Gear Patents (Class 148/586)
  • Patent number: 9874273
    Abstract: A method for manufacturing a flexible externally toothed gear includes: a first step (ST1) for producing a primary molded article by performing near-net-shape plastic working on a material comprising a nickel-free low-alloy steel having a silicon content of 1.45-1.5 wt %; a second step (ST2) for martempering the primary molded article; a third step (ST3) for producing a secondary molded article from the primary molded article; and a fourth step (ST4) for shot-peening the secondary molded article to change the surface portions of the tooth part and other parts to martensite. A flexible externally toothed gear can be obtained in which the surface hardness is kept within a prescribed range and the fatigue strength and abrasion resistance are high.
    Type: Grant
    Filed: February 2, 2015
    Date of Patent: January 23, 2018
    Assignee: HARMONIC DRIVE SYSTEMS INC.
    Inventors: Masaru Kobayashi, Daisuke Orii
  • Patent number: 8940109
    Abstract: A method for manufacturing a base material for a wave gear which enables the effective suppression of man-hours and manufacturing cost while providing the required strength and elastic deformation characteristics for an external gear of a wave gear. In this manufacturing method, steel having a carbon content of 0.48% or less is subjected to primary molding by being cold worked into the shape of an external gear for a wave gear. The resulting primary molded article is heated to a temperature range in which the main phase of the metallographic structure thereof forms an austenitic structure. The main phase of the metallographic structure is formed into bainite by carrying out quenching to a predetermined temperature higher than the martensitic transformation starting temperature and maintaining the temperature for a predetermined time. The product is then cooled to normal temperature.
    Type: Grant
    Filed: March 14, 2011
    Date of Patent: January 27, 2015
    Assignee: Aisin Seiki Kabushiki Kaisha
    Inventors: Eiri Nagata, Nobuaki Kurita
  • Patent number: 8894778
    Abstract: The present invention relates to a mechanical part, which is obtained by: processing a steel into a shape of a part, the steel having an alloy composition containing, by weight percent, C: 0.10 to 0.30%, Si: 0.50 to 3.00%, Mn: 0.30 to 3.00%, P: 0.030% or less, S: 0.030% or less, Cu: 0.01 to 1.00%, Ni: 0.01 to 3.00%, Cr: 0.20 to 1.00%, Al: 0.20% or less, N: 0.05% or less, and the remainder of Fe and inevitable impurities, and the alloy composition satisfying the following condition: [Si %]+[Ni %]+[Cu %]?[Cr %]>0.50, in which [Si %], [Ni %], [Cu %] and [Cr %] represent the concentration of Si, the concentration of Ni, the concentration of Cu and the concentration of Cr in the alloy composition, respectively; subjecting the steel to a carburizing treatment in a vacuum, followed by gradually cooling the steel; and subsequently subjecting the steel to a high-frequency hardening to thereby harden a surface of the steel.
    Type: Grant
    Filed: April 8, 2008
    Date of Patent: November 25, 2014
    Assignees: Daido Tokushuko Kabushiki Kaisha, Aisin Aw Co., Ltd.
    Inventors: Toshiyuki Morita, Kouji Ohbayashi, Masaki Kuwabara, Taro Matsukawa, Yutaka Eto, Kohki Mizuno
  • Patent number: 8758527
    Abstract: A surface processing method includes the step of increasing a surface hardness of a metal having a nominal composition that includes about 0.21-0.25 wt % carbon, about 2.9-3.3 wt % chromium, about 11-12 wt % nickel, about 13-14 wt % cobalt, about 1.1-1.3 wt % molybdenum, and a balance of iron from a first hardness to a second hardness. For example, the method is used to produce a surface-hardened component that includes a core section having a first hardness between about 51 HRC and 55 HRC and a case section having a second hardness that is greater than the first hardness.
    Type: Grant
    Filed: December 15, 2006
    Date of Patent: June 24, 2014
    Assignee: Sikorsky Aircraft Corporation
    Inventors: Tapas K. Mukherji, Michael E. Dandorph, Bruce D. Hansen, Edward J. Karedes
  • Patent number: 8733199
    Abstract: A method of manufacturing a gear, and the resulting gear, the method resulting such that the surface layer portions of the tooth portions and a tooth root portion are made to be a carburized layer, the remaining portion of the tooth portions and a portion of a disk portion lying below the carburized layer be a quench-hardened layer, and a region of the disk portion lying deeper than the quench-hardened layer be an unquenched layer. The gear is manufactured using raw material steel having the following chemical composition: C: 0.1% to 0.40% (% by mass), Si: 0.35% to 3.0%, Mn: 0.1% to 3.0%, Cr: less than 0.2%, Mo: 0.1% or less, P: 0.03% or less, S: 0.15% or less, Al: 0.05% or less, N: 0.03% or less, and Fe and unavoidable impurities.
    Type: Grant
    Filed: April 8, 2011
    Date of Patent: May 27, 2014
    Assignees: Aisin AW Co., Ltd., Nippon Steel Corporation
    Inventors: Koji Obayashi, Keita Taguchi, Susumu Kato, Shuji Kozawa, Manabu Kubota, Yuji Adachi, Hirokazu Sato
  • Publication number: 20130248058
    Abstract: The present disclosure relates to methods of hardening toothed gear parts for engines. The method results in a uniformly hardened gear with minimized distortion.
    Type: Application
    Filed: March 20, 2012
    Publication date: September 26, 2013
    Applicant: BRUNSWICK CORPORATION
    Inventor: Terrance Cleary
  • Patent number: 8444781
    Abstract: The subject invention discloses a process for strengthening and obtaining the desired dimensions for a metal part comprising: (1) heating at least a portion of a preformed metal part to a temperature above about 1300° F. to transform the metal in at least said portion of the part to an austenitic state to produce an austenitized preformed metal part, (2) quenching the austenitized preformed metal part to a temperature of 300° F. to 650° F. to put the metal in the preformed part in a metastable austenitic state, (3) coining, drawing or extruding the preformed metal part while said metal of said preformed metal part is maintained in the metastable austenitic state at a temperature of 300° F. to 650° F., and (4) quenching the coined, drawn, or extruded metal part at a temperature which allows for the rapid transformation from austenite to martensite.
    Type: Grant
    Filed: June 18, 2007
    Date of Patent: May 21, 2013
    Assignee: Keystone Investment Corporation
    Inventor: Gary L. Anderson
  • Publication number: 20130000788
    Abstract: A method for manufacturing a base material for a wave gear which enables the effective suppression of man-hours and manufacturing cost while providing the required strength and elastic deformation characteristics for an external gear of a wave gear. In this manufacturing method, steel having a carbon content of 0.48% or less is subjected to primary molding by being cold worked into the shape of an external gear for a wave gear. The resulting primary molded article is heated to a temperature range in which the main phase of the metallographic structure thereof forms an austenitic structure. The main phase of the metallographic structure is formed into bainite by carrying out quenching to a predetermined temperature higher than the martensitic transformation starting temperature and maintaining the temperature for a predetermined time. The product is then cooled to normal temperature.
    Type: Application
    Filed: March 14, 2011
    Publication date: January 3, 2013
    Applicant: AISIN SEIKI KABUSHIKI KAISHA
    Inventors: Eiri Nagata, Nobuaki Kurita
  • Patent number: 7691212
    Abstract: Various inexpensive rolling elements for use under high interface pressure such as induction hardened gears are provided, which have improved seizure resistance at tooth flanks and a temper hardness of HRC 50 or more at 300 ° C. To this end, a rolling element is made from a steel material which contains at least 0.5 to 1.5 wt % carbon and 0.2 to 2.0 wt % one or more alloy elements selected from V, Ti, Zr, Nb, Ta and Hf; and in which 0.4 to 4.0% by volume one or more compounds selected from the carbides, nitrides and carbonitrides of the above alloy elements and having an average particle diameter of 0.2 to 5 ?m are dispersed. In such a rolling element, the soluble carbon concentration of a martensite parent phase of a rolling contact surface layer is adjusted to 0.3 to 0.8 wt %, the martensite parent phase having been subjected to induction hardening and low temperature tempering, and one or more of the above carbides, nitrides and carbonitrides are dispersed in an amount of 0.4 to 4.
    Type: Grant
    Filed: March 1, 2004
    Date of Patent: April 6, 2010
    Assignee: Komatsu Ltd.
    Inventor: Takemori Takayama
  • Patent number: 7691213
    Abstract: There is provided an inexpensive rolling element used under high interface pressure such as induction hardened gears, the rolling element being improved in the seizure resistance of its tooth flanks and having a temper hardness of HRC 50 or more at 300° C. To this end, the rolling element is made from a steel material containing at least 0.45 to 1.5 wt % C and one or more alloy elements selected from 0.1 to 0.5 wt % V and 0.3 to 1.5 wt % Cr, and has a rolling contact surface layer having a structure tempered at low temperature in which 2 to 18% by volume cementite disperses in a martensite parent phase formed by induction heating and cooling and containing 0.25 to 0.8 wt % carbon solid-dissolving therein.
    Type: Grant
    Filed: March 1, 2004
    Date of Patent: April 6, 2010
    Assignee: Komatsu Ltd.
    Inventors: Takemori Takayama, Masanari Furumoto, Chikara Nakao, Noriko Morioka
  • Patent number: 7641850
    Abstract: A technique for net shaping gear teeth of a high performance power transmission gear from a powder metal workpiece includes heating a powder metal workpiece in the form of a near net shaped gear blank having gear teeth surfaces above its critical temperature to obtain an austenitic structure throughout its surfaces, isothermally quenching the workpiece at a rate greater than the critical cooling rate of its surfaces to a uniform metastable austenitic temperature just above the martensitic transformation temperature, rolling the gear teeth surfaces of the workpiece to a desired outer peripheral profiled shape between opposed dies, each die having an outer peripheral profiled surface, while holding the workpiece at the uniform metastable austenitic temperature, the gear teeth surfaces undergoing densification, plastic deformation, and strengthening as a result of the rolling operation, and cooling the workpiece through the martensitic range to thereby harden the surfaces of the gear teeth.
    Type: Grant
    Filed: March 17, 2004
    Date of Patent: January 5, 2010
    Assignee: The Penn State Research Foundation
    Inventors: Nagesh Sontti, Maurice F. Amateau, Suren B. Rao
  • Patent number: 7422643
    Abstract: There is provided an inexpensive rolling element used under high interface pressure such as induction hardened gears, the rolling element being improved in the seizure resistance of its tooth flanks and having a temper hardness of HRC 50 or more at 300° C. To this end, the rolling element is made from a steel material containing at least 0.45 to 1.5 wt % C and one or more alloy elements selected from 0.1 to 0.5 wt % V and 0.3 to 1.5 wt % Cr, and has a rolling contact surface layer having a structure tempered at low temperature in which 2 to 18% by volume cementite disperses in a martensite parent phase formed by induction heating and cooling and containing 0.25 to 0.8 wt % carbon solid-dissolving therein.
    Type: Grant
    Filed: September 26, 2005
    Date of Patent: September 9, 2008
    Assignee: Komatsu Ltd.
    Inventors: Takemori Takayama, Masanari Furumoto, Chikara Nakao, Noriko Morioka
  • Publication number: 20080145690
    Abstract: A surface processing method includes the step of increasing a surface hardness of a metal having a nominal composition that includes about 0.21-0.25 wt % carbon, about 2.9-3.3 wt % chromium, about 11-12 wt % nickel, about 13-14 wt % cobalt, about 1.1-1.3 wt % molybdenum, and a balance of iron from a first hardness to a second hardness. For example, the method is used to produce a surface-hardened component that includes a core section having a first hardness between about 51 HRC and 55 HRC and a case section having a second hardness that is greater than the first hardness.
    Type: Application
    Filed: December 15, 2006
    Publication date: June 19, 2008
    Inventors: Tapas K. Mukherji, Michael E. Dandorph, Bruce D. Hansen, Edward J. Karedes
  • Publication number: 20040094234
    Abstract: The present invention is directed to improved methods of reducing the sound level caused by meshing of gear teeth in a gear box, and in particular by reducing distortion caused by heat treatment as used in the manufacturing process of the gear teeth.
    Type: Application
    Filed: November 15, 2002
    Publication date: May 20, 2004
    Applicant: Curtis Machine Company, Inc.
    Inventors: Lloyd Stuart Curtis, Warren Eckelman, Harvey Blattner, Galen Kohn, Rajasekhar Pudi, John Thomas
  • Patent number: 6602358
    Abstract: Disclosed are an outer race for a constant velocity joint, having improved anti-flaking properties and shaft strength, and a process for producing the same. The outer race for a constant velocity joint includes a cup and a serration and comprises by weight carbon: 0.45 to 0.59%, silicon: 0.15 to 0.4%, manganese: 0.15 to 0.45%, sulfur: 0.005 to 0.15%, molybdenum: 0.1 to 0.35%, boron: 0.0005 to 0.005%, aluminum: 0.015 to 0.05%, and titanium: 0.015 to 0.03%, the proportion of the effective case depth in track grooves of the cup being 0.25 to 0.45 in terms of the ratio of the effective case depth t to the wall thickness of the cup w, t/w, the proportion of the effective case depth of the involute serration in its end being 0.20 to 0.50 in terms of the ratio of the effective case depth t to the radius r, t/r. The involute serration in its end preferably has a former austenite grain size of not less than 8 in terms of the grain size number specified in JIS (Japanese Industrial Standards).
    Type: Grant
    Filed: November 18, 1999
    Date of Patent: August 5, 2003
    Assignees: Nippon Steel Corporation, Honda Motor Co., Ltd.
    Inventors: Tatsuro Ochi, Hideo Kanisawa, Kenichiro Naito, Joji Tamura, Masayoshi Saga
  • Publication number: 20030136484
    Abstract: Provided is a quenching method capable of producing quenched articles having little distortion and having a desired hardness. The quenching method with a coolant is specifically so controlled that the surface of the quenching bath is kept under pressure all the time throughout the step of cooling the articles being processed therein.
    Type: Application
    Filed: December 5, 2002
    Publication date: July 24, 2003
    Applicant: Idemitsu Kosan Co., Ltd.
    Inventors: Katsumi Ichitani, Makoto Takeishi
  • Publication number: 20020179205
    Abstract: A planetary carrier supports pinion gears of a planetary gear set via pinion shafts. Each hole in which a pinion shaft is mounted has a shallow hardened wall surface that is hardened by very-high-frequency induction heating and quenching. Therefore, the durability of the pinion shaft-supporting holes of a cold-forged piece or a pressed piece can be improved without thermal strain.
    Type: Application
    Filed: May 22, 2002
    Publication date: December 5, 2002
    Inventors: Kouji Ohbayashi, Kazunari Suzuki, Yoshihisa Yamamoto, Kengo Nomura
  • Patent number: 6488788
    Abstract: A flat plate member with gear portion is formed to a predetermined shape by pressing a flat steel raw material having a composition comprising, by weight, 0.10-0.18% C, less than 0.03% Si, 0.60-1.50% Mn, less than 0.020% P, less than 0.013% S, 0.001-0.004% B and the balance Fe with inevitable impurities, wherein quenching is performed on only the gear portion.
    Type: Grant
    Filed: June 28, 2001
    Date of Patent: December 3, 2002
    Assignee: Aisin Seiki Kabushiki Kaisha
    Inventors: Haruki Ito, Yukio Isomura, Naoyuki Yamada
  • Patent number: 6401941
    Abstract: The rack is made essentially out of thermostructural composite material and comprises a baseplate (12), a partition (14) extending above the baseplate, and a plurality of support arms (20) fixed to the partition and extending substantially horizontally therefrom to their own free ends, so that parts to be treated (A) can be supported in cantilevered-out positions on said arms.
    Type: Grant
    Filed: January 4, 2001
    Date of Patent: June 11, 2002
    Assignee: Societe Nationale d'Etude et de Construction de Moteurs d'Aviation S.N.E.C.M.A.
    Inventor: Jean-Pierre Maumus
  • Publication number: 20020014291
    Abstract: A flat plate member with gear portion is formed to a predetermined shape by pressing a flat steel raw material having a composition comprising, by weight, 0.10-0.18% C, less than 0.03% Si, 0.60-1.50% Mn, less than 0.020% P, less than 0.013% S, 0.001-0.004% B and the balance Fe with inevitable impurities, wherein quenching is performed on only the gear portion.
    Type: Application
    Filed: June 28, 2001
    Publication date: February 7, 2002
    Applicant: AISIN SEIKI KABUSHIKI KAISHA
    Inventors: Haruki Ito, Yukio Isomura, Naoyuki Yamada
  • Patent number: 6330836
    Abstract: A steel for a gear which is formed on a drive plate gear includes; C: 0.32 to 0.38%, Si: 0.1% or less, Mn: 0.60 to 0.90%, P: 0.03% or less, and S: 0.035% or less.
    Type: Grant
    Filed: March 30, 2000
    Date of Patent: December 18, 2001
    Assignee: Fujikiko Kabushiki Kaisha
    Inventors: Hiroshi Watanabe, Masakiyo Ohya, Masato Shibata
  • Patent number: 6315841
    Abstract: Bevel gears having a carbon content of at least about 0.4% by weight, preferably 0.5% by weight are manufactured by a process which includes forging a steel blank having a carbon content of at least 0.4% by weight until a bevel gear precursor having essentially the tooth configuration and dimensions of the desired product gear is obtained, and hardening the teeth of the gear precursor by induction heating without machining of the teeth. The initial forging is precise enough so that no further machining of the teeth is required. This requires forging to a tolerance specified in AGMA class 6. The gear is then induction hardened, first by preheating at a lower frequency, say 10 KHz, then induction heating at a higher frequency, say 50 KHz, in order to obtain a desired hardness profile. The desired hardness profile includes the surface hardness of at least 50, preferably 60, on the Rockwell C scale and a core hardness not over Rockwell C 45, preferably from Rockwell 25 to Rockwell 40.
    Type: Grant
    Filed: December 31, 1999
    Date of Patent: November 13, 2001
    Assignee: Dana Corporation
    Inventors: James S. Fisher, Roland C. Smith
  • Patent number: 6264768
    Abstract: A method and apparatus disclosed for cost-effective net shape precision ausform finishing the engagement surfaces of ball and roller bearings, for enhancing the surface strength and durability of bearing inner and outer races. The method consists of induction heating to austenitize the contacting surface layers of rolling element bearing races, followed by martempering (or marquenching), and then net shape roll finishing of the induction heated contacting surface layers in the metastable austenitic condition to finished dimensional accuracy requirements, and finally cooling to martensite. The apparatus utilizes a fixed vertical through-feed axis for the workpiece bearing race with capability for rotation and linear up and down positioning motion, and two coordinated and controlled laterally-moving infeed axes for roll finishing tooling dies.
    Type: Grant
    Filed: April 23, 1999
    Date of Patent: July 24, 2001
    Assignee: The Penn State Research Foundation
    Inventors: Nagesh Sonti, Suren B. Rao
  • Patent number: 6264886
    Abstract: There is provided a sintered metallic alloy having toughness capable of supporting stress at a point by distributing structure portions having different values of rigidity approximately uniformly without separation of layers different in brashiness. A method of manufacturing the sintered metallic alloy and a sintered alloy gear employing the sintered metallic alloy are also provided. Metallic materials are formed into a predetermined configuration. Then, the metallic materials is sintered in a sintering furnace (14) to make a sintered metallic alloy. Next, the sintered metallic alloy is cooled gradually to an ambient atmosphere of room temperature. Finally, the temperature of the cooled metallic alloy is raised and a toughness stabilizing process is performed in a low-temperature furnace (18) so that structures with high toughness are distributed approximately uniformly.
    Type: Grant
    Filed: October 21, 1998
    Date of Patent: July 24, 2001
    Assignee: JATCO Corporation
    Inventors: Muneo Mizuta, Yasushi Yabe, Yoshihisa Tomihari
  • Patent number: 6129793
    Abstract: A face-gear forging die which can be used to near-net forge face gears is disclosed. The face-gear forging die is constructed from a blank, and is cut to specification using a wire electrical discharge machining (EDM) process. The wire electrical discharge machining process is computer controlled, according to pre-specified instructions. Accordingly, a variety of different-shaped face-gear forging die may be constructed by merely changing the specification's input to the wire Electric Discharge Machining apparatus. The wire Electric Discharge Machining process can also be used to cut the face gear tooth directly, to thereby circumvent the forging procedure. The complex, curved surfaces of the face gear teeth are mathematically approximated with a ruled surface, and the mathematical approximation is input to the wire Electric Discharge Machining apparatus for subsequent execution and forming of the die.
    Type: Grant
    Filed: August 11, 1997
    Date of Patent: October 10, 2000
    Inventors: Jie Tan, Terrell W. Hansen
  • Patent number: 6129794
    Abstract: A method of manufacturing a gear wheel including a shaft and a tooth system. The method includes the steps of hardening and annealing the gear wheel, heating the gear wheel to an annealing temperature, spinning the gear wheel when the annealing temperature is reached, spinning the gear wheel while cooling the gear wheel and grinding the gear wheel to a final size. The method allows the manufacture of gear wheels having an increased service life.
    Type: Grant
    Filed: August 28, 1998
    Date of Patent: October 10, 2000
    Assignee: Asea Brown Boveri AG
    Inventor: Hans Wettstein
  • Patent number: 6026700
    Abstract: A gearset for a gear spindle coupling or the like, and method for forming the same, comprising a sleeve gear and a hub gear which may be ground after surface hardening without the introduction of undesired structural weakening. The sleeve gear includes internal gear teeth and the hub gear includes external gear teeth in mesh with the sleeve gear teeth. Each internal sleeve gear tooth has an internal profile with the tooth height ranging from about 1.9 to about 2.2 divided by the diametral pitch of the sleeve gear, and each external hub gear tooth has a contact height less than the full tooth height. The contact height of the external tooth ranges from about 1.4 to about 1.6 divided by the diametral pitch of the hub gear, with the hub gear tooth region ranging between about 1.4/diametral pitch to about 1.6/diametral pitch. The whole depth of each external gear tooth ranges between about 1.5/diametral pitch to about 1.8/diametral pitch, and the whole depth of each internal gear tooth ranges between about 1.
    Type: Grant
    Filed: June 12, 1998
    Date of Patent: February 22, 2000
    Assignee: Kop-Flex, Inc.
    Inventors: Jon R. Mancuso, Andrew M. Sima, Charles L. Griffin, Robert O. Backus
  • Patent number: 6019857
    Abstract: Power transmission member such as gears with high breaking strength of the edge portion (A) of the root and high spalling resistance of the tooth side (B) is obtained. The work such as gears, etc. is cooled after carburization by plasma carburizing, etc. and the work surface is high-frequency hardened, and for heating at the time of high-frequency hardening, the heating conditions are set in such a manner that the heating temperature at the root becomes higher than that at the tooth side and time for holding to high temperature becomes long. This promotes solid solution of carbonate at the root and increases the remaining austenite volume after hardening (25-35% for a good-rule-of-thumb) as well as improves toughness at the edge. On the other hand, on the tooth side, the remaining austenite volume decreases (5-15% for a good-rule-of-thumb) and spalling resistance improves.
    Type: Grant
    Filed: June 24, 1997
    Date of Patent: February 1, 2000
    Assignee: Mazda Motor Corporation
    Inventor: Akira Mutagami
  • Patent number: 5868878
    Abstract: A workpiece is heated by first forming an ionized gas plasma around the workpiece. A positive potential is applied to the workpiece to accelerate electrons from the plasma into the workpiece. The workpiece is uniformly surface heated by the energy directed into the workpiece by the electrons. The workpiece is cooled by providing a flow of a pressurized liquid material such as carbon dioxide having a triple point. The liquid material is expanded through a nozzle to form solid particles that contact the surface of the workpiece and remove heat from it by subliming.
    Type: Grant
    Filed: August 27, 1993
    Date of Patent: February 9, 1999
    Assignee: Hughes Electronics Corporation
    Inventors: Jesse N. Matossian, John D. Williams, Wilfried Krone-Schmidt
  • Patent number: 5799398
    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.
    Type: Grant
    Filed: September 18, 1995
    Date of Patent: September 1, 1998
    Assignee: The Penn State Research Foundation
    Inventors: Maurice F. Amateau, Nagesh Sonti
  • Patent number: 5785771
    Abstract: A method for manufacturing precision gears (10) including an initial step of providing a shaped workpiece (30.sub.S) defining a plurality of gear teeth (12) and, furthermore, defining a tooth space surface (68) defined by and between adjacent gear teeth (12). Next, a masking tool (60) is assembled in combination with the shaped workpiece (30.sub.S), which masking tool (60) includes a flexible back-plate (64) and plurality of compliant masking segments (62) bonded to and integrated by the flexible back-plate. Each of the compliant masking segments (62) defines a surface geometry (66) which is substantially complementary to the tooth space surface (68), and adjacent compliant masking segments (62) define an open-ended channel (70) therebetween. As assembled, the compliant masking segments (62) are forcibly urged into superposed engagement with the tooth space surfaces (68). In a subsequent step, a layer of masking material (28) is deposited on exposed surfaces of the shaped workpiece (30.sub.
    Type: Grant
    Filed: May 2, 1997
    Date of Patent: July 28, 1998
    Assignee: Sikorsky Aircraft Corporation
    Inventors: George D. Mitchell, Jr., Edward H. Bittner, Walter S. Koscomb, III
  • Patent number: 5690756
    Abstract: A method for producing cast iron gears includes the steps of heating a blank composed of cast iron and having a teeth forming part to such a temperature that at least the teeth forming part is at least austenitized, and hot rolling the teeth forming part of the blank by pressing projecting teeth of a rolling machine against the teeth forming part which is in a hot state and within an austenitized range, while cooling the blank, thereby generating a teeth part in the teeth forming part of the blank. Hot rolling with a low plastic deformation resistance prevents lowering of strength due to the exposure of graphite particles of cast iron and occurrence of quenching cracks and rolling cracks, and improves gear accuracy.
    Type: Grant
    Filed: March 18, 1996
    Date of Patent: November 25, 1997
    Assignee: Toyota Jidosha Kabushiki Kaisha
    Inventors: Yasuyuki Fujiwara, Izuru Yamamoto, Masazumi Onishi, Toshiaki Tanaka, Yoshinari Tsuchiya, Atsushi Danno
  • Patent number: 5667603
    Abstract: A process for hardening a plurality of holed flat parts. The holed flat parts are heated by inserting a cantilever hanger into the holes of the holed flat parts to support them in vertical positions within a furnace. The holed flat parts are then removed from the hanger by inserting a moving fork into the holes of the holed flat parts and moved to a cooling section while being supported in the vertical positions on the moving fork. Then, the holed flat parts in the vertical positions are quenched in the cooling section by blowing a gas downward to them. Also disclosed is an apparatus for practicing the holed flat part hardening process.
    Type: Grant
    Filed: September 1, 1995
    Date of Patent: September 16, 1997
    Assignee: NTN Corporation
    Inventors: Masanori Ichikawa, Tadayoshi Yoshioka, Katsumasa Toyoda, Shinichi Takizawa
  • Patent number: 5656106
    Abstract: An apparatus is disclosed for performing thermomechanical processing of gears in which precise control of the thermal, metallurgical and mechanical action during the forming process is maintained. The apparatus comprises an induction heating system which reaustenitizes the surface of the gear with minimum decarburization, a material transfer system which provides timely operations on the work piece, tooling and fixture adjustments which provide accurate initial conditions for forming, and a process control architecture that provides the precise sequence and timing necessary to achieve metallurgically sound and dimensionally accurate gears. The induction heating cycle can be controlled from the peak, average or minimum gear surface temperature detected with a high response optical pyrometer. An inert environment is maintained around the workpiece during the induction heating and transfer to quenching above the M.sub.s temperature.
    Type: Grant
    Filed: December 21, 1994
    Date of Patent: August 12, 1997
    Assignee: The Penn State Research Foundation
    Inventors: Maurice F. Amateau, G. Dwayne Kidwell, Nagesh Sonti
  • Patent number: 5562785
    Abstract: A disc-shaped material is prepared by punching a high carbon steel plate or soft steel plate, and the disc-shaped material is fixed in position. An outer peripheral portion of the disc-shaped material is heated to a temperature of 400.degree.-500.degree. C. y means of a high frequency heater. The outer peripheral portion of the disc-shaped material is swaged to form a thickened portion by a swaging die and the thickened portion is then spun to plastically form a toothed gear to the outer peripheral portion of the disc-shaped material in two steps of coarse working and finish working by spinning dies. The thus formed toothed gear is further heated as occasion demands to a temperature of about 900.degree. C. for quenching.
    Type: Grant
    Filed: April 18, 1995
    Date of Patent: October 8, 1996
    Assignee: Kubota Iron Works Co., Ltd.
    Inventor: Shigeaki Yamanaka
  • Patent number: 5527400
    Abstract: A method and apparatus for machining a workpiece from a hardened unmachined part includes the use of non-rotating centers in a turning machine, on which the workpiece is mounted. The shape of the dead centers permits less force to be used in support of the workpiece for reducing friction between the rotating workpiece and non-rotating centers, while exerting a maximum amount of radial holding force to reduce runout in the machining operation. Lubrication can be supplied through the dead centers to further reduce friction and/or an anti-friction coating may be applied to the contacting surface of the centers for this purpose. Machining of the hardened part may be controlled by CNC equipment.
    Type: Grant
    Filed: November 14, 1994
    Date of Patent: June 18, 1996
    Assignee: Dana Corporation
    Inventors: Roland C. Smith, James S. Fisher
  • Patent number: 5516376
    Abstract: A hardened surface layer is formed in the region of inner and outer surfaces of a hollow material having a central through hole, then the hollow material is hot-forged into a hollow gear-like forged body by a forging die having a first die element with a piercing punch entering into the central through hole of the hollow material from one side thereof and having a second die element with a piercing punch entering into the central through hole of the hollow material from another side thereof. The forging die forms teeth of the gear on the outer side of the hollow material while producing an annular flash in the central through hole of the hollow material between the piercing punches. A distance between the piercing punches in a closed condition of the forging die defines a thickness of the annular flash which is 0.3 mm or more and no greater than 1.3 times (130%) of a depth of the hardened surface layer.
    Type: Grant
    Filed: May 24, 1994
    Date of Patent: May 14, 1996
    Assignees: Nissan Motor Co., Ltd., Nittan Valve Co., Ltd.
    Inventors: Tetsuo Tsukamoto, Kiyoshi Ohkawachi, Shinji Fushimi, Shunzo Umegaki, Takashi Matsumoto
  • Patent number: 5451275
    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.
    Type: Grant
    Filed: August 4, 1994
    Date of Patent: September 19, 1995
    Assignee: The Penn State Research Foundation
    Inventors: Maurice F. Amateau, Nagesh Sonti
  • Patent number: 5213636
    Abstract: A method for induction heating and quench hardening of helical gears provides a hardness pattern uniformly distributed to a controlled depth across and between the teeth surfaces by means of axial scanning of the workpiece and uniform quenching. Uniform quenching is achieved by directing jets of quench fluid at the workpiece toothed surface at angles horizontally offset from the radial direction.
    Type: Grant
    Filed: June 17, 1991
    Date of Patent: May 25, 1993
    Assignee: Tocco, Inc.
    Inventors: Ronald R. Akers, William D. West