Segmented Bearing Seal Structure for Final Gap Control
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Solution Overview
Problem
Rolling bearings in oil-lubricated systems face issues with foreign objects like wear dust entering the operation mechanism, leading to reduced durability and malfunction, and existing solutions have dimension errors and complex sensor structures.
Innovation Solution
A rolling bearing unit with a circular annular seal member divided into circumferentially adjacent parts, coupled by coupling pieces, and equipped with distance adjusting means to manage the final gap between the seal member and the inner race, along with a sensor device to detect foreign objects, ensuring effective filtration and detection without complex structures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a seal member is fixed to the outer race of the rolling bearing, then foreign objects can be prevented from flowing from the interior of the rolling bearing to the operation mechanism, but the radially inner edge of the seal member may come into sliding contact with the radially outer surface of the inner race due to dimension errors and thermal expansion, causing wear and final gap expansion
Solution Approach 1:
The seal member is divided into multiple segments (first seal member and second seal member) that can independently adjust their positions. This segmentation allows each segment to accommodate dimensional variations and thermal expansion without forcing contact with the inner race, thereby preventing wear while maintaining the barrier function against foreign objects.
Solution Approach 2:
The seal member structure incorporates adjustability, transforming it from a static component to a dynamic one. The position of the radially inner edge can be adjusted to maintain the final gap under varying conditions (dimension errors, thermal expansion), preventing harmful contact with the inner race while preserving the foreign object barrier.
2Manufacturing precision
If the final gap between the seal member and the inner race is made small to prevent foreign objects from entering, then filtration effectiveness is improved, but any dimension error or thermal expansion causes the seal member to contact the inner race, leading to wear and gap expansion
Solution Approach 1:
Dividing the seal member into adjustable segments enables precise control of the final gap dimension while accommodating manufacturing tolerances. Each segment can be positioned to maintain the optimal gap size without forcing contact, thus preserving both filtration effectiveness and wear resistance.
Solution Approach 2:
The structure allows for adjustment of the final gap parameter under different operating conditions. By making the seal member position adjustable, the system can adapt to thermal expansion and manufacturing variations, maintaining the optimal gap dimension for filtration while preventing wear through contact avoidance.
3Reliability
If a circular annular seal member with filters is mounted to prevent foreign objects from flowing, then the durability of the operation mechanism is improved, but the structure becomes more complex and requires precise management of the final gap
Solution Approach 1:
The seal member is segmented into multiple independent parts that can be assembled and adjusted more easily than a single complex ring. This segmentation simplifies the management of the final gap by allowing individual adjustment of each segment, reducing the overall complexity of installation and maintenance while maintaining durability.
Solution Approach 2:
The adjustable nature of the segmented seal member simplifies gap management compared to a fixed complex structure. The ability to adjust the position of each segment provides a straightforward method to control the final gap, reducing the complexity of precision management requirements while ensuring durable operation mechanism protection.
Data Source
AI summary
A rolling bearing unit includes an outer race and an inner race between which a bearing space is defined; and a circular annular seal member covering a side opening of the bearing space. The circular annular seal member is constituted by a plurality of circumferentially divided seal member parts circumferentially adjacent to each other, and coupled together as a circular annular coupled member by coupling pieces. The seal member includes a distance adjuster capable of adjusting the circumferential distance between a pair of connection portions where the seal member parts are connected to one of the coupling pieces.