Ntn Corporation

Tomoaki Terada

Kenichi Ichikawa

Hitoshi Murakami

Toshihiko Matsushima

Masuhisa Yoshida

Fumio Oba

The straightness and parallelism of a track surface on which rollers roll are measured within a range 'L' as a range for measuring the straightness and parallelism. The range 'L' is a range such that L&#x2267;0.8&#xd7;L when a roller length is &#x201c;L&#x201d;. When the dimension from the corner P of the flange on the inner diameter side to the starting point of the range &#x201c;L&#x201d; is &#x201c;L&#x201d;, the dimension &#x201c;L&#x201d; is ranged such that 0.8 mm&#x2266;L&#x2266;2 mm. In this range, the straightness of the track surface of the outer ring in the axial direction is not more than 0.008 mm and the parallelism thereof is not more than 0.015 mm.

Outer ring, drawn cup needle roller bearing, drawn cup needle roller bearing structured body, piston pin supporting structure of engine, crankshaft supporting structure of engine, and 2-cycle engine

The needle roller bearing B in this embodiment comprises a cage 1 having a plurality of elongated window-shaped pockets 1a formed therein at predetermined circumferential intervals, and a plurality of needle rollers 2 rollably received and held in the pockets 1a. The four corners A of each pocket 1a of the cage 1 are provided with relief portions 1an4 each having a circumferentially recessed arcuate peripheral wall surface. The circumferential dimension between the circumferential top 1a41 of the relief potion 1a4 and the pocket wall surface 1a1 is set with respect to the diameter Dw of the needle rollers 2 such that 0.01.ltoreq.h/Dw.ltoreq.0.2. The provision of the relief portions 1a4 at the corners A of each pocket 1a of the cage 1 permits the relief portions 1a4 to serve as passageways for the lubricating oil.

Needle roller bearing

A roller bearing includes an outer ring having a raceway formed on its inner periphery, a plurality of rollers arranged along the raceway at predetermined intervals, and a solid lubricant filling the spaces between the adjacent rollers. The rollers and the solid lubricant form a one-piece body. The problems of large friction between rollers and the skewing of rollers are solved and it is possible to increase the load-bearing capacity of the bearing by using a large number of longer rollers.

Growing community of inventors

Iwata, Japan

Tomoaki Terada