JPH0441395A - Turn control device for crane etc. - Google Patents

Abstract

PURPOSE:To make a turning body stop precisely at a fixed target stopping position by providing a position detective means of the turning body, a turning speed detective means thereof, and a stop position setting means thereof, and controlling the set flow quantity of a flow control valve with pressure compensation so that a discharged flow quantity from a hydraulic motor may become a target discharged flow quantity. CONSTITUTION:Detective signals of respective detectors 81-87 for a boom length, a boom angle, a load pressure of a boom hoisting cylinder, an overhang condition of outrigger, a turning angle of a turning body 104, the length of a hoisting rope, a rotational speed of a turning motor 6 are input in a controller 8, and various kinds of controls are carried out on the basis of the detective signals thereof. When automatic stop of the turning body is required, the set flow quantity of a flow quantity control valve 53 with pressure compensation is controlled to make a precise control so that an angular speed of the turning body 104 may become a target speed decreasing angular speed. As a result, the turning body 104 stops precisely at its target stop position. Also, there is no need of installing a pressure sensor, and a calculating machine, or the like of inertia moment and a stop torque, and simplification of control circuit, elevation of control responsiveness, less error and elevation of precise control can be realized.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a swing control device for a hydraulic excavator, a crane, etc., for turning and automatically stopping a swinging body using a hydraulic motor.

[Conventional technology]

Conventionally, the following devices are known as devices for automatically stopping a revolving structure.

■ Japanese Patent Application Laid-Open No. 62-31703 discloses that in a hydraulic excavator, the stopping torque T (k
gf-m) using the following formula, ΔP φ q T = ... (1) 200 ・π ΔP: Differential pressure between motor suction side and discharge side (kgf/cm)
q: Motor capacity (cc/rev) Also, stopping torque T (kgf-m) and moment of inertia I
(kgf-m-82) is calculated using the following formula, d ω T=I
... (2) dt d ω : Turning angular acceleration (rad/s2) dt When the rotating body automatically stops, the relational expression between the stopping torque T and the moment of inertia I from the above equation (2), T d
ω... (3) A method has been disclosed in which the stopping torque T is controlled according to the magnitude of the moment of inertia I of the rotating body so that I dt is constant. For control purposes, this device is equipped with a variable relief valve at the entrance and exit of the hydraulic motor that drives the rotating structure, and when the rotating structure automatically stops, the supply of pressure oil from the hydraulic pump to the hydraulic motor is stopped, and the moment of inertia I The set pressure of the variable relief valve is controlled according to the magnitude of the pressure, and the pressure on the motor discharge side is controlled.

◎ Japanese Patent Application Laid-Open No. 62-153090 describes a method for supplying pressure oil from a hydraulic pump to a hydraulic motor that drives a rotating body in order to automatically stop the rotating body before the rotating body reaches the limit value of the safety area in a hydraulic crane. A deceleration area is set before the limit value of the above-mentioned safe area, and when the rotating body enters the deceleration area, the spool stroke of the electric proportional control valve is controlled to control the hydraulic motor. A method is disclosed in which the inflow flow rate to the inlet is controlled.

[theta] Utility Model Application Publication No. 2-18485 discloses a system in which the oil discharged from the motor is unloaded and the pressure on the discharge side of the motor is controlled by an electromagnetic proportional pressure control valve when turning is automatically stopped.

[Problem to be solved by the invention]

In the above-mentioned conventional technology, it is necessary to detect or calculate both the moment of inertia (2) and the stopping torque T for control. In particular, when applying this to a hydraulic crane, the stopping torque T is determined by the following equation (1)7 or (2)'.

Δp-q I T-× io × ... (1)'20
0 π ηM ΔP η M: Differential pressure between motor inlet side and outlet side (kgl/cffl)
, motor capacity (cc/++v) Absolute reduction ratio of swing power transmission system: total mechanical efficiency dω and dω.

T=　I　w +I.

... (2)' dt dt Iw Moment of inertia of suspended load (kgf-m-82) dω
7 Angular acceleration of suspended load (ad/s2) dt Ic: Moment of inertia of rotating body (lCgf-m-52)
dω.

: Angular acceleration of the rotating body Crad / s 2) dt As is clear from equation (2) 7 above, when controlling the stopping torque T in a crane, the suspended load suspended by the hoisting rope is different from the rotating body. Because of the different movements, it is necessary to calculate not only the moment of inertia IC of the rotating body but also the moment of inertia of the suspended load, and it is necessary to measure the angular acceleration of the crane and the angular acceleration of the suspended load. Also, above (
1) In order to determine the differential pressure ΔP, a pressure sensor on the inlet side of the motor, a pressure sensor on the outlet side, and means for calculating the differential pressure are required. This increases the number of sensors and computing units, complicates the control circuit, and increases costs. Further, there are other problems such as time-consuming calculations and control, poor responsiveness, easy errors, and poor control accuracy.

On the other hand, in the conventional technology ◎, the main control valve for the swing is configured with an electric proportional control valve. The relationship between , pressure, and flow rate is expressed by the following general formula.

Q: Flow rate (inflow flow rate to the motor) (//m1n) C: Constant A: Valve opening area (cd) g: Gravitational acceleration (980 an/s 2) ΔPv: Differential pressure before and after the valve (Icgt /a+f) γ : Specific weight of fluid (
kg f /ctj) In this prior art ◎, even if the valve opening (opening area) A of the electric proportional control valve is held at a predetermined control value to control the inflow flow rate Q to the motor, the motor inflow side If the pressure p changes, the inflow flow rate Q to the motor and the discharge flow rate, that is, the speed of deceleration, will also change. Therefore, it is difficult to control the speed of deceleration of the motor in a preset pattern. Therefore, feedback control is required, but during this feedback control, even if the valve opening area is properly controlled as described above, if the turning moment of inertia changes, the braking torque, that is, the braking pressure will also change, and the braking pressure will change. The amount of feedback (deviation) increases due to the change in the inflow flow rate, making it necessary to control and change the valve opening area significantly, resulting in a lack of control accuracy, and the stopping position of the rotating body may deviate from the target stopping position. There is a risk that the suspended load may remain shaken when the swing stops.

In addition, the swing control method includes a neutral brake method that blocks the oil passages on both sides of the swing hydraulic motor to stop the swing when the swing direction switching valve is returned to neutral, and a neutral brake system that blocks the oil passages on both sides of the hydraulic motor for turning to stop the swing. There is a neutral-free type in which the motor is connected to the motor and rotated by inertia to perform swing flow operation, but in both of the above conventional technologies ■◎, when the swing automatically stops, the oil flow to the motor is cut off, and the braking is performed. In order to control
It is necessary to use a swing direction switching valve in the neutral block, and it can only be applied to machines with a neutral brake system.

In addition, according to prior art O, which can be applied to both the neutral brake system and the neutral pretend system, it unloads or onloads the discharge pressure of the pump and variably controls the pressure on the discharge side of the motor. Since it is basically pressure control, it is necessary to control it in accordance with the turning moment of inertia.

Therefore, if the working conditions of the crane (for example, the boom angle) change, it is necessary to recalculate the moment of inertia and change the control signal each time, which results in a long control calculation time (and makes it difficult to improve responsiveness). Improvement in this point was desired.

In view of these circumstances, the present invention provides a system that allows the swing control valve to remain switched to the swing position when it becomes necessary to automatically stop the swing structure, such as before the swing structure reaches a dangerous area during swing work. In addition, regardless of the magnitude of the swinging inertia moment, the swinging body can be automatically stopped at the target stop position, and the swinging inertia moment and stopping torque can be calculated, as well as pressure sensors and calculations for the calculation. It is possible to simplify the control circuit by eliminating the need for equipment, improve control accuracy, and automatically stop the rotating body accurately and smoothly at the target stop position without leaving any swings in the suspended load. It is an object of the present invention to provide a swing control device for a crane or the like that can be effectively used in both a neutral brake type and a neutral pretend type.

[Means to solve the problem]

The present invention provides a swing control device that includes a hydraulic pump, a rotating body, a hydraulic motor that drives the rotating body, and a swing control valve that controls supply and discharge of pressure oil from the hydraulic pump to the hydraulic motor. a pressure-compensated flow control valve for controlling the discharge flow rate from the motor; a position detection means for detecting the position of the rotating body; and a speed detection means for detecting the rotation speed of the rotating body;
Stop position setting means for setting a target stop position of the rotating body;
Start of deceleration necessary to stop the rotating body at the target stop position based on the position and rotation speed of the rotating body detected by the position detecting means and speed detecting means and the target stop position set in the stop position setting means. a calculation means for calculating a point, a target deceleration speed, and a target discharge flow rate from the hydraulic motor corresponding to the target deceleration speed, and when the rotating body turns from the deceleration start point to the target stop position based on the calculation value by the calculation means. The apparatus is characterized in that a set flow rate control means is provided for controlling the set flow rate of the flow rate control valve with pressure compensation so that the discharge flow rate from the hydraulic motor becomes a target discharge flow rate.

In addition, in this configuration, the set flow rate control means is configured to control when the rotating speed of the rotating structure detected by the speed detection means is larger than the target deceleration speed when the rotating structure turns from the deceleration start point to the target stop position side. Outputs a control signal that sets the set flow rate of the flow control valve with pressure compensation as the target discharge flow rate,
At other times, the control signal is configured to output a control signal that makes the set flow rate equal to or higher than the maximum discharge flow rate of the hydraulic motor.

[For production]

With the above configuration, when the rotating body turns from the deceleration start point toward the target stop position, the set flow rate of the flow rate control valve with pressure compensation is controlled by the signal from the set flow rate control means, and the discharge flow rate from the motor is controlled. The motor is decelerated at the target deceleration speed, and the rotating body is automatically decelerated and stopped at the target stop position. In particular, since the flow rate control valve with pressure compensation controls the discharge flow rate from the motor to control the deceleration speed of the rotation, regardless of the pressure on either the inlet side or the outlet side of the motor,
Accurate speed control is possible. Therefore, there is no need to provide a pressure sensor or a moment of inertia calculator, and the control circuit can be simplified, responsiveness can be improved, errors can be reduced, and control accuracy can be increased. Then, the revolving body can be accurately stopped at a predetermined target stop position without leaving any swinging of the suspended load.

Note that the discharge flow rate from the motor to the tank is determined by the smaller of the set flow rate of the pressure compensated flow control valve and the flow rate on the meter-out side of the swing control valve.
Even if the swing control valve remains operated to the swing position, the above-mentioned automatic stop control of the swing is performed properly, and during the automatic stop control, the operator manually operates the swing control valve to stop the swing. It is also possible to make an emergency stop by controlling the deceleration speed of the motor, that is, the rotating body, using a control valve.
Safety is increased. Furthermore, whether the swing control valve is a neutral brake type or a neutral-flip type, automatic stopping of the swing is properly performed.

Further, according to the structure of claim 2, when the automatic stop control is not performed, such as during normal turning work and when the operator performs manual operation for an emergency stop as described above even during the automatic stop control, the pressure is reduced. By setting the flow rate of the compensated flow control valve to the maximum, the pressure compensated flow control valve does not interfere with normal turning work and emergency stop work, and each work can be performed smoothly.

〔Example〕

An example of a crane to which the present invention is applied is shown in FIG. This crane 100 includes a rotating body 104 that can be rotated around a vertical rotation center 103 via a hydraulic swing motor 6 and a rotation deceleration unit 67 on a traveling body 102 equipped with an outrigger 101. A boom 107, which is extendable and retractable, is supported via a boom hoisting cylinder 106 so as to be able to rise and fall about a boom foot pin 105. Tip of boom 107 (boom point sheave)
A hoisting rope 108 is suspended from the hoisting rope 1.
At 08, the hanging load 109 is hoisted and lowered. In this crane 100, the following swing control device is provided to perform swing control.

FIG. 1 is a hydraulic circuit diagram showing an embodiment of the present invention. Note that the present invention can be effectively applied to both a neutral brake system and a neutral brake system. For convenience of explanation, this embodiment will be described below by taking as an example a case in which it is applied to a circuit that can be switched between a neutral brake system and a neutral brake system.

In FIG. 1, 1 is a hydraulic pump, 2 is a selection valve, 3 is a swing direction switching valve, 6 is a swing hydraulic motor, 7 is a tank,
8 indicates a controller. The selection valve 2 is an electromagnetic switching valve, and a check valve 14.1 is connected in parallel to the discharge oil passage 10 of the pump 1 in response to a signal from the controller 8.
1st with 5.16. Second. Third branch oil passages 11.
12.13 and the corresponding intermediate oil passages 21, 22.
23 are selectively switched to a position 2a (neutral brake mode) in which they communicate with each other individually, and a position 2b (neutral free mode) in which they all communicate with each other. Note that the selection valve 2 may be a manual type or a hydraulic pilot type.

The swing direction switching valve 3 normally has an 8 that is switched from a neutral position to each swing position 3a, 3b by an operating lever 30.
A three-position switching valve is used.

Note that 3a' and 3b' indicate transition positions. The first directional control valve 3. Second. Each intermediate oil passage 21, 22, 23 is connected to each of the third boats 31, 32, 33, and the fourth. 5th each boat 34. ．． The motor side oil passages 41 and 42 are connected to the sixth. 7th. 8th each boat 36, 37.38
A return oil passage 72 to the tank 7 is connected to the tank 7 via a bleed-off oil passage 71. Reference numerals 43 and 44 denote bypass oil passages, which are equipped with check valves 45 and 46. The selection valve 2, the directional control valve 3, and each check valve 14, 15°1
6.45.46 constitute a swing control valve. 1
7 is a main relief valve, and 73 is a back pressure valve.

The oil passage between the directional control valve 3 and the motor 6, that is, between the oil passages 41 and 61 and between the oil passages 42 and 62,
Check valves 51 and 52 each allow oil to flow from the directional control valve 3 to the motor 6, and a pressure-compensated flow control valve 53 controls the discharge flow rate from the motor 6 to the directional control valve 3 side.
．． 54 are connected in parallel. The flow rate control valves 53 and 54 with pressure compensation have their set flow rates Qs controlled according to the control signal (current i) from the controller 8 as shown in FIG.

A rotating body 104 (see FIG. 3) is connected to the motor 6 via a rotating deceleration unit 67. 63 and 64 are overload relief valves, and 65 and 66 are anti-cavitation check valves.

81 is a boom length detector, 82 is a boom angle detector, 8
3 is a load pressure detector of the boom hoisting cylinder 106, 84
85 indicates the overhanging state detector of the outrigger 101, and 85 indicates the rotation angle detector of the rotating body 104, and each of these detectors 81-
The detector 85 of the overload prevention device installed in the crane 100 shown in FIG. 3 is used as is. Reference numeral 86 indicates a length detector of the hoisting rope 108, and reference numeral 87 indicates a rotation speed detector of the swing motor 6.

In FIG. 1, with the selection valve 2 held at the illustrated position 2a (neutral brake mode), when the lever 30 is operated in the direction of arrow A and the directional control valve 3 is switched to the swing position 3a, the directional control valve At the transient position 3a' of 3, the pump 1
Of the discharged oil, the flow rate Q^ corresponding to the spool stroke of the directional control valve 3 flows through the boat 32.35 in the convex direction of the arrow, flows into the motor 6, and the excess oil flows into the boat of the directional control valve 3. From 33, the water is bled off through the spool notch, boat 38, flows in the direction of the arrow 2, and is returned to the tank 7. Then, the motor 6 is rotated forward at a speed corresponding to the inflow flow rate QA, and the rotating body 104 is rotated, for example, clockwise via the rotation deceleration unit 67.

At this time, during normal turning work, the flow control valve with pressure compensation 53
Since the control current i is set to the maximum value and the direction valve 53 is fully opened, the discharged oil from the motor 6 flows in the direction of the arrow and the direction of the flow control valve 53 with pressure compensation and the direction changeover valve 3 to the tank 7. will be returned to.

During this turning acceleration, detection signals from each of the detectors 81 to 87 are input to the controller 8, and the following control is performed based on these detection signals.

FIG. 2 shows a block diagram of control by the controller 8. In FIG. 2, the working radius calculation means 91 calculates the boom length LB (m) and boom angle α (degrees) detected by the boom length detector 81 and the boom angle detector 82;
Based on the distance RA (m) from the boom foot pin 105 to the turning center 103, the working radius Rw (
m).

Ry=LB cosα-RA The lifting load calculation means 92 calculates the working radius Rw, the boom length B, and the load pressure of the boom hoisting cylinder 106 detected by the cylinder pressure detector 87, that is, the pressure on the head side P W 1 (kg f / car) and the pressure on the rod side P W 2 (kg f / a),
The lifting load W (kgf) during the work is calculated.

The rated load calculation means 121 calculates the boom length LB, the working radius Rw, and the overhang state (extension amount) of each outrigger 101 detected by the IJ gas condition detector 84 OR(
m) and the rated load data stored in the rated load memory 120, the rated load w0 (kgf) of the crane 100 in the current working state is calculated.

The load factor calculation means 122 calculates the above-mentioned rated load W. Calculate the load ratio W/W O of the actual lifting load W. The work stop control means 123 activates an alarm when the load ratio W/Wo reaches 90% or more, and when it reaches 100% or more, operates the crane in a dangerous manner except for swinging, that is, extends the boom 106. , outputs a signal to each actuator to forcibly stop the lodging, hoisting of the suspended load 109, etc.

On the other hand, the target stop position setting means 93 for the rotating body determines the boom length LB, the lifting load W, and the outrigger extended state O.
Based on ) and set this as the target stopping position.

The allowable turning angle calculating means 94 calculates the above-mentioned limit turning angle θmax.
, the working radius RW of the suspended load 109, and the turning angle detector 85.
Based on the current turning angle θ detected by , the allowable turning angle, that is, the remaining turning angle θ from the current position C□ of the rotating body 104 to the limit turning angle θmal. (“ad)” is calculated.

θ. θma
'(xd/s) is calculated.

NM 1 ω= × ×2 π
(5) to 60 io: Edge speed ratio of swing power transmission system Note that the rotational speed NM of the motor 6 is expressed by the following equation.

Q Efficiency (if the pressure is low, ηy−1,0) Therefore, the turning angular velocity ω can be calculated using the above equation (6) as (5)
By substituting into the formula, it can be obtained using the following formula.

1007rQ (7) 3 io ηMQ Here, both the rotating body 104 and the hanging load 109 are ω as shown by the solid line ■ and the broken line ■ in FIG.

If the rotating body 104 is decelerated at a constant angular acceleration as shown by the solid line ■ in the same figure from the state in which the suspended load 109 is rotating at an angular velocity of (rad/s) without swinging, the rotating body 104 will be
. After (sec), the suspended load 109 stops and the angular acceleration changes as shown by the broken line ■ in the same figure, after which time t. It has been found that the boom point is located directly below the boom point and stops without any vibration remaining.

At this time, the angular acceleration of the rotating body indicated by the solid line (■), the angular velocity ω (=ωC), and the time t. The turning angle θr between is determined by the following equation.

dωC ω　O ... (8) it t.

ω　0 ωC=　ω　0− ... (9) t.

ω　0 θ　r=ω. t- ...(10) 2t.

However, l (m) is the length of the hoisting rope 108, that is, the distance from the center of the boom point sheave to the center of gravity of the suspended load, and g (m/s2) is the gravitational acceleration.

Therefore, based on the hoisting rope length l detected by the rope length detector 86, the deceleration time calculation means 96 uses the above equation (11) to automatically move the revolving structure 104 without leaving any swing of the suspended load 109. Time required to stop t. Calculate.

The deceleration angle calculating means 97 converts the current angular velocity ω of the rotating body 104 calculated by the turning speed calculating means 95 into the angular velocity ω before deceleration shown in FIG. Binding, its angular velocity ω. and the above deceleration time t
. Based on this, the turning angle required from the start of braking until the rotating body 104 stops when decelerating in the time given by the above equation (11), that is, the deceleration angle 1θr1, is expressed as (10)
Calculate using the formula.

The margin angle calculation means 98 calculates the angle of rotation of the rotating body 1 before starting deceleration.
The angle at which 04 can turn at the current angular velocity ω, that is, the margin angle Δθ is calculated.

Δθ=θC−θr The target angular velocity setting means 110 uses the margin angle Δθ and the current angular velocity ω calculated by the turning speed calculating means 95,
The angular velocity ω when the margin angle Δθ becomes 0 is the angular velocity ω before deceleration. Then, the angular velocity ωC required to decelerate with uniform angular acceleration according to the above equations (8) and (9) is calculated, and this is set as the target deceleration angular velocity ω9. In addition,
When the margin angle Δθ is greater than 0, the target angular velocity setting means 110 outputs a signal that makes automatic stop control unnecessary. Further, when the margin angle Δθ is less than 0, the alarm means 116 issues an alarm to notify the operator etc. that automatic turning stop control will be started.

The target discharge flow rate calculation means 112 calculates the target discharge flow rate Q on the motor discharge side necessary for decelerating and stopping the motor 6 based on the angular velocity control signal inputted from the target angular velocity setting means 110 via the comparison means 111. Calculate. This target discharge flow rate Qo is the flow rate Q. The relational expression Q between and the angular velocity ω.

= f1 (ω), and the relational expression ω between angular velocity ω and time t
= f2 (t), that is, determined by the above equations (7) and (9).

The control current calculation means 113 sets the set flow rate Qs of the pressure compensated flow control valve 53 or 54 on the motor discharge side to the target discharge flow rate Q. The control current i required to control the current is calculated. This control current i is a current i and a flow rate Q. The relational expression 1=f3(
Qo).

In this way, while the rotating body 104 is turning, if the rotating body 104 is in the safe area and there is no need for automatic stopping, that is, if the margin angle Δθ calculated by the margin angle calculation means 98 is larger than 0, the control current calculation means The signal i outputted from 113 becomes the maximum value (for example, 700 mA), and the set flow rate Q8 of the pressure compensated flow control valve 53 on the motor discharge side becomes the maximum value QmaX (see FIG. 5), that is, the fully open state. Therefore, the discharge flow rate QB from the motor 6 is not subjected to the flow rate control action, that is, the deceleration action, by the pressure compensated flow rate control valve 53, and the motor 6, that is, the rotating body 104, is controlled by the inflow flow rate QA determined by the spool stroke of the directional control valve 3. The rotation is accelerated smoothly at a corresponding rotation speed and at a pressure (acceleration pressure) corresponding to the load by the rotating body 104 and the like.

Next, when it becomes necessary to automatically stop the rotating body 104, that is, when the rotating body 104 turns from the deceleration start point C2 to the target stop position C3 side in FIG. A control signal i of a predetermined deceleration pattern is output from the calculation means 113 to the pressure compensated flow control valve 53 on the discharge side of the motor 6, and the set flow rate Q8 of the pressure compensated flow control valve 53 is determined by the signal i as shown in FIG. It is controlled as shown in . Accordingly, the flow rate QB on the motor discharge side corresponds to the set flow rate Qs, that is, the target discharge flow rate Q. The angular velocity ω of the rotating body 104 is controlled to the target deceleration angular velocity ω shown by the solid line ■ in FIG. It is controlled so that

Furthermore, during this control, the target deceleration angular velocity ω set in the target deceleration speed setting means 110 is determined by the deviation calculation means 114.
The deviation Δω (=ω9−ω) between A and the current turning angular velocity ω calculated by the turning angular velocity calculating means 95 is calculated, and the feedback signal calculating means 115 multiplies the deviation Δω by a gain K to calculate a feedback signal. The signal is fed back to the comparison means 111, and the control signal 11 sets the flow rate, that is, the motor discharge flow rate Q.

is controlled by feedback. Then, the angular velocity ω of the rotating body 104 is accurately controlled to become the target deceleration angular velocity ω9. As a result, the hanging load 109 does not waver,
The revolving body 104 is automatically stopped accurately at the target stop position (Ca in FIG. 4).

In addition, in the above control, the flow rate control valve with pressure compensation 53
The discharge flow rate of motor 6 is Q. Therefore, the directional control valve 3 can be moved to the swing position 3a side regardless of the flow rate QA and pressure (acceleration pressure) on the inflow side of the motor 6, and without being affected by the moment of inertia of the crane or suspended load. Even if the switching remains, the above discharge flow rate Qo and the rotating body 10
The angular velocity ω (=ωC) for deceleration of No. 4 is accurately controlled.

In addition, since the deceleration speed is controlled by controlling the discharge flow rate Qo of the motor 6 regardless of the braking pressure (stopping torque), the deceleration speed is controlled by controlling the discharge flow rate Qo of the motor 6. There is no need to calculate the moment of inertia IW of 109 each time, and there is no need to detect the pressure on the inlet side and the pressure on the outlet side of the motor 6 each time, which reduces the number of sensors and calculators installed, and reduces costs. I can figure it out.

Next, during the automatic stop control of the swing, when the directional control valve 3 is returned from the swing position 3a to the neutral direction by operating the lever, the discharged oil guided in the direction of the arrow from the motor 6 is discharged at the transition position 3a'. Tank 7 via directional valve 3
When the fluid is discharged, its flow rate is throttled by the spool throttle on the meter-out side of the directional control valve 3. At this time, part of the discharged oil from the motor 6 also flows into the bypass passage 43 from the passage 41, but since the selection valve 2 is in the illustrated position 2a in this neutral brake mode, the oil discharged from the motor 6 flowing into the bypass passage 43 is The drained oil is blocked by the check valve 14. Therefore, there is only one passage leading from the boat 34 to the boat 36 on the meter-out side, and as the directional control valve 3 is returned from the swing position 3a to the transition position 3a', the oil discharged from the motor 6 is throttled by the throttle on the meter-out side. It is returned to tank 7 while being washed away.

Here, the discharge flow rate from the motor 6 to the tank 7 is the set flow rate Q of the flow rate control valve 53 with pressure compensation. The flow rate is controlled by the smaller of the flow rate controlled by the lever 30 and the flow rate controlled by the directional control valve 3. Therefore, during the control of the automatic swing stop, for example, if the operator notices a danger, the lever 30
When the motor is returned to the neutral position and the meter-out side of the directional control valve 3 is throttled, the discharge flow rate Qo from the motor 6 is controlled by the meter-out side of the directional control valve 3, and the system automatically stops as shown by the arrow ■ in Fig. 6. The motor 6, that is, the rotating body 104, is decelerated at an angular velocity ωX that is smaller than the target deceleration angular velocity ω9 for the rotation, so that priority is given to manual operation, and the operator can intervene in the control even during automatic control, making it possible to make an emergency stop.

Note that during this manual operation, the angular velocity ω(
=ωX) is smaller than the target angular velocity ω9, the deviation Δω (=ωA−ω) obtained by the comparison means 114 is positive. In this case, the control signal i output from the control current calculation means 113 becomes a large value in an attempt to increase the flow rate, and the pressure compensated flow control valve 53 no longer performs the flow control function, and this valve 53 requires manual operation intervention. interference is prevented.

Next, with the selection valve 24 in FIG.
When switching to the side, the motor 6 is rotated and accelerated by substantially the same effect as during turning acceleration in the neutral brake mode, and the rotating body 104 is turned.

Here, if the rotating body 104 is in the safe area, the set flow rate Qs of the pressure compensated flow rate control valve 53 is maintained at the maximum value as described above, and no deceleration effect is exerted.

Thereafter, when the directional control valve 3 is returned from the swing position 3a to the neutral direction, the discharged oil from the motor 6 flows from the boat 34 to the tank 7 via the boat 36 at the meter-out side at the transition position 3a' of the directional control valve 3. When the oil is discharged, it is throttled by the throttle of the spool, but at this time, a part of the discharged oil flows in the direction of the arrow, flows into the boat 33 via the bypass oil passage 43 and the seat 1f2b of the selection valve 2, and then flows into the boat 37. It flows out into tank 7 through . Therefore, even if the directional control valve 3 is returned from the swing position 3a to the transition position 3a', the meter-out side will not be throttled in total. Further, since the set flow rate Qs of the pressure compensated flow rate control valve 53 is also maintained at the maximum value, no deceleration effect is exerted. Moreover, on the inflow side of the motor 6, from the pump 1 to the port) 33, 37
The remaining discharged oil that was bled off to tank 7 through
A portion of the discharged oil from the motor 6 led to the boat 32 via the bypass oil passage 43 and the left position 2b of the selection valve 2 joins together and flows into the motor 6. As a result, the motor 6 continues to rotate due to inertia, and the rotating body 104 performs a so-called neutral flow operation.

Furthermore, when the directional control valve 3 is returned from the above-mentioned transient position W 3 a' to the neutral position, each boat 31 to 3 of the directional control valve 3
8 are all communicated at the left position 2a of the selection valve 2, the oil discharged from the pump 1 flows in the upward direction of the arrow and bleeds off to the tank 7, and no acceleration pressure is generated on the inflow side of the motor 6. However, the motor 6 continues to rotate due to inertia,
Discharged oil from the motor 6 flows into the inflow side of the motor 6 via the bypass oil path 43, the left position 2b of the selection valve 2, and the neutral position of the directional control valve 3. Therefore, the motor 6 does not stop immediately, but rotates due to inertia and performs a swirling operation, and then the revolving body 104 is gradually decelerated and stopped due to external forces such as wind and piping resistance to oil.

When an automatic stop is required during the above-mentioned swing acceleration and swing flow operation, the pressure-compensated flow control valve 53 on the motor discharge side is set by the same action as when the swing is automatically stopped in the neutral brake mode described above. The flow rate Qs is controlled,
This control valve 53 controls the discharge flow rate Q from the motor 6. is controlled, the motor 6 is decelerated, and the rotating body 104 is automatically decelerated and stopped at the target stop position.

In addition, when it is desired to quickly decelerate and stop the rotating body, that is, the motor 6, during drift operation and automatic stop control due to the inertia of the rotating body 104, the lever 30 is operated in the opposite direction to the operation direction A, that is, the reverse lever It is sufficient to operate the directional switching valve 3 to switch to the position 3b'3b side. In this case as well, manual control is given priority and the operator can intervene in the control even during automatic control, making it possible to make an emergency stop.

In the above embodiment, the pressure-compensated flow control valves 53 and 54 are provided between the motor 6 and the directional control valve 3, but the pressure-compensated flow control valves 53 and 54 are provided downstream of the directional control valve. The installation location is not particularly limited.

Furthermore, the device of the present invention can be applied to hydraulic excavators, aerial work vehicles, and other construction machines, and can be applied to both neutral brake-only types and neutral free-only types.

〔Effect of the invention〕

As described above, the present invention can automatically decelerate and stop the motor, that is, the rotating body, by controlling the discharge flow rate of the motor with a pressure-compensated flow control valve when it becomes necessary to automatically stop the rotating body during swinging work. .

In particular, since the discharge flow rate from the motor is controlled and decelerated, the speed can be accurately controlled regardless of the pressure on either the inflow side or the discharge side of the motor. Further, there is no need to provide a pressure sensor, a calculator for the moment of inertia, a stopping torque, etc., and the control circuit can be simplified, control responsiveness can be improved, errors can be reduced, and control accuracy can be increased. Then, the revolving body can be accurately stopped at a predetermined target stop position without leaving any swinging of the suspended load. Further, during the automatic stop control, the operator can intervene manually to bring the revolving structure to an emergency stop, resulting in a highly safe system. Furthermore, it has the advantage of being applicable to both the neutral brake system and the neutral-flip system.

Further, according to the device of claim 2, when the automatic stop control is not performed, such as during normal turning work and when the operator performs manual operation for an emergency stop as described above even during the automatic stop control, The set flow rate of the pressure-compensated flow control valve can be maximized, and the pressure-compensated flow control valve can perform each work smoothly without interfering with normal swing work and emergency stop work. I can do it.

[Brief explanation of the drawing]

Fig. 1 is a hydraulic circuit diagram showing an embodiment of the device of the present invention, Fig. 2 is a control block diagram of a controller, Fig. 3 is a side view showing an example of a crane to which the present invention is applied, and Fig. 4 is a revolving structure. FIG. 5 is a control characteristic diagram of the flow rate control valve with pressure compensation, and FIG. 6 is a diagram showing the relationship between angular velocity and deceleration time when the rotating body is decelerated to a stop. DESCRIPTION OF SYMBOLS 1... Hydraulic pump, 2... Selection valve, 3... Directional switching valve (swivel control valve), 6... Hydraulic motor, 7... Tank, 8... Controller, 52.53. ...Flow control valve with pressure compensation, 81...Boom length detector, 82.
... Boom angle detector, 83... Load pressure detector of the hoisting cylinder, 84... Outrigger extension state detector,
85...Turning angle detector, 86...Hoisting rope length detector, 87...Motor rotation speed detector, 93...
Target stop position setting means, 94... Allowable turning angle calculating means, 95... Turning speed calculating means, 96... Deceleration time calculating means, 97... Deceleration angle calculating means, 98... Margin angle calculating means. Means, 100...Crane, 104...
Revolving body, 109... Hanging load, 110... Target angular velocity setting means, 111... Comparison means, 112... Target discharge flow rate calculation means, 113... Control current calculation means, 114
... Deviation calculation means, 115 ... Feedback control signal calculation means. Patent applicant: Kobe Steel, Ltd. Agent
Patent Attorney Etsushi Kotani Patent Attorney Chief 1
) Masaru Patent Attorney Takao Ito

Claims (1)

[Claims] 1. Swing control comprising a hydraulic pump, a rotating body, a hydraulic motor for driving the rotating body, and a swing control valve for controlling supply and discharge of pressure oil from the hydraulic pump to the hydraulic motor. The device includes a flow control valve with pressure compensation that controls the discharge flow rate from the hydraulic motor, a position detection means that detects the position of the rotating body, a speed detection means that detects the rotation speed of the rotating body, and a target stop of the rotating body. A stop position setting means for setting the position, and a target stop of the rotating body based on the position and rotation speed of the rotating body detected by the position detection means and speed detection means and the target stop position set in the stop position setting means. A calculation means for calculating a deceleration start point and a target deceleration speed necessary for stopping at the position, and a target discharge flow rate from the hydraulic motor corresponding to the target deceleration speed, and a rotating body starts decelerating based on the calculated value by the calculation means. A set flow rate control means is provided for controlling the set flow rate of the flow rate control valve with pressure compensation so that the discharge flow rate from the hydraulic motor becomes the target discharge flow rate when turning from the point to the target stop position side. Swing control device for cranes, etc. 2. The set flow rate control means is configured to provide pressure compensation when the rotating speed of the rotating structure detected by the speed detection means is greater than the target deceleration speed when the rotating structure turns from the deceleration start point to the target stop position side. It is characterized by being configured to output a control signal that makes the set flow rate of the flow control valve a target discharge flow rate, and at other times output a control signal that makes the set flow rate equal to or higher than the maximum discharge flow rate of the hydraulic motor. A swing control device for a crane or the like according to claim 1.