JP6603382B2 - Vertical shaft pump - Google Patents

Description

  The present invention relates to a vertical shaft pump having a slide bearing, and more particularly to a vertical shaft pump that performs an atmospheric operation and a drainage (water flow) operation such as a prior standby operation pump and a pump that performs a management operation under dry conditions.

  In recent years, due to the progress of urbanization, heat island phenomenon has occurred due to the decrease in green space and the expansion of concrete and asphalt on the road surface, and so-called guerrilla heavy rains frequently occur in urban areas. . A large amount of local rainfall is introduced into the waterway without being absorbed into the ground on concrete and asphalt road surfaces. As a result, a large amount of rainwater flows into the drainage station in a short time.

  In order to prepare for the rapid drainage of a large amount of rainwater caused by such frequent torrential rains, drainage pumps installed in the drainage pump station will prevent rainwater from reaching the drainage pump station to prevent inundation damage due to delays in starting. A pre-standby operation that is started in advance is performed.

  FIG. 1 is a partial schematic diagram of a vertical shaft pump that performs a prior standby operation. The water tank 100 of the drainage station is provided with an impeller 22 at the end of a shaft arranged in the vertical direction, and the impeller 22 is inhaled with air to operate even if the water level of the water tank 100 is below the minimum operating water level LWL. A vertical shaft pump 3 capable of continuing (preceding standby operation) is disposed. This vertical shaft pump 3 is provided with a through hole 5 in the side surface portion of the suction bell 27 on the inlet side of the impeller 22, and an air pipe 6 having an opening 6 a in contact with outside air is attached to the through hole 5. Yes. Thereby, in this vertical shaft pump 3, the supply amount of the air supplied into the vertical shaft pump 3 through the through hole 5 is changed according to the water level, and the drainage amount of the vertical pump 3 is controlled below the minimum operating water level LWL.

  FIG. 2 is a diagram for explaining the operating state of the preceding standby operation. For example, for large city rainwater drainage, a vertical shaft pump is started in advance based on rainfall information or the like regardless of the suction water level (A: air operation). As the water level rises from the low water level, the water level reaches the impeller position, and the vertical shaft pump operates from the idle operation (air operation) to the water agitating with the impeller (B: air / water agitation operation), and from the through hole. It shifts to a full operation (D: steady operation) in which 100% water is discharged through an operation of gradually increasing the amount of water (C: air-water mixing operation) while sucking in the supplied air together with water. When the water level drops from the high water level, the operation shifts from the full operation to the operation (C: air-water mixing operation) in which the amount of water is gradually reduced while the air supplied from the through hole is sucked together with the water. When the water level reaches near LLWL, the operation shifts to an operation (E: air lock operation) in which water is not sucked and drained. These five characteristic operations are collectively referred to as advance standby operation. The pump start is started from the water level LLLWL lower than the lower end of the casing.

  FIG. 3 is a cross-sectional view showing the entire vertical shaft pump 3 that performs the preceding standby operation shown in FIG. The through hole 5 and the air pipe 6 shown in FIG. 2 are not shown. As shown in FIG. 3, the vertical shaft pump 3 is connected to the discharge elbow 30 that is installed and fixed on the pump installation floor, the casing 29 that is connected to the lower end of the discharge elbow 30, and the lower end of the casing 29. A discharge bowl 28 stored inside, and a suction bell 27 connected to the lower end of the discharge bowl 28 for sucking water are provided.

Rotating shafts 10, 10 ′ connected to each other by a shaft coupling 26 are arranged at substantially radial center portions of the casing 29, the discharge bowl 28, and the suction bell 27 of the vertical shaft pump 3.
The rotary shafts 10 and 10 'are supported by an upper bearing 32 fixed to the casing 29 via a support member and a lower bearing 33 fixed to the discharge bowl 28 via a support member. An impeller 22 for sucking water into the pump is connected to one end side (suction bell 27 side) of the rotary shafts 10 and 10 '. The other end side of the rotary shafts 10 and 10 ′ is connected to a driving machine such as an engine or a motor (not shown) that rotates the impeller 22 through the hole provided in the discharge elbow 30 to the outside of the vertical shaft pump 3.

  A shaft seal 34 such as a floating seal, a gland packing, or a mechanical seal is provided between the rotary shafts 10 and 10 'and a hole provided in the discharge elbow 30, and thereby water handled by the vertical pump 3 is supplied to the vertical pump. 3 is prevented from flowing out.

  The driving machine is installed on land so that maintenance and inspection can be easily performed. The rotation of the driving machine is transmitted to the rotating shafts 10, 10 ', and the impeller 22 can be rotated. The water is sucked from the suction bell 27 by the rotation of the impeller 22, passes through the discharge bowl 28 and the casing 29, and is discharged from the discharge elbow 30.

  4 is an enlarged view of a conventional bearing device applied to the bearings 32 and 33 shown in FIG. 3, and FIG. 5 is a perspective view of the slide bearing. As shown in FIG. 4, the conventional bearing device has a metal sleeve 11 made of stainless steel or the like on the outer periphery of the rotary shaft 10 (10 ′). On the outer peripheral side of the sleeve 11, a slide bearing 1 shown in FIG. 5 made of a hollow cylindrical resin material, ceramics, sintered metal, or surface-modified metal is provided. The outer peripheral surface of the sleeve 11 faces the inner peripheral surface (slide surface) of the slide bearing 1 through a very narrow clearance, and is configured to slide with respect to the slide bearing 1. The slide bearing 1 is fixed to a support member 13 connected to a pump casing 29 (see FIG. 3) or the like via a collar portion 12a by a bearing case 12 made of metal or resin.

  The vertical shaft pump 3 shown in FIG. 3 is operated in the atmosphere when the pump is activated. That is, the bearings 32 and 33 are operated under dry conditions without lubrication with liquid. Here, the dry condition refers to a condition in which the atmosphere of the bearings 32 and 33 during the pump operation is in the air without lubrication by the liquid, and the dry operation refers to operation under that condition. Further, the bearings 32 and 33 shown in FIG. 3 are also operated under drainage conditions in which water has passed through the bearings. Here, the drainage condition refers to a condition in which the atmosphere of the bearings 32 and 33 during operation of the pump is in water mixed with foreign matter (slurry) such as earth and sand. It refers to water-mixing operation, full-volume operation, air lock operation, etc. Since the bearings 32 and 33 are used under such conditions, the bearings 32 and 33 have the following problems.

  Various materials are used for the slide bearing 1. In the case of the vertical shaft pump 3 that performs dry operation, a resin or ceramic bearing is used from the viewpoint of dry sliding performance and reliability during drainage operation. There are many. In this case, the slide bearing 1 is required to withstand frictional heat generation during the dry operation and to be resistant to abrasion due to the slurry in the water during the drain operation. However, these two characteristics often contradict each other, and bearing materials with high wear resistance generally tend to have a high friction coefficient. For this reason, if bearing materials are selected giving priority to wear resistance during drainage operation, frictional heat generation under dry conditions will increase, and if bearing materials with a low friction coefficient are selected to suppress frictional heat generation under dry conditions, The wear amount of the bearing material due to the slurry during operation increases.

  In addition, when a polymer material such as resin or rubber is used for the cushioning material disposed between the sliding bearing 1 or the sliding bearing 1 and the bearing case 12, there is an upper limit of the usable temperature determined for each material. The heat generation limit due to friction is determined by the properties of these materials.

In the sliding bearing 1 having the characteristics described above, if the wear resistance of the sliding bearing 1 is improved in order to improve the maintenance and management of the sliding bearing 1, the friction coefficient of the bearing sliding surface increases. The friction described below may occur due to the friction of the bearing sliding surface.

  In general, when a rotary machine such as the vertical shaft pump 3 is operated, the rotary machine may vibrate due to an unbalanced weight of the rotary body itself or an excitation force that is forced on the rotary body due to a fluid load. However, in addition to this, as a cause of vibration of the rotating machine, there is a force generated in a direction (circumferential direction of the rotating body) perpendicular to the displacement direction (radial direction of the rotating body) due to the swing of the rotating body. This force is called destabilizing force and has the function of canceling the damping action of the rotating body. As a result, if the damping action of the entire rotating body becomes negative due to the destabilizing force, divergent vibration (vibration that gradually increases the swinging) may be caused.

  Here, in the aerial operation such as when the vertical shaft pump 3 is activated, since there is no lubricating fluid in the bearing portion as compared with the underwater operation, the bearing sliding surface has a large friction coefficient. Since this frictional force becomes the above destabilizing force, when a bearing material having a high friction coefficient is used, the destabilizing force becomes large and the rotating shafts 10 and 10 'are divergently swung in the direction opposite to the rotational direction. Will cause excessive vibration. Further, when such divergent vibration occurs during dry operation, the bearing surface pressure increases due to the vibration, and the frictional force generated on the bearing sliding surface becomes extremely large. Therefore, there is a possibility that the bearing will malfunction due to thermal expansion or seizure due to a sudden rise in bearing temperature.

  On the other hand, a liquid film is formed on the sliding surface of the sliding bearing 1 during the drainage operation of the vertical shaft pump 3. This liquid film generates a destabilizing force, which may cause a large vibration. This phenomenon occurs in a mechanism similar to a phenomenon called oil whip or oil whirl in a sliding bearing lubricated with oil. When this phenomenon occurs, the rotary shafts 10 and 10 'vibrate violently and normal operation is impossible.

  In order to prevent these vibrations, it is necessary to reduce the destabilizing force or improve the stability of the rotary shafts 10 and 10 'by adding damping. However, as described above, it is difficult to greatly reduce the coefficient of friction that is the cause of the destabilizing force during the dry operation, and due to the structure of the vertical shaft pump 3, a sufficient damping action is given to the rotary shafts 10 and 10 '. It is difficult.

  As described above, a slide bearing for a vertical shaft pump that performs a preliminary standby operation requires performances such as wear resistance, heat generation resistance (low friction property), and vibration resistance. These requirements are simultaneously satisfied at a high level. It has been difficult so far. Also, bearing materials with high wear resistance often cannot be used due to their high friction coefficient under dry conditions, resulting in a problem that the bearing life cannot be greatly improved.

  Further, the vertical shaft pump 3 requires more bearings depending on the length of the rotary shafts 10 and 10 '. In this case, since all the bearings are affected by the occurrence of the vibration and wear progresses, it is necessary to replace all the bearings with a short maintenance span.

  The present invention has been made in view of the above-described conventional problems, and one of the purposes thereof is friction force and liquid film even during dry operation or drainage operation including slurry without sacrificing wear resistance. This is to reduce vibration due to destabilizing force.

  Another object is to reduce the frictional force applied to the bearing sliding surface.

Yet another object is to provide an effective means for reducing the overall wear of all the sliding bearings provided in the vertical shaft pump and extending the overall life.

  In order to achieve the above object, a vertical shaft pump according to an embodiment of the present invention has a first sliding portion on an outer peripheral surface and a second sliding portion on an inner peripheral surface, and is in water and in the atmosphere. A rotatable rotating member; a first sliding bearing that supports the first sliding portion on an inner circumferential surface; and a second sliding bearing that supports the second sliding portion on an outer circumferential surface. .

  In the vertical pump according to another aspect of the present invention, the first sliding bearing is configured to be able to support the first sliding portion in a dry condition and a drainage condition, and the second sliding bearing has a dry condition and It is configured to be able to support the second sliding portion under drainage conditions.

  In the vertical pump according to another aspect of the present invention, the dimension of the diameter gap between the first sliding portion and the first slide bearing is 1/1000 or more of the inner diameter of the first slide bearing, and 1/100. The dimension of the diameter gap between the second sliding portion and the second sliding bearing is 1/1000 or more and 1/100 or less of the outer diameter of the second sliding bearing.

  The dimension of the diameter gap between the first sliding part and the first sliding bearing refers to the difference between the inner diameter of the first sliding bearing and the outer diameter of the first sliding part. The dimension of the diameter gap between the second sliding portion and the second sliding bearing refers to the difference between the inner diameter of the second sliding portion and the outer diameter of the second sliding bearing.

  In the vertical pump according to another aspect of the present invention, the diameter of the second sliding portion and the second sliding bearing with respect to the size of the diameter gap between the first sliding portion and the first sliding bearing. The size ratio of the gap is 0.5 or more and 2.0 or less.

  In the vertical pump according to another aspect of the present invention, the diameter of the second sliding portion and the second sliding bearing with respect to the size of the diameter gap between the first sliding portion and the first sliding bearing. The ratio of the dimension of the gap is 0.7 or more and 1.3 or less.

  In the vertical shaft pump according to another aspect of the present invention, the ratio of the outer diameter of the second sliding bearing to the inner diameter of the first sliding bearing is 0.2 or more and 2.0 or less.

  In the vertical pump according to another aspect of the present invention, the portion of the rotating member located in the water is supported only by the slide bearing.

  In the vertical shaft pump according to another aspect of the present invention, the sliding bearing is PA, PBI, POM, PBT, PET, PPE, PC, UHMW-PE, PTFE, PPS, PI, PEEK, PAR, PSF, PEI, PAI. , PES, and resin material including at least one of PF, ceramics, or metal.

  In the vertical shaft pump according to another aspect of the present invention, the plain bearing includes a resin material to which at least one of carbon fiber, glass fiber, carbon particle, glass particle, and graphite is added.

  In the vertical pump according to another aspect of the present invention, water is supplied to the gap between the first sliding portion and the first slide bearing and the gap between the second sliding portion and the second slide bearing. A flow path through which the gas passes is formed.

  The vertical shaft pump according to another aspect of the present invention is configured to be installed in a drainage station.

  The vertical shaft pump which concerns on another form of this invention equips the water supply port which lets water flow through the said flow path with a strainer.

  A vertical shaft pump according to another aspect of the present invention includes a bearing case that holds the sliding bearing, the bearing case holding the first sliding bearing on an inner circumferential surface thereof, and the second sliding shaft on an outer circumferential surface thereof. Hold the slide bearing.

  In the vertical shaft pump according to another aspect of the present invention, the rotating member is a rotating shaft, and the second sliding portion is provided at an end of the rotating shaft.

  In a vertical shaft pump according to another aspect of the present invention, the first slide bearing and / or the second slide bearing are divided in the circumferential direction.

  The vertical shaft pump according to another aspect of the present invention is a vertical shaft pump including a plurality of bearing devices, wherein at least one of the bearing devices includes the first slide bearing and the second slide bearing.

  According to the present invention, it is possible to reduce vibration due to frictional force, destabilizing force due to a liquid film, and the like during dry operation or drainage operation including slurry without sacrificing wear resistance. In addition, according to the present invention, the frictional force applied to the bearing sliding surface can be reduced, and as a result, the amount of heat generated by the sliding bearing can be reduced, so that a bearing material with a higher friction coefficient, that is, a bearing with higher wear resistance. Material can be used.

  Further, the vertical shaft pump provided with a plurality of slide bearings has a configuration in which at least one set of the slide bearings is a combination of the first slide bearing and the second slide bearing, whereby the slide provided for the vertical pump is provided. It is possible to provide an effective means for reducing overall bearing wear and extending overall life.

It is a partial schematic diagram of a vertical shaft pump that performs a preliminary standby operation. It is a figure explaining the driving | running state of a prior | preceding standby driving | operation. It is sectional drawing which shows the whole vertical shaft pump which performs a prior | preceding standby operation. It is an enlarged view of the conventional bearing device. It is a perspective view of a slide bearing. It is a longitudinal cross-sectional view of the bearing apparatus applied to the vertical shaft pump which concerns on this embodiment. It is sectional drawing in the XX 'cross section shown in FIG. It is a figure which shows operation | movement of the bearing apparatus at the time of dry operation. It is a figure which shows operation | movement of the bearing apparatus at the time of drainage operation. It is a figure which shows the vibration speed when the vertical shaft pump which concerns on this embodiment performs dry operation. It is a figure which shows the bearing temperature when the vertical shaft pump which concerns on this embodiment performs dry operation. It is a figure which shows the vibration speed when the vertical shaft pump which concerns on this embodiment performs drainage operation. It is a longitudinal cross-sectional view of the bearing apparatus applied to the vertical shaft pump which concerns on other embodiment. It is a longitudinal cross-sectional view of the bearing apparatus applied to the vertical shaft pump which concerns on other embodiment. It is a longitudinal cross-sectional view of the bearing apparatus applied to the vertical shaft pump which concerns on other embodiment. It is a longitudinal cross-sectional view of the bearing apparatus applied to the vertical shaft pump which concerns on other embodiment. It is a longitudinal cross-sectional view of the bearing apparatus applied to the vertical shaft pump which concerns on other embodiment. It is sectional drawing in the XX 'cross section shown in FIG. It is a longitudinal cross-sectional view of the bearing apparatus applied to the vertical shaft pump which concerns on other embodiment. It is a cross-sectional view of the bearing device applied to the vertical shaft pump according to another embodiment. It is a cross-sectional view of the bearing device applied to the vertical shaft pump according to another embodiment. It is a schematic sectional drawing of the vertical shaft pump which concerns on other embodiment. It is a cross-sectional view of a bearing device used as a bottom bearing. It is a cross-sectional view of another bearing device used as a bottom bearing.

  Embodiments of the present invention will be described below with reference to the drawings. 6 to 24, the same or corresponding components are denoted by the same reference numerals, and redundant description is omitted.

  FIG. 6 is a longitudinal sectional view of a bearing device applied to the vertical shaft pump according to the present embodiment. The vertical pump according to the present embodiment applies the bearing device shown in FIG. 6 instead of the bearings 32 and 33 of the vertical pump 3 that performs the preliminary standby operation shown in FIG. Since the configuration is the same as that of the vertical pump 3 shown in FIG. 3, the description of the entire vertical pump 3 according to this embodiment is omitted.

  This bearing device has a metal sleeve 11 made of cemented carbide or stainless steel on the outer periphery of the rotary shaft 10 (10 '). On the outer peripheral side of the sleeve 11, there is provided a first plain bearing 1 made of a hollow cylindrical resin material, ceramics, sintered metal or surface-modified metal shown in FIG. 5. The outer peripheral surface (first sliding portion 17) of the sleeve 11 faces the inner peripheral surface (sliding surface) of the first slide bearing 1 via a very narrow first clearance 7, and the first slide bearing. It is configured to slide against one sliding surface. The outer peripheral portion of the first plain bearing 1 is fixed to the inner peripheral surface of a bearing case 12 made of metal or resin, and the bearing case 12 is connected to the casing 29 (see FIG. 3) of the vertical shaft pump 3 via a collar portion 12a. ) And the like are fixed to the supporting member 13 by fixing means 21b such as bolts.

  Further, on the outer peripheral surface of the first bearing case 12, a second sliding bearing 9 made of a hollow cylindrical resin material, ceramics, sintered metal, or surface-modified metal is provided. A sleeve case 15 is fixed to the rotating shaft 10 (10 ') by fixing means 21a such as a fixing pin or a bolt. The sleeve case 15 is configured to rotate in the same manner as the rotation shaft 10 (10 ′) when the rotation shaft 10 (10 ′) rotates. A sleeve 14 is provided on the inner peripheral surface of the sleeve case 15. The inner peripheral surface (second sliding portion 18) of the sleeve 14 faces the outer peripheral surface (sliding surface) of the second slide bearing 9 via a very narrow second clearance 8, and the second slide bearing 9 It is comprised so that it may slide with respect to the sliding surface.

  The sleeve case 15 is provided with a water supply port 19 through which water containing slurry or the like passes through the first clearance 7 and the second clearance 8. The water that has flowed into the water supply port 19 passes through the first clearance 7 and the second clearance 8 as flow paths. In this way, a flow path for allowing water to pass through the first clearance 7 and the second clearance 8 is formed, and the first clearance 7 and the second clearance 8 also function as a flow path. Water can flow promptly through the first clearance 7 and the second clearance 8 without staying, and the functions of the first slide bearing 1 and the second slide bearing 9 can be exhibited quickly.

  The first slide bearing 1 and the second slide bearing 9 support the sleeve 11 and the sleeve 14 under dry conditions when the vertical shaft pump 3 is started, and the sleeve 11 and sleeve through a very thin liquid film under drainage conditions. 14 is supported.

  The diameter of the first clearance 7 is used to suppress the steady swing of the rotary shaft 10 (10 ') and to suppress the load applied to the first slide bearing 1 and the second slide bearing 9 due to the swing. The clearance dimension (the inner diameter of the first sliding bearing 1−the outer diameter of the sleeve 11) and the diameter clearance dimension of the second clearance 8 (the inner diameter of the sleeve 14−the outer diameter of the second sliding bearing 9) are respectively the first. It is preferable that it is 1/1000 or more and 1/100 or less of the inner diameter of the slide bearing 1 and 1/1000 or more and 1/100 or less of the outer diameter of the second slide bearing 9. When the dimensions of the first clearance 7 and the second clearance 8 are larger than these ranges, the steady swing of the rotary shaft 10 (10 ′) becomes large, and the swing of the first slide bearing 1 and the second clearance 8 increases. The load applied to the second plain bearing 9 also increases, and stable operation may be difficult. Further, when the dimensions of the first clearance 7 and the second clearance 8 are smaller than these ranges, the first clearance 7 and the second clearance 8 are blocked by foreign matter, or the first slide bearing 1 and the second clearance 8 are closed. 2 may be seized due to friction with foreign matter.

  The diameter clearance dimension of the first clearance 7 and the diameter clearance dimension of the second clearance 8 are preferably the same, but the first sliding bearing 1, the second sliding bearing 9, the sleeve 14, or the sleeve 11 is made of resin. If these members have elasticity, such as being formed of, the function of the present invention is exhibited even if there is a difference in dimensions. In this case, the ratio of the diameter clearance dimension of the second clearance 8 to the diameter clearance dimension of the first clearance 7 is preferably 0.5 or more and 2.0 or less, more preferably 0.7 or more and 1.3. It is as follows. However, as will be described later, when the first slide bearing 1, the second slide bearing 9, the sleeve 14, or the sleeve 11 is further fixed via a cushioning material such as rubber (see FIG. 13), the cushioning is performed. The first slide bearing 1 and the second slide bearing 9 can be in contact with the sleeve 11 and the sleeve 14 at the same time, even if they are not in the above-mentioned range due to the deformation of the material, and the function of the present invention is exhibited.

  FIG. 7 is a cross-sectional view taken along the line XX ′ shown in FIG. As shown in the drawing, the centers of the outer peripheral surface of the sleeve 11, the inner peripheral surface of the first slide bearing 1, the outer peripheral surface of the second slide bearing 9, and the inner peripheral surface of the sleeve 14 are substantially coincident with the central axis O. Is configured to do. In FIG. 7, the dimensions of the first clearance 7 and the second clearance 9 are shown enlarged for convenience.

FIG. 8 is a diagram illustrating the operation of the bearing device during the dry operation. When the rotating shaft 10 (10 ′) rotates, the sleeve 11 fixed to the rotating shaft 10 (10 ′) and the sleeve 14 fixed to the sleeve case 15 also rotate. Under dry conditions, when the outer peripheral surface of the sleeve 11 contacts the first slide bearing 1 at point A, a bearing reaction force _FAN is generated on the rotary shaft 10 (10 ′). This bearing reaction force _{F AN,} frictional force _{F AF} is generated in a direction opposite to the rotating direction of the rotary shaft 10 (10 '), opposite the friction force _{F AF} is the rotational direction in the rotation shaft 10 (10') It becomes a destabilizing force that causes a whirling vibration in the direction.

On the other hand, when the sleeve 14 contacts the second sliding bearing 9 at the point B, a bearing reaction force _FBN is generated, and this bearing reaction force _FBN is a force in a direction opposite to the frictional force _FAF. A frictional force _FBF is generated. For the system of the rotating shaft 10 (10 ′), the frictional force _FAF and the frictional force _FBF cancel each other, so that the rotating shaft 10 (10 ′) can rotate stably. Further, since the load (bearing reaction force) relating to the rotating shaft 10 (10 ') is dispersed at the points A and B, the frictional force applied to the slide bearing is also dispersed. As a result, heat generation due to friction is reduced, and the temperature rise of the bearing during dry operation is suppressed.

FIG. 9 is a diagram illustrating the operation of the bearing device during the drain operation. The first clearance 7 and the second clearance 8 are filled with water, and this water constitutes a liquid film 41 and a liquid film 42, respectively, and this bearing device functions as a fluid lubrication bearing device. At this time, a pressure non-uniformity in the circumferential direction is generated in the liquid film 41 due to the rotation of the rotating shaft 10 (10 ′).
0') radial fluid forces _{F AR} and the circumferential fluid force _{F AT} occurs. The circumferential fluid force F _AT becomes destabilizing force that generates vibrations during drainage operation. Incidentally, the circumferential fluid force F _AT is the frictional force F _AF generated by the drying operation is a reverse force.

  Conventionally, in order to prevent unstable vibration due to the liquid film in the vertical rotating shaft, the inner surface of the bearing is formed in a multi-arc shape instead of a perfect circle shape. However, when a bearing made of a resin is used in water containing a large amount of slurry, the inner surface shape of the bearing approaches a perfect circle shape due to wear, and the vibration suppressing effect may be lost.

Here, according to this bearing device, in the liquid film 42 in the second clearance 8, circumferential pressure non-uniformity occurs due to the rotation of the sleeve 14, and as a result, the radial fluid force F is applied to the rotating shaft 10 (10 ′). _BR and circumferential fluid force _FBT are generated. At this time, the circumferential fluid force F _AT and the circumferential fluid force F _BT is opposite to each other, the liquid film 41, destabilizing forces due to the liquid film 42 is canceled, the rotary shaft 10 (10 ') is not It can rotate stably without generating vibration due to the stabilizing force.

  FIG. 10 is a diagram illustrating a vibration speed when the vertical shaft pump 3 according to the present embodiment including the bearing device illustrated in FIG. 6 is in a dry operation. For comparison with the vertical shaft pump 3, the vibration speed when the vertical shaft pump (conventional structure) including the conventional bearing device shown in FIG. Note that both the conventional bearing device and the bearing device shown in FIG. 6 use the same material having high wear resistance and a high friction coefficient as a slide bearing. As shown in the figure, it can be seen that the vertical shaft pump 3 (this embodiment) provided with the bearing device is operated at a lower vibration speed than the conventional structure in a constant manner from the start to the stop.

  FIG. 11 is a diagram showing the bearing temperature when the vertical shaft pump 3 according to the present embodiment including the bearing device shown in FIG. 6 is dry operated. For comparison with the vertical shaft pump 3, the bearing temperature when the vertical shaft pump (conventional structure) including the conventional bearing device shown in FIG. Note that both the conventional bearing device and the bearing device shown in FIG. 6 use the same material having high wear resistance and a high friction coefficient as a slide bearing. As shown in the figure, in the vertical shaft pump 3 (this embodiment) provided with the present bearing device, it can be seen that the bearing temperature is kept constant from the start to the stop as compared with the conventional structure.

  As shown in FIGS. 10 and 11, in the vertical shaft pump having the conventional bearing device, the frictional force applied to the rotating shaft is large, so that a large vibration is generated, and as a result, the temperature rise of the bearing is increased. . On the other hand, in the vertical shaft pump 3 provided with the present bearing device, as described with reference to FIG. 8, it is possible to reduce vibrations and frictional forces, and to suppress an increase in bearing temperature.

  FIG. 12 is a diagram illustrating a vibration speed when the vertical shaft pump 3 according to the present embodiment including the bearing device illustrated in FIG. 6 performs a drain operation. For comparison with the vertical shaft pump 3, the vibration speed when the vertical pump (conventional structure) including the conventional bearing device shown in FIG. In addition, the result shown in FIG. 12 measured the vibration at the time of driving | running on the conditions which a vibration tends to generate | occur | produce as a driving | running condition of a vertical shaft pump. As shown in the figure, it can be seen that the vertical shaft pump 3 (this embodiment) provided with the bearing device is operated at a lower vibration speed than the conventional structure in a constant manner from the start to the stop.

As described above, according to the vertical shaft pump 3 according to the present embodiment, the first slide bearing 1 and the second slide bearing 9 are caused by the swing of the shaft of the rotary shaft 10 (10 ′) during the dry operation. Even if the rotating bodies (sleeve 11 and sleeve 14) collide with each other, the directions of the frictional forces act in opposite directions to cancel each other at the time of the collision, thereby suppressing the divergence of the rotation of the rotating shaft 10 (10 '). Vibration due to destabilization can be prevented. In addition, it is possible to reduce friction caused by this vibration and suppress an increase in bearing temperature.

  Since the vertical shaft pump 3 according to the present embodiment includes the first slide bearing 1 and the second slide bearing 9, the frictional force of the bearing slide surface during the dry operation is dispersed to suppress heat generation due to the friction of the bearing slide surface. can do. Thereby, a bearing material having a higher friction coefficient than that of the conventional structure, that is, a bearing material having higher wear resistance can be used, and stable operation can be performed for a long period of time.

  In the vertical pump 3 according to the present embodiment, the first slide bearing 1 is held on the inner peripheral surface of the bearing case 12 and the second slide bearing 9 is held on the outer peripheral surface thereof. The structure can be made compact in the direction.

  In the vertical shaft pump 3, the portions (the sleeve 11 and the sleeve 14) located in the water of the rotary shaft 10 (10 ′) are supported only by the sliding bearings such as the first sliding bearing 1 and the second sliding bearing 9. Is called. That is, a rolling bearing such as a ball bearing or a roller bearing is not suitable for a rotary machine that performs drainage operation such as the vertical shaft pump 3, and the effect of the present embodiment can be achieved by a sliding bearing.

  Next, a vertical shaft pump according to another embodiment will be described. FIG. 13 is a longitudinal sectional view of a bearing device applied to a vertical shaft pump according to another embodiment. As shown in the drawing, in this bearing device, a cushioning material 20a such as rubber and a cushioning material 20b are disposed on the back side (outer peripheral side) of the first slide bearing 1 and on the rear side (outer peripheral side) of the sleeve 14.

  By providing the cushioning material 20a and the cushioning material 20b, even if a material that is vulnerable to impact, such as silicon nitride or silicon carbide, is used for the first slide bearing 1 and the sleeve 14, damage due to impact during operation can be prevented. it can. In addition, as described above, even if the dimensions of the first clearance 7 and the second clearance 8 are not in the above-described range, the cushioning material 20a and / or the cushioning material 20b are deformed, so that the first sliding bearing 1 and The second sliding bearing 9 can simultaneously contact the sleeve 11 and the sleeve 14 at the same time, and the above-described destabilizing force canceling effect can be sufficiently obtained.

  In addition, although the shock absorbing material 20a and the shock absorbing material 20b are arrange | positioned at the back side of the 1st slide bearing 1 and the back side of the sleeve 14, an arrangement place is not restricted to this. For example, the back side (inner peripheral side) of the sleeve 11 and the back side (inner peripheral side) of the second slide bearing 9, the back side of the sleeve 11 and the back side of the sleeve 14, or the back side of the first slide bearing 1. And the buffer material 20a and the buffer material 20b can be provided in the back surface side of the 2nd slide bearing 9. FIG.

  FIG. 14 is a longitudinal sectional view of a bearing device applied to a vertical shaft pump according to another embodiment. As shown in the figure, in this bearing device, a metal back metal 31a is arranged on the back side (outer peripheral side) of the first sliding bearing 1 made of a resin material, and on the back side (outer peripheral side) of the back metal 31a. A buffer material 20a is arranged. Similarly, a metal back metal 31b is disposed on the back side (outer peripheral side) of the sleeve 14, and a cushioning material 20b is disposed on the back side (outer peripheral side) of the back metal 31b. Even with such a complicated structure, the same effect as the bearing device shown in FIG. 6 can be obtained.

The back metal 31a and the back metal 31b are arranged on the back side of the first plain bearing 1 and the back side of the sleeve 14, but the arrangement location is not limited to this. For example, the back side of the sleeve 11 and the back side of the second slide bearing 9, the back side of the sleeve 11 and the back side of the sleeve 14, or the back side of the first slide bearing 1 and the back side of the second slide bearing 9. Further, the back metal 31a and the back metal 31b can be provided together with the buffer material 20a and the buffer material 20b.

  FIG. 15 is a longitudinal sectional view of a bearing device applied to a vertical shaft pump according to another embodiment. In this bearing device, a metal material such as cemented carbide or stainless steel is used as the material of the second sliding bearing 9, and a resin material is used as the material of the sleeve 14. Thus, even if the materials of the slide bearing and the sleeve are opposite, the same effect as the bearing device shown in FIG. 6 can be obtained.

  FIG. 16 is a longitudinal sectional view of a bearing device applied to a vertical shaft pump according to another embodiment. In this bearing device, the components are arranged so as to be opposite in the axial direction of the rotary shaft 10 (10 ′). Even with such a structure, the same effect as the bearing device shown in FIG. 6 can be obtained.

  FIG. 17 is a longitudinal sectional view of a bearing device applied to a vertical pump according to another embodiment, and FIG. 18 is a sectional view in the XX ′ section shown in FIG. 17. The vertical shaft pump 3 is required to easily perform maintenance such as inspection and replacement of consumable parts while being installed in the drainage station. Further, at the time of assembly, depending on the shape of the vertical shaft pump 3, the sleeve case 15 and the sleeve 14 are fixed to the rotating shaft 10 (10 ') after passing the rotating shaft 10 (10') through the inside of the first slide bearing 1. There is a need to.

  Therefore, in this bearing device, as shown in FIG. 18, the sleeve case 15 and the sleeve 14 are divided into two parts, and the divided sleeve case 15 is coupled to each other by a fixing bolt 24, so 10 (10 ′) can be fixed. By configuring the sleeve case 15 and the sleeve 14 in this way, assembly and disassembly can be easily performed at the installation site of the vertical shaft pump 3.

  FIG. 19 is a longitudinal sectional view of a bearing device applied to a vertical shaft pump according to another embodiment. In the present bearing device, a strainer 23 having an opening (mesh width) smaller than the size of the first clearance 7 and the size of the second clearance 8 is provided in the water supply port 19. As a result, even if a slurry such as earth and sand is mixed in the drainage, a slurry larger than the size of the first clearance 7 and the size of the second clearance 8 enters the first clearance 7 and the second clearance 8. This can be prevented. As a result, the diameter of the slurry contained in the water passing through the first clearance 7 and the second clearance 8 becomes sufficiently small, and wear of the sliding surface of the first sliding bearing 1 and the sliding surface of the second sliding bearing 9 occurs. Can be reduced. That is, the dimension of the first clearance 7 and the dimension of the second clearance 8 can be maintained, and the cancellation of the destabilizing force described in FIGS. 8 and 9 can be performed continuously.

  The opening diameter of the strainer 23 is preferably less than or equal to half the dimensions of the first clearance 7 and the second clearance 8. Moreover, it is preferable that the water supply port 19 is provided in the sleeve case 15 at equal intervals along the circumference centering on the central axis of the rotating shaft 10 (10 ').

FIG. 20 is a cross-sectional view of a bearing device applied to a vertical shaft pump according to another embodiment. In this bearing device, a plurality of grooves 35 a are formed along the axial direction on the inner peripheral surface (slip surface) of the first slide bearing 1 and on the outer peripheral surface (slip surface) of the second slide bearing 9. The difference in curvature between the sleeve 11 and the inner peripheral surface (slide surface) of the first slide bearing 1 and the difference in curvature between the sliding surface of the sleeve 14 and the outer peripheral surface (slide surface) of the second slide bearing 9 are as follows. Since it is extremely small, even if the groove 35a is formed in this way, the influence on the contact state between the first slide bearing 1 and the sleeve 11 and the contact state between the second slide bearing 9 and the sleeve 14 is small. The same effect as the bearing device shown in FIG. Further, by forming the groove 35a in this way, the flow rate of water passing through the first clearance 7 and the second clearance 8 can be increased.

  The groove 35a may be formed only in one of the first slide bearing 1 and the second slide bearing 9. Further, the groove 35a may be provided on the sleeve side. The groove 35a may be formed not only in the axial direction of the rotary shaft 10 (10 ') but also in the circumferential direction, an oblique direction with respect to the axial direction, or one or a plurality of threads.

  FIG. 21 is a cross-sectional view of a bearing device applied to a vertical shaft pump according to another embodiment. In this bearing device, the first slide bearing 1 and the second slide bearing 9 are divided into a plurality of parts in the circumferential direction, and are arranged on the inner peripheral surface of the sleeve case 15 via a gap 35b. Even with such a bearing device, the same effect as the bearing device shown in FIG. 6 can be obtained.

  Only one of the first slide bearing 1 and the second slide bearing 9 may be divided and formed. Further, the gap 35b may be provided on the sleeve side, that is, the sleeve 11 and / or the sleeve 14 may be divided.

  In the bearing device of the vertical shaft pump according to each embodiment described above, the arrangement of the second sliding bearing 9 on the rotating shaft 10 (10 ′) is not limited, and the liquid contact portion on the rotating shaft 10 (10 ′). That is, the effect of the present invention can be obtained regardless of where it is provided within the vertical shaft pump. In addition, the second slide bearing 9 is disposed outside the vertical pump (on the drive side), for example, in a structure that comes into contact with water even when pumping, not in the vertical pump, and the vertical pump is connected during drainage operation by connecting the interior of the vertical pump and piping. If the structure is lubricated by the discharged water, the effects of the present invention are similarly obtained.

  In the vertical shaft pumps according to the embodiments described above, instead of the bearing 32 and the bearing 33 of the vertical shaft pump 3 that performs the preliminary standby operation illustrated in FIG. 3, FIGS. 6, 13, 14, 15, 16, The bearing devices shown in FIGS. 17 and 19 have been described as being applied. However, the present invention is not limited to this, and instead of any one of the bearing 32 and the bearing 33, these bearing devices may be applied. In this case, when the vertical shaft pump 3 includes at least one of these bearing devices, the swing of the rotary shaft 10 (10 ′) can be remarkably reduced. As a result, the vibration applied to all the bearings is reduced, the wear of the bearings is reduced, the life of all the bearings can be extended as a whole, and the maintenance span can be increased.

  Further, in the vertical shaft pump, the number of bearing devices is increased according to the length of the rotary shaft 10 (10 ′), and there may be three or more bearing devices. Even in such a case, as this bearing device, at least one of the bearing devices shown in FIGS. 6, 13, 14, 15, 16, 17, and 19, that is, a member that can rotate together with the rotary shaft 10 (10 ′) is used. By providing at least one set of the first slide bearing 1 capable of sliding contact with the inner peripheral surface and the second slide bearing 9 capable of sliding contact with the outer peripheral surface of the rotatable member together with the rotary shaft 10 (10 ′), The whirling of the rotating shaft 10 (10 ′) can be significantly reduced. As a result, the vibration applied to all the bearings is reduced, the wear of the bearings is reduced, the life of all the bearings can be extended as a whole, and the maintenance span can be increased.

  FIG. 22 is a schematic cross-sectional view of a vertical shaft pump according to another embodiment. As shown in the figure, in the vertical shaft pump 3, the rotary shaft 10 ′ passes through the impeller 22, and a bottom bearing 37 supported by the support member 13 is provided at the tip portion thereof. A bearing cover 38 for adjusting the water flow is provided on the opposite side of the bottom bearing 37 from the rotary shaft 10 ′.

FIG. 23 is a cross-sectional view of a bearing device used as the bottom bearing 37 of the vertical shaft pump 3 shown in FIG. As shown in the figure, in the present bearing device, a sleeve 11 is provided on the outer periphery of the rotating shaft 10 ', and the end of the rotating shaft 10' is formed in a concave shape. A sleeve 14 is provided on the inner periphery of the concave end portion via a cushioning material 20b. The first sliding bearing 1 facing the sleeve 11 via the first clearance 7 is provided with a cushioning material 20a on the back side (outer peripheral side) and fixed to the bearing case 12. A second slide bearing 9 is disposed on the inner peripheral side of the sleeve 14 with a second clearance 8 therebetween, and the inner peripheral surface of the sleeve 14 and the outer peripheral surface of the second slide bearing 9 slide on each other. It is configured to touch. The second plain bearing 9 is fixed by a bearing case 16, and the bearing case 16 is fixed to the support member 13 by a bolt 21c. The bearing case 16 is provided with a water supply port 19, and the water passed through the water supply port 19 passes through the first clearance 7 and the second clearance 8, so that this bearing device is a fluid lubrication bearing device. Function.

  According to this bearing device, the same effect as the bearing device shown in FIG. 6 can be obtained. In addition, by providing the sleeve 14 at the end of the rotating shaft 10 ′, the diameter of the inner peripheral surface (second sliding surface) of the sleeve 14 can be reduced. Thereby, the peripheral speed of the inner peripheral surface of the sleeve 14 can be reduced, and heat generation due to friction of the second slide bearing 9 can be suppressed. Further, since the second slide bearing 9 is arranged near the end of the rotary shaft 10 ', the second slide bearing 9 can be easily attached and replaced, and this bearing device can be used in an existing vertical shaft pump. Can be easily applied. Although not shown, it is preferable to provide a substantially hemispherical bearing cover 38 (see FIG. 22) below the bearing case 16 (water inflow side) so as not to disturb the water flow. In this case, in order to reduce the mixing of the slurry mixed in the water into the first clearance 7 and the second clearance 8, the bearing cover 38 is provided with a water supply port in a direction perpendicular to the water flow direction. Is more preferably configured to be connected to the water supply port 19 of the bearing case 16.

  24 is a cross-sectional view of another bearing device used as the bottom bearing 37 of the vertical shaft pump 3 shown in FIG. In the present bearing device, the end of the rotating shaft 10 'is formed in a concave shape, and a sleeve 14 is provided on the inner periphery of the concave end through a cushioning material 20b. The sleeve 14 is pressed from below by a pressing plate 36 and is fixed to the rotating shaft 10 ′. Further, the sleeve 14 is disposed at substantially the same position in the axial direction with respect to the sleeve 11. Thereby, the installation volume of this bearing apparatus can be made small.

  In the bearing device applied to the vertical shaft pump according to each embodiment described above, the ratio of the outer diameter of the second sliding bearing 9 to the inner diameter of the first sliding bearing 1 is 0.2 or more and 2.0 or less. Preferably there is. If the ratio of the diameter of the outer peripheral surface (slip surface) of the second sliding bearing 9 exceeds this range, the peripheral speed of the sleeve 14 increases, and heat generation due to friction during dry operation increases, which is not preferable. When a plurality of first slide bearings 1 having different inner diameters are used, the second slide bearing has an outer diameter that is not less than 0.2 times the minimum diameter and not more than 2.0 times the maximum diameter. 9 is preferably used.

Moreover, in the bearing device applied to the vertical shaft pump according to each embodiment described above, the material used for the first sliding bearing 1 and the second sliding bearing 9 is a long-term bearing in dry operation and drainage operation. In order to function, a low coefficient of friction during dry operation and high wear resistance in water containing slurry are required. Therefore, the first slide bearing 1 and the second slide bearing 9 are PA (polyamide), PBI (polybenzimidazole), POM (polyacetal), PBT (polybutylene terephthalate), PET (polyethylene terephthalate), PPE (polyphenylene ether), PC (polycarbonate), UHMW-PE (ultra high molecular weight polyethylene), PTFE (polytetrafluoroethylene), PPS (polyphenylene sulfide), PI (polyimide), PEEK (polyether ether ketone), PAR Abrasion resistance comprising a resin material comprising at least one of (polyarylate), PSF (polysulfone), PEI (polyetherimide), PAI (polyamideimide), PES (polyethersulfone), and PF (phenolic resin) High quality It is preferably formed of a fee.

  Further, the first slide bearing 1 and the second slide bearing 9 are reinforced / modified materials containing a material obtained by adding carbon fiber, glass fiber, carbon particle, glass particle, graphite or the like to the resin material. More preferably, it is formed by. Moreover, the 1st slide bearing 1 and the 2nd slide bearing 9 may be formed with the material containing ceramics or metals, such as silicon nitride and silicon carbide, from a viewpoint which needs to be provided with high abrasion resistance.

The specific wear amount of these materials (index of wear resistance defined by friction volume / bearing load / travel distance) is at least 1 × 10 ⁻⁶ mm ² / N or less, depending on the material, 1 × 10 ⁻⁷ mm ² / N or less. For this reason, in the conventional structure, it was necessary to select a material having both low friction and wear resistance. However, since the above material has low friction, only the wear resistance needs to be considered.

  The sleeve 11 and the sleeve 14 can be formed of a metal material such as cemented carbide and stainless steel, ceramics, or a material containing the above resin material, and a material with high wear resistance is preferable. The materials of the first slide bearing 1 and the second slide bearing 9 may be different from each other. The materials of the sleeve 11 and the sleeve 14 may be different from each other. The present invention can reduce the destabilizing force no matter what friction coefficient is used for the first slide bearing 1, the second slide bearing 9, the sleeve 11 and the sleeve 14.

  The present invention is not limited to the vertical pump according to the above-described embodiment, but is a vertical pump having a slide bearing, particularly an air operation, an air / water agitation operation, an air / water mixing operation, a steady operation, and an air lock operation in the preceding standby operation. In addition, it can be suitably used for a vertical shaft pump in which the load applied to the bearing changes in each operating state and the destabilizing force changes.

  Moreover, the vertical shaft pump which concerns on each said embodiment is comprised so that installation in a drainage machine place is possible. Since the drainage station that drains rainwater for sewerage such as a combined type discharges water containing slurry, the vertical shaft pumps according to the above embodiments are suitable for the drainage station. In particular, in a drainage station that is a deep-type rainwater drainage facility and uses a post-sedimentation system in which a sedimentation basin is provided on the discharge side of the pump, a pre-sedimentation system drainage station in which a sedimentation basin is installed before the pump flows in. Since the amount of slurry is large as compared with the above, the vertical shaft pump according to each of the above embodiments can be used more suitably.

  The embodiment described above is described for the purpose of enabling the person having ordinary knowledge in the technical field to which the present invention belongs to implement the present invention. Various modifications of the above embodiment can be naturally made by those skilled in the art, and the technical idea of the present invention can be applied to other embodiments. Accordingly, the present invention is not limited to the described embodiments, but is to be construed in the widest scope according to the technical idea defined by the claims.

DESCRIPTION OF SYMBOLS 1 1st slide bearing, 3 vertical shaft pump, 5 through-hole, 6 air pipe, 6a opening, 7 1st clearance, 8 2nd clearance, 9 2nd slide bearing, 10 rotating shaft, 10 'rotating shaft, DESCRIPTION OF SYMBOLS 11 Sleeve, 12 Bearing case, 12a Collar part, 13 Support member, 14 Sleeve, 15 Sleeve case, 16 Bearing case, 17 1st sliding part, 18
2nd sliding part, 19 Water supply port, 20a Buffer material, 20b Buffer material, 21a Fixing means, 21b Fixing means, 22 Impeller, 23 Strainer, 24 Fixing bolt, 27 Suction bell, 28 Discharge bowl, 29 Casing, 30 Discharge Elbow, 31a Back metal, 31b Back metal, 32 Upper bearing, 33 Lower bearing, 34 Shaft seal, 35a Groove, 35b Clearance, 36 Presser plate, 37 Bottom bearing, 38 Bearing cover, 100
Aquarium.

Claims (20)

A rotation member including at least a rotation shaft, having a first sliding portion and a second sliding portion, and rotatable in water and in the atmosphere;
An impeller attached to the rotating shaft;
A first plain bearing that supports the first sliding portion on an inner peripheral surface;
A second plain bearing for supporting the second sliding portion on the outer peripheral surface,
The rotating shaft extends through the impeller;
The first sliding bearing and the second sliding bearing are vertical shaft pumps provided below the impeller. A rotation member including at least a rotation shaft, having a first sliding portion and a second sliding portion, and rotatable in water and in the atmosphere;
A first plain bearing that supports the first sliding portion on an inner peripheral surface;
A second plain bearing for supporting the second sliding portion on the outer peripheral surface,
A vertical shaft pump having a buffer material on at least one of an outer peripheral side of the first sliding bearing and an inner peripheral side of the second sliding bearing. A rotation member including at least a rotation shaft, having a first sliding portion and a second sliding portion, and rotatable in water and in the atmosphere;
A first plain bearing that supports the first sliding portion on an inner peripheral surface;
A second plain bearing for supporting the second sliding portion on the outer peripheral surface,
The first sliding portion and the second sliding portion both include a sleeve,
A vertical shaft pump having a buffer material on at least one of an inner peripheral surface of the sleeve of the first sliding portion and an outer peripheral surface of the sleeve of the second sliding portion. In the vertical shaft pump according to any one of claims 1 to 3,
The first sliding portion is an outer peripheral surface of a sleeve attached to the rotating shaft, and the second sliding portion is a sleeve attached to the inner peripheral surface of a sleeve case attached to the rotating shaft. A vertical shaft pump having an inner peripheral surface. In the vertical shaft pump according to any one of claims 1 to 3,
The first sliding portion is an outer peripheral surface of a sleeve attached to the rotating shaft, and the second sliding portion is an inner peripheral surface of a sleeve attached to the rotating shaft. Vertical shaft pump. In the vertical shaft pump according to any one of claims 1 to 5,
The vertical shaft pump, wherein the first sliding bearing and the second sliding bearing are configured to support a tip portion of the rotating shaft. The first plain bearing is configured to be able to support the first sliding portion in a dry condition and a drainage condition,
The vertical shaft pump according to any one of claims 1 to 6, wherein the second sliding bearing is configured to be able to support the second sliding portion in a dry condition and a drainage condition. The dimension of the diameter gap between the first sliding portion and the first sliding bearing is 1/1000 or more and 1/100 or less of the inner diameter of the first sliding bearing,
The diameter clearance between the second sliding portion and the second sliding bearing has a dimension that is 1/1000 or more and 1/100 or less of the outer diameter of the second sliding bearing. Vertical shaft pump described in any one of the above.   The ratio of the dimension of the diameter gap between the second sliding part and the second sliding bearing to the dimension of the diameter gap between the first sliding part and the first sliding bearing is 0.5 or more. The vertical shaft pump according to any one of claims 1 to 8, wherein the vertical shaft pump is 0 or less.   The ratio of the dimension of the diameter gap between the second sliding part and the second sliding bearing to the dimension of the diameter gap between the first sliding part and the first sliding bearing is 0.7 or more. The vertical shaft pump according to claim 9, which is 3 or less.   11. The vertical pump according to claim 1, wherein a ratio of an outer diameter of the second sliding bearing to an inner diameter of the first sliding bearing is 0.2 or more and 2.0 or less.   The vertical shaft pump according to any one of claims 1 to 11, wherein a portion of the rotating shaft located in water is supported only by the first sliding bearing and the second sliding bearing.   The first slide bearing and the second slide bearing are PA, PBI, POM, PBT, PET, PPE, PC, UHMW-PE, PTFE, PPS, PI, PEEK, PAR, PSF, PEI, PAI, PES, The vertical shaft pump according to any one of claims 1 to 12, comprising a resin material, ceramics, or metal containing at least one of PF and PF.   The vertical shaft pump according to claim 13, wherein the first slide bearing and the second slide bearing include a resin material to which at least one of carbon fiber, glass fiber, carbon particle, glass particle, and graphite is added. .   A flow path for allowing water to pass through the gap between the first sliding portion and the first sliding bearing and the clearance between the second sliding portion and the second sliding bearing is formed. Item 15. The vertical shaft pump according to any one of Items 1 to 14.   The vertical shaft pump according to any one of claims 1 to 15, wherein the vertical shaft pump is configured to be installed in a drainage station.   The vertical shaft pump according to claim 15, further comprising a strainer at a water supply port for passing water through the flow path.   The vertical shaft pump according to any one of claims 1 to 17, further comprising a bearing case that holds the first sliding bearing on an inner circumferential surface and holds the second sliding bearing on an outer circumferential surface.   The vertical shaft pump according to any one of claims 1 to 18, wherein the second sliding portion is provided at an end portion of the rotating shaft.   The vertical shaft pump according to any one of claims 1 to 19, wherein the first sliding bearing and / or the second sliding bearing is configured to be divided in a circumferential direction.

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