JPS6027261Y2 - Sealing device - Google Patents

Description

[Detailed Description of the Invention] [Field of Application of the Invention] The present invention relates to a sealing device used in a rotating machine.

[Background of the idea]

A typical example of a conventional sealing device of this type will be described with reference to FIGS. 1 and 2. 1 is a casing, 2 is a rotating shaft passing through the casing 1, 3 is a sleeve shrink-fitted to the rotating shaft 2, and 4 , 5 is a seal ring holder attached to the casing 1, and 6 is a seal ring holder attached to the rotary shaft 2 by the seal ring holders 4 and 5.
Seal ring 7 is supported concentrically with seal ring 6.
8 is a Babbitt coupled to the inner peripheral surface 6a of the seal ring 6, and 9 is an annular gap formed between the Babbitt 8 and the sleeve 3 through which seal oil flows. .

Reference numeral 10 indicates an oil cutting plate attached to the end surface of the seal ring holder 4 on the atmosphere side, and reference numeral 11 indicates an oil cutting plate attached to the casing 1 so as to face the rotating shaft 2.
End bushing 12 installed in the casing 1
13 is a seal oil passage provided in the passage 7,
This is a seal oil passage provided in the seal ring holder 5 so as to communicate with the seal ring holder 12.

In the seal device having the above structure, the seal oil flows through the passage 12,
13.7, it flows through the gap 9 between the Babbitt 8 coupled to the seal ring 6 and the sleeve 3 shrink-fitted to the rotary shaft 2 to perform a sealing action.

In this case, the seal oil flowing through the gap is
The rotation causes the Babbitt 8 to swing around in the circumferential direction,
Oil whirl and oil whip may occur, causing vibration.

[Purpose of invention]

This invention was developed to address the above issues, and prevents the oil between the rotating shaft and the seal ring from swinging around in the circumferential direction.
It is an object of the present invention to provide a sealing device that prevents the occurrence of oil whirl and oil whip and performs a complete sealing action.

[Summary of the idea]

The present invention provides a sealing device in which seal oil is supplied to an annular gap formed between a rotating shaft and a seal ring, in which a plurality of closing grooves are formed on the inner circumferential surface of the seal ring in the axial direction from both sides to the middle. In addition, the closing grooves are arranged in a staggered manner in the circumferential direction.

[Example of idea]

An embodiment of the present invention will be described below with reference to the drawings.

In Figures 3 to 5, 2 is the rotating shaft, and 15 is the rotating shaft 2.
16 is a passage for seal oil 5 provided in the radial direction of the seal ring 11.5, and 17a and 17b are axially supported on the inner circumferential surface 15a of the seal ring 15, from both sides to the middle. The closing grooves are provided up to the inner circumferential surface 15a in a staggered manner in the circumferential direction of the inner circumferential surface 15a.

18 is a gap formed between the inner circumferential surface 15a of the seal ring and the rotating shaft 2.

Since the present embodiment is configured as described above, the seal oil that has flowed into the gap 18 through the passage 16 tends to whirl around in the circumferential direction of the inner peripheral surface 15a of the seal ring due to the rotation of the rotating shaft 2. Closing grooves 17 are provided in the inner peripheral surface 15a in the axial direction and arranged in a staggered manner in the circumferential direction.
a and 17b can prevent the oil from swirling around and prevent oil whirl and oil whip from occurring.

That is, the seal oil that has flowed into the inner surface 15a of the seal ring 15 from the high pressure side flows into the blockage R17a that extends to approximately the center of the seal ring 15, and when it reaches the center of this groove 17a, it flows out in the circumferential direction, and the low pressure It flows into the blocking groove 17b extending from the side toward the center and flows out to the low pressure side.

Seal oil flows through blockages 117a and 17 arranged in a staggered manner.
By sequentially flowing the oil, the flow that attempts to circulate continuously along the surface of the rotating shaft 2 is cut off at multiple points in the circumferential direction by the blockages 117a and 17b, thereby preventing the oil from swirling around.

By preventing this oil from swirling around, it is possible to prevent oil whirl and oil whip from occurring.

In order to generate oil whirl and oil whip, oil exists between the rotating shaft 2 and the seal ring 15, and as the rotating shaft 2 rotates, oil with an average speed of about 172 of the shaft surface circumferential speed rotates. It is generated by traveling around the area.

By cutting off the flow of oil that attempts to circulate continuously around the rotating shaft with the above-described structure, it is possible to prevent the oil from swirling around and to prevent the occurrence of oil whirl and oil whip.

Next, the necessity of arranging the closing grooves 17a, 17b in a staggered manner in the circumferential direction will be explained.

Providing a groove on the inner surface of the seal ring 15 means that the gap between the rotating shaft 2 and the inner surface of the seal ring 15 is different between the grooved part and the non-grooved part, and naturally the gap in the part corresponding to the groove is different. It becomes much larger in comparison.

Therefore, if the groove is a groove that simply communicates from the high pressure side to the low pressure side of the seal ring, a very large amount of oil would be required to satisfy the sealing function in this state.

In addition, the flow of oil tends to be uneven, causing local backflow, and there is a risk that gas may leak out.

This problem can be solved by arranging the closing grooves in a staggered manner in the circumferential direction of the seal ring.

In other words, it is capable of achieving a complete sealing function.

[Effect of idea]

As explained above, according to the present invention, it is possible to prevent the oil from swirling around in the circumferential direction, prevent the occurrence of oil whirl and oil whip, and achieve complete sealing.

[Brief explanation of the drawing]

Fig. 1 is a sectional view of a conventional sealing device, Fig. 2 is a sectional view of the same main part, Fig. 3 is a sectional view of a main part of the sealing device of the present invention, and Fig. 4 is a sectional view of the main part of the sealing device of the present invention.
The figure is a sectional view taken along the line IV--IV in FIG. 3, and FIG. 5 is a developed view of the inner circumferential surface of the seal ring used in the present invention. 2...Rotating shaft, 15...Seal ring, 15a...Seal ring inner peripheral surface, 17a, 1
7b...Closing groove, 18...Annular gap.

Claims (1)

[Scope of utility model registration request] In a sealing device in which seal oil is supplied to an annular gap formed between a rotating shaft and a seal ring, a plurality of closing grooves are formed on the inner circumferential surface of the seal ring from both sides in the axial direction to an intermediate portion thereof. A sealing device characterized in that the closing grooves are provided in a staggered manner in the circumferential direction.