JPH11173436A - Poppet flow control valve - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide constant flow control characteristics without a special adjustment in a poppet flow control valve even when the seating position of a poppet is changed by a cause that the seat surface part and valve seat part of the poppet are worn, deformed and so on. SOLUTION: A flow controlling notch 32 by which an input port 21 is communicated with a back pressure chamber 26 is formed in a poppet 28, and the pressure of the back pressure chamber 26 is lowered by the operation of a pilot operated variable restriction 51 connected to the back pressure chamber 26 so as to operate the poppet 28, thereby flow control is carried out. A passing hole 30 having a fixed restriction 31, by which the input port 21 is communicated with the back pressure chamber 26 is arranged in the poppet 28 separately from the flow controlling notch 32, and the notch 32 is so formed that it disconnects the communication between the input port 21 and the back pressure chamber 26 in the closing position of the poppet 28. Distance to the opening start point of the notch 32 when the poppet 28 is located in a seating position and distance to an opening start point between the input port 21 and output port of the poppet 28 are set to the same distance.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a poppet flow control valve for controlling flow using a poppet valve.

[0002]

2. Description of the Related Art FIGS. 7 and 8 show a conventional example of a poppet flow control valve for controlling flow using a poppet valve.

In FIG. 7, 1 is a main valve, and 2 is a variable pilot throttle. The main valve 1 has a valve body 3, and the valve body 3 has an inlet port 4 and an outlet port 5.
And a poppet back pressure chamber 6, a valve seat portion 8 is provided in a passage 7 extending from the inlet port 4 to the outlet port 5, and the valve body 3 is provided with the poppet back pressure chamber 6 from the passage 7.
Is provided with a valve fitting hole 9 which leads to the hole.

A poppet 10 is inserted into the valve fitting hole 9.
A notch 11 is provided on the periphery of the poppet 10, and the seat surface 12 of the poppet 10 is
8, the notch 11 has a small opening of the underlap amount Xun as shown in FIG.

The inlet port 4 of the main valve 1 is connected to the pump 1
The outlet port 5 is connected to the output line 15 via the discharge line 14.

The poppet back pressure chamber 6 of the main valve 1 is connected to an inlet port of the pilot variable throttle 2 via a pipe 16, and an outlet port of the pilot variable throttle 2 is connected to an output pipe via a pipe 17. 15 is connected.

Then, the pilot variable aperture 2 is opened,
The pilot back pressure chamber 6 of the main valve 1 communicates with the outlet port 5 of the main valve 1 through the pilot variable throttle 2 to flow the fluid, so that the difference between the discharge pressure of the pump 13 and the pressure of the poppet back pressure chamber 6 is obtained. To move the poppet 10 away from the valve seat 8 to open the main valve 1 and supply pressure oil from the pump 13 to the outlet side. When the poppet 10 rises, the opening area of the notch 11 increases, and when the difference between the discharge pressure of the pump 13 and the pressure of the poppet back pressure chamber 6 decreases, the poppet 10 descends and stays at a certain fixed position. Thus, the flow rate control is performed.

The flow control characteristic of the poppet flow control valve is determined by the relationship between the opening area between the seat surface 12 and the valve seat 8 of the poppet 10 (hereinafter simply referred to as the opening area of the poppet 10) and the opening area of the notch 11. This relationship is determined by the opening area of the notch 11 at the closed position where the seat surface 12 of the poppet 10 is seated on the valve seat 8, that is, the underlap amount Xun shown in FIG.

[0009] Japanese Utility Model Application Laid-Open No. 62-92301 and Japanese Utility Model Application
In Japanese Patent Publication No. 3-56378, it is proposed to provide an adjusting mechanism for adjusting the opening area of the oil passage corresponding to the notch 11 so that the flow control characteristic of an equivalent poppet flow control valve can be externally adjusted. ing.

[0010]

In the poppet flow control valve shown in FIGS. 7 and 8, when the seat surface portion 12 of the poppet 10 or the valve seat portion 8 on which it is seated wears or deforms due to aging. , The seating position of the poppet 10 changes in the axial direction. For example, the sheet surface portion 1 of the poppet 10
When the valve seat 2 or the valve seat 8 is worn, the seating position of the poppet 10 moves downward, and when the poppet 10 rises due to deformation or a foreign substance adheres, the seating position of the poppet 10 moves upward.
When the seating position of the poppet 10 changes in this way, the opening area (underlap amount Xun) of the notch 11 changes, and the relationship between the opening area of the poppet 10 and the opening area of the notch 11 becomes different. Therefore, there is an inconvenience that a change occurs in the flow control characteristics.

Japanese Utility Model Application Laid-Open No. 62-92301 and Japanese Utility Model Application
In the poppet flow control valve described in JP-A-3-56378, a change in the flow control characteristic can be calibrated by adjusting the opening area of the notch 11 by the adjusting mechanism. However, since the notch 11 is not visible from the outside of the valve, such adjustment work is extremely difficult. In addition, until immediately before the adjustment work, there is abrasion and deformation of the seat surface portion 12 and the valve seat portion 8 up to that time, and a change in the flow rate control characteristic is inevitable.

SUMMARY OF THE INVENTION An object of the present invention is to provide a poppet flow control capable of obtaining an invariable flow control characteristic without special adjustment even when the seating position of a poppet changes due to wear and deformation of a seat surface portion and a valve seat portion of the poppet. Is to provide a valve.

[0013]

In order to achieve the above object, the present invention provides a valve body having an inlet port and an outlet port, and a slidable fit in the valve body, the inlet port and the outlet port. And a back pressure chamber formed in the valve body and biasing the poppet in a closing direction, wherein the poppet communicates the inlet port with the back pressure chamber. A notch for connecting a pilot variable throttle to the back pressure chamber, and actuating the pilot variable throttle to lower the pressure in the back pressure chamber to operate the poppet to control the flow rate in a poppet flow control valve. In the poppet, a restrictor is provided in a passage for communicating the inlet port with the back pressure chamber separately from the flow control notch, and the flow control notch is provided at the seating position of the poppet. The communication between the mouth port and the back pressure chamber is interrupted, the distance between the opening start point of the flow control notch and the opening between the inlet port and the outlet port of the poppet when the poppet is in the seating position. It is assumed that the distance to the start point is set to be the same.

By providing a throttle in the passage separate from the notch for controlling the flow rate as described above, even if the notch for controlling the flow rate is blocked at the seating position of the poppet, the restrictor functions when the pilot variable throttle is opened. Thus, the pressure in the back pressure chamber is reduced, and the poppet can be stroked.

Further, since the distance to the opening start point of the notch for flow control when the poppet is at the seating position and the distance to the opening start point of the poppet are set to be the same, the valve seat portion or the seat surface is worn. Even if the seating position of the poppet changes up and down due to deformation, etc., the distance to the opening start point of the poppet and the distance to the opening start point of the notch for flow control remain the same, and the opening area of the poppet The relationship with the opening area of the notch does not change, and a constant flow control valve is obtained.

[0016]

Embodiments of the present invention will be described below with reference to the drawings.

In FIG. 1, reference numeral 50 denotes a main valve;
Is a pilot variable throttle, and the poppet flow control valve according to the present embodiment is composed of the main valve 50 and the pilot variable throttle 51. The main valve 50 has a valve body 20, and the valve body 20 has an inlet port 21.
, An outlet port 22 and an annular passage 23 extending from the inlet port 21 to the outlet port 22. A valve seat 24 is provided in the passage 23.

A valve fitting hole 25 is formed in the valve body 20, and a poppet back pressure chamber 26 is formed in the valve fitting hole 25. In addition, a connection port 27 communicating with the poppet back pressure chamber 26 is provided in the valve body 20. A poppet 28 is slidably fitted into the valve fitting insertion hole 25, and a seat surface portion 29 is formed in a portion of the poppet 28 which sits on the valve seat portion 24 of the valve body 20. Further, the poppet 28 has a through hole 30 formed along the axis thereof.
A fixed restrictor 31 is formed on the side of the 0 poppet back pressure chamber 26. The inlet port 21 communicates with the poppet back pressure chamber 26 through the through hole 30 of the poppet 28 and the fixed throttle 31. A notch 32 communicating with the through hole 30 is formed in a circumferential portion of the poppet 28.

The inlet port 21 is connected to the discharge side of a pump 33 via a discharge line 34, and the outlet port 22 is connected to a line 35. The connection port 27 is connected to the inlet side of the pilot variable throttle 51 via a pipe 36, and the outlet side of the pilot variable throttle 51 is connected to the pipe 3
8 connects to the conduit 35 via a junction 39.

FIG. 2 is an enlarged view of the notch 32 of FIG. 1. The notch 32 is formed so as to function as a variable throttle with an overlap d1 with respect to the poppet back pressure chamber 26. That is, the end surface 40 of the valve body 20 on the side of the back pressure chamber 26 around the valve insertion hole 25 forms an opening start point of the notch 32 (hereinafter denoted by reference numeral 40), and the poppet 28 further moves from the opening start point 40. The upper wall surface 41 of the notch 32 is formed at a position where it is inserted by d1 in the inlet port direction. Therefore, the notch 32 cuts off the communication between the inlet port 21 and the back pressure chamber 26 in the closed position where the seat surface portion 29 of the poppet 28 is seated on the valve seat 24, and the notch 32 moves when the poppet 28 moves by d1 or more in the direction of the back pressure chamber. Port 21 and back pressure chamber 2
6 functions as a variable aperture that communicates with 6.

FIG. 3 is an enlarged view of a portion of the seat surface portion 29 in FIG. 1. The valve body 20 is formed with a conical inclined portion 24a.
The edge 42 on the side 1 forms an opening start point (hereinafter denoted by reference numeral 42) of the poppet 28, and the end face 43 is positioned on the poppet 28 at a position further inserted by d2 from the opening start point 42 toward the inlet port 21. Is formed. Therefore, the poppet 28 allows the inlet port 21 and the outlet port 22 to communicate only when displaced by d2 or more in the direction of the back pressure chamber 26.

The distances d1 and d2 are set to the same distance d (d1 = d2 = d).

Next, the operation of the poppet flow control valve configured as described above will be described.

When the pilot variable throttle 51 is fully closed, the poppet back pressure chamber 26 is in communication with the inlet port 21 via the through hole 30 and the fixed throttle 31, so that the poppet 28 is shown by the pressure of the poppet back pressure chamber 26. The poppet 28 is urged downward (closed direction), and the poppet 28 is seated on the valve seat 24.

When the pilot variable throttle 51 is opened, the pressure in the poppet back pressure chamber 26 decreases, and the pressure balance between the upper and lower parts of the poppet 28 is lost, so that the poppet 28 moves upward in the drawing to release the pressure oil from the pump 33. The supply is supplied from the inlet port 21 to the outlet port 22, and the notch 32 thereof is opened by the rise of the poppet 28. When the difference between the discharge pressure of the pump 33 and the pressure of the poppet back pressure chamber 26 decreases, the poppet 28 lowers. Stay in a certain position. Thereby, the opening area of the poppet 28 (the seat surface portion 29 and the valve seat portion 24)
The opening area between the pilot variable restrictor 51 is adjusted to a size corresponding to the opening area of the pilot variable restrictor 51, and the flow rate according to the opening area of the pilot variable restrictor 51 is changed from the inlet port 21 to the outlet port 2.
2.

Next, the valve seat portion 24 or the seat surface portion 29 is worn or deformed, and the seating position of the poppet 28 becomes Δd.
Let's consider the case of moving only downward. Poppet 28
The opening starting point 4 of the notch 32
Distance from 0 to upper wall surface 41 (overlap amount) d1
Then, the distance d2 from the opening start point 42 of the poppet 28 to the end face 43 changes to d1 + Δd and d2 + Δd, respectively. However, since d1 = d2 = d, the distance (the amount of overlap) from the opening start point 40 of the notch 32 to the upper wall surface 41 and the distance from the opening start point 42 of the poppet to the end face 4
The distance to 3 remains equal, and the relationship between the opening area of the poppet 28 and the opening area of the notch 32 does not change. Therefore, the flow control characteristics of the flow control valve are unchanged.

Now, this will be described in more detail in comparison with the prior art.

Prior Art Each parameter is placed as shown in FIG. That is, the passing flow rate of the pilot variable throttle 2 is q _y , the displacement of the valve element of the pilot variable throttle is y, the input pressure of the inlet port 4 is p _s , the main flow rate of the poppet 10 is Q _x , and the displacement of the poppet 10 is x, the flow rate through the notch 11 of the poppet 10 is q _c , the pressure in the poppet back pressure chamber 6 is p _c , the output pressure at the outlet port 5 is _pl , the total output flow rate is Q _in , and the input pressure receiving area of the poppet 10 the a _s, the pressure receiving area of the output pressure a _l, the pressure receiving area of the back pressure chamber side of the poppet 10 and a _c. The opening area of the pilot variable throttle 2 is represented by W _y y as being proportional to the displacement y of the valve element of the pilot variable throttle 2 (W _y : constant). When the flow coefficient is set as C _qy , the passing flow rate q _y of the pilot variable throttle 2 is expressed by the following equation.

[0029] _{q y = C qy W y y√} ((2 / ρ) (p c -p 1)) ... (1) In the same manner, the opening area of the notch 11 as being proportional to the displacement x of the poppet 10 W _c x (W _c : constant)
When the flow coefficient is set as C _qc , the notch passing flow rate q _c is expressed by the following equation.

[0030] _{q c = C qc W c (} x + x un) √ ((2 / ρ) (p s -p c)) ... (2) Next, think about the balance of forces in the steady state. Poppet 1
Since 0 stands still at a point where the forces acting in the vertical direction are balanced, the expression is as follows.

[0031] A _s p _s tens _{A l p l = A c p} c ... (3) Furthermore, the relationship between pressure receiving areas, and equal to the A _s tens _{A l = A c ... (4} ). Here, As / Ac = κ is set.

If the compressibility of the fluid is neglected, since q _c = q _y , x + x _un = C _qy W _y √ ((2 / ρ) (p _c -p ₁ )) / C _qc W _{c }} ( _{(2 / ρ) (p s} -p c)) = (C qy W y / C qc W c) √ ((κ / 1-κ) y) That _{is, x + x un = Ky (} K: constant) ... (5 ) then, W _x x and represents the opening area of the poppet 10 as being proportional to the poppet displacement x (W _x: constant), placing the flow coefficient and C _Qx, the main flow rate through Q _x in the following equation expressed.

[0033] _{Q x = C Qx W x x√} ((2 / ρ) (p s -p 1)) ... (6) In addition, the total output flow rate Q _in the main of the passing flow rate Q _x and the pilot variable throttle 2 is equal to the sum of the flow rate through q _y of, the Q _in = Q _x ten q _y ... (7). Here, (5) Substituting formula (6) _{below, Q x = C Qx W x} (Ky-x un) √ ((2 / ρ) (p s -p 1)) ... (8) , and the Considering equation (7), when the value of x _un changes due to wear, deformation, etc., the relationship between the displacement (ie, input) y of the valve element of the pilot variable throttle 2 and the total output flow rate (ie, output) Q _in becomes It will be different from before the change.

Therefore, when this control valve is used to drive the actuator, the expected speed cannot be obtained, giving an uncomfortable feeling to the operator or causing a problem that the control does not work well.

Improvements Made According to the Present Invention The above equations (1), (3), (4) and (7) are the same as in the case (1).

[0036] Placing the opening area of the fixed throttle 31 and the W _c x _0, (2) _{formula, q c = C qc W c} (x-d + x 0) √ ((2 / ρ) (p s -p c )) ... (2A). Similarly (5) _{is, x-d + x 0 =} Ky (K: constant) ... (5A) (6) _{formula, Q x = C Qx W x} (x-d) √ ((2 / ρ) (p _s− p ₁ )) (6A). From (5A) equation formula _{(6A), Q x = C Qx W x} (Ky-x 0) √ ((2 / ρ) (p s -p 1)) ... becomes a (8A), in this case, wear, even if the value of d is varied by deformation, displacement of the valve body of the pilot variable throttle 51 (or input) y and the total output flow (i.e. output) relationship between Q _in is the same as before the change.

Therefore, if this control valve is used for driving the actuator, the problems described in the conventional example will not occur.

The above description is based on the valve seat portion 24 or the seat surface portion 29.
Causes wear, deformation, etc., and the seating position of the poppet 28 becomes Δ
This is the case where the seating position of the poppet 28 has moved upward due to the bulging due to deformation of the valve seat portion 24 or the seat surface portion 29, the attachment of foreign matter, and the like.

FIG. 6 shows an example of use as a direction switching flow control valve in which four of the above flow control valves are combined.

In FIG. 6, a hydraulic pump 100 is connected to an actuator 102 via a direction switching flow control valve 101. The actuator 102 is driven by pressure oil supplied from the hydraulic pump 100, and the supply direction and the supply direction of the pressure oil. The amount is controlled by a directional flow control valve 101. The direction switching flow control valve 101 is switched by a hydraulic pilot operating device 103.

The directional switching flow control valve 101 comprises four poppet flow control valves 110 _IP , 110 _OP and 111 _IP , 111.
_The flow control valves 110 _IP and 110 _OP operate as a pair when the actuator 102 is extended, and the flow control valves 111 _IP and 111 _OP operate as a pair when the actuator 102 contracts.

The poppet flow control valves 110 _IP , 11
Each of 0 _OP, 111 _IP and 111 _OP is composed of a main valve 50 and a pilot variable throttle 51, similarly to the flow control valve shown in FIG. Since the structure of the main valve 50 has already been described, it will not be described here.

The inlet port 21 of the poppet flow control valve 110 _IP is connected to the discharge side of the hydraulic pump 100 via an oil passage 114, and the outlet port 22 is connected to the bottom side of the actuator 102 via an oil passage 115. The inlet port 21 of the flow control valve 110 _OP is connected to the rod side of the actuator 102 via an oil passage 116, and the outlet port 22 is connected to the tank via an oil passage 117. Poppet flow control valve 111 _IP inlet port 21 is oil passage 11
8 is connected to the discharge side of the hydraulic pump 100, and the outlet port 22 is connected to the actuator 102 through an oil passage 119.
And the inlet port 21 of the poppet flow control valve 111 _OP is connected to the actuator 1 through an oil passage 120.
02, and the outlet port 22 is connected to the oil passage 12
1 is connected to the tank.

The hydraulic pilot operating device 103 includes an operating lever 103a and pressure reducing valves 103b and 103c for generating a pilot pressure according to the operation of the operating lever 103a.
And a pressure-reducing valve 103b, 103
c, the pilot pressure generated in each pilot oil passage 1
04a, 104b and 105a, 105b via poppet flow control valves 110 _IP , 110 _OP and 111 _IP , 11
It is guided to a pilot variable diaphragm 51 of 1 _OP . The pilot variable throttles 51 are operated by pilot pressures guided through respective pilot oil passages, and are controlled to have an opening area corresponding to the pilot pressures.

The operation of the hydraulic circuit device thus configured is as follows.

For example, when the operation lever 103a of the hydraulic remote control valve 103 is operated to the S1 side in the figure, the two pressure reducing valves 1
The pressure reducing valve 103b of the valves 03b and 103c operates to generate pilot pressure. This pilot pressure is supplied to the poppet flow control valve 1 via the pilot oil passages 104a and 104b.
It is led to a pilot variable diaphragm 51 of 10 _IP , 110 _OP ,
Thereby, the pilot variable throttles 51 of the poppet flow control valves 110 _IP and 110 _OP open according to the operation amount of the operation lever 103 a, and the poppet 2 of the corresponding main valve 50.
8 open respectively. Accordingly, the pressure oil from the hydraulic pump 100 flows into the bottom side of the actuator 102 via the main valve 50 of the poppet flow control valve 110 _IP , and at the same time, the main valve 50 of the poppet flow control valve 110 _OP from the rod side of the actuator 102. The pressure oil flows into the tank via, which extends the actuator.

On the contrary, the hydraulic remote control valve 103
Is operated to the S2 side in the figure, the pressure reducing valve 103c of the two pressure reducing valves 103b and 103c operates to generate pilot pressure. This pilot pressure is applied to the pilot variable throttles 51 of the poppet flow control valves 111 _IP and 111 _OP via the pilot oil passages 105 a and 105 b.
, Whereby the poppet flow control valve 111 _IP ,
111 _OP pilot variable diaphragm 51
The poppet 28 of the corresponding main valve 50 is opened according to the operation amount of a, and the poppet 28 of the corresponding main valve 50 is opened. Accordingly, the pressure oil from the hydraulic pump 100 flows into the rod side of the actuator 102 via the main valve 50 of the poppet flow control valve 111 _IP , and at the same time, the main valve 50 of the poppet flow control valve 111 _OP from the bottom side of the actuator 102. The pressure oil flows into the tank via, and the actuator contracts.

As described above, when the actuator 102 expands and contracts, the poppet flow control valve 110 _IP ,
Even if the valve seat portion 24 or the seat surface portion 29 of each of the valves 50 of the 110 _OP, 111 _IP , and 111 _OP is worn, deformed, and the like, and the seating position of the poppet 28 changes, the flow control valves 110 _IP , 110 _OP and 11
Since 1 flow control characteristics of _IP, 111 _OP is unchanged, the relationship between the speed of the operation amount and the actuator 102 of the operating lever 103a is also unchanged, good operability is ensured.

The embodiment of the present invention has been described above in the case where the present invention is applied to a specific poppet flow control valve. However, there are various types or variations of the poppet flow control valve, and The same effect can be obtained by applying the present invention to a poppet flow control valve other than the above within the range. For example, in the above embodiment, the side where the end face 43 of the poppet 28 on the side opposite to the back pressure chamber is located as the inlet port, and the side where the annular passage 23 is located as the outlet port, but this may be reversed. Although the pressure receiving area of the poppet 28 also has a A _s tens _{A l = A c ((4} ) formula), A _s ten A
_l and _Ac may not be equal as long as they have a fixed relationship.

[0050]

According to the present invention, in a poppet flow control valve for controlling a flow rate using a poppet valve, even if a valve seat portion or a seat surface portion is worn or deformed and the seating position of the poppet is changed, Invariable flow control characteristics can be secured without special adjustment.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view of a poppet flow control valve according to an embodiment of the present invention.

FIG. 2 is an enlarged view near a notch of the flow control valve shown in FIG. 1;

FIG. 3 is an enlarged view of the vicinity of a seat surface portion of the flow control valve shown in FIG.

FIG. 4 is a diagram for explaining a flow control characteristic of a conventional poppet flow control valve.

FIG. 5 is a diagram for explaining a flow control characteristic of the poppet flow control valve of the present invention.

6 is a circuit diagram showing an example of use as a direction switching flow control valve in which the flow control valve shown in FIG. 1 is combined.

FIG. 7 is a sectional view of a conventional poppet flow control valve.

FIG. 8 is an enlarged view near a notch of a conventional poppet flow control valve.

[Explanation of symbols]

 Reference Signs List 20 valve body 21 input port 28 poppet 31 fixed throttle 32 notch 33 pump 37 pilot variable throttle 40 notch opening start point 42 poppet opening start point

Claims (1)

[Claims] 1. A valve body having an inlet port and an outlet port, a poppet slidably fitted into the valve body to adjust communication between the inlet port and the outlet port, and formed in the valve body. A back pressure chamber for urging the poppet in the closing direction, a notch for flow control that connects the inlet port to the back pressure chamber is formed in the poppet, and a pilot variable throttle is provided in the back pressure chamber. A poppet flow control valve that is connected to lower the pressure in the back pressure chamber by operating the pilot variable throttle to operate the poppet to control the flow rate, wherein the poppet has an inlet port separate from the flow rate control notch. Is provided with a throttle in a passage communicating with the back pressure chamber,
And the flow control notch is configured to cut off the communication between the inlet port and the back pressure chamber at the seating position of the poppet, and to the opening start point of the flow control notch when the poppet is at the seating position. And a distance between the inlet port and the outlet port of the poppet to an opening start point is set to be the same.