JP2757936B2 - Sealing oil supply device for rotating electric machines - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a sealing oil supply device for supplying sealing oil to a shaft sealing portion of a rotating electric machine filled with hydrogen gas.

[0002]

2. Description of the Related Art FIG. 6 is a system diagram showing a conventional sealing oil supply device for a rotary electric machine disclosed in Japanese Patent Application Laid-Open No. 4-344147. In the figure, reference numeral 1 denotes a rotating electric machine filled with hydrogen gas, 2 denotes a rotating shaft of the rotating electric machine 1, 3 denotes a sealer, and 4 denotes a hydrogen side for supplying sealing oil to the hydrogen side (inside the machine) of the sealer 3. A sealing oil supply pipe 5, an air-side sealing oil supply pipe 5 for supplying sealing oil to the air side (outside of the machine) of the sealing device 3, and a sealing oil 6 discharged from the sealing device 3 to the hydrogen side temporarily stay and seal. A bubble collecting box installed for removing bubbles in oil, 7 is a hydrogen-side sealing oil drain pipe, 8 is a bearing oil drain pipe that integrally discharges the air side and bearing oil (not shown), and 9 is air The loop seal tank 10 for temporarily stagnating the side sealing oil drainage and the bearing drainage and discharging the hydrogen gas and the air, and the reference numeral 10 denotes the hydrogen gas and the air separated in the loop seal tank 9 for safe outside, for example, outdoors. A discharge pipe 11 for guiding the pressure of the upper space in the loop seal tank 9 The vapor extractor is installed so as to be lower than the pressure of the section and to extract hydrogen gas and air in the loop seal tank 9 and forcibly discharge it outside, 12 is an air-side sealed oil return pipe, and 13 is the rotary electric machine 1 A hydrogen gas shut-off tank for shutting off the flow of hydrogen gas inside to the outside, 14 is a float valve for keeping the oil level in the hydrogen gas shut-off tank 13 constant, and 15 is an oil amount of the hydrogen side sealing oil circuit. A sealing oil supply pipe 16 for replenishing from the air side sealing oil circuit when the supply oil runs short, supplies the sealing oil in the hydrogen gas blocking tank 13 to the hydrogen side of the sealing device 3, and supplies the hydrogen side sealing oil from the sealing device 3. A hydrogen-side sealed oil pump provided in a hydrogen-side sealed oil circuit configured to return the drained oil to the hydrogen gas shut-off tank 13;
Reference numerals 7 and 18 denote the sealing oil in the loop seal tank 9 and the sealing device 3.
A common air-side sealing oil pump (AC) provided in an air-side sealing oil circuit configured to supply the air-side sealing oil drainage from the sealer 3 to the loop seal tank 9 together with the bearing oil drainage. Powered by power supply) and emergency air-side sealed oil pump (driven by DC power supply), 19 is a check valve, 20 is a pump inlet valve, 21 is a safety valve, and 22 is a sealer 3 that seals the air side from hydrogen gas pressure inside the machine. In order to adjust the supply amount from the service air side sealing oil pump 17 or the emergency air side sealing oil pump 18 so that the oil pressure becomes higher by a certain value, it was installed on a bypass circuit connecting the discharge side and the suction side of the pump. Differential pressure regulating valve, 2
3 is an air-side sealing oil cooler, 24 is an air-side sealing oil filter, 25 is a hydrogen-side sealing oil for setting the amount of oil supplied from the hydrogen-side sealing oil pump 16 to the amount of oil required for the hydrogen-side sealing oil circuit. A manual bypass valve installed for the purpose of returning the flow rate of the pump other than that supplied to the inner sealer 3 to the suction side of the hydrogen-side sealing oil pump 16, 26 is a safety valve, 27 is a hydrogen-side sealing oil cooler, 28 is Hydrogen side sealed oil filter, 29 is sealer 3
A pressure equalizing valve 30 installed on the hydrogen-side sealing oil circuit for the purpose of adjusting the hydrogen-side sealing oil pressure so that the air-side sealing oil pressure and the hydrogen-side sealing oil pressure are equal pressures. Vacuum degassing tank 31 is a float valve provided to automatically maintain the oil level of vacuum degassing tank 30 constant, and 32 is an oil level alarm that detects an abnormal oil level in vacuum degassing tank 30. Bowl, 3
Numeral 3 promotes deaeration by spraying an air-side sealer other than the supply amount of the service air-side seal oil pump 17 or the emergency air-side seal oil pump 18 to the inner sealer 3 in the vacuum deaeration tank. A spray nozzle tube for causing the air-sealing oil returned from the loop seal tank 9 to the deaeration plate 34 for degassing effect; Dish introduction pipe for raising
Is a vacuum gauge, 37 is an oil level gauge, 38 is a vacuum deaeration tank inlet valve, 3
9 is a vacuum pump unit, and 40 is an air side sealing oil deaerator.

Next, the operation of the above conventional device will be described. The hydrogen gas in the rotating electric machine 1 is sealed by a sealing oil circulating in both the hydrogen-side sealing oil circuit and the air-side sealing oil circuit. In the air-side sealing oil circuit, during normal operation, the sealing oil is pushed out by the service air-side sealing oil pump 17, maintained at a pressure higher than the hydrogen gas pressure in the machine by a constant value by the differential pressure regulating valve 22, and supplied to the sealer 3. Is done. Then, the sealing oil is pushed out to the air side along the rotating shaft 2, and together with the bearing oil (not shown), passes through the loop seal tank 9 and exchanges with the sealing device 3 to reduce or increase the sealing oil. It is sent to the vacuum degassing tank 30 to make up for excess or deficiency. The sealing oil sent into the vacuum degassing tank 30 is degassed by the degassing dish 34 and becomes an upper oil reservoir in the vacuum degassing tank 30. In the vacuum degassing tank 30, the degassed sealing oil is sent out from a lower oil reservoir to a regular sealing oil pump 17. The common air side sealed oil pump 17
When the emergency stops, the emergency air side sealing oil pump 18 driven by the DC power supply starts, and the service air side sealing oil pump 17
Performs the same function as. In the hydrogen-side sealing oil circuit, the sealing oil is pushed out by the hydrogen-side sealing oil pump 16, and the hydrogen-side and air-side sealing are performed by the equalizing valve 29 so that the total amount of the sealing oil in the hydrogen-side sealing oil circuit does not become excessive or insufficient. The hydraulic pressure is supplied to the sealing device 3 as much as possible. Then, the sealing oil is pushed out to the hydrogen side along the rotating shaft 2, enters the bubble collecting box 6, overflows and enters the hydrogen gas blocking tank 13. Here, the hydrogen gas contained as bubbles in the sealing oil is removed, and the sealing oil drawn out from the bottom of the hydrogen gas shut-off tank 13 is sent to the hydrogen-side sealing oil pump 16. In this way, the air-side sealing oil circuit and the hydrogen-side sealing oil circuit are completed and the same circulation is repeated.

[0004] The conventional sealing oil supply device is configured such that the sealing oil on the air side and the sealing oil on the hydrogen side are divided into separate circuits as described above, and the pressures of both are equalized. Thus, for example, the sealing oil containing the hydrogen gas inside the device in the sealing device 3 flows into the air side, and the consumption of the hydrogen gas inside the device due to the degassing process in the vacuum degassing tank 30 can be suppressed.
Also, an air-side sealing oil deaerator 40 for degassing the air-side sealing oil.
, A small pressure difference that cannot be completely adjusted by the pressure equalizing valve 29 is generated, and the exchange of the sealing oil between the air side and the hydrogen side in the sealer 3 causes the air contained in the air-side sealing oil to rotate. It is possible to prevent the windage loss in the rotating electric machine 1 caused by the intrusion into the rotating electric machine 1 and the decrease in the purity of hydrogen gas in the rotating electric machine 1 from increasing. With these two systems, it is possible to configure a sealing oil supply device for a rotating electric machine that consumes a small amount of hydrogen and does not reduce hydrogen gas purity.

[0005]

Since the conventional sealing oil supply device is constructed as described above, the air-side sealing oil deaerator 40 is provided with the total amount of sealing oil required for the air side of the sealer 3 (10%).
(0 to 150 liters / minute), the vacuum deaeration tank 30 is particularly large, and the air-side sealed oil deaerator 40 is large and heavy. For this reason, there is a drawback that the installation place is also limited, and how to reduce the size and weight becomes an important issue.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-described problems, and is intended to reduce the size and weight of a conventional sealing oil supply device having a large and heavy air-side sealing oil deaeration device. It is an object of the present invention to obtain a sealed oil supply device which does not hinder the installation place, etc., while retaining the function as before by replacing the device.

[0007]

According to a first aspect of the present invention, there is provided a sealing oil supply device for a rotary electric machine, wherein a sealing oil supply pipe for supplying sealing oil from an air sealing oil circuit to a hydrogen sealing oil circuit is provided in the middle of an air sealing oil supply pipe. And a pressure of the sealing oil in the hydrogen-side sealing oil supply circuit was set higher than that of the air-side sealing oil.

According to a second aspect of the present invention, there is provided a rotary oil supply device for a rotary electric machine, which includes a spray nozzle tube and a deaeration dish as a sealing oil deaeration device, and a vacuum deaeration tank for deaeration of air from the air side sealing oil. A float valve for automatically maintaining a constant oil level in the vacuum deaeration tank, an oil level alarm disposed in the vacuum deaeration tank, and maintaining a constant high vacuum in the vacuum deaeration tank. A vacuum degassing device comprising a vacuum pump unit for sucking air degassed from the air side sealing oil to the outside of the vacuum degassing tank was used.

According to a third aspect of the present invention, there is provided a sealing oil supply device for a rotating electric machine, wherein two float valves for automatically maintaining a constant oil level in a vacuum degassing tank are provided in parallel, and each float valve is degassed. This is the one that succeeded the dish introduction tube.

According to a fourth aspect of the present invention, there is provided a sealing oil supply device for a rotary electric machine, wherein a replenishing oil pump is provided between an air side sealing oil deaerator and a hydrogen side sealing oil circuit.

According to a fifth aspect of the present invention, there is provided a sealing oil supply device for a rotary electric machine, wherein a bypass pipe is provided in parallel with a sealing oil supply pipe and a check valve is provided.

According to a sixth aspect of the present invention, there is provided a sealing oil supply device for a rotary electric machine, wherein a bypass pipe is provided in parallel with a sealing oil supply pipe and an electromagnetic valve is provided.

According to a seventh aspect of the present invention, an air-side sealing oil deaerator and a hydrogen-side sealing oil circuit are connected by two parallel sealing oil supply pipes, one of which is sealed. The oil supply pipe is provided with a supply oil pump driven by an AC power supply, and the other sealed oil supply pipe is provided with a supply oil pump driven by a DC power supply.

[0014]

According to a first aspect of the present invention, there is provided a sealing oil supply device for a rotary electric machine in which the pressure of the hydrogen-side sealing oil is slightly higher than the pressure of the air-side sealing oil so that the hydrogen-side sealing oil is supplied to the air side. In addition to flowing into the sealing oil circuit, only the sealing oil flowing into the air side is supplied from the air-side sealing oil circuit to the hydrogen-side sealing oil circuit, and the replenishing sealing oil is degassed by a vacuum deaerator. That is, it is sufficient to degas only the sealing oil to be replenished to the hydrogen side, and the amount of sealing oil to be replenished in this way can be extremely small, about 1/20 to 1/30 of the conventional air-side sealing oil. In addition, the amount of sealing oil to be degassed can be reduced, and the vacuum degassing tank and the like constituting the air-side sealing oil deaerator can be reduced in size and weight.

According to the third aspect of the present invention, in the sealing oil supply device for a rotating electric machine, two float valves are provided in parallel, so that even if one of the float valves fails, the function does not stop and the air side is provided. It is possible to improve the reliability of oil inflow and outflow as the whole sealing oil deaerator.

According to the fifth aspect of the present invention, the supply reliability of the supply oil from the air side circuit to the hydrogen side circuit is improved by providing the bypass pipe and the check valve. Things.

In the sealing oil supply device for a rotating electric machine according to claim 6 of the present invention, by providing a solenoid valve instead of a check valve, the supply reliability of supply oil from the air side circuit to the hydrogen side circuit is improved. At the same time, the size of the replenishing oil pump and the drive motor can be reduced.

In the sealing oil supply device for a rotary electric machine according to claim 7 of the present invention, by providing two supply oil pumps in parallel, the supply reliability of supply oil from the air side circuit to the hydrogen side circuit is improved. At the same time, the purity of the hydrogen gas in the rotating electric machine can be reliably maintained at a high level.

[0019]

【Example】

Embodiment 1 FIG. FIG. 1 is a system diagram showing a sealing oil supply device for a rotating electric machine according to a first embodiment of the present invention. In the drawing, the same parts as those in the prior art are denoted by the same reference numerals. 41 is a hydrogen gas shut-off tank 1 which draws sealing oil from the vacuum deaeration tank 30
3 and a replenishing oil pump to be sent to the spray nozzle pipe 33;
Reference numeral 42 denotes a supply oil pump inlet valve, and reference numeral 43 denotes a sealed oil supply pipe.

Next, the operation will be described. If the pressure in the sealer 3 is forcibly increased on the hydrogen side by the equalizing valve 29, a small amount of the sealing oil on the hydrogen side flows into the air side. As a result, the oil level in the hydrogen gas shut-off tank 13 decreases, so that the float valve 14 is opened, and the vacuum deaeration tank 3 is opened.
The air-side sealing oil degassed in 0 is pushed out by the oil supply pump 41, enters the hydrogen gas shut-off tank 13, and keeps the oil level at a constant value. When the sealing oil is supplied to the hydrogen gas shut-off tank 13, the oil level of the vacuum deaeration tank 30 is lowered, so that the float valve 31 is opened, and the sealing oil is supplied to the deaeration tray 34 from the air-side sealing oil circuit. Then, the oil level in the vacuum degassing tank 30 is maintained at a constant value, and at the same time, air is degassed from the air side sealing oil. In addition, a small amount is supplied to the hydrogen side circuit from the vacuum degassing tank 30 by the replenishing oil pump 41, and most of the rest is returned to the vacuum degassing tank 30 through the spray nozzle 34, so that the degassing effect is enhanced.

As described above, according to this embodiment, the air-side sealing oil deaerator 40 provided with the supply oil pump 41 is provided in the middle of the sealing oil supply pipe 43 to the hydrogen gas shut-off tank 13. The pressure of the sealing oil on the hydrogen side can always be higher than the pressure of the sealing oil on the air side, so that the sealing oil on the air side does not flow into the sealing oil on the hydrogen side in the sealer 3.
And it is only necessary to degas the air-side sealing oil to replenish it to the hydrogen-side sealing oil, so the amount of deaeration of the sealing oil required to reduce the amount of air entering the rotating electrical machine is greatly reduced. As a result, the size and weight of the air-side sealing oil deaerator 40 can be reduced, and the device can be manufactured at low cost.

Embodiment 2 FIG. Next, a second embodiment of the present invention will be described with reference to FIG. In the first embodiment, the replenishing oil pump 41 is operated from the vacuum deaeration tank 30 to supply the sealing oil of the air side circuit to the hydrogen side circuit.
If 1 stops, this sealing oil supply will stop. Therefore, as shown in FIG. 2, the bypass pipe 44 and the check valves 45, 4
6 are provided. During normal operation, the replenishing oil pump 4
(1) The outlet pressure of the vacuum deaeration tank is increased by increasing the outlet pressure
Is closed, and when the replenishing oil pump 41 is stopped, the pump outlet pressure decreases. Conversely, the replenishing oil pump outlet check valve 45 is closed, and the vacuum deaeration tank bypass check valve 46 is opened. Refill automatically. By providing the above circuit, the supply reliability of the supply oil from the air side circuit to the hydrogen side circuit can be improved.

Embodiment 3 FIG. Next, a third embodiment of the present invention will be described with reference to FIG. In the second embodiment, the bypass pipe 44 and the check valves 45 and 46 are provided in consideration of the case where the replenishing oil pump 41 is stopped. However, as shown in FIG. Use a solenoid valve 47 instead of
Automatic replenishment can be performed by opening the solenoid valve 47 when the replenishing oil pump stops or when the oil level in the vacuum deaeration tank 30 decreases. By providing the above circuit, the supply reliability of supply oil from the air side circuit to the hydrogen side circuit is improved, and
In the case of the second embodiment, since the check valve 46 is provided, the discharge pressure of the replenishing oil pump 41 must always be higher than the sealing oil pressure supplied from the air-side sealing oil circuit. Had to be increased,
If the solenoid valve 47 is used, it cannot be opened / closed in a pressure balance, so that the discharge pressure of the replenishing oil pump 41 does not depend on the sealing oil pressure supplied from the air-side sealing circuit. The size of the motor can be reduced.

Embodiment 4 FIG. Next, a fourth embodiment of the present invention will be described with reference to FIG. In the third embodiment, in consideration of the case where the replenishing oil pump 41 stops, the solenoid valve 4
7 to supply the replenishing oil from the air side circuit to the hydrogen side circuit so that the replenishing oil pump is stopped or the solenoid valve 47 is opened when the oil level in the vacuum deaeration tank 30 is lowered so that the replenishing oil is automatically supplied. Although the reliability is improved, the sealing oil that has not been degassed as it is is supplied to the hydrogen side, and air may enter the sealing oil on the hydrogen side. Therefore, as shown in FIG. 4, in parallel with the replenishing oil pump 41 driven by the AC power source, the replenishing oil pump 48 driven by the DC power source and the pump inlet valve 4
9 is provided so that the deaerated supply oil can always be supplied. As a result, the supply reliability of the replenishment oil from the air side circuit to the hydrogen side circuit can be improved, and the purity of the hydrogen gas in the rotary electric machine 1 can be reliably maintained at a high level.

Embodiment 5 FIG. Next, a fifth embodiment of the present invention will be described with reference to FIG. In the first to fourth embodiments, the supply of the sealing oil to the vacuum deaeration tank 30 is performed only from the float valve 31, and if the float valve 31 fails, the function stops. Therefore, in the fifth embodiment, an emergency float valve 50 and a deaeration dish introduction pipe 51 are provided in parallel with the float valve 31 in order to improve the supply reliability of this portion, and the oil in the air-side sealing oil deaerator as a whole is provided. Has improved the reliability of entering and exiting. Although FIG. 5 shows a case where the float valves are provided in parallel in the structure of the fourth embodiment, the present invention can be similarly applied to the structures of the first to third embodiments.

[0026]

According to the first, second and fourth aspects of the present invention, an air-side sealing oil deaerator is provided in the middle of a sealing oil supply pipe for supplying sealing oil from the air-side sealing oil circuit to the hydrogen-side sealing oil circuit. As a result, the amount of sealing oil degassing required to reduce the amount of air entering the rotating electric machine can be significantly reduced, and the size and weight of the air-side sealing oil degassing device can be reduced. In addition, the apparatus can be manufactured at low cost.

In the third aspect, two float valves of the vacuum deaerator are provided in parallel, so that even if one of the float valves fails, the function does not stop, and the entire air-side sealed oil deaerator is provided. As a result, the reliability of oil inflow and outflow can be improved.

According to the fifth aspect of the invention, by providing the bypass pipe and the check valve, the supply reliability of the replenishing oil from the air side circuit to the hydrogen side circuit can be improved.

According to the sixth aspect of the invention, by providing an electromagnetic valve instead of the check valve, the supply reliability of the supply oil from the air side circuit to the hydrogen side circuit is improved, and the supply oil pump and the drive motor are provided. Can be reduced in size.

In the invention of claim 7, by providing two replenishing oil pumps in parallel, the supply reliability of the replenishing oil from the air side circuit to the hydrogen side circuit is improved, and the hydrogen gas purity in the rotating electric machine is improved. Can be reliably maintained at a high purity.

[Brief description of the drawings]

FIG. 1 is a system diagram showing a sealing oil supply device for a rotary electric machine according to Embodiment 1 of the present invention.

FIG. 2 is a system diagram showing a sealing oil supply device for a rotary electric machine according to Embodiment 2 of the present invention.

FIG. 3 is a system diagram showing a sealing oil supply device for a rotary electric machine according to Embodiment 3 of the present invention.

FIG. 4 is a system diagram showing a sealing oil supply device for a rotary electric machine according to Embodiment 4 of the present invention.

FIG. 5 is a system diagram showing a sealing oil supply device for a rotary electric machine according to Embodiment 5 of the present invention.

FIG. 6 is a system diagram showing a conventional sealing oil supply device for a rotating electric machine.

[Explanation of symbols]

1 rotating electric machine, 2 rotating shaft, 3 sealer, 4 hydrogen-side sealing oil supply pipe, 5 air-side sealing oil supply pipe, 6 foam box, 7
Hydrogen side seal oil drain pipe, 8 bearing oil drain pipe, 9 loop seal tank, 10 discharge pipe, 11 vapor extractor, 12 air side seal oil return pipe, 13 hydrogen gas shutoff tank, 14 float valve, 15 seal oil supply pipe , 16 Hydrogen-side sealed oil pump, 17 Regular air-side sealed oil pump, 1
8 Emergency air side sealing oil pump, 19 Check valve, 20
Pump inlet valve, 21 Safety valve, 22 Differential pressure regulating valve, 23
Air side sealed oil cooler, 24 air side sealed oil filter,
25 Manual bypass valve, 26 Safety valve, 27 Hydrogen side sealed oil cooler, 28 Hydrogen side sealed oil filter, 29 Equalization valve, 30 Vacuum deaeration tank, 31 Float valve, 32 Oil level alarm, 33 Spray nozzle tube, 34 Desorption Dish, 35
Deaeration dish introduction pipe, 36 vacuum gauge, 37 oil level gauge, 38 vacuum deaeration tank inlet valve, 39 vacuum pump unit, 40 air side sealing oil deaerator, 41 refill oil pump (ACP),
42 supply oil pump inlet valve, 43 supply oil pump outlet check valve, 44 vacuum deaeration tank bypass check valve, 45 vacuum deaeration tank bypass solenoid valve, 46 supply oil pump (DCP),
47 refueling oil pump inlet valve, 48 emergency float valve.

Claims (7)

(57) [Claims] 1. A hydrogen-side sealing oil supply circuit and an air-side sealing oil supply circuit for separately supplying sealing oil to a hydrogen side and an air side of a sealer of a shaft seal portion of a rotary electric machine sealed with hydrogen gas. In a sealing oil supply device for a rotating electric machine, a sealing oil deaerator for vacuum degassing the air side sealing oil in the middle of a sealing oil supply pipe for supplying sealing oil from the air side sealing oil circuit to the hydrogen side sealing oil circuit is provided. A sealing oil supply device for a rotating electric machine, wherein the sealing oil supply device is installed and the pressure of the sealing oil in the hydrogen-side sealing oil supply circuit is set higher than the sealing oil on the air side. 2. The sealed oil degassing device has a built-in spray nozzle tube and a degassing dish, and has a vacuum degassing tank for degassing air from the air side sealing oil, and an oil level of the vacuum degassing tank. A float valve for maintaining the pressure constant constant, an oil level alarm disposed in the vacuum degassing tank, and air degassed from the air side sealing oil while maintaining a constant high vacuum in the vacuum degassing tank. And a vacuum pump unit for sucking the oil out of the vacuum degassing tank. 3. Two float valves for automatically maintaining a constant oil level in the vacuum deaeration tank are provided in parallel,
3. The sealing oil supply device for a rotary electric machine according to claim 2, wherein a deaeration dish introduction pipe is connected to each float valve. 4. The rotary electric machine according to claim 1, wherein a replenishing oil pump is provided between the sealing oil deaerator and the hydrogen-side sealing oil circuit. Sealing oil supply device. 5. A bypass pipe provided with a check valve is provided in parallel with the sealing oil supply pipe, and when supply from the sealing oil supply pipe is stopped, hydrogen is supplied from the air-side sealing oil circuit through the bypass pipe. The sealing oil supply device for a rotary electric machine according to any one of claims 1 to 4, wherein sealing oil is supplied to the side sealing oil circuit. 6. A bypass pipe provided with an electromagnetic valve is provided in parallel with the sealing oil supply pipe, and when replenishment from the sealing oil supply pipe is stopped, the air-side sealing oil circuit passes through the bypass pipe to the hydrogen side. The sealing oil supply device for a rotary electric machine according to any one of claims 1 to 4, wherein sealing oil is supplied to the sealing oil circuit. 7. The sealing oil deaerator and the hydrogen-side sealing oil circuit are connected by two sealing oil supply pipes arranged in parallel, and the one sealing oil supply pipe is connected to a supply oil pump driven by an AC power supply. The sealing oil supply device for a rotary electric machine according to any one of claims 1 to 3, wherein a DC oil supply-driven oil supply pump is provided in the other sealing oil supply pipe.