JP2001141108A - Valve appliance - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve the stability, and the vibration and noises of the whole system by preventing the pressure pulsation caused by the chattering of a back- pressure control valve provided on a discharge passage side of a poppet valve from being applied to a pilot system to mitigate the pulsation in the flow rate of the poppet valve. SOLUTION: The make-up function when the negative pressure is generated in a circuit is promoted by increasing the back pressure of the main flow rate discharged into a discharge passage 25 via the poppet valve 42 of the pilot flow rate amplification type to control the main flow rate by the pilot flow rate using a back pressure check valve 59. A pilot stage valve 64 to displace the poppet valve 42 by controlling the pilot flow rate is communicated with the discharge passage 25 via a pilot passage 63. An expansion type hydraulic muffler 71 to filter and damp the pressure pulsation caused by the chattering of the back pressure check valve 59 propagating in the direction opposite to the direction of the pilot flow rate from the pilot stage valve 64 is inserted in this pilot passage 63.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a poppet valve type valve device.

[0002]

2. Description of the Related Art FIG. 3 shows a control circuit of a meter-in / meter-out type, and FIG. 3 shows a control circuit of a bridge configuration for controlling a single rod / cylinder type fluid pressure actuator 11.

In this control circuit, a tank 15 is connected via a common bypass valve 14 to a discharge port of a variable displacement pump 13 capable of variably controlling a discharge flow rate by a swash plate 12, and a load hold check valve 16 is connected. Having pump line
A bridge circuit 18 is connected via 17.

The bridge circuit 18 includes two meter-in valves 21 and 22 connected to the pump line 17, respectively.
It is formed by two meter-out valves 23 and 24 connected to these meter-in valves 21 and 22, respectively.

[0005] These meter-out valves 23, 24 are connected to a discharge passage 25.
The check valve 24 is provided with a make-up check valve for replenishing the working fluid as a working fluid from the discharge passage 25 to the negative pressure generating section in the circuit (hereinafter, this check valve is referred to as a “make-up valve”).
26 and 27 are connected in parallel.

[0006] A passage 31 drawn out between the meter-in valve 21 and the meter-out valve 23 illustrated above the bridge circuit 18 is provided with a piston of the fluid pressure actuator 11.
A passage 35 is connected to a chamber 34 (hereinafter, referred to as a “rod side chamber”) on the side where the rod 33 is located relative to 32, and is drawn out from between the meter-in valve 22 and the meter-out valve 24 shown below. Is the piston of the fluid pressure actuator 11
It is connected to a chamber (hereinafter, referred to as “head-side chamber”) 36 located on the head side of 32.

The inlet sides of the meter-out valve 23 and the meter-out valve 24 form a meter-out passage, that is, a return passage 37 from the fluid pressure actuator 11 (hereinafter, this passage is referred to as an “actuator passage”) 37.

[0008] The common bypass valve 14, meter-in valve
The throttle valves 21 and 22 and the meter-out valves 23 and 24 are provided with variable throttle means such as a spool valve or a poppet valve whose opening area can be variably controlled by electromagnetic means or pilot hydraulic means. These variable throttle means are operated by a controller. In the case of electromagnetic means, control is directly performed by an electric signal output from the controller, and in the case of pilot hydraulic means, control is performed by a pilot pressure signal via electro-hydraulic conversion means.

Then, the hydraulic oil supplied from the pump 13 to one of the rod side chamber 34 and the head side chamber 36 of the fluid pressure actuator 11 and discharged from the other to the tank 15 is
The control is performed by a bridge circuit 18 formed by the two meter-in valves 21 and 22 and the two meter-out valves 23 and 24.

For example, when the fluid pressure actuator 11 is
When performing the extension operation against the pressure, the common bypass valve 14 is closed, the discharge amount of the pump 13 is increased, the meter-in valve 22 on the head side of the fluid pressure actuator 11 is opened, and the meter-out valve 24 is closed. The meter-in valve 21 on the side is closed and the meter-out valve 23 is opened.

When the fluid pressure actuator 11 is contracted, the common bypass valve 14 is closed, the discharge amount of the pump 13 is increased, the meter-in valve 21 on the rod side of the fluid pressure actuator 11 is opened, and the meter-out valve is opened. twenty three
Is closed, the meter-in valve 22 on the head side is closed, and the meter-out valve 24 on the head side is opened.

FIG. 4A shows a conventional meter-out valve.
The details of the pilot flow amplification type poppet valve device used as 23 or 24, that is, the flow amplification poppet valve device, are shown, and a poppet valve 42 is displaceably fitted into a valve fitting hole 41 formed in a valve housing 40. And
The actuator passage 37 is communicated with an inlet chamber 43 having a larger diameter than the valve fitting hole 41.

A large-diameter pilot control unit 44 is formed at the left end of the poppet valve 42. A pilot flow control slot 45 is formed in the outer peripheral surface of the pilot control unit 44 in the axial direction. The slot 45 has a constant width W as shown in FIG.

A part of the slot 45 is open to a spring chamber 61 described later even when the poppet valve 42 is fully closed, and the area of the opening 46 varies depending on the position of the poppet valve 42.

The poppet valve 42 has a small-diameter portion 51 facing the inlet chamber 43 with respect to the large-diameter pilot control portion 44 fitted in the valve fitting hole 41 of the valve housing 40.

Further, the poppet valve 42 is provided with a passage communicating the inlet chamber 43 and the slot 45. That is, the passage 52 is formed in the radial direction of the small-diameter portion 51 which always faces the inlet chamber 43, and the passage formed in the center of the passage 52 in the axial direction.
53 communicates with this passage 53, and a passage formed in the radial direction.
As shown in FIG. 4B, a passage 55 formed in a long hole shape is communicated with an extension of the passage 54, and the passage 55 communicates with the slot 45.

At the right end of the poppet valve 42, an inlet chamber 43 is provided.
A return flow control unit 57 is provided, which is slidable and slidable with respect to a sheet 56 formed between the discharge flow passage 25 and the discharge passage 25 connected to the tank 15. A notch 58 is formed.

In the discharge passage 25 connecting the discharge side of the sheet 56 and the tank 15, a back pressure check valve 59 for increasing the back pressure of the main flow discharged through the sheet 56 to promote a make-up function is provided. is set up. The back pressure is set by a spring 60.

The left end face of the poppet valve 42 shown in FIG. 4A faces a spring chamber 61, and a compression coil-shaped spring 62 built in the spring chamber 61 causes the poppet valve to be closed.
42 is pressed in the direction pressed toward the sheet 56, that is, in the closing direction.

As means for controlling the degree of opening of the poppet valve 42, a pilot passage 63 is provided from the spring chamber 61 to the discharge passage 25 located upstream of the back pressure check valve 59. A stage valve 64 is interposed. The pilot stage valve 64 proportionally controls the pilot flow discharged from the spring chamber 61 against the spring 66 by an electric signal input from a controller (not shown) to the solenoid 65.

Next, the operation of the conventional meter-out valve shown in FIG. 4 will be described.

Return flow Q from the fluid pressure actuator 11
Is led to the inlet chamber 43 of the poppet valve 42 and the flow rate q therein
Flows into the spring chamber 61 through the opening 46 of the slot 45.

The stroke control of the poppet valve 42 is achieved by controlling the opening of a pilot stage valve 64 connected to the spring chamber 61. The pilot flow rate passing through the pilot stage valve 64 is indicated by q in the figure.

By controlling the stroke of the poppet valve 42, a notch 58 for controlling the main flow at the right end in the figure is opened, and the main flow LQ is controlled. q
Indicates an amplified state. That is, the pilot stage valve 64 has a modulation function of the poppet valve 42.

To explain this, a slot 45 is formed in the outer periphery of the poppet valve 42 in the axial direction, and the pressure P1 of the inlet chamber 43 is transmitted to the spring chamber 61 from the opening 46 of the slot 45, and the pilot stage valve 64 Is closed, the pressure P2 in the spring chamber 61 is equal to the pressure P1 in the inlet chamber.

Therefore, when the pressure P3 in the discharge passage 25 upstream of the back pressure check valve 59 is sufficiently low, (P3
Is almost zero), the poppet valve 42 is
The pressure receiving area A2 on the side is larger than the donut area pressure receiving area A1 on the inlet chamber 43 side.
It is pressed by 56 and is in the closed state.

Next, when the pilot stage valve 64 is gradually opened and the pilot flow rate q discharged from the spring chamber 61 reaches a predetermined amount, a pressure reducing action works at the opening 46 of the slot 45, and the spring chamber 61 is opened. Pressure P2 is (A1
When the value falls below the value of (P1-spring force of the spring 62) / A2, the poppet valve 42 moves to the left and has a constant width W.
The opening 46 of the slot 45 is gradually expanded from the initial opening length Xo to increase the opening area, so that the flow rate q increases, the pressure P2 of the spring chamber 61 slightly increases, and the poppet valve 42 is slightly pushed back to the right and then stops at the balance position.

Further, as the opening area Ap of the pilot stage valve 64 increases, the pilot flow rate q increases, the poppet valve 42 moves further to the left (stroke X), and the opening at the tip of the poppet valve 42 opens. The area, that is, the opening area AL (X) of the main flow rate control notch 58 gradually increases from zero, and the main flow rate LQ joins the pilot flow rate q.

Here, the poppet valve 42 controls the return flow rate Q from the actuator passage 37, but due to the voiding generated in the actuator 11 by the fluid pressure actuator 11, a pressure lower than the atmospheric pressure (hereinafter, referred to as the pressure).
When this pressure is referred to as "negative pressure", if the pilot stage valve 64 is in the neutral block position, the pilot flow rate q becomes zero, and the pressure P2 of the spring chamber 61 of the poppet valve 42 becomes the pressure of the inlet chamber 43. Since the pressure P1 is equal to P1, the pressure P3 in the discharge passage 25 when the return oil from another system passes through the back pressure check valve 59 is higher than the negative pressures P1 and P2. Reference numeral 42 floats to the left in the drawing, and hydraulic oil flows into the actuator passage 37 from the discharge passage 25, so that a make-up function for preventing voiding of the fluid pressure actuator 11 is achieved.

Further, while the actuator passage 37 controls the pilot stage valve 64 at a high pressure, a pilot flow q is generated, the poppet valve 42 is lifted to the left, and the tip notch 58 of the poppet valve 42 is raised. Is opened, and the large flow rate LQ is modulated and controlled by the existing pilot flow rate amplification type poppet valve technology.

[0031]

As described above, in a general hydraulic control valve circuit, make-up valves 26 and 27 are installed in order to prevent voiding of the fluid pressure actuator 11, and a discharge connected to the tank 15 is provided. On the side, the pressure P3 of the discharge passage 25, which is the back pressure of the main flow rate, to promote the makeup function
In many cases, a back pressure check valve 59 is installed to increase the pressure.

However, the back pressure check valve 59 sometimes causes chattering. In a configuration in which the pilot flow amplification type poppet valve 42 is used as the hydraulic control valve, the pulsating pressure of the chattering is applied to the poppet valve 42 through the pilot stage valve 64. Is transmitted to the spring chamber 61, and the displacement of the poppet valve 42 oscillates. Cheap.

For this reason, there is a problem that the whole system generates large vibration and noise, and the controllability is extremely deteriorated.

The present invention has been made in view of such a point, and by preventing a pressure pulsation due to chattering of a back pressure control valve provided on a discharge passage side of a poppet valve from acting on a pilot system, An object of the present invention is to reduce the flow pulsation of the poppet valve and improve the stability, vibration and noise of the entire system.

[0035]

According to the first aspect of the present invention, a pilot flow amplification type poppet valve for controlling a main flow by a pilot flow and a back pressure of a main flow discharged through the poppet valve are increased. A back pressure control valve, a pilot stage valve that controls the pilot flow to displace the poppet valve, and a pressure pulsation due to chattering of the back pressure control valve that propagates in a direction opposite to the pilot flow discharged from the pilot stage valve are filtered. And a pulsating filter means for attenuating the pulsation.

The pressure pulsation that reverses the pilot flow can be attenuated by the pulsation filtering means.
Via the pilot stage valve, the pressure amplitude acting on the poppet valve is reduced, so that the vibration level around the equilibrium point of the displacement of the poppet valve can be damped,
The flow pulsation level of the main flow passing through the poppet valve is also improved and the stability and vibration and noise of the entire system are improved.

According to a second aspect of the present invention, there is provided a pilot flow rate amplification type poppet valve for controlling a main flow rate by a pilot flow rate, a sheet to which the poppet valve is brought in and out, and a main flow rate formed upstream of the sheet. An inlet chamber, a discharge passage for discharging the main flow through the sheet to the tank, a back pressure check valve provided in the discharge passage to increase the back pressure of the main flow discharged through the sheet, and a poppet valve opposite to the sheet. And a spring provided in the spring chamber for pressing the poppet valve toward the seat, and controlling a pilot flow discharged from the spring chamber to a discharge passage located upstream of the back pressure check valve. A pilot stage valve and a pipe for guiding the pilot flow discharged from the pilot stage valve to a discharge passage located upstream of the back pressure check valve. And a pulsation filtering means provided in the pilot passage and provided in the pilot passage, for filtering and attenuating pressure pulsations generated by chattering of the back pressure check valve and propagating in a direction opposite to the direction in which the pilot flow rate flows. It is.

The pulsation filtering means provided in the pilot passage connecting the discharge passage of the pilot flow amplification type poppet valve and the pilot stage valve propagates upstream in the direction opposite to the direction in which the pilot flow flows. To filter out the pressure pulsation caused by the back pressure check valve chattering and construct a new combination to attenuate the amplitude of the pressure pulsation and improve the stability, vibration and noise of the whole system.

According to a third aspect of the present invention, the pulsation filtering means according to the first or second aspect is an expansion type hydraulic muffler.

An expansion hydraulic muffler is inserted in a pilot passage connecting the discharge passage of the pilot flow amplification type poppet valve and the pilot stage valve, and the discharge passage propagates upstream in the direction opposite to the flow direction of the pilot flow. Is filtered by an inexpensive inflatable hydraulic muffler to attenuate the amplitude of the pressure pulsation.

According to a fourth aspect of the present invention, the pulsation filtering means according to the first or second aspect is a pulsation phase compensation type side branch.

A pulsation phase compensation type side branch is inserted in a pilot passage connecting the discharge passage of the pilot flow amplification type poppet valve and the pilot stage valve, and propagates upstream in a direction opposite to the flow direction of the pilot flow. The pressure pulsation in the discharge passage is filtered by an inexpensive pulsation phase compensation type side branch to attenuate the amplitude of the pressure pulsation.

[0043]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below with reference to respective embodiments shown in FIGS. In each of the embodiments shown in FIGS. 1 and 2, the same parts as those in the conventional example shown in FIG. 4 are denoted by the same reference numerals, and the description thereof may be omitted.

FIG. 1 shows an embodiment, in which a pilot flow amplification type poppet valve 42 for controlling a main flow LQ by a pilot flow q is provided so as to be able to freely move toward and away from a seat 56, and the upstream of the seat 56. A main flow rate inlet chamber 43 is formed on the side.

Further, on the downstream side of the sheet 56, there is provided a discharge passage 25 for discharging the main flow through the sheet 56 to the tank 15. In the discharge passage 25, a back pressure check valve 59 as a back pressure control valve for increasing the back pressure of the main flow discharged through the sheet 56 is provided. The back pressure of the discharge passage 25 is set by a spring 62.

Further, a spring chamber 61 is formed on the opposite side of the poppet valve 42 with respect to the seat 56, and this spring chamber 61 is formed.
Inside, a spring that presses the poppet valve 42 toward the seat 56
A pilot stage valve 64 for controlling the pilot flow rate q flowing out of the spring chamber 61 to displace the poppet valve 42 is connected to the spring chamber 61.

The pilot stage valve 64 is communicated with the discharge passage 25 located on the upstream side of the back pressure check valve 59 by the pilot passage 63, and is provided upstream of the back pressure check valve 59 from the spring chamber 61 via the pilot stage valve 64. The pilot flow rate q flowing into the discharge passage 25 located on the side is controlled.

In the pilot passage 63, the pressure pulsation generated by the chattering of the back pressure check valve 59, which propagates in the direction opposite to the direction in which the pilot flow rate q discharged from the pilot stage valve 64 flows, is filtered. An expansion hydraulic muffler 71 is provided as pulsation filtering means for attenuating the amplitude of the pressure.

This inflatable hydraulic muffler 71 is an inexpensive simple structure having an inlet 73 on one side of an expansion chamber 72 of length l and an outlet 74 on the other side. Entrance 73
Of the expansion chamber 72 with respect to the cross-sectional area S1 of the
Is formed sufficiently large to cause the traveling wave and the reflected wave to interfere with each other inside the expansion chamber 72, thereby attenuating the pressure pulsation.

As described above, the inexpensive inflatable hydraulic muffler is provided in the pilot passage 63 that connects the discharge passage 25 of the pilot flow amplification type poppet valve 42 and the pilot stage valve 64.
By inserting 71, the amplitude of the pulsation is attenuated by filtering the pressure pulsation in the discharge passage 25 that propagates upstream in the direction opposite to the direction in which the pilot flow rate q flows.

The operation and effect of the embodiment shown in FIG. 1 will be described. An expansion hydraulic muffler 71 is inserted into a pilot passage 63 connecting the pilot stage valve 64 with the discharge passage 25 of the pilot flow amplification type poppet valve 42. , A pressure pulsation in the discharge passage 25 propagating upstream in the direction opposite to the direction in which the pilot flow rate q flows is filtered, and a new combination for attenuating the amplitude of the pressure pulsation is constructed. Improve noise.

The amount of attenuation TL of the pulse pressure is theoretically expressed by the following equation (Shigeru Goto: Report of the University of Tokyo: 10.2 (1960)). S1, S2, S3, l (L) in this equation
Is as shown in FIG.

TL = 10Log ₁₀ 1/4 {(1 + m / m ′) ² cos ² kl +
(m + 1 / m ') ² sin ² kl} +10 Log ₁₀ (m' / m) where m = S2 / S1, m '= S2 / S3, k = 2πf /
C, (where f: frequency, C: sound velocity) Normally, S1 = S3 in many cases, and m = m '. Therefore, from the above equation, although the chattering frequency dependence is present, the effect becomes larger as the m value becomes larger You can read that there is.

Since the pressure pulsation which reverses the pilot flow can be attenuated by the inflatable hydraulic muffler 71, the poppet valve 42 passes through the pilot stage valve 64.
The pressure amplitude acting on the spring chamber 61 becomes smaller, the vibration level of the displacement of the poppet valve 42 around the equilibrium point is attenuated, and the flow rate pulsation level passing through the notch 58 at the tip of the poppet valve 42 can be improved. Stability, vibration and noise of the whole system can be improved.

Next, FIG. 2 shows another embodiment, and FIG.
As in the embodiment shown in FIG. 7, a pilot flow rate amplification type poppet valve 42 for controlling the main flow rate LQ by the pilot flow rate q, and back pressure control for increasing the back pressure of the main flow rate LQ discharged through the poppet valve 42 The valve device includes a back pressure check valve 59 as a valve, and a pilot stage valve 64 that controls the pilot flow rate q to displace the poppet valve 42.
The pressure pulsation in the discharge passage 25 due to the chattering of the back pressure check valve 59 that propagates upstream in the direction opposite to the direction in which the pilot flow rate q discharged from the pilot stage valve 64 flows is filtered to attenuate the amplitude of the pressure pulsation. This is an example in which a pulsation phase compensation type side branch 81 is provided as pulsation filtering means.

The pulsation phase compensation type side branch 81
It is an inexpensive simple structure in which a side branch pipe 84 of length L is provided at a right angle between the inlet passage 82 and the outlet passage 83, and the side branch pipe 84 reflects traveling waves and the pipe from the closed end face. Pressure pulsations are attenuated by interfering with waves.

In the embodiment shown in FIG. 2, the pulsation filtering means inserted into the pilot passage 63 connecting the discharge passage 25 of the pilot flow rate amplification type poppet valve 42 and the pilot stage valve 64 has a pulsation phase compensation type side valve. Except for the branch 81, the configuration is the same as that of the embodiment shown in FIG. 1. Therefore, the same parts as those of the embodiment of FIG.

The operation and effect of the embodiment shown in FIG. 2 will be described. In the pilot passage 63 extending from the discharge passage 25 between the poppet valve 42 and the back pressure check valve 59 to the pilot stage valve 64, Pulsation phase compensation type side branch 81
To filter the pressure pulsation in the discharge passage 25 that propagates upstream in the direction opposite to the direction in which the pilot flow rate q flows, thereby attenuating the amplitude of the pulsation.

The length L of the side branch pipe 84, one end of which is closed by the pulsating phase compensation type side branch 81, is usually a quarter wavelength (= C / 4f) in order to attenuate the pulse pressure. It can be easily calculated from the chattering frequency f and the sound speed C in the oil.

As a result, similarly to FIG. 1, the flow pulsation level at the tip notch 58 of the poppet valve 42 can be reduced and improved.
Stability, vibration and noise of the whole system can be improved.

[0061]

According to the first aspect of the present invention, since the pressure pulsation propagating in the direction opposite to the pilot flow can be attenuated by the pulsation filtering means, the pressure acting on the poppet valve via the pilot stage valve can be reduced. The amplitude can be reduced, the vibration level around the equilibrium point of the displacement of the poppet valve can be attenuated, the pulsation level of the main flow passing through the poppet valve can also be improved, and the stability, vibration and noise of the whole system can be reduced. Can be improved.

According to the second aspect of the present invention, the flow direction of the pilot flow is determined by the pulsation filtering means provided in the pilot passage connecting the discharge passage of the pilot flow amplification type poppet valve and the pilot stage valve. By filtering the pressure pulsation caused by the back pressure check valve chattering propagating upstream in the opposite direction, a new combination for attenuating the amplitude of the pressure pulsation can be constructed, and the stability, vibration and noise of the whole system can be improved.

According to the third aspect of the present invention, by inserting an inexpensive inflatable hydraulic muffler into the pilot passage connecting the pilot stage valve from the discharge passage of the pilot flow amplification type poppet valve, The pressure pulsation of the discharge passage propagating to the upstream side in the opposite direction can be filtered by an inexpensive inflatable hydraulic muffler to attenuate the amplitude of the pulsation.

According to the fourth aspect of the present invention, an inexpensive pulsating phase compensation type side branch is inserted into the pilot passage connecting the pilot stage valve from the discharge passage of the pilot flow amplification type poppet valve, and the direction in which the pilot flow flows. The pressure pulsation of the discharge passage propagating upstream in the opposite direction is filtered by the inexpensive pulsation phase compensation type side branch to attenuate the pulsation amplitude.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view showing one embodiment of a valve device according to the present invention.

FIG. 2 is a cross-sectional view showing another embodiment of the valve device according to the present invention.

FIG. 3 is a circuit diagram showing a meter-in / meter-out separated control circuit.

FIG. 4 is a sectional view showing a conventional valve device.

[Explanation of symbols]

15 Tank 25 Discharge passage 42 Poppet valve 43 Inlet chamber 56 Seat 59 Back pressure check valve as back pressure control valve 61 Spring chamber 62 Spring 63 Pilot passage 64 Pilot stage valve 71 Inflatable hydraulic muffler as pulsation filtering means 81 Pulsating filtering means Phase compensation type side branch

Continued on the front page F term (reference) 3H056 AA01 BB11 BB46 BB49 CA02 CB02 CB07 CB09 CD02 CD06 DD02 EE01 GG04 GG12 3H059 AA02 BB12 BB15 BB28 BB37 BB38 CA03 CA04 CA12 CC02 CD05 CE05 CF02 DD01 EE13 A33 BA03 AA60 BB10 BB26 CC01 DA03 DB02 DB73 DB80 EE01 EE06 EE13 GG01

Claims (4)

[Claims] 1. A pilot flow amplification type poppet valve for controlling a main flow by a pilot flow, a back pressure control valve for increasing a back pressure of a main flow discharged through the poppet valve, and a poppet valve for controlling a pilot flow And a pulsation filtering means for filtering and attenuating pressure pulsation due to chattering of the back pressure control valve which propagates in a direction opposite to the pilot flow discharged from the pilot stage valve. Valve device to do. 2. A pilot flow amplification type poppet valve for controlling a main flow rate by a pilot flow rate, a seat to which the poppet valve is connected / disconnected, an inlet chamber for a main flow rate formed upstream of the seat, and a main flow passing through the seat. A discharge passage for discharging the flow rate to the tank, a back pressure check valve provided in the discharge path to increase the back pressure of the main flow discharged through the seat, and a spring chamber formed on the opposite side of the poppet valve with respect to the seat. A spring provided in the spring chamber to press the poppet valve to the seat side; a pilot stage valve for controlling a pilot flow rate discharged from the spring chamber to a discharge passage located upstream of the back pressure check valve; and a pilot stage valve. A pilot passage for guiding the pilot flow discharged from the pilot passage to a discharge passage located upstream of the back pressure check valve; And a pulsation filter means provided in the passage for filtering and attenuating pressure pulsations generated by chattering of the back pressure check valve and propagating in a direction opposite to the flow direction of the pilot flow rate. . 3. The valve device according to claim 1, wherein the pulsation filtering means is an inflatable hydraulic muffler. 4. The valve device according to claim 1, wherein the pulsation filtering means is a pulsation phase compensation type side branch.