Electric Machine Coil Twisting and Gravity Closure for Hairpin Baskets

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Solution Overview

Problem

Existing methods for producing hairpin-shaped winding baskets for electrical machines are inefficient and economically unviable for complex geometries, leading to long process times and high tool complexity, especially when dealing with numerous hairpins or complex wiring patterns.

Innovation Solution

A method involving a screw-in tool with concentrically arranged carriers and a lifting device that allows for the rotation and lifting of hairpin-shaped winding parts, enabling the formation of pigtails and their closure through gravity-induced slipping, eliminating the need for separate tools and process steps.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If hairpins are inserted individually from above or continuously screwed in one by one, then simpler hairpin baskets can be produced, but process time increases and tool complexity increases for complicated hairpin baskets

Engineering Contradiction:
Improveease of producing simple hairpin basketsVSAvoidprocess time
Core Design Contradiction:
Ease of manufactureVSProductivity

Solution Approach 1:

The invention divides the hairpin basket production into two distinct phases: first producing incomplete braids with missing closing hairpins, then assembling these pre-produced segments. This segmentation allows parallel production of multiple braid segments simultaneously, dramatically reducing total process time while keeping tool complexity manageable for each individual braid segment.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The method produces incomplete braids in advance before the final assembly step. By preparing braid segments with missing closing hairpins beforehand, the system enables parallel production of multiple segments, improving overall productivity without requiring complex tools for the entire complete braid.

Inventive Principle:
Principle #10Preliminary action

2Quantity of substance

If the number of hairpins or hairpin braids is too large and the head shape of the hairpins is too protruding, then collisions occur during the insertion process

Engineering Contradiction:
Improvenumber of hairpinsVSAvoidinsertion process reliability
Core Design Contradiction:
Quantity of substanceVSReliability

Solution Approach 1:

By dividing the complete braid into incomplete segments that are produced separately and then assembled, the invention reduces the number of hairpins that need to be handled simultaneously in any single tool. This segmentation eliminates collisions during the insertion process while still achieving the desired large number of hairpins in the final product.

Inventive Principle:
Principle #1Segmentation

3Reliability

If the last winding part to close the hairpin braid is inserted, then the braid is completed, but this procedure is comparatively slow and poses process engineering challenges

Engineering Contradiction:
Improvebraid closing completenessVSAvoidbraid closing speed
Core Design Contradiction:
ReliabilityVSProductivity

Solution Approach 1:

The closing hairpin is prepared in advance as part of the incomplete braid segment production, rather than being inserted separately at the end. This preliminary preparation eliminates the slow final insertion step while ensuring the braid is properly closed during the assembly phase.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The invention merges the production of incomplete braids with the preparation of closing hairpins into a single integrated process. By combining these operations, the system eliminates the separate slow closing step and improves overall productivity.

Inventive Principle:
Principle #5Merging (Combining)

4Productivity

If a continuous twisting tool is used to screw in hairpin-shaped winding parts, then process speed increases, but the tool becomes very complex and expensive in its final expansion stage

Engineering Contradiction:
Improveprocess speedVSAvoidtool complexity
Core Design Contradiction:
ProductivityVSDevice complexity

Solution Approach 1:

The invention segments the braid production into incomplete segments that can be produced with simpler tools, avoiding the need for a single complex continuous twisting tool capable of producing complete braids. Each segment is produced independently with less complex equipment.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Instead of using a tool capable of producing complete braids in one continuous operation, the system uses simpler tools to produce incomplete braids with missing closing hairpins. This partial action approach reduces tool complexity while maintaining acceptable process speed through parallel production.

Inventive Principle:
Principle #16Partial or excessive action

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 method enables the production of both simple and complex winding basket geometries with higher process reliability and shorter cycle times, reducing tool complexity and eliminating the need for additional process steps, thus facilitating more efficient and cost-effective large-scale production.

Implementation Method 1

retracting a lifting device into a braid formed according to b) from twisted winding parts, d) positioning lifting elements in free spaces of the twisted winding parts of the braid according to b), e) lifting the braid in the Z direction and f) closing the braid from according to b) turned-in winding parts due to the plait picked up on the lifting device slipping on the lifting device due to gravity

Methodology Applied
Scientific EffectGravity: Gravitation

Data Source

PatentEP4002658B1Method for producing a coil for an electric machine
Publication Date: 2024.07.31 ROBERT BOSCH GMBH
  • EP4002658B1 patent drawingFigure 1~2
  • EP4002658B1 patent drawingFigure 3~4
  • EP4002658B1 patent drawingFigure 5~6

AI summary

The invention relates to a method for manufacturing a winding for an electric machine. First, winding components (10) are inserted with a first part (14) into a first support (52) and with a second part (16) into a second support (54), wherein one of the supports (52, 54) is movable relative to the other. Subsequently, the first support (52) is rotated (82) about its Z-axis (122) relative to the second support (54), or the second support (54) is rotated relative to the first support (52) to create a twist in the winding components (10). Then, a lifting device (102) is inserted (138) into a formed braid (128) of twisted winding components (10). This is followed by positioning lifting elements (104) in spaces (156) of twisted winding components (10) in the braid (128).Subsequently, the braid (128) is lifted in the Z direction (122) and the braid (128) is closed from twisted winding parts (10) by gravity-induced slippage (130) of the braid (128) received at the lifting device (102) on this.