Linear Guide Mechanism With Set-Screw Preload and Straightness Correction
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Solution Overview
Problem
Heat treatment of guide members in linear guide mechanisms often results in distortion and reduced straightness, necessitating additional processing like grinding to improve alignment, while increasing ball preload can lead to higher sliding resistance.
Innovation Solution
A linear guide mechanism with heat-treated steel guide members and a pressing mechanism using set screws to adjust ball preload, eliminating the need for grinding and minimizing increased sliding resistance by arranging balls in two rows between guide members in a circular arc configuration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If heat treatment is performed on guide members to increase hardness, then rolling surface hardness is improved, but straightness deteriorates due to distortion
Solution Approach 1:
The guide member is divided into two distinct parts: a heat-treated guide member providing hardness and a separate pressing mechanism (set screws) providing straightness adjustment. This segmentation allows each component to fulfill its specific function without compromising the other - the heat-treated member provides rolling surface hardness while the pressing mechanism corrects any distortion to maintain straightness.
2Manufacturing precision
If ball preload is increased to eliminate rattling and backlash, then positioning accuracy is improved, but sliding resistance increases
Solution Approach 1:
The guide members are designed with circular arc-shaped rolling surfaces instead of flat surfaces. This curvature allows balls to roll more freely while maintaining contact, enabling sufficient preload to eliminate backlash without excessively increasing sliding resistance. The circular arc geometry optimizes the balance between positioning accuracy and motion smoothness.
3Manufacturing precision
If grinding process is added after heat treatment to improve straightness, then manufacturing precision is improved, but device complexity and manufacturing cost increase
Solution Approach 1:
The pressing mechanism using set screws enables the guide member to self-correct its own straightness after heat treatment. Instead of requiring external grinding processes, the distortion is mechanically adjusted by tightening the set screws against the guide member, allowing the component to achieve the required precision through self-adjustment rather than additional manufacturing steps.
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
Improves straightness of guide members without grinding and maintains low sliding resistance even with increased ball preload, effectively addressing distortion and alignment issues.
Implementation Method 1
a pressing mechanism configured to adjust a pre-loading of the balls and improve straightness of the moving block side guide members, is attached to the moving block. Set screws are used as the pressing mechanism.
Implementation Method 2
a plurality of balls disposed in two rows, respectively, between the actuator side guide member and each of the moving block side guide members
Data Source
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AI summary
A linear guide mechanism includes an actuator side guide member (30), moving block side guide members (24) disposed on both sides of the actuator side guide member, and a plurality of balls (36) disposed in two rows, respectively, between the actuator side guide member and each of the moving block side guide members. Set screws (26) that are capable of adjusting a pre-loading of the balls and are capable of improving the straightness of the moving block side guide members, are attached to a moving block.