Motor Mount Rubber Leg Layout to Suppress Surging and Strain
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing tubular vibration-damping devices for motor mounts in electrified vehicles face issues with deterioration of vibration damping performance due to rubber leg surging, limited durability, and restricted freedom in tuning spring characteristics, particularly in high-frequency ranges.
Innovation Solution
A tubular vibration-damping device with rubber legs arranged on the lower side of the inner shaft member, featuring vertical extensions with axial projections, and a compression-focused design that includes a stopper mechanism to limit displacement and distribute strain, enhancing durability and tuning freedom.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a mass projection is provided to the elastic leg to suppress surging by resonance, then vibration damping performance is improved, but strain is concentrated around the mass projection which limits durability
Solution Approach 1:
A stopper mechanism is introduced as an intermediary component between the inner shaft member and outer tube member. This stopper prevents excessive relative displacement and limits the deformation range of the rubber legs, thereby preventing strain concentration around the mass projection while maintaining the vibration damping effect. The stopper acts as a mediator that protects the rubber leg from overload conditions.
Solution Approach 2:
The stopper mechanism provides beforehand cushioning by limiting the maximum displacement of the inner shaft member relative to the outer tube member. By pre-establishing this displacement limit, the system prevents excessive strain from developing in the rubber legs during vibration events, thus protecting the mass projection area from strain concentration before it occurs.
2Adaptability or versatility
If the bonded surfaces of the elastic leg to the inner tube and outer tube are remote from each other, then the elastic leg undergoes shear deformation over a wide area which provides tuning freedom, but the amount of deformation increases which may affect durability
Solution Approach 1:
The invention changes the geometric parameters of the rubber leg structure, specifically the distance between bonded surfaces and the cross-sectional area distribution. By optimizing these parameters, the rubber leg can undergo sufficient shear deformation for tuning freedom while the stopper mechanism ensures the total deformation remains within durable limits.
Solution Approach 2:
The rubber leg is designed with non-uniform cross-sectional area distribution, creating local quality variations. The cross-sectional area is larger at the bonded surfaces and tapers toward the middle, which concentrates the deformation in specific regions while maintaining overall structural integrity and preventing excessive total deformation.
3Device complexity
If two rubber legs are provided below the inner shaft member, then the structure is simplified, but the vibration damping performance may deteriorate due to surging of the rubber legs
Solution Approach 1:
Mass projections are provided on the rubber legs to utilize mechanical vibration and resonance effects. These mass projections create localized resonance that suppresses unwanted surging of the rubber legs, thereby maintaining effective vibration damping performance despite the simplified two-leg structure.
Solution Approach 2:
The stopper mechanism serves as an intermediary that prevents excessive vibration and surging of the rubber legs. By limiting the relative displacement between the inner shaft member and outer tube member, the stopper ensures that the simplified two-leg structure maintains reliable vibration damping performance without deteriorating due to uncontrolled surging.
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
The solution effectively suppresses rubber leg surging, improves durability, and allows for better vibration damping performance, particularly in high-frequency ranges, contributing to enhanced quietness and ride comfort.
Implementation Method 1
it is disclosed in US 2008/0258364 A1 that a mass projection projecting in the axial direction is provided to the elastic leg, and that the surging of the elastic leg is suppressed by resonance of the mass projection
Implementation Method 2
the elastic legs undergo shear deformation over a wide area during vibration input
Implementation Method 3
two rubber legs extending between opposed faces of the inner shaft member and the outer tube member while connecting the inner shaft member and the outer tube member
Data Source
AI summary
A tubular vibration-damping device for a motor mount including an inner shaft member, an outer tube member, and two rubber legs extending between opposed faces of the inner shaft member and the outer tube member while connecting them. Both the rubber legs are arranged on a lower side of the inner shaft member that is a compression side during input of a principal load, and extend vertically at positions that are remote from each other in a left-right direction. Each rubber leg includes a connecting rubber part that is vertically continuous and directly connects the opposed faces of the inner shaft member and the outer tube member. Each rubber leg includes a rubber projection protruding in an axial direction. The rubber projection is arranged to be located on a left-right inside of a left-right outer edge of the connecting rubber part.