JP2553264Y2 - Excavator torque control device - Google Patents

Description

[Detailed description of the invention]

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a torque control device for an excavator, and more particularly to a torque control device for an excavator having rotating tools that rotate in opposite directions.

[0002]

2. Description of the Related Art Generally, an excavator for excavating a solid hole in the ground to improve the ground or to form a pile is generally a leader mast installed on a ground work machine 1 as shown in FIG. The drive unit 4 moves along the guide rail 3 on one side of the work machine 2
It is supported by the upper winch via a wire 5 so as to be able to ascend and descend. A screw auger, a stirring rod, a casing auger, etc. (collectively referred to as a rotating tool) are provided at a lower portion of the driving section 4 to drive the rotating tool 6. The electric motor in the part 4,
It is rotationally driven through a speed reducer to excavate a solid hole in the ground.

In this type of excavator, the rotating tools 6 are provided as a pair of right and left, and the rotating tools 6 are driven to rotate in opposite directions to each other to cancel the rotational moment suspended on the leader mast 2 and to provide the leader mast 2 and the related In order to prevent damage to the member to be removed and to prevent the stability from lowering, if the overload occurs on one of the rotating tools 6 due to the nature of the excavated ground, particularly the presence of cobblestones, etc. There is a problem that the stability is lowered.

Therefore, the rotating tools 6 are independently driven to rotate by motors, and the current values of these motors are detected. When the difference between the current values exceeds a set value, a signal is transmitted to the rotating tools 6 to output the signals. There is an apparatus in which occurrence of a load is notified to solve the above-mentioned problem (Japanese Utility Model Publication No. 63-38283).

[0005]

However, the technique described in the above publication, however, infers that an overload has occurred due to the difference between the current values of the motors, and indirectly knows the rotational moment applied to the leader mast. Therefore, there is a problem that reliability cannot be denied, and it cannot be applied to an excavator having a structure in which rotation is branched from a single moker to drive each rotating tool. In view of the above, the present invention provides a torque control device for an excavator that detects an overload by using a reaction force when one of the rotating tools is overloaded and obtains an overload occurrence signal. It was made for the purpose of.

[0006]

In order to solve the problems of the above-mentioned prior art, the present invention provides a machine frame which can be moved up and down along a leader mast established on the ground, and a drive unit is provided on the machine frame. Is mounted so as to be pivotable in a horizontal plane, and a pair of right and left load meters is installed on the left and right portions between the front surface of the machine frame and the rear surface of the drive unit. The load detected by this load meter and a preset setting are set. It has a control unit for comparing and calculating a value and transmitting an overload occurrence signal when the value exceeds a set value.

[0007]

[Function] When one of the rotating tools encounters an obstacle such as a cobblestone in the ground when rotating a left and right rotating tool mounted on the driving unit to drill a hole in the ground and excavate a solid hole. When the rotating tool is overloaded, the rotation is braked and the reaction force is transmitted to the driving unit, and the driving unit turns in a horizontal plane, and an overload between the driving unit and the machine frame is applied. Side load cell receives compressive load. When the load exceeds the set value, the control unit transmits an overload occurrence signal, and the signal is used to take measures such as stopping the drive unit and issuing an alarm.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below with reference to embodiments shown in the drawings.

The illustrated embodiment illustrates a case where the present invention is applied to the excavator shown in FIG. 4, and FIG. 1 is a plan view seen from a position corresponding to an arrow AA in FIG. 2 is a side view showing a cross section of a part of the drive unit 4 and its peripheral structure.

In the present invention, a plate-shaped machine frame 7 is supported on the guide rail 3 of the leader mast 2 via slide fittings 8 and 8 so as to be able to move up and down. The bearings 9, 9 protrude forward, and the upper and lower ends of the rear part of the drive unit 4 are located between the bearings 9, 9.
The support member 10 is pivotally supported in a horizontal plane.

The driving section 4 is suspended by a wire 5 wound around a sheave 11 supported on the upper surface thereof.
Is moved up and down along the guide rail 3 with the machine frame 7. In FIG. 1, reference numerals 6a and 6a denote rotating tools.

Load cells 13, 13 are mounted on the left and right portions near the center in the vertical direction of the machine frame 7. The illustrated embodiment shows a case where a hydraulic cylinder is used. The piston rod 15 of the hydraulic cylinder 14 is disposed so as to penetrate the machine frame 7 and abut on the rear surface 4 a of the drive unit 4. One of the piston rods is pressed at the time of turning movement.

As shown in an example in FIG. 3, a control circuit constituting the control section 16 is connected to a hydraulic pipe 17 connected to the pressurizing chamber 14a of each of the hydraulic cylinders 14, 14 constituting the load cells 13, 13. , Pressure transducer 18 for converting oil pressure to an electric signal
The pressure transducer 18 is connected to an arithmetic unit 19 by a cable 20. This arithmetic unit 19
The pre-input set value is compared with the detected pressure value output from the pressure transducer 18 and a stop signal for stopping the electric motor 21 of the drive unit 4 when the detected value exceeds the set value is output. To the control panel 22 of the excavator and display the detected value on the display 23. In the control panel 22, it is optional to stop the motor 21 after a lapse of a predetermined time after receiving the stop signal (overload occurrence signal).
In addition to the stop, an alarm may be issued. FIG.
Reference numeral 24 denotes an accumulator for alleviating the impact applied to the load meter (leader mast) and eliminating fine amplitude of the load.

Next, the operation of the above embodiment will be described.

The left and right rotating tools 6a mounted on the driving unit 4
6a is rotated in the opposite direction as shown by the arrow in FIG. 1, and when excavating a solid hole in the ground, one of the rotating tools 6a shown in FIG. When the rotation of the rotating tool 6a is hindered and an overload occurs, the reaction force of the rotating tool 6a is transmitted to the driving unit 4, and in the case of FIG. Turning force acts. The rotation of the drive unit 4 presses the load meter 13 on the rotating tool 6a side, that is, the piston rod 15 of the hydraulic cylinder 14, and the pressing causes the pressurizing chamber 1
The hydraulic pressure in 4a increases. This oil pressure is converted into an electric signal in the pressure converter 18, input to the arithmetic unit 19 and compared with a set value, and when the oil pressure exceeds the set value, a stop signal for stopping the motor 21 is output as an overload generation signal. This signal is input to the control panel 22 to stop the motor 21. Similarly, when the other rotating tool 6b is overloaded, the piston rod 15 of the hydraulic cylinder 14, which is the load meter 13 on the rotating tool 6b side, is pressed, and an overload occurrence signal is transmitted to stop the motor 21. Let it. In this way, when an overload occurs in the rotating tools 6a and 6b, the situation is immediately grasped, and a countermeasure can be taken before the leader mast 2 and its related members are damaged or lack stability.

In the illustrated embodiment, the load cells 13, 1
The case where a hydraulic cylinder is used as 3 has been described, but it goes without saying that a load cell or the like may be used.

[0017]

As described above, according to the present invention, when an overload is applied to a rotating tool, a driving unit is turned by utilizing the reaction force, and the load meter is pressed by the turning of the driving unit. The overload is detected by making
The overload can be directly detected based on the load fluctuation applied to the rotating tool itself, and therefore, the reliability of the overload detection can be greatly improved. In addition, the present invention can be applied to an excavator of a type in which the left and right rotating tools are driven by a single motor, and has an effect of being versatile.

[Brief description of the drawings]

FIG. 1 is a plan view of a main part of the present invention.

FIG. 2 is a side view of the same part in section.

FIG. 3 is a control circuit diagram.

FIG. 4 is a side view showing an example of an excavator to which the present invention is applied.

[Explanation of symbols]

 2 Leader mast 3 Guide rail 4 Drive unit 6 (6a, 6b) Rotating tool 7 Machine frame 9 Bearing unit 10 Shaft 13 Load cell 14 Hydraulic cylinder 15 Piston rod 16 Control unit 21 Electric motor

Claims (1)

(57) [Scope of request for utility model registration] A machine frame which can be moved up and down along a leader mast established on the ground is provided. A drive unit is mounted on the machine frame so as to be pivotable in a horizontal plane, and a front surface of the machine frame and a rear surface of the drive unit are provided. A pair of right and left load cells is installed on the left and right parts between the two, and the load detected by this load cell is compared with a preset set value, and when the value exceeds the set value, an overload occurrence signal is generated. A torque control device for an excavator, comprising a control unit for transmitting a signal.