JPH0449813Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Field of Application] This invention relates to an ultra-high vacuum shaft seal between a shaft and a bellows flange of a vacuum device such as an electron microscope in which the shaft moves.

[Conventional technology]

In vacuum equipment such as electron microscopes, ultra-high vacuum is maintained by bellows in equipment whose shafts move, such as movable apertures and vacuum valves. FIG. 4 is a sectional view of a conventional ultra-high vacuum shaft seal. In the figure, 1
is a bellows, one end of which is attached to the mounting flange 2, and the other end of which is attached to the bellows flange 3. The bellows flange 3 has an O-ring 6 in a triangular groove 5 formed between the bellows flange 3 and the ring 4.
A presser plate 10 is fixed to the shaft 7 by tightening screws 11 with a retaining ring 9 fitted in a circumferential groove 8 of the shaft 7 in between.

In the above configuration, the bellows flange 3 is fixed to the shaft 7 via the retaining ring 9, and since the O-ring 6 is interposed between the bellows flange 3 and the shaft 7, a sealed state is maintained. When the shaft 7 moves in the axial direction, the amount of movement is absorbed by the bellows 1, and the ultra-high vacuum state is maintained.

[Problem that the invention attempts to solve]

However, in the conventional ultra-high vacuum shaft seal as described above, the bellows flange 3 and the shaft 7 are not completely fixed, so when the shaft 7 moves, there is a slight movement, which causes the vacuum to leak from the seal. There was a problem that leakage occurred.

This idea was developed to solve the above problem.By tightening the shaft with a chuck, the bellows flange and shaft are completely fixed in both the axial and rotational directions, so that even if the shaft moves, the shaft will not move against the bellows flange. The purpose is to provide an ultra-high vacuum shaft seal that does not move and does not cause vacuum leaks.

[Means for solving problems]

This invention includes a bellows flange attached to the shaft via an O-ring, a bellows attached to the bellows flange so as to cover the shaft, and a bellows fitted to the shaft so as to regulate the axial position of the bellows flange. A retaining ring that fits together, a chuck provided on the opposite side of the bellows flange of the retaining ring, and a retaining plate that presses the retaining ring so as to sandwich the retaining ring between the chuck and the bellows flange, the chuck and the retaining plate This ultra-high vacuum shaft seal is characterized in that it has tapered portions that come into contact with each other, and the chuck is pressed against a holding plate to tighten the shaft.

The shaft is moved with a bellows flange attached, and the O-ring is inserted into a triangular groove formed between the bellows flange and the ring or a square groove formed in the bellows flange to form a seal between the two. be done. Preferably, the retaining ring fits into a groove provided in the circumferential direction of the shaft, but other structures may be used. It is preferable that the chuck has a tapered portion and is tightened by passing the shaft through a hollow portion of a fastening piece divided in the axial direction by a slot, but other structures may also be used. It is preferable that the holding plate has a tapered part corresponding to the tapered part of the chuck, and is attached to the bellows flange with screws so that the tapered part holds the chuck in the axial and central direction. It can be anything.

The present invention is suitable for ultra-high vacuum shaft seals such as movable apertures and vacuum valves in electron microscopes, but can also be applied to other vacuum devices.

[Effect]

Attach the bellows flange to the shaft via an O-ring, install the bellows to cover the shaft, fit a retaining ring onto the shaft to restrict the axial position of the bellows flange, and attach a chuck on the opposite side of the retaining shaft. Attach it, stack the presser plate on the bellows flange, bring the tapered parts of each part into contact, and tighten. As a result, the holding plate presses the chuck to tighten the shaft, and also secures the retaining ring between the bellows flange and the chuck.

In this state, the bellows flange and the shaft are completely fixed in the axial and rotational direction, so no vacuum leak occurs even if the shaft moves.

〔Example〕

This invention will be explained below with reference to embodiments of the drawings. FIG. 1 is a sectional view showing an embodiment of this invention.
FIG. 2 is a perspective view of the chuck, and the same reference numerals as in FIG. 4 indicate the same or corresponding parts.

In the figure, 12 is a chuck, and the tapered part 13
The shaft 7 is passed through the hollow part 16 of the clamping piece 15 divided in the axial direction by the slot 14, and the shaft 7 is tightened by the clamping piece 15. It is arranged to sandwich 9. Presser plate 1
0 has a tapered portion 17 corresponding to the tapered portion 13. The other configurations are the same as in FIG. 4.

In the above configuration, the chuck 12 is attached to the shaft 7 and the retaining ring 9 is sandwiched between the chuck 12 and the bellows flange 3. Lay it on the flange 3 and tighten and fix it with the screws 11. As a result, the tapered portion 13 of the chuck 12 is pushed in the direction of the axis and the center, and the tightening piece 15 of the chuck 12 tightens the shaft 7 and also holds the retaining ring 9 between it and the bellows flange 3. In this way, the bellows flange 3 and the shaft 7 are completely fixed both in the axial direction and the rotational direction, and even if the shaft 7 moves, the shaft 7 does not move relative to the bellows flange 3, and the sealing part by the O-ring 6 is stable, and the vacuum No leakage occurs.

FIG. 3 is a partial sectional view showing another embodiment, in which the O-ring 6 is inserted into a square groove 18 formed in the bellows flange 3.
It is a piston type seal.

[Effect of idea]

According to this invention, since the shaft is tightened with a chuck, the bellows flange and shaft are completely fixed in both the axial and rotational directions, and even if the shaft moves, the shaft will not move relative to the bellows flange. Therefore, the sealing part is stable and vacuum leakage does not occur.

[Brief explanation of the drawing]

Fig. 1 is a sectional view of one embodiment of this invention, Fig. 2 is a perspective view of the chuck, Fig. 3 is a sectional view of a part of another embodiment, and Fig. 4 is a conventional ultra-high vacuum shaft seal. FIG. In each figure, the same reference numerals indicate the same or equivalent parts, 1 is a bellows, 3 is a bellows flange, 6 is an O-ring, 7 is a shaft, 9 is a stop shaft, 10 is a presser plate, 1
2 is a chuck and 14 is a slot.

Claims (1)

[Claims for Utility Model Registration] (1) A bellows flange attached to the shaft via an O-ring, a bellows attached to the bellows flange so as to cover the shaft, and a position of the bellows flange in the axial direction. A retaining ring that fits on the shaft so as to restrict the retaining ring, a chuck provided on the opposite side of the bellows flange of the retaining ring, and a holding plate that presses the retaining ring so as to sandwich the retaining ring between the chuck and the bellows flange. An ultra-high vacuum shaft seal, characterized in that the chuck and the holding plate have tapered portions that come into contact with each other, and the chuck is pressed by the holding plate to tighten the shaft. (2) The ultra-high vacuum shaft seal according to claim 1, wherein the O-ring is provided in a triangular groove formed between the bellows flange and the ring or in a square groove formed in the bellows flange. (3) The ultra-high vacuum shaft seal according to claim 1 or 2, wherein the retaining ring fits into a groove provided in the shaft. (4) The ultra-high vacuum according to any one of claims 1 to 3, in which the chuck has a tapered portion and fastening pieces divided in the axial direction by slots. shaft seal. (5) Claims 1 to 4 of the utility model registration in which the holding plate is attached to the bellows flange with screws
The ultra-high vacuum shaft seal described in any of paragraphs.