Heating Coil Asymmetric Lead Design for Induction Quenching
Solution Overview
Problem
Existing heating coils face inefficiencies in heating circumferentially extending target portions on the inner surface of works, particularly in reducing stress and improving power transmission efficiency, especially when dealing with small diameter components and concave raceway surfaces.
Innovation Solution
A heating coil design featuring linear lead portions with a rectangular cross-section and a ring-shaped or coil-shaped head portion with a circular or elliptical outer surface, where the lead portions have straight side portions that facilitate high electric current concentration and reduced magnetic repulsion, enhancing power transmission efficiency and mechanical strength.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If circular cylindrical lead members are used, then the heating coil can be compact, but electric current density becomes non-uniform and magnetic repulsion increases
Solution Approach 1:
The lead members are designed with an asymmetric cross-sectional shape featuring a straight side and a curved side. The straight sides of adjacent lead members are positioned facing each other, creating a symmetric arrangement of straight portions that concentrates electric current flow efficiently while reducing magnetic repulsion between the lead members.
2Productivity
If larger electric current is supplied to increase quenching amount, then heating efficiency improves, but magnetic repulsion between lead members increases causing unnecessary stress
Solution Approach 1:
The asymmetric cross-sectional shape with straight sides facing each other optimizes current distribution and minimizes magnetic repulsion forces, allowing higher currents to be supplied without excessive stress on the coil structure.
Solution Approach 2:
The cross-sectional geometry parameters of the lead members are optimized to balance current carrying capacity with mechanical stress resistance, enabling efficient power transmission at higher currents.
3Productivity
If rectangular pipe heating conductor is used, then linear heating is efficient, but concave circumferential heating target portions cannot be heated efficiently
Solution Approach 1:
The head portion is designed with a curved outer circumferential surface that can conform to concave heating target portions such as raceway surfaces. This curved geometry enables efficient heat transfer to circumferential features while the linear lead portions maintain effective linear heating capability.
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 achieves efficient heating of circumferentially extending target portions with reduced stress on the heating coil and improved heat distribution, allowing for uniform heating and increased mechanical strength, as demonstrated by reduced power loss and vibration suppression.
Implementation Method 1
a heating coil includes a pair of lead portions connected to a power supply, and a ring-shaped or coil-shaped head portion having end portions connected to the lead portions respectively... efficiently heating a circumferentially extending heating target portion on an inner circumferential surface of a work
Implementation Method 2
A flow path through which a cooling medium flows is formed inside the lead portions and the head portion
Data Source
AI summary
A heating coil includes a pair of linear lead portions adapted to be connected to a power supply, and a ring-shaped or coil-shaped head portion having end portions connected to the lead portions respectively. A flow path through which a cooling medium flows is formed inside the lead portions and the head portion. An outer circumferential surface of the head portion has a circular or elliptical cross section and is configured to face a heating target portion of an inner circumferential surface of a work extending, the heating target portion extending in a circumferential direction of the work. Each of the lead portions has a straight side portion in a plane intersecting a longitudinal direction of the lead portions, the straight side portions of the lead portions being arranged in proximity to each other.