Hydraulic Mount Membrane Crests Valleys Rattle Noise
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Solution Overview
Problem
Conventional hydraulic mounts for vehicles fail to effectively reduce rattle noise due to membrane excitation and pressure variations, leading to noise issues from nozzle hitting during vibration excitation.
Innovation Solution
A hydraulic mount design featuring a cylinder-type membrane with a pattern of crests and valleys, which redirects the membrane's movement perpendicular to the excitation direction, delaying nozzle hits and distributing collision forces to reduce rattle noise by sequential contact with nozzle plates.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If a conventional hydraulic mount uses a flat membrane structure, then the fluid can move freely between chambers, but the membrane gets excited by pressure variations causing nozzle hitting and rattle noise
Solution Approach 1:
The patent applies curvature to the membrane by forming crests and valleys on its surface. This curved structure redirects the membrane's movement perpendicular to the excitation direction, preventing the membrane from directly contacting the nozzle and eliminating rattle noise while maintaining fluid movement capability.
Solution Approach 2:
The patent introduces a new dimension of movement by creating crests and valleys that cause the membrane to move not only in the vertical direction (parallel to excitation) but also in the radial direction (perpendicular to excitation). This multi-dimensional movement pattern prevents direct nozzle contact while maintaining fluid communication between chambers.
2Object-affected harmful factors
If the membrane is made more rigid to prevent excitation, then noise is reduced, but the hydraulic mount loses its ability to absorb vibrations effectively
Solution Approach 1:
The patent makes the membrane dynamically responsive by creating a crested structure that adapts its movement pattern based on the excitation direction. The membrane remains flexible and capable of vibration absorption while its crested geometry dynamically redirects movement perpendicular to excitation, preventing noise-generating nozzle contact.
Solution Approach 2:
The patent changes the geometric parameters of the membrane by introducing crests and valleys, which alters the membrane's movement characteristics without changing its material properties. This allows the membrane to maintain flexibility for vibration absorption while changing its effective stiffness and movement direction to prevent noise.
3Adaptability or versatility
If the membrane is made flexible to absorb vibrations, then vibration reduction is improved, but the membrane becomes more susceptible to excitation and nozzle hitting
Solution Approach 1:
The crested geometry of the flexible membrane redirects its natural movement perpendicular to the excitation direction. This curvature allows the membrane to remain flexible for vibration absorption while preventing the flat-surface nozzle contact that causes rattle noise.
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 reduces rattle noise by delaying nozzle hits and distributing collision forces, improving Noise, Vibration & Harshness (NVH) characteristics during both large and small displacement vibrations.
Implementation Method 1
the fluid of the upper fluid chamber 22 may absorb the small displacement vibration while moving toward the lower fluid chamber 24 side through the nozzle portion 30
Implementation Method 2
the main rubber 14 is compressed and simultaneously, the nozzle portion 30 becomes a closing status by pressing the membrane 26
Data Source
AI summary
A hydraulic mount for a vehicle includes: a core bush coupled to a bolt; a main rubber formed on an outer surface of the core bush; an orifice portion coupled to a lower portion of the main rubber to divide an upper fluid chamber and a lower fluid chamber; and a lower rubber film coupled to a lower portion of the orifice portion. The orifice portion includes an upper nozzle plate formed with a first fluid inlet and outlet port, a lower nozzle plate formed with a fluid path and a second fluid inlet and outlet port, and a cylinder-type membrane vertically arranged between the upper nozzle plate and the lower nozzle plate, and a pattern of crests and valleys is formed along a circumference of the membrane, the pattern of crests and valleys selectively contacting the upper nozzle plate and the lower nozzle plate.