Abstract: When the air conditioner is opened, due to the material characteristics of the parts, the effect of thermal expansion and cold contraction will occur, and the parts will change in length and volume, especially in the air conditioner outlet position, the temperature difference is relatively large. When the parts undergo thermal expansion and contraction, the size of the parts will change and produce a certain displacement, resulting in the abnormal noise of “clicking” in the air conditioner. Through the analysis of abnormal noise, in the cooling and heating of air conditioning, the force of parts after deformation is unbalanced, and the dynamic friction force between parts is larger than the static friction force when thermal expansion and cold contraction occur, resulting in sliding friction and sound. In order to optimize and improve the abnormal noise of this kind of air conditioning structure, improved the force between the parts by optimizing the structure, so that the force balance between the parts after installation of the whole machine was achieved, so as to reduce the static friction between the parts and improve the stick-slip friction, so as to optimize the abnormal noise of the structure generated by the air conditioning. The noise experience of the whole machine was remarkable, and the noise test was qualified.

Key words: Extraordinary noise, Thermal expansion and contraction, Static friction force, Stick-slip friction