Linear Motion System with Automatic Preload Adjustment
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Solution Overview
Problem
Current double-nut ball screw devices require disassembly for adjusting offset preload, increasing operation time and cost, and reducing production capacity due to manufacturing tolerances and preload shifts.
Innovation Solution
A linear motion system with a preload sensing member and adjusting assembly, utilizing a pulley and belt or adjusting rod driven by a servo motor, electric cylinder, or pneumatic cylinder, allows for automatic adjustment of preload without disassembly, using a controller to detect and adjust the preload value to a preset level.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a preload spacer is disposed between two nuts to provide offset preload, then the preload between nuts is achieved, but the total number of components increases and positioning accuracy deteriorates due to manufacturing tolerances
Solution Approach 1:
The preload spacer is extracted and replaced by an adjustable member that can be integrated into one of the nuts. This eliminates the separate spacer component and its associated tolerance accumulation, while maintaining the preload function through the adjustable mechanism within the nut structure.
Solution Approach 2:
One nut is designed to incorporate both the preload adjustment function and the positioning function. The adjustable member within the nut allows for preload adjustment while the nut itself maintains precise positioning, combining multiple functions into a single component to reduce the number of parts and tolerance accumulation.
2Reliability
If the ball screw device is disassembled to adjust or replace components for preload correction, then the preload can be corrected, but the operation time and cost increase significantly and production capacity decreases
Solution Approach 1:
The preload adjustment mechanism is designed to be dynamically adjustable during operation. The adjustable member can be rotated or repositioned while the ball screw device is running, allowing for real-time preload correction without stopping production, thus maintaining high productivity while ensuring reliable preload.
Solution Approach 2:
The system includes a sensing member that automatically detects preload conditions and provides feedback to control the adjustment mechanism. This self-monitoring and self-adjusting capability eliminates the need for manual disassembly and inspection, enabling automatic preload correction that maintains production capacity.
3Device complexity
If the conventional double-nut ball screw device is used with fixed components, then the structure is simple, but the preload cannot be adjusted after assembly and reliability deteriorates when preload shifts occur
Solution Approach 1:
The nut structure incorporates an adjustable member that can change its position or configuration after assembly. This dynamic element allows the preload to be adjusted or corrected during operation, maintaining reliability while adding minimal complexity to the overall structure compared to fixed-component designs.
Data Source
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AI summary
A linear motion system includes a guiding member, a moving member, a plurality of rolling members, a controller, a preload sensing member and a preload adjusting module. The moving member is slidably disposed on the guiding member, and the moving member and the guiding member together form a circulation path. The rolling members are accommodated in the circulation path. The preload sensing member is disposed on the moving member. The preload sensing member detects a preload value generated by the rolling members and applied to the moving member, and outputs a detecting signal to the controller. The preload driver and adjusting assembly of the preload adjusting module are disposed on the moving member. The controller controls the preload driver to adjust the adjusting assembly according to the detecting signal to adjust the preload value to a preset value.