Noise suppressing mechanism in piston-type compressor

A compressor comprising a housing body, a drive shaft rotatably supported in the housing body, a drive plate mounted on the drive shaft, at least one cylinder bore defined in the housing body and a piston operably coupled to the drive plate and disposed in the cylinder bore, wherein said drive plate converts rotation of the drive shaft to reciprocating movement of the piston in the cylinder bore to compress gas supplied from a suction chamber to the cylinder bore and discharge the compressed gas to a discharge chamber, axial force acting on the piston due to the reciprocating movement of the piston;

• the housing body including a cylinder block containing the cylinder bore and a housing member coupled to the cylinder block to define the discharge chamber, said cylinder block having an inner surface, and
• said drive plate having a boss portion, said boss portion having an end face opposing said inner surface of the cylinder block;
• at least one thrust bearing disposed between the end face of the boss portion and the inner surface of the cylinder block for applying an axial preload to the drive shaft;
• and
• means for applying a force to minimize displacement of the drive shaft in the axial direction thereof in accordance with said axial force acting on the piston.

A compressor for use in a vehicle, the compressor comprising a housing body, a drive shaft rotatably supported in the housing body, a drive plate mounted on the drive shaft, at least one cylinder bore defined in the housing body and a piston operably coupled to the drive plate and disposed in the cylinder bore, wherein said drive plate converts rotation of the drive shaft to reciprocating movement of the piston in the cylinder bore to compress gas supplied from a suction chamber to the cylinder bore and discharge the compressed gas to a discharge chamber, axial force acting on the piston due to the reciprocating movement of the piston,

• said housing body including:
• a front cylinder block and a rear cylinder block coupled to each other, said front cylinder block and said rear cylinder block respectively containing one of at least one pair of opposing coaxial cylinder bores, wherein each pair of said opposing cylinder bores contains a piston having a front head and a rear head, with the cylinder bores in the front cylinder block containing said front heads and the cylinder bores in the rear cylinder block containing said rear heads;
• a front housing coupled to a front end of the front cylinder block;
• and
• a rear housing coupled to a rear end of the rear cylinder block,
• wherein each of said housings define a discharge chamber for the cylinder bores in the adjacent cylinder block;
• said front cylinder block and said rear cylinder block respectively having opposing inner surfaces;
• said drive plate having a boss portion having a pair of end faces each opposing a respective one of the inner surfaces of the front cylinder block and the rear cylinder block;
• said compressor further comprising a pair of thrust bearings, each thrust bearing being disposed between a respective one of said end faces of the boss portion and a respective one of the inner surface of the front cylinder block and the rear cylinder block for applying an axial preload to the drive shaft;
• means for applying a force in accordance with said axial force acting on the piston;
• and
• said force applying means including means for biasing the thrust bearings in the axial direction of the drive shaft to substantially cancel the force caused by the reciprocating movement of the piston and acting on the drive shaft, wherein said biasing means increases biasing force in accordance with an increase of the pressure in the discharge chamber.