Patent ID: 7033662

Claim:
A knob fitting structure comprising: a knob; an operation shaft to which the knob is to be fitted; an engaging stub provided on one of the knob and the operation shaft; and a supporting side wall having a snap-in hole with a slit communicating with outside through the snap-in hole provided on the other of the knob and the operation shaft, wherein the engaging stub elastically deforms the supporting side wall in a direction of thickness of the engaging stub when the engaging stub is inserted into the snap-in hole, and said supporting side wall is in an essentially undeformed condition subsequent to the insertion of the engaging stub; the operation shaft is prismatically shaped, the knob is provided with a pair of supporting side walls arranged opposite each other with some space between the pair of supporting side walls and a pair of linking side walls arranged opposite each other and linking side edges of the pair of supporting side walls extending in an axial direction of the operation shaft to each other, wherein the pair of supporting side walls and the pair of linking side walls are formed to surround on four sides, and wherein the prismatically shaped operation shaft is arranged between the pair of supporting side walls and the pair of linking side walls surrounding the operation shaft on four sides.