Integrated Pin Lubrication for Pivot Joint Collision Protection
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Solution Overview
Problem
Existing lubrication systems for pivot joints in heavy machines, such as hydraulic excavators, are prone to damage from collisions during operation, leading to overheating and joint failure due to inadequate lubricant distribution and external grease line vulnerability.
Innovation Solution
A system comprising a pin and coaxially disposed bushings within the cylinder clevis, with grooves and ports for lubricant transmission, and cover plates with press-fit mechanisms and fasteners to ensure even lubricant distribution and protection from collisions, utilizing a spring for enhanced sealing and lubricant flow.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If external grease lines are used for lubrication, then the pivot joint can be lubricated, but the grease lines are vulnerable to collisions and damage during operation
Solution Approach 1:
The grease line is merged with the pin structure itself, forming an integrated lubrication system where the pin contains internal passages and grooves for lubricant flow. This eliminates the external grease line that is vulnerable to collision damage while maintaining the lubrication function.
Solution Approach 2:
The lubrication passages and grooves are nested within the pin structure, with the grease line integrated inside the pin rather than external. This nesting protects the lubrication pathway from external damage while ensuring continuous lubricant delivery to the pivot joint.
2Reliability
If grease is supplied cyclically around the pin perimeter, then the pivot joint can be lubricated, but the grease distribution is not even which may result in joint failure
Solution Approach 1:
The invention employs grooves with varying cross-sectional areas and strategically positioned ports to create non-uniform local characteristics in the lubrication pathway. This ensures that grease is distributed evenly across the pin perimeter by controlling flow rates at different locations, with larger grooves or multiple ports compensating for areas that would otherwise receive insufficient lubrication.
3Ease of repair
If the machine is stopped for repairing damaged grease lines, then the lubrication system can be fixed, but unnecessary downtime occurs
Solution Approach 1:
By merging the grease line with the pin structure to create an integrated lubrication system, the design eliminates the need for separate external grease lines that require repair. The pin itself serves as both the structural component and the lubrication conduit, so no separate repair operation is needed - the pin is replaced as a single integrated unit if damage occurs, significantly reducing downtime.
4Reliability
If external grease lines are used, then lubrication can be provided, but the damage is difficult to spot immediately after it occurs
Solution Approach 1:
The integration of the grease line with the pin structure creates a unified component where damage to the lubrication system is directly associated with visible pin damage or leakage at the pin-bushing interface. This makes damage detection easier compared to external grease lines that can be damaged in ways not immediately apparent, as the integrated design concentrates potential failure points at observable locations.
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 system provides a robust and even lubrication distribution within pivot joints, reducing the risk of damage and downtime by minimizing external lubricant line exposure and ensuring consistent lubrication, even under operational stress.
Implementation Method 1
A spring is placed between the second cover plate and the second side of the pin, enabling a contact between the seal and the first cover plate
Implementation Method 2
The second groove in fluid communication with the first bushing and provided for transmission of a lubricant. The second side having one or more third grooves in fluid communication with the second bushing and provided for transmission of the lubricant
Implementation Method 3
The first side having a first groove provided for mounting a seal
Data Source
AI summary
A system for lubricating a pivot joint including a first bushing and a second bushing and a pin disposed coaxially within a cylinder clevis, the pin having a first groove and a second groove on a first side, and third grooves on a second side and a bore along a length of the pin from first side to the second side. The first groove is used for mounting a seal. The second groove and the third grooves provide transmission of a lubricant to the first bushing and the second bushing respectively. A first cover plate and a second cover plate are fastened to the cylinder clevis using a plurality of fasteners. The first cover plate includes a first port and a second port for providing the lubricant to the first bushing and the second bushing respectively. A spring is provided between the second cover plate and the pin.