Centering Jig for Electric Motor Stator Alignment

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Solution Overview

Problem

The existing methods for assembling electric motors in electric turbochargers face challenges in achieving a highly accurate coaxial alignment between the rotor and stator, leading to unbalanced operation, increased vibration, and noise due to misalignment and deformation during the assembly process.

Innovation Solution

A motor assembling method that utilizes a centering jig to accurately position the stator and rotor within the housing, ensuring concentric arrangement by fitting the stator to the housing using a shaft and flange portion, and then inserting the rotor and bearings, with optional use of thermal conduction members and fastening bolts for secure fixation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If the stator is inserted into the stator housing and centering is performed by fitting the outer peripheral surface of the stator to the inner peripheral surface of the stator housing, then the stator can be positioned, but the outer peripheral surface of the stator deforms and highly accurate centering cannot be performed

Engineering Contradiction:

Improvecentering accuracy of statorVSAvoiddeformation of stator outer peripheral surface

Core Design Contradiction:

Manufacturing precisionVSShape

Solution Approach 1:

The stator is temporarily fixed to the stator housing before insertion to establish a precise reference position. This preliminary positioning action allows the stator to be accurately centered on the housing without deformation during the actual insertion process, as the reference position is already established.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

A positioning pin is introduced as an intermediary element between the stator and stator housing. The positioning pin fits into a positioning hole to provide precise locational reference, enabling accurate centering without direct contact between the stator outer surface and housing inner surface that would cause deformation.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Ease of manufacture

If centering is performed on the stator and rotor at mutually different positions, then the assembly process can be simplified, but it is difficult to set highly accurate coaxial degree between rotor and stator

Engineering Contradiction:

Improveassembly process simplicityVSAvoidcoaxial degree between rotor and stator

Core Design Contradiction:

Ease of manufactureVSManufacturing precision

Solution Approach 1:

The positioning holes in the stator and rotor are designed to align with the same reference position on the stator housing. This merging of reference positions ensures that both components are centered at the same location, achieving high coaxial degree while maintaining assembly simplicity through the use of standardized positioning features.

Inventive Principle:

Principle #5Merging (Combining)

3Ease of operation

If the rotor is inserted into the center portion of the stator and the bearing housing is fixed to the insertion opening, then the rotor can be supported, but the shaft centers of the rotor and stator become misaligned leading to unbalanced operation and vibration

Engineering Contradiction:

Improverotor support and bearing installationVSAvoidoperational stability and balance

Core Design Contradiction:

Ease of operationVSStability of the object's composition

Solution Approach 1:

The stator is temporarily fixed to the stator housing before rotor insertion to establish a precise reference position. This preliminary action ensures that the rotor will be inserted at the correct location, preventing misalignment between shaft centers and ensuring balanced operation, while still allowing easy rotor installation.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The positioning pin serves as an intermediary that guides the rotor to the correct position during insertion. This ensures accurate alignment between the rotor shaft center and stator shaft center, preventing operational imbalance and vibration while maintaining ease of installation.

Inventive Principle:

Principle #24Intermediary (Mediator)

Data Source

PatentUS11418095B2Motor assembling method, centering jig, and electric motor

Publication Date: 2022.08.16 MITSUBISHI HEAVY IND ENGINE & TURBOCHARGER LTD

AI summary

A motor assembling method for an electric motor includes inserting a stator of the motor into a first housing of the motor through an opening of the first housing; fitting a shaft portion of a centering jig to an inner peripheral surface of the stator and a mounting portion of a first bearing of the motor in the first housing, and fitting a flange portion to the opening; fixing the stator on which centering is performed using the centering jig to the first housing; removing the centering jig from the first housing; and inserting a rotary shaft of the motor, the first bearing, and a second bearing of the motor into the first housing, and fixing a second housing of the motor to the opening.