JPH0223911Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention is designed to prevent fluid from leaking from the gap between the housing and the shaft, especially in emergencies such as damage to the shaft sealing device, or when inspecting the inside of the equipment. This invention relates to a sealing device that blocks leakage.

[Conventional technology and its problems]

Conventionally, an inflatable seal is known as an example of a sealing device used for emergency purposes. As shown in FIG. 3, this inflatable seal is installed in an annular groove 6 formed in the circumferential direction on the inner periphery of the shaft hole 5 of the device housing 4, and is made of an annular rubber-like elastic material having a hollow portion 2. A pressure introduction pipe 7 is provided in a housing 4 and has an inner end connected to an opening 3 of the main body hollow part 2 and an outer end connected to an external pressure source (not shown). Since the main body 1 is in a contracted state with no pressure introduced into its hollow portion 2, the inner circumferential surface 1' of the main body 1 is the outer circumferential surface of the shaft 8 loosely inserted into the shaft hole 5. Although it is separated from the hollow part 8', in an emergency such as when a shaft sealing device (not shown) is damaged, inspected, or replaced, the external pressure source is connected to the hollow part 2 through the pressure introduction pipe 7.
By pressurizing the inside and expanding the main body 1, the inner circumferential surface 1' of the main body 1 comes into close contact with the outer circumferential surface 8' of the shaft 8, thereby preventing leakage of the fluid sealed inside the device.

However, this type of conventional sealing device has a complicated structure and is expensive. Therefore, the present invention utilizes the widely used O-ring to provide a simple and inexpensive sealing device. It is.

[Means for solving problems]

For this purpose, the sealing device of the present invention is provided in an annular groove formed on the inner circumferential surface of the shaft hole of the equipment housing. An O-ring made of a rubber-like elastic material whose diameter can be freely expanded and contracted is installed, and a space surrounded by the O-ring and the bottom of the annular groove is formed from the entire circumference toward the inside of the housing. It has a structure in which it communicates with pressure introduction means that generates negative pressure and positive pressure through an annular gap.

[Effect]

In the above configuration, the O-ring installed in the annular groove on the inner periphery of the housing can freely expand or contract in diameter by varying the pressure in the space in the annular groove by the pressure introducing means through the annular gap. be able to. More specifically, the diameter of the O-ring is expanded by evacuating the space, and the O-ring is separated from the shaft. The O-ring is always in close contact with both radial surfaces of the annular groove, and the gap connected to the pressure introducing means is formed around the entire circumference of the annular groove, so that the O-ring cannot be expanded by vacuuming. The diameter is ensured. Furthermore, in an emergency, by pressurizing the space, the diameter of the O-ring is reduced to bring it into close contact with the shaft, thereby preventing leakage of internal fluid.

〔Example〕

Next, an embodiment of the present invention is shown in FIGS. 1 and 2.
This will be explained based on the diagram.

In the figure, a reference numeral 11 is installed in an annular groove 14 that extends in the circumferential direction at a predetermined portion of the inner periphery of the shaft hole 13 of the housing 12, and is attached to both radial surfaces 14a and 14b of the annular groove 14. A rubber-like elastic material that is always in close contact with each other, and whose diameter can be freely expanded and contracted, and which makes contact with and separates from the bottom surface 14c of the outer diameter portion of the annular groove 14 and the outer circumferential surface 15' of the shaft 15 loosely inserted into the shaft hole 13. An annular gap 16 is formed from one corner of the bottom of the annular groove 14 in the outer radial direction over the entire circumference, and the gap 16 is connected to a pressure introduction path 17. It communicates with an external pressure source (not shown). Note that the void 16 is
The width W
is extremely narrow, about 0.5mm.

In a normal case, the sealing device having the above-mentioned structure has both radial surfaces 14a and 1 of the annular groove 14, as shown in FIG.
4b, the bottom surface 14c, and the O-ring 11, the space 18 is evacuated by the external pressure source via the gap 16 and the pressure introduction path 17. The O-ring 11 has both radial surfaces 1
4a, 14b to isolate the space 18 from the inner diameter side space 19 of the annular groove 14, the outer circumferential surface 1 of the shaft 15 due to the differential pressure between the spaces 19, 18.
5' and expands in diameter toward the outer diameter side so as to come into close contact with the bottom surface 14c of the annular groove 14, and therefore does not perform a sealing function between the housing 12 and the shaft 15. In this case, since the gap 16 is narrow, there is no possibility that a part of the O-ring 11 will be drawn into the gap 16 and damaged due to vacuuming, and the gap 16 is formed in the annular groove 14.
Since it extends over the entire circumference of the space 18, even if a part of the space 18 becomes clogged due to close contact with the O-ring 11, the evacuation of the space 18 will not be hindered.

In addition, in the event of an emergency such as damage to the shaft sealing device (not shown),
During inspection and replacement work, if it is necessary to prevent the fluid sealed inside the device from leaking from between the housing 12 and the shaft 15, as shown in FIG.
8 is pressurized via the cavity 16 and the pressure introduction path 17 by the external pressure source. As described above, the O-ring 11 has both radial surfaces 14a of the annular groove 14,
14b, the pressure causes the annular groove 14 to move radially inward and come into pressure contact with the outer circumferential surface 15' of the shaft 15, thereby blocking leakage of the fluid sealed inside the machine.

[Effect of idea]

As is clear from the above explanation, the present invention does not use a conventional inflatable seal as a sealing device for use in emergencies, but instead uses a versatile O-ring, which is attached to the bottom of the annular groove in which the O-ring is installed. By applying negative pressure or positive pressure from a gap provided around the entire corner, the O-ring can be reliably expanded or contracted even though it does not have a thin shape that easily flexibly deforms. , it is possible to make them move toward and away from the periphery of the shaft, and the structure is simple and the cost can be reduced.

[Brief explanation of the drawing]

1 and 2 are half-cut sectional views showing the operating state of a sealing device according to an embodiment of the present invention, and FIG. 3 is a half-cut sectional view showing an example of a conventional sealing device. 11...O-ring, 12...housing, 13
...Shaft hole, 14...Annular groove, 14a, 14b...
Radial surface, 15... shaft, 16... void, 17...
Pressure introduction path, 18...space.

Claims (1)

[Scope of utility model registration request] In a sealing device that blocks and seals a gap between an inner circumferential surface of a shaft hole of a device housing and an outer circumferential surface of a shaft loosely inserted into the shaft hole, the sealing device is configured such that the sealing device is configured to seal a gap between the inner circumferential surface of a shaft hole of an equipment housing and the outer circumferential surface of a shaft loosely inserted into the shaft hole. An O-ring made of a rubber-like elastic material is installed in the annular groove extending into the annular groove, which constantly seals against both radial surfaces of the annular groove, and whose diameter can be freely expanded and contracted within the annular groove. A space surrounded by the ring and the bottom of the annular groove is a pressure introducing means for generating negative pressure and positive pressure through an annular gap formed from the entire circumference toward the inside of the housing. A sealing device characterized by being connected.