Scroll Air Conditioning Compressor
The scroll compressor is a type of rotary positive-displacement compressor. It is currently the mainstream model for central air conditioning systems (3 HP and above), VRF (Variable Refrigerant Flow) systems, heat pumps, and thermal management systems in new energy vehicles. It compresses refrigerant through the meshing of a pair of involute scroll plates; lacking pistons, connecting rods, or suction valves, the compression process is continuous and smooth.
Core Structure
Fixed Scroll (Stationary Scroll): Mounted to the compressor housing; features a central discharge port and an outer suction port, with spiral teeth shaped as involutes.
Orbiting Scroll (Rotating Scroll): Positioned 180° out of phase with the fixed scroll and driven by an eccentric crankshaft; it performs an orbiting motion (revolution) but does not rotate on its own axis (no self-rotation).
Oldham Coupling (Anti-rotation Mechanism): Prevents the orbiting scroll from rotating on its own axis, ensuring it only performs small-radius planar orbital motion to maintain the meshing seal.
Eccentric crankshaft, built-in motor, back-pressure chamber, axial seal strip, refrigeration oil.
Function of the Back-pressure Chamber: Uses high-pressure discharge refrigerant to press the orbiting scroll against the face of the fixed scroll, automatically compensating for axial wear and maintaining sealing performance over the long term.
Detailed Working Principle
The meshing of the orbiting and fixed scrolls creates multiple crescent-shaped sealed chambers. With each full rotation of the main shaft, the processes of suction, compression, and discharge occur simultaneously and in parallel (unlike the intermittent compression found in piston compressors).
Suction Stage
As the orbiting scroll orbits, the volume of the outer crescent-shaped chamber gradually expands, creating negative pressure; low-temperature, low-pressure gaseous refrigerant is drawn in through the outer suction port and enters the outer base volume. Continuous suction occurs at the outer periphery.
Compression Stage
As the orbiting scroll continues its orbital motion, the sealed crescent chambers move from the outer periphery toward the center, and the chamber volume continuously shrinks; the refrigerant trapped within is compressed as its pressure and temperature gradually rise.
Characteristics: Multiple chambers compress simultaneously, resulting in a gradual pressure gradient and the absence of severe pressure surges.
