Internal Ring Sealed Chain Bushing Design
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Solution Overview
Problem
Existing chain systems experience wear and elongation due to debris and abrasive dust in pin-bushing interfaces, leading to reduced chain life, despite lubrication efforts, as existing seals are inadequate in preventing grease leakage and particle ingress.
Innovation Solution
Internal annular grooves in bushings with steel rings and annular rubber seals are used to create a novel sealing mechanism, where steel rings frictionally engage pins and prevent dust and particle ingress, while annular rubber seals on bushing ends prevent contaminants from reaching the pin-bushing interfaces.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of substance
If seals are provided at ends of bushings between inside and outside sidebars, then grease leakage is prevented, but particle ingress and wear continue to occur
Solution Approach 1:
The sealing function is divided into multiple components: steel rings positioned in internal grooves of the bushing, and an outer seal at the end of the bushing. This segmentation allows each seal to address specific aspects of contamination prevention, with steel rings blocking particle ingress at the grease interface and the outer seal preventing contaminant entry at the bushing end.
Solution Approach 2:
The steel rings act as intermediary elements between the grease-lubricated pin-bushing interface and the external environment. These rings are positioned in grooves within the bushing material itself, creating an intermediate barrier that prevents particles from reaching the lubricated interface while maintaining grease containment.
2Duration of action of moving object
If pins have grease fittings and channels to add lubricant, then chain life is extended through lubrication, but seal complexity increases
Solution Approach 1:
The grease delivery function is extracted from the pin and relocated to the bushing structure. Grease fittings and channels are now provided in the bushing rather than the pin, allowing lubricant to be delivered directly to the pin-bushing interface through the bushing material. This simplifies the overall sealing system while maintaining effective lubrication.
3Reliability
If steel rings are frictionally engaged on pins, then sealing effectiveness is improved, but friction and wear at the ring-pin interface increase
Solution Approach 1:
The steel rings are designed to rotate with the pins rather than remaining stationary. This dynamic configuration allows the rings to maintain continuous contact with the pin surface for effective sealing while reducing friction by converting static friction into kinetic friction, which is generally lower and more consistent.
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 sealing mechanism effectively prevents grease leakage and particle ingress, maintaining lubrication within the pin-bushing interfaces and extending chain life by reducing wear and contamination, ensuring longer chain durability.
Implementation Method 1
The steel rings are frictionally engaged on the pins and rotate in the bushing internal grooves
Implementation Method 2
The annular rubber seals have small inner ends that grip the bushing extensions
Data Source
AI summary
Links in industrial chains are connected by pins in bushings. Internal sealing rings in internal annular grooves near ends of bushings prevent inward movement of debris and outward movement of grease past the grooves. Steel internal sealing rings are expanded further into the grooves upon insertion of the pins through the bushings and the steel rings. The steel rings tightly grip the pins and rotate with the pins. Opposite ends of the bushings extend slightly from inside sidebars. Outer conical nitrile seals have collars placed on extended ends of the bushings and have large radiused ends for contacting inner surfaces of outside sidebars that hold the pins.