The PIV infinitely variable gear is a universally recognised device whose carefully studied design, proven operational safety and versatility make it easily adaptable to a wide variety of applications in all branches of both mechanical engineering and manufacturing industry.
All Torque Transmissions supplies and services PIV gear units.
PIV Gear Design
Essential elements of all PIV gears are two pairs of conical wheels which are movable on their shafts in an axial direction and are connected by a special chain. An opposite axial movement of the conical wheels will change the pitch circle of the chain and thereby the speed of the output shaft.
The system A gear has conical wheels with radial grooves and a slatted tooth chain. The laterally movable slats engage the tooth spaces of the conical wheels and transmit the adjusted torque through contact. Slip free power transmission, maximum accuracy of speed setting and good maintenance of the adjusted ratio are features of this design.
The system R gear has been developed, an in many instances higher speed and wider speed ranges as well as lower power ratings are required. The conical wheels of this type are smooth. The chain consists of cylindrical rollers, pivotably mounted on their longitudinal axes, and transmits the torque through pressure action.
All moving parts of both types of PIV gear are manufactured from high grade steel and run in an oil bath. The chain tension is maintained through an automatic re-tensioning device.
PIV Gear Servicing
All moving parts of the gear are automatically lubricated by splash lubrication. The temperature of the gear depends on the load, the circulation of air, and the room temperature. According to the load the gears will warm up to from 40 to 70 degrees C above room temperature. The temperature of the oil should not exceed 90 degrees C. Servicing is limited to checking the oil filling and to changing the oil as required by the operating instructions. The life of the gear corresponds to that of toothed wheels and ball bearings, when working conditions are normal and servicing instructions are observed.