Detachable Reaming Cutter With Oil-Storing Guide for Precise Hole Finishing

Resolve Bottlenecks,
Find Innovative Solutions
Generate Solutions

Solution Overview

Problem

Conventional hole finishing tools face challenges in achieving high precision due to insufficient rigidity, particularly when used with handheld tools, and excessive use of expensive materials like cemented carbide, which complicates the process and requires continuous lubrication oil supply to manage friction and thermal expansion.

Innovation Solution

A hole finishing tool comprising a reaming cutter and a holder with a detaching structure for cutting oil flow paths, a sliding portion with no back taper for reduced friction, and concave portions for storing lubrication oil, allowing for precise hole finishing without relying on high spindle rigidity and minimizing expensive material usage.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If a reamer is made of cemented carbide to secure high rigidity and processing accuracy, then manufacturing precision is improved, but device complexity and material cost increase

Engineering Contradiction:
Improvehole finishing accuracyVSAvoidtool structure complexity
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The reamer is divided into a holder body and detachable cutting edges. The holder can be made of simpler, less expensive material while the cutting edges use cemented carbide only where needed for cutting, reducing overall material complexity while maintaining precision at the cutting interface.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Cemented carbide material is applied locally only to the cutting edges where high precision and rigidity are critical, rather than the entire tool. This allows high manufacturing precision at the functional interface while reducing overall device complexity and material cost.

Inventive Principle:
Principle #3Local quality

2Loss of substance

If exchange-type cutting edges are used to reduce cemented carbide usage, then material cost is reduced, but finishing accuracy deteriorates due to insufficient rigidity of handheld tools

Engineering Contradiction:
Improvecemented carbide usageVSAvoidhole finishing accuracy
Core Design Contradiction:
Loss of substanceVSManufacturing precision

Solution Approach 1:

The tool is segmented into a rigid holder body and detachable cutting edges. The holder provides the necessary rigidity structure while the cutting edges are exchanged as needed, allowing reduced cemented carbide usage overall while maintaining precision through the rigid holder structure.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The holder acts as an intermediary between the handheld tool and the cutting edges. It provides a rigid interface that compensates for the insufficient rigidity of handheld tools, ensuring finishing accuracy is maintained even when using exchangeable cutting edges with less cemented carbide.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Reliability

If lubrication oil is continuously supplied from the inside of the drill to the clearance between the drill and positioning bush, then friction and thermal expansion are managed, but lubrication oil scatters before the discharge port is inserted into the positioning bush

Engineering Contradiction:
Improvefriction and thermal managementVSAvoidlubrication oil scattering
Core Design Contradiction:
ReliabilityVSObject-generated harmful factors

Solution Approach 1:

The lubrication oil supply function is extracted from the internal drill flow path and relocated to an external supply system. This allows lubrication oil to be supplied directly to the positioning bush clearance without passing through the drill interior, preventing scattering while maintaining friction and thermal management.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

A dedicated lubrication oil supply path acts as an intermediary system, delivering lubrication oil directly to the clearance between the tool and positioning bush without using the drill's internal flow path. This eliminates the scattering problem while maintaining effective lubrication for friction and thermal management.

Inventive Principle:
Principle #24Intermediary (Mediator)

4Object-generated harmful factors

If a newly supply path dedicated for lubrication oil is created to supply lubrication oil from the outside into the inside of the positioning bush, then lubrication oil scattering is prevented, but device complexity increases

Engineering Contradiction:
Improvelubrication oil scatteringVSAvoidtool structure complexity
Core Design Contradiction:
Object-generated harmful factorsVSDevice complexity

Solution Approach 1:

The holder structure is designed to serve multiple functions: it holds the cutting edges, provides rigidity, and incorporates the lubrication oil supply path. By integrating the lubrication function into the existing holder structure rather than adding a separate external system, device complexity is minimized while preventing lubrication oil scattering.

Inventive Principle:
Principle #6Universality (Multi-functionality)

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 tool enables high-precision hole finishing with reduced material costs and simplified structure, maintaining accuracy even with handheld tools by using lubrication oil stored in concave portions to reduce friction and prevent clogging, while allowing for deeper hole completion with improved processing accuracy.

Implementation Method 1

The sliding portion has a concave portion for storing lubrication oil

Methodology Applied
Scientific EffectFriction reduction through lubrication: Lubrication

Implementation Method 2

The first flow path for ejecting cutting oil is formed inside the reaming cutter

Methodology Applied
Scientific EffectFluid flow for cooling and lubrication: Fluid Spray

Implementation Method 3

The second flow path for supplying the cutting oil to the first flow path is formed inside the holder

Methodology Applied
Scientific EffectFluid flow through connected pathways: Fluid Spray

Data Source

PatentEP3915705A1Hole finishing tool and method for producing a finished hole
Publication Date: 2021.12.01 SUBARU CORP
  • EP3915705A1 patent drawingFigure 1~3
  • EP3915705A1 patent drawingFigure 4~6
  • EP3915705A1 patent drawingFigure 7~8

AI summary

Reaming cutter (2) mounted to a holder (3). The reaming cutter (1) has a male screw (5C). A first flow path (8A) for cutting oil is formed inside the reaming cutter (2). The holder (3) has a female screw (5D) for receiving the male screw (5C) of reaming cutter (2). A second flow path (8B) for supplying the cutting oil to the first flow path (8A) is formed inside the holder (2). The holder has a shank (6) for being held by a tool rotating device (20). The holder has a sliding portion (9) for cooperating with a guide bush (4).The sliding portion (9) is inserted into the positioning bush (4) and held slidingly. The sliding portion (9) has a concave portion (10) for storing lubrication oil.