Variator control system
AssigneeTorotrak (Development) Limited
InventorsChristopher John Greenwood, Masaki Inui, Mervyn John George Patterson, Yudai Tatara
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Abstract
A variator assembly comprises a variator of the toroidal-race rolling-traction type using double-acting pistons to control the rollers and differential end load pressure to load the variator, and control means operative to vary the differential end load pressure in sympathy with changes in the net pressure exerted by the roller-control pistons so as to maintain the traction coefficient at the roller disc interface consistently below the limit at which traction would be lost.
Claims13
A variator assembly comprising a toroidal-race rolling-traction variator having input and output discs (78,79), at least two hydraulic control pistons being connected to a plurality of rollers, said plurality of rollers (12) being positioned between said discs and operative to transmit traction therebetween, and end loading means (89,50) to bias one of said disc towards the other of said discs, hydraulic control means operative to vary an end load in sympathy with changes in the force exerted by the control pistons so as to maintain the traction coefficient at the roller-disc interface consistently below the limit at which traction would be lost, wherein that the control pistons comprise double-acting pistons controlled by a difference between a pressure of a first hydraulic circuit and a pressure of a second hydraulic circult, and by a high-pressure-wins valve (45,46) located between said first and second hydraulic circuits of said hydraulic control means to supply fluid at a higher of two pressures in the circuits to a high-pressure chamber of the end loading means, a low-pressure-wins valve (63,64) is located between said first and second hydraulic circuits to supply fluid at a lower of two pressures in the circuits to a compensating chamber of the end loading means.
A variator assembly comprising a toroidal-race rolling-traction variator having input and output discs (78,79), at least two hydraulic control pistons being connected to a plurality of rollers, said plurality of rollers (12) being positioned between said discs and operative to transmit traction therebetween, and end loading means (89,50) to bias one of said disc towards the other of said discs, hydraulic control means operative to vary an end load in sympathy with changes in the force exerted by the control pistons so as to maintain the traction coefficient at the roller-disc interface consistently below the limit at which traction would be lost, wherein that the control pistons comprise double-acting pistons controlled by a difference between a pressure of a first hydraulic circuit and a pressure of a second hydraulic circuit, and by a first valve (45,46) communicating with said first and second hydraulic circuits of said hydraulic control means to supply fluid at a higher of two pressures in the first and second hydraulic circuits to a high-pressure chamber of the end loading means, and a second valve (63,64) communicating with said first and second hydraulic circuits to supply fluid at a lower of two pressures in the first and second hydraulic circuits to a compensting chamber of the end loading means.
Dependencies are inferred from the claim text.