Adjustable Motor Encoder Assembly for Precise Stator Alignment

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Solution Overview

Problem

Prior art electric motors with encoders rigidly mounted to an endshield suffer from excessive tolerance stack-up, leading to imprecise encoder location relative to the stator, and require labor-intensive manual alignment prone to errors.

Innovation Solution

An electric motor assembly with an adjustable encoder positioned within a recessed encoder channel in the endshield, facilitated by an encoder assembly kit that includes an adjustably positionable encoder, an encoder cover, and an alignment tool with a complemental pin and hole arrangement, allowing for precise alignment and installation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If the encoder is rigidly mounted to the endshield, then the encoder position is fixed and easy to manufacture, but the encoder location relative to the stator becomes imprecise due to tolerance stack-up

Engineering Contradiction:

Improveencoder location precisionVSAvoidencoder mounting structure

Core Design Contradiction:

Manufacturing precisionVSDevice complexity

Solution Approach 1:

The encoder mounting structure transitions from a rigid fixed position to an adjustable position. The encoder can be positioned at different locations along the endshield and secured at the desired position, allowing optimization of encoder-stator alignment while maintaining ease of manufacture through modular design.

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The encoder mounting system is divided into separate components: the endshield with mounting features, the encoder assembly, and the alignment mechanism. This segmentation allows independent optimization of each component and simplifies manufacturing while improving overall positioning precision.

Inventive Principle:

Principle #1Segmentation

2Manufacturing precision

If the encoder is manually adjusted to align the encoder relative to the stator, then the encoder alignment precision can be improved, but the alignment process becomes labor intensive and prone to errors

Engineering Contradiction:

Improveencoder alignment precisionVSAvoidalignment process time

Core Design Contradiction:

Manufacturing precisionVSLoss of time

Solution Approach 1:

Alignment features such as pins, slots, or keyed mechanisms are pre-installed on the endshield and encoder assembly before final assembly. These preliminary alignment features guide the encoder into the correct position relative to the stator, eliminating the need for time-consuming manual adjustment and reducing alignment errors.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

An intermediary alignment mechanism (such as alignment pins, dowels, or precision-machined surfaces) is introduced between the encoder and endshield to transfer and maintain the correct alignment relationship. This intermediary component ensures precise alignment while simplifying the assembly process.

Inventive Principle:

Principle #24Intermediary (Mediator)

Data Source

PatentUS12301066B2Motor encoder assembly providing optimized sensor alignment

Publication Date: 2025.05.13 NIDEC MOTOR CORP

AI summary

An electric motor includes a stator, a rotor rotatable relative to the stator, a housing, and an encoder assembly. The housing defines a motor chamber in which the stator and rotor are at least partly housed. The housing includes an endshield that defines in part the motor chamber. The encoder assembly is configured to sense an operational parameter of the motor and includes an encoder and an encoder cover. The encoder is adjustably positioned within an axially recessed channel of the endshield. The encoder cover is secured relative to the endshield to at least partially overlie the encoder.