Shrink-Fit Chuck Heating Control Using Coil Inductance Feedback
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing shrink-fit devices for tool shafts in tool holders face issues with overheating due to inadequate temperature control, leading to structural changes and potential cracking, and previous solutions like infrared detectors and contacting sensors are prone to errors from surface color, quality, and cleanliness.
Innovation Solution
A method using the present inductance of the induction coil as a measure for the sleeve part's temperature, adjusting the power supply when the inductance reaches a predetermined value to prevent overheating, combined with a compact design featuring a magnetically conductive and electrically nonconductive casing to shield power semiconductor components and reduce leakage fields.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If inductive heating is used to heat the sleeve part of the tool holder, then the shrink-fitting process is accelerated and becomes more efficient, but the sleeve part may be overheated and unintentionally annealed, causing disadvantageous structural changes
Solution Approach 1:
The patent implements feedback control by continuously monitoring the inductance of the induction coil during heating and using this information to automatically adjust the heating power. The control unit compares the measured inductance with reference values to determine the current heating state and adjusts the power supply accordingly, preventing overheating while maintaining efficient heating speed.
Solution Approach 2:
The patent changes the monitoring parameter from direct temperature measurement (which is imprecise due to surface conditions) to inductance measurement. By measuring the inductance of the induction coil, which changes predictably with temperature, the system achieves precise indirect temperature control without contact with the heated surface, thereby preventing overheating.
2Measurement precision
If infrared detectors are used to measure the temperature of the sleeve part, then temperature monitoring is achieved, but the measurement is distorted by surface color, quality, and cleanliness
Solution Approach 1:
The patent introduces an intermediary measurement approach by measuring the inductance of the induction coil instead of directly measuring the temperature of the sleeve part. The inductance serves as an intermediary parameter that reflects the temperature state without being affected by surface conditions, thereby eliminating the distortion problems of direct infrared temperature measurement.
3Measurement precision
If contacting sensors are used to measure the temperature of the sleeve part, then temperature measurement is achieved, but the precision depends on contact intensity and surface cleanliness
Solution Approach 1:
The patent uses inductance measurement as an intermediary that eliminates the need for direct contact with the sleeve part surface. This non-contact measurement method through the induction coil avoids all issues related to contact intensity and surface cleanliness, providing reliable temperature monitoring without operational complexity.
4Reliability
If the sleeve part is overheated multiple times, then it may be necessary to discard the sleeve part and the entire tool holder, but this increases loss of material and time
Solution Approach 1:
The patent implements beforehand cushioning by establishing a feedback control system that prevents overheating before it occurs. By continuously monitoring inductance and automatically adjusting power, the system creates a safety mechanism that protects the sleeve part from reaching dangerous temperature levels, thereby preventing the need to discard the component.
5Weight of moving object
If a compact design with magnetically conductive casing is used to shield power semiconductor components, then the device becomes more suitable for mobile use, but the device complexity increases
Solution Approach 1:
The patent applies multi-functionality by using the magnetically conductive casing to serve multiple purposes: it shields power semiconductor components from leakage fields, provides structural support for the compact design, and enables mobile portability. This consolidates multiple functions into a single component, reducing overall device complexity despite the added shielding requirement.
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 approach provides precise temperature control, preventing damage to the shrink-fit chuck, accelerating cooling, and enabling a more compact, mobile shrink-fit device with improved safety and efficiency.
Implementation Method 1
an induction coil embodied as an annular or cylindrical coil that encompasses the sleeve part of the tool socket and is acted on by an alternating current, which preferably has a high frequency (and ideally, a frequency of greater than 1 kHz), in order to heat the sleeve part
Implementation Method 2
This has significantly accelerated the shrink-fitting process, has made it more efficient and easy to use
Implementation Method 3
the induction coil has a first casing composed of magnetically conductive and electrically nonconductive material on its outer circumference, for example made of ferrite or of a powdered metal material
Implementation Method 4
the present inductance of the induction coil is measured during the inductive heating and is used as a measure for the heating
Data Source
AI summary
The invention relates to a method for monitoring the temperature of the sleeve part of a tool holder, which sleeve part is inserted into the induction coil of a contraction device, wherein the instantaneous inductance of the induction coil is measured during the inductive heating and the current supply to the induction coil is influenced if the instantaneous inductance approaches, reaches, or exceeds a specified value.