Axial Gap Motor Bobbin Notch Design for Resin Molding
Solution Overview
Problem
The existing axial gap-type rotary electrical machines face challenges in resin molding, particularly with thermosetting resins, where high pressure is required to fill the resin corners, leading to potential bobbin breakage and difficulties in easy resin flow during stator manufacturing.
Innovation Solution
The axial gap-type rotary electrical machine incorporates a bobbin with a flange portion and notch sections, featuring acute angles and semicircular or semi-elliptical shapes on its side surfaces, which facilitate resin flow and reduce sealing pressure, thereby preventing bobbin breakage during molding.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If high pressure is applied to fill resin to every corner during curing, then complete resin filling is achieved, but bobbin breakage occurs
Solution Approach 1:
The patent applies curvature by forming a recessed portion with a semicircular or elliptical cross-section in the resin mold. This curved geometry eliminates sharp corners that would concentrate stress during resin injection, allowing the resin to flow smoothly into all corners without requiring excessive pressure that would break the bobbin. The recessed portion's curved shape distributes the resin filling process more evenly throughout the core unit assembly.
Solution Approach 2:
The patent segments the resin filling process by creating a recessed portion that separates the filling path from the main resin body. This segmentation allows resin to enter the previously inaccessible corner areas through the recessed portion without subjecting the entire assembly to high pressure, thereby protecting the bobbin while ensuring complete filling.
2Reliability
If high sealing pressure is used to cure thermosetting resin, then curing is initiated and resin fills corners, but resin flow becomes difficult and bobbin may break
Solution Approach 1:
The recessed portion with semicircular or elliptical cross-section provides a curved flow path that reduces resistance to resin flow. This curved geometry allows resin to move more easily into corner areas without requiring high sealing pressure, thereby maintaining ease of manufacture while still achieving complete filling and initiating proper curing.
3Ease of manufacture
If resin mold flows easily without resistance, then manufacturing is simplified, but resin cannot fill corner areas effectively
Solution Approach 1:
The recessed portion segments the resin filling process by creating a dedicated pathway that guides resin into corner areas. This segmentation allows the main resin body to flow easily while simultaneously directing resin into previously inaccessible regions, achieving both ease of manufacture and complete filling.
Solution Approach 2:
The curved cross-section of the recessed portion facilitates smooth resin flow into corner areas without creating sharp corners that would resist flow. This curvature enables resin to naturally follow the recessed portion's shape and fill all areas effectively without requiring high pressure or complex molding procedures.
Data Source
AI summary
This axial gap-type rotary electrical machine has: a stator in which a plurality of core units each configured from a core, a coil, and a bobbin are disposed, centered around a rotating shaft, in an annular shape along the inner circumferential surface of a housing; and a rotor that is face-to-face with a cross-sectional surface of the core through a predetermined gap in a radial direction of the rotating shaft. The bobbin is formed in a cylindrical shape, has flange parts extending a predetermined amount in the outer circumferential direction at the top and bottom of the cylindrical shape, is provided with notch sections on the tip part in the inner circumferential direction of the flange part of the bobbin, and forms an acute angle. In addition, approximately circular notch sections are formed on adjacent side surface portions of the bobbin in the outer circumferential direction of the bobbin. Accordingly, when forming the stator by means of molding, a resin mold is made to easily flow, and damage to the bobbin of the core unit can be avoided.