Thermoplastics injection-moulded spur gear with bulging teeth - has embedded metal ring to control shrinkage of moulding compound

摘要

Thermoplastics, injection-moulded, spur gearwheel has teeth whose sides bulge spherically. A metal ring intended to control the shrinkage of the thermoplastics moulding cpd., is embedded in the body of the gearwheel and positioned centrally w.r.t. the gear-tooth system. Its outer dia. is slightly smaller than root circle of the gearwheel and its breadth is smaller then the breadth of the teeth. The embedded metal ring controls shrinkage of the thermoplastics such that the moulding can easily removed from the mould. This enables gearwheels with spherically bulding teeth to be simply and cheaply mfd.