JP2001214686A - Excavation torque controller - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain an excavation torque controller dissolving the complexity of a switching-over and, at the same time, preventing the excavation torque controller from damage or the like caused by forgetting the switching-over. SOLUTION: When the present depth L is shallower than the torque switching depth Ls, it is decided that the excavation is carried out by a casing tube 40 (step 225), and the setting torque TS makes the maximum toque Tk of the casing tube 40 (step 235). When the depth L is deeper than the switching depth Ls, it is decided that the excavation is carried out by an excavator 36 (step 225), and the setting torque TS makes the maximum toque TB of the excavator 36 (step 245). When the setting torque is in excess of the maximum torques Tk and TB (step 230 and 240), the setting torque makes the maximum torques Tk and TB (step 235 and 245).

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a drilling torque control for controlling the output torque of a rotary drive mechanism for rotating a casing tube and rotating a kelly bar attached to a tip thereof with a drilling tool inserted into the casing tube. Related to the device.

[0002]

2. Description of the Related Art Conventionally, the output torque of a rotary drive mechanism for rotationally driving an excavator has been controlled to prevent the excavator from being damaged. For example, as disclosed in Japanese Patent Application Laid-Open No. 10-280409, when a hydraulic motor whose displacement is variable according to the pilot pressure introduced is used, the output pressure is controlled by controlling the pilot pressure by a control device. ing.

Further, the control device controls the output torque so as not to exceed a set torque set by a setting switch, regulates an output torque of the hydraulic motor, and prevents breakage of a drilling tool. .

[0004]

However, one rotary drive mechanism rotates a casing tube having a cutting bit attached to the tip and a kelly bar attached to the tip with a drilling tool inserted into the casing tube. It may rotate and excavate. In such a case, the setting switch was adjusted each time according to the time of excavation with the casing tube and the time of excavation with the drilling tool, so the setting was cumbersome, and the setting was forgotten. Or incorrect settings may lead to damage or the like.

An object of the present invention is to provide an excavating torque control device which eliminates the complexity of switching and prevents breakage due to forgetting to switch.

[0006]

In order to achieve the above object, the present invention takes the following means to solve the problem. That is, the output torque of the rotary drive mechanism that rotates the casing tube with the drill bit attached to the tip and rotates the kelly bar attached to the tip with the drilling tool inserted into the casing tube is regulated according to the set torque. In the excavating torque control device, a depth measuring unit that measures the depth of the excavating tool, and the set torque is set to a maximum torque corresponding to the casing tube or a maximum corresponding to the excavating tool according to the detected depth. An excavating torque control device is provided with switching control means for setting a torque.

[0007] The depth measuring means may measure the depth based on the amount of movement of a wire suspending the keriba. Furthermore, when the set torque is larger than the maximum torque switched by the switching control means, a limiter that sets the maximum torque to the set torque may be provided. The digging implement may be a digging bucket.

[0008]

Embodiments of the present invention will be described below in detail with reference to the drawings. As shown in FIG. 1, reference numeral 1 denotes a self-propelled excavation machine, on which a leader 2 is provided upright, and a set of rails 4 (only one is shown) is provided along the longitudinal direction of the leader 2. Is laid).

A moving table 6 is slidably engaged with the rail 4, and a rack (not shown) is provided between the pair of rails 4 in parallel with the rail 4 in the reader 2. A pinion gear (not shown) rotated by a motor 8 provided on the moving table 6 is meshed with the rack, and the moving table 6 can be moved up and down along the rail 4 by the rotation of the motor 8. It is configured.

A rotary drive mechanism 10 is mounted on the moving table 6, and as shown in FIG. 2, the rotary drive mechanism 10 includes a hydraulic motor 12, and a small gear 14 attached to the hydraulic motor 12 has a The large gear 16 is meshed. Large gear 16
A large gear 22 that rotates integrally with a transmission shaft 20 that is rotatably supported is meshed with the small gear 18 that rotates integrally with the small gear 18.

The transmission shaft 20 has a sliding hole 24 in its axial direction.
Is formed, and a kelly bar 26 is slidably inserted into the sliding hole 24. For example, when the cross-sectional shape of the kelly bar 26 is square, the sliding hole 24 is also a square hole corresponding thereto, or when the kelly bar 26 is of a spline shape, the sliding hole 24 is corresponding thereto. Hole shape,
The rotation of the transmission shaft 20 is configured to be transmitted to the kelly bar 26.

A wire 28 is fastened to the upper end of the kelly bar 26. The wire 28 is connected to a pair of sheaves 3 provided at the upper end of the leader 2 from the main winch 34 of the excavator 1.
It has been withdrawn through 0,32. A drilling tool 36 is attached to a lower end of the kelever 26. Drilling tool 36
Include, for example, a drilling bucket and an auger drill.

At the lower end of the transmission shaft 20, a joint member 38 is fixed. The joint member 38 is formed in a hollow shape so that the kelly bar 26 can pass therethrough. In addition, the joint member 38 has a lower end formed on the casing tube 4.
The casing tube 40 has a plurality of cutting bits 42 attached to the lower end thereof. The casing tube 40 is configured so that a plurality of casing tubes having a predetermined length can be added.

The excavating tool 36 is connected to the casing tube 4.
It is of a size that can be inserted and rotated in the inside of the casing 0, and after digging with the casing tube 40, in the case of a digging bucket, digging inside the casing tube 40 and taking in the excavated earth and sand, It can be discharged.

The above-described hydraulic motor 12 is connected to a hydraulic pump 52 via a switching valve 50 as shown in FIG. 3, and the hydraulic pump 52 pressurizes hydraulic oil in a hydraulic tank 54, and the switching valve 50 To the hydraulic motor 12 via the
The main flow path 56 on the discharge side of the hydraulic pump 52 and the hydraulic tank 54 as the low pressure side are connected via a relief valve 58.

The relief valve 58 controls the supply pressure P in the main flow path 56.
1 is a well-known device that opens when the pressure exceeds a preset set pressure P3, communicates the main flow path 56 with the hydraulic tank 54, and releases hydraulic oil to the hydraulic tank 54. The set pressure P
3 is preset in accordance with the allowable pressure of hydraulic equipment such as the hydraulic motor 12 and the hydraulic pump 52, for example.

The hydraulic motor 12 has a structure in which the displacement V per rotation can be varied. For example, a swash plate type in which the displacement V is varied by the inclination of the swash plate, a vane in which the displacement V is varied by moving a cam ring. Hydraulic motors of the oblique axis type and the like that vary the displacement volume V according to the inclination of the oblique axis are known.

When the hydraulic motor 12 is of a swash plate type, the displacement V is changed by changing the inclination of a swash plate (not shown), but the inclination of the swash plate depends on the pilot pressure P2 introduced into the working chamber 12a and the spring 12b. Determined by balance. That is, the inclination of the swash plate is proportional to the pilot pressure P2, and therefore, the displacement V is also proportional to the pilot pressure P2.

The working chamber 12a is connected to a pilot pump 61 via a pilot flow channel 60, and an electromagnetic control valve 62 is provided in the pilot flow channel 60. In the present embodiment, the electromagnetic control valve 62 uses an electromagnetic proportional pressure reducing valve, and reduces the operating oil pressure from the pilot pump 61 to a pilot pressure in accordance with an input command signal and guides the operating oil pressure to the action chamber 12a. .

The opening degree of the electromagnetic control valve 62 is determined by the balance between the secondary pressure and the electromagnetic force so that the secondary pressure is kept constant irrespective of the fluctuation of the operating oil pressure discharged from the pilot pump 61. It is well known. The pilot flow channel 60 on the discharge side of the pilot pump 61 is connected to the hydraulic tank 54 via a relief valve 64.

On the other hand, a pilot pressure sensor 66 for detecting the pilot pressure P2 introduced into the working chamber 12a is provided in the pilot flow passage 60 downstream of the electromagnetic control valve 62. The main flow path 56 has a supply pressure sensor 6 for detecting a supply pressure P1 supplied from the hydraulic pump 52 to the main flow path 56.
8 are provided.

Further, a depth measuring sensor 70 using an encoder for measuring the amount of movement of the wire 28 by detecting the rotation of the sheave 30 is provided. Electromagnetic control valve 6
2. The pilot pressure sensor 66, the supply pressure sensor 68, and the depth measurement sensor 70 are connected to the control device 100.

The control device 100 includes a well-known CPU 102,
An A / D conversion circuit 110 configured to convert an analog signal from the pilot pressure sensor 66, the supply pressure sensor 68, the torque setting unit 108 into a digital signal, and a digital signal into an analog signal. D which is converted to
/ A conversion circuit 112, an input circuit 116 for inputting signals from the depth measurement sensor 70 and the reset switch 114, and a display circuit 122 for outputting display signals to a set torque display section 118 and an output torque display section 120 made of liquid crystal or the like. They are interconnected via 124.

The CPU 102 controls the pilot pressure sensor 6
6. The signals from the supply pressure sensor 68 and the torque setting device 108 are passed through the A / D conversion circuit 110 to the depth measurement sensor 70.
And a signal from the reset switch 114 to the input circuit 116.
, While these data and the ROM 10
4. Based on the data in the RAM 106 and a control program stored in advance, the CPU 102
Signals are output to the electromagnetic control valve 62 via the control signal 2 and to both the display units 118 and 120 via the display circuit 122. still,
The torque setting unit 108 includes a setting knob 108a for setting a set torque of the hydraulic motor 12, and the setting knob 108a
By operating, the set torque can be varied.

The control device 100 calculates the pilot pressure P2,
The output torque Tm is calculated based on the supply pressure P1 detected by the supply pressure sensor 68, and the output torque display section 120
To be displayed. Assuming that the pressure on the suction side is P and the back pressure on the discharge side is almost 0, the torque T of the hydraulic motor 12 has the following formula (1). Here, V is the displacement per one rotation of the hydraulic motor 12 described above.

T = V × P / 2π (1) Since the displacement V is determined by the angle of the swash plate of the hydraulic motor 12, the displacement V is proportional to the pilot pressure P2. There is. Here, α is a proportionality constant obtained by an experiment or the like. Therefore, the torque T of the hydraulic motor 12 and the pilot pressure P2 have a relationship represented by the following equation (3).

V = α × P2 (2) T = α × P2 × P / 2π (3) The hydraulic motor is obtained by the following equation (4) in which the supply pressure P1 is substituted for the pressure P in the above equation (3). The output torque Tm when the operating oil of the supply pressure P1 is supplied to the engine 12 can be calculated.

Tm = α × P2 × P1 / 2π (4) Next, the excavation torque control processing performed in the control device 100 of the present embodiment will be described with reference to the flowchart of FIG. First, as shown in FIG. 6A, the casing tube 40 is set up at the place where the pile hole is formed, and the joint member 38 is connected to the casing tube 40. Then, the hydraulic motor 12 is driven by the rotation drive mechanism 10 to rotate the casing tube 40 via the transmission shaft 20 and the joint member 38. Further, the motor 8 is driven to lower the movable table 6 to apply a pushing force to the casing tube 40.

As a result, excavation is performed by the casing tube 40, and an unexcavated portion remains in the casing tube 40. When the excavation by the casing tube 40 is performed to a predetermined depth, the rotation of the casing tube 40 by the hydraulic motor 12 and the pushing of the casing tube 40 by the motor 8 are temporarily stopped.

Then, as shown in FIG. 6B, the connection between the joint member 38 and the casing tube 40 is disconnected, and the movable table 6 is raised. Next, the kelly bar 26 is passed through the slide hole 24 of the transmission shaft 20, and a drilling tool 36 is attached to the tip of the kelly bar 26. The excavator 36 is rotated by the hydraulic motor 12 via the transmission shaft 20 and the keriba 26, and the winch 34 is driven to feed out the wire 28 so that the excavator 36
Is lowered, and the casing tube 4 is
Excavate inside 0. The excavated earth and sand is taken into the excavation tool 36, and when the earth and sand is full, the wire 28 is wound up by the winch 34, and the excavation tool 36 is pulled out of the casing tube 40 to discharge the earth and sand.

Thereafter, the digging tool 36 is again lowered into the casing tube 40 for digging, and this is repeated.
The inside of the casing tube 40 is excavated. When the excavator 36 reaches near the tip of the casing tube 40,
The drilling tool 36 is pulled up, and a new casing tube 40 is added as shown in FIG.

Then, the joint member 38 is connected to the casing tube 40, and the hydraulic motor 12 is driven to rotate the casing tube 40, and the motor 8 is driven to apply a pushing force to the casing tube 40, and Excavation is performed with the tube 40.

At this time, the excavator 36 has a torque switching depth Ls
So that excavation by the excavator 36 is not performed. For example, the torque switching depth Ls is preferably a position that is substantially the same as the ground surface having a depth of 0 or a position that is slightly deeper than the ground surface, such as a position that does not hinder excavation by the casing tube 40.

When the above-mentioned excavation is performed, the control device 1
00 simultaneously executes excavation torque control processing. In this process, first, it is determined whether or not the reset switch 114 has been operated (step 200). The reset switch 114 is operated by an operator when the excavator 36 is on the surface of the earth when excavation is started by the excavator 36.

When the reset switch 114 is operated, the depth counter is cleared to 0 (step 20).
5). Next, the pulses output from the depth measurement sensor 70 are counted by the depth counter (step 210).
Then, the current depth L of the excavator 36 is calculated based on the count value (step 215). If the reset switch 114 has not been operated, step 2
The processing of 10 is executed.

Subsequently, the setting knob 108a is operated to read the set torque TS set in the torque setting unit 108 (step 220). The read set torque TS is displayed on the set torque display section 118. Next, it is determined whether or not the current depth L calculated by the processing of step 215 is deeper than the torque switching depth Ls (step 22).
5).

When the current depth L is smaller than the torque switching depth Ls, it is determined whether or not the set torque Ts read in the processing of step 220 is larger than the maximum torque Tk of the casing tube 40 (step 23).
0). Torque switching depth Ls and casing tube 40
The maximum torque Tk is stored in the RAM 106 or the like in advance, and the maximum torque Tk is the maximum torque that can be excavated without damaging the casing tube 40 when excavating with the casing tube 40.

When the set torque TS is larger than the maximum torque Tk of the casing tube 40, the maximum torque Tk of the casing tube 40 is newly substituted for the set torque TS regardless of the set torque TS read by the processing in step 220. (Step 235).
If the set torque TS is not larger than the maximum torque Tk, the process proceeds to the next step while keeping the set torque TS read by the processing of step 220.

That is, the current depth L is equal to the torque switching depth L
When it is shallower than s, it is determined that excavation by the casing tube 40 is being performed. And step 22
When the set torque TS set by the process of step 0 is larger than the maximum torque Tk of the casing tube 40, the set torque TS is changed to the maximum torque T of the casing tube 40.
k is limited so as not to exceed the maximum torque Tk of the casing tube 40.

On the other hand, the current depth L is the torque switching depth L
s, the set torque TS read by the processing of step 220 becomes the maximum torque TB of the digging tool 36.
It is determined whether it is greater than (Step 240). The maximum torque TB of the digging tool 36 is the maximum torque at which the digging tool 36 can excavate without breaking the digging tool 36, and is stored in the RAM 106 or the like in advance.

When the set torque TS is larger than the maximum torque TB of the digging tool 36, the maximum torque TB of the digging tool 36 is newly substituted for the set torque TS irrespective of the set torque TS read by the processing of step 220. (Step 245). If the set torque TS is not larger than the maximum torque TB, the process proceeds to the next step with the set torque TS read by the processing of step 220.

That is, the current depth L is equal to the torque switching depth L
When it is deeper than s, it is determined that excavation by the excavation tool 36 is being performed. When the set torque TS set by the process of step 220 is larger than the maximum torque TB of the digging tool 36, the set torque TS is
The maximum torque TB of the digging tool 36 as the maximum torque TB
Restrict so that it does not become above.

Next, the output torque Tm during excavation is calculated from the pilot pressure P2 detected by the pilot pressure sensor 66 and the supply pressure P1 detected by the supply pressure sensor 68 based on the above equation (4) (step). 250). This output torque Tm is displayed on the output torque display section 120.

Thereafter, the set torque Ts becomes equal to the output torque Tm.
Is determined (step 255). When the set torque TS is smaller than the output torque Tm, the output current to the electromagnetic control valve 62 is reduced (step 26).
0). As a result, the pilot pressure P2 decreases, and the output torque Tm of the hydraulic motor 12 decreases. On the other hand, when the set torque TS is larger than the output torque Tm, the output current to the electromagnetic control valve 62 is increased (step 26).
5). As a result, the pilot pressure P2 increases, and the output torque Tm of the hydraulic motor 12 increases. Step 26
After executing the processes of 0 and 265, the control process is repeatedly executed.

In this embodiment, the depth measurement sensor 70
The execution of the processing of steps 200 to 215 functions as depth measuring means, and the execution of the processing of steps 225, 235, and 245 functions as switching control means. Step 23
The execution of the processing of 0, 240 functions as a limiting unit.

The set torque TS may be changed by operating the setting knob 108a in accordance with the geology or the like while the excavation is being performed by the same excavator 36. The changed set torque TS is read and the set torque display unit 1 is read.
18 is displayed. In the present embodiment, it is determined whether or not the changed set torque TS exceeds the maximum torques Tk and TB (steps 230 and 240), and when it is exceeded, the set torque TS is set to the maximum torques TK and TB ( Steps 235 and 245), and the set torque TS becomes the maximum torque T
Limit the setting so that it does not exceed K and TB. For example, the operator misunderstands the type of the digging tool 36 used and operates the setting knob 108a to increase the large set torque T.
Even if S is set, the torque is limited so as not to exceed the maximum torques TK and TB.

The present invention is not limited to such an embodiment at all, and can be implemented in various modes without departing from the gist of the present invention.

[0048]

As described in detail above, the excavating torque control device of the present invention switches the maximum torque according to the depth, so that when switching excavation between the casing tube and the excavating tool, the complexity of switching can be eliminated. At the same time, there is an effect that damage or the like due to forgetting to switch can be prevented.

Further, if the limiting means is provided, even if the set torque exceeds the maximum torque due to misunderstanding or operation error, the set torque is limited to the maximum torque or less, so that breakage or the like can be prevented.

[Brief description of the drawings]

FIG. 1 is a front view of an excavating machine using an excavating torque control device as one embodiment of the present invention.

FIG. 2 is an enlarged sectional view of the rotation drive mechanism of the embodiment.

FIG. 3 is a circuit diagram showing a hydraulic system of the excavating torque control device according to the embodiment.

FIG. 4 is a circuit diagram showing an electric system of the torque control device for excavation according to the embodiment.

FIG. 5 is a flowchart illustrating an example of an excavation torque control process performed by the control device according to the embodiment.

FIG. 6 is an explanatory diagram showing an excavation step of the embodiment.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Excavation construction machine 2 ... Leader 6 ... Moving table 10 ... Rotation drive mechanism 12 ... Hydraulic motor 20 ... Transmission shaft 26 ... Kelly bar 28 ... Wire 34 ... Main winch 36 ... Excavation tool 40 ... Boom 50 ... Switching valve 52 ... Hydraulic pump Reference Signs List 60 pilot channel 61 pilot pump 62 electromagnetic control valve 64 relief valve 66 pilot pressure sensor 68 supply pressure sensor 70 depth measuring sensor 100 control device 108 torque setting device 118 setting torque display unit 120 Output torque display

Continued on the front page (72) Inventor Masami Kiriyama 1-1, Sanbonmatsu-cho, Atsuta-ku, Nagoya-shi, Aichi F-term (reference) 2D029 PA05 PB01 PC02 PD01

Claims (4)

[Claims] An output torque of a rotary drive mechanism that rotates a casing tube having a cutting bit attached to a tip thereof and a drilling tool inserted into the casing tube rotates a keriba attached to the tip portion to a set torque. In the excavation torque control device that regulates the depth of the excavation tool, according to the detected depth, the set torque to the maximum torque corresponding to the casing tube or to the excavation tool Switching control means for setting a maximum torque according to the torque. 2. The excavation torque control device according to claim 1, wherein said depth measuring means measures the depth based on a movement amount of a wire on which said kelly bar is suspended. 3. The apparatus according to claim 1, further comprising a limiting unit that sets the maximum torque to the set torque when the set torque is larger than the maximum torque switched by the switching control unit. The torque control device for excavation according to claim 2. 4. The digging torque control device according to claim 1, wherein the digging tool is a digging bucket.