Single-Edge Reamer Guide Pad Segmentation for Hole Accuracy

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Solution Overview

Problem

Reamers with a single cutting edge face accuracy issues due to increased friction resistance and potential enlargement of holes, leading to reduced machining accuracy, especially in workpieces with high elasticity.

Innovation Solution

A reamer design with three guide pads positioned strategically around the cutting edge, where the first guide pad is broader than the second and third, and each pad's peripheral face length is optimized to minimize friction and prevent excessive hole enlargement, ensuring accurate machining by distributing cutting resistance effectively.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a large area of the peripheral face of the guide pad contacts the inner face of the machined hole, then the reamer is well supported relative to the machined hole, but the friction resistance (burnishing torque) is increased which reduces machining accuracy

Engineering Contradiction:
Improvesupport stabilityVSAvoidmachining accuracy
Core Design Contradiction:
ReliabilityVSManufacturing precision

Solution Approach 1:

The guide pad is divided into multiple segments (first guide pad, second guide pad, third guide pad) arranged circumferentially around the cutting edge. Each segment contacts the hole inner face at a different location, distributing the support function while reducing the contact area of each individual pad, thereby lowering friction resistance while maintaining overall support stability.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Different guide pads have different peripheral face lengths adapted to their specific positions and functions. The first guide pad has a longer peripheral face for primary support, while the second and third guide pads have shorter peripheral faces to reduce friction. This local optimization allows each pad to contribute appropriately to support stability without collectively generating excessive friction.

Inventive Principle:
Principle #3Local quality

2Device complexity

If the single pad is arranged immediately to the rear of the cutting edge and extends within a continuous range, then the structure is simple, but the pad pushes the hole radially and outwardly causing hole enlargement and reducing machining accuracy

Engineering Contradiction:
Improvestructure simplicityVSAvoidhole dimension accuracy
Core Design Contradiction:
Device complexityVSManufacturing precision

Solution Approach 1:

Instead of a single continuous guide pad, the guide function is segmented into multiple discrete pads positioned at different circumferential locations. This segmentation prevents any single pad from applying excessive radial force that would push and enlarge the hole, while the distributed arrangement maintains structural simplicity and support effectiveness.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The guide pads are arranged asymmetrically with different peripheral face lengths at different positions around the cutting edge. The first guide pad has a longer peripheral face positioned to provide primary support, while the second and third guide pads have shorter peripheral faces positioned to provide additional support without causing hole enlargement. This asymmetric arrangement optimizes the support function while preventing harmful radial forces.

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 reamer improves the straightness and roundness of machined holes by reducing sliding resistance and preventing excessive hole enlargement, maintaining desired dimensions and shape accuracy.

Implementation Method 1

the friction resistance between the two (burnishing torque) is increased

Methodology Applied
Scientific EffectFriction: Friction

Data Source

PatentEP2436470B1reamer
Publication Date: 2017.05.17 TUNGALOY CORP
  • EP2436470B1 patent drawingFigure 1
  • EP2436470B1 patent drawingFigure 2
  • EP2436470B1 patent drawingFigure 3

AI summary

The present invention provides a reamer (10), which has a center axis and includes a single cutting edge (20), provided for a cutting part (14) that is arranged at a leading end side. The reamer (10) includes three guide pads (28, 30, 32) in the cutting part (14). The first guide pad (28) is formed so as to project to the side almost opposite that where the single cutting edge (20) is formed. The second guide pad (30) is arranged in one area (14c) of areas, along a peripheral face of the cutting part (14), that are located between the first guide pad (28) and the single cutting edge (20) and that are directed toward sides opposite each other, and the third guide pad (32) is arranged in the other area (14d).