Abstract: In order to ensure the positioning accuracy of the motion mechanism in the air conditioner and meet the requirements of refined design and reliability, two different positioning schemes for the motion mechanism of the cabinet air conditioner were designed in the product design stage. By means of tolerance statistics and dimensional chain calculation, the tolerance and the unqualified rate of the closed ring size of the kinematic mechanism caused by the two positioning modes are compared and analyzed. The results show that the positioning datum designed in the middle of the panel seat has the advantages of short dimension chain, small tolerance and low unqualified rate, which is an effective way to improve the positioning accuracy and operation stability. Tolerance and dimensional chain calculation can be used to guide the positioning design of key features in the structural design stage of air conditioning, improve design efficiency with lower cost, and develop high-quality products.

Key words: Air conditioning design, Motion mechanism, Tolerance analysis, Dimensional chain analysis