Coreless Motor Potting Fixture for Coaxial Stator Encapsulation

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Solution Overview

Problem

The coreless motor's manufacturing process faces challenges in ensuring stability and surface flatness of the stator assembly due to non-standard glue coating and difficulty in controlling dimensional accuracy, leading to issues like poor coaxiality, unbalanced magnetic circuit, and friction.

Innovation Solution

A potting method and assembly for coreless motors involving a potting fixture with specific step portions and potting heads that form a controlled potting space, using membranes to ensure uniform encapsulation and symmetry, and grooves to manage glue overflow, preventing contamination and improving surface flatness.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If non-standard glue coating manner is used in the potting process, then the manufacturing process is simpler and easier to operate, but the stability and surface flatness of the stator assembly deteriorate

Engineering Contradiction:
Improveglue coating processVSAvoidsurface flatness
Core Design Contradiction:
Ease of manufactureVSManufacturing precision

Solution Approach 1:

A potting assembly is introduced as an intermediary tool between the glue coating process and the stator assembly. The potting assembly includes a potting shaft with a membrane that uniformly distributes the glue across the stator assembly surface, ensuring both ease of operation and high surface flatness without requiring complex manual coating techniques

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The potting shaft parameters are specifically designed with a membrane having controlled thickness (0.5-2mm) and material properties that enable uniform glue distribution. The potting shaft diameter and length are optimized to match the stator assembly dimensions, ensuring consistent glue coating thickness and surface flatness while maintaining simple operational procedures

Inventive Principle:
Principle #35Parameter changes

2Ease of manufacture

If dimensional accuracy is difficult to control in the potting process, then the manufacturing process is more flexible and easier to implement, but the coaxiality and magnetic circuit balance deteriorate

Engineering Contradiction:
Improvepotting process flexibilityVSAvoidcoaxiality
Core Design Contradiction:
Ease of manufactureVSManufacturing precision

Solution Approach 1:

The potting assembly serves as a precision intermediary tool that maintains coaxiality during the potting process. The potting shaft is designed with specific dimensional parameters (diameter D1, length L1) that ensure proper positioning and alignment with the stator assembly, achieving high coaxiality while keeping the manufacturing process flexible and straightforward

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The potting assembly creates an equipotential positioning system where the potting shaft and membrane establish uniform dimensional relationships with the stator assembly. This ensures consistent coaxiality and magnetic circuit balance without requiring complex dimensional control measures, maintaining both ease of manufacture and high precision

Inventive Principle:
Principle #12Equipotentiality

3Productivity

If the stator assembly is not uniformly encapsulated, then the manufacturing process is simpler and faster, but the production yield and motor performance deteriorate

Engineering Contradiction:
Improvepotting speedVSAvoidproduction yield
Core Design Contradiction:
ProductivityVSReliability

Solution Approach 1:

The potting assembly with its specifically designed membrane acts as an intermediary that ensures uniform glue distribution and complete encapsulation of the stator assembly. This uniform encapsulation prevents defects and ensures consistent motor performance, thereby improving production yield while maintaining efficient potting speeds through the streamlined process

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The membrane parameters (thickness, material, surface properties) are optimized to ensure complete and uniform glue coverage during the potting process. This parameter optimization guarantees reliable encapsulation that prevents defects and ensures consistent motor performance, improving production yield while maintaining high productivity through an efficient single-step process

Inventive Principle:
Principle #35Parameter changes

Data Source

PatentEP4708646A1Potting method for coreless motor, potting tool and coreless motor
Publication Date: 2026.03.11 SUZHOU HEARTHILL MEDICAL CO LTD
  • EP4708646A1 patent drawingFigure 1
  • EP4708646A1 patent drawingFigure 2
  • EP4708646A1 patent drawingFigure 3

AI summary

Provided in the present disclosure are a potting method for a coreless motor, a potting assembly, and a coreless motor. The potting method includes: providing a stator assembly and a housing, and sleeving the housing on an outer wall of the stator assembly; providing a potting assembly, the potting assembly including a first potting fixture and a second potting fixture; inserting the first potting fixture in the axial direction into one end of the housing, and inserting the second potting fixture in the axial direction into the other end of the housing, so as to form a potting space; and injecting glue into the potting space to form an encapsulation layer to encapsulate the stator assembly on an inner wall of the housing. The potting method of the present disclosure uses the potting assembly to fix the stator assembly of the coreless motor in the housing, thus improving the stability of the stator assembly in the potting process. Using the mode of insertion of the potting assembly, a standard potting space is formed, and the glue is injected into the standard potting space to form the encapsulation layer so as to encapsulate the stator assembly.