Mechanical seal with embedded lubrication

#The present invention relates to a mechanical seal, and more particularly to a mechanical seal disposed between two relatively moving bearing surfaces such as, for example, between a rotating bearing surface and an associated stationary bearing surface for providing a seal around the drive shaft of a variable displacement swash plate type compressor used in an air conditioning system for a vehicle.

#A mechanical face seal is frequently used in an automotive cooling pump or refrigeration compressor. Generally, such seals include a stationary annular bearing surface integral with the compressor housing and an associated sealing ring disposed on a rotating drive shaft. A means are provided for urging the facing surfaces of the stationary bearing surface and the sealing ring together. The rotating surface of the sealing ring contacts the stationary bearing surface to form a sealing face which is perpendicular to the shaft. The stationary sealing surface is typically formed of cast iron, stainless steel, ceramic, hard chromium-plated steel or hardened bearing steel; and the associated rotating ring is formed of sintered carbon-graphite, resin-bonded carbon-graphite, resin impregnated carbon-graphite or ceramic.

#Refrigeration compressors are used to compress refrigerants, such as carbon dioxide, as part of a standard vapor-compression refrigeration cycle. Typically, a gaseous refrigerant is mixed with a liquid lubricating medium, such as oil, before entering the compressor. The oil is employed to lubricate the compressor components, such as bearings and seals, to reduce component wear. Refrigeration compressors typically include a shaft rotatably supported by bearings within a compressor housing. Mechanical seals are typically employed in such refrigeration compressors to inhibit leakage of lubricating oil between the compressor housing and the shaft.

#The above, as well as other objects, features, and advantages of the present invention will be understood from the following detailed description of the preferred embodiment of the present invention with reference to the accompanying drawings, in which:

#FIG. 1 is a cross sectional elevational view of a variable displacement swash plate type compressor provided with a mechanical seal according to the present invention;

#FIG. 2 is a fragmentary enlarged cross sectional view of the compressor illustrated in FIG. 1, showing the features of the mechanical seal;

#Referring now to the drawings, and particularly FIG. 1, there is shown generally at 10 a variable displacement swash plate type compressor mounted with a mechanical seal 11, illustrated in detail in FIG. 2. The compressor 10 includes a cylinder block 12 having a plurality of cylinders 14. A cylinder head 16 is disposed adjacent one end of the cylinder block 12 and sealingly closes the end of the cylinder block 12. A valve plate 18 is disposed between the cylinder block 12 and the cylinder head 16. A crankcase 20 is sealingly disposed at the other end of the cylinder block 12. The crankcase 20 and cylinder block 12 cooperate to form an airtight crank chamber 22.

#The cylinder head 16 includes a suction chamber 24 and a discharge chamber 26. A suitable conduit is disposed to provide fluid communication between the crank chamber 22 and the suction chamber 24. An electronic control valve 28 is disposed in the conduit for controlling the flow of refrigerant gas from the crank chamber 22 to the suction chamber 24. The valve 28 can be of any conventional type such as, for example, a ball type valve. The valve 28 is designed to receive an electrical control signal from a remote microprocessor (not shown). The microprocessor monitors the discharge pressure of the compressor, the RPM of the vehicle engine, the cabin temperature and humidity, and the like, to control the valve 28 which, in turn, controls the flow of refrigerant gas from the crank chamber 22 to the suction chamber 24. An inlet port 30 provides fluid communication between an evaporator (not shown) of the cooling portion of an air conditioning system for a vehicle and the suction chamber 24. An outlet conduit 32 provides fluid communication between the discharge chamber 26 and the cooling portion of the air conditioning system for a vehicle. An oil separator 34 is disposed in the conduit 32. An orifice tube 36 provides fluid communication between the oil separator 34 and the crank chamber 22.

#Suction ports 38 provide fluid communication between the suction chamber 24 and each cylinder 14. Discharge ports 40 provide fluid communication between each cylinder 14 and the discharge chamber 26.