| 摘要 |
PROBLEM TO BE SOLVED: To suppress gas to flow out to an outside, and hold a suitable bearing performance by forming a labyrinth bulk head part clearance smaller than an air pad part clearance, in a bearing clearance between a moving body and a fixing body. SOLUTION: Gas supplied to an air pad 9 by passing a supplying path 10 is exhausted to an atmosphere opening groove 7 after passing, and nearly all of it is exhausted to the atmosphere through an atmosphere opening piping 12. Few gas which is not exhausted, is exhausted from a vacuum seal groove 8 to a vacuum pump 13 through an exhaust piping 11 by passing an inside labyrinth bulk head part clearance 3. The rest of gas which is not exhausted therein is exhausted into a vacuum chamber by passing an outside labyrinth bulk head part clearance 4. A thin film 6 is formed on each labyrinth bulk head part, and the clearances 3, 4 are smaller than an air pad part clearance 5. A suitable bearing performance is held without changing the air pad part clearance 5 more than a conventional size, and a quantity of gas flow to the vacuum chamber is suppressed few.
|
