Patent ID: 12208882

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Referring toFIG.1, an aircraft10has a fuselage12. The aircraft10also has a pair of wings14that are attached to the fuselage12. The aircraft10further comprises engines16that are attached to the wings14.

The aircraft10has a plurality of high-lift devices18, such as slats20and flaps22. The high-lift devices18are driven by a power control unit or PCU24. The PCU24outputs torque to drive shafts25that are connected to the high-lift devices18in a manner known per se. In order to arrest the high-lift devices18in a predetermined position, wing tip brakes26are arranged near the end portions of the drive shafts25.

The PCU24is part of a drive system28configured to drive the high-lift devices18and a hydraulic system30configured to drive other aircraft components, such as landing gears or cargo doors. The PCU24is controlled by a corresponding control device32that controls the PCU24in correspondence with the pilot's operation of an input device34.

Referring toFIG.2, the PCU24comprises a motor control electronic or MCE36, an electric motor38, a transmission device40, a hydraulic pump42and a differential output transmission44. As depicted, these parts can be doubled up, so as to provide redundancy. It is also possible that instead of doubling up, a different arrangement of parts is used. Furthermore, it is also possible that only a single arrangement of these parts is present.

The MCE36is connected to an aircraft electric system37in a manner known per se. The MCE36is configured to control the electric motor38and electrically connected to the electric motor38.

The output shaft of the electric motor38is mechanically coupled to the transmission device40.

The transmission device40is mechanically coupled to the hydraulic pump42and the output transmission44.

In a variant it is also possible that the electric motor38is directly coupled to the transmission device40and the hydraulic pump42using two output shafts of the electric motor38.

The transmission device40includes a transmission member46. The transmission member46can be configured as a gear assembly48that has a plurality of gears. The gear assembly48may comprise two spur gears, for example. The electric motor38is coupled to the transmission member46via a torque input49. The transmission member46is coupled to the output transmission44via a torque output51and to the hydraulic pump42via a second torque output53.

The transmission device40includes a torque switching device50. The torque switching device50is arranged so as to enable preventing and allowing of torque transmission between the transmission member46and the output transmission44. The torque switching device50has a power-off brake52for preventing and allowing torque transmission. It should be noted that it is also possible to use a normal-open clutch instead.

The hydraulic pump42is integrated into a hydraulic circuit54. The hydraulic circuit54provides hydraulic consumers56with the required hydraulic pressure. The hydraulic pump42converts torque that it receives into hydraulic pressure.

The output transmission44comprises an output shaft58. The output transmission44can be coupled to torque consumers, such as the high-lift devices18.

Subsequently, the operation of the PCU24is described.

The PCU24operates in two modes: a high-lift mode and a hydraulic mode. In the high-lift mode, the electric motor38drives via the transmission device40the hydraulic pump42and the output transmission44. The output transmission44transmits the torque via its output shaft58to the high-lift devices18thereby driving them into the desired position. The high-lift devices18of the high-lift system can be held in the gated position by the torque switching device50of the PCU24. The WTB26can be used to arrest the high-lift devices18in failure cases (e.g., transmission disconnect etc.).

As the case may be, the PCU24can be switched into the hydraulic mode, e.g., if there is a high flow demand for extending the landing gear. In the hydraulic mode, movement of the output shaft58is arrested via the wing tip brakes26acting as locking devices60. It should be noted that this can also be achieved via a separate locking device60suitably arranged at the output transmission44.

In both modes, the torque switching device50is in a state which allows torque transmission from the electric motor38to the hydraulic pump42and the output transmission44. Due to the output transmission44being a differential transmission, the torque is redirected towards the hydraulic pump42.

The torsional tension present in the drive train from the output transmission44to the high-lift devices is known and can be released by known methods.

If neither hydraulic nor mechanical output is needed from the PCU24, the electric motor38is switched of and the system is arrested by the torque switching device50, e.g., by engaging the power-off brakes52.

Referring toFIG.3, another embodiment of the PCU24is described only insofar as it differs from the previous embodiment. In this embodiment, the gear assembly48is configured as an epicyclic gear box.

The transmission device40includes an additional torque switching device150. The additional torque switching device150is arranged so as to enable preventing and allowing of torque transmission to the hydraulic pump42. The torque switching device150has an additional power-off brake152for preventing and allowing torque transmission. It should be noted that it is also possible to use a normal-open clutch instead.

Subsequently, the operation of the PCU24is described.

The PCU24operates in two modes: a high-lift mode and a hydraulic mode. In the high-lift mode, the electric motor38drives via the transmission device40the output transmission44. The torque switching device50is disengaged and allows torque transmission from the electric motor38to the output transmission44. The additional torque switching device150is engaged and prevents torque transmission from the electric motor38to the hydraulic pump42. As a result, the output transmission44transmits the torque via its output shaft58to the high-lift devices18, thereby driving them into the desired position.

As the case may be, the PCU24can be switched into the hydraulic mode, e.g., if there is a high flow demand for extending the landing gear. In the hydraulic mode, the torque switching device50is engaged, thereby preventing torque transmission from the electric motor38to the output transmission44. The additional torque switching device152is disengaged so as to allow torque transmission from the electric motor38to the hydraulic pump42. As a result, the hydraulic pump42is able to pressurize the hydraulic fluid.

The torque switching device50and the additional torque switching device150are in opposite states for both modes, thereby redirecting the torque of the electric motor38either to the hydraulic pump42(hydraulic mode) or to the output transmission44(high-lift mode).

With this embodiment torsional tension in the drive train from the output transmission44to the high-lift devices18can be avoided.

If neither hydraulic nor mechanical output is needed from the PCU24, the electric motor38is switched of and the system can be arrested by the torque switching devices50,150, e.g., by engaging the respective power-off brakes52,152.

In order to improve the versatility of PCUs (24), the invention proposes a power control unit (24) that can supply hydraulic pressure and mechanical torque. To this end, the power control unit (24) comprises an electric motor (38) that is coupled to a differential output transmission (44) and a hydraulic pump (42). A switchable transmission device (40) allows the torque of the motor (38) to be redirected either to the output transmission (44), e.g., for driving high-lift devices, or to the hydraulic pump (42), e.g., for extending or retracting landing gears.

While at least one exemplary embodiment of the present invention(s) is disclosed herein, it should be understood that modifications, substitutions and alternatives may be apparent to one of ordinary skill in the art and can be made without departing from the scope of this disclosure. This disclosure is intended to cover any adaptations or variations of the exemplary embodiment(s). In addition, in this disclosure, the terms “comprise” or “comprising” do not exclude other elements or steps, the terms “a” or “one” do not exclude a plural number, and the term “or” means either or both. Furthermore, characteristics or steps which have been described may also be used in combination with other characteristics or steps and in any order unless the disclosure or context suggests otherwise. This disclosure hereby incorporates by reference the complete disclosure of any patent or application from which it claims benefit or priority.

LIST OF REFERENCE SIGNS

10aircraft12fuselage14wing16engine18high-lift device20slat22flap24hydraulic power control (PCU)25drive shaft26wing tip brakes (WTB)28drive system30hydraulic system32control device34input device36motor control electronic (MCE)37aircraft electric system38electric motor40transmission device42hydraulic pump44differential output transmission46transmission member48gear assembly49torque input50torque switching device51torque output52power-off brake (POB)53second torque output54hydraulic circuit56hydraulic consumer58output shaft60locking device150additional torque switching device152additional power-off brake (APOB)