JPS61252905A - Servo valve - Google Patents

Abstract

PURPOSE:To make the functions of a servo valve alterable, by connecting an outlet of a first servo valve to a first liquid outlet and an outlet of a third servo valve, and also an outlet of a second servo valve to a second fluid outlet and an outlet of a fourth servo valve, respectively. CONSTITUTION:An outlet 512 of a first servo valve 11 is connected to a first fluid outlet 5 and an outlet 712 of a third servo valve 13 each. Likewise, a control port 711 of the third servo valve 13 is connected to a fluid discharge port 7 of a servo valve. Then, an outlet 612 of a second servo valve 12 is connected to a second fluid outlet 6 and an outlet 812 of a fourth servo valve 14 each, and a control port 811 of the fourth servo valve 14 is connected to a fluid discharge port 8 of a servo valve. With this constitution, alteration of its functions from underlapping to overlapping in the midway of operations of a hydraulic actuator is performable.

Description

DETAILED DESCRIPTION OF THE INVENTION "Field of Industrial Application" The present invention relates to servo valves used for hydraulic and pneumatic systems.

"Prior Art" A servo valve conventionally used for electrically controlling a double-acting fluid pressure actuator has a first fluid outlet 103 and a second fluid outlet, as shown in FIG. 1
Controls 04. That is, if the first fluid outlet 103 is discharging fluid.

In conjunction with this, the fluid at the second fluid outlet 104 was discharged.

As shown in FIG. 2, an electric actuator 120 that changes the driving force depending on the magnitude of the current is connected to one spool 110 (direct mechanical connection or force amplification through control of fluid pressure). 2) If the electrical input is at an intermediate value, the first land 111 and the second land 1 are connected as shown in the figure.
12 both communicate with the first fluid outlet 103 ) 115
and covers the boat 116 communicating with the second fluid outlet 104, and if the electric power were to drop, the upward thrust of the spring 130 would prevail, the spool 110 would move up, and the fluid in the fluid population 102 would be transferred to the boat. 116 is the second land 112
The second fluid outlet 10 is spaced apart by the upward movement of the
4, and the fluid at the first fluid outlet 103 was configured to flow out to the first fluid outlet 105.

Although such a structural configuration is simple in structure, it is difficult in terms of engineering, and it is difficult to precisely position the first land 111 to exactly cover the boat 115 and the second land 112 to exactly cover the boat 116. The key to manufacturing such servo valves is to manufacture them with high dimensional accuracy so that they meet the required specifications, which is very time-consuming and expensive.

Also, 1st. Each of the second lands 111 and 112 is a bow)
115, 116 in each of the first lands 1
11 and the second land 1120 width and bow) 115 and 116 are the same width as zero wrap.

When the width of the land is larger than the width of the boat, it is called overlap, and when the width of the land is smaller than the width of the boat, it is called underlap. Currently, wrap, overlap, and underlap products are used separately.

FIG. 3 shows a connection diagram of a conventional servo valve 301 and a fluid pressure actuator 350 using JISBO 125 hydraulic/pneumatic diagram symbols.

"Problems to be Solved by the Invention" The present invention was invented to solve the above-mentioned problems of the conventional art. Today,
In line with the current situation where highly complex electrical signal processing is performed and the control signals can be changed at high speed and frequently, it is not affected by the precision of the work, and it is possible to perform zero overlap, overlap, underlap, etc. There is no need to use it separately, it is easy to work, the range of use and the limits of application are greatly expanded compared to conventional ones, and the control performance is better than that of conventional products. It becomes possible to use a method of changing the function of a servo valve, for example from underlap to overlap, during actuator operation, contributing to more precise control of fluid pressure actuators than before. Our goal is to provide servo valves that can.

``Means to solve the r problem'' A concise representation of the invention is shown in FIGS. 1 and 4.

By comparing FIG. 3 and FIG. 4, the gist of the present invention can be easily understood.

A detailed explanation of FIG. 4 will be given later together with the explanation of FIG. 1.

In order to facilitate understanding, the explanation will be made using two drawings, top and bottom, left and right, and front and back. In actual practice, it goes without saying that even if the device is inverted, left-right symmetrically turned over, etc., the structure does not deviate from the essence of the invention.

FIG. 1 shows a preferred embodiment of the present invention.

Moreover, it simply shows means for solving the problem targeted by the present invention.

Let's explain about Figure 1.

FIG. 1 is a cross-sectional view of a preferred embodiment of the present invention, and 2 is a main body, the lower part of which is connected to a scissor sub-base 3.

The sub-base 3 is provided with a fluid port 3 in the center as shown.

A first fluid outlet 5 is provided on the left side of the fluid population 3, and a second fluid outlet 6 is provided on the right side of the fluid population 4 as shown.

9 is a drain hole.

As shown in the figure, the main body 2 includes third two-port servo valves 13 in order from left to right. First 2-port servo valve 11
．． A second 2-port servo valve 12 and a fourth 2-port servo valve 14 are installed as shown.

Of these, the first. Second. $3. The fourth two-port servo valves 11, 12, 13, and 14 have the same structure as those shown in Fig. 1, but there are differences in size and structure depending on the purpose. However, the gist of the present invention remains unchanged.

FIG. 5 is for explaining the detailed structure of the first two-port servo valve 11 used in FIG. FIG. 2 is a side cross-sectional view of a state in which the first two-port servo valve 11 is installed.

501 is a spool, which is tapered at the center as shown in FIG. 9, and has second lands 503 at the top and bottom as shown.
A first land 504 is provided. In this example, the spool is a valve.

A sleeve 510 is provided on the outside of the spool 501,
The inner hole 511 of the sleeve 510 is the first. 2nd land 502
, 503, and the spool 501 is provided so that it can freely slide up and down.

The sleeve 510 is provided with a control port 511 at the bottom,
The spacing size and position are such that it is covered by the first land 504.

An outlet 512 is provided in the sleeve 510 at an intermediate position between the first land 504 and the second land 503 as shown.

As shown in FIG. 9, the sleeve 510 is provided with O-rings 513, 514 and 515, respectively, in order to prevent fluid leakage between the control port 511 and the outlet 512 between the sleeve 510 and the main body 2. ing.

An electric actuator 520 is provided above the sleeve 510 as shown.

The electric actuator 520 has a lower iron core 5 made of soft magnetic material.
21. The outer periphery is surrounded by a case 522, and above the case 522 is an electric actuator 52.
The upper sleeve 623, which is a hollow cylindrical soft magnetic material, is provided in the center of the cylinder 0.

Further, at the upper center of the lower iron core 521, a hollow cylindrical lower sleeve 524 made of soft magnetic material is provided as shown.

A gap 525 is provided between the lower end of the upper sleeve 523 and the upper end of the lower sleeve 524 as shown in the figure.

A movable piece 526 made of soft magnetic material is installed inside the hollow cylindrical upper sleeve 523 so as to be able to slide up and down.
30, the vertical thrust of the movable piece 526 can be transmitted to the spool 501 through the lower iron core 521.

A spring 531 is provided at the lower end of the spool 601 to position the spool 501 at a position where the upward thrust is balanced with the downward thrust of the movable piece 526.

A coil 527 is provided inside the case 522 as shown in the figure, and the magnitude of the magnetic flux acting on the lower end of the movable piece 526 located in the gap 525 changes depending on the strength of the current applied to the coil 527. The thrust exerted downward is varied.

At the position of the movable piece 526 shown in FIG. The positions are made to match.

The above-mentioned coincidence of the electrical input value and the position is achieved when sophisticated control is possible in which the electrical input value can be controlled to a position where the upper edge of the first land 504 and the upper edge of the control port 511 can be made to coincide with each other. It is not necessary that the upper edge of the first land 504 and the upper edge of the control port 511 coincide with each other for a predetermined current value.

Current computer control is capable of freely controlling electrical input values, and this is a major advantage of the present invention.
(first land 111 and bow in the figure) 115. Furthermore, in contrast to the servo valve in which the second land 112 and the boat 116 had to be aligned, the present invention has the upper edge of the first land 504 and the control port 511 for a constant electric power value. The simple precision of simply aligning the upper edges of the two is sufficient, and this type of method does not require the precision of two-way machining as in conventional methods.

This can be accomplished by simple means that are used to adjust any conventionally known equipment, such as simply adjusting the thrust of the spring 531 using a screw or the like, or adjusting the length of the valve stem 530 using a screw or the like. I can do it.

Furthermore, the present invention has an unprecedented feature in that if the electrical human power value can be adjusted, the above-mentioned adjustment is not even necessary.

FIG. 5 529 shows the top cover of the electric actuator 520.

Now, let's return to Figure 1 and continue the explanation.

The first two-port servo valve 11 shown in FIG.
Although the structural configuration has been explained with reference to FIG. 5, the second two-port servo valve 12 also has the same structural configuration.

If it is necessary to display each part of the second servo valve 12, add 100 to the number used in the structural configuration of the first 2-port servo valve 11 in FIG. Although it was 501 in this case, it will be expressed as 601 in the second servo valve 12.

Further, for the third 2-port servo valve 13, 200 is added, and for the fourth 2-port servo valve 14, 300 is added.For example, the sleeve of the fourth 2-port servo valve 14 is numbered 810. do.

Therefore, in FIG. 1st. Second. 3rd, 4th
Please allow me to explain the two-port servo valves 11, 12, 13, and 14 using the minimum necessary representation.

20 in FIG. 1 is a through hole which connects the fluid port 4 to the control port 511 of the first 2-port servo valve and the second port 20 as shown in FIG.
It communicates with the control port 611 of the two-port servo valve.

Reference numeral 21 denotes a through hole, and the through hole 21 communicates with the first fluid outlet 5, the outlet 512 of the first two-port servo valve 11, and the lower outlet 12 of the third two-port servo valve 13.

The control lower 11 of the third two-port servo valve 13 is adapted to communicate with the fluid discharge lower.

The through hole 22 communicates with the second fluid outlet 6 and also communicates with the second fluid outlet 6.
The control port 8 of the fourth two-port servo valve 14 communicates with the outlet 612 of the two-port servo valve 12 and the outlet 812 of the fourth two-port servo valve 14 .
11 communicates with the fluid outlet 8 .

When such a structural configuration is expressed using JISBO125 hydraulic/pneumatic diagram symbols, it becomes as shown in Fig. 4.

"Action" Now, each electric actuator 520, 620.720
, 820, the upper edge of each control port 511, 611, 711° 811 and the first
The first. Second. Third. Assuming that a fourth two-port servovalve 11.12, 13.14 is used, this lowest electrical input value is similar to the neutral position of the conventional servovalve shown in FIG. .

If the electrical power value is slightly more than the lowest electrical input value, each of the 2-port servo valves 11, 12, 13
, 14 open slightly, which is similar to the underlapping and neutral position of conventional servo valves. Also, the first and fourth two-port servo valves 11 and 1
4 (referred to as the first group) is larger than the lowest electrical input value, the fluid flows out to the first fluid outlet 5,
The fluid at the second fluid outlet 6 flows out to the fluid outlet 8 . The flow rate is proportional to the applied electrical input value.

The first and fourth two-port servo valves 11 and 14, that is, the electric input value of the first group is the lowest electric power value, and the second and third two-port servo valves 12 and 13 (referred to as the second group) When the electric power value of is increased above the minimum value, the fluid flows out to the second fluid outlet 6 and the fluid at the first fluid outlet 5 flows out to the fluid discharge lower.

The flow rate is proportional to the electric power value applied to the two-port servo valves 12 and 13.

In this way, by alternately applying electric input values to the first group of electric actuators 520 and 820 and the second group of electric actuators 620 and 720, the same control as a conventional servo valve can be performed.

Moreover, regarding the time given to the first group and the second group, if the electric input value of the second group is not increased at the same time as the first group is set to the minimum value, but is given to the second group after a little time, The effect is similar to the underlap effect in conventional servo valves, and both underlap and overlap characteristics can be achieved with one servo valve depending on how the control electrical input value is applied.

Moreover, conventionally the first fluid outlet 103 is the supply source.

The second fluid outlet 104 has become necessary due to the displacement 9
In the case of the present invention, when an electrical input value is simultaneously applied to the first group and the second group (or when the electrical input value is decreased), the supply (or discharge) amount is increased to the first fluid outlet 5, and the Control such as supplying (or discharging) the amount to the two fluid outlets 6 can also be made freely, making it possible to perform wider control possibilities, more precise control, and higher quality control than conventional systems.

This is especially true for compressible gases.

For example, the piston 3 of the actuator 380 is not necessarily a servo valve that exhausts the rear chamber 382 while supplying air to the front chamber 381 of the actuator 380 shown in FIG.
83 moves to the right, the gas in the rear chamber 382 is first removed and air is supplied to the front chamber 381, or the front chamber 381 is
In many cases, it is preferable for control purposes to vary the amount of gas exhausted by the rear chamber 382 in relation to the amount of air supplied to the rear chamber 382. Although this type of use was not possible with conventional servo valves, the present invention makes it possible to do so. achievable.

Embodiment One preferred embodiment has already been described in the description of the operation, and in the one shown in FIG. 6, the electric actuator 520 directly drives the spool 501.

Such a structural configuration is preferable for small-sized devices, but for large-sized devices, the electric actuator 5
20 is large, and therefore the electric power value is also large, making control difficult.

Therefore, the electric actuator controls a small amount of fluid with a small electric power value, and the controlled small amount of fluid controls the main valve. So-called pilot type valves are commonly used in conventional valves and have become a common technology. Even if a two-port servo valve, which is an element of the present invention, uses such a structure. There are no problems.

FIG. 8 shows an embodiment of a two-port servo valve using such means, and the electric actuator 520 in FIG. 8 is the same as that in FIG. 5.

However, the spring is housed in the lower part of the movable piece 526, as shown at 560, so that the position of the valve stem 530 can be determined in balance with the downward thrust of the movable piece 526.

Furthermore, the spool 501 and the sleeve 510 are also substantially the same, and their structural configurations remain the same.

In the one in FIG. 8, from the two holes 20 as shown,
A guide hole 551 is provided with one end looking into the through hole 20.

The guide hole 551 is inside the main body 2 as shown.

Look through the crest 522 and onto the flapper valve seat 553.

The flapper valve seat 553 and the inflow hole 554 are configured to communicate with each other.

The inflow hole 554 is configured to allow the fluid in the through hole 20 to be introduced into the spool pressure chamber 556 at the upper part of the spool 501 .

A flapper chamber 561 is formed in the space where the upper valve rod 530 of the flapper valve seat 553 exists, and the flapper chamber 561 is communicated with the fluid discharge lower through a guide hole 555.

The lower end of the valve stem 530 is configured to cover the flapper valve seat 553.

Furthermore, the aperture needle 557 may be provided in the aperture section 552 to adjust the degree of aperture.

In such a structural configuration, when the electric input value given to the electric actuator 620 increases and the downward thrust of the valve stem 530 increases, the amount of fluid that escapes from the flapper valve seat 553 through the flapper chamber 561 and into the guide hole 555 decreases. death,
The pressure of the fluid passing through the constriction portion 552 increases, that is, the pressure in the spool pressure chamber 556 increases, and the degree of opening of the control port 511 increases.

When the electrical input value applied to the electric actuator 520 is decreased, the amount of fluid passing from the flapper valve and seat 553 to the flapper chamber 561 increases, the pressure in the spool pressure chamber 556 decreases, and the degree of control loop 5110 decreases.

Such an action of the throttle portion 552 and the flapper valve seat 553 is well known as a nozzle-flapper action.

In addition, the control pressure, that is, the pressure appearing in the two through holes 21, is guided to the piston 541 through the guide hole 540, as shown by the dotted line in Figure 6, and the spring 531 is controlled up and down by the pressure, so that the control electric human power value and the control pressure are constant. It is conventionally known that a pressure feedback method is also used to close the control port 511 when the interphase is established.

Also, electric actuators 520, 620, 720.82
0 is not limited to those mentioned above, but is used in conventional servo valves. Any conventionally known type may be used, including a moving coil type, a 9-rotation displacement type, and a 9-bending deformation type (see References, for example, 9, published by Nikkan Kogyo Shimbun, Hydraulic Valve Handbook, page 228). There isn't.

Further, even if piezoelectric ceramics or plastic piezoelectric elements, which have recently appeared, are used as electric actuators, this will not impede the implementation of the present invention.

"Effects of the Invention" As already explained in detail in the above explanation, although the conventional servo valve appears to have a simpler structure than the one of the present invention, it is difficult to construct the first land. 111
If the ball just covers 115, then the second land 11
The key to manufacturing such servo valves is to manufacture these servo valves with high precision in two dimensions so that 2 is in a precise position that covers the boat 116 evenly, which is extremely time-consuming and expensive. It was something.

Also, 1st. Each of the second lands 111 and 112 is a bow)
In covering 115, 116, 9 exactly each first land 1
11 and the width of the second land 112 and the width of the boats 115 and 116 are zero laps.

When the width of the land is larger than the width of the boat, it is called overlap, and when the width of the land is smaller than the width of the boat, it is called underlap.The actuator control performance is different for each type.
according to the characteristics you want to control.

As mentioned at the beginning of this specification, the current situation is that zero-wrap, overlap, and underlap products are used, but with the products of the present invention, the above-mentioned precise high-precision machining is completely unnecessary. There's no need.

It is extremely easy to work with, and as a result, reliability and controllability are improved compared to conventional ones.

In addition, the electric input value is alternately applied to each electric actuator 52.
By applying the power to the first group of 0,820 and the second group of 620,720, it is possible to perform the same control as a conventional servo valve. If you do not give the electrical input value to the second group at the same time when the electrical input value of Both underlapping and overlapping characteristics can be achieved in a valve depending on how the control electrical input values are applied.

Moreover, conventionally the first fluid outlet 103 is the supply source.

The second fluid outlet 104 has become necessary due to the displacement 9
In the case of the present invention, the supply amount (
In addition, it is possible to freely control the supply (or discharge) of the fluid to the second fluid outlet 6, and even change the magnitude of the electrical input value given to the first and second groups. First
Methods such as varying the flow rates of the fluid outlet 5 and the second fluid outlet 6 may also be used.

Also, 1st. Second. Third. Of course, it is also possible to use the fourth 2-port servo valve in such a way that the electric power values are given as different electric input values, and for this reason, it is wider than the conventional method, and the control possibilities are more detailed. , high-level control becomes possible.

This is especially true for compressible gases.

For example, the piston 3 of the actuator 380 is not necessarily a servo valve that exhausts the rear chamber 382 while supplying air to the front chamber 381 of the actuator 380 shown in FIG.
83 moves to the right, the gas in the rear chamber 382 is first removed and air is supplied to the front chamber 381, or the front chamber 381 is
In many cases, it is preferable for control purposes to vary the amount of gas exhausted by the rear chamber 382 in relation to the amount of air supplied to the rear chamber 382. Although this type of use was not possible with conventional servo valves, the present invention makes it possible to do so. achievable.

According to the present invention, the control performance is also good, which has not been possible in the past. It becomes possible to use a method of changing the function of the servo valve, for example from underlap to overlap I, during the operation of the fluid pressure actuator, contributing to more precise control of the fluid pressure actuator than before. I can do it.

In addition, high-precision machining is not required like conventional ones,
Therefore, the cost of 81 products is low and suitable for mass production.
Therefore, highly reliable products can be provided at low cost.

[Brief explanation of the drawing]

FIG. 1 is a cross-sectional view of one preferred embodiment of the present invention. FIG. 2 is a sectional view of a typical conventional one. FIG. 3 is a circuit diagram of the conventional one. FIG. 4 is a circuit diagram of one embodiment in which the present invention is used. FIG. 5 is a sectional view of an example of a two-port servo valve. FIG. 6 is a side sectional view of an example of a pilot type 2-port servo valve. next. 1 is a servo valve according to the present invention. 2 is the main body. 3 is the sub-base. 4 is a fluid inlet. 5 is a first fluid outlet. 6 is a second fluid outlet. 7.8 is a fluid outlet, and 9 is a drain hole. 11 is the first 2-port servo valve. 12 is the second 2-port servo valve. 13 is the third 2-port servo valve. 14 is the fourth 2-port servo valve. 20. 21 and 22 are through holes. 102 is a fluid inlet. 103 is the first ffi body exit. 104 is a second fluid outlet. 105 is a first fluid outlet. 10B is a second fluid outlet. 110 is the spool. 111 is the first land. 112 is the second land. 115.116 is a boat. 120 is an electric actuator. 130 is a spring. 301 is a servo valve. 350 is a fluid pressure actuator. 380 is an actuator. 381 is the front room. 382 is the rear chamber. 383 is a piston. 501 is a spool. 503 is the second land. 504 is the first land. 510 is a sleeve. 511 is a control port. 512 is the exit. 513, 514, 515 are O-rings. 520 is an electric actuator. 521 is the lower iron core. 522 is a case. 523 is the upper sleeve. 524 is the lower sleeve. 525 is a gap, 526 is a movable piece, 527 is a coil 6, and 52B is a top lid. 530 is the valve stem. 531 is a spring. 540 is a guide hole. 541 is a piston. 551 is a guide hole. 552 is the aperture part. 553 is the flapper valve seat. 554 is an inflow hole. 555 is a guide hole. 556 is the spool pressure chamber. 557 is an aperture needle. 560 is a spring. 561 is the flapper room. 604 is a first land, and 611 is a control port. 612 is the exit. 620 is an electric actuator, and 704 is the first land. 711 is a control port. 712 is the exit. ? 20 is an electric actuator. 804 is the first land. 811 is a control port. 812 is the exit. 820 is an electric actuator.

Claims (3)

[Claims] (1) First, second, third, and fourth units configured as one unit.
In the servo valve having a built-in 2-port servo valve, the fluid inlet of the servo valve is connected and communicated with the control ports of the first and second built-in 2-port servo valves, and an outlet of the servo valve communicates with a first fluid outlet of the servo valve and an outlet of a third built-in 2-port servo valve; a control port of the third 2-port servo valve communicates with a fluid outlet of the servo valve; The outlet of the built-in second 2-port servo valve communicates with the second fluid outlet of the servo valve and the outlet of the built-in fourth 2-port servo valve, and the control port of the fourth 2-port servo valve communicates with the servo valve's second fluid outlet and the outlet of the built-in fourth 2-port servo valve. A servo valve characterized in that it communicates with a fluid outlet of the valve. (2) The first, second, third, and fourth two-port servo valves are provided in each two-port servo valve,
2. The servovalve according to claim 1, wherein the servovalve is driven directly by an electric actuator. (3) The first, second, third, and fourth two-port servo valves are each driven by an indirect fluid amplification device controlled by an independently provided electric actuator. The servo valve according to item 1, characterized in that: