Ntn Corporation

Yuuki Tabuchi

Shintaro Suzuki

Tsuneaki Hiraoka

Provided is a heat treatment apparatus (), including: a conveying device (), which is configured to convey a rod-shaped workpiece (W) at a predetermined velocity along an axial direction of the workpiece (W); and a heating device () including a heating coil () configured to inductively heat the workpiece (W) being conveyed to a quenching temperature, wherein the heating coil () includes a first heating section (A) and a second heating section (B), which are coupled to each other in series along the axial direction of the workpiece (W), and is electrically connected to a single high-frequency power supply (), and wherein a coil pitch (D) of the second heating section (B) arranged relatively on a front side in a conveying direction for the workpiece (W) is larger than a coil pitch (D) of the first heating section (A) arranged relatively on a rear side in the conveying direction.

Heat treatment equipment and heat treatment method

When a rod-shaped workpiece (W) having an outer peripheral surface with a circular cross section is inductively heated to a quenching temperature while being conveyed at a predetermined velocity along an axial direction of the rod-shaped workpiece (W), the rod-shaped workpiece (W) being currently conveyed is heated to a predetermined temperature equal to or lower than the quenching temperature by a first heating coil (A), which is electrically connected to a first high-frequency power supply () and has a constant output. Then, the rod-shaped workpiece (W) being currently conveyed is heated so as to be maintained at the quenching temperature by a second heating coil (B), which is electrically connected to a second high-frequency power supply () and has a constant output.

Heat treatment method of rod-shape workpiece

A workpiece conveyance jig, which is formed of a threaded shaft made of a ceramic, includes an inner member, which is formed of a solid shaft having a constant diameter, and is configured to receive a rotational driving force, and an outer member, which has a hollow shaft-like shape, has a helical protrusion, and is mounted on an outer periphery of the inner member so as to be rotatable integrally with the inner member. The outer member includes a plurality of cylindrical bodies arranged in a row in an axial direction of the workpiece conveyance jig, and has a convex and concave fitting portion formed between two adjacent ones of the plurality of cylindrical bodies, which is configured to engage the two adjacent cylindrical bodies with each other in a direction of rotation of the inner member.

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Shizuoka, Japan

Yuuki Tabuchi