JPS599788B2 - Shaft sealing device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a shaft sealing device for a rotating shaft in a rotating machine such as a liquid-cooled generator that cools a rotor coil by introducing a cooling liquid into the rotor.

Fig. 1 shows a conventional shaft sealing device of this kind, in which 1 is a rotating shaft, 2 is a sealing thread groove formed on the outer periphery of the rotating shaft 1, and 3 is a predetermined gap between the outer periphery of the thread groove 2 and 5 is an annular pressure chamber formed to surround the outer periphery of the rotating shaft 1 at a position adjacent to the screw holder 2, and 4 is an inner periphery of the pressure chamber 5. 6 is a compressor, I is a rotational speed detector of a rotating shaft, and 8 is inserted in the middle of a pipe connecting the compressor 6 and the pressure chamber 5; The control valve 8 is a compressed air control valve whose opening degree is controlled by the rotational speed detector 7 mentioned above.

Since the conventional shaft sealing device for a rotating shaft is configured as described above, when the rotating shaft 1 rotates at high speed, the liquid that is about to leak is pushed back to the high pressure side 10 by the pumping action of the thread groove 2, and the rotating shaft is stopped. When the pump action by the thread groove 2 stops or decreases during low-speed rotation, the rotational speed detector 7 detects the rotational speed of the rotating shaft, and the control valve 8 is opened and the pumping action is stopped or reduced. When compressed air No. 6 is introduced into the pressure chamber 5, the flexible membrane 4 deforms as shown by the broken line in FIG. It is something.

However, if the flexible membrane 4 is pressed against the outer circumferential surface of the rotating shaft 1 for a long time when the rotating shaft 1 rotates at a low speed, the wear will be extremely severe due to friction, etc., and it will be difficult to maintain the performance of the shaft sealing device for a long period of time. Not only is it not possible;
Complete? 6, a control valve 8, a rotational speed detector 7, etc. are required, which has the disadvantage of being extremely expensive.

This invention was made with attention to this point, and when the rotating shaft is stopped without using an expensive compressor, control valve, and rotational speed detector like the conventional ones mentioned above,
Another object of the present invention is to provide a shaft sealing device that can perform sealing inexpensively and reliably during low-speed rotation.

That is, FIGS. 2 to 6 all show one embodiment of this invention, and the overall configuration shown in FIG. 2 will be explained first.

In FIG. 2, reference numeral 1 indicates a rotary shaft having a threaded groove 2 for a seal formed thereon at a predetermined position on the outer circumference of the housing 3 through a predetermined gap, and 11 is fixed to one side of the housing 3 on the outer circumference. A support ring having a U-shaped cross section with an annular groove 12 formed in a part thereof, and an inner seal ring 15 having a rubber ring 13 inside and a friction ring 14 made of carbon or the like formed on the outer periphery is fitted into the annular groove 12. ing.

Reference numeral 16 denotes an outer seal having an L-shaped cross section and made of an elastic material, which is fixed at a predetermined position of the rotating shaft 10 and has a friction ring 17 fixed to the inner circumferential surface of the free end, which corresponds to the friction ring 14 of the inner seal ring 15 so as to be able to move toward and away from it. ring, the above friction ring 1
7 is in contact with the friction ring 14 of the inner seal ring 15 as shown by the broken line when the rotating shaft 1 is stopped or rotating at low speed to seal the inside and outside, and when the rotating shaft 1 is rotating at a predetermined high speed,
It is configured to separate from the friction ring 14 due to the centrifugal force.

3 shows only the support ring 11, and the front view and sectional view of FIG. 4 show only the outer seal ring 16.

Next, details of the inner seal ring 15 will be explained.

This inner seal ring 15 is divided into a plurality of parts 15a to 15f in the circumferential direction as shown in FIG. 5, and the connecting portions thereof are constructed as shown in FIG.

That is, one seal ring 15a and the other adjacent seal ring 15b are formed with a concave portion 18 and a convex portion 19 that are slidably fitted into each other, and the connecting bolts 20 protruding from the four portions 18 are connected to the convex portion 19. After passing through the inside, they are connected to each other by a nut 22 via a compression spring 21.

Therefore, when the nut 22 is tightened to compress the compression spring 21, the force that tries to draw both the seal rings 15a and 15b toward each other becomes stronger, overcoming the elastic force of the rubber ring 13 fitted inside the annular groove 12. As a result, both seal rings 15a and 15b come close to each other, and as a result, the diameter of inner seal ring 15 becomes smaller.

Furthermore, when the nut 22 is loosened to reduce the compression force of the compression spring 21, the elastic force of the rubber ring 13 pushes the seal rings 15a, 15b apart from each other, and it goes without saying that the diameter of the inner seal ring 15 increases. do not have.

As described above, the reason why the diameter of the inner seal ring 15 is made variable is to adjust the timing of contact and separation between the friction ring 14 of the inner seal ring 15 and the friction ring 17 of the outer seal ring 16 that slides thereon. This is to adjust the timing deviation caused by wear of the friction rings 14 and 17.

The rubber ring 13 fitted inside the inner seal ring 15 in the annular groove 12 acts elastically to adjust the diameter of the inner seal ring 15, and also serves as an inner and outer seal in the annular groove 12. Of course, there are also.

According to this invention, as described above, the inner seal ring 15 is attached to the support ring 11 fixed to the fixed housing 3, and the inner seal ring 15 is attached to the rotary shaft 1 when it rotates at low speed. The outer seal ring 16 made of an elastic material is fixed, and when the rotary shaft 1 rotates at high speed, the centrifugal force causes the outer seal ring 16 to separate from the inner seal ring 15. It does not require expensive compressors, control valves, rotation speed detectors, etc., and has excellent young fruits that can be inexpensively and reliably sealed when the rotating shaft is stopped or rotated at low speed. .

Furthermore, if the inner seal ring 15 is divided into a plurality of parts in the circumferential direction and each part is adjustable and connected by a compression spring and a connecting bolt, the diameter of the inner seal ring 15 can be adjusted.

[Brief explanation of the drawing]

FIG. 1 is a sectional view showing a conventional shaft sealing device, FIG. 2 is a sectional view showing an embodiment of the present invention, FIG. 3A is a sectional view of a support ring, FIG. 3B is a front view thereof, and FIG. 4A is a front view of the outer seal ring, FIG. 4B is a sectional view thereof, FIG. 5 is a front view of the inner seal ring, FIG. 6A is an enlarged sectional view taken along line VI-VI in FIG. Figure 6B is its front view. In the drawings, 1 is a rotating shaft, 2 is a sealing thread groove, 3 is a housing, 14 and 17 are friction rings, 15 is an inner seal ring, and 16 is an outer seal ring. Note that the same reference numerals in the figures indicate the same or corresponding parts.

Claims (1)

[Scope of Claims] 1. An inner seal ring that is concentrically attached to a housing with a rubber ring inside that corresponds to a high-speed seal thread groove formed on the outer peripheral surface of the rotating shaft with a predetermined gap therebetween, and the above-mentioned rotating shaft. and an outer seal ring made of an elastic material that contacts the inner seal ring attached to the inner seal ring to seal the inside and the outside, and the inner seal ring is formed by adjustablely connecting a plurality of seal rings divided in the circumferential direction. A shaft sealing device, characterized in that when the rotating shaft rotates at high speed, the outer seal ring is automatically separated from the inner seal ring by the centrifugal force. 2. The shaft sealing device according to claim 1, wherein the outer seal ring and the inner seal ring have friction rings that contact each other.