A screw actuator (2) comprises a nut (6) having an internal helical formation (8) and a screw (4) having an external helical formation (12) and rotatably received within the nut (6), relative rotational movement of the nut (6) and screw (4) causing axial movement of one of the nut (6) and screw (4) relative to the other of the nut (6) and screw (4). The actuator (2) further comprises a lubricant reservoir (30) and a lubricant pressuriser (34) for pressurising lubricant (22) within the lubricant reservoir (30). A lubricant receiving chamber (40) is formed in the nut (6). The screw (4) extends through the lubricant receiving chamber (40). A lubricant supply passage (42) fluidly connects the lubricant reservoir (30) and the lubricant receiving chamber (40). A valve (64) controls the flow of lubricant (22) between the lubricant reservoir (30) and the lubricant receiving chamber (40). A lubricant supply piston (44) is received in the lubricant receiving chamber (40) and is (44) mounted on the external helical formation (12) of the screw (4). The lubricant supply piston (44) is mounted to the screw (4) with sufficient friction that in response to relative rotational movement of the screw (4) and the nut (6) resulting in relative axial movement of the screw (4) and the nut (6), the lubricant supply piston (44) can move axially with the screw (4) relative to the nut (6) through the lubricant receiving chamber (40) so as to force lubricant (22) from the lubricant receiving chamber (40) into an interface (28) between the nut (6) and the screw (4), but such that the lubricant supply piston (44) may rotationally slip on the screw (4) when the lubricant supply piston (44) reaches an axial limit position within the lubricant receiving chamber (40).
LUBRICATION OF SCREW ACTUATORS
LUBRIFICATION D`ACTIONNEURS DE VIS
2021-04-17
Patent
Electronic Resource
English
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