Rotary damper
A rotary damper comprising a fixed structure, a rotor configured to rotate about an axis (R-R), and two opposing bellows. The bellows each extend between the rotor and the fixed structure and are attached thereto. The bellows each define a chamber for holding hydraulic fluid and are configured to expand and contract as the rotor rotates. The damper further comprises a damping orifice extending through the rotor or the fixed structure. The bellows are sealingly engaged around the damping orifice and the damping orifice permits fluid communication between the chambers defined by the bellows.
1 . A rotary damper comprising:
a housing;
a fixed structure connected to the housing;
a rotor configured to rotate about an axis (R-R) relative to the fixed structure and including a projection that extends outwardly therefrom;
two opposing bellows each extending between and attached to both the rotor and the fixed structure, wherein the bellows each define a chamber for holding hydraulic fluid and are configured to expand and contract as the rotor rotates;
a damping orifice extending through the projection of the rotor such that fluid on one side of the projection can pass through the projection to another side of the projection as the projection rotates due to rotation of the rotor,
wherein the bellows are sealingly engaged around the damping orifice and the damping orifice permits fluid communication between the chambers defined by the bellows;
wherein the two opposing bellows are only in fluid communication with each other via the damping orifice and any fluid passing through the damping orifice is confined to the two opposing bellows;
wherein the damping orifice comprises:
a first opening at a first side of the rotor or the fixed structure;
a second opening at a second opposing side of the rotor or the fixed structure; and
a restriction between the first and second openings configured to restrict hydraulic fluid flow therethrough in order to damp the rotation of the rotor; and
wherein the housing surrounds the rotor and the bellows, wherein the housing comprises: first and second stop members circumferentially-spaced from each other relative to the axis (R-R) of rotation of the rotor;
wherein the rotor comprises a third stop member, wherein the third stop member is configured to engage the first or second stop member in order to limit the rotation of the rotor.
2 . The rotary damper of claim 1 , wherein the bellows are attached to the rotor and/or the fixed structure via a weld, for example, an electron beam weld.
3 . The rotary damper of claim 1 , wherein the rotor includes a shaft extending along the axis (R-R) and a projection extending radially from the shaft, and the bellows are attached to the projection.
4 . The rotary damper of claim 1 , wherein a radially inner surface of the housing and/or a radially outer surface of the rotor includes a wear liner thereon.
5 . The rotary damper of claim 4 , wherein the wear liner comprises:
a friction reducing lining material; and
a friction reducing coating.
6 . The rotary damper of claim 5 , further comprising:
a friction reducing surface treatment selected from one of: a self-lubricating bronze lining material; a PTFE coating; a diamond-coating; and a case-hardened surface.
7 . The rotary damper of claim 1 , wherein the rotor or the fixed structure includes a bleed valve in fluid communication with the bellows,
wherein the bleed valve is configured to allow bleeding of fluid from the bellows or filling of the bellows with hydraulic fluid.
8 . The rotary damper of claim 7 , wherein the bleed valve is a bleed screw or a bleed nipple.
9 . The rotary damper of claim 1 , wherein the bellows comprise stainless steel.
10 . An actuator comprising:
the rotary damper of claim 1 .
11 . A control surface actuation system for an aircraft comprising:
the actuator that includes a rotary damper of claim 1 ; and
an aircraft control surface;
wherein the actuator is operatively connected to the aircraft control surface.