Nsk Corporation

Manabu Ohori

Susumu Tanaka

Kenji Yamamura

Akihiro Kiuchi

Shigeru Okita

Kouji Ueda

Koji Ueda

Keijiro Yamaguchi

Nobuaki Mitamura

Takashi Murai

Satoshi Kadokawa

Kyozaburo Furumura

Yukio Ohura

Akira Iida

Hisashi Kawamura

Kikuaki Kamamura

Masaaki Takagi

A brass is a base material, and a material containing Mn and Si is cast to make a ring material. Ametallic structure in the cross section of the ring material is under a condition where an intermetallic compound Mn Si is uniformly and finely scattered and precipitated in the base material (brass composed of &agr;- and &bgr;-phase). A machined retainer provided by matching said material has an excellent sizing precision, sound affect resistance.

Retainer

A rolling bearing having excellent corrosion resistance and having a long life for use in airplanes is provided. The constituent parts of the rolling bearing are made from an alloy steel containing Cr which is required for the improvement of a rolling contact fatigue life at a high temperature and is most effective for providing steels with corrosion resistance when 7.0% or more to 16% or less on a weight percent basis is provided. The amount of a residual austenite on the surface of the completed product is from 6% or more and, preferably, 35% or less by stabilizing the residual austenite.

Rolling bearing

A fine nitride layer comprising a compound layer and a diffusion hardened layer of hardness being Hv900 or higher is formed, through a low temperature nitriding method at temperature in the range of 300 to 400&deg; C., in a guiding part. The guiding part guides the circumferential surfaces of retainers to and is formed at any one part of inner ring raceways to and outer ring raceways to as well as the inner circumferential surfaces of the outer rings to , to thereby realize such rolling bearings at low cost, having excellent abrasion resistance, and good corrosion resistance, if needed.

Rolling bearing and method of making the same

In a steel cage for rolling bearing which is nitrided to form a compound layer on the surface thereof, when the thickness of a dense layer in the compound layer is predetermined to a range of from 3 &mgr;m to 20 &mgr;m, the abrasion can be inhibited, improving the abrasion resistance. Further, when a porous layer which acts as a lubricant reservoir is predetermined to a range of from 2 &mgr;m to 25 &mgr;m, the exhaustion of lubricant can be inhibited, improving the seizing resistance.

Cage for rolling bearing

In a balling bearing of small diameter equipped with an outer race and an inner race , and a plurality of rolling elements disposed between the outer race and the inner race , at least rolling element is composed of a steel of Cr concentration being 8 wt % or higher, and the surface thereof is formed with a layer of N concentration being a range of 3&lE;N %&lE;0.26&times;Cr %&plus;4.42.

Rolling bearing apparatus

The present invention provides a rolling bearing having an excellent corrosion resistance and toughness which can fairly operate at a high rotary speed. At least the inner race is formed by a titanium alloy, and the rolling elements are formed by ceramics. Alternatively, at least one of the inner race and the outer race is formed by a &bgr; type titanium alloy. The percent cold working of the &bgr; type titanium alloy is predetermined to not less than 20% or a range of from 5 to 20%. The cold working is followed by shot peening. Further, the surface hardness Hv is predetermined to not less than 600. The volumetric ratio of residual &bgr; phase in the &bgr; type titanium alloy is predetermined to a range of from 30 to 80%.

The rolling bearing according to the invention comprises a dense nitride layer formed on the surface layer of the rolling elements and optionally an optimum carbonitride layer formed on the races. In this arrangement, the deterioration of durability due to vibration or impact load during transportation can be prevented, not to mention improvement of stillness. Further, the deterioration of impact resistance required for hybrid bearing can be prevented. The release of pilot pressure and defective of acoustic properties due to electrostatic attraction of dust can be prevented. At the same time, the rolling element of the invention comprises a compound layer having an extremely high hardness formed uniformly, making it possible to finish to a high precision. Moreover, a great effect can be exerted of preventing the change of properties with time at high temperature or the deterioration of acoustic properties under other severe working conditions. A novel rolling bearing is provided comprising an outer race, an inner race and a plurality of rolling elements or comprising an outer race, a shaft and a plurality of rolling elements, characterized in that the rolling elements have a dense nitride layer on the finished surface thereof and the nitride layer comprises a compound layer having a hardness Hv of 900 or more and a diffusion-hardened layer.

In view of the fact that, when backup roll bearings which have been found satisfactory in the purity thereof in the sample evaluation through observations using a microscope are checked many times for the top surface layer portions of the raceway surfaces thereof according to an ultrasonic detecting method, on quite rare occasions, there can be found a bearing which contains one or more inclusions each having a size of as large as several hundreds &mgr;m, and such inclusions give rise to occurrence of a short-life bearing as a finished product, a range expressed by 2% Da depth&times;raceway surface is used as a test piece volume and the size of a non-metallic inclusion existing in the test piece volume is restricted to a length less than 500 &mgr;m, preferably, less than 100 &mgr;m. Here, the term &ldquo;2% Da depth&rdquo; means a depth up to 2% of a rolling element mean diameter from the surface of an inner or outer race of a bearing.

A ball-and-roller bearing is disclosed having an inner ring, an outer ring arranged on the axis of the inner ring and rotating around the co-axis relative to the inner ring, and a rolling body interposed between the inner ring and the outer ring and rolling with rotation of the outer ring relative to the inner ring. One of the inner ring, the outer ring, and the rolling body has a core member made from an alloy containing iron, at least one of 0.2 to 1.0% by weight of silicon and 0.2 to 1.5% by weight of manganese, 7.0 to 11.0% by weight of chromium, 1.5 to 6.0% by weight of molybdenum, and 0.5 to 8.0% by weight of cobalt, and a case hardened surface layer. Also disclosed is the method of manufacturing the bearing by forming a core member of the alloy, forming a case hardened layer containing 0.9 to 1.5% by weight of carbon in a surface region of the core member by applying to the core member a carbonizing or carbonitriding treatment, a hardening treatment, and a tempering treatment under high temperatures, and assembling the inner ring, the outer ring and the rolling body such that the inner ring and the outer ring are positioned on the same axis and the rolling body is between the inner ring and the outer ring.

Ball-and-roller bearing and method of manufacturing the same

A rolling device includes: an outer member; an inner member; and a plurality of rolling elements arranged between the outer and inner members, the outer member having a first contact surface which contacts the rolling elements, the inner member having a second contact surface which contacts the rolling elements, each of the rolling elements rolling against the first and second contact surfaces. At least one of the outer member, inner member, and rolling elements is formed of steel containing: C of less than 0.6 wt %; Cr of 10.0 wt % to 22.0 wt %; Mn of 0.1 wt % to 1.5 wt %; Si of 0.1 wt % to 2.0 wt %; N from 0.05 wt % to less than 0.2 wt %; Mo of 0 to 3.0 wt %, and V of 0 to 2.0 wt %; and the balance Fe and inevitable impurities, the steel satisfying C %+N %.gtoreq.0.45 wt %. The rolling device has excellent characteristics in fatigue strength, wear resistance, corrosion resistance, and acoustic characteristic.

Rolling bearing and rolling device

At least one of the components of a rolling member used in a manner in which it is rolled or slid with a mated member is made of carbon steel containing 0.8%-0.9% by weight of C, 0.1%-0.7% by weight of Si, 0.5%-1.1% by weight of Mn, and 0.1%-0.6% by weight of Cr and Fe substantially in the remaining part, wherein an ideal critical diameter DI value calculated from the compositions is 1.5-4.0, and the retained austenite amount after hardened heat treatment is 8%-22% by volume. The value DI is determined by the following equation:

Rolling member and rolling device comprising the same

In an ultrasonic detecting method for a bearing ring in which a bearing ring 2 and an ultrasonic detection probe 3 are disposed within ultrasonic transmission medium such as water, then ultrasonic wave is transmitted from the ultrasonic detection probe 3 to the bearing ring 2, and a defect of the bearing ring 2 is detected on the basis of an ultrasonic wave echo reflected from the bearing ring 2, wherein at least a defect in a range from the surface of the bearing ring 2 to a position beneath by 2 mm from the surface of the bearing ring which is deeper than a maximum shearing stress position of the bearing ring 2 is detected by an angle beam method with an incident angle in a range of 10 to 30.degree., preferably in a range of 25 to 30.degree., and a defect in a range deeper than the range detected by the angle beam method is detected by a normal beam method with an incident angle in a range of 0 to 10.degree., preferably in a range of 0 to 5.degree., thereby to detect a defect in the entire section of the bearing ring 2.

Ultrasonic detecting method for bearing ring

A rolling bearing includes a rolling element made of a steel containing 0.9 to 1.1 wt. % C, 0.1 to 0.5 wt. % Si, 0.2 to 0.8 wt. % Mn, 1.0 to 1.8 wt. % Cr, with the balance being Fe and inevitable impurities. In the rolling bearing at least the surface of the rolling element includes carbides having an area fraction of 5% to 15%; of these carbides, carbides having an averaged particle diameter of 0.5 .mu.m or more share 50% or more of the area fraction of all the carbides; and of the carbides, carbides having an averaged particle diameter of 1 .mu.m or more share 2% or less of the area fraction of all the carbides; and wherein the rolling element has at least a Vickers surface hardness HV of 750 to 900.

Growing community of inventors

Kanagawa, Japan

Manabu Ohori