Magnetic drive coupling apparatus

#Aspects of the invention are directed to a magnetic drive coupling apparatus.

#Reciprocating and other types of compressors often have an open drive configuration whereby a compressor is coupled to a motor or engine. In such cases, the crankshaft of the compressor has a mechanical face seal, which seals refrigerant and other fluids in the interior of the compressor but also allows for the coupling to the motor or engine. The face seal operates with a film of oil between a stationary stator and the rotor, which rotates with the crankshaft. Due to the nature of the seal, however, it has been observed that oil tends to leak and drip outside of the sealed compressor. This causes complaints in the field and leads to the need for rework of compressors.

#A magnetic drive coupling apparatus is provided and includes a drive unit having a first rotatable shaft and an open drive assembly, a driven unit having an end face and a second rotatable shaft extending through the end face axially overlap, a magnetic drive coupling having first and second magnetically attractive parts associated with the first and second rotatable shafts, respectively, which transmits rotation between the first and second rotatable shafts and a sealing unit coupled to the end face to encompass the second magnetically attractive part and to hermetically seal oil and refrigerant in an interior of the driven unit.

#The subject matter which is regarded as the invention is particularly pointed out and distinctly claimed in the claims at the conclusion of the specification. The foregoing and other features, and advantages of the invention are apparent from the following detailed description taken in conjunction with the accompanying drawings in which:

#FIG. 1 is an enlarged side view of a compressor coupled to an engine; and

#FIG. 2 is a cutaway side view of a magnetic drive coupling between the compressor and the engine.

#Aspects of the invention eliminate the face seal of conventional configurations and instead employ a sealed magnetic drive coupling. The magnetic drive coupling has a hermetically sealed pressure barrier between a refrigerant side thereof and an atmospheric side thereof. Magnets are used to provide torque from an engine or other drive source (i.e., electric or hydraulic motors) to a compressor through the pressure barrier. A drive pulley may be combined with one half of the magnetic drive coupling. Elimination of the face seal creates a hermetically sealed open drive compressor that does not suffer from oil and/or refrigerant leaks and related repair costs.

#With reference to FIGS. 1 and 2, a magnetic drive coupling apparatus 10 is provided. The magnetic drive coupling apparatus 10 includes a drive unit 20, such as an engine or a motor, having a first rotatable shaft 25, an outer drive coupling 30 that is exposed to atmospheric conditions, is rotatable with the first rotatable shaft 25 and has a fan pulley 35, a driven unit 40, such as a compressor, having an end face 41 and a second rotatable shaft 45 extending axially through the end face 41, a magnetic drive coupling 50 and a sealing unit 60. The magnetic drive coupling 50 has first and second magnetically attractive parts 51 and 52, which are rotatably associated with the first and second rotatable shafts 25 and 45, respectively. The magnetic drive coupling 50 is thus configured to transmit rotation of the first rotatable shaft 25 to the second rotatable shaft 45 and vice versa in some cases. The sealing unit 60 is coupled to the end face 41 and configured to encompass at least the second magnetically attractive part 52 and to prevent leakage of fluid, such as oil and/or refrigerant, from an interior of the driven unit 40.

#The magnetic drive coupling 10 may further include a partial housing 70, which is mounted to the drive unit 20 at a first side thereof and the driven unit 40 at a second side thereof. The housing 70 does not encompass the magnetic drive coupling 50 so that the outer drive coupling 30 is exposed to the atmospheric conditions and so that the fan pulley 35 can be connectable with a fan pulley assembly, such as a fan belt and a secondary drive shaft for, e.g., a fan. The housing 70 increases stability of a connection between the drive unit 20 and the driven unit 40.