Shell and cap for friction shock absorber for washing machines

A shock absorber for washing machines with horizontal axis of rotation, comprising a shell (2) inside which a piston (3) slides, a friction ring (5) positioned around said piston (3) inside said shell and configured to exert a friction action on said piston upon a relative movement between piston and shell, and a cap (4), said cap (4) being provided with a central through hole (46) inside which said piston (3) is introduced,

• and wherein:
• the inner surface of said through hole (46) comprises a plurality of longitudinal grooves (41), among which ribs (43) are interposed, said ribs (43) having a tapered profile from outside towards the center,
• said shell (2) comprises a first portion (21), hollow inside, in which said cap (4) is housed by means of axial introduction, and a second portion (22) in which the piston (3) slides,
• and in that
• said first hollow section (21) is provided with a plurality of circumferential grooves (211) and said cap (4) comprises an abutting surface (44) configured to abut a respective abutting surface (25) of the shell (2) and a portion (45) configured to be introduced in the first portion (21), hollow inside, of said shell (2) and provided with a plurality of circumferential ribs (42) configured to be coupled to said circumferential grooves (211).