Strut Top Mount MCU Isolator Travel Limiter
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Solution Overview
Problem
Microcellular urethane (MCU) used in suspension components like top mounts is prone to damage under high loads, causing irreversible changes in spring and damping rates, making it unsuitable for vehicles that experience heavy impacts from rough roads or off-road use, despite providing a desirable combination of spring and damping rates under normal conditions.
Innovation Solution
The design incorporates an integral travel limiter made of stiffer materials like rubber or rubber blends, which acts in parallel with the MCU isolator to prevent overloading by increasing the spring rate and limiting excessive displacement under high loads, ensuring the MCU isolator maintains its desired characteristics.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a soft resilient material is used to achieve desired spring and damping rate, then the spring rate and damping rate are within specified range, but the durability is compromised
Solution Approach 1:
The patent uses a composite structure combining MCU isolator with microcellular structure (providing softness and damping) and solid filler material or reinforcement (providing strength). This composite approach allows the material to exhibit both the desired spring/damping characteristics and the durability needed to withstand high loads without irreversible damage.
2Ease of operation
If MCU composition is optimized for normal suspension inputs, then the spring and damping rates are desirable under normal conditions, but the component cannot tolerate higher loads from rough roads or off-road use
Solution Approach 1:
The patent applies different material properties to different regions or aspects of the isolator. The MCU provides the primary isolation function for normal vibrations, while embedded reinforcements or a composite structure provides localized strength where high loads occur, allowing each region to perform its specific function optimally.
Solution Approach 2:
The patent designs the isolator with pre-reinforced structures or protective elements that engage before the MCU material can be damaged by excessive loads. These protective features act in advance to prevent the harmful compression that would otherwise irreparably damage the soft MCU material during extreme events.
3Device complexity
If the top mount uses a solid structure, then the structure is simple and durable, but NVH isolation and suspension tuning capability are insufficient
Solution Approach 1:
The patent employs MCU (microcellular urethane) material which has a controlled porous or cellular structure. This porous structure provides excellent vibration isolation and NVH performance by dissipating energy through the cell walls, while still maintaining a relatively simple overall component structure that can be molded as a single piece.
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 solution enhances the durability and maintains the desired spring and damping rates of the top mount by preventing excessive loading on the MCU isolator, allowing it to perform effectively under both normal and high-load conditions.
Implementation Method 1
The resilient material acts as both a spring and a damper between the plate and the housing
Implementation Method 2
The resilient material acts as both a spring and a damper between the plate and the housing
Implementation Method 3
A travel limiter is disposed in the housing and has a first body of resilient material disposed between the member and the top end of the housing
Data Source
AI summary
A top mount for a suspension damper has a housing with an interior chamber and a damper attachment member disposed in the interior chamber and spaced from the top end and the bottom end. An isolation assembly, formed of MCU, has an upper portion disposed between the member and the top end of the housing and a lower portion disposed between the member and the bottom end of the housing such that the isolation assembly supports the member in the housing. A travel limiter is disposed in the housing and has a first body of resilient material disposed between the member and the top end of the housing and a second body of material disposed between the member and the bottom end of the housing. The isolation assembly is disposed so as to function in parallel to the travel limiter.