Segmented Bearing Cage with Axial Recesses for Injection Molding
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Solution Overview
Problem
Large-diameter bearings with segmented cages face challenges in uniform material injection and cooling shrinkage during manufacturing, leading to mechanical property degradation, deformation, and breakage due to non-uniform geometries and trapped air bubbles in synthetic material molding processes.
Innovation Solution
The design incorporates a cage segment with varying thickness radial beams, axial recesses, and circumferential beams to improve injection molding feasibility and reduce material volume, featuring recesses that enhance material flow and reduce cooling time, while maintaining mechanical integrity through optimized geometry and material distribution.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Weight of moving object
If segments are made from synthetic material using injection molding, then weight is reduced and ease of manufacture is improved, but manufacturing precision deteriorates due to non-uniform cooling shrinkage and trapped air bubbles
Solution Approach 1:
The patent applies local quality by varying the thickness of different portions of the cage segment. Specifically, the radial beams have different thicknesses at different locations, and the end portions have varying thicknesses. This non-uniform thickness distribution compensates for the non-uniform cooling shrinkage that occurs during injection molding, allowing the segment to maintain dimensional accuracy and geometric uniformity despite the inherent shrinkage variations. The thinner portions shrink less while thicker portions shrink more, balancing out the overall dimensional stability.
2Adaptability or versatility
If segments have large dimensions and complex geometry with varying thicknesses, then functionality is improved, but injection molding becomes difficult and productivity decreases
Solution Approach 1:
The patent applies preliminary action by incorporating axial recesses in the radial beams and end portions before the injection molding process. These pre-designed recesses serve as pathways that guide the flow of molten synthetic material during injection, ensuring uniform filling of the mold cavity. By preparing these flow channels in advance, the complex geometry with varying thicknesses can be successfully manufactured without trapping air bubbles, thereby maintaining both functionality and manufacturing efficiency.
3Strength
If metallic segments are used, then strength and reliability are improved, but weight increases and ease of manufacture decreases
Solution Approach 1:
The patent applies parameter changes by optimizing the thickness parameters of the synthetic material segments. Instead of using uniform thickness, the design incorporates varying thicknesses in different portions - thinner where strength is less critical and thicker where structural support is needed. This parameter optimization allows synthetic material to achieve the required mechanical strength while maintaining weight advantages over metallic segments. The optimized geometry compensates for the inherently lower strength of synthetic material through strategic thickness distribution.
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 approach reduces cooling time, minimizes deformation, and increases manufacturing reliability, resulting in a lighter, more rigid, and cost-effective segmented cage with improved mechanical properties and reduced material usage.
Implementation Method 1
the shrinkage occurring during the cooling of the injected material
Implementation Method 2
the shrinkage occurring during the cooling of the injected material is not uniform and lead to deformation of the segment
Data Source
AI summary
A cage segment for a bearing rotatable around an axis being able to receive a plurality of rolling elements configured to travel on two annular raceways respectively on inner and outer rings of the bearing, and including an inner wall that extends circumferentially in the form of a cylinder, the axis of symmetry being the axis (X1), an outer wall that extends circumferentially in the form of a cylinder, the axis of symmetry being the axis (X1), two end portions that are circumferentially opposed, which extend radially with respect to the axis (X1) and which connect together the inner wall and the outer wall, a plurality of successive pockets for receiving the rolling elements, so that two successive pockets are circumferentially delimitated by a radial beam, The radial beam extending radially with respect to the axis (X1), the radial beam comprising two end portions so that one end portion connects with the inner wall and the other end portion connects with the outer wall, The radial beam provides a first recess that extends axially with respect to the axis (X1).