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: A continuously variable ratio device (“variator”) is disclosed in which a pair of rotary races (252, 254) is mounted for rotation about a common variator axis (218). Drive is transferred from one race to the other through at least one roller (200) running upon them. The drive ratio is variable by virtue of precession of the roller about a precession axis (228). Precession results in a change in angle between the roller axis and the variator axis and a corresponding change in drive ratio. In accordance with the invention, the roller (200) is coupled to a carrier (214) in a manner which permits it to precess relative to the carrier (214). The carrier itself is rotatable about a carrier axis (226) which is non-parallel to the precession axis. Rotation of the carrier (214) about the carrier axis serves to change the orientation of the precession axis (228) and is accompanied by a change in variator drive ratio.

Abstract: A transmission arrangement is disclosed which comprises first and second variators (166, 169) each of which comprises an input race (150, 154) and an output race (152, 156). A plurality of rollers (276, 278) is arranged to run upon the input and output races to transfer drive from one to the other. The races are mounted for rotation about a common axis and the inclination of the first variator's rollers is variable independently of the inclination of the second variator's rollers, so that the two rollers are able to provide independently and continuously variable drive ratios. To provide traction between the rollers and races, a biasing device (216, 217) applies an axial force to one of the races, urging the rollers and races into engagement with each other. Each variator is provided with a shunt gear for providing forward, reverse and g eared neutral ratios, and to couple the variator input to the shunt gear a coupling member (160) passes through the outer variator races.

Abstract: A continuously variable ratio transmission unit having a housing (116) and input (102, 106) and output (100) discs paired to define first and second toroidal cavities. The discs (100, 102, 106) are mounted to the housing for rotation about a common axis. First (110) and second (112) rollers—or more typically first and second sets of rollers—are respectively arranged in the first and second cavities and serve to transmit drive between the input and output discs. First (130) and second (148, 150, 152) actuators act on the respective rollers. The first actuator is coupled to a first carrier part (126) which can be mated with the housing introducing it to the housing along a direction generally parallel to the variator axis. The second actuator is coupled to a second carrier part (146) which can be mated with the housing by introducing the second carrier part to the housing along a direction non-parallel to the variator axis.

Abstract: A continuously variable ratio transmission unit having first and second discs mounted for rotation about a main axis, a toroidal cavity being defined between the discs by facing surfaces thereof and containing a plurality of rollers which serve to transmit drive from one disc to the other, each roller being coupled to a respective carriage through a respective bearing arrangement and each carriage being coupled at a first extremity to a first linear actuator and at a second extremity to a second linear actuator whereby the carriage is movable along a direction transverse to the main axis, the first and second linear actuators working in opposition to exert an adjustable net force on the carriage, the orientation of the carriage being constrained and the bearing arrangement being such as to enable the roller to rotate about a roller axis to thereby transmit drive from one of the discs to the other and also being such as to enable the roller axis to precess relative to the carriage to vary the transmission rati

Abstract: A continuously variable ratio device (“variator”) is disclosed in which a pair of rotary races (252, 254) is mounted for rotation about a common variator axis (218). Drive is transferred from one race to the other through at least one roller (200) running upon them. The drive ratio is variable by virtue of precession of the roller about a precession axis (228). Precession results in a change in angle between the roller axis and the variator axis and a corresponding change in drive ratio. In accordance with the invention, the roller (200) is coupled to a carrier (214) in a manner which permits it to precess relative to the carrier (214). The carrier itself is rotatable about a carrier axis (226) which is non-parallel to the precession axis. Rotation of the carrier (214) about the carrier axis serves to change the orientation of the precession axis (228) and is accompanied by a change in variator drive ratio.

Abstract: A control unit for an infinitely-variable-ratio transmission. The transmission includes a cylinder and a piston with a proximal and a distal end. A support stem is connected to the piston. The piston is hollow and has a head portion for interaction with an associated actuation fluid. A proximal portion extends away from the head portion. The support stem is connected to the proximal portion by an articulated joint and extends from the joint to the head portion to exit from the distal end of the piston.

Abstract: A control system (34) suitable for controlling the rollers (26) in an infinitely-variable-ratio transmission (10) is provided with an hydraulic piston arrangement (36) in which a roller support stem (38) is connected to a proximal end (42) of said piston and passes through a piston head (40) via hollow portion (44) within said piston (36) before exiting therefrom.

Abstract: Disclosed is a supply of hydraulic actuation and cooling fluid to the roller actuation pistons and rollers provided in an infinitely variable transmission. The transmission assembly (10) includes a split casing (12a, 12b) and a manifold (28) that comprises one or more channels (30, 32, 60) formed in a surface of the casing formed by the split. The provision of said manifold in this position allows for easier manufacture and better performance.

Abstract: A roller control unit for a CVT includes a cylinder (54) having a piston (70) positioned therein and operably connected to a roller assembly of said CVT thereby to control its position. The unit includes a lubrication supply which comprises a chamber (94) between the cylinder (54) and piston (70) and one or more radially extending passageways (102) through said piston (70). These passageways are in flow communication with the roller and act to direct cooling fluid to said roller. Radial supply of said lubrication facilitates a reduction in flow losses within the supply.

Abstract: A roller control unit (2) for a continuously-variable-ratio transmission includes a cylinder (6) having a cylinder wall and an end wall; and a piston (8), within the cylinder (6) and to which the roller assembly (4) is connected for movement therewith, said unit includes an axially extending shroud (10) of variable length extending between the piston (8) and the end wall, thereby to define in combination with the piston (8) and cylinder (6) a chamber (16) for receiving hydraulic fluid, and in which the shroud (10) comprises a telescopic shroud which in a first position of the piston (8) is extended and in a second position of the piston (8) is retracted.

Abstract: The present invention relates to the supply of hydraulic actuation and cooling fluid to the roller actuation pistons and rollers provided in an IVT. The IVT assembly (10) includes a split casing (12a, 12b) and a manifold (28) that comprises one or more channels (30,32,60) formed in a surface of the casing formed by said split. The provision of said manifold in this position allows for easier manufacture and better performance.

Abstract: An IVT assembly (10) comprises an outer casing (12) and a plurality of hydraulically operated roller control pistons (16). The pistons (16) are mounted in a cylinder block (14) and hydraulic fluid is supplied to said pistons via an hydraulic supply manifold (26) which comprises one or more channels (28, 30) formed within a surface of one of the components of the assembly (10).

Abstract: A composite selector fork arrangement adapted to cooperate with a selector shaft to resist rotational and translational movement relative to the selector shaft. The arrangement also being adapted to cooperate with a selector sleeve to effect translational movement of the selector sleeve. The arrangement including a first and second metallic portion. The first metallic portion being arranged to impart stiffness to the fork arrangement in a direction generally in line with the axial extent of a selector shaft and the second metallic portion being arranged to impart stiffness to the fork arrangement in a direction generally transverse to the axial extent of a selector shaft. The arrangement including a non-metallic portion being arranged to at least partially surround the first and second portions, and in which, in use, the non-metallic portion cooperates with a selector shaft to assist in resisting rotational movement of the selector fork arrangement relative to the selector shaft.