Multi-Row Bearing Raceway Geometry for Stable Axial Groove Measurement

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Solution Overview

Problem

Existing multi-row bearings face challenges in accurately and efficiently measuring the axial dimension between raceway grooves, leading to instability in machining precision and increased labor and cost due to frequent disassembly for measurement.

Innovation Solution

A multi-row bearing design with outer ring raceway grooves formed on both sides of the groove bottom, allowing for stable installation of a measuring tool that accurately measures the axial dimension between grooves, enabling high-precision machining without frequent disassembly.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If the outer ring raceway groove is formed only from the groove bottom to the groove shoulder on one side, then the bearing structure is simpler, but the measuring tool cannot be stably installed and measurement becomes unstable

Engineering Contradiction:
Improveease of forming raceway grooveVSAvoidstability of measurement
Core Design Contradiction:
Ease of manufactureVSMeasurement precision

Solution Approach 1:

The patent applies asymmetry by forming the outer ring raceway groove only on one side of the groove bottom, creating an asymmetric structure where the groove is positioned asymmetrically relative to the groove bottom. This asymmetric configuration allows the measuring tool to be stably installed by engaging with the groove shoulders on both sides of the groove, thereby achieving stable measurement of the axial dimension between raceway grooves.

Inventive Principle:
Principle #4Asymmetry

2Measurement precision

If measurement is performed by removing the workpiece from the processing machine, then measurement can be performed, but the processing method requires very cost and labor

Engineering Contradiction:
Improveability to measure axial dimensionVSAvoidprocessing efficiency
Core Design Contradiction:
Measurement precisionVSProductivity

Solution Approach 1:

The patent applies self-service by designing the raceway groove structure to enable the workpiece to serve its own measurement function. The groove is formed to allow measuring tools to be stably installed and perform measurements directly on the workpiece while it remains on the processing machine, eliminating the need for repeated removal and attachment operations.

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The patent applies preliminary action by pre-forming the raceway groove with specific geometric characteristics that facilitate stable measurement. The groove is designed in advance to provide engagement surfaces for measuring tools, enabling measurements to be performed without removing the workpiece from the processing machine.

Inventive Principle:
Principle #10Preliminary action

3Ease of operation

If the measuring tool is engaged with the raceway groove, then measurement can be performed, but the measurement value becomes unstable when the groove is formed only on one side

Engineering Contradiction:
Improveease of installing measuring toolVSAvoidstability of measurement value
Core Design Contradiction:
Ease of operationVSReliability

Solution Approach 1:

The patent applies asymmetry by forming the outer ring raceway groove only on one side of the groove bottom, creating an asymmetric structure where the groove is positioned asymmetrically relative to the groove bottom. This asymmetric configuration allows the measuring tool to be stably installed by engaging with the groove shoulders on both sides of the groove, thereby achieving stable measurement of the axial dimension between raceway grooves.

Inventive Principle:
Principle #4Asymmetry

Data Source

PatentEP4317720B1Multi-row bearing and bearing unit
Publication Date: 2026.04.15 NSK LTD
  • EP4317720B1 patent drawingFigure 1
  • EP4317720B1 patent drawingFigure 2
  • EP4317720B1 patent drawingFigure 3A~3B

AI summary

Provided are a multi-row bearing and a bearing unit including the multi-row bearing in which an axial dimension between raceway grooves can be accurately and easily measured at a short time, and the raceway grooves can be further machined with high dimensional accuracy. In a multi-row bearing (10), an inner ring raceway groove (31a) at one end portion in an axial direction is formed over groove shoulders on both sides in the axial direction with respect to a groove bottom, and an inner ring raceway groove (31b) at an intermediate portion in the axial direction is formed over a groove shoulder on one side in the axial direction from a groove bottom. In addition, an outer ring raceway groove (21a) at the other end portion in the axial direction is formed over groove shoulders on both sides in the axial direction with respect to a groove bottom, and an outer ring raceway groove (21b) at the intermediate portion in the axial direction is formed over a groove shoulder on one side in the axial direction from a groove bottom.