Tapered Roller Bearing Retainer for Stable Force-Fit Assembly
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Solution Overview
Problem
The existing method of assembling tapered roller bearings, which involves plastic deformation of the steel retainer, leads to residual deformation and contact failure between the tapered roller and the retainer, and is difficult to implement, especially for small-sized bearings, due to the need for caulking and increased working costs.
Innovation Solution
A tapered roller bearing design that eliminates the need for caulking by using a retainer with projecting portions that allow for force-fitting of the rollers, where the projecting portions are separated from the annular portions and have a force-fit margin, enabling elastic deformation and stable assembly without residual deformation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the pillar portions of the retainer are plastically deformed radially outward to enable assembly, then the tapered rollers can be positioned, but residual deformation occurs causing unstable pocket shape and contact failure
Solution Approach 1:
The pillar portion is segmented into a contact portion (with guide surface) and a non-contact portion. The contact portion maintains structural integrity for stable pockets, while the non-contact portion provides elasticity for easy assembly without causing residual deformation that would affect contact stability.
Solution Approach 2:
Different regions of the pillar portion have different properties: the contact portion has a tapered guide surface for precise roller positioning and stability, while the non-contact portion has increased elasticity to facilitate assembly. This local differentiation resolves the contradiction between assembly ease and contact stability.
2Ease of operation
If a slit is formed on the pillar portion to reduce rigidity for elastic deformation, then assembly becomes easier, but the working cost increases and slit formation becomes difficult for small-sized bearings
Solution Approach 1:
Instead of forming a slit throughout the pillar portion, the invention creates a localized non-contact portion with different mechanical properties. This approach provides the necessary elasticity for assembly without requiring complex slit formation processes, especially for small-sized bearings.
Solution Approach 2:
The non-contact portion is designed to dynamically deform elastically during assembly and then recover, providing the necessary flexibility without permanent structural modification like slits. This dynamic behavior achieves assembly ease while maintaining manufacturing simplicity.
3Shape
If the projecting portions are formed close to the annular portions, then the retainer structure is compact, but elastic deformation is restricted reducing force-fit capability
Solution Approach 1:
The projecting portion is segmented into a contact portion (close to annular portions for compactness) and a non-contact portion (extended for elasticity). This segmentation allows the retainer to maintain compact overall shape while providing sufficient elastic deformation capability for force-fit assembly.
Solution Approach 2:
The solution extends the pillar portion in the axial dimension (creating the non-contact portion) to provide elastic deformation capability, while keeping the radial dimension compact. This dimensional approach resolves the contradiction between compactness and force-fit capability.
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
This design allows for smooth assembly of tapered rollers into the retainer pockets through force-fitting, preventing contact failure and reducing the risk of roller removal and damage, while also increasing the roller filling ratio and load capacity of the bearing.
Implementation Method 1
the projecting portions are separated from the annular portions in a roller axis direction and are separated from each other in the roller axis direction. Thus, an area of guide surfaces, which form distal end surfaces of the projecting portions, becomes smaller, and hence the projecting portions and the pillar portions are more likely to be elastically deformed
Data Source
Figure 1
Figure 2
Figure 3A~3D
AI summary
Two projecting portions (45a and 45b) configured to guide a tapered roller (3) on distal end surfaces thereof are formed on a side surface (43a) of a pillar portion (43) of a retainer (4) so as to be separated apart from each other in a roller axis direction. The projecting portions (45a and 45b) are separated apart from each other in the roller axis direction with respect to both a small-diameter-side annular portion (41) and a large-diameter-side annular portion (42). The projecting portions (45a and 45b) each have a force-fit margin (F).