Numerical control grinding machine motorized spindle capable of automatically adjusting bearing pretightening force

Abstract

The invention discloses a numerical control grinding machine motorized spindle capable of automatically adjusting bearing pretightening force. Specific to loss heating of a stator and a rotor of a motorized spindle, a dual water cold structure is designed; through two layers of cooling water sets at inside and outside of the shell body, the high-efficient radiation of a rotor is realized, the influence of the heating high temperature of the stator and the rotor on the spindle and the bearing is reduced; specific to the friction heating of the bearing itself, an outer bearing ring fixing sleeveis designed to be a cooling water sleeve structure; the high-efficient radiation of the bearing is realized through the bearing outer ring fixing sleeve with water cooling function, and then the bearing is efficiently lubricated to reduce the thermal deformation of the bearing; however, the cooling and lubricating effects can be reduced under the condition of higher rotate speed, thus the bearingmust be applied with proper pretightening force to counteract the thermal deformation; firstly, the bearing temperature is monitored in real time through a temperature sensor of an automatic bearingpretightening force adjusting mechanism, and the monitored bearing temperature data is fed back to a grinding machine numerical control system, and a control signal is output through the grinding machine numerical control system; thus elongation of a piezoelectric ceramic pillar is changed to generate proper pretightening force of the bearing.

Description

technical field [0001] The invention belongs to the technical field of machine tool electric spindles, in particular to a numerically controlled grinder electric spindle with automatic adjustment of bearing pretightening force. Background technique [0002] In recent years, more and more CNC grinding machines have adopted electric spindles. Electric spindles have the advantages of compact structure, light weight, small inertia, low noise, fast response, high speed and high power. Electric spindles are the combination of grinding machine spindles and spindle motors. The new technology of integration, and this kind of transmission structure that combines the grinding machine spindle and the spindle motor "into one", effectively makes the spindle components relatively independent from the transmission system and the overall structure of the grinding machine, while the grinding machine spindle is built. It is directly driven by an electric motor, so that the length of the main d...

AI Technical Summary

Problems solved by technology

The running accuracy of the electric spindle is determined by many factors, one of which is the pretightening force of the bearing. As the core component of the electric spindle, the bearing pretightening force not only determines the performance and life of the bearing, but also affects The vibration amplitude of the shaft end of the electric spindle, as the processing conditions change, the temperature of the bearing may rise rapidly, resulting in thermal deformation of the bearing, and the support accuracy of the bearing will also change accordingly. In order to reduce the variation range of the bearing support accuracy , the usual method is to provide preload through the spring, but due to the limitation of the spring output preload mode, the preload output by the spring cannot be adjusted. Since the bearing preload cannot be adjusted, it is impossible to pass a suitable preload. force to deal with thermal deformation of bearings

Therefore, at this stage, the CNC grinding machine electric spindle that uses springs as pre-tightening force application parts generally has the situation that the higher the speed is, the lower the machining accuracy is, which seriously restricts the high-speed development of CNC grinding machines.

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