WO2016009977A1

WO2016009977A1 - Vertical shaft pump

Info

Publication number: WO2016009977A1
Application number: PCT/JP2015/069985
Authority: WO
Inventors: 裕輔渡邊; 正治石井; 和彦杉山; 雄二中塩; 内田　義弘
Original assignee: 株式会社荏原製作所
Priority date: 2014-07-14
Filing date: 2015-07-13
Publication date: 2016-01-21
Also published as: SG11201610976PA; CN106662109A; MY176184A; CN106662109B; JP6320208B2; JP2016020648A

Abstract

Provided is a vertical shaft pump that, even for a high-capacity pump, allows easy replacement of submerged bearings, without lifting the pump, when the pump is in place, and improves the reliability of submerged bearings. This vertical shaft pump is provided with a guide casing (1), a suspended pipe (3) that suspends the guide casing (1) inside a water tank (5), a discharge curved pipe (4) that is connected to the top end of the suspended pipe (3), a impeller (10) that is accommodated inside the guide casing (1), and a rotating shaft (6) to which the impeller (10) is fixed. The rotating shaft (6) is rotatably supported by a submerged bearing unit (12) and an exterior bearing (11). The submerged bearing unit (12) is positioned below the impeller (10), and supports the bottom end of the rotating shaft (6). The rotating shaft (6) extends from the exterior bearing (11) through the impeller (10) without passing through bearings other than the exterior bearing (11). The submerged bearing unit (12) has an inner contact bearing that supports a sliding part of the rotating shaft (6) on the bearing inner circumferential surface, and has an outer contact bearing that supports the sliding part of the rotating shaft (6) on the bearing outer circumferential surface.

Description

Vertical shaft pump

The present invention relates to a vertical pump that pumps liquids such as river water and drainage, and more particularly to a vertical pump that can improve the durability and maintenance of a bearing that supports a rotating shaft and can easily replace the bearing.

FIG. 1 is a schematic diagram showing a conventional vertical shaft pump. As shown in FIG. 1, generally, a vertical shaft pump has a pump base 514, and the pump base 514 is installed on a pump installation floor 500 at the upper part of a water tank. A guide casing 506 that houses the impeller 504 is suspended from the pump installation floor 500 via the suspension pipe 502. The impeller 504 is fixed to a rotating shaft 509, and the rotating shaft 509 is rotatably supported by an outer bearing 510 and an underwater bearing 508.

Since such a vertical shaft pump is operated in a state where the impeller 504 and the underwater bearing 508 are immersed in water, the members gradually wear and corrode as the usage time elapses. For this reason, the vertical shaft pump is regularly inspected to check the wear state of the bearing portion (the outer bearing 510 and the underwater bearing 508) and the impeller 504, and the corrosion state of the guide casing 506. It is necessary to repair or replace the member. Among these members, damage and wear of the underwater bearing 508 cause abnormal vibration of the pump, and eventually cause a failure of the pump (impossible operation). For this reason, the inspection of the underwater bearing 508 is one of important inspection items.

立 As vertical shaft pump inspection and maintenance methods, 1) a method in which the pump is installed and 2) a method in which the pump is pulled up are known. In the inspection method 1), the inspection can be performed without raising the pump, so the cost is low and the period for inspection and maintenance can be shortened. However, for example, when the underwater bearing 508 of the vertical shaft pump is submerged in the water, it is difficult to appropriately measure or detect the wear state of the underwater bearing 508 by the method 1) above, and the underwater bearing 508 is replaced. I can't do that either. Even when the water in the water tank is drained and dried, the underwater bearing 508 is located above (the discharge side) of the impeller 504, so that the underwater bearing 508 cannot be inspected, maintained, or replaced. That is, even if the water in the water tank is drained and the bearing portion is exposed to the atmosphere, satisfactory inspection and maintenance cannot be performed due to the problem of the installation position of the bearing.

Therefore, a method has been proposed in which vibrations of the outer bearing 510 and the pump base 514 that can be measured on the ground are measured to indirectly estimate the state of the underwater bearing 508 (see Patent Documents 1 and 2). However, in this method, since measurement is not performed near the underwater bearing 508 serving as a vibration source, it is difficult to measure abnormal vibration due to wear of the underwater bearing due to various damping effects from the vibration source to the measurement point. Can not properly judge damage and wear situation.

On the other hand, according to the method 2), it is possible to appropriately measure or detect the wear state of the underwater bearing 508, and it is also possible to replace the underwater bearing 508. For this reason, in order to confirm the wear of the submerged bearing 508 of the vertical shaft pump, the method 2) has been conventionally performed.

However, the above method 2) is expensive and requires a long time for inspection and maintenance. For example, when a vertical shaft pump is lifted using an overhead crane, a mechanical engineer, an operator, a crane operator, and the like who are inspectors are required, and considerable work costs are required for lifting. Also, lifting and reassembling a heavy pump can be a dangerous operation.

Also, the lifting and inspection work requires inspection and maintenance after the lifting, and then undergoes the steps of re-installation, centering, and trial operation, which requires a considerable number of days. In addition, depending on the machine, it is necessary to keep the required amount of water drained even during inspection and maintenance, while the pump being inspected cannot be operated during the inspection period. It is necessary to secure drainage capacity by installing

Therefore, as shown in Patent Document 3, there has been proposed a vertical shaft pump having a structure in which a rotating shaft is supported by two of an underwater bearing disposed below an impeller and an outer bearing above a pump installation floor. According to this structure, since the underwater bearing is located below the impeller (suction side), the wear state of the underwater bearing can be visually inspected from the suction port, and the underwater bearing can be easily replaced. Can do.

However, pumps are required to have a large amount of water and a high head (increase in capacity). In recent years, in response to an increase in capacity, a load (load) applied to an underwater bearing provided only in the lower part is large. Thus, the bearing itself becomes large and heavy. In this case, there is a problem that workability from below the impeller deteriorates. Further, as the capacity of the pump is increased, the shaft diameter of the rotating shaft is increased and the peripheral speed of the bearing contact surface is increased.

Moreover, in patent document 4, as a technique with respect to the said subject, further providing an underwater bearing (intermediate bearing) between the outer bearing of a pump and the underwater bearing installed under the impeller, and this intermediate bearing is made into a split structure. An operator can enter the pump and replace the bearing. However, since the inside of the pump is narrow and works at a high place, problems of workability and safety remain.

Japanese Patent No. 3567140 JP 2004-218578 A Japanese Patent No. 4456579 JP 2012-137074 A

The present invention has been made in view of such problems of the prior art. Even in a large-capacity pump, the submersible bearing can be easily replaced with the pump installed without pulling up the pump. An object of the present invention is to provide a vertical shaft pump with improved reliability of the underwater bearing.

A vertical shaft pump according to a first aspect of the present invention includes an impeller, a rotating shaft that extends through the impeller and to which the impeller is fixed, an outer bearing that supports the rotating shaft, and an impeller A bearing unit that is provided below and supports the rotating shaft that passes through the impeller, and the rotating shaft passes through the impeller from the outer bearing without a bearing other than the outer bearing. The bearing unit includes a first bearing that supports the sliding portion of the rotating shaft on a bearing inner peripheral surface, and a second bearing that supports the sliding portion of the rotating shaft on a bearing outer peripheral surface.

According to the vertical pump according to the second embodiment of the present invention, in the vertical pump according to the first embodiment, the bearing unit is removably attached to the lower side of the impeller.

According to the vertical pump according to the third aspect of the present invention, in the vertical pump according to the first or second aspect, the first bearing and the second bearing are configured to be detachable below the impeller. Is done.

According to the vertical pump according to the fourth aspect of the present invention, in the vertical pump according to any one of the first to third aspects, it has a protective cover provided below the bearing unit, and the protective cover includes the bearing There is a small side-facing hole to guide the water flow to the unit.

According to the vertical pump according to the fifth aspect of the present invention, in any of the vertical pumps according to the first to fourth aspects, the first bearing and the second bearing are made of the same material, The material is composed of a resin or a resin composite material.

According to the present invention, the vertical shaft pump extends from the outer bearing through the impeller without any bearing other than the outer bearing, and the bearing receives the rotating shaft below the impeller. The bearing unit includes a first bearing that supports the sliding portion of the rotating shaft on the bearing inner peripheral surface, and a second bearing that supports the sliding portion of the rotating shaft on the outer peripheral surface of the bearing. The stability of submersible bearings is also improved in this type of pump, enabling stable operation of the pump, enabling downsizing of submersible bearings, and maintenance such as inspection work and replacement work without lifting the pump. It is possible to easily perform work with high workability and reliability in an as-is state.

It is a schematic diagram which shows the conventional vertical shaft pump. It is a schematic diagram which shows the vertical shaft pump in one Embodiment of this invention. It is a longitudinal cross-sectional schematic diagram explaining the principle of a bearing unit. It is sectional drawing in the XX 'cross section shown in FIG. It is a figure which shows operation | movement of the bearing unit at the time of dry operation. It is a figure which shows operation | movement of the bearing unit at the time of drainage operation. It is the figure which compared the vibration speed when the vertical shaft pump provided with the bearing unit performed dry operation with the case of the conventional bearing apparatus. It is the figure which compared the bearing temperature when the vertical shaft pump provided with the bearing unit performed dry operation with the case of the conventional bearing apparatus. It is the figure compared with the case of the conventional bearing apparatus about the vibration speed when carrying out drainage operation of the vertical shaft pump provided with the bearing unit. It is a longitudinal cross-sectional schematic diagram which shows the conventional bearing apparatus. It is a structure sectional view of the underwater bearing unit in one embodiment of the present invention. It is structure sectional drawing of the underwater bearing unit in other embodiment. It is structure sectional drawing of the underwater bearing unit in other embodiment. It is sectional drawing of an intermediate bearing unit cover. It is structure sectional drawing of the underwater bearing unit in other embodiment. It is structure sectional drawing of the underwater bearing unit in other embodiment.

Hereinafter, embodiments of the vertical shaft pump according to the present invention will be described in detail with reference to FIGS. 2 to 16. 2 to 16, the same or corresponding components are denoted by the same reference numerals, and redundant description is omitted. In the following description, “upper” means the upper side (discharge side) in the state where the vertical shaft pump is installed, and “lower” means the lower side (suction side) in the state where the vertical axis pump is installed.

FIG. 2 is a schematic diagram showing a vertical shaft pump according to an embodiment of the present invention. As shown in FIG. 2, the vertical pump is connected to a guide casing 1 having a suction bell mouth 1a and a discharge bowl 1b, a suspension pipe 3 for suspending the guide casing 1 in a water tank 5, and an upper end of the suspension pipe 3 The discharge curved pipe 4, the impeller 10 accommodated in the guide casing 1, and the rotating shaft 6 to which the impeller 10 is fixed are provided.

The suspension pipe 3 extends downward through an insertion hole 24 formed in the pump installation floor 22 above the water tank 5 and is fixed to the pump installation floor 22 via a pump base 23 provided at the upper end of the suspension pipe 3. Has been. The rotating shaft (vertical shaft) 6 extends in the vertical direction through the discharge bent tube 4 and the suspension tube 3, and the lower end thereof is located in the guide casing 1. A pump casing 2 is constituted by the guide casing 1 and the suspension pipe 3. The upper floor F that is an area above the pump installation floor 22 is an area that can be inspected at all times, and the water tank section U that is an area below the pump installation floor 22 is an area that is submerged.

As shown in FIG. 2, the suction bell mouth 1a has an opening on the lower side (suction side), and the upper end of the suction bell mouth 1a is fixed to the lower end of the discharge bowl 1b. The impeller 10 is fixed to the lower part of the rotating shaft 6, and the impeller 10 and the rotating shaft 6 rotate integrally. The impeller 10 has a plurality of blades, and a plurality of guide vanes 14 are disposed above (the discharge side) the impeller 10. These guide vanes 14 are fixed to the inner peripheral surface of the guide casing 1 and the outer peripheral surface of the bowl bush 13.

Further, the rotating shaft 6 is rotatably supported by the underwater bearing unit 12 and the outer bearing 11. The underwater bearing unit 12 is located below (the suction side) of the impeller 10 and supports the lower end of the rotating shaft 6. The underwater bearing unit 12 is supported by a support member 15 fixed to the inner peripheral surface of the suction bell mouth 1a. In addition, the underwater bearing is not arranged between the outer bearing 11 and the underwater bearing unit 12 including the inside of the bowl bush 13. The outer bearing 11 is provided on the upper part (outside) of the discharge curved pipe 4 and supports the upper part (one end) of the rotating shaft 6. The rotating shaft 6 extends through the impeller 10 from the outer bearing 11 without any bearing other than the outer bearing 11. The underwater bearing unit 12 is disposed on the radially outer side of the rotating shaft 6 (around the rotating shaft 6), and is an inscribed bearing (first bearing) that supports the sliding portion of the rotating shaft 6 on the bearing inner peripheral surface. And a circumscribed bearing (second bearing) that is disposed on the radially inner side of the rotating shaft 6 and supports the sliding portion of the rotating shaft 6 on the outer peripheral surface of the bearing.

The first bearing and the second bearing provided in the underwater bearing unit 12 are so-called slide bearings that support the rotating shaft while slidingly contacting the rotating shaft 6 during steady operation of the pump. The outer bearing 11 is configured not only to receive a radial load but also to receive a thrust load. The outer bearing 11 may be a single bearing capable of receiving both a radial load and a thrust load, or a combination of a radial bearing capable of receiving a radial load and a thrust bearing capable of receiving a thrust load. There may be.

As shown in FIG. 2, the rotating shaft 6 protrudes upward from the discharge curved pipe 4. The upper end of the rotary shaft 6 is connected to the drive shaft 42 of the speed reducer 41 via a universal shaft joint 45. Furthermore, the speed reducer 41 is connected to a drive source 43. As the drive source 43, a diesel engine, a gas turbine, a motor, or the like can be used. Note that the speed reducer 41 may not be used.

When the impeller 10 is rotated by the drive source 43 via the rotating shaft 6, water (handling liquid) in the water tank 5 is sucked from the suction bell mouth 1 a, and the discharge bowl 1 b, the suspension pipe 3, and the discharge bent pipe 4 are drawn. It is transferred to the discharge pipe 20 through. During the drainage operation of the vertical shaft pump, the impeller 10 and the underwater bearing unit 12 are located below the water surface.

In the conventional vertical shaft pump shown in FIG. 1, since the submersible bearing 508 is housed in the bowl bush, it is difficult to replace the submersible bearing 508 with the vertical pump installed. In the present embodiment, since the underwater bearing unit 12 is disposed below the impeller 10, if water inside the water tank 5 is removed and an operator enters the lower part of the vertical shaft pump, The amount of wear and damage of the bearing unit 12 can be easily determined, and the underwater bearing unit 12 can be easily replaced.

As described above, since the submersible bearing unit 12 can be inspected and replaced without lifting the vertical shaft pump, the cost required for lifting the vertical shaft pump can be reduced, and the downtime during inspection and replacement can be greatly increased. Can be shortened. Therefore, the economical efficiency and reliability of the pump station can be improved. Moreover, since the position of the underwater bearing unit 12 is lower than the conventional position and is located below the impeller 10, the underwater bearing unit 12 can be surely submerged during the operation of the pump. Therefore, the water film formed between the underwater bearing unit 12 and the rotating shaft 6 can suppress wear of the underwater bearing unit 12 and improve the durability of the underwater bearing unit 12.

Next, the first slide bearing and the second slide bearing will be described. FIG. 3 is a schematic longitudinal sectional view illustrating the principle of the bearing unit. This bearing unit has a sleeve 31 on the outer periphery of the rotary shaft 30. The material of the sleeve 31 is practically made of cemented carbide or stainless steel. A hollow cylindrical first slide bearing 44 is provided on the outer peripheral side of the sleeve 31. That is, the sleeve 31 contacts and slides inside the first slide bearing 44. The material of the first plain bearing 44 is practically made of a resin material, ceramics, sintered metal, or surface-modified metal. The outer peripheral surface (first sliding portion 46) of the sleeve 31 faces the inner peripheral surface (slip surface) of the first slide bearing 44 through a very narrow first clearance 47, and the first slide bearing. It is configured to slide with respect to 44 sliding surfaces. The outer peripheral portion of the first plain bearing 44 is fixed to the inner peripheral surface of the substantially cylindrical bearing case 32. The material of the bearing case 32 is practically made of metal or resin.

Further, a hollow cylindrical second sliding bearing 39 is provided on the outer peripheral surface of the bearing case 32. The material of the second plain bearing 39 is practically made of a resin material, ceramics, sintered metal, or surface-modified metal.

A substantially cylindrical sleeve case 38 is fixed to the rotating shaft 30 by fixing means 33a such as a fixing pin or a bolt, and the sleeve case 38 rotates with the rotating shaft 30 as the rotating shaft 30 rotates. It is configured. A sleeve 37 is provided on the inner peripheral surface of the sleeve case 38, and the inner peripheral surface (second sliding portion 36) of the sleeve 37 is the second narrower than the outer peripheral surface (sliding surface) of the second slide bearing 39. Are arranged so as to face each other through the clearance 48 and slide with respect to the sliding surface of the second sliding bearing 39. That is, the sleeve 37 circumscribes and slides outside the second slide bearing 39. The

sleeves

31 and 37 are generally installed on the outer periphery of a shaft member or the like, but in the present application, in order to make the configuration of the bearing unit easy to understand, for the sake of convenience, the

sleeves

31 and 37 bear the main bearing material. First and second sliding bearings are used, and the opposed sliding members are referred to as sleeves.

The above is the configuration of the bearing unit. The bearing unit is fixed to a support member 35 or the like connected to a casing such as a pump via a flange portion 32a of the bearing case 32 by fixing means 33b such as a bolt. In the above example, the sleeve 31 is held on the outer periphery of the rotating body (rotating shaft 30), and the non-rotating slide bearing corresponding to the outer peripheral side of the sleeve 31 is used as the first slide bearing 44. On the other hand, a sleeve 37 is provided on the inner circumference of the rotating body (sleeve case 38), and a non-rotating slide bearing corresponding to the inner circumference side of the sleeve 37 is used as a second slide bearing 39. However, a slide bearing may be held on the outer periphery of the rotating body (rotating shaft 30), and a sleeve may be provided on the corresponding non-rotating body. Further, the first slide bearing holds the sleeve on the outer periphery of the rotating body, and the second slide bearing holds the slide bearing on the outer periphery of the rotating body in a state where the corresponding slide bearing is on the non-rotating side. It is possible that the corresponding sleeve is on the non-rotating side and vice versa.

In consideration of the case where the bearing unit is used, for example, in a drainage pump such as a vertical shaft pump and used in an underwater environment, the sleeve case 38 is supplied with water containing slurry or the like in the first clearance 47 and the second clearance. A water supply port 40 for passing water through the clearance 48 is provided. The water that has flowed into the water supply port 40 passes through the first clearance 47 and the second clearance 48 as flow paths. In this way, a flow path for allowing water to pass through the first clearance 47 and the second clearance 48 is formed, and the first clearance 47 and the second clearance 48 also function as a flow path. Water quickly flows into the first clearance 47 and the second clearance 48 without staying, and the functions of the first slide bearing 44 and the second slide bearing 39 can be exhibited quickly.

Further, the first slide bearing 44 and the second slide bearing 39 support the sleeve 31 and the sleeve 37 under dry conditions at the time of start-up, and the sleeve 31 and the sleeve 37 through a very thin liquid film under drainage conditions. To support. Here, the dry condition refers to a condition in which the atmosphere of the first slide bearing 44 and the second slide bearing 39 in operation is in the air without liquid lubrication, and the dry operation is performed under the conditions. That means.

In order to suppress steady swinging of the rotating shaft 30 and to suppress the load applied to the first slide bearing 44 and the second slide bearing 39 by swinging, the diameter clearance dimension (the first clearance 47) The inner diameter of the first slide bearing 44—the outer diameter of the sleeve 31) and the diameter clearance dimension of the second clearance 48 (the inner diameter of the sleeve 37—the outer diameter of the second slide bearing 39) are the same as those of the first slide bearing 44. It is preferable that the inner diameter is 1/1000 or more and 1/100 or less and the outer diameter of the second slide bearing 39 is 1/1000 or more and 1/100 or less. When the dimensions of the first clearance 47 and the second clearance 48 are larger than these ranges, the steady swinging of the rotating shaft 30 becomes large, and the swinging causes the first sliding bearing 44 and the second sliding. The load applied to the bearing 39 is also increased, and stable operation may be difficult. Further, when the dimensions of the first clearance 47 and the second clearance 48 are smaller than these ranges, the first clearance 47 and the second clearance 48 are blocked by foreign matter, or the first slide bearing 44 and the second clearance 48 are closed. In some cases, the second slide bearing 39 may be seized due to friction with foreign matter.

The diameter clearance dimension of the first clearance 47 and the diameter clearance dimension of the second clearance 48 are preferably the same, but the first sliding bearing 44, the second sliding bearing 39, the sleeve 37, or the sleeve 31 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 48 to the diameter clearance dimension of the first clearance 47 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 sliding bearing 44, the second sliding bearing 39, the sleeve 37, or the sleeve 31 is further fixed via a cushioning material such as rubber (see FIG. 11 and the like), the cushioning is performed. The first slide bearing 44 and the second slide bearing 39 can simultaneously contact the sleeve 31 and the sleeve 37 at the same time, even if the dimensions are not in the above-mentioned range due to the deformation of the material, and the function of the present invention is exhibited.

FIG. 4 is a cross-sectional view taken along the line XX ′ shown in FIG. As shown in the figure, the centers of the outer peripheral surface of the sleeve 31, the inner peripheral surface of the first slide bearing 44, the outer peripheral surface of the second slide bearing 39, and the inner peripheral surface of the sleeve 37 substantially coincide with the central axis O. Is configured to do. In FIG. 4, the dimensions of the first clearance 47 and the second clearance 48 are shown enlarged for the sake of convenience.

FIG. 5 is a diagram illustrating the operation of the bearing unit during the dry operation. When the rotating shaft 30 rotates, the sleeve 31 fixed to the rotating shaft 30 and the sleeve 37 fixed to the sleeve case 38 also rotate. Under dry conditions, when the outer peripheral surface of the sleeve 31 contacts the first slide bearing 44 at point A, a bearing reaction force _FAN is generated on the rotary shaft 30. By this bearing reaction force _FAN , a frictional force _FAF is generated in a direction opposite to the rotation direction of the rotating shaft 30, and this frictional force _FAF causes a whirling vibration in the direction opposite to the rotating direction in the rotating shaft 30. Stabilization power.

On the other hand, when the sleeve 37 contacts the second sliding bearing 39 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. In the system of the rotary shaft 30, the frictional force _FAF and the frictional force _FBF are canceled out, so that the rotary shaft 30 can rotate stably. Further, since the load (bearing reaction force) related to the rotating shaft 30 is distributed to the points A and B, the frictional force applied to the slide bearing is also distributed. As a result, heat generation due to friction is reduced, and the temperature rise of the bearing during dry operation is suppressed.

FIG. 6 is a diagram illustrating the operation of the bearing unit during the drainage operation. The first clearance 47 and the second clearance 48 are filled with water, and this water constitutes a liquid film 49 and a liquid film 50, respectively, whereby the bearing unit functions as a fluid lubrication bearing unit. This time the liquid film 49, the circumferential direction of the pressure nonuniformity due to the rotation of the rotating shaft 30 occurs, as a result, the radial fluid forces F _AR and the circumferential fluid force F _AT occurs in the rotation shaft 30. 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 this liquid film on a vertical rotating shaft, the inner surface of the bearing has been formed into 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 the present bearing unit, in the liquid film 50 in the second clearance 48, circumferential pressure non-uniformity occurs due to the rotation of the sleeve 37, and as a result, the radial fluid force F _BR and the circumferential pressure are applied to the rotating shaft 30. A directional fluid force _FBT is 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 49, destabilizing forces due to the liquid film 50 is canceled, the rotary shaft 30 by a destabilizing force It can rotate stably without generating vibration.

As described above, the bearing unit is a sliding bearing that always slides on the sliding surface and supports the rotating shaft in both the normal operation during the dry operation and the drain operation, and the contact of the first sliding bearing, Since the frictional force acting on the contact point of the second sliding bearing cancels out, vibration of the rotating shaft due to the destabilizing force can be suppressed, and stable rotation of the rotating shaft can be maintained.

FIG. 7 is a diagram showing the vibration speed when the bearing unit shown in FIG. 3 is provided in the vertical shaft pump and the dry operation without lubrication or cooling with water is performed in the atmosphere in the atmosphere. For comparison, the vibration speed when the vertical shaft pump (conventional structure) including the conventional bearing device shown in FIG.

10 has a sleeve 29 on the outer periphery of the rotary shaft 25. The conventional bearing device shown in FIG. A hollow cylindrical slide bearing 28 is provided on the outer peripheral side of the sleeve 29. The outer peripheral surface of the sleeve 29 is configured to face the inner peripheral surface (slip surface) of the slide bearing 28 through a very narrow clearance and slide relative to the slide bearing 28. The diameter and the number of rotations of the rotating shaft 25 and the material of the sleeve 29 and the plain bearing 28 shown in FIG. 10 are the same conditions as the bearing unit shown in FIG.

As shown in FIG. 7, the vertical pump (this embodiment) having the bearing unit shown in FIG. 3 is more constant from the start to the start than the vertical pump having the conventional bearing device. It can be seen that the system is operated at a lower vibration speed than the conventional structure.

FIG. 8 is a diagram showing the bearing temperature when the bearing unit shown in FIG. 3 is provided in the vertical shaft pump and the dry operation is performed. For comparison, the bearing temperature when the vertical shaft pump (conventional structure) including the conventional bearing device shown in FIG.

As shown in FIG. 8, the vertical pump (this embodiment) having the bearing unit shown in FIG. 3 is more constant from the start to the stop than the vertical pump having the conventional bearing device. It can be seen that a lower bearing temperature is maintained compared to the conventional structure.

As shown in FIGS. 7 and 8, 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 provided with the present bearing unit, as described with reference to FIG. 5, it is possible to reduce vibration and frictional force and to suppress an increase in bearing temperature.

FIG. 9 is a diagram showing the vibration speed when the vertical axis pump is provided with the bearing unit shown in FIG. 3 and the drainage operation is performed. During the drainage operation, the bearing unit is submerged in water. For comparison, the vibration speed when the vertical shaft pump (conventional structure) including the conventional bearing device shown in FIG. Note that the results shown in FIG. 9 are obtained by measuring the vibration at the time when the operation condition of the vertical shaft pump is operated under a condition where vibration is likely to occur.

As shown in FIG. 9, the vertical pump (this embodiment) provided with the bearing unit shown in FIG. 3 is more constant from the start to the stop than the vertical pump provided with the conventional bearing device. It can be seen that the system is operated at a lower vibration speed than the conventional structure.

As described above, according to the bearing unit shown in FIG. 3, the first slide bearing 44 and the second slide bearing 39 are rotated by the rotating body (sleeve) due to the swing of the shaft of the rotary shaft 30 during the dry operation. 31 and the sleeve 37) collide with each other because the frictional forces act in opposite directions to cancel each other at the time of the collision, thereby suppressing the divergence of the swing of the rotating shaft 30 and preventing the vibration due to destabilization. be able to. In addition, it is possible to reduce friction caused by this vibration and suppress an increase in bearing temperature.

Since the bearing unit shown in FIG. 3 has the first slide bearing 44 and the second slide bearing 39, 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.

Further, the bearing unit shown in FIG. 3 holds the first slide bearing 44 on the inner peripheral surface of the bearing case 32 and the second slide bearing 39 on the outer peripheral surface thereof. A compact structure can be obtained.

By the way, in the vertical shaft pump including the bearing unit according to the present embodiment, the portions (the sleeve 31 and the sleeve 37) located in the water of the rotary shaft 30 are supported by the first slide bearing 44, the second slide bearing 39, and the like. This is done only with plain bearings. That is, a rolling bearing such as a ball bearing or a roller bearing is not suitable for an underwater bearing of a rotating machine that performs drainage operation, and the effect of this embodiment can be achieved by a sliding bearing.

(Fitting / removal configuration: unitized)
Next, the bearing unit structure provided in the vertical shaft pump according to the present invention will be described. The principle of this bearing unit is the same as the principle of the bearing unit described in FIGS. FIG. 11 shows the bearing unit attached to the support member 15 fixed to the inner peripheral surface of the suction bell mouth 1a of the vertical shaft pump in FIG. The rotating shaft 6 has a cylindrical structure with a hollow end. The bearing unit includes a first slide bearing 52 and a second slide bearing 57. A sleeve 51 (corresponding to an example of a sliding portion of the rotating shaft) corresponding to the first slide bearing 52 disposed on the radially outer side of the rotating shaft 6 (around the rotating shaft 6) is a rotating shaft below the impeller. 6 is provided on the outer periphery of the end portion. A sleeve 55 (corresponding to an example of a sliding portion of the rotating shaft) corresponding to the second sliding bearing 57 is provided inside the hollow cylindrical structure at the end of the rotating shaft 6 with a cushioning material 56 interposed therebetween. The sleeve 55 and the buffer material 56 corresponding to the second sliding bearing 57 are fixed to the rotating shaft 6 by the pressing plate 58.

The first plain bearing 52 is held by a substantially cylindrical first bearing case 54 via a buffer material 53. The first bearing case 54 is fixed to the support member 15. The first bearing case 54 has a substantially disc-shaped collar portion 54a. A flange portion 54a is removably attached to the lower surface of the support member 15 with a bolt 61a so that the first bearing case 54 can be removed vertically downward (suction side) of the pump. The second sliding bearing 57 is disposed immediately below the first sliding bearing 52, and is fixed to the first bearing case 54 by a substantially cylindrical or cylindrical second bearing case 60. The second bearing case 60 has a substantially disc-shaped collar portion 60a, and is detachably attached to the lower surface of the first bearing case 54 of the collar portion 60a by a bolt 61b.

As described above, by dividing the first bearing case 54 and the second bearing case 60, it is possible to perform work only by removing the device having the minimum size and load in the bearing inspection work and the bearing replacement work. .

For example, in the inspection work for observing the wear situation of the bearing, even when the vertical shaft pump has a large capacity and the size of the bearing unit is large, the second bearing case 60 is divided from the first bearing case 54, The bearing inspection / maintenance can be improved by removing only the bearing case 60 of the second bearing. On the contrary, after the inspection, it is only necessary to assemble the second bearing case 60 into the first bearing case 54, so that workability can be improved.

In this case, in addition to improving workability of removal and assembly, it is possible to reliably align the cores of the first slide bearing 52 and the second slide bearing 57 with the first bearing case 54 as a base. The operation state after the inspection work can be maintained in the same state as the operation state before the work, and a highly stable bearing unit can be configured.

When the bearing is replaced, the first bearing case 54 is removed, so that the first slide bearing 52 and the second slide bearing 57 can be removed as a unit at the same time. Can be improved. When the diameter of the rotary shaft 6 is relatively small, the size of the device is also relatively small. Therefore, the first bearing case 54 and the second bearing case 60 are not divided parts and are shown in FIG. As described above, it may be an integrated bearing case 62 that holds the first slide bearing 52 and the second slide bearing 57. The integral bearing case 62 has a substantially disc-shaped collar portion 62a, and the collar portion 62a can be fitted to and detached from the lower surface of the support member 15 with a bolt 61c so that the collar portion 62a can be removed vertically below the pump (suction side). Attached to.

Further, the second bearing case 60 shown in FIG. 11 and the integrated bearing case 62 shown in FIG. 12 are preferably provided with a plurality of water supply / drain ports (holes) 59. By providing the water supply / drain port 59, the water flow of the pump can be reliably guided to the surfaces of the first slide bearing 52 and the second slide bearing 57, and the friction of the bearing surface due to the internal water on the bearing surface can be reduced. The life can be improved and vibration can be suppressed.

FIG. 13 is a view showing another embodiment of the bearing unit provided in the vertical shaft pump according to the present invention. The structure of the bearing unit, the outer diameter D ₂ of the rotary shaft 6 is applied to the outer diameter D ₁ greater than a large vertical shaft pump of the rotary shaft 6 shown in FIG. 11. The second slide bearing 57 is installed on the inner surface of the hollow cylindrical structure of the rotary shaft 6 on the substantially horizontal XX plane at the installation position of the first slide bearing 52. As described above, the first slide bearing 52 and the second slide bearing 57 are arranged on the same horizontal plane without being separated in the vertical direction (axial direction), so that the bearing contact at the position facing the same horizontal plane is achieved. Therefore, the bearing sliding stability can be improved without being affected by the bending of the shaft caused by the rotation of the long rotating shaft 6.

Further, by arranging the first slide bearing 52 and the second slide bearing 57 on the same horizontal plane, it becomes possible to shorten the vertical (axial) length of the bearing unit, and the bearing unit is configured compactly. can do. Since the bearing unit becomes compact, there are fewer parts that obstruct the flow of the handling liquid, and it is possible to reduce adverse effects on pump performance such as a decrease in pump efficiency and an increase in deadline shaft power.

(Unit cover)
FIG. 14 is a view showing a protective cover provided in the vertical shaft pump of the present invention. The protective cover 63 has a substantially spherical shape at the tip, and is attached to the second bearing case 60 by a fixing member 64 so as to be detachable. Further, the protective cover 63 is provided with a water supply / drain port (small hole) 63a for supplying / draining the liquid handled by the pump in the horizontal direction (to face the side). By configuring the bearing unit in this way, it is possible to reduce the head loss caused by the bearing unit that is installed below the pump rotating body and directly receives the water flow, and it is possible to prevent deterioration of the pump performance (efficiency). It becomes.

Further, by providing the water supply / drainage port 63a in the protective cover 63 in the horizontal direction (perpendicular to the axial direction of the rotary shaft 6), it is possible to use a drainage pump for rivers or sewers in which slurry is contained in the handling liquid. It is possible to prevent the slurry from entering the bearing portion and suppress the wear of the bearing. In addition, since the main water supply / drain port 63a drains the water in the bearing portion to the water absorption tank side when the pump is stopped, it is effective in preventing slurry accumulation inside the pump bearing.

In addition, since the protective cover 63 is detachably attached to the second bearing case 60 by the fixing member 64, the protective cover 63 is removed by removing the protective cover 63 during the inspection of the bearing or during the removal / attachment operation. The influence on these operations can be eliminated. In FIG. 14, the protective cover 63 is detachably attached to the second bearing case 60, but may be detachably attached to the first bearing case 54 or the support member 15.

Next, another type of bearing unit structure according to the present invention will be described. As shown in the embodiment shown in FIG. 13, the sleeve 51 is provided on the outer surface of the rotary shaft 6, and the first sliding bearing 52 corresponding to the sleeve 51 is held by the first bearing case 54 outside the sleeve 51. in the peripheral speed the larger the outer diameter D ₂ of the rotary shaft 6 is increased, the load of the sliding portion increases. When the outer diameter D ₃ of the sliding portion of the second plain bearing 57 in the embodiment shown in FIG. 13 is extremely smaller than the outer diameter D ₂ of the rotating shaft 6, from the center to the outer periphery of the sleeve 51. And the distance from the center to the outer periphery of the second slide bearing 57 are significantly different from each other, so that the second slide bearing 57 cannot receive the surface pressure from the sleeve 55. For this reason, the bearing reaction force of the second sliding bearing 57 is insufficient, and a difference occurs in the frictional forces in the opposite directions applied to the first sliding bearing 52 and the second sliding bearing 57.

Therefore, the bearing unit shown in FIGS. 15 and 16 has a sliding portion that does not directly depend on the diameter of the rotating shaft 6 while ensuring the maintenance such as the ease of replacement and inspection shown in the above description. The present invention provides a bearing unit structure capable of ensuring an optimum peripheral speed, an optimum surface pressure, and an optimum bearing reaction force.

FIG. 15 shows a bearing unit according to another embodiment of the present invention attached to a support member 15 fixed to the inner peripheral surface of the suction bell mouth 1a of the vertical shaft pump in FIG. A first bearing case 71 is fixed to the end of the rotating shaft 6 by a fixing member (bolt or the like) 70. The first bearing case 71 has a hollow cylindrical portion 71a, and a sleeve 55 (corresponding to an example of a sliding portion of the rotating shaft) is provided on the inner peripheral surface of the first bearing case 71 via a buffer material 56. The sleeve 55 and the buffer material 56 are fixed to the first bearing case 71 by a pressing plate 58. In addition, a first plain bearing 52 is provided on the outer peripheral surface of the cylindrical portion 71 a of the first bearing case 71. Since the first bearing case 71 is fixed to the rotating shaft 6, it rotates together with the rotating shaft 6.

On the other hand, a second bearing case 65 is fixed to the support member 15 by a fixing member (bolt or the like) 69. The second bearing case 65 includes a columnar portion 65 a inserted into a hollow portion (inside the cylinder) of the hollow cylindrical portion 71 a of the first bearing case 71, and a hollow cylindrical shape of the first bearing case 71. And a cylindrical portion 65b surrounding the outer periphery of the portion 71a. A second sliding bearing 57 is provided on the outer peripheral surface of the columnar portion 65a corresponding to the sleeve 55 provided on the inner peripheral surface of the hollow cylindrical portion 71a of the first bearing case 71 via a buffer material 56. Is provided. Further, on the inner peripheral surface of the cylindrical portion 65 b of the second bearing case 65, a sleeve 51 (through a buffer material 53 is provided corresponding to the first sliding bearing 52 provided in the first bearing case 71. Corresponding to an example of the sliding portion of the rotating shaft). The sleeve 51 and the buffer material 53 are fixed to the second bearing case 65 by a pressing plate 66.

The outer diameter D ₂ ′ of the sliding portion of the first sliding bearing 52 is smaller than the outer diameter D _{2 of} the rotating shaft 6, and when the rotating shaft 6 rotates, the peripheral speed of the sliding portion is that of the sliding member. It is set so that proper use can be continued. Further, the outer diameter D ₃ of the sliding portion of the second sliding bearing 57 is smaller than the outer diameter D ₂ ′ of the sliding portion of the first sliding bearing 52, but the second sliding bearing 57 is removed from the sleeve 55. It is the size of the range where the surface pressure can be properly received.

With such a configuration, the size of the first bearing case 71 and the second bearing case 65 can be made compact without depending much on the diameter of the rotating shaft 6. In maintenance, the first sliding bearing 52 and the second sliding bearing 57 can be inspected and replaced by removing only the second bearing case 65, so that workability is improved.

Further, in the present embodiment, the first bearing case 71 having sliding portions on the inner peripheral surface and the outer peripheral surface is fixed to the end of the rotating shaft 6, and the inner peripheral surface and the outer peripheral surface of the first bearing case 71 are fixed. A second bearing case 65 having a sliding portion corresponding to the sliding portion is fixed to a non-rotating fixed body such as the support member 15. Thereby, even if the diameter of the rotating shaft 6 is increased, the rotational peripheral speed of each sliding portion is suppressed to an appropriate range, the surface pressure applied to each sliding portion is also suppressed to an appropriate range, and the directions opposite to each other are suppressed. The friction force can be set within an appropriate range, and stable bearing performance can be exhibited.

FIG. 16 shows a bearing unit structure according to another embodiment of the present invention attached to a support member 15 fixed to the inner peripheral surface of the suction bell mouth 1a of the vertical shaft pump in FIG. A first bearing case 72 is fixed to the end of the rotating shaft 6 by a fixing member (bolt or the like) 77. The first bearing case 72 has a columnar portion 72a and a hollow cylindrical portion 72b surrounding the columnar portion 72a. A second slide bearing 57 (corresponding to an example of a sliding portion of the rotating shaft) is provided on the outer periphery of the columnar portion 72a, and a sleeve 51 (rotation) is provided on the inner surface of the cylindrical portion 72b via a buffer material 53. Corresponding to an example of a sliding portion of the shaft). The sleeve 51 and the buffer material 53 are fixed to the first bearing case 72 by a pressing plate 79. Since the first bearing case 72 is fixed to the rotating shaft 6, it rotates together with the rotating shaft 6.

On the other hand, a second bearing case 73 is fixed to the support member 15 by a fixing member (bolt or the like) 74. The second bearing case 73 has a cylindrical portion 73a inserted between the columnar portion 72a and the cylindrical portion 72b of the first bearing case 72. A sleeve 55 corresponding to the second sliding bearing 57 is provided on the inner peripheral surface of the cylindrical portion 73 a of the second bearing case 73 via a cushioning material 56. The sleeve 55 and the buffer material 56 are fixed to the second bearing case 73 by a pressing plate 80. A first plain bearing 52 corresponding to the sleeve 51 is provided on the outer peripheral surface of the cylindrical portion 73 a of the second bearing case 73.

The outer diameter D ₂ ′ of the sliding portion of the first sliding bearing 52 is smaller than the outer diameter D _{2 of} the rotating shaft 6, and when the rotating shaft 6 rotates, the peripheral speed of the sliding portion is that of the sliding member. It is set so that proper use can be continued. Further, the outer diameter D ₃ of the sliding portion of the second sliding bearing 57 is smaller than the outer diameter D ₂ ′ of the sliding portion of the first sliding bearing 52, but the second sliding bearing 57 has the sleeve 55. It is the size of the range where the surface pressure can be properly received.

The operational effects of the bearing unit of the embodiment shown in FIG. 16 are the same as the operational effects of the bearing unit shown in FIG.

(Advance standby, resin bearing)
As materials for the first slide bearing 52 and the second slide bearing 57 of this bearing unit, ceramics, resin, rubber, or the like can be used. In the standby standby pump that performs air operation and drainage operation, it can be used in an anhydrous state rather than a brittle material such as ceramics in order to prevent damage to the bearing due to a sudden change in operating state (including a sudden change in bearing temperature). A resin or a resin composite material is used. When such a resin bearing is used, since the resin bearing is inferior in wear resistance and has a large friction coefficient compared to a ceramic bearing, there arises a problem that the amount of heat generated by the bearing during air operation increases. However, by using the combination unit of the first slide bearing 52 and the second slide bearing 57 of the present invention, it is possible to suppress the amount of wear and heat generation.

In the bearing device and the bearing unit structure according to the present invention described above, it is not always necessary to provide a cushioning material on the opposite side of the sliding surface of the sleeve and each slide bearing. As mentioned above, although preferable embodiment of this invention was described, it cannot be overemphasized that this invention is not limited to the above-mentioned embodiment, and may be implemented with a different form within the range of the technical idea.

DESCRIPTION OF SYMBOLS 1 ... Guide casing 3 ... Suspension pipe | tube 4 ... Discharge curved pipe 6 ... Rotating shaft 10 ... Impeller 11 ...

Outer bearing

44, 52 ...

1st slide bearing

39, 57 ... 2nd slide bearing 63 ... Protective cover 63a ... Water supply / drainage

Claims

Impeller,
A rotating shaft extending through the impeller and to which the impeller is fixed;
An outer bearing that supports the rotating shaft;
A bearing unit provided below the impeller and supporting the rotating shaft penetrating the impeller, and
The rotating shaft extends through the impeller from the outer bearing without a bearing other than the outer bearing,
The bearing unit includes a first bearing that supports a sliding portion of the rotating shaft on a bearing inner peripheral surface, and a second bearing that supports a sliding portion of the rotating shaft on a bearing outer peripheral surface.
The vertical shaft pump according to claim 1, wherein the bearing unit is removably attached to the lower side of the impeller.
The vertical shaft pump according to claim 1 or 2, wherein the first bearing and the second bearing are configured to be fitted / removed below the impeller.
A protective cover provided below the bearing unit;
The vertical shaft pump according to any one of claims 1 to 3, wherein the protective cover has a small side hole for guiding a water flow to the bearing unit.
The first bearing and the second bearing are made of the same material,
The vertical pump according to any one of claims 1 to 4, wherein the material is made of a resin or a resin composite material.