JPH0615176Y2 - Gas seal device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial field of application) The present invention is mainly used in the field of sealing technology of bearings, and particularly relates to a device for sealing by using gas.

(Prior art and problems) In the case of a rotating body supported by a non-rotating body via a rolling bearing, the annular space formed between the rotating body and the non-rotating body is covered with dust or cutting chips. In order to prevent foreign matter from entering the inside, it is necessary to seal the outside space. In particular, in a precise and high-speed rotating body, a contact type seal cannot be used between the rotating body and the non-rotating body, and the labyrinth seal and the annular space between the rotating body and the non-rotating body must be narrowed. It took a form in which a gas such as air was blown toward the outside from a plurality of places in the periphery.

However, the former, that is, the labyrinth seal, has a complicated shape and is troublesome to process, and it is not so effective.In the latter, that is, when air is blown out from a plurality of locations, uniform conditions are not obtained over the entire surrounding range. As a result, good results cannot be obtained, and in order to make the results uniform, it is necessary to provide outlets at a large number of places, which causes problems in processing. Further, in the latter case, it is effective to make the annular space as narrow as possible, but it cannot be so narrow due to the problem of mounting accuracy.

(Means and Actions for Solving Problems) An object of the present invention is to solve the above-mentioned conventional problems and to provide a gas sealing device having a simple structure and capable of uniformly sealing the entire circumference. There is.

In order to achieve the above-mentioned object, the present invention seals an annular space between a non-rotating body and a rotating body supported by the non-rotating body via a rolling bearing from an external space. An annular member having a gas receiving port for receiving the sealing gas and an annular chamber communicating with the gas receiving port and opening inward in the radial direction is provided on the non-rotating body side. A porous ring which is set smaller than the inner diameter of the member and forms an extremely narrow narrow gap with the opposing outer peripheral surface of the rotating body over the entire circumference, closes the opening of the annular chamber of the annular member and forms the narrow gap. It is configured to be supported by the annular member so as to be movable in the radial direction by receiving the gas pressure inside.

According to the present invention having such a configuration, a gas such as air flowing out from a gas receiving port provided at one or a plurality of positions in the circumferential direction is in the annular chamber and spreads around the entire circumference due to the resistance of the porous ring. When reaching the narrow gap through the small holes of the porous ring, a uniform pressure distribution is obtained in the circumferential direction. Therefore, the sealing gas blown out from the narrow gap is in a completely uniform state in the circumferential direction, and a perfect seal is achieved. At this time, even if the annular member is attached to the non-rotating body with an error in the radial direction, the porous ring is movably supported by the annular member in the radial direction. The radial position is automatically adjusted so that the distribution in the circumferential direction is uniform, that is, the gap with the rotating body is uniform in the circumferential direction, and the radial position is automatically adjusted. Therefore, the inner diameter of the porous ring can be processed so that the narrow gap is extremely narrowed regardless of the mounting accuracy.

The gas blown out from the narrow gap can not only be blown toward the external space, but a part of the gas can be directed toward the bearing inside the axial direction to prevent the lubricant from flowing out.

(Embodiment) An embodiment of the present invention will be described below with reference to the accompanying drawings.

FIG. 1 is a vertical cross-sectional view showing a first embodiment of the present invention. In FIG. 1, reference numeral 1 denotes a housing which is a non-rotating body, and inside the housing 1, a rolling body is provided via a rolling bearing 2, for example, in the case of the drawing. The high speed spindle 3 of the machine tool is supported.

The bearing 2 has its position in the axially preloaded state by the spacer 4 on the outer ring side and the attachment member 5 attached to the housing 1, and on the inner ring side by the spacer 6 and the step portion 3A of the main shaft. Has been defined.

An annular member 9 is attached to the attachment member 5.

The annular member 9 is provided with one or a plurality of gas receiving ports 10 penetrating to an inner diameter surface of the annular member 9 at an appropriate position on the outer periphery.
Can be connected to A. Bellows 15 extend radially inward from both edges of the inner diameter surface of the annular member 9, and a porous ring 12 is attached to the inner peripheral edge thereof. Thus, the annular member 9, the bellows 15 and the porous ring 12 form an annular chamber 11 communicating with the gas receiving port 10. Also, the porous ring
The inner diameter surface of 12 is finished so as to form a very narrow gap 8 with the outer peripheral surface of the main shaft 3 facing the outer surface.

Next, the operation of the apparatus of this embodiment as described above will be described. When the apparatus is operated, that is, when the main shaft 3 is rotated, a sealing gas, for example, air is fed into the gas inlet 10.
At this time, the gas may be at room temperature, but it is preferably at room temperature or lower if a cooling effect is also expected.

When the gas enters the annular chamber 11, it receives the resistance of the porous ring 12 and spreads in the circumferential direction in the annular chamber 11, and then reaches the narrow gap 8 through the small holes of the porous ring 12. that time,
The gas that has passed through the porous ring 12 is completely in a uniform pressure state at any position in the circumferential direction, and is uniformly blown out in the circumferential direction from the narrow space 8 toward both the external space and the bearing. Thus, it is possible to obtain a uniform sealing effect in the circumferential direction, completely prevent foreign matter such as dust from entering the inside, and, for example, the lubrication system flows out to the outside of so-called air oil, oil mist, oil jet, etc. Even if it is easy, it is possible to prevent these lubricants from flowing out.

In the present embodiment, the object of the present invention cannot be sufficiently achieved unless the narrow gap 8 is uniform in the circumferential direction. However, in this embodiment, the porous ring 12 and the annular member 9 are bellows 15.
Since the porous ring 12 is movable in the radial direction, the pressure distribution in the narrow gap 8 in the circumferential direction is even if the narrow gap 8 is eccentric due to some reason. The porous ring 12 moves to a uniform balance position and is automatically aligned in the radial direction so that the narrow gap 8 is uniform, resulting in a perfectly uniform seal in the circumferential direction. An example of the cause of the eccentricity is an error in mounting the annular member 9. In other words, it means that the narrow gap 8 is made uniform in the circumferential direction regardless of this mounting error.

Next, a second embodiment of the present invention will be described with reference to FIG. In this embodiment, the annular member 9 and the bellows 15 are the same as in the previous embodiment, but the porous ring 28 forms a narrow gap with the main shaft 3 at two positions separated in the axial direction. Is characterized by. In this case, the length (width) of the porous ring 28 in the axial direction is set to be larger than that of the previous embodiment, an annular groove 28A is formed in the middle, and the inner surface of the porous ring 28 is a paint for blunting the surface of the porous ring. 29 etc. are applied. As a result, the gas pressure acts effectively in the narrow gap between the above two positions,
The tendency of the porous ring to collapse in the axial direction is eliminated. This tendency to collapse is seen when using the narrow annular ring in the previous example.

Next, a third embodiment of the present invention will be described with reference to FIG. In this embodiment, the annular chamber 31 is formed inside the annular member 39, and two O-rings 35 are provided on the inner side wall of the annular chamber 31 so as to surround the main shaft, where the porous ring 32 is provided. Are guided to be movable in the radial direction while sealing the annular chamber 31. At that time, the inner diameter of the porous ring 32 is
Of course, it is smaller than the inner diameter of the annular member 39. According to the present embodiment, compared with the mounting of the bellows in the above-mentioned two embodiments, the troublesome work of mounting on the bellows is not required and the turning process is simplified due to the simple sectional shape. For that reason, it has the advantage of being extremely simple to manufacture. Further, in this embodiment, it is possible to form a narrow gap at two positions as in the second embodiment.

(Effects of the Invention) The present invention provides a porous ring on the non-rotating body side so that gas is blown out through the porous ring into a narrow gap formed between the porous ring and the rotating body, and Since the porous ring is movable in the radial direction, in addition to the effect that a uniform and complete seal can be performed over the entire circumference, even if the annular member that temporarily supports the porous ring is attached due to radial error, etc. Even if there is a factor of eccentricity, the porous ring is self-aligned to maintain a uniform narrow gap in the circumferential direction,
As described above, the complete sealing can be performed, and the structure thereof can be simplified, and it is not necessary to give special consideration to the mounting accuracy. Moreover, the present invention has an extremely simple structure, can be manufactured at low cost, and can be easily added to the existing device without any special work.

[Brief description of drawings]

FIG. 1 is a longitudinal sectional view showing a first embodiment device of the present invention, and FIG.
FIG. 3 is a vertical sectional view showing a second embodiment device of the present invention, and FIG. 3 is a vertical sectional view showing a third embodiment device of the present invention. 1 ...... Non-rotating body (housing) 2 ...... Rolling bearing 3 ...... Rotating body (spindle) 8 ...... Narrow gap 9; 39 ...... Annular member 10 ...... Gas inlet 11; 31 ...... Annular chamber 12 ...... Porous ring 15 …… Bellows 35 …… O-ring

Claims (4)

[Scope of utility model registration request] 1. A gas receiver for receiving a sealing gas from the outside, wherein an annular space between a non-rotating body and a rotating body supported by the non-rotating body via a rolling bearing is sealed to an external space. An annular member is provided on the non-rotating body side in which an annular chamber is formed which communicates with the inlet and opens inward in the radial direction. The annular member has an inner diameter smaller than the inner diameter of the annular member. A porous ring that forms an extremely narrow narrow gap with the opposing outer peripheral surface of the rotating body over the entire circumference closes the opening of the annular chamber of the annular member and receives gas pressure in the narrow gap. A gas sealing device, which is movably supported in the radial direction by the annular member. 2. The gas sealing device according to claim (1), wherein the porous ring is attached to the annular member by a member having elasticity in the radial direction such as a bellows. 3. The utility model registration claim (2), wherein the porous ring forms a narrow gap with the rotating body at at least two positions separated from each other in the axial direction. Gas seal device. 4. The gas according to claim 1 wherein the porous ring is guided movably in the radial direction by an O-ring provided on the inner wall of the annular chamber. Sealing device.