JPH0380217B2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] This invention is a control device for an excavation rig suspended from a mobile crane such as a crawler crane or a truck crane, in which the excavation speed is automatically adjusted in response to changes in soil quality. The present invention relates to an excavation force control device that is adjusted according to the excavation force.

[Prior Art] A mobile crane is equipped with a boom that can be lifted up and down at the front of the upper revolving body, and has a winch mechanism that suspends an excavation device from the tip of the boom and winds up a rope that supports the excavation device. , a continuous wall excavator, an earth drill, etc. are well known, and all of these excavate by utilizing the weight of the bucket or kelly bar.

[Problems to be Solved by the Invention] In these excavators, when trying to control the penetration force of the excavation rig, it is generally necessary to Although it is controlled as an input, there are variations in the frictional force between the excavation equipment and the wall depending on the soil quality at the work site, and the specific gravity of the soil staying inside the excavation equipment also changes, so repeatability and accuracy may be affected. The problem remains,
On the other hand, when trying to control the excavation speed, it is difficult to respond to changes in soil quality and efficiency may be poor.

For example, when using constant speed control, if the speed remains constant even when soft ground is encountered, there is a problem in that even if there is a surplus in excavation capacity, the descending speed of the excavator will not change, resulting in a decrease in efficiency.

On the other hand, when using constant speed control, there is a problem that if the speed remains constant even when hard ground is encountered, the excavation capacity will be insufficient and excavation will become impossible.

This invention aims to solve the above-mentioned problems.The lowering speed of the excavator is kept constant at all times, and when hard ground is encountered, the lowering speed is increased. The purpose of this is to make it possible to slow down the lowering speed.

[Means for Solving the Problems] The present invention provides means for solving the above problems, and provides a load current for detecting the excavation load of an excavation equipment suspended by a hoisting rope such as a crawler crane. A detector is provided, and the excavation load detected by the detector is fed back to a control computer and compared with a preset value, and when the detected excavation load is smaller than the set value, the excavation load is changed to the set value. The lowering speed of the drilling rig is increased until the lowering speed is reached, and when the lowering speed of the drilling rig is within the set value, the lowering speed of the drilling rig is kept constant, and when the lowering speed of the drilling rig is greater than the set value, the lowering speed of the drilling rig is slowed down. It is designed so that it can be controlled.

[Example] Embodiments of the present invention will be described below with reference to the drawings.

In the figure, reference numeral 3 denotes a boom pivotally attached to the front part of the revolving upper body of the mobile crane so that it can be raised and lowered, and 8 denotes a mast similarly mounted near the rear end of the revolving upper body.

9 is a hoisting winch, and its hoisting drum 9
A hoisting rope let out from a suspends the excavation device 15 via the tip of the boom 3.

The excavation equipment 15 is equipped with a load current detector 42 that detects the excavation load (for example, a detector that detects the load current of a drive motor of a drum cutter, or a load cell installed at an appropriate location), and the load detector 42 is connected to a control computer 36.

The rotation of the engine 16 is transmitted to the sprocket 19 via the torque converter 17, and further to the hoisting clutch 9b or the hoisting clutch 9c via the chain 20, sprocket 21, and reduction gear 22.
is transmitted to.

The winch drum 9a of the hoisting winch 9 turns on the hoisting clutch 9b or the lower hoisting clutch 9c,
OFF enables forward/reverse rotation and free rotation,
The hoisting clutch 9b and the hoisting clutch 9c are turned on and off by an operating lever 23. A band brake 25 which is artificially braked by a hood pedal 24 is attached to the winch drum 9a.

Furthermore, a gear 26 is provided between the engine 16 and the torque converter 17, and a hydraulic pump 28 is driven by a gear 27 meshing with the gear 26. This hydraulic pump 28 is connected to an input port of an electro-hydraulic conversion valve 30 through a conduit 29, and an output port of the electro-hydraulic conversion valve 30 is connected to the multi-disc brake 18 provided between the torque converter 17 and the sprocket 19. It is connected to a brake cylinder 32 through a conduit 31 .

The brake cylinder 32 can change the pressing force between the fixed disc and the movable lining of the multi-disc brake 18 depending on the magnitude of the applied hydraulic pressure. The hydraulic pressure supplied to the brake cylinder 32 is controlled by the conversion valve 30, and by keeping this hydraulic pressure constant, a constant braking force can be obtained and the lowering speed of the excavation rig 15 can be controlled constant.

The electro-hydraulic conversion valve 30 is a valve that performs pressure control using an electric signal, and is communicated with a control unit 33 that sends an electric signal. It is connected to a control computer 36. The controller 35 includes
It has a dial 35a that allows you to arbitrarily adjust the voltage.

An excavation load setting device 39, a display panel 40, and a setting switch 41 are connected to the control computer 36.

The excavation load set by the excavation load setting device 39 is displayed on the display panel 40 and can be selectively output as an electric signal sent to the electro-hydraulic conversion valve 30 by a signal from the controller 35 and by the manual/automatic mode switch 34. selected.

[Operation] The operation of the present invention will be explained with reference to the above embodiments.

First, the width of the optimum excavation load is set using the excavation load setting device 39, and then set using the setting switch 41. Further, the dial 35a of the controller 35 is turned to set the braking force to be applied to the power transmission system. In that case, the dial 35a is set so that the maximum braking force can be obtained by turning the dial 35a fully, and the braking force becomes zero by turning the dial 35a to the minimum.

A rope is let out from the hoisting drum 9a to unwind the excavating device 15, and when the excavating device 15 reaches the bottom and excavation work is started, the manual/automatic mode switch 34 is switched to the automatic side. Then, a signal from the control computer 36 is transmitted to the electro-hydraulic conversion valve 30 via the control unit 33, and a brake force control command can be given to the power transmission system (winch system).

This brake force control command is given as follows.

Excavation load detector 42 provided in the excavation rig 15
The detected load current (for example, the load current of a drum cutter) is fed back to the control computer 36, where it is compared with the set value set by the excavation load setting device 39, and the excavation load is determined as the lower limit of the set value. When the brake force is lower than , a command value for relaxing the brake force is output from the control unit 33 to the electro-hydraulic conversion valve 30, and the descending speed of the drilling rig 15 is increased until the brake force is relaxed and reaches a predetermined value.

When the excavation load reaches the set value range, a command value to keep the braking force constant is output from the control unit 33 to the electro-hydraulic conversion valve 30.
The braking force is kept at a constant value and the descending speed of the excavation rig 15 is kept constant.

Furthermore, when the detected load increases beyond the upper limit of the set value, a command value is output to increase the braking force, and the descending speed of the excavation rig 15 is slowed down until it reaches a predetermined value.

In the embodiment, the descending speed of the excavation rig is controlled by controlling the brake force, but the rotational speed of the hoisting and lowering drum driving motor may also be controlled.

In this way, the detected load fed back from the excavation load detector 42 is compared with the target set value, and the excavation equipment 1 is fed back until the excavation load reaches the set value.
5, and when it reaches within the target setting value range, the descending speed of the drilling rig 15 is kept constant. On the other hand, when the detected load increases beyond the set value, the descending speed of the drilling rig 15 is increased to a predetermined value. drilling rig until reaching 15
This slows down the rate of descent.

The set value can be arbitrarily set by the operator, and the lowering speed of the drilling rig 15 is accelerated until the lower limit of the set value is reached, and after reaching the set value, the lowering speed of the drilling rig 15 is continued regardless of changes in the ground. Tooth tip load limitation that performs constant speed control to keep the speed constant, and when the excavation load increases beyond the upper limit of the set value, reduces the descending speed of the excavation device 15 to keep the tooth tip load below a predetermined value. It has a function.

As a result, a constant excavation force can be obtained with high precision regardless of changes in soil quality. For example, by keeping the set value constant, it is possible to excavate quickly when the excavation resistance is low in soft ground, or to perform excavation at a constant speed within a predetermined range. When excavating, hard ground is encountered and excavation resistance becomes large, excavation work is performed at a gentle excavation speed, which can improve both excavation efficiency and accuracy.

[Effect] According to the present invention, a load detector is provided to detect the excavation load of the excavation rig, and the excavation load detected by the load detector is fed back to a control computer to set a preset value. When the detected excavation load is smaller than the set value, the lowering speed of the excavating rig is increased until it reaches the set value, and when it is within the set value, the lowering speed of the excavating rig is kept constant. By controlling the lowering speed of the excavation rig to slow down when the value exceeds the set value, the lowering speed of the excavation rig can be kept constant at all times, that is, when the change in soil quality is within a certain range. ,
In soft ground, the descending speed can be increased; on the other hand, when the ground is hard and the excavation load exceeds a predetermined range, the descending speed can be reduced to keep the tooth tip load below a predetermined value. Even if there are variations in the frictional force between the excavation equipment and the wall surface depending on the soil quality, the excavation force can be controlled accurately, and a constant excavation force can be obtained in response to changes in the soil quality, making it possible to This has the effect of improving both efficiency and accuracy.

[Brief explanation of drawings]

The drawing is an explanatory diagram of an excavation force control device according to the present invention. 3: Boom, 9: Hoisting winch, 9a: Winch drum, 9b: Hoisting clutch, 9c: Lowering clutch, 15: Excavation equipment, 18: Multi-disc brake, 2
8: Hydraulic pump, 30: Electro-hydraulic conversion valve, 32: Brake cylinder, 33: Control unit, 3
4: manual/automatic mode switch, 35: controller, 36: control computer, 39: excavation load setting device, 40: display panel, 41: setting switch, 42: excavation load detector.

Claims (1)

[Claims] 1. A load detector for detecting the excavation load of an excavation device suspended by a hoisting rope such as a crawler crane, and the excavation load detected by the load detector is controlled. Feedback is sent to a computer and compared with a preset value, and if the detected excavation load is smaller than the set value, the lowering speed of the excavation equipment is controlled to be accelerated until the set value is reached. Excavator's excavation force control device. 2 Equipped with a load detector that detects the excavation load of an excavation rig suspended by a hoisting rope such as a crawler crane, and feeds back the excavation load detected by the load detector to a control computer. The excavation equipment is normally lowered at a constant lowering speed, and when the excavation load detected by the load detector becomes smaller than the preset value, the set value is compared with the preset value. An excavating force control device for an excavator, characterized in that the lowering speed of the excavator is controlled to be accelerated until the lowering speed of the excavator is reached. 3 Equipped with a load detector that detects the excavation load of an excavation rig suspended by a hoisting rope such as a crawler crane, and feeds back the excavation load detected by the load detector to a control computer. An excavation force control device for an excavator, characterized in that the excavation force control device compares with a preset value and controls the lowering speed of the excavator to be slowed when the detected excavation load becomes larger than the preset value. 4 Equipped with a load detector that detects the excavation load of the excavation equipment suspended by a hoisting rope such as a crawler crane, and feeds back the excavation load detected by the load detector to a control computer. The excavation equipment is normally lowered at a constant lowering speed, and when the excavation load detected by the load detector becomes larger than the preset value, the set value is compared with the preset value. An excavating force control device for an excavator, characterized in that the lowering speed of the excavator is controlled to be slowed until the lowering speed of the excavator is reached. 5 Equipped with a load detector that detects the excavation load of the excavation equipment suspended by a hoisting rope such as a crawler crane, and feeds back the excavation load detected by the load detector to a control computer. An excavation force control device for an excavator, characterized in that when the detected excavation load is compared with a preset value, the lowering speed of the excavator is controlled to be kept constant. . 6 Equipped with a load detector that detects the excavation load of an excavation rig suspended by a hoisting rope such as a crawler crane, and feeds back the excavation load detected by the load detector to a control computer. When the detected excavation load is smaller than the set value, the lowering speed of the excavation rig is increased until it reaches the set value, and when it is within the set value, the lowering speed of the excavation rig is increased. Keep the downward speed constant,
An excavation force control device for an excavator, characterized in that when the lowering speed of the excavator is greater than a set value, the lowering speed of the excavator is controlled to be slowed down.