Gas compressor volute assembly adopting arc outlet diffusion cavity

The invention discloses a gas compressor volute assembly adopting an arc outlet diffusion cavity. The assembly comprises a gas compressor volute and a gas compressor back disc; the volute diffusion wall face of the gas compressor volute is round, the lower end of the volute is a plane, the upper end of the volute is a volute diffusion arc wall face, and the volute diffusion arc wall face of the upper end and the plane of the lower plane are in circular-arc transition; the back disc diffusion wall face of the gas compressor back disc is round, the lower end of the gas compressor back disc is a plane, the upper end of the gas compressor back disc is a back disc diffusion arc wall face, and the back disc diffusion arc wall face at the upper end and the plane at the lower end are in circular-arc transition. The gas compressor back disc is fixed to the gas compressor volute through a pressing plate and a screw, and the diffusion cavity with an arc air outlet is formed between the volute diffusion wall face and the back disc diffusion wall face; the arc shape and the arc size of the arc air outlet are obtained through the gas compressor characteristic test or CAE gas compressor characteristic calculation, and the shape and the size are optimum with the air flowing loss in the gas compressor being minimum, namely the efficiency of the gas compressor being the best.