Captive Contact Screwing Device for Electric Machine Assembly

Resolve Bottlenecks,
Find Innovative SolutionsGenerate Solutions

Solution Overview

Problem

In electrical machines, particularly in compact electric vehicle drives, the limited installation space and component tolerances make it difficult to achieve precise positioning of stator leads and cable lugs, leading to mechanical stresses and a risk of losing threaded pieces during assembly.

Innovation Solution

A device with a holder and receptacle for a threaded piece that allows axial displacement, featuring a captive lock and a multi-round internal profile, enabling precise positioning and compensation for component tolerances, and a flexible or breakable loss prevention mechanism to prevent thread loss during assembly and operation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Volume of moving object

If the installation space is reduced to make electrical machines compact, then the size of the electrical machine decreases, but the positioning precision of stator leads and cable lugs deteriorates

Engineering Contradiction:

Improvesize of electrical machineVSAvoidpositioning precision of stator leads and cable lugs

Core Design Contradiction:

Volume of moving objectVSManufacturing precision

Solution Approach 1:

The device is divided into separate functional components: a holder for positioning, a threaded piece for connection, and a captive lock mechanism for securing. This segmentation allows each component to perform its specific function optimally within the compact space while maintaining positioning precision through the specialized design of each segment.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The threaded piece is nested within the holder, and the captive lock mechanism is integrated into the holder structure. This nesting arrangement maximizes the use of available space within the compact electrical machine while ensuring that the positioning functions are maintained through the hierarchical arrangement of components.

Inventive Principle:

Principle #7Nested doll (Nesting)

2Manufacturing precision

If fixed positioning of electrical connections is attempted to compensate for tolerances, then positioning precision improves, but mechanical stresses increase

Engineering Contradiction:

Improvepositioning precision of electrical connectionsVSAvoidmechanical stresses at screwing point

Core Design Contradiction:

Manufacturing precisionVSStress or pressure

Solution Approach 1:

The threaded piece is designed to be movable within the holder during the assembly process, allowing it to self-adjust to tolerance variations in the electrical connections. This dynamic positioning capability eliminates the need for forced fixed positioning, thereby preventing mechanical stresses while achieving precise alignment through natural adjustment.

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The device enables self-positioning of the threaded piece through its movable design, where the component automatically finds its correct position based on the actual dimensions and tolerances of the electrical connections. This self-service mechanism eliminates the need for external forcing or adjustment, preventing mechanical stresses while ensuring accurate positioning.

Inventive Principle:

Principle #25Self-service

3Reliability

If threaded pieces are firmly fixed in the holder to prevent loss, then reliability improves, but ease of assembly deteriorates

Engineering Contradiction:

Improveprevention of thread lossVSAvoidease of assembly of threaded piece

Core Design Contradiction:

ReliabilityVSEase of manufacture

Solution Approach 1:

The captive lock mechanism is pre-configured in the holder to automatically engage with the threaded piece during the assembly process. This preliminary preparation of the locking mechanism ensures that the threaded piece is securely held without requiring complex fixation steps, maintaining ease of assembly while preventing loss.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The captive lock mechanism acts as an intermediary between the holder and the threaded piece, providing a simple yet effective connection that prevents loss during assembly. This intermediary element facilitates easy assembly by providing a straightforward engagement mechanism while ensuring the threaded piece remains securely in place throughout the assembly process.

Inventive Principle:

Principle #24Intermediary (Mediator)

Data Source

PatentEP3567678B1Device for contact screwing, electric machine with device for contact screwing and contact screwing

Publication Date: 2022.07.13 VOLKSWAGEN AG

Figure 1
Figure 2~3b
Figure 4

AI summary

To provide a device for contact screwing, in particular a high-voltage contact screwing for an electric machine, in which mechanical stresses are reduced and which is easy to install, a device (100) for manufacturing a contact screwing, in particular a high-voltage contact screwing (10) for an electric machine (11), comprising a holder (12) with a receptacle (13) and a locking device (20), wherein a threaded piece (14) is held displaceably in the receptacle (13) at least in an axial direction (33) of the threaded piece (14), wherein the threaded piece (14) is held securely in the receptacle (13) by means of the locking device (20), wherein the device is designed such that the threaded piece (14) is displaceable relative to the device in the manufactured contact screwing.