JPS5916076B2 - Automatic feed control device for excavator - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an automatic feed control device for an excavator that can automatically control cutting conditions, that is, cutter rotation speed and cutter feed rate when cutting rocks with constant motion force. .

In general, in an excavator such as a tunnel excavator having a rotary cutter, cutting conditions are determined by a combination of the cutter rotational speed N and the cutter feed rate f with respect to the hardness of the rock.

Assuming that the number of revolutions of the cutter in the excavator is N1, the feed rate of the cutter is f1, the depth of cut of the pick in the cutter is δ, the circumferential speed of the pick's cutting edge is V1, and the pitch of the pick on the cutting line is P, then between these There is a relationship shown in the following equation (where P
, π, and D are constants).

Therefore, in order to keep the depth of cut δ constant, it is necessary to keep f/N constant.

In order to make maximum use of the cutting power, an excavator is equipped with a cutting mechanism configured so that the product of the rotational torque and rotational speed of the cutter is constant as shown in Fig. 5 using a constant dynamic force control method. If you do not adjust the feed rate on the machine,
During cutting, when the rock hardens and the torque increases, the cutter rotational speed N decreases inversely proportionally, and at the same time, the cutting depth δ increases according to the above equation. As the penetration depth increases, overtorque immediately occurs.

On the other hand, if the feed speed f is configured to change in proportion to the cutter rotation speed N, then 1. Since the depth of cut δ is constant, when the hardness of the rock increases, the number of revolutions N of the cutter decreases and at the same time the feed rate f also decreases, and the depth of cut δ remains the same as the initial value.

However, since the hardness of the rock is increasing, the torque will increase and be balanced within its limits, but if the hardness changes significantly, overtorque will occur and the operation of the automatic control system will likely become unstable. .

Therefore, if the configuration is such that f/N, that is, the depth of cut δ, decreases at the rate that occurs when the cutter torque T increases and the rotational speed N decreases, stability (/automatic control system can be obtained.

For example, when the cutting depth δ is to be linearly decreased as the rotational speed N is decreased, the following equation holds true (see FIG. 6).

(see FIG. 7), each constant may be set so as to satisfy the relationship of equation (1).

However, since it is difficult to predict the optimal relationship between f and N based on the properties of the rock, etc., the constant in equation (1) is set to 1 or 1 depending on the properties of the rock. 2. It is desirable to make 3 variable.

SUMMARY OF THE INVENTION An object of the present invention is to provide an automatic feed control device for an excavator that can change its control continuously or stepwise by electrical means.

Next, the present invention will be explained in detail using illustrated examples.

The drawing shows an example of the present invention, in which a loading device 10 having a scraping arm 9 and a conveyor 11 connected to the rear thereof are fixed to a track type vehicle body 8, and the conveyor There is a turning conveyor 1 at the rear of 11.
A swing frame 13 is attached to the vehicle body 8 and is rotated around a vertical axis. The strut body 14 is the revolving frame 1
It is fixed to the front part of 3 with a clamp 15.

Both ends of the strip 14 are connected to a piston rod 17 of a swinging hydraulic cylinder device 16, and the hydraulic cylinder device 16
The cylinder 18 in is fixed to the conveyor frame,
The rotating frame 13 is configured to be able to pivot by shortening one hydraulic cylinder device and extending the other hydraulic cylinder device.

The base end of a cutter arm 19 is pivotally attached to the front part of the swing frame 13 by a horizontal shaft 20, and the tip side of the cutter arm 19 and the swing frame t, 13 are connected via an elevation hydraulic cylinder device 21. The liquid feeding port and liquid suction port of the feeding variable displacement pump 6 driven by the electric motor 22 and both ends of the cylinder 23 in the hydraulic cylinder device 21 are connected by liquid passage pipes 24 and 25. Liquid pipe 24゜2
A cutter feed rate detection device 4 consisting of a stop switching valve 26 and an electric flow rate measuring device is interposed in the cutter feed rate detection device 5 .

Also, the cylinder 18 in the swing hydraulic cylinder device 16
A cutter feed speed detection device 4 consisting of a stop switching valve 26' and an electric measuring device is also interposed in the overnight pipes 24' and 25' connecting both ends of the feed variable displacement pump 6 to the feed variable displacement pump 6. There is.

A cutter drive shaft 28 to which a cutter 1 having a large number of picks 27 on its circumferential surface is fixed is rotatably attached to a cutter arm 19, and is driven by a cutter variable displacement pump 29 driven by the electric motor 22. A liquid supply port and a liquid drain port of a constant volume hydraulic motor 30 fixed to the cutter arm 19 are connected to the liquid supply port and liquid suction port through a liquid supply pipe 31 and a return pipe 32, and the cutter is driven by the hydraulic motor 30. The cutter 1 is configured to be rotated via a shaft 28.

The cutter variable displacement pump 29 is equipped with a constant output control device 33, and the feed variable displacement pump 6 is equipped with a manual lever 34 for manually adjusting the displacement or switching to automatic adjustment. An electric rotation speed detection device 2 consisting of a tacho generator driven by the hydraulic motor 30 is connected to an input terminal of a function generator 3 that generates a function of the rotation speed N of the cutter 1. 3 and the output terminals of each of the feed rate detection devices 4 and 4' are connected to the input terminal of a servo amplifier 5, and the output terminal of the servo amplifier 5 is connected to a variable displacement pump 6 for feeding. It is connected to an input terminal of a flow rate regulating servo motor 7 that controls the flow rate of the flow rate.

The function generator 3 shown in FIG.
This is an example of a device that generates a function of 1N2+ to 2N+3 to
The output terminal of 5.36 is connected to the input terminal of a multiplier 38, the output terminal of the multiplier 38 and the output terminal of the amplifier 37 are connected to the input terminal of the adder 39, and The output terminal and the output terminal of the feed rate detection device 4° 4' are connected to the input terminal of the servo amplifier 5.

Each variable displacement pump 6.29 is driven by the electric motor 22, and the cutter variable displacement pump 29 is controlled by the constant output controller 33 to adjust the hydraulic pressure P (kg/i) x oil amount (l/m1).
The rotation speed N of the hydraulic motor 30 which is controlled so that n) is constant and is driven by the cutter variable displacement pump 29 is measured by the rotation speed detection device 2, and the measurement signal Xi is sent to the amplifier 35. .36 respectively increased in width
.

1=C1Xi, Xo2-C2Xi, Xo3-C3Xi, and then X by the multiplier 38.

=X01 XX02=C1C2Xi2=CX i2 The output and bias C4 are added in the adder 39 to create a reference value of X = CX i2+ Ca Servo motor 7 drives (speeds up or decelerates)
Then, the amount of liquid sent to the hydraulic cylinder device for elevation and rotation, ie, the value of f, is determined.

Further, the feed speed detection devices 4, 4' feed back the measurement signal yi corresponding to the actual flow rate to the servo amplifier 5, and operate so that a deviation O is obtained by comparing it with the set value of f.

The relationship between the values of input f and N is based on the above three variables.
．． 2. By setting 3, it can be programmed in any way, and in simple cases, it can be controlled step by step by creating several fixed programs and switching between them.

In this case as well, in order to obtain the most ideal relationship between f and N,
It is necessary to change the values of C1 to C4, so C1
, C2, C3, and C4 using adjustment knobs 40 to 4, for example.
The configuration is such that it can be adjusted by operating 3.

FIG. 6 shows an example of this, and the switching of the three patterns a, b, and c shown in the graph of δ:N is based on the constant 1. 2. This is done by switching 3.

Note that several circuits with fixed constants may be switched.

Further, as means for switching from automatic operation to manual operation, the variable displacement pump 6 for feeding is provided with an automatic circuit that is linked to the manual lever 34, and in the case of manual operation, the circuit of the servo motor 7 is cut off. should be adopted.

When carrying out this invention, as a cutting tool, a large number of bumps 27 are attached to the front surface of a disc or cylindrical cutter body 44 fixed to a cutter drive shaft 28, as shown in FIG. A cutter arm 19 rotatably supporting the cutter drive shaft 28 may be moved in the longitudinal direction of the cutter drive shaft 28 by a hydraulic cylinder device 45. In the above-mentioned actual case, the cutter is rotated by a hydraulic motor, but in this invention, the cutter is mechanically rotated by an electric motor without using hydraulic pressure. It can also be implemented when driving via a transmission mechanism.

When carrying out the present invention, the function generator 3 may have any structure other than that shown in the drawings.

According to this invention, in an excavator that rotates a cutter 1 and feeds the cutter 1 to cut rock by a drive device controlled by a constant moving force control device, the electric rotation speed detection device 2 detects the Cutter rotation speed N
The detection signal of is sent to the function generator 3 to generate a function of the rotation speed, and the output signal of the function generator 3 and the output signal of the cutter feed speed detector 4 are compared by the servo amplifier 5. The output signal of the servo amplifier 5 controls the flow rate adjusting motor 7 for controlling the flow rate of the variable displacement pump 6 for feeding, and also adjusts the function generator 3. Accordingly, any rotation speed −
Since the feed rate curve can be programmed, the desired depth of cut can be automatically maintained depending on the rock type during the cut, ensuring maximum utilization of cutting power at all times and maximum depth of cut. It is possible to prevent the pick and machine from being damaged due to the depth being excessive for the rock quality, and the operator can perform the ideal cutting as described above without requiring special skill. It is particularly effective when cutting very hard rocks, i.e. when cutting hard rocks where automatic control tends to be unstable, and since all of the above controls are configured to be electrically controlled, the device is It has the advantage of being able to be manufactured to be small and lightweight, with fewer failures and high performance.

[Brief explanation of drawings]

Fig. 1 is a plan view showing an example of an excavator, Fig. 2 is a side view thereof, Fig. 3 is a schematic diagram showing an example of an automatic feed control device for an excavator, and Fig. 4 is an example of an automatic feed control circuit. Figure 5
The figure is a graph showing the relationship between torque and rotation speed when cutting with constant dynamic force, Figure 6 is a graph showing the relationship between depth of cut and rotation speed when cutting with constant dynamic force, and Figure 7 is a graph showing the relationship between cutting depth and rotation speed when cutting with constant dynamic force. FIG. 8 is a graph showing the relationship between feed rate and rotational speed in the case of constant cutting, and is a side view showing different types of cutting tools. In the figure, 1 is a cutter, 2 is an electric rotation speed detection device,
3 is a function generator, 4 and 4' are cutter feed speed detectors, 5 is a servo amplifier, 6 is a variable displacement pump for feeding, 7 is a servo motor for flow rate adjustment, 13 is a rotating frame,
16 is a hydraulic cylinder device for rotation, 19 is a cutter arm,
21 is a hydraulic cylinder device for elevating, 22 is an electric motor, 29 is a variable displacement pump for the cutter, 30 is a constant displacement hydraulic motor, 33 is a constant output control device, 35 to 37 are amplifiers, and 38 is a multiplier. , 39 are adders.

Claims (1)

[Claims] 1. Controlled by a constant motion control device. In an excavator that rotates a cutter 1 by a drive device and feeds the cutter 1 to cut rock, an electric rotation speed detection device 2 detects the rotation speed N of the cutter 1.
is connected to the input terminal of an adjustable function generator 3 that generates a function of the rotational speed N, and the output terminal of the cutter feed speed detector 4 and the output terminal of the function generator 3 are connected to the servo It is connected to the input terminal of an amplifier 5, and the output terminal of the servo amplifier 5 is connected to the input terminal of a flow rate adjustment servo motor 7 that controls the flow rate of a variable displacement pump 6 for feeding. Automatic feed control device for excavators.