Nsk Corporation

Banda Noda

Tatsunobu Momono

Yasushi Mutoh

Magozou Hamamoto

Yasushi Muto

Takashi Ogawa

Takashi Murai

Hideki Koizumi

Toshihisa Ohata

Yasuhisa Terada

Hiroshi Ishiwada

Takayuki Miyagawa

Kenji Okuma

Eiichi Takahashi

Yasushi Mutou

Kazuhiro Fujiu

Toshio Matsushima

Setsu Kawaguchi

Yasuyuki Muto

The frequencies generated based on the undulations existing on the inner and outer ring raceways and on the rolling surface of the balls are out of coincidence with the rotational frequency itself of the rotation member supported by the rolling bearing, and with a frequency component which is a multiple of the rotational frequency, or kinds of frequencies generated due to the undulations are out of coincidence with each other in the natural frequency domain of a rotation system which is a rotation supporting portion having the rolling bearing incorporated therein, whereby without using a special grease, the self-excited frequency of the rolling bodies hardly grows to abnormal vibration, and a rolling bearing having sufficient durability and causing no abnormal vibration and noise even if used at low temperature is realized.

Rolling bearing

The pocket surface of a pocket with a ball stored therein has a pair of first pocket surfaces respectively formed inside a pair of pawls and a second pocket surface situated between the two first pocket surfaces. The second pocket surface is formed as a spherical-shaped concave surface having a radius of curvature the center of curvature of which is the rotation center of the ball in a no-load state. Each of the first pocket surfaces has a center of curvature shifted from the center of curvature of the second pocket surface toward the opposite side to the entrance (opening) of the pocket by an axially shifting quantity h , and each of the first pocket surfaces is formed, starting from the present center of curvature, as a spherical-shaped concave surface with its radius of curvature set larger than the radius of curvature of the second pocket surface.

Retainer for rolling bearing

A surface shape evaluation method for a spherical body comprising the steps of: providing a support hole having a smaller diameter than the spherical body and having a curved bearing surface formed on its opening to have a curvature substantially equal to the curvature of the surface of the spherical body, providing a rotation drive arm for transmitting only a rotation component to the spherical body, providing a vibration sensor having a probe with a flat tip end, rotating the spherical body on a predetermined center axis and on the opening, such that one portion in the radial direction of the spherical body comes into contact with the curved bearing surface while the portion opposite to the one portion in the radial direction of the spherical body comes into contact with the tip end of the rotation drive arm, abutting the flat tip end of the probe of the vibration sensor to a surface portion of the spherical body located on a hypothetical flat surface which is orthogonal to the center axis and passes through the central point of the spherical body to detect the surface shape from the surface portion as vibration amounts, from which the results are through a sampling process and an adding and averaging process in harmonization with rotation velocity of the spherical body, and a frequency analysis process are evaluated as a numerical value e.g. of at least displacement.

Surface shape evaluation method and device for spherical body

A cage for ball bearing having pockets 7 the inner surface of which comprises a spherical surface portion 15 and a pair of cylindrical surface portions 16 on the opposite sides of the spherical surface portion 15 connected continuously to the opposite edges of the spherical surface portion 15, the spherical surface portion 15 having a radius of curvature slightly larger than the radius of curvature of the rolling contact surface of the balls to be held in the pockets 7, wherein the area of the spherical surface portion 15 in sliding contact with the rolling surface of the balls is decreased to smoothly supply the pockets 7 with lubricant to decrease the cage sound caused due to friction.

Cage for ball bearing

In a rolling bearing including an inner race; an outer race; a plurality of rolling elements rollingly arranged between the inner race and the outer race; and a cage holding the rolling elements, the cage has an annular shape and a plurality of pockets which are formed at plural positions in a circumferential direction of the cage, in which each of the pockets has an opening peripheral portion which is curved to a direction of increasing a distance from a center of the rolling elements. The opening peripheral portion forms a chamfered face or a convex face. The rolling bearing can sufficiently ensure the lubrication of sliding contact portions between the cage and rolling elements so that vibrations and noises of the rolling bearing are lowered.

Cage for a rolling bearing

A rolling bearing unit having undulation on the rolling surfaces of the rolling elements where the total value of the wave components having an even number of waves per circumference is smaller than the total value of the wave components having an odd number of waves per circumference, or having undulation on the inner ring raceway and outer ring raceway, where the undulation on at least one of the raceway is conditioned such that the maximum waviness amplitude among (nZ), (nZ+1) and (nZ -1) waves per circumference is smaller than the maximum waviness amplitude among (nZ+2) and more waves per circumference, where n is a positive integer and Z is the number of rolling elements, thereby making it possible to obtain a low-cost, high-performance rolling bearing in which the vibration characteristics of the rolling bearing are improved without having to increase the precision required for manufacturing the rolling elements and inner ring raceway and outer ring raceways.

Rolling bearing unit

Growing community of inventors

Fujisawa, Japan

Banda Noda