Coil Form Fixation for Resolver Magnet Cores
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Solution Overview
Problem
Existing coil forms for magnet cores in reluctance resolvers lack reliable mechanical fixation, leading to potential slippage and mechanical stress on terminals due to vibrations and temperature changes, and existing solutions like crimped ribs are prone to damage and contamination.
Innovation Solution
The integration of holding ribs on the coil form for an interference fit with the magnet core, combined with crimped ribs in corner regions for centering and tapered recesses for secure mounting, along with modified magnet core structures for efficient layering and reduced manufacturing costs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If catch hooks are used to fix the coil form to the magnet core, then the coil form can be mounted, but the coil form has excessive play and moves during operation causing terminal loads
Solution Approach 1:
The patent replaces the mechanical catch hook fixation system with a deformation-based fixation system. Crimped ribs are formed on the coil form and pressed into corresponding recesses in the magnet core, creating a deformation lock that eliminates play and prevents movement during operation, thereby solving the reliability issue while maintaining ease of manufacture.
Solution Approach 2:
The patent changes the physical state of the crimped ribs from undeformed to deformed during the mounting process. The ribs are initially formed in an undeformed state, then deformed during pressing into the magnet core recesses, creating an interference fit that provides stable fixation without excessive play.
2Reliability
If crimped ribs are formed to prevent rotation and provide interference fit, then rotational fixation is achieved, but the crimped ribs are guided over sharp edges causing high risk of being shorn off
Solution Approach 1:
The patent applies preliminary protective action by providing rounded edges on the magnet core recesses before the crimped ribs are mounted. This preliminary rounding of edges prevents the sharp edges from acting as stress concentration points that could cause the crimped ribs to be shorn off during the deformation process, thereby reducing damage risk while maintaining rotational fixation.
3Reliability
If crimped ribs are deformed for fixation, then interference fit is achieved, but plastics material chips are produced leading to contamination
Solution Approach 1:
The patent converts the potentially harmful chip-generating deformation process into a beneficial process by carefully controlling the deformation geometry. The crimped ribs are designed to deform in a controlled manner into rounded recesses, which achieves the interference fit and fixation strength needed while minimizing chip generation. Any chips that do form are contained within the recesses rather than being released into the environment.
4Ease of manufacture
If magnet cores have higher dimensional tolerances in the direction of layered metal sheets, then manufacturing is easier, but the holding forces of the coil form on the tooth may be insufficient
Solution Approach 1:
The patent compensates for dimensional tolerances by changing the geometric parameters of the crimped ribs and recesses. The ribs are designed with sufficient initial deformation capacity to accommodate tolerance variations in the layered metal sheets while still achieving adequate holding force. The rounded recesses are dimensioned to ensure proper engagement even when core thickness varies within tolerance ranges.
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 solution provides a secure and stable fixation of coil forms, preventing slippage and mechanical stress, while maintaining reliability over the lifespan and reducing contamination risks, with improved accuracy and efficiency in resolver applications.
Implementation Method 1
The integration of holding ribs on the coil form for an interference fit with the magnet core
Implementation Method 2
crimped ribs in corner regions for centering
Implementation Method 3
A magnetic flux transmitter, which is arranged on the stator and generates a given magnetic flux distribution in the gap by means of at least one pole pair
Implementation Method 4
A magnetic flux receiver is further arranged on the stator, and measures the intensity of the magnetic field by means of at least two mutually angularly offset signal pole pairs
Implementation Method 5
both the primary winding and the secondary winding are accommodated on the stator, whilst the rotor influences the magnetic flux circuit without windings, i.e. passively, merely with soft magnetic parts
Data Source
Figure 1~2
Figure 3~5
Figure 6~8
AI summary
The present invention relates to a coil form (100) for mounting on a magnet core (118) for a rotating electrical machine or a resolver and to a corresponding magnet core. The present invention further relates to a magneto-electric angle sensor, in particular a reluctance resolver, the stator of which is constructed by the principles according to the invention. The coil form has a winding form (102) for applying a winding, the winding form (102) comprising a recess (124) for receiving a tooth (116) of the magnet core (118), at least one holding rib (114) being integrally formed and in cooperation with a holding structure (120) of the magnet core (118) fixing the coil form to the tooth. The magnet core comprises a plurality of lamellae (136) manufactured from sheet metal, which are layered on top of one another in a plane-parallel manner and interconnected, every two lamellae which lie on top of one another being rotated through an offset angle relative to one another to form the holding structure (120).