Laminated Pole-Piece Motor for Dishwasher Pump Demagnetization Control
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Solution Overview
Problem
Existing two-phase synchronous electric motors for dishwashers suffer from high demagnetization effects and Joule losses due to the physical limitations of SMC materials, leading to increased costs and reduced performance.
Innovation Solution
The motor design features a core lamination-pack stator with pole pieces having a free end portion composed of a single core lamination pack extending in parallel planes to the rotation axis, reducing demagnetization and Joule losses by optimizing flux distribution and using aluminium windings instead of copper.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If SMC material is used for core and pole piece free end, then manufacturing cost is reduced and assembly is simplified, but demagnetization effect increases and flux distribution becomes concentrated in core central area
Solution Approach 1:
The pole piece is divided into two distinct parts: a core made of SMC material for cost-effective manufacturing, and a free end portion made of laminated steel for optimal flux distribution. This segmentation allows each part to contribute its advantageous properties while mitigating the drawbacks of using a single material throughout.
Solution Approach 2:
The invention uses a composite structure combining SMC material and laminated steel in the pole piece assembly. The SMC core provides economical manufacturing and structural support, while the laminated steel free end portion ensures proper magnetic flux distribution and reduces demagnetization effects.
2Shape
If core and free end portion are made enbloc from SMC material, then structural compactness is improved, but flux flow concentration occurs in core central area preventing extension on whole height of pole piece end
Solution Approach 1:
The pole piece is divided into two distinct parts: a core made of SMC material for cost-effective manufacturing, and a free end portion made of laminated steel for optimal flux distribution. This segmentation allows each part to contribute its advantageous properties while mitigating the drawbacks of using a single material throughout.
Solution Approach 2:
Different materials are used in different regions of the pole piece: SMC material in the core region where structural support is needed, and laminated steel in the free end portion where optimal flux distribution is critical. This local differentiation of material properties resolves the contradiction between compactness and flux distribution.
3Quantity of substance
If cylindrical core is used to decrease copper wire quantity, then material cost is reduced, but negative demagnetization effect occurs due to poor electromagnet linkage
Solution Approach 1:
The invention uses a composite structure combining SMC material and laminated steel in the pole piece assembly. The SMC core provides economical manufacturing and structural support, while the laminated steel free end portion ensures proper magnetic flux distribution and reduces demagnetization effects.
4Volume of moving object
If main and auxiliary cores are placed closer to reduce size, then structural compactness is improved, but pump pick-up voltage increases and leakage reactance increases
Solution Approach 1:
The invention optimizes the geometric parameters of the pole pieces, particularly the dimensions and positioning of the free end portion, to achieve a balance between structural compactness and electromagnetic performance. By carefully controlling the air gap and flux path length, the design reduces leakage reactance while maintaining a compact motor size suitable for dishwasher pumps.
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 significantly reduces demagnetization and Joule losses, achieving improved electromagnetic performance and cost-effectiveness while maintaining mechanical priming capabilities.
Implementation Method 1
a core lamination-pack stator (4), wherein a first and second pairs of pole pieces (8, 7) define a housing/rotation seat (5) for said rotor (2), wherein each pole piece (8, 7) comprises a core (9), having an end (14) being associated to said core lamination pack (10) and a free end portion (11), facing, said rotor housing/rotation seat (5), a coil (12) for a stator winding on a corresponding support (13) being wedged on said core (9)
Data Source
AI summary
A two-phase synchronous electric motor, comprising a permanent-magnet rotor rotating around a rotation axis, and a core lamination pack stator. First and second pairs of pole pieces define: a housing/rotation seat for the rotor. Each pole piece comprises a core, having an end associated to the core lamination pack, a free end portion facing the rotor housing/rotation seat, and a coil. The free end portion of the core of each pole piece comprises a core lamination pack extending in parallel planes to the rotation axis of the rotor. The core laminations have a variable length to form a surface of the free end portion of the core of each pole piece that is concave in the axial direction and partially wraps the rotor. A coupling between the rotor and a load is through a motion transmission joint having driving and driven elements associated in a kinematic series.