Patent ID: 8206068
Filing Date: 2012-06-26
Classification: B23Q,Y10T

Abstract:
1. A main spindle device comprising: a housing; a main spindle that is inserted into the housing and supported by a bearing so as to be able to rotate relative to the housing, wherein a labyrinth-forming annular groove is formed, in a circumferential direction of the main spindle, on a protruding portion of the main spindle that protrudes from the housing on a front side along a rotation axis of the main spindle; and a housing lid member having a convex portion that is inserted, along a radial direction of the main spindle, into the labyrinth-forming annular groove so as not to contact an inside surface of the labyrinth-forming annular groove all around the periphery, the housing lid member being fixed to the housing on the front side thereof with the convex portion being inserted in the labyrinth-forming annular groove, wherein a gap between the convex portion and the labyrinth-forming annular groove forms a labyrinth seal portion, and the housing lid member is constructed so that the housing lid member can be divided into at least two pieces with respect to a circumference of the labyrinth-forming annular groove.