Emergency Bearing Mechanism for Cable Sheave Rotation
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Solution Overview
Problem
Bearing damage in a rope sheave of a cable car can lead to operational disruptions, as existing solutions do not allow for continuous rotation of the sheave when the primary bearing is compromised, potentially leaving passengers stranded.
Innovation Solution
A dual-bearing system is implemented, where a main bearing for normal operation is paired with an emergency bearing that can take over in case of damage, ensuring the sheave can continue to rotate until all passengers are safely evacuated and maintenance can be performed, with the emergency bearing being radially positioned outside the main bearing and connected via a shear bolt mechanism to maintain stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a single main bearing is used for normal operation, then the device complexity is reduced and manufacturing cost is lowered, but the reliability decreases because the sheave cannot continue rotating when the bearing is damaged
Solution Approach 1:
The bearing system is segmented into two functionally independent bearings: a main bearing for normal operation and an emergency bearing for backup. The emergency bearing is radially offset from the main bearing, allowing independent installation and operation. This segmentation enables the system to maintain operational continuity by switching to the emergency bearing when the main bearing fails, without requiring a completely redundant complex system.
Solution Approach 2:
The patent changes the spatial parameter by positioning the emergency bearing at a radial offset from the main bearing rather than concentrically. This radial offset arrangement allows the emergency bearing to engage the hub directly when the main bearing fails, creating a functional parameter change that enables continued operation. The bearing type parameter is also changed to use plain bearings for the emergency bearing, which are simpler and more reliable for emergency operation.
2Reliability
If an emergency bearing is added radially outside the main bearing, then the reliability improves by enabling continued rotation after bearing damage, but the device complexity increases due to additional components and installation requirements
Solution Approach 1:
The emergency bearing serves multiple functions: it acts as a structural support element for the hub during normal operation, provides emergency bearing capability when the main bearing fails, and maintains the radial positioning of the hub. This multi-functionality reduces the need for separate emergency components, thereby limiting the increase in device complexity while maintaining improved reliability.
Solution Approach 2:
The emergency bearing is nested within the hub structure, with its inner ring forming part of the hub assembly. This nesting allows the emergency bearing to be integrated into the existing hub design rather than requiring a separate external mounting structure, thereby minimizing the increase in device complexity while enabling the reliability improvement.
3Ease of manufacture
If the inner ring of the emergency bearing is located with play on the hub, then the ease of manufacture improves by simplifying assembly, but the stability worsens because the sheave may tilt during emergency operation
Solution Approach 1:
The play (clearance) is applied locally and selectively only to the emergency bearing's inner ring on the hub, not to the main bearing assembly. This localized play allows for simplified emergency bearing installation and adjustment without affecting the precision and stability of the main bearing operation. The local quality approach ensures that stability is maintained where needed (main bearing) while enabling ease of manufacture where appropriate (emergency bearing assembly).
Data Source
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AI summary
In a bearing unit (3) of a cable sheave (1) of a cableway system, the cable sheave (1) is arranged on a shaft (2) which is mounted in bearings (8, 9) in a bearing framework (4). An inner ring (10) or outer ring (11) of at least a first bearing (8) is connected to the shaft (2). The outer ring (11) or inner ring (10) of said first bearing is connected to an inner ring (13) or outer ring (14) of a second bearing (9) and is mounted in the bearing framework (4) via said second bearing (9).