Bearing Ring Induction Quenching Segmentation
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Solution Overview
Problem
Existing methods for producing bearing rings with quench-hardened layers along the entire rolling contact surface face challenges such as high production costs for quenching apparatuses and residual stress concentration, leading to potential quench cracking and reduced durability.
Innovation Solution
A method involving induction quenching with a small induction heating member that rotates along the circumferential direction, cooling the heated region to below the Ms point to form a homogeneous quench-hardened layer, using hypereutectoid steel with specific carbon, silicon, manganese, and chromium content to ensure high hardness and carbide formation, thereby reducing production costs and preventing residual stress.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a large-sized induction heating coil is used to heat an annular region along the rolling contact surface of a large-sized bearing ring, then the entire circumference can be quench-hardened simultaneously, but the production cost for the quenching apparatus increases due to the large coil size and high capacity power source required
Solution Approach 1:
The patent divides the large annular region into multiple smaller heating zones by using multiple small-sized induction heating coils arranged circumferentially, replacing a single large coil. This segmentation allows the use of smaller, more cost-effective coils while still achieving comprehensive coverage of the bearing ring's rolling contact surface through coordinated operation of all coils
Solution Approach 2:
The patent combines the heating actions of multiple small induction coils to achieve the same effect as a single large coil. By synchronizing the operation of multiple coils arranged around the bearing ring, the system achieves homogeneous heating and quench-hardening of the entire circumference without requiring expensive large-sized equipment
2Ease of manufacture
If transfer quenching is used with a small-sized induction heating coil moving along the annular region, then the production cost for the quenching apparatus is reduced, but quench cracking occurs due to overlapping of the quench starting region and quench ending region
Solution Approach 1:
The patent segments the heating and cooling process by assigning each induction coil to heat only its local zone, with corresponding cooling zones positioned separately. This prevents the overlapping of heating and cooling regions that causes re-quenching and quench cracking in transfer quenching methods
Solution Approach 2:
The patent applies preliminary cooling to regions before they are heated by the induction coil. By positioning cooling zones upstream relative to the heating zones in the rotational direction, the method prevents these regions from being reheated and re-quenched, eliminating the cause of quench cracking while maintaining the use of small-sized coils
3Ease of manufacture
If transfer quenching is used, then production cost is reduced, but hardness lowers in regions adjacent to the overlapping regions due to tempering after heating to not more than the A1 point
Solution Approach 1:
The patent segments the bearing ring surface into distinct heating zones and cooling zones, ensuring that each zone receives appropriate treatment. This prevents the temperature fluctuations and partial tempering that occur in transfer quenching, maintaining uniform high hardness across the entire surface
Solution Approach 2:
By applying cooling to regions before heating in the rotational sequence, the patent ensures that no region experiences the temperature profile that leads to tempering. This preliminary cooling action prevents hardness reduction in adjacent regions, maintaining uniform surface hardness throughout the bearing ring
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 enables the formation of a homogeneous quench-hardened layer along the entire rolling contact surface of bearing rings, enhancing durability and abrasion resistance while minimizing production costs and residual stress, thus improving the bearing ring's performance and longevity.
Implementation Method 1
forming an annular heated region heated to a temperature of at least an A1 point on the formed body by relatively rotating an induction heating member arranged to face part of an annular region for becoming a rolling contact surface of the bearing ring in the formed body to induction-heat the formed body along the circumferential direction of the annular region
Implementation Method 2
simultaneously cooling the whole of the heated region to a temperature of at most an Ms point
Data Source
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AI summary
A method for producing a bearing ring of a rolling bearing includes the steps of: preparing a formed body constituted of hypereutectoid steel (S10); forming an annular heated region heated to a temperature of at least an A1 point on the formed body by relatively rotating an induction heating member arranged to face part of an annular region for becoming a rolling contact surface of the bearing ring in the formed body to induction-heat the formed body along the circumferential direction of the annular region (S30); and simultaneously cooling the whole of the heated region to a temperature of not more than an Ms point (S40).