Linear Encoder Scale Support Decoupling Thermal Stress
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Solution Overview
Problem
Existing X-Y motion-positioning systems face challenges in accurately mounting encoder scales due to inappropriate mounting, mechanical solicitations, and thermally induced stresses, which can lead to deformation and measurement artifacts, impacting system performance and repeatability.
Innovation Solution
A scale support for an encoder scale of a linear electric motor, featuring a scale receiving part with an encoder scale receiving side and at least two stands connected to the receiving part. Each stand includes a fixation pad fixed to a stationary part of the motor and a decoupling member, such as flexible blades, to mechanically decouple the fixation pad from the encoder scale receiving side, preventing deformation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If the encoder scale is mounted directly on the stationary part of the linear motor, then the mounting structure is simple, but the scale is subjected to mechanical solicitations and thermally induced stresses that cause deformation and measurement artifacts
Solution Approach 1:
The mounting structure is divided into separate functional elements: fixation pads for mounting, stands for structural support, and a scale receiving part for holding the encoder scale. This segmentation allows each element to be optimized independently - the fixation pads can absorb mechanical stresses while the scale receiving part maintains dimensional stability for accurate measurements
Solution Approach 2:
The scale support acts as an intermediary component between the stationary part of the linear motor and the encoder scale. It mechanically decouples the scale from the motor's fixation region, preventing transmission of mechanical solicitations and thermally induced stresses that would otherwise cause scale deformation and measurement artifacts
2Strength
If rigid mounting is used to secure the encoder scale, then the scale is firmly fixed, but thermal expansion and mechanical stresses cause deformation of the scale
Solution Approach 1:
The decoupling members are designed with specific geometric parameters (blade thickness, length, and cross-section) that allow them to flex under thermal expansion and mechanical stresses. This controlled flexibility enables the mounting structure to accommodate parameter changes in the stationary part without transmitting them to the encoder scale, maintaining both firm fixation and dimensional stability
3Reliability
If multiple encoders and mechanical elements are used to shield the scale, then the scale is protected from deformations, but the eigenfrequencies and overall cost of the positioning system are negatively impacted
Solution Approach 1:
The invention extracts and isolates the scale protection function into a dedicated scale support structure with decoupling members. Instead of using multiple encoders and complex mechanical shielding elements, the scale support independently handles the protection task by mechanically decoupling the scale from stress sources, thereby protecting the scale while maintaining system simplicity and eigenfrequencies
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 scale support effectively decouples mechanical displacements from the encoder scale, ensuring that the scale remains undisturbed by external stresses, thereby maintaining high accuracy and precision in positioning systems, even under operating conditions that would typically cause deformation in conventional scale supports.
Implementation Method 1
a decoupling member configured for at least a partial mechanical decoupling between the fixation pad and the encoder scale receiving side such that the displacement of the fixation pad of each stand does not cause a deformation of the encoder scale receiving side
Implementation Method 2
Each stand further comprises a decoupling member configured for at least a partial mechanical decoupling between the fixation pad and the encoder scale receiving side
Data Source
AI summary
A scale support for an encoder scale of a linear electric motor includes a scale receiving part having an encoder scale receiving side, and two stands connected to the scale receiving part. Each stand comprises a fixation pad arranged to be fixed to a fixation region of a stationary part of the electric motor, the fixation pad being subjected to a displacement induced by a displacement of the fixation region when the scale support is mounted on the stationary part and the electric motor is operating. Each stand further comprises a decoupling member configured for a partial mechanical decoupling between the fixation pad and the encoder scale receiving side such that the displacement of the fixation pad of each stand does not cause a deformation of the encoder scale receiving side or a deformation occurring exclusively along a longitudinal direction of the encoder scale receiving side.