Floating Relay Power Shut-Off Unit Vibration Isolation

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Solution Overview

Problem

Existing power shut-off units in electric vehicles face issues with heavy relays causing sagging or breakage due to vibrations, leading to weight increase and structural weaknesses, making maintenance and replacement costly and inefficient.

Innovation Solution

The relay and auxiliary electronic components are arranged above a base plate, with asymmetrical bracket portions and latching members, allowing for easy inspection and replacement while reducing the load on the base plate, thereby minimizing its required strength and area, and using shock-absorbing materials to stabilize the relay.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of repair

If the relay is fixed to the upper surface of the junction box, then the relay can be easily accessed for replacement, but the heavy weight of the relay causes the base plate to sag or bend due to vibrations

Engineering Contradiction:
Improveease of relay replacementVSAvoidbase plate strength
Core Design Contradiction:
Ease of repairVSStrength

Solution Approach 1:

A support plate is introduced as an intermediary component between the relay and the base plate. The support plate bears the weight of the relay and distributes it to the side edges of the base plate, preventing the base plate from sagging or bending while still allowing easy access to the relay for replacement.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The mounting structure is segmented into multiple components: the base plate, the support plate, and the relay. The support plate is positioned at the center of the base plate and extends in the longitudinal direction, creating a separate load-bearing element that isolates the relay's weight from the base plate's main structure.

Inventive Principle:
Principle #1Segmentation

2Strength

If the base plate is thickened to prevent sagging, then the structural strength is improved, but the overall weight of the power shut-off unit increases

Engineering Contradiction:
Improvebase plate strengthVSAvoidbase plate weight
Core Design Contradiction:
StrengthVSWeight of stationary object

Solution Approach 1:

The support plate serves as a mediator that transfers the relay's weight to the side edges of the base plate. This allows the base plate to maintain its original thickness without requiring additional material, thereby preventing weight increase while still avoiding sagging or bending.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Device complexity

If the relay is mounted on the base plate, then the power shut-off unit can be compact, but vibration causes rupture or breakage of the base plate

Engineering Contradiction:
Improvestructural simplicityVSAvoidresistance to vibration
Core Design Contradiction:
Device complexityVSReliability

Solution Approach 1:

The support plate acts as a vibration-dampening intermediary between the relay and the base plate. By positioning the relay on the support plate rather than directly on the base plate, the structure becomes more resistant to vibration-induced rupture or breakage while maintaining compact dimensions.

Inventive Principle:
Principle #24Intermediary (Mediator)

Data Source

PatentEP2709222B1Power shut-off unit
Publication Date: 2019.04.24 NISSAN MOTOR CO LTD
  • EP2709222B1 patent drawingFigure 1
  • EP2709222B1 patent drawingFigure 2
  • EP2709222B1 patent drawingFigure 3~4

AI summary

The power shut-off unit is equipped with two relays (2) connected to an external circuit, and a tabular baseplate (6). Multiple auxiliary electronic components (7) are mounted on the baseplate (6). The relays (2) are held so as to float over a mounting surface (13) via a pair of retaining members (8). A distance (d) equal to or greater than the thickness of the baseplate (6) is maintained between the relays (2) and the mounting surface (13). The baseplate (6) is not directly fixed to the mounting surface (13) and is connected to the relays (2) via multiple latching members (9). Because no load is acted upon the baseplate (6) by the relays (2), the baseplate (6) can be made thin.