The Techroll joint is a constant-volume, fluid-filled bearing configured with a pair of rolling convolutes that permits omniaxis deflection of a solid rocket motor nozzle. The fluid-filled bearing is pressurized by nozzle ejection loads and serves as both the movable nozzle bearing and nozzle seal. The Techroll seal is made of a fabric-reinforced elastomeric composite material and does not require complex manufacturing processes or tight tolerances.
The Techroll joint has undergone development under U.S. Air Force, Navy, and Army funding and has been demonstrated on six separate contracts involving 12 different designs. This paper introduces the concept, presents four of the designs, and summarizes the performance characteristics of seven designs.