JPH1014158A - Shaft seal device for dynamo-electric machine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To adjust the axial gap of a seal ring while maintaining surface roughness of the contact surface of a seal ring with a seal casing by dividing the seal casing in the axial direction, and fitting an adjusting means for adjusting the axial gap of the seal ring on its mating face. SOLUTION: Seal casings 15A, 15B which are divided in the axial direction are linked and fixed with a bolt 24 with an adjusting plate 23 inserted in its mating face. The thickness of the adjusting plate is in such a thickness as the surface roughness of the contact surface of the seal casings 15A, 15B with seal rings 16A, 16B is maintained in an optimum condition and the axial gap 18 of the seal rings 16A, 16B is an optimum value. Where the contact surface of the seal rings 16A, 16B with the seal casings 15A, 15B is machined, it is possible to keep the axial gap 18 of the seal rings 16A, 16B at the optimum value by reducing the thickness of the adjusting plate 23 by the cut-off length by means of machining.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a shaft sealing device for a rotating electric machine using hydrogen gas or the like as a cooling medium.

[0002]

2. Description of the Related Art For example, a hydrogen-cooled generator has a structure in which hydrogen is sealed in the machine and the rotor and the stator of the generator are cooled with hydrogen. The use of hydrogen as a cooling medium is
This is because the specific gravity is lower and the specific heat is higher than air. This hydrogen-cooled generator can perform high-efficiency operation by circulating and circulating hydrogen inside the device in a sealed and pressurized manner. Therefore, many large-capacity tarpin generators adopt this method.
In such a turbine generator, a shaft sealing device is provided at an end of the rotating electric machine so that hydrogen gas inside the machine does not leak out of the machine.

Hereinafter, a conventional shaft sealing device will be described with reference to the drawings. FIG. 5 is an end sectional view of a shaft sealing device for sealing the in-machine cooling hydrogen of the conventional hydrogen-cooled rotary electric machine. A seal casing 15 and a seal as a shaft sealing device so that the cooling hydrogen gas 13 surrounded by an end bracket 12 and the like supporting the stator frame end plate 11 does not leak from a gap between the rotating shaft 14 and the rotating electric machine. A ring 16 is provided and sealed here. FIG. 6 shows the seal casing 15 and the seal ring 1 as the shaft sealing device.
FIG. 6 is an enlarged cross-sectional view showing details of a sixth example.

The seal ring 16 is usually composed of a seal ring 16A and a seal ring 16B, and the inside diameter of each is slightly larger than the outside diameter of the shaft 14 of the rotating electric machine. The seal oil 17 is supplied from the seal casing 15 side at a pressure slightly higher than the cooling hydrogen gas pressure. The seal oil 17 is supplied to a minute gap 19 formed by the seal ring 16 and the shaft 14 through an axial gap 18 between the seal rings 16A and 16B. Thirteen external leaks are prevented. Here, the spring 20 presses the seal ring 16 and the shaft 14
This is for adjusting the minute gap 19 between the seal ring 16 and the seal ring 16.

FIG. 7 is a sectional view taken along the line AA of FIG.
As shown in the figure, the seal ring 16 is divided in the circumferential direction with respect to the shaft 14 which is the rotating shaft. The spring 20 is provided with a screw 2 provided on the seal casing 15.
It is fixed by 1. The spring 20 is annularly arranged along the seam between the seal ring 16A and the seal 16B, and the shaft 14 is optimally pressed.
, A minute gap 19 is formed. The adjustment of the minute gap 19 supplies the optimum oil amount.

[0006]

However, with the operation of the rotating electric machine, the seal oil 1 supplied to the minute gap 19 is changed.
7 may damage the outer peripheral surface of the shaft 14 or the inner peripheral surface of the seal ring 16.
In other words, the outer peripheral surface of the shaft 14 or the inner peripheral surface of the seal ring 16 is worn by the contaminant or the like, and the minute gap 19 becomes large. Therefore, the supply amount of the seal oil 17 to the minute gap 19 increases, and the hydrogen gas 13 dissolved in the seal oil 17 increases, which may lead to the leakage of the hydrogen gas 13.

If such a situation is a concern, the seal casing 16 is disassembled, and if the inner peripheral surface of the seal ring 16 is slightly damaged, the circumferential division surface of the seal ring 16 is sharpened. The inner diameter of the seal ring 16 is modified so as to form a predetermined minute gap 19. If the damage extends to the outer peripheral surface of the shaft 14, the outer diameter of the shaft 14 is shaved and modified, and the seal ring 16 is machined in the same manner as described above so as to conform to the outer diameter.

As described above, the seal ring 16 can be reused up to a predetermined size by correcting the inner diameter of the seal ring 16, but the spring 20 is
Due to the circumferential division surface and the inner diameter correction processing, there is a margin in the length, and the pressing force is weakened. As a result, the seal ring 1
A change occurs in the seating characteristic of No. 6, causing secondary problems such as an increase in the supply amount of the seal oil 17, a partial contact of the seal ring 16, and a loss of the seal function. For this reason, the spring 20 also needs to be remodeled when a change that exceeds a predetermined length is involved.

Further, in the shaft sealing device thus configured, the vibration of the shaft 14 is applied to the seal ring 16 while the seal ring 16 is strongly pressed against the contact surface with the seal casing 15 by the pressure of the seal oil 17. Since the transmission is performed, the sliding is repeated on the contact surface between the seal ring 16 and the seal casing 15, and the contact surface may be roughened.
Therefore, the slip resistance increases.

If this state continues for a long time, the seal ring 16
Is constrained from moving in the radial direction with respect to the rotating shaft, and cannot contact the vibration of the shaft 14 and strongly contacts the shaft. Therefore, the vibration of the rotating electric machine including the stator increases. In some cases, an emergency stop may occur to prevent damage.

Further, since a large-capacity generator with an increased hydrogen gas pressure in the machine is operated on a base load, a long-time continuous operation is required, and frequent stopping is difficult. So conventionally,
As means for maintaining the surface roughness of the contact surface between the seal casing 15 and the seal ring 16, a groove 22 is provided on the ring side of the contact surface, as shown in FIG. In some cases, the lubricating contact surface is formed by supplying the lubricating oil together with the lubricating oil No. 19 to reduce the friction coefficient. However, since the inner diameter of the seal ring 16 is damaged during operation, when the operation is stopped, if the circumferentially divided portion and the inner diameter of the seal ring 16 are trimmed in order to remove the groove, the groove 22 comes off from the seal casing 16. Therefore, continuous effects cannot be expected.

On the other hand, as another method for maintaining the contact surface roughness, there is known a method in which the respective contact surfaces of the seal ring 16 and the seal casing 15 are machined at a scheduled periodic inspection. Since the gap 18 in the axial direction is widened, the tightening force of the spring 20 is weakened, the minute gap 19 cannot be maintained at an appropriate value, the seal oil 17 for sealing the shaft increases, and the pressure decreases. That is, the increase in the flow rate of the seal oil 17 is caused by the internal cooling hydrogen gas 1
(3) An increase in the dissolved amount and a decrease in the pressure result in a hydrogen gas 13 leak. These are the essential functions of the shaft sealing device, and the seal ring 16 and the seal casing 15 must be periodically replaced to maintain the function.

Therefore, an object of the present invention is to maintain the surface roughness of the contact surface between the seal ring and the seal casing without periodically replacing all of the seal ring and the seal casing, and to increase the supply amount of the seal oil. It is an object of the present invention to obtain a shaft sealing device for a rotating electric machine that can eliminate leakage of cooling hydrogen gas and decrease in pressure due to cooling.

[0014]

According to a first aspect of the present invention, there is provided a rotary electric machine which is provided on an outer periphery of a shaft of a rotary electric machine for cooling by circulating a cooling medium sealed inside the rotary electric machine, and having a diameter larger than an outer diameter of the shaft. A shaft sealing device for a rotating electric machine including a seal ring having a large inner diameter, an axial gap formed by the seal ring for supplying seal oil to a shaft, and a seal casing for housing the seal ring,
The seal casing is divided in the axial direction, and an adjusting means for adjusting an axial gap in the seal ring is provided on a mating surface of the divided seal casing.

According to the first aspect of the invention, the adjusting means provided on the mating surface of the divided seal casing maintains the surface roughness of the contact surface between the seal ring and the seal casing while maintaining the axial direction of the seal ring. Adjust the gap.

According to a second aspect of the present invention, as the adjusting means in the first aspect of the present invention, an adjusting plate provided between the mating surfaces of the divided seal casings is used.

According to the second aspect of the invention, in addition to the operation of the first aspect, the axial gap of the seal ring is adjusted by the thickness of the adjustment plate.

According to a third aspect of the present invention, as the adjusting plate of the second aspect of the invention, a plurality of thin plates are used.

According to the third aspect of the invention, in addition to the operation of the second aspect of the invention, the thickness of the adjusting plate is selected to be a predetermined thickness according to the number of laminated thin plates.

According to a fourth aspect of the present invention, as the adjusting means in the first aspect of the present invention, a jack screw for adjusting a distance between mating surfaces of the divided seal casings is used.

According to a fourth aspect of the present invention, in addition to the operation of the first aspect, the axial gap in the seal ring is adjusted by the screwing amount of the jack screw.

[0022]

Embodiments of the present invention will be described below. FIG. 1 is a sectional view of a shaft sealing device according to a first embodiment of the present invention. In the first embodiment, the seal casing 15 is divided in the axial direction, and an adjusting plate 23 is provided on the mating surface of the divided seal casings 15A and 15B. That is, the adjusting plate 23 functions as adjusting means for adjusting the axial gap 18 in the seal ring 16, and the axial gap 18 in the seal ring 16 is adjusted by the thickness of the adjusting plate 23. Further, the divided seal casing 15A,
15B is connected and fixed by bolts 22. Other configurations are the same as those of the conventional example shown in FIG. 6, and therefore, the same portions are denoted by the same reference characters and description thereof will be omitted.

In FIG. 1, the seal casing 16 is
The casing is divided into a seal casing 16A and a seal casing 16B, and an adjusting plate 23 is inserted between the mating surfaces. The thickness of the adjusting plate 23 is such that the surface roughness of the contact surface between the seal casing 15 and the seal ring is appropriately maintained, and the length of the axial gap 18 of the seal ring 16 is an appropriate length. Is selected. That is, the adjustment plate 2
3, the axial gap 18 of the seal ring 16
Adjust the length of. And the seal casing 15A,
15B is connected and fixed by bolts 22 with the adjustment plate 23 interposed therebetween.

Thus, when the contact surface between the seal ring 16 and the seal casing 15 is machined, the thickness of the adjusting plate 23 is reduced by the amount cut by the machining, so that the axial gap of the seal ring 16 is reduced. 18 can be kept at an appropriate value. Therefore, it is possible to provide an inexpensive and highly reliable shaft sealing device for a rotating electric machine without a time loss of remanufacturing the seal ring 16 and the spring 20.

Here, the adjusting plate 23 may be formed by stacking a plurality of thin plates. By doing so, the gap between the mating surfaces of the seal casing 15 can be adjusted by increasing or decreasing the number of thin plates, and the length of the axial gap 18 in the seal ring 16 can be maintained at an appropriate value.

In the first embodiment, the seal casing 15 is divided in the axial direction, and an adjusting plate whose thickness can be adjusted is provided on the mating surface of the divided portions. It is possible to maintain the axial gap of the seal ring at an appropriate value while appropriately maintaining the surface roughness of the contact surface. Therefore, even if the contact surface between the seal ring 16 and the seal casing 15 is machined, the axial gap 18 of the seal ring can be maintained at an appropriate value by adjusting the thickness of the adjustment plate 23. In addition, it is not necessary to change the spring 20.

Next, a second embodiment of the present invention will be described with reference to FIGS. In this second embodiment,
As an adjusting means for adjusting the axial gap 18 in the seal ring 16, a divided seal casing 15 is used.
Jack screw 2 for adjusting the distance between the mating surfaces of A and 15B
5 is used.

FIG. 2 is a vertical sectional view in the axial direction of a shaft sealing device according to a second embodiment of the present invention. The sealing casing 15A and the sealing casing 15B divided in the axial direction are fixed by tightening their mating surfaces with bolts 24. That is, the seal casing 15A and the seal casing 15B are formed in a cylindrical shape on the outer periphery of the shaft 14, and are configured to house the seal ring 16. The divided casing 15A
A jack screw 25 is arranged in the middle of a mounting position of a bolt 24 for connecting the bolt and the seal casing 15B, and the bolt 24 and the jack screw 25 are alternately arranged. This jack screw 25 is used for the seal casing 1.
This is a screw for adjusting and holding the gap between the mating surfaces of 5A and the seal casing 15B.

FIG. 3 is a sectional view taken along line BB of FIG. 2, and FIG. 4 is a sectional view taken along line CC of FIG. As can be seen from FIG. 3, the seal casing 15A and the seal casing 15B divided in the axial direction are fixed by tightening their mating surfaces with bolts 24. Also,
As can be seen from FIG. 4, the jack screw 25 pushes the mating surface of the seal casing 15A, and by turning the jack screw 25, the seal casing 15A
The gap between the mating surfaces of the seal casing and the seal casing 15B is adjusted and held.

That is, the interval between the mating surfaces of the seal casing 15A and the seal casing 15B is adjusted by the jack 25.
, And then the seal casing 15 with bolts 24
A mating surface between A and the seal casing 15B is connected and fixed. As described above, the gap between the mating surfaces of the seal casing 15A and the seal casing 15B can be adjusted by the jack screw 25, so that the axial gap 18 of the seal ring 16 can be finely adjusted.

In the second embodiment, the distance between the mating surfaces of the divided portions in the axial direction of the seal casing 16 can be adjusted by the jackscrew 25.
6 can be maintained at an appropriate value.
Therefore, the seal ring 16 and the seal casing 15
By adjusting the thickness of the adjustment plate 23, the axial gap 18 of the seal ring can be maintained at an appropriate value even if the contact surface with the contact hole is machined, so that the seal ring 16 and the spring 20 need not be reworked.

[0032]

As described above, according to the shaft sealing device for a rotary electric machine of the present invention, even if the contact surface between the seal ring and the seal casing is machined, the optimum spring tightening force can be set. It is possible to provide an inexpensive and highly reliable shaft sealing device for a rotating electric machine without a loss of time for re-manufacturing a seal ring or a spring.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view of a shaft sealing device according to a first embodiment of the present invention.

FIG. 2 is an axial vertical sectional view of a shaft sealing device according to a second embodiment of the present invention.

FIG. 3 is a sectional view taken along line BB in FIG. 2;

FIG. 4 is a sectional view taken along line CC in FIG. 3;

FIG. 5 is an end sectional view of a shaft sealing device for sealing the in-machine cooling hydrogen of the conventional hydrogen-cooled rotary electric machine.

FIG. 6 is an enlarged sectional view showing details of a seal casing and a seal ring which are conventional shaft sealing devices.

FIG. 7 is a sectional view taken along line AA of FIG. 6;

FIG. 8 is an explanatory view in the case of maintaining the surface roughness of the contact surface between the casing and the seal ring in the conventional example.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 11 Stator frame end plate 12 End bracket 13 Hydrogen gas 14 Shaft 15 Seal casing 16 Seal ring 17 Seal oil 18 Axial gap 19 Micro gap 20 Spring 21 Screw 22 Bolt 23 Adjusting plate 24 Bolt 25 Jack screw

Claims (4)

[Claims] A sealing ring provided on an outer periphery of a shaft of the rotating electric machine for cooling by circulating a cooling medium sealed in the rotating electric machine, the inner ring having an inner diameter larger than an outer diameter of the shaft; An axial gap formed by a seal ring for supplying seal oil to the shaft, and a shaft sealing device for a rotating electrical machine including a seal casing for housing the seal ring, wherein the seal casing is divided in the axial direction, A shaft sealing device for a rotating electric machine, wherein an adjusting means for adjusting the axial gap in the seal ring is provided on the mating surface of the divided seal casing. 2. The shaft sealing device for a rotating electric machine according to claim 1, wherein the adjusting means is an adjusting plate provided between the mating surfaces of the divided seal casings. 3. The shaft sealing device for a rotating electric machine according to claim 2, wherein the adjusting plate is configured by stacking a plurality of thin plates. 4. The shaft sealing device for a rotating electric machine according to claim 1, wherein the adjusting means is a jack screw for adjusting a gap between mating surfaces of the divided seal casings.