Shrink-Fit Tool Holder Coolant Jacket for High-Speed Machining

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Solution Overview

Problem

Existing tool holder devices with shrink-fit chucks face challenges in providing reliable coolant supply at high rotational speeds, as the coolant jet detaches from the tool, and existing designs often require excessive coolant throughput and high pump capacities, leading to inefficient cooling and potential coolant jet dispersion.

Innovation Solution

A tool holder device with a conically widening inner chamfer at the free end and a storage/collection space for coolant, allowing the coolant to exit as a closed or essentially closed coolant jacket around the tool shank, utilizing annular gaps and strategically designed flat grooves to guide coolant effectively and minimize jet expansion.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Shape

If narrow grooves are used in the shrink-fit chuck, then the coolant exits in the form of three separate jets, but reliable cooling of the tool in the cutting/machining area is not ensured and the coolant jet detaches from the tool at high rotational speeds

Engineering Contradiction:
Improvegroove cross-section shapeVSAvoidcoolant supply reliability
Core Design Contradiction:
ShapeVSReliability

Solution Approach 1:

The coolant supply channel is divided into multiple longitudinal grooves (typically three) distributed around the inner circumference of the receiving bore. Each groove acts as an independent coolant jet source, collectively forming a comprehensive cooling coverage around the tool shank.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The grooves are designed with specific dimensional characteristics (width, depth, spacing) to optimize coolant flow properties. The groove cross-section and positioning are tailored to ensure the coolant jets remain attached to the tool surface at high rotational speeds while providing effective cooling at the cutting area.

Inventive Principle:
Principle #3Local quality

2Ease of operation

If coolant is guided through slots in the collet past the tool shank to the free end face, then coolant can escape through an annular gap, but the coolant discharge into the open air is relatively undefined and cannot ensure a clean cooling water jet flow along the tool

Engineering Contradiction:
Improvecoolant escape mechanismVSAvoidcoolant jet flow shape
Core Design Contradiction:
Ease of operationVSShape

Solution Approach 1:

The annular gap formed by the outlet opening and tool shank acts as an intermediary structure that shapes and directs the coolant flow. This gap geometry serves as a flow guide that maintains a defined, clean coolant jet pattern as it exits the tool holder device.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Object-affected harmful factors

If a baffle plate is used to define a storage or collection space for the coolant outside the receiving opening, then a coolant storage space can be created, but additional installation space in the direction of the longitudinal axis is required

Engineering Contradiction:
Improvecoolant flow controlVSAvoidtool holder device length
Core Design Contradiction:
Object-affected harmful factorsVSLength of moving object

Solution Approach 1:

The storage and/or collection space for coolant is integrated within the tool holder device body, nesting the coolant reservoir function inside the existing structural volume. This eliminates the need for external baffle plates and additional axial space, as the coolant storage is accommodated within the receiving bore area.

Inventive Principle:
Principle #7Nested doll (Nesting)

4Quantity of substance

If a considerable coolant flow rate is required for the tool holder device, then high pumping capacities are necessary for the coolant pumps

Engineering Contradiction:
Improvecoolant flow rateVSAvoidpump capacity
Core Design Contradiction:
Quantity of substanceVSUse of energy by moving object

Solution Approach 1:

The coolant flow is segmented into multiple longitudinal grooves, distributing the total flow rate across several parallel channels. This segmentation improves flow distribution efficiency and reduces the energy required for pumping compared to a single large-flow channel.

Inventive Principle:
Principle #1Segmentation

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

Ensures efficient coolant supply to the cutting area with reduced coolant volume flow, maintaining effective cooling even at high speeds and preventing coolant dispersion, while allowing for longer tool lengths without excessive restrictions.

Implementation Method 1

even at high rotational speeds and under the influence of centrifugal forces

Methodology Applied
Scientific EffectCentrifugal force: Centrifugal Force

Implementation Method 2

a closed or substantially closed coolant jacket, which rests against the shank of the tool or the tool itself

Methodology Applied
Scientific EffectFluid flow along surface: Boundary Layer

Data Source

PatentEP2666569B1Tool holder device
Publication Date: 2022.09.28 FRANZ HAIMER MASCHINENBAU KG
  • EP2666569B1 patent drawingFigure 1~1a
  • EP2666569B1 patent drawingFigure 2~2a
  • EP2666569B1 patent drawingFigure 3~3a

AI summary

The tool holding device (1) has a tool holding body (2) for torque proof holding of a rotation tool (5) with a shaft (5'). A coolant controlling system (12) is formed as a flat groove at an inner side (9) of a receiving opening (7). A coolant accumulation chamber or collecting chamber is connected with the periphery of the tool holding device by an annular space.