Patent ID: 7631729

Claim:
A reciprocating compressor comprising: (a) a motor unit; (b) a compressing unit disposed over said motor unit and including: (b-1) a compression chamber; (b-2) a piston disposed for reciprocation in said compression chamber; and (b-3) a crankshaft rotatable about a rotation axis and configured to convert rotating action of said motor unit into reciprocating action of said piston; and (c) an enclosed container accommodating said motor unit and said compressing unit and having a lubricant oil pooling portion configured to pool lubricant oil, wherein said crankshaft includes: (b-3-1) a centrifugal pump disposed at a lower section of said crankshaft and opening into the lubricant oil pooling portion of said container; and (b-3-2) a pair of spiral pumps, functionally independent, disposed at a middle section of said crankshaft, fluidically connected with said centrifugal pump, and having leading grooves running in opposite directions to each other, wherein said spiral pumps respectively have upper ends and lower ends, and said centrifugal pump is fluidically connected with said spiral pumps only at said lower ends thereof via one communicating section, wherein a pair of vertical holes, functionally independent, are provided at an upper section of said crankshaft, said vertical holes respectively having upper ends and lower ends, said upper ends of said vertical holes opening into said container through an uppermost end surface of said crankshaft, said lower ends of said vertical holes being connected to said spiral pumps to fluidically connect said vertical holes with said spiral pumps, respectively, wherein said centrifugal pump includes a throttle section provided with a bottom wall having a suction hole, disposed in said lubricant oil pooling portion, for allowing the lubricant oil pooled in said container to be drawn into said centrifugal pump, said bottom wall being perpendicular to said rotation axis of said crankshaft, wherein said centrifugal pump further includes a hollow cylinder extending upward from a lower end of said crankshaft, wherein said suction hole has a diameter smaller than a diameter of said hollow cylinder, wherein said crankshaft comprises an eccentric shaft, and a main-shaft section provided under the eccentric shaft, wherein said hollow cylinder is inclined with respect to said rotation axis of said crankshaft, wherein a vent hole is provided at an upper section of said hollow cylinder, and wherein said vent hole is formed of a first part and a second part, said first part extends upwardly along said rotation axis of said crankshaft from an off-center position with respect to said rotation axis of said crankshaft at an upper section of said hollow cylinder, and said second part extends from an upper end of said first part to an upper opening that opens into said container and is located at an upper end of said main-shaft section.