Shrink-fit Chuck Compensating Section for Concentricity

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Solution Overview

Problem

Shrink chucks face concentricity inaccuracies due to production-related errors in tools or chucks, leading to axial force conversion into radial forces during the heating and shrinking process, causing tool axis tilting and offset from the axis of rotation.

Innovation Solution

A compensating section within the adjusting device, designed with lower hardness and greater elasticity than the shrink-fit chuck, absorbs axial changes and forces, preventing radial force component conversion and maintaining concentricity by adjusting the axial position of the tool before stresses occur.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a length adjustment screw is used to pretension the tool axially after shrinking, then the play between the pull-out protection and the tool is minimized, but production-related errors in the tool or chuck cause axial force to be converted into radial force components, leading to tool axis tilting and concentricity inaccuracies

Engineering Contradiction:
ImproveconcentricityVSAvoidconcentricity accuracy
Core Design Contradiction:
ReliabilityVSManufacturing precision

Solution Approach 1:

The adjusting device performs preliminary axial adjustment of the tool shank before the shrinking process begins. This preliminary action positions the tool correctly in the axial direction, allowing the subsequent shrinking process to occur without generating harmful radial force components that would cause tilting or concentricity errors.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The adjusting device acts as an intermediary mechanism between the tool shank and the shrink chuck. It provides a controlled interface that manages the interaction between the tool and chuck during the shrinking process, preventing direct transmission of harmful radial forces while maintaining proper axial positioning.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Ease of operation

If the clamping section is heated to expand for tool insertion, then the tool shank can be easily inserted into the bore, but the axial shortening during cooling creates axial forces that convert to radial forces, causing tool axis offset

Engineering Contradiction:
Improvetool insertionVSAvoidaxis alignment
Core Design Contradiction:
Ease of operationVSManufacturing precision

Solution Approach 1:

The adjusting device performs preliminary axial adjustment of the tool shank before the shrinking process begins. This preliminary action positions the tool correctly in the axial direction, allowing the subsequent shrinking process to occur without generating harmful radial force components that would cause tilting or concentricity errors.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The adjusting device provides a cushioning mechanism that absorbs and compensates for the axial shortening forces generated during the cooling and shrinking process. This beforehand cushioning prevents these axial forces from being converted into harmful radial force components that would cause tool axis offset.

Inventive Principle:
Principle #11Beforehand cushioning (Prior cushioning)

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 solution effectively compensates for shrinkage-related changes, ensuring high concentricity and minimizing radial deflection, even with small flat errors or coaxial deviations, while allowing coolant supply to the tool.

Implementation Method 1

By heating the clamping section, e.g. B. by induction, the clamping section expands so that the tool shank can be inserted into the mounting hole. As the clamping section cools, it shrinks and forms a high-strength frictional connection with the tool shank.

Methodology Applied
Scientific EffectThermal expansion: Thermal Expansion

Implementation Method 2

As the clamping section cools, it shrinks and forms a high-strength frictional connection with the tool shank.

Methodology Applied
Scientific EffectThermal contraction: Thermal Contraction

Implementation Method 3

the compensating section has a lower hardness and/or greater elasticity than the shrink-fit chuck tool holder, the adjustment section and the shank tool. In this way it can be ensured that the compensating section compensates for the shrinkage-related changes in position and/or location before these lead to stresses in the chuck or in the tool

Methodology Applied
Scientific EffectElasticity: Elasticity

Data Source

PatentEP2408579B1Shrink-fit chuck tool holder
Publication Date: 2020.10.14 GUEHRING KG
  • EP2408579B1 patent drawingFigure 1
  • EP2408579B1 patent drawingFigure 2
  • EP2408579B1 patent drawingFigure 3A~3B

AI summary

The invention relates to an adjusting device for axially supporting a shank tool in a shrink-fit chuck tool holder, comprising a leveling section on the side facing the shank tool to level out or at least reduce any changes in position and/or orientation of the shank tool which are due to shrinkage.