JPH0622499A - Canned motor pump - Google Patents

Abstract

PURPOSE:To provide a highly reliable canned motor pump, using a bearing of such structure as to use the resiliency of a permanent magnet. CONSTITUTION:For radial bearings 28 and 29, on rotation side, permanent magnets 1 and 6b are set around the yokes 2 and 8 on rotation side, and the yokes are set onto the main shaft 23 through adaptors 3 and 9, and permanent magnets 4 and 10 are fit in, leaving small radial gaps between themselves and the permanents magnets 1 and 7, and these are set and fixed to covers 6 and 12. For a thrust bearing 30, permanent magnets 14 and 15 are set to both sides of one disc 13 mounted on the main shaft 23, and permanent magnets 16 and 18 are set and fixed in opposition to a cover 20, leaving small axial gaps.

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 provided with a radial bearing and an axial bearing which utilize the repulsive force of a permanent magnet.

[0002]

2. Description of the Related Art Conventional canned motor pumps use sliding bearings as bearings. FIG. 7 is a cross-sectional view showing the structure of a conventional canned motor pump using a plain bearing. As shown, the rotor 24 and the stator 25 of the canned motor
A slide bearing 53 on the side of the impeller 22 and a slide bearing 54 on the side of the opposite impeller are arranged on the side of the impeller on both sides of and, and a slide bearing 54 on the side of the opposite impeller. This is a configuration in which the plate 58 is arranged.

When the main shaft 23 rotates by starting the motor, the impeller 22 rotates and the fluid sucked from the suction port 26 is discharged from the discharge port 27. In FIG. 7, 55 is an impeller-side shaft sleeve, and 56 is a non-impeller-side shaft sleeve.

In the canned motor pump having the above structure, the sliding bearing is usually made of metal on the rotating side and carbon on the stationary side. Thrust generated by a pump or the like is divided into radial thrust and axial thrust depending on the direction. The radial thrust is received by the slide bearings 53 and 54 and the shaft sleeves 55 and 56, and the axial thrust is the slide bearings 53 and 54 and the thrust plate 5.
I received it at 7,58.

[0005]

In the canned motor pump having the above-mentioned conventional structure, during operation of the canned motor pump, the shaft sleeves 55 and 56 and the thrust plates 57 and 58, which are rotating parts, are slid on the fixed side. Bearing 53, 54
Since they rotate while making contact with each other, there is a drawback that the bearing and the like are worn. Further, since a part of the liquid flowing in the pump is circulated for the purpose of lubricating the bearing and cooling the canned motor, there is a drawback that the worn product is mixed in the liquid and the purity of the liquid is lowered. .

Further, as a means for solving the drawbacks of the slide bearing, a bearing using an electromagnet is also used. In this method, the rotating body is held in a non-contact state by electrical control. In case of a power failure or electric trouble, an auxiliary bearing for so-called touchdown is provided to prevent the electromagnets from coming into contact with each other even if the rotating body falls vertically downward due to its own weight. However, even in this method, when the electromagnet does not move in the event of an emergency, the rotating body itself falls vertically downward due to its own weight, and the auxiliary bearings for touchdown come into contact with each other. The disadvantage that the auxiliary bearing wears and the purity of the liquid is lowered cannot be solved.

[0007] In the case of plain bearings and electromagnet bearings, the canned motor pump is disassembled and investigated every time a bearing trouble occurs, and in many cases, the bearing parts must be replaced with new ones. I won't. At the time of this decomposition, it is common to discard all the liquid handled by the pump, which is not preferable for the environment.

The present invention has been made in view of the above-mentioned problems, and in order to eliminate the above-mentioned problems, it has a structure in which a permanent magnet is used for the bearing, and the rotating body can be kept in a non-contact state under any conditions. An object of the present invention is to provide a highly reliable canned motor pump having no bearing wear.

[0009]

In order to solve the above problems, according to the present invention, one set of radial bearings is arranged on the impeller and the opposite impeller side of a rotor and a stator of a canned motor, and an axial bearing is used as a main shaft. In the canned motor pump arranged at any position, the radial bearings on the impeller side and the counter impeller side each have one or a set of hollow cylinders on the outer periphery of the rotary side yoke having a hollow cylindrical shape on the rotation side. The permanent magnet is fitted, and the rotary yoke fitted with the permanent magnet is incorporated into the main shaft through the adapter. The fixed side to these permanent magnets is the inner peripheral surface of the fixed yoke and the outer peripheral surface of the rotary permanent magnet is A small radial gap is provided in the hollow cylindrical cylindrical permanent magnet or a set of permanent magnets, and these are assembled and fixed in the cover. What is the permanent magnet on the rotating side and the permanent magnet on the fixed side? The thrust bearing has a structure in which it repels each other in the radial direction, and the thrust bearing is a hollow cylindrical one or both side surfaces of one disk attached to the main shaft on the rotation side or one side surface of each of the two disks. A set of permanent magnets is incorporated, and one or a set of hollow cylindrical cylindrical permanent magnets or a set of permanent magnets, which are fitted to the fixed-side yoke, are provided on the fixed side so as to face the respective surfaces of these permanent magnets. Is fixed to the cover by providing an axial gap, and the permanent magnet on the rotating side and the permanent magnet on the stationary side repel each other in the axial direction.

[0010]

According to the present invention, the radial bearing has a structure in which the rotating permanent magnet and the stationary permanent magnet repel each other in the radial direction, and the axial bearing has the rotating permanent magnet and the stationary permanent magnet. Since they have a structure in which they repel each other in the axial direction, the rotating body can be kept in non-contact with the fixed side, wear of the bearing can be completely eliminated, and the purity of the liquid handled by the canned motor pump can be reduced. It is possible to obtain a highly reliable canned motor pump that maintains the above-mentioned value and has a dramatically increased life.

[0011]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a sectional view showing the structure of a canned motor pump according to the present invention. This canned motor pump has a rotor 2
Radial bearings 28 and 29 that support a radial load are arranged on both sides of the stator 4 and the stator 25, and an axial bearing (thrust bearing) 30 that supports an axial load is arranged at the end of the main shaft 23 opposite to the impeller 22. .

On the rotating side of the radial bearing 28 closer to the impeller 22, one or a pair of hollow cylindrical permanent magnets 1 is fitted on the outer peripheral surface of a hollow cylindrical yoke 2, and an adapter 3 is interposed therebetween. Is incorporated in the main shaft 23. On the fixed side facing the permanent magnet 1, one or a pair of hollow cylinders are formed on the inner peripheral surface of the yoke 5 so that there is a small gap a between the inner peripheral surface of the yoke 5 and the outer peripheral surface of the permanent magnet 1 on the rotating side. The permanent magnets 4 are fitted and they are assembled and fixed in the cover 6. The permanent magnet 1 on the rotating side and the permanent magnet 4 on the stationary side determine the polarities of the magnets so as to repel each other in the radial direction.

Similarly, for the other set of radial bearings 29, one or a set of hollow cylindrical permanent magnets 7 is fitted on the outer peripheral surface of the hollow cylindrical yoke 8 on the rotation side, and an adapter 9 is interposed therebetween. Is incorporated in the main shaft 23. On the fixed side with respect to the permanent magnet 7, one or a set of hollow cylindrical permanent magnets is provided so that the inner peripheral surface of the yoke 11 has a small gap b between the outer peripheral surface of the permanent magnet 7 on the rotating side. The magnets 10 are fitted, and they are assembled and fixed in the cover 12.
The permanent magnet 7 on the rotating side and the permanent magnet 10 on the fixed side determine the polarities of the magnets so as to repel each other in the radial direction.

On the rotation side of the axial bearing 30, the main shaft 2
One or a pair of permanent magnets 14 and 15 each having a hollow cylindrical shape are installed on both sides of the disk 13 attached to the disk 3. Then, on the fixed side, the yoke 1 is arranged so as to face the respective surfaces of the permanent magnets 14 and 15.
One or a pair of hollow-cylindrical permanent magnets 16 and 18 fitted in 7 and 19 are assembled and fixed in the cover 20 so that there are small gaps c and d in the axial direction. The permanent magnets 14 and 15 on the rotating side,
The permanent magnets 16 and 18 on the fixed side determine the polarities of the magnets so as to repel each other in the axial direction. Reference numeral 21 in FIG. 1 is an end cover.

2 (a), (b), (c) and (d),
It is a figure which shows the part of the radial bearing 28 near the impeller 22, and FIG.2 (a) and (c) show a cross section, and FIG.2 (b) and (d) are FIG.2 (a) and (c), respectively. ) Suction port 26
The cross section seen from the direction of is shown. 2 (a) and 2 (b) show a state in which it is assumed that the permanent magnet 1 on the rotating side and the permanent magnet 4 on the stationary side receive no radial load including its own weight. Since the permanent magnet 1 and the fixed permanent magnet 4 are balanced in repulsive force in the radial direction over the entire circumference, the clearance a is uniform over the entire circumference. That is, there is no eccentricity between the rotation-side axis and the fixed-side axis.

FIGS. 2 (c) and 2 (d) show a state in which a radial load W1r is applied to this bearing, for example, vertically downward. The radial load W1r acts so that the permanent magnet 1 on the rotating side descends vertically downward together with the main shaft 23. That is, there is an eccentricity d1 between the rotation-side axis and the fixed-side axis. In this eccentric state, the smaller the gap a is, the larger the repulsive force in the radial direction from the fixed permanent magnet 4 to the rotating permanent magnet 1 is. The vertical repulsive force R1s acts on the. The magnitude of the repulsive force R1s increases as the gap a decreases. Therefore, the gap a is repulsive force R1s =
Stabilizes in the gap that provides the radial load W1r.

3 (a), (b), (c), and (d),
It is a figure which shows the part of the radial bearing 29 on the opposite side of the impeller 22, FIG.3 (a) and (c) show a cross section, and FIG.3 (b) and (d) are FIG.3 (a) and (c), respectively. ) Suction port 26
The cross section seen from the direction of to the axial direction is shown. Figure 3
(A) and (b) are the states in which it is assumed that the permanent magnet 7 on the rotating side and the permanent magnet 10 on the stationary side do not receive any radial load including its own weight. Since the permanent magnet 7 and the permanent magnet 10 on the fixed side balance the repulsive force in the radial direction over the entire circumference, the gap b is uniform over the entire circumference. That is, there is no eccentricity between the rotation-side axis and the fixed-side axis.

FIGS. 3 (c) and 3 (d) show a state in which a radial load W2r is applied to this bearing, for example, vertically downward. By the action of the radial load W2r, the permanent magnet 7 on the rotating side moves downward together with the main shaft 23 in the vertical direction. That is, there is an eccentricity d2 between the rotation-side axis and the fixed-side axis. In this eccentric state, the smaller the gap b is, the larger the repulsive force in the radial direction from the fixed permanent magnet 4 to the rotating permanent magnet 1 is. Therefore, the total repulsive force over the entire circumference is represented by the rotating permanent magnet. The vertical repulsive force R2s acts on the. The magnitude of the repulsive force R2s increases as the gap b decreases. Therefore, the gap b is repulsive force R2s =
Stabilizes in the gap that provides the radial load W2r.

4A and 4B are views showing a portion of the axial bearing 30, and FIG. 4A shows the permanent magnets 14 and 15 on the rotating side, the permanent magnet 16 on the stationary side, and the permanent magnet 18. Is assumed to receive no axial load at all, in this case, since the axial gap c and the axial gap d are made equal at the time of mounting, the fixed permanent magnet 16 rotates. The direction of the repulsive force T3a exerted on the side permanent magnet 14 is the opposite to the direction of the repulsive force T4a exerted on the rotating side permanent magnet 15 by the fixed side permanent magnet 18, and the magnitude thereof is equal.

FIG. 4B shows a state in which an axial load Ta is applied to this bearing, for example, in the direction of the impeller 22. When the axial load Ta acts, the disk 13 on the rotating side includes the permanent magnets 14 and 15 and moves together with the main shaft 23 in the direction of the impeller 22. In this moved state, the gap c is smaller than the gap d. The smaller the gap in the axial direction, the larger the repulsive force in the axial direction. Therefore, the repulsive force T3a exerted by the fixed permanent magnet 16 on the rotating permanent magnet 14 and the fixed permanent magnet 18 exerted on the rotating permanent magnet 15. Compared with the repulsive force T4a, the directions are opposite and the magnitude is larger. Therefore, the gaps c and d are stable such that T3a-T4a = Ta.

2 (c) and (d) and FIGS. 3 (c) and (d), the balance in the state where the permanent magnet on the rotating side is lowered in the vertical direction will be described, and in FIG. 4 (b),
The balance when the disk 13 moves toward the impeller 22 has been described. During operation of the canned motor pump, the rotating body receives a radial load and an axial load at the same time, so there is an eccentricity between the rotating side axis and the fixed side axis in the radial direction, and in the axial direction. , The gap c is not equal to the gap d.

FIG. 5 shows FIG. 2 (c), FIG. 3 (c) and FIG.
It is a figure which shows the state which put together (b) and shows the combination of a radial bearing part and an axial bearing part. In the axial bearing 30 of FIG. 5, since the rotating body is eccentric vertically downward, the fixed permanent magnet 16 pushes the rotating permanent magnet 14 downward in the vertical direction, so-called radial direction. The unstable force R3u of (3) acts on the permanent magnet 15 on the rotating side, and the unstable force R4u of the radial direction from the permanent magnet 18 on the fixed side similarly acts.

In the radial bearing 29 of FIG. 5, the rotor is displaced in the direction of the impeller 22, so that the permanent magnet 10 on the fixed side is rotated to the permanent magnet 7 on the rotating side to the end of the impeller 22. An instability force A2u in the so-called axial direction, which pushes in the direction of, acts. Similarly, in the radial bearing 28 of FIG. 5, also for the permanent magnet 1 on the rotating side,
Unstable force A in the axial direction from the permanent magnet 4 on the fixed side
1u acts. Here, the condition that the rotating body is stable and can maintain the non-contact state with the fixed side is that these forces and these moments are balanced. The size of the permanent magnet shall satisfy these conditions. In FIG. 5, even when the axial load Ta is applied in the opposite direction to the impeller 22, the same condition may be satisfied.

Next, from the state shown in FIG. 5, a state in which the rotating body is rotated with a slight inclination with respect to the fixed side will be described.
As an example, FIG. 6 shows a state in which the rotating body is vertically upward with respect to the fixed side, and the impeller side is vertically downward with respect to the fixed side. In the axial bearing 30 shown in FIG. 6, the rotor is eccentric vertically downward and the lower side of the disk 13 is inclined toward the impeller 22 side. 14
The repulsive force in the axial direction with respect to A becomes larger toward the lower side than the upper side, and the repulsive force of the upper half of the disk 13 is T3a1 and the lower half is T3a2.

Similarly, the repulsive force in the axial direction from the permanent magnet 18 on the fixed side to the permanent magnet 15 on the rotating side becomes smaller as it goes downward rather than upward, and the repulsive force of the upper half of the disk 13 is reduced. Let T4a1 and the lower half be T4a2. In the radial bearing 29 of FIG. 6,
Since the rotor is displaced in the direction of the impeller 22 and the lower side on the side opposite to the impeller is lowered vertically downward, the permanent magnet 10 on the fixed side has a radial direction with respect to the permanent magnet 7 on the rotating side. The repulsive force in the upward direction on the side opposite to the impeller is larger than the upward force on the side adjacent to the impeller, which is divided in half in the horizontal direction, and the repulsive force in the half on the impeller side is R2s1 and the rest is R2s2. Similarly, also in the radial bearing 28 of FIG. 6, the repulsive forces R1s1 and R1s2 act. Here, the condition that the rotating body can be stably maintained in the non-contact state with the fixed side is that these forces and these moments are balanced.

The size of the permanent magnet should finally satisfy all of the conditions shown in FIG. 5, these conditions, and static conditions at the time of stop.

[0027]

As described above, according to the present invention, both the radial bearing and the axial bearing are configured to utilize the repulsive force of the permanent magnet, so that the rotating body is not in contact with the fixed side. The excellent effect that it can maintain and completely eliminate the wear of the bearing, maintain the purity of the liquid handled by the canned motor pump, and dramatically improve the service life, and can provide a highly reliable canned motor pump. Is obtained.

[Brief description of drawings]

FIG. 1 is a cross-sectional view showing a structure of a canned motor pump of the present invention.

FIG. 2 is a view showing a radial bearing portion of a canned motor pump of the present invention, FIGS. 2 (a) and 2 (c) are sectional views, and FIGS. 2 (b) and 2 (d) are FIGS. 2 (a) and 2 (a), respectively. It is sectional drawing which looked at (c) from the direction of the suction opening.

FIG. 3 is a view showing a radial bearing portion of a canned motor pump according to the present invention, FIGS. 3 (a) and 3 (c) are sectional views, and FIGS. 3 (b) and 3 (d) are FIG. 3 (a) and FIG. It is sectional drawing which looked at (c) from the direction of a suction port in the axial direction.

4A and 4B are views showing a portion of an axial bearing of the canned motor pump of the present invention.

FIG. 5 is a view showing a combination of a radial bearing portion and an axial bearing portion of the canned motor pump of the present invention.

FIG. 6 is a view showing a combination of a radial bearing portion and an axial bearing portion of the canned motor pump of the present invention.

FIG. 7 is a sectional view showing a structure of a conventional canned motor pump.

[Explanation of reference numerals] 1 permanent magnet 2 yoke 3 adapter 4 permanent magnet 5 yoke 6 cover 7 permanent magnet 8 yoke 9 adapter 10 permanent magnet 11 yoke 12 cover 13 disk 14 permanent magnet 15 permanent magnet 16 permanent magnet 17 yoke 18 permanent magnet 19 Yoke 20 Cover 21 End cover 22 Impeller 23 Main shaft 24 Rotor 25 Stator 26 Suction port 27 Discharge port 28 Radial bearing 29 Radial bearing 30 Axial bearing (thrust bearing)

Claims (1)

[Claims] 1. A canned motor pump in which one set of radial bearings are arranged on the impeller side and the opposite impeller side of a rotor and a stator of a canned motor, respectively, and an axial bearing is arranged at an arbitrary position of a main shaft. In each of the radial bearings on the vehicle side and the non-impeller side, one or a set of hollow-cylindrical permanent magnets is fitted to the outer periphery of a hollow-cylindrical rotation-side yoke on the rotation side, and the permanent magnets are fitted. The rotary side yoke is incorporated into the main shaft through an adapter, and a small radial gap is provided between the permanent magnet on the fixed side and the outer circumferential surface of the permanent magnet on the fixed side on the fixed side with respect to these permanent magnets. One or a set of hollow-cylindrical permanent magnets are fitted, these are assembled and fixed in a cover, and the permanent magnet on the rotating side and the permanent magnet on the stationary side repel each other in the radial direction. Is a structure, wherein the thrust bearing is mounted on the main shaft rotation side 1
One or a set of hollow-cylindrical permanent magnets are installed on both side surfaces of one disk or one side surface of each of two disks, and fixed on the fixed side so as to face each surface of those permanent magnets. One or a pair of hollow-cylindrical permanent magnets fitted in the side yokes are fixed in the cover with a small axial gap in the axial direction. The permanent magnets on the rotating side and the permanent magnets on the fixed side are fixed. Is a canned motor pump having a structure in which they repel each other in the axial direction.