JPH0733567Y2 - Shaft seal structure for pump drive submersible motor - Google Patents

Description

[Detailed Description of the Invention] [Industrial field of application] The present invention is used for pumping, especially for pumping up pumped water containing a lot of highly corrosive substances such as seawater, Braxish water, and high chlorine ion concentration water. The present invention relates to a shaft seal structure for a pump driving submersible electric motor that drives a pump.

[Prior art]

Conventionally, as this type of underwater electric motor, for example, there is an underwater electric motor for driving a fresh water pump having a structure shown in FIG.

The submersible motor shown in FIG. 3 has a frame 51 that contacts the pump liquid.
A stator core 52 formed by laminating silicon steel plates is disposed inside, and a rotor core 54 formed by laminating silicon steel plates is also arranged at the center of the stator core 52. A main shaft 55 penetrates through the center of the rotor core 54, and both ends of the main shaft 55 are rotatably supported by a radial bearing metal 56 fixed to a lower bracket 58 and a radial bearing metal 57 fixed to an upper bracket 59. It is supported. A shaft seal 60 such as an oil seal is arranged on the radial bearing metal 57, a seal cover 61 is arranged on the shaft seal 60, and a sand slinger 62 is arranged on the seal cover 61.

A filling liquid Q is filled inside the frame 51. Reference numeral 53 is a stator coil mounted on the stator core 52, 63 is a thrust bearing device, and 64 is an automatic hydraulic pressure adjusting device for always keeping the hydraulic pressure of the filled liquid Q in the frame 51 constant.

In any of the underwater electric motors having the structure shown in FIG. 3, a pump (not shown) is disposed above the underwater electric motor, and the upper end of the main shaft 55 is connected to the lower end of the pump main shaft and a coupling (not shown). When the submersible electric motor is activated, the rotational force of the main shaft 55 is transmitted to the pump main shaft through the connecting means, and the pumped liquid is lifted up.

[Problems to be solved by the invention]

The underwater electric motor with the above structure can be used for seawater, Brakish water,
When used in a pump that pumps a pumping liquid containing a lot of corrosive substances such as high chlorine ion concentration water, it is in the pumping liquid with strong corrosiveness of the submersible electric motor, so the pumping liquid with strong corrosive property has an electrical conductivity. Highly prone to galvanic corrosion (potential difference corrosion, gap corrosion, etc.), and if this highly corrosive pumping liquid leaks and intrudes from the shaft seal mechanism consisting of the shaft seal 60, etc., it cannot be composed of the corrosion resistant material inside the submersible motor. Parts, eg stator core
52, the rotor core 54, the radial bearing metal 57, etc. rapidly corroded and deteriorated, and the function as an electric motor was lost.

Further, since the upper bracket 59 is also provided with the shaft seal mechanism such as the radial bearing metal 57 and the shaft seal 60, the shaft seal mechanism is not easily replaced, and maintenance is troublesome.

The present invention has been made in view of the above-mentioned problems, and eliminates the above-mentioned problems and does not corrode parts made of a non-corrosion resistant material inside a submersible motor even when used in a highly corrosive pumping liquid. Another object of the present invention is to provide a shaft seal structure for a submersible electric motor for driving a pump, which facilitates maintenance such as replacement of a seal mechanism.

[Means for solving the above problems]

In order to solve the above problems, the present invention provides a shaft sealing structure for a pump driving submersible electric motor, a frame, an end cover provided at an end of the frame, and a bearing bracket arranged on the rotor core side from the end cover and in the frame. And a shaft seal mechanism is arranged in the chamber, the outer periphery of the bearing bracket is fitted into the inner periphery of the frame and is fixed by a fastener attached to the inner periphery of the frame, and the end cover is a bearing. It is configured to be fixed to the frame end by a bolt whose tip is screwed to the bracket.

[Action]

By configuring the shaft seal structure of the pump driving submersible electric motor as described above, the shaft seal mechanism is arranged in the room surrounded by the end cover, the bearing bracket and the frame. Therefore, the shaft seal mechanism is replaced. In this case, the bolt for fixing the end cover is removed and the end cover is removed, so that the shaft seal mechanism can be replaced regardless of the bearing portion, so that the replacement work of the shaft seal mechanism becomes extremely easy. Further, since a large amount of lubricating liquid can be secured in the room in which the shaft seal mechanism is arranged, the sealing effect of the shaft seal mechanism such as the mechanical seal and the oil seal is improved, and the lubrication and cooling are good and the life thereof is extended. .

〔Example〕

 An embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 is a top sectional view of an underwater electric motor having a shaft seal structure according to the present invention. In the underwater electric motor, a stator core 12 formed by laminating silicon steel plates in a frame 11 is arranged, a stator coil 14 is mounted on the stator core 12, and a rotor core 13 is also formed by laminating silicon steel plates in the central portion. Is arranged through. A main shaft 15 is fixed through the center of the rotor core 13, and both ends of the main shaft 15 are fixed to a radial bearing metal (not shown) fixed to a lower bracket (not shown) and an upper bracket 18. It is rotatably supported by a radial bearing metal 17.
The upper bracket 18 is fixed in the frame 11 with a stopper 19. On the upper end of the frame 11, the end cover 20 is fixed to the upper end of the frame 11 by a bolt 26 having a tip portion screwed onto the upper bracket 18.

There is a predetermined gap between the end cover 20 and the upper bracket 18, and the upper bracket 18, the frame 11 and the end cover 18 are provided.
A room 21 surrounded by 20 is formed. A mechanical seal 22 is arranged on the radial bearing metal 17 side in the chamber 21, and an oil seal 23 housed in a seal case 27 is arranged above the mechanical seal 22. A seal cover 24 is provided on the seal case 27, and a sand slinger 25 is provided on the seal cover 24.

In the above structure, the frame 11, which is in contact with the pumped water, the end cover
20, the seal case 27, the upper part of the main shaft 15 and the like are made of corrosion resistant material such as stainless steel. Incidentally, 30 and 31 are packings respectively fitted in the power cable through holes of the end cover 20, and the packings 30 and 31 are formed by interposing packing holding plates 29 and 32 on both sides and tightening the cable nut 33. Airtightness is maintained between the power supply cable 35 and the end cover 20 which penetrate through the holes formed in the central portions of the packings 30 and 31. The power cable 35 is connected to the lead wire of the stator coil 14 by forming a mold portion 34. In addition, a filling liquid Q is filled inside the frame 11,
The enclosed liquid Q also fills a room 21 surrounded by the upper bracket 18, the frame 11 and the end cover 20. The airtightness between the end cover 20 and the seal case 27 is maintained by the O-ring 28.

In the above structure, the main shaft seal is the mechanical seal 22 in the third stage sealing position, the sub shaft seal is the oil seal 23 in the second stage, and the first stage sand slinger 25 is the outermost pumping pump. It is located in contact with. The first stage sand slinger 25 removes foreign matter having a relatively large particle size such as sand contained in the pumping liquid from entering the underwater electric motor.
The oil seal 23 of the third stage removes the invasion of the pumping liquid containing foreign matter of a smaller particle size, and the mechanical seal 22 of the third stage
Completely remove the invasion of the pump. That is, the shaft seal is room 21
The structure is doubled inside to prevent the pumped water from entering the inside of the electric motor. Therefore, the shaft seal structure of a submersible electric motor for driving a pump for pumping a liquid containing a large amount of corrosive substances such as seawater, brachish water, and high chlorine ion concentration water is extremely excellent.

Further, particularly in the shaft seal structure, since the sand slinger 25 and the rubber tongue 23a of the oil seal 23 slide in contact with the main shaft 15, foreign matter such as sand contained in pumped water or the like is difficult to reach the mechanical seal 22. .

Further, since the room 21 surrounded by the upper bracket 18, the frame 11 and the end cover 20 is taken large, a large space can be secured at a position where the sliding surface of the main shaft 15 of the mechanical seal 22 is present, so that a large amount of lubricating liquid As a result, the lubrication and cooling action can be improved, and as a result, the life of the mechanical seal 22 can be extended.

Further, by adopting the above structure, the radial bearing metal
The upper bracket 18 supporting 17 and the seal case 27 supporting the seal portion and the end cover 20 are formed as separate parts, and the upper bracket 18 is attached at a position apart from the end cover 20, that is, the upper end of the frame 11 to form a shaft seal. It becomes possible to accurately hold the main shaft 15 that independently supports the rotation of the rotor core 13 and transmits torque.

Further, since the pumped liquid does not enter through the oil seal 23 and the mechanical seal 22, the upper bracket 18 can be made of a non-corrosion resistant material, and therefore can be manufactured as a common part with the lower bracket by casting, for example.

Further, the end cover 20 is made of a corrosion resistant material as described above,
The shaft seal mechanism including the oil seal 23 and the mechanical seal 22 is formed with a large penetrating portion of the main shaft 15 so that it can be easily inserted into the electric motor. In particular, in the above example, the mechanical seal is used.
Since the 22 and the oil seal 23 are inserted inside, and the seal case 27 etc. for mounting and pressing are separate parts from the end cover 20,
The shaft seal mechanism including the oil seal 23 and the mechanical seal 22 can be easily removed (for maintenance).

After assembling the underwater electric motor body, the power cable 35 is fixed by tightening the packing nuts 29 and 32 on the end cover 20 by tightening the packing nuts 30 and 31 with the cable nut 33. become.

Although the end cover 20 and the seal case 27 are separate components in the above-described embodiment, it is of course possible to form the end cover 20 and the seal case 27 integrally as separate components to form the end cover.

Next, an example of the entire structure of the pump driving submersible electric motor having the shaft seal structure will be described.

FIG. 2 is a sectional view showing the overall structure of a pump driving submersible electric motor having the shaft seal structure. In the figure,
The same reference numerals as those in FIG. 1 indicate the same parts. A lower bracket 40 that supports the radial bearing metal 41 is fixed to the lower portion of the frame 11 with a stopper 42.

A thrust support mechanism 39 including a thrust disk 36 fixed to the lower end of the main shaft 15, a thrust pad 37 slidably contacting the lower surface of the thrust disk 36, a thrust pad support base 38, and the like is disposed below the main shaft 15. Has been done. In addition,
Reference numeral 47 is an adjust screw screwed into a screw hole formed in the lower center of the thrust casing 48.

Further, below the thrust casing 48, an automatic hydraulic pressure adjusting device 49 for keeping the hydraulic pressure of the enclosed liquid Q in the frame 11 always substantially constant is arranged. The automatic fluid pressure adjusting device 49 has a structure in which a diaphragm 43 is housed inside a casing 45, and a flange portion of the diaphragm 43 is fixed to a lower end of the casing 45 via a diaphragm pressing plate 44.

Reference numeral 46 is a diaphragm protection plate fixed to the lower end of the adjusting screw 47.

A pump (not shown) is provided above the submersible motor having the above structure.
The upper end of the main shaft 15 is connected to the lower end of the pump main shaft by a connecting means such as a coupling (not shown), and the rotational force of the main shaft 15 is pumped through the connecting means by activating the underwater electric motor. It is transmitted to the main shaft, and the pumped liquid is lifted up.

[Effect of device]

As described above, according to the present invention, the following excellent effects can be obtained.

Since the shaft seal mechanism is installed in the room surrounded by the frame, end cover and bearing bracket, the shaft seal mechanism can be installed and installed according to the purpose according to the type of foreign matter that prevents intrusion. It is possible to provide a submersible motor for driving a pump, which has a long life and consequently a long life.

Since the end cover can be removed and the seal mechanism can be easily attached and replaced, the shaft seal structure is suitable for a submersible electric motor for driving a pump, which is particularly easy to maintain and requires periodic maintenance.

Since the shaft seal mechanism is installed in the room surrounded by the frame and the end cover with the bearing bracket, a large amount of lubricating liquid can be secured on the seal sliding surface, improving the sealing action, lubrication, and cooling action. The life of the shaft seal mechanism is extended.

Since the shaft seal portion is configured separately from the bearing bracket, it is possible to accurately maintain the position accuracy of the main shaft regardless of the shaft seal, vibration and shaft runout are reduced, and the bearing life is extended.

Compared to the conventional structure in which the bearing bracket and the shaft seal mounting chamber are integrally formed, the bearing bracket and the end cover for mounting the shaft seal part are separate parts, so the structure is easy to disassemble, resulting in high quality. A submersible electric motor for driving a pump can be provided.

Since the bearing bracket is placed in the frame and the frame, the bearing bracket and the end cover form a room for arranging the shaft seal mechanism, the gap that directly contacts the pumping liquid is only the fitting part of the frame and the end cover. Therefore, it is possible to reduce the gap portion where crevice corrosion is likely to occur.

[Brief description of drawings]

FIG. 1 is a sectional view of an upper part of an underwater electric motor having a shaft seal structure according to the present invention, and FIG. 2 is a sectional view showing an entire structure of an underwater electric motor for driving a pump having the shaft seal structure.
The figure is a cross-sectional view of a conventional underwater electric motor that drives a fresh water pump. In the figure, 11 ... frame, 12 ... stator core, 13 ... rotor core, 14 ... stator coil, 15 ... main shaft, 16 ...
Oil seal, 17 …… Radial bearing metal, 18 …… Upper bracket, 20 …… End cover, 21 …… Room, 22 …… Mechanical seal, 23 …… Oil seal, 24 …… Seal cover, 25 …… Sand slinger , 27 …… Seal case.

Claims (2)

[Scope of utility model registration request] 1. A stator core is provided in a frame which is in contact with a pumped liquid, and a rotor core through which a main shaft penetrates is provided at a central portion of the stator core, and both ends of the main shaft are rotatably supported by bearings. In the shaft seal structure of the pump driving submersible electric motor having a structure in which a shaft seal mechanism is provided at a predetermined position of the main shaft, in the frame, the end cover provided at the frame end, and the rotor core side from the end cover and inside the frame. A bearing bracket arranged in the chamber to form a chamber, and the shaft seal mechanism is disposed in the chamber.
The bearing bracket has its outer circumference fitted to the inner circumference of the frame and is fixed by a stopper attached to the inner circumference of the frame, and the end cover is fixed to the frame end by a bolt whose tip is screwed to the bearing bracket. A shaft seal structure for a submersible electric motor for driving a pump, which is characterized in that 2. The utility model registration claim (1), wherein the shaft seal mechanism is housed in a seal cover, and the seal cover is fitted in a through hole provided in the center of the end cover. A shaft seal structure for a submersible electric motor for driving a pump according to the item 1).