Coil Spring Manufacturing via Induction Heating and Helicoid Reduction
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Solution Overview
Problem
Conventional coil spring manufacturing methods require multiple materials for varying diameters, are environmentally unfriendly due to fossil fuel use, and result in decreased quality and increased production costs, especially when aiming for lightweight, high-stress coils.
Innovation Solution
A method using a helicoid reduction mill to hot-roll and form coil springs within seconds, maintaining austenite structure, densifying metal texture, and adjusting diameters to produce high-stress coils with increased fatigue life and reduced weight, while eliminating the need for multiple materials and fossil fuels by using induction heaters.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by stationary object
If conventional hot coil spring manufacturing method is used with heating furnace, then coil spring material can be heated to required temperature, but fossil fuels are consumed and environment-friendly manufacturing cannot be achieved
Solution Approach 1:
The patent replaces the conventional heating furnace (thermal system) with an induction heating system that uses electromagnetic fields to directly heat the coil spring material. This substitution eliminates the need for fossil fuels and external combustion, achieving environment-friendly manufacturing while maintaining the required heating temperature of 950-1000°C
Solution Approach 2:
The patent changes the heating method from indirect furnace heating to direct induction heating, altering the physical parameter of heat transfer mechanism. This enables precise temperature control and eliminates harmful emissions while achieving the same thermal effect required for coil spring formation
2Temperature
If coil spring material is heated in heating furnace for extended period, then required temperature can be achieved, but decarbonization and oxide film formation occur on surface reducing coil spring quality
Solution Approach 1:
The induction heating system replaces the heating furnace, enabling rapid and uniform heating throughout the coil spring material simultaneously. This eliminates the gradual heating process that causes prolonged exposure to oxidizing atmosphere, preventing surface decarbonization and oxide film formation while achieving the required 950-1000°C temperature
Solution Approach 2:
The induction heating process rapidly heats the coil spring material through electromagnetic induction, skipping the prolonged heating stage that causes surface degradation. The material reaches the required temperature quickly and uniformly, minimizing exposure time to conditions that cause decarbonization and oxidation
3Adaptability or versatility
If multiple coil spring materials with different diameters are prepared for various material diameters, then coil springs of various sizes can be manufactured, but production complexity and material inventory requirements increase
Solution Approach 1:
The patent makes a single coil spring material serve multiple functions by enabling it to be formed into different diameter specifications through the induction heating and forming process. One universal material can be adapted to produce various coil spring diameters, eliminating the need to maintain separate material inventories for different specifications
Solution Approach 2:
The patent changes the forming parameters (temperature, forming pressure, coil geometry) during the manufacturing process to produce different material diameters from the same starting material. This parameter flexibility allows one material to be transformed into various final dimensions, reducing material preparation complexity
4Strength
If high-stress coil spring materials containing special metals are used to decrease coil spring weight, then tensile strength increases, but production cost increases
Solution Approach 1:
The patent optimizes the heating temperature parameter (950-1000°C) and forming conditions to maximize the strength properties of standard coil spring materials. By precisely controlling these parameters, the material achieves high tensile strength without requiring expensive special metal alloys, thereby reducing production cost while maintaining the desired strength level
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 method produces high-strength, lightweight coil springs with extended fatigue life, reduces material usage, and decreases vehicle weight, enabling lower fuel consumption while maintaining coil spring quality and environmental sustainability.
Implementation Method 1
heating to a predetermined temperature in an induction heater
Implementation Method 2
an austenite structure can be safely maintained at room temperature
Implementation Method 3
densifying the metal texture of a left-twisted or right-twisted coil spring in a stress direction
Implementation Method 4
the tensile strength of the formed spring coil becomes higher due to an ausforming effect occurring at the time of quenching special steel
Data Source
AI summary
A method of manufacturing a coil spring using a helicoid reduction mill includes supplying a coil spring material linearly unrolled by a prestraightener to a surface treatment machine and then short-blasting or scarfing its outer surface to surface-treat the coil spring material; primarily heating the surface-treated coil spring material to a predetermined temperature using a first heater; sequentially supplying and pressurizing the primarily-heated coil spring material in a stepwise fashion such that the coil spring material has the same diameter as that of a coil spring to be manufactured; measuring the diameter and the length of the coil spring material and then cutting the coil spring material to a desired size; secondarily heating the cut coil spring material to a predetermined temperature using a second heater; forming the secondarily heated coil spring material into a coil spring using a coiling machine; and oil-quenching and then tempering the formed coil spring.