Engine Accessory Bracket as a Dynamic Damper for Front-Rear Vibration

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Solution Overview

Problem

Existing engine accessory mounting structures fail to effectively reduce vibrations in the direction orthogonal to the crankshaft's horizontal plane without increasing weight and cost, as they either focus on up-down vibrations or require reinforcement.

Innovation Solution

An accessory mounting structure featuring a bracket with a first portion connected to the engine and a second portion connected to the accessory, where the second portion has lower rigidity and functions as a dynamic damper, vibrating in an opposite phase to attenuate engine vibrations in the front-rear direction.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Object-affected harmful factors

If reinforcement is used to reduce engine vibration in the front-rear direction, then vibration reduction is achieved, but weight and cost increase

Engineering Contradiction:
Improveengine vibration in front-rear directionVSAvoidweight
Core Design Contradiction:
Object-affected harmful factorsVSWeight of moving object

Solution Approach 1:

The patent applies mechanical vibration principle by designing the second portion of the bracket to vibrate in opposite phase to the engine vibration, creating a dynamic damper effect that attenuates engine vibration in the front-rear direction without requiring structural reinforcement

Inventive Principle:
Principle #18Mechanical vibration

Solution Approach 2:

The patent changes the rigidity parameter of the bracket by making the second portion have lower rigidity than the first portion, enabling it to function as a dynamic damper that vibrates in opposite phase to reduce engine vibration without increasing overall structure weight

Inventive Principle:
Principle #35Parameter changes

2Object-affected harmful factors

If reinforcement is used to reduce engine vibration in the front-rear direction, then vibration reduction is achieved, but cost increases

Engineering Contradiction:
Improveengine vibration in front-rear directionVSAvoidcost
Core Design Contradiction:
Object-affected harmful factorsVSEase of manufacture

Solution Approach 1:

The patent uses mechanical vibration to create a dynamic damper effect through the bracket's second portion, which vibrates in opposite phase to attenuate engine vibration, replacing the need for expensive reinforcement structures

Inventive Principle:
Principle #18Mechanical vibration

Solution Approach 2:

By changing the rigidity parameter of the second portion to be lower than the first portion, the patent enables vibration-based vibration reduction at lower manufacturing cost compared to reinforcement approaches

Inventive Principle:
Principle #35Parameter changes

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 effectively reduces engine vibrations in the front-rear direction without increasing weight or cost by utilizing the dynamic damper effect of the lower rigidity second portion, eliminating the need for reinforcement.

Implementation Method 1

The second portion functions as a dynamic damper that attenuates vibration of the engine by vibrating in an opposite phase to the vibration of the engine

Methodology Applied
Scientific EffectDynamic damper: Tuned Mass Damper

Data Source

PatentEP3578777B1Accessory mounting structure for engine
Publication Date: 2021.05.05 MAZDA MOTOR CORP
  • EP3578777B1 patent drawingFigure 1
  • EP3578777B1 patent drawingFigure 2
  • EP3578777B1 patent drawingFigure 3

AI summary

An accessory mounting structure of an engine 1 includes a crankshaft 2 that extends in a first direction. The engine 1 supports an accessory 7 via a bracket 8. The bracket 8 includes a first portion 16 connected to the engine 1, and a second portion 17 connected to the accessory 7 and having a lower rigidity than the first portion 16. The second portion 17 functions as a dynamic damper that attenuates vibration of the engine 1 by vibrating in an opposite phase to the vibration of the engine 1 and in the first direction when the engine 1 vibrates in a second direction orthogonal to the first direction on a horizontal plane.