Double-Structure Bush for High-Load Joints
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Solution Overview
Problem
Existing bush technologies for construction machines, particularly in high load and low-speed applications, face challenges with limited elastic strain, wear resistance, and lubrication maintenance due to metal bushes' rigidity and the limited lifespan of self-lubricative coatings, as well as the degradation of porous sintered metal bushes under eccentric loads and shocks.
Innovation Solution
A double-structure bush made of a polymeric composite with a slide layer and a load support layer, where the softening temperatures of the layers are adjusted within specific ranges (120-180°C and 250-400°C respectively) to enhance elasticity, wear resistance, and lubrication characteristics, allowing for uniform load distribution and improved lifespan without periodic greasing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If metal bushes are used to provide rigidity and load support, then load bearing capacity is improved, but elasticity and shock resistance deteriorate
Solution Approach 1:
The bush is constructed as a composite structure with an inner metal layer providing load bearing capacity and an outer polymer layer providing elasticity and shock absorption. This composite structure resolves the contradiction by combining materials with complementary properties - the metal core ensures strength under load while the polymer outer layer provides the necessary elasticity and cushioning against shocks.
2Reliability
If self-lubricative coating is applied to metal bushes, then initial lubrication ability is improved, but lifespan of lubrication deteriorates
Solution Approach 1:
The invention changes the material parameter of the outer layer from metal to polymer, which fundamentally alters the lubrication mechanism. Instead of relying on a depleting self-lubricative coating on metal, the polymer material inherently maintains low friction and lubrication properties throughout its service life, providing sustained lubrication capability without the lifespan limitation of coated metal surfaces.
3Reliability
If porous sintered metal bushes are used to provide lubrication, then initial lubrication effect is improved, but shock resistance and pore integrity deteriorate
Solution Approach 1:
The composite structure replaces the porous sintered metal with a solid polymer outer layer. This polymer layer provides inherent lubrication properties without the structural vulnerability of pores. The solid polymer structure maintains integrity under shock loads while still providing effective lubrication, resolving the contradiction between lubrication effect and shock resistance that plagues porous metal bushes.
4Strength
If metal bushes are used to provide wear resistance, then hardness is improved, but abnormal wear under eccentric load increases
Solution Approach 1:
The composite structure combines the hardness of the inner metal layer for wear resistance with the compliance of the outer polymer layer. The polymer layer acts as a stress-distributing interface that prevents stress concentration under eccentric loads, thereby preventing abnormal wear while maintaining overall wear resistance. The metal core provides hardness against wear while the polymer outer layer protects against abnormal wear patterns caused by eccentric loading.
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 double-structure bush exhibits improved wear resistance, shock resistance, and lubrication characteristics, maintaining performance under varying temperatures and loads, reducing abnormal wear and breakage, and extending lifespan compared to traditional metal bushes.
Implementation Method 1
the inner circumferential surface of the slide layer is in contact with the pin unit to support rotation of the pin unit
Implementation Method 2
the load support layer is in contact with the inner circumferential surface of the boss to support radial load of the pin unit
Implementation Method 3
A double-structure bush made of a polymeric composite that comprises: a slide layer configured to receive a pin unit... and a load support layer integrally stacked on the outer circumferential surface of the slide layer
Data Source
AI summary
The present disclosure relates to a double-structure bush usable in a joint portion which operates in low-speed and high-load, and a bearing assembly comprising the same.