JP2001328795A - Crane revolution control device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a crane revolution control device capable of relieving the shock of a revolving element as much as practicable even in the case the signal output to a solenoid-operated proportional decompression valve to control the drive of the revolving element is stopped. SOLUTION: Pipelines 6A and 6B in connection to the inlet/outlet port of a hydraulic motor 2 for revolution are connected by hydraulic selector valves 9A and 9B, and the drive of these valves 9A and 9B is controlled by the solenoid-operated proportional decompression valve 9C so that the two pipelines 6A and 6B are put in communication and shut off in conformity to the signals given from a mode selecting switch 13, pressure sensors 10A and 10B, and a rotating speed sensor 11. The hydraulic selector valve 9B is set to valve characteristics such that the pipelines 6A and 6B are in mutual communication in a minute quantity when the signal output to the decompression valve 9C is stopped due to wire severance, etc., whereby the hydraulic braking force is reduced and the shock of the revolving element 43 is relieved.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a turning control device for a construction machine such as a crane.

[0002]

2. Description of the Related Art Conventionally, a turning control system includes a method in which a motor is rotated by inertia of a revolving body when an operating lever is returned to a neutral state (referred to as a neutral free system), and a method in which the operating lever is returned to a neutral state. There is a method of stopping the rotation of the motor (referred to as a neutral brake method). It is desirable that these methods be properly used in accordance with the work content. For example, Japanese Utility Model Laid-Open Publication No. 61-112068 discloses an apparatus in which each machine can arbitrarily select each method.

In the device described in this publication, a switching valve is provided in a pair of conduits between a turning control valve of a neutral block and a hydraulic motor which can be switched in accordance with an operation amount of an operating lever, and the operating lever is set near neutral. Provide a pressure switch that turns on when returning. When the pressure switch is turned on while the neutral free state is selected, a control signal is output to the switching valve, and the switching valve is switched to communicate with the inlet / outlet port of the hydraulic motor, whereby a neutral free state is obtained. . In a state where the neutral brake is selected, the output of the control signal to the switching valve is stopped, and the switching valve is switched so as to always prevent communication of the inlet / outlet port of the hydraulic motor. Is obtained.

[0004]

However, in the device described in the above-mentioned publication, when the operating lever is returned to the vicinity of the neutral state in the state where the neutral free state is selected, the control signal to the switching valve is caused by some cause (for example, disconnection). Is stopped, the switching valve is switched so as to prevent the communication of the inlet / outlet port of the hydraulic motor. As a result, an abrupt braking force is generated in the hydraulic circuit, which gives a shock to the deceleration operation of the revolving superstructure, causing load swing and the like.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a crane turning control device capable of minimizing a shock of a revolving body even when output of a control signal to a control valve is stopped due to disconnection or the like. It is in.

[0006]

A description will be given with reference to the drawings showing an embodiment. (1) As shown in FIGS. 1 and 9, the invention of claim 1 provides a hydraulic pump 3, a turning hydraulic motor 2 driven by hydraulic oil discharged from the hydraulic pump 3, and a hydraulic motor A control valve 1 that controls the flow of pressure oil supplied to the hydraulic motor 2 and shuts off a pair of ports communicating with the inlet / outlet port of the hydraulic motor 2 when in neutral, and two pipes respectively connected to the inlet / outlet port of the hydraulic motor 2 The present invention is applied to a crane turning control device including a valve device 9 for connecting and disconnecting the roads 6A and 6B and a control unit 12 for outputting a drive command A to the valve device 9. When the valve device 9 is driven so as to open and close the two pipelines 6A and 6B in response to the drive command A from the control means 12, and the drive command A is not output from the control means 12 ( A = 0) 2 pipes 6
The two pipelines 6A and 6B are communicated with a predetermined opening area so that the hydraulic motor 2 does not stop suddenly due to the interruption between A and 6B. (2) The invention according to claim 2 is the crane turning control device according to claim 1, wherein the valve device 9 is provided in parallel between the two pipe lines 6A and 6B as shown in FIGS. The first flow control valve 9A and the second flow control valve 9B that have been set, and the first flow control valve 9A and the second flow control valve 9B
And a pilot pressure supply means 9C for supplying a pilot pressure according to a drive command from the control means 12. The first flow control valve 9A and the second flow control valve 9B are supplied from the pilot pressure supply means 9C. As the pilot pressure increases, the opening amount of the first flow control valve 9A increases, and the opening amount of the second flow control valve 9B decreases,
Further, it has such a characteristic that the maximum opening of the first flow control valve 9A is larger than the maximum opening of the second flow control valve 9B. (3) According to a third aspect of the present invention, in the crane turning control device according to the second aspect, as shown in FIG. 5, the second flow control valve 9B has an opening amount of the first flow control valve 9A. It has such a characteristic that the opening amount becomes 0 at a pilot pressure lower than the pilot pressure which starts increasing. (4) According to a fourth aspect of the present invention, in the crane turning control device according to the third aspect, as shown in FIGS.
Of the first flow control valve 9A has a faster response than the first flow control valve 9A. (5) According to a fifth aspect of the present invention, in the crane turning control device according to the first aspect, as shown in FIG.
Is a single flow control valve 9D provided between the two pipe lines 6A and 6B, and the control means 12 is connected to the single flow control valve 9D.
And a pilot pressure supply means 9C for supplying a pilot pressure according to a drive command from a single flow control valve 9D.
Is driven in accordance with the pilot pressure supplied from the pilot pressure supply means 9C. (6) According to a sixth aspect of the present invention, in the crane turning control device according to any one of the first to fifth aspects, FIGS.
As shown in FIG. 2, a pressure detecting means 1 for detecting pressures of two pipe lines 6A and 6B and outputting pressure signals P1 and P2, respectively.
0A, 10B, a rotational speed detecting means 11 for detecting a physical quantity based on the rotational speed of the turning hydraulic motor 2 and outputting a rotational speed signal S1, and a mode selecting means 13 for selecting a neutral brake mode and a neutral free mode. Provided, control means 12
However, when the neutral brake mode is selected, two lines 6
A and 6B are cut off, and when the neutral free mode is selected, a drive command A for communicating the two pipelines 6A and 6B is output based on the pressure signals P1 and P2 and the rotation speed signal S1. .

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 easy to understand. However, the present invention is not limited to this.

[0008]

Embodiments of the present invention will be described below with reference to the drawings. -First Embodiment- FIG. 1 is a circuit diagram showing a configuration of a turning control device according to a first embodiment of the present invention, and FIG. 2 is a side view of a crane having the turning control device. . As shown in FIG. 2, the mobile crane includes a traveling body 41, a revolving body 43 rotatably mounted on the traveling body 41 via a revolving device 42, and a boom supported by the revolving body 43 so as to be able to undulate. The hoisting rope 46 is wound around the hoisting drum 46 around which the hoisting rope 45 is wound, and the hoisting load 48 is moved up and down through the hook 47 connected to the hoisting rope 45 via the end of the boom 44. I do.

As shown in FIG. 1, a hydraulic circuit for turning the mobile crane includes a hydraulic pump 3 driven by a motor 101 and a hydraulic motor 2 for turning driven by pressure oil discharged from the hydraulic pump 3. A turning control valve 1 that controls the flow of pressure oil supplied from the hydraulic pump 3 to the turning hydraulic motor 2 and shuts off a pair of ports communicating with the inlet / outlet port of the hydraulic motor 2 when in neutral. An operating lever 5 for inputting a turning command, pilot valves 4A and 4B operated by the operating lever 5, and two pipelines 6A, 6A,
6B, a pilot hydraulic pressure source 7 for supplying pressure oil to the pilot valves 4A and 4B, and check valves 8A and 8B connected between the center port of the turning control valve 1 and the pipelines 6A and 6B.
A valve device 9 for communicating or shutting off the two pipes 6A, 6B via throttles, and pressure sensors 10A, 10B for measuring oil pressure in the pipes 6A, 6B and outputting pressure signals P1, P2.
The rotation speed sensor 11 which detects the rotation speed of the revolving body 43 proportional to the turning speed and outputs a plus signal S1 during normal rotation and a minus signal S1 during reverse rotation, and a neutral free / neutral brake system is selected. , A mode selection switch 13 for outputting a mode signal m, a controller 12 for controlling the drive of the valve device 9 in accordance with signals from the pressure sensors 10A and 10B, the rotation speed sensor 11 and the mode selection switch 13, and The revolving unit 43 has a brake device 14 for operating a negative brake according to a command.

The valve device 9 comprises a main hydraulic switching valve 9A and a sub hydraulic switching valve 9 arranged in parallel between the pipelines 6A and 6B.
B and an electromagnetic proportional pressure-reducing valve 9C for controlling the driving of the hydraulic switching valves 9A and 9B, respectively. The signals from the pressure sensors 10A, 10B, the rotation speed sensor 11, and the mode selection switch 13 are transmitted to the I / O port 1 of the controller 12.
2A and cpu12B
Performs a predetermined operation. The calculation result is output to the driver 12C, and the driver 12C drives the electromagnetic proportional pressure reducing valve 9C. Thus, the degree of pressure reduction of the electromagnetic proportional pressure reducing valve 9C is controlled, and the hydraulic switching valves 9A, 9B
The pilot pressure from the hydraulic pressure source 7 corresponding to the source pressure of the electromagnetic proportional pressure-reducing valve 9C is supplied to the pilot ports.

Next, referring to FIGS. 3 to 7, the hydraulic switching valve 9A,
The valve characteristics of 9B will be described. In this case, for the sake of simplicity, explanations will be made using specific numerical values.
The numerical value is merely an example, and the present invention is not limited to this. FIG. 3 is a view showing the relationship between the pilot pressure acting on the hydraulic switching valves 9A and 9B and the stroke amount of the spool. In the drawing, a solid line indicates the stroke characteristics of the hydraulic switching valve 9A, and a dotted line indicates the stroke characteristics of the hydraulic switching valve 9B. As shown in FIG. 3, the hydraulic switching valve 9B starts a stroke at a pilot pressure of 0.4 MPa, and reaches a full stroke at a pilot pressure of 0.8 MPa. On the other hand, the hydraulic switching valve 9A starts the stroke at the pilot pressure of 1 MPa after the hydraulic switching valve 9B reaches the full stroke, and reaches the full stroke at the pilot pressure of 3 MPa. The hydraulic switching valves 9B and 9A each have a pilot pressure of 0.5 MPa,
Stroke reaches 2 mm at 1.4 MPa.

The relationship between the stroke amount and the opening area of the hydraulic switching valves 9A and 9B having such stroke characteristics is as shown in FIG. 4A shows the characteristics of the hydraulic switching valve 9A, and FIG. 4B shows the characteristics of the hydraulic switching valve 9B. As shown in FIG. 4, the opening area of the hydraulic switching valve 9A is 0 when the stroke is in the range of 0 to 2 mm, and the opening area is increased with the increase in the stroke in the range of 2 to 10 mm, and the stroke is 10 mm or more. And the opening area becomes 100 mm2 at the maximum. The opening area of the hydraulic switching valve 9B is 10 mm2 at the maximum when the stroke is in the range of 0 to 2 mm, and the opening area decreases with the increase in the stroke in the range of 2 to 10 mm. It becomes 0. As described above, the change pattern of the opening area with respect to the stroke is reversed in the hydraulic switching valve 9A and the hydraulic switching valve 9B, and the maximum value of the opening area is remarkably larger in the hydraulic switching valve 9A than in the hydraulic switching valve 9B. It is getting bigger.

3 and 4, the hydraulic switching valves 9A and 9B
The relationship between the pilot pressure and the opening area is as shown in FIG. FIGS. 5A and 5B show the characteristics of the opening area of the hydraulic switching valves 9A and 9B, respectively, and FIG.
The characteristics of the opening area of the valve device 9 as a whole obtained by adding the characteristics of (a) and (b) are shown. As shown in FIG.
The opening area of the entire valve device 9 is such that the pilot pressure is 0.
It is equal to the opening area of the hydraulic switching valve 9B at 8 MPa or less, 0 when the pilot pressure is in the range of 0.8 to 1.4 MPa, and equal to the opening area of the hydraulic switching valve 9A at the pilot pressure of 1.4 MPa or more. .

Here, the neutral free / neutral brake modes will be described. The neutral free mode is a mode in which a driving torque is generated in the operation direction of the operation lever 5 and the hydraulic motor 2 is driven.
In this mode, even if the operation lever 5 is returned to the neutral position, no braking force other than the turning resistance acts on the hydraulic motor 2 and the revolving body 43 rotates by inertia force. Such a mode is suitable, for example, when the swing of the suspended load 48 is reduced. In the present embodiment, in the neutral free mode, the sensors 10A, 1
The pilot pressure supplied to the hydraulic switching valves 9A, 9B in response to signals from 0B, 11 is controlled within a range of 1.4 MPa or more, and the hydraulic switching valve 9A is opened. Thereby, the pipeline 6
The communication between A and 6B is allowed, and the hydraulic motor 2 is rotated by the inertial force.

On the other hand, the neutral brake mode is a mode in which the hydraulic motor 2 is driven in accordance with the operation amount of the operation lever 5, and in this mode, when the operation lever 5 is returned to the neutral position, the hydraulic motor 2 Acts, and the rotation of the rotating body 43 stops. Such a mode is suitable, for example, when performing fine positioning of the rotating body 43. In the present embodiment, the hydraulic switching valve 9 is in the neutral brake mode.
Pilot pressure supplied to A and 9B is 0.8 ~ 1.4MPa
And the opening areas of the hydraulic switching valves 9A and 9B are set to 0.
And As a result, communication between the pipelines 6A and 6B is prevented, and a braking force is applied to the hydraulic motor 2.

When the electromagnetic proportional pressure reducing valve 9C is driven from the non-energized state, the response delay causes the hydraulic switching valve 9C to operate.
A, 9B is not immediately supplied with the predetermined pilot pressure. Therefore, a predetermined current (offset signal A0) is previously output to the solenoid of the electromagnetic proportional pressure reducing valve 9C, and a predetermined pilot pressure (offset pressure) is supplied to the pilot ports of the hydraulic switching valves 9A and 9B in an initial state. The offset pressure in this case is set to a value (for example, 1 MPa) that prevents communication between the pipelines 6A and 6B. by this,
Even immediately after the drive command for the revolving unit 43, the hydraulic switching valve 9
A is stroked with good responsiveness. In addition, the supply of the offset pressure causes the valve device 9 to shut off the bypass passage between the pipelines 6A and 6B, for example, at the start of turning.

Next, the hydraulic switching valves 9A, 9B
The dynamic characteristics of the hydraulic switching valves 9A and 9B when the pilot pressure supplied to the hydraulic pressure change suddenly will be described. FIG.
FIG. 6 is a diagram showing dynamic stroke characteristics of the hydraulic switching valves 9A and 9B. As shown in FIG. 6A, the pilot pressure is rapidly increased from the offset pressure to 3 MPa in 2 seconds,
When it is reduced to 0 at a time in 7 seconds, the hydraulic switching valve 9
A and 9B make strokes as shown in FIGS. 6B and 6C, respectively. Here, the hydraulic switching valves 9A and 9B have a predetermined response delay (first-order delay) with respect to the input of the pilot pressure.
, And the response of the hydraulic switching valve 9A is later than that of the hydraulic switching valve 9B. The dynamic characteristics of such hydraulic switching valves 9a and 9B are determined by the spring force and the mass of the spool.

From the relationship between FIGS. 4 and 6, the characteristics of the opening areas of the hydraulic switching valves 9A and 9B when the input of the pilot pressure is suddenly stopped for 7 seconds are as shown in FIG. FIG.
(A) and (b) respectively show the dynamic characteristics of the opening area of the hydraulic switching valves 9A and 9B, and 7 (c) shows the entire valve device 9 that combines the characteristics of FIGS. 7 (a) and 7 (b). 3 shows the dynamic characteristics of the opening area. Since the response of the hydraulic switching valve 9A to the change in pilot pressure is slower than the response of the hydraulic switching valve 9B, as shown in FIG. 7 (c), the opening area of the entire valve device 9 gradually increases from 100 mm2 to 10 mm2. Decrease to 0 on the way
Never be. In this regard, if the response of the hydraulic switching valve 9A to the change of the pilot pressure is equal to the response of the hydraulic switching valve 9B, the pilot pressure becomes 0.8 to 1.4 MPa.
, The stroke of the hydraulic switching valve 9A becomes 2 mm or less, and the stroke of the hydraulic switching valve 9B becomes 10 mm.
Instantaneously becomes zero.

Next, the contents of the calculation in the controller 12 will be described. FIG. 8 is a diagram showing calculation contents in the controller 12 constituting the turning control device according to the first embodiment. As shown in FIG. 8, the controller 12 takes in the rotation speed signal S1 from the rotation speed sensor 11, and outputs the rotation speed signal S1 to a predetermined reduction ratio α (α = 1 in this embodiment).
And the displacement q per rotation of the hydraulic motor 2
And the flow rate QAB (= S
1 × α × q: This is hereinafter referred to as a target flow rate), and the flow rate calculator 21 takes in the pressure signals P1 and P2 from the pressure sensors 10A and 10B, subtracts P1 from the pressure signal P2, and subtracts the difference. A differentiator 22 for calculating the signal ΔP (= P2−P1), a sign discriminator 23 for judging the sign of the difference signal ΔP, and a predetermined target flow rate QAB as shown in FIG.
And a control signal A, the target flow rate QAB
Conversion tables 24A and 24B for converting
And the mode signal m from the mode changeover switch 13 is determined. When the neutral free mode is selected, the control signal A is output to the solenoid of the electromagnetic proportional pressure reducing valve 9C as it is, and when the neutral brake mode is selected. Has a mode discriminator 25 that outputs an offset signal A0. Area of the target flow rate QAB ≦ 0 in the conversion table 24A,
In a region where the target flow rate QAB ≧ 0 in the conversion table 24B, a limiter process is performed so that the control signal A = A0. Further, target flow rate QAB of conversion table 24A>
0 area and the target flow rate QAB of the conversion table 24B
In the region of <0, the control signal A has a value proportional to the target flow rate QAB.

The valve characteristics of the electromagnetic proportional pressure-reducing valve 9C are set so that the degree of pressure reduction becomes smaller as the control signal from the controller 12 increases. When the control signal A = A0, the electromagnetic proportional pressure-reducing valve 9C is set to the initial state. The pilot pressure of the hydraulic switching valves 9A and 9B is applied to the aforementioned offset pressure (for example, 1MP).
a) is supplied.

Next, the operation of the first embodiment will be described. In the following description, the direction in which the hydraulic motor 2 rotates by the pressure oil from the line 6A is referred to as the normal rotation direction, and the line
The direction in which the hydraulic motor 2 is rotated by the pressure oil from is defined as the reverse rotation direction.

(1) Neutral brake mode When the neutral brake mode is selected by the mode changeover switch 13, as described above, the mode discriminator 25 sends the offset signal A0 to the solenoid of the electromagnetic proportional pressure reducing valve 9C.
Is output. Thereby, the offset pressure 1 MPa is supplied to each of the hydraulic switching valves 9A and 9B, and the hydraulic switching valve 9
A and 9B are closed according to the characteristics of FIG.
Communication between A and 6B is blocked. When the operation lever 5 is actuated from the neutral position to the forward rotation side, the pilot valve 4A is driven according to the operation amount, and the pilot hydraulic power source 7
Is supplied to the pilot port of the direction control valve 1 via the pilot valve 4A. As a result, the direction control valve 1 is switched to the position (a), and the pressure oil from the hydraulic pump 3 is supplied to the hydraulic motor 3 via the direction control valve 1 and the pipeline 6A. As a result, the hydraulic motor 2 is rotated in the normal rotation direction, and the revolving unit 43 is driven at a speed corresponding to the operation amount of the operation lever 5.

When the operating lever 5 is returned to the neutral side during the forward rotation of the revolving unit 43, the pilot pressure is reduced in accordance with the operation amount, and the direction control valve 1 is driven to the neutral side. As a result, the throttle (meter-out throttle) by the direction control valve 1 is closed, the pressure in the pipeline 6B increases, a brake pressure is generated, and the rotation of the swing body 43 is reduced. When the operation lever 5 is completely returned to the neutral position, the pipelines 6A and 6B are blocked from the hydraulic pump 3 and the tank, and the rotation of the rotating body 43 is stopped immediately. In this state, the revolving unit 4
3 does not rotate even if some external force acts on it. The above operation is the same when the revolving unit 43 is driven in the reverse direction.

(2) Neutral Free Mode When the neutral free mode is selected by the mode changeover switch 13 and the operation lever 5 is actuated from the neutral position to the normal rotation side, the directional control valve 1 is moved to the position (a) as described above. ), And the hydraulic motor 2 is rotated in the normal rotation direction. At this time, the signal S output from the rotation speed sensor 11
Since 1 is plus (> 0), the target flow rate QAB> 0, and the signals P1, P2 output from the pressure sensors 10A, 10B are P1> P2, so the differential pressure signal ΔP <0.
Becomes As a result, the code discriminator 23 converts the conversion table 24
B is selected and subjected to a limiter process on the offset signal A0 in the conversion table 24B, and the offset signal A0 is output as it is to the electromagnetic proportional pressure reducing valve 9C. On the other hand, if the operation lever 5 is operated in the reverse rotation direction at the time of startup, the signal S1 output from the rotation speed sensor 11 is minus (<0), so that the target flow rate QAB <0, and the pressure sensors 10A, 1
Since the signals P1 and P2 output from 0B satisfy P1 <P2, the differential pressure signal ΔP> 0. As a result, the code discriminator 2
3 selects the conversion table 24A, and selects the conversion table 24A.
Is subjected to a limiter process on the offset signal A0, and the offset signal A0 is output to the electromagnetic proportional pressure reducing valve 9C.

As described above, at the time of start-up, the offset signal A0 is output to the electromagnetic proportional pressure reducing valve 9C, and the communication between the pipelines 6A and 6B is blocked as in the above-described neutral brake mode, and the revolving unit 43 is operated by the operating lever. 5 is driven at a speed corresponding to the operation amount. The offset signal A0 is similarly output to the electromagnetic proportional pressure reducing valve 9C when the operation lever 5 is held at a predetermined position on the forward rotation side or the reverse rotation side and when the operation lever 5 is accelerated.

When the operating lever 5 is operated to the neutral position during the forward rotation of the revolving unit 43, the pilot pressure to the directional control valve 1 is reduced, and the directional control valve 1 is driven to the neutral position.
The pressure in B increases. At this time, since the signal S1 output from the rotation speed sensor 11 is positive, the target flow rate QA
B> 0, but the signals P1 and P2 output from the pressure sensors 10A and 10B are P1 <P2, so that the difference signal Δ
Since P> 0, the code discriminator 23 uses the conversion table 24A.
And the control signal A (> A0) in the conversion table 24A.
Is calculated. The electromagnetic proportional pressure reducing valve 9C is driven in accordance with the control signal A, and the pilot pressure acting on the pilot port increases. As a result, the hydraulic switching valve 9A becomes
The opening area increases according to the characteristics of the target flow rate QAB
Flows from the pipe 6B to the pipe 6A via the hydraulic switching valve 9A. As a result, the hydraulic pressure in the pipeline 6B decreases, and the revolving structure 43 rotates with inertia without applying a hydraulic braking force to the hydraulic motor 2. In addition, since the turning resistance actually acts on the rotating body 43 rotating in this way, the driving of the rotating body 43 is stopped soon. Revolving superstructure 43
In order to forcibly stop the drive, the operation lever 5 may be operated in the opposite direction (so-called reverse lever) to increase the oil pressure in the pipe 6B. In addition, when the revolving structure 43 is stopped at a predetermined position on a slope or the like, the brake device 14 is operated.

(3) When disconnection occurs Revolving unit 4 in neutral brake mode or neutral free mode
When the control signal A is output to the electromagnetic proportional pressure reducing valve 9C due to disconnection or the like during the driving of the motor 3 and the drive command A is not output (A = 0), the electromagnetic proportional pressure reducing valve 9C is closed and the hydraulic pressure is switched. The pilot pressure acting on the valves 9A and 9B becomes zero at a stretch. At this time, the positions of the hydraulic switching valves 9A and 9B are not immediately switched, and the hydraulic switching valves 9A and 9B stroke according to the characteristics shown in FIGS. As a result, the opening area of the entire valve device 9 decreases as shown in FIG. 7C and converges to a constant value of 10 mm2. As a result, even if the disconnection occurs during the driving of the rotating body 43, the communication between the pipelines 6A and 6B is not interrupted, the rotation of the hydraulic motor 2 is gradually reduced, and the shock of the rotating body 43 is reduced. Is prevented.

When the operating lever 5 is actuated in this state, a portion of the hydraulic oil from the hydraulic pump 1 is partially released from the hydraulic motor 2 because the pipes 6A and 6B communicate with an opening area of 10 mm2.
Bypass. However, since the opening area of the valve device 9 is as small as about 10% of the maximum opening area, a sufficient driving torque can be generated in the hydraulic motor 2 and the revolving structure 43 can be started. When the operating lever 5 is returned to the neutral position, the deceleration becomes the same as that in the neutral free mode when the opening area of the valve device 9 is 10 mm2,
3, since the deceleration shock is reduced and the opening area is small, the hydraulic braking force in the neutral brake mode is also applied to a small extent, and the driving of the revolving unit 43 can be stopped immediately.

As described above, according to the first embodiment, the hydraulic switching valves 9A and 9B are provided between the conduits 6A and 6B connecting the entrance and exit ports of the hydraulic motor 2, and the hydraulic switching valve 9A is provided by the electromagnetic proportional pressure reducing valve 9C. , 9B by controlling the driving of the pipelines 6A, 6B.
B and the electromagnetic proportional pressure reducing valve 9
A small amount of communication was established between the pipes 6A and 6B when C was not energized. Thus, the neutral free mode and the neutral brake mode can be realized by one circuit, and even if the electromagnetic proportional pressure reducing valve 9C is de-energized due to disconnection or the like when the revolving unit 43 is driven, the hydraulic motor 2 stops suddenly. However, the shock of the rotating body 43 is reduced. Further, in this case, the response time of the hydraulic switching valves 9A and 9B is delayed, and the response of the hydraulic switching valve 9A is made slower than the response of the hydraulic switching valve 9B, so that the opening area between the pipelines 6A and 6B gradually increases. , And does not become 0 instantaneously, and the shock of the revolving unit 43 is further reduced. Further, since the opening area of the valve device 9C is made very small at the time of disconnection, the starting and stopping of the revolving unit 43 can be performed relatively smoothly thereafter.

-Second Embodiment- A second embodiment of the present invention will be described with reference to FIG.
FIG. 9 is a hydraulic circuit diagram showing a configuration of a turning control device according to the second embodiment of the present invention. The same portions as those in FIG. 1 are denoted by the same reference numerals, and the differences will be mainly described below. As shown in FIG. 9, in the second embodiment,
A hydraulic switching valve 9D is provided instead of the hydraulic switching valves 9A and 9B. The hydraulic switching valve 9D is switched by the pilot pressure from the electromagnetic proportional pressure reducing valve 9C.
This is the same as that shown in FIG. That is, when the pilot pressure is 0.5 MPa or less, the hydraulic switching valve 9D is switched to the position (a), and a predetermined opening area of 10 m is provided between the pipelines 6A and 6B.
Connect with m2. Thereafter, as the pilot pressure increases, the opening area decreases, and when the pilot pressure is in the range of 0.8 to 1.4 MPa, the hydraulic switching valve 9D is switched to the position (b), and the communication between the pipelines 6A and 6B is cut off. . Furthermore, the opening area increases as the pilot pressure increases, and the pilot pressure becomes 3MP.
Above a, the hydraulic switching valve 9D is switched to the position (c), and the pipes 6A and 6B communicate with an opening area of 100 mm2. The dynamic characteristics of the hydraulic switching valve 9D are, for example, those shown in FIG.
This is the same as that shown in FIG.

The controller 12 performs the same calculation as described above. In the neutral brake mode, an offset signal A0 is output to the electromagnetic proportional pressure reducing valve 9C, and the electromagnetic proportional pressure reducing valve 9C outputs a predetermined pilot pressure of 1 MPa. The hydraulic switching valve 9D is switched to the position (b). Also, during the deceleration operation in the neutral free mode, the electromagnetic proportional pressure reducing valve 9 is used.
Pressure sensors 10A and 10B and rotation speed sensor 11
A control signal A (> A0) corresponding to the signal from
The hydraulic switching valve 9D is switched to the position (c). When the output of the control signal to the electromagnetic proportional pressure reducing valve 9C is stopped (A = 0) due to disconnection or the like during driving of the revolving unit 43, the hydraulic switching valve 9
D is switched to the position (a) according to the characteristic of FIG. At this time, the opening area temporarily becomes zero,
Immediately increasing to the predetermined value of 10 mm2, the shock is not so problematic.

As described above, in the second embodiment, the communication between the pipelines 6A and 6B is established or cut off by switching the single hydraulic switching valve 9D, thereby enabling the neutral brake mode and the neutral free mode to be realized. When the electromagnetic proportional pressure reducing valve 9C is not energized, a predetermined amount of communication is established between the pipelines 6A and 6B. Thereby, the shock when disconnection or the like occurs at the time of driving the revolving structure 43 is reduced, the number of parts is reduced, and the cost and space efficiency are improved.

In the above embodiment, the hydraulic switching valve 9
A, 9B and 9D are switched to communicate or cut off between the pipelines 6A and 6B, but the hydraulic switching valves 9A, 9B and 9D are switched.
Using an electromagnetic proportional flow control valve instead of
The electromagnetic proportional flow control valve may be directly controlled by the control signal from the control unit 2. Thereby, the electromagnetic switching pressure reducing valve 9
C can be omitted. Further, in the above-described embodiment, the valve device 9 is configured as a circuit capable of realizing both the neutral free mode and the neutral brake mode. However, the selection switch 13 may be omitted and a dedicated circuit for the neutral brake mode may be configured. . In that case, for example, in order to suppress pressure fluctuation and speed fluctuation of the revolving unit 43, the sensors 10A, 1
What is necessary is just to control the drive of the valve device 9 according to the input signal from 0B, 11. Further, the turning control device in the above embodiment is applied to a crane, but can also be applied to a hydraulic shovel.

In the correspondence between the above embodiment and the claims, the directional control valve 1 controls the control valve, the controller 12 controls the control means, the hydraulic switching valve 9A controls the first flow control valve, and the hydraulic switching valve 9B controls the hydraulic switching valve 9B. The second flow control valve, 9C is pilot pressure supply means, the hydraulic switching valve 9D is a single flow control valve, the pressure sensors 10A and 10B are pressure detection means, and the rotation speed sensor 11 is rotation speed detection means. , The mode selection switch 13 constitutes a mode selection means.

[0035]

As described above in detail, according to the present invention, the two pipes respectively connected to the entrance and exit ports of the turning hydraulic motor are communicated and blocked in accordance with the drive command from the control means. When the drive command is not output from the control means, the two pipes are connected to each other with a predetermined opening area so that the two pipes are shut off and the hydraulic motor is not suddenly stopped. Thus, even when the signal output from the control unit is stopped due to a disconnection or the like, the revolving superstructure is not suddenly stopped, and the shock of the revolving superstructure can be reduced. In particular, according to the invention of claim 4, the responsiveness of the first flow control valve and the second flow control valve for communicating and blocking the two pipes are different from each other, so that the opening area is zero. Instead, it can be reduced to a predetermined opening area.
Further, according to the fifth aspect of the present invention, since the two pipes are connected and disconnected by the single flow control valve, the number of parts is reduced, and cost and space efficiency are improved. Further, according to the invention of claim 6, the neutral free mode and the neutral brake mode can be selected with one circuit, and workability is improved.

[Brief description of the drawings]

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

FIG. 2 is a side view of the crane to which the present invention is applied.

FIG. 3 is a diagram illustrating a relationship between a pilot pressure and a spool stroke of a hydraulic switching valve included in the turning control device according to the first embodiment.

FIG. 4 is a diagram showing a relationship between a stroke and an opening area of a hydraulic switching valve included in the turning control device according to the first embodiment.

FIG. 5 is a diagram showing a relationship between pilot pressure and an opening area of a hydraulic switching valve included in the turning control device according to the first embodiment.

FIG. 6 is a view showing characteristics of a dynamic stroke of a hydraulic switching valve included in the turning control device according to the first embodiment.

FIG. 7 is a diagram showing characteristics of a dynamic opening area of a hydraulic switching valve included in the turning control device according to the first embodiment.

FIG. 8 is a diagram showing a part of the calculation contents in a controller constituting the turning control device according to the first embodiment.

FIG. 9 is a hydraulic circuit diagram of a turning control device according to a second embodiment of the present invention.

[Description of Signs] 1 Direction control valve 2 Hydraulic motor for turning 3 Hydraulic pump 6A, 6B Pipe line 9 Valve device 9A, 9B Hydraulic switching valve 9C Electromagnetic proportional pressure reducing valve 9D Hydraulic switching valve 10A, 10B Pressure sensor 11 Revolution sensor 12 Controller 13 Mode selection switch

 ──────────────────────────────────────────────────の Continuing on the front page (72) Inventor Junichi Narusawa 650, Kandamachi, Tsuchiura-shi, Ibaraki Prefecture Inside the Tsuchiura Plant of Hitachi Construction Machinery Co., Ltd. Inside the Tsuchiura Plant, Ltd. (72) Kazuhisa Ishida, 650, Kandamachi, Tsuchiura-shi, Ibaraki Prefecture Inside the Tsuchiura Plant, Hitachi Construction Machinery Co., Ltd. 3F205 AA07 BA06 CA01 DA03 EA09 3H089 AA60 AA68 BB06 CC08 DA02 DB12 DB47 DB49 EE03 EE22 EE36 FF07 FF10 GG02 JJ08

Claims (6)

[Claims] 1. A hydraulic pump, a turning hydraulic motor driven by hydraulic oil discharged from the hydraulic pump, and a flow of hydraulic oil supplied from the hydraulic pump to the hydraulic motor, wherein the hydraulic oil is A control valve for shutting off a pair of ports communicated with an inlet / outlet port of the motor, a valve device for communicating and shutting off two pipelines respectively connected to the inlet / outlet port of the hydraulic motor, and outputting a drive command to the valve device A control device for controlling the crane's turning, wherein the valve device is driven so as to communicate and cut off the two pipelines in response to the drive command from the control device, and When the drive command is not output from the means, the two pipes are communicated with a predetermined opening area so that the two pipes are shut off and the hydraulic motor does not stop suddenly. Turning control apparatus for a crane according to claim Rukoto. 2. The turning control device for a crane according to claim 1, wherein the valve device includes a first flow control valve and a second flow control valve provided in parallel between the two pipelines. , These first
And a pilot pressure supply unit for supplying a pilot pressure according to the drive command from the control unit to the flow control valve and the second flow control valve, wherein the first flow control valve and the second flow control The valve increases the opening amount of the first flow control valve and decreases the opening amount of the second flow control valve, respectively, as the pilot pressure supplied from the pilot pressure supply unit increases, and A turning control device for a crane, characterized in that a maximum opening of the first flow control valve is larger than a maximum opening of the second flow control valve. 3. The swivel control device for a crane according to claim 2, wherein the second flow control valve has a pilot pressure lower than a pilot pressure at which the opening of the first flow control valve starts increasing. A crane turning control device characterized in that the opening amount is zero. 4. The crane turning control device according to claim 3, wherein the second flow control valve has a quicker response than the first flow control valve. apparatus. 5. The swivel control device for a crane according to claim 1, wherein the valve device includes a single flow control valve provided between the two pipes, and the single flow control valve. Pilot pressure supply means for supplying a pilot pressure according to the drive command from the control means, wherein the single flow control valve is driven in accordance with the pilot pressure supplied from the pilot pressure supply means. A turning control device for a crane. 6. The turning control device for a crane according to claim 1, wherein a pressure detecting unit that detects a pressure of each of the two pipes and outputs a pressure signal, and the turning hydraulic pressure. A rotation speed detection unit that detects a physical quantity based on the rotation speed of the motor and outputs a rotation speed signal; anda mode selection unit that selects a neutral brake mode and a neutral free mode. When selected, the two pipes are cut off, and when the neutral free mode is selected, the drive command is output to connect the two pipes based on the pressure signal and the rotation speed signal. A turning control device for a crane.