Ball Screw Reaction Force Sensing for Parallelism Monitoring
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Solution Overview
Problem
Conventional ball screws with parallelism sensors between coupled ball nuts have reduced rigidity and precision due to the sensors being sandwiched, leading to less accurate monitoring of screw shaft parallelism.
Innovation Solution
A ball screw design featuring a screw shaft with a helical external groove and a ball nut with a carrier seat and reaction force sensing modules attached to measure reaction forces on a movable mounting bed, eliminating the need for two ball nuts and allowing real-time monitoring of screw shaft parallelism with improved rigidity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If two ball nuts are coupled with each other to sandwich parallelism sensors between them, then the parallelism of the screw shaft can be monitored in real time, but the rigidity is reduced and precision is reduced
Solution Approach 1:
The patent extracts the sensing function from the ball nut assembly structure. Instead of sandwiching sensors between two ball nuts, the invention uses a single ball nut with a reaction force sensing module that directly measures the reaction force between the ball nut and mounting bed, eliminating the need for the coupled ball nut structure and restoring structural rigidity while maintaining measurement capability
Solution Approach 2:
The patent replaces the mechanical sandwiching structure (two ball nuts with sensors between them) with a reaction force sensing module that directly measures forces. This substitution transitions from a mechanical arrangement that compromises rigidity to a sensing approach that maintains full structural integrity while achieving the same monitoring objective
2Measurement precision
If two ball nuts are coupled with each other to sandwich parallelism sensors between them, then the parallelism of the screw shaft can be monitored in real time, but the precision is reduced
Solution Approach 1:
The sensing function is extracted from the ball nut coupling mechanism. The reaction force sensing module is integrated into a single ball nut structure, eliminating the need for precise coupling between two ball nuts and the associated alignment tolerances, thereby improving manufacturing precision while maintaining measurement precision
Solution Approach 2:
The reaction force sensing module acts as an intermediary that directly measures the force between the ball nut and mounting bed. This intermediary approach provides more direct and accurate measurement information compared to the indirect method of inferring parallelism from sensor readings between coupled ball nuts, thereby improving overall system precision
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 enables precise real-time monitoring of screw shaft parallelism and deflection with increased structural rigidity, enhancing accuracy and convenience by using reaction force sensing modules instead of parallelism sensors, thus improving the operational precision and flexibility of the ball screw.
Implementation Method 1
The reaction force sensing module is attached to the carrier seat and is configured to abut against the mounting bed for measuring a reaction force exerted on the mounting bed by the ball nut during displacement of the ball nut along the screw shaft
Data Source
AI summary
A ball screw mountable on a mounting bed includes a screw shaft having a cylindrical shaft body which extends along an axis, and a helical external groove which is provided on the shaft body, a ball nut having a carrier seat which is rotatably sleeved around the shaft body and which has a carrier portion for carrying the mounting bed, and at least one reaction force sensing module attached to the carrier seat and configured to abut against the mounting bed for measuring a reaction force exerted on the mounting bed by the ball nut during displacement of the ball nut along the screw shaft.