Abstract: A fluid display arrangement is disclosed for a rolling-traction continuously-variable ratio transmission unit in which drive is transmitted from one race to another by at least one rotating roller whose outer circumference engages the races, the fluid supply arrangement comprising a shroud mounted in proximity to the roller and a fluid supply conduit, and being characterised in that the shroud has an inner surface providing a circumferential portion adjacent the roller's outer circumference and two radially extending portions adjacent respective flanks of the roller, a fluid receiving chamber being thereby defined between the roller and the shroud, and the fluid supply conduit being arranged to deliver fluid into the fluid receiving chamber.

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 the radial direction with respect to the rotational axis of the input and output discs.

Abstract: A multi-regime continuously variable ratio transmission system has coaxial system input and output shafts (16, 24), a continously variable ratio transmission unit (V) connected coaxially to the system input shaft (16) and having a coaxial variator output shaft (18) and a mixing epicyclic gear train (E1) having an input sun gear (S1) drivably connected to the variator ouput shaft (18), a planet carrier (C1) drivably connected to the system input shaft (16) and a planet gear (P1) mounted on the planet carrier ((C1). The planet gear (P1) drives a first intermediate output shaft (22) arranged coaxially with the system input shaft (16) and selectively connectable to the system output shaft via a first clutch (H) in high-regime operation of the transmission. The planet gear (P1) also provides the input for a second epicyclic gear train (E2) having an output (C2) which is selectively connectable to the system output shaft via a braking element (L) for low-regime operation of the transmission.

Abstract: A transmission comprises a toroidal variator having first and second spaced-apart drive discs (12, 14) defining a toroidal cavity about a rotational axis (x-x), a transmission input (22) arranged to drive the first and second drive discs (12, 14) in opposite directions and supported on pivotal mountings between the drive discs (12, 14), one or more rollers (18, 20) arranged to contact the said drive discs (12, 14) and be driven thereby, wherein the transmission output (44) is driven by orbiting of the pivotal mountings around the rotational axis of the variator.

Abstract: A variator assembly comprising a variator of the toroidal-race rolling-traction type. The assembly has input and output discs and rollers which are acted on by hydraulic roller control actuators. They 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. Reaction pressure supply means are connected to the roller control actuators to cause them to apply an adjustable reaction force to the rollers. The assembly also has hydraulically influenced valve means which serve to compare an input related to the end load pressure with an input related to the reaction pressure and to control the end load pressure in dependence upon the comparison, thereby maintaining a relationship between the end load and reaction pressures.

Abstract: 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.

Abstract: The present invention provides an hydraulic control circuit for a continuously-variable-ratio transmission An hydraulic control circuit for a CVT transmission includes a first hydraulic pressure control valve V1 for controlling the pressure of hydraulic fluid to be supplied to the roller control pistons of the variator and a second hydraulic pressure control valve V2 for controlling the pressure of hydraulic fluid to be supplied to a clutching arrangement of the transmission. Said valves V1, V2 are connected in flow series and by a first fluid directing valve means V3(S1, S2) for directing flow from each pump PL, PR to a first point P upstream of valve V1 or to a second point P downstream of valve V1 but upstream of valve V2. By adopting such an arrangement it is possible to control the clutches without affecting the roller position and vice versa.

Abstract: An Orthogonal Frequency Division Multiplexed (OFDM) power line communications system comprising a power line for distributing electricity to a plurality of premises and a communication station coupled to the power line at one of the premises, which station uses a part of the power line external to the premises as a communications medium. The communications station includes a receiver which comprises a clipping system adapted to clip an incoming OFDM data waveform, which includes a regular impulsive noise component, so as to reduce the level of noise on the waveform.

Abstract: A drive mechanism for an infinitely-variable-transmission in which a relatively flexible member 32 connects one or other of the discs 14 to the shaft 10, thereby to accommodate a degree of shaft flexing without distortion of the toroidal cavity.

Abstract: A roller control system for a continuously-variable-ratio transmission (CVT) of the toroidal-race rolling-traction type. The system includes an operating mechanism having a first part (5, 6) operable to control the position of the roller center along the torus center circle but incapable of defining the tilt angle (36) adopted by the roller (7), and a second part comprising a mechanical link (13) connected to the roller bearings and operable to control the tilt angle (36). The link (13) lies substantially parallel to the plane of the roller (7) and is constrained to pass through a predetermined single point (14).

Abstract: A position servo system exemplified by a power-assisted steering system in which a power-driven continuously-variable-ratio transmission ("CVT") of the variable-ratio-epicyclic type, and particularly of the toroidal-race rolling-traction type, is arranged coaxially with the wheel or other rotary actuating member and the steering or other driven mechanism, and delivers an output to augment the steering effort in response to an error between the positions of the actuating member and the steering mechanism. Mechanisms described to prevent interference with the normal manual connection between the actuating member and the steering mechanism should the CVT cease to rotate, and on occasions when the normal sense of operation is reverse and the steering mechanism tends to steer the actuating member. Mechanisms are also described, where the CVT is of the toroidal-race type, to ensure quality between the forces exerted on the steering mechanism by all its connections with the CVT.

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.

Abstract: A roller assembly (10) for use in a toroidal-race rolling-traction variator or like device includes a roller mounted in a carriage (19) which is provided with passageways (33) so that cooling oil from the variator lubrication circuit can be sprayed on to the roller rim via apertures in the carriage and/or in two specially-located spray-bars 38,39 extending from the carriage.

Abstract: A hydraulic control system (70) for a multi-regime CVT (8) includes regime-change clutches (37, 38) which are controlled independently of the variator (10) so that a smooth change of regime may be effected.

Abstract: A variator for a continuously-variable-ratio transmission (CVT) of the half-toroidal traction roller type in which a ratio change results when a roller exercises a first freedom of movement by rotating about a first or precession axis. In addition, the roller mounting has a further freedom of movement about a second or tilt axis. The precession axis is inclined at an angle ("the castor angle") to a plane lying normal to the axis of the races and each equilibrium value of the ratio angle correlates with a unique angular orientation of the roller about the tilt axis.

Abstract: A method of controlling a vehicle driveline including an engine, a continuously variable ratio transmission (CVT) and a final drive in which over a working range of engine speed, the engine is constrained to work to a performance map correlating each value of engine speed to a particular value of engine torque wherein a demand by a driver for a increase in vehicle speed initiates a quick increase in engine speed to a predetermined engage speed without any substantial rise in the final drive speed and then increasing both engine speed and drive speed by a predetermined function until a selected engine speed limit is reached which is commensurate with the driver's demand, and finally maintaining the selected engine speed limit despite further changes in the final drive speed whereby the ratio range of the CVT is extended by providing two regimes of operation with a synchronous ratio between those regimes and the predetermined function is graphically represented as a straight line slope which corresponds to the

Abstract: A continuously-variable-ratio transmission ("CVT") of the band-and-sheave type capable of "torque control", so that what the operator demands, by movement of the accelerator pedal or other control member, is a particular driving torque applied to the ratio-varying components ("variator") A connection (21, 22) between at least one of the variator sheaves (3, 4) and its shaft (5) is torque-sensitive, so that torque at that sheave generates an axial force which is a function of the magnitude and direction of the torque to which the sheave is subjected. Examples are described in which the operating axial load, applied to the variator pulley units, comprises two parts--a first part to maintain traction between sheaves and band, and a second part related to the applied torque--and a variator using more than one band.

Abstract: A continuous-variable ratio transmission comprising a ratio-varying unit ("variator"), and an epicyclic unit having three outputs arranged concentrically. Two of those outputs are connected respectively in fixed ratio to opposite ends of the variator, so that as the variator ratio changes, the speed of one of these outputs always rises and that of the other falls. These two outputs are also connected by appropriate gearing and clutches to the CVT output shaft. Successive regimes of operation, so extending the overall ratio range of the CVT, are obtained by alternatively connecting each of the two epicyclic outputs to the CVT output. Ratios and other parameters are chosen so that regime changes are synchronous.