Apparatus and method for precision gear finishing by controlled deformation
AssigneeThe Penn State Research Foundation
InventorsMaurice F. Amateau, Nagesh Sonti
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Abstract
An apparatus and method are provided for the thermomechanical net shape finishing of precision gear tooth surfaces by controlled deformation into metastable austenitic condition. To this end, an arrangement of a fixed axis through-feed motion of workpiece and moving axes in-feed motion of two opposed rolling dies are utilized. By means of process control methods and architecture for accomplishing precision mechanical motions, thermal and environmental control and timely and automatic transfer of workpiece, high strength and high accuracy gear tooth contact surfaces are produced.
Claims41
Apparatus for net shaping gear teeth of a high performance gear comprising:
- means for heating a workpiece in the form of a near net shaped gear blank having carburized gear teeth surfaces above its critical temperature to obtain an austenitic structure throughout its carburized case;
- first quenching means for cooling the workpiece at a rate greater than the critical cooling rate of its carburized case to a uniform metastable austenitic temperature just above the martensitic transformation temperature;
- opposed die means, each having an outer peripheral profiled surface, for rolling the gear teeth surfaces to a desired outer peripheral profiled shape while holding the temperature of the workpiece in the uniform metastable austenitic temperature range;
- and
- second quenching means for cooling the workpiece through the martensitic range for the carburized gear surfaces to harden the gear surfaces.
Apparatus for net shaping gear teeth of a high performance gear from a workpiece in the form of a near net shaped gear blank having carburized gear teeth surfaces initially heated above its critical temperature to obtain an austenitic structure throughout its carburized case, said apparatus comprising:
- a vessel containing a thermally controlled liquid working medium for maintaining the workpiece at a uniform metastable austenitic temperature just above the martensitic transformation temperature;
- first and second rolling gear dies, each having an outer peripheral profiled surface
- meshingly engageable with the outer peripheral profiled surface of the workpiece;
- a support frame mounting said first and second rolling gear dies for rotation on first and second spaced, generally parallel axes;
- and
- means for supporting the workpiece in said liquid working medium for rotation on a third axis which is generally parallel to and intermediate said first and second axes;
- and
- rotary actuator means for rotating said first and second rolling gear dies on the first and second axes, respectively.
Apparatus for net shaping gear teeth of high performance gears comprising:
- supply means for a plurality of workpieces in the form of net shaped gear blanks having carburized gear teeth surfaces;
- a heating station including:
- heating means for heating each workpiece above its critical temperature to obtain an austenitic structure throughout its carburized case;
- and
- upper actuator means releasably engageable with a workpiece for supporting it and for introducing it to said heating means for a selected time period;
- first transfer means for receiving a workpiece from said supply means and for delivering the workpiece to said upper actuator means;
- a first vessel containing a first thermally controlled liquid working medium for maintaining the workpiece at a uniform metastable austenitic temperature just above the martensitic transformation temperature;
- an ausrolling station in said liquid working medium including:
- opposed die means each having an outer peripheral profiled surface for rolling the gear teeth surfaces to a desired outer peripheral profiled shape
- while holding the temperature of the workpiece in the uniform metastable austenitic temperature range;
- and
- lower actuator means for supporting the workpiece in said liquid working medium and for advancing the workpiece from a retracted position to an operating position whereat the gear teeth surfaces of the workpiece meshingly engage said outer peripheral profiled surface of said opposed die means;
- second transfer means for receiving the workpiece from said upper actuator means after lapse of the selected time period, for moving the workpiece rapidly into said first liquid working medium, and for delivering it to said lower actuator means;
- a second vessel adjacent said first vessel and containing a second thermally controlled liquid working medium for maintaining the workpiece at a uniform temperature in the range of approximately 50.degree. F. to 250.degree. F.;
- and
- third transfer means for receiving the workpiece from said lower actuator means after the gear teeth surfaces emulate the desired outer peripheral profiled shape of said opposed die means and for delivering it to said second vessel for final transformation of the carburized case of the workpiece to martensite.
Apparatus for net shaping gear teeth of a high performance gear from a workpiece in the form of a near net shaped gear blank having carburized gear teeth surfaces heated above its critical temperature to obtain an austenitic structure throughout its carburized case, said apparatus comprising:
- a vessel containing a thermally controlled liquid working medium for maintaining the workpiece at a uniform metastable austenitic
- temperature just above the martensitic transformation temperature;
- at least one rolling gear die having an outer peripheral profiled surface meshingly engageable with the outer peripheral profiled surface of the workpiece;
- a housing mounting said rolling gear die for rotation on a die axis;
- and
- attitude adjustment means having at least two degrees of freedom for selectively adjusting the rolling gear die relative to the workpiece.
Dependencies are inferred from the claim text.