JPH053821Y2 - - Google Patents

Description

[Detailed description of the invention] (Industrial application field) The present invention is used in the technical field of rotating body air seals, and is particularly applied to bearings that support rotating bodies, and is formed between the housing side and the rotating body. The present invention relates to a rotating body air seal device that prevents dust and the like from entering through a labyrinth seal groove.

(Prior art and problems) As this type of device, for example,
As shown in the figure, a rotating body 3 such as a spindle is supported in a housing 1 via a bearing 2, and a labyrinth seal groove 4 is formed between the housing side and the rotating body at a portion axially outward from the bearing 2. However, an air seal device is known in which blow-off openings 6 for blowing out air from an air reservoir on the housing side are provided near the open air side opening of the labyrinth seal groove 4 and are uniformly distributed in the circumferential direction.

In the above device, compressed air is guided to an annular air reservoir chamber 11 through a guide hole 10.
Air is blown out from the blow-off opening 6 that communicates with the bearing 2, and dust from the outside passes through the labyrinth seal groove 4 into the bearing 2.
This prevents them from entering inside. however,
The guide hole 10 communicates with the annular air reservoir chamber 11 at one or several locations in the circumferential direction, and the pressure within the air reservoir chamber 11 tends to be high in the communicating portion of the guide hole 10 and low elsewhere. There is a blowout opening 6 above.
This tendency also appears in the amount of air blown out from the seal, creating a problem in that the sealing properties are not uniform in the circumferential direction.

As a solution to this problem, it may be possible to provide the guide holes 10 as shown in the figure at many locations in the circumferential direction, but such a guide hole requires a large number of man-hours to process and is not a good idea. I can't say that.

Means and operation for solving the problem) The present invention solves the problems of the conventional device described above, and blows air completely uniformly in the circumferential direction near the open air side opening of the labyrinth seal groove. The purpose is to provide a rotary body air sealing device for air sealing.

In order to achieve the above object, the present invention supports a rotating body within a housing via a bearing, forms a labyrinth seal groove between the housing side and the rotating body at a portion axially outward from the bearing, In an air seal device in which blow-off openings for blowing out air from an air reservoir on the housing side are provided near the outside air side opening of the labyrinth seal groove, and are uniformly distributed in the circumferential direction, the air reservoir is located on the axis of the rotating body. The annular space is formed within the housing as a concentric annular space, and is divided into a plurality of concentric annular chambers by an annular wall extending in the axial direction from the housing side. The radially outer annular chamber is connected to the compressed air supply source, and the radially innermost annular chamber is connected to the outlet opening. and the outlet opening is oriented outward in the axial direction.

According to the present invention, the compressed air supplied from the compressed air supply source is made uniform in the circumferential direction by sequentially passing through the plurality of environmental chambers from one end side to the other end side, and reaches the blowout opening. Sometimes it is completely uniform. Thus, the rotary air seal device of the invention is equally sealed in the circumferential direction.

(Embodiment) An embodiment of the present invention will be described below based on FIG. 1 of the accompanying drawings.

In the figure, 20 is a housing, and inside its cylindrical hole,
A spindle 23 as a rotating body is supported via bearings 21 and 22. The spindle 23 has a tapered hole 24 at one end and is structured to hold a tool holder (not shown).

A ring body 25, 2 is provided at the left end of the housing 20.
6 is fixed and forms a part of the housing side, and forms a labyrinth seal groove 27 of a known shape between it and the spindle 23. Further, one ring body 26 also positions the outer ring of the bearing 21 at an inwardly extending flange portion 26A.

An L-shaped through hole 28 is provided in the ring body 25, and an axially extending portion of the through hole 28 connects with an axial hole 29 of the housing to form a guide hole 30. The guide hole 30 is connected to a compressed air supply device (not shown) via piping on the right side.

The ring body 25 has an annular recess formed in its inner diameter portion, into which the radially extending portion of the through hole 28 opens. The recess has a shape that opens in the axial direction, and a lid 35 having an annular wall 34 extending axially inward is fitted into the opening. In the fitted state, the lid 35 substantially closes the recess while maintaining a uniform distance in the circumferential direction between the lid 35 and the radially innermost wall 25A of the recess, forming an annular air reservoir chamber 31; A blowout opening 36 is formed in the space between the two ends of the labyrinth seal groove 27, and the blowout opening 36 is oriented toward the outside air side opening of the labyrinth seal groove 27. Further, the lid body 35 divides the air reservoir chamber 31 into two annular spaces 3 in the radial direction by the annular wall 34 while leaving a gap at the tip of the annular wall 34.
2,32 are formed.

According to the device of this embodiment as described above, the compressed air supplied through the guide hole 30 enters the annular chamber 32 outside the air reservoir chamber 31, diffuses in the circumferential direction within the annular chamber 32, and then closes the lid. The inner annular chamber 33 is reached through the gap at the tip of the annular wall 34 of the body 35 . Therefore, when the compressed air enters the inner annular chamber 33, it has a completely uniform pressure distribution in the circumferential direction. In this way, the compressed air is blown out from the blow-off opening 25A uniformly in the circumferential direction near the open air side opening of the labyrinth seal groove 27, and the labyrinth seal groove 27 is sealed from the outside air in this area.

The present invention is not limited to the above embodiments, and may be modified. For example, the air reservoir can be three or more annular chambers, and the annular chambers can be arranged one after the other in the axial direction. However, as a means for making each annular chamber communicate with each other, instead of making each annular chamber communicate between the two, holes provided in the partition wall of each annular space may be used. In that case, it is preferable to provide the hole or gap at a position that does not coincide with the direction of the guide hole for introducing compressed air into the annular chamber.

(Effects of the invention) As described above, the present invention is applicable to a device in which the air for air sealing is blown into the open air side opening portion of the labyrinth seal groove after passing through the air reservoir inside the housing side. , the air reservoir chamber is made of a plurality of annular chambers communicating through holes or holes, and the pressure of the air is made uniform in the circumferential direction by passing through the annular chambers in sequence, so that the amount of air blown out as an air seal is reduced.・The speed, etc. becomes completely equal in the circumferential direction, increasing the sealing effect. Furthermore, in order to obtain such an effect, there is no need for the complicated process of providing a plurality of guide holes in the circumferential direction for feeding compressed air into the air reservoir chamber.

[Brief explanation of the drawing]

Fig. 1 is a sectional view showing one embodiment of the present invention;
The figure is a sectional view showing a conventional device. 20... Housing, 21, 22... Bearing, 2
3... Labyrinth seal groove, 30... Guide hole, 31
...Air reservoir chamber, 32, 33...Annular chamber, 36...
Air outlet.

Claims (1)

[Claim for Utility Model Registration] A rotating body is supported in the housing via a bearing, and a labyrinth seal groove is formed between the housing side and the rotating body at a portion axially outward from the bearing. In an air seal device, in which blow-off openings for blowing out air from the air reservoir on the housing side are provided near the outside air side opening of the housing and are evenly distributed in the circumferential direction, the air reservoir is concentric with the axis of the rotating body. An annular space is formed within the housing and is divided into a plurality of concentric annular chambers by an annular wall extending in the axial direction from the housing side, and the plurality of annular chambers are connected to the tip of the annular wall and an air reservoir. The radially outer annular chamber is connected to the compressed air supply source, and the radially innermost annular chamber communicates with the blow-off opening. A rotary air seal device characterized in that the opening is oriented outward in the axial direction.