JP3457595B2 - Valve device - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a valve device having a damping function.

[0002]

2. Description of the Related Art FIG. 6 shows a control circuit of a meter-in / meter-out separation type. In FIG. 6, a control circuit of a bridge structure for controlling a single rod cylinder type fluid pressure actuator 11 is shown.

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

These meter-out valves 23, 24 are connected to the tank line 25, and each meter-out valve
Check valves 26 and 27 for make-up for replenishing hydraulic oil as hydraulic fluid from the tank line 25 to the negative pressure generating portion in the circuit are connected in parallel to the valves 23 and 24.

The passage 31 drawn out between the meter-in valve 21 and the meter-out valve 23 shown above the bridge circuit 18 is a piston of the fluid pressure actuator 11.
A passage 35 connected to a chamber on the side where the rod 33 is located with respect to 32 (hereinafter referred to as “rod-side chamber”) 34, and 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 located on the head side with respect to 32 (hereinafter referred to as “head side chamber”) 36.

An inlet side of the meter-out valve 23 and the meter-out valve 24 is a meter-out passage, that is, a return passage 37 from the fluid pressure actuator 11.

The common bypass valve 14 and the meter-in valve
21 and 22 and meter-out valves 23 and 24 are provided with variable throttle means such as spool valves or poppet valves whose opening areas can be variably controlled by electromagnetic means or pilot hydraulic means, and these variable throttle means are calculated by a controller. An electric signal output from the controller is used to control the pilot pressure signal directly in the case of electromagnetic means and in the case of pilot hydraulic means via an electro-oil conversion means.

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
It is controlled by the bridge circuit 18 formed by the two meter-in valves 21 and 22 and the two meter-out valves 23 and 24.

For example, the fluid pressure actuator 11 is loaded with a load W.
In the case of 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. Side meter-in valve 21 is closed and 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
To close the meter-in valve 22 on the head side and open the meter-out valve 24 on the head side.

FIG. 7A shows a conventional meter-out valve.
Shows the details of the pilot flow rate amplification type poppet valve used as 23 or 24, that is, the flow amplification poppet valve, and the poppet valve 42 is displaceably fitted to the valve fitting hole 41 formed in the valve housing 40. Valve fitting hole
A return passage 37 from the fluid pressure actuator 11 communicates with an inlet chamber 43 formed to have a larger diameter than 41.

A large-diameter pilot control section 44 is formed at one end of the poppet valve 42, and the pilot flow rate control on the outer peripheral surface of the pilot control section 44 is such that the area of the opening 45a changes depending on the position of the poppet valve 42. Slots 45 are formed in the axial direction.

At the opposite end of the poppet valve 42, there is provided a return flow rate control unit 47 which can be brought into and out of contact with a seat 46 formed between an inlet chamber 43 and an outlet chamber 49 communicating with the tank 15. A main flow rate control slot 48 is formed in the return flow rate control unit 47 provided.

The left end surface of the poppet valve 42 shown in FIG. 7A faces the spring chamber 51, and the coil spring 52 built in this spring chamber 51 causes the poppet valve 42 to be pressed toward the seat 46. That is, it is pressed in the closing direction.

As a means for controlling the opening of the poppet valve 42, a passage 53 is arranged from the spring chamber 51 to the outlet chamber 49, and a pilot valve 54 is interposed in this passage 53. This pilot valve 54 has a spring chamber 51
The pilot flow rate discharged from the, by the electrical signal input to the solenoid 55 from the controller (not shown)
It is proportionally controlled against the spring 56.

Next, the operation of the conventional meter-out valve shown in FIG. 7 will be described.

Return flow rate Q from the fluid pressure actuator 11
Is introduced into the inlet chamber 43 of the poppet valve 42, where the flow rate q
Flows into the spring chamber 51 through the opening 45a of the slot 45.

The stroke control of the poppet valve 42 is achieved by controlling the opening of a pilot valve 54 communicating with the spring chamber 51, and the flow rate passing through this pilot valve 54 is shown by q in the figure.

By controlling the stroke of the poppet valve 42, the main flow rate control slot 48 at the right end in the drawing is opened, and the main flow rate LQ is controlled. As for this main flow rate LQ, the pilot flow rate q at the pilot valve 54 is amplified. Show an appearance. That is, the pilot valve 54 has the modulation function of the poppet valve 42.

As described above, the slot 45 is axially machined on the outer periphery of the poppet valve 42, and the pressure P1 of the inlet chamber 43 is increased.
Is transmitted to the spring chamber 51 through the opening 45a of the slot 45, and the pressure P2 of the spring chamber 51 is equal to the pressure P1 of the inlet chamber 43 while the pilot valve 54 is closed.

Therefore, when the pressure P3 of the outlet chamber 49 communicating with the tank line 25 is sufficiently low, the poppet valve 42 has an axial pressure receiving area A2 facing the spring chamber 51 and an axial pressure receiving area A2 facing the inlet chamber 43. Since the axial pressure receiving area A3 facing the outlet chamber 49 is larger than the directional pressure receiving area A1, it is pushed rightward in the drawing and pressed by the sheet 46, and is in the closed state. Less than,
The axial pressure receiving area is simply called "pressure receiving area".

Next, when the pilot valve 54 opens and the pilot flow rate q discharged from the spring chamber 51 reaches a predetermined amount, a pressure reducing action is exerted at the opening 45a of the slot 45, and the pressure in the spring chamber 51 is increased. P2 is (A1 * P1
-Spring force) / A2, poppet valve 42
Moves to the left and makes a stroke, and the opening area of the slot 45 increases, so the flow rate q increases, the pressure P2 in the spring chamber 51 rises slightly, and the poppet valve 42 is pushed back slightly to the right. , Stop at the balance position.

Further, as the opening of the pilot valve 54 increases, the flow rate q increases, the poppet valve 42 moves further leftward, and the opening of the main flow control slot 48 at the tip portion also gradually increases. To go.

[0025]

This conventional poppet valve
Fig. 8 shows 42 when the flow force generated in the main flow control slot 48 and the force imbalance due to the manufacturing position tolerance of the slot 45 are large, or when the damping factor due to the oil film viscous resistance in the sliding portion is small. Spring room
As shown by the simulation result showing the fluctuation of the pressure P2 at 51 and the simulation result showing the fluctuation of the poppet valve displacement X in FIG. 9, there is a defect that hunting H occurs, and the operation becomes unstable.

The present invention has been made in view of the above circumstances, and an object thereof is to prevent the occurrence of hunting which makes the operation of the movable valve element unstable.

[0027]

Means for Solving the Problems The invention described in 請 Motomeko 1 includes a valve housing, slide itself in the valve housing
Movable valve body fitted to the valve, valve housing and movable valve
The internal volume is changed by the displacement of the movable valve body that is provided between the body and
Damping pressure chamber and the inside of the damping pressure chamber
Moves between the inside and outside of the damping pressure chamber as the volume changes.
And a resistance imparting portion that imparts resistance to the fluid, and the movable valve body is a pilot flow rate amplification type poppet valve that controls the main flow rate by the pilot flow rate. An inlet chamber formed on the upstream side, an outlet chamber for the main flow rate discharged through the seat, a spring chamber formed on the opposite side of the outlet chamber via a poppet valve, and a pilot flow rate discharged from the spring chamber Control valve, a spring that is provided in the spring chamber to press the poppet valve toward the seat side, a slot that is provided on the outer peripheral surface of the poppet valve and whose opening area changes to the spring chamber due to movement of the poppet valve, and an inlet A damping pressure chamber is provided between the chamber and the slot, and the damping pressure chamber is connected to the valve housing between the inlet chamber and the slot. Inner diameter of the valve housing where the large diameter part of the poppet valve, a small diameter part slightly smaller in diameter than the large diameter part of the poppet valve, and a small diameter part provided on the inlet chamber side, and the large diameter part of the poppet valve are slidably fitted And an annular protrusion protruding from the inner peripheral surface of the valve housing toward the small diameter portion of the poppet valve, and the resistance applying portion is provided between the small diameter portion of the poppet valve and the annular protrusion. It is a valve device with a gap provided in the.

Then, the damper when the movable valve body moves
Fluid moving with internal volume change in the pressure chamber
By applying resistance to the movable valve body,
Has a damping function to prevent the occurrence of hunting
Secure the operational stability and smoothness of the movable valve body. When the poppet valve moves, the large diameter part of the poppet valve displaces from the annular projection of the valve housing, the volume of the inside of the damping pressure chamber changes between these, and the fluid flows in and out of the damping pressure chamber through the gap. . At that time, a damping function that damps the unstable behavior of the poppet valve works by applying throttling resistance to the flowing fluid in and out to prevent hunting of pressure in the spring chamber and hunting of displacement of the poppet valve. Secure the operation stability and smoothness of the poppet valve.

[0029] The invention described in claim 2, cut in the valve device according to claim 1, and a check valve that allows free flow of fluid to the damping pressure chamber from the inlet chamber, the abnormally high pressure of the damping pressure chamber And a relief valve.

When the gap as the damping pressure chamber and the resistance applying portion functions as a clearance damper, the check valve prevents a hollow state including air in the damping pressure chamber which occurs when the poppet valve suddenly opens. Also, a clearance damper that prevents vibration of the poppet valve by preventing abnormal high pressure in the damping pressure chamber and delay in closing response of the poppet valve when the poppet valve is suddenly closed is prevented by the relief valve for abnormal high pressure cut. Function of
Make it more stable.

The invention described in claim 3 is the valve device according to claim 2, wherein the relief valve is provided inside the check valve.

The check valve and the relief valve are compactly integrated.

[0033]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to FIG.
It will be described with reference to FIGS.

First, an embodiment of the present invention will be described with reference to FIG.

FIG. 1A shows the meter-out valve 23.
Or 24 (FIG. 6), which shows the internal structure of a pilot flow rate amplification type poppet valve for controlling the main flow rate by the pilot flow rate, that is, a flow amplification poppet valve, and a valve fitting hole formed in the valve housing 40.
A poppet valve 42 as a movable valve body is displaceably fitted to the valve 41, and an inlet chamber 43 formed to have a larger diameter than the valve fitting hole 41 has a meter-out passage, that is, the fluid pressure actuator 11
The return passage 37 from (FIG. 6) is in communication.

A large diameter pilot control section 44 is formed at one end of the poppet valve 42, and a pilot flow rate control slot 45 is axially formed on the outer peripheral surface of the pilot control section 44. The area of the opening 45a of the slot 45 changes according to the stroke position of the poppet valve 42.

At the opposite end of the poppet valve 42, there is provided a return flow rate control section 47 which can be moved in and out of contact with and slid from a seat 46 formed in the valve housing 40. A main flow control slot 48 is formed. Due to the seat 46, the inlet chamber 43 formed on the upstream side of the seat 46 and the tank line 25 in the tank 15
And an outlet chamber 49 communicated with each other is defined.

A spring chamber 51 is formed on the opposite side of the outlet chamber 49 via the poppet valve 42, and the left end face of the poppet valve 42 shown in FIG. 1A faces the spring chamber 51. The coil spring 52, which is a spring built in the spring chamber 51, causes the poppet valve 42 to move to the seat 46.
Is pressed in the direction of close contact with, that is, the closing direction.

As a means for controlling the opening of the poppet valve 42, a passage 53 is arranged from the spring chamber 51 to the outlet chamber 49, and a pilot valve 54 is interposed in this passage 53. The pilot valve 54 proportionally controls the pilot flow rate discharged from the spring chamber 51 against the spring 56 by an electric signal input to a solenoid 55 from a controller (not shown).

Further, the valve housing 40 and the poppet valve 42
A damping pressure chamber 61 whose internal volume changes due to the displacement of the poppet valve 42 is provided between and.

The damping pressure chamber 61 has a large diameter portion 62 of the poppet valve 42 fitted to the valve housing 40 between the inlet chamber 43 and the slot 45, and a portion of the large diameter portion 62 closer to the inlet chamber 43. A small diameter portion 63 provided with a slightly small diameter, an inner peripheral surface portion 64 of the valve housing 40 into which the large diameter portion 62 is slidably fitted, and a projection from the inner peripheral surface portion 64 toward the small diameter portion 63 of the poppet valve 42. It is formed so as to be surrounded by the annular projection portion 65 provided.

Further, between the small-diameter portion 63 of the poppet valve 42 and the annular projection 65, resistance to the fluid moving between the inside and the outside of the damping pressure chamber 61 due to the change of the internal volume of the damping pressure chamber 61. An appropriate amount of the gap 66 is provided as a resistance applying portion for applying.

Further, inside the poppet valve 42, there is an inlet chamber.
A passage is provided that connects 43 and the slot 45. That is, the passage in the radial direction of the minimum diameter portion 70 that always faces the inlet chamber 43.
71 is formed, a passage 72 formed in the axial direction is communicated with the central portion of the passage 71, a passage 73 formed in the radial direction is communicated with the passage 72, and an extension of the passage 73 is shown in FIG. (B)
As shown in FIG. 3, a passage 74 formed in the shape of an elongated hole is communicated, and this passage 74 is communicated with the slot 45.

As shown in FIG. 1A, the slot 45 has an arcuate groove shape that becomes shallower from the elongated hole-shaped passage 74 toward the spring chamber 51 side, and as shown in FIG. 1B. With the same width, processed in the axial direction of the poppet valve 42, the poppet valve 42
The opening 45 that opens in the spring chamber 51 by the axial movement of
The area of a changes.

The pressure P1 in the inlet chamber 43 is transmitted to the spring chamber 51 through the passages 71, 72, 73, 74 in the poppet valve 42, the slot 45, and the opening 45a of the slot 45 in this order.
When the pilot valve 54 is closed, the pressure P in the spring chamber 51
2 becomes equal to the pressure P1 in the inlet chamber 43.

Next, the operation of the valve device shown in FIG. 1 will be described.

In the damping mechanism of the poppet type flow control valve, when the poppet valve 42 is stationary, in addition to the donut area pressure receiving area AP1 between the return flow rate control portion 47 of the poppet valve 42 and the small diameter portion 63, damping is performed. Pressure chamber 61
The pressure P1 of the inlet chamber 43 also acts on the pressure receiving area Ad of the donut area inside, and in the end, the pressure P1 in the left direction in the figure acts on the entire pressure receiving area A1 of the poppet valve 42 on the inlet chamber 43 side. .

At this time, since the inlet chamber 43 communicates with the spring chamber 51 through the passages 71, 72, 73, 74 in the poppet valve 42, the slot 45 and the opening 45a thereof, the poppet valve 42
The pressure P1 in the inlet chamber 43 also acts on the pressure receiving area A2 on the side of the spring chamber 51 in the right direction in the figure, and the pressure receiving area A2 is larger than the pressure receiving area A1 by the pressure receiving area A3.
Since the pressure P3 in the outlet chamber 49 is connected to the tank line 25 and is sufficiently low, the poppet valve 42 is pushed rightward in the drawing to be in close contact with the seat 46, and is in a closed state.

Next, when the pilot valve 54 opens in response to the electric signal and the pilot flow rate q flowing out from the spring chamber 51 through the passage 53 reaches a predetermined amount, the pressure reducing action is performed at the opening 45a of the slot 45. , Pressure P in the spring chamber 51
When 2 is less than (A1 * P1−spring force of spring 52) / A2, the poppet valve 42 moves to the left and the opening area of the slot 45 increases, so the flow rate q increases and the spring The pressure P2 in the chamber 51 rises slightly, the poppet valve 42 is pushed back slightly to the right, and stops at the balance position.

Further, as the opening degree of the pilot valve 54 is increased, the flow rate q increases, the poppet valve 42 moves further leftward, and the main flow rate control provided in the return flow rate control section 47 at the tip portion. The opening of slot 48 also gradually increases.

Even if an attempt is made to cause an oscillation phenomenon in the poppet valve 42 in the course of this movement, and an attempt is made to oscillate left and right around a certain equilibrium point, at the same time, the oil flow in and out of the damping pressure chamber 61 whose internal volume changes Since it is attempted to be blocked by the throttling resistance due to the gap 66, a damping action, that is, a damping action works, and the simulation result showing the fluctuation of the pressure P2 in the spring chamber 51 of FIG. 2 and the poppet valve of FIG.
As the simulation result showing the displacement X of 42 shows, even at the location h where hunting has conventionally occurred, there is almost no oscillation phenomenon and it is stable.

In addition, this structure does not require a special damping device such as an existing shock absorber or dashpot, and has an advantage that it is an extremely simple and inexpensive structure.

As described above, in the conventional pilot flow rate amplification type poppet valve shown in FIG. 7, hunting tends to occur as shown in FIGS. 8 and 9, while in FIG. The pilot flow rate amplification type poppet valve provides a high damping factor to the poppet valve 42 due to the clearance of the poppet valve outer peripheral portion, and has a simple and inexpensive clearance damping mechanism (hereinafter, this damping mechanism is referred to as a "clearance damper") to mitigate the oscillation phenomenon. ),
Although the dynamic stability of the conventional pilot flow rate amplification type poppet valve can be improved, the following problems also occur.

That is, when the pilot valve 54 is suddenly opened to a large opening, the pressure P2 of the spring chamber 51 is drastically reduced, and the pressure P1 of the inlet chamber 43 acting on the pressure receiving area Ap1 of the portion directly facing the inlet chamber 43. When the poppet valve 42 suddenly makes a sharp stroke to the left due to the force generated by the force of the gap 66, the resistance of the gap 66 cannot keep up with the replenishment of pressure oil from the inlet chamber 43 to the damping pressure chamber 61, and the damping pressure chamber 61 contains a cavity containing air. And the damping function that suppresses the oscillation phenomenon is lost.

Further, when the poppet valve 42 is in the high lift state and the pilot valve 54 is suddenly closed, the pressure P2 in the spring chamber 51 becomes equal to the pressure P1 in the inlet chamber 43, and the pressure receiving area which is the difference between the pressure receiving area A2 and the pressure receiving area A1. When the pressure P1 of the inlet chamber 43 acts on A3 to push the poppet valve 42 to the right on the closing side, if the damping pressure chamber 61 is filled with hydraulic oil, the pressure receiving area Ad is small, so the damping pressure chamber 61 is small. The pressure Pd becomes abnormally high, which may cause problems such as damage of the valve housing 40 and reduction of the closing response.

Therefore, as shown in the circuit diagram of the embodiment shown in FIG. 4, the damping pressure chamber 61 is inserted from the inlet chamber 43 into the passage 80 which allows the damping pressure chamber 61 and the inlet chamber 43 to communicate with each other.
Is provided with a check valve 81 for allowing free flow of pressure oil to the check valve 81, and an abnormal high pressure relief valve 82 for cutting abnormal high pressure so that the pressure Pd of the damping pressure chamber 61 does not become abnormally high. It is placed in parallel with.

FIG. 5 shows an embodiment in which the circuit diagram shown in FIG. 4 has a specific valve structure. In the valve housing 40 of the pilot flow amplification type poppet valve or in a separate valve housing, an inlet chamber is provided. A valve chamber 83 having a larger diameter than the passage 80a on the 43 side and the passage 80b on the damping pressure chamber 61 side is formed, and a check valve seat 84 is formed on the opening edge of the passage 80a on the inlet chamber 43 side opening to the valve chamber 83. This check valve seat
A poppet-type check valve body 85, which is fitted in the valve chamber 83 so as to be slidable in the axial direction, is provided so as to be able to come in contact with and separate from the valve chamber 84. A spring seat 86 is formed at the opening edge, and a poppet-type check valve body 85 is used as a check valve seat 84 in a check valve spring chamber 87 formed between the spring seat 86 and a facing portion of the poppet-type check valve body 85. A coil-shaped low-load check valve spring 88 for pressing is fitted in a compressed state.

A plurality of axial grooves 89 which allow the free flow of the pressure oil from the inlet chamber 43 to the damping pressure chamber 61 are provided on the outer peripheral sliding surface of the poppet type check valve body 85.

When the damping pressure chamber 61 becomes a hollow state including air, the pressure acting on the poppet type check valve body 85 from the inlet chamber 43 resists the poppet type check valve body 85 against the low load check valve spring 88. Then, the pressure oil that pushed open from the check valve seat 84 and flowed into the valve chamber 83 was released in the axial groove.
The structure is such that it is guided to the damping pressure chamber 61 via 89 and the check valve spring chamber 87 without resistance.

The abnormal high-pressure cutting relief valve 82 which opens due to the abnormal high pressure of the damping pressure chamber 61 and relieves the pressure oil in the damping pressure chamber 61 to the inlet chamber 43 side,
It is built in the check valve 81.

That is, in the relief valve 82 for cutting the abnormal high pressure, the relief valve spring chamber 91 is provided inside the poppet type check valve body 85, and the relief valve spring chamber 91 has a relief valve spring chamber 91 at the end on the damping pressure chamber 61 side. Sheet
A relief valve inlet 93 is formed via 92, and a relief valve outlet 95 is provided on the opposite side via a spring seat 94,
Poppet type relief valve body in the relief valve spring chamber 91
96 is movably fitted in the axial direction, and the spring fitting portion 97 of the poppet type relief valve body 96 and the spring seat
The poppet-type relief valve body 96 is pressed against the relief valve seat 92 by a coil-shaped relief valve spring 98 that is fitted in a compressed state with the relief valve seat 94.

When the pressure Pd in the damping pressure chamber 61 rises abnormally and the force based on the pressure Pd exceeds the force set by the relief valve spring 98, the pressure oil in the damping pressure chamber 61 becomes poppet. The mold relief valve body 96 is pushed open from the relief valve seat 92 against the relief valve spring 98, and flows out of the relief valve inlet 93, the relief valve spring chamber 91, and the relief valve outlet 95.

The operation and effect of the embodiment shown in FIG. 4 will be described.

When the pilot valve 54 is suddenly opened to a large opening, the pressure P2 in the spring chamber 51 is drastically decreased, and the poppet valve 42 is rapidly ablated by the force generated by the pressure P1 in the inlet chamber 43 acting on the pressure receiving area Ap1. When making a sudden leftward stroke, the resistance from the gap 66 causes the damping pressure chamber to move from the inlet chamber 43.
The pressure oil cannot be replenished to the 61, and the damping pressure chamber 61 becomes a hollow state including air.However, in this device, the space between the inlet pressure chamber 61 and the inlet pressure chamber 43 is changed to the damping pressure chamber 61. Since the check valve 81 that allows the free flow of the pressure oil is provided, the hollow state including air in the damping pressure chamber 61 is quickly eliminated, and the damping pressure chamber 61 is filled with the hydraulic oil. When the poppet valve 42 moves from the center position of the vibration to the right in the figure, the hydraulic oil filled in the damping pressure chamber 61 exerts a damping function of suppressing the vibration by the resistance pushed out from the gap 66, so that the vibration is quickly generated. Decay. Further, since the relief valve 82 that cuts the high pressure so that the pressure Pd of the damping pressure chamber 61 does not become abnormally high is installed in the direction from the damping pressure chamber 61 to the inlet chamber 43, the valve housing 40 is damaged and the closing response is deteriorated. Such problems do not occur.

The operation and effect of the specific valve structure shown in FIG. 5 will be described.

Between the damping pressure chamber 61 and the inlet chamber 43, there is provided a poppet type check valve which allows the free flow of the pressure oil from the inlet chamber 43 to the damping pressure 61, and the outer peripheral portion of this poppet type check valve. Is provided with an axial groove that communicates in the axial direction, and the pressure oil that pushes in the check valve seat from the inlet chamber 43 and flows in is supplied from the axial groove on the outer periphery of the check valve and the damping pressure chamber 61 from the check valve spring chamber 87. Therefore, the damping pressure chamber 61 can be promptly released from a hollow state including air because it can be guided smoothly without resistance. Further, since the check valve 81 has a built-in relief valve 82 for abnormally high pressure cut that opens due to the abnormally high pressure of the damping pressure chamber 61 and relieves the pressure oil in the damping pressure chamber 61 to the inlet chamber 43 side, The entire structure can be made compact, and problems such as damage to the housing and lowering of the closing response do not occur.

As described above, when the damping pressure chamber 61 and the gap 66 for improving the dynamic stability of the conventional pilot flow rate amplification type poppet valve function as a clearance damper, the poppet valve 42 suddenly opens (lifts). The check valve 81 prevents a hollow state including air in the damping pressure chamber 61 that occurs when the damping pressure chamber 61 is constantly filled, and the damping pressure chamber 61 is constantly filled with pressure oil to stably maintain the damping function of suppressing oscillation. At the same time, since an abnormally high pressure relief valve 82 for preventing an abnormally high pressure in the damping pressure chamber 61 and a closing response delay of the poppet valve 42 that occur when the poppet valve 42 is suddenly closed is installed, It is possible to provide a mechanism in which the function of the clearance damper that prevents vibration is more stably maintained and has high reliability.

Further, since the relief valve 82 is provided inside the check valve 81, the check valve 81 and the relief valve 82 can be compactly integrated, and these can be compactly assembled in the valve housing 40 of the poppet valve 42 or the like. You can

Although the illustrated embodiment has explained the damping mechanism in the poppet type flow control valve, the damping pressure chamber and the resistance applying portion are provided between the spool valve as the movable valve body and the valve housing. Therefore, the same damping mechanism can be applied to the spool type control valve.

Further, in this case, the present invention is applied to the poppet valve used for the flow control on the meter-out side, but the present damping mechanism can be applied to the poppet valve for the flow control on the meter-in side as well.

[0071]

Effects of the Invention] According to the invention 請 Motomeko 1, wherein the movable valve body
To the internal volume change in the damping pressure chamber when the
With the fluid that moves between the inside and outside of the damping pressure chamber,
The resistance is applied to the movable valve body by applying resistance to it.
Allowing to prevent hunting by providing a pumping function
The operational stability and smoothness of the valve operating body can be secured. Also,
Damping pressure chamber between valve housing and movable valve body
And by providing a resistance applying part, existing shock
From a damping device such as an absorber or dashpot,
A pull and inexpensive structure can be made. In addition, seats, entrance rooms,
Even when controlling the flow rate with a pilot flow rate amplification type poppet valve equipped with an outlet chamber, a spring chamber, a pilot valve, a spring and a slot, when this poppet valve moves, the large diameter part of the poppet valve moves into an annular shape on the valve housing side. Displacement from the protrusion changes the internal volume of the damping pressure chamber between them, and imparts throttling resistance to the fluid entering and exiting the damping pressure chamber through the gap, thereby damping the movement of the poppet valve. Therefore, hunting of pressure in the spring chamber and hunting of displacement of the poppet valve can be prevented, and the operational stability and smoothness of the poppet valve can be secured. In particular, the inlet chamber and the slot are communicated with each other through a passage, and the small diameter portion slightly smaller in diameter than the large diameter portion of the poppet valve and the annular protrusion protruding from the valve housing side are used for damping. The pressure chambers and gaps can be easily formed, and the structure can be made extremely simple and inexpensive compared to existing damping devices such as shock absorbers and dashpots.

According to the second aspect of the present invention, when the damping pressure chamber and the gap serving as the resistance applying portion function as a clearance damper, a hollow state including air in the damping pressure chamber that occurs when the poppet valve suddenly opens. Can be prevented by a check valve, and the abnormal high pressure in the damping pressure chamber and delay in closing response of the poppet valve that occur when the poppet valve is suddenly closed can be prevented by the relief valve for abnormal high pressure cut. The function of the clearance damper that prevents the occurrence of vibration can be more stably maintained.

According to the third aspect of the invention, since the relief valve is provided inside the check valve, the check valve and the relief valve can be compactly integrated, and these can be made compact in the valve housing of the poppet valve or the like. Can be incorporated.

[Brief description of drawings]

1A is a sectional view showing an embodiment of a valve device according to the present invention, and FIG. 1B is a plan view of a part of a movable valve body thereof.

FIG. 2 is a characteristic diagram showing a simulation result of pressure fluctuation of a spring chamber in the same valve device.

FIG. 3 is a characteristic diagram showing a displacement simulation result of a poppet valve in the above valve device.

FIG. 4A is a cross-sectional view showing another embodiment of the valve device according to the present invention, and FIG. 4B is a plan view of a part of the movable valve body.

5 is a cross-sectional view embodying a check valve and a relief valve for improving the clearance damper function in the valve device shown in FIG.

FIG. 6 is a circuit diagram showing a meter-in / meter-out separated type control circuit.

7A is a sectional view showing a conventional poppet type flow control valve, and FIG. 7B is a plan view of a part of the poppet valve.

FIG. 8 is a characteristic diagram showing a pressure fluctuation simulation result of a spring chamber in the same flow control valve.

FIG. 9 is a characteristic diagram showing displacement simulation results of the poppet valve in the above flow control valve.

[Explanation of symbols] 40 Valve housing 42 Poppet valve as movable valve body 43 Inlet chamber 45 Slot 46 Seat 49 Outlet chamber 51 Spring chamber 52 Coil spring as spring 54 Pilot valve 61 Damping pressure chamber 62 Large diameter portion 63 Small diameter portion 64 Inner peripheral surface 65 Annular protrusion 66 Gap 71, 72, 73, 74 as resistance applying part Passage 81 Check valve 82 Relief valve

─────────────────────────────────────────────────── ─── Continuation of the front page (58) Fields surveyed (Int.Cl. ⁷ , DB name) F16K 17/00-17/34 F16K 47/02 F15B 11/02

Claims (3)

(57) [Claims] 1. A valve housing, a movable valve body slidably fitted in the valve housing, and a movable valve body provided between the valve housing and the movable valve body.
Of the damping pressure chamber whose internal volume changes due to the displacement of the
Apply resistance to fluid moving between the inside and outside of the pressure chamber
The movable valve element is a pilot flow rate amplification type poppet valve that controls the main flow rate by the pilot flow rate, and the seat to which the poppet valve is connected and separated and the inlet chamber formed on the upstream side of the seat are provided. The outlet chamber for the main flow rate discharged through the seat, the spring chamber formed on the opposite side of the outlet chamber via the poppet valve, the pilot valve for controlling the pilot flow rate discharged from the spring chamber, and the spring A spring that is provided in the chamber to press the poppet valve toward the seat side, a slot that is provided on the outer peripheral surface of the poppet valve and whose opening area to the spring chamber changes due to the movement of the poppet valve, and a passage that connects the inlet chamber and the slot The damping pressure chamber includes a large diameter portion of the poppet valve fitted with the valve housing between the inlet chamber and the slot, and a poppet valve. From the inner diameter of the valve housing to the inner diameter of the valve housing, where the small diameter of the valve is slightly smaller than the diameter of the valve, and the large diameter of the poppet is slidably fitted. It is formed by an annular protrusion protruding toward the small diameter portion of the poppet valve, and the resistance applying portion is a gap provided between the small diameter portion of the poppet valve and the annular protrusion. It is that the valve device. Wherein the inlet chamber and the check valve that allows free flow of fluid to the damping pressure chamber, according to claim 1, characterized by including a relief valve to cut abnormally high damping pressure chamber Valve device. 3. The valve device according to claim 2 , wherein the relief valve is provided inside the check valve.