Thrust Bearing Hook Curl Radial Guidance Retainer

Resolve Bottlenecks,
Find Innovative Solutions
Generate Solutions

Solution Overview

Problem

Thrust bearings used in automotive transmissions experience increased surface pressure and wear when subjected to radial loads or displacements due to reduced retainer thickness, making them prone to premature failure and difficult to manufacture thinly while maintaining mounting ability.

Innovation Solution

The design incorporates a hook curl part formed by bending the race part acutely in the radial direction, with a conical surface on the retainer that contacts the hook curl part in a sliding manner, providing both holding and guiding functions, and ensuring a larger contact area to reduce surface pressure and wear, even when the bearing is made thin.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Length of moving object

If the retainer thickness is reduced to make the thrust bearing thin, then the thrust bearing can be made thinner, but the area of the outer peripheral surface of the retainer is reduced, causing increased surface pressure and wear

Engineering Contradiction:
Improvethrust bearing thicknessVSAvoidwear resistance
Core Design Contradiction:
Length of moving objectVSReliability

Solution Approach 1:

The invention transitions from axial guidance (in the thickness direction) to radial guidance (in the radial direction) by adding the hook curl part. This allows the retainer to be guided radially by the hook curl part while maintaining a thin axial profile, thus resolving the contradiction between thinness and wear resistance.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

Solution Approach 2:

The guidance function is segmented into two parts: the lip part provides axial positioning while the hook curl part provides radial guidance. This segmentation allows each part to be optimized for its specific function, enabling thin design without compromising wear resistance.

Inventive Principle:
Principle #1Segmentation

2Ease of operation

If chamfered portions are added to the retainer peripheral edge to prevent interference, then interference is prevented, but the area of the outer peripheral surface is further reduced, increasing surface pressure and wear

Engineering Contradiction:
Improveinterference preventionVSAvoidwear resistance
Core Design Contradiction:
Ease of operationVSReliability

Solution Approach 1:

The invention extracts the guidance function from the retainer's outer peripheral surface (which would otherwise require chamfering) and places it on the hook curl part. This allows the retainer to maintain its full outer peripheral surface area for load-bearing while the hook curl part handles the guidance and interference prevention.

Inventive Principle:
Principle #2Taking out (Extraction)

3Length of moving object

If the thrust bearing is made thin, then it can be used in space-constrained applications, but it becomes more difficult to axially form the lip part and engaging part in a continuous manner

Engineering Contradiction:
Improvethrust bearing thicknessVSAvoidforming difficulty
Core Design Contradiction:
Length of moving objectVSEase of manufacture

Solution Approach 1:

The invention moves the guidance function from the axial direction to the radial direction through the hook curl part. This allows the lip part and engaging part to be formed more easily in the axial direction without compromising the guidance function, thus resolving the manufacturing difficulty.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

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 configuration allows for the creation of a non-separable, thin thrust bearing that effectively manages radial loads and displacements, reducing wear and improving mounting ability, enabling its use in environments with radial loads like eccentricity or centrifugal forces.

Implementation Method 1

the inner peripheral surface of the hook curl part is configured to hold the retainer without separating therefrom by contacting the outer peripheral surface of the retainer in a sliding manner

Methodology Applied
Scientific EffectFriction: Friction

Data Source

PatentEP3176449B1Thrust bearing and manufacturing method for same
Publication Date: 2020.04.22 NSK LTD
  • EP3176449B1 patent drawingFigure 1~2
  • EP3176449B1 patent drawingFigure 3A~3B
  • EP3176449B1 patent drawingFigure 4

AI summary

A thrust bearing (10) comprises: a retainer (13) that is provided with a plurality of pockets (13a); a plurality of rollers (14) that are arranged so as to freely rotate inside the plurality of pockets (13a); and at least one first race (11) that has an annular-shaped first race section (11a) in which the plurality of rollers (14) move. The first race (11) is provided with a hook curl section (11b) that is formed by bending the first race section (11a) from an outer-diameter-side periphery thereof toward the inner-diameter side obliquely in the radial direction, and an outer peripheral surface (13b) of the retainer (13) has a conical surface (13b1) that is formed so as to be substantially parallel to an inner peripheral surface (11c) of the hook curl section (11b). The inner peripheral surface (11c) of the hook curl section (11b) holds the retainer (13) without separating therefrom by contacting the outer peripheral surface (13b) of the retainer (13) in a sliding manner.