Cavity Tool Holder Structure for Vibration-Damped Clamping

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Solution Overview

Problem

Conventional tool holders experience vibrations due to reaction forces from cutting edges, leading to reduced machining performance, as existing damping methods often compromise precision or suffer from leakage issues with hydraulic pressure.

Innovation Solution

A tool holder design featuring integrally molded cavities within the clamping section that provide excellent damping properties without the need for external covers or welding, allowing for precise control of hydraulic pressure and improved vibration management.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If conventional tool holders are used to clamp tools, then the tool can be securely held, but vibrations occur due to reaction forces from cutting edges that excite resonance

Engineering Contradiction:
Improvetool clamping reliabilityVSAvoidvibrations
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The tool holder incorporates porous damping material within its structure, specifically in the form of cavities filled with viscoelastic material. This porous structure absorbs vibration energy and dampens resonant frequencies caused by cutting forces, reducing harmful vibrations while maintaining structural integrity and tool clamping reliability

Inventive Principle:
Principle #31Porous materials

Solution Approach 2:

The tool holder uses composite construction combining rigid structural materials with viscoelastic damping materials. The composite structure integrates metal components for strength and clamping force with polymer-based damping material in the cavities, creating a multi-material system that simultaneously provides structural support and vibration damping

Inventive Principle:
Principle #40Composite materials

2Object-affected harmful factors

If damping material is added to reduce vibrations, then vibration damping improves, but the structural integrity and precision may be compromised

Engineering Contradiction:
Improvevibration dampingVSAvoidmachining precision
Core Design Contradiction:
Object-affected harmful factorsVSManufacturing precision

Solution Approach 1:

The damping material is strategically placed in specific cavities within the tool holder structure rather than throughout the entire component. This localized application provides vibration damping in critical areas while maintaining structural rigidity and precision in other regions, ensuring machining accuracy is preserved

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The tool holder is segmented into distinct functional zones: rigid structural sections for precision and strength, and cavity regions filled with damping material for vibration control. This segmentation allows each zone to optimize its specific function without compromising the overall system performance

Inventive Principle:
Principle #1Segmentation

3Force

If hydraulic pressure is used for clamping, then clamping force is improved, but leakage issues occur under high pressure

Engineering Contradiction:
Improveclamping forceVSAvoidsealing reliability
Core Design Contradiction:
ForceVSReliability

Solution Approach 1:

The hydraulic system incorporates self-sealing features where the high pressure itself enhances the sealing action. The pressure-activated sealing mechanism automatically increases sealing force under high pressure conditions, preventing leakage without requiring additional sealing components or active control systems

Inventive Principle:
Principle #25Self-service

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 holder effectively reduces vibrations, maintains machining precision, and ensures reliable sealing under high hydraulic pressures, enhancing overall system performance.

Implementation Method 1

it has been shown that a cavity that is completely enclosed and formed entirely within a pre-formed section exhibits excellent damping properties

Methodology Applied
Scientific EffectVibration damping: Damping

Implementation Method 2

This sleeve section of the tool holder can be expanded radially by heating to such an extent that the cold shank of the tool can be inserted into or withdrawn from the sleeve section

Methodology Applied
Scientific EffectThermal expansion: Thermal Expansion

Implementation Method 3

Once the sleeve section has cooled down again, a press fit forms between it and the shank of the tool

Methodology Applied
Scientific EffectThermal contraction: Thermal Contraction

Data Source

PatentEP2934800B1Tool holder with built-in cavities
Publication Date: 2023.05.10 FRANZ HAIMER MASCHINENBAU KG
  • EP2934800B1 patent drawingFigure 1~2
  • EP2934800B1 patent drawingFigure 3~6
  • EP2934800B1 patent drawingFigure 7~9

AI summary

A tool holder (1) has a main body (2) for coupling the tool holder (1) to the spindle of a machine-tool and a clamping section (3) connected thereto for clamping a tool, and is characterised in that the tool holder (1) has at least one section shaped in a single piece by primary shaping and having one or more inner cavities (9) that form an enclave in the section shaped by primary shaping.