JP2915247B2 - Vibration suppression device for hydraulic work machine - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

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

[0002]

2. Description of the Related Art As an apparatus for suppressing vibration of a hydraulic working machine, an accumulator for accumulating energy is used, as disclosed in Japanese Patent Application Laid-Open No. 64-75722, to suppress the vibration of the working apparatus during traveling of the hydraulic working machine. 2. Description of the Related Art There are known vibration suppressing devices. FIG. 7 shows a hydraulic drive circuit in which this vibration suppression device is applied to a boom drive device of a hydraulic shovel.

In FIG. 11, a hydraulic drive circuit includes a hydraulic pump 1, a boom cylinder 2 for driving a boom 2A, and a hydraulic oil supplied to the boom cylinder 2 by an operation signal of an operation lever 3 as a boom drive device. A flow control valve 4 for controlling a flow rate and an oil feeding direction, and a relief valve 5 for releasing pressurized oil to a tank 6 when a hydraulic pressure between the hydraulic pump 1 and the flow control valve 4 exceeds a predetermined value. Further, as a vibration suppressing device, an accumulator 7 for accumulating pressure connected to a pipe between the flow control valve 5 and the boom cylinder, and a fixed throttle 80 arranged in a pipe connecting the pipe to the accumulator 7 are provided. It has.

In the above hydraulic drive circuit, when pressure fluctuations corresponding to the vibrations occur in the pipeline between the boom cylinder 2 and the flow control valve 4 due to the vibration of the boom, when the pressure in the pipeline is high, the pipeline is disconnected from the pipeline. 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 from the accumulator 7 into the pipeline via the fixed throttle 80, whereby the pressure fluctuation as the vibrating force is reduced. It is reduced and vibration of the boom is suppressed.

In Japanese Utility Model Laid-Open Publication No. 64-14259, a variable throttle is arranged in place of the fixed throttle, the pressure of the hydraulic actuator is taken out via the fixed throttle, and the opening of the variable throttle is determined by the fixed throttle. It has been proposed to make adjustments according to the pressure taken out. According to this configuration, the variable component of the pressure is removed from the pressure of the hydraulic actuator by the fixed throttle, so that the opening degree of the variable throttle changes according to the steady component of the pressure of the actuator, and the weight of the working device is reduced. Even if it becomes large, the peak value of the pressure change at the time of vibration suppression does not become large, and the vibration suppression effect suitable for the load state can be obtained.

[0006]

However, FIG.
In the conventional vibration suppressing device described in Japanese Patent Application Laid-Open No. 64-75722, the pressure oil flows in and out through the fixed throttle 8, so that a sufficient vibration damping effect can be obtained even when the pressure fluctuation is large. In order to achieve this, it is necessary to set the opening of the fixed aperture 80 large, and in this case, the time until the vibration stops is long, and the responsiveness is reduced.

In the prior art described in Japanese Utility Model Laid-Open Publication No. 64-14259, the opening degree of the variable throttle is changed in accordance with the steady-state component of the pressure of the actuator, but the fluctuation component (the fluctuation component of the pressure of the actuator). Even if the pressure changes, the opening of the variable throttle does not change.In order to obtain a sufficient vibration suppression effect even when the pressure fluctuation is large, it is necessary to set the opening of the variable throttle to be large at that time. Is reduced.

Therefore, the conventional vibration suppressing device is not applied at the time of normal operation, but is only applied at the time of traveling when the response is not a problem.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a vibration suppressing device for a hydraulic working machine capable of suppressing the vibration of a working device with good responsiveness by controlling a flow rate of auxiliary pressure oil according to a pressure fluctuation of a hydraulic actuator. Is to provide.

[0010]

To achieve this object, the present invention provides a hydraulic pump, a hydraulic actuator driven by hydraulic oil discharged from the hydraulic pump,
Connected between the hydraulic pump and a hydraulic actuator,
A vibration control device for a hydraulic working machine comprising a flow control valve for controlling a flow rate of hydraulic oil supplied to the hydraulic actuator in response to an operation signal from an operation means; A vibration suppressing circuit including a pressure accumulating means for accumulating energy and a variable throttle disposed in a conduit connecting the hydraulic actuator and the pressure accumulating means; and (b) the variable throttle according to a pressure fluctuation component of the hydraulic actuator. Throttle control means for controlling the opening degree of the throttle;
It is characterized by having.

Preferably, the vibration suppressing device further comprises a setting means for setting the opening and closing of the vibration suppressing circuit, and an opening and closing means for opening and 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 pipe connecting the hydraulic actuator and the pressure accumulating means.

In the above-described vibration suppressing device, preferably, the throttle control means includes a pressure detection means for detecting a pressure of the hydraulic actuator, and a pressure detection means for detecting a pressure of the actuator based on a pressure signal output from the pressure detection means. Calculating means for calculating a variation component and calculating and outputting a flow command value based on the variation component, wherein the opening of the variable throttle is controlled based on the flow command value.

[0013] In this case, preferably, the calculating means includes a filtering means for filtering the pressure signal output from the pressure detecting means to remove a vibration component having a frequency lower than a predetermined frequency, and a filter after the filtering processing. Means for obtaining, as the flow rate command value, an absolute value of a value obtained by multiplying a high frequency component of the pressure signal by a control gain.

[0014] Preferably, the vibration suppressing device is
Setting means for setting the opening and closing of the vibration suppression circuit; and a flow command value output by the arithmetic means when the setting of the vibration suppression circuit is set to be closed.
And an opening / closing means for maintaining the pressure.

Further, in the above vibration suppressing device, the throttle control means includes a pressure detecting means for extracting a steady component of the pressure of the hydraulic actuator, and a pressure difference of the hydraulic actuator and the steady component of the pressure. Actuating means for driving a valve body to adjust the opening of the variable throttle may be provided. In this case, preferably,
The pressure detecting means is a throttle. The variable throttle has a notch formed at the center of the spool, and the actuator means has a first hydraulic chamber for applying pressure of the actuator to one end of the spool, and the other end of the spool to the other end of the spool. A second hydraulic chamber for applying a steady component of the pressure of the actuator.

[0016]

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

However, this alone sacrifices responsiveness as described above. In the present invention, vibration is suppressed with good responsiveness by controlling the opening degree of the variable throttle according to the fluctuation component of the pressure of the hydraulic actuator by the throttle control means. In other words, when the working device vibrates, the opening degree of the variable throttle increases when the fluctuation component of the pressure of the hydraulic actuator increases, and when the fluctuation component of the pressure decreases, the opening degree of the variable throttle decreases. The flow rate of the pressure oil flowing in and out through the throttle is controlled, and the control flow rate per unit time increases. For this reason, the pressure fluctuation is quickly reduced, and the vibration is suppressed with good responsiveness.

[0018]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A first embodiment of the present invention will be described below with reference to FIGS. 1 to 6 in which a hydraulic excavator is used 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 hydraulic oil discharged from the hydraulic pump 1, and is a hydraulic actuator that drives a boom 2A of a working device, for example, a hydraulic shovel, that is, a boom cylinder. A flow control valve 4 connected between the hydraulic pump 1 and the hydraulic actuator 2 and controlled by a pilot pressure signal by operating the operation lever 3 to control the flow rate of the pressure oil supplied to the hydraulic actuator 2; A relief valve 5 is provided which opens when the pressure between the pump 1 and the flow control valve 4 exceeds a set value.

The vibration suppressing device of this embodiment is provided in the hydraulic drive circuit described above, and comprises an accumulator 7 for storing hydraulic energy and an accumulator 7 from the boom cylinder 2.
A variable throttle device 8 for controlling the flow rate of the pressure oil flowing out of the compressor and the flow rate of the pressure oil flowing from the accumulator 7 to the boom cylinder 2, a control unit 9 for controlling the variable throttle device 8,
A pressure sensor 10 for detecting the pressure of the boom cylinder 2.

The accumulator 7 is connected to a pipe 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 12 connecting the pipe 11 and the accumulator 7. It has a variable throttle 8a, and the pressure sensor 10 is connected to the pipe 12 between the variable throttle 8a and the pipe 11. The variable throttle device 8 further includes a spring 8b for urging the valve body of the variable throttle 8a in the valve closing direction, and a spring 8b.
And a solenoid operating unit 8c that drives the valve body of the variable throttle 8a to adjust the opening degree. Control unit 9
Inputs a signal from the pressure sensor 10 to calculate a flow command value for suppressing vibration, and outputs a corresponding flow command signal to the solenoid operating section 8c of the variable throttle device 8. The opening degree of the variable throttle 8a of the variable throttle device 8 is controlled by the flow command signal, and the flow rate of the pressure oil flowing into and out of the accumulator 7 is controlled.

In the above description, the accumulator 7, the variable throttle 8a and the conduit 12 constitute a vibration suppressing circuit 100, and the spring 8b, the solenoid operating section 8c, the control unit 9 and the pressure sensor 10 determine the pressure of the boom cylinder (hydraulic actuator) 2. The aperture control means controls the opening of the variable aperture 8a in accordance with the fluctuation component of the aperture.

The control unit 9 comprises a microcomputer, as shown in FIG. 2, an A / D converter 9a for converting a signal output from the pressure sensor 10 into a digital signal, a central processing unit (CPU) 9b, Read-only memory (ROM) for storing control procedure programs
9c, a random access memory (RAM) 9d for temporarily storing numerical values in the middle of calculation, an I / O interface 9e for output, and an amplifier for outputting a flow rate command signal to the solenoid operating unit 8c of the variable throttle device 8. 9f.

The control unit 9 obtains a high-frequency component of the pressure on the head side of the boom cylinder 2 based on a signal output from the pressure sensor 10 and calculates the absolute value of a value obtained by multiplying the high-frequency component by a control gain to the flow command value. Asking.

Hereinafter, the operation of this embodiment will be described in detail with reference to the flowchart of the control procedure program shown in FIG. First, in step 100, a signal from the pressure sensor 10 is input via the A / D converter 9a and stored in the RAM 9d as the head side pressure P of the boom cylinder 2.

Next, in step 110, the head-side pressure P of the boom cylinder 2 is passed through a high-pass filter, and a vibration component (hereinafter referred to as a high-frequency component) Fh having a frequency equal to or higher than a predetermined frequency.
Is calculated to remove vibration components below a predetermined frequency. This is performed by using the arithmetic expression of the high-pass filter F _h = f _HPF (P) previously incorporated in the control program.

FIG. 4 shows the concept of processing the pressure P by the high-pass filter in step 110. Boom cylinder 2A
When the input u (stroke) of the operation lever 3 is changed as shown in FIG. 4A while the holding pressure of the boom cylinder 2A is 100 kg / cm ² , for example, the speed V of the boom cylinder 2A becomes
The pressure P changes as shown in FIG. 4B, and the pressure P changes as shown in FIG. That is, when the boom cylinder 2A is started and stopped, the pressure P becomes as shown in FIG. 4D due to the own weight of the boom 2A, the inertia of 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,
Accordingly, the speed V also changes as shown in FIG. When this is subjected to a high-pass filter, a vibration component having a frequency lower than a predetermined frequency is removed, and only a high-frequency component Ph associated with starting and stopping is obtained as shown in FIG. The vibration component Vh when the speed V passes through the high-pass filter is as shown in FIG. The vibration of the pressure P and the vibration of the speed V have a phase shift of 90 °.

Here, the high-frequency component Ph of the pressure after the high-pass filter matches the value obtained by removing the effect of the holding pressure from the pressure P, and corresponds to the acceleration of the boom cylinder 2 on a one-to-one basis.
That is, in the present embodiment, instead of directly detecting the acceleration that is the source of the vibrating force, the acceleration is detected by passing the pressure P through a high-pass filter and obtaining the high-frequency component Ph. Here, the predetermined frequency of the high-pass filter is preferably set to a frequency equal to or lower than the natural frequency of the working device to be controlled in consideration of the influence as the vibrating force. In this embodiment, since the working device to be controlled includes the boom 2A and the weight supported by the boom, the frequency is lower than the natural frequency of the entire boom 2A, and more specifically, depends on the size of the hydraulic shovel. Is a value generally in the range of 1 to 3 Hz.

Next, in step 120, the absolute value of a value obtained by multiplying the high-frequency component Ph of the pressure of the boom cylinder 2 by an appropriate gain Kp is calculated as a flow command value Δq, and the corresponding flow command signal is output to the variable throttle device 8. It outputs to the solenoid operation part 8c and returns to the beginning.

Next, the operation and effect of this embodiment will be described with reference to FIGS. FIG. 5 shows an input u (pilot pressure) of the operating lever 3 when the boom is suddenly stopped, in the hydraulic excavator provided with the conventional vibration suppressing device shown in FIG.
The change over time 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 where there is no vibration suppression device. In the drawing, the solid line indicates the case where there is a vibration suppression device, and the broken line indicates the case where there is no vibration suppression device.

When the operating lever 3 is returned to neutral to stop the boom 2A suddenly from the state where 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 (tilt of the cylinder displacement X) and the pressure P
The boom cylinder 2 operating in the lowering direction attempts to stop, but the boom 2A does not stop suddenly due to inertia and continues to lower beyond the target position as shown in FIG. 5 (b). 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, immediately after the displacement X of the boom cylinder 2 exceeds the target position, the pressure P increases, and accordingly the cylinder speed V becomes zero. . Thereafter, in the hydraulic circuit after the flow control valve 4, the pressure oil acts as a spring, and the boom cylinder 2 is pushed back upward, the cylinder displacement X starts increasing, the speed V changes to a positive value, and the pressure P increases. Starts to decrease. When the boom cylinder 2 is pushed back to the predetermined position, the boom cylinder 2 is similarly pushed back again by the spring action of the pressure oil, and the cylinder displacement X starts decreasing and the speed V turns to a negative value. And the pressure P starts to increase. The above is repeated, and vibration occurs in the front system including the boom 2A. This vibration is applied to the vehicle body, causing the vehicle body to swing due to the backlash of the vehicle body and the like, and as a result, coupled vibration of the entire vehicle body-front is generated.

When the conventional vibration damping 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. When the pressure oil flows out of the hydraulic circuit after the flow control valve 4 to the accumulator 7 through the fixed throttle 80 and the boom cylinder 2 is pushed back upward, the boom cylinder 2 is fixed from the accumulator 7 as shown in FIG. Pressure oil flows into the hydraulic circuit after the flow control valve 4 through the throttle 80. For this reason,
Due to the pressure accumulating 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.

Here, in the above-mentioned conventional vibration suppressing device, since the fixed aperture 80 is used, the aperture opening A of FIG.
As shown in (d), it is constant, and its opening is set large in order to obtain a sufficient vibration damping effect. For this reason, the cycle of the vibration becomes longer, the time until the vibration stops, and the responsiveness decreases.

FIG. 6 is a view similar to FIG. 5 of the hydraulic excavator provided with the vibration suppressing device of the present embodiment shown in FIG. However, FIG. 6D shows the opening A of the variable throttle 8a. This figure also shows a comparison with the case without the vibration suppressing device. In the drawing, a solid line indicates a case with the vibration suppressing device of the present embodiment, and a broken line indicates a case without the vibration suppressing device.

In the vibration suppressing device of this embodiment, the flow rate command value Δq is calculated by obtaining the high frequency component, that is, the fluctuation component of the pressure P, by passing the pressure P of the boom cylinder 2 through a high-pass filter, and calculating the flow rate command value Δq. A is controlled so that the opening degree A of the variable throttle 8a is changed according to the fluctuation of the pressure P in FIG.
The flow changes as shown in (d) and flows from the hydraulic circuit after the flow control valve 4 to the accumulator 7 via the variable throttle 8a, and flows from the accumulator 7 through the variable throttle 8a to the hydraulic circuit after the flow control valve 4. The flow rate changes as shown in FIG. That is, when the pressure fluctuation of the boom cylinder 2 increases, the opening A of the variable throttle 8a increases and the flow rate increases, and when the pressure fluctuation of the boom cylinder 2 decreases, the opening A of the variable throttle 8a decreases and the flow rate increases. And the control flow rate per hour increases as a result. Therefore, due to the pressure accumulating action of the accumulator 7 and the damping action of the variable throttle 8a, the pressure fluctuation is rapidly reduced as shown in FIG. 6C, and the vibration generated in the front system including the boom 2A is suppressed in a short time. You. as a result,
The cycle of the vibration does not become long, and the vibration is suppressed with good responsiveness. Further, since the flow rate through the variable throttle 8a changes according to the pressure fluctuation, the peak value of the pressure can be suppressed as shown in FIG.

Therefore, according to this embodiment, the vibration of the working device can be suppressed with good responsiveness, the peak value of the pressure can be suppressed, and the vibration can be suppressed effectively.

In the above-described embodiment, the high-pass filter is incorporated as a part of the control program and configured as software. However, an external high-pass filter including an electric circuit may be used. In this case, the detection signal may be input to the external high-pass filter, and the processed high-frequency component Ph may be input to the control unit to determine the flow rate command value Δq.

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.

In FIG. 7, the vibration suppressing device of this embodiment is different from the first embodiment shown in FIG.
Switch 20 and power supply 21
have. When the switch 20 is closed (when turned on), the power supply 21 is connected to the control unit 9A, and an ON signal is given to the control unit 9A. When the switch 20 is opened (when it is off), the connection between the power supply 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 signal output from the pressure sensor 10 and the signal output from the switch 20, according to the flowchart of the control procedure program shown in FIG.

First, in step 130, the switch 20
It is determined whether or not the switch 20 is on based on the above signal from.
p is set to the optimum value Ko, and when it is off, the routine proceeds to step 132, where the control gain Kp is set to zero.

Next, in step 100, a signal from the pressure sensor 10 is input via the A / D converter 9a, and the signal is input to the RAM 9 as the head side pressure P of the boom cylinder 2.
Stored in d.

Next, in step 110, the pressure P on the head side of the boom cylinder 2 is passed through a high-pass filter, and a vibration component (hereinafter, referred to as a high-frequency component) Ph of a predetermined frequency or more is Ph.
Is calculated.

Next, in step 120, the absolute value of a value obtained by multiplying the high frequency component Ph of the pressure of the boom cylinder 2 by an appropriate gain Kp is calculated as a flow command value Δq, and the corresponding flow command signal is output to the variable throttle device 8. It outputs to the solenoid operation part 8c and returns to the beginning.

In the above, the procedure 132 corresponds to the switch 2
An opening / closing unit that maintains the flow command value Δq at 0 when 0 (setting unit) sets the closing of the vibration suppression circuit 100 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 in the first embodiment can be performed. When the switch 20 is open, the control gain Kp is set to 0, so that the flow rate command The value Δq is kept at 0, and the conventional work without performing the vibration suppression control can be performed.

A third embodiment of the present invention will be described with reference to FIGS. In the drawing, the same reference numerals are given to members or functions equivalent to those shown in FIG. In this embodiment, the opening degree of the variable throttle is directly controlled by the pressure fluctuation of the hydraulic actuator.

In FIG. 9, a pipe 30 branches from the pipe 12 of the vibration suppression circuit 100A, and a fixed throttle 31 is provided in the middle of the pipe 30. The fixed throttle 31 functions as pressure detecting means for extracting a steady component of the pressure of the boom cylinder 2 (hydraulic actuator). Variable aperture device 8A
The variable throttle 8a is disposed in the pipeline 12 on the accumulator 7 side from the branch position of the pipeline 30. The variable aperture device 8A is connected to the conduit 30 before and after the fixed aperture 31,
An actuator device 32 is provided which drives the valve body of the variable throttle 8a to adjust the opening by the differential pressure between the pressure of the boom cylinder 2 and the steady component of the pressure. The fixed throttle 31 and the actuator device 32 constitute a throttle control means for controlling the opening of the variable throttle 8a in accordance with the fluctuation component of the pressure of the boom cylinder (hydraulic actuator) 2.

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

FIG. 10 shows the structure of the variable throttle device 8A, the pipeline 30 and the fixed throttle 31. In FIG. 10, the variable throttle device 8A includes passages 40 and 4 connected to the pipeline 12.
1 has a housing 42 and a spool 43 slidably disposed in the housing 42. A notch 44 serving as a variable throttle 8a is formed in the center of the spool 43. When the spool 43 is at the neutral position in the figure, the communication between the passages 40 and 41 is interrupted. When the spool 43 is moved to the left or right in the figure, the variable throttle 8a opens at an opening corresponding to the amount of movement, and the passage 40 , 41 communicate. Hydraulic chambers 45 and 46 having the end face of the spool 43 as a pressure receiving surface are formed in the housing 42 as the actuator device 32, and the hydraulic chambers 45 and 46 communicate with the passage 40 via the passages 47 and 48, respectively. I have. Passage 4
8 corresponds to the conduit 30 in FIG.
1 is provided. Further, springs 49, 50 for holding the spool 43 at the neutral position are arranged in the hydraulic chambers 45, 46.

The pressure of the boom cylinder 2 is guided to the hydraulic chamber 45 of the actuator device 32 via the passages 40 and 47, and the pressure of the boom cylinder 2 is transmitted to the hydraulic chamber 46 via the passages 40 and 48 (30) and the fixed throttle 31. Is derived, the spool 43 moves according to the fluctuation component of the pressure of the boom cylinder 2, that is, the fluctuation of the pressure of the boom cylinder 2, and the opening of the variable throttle 8a is adjusted.

Therefore, also in this embodiment, the combination of the fixed throttle 31 and the actuator device 32 causes the variable throttle 8 to respond to the pressure fluctuation (fluctuation component) of the boom cylinder 2.
Since the opening of a is adjusted, the same vibration suppression control as in the first embodiment can be performed.

In FIG. 9, when the switch 33 is closed, the on-off valve 35 is in the open position, so that the vibration suppression circuit 100A is opened, and the vibration suppression control is not performed as in the second embodiment. Work can be done as usual.

In the second embodiment, the vibration suppression circuit 10
Opening / closing means for opening / closing 0 is incorporated as a part of a control program in the control unit 9A, and is configured as software. However, as in the third embodiment, an opening / closing valve is disposed in the pipeline 12;
The opening and closing of the vibration suppression circuit may be performed directly.

[0055]

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

[Brief description of the drawings]

FIG. 1 is a diagram showing a vibration suppression 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 suppression 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 illustrating the operation of a high-pass filter.

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

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

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

FIG. 8 is a flowchart showing a control procedure performed by the control unit shown in FIG. 7;

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

FIG. 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]

 Reference Signs List 1 hydraulic pump 2 boom cylinder 2A boom (working device) 4 flow control valve 7 accumulator (pressure accumulating means) 8; 8A variable throttle device 8a variable throttle 8b spring 8c solenoid operating section 9; 9A control unit (computing means) 10 pressure sensor ( Pressure detecting means) 12 conduit 20; 33 switch 21; 34 power supply 31 fixed throttle 32 actuator device 35 solenoid on-off valve 100; 100A vibration suppression circuit

──────────────────────────────────────────────────の Continuing on the front page (72) Inventor Toichi Hirata 650 Kandamachi, Tsuchiura-shi, Ibaraki Pref.Hitachi Construction Machinery Co., Ltd. (56) References JP-A-64-75722 (JP, A) JP-A-60-245801 (JP, A) JP-A-3-244720 (JP, A) JP-A-56-80508 ( JP, A) JP-A 14-14259 (JP, U) JP-A 2-66867 (JP, U) (58) Fields investigated (Int. Cl. ⁶ , DB name) F15B 11/00-11/22 E02F 9/22

Claims (9)

(57) [Claims] 1. A hydraulic pump, a hydraulic actuator driven by pressure oil discharged from the hydraulic pump,
Connected between the hydraulic pump and a hydraulic actuator,
A flow control valve for controlling the flow rate of hydraulic oil supplied to the hydraulic actuator in response to an operation signal from an operation means; A vibration suppression circuit including a pressure accumulating means for accumulating energy and a variable throttle disposed in a pipeline connecting the hydraulic actuator and the pressure accumulating means; and (b) the variable throttle according to a pressure fluctuation component of the hydraulic actuator. And a throttle control means for controlling an opening of the hydraulic work machine. 2. A vibration suppression device for a hydraulic work machine according to claim 1, wherein said setting means sets the opening and closing of said vibration suppression circuit, and said opening and closing means opens and closes said vibration suppression circuit by operating said setting means. A vibration suppression device for a hydraulic working machine, further comprising: 3. The apparatus according to claim 2, wherein said opening / closing means is an opening / closing valve disposed in a conduit connecting said hydraulic actuator and said pressure accumulating means. Vibration suppression device for work machines. 4. The vibration control device for a hydraulic working machine according to claim 1, wherein the throttle control unit is configured to detect a pressure of the hydraulic actuator and a pressure signal output from the pressure detection unit. Calculating means for calculating a fluctuation component of the pressure of the actuator, calculating and outputting a flow command value based on the fluctuation component, wherein the opening of the variable throttle is controlled based on the flow command value. A vibration suppression device for a hydraulic working machine, characterized in that: 5. The vibration control device for a hydraulic working machine according to claim 4, wherein said calculation means performs a filtering process on the pressure signal output from said pressure detection means to remove a vibration component having a frequency lower than a predetermined frequency. And a means for obtaining, as the flow rate command value, an absolute value of a value obtained by multiplying a high frequency component of the pressure signal subjected to the filter processing by a control gain, as the flow rate command value. 6. A vibration suppressing device for a hydraulic working machine according to claim 4, wherein said setting means sets opening and closing of said vibration suppressing circuit, and said setting means sets said closing and closing of said vibration suppressing circuit when said setting means closes said vibration suppressing circuit. A vibration suppression device for a hydraulic working machine, further comprising: opening and closing means for keeping a flow command value output by the calculation means at zero. 7. The vibration suppressing device for a hydraulic working machine according to claim 1, wherein the throttle control means includes a pressure detecting means for extracting a steady component of the pressure of the hydraulic actuator, a pressure of the hydraulic actuator and a steady component of the pressure. Actuator means for driving the valve element of the variable throttle by adjusting the pressure difference between the variable throttle and the opening degree of the variable throttle. 8. The vibration suppressing device for a hydraulic working machine according to claim 7, wherein said pressure detecting means is a throttle. 9. The vibration suppressing device for a hydraulic working machine according to claim 7, wherein the variable throttle has a notch formed at a center portion of a spool, and the actuator means has a pressure of the actuator at one end of the spool. And a second hydraulic chamber for applying a steady-state component of the pressure of the actuator to the other end of the spool.