Oil-Hole Reamer Outlet Layout for High-Feed Hole Finishing

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Solution Overview

Problem

Existing reamers fail to achieve high accuracy in finishing the inner circumference of pilot holes during high-feed machining due to interference of cutting chips with the flow of cutting oil, leading to roughness of the inner surface.

Innovation Solution

The oil hole reamer is designed with an oil outlet opening towards the position where the tip cutting edge intersects the outer-circumference cutting edge, allowing cutting oil to form a film along the inner surface, effectively lubricating and cooling this corner, thereby facilitating smooth chip discharge and high-accuracy finishing.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the oil hole is positioned to lubricate the corner where tip cutting edge intersects outer-circumference cutting edge, then lubrication effectiveness is improved, but chip discharge may be hindered

Engineering Contradiction:
Improvelubrication effectivenessVSAvoidchip interference
Core Design Contradiction:
ReliabilityVSObject-generated harmful factors

Solution Approach 1:

The oil outlet is positioned at a specific location corresponding to the corner where the tip cutting edge intersects the outer-circumference cutting edge, providing localized lubrication exactly where needed. This local quality approach ensures that cutting oil is delivered precisely to the high-stress intersection point without broadly affecting chip flow paths.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The oil hole is configured to extend obliquely rather than radially outward, changing the dimensionality of oil delivery. This oblique orientation allows the oil outlet to open toward the corner position while directing cutting oil in a manner that forms a lubricating film along the inner surface without blocking the axial chip discharge path.

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

2Productivity

If high-feed machining is performed to increase productivity, then machining efficiency is improved, but surface accuracy deteriorates due to chip interference with cutting oil flow

Engineering Contradiction:
Improvemachining efficiencyVSAvoidsurface accuracy
Core Design Contradiction:
ProductivityVSManufacturing precision

Solution Approach 1:

Cutting oil is delivered to the corner region in advance of chip formation and accumulation, creating a lubricating film on the inner surface before chips can interfere with the oil flow. This preliminary lubrication action ensures that even during high-feed machining, the surface maintains accuracy because the cutting zones are pre-lubricated and chips are directed away from the oil flow path.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The obliquely extending oil hole acts as an intermediary structure that decouples the lubrication function from the chip discharge path. By directing cutting oil through this intermediate oblique pathway, the system enables high-feed machining with improved surface accuracy, as the oil delivers lubrication without being blocked by chips.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Productivity

If the outer-circumference flank face has a smaller diameter at the back to enhance cutting performance, then cutting efficiency is improved, but tool structure complexity increases

Engineering Contradiction:
Improvecutting efficiencyVSAvoidtool structure
Core Design Contradiction:
ProductivityVSDevice complexity

Solution Approach 1:

The outer-circumference flank face is designed with asymmetric diameter variation, being smaller at the tool-rotation-direction back than at the front. This asymmetric configuration optimizes cutting performance by reducing interference and improving chip flow in the critical cutting zone, while the simplicity of the gradual diameter change keeps the overall tool structure relatively simple.

Inventive Principle:
Principle #4Asymmetry

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 design enables high-accuracy finishing of pilot hole inner circumferences even during high-feed machining by preventing chip interference and ensuring effective lubrication and cooling, minimizing cutting resistance and thermal issues.

Implementation Method 1

an oil outlet of the oil hole is formed to be open toward a position corresponding to a corner at which the tip cutting edge intersects the outer-circumference cutting edge and to cause at least part of the oil outlet to be open to the outer-circumference flank face

Methodology Applied
Scientific EffectLubrication: Lubrication

Data Source

PatentEP3868504B1Reamer with oil hole
Publication Date: 2026.04.22 SUMITOMO ELECTRIC TOOL NET INC
  • EP3868504B1 patent drawingFigure 1
  • EP3868504B1 patent drawingFigure 2
  • EP3868504B1 patent drawingFigure 3

AI summary

An oil hole reamer includes an oil passage extending inside a tool main body along an axis of the tool main body, and an oil hole extending radially outward from the oil passage to an outer circumference of the tool main body. An oil outlet of the oil hole is formed to be open toward a position corresponding to a corner at which a tip cutting edge intersects an outer-circumference cutting edge and to cause at least part of the oil outlet to be open to the outer-circumference flank face.