Hydraulic Mount Membrane Spring Design for NVH Noise Control
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Solution Overview
Problem
Conventional hydraulic mounts with semi-fixed membranes suffer from degradation-induced sludge formation, which impairs dynamic characteristics and generates rattle noise due to the interaction between the membrane and steel plates.
Innovation Solution
A hydraulic mount design featuring a disc-shaped membrane with a ring-shaped spring that includes upper and lower ribs with a herringbone pattern, made of plastic, which absorbs membrane expansion and converts vertical vibrations into rotational energy, preventing sludge accumulation and reducing rattle noise.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a steel plate is provided in the membrane to secure the loss factor, then the membrane can be fixed in the mounting recess, but the steel plate strikes the upper plate and nozzle plate during vibration, generating rattle noise
Solution Approach 1:
The harmful steel plate is completely removed from the membrane structure. Instead of using a steel plate for fixation, the patent employs a rubber-based membrane with a specific mounting structure that achieves both fixation and vibration damping without rigid components that cause noise
Solution Approach 2:
The membrane is designed as a flexible rubber structure with optimized thickness and material properties. The rubber material provides both the necessary flexibility for vibration absorption and sufficient structural integrity for fixation, replacing the rigid steel plate approach
2Strength
If the membrane is made of rubber to provide elasticity, then it can dampen high frequency vibration, but the rubber expands due to degradation and produces sludge that blocks the hydraulic liquid flow path
Solution Approach 1:
The membrane is pre-mounted in a compressed state within the mounting recess, creating initial contact pressure between the membrane edge and the recess walls. This preliminary compression counteracts future expansion from degradation, preventing sludge accumulation and flow path blockage
Solution Approach 2:
The mounting recess structure provides a cushioning effect by constraining the membrane edges. The recess walls absorb the expansion force from rubber degradation before it can affect the hydraulic flow path, protecting the system from sludge-related failures
3Object-affected harmful factors
If the membrane is vibrated up and down to dampen high frequency vibration, then NVH performance is improved, but the vertical vibration generates impact forces that cause rattle noise
Solution Approach 1:
The mounting structure allows the membrane to vibrate primarily in the vertical dimension for damping purposes, while the inclined ribs and mounting geometry convert some of this vertical motion into rotational or lateral movement. This dimensional transformation reduces the impact forces that cause rattle noise while maintaining vibration damping effectiveness
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 suppresses sludge generation and rattle noise by dispersing vertical vibrations through rotational movement, maintaining NVH performance and preventing sludge accumulation in the mounting recess.
Implementation Method 1
a spring (20) made of a plastic material having a predetermined elasticity
Implementation Method 2
the membrane (10) is vibrated up and down
Implementation Method 3
induces a rotation, thus further improving noise, vibration, harshness (NVH) performance
Implementation Method 4
a hydraulic mount filled with liquid to dampen vibration using viscosity resistance to a liquid flow
Implementation Method 5
the insulator 300 made of a material such as synthetic rubber or synthetic resin to have elasticity repeats elastic compression or restoration according to a change in load and vibration of the engine
Data Source
AI summary
A hydraulic mount having an upper liquid chamber defined above a nozzle plate mounted therein and a lower liquid chamber defined below the nozzle plate, and configured such that hydraulic liquid filled therein flows through a path defined in the nozzle plate to the upper and lower liquid chambers may include a disc-shaped membrane, and a spring having a shape of a ring into which an edge of the membrane is fitted, and mounted in a mounting recess that is formed in the nozzle plate, in which the spring includes a body portion to which the membrane is fastened, an upper ring portion provided above the body portion, and a lower ring portion provided below the body portion.