Motor Lamination Pack Bonding for Sheet Coplanarity
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Solution Overview
Problem
Existing methods for assembling laminations packs in electric machines face issues with sheet coplanarity due to the limitations of weld beads, which can affect magnetic performance and cause deviations in sheet alignment, leading to production quality problems.
Innovation Solution
A method involving the use of adhesion substances applied to subgroups of sheets before or during stacking, ensuring stable connection through chemical-physical action, particularly in regions distant from welding, to maintain coplanarity and correct axial thickness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If weld beads are used to connect sheets in the pack, then the sheets are strongly joined and the connection is long-lasting, but the weld beads affect magnetic performance and cause deviations in sheet coplanarity
Solution Approach 1:
The patent introduces an intermediary substance (adhesive or bonding agent) to join the sheets instead of using weld beads. This mediator allows the sheets to be connected without direct metal-to-metal contact, thereby avoiding the distortion and coplanarity deviations caused by welding while still achieving strong, long-lasting bonds. The adhesive acts as a buffer that prevents the harmful thermal and mechanical effects of welding on sheet alignment.
Solution Approach 2:
The patent replaces the mechanical/thermal welding system with a chemical bonding system. Instead of using heat and pressure to fuse metal sheets together through welding, the invention uses adhesive substances that chemically bond the sheets. This substitution eliminates the harmful effects of welding on magnetic performance and sheet coplanarity while maintaining connection strength.
2Reliability
If weld beads are positioned to avoid polar expansions, then magnetic performance is maintained, but the useful areas for joining are limited to outer mantle surface only
Solution Approach 1:
The adhesive substance serves as an intermediary that enables joining in areas where welding cannot be applied. Since the adhesive can be applied to the inner mantle surface and polar expansions without the restrictions of welding accessibility, it provides joining capability in all useful areas while maintaining magnetic performance by avoiding weld beads near polar expansions.
Solution Approach 2:
The adhesive bonding system provides universal joining capability across all surfaces of the sheet pack, including inner and outer mantle surfaces and polar expansions. Unlike welding, which is limited to outer surfaces, the adhesive can be applied universally to any area requiring joining, thereby expanding the useful areas for joining while maintaining magnetic performance.
3Device complexity
If sheets are stacked without adhesion substances, then the stacking process is simpler, but the sheets deviate from coplanarity especially at ends distant from welding regions
Solution Approach 1:
The adhesive substances are applied to the sheets before stacking, performing the bonding action in advance. This preliminary application ensures that when sheets are stacked, the adhesion force immediately acts to maintain coplanarity, preventing deviations from occurring in the first place, especially at ends distant from welding regions.
Solution Approach 2:
The invention changes the bonding parameter from mechanical/thermal (welding) to chemical (adhesion). This parameter change allows for effective bonding without the need for complex welding equipment and processes, thereby reducing device complexity while simultaneously improving sheet coplanarity through the uniform distribution of adhesive substances across the sheet surfaces.
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 method enhances sheet coplanarity and axial alignment, reducing deformations and ensuring consistent production quality by stabilizing the structure, even in areas where welding is not feasible.
Implementation Method 1
providing for at least a subgroup of said sheets constituting the pack of sheets, at least at one region of the reciprocal contact surfaces of the sheets, substances of mutual adhesion for the solidarization of the sheets of the subgroup, which substances can be activated by chemical-physical action
Data Source
AI summary
A method and a plant for making packs of metal sheets forming rotors or stators of electric machines or the like by stacking a predetermined number of metallic sheets and stably connecting those sheets along at least two weld beads in opposing or different angular positions, include providing at least one subgroup of the metallic sheets defining the pack of sheets, and disposing, at least at one region of reciprocal contact of the surfaces of the sheets, one or more adhesive substances that solidarize the sheets of the subgroup. The one or more adhesive substances can be activated by chemical-physical action, and the solidarization of the subgroups of sheets is carried out before stacking with the remaining sheets of the pack, or in one or more steps subsequent to the stacking, simultaneously or separately to the application of the weld beads.