Two-Piece Roller Retainer Cage for Wear-Resistant Bearing Assembly

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Solution Overview

Problem

Roller thrust bearings face issues with drilling wear, particularly under high-speed and high-temperature conditions due to inadequate lubrication, and through-hardened materials can crack during assembly in roller retainer cages.

Innovation Solution

A two-piece roller retainer cage design with a through-hardened first cage half and a carburized second cage half, where the first cage half has consistent hardness across its thickness to prevent drilling wear and the second cage half is designed to withstand crimping without cracking, using surface treatments like solid lubricants and hard coatings to reduce friction.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If through-hardened materials are used for the roller retainer cage, then drilling wear resistance is improved, but cracking occurs during assembly crimping

Engineering Contradiction:

Improvedrilling wear resistanceVSAvoidcrack resistance during assembly

Core Design Contradiction:

ReliabilityVSStrength

Solution Approach 1:

The cage half is designed with non-uniform hardness distribution: the flange portions are through-hardened to resist drilling wear from roller end faces, while the web portions maintain lower hardness to allow plastic deformation during crimping without cracking. This local differentiation of material properties resolves the contradiction between wear resistance and assembly ductility.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The heat treatment parameters are specifically controlled to achieve different hardness levels in different regions of the cage half. The flange regions are hardened to high hardness values (e.g., HRC 50-65) for wear resistance, while the web regions are maintained at lower hardness values to provide sufficient elongation capacity during the crimping process.

Inventive Principle:

Principle #35Parameter changes

2Strength

If case carburized material is used for the roller retainer cage, then a hard protective layer is formed, but the soft core cannot withstand drilling wear under high speed conditions

Engineering Contradiction:

Improveprotective layer hardnessVSAvoiddrilling wear resistance under high speed

Core Design Contradiction:

StrengthVSReliability

Solution Approach 1:

Instead of using case carburized material with a soft core, the invention applies through-hardening specifically to the flange portions where drilling wear occurs. This creates a uniformly hard surface layer throughout the flange thickness, eliminating the soft core vulnerability while maintaining the benefits of heat treatment in the web portions.

Inventive Principle:

Principle #3Local quality

3Reliability

If high hardness material is used for the roller retainer cage, then drilling wear is prevented, but the cage cannot be crimped during assembly

Engineering Contradiction:

Improvedrilling wear preventionVSAvoidcrimping capability

Core Design Contradiction:

ReliabilityVSEase of manufacture

Solution Approach 1:

Inventive Principle:

Principle #3Local quality

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

The solution effectively prevents accelerated drilling wear and allows for assembly without cracking, enhancing the durability and reliability of roller thrust bearings under demanding conditions.

Implementation Method 1

the first cage half is comprised of a through-hardened metal

Methodology Applied

Scientific EffectThrough-hardening: Heat Treatment

Implementation Method 2

A material often used in manufacturing this type of roller retainer cage is SAE 1010 steel, especially in high speed applications such as air conditioning (AC) compressors. Referring additionally to FIG. 3A, a preferred heat treatment for the cage halves in such applications is case carburizing, which results in a case depth layer 10 (hard zone) protecting a soft core 12 (soft zone) of the corresponding cage half 14.

Methodology Applied

Scientific EffectCase carburizing: Carburizing

Implementation Method 3

using surface treatments like solid lubricants and hard coatings to reduce friction

Methodology Applied

Scientific EffectSolid lubrication: Lubrication

Data Source

PatentUS11353060B2Two-piece roller retainer cage for a roller thrust bearing

Publication Date: 2022.06.07 JTEKT BEARINGS NORTH AMERICA LLC

AI summary

A roller retainer cage for a roller thrust bearing, including a first cage half with an annular portion, a first flange extending axially from an inner peripheral edge of the annular portion and a second flange extending axially from an outer peripheral edge of the annular portion, a second cage half including an annular portion, a first flange extending axially from an inner peripheral edge of the annular portion and a second flange extending axially from an outer peripheral edge of the annular portion, wherein the first flange of the first cage half is disposed radially-outwardly of the first flange of the second cage half, the second flange of the first cage half is disposed radially-inwardly of the second flange of the second cage half, and the first cage half is comprised of a through-hardened metal.