US 2011/0256000 A1Published application

Local backup hydraulic actuator for aircraft control systems

AssigneeNabtesco Corporation

InventorAtsushi Fukui

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Abstract

A backup system is provided that has a local electric motor and pump for some or all of hydraulic actuators. A local backup hydraulic actuator has two power sources, hydraulic as primary and electrical as backup. During normal operation, the hydraulic actuator receives pressurized fluid from a hydraulic system and the fluid flow to the chambers is controlled by a servo valve. If the hydraulic system fails, the electronic controller detects the failure by observing the signal indicative of the pressure from the pressure sensor, and the controller powers the local hydraulic pump to provide high pressure hydraulic fluid to the hydraulic actuator via the servo valve.

Claims12

Dependent claims

A hydraulic control system comprising:

a hydraulic actuator having a cylinder and piston assembly;
first and second fluid lines coupled to the hydraulic actuator;
a high pressure fluid line;
a low pressure fluid line;
a central pressure source coupled to the high pressure fluid line to place high pressure on the first and second fluid lines;
a servo valve positioned between the central pressure source and the hydraulic actuator and being controllable to selectively connect the first and second fluid lines to the high pressure fluid line and the low pressure fluid line to control movement of the hydraulic actuator;
a variable displacement pump adjacent to the servo valve, the variable displacement pump being coupled to the high pressure fluid line upstream of the servo valve to place pressure on the high pressure fluid line;
an electric motor connected to the variable displacement pump to drive the variable displacement pump;
a pump mechanism controlling a pressure from the variable displacement pump by changing a fluid displacement of the variable displacement pump, the pump mechanism placing the pressure from the variable displacement pump on the high pressure fluid line;
a first check valve in the high pressure fluid line adjacent to the servo valve, the first check valve preventing the high pressure fluid from entering from the variable displacement pump to the central pressure source;
a second check valve adjacent to the variable displacement pump, the second check valve preventing the high pressure fluid from entering from the central pressure source to the variable displacement pump;
and
a controller which performs (i) a sequential-power mode in which, when the pressure from the central pressure source is lost, supply of the pressure to the high pressure fluid line is maintained by placing pressure from the variable displacement pump to the high pressure fluid line by activating the electric motor and (ii) a parallel-power mode in which, when it is required to switch the pressure source quicker than in the sequential-power mode, the electric motor is activated in advance for a failure of the central pressure source so that the pressure from the central pressure source and the pressure from the variable displacement pump are simultaneously supplied to the high pressure fluid line.

10 more elements

A local pump unit for controlling a hydraulic actuator, said local pump unit comprising:

a first plurality of hydraulic ports;
an electric motor;
a variable displacement pump coupled to said first plurality of hydraulic ports and powered by said electric motor to provide a high pressure fluid output to the hydraulic actuator;
a pump mechanism controlling a pressure of the high pressure fluid output from the variable displacement pump by changing a fluid displacement of the variable displacement pump, the pump mechanism supplying the high pressure fluid output from the variable displacement pump to the hydraulic actuator via a servo valve;
a second plurality of hydraulic ports connecting a central pressure source with the local pump unit, the central pressure source supplying the high pressure fluid output to the hydraulic actuator via the servo valve;
a first check valve provided between the variable displacement pump and the central pressure source, the first check valve preventing the high pressure fluid output from entering from the variable displacement pump to the central pressure source;
and
a second check valve provided between the variable displacement pump and the central pressure source, the second check valve preventing the high pressure fluid output from entering from the central pressure source to the variable displacement pump,
the electric motor being connected to a controller which performs (i) a sequential-power mode in which, when supply of the high pressure fluid output from the central pressure source is lost, supply of the high pressure fluid output to the hydraulic actuator is maintained by supplying the high pressure fluid output from the variable displacement pump to the hydraulic actuator by activating the electric motor and (ii) a parallel-power mode in which, when it is required to switch the source of the high pressure fluid output quicker than in the sequential-power mode, the electric motor is activated in advance for a failure of the central pressure source so that the high pressure fluid output from the central pressure source and the high pressure fluid output from the variable displacement pump are simultaneously supplied to the hydraulic actuator.

6 more elements

A method for operating a hydraulic actuator that receives fluid pressure from a central pressure source, the method comprising:

activating the variable displacement pump adjacent to said hydraulic actuator and coupled upstream of a servo valve, on a high pressure fluid line, to perform a sequential-power mode in which, when the fluid pressure from the central pressure source is lost, supply of the fluid pressure to the hydraulic actuator is maintained by supplying the fluid pressure from the variable displacement pump to the hydraulic actuator;
activating the variable displacement pump to perform a parallel-power mode in which, when it is necessary to switch the source of the fluid pressure quicker than in the sequential-power mode, the fluid pressure from the central pressure source and the fluid pressure from the variable displacement pump are simultaneously supplied to the hydraulic actuator in advance for a failure of the central pressure source;
controlling the fluid pressure from the variable displacement pump by changing a fluid displacement of the variable displacement pump;
supplying the fluid pressure from the variable displacement pump to the hydraulic actuator;
providing increased fluid pressure to the high pressure fluid line adjacent to the hydraulic actuator, while preventing the fluid pressure of the variable displacement pump from entering the central pressure source by a first check valve and preventing the fluid pressure of the central pressure source from entering the variable displacement pump by a second check valve;
moving the servo valve in a first direction to provide the high pressure fluid to a first side of the hydraulic actuator;
and
moving the servo valve in a second direction to provide the high pressure fluid to a second side of the hydraulic actuator.

5 more elements

Dependencies are inferred from the claim text.

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Abstract

A hydraulic control system comprising:

a hydraulic actuator having a cylinder and piston assembly;
first and second fluid lines coupled to the hydraulic actuator;
a high pressure fluid line;
a low pressure fluid line;
a central pressure source coupled to the high pressure fluid line to place high pressure on the first and second fluid lines;
a servo valve positioned between the central pressure source and the hydraulic actuator and being controllable to selectively connect the first and second fluid lines to the high pressure fluid line and the low pressure fluid line to control movement of the hydraulic actuator;
a variable displacement pump adjacent to the servo valve, the variable displacement pump being coupled to the high pressure fluid line upstream of the servo valve to place pressure on the high pressure fluid line;
an electric motor connected to the variable displacement pump to drive the variable displacement pump;
a pump mechanism controlling a pressure from the variable displacement pump by changing a fluid displacement of the variable displacement pump, the pump mechanism placing the pressure from the variable displacement pump on the high pressure fluid line;
a first check valve in the high pressure fluid line adjacent to the servo valve, the first check valve preventing the high pressure fluid from entering from the variable displacement pump to the central pressure source;
a second check valve adjacent to the variable displacement pump, the second check valve preventing the high pressure fluid from entering from the central pressure source to the variable displacement pump;
and
a controller which performs (i) a sequential-power mode in which, when the pressure from the central pressure source is lost, supply of the pressure to the high pressure fluid line is maintained by placing pressure from the variable displacement pump to the high pressure fluid line by activating the electric motor and (ii) a parallel-power mode in which, when it is required to switch the pressure source quicker than in the sequential-power mode, the electric motor is activated in advance for a failure of the central pressure source so that the pressure from the central pressure source and the pressure from the variable displacement pump are simultaneously supplied to the high pressure fluid line.

10 more elements