JPH0635737U - Vacuum seal structure of shaft - Google Patents

Abstract

(57) [Abstract] [Purpose] To provide a vacuum sealing structure for a shaft, which is intended to extend the service life of a packing for vacuum sealing and to obtain a high vacuum sealing effect. A packing holder 20 having a shaft 2 which is rotationally driven and reciprocally linearly driven penetrates is attached to a vacuum container 4, and packings 22a to 22 are provided on an inner peripheral portion of the packing holder 20.
It contains c. A ring-shaped grease reservoir 26 is provided inside the packing holder 20 between the packings 22a and 22b, and the vacuum grease 28 is filled therein. In addition, a ring-shaped vacuum exhaust groove 30 that is evacuated to a vacuum is provided on the inner peripheral portion of the packing holder 20 and between the packings 22b and 22c.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a vacuum seal structure of a portion of a vacuum device such as an ion implantation device or a thin film forming device, in which a shaft used for transmitting power from the atmospheric pressure side into a vacuum container penetrates the vacuum container.

[0002]

[Prior art]

 FIG. 2 shows a conventional example of this type of vacuum seal structure. A shaft 2 penetrates a vacuum container 4 which is evacuated to a vacuum by a vacuum exhaust device (not shown). In this example, the shaft 2 is for transmitting power from the atmospheric pressure side to the inside of the vacuum vessel 4, and the drive source 6 is connected to the end portion on the atmospheric pressure side. In this example, a transfer arm 8 for transferring the wafer 9 is attached. The shaft 2 is driven by a drive source 6 to reciprocally rotate as indicated by arrow A and linearly reciprocate in the axial direction as indicated by arrow B, whereby the transfer arm 8 is swung and moved up and down in the vacuum container 4. .

The vacuum seal structure of the portion where the shaft 2 penetrates the vacuum container 4 is as follows. That is, the packing holder 10 through which the shaft 2 penetrates is attached to the vacuum container 4, and two packings 12 are housed inside the packing holder 10 in this example, whereby the shaft 2 is vacuum-sealed. . A vacuum seal is provided between the packing holder 10 and the vacuum container 4 by a packing 14. These packings 12, 14 are, for example, O-rings.

[0004]

[Problems to be solved by the device]

 Since the shaft 2 is driven as described above, the packing 12 is lubricated by applying vacuum grease (grease that does not easily evaporate even in a vacuum), but the packing 12 is simply coated with vacuum grease. As a result, the amount of grease applied cannot be sufficiently taken, and therefore the lubrication between the packing 12 and the shaft 2 is not sufficiently performed, so that the packing 12 is likely to wear and cause a vacuum leak, and the life of the packing 12 is shortened. There is the problem of being short.

Moreover, in the above structure, water molecules and the like attached to the shaft 2 on the atmospheric pressure side easily pass through the two packings 12 in order and enter the vacuum container 4 due to the reciprocating linear motion of the shaft 2 as described above. Therefore, there is also a problem that a high vacuum sealing effect cannot be obtained.

[0006] Therefore, the main object of the present invention is to provide a vacuum seal structure for a shaft, which is intended to prolong the service life of a packing for vacuum seal and to obtain a high true air seal effect.

[0007]

[Means for Solving the Problems]

 In order to achieve the above object, the vacuum seal structure of the present invention is a structure for holding a packing in a structure in which a shaft which is rotationally driven and reciprocally linearly driven penetrates a vacuum container to form a vacuum seal. A through packing holder is attached to the vacuum container, and the first, second, and third packings counted from the inside of the vacuum container are housed in the inner peripheral portion of the packing holder. A ring-shaped grease reservoir is provided between the first and second packings to fill the vacuum grease, and there is an empty space between the second and third packings on the inner circumference of the packing holder. It is characterized in that a ring-shaped vacuum exhaust groove for exhausting the gas is provided.

[0008]

[Action]

 According to the above structure, the grease reservoir is filled with the vacuum grease, and the vacuum grease spreads to the first to third packing parts as the shaft reciprocates linearly. This ensures sufficient lubrication between the shaft and the first to third packings. As a result, the wear of each packing is reduced, and the life of the packing can be extended.

Moreover, since the vacuum exhaust groove is evacuated to a vacuum, even if water molecules or the like attached to the shaft come in from the atmospheric pressure side over the third packing, the water molecules or the like are discharged from the vacuum exhaust groove. It can be discharged to the outside to prevent it from entering the vacuum vessel. As a result, a high vacuum sealing effect can be obtained.

[0010]

【Example】

 FIG. 1 is a sectional view showing a vacuum seal structure according to an embodiment of the present invention. The same or corresponding portions as those of the conventional example shown in FIG. 2 are designated by the same reference numerals, and in the following, differences from the conventional example will be mainly described.

In this embodiment, the packing holder 20 through which the shaft 2 passes as described above is attached to the vacuum container 4 as described above, and the inner circumference of the packing holder 20 is first counted from the inside of the vacuum container 4. The second and third packings 22a, 22b and 22c are housed and the shaft 2 is vacuum-sealed by the packings 22a to 22c. A vacuum seal is provided between the packing holder 20 and the vacuum container 4 by a packing 24. These packings 22a to 22c and 24 are, for example, O-rings.

A ring-shaped grease reservoir 26 is provided on the inner peripheral portion of the packing holder 20 between the first and second packings 22a and 22b, and the vacuum grease 28 is filled therein. The vacuum grease 28 is a grease that does not easily evaporate even in a vacuum, and an example of such a grease is Fombling Wreath (trade name).

Further, a ring-shaped vacuum exhaust groove 30 that is evacuated to a vacuum is provided on the inner peripheral portion of the packing holder 20 and between the second and third packings 22b and 22c. In this embodiment, the vacuum exhaust groove 30 is evacuated to a vacuum by a vacuum exhaust device (not shown) via the communication hole 32 in the packing holder 20, the connector 34 attached to the packing holder 20, and the pipe 36. The vacuum exhaust groove 30 does not need to be evacuated as high as the degree of vacuum in the vacuum container 4 (for example, about 1 × 10 ⁻⁷ to 1 × 10 ⁻⁸ Torr), and is lower than that, for example, about 10 ⁻¹ Torr. It can be evacuated to.

According to the above-mentioned structure, the grease reservoir 26 is filled with the vacuum grease 28, and the vacuum grease 28 is applied to the packings 22a to 22c as the shaft 2 reciprocates linearly as shown by the arrow B. The vacuum grease 28 sufficiently expands the lubrication between the shaft 2 and the packings 22a to 22c. As a result, the wear of the packings 22a to 22c is reduced, and the service life thereof can be extended.

Moreover, since the vacuum exhaust groove 30 is exhausted to a vacuum, even if water molecules or the like attached to the shaft 2 enter from the atmospheric pressure side over the packing 22c, the water molecules or the like are exhausted to the vacuum exhaust groove 30. Can be discharged to the outside to prevent it from entering the vacuum container 4. Further, even if a minute vacuum leak from the packing 22c due to a mechanical assembly error or the like is caused, the influence can be prevented from reaching the inside of the vacuum container 4 by the vacuum exhaust groove 30. As a result, according to this vacuum seal structure, a high vacuum seal effect can be obtained. Therefore, for example, it becomes easy to maintain a high degree of vacuum in the vacuum container 4 that is evacuated to a high vacuum.

The packing holder 20 may be further provided with packings other than the first to third packings 22a to 22c, if necessary.

Further, the shaft 2 does not necessarily have to be reciprocally rotationally driven as in the above example, but may be one that is rotationally driven in one direction.

Further, what is connected to the shaft 2 does not necessarily have to be the drive source 6 and the transfer arm 8 as in the above example, and may be another one.

[0019]

[Effect of device]

 As described above, according to the present invention, the vacuum grease filled in the grease reservoir sufficiently lubricates the shaft and each packing, so that each packing is less worn and its life is extended. Can be achieved.

Moreover, the vacuum exhaust groove can discharge water molecules and the like coming from the atmospheric pressure side to the outside and prevent them from entering the vacuum container, so that a high vacuum sealing effect can be obtained. You can

[Brief description of drawings]

FIG. 1 is a sectional view showing a vacuum seal structure according to an embodiment of the present invention.

FIG. 2 is a sectional view showing an example of a conventional vacuum seal structure.

[Explanation of symbols]

 2 shafts 4 vacuum container 20 packing holder 22a first packing 22b second packing 22c third packing 26 grease reservoir 28 vacuum grease 30 vacuum exhaust groove

Claims (1)

[Scope of utility model registration request] 1. In a structure in which a shaft that is rotationally driven and reciprocally linearly driven vacuum seals a portion that penetrates the vacuum container, a packing holder that holds a packing and that the shaft penetrates is attached to the vacuum container. , The first and second inner circumferences of this packing holder are counted from the inside of the vacuum container.
And a third packing, the ring-shaped grease reservoir is provided between the first and second packings on the inner circumference of the packing holder, and the vacuum grease is filled therein. Inner circumference of the second and third
A vacuum seal structure for the shaft, characterized in that a ring-shaped vacuum exhaust groove that is evacuated to vacuum is provided between the packings.