Snap-Connected Bearing Cage Structure Against Umbrella Effect
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Solution Overview
Problem
Conventional rolling-element bearing cages experience the 'umbrella effect' at high rotational speeds, where cantilevered crosspieces bend radially outward, leading to changed pocket geometry and potential rubbing with the outer ring of the bearing.
Innovation Solution
A rolling-element bearing cage design featuring a first cage ring with an axial extension and snap arms directly attached to the extension, which snap into an attachment portion on a second cage ring, minimizing deflection and maintaining compactness even at high rotational speeds.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If conventional one-part cage design with cantilevered crosspieces is used, then the cage structure is simple, but at high rotational speeds the crosspieces bend radially outward causing umbrella effect and limiting bearing rotational speed
Solution Approach 1:
The cage is divided into two separate cage rings instead of being a single one-part structure. The first cage ring includes an axial extension with snap arms that connect to the second cage ring, creating a segmented structure that reduces centrifugal force on individual components and prevents the umbrella effect at high speeds.
2Speed
If two cage halves manufactured from brass or fabric-reinforced phenolic resin are riveted together, then the cage can withstand higher speeds, but the manufacturing complexity and assembly difficulty increase
Solution Approach 1:
The snap arms are integrally formed with the first cage ring's axial extension, eliminating the need for separate riveting operations. The snap connection is formed as a single integrated component during molding, combining the advantages of two-cage design with simplified manufacturing and assembly.
Solution Approach 2:
The cage rings are manufactured from fiber-reinforced plastic material that combines high strength, rigidity, and resistance to centrifugal forces, enabling the cage to operate at high speeds while maintaining structural integrity without requiring traditional riveted construction.
3Reliability
If snap arms are disposed on radially upper and lower sides, then the snap connection is formed, but the radial distance from the central axis increases causing greater deflection at high speeds
Solution Approach 1:
The snap arms are repositioned from radial orientation to axial orientation on the extension. This dimensional change places the snap connection in the axial direction rather than radial direction, minimizing the moment arm and reducing deflection under centrifugal force at high speeds while maintaining reliable snap connection.
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 design allows for high rotational speeds without the umbrella effect, achieving a compact and stable rolling-element bearing cage suitable for both high-speed applications and smaller bearings.
Implementation Method 1
at least one snap arm (20) which is formed directly on the extension (14) and has a smaller distance from the central axis (28) than the attachment region (24)
Implementation Method 2
the cantilevered crosspieces are subjected to a centrifugal force due to the rotational speed. At high rotational speeds, the crosspieces bend radially outward
Data Source
AI summary
A rolling-element bearing cage having a central axis of rotation includes a first cage ring having an axial extension and at least one snap arm disposed directly on the extension, and a second cage ring having an attachment region to which the at least one snap arm is snapped. The attachment region is located at a first distance from the central axis of rotation. A portion of each of the at least one each snap arm of the first cage ring is located at a second distance from the central axis of rotation, the second distance being less than the first distance.