Inductive Tool Holder Yoke Reducing Stray Magnetic Fields
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing inductive heating devices for tool holders generate stray magnetic fields that can cause unwanted heating of tool shanks, leading to inefficiencies and potential damage.
Innovation Solution
A yoke arrangement with an induction body made of electrically conductive but magnetically non-conductive material forms a partially closed magnetic circuit around the induction coil, creating an opposing magnetic field that weakens the stray field, combined with a flux concentrator and retaining ring for effective shielding.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If an induction coil is used to heat the sleeve section of a tool holder, then the tool holder can be expanded for tool insertion and removal, but stray magnetic fields are generated that cause unwanted heating of the tool shank
Solution Approach 1:
A yoke arrangement made of magnetically conductive material is introduced as an intermediary between the induction coil and the surrounding environment. This yoke arrangement guides and concentrates the magnetic flux, acting as a mediator that directs the magnetic field primarily toward the sleeve section while preventing stray fields from heating the tool shank.
Solution Approach 2:
The stray magnetic field, which was previously a harmful effect causing unwanted heating, is converted into a beneficial effect by using it to induce currents in the yoke arrangement. This converts the harmful stray field into a controlled magnetic circuit that enhances heating of the sleeve section while reducing external interference.
2Adaptability or versatility
If the induction coil is positioned with radial spacing from the sleeve section to accommodate different tool holder diameters, then versatility is improved, but the magnetic field becomes less concentrated and more stray field is generated
Solution Approach 1:
The yoke arrangement serves as a magnetic intermediary that bridges the radial gap between the induction coil and the sleeve section. It provides a low-reluctance path for magnetic flux, maintaining field concentration despite the radial spacing required for versatility.
Solution Approach 2:
The yoke arrangement with induction body creates a multi-functional system that simultaneously achieves universal compatibility with different tool holder diameters (through radial spacing) and maintains effective magnetic coupling (through the yoke's flux-conducting path).
3Manufacturing precision
If a flux concentrator arrangement is used to direct the magnetic field into the sleeve section, then heating precision is improved, but the complexity of the device increases
Solution Approach 1:
The flux concentrator arrangement is merged with the yoke arrangement and induction body to form an integrated magnetic circuit system. This combination achieves precise field direction and concentration while reducing overall device complexity through functional integration.
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 configuration reduces the magnetic field in the external environment, preventing unwanted heating of tool shanks and enhancing the precision of the inductive heating process while maintaining effective tool holder expansion.
Implementation Method 1
The magnetic field of the induction coil induces induction currents in the electrically conductive, mostly also magnetizable material of the tool holder, which directly heat the sleeve section
Implementation Method 2
A magnetic field is created in this induction body or induction attachment, which is superimposed on the field of the induction coil running in the external environment of the induction coil or the device and thus partially weakens it
Implementation Method 3
the sleeve section is heated, for example, by means of an induction coil surrounding it, so that the tool shank can be inserted into the receiving opening of the sleeve section, which expands under the influence of heat
Implementation Method 4
The magnetic field of the induction coil induces induction currents in the electrically conductive, mostly also magnetizable material of the tool holder, which directly heat the sleeve section
Implementation Method 5
the tool shank can be inserted into the receiving opening of the sleeve section, which expands under the influence of heat, i.e. enlarges
Implementation Method 6
On its end faces and on its outer circumference, the winding of the induction coil is covered with a flux concentrator arrangement made of a magnetizable, i.e. ferromagnetic or ferrimagnetic material whose high magnetic conductivity, based on air, essentially concentrates the magnetic flux on this cover
Data Source
Figure 1~2
Figure 3
AI summary
The device has an induction coil arrangement with an induction coil (6) that is energized with an electrical current. A magnetically and electrically non conductive concentrator body (11) concentrates magnetic flux of the coil at a region of tool sided end of a sleeve section (2). The concentrator body carries an inductive attachment (14) made of an electrical conductive material e.g. copper. A supporting ring is made of heat resistant plastic. The attachment is permeated by a field that runs a part outside the concentrator body such that current is induced in the attachment.