Segmented Hob Cutter Assembly for Precision and Shock Resistance

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Solution Overview

Problem

Shank-type hob cutters made from sintered carbide are sensitive to shocks and costly, requiring frequent replacement, while bore-type designs lack precision and flexibility in mounting conditions.

Innovation Solution

The hob cutter arrangement features end shank pieces with axial blind holes and complementary threads, elastic elements for biasing, and a hollow shaft taper interface, allowing direct coupling with the cutting machine spindle and enabling interchangeable cutting parts made from hardened steel, reducing manufacturing costs and environmental impact.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If shank-type design is used for hob cutters made from sintered carbide, then high precision and truth of running are achieved, but manufacturing cost increases and the tool becomes sensitive to shocks requiring frequent replacement

Engineering Contradiction:
Improvetruth of runningVSAvoidsensitivity to shocks
Core Design Contradiction:
Manufacturing precisionVSReliability

Solution Approach 1:

The hob cutter is divided into separate components: a tool body made from sintered carbide for precision cutting, and shank portions made from more shock-resistant materials. The tool body contains an axial bore that receives the shank portions, allowing the cutting portion to maintain high precision while the shank portions provide shock resistance and durability.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The invention uses composite construction by combining sintered carbide material for the tool body with different materials for the shank portions. This allows each component to be made from materials optimized for its specific function: sintered carbide for cutting precision and other materials for shank durability and shock resistance.

Inventive Principle:
Principle #40Composite materials

2Reliability

If bore-type design is used for hob cutters, then manufacturing cost is reduced and shock resistance is improved, but manufacturing precision and truth of running deteriorate

Engineering Contradiction:
Improveshock resistanceVSAvoidtruth of running
Core Design Contradiction:
ReliabilityVSManufacturing precision

Solution Approach 1:

The hob cutter is divided into separate components: a tool body made from sintered carbide for precision cutting, and shank portions made from more shock-resistant materials. The tool body contains an axial bore that receives the shank portions, allowing the cutting portion to maintain high precision while the shank portions provide shock resistance and durability.

Inventive Principle:
Principle #1Segmentation

3Manufacturing precision

If shank-type design with sintered carbide is used, then high precision is achieved, but device complexity and manufacturing expenditure increase

Engineering Contradiction:
Improvetruth of runningVSAvoidmanufacturing expenditure
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The hob cutter is divided into separate components: a tool body made from sintered carbide for precision cutting, and shank portions made from more shock-resistant materials. The tool body contains an axial bore that receives the shank portions, allowing the cutting portion to maintain high precision while the shank portions provide shock resistance and durability.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The invention changes the material parameter for different portions of the hob cutter. The tool body uses sintered carbide for precision, while the shank portions use different materials optimized for their function, reducing overall manufacturing complexity and cost.

Inventive Principle:
Principle #35Parameter changes

4Adaptability or versatility

If interchangeable cutting parts are enabled, then adaptability and ease of repair are improved, but device complexity increases

Engineering Contradiction:
Improveinterchangeability of cutting partsVSAvoidassembly structure
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The hob cutter is divided into separate components: a tool body made from sintered carbide for precision cutting, and shank portions made from more shock-resistant materials. The tool body contains an axial bore that receives the shank portions, allowing the cutting portion to maintain high precision while the shank portions provide shock resistance and durability.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The standardized interface design with axial bores and conical sections allows the same shank portions to be used with different cutting parts, and different shank portions to be used with the same tool body, creating a universal system that improves adaptability and ease of repair.

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

This design ensures high precision and flexibility in mounting, reduces manufacturing costs, and allows for standardization and weight reduction by enabling the use of hardened steel for drive and guide shank pieces, facilitating easy replacement of cutting parts and direct user assembly.

Implementation Method 1

elastic elements which are clamped between the front sides of the center section with the greatest diameter of the axle and the foremost front sides of the cone sections of the end shank pieces, the elastic elements biasing the shank pieces with a force acting away from the center section of the axle

Methodology Applied
Scientific EffectElasticity: Elasticity

Data Source

PatentEP3936270B1Hob cutter arrangement
Publication Date: 2022.10.26 DIAMETAL
  • EP3936270B1 patent drawingFigure 1
  • EP3936270B1 patent drawingFigure 2
  • EP3936270B1 patent drawingFigure 3~4

AI summary

Hob cutter arrangement with a tool body (2.1), which has a continuous axial bore (2.6), conical bore sections (2.7) forming both ends of the axial bore (2.6), an end shank body (2.2, 2.3), respectively, at each end of the tool body (2.1), adapted for coupling with the hobbing machine, and a conical section inserted fittingly into the conical bore section (2.7). Each end shank body (2.2, 2.3) has a radial flange (2.19) which can be placed against the end face (2.8) of the tool body and a shaft section on the side of the flange (2.19) opposite the conical section for clamping in a machine tool. An axle (2.10) connects the end shank bodies (2.2, 2.3) and clamps them together. The end shank bodies (2.2, 2.3) are provided with blind holes (2.14) opening towards the axle (2.10) and provided with complementary threads to the axle (2.10). Elastic elements (2.20) are clamped between a central section of the axle (2.10) and the front side of the end shank body (2.2, 2.3) on both sides of the axle (2.10).