Claims
- 1. In an air control device including a body, an air passage formed in said body, a throttle valve disposed in said air passage for controlling an air quantity flowing in said air passage, a throttle shaft for mounting said throttle valve and extending across said air passage, and a pair of first and second ball bearings mounted in said body for rotatably supporting said throttle shaft, wherein an inner ring of at least one of said bearings is engaged by clearance fit with said throttle shaft; the improvement wherein:
- a surface of said throttle shaft is treated by a low-temperature salt bath nitriding process to form a nitrogen dispersing layer on said surface and a nitride layer formed on said nitrogen dispersing layer.
- 2. The air control device as defined in claim 1, wherein said surface is treated by said low-temperature salt bath nitriding process to further form an oxide film layer on said nitride layer.
Priority Claims (2)
Number |
Date |
Country |
Kind |
63-160487 |
Dec 1988 |
JPX |
|
1-97580 |
Aug 1989 |
JPX |
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Parent Case Info
This is a divisional of co-pending application Ser. No. 432,913 filed on Nov. 7, 1989 now U.S. Pat. No. 4,935,452.
US Referenced Citations (5)
Divisions (1)
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Number |
Date |
Country |
Parent |
432913 |
Nov 1989 |
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