Rolls-royce Corporation

Michael C Roberts

John F Leonard

Ian Makin

The invention is related to a fastener assembly of the kind used to secure a gas turbine engine rotor disc assembly on a shaft in a situation which otherwise would required the use of a trapped nut. It thereby removes a design constraint limiting bore diameter of the disc assembly to permit access to a securing nut on the shaft, and avoids the use of a trapped nut. One of the rotors hubs is adapted to be mounted on the shaft and the securing nut is engaged with a thread on the shaft to trap the hub. In the improvement of the invention the hub is provided with an axial keyway through which the securing nut is passed into the limited access space. Once the shaft is engaged with the hub the nut is then engaged with the thread on the shaft and tightened using a special tool extending through the centre of the shaft. The tool is withdrawn after use. The nut may be undone and retrieved in an opposite operation.

Fastener assembly

A firtree profile, for example on a component of a gas turbine engine, is formed in a two-stage process. In one stage, an intermediate profile is formed, for example by a mechanical machining operation such as grinding. Subsequently, in a second stage, loaded flanksof the profile are formed by an electric discharge machining operation performed on the intermediate profile. Alternatively, the electric discharge machining operation may be performed first to create the intermediate profile, and subsequently transition regions, such as fillets, may be formed in a mechanical or chemical material removing operation. In the resulting profile, surfaces, such as the loaded flanks, which must be finished to tight tolerances, but which are subjected to relatively low bending stresses, are formed by the electric discharge machining operation, which leaves a re-cast layer. In regions subjected to higher bending stress, such as regionsof the fillets, are formed by mechanical or chemical metal removal techniques, and so do not have the re-cast layer

Forming firtree profiles

An actuator arrangement for moving a first component relative to a second component, the arrangement comprising: an actuator chamber for receiving a fluid under pressure, a side wall of the chamber being fixed relative to the first component; an actuating element fixed relative to the second component and located inside the chamber for sliding movement along the chamber, relative to the side-wall; and a sealing element which provides a corresponding sliding seal between the actuating element and the sidewall for maintaining an actuating fluid pressure differential across the actuating element thereby to drive the actuating element relative to said side-wall, under said fluid pressure differential, for driving said relative movement of the first and second components; wherein the arrangement further comprises an external side-wall brace connected to the second component for corresponding movement with the actuating element along the outside of the sidewall, the brace being slidably or rollably braced against the outside of the side-wall close to the sealing element thereby to provide respective local reinforcement of the side-wall at or near the sliding seal, in accordance with the position of the actuating element.

Actuator arrangement for vectorable nozzles of gas turbine

A gasket or seal member constructed of elastomeric material has at least one slot extending lengthwise of the member and across its thickness at an oblique angle to the sealing faces. There may be a plurality of slots spaced apart across the width of the member. In a preferred form of the invention multiple, parallel slots are formed at an oblique angle to the seal faces of the member forming branchiate-like layers of gasket material, in which each of the layers partially overlays at least one other layer.

Multi-layer gasket or seal member

The present invention provides an actuating apparatus for moving relatively rotatable components. In one embodiment the apparatus comprises: a bearing () including first () and second () relatively rotatable bearing elements for mounting respective first () and second () rotatable components for relative rotation about a common axis; a pneumatic or hydraulic actuator having a pair of co-acting parts (), including a first part () fixed with respect to the said first rotatable element and a second part () fixed with respect to the said second rotatable element; and, means () for energising and/or de-energising said actuator means to effect movement of the said co-acting parts and thereby relative rotation of the said first and second bearing elements about the said bearing axis. The actuator may comprise at least one chamber () defined between a pair of relatively rotatable annular members () each having at least one dividing element () extending into the chamber to divide the interior of the chamber into separate circumferential regions (). Pressure differentials generated in the chamber across one or more of the dividing elements effect relative rotation of the first and second bearing elements.

Apparatus for moving rotatable components

The present invention provides a seal assembly for sealing between two relatively slideable members of non-circular cross-section. A plurality of adjacent seal members may be staggered and grouped within a groove so that all leakage surfaces between the two relatively slideable members are sealed. Multiple seal members or seal member groups may be used to reduce leakage caused by incomplete contact of the seal members with leakage surfaces. An actuator system may comprise various embodiments of the present invention to enable the actuation of one member in relation to another.

Seal assembly

In a gas turbine engine tip clearance between rotor blades and an encircling shroud liner is controlled by moving the shroud liner radially to match the thermal and centrifugal growth of the rotor assembly. The shroud liner segments are suspended between two axially displaced control rings located in a passageway carrying air ducted from the compressor. One control ring responds very quickly to changes in gas temperature corresponding to centrifugal growth and blade thermal growth. The other ring responds very much more slowly and corresponds to the thermal growth of the disc. The shroud liner segments are suspended from the control rings to adopt a position that constitutes the average between the growth positions of the two control rings.

Rotor shroud assembly

An air seal is disposed between high and low pressure zones and includes an annular static arm and coaxial annular sealing arm which rotates relative to the static arm. The static arm, is scalloped to form a series of cavities and the sealing arm is formed with angled through holes opposite the cavities. A seal is provided between the static arm and the sealing arm. In use, a ram pressure rise is generated in the holes by the rotation of the sealing arm and the pressure rise creates a flow of air which offsets the leakage past the seal.

Seal arrangement

In a gas turbine engine, a turbine blade vibration damper is located between the underside of a blade platform and a turbine disc, and comprises a member which extends axially parallel to the blade roots. The member has on its outer surface an inverted 'V' shaped projection which engages a complementary shaped recess in the underside of the blade platforms. The member has two limbs of unequal length. Centrifugal forces on the longer limb rocks the member and urges the shorter limb into engagement with the disc rim.

Growing community of inventors

Bristol, United Kingdom

Michael C Roberts