WO2017212534A1

WO2017212534A1 - Vertical shaft pump

Info

Publication number: WO2017212534A1
Application number: PCT/JP2016/066822
Authority: WO
Inventors: 裕輔渡邊; 正治石井; 真小宮; 内田　義弘
Original assignee: 株式会社荏原製作所
Priority date: 2016-06-07
Filing date: 2016-06-07
Publication date: 2017-12-14
Also published as: JP6745876B2; JPWO2017212534A1

Abstract

Provided is a vertical shaft pump in which the centrifugal whirling of a rotational shaft, which occurs with increased frequency and intensity as rotational shafts are lengthened, has been appropriately reduced for the entire rotational shaft.　Specifically provided is a vertical shaft pump comprising a rotational shaft, a pump casing that accommodates at least a part of the rotational shaft, and an impeller attached to the rotational shaft. The vertical shaft pump further comprises a first slide bearing device that is disposed on the interior of the pump casing and supports the rotational shaft, and a second slide bearing device that is disposed on the exterior of the pump casing and supports the rotational shaft. The first slide bearing device is used when the sliding surface is in an air environment during in-air operation. The second slide bearing device is normally used when the sliding surface is in a liquid environment.

Description

Vertical shaft pump

The present invention relates to a vertical shaft pump. More specifically, operation management is performed under dry conditions such as a vertical shaft pump that performs management operation by rotating the rotary shaft of the pump while water is not filled into the pump casing of the vertical shaft pump or a preceding standby operation pump. The present invention relates to a vertical shaft pump.

In recent years, due to the progress of urbanization, the heat island phenomenon has occurred due to the decrease in green space, the concrete on the road surface, and the expansion of asphalt. 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 should have rainwater before reaching the drainage pump station in order to prevent inundation damage due to delays in starting. Pre-standby operation to be started is performed.

FIG. 1 is a partial schematic diagram of a vertical shaft pump that performs a preliminary standby operation. Even if the water level of the water tank 100 is equal to or lower than the minimum operating water level LWL, the water tank 100 of the drainage pump station is provided with an impeller 22 at the tip of the rotary shaft 10 arranged vertically and the air is sucked into the impeller 22 together with water. A vertical shaft pump 3 capable of continuing the operation (preceding standby operation) is disposed. This vertical shaft pump 3 is provided with a through hole 5 in the side surface 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. ing. 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. As described above, in order to prevent inundation damage due to a delay in starting, for example, for a rainwater drainage in a large city, a vertical shaft pump is started in advance based on rainfall information or the like regardless of the suction water level (A: air operation). When rainwater reaches the drainage station, as the water level rises from a low water level, the water level reaches the impeller position, and the vertical shaft pump is an operation that stirs water with the impeller from an empty operation (air operation) (B: air water) Agitation operation), and a full amount 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 air supplied through the through-holes. Migrate to When the water level drops from the high water level, the operation shifts from the full operation to the operation of gradually reducing the water amount while sucking in the air supplied through the through holes together with the water (C: air-water mixing operation). 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. Note that the fluctuation of the vertical load in the thrust direction becomes severe during the air-water mixing operation.

FIG. 3 is a cross-sectional view showing an entire conventional vertical shaft pump 3 that performs the preliminary 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 includes a discharge elbow 30 installed and fixed on the pump installation floor, a casing 29 connected to the lower end of the discharge elbow 30, and a lower end of the casing 29 and an impeller 22. And a suction bell 27 that is connected to the lower end of the discharge bowl 28 and sucks water.

A single rotating shaft 10 formed by connecting two upper and lower shafts to each other by a shaft coupling 26 is provided at substantially the center in the radial direction of the casing 29, the discharge bowl 28, and the suction bell 27 of the vertical shaft pump 3. Has been placed. The rotary shaft 10 is supported by an upper slide bearing device 32 fixed to the casing 29 via a support member, and a lower slide bearing device 33 fixed to the discharge bowl 28 via a support member. An impeller 22 for sucking water into the vertical shaft pump 3 is connected to one end side (suction bell 27 side) of the rotary shaft 10. The other end of the rotating shaft 10 extends to the outside of the vertical shaft pump 3 through a hole provided in the discharge elbow 30 and is connected to a driving machine such as an engine or a motor that rotates the impeller 22.

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

The drive will be installed on land so that maintenance and inspection can be performed easily. The rotation of the driving machine is transmitted to the rotary shaft 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.

FIG. 4 is an enlarged view of the sliding bearing device used in the sliding bearing

devices

32 and 33 shown in FIG. FIG. 5 is a perspective view of a plain bearing installed in the plain bearing device shown in FIG. As shown in FIG. 4, the rotating shaft 10 has a sleeve 11 made of stainless steel, ceramics, sintered metal, or surface-modified metal on the outer periphery thereof. A slide bearing 1 made of a hollow cylindrical resin material, ceramics, sintered metal, or surface-modified metal is provided on the outer peripheral side of the sleeve 11. 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. As shown in FIG. 5, the plain bearing 1 has a hollow cylindrical shape, the inner peripheral surface 1 a faces the outer peripheral surface of the sleeve 11, and the outer peripheral surface 1 b is fitted in the bearing case 12.

FIG. 6 is a schematic diagram showing a connection state with a drive unit such as a motor in the upper part of the vertical shaft pump 3 shown in FIG. The rotary shaft 10 that is shaft-sealed by the shaft seal 34 and extends upward from the discharge elbow 30 in the upper portion of the vertical shaft pump 3 is connected to the rotary shaft 56 of the prime mover 50 by the coupling 51 at the end. The prime mover 50 is fixed on a prime mover stand 52 that supports the prime mover 50. The prime mover base 52 is fixed to the base 53. The rotary shaft 10 is provided with a rolling bearing 55 that receives a thrust force. The rolling bearing 55 is accommodated in the bearing housing 54. The bearing housing 54 is fixed to the gantry 53. The bearing housing 54 is filled with lubricating oil necessary for lubricating the rolling bearing 55.

By the way, in recent years, pumping stations have been placed deeper underground, and advance standby pumps are also becoming longer shafts accordingly. The longer the rotating shaft is, the more the portion of the rotating shaft is swung around. In order to suppress the swinging of the shaft, it has become necessary to arrange more slide bearings at appropriate positions along the rotating shaft.

However, this may cause new technical problems. FIG. 7 is a schematic cross-sectional view showing the state of the rotary shaft 10, the sleeve 11, and the slide bearing 1 in a pump in which the slide bearing

devices

32, 33 are arranged in a portion where the shaft swings heavily. In the dry operation, when the slide bearing 1 of the slide bearing

devices

32 and 33 and the sleeve 11 attached to the rotary shaft 10 slide, the frictional force at the contact portion (portion indicated by hatching) increases and wears. The frictional heat generated at the same time is increased. Therefore, there is a concern about damage to the slide bearing 1 and the sleeve 11.

On the other hand, the rotary shaft and the slide bearing have been conventionally surrounded by a protective tube so that the pump can be operated with the sliding surface of the slide bearing existing in water even during dry operation. Thus, it has been proposed to allow fresh water to flow into the protective tube, or to replace all the sliding bearing devices with water that accumulates in the sliding bearing devices so that the sliding surface exists in the water. . However, when a protective tube is used, an incidental facility for supplying water to the protective tube is required, and maintenance of the slide bearing device is difficult. In addition, since the stand-by pump is also becoming longer, it is necessary to increase the size of the water pump that supplies water to the protective pipe, and to increase the thickness of the pipe wall to strengthen the pressure resistance of the protective pipe. Becomes expensive. In addition, when replacing all plain bearing devices with those in which water is stored in the plain bearing device so that the sliding surface exists in the water, the structure of such a plain bearing device is complicated in the first place. However, there is a problem that it becomes expensive and maintenance is difficult. In addition, since the long shaft is being advanced, the number of the plain bearing devices is increased, and the cost burden and the maintenance complexity are doubled. Moreover, since such a sliding bearing device becomes relatively large in size, there is a problem that it becomes resistance to water flow and lowers pump performance.

In the first place, it is only necessary to appropriately reduce the rotation of the rotating shaft as a whole, but until now, there have been many local measures such as measures for bearings with a large bearing load. It was.

Therefore, the inventors have a sliding bearing device that has a mechanism that, when the rotating shaft slides in dry operation, generates a couple of frictional forces that are opposite to each other to cancel the frictional force and suppress the swinging of the rotating shaft. (See Patent Document 1).

In this plain bearing device, the canceling force depends on the magnitude of the deflection width (radial deflection width) perpendicular to the axial direction of the rotating shaft. That is, when this slide bearing device is arranged in a place (antinode) where the swing of the rotating shaft is large, the effect of suppressing the swing is great, but this slide bearing device is installed in a place (node) where the swing of the rotating shaft is small. If this is arranged, this effect is difficult to obtain.

However, it is difficult to know in advance exactly which part of the rotary shaft of the vertical pump that extends vertically is the maximum (antinode) or minimum (node), and the axial direction of the rotary shaft There is a possibility that the slide bearing device may be mistakenly arranged at a position of a node having a small vertical swing width. When this sliding bearing device is arranged at the position of the node, it is difficult to suppress the swing of the rotating shaft. Also, once the plain bearing is attached to the vertical shaft pump, its position cannot be modified. Moreover, since the slide bearing device of the present invention is large in size, it is necessary to arrange the plain bearing device so as not to hinder the pump performance and the fluid flow, and the arrangement position is limited. Therefore, depending on the position where it can be arranged, there is a case where a sufficient reverse couple cannot be exhibited.

International Publication No. 2015/012350 Japanese Patent Laying-Open No. 2015-222117 JP-A-6-94035 JP 2000-130390 A JP 2001-289191 A

The present invention has been made in view of the above problems, and is more likely to occur when the rotating shaft becomes longer when operating in a state where the water surface does not reach the pump casing of the vertical shaft pump. An object of the present invention is to provide a vertical shaft pump that appropriately reduces the swaying of a rotating shaft as a whole as a whole.

According to an aspect of the present invention, there is provided a vertical shaft pump including a rotary shaft, a pump casing that houses at least a part of the rotary shaft, and an impeller attached to the rotary shaft. The vertical shaft pump is disposed in the pump casing and supports the rotary shaft, and the second plain bearing device is disposed outside the pump casing and supports the rotary shaft. The first slide bearing device is used in a state where the sliding surface is in an air atmosphere during air operation, and the second slide bearing device is always used in a state where the sliding surface is in a liquid atmosphere. The

In one embodiment of the present invention, the second plain bearing device is configured to support the rotating shaft above the pump casing.

In one embodiment of the present invention, the second sliding bearing device includes a radial sliding bearing that receives a radial force of the rotating shaft and a thrust sliding bearing that receives a thrust force of the rotating shaft.

In one embodiment of the present invention, the second plain bearing device includes a perfect circle bearing or a multi-arc bearing.

In one embodiment of the present invention, the second plain bearing device includes a bearing housing that holds the liquid so that the sliding surface contacts the liquid.

In one embodiment of the present invention, the pump casing includes an air pipe upstream of the impeller.

According to the present invention, the liquid film effect in the bearing generated on the sliding surface of the sliding bearing device that is always used in an underwater atmosphere against the frictional force generated on the sliding surface of the sliding bearing device used in an atmospheric atmosphere. By generating a force in the direction opposite to the above frictional force, the swinging of the rotary shaft of the vertical pump can be suppressed as a whole by utilizing the damping effect.

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 conventional vertical shaft pump which performs the prior | preceding standby operation shown in FIG. FIG. 4 is an enlarged view of a sliding bearing device used in the sliding bearing device shown in FIG. 3. It is a perspective view of the slide bearing installed in the slide bearing apparatus shown in FIG. It is the schematic diagram which showed the connection condition with drive machines, such as a motor, in the upper part of the vertical shaft pump shown in FIG. It is typical sectional drawing which shows the state of the rotating shaft, sleeve, and slide bearing in the pump which has arrange | positioned the slide bearing apparatus in the part where the shaft runout becomes intense. It is a longitudinal cross-sectional view of the vertical shaft pump which concerns on this embodiment. It is the schematic diagram which showed the connection condition of the rotating shaft of the vertical shaft pump which concerns on this embodiment, and the rotating shaft of a motor | power_engine. It is a longitudinal cross-sectional view of the plain bearing apparatus with which the motor | power_engine mount part outside the casing which concerns on this embodiment was equipped. It is sectional drawing which shows typically the force which acts on the sliding part of the sliding bearing apparatus operate | moved in air | atmosphere atmosphere without liquid lubrication on a sliding surface at the time of air | atmosphere (dry) driving | operation. The figure which shows typically the force which acts on the sliding part of the radial slide bearing accommodated in the bearing housing 3 and used in the state which has a sliding surface in the liquid atmosphere immersed in liquids, such as lubricating oil and water. It is. It is a figure explaining the kind of typical bearing by the cross-sectional shape cut | disconnected in the radial direction of the slide bearing. It is a figure explaining the kind of typical bearing by the cross-sectional shape cut | disconnected in the radial direction of the slide bearing. It is a figure explaining the kind of typical bearing by the cross-sectional shape cut | disconnected in the radial direction of the slide bearing. It is a figure explaining the kind of typical bearing by the cross-sectional shape cut | disconnected in the radial direction of the slide bearing.

Hereinafter, embodiments of a vertical shaft pump and a plain bearing device used therefor according to the present invention will be described with reference to FIGS. 8 to 13. 8 to 13, the same or corresponding components are denoted by the same reference numerals, and redundant description is omitted. In the present specification, “upper part” and “lower part” are described as meaning the downstream side (“discharge” side in the figure) and the upstream side (“suction” side in the figure) of the liquid transferred by the vertical shaft pump, respectively. To do.

FIG. 8 is a longitudinal sectional view of the vertical shaft pump 3 according to the present embodiment. The vertical shaft pump 3 is a pump that may operate a rotating shaft in a state where there is no pumping target water in the pump casing. Some vertical shaft pumps perform a management operation in such a state, and others perform an aerial operation in a preceding standby operation. FIG. 8 illustrates a vertical shaft pump that performs a preliminary standby operation. Note that the management operation is an operation to check whether the pump can be operated normally when the pump is stopped due to the rainy season, and the inside of the pump casing is not dry. It is an operation performed in a state. The operation time may be several ten minutes to several tens of minutes.

As shown in FIG. 8, the vertical shaft pump 3 includes a discharge elbow 30 installed and fixed on the pump installation floor, a casing 29 connected to the lower end of the discharge elbow 30, and a lower end of the casing 29 and an impeller 22. A discharge bowl 28 that stores therein (corresponding to an example of an impeller) and a suction bell 27 that is connected to the lower end of the discharge bowl 28 and sucks water are provided. The lower end of the suction bell 27 to the discharge end of the discharge elbow 30 is called a pump casing.

A through hole is provided in a side surface portion of the suction bell 27 on the inlet side of the impeller 22, and an air pipe 6 having an opening in contact with outside air is attached to the through hole. Thereby, this vertical shaft pump 3 changes the supply amount of the air supplied in the vertical shaft pump 3 through a through-hole according to a water level, and the amount of drainage of the vertical shaft pump 3 is controlled.

Rotating shaft 10 is arranged at a substantially central portion in the radial direction of casing 29, discharge bowl 28, and suction bell 27 of vertical shaft pump 3. An impeller 22 for sucking water into the pump is connected to one end side (suction bell 27 side) of the rotating shaft 10.

The rotary shaft 10 is a slide bearing device 32 fixed to the casing 29 via a support member at an appropriate position in the axial direction, and a slide bearing device fixed to the inner cylinder of the discharge bowl 28 via the support member. 33 and / or in the case of the rotating shaft 10 penetrating the impeller 22, the lower end portion of the rotating shaft 10 is supported by a plain bearing device 33 fixed to the casing 29 via a support member. The sliding

bearing devices

32 and 33 may be sliding bearing devices that are used in a state where the sliding surface is in an atmospheric atmosphere during atmospheric operation. The sliding bearing device used in a state where the sliding surface is in an atmospheric atmosphere during the atmospheric operation is the sliding bearing device shown in FIGS. 4 and 5.

That is, as shown in FIG. 4, this plain bearing device has a sleeve 11 made of stainless steel, ceramics, sintered metal, surface-modified metal, or the like on the outer periphery of the rotating shaft 10. A slide bearing 1 made of a hollow cylindrical resin material, ceramics, sintered metal, or surface-modified metal is provided on the outer peripheral side of the sleeve 11. 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 plain bearing 1 is fixed to a support member 13 connected to a pump casing 29 and the like through a collar portion 12a by a bearing case 12 made of metal or resin. As shown in FIG. 5, the plain bearing 1 has a hollow cylindrical shape, the inner peripheral surface 1 a faces the outer peripheral surface of the sleeve 11, and the outer peripheral surface 1 b is fitted in the bearing case 12. One or more of the slide bearing device 33 and the slide bearing device 32 are arranged at one place, and a plurality of the slide bearing devices are combined.

The upper end side of the rotary shaft 10 extends to the outside of the vertical shaft pump 3 through a hole provided in the discharge elbow 30 and is connected to a drive machine such as an engine or a motor that rotates the impeller 22. A shaft seal 34 such as a floating seal, a gland packing, or a mechanical seal is provided between the rotary shaft 10 and a hole provided in the discharge elbow 30, and the water handled by the vertical pump 3 by the shaft seal 34 is supplied to the vertical pump. 3 is prevented from flowing out.

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

FIG. 9 is a schematic diagram showing a connection state between the rotary shaft 10 of the vertical shaft pump 3 and the rotary shaft 56 of the prime mover 50 according to the present embodiment. The rotary shaft 10 that is shaft-sealed by the shaft seal 34 and extends upward from the discharge elbow 30 in the upper portion of the vertical shaft pump 3 is connected to the rotary shaft 56 of the prime mover 50 by the coupling 51 at the end. The prime mover 50 is fixed on a prime mover stand 52 that supports the prime mover 50. A slide bearing device 60 having a radial slide bearing 61 (see FIG. 10) that receives the radial force of the rotary shaft 10 and a thrust slide bearing 62 (see FIG. 10) that receives the thrust force is housed and supported in a bearing housing 63. It is fixed to the gantry 53 via a bearing housing 63.

Incidentally, the upper part of the rotary shaft 10 of the vertical shaft is relatively firmly restrained by the structure described above. That is, the sliding bearing device 60 of the rotating shaft 10 and the bearing housing 63 that supports the sliding bearing device 60 are firmly fixed to the pedestal 53 having high rigidity that supports them. Therefore, the shake of the rotating shaft 10 is restrained by them. However, below the portion of the rotating shaft 10 supported by the plain bearing device 60, the distance to the impeller 22 is long. Although the degree of swinging varies depending on the position in the height direction, the

plain bearing devices

32 and 33 are provided to support the rotary shaft 10 so as to suppress this swinging.

With regard to the arrangement of the sliding bearing device 32, the design of the rotating shaft 10 can be determined based on conditions such as the thickness, length, rotational speed, weight of the impeller, and the number of impellers based on experience or expedient calculation in the design stage. A position with a large run-out is determined, and based on this, a certain number of positions in the axial direction is determined. However, the arrangement position of the sliding bearing device 32 predicted as a position where the swing of the rotating shaft 10 is large may deviate from a position where the actual swing is large. Further, the arrangement position of the plain bearing device 32 cannot be corrected after the vertical shaft pump 3 is assembled.

In particular, as the rotating shaft 10 becomes longer, a portion with a large swing around the rotating shaft 10 is likely to occur at a plurality of locations. In order to suppress this, it is necessary to arrange more sliding bearing devices 32 along the axial direction of the rotary shaft 10. However, as a result, the number of cases where the arrangement position of the sliding bearing device 32 deviates from the position where the actual rotation of the rotary shaft 10 is large is increasing, and the size of the deviation is also increasing. That is, a part of the plurality of plain bearing devices is disposed at a so-called “node” position where the swing of the rotating shaft 10 is extremely small.

By the way, in the dry operation, when the slide bearing 1 in the

slide bearing devices

32 and 33 and the sleeve 11 attached to the rotary shaft 10 slide, the frictional force at the contact portion increases, and the generated frictional heat increases. Become. Therefore, there is a concern about damage to the slide bearing 1 and the sleeve 11.

In particular, the sliding

bearing devices

32 and 33 provided in a place where the swivel of the rotating shaft 10 has a large bearing load causes local wear and high temperature of the sleeve 11 attached to the rotating shaft 10 of the other party to slide. It becomes easy and the vibration and bearing load by interference with the rotary body (rotary shaft 10 and sleeve 11) and fixed body (slide bearing 1) of the vertical shaft pump 3 increase.

Therefore, the vertical shaft pump 3 according to this embodiment includes a radial plain bearing 61 as a bearing device that receives the radial force of the rotary shaft 10 in the prime mover mount 52 portion outside the casing 29. The sliding surface of the radial plain bearing 61 is accommodated in the bearing housing 63 and immersed in a liquid such as lubricating oil or water.

FIG. 10 is a longitudinal sectional view of the plain bearing device 60 provided in the prime mover base 52 portion outside the casing 29 according to the present embodiment. As shown in FIG. 10, the plain bearing device 60 has a bearing housing 63. The bearing housing 63 includes an inner cylinder 63a which is a substantially cylindrical wall having a diameter slightly larger than the diameter of the rotary shaft 10, an outer cylinder 63b having a substantially cylindrical wall having a diameter larger than the inner cylinder 63a, and wall surfaces of the inner cylinder 63a and the outer cylinder 63b. A bottom plate 63d that connects the lower portions of the inner cylinder 63a and a top plate 63c that connects the upper portions of the wall surfaces of the inner cylinder 63a and the outer cylinder 63b. Thus, the bearing housing 63 forms a tank that can receive lubricating oil, water, and the like. Although each member can be disassembled, they are joined together in a watertight manner in the assembled state, and even if liquid is injected into the formed bearing housing 63, it does not leak outside.

On the outer periphery of the rotary shaft 10, a sliding surface that transmits a sliding load in the radial direction to the radial sliding bearing 61 and a sliding that transmits the sliding load of the upper and lower thrusts to the upper thrust sliding bearing 62a and the lower thrust sliding bearing 62b. A rolling element 65 having a surface is fixed. As the rotary shaft 10 rotates, the rolling element 65 rotates. At least the sliding surface of the rolling element 65 is made of stainless steel, ceramics, sintered metal, or surface-modified metal.

The rolling element 65 has a sliding surface for transmitting a sliding load in the radial direction on a part of the outer peripheral surface thereof, and is opposed to the sliding surface by a hollow cylindrical resin material, ceramic, sintered metal, or A radial slide bearing 61 made of a surface-modified metal is provided. The radial sliding bearing 61 slides on the cylindrical outer peripheral surface of the rolling element 65. The sliding surface of the rolling element 65 and the sliding surface of the radial slide bearing 61 are arranged so as to face each other and slide through a very narrow clearance. The radial slide bearing 61 is supported and fixed to the bearing housing 63 by a bearing support member 66 made of metal or resin and a bottom plate 63d. The bearing support member 66 is fixed in the bearing housing 63. In addition, a slight gap is formed between the top plate 63c and the rotating body 65 and the rotating body such as the rotating shaft 10, or is almost sealed by a sliding seal member such as a lip seal.

Rotating shaft 10 extends inside inner cylinder 63a. The rolling elements 65 are arranged so as to cover the inner cylinder 63a from the outside. Moreover, the rolling element 65 has a disk-shaped portion 65a extending in the outer peripheral direction from the lower end thereof. The disk-like portion 65a has sliding surfaces facing the upper thrust sliding bearing 62a and the lower thrust sliding bearing 62b on part of the upper and lower surfaces thereof.

The upper thrust slide bearing 62a and the lower thrust slide bearing 62b are made of a hollow disk-shaped (doughnut-shaped) resin material, ceramics, sintered metal, or surface-modified metal, and slide with the rolling element 65. The respective sliding surfaces of the rolling elements 65 and the sliding surfaces of the upper thrust sliding bearing 62a and the lower thrust sliding bearing 62b are arranged to face each other and slide with a very narrow clearance. The upper thrust slide bearing 62a and the lower thrust slide bearing 62b are supported and fixed to the bearing housing 63 by a bearing support member 66 and a bottom plate 63d made of metal or resin. When the vertical shaft pump 3 performs the air / water mixing operation in the preceding standby operation, the variation in the load in the thrust direction becomes severe. However, in this embodiment, since the upper thrust slide bearing 62a and the lower thrust slide bearing 62b are provided, the rotational motion can be stably continued even if the load fluctuation in the thrust vertical direction of the rotating shaft 10 occurs.

The upper end portion of the inner cylinder 63a of the bearing housing 63 extends to a position higher than the sliding surfaces of the rolling element 65, the radial sliding bearing 61, the upper thrust sliding bearing 62a, and the lower thrust sliding bearing 62b. A gap passage 71 is formed in an annular shape between the inner cylinder 63a, the rolling element 65, and the rotating shaft 10 so that the upper end and side surfaces of the inner cylinder 63a do not interfere with the rolling element 65 and the rotating shaft 10. .

According to the slide bearing device 60 of the present embodiment, the liquid level of water or oil or the like is injected into the space in the bearing housing 63 to the height FL of the upper end of the inner cylinder 63a, and the vertical shaft pump 3 is operated. It becomes possible. When the liquid is injected beyond the FL, the liquid overflows the upper end of the inner cylinder 63a. Therefore, it is preferable to monitor the liquid level with a level meter or the like so as not to overflow. Since the upper end of the inner cylinder 63a extends to a position higher than the upper ends of the sliding portions of the rolling element 65, radial sliding bearing 61, upper thrust sliding bearing 62a, and lower thrust sliding bearing 62b, these sliding portions Can be located in the liquid.

In addition, when the bearing housing 63 can be disassembled and assembled, each slide bearing in the bearing housing 63 can be replaced. Further, as shown in FIG. 10, a liquid supply pipe 69 and a supply valve 69a are provided in the upper part of the bearing housing 63, and a liquid discharge pipe 68 and a discharge valve 68a are provided in the lower part. It may be easy to inject and discharge. Thereby, the inside of the bearing housing 63 can be cleaned.

In the vertical shaft pump 3 according to the present embodiment, when the rotating shaft 10 and the rolling element 65 are rotated in a state where a predetermined amount of liquid such as lubricating oil or water is injected into the bearing housing 63, the liquid is accompanied with the rotation. Rotate and get centrifugal force. However, since the outer peripheral portion of the bearing housing 63 is assembled in a watertight manner by the outer cylinder 63b and the top plate 63c, scattering to the outside due to the centrifugal force of the liquid can be prevented. The liquid level rises on the wall surface of the bearing housing 63 due to the pressure of the centrifugal force. However, the top plate 63c changes the direction of the liquid toward the rotating shaft 10, and the top plate 63c is opposed to the rotating body with a slight clearance, or the space between the top plate 63c and the rotating body is almost sealed. As a result, the liquid is prevented from jumping over the top plate 63c. Accordingly, the sliding portions of the radial sliding bearing 61, the upper thrust sliding bearing 62a, and the lower thrust sliding bearing 62b are in a state of being submerged in the liquid when the rotary shaft 10 rotates.

Here, the sliding

bearing devices

32 and 33 in the pump casing used in a state where the sliding surface is in an air atmosphere during the air (dry) operation, and the radial slide used in a state where the sliding surface is in a liquid atmosphere. The phenomenon that occurs with the bearing 61 will be described.

FIG. 11 is a cross-sectional view schematically showing a force acting on a sliding portion of a slide bearing device operated in an air atmosphere without liquid lubrication on a sliding surface during an air (dry) operation. FIG. 11 shows a cross section perpendicular to the axial direction of the rotating shaft 10. Here, the rotation side is the rotation shaft 10 and the sleeve 11 fitted thereto. On the other hand, the fixed side is a plain bearing 1 and a bearing case 12 that supports it. In FIG. 11, the dimension of the clearance between the sleeve 11 and the slide bearing 1 is shown enlarged for convenience.

When the rotating shaft 10 rotates, the sleeve 11 fixed to the rotating shaft 10 rotates. When this sliding bearing device is used in an air atmosphere, when the outer peripheral surface of the sleeve 11 comes into contact with the sliding bearing 1 at point A due to the swinging of the rotating shaft 10, the bearing reaction force F _AN is applied to the rotating shaft 10. appear. By this bearing reaction force _FAN , a frictional force _FAF is generated in a direction opposite to the rotational direction of the rotary shaft 10, and this frictional force _FAF causes a whirling vibration in the direction opposite to the rotational direction on the rotary shaft 10. Stabilization power.

It should be noted here that the magnitude of the frictional force F _AF that is the destabilizing force is the swing width perpendicular to the axial direction of the rotating shaft 10 (that is, the swing width in the radial direction of the rotating shaft 10). Depends on size. That is, the magnitude of the frictional force F _AF is relatively sensitive to whether the swing of the rotating shaft 10 is belly or node.

FIG. 12 shows the force acting on the sliding portion of the radial sliding bearing 61 housed in the bearing housing 63 and used in a state where the sliding surface is in a liquid atmosphere immersed in a liquid such as lubricating oil or water. It is a figure shown typically. FIG. 12 shows a cross section perpendicular to the axial direction of the rotating shaft 10. In the radial plain bearing 61, the rotating side is the rotating shaft 10 and the rolling element 65 connected thereto. On the other hand, the fixed side is a radial slide bearing 61 and a bearing support member 66 that supports it.

When the rotating shaft 10 rotates, the rolling element 65 fixed to the rotating shaft 10 rotates. Since the sliding surface is in a liquid atmosphere such as lubricating oil or water, a liquid film is formed between the rolling element 65 and the radial slide bearing 61. At this time, the circumferential direction of the pressure nonuniformity caused by rotation, which element 65 is in the liquid film, so that the radial fluid forces F _AR and the circumferential fluid force F _AT occurs the rolling element 65. The effect of this phenomenon called the liquid film effect bearings, the force of the circumferential fluid force F _AT is the reverse rotation direction (reverse direction) to the frictional force F _AF generated by dry operation described in connection with FIG. 11 It is.

It should be noted that, dependent of circumferential fluid forces F _AT to the magnitude of the vertical deflection width in the axial direction of the rotary shaft 10 is smaller than the frictional force F _AF during dry operation in FIG. 11 That is. That is, the circumferential fluid force F _AT is runout of the rotating shaft 10 is not whether a clause or a belly, but rather affects the magnitude of the rotational speed.

By the way, the liquid film effect in the bearing also depends on the cross-sectional shape of the radial slide bearing 61 cut in the radial direction. FIG. 13A to FIG. 13D are diagrams for explaining typical types of bearings having a cross-sectional shape cut in the radial direction of the radial slide bearing 61. FIG. 13A shows a perfect circle bearing, FIGS. 13B and 13C show a multi-arc bearing, and FIG. 13D shows a tilting pad bearing. Specifically, FIG. 13B shows a two-arc bearing, and FIG. 13C shows an offset bearing. In FIG. 13A to FIG. 13D, the hatched portion represents the rotating shaft 10.

13A has a groove 41 substantially in the axial direction on the sliding surface, and quickly supplies water and lubricating oil in the axial direction of the slide bearing 2 through the groove 41. Note that the perfect circle bearing shown in FIG. 13A may not include the groove 41. The radius of the sliding surface of the portion where the groove 41 of the perfect circle bearing in FIG. 13A is not formed is r and the center is O. Of these three types of bearings, a perfect circle bearing is most likely to have a liquid film effect in the bearing, and therefore is also likely to generate a force.

The two-arc bearing shown in FIG. 13B also has a groove 41 along the axial direction on the sliding surface in the same manner as the perfect circle bearing in FIG. 13A. In the multi-arc bearing shown in FIGS. 13B and 13C, the radius of the slide bearing surface on which the rotary shaft 10 slides is basically r, but this slide bearing surface is composed of a plurality of arcs with different centers. It is configured. The two arc bearing shown in FIG. 13B and the offset bearing shown in FIG. 13C have centers O ₁ and O ₂ with respect to the two arcs. A multi-arc bearing having two or more arcs can also be constructed. Multi-arc bearings are not as good as perfect circle bearings among these three types, but they can still produce a liquid film effect in the bearings.

The tilting pad bearing shown in FIG. 13D has a plurality of plain bearing surfaces called pads 43 that can tilt around the rotating shaft 10 as a fulcrum, and surrounds the rotating shaft 10. The tilting pad bearing does not produce a liquid film effect in the bearing.

Conventionally, if the liquid film effect is caused by sliding the rotary shaft 10 in the liquid on the sliding surface of the slide bearing, an unstable force is applied to the rotary shaft 10 of the vertical shaft pump 3, so that the liquid film effect does not occur. In many cases, tilting pad bearings are used. However, in the present embodiment, the radial slide bearing 61 used in the liquid shown in FIG. 10 is adopted, and the rotary shaft 10 is attached to the rotary shaft 10 by the slide bearing 1 having a dry sliding surface at the time of the dry standby operation. The force opposite to the generated frictional force F _AF is generated by the liquid film effect in the radial slide bearing 61 whose sliding surface is always in the liquid. For this reason, in this embodiment, a multi-arc bearing, more preferably a perfect circle bearing is used.

As can be understood from the above-described principle, the vertical shaft pump 3 of the present embodiment is used in a state in which the sliding

bearing devices

32 and 33 in the casing 29 are in a state where the sliding surfaces are in an atmospheric atmosphere during atmospheric operation. A sliding bearing device can be obtained. On the other hand, the sliding bearing device 60 that receives the radial force of the rotary shaft 10 is used in a state in which the sliding surface is immersed in a liquid such as lubricating oil or water at the prime mover base 52 portion outside the casing 29. A sliding bearing device can be obtained. As a result, during the atmospheric operation of the vertical shaft pump 3, the frictional force shown in FIG. 11 and the circumferential fluid force shown in FIG. 12 are generated simultaneously. Therefore, the force to destabilize the rotary shaft 10 (the frictional force F _AF) is circumferentially fluid force F _AT, whirling of the rotary shaft 10 is suppressed because the offset in opposite directions. Therefore, even when the sliding portion of the lowest slide bearing of the plurality of

slide bearing devices

32 and 33 in the pump casing is not immersed in water such as pumped water, a pump that can be stably operated without problems is provided. can do.

If the canceling force depends on the magnitude of the swing width perpendicular to the axial direction of the rotating shaft 10, that is, the canceling force is generated by generating a couple of frictional forces opposite to each other as disclosed in Patent Document 1 and the like. However, when using a sliding bearing device or the like having a mechanism for suppressing the swinging of the rotary shaft 10, the sliding bearing device should be arranged so that a canceling force is applied to a portion where the swing width perpendicular to the axial direction is maximum. is there. However, as described above, it is difficult to accurately determine in advance which portion of the rotation shaft 10 has the maximum (antinode) or minimum (node) swing width, and the rotation shaft 10 There is a possibility that it is arranged at the position of a node having no runout width perpendicular to the axial direction. Once the plain bearing device is arranged at the node position, it becomes difficult to stop the rotation of the rotating shaft, and the position cannot be changed later.

However, in the vertical shaft pump 3 according to the present embodiment, by providing the slide bearing device 60 that is used in a state where the sliding surface is immersed in the liquid, the canceling couple acting on the rotary shaft 10 is used as the circumferential fluid force. Yes. Unlike the generation of the canceling force due to the frictional force, this canceling force does not depend very much on the swing width perpendicular to the axial direction of the rotating shaft 10, but rather depends on the rotational speed, so that the installation position is rotated. Regardless of whether the shaft is an antinode or a node, a suitable canceling force can be generated regardless of the location of the rotary shaft 10 where the sliding bearing device 60 is disposed. And the cancellation effect is large according to the high rotational speed of the rotating shaft 10 or high peripheral speed.

Therefore, according to the present embodiment, since the swinging of the rotating shaft 10 is suppressed, even if a slide bearing is disposed on the abdomen of the rotating shaft 10, the sliding portion may be locally worn or damaged due to high temperatures. The fear is gone.

Further, in the vertical shaft pump 3 according to the present embodiment, a plurality of plain bearing devices conventionally provided in the casing of the vertical shaft pump are used as the sliding

bearing devices

32 and 33 that are used in a state where the sliding portion is in the atmosphere. Since it can be used, the resistance and loss of the fluid inside the casing 29 are not increased as compared with the conventional vertical pump. Further, the vertical shaft pump 3 of the present embodiment includes a sliding bearing device 60 that receives the radial force of the rotating shaft 10 in the prime mover base 52 portion outside the casing 29, and the sliding surface of the sliding bearing device 60 has a lubricating oil. Used in a state immersed in a liquid such as water. For this reason, the sliding bearing device 60 does not require an incidental facility such as a facility for supplying water to the protective tube, and is easy to maintain, as compared with the case where a conventional protective tube is used. Further, since the vertical shaft pump 3 according to the present embodiment also uses the

slide bearing devices

32 and 33 whose sliding surfaces are dry during dry operation, all the slide bearing devices are slid with water stored inside. Compared to the case where the surface is replaced with a plain bearing device in which the surface is present in water, the cost can be reduced, maintenance can be easily performed, and the influence on the pump performance can be reduced.

As described above, the embodiment of the present invention has been described mainly using the vertical shaft pump that performs the preliminary standby operation as an example, but the vertical shaft pump 3 rotates the rotating shaft in a state where there is no water to be pumped in the pump casing. A pump that may be operated in such a state, and a pump that performs a management operation in such a state is also included. The above-described embodiments of the present invention are intended to facilitate understanding of the present invention, and do not limit the present invention. The present invention can be changed and improved without departing from the gist thereof, and the present invention includes the equivalents thereof. In addition, any combination or omission of each component described in the claims and the specification is possible within a range where at least a part of the above-described problems can be solved or a range where at least a part of the effect can be achieved. is there.

DESCRIPTION OF SYMBOLS 3 ... Vertical shaft pump 6 ... Air pipe 10 ... Rotary shaft 22 ... Impeller 29 ... Casing 32 ... Slide bearing device 33 ... Slide bearing device 60 ... Slide bearing device 61 ... Radial slide bearing 62 ... Thrust slide bearing 62a ... Upper thrust slide bearing 62b ... Lower thrust plain bearing 63 ... Bearing housing 65 ... Rolling element

Claims

A vertical shaft pump comprising: a rotary shaft; a pump casing that houses at least a part of the rotary shaft; and an impeller attached to the rotary shaft,
A first plain bearing device disposed in the pump casing and supporting the rotating shaft;
A second plain bearing device disposed outside the pump casing and supporting the rotating shaft,
The first plain bearing device is used in a state where the sliding surface is in an air atmosphere during air operation,
The second plain bearing device is a vertical shaft pump that is always used in a state where the sliding surface is in a liquid atmosphere.
The vertical shaft pump according to claim 1,
The second plain bearing device is a vertical shaft pump configured to support the rotating shaft above the pump casing.
In the vertical shaft pump according to claim 1 or 2,
The second sliding bearing device includes a radial sliding bearing that receives a radial force of the rotating shaft and a thrust sliding bearing that receives a thrust force of the rotating shaft.
In the vertical shaft pump according to any one of claims 1 to 3,
The second plain bearing device is a vertical shaft pump having a perfect circle bearing or a multi-arc bearing.
In the vertical shaft pump according to claims 1 to 4,
The second sliding bearing device is a vertical shaft pump having a bearing housing that holds the liquid so that the sliding surface contacts the liquid.
In the vertical shaft pump according to any one of claims 1 to 5,
The pump casing is a vertical pump including an air pipe on the upstream side of the impeller.