JPH01150001A - Servo mechanism - Google Patents

Abstract

PURPOSE:To improve the reliability of a servo system by connecting a fourth land provided for stability compensation to the spool of a servo valve. CONSTITUTION:A fourth land 50 is connected to a spool 14, while circular grooves 51, 52, formed on a casing 12, are communicated with a fifth port 54 and a sixth port 56 respectively. A seventh port 57, which is always communicated with a third chamber 55 and connected to a fourth port 33 through an intermediate passage 58 and a supply/discharge passage 40, is formed on the casing 12. When an external disturbance load is applied thereto and a minute displacement is generated on an output port, the displacement signal is fed-back to a servo valve 11 and the spool 14 is moved. The pressure rising side port out of the fifth and sixth ports 54, 56 is thus communicated with the seventh port 57, so that rapid change in the inner pressure is suppressed and stability is secured. The fourth land 50 can, even if it bites a foreign material or the like in, easily break it to improve the reliability of the servo system.

Description

[Detailed description of the invention] Ritate ■Dan beans! The present invention relates to a servomechanism with guaranteed stability.

For example, as a conventional servo mechanism for servo control, the one shown in FIG. 2 is known. This has a nozzle flap multi-pattern servo valve 1, and a spool 2 of the servo valve 1 is provided with three lands in sequence from one end to the other end. Further, 3 is an actuator that drives, for example, a movable wing of an aircraft, and the movement of a piston 4 of this actuator 3 is controlled by the servo valve 1. A stability compensation mechanism 5 is provided between the servo valve 1 and the actuator 3 to stabilize the servo system by suppressing load pressure changes inside the actuator 3. This stability compensation mechanism 5 includes a pressure differential piston 6 and a fixed It consists of a throttle 7 and a leakage valve 8. When the load pressure inside the actuator 3 suddenly changes, this pressure rise is detected by the pressure differentiating piston B and the fixed throttle 7, and the cage valve 8 is released to slightly divert the fluid from the high pressure side to the low pressure side. In order to improve stability, the

However, since such a conventional servo mechanism uses a leakage valve 8 that is opened and closed by minute fluid pressure in the stability compensation mechanism 5, foreign objects or the like may become lodged in the leakage valve 8. If the blockage occurs, there is a problem that the leakage valve 8 will be locked in this state. Furthermore, if air bubbles mixed in the fluid stay in the vicinity of the fixed throttle 7, the differential pressure changes, causing the stability compensation mechanism 5 to malfunction. Furthermore, since the pressure differential piston 6, leakage valve 8, and fixed throttle 7 as described above are required, there is also the problem that the structure becomes complicated and expensive.

1JI'I divination '・ This problem arises when the parts 1 are sequentially moved from one end to the other.
．． A spool of a servo valve is provided with second and third lands, and when the spool is located at a neutral position, the first land closes the spool, and when the spool moves toward one end, the spool opens and opens the first and third lands. a first port for supplying high-pressure fluid to a first chamber between two lands; a first port that is closed by a third land when the spool is in a neutral position and is opened when the spool moves toward the other end; 2. A second port that supplies high-pressure fluid to the second chamber between the third lands, a third port that constantly communicates with the first chamber and one chamber of the actuator, and a third port that constantly communicates with the second chamber and In the servo mechanism, the servo mechanism includes a fourth port communicating with the other chamber of the actuator, and a low pressure passage closed by the second land when the spool is in a neutral position, When a fourth land connected to the spool is provided, a third chamber is formed between the fourth land and the third land, and the third chamber is connected to the third port, and the spool is located at a neutral position. A fifth port is closed to the third land and is opened to communicate with the third chamber when the spool moves toward one end, and a fifth port is connected to the third port and connected to the fourth land when the spool is in the neutral position. By providing a sixth port that is closed and opens to communicate with the third chamber when the spool moves toward the other end, and a seventh port that is connected to the fourth port and constantly communicates with the third chamber. It can be solved.

Now, when a disturbance load that induces vibration is applied to the actuator output section and a slight displacement occurs in the output section, the displacement signal is fed back to the servo valve. By moving the spool in response to the feedback signal, the fifth and sixth ports
The pressure-increasing side port of the ports communicates with the seventh port, and as a result, the fluid in the actuator whose pressure has increased flows slightly into the low-pressure passage, thereby suppressing sudden changes in internal pressure and improving stability. will be compensated. Here, the fourth land used for stability compensation is connected to the spool of the servo valve that moves under the influence of a large fluid force, so even if a foreign object gets caught, it can be easily broken.
The reliability of the servo system can be improved. In addition, since this product compensates for stability without detecting differential pressure, even if bubbles in the fluid remain in the third chamber, stability is not affected at all, and reliability is also improved. can be improved. Furthermore, this product can ensure stability by simply connecting the fourth land to the spool and providing the fifth, sixth, and seventh ports, resulting in a simple structure and low manufacturing cost.

Fruit” 1 case Hereinafter, one embodiment of the present invention will be described based on the drawings.

In FIG. 1, 11 is a nozzle flapper type servo valve, and a spool 14 is housed in a spool chamber 13 formed in a casing 12 of the servo valve 11. This spool 14 is provided with first, second, and third lands 15, 16, and 17 in order from one end to the other end. A servo amplifier 18 amplifies the signal from the adder 18 and outputs it to the torque motor 20. The flapper 21 of the torque motor 20 is swung by the output signal from the servo amplifier 18 to move the spool 14. 2B
is a first port formed in the casing 12; this first port 26 is closed by the first land 15 when the spool 14 is in the neutral position;
4 moves toward one end, it is released and communicates with the first chamber 27 between the first and second lands 15 and 18. Further, 28 is a second port formed in the casing 12;
The port 28 is closed by the third land 17 when the spool 14 is located at the neutral position, and is opened when the spool 14 moves toward the other end to open the second and third lands 1B.
, 17 and communicates with the second chamber 29 between them. 3G is a high pressure passage whose one end is connected to a pump, and the other end of this high pressure passage 30 is bifurcated and connected to the first and second ports 26 and 28. As a result, the first port 2B or the second port
When the port 28 is opened, high pressure fluid flows into the first chamber 27 or the second chamber through the first port 2B or the second port 28.
It is supplied to chamber 29. Further, at this time, the second chamber 29 or the first chamber 27 on the side to which high-pressure fluid is not supplied communicates with a low-pressure passage 31 connected to the tank. 32 and 33 are third and fourth ports formed in the casing 12, the third port 32 is always in communication with the first chamber 27, while the fourth port 33 is always in communication with the second chamber 28. There is. 38 is an actuator whose piston rod 35 is connected to, for example, a movable wing of an aircraft; one chamber 37 of this actuator 38 communicates with a third port 32 via a supply/discharge passage 38; The fourth port 33 communicates with the chamber 39 via a supply/discharge passage 4o. The displacement of the piston rod 35 of the actuator 36 is detected by the displacement detector 4.
1, and the detection signal from the displacement detector 41 is sent to the adder 19 together with the setting signal. A fourth land 50 is provided in the spool chamber 13 on the other side of the third land 17, and this fourth land 50 is connected to the spool 14. Reference numerals 51 and 52 denote annular grooves formed in the casing 12, and one end of an intermediate passage 53 which is bifurcated into two is connected to these annular grooves 51 and 52, respectively. Further, the other end of this intermediate passage 53 is connected to the supply/discharge passage 38. The annular groove 51 has a constant ratio ll! in the circumferential direction. I
The fifth ports 54 connected to each other communicate with each other, and these fifth ports 54 are closed by the third land 17 when the spool 14 is in the neutral position, and are opened when the spool 14 moves toward one end. It communicates with a third chamber 55 formed between the third land 17 and the fourth land 50. Further, the annular groove 52 has a sixth port 5 equally proportioned in the circumferential direction.
These sixth ports 5B are closed by the fourth land 50 when the spool 14 is in the neutral position, and are opened when the spool 14 moves toward the other end to open the third chamber 55. It will be communicated to. In this way, the fifth port 5
4. The sixth port 56 is connected to the third port 32 via the intermediate passage 53 and the supply/discharge passage 38.

In addition, each port area of the fifth and sixth ports 54.58 is
The first and second ports are designed to reduce the amount of outflow from those ports.
, the third and fourth ports 2B, 28, 32, and 33. 57 is a seventh port formed in the casing 12, and this seventh port 57 is always in communication with the third chamber 55, and is connected to the fourth port 33 via the intermediate passage 58 and the supply/discharge passage 40. ing.

Next, the operation of one embodiment of the present invention will be explained.

Now, when a disturbance load that induces vibration is applied to the output portion of the actuator 3B and a slight displacement occurs in the piston rod 35, the displacement is fed back to the servo valve 11 via the adder 1θ and the servo amplifier 18. By this feedback signal, the spool 14 moves in the same direction as the moving direction of the piston rod 35, so that among the fifth port 54 and the sixth port 56, the port on the moving direction side of the spool 14, that is, the pressure increasing side port, This communicates with the seventh port 57, and as a result, the fluid in the actuator 36 whose pressure has increased slightly flows into the low pressure passage 31, thereby suppressing sudden changes in the internal pressure of the actuator 3B and ensuring stability. Here, even if the spool 14 catches a foreign object, the foreign object will be easily broken by the large fluid force, and even if air bubbles remain in the third chamber 55 etc., the stability will not be affected at all, so the servo System reliability is improved. Further, in this case, it is only necessary to add the fourth land 50 and the fifth, sixth, and seventh ports 54, 56, and 57 to the servo valve 11, so that the structure is simple and the manufacturing cost can be reduced.

In the above-mentioned embodiment, the spool 14 was moved by swinging the flapper 21, but in this invention, a force motor is directly connected to the spool 14, and this is controlled by the adder 19 signal and setting signal. The spool 14 may be moved by driving a force motor. Furthermore, in the present invention, the displacement and set displacement of the piston rod 35 of the actuator 36 are transmitted to the spool 14 by a link mechanism, thereby moving the spool 14. You can do it like this.

[lambda]J and circle] As explained above, according to the present invention, the reliability of the servo system is improved, and furthermore, the structure is simplified and the manufacturing cost can be reduced.

[Brief explanation of the drawing]

FIG. 1 is a schematic circuit diagram showing an embodiment of the present invention, and FIG. 2 is a schematic circuit diagram of a conventional servo mechanism. 11... Servo valve 14... Spool 15.
...1st land 16...2nd land 17...
3rd land 26...1st port 27...1st
Chamber 28...Second port 29...Second chamber
31...Low pressure passage 32...Third port 33
...Fourth port 36...Actuator 37...
・One chamber 39...Other chamber 5o...Fourth
Land 54...5th port 55...3rd chamber 56...
・6th port 57... 7th port patent applicant Teijin Seiki Co., Ltd. agent Patent attorney Ta 1) Toshio

Claims (1)

[Claims] A spool of a servo valve is provided with a first land, a second land, and a third land in order from one end to the other end, and when the spool is located at a neutral position, the spool is closed by the first land, and the spool is closed in one direction. When you move to the 1st, 2nd
a first port that supplies high pressure fluid to a first chamber between the lands;
A second land that is closed by a third land when the spool is in a neutral position, and is opened when the spool moves toward the other end to supply high-pressure fluid to a second chamber between the second and third lands. a third port that constantly communicates with the first chamber and one chamber of the actuator, a fourth port that constantly communicates with the second chamber and the other chamber of the actuator, and the spool is in a neutral position. a low pressure passage closed by a second land when the servo mechanism is located in the servo mechanism, a fourth land connected to the spool is provided on the other side of the third land, and
A third chamber is formed between the fourth land and the third land, and is connected to the third port, and when the spool is in the neutral position, it is closed to the third land and the spool is moved toward one end. A fifth port that opens when the spool moves and communicates with the third chamber, and a fifth port that is connected to the third port and is closed to the fourth land when the spool is in the neutral position and when the spool moves toward the other end. A servo mechanism comprising: a sixth port that is opened and communicates with the third chamber; and a seventh port that is connected to the fourth port and constantly communicates with the third chamber.