Resin Cage Conical Surfaces for Tapered Roller Bearing Assembly

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Solution Overview

Problem

Existing resin cages for tapered roller bearings face challenges in assembly efficiency and manufacturing cost due to complex and expensive mold requirements, with issues of roller drop-out and insufficient holding capacity, especially when using axial-draw molding.

Innovation Solution

A resin cage design featuring conical surfaces and radially flat surfaces on adjacent pillar portions, allowing for slide contact with tapered rollers, enabling easy assembly and improved moment rigidity, while maintaining cost-effectiveness through axial-draw molding.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If an axial-draw molding is used to manufacture the resin cage, then manufacturing cost is reduced and mass productivity is improved, but the tapered roller can be dropped out to the inner diameter side and assembly efficiency deteriorates

Engineering Contradiction:
Improvemass productivity of cage manufacturingVSAvoidassembly efficiency of tapered roller bearing
Core Design Contradiction:
ProductivityVSEase of operation

Solution Approach 1:

The cage is divided into multiple pillar portions (first, second, third, fourth pillar portions) with different functional configurations. The first and second pillar portions have conical surfaces for roller holding, while the third and fourth pillar portions have flat surfaces for roller support, allowing the cage to perform multiple functions simultaneously

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Different regions of the cage are given different surface characteristics: conical surfaces on specific pillar portions for active roller holding and flat surfaces on other pillar portions for passive support. This localized functional differentiation enables both cost-effective manufacturing and improved assembly performance

Inventive Principle:
Principle #3Local quality

2Reliability

If a radial draw molding with complex molds is used to prevent roller drop-out, then roller holding reliability is improved, but manufacturing cost increases

Engineering Contradiction:
Improveroller holding reliabilityVSAvoidmanufacturing cost of cage
Core Design Contradiction:
ReliabilityVSEase of manufacture

Solution Approach 1:

Instead of using complex molds for radial draw molding, the invention applies conical surfaces locally on specific pillar portions (first and second pillar portions) that contact the tapered rollers. This localized approach provides reliable roller holding while maintaining the simplicity and cost-effectiveness of axial-draw molding

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The invention changes the surface geometry parameter of specific cage regions from flat to conical, creating a geometric configuration that passively prevents roller drop-out through the shape itself, eliminating the need for complex molding processes

Inventive Principle:
Principle #35Parameter changes

Data Source

PatentEP2982878B1Resin cage for tapered roller bearing and tapered roller bearing including the resin cage
Publication Date: 2018.08.08 NSK LTD
  • EP2982878B1 patent drawingFigure 1A~1B
  • EP2982878B1 patent drawingFigure 2
  • EP2982878B1 patent drawingFigure 3

AI summary

In a tapered roller bearing-use resin made cage (10), a mold parting line (A) extending along the axial direction is formed in pillar sections (13) partitioning pockets (P). In opposing surfaces of adjacent pillar sections (13), on the outer diameter side beyond the mold parting line (A), an inner diameter-side conical surface (15A) is formed in sliding contact with the outer peripheral surface of a tapered roller (4), and formed is a plane (16A) in the radial direction in an outer diameter-side portion beyond the inner diameter-side conical surface (15A). On the inner diameter side beyond the mold parting line (A), an outer diameter-side conical surface (15B) is formed in sliding contact with the outer peripheral surface of the tapered roller (4), and formed is a plane (16B) in the radial direction at an inner diameter-side portion beyond the outer diameter-side conical surface (15B). Due to this configuration, injection molding is made possible while maintaining a shape that enables a cage and roller.