Tocco, Inc.

Donald E Novorsky

George D Pfaffmann

George M Mucha

Norbert R Balzer

Michael R Hammond

Robert J Bednarz

A method and apparatus for inductively heating in an inductor and quench hardening the finished ground cam lobes of steel camshafts to a uniform shallow pattern depth with minimal lobe surface deformation. The inductor is shaped to correspond to the contour of and encircle the individual cam lobes with a minimal uniform induction coupling gap therebetween of less than 0.1 inch, and it is energized with high intensity power at a high frequency greater than 200 KHz, with sufficient power to create a power density of at least 25 KW/inch.sup.2 at the surface of the cam lobe being heated in the inductor, for only a short heat time less than 1.0 second so as to effect the rapid inductive heating of the cam lobe surface to a uniform elevated temperature and uniform shallow depth therearound without causing unacceptable reheating and resultant drawing back or tempering of the previously hardened next adjacent cam lobe. The inductor is comprised of two complementary elongated copper segments which are normally interconnected to one end to form a conductor loop and conjointly provide a ring-shaped inductor element of the aforementioned contour for receiving the individual cam lobes in inductive heating position therein. The inductor segments are movable apart laterally outward from the camshaft a sufficient distance to permit both axial and rotative index movement of the camshaft relative to the inductor to position the other cam lobes of the camshaft individually in proper axial and rotative oriented position for encirclement and inductive heating by the inductor.

Method and apparatus for hardening cam lobes on a camshaft

A method and apparatus for induction heating and quench hardening of an undulating cylindrical surface, such as that defined by gear or sprocket teeth, provide a hardness pattern uniformly distributed to a controlled depth across and between the teeth surfaces by means of axial scanning of the workpiece relative to a single induction heating coil. A distinct final heating scanning process follows a preheating scanning process whereby preheating and final heating can be conducted at differing controlled axial velocities. Axial scanning of the workpiece repeatedly past a single inductor coil enables preheating and final heating of workpieces which cannot be axially shifted directly between separate inductor coils, such as internal planetary ring gears having a closed end or external gears having a flange or shoulder protruding radially from the cylindrical gear teeth surface.

Method and apparatus for induction heating of gear teeth

A method and apparatus for inductively heating in an inductor and quench hardening the finished ground cam lobes of steel camshafts to a uniform shallow pattern depth with minimal lobe surface deformation. The inductor is shaped to correspond to the contour of and encircle the individual cam lobes with a minimal uniform induction coupling gap therebetween of less than 0.1 inch, and it is energized with high intensity power at a high frequency greater than 200 KHz, with sufficient power to create a power density of at least 25 KW/inch.sup.2 at the surface of the cam lobe being heated in the inductor, for only a short heat time less than 1.0 second so as to effect the rapid inductive heating of the cam lobe surface to a uniform elevated temperature and uniform shallow depth therearound without causing unacceptable reheating and resultant drawing back or tempering of the previsouly hardened next adjacent cam lobe. The inductor is comprised of two complementary elongated copper segments which are normally interconnected at one end to form a conductor loop and conjointly provide a ring-shaped inductor element of the aforementioned contour for receiving the individual cam lobes in inductive heating position therein. The inductor segments are movable apart laterally outward from the camshaft a sufficient distance to permit both axial and rotative index movement of the camshaft relative to the inductor to position the other cam lobes of the camshaft individually in proper axial and rotative oriented position for encirclement and inductive heating by the inductor.

Method and apparatus for hardening the outwardly facing teeth surfaces of a gear is disclosed. First and second induction heating coils with power sources controlled by an appropriate microprocessor preheat the gear when in the first coil at precisely controlled cycles to generate an unstable circular band of high temperature positioned radially inwardly from the tips of the gear. Before the band can dissipate, the microprocessor actuates an appropriate drive to locate the gear in the second coil energized by an appropriate power source to impart a high skin temperature to the teeth. A liquid spray quench in the second coil is immediately actuated to effectively quench the gear. By sizing the cycles, the gear teeth are rapidly hardened at minimal power levels.

Method and apparatus for hardening gears

A method and apparatus for progressively hardening an elongated workpiece having an outer generally cylindrical surface concentric with the central axis including the concept of providing closely spaced first and second induction heating coils each having workpiece receiving openings generally concentric with the axis of the workpiece; energizing the first coil with a low frequency such as a frequency less than about 50 KHz; energizing the second coil with a high radio frequency, such as the frequency exceeding 100 KHz; causing relatively axial and progressive motion between the workpiece and the first and second closely spaced coils in a direction entering the first coil and exiting the second coil whereby the cylindrical surface is progressively first preheated by the first coil and then immediately final heated by the second coil; and, then immediately quenching the cylindrical surface as it passes from the second coil whereby the cylindrical surface is progressively preheated, heated and quench hardened as the workpiece is moved through the induction heating coil.

Method and apparatus for hardening gears and similar workpieces

An apparatus for hardening the outwardly facing teeth surfaces of a gear is disclosed. First and second induction heating coils with power sources controlled by an appropriate microprocessor heat the gear when in the first coil at a precisely controlled cycle to generate an unstable, circular band of high temperature positioned radially inwardly from the tips of the gear. Before the band can dissipate, the microprocessor actuates an appropriate drive to locate the gear in the second coil energized by an appropriate power source to impart a high skin temperature to the teeth. A liquid spray quench in the second coil is immediately actuated to effectively quench the gear. By sizing the cycles, the apparatus is thus able to rapidly harden the gear teeth at minimal power levels.

System for hardening gears by induction heating

A method and apparatus for inductively heating in an inductor and quench hardening the finished ground cam lobes of steel camshafts to a uniform shallow pattern depth with minimal lobe surface deformation. The inductor is shaped to correspond to the contour of and encircle the individual cam lobes with a minimal uniform induction coupling gap therebetween of less than 0.1 inch, and it is energized with high intensity power at a high frequency greater than 200 KHz, with sufficient power to create a power density of at least 25 KW/inch.sup.2 at the surface of the cam lobe being heated in the inductor, for only a short heat time less than 1.0 second so as to effect the rapid inductive heating of the cam lobe surface to a uniform elevated temperature and uniform shallow depth therearound without causing unacceptable reheating and resultant drawing back or tempering of the previously hardened next adjacent cam lobe. The inductor is comprised of two complementary elongated copper segments which are normally interconnected at one end to form a conductor loop and conjointly provide a ring-shaped inductor element of the aforementioned contour for receiving the individual cam lobes in inductive heating position therein. The inductor segments are movable apart laterally outward from the camshaft a sufficient distance to permit both axial and rotative index movement of the camshaft relative to the inductor to position the other cam lobes of the camshaft individually in proper axial and rotative oriented position for encirclement and inductive heating by the inductor.

Method for hardening cam lobes on a camshaft

A method and apparatus for progressively hardening an elongated workpiece having an outer generally cylindrical surface concentric with the central axis including the concept of providing closely spaced first and second induction heating coils each having workpiece receiving openings generally concentric with the axis of the workpiece; energizing the first coil with a low frequency such as a frequency less than about 50 KHz; energizing the second coil with a high radio frequency, such as the frequency exceeding 100 KHz; causing relatively axial and progessive motion between the workpiece and the first and second closely spaced coils in a direction entering the first coil and exiting the second coil whereby the cylindrical surface is progressively first preheated by the first coil and then immediately final heated by the second coil; and, then immediately quenching the cylindrical surface as it passes from the second coil whereby the cylindrical surface is progressively preheated, heated and quench hardened as the workpiece is moved through the induction heating coil.

Method and apparatus for induction heating gears and similar workpieces

A method and apparatus is disclosed for obtaining an improved bond between two structural members. Spherical particles, preferably graded steel shot, are interspersed within the adhesive and move in sliding and rolling contact relative to one another to establish an accurate space between opposing face surfaces of the structural members as the structural members are brought into pressured contact with one another. An induction coil may then be used to accurately heat the spherical particles and thus establish a heat source to thermally set the adhesive from within the spaced gap between the structural members established by the spherical particles.

Induction heating for adhesive bonding

A method of hardening the radially, outwardly facing surfaces of a generally circular, toothed workpiece adapted to rotate about a central axis generally concentric with the outwardly facing surfaces whereby the extremities of the surfaces define an outer circle by the tips of the teeth of the workpiece. This type of workpiece is generally a gear. The method comprises the steps of providing first and second induction heating coils, locating the workpiece concentric in the first induction heating coil, energizing the first induction heating coil with a first alternating frequency current for a first time period, deenergizing the first coil with the workpiece therein for a first time delay period, again energizing this first induction heating coil with a second alternating frequency current for a second time period substantially less than the first time period, immediately transferring the workpiece concentrically into the second induction heating coil in a second delay time, then energizing the second induction heating coil with a radio frequency current for a third time period and immediately quenching the outer surfaces by quenching liquid sprayed against the surfaces while the workpiece is in the second induction heating coil. This process can be employed for hardening various convoluted surfaces where the area to be hardened, compared to the mass adjacent thereto, is substantially less than the area compared to adjacent mass at the protruding convolution, i.e. generally gear teeth.

Method and apparatus of hardening gears by induction heating

A method and apparatus for shaping, in a planar direction, an elongatd generally flat surface formed in a steel workpiece and having a geometric continuous configuration, such as the outer facing surface of a cam on a camshaft for an internal combustion engine, which involve providing an inductor having a generally continuous heating surface matching the cam surface and generally parallel with the cam surface, forming at least one elongated uniformly cross-section groove in the inductor heating section and extending in a preselected linear location with respect to the heating surface and coterminous with the inductor heating surface, positioning the camshaft with the cam surface facing the parallel matching heating surface of the inductor with an air gap between the parallel matching surfaces so that the groove in the inductor surface faces a preselected band of the cam surface, such as the middle portion of the cam surface, energizing the inductor with a current having a frequency of less than about 25 KHz for a time less than about 3.0 seconds with a power density of about 20-70 KW/in.sup.2, at the cam surface, whereby the steel surface is heated to a temperature above the hardening temperature of the cam surface, with the higher power density at the outer edges of the cam surface, and immediately quench hardening the cam surface with a liquid quenching substance whereby the flatness of the cam surface is controlled by the position of the elongated groove. An equivalent result can be accomplished by other arrangements for changing the heating effect and particular band around the cam surface preparatory to immediate quench hardening.

Method and apparatus for shaping the surfaces of cams on a camshaft

A method of hardening the radially, outwardly facing surfaces of a generally circular, toothed workpiece adapted to rotate about a central axis generally concentric with the outwardly facing surfaces whereby the extremities of the surfaces define an outer circle by the tips of the teeth of the workpiece. This type of workpiece is generally a gear. The method comprises the steps of providing first and second induction heating coil, locating the workpiece concentric in the first induction heating coil, energizing the first induction heating coil with a first alternating frequency current for a first time period, deenergizing the first coil with the workpiece therein for a first time delay period, again energizing this first induction heating coil with a second alternating frequency current for a second time period substantially less than the first time period, immediately transferring the workpiece concentrically into the second induction heating coil in a second delay time, then energizing the second induction heating coil with a radio frequency current for a third time period and immediately quenching the outer surfaces by quenching liquid sprayed against the surfaces while the workpiece is in the second induction heating coil. This process can be employed for hardening various convoluted surfaces where the area to be hardened, compared to the mass adjacent thereto, is substantially less than the area compared to adjacent mass at the protruding convolution, i.e. generally gear teeth.

Method for hardening gears by induction heating

A method and apparatus for the heat treating of quench hardenable ferrous alloy workpieces utilizing periodic eddy current excitation and reflection to determine the in-line cooling rate from the critical temperature of the workpiece material and comparing the in-line cooling rate against a standard rate for establishing acceptance or rejection of the quenched workpiece.

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Pleasant Ridge, MI, United States of America

Donald E Novorsky