JP2000109291A - Control system of hoisting winch - Google Patents

Abstract

PROBLEM TO BE SOLVED: To detect landings of free-falling slung loads accurately and to brake the drive of winches at proper timing. SOLUTION: A rotation sensor 21 detects the amount of rotation αof a drum 41 and passes it to a controller 20 that computes the acceleration (a) of the drum 41. In free fall, minus acceleration (a) of the drum 41 proves a slung load 45 is on the ground, upon which a solenoid selector valve 12 receives control signals to actuate a brake device 6, which in turn brakes the drum 41 being driven.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a control device for a winch mounted on a crawler crane or the like.

[0002]

2. Description of the Related Art The work performed by free-falling a hoisting winch mounted on a crawler crane includes a work by a dynamic compaction method and an excavation work using a bucket. The dynamic consolidation method is a method used to improve the ground over a relatively wide area, for example, when constructing an airport runway. Is dropped a predetermined number of times from a predetermined height, and the ground is improved by the fall energy. In such work, from the viewpoint of work efficiency,
It is required that the weight is dropped as many times as possible as soon as possible. For this purpose, it is necessary to apply a brake simultaneously with the landing of the weight that has fallen freely and to prevent the hoisting rope from being unnecessarily extended. Similarly, in the case of performing an excavation work by digging into a bucket (for example, a clamshell work or a grab bucket work), in order to obtain a required excavation amount as soon as possible, apply a brake simultaneously with landing of the bucket, There is a need to prevent extra payoff of the rope.

[0003] When the brake is applied early during the above-mentioned dynamic consolidation method or the operation using a bucket, a part of the falling energy of the weight or the bucket deforms the friction energy and the boom during braking. It is converted into energy, etc., which results in energy loss and deterioration of work efficiency, and excessive tension acts on the hoisting rope, which may cause unstable vehicle conditions and severe damage to the hoisting rope. There is. Conversely, if the brake is applied at a late timing, the rope will be extended even after landing due to the inertia of the winch drum, and the winch drum will be in a turbulent state, so it is necessary to rewind the rope around the winch drum. Efficiency deteriorates. Further, since no extra tension is applied to the rope that is unreeled after landing, the rope is in a state where the control is not effective, which is problematic. In the bucket work, work is frequently performed under conditions where it is difficult to visually check the bucket, such as underground or on the sea floor. Therefore, it is particularly difficult to make the brake application timing appropriate. In order to solve such a problem relating to the timing at the time of the brake operation, Japanese Utility Model Publication No. 7-11109 discloses an apparatus that automatically applies a brake after a weight (weight) lands during a free fall. It has been disclosed.

In the device described in this publication, the tension of a pendant rope connected to a hook is detected by a load cell, and when the detected value becomes a value corresponding to the weight of the hook, it is determined that the weight has landed, and the solenoid valve is switched. Output a signal. The supply of the pressure oil to the brake cylinder is stopped by the switching signal, the negative brake is operated, and the driving of the winch drum after landing is stopped.

[0005]

However, when the weight lands, the rope tension fluctuates due to the impact of the boom shaking and vibration acting on the fuselage, making it difficult to accurately detect the rope tension. Therefore, in the apparatus that determines the landing of the weight based on the rope tension as in the apparatus described in the above publication, the accuracy of the landing determination is deteriorated, and it is difficult to brake the winch at an appropriate timing. In addition, since the rope tension corresponding to the weight of the hook is very small, it is difficult to make an accurate landing determination using a device that determines landing based on a small value as in the device described in the above publication.

SUMMARY OF THE INVENTION An object of the present invention is to provide a hoisting winch control device that can accurately determine the landing of a suspended load during a free fall and brake the winch at an appropriate timing.

[0007]

Means for Solving the Problems (1) Referring to FIG. 1 showing an embodiment, the invention of claim 1 is a hydraulic pressure driven to hoist or lower by a command from an operation lever 7. A hoisting winch control device including a motor 2 and a hoisting drum 41 on which a driving torque from the hydraulic motor 2 is transmitted in a hoisting or lowering state in a transmitting state and a suspended load 45 is free fall in a non-transmitting state. Applied to Then, acceleration calculating means 20, 2 for calculating the acceleration a of the suspended load 45
1 and a brake device 6 for stopping the driving of the hoisting drum 2
The above object is achieved by providing the control means 12 and 20 for controlling the operation of the brake device 6 by outputting a stop command when the acceleration a calculated by the acceleration calculation means 20 and 21 becomes a predetermined value or less. You. (2) The invention according to claim 2 provides acceleration calculation means 20, 21
When the acceleration a calculated as follows becomes a negative value (<0),
The control means 12 and 20 control the operation of the brake device 6 by outputting a stop command.

[0008] In the section of the means for solving the above-mentioned problems, which explains the configuration of the present invention, the drawings of the embodiments of the present invention are used to make the present invention easier to understand. However, the present invention is not limited to this.

[0009]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a hydraulic circuit diagram illustrating a configuration of a winch control device according to an embodiment of the present invention. As shown in FIG. 1, a winch control device according to the present embodiment includes a variable displacement main pump 1, a hydraulic motor 2 driven by pressure oil discharged from the main pump 1, and a hydraulic pump driven by the main pump 1. A directional control valve 3 for controlling the flow of pressure oil supplied to the motor 2;
A hoisting winch 4 driven by hoisting and lowering by a driving torque from the motor; a clutch device 5 for transmitting or not transmitting a driving torque from the hydraulic motor 2 to the hoisting winch 4;
A brake device 6 for stopping the driving of the hoisting winch 4, an operating lever 7 for inputting a hoisting / lowering command of the hoisting winch 4 by an operator, pilot valves 8A and 8B operated by the operating lever 7, and a pilot valve 8A , 8B, a hydraulic pilot switching valve 10 for controlling the driving of the clutch device 5, and a pilot valve 8.
A, 8B pilot pressure from hydraulic pilot switching valve 1
A shuttle valve 11 for leading to a pilot port 0, an electromagnetic switching valve 12 for controlling the driving of the brake device 6, and a controller 20 for outputting a switching signal to the electromagnetic switching valve 12.

The hoisting winch 4 has a winch drum 41 around which a winch rope 42 is wound. The winch rope 42 is connected to the hook F via a sheave 44 provided at the end of the boom 43, and the winch rope 42 is wound or unwound by the rotation of the winch drum 41, and the suspended load 45 suspended by the hook F is raised and lowered. I do. An output shaft 2a connected to the hydraulic motor 2 via the speed reducer 13 is inserted through the center of the drum 41, and a clutch device 5 is connected to the output shaft 2a, and the clutch device 5 rotates integrally with the output shaft 2a. I do. The clutch device 5 is a clutch cylinder 5
When the pressure oil from the pilot pump 9 is supplied to the rod-side oil chamber of the clutch cylinder 51, the cylinder 5
1 is retracted, the winch drum 41 and the clutch device 5 are separated from each other, and the clutch is released. Further, when the supply of the pressure oil from the pilot pump 1 is stopped, the cylinder 51 is extended by the urging force of the spring provided on the clutch cylinder 51, and the winch drum 41 and the clutch device 5 come into contact with each other and the clutch is connected. It is said.

The brake device 6 includes a brake pedal 61 which is depressed by an operator and an electromagnetic switching valve 1.
A pressure reducing valve 62 that reduces the primary pressure P1 from the pressure reducing valve 2 to a secondary pressure according to the pedal operation, a brake cylinder 63 that is expanded and contracted by the secondary pressure P2 from the pressure reducing valve 62, and a cylinder rod 63a via a link 64 And a brake band 65 connected thereto. When the brake pedal 61 is not operated, the pressure reducing valve 62 functions as a mere opening valve, and the secondary pressure P
2 is the maximum (= P1), and the brake pedal 61
Is operated to the maximum, the degree of pressure reduction of the pressure reducing valve 62 becomes maximum, and the secondary pressure P2 becomes equal to the tank pressure P0. When the secondary pressure P2 (= P1) is supplied to the head-side oil chamber of the cylinder 63, the cylinder 63 is contracted and the brake band 65 is expanded, whereby the brake drum 41a formed integrally with the winch drum 41 is formed. Is released from the brake band 65 and the brake is released. When the supply of the pressure oil to the head-side oil chamber of the cylinder 63 is stopped, the cylinder 63 is extended by the urging force of the spring provided in the cylinder 63, and the brake band 65 is contracted. , A braking force is applied, and the brake is activated.

The controller 20 includes a rotation amount sensor 21 for detecting the rotation amount of the drum 41, a pressure switch 22 for detecting the presence or absence of a pilot pressure from the shuttle valve 11 in accordance with the operation of the operation lever 7, and a power switch 23. Are connected, and an input signal is input by these. The controller 20 executes the processing described below, and executes the electromagnetic switching valve 1
2 outputs an on / off signal to the solenoid. When an ON signal is output to the electromagnetic switching valve 12, the solenoid is excited and the electromagnetic switching valve 12 is switched to the position (A). When an OFF signal is output, the solenoid is demagnetized and the electromagnetic switching valve is moved to the position (B). Is switched to.

Here, the general behavior of the drum 41 during a free fall will be described. FIG. 2 (a)
It is a figure which shows the speed characteristic of the drum 41 at the time of the free fall of the suspended load in the brake release state, and FIG.2 (b) is a figure which shows the acceleration characteristic of the drum 41. As shown in FIG. 2, the suspended load 45 from the start of the free fall to the landing.
Falls free due to gravitational acceleration, a positive acceleration a1 (> 0) acts on the drum 41, and the drum angular velocity v gradually increases. When the suspended load 45 lands, a negative acceleration a2 (<0) such as a friction loss due to the rotation of the drum 41 or the rotation of the sheave 44 acts on the drum 41, and the drum angular velocity v
Gradually decreases. As described above, a correlation is recognized between the behavior of the suspended load 45 and the acceleration a. In the present embodiment, when the acceleration a becomes smaller than a predetermined value (a <0) by focusing on this correlation. It is determined that the suspended load 45 has landed.

Next, the processing executed by the controller 20 will be described. FIG. 3 is a flowchart illustrating an example of a process executed by the controller 20. This flowchart starts when the power switch 23 is turned on. In step S1, it is determined whether or not the pressure switch 22 is turned on, that is, whether or not the operation lever 7 is operated. When step S1 is affirmed, the process proceeds to step S4, and when denied, the process proceeds to step S2. In step S2, the signal α from the rotation amount sensor 21 is read, and the angular acceleration a of the drum 41 is calculated using the relationship of the following equation (1).

A = d ² (Δα) / dt ² (l) where, Δα: the amount of change in the rotation amount α per minute time dt Next, in step S3, the angular acceleration a is a negative value (minus).
It is determined whether or not. If step S3 is negative, the process proceeds to step S4, in which an off signal is output to the electromagnetic switching valve 12, and the process returns. If step S3 is affirmed, step S5 is reached.
And outputs an ON signal to the electromagnetic switching valve 12 and returns.

Next, the operation of the present embodiment will be described more specifically. (1) Hoisting / Unwinding Operation When the operating lever 7 is operated to the hoisting side or the lowering side to perform the hoisting / unwinding operation, the pilot valve 8A or 8B is driven in accordance with the operation amount, and the pilot pump 9 is operated.
From the pilot port 3A or 3
B. As a result, the control valve 3 is moved to the position (a).
Side or the position (b) side, and the main pump 1
Is supplied to the hydraulic motor 2 via the control valve 3 and the hydraulic motor 2 is driven. At the same time, the pressure oil from the pilot valves 8A and 8B is supplied to the pilot port of the hydraulic pilot switching valve 10 via the shuttle valve 11, and the hydraulic pilot switching valve 10 is switched to the position (A), and the pressure switch 22 Is turned on, the controller 20 outputs an off signal to the electromagnetic switching valve 12, and the position is switched to the position (b). As a result, the clutch cylinder 51 is brought into the tank pressure by the tank pressure, and the pressure oil from the pilot pump 9 is supplied to the brake cylinder 63 via the electromagnetic switching valve 12 and the pressure reducing valve 62, and the brake is released. Is done. As a result, the driving torque of the hydraulic motor 2 is transmitted to the drum 41, and the drum 41 is driven up or down, and the suspended load 45
Is raised and lowered at a speed corresponding to the operation amount of the operation lever 7. In order to stop the driving of the drum 41, the supply of the pressure oil to the brake cylinder 63 may be stopped by operating the brake pedal 61.

(2) Free Fall Operation In order to perform a free fall operation with the power switch 23 turned on, first, the operating lever 7 is hoisted to lift the suspended load 4.
5 is wound up to a predetermined height, and then the operation lever 7 is operated to the neutral position. Then, the supply of the pressure oil from the pilot valves 8A and 8B is stopped, the control valve 3 is driven to the neutral position, the rotation of the hydraulic motor 2 is stopped, and the hydraulic pilot switching valve 10 is switched to the position (b). Can be Thereby, the pressure oil from the pilot pump 9 is supplied to the clutch cylinder 51 via the hydraulic pilot switching valve 10, the clutch device 5 is released, the drum 41 is freely rotated, and the suspended load 45 falls free. When the suspended load 45 lands and the acceleration a of the drum 41 becomes negative, the electromagnetic switching valve 1
2 is switched to the position (a). As a result, the head-side oil chamber of the brake cylinder 53 has the tank pressure P0, and the brake device 6 is operated to prevent the rotation of the drum 41. When the power switch 23 is off, the electromagnetic switching valve 12 is always switched to the position (a), and the brake device 6 is not automatically operated.

As described above, according to the present embodiment, the landing of the suspended load is determined based on the change in the acceleration a of the drum 41.
Since the brake device 6 is operated, the accuracy of the landing determination is improved, the suspended load 45 can be braked at an appropriate timing, and the working efficiency is improved. In addition, when the sign of the acceleration changes from positive to negative, it is determined that the suspended load has landed, so that the landing can be easily determined, and it is not necessary to calculate the absolute value of the acceleration a accurately. It is not necessary to increase the accuracy of the image more than necessary. Further, since the brake device 6 is operated by on / off control of the electromagnetic switching valve 12, the circuit configuration is simplified and the circuit can be easily incorporated into an existing circuit.

In the above description, when the operation lever 7 is operated to the neutral position, the suspended load 45 free-falls. However, actually, when the operation lever 7 is operated to the neutral position, the negative brake is activated. It is desirable to be able to select a mode in which the negative brake is released during neutral and the suspended load 45 free-falls.

In the above-described embodiment, when the acceleration a becomes negative, the landing of the suspended load is determined and the brake is applied. The brake may be applied when the value becomes smaller than the value a1 (> 0) (a <a1). In the above embodiment, the rotation amount α of the drum 41 is
, The acceleration a of the drum 41 is calculated, but the invention is not limited to this, and the rotation amount of the sheave 44 and the speed of the rope 42 are detected, and the acceleration is calculated based on the detected rotation amount or the acceleration sensor is provided. May be directly detected. Further, an acceleration other than that of the drum 41 correlated with the behavior of the suspended load 45 may be calculated, and the landing of the suspended load 45 may be determined based on the calculated acceleration. Furthermore, in the present embodiment, the same brake device 6 is used for the hoisting and lowering work and the free fall work, but a dedicated brake device may be used.

In the correspondence between the above embodiment and the claims, the controller 20 and the rotation amount sensor 21 constitute acceleration calculating means, and the electromagnetic switching valve 12 and the controller 20 constitute control means, respectively.

[0021]

As described above in detail, according to the present invention, when the acceleration of the suspended load becomes a predetermined value or less, a stop command is output to the brake device to stop driving the hoist drum. The accuracy of the landing judgment is improved, and the suspended load can be braked at an appropriate timing. According to the second aspect of the present invention, since the driving of the hoist drum is stopped when the sign of the acceleration becomes negative, it is not necessary to calculate the absolute value of the acceleration, and the apparatus is inexpensive.

[Brief description of the drawings]

FIG. 1 is a circuit diagram of a winch control device according to an embodiment of the present invention.

FIG. 2 is a diagram illustrating a drum speed characteristic and a drum acceleration characteristic during a free fall.

FIG. 3 is a diagram showing an example of a flowchart as a process executed by a controller.

[Explanation of symbols]

 2 Hydraulic motor 5 Clutch device 6 Brake device 7 Operating lever 12 Solenoid switching valve 20 Controller 21 Rotation amount sensor 41 Winch drum 45 Suspended load

 ──────────────────────────────────────────────────の Continuing on the front page (72) Inventor Koji Funato 650 Kandamachi, Tsuchiura-shi, Ibaraki Pref.Hitachi Construction Machinery Co., Ltd. (72) Inventor Teruo Igarashi 650, Kandamachi, Tsuchiura-shi, Ibaraki Hitachi Construction Machinery Co., Ltd. Inside the Tsuchiura Plant (72) Inventor Tsutomu Udagawa Inside the Tsuchiura Plant, Hitachi Construction Machinery Co., Ltd.

Claims (2)

[Claims] 1. A hydraulic motor driven to hoist or lower by a command from an operation lever, and a hoisting or lowering drive is performed in a transmission state of a driving torque from the hydraulic motor, and a suspended load is free in a non-transmission state. A hoisting winch control device having a hoisting drum to be fallen; an acceleration calculating means for calculating the acceleration of the suspended load; a brake device for stopping the driving of the hoisting drum; Control means for outputting a stop command and controlling the operation of the brake device when the acceleration becomes equal to or less than a predetermined value. 2. The winding system according to claim 1, wherein the control unit controls the operation of the brake device by outputting a stop command when the acceleration calculated by the acceleration calculation unit becomes a negative value. Upper winch control device.