JPH0434289Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] This invention relates to a seat valve that is provided in a hydraulic system and controls the flow rate of hydraulic oil.

[Conventional technology]

In a seat valve, for example, a conical seat is formed on the valve body, and this seat is moved close to or away from the valve seat to adjust the opening area between the valve body and the valve seat, and the flow rate is adjusted according to the opening area. An example of this is shown in FIG. 3.

FIG. 3 shows a typical seated valve used to control the flow of fluid between inlet port A and outlet port B. FIG.

This seat valve includes a valve body 1, a case 2 that accommodates the valve body 1 in a reciprocating manner, and a spring 4 that constantly urges the valve body 1 toward the inlet port A within a valve chamber 3 formed within the case 2. It is mainly composed of. A seat portion 5 is formed on the inlet port A side of the valve body 1, and a seat surface 6 is formed in a portion of the case 2 corresponding to the seat portion 5, and a seat surface 6 is formed on the side of the valve body 1 opposite to the inlet port. 3 has a valve back pressure chamber 7 formed therein. An operating conduit 8 is led from the inlet port A, and a back pressure applying conduit 9 is communicated with the valve back pressure chamber 7. The operating conduit 8 is also provided with a fixed aperture A ₀ and a variable aperture A ₁ whose aperture opening changes depending on the amount of operation from the operating section C ₁ ,
By adjusting the back pressure P _c of the valve body 1 with respect to the pressure P _s of the inlet port A, the valve can be opened and closed.

However, in the above-mentioned seat valve, the position of the valve body 1 changes when the back pressure P _c is directly affected by the circuit pressure, that is, the pressure P _s at the inlet port A.
-Can only be used as an OFF type valve.

Therefore, in the seat valve as described above,
In order to obtain a valve displacement corresponding to the amount of operation from the operating portion _C1 , it is necessary to feed back the valve displacement to the throttle _A0 or the throttle _A1 .

An example of this is shown in FIGS. 4 and 5. FIG. 4 shows that the position of the valve is fed back from the valve body 1 to the variable throttle _A1 through the link mechanism 10,
In the case of FIG. 5, the position of the valve is fed back to the throttle A ₀ in FIG. 3 via the link mechanism 10.

Note that the configurations in FIGS. 4 and 5 can be considered to be the same as in FIG. 3, except for the fact that the operating conduit 8 communicates with the outlet port B and the feedback mechanism by the link mechanism 10. Therefore, each component is given the same reference numeral, and a description thereof will be omitted here.

Next, the proportionality due to the feedback of the seat valve in FIG. 5 will be explained.

Here, the pressure at the inlet port A of the valve body 1 is P _s , the pressure receiving area is A _s , the pressure at the outlet port B is P _r , the pressure receiving area is A _r , the pressure in the valve chamber 7 is P _c , and the pressure receiving area is A _c , A _c = A _s + A _r ...(1) κ = A _s /A _c ...(2) P _c・A _c =P _s・A _s +P _r・A _r ...(3) From the relationship, P _s − P _c = (1 − κ) (P _s − P _r ) ……(4) P _c − P _r = κ (P _s − P _r ) ……(5) , the hydraulic pressure acting on valve body 1 is balanced.

On the other hand, when the displacement of the aperture A ₁ is y, the position of the valve body 1 is fed back to the aperture A ₀ by a signal from the operating part C ₁ , and if the displacement is x, then the aperture A ₀
The flow rate q _AO passing through is calculated as follows, where the flow coefficient is C _AO and the flow path area is w _c・x, q _AO = C _AO・w _c・x・√2√ _s − _c ……(6) The aperture A ₁ The passing flow rate q _A1 is calculated using the flow coefficient as C _A1 channel area wy・y: q _A1 = C _A1・wy・y・√2√ _c −√
...(7), and since there is a relationship between the flow rates q _A0 and q _A1 , q _AO = q _A1 ...(8), becomes. Then, by substituting the relationships (4) and (5) into the above equation, we get Therefore, the displacement x of the valve body 1 is the displacement y of the variable orifice _A1
is proportional to.

Utilizing this principle, the structure of the seat valve in which the functions of the orifice A ₀ and the feedback link 5 shown in FIG.
As shown in the figure. In the seat valve shown in FIG. 6, an operating conduit 8 is guided from the valve back pressure chamber 7 to the outlet port B, a variable throttle _A1 is inserted into the operating conduit 8, and the valve operating section C ₁ allows you to control the aperture. In addition, a slit 11 having a width W _and a depth H is cut in a predetermined portion of the outer circumference of the valve body 1 in the axial direction, and communicates the valve chamber 3 on the inlet port A side with the valve back pressure chamber 7. .

With this configuration, the aperture in Figure 5
A feedback path for A ₀ communicates with the valve chamber 3 on the inlet port A side and the valve back pressure chamber 7 through the slit 1.
1, and as the valve opening degree (lift amount of the valve body 1) increases, the flow rate passing through the slit 11 and flowing toward the valve rear chamber 7 side also increases. However, in order to achieve proportionality with this slit 11, the relationship between the depth H and the front stroke S of the valve body 1 needs to be H>S. Otherwise, a region defined by the depth H will occur in the flow path area, which will impair proportionality.

[Problem that the invention attempts to solve]

By the way, in the seat valve having the feedback function using the slit 11 described above, the width W _c of the slit is approximately 1 mm in the example shown in FIG.
In order to process the groove so as to maintain the relationship H>S with this width, a special manufacturing technique such as electrical discharge machining is required. Furthermore, when the valve body 1 is seated, the opening area of the slit 11 opening toward the valve back pressure chamber 7 side, in other words, the opening area 〓 x ₀ during the opening toward the valve back pressure chamber 7 side must be controlled with precision. If the seat portion 5 of the valve body 1 has to be _a flat sheet, that is, when the above interval _〓 As a result, if the interval 〓x ₀ is too large, a large dead zone will be created between the input y and the valve displacement x, which may cause problems in following the input operation from the operating section _C1 .

This idea was made in view of the above technical background, and its purpose is to make it possible to adjust the opening area corresponding to the above distance x ₀ without requiring special processing methods or precise processing accuracy. Accordingly, it is an object of the present invention to provide a seat valve having a feedback function capable of adjusting a dead zone.

[Means for solving problems]

In order to solve the problems faced by the prior art and achieve the above object, the seat valve of this invention has a valve back pressure chamber having a valve back pressure receiving area equal to the sum of the valve inlet pressure receiving area and the valve outlet pressure receiving area. A valve body is reciprocatably housed in the valve chamber, and an oil passage is formed that communicates the valve chamber, the valve inlet, and the valve back pressure chamber, and allows the opening area to change according to the displacement of the valve body. and an adjusting means capable of adjusting the opening area of the oil passage independently of the displacement of the valve body from the outside of the valve chamber.

[Effect]

According to the above means, an oil passage for feedback is formed in the valve body itself, and feedback corresponding to the amount of displacement of the valve body itself can be applied to the valve body without using a link mechanism in particular. That is, when the valve body is seated on the valve seat, the amount of oil flowing to the valve back pressure side can be adjusted by the adjusting means. As a result, the dead zone area when the valve body is seated can be set arbitrarily depending on the application, and special processing or high processing accuracy is not required to set the opening area of the feedback path when the valve body is seated. .

〔Example〕

An example of an embodiment of this invention will be described below based on the drawings.

Figures 1 and 2 are for explaining a seat valve according to an embodiment of this invention. Figure 1 is an explanatory diagram of the seat valve, and Figure 2 shows an adjustment section of an oil passage for feedback. It is an enlarged cross-sectional view of the main parts of the seat valve. In FIGS. 1 and 2, the same reference numerals are given to the components that are the same as or can be considered to be the same as those of the conventional Zero, and the explanations regarding these parts are meant to avoid duplication. I will omit it here.

In FIG. 1, a plurality of communication holes 12 are formed from the valve chamber 3 on the inlet port A side of the valve body 1 of the seat valve to the valve back pressure chamber 7 side, and are integrated into one at the center position. It opens into the valve back pressure chamber 7.
The communication hole 13 that opens toward the valve back pressure chamber includes a large diameter portion 15 whose lower end is larger in diameter than the other in the figure, a shaft portion 16 with a smaller diameter, and a space between the large diameter portion 15 and the shaft portion 16. The rod 14 has a tapered portion 17 formed in the rod 14.
is inserted. The rod 14 is attached by screwing a threaded portion 18 formed at the upper end into a portion of the case 2 facing the communication hole 13, and a nut 19 is screwed onto the portion protruding from the case 2. ing. Therefore, when the nut 19 is loosened and the rod 14 is rotated, the large diameter portion 15 and the tapered portion 17 can be moved forward and backward within the communication hole 13. Thereby, a variable diaphragm is formed between the tapered portion 17 and the inner wall of the communication hole 13. All other parts are constructed in the same or equivalent manner as in the conventional example described above.

Therefore, in the seat valve configured as above, the flow rate passing through the orifice A ₀ corresponding to equation (6) is
q _AO is q _AO = C _AO (π・dsinθ)x・√2√ _s − _c where d is the diameter of the large diameter portion 15 of the rod 14 and θ is the taper angle of the tapered portion 17.
...(6)-1 By appropriately selecting the diameter d and the taper angle θ, the same valve function as the seat valve shown in FIG. 5 can be obtained.

Furthermore, since the opening area of the oil passage for the aforementioned feedback, that is, the opening area of the communication hole 13, can be adjusted by advancing and retracting the rod 14, the most appropriate rod position can be arbitrarily set depending on the application of the seat valve.

This will be explained in detail using mathematical formulas. In other words, using equations (3), (6), (7) and (8), the inlet pressure is
Consider what happens to the valve displacement x when P _s changes. Here, it is assumed that the back pressure P _r does not change. Equation (3) is: (P _c + ΔP _c ) A _c = (P _s + ΔP _s ) A _s + P _r A _r ΔP _c A _c = ΔP _s From A _s , ΔP _c = (A _s /A _c )ΔP _s = κΔP _s .

Equation (6) is: q _AO + Δq _AO = C _AO・w _c (x+Δx)√2√( _s +
_s ) − ( _c + _c ) = C _AO・w _c √2 (+) √ ( _s − _c ) {1
+( _s − _c ) ( _s − _c )} =C _AO・w _c √2√ _s − _c (+)√1+(
_s − _c ) ( _s − _c )……(10) ≒C _AO・w _c √2√ _s − _c (+) {1+(
1/2) (ΔP _s −ΔP _c )/(P _s −P _c )}……(11) =C _AO・w _c √2√ _s − _c {x+Δx+(1/2
)x(ΔP _s −ΔP _c )/(P _s −P _c )+(1/2)(ΔP _s −

ΔP _c ) (P _s −P _c )Δx} ...(12) ≒C _AO・w _c √2√ _s − _c {x+Δx+(1/2
)x(ΔP _s −ΔP _c )/(P _s −P _c )}……(13) =q _AO +(q _AO /x)Δx+{q _AO /2(P _s −P _c )}(Δ
P _s −ΔP _c ), therefore, Δq _AO = (q _AO /x)Δx+{q _AO /2(P _s −P _c )}(Δ
P _s −ΔP _c )...(14) However, in inducing Δq _AO , (10)
In the equation, (ΔP _s −ΔP _c )/(P _s −P _c )<<1 was considered and √ was expanded to derive equation (11). Also,
In equation (12), (ΔP _s −ΔP _c )Δx is a minute multiplication, so it is ignored, and equation (13) is derived.

Assuming that y is not moved, equation (7) becomes Δq _A1 = {q _A1 /2 (P _c − P _r )} ΔP _c (15) using the same procedure as the above derivation.

In addition, since equation (8) assumes that the valve body 1 moves, A _c (dΔx/dt) = Δq _A1 − Δq _AO , and Δq _AO derived from equations (14) and (15),
Substituting Δq _A1 , A _c (dΔx/dt) = {q _A1 /2(P _c − P _r )}ΔP _c − (q _AO
/x)Δx−{ _qAO /2( _Ps − _Pc )}( _ΔPs − _ΔPc ). Furthermore, if we transform this, A _c (dΔx/dt)+(q _AO /x)Δx={q _A1 /2(P _c −P
_r )}ΔP _c − {q _AO /2(P _s −P _c )}(ΔP _s −ΔP _c ) = {q _A1 /2(P _c −P _r )}ΔP _c + {q _AO /2(P _s − _Pc )
}ΔP _c + {q _AO /2 (ΔP _s −ΔP _c )}ΔP _s . Here, if we set q _A1 = q _AO , A _c (dΔx/dt) + (q _AO /x) Δx = (q _AO /2) {1
/(P _c −P _r ) +1/(P _s −P _c )}ΔP _c −{q _AO /2(P _s −P _c )}ΔP
_s = (q _AO /2) [{(P _s − P _c ) + (P _c − P _r )} / {(P
_c −P _r )(P _s −P _c )}]ΔP _c −{q _AO /2(P _s −P _c )}Δ
P _s = (q _AO /2) [(P _s −P _r )/{(P _c −P _r )(P _s −P _c
)}]κΔP _c − {q _AO /2 (P _s − P _c )}ΔP _s = (q _AO /2) {(1/κ) / (P _s − P _c )}κΔP _c −
{q _AO /2(P _s −P _c )}ΔP _s = {q _AO /2(P _s −P _c )}ΔP _s −{q _AO /2(P _s −P _c )
}ΔP _s =0. Therefore, if the relationship ΔP _c =κΔP _s is established instantaneously due to the balance of the forces of the valve, the valve displacement Δx will be 0 and will not be affected by disturbance.

However, for example, the balance relationship of the valve force is w (d ² Δx/dt ² ) + b (dΔx/dt) + hΔx = (P _s + Δ
P _s ) A _s + P _r A _r − (P _c + ΔP _c ) A, etc., the relationship ΔP _c = κΔP _s does not hold instantaneously, but
After a certain period of time has elapsed, the valve displacement Δx is statically determined to be 0.

As can be seen from the balance of forces described above, the valve body 1 operates as follows. That is, the aperture
When A ₁ is closed by operating the operating part C ₁ , the pressure on the outlet port B side is zero, and the valve body 1 is closed by the pressure from the valve back pressure chamber 7 into the seat part 5 .
is pressed against the seat surface 6, and the space between the inlet port A and the outlet port B is closed. From this state, operate operation section _C1 to adjust the aperture.
When _A1 is opened by a predetermined amount, hydraulic oil flows from the valve back pressure chamber 7 side to the outlet port B side through the operation pipe 8, and the pressure on the outlet port B side increases. As a result, the valve body 1 is separated from the seat surface 6, and the inlet port A
Hydraulic oil flows from the outlet port B to the outlet port B according to the opening degree of the valve body 1. On the other hand, when the valve body 1 rises, the taper part 1
7 and the inner wall of the communication hole 13 becomes larger, and the pressure in the valve back pressure chamber 7 becomes higher. Then, the valve body 1 stops at a position where the sum of the forces applied to the valve body 1 from the back pressure from the valve back pressure chamber 7 and the elastic force of the spring 4 becomes equal to the force applied to the valve body 1 from the outlet port B side. . At this time, the position of the valve body 1 is fed back by the throttle between the tapered portion 17 and the inner wall of the communication hole 13, and the valve displacement is statically determined without being subjected to any disturbance as described above. It goes without saying that this stop position, that is, the displacement x of the valve body 1, is proportional to the displacement y of the variable throttle _A1 according to the amount of operation of the operation part _C1 , as described above.

As described above, according to the above embodiment, a seat valve with equivalent functions can be manufactured without requiring special processing or high-precision processing, and the feedback orifice is adjustable. Therefore, there is no need to accurately set the opening area of the oil passage for feedback when the seat valve opening is zero, and there is no longer a need to limit the seat portion of the seat valve to only a flat seat type. Furthermore, by changing the dimensions of the large diameter part of the rod, the angle of the tapered part, etc., valves with various characteristics can be obtained. It can be applied to equipment, and in addition, the dead zone can be easily adjusted.
It is possible to provide a proportional control valve with good operability, and it is possible to reliably produce multiple pieces of the same product.

[Effect of idea]

As is clear from the above description, according to this invention, a feedback oil passage is formed that communicates the valve inlet and the valve back pressure chamber, and the oil passage is configured to be adjustable from outside the valve body. Since the opening area of the oil passage can be freely set, there is no need for special processing or precision when setting the oil passage, and it can be manufactured at low cost, and the dead zone can be adjusted. Therefore, one seat valve can be used for various purposes, and good proportionality can be obtained in the valve itself.

[Brief explanation of the drawing]

1 and 2 are for explaining an embodiment of this invention, FIG. 1 is an explanatory diagram of a seat valve according to the embodiment, FIG. 2 is an enlarged explanatory diagram of the main part,
FIG. 3, FIG. 4, FIG. 5, and FIG. 6 are explanatory views of conventional seat valves, respectively. 1... Valve body, 2... Case, 3... Valve chamber, 5...
... Seat part, 6... Seat surface, 7... Valve back pressure chamber,
8... Operation pipe line, 9... Back pressure applying pipe line, 12,
13...Communication hole, 14...Rod, 15...Large diameter part, 16...Shaft part, 17...Tapered part, 18...
Threaded part, 19... Nut, A... Inlet port, B
...Exit port.

Claims (1)

[Scope of claim for utility model registration] A valve chamber including a valve back pressure chamber having a valve back pressure receiving area equal to the sum of the valve inlet pressure receiving area and the valve outlet pressure receiving area, and the valve inlet portion and the valve back pressure chamber communicating with each other. , an oil passage is formed that allows the opening area to change according to the displacement of the valve body,
A valve body is housed in the valve chamber so as to be able to reciprocate; and an adjusting means that can adjust the opening area of the oil passage from outside the valve chamber independently of displacement of the valve body. seat valve.