Torotrak (development) Limited

Thomas G Fellows

Christopher John Greenwood

Philip Duncan Winter

Geoffrey B Soar

A multi-regime continuously variable ratio transmission system has coaxial system input and output shafts (), a continously variable ratio transmission unit (V) connected coaxially to the system input shaft () and having a coaxial variator output shaft () and a mixing epicyclic gear train (E) having an input sun gear (S) drivably connected to the variator ouput shaft (), a planet carrier (C) drivably connected to the system input shaft () and a planet gear (P) mounted on the planet carrier ((C). The planet gear (P) drives a first intermediate output shaft () arranged coaxially with the system input shaft () and selectively connectable to the system output shaft via a first clutch (H) in high-regime operation of the transmission. The planet gear (P) also provides the input for a second epicyclic gear train (E) having an output (C) which is selectively connectable to the system output shaft via a braking element (L) for low-regime operation of the transmission. The arrangement minimises the number of gear meshes, thereby minimising transmission losses and the absence of an annulus in the mixing epicyclic gear train (E) allows more freedom in the choice of gear sizes, thereby permitting reduced gear speeds.

Continuously variable ratio transmission system

Continuously-variable-ratios transmissions

Continuously variable transmission capable of torque control

Continuously-variable-ratio transmission having an improved starting

Continuously-variable-ratio transmissions

Continuously-variable-ratio-transmissions

Continuously-variable ratio transmission of the toroidal race rolling

Transmission of the toroidal-race rolling-traction type

Transmission of the toroidal-race, rolling-traction type having a mixer

A roller control system for a continuously-variable-ratio transmission of the toroidal race, rolling traction type, in which rollers (60) of variable orientation transmit traction between a part-toroidal race (85) formed on an input disc (61) and a similar race (87) formed on a coaxial output disc (62). Each roller is mounted to rotate about a fixed centre (66) and a fixed axis (58) within a rigid carriage (67), one end of which contacts operating mechanism reciprocable over a predetermined stroke of operating movement and operable to apply a control force to the carriage. The assembly of roller and carriage is located by only three contacts with adjacent structure, namely the two disc/roller contacts (86, 88) and the contact (82) with the operating mechanism. These three contacts suffice to cause the roller constantly to seek a ratio angle at which the instantaneous value of the control force is balanced by the instantaneous value of the traction forces to which the roller assembly is subjected due to the contact between the roller and the two discs, and at which the transmission is therefore in equilibrium.

Transmissions of the toroidal-race rolling-traction type

Drivelines for wheeled vehicles

Growing community of inventors

Barnet, United Kingdom

Thomas G Fellows