CN203554148U - Submerged motor - Google Patents

Abstract

The utility model relates to a submerged motor which comprises a stator and a rotor. The improvement is as follows: the rotor has an axial displacement h in the axial direction relatively to the stator, and the axial displacement h enables the motor to produce an axial magnetic pull component F during normal operation to offset part of the axial load or the entire axial load F0. According to the submerged motor, the principle that the stator and the rotor of the motor can be in axial displacement to produce an axial force is ingeniously utilized, so that the stator and the rotor of the submerged motor are designed in an axial displacement manner to produce a proper axial force to offset part of the axial load or the entire axial load of the motor. Therefore, the problems of excessively large axial load and difficulty in balancing the axial force of the submerged motor are solved; on one hand, a bearing of the motor is protected, and on the other hand, the service life of the motor is prolonged; and meanwhile, no extra production cost is increased. Under the condition that the same safety coefficient is guaranteed, the specification and model of a thrust bearing is properly reduced sometimes, so that the manufacturing cost of the submerged motor is lowered.

Description

A kind of submersible electric motor

Technical field

The utility model belongs to electromechanical equipment field, is specifically related to a kind of submersible electric motor.

Background technology

Submersible pump, as requisite plant equipment in a kind of national economy, is widely used in all trades and professions such as mine metallurgy, national defense construction, electrical production, petrochemical industry, municipal water conservancy, field irrigation, has very consequence and effect.It consists of submersible electric motor and water pump, and submersible electric motor is the power source of pump, and pump is the load of submersible electric motor, and the two is connected by shaft coupling.Inherent characteristic due to pump configuration, when liquid is flowed through the pump housing, can to the pump housing, have a synthetic axial thrust at impeller front and rear cover plate and impeller import and export, and be delivered on submersible electric motor by rotating shaft, finally the thrust bearing by submersible electric motor bears.In order to guarantee the reliability of thrust bearing, guarantee the useful life of submersible pump unit.Existing solution mainly contains two: the one, on pump structure, make an issue of, such as sealing ring being set on back shroud of impeller, opening balancing hole etc. at impeller hub place, but this can only reduce the axial thrust of pump to motor to a certain extent, can not eliminate completely, the contrary loss that has also brought flow and lift, the harmful effects such as the operating efficiency reduction of unit; The 2nd, strengthen the specifications and models of submersible electric motor thrust bearing or select the thrust bearing of better material, this way no doubt can play a role, but greatly increased the cost of motor, change can to when serious whole axle frenulum, even have influence on the profile installation dimension of whole submersible pump unit.

Summary of the invention

In order to overcome the deficiency of prior art scheme, by motor being carried out to the stator and rotor design that axially misplaces, the utility model provide a kind of both effects significantly, be easy to realize, additionally do not increase again the submersible electric motor of cost.

Concrete technical solution is as follows:

A kind of submersible electric motor comprises stator and rotor, described rotor and stator shaft orientation stagger mutually, form an axial displacement h, described axial displacement h can produce an axial magnetic pull component F in the time of can making motor normally work, for offsetting part or all of axial load F ₀.

Described axial displacement h is 1～10mm.

For the submersible electric motor of horizontal operation, axial load F ₀the axial thrust that all comes from pump; For the submersible electric motor of vertical operation, load F ₀for the axial thrust of pump and making a concerted effort of rotor self gravitation.

Because submersible electric motor is to work in potential water, its unique operational environment has determined generally there is no radial ducts in its type of cooling design, therefore the easy calculating of its axial force F can be by following formula:

$F=8.088\left(\frac{m}{f}\right)\·\left(\frac{I_{m0}{E}_0}{L_0}\right)\·{\left(\frac{L_0}{L}\right)}^2\·\frac{\∂L}{\∂H}$

F-axial force in formula, kg;

M-number of phases;

F-frequency, Hz;

I _m0-magnetizing current, A;

E ₀-phase voltage, V;

L ₀-actual unshakable in one's determination long, mm;

L-active iron core is long, mm; $L=L_0+g\·\left(\frac{\mathrm{\ΔL}}{g}\right).$

Wherein, g-gas length, mm;

the long effectively long right rate of change unshakable in one's determination of-per unit air gap, its value is relevant to the ratio of h/g, can be checked in by correlation experience curve;

the rate of change of-active iron core length to axial displacement, its value is relevant to the ratio of h/g, can be checked in by correlation experience curve.

The utility model has utilized the axial dislocation of motor stator and rotor can produce the principle of axial force cleverly, by submersible electric motor being carried out to stator, rotor axial dislocation design, produce a sizeable axial force, be used for offsetting the part or all of axial load of motor, solved the problem that submersible electric motor axial load is excessive, axial force is difficult to balance; Protect motor bearings on the one hand, extended on the other hand the useful life of motor; Meanwhile, additionally do not increase production cost.In the situation that guaranteeing identical coefficient of safety, sometimes can also suitably reduce the specifications and models of thrust bearing, to reduce the manufacturing cost of submersible electric motor.

Accompanying drawing explanation

Fig. 1 is electric pump set structure schematic diagram.

Fig. 2 is the I place partial enlarged drawing of Fig. 1.

Sequence number in upper figure: stator 1, rotor 2, thrust bearing 3.

Embodiment

Below in conjunction with accompanying drawing, by embodiment, the utility model is described further.

Embodiment

Referring to Fig. 1, a kind of ZDB type axial-flow electric pump unit unit of vertical installation, flow 9500m ³/ h, lift 8.85m, impeller outer diameter 870mm, internal diameter 450mm, under rated condition, the axial load 1530kg(of motor is the axial thrust of water pump to motor), add and the own wt 1140kg of rotor obtain load F ₀=1530+1140=2680kg, direction is for pointing to shaft extension direction.Load F ₀all the thrust bearing by motor bears, and the submersible electric motor model of this unit apolegamy is YQGN990-16 (355kW, 10kV), there is no radial ducts in structure, and preliminary project is used self-aligning thrust roller bearing 29428(GB/T5859-1994).The correlation technique parameter of this submersible electric motor is: magnetizing current I _m0=17.8A, phase voltage E ₀=5774V, long L=540mm unshakable in one's determination, gas length g=1.5mm.Now, motor is carried out to the axial 5mm dislocation of stator 1, rotor 2 design, rotor 2, with respect to stator 1 along the shaft extension direction mobile 5mm that staggers, calculates the axial force producing after 5mm axial displacement

$F=8.088\·\left(\frac{3}{50}\right)\·\left(\frac{17.8\×5774}{540}\right)\·{\left(\frac{540}{543}\right)}^2\·(1.95+0.7*2)=303\mathrm{kg},$ Make the load of motor bearings reduce to 2377kg by 2680kg.In the case, if do not consider to change bearing, can greatly improve the coefficient of safety of submersible electric motor up-thrust bearing 3, extend motor useful life; If consider to change bearing, can select as calculated the self-aligning thrust roller bearing 29426(GB/T5859-1994 of little No.), to cost-saving, there is out and out economic implications.

Theoretical foundation of the present utility model is: alternating current machine forms rotating magnetic field after energising, in rotor, produce induced current, after rotor magnetization, because the path of magnetic resistance minimum is preferentially selected in the current path of the magnetic line of force, and shorter by the distance of air gap, the magnetic resistance of generation is less.If motor stator and rotor iron core complete matching, this part electromagnetic attraction only acts on rotor radially, and mutual balance, and when stator and rotor complete matching not, at this moment the air gap between rotor is equivalent to be extended; When the magnetic line of force is attempted to pass through air gap with the shortest distance, just produced axial magnetic pull component, i.e. axial force F.

Claims (3)

1. a submersible electric motor, comprise stator and rotor, it is characterized in that: the stator shaft orientation of described rotor staggers mutually, form an axial displacement h, described axial displacement h can produce an axial magnetic pull component F in the time of can making motor normally work, for offsetting part or all of axial load F ₀.

2. a kind of submersible electric motor according to claim 1, is characterized in that: described axial displacement h is 1～10mm.

3. a kind of submersible electric motor according to claim 1, is characterized in that: for the motor of horizontal operation, and described load F ₀come from the axial thrust of pump to motor; For the motor of vertical operation, described load F ₀for making a concerted effort of axial thrust and rotor self gravitation.

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