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AssigneeTorotrak (Development) Limited
InventorsChristopher John Greenwood, John William Edward Fuller
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A variator assembly is disclosed comprising a variator of the toroidal-race rolling-traction type having input and output discs, rollers which are acted on by hydraulic roller control actuators and are positioned between the discs to transmit torque from one disc to the other and hydraulic end loading means (200) supplied with fluid at an end load pressure to apply an end load to bias the discs and the rollers toward each other thereby enabling the transmission of torque. The assembly further comprises reaction pressure supply means connected to the roller control actuators to cause them to apply an adjustable reaction force to the rollers. In accordance with the invention hydraulically influenced valve means (204) are provided which respond to the reaction pressure and the end load pressure to control the end load pressure and thereby maintain a relationship between the end load and reaction pressures. Further adjustment means (350) to adjust the relationship between the end load and reaction pressures.
A variator assembly comprising a variator of the toroidal-race rolling-traction type having input and output discs, rollers which are acted on by hydraulic roller control actuators and are positioned between the discs to transmit torque from one disc to the other, hydraulic end loading means supplied with fluid at an end load pressure to apply an end load to bias the discs and the rollers toward each other thereby enabling the transmission of torque, and reaction pressure supply means connected to the roller control actuators to cause them to apply an adjustable reaction force to the rollers, the assembly further comprising hydraulically influenced valve means responsive to the reaction pressure and the end load pressure to control the end load pressure and thereby maintain a relationship between the end load and reaction pressures, and adjustment means to adjust the relationship between the end load and reaction pressures.
A variator assembly as claimed in any preceding claim wherein the valve means comprise a pilot operated valve receiving a hydraulic reaction pressure input signal taken from a connection to the reaction pressure supply means.
A variator assembly as claimed in any preceding claim wherein the roller control actuators are double acting and are connected to first and second reaction pressure supply means, the pressures from which oppose each other in determining the force applied to the rollers, a further valve arrangement being connected across the first and second supply means to direct the higher of the two pressures to the valve means.
A variator assembly as claimed in any preceding claim further comprising a pressure modifying arrangement which receives as an input pressure one of the reaction pressure and the end load pressure, which modifies this pressure to create an output pressure which is a function of the input pressure and which applies the output pressure to the valve means.
A variator assembly as claimed in any preceding claim wherein the valve means has at least two states in which it serves to connect the end loading means respectively to
A variator assembly as claimed in any preceding claim wherein the adjustment means are electronically controlled in dependence upon measured variator operating parameters.
Dependencies are inferred from the claim text.