Contact Hook Groove Closure for Compact Motor Winding Welding

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Solution Overview

Problem

The challenge in producing electric machines, particularly externally excited synchronous machines, is to simplify the production process while maintaining high efficiency, power density, and compact design. The existing methods, such as using fork-shaped contacting elements, face difficulties in automatic wire insertion due to tensile forces and require additional installation space, reducing power density.

Innovation Solution

A contact hook with a fastening portion and a hook portion is designed to form a groove for receiving a wire. The hook portion has a free end that forms a groove opening, allowing easy wire insertion. In the second assembly state, the free end rests against the fastening portion, creating a plane-parallel contact surface for resistance welding, enabling a compact and efficient electrically conductive connection.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If fork-shaped contacting elements are used for wire connection, then the wire can be mechanically supported, but automatic wire insertion becomes difficult due to tensile forces and additional installation space is required

Engineering Contradiction:

Improvemechanical stability of wire connectionVSAvoidcomplexity of wire insertion process

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

Instead of using a fork-shaped contact that requires the wire to be inserted from the outside and clamped between two legs, the invention uses a hook-shaped contact where the wire is inserted into a groove and then the groove is closed by bending the free end onto itself. This inverts the traditional approach: rather than clamping the wire from opposite sides, the wire is enclosed from the inside by forming a loop, which eliminates the tensile force problem and enables automatic insertion.

Inventive Principle:

Principle #13The other way round (Inversion)

2Reliability

If additional installation space is provided for wire connection components, then reliable electric contact can be achieved, but power density of the electric machine decreases

Engineering Contradiction:

Improvequality of electric contactVSAvoidpower density of electric machine

Core Design Contradiction:

ReliabilityVSPower

Solution Approach 1:

The hook portion is designed to be bendable such that the free end can be folded back and attached to the fastening portion, creating a nested structure where the wire connection is formed within the existing component footprint. This nesting eliminates the need for additional axial installation space while maintaining reliable electric contact through the welded hook structure.

Inventive Principle:

Principle #7Nested doll (Nesting)

3Strength

If the hook portion is made rigid to maintain structural strength, then mechanical stability is improved, but wire insertion becomes difficult and welding quality decreases

Engineering Contradiction:

Improvestructural strength of contact hookVSAvoidease of wire insertion and welding

Core Design Contradiction:

StrengthVSEase of manufacture

Solution Approach 1:

The hook portion is designed with specific material properties and geometric characteristics that allow it to be flexible during the wire insertion and welding process, but rigid once the wire is secured. The hook can be bent to close the groove opening for welding, and this dynamic behavior enables both easy manufacture and structural strength in the final assembled state.

Inventive Principle:

Principle #15Dynamics

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 contact hook simplifies the winding process by allowing easy wire placement and reduces mechanical stress on the wire, enhancing the mechanical stability and resistance welding quality. This design also minimizes axial installation space, thereby increasing the power density of the electric machine.

Implementation Method 1

provides a first contact surface for a resistance welding electrode, and a hook portion adjoining the fastening portion, which provides a second contact surface for a resistance welding electrode

Methodology Applied

Scientific EffectResistance welding: Welding

Data Source

PatentUS20250118906A1Contact hook and contact arrangement for providing an electric contact to a winding arrangement of an electric machine and method of producing a contact arrangement

Publication Date: 2025.04.10 AUDI AG

AI summary

A contact hook for providing an electric contact to a winding arrangement of an electric machine, with a fastening portion for fastening to the electric machine, which provides a first contact surface for a resistance welding electrode, and a hook portion adjoining the fastening portion, which provides a second contact surface for a resistance welding electrode. The hook portion is formed and arranged for forming with the fastening portion a groove for receiving a wire connected to the winding arrangement in a first assembly state, in which a free end of the hook portion forms, at a distance from the fastening portion, a groove opening for inserting the wire into the groove. The free end of the hook portion in a second assembly state rests against the fastening portion, closing the groove opening.