Segmented Pusher Arms for Coil Wedge Insertion in Dynamo Electric Machine Cores

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Solution Overview

Problem

The insertion of pre-wound coils and cover wedges into machine core slots often results in insufficient displacement and damage to cover wedges due to high mechanical resistance, leading to unreliable insulation and potential machine core rejection, especially in high wire fill scenarios.

Innovation Solution

A pusher assembly with radially movable arms and a wedge pusher assembly that allows simultaneous or sequential motion of multiple coil branches and cover wedges into the slots, using forms to guide coil branches and reduce resistance, ensuring correct positioning and minimizing damage.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If multiple coil branches are inserted simultaneously into the same slot to achieve high wire fill, then the manufacturing precision and productivity are improved, but the mechanical resistance increases causing cover wedges to be displaced insufficiently or damaged

Engineering Contradiction:

Improvecoil insertion efficiencyVSAvoidcover wedge positioning accuracy

Core Design Contradiction:

ProductivityVSReliability

Solution Approach 1:

The pusher member is divided into multiple independent pushing members, each responsible for pushing a specific coil branch. This segmentation allows each pushing member to independently apply force to its assigned coil branch, distributing the mechanical resistance across multiple components rather than overwhelming a single pusher, thereby enabling successful insertion of multiple coil branches simultaneously while maintaining cover wedge positioning accuracy

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Forms are introduced as intermediary elements that guide the coil branches during insertion. These forms are positioned in specific portions of the slots to provide a controlled path for the coil branches, reducing mechanical resistance and preventing direct contact between the coil branches and slot walls that would increase friction and cause cover wedge displacement issues

Inventive Principle:

Principle #24Intermediary (Mediator)

2Device complexity

If a single pushing device is used to insert multiple coil branches into the same slot, then the device complexity is reduced, but the manufacturing precision deteriorates due to inability to apply sufficient pressing force to each coil branch

Engineering Contradiction:

Improveinsertion device structureVSAvoidcoil branch positioning accuracy

Core Design Contradiction:

Device complexityVSManufacturing precision

Solution Approach 1:

The single pushing device is segmented into multiple independent pushing members, where each pushing member is responsible for a specific coil branch. This allows each pushing member to apply adequate pressing force to its assigned coil branch against the bottom of the slot, ensuring proper positioning and compactness without requiring an overly complex monolithic device structure

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Each pushing member is designed with multi-functionality, serving both to push the coil branch into the slot and to press it against the bottom for proper positioning. The pushing members work in unison as part of a coordinated system, achieving the function of a complex single device while maintaining structural simplicity through modular design

Inventive Principle:

Principle #6Universality (Multi-functionality)

3Ease of operation

If the pushing member moves backwards through the core after insertion stroke, then the ease of operation is improved, but the reliability deteriorates due to potential misalignment and damage during retraction

Engineering Contradiction:

Improvepusher assembly retractionVSAvoidinsertion process stability

Core Design Contradiction:

Ease of operationVSReliability

Solution Approach 1:

Instead of moving the pushing member backwards through the core for retraction, the invention inverts the approach by keeping the pushing member stationary and moving the core forward. This eliminates the risks associated with backward movement through the core, such as misalignment and damage to inserted components, while still achieving the necessary retraction function for subsequent operations

Inventive Principle:

Principle #13The other way round (Inversion)

Data Source

PatentEP2144352B1Apparatus and methods for inserting coils and cover wedges in the slots of dynamoelectric machine cores

Publication Date: 2015.02.11 ATOP SPA

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AI summary

An apparatus for inserting coil branches (13a, 13b) of pre-wound wire coils and cover wedges (14) into slots (11) of a dynamoelectric machine core (10), comprises a first pusher assembly (50) having an insertion stroke for advancing through the bore (10') to insert the coil branches into the slots (11) and a second pusher assembly (96, 97) configured to push the cover wedges (14) into the slots (11) along the coil branches. The second pusher assembly comprises first and second movable supports (96, 97) for pushing first and second groups of wedges (30, 32, 33, 35, 36, 38) into respective slots (11) during a same insertion stroke. The apparatus is provided with radial arms (56', 57', 58') moveable in the radial direction (R) of the core (10) for entering the slots (11) to push coil branches (26") towards the bottom of the slots (11). At least one form member (131-136, 141-143) may be provided for impeding the insertion of a branch of a coil in the respective portion of the slot during at least one insertion stroke of the first pusher assembly (50).