the maximum allowable forward tilt angle θx obtained in step 4 is compared. The CPU 53 determines in step 5 that the tilt angle θ
Is smaller than the maximum allowable forward inclination angle θx,
Then, an excitation command signal is output to the solenoid drive circuit 52. If it is determined in step 5 that the tilt angle θ is equal to or larger than the maximum allowable forward tilt angle θx, the process proceeds to step 6 so that the excitation command signal is not output to the solenoid drive circuit 52. Accordingly, the pilot pressure is not applied to the control valve 38, and the control valve 38 is closed. As a result, the tilt cylinder 9 stops. Then, when the step 3 or the step 6 is completed, the process shifts to the step 1 to repeat the forward tilt angle regulation control process. Note that the forward tilt angle restriction control process is performed when the CPU 53 does not receive the ON signal of the forward tilt detection switch 18, that is, the tilt lever 1.
The process ends when the forward leaning operation of No. 3 ends.

That is, in this process, when the vehicle speed V is equal to or more than the set value V1 and the load w is equal to or more than w1, the maximum allowable forward tilt angle θx is obtained in accordance with the load w. When the inclination angle is equal to or larger than θx, the mast 3 is prevented from further tilting.

According to the embodiment described in detail above, the following effects can be obtained. (1) In the above embodiment, the maximum permissible forward inclination angle of the mast 3 is set in accordance with the traveling speed (vehicle speed) V of the forklift 1 and the load w of the fork 6 (loading attachment) for changing the position of the center of gravity of the forklift 1. Change and mast 3
Reaches the maximum allowable forward tilt angle, the tilt cylinder 9
Control means for controlling the supply of hydraulic oil to the vehicle, so that the mast 3 has an appropriate forward inclination angle θ corresponding to the vehicle speed V and the load w.
Further leaning beyond x is prevented. Therefore,
Even if the tilt lever 13 is tilted to the most forward tilt position due to erroneous operation during forward leaning operation with a high load during traveling, the mast 3 does not lean forward, that is, the center of gravity does not further move forward, so the front and rear of the vehicle There is no deterioration in directional stability. As a result, the lift of the rear wheel of the forklift 1 is prevented, and the collapse of the load does not occur.

(2) The control means for controlling the supply of the hydraulic oil to the tilt cylinder 9 comprises a tilt control valve 23 for controlling the supply and discharge of the hydraulic oil to the tilt cylinder 9.
(Manual operation direction switching valve), and a control valve 38 controlled by a command signal from a control device 49 provided in the middle of a pipe 37a connecting the tilt control valve 23 and the tilt cylinder 9. . Accordingly, the operator can perform the tilting operation by the same operation as the conventional manually operated valve, and when the tilting angle θ reaches the maximum allowable tilting angle θx as the maximum allowable tilting angle during the forward tilting operation of the mast 3, the control is performed. The control valve 38 is controlled so as to shut off the pipe 37a by a command from the device 49, and the forward inclination of the mast 3 is regulated.

(3) In the above embodiment, since the map showing the relationship between the set value V1 and the load w and the maximum allowable forward tilt angle θx is stored in the EEPROM 54b, even if a different map is required depending on the model, EEPROM 54
By modifying or adding a part of the stored contents of b,
It can be easily handled by the same control device.

The embodiments are not limited to the above-described embodiments, but may be modified as follows, for example. In the above-described embodiment, the mast 3 can be tilted by outputting the excitation command signal to the solenoid drive circuit 52 irrespective of the load w when the vehicle speed V is running at a low speed of less than V1, but the vehicle speed V is less than V1. Also at this time, the maximum allowable forward tilt angle θx is obtained according to the load w, and when the tilt angle θ at that time is equal to or greater than the maximum allowable forward tilt angle θx, the mast 3 may not be tilted. In this case, the load w and the maximum allowable forward tilt angle θx at the time of low-speed traveling stored in the EEPROM 54b are stored.
Is different from the map at the time of high-speed running shown in FIG. 6, for example, when the load w is less than w3.
The map is set to be 5 ° when the load w is equal to or more than w3 and less than w4, and set to 4 ° when the load w is equal to or more than w4.
In this manner, the maximum allowable forward tilt angle θx can be set more finely in accordance with the vehicle speed V and the load w, and the lifting of the rear wheel of the forklift 1 and the collapse of the load can be more reliably prevented. Alternatively, the vehicle speed V may be determined in a plurality of stages of three or more stages or continuously, and the maximum allowable forward inclination angle θx may be decreased in a plurality of stages or continuously as the vehicle speed V increases.

In the above embodiment, the vehicle speed V and the load w
The maximum allowable forward tilt angle θx is determined according to the following equation. However, the maximum allowable forward tilt angle θx may be determined according to the vehicle speed V and the lift H of the fork 6. More specifically, the lift H is detected using the lift sensor 14 of the above-described embodiment or a reel-type lift sensor capable of continuously detecting the lift H, and the set value V1 is detected. During the above-described high-speed running, the maximum allowable forward tilt angle θx is set to decrease as the lift H increases. In this case, the EEPROM 54b needs to store a map representing the relationship between the lift H and the maximum allowable forward tilt angle θx. This prevents the mast 3 from leaning forward beyond a proper forward tilt angle corresponding to the vehicle speed V and the lift H.

The maximum allowable forward tilt angle θx may be determined according to the vehicle speed V, the load w, and the lift H of the fork 6. This forward tilt angle restriction control process is, for example, performed as follows in detail. First, for example, using a three-dimensional map as shown in FIG. 7, a proportional coefficient K at that time is obtained from the detected load w and the lift H. Note that this proportional coefficient K
Is smaller as the load w is larger, and smaller as the lift H is higher, as shown in FIG.
It is set to be a value of ~ 6. Next, for example, the vehicle speed V is determined in three stages, and the coefficient L at that time is obtained. More specifically, for example, when the vehicle speed V is lower than Va, the coefficient L is 1.
0, when the vehicle speed V is equal to or higher than Va and lower than Vb, the coefficient L is equal to 0.
8. The coefficient L is set to be 0.6 when the vehicle speed V is equal to or higher than Vb. In addition, Va-Vc is Va>Vb> Vc.
In a relationship. Then, the maximum allowable forward tilt angle θx (= L * K) is obtained by multiplying the coefficient L thus obtained by the proportional coefficient K obtained from the load w and the lift H. Then, the calculated maximum allowable forward tilt angle θx is compared with the detected tilt angle θ. When it is determined that the tilt angle θ is smaller than the maximum allowable forward tilt angle θx, an excitation command signal is output to the solenoid drive circuit 52. If it is determined that the tilt angle θ is equal to or larger than the maximum allowable forward tilt angle θx, the excitation command signal is not output to the solenoid drive circuit 52.

For example, when the vehicle speed V is small and the coefficient L is 1.0
When the proportional coefficient K is 6 at a low load and a low lift, the mast 3 can tilt up to a maximum range of 6 °. Also, when the vehicle speed V is large, the coefficient L is 0.6, and the proportional coefficient K is 2 at high load and high lift, the mast 3 can be tilted in the minimum range of 1.2 °. In this case, of course, EEPR
The OM 54b stores Va to Vc, a coefficient K for each vehicle speed, a map shown in FIG. 7, and the like.

In this manner, the mast 3 is prevented from leaning forward beyond a proper forward tilt angle corresponding to the vehicle speed V, the load w and the lift H. In addition, since the detected values V, w, and H are determined in a plurality of steps to determine the maximum allowable forward tilt angle θx, the tilting operation is more finely controlled in accordance with the vehicle speed V, the load w, and the height H, and the tilt operation is performed during Workability is improved. Note that the detection values V, w, and H may be continuously determined, and the maximum allowable forward tilt angle θx may be continuously determined.

In the configuration of the above embodiment, the pipe 3
A solenoid valve (on / off solenoid valve) that only opens and closes the conduit 37a is provided in the control valve 7a in place of the control valve 38 whose opening can be adjusted by the pilot pressure. Specifically, the control valve 3
8. Pilot operated check valve 39 and proportional solenoid valve 4
3 is omitted, and a solenoid valve that only opens and closes the conduit 37a is provided in the conduit 37a. And the tilt cylinder 9
When the operation of the tilt cylinder 9 is required, the solenoid valve is kept open, and when the operation of the tilt cylinder 9 is unnecessary, the solenoid valve is kept closed. When the tilt angle θ of the mast 3 reaches the maximum allowable tilt angle θx during the tilting operation of the tilt cylinder 9, the solenoid valve is switched from the open state to the closed state by a command from the control device 49. In this configuration, instead of the control valve 38 and the proportional solenoid valve 43 operated by the pilot pressure, the forward tilt angle can be regulated by a simple on / off solenoid valve.

The mast angle detecting means may be any as long as it can detect the tilt angle θ of the mast 3 from the reference position, and is not limited to the rotary potentiometer 15 for detecting the rotation angle of the tilt cylinder 9; A linear potentiometer that detects the amount of expansion and contraction of the tilt cylinder 9, that is, the amount of protrusion of the piston rod 9a may be used. Further, the rotation angle of the shaft that rotates together with the mast 3 may be detected by a potentiometer or a rotary encoder. still,
In the present embodiment, the reference position is a position where the mast 3 is vertical, but any reference position may be used as long as data or the like stored in the EEPROM 54b is made to correspond.

In place of the map representing the relationship between the load w and the maximum allowable forward tilt angle θx as data necessary for executing the forward tilt angle restriction control program of the above embodiment, the load w and the maximum allowable forward tilt angle θx are replaced. The equation expressing the relationship with the inclination angle θx is expressed as EEP
It may be stored in the ROM 54b. Also, EEPROM5
The data stored in 4b may be stored in ROM 54a. In this case, the EEPROM 54b can be omitted. Further, the data stored in the EEPROM 54b may be stored in a RAM or a flash memory having a power supply for backup. In this case, correction of the map or the relational expression becomes easy.

In the above embodiment, the maximum allowable forward tilt angle θx is a value between 6 ° and 2 ° with the reference position set to 0 °, but may be changed as necessary. ○ Attachments other than the fork 6 as cargo handling attachments, such as roll clamps used for transporting roll paper, block clamps used for transporting blocks and high-loading work, coiled or cylindrical coils and wires such as coils and wires. The present invention may be applied to an industrial vehicle equipped with a ram or the like used for carrying cargo.

The present invention is not limited to an industrial vehicle using an engine as a driving source, but may be applied to an industrial vehicle using a battery as a driving source. In the above-described embodiment, the tilting operation at the time of the forward tilting operation is restricted, but the tilting operation at the time of the backward tilting operation may be similarly restricted. In this case, the mast does not lean backward beyond the maximum allowable backward tilt angle at that time even if the backward leaning operation is performed during backward high-speed reverse travel,
In other words, since the position of the center of gravity does not move further backward,
Even if the inertial force according to the traveling speed acts rearward, the front wheels 16 are prevented from floating and slipping is prevented from occurring.

Further, in a special forklift having a high mast, the rearward inclination angle is made smaller than that of a normal forklift in consideration of stability at a high elevation. However, when the load is transported at a low lift, the stability increases when the load is tilted to the backward tilt angle similar to that of a normal forklift. Therefore, in such a case, a rearward tilting angle restriction function may be provided to restrict the rearward tilting angle at a high elevation, so that the rearward tilting angle at a low elevation can be increased.

The technical ideas (inventions) other than those described in the claims that can be grasped from the embodiment will be described below together with their effects. The industrial vehicle tilt cylinder control device according to any one of claims 1 to 6, wherein the maximum allowable tilt angle is a maximum allowable forward tilt angle when the mast is tilted toward the front side. Cylinder control device.

In this way, the rear wheels of the forklift 1 do not rise or collapse.

[0078]

As described above in detail, according to the first aspect of the present invention, even if the tilting operation is performed during traveling, there is no possibility that the collapse of the load or the lifting of the wheels occurs.

According to the second aspect of the present invention, even if the tilting operation is performed during traveling, the position of the center of gravity at that time is taken into consideration, and there is no possibility that the collapse of the load or the lifting of the wheels occurs. According to the third aspect of the present invention, even if the tilting operation is performed during traveling under a high load, there is no possibility that the load collapses or the wheels are lifted.

According to the fourth aspect of the present invention, even if the tilting operation is performed while the vehicle is traveling at a high elevation, there is no risk of collapse of the load or lifting of the wheels. According to the fifth aspect of the present invention, even if the tilting operation is performed during traveling under a high load and a high lift, there is no possibility that the load collapses or the wheels are lifted.

According to the sixth aspect of the present invention, it is possible to reliably prevent the mast from tilting more than the maximum allowable tilt angle corresponding to the change in the traveling speed and the position of the center of gravity during the tilting operation of the mast.

According to the seventh aspect of the present invention, during the tilting operation of the mast, the mast is reliably prevented from tilting more than the maximum allowable tilt angle corresponding to the traveling speed and the load.

According to the eighth aspect of the present invention, it is possible to reliably prevent the mast from tilting more than the maximum allowable tilt angle corresponding to the traveling speed and the lift during the tilting operation of the mast.

According to the ninth aspect of the present invention, the mast is reliably prevented from tilting more than the maximum allowable tilt angle corresponding to the load, the lift and the traveling speed. According to the tenth aspect of the present invention, in a state where the manual operation direction switching valve is switched to the operation position for tilting the mast and the tilt cylinder is operated to tilt the mast, the mast angle is set to the maximum allowable tilt. When the angle is reached, the solenoid valve is controlled by the control means into a line cutoff state. Therefore, even if the manual operation direction switching valve is held at the operating position for tilting the mast, the operation of the tilt cylinder is stopped, and the mast is held at the predetermined maximum allowable tilt angle.

[Brief description of the drawings]

FIG. 1 is a hydraulic circuit diagram according to an embodiment.

FIG. 2 is a block diagram showing an electrical configuration of the control device.

FIG. 3 is a side view of the forklift.

FIG. 4 is a side view of a tilt operation lever.

FIG. 5 is a flowchart of a forward lean angle restriction control process according to the embodiment.

FIG. 6 is a map diagram for a forward tilt angle restriction control process according to the embodiment.

FIG. 7 is a map diagram for a forward lean angle restriction control process in another example.

[Explanation of symbols]

1: Forklift as an industrial vehicle, 3: Mast, 6
... Fork as cargo handling attachment, 9. Tilt cylinder, 14... Lift sensor as center of gravity position detecting means and height detecting means, 15. Potentiometer as mast angle detecting means, 17. A pressure sensor as a means, 23 a calculation drive control means and a tilt control valve as a manual operation direction switching valve constituting the drive control means, 37a a pipeline, 38 a calculation drive control means, a drive control means and an electromagnetic valve. Constituting control valve, 43 ... Calculation drive control means, proportional solenoid valve forming drive control means and electromagnetic valve, 49 ... Drive control device forming drive control means and drive control means, 53 ... Constituting calculation drive control means A central processing unit (CPU) as arithmetic means, and 54b an EEPROM as storage means;
S: vehicle speed sensor as vehicle speed detecting means, V: running speed (vehicle speed), θ: tilt angle, w: loading load (load), H:
Lift, θx: Maximum allowable forward tilt angle as maximum allowable tilt angle.

Claims (10)

[Claims] 1. An industrial vehicle in which a mast for lifting and lowering an attachment for cargo handling is tiltably provided and the mast is tilted by actuation of a tilt cylinder, wherein a maximum allowable tilt angle of the mast corresponds to a traveling speed of the industrial vehicle. A tilt cylinder control device for an industrial vehicle, comprising arithmetic drive control means for controlling supply of hydraulic oil to the tilt cylinder so as to change the tilt cylinder. 2. The tilt cylinder control of an industrial vehicle according to claim 1, wherein the arithmetic drive control means changes the maximum allowable tilt angle in accordance with a position of a center of gravity in addition to a traveling speed of the industrial vehicle. apparatus. 3. The industrial apparatus according to claim 1, wherein the arithmetic drive control means changes the maximum allowable tilt angle in accordance with a load of the cargo handling attachment in addition to a traveling speed of the industrial vehicle. Vehicle tilt cylinder control device. 4. The industrial apparatus according to claim 1, wherein the arithmetic drive control means changes the maximum allowable tilt angle in accordance with a height of the cargo handling attachment in addition to a traveling speed of the industrial vehicle. Vehicle tilt cylinder control device. 5. The method according to claim 1, wherein the calculating drive control means changes the maximum allowable tilt angle in accordance with a lifting height of the cargo handling attachment and a load of the cargo handling attachment in addition to a traveling speed of the industrial vehicle. The tilt cylinder control device for an industrial vehicle according to claim 1. 6. An industrial vehicle in which a mast for raising and lowering a cargo handling attachment is tiltably provided, and wherein the mast is tilted by actuation of a tilt cylinder, a vehicle speed detecting means for detecting a traveling speed of the industrial vehicle; A center-of-gravity position detecting means for detecting a center-of-gravity position of the vehicle; a mast angle detecting means for detecting a tilt angle of the mast from a reference position; and storage for storing data for deriving a maximum permissible tilt angle for the traveling speed and the center-of-gravity position. Means, calculating means for calculating the maximum allowable tilt angle of the mast at that time based on the traveling speed detected by the vehicle speed detecting means and the position of the center of gravity detected by the center of gravity position detecting means, and when the mast is tilted. When the tilt cylinder is operated, the tilt angle detected by the mast angle detecting means is calculated by the calculating means. A tilt cylinder control device for an industrial vehicle, comprising: drive control means for controlling supply of hydraulic oil to the tilt cylinder so as to stop the tilting operation of the mast when the calculated maximum allowable tilt angle is reached. 7. The industrial vehicle tilt cylinder control device according to claim 6, wherein the center-of-gravity position detecting means is a loading load detecting means for detecting a loading load of the cargo handling attachment. Tilt cylinder control device. 8. The industrial vehicle tilt cylinder control device according to claim 6, wherein the center-of-gravity position detecting means is a height detecting means for detecting a height of the cargo handling attachment. Tilt cylinder control device. 9. The tilt cylinder control device for an industrial vehicle according to claim 6, wherein the center-of-gravity position detecting means detects a loading load of the loading attachment and a lift of the loading attachment. A tilt cylinder control device for an industrial vehicle, comprising: 10. A drive control means for controlling the supply of hydraulic oil to the tilt cylinder includes a manual operation direction switching valve for switching between supply and discharge of hydraulic oil to the tilt cylinder; When the mast angle reaches a predetermined angle during operation of the tilt cylinder when tilting the mast, the solenoid valve is provided in the middle of the pipeline connecting the tilt cylinder and shuts off the pipeline. The tilt cylinder control device for an industrial vehicle according to any one of claims 6 to 9, further comprising a drive control device that controls the state of the vehicle.