JPH10297877A - Turn controller of crane - Google Patents

Abstract

PROBLEM TO BE SOLVED: To control the turning speed following the turning command value of an operator while the turn of a turning body is controlled so that a lifted cargo is prevented from being oscillated by detecting the load condition of a hydraulic motor for turning. SOLUTION: When a lifted cargo is oscillated as a turning body is turned, the detected pressure becomes different between the pressure detectors 12A, 12B, and the cargo oscillation is detected based on the differential pressure and the operational direction of an operation lever 5. The angle of tiltation of a variable capacity hydraulic pump 3 is changed by an angle of tilation changing device to delay the turning speed of the turning body when the cargo oscillation condition is detected where the turn of the lifted cargo is behind the turn of the turning body, and to increase the turning speed when the cargo oscillation condition is detected where the turn of the lifted cargo is ahead of the turn of the turning body. As a result, the cargo oscillation is suppressed.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a crane turning control device.

[0002]

2. Description of the Related Art Conventionally, for example, as a device for controlling the drive of a fluid pressure actuator in accordance with the operation amount of an operation lever,
The so-called speed control type is generally well known.
This will be described with reference to the turning of the crane. FIG. 6 is an overall configuration diagram of a crane, and FIG. 7 is a circuit configuration diagram of a conventional turning control device. As shown in FIG. 6, the crane has a traveling body 61, a revolving body 62 mounted on the traveling body 61 and capable of turning, and a boom 63 provided on the revolving body 62, and a wire is provided via a sheave 64. The suspended load 66 is lifted by the hook 65 connected to the rope.

As shown in FIG. 7, a hydraulic circuit for turning the revolving unit 62 includes a prime mover 101, a variable displacement hydraulic pump 3 driven by the prime mover 101, and a pressure discharged from the variable displacement hydraulic pump 3. A turning hydraulic motor 2 driven by oil, a turning direction control valve 1 for controlling the flow of pressure oil supplied from the variable displacement hydraulic pump 3 to the turning hydraulic motor 2, and a tank 8 by the direction control valve 1. A pressure compensating valve 4 for controlling the pressure of the bleed-off pressure oil, an operation lever 5 for inputting a turning command by an operator, and a pressure oil to a pilot hydraulic circuit for transmitting an operation amount of the operation lever 5 to the direction control valve 1. And a pilot hydraulic pressure source 7 to be supplied. The pressure compensating valve 4 is configured to control the pressure of the bleed-off pressure oil to a pressure equivalent to the driving pressure of the turning hydraulic motor 2 by guiding the driving pressure of the turning hydraulic motor 2.

In such a conventional turning device, the driving pressure of the turning hydraulic motor 2 is equal to the pressure of the bleed-off pressure oil as described above.
If the opening area is the same, the pressure difference before and after the directional control valve 1 becomes equal irrespective of the turning load, and the flow rate to the turning hydraulic motor 2 side and the flow rate to the bleed side become the discharge of the variable displacement hydraulic pump 3. The flow is distributed according to the opening area ratio of the turning direction control valve 1, and the flow can be distributed as input by the operator regardless of the load pressure.

On the other hand, as a method of detecting a change in the load acting on the hydraulic motor and controlling the turning speed to the target turning speed, for example, a method described in Japanese Patent Laid-Open No. 6-10905 is known. I have. In this method, the pump discharge pressure and the motor load pressure, that is, the pressures before and after the directional control valve are detected, and the spool of the directional control valve is detected so that the hydraulic motor can operate at the same speed even when the load acting on the hydraulic motor is different. The displacement is controlled. Therefore, the turning speed can be controlled to be the same regardless of the load of the motor.

[0006]

However, in a crane, it may not always be desirable to always accurately obtain a turning speed corresponding to the operation amount and load of the operation lever. For example, when a crane turns, a suspended phenomenon is suspended via a wire rope, and a vibration phenomenon called pendulum (a pendulum motion) occurs. The swing of the suspended load acts as a load on the turning hydraulic motor. However, in the above-described conventional technique, the swing operation is performed irrespective of the load swing in order to forcibly achieve the swing speed according to the swing command of the operator. become. Therefore, it is difficult for the operator to grasp the load state on the turning hydraulic motor due to the load swing, and it is necessary to perform the operation carefully so that the suspended load does not swing, which requires the labor and the skill of the operator. .

SUMMARY OF THE INVENTION It is an object of the present invention to provide a crane for controlling a turning speed according to a turning command of an operator while detecting a load state on a turning hydraulic motor and controlling a turning of a revolving body so that a suspended load does not swing. It is to provide a turning control device.

[0008]

FIG. 1 shows an embodiment of the present invention.
Referring to FIG. 6, the present invention provides a variable displacement hydraulic pump 3, a swing hydraulic motor 2 that drives a swing body 62 with pressure oil discharged from the variable displacement hydraulic pump 3,
The turning direction control valve 1 for controlling the direction of the pressure oil supplied from the variable displacement hydraulic pump 3 to the turning hydraulic motor 2 and the pressure of the bleed-off circuit communicating from the turning direction control valve 1 to the tank 8 are used for turning. The present invention is applied to a crane turning control device provided with a pressure compensating valve 4 for setting a pressure corresponding to the driving pressure of the hydraulic motor 2 and an operating means 5 for switching the turning direction control valve 1. Operation direction detecting means 11 for detecting, load state detecting means 12A and 12B for detecting the load state of the turning hydraulic motor 2, and suspension based on signals from the operation direction detecting means 11 and load state detecting means 12A and 12B. When the load swing state in which the load 66 is later than the swing of the revolving unit 62 is detected, the discharge flow rate is reduced, and the load swing state in which the suspended load 66 is ahead of the swing of the revolving unit 62 is detected. Rutoki controls the tilt angle of the variable displacement hydraulic pump 3 to increase the discharge flow rate control means 1
The above object is achieved by providing 0 and 13.

In the section of the means for solving the above-mentioned problems, the present invention is associated with the drawings of the embodiments for easy understanding of the present invention. However, the present invention is not limited to the embodiments. Absent.

[0010]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a hydraulic circuit diagram showing a configuration of a crane turning control device according to an embodiment of the present invention. As shown in FIG. 1, a hydraulic circuit of the crane turning control device according to the present embodiment includes a prime mover 101 and a variable displacement hydraulic pump 3 driven by the prime mover 101.
A turning hydraulic motor 2 driven by pressure oil discharged from the variable displacement hydraulic pump 3, and a turning direction control for controlling the flow of pressure oil supplied from the variable displacement hydraulic pump 3 to the turning hydraulic motor 2. A valve 1, a pressure compensating valve 4 for controlling the pressure of the pressure oil bleed off to the tank 8 by the direction control valve 1, an operation lever 5 for inputting a turning command by an operator, and direction control of the operation amount of the operation lever 5 A pilot hydraulic source 7 for supplying pressure oil to a pilot hydraulic circuit for transmitting to the valve 1. The pressure compensating valve 4 is configured to control the pressure of the bleed-off pressure oil to a pressure equivalent to the driving pressure of the turning hydraulic motor 2 by guiding the driving pressure of the turning hydraulic motor 2.

In this embodiment, the pressure detectors 12A and 12B for detecting the inlet pressure and the outlet pressure of the turning hydraulic motor 2 and the operation direction detector 11 for detecting the operation direction of the operation lever 5 are provided. A tilt angle changing device 13 for changing the tilt angle of the variable displacement hydraulic pump 3, a pressure detector 12A,
The controller 10 outputs a signal to the tilt angle changing device 13 so as to control the discharge flow rate of the variable displacement hydraulic pump 3 based on the detection signal of 12B and the detection signal of the operation direction detector 11. Which of the pressure detectors 12A and 12B is on the inlet side or the outlet side is determined by the command turning direction of the turning hydraulic motor 2.

FIG. 2 is a block diagram showing a detailed configuration of the controller 10. As shown in FIG. As shown in FIG. 2, the controller 10 sets the flag to 1 when the operation lever 5 is operated in the direction A based on the detection signal SD from the operation direction detector 11, and operates in the direction B. If so, a flag setting unit 21 that sets the flag to −1, an adder 22 that calculates a difference signal ΔP between the detection signals PA and PB by the pressure detectors 12A and 12B, and multiplication of the difference signal ΔP and the flag. Multiplier 23 that obtains signal ΔPFK by multiplying the multiplication result by gain K to obtain signal ΔPFK
And only the high frequency component of the signal ΔPFK is extracted and the signal ΔP
A high-pass filter 25 for obtaining FKH; a switch 26 for switching the output of the signals ΔPFK and ΔPFKH from the coefficient unit 24 and the high-pass filter 25; and a difference between the signal ΔPFK or ΔPFKH and a preset flow signal Q to calculate the discharge flow rate An adder 27 outputs the signal QS to the tilt angle changing device 13. The flow signal Q is determined so as to have a constant flow rate without depending on, for example, the rotation speed N of the prime mover 101.

Then, the detection signal P
By calculating the difference ΔP between A and PB and multiplying the flag by the multiplier 23, it is possible to grasp how much load is acting on the turning hydraulic motor 2 in the turning direction. By multiplying by the gain K, the increase / decrease amount ΔPFK or Δ of the discharge flow rate of the variable displacement hydraulic pump 3 is calculated.
By setting PFKH and subtracting it from the preset flow rate signal Q, the next discharge flow rate can be set.

Here, the high-pass filter 25 operates as follows. For example, when a steady load is likely to occur due to the influence of a slope or wind, the switch 26 is switched,
By subjecting the signal ΔPFK from the coefficient unit 24 to high-pass filtering, it is possible to remove the influence of the steady load, thereby controlling the discharge amount based only on the signals detected by the pressure detectors 12A and 12B. It can be carried out.

Here, the relationship between the swing of the suspended load 66 and the pressure of the turning hydraulic motor 2 will be described. FIG. 3 is a diagram for explaining the relationship between the swing of the suspended load 66 and the pressure of the turning hydraulic motor 2.

The turning body 62 is connected to the turning hydraulic motor 2 via a speed reducer (not shown), and the rotating torque of the turning body 62 is generated by the turning hydraulic motor 2. Conversely, a disturbance (external load) acting on the swing body 62 acts on the swing hydraulic motor 2. That is, the revolving superstructure 62 holds the suspended load 6
Due to the swing of 6, the suspended load 66 receives a force in the swing direction. The force acting on the revolving structure in the revolving direction due to the load swing is represented by M: suspended mass, g: gravitational acceleration, at the sheave 64 (which can be approximated to the fulcrum of the pendulum).
θ: Assuming the swing angle of the suspended load, F = M × g × tan θ (1) Therefore, the force F acting on the sheave 64 can be expressed by the swing mass θ of the suspended mass 66 and the suspended mass 66 from Expression (1).

X is the swing width of the suspended load 66, L is the length of the wire rope, and the length L of the wire rope is
Assuming that L is very large (L >> X) with respect to the swing width X, tan θ ≒ sin θ ≒ X / L (2) can be regarded as: F = M × g × X / L ... (3) That is, according to the equation (3), the force F acting on the sheave 64 can be represented by the suspended mass M, the length L of the wire rope, and the swing width X of the suspended load 66.

A force F acting on the sheave 64 has a work radius R
By multiplying L and the reduction ratio α, the torque to the turning hydraulic motor 2 can be converted as shown in Expression (4). T = F × RL × α (4) Further, the torque of the turning hydraulic motor 2 is changed by one rotation of the pressure difference ΔP0 between the outlet side and the inlet side of the turning hydraulic motor 2. In general, T = ΔP0 × Q0 / (2 × π) (5) When the displacement Q0 of the turning hydraulic motor 2 is constant, the torque T becomes , The pressure difference ΔP0 between the outlet side and the inlet side of the turning hydraulic motor 2. Equation (1),
From (4) and (5), tan θ = (ΔP0 × Q0) / (2π × M × g × RL × α) (6) is derived, and the pressure on the inlet side of the hydraulic motor 2 for turning and the outlet are obtained. Side pressure, suspended mass M, working radius RL, and reduction ratio α
Is known, the state θ of the shake can be grasped. in this case,
The capacity Q0 is constant. Further, if the length L of the wire rope is known, the swing width X of the suspended load 66 can be grasped.

FIGS. 4A and 4B show the turning direction and the suspended load 66. FIG.
It is a figure showing the state of. As shown in FIG.
When the swing body 62 rotates in the direction A by the operation in the direction A, the pressure on the inlet side of the hydraulic motor 2 for swing is detected by the pressure detector 12A, and the outlet of the hydraulic motor 2 for swing is detected by the pressure detector 12B. Side pressure is detected. Then, as shown in FIG. 4A, when the movement of the suspended load 66 is delayed with respect to the swing of the swing body 62, the pressure on the inlet side of the hydraulic motor 2 for swing becomes larger than the outlet side, and conversely. FIG.
As shown in (b), when the movement of the suspended load 66 precedes, the pressure on the inlet side becomes smaller than that on the outlet side. Therefore, in the case shown in FIG. 4A, the difference ΔP calculated by the adder 22 is a positive value, and in the case shown in FIG. 4B, it is a negative value.

Next, the operation of this embodiment will be described. Assuming that the operation lever 5 is operated in the direction A by the operator, the operation direction detector 11 detects the operation of the operation lever 5 in the direction A, and the flag setting section 21
The flag is set to 1. Further, the difference signal ΔP between the detection signals PA and PB of the pressure detectors 12A and 12B is calculated in the adder 22, and the multiplier 23 multiplies the difference signal ΔP by the flag to obtain the signal ΔPF.
Then, the signal ΔPF is multiplied by the gain K in the coefficient unit 24 to obtain the signal ΔPFK. Here, when the work is being performed on a slope, the switch 26 has been switched to the B side, and the high-pass filter 25 performs high-pass filtering of the signal ΔPFK, and the signal ΔPF
KH is obtained. When the work is performed on a flat ground or the like, the switch 26 is switched to the A side. Then, the flow signal Q and the signal ΔPFK or Δ
The difference from PFKH is obtained, and a signal QS representing the next discharge flow rate is obtained. Then, the signal QS is input to the tilt angle changing device 13, and the discharge flow rate of the variable displacement hydraulic pump 3 is controlled.

Here, in the state shown in FIG. 4A, the signal ΔP obtained by the adder 22 is positive, so that the signal ΔPFK or ΔPFKH is positive.
Therefore, since the signal QS representing the next discharge flow rate obtained by the adder 27 is smaller than the flow rate signal Q, the tilt angle of the variable displacement hydraulic pump 3 is controlled by the tilt angle changing device 13 to be small. You. Therefore, the turning speed is reduced so as to follow the delay of the suspended load 66, and the swing of the suspended load 66 is prevented.

On the other hand, in the state as shown in FIG. 4B, since the signal ΔP obtained by the adder 22 is negative, the signal ΔPFK or ΔPFKH is negative. Therefore, since the signal QS indicating the next discharge flow rate obtained by the adder 27 is larger than the flow rate signal Q, the tilt angle of the variable displacement hydraulic pump 3 is controlled by the tilt angle changing device 13 to be large. You. Therefore, the turning speed is increased so as to follow the leading of the suspended load 66, and the swing of the suspended load 66 is prevented.

FIGS. 5A to 5D are diagrams showing the relationship between the discharge amount of the variable displacement hydraulic pump due to the swing of the suspended load 66, the inflow amount to the swing hydraulic motor, and the swing speed. FIG. 5 (a)
As shown in (d), when the load of the turning hydraulic motor 2 fluctuates, the flow rate of the variable displacement hydraulic pump 3 changes so as to cancel the load, and accordingly, the turning hydraulic motor 2
The flow rate into the tank also changes. As a result, the revolving speed of the revolving structure changes in a direction in which the swing of the suspended load 66 is reduced, whereby the swing of the suspended load 66 is prevented.

It should be noted that the difference signal ΔP between the signals detected by the pressure detectors 12A and 12B is zero when the deflection of the load is settled. The revolving body turns according to the turning speed.

As described above, in the present embodiment, the load acting on the turning hydraulic motor 2 and the operation direction of the operation lever 5 are detected, and the swing of the suspended load 66 is suppressed based on the detection result. As a result, the turning can be performed at the turning speed commanded by the operator irrespective of the load pressure by the pressure compensating valve 4, and the load can be prevented from swinging. This eliminates the need for the operator to perform an operation for suppressing the swing of the suspended load 66, reduces the operator's labor, and does not require skilled skills, so that the operability of crane turning can be improved. In addition, since the speed of the revolving superstructure is changed in order to prevent the load swing, the operator can easily recognize the load swing. Furthermore, since the load fluctuation can be prevented by using a function indispensable for the variable pump, that is, changing the discharge flow rate of the variable displacement hydraulic pump 3, the configuration of the apparatus is simplified, and it is preferable from the viewpoint of safety.

In the above embodiment, the suspended load 6
The pressure detectors 12A and 12B for detecting the inlet side pressure and the outlet side pressure of the hydraulic motor for turning 2 are used as means for detecting the runout of the swing 6, but the swing angle of the rope is detected at the tip of the boom 63. The swing of the suspended load 66 may be detected by providing an angle sensor that detects the swing angle of the rope with the angle sensor. Further, in the above embodiment, the work radius at the time of load deflection is not taken into consideration, but by taking into account the work radius as shown in the above equation (6), load deflection can be further prevented. .

In the correspondence between the above embodiment and the claims, the operating lever 5 is an operating means, the operating direction detector 11 is an operating direction detecting means, the pressure detectors 12A and 12B are load state detecting means, and the controller is a controller. The control device 10 and the tilt angle changing device 13 constitute control means.

[0028]

As described in detail above, according to the present invention, the load of the turning hydraulic motor and the operating direction of the operating means are detected, and the tilt angle is changed based on the detection result to change the tilt angle. Since the swing of the load is suppressed, the swing can be performed at the swing speed commanded by the operator, and the swing of the load can be prevented. This eliminates the need for the operator to perform an operation for suppressing the swing of the suspended load, reduces the labor of the operator, and does not require a skilled skill, so that the operability of the crane turning can be improved. In addition, since the speed of the revolving superstructure is changed in order to prevent the load swing, the operator can easily recognize the load swing. Further, since the load swing can be prevented by the auxiliary configuration of changing the discharge flow rate of the variable displacement hydraulic pump, the configuration of the device is simplified, and it is preferable from the viewpoint of safety.

[Brief description of the drawings]

FIG. 1 is a hydraulic circuit diagram showing a configuration of a turning control device according to an embodiment of the present invention.

FIG. 2 is a block diagram showing a configuration of a controller.

FIG. 3 is a diagram for explaining the relationship between the swing of a suspended load and the pressure of a turning hydraulic motor.

FIG. 4 is a diagram showing a relationship between a rotation direction of a swing body and a swing of a suspended load;

FIG. 5 is a graph showing a relationship among a load of a turning hydraulic motor, a pump flow rate, a motor inflow flow rate, and a turning speed.

FIG. 6 is a diagram showing a configuration of a crane.

FIG. 7 is a hydraulic circuit diagram showing a configuration of a conventional turning control device.

[Explanation of symbols]

 DESCRIPTION OF REFERENCE NUMERALS 1 turning direction control valve 2 turning hydraulic motor 3 variable displacement hydraulic pump 4 pressure compensating valve 5 operating lever 7 pilot hydraulic source 10 controller 11 operating direction detectors 12A, 12B pressure detector 13 tilt angle changing device 21 flag set section 22, 27 adder 23 multiplier 24 coefficient unit 25 high-pass filter 26 switch 61 traveling body 62 revolving body 63 boom 64 sheave 65 hook 66 suspended load 101 prime mover

Claims (1)

[Claims] 1. A variable displacement hydraulic pump, a swing hydraulic motor that drives a swing body with pressure oil discharged from the variable displacement hydraulic pump, and a pressure supplied to the swing hydraulic motor from the variable displacement hydraulic pump. A turning direction control valve for controlling the direction of oil, a pressure compensating valve for setting the pressure of a bleed-off circuit communicating from the turning direction control valve to the tank to a pressure corresponding to the driving pressure of the turning hydraulic motor, In a turning control device for a crane provided with operating means for switching the turning direction control valve, an operating direction detecting means for detecting an operating direction of the operating means, and a load state detecting for detecting a load state of the turning hydraulic motor. Means, and a load swing state in which the suspended load lags behind the swing of the swing body is detected based on signals from the operation direction detecting means and the load state detecting means. Control the tilt angle of the variable displacement hydraulic pump so as to increase the discharge flow rate when the load flow rate is reduced, and when the load swing state in which the suspended load is moving ahead of the revolving structure is detected. A turning control device for a crane, comprising: a control unit.