Ntn Corporation

Kyodo Yushi Co., Ltd.

Mika Kohara

Takayuki Kawamura

Shinichi Takabe

Kenji Tamada

Tatsuro Sugiyama

Natsuhiko Mori

Keisuke Sone

Kazuhiko Yoshida

Teruaki Fujio

Tomoshige Kobayashi

Hiroyuki Noda

Yuji Onuki

Tsuyoshi Ueno

Takahiro Okuno

Hajime Asada

Masahide Miyata

Michitaka Yoshihara

Provided is a boot mounting method for a constant velocity universal joint in which a boot end portion is mounted and fixed to a mating member made of metal. After the boot end portion is fitted over a receiving surface being a radially outer surface of the mating member, a high-frequency induction heating coil having a ring shape is fitted over the boot end portion. Only a top portion of the receiving surface of the mating member is heated by high-frequency induction through application of a high-frequency current to the high-frequency induction heating coil. With this action, a mounting surface being a radially inner surface of the boot end portion and the receiving surface being the radially outer surface of the mating member are integrally joined to each other.

Boot attachment method and constant velocity universal joint

The invention provides a grease composition for constant velocity joints, which contains (a) a base oil, (b) a diurea thickener, (c) benzotriazole and/or a derivative thereof, and (d) a phosphate and/or an amine salt thereof; and a constant velocity joint where the grease composition is packed.

Grease composition for constant velocity joints and constant velocity joint charged with the grease composition

A fixed type constant velocity universal joint includes an outer joint member having eight curved track grooves, an inner joint member having eight curved track grooves, eight torque transmission balls, and a cage configured to hold the torque transmission balls in pockets. A curvature center of each of the track grooves of the outer joint member and a curvature center of each of the track grooves of the inner joint member are offset from a joint center by an equal distance to opposite sides in the axial direction. The joint has grease sealed therein. Initial pocket gaps between the pockets and the balls each have a positive value. The grease has an initial consistency equivalent to consistency number 1 or 2, and a mixture stability of from 390 to 440.

Fixed constant velocity universal joint

A lubricant composition capable of effectively preventing a rolling surface of a bearing from flaking owing to hydrogen embrittlement. The bearing is lubricated with the lubricant composition. The lubricant composition is lubricating oil or grease. The lubricant composition contains a molybdate. The lubricant composition also contains an organic acid salt. At least one molybdate is selected from sodium molybdate, potassium molybdate, and lithium molybdate. The organic acid salt is a sodium salt of an organic acid having one to 20 carbon atoms. 0.01 to 5 wt % of the molybdate is added to the entirety of the lubricant composition. 5 wt % to 70 wt % of the organic acid salt is added to the addition amount of the molybdate. The lubricant composition forms a film containing a molybdenum compound in addition to an iron oxide film on a worn surface of the bearing.

Lubricant composition and bearing using same

There is provided a constant velocity universal joint having excellent durability at high temperature while using a boot made of silicone rubber that does not include cerium oxide or other rare earth element-containing compound. The constant velocity universal joint is provided with an outer joint member (), an inner joint member (), a shaft () coupled to the inner joint member (), and a boot () mounted directly or via another member to the outer joint member () and the shaft (), the boot () being a molded article of a silicone rubber composition including silicone rubber, iron oxide, and titanium oxide and not including a rare earth element-containing compound. The silicone rubber composition furthermore includes barium zirconate as required.

Constant velocity universal joint

A constant-velocity universal joint includes an outer joint member; an inner joint member arranged in an inside of the outer joint member; and torque transmitting members. At least one of the outer joint member and the inner joint member comprises track grooves that are engaged with rolling surfaces of the torque transmitting members. At least one of the components of the constant-velocity universal joint is formed of a metal sintered compact. The metal sintered compact has a relative density of 80% or more and less than 100%. The metal sintered compact comprises a hardened layer formed on a surface thereof through heat treatment. Among the components each formed of the metal sintered compact, a component having a ring shape is subjected to a cold rolling process.

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

The present invention provides a lubrication system that improves the force of retaining a lubricating component of a foamed lubricant, is capable of minimizing the amount of exudation of the lubricating component which occurs owing to deformation of the foamed lubricant, is capable of compensating for a lubricating function even when the lubricating component exudes insufficiently from the foamed lubricant, and is capable of complying with a demand that the lubrication system has a long life and can be produced at a low cost. The lubrication system comprises a foamed lubricant containing a lubricating component in a resin thereof which foams, hardens, and becomes porous and a grease for auxiliary lubrication which is present together with the foamed lubricant in a portion to be lubricated. The grease for auxiliary lubrication satisfies a condition that (1) a penetration thereof is not less than 175 and less than 285 or that (2) a mixing ratio of a thickener to the grease for auxiliary lubrication is not less than 10 wt % and less than 40 wt %. As shown in the drawings, a foamed lubricant () and a grease () for auxiliary lubrication are present together inside a universal joint.

Lubricating system and universal joints with the system

A lubricating having a foam lubricant that minimizes exudation of the lubricating component caused by deformation of the foam lubricant, is excellent in initial lubrication, has a long life, has a low cost, and is excellent in the productivity thereof; a bearing utilizing the lubricating system; a universal joint utilizing the lubricating system; and a process for the production thereof. A lubricating system includes a foam lubricant () containing a lubricating component in a resin thereof which foams, hardens, and becomes porous and a lubricant () for initial lubrication which is present together with the foam lubricant () in a portion to be lubricated. The lubricant () for initial lubrication consists of grease having a worked penetration not less than 300 or having a degree of oil separation not less than 0.7 wt % when the grease is left 24 hours at 70&#xb0; C.

Lubricating system, bearing utilizing the system, universal joint utilizing the system, and process for production thereof

A lubricant composition capable of preventing a rolling surface of a bearing from flaking owing to hydrogen embrittlement. The bearing is lubricated with the lubricant composition which is a lubricating oil or grease. The lubricant composition contains a molybdate and an organic acid salt. At least one molybdate is selected from sodium molybdate, potassium molybdate, and lithium molybdate. The organic acid salt is a sodium salt of an organic acid having one to 20 carbon atoms. The lubricant composition forms a film containing a molybdenum compound in addition to an iron oxide film on a worn surface of the bearing or on a fresh surface of an iron-based metal generated by wear. The bearing is used as a rolling bearing for use in electric parts and auxiliary machines of a vehicle. The bearing is also used as a bearing, for a motor, in which the lubricant composition is sealed.

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Shizuoka, Japan

Mika Kohara