Rotary Encoder Tolerance Ring Radial Clamping
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Solution Overview
Problem
Rotary encoders, especially bearingless types, face challenges in maintaining measurement accuracy and reliability due to conditions such as temperature fluctuations and vibrations, which can alter the scanning distance and impair signal quality.
Innovation Solution
The assembly comprises a rotary encoder, a tolerance ring, and a body with a specific radial distance configuration that allows the tolerance ring to be radially clamped between sections of the housing and body, providing an axial stop and maintaining a constant scanning distance, thus preventing displacement and ensuring accurate angular position measurement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a tolerance ring is used to mount the rotary encoder to the body, then the encoder can be installed and positioned, but temperature fluctuations and vibrations can alter the scanning distance and impair measurement accuracy
Solution Approach 1:
The housing is divided into multiple radial sections (first section with first distance, second section with second distance) that work in conjunction with corresponding sections in the body (third section with third distance, fourth section with fourth distance). This segmentation allows the tolerance ring to be positioned and clamped at specific locations to maintain precise scanning distance while enabling installation.
Solution Approach 2:
The patent utilizes controlled radial displacement of the tolerance ring by clamping it between sections with different radial distances. The tolerance ring can radially displace between a first position (when radially clamped) and a second position (when radially uncompressed), allowing adjustment and maintenance of optimal scanning distance under varying thermal and vibrational conditions.
2Measurement precision
If the housing is rigidly fixed to maintain scanning distance, then measurement accuracy is maintained, but the structure becomes more complex and difficult to assemble
Solution Approach 1:
The tolerance ring serves multiple functions automatically: it provides radial clamping to maintain scanning distance, acts as a mounting element for installation, and enables axial positioning through interaction with the body opening. The differential radial distances in the housing and body create self-aligning features that guide assembly without additional complex mechanisms.
Solution Approach 2:
The tolerance ring is designed as a multi-functional component that simultaneously provides mechanical mounting, radial positioning, scanning distance maintenance, and thermal compensation. The housing sections with varying radial distances serve multiple purposes: structural support, positioning reference surfaces for the tolerance ring, and compensation for thermal expansion/contraction.
3Measurement precision
If the tolerance ring is radially clamped to maintain position, then scanning distance is maintained, but the tolerance ring cannot accommodate thermal expansion and vibrations
Solution Approach 1:
The tolerance ring is designed with the ability to dynamically adjust its radial position. It can radially displace between a first position (when radially clamped between housing and body sections) and a second position (when radially uncompressed). This dynamic capability allows the system to maintain measurement precision under varying thermal and vibrational conditions while preserving reliability.
Solution Approach 2:
The housing is designed with sections having different radial distances from the axis (first section with first distance, second section with second distance where first > second). Similarly, the body has corresponding sections (third section with third distance, fourth section with fourth distance where fourth > third). This differential geometry creates compensation mechanisms that account for thermal expansion and contraction, allowing the tolerance ring to maintain proper scanning distance despite temperature changes.
Data Source
AI summary
An assembly includes a rotary encoder having a shaft rotatable about an axis relative to a housing, a tolerance ring and a body accommodating the rotary encoder and the tolerance ring. The housing includes an outer wall having first and second distances from the axis in first and second sections, respectively, the first distance being greater than the second distance. The body has an opening that is: bounded radially by a first inner wall having third and fourth distances from the axis in third and fourth sections, the fourth distance being greater than the third distance; and bounded by a second inner wall which forms an axial stop for the housing. The tolerance ring surrounds the housing and is positioned within the opening such that it is disposed radially between the first and fourth sections and between the second and third sections, and is radially clamped.