RU2230944C2 - Redundant electrohydraulic servo drive - Google Patents

Abstract

FIELD: flying vehicle control system drives.

SUBSTANCE: proposed servo drive has housing with working fluid delivery and drain channels, single-chamber hydraulic actuator with housing channels, series-connected closing/cross-feed valve, electrohydraulic booster and servo cylinder, hydraulic distributor with mechanical non-power wire lead coupled with servo cylinder rod, and hydraulic system selector valve communicating with two independent hydraulic supply systems; hydraulic system selector valve is made in the form of two control devices built in common cylindrical channel at opposite ends of body and separated by isolating bushing; they have shut-off members of valve-seat type each incorporating cap, guide sleeve, and seat-bushing fixed in position in body channel and provided with sealing rings on outer cylindrical surfaces and inner stepped drillings, as well as kinematically intercoupled spring-loaded check valve installed in small-step drilling of seat-bushing and spring-loaded plunger hermetically disposed in large-step drilling of guide sleeve and provided with inner partition carrying spring on one end and control chamber, on other end, this chamber communicating with delivery line and through check valve built in small step of guide sleeve drilling, with delivery channel of actuating mechanism; large-step drillings of seat-bushings of both control devices are interconnected and communicate with drain channel of actuating mechanism; mentioned kinematic coupling is made in the form of stepped cylindrical pusher disposed in small-step drilling of seat-bushing for their axial displacement and engagement with end surface of plunger partition and with ball-shaped shut-off member of check valve through their working butt-ends; guaranteed annular clearance is provided between outer surface of pusher small step and small-step drilling surface of seat-bushing for passing working medium.

EFFECT: enhanced reliability.

2 cl, 6 dwg

Description

The present invention relates to redundant follow-up hydromechanical, single-channel and multi-channel electro-hydraulic drives, which are widely used as actuators in aircraft control systems, and can be used in any industry where highly reliable automatic control systems are used.

Redundant hydraulic drives with replacement of hydraulic systems are known, in which hydropower is supplied from two independent hydraulic systems, one of which is the main one and the other one is a backup. Connection to the drive of the backup hydropower system is carried out by a special hydraulic valve (switching valve), which is automatically activated by the pressure drop in the hydraulic system from which the drive works (see Goniodsky VI and others. Aircraft steering surfaces drive. M.: Engineering, 1974 ., p. 181, Fig. 4.26 (a). The closest in technical essence is the redundant servo electro-hydraulic drive of the helicopter control system (see Germany patent No. 2931533, class F 15 V 20/00, figure 2).

The known redundant servo electro-hydraulic actuator (actuator) contains the maximum number of features similar to the claimed actuator, namely both actuators belong to redundant servo electro-hydraulic actuators for aircraft control systems and contain a single-chamber hydraulic motor with cavity channels, connected in series elements of an automatic control system (solenoid valve , electro-hydraulic power amplifier and servocylinder), hydrodistributors mechanical non-force-wired drive control associated with stocks servo cylinders, hydraulic valve and switch communication with two independent hydraulic power sources.

The advantage of the known drive is that due to the use of a single-chamber executive hydraulic motor, the number of complex structural elements is reduced, the dimensions and weight of the drive are significantly reduced.

However, a significant drawback of this drive is that in order to ensure tightness and minimal overflows from one hydraulic system to another, the cylindrical spool valve used in the switching valve of the known actuator on the outer cylindrical surface must be made with high accuracy and very little roughness and installed in the inner channel of the sleeve or housing with the minimum permissible annular gaps (4 ... 6 microns).

The greater likelihood of “jamming” or aggravating the movement of such a spool during operation (for example, in the event of a possible contamination of the working fluid) leads either to a drive failure, or to instability and an increase in the transfer time of the spool, which significantly reduces the reliability of the drive, while switching on the reserve (emergency) aircraft power supply system should be trouble-free and be carried out almost instantly, because the loss of control of a high-speed aircraft at least for a split second, especially during its post-landing run, may lead to an accident.

In addition, the known drive does not exclude the possibility of subsidence of the actuator rod of the hydraulic motor under the influence of an external load - the articulated moment from the action of aerodynamic loads on the steering surface at a time when they exceed the maximum force developed by the hydraulic drive. The drawdown of the rod, in turn, is accompanied by a sharp push (stroke) of the control handle, which is psychologically perceived by the pilot as a failure or loss of control of the aircraft, which also relates to significant disadvantages of the known drive.

A disadvantage of the known actuator is also the structural complexity of the hydraulic valve switching valve, which is largely due to its location between switchgears (spools) and the hydraulic actuator, as well as the introduction of special devices that prevent the switching of hydraulic power sources during a short-term pressure drop or completely turn off the failed hydraulic power system.

The technical task to be solved is to increase the reliability of the drive and, therefore, the reliability of the control system of the aircraft by increasing the reliability and speed of operation of the switching valve of the hydraulic systems of the drive by connecting the valve to command pressure sources remotely controlled from the cockpit by the signals of the pilot, excluding the precision spool pair from the valve transition to a valve system for distributing the working medium, which ensures high sensitivity due to zero overlap-through windows are eliminated and the conditions for occurrence of the shock (jogging) the load on the pilot control handle at the time of exposure to the maximum air loads on the control surfaces.

The problem is solved in that in the proposed drive for the aircraft control system, comprising a housing with discharge and drain channels for the working fluid, a single-chamber hydraulic motor with cavity channels, a servo-ring solenoid valve, an electro-hydraulic power amplifier and a servocylinder, and a non-power mechanical control valve actuator wiring connected to the servo-cylinder rod and hydraulic switching valve in communication with two independent hydraulic power systems, according to the invention, the hydraulic switching valve is made in the form of two control devices integrated in the common cylindrical channel of the housing and separated by a disconnecting sleeve with locking elements of the valve-seat type, each of which consists of a cover fixedly installed in the channel of the housing body, guide cup and sleeve-saddle with o-rings on the outer cylindrical surfaces and the inner stepped boring and kinematically connected between a spring-loaded check valve installed in the bore of a small stage of the sleeve-seat, and a spring-loaded plunger hermetically placed in the bore of a larger stage of the guide cup and provided with an internal partition, on one side of which a spring is placed, and on the other a working control chamber is formed with the possibility of communicating with inlet pressure line and through a check valve integrated in the small stage of the bore of the guide cup, with the pressure channel of the actuator, while the bore of the larger steps of the sleeve-saddles of both control devices are looped together and communicated with the drain channel of the actuator, and the specified kinematic connection is made in the form of a stepped cylindrical pusher located in the bore of a small stage of the sleeve-saddle with the possibility of axial movement and interaction of its working ends with the end surface the walls of the plunger and the surface of the shut-off element of the non-return valve, made in the form of a ball, and between the outer surface of the small stage olkatelya and the surface of bore bushings low stage-mounted seat guaranteed annular gap for passage of the working medium, and the switching valve is connected to a remotely controlled control pressure sources.

Transferring the switching valve to a valve system for distributing the working medium and forcing remote control of the hydraulic switching valve using electromagnetic valves remotely controlled by the pilot's signal ensures reliable and instantaneous operation of the switching valve in extreme and emergency situations, and installing ball valves in the hydraulic switching valve valves in the lines of the pressure lines (in small steps of the bores of the guide glasses) provides overlap to feed (pressure) at the moment of external load exceeding the maximum force developed by the drive, which eliminates the drawdown of its actuator rod and the occurrence of a shock (push) on the pilot's control handle.

The essence of the invention is illustrated by drawings.

Figure 1 shows a general diagram of a drive with a hydraulic switching valve with remotely controlled sources of command pressure - electromagnetic valves when operating as part of a redundant servo electro-hydraulic actuator in combined control mode, in which manual control through the input link (lever) is corrected by an automatic control system functioning from autopilot signals with the help of a steering machine engaged in a differential circuit.

The drive is equipped with a hydraulic distribution device with a flat rotary valve, characterized by higher reliability, tightness and the absence of danger of “jamming” of moving elements (TM Bashta. Hydraulic drives of aircraft. M .: Mashinostroenie, 1967, p.239).

Figure 2 presents a General view, section of a valve switching hydraulic systems.

Figure 3 shows the General diagram of the switching valve of hydraulic systems with remotely controlled sources of command pressure - electromagnetic valves when operating as part of a hydromechanical steering gear with manual control containing a directional valve with a flat rotary valve.

Figure 4 shows the General diagram of the valve switching hydraulic systems with electromagnetic valves when operating as part of a redundant servo electro-hydraulic actuator with remote control containing a valve with a flat rotary valve.

Figure 5 shows a General view, a section of a switching valve when operating from the first hydraulic power system. An electromagnetic control signal is applied to the solenoid valve 16. The solenoid valve 17 of the second hydraulic power supply is de-energized.

Figure 6 shows a General view, a section of a switching valve when operating from a second hydraulic power system. An electromagnetic control signal is supplied to the solenoid valve 17. The electromagnetic valve 16 of the first hydraulic power supply is de-energized.

The actuator (figure 1) contains a housing 1 with discharge 2 (3) and drain 4 (5) channels for the working fluid, a single-chamber hydraulic motor 6 with cavity channels 7 and 8, an on-ring solenoid valve 9, an electro-hydraulic power amplifier (EHU) 10 and a servocylinder 11, a control valve 12 with non-mechanical mechanical wiring of the actuator 13 connected to the rod 14 of the servocylinder 11, and a hydraulic switching valve 15 connected to two independent hydraulic power systems 2 (4) and 3 (5).

The hydraulic switching valve 15 is connected to command pressure sources - electromagnetic valves 16 and 17, remotely controlled from the cockpit by a pilot signal.

The hydraulic valve switching valve 15 (Figs. 1, 2) is made in the form of two oppositely inserted into the common cylindrical channel 18 of the housing 1 and separated by a disconnecting sleeve 19 of control devices 20 and 21 with locking elements of the valve-seat type, each of which consists of from a cover 22 fixedly installed in the channel 18, a guide cup 23 and a saddle sleeve 24 having internal step-boring bores 25 and 26, respectively, and kinematically connected to each other by a spring-loaded check valve 27 installed in the bore of a small stage 26 in saddles 24 and a spring-loaded plunger 28, hermetically placed in the bore of a larger stage 25 of the guide cup 23 and having an internal baffle 29, on one side of which a spring 30 is placed, and on the other a working control chamber 31 is connected, communicating through the radial channels 32 of the plunger 28 and a guide cup 23 with inlet pressure lines 33 and 34, and through a check valve 35 integrated into the small stage of the bore 25 of the guide cup 23, with a pressure channel 36 of the actuator (valve and steering m ashina).

Bores 26 of the large steps of the sleeve-saddles 24 of both control devices 20 and 21 are looped together by a channel 37 and connected to a drain channel 38 of the actuator. The kinematic connection between the spring-loaded check valve 27 and the spring-loaded plunger 28 is through a stepped cylindrical pusher 39, which interacts with its working ends 40 and 41 with the end surface of the baffle 29 of the plunger 28 and the surface of the check ball of the check valve 27. Between the outer surface of the small pusher stage 39 and the surface the bores 26 of the small stage of the sleeve-saddle 24, a guaranteed annular gap 42 is installed for the passage of the working medium into the drain channel 43 or 44.

The drive in manual control mode operates as follows.

An electrical control signal is supplied to the electromagnetic valve 16 of the first hydraulic power supply system (Figs. 1, 5). The solenoid valve 17 of the second hydraulic power supply is de-energized. Under the influence of the electric control signal, the armature of the electromagnetic valve 16 extends outward (according to the scheme to the left), axially moving the spring-loaded spool on the stroke. In this case, the high pressure radial channels of the valve are connected and provide the passage of the working medium into the control chamber 31 of the control device 20 of the hydraulic switching valve. Further, the working fluid under pressure through the check valve 35 and the inner channel of the uncoupling sleeve 19 enters the cavity of the check valve 35 of another opositely located control device 21.

The locking element (ball) of the valve 35, closing the central channel for supplying pressure from the second hydraulic system, ensures the passage of the working medium into the channel 36 of the supply line to the actuator (electro-hydraulic amplifier 10 (Fig. 1), servocylinder 11, valve 12.

The pilot through the thrust of mechanical non-power wiring 13 moves the control flat spool of the valve 12. The control spool, moving (turning to a certain angle from a neutral position in one direction or another), communicates the corresponding cavity of the hydraulic motor 6 with pressure 2 and drain 4 channels of the power source.

Under the action of operating pressure in the control chamber 31, the plunger 28 of the control device 20, compressing the spring 30, moves to the right with its end surface of the partition 29 into the outer end of the small step of the sleeve-seat 24, axially moving the stepped cylindrical pusher 39, which end of a small stage 41 presses a spring-loaded locking element (ball) 27 from the saddle-sleeve 24, providing passage of the drain pressure coming from the hydraulic motor through the channel 37, through the annular gap 42 into the drain channel 43, into the electromagnet channels valve 16 and into the drain line of the first hydraulic system.

Similarly, when the electric control signal is applied to the electromagnetic valve 17 (Figs. 1, 6), the working pressure of the second hydraulic system is supplied to the control chamber 31 of the control device 21, from where it enters the same channel 36 of the supply line to the control valve 12 through the check valve 35, and the drain from the hydraulic motor to the drain line of the second hydraulic system occurs through the check valve pressed by the pusher 39, the check valve 27 of the control device 21 and the drain channel 44.

The drive in combined control mode (manual control with correction from the automatic control system) works as follows.

Electrical signals are sent to the electromagnetic valve 16 of the first hydraulic power system, to an electro-hydraulic power amplifier (EGU) 10 from an automatic control system (autopilot), and an on-ring solenoid valve 9 (Fig. 1,5).

In this case, as in the first case, the working fluid from the first hydraulic supply system is supplied to the control valve 12, which provides manual control of the hydraulic motor 6. The cavities of the servocylinder 11 are slid off and the working fluid flows to the EHU. The working fluid from the EHU through the on-ring valve 9 enters the working cavities of the servocylinder 11, which, moving, moves the flat spool of the hydraulic distributor rigidly connected to it 12. The control spool, moving, communicates the corresponding working cavities of the hydraulic motor with a pressure 2 or drain 4 channels of the power source .

The pilot's control signals and signals from the servocylinder are summed up, which determines the direction, magnitude and speed of movement of the actuator's actuator rod.

The drive at the time of exposure to maximum aerodynamic loads on the steering surfaces of the aircraft operates as follows (Fig.1, 2).

The working cavity of the hydraulic motor cylinder 6 is connected through a sewage system and a control valve to ball check valves 35 mounted at the inlet of the discharge channels 33 and 34 of the shift valve 15. At the time of the maximum aerodynamic load of any sign on the steering surfaces of the aircraft, the check valve 35 of the switch valve of the functioning control system locks the working fluid of the hydraulic cylinder 6, so that the shock load from the articulated moment on the control handle Niemann fluid trapped in the cylinder. The drive in this case works as a damper, providing easy and smooth control of the aircraft.

An actuator with a shift valve improves the reliability and efficiency of the actuator itself and, therefore, the reliability of the aircraft control system, due to:

- exceptions to the design of the switching valve of a precision spool pair, prone to “jamming” in cases of operation on a contaminated working fluid, and the transition to a valve system for distributing a working medium,

- connecting the switching valve to remotely controlled sources of command pressure,

- eliminating the occurrence of shock load on the pilot's control handle at the time of the maximum aerodynamic loads on the steering surfaces of the aircraft.

Claims (2)

1. A redundant servo electrohydraulic actuator for the aircraft control system, comprising a housing with discharge and drain channels for the working fluid, a single-chamber hydraulic motor with cavity channels, a servo-ring solenoid valve, an electro-hydraulic power amplifier and a servo cylinder, a control valve with mechanical non-power drive wiring, connected to the stem of the servo-cylinder, and a hydraulic switching valve, coupled with two independent hydraulic power systems, characterized in that the hydraulic switching valve is made in the form of two oppositely built-in control devices with locking valve-saddle elements, separated into the common cylindrical channel of the housing, each of which consists of fixedly installed in the housing channel cover, guide cup and sleeve-saddles with O-rings on the outer cylindrical surfaces and the inner stepped boring and kinematically connected between the battle of a spring-loaded check valve installed in the bore of a small step of the sleeve-seat and a spring-loaded plunger hermetically placed in the bore of a larger stage of the guide cup and provided with an internal partition, on one side of which a spring is placed, and on the other a working control chamber is formed with the possibility of communicating with supply pressure line and through a check valve integrated in the small stage of the bore of the guide cup, with the pressure channel of the actuator, while the bores are more The upper stages of the sleeve-saddles of both control devices are looped together and communicated with the drain channel of the actuator, and the specified kinematic connection is made in the form of a stepped cylindrical pusher placed in the bore of a small stage of the sleeve-saddle with the possibility of axial movement and interaction of its working ends with the end surface the walls of the plunger and the surface of the shut-off element of the non-return valve, made in the form of a ball, and between the outer surface of the small stage Catel and the surface of the bore of the sleeve of the saddle-mounted low level guaranteed annular gap for passage of the working medium. 2. The actuator according to claim 1, characterized in that the hydraulic valve switching valve is connected to remotely controlled sources of command pressure.

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