JPH06330535A - Variation suppressing apparatus for hydraulic machine - Google Patents

Abstract

PURPOSE:To suppress vibrations of a hydraulic machine with immediate response, by controlling the flow rate of an auxiliary hydraulic oil in response to the pressure of a hydraulic actuator. CONSTITUTION:An accumulator 7 is jointed with a pipe line 11 connecting the head side of a boom cylinder and a flow control valve 4. And a variable restrictor 8a is arranged in the pipe line connecting the pipe line 11 and the accumulator 7. The pressure before and after the variable restrictor 8a is detected by pressure sensors 10a, 10b and the differencial pressure of the variable ristrictor 8a is obtained from the detected pressures by use of a control unit 9 and the absolute value of multiplied figure of the differencial pressure by the control gain is output the solenoid controller 8c of the variable restrictor 8a as an instructing value of flow rate. In this way, the opening of variable restrictor 8a is controlled in accordance with the variation of pressure and vibration is suppressed with good response.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vibration suppressing device for a hydraulic working machine, and more particularly to a hydraulic working machine such as a hydraulic excavator, a crane, etc., which is suitable for suppressing vibration of a working device such as a boom or an arm. The present invention relates to a vibration suppressing device for a work machine.

[0002]

2. Description of the Related Art As a vibration suppressing device for a hydraulic working machine, an accumulator for energy storage is used as described in Japanese Patent Laid-Open No. 64-75722 to suppress the vibration of the working device when the hydraulic working machine is running. Vibration suppressing devices are known. FIG. 7 shows a hydraulic drive circuit in which this vibration suppression device is applied to a boom drive device of a hydraulic excavator.

In FIG. 11, this hydraulic drive circuit serves as a boom drive device, and includes a hydraulic pump 1, a boom cylinder 2 for driving a boom 2A, and a hydraulic fluid supplied to the boom cylinder 2 in response to an operation signal from an operating lever 3. A flow rate control valve 4 for controlling the flow rate and the oil feed direction, and a relief valve 5 for releasing the pressure oil to the tank 6 when the hydraulic pressure between the hydraulic pump 1 and the flow rate control valve 4 exceeds a predetermined value. Further, as a vibration suppressing device, an accumulator 7 for pressure storage connected to a pipe line between the flow control valve 5 and the boom cylinder, and a fixed throttle 80 arranged in a pipe line connecting the pipe line to the accumulator 7. Is equipped with.

In the above hydraulic drive circuit, when the vibration of the boom causes a pressure fluctuation in the pipe line between the boom cylinder 2 and the flow control valve 4 in response to the vibration, the pipe line moves from the pipe line when the pressure in the pipe line is high. The pressure oil flows out to the accumulator 7 via the fixed throttle 80, and when the pressure in the pipeline is low, the pressure oil flows into the pipeline from the accumulator 7 via the fixed throttle 80, which causes a pressure fluctuation, which is a vibrating force. The vibration of the boom is suppressed.

In Japanese Utility Model Laid-Open No. 64-14259, a variable throttle is arranged instead of the fixed throttle, and the pressure of the hydraulic actuator is taken out through the fixed throttle, and the opening of the variable throttle is changed to the fixed throttle. It is proposed to adjust the pressure depending on the pressure taken out. According to this configuration, the fixed throttle removes the fluctuation component of the pressure from the pressure of the hydraulic actuator, so that the opening of the variable throttle changes according to the steady component of the pressure of the actuator, which reduces the weight of the working device. Even if it increases, the peak value of the pressure change during vibration suppression does not increase, and the vibration suppression effect suitable for the load condition can be obtained.

[0006]

However, as shown in FIG.
In the conventional vibration suppressor disclosed in Japanese Patent Application Laid-Open No. 64-75722 shown in FIG. 1, since the pressure oil flows in and out through the fixed throttle 8, a sufficient vibration suppressing effect is obtained even when the pressure fluctuation is large. In order to obtain it, it is necessary to set the opening of the fixed throttle 80 to a large value. In this case, it takes a long time for the vibration to subside and the responsiveness decreases.

Further, in the prior art disclosed in Japanese Utility Model Laid-Open No. 64-14259, the opening of the variable throttle is changed according to the steady component of the pressure of the actuator, but the fluctuation component (the fluctuation component of the pressure of the actuator). Since the opening of the variable throttle does not change even when the pressure changes, it is necessary to set the opening of the variable throttle large when trying to obtain a sufficient damping effect even when the pressure fluctuation is large. Sex decreases.

Therefore, the conventional vibration suppressing device is not applied during the normal operation, but is applied only during the traveling when the responsiveness is not a serious problem.

An object of the present invention is to suppress vibration of a working device with good responsiveness by controlling auxiliary flow rate of pressure oil in accordance with pressure fluctuation of a hydraulic actuator, thereby suppressing vibration of a working machine. To provide.

[0010]

In order to achieve this object, the present invention provides a hydraulic pump, a hydraulic actuator driven by pressure oil discharged from the hydraulic pump,
Connected between the hydraulic pump and the hydraulic actuator,
A vibration suppressing device for a hydraulic working machine, comprising: a flow rate control valve that controls a flow rate of pressure oil supplied to the hydraulic actuator in accordance with an operation signal from an operating means; (a) a hydraulic pressure connected to the hydraulic actuator. A vibration suppressing circuit including a pressure accumulating means for energy storage and a variable throttle arranged in a pipe line connecting the hydraulic actuator and the pressure accumulating means; and (b) a variable throttle depending on a differential pressure across the variable throttle. And a throttle control means for controlling the opening.

The vibration suppressing device preferably further includes setting means for setting the opening / closing of the vibration suppressing circuit, and opening / closing means for opening / closing the vibration suppressing circuit by operating the setting means. In this case, the opening / closing means may be an opening / closing valve arranged in a pipeline connecting the hydraulic actuator and the pressure accumulating means.

Further, in the above vibration suppressing device, preferably, the throttle control means is based on a differential pressure detection means for detecting a differential pressure across the variable throttle and a differential pressure signal output from the differential pressure detection means. And a calculation means for calculating and outputting a flow rate command value, and the opening of the variable throttle is controlled based on the flow rate command value.

In this case, preferably, the differential pressure detecting means includes a first pressure detecting means for detecting a pressure in a conduit portion between the hydraulic actuator and the variable throttle, the variable throttle and the pressure accumulating means. Second pressure detecting means for detecting the pressure of the pipe portion between the two.

Further preferably, the calculating means obtains the absolute value of a value obtained by multiplying the differential pressure across the variable throttle by a control gain as the flow rate command value.

More preferably, the vibration suppressing device outputs by the setting means for setting the opening and closing of the vibration suppressing circuit, and the calculating means when the setting means closes the vibration suppressing circuit. An opening / closing means for keeping the flow rate command value at 0 is further provided.

Further, in the above vibration suppressing device, preferably, the throttle control means has actuator means for driving a valve body of the variable throttle by a differential pressure across the variable throttle to adjust an opening degree of the variable throttle. . In this case, preferably, the variable throttle has a notch formed in a central portion of the spool, and the actuator means includes a first hydraulic chamber that applies a pressure on the actuator side of the variable throttle to one end of the spool. And a second hydraulic chamber for applying a pressure on the accumulator side of the variable throttle to the other end of the spool.

[0017]

In the present invention constructed as described above, the vibration suppressing circuit basically has the same vibration suppressing effect as the conventional vibration suppressing device because the vibration suppressing circuit has the pressure accumulating means and the variable throttle. That is, when a pressure fluctuation corresponding to the vibration occurs in the hydraulic actuator due to the vibration of the work device, pressure oil flows from the hydraulic actuator to the pressure accumulating means via the variable throttle when the pressure is high, and when the pressure is low, the pressure accumulating means Pressure oil flows into the hydraulic actuator through the variable throttle,
This reduces pressure fluctuations and suppresses boom vibration.

However, this alone sacrifices the responsiveness as described above. In the present invention, vibration is suppressed with good responsiveness by controlling the opening of the variable throttle according to the differential pressure across the variable throttle by the throttle control means. That is, when the working device vibrates, when the fluctuation component of the pressure of the hydraulic actuator increases, the differential pressure across the variable throttle increases and the opening of the variable throttle increases, and when the fluctuation component of the pressure decreases, the differential pressure across the variable throttle decreases. Becomes larger and the opening of the variable throttle becomes smaller, so that the flow rate of the pressure oil flowing in and out through the variable throttle is controlled according to the pressure fluctuation, and the control flow rate per unit time becomes large. Therefore, the pressure fluctuation is rapidly reduced, and the vibration is suppressed with good responsiveness.

[0019]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A first embodiment of the present invention will be described below with reference to FIGS. 1 to 6 by taking a hydraulic excavator as an example of a hydraulic working machine. In FIG. 1, a hydraulic drive circuit according to the present embodiment is driven by a hydraulic pump 1 and pressure oil discharged from the hydraulic pump 1, and a hydraulic actuator or a boom cylinder that drives a boom 2A of a working device, for example, a hydraulic excavator. 2 and a flow rate control valve 4 that is connected between the hydraulic pump 1 and the hydraulic actuator 2 and that is controlled by a pilot pressure signal by the operation of the operation lever 3 and that controls the flow rate of the pressure oil supplied to the hydraulic actuator 2. It is provided with a relief valve 5 that opens when the pressure between the pump 1 and the flow control valve 4 becomes a set value or more.

The vibration suppressing device according to the present embodiment is provided in the hydraulic drive circuit described above, and includes an accumulator 7 for accumulating hydraulic energy and the boom cylinder 2 to the accumulator 7.
A variable throttle device 8 for controlling the flow rate of pressure oil flowing out to the boom cylinder 2 and a flow rate of pressure oil flowing into the boom cylinder 2 from the accumulator 7, and a control unit 9 controlling the variable throttle device 8.
Pressure sensors 10a and 10b for detecting the pressure in the pipeline 12.
And have.

The accumulator 7 is connected to a pipe line 11 connecting the head side of the boom cylinder 2 and the flow control valve 4, and the variable throttle device 8 is arranged in a pipe line 12 connecting the pipe line 11 and the accumulator 7. It has a variable throttle 8a, a pressure sensor 10a is connected to a pipe 12 on the boom cylinder side of the variable throttle 8a to detect the pressure on the head side of the boom cylinder 2, and a pressure sensor 10b is a pipe on the accumulator side of the variable throttle 8a. It is connected to 12 and detects the pressure on the accumulator side. The variable throttle device 8 also includes a spring 8b that biases the valve body of the variable throttle 8a in the valve closing direction, and a solenoid operating portion 8c that faces the spring 8b and drives the valve body of the variable throttle 8a to adjust the opening degree. Have The control unit 9 inputs a signal from the pressure sensor 10 to calculate a flow rate command value for vibration suppression, and outputs a corresponding flow rate command signal to the solenoid operating unit 8c of the variable throttle device 8. Variable diaphragm device 8
Controls the opening of the variable throttle 8a by the flow rate command signal, and controls the flow rate of the pressure oil flowing into and out of the accumulator 7.

In the above, the accumulator 7, the variable throttle 8a and the conduit 12 constitute the vibration suppressing circuit 100, and the spring 8b, the solenoid operating portion 8c, the control unit 9 and the pressure sensors 10a and 10b are the differential pressure across the variable throttle 8a. A diaphragm control means for controlling the opening of the variable diaphragm 8a according to the above.

The control unit 9 is composed of a microcomputer, and as shown in FIG.
A / which converts the signal output from 0b into a digital signal
A D converter 9a, a central processing unit (CPU) 9b,
A read-only memory (ROM) 9c for storing a control procedure program, a randem access memory (RAM) 9d for temporarily storing a numerical value during calculation, and an I for output.
An / O interface 9e and an amplifier 9f that outputs a flow rate command signal to the solenoid operating unit 8c of the variable throttle device 8 are provided.

The control unit 9 includes a pressure sensor 10a,
The differential pressure across the variable throttle 8a is obtained based on the signal output from 10b, and the absolute value of the value obtained by multiplying the differential pressure across the variable throttle 8a by the control gain is obtained as the flow rate command value.

The operation of this embodiment will be described in detail below with reference to the flow chart of the control procedure program shown in FIG. First, in step 100, the pressure sensor 10
The signals from a and 10b are input via the A / D converter 9a and stored in the RAM 9d as the head side pressure Pa of the boom cylinder 2 and the accumulator 7 side pressure Pb.

Next, in step 110, the head side pressure Pa of the boom cylinder 2 and the accumulator 7 side pressure Pb.
The differential pressure ΔP across the variable throttle 8 is calculated based on the difference between

The reason why the differential pressure ΔP across the variable aperture 8a is obtained will be described with reference to FIG. Boom cylinder 2A
When the input u (stroke) of the operation lever 3 is changed as shown in FIG. 4 (a) while the holding pressure of the boom cylinder is 100 Kg / cm ² , the speed V of the boom cylinder 2A becomes as shown in FIG.
It changes like (b), and the pressure P changes like FIG.4 (d). That is, at the time of starting and stopping the boom cylinder 2A, the pressure P becomes as shown in FIG. 4 (d) due to the inertia of the weight of the boom 2A and the weight supported by the boom 2A and the spring action of the pressure oil in the hydraulic circuit after the flow control valve 4. Changes as shown,
Along with this, the speed V also changes as shown in FIG. When the holding pressure, which is its steady component, is removed from the pressure P, only the fluctuation component Ph associated with start and stop is obtained as shown in FIG. 4 (e). The vibration component Vh when the velocity V is passed through the high pass filter is as shown in FIG. The vibration of the pressure P and the vibration of the velocity V have a 90 ° phase shift.

When the fluctuation component of the pressure P increases, the differential pressure across the variable throttle 8a also increases, and when the fluctuation component of the pressure P decreases, the differential pressure ΔP across the variable throttle 8a also decreases. Therefore, the differential pressure ΔP across the variable throttle 8a substantially matches the fluctuation component Ph in FIG.
h has a one-to-one correspondence with the acceleration of the boom cylinder 2. That is, in this embodiment, instead of directly detecting the acceleration that is the source of the exciting force, the acceleration is detected by obtaining the differential pressure ΔP across the variable aperture 8a.

Next, in step 120, the absolute value of the value obtained by multiplying the differential pressure ΔP by an appropriate gain Kp is calculated as the flow rate command value Δq, and the corresponding flow rate command signal is output to the solenoid operating portion 8c of the variable throttle device 8. Then go back to the beginning.

Next, the function and effect of this embodiment will be described with reference to FIGS. FIG. 5 shows an input u (pilot pressure) of the operation lever 3 when the boom is suddenly stopped in the hydraulic excavator including the conventional vibration suppressing device shown in FIG.
The time change of the displacement X of the boom cylinder 2, the pressure P of the boom cylinder 2, the opening A of the fixed throttle 80, and the control flow rate Q passing through the fixed throttle 80 is shown in comparison with the case without the vibration suppressing device. In the figure, the solid line shows the case where the vibration suppressing device is provided, and the broken line shows the case where the vibration suppressing device is not provided.

When the operating lever 3 is returned to the neutral position in order to suddenly stop the boom 2A from the state in which the boom is lowered at a constant speed, the input u becomes 0 as shown in FIG. Valve 4 also returns to neutral. Along with this, the speed V (the inclination of the cylinder displacement X) and the pressure P which have been constant until then
The boom cylinder 2 that was operating in the lowering direction tries to stop, but due to inertia, the boom 2A does not stop suddenly, and continues to lower beyond the target position as shown in FIG. Correspondingly, the pressure P of the boom cylinder 2 also changes as shown in FIG.

That is, when there is no vibration suppressing device, as shown by the dotted line, the pressure P increases immediately after the displacement X of the boom cylinder 2 exceeds the target position, and the cylinder speed V becomes 0 accordingly. . After that, in the hydraulic circuit after the flow control valve 4, the pressure oil acts as a spring to push the boom cylinder 2 back upward, the cylinder displacement X starts to increase, and the speed V turns to a positive value and the pressure P. Begins to decline. When the boom cylinder 2 is pushed back to the predetermined position, similarly, the boom cylinder 2 is pushed back to the lower side by the spring action of the pressure oil, the cylinder displacement X starts to decrease, and the speed V turns to a negative value. And the pressure P starts to increase. The above process is repeated, and vibration is generated in the front system including the boom 2A. This vibration is applied to the vehicle body, causing the vehicle body to rock due to the influence of rattling of the vehicle body and the like, resulting in coupled vibration of the entire vehicle body-front.

When the conventional vibration suppressing device is provided, as shown by the solid line, when the pressure P increases after the displacement X of the boom cylinder 2 exceeds the target position, as shown in FIG. 5 (e). When pressure oil flows out from the hydraulic circuit after the flow control valve 4 to the accumulator 7 via the fixed throttle 80, and the boom cylinder 2 is pushed back upward, as shown in FIG. 5 (e), it is fixed from the accumulator 7. Pressure oil flows into the hydraulic circuit after the flow control valve 4 through the throttle 80. For this reason,
Due to the accumulator action of the accumulator 7 and the damping action of the fixed throttle 80, the pressure fluctuation gradually decreases as shown in FIG. 5C, and the vibration generated in the front system including the boom 2A gradually decreases.

Since the fixed diaphragm 80 is used in the conventional vibration suppressing device, the diaphragm opening A is shown in FIG.
As shown in (d), it is constant, and its opening is set large in order to obtain a sufficient damping effect. For this reason, the cycle of vibration becomes long, the time until the vibration subsides becomes long, and the responsiveness deteriorates.

FIG. 6 is a view similar to FIG. 5 of the hydraulic excavator equipped with the vibration suppressing device of this embodiment shown in FIG. However, FIG. 6D shows the opening A of the variable aperture 8a. Also in this figure, comparison is made with the case without the vibration suppressing device. In the figure, the solid line shows the case where the vibration suppressing device of the present embodiment is provided, and the broken line shows the case where the vibration suppressing device is not provided.

In the vibration suppressing device of this embodiment, the variable diaphragm 8
The differential pressure ΔP before and after a, that is, the fluctuation component of the pressure P is calculated to calculate the flow rate command value Δq, and the opening A of the variable throttle 8a is controlled. The opening A changes as shown in FIG. 6 (d), and the accumulator 7 is passed from the hydraulic circuit after the flow control valve 4 through the variable throttle 8a.
Variable flow rate from the accumulator 7
The flow rate flowing through the flow rate control valve 4 and into the hydraulic circuit after that changes as shown in FIG. That is, the boom cylinder 2
When the pressure fluctuation of the variable throttle 8a increases, the opening A of the variable throttle 8a increases and the passing flow rate increases. When the pressure fluctuation of the boom cylinder 2 decreases, the opening A of the variable throttle 8a decreases and the passing flow rate decreases. As a result, the control flow rate per unit time increases. Therefore, due to the accumulator action of the accumulator 7 and the damping action of the variable throttle 8a, the pressure fluctuation quickly becomes small as shown in FIG.
The vibration generated in the front system including is suppressed in a short time. As a result, the cycle of vibration is not lengthened and vibration is suppressed with good responsiveness. In addition, the variable throttle 8a according to the pressure fluctuation
Since the passage flow rate of the pressure changes, the peak value of the pressure can be suppressed as shown in FIG.

Therefore, according to the present embodiment, it is possible to suppress the vibration of the work device with good responsiveness, suppress the peak value of the pressure, and effectively suppress the vibration.

A second embodiment of the present invention will be described with reference to FIGS. In the figure, the same reference numerals are given to members or functions equivalent to those shown in FIGS. 1 and 3.

In FIG. 7, the vibration suppressing device of the present embodiment has a vibration suppressing circuit 100 in addition to the first embodiment shown in FIG.
Switch 20 and power source 21 as means for setting opening and closing of
have. When the switch 20 is closed (when it is on), the power supply 21 is connected to the control unit 9A, and the ON signal is given to the control unit 9A. When the switch 20 is opened (when it is off), the connection between the power source 21 and the control unit 9A is cut off, and an off signal is given to the control unit 9A.

The control unit 9A controls the opening of the variable throttle 8a based on the signals output from the pressure sensors 10a and 10b and the signal output from the switch 20 according to the flow chart of the control procedure program shown in FIG. .

First, in step 130, the switch 20
It is determined whether the switch 20 is turned on based on the above signal from, and when it is turned on, the procedure proceeds to step 131, where the control gain K
When p is set to the optimum value Ko, and when it is off, the procedure proceeds to step 132, and the control gain Kp is set to 0.

Next, in step 100, the signals from the pressure sensors 10a and 10b are input via the A / D converter 9a and stored in the RAM 9d as the head side pressure Pa of the boom cylinder 2 and the accumulator 7 side pressure Pb. . Next, in step 110, the differential pressure ΔP across the variable throttle 8a is calculated.

Next, in step 120, the absolute value of the differential pressure ΔP multiplied by an appropriate gain Kp is calculated as the flow rate command value Δq, and the corresponding flow rate command signal is output to the solenoid operating portion 8c of the variable throttle device 8. Then go back to the beginning.

In the above, the procedure 132 is the switch 2
An opening / closing unit that keeps the flow rate command value Δq at 0 when the vibration suppression circuit 100 is set to be closed by 0 (setting unit) is configured.

According to the present embodiment configured as described above,
When the switch 20 is closed, the control gain Kp
Is set to the optimum value Ko, the same vibration suppression control as that of the first embodiment can be performed, and the control gain Kp is set to 0 when the switch 20 is opened. The value Δq is kept at 0, and the conventional work without vibration suppression control can be performed.

A third embodiment of the present invention will be described with reference to FIGS. 9 and 10. In the figure, the same members or functions as those shown in FIG. 1 are designated by the same reference numerals. In this embodiment, the opening of the variable throttle is directly controlled by the differential pressure across the variable throttle.

In FIG. 9, the vibration suppressing circuit 100A includes a conduit 30a that branches from before and after the variable throttle 8a of the conduit 12,
30b, and the variable diaphragm device 8A includes the conduits 30a and 30b.
Is connected to the variable throttle 8a by the differential pressure across the variable throttle 8a.
Actuator device 3 for driving the valve body of a to adjust the opening degree
Have two.

Further, a switch 33 and a power source 34 are provided as means for setting the opening / closing of the vibration suppressing circuit 100A,
An electromagnetic opening / closing valve 35 is arranged in the pipeline 12 as opening / closing means for opening / closing the vibration suppressing circuit 100A. Switch 3
When 3 is closed, the power supply 34 is connected to the solenoid portion 35a of the electromagnetic opening / closing valve 35, and the electromagnetic opening / closing valve 35 is switched to the open position. When the switch 33 is opened, the connection between the power source 34 and the solenoid portion 35a is cut off, and the electromagnetic opening / closing valve 35 is switched to the closed position.

FIG. 10 shows the structure of the variable diaphragm device 8A.
In FIG. 10, the variable throttle device 8A includes a housing 42 in which passages 40 and 41 connected to the conduit 12 are formed,
A spool 43 slidably arranged in the housing 42
And a notch 44 serving as the variable aperture 8a is formed in the center of the spool 43. When the spool 43 is in the neutral position shown in the figure, the communication between the passages 40 and 41 is cut off, and when the spool 43 is moved to the left or right in the figure, the variable throttle 8a opens at an opening degree according to the amount of movement, and the passage 4
0, 41 communicate. In the housing 42, hydraulic chambers 45, 46 having the end surface of the spool 43 as a pressure receiving surface are formed as the actuator device 32.
46 is the passage 40, via the passages 30a and 30b,
It communicates with 41. Further, springs 49 and 50 for holding the spool 43 in the neutral position are arranged in the hydraulic chambers 45 and 46.

Hydraulic chambers 45, 4 of the actuator device 32
When the pressure in the conduit 12 is guided to the valve 6 through the passages 30a and 30b, the spool 43 moves in accordance with the differential pressure across the variable throttle 8a, that is, the pressure fluctuation in the boom cylinder 2, and the opening of the variable throttle 8a changes. Adjusted.

Therefore, also in the present embodiment, the variable throttle 8 is adjusted according to the pressure fluctuation (fluctuation component) of the boom cylinder 2.
Since the opening degree of a is adjusted, the vibration suppression control similar to that in the first embodiment can be performed.

Further, in FIG. 9, when the switch 33 is closed, the on-off valve 35 is in the open position, so that the vibration suppressing circuit 100A is opened and the vibration suppressing control is not performed as in the second embodiment. You can work as usual.

In the second embodiment, the vibration suppressing circuit 10
Although the opening / closing means for opening / closing 0 is incorporated as a part of the control program in the control unit 9A and configured by software, an opening / closing valve is arranged in the pipe line 12 as in the third embodiment.
The vibration suppression circuit may be opened and closed directly.

[0054]

According to the present invention, the vibration of the working device can be suppressed with good response, the peak value of the pressure can be suppressed, and the vibration can be suppressed effectively.

[Brief description of drawings]

FIG. 1 is a diagram showing a vibration suppressing device for a hydraulic working machine according to a first embodiment of the present invention together with a hydraulic drive circuit.

FIG. 2 is a diagram showing a configuration of a control unit of the vibration suppressing device shown in FIG.

FIG. 3 is a flowchart showing a control procedure performed by the control unit shown in FIG.

FIG. 4 is a diagram showing the action of a differential pressure across the variable throttle.

FIG. 5 is an operation lever input in a conventional vibration suppression device,
5 is a time chart showing changes over time in cylinder displacement, cylinder pressure, throttle opening, and control flow rate.

FIG. 6 is a time chart showing changes over time in the operation lever input, cylinder displacement, cylinder pressure, throttle opening, and control flow rate in the vibration suppressing device of the first embodiment shown in FIG.

FIG. 7 is a diagram showing a vibration suppressing device for a hydraulic working machine according to a second embodiment of the present invention together with a hydraulic drive circuit.

8 is a flowchart showing a control procedure performed by the control unit shown in FIG.

FIG. 9 is a diagram showing a vibration suppressing device for a hydraulic working machine according to a third embodiment of the present invention together with a hydraulic drive circuit.

10 is a flowchart showing a control procedure performed by the control unit shown in FIG.

FIG. 11 is a diagram showing a conventional vibration suppression device for a hydraulic working machine together with a hydraulic drive circuit.

[Explanation of symbols]

1 Hydraulic Pump 2 Boom Cylinder 2A Boom (Working Device) 4 Flow Control Valve 7 Accumulator (Accumulator) 8; 8A Variable Throttle Device 8a Variable Throttle 8b Spring 8c Solenoid Operating Unit 9; 9A Control Unit (Calculator) 10a, 10b Pressure Sensor (first and second pressure detecting means) 12 Pipe line 20; 33 Switch 21; 34 Power supply 32 Actuator device 35 Electromagnetic on-off valve 100; 100A Vibration suppression circuit

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Toichi Hirata Inoue Hirata, 650 Jinritsucho, Tsuchiura, Ibaraki Prefecture Tsuchiura Plant, Hitachi Construction Machinery Co., Ltd. Machinery Company Tsuchiura Factory

Claims (9)

[Claims] 1. A hydraulic pump, and a hydraulic actuator driven by pressure oil discharged from the hydraulic pump,
Connected between the hydraulic pump and the hydraulic actuator,
A vibration suppressing device for a hydraulic working machine, comprising: a flow rate control valve that controls a flow rate of pressure oil supplied to the hydraulic actuator in accordance with an operation signal from an operating means, (a) a hydraulic pressure connected to the hydraulic actuator A vibration suppressing circuit including a pressure accumulating means for energy storage and a variable throttle arranged in a conduit connecting the hydraulic actuator and the pressure accumulating means; and (b) a variable throttle depending on a differential pressure across the variable throttle. A vibration control device for a hydraulic working machine, comprising: a throttle control means for controlling an opening. 2. The vibration suppressing device for a hydraulic working machine according to claim 1, further comprising: setting means for setting opening / closing of the vibration suppressing circuit; and opening / closing means for opening / closing the vibration suppressing circuit by operating the setting means. A vibration suppressing device for a hydraulic working machine, further comprising: 3. The vibration suppressing device for a hydraulic working machine according to claim 2, wherein the opening / closing means is an opening / closing valve arranged in a pipe line connecting the hydraulic actuator and the pressure accumulating means. Vibration suppression device for work machines. 4. The vibration suppressing device for a hydraulic working machine according to claim 1, wherein the throttle control means outputs the differential pressure detection means for detecting a differential pressure across the variable throttle, and the differential pressure detection means. And a calculation means for calculating and outputting a flow rate command value based on a differential pressure signal, and the opening of the variable throttle is controlled on the basis of the flow rate command value. . 5. The vibration suppressing device for a hydraulic work machine according to claim 4, wherein the differential pressure detecting means detects a pressure in a conduit portion between the hydraulic actuator and the variable throttle. And a second pressure detecting means for detecting a pressure in a pipe line portion between the variable throttle and the pressure accumulating means. 6. The vibration suppressing device for a hydraulic work machine according to claim 4, wherein the arithmetic means obtains an absolute value of a value obtained by multiplying a differential pressure across the variable throttle by a control gain as the flow rate command value. A characteristic vibration control device for hydraulic work machines. 7. The vibration suppressing device for a hydraulic working machine according to claim 4, wherein the setting means for setting the opening and closing of the vibration suppressing circuit, and the setting when closing the vibration suppressing circuit is set by the setting means. A vibration suppressing device for a hydraulic working machine, further comprising: an opening / closing means for keeping the flow rate command value output by the computing means at zero. 8. The vibration suppressing device for a hydraulic working machine according to claim 1, wherein the throttle control means drives the valve element of the variable throttle by the differential pressure across the variable throttle to adjust the opening of the variable throttle. A vibration suppressing device for a hydraulic working machine, comprising: 9. The vibration suppressing device for a hydraulic working machine according to claim 8, wherein the variable throttle has a notch formed in a central portion of the spool, and the actuator means includes one end of the spool of the variable throttle. Vibration suppression of a hydraulic working machine, comprising: a first hydraulic chamber that applies pressure on the actuator side, and a second hydraulic chamber that applies pressure on the accumulator side of the variable throttle to the other end of the spool. apparatus.