Ntn Corporation

Sumitomo Metal Industries, Inc.

Jfe Steel Corporation

Kazuhiko Yoshida

Akira Wakita

Keisuke Sone

Tatsuhiro Goto

Hirokazu Ooba

Hisaaki Kura

Isao Hirai

Tatsuro Sugiyama

Kenji Terada

Akio Sakaguchi

Takayasu Takubo

Shigeyoshi Ishiguro

Hiroaki Makino

Kenji Aihara

Kazuhiro Muramatsu

Yasuhide Fujioka

Kiyohiro Itou

Masato Chokyu

Takaaki Toyooka

Kazukuni Hase

Takashi Koike

Kenta Yamazaki

Shintaro Suzuki

Kenichi Iwamoto

Takafumi Iwamoto

Mika Kohara

Katsuyuki Ikei

Kiyoshi Uwai

Hideto Kimura

Kohei Yoshino

Toyofumi Hasegawa

Hiroo Morimoto

Masafumi Osugi

Hiromi Hayashi

Hideo Takeshita

Hiroki Mukai

Hideki Kondou

Shogo Okada

Toshio Kawasaki

Toshiki Suwa

Hiroyuki Uchida

Kenji Ouwa

Kazuho Mimura

Rikuou Takagi

A coating film having excellent adhesion, even without the presence of a chemical conversion film treatment as an undercoat, and a metal automotive part having the coating film. A powder is deposited by powder-coating onto the surface of a metal automotive part that has been quenched after simultaneously forging, and tempering the metal automotive part and bake-hardening the deposited powder to form a skin film on the surface of the metal automotive part. The surface of the metal automotive part before the powder is powder-coated thereon is a work-hardened material surface that has not been subjected to a chemical conversion filming treatment.

Method for forming coating film on constant velocity universal joint

A hollow shaft, which is usable with a constant velocity universal joint, has an increased static torsional strength and torsional fatigue strength of a small diameter portion (small diameter portion having a smooth outer peripheral surface) formed near a spline at an end portion of the hollow shaft, and has a reduced manufacturing cost. The hollow shaft is molded by plastic working from a tubular blank, and subjected to quench hardening treatment. The quench hardening treatment includes carburizing and quenching treatment. The hollow shaft includes a softened section formed in a part of the hollow shaft by local heating treatment after carrying out the carburizing and quenching treatment.

Hollow shaft and constant velocity universal joint

Provided is a cage () for a constant velocity universal joint, which is formed into a ring shape with a substantially uniform thickness, including a plurality of pockets () formed in a circumferential direction of the cage (), for receiving torque transmitting balls, respectively, the cage () being formed of carbon steel including 0.41 to 0.51 mass % of C, 0.10 to 0.35 mass % of Si, 0.60 to 0.90 mass % of Mn, 0.005 to 0.030 mass % of P, and 0.002 to 0.035 mass % of S, with the balance being Fe and an element inevitably remaining at the time of steelmaking and refining, the cage () being subjected to carburizing, quenching, and tempering as heat treatment, each of the plurality of pockets () having a side surface () finished after the heat treatment.

Cage for constant velocity universal joint, fixed type constant velocity universal joint incorporating same, and drive shaft incorporating said fixed type constant velocity universal joint

A fixed type constant velocity universal joint comprises a ball and a lubricating grease sealed therein. A surface roughness of the ball is set to Ra 0.15 &#x3bc;m or less and a surface roughness of a counterpart surface on which the ball rolls is set to be higher than the surface roughness of the ball. An additive composition of the lubricating grease comprises a base oil, a diurea compound, molybdenum dithiocarbamate, zinc dialkyldithiophosphate, melamine cyanurate, molybdenum disulfide, and calcium salt of alkylaromatic sulfonic acid.

Fixed-type constant velocity universal joint

An eight-ball fixed type constant velocity universal joint of an undercut free type is capable of increasing a torque capacity at high operating angles while securing durability at low operating angles. When a distance between a center of a track groove and a center of a ball is denoted by Rt, and when an axial distance between the center of the track groove and a joint center plane is denoted by F, a ratio R1 of F to Rt is set to fall within a range of 0.061&#x2266;R1&#x2266;0.087. When a radial offset amount, which is a distance between the center of the track groove and a joint center axial line is denoted by fr, a ratio R3 of fr to Rt is set to fall within a range of 0.07&#x2266;R3&#x2266;0.19. When an effective cured-layer depth with Hv 513 is denoted by Di and the diameter of the ball is denoted by d, a bottom surface of a track groove of an inner joint member includes a cured layer with an effective cured-layer depth ratio Di/d of at least 0.111 or more.

Fixed type constant velocity universal joint

An outer member of a constant velocity universal joint suppresses occurrences of cracking in a joining portion and has stable quality. The outer member includes a cup section having track grooves formed therein, and a shaft section having one end coupled to a bottom portion of the cup section. By joining members having different carbon contents and performing induction hardening on the members, a hardening heat-affected portion affected by the induction hardening, a hardening heat-unaffected portion unaffected by the induction hardening, a joining heat-affected portion affected by heat generated during the joining, and a joining heat-unaffected portion unaffected by the heat generated during the joining are formed. A martensitic structure is eliminated from the hardening heat-unaffected portion of the high carbon content member and is the joining heat-affected portion at an end portion including a joining end surface that is to be joined to the low carbon content member.

Outer member of constant speed universal joint

A shaft part is formed with a rolling groove () on which rolling elements () roll. At least the rolling groove () is induction hardened with no generation of black colored oxidized scale after the induction hardening. A surface of the induction hardened rolling groove () is used 'as is' as a rolling surface. The surface roughness Ra of the induction hardened surface 'as is' of the rolling groove () is less than 1.0. The ratio of effective hardened depth of a hardened layer is between 0.15 and 0.45.

Shaft part formed with a rolling groove

A fixed type constant velocity universal joint of an eight-ball undercut-free type has improved torque capacity at high operating angle while ensuring durability at low operating angle. Centers of a track groove () of an outer joint member and a track groove () of an inner joint member are respectively separated from a center plane (P) toward axially different sides, and are offset away from a joint center axis (X) to a radially opposite side relative to grooves (). When Rt represents a distance between a center of a ball () and the center of groove (), and F represents an axial distance between plane (P) and the center of groove (), a ratio Rbetween F and Rt is 0.061&#x2266;R&#x2266;0.087. When fr represents a radial offset amount as a distance between axis (X) and the center of groove (), a ratio Rbetween fr and Rt is 0.07&#x2266;R&#x2266;0.19.

Fixed uniform-motion universal joint

A power transmission shaft includes a torque-transmission teeth portion formed on an outer peripheral surface on an end portion side, and a smooth portion formed on the outer peripheral surface adjacent to the torque-transmission teeth portion so as to have a stepwise reduced diameter. A ratio of a minimum diameter of the smooth portion to a minimum diameter of the torque-transmission teeth portion is set to 0.9 or more and 1.02 or less. Further, the torque-transmission teeth portion and the smooth portion undergo heat treatment so as to form a heat-treated hardened layer. The heat-treated hardened layer is formed to increase in depth from a side of the torque transmission teeth portion to a side of the smooth portion. At least a minimum diameter portion of the smooth portion undergoes full hardening.

Power transmission shaft, drive shaft, and propeller shaft

A method is directed to a production of a bearing device for a wheel including an inner member and an outer member rotatable relative to each other through a plurality of rolling elements, in which a component part forming one of the inner member and the outer member is a hot forged product. In the practice of this method, during or at the end of a hot forging step for hot forging the component part, a portion of the component part is cooled by spraying a coolant or by controlling an atmospheric temperature, to thereby render a matrix of the component part to represent a standard structure and render a surface portion of the component part to represent a non-standard structure.

Process for producing bearing device for wheel

In a constant velocity universal joint component and a manufacturing method thereof capable of achieving increased strength without significant procedural changes, and that can contribute to size reduction and weight reduction, a sharp-angled portionis formed by machining after cold plastic working is applied. A carburization process is then performed in which surface carbon concentration of 0.45 mass % to less than 0.60 mass % is obtained. Quenching is then performed. High-frequency induction hardening is subsequently performed.

Constant velocity universal joint component and manufacturing method thereof

A constant velocity universal joint has high strength and capable of suppressing deformation caused by quenching at an opening end portion of a track groove of an outer joint member. In an undercut-free constant velocity universal joint in which a track groove in a cup portion of the outer joint member has a hardened layer formed by induction quenching, an opening end surface is protruded by a protruding amount t in an axial direction from a groove bottom of the track groove in a relief surface. The protruding amount t satisfies a relation of t=0.037d to 0.185d when a diameter of a torque transmission ball is represented by d. The opening end surface in a protruded portion and an outer surface of the cup portion continuous to the opening end surface have an unhardened layer free from hardening by quenching.

Constant velocity universal joint

In a fixed type constant velocity universal joint, a center of each of guide grooves of an outer joint member is offset to a position of being spaced apart from a joint central plane to a joint opening side by an axial distance, and is spaced apart from a joint central axis line to an opposite side in a radial direction with respect to each of the guide grooves by a radial distance. Further, a center of each of guide grooves of an inner joint member is offset to a position of being spaced apart from the joint central plane to a joint innermost side by the axial distance, and is spaced apart from the joint central axis line to the opposite side in the radial direction with respect to each of the guide grooves by the radial distance.

A joint outer ring of a constant-velocity joint has a stem portion protruding from of a cup portion and inserted to a through hole of a hub in a bearing device. The joint outer ring has an abutment face abutting against an end face of a bearing inner ring fitted to an outer periphery of the hub in an outer bottom face of the cup portion, and is composed of a forged product of a steel material. The joint outer ring has a base material portion composed of a standard structure and an outer surface layer partially formed as a non-standard structure portion. The non-standard structure may be a tempered martensite structure, or a mixed structure including the tempered martensite structure and at least one of an upper bainite structure and a lower bainite structure.

Constant velocity joint

A bearing device for a wheel enabling the easy control of quality since there is no possibility of cracking even if caulking is applied thereto. The bearing device comprises an outer ring having double rows of raceway surfaces on the inner periphery thereof, an inner member having raceway surfaces opposed to the raceway surfaces, and balls interposed between the double rows of raceway surfaces opposed to each other. The inner member further comprises a HUB ring and an inner ring. Caulking is applied to the HUB ring to join it to the inner ring. The grain size number of the austenite grains of a caulked section is at least 6.

Bearing device for wheel

Growing community of inventors

Iwata, Japan

Kazuhiko Yoshida