Induction Coil Unit with Radially Adjustable Pole Elements
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Solution Overview
Problem
Conventional induction coil units for heating rotationally symmetrical components, such as tool holders, face challenges in uniform heating and adaptability to different components, leading to local overheating and difficulties in shrinking radially projecting tools due to stray magnetic fields and laborious pole element adjustments.
Innovation Solution
An induction coil unit with radially movable pole elements made of soft magnetic material, featuring adjustable end faces with varying radial height, curvature, and width, allowing for localized control of magnetic flux and adaptation to varying component contours, along with a drive mechanism and blocking mechanism to control heating profiles.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If a conventional induction coil surrounds the tool holder coaxially, then the tool holder can be heated, but stray magnetic fields cause local overheating and heating of the tool shaft
Solution Approach 1:
The induction coil is segmented into multiple independent coil sections arranged around the tool holder, each section controlled separately to localize magnetic flux generation and eliminate stray fields that cause uniform heating of the entire assembly
Solution Approach 2:
Magnetic flux is concentrated locally at specific heating zones through strategically positioned coil sections and pole pieces, creating high magnetic field density only where heating is required while leaving other areas unaffected
2Object-affected harmful factors
If a pole disc is used to concentrate magnetic flux, then stray fields are reduced, but uniform heating cannot be achieved and radial tools cannot be shrunk
Solution Approach 1:
The single pole disc is replaced by multiple distributed pole pieces or pole segments positioned around the tool holder, each corresponding to a specific heating zone, enabling localized flux concentration while maintaining overall flux distribution control
Solution Approach 2:
The pole pieces are made radially adjustable to dynamically adapt their position and orientation based on the specific heating requirements and tool holder geometry, enabling both uniform heating and localized shrunk fitting operations
3Device complexity
If pole elements are fixed in position, then the device structure is simple, but adaptability to different component contours is poor
Solution Approach 1:
The pole elements are designed with radial adjustability, allowing them to move between retracted and extended positions and adapt their orientation to match different component contours and heating zone requirements, providing versatility without excessive complexity
Solution Approach 2:
The adjustable pole elements serve multiple functions: concentrating flux for localized heating, distributing flux for uniform heating, and adapting to various component geometries, replacing the need for multiple fixed configurations
4Speed
If the induction coil heats the tool holder quickly, then tool shaft removal is enabled, but the tool shaft jams due to heat conduction
Solution Approach 1:
Heating is localized to specific zones of the tool holder using targeted coil sections and pole pieces, rapidly heating only the sleeve areas that need expansion for tool shaft removal, while minimizing thermal conduction to the tool shaft itself through controlled flux distribution
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
Enables more uniform and adaptable heating of components, reducing the risk of local overheating and improving the ease of tool insertion and removal, while allowing for diverse component shapes and sizes to be heated efficiently.
Implementation Method 1
an induction coil unit for heating a component which is rotationally symmetrical relative to an axis and made of an electrically conductive material
Implementation Method 2
produces an axially running magnetic flux, which heats the tool holder surrounded by said induction coil
Implementation Method 3
cover the and face of the induction coil adjacent to the tool with a pole disc made of soft magnetic material, for example ferrite. The pole disc resting on the tool-side end of the tool holder concentrates the magnetic flux in the tool holder
Implementation Method 4
the sleeve part of the tool holder contained in the receiving opening is heated until the internal diameter of the receiving opening has expanded to such an extent that the tool shaft can be inserted or removed
Data Source
AI summary
The induction coil unit for heating a component which is rotationally symmetrical relative to an axis, includes a plurality of coils arranged about the axis of the tool holder, with pole elements, which are movable radially with respect to the axis, of which pole elements each one consists of includes a stack of pole rods that can be moved relative to one another. A yoke ring connects the pole elements, which, when the coils are excited by alternating current in the tool holder, produce a magnetic flux running in the peripheral direction to inductively heat the tool holder. The pole rods of each pole element can be moved jointly by means of pinion rollers, wherein, however, slide couplings or the like are provided in the drive force transmission path between the individual pole rods so that the pole elements can adapt to different contours of the tool holder.