Radial Stator Coil Mounting via Holding Grooves

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Solution Overview

Problem

Conventional stator coil mounting methods cause damage to coils during assembly, lead to increased size and copper loss, and complicate automation due to large conversion angles and repeated operations, resulting in inefficiencies and longer manufacturing times.

Innovation Solution

A stator manufacturing apparatus and method utilizing an insertion tool with holding grooves and a pressing tool to guide and push stator coils into slots, reducing damage and optimizing coil placement, allowing for automated and efficient mounting with reduced coil end projection.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If stator coils are pushed into slots using conventional inserter device with large conversion angle, then mounting is achieved, but wire materials are possibly damaged

Engineering Contradiction:
Improvecoil mounting processVSAvoidcoil integrity
Core Design Contradiction:
Ease of manufactureVSReliability

Solution Approach 1:

Instead of pushing coils from the axial end surface (conventional method), the invention pushes coils from the radial direction through holding grooves formed on the outer peripheral surface of the insertion tool. This inverted approach reduces the conversion angle and prevents wire damage during mounting.

Inventive Principle:
Principle #13The other way round (Inversion)

Solution Approach 2:

The holding grooves formed on the outer peripheral surface of the insertion tool serve as intermediaries to guide and support the side portions of stator coils during insertion. These grooves enable smooth radial movement of coils into slots without direct contact between the push-up shaft and coil wires, preventing damage.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Ease of manufacture

If coil size is increased to accommodate large conversion angle mounting, then mounting is achieved, but copper loss increases and efficiency deteriorates

Engineering Contradiction:
Improvecoil mounting processVSAvoidcopper loss
Core Design Contradiction:
Ease of manufactureVSLoss of energy

Solution Approach 1:

The inverted mounting approach from radial direction enables use of smaller, more efficient coils with reduced copper loss, as coils no longer need to accommodate large conversion angles and extended end portions.

Inventive Principle:
Principle #13The other way round (Inversion)

3Reliability

If repeated molding operations are performed for three-phase coils, then coil end portions are prevented from protruding inwardly, but manufacturing time increases

Engineering Contradiction:
Improvecoil positioning accuracyVSAvoidmounting speed
Core Design Contradiction:
ReliabilityVSProductivity

Solution Approach 1:

The holding grooves are pre-formed on the insertion tool at positions corresponding to each slot, and coils are pre-positioned in these grooves before insertion. This preliminary arrangement eliminates the need for repeated molding operations during mounting, as coils are already correctly positioned and oriented.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The invention combines the positioning, orientation, and insertion functions into a single radial pushing operation through the holding grooves, eliminating the need for separate molding operations that were previously required for three-phase coils.

Inventive Principle:
Principle #5Merging (Combining)

4Productivity

If automated mounting is implemented with conventional method, then productivity increases, but coil damage occurs due to large conversion angle

Engineering Contradiction:
Improvemounting speedVSAvoidcoil integrity
Core Design Contradiction:
ProductivityVSReliability

Solution Approach 1:

The radial insertion approach inverts the conventional axial pushing method, enabling automated mounting without the large conversion angle that causes coil damage. The holding grooves guide coils smoothly into slots during automated radial insertion.

Inventive Principle:
Principle #13The other way round (Inversion)

Solution Approach 2:

The holding grooves act as intermediaries that protect coil wires during automated insertion by providing a guided path from the radial direction, eliminating the need for large-angle conversion that damages coils in conventional automated methods.

Inventive Principle:
Principle #24Intermediary (Mediator)

Data Source

PatentEP3118978B1Stator manufacturing device and manufacturing method
Publication Date: 2020.02.05 NITTOKU CO LTD
  • EP3118978B1 patent drawingFigure 1
  • EP3118978B1 patent drawingFigure 2(a)~2(b)
  • EP3118978B1 patent drawingFigure 3(a)~3(b)

AI summary

A stator manufacturing apparatus (20) includes an insertion tool (21) inserted into a stator core (10), the insertion tool (21) having a plurality of holding grooves (23) formed on an outer periphery, the insertion tool (21) being configured such that a pair of side portions (16a, 16b) of a stator coil (16) are disposed in two of the holding grooves (23) separated by a predetermined width; and a pressing tool (30) having a plurality of plate-like pushers (33) narrowed toward tips arranged on a pressing body (32) in correspondence with the positions of the plurality of holding grooves (23) of the insertion tool (21). The pressing tool (30) is configured to push the pairs of side portions (16a, 16b) of the stator coils (16) inserted in the holding grooves (23) radially outwardly and insert the side portions (16a, 16b) into the corresponding slots (12). A recessed groove (24) enabling grippers (17) to be inserted when the stator coil (16) is disposed using the grippers (17) for gripping the pair of side portions (16a, 16b) is formed on the outer periphery of the insertion tool (21).