Roller Bearing Surface Treatment With Overlapping Machining and Rolling

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Solution Overview

Problem

Conventional surface treatment methods for rolling bearing components often result in suboptimal surface quality and increased manufacturing effort, with issues such as incomplete processing and unnecessary tool movement, particularly when machining and rolling are performed sequentially rather than simultaneously.

Innovation Solution

A method where a hardened workpiece surface is simultaneously machined and rolled with overlapping tracks, using independently adjustable cutting and rolling tools that oscillate in speed and direction to ensure complete coverage and minimize redundant movement, thereby enhancing surface quality and reducing processing time.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If machining and rolling are performed sequentially with separate setups, then each process can be optimized independently, but the total processing time increases and surface quality deteriorates due to multiple clamping operations

Engineering Contradiction:
Improvesurface qualityVSAvoidprocessing time
Core Design Contradiction:
Manufacturing precisionVSLoss of time

Solution Approach 1:

The patent combines machining and rolling operations into a single setup where both cutting tool and rolling tool work simultaneously on the workpiece. The machining unit performs hard turning while the rolling unit performs surface rolling in the same clamping operation, eliminating the need for separate setups and reducing total processing time while maintaining surface quality

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The patent ensures continuous useful action by having the machining and rolling operations proceed simultaneously without interruption. The workpiece is machined and rolled in one continuous process flow, avoiding idle time between operations and maintaining constant productivity

Inventive Principle:
Principle #20Continuity of useful action

2Manufacturing precision

If the rolling tool follows the same track as the machining tool, then the process is simple to control, but incomplete processing occurs with unaddressed regions between tracks

Engineering Contradiction:
Improvesurface coverageVSAvoidtool movement control
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The patent introduces asymmetric offset between the machining track and rolling track. The rolling tool is positioned at a predetermined offset distance from the machining tool, creating overlapping tracks that ensure complete surface coverage. This asymmetric arrangement prevents unaddressed regions while maintaining manageable control complexity

Inventive Principle:
Principle #4Asymmetry

Solution Approach 2:

The patent employs dynamic adjustment of tool positions and speeds to optimize track overlap. The feeding speeds of the machining and rolling tools are independently controllable, allowing dynamic adaptation of the overlapping pattern to ensure complete coverage while managing control complexity through programmable motion control

Inventive Principle:
Principle #15Dynamics

3Productivity

If the rolling tool moves at the same speed as the machining tool, then the control system is simplified, but redundant tool movement occurs reducing processing efficiency

Engineering Contradiction:
Improveprocessing efficiencyVSAvoidspeed control system
Core Design Contradiction:
ProductivityVSDevice complexity

Solution Approach 1:

The patent implements independent speed control for the machining and rolling tools, allowing each to operate at its optimal speed. The feeding speed of the rolling tool can be adjusted independently from the machining tool, enabling elimination of redundant movements and optimization of processing efficiency without requiring overly complex synchronized control

Inventive Principle:
Principle #15Dynamics

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 achieves a significantly improved surface quality with reduced time expenditure by ensuring all areas are processed without leaving unaddressed regions, while maintaining efficient tool movement and precise control over machining tracks, resulting in longer, uninterrupted groove-shaped structures.

Implementation Method 1

A pressure medium with a hydrostatic pressure in the range of 50 bar to 400 bar acts on the ball

Methodology Applied
Scientific EffectHydrostatic pressure: Pressure Increase

Implementation Method 2

the surface is then subjected to a ball calendering process, i.e., a rolling process, to smooth the ridges of the roughness profile

Methodology Applied
Scientific EffectPlastic deformation: Deformation

Data Source

PatentEP3898079B1Method for surface treatment, roller bearing component and device
Publication Date: 2024.05.08 SCHAEFFLER TECHNOLOGIES AG & CO KG
  • EP3898079B1 patent drawingFigure 1
  • EP3898079B1 patent drawingFigure 2
  • EP3898079B1 patent drawingFigure 3~5

AI summary

According to the invention, a hardened workpiece surface (10) of a workpiece (1) is firstly machined and then rolled, and the machining process, which comprises the material removal process and the rolling process, takes place in the same clamping setup while the workpiece (1) rotates. Both the machining process and the rolling process produce intersecting machining marks (BS, BW), owing to the distance, which is measured in the axial direction (Tr) of the workpiece (1), between the tool (3) used for machining and the tool (12) used for rolling being oscillatingly changed during the machining process.