Stator Bus Bar Unit Segmented Overlapping Design

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Solution Overview

Problem

Current motor designs, particularly in stators and bus bar units, lack a minimalist structure, leading to inefficiencies in material usage and potential for miniaturization, which is essential for reducing costs and enhancing performance in applications like power steering devices.

Innovation Solution

A stator with a ring-shaped core and twelve elemental teeth parts, where coils are formed in pairs connected by conductive lines, and a bus bar unit with overlapping semicircular and minor arc-shaped bus bars arranged in phase and neutral regions, respectively, to simplify wire connections and reduce material usage.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a conventional bus bar unit structure is used with multiple wiring boards arranged perpendicularly, then the motor can operate reliably, but the structure becomes complex and material usage increases

Engineering Contradiction:
Improvemotor operation reliabilityVSAvoidbus bar unit structure complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The bus bar unit is segmented into multiple bus bars (first bus bar, second bus bar, third bus bar, fourth bus bar) with distinct functional regions (phase region and neutral region). Each bus bar serves specific connection purposes, allowing the complex wiring function to be divided into manageable segments rather than using a monolithic complex structure

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The bus bars are arranged in different spatial dimensions and orientations. The first bus bar extends in one direction while the second, third, and fourth bus bars extend in different directions, utilizing three-dimensional space efficiently. This dimensional arrangement achieves reliable connections without requiring multiple perpendicular wiring boards, thus reducing structural complexity

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

2Reliability

If more material is used in bus bar unit construction, then connection reliability is improved, but material expenses and device size increase

Engineering Contradiction:
Improveconnection reliabilityVSAvoidmaterial usage
Core Design Contradiction:
ReliabilityVSQuantity of substance

Solution Approach 1:

Different regions of the bus bar unit are assigned different functional qualities. The phase region contains bus bars for phase connections (second, third, fourth bus bars), while the neutral region contains the first bus bar for neutral connections. This local differentiation ensures material is placed only where needed for specific electrical functions, avoiding unnecessary material usage while maintaining connection reliability

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The bus bar unit structure serves multiple functions simultaneously: it provides electrical connections for all three phases, establishes neutral point connections, and organizes wiring in a compact arrangement. The overlapping arrangement of bus bars achieves multiple connection objectives within a single integrated structure, reducing the total quantity of material needed compared to conventional separate wiring boards

Inventive Principle:
Principle #6Universality (Multi-functionality)

3Power

If the stator and bus bar unit are designed with traditional configurations, then the motor meets performance specifications, but miniaturization is limited

Engineering Contradiction:
Improvemotor performanceVSAvoidmotor size
Core Design Contradiction:
PowerVSVolume of moving object

Solution Approach 1:

The bus bar unit is merged with the stator structure in a integrated assembly. The bus bars are positioned to overlap with each other and connect to coil groups directly, eliminating the need for separate wiring boards and reducing overall motor volume. This merging achieves compact design without compromising power performance

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The bus bars utilize three-dimensional spatial arrangement with overlapping configurations in different directions. This dimensional utilization allows the electrical connections to be made within a compact volume, enabling motor miniaturization while maintaining all necessary connection functions for full power performance

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

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 allows for the miniaturization of motors and reduction in material expenses while maintaining efficient operation, enabling better performance in power steering devices by simplifying the stator and bus bar unit designs.

Implementation Method 1

a 14 electrode-12 slot brushless motor which forms a rotating magnetic field by a three-phase coil group consisting of a U-phase, a V-phase and a W-phase

Methodology Applied
Scientific EffectElectromagnetic induction: Electromagnetic Induction

Data Source

PatentEP2400635B1Stator, bus bar unit, motor, and power steering device
Publication Date: 2019.01.09 NIDEC CORP(JP)
  • EP2400635B1 patent drawingFigure 1
  • EP2400635B1 patent drawingFigure 2
  • EP2400635B1 patent drawingFigure 3

AI summary

A stator (1) comprises a core (2) and a coil group. The core (2) has a ring part (21) in a form of a ring, and a teeth part (22) consisting of twelve elemental teeth parts (22a) projecting from the inside of the ring part (21) toward the center thereof. The coil group consists of twelve coils (4) formed in each of the elemental teeth parts (22a). The core (2) is formed by coupling twelve elemental cores (2a) which respectively have an elemental teeth part (22a). The coil group is constituted of six coil pairs (40) each consisting of two coils (4) joined to each other by a single conductive line. When the core (2) is divided into a phase region (27) and a neutral region (28) equally along the axial direction, one coils (4) in each of the six coil pairs (40) are arranged in the phase region (27), and the other coils (4) are arranged in the neutral region (28).