| 摘要 |
PURPOSE:To prevent the work surface of a workpiece and hearings from respective failure in accuracy and rigidity and seizure due to temperature rising by making the body section inside of both the ends of the bearing mechanism of a spindle out of lower thermal expansion coefficient glass and a spindle head and the bearing mechanism out of low thermal expansion coefficient cost iron. CONSTITUTION:Neoceram used as material for a spindle body section 31 being extremely small in comparison with conventionally used irony material in a thermal expansion coefficient, the thermal displacement of the lower end of the body section 31 in relation to thrust bearing sections 22b and 23a determining the axial directional position of the body section 31 becomes extremely small. And the LE cast irony used as material for a spindle head 12 and bearing metals 21 thru 23 supported by a bed through column 11 is so small in comparison with ordinary cost iron or gun metal in a thermal expansion coefficient that the thermal displacement of the thrust bearing sections 22b and 23a in relation to the bed is also small. Even if the temperature of a spindle 30 is raised due to the rotation, therefore, the thermal displacement in relation to the bed of the lower end of the body section 31 to which a grinding wheel G is attached becomes extremely small preventing a workpiece W from failling the accuracy of the work surface. |
