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

Patent metadata

Field	Value
Publication number	US-10048214-B2
Application number	US-201214241043-A
Country	US
Kind code	B2
Filing date	Jul 27, 2012
Priority date	Aug 26, 2011
Publication date	Aug 14, 2018
Grant date	Aug 14, 2018

Abstract

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.

First claim

The invention claimed is:

1. An inspection method of a rolling element made of ceramics, comprising the steps of:
projecting an X-ray from a light source to said rolling element, said light source being rotated relatively around said rolling element while said X-ray is simultaneously projected to an entire region of said rolling element facing said light source;
detecting said X-ray passing through said rolling element with a 2D detector, while said light source is rotated relatively around said rolling element;
calculating data of said detected X-ray to generate a 3D image, data of said X-ray for one circuit around said rolling element being calculated to generate said 3D image; and
based on said generated 3D image, detecting an internal defect in said rolling element that is a metal inclusion or a hole,
wherein during the steps of projecting an X-ray and detecting said X-ray, the light source and the 2D detector rotate around said rolling element while maintaining a positional relationship relative to each other; and
wherein the data of said detected X-ray calculated to generate the 3D image includes data of X-rays transmitted through the outer edge portion of the rolling element.

2. The inspection method of a rolling element according to claim 1 , wherein said X-ray is projected from said light source having a focal point size less than or equal to 10 μm, at said step of projecting an X-ray.

3. The inspection method of a rolling element according to claim 1 , wherein said X-ray spreading conically from said light source is projected to said rolling element, at said step of projecting an X-ray.

4. The inspection method of a rolling element according to claim 1 , wherein said ceramics has silicon nitride or sialon as a main component.

5. The inspection method of a rolling element according to claim 1 , wherein a defect of at least 20 μm in size is detected at said step of detecting a defect.

6. A manufacturing method of a rolling element comprising the steps of:
producing a rolling element made of ceramics, and
inspecting said rolling element,
said rolling element being inspected by the inspection method of a rolling element defined in claim 1 , at said step of inspecting a rolling element.

7. A rolling element manufactured by the manufacturing method of a rolling element defined in claim 6 .

8. The inspection method of a rolling element according to claim 1 , wherein the detecting step includes detecting a defect in said rolling element based on said 3D image that would not be detected based on a 2D image generated from data of said X-ray from any single position along the circuit around said rolling element.

Assignees

• Tanaka Yutaka
• Muramatsu Katsutoshi
• Suzuki Hiroaki
• Ito Daichi
• Nozaki Masayuki
• Ntn Toyo Bearing Co Ltd

Inventors

• Tanaka Yutaka
• Muramatsu Katsutoshi
• Suzuki Hiroaki
• Ito Daichi
• Nozaki Masayuki

Classifications

• G01N2223/646

  flaws, defects · CPC title

• F16C33/30

  Parts of ball or roller bearings · CPC title

• G01N23/083

  the radiation being X-rays · CPC title

• G01M13/04

  Bearings · CPC title

• G01N23/04 Primary

  and forming images of the material · CPC title