Back to results
US 5,181,691 AGranted
Mechanical part made of ceramics
AssigneeNgk Spark Plug Co., Ltd.
InventorsMasato Taniguchi, Juzo Yagi, Hiroshi Takeda
Life of this patent
Estimating the term…
Abstract
A mechanical part has a contact surface for movement on a mating surface. The contact surface is first rough ground by using a grinding wheel of a grain size, for example, equal to or smaller than #200 and then barrel finished or buffed so as to have such a profile that is roughness spacing ranges from 5 to 100 .mu.m and more than half of its peaks are smoothly rounded.
Claims1
A ball valve comprising:
- a seal ring having a fluid passage and a part-spherical contact surface;
- and
- a ceramic main body rotatably received in said seal ring and having a part-spherical ceramic contact surface in sliding contact with the contact surface of said seal ring for controlling the opening and closing of said fluid passage;
- said ceramic contact surface having a profile with a roughness spacing which ranges from 5 to 100 .mu.m and with more than half of its peaks smoothly rounded, whereby said ceramic contact surface is capable of retaining lubricant on said ceramic contact surface while providing a relatively large contact surface area.
1 more element
Dependencies are inferred from the claim text.