Bearing preloading method for main shaft of bed head box with large through hole

Abstract

The invention relates to a machine tool mounting technology, in particular to a bearing pre-tightening method for a large-through-hole headstock mandrel. The method comprises the following steps that(S1) the axial displacement difference delta H1 of a bearing inner ring of a front bearing under the working conditions that the load exists and no load exists is measured; (S2) the axial displacementdifference delta H2 of a bearing inner ring of a rear bearing under the working conditions that the load exists and no load exists is measured; and (S3) the front bearing and the rear bearing are pre-tightened and assembled to the front end and the rear end of the mandrel respectively, and it is guaranteed that before and after pre-tightening, the axial displacement difference of the bearing inner ring of the front bearing is delta H1 and the axial displacement difference of the bearing inner ring of the rear bearing is delta H2. According to the method, the pre-tightening force on the bearings of the large-through-hole mandrel is effectively adjusted, and especially under the heavy load condition, the mandrel precision is stable and reliable.

Description

technical field [0001] The invention relates to machine tool installation technology, in particular to a bearing pre-tightening method for a headstock main shaft with a large through hole. Background technique [0002] In the assembly of the main shaft of the headstock of the large through-hole machine tool, because the workpiece passes through the main shaft hole, the inner hole of the main shaft is relatively large, and the bearing used to fix the main shaft is also enlarged. In order to prevent the unbalanced torque generated by the gap between the inner and outer rings of the bearing when the main shaft rotates, which will affect the stability and rotation accuracy of the main shaft rotation, refer to figure 1 with figure 2 , Double-row cylindrical roller bearings (such as NNU4984K P5) are often used to control the radial runout of the main shaft, and double-row tapered roller bearings (such as 351984 P5) are used to limit the axial movement of the main shaft, so as to...

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