Bus-Bar Holder Rib Structure for Compact EPS Motor Assembly

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Solution Overview

Problem

The existing electric rotating machine apparatus requires additional protruding portions and increased through holes to accommodate bus bars and circuit boards, leading to enlarged components and increased costs, hindering downsizing and cost-saving efforts in both the electric rotating machine and power steering systems.

Innovation Solution

The electric rotating machine apparatus eliminates the need for additional protruding portions by using a bus-bar holder with a columnar portion and ribs that penetrate through holes in both the circuit board and bus bar, allowing for compact integration without sacrificing mounting area for wiring leads and electronic components.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If additional protruding portions are provided in the bus-bar holder to accommodate both the bus bar and circuit board, then both components can be held, but the bus-bar holder becomes enlarged and the total board area increases

Engineering Contradiction:
Improveability to hold both bus bar and circuit boardVSAvoidtotal board area
Core Design Contradiction:
Adaptability or versatilityVSArea of stationary object

Solution Approach 1:

The single protruding portion is designed to perform multiple functions: it holds both the bus bar (via the through hole) and the circuit board (via the mounting hole), eliminating the need for separate protruding portions for each component. This multi-functional design resolves the contradiction by maintaining adaptability while reducing the overall area of the bus-bar holder.

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

Solution Approach 2:

The patent merges the functions of holding the bus bar and circuit board into a single integrated protruding portion structure. By combining these two separate holding functions into one component, the total area required is reduced compared to having separate protruding portions, while still achieving both holding objectives.

Inventive Principle:
Principle #5Merging (Combining)

2Ease of operation

If multiple through holes are provided in the circuit board for different protruding portions, then components can be assembled, but the mounting area for wiring leads and electronic components decreases

Engineering Contradiction:
Improveassembly capabilityVSAvoidmounting area for wiring leads and electronic components
Core Design Contradiction:
Ease of operationVSArea of stationary object

Solution Approach 1:

The single protruding portion serves dual purposes: accommodating the bus bar through its through hole and mounting the circuit board via its mounting hole. This eliminates the need for multiple separate protruding portions and their associated through holes, thereby preserving more area on the circuit board for wiring leads and electronic components while maintaining full assembly capability.

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

3Adaptability or versatility

If the bus-bar holder is enlarged to accommodate additional protruding portions, then more components can be held, but the cost of the electric rotating machine increases

Engineering Contradiction:
Improvecomponent holding capacityVSAvoidmanufacturing cost
Core Design Contradiction:
Adaptability or versatilityVSEase of manufacture

Solution Approach 1:

By designing a single protruding portion that can hold both the bus bar and circuit board, the bus-bar holder maintains its original compact size rather than being enlarged. This multi-functional approach reduces material usage and manufacturing complexity, thereby lowering costs while still achieving the capacity to hold multiple components.

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

Solution Approach 2:

The patent eliminates the need for additional protruding portions and their associated materials. By discarding the redundant structures and recovering the space and materials, the overall manufacturing cost is reduced while maintaining the necessary component holding capacity.

Inventive Principle:
Principle #34Discarding and recovering

Data Source

PatentEP4199314B1Rotating electric machine device and electric power steering device
Publication Date: 2024.09.11 MITSUBISHI ELECTRIC CORP
  • EP4199314B1 patent drawingFigure 1
  • EP4199314B1 patent drawingFigure 2
  • EP4199314B1 patent drawingFigure 3

AI summary

The objective of the present disclosure is to dispense with any additional protruding portion to be provided at a time when a control circuit board (14) is assembled to a bus-bar holder (61) holding a bus bar (38), to realize downsizing of the bus-bar holder (61), and then to downsize an electric rotating machine apparatus (100) and an electric power steering apparatus (150). In a first protruding portion (611) of the bus-bar holder (61), there are provided a columnar portion (611a), two or more first ribs (611c) that are provided on an outer circumferential surface of the columnar portion (611a) in such a way as to be parallel with a center axis of the columnar portion (611a) and in such a way as to be spaced apart from one another, and two or more second ribs (611b); the first rib (611c) makes contact with an inner circumference surface of a first through hole (143) of the control circuit board (14); the second rib (611b) makes contact with an inner circumference surface of a second through hole (381) of the bus bar (38).