JP2007039226A - Hydraulic system of industrial vehicle - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To restrain unnecessary restriction on operation of a hydraulic device of the other function by restricting the occurrence of an unprepared operation state of a cargo handling device with a simple constitution in a seat leaving state. <P>SOLUTION: The cargo handling devices 11 and 12 perform cargo handling operation by being driven by pressure oil supplied from a pump 32. The hydraulic device of the other function includes a steering device 33 performing steering operation and a braking device 34 performing braking operation by being driven by the pressure oil supplied from the pump 32. An occupant detecting means 51 detects whether or not an occupant operating an industrial vehicle 10 sits down on a driver's seat 21. A supply quantity restricting means 52 restricts a supply quantity of the pressure oil to the cargo handling devices 11 and 12 from the pump 32 when detecting the seat leaving state by the occupant detecting means 51. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a hydraulic system for an industrial vehicle including a hydraulic device driven by pressure oil supplied from a pump.

  Industrial vehicles such as forklifts are provided with a hydraulic system having a pump and a hydraulic device driven by pressure oil supplied from the pump. As a hydraulic system for such an industrial vehicle, a forklift is provided with a solenoid valve provided between a lift control valve and a lift cylinder, and this solenoid valve is operated by a switch that opens and closes according to the weight of a passenger who operates the forklift. The thing provided with a structure is known (refer patent document 1). In the hydraulic system described in Patent Document 1, when the occupant leaves the driver's seat, the switch is closed and the solenoid valve is switched, the hydraulic circuit between the lift control valve and the lift cylinder is shut off, and the pressure oil from the pump Is discharged into the tank. This prevents the lift cylinder from operating even if there is an inadvertent operation by another person.

Japanese Utility Model Publication No. 60-114194

However, in the industrial vehicle hydraulic system described in Patent Document 1, it is necessary to provide an electromagnetic valve for shutting off the hydraulic circuit so that the lift cylinder does not operate when the occupant leaves the seat. When a tilt cylinder or other cargo handling cylinder is provided in addition to the lift cylinder, it is necessary to provide a similar solenoid valve for each cylinder, which complicates the mechanism.
Further, as a configuration in which a cargo handling cylinder such as a lift cylinder is not operated, it is conceivable to stop the supply of pressure oil by stopping the pump. However, in an industrial vehicle, as a hydraulic device driven by pressure oil supplied from a pump, in general, not only a cargo handling device that performs a cargo handling operation like a lift device, but also a hydraulic device of another function in an industrial vehicle. A steering device for performing a steering operation and a braking device for performing a braking operation are also provided. When these other hydraulic devices are driven by pressure oil supplied from the same pump as a cargo handling cylinder such as a lift cylinder, the supply of pressure oil from the pump is stopped when the occupant leaves the driver's seat. Therefore, during the absence state, the pressure oil from the pump is not supplied to the steering device or the braking device, and during this time, the steering device or the braking device cannot be operated to obtain the necessary steering force or braking force. There is a problem that it ends up. In fact, even if the passenger is away from the seat, when the occupant travels backward, there is a case where the waist is lifted from the driver's seat in order to see the back, and in such a case, steering force and braking force can be obtained. What can't be done is a problem.

  The present invention has been made in view of the above circumstances, and relates to a hydraulic system for an industrial vehicle including a hydraulic device driven by pressure oil supplied from a pump, and when a passenger is not seated in a driver's seat, cargo handling is performed. An industry capable of limiting the occurrence of an inadvertent operating state of the device with a simple configuration and suppressing the unnecessary operation of the hydraulic device other than the cargo handling device. An object is to provide a hydraulic system for a vehicle.

Means and effects for solving the problems

The present invention relates to a hydraulic system for an industrial vehicle including a hydraulic device driven by pressure oil supplied from a pump.
The industrial vehicle hydraulic system according to the present invention has the following features in order to achieve the above object. In other words, the present invention includes the following features alone or in combination as appropriate.

  In order to achieve the above object, a first feature of the hydraulic system for an industrial vehicle according to the present invention is a cargo handling device that is a hydraulic device that is driven by pressure oil supplied from the pump to perform a cargo handling operation, and the pump. A hydraulic device driven by the supplied pressure oil and having at least one of a steering device for performing a steering operation in the industrial vehicle and a braking device for performing a braking operation, and an occupant driving the industrial vehicle Occupant detection means for detecting whether or not the driver is seated in the driver's seat, and when the occupant detection means detects that the occupant is not seated in the driver's seat, from the pump to the cargo handling device And a supply amount limiting means for limiting the supply amount of the pressure oil.

  According to this configuration, when the occupant is away from the driver's seat, the amount of pressure oil supplied from the pump to the cargo handling device is limited. For this reason, since the operation capability of the cargo handling device is limited in the absence state, the cargo handling device is restricted from performing an inadvertent operation contrary to the driver's will. Further, it is only necessary to limit the amount of pressure oil supplied to the cargo handling device, and it is not necessary to separately provide a mechanism for shutting off the hydraulic circuit, and it is easy to limit the inadvertent operation of the cargo handling device in the away state. It can be realized with a simple mechanism. In addition, since only the amount of pressure oil supplied to the cargo handling device is limited, the hydraulic fluid of other functions can be appropriately supplied to the hydraulic device of other functions, so The operating ability can be secured. Therefore, when the passenger is not seated in the driver's seat, it is possible to limit the occurrence of an inadvertent operation state of the cargo handling device with a simple configuration, and to operate the hydraulic device other than the cargo handling device. Unnecessary restriction can be suppressed.

  A second feature of the industrial vehicle hydraulic system according to the present invention is that the supply amount limiting means is capable of supplying pressure oil at a flow rate capable of being operated by the hydraulic device having the other function. The supply amount of the pressure oil to the cargo handling device is limited by limiting the discharge amount of the pressure oil.

  According to this configuration, since the discharge amount of the pressure oil from the pump is limited to the extent that the operation by the hydraulic device of another function is possible, the operation of the hydraulic device of the other function is unnecessarily restricted in the away state. Can be prevented. Moreover, the supply amount of the pressure oil to the cargo handling device can be limited with a simple configuration in which the discharge amount of the pump is limited and limited.

  According to a third aspect of the hydraulic system for an industrial vehicle according to the present invention, the hydraulic device having the other function includes the braking device, and the supply amount limiting means has a flow rate at which a braking operation can be performed by the braking device. The supply amount of the pressure oil to the cargo handling device is limited by limiting the discharge amount of the pressure oil from the pump within a range in which the pressure oil can be supplied.

  According to this configuration, since the discharge amount of the pressure oil from the pump is limited within a range in which the braking operation can be performed, the supply amount of the pressure oil to the cargo handling device with a simple configuration that restricts the discharge amount of the pump in the away state. And the braking operation can be prevented from being unnecessarily restricted. And when it is necessary to perform a braking operation urgently, a quicker braking operation can be performed even if the user is away from the seat.

  According to a fourth aspect of the industrial vehicle hydraulic system of the present invention, the hydraulic system of the other function further includes a detecting unit that detects an operation amount of the hydraulic device having the other function, and the supply amount limiting unit is a detection result of the detecting unit. To the cargo handling device by restricting the discharge amount of the pressure oil from the pump within a range in which the pressure oil having a flow rate corresponding to the operation amount of the hydraulic device having the other function can be supplied to the hydraulic device having the other function. The amount of pressure oil supplied is limited.

  According to this configuration, the discharge amount of the pressure oil from the pump is limited within a range in which the operation according to the operation amount of the hydraulic device having another function can be performed based on the detection result by the detection unit. For this reason, the supply amount of pressure oil to the cargo handling device is limited with a simple configuration of reducing the discharge amount of the pump in the away state, and the operation according to the operation amount of the hydraulic device of other functions is unnecessarily limited. Can be prevented.

  According to a fifth feature of the hydraulic system for an industrial vehicle according to the present invention, the discharge amount of the pressure oil from the pump is defined as a first discharge amount and a second discharge amount having a smaller flow rate than the first discharge amount. The discharge amount setting means can be set to two types, and is set to the second discharge amount when the absence state is detected by the occupant detection means, and the supply amount setting means includes the discharge amount The operation of the pump is controlled so that the pressure amount of the pressure oil set by the setting means is discharged, and the cargo handling device is set from the pump by setting the second discharge amount by the discharge amount setting means. The supply amount of pressure oil to the is limited.

  According to this configuration, when the pump discharge amount is set to the second discharge amount with a small flow rate in the away state, the pressure oil to the cargo handling device is configured with a simple configuration in which the pump discharge amount is set to the small flow rate. In addition to restricting the supply amount, it is possible to suppress unnecessary restriction of the operation of the hydraulic device having other functions. Moreover, since there are only two types of pump discharge amount settings, the pump discharge amount can be easily controlled by the supply amount setting means.

  A sixth feature of the industrial vehicle hydraulic system according to the present invention is that the supply amount limiting means reduces the rotational speed of the pump to limit the discharge amount of the pump, thereby reducing the pressure oil to the cargo handling device. It is to limit the supply amount.

  According to this configuration, the amount of pressure oil supplied to the cargo handling device is limited with a simple configuration in which the pump rotation speed is reduced by reducing the pump rotation speed in the absence state, thereby reducing the pump rotation speed. It is possible to prevent the operation of the functional hydraulic device from being unnecessarily restricted. Further, since only the rotation speed of the pump is changed, the supply amount of the pressure oil by the supply amount limiting means can be easily controlled.

  A seventh feature of the industrial vehicle hydraulic system according to the present invention is that, even when the cargo handling device is operated, the supply of pressure oil to the cargo handling device and the handling of the cargo handling device are prohibited so as to prohibit the cargo handling operation based on the operation. Cargo handling prohibiting means that operates to regulate at least one of the discharge of pressure oil; cargo handling prohibiting control means that operates the cargo handling prohibiting means when the unoccupied state is detected by the occupant detection means; Is further provided.

  According to this configuration, in the absence state, even if an operation is performed, the operation of the cargo handling device is reliably restricted. Therefore, in addition to restricting the occurrence of an inadvertent operation state of the cargo handling device in the absence state and suppressing the unnecessary operation of the hydraulic device of other functions, the operation of the cargo handling device is more reliably prohibited. be able to.

  The eighth feature of the hydraulic system for an industrial vehicle according to the present invention is that the cargo handling device includes a lift device that has a single-acting lift cylinder and moves the cargo up and down, and the cargo handling prohibiting means includes the lift A descent lock valve mechanism provided to be connected to an oil chamber of the cylinder and capable of regulating the movement of the lift cylinder in the descent direction, wherein the cargo handling prohibition control means detects the absence state by the occupant detection means When the lowering lock valve mechanism is operated, the lowering operation of the lift cylinder is restricted.

  According to this configuration, even when the lift device is operated in the absence state, the operation in the descending direction of the lift cylinder is reliably restricted. The downward movement of the single-acting lift cylinder is performed according to gravity by discharging the pressure oil from the oil chamber of the lift cylinder. Therefore, even if the pump operation is limited, the lowering speed, which is the cargo handling speed, is reduced. It cannot be restricted. Therefore, by providing the lowering lock valve as the cargo handling prohibiting means, the lowering operation of the lift cylinder can be reliably regulated in the away state.

  According to a ninth feature of the industrial vehicle hydraulic system according to the present invention, the cargo handling device includes a tilt device that includes a tilt cylinder and performs a tilting operation of a lift device that performs the lifting and lowering operation of the load. As described above, a forward tilt lock valve mechanism provided to be connected to the oil chamber of the tilt cylinder and capable of regulating the forward tilt operation by the tilt cylinder and the rear tilt lock valve capable of regulating the rear tilt operation by the tilt cylinder And the cargo handling prohibition control means activates the forward tilt lock valve mechanism or the rear tilt lock valve mechanism when the occupant detection means detects the absence state. This restricts the operation of the tilt cylinder.

  According to this configuration, even when the tilt device is operated in the away state, the forward tilting operation or the backward tilting operation of the tilt cylinder can be reliably restricted.

  Hereinafter, the best mode for carrying out the present invention will be described with reference to the drawings.

  First, an industrial vehicle provided with an industrial vehicle hydraulic system according to an embodiment of the present invention will be described. FIG. 1 is a side view of a forklift 10 that is an example of an industrial vehicle. The forklift 10 shown in FIG. 1 is configured as, for example, a front wheel drive / rear wheel steering four-wheel vehicle. A forklift 10 is provided with a lift device 11 that performs a lifting / lowering operation of the load and a tilt device 12 that performs a forward / backward tilting operation of the lift device 11.

  As shown in FIG. 1, the lift device 11 includes a pair of left and right outer masts 13, an inner mast 14 disposed so as to be movable up and down with respect to the outer mast 13, a sprocket and a chain (not shown). A fork 15 suspended from the inner mast 14 so as to be lifted and loaded with a load and a single-acting lift cylinder 16 for driving the inner mast 14 up and down relative to the outer mast 13 are provided.

  The tilt device 12 includes a tilt cylinder 17 and a rod 18. The tilt cylinder 17 is supported such that one end thereof is rotatable with respect to the vehicle body frame 19 of the forklift 10. The rod 18 is disposed so as to be able to move back and forth with respect to the tilt cylinder 17, and a tip end side thereof is attached so as to be rotatable with respect to the outer mast 13. The outer mast 13 of the lift device 11 is connected to the vehicle body frame 19 via the tilt device 12 so as to be tiltable. That is, the lift device 11 performs the forward tilting operation by performing the extending operation in the direction in which the rod 18 protrudes from the tilt cylinder 17. On the other hand, when the rod 18 is retracted in the direction in which the rod 18 is accommodated in the tilt cylinder 17, the lift device 11 performs the backward tilting operation.

  A driver's cab 20 is provided in the upper part of the vehicle body frame 19 of the forklift 10, and a driver's seat (driver's seat) 21 on which a passenger who drives the forklift 10 is seated is disposed in the driver's cab 20. Further, a steering wheel 22 for a steering operation in the forklift 10, an accelerator pedal (not shown) for an acceleration operation, a brake pedal 23 for a braking operation, and the like are provided at a front portion in the cab 20. .

  Hereinafter, a hydraulic system for an industrial vehicle according to an embodiment of the present invention that includes a hydraulic device that is provided on the forklift 10 and that is driven by pressure oil from a pump will be described in the first to third embodiments. To do.

(First embodiment)
FIG. 2 is a hydraulic system diagram showing a hydraulic circuit 30 provided in the hydraulic system 1 (hereinafter simply referred to as “hydraulic system 1”) for an industrial vehicle according to the first embodiment of the present invention. An arrow (an arrow other than an arrow indicating the operation direction of the steering wheel 22) shown in the drawing indicates a direction in which hydraulic oil (pressure oil) flows.

  As shown in FIG. 2, the hydraulic circuit 30 of the hydraulic system 1 includes a tank 31, a pump 32, the above-described lift device 11 and tilt device 12, a power steering device 33, a brake assist device 34, and the like. The hydraulic oil is accumulated in the tank 31, and the hydraulic oil sucked from the tank 31 through the suction filter 35 is boosted by a pump 32 driven by a motor 36. The lift device 11, the tilt device 12, the power steering device 33, and the brake assist device 34 are driven by the pressure oil supplied from the pump 32.

  The lift device 11 and the tilt device 12 are provided as a cargo handling device that is a hydraulic device that performs a cargo handling operation. Then, after the pressure oil from the pump 32 passes through the flow divider 37 which is a flow dividing mechanism, the pressure oil is supplied to the lift cylinder 16 and the tilt cylinder 17 via the control valve 38, and the pressure oil discharged from the lift cylinder 16 and the tilt cylinder 17 is supplied. After passing through the control valve 38, the return filter 45 returns to the tank 31. That is, the control valve 38 controls the supply and discharge of pressure oil to and from the lift cylinder 16 and the tilt cylinder 17.

  The power steering device 33 is provided as a steering device that performs a steering operation in the forklift 10, and the brake assist device 34 is provided as a braking device that performs a braking operation of the forklift 10. The power steering device 33 and the brake assist device 34 constitute a hydraulic device having a function other than the cargo handling device. The power steering device 33 includes a steering valve 39, a solenoid valve unit 40, and a power steering cylinder 41. Pressure oil divided from the flow divider 37 is supplied via a brake switching valve 42 and a brake valve 43. A rear wheel (see FIG. 1), which is a steered wheel, is steered according to the amount of operation of the steering 22. The brake assist device 34 is supplied with pressure oil via the flow divider 37, the brake switching valve 42, and the brake valve 43, and can exert a braking force according to the operation amount (depression amount) of the brake pedal 23. It is like that. Note that pressure oil can be supplied to the parking brake 44 via the brake switching valve 42.

  FIG. 3 shows a block diagram of the hydraulic system 1. As described above, the hydraulic system 1 includes the pump 32, the motor 36 that is a pump driving means, the lift device 11 and the tilt device 12 that are cargo handling devices, and the power steering device (steering device) that is a hydraulic device having other functions. 33 and a brake assist device (braking device) 34. As shown in FIG. 3, the hydraulic system 1 further includes various sensors (46, 47, 48, 49) that detect operations of the cargo handling devices (11, 12) and the hydraulic devices (33, 34) having other functions. ), A controller 50, and an occupant detection sensor 51.

  The steering angle sensor 46 constitutes detection means for detecting an operation angle of the steering wheel 22 (see FIG. 2) that is actually operated (that is, an operation amount by which the power steering device 33 is operated). Further, the brake pedal sensor 47 constitutes a detecting means for detecting the amount of depression of the brake pedal 23 by the occupant of the forklift 10 (that is, the operation amount when the brake assist device 34 is operated). The steering angle sensor 46 and the brake pedal sensor 47 constitute detection means for detecting an operation amount when the hydraulic device having another function is operated. Each of these sensors (46, 47) is connected to the controller 50, and the detection signal is input to the controller 50.

  The lift lever sensor 48 constitutes a lift operation detection unit that detects an operation state of a lift lever that is a lift operation unit that operates the lift device 11. The tilt lever sensor 49 constitutes a tilt operation detecting means for detecting the operation state of the tilt lever, which is a tilt operating means for operating the tilt device 12. Each of these sensors (48, 49) is connected to the controller 50, and the detection signal is input to the controller 50.

  The occupant detection sensor 51 constitutes occupant detection means for detecting whether or not the occupant driving the forklift 10 is seated on the operation seat 21 (see FIG. 1). The occupant detection sensor 51 is provided on the driving seat 21 and is configured as a switch that opens and closes depending on the weight of the occupant when the occupant sits on the driving seat 21. When the occupant is seated on the driver's seat 21, the switch (sensor 51) is closed to detect the seated state, and when the occupant leaves the seat, the switch (sensor 51) is opened to leave the seat. Is supposed to be detected.

  The controller 50 includes a CPU (Central Processing Unit) and a memory (ROM (Read Only Memory), RAM (Random Access Memory)) and the like (not shown). The memory stores various software including a program for controlling operation of the motor 36 based on signals input from the sensors (46 to 49, 51). By combining these hardware and software, a supply amount limiting unit (supply amount limiting means) 52 and the like are built in the controller 50.

  When the occupant detection sensor 51 detects that the occupant is not seated in the driver's seat, the supply amount limiting unit 52 controls the rotation of the motor 36 to reduce the rotation speed of the pump 32 and thereby reduce the pump 32. The discharge amount of the pressure oil from is restricted. As a result, the amount of pressure oil supplied from the pump 32 to the lift device 11 and the tilt device 12 is limited. At this time, the supply amount limiting unit 52 supplies a flow rate of pressure oil that can be braked by the brake assist device 34 and a flow rate of hydraulic oil that can be steered by the power steering device 33. By limiting the discharge amount from the pump 32 within a possible range, the supply amount of pressure oil to the lift device 11 and the tilt device 12 is limited. In addition, the supply amount limiting unit 52 supplies pressure oil having a flow rate according to the operation amounts of the power steering device 33 and the brake assist device 34 based on the detection results of the steering angle sensor 46 and the brake pedal sensor 47 for these other functions. The supply amount of the pressure oil to the lift device 11 and the tilt device 12 is limited by limiting the discharge amount of the pressure oil from the pump 32 within a range that can be supplied to the hydraulic device (33, 34).

  Next, the operation of the hydraulic system 1 described above will be described. FIG. 4 is a diagram for explaining the operation of the hydraulic system 1 and shows a change in the rotational speed of the pump 32 when a cargo handling operation by the cargo handling device or an operation by a hydraulic device having another function is performed. is there.

  As shown in FIG. 4, first, when the occupant sits on the operation seat 21 of the forklift 10 and operates the key switch to turn it on, the motor 36 is activated based on a command from the controller 50, and a predetermined low speed rotation speed is obtained. The rotational speed of the pump 32 is controlled to rotate at a. When the cargo handling device (11, 12) or the hydraulic device (33, 34) having another function is not operated, the rotational speed of the pump 32 is maintained at the low rotational speed a.

  When the cargo handling operation is started in a state where the rotational speed of the pump 32 is maintained at the low rotational speed a, the motor 36 is controlled by the controller 50 so that the rotational speed of the pump 32 increases according to the operation amount of the cargo handling operation. It is controlled and the load necessary for the cargo handling operation is secured. At this time, the occupant is seated on the driving seat 21, and the occupant detection sensor 51 detects the seated state. For this reason, the discharge amount of the pump 32 is not limited by the supply amount limiting unit 52 of the controller 50, and the rotation speed of the pump 32 is increased or decreased in accordance with the cargo handling operation within the range up to the rated maximum rotation speed of the pump 32. Control will be performed.

  As described above, while the occupant is seated on the driver's seat 21 and the seating state is detected by the occupant detection sensor 51, the cargo handling operation is not limited by the control of the supply amount limiting unit 52. However, when the occupant leaves the driver's seat 21, the occupant detection sensor 51 detects the absence state, and the supply amount of the pressure oil to the cargo handling device (11, 12) is controlled by the control of the supply amount limiting unit 52 based on this. Will be limited. FIG. 4 illustrates a case where the occupant leaves the seat during the cargo handling operation and the occupant detection sensor 51 detects the away state. As described above, when the absence state is detected in the middle of the cargo handling operation, the rotation speed of the pump 32 is controlled to be lowered to the low speed rotation speed a based on the command from the controller 50. And while the absence state is detected, the rotational speed of the pump 32 is maintained at the low rotational speed a even if only the cargo handling operation is performed by the occupant.

  However, if the other device hydraulic device (33, 34) is operated in the state where the away state is detected and maintained at the low rotational speed a as described above, as shown in FIG. Is controlled within a rotation speed range (within a range up to the rotation speed b) in which the flow rate of pressure oil that can be operated by the hydraulic devices (33, 34) having other functions is supplied. FIG. 4 illustrates the case where the brake pedal 23 is operated. In this case, the supply of pressure oil to the cargo handling devices (11, 12) is limited and based on the detection result of the brake pedal sensor 47. Thus, the rotational speed of the pump 32 is controlled so that the braking operation according to the operation amount of the brake pedal 23 is ensured. Similarly, when the steering wheel 22 is operated, a steering operation corresponding to the operation amount of the steering wheel 22 is ensured based on the detection result of the steering angle sensor 46. When the occupant sits on the driving seat 21 again and the occupant detection sensor 51 detects the seating state, the restriction on the supply of pressure oil from the pump 32 to the cargo handling device (11, 12) is released. The cargo handling operation corresponding to the cargo handling operation is enabled.

  As described above, according to the hydraulic system 1, when the occupant is not seated on the operation seat 21, the supply amount of the pressure oil from the pump 32 to the cargo handling device (11, 12) is limited. become. For this reason, since the operation capability of the cargo handling device (11, 12) is limited in the unattended state, the cargo handling device (11, 12) is restricted from performing an inadvertent operation contrary to the intention of the driver. The And it is only necessary to restrict the amount of pressure oil supplied to the cargo handling device (11, 12), and it is not necessary to provide a separate mechanism for shutting off the hydraulic circuit, and the cargo handling device (11, 12) in the unseated state. Limiting inadvertent operation can be realized with a simple mechanism. In addition, since only the amount of pressure oil supplied to the cargo handling device (11, 12) is limited, by appropriately supplying the required amount of pressure oil to the hydraulic device (33, 34) of other functions, The operation capability of the hydraulic device (33, 34) having other functions can be ensured as required. Therefore, when a passenger is not seated in the driver's seat, an inadvertent operation state of the cargo handling device (11, 12) can be restricted with a simple configuration, and the hydraulic device (33 with other functions) can be restricted. , 34) can be prevented from being unnecessarily limited.

  Further, according to the hydraulic system 1, since the discharge amount of the pressure oil from the pump 32 is limited to the extent that the operation by the hydraulic device (33, 34) with another function is possible, the hydraulic device with another function ( 33, 34) can be prevented from being unnecessarily restricted. Moreover, the supply amount of the pressure oil to the cargo handling devices (11, 12) can be limited with a simple configuration in which the discharge amount of the pump 32 is limited and limited.

  Further, according to the hydraulic system 1, since the discharge amount of the pressure oil from the pump 32 is limited within a range where the braking operation is possible, the cargo handling apparatus (11 , 12) and the brake operation can be prevented from being unnecessarily restricted. And when it is necessary to perform a braking operation urgently, a quicker braking operation can be performed even if the user is away from the seat.

  Further, according to the hydraulic system 1, the pressure oil from the pump 32 is within a range in which the operation according to the operation amount of the hydraulic device (33, 34) of another function is possible based on the detection result by the detection means (46, 47). Discharge amount is limited. For this reason, the supply amount of the pressure oil to the cargo handling device (11, 12) is limited by a simple configuration in which the discharge amount of the pump 32 is reduced in the away state, and the operation amount of the hydraulic device (33, 34) having other functions. It is possible to prevent the operation according to the condition from being unnecessarily limited.

  Further, according to the hydraulic system 1, the pressure applied to the cargo handling device (11, 12) can be reduced with a simple configuration in which the pump rotational speed is reduced by reducing the rotational speed of the pump 32 and limiting the discharge amount in the absence state. It is possible to restrict the amount of oil supplied and prevent the hydraulic devices (33, 34) having other functions from being unnecessarily restricted. Further, since only the rotation speed of the pump 32 is changed, the supply amount of the pressure oil by the supply amount restriction unit 52 can be easily controlled.

  The first embodiment of the present invention has been described above. However, the present invention is not limited to the above-described embodiment, and various modifications are possible as long as they are described in the claims. For example, the following modifications can be made.

(1) In the first embodiment, the case where the lift device and the tilt device are provided as the cargo handling device has been described as an example. However, this need not be the case. For example, only one of the lift device and the tilt device may be provided, or a cargo handling device other than the lift device and the tilt device may be provided.

(2) In the first embodiment, the case where both the braking device and the steering device are provided as hydraulic devices having other functions has been described as an example. However, this need not be the case, and either one of them may be provided. It may be provided with only.

(3) In the first embodiment, the occupant detection sensor configured as a switch provided on the driving seat as the occupant detection means has been described as an example. However, this need not be the case. For example, those using a floor switch provided on the floor of the cab, those using a seat belt switch that works in conjunction with the attachment / detachment of the seat belt, those using an infrared sensor, those using a switch provided on the steering wheel, The present invention can be implemented in various forms such as those using a wireless card (such as a smart ID card).

(4) In the first embodiment, the case where the discharge amount of the pressure oil from the pump is limited by controlling the rotation speed of the pump as a form for limiting the supply amount of the pressure oil to the cargo handling device has been described as an example. However, this is not necessarily the case. For example, the variable displacement pump may be limited by switching the capacity, or may be limited by providing a bypass valve or a flow restriction valve. Moreover, you may restrict | limit the supply amount of the pressure oil to a cargo handling apparatus by stopping a pump. When the pump is stopped, pressure accumulating means such as an accumulator can be provided so that pressure oil can be supplied to a hydraulic device having another function.

(5) In the first embodiment, the case where the pump driving means is a motor has been described as an example. However, this need not be the case. For example, the pump may be driven by an engine. In this case, a variable speed / variable torque transmission device may be provided to limit the driving force transmission to the pump.

(Second Embodiment)
Next, a second embodiment of the present invention will be described. FIG. 5 is a block diagram of an industrial vehicle hydraulic system 2 (hereinafter simply referred to as “hydraulic system 2”) according to the second embodiment. Similar to the hydraulic system 1 of the first embodiment, the hydraulic system 2 includes a pump 32, a motor 36, a power steering device 33, a brake assist device 34, a lift device 11, a tilt device 12, a steering angle sensor 46, and a brake pedal sensor 47. , A lift lever sensor 48, a tilt lever sensor 49, an occupant detection sensor 51, and the like. However, the hydraulic system 2 is partially different from the controller 50 of the first embodiment in the configuration of the controller 50a.

  The controller 50a of the hydraulic system 2 is configured by a supply amount restriction unit 52a and a discharge amount setting unit (discharge amount setting means) 53 being built inside. The discharge amount setting unit 53 can set the discharge amount of the pressure oil from the pump 32 to two types of a first discharge amount and a second discharge amount having a smaller flow rate than the first discharge amount. . The discharge amount setting unit 53 sets the second discharge amount when the occupant detection sensor 51 detects the absence state. The first discharge amount with a large flow rate is set to a flow rate at which the cargo handling device (11, 12) and the hydraulic device (33, 34) with other functions can operate. On the other hand, the second discharge amount with a small flow rate is set to a flow rate at which the operation of the hydraulic device (33, 34) of another function is limited although the operation of the cargo handling device (11, 12) is limited.

  Further, the supply amount limiting unit 52a of the controller 50a controls the operation of the pump 32 so that the discharge amount of pressure oil set by the discharge amount setting unit 53 is discharged. And by setting to the 2nd discharge amount by the discharge amount setting part 53, the supply amount of the pressure oil from the pump 32 to the cargo handling apparatus (11, 12) is restrict | limited.

  FIG. 6 is a view for explaining the operation of the hydraulic system 2 and corresponds to FIG. 4 of the first embodiment. As shown in FIG. 6, first, when an occupant sits on the operation seat 21 of the forklift 10 and turns on the key switch, the motor 36 is started based on a command from the controller 50a. Then, the rotational speed of the pump 32 is controlled so as to rotate at the second rotational speed c that is the pump rotational speed corresponding to the second discharge amount that is the setting of the small flow rate. In a state where the cargo handling device (11, 12) or the hydraulic device (33, 34) of another function is not operated, the rotational speed of the pump 32 is maintained at the second rotational speed c.

  When the cargo handling operation is started in a state where the rotation speed of the pump 32 is maintained at the second rotation speed c, the first rotation that is the pump rotation speed corresponding to the first discharge amount that is set to a large flow rate. The rotation of the pump 32 is controlled to rotate at the speed d. Thereby, the load required for the cargo handling operation is ensured. At this time, the occupant is seated on the driving seat 21, and the occupant detection sensor 51 detects the seated state. While the cargo handling operation is performed in the seated state, the rotational speed of the pump 32 is maintained at the first rotational speed d.

  In the seated state, the cargo handling operation is not restricted by the control of the supply amount restriction unit 52a. However, when the occupant leaves the driver's seat 21, the occupant detection sensor 51 detects the absence state, and the supply of the pressure oil to the cargo handling devices (11, 12) is restricted by the control of the supply amount restriction unit 52a based on this. Will be. FIG. 6 illustrates a case where the occupant leaves the seat during the cargo handling operation and the occupant detection sensor 51 detects the away state. As described above, when the absence state is detected in the middle of the cargo handling operation, the rotational speed of the pump 32 is controlled so as to decrease to the second rotational speed c based on the command from the controller 50a. And while the absence state is detected, the rotational speed of the pump 32 is maintained at the second rotational speed c even if the cargo handling operation is performed by the occupant. Other functions that restrict the operation of the cargo handling device (11, 12) in the away state by the pump 32 rotating at the second rotational speed c and the second discharge amount of pressurized oil being supplied. The supply of pressure oil at a flow rate capable of operating the hydraulic devices (33, 34) is ensured.

  As described above, according to the hydraulic system 2, the pump discharge amount is set to the second discharge amount with a small flow rate in the away state, so that the pump discharge amount is set to the small flow rate. Thus, it is possible to restrict the amount of pressure oil supplied to the cargo handling device (11, 12) and to suppress the unnecessary operation of the hydraulic devices (33, 34) having other functions. In addition, since there are only two types of pump discharge amount settings, the pump discharge amount can be easily controlled by the supply amount setting unit 53.

  The second embodiment of the present invention has been described above, but the present invention is not limited to the above-described embodiment, and various modifications are possible as long as they are described in the claims.

(Third embodiment)
Next, a third embodiment of the present invention will be described. FIG. 7 is a block diagram of a hydraulic system 3 (hereinafter simply referred to as “hydraulic system 3”) for an industrial vehicle according to the third embodiment. Similar to the hydraulic system 1 of the first embodiment, the hydraulic system 3 includes a pump 32, a motor 36, a power steering device 33, a brake assist device 34, a lift device 11, a tilt device 12, a steering angle sensor 46, and a brake pedal sensor 47. , A lift lever sensor 48, a tilt lever sensor 49, an occupant detection sensor 51, and the like. However, the hydraulic system 3 is different in part in the configuration of the controller 50b and also in that it includes a lift lock valve 55 and a tilt lock valve 56 as cargo handling prohibiting means.

  The controller 50b of the hydraulic system 3 is configured by a supply amount restriction unit 52b and a cargo handling prohibition control unit 54 being built inside. The supply amount restriction unit 52b is configured in the same manner as the supply amount restriction unit 52 of the controller 50 of the first embodiment. The cargo handling prohibition control unit 54 controls the lift lock valve 55 and the tilt lock valve 56 to be prohibited by operating the lift lock valve 55 and the tilt lock valve 56 as will be described later when the occupant detection sensor 51 detects the absence state.

  The lift lock valve 55 and the tilt lock valve 56 as the cargo handling prohibiting means are pressurized oil to the cargo handling device (11, 12) so as to prohibit the cargo handling operation based on the operation even when the cargo handling device (11, 12) is operated. It is comprised as a means which act | operates so that discharge of the pressure oil from supply and cargo handling apparatus (11, 12) may be regulated.

  FIG. 8 illustrates a part of the hydraulic circuit in the hydraulic system 3 and is a hydraulic circuit diagram for explaining the cargo handling prohibiting means. As shown in FIG. 8, the hydraulic system 3 has a control valve 38 as in the first embodiment, and the pressure oil from the pump 32 to the cargo handling device (11, 12) via the control valve 38. Is controlled. The control valve 38 is provided with an attachment direction switching valve 57, a tilt direction switching valve 58, and a lift direction switching valve 59. The tilt direction switching valve 58 is controlled to be supplied from the neutral position 58b to the switching position 58a or the switching position 58b, thereby controlling the supply and discharge of the pressure oil to the tilt cylinder 17 and moving the tilt device 12 back and forth. Can be made to. The lift direction switching valve 59 is switched from the neutral position 59a to the switching position 59b or the switching position 59c, thereby controlling the supply and discharge of the pressure oil to the lift cylinder 16 and ascending / descending the lift device 11. It can be operated.

  The tilt lock valve 56 as the cargo handling prohibiting means is provided so as to be connected to the oil chamber of the tilt cylinder 17 and is configured as an electromagnetic valve that can be switched between the communication position 56a and the shut-off position 56b. The tilt lock valve 56 does not restrict the flow of pressure oil between the tilt direction switching valve 58 and the tilt cylinder 17 in the state of the communication position 56a. When the seating state is detected by the occupant detection sensor 51, the tilt lock valve 56 is energized and energized based on a command from the controller 50b to be held at the communication position 56a. Yes. In this state, when the occupant detection sensor 51 detects the absence state, the cargo handling prohibition control unit 54 of the controller 50b operates the tilt lock valve 56. In other words, when the absence state is detected, the tilt lock valve 56 is deenergized and de-energized based on a command from the cargo handling prohibition control unit 54 to be switched to the blocking position 56b. Yes. As described above, the tilt lock valve 56 is operated and switched to the cutoff position 56b, whereby the operation of the tilt cylinder 16 is restricted. Therefore, the tilt lock valve 56 functions as a forward tilt lock valve mechanism that can regulate the forward tilt operation by the tilt cylinder 17 and also functions as a rear tilt lock valve mechanism that can regulate the rear tilt operation by the tilt cylinder 17. Can also be fulfilled.

  Further, the lift lock valve 55 as the cargo handling prohibiting means is provided so as to be connected to the oil chamber of the lift cylinder 16, and is configured as an electromagnetic valve that can be switched between the communication position 55a and the blocking position 55b. Yes. The lift lock valve 55 does not restrict the flow of pressure oil between the lift direction switching valve 59 and the lift cylinder 16 in the state of the communication position 55a. When the seating state is detected by the occupant detection sensor 51, the lift lock valve 55 is energized and excited based on a command from the controller 50b, so that the lift lock valve 55 is held at the communication position 55a. Yes. In this state, when the occupant detection sensor 51 detects the absence state, the cargo handling prohibition control unit 54 of the controller 50b operates the lift lock valve 55. That is, when the absence state is detected, the lift lock valve 55 is deenergized and de-energized based on a command from the cargo handling prohibition control unit 54 to be switched to the blocking position 55b. Yes. Thus, the lift lock valve 55 is operated and switched to the blocking position 55b, whereby the operation of the lift cylinder 16 is restricted. Accordingly, the lift lock valve 55 functions as a descending lock valve mechanism that can regulate the downward movement of the lift cylinder 16 and functions as an upward lock valve mechanism that can regulate the upward movement of the lift cylinder 16. Can also be fulfilled.

  As described above, according to the hydraulic system 3, since the cargo handling prohibition control unit 54 and the cargo handling prohibition means (55, 56) are provided, the operation of the direction switching valves (58, 59) can be performed in the away state. Even if it is performed, the operation of the cargo handling device (11, 12) is surely restricted. Therefore, in addition to being able to suppress unnecessarily restricting the operation of the hydraulic devices (33, 34) of other functions by limiting the occurrence of an inadvertent operation state of the cargo handling device (11, 12) in the absence state, Furthermore, the operation of the cargo handling device (11, 12) can be prohibited with certainty.

  Further, according to the hydraulic system 3, since the lift lock valve 55 that functions as a lowering lock valve mechanism is provided, even if the lift device 11 is operated in the away state, the lowering direction of the lift cylinder 16 is achieved. The operation of is surely regulated. Since the movement of the lift cylinder 16 in the descending direction is performed according to gravity by discharging the pressure oil from the oil chamber of the lift cylinder 16, even if the operation of the pump 32 is limited, the descending speed that is the cargo handling speed is limited. Can not do it. For this reason, by providing the lowering lock valve as the cargo handling prohibiting means, the lowering operation of the lift cylinder 16 can be reliably regulated in the away state. Further, according to the hydraulic system 3, since the tilt lock valve 56 is provided, the forward tilting operation and the backward tilting operation of the tilt cylinder 17 are surely restricted even when the tilt device 12 is operated in the away state. can do.

  The third embodiment of the present invention has been described above, but the present invention is not limited to the above-described embodiment, and various modifications are possible as long as they are described in the claims. For example, the following modifications can be made.

(1) In the third embodiment, the case where both the lift lock valve and the tilt lock valve are provided has been described as an example. However, only one of them may be provided.

(2) In the third embodiment, the lift lock valve that can regulate both the upward movement and the downward movement of the lift cylinder has been described as an example, but either the upward or downward movement is described. It may be configured to regulate only the above. Further, the tilt lock valve that can regulate both the forward tilting operation and the backward tilting operation of the tilt cylinder has been described as an example, but it is configured to restrict only one of the forward tilting operation and the backward tilting operation. It may be. In the case of providing a lock valve mechanism that restricts only one operation, for example, a circuit in which a check valve and an electromagnetic valve are arranged in parallel can be used.

It is a side view which shows the forklift which is an illustration of an industrial vehicle. 1 is a hydraulic system diagram showing a hydraulic circuit provided in a hydraulic system for an industrial vehicle according to a first embodiment of the present invention. 1 is a block diagram illustrating a hydraulic system for an industrial vehicle according to a first embodiment of the present invention. It is a figure for demonstrating the action | operation of the hydraulic system shown in FIG. It is a block diagram which shows the hydraulic system of the industrial vehicle which concerns on 2nd Embodiment of this invention. It is a figure for demonstrating the action | operation of the hydraulic system shown in FIG. It is a block diagram which shows the hydraulic system of the industrial vehicle which concerns on 3rd Embodiment of this invention. FIG. 8 is a hydraulic circuit diagram illustrating a part of a hydraulic circuit in the hydraulic system illustrated in FIG. 7.

Explanation of symbols

1 Industrial Vehicle Hydraulic System 10 Forklift (Industrial Vehicle)
11 Lifting device (handling device)
12 Tilt device (handling device)
21 Driver's seat (driver's seat)
32 Pump 33 Power steering device (steering device, hydraulic device with other functions)
34 Brake assist device (braking device, hydraulic device with other functions)
50 controller 51 occupant detection sensor (occupant detection means)
52 Supply amount restriction unit (Supply amount restriction means)

Claims (9)

An industrial vehicle hydraulic system including a hydraulic device driven by pressure oil supplied from a pump,
A cargo handling device which is a hydraulic device driven by pressure oil supplied from the pump to perform a cargo handling operation;
A hydraulic device having other functions including at least one of a steering device that performs a steering operation in the industrial vehicle and a braking device that performs a braking operation, driven by pressure oil supplied from the pump;
Occupant detection means for detecting whether an occupant driving the industrial vehicle is seated in the driver's seat;
A supply amount restriction means for restricting the supply amount of pressure oil from the pump to the cargo handling device when the occupant detection means detects that the occupant is not seated in the driver's seat;
An industrial vehicle hydraulic system characterized by comprising:   The supply amount restricting means restricts the discharge amount of the pressure oil from the pump within a range in which the pressure oil can be supplied at a flow rate capable of being operated by the hydraulic device having the other function. 2. The hydraulic system for an industrial vehicle according to claim 1, wherein the supply amount of oil is limited. The other-function hydraulic device includes the braking device,
The supply amount restricting means restricts the discharge amount of the pressure oil from the pump within a range in which the pressure oil that can be braked by the braking device can be supplied, thereby reducing the pressure oil to the cargo handling device. The hydraulic system for an industrial vehicle according to claim 1 or 2, wherein a supply amount is limited. It further comprises detection means for detecting an operation amount by which the hydraulic device having the other function is operated,
The supply amount limiting means is configured to reduce the pressure from the pump within a range in which pressure oil having a flow rate corresponding to the operation amount of the other function hydraulic device can be supplied to the other function hydraulic device based on the detection result by the detection means. 2. The hydraulic system for an industrial vehicle according to claim 1, wherein a supply amount of pressure oil to the cargo handling device is limited by limiting an oil discharge amount. The discharge amount of the pressure oil from the pump can be set to two types of a first discharge amount and a second discharge amount having a smaller flow rate than the first discharge amount, and the occupant detection means can perform the separation. A discharge amount setting means for setting the second discharge amount when a seat state is detected;
The supply amount limiting means controls the operation of the pump so that the pressure oil of the discharge amount set by the discharge amount setting means is discharged, and is set to the second discharge amount by the discharge amount setting means. 4. The industrial vehicle hydraulic system according to claim 1, wherein a supply amount of pressure oil from the pump to the cargo handling device is limited.   The said supply amount restriction | limiting means restrict | limits the supply amount of the pressure oil to the said material handling apparatus by making the rotational speed of the said pump small and restrict | limit the discharge amount of the said pump. The hydraulic system for an industrial vehicle according to any one of 5. Actuate to regulate at least one of supply of pressure oil to the cargo handling device and discharge of pressure oil from the cargo handling device so as to prohibit cargo handling operations based on the operation of the cargo handling device Cargo handling prohibition means,
Cargo handling prohibition control means for operating the cargo handling prohibition means when the absence state is detected by the occupant detection means;
The hydraulic system for industrial vehicles according to any one of claims 1 to 6, further comprising: The cargo handling device includes a lift device that has a single-acting lift cylinder and performs a lifting operation of the load,
As the cargo handling prohibition means, provided with a lowering lock valve mechanism that is provided so as to be connected to the oil chamber of the lift cylinder and is capable of regulating the downward movement of the lift cylinder,
The said cargo handling prohibition control means regulates the operation | movement of the said descent | fall direction of the said lift cylinder by operating the said descent | fall lock valve mechanism, when the said passenger separation state is detected by the said passenger | crew detection means. 8. The hydraulic system for an industrial vehicle according to 7. The cargo handling device has a tilt cylinder, and includes a tilt device that performs a forward / backward tilt operation of a lift device that performs a lifting operation of the load,
As the cargo handling prohibition means, it is provided so as to be connected to the oil chamber of the tilt cylinder, and a forward tilt lock valve mechanism capable of regulating forward tilting action by the tilt cylinder and backward tilting action by the tilt cylinder can be regulated. Comprising at least one of a rearward tilting lock valve mechanism,
The cargo handling prohibition control means regulates the operation of the tilt cylinder by operating the forward tilt lock valve mechanism or the rear tilt lock valve mechanism when the unoccupied state is detected by the occupant detection means. 9. The hydraulic system for an industrial vehicle according to claim 7, wherein the hydraulic system is for industrial vehicles.

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