Electric spindle bearing preloading device, electric spindle and machine tools

Abstract

The invention provides an electric mainshaft bearing pre-tightening device, an electric mainshaft and a machine tool. The electric mainshaft bearing pre-tightening device comprises a fixing piece, a pre-tightening piece, a spiral coil and a coil controller, and the coil controller is electrically connected with the spiral coil; the pre-tightening piece can move relative to the fixing piece in theaxial direction of the fixing piece, and in the axial direction of the fixing piece, the pre-tightening piece is provided with a bearing butting surface facing back to the fixing piece; and in the axial direction of the fixing piece, the spiral coil is arranged between the fixing piece and the pre-tightening piece, and the extending direction of the spiral coil is perpendicular to the axial direction of the fixing piece. The electric mainshaft comprises the electric mainshaft bearing pre-tightening device. The machine tool comprises the electric mainshaft. The spiral coil can expand in the radial direction after being electrified, the two radial ends of a spiraltron correspondingly abut against the fixing piece and the pre-tightening piece, the radial expansion of the spiral coil causes the change of the abutting force on the pre-tightening piece, and thus the change of the pre-tightening force on the outer ring of the bearing is caused. The pre-tightening force is proportional to theinput current of the spiral coil, the control accuracy of the pre-tightening force is high, and thus the electric mainshaft is effectively protected.

Description

technical field [0001] The invention relates to the technical field of machine tool equipment, in particular to an electric spindle bearing pretensioning device, an electric spindle and a machine tool. Background technique [0002] Processing equipment such as a machine tool has an electric spindle, and the electric spindle has a spindle body and an angular contact bearing located on the periphery of the spindle body. When the electric spindle rotates at high speed, the angular contact bearing is squeezed to the outer circumference by the centrifugal force, and the inner ring of the bearing expands, resulting in a decrease in the overall rigidity of the spindle body and more prone to bending deformation. Therefore, it is necessary to apply an axial preload to the outer ring of the bearing to resist Bearing deformation to protect the bearing and reduce bending deformation of the main shaft body. [0003] The invention patent with the notification number CN207857874U disclose...

AI Technical Summary

Problems solved by technology

[0004] The problem existing in this kind of electric spindle bearing stiffness control system is that the change of the spring force is relatively unstable, which leads to poor control accuracy of the pretightening force and poor protection effect on the electric spindle

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