JP6832177B2 - Hydro power generator - Google Patents

Description

The present invention relates to a hydropower generator.

Conventionally, there is known a technique related to a water flow power generation device that generates electricity by using the energy of the water flow (ocean current, tidal current, river flow) of the sea or a river. For example, Patent Document 1 discloses a power generation device including a floating pressure vessel and a rotor assembly to which blades are connected, and including a power pod that generates power when the blades are driven by a water stream. In this hydropower device, the rotor assembly is rotatably supported by a fluid bearing with respect to the floating pressure vessel.

Special Table 2014-534375

In the hydropower generator described in Patent Document 1, a floating tail cone (buoyancy material) for adding buoyancy to a power pod is attached to an end portion of the rotor assembly opposite to the floating pressure vessel. By attaching the buoyancy material to the rotor assembly in this way, the underwater weight of the exposed portion of the rotor assembly exposed to water is reduced, and the load applied to the bearing is reduced. However, depending on the position of the center of gravity and the buoyancy of the exposed part of the rotor assembly, the moment acting on the exposed part becomes large due to the weight and buoyancy of the exposed part, and the rotor assembly maintains a posture parallel to the axial direction. It may not be possible. As a result, one-sided contact occurs on the bearing surface of the bearing that supports the rotor assembly, and the wear of the bearing surface is accelerated.

The present invention has been made in view of the above, and an object of the present invention is to provide an underwater power generation device capable of suppressing wear of a bearing that supports a rotating portion that rotates by the force of a water flow.

In order to solve the above-mentioned problems and achieve the object, the present invention is a water flow power generation device that generates power by the force of the water flow, has a blade that rotates by the force of the water flow, and rotates integrally with the blade. A rotating portion, a power generation unit connected to the rotating portion and generating power by the rotational force of the rotating portion, a space covering the power generation unit and arranging the power generation unit, and underwater in which the blade is arranged. The rotation is provided with a nacelle that serves as a boundary and has an air atmosphere in the space where the power generation unit is arranged, and a journal bearing that rotatably supports the rotating portion with respect to the nacelle in the radial direction of the rotating portion. When a moment acts on the exposed part exposed to water outside the nacelle due to the weight at the center of gravity and the buoyancy at the buoyancy, one end of the journal bearing receives a reaction force from the nacelle and the other end. The reaction force received from the nacelle is characterized in that the ratio of the larger one to the smaller one is 1.5 or less.

In the water flow power generator according to the present invention, when a moment acts on the exposed portion due to the weight at the center of gravity and the buoyancy at the buoyancy center, the reaction force and the nacelle received from the nacelle by one end of the journal bearing that supports the rotating portion in the radial direction. Of the reaction forces received by the other end, the ratio of the larger one to the smaller one is 1.5 or less. As a result, the reaction force received from the nacelle at one end and the other end of the journal bearing can be made uniform, and it is possible to suppress the occurrence of one-sided contact with the bearing surface of the journal bearing and the local increase in surface pressure. Therefore, according to the water flow power generation device according to the present invention, it is possible to suppress the wear of the bearing that supports the rotating portion that rotates by the force of the water flow.

Further, it is preferable that the exposed portion of the rotating portion has a plurality of buoyant materials provided so as to sandwich the center of gravity in the axial direction of the rotating portion. As a result, the buoyancy acting on the exposed portion can be made uniform on both sides in the axial direction of the center of gravity, so that the buoyancy of the exposed portion can be brought closer to the center of gravity. As a result, the moment acting on the exposed portion can be easily adjusted to be small by the weight at the center of gravity and the buoyancy at the buoyancy, so that the reaction force received by one end of the journal bearing and the reaction force received by the other end , It becomes easy to set the ratio of the larger one to the smaller one to 1.5 or less.

Further, the exposed portion of the rotating portion has a bottom portion and a tubular side wall portion extending in the axial direction from the bottom portion toward the nacelle side and to which the blades are connected, and the plurality of buoyancy members. Preferably has a first buoyancy material attached to the bottom portion and a second buoyancy material attached to the side wall portion. This makes it easier to place the second buoyancy material on the opposite side of the first buoyancy material with the center of gravity of the exposed portion in between, utilizing the axial length of the tubular portion to which the blades are connected. That is, a plurality of buoyancy members can be relatively easily provided at positions sandwiching the center of gravity in the axial direction.

Further, it is preferable to include a tubular buoyancy material that accommodates a portion of the rotating portion other than the plurality of blades of the exposed portion. As a result, the buoyancy acting on the exposed portion can be made uniform on both sides in the axial direction of the center of gravity of the exposed portion, so that the buoyancy of the exposed portion can be brought closer to the center of gravity.

The water flow power generation device according to the present invention has an effect that wear of a bearing supporting a rotating portion that rotates by the force of a water flow can be suppressed.

FIG. 1 is a schematic configuration diagram showing an example of a hydroelectric power generation device according to an embodiment. FIG. 2 is a schematic view showing an example of a hydroelectric power generation device according to the present embodiment. FIG. 3 is an enlarged cross-sectional view showing the vicinity of the exposed portion of the rotor of the water flow power generator. FIG. 4 is an enlarged cross-sectional view showing the vicinity of the exposed portion of the rotor of the hydropower generator as a comparative example. FIG. 5 is an enlarged cross-sectional view showing the vicinity of the exposed portion of the rotor of the hydropower generator as a comparative example. FIG. 6 is a perspective view showing a water flow power generation device according to a modified example.

Hereinafter, embodiments of the hydroelectric power generation device according to the present invention will be described in detail with reference to the drawings. The present invention is not limited to this embodiment.

FIG. 1 is a schematic configuration diagram showing an example of a water flow power generation device according to an embodiment, and FIG. 2 is a schematic diagram showing an example of a water flow power generation device according to the present embodiment. The water flow power generation device 1 according to the embodiment is arranged in water and generates power with water flow energy. The water current power generation device 1 is arranged in the sea, for example, and generates electricity with ocean current energy or tidal current energy. The water flow power generation device 1 may be arranged in a river and generate power with river flow energy.

The water flow power generator 1 is arranged in an internal space of a rotor (rotating portion) 14 including a rotor head 3 provided with a plurality of blades 2, a stator 15 including a nacelle 7 that rotatably supports the rotor 14, and an internal space of the nacelle 7. It is provided with a drive train 8 connected to the rotor head 3 and a generator 9 arranged in the internal space of the nacelle 7 and generating electricity by the rotational energy of the rotor 14 transmitted via the drive train 8. The drive train 8 and the generator 9 form a power generation unit 11 that generates electricity by the rotational force of the rotor 14.

In the present embodiment, the water flow power generation device 1 is an underwater floating type water flow power generation device 1. As shown in FIG. 1, the hydroelectric power generation device 1 is moored to the seabed via a cable (mooring measure) 10. The internal space of the nacelle 7 is filled with a gas such as air, and the space in which the power generation unit 11 is arranged is used as an air atmosphere. A plurality of blades 2 are attached to the rotor head 3. When an ocean current hits the blade 2, the rotor head 3 rotates with the ocean current energy acting on the blade 2. The rotational energy (rotational torque) of the rotor 14 is transmitted to the generator 9 via the drive train 8 via the rotating shaft 4. The generator 9 generates electricity by the rotational energy of the rotor 14 transmitted via the drive train 8. The rotating shaft 4 is fixed to the rotor head 3 and rotates together with the rotor head 3 to which the blade 2 is connected.

The rotating shaft 4 is inserted inside the nacelle 7. Further, the rotating shaft 4 has a portion on the rotor head 3 side (first rotating portion) and a portion inserted inside the nacelle 7 (second rotating portion). The first rotating portion and the second rotating portion may be connected by a coupling (not shown). In the water flow power generation device 1, a plurality of (two in this embodiment) journal bearings 5 and a plurality of (two in this embodiment) thrust bearings 6 are arranged between the rotor head 3 and the nacelle 7. The rotor head 3 is rotatably supported by the nacelle 7.

In the hydropower generator 1, a seal bearing 19 is arranged between the rotating shaft 4 and the nacelle 7. In the seal bearing 19, the fixed portion is fixed to the nacelle 7, the rotating portion is fixed to the rotating shaft 4, and the rotating shaft 4 and the nacelle 7 are supported while being rotatable between the rotating shaft 4 and the nacelle 7. It seals between. As a result, the hydroelectric power generation device 1 can suppress the inflow of seawater into the nacelle 7 from the portion where the rotating shaft 4 of the nacelle 7 is inserted. As a result, the nacelle 7 becomes a boundary between the space where the power generation unit 11 is arranged and the water where the blade 2 is arranged. Further, a portion of the rotor 14 that is arranged outside the nacelle 7 with a position where the rotating shaft 4 is supported by the seal bearing 19 is a boundary becomes an exposed portion 141 of the rotor 14 that is exposed to water.

The electric power generated by the generator 9 is sent to the ground via a power transmission cable. Since the underwater floating type hydroelectric power generation device 1 is suspended in the sea by the cable 10, it has an advantage that it is not easily affected by wind and waves.

In this embodiment, the drive train 8 is a hydraulic drive train. The drive train 8 includes a brake 80 connected to the rotating shaft 4, a hydraulic pump 81 connected to the rotating shaft 4, a hydraulic motor 82 operated by the hydraulic pump 81, pipes 83 and 84, and a cooling unit 85. Is equipped with. The hydropower generator 1 may include the rotating shaft 4 in the drive train 8. The brake 80 is driven when the rotation of the blade 2 is stopped. The brake 80 stops the rotation of the rotor 14 such as the blade 2 by fixing the rotating shaft 4 so that it does not rotate. The hydraulic pump 81 pressurizes and discharges the hydraulic oil by the rotation of the rotating shaft 4. The hydraulic motor 82 rotates the rotor 14 with the high-pressure hydraulic oil supplied. The pipe 83 connects the oil discharge port of the hydraulic pump 81 and the oil suction port of the hydraulic motor 82. The pipe 84 connects the oil discharge port of the hydraulic motor 82 and the oil suction port of the hydraulic pump 81. The hydraulic oil of the drive train 8 can flow through the pipe 83 and the pipe 84. The cooling unit 85 is provided in the pipe 84 and cools the hydraulic oil supplied from the hydraulic motor 82 to the hydraulic pump 81. In the drive train 8, when the rotor head 3 rotates, the rotation shaft 4 also rotates. The hydraulic pump 81 is operated by the rotational energy of the rotor head 3 transmitted via the rotating shaft 4. The hydraulic pump 81 supplies hydraulic oil to the hydraulic motor 82 to drive the hydraulic motor 82. The hydraulic motor 82 operates the generator 9. The cooling unit 85 may pressurize and supply water as a lubricating fluid to the journal bearing 5 and the thrust bearing 6, which will be described later. The drive train 8 may have any configuration as long as the rotational force of the rotating shaft 4 can be transmitted to the generator 9.

Next, the support structure of the rotor 14 with respect to the nacelle 7 will be described. In the following description, the axial direction of the rotating shaft 4 is referred to as "axial direction", and the radial direction of the rotating shaft 4 is referred to as "diameter direction".

As shown in FIG. 2, the rotor head 3 has a bottom portion 31 to which the rotating shaft 4 is connected at the center, and a tubular side wall portion 32 extending in the axial direction from the outer edge portion of the bottom portion 31 so as to surround the rotating shaft 4. .. The side wall portion 32 has a large diameter portion 321 connected to the bottom portion 31 and a blade connecting portion 322 connected to the large diameter portion 321. The blade connecting portion 322 protrudes radially outward from one end of the rotor side tubular portion 322a having a diameter smaller than that of the large diameter portion 321 and the rotor side tubular portion 322a in the axial direction, and is connected to the large diameter portion 321. It has a rotor-side flange portion 322b and a second rotor-side flange portion 322c that protrudes radially outward from the other end of the rotor-side tubular portion 322a in the axial direction. In the rotor side tubular portion 322a, a plurality of blades 2 are connected to the outer peripheral surface of a substantially central portion in the axial direction at intervals in the circumferential direction.

Further, the nacelle 7 has a rotor support portion 70 that surrounds the rotating shaft 4 and extends in the axial direction to support the rotor 14. The rotor support portion 70 is formed to be one size larger than the blade connecting portion 322 along the shape of the blade connecting portion 322 provided on the side wall portion 32 of the rotor head 3. The rotor support portion 70 includes a stator-side tubular portion 70a extending in the axial direction, a first stator-side flange portion 70b protruding radially outward from one end of the stator-side tubular portion 70a in the axial direction, and a stator-side tubular portion. It has a second stator-side flange portion 70c that protrudes radially outward from the other end in the axial direction of 70a.

As shown in FIG. 2, in the water flow power generation device 1, the rotor side tubular portion 322a of the blade connecting portion 322 provided on the side wall portion 32 of the rotor head 3 and the stator side of the rotor support portion 70 provided on the nacelle 7. Two journal bearings 5 are arranged between the tubular portion 70a and the tubular portion 70a. Further, in the hydroelectric power generation device 1, a thrust bearing 6 is arranged between the first rotor side flange portion 322b of the blade connecting portion 322 and the first stator side flange portion 70b of the rotor support portion 70. Further, in the hydroelectric power generation device 1, a thrust bearing 6 is arranged between the second rotor side flange portion 322c of the blade connecting portion 322 and the second stator side flange portion 70c of the rotor support portion 70.

As a result, the rotor 14 is rotatably supported with respect to the nacelle 7 in the radial direction by the two journal bearings 5, and rotatably supported with respect to the nacelle 7 in the axial direction by the two thrust bearings 6. In this way, among the rotor heads 3, the blade connecting portion 322 to which the plurality of blades 2 are connected is supported with respect to the nacelle 7 by the journal bearing 5 and the thrust bearing 6, whereby the rotor 14 is stably supported. Rotational shake of the rotor 14 can be suppressed. In the present embodiment, the journal bearing 5 and the thrust bearing 6 are water-lubricated bearings, and are lubricated by seawater obtained from the periphery of the rotor head 3. As described above, the water flow power generation device 1 may pressurize and supply seawater as a lubricating fluid from the cooling unit 85 to the journal bearing 5 and the thrust bearing 6.

Next, a plurality of buoyancy members 40 attached to the rotor 14 will be described. FIG. 3 is an enlarged cross-sectional view showing the vicinity of the exposed portion of the rotor of the hydroelectric power generation device. As shown in the figure, the exposed portion 141 of the rotor 14 has a plurality of buoyancy members 40 provided with the center of gravity 141W of the exposed portion 141 interposed therebetween in the axial direction. The plurality of buoyancy materials 40 include a first buoyancy material 41 and a second buoyancy material 42. The first buoyancy material 41 and the second buoyancy material 42 are made of a low-density material, and impart buoyancy to the exposed portion 141 of the rotor 14.

The first buoyancy member 41 is attached to the surface of the bottom 31 of the rotor head 3 opposite to the nacelle 7. The first buoyancy member 41 is provided on the side opposite to the nacelle 7 from the center of gravity 141W of the exposed portion 141. The second buoyancy member 42 is attached to the outer peripheral surface of the rotor side tubular portion 322a of the blade connecting portion 322 provided on the side wall portion 32 of the rotor head 3. The second buoyancy member 42 is provided on the nacelle 7 side of the center of gravity 141W of the exposed portion 141. That is, the first buoyancy material 41 and the second buoyancy material 42 are provided so as to sandwich the center of gravity 141W of the exposed portion 141 in the axial direction. In the present embodiment, as shown in FIG. 2, the second buoyancy member 42 is attached to the outer peripheral surface of the rotor side tubular portion 322a over the entire circumference while avoiding the attachment portions of the plurality of blades 2. The second buoyancy member 42 may be attached only to a part of the outer peripheral surface of the rotor side tubular portion 322a.

As a result, the underwater weight of the exposed portion 141 of the rotor 14 (the weight obtained by subtracting the buoyancy acting in water from the weight in the air) can be reduced, and the load applied to the journal bearing 5 and the thrust bearing 6 can be reduced. It will be possible. In the present embodiment, since the exposed portion 141 of the rotor 14 is formed in a vertically symmetrical structure, the floating center 141B and the center of gravity 141W of the exposed portion 141 are arranged at positions aligned in the vertical direction as shown in FIG. Will be done. By providing the first buoyancy material 41 and the second buoyancy material 42 so as to sandwich the center of gravity 141W of the exposed portion 141 in the axial direction, the buoyancy acting on the exposed portion 141 of the rotor 14 is uniform on both sides of the center of gravity 141W in the axial direction. Can be achieved. That is, the floating center 141B of the exposed portion 141 can be brought closer to the center of gravity 141W.

As shown in FIG. 3, the distance from the center 5a of the two journal bearings 5 in the axial direction to the center of gravity 141W of the exposed portion 141 is set to “Lw”, and the floating center 141B of the exposed portion 141 from the center 5a of the two journal bearings 5 is defined as “Lw”. Let "Lb" be the distance from the center 5a of the two journal bearings 5 to "Lj" at one end 51 and the other end 52. One end 51 and the other end 52 indicate one end and the other end in the axial direction when the two journal bearings 5 are considered as an integral bearing. Further, the radial reaction force that one end 51 of the journal bearing 5 receives from the rotor support 70 of the nacelle 7 is set to "F1", and the other end 52 of the journal bearing 5 receives the radial reaction from the rotor support 70 of the nacelle 7. Let the force be "F2". Here, the reaction forces received by the two journal bearings 5 from the nacelle 7 are integrated into one end 51 and the other end 52.

Assuming that the upward force in the vertical direction is positive, the following equation (1) is established from the balance of the forces in the vertical direction acting on the exposed portion 141. Further, it is assumed that the weight W of the exposed portion 141 at the center of gravity 141W and the buoyancy B at the buoyancy center 141B cause a moment M in the counterclockwise direction in the drawing to act around the center 5a of the journal bearing 5. Assuming that the moment M in the counterclockwise direction in the figure is positive, the following equation (2) is established from the balance of the moment acting on the journal bearing 5. Equations (1) and (2) are based on the assumption that both the reaction force F1 and the reaction force F2 are upward in the vertical direction. Based on the equations (1) and (2), the reaction force F1 received by one end 51 of the journal bearing 5 is calculated by the following equation (3), and the reaction force F2 received by the other end 52 of the journal bearing 5 is as follows. It is calculated by the formula (4).

F1 + F2-W + B = 0 ... (1)
M-Lj ・ F1 + Lj ・ F2 = 0 ・ ・ ・ (2)
F1 = (WB) / 2+ (M / Lj) / 2 ... (3)
F2 = (WB) /2- (M / Lj) / 2 ... (4)

When the moment M is positive (counterclockwise in the figure), the reaction force F1 calculated by the equation (3) becomes a positive value, and as shown by the solid arrow in FIG. 3, one end 51 of the journal bearing 5 It is a vertical upward force acting on the upper surface in the figure of. When the moment M is positive (counterclockwise in the figure), the reaction force F2 calculated by the equation (4) becomes a negative value, and as shown by the solid arrow in FIG. 3, the journal bearing 5 It is a vertical downward force acting on the lower surface of the other end 52 in the figure. At this time, the journal bearing 5 has a one-sided contact with the bearing surface on the side receiving the reaction force F1 and the reaction force F2.

From the equations (3) and (4), it can be seen that the values of the reaction force F1 and the reaction force F2 become closer to each other as the moment M becomes smaller. If the moment M has a value of 0, the reaction force F1 and the reaction force F2 have the same direction and the same value, and one-sided contact does not occur on the bearing surface of the journal bearing 5. The smaller the value of the moment M and the closer the values of the reaction force F1 and the reaction force F2 are, the smaller the one-sided contact generated on the bearing surface of the journal bearing 5. The moment M is calculated by the following equation (5). From the equation (5), the value of the moment M can be easily adjusted as the distance between the center of gravity 141W and the floating center 141W of the exposed portion 141 is closer, that is, the closer the distance Lw and the distance Lb are. Understand. That is, the closer the distance Lw and the distance Lb are, the greater the degree to which the difference between the weight W and the buoyancy B of the exposed portion 141 contributes to the magnitude of the moment M, and therefore the difference between the weight W and the buoyancy B. It becomes easy to adjust the moment M to be small by adjusting.

M = Lb ・ B-Lw ・ W ・ ・ ・ (5)

As described above, in the hydroelectric power generation device 1 according to the present embodiment, the floating center 141B of the exposed portion 141 can be brought close to the center of gravity 141W. Therefore, in the hydroelectric power generation device 1 according to the present embodiment, the moment M calculated by the equation (5) can be easily reduced, and the reaction force F1 calculated by the equations (3) and (4) and the reaction force F1 and The value of the reaction force F2 can be easily brought close to each other. In FIG. 3, since the buoyancy center 141B and the center of gravity 141W are shown, the buoyancy center 141B and the center of gravity 141W are shown relatively far apart, but the closer the buoyancy center 141B and the center of gravity 141W are, the more preferable. It is more preferable that the positions of the buoyancy center 141B and the center of gravity 141W match.

Here, if the larger one of the reaction force F1 and the reaction force F2 is the reaction force Fbig and the smaller one is the reaction force Fsmal, the reaction force Fbig with respect to the reaction force Fsmall in the hydropower generator 1 according to the present embodiment. The ratio is 1.5 or less as shown in the following equation (6). In this way, by bringing the values of the reaction force F1 and the reaction force F2 close to each other and setting the ratio of the reaction force Fbig to the reaction force Fsmal to 1.5 or less, one-sided contact occurs on the bearing surface of the journal bearing 5 and is locally localized. It is possible to suppress an increase in surface pressure. The smaller the ratio of the reaction force Fbig to the reaction force Fsmall, the more preferable.

Fbig / Fsmal ≤ 1.5 ... (6)

Here, the reaction forces received by the two journal bearings 5 from the nacelle 7 are integrated into one end 51 and the other end 52, but the journal bearing 5 has a reaction force of a distributed load from the nacelle 7 along the axial direction. Receive. In the formula (6), the ratio of the reaction force Fbig to the reaction force Fsmall is 1.5 or less based on the force obtained by consolidating the reaction forces received from the nacelle 7 by the two journal bearings 5 at one end 51 and the other end 52. Of the reaction forces of the distributed load received by the two journal bearings 5 from the nacelle 7, the forces received at one end 51 and the other end 52 are considered as a reference.

4 and 5 are enlarged cross-sectional views showing the vicinity of the exposed portion of the rotor of the hydropower generator as a comparative example. The water flow power generation device 1A as a comparative example includes a buoyancy material 40A instead of the first buoyancy material 41 of the water flow power generation device 1 according to the embodiment. Further, the water flow power generation device 1A as a comparative example does not include the second buoyancy material 42 of the water flow power generation device 1 according to the embodiment. Since the other configurations of the water flow power generation device 1A are the same as those of the water flow power generation device 1, the description thereof will be omitted.

The buoyancy material 40A is attached to the bottom 31 of the rotor head 3 in the same manner as the first buoyancy material 41. Further, as shown in FIG. 4, the buoyancy material 40A is larger than the first buoyancy material 41. As a result, the magnitude of the buoyancy B acting on the exposed portion 141 of the rotor 14 of the hydropower generator 1A as a comparative example is the magnitude of the buoyancy B acting on the exposed portion 141 of the rotor 14 of the hydropower generator 1 according to the embodiment. Is the same as. Further, in the water flow power generation device 1A as a comparative example, the weight W of the exposed portion 141 is the same as the weight W of the exposed portion 141 of the water flow power generation device 1 according to the embodiment.

Since the exposed portion 141 of the rotor 14 of the hydroelectric power generation device 1A as a comparative example does not include the second buoyancy material 42, it is larger than the buoyancy center 141B (see FIG. 3) of the exposed portion 141 of the hydroelectric power generation device 1 according to the embodiment. , The buoyancy center 141B is arranged at a position separated from the center of gravity 141W in the axial direction. That is, as shown in FIG. 4, the distance Lw from the center 5a of the journal bearing 5 in the axial direction to the center of gravity 141W of the exposed portion 141 and the distance Lw from the center 5a of the two journal bearings 5 to the floating center 141B of the exposed portion 141. The difference from Lb becomes large. As a result, from the equation (5), the water flow power generation device 1A as a comparative example has a larger moment M value than the water flow power generation device 1 according to the embodiment. Therefore, in the hydropower generator 1A as a comparative example, the ratio of the larger reaction force Fbig to the smaller reaction force Fsmal of the reaction force F1 and the reaction force F2 is larger than that of the hydropower generator 1 according to the embodiment. growing. In the water flow power generator 1A as a comparative example, as shown in the range surrounded by the broken line in FIG. 5, the one-sided contact generated on the bearing surfaces of the journal bearing 5 and the thrust bearing 6 becomes large, and the wear of the bearing surface is uneven. At the same time, the wear is accelerated. Note that FIG. 5 shows that the degree of inclination of the entire rotor 14 with respect to the axial direction is made larger than the actual one in order to explain that the one-sided contact generated on the bearing surfaces of the journal bearing 5 and the thrust bearing 6 becomes large.

On the other hand, in the hydroelectric power generation device 1 according to the embodiment, as described above, the values of the reaction force F1 and the reaction force F2 can be easily brought close to each other by bringing the floating center 141B of the exposed portion 141 closer to the center of gravity 141W. Further, the ratio of the larger one (reaction force Fbig) to the smaller one (reaction force Fsmal) of the reaction force F1 and the reaction force F2 is 1.5 or less. As a result, it is possible to suppress one-sided contact that occurs on the bearing surface of the journal bearing 5 as compared with the water flow power generation device 1A of the comparative example. Further, as for the thrust bearing 6, similarly, it is possible to suppress the one-sided contact that occurs on the bearing surface.

As described above, the water flow generator 1 according to the embodiment supports the rotor 14 in the radial direction when the moment M acts on the exposed portion 141 due to the weight W at the center of gravity 141W and the buoyancy B at the buoyancy 141B. Of the reaction force F1 received by one end 51 of the journal bearing 5 from the nacelle 7 and the reaction force F2 received by the other end 52 from the nacelle 7, the ratio of the larger one (reaction force Fbig) to the smaller one (reaction force Fsmal) is 1. It is less than 5.5. As a result, the reaction forces F1 and F2 received from the nacelle 7 at one end 51 and the other end 52 of the journal bearing 5 are made uniform, and the bearing surface of the journal bearing 5 is hit by one side to locally increase the surface pressure. It becomes possible to suppress. Therefore, according to the water flow power generation device 1 according to the present embodiment, it is possible to suppress the wear of the bearing supporting the rotating portion that rotates by the force of the water flow.

Further, the exposed portion 141 of the rotor 14 has a plurality of buoyancy members 40 provided with a center of gravity 141W interposed therebetween in the axial direction of the rotor 14. As a result, the buoyancy acting on the exposed portion 141 can be made uniform on both sides of the center of gravity 141W in the axial direction, so that the buoyancy 141B of the exposed portion 141 can be brought closer to the center of gravity 141W. As a result, the moment M acting on the exposed portion 141 can be easily adjusted to be small by the weight W at the center of gravity 141W and the buoyancy B at the buoyancy 141B, so that the reaction force F1 received by one end 51 of the journal bearing 5 Of the reaction force F2 received by the other end 52, the ratio of the larger one (reaction force Fbig) to the smaller one (reaction force Fsmal) can be easily set to 1.5 or less.

Further, the exposed portion 141 of the rotor 14 has a bottom portion 31 and a tubular side wall portion 32 extending axially from the bottom portion 31 toward the nacelle 7 side and to which the blades 2 are connected, and a plurality of buoyancy members 40. Has a first buoyancy member 41 attached to the bottom portion 31 and a second buoyancy member 42 attached to the side wall portion 32. As a result, it is easy to arrange the second buoyancy member 42 on the opposite side of the first buoyancy member 41 with the center of gravity 141W of the exposed portion 141 interposed therebetween by utilizing the axial length of the tubular side wall portion 32 to which the blade 2 is connected. Become. That is, the plurality of buoyancy members 40 can be relatively easily provided at positions sandwiching the center of gravity 141W in the axial direction.

In the present embodiment, the first buoyancy member 41 is attached to the bottom portion 31 of the rotor head 3, and the second buoyancy member 42 is attached to the rotor side tubular portion 322a of the blade connecting portion 322 provided on the side wall portion 32 of the rotor head 3. However, the arrangement positions of the first buoyancy material 41 and the second buoyancy material 42 are not limited to this. For example, the second buoyancy material 42 may be attached to the plurality of blades 2 themselves, or the second buoyancy material 42 may be arranged inside the plurality of blades 2.

Further, in the present embodiment, the plurality of buoyancy materials 40 have the first buoyancy material 41 and the second buoyancy material 42, but the plurality of buoyancy materials 40 have three or more buoyancy materials. You may.

Further, the hydroelectric power generation device 1 may include only one buoyancy material. FIG. 6 is a perspective view showing a water flow power generation device according to a modified example. In FIG. 6, the mooring line is not shown. The water flow power generation device 1B according to the modified example has a buoyancy material 40B instead of the first buoyancy material 41 and the second buoyancy material 42 of the water flow power generation device 1. Since the other configurations of the water flow power generation device 1B are the same as those of the water flow power generation device 1, the description thereof will be omitted. As shown in the figure, the buoyancy member 40B is a tubular member that accommodates a plurality of exposed portions 141 other than the blades 2. As a result, the buoyancy acting on the exposed portion 141 can be made uniform on both sides of the center of gravity 141W in the axial direction, so that the buoyancy 141B of the exposed portion 141 can be brought closer to the center of gravity 141W.

Further, in the present embodiment, the rotor side tubular portion 322a of the blade connecting portion 322 provided on the side wall portion 32 of the rotor head 3 and the stator side tubular portion 70a of the rotor support portion 70 provided on the nacelle 7. Although two journal bearings 5 are arranged between them, at least one journal bearing 5 may be arranged, and three or more journal bearings 5 may be arranged in between. Further, in the present embodiment, the journal bearing 5 and the thrust bearing 6 are used as separate members, but the adjacent journal bearing 5 and the thrust bearing 6 may be configured as an integral member. Further, at least one of the journal bearing 5 and the thrust bearing 6 may be an oil-lubricated bearing arranged in the internal space of the nacelle 7.

1, 1A, 1B Hydraulic power generator 2 Blade 3 Rotor head 31 Bottom 32 Side wall 321 Large diameter 322 Blade connection 322a Rotor side tubular part 322b First rotor side flange part 322c Second rotor side flange part 4 Rotating shaft 5 Radial bearing 5a Center 51 One end 52 Other end 6 Journal bearing 7 Nacelle 70 Rotor support 70a Stator side tubular part 70b First stator side flange part 70c Second stator side flange part 8 Drive train 9 Generator 10 Cable 11 Power generation unit 14 Rotor 141 Exposed part 141B Floating center 141W Center of gravity 15 Stator 19 Seal bearing 40, 40A, 40B Floating material 41 First buoyant material 42 Second buoyant material 80 Brake 81 Hydraulic pump 82 Hydraulic motor 83, 84 Piping 85 Cooling unit

Claims (4)

It is a water flow power generation device that generates electricity with the power of water flow.
A rotating portion having a blade that rotates by the force of the water flow and rotating integrally with the blade,
A power generation unit that is connected to the rotating part and generates power by the rotational force of the rotating part,
A nacelle that covers the power generation unit, serves as a boundary between the space in which the power generation unit is arranged and the water in which the blade is arranged, and creates an air atmosphere in the space in which the power generation unit is arranged.
A journal bearing that rotatably supports the rotating portion with respect to the nacelle in the radial direction of the rotating portion.
A buoyancy material arranged in an exposed portion of the rotating portion exposed to water outside the nacelle is provided.
Before Symbol Exposure unit, when the moment by the buoyancy in the center of buoyancy of the weight and the exposed portion of the center of gravity of the exposed portion is applied, the reaction force and the other one end of the journal bearing receives from the nacelle is the A water flow power generator characterized in that the ratio of the larger reaction force received from the nacelle to the smaller one is 1.5 or less. The buoyant material, the exposed portion of the rotary unit, the water flow generator according to claim 1, characterized in that it comprises a plurality of buoyant material provided across the center of gravity in the axial direction of the rotating portion. The exposed portion of the rotating portion has a bottom portion and a tubular side wall portion extending in the axial direction from the bottom portion toward the nacelle side and to which the blades are connected.
The water flow power generation device according to claim 2, wherein the plurality of buoyancy materials include a first buoyancy material attached to the bottom portion and a second buoyancy material attached to the side wall portion. The buoyant material is water generator according to claim 1, characterized in that it comprises a cylindrical buoyancy member which houses a plurality of portions other than the blades of the exposed portion of the rotating portion.

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