Motor Connection Eyelet Structure for Low-Heat Coil Welding

Resolve Bottlenecks,
Find Innovative Solutions
Generate Solutions

Solution Overview

Problem

The existing connection devices for drive motors in suction devices and machine tools experience high heat concentration during welding, leading to deformation and breakage of coil conductors.

Innovation Solution

A ring-shaped receiving eyelet is used to distribute the welding current through two electrical connection sections, reducing heat concentration and minimizing conductor deformation by ensuring even heat distribution.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If welding current flows through a single connection section, then electrical connection is established, but heat concentration causes conductor deformation and breakage

Engineering Contradiction:
Improveelectrical connection stabilityVSAvoidheat concentration at connection point
Core Design Contradiction:
ReliabilityVSTemperature

Solution Approach 1:

The receiving eyelet is divided into two separate electrical connection sections instead of one, so that the welding current is distributed through multiple paths. This segmentation reduces heat concentration at any single point while maintaining reliable electrical connection.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent transitions from a single-point connection to a distributed multi-point connection structure. By arranging connection sections at different spatial locations around the conductor receptacle, the heat generation is distributed across multiple dimensions rather than concentrated at one location.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

2Reliability

If receiving arm is moved towards base body to close conductor receptacle, then electrical connection is established, but high heat alters coil conductor causing breakage

Engineering Contradiction:
Improveconnection reliabilityVSAvoidconductor strength
Core Design Contradiction:
ReliabilityVSStrength

Solution Approach 1:

The connection structure is segmented into multiple electrical connection sections distributed around the conductor receptacle. This allows the welding current to flow through multiple paths simultaneously, reducing the thermal load on any single section and protecting the coil conductor from excessive heat that would cause breakage.

Inventive Principle:
Principle #1Segmentation

3Ease of manufacture

If welding current flows through base section, then electrical connection is made, but significant heating melts protective coating and damages conductor

Engineering Contradiction:
Improvewelding connection capabilityVSAvoidthermal damage to conductor
Core Design Contradiction:
Ease of manufactureVSObject-affected harmful factors

Solution Approach 1:

The single base section connection is segmented into multiple electrical connection sections. This distributes the welding current across multiple paths, reducing the current density and heat generation at each individual section, thereby preventing thermal damage to the conductor while maintaining welding connection capability.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Different sections of the receiving eyelet are designed with specific local characteristics to optimize current distribution. Each electrical connection section is positioned and dimensioned to handle a portion of the total current, creating localized quality variations that prevent overheating while ensuring reliable connection.

Inventive Principle:
Principle #3Local quality

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 solution effectively reduces conductor heating and minimizes the risk of conductor breakage during welding, ensuring a stable electrical connection.

Implementation Method 1

a welding current is introduced into the connection device via welding electrodes. This current flows primarily through the base section, causing significant heating

Methodology Applied
Scientific EffectJoule heating: Joule Heating

Implementation Method 2

the two electrical connection sections ensure that the welding current does not heat the connection device to a high degree in one area. By utilizing two connection sections, the heat distribution is more even.

Methodology Applied
Scientific EffectHeat distribution: Conduction (thermal)

Data Source

PatentEP3963695B1Drive motor with a connection device
Publication Date: 2026.01.14 FESTOOL GMBH
  • EP3963695B1 patent drawingFigure 1
  • EP3963695B1 patent drawingFigure 2~4
  • EP3963695B1 patent drawingFigure 5~9

AI summary

The invention relates to a drive motor for a suction tool (400) or a machine tool in the form of a hand-held power tool (200, 300) or a semi-stationary machine tool. The drive motor (20, 120) has a stator (80) with an excitation coil assembly (86) and a rotor (40, 140) with a motor shaft (30, 130) which is rotatably mounted on the stator or relative to the stator (80) about a rotational axis (D) by means of a bearing assembly (24A), and the drive motor (20, 120) has a connection device (100) for electrically connecting the drive motor to an energizing device (206, 306) for energizing the excitation coil assembly (86). The connection device (100) has a main part (103) for securing to the stator (80) and a receiving arm (108) which protrudes from the main part (103), a conductor receiving area (107) being formed between the main part and the receiving arm for at least one electric coil conductor (88) of an excitation coil (87) of the excitation coil assembly (86). The connection device (100) has a connection contact region (101) for electrically connecting a connection line (15) for connecting to the energizing device (206, 306). The receiving arm (108) and the main part (103) are connected together by means of two electrically conductive connection regions (118, 119) and form a receiving eyelet (119A) which encircles the conductor receiving area (107) such that the conductor receiving area (107) has a closed state, and a welding current can flow past the conductor receiving area (107) between the main part (103) and the receiving area (108) via the electric connection regions (118, 119).