Compact Dry-Running Piston Compressor

Abstract

A compact dry-running piston compressor includes at least one cylinder for the compression of air by a corresponding piston, which may be driven by an electric motor with a crank drive made up of a crankshaft and connecting rod. The crank drive is rotatably mounted in an oil-bath-free compressor housing on pre-lubricated roller bearings and generates an internal cooling air flow inside the housing due to its movement cycle. The compressor housing includes two housing sections separated by a partition wall, in order to accommodate the crank drive within the first housing half and the electric motor in the second housing half. A roller bearing common to the crank drive and the electric motor is arranged in the partition wall lying in the cooling air flow passing through the first housing half.

1 . A compact dry-running piston compressor having at least one cylinder for compressing air via an associated piston, the compressor comprising:
 a crank drive including a crankshaft and connecting rod, the connecting rod being connectable with the piston;   an electric motor operatively configured to drive the associated piston via the crank drive;   an oil-bath-free housing comprising first and second housing sections separated by a partition, the crank drive being accommodated within the first housing section and the electric motor being accommodated within the second housing section; and   pre-lubricated roller bearings arranged in the housing for rotatably mounting the crank drive, one of said roller bearings being common to the crank drive and the electric motor and arranged in the partition, the one roller bearing being located in a cooling air flow generated by a movement cycle of the crank drive, which cooling air flow passes through the first housing section.   
   
   
       2 . The compact dry-running piston compressor according to  claim 1 , further comprising at least one opening provided in the partition, the at least one opening allowing at least a portion of the cooling air flow to be branched from the first housing half into the second housing half. 
   
   
       3 . The compact dry-running piston compressor according to  claim 1 , wherein the electric motor comprises a driven-side end winding, the driven-end side winding being concomitantly cooled via the one roller bearing located in the cooling air flow and via heat conduction of the partition. 
   
   
       4 . The compact dry-running piston compressor according to  claim 2 , wherein the electric motor comprises a driven-side end winding, the driven-end side winding being concomitantly cooled via the one roller bearing located in the cooling air flow and via heat conduction of the partition. 
   
   
       5 . The compact dry-running piston compressor according to  claim 1 , wherein a further roller bearing rotatably mounts the crankshaft, the further roller bearing arranged at another side of the crankshaft. 
   
   
       6 . The compact dry-running piston compressor according to  claim 5 , further comprising:
 a relatively flat cover operatively configured for closing the first housing section; and   wherein the further roller bearing is arranged in the cover so as to be encapsulated with respect to the area outside of the cover.   
   
   
       7 . The compact dry-running piston compressor according to  claim 5 , wherein the further roller bearing is also located in the cooling air flow passing through the first Musing section. 
   
   
       8 . The compact dry-running piston compressor according to  claim 5 , wherein a rotor of the electric motor is mounted in the housing via two roller bearings of the crankshaft. 
   
   
       9 . The compact dry-running piston compressor according to  claim 1 , wherein a rotor of the electric motor is attached directly to an end of the crankshaft, said end of the crankshaft projecting into the second housing section. 
   
   
       10 . The compact dry-running piston compressor according to  claim 1 , wherein the electric motor is a brushless direct-current motor having a stator composed of coil windings with an iron core and a rotor equipped with permanent magnets. 
   
   
       11 . The compact dry-running piston compressor according to  claim 1 , further comprising commutating electronics for controlling the electric motor, the commutating electronics being arranged on a printed circuit board accommodated in or on the second housing section. 
   
   
       12 . The compact dry-running piston compressor according to  claim 1 , further comprising a relatively flat cover for closing-off an end side of the second housing section. 
   
   
       13 . The compact dry-running piston compressor according to  claim 1 , wherein the first housing section includes an opening in which the cylinder, formed as a separate component, is releasably attached. 
   
   
       14 . The compact dry-running piston compressor according to  claim 1 , further comprising inflow ducts arranged in the compressor, the inflow ducts having varying cross-sections to provide different cooling air flows through individual assemblies of the compressor.