Tubular Vibration-Damping Device Locking Projection
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Tubular vibration-damping devices with synthetic resin outer tube members face challenges in maintaining stable press fitting and sufficient pull-out resistance due to permanent set-in fatigue and deformation, especially when subjected to axial loads, making it difficult to ensure long-term stability and resistance against falling out of the mounting hole.
Innovation Solution
The device incorporates a synthetic resin outer tube member with a locking projection and a stopper support part that utilizes the bulging deformation of a stopper rubber to restrict deformation of the locking part, ensuring effective locking and pull-out resistance by positioning the locking part outside the stopper support part across a recess, allowing for easy insertion and maintaining a stable locked state under axial loads.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a locking projection is provided on the outer tube member to increase pull-out resistance force, then pull-out resistance force is improved, but the locking projection becomes an obstacle during insertion and device complexity increases
Solution Approach 1:
The locking part is divided into two functional segments: a locking projection for engagement with the mounting hole, and a stopper support part for supporting the stopper rubber. This segmentation allows each part to perform its specific function optimally while reducing overall structural complexity.
Solution Approach 2:
The stopper rubber acts as an intermediary element between the locking part and the outer tube member. It transmits axial loads to the locking part, enabling the locking projection to engage effectively with the mounting hole while the stopper rubber absorbs deformation and prevents direct stress concentration.
2Strength
If the projection height of the locking projection is enlarged to increase pull-out resistance force, then pull-out resistance force is improved, but insertion becomes more difficult and device complexity increases
Solution Approach 1:
The stopper rubber undergoes parameter changes during operation: in the inserted state, it maintains a relaxed configuration allowing easy insertion; when axial load is applied, it deforms and swells to engage the locking projection, transforming from a non-intrusive state to an active locking state.
Solution Approach 2:
The locking mechanism transitions from a static structure to a dynamic system where the stopper rubber deforms under axial load to activate the locking projection. This dynamic behavior allows the locking part to engage securely only when needed, maintaining ease of insertion during installation.
3Weight of moving object
If the outer tube member is made of synthetic resin to reduce weight and manufacturing cost, then weight and manufacturing cost are reduced, but press fitting stability and pull-out resistance deteriorate due to permanent set-in fatigue
Solution Approach 1:
The device uses a composite structure combining synthetic resin outer tube member with rubber elastic components (stopper rubber and main rubber elastic body). This composite material approach leverages the lightweight and cost-effective properties of synthetic resin while using rubber materials to provide the necessary elasticity, damping, and load-bearing capabilities that pure plastic materials lack.
Solution Approach 2:
The stopper rubber undergoes parameter changes during operation: in the inserted state, it maintains a relaxed configuration allowing easy insertion; when axial load is applied, it deforms and swells to engage the locking projection, transforming from a non-intrusive state to an active locking state.
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
This configuration effectively prevents the outer tube member from falling out of the mounting hole, providing sufficient pull-out resistance and maintaining a stable locked state even under large axial loads, while allowing for easy insertion and reducing manufacturing complexity.
Implementation Method 1
deformation of the locking part to an inner circumference side is restricted by the stopper rubber swelling to the outer circumference side along with its compressive deformation in an axial direction
Implementation Method 2
a main rubber elastic body coupling the inner shaft member and the outer tube member
Data Source
AI summary
A tubular vibration-damping device including: an inner shaft member; an outer tube member; and a main rubber elastic body which couples the two members. The outer tube member is made of synthetic resin and integrally includes on its first axial end a locking part having a locking projection on its outer circumference surface and a stopper support part that supports a base end part of a stopper rubber projecting axially outward therefrom. The locking part is positioned at an outer circumference side of the stopper support part across a recess that opens axially outward of the outer tube member. Deformation of the locking part to an inner circumference side is restricted by the stopper rubber swelling to the outer circumference side along with its compressive deformation in an axial direction and abutting against an inner circumference surface of the locking part.