JP4734791B2 - Servo valve - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a servo valve used in an aircraft, a ship, a vehicle, a general industrial machine, and the like, and more particularly, to a servo valve effective for controlling a flow rate of hydraulic fluid of an actuator.
[0002]
[Prior art]
There are various types of servo valves used for controlling the flow rate of hydraulic fluid for actuators of aircraft, ships, vehicles, general industrial machines, etc. For example, a nozzle flapper type servo valve as shown in FIG. 3 is generally known. ing.
[0003]
That is, the servo valve 31 includes a torque motor unit 32 that converts an input current into a displacement of the flapper 38 via the armature 34, and a pair of nozzles 39, 39 provided to oppose the displacement of the flapper 38 across the flapper 38. The hydraulic pressure amplifying unit 36 that converts the pressure difference of the hydraulic pressure via the pressure difference between the hydraulic pressure amplifying unit 36, the valve portion 42 that controls the flow rate of the hydraulic oil, and the displacement of the piston 45 A feedback unit 52 that feeds back to the flapper 38 is provided.
[0004]
When a current is input to the torque motor unit 32 of the servo valve 31 configured as described above, a torque corresponding to the input current is generated in the torque motor unit 32 and the armature 34 rotates to follow the rotation of the armature 34. Accordingly, the flapper 38 swings and displaces in the direction of the nozzle 39, and a difference occurs in the back pressure between the nozzles 39 and 39 according to the displacement of the flapper 38. Here, since the back pressure of both nozzles 39 and 39 is a pressure acting on both end faces of the piston 45, the piston 45 moves and displaces according to the difference in back pressure between the nozzles 39 and 39. When the piston 45 is displaced, the feedback wire 53 of the feedback section 52 bends following the displacement of the piston 45, and the flapper 38 is pushed back to the center by returning from the bent state of the feedback wire 53 to the original state. The difference between the back pressures of the nozzles 39 and 39 becomes 0, the piston 45 stops at that position, and the flow rate of the hydraulic oil through the valve portion 42 is determined.
[0005]
[Problems to be solved by the invention]
However, in the servo valve 31 configured as described above, a plurality of servo valves 31 and 31 may be used in parallel when controlling the flow rate of a large volume of hydraulic oil. Since the characteristics of the valves 31 are different, the operation becomes unstable, the servo valves 31 and 31 cannot be completely synchronized, and desired flow rate control cannot be performed. In order to solve such a problem, a method has been proposed in which a plurality of servo valves 31 and 31 are connected and synchronized by a mechanical link mechanism (not shown). However, the mechanical link mechanism has a complicated structure. This complicates the structure of the servo valve as a whole and increases the price.
[0006]
The present invention solves the above-described problems. When a plurality of servo valves are used in parallel, the plurality of servo valves are not affected by the difference in characteristics of the individual servo valves. An object of the present invention is to provide a servo valve that can be completely synchronized, that can simplify the entire structure, and that can keep the price low.
[0007]
[Means for Solving the Problems]
In order to solve the above-described problems, the present invention provides a body with a torque motor unit that converts an input current into a displacement of a flapper via an armature, and a pair of displacements of the flapper that are opposed to each other with the flapper interposed therebetween. A hydraulic pressure amplifying part for converting the pressure difference of the hydraulic pressure through a nozzle, a valve part for converting the pressure difference of the hydraulic pressure amplifying part into a displacement of the piston and controlling the flow rate of hydraulic oil, and the displacement of the piston to the flapper; In a servo valve provided with a feedback section for feedback, the valve section is divided into two valves, one valve half connected to the one nozzle and the other valve half connected to the other nozzle. A synchronizing plate which is divided into two groups and is provided in parallel with at least two sets, and one valve half and the other valve half of each set are displaced integrally with the armature. It is obtained by employing the means arranged to synchronize by constantly abut.
In this case, for example, a support shaft is rotatably attached to the body via a bearing, one end of the support shaft is integrally connected to the armature, the other end is integrally connected to the body, and The synchronization plate and the flapper may be coupled to the support shaft so as to swing following the rotation of the support shaft.
Further, the support shaft may be constituted by a torsion spring and may also be used as the feedback unit.
[0008]
According to the present invention, when the current is input to the torque motor unit by employing the above-described means, a torque corresponding to the input current is generated to displace the armature, and the flapper and the synchronization plate are integrated with the armature displacement. Is displaced, the distance between the flapper and both nozzles changes, and a difference occurs in the back pressure of both nozzles, and this difference in back pressure causes the piston of one valve half or the other valve half of each pair to move. It moves and displaces, and the flow rate of hydraulic oil is controlled. In this case, one valve half and the other valve half of each set are always in contact with the synchronization plate, and thus operate in synchronization.
In addition, when the support shaft is composed of a torsion spring and is also used as a feedback unit, the support shaft is twisted when the support shaft rotates integrally with the armature, and the support shaft is changed from the twisted state to the original state. By returning, the flapper is pushed back to the neutral position, and the displacement of the piston in each valve half is fed back to the flapper.
[0009]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention shown in the drawings will be described.
FIG. 1 shows an embodiment of a servo valve according to the present invention. The servo valve 1 includes a torque motor unit 2, a hydraulic amplifier unit 12, a valve unit 18, a feedback unit 31, and a body 9. It has.
[0010]
The torque motor unit 2 converts an input current into a displacement of the flapper 14, and a permanent magnet 3 having a magnetic pole facing the tip and an armature 4 provided rotatably between both magnetic poles of three permanent magnets. The coil 5 wound around the armature 4, one end connected to the armature 4, the other end fixed to the body 9, and the support shaft 6 rotatable to the body 9. It comprises a bearing 7 such as a radial bearing to be supported, and a seal member 8 such as an O-ring for sealing between the support shaft 6 and the body 9.
[0011]
The hydraulic amplifying unit 12 converts the displacement of the armature 4 of the torque motor unit 2 into a hydraulic pressure difference via the flapper 14 and is connected to the support shaft 6 of the torque motor unit 2 so as to be orthogonal to the axis. The nozzle flapper mechanism 13 includes a flapper 14 that swings following the support shaft 6 and a pair of nozzles 15 and 15 that are provided to face each other across the flapper 14.
[0012]
Two synchronization plates 10 and 11 are connected to the support shaft 6 of the torque motor unit 2 in a cross shape so as to be orthogonal to the axis of the support shaft 6, and swing according to the rotation of the support shaft 6. Yes. One synchronizing plate 10 is always in contact with one valve half 19 of a valve portion 18 to be described later, and the other synchronizing plate 11 is always in contact with the other valve half 25.
[0013]
The hydraulic oil is introduced into each nozzle 15 through a main filter 17 and an orifice 16. One nozzle 15 communicates with a rear end portion of a cylinder chamber 21 of one valve half 19 of a valve portion 18 described later, and the other nozzle 15 communicates with a rear end portion of a cylinder chamber 27 of the other valve half 25. It has come to be. Accordingly, the back pressure acting on each nozzle 15 is guided to the rear end portions of the cylinder chambers 21 and 27 of the valve half portions 19 and 25, that is, the rear end surfaces of the pistons 22 and 28.
[0014]
When the input current to the torque motor unit 2 is 0, the flapper 14 is located at an equal distance from both nozzles 15 and 15, and the same amount and pressure of hydraulic oil is ejected from both nozzles 15 and 15. The back pressures of both nozzles 15 and 15 are in a balanced state. On the other hand, when the current is input to the torque motor unit 2 and the armature 4 rotates, the support shaft 6 rotates integrally with the armature 4, and the flapper 14 and the synchronization plates 10 and 11 follow the rotation of the support shaft 6. The flapper 14 is displaced in the direction of the nozzle 15. When the flapper 14 is displaced in the direction of the nozzle 15, the distance between the flapper 14 and both the nozzles 15, 15 changes, the back pressure balance of both the nozzles 15, 15 is lost, and the back pressure of both nozzles 15, 15 changes. A difference occurs in the pressure of the hydraulic oil guided from the nozzles 15 and 15 to the rear end surfaces of the pistons 22 and 28, and the pistons 22 and 28 move and are displaced according to the pressure difference.
[0015]
The valve portion 18 is composed of one valve half portion 19 and the other valve half portion 25. The two valve half portions 19 and 25 are set as one set, and two sets of these are formed in parallel. 9 is provided.
[0016]
One valve half 19 is provided with a cylinder chamber 21 therein, and is provided with a supply port (not shown), a return port (not shown), and a control port (not shown) communicating with the cylinder chamber 21. The body 20, a piston 22 provided movably in the cylinder chamber 21 of the body 20, a spring 24 provided between the rear end surface of the cylinder chamber 21 and the rear end surface of the piston 22, and a front end portion of the piston 22 are integrated. And a plunger 23 protruding from the cylinder chamber 21.
[0017]
The other valve half 25 is provided with a cylinder chamber 27 inside, and is provided with a supply port (not shown), a return port (not shown), and a control port (not shown) communicating with the cylinder chamber 27. The body 26, a piston 28 provided movably in the cylinder chamber 27 of the body 26, a spring 30 provided between the rear end surface of the cylinder chamber 27 and the rear end surface of the piston 28, and a front end portion of the piston 28 are integrated. And a plunger 29 protruding from the cylinder chamber 27.
[0018]
The back pressure of one nozzle 15 of the hydraulic amplifying unit 12 is guided to the rear end of the cylinder chamber 21 of one valve half 19 of each valve unit 18, and the rear end of the cylinder chamber 27 of the other valve half 25. The back pressure of the other nozzle 15 of the hydraulic amplifying unit 12 is guided to the part, and the piston 22 of one valve half 19 or the piston of the other valve half 25 is selected according to the back pressure difference between the two nozzles 15 and 15. 28 moves in the cylinder chambers 21 and 27 and is displaced. Then, each port is opened / closed or the degree of opening / closing of each port is adjusted according to the displacement of the pistons 22, 28, and the flow rate of hydraulic oil through each port is controlled.
[0019]
The feedback portion 31 is also used as a support shaft 6 made of a torsion spring. When the support shaft 6 rotates integrally with the rotation of the armature 4, the support shaft 6 is twisted, and the support shaft 6 is By returning from the twisted state to the original state, the flapper 14 is pushed back to the neutral position, the pistons 22 and 28 are stopped at that position, and the flow rate of the hydraulic oil through the pistons 22 and 28 is determined. That is, the support shaft 6 has a function of feeding back the displacement of the pistons 22 and 28 to the flapper 14.
[0020]
When a current is input to the torque motor unit 2 of the servo valve 1 configured as described above, a torque proportional to the input current is generated in the torque motor unit 2, and the armature 4 rotates according to the torque.
[0021]
When the armature 4 is rotated, the support shaft 6 is rotated integrally with the rotation of the armature 4, and the support shaft 6 is twisted, and the flapper 14 and the synchronization plates 10 and 11 are swung following the rotation of the support shaft 6. The flapper 14 is displaced in the direction of the nozzle 15, and the distance between the flapper 14 and both nozzles 15, 15 located at the same distance from both nozzles 15, 15 is changed, so that both nozzles are kept in balance. There is a difference in the back pressure of 15 and 15. Since this back pressure is a pressure acting on the rear end surfaces of the pistons 22 and 28, the pistons 22 and 28 start to move toward lower pressures. In this case, one synchronization plate 10 is always in contact with the plunger 23 of one valve half 19 of each valve portion 18, and the other synchronization plate 11 is always in contact with the plunger 29 of the other valve half 25. Therefore, one valve half 19 and the other valve half 25 of both valve portions 18 and 18 operate synchronously.
[0022]
When the support shaft 6 returns from the twisted state to the original state, the flapper 14 is pushed back to the neutral position, the difference in back pressure between the nozzles 15 and 15 becomes zero, and the pistons 22 and 28 stop at that position. Thus, the flow rate of the hydraulic oil through the valve unit 18 is determined.
[0023]
In the servo valve 1 according to this embodiment configured as described above, one valve half 19 and the other valve half of both valve portions 18, 18 are provided by synchronization plates 10, 11 provided on the support shaft 6. 25 can be operated in synchronism, so that even if there is a difference in characteristics between the individual valve halves 19, 25, the operation does not become unstable. It will be perfectly synchronized within the error range. Therefore, when both the valve portions 18 and 18 are connected to an actuator (not shown), the valve portions 18 and 18 can be operated in a mechanically completely synchronized manner without requiring a mechanical link mechanism. Further, when the polarities of both valve portions 18 and 18 are changed and connected to the actuators, the phase of the speed can be completely shifted by 180 °, which is effective for changing the reciprocating motion to a rotational motion or the like.
[0024]
【The invention's effect】
In the present invention, the valve portion is divided into two parts, that is, one valve half connected to one nozzle and the other valve half connected to the other nozzle. Even if there is a difference in the characteristics of the individual valve halves, one valve half and the other valve half of each set are always in contact with the synchronizing plate that is displaced integrally with the armature. The operation does not become unstable, and the plurality of valve portions can be operated in complete synchronization. That is, even when a plurality of valve portions are connected to, for example, an actuator, the valve portions can be operated in a mechanically completely synchronized manner. Therefore, a complicated and expensive mechanical link mechanism becomes unnecessary, the structure of the entire servo valve can be simplified, and the price can be reduced. Furthermore, when the polarities of a plurality of valve portions are changed and connected to actuators, the speed phase can be easily shifted by 180 °, which is effective for changing the reciprocating motion to a rotational motion or the like.
In addition, the support shaft is rotatably attached to the body via a bearing, and a seal member is used to seal the space between the support shaft and the body, so that a commercially available inexpensive radial bearing can be used for the bearing. A commercially available inexpensive O-ring or the like can be used for the seal member. Therefore, the overall price can be kept low, and an inexpensive servo valve can be provided.
In addition, since the support shaft is composed of a torsion spring and is also used as a feedback unit, a feedback unit that feeds back the displacement of the piston to the flapper can be configured by a support shaft made of an inexpensive torsion spring. The price of can be kept cheap.
[Brief description of the drawings]
FIG. 1 is a schematic view showing an embodiment of a servo valve according to the present invention.
FIG. 2 is a schematic view showing an example of a conventional servo valve.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 ... Servo valve 2 ... Torque motor part 3 ... Permanent magnet 4 ... Armature 5 ... Coil 6 ... Support shaft 7 ... Bearing 8 ... Seal member 9 ... Body 10, 11 ... Synchronizing plate 12 ... Hydraulic amplifier 13 ... Nozzle flapper mechanism 14 ... Flapper 15 ... Nozzle 16 ... Orifice 18 ... Valve part 19 ... One valve half part 20, 26 ... Body 21, 27 ... Cylinder chamber 22, 28 ... Piston 23, 29 ... Plunger 24, 30 ... Spring 25 ... The other valve half part Part 31 ... Feedback part

Claims (3)

Oil pressure amplification that converts the input current into the displacement of the flapper via the armature on the body, and the displacement of the flapper via a pair of nozzles provided facing each other across the flapper A servo valve comprising: a valve portion that converts a pressure difference between the hydraulic pressure amplifying portion and a displacement of the piston to control a flow rate of hydraulic oil; and a feedback portion that feeds back the displacement of the piston to the flapper.
The valve part is divided into two parts, one valve half part connected to the pair of nozzles and the other valve half part connected to the other nozzle. In parallel,
A servo valve characterized in that one valve half and the other valve half of each set are always brought into contact with and synchronized with a synchronizing plate that is displaced integrally with the armature. Is attached rotatably to the support shaft via a bearing to the body, one end of the support shaft and integrally connected to the armature, coupled before Symbol synchronization plate and the flapper and the other end, the support shaft 2. The servo valve according to claim 1, wherein the synchronizing plate and the flapper are made to swing following the rotation of the servo valve.   3. The servo valve according to claim 2, wherein the support shaft is constituted by a torsion spring and is also used as the feedback unit.

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