Hydraulic Mount Membrane Groove Design for Rattle Noise Reduction
Solution Overview
Problem
Conventional hydraulic mounts for vehicles experience disruptive rattle noise due to membrane excitation and surface contact during large displacement vibrations, which is not effectively addressed by existing designs.
Innovation Solution
The hydraulic mount design increases the exposed area of the membrane through a line-contact structure with concave groove portions on the upper plate, allowing for improved contact between the membrane and nozzle portion, minimizing rattle noise while maintaining optimal vibration reduction performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If the membrane contact area with the nozzle portion is increased to reduce rattle noise, then the rattle noise is reduced, but the exposed area of the membrane toward the upper fluid chamber decreases, reducing fluid operation effectiveness
Solution Approach 1:
The patent introduces a vertical dimension by forming a groove on the inner diameter surface of the upper plate, creating a stepped structure that allows the membrane to have different exposure levels. This dimensional change enables the membrane to maintain sufficient exposed area toward the upper fluid chamber while also increasing contact area with the nozzle portion through the groove structure, thereby resolving the contradiction between noise reduction and fluid operation effectiveness.
2Stability of the object's composition
If the membrane is fully covered by the upper plate to increase structural stability, then structural stability is improved, but the membrane cannot effectively operate fluid and absorb vibrations
Solution Approach 1:
The upper plate is segmented by forming a groove on its inner diameter surface, dividing the contact area into different zones. This segmentation allows part of the membrane to remain exposed for effective fluid operation and vibration absorption, while another part contacts the nozzle portion through the groove structure for structural stability and noise reduction, thus resolving the contradiction between stability and productivity.
3Productivity
If the membrane is allowed to move freely to improve vibration absorption, then vibration absorption is improved, but rattle noise increases due to membrane excitation and collision
Solution Approach 1:
The patent applies local quality by creating a groove structure at a specific location on the inner diameter surface of the upper plate. This localized structural modification allows the membrane to have restricted contact with the nozzle portion in the groove area, reducing rattle noise from free movement, while maintaining sufficient exposed area for effective vibration absorption, thus resolving the contradiction between vibration absorption and noise reduction.
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 increased membrane exposure area enhances fluid operation and absorption of idle vibrations, and the line-contact structure effectively reduces rattle noise during large displacement vibrations, improving overall Noise, Vibration & Harshness (NVH) performance.
Implementation Method 1
when a large displacement vibration (e.g., driving on a bumpy road) is input to the hydraulic mount configured in the manner described above, as illustrated in the right side of the accompanying FIG. 2, the main rubber 14 is compressed and simultaneously, the nozzle portion 30 becomes a closing status by pressing the membrane 26; simultaneously, while the fluid within the upper fluid chamber 22 enters into the fluid path 18-1 of the lower plate 18 through the upper inlet and outlet port 16-1 formed on the upper plate 16 of the orifice portion 20, and then is filled into the lower fluid chamber 24 through the lower inlet and outlet port 18-2 formed on a predetermined position of the fluid path, the high reduction absorbing the large displacement vibration is implemented.
Implementation Method 2
when a small displacement vibration (e.g., driving on a smooth road) is input to the hydraulic mount, as illustrated in the left side of the accompanying FIG. 2, 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 to thereby obtain an improved effect of Noise, Vibration & Harshness (NVH).
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 so as to divide an upper fluid chamber and a lower fluid chamber, the orifice portion including a lower plate and an upper plate; and a membrane mounted between the lower plate and the upper plate. A fluid path is formed on an upper surface portion of the lower plate, a lower inlet and outlet port is formed on a predetermined position of the fluid path, an upper inlet and outlet port communicating with the fluid path is formed on the upper plate, a concave groove portion and a fixing end are repeatedly and uniformly formed along a circumference of the upper plate so as to cover the fluid path on the lower plate and be coupled thereto, and the membrane is exposed through the concave groove portion.