Ntn Corporation

Masayuki Nozaki

Takashi Ito

Masaki Egami

Takuya Ishii

Katsutoshi Muramatsu

Daichi Ito

Shohei Nakamura

Yutaka Tanaka

Rei Mihara

Hiroaki Suzuki

Toyohiko Ota

Akira Okayasu

An inspection method of a rolling element includes the steps of: projecting an X-ray from a light source to a rolling element, detecting the X-ray passing through the rolling element by a detector, calculating data of the detected X-ray to form an image, and detecting a defect in the rolling element based on the image. At the step of projecting an X-ray, the light source rotates relatively around the rolling element while the X-ray is projected to an entire region of the rolling element facing the light source. At the step of forming an image, data of the X-ray for one circuit around the rolling element is calculated to generate the image.

Rolling element inspection method, rolling element manufacturing method, and rolling element

It is an object of the present invention to provide a cage that can be used in a cryogenic-temperature environment or a vacuum without providing the cage with a complicated construction and without performing special treatment and a bearing using the cage. A cage made of resin has an annular main body having a plurality of pocket portions radially penetrating the main body; and a plurality of pocket members, provided on the annular main body, which hold rolling elements of a rolling bearing. The main body is a molding of a first resin composition consisting of a first resin and a solid lubricant mixed therewith; and at least a rolling element-retaining surface of each of the pocket members is made of a second resin composition containing fluorocarbon resin as a main component thereof. The molding of the first resin composition has a tensile strength of not less than 30 MPa and a heat-resistant temperature of not less than 200&#xb0; C. The second resin composition is a fluorocarbon resin composition. The rolling bearing is constructed of an inner ring, an outer ring, the rolling elements interposed between the inner ring and the outer ring, and the cage. The rolling bearing is used for a turbopump, of a rocket engine, which uses a liquid fuel.

Resin-made cage and bearing

Growing community of inventors

Kuwana, Japan

Masayuki Nozaki