JP2824236B2 - Direct drive type hydraulic servo valve - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a direct drive valve (abbreviated name) used in general industrial hydraulic systems and aircraft hydraulic systems to control the direction and flow rate of hydraulic oil and to directly drive a spool by an electric motor. DDV).

[0002]

2. Description of the Related Art In the field of hydraulics, servo control of a spool valve for controlling the direction and flow rate of hydraulic oil is performed by a so-called electric hydraulic servo valve (abbreviated as EHSV; Electric Hydraulic Servo Valve) for both general industrial use and aircraft use.
Or, the abbreviation EHV (Electric Hydraulic Valve) has been mainly used, but recently, (1) the structure is simple, (2) the failure is small and the reliability is high due to the strong resistance to foreign matter being caught, (3) The development of electronic technology has made it possible to reduce the size and capacity of electrical systems.
For example, direct drive hydraulic servo valves have been actively adopted. In the field of aircraft, this direct-drive hydraulic servo valve is used in place of a mechanical control system such as a rod or a cable in place of a mechanical control system such as a rod or a cable from a pilot control device, for example, in the case of a helicopter rotor. To the control surface with wires,
It has become an indispensable technology for a fly-by-wire (FBW) steering system that controls the control surface only by electric signals, and is mainly used for fixed-wing aircraft.

[0003]

In such prior art, a mechanical spring is used in the electro-hydraulic servo valve to return the spool to the neutral position. Is difficult to provide redundancy for failures, and for aircraft that require high reliability,
This is one factor that suppresses high reliability. In addition, the mechanical spring has a problem in that it has a limitation in improving the responsiveness, which hinders high responsiveness. Further, in the above-described electro-hydraulic servo valve, although the oil passage formed by the spool and the sleeve changes the opening degree in accordance with the displacement of the spool, the oil amount of the operating oil to various actuators is controlled. When the degree becomes small, if the foreign matter is caught, the spool cannot be smoothly displaced, and there is a problem that the actuator cannot be operated.

An object of the present invention is to provide a direct-drive type hydraulic servo valve capable of improving responsiveness and reliability without increasing the size of the configuration.

[0005]

According to a first aspect of the present invention, there is provided a power supply for rotating an output shaft from a neutral position within a predetermined angle range by energizing and returning the output shaft to the neutral position by magnetic reluctance torque. Motor, an outer sleeve in which a first passage for guiding hydraulic oil is formed, and a second passage formed in the outer sleeve so as to be displaceable in the axial direction thereof and communicating with the first passage for guiding hydraulic oil. The inner sleeve is housed in the inner sleeve so as to be displaceable in its axial direction,
A spool in which a third passage communicating with the second passage and guiding hydraulic oil is formed; and the outer sleeve, the inner sleeve, and the spool are coaxially housed so as to be displaceable in a common axial direction. A housing having a plurality of ports communicating with one passage for guiding hydraulic oil, and a member inserted in the one-diameter line direction into the other end in the axial direction of the inner sleeve opposite to the one end in the axial direction near the output shaft. A retaining pin, a pressing ring mounted on the inner sleeve, and a step ring formed on the inner sleeve and a pressing ring abutting on the other axial end of the outer sleeve opposite to the one axial end near the output shaft; And a pressing ring interposed between the pressing ring and the housing and supported by the other axial end of the outer sleeve and the stepped surface of the inner sleeve. A first spring for resiliently pressing the a direct-drive hydraulic servo valve which comprises a second spring interposed between the pressing ring and the spring receiving piece. According to the present invention, the output shaft is moved from the neutral position to a predetermined angle range, for example, ±
Rotate in the angle range of 20-30 ° to displace the spool. When the power is cut off, the output shaft returns to the neutral position by the magnetic reluctance torque. Such a restoring force to the neutral position by the magnetic reluctance torque can be realized by a magnetic circuit of the magnetic flux of the permanent magnet. In this way, the output shaft of the motor is statically and stably returned to the neutral position without using a mechanical spring, so a lightweight and highly reliable hydraulic servo valve is realized without increasing the size of the structure. can do. The spool directly driven by the motor has a third passage, is housed in the inner sleeve,
The degree of opening of the third passage with respect to the second passage can be changed by rotation of the output shaft of the motor. The inner sleeve is housed in the outer sleeve, and the second passage communicates with the first passage. The outer sleeve is housed coaxially in the housing together with the inner sleeve and the spool and is displaceable in a common axial direction. The housing is displaced in the same direction together with the spool when foreign matter is caught between the pressure port to which hydraulic oil is supplied from the pump, the tank port connected to the tank, and the second and third passages connected to the actuator. However, the displacement of the spool is prevented from being hindered by foreign matter. As a result, loss of the function of the valve due to foreign matter being caught is prevented, and reliability is improved.

According to a second aspect of the present invention, an operation detector for detecting rotation of the output shaft of the motor or displacement of the spool is provided, and the motor is feedback-controlled by a detection signal. According to the present invention, the hydraulic servo valve is provided with an operation detector. The operation detector may detect rotation of the output shaft of the motor, or may detect displacement of the spool. With such an operation detector, it is possible to control the supply amount and the supply direction of the hydraulic oil to the actuator, and thus to control the actuator with high accuracy.

According to a third aspect of the present invention, there is provided a pressure sensor for detecting a pressure in the first passage. According to the present invention, the pressure in the first passage is detected by the pressure detector. By providing such a pressure detector, when the hydraulic servo valve according to claim 1 or 2 adopts a multi-system control valve called a so-called jam proof valve, it detects that foreign matter has caught in the valve, It is possible to notify the abnormality. This makes it possible to control the actuator with higher reliability.

[0008]

FIG. 1 is a sectional view showing a direct-drive hydraulic servo valve 1 according to an embodiment of the present invention. Direct-drive hydraulic servo valve (abbreviated DDV,
Basically, the hydraulic servo valve 1) rotates the output shaft 2 eccentric from the center of the rotation axis by energization within a predetermined angle range from the neutral position, and magnetically rotates the output shaft 2 in the neutral position. A torque motor 3 having a force to return to
And a valve body 4 directly driven by the torque motor 3. This hydraulic servo valve 1 is, for example, in a helicopter requiring high responsiveness and reliability, a fly-by-wire (FBW) control system for controlling a control surface by connecting a wire from a pilot control device to a rotor with an electric wire. The valve body 4 is used as a servo control valve for the parallel actuators Cy1 and Cy2, and includes first and second blocks 5 corresponding to the actuators Cy1 and Cy2.
a and 5b.

The valve body 4 has a torque motor 3 mounted substantially at the center thereof and two housings 6a and 6a connected to each other.
6b, outer sleeves 7a and 7b housed in the housings 6a and 6b, inner sleeves 8a and 8b housed in the outer sleeves 7a and 7b, and inner sleeves 8a and 8b.
8b. The outer sleeves 7a, 7b, the inner sleeves 8a, 8b and the spools 9a, 9b are coaxial, and
a and 6b are mutually displaceable in a common axial direction.

Each of the housings 6a and 6b has a pressure port P to which hydraulic oil is supplied from a pump (not shown), a tank port R connected to a tank (not shown), and flow ports 11a and P1b connected to respective ports P1a and P1b of one actuator Cy1.
It has two ports A and B connected to each other via 11b. Each outer sleeve 7a, 7b is connected to each port P, R,
First passages 12a and 12b communicating with A and B to guide hydraulic oil
And each inner sleeve 8a, 8b has a first passage 12a, 1
2b, and has second passages 13a, 13b for guiding the hydraulic oil, and each spool 9a, 9b is connected to the second passage 13a, 13b.
And third passages 14a and 14b for communicating the hydraulic oil with the third passage.

The outer sleeve 7a of the first block 5a has one end in the axial direction near the output shaft 2 connected to the second block 5b.
The outer sleeve 7b is fitted on one end in the axial direction near the output shaft 2 and is arranged so as to form the same axis. Each outer sleeve 7
a, 7b are connected to the pressing rings 16a, 16b.
b, and each pressing ring 16a, 16b has a first spring 17 whose one end is supported by the housing 6a, 6b.
a, 17b, the inner sleeve 8
a, 8b. Each of the inner sleeves 8a, 8b has one end in the axial direction near the output shaft 2 spaced apart from each other, and the other end in the axial direction has a locking pin 18a, 18b inserted in the diameter direction. Spring receiving piece 2 locked by
0a and 20b are mounted, and one ends of the second springs 19a and 19b are supported. The other ends of the second springs 19a, 19b abut against the pressing rings 16a, 16b supporting the step surfaces 21a, 21b of the inner sleeves 8a, 8b, and resiliently press the inner sleeves 8a, 8b. The first and second springs 17a, 17b; 19a, 19b are realized by compression coil springs.

As described above, the locking pins 18a, 18b are inserted through the other ends of the inner sleeves 8a, 8b in the axial direction in the diameter direction, and the pressing rings 16a, 16b are connected to the inner sleeves 8a, 8b.
a, 8b, and the step surfaces 21a, 21b and the outer sleeves 7a, 7b absorbed by the inner sleeves 8a, 8b.
Abut on the other end in the axial direction of each of the inner sleeves 8a, 8b.
Locking pins 18a, 18b and pressing rings 16a, 1
6b, spring receiving pieces 20a and 20b are mounted respectively, and further, each pressing ring 16a and 16b and the housing 6
a and 6b, and the second springs 19a and 19b are interposed between the pressing rings 16a and 16b and the spring receiving pieces 20a and 20b, respectively. In the first block 5a, the second passage 13a of the inner sleeve 8a and the spool 9a
When jamming occurs due to a foreign object being caught between the third sleeve 14a and the third passage 14a, if the spool 9a is moving rightward in FIG. 1, the inner sleeve 8a is opposed to the spring force of the second spring 19a.
Can be displaced in the same direction as the spool 9a, and if the spool 9a is moving to the left in FIG. 1, it can be displaced in the same direction as the spool 9a against the spring force of the first spring 17a. it can. Therefore, it is possible to prevent the rotation of the output shaft 2 of the torque motor 3 from being hindered by the jamming, and to prevent an uncontrollable failure state due to the intrusion of foreign matter. This is the same in the second block 5b.

The spool 9a on the first block 5a side
A third spring 22 composed of a compression coil spring is interposed between the output shaft 2 and the spools 9a and 9b.
The occurrence of backlash between them is prevented.

The housing 6b of the second block 5b has
A linear sensor (abbreviated as LVDT; Linear VariableDiffe) which is an operation detector for detecting displacement of each of the spools 9a and 9b.
rential Transformer) S1 is provided. The displacement detection signals of the spools 9a and 9b output from the linear sensor S1 are input to the servo control means 15, and the rotation amount of the output shaft 2 of the torque motor 3 is controlled by the motor drive current from the servo control means 15. Is done. As a result, the spools 9a and 9b are simultaneously displaced, and the third passage 1
The opening amounts of the first and second actuators Cy1, C2 are controlled by controlling the opening amounts of the first and second actuators Cy1, C4.
The operation of each piston rod 24a, 24b of y2 is controlled. The piston rods 24a and 24b are connected to each other, and the displacement thereof is a linear sensor S similar to the linear sensor S1.
3 is detected. This detection signal is input to the servo control means 15, and the operation delay of the torque motor 3 due to disturbance or the like is compensated by feedback control.

Instead of the linear sensor S1, a rotary sensor (abbreviated as RVDT; Rotary Variable Differential) for detecting the rotation of the output shaft 2 of the torque motor 3 and therefore the rotation of the rotor 25 as shown by the phantom line in FIG.
Transformer) S2 may be provided.

Each of the housings 6a and 6b is also provided with a pressure detection port 26a, 26b. The first passages 12a, 12b are formed through the pressure detection ports 26a, 26b.
Hydraulic oil inside is guided to pressure detectors S4a and S4b. Each of the pressure detectors S4a and S4b is realized by a pressure switch or a pressure sensor, and detects the entry of foreign matter into the valve.

FIG. 2 is an enlarged sectional view of the torque motor 3 taken along the line II-II in FIG. Torque motor 3
In a casing 31, there are provided three layers of electromagnetic coils 34a, 34b, 34c in which windings 33a, 33b are toroidally wound around a ring-shaped yoke 32 made of a magnetic material in an axial direction perpendicular to the plane of FIG. Stacked, each electromagnetic coil 34a ~
The two poles 35a, 3 are provided on the inner peripheral surface of the pair of poles 35a, 3 at 90 ° positions in the circumferential direction between the windings 33a, 33b.
5b is fixed. Each of the poles 35a and 35b is made of a magnetic material, and is spaced apart from each other with two slits 36a and 36b in axial symmetry.

A substantially cylindrical rotor 25 to which the output shaft 2 is fixed is housed at one end in the axial direction between the poles 35a and 35b. Both ends of the rotor 25 in the axial direction are ball bearings 37a. , 37b. The rotor 25 is provided with a permanent magnet 39 having both ends in the one diameter direction in the rotor casing 38 in the cross section perpendicular to the axis shown in FIG.
Each of the electromagnetic coils 34a to 34c has two bolts 40a,
A lid 42 is fixed to the end plate 41 by a bolt 43 in a liquid-tight manner by a bolt 43.

Each winding 33 is controlled by the servo control means 15.
a, 33b are energized, and dashed arrows 48a, 48b
A magnetic field is generated as shown by, and the rotor 25 rotates from the neutral position shown in FIG. 2 around the rotation axis 47 in the direction of the arrow D1 or the direction of the arrow D2 within a predetermined angle range. When the energization of each of the windings 33a and 33b is interrupted, the permanent magnet 39
As a result, a magnetic field is generated as shown by solid arrows 49a and 49b, and the rotor 25 magnetically returns from the rotational position at the predetermined angle to the initial position shown in FIG. Such a restoring force of the rotor 25 is based on magnetic reluctance torque.

FIG. 3 is a simplified perspective view showing a connection structure between the spool 9a and the output shaft 2, and FIG. 4 is a sectional view taken along the line IV-IV of FIG. The distal end 2a of the output shaft 2 is formed in a substantially spherical shape, fits into a shaft hole 50 formed at one axial end of the spool 9a, and slides on the inner peripheral surface. The axis 51 of the output shaft 2 is eccentric from the rotation axis 47 of the rotor 25 by a distance ΔL.
Is perpendicular to the axis 52 of the spool 9a, and the rotation of the output shaft 2 is canceled by the rotation of the spool 9a about the axis 52 in the direction of the arrow 53. In the configuration shown in FIG. 1, one end of the spool 9b of the second block 5b in the axial direction is fitted to one end of the spool 9a of the first block 5a in the axial direction, and is connected to each other.
The distal end portion 2a of the output shaft 2 is fitted into a shaft hole 50 formed at one end of the spool 9b in the axial direction.
The torque motor 3 and the spools 9a and 9b are connected in a rotary / linear combination manner.

FIG. 5 is a simplified perspective view showing a connection structure between the spool 9a and the output shaft 2 according to another embodiment of the present invention, and FIG. 6 is viewed from a section line VI-VI in FIG. It is sectional drawing. In the present embodiment, the spool 9a includes a hollow spool body 55 and a spool shaft 56 fixed to the other axial end of the spool body 55 and protruding from one axial end.
And the spool shaft 56 is separated from the spool body 55 with a gap. A bush 57 is fitted to the tip of the spool shaft 56, and the vicinity of the tip 2 a of the output shaft 2 is inserted into the bush 57. With such a configuration, the eccentricity of the output shaft 2 with respect to the rotation axis 47 of the rotor 25 can be absorbed by the deflection of the spool shaft 56.

FIG. 7 is a simplified perspective view showing a connection structure between the spool 9a and the output shaft 2 according to still another embodiment of the present invention, and FIG. 8 is a sectional view taken along line VIII-VIII of FIG.
It is sectional drawing seen from. In this embodiment, a fitting hole 61 having a spherical inner peripheral surface is formed at one axial end of the spool 9a, and a bush 62 having a spherical outer peripheral surface is fitted into the fitting hole 61. The bush 62 has the output shaft 2
The vicinity of the tip 2a is inserted. The rotation center 63 in the fitting hole 61 of the bush 62 is aligned with the axis 5 of the spool 9a.
2, the eccentricity of the output shaft 2 causes the spool 9a to move around its axis 52 with an arrow 64.
It can be tolerated by rotating in the direction.

[0023]

As still another embodiment of the present invention, as shown in FIG. 9, a spool 68 having a land having a uniform width b in the circumferential direction is axially displaced by a force motor 69. Is also good. When implementing such a configuration as a jam-proof valve, the spool 6
8 may be connected coaxially in series. Spool 68 of this embodiment
Is the output force Fm of the force motor 69, Fs = Fm.

[0025]

According to the present invention, since the output shaft of the motor has a force to return to the neutral position without using a mechanical spring, it is lightweight without increasing the size of the structure. A highly reliable hydraulic servo valve can be realized. Also, even when jamming occurs due to foreign matter being caught between the second passage and the third passage, the inner sleeve is displaced in the same direction as the spool moving direction, and the rotation of the output shaft is hindered by the jamming. This prevents loss of function of the valve and increases reliability.

According to the present invention, the displacement of the spool or the rotation of the output shaft of the motor is detected by the operation detector to control the supply amount and the supply direction of the hydraulic oil to the actuator with high accuracy. be able to.

According to the third aspect of the present invention, since the pressure in the first passage is detected by the pressure detector, the occurrence of jamming can be detected using the detection output from the pressure detector. By applying such a pressure detector to a multi-system control valve such as a jam proof valve, a more reliable valve can be configured.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view showing a direct-drive hydraulic servo valve 1 according to an embodiment of the present invention.

FIG. 2 is an enlarged cross-sectional view of the torque motor 3 taken along the line II-II in FIG.

FIG. 3 is a simplified perspective view showing a connection structure between a spool 9a and an output shaft 2.

FIG. 4 is a cross-sectional view taken along the line IV-IV of FIG. 3;

FIG. 5 is a simplified perspective view showing a connection structure between a spool 9a and an output shaft 2 according to another embodiment of the present invention.

FIG. 6 is a sectional view taken along section line VI-VI in FIG. 5;

FIG. 7 shows a spool 9a according to still another embodiment of the present invention.
FIG. 2 is a simplified perspective view showing a connection structure between a motor and an output shaft.

FIG. 8 is a sectional view taken along section line VIII-VIII in FIG. 7;

FIG. 9 shows a spool 68 according to still another embodiment of the present invention.
FIG. 4 is a perspective view showing a force motor and a force motor.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Direct drive type hydraulic servo valve 2 Output shaft 3, 3a, 3b Torque motor 4 Valve body 6a, 6b Housing 7a, 7b Outer sleeve 8a, 8b Inner sleeve 9a, 9b; 68 Spool 12a, 12b First passage 13a, 13b No. 2 path 14a, 14b 3rd path 15 Servo control means 16a, 16b Press ring 17a, 17b First spring 18a, 18b Lock pin 19a, 19b Second spring 20a, 20b Spring receiving piece 21a, 21b Step surface S1, S3 Linear Sensor S2 Rotary sensor S4a, S4b Pressure detector

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int.Cl. ⁶ , DB name) F15B 13/044 F16K 11/00-11/24

Claims (3)

(57) [Claims] 1. A motor having a power for rotating an output shaft from a neutral position within a predetermined angle range by energization and returning the output shaft to the neutral position by magnetic reluctance torque, and a first passage for guiding hydraulic oil is formed. An outer sleeve to be displaced in the axial direction in the outer sleeve;
An inner sleeve in which a second passage communicating with the passage and guiding the hydraulic oil is formed; and an inner sleeve displaceably accommodated in the inner sleeve in the axial direction.
A spool in which a third passage communicating with the passage and guiding hydraulic oil is formed; and the outer sleeve, the inner sleeve, and the spool are housed coaxially and displaceably in a common axial direction, and a first passage of the outer sleeve. A housing having a plurality of ports that communicate hydraulic fluid with the inner sleeve; and a locking pin that is inserted in a one-diameter line direction at the other axial end of the inner sleeve opposite to the axial end near the output shaft. A pressure ring mounted on the inner sleeve, the pressing ring being in contact with a step surface formed on the inner sleeve and the other axial end of the outer sleeve opposite to the one axial end near the output shaft; A spring receiving piece mounted between the stop pin and the pressing ring; a pressing ring interposed between the pressing ring and the housing and supported by the other axial end of the outer sleeve and the stepped surface of the inner sleeve. A first spring for resiliently pressing the direct drive hydraulic servo valve which comprises a second spring interposed between the pressing ring and the spring receiving piece. 2. The direct-drive hydraulic system according to claim 1, further comprising an operation detector for detecting rotation of the output shaft of the motor or displacement of the spool, wherein the detection signal is used to feedback-control the motor. Servo valve. 3. The direct-drive hydraulic servo valve according to claim 1, further comprising a pressure detector for detecting a pressure in the first passage.