Shock Absorber Mesh and Spiral Spring for Low-Noise Damping
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Solution Overview
Problem
Existing shock absorbers for internal-combustion engine exhaust manifolds fail to effectively reduce contact noise while maintaining high vibration damping performance, particularly in quieter vehicles like hybrids and electric vehicles.
Innovation Solution
A shock absorber design featuring a tubular collar with annular flanges, an annular compression mesh with a radially inner peripheral portion loosely fitted on the collar shaft, and a spiral spring with a lower spring constant than the mesh, combined with a movement restrictor that contacts the spring to restrict radial movement, providing frictional damping and enhanced vibration absorption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the shock absorbing member is loosely fitted on the collar with a clearance to improve vibration damping performance, then vibration damping performance is improved, but contact noise is generated as the shock absorbing member hits the collar
Solution Approach 1:
The patent introduces a spring as an intermediary element between the shock absorbing member and the collar. This spring mediates the interaction by providing continuous contact and elastic cushioning, preventing direct impact between the shock absorbing member and collar while maintaining the clearance needed for vibration damping. The spring acts as a buffer that eliminates impact noise while preserving vibration absorption functionality.
2Object-generated harmful factors
If the spring constant of the spring is made equal to or smaller than that of the shock absorbing member to reduce contact noise, then contact noise is reduced, but vibration damping performance cannot be improved further
Solution Approach 1:
The patent optimizes the spring constant parameter of the spring to be equal to or smaller than that of the shock absorbing member. This parameter adjustment allows the spring to be sufficiently compliant to prevent impact noise while still providing adequate support for vibration damping. The specific parameter relationship creates a balanced system where both noise reduction and vibration damping requirements are satisfied simultaneously.
3Stability of the object's composition
If the radially inner peripheral portion of the shock absorbing member is made thicker to improve structural stability, then structural stability is improved, but the movement restrictor cannot effectively restrict radial movement of the spring
Solution Approach 1:
The patent applies local quality by making the radially inner peripheral portion of the shock absorbing member thicker than the radially outer peripheral portion. This localized thickness increase provides structural stability where needed (at the inner portion near the collar) while maintaining a thinner outer portion that allows the movement restrictor to effectively limit spring movement. The non-uniform thickness distribution optimizes both structural integrity and movement control functionality.
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 solution effectively reduces contact noise and enhances vibration damping performance by allowing radial movement of the compression mesh relative to the collar while maintaining stable posture and preventing wire contact, resulting in improved damping and reduced noise in quieter vehicles.
Implementation Method 1
a spring located between at least one of the flanges on the collar and the shock absorbing member, and overlaid on the shock absorbing member
Implementation Method 2
the spring has a spring constant equal to or smaller than a spring constant of the shock absorbing member
Implementation Method 3
The shock absorbing member includes a movement restrictor in contact with the spring to restrict radial movement of the spring relative to the shock absorbing member
Data Source
AI summary
A shock absorber and a metal cover reduce contact noise generated as a shock absorbing member hits a collar and have higher vibration damping performance. A shock absorber absorbing vibration to a heat insulator covering an exhaust manifold as a vibration source includes a collar, a grommet, an annular compression mesh including a shock absorbing material, and a spiral spring overlaid on a compression mesh. The compression mesh has a center hole loosely receiving a collar shaft. The spiral spring spiral in a plan view has a spring constant equal to or smaller than that of the compression mesh. The compression mesh includes a restriction ridge along a lower large-diameter portion to restrict radial movement of the spiral spring relative to the compression mesh. The circumferential contact area X of the lower large-diameter portion with the restriction ridge ranges between 40% and 55%.