Magnetic Levitation Ball Screw Alignment With Adaptive Gap Control
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Solution Overview
Problem
Conventional ball screw pairs experience precision loss and positioning errors due to wear and misalignment of components, leading to inadequate load-carrying capacity and pre-tightening force, which are difficult to adjust effectively.
Innovation Solution
A magnetic levitation ball screw pair with sensor groups and adaptive excitation coils to measure and adjust gaps and pre-tightening forces, ensuring axial and radial alignment and reducing wear by generating controlled magnetic levitation forces.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If conventional ball screw pair uses balls for load transmission, then load-carrying capacity is achieved, but contact wear causes precision loss and pre-tightening force deterioration
Solution Approach 1:
The patent replaces the traditional mechanical contact-based load transmission system with a magnetic field-based system. Excitation coils generate magnetic fields that interact with magnetic components in the ball screw and nut, creating magnetic levitation forces to support axial loads and magnetic attraction forces to maintain radial pre-tightening force, thereby eliminating mechanical contact wear while maintaining load-carrying capacity and precision
Solution Approach 2:
The patent changes the fundamental operating parameters from mechanical contact forces to magnetic field parameters. By controlling the current in excitation coils, the system dynamically adjusts magnetic field strength to maintain optimal pre-tightening force and load-carrying capacity without the degradation associated with mechanical wear
2Ease of operation
If manual adjustment of pre-tightening force is used, then adjustment capability is provided, but positioning accuracy is insufficient and adjustment is difficult
Solution Approach 1:
The patent incorporates displacement sensors that continuously monitor the gap between the ball screw and nut in real-time. This feedback information is used by the control system to automatically adjust the excitation coil current, maintaining the optimal pre-tightening force and axial gap without manual intervention, thereby achieving both ease of operation and high positioning accuracy
Solution Approach 2:
The system performs self-adjustment of pre-tightening force through the interaction between displacement sensors, control circuits, and excitation coils. The system automatically compensates for wear and maintains optimal parameters without requiring external manual adjustment, enabling the system to serve itself
3Ease of manufacture
If axes of working nut, pre-tightening nut, and screw do not coincide during mounting, then assembly is simplified, but positioning errors occur
Solution Approach 1:
The magnetic field-based pre-tightening mechanism replaces mechanical alignment requirements. The magnetic attraction forces generated by the excitation coils can compensate for minor axis misalignments, allowing the system to achieve precise positioning without requiring extremely tight mechanical alignment during assembly
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The solution enhances precision and reduces wear by maintaining consistent pre-tightening force and alignment, improving the load-carrying capacity and guiding effect of the ball screw pair while preventing positioning errors.
Implementation Method 1
an adaptive excitation coil is mounted to each displacement sensor, the excitation coil is capable of attracting the screw in a measurement direction of the adaptive displacement sensor, and a magnetic force of the excitation coil attracting the screw is adjustable to change the value of the gap
Implementation Method 2
the displacement sensor is capable of measuring a value of a gap between the inner wall of the screw hole and an outer wall of the screw in a diameter direction of the screw hole
Data Source
AI summary
A screw pair including inner walls of screw holes in a working nut and a pre-tightening nut with sensor groups including a plurality of displacement sensors capable of measuring a value of a gap between an inner and outer wall of a screw in a diameter direction of the screw hole, the group includes four displacement sensors evenly distributed in a circumferential direction of the screw hole, every two displacement sensors are paired and symmetrical about a center axis, and projections of a plurality of sensor groups in an axial direction overlap the screw; and an adaptive excitation coil is mounted to each displacement sensor, which is capable of attracting the screw in a measurement direction of the adaptive displacement sensor, and a magnetic force of the coil attached is adjustable to change the value of the gap, so that axes of the screw, working nut, and pre-tightening nut coincide.