Method of quenching workpiece with hole, assistive tool for use in quenching, and crankshaft
AssigneeHonda Giken Kogyo Kabushiki Kaisha
InventorsKazuo Minemura, Noriyuki Okutsu
Life of this patent
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Abstract
A ferrite core partly covered with ceramics members is loaded into an oil hole defined in a pin, and high-frequency induction hardening is effected on the pin while the ferrite core is being held in position by copper wires. At the same time, a magnetic field is generated from the ferrite core to produce a high-frequency induction hardened layer having progressively spreading skirt regions extending from a position in the vicinity of a center in an axial direction of the oil hole toward openings in ends of the oil hole.
Claims7
A method of hardening a workpiece having a hole, comprising the steps of:
- loading an inductive member covered with an electrically insulating member into a hole defined in a workpiece;
- effecting high-frequency induction hardening on the workpiece while the inductive member is being held in position by a holder member made of an electrically conductive material which is disposed in an opening in an end of the hole;
- simultaneously, during application of said inducting hardening, generating a magnetic field from the inductive member loaded in the hole to produce a treated layer adjacent said hole, wherein a radial distance between an axial line of said hole and a surface of said treated layer progressively increases in an axial direction from a position inside of said hole toward openings in respective ends of the hole;
- and
- quenching said workpiece and said hole by cooling said treated layer to produce a hardened layer.
A method of hardening a crankshaft having a hole, comprising the steps of:
- inserting an inductive member covered with an electrically insulating member into a plurality of oil holes defined in each of at least pins and journals of a crankshaft such that the inductive member is loosely fitted in the oil hole;
- effecting induction hardening on each of at least the pins and the journals while said inductive member is being held in said oil hole by a holder member of an electrically conductive material which engages in an opening of said oil hole, thereby producing a treated layer in said oil hole;
- quenching said workpiece and said hole by cooling said treated layer to produce a hardened layer;
- and
- removing said inductive member, said electrically insulating member, and said holder member from said oil hole.
Dependencies are inferred from the claim text.