JP2022098908A - Bearing structure for water turbine power generator - Google Patents

Abstract

To provide a bearing structure that restrains an increase in an installation area and does not cause a decrease in power generation efficiency even if the speed and size of a water turbine power generator are increased.SOLUTION: The bearing structure for a water turbine power generator according to an embodiment comprises: a first bearing and a second bearing supporting a rotating shaft of the water turbine power generator; a transfer part provided in the first bearing for transferring a cooling material supplied in order to cool the first bearing, from the inside of the first bearing to the outside; and a cooling part for cooling the cooling material transferred by the transfer part. The cooling material cooled by the cooling part is supplied to both the first bearing and the second bearing in order to cool the first bearing and the second bearing. The cooling material supplied in order to cool the second bearing is transferred to the first bearing, and merged with the cooling material supplied in order to cool the first bearing.SELECTED DRAWING: Figure 1

Description

An embodiment of the present invention relates to a bearing structure of a water turbine generator, and more particularly to a bearing structure of a water turbine generator which has been increased in size and speed.

In recent years, in power supply, from the viewpoint of preventing global warming, renewable energy such as natural energy power generation such as solar power, wind power, and hydropower and renewable energy such as biomass power generation have been attracting attention and their introduction has been promoted. The installation of hydroelectric power plants, which is one of them, is becoming more active than before.

In hydroelectric power generation, a water turbine is rotated by the flow of water, and the power is used to rotate a generator to obtain power.

Water turbine generators are roughly classified into a vertical axis type in which the generator shaft is installed in the vertical direction and a horizontal axis type in which the generator shaft is installed in the horizontal direction, depending on the structure of the water turbine.

FIG. 6 is a side sectional view showing a configuration example of a conventional horizontal axis water turbine generator.

In the horizontal shaft type water turbine generator 10 illustrated in FIG. 6, the rotary shaft 12 has an impeller 16 of the water turbine 14, a rotor 20 of the generator 18, a rotor 24 of the exciter 22, and an electromagnetic brake 26 as heavy objects. A brake ring 28 or the like is attached, and the rotary shaft 12 is supported by two bearings 30 and 50.

Of the two bearings 30 and 50, the one arranged between the turbine 14 and the generator 18 is the turbine side bearing 30, and the one arranged between the generator 18 and the brake ring 28 is the anti-turbine side bearing. It is called 50.

Inside the bearings 30 and 50, journal bearings that receive a load in the radial direction of the rotating shaft 12 (hereinafter, also referred to as “radial load”) are built-in.

The bearings 30 and 50 also include a storage tank for storing lubricating oil for bearing lubrication. The bearing 30 also includes an oil cooler 34 for cooling the lubricating oil.

The turbine 14 illustrated in FIG. 6 is the most common turbine called a Francis turbine. The impeller 16 is installed in a casing for taking in water, and the impeller 16 is generated by the pressure of water flowing toward the discharge pipe 80. To get power by rotating.

Due to the structure of the reaction turbine represented by this type of Francis turbine, a large force, Thrustka T, is generated in the axial direction of the generator 18 due to water pressure. In order to limit the axial movement of the rotating shaft 12, a thrust bearing that supports the axial load generated by the thruster T (hereinafter, also referred to as “thrust load”) is required.

In order to make the entire horizontal shaft type water turbine generator 10 compact, the thrust bearing is generally arranged in the same bearing as the journal bearing, that is, the water turbine side bearing 30.

FIG. 7A is a side sectional view showing a configuration example of a conventional water turbine side bearing.

FIG. 7B is a cross-sectional view taken along the line AA in FIG. 7A.

In the water turbine side bearing 30, it is necessary to pump the lubricating oil in the storage tank 32 to supply the thrust bearing 31 during operation.

Since the thrust bearing 31 is located at a position higher than the liquid level L of the storage tank 32, the lubricating oil is lifted by the viscous pump 33 in order to fill the thrust bearing 31 with the lubricating oil. A member called a viscous pump fixing portion 33b that forms a groove facing the thrust collar 33a is arranged around the thrust collar 33a that is a rotating portion of the viscous pump 33, and the lower end of the thrust collar 33a is a storage tank 32. Soaked in the lubricating oil inside.

As shown in FIG. 7B, the rotation of the thrust collar 33a realizes a viscous pump 33 in which the lubricating oil rises in the groove portion, that is, the viscous pump fixing portion 33b, due to the viscosity of the lubricating oil.

FIG. 8A is a conceptual diagram showing a pumping path of the lubricating oil in the bearing on the water turbine side.

As shown in FIG. 7B, the lubricating oil of the storage tank 32 in the turbine side bearing 30 is taken in from the viscous pump suction port 33c by the rotation of the rotary shaft 12, and is pumped to the viscous pump discharge port 33d by the action of the viscous pump 33. Then, as shown in FIG. 8A, the pump is sent to a heat exchanger 46 such as an oil cooler provided outside the turbine side bearing 30.

In the heat exchanger 46, the lubricating oil is cooled by the electric blower 47 and then returned to the water wheel side bearing 30, and as shown in FIG. 7A, from the bearing oil supply port 35 in the middle of the thrust bearing 31, inside the holder 41. Lubrication is pumped to the thrust bearing 31 and the journal bearing 36 through the lubrication path.

The lubricating oil is then lubricated from the thrust bearing 31, heated by frictional heat, and then discharged to the storage tank 32 from the oil drain port 37 provided at a position higher than the top of the thrust bearing 31 and the journal bearing 36. ..

Further, the lubricating oil that lubricates the journal bearing 36 and is heated by the frictional heat passes through the oil disc refueling hole 38 and is discharged from the oil disc refueling port 39 during steady operation.

Further, the oil disc lubrication port 39 is used for initial lubrication to lubricate the journal bearing 36 with the lubricating oil scooped up by the oil disc 40 until the journal bearing 36 is lubricated by pressure feeding by the viscous pump 33 at the initial stage of operation. It's a mouth.

The holder 41 holds the thrust bearing 31, the journal bearing 36, and the viscous pump rotating portion 33a, and forms a lubricating oil path. The holder 41 is supported by being sandwiched from above and below by a support (not shown) fixed in the storage tank 32 and the cover 42. The contact surface between the support and the holder 41 is spherically processed so that it can follow the displacement of the shaft during operation.

The journal bearing 36 of the water wheel side bearing 30 is provided with an oil disc 40 for initial lubrication until the lubricating oil is supplied by the viscous pump 33, and the oil disc 40 rotates to lubricate the storage tank 32. Raise the oil to the journal bearing 36.

FIG. 8B is a conceptual diagram showing a pumping path of the lubricating oil in the anti-turbine side bearing.

As shown in FIG. 8B, the anti-turbine side bearing 50 does not have a thrust bearing, but has only a journal bearing 56 built-in. As described above, since the anti-water turbine side bearing 50 has only the journal bearing 56 built-in, it can be sufficiently cooled only by the surface of the general storage tank 52. However, in the anti-turbine side bearing 50, the rotating shaft 12 has a high axial peripheral speed, and a bearing with a large bearing load generates a large amount of heat due to friction, so that sufficient heat cannot be dissipated only on the surface of the storage tank 52. Therefore, the lubricating oil in the storage tank 52 is pressure-fed to a heat exchanger 76 such as an oil cooler provided outside the anti-water turbine side bearing 50, cooled by, for example, an electric blower 77, and then again on the anti-water turbine side. It is necessary to lubricate the bearing 50.

Therefore, it is necessary to similarly mount the viscous pump 53 on the anti-water turbine side bearing 50 to circulate the lubricating oil from the storage tank 52 → the heat exchanger 76 → the journal bearing 56 → the storage tank 52.

Japanese Unexamined Patent Publication No. 2-238178

However, in the case of the above-mentioned conventional bearing structure, there are the following two problems as the speed and size of the water turbine generator increase.

The first problem is that the water turbine side bearing 30 and the anti-water turbine side bearing 50 are provided with heat exchangers 46 and 76, respectively, which causes an increase in the installation area.

The second problem is that since the turbine side bearing 30 and the anti-turbine side bearing 50 have viscous pumps 33 and 53, respectively, axial power for driving the viscous pumps 33 and 53, respectively, is required. Since the shaft power converted into electricity is reduced, the power generation efficiency is reduced.

The present invention has been made in view of such circumstances, and even when the speed and size of the water turbine generator are increased, the increase in the installation area is suppressed and the power generation efficiency is also lowered. Is to provide a bearing structure without.

The bearing structure of the embodiment includes a first bearing and a second bearing that support the rotating shaft of the water turbine generator, and a cooling material provided in the first bearing and provided for cooling the first bearing. A transfer unit for transferring the bearing from the inside of the first bearing to the outside and a cooling unit for cooling the cooling material transferred by the transfer unit are provided, and the cooling material cooled by the cooling unit is the first bearing and the second bearing. The cooling material supplied to both the first bearing and the second bearing for cooling the bearing of the second bearing and used for cooling the second bearing is transferred to the first bearing and is transferred to the first bearing. It merges with the cooling material provided for cooling the bearings.

FIG. 1 is a lubricating oil route diagram for explaining a configuration example of a bearing structure of a water turbine generator according to an embodiment of the present invention. FIG. 2 is a diagram showing an example of an entry / exit route of lubricating oil to a holder in a bearing on a turbine side. FIG. 3A is a front view showing a configuration example of the thrust bearing in the present embodiment. FIG. 3B is a cross-sectional view taken along the line AA in FIG. 3A. FIG. 3C is a cross-sectional view taken along the line BB in FIG. 3A. FIG. 4 is a diagram showing an inflow / outflow route of lubricating oil to a holder in a bearing on a turbine side according to an embodiment of the present invention. FIG. 5 is a conceptual diagram showing a configuration example of the oil box. FIG. 6 is a side sectional view showing a configuration example of a conventional horizontal axis water turbine generator. FIG. 7A is a side sectional view showing a configuration example of a conventional water turbine side bearing. FIG. 7B is a cross-sectional view taken along the line AA in FIG. 7A. FIG. 8A is a conceptual diagram showing a pumping path of the lubricating oil in the bearing on the water turbine side. FIG. 8B is a conceptual diagram showing a pumping path of the lubricating oil in the anti-turbine side bearing.

Hereinafter, the bearing structure of the water turbine generator according to the embodiment of the present invention will be described with reference to the drawings.

In the following embodiments, the same parts as those already described will be indicated by the same reference numerals, and duplicate explanations will be avoided.

FIG. 1 is a lubricating oil route diagram for explaining a configuration example of a bearing structure of a water turbine generator according to an embodiment of the present invention.

That is, the bearing structure for the horizontal axis type water turbine generator according to the embodiment of the present invention is the first bearing (hereinafter referred to as "water turbine side bearing") 30 that supports the rotary shaft 12 of the horizontal axis type water turbine generator. And a second bearing (hereinafter referred to as "anti-turbine side bearing") 50 is provided.

The water wheel side bearing 30 stores the lubricating oil stored in the storage tank 32 and the storage tank 32 used for cooling the thrust bearing 31 and the journal bearing 36 in the water wheel side bearing 30 on the water wheel side. A viscous pump 33, which is a transfer unit for pumping from the inside of the bearing 30 to the outside, is provided inside.

An oil cooler 34, which is a cooling unit for cooling the lubricating oil transferred by the viscous pump 33, is provided outside the water turbine side bearing 30. The oil cooler 34 includes a heat exchanger 46 and an electric blower 47. Lubricating oil is transferred to the heat exchanger 46 by the viscous pump 33. The lubricating oil transferred to the heat exchanger 46 is air-cooled by the cooling air from the electric blower 47.

The lubricating oil cooled in the heat exchanger 46 in this way is branched by the branch portion C provided on the return pipe H ₀ from the heat exchanger 46, so that the water wheel side bearing 30 and the anti-water wheel side bearing 30 are branched. Supplied to both with 50. That is, a part of the lubricating oil cooled in the heat exchanger 46 is transferred from the branch portion C to the anti-turbine _side bearing 50 via the pipe H2 by the driving force of the viscous pump 33, and the rest is transferred. It is transferred from the branch portion C to the turbine _side bearing 30 via the pipe H1.

Thereby, the lubricating oil is provided for cooling the journal bearing 56 in the anti-turbine side bearing 50. Further, the water turbine side bearing 30 is used for cooling the thrust bearing 31 and the journal bearing 36.

The anti-water turbine side bearing 50 includes a storage tank 52 for storing the lubricating oil used for cooling the journal bearing 56.

Further, in the bearing structure of the water turbine generator according to the embodiment of the present invention, the lubricating oil pressure-fed to the heat exchanger 46 is pumped from the branch portion C to the heat exchanger 46 by using the viscous pump 33 in the water turbine _side bearing 30 via the pipe H2. The following measures have been taken so that the bearing 50 on the anti-turbine side can be supplied satisfactorily.

FIG. 2 is a diagram showing an example of an entry / exit route of lubricating oil to a holder in a bearing on a turbine side.

FIG. 3A is a front view showing a configuration example of a thrust bearing.

FIG. 3B is a cross-sectional view taken along the line AA in FIG. 3A.

FIG. 3C is a cross-sectional view taken along the line BB in FIG. 3A.

The lubricating oil that has cooled the thrust bearing 31 is drained from the outer peripheral portion of the thrust bearing 31. At this time, the lubricating oil is subjected to work in the circumferential direction by the rotation of the rotating shaft 12, and is pushed out from the inner peripheral portion of the thrust bearing 31 to the outer peripheral portion by the centrifugal force. Due to this effect, the inner diameter side (also referred to as “inner peripheral side”) of the thrust bearing 31 becomes a negative pressure.

Therefore, the pressure P ₃ on the inner diameter side of the thrust bearing 31 is lower than the internal pressure P ₄ of the pipe H ₂ to the anti-turbine side bearing 50 (P ₃ <P ₄ ), and the anti-turbine side bearing 50 is lubricated. The oil cannot be transferred.

This effect increases as the peripheral speed of the thrust collar 33a increases.

In order to prevent this, as shown in FIGS. 3A and 3B, lubricating oil that cools the thrust bearing 31 is applied to the outer peripheral side of the thrust bearing abutment 44 provided between the thrust bearings 31 to support the thrust bearing 31. An oil passage hole 48 is provided on the inner peripheral side of the thrust bearing, that is, on the opposite side of the sliding surface to allow the lubricating oil to escape.

As shown in FIG. 3C, the lubricating oil that has passed through the oil passage hole 48 is sent to the outside of the thrust bearing 31 and to the inner peripheral side of the thrust bearing 31, and is re-cooled to cool the thrust bearing 31. It is circulated.

FIG. 4 is a diagram showing an inflow / outflow route of lubricating oil to a holder in a bearing on a turbine side according to an embodiment of the present invention.

Lubricating oil that has been subjected to work in the circumferential direction by turning the thrust collar 33a, which is a rotating portion, collides with the holder 41 at the outer peripheral portion, and the static pressure increases. As a result, as shown in FIG. 4, the lubricating oil passes from the oil passage hole 48 of the thrust bearing abutment 44 to the back side. A part of the lubricating oil that has passed through the groove on the back side of the thrust bearing abutment 44 is discharged to the outside of the holder 41, and a part of the lubricating oil is sent to the inner peripheral portion of the thrust bearing 31. As a result, it is possible to prevent the phenomenon (P ₃ <P ₄ ) in which the inner peripheral portion of the thrust bearing becomes a negative pressure as described with reference to FIG. 2, and realize P ₃ > P ₄ . Therefore, a part of the lubricating oil from the heat exchanger 46 is surely pumped to the anti-turbine _side bearing 50 via the pipe H2.

Further, since the amount of oil passing between the thrust bearings 31 becomes uniform due to the oil passage holes 48 between the thrust bearings 31, the cooling effect on the thrust bearings 31 becomes uniform.

An oil box 60 is provided between the storage tank 52 and the storage tank 32.

FIG. 5 is a conceptual diagram showing a configuration example of the oil box.

The oil box 60 includes a weir 61 formed by a pipe H ₄ connected to the lower side of the storage tank 52 and a pipe H ₅ connected to the storage tank 32, and the storage tank 52 and the storage tank 32 are separated from each other. There is.

Further, the weir 61 keeps the liquid level L1 of the lubricating oil in the storage tank 52 sufficiently higher _than the liquid level _L2 of the lubricating oil in the storage tank 32. That is, the oil box 60 is a liquid level maintaining unit that maintains the liquid level L ₁ of the lubricating oil in the storage tank 52 so as to be sufficiently higher than the liquid level L ₂ of the lubricating oil in the storage tank 32.

With such a configuration, the lubricating oil can be transferred from the storage tank 52 to the storage tank 32 by gravity, and the lubricating oil that has reached the oil box 60 from the storage tank 52 via the pipe _H4 overflows the weir 61. , It is transferred to the storage tank 32 via the pipe _H5 without backflow. As a result, the lubricating oil from the storage tank 52 merges with the lubricating oil provided for cooling the thrust bearing 31 and the journal bearing 36 in the storage tank 32.

With such a configuration of the oil box 60, the lower side of the pipe H ₅ becomes the liquid phase (oil phase), and the upper side of the H ₅ becomes the gas phase (air). By making the height of the uppermost part of the weir 61 the same as the liquid level L ₁ of the storage tank 52, the liquid level of the pipe H ₅ can be made the same as the liquid level L ₂ of the storage tank 32.

By the way, as shown in FIG. 1, the pipe H ₂ to the anti-turbine side bearing 50 is longer than the pipe H ₁ to the water turbine side bearing 30. Therefore, in the pipe H2, the _volume of air accumulated at rest is also large. The air in the pipe H ₂ is pushed out to the anti-water turbine side bearing 50 together with the lubricating oil at the initial stage of operation. This air becomes bubbles G and accumulates on the surface of the storage tank 52.

Bubbles G generated at the initial stage of operation fall into the storage tank 52 together with the lubricating oil. As a result, the bubbles G accumulate on the upper side of the storage tank 52 and eventually disappear. As a result, only the lubricating oil at the lower part of the storage tank 52 without bubbles G flows into the oil box 60 through the pipe _H4 , overflows the weir 61, and then flows into the storage tank 32. As a result, the bubbles G generated in the anti-turbine side bearing 50 do not enter the storage tank 32.

If the bubbles G enter the storage tank 32 and are sucked into the viscous pump 33, the bubbles G become fine and difficult to disappear, and as a result, the discharge amount of the viscous pump 33 is reduced. Then, as described above, since the lubricating oil not accompanied by the bubbles G is transferred to the storage tank 32, the discharge amount of the viscous pump 33 is not reduced.

As described above, according to the bearing structure of the present embodiment, the heat coolers conventionally installed in both the water turbine side bearing 30 and the anti-water turbine side bearing 50 can be shared by one heat cooler. , Does not increase the installation area.

Along with this, the viscous pump 33, which has been conventionally installed in both the turbine side bearing 30 and the anti-turbine side bearing 50, needs to be provided only in the turbine side bearing 30, so that the viscous pump 33 can be driven. The shaft power can also be reduced, the reduction of the shaft power converted into electricity can be suppressed, and the reduction of power generation efficiency can be suppressed.

Although some embodiments of the present invention have been described, these embodiments are presented as examples and are not intended to limit the scope of the invention. These embodiments can be implemented in various other embodiments, and various omissions, replacements, and changes can be made without departing from the gist of the invention. These embodiments and variations thereof are included in the scope of the invention described in the claims and the equivalent scope thereof, as are included in the scope and gist of the invention.

10 Horizontal axis type water wheel generator 12 Rotating shaft 14 Water wheel 16 Impeller 18 Generator 20 Rotator 22 Exciter 24 Rotator 26 Electromagnetic brake 28 Brake ring 30 Water wheel side bearing 31 Thrust bearing 32 Storage tank 33 Viscous pump 33a Thrust collar 33b Viscous Pump fixing part 33c Viscous pump suction port 33d Viscous pump discharge port 34 Oil cooler 35 Bearing refueling port 36 Journal bearing 37 Oil drain port 38 Oil disc refueling hole 39 Oil disc refueling port 40 Oil disc 41 Holder 42 Cover 44 Thrust bearing Abutment 46 Heat exchanger 47 Electric blower 48 Oil passage hole 50 Anti-water wheel side bearing 52 Storage tank 53 Viscous pump 56 Journal bearing 60 Oil box 61 Dam 76 Heat exchanger 77 Electric blower 80 Discharge pipe

The bearing structure of the embodiment includes a first bearing and a second bearing that support the rotating shaft of the water turbine generator, and a cooling material provided in the first bearing and provided for cooling the first bearing. A transfer unit for transferring the bearing from the inside of the first bearing to the outside and a cooling unit for cooling the cooling material transferred by the transfer unit are provided, and the cooling material cooled by the cooling unit is the first bearing and the second bearing. The cooling material supplied to both the first bearing and the second bearing for cooling the bearing of the second bearing and used for cooling the second bearing is transferred to the first bearing and is transferred to the first bearing. The first bearing is a water wheel side bearing and the second bearing is an anti-water wheel side bearing, which is merged with the cooling material provided for cooling the bearing.

The bearing structure of the embodiment includes a first bearing and a second bearing that support the rotating shaft of the water turbine generator, and a cooling material provided in the first bearing and provided for cooling the first bearing. A transfer unit that transfers the bearing from the inside of the first bearing to the outside, and a cooling unit that is a transfer destination of all the cooling materials transferred by the transfer unit and cools the cooling material, and is cooled by the cooling unit. The material was supplied to both the first bearing and the second bearing for cooling the first bearing and the second bearing, and the cooling material provided for cooling the second bearing was It is transferred to the first bearing and merged with the cooling material provided for cooling the first bearing, the first bearing is the water wheel side bearing and the second bearing is the anti-water wheel side bearing. ..

Claims (8)

A bearing structure for a water turbine generator
The first bearing and the second bearing that support the rotating shaft of the water turbine generator, and
A transfer unit for transferring the coolant provided in the first bearing and used for cooling the first bearing from the inside of the first bearing to the outside.
A cooling unit for cooling the coolant transferred by the transfer unit is provided.
The coolant cooled by the cooling unit is supplied to both the first bearing and the second bearing for cooling the first bearing and the second bearing.
A bearing structure in which the coolant used for cooling the second bearing is transferred to the first bearing and merged with the coolant used for cooling the first bearing. The first bearing and the second bearing each include a storage tank for storing the cooling material provided for cooling, and the liquid level of the cooling material in the storage tank of the second bearing. By raising the liquid level of the cooling material in the storage tank of the first bearing higher than the liquid level of the cooling material, the cooling material is transferred from the storage tank of the second bearing to the storage tank of the first bearing by gravity. The bearing structure according to claim 1, which enables this. The bearing according to claim 2, further comprising a liquid level maintaining portion for maintaining the liquid level of the cooling material in the storage tank of the second bearing higher than the liquid level of the cooling material in the storage tank of the first bearing. structure. The bearing structure according to any one of claims 1 to 3, wherein a part of the coolant cooled by the cooling unit is transferred into the second bearing by the driving force of the transfer unit. .. The bearing structure according to any one of claims 1 to 4, wherein the coolant is a lubricating oil for rotating the rotating shaft. The bearing structure according to any one of claims 1 to 5, wherein the first bearing is a water wheel side bearing, and the second bearing is an anti-water wheel side bearing. The first bearing comprises a thrust bearing and
The thrust bearing abutment that supports the thrust bearing is provided with a conduction hole that guides the cooling material that has cooled the thrust bearing to the inner peripheral side of the thrust bearing.
The cooling material that has cooled the thrust bearing is partially guided to the inner peripheral side of the thrust bearing through the conduction hole, passes through the inner peripheral side of the thrust bearing, and then cools the thrust bearing. The bearing structure according to claim 6, which is recirculated for the purpose of. A first pipe for guiding the coolant cooled by the cooling unit to the first bearing and a second pipe for guiding the coolant to the second bearing are provided.
The bearing structure according to claim 7, wherein the pressure in the first pipe is made higher than the pressure in the second pipe by the recirculation.

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