Length Measuring Device Thermal Decoupling via Segmented Adhesive Bonding
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Solution Overview
Problem
Existing length measuring devices face challenges in maintaining precise position measurements due to temperature fluctuations, which cause measurement errors from thermal expansion, and they often require complex attachment methods that can introduce constraints and inaccuracies.
Innovation Solution
A compact length measuring device design featuring a scale with a negligibly small thermal expansion coefficient, attached to a metal carrier using a combination of inelastic and elastic adhesives to allow for relative movement during temperature changes, and a dowel pin mounting system for secure attachment to objects, ensuring precise and temperature-independent measurements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If the scale is rigidly fixed to the carrier at all positions, then the attachment is secure and simple, but temperature changes cause measurement errors due to thermal expansion constraints
Solution Approach 1:
The attachment is divided into two distinct zones: a fixed point area where the scale is rigidly attached to the carrier, and a remaining area where the scale is mechanically decoupled. This segmentation allows the scale to be securely fixed at the reference point while permitting thermal expansion movement elsewhere, resolving the contradiction between secure attachment and measurement precision under temperature changes.
Solution Approach 2:
Different attachment characteristics are applied to different regions of the scale-carrier interface. At the fixed point, rigid attachment is used for stability; in the remaining area, mechanical decoupling is implemented to allow thermal movement. This local differentiation enables the system to simultaneously achieve secure fixation and temperature compensation.
2Measurement precision
If the scale is mechanically decoupled from the carrier, then temperature-induced measurement errors are reduced, but the attachment becomes more complex
Solution Approach 1:
The attachment mechanism is segmented into a simple rigid fixation at the fixed point and a mechanical decoupling in the remaining area. This segmentation achieves temperature compensation while keeping the overall structure relatively simple, as only the non-fixed areas require special decoupling arrangements.
Solution Approach 2:
A mechanical decoupling mechanism acts as an intermediary between the scale and carrier in the remaining area, allowing relative movement due to thermal expansion while maintaining the overall attachment structure. This intermediary element enables temperature compensation without requiring complete redesign of the attachment system.
3Ease of manufacture
If a single adhesive type is used for the entire scale-carrier interface, then the manufacturing process is simple, but temperature changes cause constraining forces and measurement errors
Solution Approach 1:
Different adhesive characteristics are applied to different regions: an inelastic adhesive is used at the fixed point area for rigid attachment, while an elastic adhesive is used in the remaining area to allow thermal expansion. This local differentiation of adhesive properties enables temperature compensation while maintaining manufacturing feasibility.
Solution Approach 2:
The adhesive properties (elasticity) are changed across different regions of the interface. By varying the elastic modulus parameter of the adhesive from the fixed point outward, the system achieves rigid fixation at the reference point while allowing flexible movement elsewhere, compensating for thermal effects.
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 enables precise and temperature-independent position measurements by decoupling the scale from the carrier during thermal changes and providing a secure, play-free attachment mechanism, enhancing measurement accuracy and reliability.
Implementation Method 1
The scale (1) is rigidly attached to the carrier (3) at a fixed position F - also called a fixed point - in the measuring direction X
Implementation Method 2
the decoupling of the scale (1) from the carrier (3) is realized by arranging an adhesive (5) of high elasticity between the mounting surface (31) and the scale (1)
Implementation Method 3
the scale (1) and the carrier (3) can shift relative to one another when the temperature changes, without constraining forces being exerted
Data Source
AI summary
The present invention relates to a length measuring device with a scale (1) extending in a longitudinal direction (X) and having a measuring scale (11) for position measurement. The scale (1) is rigidly fixed at a fixed position (F) in the measuring direction (X) by means of an adhesive (4) applied to a mounting surface (31) of a carrier (3) and is decoupled from the carrier (3) in the remaining area, so that the scale (1) and the carrier (3) can move relative to each other in the longitudinal direction (X) when temperatures change. To transfer this fixed position (F) for position measurement to the object to be measured, a mounting element (6) is provided, which is connected to the carrier (3) by means of a dowel pin (7) that is pressed into a dowel bore (62) of the mounting element (6) and into a dowel bore (32) of the carrier (3) and runs perpendicular to the measuring direction (X).