Wave Coil Winding for Open-Slot Electrical Machines

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Solution Overview

Problem

Conventional winding processes for round wire are not suitable for producing coil windings with rectangular cross-sections, leading to complex connections and space requirements for electrical machines, and subsequent connections in stators or rotors result in unreliable and space-consuming configurations.

Innovation Solution

A method involving a flat winding template that rotates about a rotational axis, where wires are fed perpendicular and connected in pairs, forming a wire package with integrated bends to create a distributed wave winding, allowing for pre-assembly of electrical connections and space-saving installation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If conventional winding processes for round wire are used, then the process is simple and familiar, but the wire cannot properly fill stator slots and the cross-section utilization is poor

Engineering Contradiction:
Improveslot filling qualityVSAvoidwinding process complexity
Core Design Contradiction:
Manufacturing precisionVSEase of manufacture

Solution Approach 1:

The patent changes the wire cross-sectional shape parameter from circular to rectangular to achieve optimal slot filling. The rectangular wire cross-section allows complete utilization of the stator slot space, eliminating voids and improving electromagnetic performance while maintaining manufacturing feasibility through adapted winding processes.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent develops a universal winding method that can handle both traditional round wires and rectangular wires, as well as different winding patterns (concentrated and distributed windings). This multi-functional approach simplifies the manufacturing process by providing a unified procedure for various wire types and winding configurations.

Inventive Principle:
Principle #6Universality (Multi-functionality)

2Reliability

If wire ends are connected using connectors or permanent bonding after winding, then the electrical connection is achieved, but additional installation space is required and contact resistance increases

Engineering Contradiction:
Improveelectrical connection reliabilityVSAvoidspace requirement in stator
Core Design Contradiction:
ReliabilityVSArea of stationary object

Solution Approach 1:

The patent merges the wire ends directly with each other through integral bending, eliminating the need for separate connectors or bonding processes. The wire ends are bent and joined to form continuous conductive paths, reducing the number of components and eliminating additional installation space requirements while maintaining reliable electrical connections.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The patent performs the wire end connection during the winding process itself, before the winding is completed and installed. By pre-bending and pre-connecting the wire ends in the correct positions during winding, the patent eliminates the need for subsequent connection steps and additional space for connectors.

Inventive Principle:
Principle #10Preliminary action

3Ease of manufacture

If wire ends are connected after coil winding completion, then the winding structure is formed, but additional assembly steps are required and production time increases

Engineering Contradiction:
Improvewinding structure formationVSAvoidproduction time
Core Design Contradiction:
Ease of manufactureVSLoss of time

Solution Approach 1:

The patent performs wire end bending and connection operations during the winding process itself, before the winding is completed. By pre-positioning and pre-connecting the wire ends in their final locations during winding, the patent eliminates subsequent connection steps and reduces overall production time.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent maintains continuous winding operation without interruption for separate connection steps. The winding process continuously forms the coil structure and connects wire ends in an integrated, uninterrupted sequence, eliminating idle time and additional assembly operations.

Inventive Principle:
Principle #20Continuity of useful action

4Manufacturing precision

If rectangular cross-section wires are used, then optimal slot filling is achieved, but conventional round wire winding processes are not suitable

Engineering Contradiction:
Improveslot filling efficiencyVSAvoidwinding process adaptability
Core Design Contradiction:
Manufacturing precisionVSEase of manufacture

Solution Approach 1:

The patent changes the wire cross-sectional shape parameter from circular to rectangular to achieve optimal slot filling. The rectangular wire cross-section allows complete utilization of the stator slot space, eliminating voids and improving electromagnetic performance while maintaining manufacturing feasibility through adapted winding processes.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent develops a universal winding method that can handle both traditional round wires and rectangular wires, as well as different winding patterns (concentrated and distributed windings). This multi-functional approach simplifies the manufacturing process by providing a unified procedure for various wire types and winding configurations.

Inventive Principle:
Principle #6Universality (Multi-functionality)

Data Source

PatentEP3994790B1Method for producing a coil winding for insertion into radially open slots of stators or rotors of electrical machines
Publication Date: 2025.09.10 SCHAEFFLER ELMOTEC STATOMAT GMBH
  • EP3994790B1 patent drawingFigure 1
  • EP3994790B1 patent drawingFigure 2
  • EP3994790B1 patent drawingFigure 3

AI summary

The invention relates to a method for producing a coil winding (70) for insertion into radially open slots (82) in a rotor or stator (80) of an electrical machine, wherein the coil winding (70) has a wire core (60) which consists of a number of wires (32), wherein the wires (32) of the wire core (60) run parallel to one another and are connected to one another in pairs at one end of the wire core (60), and wherein the coil winding (70) is formed by a flat former (26) which can rotate about a rotation axis. According to the method, the wire core (60) is fixed on a former (26) and end windings (42) are produced by displacing fixing means of the wire core (60). The winding shaft (26) is rotatable, so that after the method is carried out there is a coil winding (70) in the form of a shaft winding, which has wires (32) of the wire core (60) that are pre-connected in pairs at one end. A particularly space-saving coil winding (70) which has a particularly high degree of mechanical stability and requires an extremely small amount of installation space in a rotor or stator (80) can be produced using a method of this kind.