Patent ID: 7993114

Claim:
Electric compressor comprising: a single-phase induction motor comprising a stator and a rotor; a compressing mechanism driven by the motor; and a hermetic container for accommodating the motor and the compressing mechanism and for pooling lubricant, wherein the compressing mechanism includes: a shaft having a main shaft and a sub-shaft, the main shaft comprising a first section having a first diameter and a second section having a second diameter smaller than the first diameter; a cylinder for forming a compressing chamber; an annular lubricant groove having an inner rim and an outer rim; and a bearing for supporting the main shaft, the bearing defining in part the outer rim of the annular lubricant groove, wherein the shaft includes: a circumferential notch defining in part the inner rim of the annular lubricant groove, the circumferential notch having a lower axial surface; a centrifugal pump opening into the lubricant; a forward leading groove engraved on an outer wall of the main shaft, the forward leading groove extending to and opening at the lower axial surface of the circumferential notch, and the forward leading groove having a first end communicating with the centrifugal pump and a second end opening to the inner rim of the annular lubricant groove; a reverse leading groove having a lead directing in an opposite direction to that of the forward leading groove, the reverse leading groove extending to and opening at the lower axial surface of the circumferential notch, and the reverse leading groove having a first end communicating with the centrifugal pump via the second section of the shaft, and a second end opening to the inner rim of the annular lubricant groove; and a vertical hole bored in the sub-shaft and having a first end communicating with the outer rim of the annular lubricant groove, and a second end opening into the hermetic container, wherein the forward leading groove, the annular lubricant groove, and the vertical hole define a lubricant pathway such that (1) the lubricant passes from the forward leading groove to the annular lubricant groove, and (2) the lubricant passes from the annular lubricant groove to the vertical hole, and wherein the reverse leading groove has at least one of (1) a cross-sectional area smaller than that of the forward leading groove and (2) a lead greater than that of the forward leading groove.