Linear Guide Thermal Bending Neutral Axis
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Solution Overview
Problem
Existing linear guides for coordinate measuring machines face challenges in achieving high stiffness and low thermal expansion while being insensitive to contaminants and dynamic forces, with solutions like air bearings being costly and prone to wear, and recirculating ball guides experiencing thermal mismatch issues.
Innovation Solution
A linear guide comprising a plate-shaped main body with a first coefficient of thermal expansion and a guide rail with a second coefficient of thermal expansion, connected in a neutral axis to minimize thermal-induced bending, using materials like granite for the main body and steel for the guide rail, and employing recirculating ball or roller guides to maintain stiffness and accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If air bearings are used for guidance, then measurement precision is improved, but device complexity and cost increase, and reliability decreases due to wear and sensitivity to contaminants
Solution Approach 1:
The patent changes the fundamental parameter of the bearing mechanism from fluid-based (air) to solid-based (recirculating ball or roller). This parameter change maintains the low-friction, high-precision guidance function while eliminating the sensitivity to contaminants and wear issues that plague air bearings, thereby improving reliability without sacrificing measurement precision
Solution Approach 2:
The patent substitutes the air bearing mechanical system with a recirculating ball or roller guide mechanical system. This replacement eliminates the need for clean air environments and continuous air supply, making the system more reliable in workshop conditions while maintaining guidance precision through the rolling contact mechanism
2Strength
If recirculating ball guides made from steel are used, then stiffness and reliability are improved, but thermal expansion mismatch with granite main body causes measurement inaccuracies
Solution Approach 1:
The patent explicitly addresses thermal expansion by selecting materials for the guide rail whose coefficient of thermal expansion is compatible with the granite main body. This prevents differential thermal expansion between components during temperature changes, eliminating bending and measurement inaccuracies while maintaining the stiffness benefits of metal guide rails
Solution Approach 2:
The patent employs composite material selection, combining granite for the main body (providing thermal stability and mass) with specifically selected metal materials for the guide rails (providing stiffness and strength). The key is that the metal materials are chosen to have thermal expansion characteristics that match granite, creating a thermally compatible composite structure
3Reliability
If multiple air bearings are used to accommodate dynamic forces, then reliability is improved, but device complexity and cost increase significantly
Solution Approach 1:
The recirculating ball or roller guide system is inherently capable of accommodating dynamic forces and directional loads through its rolling contact geometry and circulation mechanism. This self-service capability eliminates the need for multiple specialized air bearings to handle different force directions, reducing device complexity while maintaining reliability under dynamic conditions
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 provides a linear guide that maintains high stiffness and low thermal expansion, reducing the risk of bending and measurement inaccuracies, while being less sensitive to contaminants and dynamic forces, thus enhancing the performance and reliability of coordinate measuring machines.
Implementation Method 1
the guide rail is arranged in a neutral axis of the plate-shaped main body
Data Source
AI summary
A linear guide for a coordinate measuring machine. The linear guide comprises at least one plate-shaped main body and at least one guide rail. The plate-shaped main body has a material with a first coefficient of thermal expansion. The at least one guide rail has a material with a second coefficient of thermal expansion, which differs from the first coefficient of thermal expansion. The guide rail is connected to the plate-shaped main body, and arranged in a neutral axis of the plate-shaped main body.