JPH04202996A - Excavation control device for earth drilling - Google Patents

Abstract

PURPOSE:To improve accuracy of an excavation hole by providing a detection means for a rotational frequency of a bucket and that for a push-in quantity of thrust, and also providing a control means controlling the rotational frequency to one time of the bucket and a push-in quantity from these detection means. CONSTITUTION:An excavation control device is composed of a rotational frequency detector 28 detecting a rotational frequency of a bucket 20, a detector 29 detecting a push-in quantity of a thrust cylinder 17, and a controller 30 controlling both the detectors 28 and 29. The rotational frequency detector 28 is faced with teeth of a gear 19, and one pulse per tooth is outputted to the controller 30. With the push-in quantity detector 29, a stroke of the thrust cylinder 17 is detected, and a stroke signal is outputted to the controller 30. Moreover the controller 30 is made a mechanism controlling a rotational frequency to one time of the bucket 20 and a push-in quantity of the thrust cylinder 17 from these pulse and stroke signals. This can excavate a highly accurate excavation hole.

Description

[Detailed Description of the Invention] A. Industrial Field of Application The present invention is directed to drilling holes for cast-in-place piles.・Regarding drilling control equipment for rills.

B. Prior Art The following types of earth drills have been known in the past as this type of earth drill.

That is, the earth drill is equipped with an earth drill body, and a Kellyba drive device that rotates and beats the Kelly bar is attached to the front frame of the earth drill body via a thrust cylinder, and a digging bucket is connected and fixed to the tip of the Kelly bar. ing. A side cutter for excavating the inner circumferential surface of the excavation hole is provided on the outer circumference of this bucket, and a bit is provided on the bottom surface. When the Kellyba drive device actively rotates the Kellyva drive device while applying thrust with the thrust cylinder, a hole can be excavated in the ground using the bit and side cutter formed on the bottom of the bucket.

C1 Problems to be Solved by the Invention However, the conventional earth drill drilling control device has the following problems.

■During excavation work, workers cannot see the excavation situation in the ground, so they use intuition and experience to estimate the excavation situation, such as by looking at the slack in the rope suspending Kerryba.
Adjusts the extension speed of the thrust cylinder. here,
If the extension speed of the thrust cylinder is too fast even though the ground is too soft, the pushing amount per bucket rotation will be larger than the height of the side cutter in the bucket pushing direction, and the side cutter will touch the inner circumferential surface of the drilled hole. There is a problem in that a spiral groove is formed, resulting in a so-called spiral digging.

On the other hand, if the operator is wary of this spiral digging in soft ground and slows down the extension speed of the thrust cylinder too much, there is a problem that the amount of push of the bucket will be reduced and the digging will take longer.

SUMMARY OF THE INVENTION An object of the present invention is to provide an earth drill excavation control device that can appropriately control the pushing amount per bucket rotation.

Means for Solving Problems D1 The present invention will be explained in conjunction with FIGS. 1 and 2 showing one embodiment of the present invention. The present invention is applied to an earth drill excavation control device that includes a drive means 120 that rotationally drives the bucket 20 and a thrust applying means 17 that applies thrust to the bucket 20.

Then, based on the detection signals of the rotation speed detection means 28 for detecting the rotation speed of the bucket 20, the push amount detection means 29 for detecting the push amount of the thrust applying means 17, and the amount detection means 28.29, the rotation speed of the bucket 20 is determined. The thrust applying means 17 calculates the pushing amount per rotation, compares this calculated value with a reference value determined according to the height of the sight cutter 22, and controls the thrust applying means 17 so that the pushing amount per rotation of the brush 98200 does not exceed the reference value. control means 30 for controlling the amount of pushing of the
This achieves the above objective.

Compare the pushing amount (LE) of the E0 action bucket 20 per rotation with a reference value (B) corresponding to the height of the sight cutter 22 in the bucket 20 pushing direction, and when LF≧B, determine the bucket pushing amount. In other words, the pushing speed by the thrust applying means 17 is reduced. Also, when LE<B,
Increase the pushing speed. Repeat these actions,
Excavation is performed by controlling the pushing amount of the bucket 20 per rotation so that it is always not larger than the height of the side cutter 22 in the bucket pushing direction, and not too small.

It should be noted that in the above-mentioned sections and section E, which describe the present invention in detail, figures of embodiments are used in order to make the present invention easier to understand, but the present invention is not limited to the embodiments.

F. Example One embodiment will be described below with reference to FIGS. 1 to 6.

In FIG. 3, reference numeral 11 denotes the main body of the earth drill. A telescopic jib 12 is erected on the main body 11, and a Kelly bar 13 is suspended from the upper end of the jib 12 with a rope 14. This rope 14 is a winch W mounted on the main body]1.
It is retracted and extended again to move the Kerry bar 13 up and down. A front frame 15 is provided on the front surface of the main body 11, and a housing 1 of a Kellyba drive device 16 is provided at the upper end of the front frame 15, as shown in FIG.
6a is suspended by a plurality of thrust cylinders 17.

That is, the head 17a of each thrust cylinder 17 is attached to the front frame 15, and the piston rod 17b is attached to the housing 16a.

As shown in FIG. 5, inside the housing 16a, a gear 18 and a gear 19 that mesh with each other are rotatably housed, and one gear 18 is connected to the rotating shaft of a hydraulic motor 120 installed on the top surface of the housing 16a. has been done. The boss portion 19a of the other gear 19 has a through hole 19 in the vertical direction.
b is formed, and the Kelly bar 13 is inserted therethrough. Through hole 1
A keyway 19c is formed in the inner circumferential surface of 9b. A sliding key (not shown) extending vertically is projectingly provided on the outer peripheral surface of the kelly bar 13, and this sliding key is slidably fitted into the keyway 19c. Therefore, the Kelly bar 13 can slightly reduce the transmission of rotational force to the Kelly bar drive device 16 while raising and lowering its engagement position.

Again in FIG. 3, reference numeral 20 denotes a substantially cylindrical bucket connected to the lower end of the Kelly bar 13, and as shown in FIG. Excavation is carried out, and the excavated soil is sent into the bucket 20.

A plurality of sight cutters 22 are protruded from the outer periphery of the bucket 20, and these side cutters 22 excavate the soil at the inner periphery of the excavated hole 21. The scraped soil passes through the X opening (not shown) formed on the outer circumferential surface of the bucket 20.
sent inside.

FIG. 1 shows a hydraulic control circuit for a Kellyba drive device and a thrust cylinder. Pressure oil discharged from a variable displacement hydraulic pump 122 is guided to the above-mentioned hydraulic motor 120 via an electromagnetic switching valve 23. When the switching valve 23 is switched to the A position, the hydraulic motor 20 rotates in the normal direction, and the gear 18.1
When the selector valve 23 is switched to the opening position, the hydraulic motor 120 rotates in the reverse direction and drives the Kelly lever 13 in the reverse direction via gears 18 and 19.

Pressure oil discharged from the constant displacement hydraulic pump 24 is guided to the thrust cylinder 17 via an electromagnetic switching valve 25, and when the switching valve 25 is in the A position, the thrust cylinder 1
7 expands. In other words, the pressure oil flows through the electromagnetic proportional flow control valve 2.
The oil in the rod side chamber is throttled to a predetermined flow rate by the throttle 26a of No. 6 and supplied to the head side chamber of the thrust cylinder 17, and the oil in the rod side chamber returns to the tank from the switching valve 25. Further, when the switching valve 25 is in the opening position, the thrust cylinder 17 contracts. That is, pressure oil is supplied to the rod side chamber of the thrust cylinder 17, and oil in the head side chamber is returned to the tank from the check valve 26b of the electromagnetic proportional flow control valve 26 and the switching valve 25.

27 is a pressure detector provided in the normal rotation side (excavation side) conduit of the switching valve 23 and the hydraulic motor 120, and this pressure detector 27 detects the excavation motion pressure of the hydraulic motor 120, and When the pressure exceeds a predetermined value, the control device 30 (described later)
Outputs a detection signal to

28 is a rotation speed detector provided facing the teeth of the gear 19, and this rotation speed detector 28 controls one pulse as a detection signal every time it faces the teeth of the gear 19, that is, for each - tooth. Output to device 30.

29 is a stroke detector provided near the piston rod 17b of the thrust cylinder 17.

This stroke detector 29 detects the stroke of the thrust cylinder 17 and outputs a detection signal corresponding to this stroke to the control device 30.

Reference numeral 30 denotes a control device consisting of a CPU, RAM, ROM, and other peripheral devices, and as shown in detail in FIG. 2, this control device 30 includes arithmetic units 31. Differentiator 32, multiplier 33.
Comparator 34. It has a reference value setter 35 and an integrator 36.

Based on the pulse signal output from the rotation speed detector 28, the calculator 31 multiplies the period T1 of one pulse by the number n of pulses corresponding to the number of teeth of the gear 19, and calculates the time T required for one rotation of the bucket 20. (=T1×n) is calculated. The differentiator 32 receives the detection signal L e from the stroke detector 29
The zero multiplier 33 calculates the extension speed Lev of the piston rod 17b by differentiating the time T calculated by the calculator 31.
By multiplying by the speed Lev calculated by the differentiator 31, the amount of extension LE (=LeνXT) of the piston rod 17b per rotation of the bucket 20 is calculated. This extension amount LE
is taken as one input of the comparator 34.

A reference value B corresponding to the vertical height of the side cutter 22 is set in the reference value setter 35, and this reference value B is used as a reference input to the comparator 34.

A comparator 34 compares the extension amount LE calculated by the multiplier 33 with a reference value B, and when LE≧B, a negative signal is sent to LE.
When <B, a positive signal is output to the integrator 36 at the subsequent stage.

This integrator 36 is constructed as follows. When a detection signal is output from the pressure detector 27 during excavation, the integrator 3
6 integrates the signal from comparator 34. During non-excavation when no detection signal is output, the integrator 36 has an initial value (positive predetermined value).
will be reset to When the integrator 36 is reset to the initial value, the electromagnetic proportional flow rate regulating valve 26 is fully opened.

Next, the operation will be explained.

Prior to work, switch the switching valve 25 to the opening position to contract the thrust cylinder 17. Switch the switching valve 23 to the A position to supply the pressure oil discharged from the hydraulic pump 122 to the hydraulic motor 120, and the gear 18 .19 and Kerryba 1
3, the bucket 20 is driven in normal rotation. At the same time, the switching valve 25 is switched to the A position and the thrust cylinder 17
and further extend the rope 14 to the thrust cylinder 17.
Pay out according to the extension of the. bit 20 of bucket 20
a excavates the ground using the weight of the Kelly bar 13 and the bucket 20 and the thrust of the thrust cylinder 17, and the side cutter 22 excavates the side of the hole to enlarge the diameter of the hole formed by the bit 20a, thereby making the hole 2
Note that the thrust by the thrust cylinder 17 is transmitted by the sliding resistance (when torque is generated) between the Kelly bar 13 and the gear 19 of the Kelly bar drive device 16.

During excavation, the pressure in the pressure oil supply side pipe becomes equal to or higher than a predetermined value, and the integrator 36 is in a state where it can integrate the signal from the comparator 34 based on the detection signal output by the pressure detector 27. The rotation speed detector 28 emits a pulse signal synchronized with the rotation speed of the gear 19, and the calculator 31 calculates the time T required for one rotation of the bucket based on this pulse signal.

On the other hand, the amount of extension of the piston rod 17b is detected by a stroke detector 29, and the detection signal Le is differentiated by a differentiator 32 to calculate the extension speed Lev of the piston rod 17b. The multiplier 33 multiplies the time T required for one rotation of the bucket 20 by this speed Lev, and calculates the extension amount LE of the piston rod 17b per one rotation of the bucket 20.
=LevXT) is calculated. The comparator 34 calculates this amount of extension L.
E and the sight cutter 22 output from the reference value setting device 35
A comparison is made with a reference value B corresponding to the vertical height of .

Here, when LE≧B, the comparator 34 outputs a negative signal to the integrator 36. Since a predetermined positive value is set as an initial value in the integrator 36, the integrated value becomes smaller each time the negative signal from the comparison @34 is integrated. The throttle opening degree of the electromagnetic proportional flow regulating valve 26 becomes smaller as the applied signal becomes smaller. Therefore, under the condition of LE≧B, the throttle 26a of the electromagnetic proportional flow Ik regulating valve 26 is gradually narrowed, and the piston rod 1
The extension speed Lev of 7b becomes slow, and the extension amount LE per rotation of the Kelly bar decreases. When this extension amount LE decreases further and becomes LE<H, the comparator 34 applies a positive signal to the integrator 36. As a result, the integral value of the integrator 36 gradually increases, and the electromagnetic proportional flow rate is 1! Throttle 26 of III valve 26
The aperture opening degree of a gradually increases, and the extension speed of the piston rod 17a becomes faster.

When the piston rod 17b of the thrust cylinder 17 protrudes to the stroke end by repeating this operation, the switching valve 23 is switched to the neutral position and the hydraulic motor 120
Then, the switching valve 25 is switched to the open position and the thrust cylinder 17 is contracted. At this time, Kellyba 1
Since no torque is generated in 3, only the Kellyba drive device 16 is pulled up by the screws 1 to 17b.

Furthermore, since the pressure in the normal rotation side conduit of the hydraulic motor 120 is below a predetermined value, the pressure detector 27 does not output a detection signal, so the integrator 36 is reset to the initial value, and the electromagnetic proportional flow rate adjustment valve 26 is The aperture 26a is fully opened. Therefore, the contraction speed of the piston rod 17a of the thrust cylinder 17 does not slow down, and the working efficiency does not decrease.

In this way, when LE≧B, the electromagnetic proportional flow rate regulating valve 26
throttle 26a to reduce the amount of extension of the thrust cylinder 17 per rotation of the Kelly bar until LE<H, and LE<H.
At the time of B, since the aperture opening of the aperture 26a is increased and the extension amount LE is increased, 1 of the bucket 20 is
Excavation can be performed at a pushing amount per rotation always close to the height of the side cutter 22 in the bucket pushing direction.

Therefore, especially when excavating on war ground, spiral digging is prevented and highly accurate excavation can be performed. Furthermore, by appropriately determining the reference value B, excavation can be performed with the pushing amount of the bucket 20 always close to the spiral excavation limit value, so that excavation can be performed in a short time without reducing the excavation speed.

Note that the point of the present invention is to match the bucket rotation speed and pushing speed so that a spiral groove is not formed by the side cutter. It may be modified as follows.

(1) The bucket rotation drive device may be an electric type.

(2) The bucket pushing force is not based on a hydraulic cylinder, but may be applied using a hydraulic motor or an electric type.

(3) Pushing speed control is not limited to the flow rate control method using a throttle, but may also be performed by making the hydraulic pump 24 variable or by metering control of the switching valve 25.

In some cases, the input rotation speed of the hydraulic pump 24 may be controlled.

(4) The detection calculation of the bucket rotation speed and the detection calculation of the pushing speed are not limited to the method of the embodiment.

Detects the rotation speed of the hydraulic motor 120,
3 may be detected.

In the configuration of the above embodiment, the hydraulic pump 120 controls the drive means 120, the thrust cylinder 17 controls the thrust applying means, the rotation speed detector 28 controls the rotation speed detection means, and the stroke detector 29 controls the pushing amount detection means. The devices 30 each constitute a control means.

G1 Effects of the Invention As described above, according to the present invention, the amount of pushing per rotation of the bucket is compared with a reference value determined according to the height of the side cutter, and the amount of pushing is prevented from exceeding the reference value. Since the pushing amount of the thrust applying means is controlled, highly accurate excavation without spiral grooves can be performed without reducing excavation efficiency.

[Brief explanation of the drawing]

1 to 6 show an embodiment of the excavation control device of Astoril according to the present invention, FIG. 1 is a hydraulic control circuit diagram thereof, FIG. 2 is a detailed block diagram of its calculation device, Fig. 3 is an overall view of Astoril, Fig. 4 is a sectional view of the main parts of the Kellyva Drive device, Fig. 5 is a sectional view taken along line V-V in Fig. 4,
FIG. 6 is a diagram showing the bucket and the excavation state. 17: Thrust cylinder 2o: Bucket 22: Side force vine 28: Rotation speed detector 29: Push amount detector 30: Control device] 2o: Hydraulic motor

Claims (1)

[Scope of Claim] An excavation control device for an earth drill comprising a bucket with a side cutter, a drive means for rotationally driving the bucket, and a thrust applying means for applying a thrust to the bucket, comprising: a rotation speed of the bucket; a rotational speed detecting means for detecting the pushing amount of the thrust applying means; a pushing amount detecting means for detecting the pushing amount of the thrust applying means; and a pushing amount of the bucket per rotation based on the detection signals of both the detecting means; control means for comparing the calculated value with a reference value determined according to the height of the side cutter and controlling the pushing amount of the thrust applying means so that the pushing amount per one rotation of the bucket does not exceed the reference value. An earth drill drilling control device characterized by: