Electro-hydraulic backup module for emergency power supply of hydraulic consumers of an aircraft

Abstract

Electro-hydraulic backup module for emergency supply of hydraulic consumers (7) of an aircraft, comprising at least one electric motor pump (1) with at least one motor control (2), at least one accumulator (3), at least one shut-off and accumulator filling valve (4) and at least one distributor (5), wherein at least one pump selection valve (6) is provided which is configured to couple the hydraulic consumers (7) either to a main hydraulic system or to the backup module, characterized in that the pump selection valve (6) includes an integrated heater and an integrated position sensor and that the electric motor pump (1) includes a temperature sensor for detecting the temperature of the stator windings of the motor and that the electric motor pump (1) includes a cooling device with a hydraulic fluid as a cooling medium for cooling the motor.

Description

The invention relates to an electro-hydraulic backup module for the emergency supply of hydraulic consumers of an aircraft, in particular an airplane. The backup module comprises at least one electric motor pump with at least one motor control unit, at least one accumulator, at least one shut-off and accumulator filling valve, and at least one distributor. The invention is further directed to an aircraft such as an airplane with at least one electro-hydraulic reserve module according to one of claims 1-7. Modules for supplying hydraulic fluid to hydraulic consumers in aircraft are known from the prior art, in which electric motors drive hydraulic pumps for decentralized hydraulic fluid supply in aircraft. Such motor-coupled pumps can be referred to as electric motor pumps. Variable-speed motors can be used in conjunction with constant-speed pumps to provide different hydraulic fluid flows. Another architecture known from the prior art can utilize a constant-speed asynchronous motor coupled to a variable displacement pump. This method also makes it possible to provide different or variable flow rates. US patent 2004 / 0195909 A1 discloses an architecture for a hydraulic circuit with a main and an emergency system, which includes an electrically driven pump unit to supply actuators, such as aircraft brakes. US Patent 2011 / 0256000 A1 discloses a local backup hydraulic actuator comprising a 6 / 2-way switching valve and an electronically controlled servo valve for controlling the actuator. DE 36 38 820 A1 describes a rudder control arrangement in which a bypass valve of a hydromechanical actuating system is equipped with a position sensor for monitoring the passive state. US Patent 5,109,672 A describes a system for cooling and refilling hydraulic actuators in an aircraft. It circulates a low-pressure hydraulic fluid to regulate the temperature of the components. The system includes temperature sensors and a cooling unit where the hydraulic fluid serves as the cooling medium. Finally, DE 196 54 781 A1 discloses an auxiliary device for realizing redundancy for flight control drives, which includes a shut-off valve designed as a 4 / 2-way valve. A disadvantage of existing systems is that each actuator on the aircraft requiring hydraulic fluid needs a complete hydraulic system, including a motor, pump, accumulator, electronics, valves, and other components. This increases the overall weight of the aircraft and makes it more difficult to provide redundant hydraulic systems. Against this background, the object of the invention is to provide an improved electro-hydraulic module that is designed to provide a reserve or emergency supply for a plurality of hydraulic consumers of an aircraft. This problem is solved according to the invention by an electro-hydraulic backup module with the features of claim 1. The backup module according to the invention comprises at least one electric motor pump (1) with at least one motor control (2), at least one accumulator (3) for storing hydraulic fluid, at least one shut-off and accumulator filling valve (4) for connecting the accumulator to the hydraulic consumers and / or to the electric motor pump, and at least one distributor (5). The backup module further comprises at least one pump selection valve (6) configured to connect the hydraulic consumers (7) either to a main hydraulic system or to the backup module. According to the invention, the pump selection valve (6) includes an integrated heater and an integrated position sensor.Furthermore, the electric motor pump (1) comprises a temperature sensor for detecting the temperature of the stator windings of the motor and a cooling device with a hydraulic fluid as a cooling medium for cooling the motor. Advantageous embodiments are the subject of the dependent claims. The backup module is a highly efficient, reliable hydraulic module that can be powered by a 28 VDC power supply. In an emergency, such as a failure or malfunction of the aircraft's main hydraulic system, the hydraulic consumers can be selectively supplied by the backup module's hydraulic system and completely isolated from the main hydraulic system. These hydraulic consumers can include, for example, the aircraft's primary control surfaces such as ailerons, spoilers, elevators, and / or rudder. According to the invention, not only is a single hydraulic consumer or actuator supplied via a typically position control system, but several actuators of the flight control system or the aircraft can be redundantly supplied in an emergency with several reserve modules according to the invention via a pressure control system of the reserve module. In a preferred embodiment of the invention, the pump selection valve is a 6 / 2-way valve. The pump selection valve serves to switch the reserve module between an active state and a standby state. The active state can be a state in which the reserve module takes over the hydraulic supply to at least one hydraulic consumer, while the standby state can be a state in which at least one hydraulic consumer is supplied via a main hydraulic system and not via the reserve module. In a further preferred embodiment, the pump selection valve is or comprises an electronically controlled pilot valve. In another preferred embodiment, it is conceivable that the electric motor pump comprises a constant-displacement pump and / or a permanent magnet synchronous motor. The permanent magnet synchronous motor can include a resolver or a position / rotary encoder for position control, and the motor control system can comprise a digital signal processing controller, as well as a control board and a monitor board. A cooling device (or cold plate) can be integrated with the motor control system to dissipate heat losses from the motor into the hydraulic fluid. A case drain (CD) from the constant-displacement pump can be routed through the permanent magnet synchronous motor for cooling purposes, as it is a wet-rotor motor. In another preferred embodiment, it is conceivable that the storage device is a piston storage device, in particular a spring storage device. The accumulator, designed as a piston or spring accumulator, can include an integrated level transducer (LVT) or level sensor required for temperature compensation. Furthermore, the accumulator can be configured to allow hydraulic fluid to be drained from the reservoir or accumulator when the reserve module is active, thus maintaining a leakage reserve. The housing outlet or drain from the permanent magnet synchronous motor can be routed through a housing outlet filter (CD filter), which protects the system from contamination of the pump or electric motor pump. The fluid temperature can be measured in the area upstream of or just before the CD filter. In a further preferred embodiment of the invention, it is conceivable that the shut-off and storage filling valve is a 4 / 2-way valve. In a further preferred embodiment of the invention, it is conceivable that the reserve module is coupled to the main hydraulic system via a leak-free check valve. The invention further relates to an aircraft with at least one electro-hydraulic reserve module according to one of claims 1-7. Further details and advantages of the invention are explained with reference to the embodiments shown by way of example in the figures. These show: Fig. 1: schematic representation of two electrohydraulic reserve modules according to the invention; Fig. 2: schematic representation of the control loops made possible by the invention; and Fig. 3: pressure control curve of an electrohydraulic reserve module according to the invention. Fig. 1 schematically shows two electro-hydraulic backup modules according to the invention, which are provided on an aircraft in addition to a main hydraulic system. The left backup module is coupled to actuators of one wing of the aircraft, while the right backup module is coupled to actuators of the tail assembly. The backup modules serve as an emergency power supply for the aircraft's hydraulic consumers. In the event of a failure of the main hydraulic system, the respective hydraulic consumers can be used or moved by means of the backup modules. A reserve module comprises at least one electric motor pump 1 with at least one motor control 2. Furthermore, each reserve module comprises at least one storage tank 3, at least one shut-off and storage tank filling valve 4, and at least one distributor 5. The electric motor pump 1 can comprise a constant-displacement pump FDP and a permanent magnet synchronous motor PMSM, or more generally, a pump 30 and a motor 20. The motor control 2 can be supplied with electrical energy via a 28 VDC busbar and can also be configured to switch the electric motor pump 1 on and off, perform start-up tests, monitor the overheating of the electric motor pump 1 and generate error messages. The memory 3 can be integrated within a corresponding memory arrangement comprising a level sensor 9, a fluid temperature sensor 10 and a CD filter 11. In the area of ​​the distributor 5, at least one pump selection valve 6 is provided, which is configured to connect the hydraulic consumers 7, which are shown in the lowest area of ​​Fig. 1, to a main hydraulic system or to the reserve module. The hydraulic consumers 7 can be spoilers or airbrakes 71, ailerons 72, thrust reversers, landing gear 74, horizontal stabilizers or elevators left 75 and right 76, rudder 73, or corresponding hydraulic actuators, which may optionally be assigned to the respective wings or sides of the aircraft. In the area of ​​the distributor 5, an HP sensor 12, a check valve 13, an HP filter 14, a pressure relief valve 15 and a leak-free check valve 16 can be provided. The pump selection valve 6 of the right reserve module or empennage HEPP or guide HEPP (electrohydraulic power package) is shown in a standby mode, while the pump selection valve 6 of the left reserve module is shown in an active mode. In standby mode, low-pressure hydraulic fluid is routed back to the main hydraulic system through the pump selection valve 6. This is shown on the right side of Fig. 1. In its activated mode, the pump selection valve 6 blocks the high-pressure and low-pressure lines of the main hydraulic system and connects the high-pressure and low-pressure lines of the PFCS consumers to the HPP circuit. This is shown on the left side of Fig. 1. The pump selection valve 6 can be configured to supply different consumers with hydraulic fluid. These consumers can include additional control components that allow them to be moved using the supplied hydraulic fluid. The shut-off and accumulator filling valve 4 can be designed as a three-stage valve. High-pressure fluid from the main hydraulic system can be routed through a shut-off and accumulator filling valve filter to protect the shut-off and accumulator filling valve 4 from contamination from the main hydraulic system. A first stage of the shut-off and accumulator filling valve 4 can be a solenoid valve, which switches the pre-stage of the valve to move the spool of the 4 / 2-way valve against a spring force as the second stage. The accumulator can be filled with hydraulic fluid via a filling nozzle or a filling port. Filling of the accumulator can continue until a limit pressure of the shut-off and accumulator filling valve 4 is reached. The shut-off and accumulator filling valve 4 can discharge fluid into the main hydraulic system via a check valve. Components of the main hydraulic system are shown in the upper middle section.This includes a low-pressure filter (LPF), a main reservoir (8), a pump (EDP), and a high-pressure filter (HPF). These components can be connected in this order. The main hydraulic system can be connected to aircraft consumers via the two filters (LPF and HPF). A pressure relief valve (PRV) can also be provided, connecting one outlet of the high-pressure filter (HDF) to the main reservoir (8). The pressure relief valve (PRV) can be configured to open a return flow to the main reservoir (8) at an overpressure of approximately 25.85 MPa. Fig. 2 shows the possible configuration of the control loops that can be represented according to the invention. The three control loops shown can be used to maintain a target pressure at the pump outlet. These control loops comprise a pressure control loop, a velocity control loop, and a current control loop. Fig. 3 shows the pressure control curve of the reserve module, with the pressure profile in the wing reserve module shown as a solid line and the pressure profile in the tailplane reserve module as a dotted line. The pressure can be approximately 19.3 MPa with no hydraulic flow and approximately 15.2 MPa with maximum flow. To prevent the electric motor pump from starting at low fluid temperatures, especially below -20 degrees Celsius, and the resulting high motor loads, the motor control can operate in a heating mode when the feedback or signal from the temperature sensor indicates that the fluid temperature is below -20 degrees Celsius. In heating mode, the motor control can maintain the motor speed at a constant value, for example, 3750 revolutions per minute. This constant operation can be maintained until the fluid temperature reaches a value of, for example, 0 degrees Celsius.

Claims

Electro-hydraulic backup module for emergency supply of hydraulic consumers (7) of an aircraft, comprising at least one electric motor pump (1) with at least one motor control (2), at least one accumulator (3), at least one shut-off and accumulator filling valve (4) and at least one distributor (5), wherein at least one pump selection valve (6) is provided which is configured to couple the hydraulic consumers (7) either to a main hydraulic system or to the backup module, characterized in that the pump selection valve (6) includes an integrated heater and an integrated position sensor and that the electric motor pump (1) includes a temperature sensor for detecting the temperature of the stator windings of the motor and that the electric motor pump (1) includes a cooling device with a hydraulic fluid as a cooling medium for cooling the motor. Electro-hydraulic reserve module according to claim 1, characterized in that the pump selection valve (6) is a 6 / 2-way valve. Electro-hydraulic backup module according to claim 1 or 2, characterized in that the pump selection valve (6) is an electronically controlled pilot valve. Electro-hydraulic reserve module according to one of the preceding claims, characterized in that the electric motor pump (1) comprises a constant pump and / or a permanent magnet synchronous motor. Electro-hydraulic reserve module according to one of the preceding claims, characterized in that the accumulator is a piston accumulator, in particular a spring accumulator. Electro-hydraulic reserve module according to one of the preceding claims, characterized in that the shut-off and storage filling valve (4) is a 4 / 2-way valve. Electro-hydraulic reserve module according to one of the preceding claims, characterized in that the reserve module is coupled to the main hydraulic system via a leak-free check valve. Aircraft with at least one electro-hydraulic reserve module according to any one of claims 1 to 7.

Images