JP4687237B2 - Industrial vehicle cargo handling control device - Google Patents

Description

The present invention relates to a cargo control equipment for industrial vehicles each supply battery forklift or the like diverted to the cargo handling control device and the hydraulic power steering system hydraulic oil from a hydraulic pump driven by a hydraulic motor of the electric Is.

  2. Description of the Related Art Conventionally, hydraulic control devices for industrial vehicles such as battery-type forklifts that supply hydraulic oil from a hydraulic pump driven by an electric hydraulic motor to a cargo handling control device and a hydraulic power steering device have been proposed. (See Patent Document 1).

In order to reduce the number of motors, reduce costs, further reduce noise, and realize energy saving, the load handling pump of the load handling apparatus rotated by the electric motor driven by the chopper is replaced with the hydraulic pump of the power steering apparatus. In addition, the discharged hydraulic oil is supplied to the steering control valve and the cargo handling device via a flow divider with load sensing.
Japanese Utility Model Publication No. 5-5658

  By the way, when the flow rate of hydraulic oil supplied to the cargo handling control device is made variable by changing the rotation speed of the electric motor for driving the cargo handling pump by chopper driving according to the operation amount of the cargo handling lever as in the above conventional example. The cargo handling work can be performed without being related to the traveling state of the vehicle. For this reason, since the vehicle posture becomes unstable depending on the traveling state during the cargo handling operation, the operator is instructed to travel at a reduced vehicle speed during the cargo handling operation. However, the extent to which the vehicle posture becomes unstable from the running state and the cargo handling state differs depending on the vehicle type (tread and wheelbase) and the type of cargo handling work.

The present invention has been made in view of the above problems, and an object thereof is to provide a cargo handling control equipment suitable industrial vehicle for stabilization of the vehicle posture.

The present invention is configured to supply hydraulic oil discharged from a hydraulic pump driven by an electric hydraulic motor to a cargo handling control valve of the cargo handling device, and when the cargo handling device is not operated, Control means for increasing the number of rotations of the hydraulic motor in accordance with the amount of operation of the cargo handling device when the cargo handling device is operated with the rotation stopped or idle, and the vehicle traveling speed by the control means When the vehicle is traveling backward , the upper limit value of the hydraulic motor is set higher in the low speed region of the vehicle. When the preset traveling speed is exceeded, the rotational speed of the hydraulic motor is set to zero or an idle rotational speed close to zero .

Accordingly, in the present invention, hydraulic oil of a hydraulic pump driven by an electric hydraulic motor is configured to be supplied to the cargo handling control valve of the cargo handling device, and when the cargo handling device is not operated, the hydraulic motor is rotated. When the cargo handling device is operated in a stopped or idle rotation state, the rotational speed of the hydraulic motor is increased according to the operation amount of the cargo handling device, and the hydraulic motor is Since control is performed to reduce the upper limit value of the rotational speed, the cargo handling operation speed is regulated to decrease as the traveling speed increases, so that the vehicle posture can be prevented from becoming unstable and wasteful power consumption is suppressed. it can.
In addition, when the vehicle is traveling backward, the upper limit value of the rotational speed of the hydraulic motor is set high in the low speed range of the vehicle traveling speed, and when the traveling speed exceeds a preset traveling speed, By setting the rotation speed to zero or an idle rotation speed close to zero, it is possible to improve the safety of cargo handling operations in the cargo handling operation area due to low-speed reverse travel and the prohibition of cargo handling operations due to malfunctions in medium-high speed reverse travel it can.

  Hereinafter, an embodiment of an industrial vehicle cargo handling control apparatus according to the present invention will be described with reference to FIGS.

  1 to 2 are a plan view and a side view showing an external appearance of a battery forklift that is an industrial vehicle to which the present invention is applied.

  The battery forklift has a four-wheel configuration having a pair of left and right drive wheels 2 at the front of the vehicle body 1 and a pair of left and right steering wheels 3 at the rear. The left and right drive wheels 2 are respectively driven by a travel motor including a left wheel drive motor and a right wheel drive motor (not shown). The steered wheels 3 are disposed below the counterweight 4. A mast device 5 as a cargo handling device for transporting a load is provided in front of the left and right drive wheels 2, and a driver seat 6 is provided between the left and right drive wheels 2 and the rear steering wheel 3. The driver's seat 6 includes a steering wheel 7, a cargo handling lever 8 (tilt lever and lift lever) operated when the mast device 5 is tilted and raised, a forward / reverse lever 9 for selecting a traveling direction, and an accelerator pedal (not shown). In addition, a brake pedal and the like are provided. The forward / reverse lever 9 can be switched between three positions: forward, neutral and reverse.

  FIG. 3 is a system configuration diagram showing the configuration of the main part of the hydraulic control device for the battery forklift, and FIG. 4 is a diagram showing the configuration of the control unit of FIG.

  The hydraulic pump 10 supplies hydraulic oil via a priority flow rate control valve 14 to the hydraulic mechanism of the power steering device 13 and the hydraulic mechanism of the mast device 5 that performs cargo handling. Driven. The hydraulic motor 11 controls the flow rate of the hydraulic oil supplied from the hydraulic pump 10 to each hydraulic mechanism by controlling the operation of the hydraulic pump 10.

  The priority flow control valve 14 is a valve that supplies hydraulic oil with priority over the hydraulic mechanism of the power steering device 13, supplies hydraulic oil required by the steering control valve 15 with priority, and handles the remaining hydraulic oil. The cargo is supplied to the cargo handling cylinder 17 under the control of the control valve 16.

  The steering control valve 15 supplies hydraulic oil corresponding to the left and right steering angular velocities of the steering wheel 7 to the steering cylinder 18. The steering cylinder 18 is operated by hydraulic oil supplied from the steering control valve 15 while distinguishing the steering direction, and steers the steering wheel 3 to the right or left. The steering angle sensor 19 is configured by a potentiometer or the like provided on the rotation shaft of the steering wheel 7, detects the rotation angle of the steering wheel 7, and outputs the detected rotation angle signal to the control unit 12.

  The hydraulic mechanism of the mast device 5 that performs loading / unloading includes a loading / unloading control valve 16 that receives supply of hydraulic oil diverted from the priority flow rate control valve 14 and controls supply / discharge of hydraulic fluid to / from the loading cylinder 17 of the mast device 5. . In the forklift as an industrial vehicle, the cargo handling control valve 16 includes a tilt control valve that controls a tilt cylinder as the cargo handling cylinder 17 and a lift control valve that controls the lift cylinder of the cargo handling cylinder, both of which are switched by the cargo handling lever 8. Operated. Either the tilt control valve or the lift control valve as the cargo handling control valve 16 may be arranged upstream. Between the cargo handling control valve 16 and the cargo handling cylinder 17, a shutoff valve 21 capable of shutting off the flow of hydraulic oil between the two is disposed, and is controlled to be opened and closed by the control unit 12. The hydraulic oil discharged from the steering control valve 15 and the cargo handling control valve 16 is returned to the hydraulic oil tank 20 and sucked by the hydraulic pump 10 again.

  As shown in FIG. 4, the control unit 12 includes a CPU 23, a RAM 24, a ROM 25 storing a motor control program and the like, and an input / output unit (I / O) 26. An input / output unit 26 of the control unit 12 includes a control signal A indicating the angle of the steering wheel 7 from the steering angle sensor 19, an operation signal B of the cargo handling lever 8, a rotation speed signal C of the hydraulic motor 11, and a travel motor rotation sensor 22. The rotation speed signal D and the like are input.

  Further, the CPU 23 of the control unit 12 obtains an angular velocity A1 from the angle signal A of the steering wheel 7 detected by the steering angle sensor 19, and according to the angular velocity A1 and the operation signal B of the cargo handling operation lever 8, the hydraulic motor 11 A control signal E for controlling the number of rotations is output to the hydraulic motor 11 via the input / output unit 26. Specifically, as shown in FIG. 5, while obtaining the hydraulic motor rotational speed A2 to the power steering device that secures the hydraulic oil flow rate required for the operation of the power steering device 13 based on the steering angular velocity signal A1, As shown in FIG. 6, a hydraulic motor rotational speed B <b> 1 to the cargo handling device 5 that secures the hydraulic oil flow rate necessary for the operation of the cargo handling device 5 is obtained based on the operation amount signal B of the cargo handling lever. And the control signal E which controls the hydraulic motor 11 is output so that it may become the rotation speed (A2 + B1) which added both rotation speed A2 and B1.

  The upper limit of the rotational speed B1 of the hydraulic motor to the cargo handling device 5 is limited based on the traveling motor rotational speed signal D. That is, when the limit by the traveling motor rotation speed signal D is not added, as shown by the solid line in FIG. 6, the cargo handling device 5 can operate at a sufficient speed, for example, up to about 2500 to 3000 [rpm]. The rotation speed Bmax corresponding to the operation amount B of the cargo handling lever 8 is selected. However, when it is determined that the vehicle is traveling at a medium to high speed, for example, 10 [km / h] or more, as shown by a broken line, the rotational speed at which the operation of the cargo handling device 5 is limited, for example, 750 The rotation speed Bmin corresponding to the operation amount B of the cargo handling lever 8 with the upper limit up to [rpm] is selected. The switching of the rotational speed from Bmax to Bmin is performed when the vehicle shifts to a medium speed state. For example, the upper limit of the rotational speed is gradually increased as the traveling speed increases from the time when the vehicle speed exceeds 5 km / h. This is done by lowering the value.

  In addition, when it can be determined that the vehicle is traveling backward by the traveling motor rotational speed signal D, it is determined that the vehicle has shifted to the medium speed traveling, for example, 7.5 [km / h] ], The rotational speed of the hydraulic motor 11 to the cargo handling device 5 is set to zero so that the operation of the cargo handling device 5 is prohibited, as shown by the chain line. Further, based on the traveling motor rotation speed signal D and the operation signal B of the cargo handling lever 8, a command F for operating the shut-off valve 21 that prohibits the operation of the cargo handling device 5 is output. Even if the hydraulic oil is not supplied to the cargo handling device 5, the shut-off valve 21 lowers the fork of the mast device 5 by removing the hydraulic oil in the cylinder like the lift cylinder of the mast device 5. The lowering prohibition solenoid valve that prohibits the operation of the cargo handling device 5 is selected.

  The controller 12 operates based on the flowchart shown in FIG. The flowchart shown in FIG. 7 is executed by the control unit 12 every predetermined time. FIG. 8 is a characteristic diagram showing a change in the upper limit value of the hydraulic motor rotational speed with respect to the traveling speed of the vehicle. The solid line is the upper limit value of the hydraulic motor rotational speed to the cargo handling device 5, and the broken line is the cargo handling device 5. The upper limit value of the hydraulic motor rotation speed to the power steering device 13 is added to the upper limit value of the hydraulic motor rotation speed to. Hereinafter, the control operation executed by the control unit 12 will be described with reference to FIGS.

  First, in step S1, the controller 12 controls the steering angular velocity signal A1 based on the steering angle sensor 19, the operation signal B of the cargo handling lever 8, the rotational speed signal C of the hydraulic motor 11, and the rotational speed signal from the traveling motor rotational sensor 22. Each signal of D is read, and the process proceeds to step S2.

  In step S2, it is determined whether or not the cargo handling lever 8 is operated based on the cargo handling lever operation signal B. If the cargo handling lever 8 is not operated, the process proceeds to step S3, and the hydraulic motor rotational speed is determined as the steering angular velocity signal. Control based only on A1. FIG. 8 does not show a state in which only the power steering device 13 is activated. Most of the hydraulic oil from the hydraulic pump 10 is supplied to the steering control valve 15 of the power steering device 13 by the priority flow control valve 14, and supplied to the steering cylinder 18 based on the steering direction of the steering wheel 7, and the steering wheel 3. Steer. In this case, the steering wheel 3 is steered in accordance with the steering motor speed signal D, that is, the steering angular velocity A1 of the steering wheel 7 regardless of the traveling state of the vehicle, and steers the vehicle in a necessary direction. be able to. Further, if the cargo handling lever 8 is operated in the determination in step S2, the process proceeds to step S4.

In step S4, the rotational direction of the traveling motor is determined based on the traveling motor rotational speed signal D. If the vehicle is in the forward traveling state, the process proceeds to step S5, where the hydraulic motor rotational speed is converted to the steering angular speed signal A1 and the cargo handling lever operation signal. Control is performed based on both of B and B. In this case, as shown in FIG. 5, while obtaining the hydraulic motor rotational speed A2 to the power steering device 13 that secures the hydraulic oil flow rate necessary for the operation of the power steering device 13 based on the steering angular velocity signal A1, As shown in FIG. 6, the hydraulic motor rotation speed B <b> 1 to the cargo handling device 5 that secures the hydraulic oil flow rate necessary for the operation of the cargo handling device 5 is obtained based on the operation amount signal B of the cargo handling lever 8. And the control signal E which controls the hydraulic motor 11 is output so that it may become the rotation speed (A2 + B1) which added both rotation speed A2 and B1. Further, when the traveling motor rotational speed signal D is in the low speed traveling state, the upper limit of the hydraulic motor rotational speed B1 to the cargo handling device 5 is set to Bmax, but when the traveling speed is shifted to the medium speed state, The upper limit of the hydraulic motor rotation speed B1 to the cargo handling device 5 is set between Bmax and Bmin, and when the medium speed state is exceeded, the upper limit of the hydraulic motor rotation speed B1 to the cargo handling device 5 is Bmin. Is set. FIG. 8 shows a change in the upper limit value of the hydraulic motor rotation speed B1 when the vehicle speed is increased from 0 to the traveling speed in the forward direction.

  The hydraulic oil from the hydraulic pump 10 is supplied to the steering control valve 15 of the power steering device 13 by the priority flow rate control valve 14 for the rotational speed A2 corresponding to the steering angular speed A1, and based on the steering direction of the steering wheel 7. Supplyed to the steering cylinder 18, the steered wheels 3 are steered. Further, the remaining hydraulic oil is supplied to the cargo handling control valve 16 of the cargo handling device 5 and is supplied to the cargo handling cylinder 17 according to the operation amount B of the cargo handling lever 8, and the cargo handling device 5 is made to correspond to the operation amount B of the cargo handling lever 8. Operate at operating speed. In this case, the steering wheel 3 is steered according to the steering angular velocity A1 of the steering wheel 7, and the operating speed of the cargo handling device 5 is changed according to the traveling motor rotation speed signal D, that is, the traveling state of the vehicle. . On the other hand, if it is determined in step S4 that the rotation direction of the travel motor is in the reverse drive state of the vehicle, the process proceeds to step S6.

  In step S6, it is determined based on the traveling motor rotation speed signal D whether the reverse speed of the vehicle is equal to or higher than a preset speed VB. When the reverse speed does not exceed the set speed VB, the process proceeds to step S7, and when it is equal to or higher than the set speed VB, the process proceeds to step S8.

In step S7, since the reverse speed is a low speed traveling state less than the set speed VB, the hydraulic motor rotation speed A2 is controlled based on both the steering angular speed signal A1 and the cargo handling lever operation signal B. In this case, as shown in FIG. 5, while obtaining the hydraulic motor rotational speed A2 to the power steering device 13 that secures the hydraulic oil flow rate necessary for the operation of the power steering device 13 based on the steering angular velocity signal A1, As shown in FIG. 6, the hydraulic motor rotation speed B <b> 1 to the cargo handling device 5 that secures the hydraulic oil flow rate necessary for the operation of the cargo handling device 5 is obtained based on the operation amount signal B of the cargo handling lever 8. And the control signal E which controls the hydraulic motor 11 is output so that it may become the rotation speed (A2 + B1) which added both rotation speed A2 and B1. Since the vehicle in this case is in a low-speed traveling state, the upper limit of the hydraulic motor rotation speed B1 to the cargo handling device 5 is set to Bmax. FIG. 8 shows the change of the upper limit value of the hydraulic motor rotation speed B1 when the vehicle speed is increased from 0 to the reverse travel direction, and the hydraulic pressure in the state where the vehicle speed is less than the set speed VB is shown. The upper limit value of the motor rotation speed B1 is also shown.

  The hydraulic oil from the hydraulic pump 10 is supplied to the steering control valve 15 of the power steering device 13 by the priority flow rate control valve 14 for the rotational speed A2 corresponding to the steering angular speed A1, and based on the steering direction of the steering wheel 7. Supplyed to the steering cylinder 18, the steered wheels 3 are steered. Further, the remaining hydraulic oil is supplied to the cargo handling control valve 16 of the cargo handling device 5 and is supplied to the cargo handling cylinder 17 according to the operation amount B of the cargo handling lever 8, and the cargo handling device 5 is made to correspond to the operation amount B of the cargo handling lever 8. Operate at operating speed.

  In step S8, since the reverse speed is a medium-high speed traveling state that is equal to or higher than the set speed VB, the hydraulic motor rotation speed is controlled based only on the steering angular speed signal A1, and the cargo handling device 5 is operated regardless of whether the cargo handling lever 8 is operated or not. Is controlled so as to be prohibited (see the characteristic of the vehicle speed equal to or higher than the set vehicle speed VB in FIG. 8). Most of the hydraulic oil from the hydraulic pump 10 is supplied to the steering control valve 15 of the power steering device 13 by the priority flow rate control valve 14 as in step S3, and the steering cylinder 18 is based on the steering direction of the steering wheel 7. To steer the steerable wheels 3. In this case, the steering wheel 3 is steered in accordance with the steering motor speed signal D, that is, the steering angular velocity A1 of the steering wheel 7 regardless of the traveling state of the vehicle, and steers the vehicle in a necessary direction. be able to. Moreover, since the control part 12 outputs the cutoff signal F of the cutoff valve 21, and the cutoff valve 21 closes, the handling cylinder 17 will be in a hydraulic lock state, and the cargo handling apparatus 5 will be inactive.

  In the above embodiment, the hydraulic oil supplied from the hydraulic pump 10 via the priority flow rate control valve 14 by the steering control valve 15 that operates by steering the steering wheel 7 as the power steering device 13 depends on the steering speed. The description has been made on the target for the all-hydraulic power steering device 13 known in Japanese Patent No. 2645515 or Japanese Patent Application Laid-Open No. 2004-196110 that supplies the steering cylinder 18 with a different flow rate. Although not shown, the hydraulic oil supplied from the hydraulic pump 10 via the priority flow rate control valve 14 is steered by distinguishing the steering direction according to the relative relationship between the steering wheel 7 and the steering cylinder feedback position. Shi Hydraulic power steering system generally supplied to Sunda or may be directed to.

  In the above embodiment, the hydraulic fluid from the hydraulic pump 10 is divided into the power steering device 13 and the cargo handling device 5 by the priority flow rate control valve 14, but although not shown, the hydraulic fluid is operated to the power steering device. A cargo handling control device that directly supplies hydraulic oil from the hydraulic pump 10 to the cargo handling device 5 without supplying oil may be used.

  In the present embodiment, the following effects can be achieved.

  (A) The hydraulic fluid discharged from the hydraulic pump 10 driven by the electric hydraulic motor 11 is supplied to the cargo handling control valve 16 of the cargo handling device 5, and when the cargo handling device 5 is not operated, Control means 12 is provided for stopping the rotation of the hydraulic motor 11 or setting it in an idle rotation state and increasing the rotational speed of the hydraulic motor 11 in accordance with the operation amount of the cargo handling apparatus 5 when the cargo handling apparatus 5 is being operated. Since the control means 12 controls to lower the upper limit value of the rotational speed of the hydraulic motor 11 in accordance with an increase in the traveling speed of the vehicle, the cargo handling operation speed is regulated to decrease as the traveling speed increases. The vehicle posture can be prevented from becoming unstable, and wasteful power consumption can be suppressed.

  (A) As a cargo handling device 5, a lift cylinder as a hydraulic lifting / lowering means 17 for lifting and lowering a load to be loaded is provided, and the supply / discharge speed of hydraulic oil to / from the hydraulic lifting / lowering means 17 is controlled by the operation amount of the cargo handling lever 8. In addition, the vertical movement speed of the load can be lowered during medium to high speed traveling, and the stability of the vehicle posture can be improved.

  (C) As the control means 12, when the vehicle is traveling forward, the upper limit value of the number of revolutions of the hydraulic motor 11 is set high in the low speed range of the vehicle traveling speed, and the hydraulic motor 11 is set in the medium high speed range. In addition, the upper limit value of the rotational speed of the hydraulic motor 11 between the low speed range and the medium / high speed range of the vehicle travel speed is decreased as the travel speed increases. Therefore, it is possible to achieve both the handling workability in the handling operation area by low-speed traveling and the transfer workability in the transportation area by medium-high speed traveling, and in addition, the transition between both areas can be facilitated.

  (D) When the vehicle is traveling backward as the control means 12, the upper limit value of the rotational speed of the hydraulic motor 11 is set high in the low speed range of the vehicle traveling speed, and exceeds the preset traveling speed. By setting the rotational speed of the hydraulic motor 11 to zero or an idle rotational speed close to zero, the cargo handling workability in the cargo handling operation region due to low speed reverse travel and the safety due to the prohibition of cargo handling operation due to malfunction during medium and high speed reverse travel It is possible to improve the performance.

(E) When the shut-off valve 21 for shutting off the supply and discharge of the hydraulic oil to the cargo handling cylinder 17 of the cargo handling device 5 is provided, the control means 12 causes the reverse travel speed of the vehicle to exceed the preset travel speed. If the shut-off valve 21 is operated, the effect (d) can be further improved.

  (F) A hydraulic power steering device 13 for turning the steered wheels 3 by supplying the introduced hydraulic oil to the left and right steering cylinders 18 in accordance with the steering operation of the steering wheel 7 is driven by the hydraulic motor 11. The hydraulic oil discharged from the hydraulic pump 10 is supplied to the hydraulic power steering device 13 with the priority flow rate control valve 14 being preferentially divided and supplied, and the remaining operation is supplied to the cargo handling control valve 16 of the cargo handling device 5. When the hydraulic power steering device 13 is not operated by the control means 12, the rotational speed of the hydraulic motor 11 is determined by the operation amount of the cargo handling device 5 and the vehicle traveling speed. When the hydraulic power steering device 13 is operated with the set number of rotations, the operation amount of the cargo handling device 5 and the vehicle When the rotational speed of the hydraulic motor 11 is set by adding the rotational speed that secures the flow rate of the hydraulic oil consumed by the hydraulic power steering device 13 to the rotational speed set by the traveling speed, the power steering device 13 and the cargo handling device The power consumption in the hydraulic oil supply to 5 can be suppressed.

The top view of the battery forklift which is an industrial vehicle to which one Embodiment of this invention is applied. The side view of the battery forklift which is also an industrial vehicle. The system block diagram which shows the structure of the principal part regarding the hydraulic control apparatus of a battery forklift. The figure which shows the structure of the control part of FIG. The characteristic view which shows the motor rotation speed for hydraulics for the hydraulic fluid supply to a power steering apparatus. The characteristic view which shows the motor rotation speed for the hydraulics for the hydraulic fluid supply to a cargo handling apparatus. The flowchart performed by the control part for every predetermined time. The characteristic view which shows the change of the upper limit of the hydraulic motor rotation speed with respect to the running speed of a vehicle.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Car body 2 Driving wheel 3 Steering wheel 4 Counterweight 5 Mast device as a cargo handling device 6 Driver's seat 7 Steering wheel 8 Cargo handling lever 9 Forward / reverse lever 10 Hydraulic pump 11 Hydraulic motor 12 Control part 13 as a control means 13 Power steering device 14 Priority flow control valve 15 Steering control valve 16 Cargo handling control valve 17 Cargo handling cylinder 18 Steering cylinder 21 Shut-off valve

Claims (5)

It is configured to supply hydraulic oil discharged from a hydraulic pump driven by an electric hydraulic motor to a cargo handling control valve of the cargo handling device, and when the cargo handling device is not operated, the rotation of the hydraulic motor is stopped or In an industrial vehicle cargo handling control device comprising control means for increasing the number of rotations of the hydraulic motor according to the operation amount of the cargo handling device when the cargo handling device is operated in an idle rotation state,
The control means controls to lower the upper limit value of the number of rotations of the hydraulic motor according to an increase in the traveling speed of the vehicle, and when the vehicle is traveling backward, in the low speed region of the vehicle traveling speed, An industrial vehicle characterized in that the upper limit value of the number of rotations of the hydraulic motor is set high and the number of rotations of the hydraulic motor is set to zero or an idle rotation number close to zero when a predetermined traveling speed is exceeded. Cargo handling control device. A shut-off valve that shuts off the supply and discharge of hydraulic oil to and from the cargo handling cylinder of the cargo handling device;
2. The industrial vehicle cargo handling control device according to claim 1, wherein the control means operates the shut-off valve when a reverse travel speed of the vehicle exceeds the preset travel speed .   When the vehicle is traveling forward, the control means sets a high upper limit value of the hydraulic motor rotation speed in a low speed range of the vehicle travel speed, and an upper limit of the hydraulic motor rotation speed in a medium high speed range. The cargo handling control device for an industrial vehicle according to claim 1 or 2, wherein the value is set low.   The said control means is set so that the upper limit of the rotation speed of the said hydraulic motor between the low speed area | region of a vehicle travel speed and a medium-high speed area may be reduced with the increase in a travel speed. An industrial vehicle cargo handling control device according to claim 1. A hydraulic power steering device for turning the steered wheels by supplying the introduced hydraulic oil to the left and right steering cylinders according to the steering operation of the steering wheel,
The hydraulic fluid discharged from the hydraulic pump driven by the hydraulic motor is supplied with a priority flow control valve by preferentially diverting the hydraulic fluid to the hydraulic power steering device, and the remaining hydraulic fluid is supplied to the cargo handling control valve of the cargo handling device. It is configured to supply hydraulic oil in a divided flow,
When the hydraulic power steering device is not operated, the control means sets the rotational speed of the hydraulic motor to a rotational speed set by the operation amount of the cargo handling device and the vehicle traveling speed, and the hydraulic power steering device is operated. The number of revolutions of the hydraulic motor by adding the number of revolutions that secures the flow rate of the hydraulic oil consumed by the hydraulic power steering device to the number of revolutions set by the operation amount of the cargo handling device and the vehicle traveling speed. The cargo handling control device for an industrial vehicle according to any one of claims 1 to 4, wherein:

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