Tool Holder Flat Grooves Coolant Envelope High Speed
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Solution Overview
Problem
Existing tool holding devices, such as shrink fit chucks and collet chucks, face challenges in providing reliable coolant guidance to the cutting region, especially at high rotation speeds, leading to coolant separation and inefficient cooling due to narrow grooves and excessive coolant flow rates.
Innovation Solution
The tool holding device features flat grooves on its inner surface that widen towards the free end, forming a coolant reservoir and annular gap, which creates a closed coolant envelope around the tool, reducing centrifugal dispersal and ensuring efficient coolant delivery with minimal volumetric flow rate.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If narrow grooves are used to convey coolant, then the coolant can be directed along the tool, but the coolant jet separates from the tool at high rotation speeds and reliable cooling is not guaranteed
Solution Approach 1:
The receiving opening is divided into multiple longitudinal grooves that are distributed around its inner circumference. These grooves segment the coolant flow into multiple streams that collectively form a closed envelope around the tool, ensuring reliable cooling even at high rotation speeds where individual jets might separate.
Solution Approach 2:
The grooves are designed with specific cross-sectional dimensions where the width is significantly larger than the depth (width/depth ratio between 2:1 and 15:1). This dimensional change creates a flat, wide coolant jet that forms a closed envelope around the tool rather than a narrow stream, preventing separation at high speeds.
2Reliability
If coolant flow rate is increased to ensure cooling, then cooling efficiency improves, but coolant pumps with high pumping capacities are required
Solution Approach 1:
The groove cross-section parameters are optimized with a width/depth ratio between 2:1 and 15:1, creating a flat, wide jet configuration. This parameter change allows the coolant to form a closed envelope around the tool that maintains adhesion at high rotation speeds, achieving effective cooling with lower volumetric flow rates and reducing pump power requirements.
3Ease of manufacture
If narrow grooves with square bottom are used, then coolant emerges as bundled jets, but this is not desirable for reliable cooling
Solution Approach 1:
The groove cross-section is designed with width significantly larger than depth (ratio between 2:1 and 15:1), creating a flat groove bottom rather than a narrow square bottom. This parameter change transforms the coolant jet from a bundled narrow stream into a wide, flat flow that forms a closed envelope around the tool, ensuring reliable cooling while remaining manufacturable.
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 a thin, fanned-out coolant jet that adheres to the tool, reducing atomization and mushrooming, and maintains effective cooling without excessive coolant usage, even at high speeds, while minimizing tool vibrations and maintaining tool length.
Implementation Method 1
even at high rotation speeds when it is subject to centrifugal forces
Implementation Method 2
a thin-filmed, fanned-out coolant jet; it has been observed that fanned-out, thinner coolant jets have a greater tendency to at least partially unite into a closed coolant envelope against the tool shank or tool
Data Source
AI summary
The invention relates to a tool holding device comprising a tool holding body for securing, in a fixed manner, a rotary tool comprising a shaft, provided with a clamping section and a receiving opening for the shall of the tool, a coolant feeding device for pressurized fluid, at least one coolant guiding device for guiding the coolant into a clamped tool shaft. The coolant guiding device is designed as at least one flat groove on an inner side of the receiving opening, joining to the front side on a free end of the tool holding body and directly adjacent to the tool shaft in the surroundings of the tool holding device or a coolant storing chamber and or collecting chamber is provided in the region of the free end of the tool holding body, to which the at least one coolant guiding device joins. The coolant storing chamber and or collecting chamber is connected by means of an annular gap to the surroundings of the tool holder device. The coolant storing chamber and/or collecting chamber and the annular gap are defined at least partially by the work shaft.