US Pat. No. 9,498,840

WELDING STRUCTURAL PART AND WELDING METHOD OF THE SAME

NETUREN CO., LTD., Tokyo...

1. A spot welded structural part, comprising: steel sheets bonded together at an overlapping portion with a weld zone, the
weld zone comprising a weld nugget and a heat affected zone surrounding the weld nugget, the weld nugget being a solidified
mass melted during spot welding,
wherein the weld zone having a hardness gradient where hardness decreases from a bonded edge toward a center of the weld zone,
and

wherein carbide is dispersed in the weld nugget and the heat affected zone, and a dispersion coefficient of particles expressed
by equation (1) shown below is 0.02 or higher, defining that the particle diameter of the carbide dispersed in the weld nugget
and the heat affected zone as d and the mean spacing of particles as L:

Dispersion coefficient of particles=(Square root of particle diameter)/Mean spacing of particles=(d)1/2/L  (1).

US Pat. No. 9,079,266

WELDING EQUIPMENT FOR METALLIC MATERIALS AND METHOD FOR WELDING METALLIC MATERIALS

NETUREN CO., LTD., Tokyo...

1. Spot-welding equipment for metallic materials, sandwiching metallic materials with a pair of electrodes and heating different
regions of the metallic materials by energization with the pair of electrodes maintained at the same position with respect
to the metallic materials, comprising:
a pair of electrodes having respective tips opposing to each other for sandwiching the metallic materials so as to spot-weld
the metallic materials together;

a spot-welding power source connected to the pair of electrodes for supplying a spot-welding power to the pair of electrodes
to heat and spot-weld a prescribed region of the metallic materials sandwiched by the tips of the pair of electrodes, said
spot-welding power being either AC electric power having a first frequency or DC electric power;

a high-frequency power source connected to the pair of electrodes for supplying AC electric power having a second frequency
to the pair of electrodes to heat a region of the metallic materials different from the prescribed region; and

an energization control unit for independently controlling the spot-welding power source and the high-frequency power source,
wherein the first frequency is lower than the second frequency,
wherein the spot-welding power source and the high-frequency power source are respectively connected to the pair of electrodes
in parallel,

wherein the AC electric power having the first frequency or the DC electric power generated by the spot-welding power source
is set so that during spot-welding, an inside of the prescribed region of the metallic materials is heated by the AC electric
power having the first frequency or the DC electric power,

wherein the AC electric power having the second frequency generated by the high-frequency power source is set so that during
spot-welding, a proximity of the prescribed region of the metallic materials is heated by the AC electric power having the
second frequency,

wherein said heating caused by the spot-welding power source and said heating caused by the high-frequency power source are
independently controlled by the energization control unit,

wherein said prescribed region, the inside of which is heated by the AC electric power having the first frequency or the DC
electric power, is a region defined by projecting contacting area of the opposing tips of the pair of electrodes on the metallic
materials, and

wherein said proximity of the prescribed region, which is heated by the AC electric power having the second frequency, is
a ring-shaped area along a circumference of said prescribed region of the metallic materials.

US Pat. No. 9,273,373

HEATING APPARATUS, HEAT TREATMENT APPARATUS, AND HEATING METHOD

NETUREN CO., LTD., Tokyo...

1. A heating apparatus comprising:
a workpiece support on which a ring-shaped workpiece is placed;
a rotary drive assembly;
a heater configured to heat the workpiece; and
a position detector,
wherein the workpiece support comprises a plurality of rotating rollers arranged in a circumferential direction,
wherein the rotary drive assembly is configured to rotate the plurality of rotating rollers to rotate the workpiece placed
on the workpiece support along a ring shape of the workpiece,

wherein the heater comprises:
a heating coil configured to induction-heat the workpiece on the workpiece support at a heating position; and
an actuator configured to move the heating coil at the heating position relative to the workpiece to adjust a distance between
the workpiece and the heating coil,

wherein the position detector is provided upstream of the heating position it direction of the workpiece to detect a position
of a surface of the workpiece, and

wherein the actuator moves the heating coil based on a detection by the position detector.

US Pat. No. 9,410,320

REINFORCED CONCRETE STRUCTURE

NETUREN CO., LTD., Tokyo...

1. A rebar structure comprising:
a plurality of first longitudinal reinforcing bars forming a first frame member; and
a plurality of second longitudinal reinforcing bars forming a second frame member, the second longitudinal reinforcing bars
intersecting the first longitudinal reinforcing bars in a joint section in which the first frame member and the second frame
member are joined to each other,

wherein each of the first longitudinal reinforcing bars comprises a first bar portion having a yield point or a 0.2% proof
stress defined by JIS G 3112, a second bar portion having a strength higher than a strength of the first bar portion, and
a strength transition portion provided between the first bar portion and the second bar portion and having a strength higher
than the strength of the first bar portion but lower than the strength of the second bar portion, the first bar portion, the
second bar portion and the strength transition portion are formed as a single bar structure,

wherein the second bar portion of each of the first longitudinal reinforcing bars is arranged in the joint section,
wherein a boundary between the first bar portion and the strength transition portion of each of the first longitudinal reinforcing
bars is configured as a design point, the designed point being designed such that, when an external force is applied, the
first longitudinal reinforcing bar yields at the designed point before the first longitudinal reinforcing bar yields at a
root of the first frame member at the joint section,

wherein a boundary between the second bar portion and the strength transition portion of each of the first longitudinal reinforcing
bars is located inside the joint section, and the root of the first frame member is located at the strength transition portion,
and

wherein the strength of the strength transition portion of each of the first longitudinal reinforcing bars at the root of
the first frame member is designed to be equal to or higher than a strength back-calculated from a moment distribution.

US Pat. No. 9,304,108

QUENCHING DEPTH MEASUREMENT METHOD AND QUENCHING DEPTH MEASUREMENT APPARATUS

NETUREN CO., LTD., Tokyo...

1. A quenching depth measurement method of measuring quenching depth in a workpiece, the method including:
magnetizing the workpiece by arranging a magnetizer including an excitation coil near the workpiece;
detecting an induction magnetic field generated by the magnetization by a detection coil to measure an output voltage of the
detection coil; and

determining a thickness of a quench hardened layer of the workpiece based on:
known electromagnetic characteristic information on an unquenched material not subjected to quenching and made of a workpiece
equivalent material;

known electromagnetic characteristic information on a completely quenched material subjected to quenching and made of the
workpiece equivalent material; and

an output voltage value measured by the detection coil,
wherein: the electromagnetic characteristic information includes an estimated output voltage value of the detection coil obtained
by analysis based on a finite element method using initial magnetization curves and electric conductivities of the unquenched
material made of a workplace equivalent material, and initial magnetization and electric conductivities of the completely
quenched material made of a workpiece equivalent material.

US Pat. No. 9,907,118

CURRENT APPLYING APPARATUS, CURRENT APPLYING METHOD AND DIRECT RESISTANCE HEATING APPARATUS

NETUREN CO., LTD., Tokyo...

1. A current applying apparatus comprising:
a pair of electrodes configured to contact a workpiece to apply an electric current to the workpiece; and
a bus bar having a surface arranged to extend along the workpiece,
wherein at least one of the electrodes comprises a moving electrode configured to move relative to the bus bar and the workpiece
such that an electric current flows between the bus bar and the workpiece through the moving electrode, the moving electrode
being connected to the bus bar so as to be movable relative to the bus bar, and the moving electrode being configured to contact
the workpiece so as to be movable relative to the workpiece,

wherein the current applying apparatus further comprises a power feeding roller configured to contact and roll on the surface
of the bus bar and to move together with the moving electrode, and

wherein the power feeding roller comprises an electrically-conductive peripheral surface from which the electric current is
supplied to the moving electrode.

US Pat. No. 9,316,294

RACK BAR AND RACK BAR TEETH FORMING DIE

NETUREN CO., LTD., Tokyo...

1. A rack bar configured to mesh with a pinion gear, the rack bar comprising a shaft portion and a rack toothed portion provided
on the shaft portion,
wherein the rack toothed portion comprises a plurality of rack teeth provided side by side in an axial direction of the shaft
portion to mesh with the pinion gear,

wherein each of the rack teeth comprises a tooth tip portion, contact faces arranged obliquely relative to the axial direction
on both sides of each of the rack teeth and configured to contact the pinion gear, and rounded corner portions between the
tooth tip portion and each of the contact faces, and

wherein a first radius defining a central area of each of the rounded corner portions with respect to a tooth width direction
in a cross section taken along the axial direction of the shaft portion at the central area is larger than a second radius
defining another area of each of the rounded corner portions other than the central area in a cross section taken along the
axial direction of the shaft portion at the other area.

US Pat. No. 9,260,866

REBAR STRUCTURE AND REINFORCED CONCRETE MEMBER

NETUREN CO., LTD., Tokyo...

1. A rebar structure comprising a plurality of column longitudinal bars to be connected to a beam,
wherein each of the column longitudinal bars comprises a first reinforcing bar portion extending along an axial direction
of the column longitudinal bars and a second reinforcing bar portion extending further along the axial direction from an axial
end of the first reinforcing bar portion,

wherein the first reinforcing bar portion of each of the column longitudinal bars has a yield point or a 0.2% proof stress
of a reinforcing bar defined by JIS G 3112,

wherein the second reinforcing bar portion of each of the column longitudinal bars has a yield point or a 0.2% proof stress
larger than the yield point or the 0.2% proof stress of the first reinforcing bar portion of each of the column longitudinal
bars, and

wherein each of the column longitudinal bars is partially quenched to form the second reinforcing bar portion.

US Pat. No. 9,328,815

RACK BAR AND RACK BAR TEETH FORMING DIE

NETUREN CO., LTD., Tokyo...

1. A rack bar configured to mesh with a pinion gear, the rack bar comprising a hollow shaft portion, a rack toothed portion
provided on the hollow shaft portion, and a dummy toothed portion,
wherein the rack toothed portion comprises a plurality of rack teeth configured to mesh with the pinion gear,
wherein the rack teeth are provided side by side in an axial direction of the shaft portion, each of the rack teeth comprising
a contact face arranged obliquely relative to the axial direction to contact the pinion gear,

wherein the dummy toothed portion comprises at least one dummy tooth provided on at least one side of the rack toothed portion
in the axial direction such that the dummy tooth is arranged parallel to and next to the rack teeth,

wherein the dummy tooth is designed such that a whole height of the dummy tooth is smaller than a whole height of each of
the rack teeth, and

wherein cross-sectional shapes of an interior surface of the hollow shaft portion corresponding with a location of the rack
teeth and the at least one dummy tooth on an exterior of the hollow shaft portion are even along the axial direction.

US Pat. No. 9,266,282

CORE METAL FOR RESIN WELDING, COMPOSITE MEMBER AND METHOD OF MANUFACTURING THE SAME

NETUREN CO., LTD., Tokyo...

1. A core metal for fitting into a fitting hole with a smooth internal wall surface of an outer peripheral resin member and
subjected to induction heating to allow the outer peripheral resin member to be welded to the peripheral surface, comprising:
a hollow in a shape of an annular groove formed on at least one of the end faces,
a plurality of streaky protrusions formed in a direction crossing the circumferential direction and arranged in the circumferential
direction, and

smooth portions placed on both ends of the streaky protrusions,
wherein the streaky protrusions are forged protrusions formed by forging,
a gap is formed between the streaky protrusions lying next to each other when fitted into the fitting hole of the outer peripheral
resin member,

the height of the plurality of streaky protrusions is 0.9 mm or lower, and the gap between the streaky protrusions lying next
to each other is 2 mm or smaller, and

the width of the smooth portions of the core metal along the central axis falls within the range from 0.5 to 1 times the maximum
width of the gap between the streaky protrusions lying next to each other.

US Pat. No. 9,534,267

INDUCTION HARDENING APPARATUS, INDUCTION HARDENING METHOD, INDUCTION HEATING COIL, HEAT TREATMENT APPARATUS, AND HEAT TREATMENT METHOD

Neturen Co., Ltd., Tokyo...

1. An induction hardening apparatus, comprising:
heating coils disposed around a treatment object having a peripheral surface as a treatment target portion;
the treatment object and the heating coils being relatively moved along a circumferential direction of the treatment target
portion of the treatment object based on rotational movement of at least one of the treatment object and each of the heating
coils;

the treatment target portion of the treatment object being inductively heated;
a stepped peripheral surface with a concave portion aligned along a circumferential direction and a convex portion aligned
along a circumferential direction of the treatment object being determined as the treatment target portion; and

the heating coils comprising:
a first heating coil which is arranged to face a peripheral surface region of the concave portion of the treatment object
and is configured to inductively heat the concave portion of the treatment object; and

a second heating coil which is arranged to face a peripheral surface region of the convex portion of the treatment object
and is configured to inductively heat the convex portion of the treatment object;

at least one of the heating coils comprising a heating conductor portion having a zigzag shape in which a bent portion that
is aligned along a circumferential direction of the rotation and is opened to one side in an axial direction of the rotation
and a bent portion that is arranged along a circumferential direction of the rotation and is opened to the other side in the
axial direction are alternately continuously arranged side by side along the circumferential direction, wherein the first
heating coil and the second heating coil are spaced from each other and adjacently arranged in the circumferential direction
of the treatment object.

US Pat. No. 9,046,157

MANDREL, SET OF MANDRELS, AND HOLLOW RACK BAR

NETUREN CO., LTD., Tokyo...

1. A hollow rack bar formed by pressing a mandrel into a cavity of a hollow material retained in a die and overhanging a wall
of the hollow material from an inner diameter side toward the die, comprising:
a shaft portion having a hollow shape;
a rack tooth forming portion mounted to the shaft portion and having a plurality of tooth portions engaged with a pinion gear
and mounted along an axial direction of the shaft portion in parallel; and

a rear surface portion mounted opposing the rack tooth forming portion of the shaft portion and provided with a circumferential
surface sliding with a guide member for guiding the shaft portion from an outer peripheral side,

wherein in an inner surface side of the rack tooth forming portion of the shaft portion, a center portion is provided with
a convex portion that extends in a direction orthogonal to the axial direction of the shaft portion.

US Pat. No. 9,540,815

REBAR STRUCTURE AND REINFORCED CONCRETE MEMBER

NETUREN CO., LTD., Tokyo...

1. A rebar structure comprising:
a plurality of longitudinal bars extending in an axial direction; a plurality of shear reinforcing bars arranged to surround
the longitudinal bars in a rectangular form in a plane intersecting the axial direction of the longitudinal bars; and

a plurality of bond reinforcing bars arranged adjacent to the shear reinforcing bars in the axial direction of the longitudinal
bars,

wherein the plurality of longitudinal bars includes a first longitudinal bar, a second longitudinal bar, a third longitudinal
bar and a fourth longitudinal bar that are arranged clockwise at least at four corners of the shear reinforcing bars, a fifth
longitudinal bar provided between the first longitudinal bar and the second longitudinal bar and adjacent to the first longitudinal
bar, a sixth longitudinal bar provided between the first longitudinal bar and the second longitudinal bar and adjacent to
the second longitudinal bar, a seventh longitudinal bar provided between the third longitudinal bar and the fourth longitudinal
bar and adjacent to the third longitudinal bar, and an eighth longitudinal bar provided between the third longitudinal bar
and the fourth longitudinal bar and adjacent to the fourth longitudinal bar,

wherein the plurality of bond reinforcing bars includes a first bond reinforcing bar provided around at least a portion of
an outer periphery of the first longitudinal bar and a portion of an outer periphery of the fourth longitudinal bar and having
an inner periphery facing the fifth longitudinal bar and the eighth longitudinal bar, and

wherein the first bond reinforcing bar comprises a U-shaped portion, the U-shaped portion comprising a back section extending
in a direction perpendicular to the axial direction of the longitudinal bars, a first bent section bent from a first end of
the back section and a second bent section bent from a second end of the back section, the first longitudinal bar being arranged
at the first bent section and the fourth longitudinal bar being arranged at the second bent section.

US Pat. No. 9,856,965

METAL CORE FOR RESIN GEAR AND RESIN GEAR COMPOSITE MEMBER

NETUREN CO., LTD., Tokyo...

1. A metal core for a resin gear, the metal core comprising:
a boss portion into which a shaft is press-fitted;
a ring portion having an outer circumferential surface provided with a concave-convex structure and to which an outer peripheral
resin is joined; and

a connecting portion via which the boss portion and the ring portion are coaxially provided,
wherein the boss portion is arranged on one side of the connecting portion at an inner circumference of the connecting portion
and extends annularly in an axial direction,

wherein the ring portion is arranged on the same side of the connecting portion at an outer circumference of the connecting
portion and extends annularly in the axial direction,

wherein the boss portion, the connecting portion, and the ring portion are formed of an integrally continuous material,
wherein the metal core is made of a metal plate and the boss portion is thicker than the connecting portion and the ring portion,
and

wherein the outer circumferential surface of the ring portion includes a smooth section on each of opposite sides of the concave-convex
structure in the axial direction, the smooth sections having a same diameter.

US Pat. No. 9,562,355

REBAR STRUCTURE AND REINFORCED CONCRETE MEMBER

NETUREN CO., LTD., Tokyo...

1. A rebar structure comprising a column and a beam that are connected together, the column comprising a plurality of column
longitudinal bars arranged to extend in a vertical direction and a plurality of column shear reinforcing bars arranged to
surround the column longitudinal bars in a plane intersecting an axial direction of the column longitudinal bars, and the
beam comprising a plurality of beam longitudinal bars arranged to extend in a horizontal direction,
wherein, in a beam-column connecting portion where the column and the beam are connected together, a reinforcing member having
a closed form is provided to surround and to restrain the column longitudinal bars, and

a width of the reinforcing member in the axial direction of the column longitudinal bars is larger than a width of the column
shear reinforcing bars in the axial direction of the column longitudinal bars, and the reinforcing member is spaced in the
vertical direction away from an upper end of the beam-column connecting portion and spaced in the vertical direction away
from a lower end of the beam-column connecting portion, and

wherein the plurality of column shear reinforcing bars includes a first column shear reinforcing bar and a second column shear
reinforcing bar, the first column shear reinforcing bar being provided between the upper end of the beam-column connecting
portion and the reinforcing member, and spaced in the vertical direction away from the upper end of the beam-column connecting
portion and spaced in the vertical direction away from the reinforcing member, and the second column shear reinforcing bar
being provided between the lower end of the beam-column connecting portion and the reinforcing member, and spaced in the vertical
direction away from the lower end of the beam-column connecting portion and spaced in the vertical direction away from the
reinforcing member.

US Pat. No. 9,991,410

METHOD AND APPARATUS FOR MANUFACTURING LEAD WIRE FOR SOLAR CELL

NETUREN CO., LTD., Tokyo...

1. An apparatus for manufacturing a lead wire for a solar cell, the apparatus comprising:a plating bath configured to contain a molten plating solution;
a conveyor mechanism configured to convey a wire material along a conveying path, the conveyor mechanism comprising a turning conveyor roll disposed inside the plating bath, a feeding conveyor roll disposed upstream of the plating bath, and a pulling-up conveyor roll disposed downstream of the plating bath;
a heater configured to heat, by a direct resistance heating or by an induction heating, a portion of the wire material that is being conveyed by the conveyor mechanism between the feeding conveyor roll and the turning conveyor roll; and
a controller configured to control the conveyor mechanism and the heater,
wherein the controller controls a conveying speed of the wire material by the conveyor mechanism and an amount of power supply to the heater such that the wire material is heated to reduce a 0.2% proof stress of the wire material while conveying the wire material and such that the wire material, that is in a heated condition obtained by the direct resistance heating or by the induction heating, is dipped and plated in the plating solution while further conveying the wire material, and
wherein the plating bath and the heater are arranged such that the wire material is plated directly after being heated by the heater.

US Pat. No. 10,314,118

INDUCTION HEATING COIL AND INDUCTION HEATING METHOD

NETUREN CO., LTD., Tokyo...

1. An induction heating coil configured to heat a workpiece having a recess portion provided along a longitudinal axis of the workpiece, the induction heating coil comprising a conductor configured to surround the workpiece around the axis of the workpiece, wherein the conductor comprises a protruding portion protruding inwardly to face the recess portion of the workpiece,wherein the conductor has a size that allows the conductor to surround the workpiece in a state in which the protruding portion is not placed in the recess portion of the workpiece.

US Pat. No. 9,920,826

HOLLOW RACK BAR AND METHOD OF MANUFACTURING HOLLOW RACK BAR

NETUREN CO., LTD., Tokyo...

1. A hollow rack bar comprising:
a hollow blank pipe portion having a uniform wall thickness; and
a rack toothed portion comprising teeth, a flat portion having a flat surface and arranged side by side with the teeth in
a direction along a center axis of the blank pipe portion, and a slanted portion provided at an end of the flat portion with
respect to a direction perpendicular to the center axis and arranged to be lower than the flat portion,

wherein a length of the slanted portion projected on a straight line perpendicular to the center axis and parallel to the
surface of the flat portion is longer than zero and equal to or shorter than the wall thickness of the blank pipe portion
and wherein an angle formed by a plane extended from and parallel to the surface of the flat portion and a surface of the
slanted portion is decreased along the center axis from both sides of a range in which the teeth are provided toward a middle
of the range, and is zero at the middle of the range.

US Pat. No. 10,057,945

INDUCTION HEATING DEVICE, INDUCTION HEATING EQUIPMENT, INDUCTION HEATING METHOD, AND HEAT TREATMENT METHOD

NETUREN CO., LTD., Tokyo...

1. An induction heating device for induction-heating a workpiece on which areas to be heated are established extending in one direction comprising:heating coils facing a portion of the areas to be heated which are established on a part of a surface of the workpiece; and
a relative transfer means for transferring the workpiece and the heating coils along the direction in a relative manner,
wherein when the areas to be heated are induction-heated, the side of one edge and the side of the other edge of the areas to be heated exhibit different deformation amounts in a width direction of the areas to be heated,
wherein the heating coils are disposed so as to correspond to the areas to be heated during heating period,
wherein, the heating coils are disposed facing the areas to be heated while a specified gap is maintained during the heating period, thereby the areas to be heated are heated uniformly across the entire width, and
wherein the heating coils are arranged over the entire length of the areas to be heated uniformly at given intervals from each other.

US Pat. No. 9,926,616

HEATING APPARATUS, HEAT TREATMENT APPARATUS, AND HEATING METHOD

NETUREN CO., LTD., Tokyo...

1. A heating method comprising:placing a ring-shaped workpiece on a plurality of rotating rollers arranged in a circumferential direction;
setting the workpiece at a heating position to face a heating coil;
detecting a position of a surface of the workpiece at a location upstream of the heating position in a rotating direction of the workpiece;
moving the heating coil to adjust a position of the heating coil relative to the workpiece based on the detected position of the surface of the workpiece;
rotating the rotating rollers to rotate the workpiece along a ring shape of the workpiece; and
induction-heating the workpiece.

US Pat. No. 10,138,531

INDUCTION HARDENING CONTROL SYSTEM

NETUREN CO., LTD., Tokyo...

1. An induction hardening control system that is connected to an induction hardening apparatus configured so that a high-frequency inverter is connected to a capacitor and a heating coil and that controls an induction hardening to a work placed in the vicinity of the heating coil, comprising:a hardening control unit that controls the induction hardening apparatus based on setup conditions data regarding the induction hardening apparatus;
a hardening monitoring unit that measures, as measurement data, an electric quantity in an electric circuit configured to include the high-frequency inverter, the capacitor, and the heating coil to monitor an induction hardening status; and
a data collecting unit that collects data from various sensors in the induction hardening apparatus obtained when the work is subjected to the induction hardening by the induction hardening apparatus based on the setup conditions data outputted from the hardening control unit and that collects the measurement data from the hardening monitoring unit to store the data collected from the various sensors and the measurement data so that the data collected from the various sensors and the measurement data are associated to each other,
wherein the induction hardening apparatus has a current transformer which has a primary coil and a secondary coil, the primary coil being connected to the high frequency inverter via the capacitor, the secondary coil being connected to the heating coil,
wherein the hardening monitoring unit measures an output current from the high-frequency inverter or a voltage at the heating coil as the measurement data, the output current measured by a current sensor electrically connected to a wire between the high-frequency inverter and the capacitor, the voltage measured by a voltage sensor connected to the heating coil,
wherein the hardening monitoring unit further comprises a signal processing unit that rectifies the output current and the voltage to calculate a first effective value and a second effective value and removes noises by filters and a determination unit that determines whether the calculated first effective value and the calculated second effective value are within predetermined threshold values, and
wherein the setup conditions data is data for setting an output intensity and an output time from the high-frequency inverter in the induction hardening apparatus.

US Pat. No. 10,189,112

WELDING EQUIPMENT FOR METALLIC MATERIALS AND METHOD FOR WELDING METALLIC MATERIALS

NETUREN CO., LTD., Tokyo...

1. A method for spot-welding metallic materials by sandwiching the metallic materials with respective tips of a pair of electrodes opposing to each other and energizing the metallic materials, wherein:a spot-welding power source is connected to the pair of electrodes for supplying a spot-welding power to the pair of electrodes to heat and spot-weld a prescribed region of the metallic materials sandwiched by the tips of the pair of electrodes, the spot-welding power being either AC electric power having a first frequency or DC electric power, and
a high-frequency power source is connected to the pair of electrodes for supplying AC electric power having a second frequency to the pair of electrodes to heat a region of the metallic materials different from the prescribed region,
the method comprising:
a first step for heating and spot-welding the prescribed region of the metallic materials sandwiched by the tips of the pair of electrodes by a first energization applying, via said spot-welding power source, the AC electric power having the first frequency or the DC electric power to the pair of electrodes; and
a second step for heating said region different from the prescribed region in the first step by a second energization applying, via the high-frequency power source, the AC electric power having the second frequency to the pair of electrodes that are maintained at the same position as in the first step,
wherein the spot-welding power source and the high-frequency power source are respectively connected to the pair of electrodes in parallel,
wherein the first frequency is lower than the second frequency, and
wherein the heating time in the first step and that in the second step are independently controlled.

US Pat. No. 10,154,547

CORE METAL FOR RESIN WELDING, COMPOSITE MEMBER AND METHOD OF MANUFACTURING THE SAME

NETUREN CO., LTD., Tokyo...

1. A method of manufacturing a composite member by fitting a core metal into a fitting hole of an outer peripheral resin member and subjecting them to induction heating, thereby welding the outer peripheral resin member to the peripheral surface of the core metal, comprising:preparing the core metal wherein a plurality of streaky protrusions formed in a direction crossing the circumferential direction and arranged in the circumferential direction and smooth portions placed on both ends of the streaky protrusions are provided on the peripheral surface, said streaky protrusions each having a cross-sectional shape of a mound having a narrower top part and a wider base, with gaps between the mounds of streaky protrusions crossing the circumferential direction;
preparing the outer peripheral resin member wherein the fitting hole is provided with a smooth internal wall surface;
allowing the top parts of the plurality of protrusions to contact, and the smooth portions of the core metal to be separated from and face oppositely, the smooth internal wall surface by fitting the fitting hole of the outer peripheral resin member to the peripheral surface of the core metal; and then
performing induction heating to weld the outer peripheral resin member to the plurality of streaky protrusions and to the smooth portions including heating the core metal to a temperature above a melting temperature of the outer peripheral resin member and melting resin of the outer peripheral resin member to extend into the gaps between the mounds of the streaky protrusions and to extend to the smooth portions.

US Pat. No. 10,060,518

RACK BAR AND RACK BAR TEETH FORMING DIE

NETUREN CO., LTD., Tokyo...

1. A teeth forming die configured to form rack teeth of a rack bar to be meshed with a pinion gear, the teeth forming die comprising a securing portion configured to be secured to an outside clamp case, and a rack teeth transfer portion provided on the securing portion,wherein the rack teeth transfer portion comprises a plurality of rack tooth transfer portions provided side by side in a line,
wherein each of the rack tooth transfer portions is configured to transfer a profile of each rack tooth, each of the rack tooth transfer portions comprising a tooth bottom transfer portion configured to transfer a profile of a tooth bottom portion of the rack tooth, a tooth tip transfer portion configured to transfer a profile of a tooth tip portion of the rack tooth, a contact face transfer portion arranged obliquely relative to a direction of the line in which the rack tooth transfer portions are provided side by side and configured to transfer a profile of a contact face of the rack tooth to be brought into contact with the pinion gear, and a rounded corner portion between the tooth tip transfer portion and the contact face transfer portion,
wherein a first radius defining a central area of the rounded corner portion with respect to a tooth width direction is larger than a second radius defining another area of the rounded corner portion other than the central area.

US Pat. No. 10,301,692

WELDING METHOD AND WELD STRUCTURE

NETUREN CO., LTD., Tokyo...

1. A welding method comprising:forming a spot welding zone provided with a weld nugget formed by conducting spot welding on heat-treated steel sheets in a stack, by applying a pair of electrodes on opposite sides of the steel sheets in the stack at the welding zone;
after forming the spot welding zone, cooling the spot welding zone for a cooling period of 0.4 seconds to 1.0 second while the pair of electrodes are applied at the spot-welding zone; and
after the cooling period, tempering treating the spot welding zone by applying a high-frequency electrical current for a period of 0.3 seconds to 1.0 second across the pair of electrodes while holding the steel sheets under pressure,
forming a hardness at the weld nugget of 150% or less of a hardness of the heat-treated steel sheets; and
at the same time, forming a hardness at a heat affected zone surrounding the weld nugget being 30% to 90% of a hardness at the weld nugget before the tempering treatment by the high-frequency electrical current application.

US Pat. No. 10,285,221

INDUCTION HEATING COIL, INDUCTION HEATING DEVICE, AND HEATING METHOD

NETUREN CO., LTD., Tokyo...

1. An induction heating coil comprising:a primary coil to which electric power is supplied; and
a ring-shaped secondary coil forming a closed circuit,
wherein the primary coil comprises a base-side portion that covers an outer periphery of the secondary coil and a distal-side portion extending from the base-side portion in a center axis direction of the secondary coil in a state in which the base-side portion covers the secondary coil, and an opening width of the base-side portion is greater than an opening width of the distal-side portion,
wherein the secondary coil is provided such that the secondary coil is removable inserted into the primary coil from the base-side portion of the primary coil, and
wherein the primary coil and the secondary coil are disposed such that at least part of a workpiece is accommodated between the distal-side portion of the primary coil and the secondary coil.

US Pat. No. 10,271,384

DIRECT RESISTANCE HEATING METHOD

NETUREN CO., LTD., Tokyo...

1. A direct resistance heating method comprising:placing a first electrode and a second electrode on a plate-shaped workpiece such that the first electrode and the second electrode have sufficient length to extend across the workpiece in a direction perpendicular to a center line of a heating target region of the workpiece, the center line connecting a middle portion of one side of the heating target region and a middle portion of the other side of the heating target region, and the center line being not perpendicular to both the one side and the other side of the heating target region; and
moving at least one of the first electrode and the second electrode along the center line while applying electric current between the first electrode and the second electrode,
wherein said placing comprises (i) placing the first electrode and the second electrode on the plate-shaped workpiece such that the first electrode and the second electrode extend in a direction parallel to both the one side and the other side of the heating target region, and (ii) rotating the workpiece with respect to each of the first electrode and the second electrode such that the first electrode and the second electrode extend in the direction perpendicular to the center line of the heating target region.

US Pat. No. 10,259,028

DIRECT RESISTANCE HEATING METHOD AND PRESS-MOLDED PRODUCT MANUFACTURING METHOD

NETUREN CO., LTD., Tokyo...

1. A direct resistance heating method in which a current is applied to a plate workpiece, a cross-sectional area of which varying in a longitudinal direction of the plate workpiece, and the plate workpiece is heated such that a high-temperature heating region and a non-high-temperature heating region are provided side by side along the longitudinal direction, the direct resistance heating method comprising:a preparation step of arranging a pair of electrodes including a first electrode and a second electrode on the plate workpiece; and
a heating step of moving the first electrode in the longitudinal direction from one end of the high-temperature heating region while applying a current to the pair of electrodes, stopping the movement of the first electrode when the first electrode reaches the other end of the high-temperature heating region, and stopping the current from being applied to the pair of electrodes when a predetermined time elapses after the stopping of the movement of the first electrode.

US Pat. No. 10,462,854

APPARATUS AND METHOD FOR HEATING ANNULAR WORKPIECE, AND HEATING COIL

NETUREN CO., LTD., Tokyo...

1. A heating apparatus for an annular workpiece having a first rim, a second rim and a bottom portion between the first rim and the second rim that are provided continuously in a circumferential direction, the heating apparatus comprising heating coils to be opposed to a portion of the annular workpiece, the heating coils and the annular workpiece being movable relative to each other in the circumferential direction to heat a recessed surface of the annular workpiece by induction heating, the recessed surface being formed by the first rim, the second rim and the bottom portion,wherein the heating coils comprise:
a first heating coil comprising a first corner conductor portion opposed to a first corner portion between the first rim and the bottom portion, and a first bottom conductor portion connected to the first corner conductor portion so as to be opposed to the bottom portion; and
a second heating coil comprising a second corner conductor portion opposed to a second corner portion between the second rim and the bottom portion, and a second bottom conductor portion connected to the second corner conductor portion to be opposed to the bottom portion,
wherein the first bottom conductor portion comprises a first bottom longitudinal conductor portion extending in the circumferential direction, the first corner conductor portion being longer than the first bottom longitudinal conductor portion, and
the second bottom conductor portion comprises a second bottom longitudinal conductor portion extending in the circumferential direction, the second corner conductor portion being longer than the second bottom longitudinal conductor portion.

US Pat. No. 10,470,248

DIRECT RESISTANCE HEATING METHOD

NETUREN CO., LTD., Tokyo...

1. A direct resistance heating method comprising:placing a first electrode and a second electrode such that a space is provided between the first electrode and the second electrode and such that each of the first electrode and the second electrode extends across a heating target region of a workpiece; and
moving at least one of the first electrode and the second electrode with an electric current being applied between the first electrode and the second electrode and with the first electrode and the second electrode contacting the workpiece,
wherein said moving comprises adjusting a period of time during which the electric current is applied for each segment region of the heating target region by adjusting a moving speed of the at least one of the first electrode and the second electrode, wherein the segment regions are defined by dividing the heating target region and are arranged side by side along a direction in which the at least one of the first electrode and the second electrode is moved, and
wherein the at least one of the first electrode and the second electrode is moved in the direction along which a resistance per unit length of the workpiece increases, and the moving speed of the at least one of the first electrode and the second electrode is adjusted in accordance with the increase of the resistance.

US Pat. No. 10,443,108

JIG AND HEATING APPARATUS WITH A JIG

NETUREN CO., LTD., Tokyo...

1. A jig of a heating apparatus, the jig being configured to support a ring-shaped workpiece when conveying and heating the workpiece, the jig comprising:a central structure unit;
a rotary drive mechanism accommodated in the central structure unit; and
a workpiece support connected to the central structure unit and configured such that the workpiece is placed on the workpiece support to surround the central structure unit,
wherein the workpiece support comprises a plurality of rotating rollers arranged in a circumferential direction around the central structure unit,
wherein the central structure unit comprises:
a conveyor connecting portion configured to suspend the workpiece support together with the workpiece placed on the workpiece support; and
a driver connecting portion from which a driving force is input to the rotary drive mechanism, and
wherein the rotary drive mechanism is configured to rotate the rotating rollers by the driving force to rotate the workpiece along a ring shape of the workpiece.

US Pat. No. 10,415,109

WORKPIECE FOR INDUCTION HARDENING

NETUREN CO., LTD., Tokyo...

1. A workpiece for an induction hardening, the workpiece comprising a first inclined surface, a second inclined surface, and a connecting surface connecting the first inclined surface and the second inclined surface on a side toward which the first inclined surface and the second inclined surface approach each other, wherein the connecting surface comprises a recessed portion.

US Pat. No. 10,415,114

WIRE HEATING SYSTEM AND WIRE HEATING METHOD

NETUREN CO., LTD., Tokyo...

1. A wire heating system comprising:an induction heating apparatus comprising a power supply and an induction coil arranged to heat a wire rod by an induction heating using current supplied from the power supply; and
a controller configured to control the current to be supplied to the induction coil based on a feeding speed of the wire rod,
wherein the induction heating apparatus has a heating section in which the wire rod is heated by the induction heating using the induction coil, and a soaking section disposed downstream of the heating section to homogenize the temperature distribution of the wire rod induction-heated by the induction coil such that the temperature of the wire rod at a downstream end of the soaking section becomes a target temperature,
wherein the controller is configured to control the current to be supplied to the induction coil such that the temperature of the wire rod at the downstream end of the soaking section becomes the target temperature,
wherein the feeding speed has an increasing state and a decreasing state, and
wherein the controller is configured to control the current to be supplied to the induction coil so as to satisfy I=k×v0.5+?I, wherein I is the current to be supplied to the induction coil, v is the feeding speed of the wire rod, k is a proportional constant, and ?I is a standby current.

US Pat. No. 10,458,775

HARDENED LAYER DEPTH MEASURING APPARATUS

NETUREN CO., LTD., Tokyo...

1. A hardened layer depth measuring apparatus configured to measure a depth of a hardened layer formed at a surface layer of a quenched workpiece, the hardened layer depth measuring apparatus comprising:an exciting coil configured to generate a magnetic flux to magnetize the workpiece responsive to an alternating excitation current output by a power supply;
a detecting coil configured to detect the magnetic flux generated by the exciting coil; and
a processor,
wherein the exciting coil comprises a U-shaped excitation core portion and an excitation coil portion wound on the excitation core portion, the excitation core portion being arranged such that distal ends of magnetic poles of the excitation core portion face the workpiece, and
wherein the detecting coil comprises a detection core portion having layers of magnetic sheets and a detection coil wound on the detection core portion, the detection core portion being arranged between the magnetic poles of the excitation core portion and along a surface of the workpiece,
wherein the detection core portion is connected to the processor, the processor being configured to calculate the depth of the hardened layer based on a detection voltage output from the detection core portion and a predetermined correlation between hardened layer depth values and detection voltage values, and
wherein a current value and a frequency value of the excitation current are selected such that the detection voltage is approximately proportional to the depth of the hardened layer.

US Pat. No. 10,449,995

HOLLOW RACK BAR AND METHOD OF MANUFACTURING THE HOLLOW RACK BAR

NETUREN CO., LTD., Tokyo...

1. A method of manufacturing a hollow rack bar, having a rack portion configured to be engaged with a pinion gear and supported faces provided on a back side of a rack teeth portion and configured to be supported by a yoke, the method comprising:forming the rack portion by locating a toothed mold on an outer face of a circular tube material, and inserting a cored bar into the circular tube material to pressurize an inner face of the circular tube material, thereby transferring a shape of the toothed mold, and then
forming the supported faces by removal processing or deforming processing of the back side of the rack teeth portion of the circular tube material.