Ntn Corporation

Masao Fukuwaka

Takahiro Koremoto

Masahiro Muranaka

Hiroshi Kawamura

Motoharu Niki

Seiya Inoue

Takahiro Kanamoto

Tadahisa Suzuki

Tsutomu Mizutani

Yoshiaki Suzuki

Yoshio Kato

Tadaaki Maeda

A ball bearing for a pulley that is a component of a wrapping connector transmission device installed to an engine for an automobile. In the bearing, the depths of ball grooves formed in the inner ring and the outer ring of the ball bearing are set so that the risk rate of the ball being stranded on the shoulder becomes approximately the same for the inner ring and the outer ring under pure thrust load. Furthermore, the depth of the ball groove of the outer ring is set shallower than the depth of the ball groove of the inner ring. The depth of the ball groove of the outer ring is set in a range of 12-19% of the diameter of the ball.

Pulley ball bearing and pulley

A pulley which is brought into contact with a timing belt of an engine of automobile and a belt for driving auxiliary machinery, and a ball-bearing used for the same, wherein the radial internal clearance in the running state of a ball bearing is set to substantially 5 to 30 .mu.m, and grease to be sealed in said ball bearing is such that the base oil thereof is made a mixture of .alpha.-olefin oligomer and ester, the thickening agent thereof is made a mixture of an alicyclic urea compound and an aliphatic urea compound, the worked penetration thereof is roughly 240, and the base oil viscosity thereof is made 40 to 43 cSt at a temperature of 40.degree. C., whereby it is possible to suppress self-excited vibrations of a rolling element and to securely prevent the hoot sound from occurring. Furthermore, since grease used herein has superior characteristics in the high temperature durability, there is no worry about a lowering of the high temperature durability as in conventional pulleys in which low temperature grease of good low temperature characteristics is employed.

Pulley and ball bearing for pulleys

Idler pulley

A slight clearance S1 is formed between the inner surface of the outer ring 2b and the outer surface of the cage 2d. The size of this slight clearance S1 is such that it causes concomitant rotation of the cage 2d associated with the rotation of the outer ring 2b.

Rolling contact bearing

Growing community of inventors

Iwata, Japan

Masao Fukuwaka