Patent ID: 8814539
Filing Date: 2014-08-26
Classification: F04B,F16J

Abstract:
1. A hermetic compressor comprising: a closed vessel storing lubricating oil; an electric-driving element; and a compressing element driven by the electric-driving element, the compressing element including: wherein a first oil groove is concavely formed on the outer circumference of the piston, and a second oil groove is concavely formed adjacent the first oil groove away from the compression chamber relative to the first oil groove, the second oil groove having a spatial volume not less than that of the first oil groove, wherein a uniform clearance portion where a clearance between the piston and the cylindrical hole portion is constant is provided in the cylindrical hole portion, so that the first oil groove is located at the uniform clearance portion when the piston is close to a top dead point, and an expanded clearance portion is provided to a side of the bottom dead end point relative to the uniform clearance portion, the expanded clearance portion being adjacent to the uniform clearance portion and broadening the clearance toward a bottom dead end point; and wherein a notched portion is further provided in the expanded clearance portion of the cylindrical hole portion, the first oil groove and the second oil groove being connected to inside the closed vessel via the notched portion when the piston is close to the bottom dead point.