Self-Aligning Seal Assembly for Bearing Misalignment and Contamination
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Solution Overview
Problem
Current sealing systems for bearings, such as those used in conveyor rollers, fail to effectively prevent contamination from dust, abrasive materials, and water due to the permeability of grease used in labyrinth seals, which can become contaminated and compromise the bearing's lubricant, leading to potential failure.
Innovation Solution
A self-aligning seal assembly utilizing pressurized oil within a cavity between seals, where the inner seal carrier can angularly adjust to maintain alignment with the shaft, and the outer carrier allows for lateral movement, using oversized holes and flexible seals to ensure a secure fit on the bearing housing while maintaining a positive seal against contamination.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If grease is used as the sealing medium in labyrinth seals, then the seal assembly can be simple in structure and easy to manufacture, but the grease becomes contaminated by dust and abrasive material, compromising the bearing lubricant
Solution Approach 1:
The patent extracts the sealing function from the lubricating function by using separate media: oil for sealing and grease for lubrication. The oil-based seal assembly removes the contaminating grease from the sealing pathway, allowing the bearing to be protected from dust and abrasive material while maintaining simple structure
Solution Approach 2:
The patent introduces oil as an intermediary sealing medium between the external environment and the bearing. This oil-based intermediary prevents direct contact between contaminants and the bearing lubricant, solving the contamination problem while maintaining manufacturing simplicity
2Adaptability or versatility
If the labyrinth grooves have significant clearance to accommodate misalignment, then the seal assembly can accommodate misalignment, but the grease must fill the clearance which reduces sealing effectiveness
Solution Approach 1:
The patent makes the seal assembly dynamic by allowing the inner seal carrier to rotate independently within the outer carrier. This dynamic adjustment enables the seals to maintain contact with the shaft despite misalignment, while the oil-based sealing medium fills the clearances more effectively than grease, maintaining sealing reliability
Solution Approach 2:
The patent changes the physical parameter of the sealing medium from grease to oil, which has different flow and filling characteristics. Oil fills the clearance gaps more effectively and maintains sealing pressure better, allowing the seal to accommodate misalignment while maintaining reliability
3Ease of operation
If conventional seals require oil to lubricate the seal lip face, then the seal can function properly, but shaft damage may result if oil is not adequately supplied
Solution Approach 1:
The patent implements a self-service lubrication system where the oil supply to the seal lip face is automatically maintained through the rotation of the shaft and the design of the oil reservoir. The system self-regulates oil distribution without external intervention, ensuring continuous lubrication and preventing shaft damage while maintaining ease of operation
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 pressurized oil seal assembly effectively prevents contamination by maintaining a consistent seal despite misalignment and ensuring the seals remain in contact with the shaft, reducing the risk of bearing failure by using a flexible and adjustable design that accommodates radial, vertical, and horizontal misalignments.
Implementation Method 1
the seal assembly including oil within a cavity between the seals... the oil is within the cavity at a pressure at or above atmospheric pressure at the location of the seal assembly
Implementation Method 2
the inner seal carrier having an outer curved surface allowing angular positional adjustment of the inner seal carrier within the outer carrier
Data Source
AI summary
A seal assembly (10, 110) has an inner seal carrier (14, 114) with seals (16, 116, 18, 118), an outer carrier (30, 130) with inner curved surface (144) matching an outer curved surface (146) of the inner seal carrier for angular pitch adjustment of 3° to 5° for the inner seal carrier within the outer carrier, a flexible seal (36, 136) between the outer carrier and the bearing housing (28, 128), and oil within a cavity (20, 120) between the seals, preferably above atmospheric pressure. Shoulder bolts (140) allow lateral movement of the seal assembly with respect to the bearing housing. The seal assembly allows for misalignment and lack of parallelism of the shaft relative to the bearing housing whilst preventing contamination of the bearing.