Stator Hairpin Varnish Impregnation With Low-Inertia Rotating Support

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Solution Overview

Problem

Conventional varnish impregnation devices for electric motor stators require heavy and expensive drive motors due to the high moment of rotational inertia and stiffness needed for rotating the stator core, leading to increased manufacturing costs and difficulty in controlling rotation angles.

Innovation Solution

An impregnation device with a first support unit, a second support unit, a rotating unit, a heating unit, and a coating unit, allowing for easy fixation and movement of the stator core, reducing manufacturing costs and improving operation control, by rotating and tilting the stator to facilitate varnish application and curing.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the stator core is fixed to a leading end of a bracket driven to be tilted and rotated, then the stator core can be coated with varnish, but the bracket requires significant stiffness and strength making it very heavy, and the drive motor requires high driving force

Engineering Contradiction:
Improvevarnish coating qualityVSAvoidbracket weight
Core Design Contradiction:
ReliabilityVSWeight of moving object

Solution Approach 1:

The device divides the stator support function into multiple support points (first support unit and second support unit) rather than using a single heavy bracket. The stator core is supported at both ends, distributing the load and eliminating the need for a large, heavy rotating bracket while still enabling effective varnish coating.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The invention extracts the support function from the rotating bracket structure and creates dedicated support units. The first support unit supports one end of the stator core while the second support unit supports the other end, separating the support function from the rotation mechanism and reducing overall system weight.

Inventive Principle:
Principle #2Taking out (Extraction)

2Strength

If the bracket is made with significant stiffness and strength to support the heavy stator core, then the stator can be properly positioned, but the drive motor requires high driving force and high specification

Engineering Contradiction:
Improvebracket strengthVSAvoiddrive motor power
Core Design Contradiction:
StrengthVSPower

Solution Approach 1:

The support function is segmented into two separate support units positioned at opposite ends of the stator core. This distribution of support points reduces the moment arm and rotational inertia compared to a single-bracket system, allowing a smaller, less powerful motor to achieve the same coating quality.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The first support unit and second support unit work together in combination to support the stator core. This distributed support system combines the functions of positioning and support without requiring any single component to be overly strong or heavy, reducing the power requirements of the drive motor.

Inventive Principle:
Principle #5Merging (Combining)

3Ease of operation

If the bracket and stator core have large moment of rotational inertia, then the stator can be rotated for coating, but the drive motor requires high driving force and manufacturing costs increase

Engineering Contradiction:
Improvestator rotation capabilityVSAvoidmanufacturing cost
Core Design Contradiction:
Ease of operationVSEase of manufacture

Solution Approach 1:

By segmenting the support into two separate units at the ends of the stator core, the system reduces the rotational inertia compared to a single large bracket. This allows the stator to be rotated more easily with a less powerful, more cost-effective motor while maintaining the ability to perform comprehensive varnish coating.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The invention uses simpler, less expensive support units instead of a heavy-duty bracket system. These support units provide sufficient functionality for the coating process without the high manufacturing costs associated with building a robust, high-inertia bracket structure.

Inventive Principle:
Principle #27Cheap short-living objects (Disposable)

4Reliability

If a heavy bracket system is used to support and rotate the stator core, then the stator can be coated, but the drive motor is difficult to control for precise rotation angle

Engineering Contradiction:
Improvecoating coverageVSAvoidrotation angle control
Core Design Contradiction:
ReliabilityVSEase of operation

Solution Approach 1:

The segmented support system with two support units creates a more balanced and controllable rotation mechanism. The distributed support points reduce the moment of inertia, making the stator easier to rotate and control at precise angles compared to a heavy single-bracket system, while still ensuring complete coating coverage.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The support units are designed to work dynamically with the rotation mechanism, providing stable support during rotation. This dynamic support system allows for smoother, more controlled rotation with better angle precision compared to a rigid, heavy bracket system.

Inventive Principle:
Principle #15Dynamics

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

The device efficiently impregnates and cures varnish on exposed hairpin ends of the stator core, enhancing insulation and reducing mechanical delamination, while using less expensive components and simplifying operational control.

Implementation Method 1

a heating unit which passes through the stator core, moves in an axial direction of the stator core, is disposed around portions of hairpins exposed from both end portions of the stator core in a longitudinal direction, and heats the portions of the hairpins

Methodology Applied
Scientific EffectHeating: Heating

Data Source

PatentEP4597808A1Device for impregnating varnish into hairpin in stator of electric motor
Publication Date: 2025.08.06 HYUNDAI MOBIS CO LTD
  • EP4597808A1 patent drawingFigure 1
  • EP4597808A1 patent drawingFigure 2
  • EP4597808A1 patent drawingFigure 3

AI summary

This invention relates to an impregnation device for impregnating varnish into portions of a hairpin which is mounted on a stator of an electric motor and exposed from both lengthwise end portions of the stator. The impregnation device of the invention comprises: a first support mechanism abutting around an outer surface of a stator core to support the stator; a second support mechanism on which the first support mechanism is rotatably mounted around the axis of the stator; a first rotation mechanism for rotating the first support mechanism around the axis of the stator core; a heating mechanism which extends through the stator core, moves in the axial direction of the stator core, and is placed on the portions of the hairpin exposed from both end portion in the longitudinal direction of the stator core to heat the portions of the hairpin; a movable mechanism for moving the heating mechanism in the axial direction of the stator core; and an application tool for applying varnish to the portions of the hairpin exposed from both ends in the longitudinal direction of the stator core.