JPH02134471A - Seal mechanism for introduction of linear power - Google Patents

Abstract

PURPOSE:To have a sealing mechanism for introduction of linear power with good airtightness and durability without causing contamination of vacuum atmosphere by using a twisted O-ring for a one to seal the shaft, and forming the bore of a casing retaining this twisted O-ring concentrical with the shaft. CONSTITUTION:Because the bore of a casing 3 at the back of a twisted O-ring 2 is formed cylindrical concentrical with the shaft 1, the O-ring 2 rolls between the shaft 1 and casing 3 with reciprocative motion of the shaft 1. Thus sealing is obtained. Because the friction mode of the shaft with O-ring is rolling friction, as well the friction force as the amount of wear can be lessened, which should prevent contamination of the atmosphere due to abrasion dust, resulting in prolongation of the life of sealing, and also the power supply to drive the shaft can remain with a minor capacity.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a sealing mechanism for introducing linear power into vacuum equipment such as dry etching equipment, sputtering equipment, and plasma CVD equipment.

[Conventional technology]

Conventionally, as a seal mechanism for introducing linear power using an O-ring, for example, the O-ring is fixed in a groove machined in a casing, as disclosed in Vacuum Technology (Author: Gen Horikoshi), pages 145 to 146, There was a method of introducing linear power while sealing the shaft and O-ring by sliding them. This sealing method for introducing linear power is described in many vacuum technology textbooks, and is widely used as a method for introducing linear power at low speeds.

[Problem to be solved by the invention]

In the above-mentioned conventional technology, since the shaft is linearly driven with two O-rings fixed in the grooves of the casing, sliding friction occurs between the O-rings and the shaft, resulting in large frictional force and significant wear. Therefore, there are disadvantages such as a short seal life, contamination of the vacuum atmosphere by abrasion powder, and a need for a large driving force due to the large frictional force. Furthermore, as a means of reducing these frictional forces and preventing wear, there is a method of using low vapor pressure grease or oil as a lubricant.

However, this method has the problem of contaminating the vacuum atmosphere due to the evaporation of grease or oil, and furthermore, the gas adsorbed by the grease or oil on the surface of the shaft is re-emitted in the vacuum, and the intermediate chamber is evacuated. However, there was a problem in that the inflow of gas could not be eliminated.

SUMMARY OF THE INVENTION An object of the present invention is to provide a sealing mechanism for introducing linear power that has good airtightness and durability without contaminating the vacuum atmosphere.

[Means to solve the problem]

The above object is achieved by using a twisted O-ring as the shaft sealing O-ring in the linear power introduction seal mechanism, and making the inner diameter of the casing that holds the twisted O-ring concentric with the shaft.

[Effect]

By configuring the sealing element in this way, it is possible to
As the O-ring moves, it rolls around the outer periphery of the shaft and the inner periphery of the casing.

That is, the form of friction between the shaft and the O-ring is not sliding friction but rolling friction, which can lower the frictional force and reduce the amount of wear.

〔Example〕

Embodiments of the present invention will be described below with reference to the drawings.

Figures 1 and 2 show the first embodiment of the linear power introduction mechanism of the present invention, and in these figures, 1 is a shaft that moves reciprocatingly, 2 is a torsion O-ring, and 3 is an O-ring that holds it. It is a casing that In addition, in the figure, the upper side is the low pressure side and the lower side is the high pressure side, and in the case of FIG. 1, an example is shown in which the shaft moves downward in the figure.

The torsional O-ring 2 is made by first cutting the - side as shown in Fig. 2(a), or by cutting a round rubber to the required length and cutting one end as shown in Fig. 2(b). It is made by twisting it half a turn to once, and then welding or gluing it again as shown in Figure 2 (Q). In addition, in the figure, I-1 shows a cut surface, and 7 shows a twisting direction.

This twisted O-ring is attached to the casing 3 on the back side.
Since the inner surface of the shaft 1 is machined into a concentric cylindrical shape, the shaft 1
The reciprocating movement and rolling movement between the shaft 1 and the casing 3 perform sealing.

Note that the number 4 prevents the O-ring 2 from being removed.

In this way, twist the O-ring to make it an O-ring.

By making the inner diameter of the casing on the back cylindrical and concentric with the shaft, the friction between the shaft and the torsional O-ring becomes rolling friction rather than flat friction as with conventional fixed O-rings, which reduces the frictional force. As a result, contamination of the atmosphere by abrasion particles can be prevented, the life of the seal can be extended, and the power source for driving the shaft can also be of small capacity.

FIG. 3 shows a second embodiment of the linear power introduction mechanism of the present invention. In this figure, the same numbers as in FIG. 1 indicate the same parts. In the first embodiment shown in FIG. 1, when the differential pressure between the low pressure side and the high pressure side is large, the torsion O-ring It may be pulled toward the lower pressure side due to differential pressure.

The second embodiment deals with the case where the pressure difference between the low pressure side and the high pressure side is large. That is, in this embodiment, a plurality of torsion O-rings are installed on the shaft 1, and the angle of 8,9°10
, install it, provide an exhaust port 11 in the casing for the space 16° 17 between each O-ring, and vacuum evacuate 12 using an independent exhaust pump, so that the pressure is gradually reduced from the high pressure side to the low pressure side. This is what I did. In this embodiment, the same effect as the above-described embodiment can be obtained, and an even higher pressure difference can be sealed.

FIG. 4 shows a third embodiment of the seal mechanism for introducing linear power according to the present invention. In this embodiment, a normal O-ring 14 is attached to the O-ring on the high-pressure side, and a groove 15 is machined so that the O-ring can be fixed to the casing 3 to create sliding friction. A torsion O-ring 13 is attached to the low pressure side, and an exhaust port 11 is provided in the casing 3 to create a structure in which the space between the fixed O-ring 14 and the torsion O-ring 13 can be evacuated 12 using an exhaust pump. ing.

As a result, the differential pressure between the low pressure side and the high pressure side is reduced by the fixed O-ring 1.
4 performs sealing, and abrasion powder generated by the friction between the shaft 1 and the fixing O-ring 14 is sealed by the torsion O-ring 13 and is discharged from the exhaust port 11 by the exhaust pump, so that the atmosphere on the low pressure side A good seal can be achieved without contaminating the seal, and the number of torsion O-rings in the sealing mechanism shown in the second embodiment shown in FIG. 3 can be reduced.

In a fourth embodiment of the present invention, the fixed O-ring 15 shown in FIG. 4 is coated with low vapor pressure grease or oil. In this case, the stroke of the shaft is arranged so that grease or oil transferred from the fixed O-ring 14 to the shaft does not come into contact with the twisted O-ring 13 due to the forward movement of the shaft.

As a result, the gas that is adsorbed to the grease or oil on the surface of the shaft 1 and re-released in the space 18 is removed from the exhaust port 11 by the exhaust pump while being sealed by the torsion ring 13.
On the other hand, since the fixed O-ring can reduce both the frictional force and the amount of wear by using a lubricant, it is possible to obtain a good sealing mechanism that has a long life and does not contaminate the low-pressure atmosphere.

As described above, according to the embodiment of the present invention, the sealing element of the sealing mechanism for introducing linear power is a torsion O-ring capable of rolling motion, thereby reducing frictional force.

It is possible to provide a long-life sealing mechanism with less wear.

〔Effect of the invention〕

As described above, according to the present invention, it is possible to reduce the frictional force and amount of wear between the shaft and the sealing O-ring, and to perform good sealing, so that a clean vacuum atmosphere can be obtained.
Furthermore, it becomes possible to reduce the capacity of the drive source.

[Brief explanation of the drawing]

FIG. 1 is a sectional view showing a first embodiment of the sealing mechanism of the present invention, FIGS. The figures are sectional views showing other embodiments of the sealing mechanism of the present invention. DESCRIPTION OF SYMBOLS 1... Shaft, 2, 8, 9, 10, 13... Twisted O-ring, 3... Casing, 11... Exhaust port, 14...
・・Fixed string 1 Figure Y 3 Figure (艮) 12 Ward 1... Shaft 2- θy7" 310. Casing 4... Stop 0 4th figure Takanoj = I return work

Claims (1)

[Claims] 1. In a linear power introduction seal mechanism that is composed of a linearly moving shaft, an elastomer O-ring that seals the shaft, and a casing that holds the O-ring, and that transmits linear power from a high-pressure part to a low-pressure part or from a low-pressure part to a high-pressure part, The elastomer O-ring is made by cutting one side of the O-ring or cutting a round rubber to the required length, twisting one end and welding or bonding again to form a twisted O-ring, and make the inner diameter of the casing facing the shaft into a cylinder concentric with the shaft. A seal mechanism for introducing linear power.