JPH075275B2 - Vehicle control valve control method - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a control method for controlling a control valve of a cargo handling cylinder of a vehicle such as a forklift, for example, a lift cylinder or a tilt cylinder, and more specifically, a cargo handling operation of a vehicle. The present invention relates to a control method for safely and easily.

(Prior Art) Conventionally, as an example of control of a control valve for driving a lift cylinder of a forklift, there is one disclosed in Japanese Utility Model Laid-Open No. 60-107405.

According to the publication, the hydraulic circuit for controlling the control valve 2 for the lift cylinder 1 as shown in the overall configuration diagram of FIG. 2 is such that the pressure oil from the hydraulic pump 3 is a shunt valve from the discharge pipe line 4. Main pipe line 6 on the side of control valve 2 through 5
And the PS pipe line 7 for power steering. An oil chamber 8 for pilot operation is formed on one side of the control valve 2. A pilot piston 9 is slidably fitted in the oil chamber 8 and the pilot piston 9 is a spool of the control valve 2. Concatenated with 10. The spool 10 is always held in the neutral position by the spring 11.

Reference numeral 12 is a pilot inflow conduit for introducing pilot pressure oil to both sides of the oil chamber 8 with the pilot piston 9 interposed therebetween,
It is connected so as to introduce the hydraulic pressure of the PS line 7.
A pressure reducing valve 13 for protecting the downstream portion and stabilizing the pilot oil pressure is provided in the middle of the pilot inflow conduit 12.
Further, normally closed electromagnetic on-off valves 14A and 14B for ascending and descending are provided on the downstream side of the branch point of the pilot inflow conduit 12. Reference numeral 15 denotes a pilot drain pipe line for leading the pilot pressure oil in the oil chamber 8 to a tank or a return pipe line, which communicates with both sides of the oil chamber 8 with the pilot piston 9 interposed therebetween, and throttle valves (orifices) respectively. Has 16.

17 is a cargo control lever for remote control installed near the driver's seat, and 18 is the solenoid opening / closing valve 14
It is a controller for driving and controlling A and 14B, and these constitute a valve control device. Then, the cargo handling operation lever 17 has a tilting direction (operation direction).
Then, the controller 18 outputs a signal of the tilt angle, while the controller 18 supplies the drive current corresponding to the signal to the electromagnetic opening / closing valve 14A or 1A.
An electric circuit is formed to energize 4B.

Therefore, in the illustrated neutral state, when the lever of the cargo handling operation lever 17 is tilted, for example, to the upside, signals of the tilting direction and tilt angle are output, and the controller receiving it
Since 18 supplies the drive current according to the tilt angle to the solenoid valve 14A on the rising side (right side in the drawing) corresponding to the tilt direction,
The electromagnetic opening / closing valve 14A is operated. As a result, a controlled amount of pilot pressure oil flows into the oil chamber 8, and pressure is generated because the outlet side of the pilot pressure oil is controlled by the throttle valve 16, and the spool is passed via the pilot piston 9.
10 is switched to the rising side. At this time, the spool 10 is a pilot pressure generated in the oil chamber 8 and a spring against the pilot pressure.
The position of the spool 10 is controlled by adjusting the operation amount of the electromagnetic opening / closing valve 14A, that is, the flow rate of the pilot pressure oil flowing into the oil chamber 8, so that the position of the spool 10 is controlled. be able to. That is, the rising speed of the lift cylinder 1 is appropriately controlled by changing the inclination angle of the lever of the cargo handling operation lever 17. It should be noted that the same operation is performed during the downward operation.

In the hydraulic circuit configured as described above, when the operator carelessly touches the cargo handling operation lever 17, the lift cylinder 1
As a means for preventing the operation of the lift cylinder 1 due to this inadvertent operation, a safety switch is provided in the controller 18 of the hydraulic circuit as shown in FIG.
A control valve control method for cargo handling such as a forklift has been adopted in which the lift cylinder 1 cannot be operated by the cargo handling operating lever 17 unless the safety switch 19 is additionally connected to the valve 19.

(Problems to be Solved by the Invention) According to the conventional cargo handling control valve control method for a forklift or the like, when operating the cargo handling lever 17, the safety switch 19 must be always pressed. However, there was a problem that the cargo handling operation was inconvenient and difficult to carry out.

Therefore, in the present invention, a seat switch that outputs a signal when the operator is seated on the operator seat is provided,
The technical problem to be solved is to enable safe cargo handling operation of a vehicle when a seating signal is output from the seat switch.

(Means for Solving Problems) Technical means for solving the above problems are provided with a pilot pressure oil pipe line for introducing pilot pressure oil into a spool of a control valve for controlling a hydraulic actuator, and a pilot pressure oil pipe line corresponding thereto. The two pilot drain lines for deriving the pilot pressure oil are operated on either or both of them, and the operation signal corresponding to the operation of the cargo handling operation means and the fact that the operator is seated on the operator seat are detected. Controls the cargo handling control valve in the hydraulic control circuit of the cargo handling control valve of a vehicle provided with an opening / closing valve that is opened / closed by an electric signal output from the control device based on a signal from a seat switch that outputs a signal. When the seating signal is output from the seat switch, the control method for The control signal corresponding to the above is output to the on-off valve, the cargo handling operation means is operated before the seating signal is output from the seat switch, and the seating signal is output from the seat switch during the operation of the cargo handling operation means. If done,
First, a low level control signal is output to the on-off valve, and the output level of the control signal is gradually increased to a level corresponding to the operation amount of the cargo handling operation means during the operation. .

(Operation) According to the control valve control method for cargo handling of the vehicle, when the operator is seated on the operator seat and the cargo handling operation means is operated in a state where the seating signal is output from the seat switch, A control signal corresponding to the operation of the cargo handling operation means is output to the on-off valve to control the cargo handling control valve to drive and control the hydraulic actuator.

In addition, when the cargo handling operation means is operated before the seating signal is output from the seat switch, the operator sits on the operator seat during the operation of the cargo handling operation means, and the seating signal is output from the seat switch. , The control device first outputs a control signal of a low output level to the on-off valve, and thereafter gradually changes the output level of the control signal to a level corresponding to the operation level during the operation of the cargo handling operation means. By raising it, the hydraulic actuator is smoothly driven and controlled.

(Example) Next, the Example of this invention is described according to drawing.

In the present embodiment, a hydraulic circuit having the same structure as the hydraulic circuit for controlling the control valve for driving the lift cylinder 1 of the conventional forklift shown in FIG. The control valve control method for facilitating is shown. Therefore, the explanation numbers used in the description of the present embodiment are the same as the explanation numbers shown in FIG. However, in the case of the present embodiment, a seat switch that outputs a seating signal when the operator is seated on the operator seat is used without using the conventional safety switch.

FIG. 1 is an electrical control system diagram of this embodiment. As shown in the figure, the controller 18 is connected to an operation lever, that is, a cargo handling operation lever 17 that outputs a voltage signal corresponding to an operation inclination angle, and the voltage signal output from the operation lever 17 is an A / D converter 31. Entered in. An A / D converter 31 is provided to convert the voltage signal into a digital signal, and the digital signal output from the A / D converter 31 is a CPU (central processing unit) 33 that constitutes a microcomputer via an input interface 32. Entered in. Further, the input interface 32 of the controller 18 is connected to a seat switch 19 that outputs a seating signal when the operator is seated on the operator seat. A random access memory RAM 34, a read-only memory ROM 35, and a clock 36 are connected to the CPU 33, and the read-only memory ROM 35 stores a control program for controlling the electromagnetic opening / closing valves 14A, 14B and the like.

An output interface 37 is connected to the output side of the CPU 33, and the control signal output from the CPU 33 is output to each of the solenoid valve 14A drive circuit 38 and the solenoid valve 14B drive circuit 39 via the output interface 37. The solenoid valve 14A drive circuit 38 and the solenoid valve 14B drive circuit 39 are connected to the solenoid on-off valves 14A and 14B, respectively, and supply a drive current to the solenoid on-off valves 14A and 14B.

Next, the operation of this embodiment will be described with reference to the flowchart shown in FIG.

The power switch (not shown) is turned on and the controller
When power is supplied to 18, the CPU 33 initializes the internal register, the input / output unit, etc. as shown in step S1. In step S2, the CPU 33 determines whether or not the operation level of the cargo handling operation lever 17, that is, the inclination of the lever 17 is within a range of a slight inclination angle (neutral width) preset for safe operation. Even if the cargo handling operation lever 17 is tilted within the above neutral width range, the CPU 33 causes the electromagnetic opening / closing valve 1 to operate.
The range of the tilt angle is set so that the control signal for controlling 4A and 14B is not output.

If the decision result in the step S2 is NO, as shown in the step S3, the soft start, that is, when the inclination of the cargo handling operation lever 17 is operated beyond the neutral width, the CPU 33 causes the electromagnetic opening / closing corresponding to this operation angle. A soft start flag is set to set a soft start function of gradually increasing the level of the output signal without increasing the valve drive signal suddenly. In the next step S4, the CPU 33 sets the data for making the current flowing through the solenoid opening / closing valve 14A or 14B zero, and then proceeds to step S6.

On the other hand, if the decision result in the step S2 is YES, as shown in a step S5, the soft start flag is turned off, and then the process proceeds to the step S6. In step S6, it is determined whether or not the seat switch 19 is turned on and the seating signal is output, and when it is determined that the switch 19 is turned on, in step S7, whether the soft start flag described above is set or not. Determine whether or not. If the decision result in the step S7 is NO, in a step S8, the CPU 33 drives the solenoid valve 14A drive circuit 38 in accordance with the inclination of the cargo handling lever 17,
Alternatively, the value of the drive current supplied from the solenoid valve 14B drive circuit 39 to the solenoid on-off valve 14A or the solenoid on-off valve 14B is calculated, and in step S9, a control signal corresponding to the drive current value B calculated in step S8 is calculated. Is output, and the solenoid on-off valve 14A or 14B corresponding to the inclination of the cargo handling lever 17 is output.
After driving, proceed to step S15.

On the other hand, if the decision result in the step S7 is YES, in the step S10, the updated drive current obtained by adding a constant current value α to the value of the drive current currently output to the electromagnetic on-off valve 14A or the electromagnetic on-off valve 14B. Calculate the value A. Next, in step S11, the drive current value B of the electromagnetic on-off valve 14A or the electromagnetic on-off valve 14B corresponding to the current inclination of the cargo handling lever 17 is calculated. In the next step S12, the updated drive current value A and the calculated drive current value B of the solenoid on-off valve 14A or 14B corresponding to the current inclination of the cargo handling operation lever 17 are calculated.
And make a big or small judgment. If it is determined in step S12 that A ≧ B, the soft start flag is turned off in step S13, and then step S9 is performed.
Move to. Further, in the determination of step S12, A ≧
If it is determined that it is not B, in step S14, the CPU33
Outputs a control signal for energizing the solenoid valve 14A or 14B with the calculated current value A, and then, in step S15.
Proceed to. In step S15, it is determined whether the tilt of the cargo handling lever 17 is within the neutral width. If the decision result in the step S15 is YES, the process returns to the step S5, while if the decision result is NO, the process returns to the step S6.

As described above, steps S2 to S15 of the above flowchart are performed.
By repeating the above, when a seating signal is output from the seat switch 19, it is possible to perform a cargo handling operation by operating the cargo handling operation lever 17, and the cargo handling operation lever 17 is operated before the seating signal is output from the seat switch 19. When the seating signal is output from the seat switch 19 during the operation of the cargo handling operation lever 17, the solenoid opening / closing valves 14A, 14B are set to the level of the control signal corresponding to the operation level of the cargo handling operation lever 17 during the above operation. By gradually increasing the output level for the cargo handling operation, the cargo handling operation is performed safely and smoothly.

In the above embodiment, the operated cylinders operated by the solenoid opening / closing valves 14A and 14B are lift cylinders.
The same applies to the case of the tilt cylinder. Further, although an example of a forklift is shown as the type of vehicle, it can be applied to other industrial vehicles provided with a cargo handling device, agricultural vehicles, and the like. Further, instead of the solenoid on-off valves 14A and 14B, on-off valves other than the electromagnetic type may be used.

(Effects of the Invention) As described above, according to the present invention, an operator sits on the operator seat when loading and unloading a vehicle such as a forklift.
When the seating signal is output from the seat switch, the cargo handling operation is enabled, and the cargo handling operation means is operated before the seating signal is output from the seat switch, and the seating switch outputs the sitting signal during the operation. In such a case, the control is performed so as not to perform the rapid cargo handling operation, so that the cargo handling operation of the vehicle can be safely and easily performed.

[Brief description of drawings]

FIG. 1 is an electric control system diagram of one embodiment of the present invention, and FIG.
FIG. 3 is a hydraulic circuit diagram, and FIG. 3 is a flow chart diagram for explaining the operation. 1 …… Lift cylinder 2 …… Control valve 3 …… Hydraulic pump 9 …… Pilot piston 10 …… Spool 14A, 14B …… Electromagnetic on-off valve 17 …… Cargo handling lever 18 …… Controller 19 …… Sheet switch 33 …… CPU

Claims (1)

[Claims] 1. A pilot pressure oil line for introducing pilot pressure oil into a spool of a control valve for controlling a hydraulic actuator, and two pilot drain lines for corresponding pilot pressure oil leading out. , Either one or both, based on the operation signal corresponding to the operation of the cargo handling operation means and the signal from the seat switch that detects that the operator is seated on the operator seat and outputs the seating signal from the control device. A control method for controlling the cargo handling control valve in a hydraulic control circuit of a cargo handling control valve of a vehicle provided with an opening / closing valve that is operated to be opened / closed by an output electric signal, wherein the seating signal is transmitted from the seat switch. When being output, a control signal corresponding to the operation of the cargo handling operation means is output to the on-off valve. In the case where the cargo handling operation means is operated before the seating signal is output from the seat switch, and the seating signal is output from the seat switch during the operation of the cargo handling operation means,
First, for cargo handling of a vehicle, which controls to output a low-level control signal to the on-off valve and gradually increase the output level of the control signal to a level corresponding to the operation amount of the cargo handling operation means during the operation. Control valve control method.