Stiffness gain mechanism for magnetic suspension bearing, magnetic suspension bearing, and blood pump

An active magnetic suspension bearing comprising a stiffness enhancing mechanism, a stator, and a rotor disposed within the stator, wherein the rotor comprises an upper surface and a lower surface that are perpendicular to an axis of rotation and a circumferential outer peripheral surface that is around the axis of rotation, and wherein the rotor is rotatable about the axis of rotation and the stator comprises a plurality of stator teeth spaced apart from each other in a circumferential direction, wherein each stator tooth of the plurality of stator teeth is provided with a magnetic suspension coil for suspending the rotor and controlling the movement of the rotor in a radial direction, and a gap exists between each stator tooth and the rotor, and wherein the stiffness enhancing mechanism is configured to control a degree of freedom of torsion about the radial direction of the rotor and comprises:

• a rotor permanent magnet fixed to the lower surface of the rotor that is perpendicular to the axis of rotation, wherein the rotor permanent magnet is parallel to a main plane of the rotor and abuts against the rotor, wherein the main plane of the rotor is a plane of symmetry of the rotor that extends perpendicular to the axis of rotation of the rotor;
• a stator permanent magnet arranged underneath horizontal portions of the plurality of stator teeth of the stator and on lower surfaces of the horizontal portions of the plurality of stator teeth of the stator, wherein the stator permanent magnet is parallel to the main plane of the rotor and abuts against the stator teeth of the stator, wherein a side where the stator permanent magnet is located is the same as a side where the rotor permanent magnet is located, and the stator permanent magnet is spaced apart from the rotor permanent magnet by a distance in the radial direction;
• and
• an axial driving body arranged to face the rotor permanent magnet and be spaced apart from the rotor permanent magnet by a distance in an axial direction;
• wherein the rotor permanent magnet and the rotor form a rotor assembly, and the rotor assembly has an asymmetric structure with respect to the main plane of the rotor;
• wherein the stiffness enhancing mechanism is configured such that the stator permanent magnet generates a radial attractive force to the rotor permanent magnet and the axial driving body generates an axial repulsive force to the rotor permanent magnet, wherein a torsional stiffness of the rotor is enhanced through a combined action of the radial attractive force and the axial repulsive force, and wherein a magnitude of the axial repulsive force is capable of decreasing when an axial distance between the axial driving body and the rotor permanent magnet increases, and the magnitude of the axial repulsive force is capable of increasing when the axial distance between the axial driving body and the rotor permanent magnet decreases.

A blood pump comprising an active magnetic suspension bearing, wherein the active magnetic suspension bearing comprises a stiffness enhancing mechanism, a stator, and a rotor disposed within the stator, wherein the rotor comprises an upper surface and a lower surface that are perpendicular to an axis of rotation and a circumferential outer peripheral surface that is around the axis of rotation, and wherein the rotor is rotatable about the axis of rotation and the stator comprises a plurality of stator teeth spaced apart from each other in a circumferential direction, wherein each stator tooth of the plurality of stator teeth is provided with a magnetic suspension coil for suspending the rotor and controlling the movement of the rotor in a radial direction, and a gap exists between each stator tooth and the rotor, and wherein the stiffness enhancing mechanism is configured to control a degree of freedom of torsion about the radial direction of the rotor and comprises:

• a rotor permanent magnet fixed to the lower surface of the rotor that is perpendicular to the axis of rotation, wherein the rotor permanent magnet is parallel to a main plane of the rotor and abuts against the rotor, wherein the main plane of the rotor is a plane of symmetry of the rotor that extends perpendicular to the axis of rotation of the rotor;
• a stator permanent magnet arranged underneath horizontal portions of the plurality of stator teeth of the stator and on lower surfaces of the horizontal portions of the plurality of the stator teeth of the stator, wherein the stator permanent magnet is parallel to the main plane of the rotor and abuts against the stator teeth of the stator, wherein a side where the stator permanent magnet is located is the same as a side where the rotor permanent magnet is located, and the stator permanent magnet is spaced apart from the rotor permanent magnet by a distance in the radial direction;
• and
• an axial driving body arranged to face the rotor permanent magnet and be spaced apart from the rotor permanent magnet by a distance in an axial direction;
• wherein the rotor permanent magnet and the rotor form a rotor assembly, and the rotor assembly has an asymmetric structure with respect to the main plane of the rotor;
• wherein the stiffness enhancing mechanism is configured such that the stator permanent magnet generates a radial attractive force to the rotor permanent magnet and the axial driving body generates an axial repulsive force to the rotor permanent magnet, wherein a torsional stiffness of the rotor is enhanced through a combined action of the radial attractive force and the axial repulsive force, and wherein a magnitude of the axial repulsive force is capable of decreasing when an axial distance between the axial driving body and the rotor permanent magnet increases, and the magnitude of the axial repulsive force is capable of increasing when the axial distance between the axial driving body and the rotor permanent magnet decreases.