JPH05219687A - Canned motor pump - Google Patents

Abstract

(57) [Summary] [Purpose] To provide a canned motor pump that is cooled in the same manner as in horizontal installation even when installed in a tilted manner. A canned motor pump has an impeller 2 inside a pump casing 1, a pump portion fixed to the front end of a rotor shaft 3 by the impeller 2, and a stator can 6.
A stator 7 is sealed in the stator chamber, and a rotor 8 fixed to the rotor shaft 3 is provided in the rotor chamber inside the stator can 6.
A spiral groove 23 is formed on the outer peripheral surface of the rotor shaft 3. The spiral groove 23 performs a pumping action when the cooling liquid passage is closed, and the pumping action forcibly sends the liquid in the front rotor chamber 18 from the front rotor chamber 18 to the rear rotor chamber 21. This causes a difference in pressure between the front rotor chamber 18 and the rear rotor chamber 21 to move the rotor 8 to the front rotor chamber 18 side.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a canned motor pump which can be cooled even in a tilted installation as in a horizontal installation.

[0002]

2. Description of the Related Art The basic structure of a canned motor pump of this type can be roughly divided into a pump portion and a motor portion as shown in FIG. 4 (for example, Japanese Patent Publication No. 2-19700).

This pump portion is a pump casing 101.
Has an impeller 102 inside, and the impeller 102 is fixed to the front end of the rotor shaft 103. The pump section uses the impeller 10 to suck the liquid sucked from the suction port 104.
The pressure is increased by 2 to be discharged from the discharge port 105.

Further, the motor section is a stator can 1
A stator 108 is provided in a stator chamber sealed by 06, and a rotor 108 fixed to the rotor shaft 103 by press fitting or adhesion is arranged inside the stator can 106 in the rotor chamber. The rotor shaft 103 is provided with a through hole 109 in the axial direction.
A rotor can 110 is provided on the outer periphery of the. The rotor shaft 103 includes a front bearing 112 of a front bearing housing 111 and a rear bearing 11 of a rear bearing housing 113.
It is supported by 4 and. In addition, the impeller 102
Rear wear ring 115 and front bearing housing 11
A fixed orifice 116 is formed from the liner ring of 1. Also, the rear wear ring 1 of the impeller 102
A thrust balance chamber 117 is formed inside 15 and at the front end portion of the front bearing housing 111. The front bearing housing 111 is provided with a flow path 119 that connects the thrust balance chamber 117 and the front rotor chamber 118. The fixed orifice 116, the thrust balance chamber 117, and the flow path 119 form an automatic slight balance mechanism. Also, the rear bearing housing 113
At the mounting portion of the rear bearing 114, a variable orifice 120 formed by the rear end surface of the rotor shaft 103 and the bottom flat surface of the rear bearing housing 113 is provided. The through hole 109 that opens and the rear rotor chamber 121 communicate with each other. A forward thrust load applied to the rotor shaft 103 is generated by the thrust collar 122.
It is designed to be received by the thrust surface of 2.

According to the canned motor pump having such a structure, the liquid sucked from the suction port 104 of the pump casing 101 is pressurized by the impeller 102 and discharged from the discharge port 105. A part of the liquid discharged to the discharge port 105 passes through the fixed orifice 116 and flows into the thrust balance chamber 117. This liquid flows into the front rotor chamber 118 through the flow path 119. The liquid that has flowed into the front rotor chamber 118 passes between the stator can 106 and the rotor can 110 and flows into the rear rotor chamber 121. The liquid in the rear rotor chamber 121 flows back to the suction port 104 through the variable orifice 120 and the through hole 109.

As a result, the stator 107 and the rotor 1
08 and cools the front bearing 112 and the rear bearing 114.
The lubrication can be improved.

[0007]

However, in the above-mentioned conventional canned motor pump, as shown in FIG. 5, when the rear part of the canned motor pump is installed so as to be inclined downward from the front part thereof. , The rotor shaft 3 is lowered due to the weight of the impeller 102 and the rotor 108, and the rear end surface of the rotor shaft 103 has the rear bearing housing 1
13 is in contact with the surface. In such a state, the cooling liquid passage is blocked and the cooling water does not circulate.

When such a state occurs, the rotor shaft 3 is normally pushed back by the automatic slide balance mechanism of the canned motor pump, but since the rotor shaft 3 is inclined, the automatic slide balance is performed. The force of the mechanism loses the weight of the impeller 102 and the rotor 108, and remains in the lowered state.

In this situation, since the cooling water does not flow, the temperature of the motor rises from the normal state, and the positional relationship between the stator 107 and the rotor 108 shifts, so that the efficiency is lowered.

SUMMARY OF THE INVENTION It is an object of the present invention to solve the above-mentioned drawbacks and to provide a canned motor pump in which the horizontally mounted canned motor pump is cooled in the same manner as in the horizontally installed canned motor pump. To do.

[0011]

In order to achieve the above object, a canned motor pump of the present invention has an impeller inside a pump casing, the impeller being fixed to the front end of a rotor shaft, A canned motor pump having a stator in a stator chamber sealed by a stator can, and a motor unit in which a rotor fixed to the rotor shaft is arranged in a rotor chamber inside the stator can. It is characterized in that a spiral groove is formed on the shaft.

The spiral groove of the rotor shaft is preferably formed longer than the length of the object fixed to the rotor shaft. Further, the spiral groove of the rotor shaft is arranged so as not to be exposed in the rotor chamber on the pump casing side when the cooling liquid passage is not blocked.

[0013]

According to the above construction, by providing the spiral groove on the rotor shaft, the spiral groove causes a pumping action when the cooling liquid passage is closed, and the pumping action causes the liquid in the front rotor chamber to flow from the front rotor chamber. It is forcibly sent to the rear rotor chamber. As a result, a pressure difference is created between the two chambers, and the rotor is moved to the front rotor chamber side. As a result, the rear end surface of the rotor shaft comes into contact with the rear bearing housing to open the coolant passage that has been blocked, so that the rotor and the stator can be cooled, and the bearing of the rotor shaft can be lubricated. Become.

[0014]

The present invention will be described below with reference to the illustrated embodiments.

FIG. 1 is a sectional view showing an embodiment of a canned motor pump of the present invention. 2A is a perspective view showing a rotor shaft used in the embodiment of the present invention, and FIG.
FIG. 4 is a plan view showing the rotor shaft.

In these figures, the canned motor pump can be roughly divided into a pump section and a motor section. This pump section has an impeller 2 inside a pump casing 1,
Moreover, the impeller 2 is fixed to the front end of the rotor shaft 3.
The motor unit has a stator 7 in a stator chamber sealed by a stator can 6, and the rotor shaft 3
The rotor 8 fixed by press-fitting or adhesion to the above is disposed inside the rotor chamber inside the stator can 6. A through hole 9 is provided in the rotor shaft 3 in the axial direction, and a rotor can 10 is provided on the outer circumference of a rotor 8 fixed to the rotor shaft 3.
Is provided. The rotor shaft 3 is supported by a front bearing 12 of a front bearing housing 11 and a rear bearing 14 of a rear bearing housing 13. A fixed orifice 16 is provided at the rear end of the impeller 2. The fixed orifice 16 is formed by the rear wear ring 15 of the impeller 2 and the liner ring of the front bearing housing 11. A thrust balance chamber 17 is formed inside the fixed orifice 16. The thrust balance chamber 17 is formed inside the rear wear ring 15 of the impeller 2 and the front end portion of the front bearing housing 11. The front bearing housing 11 is provided with a flow path 19 that connects the thrust balance chamber 17 and the front rotor chamber 18. This fixed orifice 16,
The thrust balance chamber 17 and the flow path 19 constitute an automatic slight balance mechanism. A variable orifice 20 is provided at the mounting portion of the rear bearing 14 of the rear bearing housing 13. This variable orifice 20 is
It is formed by the rear end surface of the rotor shaft 3 and the bottom flat surface of the rear bearing housing 13. Through the variable orifice 20, the through hole 9 opened at the rear end surface of the rotor shaft 3 and the rear rotor chamber 21 are communicated with each other. The thrust load applied to the rotor shaft 3 in the forward direction is received by the thrust collar 22 on the thrust surface of the front bearing 12.

Further, on the outer peripheral surface of the rotor shaft 3, as shown in FIG.
As shown in FIGS. 2A and 2B, the spiral groove 23 is formed. The spiral groove 23 is formed like a right-hand screw when the rotor shaft 3 is rotated to the right, for example.

The operation of the embodiment thus constructed is shown in FIG.
Also, description will be made with reference to FIG. 3 based on FIG.

FIG. 3 is an explanatory view for explaining the operation of the embodiment of the present invention, FIG. 3 (a) is a view when the cooling water is not recirculated, and FIG. 3 (b) is returned to a normal state. FIG.

First, the canned motor pump is shown in FIG.
As shown in (a), it is assumed that they are installed at an angle.
At this time, the weight of the impeller 2 and the rotor 8 brings the rotor shaft 3 into contact with the inner surface of the rear bearing housing 13. When the canned motor pump is operated in such a state, the rotor 8 rotates, and the rotor shaft 3
A pump effect is generated by the spiral groove 23 engraved in, and the liquid in the front rotor chamber 18 is sucked in as shown by an arrow X in the drawing.
It is sent to the rear rotor chamber 21 through the gap between the spiral groove 23 and the rotor 8 / rotor shaft 3 as shown by arrow Y in the figure. That is, the liquid inside the front rotor chamber 18 is forcibly moved to the rear rotor chamber 21. The indoor pressure of the front rotor chamber 18 is Pf, and the indoor pressure of the rear rotor chamber 21 is Pb.
Then, when the liquid in the front rotor chamber 18 moves to the rear rotor chamber 21 side, the pressure relationship between the two chambers 18 and 21 becomes Pf <Pb, and a force F that pushes the rotor 8 to the right side in the drawing is generated. Thus, the rotor shaft 3 moves to the front rotor chamber 18 side. This allows the canned motor pump to
As shown in FIG. 3B, the rotor 8 moves to the front rotor chamber 18 side.

Accordingly, the rear end surface of the rotor shaft 3 is closed by the rear end surface of the rotor shaft 3 coming into contact with the inner surface of the rear bearing housing 13, and the rear end surface of the rotor shaft 3 is moved by the rightward movement of the rotor shaft 3. Rear bearing housing 1
By releasing from the inner surface of 3, the cooling liquid can be opened and the cooling liquid can be circulated. As a result, even with the canned motor pump installed in an inclined state, the stator 7 and the rotor 8 can be cooled, and the front bearing 12 and the rear bearing 14 are lubricated.

When the rotor shaft 3 moves forward, the spiral groove 23 is hidden in the front bearing 12. As a result, the forced liquid flow in the gap between the rotor 8 and the rotor shaft 3 is cut off, and the force F for moving the rotor shaft 3 forward disappears, and the thrust load applied to the front bearing 12 is reduced. Disappear. After that, the thrust balance mechanism operates in the same manner as in the conventional case, and the correct positional relationship between the stator 7 and the rotor 8 is maintained.

Also in the above embodiment, the operation of the pump and the operation of the cooling liquid passage are the same as those of the conventional device.

[0024]

As described above, according to the present invention, since the spiral groove of the rotor shaft is provided, when the cooling liquid passage is closed, the liquid in the front rotor chamber is removed by the pumping action of the spiral groove. By forcibly sending it to the rear rotor chamber to form a pressure difference between the two chambers and moving the rotor to the front rotor chamber side, the following effects are achieved.

(1) In particular, it is possible to take measures against tilt installation without changing the structure of the pump.

(2) It is possible to maintain the conventional motor efficiency even when installed at an inclination.

(3) Since it can be installed at an inclination, the range of use conditions is expanded.

[Brief description of drawings]

FIG. 1 is a sectional view showing an embodiment of a canned motor pump of the present invention.

FIG. 2 is a view showing a rotor shaft having a spiral groove used in the embodiment.

FIG. 3 is a view for explaining the operation of the same embodiment.

FIG. 4 is a sectional view showing a conventional canned motor pump.

FIG. 5 is a view showing a case where a conventional canned motor pump is installed at an inclination.

[Explanation of symbols]

 1 Pump Casing 2 Impeller 3 Rotor Shaft 6 Stator Can 7 Stator 8 Rotor 9 Through Hole 11 Front Bearing Housing 12 Front Bearing 13 Rear Bearing Housing 14 Rear Bearing 18 Front Rotor Chamber 19 Flow Path 20 Variable Orifice 21 Rear Rotor Chamber 23 Spiral groove

Claims (3)

[Claims] 1. A pump casing has an impeller inside, the impeller has a pump portion fixed to a front end of a rotor shaft, and a stator in a stator chamber sealed by a stator can, and fixed to the rotor shaft. A canned motor pump comprising a rotor and a motor portion arranged inside a rotor chamber inside the stator can, wherein a spiral groove is formed on a rotor shaft in the rotor chamber. 2. The spiral groove of the rotor shaft is formed longer than the fixed object on the rotor shaft.
The described canned motor pump. 3. The canned motor pump according to claim 1, wherein the spiral groove of the rotor shaft is arranged so as not to be exposed to the rotor chamber on the pump casing side when the cooling liquid passage is not blocked.