CN113738657B

CN113738657B - Rare earth permanent magnet motor driven centrifugal pump and self-lubricating method

Info

Publication number: CN113738657B
Application number: CN202111292392.XA
Authority: CN
Inventors: 魏清希; 高丙文; 王辉; 程蕾
Original assignee: Xi'an Pump & Valve General Factory Co ltd
Current assignee: Xi'an Pump & Valve General Factory Co ltd
Priority date: 2021-11-03
Filing date: 2021-11-03
Publication date: 2022-03-15
Anticipated expiration: 2041-11-03
Also published as: CN113738657A

Abstract

The application discloses a rare earth permanent magnet motor driven centrifugal pump and a self-lubricating method, and belongs to the field of centrifugal pumps. An upper shaft sleeve, an upper rotor and a lower shaft sleeve are sequentially sleeved on the centrifugal pump, then an impeller is fixed at the top end of a main shaft through an impeller nut, and the back of the impeller is provided with an inwards concave mounting cavity; the upper shaft sleeve is sleeved with an upper bearing, and the upper magnetic steel is clamped in a placing cavity on the upper rotor; a lower bearing is sleeved outside the lower shaft sleeve; the outer edge of the lower bearing is firstly sleeved with the motor stator and then sleeved with the lower magnetic steel in the self axial direction, and the lower magnetic steel is clamped in the mounting cavity; the main shaft, the upper shaft sleeve, the lower shaft sleeve, the upper bearing, the upper rotor, the upper magnetic steel, the lower magnetic steel, the motor stator, the impeller and the impeller nut are all positioned in a placing inner cavity formed by the pump body, the pump cover and the end cover; the main shaft is provided with a balance through hole, the top end of the impeller nut is provided with a through hole, and the through hole and the balance through hole are coaxial so that the inlet of the pump body is communicated with the top end of the balance through hole. This application structure is light, can carry out the self-lubricating.

Description

Rare earth permanent magnet motor driven centrifugal pump and self-lubricating method

Technical Field

The application relates to the technical field of centrifugal pumps, in particular to a rare earth permanent magnet motor driven centrifugal pump and a self-lubricating method.

Background

Centrifugal pumps operate by causing centrifugal motion of a liquid medium by rotation of an impeller. The basic structure of the centrifugal pump is composed of an impeller, a pump body, a pump shaft, a bearing, a sealing ring, a stuffing box and the like. The existing centrifugal pump is driven by a motor, specifically, a motor shaft of the motor is connected with a pump shaft of the centrifugal pump through a coupler and a bearing box, and the motor works to drive the centrifugal pump to work.

The existing centrifugal pump and a mechanism for driving the centrifugal pump to work are large in structural size and low in safety and reliability due to the fact that auxiliary parts such as a rolling bearing and a mechanical seal are used, the use requirements cannot be met in application occasions with limited structural sizes, and meanwhile, the bearing needs external force for lubrication and extra workload can be increased.

Disclosure of Invention

The embodiment of the application provides a rare earth permanent magnet motor driven centrifugal pump and a self-lubricating method, and can solve the problems that the existing centrifugal pump and a driving part thereof are large in structural size, low in safety and reliability and incapable of meeting use requirements in application occasions with limited structural sizes, and extra workload can be increased due to the lubrication of bearings.

In a first aspect, an embodiment of the present invention provides a rare earth permanent magnet motor-driven centrifugal pump, including a centrifugal pump main body and a motor main body; the centrifugal pump main body comprises a pump body, an impeller nut, a pump cover, an end cover, a main shaft, an upper shaft sleeve, an upper bearing, a lower shaft sleeve and a lower bearing; the motor main body comprises lower magnetic steel, a motor stator, upper magnetic steel and an upper rotor; the main shaft is sequentially sleeved with an upper shaft sleeve, an upper rotor and a lower shaft sleeve along the direction from the tail end to the top end of the main shaft, the impeller is fixed at the top end of the main shaft through an impeller nut, and the back of the impeller is provided with an inwards concave mounting cavity; the upper bearing is sleeved outside the upper shaft sleeve, and the upper magnetic steel is clamped in the placing cavity on the upper rotor; the lower bearing is sleeved outside the lower shaft sleeve; the motor stator is sleeved outside the lower bearing along the axial direction of the lower bearing, then the lower magnetic steel is sleeved outside the lower bearing, and the lower magnetic steel is clamped in the installation cavity; the first end face of the pump cover is connected with the end face of the pump body, which is far away from the inlet of the pump cover, and the second end face of the pump cover is connected with the end face of the end cover, so that the pump body, the pump cover and the inner cavity of the end cover are combined into a placing inner cavity; the main shaft, the upper shaft sleeve, the upper bearing, the upper rotor, the upper magnetic steel, the lower shaft sleeve, the lower bearing, the motor stator, the lower magnetic steel, the impeller and the impeller nut are all positioned in the placement inner cavity, the outer wall of the upper bearing props against the inner wall of the end cover and the inner wall of the pump cover, and the outer wall of the motor stator and the outer wall of the first end of the impeller prop against the inner wall of the pump body; the main shaft is provided with a balance through hole along the self axial direction, the top end of the impeller nut is provided with a through hole, and when the impeller nut is installed on the top end of the main shaft, the through hole is coaxial with the balance through hole so that the inlet of the pump body is communicated with the top end of the balance through hole.

With reference to the first aspect, in one possible implementation manner, the upper bearing and/or the lower bearing is a sliding bearing.

With reference to the first aspect, in one possible implementation manner, the impeller, the lower shaft sleeve, and the upper rotor are all connected with the main shaft through keys.

With reference to the first aspect, in a possible implementation manner, a sealing ring is disposed at a joint of the first end surface of the pump cover and an end surface of the pump body, the joint being away from the inlet of the pump cover, and/or a sealing ring is disposed at a joint of the second end surface of the pump cover and an end surface of the end cover.

With reference to the first aspect, in one possible implementation manner, a cross section of the main shaft, taken by a plane passing through an axis of the main shaft, is T-shaped.

With reference to the first aspect, in a possible implementation manner, the centrifugal pump driven by the rare earth permanent magnet motor further includes a blocking piece, a liquid guiding pipeline, and a liquid guiding hole arranged on a side wall of the outlet section of the pump body; a through hole is formed in the bottom surface of the end cover, and a through hole is formed in the hub between the adjacent blades of the impeller along the axial direction of the hub; one end of the liquid leading pipeline is communicated with the liquid leading hole, the other end of the liquid leading pipeline is communicated with the through hole, and the plugging piece is plugged at the tail end of the balance through hole, so that the medium conveyed from the liquid leading pipeline flows in along a gap between the inner bottom wall of the end cover and the end face of the tail end of the main shaft, and finally flows out from the through hole to the inlet of the pump body.

With reference to the first aspect, in a possible implementation manner, the centrifugal pump driven by the rare earth permanent magnet motor further includes a blocking piece, a liquid guiding pipeline, and a liquid guiding hole arranged on a side wall of the outlet section of the pump body; a through hole is formed in the bottom surface of the end cover, one end of the liquid leading pipeline is communicated with the liquid leading hole, and the other end of the liquid leading pipeline is communicated with the through hole; the blocking piece blocks the tail end of the balance through hole so that the medium conveyed from the liquid guide pipeline flows in along a gap between the inner bottom wall of the end cover and the end face of the tail end of the main shaft; the hub of the upper rotor is provided with a radial hole which is through along the radial direction, and a through transverse hole is arranged at the position of the main shaft corresponding to the radial hole, so that a gap between the inner wall of the pump cover and the outer wall of the upper rotor is communicated with the balance through hole through the radial hole and the transverse hole, and a medium in the gap between the inner wall of the pump cover and the outer wall of the upper rotor can flow into the balance through hole.

In a second aspect, an embodiment of the present invention provides a self-lubricating method for a centrifugal pump driven by a rare earth permanent magnet motor, where the centrifugal pump driven by the rare earth permanent magnet motor includes: the medium delivered by the centrifugal pump flows into a gap between the inner wall of the pump body and the outer wall of the impeller from the outlet of the pump body, then flows into a gap between the upper end face of the lower magnetic steel and the lower end face of the motor stator, then flows into a gap between the inner wall of the lower magnetic steel and the outer wall of the lower bearing, then flows into a gap between the back end face of the impeller and the lower end face of the lower bearing, and finally flows into a gap between the inner wall of the lower bearing and the outer wall of the lower shaft sleeve, so that the self-lubrication of the lower bearing is completed; the medium conveyed by the centrifugal pump continuously flows into a gap between the upper end face of the motor stator and the lower end face of the upper magnetic steel, then flows into a gap between the inner wall of the pump body and the outer wall of the upper rotor, then flows into a gap between the upper end face of the upper rotor and the first end face of the pump cover, then flows into a gap between the inner wall of the pump cover and the upper shaft sleeve and a gap between the inner wall of the upper bearing and the outer wall of the upper shaft sleeve, namely, self-lubrication of the upper bearing is realized, then flows into a gap between the upper shaft sleeve, the outer wall at the tail end of the main shaft and the inner wall of the end cover, and finally flows into the inlet of the pump body and flows out after flowing into the gap between the end face at the tail end of the main shaft and the inner bottom wall of the end cover and flowing into the balance through hole.

In a third aspect, another embodiment of the present invention provides a self-lubricating method for a centrifugal pump driven by a rare-earth permanent magnet motor, where the centrifugal pump driven by the rare-earth permanent magnet motor includes: the medium delivered by the centrifugal pump flows into the liquid guiding hole from the outlet of the pump body, then flows into the liquid guiding pipeline, then flows into the through hole on the end cover, then flows into the gap between the end face of the tail end of the main shaft and the inner bottom wall of the end cover, then flows into the upper shaft sleeve, the gap between the outer wall of the tail end of the main shaft and the inner wall of the end cover, and finally flows into the gap between the inner wall of the upper bearing and the outer wall of the upper shaft sleeve, so that the self-lubrication of the upper bearing is completed; the medium conveyed by the centrifugal pump continuously flows into the gap between the inner wall of the pump cover and the upper shaft sleeve and the gap between the outer walls of the upper rotor and then flows into the gap between the first end face of the pump cover and the upper end face of the upper rotor, then flows into the gap between the inner wall of the pump body and the outer wall of the upper rotor and then flows into the gap between the upper end face of the motor stator and the lower end face of the upper magnetic steel, then flows into the gap between the inner wall of the lower bearing and the outer wall of the lower shaft sleeve, namely, self-lubrication of the lower bearing is realized, then flows into the gap between the lower end face of the lower bearing and the back end face of the impeller, and finally flows into the inlet of the pump body and flows out after flowing into the through hole arranged on the hub between the adjacent blades of the impeller along the axial direction of the hub.

In a fourth aspect, another embodiment of the present invention provides a self-lubricating method for a centrifugal pump driven by a rare-earth permanent magnet motor, where the centrifugal pump driven by the rare-earth permanent magnet motor includes: the medium delivered by the centrifugal pump flows into the liquid guiding hole from the outlet of the pump body, then flows into the liquid guiding pipeline, then flows into the through hole on the end cover, then flows into the gap between the end face of the tail end of the main shaft and the inner bottom wall of the end cover, then flows into the gap between the inner wall of the upper bearing and the outer wall of the upper shaft sleeve, namely completes the self-lubrication of the upper bearing, then flows into the gap between the inner wall of the pump cover and the outer walls of the upper shaft sleeve and the upper rotor, then flows into the radial hole on the upper rotor and the transverse hole on the main shaft, and finally flows into the inlet of the pump body and flows out after flowing into the balance through hole; meanwhile, the medium delivered by the centrifugal pump flows into the gap between the inner wall of the pump body and the outer wall of the impeller from the outlet of the pump body and then flows into the gap between the upper end face of the lower magnetic steel and the lower end face of the motor stator, then flows into a gap between the inner wall of the lower magnetic steel and the outer wall of the lower bearing, then flows into a gap between the back end surface of the impeller and the lower end surface of the lower bearing, and then flows into a gap between the inner wall of the lower bearing and the outer wall of the lower shaft sleeve, the self-lubricating of the lower bearing is completed, then the fluid flows into the gap between the upper end face of the motor stator and the lower end face of the upper magnetic steel, then flows into the gap between the inner wall of the pump body and the outer wall of the upper rotor, then flows into the gap between the upper end face of the upper rotor and the first end face of the pump cover, then flows into the radial hole on the upper rotor and the transverse hole on the main shaft, and finally flows into the inlet of the pump body and flows out after flowing into the balance through hole.

One or more technical solutions provided in the embodiments of the present invention have at least the following technical effects or advantages:

the embodiment of the invention provides a rare earth permanent magnet motor driven centrifugal pump which comprises a centrifugal pump main body and a motor main body. The centrifugal pump main body comprises a pump body, an impeller nut, a pump cover, an end cover, a main shaft, an upper shaft sleeve, an upper bearing, a lower shaft sleeve and a lower bearing. The motor main body comprises lower magnetic steel, a motor stator, upper magnetic steel and an upper rotor. The main shaft is sleeved with an upper shaft sleeve, an upper rotor and a lower shaft sleeve in sequence along the direction from the tail end of the main shaft to the top end, then the impeller is fixed at the top end of the main shaft through an impeller nut, and the back of the impeller is provided with an inwards concave installation cavity. The upper shaft sleeve is sleeved with an upper bearing, and the upper magnetic steel is clamped in the placing cavity on the upper rotor. The lower bearing is sleeved outside the lower shaft sleeve. The outer edge of the lower bearing is firstly sleeved with the motor stator along the self axial direction and then sleeved with the lower magnetic steel, and the lower magnetic steel is clamped in the installation cavity. The first end face of the pump cover is connected with the end face, deviating from the inlet, of the pump body, and the second end face of the pump cover is connected with the end face of the end cover, so that the pump body, the pump cover and the inner cavity of the end cover are combined into a placement inner cavity. The main shaft, the upper shaft sleeve, the upper bearing, the upper rotor, the upper magnetic steel, the lower shaft sleeve, the lower bearing, the motor stator, the lower magnetic steel, the impeller and the impeller nut are all located in the placement inner cavity, the outer wall of the upper bearing abuts against the inner wall of the end cover and the inner wall of the pump cover, and the outer wall of the motor stator and the outer wall of the first end of the impeller abut against the inner wall of the pump body. The utility model provides a centrifugal pump, centrifugal pump main part and motor main part pass through foretell installation and structural design, the function of centrifugal pump and motor has been realized simultaneously, encapsulate whole tombarthite permanent-magnet machine inside the pump body, this motor need not to take the shell certainly, the medium that the centrifugal pump carried can directly cool off this motor, and make centrifugal pump axial compact structure, reduce the holistic weight of centrifugal pump by a wide margin, make its structure portably, the suitability of centrifugal pump in the application occasion that the structural dimension is limited has been improved, and the reliability of centrifugal pump has been improved. In addition, the medium of the centrifugal pump of this application leaks not go out to need not sealed leak protection, and then cancelled auxiliary members such as the mechanical seal of current centrifugal pump and the mechanism of its work of drive, also further reduced the holistic structural dimension of centrifugal pump of this application, fail safe nature further increases, and reduced the cost of manufacture. Simultaneously, the mechanism of its work of current centrifugal pump and drive, need additionally to increase manpower and materials and lubricate the bearing, but the main shaft of the centrifugal pump of this application is provided with balanced through-hole along self axial, the top of impeller nut is provided with the via hole, when impeller nut installs in the top of main shaft, via hole and balanced through-hole are coaxial, so that the import of the pump body and the top intercommunication of balanced through-hole, balanced through-hole's setting, make things convenient for the circulation of medium, thereby the centrifugal pump is whole because self special structural design, can realize through the self-lubricating and the cooling of the medium of self transport to the centrifugal pump inner bearing, thereby extra work load has greatly been reduced, and can prevent the play of main shaft and the part of cover on the main shaft.

Drawings

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings needed to be used in the description of the embodiments of the present invention or the prior art will be briefly introduced below, and it is obvious that the drawings in the following description are some embodiments of the present invention, and for those skilled in the art, other drawings can be obtained according to these drawings without creative efforts.

Fig. 1 is a schematic structural diagram of a centrifugal pump driven by a rare-earth permanent magnet motor according to an embodiment of the present disclosure;

FIG. 2 is a self-lubricating schematic diagram of a rare earth permanent magnet motor driven centrifugal pump provided by an embodiment of the present application;

FIG. 3 is a self-lubricating schematic diagram of a rare earth permanent magnet motor driven centrifugal pump provided in another embodiment of the present application;

FIG. 4 is a self-lubricating schematic diagram of a rare earth permanent magnet motor driven centrifugal pump provided in accordance with yet another embodiment of the present application;

FIG. 5 is a schematic structural diagram of an upper bushing provided in an embodiment of the present application;

FIG. 6 is a schematic structural diagram of a centrifugal pump and a mechanism for driving the centrifugal pump to work in the prior art provided by an embodiment of the application;

fig. 7 is a schematic structural diagram of another prior art centrifugal pump and a mechanism for driving the centrifugal pump to work according to an embodiment of the present application.

Icon: 1-a centrifugal pump body; 10-a pump body; 101-an inlet; 102-an outlet; 103-a drainage hole; 11-an impeller; 111-a through-hole; 12-impeller nut; 121-via holes; 13-pump cover; 14-an end cap; 141-a through hole; 15-a main shaft; 151-balance vias; 152-a keyway; 153-cross holes; 16-an upper shaft sleeve; 161-spiral groove; 17-an upper bearing; 18-a lower shaft sleeve; 19-a lower bearing; 2-a motor body; 21-lower magnetic steel; 22-a motor stator; 23-upper magnetic steel; 24-an upper rotor; 241-radial holes; 3-sealing ring; 4-a liquid leading pipeline; 5-a bearing housing; 6-a coupler; 7-a motor; 8-plugging piece.

Detailed Description

The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are some, not all, embodiments of the present invention. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

In the description of the embodiments of the present invention, it should be noted that the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the drawings, and are only for convenience in describing the embodiments of the present invention and simplifying the description, but do not indicate or imply that the referred devices or elements must have specific orientations, be configured in specific orientations, and operate, and thus, should not be construed as limiting the present invention. The terms "first," "second," and "third" are used for descriptive purposes only and are not to be construed as indicating or implying relative importance. Furthermore, the terms "mounted," "connected," and "connected" are to be construed broadly and may, for example, be fixedly connected, detachably connected, or integrally connected; can be mechanically or electrically connected; they may be connected directly or indirectly through intervening media, or they may be interconnected between two elements. Specific meanings of the above terms in the embodiments of the present invention can be understood by those of ordinary skill in the art according to specific situations.

Centrifugal pumps operate by centrifugal motion of a liquid medium as a result of rotation of an impeller 11. The basic structure of the centrifugal pump is composed of an impeller 11, a pump body 10, a pump shaft, a bearing, a sealing ring, a stuffing box and the like. As shown in fig. 6 and 7, the existing centrifugal pump is driven by a motor 7, specifically, a motor shaft of the motor 7 is connected to a pump shaft of the centrifugal pump through a coupling 6 and a bearing box 5, and the motor 7 operates to drive the centrifugal pump to operate. In which fig. 6 shows a schematic configuration in which the axis of the inlet 101 and the axis of the outlet 102 of the centrifugal pump are perpendicular to each other, and fig. 7 shows a schematic configuration in which the axis of the inlet 101 and the axis of the outlet 102 of the centrifugal pump are parallel to each other.

The existing centrifugal pump and the structure for driving the centrifugal pump to work are large in structural size and low in safety and reliability due to the fact that auxiliary parts such as a rolling bearing and a mechanical seal are used, the use requirements cannot be met in application occasions with limited structural sizes, and meanwhile, the bearing needs external force for lubrication and extra workload can be increased.

Referring to fig. 1 to 4, an embodiment of the present invention provides a rare earth permanent magnet motor driven centrifugal pump, including a centrifugal pump main body 1 and a motor main body 2.

The centrifugal pump main body 1 comprises a pump body 10, an impeller 11, an impeller nut 12, a pump cover 13, an end cover 14, a main shaft 15, an upper shaft sleeve 16, an upper bearing 17, a lower shaft sleeve 18 and a lower bearing 19. The motor main body 2 comprises a lower magnetic steel 21, a motor stator 22, an upper magnetic steel 23 and an upper rotor 24. Wherein, impeller 11 still plays the effect of rotor under the motor in the centrifugal pump of this application to rotor universalization under making impeller 11 and the motor, when can making motor 7 normally work and drive centrifugal pump work, still practiced thrift motor 7's part, and then reduced the whole space size of the centrifugal pump of this application and reduced its cost.

The main shaft 15 is sequentially sleeved with an upper shaft sleeve 16, an upper rotor 24 and a lower shaft sleeve 18 along the direction from the tail end of the main shaft 15 to the top end (as shown in fig. 1-4, the upper end of the main shaft 15 is the tail end, and the lower end of the main shaft 15 is the top end), then the impeller 11 is fixed at the top end of the main shaft 15 through an impeller nut 12, and the back of the impeller 11 is provided with a concave mounting chamber. The main shaft 15 of this application both had been regarded as the pump shaft of centrifugal pump main part 1, also regarded as motor main part 2's motor shaft, and a dual-purpose can realize centrifugal pump main part 1 and motor main part 2's function simultaneously, can make the centrifugal pump structure size of this application reduce moreover, more portably to reduce manufacturing cost.

An upper bearing 17 is sleeved outside the upper shaft sleeve 16, and an upper magnetic steel 23 is clamped in a placing cavity on the upper rotor 24, namely the upper magnetic steel 23 is embedded in the upper rotor 24. The lower bearing 19 is sleeved outside the lower shaft sleeve 18. The outer edge of the lower bearing 19 is firstly sleeved with a motor stator 22 along the axial direction of the lower bearing, then the lower magnetic steel 21 is sleeved with the lower magnetic steel 21, and the lower magnetic steel 21 is clamped in the installation cavity, namely the lower magnetic steel 21 is embedded on the back of the impeller 11.

The first end face of the pump cover 13 is connected with the end face of the pump body 10, which is far away from the inlet 101, and the second end face of the pump cover 13 is connected with the end face of the end cover 14, so that the inner cavities of the pump body 10, the pump cover 13 and the end cover 14 are combined into a holding inner cavity. As shown in fig. 1 to 4, the first end surface of the pump cover 13 refers to the lower end surface of the pump cover 13, and the second end surface refers to the upper end surface of the pump cover 13.

The main shaft 15, the upper shaft sleeve 16, the upper bearing 17, the upper rotor 24, the upper magnetic steel 23, the lower shaft sleeve 18, the lower bearing 19, the motor stator 22, the lower magnetic steel 21, the impeller 11 and the impeller nut 12 are all located in the placement inner cavity, and the outer wall of the upper bearing 17 abuts against the inner wall of the end cover 14 and the inner wall of the pump cover 13. The outer wall of the motor stator 22 and the outer wall of the first end of the impeller 11 (the lower end of the impeller 11 in fig. 1) both abut against the inner wall of the pump body 10. Namely, the motor stator 22 is directly mounted on the pump body 10 in an embedded manner, so that the pump body 10 and the motor stator 22 are integrated.

The main shaft 15 is provided with a balance through hole 151 along its own axial direction, that is, a hole which is formed in the main shaft 15 along its own axial direction and is completely penetrated is the balance through hole 151. The top end of the impeller nut 12 is provided with a through hole 121, and when the impeller nut 12 is mounted on the top end of the main shaft 15, the through hole 121 and the balance through hole 151 are coaxial, so that the inlet 101 of the pump body 10 communicates with the top end of the balance through hole 151. In the working process, a medium flows in from the inlet 101 of the pump body 10, the medium is high in pressure and impacts on the main shaft 15, so that the main shaft 15 and a component sleeved on the main shaft 15 can move in the direction away from the inlet 101, and the balance through hole 151 is arranged, so that the high-pressure medium input from the tail end of the main shaft 15 can provide a counteracting force opposite to the impact force generated by the medium flowing in from the inlet 101 of the pump body 10, and the main shaft 15 and the component sleeved on the main shaft 15 can be prevented from moving.

The embodiment of the invention provides a rare earth permanent magnet motor driven centrifugal pump which comprises a centrifugal pump main body 1 and a motor main body 2. The centrifugal pump main body 1 comprises a pump body 10, an impeller 11, an impeller nut 12, a pump cover 13, an end cover 14, a main shaft 15, an upper shaft sleeve 16, an upper bearing 17, a lower shaft sleeve 18 and a lower bearing 19. The motor main body 2 comprises a lower magnetic steel 21, a motor stator 22, an upper magnetic steel 23 and an upper rotor 24. The main shaft 15 is sleeved with an upper shaft sleeve 16, an upper rotor 24 and a lower shaft sleeve 18 in sequence along the direction from the tail end of the main shaft to the top end, then the impeller 11 is fixed at the top end of the main shaft 15 through an impeller nut 12, and the back of the impeller 11 is provided with a concave mounting chamber. An upper bearing 17 is sleeved outside the upper shaft sleeve 16, and an upper magnetic steel 23 is clamped in a placing cavity on the upper rotor 24. The lower bearing 19 is sleeved outside the lower shaft sleeve 18. The outer edge of the lower bearing 19 is firstly sleeved with a motor stator 22 along the self axial direction, then is sleeved with a lower magnetic steel 21, and the lower magnetic steel 21 is clamped in the installation cavity. The first end face of the pump cover 13 is connected with the end face of the pump body 10, which is far away from the inlet 101, and the second end face of the pump cover 13 is connected with the end face of the end cover 14, so that the inner cavities of the pump body 10, the pump cover 13 and the end cover 14 are combined into a holding inner cavity. The main shaft 15, the upper shaft sleeve 16, the upper bearing 17, the upper rotor 24, the upper magnetic steel 23, the lower shaft sleeve 18, the lower bearing 19, the motor stator 22, the lower magnetic steel 21, the impeller 11 and the impeller nut 12 are all located in the placement inner cavity, the outer wall of the upper bearing 17 abuts against the inner wall of the end cover 14 and the inner wall of the pump cover 13, and the outer wall of the motor stator 22 and the outer wall of the first end of the impeller 11 abut against the inner wall of the pump body 10. The utility model provides a centrifugal pump, centrifugal pump main part 1 and motor main part 2 are through foretell installation and structural design, the function of centrifugal pump and motor 7 has been realized simultaneously, encapsulate whole tombarthite permanent-magnet machine inside pump body 10, this motor need not to take the shell certainly, the medium that the centrifugal pump was carried can directly cool off this motor, and make centrifugal pump axial compact structure, reduce the holistic weight of centrifugal pump by a wide margin, make its structure light, the suitability of centrifugal pump in the application occasion that the structural dimension is limited has been improved, and the reliability of centrifugal pump has been improved. In addition, the medium of the centrifugal pump of this application leaks not go out to need not sealed leak protection, and then cancelled auxiliary members such as the mechanical seal of current centrifugal pump and the mechanism of its work of drive, also further reduced the holistic structural dimension of centrifugal pump of this application, fail safe nature further increases, and reduced the cost of manufacture. Meanwhile, the existing centrifugal pump and the mechanism for driving the centrifugal pump to work need to additionally increase manpower and material resources to lubricate the bearing, but the spindle 15 of the centrifugal pump of the application is provided with a balance through hole 151 along the self axial direction, the top end of the impeller nut 12 is provided with a through hole 121, when the impeller nut 12 is installed on the top end of the spindle 15, the through hole 121 and the balance through hole 151 are coaxial, so that the inlet 101 of the pump body 10 is communicated with the top end of the balance through hole 151, the setting of the balance through hole 151 is facilitated, the circulation of media is facilitated, the whole centrifugal pump is designed by the self special structure, the self-lubricating and cooling of the inner bearing of the centrifugal pump by the media conveyed by the self can be realized, the extra workload is greatly reduced, and the shifting of the spindle 15 and the part sleeved on the spindle 15 can be prevented.

In practice, the upper bearing 17 and/or the lower bearing 19 are sliding bearings. Specifically, the upper bearing 17 may be a slide bearing, the lower bearing 19 may be a slide bearing, or both the upper bearing 17 and the lower bearing 19 may be slide bearings. In practice, the medium delivered by the centrifugal pump is generally water, and the water has better lubricating effect on the sliding bearing.

Further, the impeller 11, the lower boss 18 and the upper rotor 24 are all connected to the main shaft 15 by keys. Specifically, as shown in fig. 1 to 4, the main shaft 15 is provided with a key groove 152, and the key groove 152 on the main shaft 15 cooperates with the key to connect the impeller 11, the lower shaft sleeve 18 and the upper rotor 24 with the main shaft 15.

With continued reference to fig. 1 to 4, a sealing ring 3 is disposed at a joint of a first end surface of the pump cover 13 and an end surface of the pump body 10 away from the inlet 101, and/or a sealing ring 3 is disposed at a joint of a second end surface of the pump cover 13 and an end surface of the end cover 14. Specifically, a sealing ring 3 may be disposed at a joint between a first end surface of the pump cover 13 and an end surface of the pump body 10 away from the inlet 101, a sealing ring 3 may be disposed at a joint between a second end surface of the pump cover 13 and an end surface of the end cover 14, and sealing rings 3 may be disposed at a joint between the first end surface of the pump cover 13 and the end surface of the pump body 10 away from the inlet 101 and a joint between the second end surface of the pump cover 13 and the end surface of the end cover 14. The utility model provides a tombarthite permanent-magnet machine drives centrifugal pump closes centrifugal pump main part 1 and motor main part 2 to same whole, has cancelled auxiliary members such as the mechanical seal (dynamic seal) of the mechanism of centrifugal pump and its drive work, and the setting of sealing washer 3, the terminal surface junction that deviates from self import 101 at the first terminal surface of pump cover 13 and the pump body 10 is provided with sealing washer 3, and/or, the second terminal surface of pump cover 13 sets up static seal with the terminal surface junction of end cover 14, can improve the holistic leakproofness of centrifugal pump of this application. Further, the seal ring 3 is an O-ring. The O-shaped sealing ring has the advantages of simple structure, small volume, self-sealing effect, no need of periodic adjustment, good sealing performance, no leakage during static sealing, standardized size and groove, easy obtaining of products, convenient use and purchase, strong adaptability and wide application.

As shown in fig. 1, the main shaft 15 has a T-shaped cross section sectioned by a plane passing through the axis thereof, so that when the upper bushing 16, the upper rotor 24, and the lower bushing 18 are sleeved on the main shaft 15, they can be prevented from slipping off from the end of the main shaft 15, thereby improving the safety of the centrifugal pump of the present application.

The working process of the rare earth permanent magnet motor driven centrifugal pump provided by the embodiment of the invention is as follows: when the motor main body 2 is powered on, the main shaft 15 drives the impeller 11 to rotate, the impeller 11 starts to work, and the medium flows in from the inlet 101 of the pump body 10 and is discharged from the outlet 102 of the pump body 10 after being acted by the centrifugal force of the impeller 11.

As shown in fig. 3, the centrifugal pump driven by the rare earth permanent magnet motor according to the embodiment of the present application further includes a blocking piece 8, a liquid guiding pipeline 4, and a liquid guiding hole 103 disposed on a side wall of the outlet section of the pump body 10. The plugging member 8 may be a plug or a plug. The bottom surface of the end cover 14 is provided with a through hole 141, and a through hole 111 is provided in the hub between adjacent blades of the impeller 11 in the axial direction thereof. One end of the liquid leading pipeline 4 is communicated with the liquid leading hole 103, the other end is communicated with the through hole 141, and the blocking piece 8 blocks the tail end of the balance through hole 151, so that the medium conveyed from the liquid leading pipeline 4 flows in along the gap between the inner bottom wall of the end cover 14 and the end face of the tail end of the main shaft 15, and finally flows out from the through hole 111 to the inlet 101 of the pump body 10.

As shown in fig. 3, the flow direction of the medium for self-lubricating the centrifugal pump driven by the rare-earth permanent magnet motor provided by the embodiment of the present application is: the medium delivered by the centrifugal pump flows into the liquid guiding hole 103 from the outlet 102 of the pump body 10, then flows into the liquid guiding pipeline 4, then flows into the through hole 141 on the end cover 14, then flows into the gap between the end face of the tail end of the main shaft 15 and the inner bottom wall of the end cover 14, then flows into the upper shaft sleeve 16, the gap between the outer wall of the tail end of the main shaft 15 and the inner wall of the end cover 14, and finally flows into the gap between the inner wall of the upper bearing 17 and the outer wall of the upper shaft sleeve 16, so that the self-lubrication of the upper bearing 17 and the cooling of the upper bearing 17 are completed. The medium delivered by the centrifugal pump continuously flows into the gap between the inner wall of the pump cover 13 and the outer walls of the upper shaft sleeve 16 and the upper rotor 24, then flows into the gap between the first end surface of the pump cover 13 and the upper end surface of the upper rotor 24, then flows into the gap between the inner wall of the pump body 10 and the outer wall of the upper rotor 24, then flows into the gap between the upper end surface of the motor stator 22 and the lower end surface of the upper magnetic steel 23, then flows into the gap between the inner wall of the lower bearing 19 and the outer wall of the lower shaft sleeve 18, namely, self-lubrication of the lower bearing 19 and cooling of the lower bearing 19 are realized, then flows into the gap between the lower end surface of the lower bearing 19 and the back end surface of the impeller 11, and finally flows into the inlet 101 of the pump body 10 and flows out after flowing into the through hole 111 arranged on the hub between the adjacent blades of the impeller 11 along the axial direction of the hub.

The liquid guide hole 103 and the liquid guide pipeline 4 are arranged, so that high-pressure medium can be conveniently introduced from the tail end of the main shaft 15. Generally, the pressure at the end of the main shaft 15 is high, the upper bearing 17 is located at a position where the inlet 101 of the pump body 10 introduces high-pressure medium through the liquid introduction pipeline 4, the pressure at the end of the inlet 101 of the pump body 10 is low, and the through hole 111 arranged on the hub between the adjacent blades of the impeller 11 along the axial direction of the upper bearing makes the lower end surface of the lower bearing 19 communicate with the low-pressure end of the inlet 101 of the pump body 10, so that a large high-low pressure difference is formed, and after the medium flows from the gap between the inner bottom wall of the end cover 14 and the end surface of the end of the main shaft 15, the medium flows through the upper bearing 17 and the lower bearing 19 and lubricates the medium, namely, the circulation of a self-lubricating circuit is facilitated. In addition, the through holes 111 provided in the hub between adjacent blades of the impeller 11 can balance the force applied between the front end surface and the back end surface of the impeller 11, that is, the force of the impeller 11 in the axial direction of the impeller 11, so that the force applied to the impeller 11 tends to be balanced.

As shown in fig. 4, the centrifugal pump driven by the rare earth permanent magnet motor provided by the embodiment of the present application further includes a blocking piece 8, a liquid guiding pipeline 4, and a liquid guiding hole 103 disposed on a side wall of the outlet section of the pump body 10. A through hole 141 is provided on the bottom surface of the end cap 14, and one end of the liquid guiding pipe 4 is communicated with the liquid guiding hole 103, and the other end is communicated with the through hole 141. The block piece 8 blocks the distal end of the balance through hole 151 to allow the medium fed from the liquid introduction line 4 to flow in along the gap between the inner bottom wall of the end cap 14 and the end face of the distal end of the main shaft 15. A radial hole 241 which penetrates in the radial direction is formed in the hub of the upper rotor 24, and a through transverse hole 153 is formed in the position, corresponding to the position of the radial hole 241, of the main shaft 15, so that a gap between the inner wall of the pump cover 13 and the outer wall of the upper rotor 24 is communicated with the balance through hole 151 through the radial hole 241 and the transverse hole 153, and a medium in the gap between the inner wall of the pump cover 13 and the outer wall of the upper rotor 24 can flow into the balance through hole 151.

As shown in fig. 4, the medium flow direction of the rare earth permanent magnet motor driving centrifugal pump provided in the embodiment of the present application for self-lubricating is as follows: the medium delivered by the centrifugal pump flows into the liquid guiding hole 103 from the outlet 102 of the pump body 10, then flows into the liquid guiding pipeline 4, then flows into the through hole 141 on the end cover 14, then flows into the gap between the end face of the end of the main shaft 15 and the inner bottom wall of the end cover 14, then flows into the gap between the upper shaft sleeve 16 and the outer wall of the end of the main shaft 15, then flows into the gap between the inner wall of the upper bearing 17 and the outer wall of the upper shaft sleeve 16, namely completes self-lubrication of the upper bearing 17 and cooling of the upper bearing 17, then flows into the gap between the inner wall of the pump cover 13 and the outer walls of the upper shaft sleeve 16 and the upper rotor 24, then flows into the radial hole 241 on the upper rotor 24 and the transverse hole 153 on the main shaft 15, and finally flows into the balance through hole 151, then flows into the inlet 101 of the pump body 10 and flows out. Meanwhile, the medium delivered by the centrifugal pump flows into the gap between the inner wall of the pump body 10 and the outer wall of the impeller 11 from the outlet 102 of the pump body 10, then flows into the gap between the upper end surface of the lower magnetic steel 21 and the lower end surface of the motor stator 22, then flows into the gap between the inner wall of the lower magnetic steel 21 and the outer wall of the lower bearing 19, then flows into the gap between the back end surface of the impeller 11 and the lower end surface of the lower bearing 19, then flows into the gap between the inner wall of the lower bearing 19 and the outer wall of the lower shaft sleeve 18, namely, completes the self-lubrication of the lower bearing 19 and the cooling of the lower bearing 19, then flows into the gap between the upper end surface of the motor stator 22 and the lower end surface of the upper magnetic steel 23, then flows into the gap between the inner wall of the pump body 10 and the outer wall of the upper rotor 24, then flows into the gap between the upper end surface of the upper rotor 24 and the first end surface of the pump cover 13, and then flows into the radial hole 241 on the main shaft 15 and the transverse hole 153, finally flows into the balance through hole 151 and then flows into the inlet 101 of the pump body 10 and flows out.

The position of the transverse hole 153 on the main shaft 15 is a high-pressure end, and the medium flows in from the liquid guiding pipeline 4 and flows through the upper bearing 17, and the medium directly flows in from the outlet 102 of the pump body 10 and flows through the lower bearing 19, finally flows into the middle of the balance through hole 151 through the radial hole 241 on the upper rotor 24 and the transverse hole 153 on the main shaft 15, and then flows into the low-pressure end of the inlet 101 of the pump body 10, so that the increase of the pressure difference between the high-pressure end and the low-pressure end is realized, the circulation of the self-lubricating medium is facilitated, and the main shaft 15 and the components sleeved on the main shaft 15 can be prevented from moving.

In practical application, the rare-earth permanent magnet motor of the above embodiment drives the centrifugal pump, and the axial direction of the inlet 101 and the axial direction of the outlet 102 of the centrifugal pump may be perpendicular to each other or parallel to each other.

The embodiment of the invention provides a self-lubricating method of a rare earth permanent magnet motor driven centrifugal pump, which is based on the rare earth permanent magnet motor driven centrifugal pump.

As shown in fig. 2, includes: the medium delivered by the centrifugal pump flows into the gap between the inner wall of the pump body 10 and the outer wall of the impeller 11 from the outlet 102 of the pump body 10, then flows into the gap between the upper end surface of the lower magnetic steel 21 and the lower end surface of the motor stator 22, then flows into the gap between the inner wall of the lower magnetic steel 21 and the outer wall of the lower bearing 19, then flows into the gap between the back end surface of the impeller 11 and the lower end surface of the lower bearing 19, and finally flows into the gap between the inner wall of the lower bearing 19 and the outer wall of the lower shaft sleeve 18, so that the self-lubrication of the lower bearing 19 is completed, and the lower bearing 19 can be cooled.

The medium delivered by the centrifugal pump continuously flows into the gap between the upper end face of the motor stator 22 and the lower end face of the upper magnetic steel 23, then flows into the gap between the inner wall of the pump body 10 and the outer wall of the upper rotor 24, then flows into the gap between the upper end face of the upper rotor 24 and the first end face of the pump cover 13, then flows into the gap between the inner wall of the pump cover 13 and the outer walls of the upper sleeve 16 and the upper rotor 24, then flows into the gap between the inner wall of the upper bearing 17 and the outer wall of the upper sleeve 16, namely, self-lubrication of the upper bearing 17 is realized, meanwhile, the upper bearing 17 can be cooled, flows into the gap between the outer wall of the tail end of the upper sleeve 16 and the inner wall of the end cover 14, finally flows into the gap between the end face of the tail end of the main shaft 15 and the inner bottom wall of the end cover 14, then flows into the balance through hole 151, and then flows into the inlet 101 of the pump body 10 and flows out.

As shown in fig. 5, the outer walls of the lower shaft sleeve 18 and the upper shaft sleeve 16 are provided with spiral grooves 161, and when a medium flows through the outer wall of the lower shaft sleeve 18 or the outer wall of the upper shaft sleeve 16, the outer walls of the lower shaft sleeve 18 and the upper shaft sleeve 16 can play a role of boosting pressure, so that the medium smoothly flows through the outer wall of the upper shaft sleeve 16 after flowing through the lower shaft sleeve 18, and further, the lower bearing 19 and the upper bearing 17 are well self-lubricated. By adopting the self-lubricating method of the embodiment of the application, the self-lubricating of the upper bearing 17 and the lower bearing 19 can be well carried out, the medium finally flows to the balance through hole 151, the main shaft 15 and all the parts sleeved on the main shaft can be prevented from moving simultaneously, and in addition, the medium can flow through all the parts of the motor main body 2 due to the circulation, so that the motor main body 2 can be cooled.

The invention further provides a self-lubricating method of the rare earth permanent magnet motor driven centrifugal pump, which is based on the rare earth permanent magnet motor driven centrifugal pump.

As shown in fig. 3, the method includes: the medium delivered by the centrifugal pump flows into the liquid guiding hole 103 from the outlet 102 of the pump body 10, then flows into the liquid guiding pipeline 4, then flows into the through hole 141 on the end cover 14, then flows into the gap between the end face of the tail end of the main shaft 15 and the inner bottom wall of the end cover 14, then flows into the upper shaft sleeve 16, the gap between the outer wall of the tail end of the main shaft 15 and the inner wall of the end cover 14, and finally flows into the gap between the inner wall of the upper bearing 17 and the outer wall of the upper shaft sleeve 16, so that the self-lubrication of the upper bearing 17 and the cooling of the upper bearing 17 are completed. The medium delivered by the centrifugal pump continuously flows into the gap between the inner wall of the pump cover 13 and the outer walls of the upper shaft sleeve 16 and the upper rotor 24, then flows into the gap between the first end surface of the pump cover 13 and the upper end surface of the upper rotor 24, then flows into the gap between the inner wall of the pump body 10 and the outer wall of the upper rotor 24, then flows into the gap between the upper end surface of the motor stator 22 and the lower end surface of the upper magnetic steel 23, then flows into the gap between the inner wall of the lower bearing 19 and the outer wall of the lower shaft sleeve 18, namely, self-lubrication of the lower bearing 19 and cooling of the lower bearing 19 are realized, then flows into the gap between the lower end surface of the lower bearing 19 and the back end surface of the impeller 11, and finally flows into the inlet 101 of the pump body 10 and flows out after flowing into the through hole 111 arranged on the hub between the adjacent blades of the impeller 11 along the axial direction of the hub. By adopting the self-lubricating method of the embodiment of the invention, because the tail end of the main shaft 15 is a high-pressure side and the inlet 101 of the pump body 10 is a low-pressure side, pressure difference can be formed, so that the medium can be well self-lubricated and cooled by the upper bearing 17 and the lower bearing 19, and in addition, the medium can flow through each part of the motor main body 2 due to circulation, so that the motor main body 2 can be cooled.

As shown in fig. 4, includes: the medium delivered by the centrifugal pump flows into the liquid guiding hole 103 from the outlet 102 of the pump body 10, then flows into the liquid guiding pipeline 4, then flows into the through hole 141 on the end cover 14, then flows into the gap between the end face of the end of the main shaft 15 and the inner bottom wall of the end cover 14, then flows into the gap between the upper shaft sleeve 16 and the outer wall of the end of the main shaft 15, then flows into the gap between the inner wall of the upper bearing 17 and the outer wall of the upper shaft sleeve 16, namely completes self-lubrication of the upper bearing 17 and cooling of the upper bearing 17, then flows into the gap between the inner wall of the pump cover 13 and the outer walls of the upper shaft sleeve 16 and the upper rotor 24, then flows into the radial hole 241 on the upper rotor 24 and the transverse hole 153 on the main shaft 15, and finally flows into the balance through hole 151, then flows into the inlet 101 of the pump body 10 and flows out. Meanwhile, the medium delivered by the centrifugal pump flows into the gap between the inner wall of the pump body 10 and the outer wall of the impeller 11 from the outlet 102 of the pump body 10, then flows into the gap between the upper end surface of the lower magnetic steel 21 and the lower end surface of the motor stator 22, then flows into the gap between the inner wall of the lower magnetic steel 21 and the outer wall of the lower bearing 19, then flows into the gap between the back end surface of the impeller 11 and the lower end surface of the lower bearing 19, then flows into the gap between the inner wall of the lower bearing 19 and the outer wall of the lower shaft sleeve 18, namely, completes the self-lubrication of the lower bearing 19 and the cooling of the lower bearing 19, then flows into the gap between the upper end surface of the motor stator 22 and the lower end surface of the upper magnetic steel 23, then flows into the gap between the inner wall of the pump body 10 and the outer wall of the upper rotor 24, then flows into the gap between the upper end surface of the upper rotor 24 and the first end surface of the pump cover 13, and then flows into the radial hole 241 on the main shaft 15 and the transverse hole 153, finally flows into the balance through hole 151 and then flows into the inlet 101 of the pump body 10 and flows out. By adopting the self-lubricating method of the embodiment of the invention, the medium flowing in from the liquid guide pipeline 4 can perform self-lubrication on the upper bearing 17 well, the medium directly flowing in from the outlet 102 of the pump body 10 can perform self-lubrication on the lower bearing 19, so that the self-lubrication of the upper bearing 17 and the lower bearing 19 can be performed at the same time, and in addition, the medium can flow through each part of the motor main body 2 due to circulation, so that the motor main body 2 can also be cooled.

The embodiments in the present specification are described in a progressive manner, and the same or similar parts among the embodiments may be referred to each other, and each embodiment focuses on the differences from the other embodiments.

The above embodiments are only used to illustrate the technical solutions of the present application, and not to limit the present application; although the present application has been described in detail with reference to the foregoing embodiments, it will be understood by those of ordinary skill in the art that: the technical solutions described in the foregoing embodiments may still be modified, or some or all of the technical features may be equivalently replaced; such modifications or substitutions do not depart from the spirit and scope of the present disclosure.

Claims

1. A rare earth permanent magnet motor driven centrifugal pump is characterized by comprising a centrifugal pump main body and a motor main body;

the centrifugal pump main body comprises a pump body, an impeller nut, a pump cover, an end cover, a main shaft, an upper shaft sleeve, an upper bearing, a lower shaft sleeve and a lower bearing; the motor main body comprises lower magnetic steel, a motor stator, upper magnetic steel and an upper rotor;

the main shaft is sequentially sleeved with an upper shaft sleeve, an upper rotor and a lower shaft sleeve along the direction from the tail end to the top end of the main shaft, the impeller is fixed at the top end of the main shaft through an impeller nut, and the back of the impeller is provided with an inwards concave mounting cavity;

the upper bearing is sleeved outside the upper shaft sleeve, and the upper magnetic steel is clamped in the placing cavity on the upper rotor; the lower bearing is sleeved outside the lower shaft sleeve; the motor stator is sleeved outside the lower bearing along the axial direction of the lower bearing, then the lower magnetic steel is sleeved outside the lower bearing, and the lower magnetic steel is clamped in the installation cavity;

the first end face of the pump cover is connected with the end face of the pump body, which is far away from the inlet of the pump cover, and the second end face of the pump cover is connected with the end face of the end cover, so that the pump body, the pump cover and the inner cavity of the end cover are combined into a placing inner cavity;

the main shaft, the upper shaft sleeve, the upper bearing, the upper rotor, the upper magnetic steel, the lower shaft sleeve, the lower bearing, the motor stator, the lower magnetic steel, the impeller and the impeller nut are all positioned in the placement inner cavity, the outer wall of the upper bearing props against the inner wall of the end cover and the inner wall of the pump cover, and the outer wall of the motor stator and the outer wall of the first end of the impeller prop against the inner wall of the pump body;

the main shaft is provided with a balance through hole along the self axial direction, the top end of the impeller nut is provided with a through hole, and when the impeller nut is arranged at the top end of the main shaft, the through hole and the balance through hole are coaxial so that the inlet of the pump body is communicated with the top end of the balance through hole;

the upper bearing and/or the lower bearing are sliding bearings.

2. The rare earth permanent magnet motor driven centrifugal pump of claim 1, wherein said impeller, said lower hub and said upper rotor are all connected to said main shaft by keys.

3. The centrifugal pump driven by the rare earth permanent magnet motor according to claim 1, wherein a sealing ring is arranged at a joint of the first end face of the pump cover and an end face of the pump body, which is far away from an inlet of the pump cover, and/or a sealing ring is arranged at a joint of the second end face of the pump cover and an end face of the end cover.

4. The rare earth permanent magnet motor-driven centrifugal pump of claim 1, wherein the section of the main shaft taken by a plane passing through the axis of the main shaft is T-shaped.

5. The rare earth permanent magnet motor-driven centrifugal pump of claim 1, further comprising a blocking piece, a liquid guiding pipeline and a liquid guiding hole arranged on the side wall of the outlet section of the pump body;

a through hole is formed in the bottom surface of the end cover, and a through hole is formed in the hub between the adjacent blades of the impeller along the axial direction of the hub;

one end of the liquid leading pipeline is communicated with the liquid leading hole, the other end of the liquid leading pipeline is communicated with the through hole, and the plugging piece is plugged at the tail end of the balance through hole, so that the medium conveyed from the liquid leading pipeline flows in along a gap between the inner bottom wall of the end cover and the end face of the tail end of the main shaft, and finally flows out from the through hole to the inlet of the pump body.

6. The rare earth permanent magnet motor-driven centrifugal pump of claim 1, further comprising a blocking piece, a liquid guiding pipeline and a liquid guiding hole arranged on the side wall of the outlet section of the pump body;

a through hole is formed in the bottom surface of the end cover, one end of the liquid leading pipeline is communicated with the liquid leading hole, and the other end of the liquid leading pipeline is communicated with the through hole;

the blocking piece blocks the tail end of the balance through hole so that the medium conveyed from the liquid guide pipeline flows in along a gap between the inner bottom wall of the end cover and the end face of the tail end of the main shaft;

the hub of the upper rotor is provided with a radial hole which is through along the radial direction, and a through transverse hole is arranged at the position of the main shaft corresponding to the radial hole, so that a gap between the inner wall of the pump cover and the outer wall of the upper rotor is communicated with the balance through hole through the radial hole and the transverse hole, and a medium in the gap between the inner wall of the pump cover and the outer wall of the upper rotor can flow into the balance through hole.

7. A self-lubricating method of a rare earth permanent magnet motor driven centrifugal pump, which is characterized in that the rare earth permanent magnet motor driven centrifugal pump based on any one of claims 1 to 4 comprises the following steps:

the medium delivered by the centrifugal pump flows into a gap between the inner wall of the pump body and the outer wall of the impeller from the outlet of the pump body, then flows into a gap between the upper end face of the lower magnetic steel and the lower end face of the motor stator, then flows into a gap between the inner wall of the lower magnetic steel and the outer wall of the lower bearing, then flows into a gap between the back end face of the impeller and the lower end face of the lower bearing, and finally flows into a gap between the inner wall of the lower bearing and the outer wall of the lower shaft sleeve, so that the self-lubrication of the lower bearing is completed;

the medium conveyed by the centrifugal pump continuously flows into a gap between the upper end face of the motor stator and the lower end face of the upper magnetic steel, then flows into a gap between the inner wall of the pump body and the outer wall of the upper rotor, then flows into a gap between the upper end face of the upper rotor and the first end face of the pump cover, then flows into a gap between the inner wall of the pump cover and the upper shaft sleeve and a gap between the inner wall of the upper bearing and the outer wall of the upper shaft sleeve, namely, self-lubrication of the upper bearing is realized, then flows into a gap between the upper shaft sleeve, the outer wall at the tail end of the main shaft and the inner wall of the end cover, and finally flows into the inlet of the pump body and flows out after flowing into the gap between the end face at the tail end of the main shaft and the inner bottom wall of the end cover and flowing into the balance through hole.

8. A self-lubricating method of a rare earth permanent magnet motor driven centrifugal pump, which is characterized in that the rare earth permanent magnet motor driven centrifugal pump based on claim 5 comprises the following steps:

the medium delivered by the centrifugal pump flows into the liquid guiding hole from the outlet of the pump body, then flows into the liquid guiding pipeline, then flows into the through hole on the end cover, then flows into the gap between the end face of the tail end of the main shaft and the inner bottom wall of the end cover, then flows into the upper shaft sleeve, the gap between the outer wall of the tail end of the main shaft and the inner wall of the end cover, and finally flows into the gap between the inner wall of the upper bearing and the outer wall of the upper shaft sleeve, so that the self-lubrication of the upper bearing is completed;

the medium conveyed by the centrifugal pump continuously flows into the gap between the inner wall of the pump cover and the upper shaft sleeve and the gap between the outer walls of the upper rotor and then flows into the gap between the first end face of the pump cover and the upper end face of the upper rotor, then flows into the gap between the inner wall of the pump body and the outer wall of the upper rotor and then flows into the gap between the upper end face of the motor stator and the lower end face of the upper magnetic steel, then flows into the gap between the inner wall of the lower bearing and the outer wall of the lower shaft sleeve, namely, self-lubrication of the lower bearing is realized, then flows into the gap between the lower end face of the lower bearing and the back end face of the impeller, and finally flows into the inlet of the pump body and flows out after flowing into the through hole arranged on the hub between the adjacent blades of the impeller along the axial direction of the hub.

9. A self-lubricating method for a rare earth permanent magnet motor driven centrifugal pump, which is based on the rare earth permanent magnet motor driven centrifugal pump of claim 6, comprising:

the medium delivered by the centrifugal pump flows into the liquid guiding hole from the outlet of the pump body, then flows into the liquid guiding pipeline, then flows into the through hole on the end cover, then flows into the gap between the end face of the tail end of the main shaft and the inner bottom wall of the end cover, then flows into the gap between the inner wall of the upper bearing and the outer wall of the upper shaft sleeve, namely completes the self-lubrication of the upper bearing, then flows into the gap between the inner wall of the pump cover and the outer walls of the upper shaft sleeve and the upper rotor, then flows into the radial hole on the upper rotor and the transverse hole on the main shaft, and finally flows into the inlet of the pump body and flows out after flowing into the balance through hole;

meanwhile, the medium delivered by the centrifugal pump flows into the gap between the inner wall of the pump body and the outer wall of the impeller from the outlet of the pump body and then flows into the gap between the upper end face of the lower magnetic steel and the lower end face of the motor stator, then flows into a gap between the inner wall of the lower magnetic steel and the outer wall of the lower bearing, then flows into a gap between the back end surface of the impeller and the lower end surface of the lower bearing, and then flows into a gap between the inner wall of the lower bearing and the outer wall of the lower shaft sleeve, the self-lubricating of the lower bearing is completed, then the fluid flows into the gap between the upper end face of the motor stator and the lower end face of the upper magnetic steel, then flows into the gap between the inner wall of the pump body and the outer wall of the upper rotor, then flows into the gap between the upper end face of the upper rotor and the first end face of the pump cover, then flows into the radial hole on the upper rotor and the transverse hole on the main shaft, and finally flows into the inlet of the pump body and flows out after flowing into the balance through hole.