Bearing device for hydraulic machine and hydraulic machine

Abstract

To suppress wear of a main bearing caused by foreign matter contained in river water while suppressing an increase in manufacturing cost.SOLUTION: A bearing device for a hydraulic machine comprises: a main bearing that is provided on the outer periphery of a main shaft and supports the main shaft; an upper water tank containing the main bearing and lubrication water in which the main bearing is immersed; a lower water tank positioned closer to a runner than the upper water tank, allowing some of river water used for rotationally driving the runner to flow into it; and a main shaft water sealing part that is provided at a position between the lower water tank and the runner and forms a clearance for flowing of the river water between the outer periphery of the main shaft and the main shaft water sealing part, thereby reducing a flow rate of the river water flowing into the lower water tank. The lower water tank separates foreign matter from the river water that flows in through the clearance in the main shaft water sealing part by means of a swirling component of the river water generated by rotation of the main shaft. The upper water tank stores the river water from which foreign matter is separated in the lower tank, as the lubrication water.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] FIELD OF THE INVENTION An embodiment of the present invention relates to a bearing device for a hydraulic machine and a hydraulic machine. [Background technology]

[0002] A bearing device for a hydraulic machine is known, which is used in a hydraulic machine having a runner and a main shaft connected to the runner. The bearing device includes a main bearing mounted on the outer periphery of the main shaft of the hydraulic machine and a bearing fluid tank containing a lubricant such as water or oil for immersing the main bearing. The main bearing supports the main shaft by receiving a load acting in the radial direction of the main shaft within the bearing fluid tank. In recent years, due to environmental considerations and from the perspective of avoiding environmental pollution caused by oil leakage, there has been an increasing demand for bearing devices that use river water as a lubricant for the main bearing.

[0003] However, because river water contains foreign matter such as sediment, there is a risk that the foreign matter will cause wear to the main bearings if river water is used as a lubricant for the main bearings. One way to address this is to use ceramics or other materials that are highly resistant to wear and tear against foreign matter as the main bearing material, but this method risks increasing manufacturing costs. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Publication No. 8-338428 Summary of the Invention [Problem to be solved by the invention]

[0005] The present invention has been made taking these points into consideration, and aims to provide a bearing device for a hydraulic machine and a hydraulic machine that can suppress wear of the main bearing due to foreign matter contained in river water while suppressing increases in manufacturing costs. [Means for solving the problem]

[0006] A bearing device for a hydraulic machine according to an embodiment is used in a hydraulic machine having a runner that is rotationally driven by inflowing river water and a main shaft that rotates with the rotation of the runner. The bearing device for a hydraulic machine includes: a main bearing mounted on the outer periphery of the main shaft to support the main shaft; an upper water tank that accommodates the main bearing and a lubricant that immerses the main bearing; a lower water tank that is located closer to the runner than the upper water tank and into which a portion of the river water that drives the runner flows; and a main shaft water seal that is located between the lower water tank and the runner and forms a gap between the outer periphery of the main shaft and through which the river water flows, thereby reducing the flow rate of the river water that flows into the lower water tank. The lower water tank separates foreign matter from the river water that flows in through the gap in the main shaft water seal by using a swirling component of the river water generated by the rotation of the main shaft. The upper water tank contains the river water from which foreign matter has been separated in the lower water tank as a lubricant.

[0007] Moreover, the hydraulic machine according to the embodiment includes a runner that is rotationally driven by inflowing river water, a main shaft that rotates with the rotation of the runner, and the above-mentioned bearing device. [Effects of the Invention]

[0008] According to this embodiment, it is possible to suppress wear of the main bearing due to foreign matter contained in river water while suppressing an increase in manufacturing costs. [Brief explanation of the drawings]

[0009] [Figure 1] FIG. 1 is a meridian cross-sectional view of a vertical shaft Francis turbine according to a first embodiment. [Figure 2] FIG. 2 is a front cross-sectional view of the bearing device according to the first embodiment. [Figure 3] FIG. 3 is a diagram showing the relationship between the water level of the bearing water tank and the water level of the lower pond shown in FIG. [Figure 4] FIG. 4 is a front cross-sectional view of a bearing device according to the second embodiment. [Figure 5] FIG. 5 is a view of the foreign object dropping member shown in FIG. 4 as seen from below. [Figure 6] FIG. 6 is a front cross-sectional view of a bearing device according to a third embodiment. [Figure 7] FIG. 7 is a view of the foreign matter inflow prevention member shown in FIG. 6 as viewed from below. DETAILED DESCRIPTION OF THE INVENTION

[0010] Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

[0011] (First embodiment) A bearing device for a hydraulic machine and a hydraulic machine according to a first embodiment will be described with reference to Figures 1 to 3. First, a vertical shaft Francis turbine, which is an example of a hydraulic machine, will be described with reference to Figure 1.

[0012] As shown in FIG. 1, the vertical shaft Francis turbine 1 includes a casing 2, a plurality of stay vanes 3, a plurality of guide vanes 4, and a runner 5.

[0013] The casing 2 is formed in a spiral shape. When the turbine is in operation, river water W flows into the casing 2 from an upper reservoir where the river water W is stored through a penstock (neither of which is shown), and the inflowing river water W flows inside the casing 2. Here, the river water W may contain foreign matter such as sediment.

[0014] The stay vanes 3 are components for guiding the river water W that has flowed into the casing 2 to the guide vanes 4 and the runner 5. A plurality of stay vanes 3 are arranged at predetermined intervals in the circumferential direction. A flow path through which the river water W flows is formed between the stay vanes 3.

[0015] The guide vanes 4 are components for guiding the inflowing river water W to the runner 5. A plurality of guide vanes 4 are arranged at predetermined intervals in the circumferential direction. A flow path through which the river water W flows is formed between the guide vanes 4. Each guide vane 4 is configured to be rotatable, and by rotating each guide vane 4 to change the opening degree, the flow rate of the river water W flowing into the runner 5 can be adjusted. In this way, the amount of power generated by the generator 7, which will be described later, can be adjusted.

[0016] The runner 5 is configured to be rotatable about a rotation axis X relative to the casing 2. The runner 5 is rotationally driven by river water W flowing in from the casing 2 during turbine operation. In other words, the runner 5 is a member for converting the pressure energy of the river water W flowing into the runner 5 into rotational energy.

[0017] The runner 5 has a crown 5a connected to the main shaft 6 (described later), a band 5b provided on the outer periphery of the crown 5a, and a plurality of runner blades 5c provided between the crown 5a and the band 5b. The plurality of runner blades 5c are arranged at predetermined intervals in the circumferential direction. A flow path through which river water W flows is formed between the runner blades 5c.

[0018] A main shaft 6 is connected to the runner 5. As the runner 5 rotates, the main shaft 6 rotates about a rotation axis X extending in the vertical direction. The main shaft 6 extends in a direction along the rotation axis X. In the following description, the direction along the rotation axis X of the main shaft 6 will also be referred to as the axial direction, the radial direction of the main shaft 6 as the radial direction, and the rotation direction of the main shaft 6 as the circumferential direction.

[0019] A generator 7 is connected to the main shaft 6. The generator 7 is configured to generate electricity by receiving rotational energy from the runner 5 when the turbine is in operation.

[0020] The generator 7 may also function as an electric motor, and may be configured to rotate the runner 5 when supplied with electric power. In this case, water can be sucked up from the lower reservoir through the draft pipe 8 and discharged into the upper reservoir, enabling the vertical Francis turbine 1 to operate as a pump turbine (pumping operation). In this case, the opening of the guide vanes 4 is changed so that the amount of water pumped is appropriate depending on the pump head.

[0021] A draft pipe 8 is provided downstream of the runner 5 when the turbine is in operation. The draft pipe 8 is connected to a lower reservoir 9 (see Figure 3), and the river water W that rotates the runner 5 recovers pressure and is released into the lower reservoir 9.

[0022] As shown in Fig. 2, an upper cover 10 is provided above the crown 5a of the runner 5. A back pressure chamber 11 is provided between the crown 5a and the upper cover 10. A portion of the river water W that drives the runner 5 to rotate when the turbine is in operation flows into the back pressure chamber 11. The river water W that flows into this back pressure chamber 11 is supplied to a bearing water tank 40 of the bearing device 20, which will be described later.

[0023] Next, a bearing device 20 for a hydraulic machine according to this embodiment (hereinafter simply referred to as the bearing device 20) will be described with reference to FIGS.

[0024] The bearing device 20 is a device for supporting the main shaft 6 connected to the runner 5. The bearing device 20 according to this embodiment uses river water W as a lubricant for the main shaft 6. As shown in FIG. 2 , the bearing device 20 includes a main bearing 30, a bearing water tank 40, and a main shaft water seal unit 50.

[0025] Main bearing 30 is provided on the outer periphery of main shaft 6. Main bearing 30 supports main shaft 6 by receiving a load acting in the radial direction of main shaft 6. The inner circumferential surface of main bearing 30 faces the outer circumferential surface of main shaft 6. A gap is provided between the inner circumferential surface of main bearing 30 and the outer circumferential surface of main shaft 6. Main bearing 30 is formed in a segmental shape, and multiple main bearings 30 are arranged in the circumferential direction. However, this is not a limitation, and main bearing 30 may be formed in a cylindrical shape and provided around the entire outer periphery of main shaft 6 in the circumferential direction.

[0026] A bearing support base 32 is provided radially outward from the main bearing 30. An adjustment unit 33 is attached to the bearing support base 32 for adjusting the radial position of the main bearing 30. The adjustment unit 33 has an adjustment bolt 33a and an adjustment nut 33b. The adjustment bolt 33a is threadedly engaged with the bearing support base 32 and fixed by the adjustment nut 33b. The radially inner end of the adjustment bolt 33a abuts against the outer circumferential surface of the main bearing 30, pressing the main bearing 30 radially inward. The radial position of the main bearing 30 can be adjusted by adjusting the amount that the adjustment bolt 33a is threaded into the bearing support base 32. A support plate 34 extends radially inward from the lower part of the bearing support base 32 and supports the main bearing 30 from below. The bearing support base 32 is connected to a tank body 41 of a bearing water tank 40 (described later) via a connecting member 35 and is supported by the tank body 41.

[0027] The bearing water tank 40 is provided around the main bearing 30. The bearing water tank 40 covers the main bearing 30. The bearing water tank 40 contains river water W, which is lubricating water for the main bearing 30. The tank body 41 has a bottom plate 41a, a top plate 41b, a side plate 41c, an axial partition plate 41d (partition plate), and a radial partition plate 41e.

[0028] The bottom plate 41a forms the bottom of the bearing water tank 40. The bottom plate 41a is provided at a lower position in the axial direction of the bearing water tank 40. The bottom plate 41a may be configured as a separate member from the top plate 41b, the side plates 41c, the axial partition plate 41d, and the radial partition plate 41e. The bottom plate 41a may be supported by a support member 10a extending from the upper cover 10. The bottom plate 41a may be formed in the shape of a thin circular ring concentric with the main shaft 6 so that the main shaft 6 passes inside. The diameter of the inner peripheral portion of the bottom plate 41a is larger than the diameter of the main shaft 6. Therefore, a gap is provided between the inner peripheral portion of the bottom plate 41a and the outer peripheral surface of the main shaft 6.

[0029] The top plate 41b forms the ceiling of the bearing water tank 40. The top plate 41b is provided at an upper position in the axial direction of the bearing water tank 40. The top plate 41b may be configured as a separate body from the bottom plate 41a, the side plates 41c, the axial partition plates 41d, and the radial partition plates 41e. The top plate 41b may be attached to the upper part of the side plates 41c. The top plate 41b may be formed in the shape of a thin circular ring concentric with the main shaft 6 so that the main shaft 6 passes inside. The diameter of the inner peripheral part of the top plate 41b is larger than the diameter of the main shaft 6. Therefore, a gap is provided between the inner peripheral part of the top plate 41b and the outer peripheral surface of the main shaft 6.

[0030] The side plate 41c constitutes the side of the bearing water tank 40. The side plate 41c is provided at a radially outer position of the bearing water tank 40. The side plate 41c may be formed in a cylindrical shape concentric with the main shaft 6 so that the main shaft 6 and main bearing 30 are located inside. The inner peripheral surface of the side plate 41c faces the outer peripheral surface of the main shaft 6.

[0031] The axial partition plate 41d is provided so as to extend radially inward from the side plate 41c. The axial partition plate 41d may be attached to the side plate 41c. The axial partition plate 41d may be formed in the shape of a thin annular plate concentric with the main shaft 6 so that the main shaft 6 passes inside. The diameter of the outer periphery of the axial partition plate 41d is equal to the diameter of the inner periphery of the side plate 41c. The diameter of the inner periphery of the axial partition plate 41d is larger than the diameter of the main shaft 6. Therefore, a gap is provided between the inner periphery of the axial partition plate 41d and the outer periphery of the main shaft 6. The axial partition plate 41d axially divides the interior of the bearing water tank 40 into an upper water tank 42 (described later) and a lower water tank 43 (described later).

[0032] The radial partition plate 41e is provided at a position radially inward of the side plate 41c. The radial partition plate 41e is provided at a position axially lower than the axial partition plate 41d. That is, the radial partition plate 41e is provided in a lower water tank 43 (described later). The radial partition plate 41e may be provided at a position radially outward of the bottom plate 41a. The radial partition plate 41e may be supported by a support member 10a extending from the upper cover 10. The radial partition plate 41e may be formed in the shape of a hollow truncated cone concentric with the main shaft 6. The radial partition plate 41e may be inclined so that its inner diameter increases from bottom to top in the axial direction. The radial partition plate 41e radially divides the interior of the bearing water tank 40. More specifically, the radial partition plate 41e radially divides the interior of the lower water tank 43. As a result, inside the lower water tank 43, a foreign matter collecting section 44, which will be described later, is provided between the radial partition plate 41e and the side plate 41c.

[0033] The bearing water tank 40 includes an upper water tank 42 and a lower water tank 43. The interior of the bearing water tank 40 is divided into the upper water tank 42 and the lower water tank 43 in the axial direction by the axial partition plate 41d described above.

[0034] The upper water tank 42 is provided above the bearing water tank 40 in the axial direction. The upper water tank 42 contains the main bearing 30 and river water W. The upper water tank 42 may contain the bearing support base 32, adjustment unit 33, support plate 34, and connecting member 35 described above, in addition to the main bearing 30. The upper water tank 42 contains river water W as lubricating water for the main bearing 30. More specifically, the upper water tank 42 contains the river water W from which foreign matter has been separated in the lower water tank 43 (described below), as lubricating water for the main bearing 30. The upper water tank 42 contains the river water W so as to submerge the main bearing 30. Note that the river water W does not need to submerge the entire main bearing 30; it is sufficient that at least a portion of the main bearing 30 is submerged. The river water W flows from the lower water tank 43 through the gap between the axial partition plate 41d and the main shaft 6 and into the upper water tank 42.

[0035] The lower water tank 43 is provided at a position below the bearing water tank 40 in the axial direction. In other words, the lower water tank 43 is provided at a position closer to the runner 5 than the upper water tank 42. The lower water tank 43 stores river water W. A portion of the river water W that rotates the runner 5 flows into the lower water tank 43. The river water W flows from the back pressure chamber 11 through a gap in the main shaft water seal section 50, which will be described later, and into the lower water tank 43. More specifically, the river water W that has passed through the gap in the main shaft water seal section 50 flows into the lower water tank 43 through a gap between the inner peripheral part of the bottom plate 41a and the outer peripheral surface of the main shaft 6.

[0036] Here, the river water W that has flowed into the lower water tank 43 has a swirling component. That is, while the river water W flows through the gap of the main shaft water seal portion 50, a swirling component that moves radially outward is imparted to the river water W by the rotation of the main shaft 6. Therefore, foreign matter contained in the river water W that has flowed into the lower water tank 43 moves radially outward of the lower water tank 43 while swirling in the circumferential direction due to the swirling component of the river water W that is generated by the rotation of the main shaft 6. In this way, the lower water tank 43 separates foreign matter from the river water W that has flowed in after passing through the gap of the main shaft water seal portion 50 by the swirling component of the river water W that is generated by the rotation of the main shaft 6.

[0037] The lower water tank 43 may have a foreign matter collection section 44 that collects foreign matter contained in the river water W. The foreign matter collection section 44 is provided at a radially outer position of the lower water tank 43. The foreign matter collection section 44 is provided between the radial partition plate 41e and the side plate 41c. As described above, the radial partition plate 41e is inclined so that the inner diameter increases from the bottom to the top in the axial direction. This allows the river water W that flows into the lower water tank 43 to maintain a swirling component on the radial partition plate 41e. Therefore, the foreign matter contained in the river water W rides the flow of the river water W, swirls circumferentially along the radial partition plate 41e, and heads radially outward, and is guided to the foreign matter collection section 44. In this way, the foreign matter contained in the river water W is collected in the foreign matter collection section 44.

[0038] The lower water tank 43 may have a discharge section 44a that discharges the foreign matter collected in the foreign matter collection section 44 to the outside together with the river water W. The discharge section 44a may be provided at the bottom of the foreign matter collection section 44. A discharge device 44b may be connected to the discharge section 44a. The discharge device 44b may be installed outside the bearing water tank 40. The discharge device 44b is configured to discharge the foreign matter and river water W from the discharge section 44a at predetermined time intervals. For example, the discharge device 44b may be controlled by a timer to discharge a fixed amount of river water W from the foreign matter collection section 44 at predetermined time intervals. The discharge device 44b may be, for example, a strainer.

[0039] A filter 44c may also be provided to capture foreign matter discharged from the discharge section 44a. The filter 44c may be provided between the discharge device 44b and an inlet section 44d (described later). The filter 44c may be provided in a position close to the inlet section 44d (described later). The foreign matter discharged from the discharge section 44a by the discharge device 44b may be discharged to the outside. On the other hand, the river water W discharged from the discharge section 44a by the discharge device 44b may pass through the filter 44c and be supplied again to the lower water tank 43. The river water W is filtered by passing through the filter 44c. In other words, the filter 44c captures foreign matter contained in the river water W. The lower water tank 43 may have an inlet section 44d that allows the river water W discharged from the discharge section 44a and passed through the filter 44c to flow back into the lower water tank 43. The inlet section 44d may be provided on a side plate 41c that defines the foreign matter collection section 44.

[0040] Furthermore, an impeller 45 that rotates together with the main shaft 6 may be provided in the lower water tank 43. The impeller 45 may be attached to the outer peripheral surface of the main shaft 6. The impeller 45 rotates within the lower water tank 43. The impeller 45 may be provided in the lower water tank 43 at a position close to the outlet of the main shaft water seal section 50. The impeller 45 may be provided close to the bottom plate 41a. In this embodiment, one impeller 45 is provided in the lower water tank 43.

[0041] The impeller 45 has an impeller body 45a and a plurality of impeller blades 45b. The impeller body 45a may be formed in a cylindrical shape concentric with the main shaft 6. The inner peripheral surface of the impeller body 45a faces the outer peripheral surface of the main shaft 6. The impeller body 45a is attached to the outer peripheral surface of the main shaft 6 so that the inner peripheral surface of the impeller body 45a contacts the outer peripheral surface of the main shaft 6. The diameter of the inner peripheral surface of the impeller body 45a is equal to the diameter of the main shaft 6. The impeller blades 45b are attached radially to the outer peripheral surface of the impeller body 45a. The impeller blades 45b are arranged at predetermined intervals in the circumferential direction. The diameter of the outer peripheral portion of each impeller blade 45b is smaller than the minimum diameter of the inner peripheral surface of the radial partition plate 41e.

[0042] The centrifugal force caused by the rotation of the impeller 45 further imparts a radially outward swirling component to the river water W that has flowed into the lower water tank 43. Therefore, the centrifugal force caused by the rotation of the impeller 45 allows the lower water tank 43 to more effectively separate foreign matter from the river water W.

[0043] The main shaft water seal unit 50 is provided at a position closer to the runner 5 than the lower water tank 43 of the bearing water tank 40. In other words, the main shaft water seal unit 50 is provided at a position between the lower water tank 43 and the runner 5. The main shaft water seal unit 50 forms a gap between itself and the outer periphery of the main shaft 6, through which river water W flows. The main shaft water seal unit 50 is configured to reduce the flow rate of the river water W flowing into the lower water tank 43. The river water W flows from the back pressure chamber 11 into the gap of the main shaft water seal unit 50, passes through the gap of the main shaft water seal unit 50, and flows into the lower water tank 43.

[0044] The main shaft water sealing unit 50 may have a sleeve 51 and a seal member 52. The sleeve 51 may be formed in a cylindrical shape concentric with the main shaft 6. The inner peripheral surface of the sleeve 51 faces the outer peripheral surface of the main shaft 6. The sleeve 51 is attached to the outer peripheral surface of the main shaft 6 so that the inner peripheral surface of the sleeve 51 contacts the outer peripheral surface of the main shaft 6. The seal member 52 is provided to face the sleeve 51. The seal member 52 may be formed in a substantially cylindrical shape concentric with the main shaft 6. The seal member 52 is supported by a frame portion 53. The above-mentioned gap is formed between the sleeve 51 and the seal member 52. The seal member 52 may have a labyrinth seal structure. That is, the seal member 52 may be configured so that portions where the gap between the sleeve 51 and the seal member 52 is relatively small and portions where the gap between the sleeve 51 and the seal member 52 is relatively large are arranged alternately in the axial direction. With this configuration, the fluid resistance in the gap of the main shaft water seal portion 50 is increased, and the flow rate of the river water W flowing from the back pressure chamber 11 into the lower water tank 43 can be reduced. In addition, while the river water W flows through the gap of the main shaft water seal portion 50, a swirling component is imparted to it by the rotation of the main shaft 6.

[0045] As shown in FIG. 3, during turbine operation, the water level H2 of the lower basin 9 may be equal to or higher than the water level H1 of the bearing sump 40. The water level H1 of the bearing sump 40 shown in FIG. 3 is the same as the water level H1 of the upper basin 42 shown in FIG. 2. The water level H1 of the bearing sump 40 may coincide with the position of the upper end of the main bearing 30. The water level H2 of the lower basin 9 is the water level of the lower basin 9 at which river water W that flows into the runner 5 reaches. If the water level H2 of the lower basin 9 is lower than the water level H1 of the bearing sump 40 during turbine operation, the river water W contained in the bearing sump 40 may flow out toward the runner 5 due to a pressure difference. This may cause the water level H1 of the bearing sump 40 to drop, and the river water W may no longer function as lubricating water. However, by setting the water level H2 of the lower basin 9 to be equal to or higher than the water level H1 of the bearing sump 40, the river water W contained in the bearing sump 40 can be prevented from flowing out toward the runner 5.

[0046] Next, the operation of this embodiment having such a configuration will be described.

[0047] When the vertical Francis turbine 1 according to this embodiment is operated, river water W flows from an upper reservoir (not shown) through the penstock, casing 2, and stay vanes 3 into the guide vanes 4, and then flows from the guide vanes 4 into the runner 5. The river water W that flows into the runner 5 drives the runner 5 to rotate. The rotationally driven runner 5 transmits rotational energy to the generator 7 via the connected main shaft 6, and the generator 7 generates electricity. The river water W that has driven the runner 5 to rotate is discharged from the runner 5 through the draft pipe 8 into the lower reservoir 9.

[0048] A portion of the river water W that rotates and drives the runner 5 flows into a back pressure chamber 11 provided between the crown 5a and the upper cover 10. The river water W in the back pressure chamber 11 flows into the gap in the main shaft water seal portion 50 and flows through the gap in the main shaft water seal portion 50. The river water W that has passed through the gap in the main shaft water seal portion 50 flows into the lower water tank 43 through the gap between the inner peripheral portion of the bottom plate 41a and the outer peripheral surface of the main shaft 6.

[0049] Here, while the river water W flows through the gap of the main shaft water seal portion 50, the rotation of the main shaft 6 imparts a swirling component that moves radially outward. Furthermore, in the lower water tank 43, the impeller 45 rotates as the main shaft 6 rotates. The centrifugal force generated by the rotation of the impeller 45 further imparts a swirling component to the river water W. Therefore, foreign matter contained in the river water W that flows into the lower water tank 43 swirls circumferentially and moves radially outward from the lower water tank 43 due to the swirling component of the river water W generated by the rotation of the main shaft 6. In this manner, the foreign matter is separated from the river water W in the lower water tank 43. Furthermore, the foreign matter contained in the river water W rides the flow of the river water W, swirls circumferentially along the radial partition plate 41e, and moves radially outward, and is guided to the foreign matter collection portion 44. Thus, the foreign matter separated from the river water W is collected in the foreign matter collection portion 44.

[0050] The foreign matter collected in the foreign matter collection section 44 is discharged to the outside from the discharge section 44a together with the river water W. The foreign matter and river water W are discharged at predetermined time intervals by the discharge device 44b. The foreign matter discharged from the discharge section 44a is captured by the filter 44c. The foreign matter captured by the filter 44c is discharged to the outside. Meanwhile, the river water W that has passed through the filter 44c and been filtered flows back into the lower water tank 43 from the inlet section 44d.

[0051] The river water W from which foreign matter has been separated in the lower water tank 43 flows into the upper water tank 42 through the gap between the inner peripheral part of the axial partition plate 41d and the outer peripheral surface of the main shaft 6. In this way, the upper water tank 42 contains the river water W from which foreign matter has been separated in the lower water tank 43 as lubricating water.

[0052] According to this embodiment, the lower water tank 43 separates foreign matter from the river water W that flows in through the gap in the main shaft water seal 50 by using the swirling component of the river water W generated by the rotation of the main shaft 6. The upper water tank 42 stores the river water W from which foreign matter has been separated in the lower water tank 43 as lubricating water for the main bearing 30. This prevents foreign matter from flowing into the upper water tank 42 and prevents foreign matter from being contained in the lubricating water for the main bearing 30. This prevents wear of the main bearing 30 due to foreign matter. This also eliminates the need to use ceramics or other materials that are highly wear-resistant against foreign matter as the material for the main bearing 30. This prevents an increase in manufacturing costs. According to this embodiment, it is possible to prevent wear of the main bearing 30 due to foreign matter contained in the river water W while suppressing an increase in manufacturing costs.

[0053] Furthermore, according to this embodiment, it is possible to eliminate the need to provide main shaft 6 with a main shaft skirt (bearing journal) that faces main bearing 30. In other words, even if main shaft 6 is not provided with a main shaft skirt, it is possible to prevent foreign matter from being contained in the lubricating water for main bearing 30. This allows the weight of main shaft 6 to be reduced. Furthermore, it is possible to reduce the outer diameter of the portion of main shaft 6 that faces main bearing 30, and to reduce the inner diameter of main bearing 30. This allows main bearing 30 to be made smaller.

[0054] Furthermore, according to this embodiment, the lower water tank 43 is provided with an impeller 45 that rotates together with the main shaft 6, and the lower water tank 43 separates foreign matter from the river water W by centrifugal force caused by the rotation of the impeller 45. This makes it possible to more effectively separate foreign matter contained in the river water W. This makes it possible to further prevent foreign matter from flowing into the upper water tank 42, and further prevent wear of the main bearing 30 due to foreign matter.

[0055] Furthermore, according to this embodiment, bearing water tank 40 has an axial partition plate 41d that divides the interior in the axial direction into upper water tank 42 and lower water tank 43. In this way, by dividing the interior of one bearing water tank 40 into upper water tank 42 and lower water tank 43 by axial partition plate 41d, it is possible to prevent the bearing device 20 from becoming larger and the manufacturing costs from increasing.

[0056] Furthermore, according to this embodiment, the lower water tank 43 has a foreign matter collection section 44 provided at a radially outer position, which collects foreign matter contained in the river water W. By collecting the foreign matter in the foreign matter collection section 44 in this way, it is possible to more effectively separate the foreign matter contained in the river water W. This makes it possible to further prevent foreign matter from flowing into the upper water tank 42, and to further prevent wear of the main bearing 30 due to the foreign matter.

[0057] Furthermore, according to this embodiment, the lower water tank 43 has a discharge section 44a that discharges the foreign matter collected in the foreign matter collection section 44 to the outside together with the river water W. By discharging the foreign matter to the outside from the discharge section 44a in this way, it is possible to prevent the foreign matter in the foreign matter collection section 44 from moving radially inward. This makes it possible to further prevent foreign matter from flowing into the upper water tank 42, and further prevent wear of the main bearing 30 due to the foreign matter.

[0058] Furthermore, according to this embodiment, a filter 44c is provided that captures foreign matter discharged from the discharge portion 44a, and the lower water tank 43 has an inlet portion 44d that allows the river water W that has been discharged from the discharge portion 44a and passed through the filter 44c to flow back into the lower water tank 43. In this way, the river water W discharged from the discharge portion 44a is passed through the filter 44c to be filtered, and then allowed to flow back into the lower water tank 43 from the inlet portion 44d, thereby removing foreign matter from the river water W and suppressing fluctuations in the water level H1 of the bearing water tank 40.

[0059] Furthermore, according to this embodiment, a discharge device 44b is provided that discharges foreign matter and river water W from the discharge section 44a at predetermined time intervals. This allows the foreign matter collected in the foreign matter collection section 44 to be automatically discharged to the outside at predetermined time intervals.

[0060] In the above-described embodiment, an example has been described in which one impeller 45 is provided in the lower water tank 43. However, this is not limited to this, and multiple impellers 45 may be provided in the lower water tank 43. The multiple impellers 45 may be attached to the main shaft 6 so as to be aligned in the axial direction. In this case, a larger swirling component can be imparted to the river water W that flows into the lower water tank 43. Therefore, the lower water tank 43 can more effectively separate foreign matter from the river water W by the centrifugal force caused by the rotation of the multiple impellers 45.

[0061] (Second embodiment) Next, a bearing device for a hydraulic machine and a hydraulic machine according to a second embodiment will be described with reference to FIGS.

[0062] The second embodiment shown in Figures 4 and 5 differs mainly in that a foreign object dropping member is provided above the foreign object collection section, protruding from the partition plate and dropping foreign objects toward the foreign object collection section. The other configurations are substantially the same as those of the first embodiment shown in Figures 1 to 3. In Figures 4 and 5, the same parts as those of the first embodiment shown in Figures 1 to 3 are designated by the same reference numerals, and detailed descriptions thereof will be omitted.

[0063] In this embodiment, as shown in FIG. 4, a foreign object falling member 60 is provided above the foreign object collection section 44. The foreign object falling member 60 is provided on the axial partition plate 41d. The foreign object falling member 60 may be attached to the axial partition plate 41d. The foreign object falling member 60 protrudes downward from the axial partition plate 41d. The foreign object falling member 60 may extend in the circumferential direction. As shown in FIGS. 4 and 5, the foreign object falling member 60 may be formed in the shape of a partially annular thin plate. Also, as shown in FIG. 5, multiple foreign object falling members 60 may be arranged at intervals in the circumferential direction. In this case, each foreign object falling member 60 may have end portions 61 provided on both sides in the circumferential direction. The foreign object falling member 60 drops foreign objects toward the foreign object collection section 44. The foreign object falling member 60 may drop foreign objects by colliding with the end portions 61.

[0064] Foreign matter contained in the river water W that has flowed into the lower water tank 43 swirls circumferentially due to a swirling component of the river water W generated by the rotation of the main shaft 6, and moves radially outward from the lower water tank 43. The foreign matter contained in the river water W rides the flow of the river water W, swirls circumferentially along the radial partition plate 41e, and moves radially outward, and is led above the foreign matter collection section 44. The foreign matter led above the foreign matter collection section 44 collides with the foreign matter dropping member 60, particularly the end 61 of the foreign matter dropping member, and falls toward the foreign matter collection section 44.

[0065] As described above, according to this embodiment, a foreign matter dropping member 60 is provided above the foreign matter collection section 44, protruding from the axial partition plate 41d and dropping foreign matter toward the foreign matter collection section 44. This allows foreign matter that has been guided above the foreign matter collection section 44 by the swirling component of the river water W to drop into the foreign matter collection section 44. This allows the foreign matter to be efficiently collected in the foreign matter collection section 44.

[0066] Furthermore, according to this embodiment, the foreign object dropping member 60 is provided on the axial partition plate 41 d, thereby preventing foreign objects from colliding with the axial partition plate 41 d and the side plate 41 c, thereby preventing the axial partition plate 41 d and the side plate 41 c from being worn down by foreign objects.

[0067] (Third embodiment) Next, a bearing device for a hydraulic machine and a hydraulic machine according to a third embodiment will be described with reference to FIGS.

[0068] The third embodiment shown in Figures 6 and 7 differs mainly in that a foreign matter inflow prevention member that protrudes from the partition plate and prevents foreign matter from flowing into the upper water tank is provided at a position closer to the main shaft than the foreign matter collection unit. The other configurations are substantially the same as those of the first embodiment shown in Figures 1 to 3. In Figures 6 and 7, the same parts as those of the first embodiment shown in Figures 1 to 3 are designated by the same reference numerals and detailed description thereof will be omitted.

[0069] In this embodiment, as shown in FIG. 6, the foreign matter inflow suppression member 70 is provided at a position closer to the main shaft 6 than the foreign matter collection section 44. That is, the foreign matter inflow suppression member 70 is provided radially inward of the foreign matter collection section 44. The foreign matter inflow suppression member 70 is provided on the axial partition plate 41d. The foreign matter inflow suppression member 70 may be attached to the axial partition plate 41d. The foreign matter inflow suppression member 70 protrudes downward from the axial partition plate 41d. The foreign matter inflow suppression member 70 may extend in the circumferential direction. As shown in FIGS. 6 and 7, the foreign matter inflow suppression member 70 may be formed in a cylindrical shape. The foreign matter inflow suppression member 70 suppresses foreign matter from flowing into the upper water tank 42.

[0070] Foreign matter contained in the river water W that has flowed into the lower water tank 43 swirls circumferentially due to a swirling component of the river water W generated by the rotation of the main shaft 6, and moves radially outward from the lower water tank 43. The foreign matter contained in the river water W rides the flow of the river water W, swirls circumferentially along the radial partition plate 41e, and moves radially outward, and is guided to the foreign matter collection section 44. Here, as the river water W loses its swirling component, some of the foreign matter contained in the river water W may move radially inward. Furthermore, foreign matter in the foreign matter collection section 44 may move radially inward. In this case, the foreign matter that has moved radially inward may flow from the lower water tank 43 into the upper water tank 42 through the gap between the axial partition plate 41d and the main shaft 6.

[0071] In contrast, according to the present embodiment, foreign matter inflow prevention member 70 is provided at a position closer to main shaft 6 than foreign matter collection section 44, protruding from axial partition plate 41d and preventing foreign matter from flowing into upper water tank 42. This causes foreign matter that has moved radially inward to collide with foreign matter inflow prevention member 70, preventing it from reaching the gap between axial partition plate 41d and main shaft 6. This further prevents foreign matter from flowing into upper water tank 42, and further prevents wear of main bearing 30 due to foreign matter.

[0072] According to the embodiment described above, it is possible to suppress wear of the main bearing due to foreign matter contained in river water while suppressing an increase in manufacturing costs.

[0073] Although several embodiments of the present invention have been described above, these embodiments are presented as examples and are not intended to limit the scope of the invention. These novel embodiments can be embodied in various other forms, and various omissions, substitutions, and modifications can be made without departing from the spirit of the invention. These embodiments and their modifications are included within the scope and spirit of the invention, and are also included in the inventions and their equivalents as set forth in the claims. [Explanation of symbols]

[0074] 1: vertical shaft Francis turbine, 5: runner, 6: main shaft, 20: bearing device, 30: main bearing, 40: bearing water tank, 41d: axial partition plate, 42: upper water tank, 43: lower water tank, 44: foreign matter collection section, 44a: discharge section, 44b: discharge device, 44c: filter, 44d: inlet section, 45: impeller, 50: main shaft water seal section, 60: foreign matter dropping member, 70: foreign matter inflow prevention member, W: river water

Claims

1. A bearing device for a hydraulic machine used in a hydraulic machine having a runner that is rotationally driven by inflowing river water and a main shaft that rotates in conjunction with the rotation of the runner, a main bearing provided on an outer periphery of the main shaft and supporting the main shaft; an upper water tank that contains the main bearing and lubricating water that immerses the main bearing; a lower water tank provided closer to the runner than the upper water tank and into which a portion of the river water that rotates the runner flows; a main shaft water seal portion that is provided at a position between the lower water tank and the runner, that forms a gap between the main shaft and an outer periphery thereof, through which the river water flows, thereby reducing the flow rate of the river water flowing into the lower water tank; an impeller housed in the lower water tank and rotating together with the main shaft; the lower water tank separates foreign matter from the river water that has flowed in through the gap of the main shaft water seal portion by a swirling component of the river water that is generated due to rotation of the main shaft, the upper water tank stores, as the lubricating water, the river water from which the foreign matter has been separated in the lower water tank; The lower water tank separates the foreign matter from the river water by centrifugal force generated by the rotation of the impeller.

2. A bearing device for a hydraulic machine used in a hydraulic machine having a runner that is rotationally driven by inflowing river water and a main shaft that rotates in conjunction with the rotation of the runner, a main bearing provided on an outer periphery of the main shaft and supporting the main shaft; an upper water tank that contains the main bearing and lubricating water that immerses the main bearing; a lower water tank provided closer to the runner than the upper water tank and into which a portion of the river water that rotates the runner flows; a main shaft water sealing unit that is provided at a position between the lower water tank and the runner, that forms a gap between the main shaft and an outer periphery thereof, through which the river water flows, and that reduces the flow rate of the river water flowing into the lower water tank, the lower water tank separates foreign matter from the river water that has flowed in through the gap of the main shaft water seal portion by a swirling component of the river water that is generated due to rotation of the main shaft, the upper water tank stores, as the lubricating water, the river water from which the foreign matter has been separated in the lower water tank; A bearing device for a hydraulic machine, wherein the lower water tank has a foreign matter collection section provided at a radially outer position to collect the foreign matter contained in the river water.

3. 3. The bearing device for a hydraulic machine according to claim 2, wherein the lower water tank has a discharge section that discharges the foreign matter collected in the foreign matter collection section to the outside together with the river water.

4. a filter that captures the foreign matter discharged from the discharge portion, 4. The bearing device for a hydraulic machine according to claim 3, wherein the lower water tank has an inlet portion through which the river water discharged from the outlet portion and passed through the filter flows back into the lower water tank.

5. 4. The bearing device for a hydraulic machine according to claim 3, further comprising a discharge device that discharges the foreign matter and the river water from the discharge portion at predetermined intervals.

6. a bearing water tank including the upper water tank and the lower water tank, The bearing water tank has a partition plate that divides the interior thereof in the axial direction into the upper water tank and the lower water tank, 2. The bearing device for a hydraulic machine according to claim 1, wherein the lower water tank has a foreign matter recovery section provided at a radially outer position to recover the foreign matter contained in the river water.

7. 7. The bearing device for a hydraulic machine according to claim 6, further comprising a foreign object dropping member provided above the foreign object collecting section, protruding from the partition plate, and dropping the foreign objects toward the foreign object collecting section.

8. 7. A bearing device for a hydraulic machine according to claim 6, further comprising a foreign matter inflow prevention member that is provided at a position closer to the main shaft than the foreign matter collection section, protrudes from the partition plate, and prevents the foreign matter from flowing into the upper water tank.

9. a runner that is rotationally driven by inflowing river water; a main shaft that rotates in accordance with the rotation of the runner; A hydraulic machine comprising: the bearing device for a hydraulic machine according to claim 1 or 2.

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