Ntn Corporation

Other

Kikuo Maeda

Mitsuo Sasabe

Yuji Okamoto

Hirokazu Nakashima

Hisashi Ohtsuki

Takashi Tsujimoto

Takumi Fujita

Kenji Tamada

Tomoaki Kawamura

Akio Okayama

Yukio Fujii

Hiroshi Murakami

Masazumi Kobayashi

Chikara Ohki

Keniti Amano

Sadayuki Nakamura

Yoshinobu Akamatsu

Akio Sakaguchi

Toshiyuki Hoshino

Michio Iihara

Yukio Matsubara

Kenichi Ichikawa

Hideshi Nishiwaki

Yoshihiro Sagisaka

Tadatoshi Suzuki

Katsunori Makino

Katsuyoshi Yoshimura

Katsunori Ito

Ryuma Mano

Hiromasa Tanaka

Tosiya Kinami

Yuuki Kataoka

Takuya Atsumi

Shinobu Nasu

A bearing apparatus for wheel with ensured high durability by including a part with improved fatigue strength in a non-hardened portion includes an outer member, an inner member, and a roller. The inner member includes a hub ring made of steel and having a wheel attachment flange formed. The hub ring has a hardened portion hardened to attain at least 50 HRC as a result of quench hardening and a non-hardened portion which is a portion other than the hardened portion. Compressive stress in a range from at least 50 MPa to at most 500 MPa remains in the surface of the non-hardened portion.

Bearing apparatus for wheel

A process for manufacturing a rolling contact member comprises preparing a steel member consisting of a steel containing 0.7 mass % or more of carbon; performing hot forging of the steel member prepared in the steel member preparation step to thereby obtain a blank ring as the first forged member; performing turning of the blank ring obtained in the hot forging step to thereby remove part of the blank ring; and performing cold forging of the blank ring wrought in the first turning step to thereby obtain a stepped ring. In the steps subsequent to the cold forging step, on the stepped ring, the area wrought in the first turning step is not subjected to cutting.

Process for manufacturing rolling contact member, process for manufacturing rolling bearing, raceway member of rolling bearing and rolling bearing

The invention provides a deep groove ball bearing which exhibits a long life even in a high-temperature environment or an environment involving the penetration of water in spite of its low alloying element content. The outer race, inner race and ball constituting the bearing are made of a steel which contains 0.3 to 0.4% of carbon, 0.3 to 0.7% of silicon, 0.3 to 0.8% of manganese, 0.5 to 1.2% of nickel, 1.6 to 2.5% of chromium, 0.1 to 0.7% of molybdenum and 0.2 to 0.4 of vanadium with the balance consisting of iron and impurities and in a total content of silicon and manganese of 1.0% or below, a total content of nickel and chromium of 2.3% or above and a total content of chromium, molybdenum and vanadium of 3.0% or below. Surface hardened layers are formed in the outer race, inner race and ball respectively and the surface hardened layers exhibit hardness of 725 to 800 HV, while the maximum particle size of carbides dispersed in the surface hardened layers is 10 &#x3bc;m or below and the area ratio thereof is 7 to 25%. Further, the inner parts exhibit hardness of 450 to 650 HV.

Rolling member, rolling bearing and process for manufacturing rolling member

There is provided a wheel support bearing assembly in which at least one of the outer member () and inner member, which includes a wheel mounting flange (), is, after having been forged, air cooled or thermally refined. The respective rolling surfaces of the outer member () and the inner member are hardened to have a predetermined surface hardness. The root radial dimension of the section of a groove bottom arc in the serrations () of the hub unit () is regulated to a value within the range of 0.2 mm to 0.8 mm.

Wheel support bearing assembly and method of making the same

A wheel support bearing assembly with a hub axle of enhanced strength and a durability under a rotational bending condition as well as weight reduction, and without changing a shape and a dimension of a wheel mounting flange nor deteriorating a surface runout, and a manufacturing method thereof. A surface hardness is set to 20 HRC or more and than 35 HRC or less by applying an air cooling or a thermal refinement after hot forging a raw material of the hub axle, and a shot peening treatment is applied to an inner diameter portion of the hub axle.

Wheel support bearing assembly and manufacturing method thereof

A manufacturing method of a thin component is characterized by heating a thin component, and thereafter, while sizing with molds and using molds as cooling media, performing one of quenching and isothermal transformation processes on thin component. Thus, a manufacturing method of a thin component without warping or deformation in heat treatment with even and high hardness, a bearing ring, a thrust needle roller bearing, a manufacturing method of a rolling bearing ring, a rolling bearing ring, and a rolling bearing can be obtained.

Manufacturing method of thin component, bearing ring, thrust needle roller bearing, manufacturing method of rolling bearing ring, rolling bearing ring, and rolling bearing

A method is provided for producing a roller thrust bearing having a plurality of rows of rollers, the bearing featuring reduced differential slip, reduced friction and wear, and increased longevity without flaking. The method includes forming a cage to accommodate the rollers, crowning the rollers, and arranging the rollers in pockets such that the rollers held by a pocket have respective end surfaces in direct contact with each other.

Method of producing a roller thrust bearing having a plurality of rows of rollers

A rolling bearing () having an outer ring (), an inner ring (), and a plurality of rolling elements, wherein at least one of the members, the outer ring (), inner ring () and rolling elements (), has a nitrogen rich layer and the grain size number of austenite crystal grains is in the range exceeding the number

Rolling bearing

A steel-member manufacturing facility that can suppress distortion occurring in a quenching process while preventing increase in manufacturing cost includes: a die-cutting apparatus to form a washer; a high-frequency induction heating apparatus for quenching purpose as well as a mold-constraining cooling apparatus that heat the washer as formed and thereafter cool the washer so as to quench-harden the washer; and a high-frequency induction heating apparatus for tempering purpose that heats the quench-hardened washer so as to temper the washer. The high-frequency induction heating apparatus for quenching purpose can heat the washer by induction heating to the temperature of at least Apoint. The mold-constraining cooling apparatus uses a mold to constrain the heated washer while using the mold as a cooling member, thereby cooling the washer to the temperature of at most Mpoint.

Steel-member manufacturing facility, thin bearing-member and thrust bearing

A full-type rolling bearing that can be used under the conditions of high-speed, heavy-load and lowered viscosity of lubricating oil is provided. The full-type rolling bearing is formed of an outer ring, an inner ring and rollers made of steel, at least one of the outer ring, inner ring and rollers has a carbonitrided layer in its surface layer, and the austenite crystal grain size number of the surface layer is larger than 10.

Full-type rolling bearing and roller cam follower for engine

There is provided a roller thrust bearing providing reduced differential slip, free of significant friction and wear, and providing increased longevity against flaking. The present invention provides a thrust bearing in the form of a roller thrust bearing including at least two radially arranged rows of rollers and a cage holding the rollers, the rollers including at least one roller crowned.

Roller thrust bearing

There is provided a rolling component formed of a steel material of the medium carbon steel level that provides a rolling life improved to be comparable to that of bearing steel and also provides improved characteristic against surface-cracking, and a power transmission component including the rolling component. To achieve this, the rolling component is formed of steel having an induction hardened portion having a stress intensity factor range associated with tension associated-fatigue crack extension that has a lower limit &#x394;Kth of 6.2 Mpa&#x221a;m.

Rolling part and power transmission part

A tapered roller bearing and an automotive gear shaft support device can ensure a long endurance life even in the state in which debris is mixed. On the surfaces of an outer ring, inner ring, and tapered rollers formed from carburized bearing steel having an oxygen content of 9 ppm or less, carbo-nitrided layers having a carbon content of 0.80 wt % or over, a Rockwell hardness HRC of 58 or over, and a residual austenite content of 25&#x2013;35 vol % are formed to increase mechanical properties and fatigue characteristics of the parts and to stably maintain the carbo-nitrided layers on the surfaces of the parts to a quality having suitable toughness, thereby markedly improving the endurance life of the tapered roller bearing in a state in which debris is mixed.

Tapered roller bearings and gear shaft support devices

A constant velocity universal joint for use with a propeller shaft which reduces its weight and size as well as facilitates assembling a stub shaft, thereby reducing the number of parts used and improving rotational balance. The universal joint, comprising: an outer ring with a cup-shaped enlarged diameter portion having track grooves formed on an inner peripheral surface and with a hollow reduced diameter portion integrated with the enlarged diameter portion; an inner ring having track grooves formed on an outer peripheral surface; balls, interposed between the track grooves of the inner and outer rings, for transmitting torque; a cage, accommodated in an annular space between the inner and outer rings, for holding the balls. The universal joint makes possible to form a unit provided with a stub shaft, having a shaft portion inserted from an open end portion of the enlarged diameter portion of the outer ring to mate with the inner ring to enable torque transmission and having an enlarged diameter portion on an end portion extending from the shaft portion, and provided with a boot, attached to the open end portion of the enlarged diameter portion of the outer ring and the shaft portion of the stub shaft, for sealing the joint.

Growing community of inventors

Kuwana, Japan

Kikuo Maeda