GB1113312A - Improvements in or relating to viscous shear rotary dampers - Google Patents

Abstract

1,113,312. Viscous shear rotary damper. HOUDAILLE INDUSTRIES Inc. 9 Aug., 1965, No. 34025/65. Heading F2S. A viscous shear rotary damper unit comprises a liquid-filled housing 7 having end plates 8, 39 and a cylindrical shear film working surface 23 opposite a complementary cylindrical damper surface 24 on a damper sleeve 25 which is torsionally coupled by splines 27 to a cylindrical flange 21 on the head portion 20 of a shaft 5 rotatably supported in the end plate 8 by ball bearings 11, 12 and 14, 15, the axial position of the sleeve 25, which is biased towards the end plate 39 by a spring 38, being controlled by a thermostatic bi-metallic device 31 which varies the area of confrontation of the working surfaces 23, 24 as a function of liquid temperature. The device 31 comprises a bi-metallic washer stack which is guided over a reservoir tube 42 and which acts between the end plate 39 and a flange 32 on a thrust sleeve 33 which has an outwardly extending flange 34 bearing against a flange 37 on the outer end of the damper sleeve 25 through a roller bearing assembly 35, the corresponding end of the sleeve 25 being held concentric by nylon pellets 29 which are seated in circumferentially spaced sockets 30 in the outer surface of the sleeve. A replenishing piston 45, with a seal 49 and loaded by a spring 5, is slidable within the reservoir tube 42 and has a rod 47 which extends through a ring nut 48 threaded into the end plate 39, the damper being fillable through a longitudinal bore 50 which has a check valve assembly 51 and is closable by a plug 55. The projection of the rod 47 beyond the nut 48 provides an indication of the amount of liquid in the damper, and also its thermal expansion, the spring 52 ensuring a moderate replenishing pressure on the liquid. During filling air is evacuated from one, or more, bleed-off ports 53 each having a plug 54. Minor corrections for temperature compensation may be accomplished e.g. by tapering either of the damper surfaces 23, 24. A bellmouth 41, as shown, may be adjusted by flaring at the angle desired.