The invention discloses an 
air compression device of an electrical oil-free main 
air compressor, and belongs to the technical field of air compressors. The 
air compression device comprises a main housing, a 
crankshaft, a fan end bearing, a large counterweight block, a swinging rod bearing, a swinging rod, a small counterweight block, a motor end bearing, a coupler and a compression cylinder component; the compression cylinder component consists of a low-pressure cylinder cover, an output connector, a valve plate screw, an exhaust reed, a valve plate, an air inlet reed, a low-pressure cylinder body, a 
cushion block, a low-pressure cylinder sleeve, a 
piston ring, a supporting ring, a low-pressure 
piston, a connecting rod small end bearing, an oil seal, a 
piston pin, a heat insulation ring and a 
compression screw; the compression cylinder component consists of at least one high-pressure cylinder component and at least two low-pressure cylinder components; the 
piston ring and the supporting ring are made of teflon; the oil seal avoids leakage of bearing 
grease; the heat insulation ring insulates heat of the low-pressure piston. Oil leakage and blow-by hidden dangers of the air compressors are eliminated through 
air cooling, and a reasonable air flow trend is formed. With the adoption of the 
piston ring and the supporting ring that are made of teflon, no 
oil cooling is required, and the maintenance cost is reduced.