JPS63233125A - Controller for speed of oil-pressure working machine - Google Patents

Abstract

PURPOSE:To raise the efficiency of scooping operation by calculating the ascending speed of bucket on the basis of the inclining speed of the bucket in a control circuit for a working machine to raise and tilt the bucket by oil pressure. CONSTITUTION:Signals from a boom kick-out switch 8 and signals OB from an angle sensor 9 for bucket are put in the input circuit 4 of a controller 3. Voltage XL and XT based on displacement of a lift operation lever 1 and a tilt operation lever 2 are also put in the circuit 4. On the basis of these signals, calculation is made in an arithmetic circuit 5, and lift output signal YL and tilt output signal YT are sent out from the control circuit 7. On the basis of the outputs, the amount of oil is properly controlled by a lift control electromagnetic proportional valve 11 and a tilt control electromagnetic proportional valve 12 and supplied to a lift cylinder 13 and a tilt cylinder 14.

Description

Detailed Description of the Invention (Field of Industrial Application) This invention relates to a shovel loader, a dozer shovel, and a forklift trunk industrial vehicle, and particularly to an industrial vehicle having a lift device that raises a load using hydraulic pressure, and a tilt device that also tilts the load. It is suitable for use in

(Prior Art) FIG. 5 shows an overall schematic diagram of a shovel loader, which is an example of the field of application of the present invention. In the figure, a bucket C is loaded with earth and sand, a tilt cylinder d is activated to tilt the bucket C toward the vehicle body, and a lift cylinder b is activated to lift a lift arm a upward.

FIG. 3 shows an example of a conventional working machine hydraulic circuit diagram. In the figure, pressure oil supplied from a hydraulic pump e moves a tilt cylinder d by operating a tilt control valve f, and drives a lift cylinder b by operating a tilt control valve valve g.

gl indicates the raised position of lift cylinder b, gz indicates the neutral position, gz indicates the lowered position, and gs indicates the floating position. h is
A boom kick-out electric detent that electrically activates a boom kick-out device (not shown) that automatically stops the load when it rises to an arbitrary preset load height (bucket) C (see Figure 5). .

(Problems to be Solved by the Invention) Figure 4 shows an example of the relationship between the operation and the bucket load when a vehicle equipped with the prior art hydraulic circuit shown in Figure 3 performs work to scoop up earth and sand. In the figure, I
"Lift" in the periods II, IV, and ■ means raising the lift arm a (see Figure 5), and "tilting" in the periods II, IV, and ■ means moving the hacket 1-C (see circle 5) toward the vehicle body. "Dump" in the period (■) means an operation opposite to "tilt." As you can see from the figure, scooping is performed by repeating "lift" and "tilt" to prevent the bucket load from exceeding the maximum hydraulic pressure. The bucket is returned and the object is operated so that it enters the bucket. This dump operation! ! Between JJ and ■.

The vertical load Fv has decreased, which causes the problem of inducing slip in the front tires of the vehicle (t in FIG. 5).

Further, FIG. 4 FC+ is an explanatory diagram of the trajectory of the bucket cutting edge in the case of the scooping operation described with reference to FIG. 4(a). In the figure, the line marked W is the upper surface of the earth and sand that is about to be scooped in, the line marked A is the ideal trajectory of the bucket's cutting edge, and the line marked B is the top surface of the soil that is about to be scooped in. (by the conventional hydraulic circuit).To perform this scooping operation, the operator uses the lift operating lever (n in Fig. 3) and the chill 1 operating lever (Fig. 3). (m) alternately, or
Alternatively, in vehicles equipped with the boom kick-out device (not shown), which is a lift position holding device, scooping can be done by operating only the tilt control lever (m in Figure 3) while holding the lift. I am doing it. Of these two operating methods, the former method requires complicated repetition of lift and tilt operations, and the latter method is superior. However, in the latter operating method, the holding position of the lift control valve g is the maximum lift position,
In the conventional work machine hydraulic system, the tilt operation lever m is
The lift speed when divided by 7 (period ■ in Figure 4 (0)) was too high, making it impossible to control the operating speed of the bucket in the forward and upward directions, making it impossible to scoop enough soil and sand into the bucket. Therefore, there was a big problem in that wasteful operations such as the dump operation during the period V in FIG. 4 (FC) were required. In addition, FIG. 4(b) is a graph explaining the amount of working machine oil supplied in 5 to 4 (al).

(Means and effects for solving the problem) The present invention has been made in view of the above-mentioned problems, and the lift I operating lever and the tilt operating lever each have an electric Turn the lever. The controller consists of an arithmetic circuit that calculates an output signal value based on the input from the electric lever, an output signal holding circuit that holds the output signal for a certain period of time, and a control valve control circuit that outputs the output to the lift control electromagnetic proportional valve. Configure. The lift control electromagnetic proportional valve and the tilt control electromagnetic proportional valve drive the lift cylinder and the tilt cylinder by flowing oil amounts proportional to the signals output from the controller, respectively. This is how the hydraulic work machine speed control device is constructed.

If you operate the tilt I/operation lever to the chill 1 position while the boom kickout signal is being output by the lift operation lever, the output time of the tilt operation lever output signal and the bucket angle change will be determined.

Calculates the lift output signal determined from the output signal calculation function that has been preloaded into the calculation circuit.

When the operation of the tilt operation lever is interrupted, the lift output signal is outputted to the lift control electromagnetic proportional valve for a certain period of time determined by the output signal holding circuit, thereby controlling the lift speed during the scooping operation. This greatly improves work efficiency.

(Example) Examples of the present invention will be described below based on the drawings.

In FIG. 1 (al), the lift operating lever 1 and the tilt operating lever 2 are electric levers that output voltages XL and XT according to lever displacement, respectively, and these lever signals XL and XT and the boom kickout switch 8 The signal θ8 and the signal θ8 from the bucket angle sensor 9 are input into the input circuit 4 of the controller 3, the output signal value is calculated in the arithmetic circuit 5, and the output signal value is held in the signal holding circuit 6 for a certain period of time. The control valve control circuit 7 outputs a lift output signal YL and a tilt output signal YT to a lift control solenoid proportional valve 11 and a tilt control solenoid proportional valve 12, respectively.The lift I control solenoid proportional valve 11 and the tilt control solenoid proportional valve 12 Each.

The amount of oil proportional to the signals YL and YT output from the controller 3 is applied to the lift cylinder 13 and the tilt cylinder 14.
It is designed to be driven by flowing into the air.

Next, the operation of the hydraulic working machine speed control device shown in FIG.
This will be explained with reference to Figures (a) to tc+.

Further, since the external view of the shovel loader shown in FIG. 5 is the same in the embodiment of the present invention, FIG. 5 and the reference numerals in this figure are also referred to. 2 (al and (bl) respectively correspond to FIG. 4 (fbl and (C1) of the prior art, the same reference numerals indicate the same things, and C in FIG. 2 (bl) corresponds to FIG. This is a specific example of the trajectory of the bucket blade edge. Now, the hegesaw LC is penetrated into the object W such as earth and sand, and the lift operating lever 1 is moved to the boom kick-out position (Fig. 1 (a)
1), move the cutting edge of the brush saw l-c forward toward the object W, and use the vehicle's tire driving force to move the blade saw l to the target object W.
-c is pushed in, and when the horizontal resistance force (FH in fat in FIG. 4) increases and pushing becomes impossible, the tilt operation lever 2 is operated to scoop the object W into the bucket C. If the operator determines that the scooping amount is insufficient by operating the tilt I/operating lever 2 at this time, the tilt operating lever 2 is returned to the neutral position. Here, the operating time △T of the tilt operation lever 2, which is determined by the type of object W, the road surface condition, the inclination around 1, the engine throttle opening, the proficiency level of the operator, and the work cycle time, and the amount of change in the inclination of the bucket c. According to Δθ, a lift output signal YL calculated by a function preloaded into the calculation circuit 5 is output to the lift control electromagnetic proportional valve 11, and the lift arm a is raised.

The relationship between lever operation and work machine oil flow rate during this series of scooping operations is as shown in Figure 2 (al).

The amount of oil in the lift cylinder 13 during scooping is reduced compared to the prior art No. 4M(b).

The lift speed can be controlled to match the tilt speed. By automatically controlling the lift speed during scooping work in this way, scooping work can be easily performed by operating only the tilt operation L/bar 2, and the lift speed can be matched to the tilt speed. , bucket) c into the target object W is directed toward the direction with higher penetration efficiency, as shown in Fig. 2 (
The trajectory of the bucket cutting edge as shown in C in b) is extremely close to the ideal trajectory A, which improves work efficiency and improves the dump tip trajectory as shown in Figure 4 (■ in C1), which is the conventional technology. There is also no need for an operation to fold the object W into the bucket c.

In addition, FIG. 1 (C1 is an example of calculating the lift speed after the tilt operation is released during the boom kickout operation, and the lift output signal Y is calculated from the average tilt angular velocity θ°8 during the tilt operation.
is obtained and output to the lift control electromagnetic proportional valve 11.

Further, the holding time of the lift output signal in the signal holding circuit 6 is set to be longer than the time for releasing the operation of the tilt operating lever during normal work.

Further, a flowchart of calculations in the calculation circuit 5 is shown in FIG. 11++.

(Effect of the invention) This invention is constructed as described above in detail.

There is no need for the complicated operation of alternately operating the lift control lever and tilt control lever, making scooping work easier by operating only the tilt control lever, and the bucket tip trajectory is extremely close to the ideal trajectory. Therefore, unnecessary operations such as dump operations using the tilt operation lever are not necessary, and work efficiency is greatly improved. Furthermore, since the dumping operation is not required, the bucket vertical load is reduced and the front tires do not slip, which is a great advantage.

[Brief explanation of the drawing]

FIG. 1(a) is a circuit diagram schematically showing a hydraulic working machine speed control device according to an embodiment of the present invention. Fig. 1 (bl is a flowchart of controller output signal calculation, Fig. 1 fc) is an example of lift output signal calculation,
Figure 2 ta+ is a graph of a specific example showing the amount of working machine oil supplied, Figure 2 (bl is an explanatory diagram showing the trajectory of the bucket cutting edge, Figure 3 is a conventional hydraulic circuit diagram 1, (
b) and tc+ are the operation method 1 for the conventional scooping operation, the amount of oil supplied to the work machine, and the locus of the bucket cutting edge, respectively. FIG. 5 is an external view of the shovel loader. 1...Lift operation lever. 2...Tilt operation lever, 3...Controller. 11...Lift control solenoid proportional valve. 12...Tilt control solenoid proportional valve. 13...Lift cylinder, 14...Tilt cylinder. Patent Applicant Komatsu Ltd. Agent (Patent Attorney) Osamu Matsuzawa 1 TI! J(b) U Child Ruto Kakushushi Susatsu (18 Figure 1 (c) Procedural Amendment April 15, 1986)

Claims (1)

[Claims] In a hydraulic system for a work machine that raises and tilts a bucket using hydraulic pressure, an electric lift operation lever and a tilt operation lever output an electric signal corresponding to lever displacement; boom kickout is activated by inputting the electric signal. a controller that calculates the rising speed of the bucket based on the bucket tilting speed during the bucket tilting operation and outputs an electric signal; a lift control electromagnetic proportional valve and a tilt control that flow an amount of oil corresponding to the electric signal to the lift cylinder and the tilt cylinder; A hydraulic working machine speed control device comprising: an electromagnetic proportional valve;