Track Hinge Joint Sealing With Rotatable Outer Bushing
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Solution Overview
Problem
Track chain assemblies in earth-moving and construction equipment experience wear and lubricant leakage due to high tension and loads, leading to frequent maintenance needs, as existing sealing systems fail to effectively seal lubricant within the track chain assembly.
Innovation Solution
A track hinge joint design featuring a rotatable outer bushing with a fluid seal assembly that contacts the outer bushing end face and track link, preventing lubricant leakage while allowing the outer bushing to rotate, thereby reducing wear on components.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a rotatable sleeve with dust seal is used, then the track structure is simplified, but lubrication is limited leading to increased wear
Solution Approach 1:
The patent implements a nested bushing structure where an inner bushing is placed inside an outer bushing. The inner bushing fits within the rotatable sleeve while the outer bushing encompasses it, creating a multi-layered protective system that provides enhanced lubrication zones without complicating the overall track structure
Solution Approach 2:
The bushing system is divided into separate functional components: an inner bushing for primary lubrication and an outer bushing for secondary lubrication and protection. This segmentation allows each component to perform its specific function optimally, with the inner bushing handling direct contact lubrication and the outer bushing providing additional lubrication reservoir and protection
2Reliability
If seals are placed to retain lubricant, then wear is reduced, but the seals become damaged and lubricant leaks
Solution Approach 1:
The outer bushing acts as a protective cushion for the sealing system. It provides a secondary containment zone that absorbs external contaminants and mechanical stresses before they reach the primary seal, thereby preventing seal damage and lubricant leakage while maintaining wear resistance
Solution Approach 2:
The outer bushing serves as an intermediary protective layer between the external environment and the inner bushing seal system. It mediates the interaction by filtering contaminants and distributing loads, thereby protecting the primary sealing system from damage while maintaining effective lubricant retention
3Reliability
If the inner bushing diameter is increased, then lubrication space is improved, but the ratio to track pin diameter becomes excessive
Solution Approach 1:
By nesting the inner bushing within the outer bushing, the system creates multiple lubrication zones without requiring a single oversized bushing. The inner bushing can be optimized for lubrication space while the outer bushing provides additional containment, allowing the inner bushing diameter to be increased for better lubrication without creating excessive overall dimensions
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 significantly reduces the need for maintenance by preventing lubricant leakage and minimizing wear on track chain components, enhancing the longevity and reliability of the track chain assembly.
Implementation Method 1
friction created between the drive sprocket and the bushing may create wear
Data Source
AI summary
A track hinge joint includes a first track link, a second track link, a track pin disposed in a bore of the first track link, an inner bushing that is disposed in a bore of the second track link and that is rotatable relative to the track pin, an outer bushing that is disposed about the inner bushing that is rotatable relative to the inner bushing and that includes an outer bushing end face, and a first fluid seal assembly contacting the outer bushing end face and the second track link.