JP2010133471A - Accumulator control device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To reduce noise caused by a hydraulic pulse of an oil pump in a working machine such as a hydraulic excavator. <P>SOLUTION: An accumulator control device 18 is equipped with a hydraulic cylinder 14 and a cylinder block which forms a rotary shaft rotatably arranged and a plurality of cylinder separating in circumferential direction from the rotary shaft and extending in axial direction, and rotates integrally with the rotary shaft. Furthermore, the control device is installed on a working machine which has a hydraulic pump 12 supplying a hydraulic fluid driving the hydraulic cylinder 14 and an accumulator 17 connected with a discharging port of this hydraulic pump 12 through an opening/closing valve 16, and controls a pressure accumulation movement of the accumulator 17 by the opening/closing valve 16. An opening/closing valve control means 18C is provided to control the opening/closing valve 16 to an opening condition when a sound pressure level of the noise within a cab box 9 exceeds a predetermined threshold value. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to an accumulator control device that is provided in a hydraulic circuit of a work machine such as a hydraulic excavator and reduces hydraulic pulsation generated in a hydraulic pipeline.

  Generally, an accumulator includes a gas chamber in which a compressible gas, for example, nitrogen gas is sealed at a predetermined sealing pressure, and an oil chamber in which hydraulic oil is accumulated. The gas chamber and the oil chamber are partitioned by a movable or deformable partition, and the oil chamber is provided with a port so that hydraulic oil can flow in and out. When the high pressure hydraulic oil flows into the oil chamber from this port, the partition wall moves or deforms, the gas in the gas chamber is compressed, and the compression energy is accumulated.

  One of the purposes of providing an accumulator in a hydraulic circuit of a work machine is to absorb hydraulic pulsation generated by a hydraulic pump. A hydraulic pump used in a work machine has a structure in which a plurality of cylinders extending in the axial direction are formed at equal intervals in a cylinder block that rotates integrally with a rotating shaft driven by an engine. Since the pump action is realized by sequentially sucking and discharging the hydraulic oil as the cylinder block rotates, the discharge pressure of the hydraulic oil fluctuates regularly. This regular pressure fluctuation has a constant frequency, and this pressure fluctuation is a hydraulic pulsation. The influence of hydraulic pulsation extends to a hydraulic actuator such as a hydraulic cylinder to which hydraulic oil is supplied. In the prior art aimed at reducing hydraulic pulsation, a configuration is used in which an accumulator is provided via an on-off valve in parallel with the hydraulic actuator for the pipeline connecting the discharge port of the hydraulic pump and the bottom side of the actuator, for example. It has been.

  The minimum operating pressure and the maximum operating pressure of the accumulator are uniquely determined from physical conditions such as the amount and pressure of the compressible gas sealed in the gas chamber and the structure and strength of the gas chamber and the partition wall. When the hydraulic oil pressure is lower than the minimum operating pressure, if the hydraulic oil pressure is lower than the gas sealing pressure, the gas is expanded, so that the partition wall may be moved or deformed, and the partition wall may be damaged. Also, if the hydraulic fluid is higher than the maximum operating pressure, this should be avoided because the partition wall may be damaged by excessive pressure.

In order to solve the above problem, the on-off valve interposed in the configuration in which the hydraulic pump and the accumulator are connected is controlled so that the on-off valve is closed when the pressure in the pipe line is equal to or higher than the upper limit or lower limit of the preset pressure. Thus, a technique for avoiding breakage of the partition walls is known (see, for example, Patent Document 1). Here, the upper limit is set lower than the physical maximum operating pressure, and the lower limit is set higher than the physical minimum operating pressure, thereby preventing an excessive or excessive pressure from acting on the accumulator. For example, when the maximum operating pressure of the accumulator is 38 MPa and the minimum operating pressure is 8 MPa, the set pressure for the on-off valve control is set at an upper limit of 35 MPa and a lower limit of 10 MPa, and is set with a certain margin. .
Japanese Utility Model Publication No. 4-73058

  In the above-described prior art, the operation of the on-off valve is determined based on the pressure set value set within the operable pressure range of the accumulator. Therefore, the following problems occur.

  That is, for example, when the work machine is a hydraulic excavator, the hydraulic pulsation of the hydraulic pump is remarkably recognized by an operator operating in the operating room of the work machine, such as a boom, an arm, or a bucket driven by a hydraulic actuator. This is a case where noise is generated by resonance due to hydraulic pulsation during driving. Noise due to this resonance, for example, the boom tends to resonate with the fundamental wave of hydraulic pulsation, but the arm tends to resonate with the second harmonic of the fundamental wave. In particular, in the case of a hydraulic cylinder, there is a low correlation with the change in the static pressure in the hydraulic line of the hydraulic pump, such as the resonance mode of the structural member driven by the expansion / contraction state also changing. Many work machines are equipped with variable displacement hydraulic pumps. In this case, the ratio between the fundamental wave and the harmonics of the hydraulic pulsation varies depending on the capacity. Thus, the noise due to resonance has a low correlation with the change in the static pressure in the hydraulic pipeline, and particularly the noise in the hydraulic pipeline is generated even when the static pressure in the hydraulic pipeline is low. There is a limit to noise reduction in on-off valve control according to the above.

  The present invention has been made in view of the above-described problems of the prior art, and an object of the present invention is to provide an accumulator control device that can effectively reduce noise caused by hydraulic pulsation in accordance with operating conditions. .

  In order to achieve this object, in the accumulator control device according to the present invention, a hydraulic actuator and a rotary shaft provided rotatably are formed with a plurality of cylinders extending in the axial direction and spaced apart in the circumferential direction. A hydraulic pump that supplies hydraulic oil that drives the hydraulic actuator, and an accumulator connected via a discharge port of the hydraulic pump and an opening / closing valve. In the accumulator control device that controls the pressure accumulating operation of the accumulator by the on-off valve, provided is an on-off valve control means for controlling the on-off valve in an open state when a sound pressure level of noise in the cab exceeds a predetermined threshold value. It is characterized by.

  In the present invention configured as described above, the on-off valve is opened when the sound pressure level of noise in the cab exceeds a predetermined threshold regardless of the pressure in the hydraulic pipeline, so that the accumulator is removed from the hydraulic pump. The noise caused by hydraulic pulsation of the hydraulic pump is reduced. For the purpose of reducing noise caused by hydraulic pulsation, the sound pressure level of noise caused by hydraulic pulsation is detected without indirectly detecting the magnitude of the noise as pressure in the pipeline and controlling the on-off valve. As a result, it is possible to control the on-off valve in accordance with the operating state of the work machine.

  Further, in the accumulator control device according to the present invention, the on-off valve control device sets the pressure in the pipe line connecting the hydraulic pump and the on-off valve to be higher than the minimum operating pressure of the gas chamber of the accumulator. When the pressure in the hydraulic line is between the lower limit value and the minimum operating pressure of the gas chamber of the accumulator, the noise in the cab is controlled when the pressure in the hydraulic line is between the lower limit value and the minimum operating pressure. When the sound pressure level exceeds the predetermined threshold, the on-off valve is controlled to be opened.

  In the present invention configured as described above, in the control in which the on-off valve is opened when the noise in the cab exceeds a predetermined threshold value, the pressure is higher than the lower limit set higher than the minimum operating pressure of the gas chamber of the accumulator. If the pressure in the pipeline is between the lower limit value and the minimum operating pressure, the sound pressure level of the noise in the cab exceeds the predetermined threshold value. In such a case, by controlling the on-off valve to the open state, it is possible to effectively utilize the margin between the lower limit value and the minimum operating pressure, thereby expanding the open operation range of the on-off valve.

  In the accumulator control device according to the present invention, the on-off valve control means controls the on-off valve to be closed when the hydraulic pump is stopped. In the present invention configured as described above, the accumulator communicates with the pipe line while the hydraulic pump that is rotationally driven by the engine is stopped, that is, when the work vehicle is stopped. Can be prevented.

  Further, in the accumulator control device according to the present invention, the on-off valve control means includes a noise detection means for detecting noise in the cab, and the number of rotations per second of the hydraulic pump or an engine for driving the hydraulic pump Is the product of the number of rotations per second and the number of cylinders built in the cylinder block of the hydraulic pump as the fundamental frequency, and the fundamental and the harmonic that is an integral multiple of the fundamental are An extraction means for extracting from the spectrum of the noise, and for each of the sound pressure levels of the noise components extracted by the extraction means, an independent threshold is set, and at least one of the fundamental wave and the harmonic wave is When the threshold value of each sound pressure level is exceeded, the on-off valve is controlled to be opened.

  In the present invention configured as described above, the frequency f (Hz) of pulsation generated in the pressure oil discharged from the hydraulic pump is determined by the number of pistons in the cylinder block of the hydraulic pump being n and the rotation of the hydraulic pump per second. If the number is N, the frequency of the fundamental wave is 1, and the frequency order is i (i = 1, 2, 3,...), It can be expressed as f = n × N × i (Hz). If the number is obtained, the noise component due to the hydraulic pulsation generated at these frequencies is extracted from the spectrum of the entire noise including other environmental noise obtained from the noise detection means by a simple calculation based on the above formula. By setting a threshold for the sound pressure level independently for each of the fundamental wave and harmonics for noise caused by hydraulic pulsation, there is no risk of malfunction due to noise having other frequency components, with high accuracy. It becomes possible to control the on-off valve.

  In the accumulator control device according to the present invention, the on-off valve is an electromagnetic proportional valve. In the present invention configured as described above, since the opening degree of the on-off valve can be varied, the amount of hydraulic oil supplied to the accumulator can be adjusted, so that the operation of the accumulator can be made efficient.

  The present invention includes a hydraulic actuator and a cylinder block that is formed with a plurality of cylinders extending in the axial direction and spaced apart from a rotating shaft that is rotatably provided, and that rotates integrally with the rotating shaft. In an accumulator control device that is provided in a work machine having a hydraulic pump that supplies hydraulic oil to be supplied and an accumulator connected via a discharge port of the hydraulic pump and an on-off valve, and that controls an accumulator pressure accumulation operation by the on-off valve, When the noise in the cab exceeds a predetermined threshold, an on-off valve control means is provided to control the on-off valve to open, so that noise caused by hydraulic pulsation of the hydraulic pump is detected as pressure in the pipeline. It is possible to control the operation of the accumulator according to the sound pressure level of the noise in the cab that actually occurs. The noise caused by the movement can be reduced to adapt to operational status. Thereby, the noise which becomes obstructive of an operator's operation can be reduced compared with the past.

  Hereinafter, the best mode for carrying out an accumulator control device according to the present invention will be described with reference to the drawings.

  FIG. 1 is a side view of a hydraulic excavator provided with an embodiment of an accumulator control device according to the present invention. The hydraulic excavator shown in FIG. 1 includes a traveling body 1, a revolving body 2 provided on the traveling body 1 so as to be capable of turning, a boom 4 provided on a front portion of the revolving body 2 by a boom cylinder 3, and An arm 6 is rotatably connected to the tip of the boom 4 by an arm cylinder 5, and a bucket 8 is rotatably connected to the tip of the arm 6 by a bucket cylinder 7. Further, the hydraulic excavator has a cab specification. In addition, a sealed cab box 9 serving as a cab is provided. Since the boom 4, the arm 6, and the bucket 8 are respectively connected to the boom cylinder 3, the arm cylinder 5, and the bucket cylinder 7, for example, pulsation of hydraulic oil supplied to the boom cylinder 5 from a hydraulic pump 12 to be described later causes the boom 4 to move. Resonates and generates noise. The arm 6 and the bucket 8 generate noise in the same manner, but each resonance mode has a different ratio between the fundamental frequency and an integer multiple of the fundamental frequency, and varies depending on the operating condition. In the embodiment shown in FIG. 1, a microphone 20 serving as noise detection means is provided in a cab box 9 serving as a cab. The microphone 20 may be provided not in the cab box 9 but in the engine room 10 at the rear of the revolving unit 2. In that case, an air cooling fan or a water cooling pump (not shown) provided in the engine room 10 is used. In spite of the fact that it rotates independently of the engine 11 and the hydraulic pump 12 described later, it may happen to rotate at the same frequency, and if the microphone 20 picks up the noise, it will cause a malfunction when controlling the accumulator 17 described later. Therefore, the microphone 20 is preferably provided in the cab box 9.

  FIG. 2 is a block diagram showing a main configuration of an embodiment including an accumulator control device according to the present invention. In the present embodiment, an engine 11, a hydraulic pump 12, a direction switching valve 13 and a hydraulic cylinder 14 provided in the engine room 10 shown in FIG. 1 are provided. An actual hydraulic excavator includes a plurality of hydraulic actuators and hydraulic pumps that are hydraulic cylinders or hydraulic motors. In FIG. 2, the boom cylinder 3, the arm cylinder 5, the bucket cylinder 7 and the like shown in FIG. The hydraulic cylinder 14 and the hydraulic pump 12 constituting a single hydraulic circuit are simplified. Further, as a hydraulic pulsation reduction mechanism, an on-off valve 16, an accumulator 17, and an accumulator control device 18 are provided. The accumulator control device 18 includes pressure detection means 18A, set pressure input means 18B, electromagnetic valve control means 18C, pulsation component extraction means 18D, and sound pressure threshold value input means 18E. A pressure sensor 19 is connected to the pressure detection means 18A, and a microphone 20 and an electronic control unit (hereinafter referred to as ECU) 21 which are noise detection means are connected to the pulsation component extraction means 18D. The microphone 20 is provided in the cab box 9 as shown in FIG.

  First, the basic operation will be described. The engine 11 rotates and drives a hydraulic pump 12 directly connected to the rotary shaft, and hydraulic oil discharged by the hydraulic pump 12 is supplied to, for example, the rod side chamber of the hydraulic cylinder 14 via the direction switching valve 13 and is discharged from the bottom side chamber. The hydraulic fluid is guided to the tank 15. As shown in FIG. 2, the hydraulic pump 12 is connected not only to the hydraulic cylinder 14 but also to the accumulator 17 via the on-off valve 16, and the communication state to the accumulator 17 is controlled by opening and closing the on-off valve 16. Thus, the hydraulic pulsation of the hydraulic pump 12 is reduced.

  The on-off valve 16 is connected to electromagnetic valve control means 18 </ b> C built in the accumulator control device 18, whereby the communication state of the accumulator 17 is controlled. In the present embodiment, the on-off valve 16 uses an electromagnetic proportional valve, and the opening degree can be varied, but this does not preclude the use of an on / off valve with a fixed opening degree.

  Further, the accumulator control device 18 incorporates pressure detection means 18A into which a signal from a pressure sensor 19 for detecting the pressure in the hydraulic line between the hydraulic pump 12 and the direction switching valve 13 is read. Here, since the accumulator control device 18 is provided with the set pressure input means 18B for setting the pressure range for operating the accumulator 17, it is possible to open and close with the safety margin in mind by inputting the set lower limit value and the set upper limit value. The operating range of the valve 16 can be set. The pressure detection means 18A monitors the pressure every moment and transmits pressure information necessary for controlling the on-off valve 16 to the electromagnetic valve control means 18C as an electrical signal.

  Further, the accumulator control device 18 has a built-in pulsation component extracting means 18D for reading the noise spectrum in the cab box 9 measured by the microphone 20, and an engine speed signal from the ECU 21 mounted on the engine 11 is also read here. . Although the frequency of noise due to hydraulic pulsation originally depends on the rotational speed of the pump, the hydraulic pump 12 used in the work machine is directly connected to the engine 11 as shown in FIG. 2, so the engine rotational speed is replaced with the rotational speed of the pump. In general, since the engine is preliminarily provided with the control ECU 21, it is convenient to use the detection signal from the ECU 21, but by providing an independent rotation sensor, the rotational speed of the hydraulic pump 12 can be directly adjusted. It may be detected. The pulsation component extraction means 18D calculates the fundamental and harmonic frequencies of the hydraulic pulsation from the read engine speed and the predetermined number of cylinders in the cylinder block of the hydraulic pump 12, and calculates components corresponding to these frequencies. Extracted from the noise spectrum obtained from the microphone 20. The extracted sound pressure level of each component is transmitted as noise information necessary for controlling the on-off valve 16 together with the engine speed to the electromagnetic valve control means 18C in the form of an electric signal. Further, the accumulator control device 18 is provided with sound pressure threshold value input means 18E for setting a threshold value of the sound pressure level of noise for operating the accumulator 17, and is independent for each of the fundamental wave and the harmonic wave of the noise caused by the hydraulic pulsation. The threshold of the sound pressure level can be set.

  FIG. 3 is a flowchart showing a processing procedure related to the control of the accumulator control device 18 according to the present invention. First, in step S1 after the start, the pulsating component extraction means 18D reads the rotational speed of the engine 11 measured by the ECU 21. Thereafter, the process proceeds to step S2, and the solenoid valve control means 18C determines whether or not the engine 11 is stopped based on the read rotational speed.

  If the electromagnetic valve control means 18C determines in step S2 that the engine 11 is stopped, the process proceeds to step S14, and the electromagnetic valve control means 18C sends a “close” signal for closing the valve to the on-off valve 16. . After that, returning to the start, the procedure from step S1 is repeated again.

  If the solenoid valve control means 18C determines in step S2 that the engine 11 is rotating, the process proceeds to step S3, and the pressure detection means 18A reads the pressure in the pipe line from the pressure sensor 19. Thereafter, the process proceeds to step S4, and the solenoid valve control means 18C determines whether or not the read pressure is equal to or higher than the set upper limit value of the accumulator 17.

  When it is determined in step S4 that the pressure is equal to or higher than the set upper limit value of the accumulator 17, the process proceeds to step S14, and the solenoid valve control means 18C sends a “close” signal for closing the valve to the on-off valve 16. After that, returning to the start, the procedure from step S1 is repeated again.

  When the solenoid valve control means 18C determines in step S4 that the pressure does not reach the set upper limit value of the accumulator 17, the process proceeds to step S5, where the solenoid valve control means 18C sets the set lower limit value for operating the accumulator 17. Judge whether it is above.

  In Step S5, when the solenoid valve control means 18C determines that the pressure is equal to or higher than the set lower limit value for operating the accumulator 17, the process proceeds to Step S13, and the solenoid valve control means 18C opens the valve with respect to the on-off valve 16. Send an “open” signal. After that, returning to the start, the procedure from step S1 is repeated again.

  Next, when the solenoid valve control means 18C determines in step S5 that the pressure does not reach the set lower limit value for operating the accumulator 17, the process proceeds to step S6, where the solenoid valve control means 18C determines that the pressure is the lowest of the accumulator 17. Determine if it is above the operating pressure.

  When the solenoid valve control means 18C determines in step S6 that the pressure does not reach the minimum operating pressure of the accumulator 17, the process proceeds to step S14, and the solenoid valve control means 18C closes the valve with respect to the on-off valve 16. Send a “closed” signal. After that, returning to the start, the procedure from step S1 is repeated again.

  In step S6, when the solenoid valve control means 18C determines that the pressure is equal to or higher than the minimum operating pressure of the accumulator 17, the process proceeds to step S7, and the pulsation component extraction means 18D performs the engine speed obtained in step S1, that is, the pump From the rotation speed and the predetermined number of pistons in the cylinder block of the hydraulic pump 12, the fundamental and harmonic frequencies of the noise caused by the hydraulic pulsation are calculated, and then the process proceeds to step S8.

  Next, in step S8, the noise spectrum is read from the microphone 20 in the pulsation component extraction means 18D, and in the next step S9, frequency components corresponding to the fundamental wave and the harmonics of the hydraulic pulsation obtained in step S7 are obtained in step S8. Extract from the noise spectrum. Thereafter, the process proceeds to step S10, and the electromagnetic valve control means 18C determines whether or not the sound pressure level in the fundamental wave is equal to or higher than the set threshold value among the noise caused by the hydraulic pulsation extracted in step S9.

  In step S10, when the electromagnetic valve control means 18C determines that the sound pressure level in the fundamental wave among the noise due to hydraulic pulsation is equal to or higher than the set threshold value, the process proceeds to step S13, and the electromagnetic valve control means 18C In response, send an “open” signal to open the valve. After that, returning to the start, the procedure from step S1 is repeated again.

  If the electromagnetic valve control means 18C determines in step S10 that the sound pressure level in the fundamental wave of the noise caused by hydraulic pulsation does not reach the set threshold value, the process proceeds to step S11, where the electromagnetic valve control means 18C It is determined whether or not the sound pressure level at the second harmonic among the noise caused by the hydraulic pulsation extracted in step S9 is equal to or higher than a set threshold value.

  In step S11, when the solenoid valve control means 18C determines that the sound pressure level at the second harmonic of the noise caused by hydraulic pulsation is equal to or higher than the set threshold value, the process proceeds to step S13, where the solenoid valve control means 18C Send an “open” signal to 16 to open the valve. After that, returning to the start, the procedure from step S1 is repeated again.

  If the electromagnetic valve control means 18C determines in step S11 that the sound pressure level at the second harmonic of the noise caused by hydraulic pulsation does not reach the set threshold value, the process proceeds to step S12, where the electromagnetic valve control means 18C Next, it is determined whether or not the sound pressure level at the higher order N-order harmonic of the noise caused by the hydraulic pulsation extracted at step S9 is equal to or higher than a set threshold value. The harmonics to which this series of determinations are performed may be limited by the processing capability of the pulsating component extraction means 18D. In general, however, it is possible to reduce noise by targeting up to the third harmonic. It is enough.

  If the electromagnetic valve control means 18C determines in step S12 that the sound pressure level in the Nth harmonic is equal to or higher than the set threshold value among the noise caused by the hydraulic pulsation extracted in step S9, the process proceeds to step S13, and the electromagnetic valve control is performed. The means 18C sends an “open” signal to the on-off valve 16 to open the valve. With this control, a series of processing relating to the sound pressure level of the noise ends, and then the process returns to the start and the procedure from step S1 is repeated again.

  On the other hand, when the solenoid valve control means 18C determines in step S12 that the sound pressure level in the Nth harmonic does not satisfy the set threshold value among the noise caused by the hydraulic pulsation extracted in step S9, the process proceeds to step S14. The electromagnetic valve control means 18C sends a “closed” signal for closing the valve to the on-off valve 16. With this control, a series of processing relating to the sound pressure level of the noise ends, and then the process returns to the start and the procedure from step S1 is repeated again. Depending on the noise of the work machine, for example, harmonics from the third order to the fifth order of the fundamental wave may be a target for determining that the on-off valve is “open”.

  This series of controls has the following effects. First, the pulsation component extraction means 18D monitors the engine speed, and when the engine is not rotating, the electromagnetic valve control means 18C controls the on-off valve 16 to close. The on-off valve 16 is opened and the accumulator 17 does not operate. Further, the pressure detection means 18A monitors the pressure in the pipe line, and when the pressure is equal to or higher than the set upper limit value, the electromagnetic valve control means 18C controls to close the on-off valve 16, so that the accumulator 17 is excessively pressurized. Will not be damaged. Conversely, when the pressure is less than the set upper limit value, the electromagnetic valve control means 18C controls to open the on-off valve 16, so that the accumulator 17 operates to reduce the hydraulic pulsation, thereby reducing noise. The However, even if the pressure in the pipe line does not reach the set upper limit value, if the pressure does not reach the minimum operating pressure, the electromagnetic valve control means 18C is controlled so as to close the on-off valve 16, so the accumulator 17 is damaged by an excessive pressure. Never do.

  Further, even when the pressure in the pipe line is equal to or lower than the set lower limit value, if the pressure is equal to or higher than the minimum operating pressure, the electromagnetic valve control means 18C controls to open the on-off valve 16, so that the accumulator 17 operates and hydraulic pulsation By reducing the noise, noise is reduced. This control makes it possible to operate the accumulator 17 even in a pressure range that could not be operated by the prior art, and noise due to hydraulic pulsation can be reduced.

  In the accumulator control device configured as described above, the noise generation behavior of the work machine in operation is constantly monitored, so that the margin between the set lower limit value and the minimum operating pressure is effectively used to open the on-off valve 16. The range can be expanded, and noise reduction adapted to fluctuations in the sound pressure level and frequency components of noise can be achieved.

It is a side view showing a hydraulic excavator cited as an example of a work machine provided with an embodiment of an accumulator control device according to the present invention. It is a block diagram which shows the main structures of one Embodiment containing the accumulator control apparatus which concerns on this embodiment with which the hydraulic shovel shown in FIG. 1 is equipped. It is a flowchart which shows the process sequence of the accumulator control apparatus which concerns on this embodiment.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Traveling body 2 Revolving body 3 Boom cylinder 5 Arm cylinder 7 Bucket cylinder 9 Cab box (operating room)
DESCRIPTION OF SYMBOLS 10 Engine room 11 Engine 12 Pump 14 Hydraulic cylinder 16 On-off valve 17 Accumulator 18 Accumulator controller 18A Pressure detection means 18B Set pressure input means 18C Electromagnetic valve control means 18D Pulsation component extraction means 18E Sound pressure threshold value input means 19 Pressure sensor 20 Microphone ( Noise detection means)
21 Electronic control unit (ECU)

Claims (5)

A hydraulic actuator;
A plurality of cylinders extending in the axial direction and spaced apart from a rotating shaft provided in a circumferential direction are formed, and a cylinder block that rotates integrally with the rotating shaft is provided, and hydraulic oil that drives the hydraulic actuator is supplied In an accumulator control device that is provided in a work machine having a hydraulic pump, an accumulator connected to the discharge port of the hydraulic pump via an on-off valve, and an operator's cab, and that controls the pressure accumulation operation of the accumulator by the on-off valve,
An accumulator control device comprising an on-off valve control means for controlling the on-off valve to open when a sound pressure level of noise in the cab exceeds a predetermined threshold value. The accumulator control device according to claim 1,
The on-off valve control means is configured to switch the on-off valve when a pressure in a pipe line connecting the hydraulic pump and the on-off valve is higher than a lower limit value set higher than a minimum operating pressure of a gas chamber of the accumulator. When the sound pressure level of the noise in the cab exceeds the predetermined threshold value, the on-off valve is controlled to be opened when it is between the lower limit value and the minimum operating pressure. An accumulator control device. The accumulator control device according to claim 2,
The on-off valve control means controls the on-off valve to a closed state when the hydraulic pump is stopped. The accumulator control device according to claim 1,
The on-off valve control means includes a noise detecting means for detecting noise in the cab, a rotational speed per second of the hydraulic pump or a rotational speed per second of an engine driving the hydraulic pump, and the hydraulic pump An extraction means for extracting the fundamental wave and a harmonic having a frequency that is an integral multiple of the fundamental wave from the product of the plurality of cylinders incorporated in the cylinder block;
The on-off valve control unit sets an independent threshold for the sound pressure level of the noise component extracted by the extraction unit, and any one or more of the noises corresponding to the fundamental wave and the harmonics are set. An accumulator control device that controls the open / close valve to open when each threshold value is exceeded.   The accumulator control device according to any one of claims 1 to 4, wherein the on-off valve is an electromagnetic proportional valve.

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