Abstract: A variator having at least one roller which runs upon at least one race to transfer drive from one to the other at variable ratio. The variator has a fluid supply for supplying fluid to the race and roller thereby to provide a fluid film by which the roller and the race are separated in use. The roller has a running surface with root means square roughness Rq(roller) and the race having a root means square roughness Rq(race). The variator's specific film thickness is the minimum thickness of the fluid film in normal operation divided by the composite roughness, and is less than 1.0. At least one of the roller and the race has a powder metal surface with a Ra roughness above 0.1 micrometers.

Abstract: A variator has an input shaft (18), an input disc (10) mounted coaxially with the input shaft and rotatable by the input shaft, an output disc (12) facing the input shaft (18) and being mounted coaxially with the input disc, a toroidal cavity defined between the input and output discs and a plurality of rollers (14, 16) located in the toroidal cavity, in rolling contact with the input and output discs (10, 12), each of the rollers being mounted on a roller carriage (17). The variator has means (34) for applying an end load to the variator to urge the rollers (14, 16) into contact with the input and output discs (10, 12) and resiliently deformable means for applying a reaction force to each of the roller carriages.

Abstract: A transmission of the toroidal race rolling traction type, including ratio varying components (“variators”) for such transmissions. A set of rollers transmitting traction between an input disc and an output disc is connected to a hydraulic mechanism by which it is positioned, the roller position determining the transmitted ratio.

Abstract: The invention concerns a kinetic energy recovery system for use in a vehicle driveline. The system has a flywheel (24) serving to store energy. A continuously variable transmission (32) serves to transfer drive between the flywheel and a driveline of the vehicle at a steplessly variable CVT speed ratio. The continuously variable transmission has a variator (34) which has a rotary variator input (40) and a rotary variator output (42). The variator serves to transfer drive between its input and output at a continuously variable variator speed ratio. The continuously variable transmission further comprises a shunt gear arrangement (36) having a first rotary shunt input which is drivably coupled to the rotary variator input, a second rotary shunt input which is drivably coupled to the rotary variator output, and a shunt rotary output which is drivably coupled to the flywheel.

Abstract: The invention is concerned with control of a motor vehicle powertrain having a transmission of torque-controlled type. The powertrain also has an engine which provides a controllable engine torque. The method involves determining a reaction torque requirement and an engine torque requirement suitable to create a desired wheel torque and also a desired engine acceleration. The engine torque and the reaction torque provided by the transmission are set accordingly. The invention is characterized by the fact that the aforementioned calculation involves estimating and allowing for vehicle acceleration.

Abstract: A variator (2) having a pair of semi-toroidally recessed races (11, 12) mounted to a housing (6) for rotation about a common variator axis. A roller (14) is mounted between the races to transfer drive between them at a variable drive ratio. A sun gear (25) is mounted between the races, as is a ring (gear 26). The ring gear is radially outboard of the sun gear. Mounted between the sun and ring and meshing with both is a carrier gear (33) upon which the roller is mounted in a manner which enables it to both spin about its own axis, when turned by the races, and also to tilt relative to the races to vary the drive ratio. A control pinion (27) is also arranged between the sun and ring gears meshing with both. The control pinion is able to rotate about its own axis freely, but the pinion axis is fixed with respect to the housing.

Abstract: There is disclosed a continuously variable ratio transmission assembly (“variator”) comprising a roller which transmits drive between a pair of races, the roller being movable in accordance with changes in variator ratio, a hydraulic actuator which applies a biasing force to the roller, at least one valve connected to the actuator through a hydraulic line to control pressure applied to the actuator and so to control the biasing force, and an electronic control which determines the required biasing force and sets the valve accordingly, wherein the valve setting is additionally dependent upon a rate of flow in the hydraulic line.

Abstract: A transmission is disclosed for a wheeled vehicle. The transmission has a rotary input (14) to be driven by a rotary power source, e.g. an internal combustion engine. It has a rotary output (16) for driving a vehicle wheel. A transmission unit is coupled between the rotary input and the rotary output to transfer drive between them at a speed ratio which is continuously variable through a range which includes both negative ratios (providing a reversal of rotational direction between the rotary input and the rotary output), positive ratios (in which the rotary input and the rotary output rotate in the same direction), and a geared neutral ratio, in which the rotary output is stationary. In accordance with the invention, the transmission further comprises a brake (20) for braking the rotary output. The brake is provided with a control arrangement adapted to apply it when the speed ratio is set to the geared neutral ratio and to release the brake as the speed ratio is adjusted away from the geared neutral ratio.

Abstract: The invention concerns an electronic controller for a continuously variable transmission of the type having a variator (10) with a rotary variator input (17) coupled to a first variator race (14a) and a rotary variator output (29) coupled to a second variator race (16a). At least one roller (20) runs upon the said races to transfer drive from one to the other. The roller is movable to steplessly vary the variator ratio. The variator further comprises at least one hydraulic actuator (36), (38) which acts upon the roller and through which net torque acting on the variator races is referred via the roller to the variator's casing. A hydraulic arrangement is provided for applying to the actuator at least one hydraulic control pressure which determines force applied’ by the actuator and thus determines the reaction torque. The variator is coupled between a rotary transmission input (17) and a rotary transmission output (714) such that the transmission ratio is a function of the variator ratio.

Abstract: A method for controlling a continuously variable ratio transmission is described. The method may include controlling a continuously variable ratio unit (“variator”) having rotary input and output members through which the variator is coupled between an engine and a driven component, the variator receiving a primary control signal and being constructed and arranged to exert upon its input and output members torques which correspond directly to the control signal. The method may also include determining a target engine acceleration, determining settings of the variator's primary control signal and of an engine torque control for providing the required engine acceleration and adjusting the control signal and/or the engine torque control based on these settings, predicting a consequent engine speed change, allowing for engine and/or transmission characteristics, and correcting the settings of the control signal and engine torque based on a comparison of actual and predicted engine speeds.

Abstract: A multi-regime continuously variable ratio transmission has a transmission input shaft, a transmission output shaft, and a ratio varying unit having a rotating input and a rotating output, the rotational axes of the input and the output being coaxial. A shunt having first and second epicyclic gear sets is connected across the ratio varying unit. One gear set has an input driven by the input shaft and an input driven by one side of the ratio varying unit and the other gear set has an input from the first gear set and an input from one side of the ratio varying unit. The gear sets rotate about a common axis and are offset with respect to, and parallel to, the rotational axes of the input and output of the ratio varying unit. A clutch is operable to selectively connect the output of the second gear set to the output shaft.

Abstract: System comprising an epicyclic arrangement. In some embodiments, the epicyclic arrangement can comprise: a first input element; a second input element fixed to an input drive shaft; a geared carrier that includes at least a portion that is disposed axially between the first and second input elements, the geared carrier being engaged with an output member; and planets associated with the geared carrier. Some embodiments of the present systems comprise a housing in which the epicyclic arrangement is disposed; and/or fluid contained within the housing.

Abstract: A transmission arrangement for use with a motor vehicle which has left and right hand transmissions 200L, 200R. A left hand variator 204L, 404L comprises a left hand input race 222L driveable from a transmission input 220, 520, 620 and a left hand output race 226L, 426L, 626L. A set of left hand variator rollers 224L is arranged to transmit drive between the left hand input race and the left hand output race. The left hand variator rollers are moveable to permit continuous change in the ratio of rotary speed of the left hand input to that of the left hand output race. A left hand epicyclic unit 210L has two left hand epicyclic inputs 226L, 234 driveable along with the left hand input race and the left hand output race. A left hand epicyclic out 234 drives a left hand transmission output 240L, 440L, 640L. A right hand transmission is formed in similar manner.

Abstract: A variator transmission comprises an input shaft (18), an input disc (10) mounted on the input shaft for rotation therewith and an output disc (12) facing the input disc and arranged to rotate coaxially therewith, the input and output discs defining between them a toroidal cavity. Two rollers (14, 16) are located in the toroidal cavity and first and second roller carriage means are provided upon which the first and second rollers respectively are rotatably mounted and end load means (34, 36) urge the rollers into contact with the input and output discs to transmit drive. The two roller carriage means are mounted on opposite sides of the pivotal axis of a lever (50) and the pivotal axis of the lever (50) is movable in both the radial and non-radial directions with respect to the rotational axis of the input and output discs.

Abstract: Variators that include a damped roller control part.

Abstract: The invention concerns an arrangement for controlling a vehicle drivetrain having an engine provided with a speed governor and a continuously variable transmission (“CVT”) incorporating a variator which is constructed and arranged to regulate its reaction torque. The control system comprises a control part (504) movable by the driver to provide a driver input, an open loop subsystem (511) for operatively coupling the control part to the governor (520) to control no-load speed of the governor in dependence on the driver input, a closed loop subsystem comprising a comparator (502) which receives a first control signal deprived from the driver input and corresponding to a target engine speed, and a second control signal corresponding to engine speed, and which adjusts variator reaction torque in dependence upon a comparison of the first and second control signals causing the transmission to load the engine suitably to achieve the target engine speed.

Abstract: A drive arrangement is disclosed for a motor vehicle power take off (PTO). The arrangement comprises a PTO shaft 104,158,207 of a known type intended for coupling to a power driven implement. An input shaft is arranged to be coupled to a rotary driver such as an engine. A continuously variable transmission such as 10 is coupled between the input and PTO shafts to transfer drive between them at a continuously variable ratio. In accordance with the invention, the continuously variable transmission is constructed and arranged such as to regulate torque and to automatically accommodate changes in speed at the PTO Shaft by virtue of changes in its drive ratio.

Abstract: A continuously variable transmission having a variator (5) comprising input discs (2) coupled to an input shaft (12) and an output disc (3) providing a rotary variator output. The input and output discs are mounted for rotation about a common axis and at last one roller (4) is arranged between the discs to transfer drive from one to the other at a continuously variable variator drive ratio. The roller is mounted in a carrier (30) in a manner which permits it to spin about its own axis and to tilt relative to the disks to vary the variator drive ratio. A hydraulic actuator (22) is arranged to apply to the carrier (30) a reaction force determined by a hydraulic pressure difference acting on the actuator. The reaction force opposes a traction force applied to the roller (4) by the action of the discs (2, 3).

Abstract: In a continuously-variable-ratio-device of the type having races between which drive is transferred by rollers which are movable in accordance with changes of variator ratio, it is necessary to apply a traction load urging the rollers and races into engagement. Each rollers is also subject to a transverse reaction force by a hydraulic reaction roller actuator receiving a controlled reaction pressure. It is desirable to create a relationship between traction and reaction force, and also to provide for adjustment of this relationship. In the present invention this is achieved hydraulically. A traction pressure related to the reaction pressure is applied to an actuator which creates the traction load. The hydraulics also include a working chamber, which is selectively connectable to and disconnectable from either (or both) of (i) the reaction pressure and (ii) the traction pressure, the traction force being dependent upon pressure in the working chamber.

Abstract: A continuously variable transmission having a transmission input (60) and a transmission output (114) is described. The transmission has a variator (56). This is a device which transmits drive at steplessly variable ratio. It further comprises an epicyclic gear arrangement (58) incorporating a clutch arrangement (152). The epicyclic gear arrangement has three rotary members. One of these is coupled to a planet carrier (86) having at least one planet gear (94). Another of the rotary members is coupled to a main gear (90) meshing with the planet gear. The clutching arrangement serves to couple the remaining rotary member to either of first and second alternative gears (96, 98), both of which mesh with the planet gear and which rotate at different speeds. One of the aforesaid rotary members is coupled to the transmission input at a fixed drive ratio. One of them is coupled to the variator output. The last of the rotary members is coupled to the transmission output.