JPH023044B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a non-contact sealing device used for supplying high-pressure gas or vacuum pressure to a high-speed rotating body.

As an example, a case will be described in which vacuum pressure is supplied to a high-speed rotating body. Usually, a labyrinth seal, which is a type of non-contact seal, is used for such applications.

In FIGS. 1 and 2, reference numeral 1 denotes a rotating shaft having a flange 2 at its tip, which is rotatably supported by a bearing (not shown) and rotationally driven by a motor or the like. 3 has a groove 4 formed concentrically on one surface and a groove 5 formed radially from the center of rotation on the other surface, and a hole 6 penetrating both grooves 4 and 5, as shown in the figure. This is a vacuum chuck fixed to the flange 2 with bolts or the like. 7 is a hub fixed to the vacuum chuck 3 with bolts 8. The bolt 8 has a hexagonal hole 9 and a through hole 10 for tightening the bolt. 11 is a radial ball bearing, an outer ring 12 is press-fitted into the hub 7, and a seal retainer 14 is press-fitted into the inner ring 13. 15 is a sealing member, and the radial ball bearing 1
The set screw 27 after the outer ring 12 of No. 1 is press-fitted into the hub 7
It is fixed to the seal retainer 14 by. This seal member 115 constitutes a labyrinth seal by its convex portion 16 and the concave portion 17 of the hub 7.

18 is a lever having an air circulation hole 19, and a shaft 20 fixed to the fuselage (not shown) is the fulcrum and 12 arrow A
It is rotatably supported in directions 1 and B, and a rubber lining 28 is provided at its tip to improve close contact with the seal retainer 14.

21 is a tube that connects the lever 18 and a vacuum source (not shown). A workpiece 22 is placed on the vacuum chuck 3 with its center portion positioned by the outer periphery of the hub 7. Of course, when attaching and detaching the workpiece 22 to and from the vacuum chuck 3, the vacuum pressure is turned off and the lever 18 is rotated in the direction A.

When vacuum pressure is applied in FIG. 1, air is exhausted through the path shown by line C, and the workpiece 22 is fixed to the vacuum chuck 3 by suction. In addition, external air flows through the path shown by line D in FIG.
4 and the inner ring 13 into the interior 26 through the gap 25. The amount of inflow is determined by the gap between the shapes of the protrusions 16 and recesses 17 that constitute the labyrinth seal 23, and when the amount of inflow is large, the vacuum pressure in the interior 26 becomes weaker, and a sufficiently strong force is applied to the workpiece 22.
cannot be absorbed. In that case, a vacuum source with high exhaust capacity is required. After the workpiece 22 is attracted to the vacuum chuck 3, when the shaft 1 is rotated by a motor or the like, the seal retainer 14 is attached to the radial ball bearing 11.
The lever 18 is pulled by the vacuum pressure inside 26, and the rubber lining 28 is pressed against the seal retainer 14.Furthermore, since the rubber lining has a large coefficient of friction, the rubber lining 28 and the seal retainer 14 are No slipping occurs. In some cases, the lever 18 may be biased by a spring or the like to press the rubber lining 28 against the seal retainer 14. In the above conventional example, the labyrinth seal 23 is
Since the labyrinth seal 23 is configured separately from the labyrinth seal 23, it is not possible to increase the mounting accuracy of the labyrinth seal 23.
The seal gap is usually about 0.1 to 0.05 .mu.m at the smallest, and the leakage of vacuum pressure is large, resulting in low efficiency. Furthermore, in order to increase efficiency, it is necessary to overlap several aperture sections and expansion sections, making it impossible to construct a compact structure. Further, in order to strengthen the internal vacuum pressure with a seal that has a large pressure leak, a vacuum source such as a vacuum pump with high exhaust capacity is required, which is disadvantageous in terms of cost. Furthermore, if the bearing 11 is used in a state where there is a large amount of leakage, the loss of grease flowing out inside the seal 24 of the bearing 11 will increase, and a large amount of external dust will also enter between the inner ring 13, outer ring 12, and balls 29, and the life of the bearing 11 will be significantly shortened. As a result, it was necessary to replace it frequently.

In particular, when high pressure is supplied, the pressure difference increases and the leakage flow rate also increases, resulting in a greater loss of grease flowing out.

As mentioned above, the conventional devices had many drawbacks.

The present invention aims to solve such problems, and one embodiment thereof is shown in FIGS. 3 to 6.

Elements that are the same as those in the conventional example will be described using the same numbers. In FIG. 3, FIG. 4, FIG. 5, and FIG. 6, parts that are not otherwise specified are the same as those of the prior art.

The radial ball bearing 11 is press-fitted into the hole 40 of the hub 7 as in the conventional case, but the end of the outer ring 12 is pressed into contact with the stepped portion 41 of the hub 7 via an annular seal member 42 shown in FIG. ing. 50 is a notch formed in the hole 40 of the hub 7. The sealing member 42 is formed with a sealing surface 44 that faces the lower end surface 43 of the inner ring 13 in a non-contact manner, and the surfaces 43 and 44 constitute a non-contact seal 46. 51 is a notch formed in the seal member 42. When vacuum pressure is applied to the hole 19, the external air flows through the path shown by the line Ea in FIG.
The seal 4 passes through the gap 25 between 4 and the inner ring 13.
6 and the path shown by line Eb, that is, through the notches 50 and 51 and further through the seal 46, into the interior 26. The amount of inflow is determined by the gap G between surfaces 43 and 44 shown in FIG.

When vacuum pressure is applied to the hole 19, the rubber lining 28 is pulled into the inner ring 1 by the vacuum pressure as described above.
Press ball 3 downward and release ball 2 as shown in Figure 6.
9 and the ball raceway surfaces 47 of the inner ring 13 and outer ring 12,
The inner ring 13 is displaced downward due to the gap 48. Therefore, the amount of displacement F is managed in advance, and the seal gap G is determined by taking into consideration the increase in the amount of displacement F due to the runout of the inner ring lower surface 43 and the wear of the balls 29 and raceway surfaces 47 and 48. step H
It is sufficient to determine =F+G. Therefore, the only dimensions to be controlled are F and H, and the seal gap G can easily be 4 to 7 μm, and the effective diameter of the seal, that is, the J dimension in Fig. 2 in the conventional example. Since the dimensions can be made smaller, the cross-sectional area of the flow path, that is, (π×effective diameter Furthermore, since the effective diameter of the seal is small, the runout of the inner ring is not increased, so there is no need to increase the seal gap to avoid contact between the seals, which is also advantageous over the conventional method.

A further advantage is that if the flow path resistance R ₂ from the external space 52 to the seal 46 of the path Eb is made sufficiently smaller than the flow path resistance from the external space 52 to the seal 46 of the path Ea, almost no Air will stop flowing. Therefore, the path Eb has the meaning of a bypass with lower flow resistance than the path Ea, that is, setting R ₁ ≫ R ₂ is equivalent to opening the space 53 on the inflow side of the seal 46 to the external space 52. , spaces 53 and 52 have approximately the same pressure.
Furthermore, it is very easy to set R ₁ >>R ₂ . Therefore, the grease in the shield 24 of the bearing 11 does not flow out, and external dust does not enter between the inner ring 13, outer ring 12, and balls 29. Therefore, the life of the bearing is not shortened in any way. FIG. 7 shows the bearing 11, the seal member 42, and the holding member 55.
In this example, the holding member 55 has a notch 57 similar to the notch 50 shown in FIG. 4. In this way, the seal unit 56 can be used simply by press-fitting the outer circumferential surface 58 into the object, making it easy to handle. FIG. 8 shows an example in which a non-contact seal 60 is configured between the outer ring 12 and the seal member 59.
9 has a notch 61 similar to that shown in FIG. A holding member 62 press-fits and fixes the seal member 59 to the inner ring 13, and is press-fitted and fixed to the inner ring 13.
Reference numeral 63 is a hole provided in the holding member 62 that connects the notch 61 and the interior 26 to form an air circulation path, that is, a bypass Eb. Therefore, it is easy to make the flow resistance of path Eb smaller than that of path Ea, so almost no air flows through path Ea.
The same effect as in FIG. 6 can be achieved.

FIG. 9 shows an example in which two seal members 64 and 65 are provided to further reduce leakage. Seal member 6 in which notches 67 and 68 similar to those described above are formed
4 and 65 are the same cuts 69 and 70 as above, respectively.
The holding members 66 and 90 formed thereon are press-fixed to the inner ring 13 in the same manner as described above. Further, 71 is a sealing material made of resin, for example, for sealing the gap 72 between the holding members 66 and 67. Therefore, the bypass Eb includes notches 67, 69, 70, and 68.
It will be composed of: In this case, bearing 1
1 to the hub 7 without any trouble.
A bearing in which a collar 73 is formed on the bearing 2 may be used. In this example, since two non-contact seals are provided in series, it is possible to significantly reduce leakage. In addition, in FIGS. 7, 8, and 9, the sealing member and the holding member may be integrated as long as there is no problem in processing.

The basic configuration is the same as that for sealing vacuum pressure, but next we will discuss the configuration for sealing high pressure gas. Also, the same elements as in FIG. 9 will be explained using the same numbers.

FIG. 10 shows a modification of the configuration shown in FIG. 9 for use with high-pressure gas. Numeral 75 is a nut for pressing the collar 73 of the bearing 11 to fix the bearing 11 to the hub 7, and 76 is a wrench hole for screwing the nut 75 into the hub 7. A nut 77 is screwed into a holding member 78, and the sealing members 64, 65 are fixed to the inner ring 13 by pressure contact with the collar 79 of the holding member 78.
Similarly, 80 is a wrench hole.

Further, the holding member 78 is formed with a notch 81 constituting a bypass and a flat cut portion 83 for hooking a wrench into which a nipple 82 is screwed.

The only difference is that when high-pressure gas is supplied to the interior 83 through the nipple 82, the inner ring 13 is displaced upwards, contrary to the vacuum pressure case, and the other functions are the same.

If a strong bending moment acts on the nipple 82 in FIG. 10 and one bearing 11 is unstable, two bearings 11 may be used as shown in FIG. 11. In this case, a pipe-shaped member 84 into which the outer ring 12 is press-fitted is press-fitted into the hub 7 in order to support the two bearings 11 . The rest is the same as FIG. 10.

The configuration for sealing high-pressure gas has been described above using two seal members in series, but if some leakage is allowed, only one seal member may be used.

As described above, the present invention constitutes a non-contact seal by an annular member that is in close contact with the end face of the groove of at least one of the inner ring and the outer ring of a rolling bearing, and faces the end face of the other ring without contacting it. By providing an air passage, that is, a bypass, that connects the space between the inner ring and the outer ring on both end faces, the number of areas that require highly accurate dimensional control during seal processing is significantly reduced compared to conventional methods, and the seal is made smaller than before. A seal gap can be easily obtained. Therefore, leakage is reduced, the capacity of the source of high pressure gas or vacuum pressure can be lowered, and equipment costs and operating costs can also be reduced.

In addition, since the elements that make up the bearing, that is, the end face of the inner ring or outer ring, are used directly as the sealing surface, compared to conventional sealing surfaces that are located at a distance from the bearing, the sealing surface is less affected by the runout of the bearing. Since the runout is not enlarged, it is very advantageous for obtaining a minute seal gap, and
Since the effective diameter of the sealing surface is reduced and the cross-sectional area of the flow path can be reduced, this is also much more advantageous than the conventional method in terms of leakage.

Furthermore, by providing a bypass, it is possible to make the pressure at both ends of the bearing approximately the same, which prevents air from leaking between the inner and outer rings of the bearing. The bearing life can be maintained for a long time because the grease that has been applied to the bearing does not flow out and dust in the space does not enter during that time.

[Brief explanation of drawings]

FIG. 1 is a partial sectional view showing an example of a conventional non-contact seal, FIG. 2 is an enlarged view of the main part of FIG. 1, and FIG. 3 is a sectional view of the main part of an embodiment of the non-contact sealing device of the present invention. Figures 4 and 5 are perspective views of the same component alone, Figure 6 is an enlarged view of the main parts of Figure 3, and Figures 7 to 1.
FIG. 1 is a sectional view showing essential parts of other embodiments of the present invention. 1... Shaft, 2... Flange, 3... Vacuum chuck, 11... Radial ball bearing, 12... Outer ring, 1
3... Inner ring, 42, 59, 64, 65... Seal member, 51, 61, 67, 68... Notch, 5
0, 57, 69, 70, 81... cut portion.

Claims (1)

[Claims] 1. A rolling bearing capable of carrying radial and thrust loads, and an annular bearing having a sealing surface that closely contacts the end face of at least one of the inner ring and outer ring of the rolling bearing and faces the end face of the other ring without contacting it. a sealing member, a ring on the side that comes into close contact with the sealing member, and a holding means for integrally holding the sealing member, the space between the inner ring and the outer ring on one end face side of the bearing, and the space on the other side of the bearing. A non-contact sealing device, characterized in that a gas passage connecting a space between an inner ring and an outer ring on the end face side is configured to pass through the sealing member and the holding means, and the pressures in both spaces are made substantially the same.