T-Shaped Magnet Holder Reduces Insertion Friction
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Solution Overview
Problem
Existing rotor units for brushless electric motors face challenges in securely positioning permanent magnets with minimal friction to prevent wear and damage during insertion, as high friction can occur with T-shaped magnet holders.
Innovation Solution
The design features a rotor unit with magnet holders having a head portion that contacts the circumferential face, separated from the shank portion by a distance, reducing friction during magnet insertion and using a magnetic field conductor to enhance mounting efficiency, where the magnet holder only lies on the magnetic field conductor.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If T-shaped magnet holders with full surface contact are used to securely fix magnets, then the magnets are firmly positioned, but friction during insertion becomes undesirably high causing wear or damage
Solution Approach 1:
The magnet holder is designed with differentiated contact regions: the head portion provides localized radial contact on the circumferential face for secure positioning, while the shank portion provides axial contact. This local differentiation allows the head to secure the magnet firmly while limiting the contact area that generates friction during insertion, thus resolving the contradiction between secure positioning and low insertion friction.
2Object-affected harmful factors
If magnet holders with linear contact faces are used, then insertion friction is reduced, but the magnets may not be positioned as securely or accurately
Solution Approach 1:
The magnet holder design incorporates a head portion that extends in the radial direction, adding a dimensional element perpendicular to the axial insertion direction. This radial extension creates a contact surface on the circumferential face that provides secure positioning in the radial direction while maintaining low friction during axial insertion, thus achieving both low insertion friction and high positioning accuracy.
3Strength
If the head portion contacts the circumferential face at the transition area, then magnet fixation is strong, but friction during insertion increases
Solution Approach 1:
The magnet holder is segmented into distinct functional portions: the head portion for radial contact and secure fixation on the circumferential face, and the shank portion for axial contact during insertion. This segmentation separates the fixation function from the insertion function, allowing strong magnet fixation while maintaining low friction during the insertion process.
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
This design ensures precise and secure magnet positioning with reduced friction, preventing wear and damage, resulting in a more robust, efficient, and easier-to-manufacture brushless electric motor with lower rotational inertia.
Implementation Method 1
the head portion (23) lies with only a part of its surface, which forms a contact area (a), on the circumferential face (11) of the permanent magnet (9)... the contact region of the shank portion (22) in a radial direction of the side faces (12, 13)
Implementation Method 2
the friction between the magnet holders and the magnet arrangements is reduced when the magnet arrangements are inserted in an axial direction
Data Source
AI summary
The invention relates to a rotor unit for a brushless electric motor withan annular rotor core surrounding a central axis,a plurality of magnet arrangements that are arranged around the rotor core in a circumferential direction of the rotor and that each have a convex outer peripheral face, an inner contact face, two axial end faces and two side faces pointing in the circumferential direction,a magnet holder having a number of holding portions which are each arranged between two adjacent magnet arrangements and are moulded onto a ring portion of the magnet holder, wherein the holding portions are configured T-shaped in a cross section along a plane running transversely to the central axis and each have a shank portion and a head portion, whereinthe shank portion lies on the side faces of the magnet arrangements in a contact region and the head portion lies on the peripheral faces of the magnet arrangements, whereinthe head portion lies on the peripheral faces in a contact area, which contact area is separated by a distance from a transition between the shank portion and the head portion.