Expandable Honing Tool for Bore Position Correction

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Solution Overview

Problem

Conventional honing methods require significant structural effort in the construction of processing machines and honing tools to correct hole positions, and they often lead to permanent deformation of unstable workpieces.

Innovation Solution

A honing method using an expandable ring-shaped honing tool with a plurality of cutting material bodies distributed around the circumference, which is rigidly coupled to a work spindle, allowing for relative positioning and expansion to correct the bore position without permanent deformation, utilizing a coaxial tool axis to maintain orientation under transverse forces and achieve precise centering.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If conventional honing methods are used to correct hole positions, then position correction can be achieved, but significant structural effort is required in the construction of processing machines and honing tools

Engineering Contradiction:
Improvehole position correctionVSAvoidstructural effort in machine and tool construction
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The honing tool is designed with expandable cutting elements that can dynamically adjust their radial position. The cutting elements are arranged in a ring-shaped configuration that can expand and contract, allowing the tool to adapt to different bore sizes and positions without requiring complex machine construction. This dynamic expansion mechanism enables position correction while reducing structural complexity.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The honing tool is divided into multiple discrete cutting elements arranged around the circumference in a ring-shaped configuration. Each cutting element can independently expand and contract, allowing distributed material removal across the bore surface. This segmentation enables precise position correction through coordinated movement of individual cutting elements, reducing the need for complex overall tool construction.

Inventive Principle:
Principle #1Segmentation

2Manufacturing precision

If conventional honing methods are used to correct hole positions, then position correction can be achieved, but permanent deformation of unstable workpieces occurs

Engineering Contradiction:
Improvehole position correctionVSAvoidworkpiece deformation
Core Design Contradiction:
Manufacturing precisionVSReliability

Solution Approach 1:

The expandable ring-shaped honing tool allows controlled, progressive expansion of cutting elements during the honing process. This dynamic expansion enables the tool to gently engage with the workpiece material, correcting position through gradual material removal rather than forceful engagement that causes deformation. The controlled expansion mechanism prevents excessive cutting forces that would deform unstable workpieces.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The honing process utilizes controlled changes in the radial position parameter of the cutting elements through expansion and contraction. By progressively adjusting the expansion parameter of the ring-shaped tool, the process achieves position correction through controlled material removal. This parameter control allows the tool to work with unstable workpieces without causing permanent deformation, as the cutting action is gradually applied rather than abruptly.

Inventive Principle:
Principle #35Parameter changes

3Device complexity

If expandable ring-shaped honing tool is used, then structural effort is reduced, but material removal rate and cutting forces need to be optimized

Engineering Contradiction:
Improvestructural effortVSAvoidmaterial removal rate
Core Design Contradiction:
Device complexityVSProductivity

Solution Approach 1:

The expandable ring-shaped honing tool achieves high material removal rates through dynamic expansion of the cutting elements. When the tool expands to its full diameter, all cutting elements engage simultaneously with the bore surface, maximizing material removal capacity. This dynamic expansion mechanism provides high productivity without requiring complex structural support, as the expansion motion itself generates the necessary cutting forces.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

Multiple cutting elements are combined in a ring-shaped configuration that expands and contracts as a unified structure. This merging of cutting elements allows simultaneous material removal across the entire bore circumference when fully expanded. The combined cutting action of all elements in the ring provides high material removal rates while maintaining a relatively simple overall tool structure compared to individual cutting element designs.

Inventive Principle:
Principle #5Merging (Combining)

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 method allows for precise correction of bore position with reduced structural effort, avoiding permanent deformation and improving precision, while enabling high material removal rates with lower cutting forces and better cooling lubricant supply, thus producing centered and circular-cylindrical bores efficiently.

Implementation Method 1

material-removing engagement of cutting material bodies on the inside of the bore

Methodology Applied
Scientific EffectAbrasion: Abrasion

Data Source

PatentEP3148745B1Honing process for fine machining of bores
Publication Date: 2019.07.03 ELGAN DIAMANTWERKZEUGE
  • EP3148745B1 patent drawingFigure 1
  • EP3148745B1 patent drawingFigure 2A~2B
  • EP3148745B1 patent drawingFigure 3A~3F

AI summary

In a honing method for machining the inner face of a bore (122) in a workpiece (120) by means of at least one honing operation, an expandable honing tool is used in a honing operation, said expandable honing tool having an expandable annular cutting group (220) having a plurality of cutting material bodies distributed around the circumference of the tool body in an end region of the tool body that is remote from the spindle, the axial length of said cutting material bodies being less than the effective outside diameter of the cutting group with the cutting material bodies fully retracted. The method is characterized by the following steps of: rigidly coupling the honing tool to a work spindle of a machine tool; positioning the honing tool and the bore relative to one another such that a tool axis (212) of the honing tool is coaxial with a setpoint position (SB) of the bore axis of the bore; introducing the honing tool into the bore, with the cutting material bodies retracted, as far as an insertion end position in which the cutting group is located in an end region (123), remote from the entry, of the length to be machined of the bore; rotating the honing tool and simultaneously expanding the cutting group, at or in the region of the insertion end position, as far as a first radial position of the cutting material bodies such that, by material-removing engagement of cutting material bodies with the inner side of the bore, a cylindrical widening (121) of the bore is produced in the end region of the bore, said cylindrical widening (121) being centred substantially with respect to the setpoint position of the bore axis; withdrawing the honing tool from the bore while simultaneously rotating the honing tool such that the bore is widened, starting from the cylindrical widening, successively in the direction of the entry side.