Engine Mount Nozzle Plate Semifixed Membrane Noise Control
Solution Overview
Problem
The existing hydraulic engine mount nozzle plate designs 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 thicker membrane engagement or complete fixation.
Innovation Solution
A nozzle plate design featuring a lower stepped portion, seating portion, protrusion, and stopper mechanism that allows hydraulic liquid flow through specific gaps under varying pressure conditions, with optional slits and rib structures for membrane deformation and durability, combining semifixed and integrated membrane advantages to enhance dynamic characteristics and NVH performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If the thickness of the portion where the membrane is engaged is increased to reduce abnormal noise, then abnormal noise is reduced, but dynamic characteristics are increased and NVH performance deteriorates
Solution Approach 1:
The patent applies the dynamics principle by designing a semifixed membrane structure where the membrane is engaged between the upper and lower nozzle plates but not completely fixed. This allows the membrane to have controlled mobility - it can vibrate to some extent to maintain dynamic characteristics and NVH performance, while the engagement structure limits excessive vibration to reduce abnormal noise. The membrane's partial fixation creates a dynamic balance between noise reduction and performance maintenance.
Solution Approach 2:
The patent changes the engagement parameter of the membrane by optimizing the thickness and engagement structure between the nozzle plates. Instead of increasing thickness excessively, the patent finds an optimal engagement parameter that provides sufficient constraint to reduce abnormal noise while maintaining the membrane's dynamic characteristics. This parameter optimization resolves the contradiction between noise reduction and performance preservation.
2Object-affected harmful factors
If the membrane is completely fixed to eliminate clearance and reduce abnormal noise, then abnormal noise is reduced, but damping efficiency is reduced
Solution Approach 1:
The patent applies partial action by implementing a semifixed membrane structure rather than complete fixation. The membrane is partially constrained by engagement between the nozzle plates, which is sufficient to eliminate abnormal noise caused by excessive clearance, but not so constrained as to completely prevent the membrane's damping function. This partial constraint approach achieves noise reduction while preserving damping efficiency.
Solution Approach 2:
The semifixed membrane structure maintains dynamic characteristics by allowing controlled movement. The membrane can still vibrate and deform to provide damping efficiency, while the engagement structure prevents excessive clearance that causes abnormal noise. This dynamic balance resolves the contradiction between noise reduction and damping efficiency.
3Object-affected harmful factors
If the clearance is reduced by increasing membrane engagement thickness, then abnormal noise is reduced, but NVH performance deteriorates
Solution Approach 1:
The patent optimizes the engagement thickness parameter to achieve an optimal balance. By carefully selecting the engagement thickness, the patent reduces clearance enough to eliminate abnormal noise while maintaining the membrane's dynamic characteristics and NVH performance. This parameter optimization resolves the contradiction between noise reduction and performance preservation.
Solution Approach 2:
The semifixed engagement structure provides dynamic constraint rather than rigid fixation. This allows the membrane to maintain its dynamic characteristics and NVH performance while the engagement structure sufficiently reduces clearance to eliminate abnormal noise. The dynamic nature of the engagement resolves the contradiction between noise reduction and performance maintenance.
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 and improves damping performance by controlling hydraulic liquid flow based on engine or travel states, maintaining dynamic characteristics and reducing noise without compromising NVH performance.
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 hydraulic liquid flows through a gap formed at a portion where the membrane is engaged... the membrane vibrates, thereby generating a damping value
Implementation Method 4
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 include a lower nozzle plate, an upper nozzle plate, a membrane, and a stopper, in which a flow of the hydraulic liquid is allowed through a gap formed between the stopper and the membrane and a gap formed between the membrane and a seating portion of the lower nozzle plate when pressure of the hydraulic liquid applied to the membrane is relatively low, and a flow of the hydraulic liquid is blocked as the membrane comes into close contact with the stopper or the seating portion when pressure of the hydraulic liquid is relatively high.