Bearing Assembly Spacer Layout for Rotary Shaft Rigidity
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Solution Overview
Problem
Conventional rotary shaft apparatuses face issues with insufficient rigidity, unstable operation, and high costs due to the use of wave springs, adhesive layers, or interference-fits for fastening the outer ring within the bearing housing, which can lead to reduced reliability and precision.
Innovation Solution
A bearing assembly comprising a first and second bearing housing, a spacer, and rolling elements, where the spacer is positioned between the bearings to enhance rigidity and stability without using wave springs, adhesive layers, or interference-fits, allowing for easy assembly and operation across varying temperatures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a wave spring is used to fasten the outer ring within the bearing housing, then the structure is simple and cost is low, but the rigidity of the bearing unit is insufficient
Solution Approach 1:
The patent removes the wave spring component entirely from the bearing assembly. Instead of using a wave spring to fasten the outer ring, the invention relies on the interference fit between the outer ring and bearing housing, combined with precise dimensional control of the bearing unit, to achieve both simplicity and rigidity without requiring additional fastening elements.
Solution Approach 2:
The patent introduces a dust cover as an intermediary component that serves multiple functions: it seals the bearing unit, provides a mounting surface for the bearing assembly, and works in conjunction with the O-ring to create an effective seal. This intermediary structure enables the bearing unit to be securely mounted without requiring wave springs or complex fastening mechanisms.
2Strength
If an adhesive layer is used to fasten the outer ring within the bearing housing, then the rigidity is enhanced, but the operation stability becomes unstable when roundness is not satisfied
Solution Approach 1:
The patent replaces the adhesive bonding mechanism with a purely mechanical interference fit system. The outer ring is designed with dimensional tolerances that create an interference fit with the bearing housing, providing rigid mounting without requiring adhesives. This mechanical solution eliminates the sensitivity to roundness errors that plagues adhesive-based systems.
Solution Approach 2:
The patent employs precise control of dimensional parameters, particularly the inner diameter of the outer ring and the outer diameter of the bearing housing, to create an interference fit. By carefully selecting and controlling these dimensional parameters within specific tolerance ranges, the invention achieves both rigidity and operational stability without relying on adhesives.
3Strength
If an interference-fit manner is used to fasten the outer ring within the bearing housing, then the rigidity and precision are enhanced, but high processing accuracy is required and cost is increased
Solution Approach 1:
The patent applies a moderate interference fit rather than an excessive one. The dimensional tolerances are designed to provide sufficient interference for rigidity while remaining within achievable manufacturing capabilities. This partial interference approach achieves the necessary rigidity without demanding ultra-precise processing that would dramatically increase costs.
Solution Approach 2:
The patent optimizes the interference fit parameters by carefully selecting the tolerance ranges for the outer ring inner diameter and bearing housing outer diameter. The interference amount is controlled to be within a specific range that provides adequate rigidity while remaining manufacturable with standard precision machining capabilities, avoiding both excessive looseness and overly tight fits.
4Volume of moving object
If the bearing unit is thinned to reduce size, then the compactness is improved, but the wave spring position becomes hard to control and may contact the dust cover
Solution Approach 1:
The patent removes the wave spring component that causes positioning problems in thinned bearing units. By eliminating this component entirely and relying on the interference fit between the outer ring and bearing housing, the invention achieves compactness without the positioning and contact issues that arise when wave springs are used in thin configurations.
Solution Approach 2:
The dust cover is designed as an integrated intermediary component that provides both sealing and mounting functions. It works in conjunction with the O-ring to seal the bearing unit while its structure on the bearing housing provides the mounting surface for the bearing assembly, eliminating the need for wave springs and their associated positioning problems.
Data Source
AI summary
A bearing assembly and a rotary shaft apparatus employing the same are provided. The bearing assembly is rotatably coupled with a first shaft and a second shaft. The first bearing housing includes a first annular recess having a first axial depth. The first bearing is connected with the first annular recess and the first shaft and has a first axial thickness. The second bearing housing includes a second annular recess having a second axial depth. The second bearing is connected with the first annular recess, the second annular recess and the second shaft and has a second axial thickness. The spacer is disposed between the first bearing and the second bearing and has a third axial thickness. The sum of the first axial thickness, the second axial thickness and the third axial thickness is greater than the sum of the first axial depth and the second axial depth.