Damped Tool Holder Sleeve for Clamping-Induced Bending Loads
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Solution Overview
Problem
Existing tool holders face issues with clamping-induced circulating bending loads, leading to tool breakage, and previous solutions like damping cavities require complex manufacturing and limited design options, making it difficult to achieve desired damping characteristics and adjustability.
Innovation Solution
The tool holder incorporates micro-free areas with low radial depth as local spring elements that block further deformation, allowing for adjustable damping characteristics and easier production, with open spaces on the sleeve's inner and outer surfaces forming cavities that reduce Cardan effects and enable precise damping control.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If damping cavities are incorporated into the sleeve section to reduce circumferential bending stress, then tool shank breakage is prevented, but manufacturing complexity increases and design options are limited
Solution Approach 1:
The damping cavity is segmented into two independent parts: the first damping cavity portion is formed in the sleeve section, while the second damping cavity portion is formed in the cartridge case section. This segmentation allows each part to be manufactured separately using simpler processes, avoiding the need for complex EDM operations on the entire assembly while still providing the complete damping function to prevent tool shank breakage.
Solution Approach 2:
The sleeve section acts as an intermediary component that provides the first damping cavity portion and serves as a interface between the cartridge case section and the tool shank. By distributing the damping function across multiple components (sleeve and cartridge case), the design achieves the required reliability without concentrating manufacturing complexity in a single difficult-to-produce part.
2Reliability
If damping cavities are machined into the sleeve section from the end face, then cardanic effects are eliminated, but manufacturing effort increases significantly
Solution Approach 1:
The damping cavity is divided such that the first portion is formed in the sleeve section and the second portion is formed in the cartridge case section. This segmentation enables the use of simpler manufacturing methods for each component rather than requiring complex end-face machining of the entire assembly, thereby eliminating cardanic effects while reducing overall manufacturing effort.
Solution Approach 2:
Instead of forming the complete damping cavity from the end face of the sleeve section (which requires complex EDM), the damping function is inverted by forming the first cavity portion in the sleeve and the second cavity portion in the cartridge case section, achieving the same cardanic effect elimination through a more manufacturable approach.
3Reliability
If the damping cavity allows large deflection under high forces, then damping effect is enhanced, but manufacturing accuracy deteriorates
Solution Approach 1:
The damping cavity is segmented into two portions with different characteristics: the first damping cavity portion in the sleeve section provides controlled compliance, while the second damping cavity portion in the cartridge case section provides additional damping capacity. This segmentation allows the system to achieve enhanced overall damping effect while each individual portion maintains manufacturing accuracy within acceptable limits.
Solution Approach 2:
Different portions of the damping cavity are designed with different qualities: the first portion in the sleeve section is designed for precision and controlled deflection, while the second portion in the cartridge case section is designed for enhanced damping capacity. This local differentiation allows the system to achieve both manufacturing accuracy and enhanced damping effect simultaneously.
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 provides a tool holder with customizable damping properties, reducing tool breakage risk by allowing selective damping adjustment and interchangeability, while maintaining structural integrity and ease of production.
Implementation Method 1
micro-free areas with low radial depth as local spring elements that block further deformation
Implementation Method 2
open spaces on the sleeve's inner and outer surfaces forming cavities that reduce Cardan effects and enable precise damping control
Data Source
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AI summary
The invention relates to a tool holder (1) comprising a tool receptacle for frictionally clamping a tool shaft. A sleeve (2) is arranged between the tool shaft and the clamping surface of the tool holder (1), said tool holder (1) applying pressure to the tool shaft via the sleeve, producing the friction fit. At least one of the bearing surfaces (3, 4) of the sleeve (2) is interrupted by open surfaces (5, 6) that are designed and arranged such that they form the damping cavities.