Air distribution mechanism and cryogenic refrigerator using same

An air distribution mechanism, comprising an air distribution valve (6) comprising an air distribution side flow path and a rotary valve (7) comprising a switching side flow path, wherein the air distribution valve (6) comprises an air distribution valve main body (6a) and an air distribution valve seat (6b) that are fixedly connected and that are dismountable, an air distribution plane (6a3) that is on the air distribution valve main body (6a) and faces away from the air distribution valve seat (6b) protrudes relative to the air distribution valve seat (6b), the air distribution plane (6a3) is brought into contact with a switching plane (73) on the rotary valve (7), and the switching plane (73) protrudes from the rotary valve (7);

• the air distribution valve (6) is fixedly mounted in a mounting chamber of the cover (2), and the rotary valve (7) is rotatable around a principal rotation axis O of the rotary valve relative to the air distribution valve (6) to switch connection states of the air distribution side flow path of the air distribution valve (6) and the switching side flow path of the rotary valve (7);
• the air distribution valve main body (6a) and the air distribution valve seat (6b) are eccentrically and fixedly connected together by an intra-valve positioning pin (6c), the air distribution valve main body (6a) is provided with a main body pin hole (6a5) into which one end of the intra-valve positioning pin (6c) is inserted, and the air distribution valve seat (6b) is provided with a valve seat pin hole (6b5) into which the other end of the intra-valve positioning pin (6c) is inserted;
• and material hardness of the air distribution valve main body (6a) is lower than material hardness of the rotary valve (7).