Head screw for cylinder head and main bearing of IC engine

摘要

The screw (1) has a thread for screwing into an internal screw thread of a first component (2), enabling a second component (3) to be fixed to the first by the screw head. The yield varies along the length of the screw thread. This variation in yield is attained through the ductility or plasticity of the screw material. The yielding of the screw material is higher than that of the internal screw thread at least at the free end of the screw shaft. The yield of the screw material increases in increments along the axis of the screw. The screw is made of steel and is finished by differing age-hardening or heat treating processes along its axial length.