Linear Motion Guide Bearing Rail Geometry for Smooth Ball Circulation
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Solution Overview
Problem
Existing linear motion guide bearings face challenges in maintaining smooth circulation of rolling elements when downsized, due to decreased dimensional accuracy and increased difficulty in assembly and load rating.
Innovation Solution
The design incorporates a rail with specific corner portions forming the rolling surfaces and circulation passages, allowing for increased rolling element diameters and smooth circulation, while using a steel plate rail and resin components for mass production and reduced noise.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If the linear motion guide bearing is reduced in size, then the device becomes more compact, but the circulation of rolling elements becomes rough and assembly becomes difficult
Solution Approach 1:
The invention applies curvature by forming rounded corner portions at the intersections of the bottom wall and side walls in the rail structure. These curved surfaces replace sharp corners, creating smooth circulation paths for the rolling elements. This allows the rolling elements to transition smoothly between different sections of the bearing even in a compact design, maintaining circulation smoothness while achieving downsizing.
2Volume of moving object
If the linear motion guide bearing is reduced in size, then the device becomes more compact, but the load rating decreases
Solution Approach 1:
The invention changes the geometric parameters of the rail structure by forming integrated corner portions with specific curvature radii. These parameter changes optimize the stress distribution and structural efficiency, allowing the bearing to maintain adequate load rating despite reduced overall size. The curved surfaces improve stress flow and prevent stress concentration that would occur at sharp corners.
3Ease of manufacture
If conventional rail structures are used, then manufacturing is simpler, but dimensional accuracy decreases and assembly becomes difficult
Solution Approach 1:
The invention merges the corner portions into an integrated structure formed from a single steel plate. This combining of features into a unified construction maintains dimensional accuracy across the entire rail structure while preserving the simplicity of steel plate manufacturing processes. The integrated design eliminates multiple assembly steps that would compromise precision.
Data Source
AI summary
A linear motion guide bearing 1 includes a rail 10, a slider 20, and a plurality of rolling elements. The slider 20 has formed therein a pair of circulation passages, which are spaces connecting one end and another end in each of a pair of load-carrying races, which are spaces between a pair of first rolling surfaces 41 and a pair of second rolling surfaces 42. In a cross section perpendicular to the longitudinal direction, the rail 10 includes a bottom wall portion 11, a first side wall portion 12, a second side wall portion 13, and a top wall portion 14. One first rolling surface 41 is made up of a wall surface 15A on an inner side of a first corner portion 15, which is a region where the second side wall portion 13 and the bottom wall portion 11 are connected. The other first rolling surface 41 is made up of a wall surface 16A on an inner side of a second corner portion 16, which is a region where the first side wall portion 12 and the top wall portion 14 are connected.