Lubricating mechanism and method for a piston assembly of a slant plate type compressor

In a refrigerant compressor including a compressor housing, said compressor housing including a cylinder block, a front end plate disposed on one end of said cylinder block, a rear end plate disposed on an opposite end of said cylinder block, said rear end plate having a discharge chamber and a suction chamber formed therein, said cylinder block having a plurality of cylinders formed therein, a crank chamber disposed forwardly of said plurality of cylinders and enclosed within said cylinder block by said front end plate, a piston slidably fitted within each of said cylinders, a piston chamber defined by each of said pistons and said cylinders, said pistons reciprocated by a drive mechanism, said drive mechanism including a drive shaft extending through an opening in said front end plate and rotatably supported therein, a drive rotor fixedly attached to and rotatable with said drive shaft, a slant plate attached to said drive rotor and disposed around said drive shaft and a wobble plate disposed on said slant plate and linked to said pistons through a connecting rod to reciprocate said pistons in said cylinders, said connecting rod including a ball portion formed at its one end, said piston including a spherical concavity formed at its bottom end to firmly receive said ball portion of said connecting rod while allowing said ball portion of said connecting rod to slidably move along an inner surface of said spherical concavity, at least one annular groove being provided on the outer peripheral surface of each of said pistons, at least one piston ring disposed within said at least one annular groove having an outer diameter larger than the outer diameter of said piston at normal temperatures, the improvement comprising:

• at least one conduit forming a fluid communication path between a bottom surface of said at least one annular groove and the inner surface of said spherical concavity, and a throttling means formed in said at least one conduit.

In a refrigerant compressor including a compressor housing, said compressor housing including a cylinder block, a front end plate disposed on one end of said cylinder block, a rear end plate disposed on an opposite end of said cylinder block, said rear end plate having a discharge chamber and a suction chamber formed therein, said cylinder block having a plurality of cylinders formed therein, a crank chamber disposed forwardly of said plurality of cylinders and enclosed within said cylinder block by said front end plate, a piston slidably fitted within each of said cylinders, a piston chamber defined by each of said pistons and said cylinders, said pistons reciprocated by a drive mechanism, said drive mechanism including a drive shaft extending through an opening in said front end plate and rotatably supported therein, a drive rotor fixedly attached to and rotatable with said drive shaft, a slant plate attached to said drive rotor and disposed around said drive shaft and a wobble plate disposed on said slant plate and linked to said pistons through a connecting rod to reciprocate said pistons in said cylinders, said connecting rod including a ball portion formed at its one end, said piston including a spherical concavity formed at its bottom end to firmly receive said ball portion of said connecting rod while allowing said ball portion of said connecting rod to slidably move along an inner surface of said spherical concavity, at least one annular groove being provided on the outer peripheral surface of each of said pistons, at least one piston ring disposed within said at least one annular groove having an outer diameter larger than the outer diameter of said piston at normal temperatures, the improvement comprising:

• means for throttling the piston chamber pressure, and means for lubricating said spherical concavity with said throttled piston chamber pressure,
• wherein said lubricating means comprises at least one conduit having said throttling means formed therein, one end of said conduit being open to a bottom surface of said at least one annular groove of each of said pistons and the other end of said conduit being open to the inner surface of said spherical concavity.

A method of supplying lubrication to a ball and socket joint in a piston and cylinder assembly of a refrigerant compressor including a suction chamber, crank chamber and discharge chamber comprising the steps of:

• compressing a refrigerant,
• collecting lubricating oil from the cylinder during said compression,
• throttling said compressed refrigerant and lubricating oil to reduce the pressure of said compressed refrigerant and lubricating oil, and
• delivering said throttled refrigerant and lubricating oil to said ball and socket joint.

In a refrigerant compressor including a compressor housing, said compressor housing including a cylinder block, a front end plate disposed on one end of said cylinder block, a rear end plate disposed on an opposite end of said cylinder block, said rear end plate having a discharge chamber and a suction chamber formed therein, said cylinder block having a plurality of cylinders formed therein, a crank chamber disposed forwardly of said plurality of cylinders and enclosed within said cylinder block by said front end plate, a piston slidably fitted within each of said cylinders, a piston chamber defined by each of said pistons and said cylinders, said pistons reciprocated by a drive mechanism, said drive mechanism including a drive shaft extending through an opening in said front end plate and rotatably supported therein, a drive rotor fixedly attached to and rotatable with said drive shaft, a slant plate attached to said drive rotor and disposed around said drive shaft and a wobble plate disposed on said slant plate and linked to said pistons through a connecting rod to reciprocate said pistons in said cylinders, said connecting rod including a ball portion formed at its one end, said piston including a spherical concavity formed at its bottom end to firmly receive said ball portion of said connecting rod while allowing said ball portion of said connecting rod to slidably move along an inner surface of said spherical concavity, at least one annular groove being provided on the outer peripheral surface of each of said pistons, at least one piston ring disposed within said at least one annular groove having an outer diameter larger than the outer diameter of said piston at normal temperatures, the improvement comprising:

• means for throttling the piston chamber pressure, and means for lubricating said spherical concavity with said throttled piston chamber pressure,
• wherein said lubricating means comprises at least one conduit formed in each of said pistons, one end of said conduit being open to the outer peripheral surface of each of said pistons, said one end of said conduit disposed on the crank chamber side with respect to said at least one groove, and the other end of said conduit opening into said spherical concavity.

A method of supplying lubrication to a ball and socket joint in a piston and cylinder assembly of a refrigerant compressor including a suction chamber, crank chamber and discharge chamber, said method comprising the steps of:

• compressing a refrigerant,
• collecting lubricating oil from the cylinder during said compression,
• throttling said compressed refrigerant and lubricating oil to reduce the pressure of said compressed refrigerant and lubricating oil, and
• delivering said throttled refrigerant and lubricating oil to said ball and socket joint,
• wherein said throttling step comprises the step of flowing said compressed refrigerant and lubricating oil through a small diameter portion of a conduit which is disposed in the piston.