CONTINUOUSLY VARIABLE RATIO TRANSMISSION
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A N oil-film-drive transmission employ ing hardened steel rollers running between toroidal-surfaced discs and giving continuously variable ratio characteristics is under development by the National Research Development Corporation following the design and construction of six test transmissions by Perbury Engineering, Ltd. The gear was invented by Mr. F. G. de B. Perry. A.M.I.Mech.E., A.F.R.Ae.S., and the transmission so far built can transmit an input torque of 100 lb.-ft, over the whole range, this range being 4.7 to 1 (2.7 to 1 speed reduction to 1.75 to 1 speed increase). Ratio changes are effected by altering the angles of the rollers relative to the input and output discs, loading between the discs and rollers being provided by a hydraulic cylinder.
The principle of the transmission is similar to that of the American Hayes type, as fitted by the Austin Motor Co., Ltd., to certain vehicles in the 1930s.