JP2895677B2 - Ground hardness judgment device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an apparatus for judging the hardness of a ground used in a machine for foundation work such as an earth auger or an earth drill.

[0002]

2. Description of the Related Art When performing a foundation work on a building or the like, a machine for foundation work such as an earth auger that excavates a predetermined depth from the ground is known. When performing the construction using an earth auger, usually, in order to know the hardness of the ground, drilling is performed in advance and the position, that is, the depth of the hard ground is investigated. The actual construction site determines the target excavation depth based on this result. By the way, since boring is performed by sampling several specific places, it often differs from the geological condition of the actual excavation place. For this reason, conventionally, it has been empirically determined that the driver has reached the hard ground from the load current of the electric motor driving the auger unit and the descent speed of the auger unit. That is, when the auger rotation speed is constant, the motor load current, the auger descent speed,
With the hardness of the ground, if the descent speed is constant, the load current increases as the ground becomes harder, and the load current increases as the descent speed increases even with the same hardness of the ground. By monitoring the value of the motor load current, the hardness of the ground can be grasped. In addition, as a device that uses the above relationship to quantitatively display the hardness of the ground, a device that calculates the ground hardness index from the motor load current and the auger descent speed and displays the result is displayed. It has been proposed (JP-A-63-67319).

[0003]

The conventional judging method is based on the premise that a motor having a constant rotation speed is used for the driving device. For this reason, in a drive device whose rotational speed fluctuates, for example, a drive device using a hydraulic motor, accurate load fluctuation cannot be grasped only by detecting the drive torque of the hydraulic motor instead of the motor load current, and the hardness of the ground Can not judge. Therefore, it has been desired to develop a device that can determine the hardness of the ground by the same method as a drive device having a constant rotation speed even when such a rotation speed variable drive device is used. An object of the present invention is to provide a ground hardness determination device that can accurately determine the hardness of the ground even when the rotation speed of the driving device fluctuates.

[0004]

According to a first aspect of the present invention, there is provided a judging device for detecting a digging torque of a driving device, a digging torque detecting device for detecting a digging torque of a driving device, and a rotating device for detecting a rotation speed of the driving device. A load current equivalent value for calculating a load current equivalent value corresponding to a motor load current when it is assumed that a motor having a constant rotation speed is used as a drive device, based on the number detection means 11 and the detected excavation torque and rotation speed. By providing the value calculation means 13 and the load current equivalent value display means 15, 16, 17 for displaying the calculation result, the above-mentioned problem is solved. In addition, in association with FIG. 5, in the determination device of claim 2, an excavation torque detection unit 10 that detects an excavation torque of the drive device, a rotation speed detection unit 11 that detects a rotation speed of the drive device, A descent speed detecting means 20 for detecting a descent speed of the member, a hardness index calculating means 22 for calculating a ground hardness index based on the detected excavation torque, rotation speed and descent speed, and the calculation result is displayed. Hardness index display means 24, 25, 26.

[0005]

According to the first aspect of the present invention, the excavation torque detected by the excavation torque detection means and the rotation speed detected by the rotation speed detection means are input to the load current equivalent value calculation means, and the load current is calculated. An equivalent value is calculated. The calculation result is displayed on the load current equivalent value display means 15 to 17. Since the displayed load current equivalent value is equivalent to the load current value when a motor having a constant rotation speed is used, by comparing this value with the descent speed of the excavated member, the same as in the case of the electric motor drive device The hardness of the ground. According to the determination device of the second aspect, the excavation torque detected by the excavation torque detection means 10, the rotation speed detected by the rotation speed detection means 11, and the descent speed detected by the descent speed detection means 20 are represented by a hardness index. The data is input to the calculating means 22, and the hardness index of the ground is calculated. The calculation result is displayed on the hardness index display means 24-26.

In the section of the means for solving the above-mentioned problems and the operation which explain the constitution of the present invention, the drawings of the embodiments are used to make the present invention easy to understand. However, the present invention is not limited to this.

[0007]

Embodiments of the present invention will be described below with reference to the drawings. First Embodiment FIG. 2 shows an example of a machine for foundation work provided with an earth auger to which the present invention is applied. The machine 1 for foundation work
An auger unit 2 and an auger unit elevating chain 3 that suspends the auger unit 2 are provided. The auger unit 2 includes a digging mechanism 4 and an auger screw 5.
And a drilling head 6 attached to the tip of the screw 5. The excavation mechanism 4 includes a hydraulically driven auger motor (not shown), transmits the rotation of the auger motor to the auger screw 5, and rotates the auger screw 5 and the excavation head 6 at a predetermined rotation speed.

FIG. 1 shows a block diagram of a first embodiment of the present invention. The excavation torque detector 10 detects the excavation torque from the inlet pressure of the auger motor, and the rotation speed detector 11 detects the rotation speed of the auger screw. The detection results of the excavation torque detector 10 and the rotation speed detector 11 are applied to the A / D conversion unit 12, respectively.
The A / D conversion unit 12 includes a multiplexer and an A / D converter (not shown), and digitizes the excavation torque and rotation speed of the auger motor. The microcomputer unit 13 calculates and outputs a load current equivalent value I _K based on the excavation torque and the rotation speed digitized by the A / D conversion unit 12 as described later. Here, the load current equivalent value I _K is a value obtained by converting the excavation torque of the excavation mechanism 4 into a motor load current when excavating the same ground with a motor type excavation mechanism having a constant rotation speed. Will be described later. Although not shown, the microcomputer unit 13 includes a microprocessor unit MPU for performing calculations and controls, and a read-only memory ROM storing a processing procedure program for the microprocessor unit MPU.
And a random access memory RAM for storing input data and operation results.

The D / A converter 14 receives an output of the operation result of the load current equivalent value I _K from the microcomputer unit 13. The D / A converter 14 outputs the operation result output from the microcomputer unit 13. Is converted to an analog value. A meter 15 and a recorder 16 are connected to the D / A converter 14, and the meter 1
5 is D / A of the load current equivalent value I _K by the D / A converter 14.
The A conversion result is displayed, and the recorder 16 displays the load current equivalent value I.
The D / A conversion result of _K is recorded. Further, a printer 17 is connected to an output port of the microcomputer unit 13, and the printer 17 records an operation result of the microcomputer unit 13. In this embodiment, although not shown,
An indicator such as a meter for displaying the descending speed of the auger unit 2 is provided near the meter 15 or the like.

[0010] Here, for the understanding of the operation of the determination apparatus according to the present embodiment, the drilling torque reference to excavation mechanism 4 to FIG. 3, the speed and load current equivalent value I _K, the constant number of revolutions The relationship with the motor load current in the motor type excavation mechanism will be described. FIG. 3 is a diagram illustrating a state in which the auger unit 2 is lowered at a predetermined speed, and the auger motor is operated to rotate the auger screw 5 and the excavating head 6 to excavate the ground. In FIG. 3, the hardness index (mainly the ground shear stress) representing the hardness of the ground is “H”,
Assuming that the excavation cut width is “t” and the excavation width is “b”, the excavation force F is expressed as F∝H · t · b (1). Since the excavation cut width t corresponds to the excavation amount per auger screw rotation, the auger unit 2
If the descent speed of the auger screw 5 is N and the rotation speed of the auger screw 5 is N, the expression (1) is as follows: F∝H ・ v ・ b / N (2) The relationship between the excavation torque T and the excavation force F is expressed as T∝F (3), where the excavation torque T represents excavation energy.

Here, when the excavation energy e of the motor-driven excavating mechanism with a constant rotation speed is represented by the load current I of the electric motor, e = (I−I ₀ ) · E · Δt (4) Here, I ₀ is an auger no-load current, that is, a current when no excavation is performed, E is a load voltage of the electric motor, and Δt is a unit time. Since b, E, and Δt are constant and N is also constant in the motor-driven excavating mechanism, the hardness index H is expressed as H∝ (I−I ₀ ) / from formulas (2), (3), and (4). v is expressed as (5). As is apparent from this equation, in a digging mechanism with a constant rotation speed, a change in ground hardness can be grasped by monitoring only changes in the motor load current and the auger descent speed.

On the other hand, in the hydraulic motor type excavating mechanism 4 in which the auger rotation speed changes, the excavation torque e is calculated based on the excavation torque T.
And e = (T−T ₀ ) / Δt (6) T ₀ is the auger no-load torque, that is, the torque when no excavation is performed. Here, since b and Δt are constant, the hardness index H is obtained from the equations (2), (3) and (6).
Is expressed as H∝ (T−T ₀ ) · N / v (7).

From equations (5) and (7), the following equation is obtained between the excavating torque T and the rotational speed N of the hydraulic motor type excavating mechanism 4 and the load current I of the electric motor type excavating mechanism: (I−I ₀ ) = k · (T−T ₀ ) · N (8) is established. Here, k is a proportional constant, and is determined according to the motor characteristics of the hydraulic motor type excavating mechanism 4 and the electric motor characteristics of the electric motor type excavating mechanism to be compared. By obtaining the proportional constant k in advance, the load current equivalent value I _K can be calculated according to the following equation (9). I _K = k · (T−T ₀ ) · N (9)

Next, the operation of the judgment apparatus of the first embodiment will be described.
The processing procedure in the microcomputer unit 13 will be described with reference to FIG. In FIG. 4, in step S1, the load current equivalent value I _K is first cleared and the initial value is set to “0”.
To Next, in step S2, the excavation torque T is input, and in step S3, the excavation torque T is compared with the torque T ₀ when no load is applied. As a result of the comparison, when the excavation torque T is larger than the no-load torque T ₀ , the process proceeds to step S4. When the excavation torque T is equal to or less than the no-load torque T ₀ , excavation is not performed, and the process proceeds to step S6 to keep the load current equivalent value I _K as it is. Step S4
Then, the rotation speed N of the auger is input, and in the next step S5, the load current equivalent value I _K is calculated from the excavation torque T and the rotation speed N according to the above-mentioned equation (9). In step S6, the calculated load current equivalent value _IK is output.

[0015] As described above, to measure the load current equivalent value I _K repeats the processes of steps S1 to S6. The calculation result of the load current equivalent value I _K is recorded in the printer 17 and is also converted into an analog signal by the D / A converter 14 and recorded in the meter 15 and the recorder 16.

According to this embodiment, the load current equivalent value I _K displayed on the meter 15 or the like corresponds to the motor load current when the same ground is excavated by the motor type excavation mechanism having a constant rotation speed. By monitoring the display value of the load current equivalent value I _K and the descent speed v of the auger unit 2, it is possible to determine the hardness of the ground in the same manner as in a conventional constant-rotation-type excavation mechanism. In addition, since the rotation speed N of the auger unit 2 is incorporated in the calculation formula of the load current equivalent value I _K , the variation in the auger rotation speed does not become an error factor in determining the hardness of the ground, and the hardness of the ground Can always be accurately grasped.

-Second Embodiment- Next, a second embodiment of the apparatus for determining the hardness of the ground according to the present invention will be described with reference to FIGS. The same parts as those in the first embodiment are denoted by the same reference numerals, and description thereof will be omitted.
In the second embodiment, a descent speed detector 20 for detecting the descent speed of the auger unit 2 is provided, and the detection result of the descent speed detector 20 is the detection result of the excavation torque detector 10 and the rotation speed detector 11. A / D conversion unit 2
It is added to 1 and digitized. The microcomputer unit 22 calculates and outputs a hardness index H based on the excavation torque, rotation speed, and descent speed digitized by the A / D conversion unit 21. That is, in the first embodiment, the microcomputer unit 13 calculates the load current equivalent value I _K from the excavation torque and the rotation speed, whereas in the second embodiment, the microcomputer unit 22 is described above ( The hardness index H itself is calculated according to the equation (7).

The operation result of the microcomputer unit 22 is output to a D / A converter 23, and the D / A converter 23
Converts the calculation result of the hardness index H into an analog value. D /
The A conversion result is displayed on the meter 24 and recorded on the recorder 25. The calculation result of the microcomputer unit 22 is also output to the printer 26, and the printer 26 records the calculation result.

Next, the operation of the apparatus for determining the hardness of the ground according to the second embodiment will be described with reference to FIG. In FIG. 6, in step S11, first, the hardness index H is cleared, and the initial value of the hardness index H is set to “0”. Then enter the drilling torque T in step S12, it compares the torque T ₀ during excavation torque T and unloaded in step S13. As a result of the comparison, when the excavating torque T is larger than the no-load torque T ₀ , the process proceeds to step S1 to further determine whether the descent speed v is larger than the minimum limit speed vmin.
Proceed to 4. When the excavation torque T is equal to or less than the no-load torque T ₀ , excavation is not performed, and the process proceeds to step S18 to keep the hardness index H as it is.

In step S14, the descending speed v of the auger unit 2 is input, and in step S15, the descending speed v is compared with the minimum limit speed vmin. As a result of the comparison, when the descent speed v is larger than the minimum limit speed vmin,
Since the excavation has been performed, the process proceeds to step S16 to measure the hardness index H at this time. When the descent speed v is equal to or lower than the minimum limit speed vmin, no excavation is performed, and the process proceeds to step S18 to keep the hardness index H as it is. In step S16, the rotational speed N is input to calculate the hardness index H, and in the next step S17, the hardness index H
Is calculated from the excavation torque T, the rotation speed N, and the descent speed v based on the above equation (7). In step S18, when the excavation is not performed, the current hardness index H is output as it is, and when the excavation is performed, step S18 is performed.
The hardness index H calculated at 17 is replaced with a new hardness index H
Output as

As described above, the processing of steps S11 to S18 is repeated to measure the hardness index H. The calculation result of the hardness index H can be recorded on the printer 26,
The analog signal is converted by the / A converter 23 and recorded in the meter 24 and the recorder 25.

According to this embodiment, the operator of the foundation work machine 1 can judge the hardness of the ground currently being excavated based on the hardness index H displayed on the meter 24 or the recorder 25. Therefore, it is possible to immediately and accurately grasp the geological state of the place where the excavation is actually being performed. Moreover, since the hardness index H itself is displayed, the experience of the conventional method of judging the hardness of the ground from the two display values of the motor load current and the descent speed is not required, and it is easy even for a skilled worker. The hardness of the ground can be determined. further,
Since the rotational speed N is incorporated in the arithmetic expression of the hardness index H,
An error does not occur in the hardness index H due to a change in the rotation speed.

Third Embodiment Next, with reference to FIGS. 7 and 8, a description will be given of a third embodiment of the apparatus for determining the hardness of the ground according to the present invention. The parts common to the first and second embodiments are denoted by the same reference numerals, and the description is omitted. In the third embodiment, the hardness index H and the excavation depth D output from the microcomputer unit 22 are analog-converted by the subsequent D / A converters 23 and 30, and the hardness index H and the excavation depth D are converted. The data is added to the XY recorder 31. Then, the XY recorder 31 graphs and records the hardness index H with respect to the excavation depth D as shown in FIG. In addition, the excavation depth D is the descent speed detector 2
It is easily obtained by integrating the data of 0.

As described above, in the third embodiment, the hardness index H calculated by the microcomputer unit 22
Is graphed together with the digging depth D and recorded on the XY recorder 31, so that the driver can more accurately grasp the hardness index H at a predetermined digging depth while digging the ground. Becomes This enables reliable and clear construction management. The recording example shown in FIG. 8 is consistent with the boring result that there is a slightly hard layer at about 2 m from the ground surface and a hard support layer at about 8 m.

In the above embodiment, the excavating head 6 is for excavating members, the excavating torque detector 10 is for excavating torque detecting means,
The rotation speed detector 11 constitutes rotation speed detection means, and the descent speed detector 20 constitutes descent speed detection means. Further, the microcomputer unit 13 in the first embodiment constitutes a load current equivalent value calculation means, and the meter 15, the recorder 16 and the printer 17 constitute a load current equivalent value display means. The microcomputer unit 22 in the second and third embodiments constitutes a hardness index calculating means, and the meter 24, the recorder 25 and the printer 26, or the XY recorder 31 constitutes a hardness index display means. The present invention can be used for a drilling device such as an earth drill other than the earth auger.

[0026]

As described above in detail, according to the determination apparatus of the first aspect, the load current equivalent value calculating means can be used.
A load current equivalent value corresponding to the motor load current when a motor having a constant rotation speed is used as the drive device is calculated, and the calculation result is displayed on the load current equivalent value display means, so that the motor load current and the auger descent speed are displayed. Thus, the ground hardness can be determined in the same manner as the conventional method of determining the hardness of the ground. In addition, since the rotation speed of the driving device is taken into account when calculating the load current equivalent value, the hardness of the ground can be accurately determined even if the rotation speed fluctuates. By this, it is possible to prevent poor construction such that the excavation depth does not reach the hard support layer, and at the same time, when the hard support layer is located at a position shallower than the previous drilling result,
Since it is possible to determine whether to excavate, the efficiency of construction can be improved. According to the determination device of claim 2, the hardness of the ground that is currently being excavated is automatically measured by the hardness index calculating means and displayed on the hardness index display means. The hardness of the ground can be easily determined during excavation.

[Brief description of the drawings]

FIG. 1 is a block diagram of a first embodiment of the present invention.

FIG. 2 is a schematic side view of a machine for foundation work.

FIG. 3 is a diagram for explaining excavation force.

FIG. 4 is a flowchart illustrating a processing procedure in a load current equivalent value calculation unit according to the first embodiment;

FIG. 5 is a block diagram of a second embodiment of the present invention.

FIG. 6 is a flowchart showing a processing procedure in a hardness index calculating means of the second embodiment.

FIG. 7 is a block diagram of a third embodiment of the present invention.

FIG. 8 is a view showing a measurement result recorded by the XY recorder of the third embodiment.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 foundation work machine 2 auger unit 4 excavating mechanism 5 auger screw 6 excavating head 10 excavating torque detector 11 rotation speed detector 13,22 microcomputer unit 15,24 meter 16,25 recorder 17,26 printer 20 descending speed detector 31 XY recorder

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-63-142114 (JP, A) JP-A-62-78310 (JP, A) JP-A-1-207513 (JP, A) (58) Field (Int.Cl. ⁶ , DB name) E02D 1/02 G01N 3/40

Claims (2)

(57) [Claims] 1. An apparatus for determining the hardness of a ground used in an excavator for drilling a hole in the ground with an excavating member rotationally driven by a drive, comprising: an excavation torque detector for detecting an excavation torque of the drive; Rotation speed detection means for detecting the rotation speed of the device; and a load corresponding to a motor load current when it is assumed that a motor having a constant rotation speed is used for the drive device based on the detected excavation torque and rotation speed. A ground hardness judging device comprising: a load current equivalent value calculating means for calculating a current equivalent value; and a load current equivalent value display means for displaying the calculation result. 2. An apparatus for determining the hardness of a ground used in an excavator for drilling a hole in the ground with an excavating member rotationally driven by a drive, comprising: an excavation torque detector for detecting an excavation torque of the drive; Rotation speed detection means for detecting the rotation speed of the device, descent speed detection means for detecting the descent speed of the excavation member, based on the detected excavation torque, rotation speed and descent speed, the hardness index of the ground An apparatus for determining a ground hardness, comprising: a hardness index calculating means for calculating; and a hardness index displaying means for displaying the calculation result.