Stator Winding Rigid Bar Insertion and Bridge Connection

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Solution Overview

Problem

The complexity and instability of connecting bridges in stator windings with rigid bars make the construction process difficult, leading to challenges in maintaining the desired position and ensuring proper electrical connections.

Innovation Solution

The configuration of 'U'-shaped rigid bars with 'S'- and 'U'-folded cusps allows for easy insertion and bending, reducing mechanical interference and enabling a single bending step, while connection bridges with plastically deformable seats simplify the coupling process by ensuring firm mechanical and electrical contact.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If connection bridges are used to connect the ends of legs, then electrical connections are established, but the construction process becomes complex and the position of connection bridges becomes unstable

Engineering Contradiction:
Improveelectrical connection stabilityVSAvoidconstruction complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent combines the connection bridge structure with the insulating support into an integrated assembly. The connection bridges are pre-mounted on the insulating support, merging two separate components (connection bridge and insulator) into a single unit that is inserted as one piece, thereby simplifying the construction process while maintaining stable electrical connections.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The connection bridges are pre-positioned and fixed to the insulating support before insertion into the stator winding. This preliminary assembly ensures that the connection bridges are already in their correct positions and orientations, eliminating the instability issue during construction and reducing the complexity of on-site assembly.

Inventive Principle:
Principle #10Preliminary action

2Ease of manufacture

If rigid bars are inserted into stator slots, then electrical paths are formed, but mechanical interference occurs during insertion and bending

Engineering Contradiction:
Improveinsertion easeVSAvoidmechanical resistance
Core Design Contradiction:
Ease of manufactureVSStrength

Solution Approach 1:

The rigid bars are designed with differentiated local properties: the body portions are rigid to maintain structural integrity and electrical conductivity, while the cusps are made more flexible to facilitate insertion and bending. This local quality differentiation allows the bars to be easily inserted into stator slots without excessive mechanical resistance, while still maintaining the necessary strength for electrical connections.

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

This configuration simplifies the construction of stator windings by reducing mechanical interference and facilitating easy insertion, while ensuring stable and efficient electrical connections, thus improving the manufacturing efficiency and reducing the risk of damage to insulation.

Implementation Method 1

a series of rigid bars, which are initially shaped into a 'U' and are then axially inserted into the stator slots... the legs on the exit side are bent

Methodology Applied
Scientific EffectPlastic deformation: Plasticity

Implementation Method 2

connection bridges with plastically deformable seats simplify the coupling process by ensuring firm mechanical and electrical contact

Methodology Applied
Scientific EffectPlastic deformation: Plasticity

Data Source

PatentEP3082228B1Electric machine having a stator winding with rigid bars
Publication Date: 2019.06.05 FAB ITAL MAGNETI MARELLI SPA
  • EP3082228B1 patent drawingFigure 1
  • EP3082228B1 patent drawingFigure 2
  • EP3082228B1 patent drawingFigure 3

AI summary

An electric machine (1) provided with: a stator (5) having a magnetic core (6) longitudinally crossed by a plurality of stator slots (7); a stator winding (8) having a series of rigid bars (9), which are "U"-shaped and are inserted through the stator slots (7) defining an entry side (12), in which the cusps (11) of the "U"-shaped bars (9) are placed, and an exit side (13), in which the legs (10) of the "U"-shaped bars (9) are placed; the ends of at least two non-adjacent legs (10) are electrically connected to one another by means of a connection bridge (18; 28; 30; 32; 34) ; and an insulating support (20; 29; 31; 33; 35) is provided, which houses the connection bridge (18; 28; 30; 32; 34), is arranged under the connection bridge (18; 28; 30; 32; 34) and has a plurality of through holes (22), into which some legs are inserted (10), which have to pass through the insulating support (20; 29; 31; 33; 35) itself.