Linear Motion Guide Tubular Return Passage
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Solution Overview
Problem
Conventional linear motion guide units face challenges in maintaining lubrication for cylindrical rollers, leading to alignment issues and insufficient mechanical stiffness, which affects their service life and maintenance-free operation, especially in advanced machinery requiring reduced lubricant consumption and high reliability.
Innovation Solution
A linear motion guide unit with a tubular composition comprising a tubular skeleton and cellular members, where the cellular members are impregnated with lubricant and fit into windows of the tubular skeleton, providing a return passage with enhanced mechanical stiffness and ensuring steady lubricant application to all rolling surfaces and axially opposite ends of the rollers, allowing for maintenance-free operation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a conventional return passage structure is used, then the device complexity is low, but the mechanical stiffness is insufficient causing alignment issues with cylindrical rollers
Solution Approach 1:
The return passage is constructed using a composite structure combining a tubular skeleton made of synthetic resin with cellular members made of sintered resinous material. This composite design provides enhanced mechanical stiffness and structural support while maintaining the lubrication function, resolving the alignment issues with cylindrical rollers that occurred with conventional single-material structures.
2Reliability
If periodic lubricant replenishment is performed, then the lubricant film between rolling elements and race is maintained, but the maintenance-free operation requirement cannot be met
Solution Approach 1:
The cellular members are made of sintered resinous material with a porous structure that absorbs and stores lubricant. This porous structure allows the return passage to function as a lubricant reservoir, continuously supplying lubrication to the rolling elements without requiring periodic external replenishment, thereby achieving maintenance-free operation.
3Force
If cylindrical rollers are used instead of balls, then the load-carrying capacity is improved, but the alignment problems and lubrication issues increase
Solution Approach 1:
The composite structure of tubular skeleton and cellular members provides the mechanical stiffness needed to maintain proper alignment of cylindrical rollers, while the porous cellular members ensure adequate lubrication. This combination enables cylindrical rollers to function reliably with improved load-carrying capacity without suffering from alignment problems.
4Reliability
If lubricant-containing polymer is used, then the lubrication is improved, but the production complexity and cost increase
Solution Approach 1:
The cellular members made of sintered resinous material provide a porous structure that naturally absorbs and retains lubricant through capillary action. This approach achieves effective lubrication without requiring complex lubricant-containing polymer compositions or specialized molding processes, simplifying production while maintaining reliability.
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 ensures efficient lubrication and reduced maintenance for cylindrical rollers, enabling long-lasting service life and reliable operation in harsh environments without the need for periodic lubricant replenishment, while maintaining mechanical strength and minimizing debris-related issues.
Implementation Method 1
a cellular member made of a sintered resinous material... impregnated in advance with a lubricant to fill cells or pores with the lubricant
Data Source
AI summary
A linear motion guide unit is disclosed in which a tubular composition to provide a return passage is high in mechanical stiffness and also makes certain of steady application of lubricant to rolling elements rolling through the return passage, thereby ensuring proper lubrication under maintenance-free operation. The return passage is defined inside a hole of a tubular composition installed in an axial bore made in the carriage of a slider. The tubular composition is composed of a tubular skeleton made therein with a window, and a cellular molded member that fits into the window. The rolling elements of cylindrical roller, when coming into rolling-contact with the cellular member while rolling through the return passage, are applied with lubricant film.