EV Powertrain Suspension Bushing Structure for High-Frequency NVH
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Solution Overview
Problem
Existing suspension bushings for electric vehicles face high-frequency dynamic hardening, leading to reduced vibration isolation capacity and potential high-frequency noise, especially with high motor torque and excitation frequencies, and existing solutions either compromise stiffness or introduce noise issues.
Innovation Solution
A suspension bushing design featuring a mandrel, outer sleeve, and a rubber mainspring with multiple main parts and extending parts forming stepped structures, connected by inner and outer connecting rings, which reduces high-frequency dynamic stiffness and maintains compact size, preventing high-frequency noise.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If existing suspension bushings are used, then the structure is simple, but the high-frequency dynamic stiffness increases sharply, reducing vibration isolation capacity
Solution Approach 1:
The rubber mainspring is divided into multiple main parts (first main part, second main part, third main part) arranged around the mandrel at intervals. This segmentation allows each part to independently deform and absorb high-frequency vibrations, reducing overall dynamic stiffness while maintaining structural simplicity. The segmented design enables better vibration isolation performance without complicating the overall bushing structure.
Solution Approach 2:
The patent introduces extending parts that extend in the axial direction from the main parts, creating a stepped structure. This dimensional extension increases the effective vibration isolation path length without significantly increasing the radial size, allowing the bushing to maintain compact dimensions while improving high-frequency vibration isolation capacity through the additional deformation path.
2Reliability
If a vibration absorption layer is added to reduce dynamic stiffness, then vibration isolation performance improves, but high-frequency noise risk increases
Solution Approach 1:
The patent uses a composite structure combining rubber material for the mainspring with metal components (mandrel, outer sleeve, connecting rings). The rubber material provides vibration isolation through its viscoelastic properties, while the metal components provide structural support. This composite approach achieves vibration isolation performance without relying on additional vibration absorption layers that could generate noise, as the rubber itself serves as both the structural element and the vibration isolating element.
3Reliability
If the suspension structure is made lightweight with high modality, then NVH performance improves, but not all suspension points can accommodate such structures
Solution Approach 1:
The bushing design with segmented rubber mainspring and connecting rings creates a universal structure that can be applied to various suspension points. The modular design with inner and outer connecting rings allows the same basic structure to accommodate different mounting configurations and suspension geometries. The extending parts can be positioned to match different suspension point requirements, making the design universally applicable while maintaining good NVH performance through reduced high-frequency dynamic stiffness.
4Reliability
If extending parts are added to reduce high-frequency dynamic stiffness, then vibration isolation improves, but the size of the rubber mainspring may increase
Solution Approach 1:
The extending parts are strategically positioned only at specific locations where they can most effectively reduce high-frequency dynamic stiffness, rather than uniformly increasing the size of the entire rubber mainspring. The stepped structure created by the extending parts focuses the vibration isolation function in critical areas while maintaining compact overall dimensions. This localized approach allows vibration isolation improvement without proportionally increasing the volume of the rubber mainspring.
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 design enhances vibration isolation performance while maintaining structural stability and compactness, allowing application to various suspension systems without increasing size or noise risk.
Implementation Method 1
the dynamic stiffness of suspension will be increased sharply in case of a high frequency, thus drastically reducing the vibration isolation capacity of the suspension bushings
Implementation Method 2
a rubber mainspring connected between the mandrel and the outer sleeve. The rubber mainspring comprises multiple main parts disposed around an outer contour of the mandrel at intervals
Data Source
AI summary
A suspension bushing for a powertrain of an electric vehicle includes a mandrel, an outer sleeve and a rubber mainspring connected between the mandrel and the outer sleeve. The rubber main spring includes multiple main parts arranged at intervals and surrounding the outer contour of the mandrel. At least one side of each of the main parts is provided with an extending part. An end surface of the extending part and an end surface of each main part form a stepped structure.