Absolute Encoder Compact Design via Nested Worm Gears
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Solution Overview
Problem
Conventional absolute encoders face challenges in reducing their axial and perpendicular dimensions while maintaining strength, leading to difficulties in achieving a thinner and more compact design without compromising component durability.
Innovation Solution
The proposed absolute encoder incorporates a configuration with a first drive gear, a first driven gear, a second drive gear, and a second driven gear, along with an angular sensor to detect rotation angles, which allows for a reduced size by optimizing the arrangement of components such as the main spindle gear, intermediate gear, and layshaft gear, and using magnetic sensors to detect magnetic flux changes, thereby minimizing magnetic interference and maintaining accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of moving object
If the axial dimension of the absolute encoder is reduced by making each component thinner, then the axial size is reduced, but the strength of each component is reduced and the component may be damaged by vibrations or impacts
Solution Approach 1:
The patent combines multiple functional components (rotating disk with code patterns, light emitting elements, light receiving elements, and processing circuits) into a single integrated rotating assembly. This merging allows the components to support each other structurally while maintaining their functional integrity, reducing the axial dimension without compromising individual component strength.
Solution Approach 2:
The patent implements a nested configuration where light emitting elements and light receiving elements are arranged in overlapping or interleaved patterns on the rotating disk. This nesting allows multiple functional layers to occupy the same axial space, reducing the overall axial dimension while maintaining component strength through shared structural support.
2Area of stationary object
If the dimensions of the absolute encoder in directions perpendicular to the axial direction are reduced, then the overall size is reduced, but the strength of each component is reduced
Solution Approach 1:
The patent transitions from a conventional linear arrangement of components to a radial/concentric configuration where code patterns, light emitting elements, and light receiving elements are arranged in circular patterns around the rotation axis. This dimensional change allows the encoder to achieve compact footprint area while maintaining component strength through the inherent structural stability of radial arrangements.
Solution Approach 2:
The patent merges the code disk, light emitting elements, and light receiving elements into a tightly integrated assembly where components share common mounting structures and support mechanisms. This merging allows the perpendicular dimensions to be reduced while the combined structure maintains sufficient strength to resist vibrations and impacts.
3Adaptability or versatility
If multiple components are stacked in the axial direction to form the absolute encoder, then the functional requirements are met, but the axial dimension is increased
Solution Approach 1:
The patent implements nested positioning where light receiving elements are placed in recesses or between structural features of the rotating disk, and light emitting elements are positioned to project through the same axial space. This nesting allows multiple functional components to occupy overlapping axial spaces, dramatically reducing the total axial dimension while maintaining all required functions.
Solution Approach 2:
The patent arranges code patterns, light emitting elements, and light receiving elements in radial and tangential directions rather than purely axial stacking. By utilizing the circumferential and radial dimensions of the rotating disk, the patent achieves full functional capability with minimal axial height, effectively redistributing component placement across multiple dimensions.
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
This configuration effectively reduces the size of the absolute encoder while preventing decreases in detection accuracy, allowing for a more compact design without compromising the strength and reliability of the components.
Implementation Method 1
an angular sensor configured to detect a rotation angle of a rotating body that is rotated in accordance with rotation of the second driven gear
Data Source
AI summary
An absolute encoder includes a first drive gear (worm gear 1d) configured to rotate in accordance with rotation of a main spindle, and a first driven gear (worm wheel 2a) that engages with the first drive gear. The absolute encoder includes a second drive gear (worm gear 2b) provided coaxially with the first driven gear and configured to rotate in accordance with rotation of the first driven gear, and a second driven gear provided, in a plan view, on a side opposite the first drive gear with respect to the first driven gear and the second drive gear, the second driven gear engaging with the second drive gear. The absolute encoder includes an angular sensor configured to detect a rotation angle of a rotating body that is rotated in accordance with rotation of the second driven gear.