Sealed compressor and refrigeration unit comprising sealed compressor

A sealed compressor comprising:

• an electric component including a stator and a rotor;
• a compression component actuated by the electric component;
• and
• a sealed container which accommodates the electric component and the compression component and stores lubricating oil therein,
• wherein the compression component includes
• a shaft including a main shaft section to which the rotor is fastened and an eccentric shaft section,
• a cylinder block having a compression chamber,
• a piston reciprocatable inside the compression chamber,
• a connecting member for coupling the piston to the eccentric shaft section,
• a main bearing unit mounted to the cylinder block and supporting the main shaft section such that the main shaft section is rotatable, and
• a thrust ball bearing mounted to a thrust surface of the main bearing unit,
• wherein the thrust ball bearing includes
• a plurality of balls held in a cage,
• an upper race having main surfaces one of which is in contact with upper portions of the balls, and
• a lower race having main surfaces one of which is in contact with lower portions of the balls,
• wherein the main shaft section is inserted in an inner periphery of the upper race, an upper main surface of the upper race is in contact with a flange surface, and a lower main surface of the upper race is above an upper end of a bearing extending section,
• wherein the bearing extending section is inserted in an inner periphery of the lower race and an inner periphery of the cage,
• wherein a first clearance is formed between an outer peripheral surface of the main shaft section and an inner peripheral surface of the upper race, the first clearance being a distance separating the outer peripheral surface of the main shaft section and the inner peripheral surface of the upper race in a radial direction before operation of the compressor,
• wherein a second clearance is formed between an outer peripheral surface of the bearing extending section and an inner peripheral surface of the cage, the second clearance being a distance separating the outer peripheral surface of the bearing extending section and the inner peripheral surface of the cage in the radial direction before operation of the compressor,
• wherein a third clearance is formed between the outer peripheral surface of the bearing extending section and an inner peripheral surface of the lower race, the third clearance being a distance separating the outer peripheral surface of the bearing extending section and the inner peripheral surface of the lower race in the radial direction before operation of the compressor,
• wherein raceway grooves formed by annular grooves are provided on the lower main surface of the upper race and the upper main surface of the lower race, respectively, the lower main surface of the upper race and the upper main surface of the lower race facing each other,
• wherein the balls are placed on the raceway groove of the upper race and the raceway groove of the lower race,
• wherein the first clearance is smaller than the second clearance and the third clearance,
• wherein the second clearance is greater than the third clearance, and
• wherein the first clearance, the second clearance, and the third clearance are arranged at an inner periphery of the thrust ball bearing.