Bearing Inner Ring Trunnion Assembly Arrangement
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Solution Overview
Problem
Existing assembly arrangements between an inner bearing ring and a journal in turbomachines face issues such as unsatisfactory service life due to material differences causing welding difficulties and increased axial length requirements for clamping mechanisms, which are not ideal for compact turbomachine designs.
Innovation Solution
A mechanical assembly arrangement featuring an annular journal groove on the journal and an annular ring groove on the inner ring, with a snap ring and recesses/tooth combinations to prevent axial translation and rotational displacement, respectively, allowing for a compact design without increasing the journal's axial length.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of moving object
If welding is used to attach the inner bearing ring to the journal, then the assembly is compact, but the service life is unsatisfactory due to material differences causing welding difficulties
Solution Approach 1:
The assembly is segmented into distinct components: the journal, the inner bearing ring, and a separate snap ring. This segmentation allows each component to be optimized independently - the journal and inner ring can be made from different materials without welding, while the snap ring provides a reliable mechanical connection that accommodates material differences and thermal expansion variations.
Solution Approach 2:
The snap ring acts as an intermediary element between the journal and the inner bearing ring. It mediates the connection by providing a mechanical interlock through the annular groove and engagement features, eliminating the need for direct welding between dissimilar materials while maintaining structural integrity and service life.
2Reliability
If a clamping nut and anti-rotation device are used to fix the inner bearing ring, then welding drawbacks are avoided, but the axial length of the journal must be increased
Solution Approach 1:
Instead of using axial clamping features that extend the journal length, the solution moves the retention mechanism to the radial dimension. The snap ring engages with the journal through radial features (annular groove and engagement protrusions) while constraining axial movement, thereby maintaining a compact axial profile while achieving reliable fixation.
Solution Approach 2:
Rather than extending the journal axially to accommodate clamping nuts and anti-rotation devices, the solution inverts the approach by using a snap ring that fits into an annular groove on the journal's outer surface. This inverts the retention mechanism from an axial extension to a radial engagement feature, preserving compact dimensions.
3Length of moving object
If welding is used to attach the inner bearing ring to the journal, then the assembly is compact, but manufacturing difficulty increases due to material differences
Solution Approach 1:
The connection is segmented into separate mechanical features: the annular groove in the journal, the snap ring, and the engagement protrusions on the inner bearing ring. This segmentation eliminates the need for welding operations between dissimilar materials, allowing each component to be manufactured independently using standard machining processes and then assembled mechanically.
Solution Approach 2:
The snap ring serves as a intermediary component that simplifies manufacturing by eliminating direct welding between the journal and inner bearing ring. It provides a standardized mechanical connection that can be manufactured and assembled using conventional processes, improving ease of manufacture while maintaining compact dimensions.
Data Source
Figure 1~2
Figure 3
AI summary
The assembly arrangement between an inner ring (6) of a bearing and a trunnion (2) supported in rotation in this bearing comprises: - an annular groove of the trunnion (36) and an annular groove of the ring (26) which cooperate to form an annular channel (52) when they are arranged opposite each other, - a ring (40) disposed in said annular channel (52), which prevents a relative displacement, in translation between said trunnion (2) and said inner ring (6), and - at least one recess (38) of said trunnion (2) and at least one tooth (32) of said inner ring (6), which cooperate to prevent a relative displacement, in rotation between said trunnion (2) and said inner ring (6).