Polyurethane Bushing for Vibration Damping in Exercise Machine Joints
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Solution Overview
Problem
Exercise machines, such as elliptical trainers, experience significant vibrations and noise due to the use of wave washers in joints, which have a limited lifespan of 30,000 rotations and fail to effectively reduce vibrations and noise.
Innovation Solution
The implementation of a bushing with an elastic, flexible polyurethane body sandwiched between circular plates made of a stiffer material, providing a compressive fit between components to absorb vibrations and reduce noise, with a Shore hardness of 30 A to 50 A, significantly increasing the bushing's lifespan to 500,000 rotations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If wave washers are used in joints, then the device can be assembled, but vibrations and noise are not effectively reduced and the lifespan is limited to 30,000 rotations
Solution Approach 1:
The bushing is constructed from composite materials including a polyurethane body combined with metal plates or sleeves, creating a multi-material structure that simultaneously provides vibration damping properties from the polyurethane and structural strength from the metal components, resolving the contradiction between lifespan and vibration reduction
Solution Approach 2:
The invention changes the material parameters by using polyurethane with specific Shore hardness values (30A-50A) and combining it with metal components, transforming the physical properties of the joint to achieve both extended lifespan and effective vibration noise reduction that single-material wave washers cannot provide
2Reliability
If a bushing with elastic polyurethane body and metal plates is used, then vibrations and noise are reduced and lifespan is extended to 500,000 rotations, but the device complexity increases
Solution Approach 1:
The invention merges multiple functional elements into a single integrated bushing component - the polyurethane body, metal plates, and connecting features are combined into one assembly that replaces multiple separate components, reducing assembly complexity while maintaining the composite material benefits for extended lifespan and vibration reduction
Solution Approach 2:
The bushing design incorporates multiple functions within a single component: vibration damping, noise reduction, wear protection, and structural support. The polyurethane body provides elasticity and shock absorption, while metal plates provide structural strength, creating a universal component that addresses multiple issues simultaneously without requiring separate dedicated parts
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 bushing effectively reduces and eliminates vibrations and noise in exercise machine joints, extending the life cycle and improving user experience by maintaining joint alignment and reducing wear and tear.
Implementation Method 1
The bushing includes a body with a first side and a second side, the body comprising an elastic, flexible material
Implementation Method 2
The bushing effectively reduces and eliminates vibrations and noise in exercise machine joints
Implementation Method 3
The bushing is held between the first component and the second component under compression in a direction that is aligned with a length of the pivot rod
Data Source
AI summary
An exercise machine includes a joint assembly. The joint assembly includes a pivot rod, a first component connected to the pivot rod, a second component connected to the pivot rod, and a bushing mounted on the pivot rod between the first component and the second component. The bushing includes a body with a first side and a second side, the body comprising an elastic, flexible material; a first plate connected to the first side of the body; and a second plate connected to the second side of the body.