Engine Mount Nozzle Plate Gradient Gap for Noise and Damping
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Solution Overview
Problem
The existing nozzle plate designs for hydraulic engine mounts suffer from abnormal noise due to membrane vibration, which is exacerbated by increased dynamic characteristics and reduced damping efficiency when attempting to mitigate noise through thickness adjustments or complete membrane fixation.
Innovation Solution
A nozzle plate design featuring a membrane with a gradually increasing gap between the upper and lower nozzle plates, utilizing through holes and tapered surfaces to absorb fluid flow and minimize collisions, combined with an embedded elastic metal member for deformation, allowing for improved dynamic characteristics and noise reduction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If the thickness of the membrane engagement portion is increased to reduce clearance, then abnormal noise is reduced, but dynamic characteristics increase and NVH performance deteriorates
Solution Approach 1:
The nozzle plate is designed with non-uniform thickness distribution, where the thickness gradually decreases from the engagement portion toward the center. This creates locally different gap sizes: a small gap at the engagement portion to prevent membrane collision and abnormal noise, and larger gaps toward the center to maintain dynamic characteristics and NVH performance. This local quality variation resolves the contradiction between noise reduction and dynamic performance.
2Object-affected harmful factors
If the membrane is completely fixed to eliminate clearance, then abnormal noise is inhibited, but damping efficiency is reduced
Solution Approach 1:
The nozzle plate implements local quality differentiation through its thickness gradient design. The engagement portion maintains sufficient thickness to provide S-shaped flow path that generates damping force, while the thickness gradually decreases toward the center to create appropriate gaps. This allows the membrane to be sufficiently constrained to prevent abnormal noise while preserving the flow characteristics needed for damping efficiency.
Solution Approach 2:
The design allows the membrane to have controlled movement capability rather than complete fixation. The gradual thickness reduction creates a dynamic gap structure that permits membrane displacement during operation, maintaining the S-shaped flow path characteristics that are essential for damping efficiency while still preventing excessive collision that causes abnormal noise.
3Strength
If the thickness of the nozzle plate is uniformly increased, then structural strength is improved, but fluid flow absorption capability is reduced
Solution Approach 1:
The nozzle plate employs non-uniform thickness distribution where the engagement portion has sufficient thickness for structural strength and collision prevention, while the thickness gradually decreases toward the center. This creates larger gaps in the central region that enhance fluid flow absorption capability and maintain S-shaped flow characteristics, resolving the contradiction between structural strength and fluid flow absorption.
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 effectively inhibits abnormal noise while maintaining or enhancing NVH performance and damping efficiency by gradually increasing the gap between the membrane and nozzle plates, reducing collision impact and improving fluid flow absorption.
Implementation Method 1
a hydraulic liquid is encapsulated and flows between an upper liquid chamber and a lower liquid chamber through a flow path formed in the nozzle plate
Implementation Method 2
the hydraulic liquid flows through the flow path so as to generate a relatively high damping value
Implementation Method 3
The membrane 6, which vibrates when the hydraulic liquid flows
Implementation Method 4
the membrane vibrates, thereby generating a damping value
Implementation Method 5
the insulator 2 is elastically deformed, and thus a volume of the upper liquid chamber is changed
Data Source
AI summary
A nozzle plate of an engine mount may a lower nozzle plate which has a flow path groove formed in an upper surface, and a lower opening hole that communicates with the lower liquid chamber; an upper nozzle plate which is coupled to the lower nozzle plate so as to cover an upper side of the flow path groove and form a flow path, and has an upper opening hole that communicates with the upper liquid chamber; and a membrane which is mounted such that a rim portion thereof is engaged between the lower nozzle plate and the upper nozzle plate, and upper and lower surfaces thereof are exposed through the upper opening hole and the lower opening hole, respectively.