Rotary Encoder Registration Features for Alignment Accuracy

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Solution Overview

Problem

Existing rotary encoders face challenges in maintaining accurate rotational characteristic measurement due to misalignment between active and passive parts and the rotating part, leading to inaccuracies in determining rotational characteristics.

Innovation Solution

The apparatus comprises a rotary member supported by a bearing, with a rotary encoder and sensing arrangement registered to maintain alignment, using registration features and a sensing arrangement to generate signals indicative of rotational characteristics, and an encoder support body with registration features and an angular locator mechanism to ensure precise alignment and stability.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If traditional rotary encoder assembly is used, then the encoder can measure rotational characteristics, but misalignment between active and passive parts occurs leading to measurement inaccuracies

Engineering Contradiction:

Improverotational characteristic measurement accuracyVSAvoidalignment between encoder parts

Core Design Contradiction:

Measurement precisionVSManufacturing precision

Solution Approach 1:

The encoder assembly is divided into distinct modular components: a first component (encoder hub) that attaches to the rotary member, a second component (encoder body) containing the sensing arrangement, and a bearing. Each component has specific registration features that guide precise alignment when assembled, eliminating the need for complex pre-alignment procedures while maintaining measurement accuracy.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Registration features act as intermediary elements between the encoder components and the rotary member. These features include registration protrusions and recesses, as well as bearing registration features, that mediate the alignment process by providing mechanical guidance and constraint during assembly, ensuring accurate positioning without requiring high-precision manufacturing tolerances on all surfaces.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Ease of manufacture

If multiple separate components are used in encoder assembly, then flexibility in installation is improved, but alignment accuracy deteriorates due to cumulative tolerances

Engineering Contradiction:

Improveinstallation flexibilityVSAvoidalignment accuracy

Core Design Contradiction:

Ease of manufactureVSMeasurement precision

Solution Approach 1:

The encoder is designed as an assembly of separate components (encoder hub, encoder body, bearing) that can be manufactured and assembled independently. This segmentation provides installation flexibility while maintaining alignment accuracy through the use of registration features that guide each component into its correct position relative to the others and the rotary member.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent replaces complex mechanical alignment systems (such as precision machined surfaces and adjustment mechanisms) with a simplified registration feature system. The registration protrusions and recesses provide mechanical guidance that automatically ensures proper alignment during assembly, eliminating the need for precision adjustment procedures while maintaining manufacturing flexibility.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

3Measurement precision

If registration features are added to ensure alignment, then measurement precision is improved, but device complexity increases

Engineering Contradiction:

Improvealignment accuracyVSAvoidencoder structure complexity

Core Design Contradiction:

Measurement precisionVSDevice complexity

Solution Approach 1:

Registration features serve as simple intermediary elements that facilitate alignment without adding significant complexity. The registration protrusions and recesses are basic geometric features that can be incorporated into existing component designs with minimal additional manufacturing steps, yet they provide effective alignment guidance.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The registration features enable self-alignment during assembly, where the components automatically position themselves correctly through the mechanical guidance of the registration protrusions and recesses. This self-service alignment mechanism eliminates the need for complex external alignment tools or procedures, maintaining simplicity while ensuring precision.

Inventive Principle:

Principle #25Self-service

Data Source

PatentUS10060767B2Rotary apparatus

Publication Date: 2018.08.28 HEWLETT PACKARD DEVELOPMENT COMPANY LP

AI summary

An example apparatus is described which comprises a rotary member supported by a bearing. A rotary encoder is registered with respect to the rotary member to rotate therewith and a sensing arrangement is registered with respect to a surface of the bearing. The sensing arrangement is responsive to rotation of the encoder to generate a signal indicative of a rotational characteristic of the rotary member.