JPH0223082Y2 - - Google Patents

Description

[Detailed description of the invention] [Purpose of the invention] "Field of industrial application" This invention relates to an expansion absorption device for a liquid-sealed submersible electric motor.

"Prior Art" The pressure of the sealed liquid in a sealed liquid submersible motor is increased due to the expansion of the sealed liquid and the gas contained therein due to the operation of the motor. In order to absorb the expansion of the sealed liquid, an expansion absorbing device such as a diaphragm or a bellows is provided, but conventionally it is provided on the side near the upper output shaft of the sealed liquid submersible motor, or in the center of the lower part.

``Problem that the invention aims to solve'' When an expansion absorption device is installed on the top of a liquid-sealed submersible motor, the upper bearing for the motor shaft and the shaft sealing device are concentrated in the upper part of the liquid-sealed submersible motor. Some sealed liquid type submersible motors for pumps used for pumps have a suction casing arranged around the outer periphery of the motor frame and a suction passage around the upper part of the sealed liquid type submersible motor. Therefore, disposing an expansion absorbing device in this part cannot afford to complicate the structure, and in a pump using a sealed liquid submersible motor having a suction passage around the upper part, it becomes an obstruction to the suction passage. Another disadvantage is that the minimum suction water level of a pump using a sealed liquid type submersible motor in which the suction casing is disposed around the outer periphery of the motor frame and is attached to the motor frame is high.

Many sealed liquid type submersible motors that are equipped with one expansion absorption device in the center of the lower part are equipped with, for example, a diaphragm. However, the amount of adjustment may be small with one diaphragm, and if the diameter is increased to increase the amount of adjustment, the rubber will bend irregularly during operation, causing the compression spring that supports the diaphragm to get caught, the rubber to break, and the diaphragm to be damaged. The support plate of the compression spring may come off the rubber part, causing damage to the rubber. Furthermore, if it is stretched in the longitudinal (height) direction, the diaphragm is crushed from the side, causing the compression spring to get caught in the rubber, resulting in damage to the rubber and malfunction, as well as lengthening the motor and increasing costs. A similar problem occurs when a bellows is used as an expansion absorbing device for the sealed liquid.

This invention eliminates the above-mentioned drawbacks of the expansion and absorption device for the sealed liquid in a sealed liquid submersible motor, and creates a sealed liquid submersible motor equipped with an expansion absorption device that has a simple configuration, a large amount of adjustment, and can shorten the overall length of the motor. The purpose is to provide.

[Structure of the idea]

``Means for solving the problem'' This idea has upper and lower brackets fixed to the upper and lower ends of the frame, a suction casing that forms a suction passage around the outer periphery of the frame, and a flexible thin plate separating and sealing the inside and outside of the motor. This sealed liquid type submersible motor has a plurality of sealed liquid expansion and absorption devices in the lower bracket.

"Operation" By adjusting the number of expansion and absorption devices, it is possible to adapt to the expansion and contraction of the sealed liquid of the sealed liquid submersible motor.

"Example" Hereinafter, an example of this invention will be described according to the drawings. FIG. 1 is a longitudinal sectional view, and FIG. 2 is a bottom view of FIG. 1.

The motor frame 1 is provided with outer flanges at its upper and lower ends, an upper bracket 2 is fitted into the upper end via a sealing ring 3 and fixed with bolts 4, a lower bracket 5 is fitted into the lower end via a sealing ring 6, and a bolt 7 is fitted into the motor frame 1.
Fixed by The motor shaft 8 slides into radial metals 9 and 11 that are fitted into and fixed to the upper and lower brackets 2 and 5, respectively, to support the radial load.
The lower end of the motor shaft 8 engages with a floating thrust bearing 12 supported by the lower bracket 5 to carry a downward thrust, and an upward thrust is applied to the motor shaft 8 by a floating thrust bearing 13 supported by the upper bracket 2. The thrust force is supported. The thrust bearings 12 and 13 are the same in the vertical direction but opposite to each other.

Motor shaft 8 between upper and lower radial metals 9 and 11
A rotor 14 is fitted and fixed to the motor frame 1, and a stator 15 is fitted and fixed to the motor frame 1 with a space between the rotor 14 and the stator 15. The lower bracket 5 has a recess that communicates with the inside of the motor chamber through a communication hole 16 made in the wall 25 on which the coil end support rubber 20 of the lower coil of the stator 15 is placed, around the boss portion into which the lower radial metal 11 is fitted. A diaphragm chamber 17 is provided from below, and a diaphragm 18 is fitted into the diaphragm chamber 17, and a presser plate 21 with a flange hole 19 of the diaphragm 18 comes into contact with the diaphragm chamber 17, and the periphery of the diaphragm 18 is held by bolts 22. 21 and are fastened together to the lower bracket 5. 23 contacts the periphery of the upward convex seat at the center of the holding plate 21 and the bottom of the diaphragm 18;
This is a conical coil-shaped compression spring inserted between the spring receiving plate 24 and the spring receiving plate 24 fitted into the projection at the center of the bottom of the diaphragm 18.

A suction casing 26 made of a cylindrical sheet metal and having a number of holes communicating inside and outside is fitted into the upper and lower brackets 2 and 5, and is fixed with bolts 27 and 28.

The upper bracket 2 is provided with a fitting part 29 into which a pump suction cover (not shown) is fitted, and a female thread 31 for fastening.

A mechanical seal 34 is fitted into the shaft seal case 33 which is fitted into the upper bracket 2 and fixed by a bolt 32, and an oil seal 30 which is fitted into the shaft seal case 33 on the outside side and slides against the motor shaft 8, and which is fitted into the motor shaft 8. The electric motor shaft 8 is fixed, and the lip portion is sealed by a sand slinger 35 that approaches a seal plate fitted into the outer periphery of the cylindrical portion at the upper end of the shaft seal case 33, so that the motor shaft 8 protrudes upward.

The suction passage 36 formed between the suction casing 26 and the motor frame 1 has a hollow cylindrical shape determined approximately by the inner diameter of the suction casing 26 and the outer diameter of the motor frame 1. On the other hand, the suction passage at the upper end of the suction cover just in front of the impeller has a hollow cylindrical shape determined by the outer diameter of the end of the impeller on the suction port side and the outer diameter of the shaft joint that is fitted and fixed to the end of the motor shaft 8 (not shown). The suction passage 37 in the upper bracket 2 is shaped so that it does not create a dead water region in terms of flow through the suction passage 36 and the suction passage of the suction cover, and does not generate vortices.

Between the inner and outer members 39 and 38 of the upper bracket 2 is a rectifying plate 4 that has the function of rectifying the flow and connecting the inner and outer members.
1 is provided. An introduction tunnel 43 for a cable 42 is integrally provided in one of the rectifier plates.

The floating thrust bearings 12 and 13 are held in such a way that a thrust pad 45 whose center is supported by a fulcrum 44 corresponding to the end surfaces of the upper and lower brackets 2 and 5 does not rotate relative to a thrust disk 46 fitted and fixed to the motor shaft 8. Thrust carbon plate 47
It's rubbing against the surface. The thrust pad 45 is prevented from rotating by fitting two legs 48 into holes located in the axial direction from the end faces of the upper and lower brackets 2 and 5, respectively. One of the legs 48 of each thrust pad protrudes into a circumferential groove provided on the outer periphery of the boss of the upper and lower brackets 2, 5, and the boss of the upper and lower brackets 2, 5 is inserted into the notch provided in the leg 48. It is held by an O-ring-shaped elastic ring 49 that passes through a circumferential groove on the outer periphery. The elastic ring 49 prevents the thrust pad 45 from falling off from the upper and lower brackets 2 and 5 during assembly.

When the electric motor is energized, the rotor 14 and the electric motor shaft 8
rotates. The temperature of the sealed liquid rises due to heat generated by the stator 15 and rotor 14 due to electrical loss, friction loss in the upper and lower radial metals 9, 11, upper and lower thrust bearings 12, 13, fluid friction loss of the filled liquid, etc., and the sealed liquid itself and the included gas expands. This increase in volume enters the diaphragm chamber 17 through the communication hole 16, and deforms and contracts the diaphragm 18 against the elasticity of the compression spring 23 and the diaphragm 18. In this way, the pressure increase in the sealed liquid is suppressed to a constant temperature.

In the embodiment, there are three sets of expansion and absorption devices for the sealed liquid using the diaphragm 18, etc., but it is preferable to select from two to four sets depending on the amount of expansion of the sealed liquid.

Although the embodiment is arranged excluding the center part, even if one of the expansion absorbers is arranged in the center part, the height of the expansion absorber will be lower, so the total length of the sealed liquid submersible motor will be shorter. Become.

[Effect of idea]

This idea provides multiple expansion and absorption devices for the sealed liquid in the lower bracket of a liquid-filled submersible motor, so (1) one expansion and absorption device has an appropriate size;
No permanent deformation or damage will occur due to expansion of the filled liquid.

(2) If the expansion and absorption devices are standardized so that the number of expansion and absorption devices is determined according to the size and type of the sealed liquid submersible motor, the number of types of expansion and absorption devices will be extremely small.

(3) Since the height of one of the expansion and absorption devices is lower than that of the conventional example, the height of the sealed liquid submersible motor will be lower regardless of the arrangement. It can be made even lower.

(4) In the embodiment, a lower radial metal is placed at the bottom of the lower bracket, a thrust bearing is placed at the top of the lower radial metal, and an expansion absorption device is placed around the boss of the lower bracket into which the lower radial metal is fitted. The total length of the liquid-sealed submersible motor becomes extremely short.

[Brief explanation of the drawing]

FIG. 1 is a longitudinal sectional view of an embodiment of the invention, and FIG. 2 is a bottom view of FIG. 1. 1...Motor frame, 2...Upper bracket, 3...Sealing ring, 4...Bolt, 5...Lower bracket, 6...Sealing ring, 7...Bolt, 8...
Electric motor shaft, 9, 11...Radial metal, 12,
13... Thrust bearing, 14... Rotor, 15...
... Stator, 16 ... Communication hole, 17 ... Diaphragm chamber, 18 ... Diaphragm, 19 ... Hole, 2
0...Coil end support rubber, 21...Press plate,
22... Bolt, 23... Compression spring, 24... Spring receiving plate, 26... Suction casing, 27, 28...
... Bolt, 29 ... Fitting part, 30 ... Oil seal, 31 ... Female thread, 32 ... Bolt, 33 ...
Shaft seal case, 34... Mechanical seal, 35...
... Sand slinger, 36, 37 ... Suction passage, 3
8... External material, 39... Internal material, 41... Current plate, 42... Cable, 43... Introducing tunnel,
44...Fully point, 45...Thrust pad, 46...
... Thrust disk, 47... Thrust carbon plate, 48... Leg, 49... Elastic ring.

Claims (1)

[Scope of utility model registration request] The upper and lower brackets are fixed to the upper and lower ends of the frame, a suction casing is provided on the outer periphery of the frame to form a suction passage, and the inside and outside of the motor are separated and sealed with flexible thin plates. 1. A sealed liquid submersible electric motor, characterized in that a plurality of expansion absorption devices for sealed liquid are provided in a lower bracket.