Patent UA-102029-C2 (UA)
Title: Method of stabilizing radial position of axis of rotation of shaft of radial spindle bearing on permanent magnets
Inventor: HRYTSENKO VOLODYMYR ILLICH
IPC: B23B19/00
Filed: 2012-02-20
Abstract: The invention relates to machine-tool construction and can be used in designing high-precision machine tools for machining precision optical and mechanical elements. This is achieved by a method of stabilizing the radial position of the axis of rotation of a shaft of radial spindle bearing on permanent magnets, which includes measurement of the distance between the shaft of radial spindle bearing on permanent magnets and bases of values of gaps, definition of an nonshifted position of the axis of rotation of spindle bearing on permanent magnets, formation of arrays of reference values of gaps, generation of error signals on the power magnetic suspensions, according to the invention, the sensors of the values of gaps are set on the circumference of the inner surface of the housing of radial spindle bearing on permanent magnets in sections A-A and B-B of bearing along the axes of coordinate systems XOYand XOYon the outer sides of magnetic power pushers, whose origins lie on the axis of symmetry of the inner surface of the bearing housing followed by injection of control signals to the groups of in-parallel connected power magnetic pushers mounted in the bearing housing in sections C-C and D-D of bearing above the magnets of the spindle bearing shaft on the axes of coordinate systems XOYand XOY, whose axes are parallel to each other and parallel to the axes of the coordinate systems XOYand XOY, and under sensors of the values of gaps set on the axes of the same name of the coordinate systems XOYand XOYare set the equal values of gaps, the symmetry axis of the spindle bearing shaft on permanent magnets is aligned with the origin of coordinate systems XOYand XOY, the symmetry axis of shaft is taken as a geometric axis of rotation of the bearing shaft followed by calculation of the repulsive force between the groups of power magnetic pushers established on the axes of the same name of the coordinate systems XOYand XOY, and magnets of the bearing shaft for a given value of displacement of the bearing shaft on these axes and calculation of the stiffness of radial spindle bearing on permanent magnets, calculation of the critical angular velocity of a chuck and bearing shaft, the shaft of radial spindle bearing on permanent magnets is mounted at the rotation angle φ = 0 followed by N times measurement of the value of gaps under sensors of gap sizes mounted on the semiaxes +X,+Y,+X,+Yof the coordinate systems XOYand XOYand calculation of their asymptotically unshifted estimates, position of the geometrical axis of rotation of the bearing shaft, at which on the angle φ = 0 of rotation of the bearing shaft of the value of gaps under the sensors of the values of gaps are equal to measured values is taken as unshifted position, the bearing shaft is given a rotational speed ωsatisfying the inequalities ω<ωi ωω,, on the angle φ = 0 of the shaft rotation for N times at N shaft speed is measured the values of gaps under the sensors of gap sizes mounted on the semiaxes +X,+Y,+X,+Yof coordinate systems XOYand XOYfollowed by calculation of their asymptotically unshifted estimates, then it is calculated the value of displacement of the geometrical axis of shaft rotation under dynamic loading in the planes of mounting the sensors of gap sizes on the axes of coordinate systems XOYand XOYand the displacement of the values of displacement of geometrical axis of rotation of the shaft under the action of the coordinate systems XOYand XOYand then the values are calculated of displacement of the geometrical axis of rotation of the shaft and tilt angles of vectors of the dynamic load on the bearing shaft to the axes Xand Xof the coordinate systems X0Yand XOY, on the angular velocity ω, then the bearing shaft is balanced and the values of gaps, which provide at least minimum rate of differences are set under the sensors of gap sizes established on the semiaxes +X,+Y,+X,+Yof coordinate systems XOY   and the geometric axis of rotation of the shaft is approached to its displaced position or placed it in the unshifted position, if the rate differences is equal to zero, if the rate differences is not equal to zero with a step Δω the angular velocity of rotation of the bearing shaft is increased, at each step of increasing the speed of rotation the bearing shaft is balanced, after balancing the shaft at k-th step of increasing the angular velocity of rotation of the shaft on the rotation angle φ = 0 for N times at N rotations of the shaft the values are measured of gaps under the sensors of gap sizes set on the semiaxes +X,+Y,+X,+ Yof coordinate systems XOYand XOYfollowed by calculation of the rate of differences, if the rate of differences rate approaches zero, the shaft of radial spindle bearing on permanent magnets is balanced with high accuracy, the bearing shaft is set in working speed of rotation, at each discrete rotation angle of the bearing shaft φ + 0, φ=Δφ, φ=2Δφ,...,φ=kΔφ,...,φ=360° -Δφ for N times at N shaft speed the gap sizes are measured under the sensors of gap sizes installed on semiaxes +X,+Y,+X+Yof thecoordinate systems XOYand XOYfollowed by calculation of their asymptotically unshifted estimates that are taken as values of reference gaps corresponding to the unshifted position of the axis of rotation of the bearing shaft, during stabilization process of the radial position of the axis of rotation of the shaft of the radial spindle bearing on permanent magnets the current values ​​of gaps under the sensors of gap sizes installed on the semiaxes +X,+Y,+X,+Yof coordinate systems XOYand XOYon the increments of the angle of rotation of the bearing shaft are compared with the values ​​of respective reference gaps, in case of deviation of current values of gaps from the reference value the error signals are generated on respective groups of power magnetic pushers corresponding to the deviation values of current values of gaps from reference values that prevents the deviation of the axis of rotation of the shaft of spindle bearing on permanent magnets from the unshifted position,where:- asymptotically unshifted estimates under the sensors of gap sizes mounted on the semiaxes +X+Y,+X,+Yof coordinate systems XOYand XOYon the angle of φ-0 of the shaft rotation at ω=0; - asymptotically unshifted estimates of gap sizes under the sensors of gap sizes installed on semiaxes +X,+Y+X,+Yof coordinate systems XOYand XOYon the angle of shaft rotation at ω=ω.