JPH07158056A - Control device for soil improvement machine - Google Patents

Abstract

PURPOSE:To improve the soil to the best condition suitable for the properties thereof, regardless of the change of an excavation or drawing speed due to the properties, by calculating the number of revolutions of an agitation rod optimum for soil agitation at all times or at every unit time. CONSTITUTION:At an excavation and agitation process, an electric motor 7 is first started to rotate an agitation rod 8. Then, a drive section 4 is lowered, while the soil is being filled with chemicals 11 from the end of the rod 8, thereby improving the soil. When the soil is being excavated and agitated, a current excavation depth is always detected from the paid-out length or the like of a wire 5. Then, an excavation speed is calculated on the basis of a signal for the excavation depth so detected and furthermore, the optimum number of revolutions of the rod 8 is calculated, using the established formula. The result of the calculation is converted to a frequency signal and transmitted to the motor 7 and even to the rod 8. At the time of drawing the rod 8, the optimum number of revolutions is also calculated for the control thereof.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a control device for a ground improvement machine.

[0002]

2. Description of the Related Art Conventionally, as a ground improvement machine for making improvements such as hardening of the ground, there is one shown in FIG. 1 as an application example of the present invention. In this ground improvement machine, a drive unit 4 is suspended by a wire 5 along a guide rail 3 on a side surface of a leader mast 2 which is erected and supported on the work machine 1, and the wire 5 is mounted on a winch 6 mounted on the work machine 1. The drive unit 4 can be moved up and down by hoisting and lowering by means of an electric motor 7 in the drive unit 4, and a stirring rod 8 is connected to an output shaft that rotates via a speed reducer.

The electric motor 7 built in the driving unit 4 is driven to lower the driving unit 4 while rotating the stirring rod 8 at a predetermined rotation speed, and the excavation head 9 at the tip of the stirring rod 8 is driven.
While stirring the ground while excavating the ground, the ground improving agent (chemical solution 11) supplied through the stirring rod 8 is injected into the ground by the stirring blades 10, 10 ... Protruding around the stirring rod 8, The ground is of good geology.

In the above ground improvement, the stirring rod 8 is rotated at the number of rotations required to stir a unit depth in order to obtain good ground (the number of blade cutting in the case of a stirring rod with blades).
Stipulates to rotate.

[0005]

However, conventionally, the stirring rod 8 is lowered or raised at a constant speed while being rotationally driven at a predetermined constant number of rotations, but this operation mainly depends on the feeling of the operator. However, there was a problem of lack of reliability.

In view of the above, the present invention provides a control device in a ground improvement machine which can improve the ground to the best condition by the rotation speed of the stirring rod and the excavation speed or the withdrawal speed according to the property of the ground. With the goal.

[0007]

As a means for solving the problems of the above-mentioned prior art, the present invention is to connect a stirring rod having stirring blades to a drive unit which can be moved up and down along a leader mast, and to stir this stirring. In the ground improvement machine for excavating and stirring the ground by rotating and driving the rod by the electric motor in the drive unit, the frequency conversion device attached to the electric motor of the drive unit and the moving distance of the drive unit An excavation depth detecting device for detecting an excavation depth; and a computing device, wherein the computing device calculates the excavation speed or the withdrawal speed based on the excavation depth input from the excavation depth detecting device; The function to calculate the required number of rotations required at the present time by the speed or withdrawal speed and the number of rotations required to stir a preset constant depth, and And having a function of providing frequency conversion command to be converted the frequency conversion device.

[0008]

Operation: The electric motor is started to rotate the stirring rod, the chemical liquid is injected from the tip of the stirring rod, and the stirring operation is performed while lowering the drive unit. At this time, the excavation depth is constantly input from the excavation depth detection device to the arithmetic device, and the excavation speed is calculated. The required number of rotations of the stirring rod is calculated constantly or every unit time, and the result is converted into a frequency to give a frequency conversion command to the frequency conversion device.

Therefore, even if the excavation speed changes due to the nature of the ground or the like, the stirring rod must be adjusted to the required rotation speed corresponding to the current excavation speed each time, and the required rotation speed is always kept. become. This can be done in the same way when pulling out the stirring rod.

[0010]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below with reference to the embodiments shown in the drawings. The digging depth detection device 12 is configured by providing an encoder on the shaft of the sheave 13 around which the wire 5 that suspends the drive unit 4 is wound, and detects the digging depth by the unwinding amount of the wire 5. ing. However, other means may be used to detect the excavation depth.

The frequency converter 14 attached to the electric motor 7 and the arithmetic unit 15 are both mounted in appropriate places on the work machine 1.

As shown in FIG. 2, the circuit configuration including the arithmetic unit 15 and the frequency conversion unit 14 allows the arithmetic unit 15 to detect a detection signal from the excavation depth detecting unit 12, the number of revolutions of the stirring rod 8, and a current if necessary. In addition to the load current from the device 16, a driving operation signal is input depending on whether the rotation speed of the stirring rod 8 is manually switched or interlocked.

A frequency control signal from the arithmetic unit 15 is input to the frequency converter 14, and a frequency output signal is output from the frequency converter 14 and input to the arithmetic unit 15.

As an example of the above control contents, the minimum number of revolutions (hereinafter referred to as the number of blade cutting) required when the stirring rod 8 descends or rises in unit depth in order to perform good ground improvement is as follows. Determined.

T = Td + Tu (1) Td = M × Nd / Vd Tu = M × Nu / Vu Where T is the number of blade cutting (times / m) M is the number of stirring blades N is the required number of rotations at the current time to be adjusted (times / min) V is the speed of the stirring rod d is during excavation (descent) , U indicate the time of withdrawal.

Therefore, the required blades are obtained by agitating the rotating speed and the excavating speed (descent speed) at the time of excavation as Nd and Vd, respectively, and the rotating speed and the extracting speed (ascending speed) at the time of extraction as Nu and Vu, respectively. The number of times T of cutting can be realized.

On the other hand, the relationship between the rotation speed N of the stirring rod 8 and the frequency of the frequency converter 14 is N = R · 120f / P (4) where R The reduction ratio, P, the number of poles of the electric motor 7, and f, the frequency.

For the actual stirring work, if the blade cutting frequency T is 350 times / m and the number of stirring blades 10, 10, ... Provided on the stirring rod 8 is 10, 15 times at an excavation speed of 1 m / min during excavation. / Min, and when agitating at a drawing speed of 1 m / min and 20 times m / min at the time of drawing, T = 10 × (15/1 + 20/1) = 35 based on Equation 1 above.
It becomes 0 times / min, and it is possible to realize the number of blade cutting times of 350 times / min.

Therefore, when excavating and stirring, the electric motor 7 is used.
Is started to rotate the stirring rod 8, and the stirring operation is performed while injecting the chemical liquid 11 from the tip of the stirring rod 8 and lowering the drive unit 4. At this time, the excavation depth is constantly input from the excavation depth detection device 12 to the calculation device 15,
The excavation speed is calculated, and the required number of rotations of the stirring rod 8 is calculated constantly or at every unit time based on the above-mentioned mathematical formula 2, and the result is converted into a frequency and the frequency conversion device 14
To the frequency conversion command signal.

As a result, if the excavation speed changes due to the nature of the excavation ground, the stirring rod 8 is rotationally driven at the required number of revolutions that matches the excavation velocity at that time, and the number of revolutions always corresponds to that shown in FIG. As described above, it is possible to maintain a linear relationship between the excavation speed and the number of revolutions, and realize good ground improvement. This is also performed in the same manner when the stirring rod 8 is pulled out. However, it goes without saying that only one of the excavation and the extraction may be controlled.

[0021]

As described above, according to the present invention, since the stirring rod can be rotated at the required number of revolutions optimum for stirring the ground, the excavation speed or the withdrawal speed changes depending on the characteristics of the ground. However, the required number of rotations can be obtained accordingly, and efficient and favorable ground improvement can be performed. Further, since the frequency converter is used, an effect such as stepless control of the rotation speed can be obtained.

[Brief description of drawings]

FIG. 1 is a side view showing an example of a ground improvement machine to which the present invention is applied.

FIG. 2 is a circuit diagram of the same.

FIG. 3 is a graph showing the relationship between excavation speed and rotation speed.

[Explanation of symbols]

 2 Leader mast 4 Drive part 7 Electric motor 8 Stirring rod 9 Excavation head 10 Stirring blade 12 Excavation depth detection device 14 Frequency conversion device 15 Arithmetic device

Claims (1)

[Claims] Claim: What is claimed is: 1. A stir rod having stirrer blades is connected to a drive unit that can move up and down along a leader mast, and the stir rod is rotationally driven by an electric motor in the drive unit to excavate and stir the ground to improve the ground. In the ground improvement machine to be performed, a frequency conversion device attached to the electric motor of the drive unit, an excavation depth detection device for detecting an excavation depth from the moving distance of the drive unit, and an arithmetic unit, the arithmetic unit , A function of calculating an excavation speed or a withdrawal speed based on the excavation depth input from the excavation depth detection device, and a rotation speed required to stir the excavation speed or the withdrawal speed and a preset constant depth And a function of calculating the required rotation speed required by the above and converting the required rotation speed into a frequency and giving a frequency conversion command to the frequency conversion device. Controller in soil improvement machine that.