JPS62130999A - Boom controller for service car - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

Detailed Description of the Invention (Industrial Field of Application) The present invention includes a rotating base having a boom that is moved up and down by the operation of a hydraulic actuator, mounted on a traveling base, and supplying hydraulic oil to the hydraulic actuator. The present invention relates to a work vehicle that is provided with an electric proportional control valve for controlling exhaust gas and has manual input means for arbitrarily setting a first control signal to the electric proportional control valve.

(Prior Art and Problems) Work vehicles such as crane trucks and aerial work vehicles are equipped with safety devices to prevent dangerous situations such as accidents of the work vehicle falling during work. This safety device compares a limit value set for each working state with an actual value corresponding to this limit value, and stops the operation of the work vehicle when the actual value becomes equal to the limit value. However, with this safety device, for example, if the boom reaches the stopped state while it is rapidly lowering, the more the boom is extended, the more likely the sudden stop of the boom will cause an excessive shock to each structural part of the work vehicle. This could lead to serious accidents such as destruction or overturning of the work vehicle, or even the fall of a passenger on the packet provided at the tip of the boom.

(Objective of the Invention) An object of the present invention is to obtain a boom control device for a working vehicle that can smoothly stop the boom regardless of the extent of extension of the boom.

(Means for solving problems) In order to achieve the above object, the present invention has been made.

A swivel base having a boom that is raised and lowered by the operation of a hydraulic actuator is mounted on a traveling base, and an electric proportional control valve for controlling supply and discharge of hydraulic oil to the hydraulic actuator is provided, and the electric proportional control valve In a work vehicle equipped with manual input means for arbitrarily setting a first control signal to a vehicle.

Actual value detection means for detecting an actual value corresponding to a limit value determined for each working condition in order to prevent dangerous conditions such as overturning of a working vehicle; limit value storage means for storing said limit value; and said limit. a comparison means for comparing the value and the actual value, a boom length detection means for detecting the extended state of the boom, and a second output signal for outputting to the electric proportional control valve according to output signals from the comparison means and the boom length detection means. The control signal includes a storage means for storing a control signal, and a control signal output means for comparing the @11 control signal and the second control signal and outputting the smaller one to the electric proportional control valve. be.

(effect) Next, this invention will be explained in detail.

When the operator issues a first control signal using the manual input means, the signal is sent to the control signal output means.

On the other hand, the actual value is detected by the actual value detection means, and this actual value is compared with the limit value stored in the limit value storage means by the comparison means. Further, the boom length detection means detects the extended state of the boom. The comparison result compared by the comparison means is sent as a signal, and the extension state of the boom detected by the boom length detection means is sent as a signal to the storage means, and a second control signal determined by these signals is sent from the storage means. is sent to the control signal output means. The control signal output means compares the first control signal and the second control signal and selects whichever is smaller (smaller means that the opening degree of the electric proportional control valve is smaller). In response to this control signal, the electric proportional control valve opens and the hydraulic actuator is driven, thereby determining the control speed of the boom.

(Example) Next, the present invention will be explained based on examples.

FIG. 1 is a block diagram of a boom control device for a working vehicle showing one embodiment of the present invention.

In FIG. 1, reference numeral 1 denotes a manual input section for arbitrarily setting a first control signal Vl to an electric proportional control valve 8, which will be described later, by manual operation such as lever operation or joystick operation. 2 is an actual value detector that detects the actual value corresponding to the limit value determined for each working condition in order to prevent the work vehicle from falling over. 1. If the work vehicle is a crane truck, the boom This corresponds to a detector for detecting the load suspended from the tip of the boom or the moment response value, etc. that acts on the boom due to this load, and if the work vehicle is an aerial work vehicle, it is a detector installed at the tip of the boom. This corresponds to a detector for detecting the working position of the packet. 3 is a limit value storage device that stores the limit value.

This stored value is determined for each condition such as boom length, boom elevation angle, etc., and a predetermined stored value is selected based on a detection signal from a detector that detects these conditions. A comparator 4 outputs a value obtained by dividing the actual value signal from the actual value detector 2 by the limit value signal from the limit value storage 3. 5 is a boom length detector. In this embodiment, the boom is a telescopic 4-stage telescopic boom that extends sequentially from the boom cylinder on the proximal end side. It is designed to detect each of the four stages of all top pool cases. Reference numeral 6 denotes a function generator which, as shown in FIG. , all cases up to the third pool follow the characteristic line shown in , and all cases up to the second pool follow the characteristic line shown in line Ls, and the line follows the line when the pool completely collapses.

The second control signal v1 is output according to the characteristic line shown in FIG. In these characteristic lines, the horizontal portion indicates that the second control signal Vs has a signal value corresponding to maximizing the valve opening degree of the electric proportional control valve 8, which will be described later.

The signal value decreases as it decreases downward, and when it reaches zero, it indicates that the valve opening degree becomes zero. When these characteristic lines are followed, the boom can be stopped smoothly when the actual value reaches the limit value and the boom is stopped.

7 is a control signal output section that outputs the first signal from υ1 manual input section 1.
The control signal v1 is compared with the second control signal v from the function generator 6, and the smaller one is outputted to the electric proportional control valve 8, which will be described later. 8 is an electric proportional control valve, and the valve 8 is a hydraulic actuator (double-acting hydraulic cylinder or hydraulic motor) that controls the raising and lowering of the boom using oil discharged from the pump.
It is inserted into the oil path that supplies and discharges the oil.

As the control signal from the control signal output section 7 becomes larger, the valve opening degree of the electric proportional control valve 8 becomes larger. Note that ■ is a circuit diagram in which an electric proportional control valve is provided.

With the above configuration, even if the first control signal V from the manual input unit 1 exceeds a value that ensures smooth stopping of the boom when the actual measurement value approaches the limit value, the second control signal Since the signal V is input to the electric proportional control valve 8, the hydraulic actuator is smoothly stopped when the measured value reaches the limit value.

In the above embodiment, the number of characteristic lines stored in the function generator 6 was four, but when the boom length is the intermediate boom length, for example, 1 is the characteristic line for all cases up to the second poom, and the characteristic line for the top poom is When it is slightly more extended than the second pool.

The second control signal for this intermediate boom length may be determined by interpolation based on the lines La and Ll.

Furthermore, since the speed of the hydraulic actuator is proportional to the opening degree of the electric proportional control valve and the flow rate of oil passing through the valve, the speed of the hydraulic actuator is proportional to the rotation speed of the engine that is the drive source of the pump that discharges the oil. Capture the flow velocity 1. The number of revolutions of this engine is detected directly or indirectly, and the number of revolutions of this engine is high.

It goes without saying that if the function generator generates a characteristic line in which the starting point of regulating the opening degree of the electric proportional control valve differs depending on the value of the opening of the electric proportional control valve, more effective control in terms of work efficiency will be possible.

Furthermore, the lodging speed itself of the boom is detected from the change in the heave angle, and the lodging speed of the boom is divided into three stages, for example, high speed, medium speed, and low speed. Alternatively, a characteristic line as shown in FIG. 2 may be generated by a function generator.

Next, the present invention will be explained using a microcomputer. FIG. 3 is a configuration diagram in this case.

In Fig. 3, 1 is a manual input section, 2 is an actual value detector,
5 is a boom length detector;

Refers to the same thing as explained in FIG.

23 is a working state detector. 9 is the manual input section 1;
．． An input unit converts the analog signals output from the actual value detector 2, working condition detector 23, and boom length detector 5 into digital signals and inputs the digital signals to the microcomputer. This is a CPU that performs calculations and control. 11 is a program ROM that stores processing procedures for calculation and control of the CPU 10;
2 is the line Lt*Lm, Ls-L in FIG. 2 mentioned above.
There is a data ROM shown in a, and a RAM 13 temporarily stores input values and the like. Further, 14 is an output unit that converts the output signal from the microcomputer M from a digital signal to an analog signal, and 15 is a pass line that connects each component of the microcomputer M.

Next, the process shown in FIG. 3 will be explained according to the flowchart shown in FIG.

First, step (the word step will be omitted below) 8
1, the actual value detected by the actual value detector 2 is taken in through the input crab unit 9, and the actual value is extracted.
Temporarily stored in M13. Next, S, the working status detector 2
The working status signal outputted by 3 is read out as the limit value of intake via the input unit 9, and is temporarily stored in the RAM 13. Next, in F1a, the actual value and the limit value are taken out from the RAM 13, the actual value is divided by the limit value, and this calculated value is temporarily stored in the RAM 13. Next 84
The boom length detected by the boom length detector 5 is taken in through the input unit 9, and the boom length is read out and temporarily stored in the RAM 13. Next, RAM 1 in Els
The calculated value from 3 to 8 m and the boom length at S4 are taken out, and the second control signal "im" corresponding to these is sent as data RO.
It is read from M12 and temporarily stored in RAM13. Next, at 13m, the signal from the manual input section 1 is taken in via the input unit 9, and the first control signal vI is read out.

Temporarily stored in RAM 13. Next, in ST, Fj A
The first control signal vl and the second control signal V are extracted from M13 and compared. Then, at Sa, the first control signal V,
When the control signal v exceeds the snow, the second control signal v is applied, and when the second control signal V exceeds the first control signal V, and when it exceeds the snow, the first control signal vI is applied to the crab knit 1.
5 to the electric proportional control valve 8. Therefore, when the measured value approaches the limit value, that is, when the measured value is in the lower right region of the characteristic lines Ls, Ls, Ls, L4 shown in FIG. 1st
When the control signal v1 exceeds the second control signal v3, the second control signal v is input to the electric proportional control valve 8, so that when the actual value reaches the limit value, the hydraulic actuator is smoothly stopped. Effects of the Invention) In this invention, even if the working vehicle reaches the limit state determined to prevent the overturning accident of the working vehicle due to the collapse of the boom, a shudder at the time of stopping occurs depending on the length of the boom. Since the lodging speed of the boom is controlled to slow down beforehand, sudden stops will not occur and work safety can be sufficiently ensured.

[Brief explanation of drawings]

FIG. 1 is a block diagram of a boom control device for a work vehicle showing an embodiment of the present invention, FIG. 2 is a graph explaining deceleration control, and FIG. FIG. 4 is a flowchart of the microcomputer shown in FIG. 3. FIG. 8; Electric proportional control valve % 1; Manual input part 2; Actual value detector, 3; Limit value memory 4; Comparator, 5; Poom length detector, 6; Function generator, 7; Control signal output part

Claims (1)

[Scope of Claims] A swivel base having a boom that is raised and lowered by the operation of a hydraulic actuator is mounted on a traveling base, and an electric proportional control valve is provided to control supply and discharge of hydraulic oil to the hydraulic actuator. In a work vehicle equipped with a manual input means for arbitrarily setting the first control signal to the electric proportional control valve, a limit value is set for each work state in order to prevent dangerous situations such as the work vehicle falling over. an actual value detection means for detecting an actual value corresponding to the limit value, a limit value storage means for storing the limit value, a comparison means for comparing the limit value and the actual value, a boom length detection means for detecting the extension state of the boom, and the a storage means for storing a second control signal to be outputted to the electric proportional control valve according to the output signal from the comparing means and the boom length detecting means; A boom control device for a work vehicle, comprising control signal output means for outputting the smaller of the two to the electric proportional control valve.