Twin Screw Extruder And Torque Splitting Transmission
A twin screw extruder and torque splitting transmission has two output shaft portions
that are axially spaced apart a distance and are connected to elongate shafts where at least one is bent along its length and powered by a driven pinion gear that has a diameter that is greater than the distance between the axes of the twin screws.
splitting transmission for driving the closely spaced twin screws. The pinion gear size is limited as a function of the center distance between the shafts. In one extreme, the diameter of the driven pinion gears cannot be greater than the distance between two co-rotating shafts. In another extreme where the drive gear pinions are axially offset from the other, one of the pinion gears cannot have a radius that is greater than the difference between the distance between the shafts and the radius of one shaft.
The prior art solutions show that the output torque of a transmission may be at best doubled by engaging two teeth of a small diameter pinion gear whose diameter is limited by the distance between the axes of the twin screw extruder. The torque output capability of such gearing is less than the torque handling capability of the twin screws and thus, is a limiting factor in the output capacity of the twin screw extruder.
In accordance with the invention, a twin screw extruder and a torque splitting transmission are provided wherein the torque splitting transmission has two output shaft portions that are axially spaced apart a distance substantially equal to the distance between the axes of twin screws. At least one of the output shafts is bent along its length and powered by a driven pinion gear having a diameter that is greater than the distance between the axes of the twin screws. The larger size pinion gear substantially enhances the output torque capability of the transmission and consequently, the torque capacity of the transmission approaches or equals the torque carrying capacity of the twin screws. Improved output torque capacity results in an extruder with substantially improved throughput capability.