Deburring Tool Motion for Burr-Free Opposite-Side Through-Holes

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Solution Overview

Problem

The production of crankshaft oil bores often results in burrs at the opening facing away from the tool, which can loosen during vehicle operation, causing damage to internal combustion engines due to geometric constraints and existing deburring methods being inefficient.

Innovation Solution

A method involving a deburring process where a deburring tool is used in a plunge stroke and counter-rotating deburring stroke to remove burrs from the bore mouth facing away from the tool, with adjustable deburring blades and optional peeling blades to ensure a smooth, burr-free finish, even in inclined bore geometries.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a second oil passage is drilled into the crankshaft to connect with the first oil passage, then the oil passage system is completed, but a burr is formed at the end of the second passage on the side opposite the tooling

Engineering Contradiction:
Improveoil passage system completenessVSAvoidburr formation
Core Design Contradiction:
ReliabilityVSObject-generated harmful factors

Solution Approach 1:

A countersink is created at the bore opening on the side opposite the tooling before the drilling process. This preliminary action provides a recess that captures burrs during subsequent drilling operations, preventing them from becoming loose harmful factors in the oil passage system.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The burr formation, which is normally a harmful byproduct of drilling, is converted into a beneficial feature by having it deposit into the pre-created countersink. The harmful burr material now serves to fill and seal the countersink recess, ensuring complete coverage and preventing burr ejection during operation.

Inventive Principle:
Principle #22Blessing in disguise (Convert harm into benefit)

2Object-generated harmful factors

If a deburring tool is used to remove burrs from the bore opening on the side opposite the tool, then the burr is removed, but the process requires complex multi-step operations including plunge stroke and counter-rotating deburring stroke

Engineering Contradiction:
Improveburr removalVSAvoiddeburring process complexity
Core Design Contradiction:
Object-generated harmful factorsVSDevice complexity

Solution Approach 1:

The harmful burr is extracted from the bore opening during the drilling process itself through the countersink mechanism, rather than requiring a separate deburring operation. The burr is taken out and deposited into the countersink recess, eliminating the need for complex post-drilling deburring strokes.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The countersink creation and burr capture functions are merged into a single preliminary operation performed before drilling. This combines what would otherwise be separate processes (countersinking and burr removal) into one integrated step, simplifying the overall manufacturing process.

Inventive Principle:
Principle #5Merging (Combining)

3Object-generated harmful factors

If the bore opening is deburred using conventional methods, then the burr is removed, but the process time is extended due to multiple strokes and tool movements

Engineering Contradiction:
Improveburr eliminationVSAvoiddeburring process duration
Core Design Contradiction:
Object-generated harmful factorsVSLoss of time

Solution Approach 1:

The countersink is prepared in advance before drilling, so that burr capture is already in place. This preliminary action eliminates the need for time-consuming post-drilling deburring operations, as burrs are automatically captured during the drilling process itself.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The process skips the traditional multi-step deburring sequence (plunge stroke, counter-rotating stroke, withdrawal) by using the countersink to capture burrs during the drilling operation. This rushes through the burr removal function in a single integrated operation rather than multiple sequential steps.

Inventive Principle:
Principle #21Skipping (Rushing through)

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 method effectively prevents burr formation and ensures a smooth, cylindrical hole wall, reducing the risk of engine damage by efficiently deburring the bore mouth, even in complex geometries, and shortening the deburring process duration.

Implementation Method 1

a counter-rotating deburring stroke is performed in which the deburring tool is inserted into the bore opening on the side opposite the tool at a deburring speed, so that a burr at the bore opening on the side opposite the tool is pulled inwards and deburred by the deburring cutting edge

Methodology Applied
Scientific EffectFriction: Friction

Data Source

PatentEP4035812A1Method for manufacturing a workpiece through hole and deburring tool
Publication Date: 2022.08.03 AUDI AG
  • EP4035812A1 patent drawingFigure 1
  • EP4035812A1 patent drawingFigure 2
  • EP4035812A1 patent drawingFigure 3~4

AI summary

The invention relates to a method for producing a workpiece through-hole (7) with a deburring process in which a bore opening (45) of the workpiece through-hole (7) facing away from the tool is deburred by means of at least one deburring cutting edge (13) of a deburring tool (9). According to the invention, an immersion stroke (N) is performed in which the deburring tool (9) is drawn into the workpiece through-hole (7) from the bore opening (49) facing the tool towards the bore opening (45) facing away from the tool. In addition, a counter-rotating deburring stroke (A) is performed, in which the deburring tool (9) is inserted into the bore opening (45) opposite the tool at a deburring speed (nA), so that a burr (14) at the bore opening (45) opposite the tool is pulled inwards and deburred by means of the deburring cutting edge (13) of the deburring tool (9).