Patent ID: 7497671

Claim:
A hermetic compressor comprising: an electric driving element; a compressing element driven by the electric driving element; and a closed vessel for housing the electric driving element and the compressing element, wherein the compressing element comprises: a shaft having an eccentric shaft portion, a spindle portion provided at a bottom surface of the eccentric shaft portion, and an auxiliary shaft portion provided at a top surface of the eccentric shaft portion so as to be coaxial with the spindle portion; a cylinder block provided with a compression chamber; a main bearing provided on the cylinder block so as to support the spindle portion; an auxiliary bearing provided on the cylinder block so as to support the auxiliary shaft portion; a piston reciprocating in the compression chamber; and a connecting member for connecting the piston and the eccentric shaft portion; wherein a first balance weight is provided on the auxiliary shaft portion at a top end of the eccentric shaft portion; wherein a second balance weight is provided on the spindle portion at a bottom end of the eccentric shaft portion; wherein the first balance weight is coupled to the auxiliary shaft portion by a separate member having a head portion and a base portion, the diameter of the base portion being smaller than the diameter of the head portion, the auxiliary shaft portion being provided with a hole through which the base portion passes, the separate member being arranged between the first balance weight and the auxiliary shaft portion so that the base portion is fixed with the first balance weight and the head portion is in contact with the auxiliary shaft portion; and wherein the auxiliary shaft portion and the first balance weight are provided with a concave part and a convex part, respectively, such that the concave part and the convex part fit together so as to position the first balance weight.