Hermetic compressor
View Patent ↗A hermetic compressor includes: a main bearing ( 126 ) which supports a main shaft ( 120 ) of a shaft ( 119 ); and a thrust ball bearing at an upper end portion of the main bearing ( 126 ). A rotor ( 116 ) is fixed to the main shaft ( 120 ) via a flange. A rotor core ( 117 ) has a magnetic center displaced upward relative to the magnetic center of a stator core ( 115 ) so that a downward magnetic attractive force is applied between the rotor ( 116 ) and the stator ( 114 ). Accordingly, a contact load between steel balls and upper and lower races in the thrust ball bearing is appropriately maintained.
1. A hermetic compressor comprising:
a hermetic container for storing lubricating oil, the hermetic container including a motor element and a compression element disposed above the motor element,
wherein the motor element includes a stator and a rotor, the stator including a stator core and a winding, the rotor including a rotor core, a permanent magnet, and a flange which is disposed below the rotor core,
wherein the compression element includes:
a shaft having a main shaft and an eccentric shaft;
a cylinder block having a cylinder;
a piston reciprocatable in the cylinder;
a connection portion which connects the piston and the eccentric shaft;
a main bearing disposed in the cylinder block, the main bearing supporting the main shaft of the shaft; and
a thrust ball bearing disposed at an upper end portion of the main bearing, the thrust ball bearing including a plurality of steel balls, an upper race above the plurality of steel balls, and a lower race below the plurality of steel balls,
wherein the rotor is fixed to the main shaft via the flange, and
wherein the rotor core has a magnetic center displaced upward relative to a magnetic center of the stator core.
2. The hermetic compressor according to claim 1 ,
wherein the rotor core has a bottom at a position higher than a position of a bottom of the stator core.
3. The hermetic compressor according to claim 1 ,
wherein the flange has an outer diameter smaller than an outer diameter of the rotor core.
4. The hermetic compressor according to claim 1 ,
wherein the flange comprises a non-magnetic material.
5. The hermetic compressor according to claim 1 ,
wherein the main bearing extends into an inner diameter side of the rotor core and has a bottom closely facing a top surface of an upper portion of the flange.