Shield motor pump

Abstract

The invention provides a shielding motor pump which comprises a pump shell and a driving part, the driving part comprises a rotor and a stator which are located in a motor shell, the rotor is installed on a rotor shaft, and one end of the rotor shaft is inserted into the pump shell to be connected with an impeller; the rotor shaft is formed by combining a hollow pipe and blocking pieces pressed into the two ends of the hollow pipe, through holes are formed in the blocking pieces, and the through holes and an inner cavity of the hollow pipe jointly form a fluid channel; a cavity for installing the stator in the motor shell is a stator cavity, and the stator cavity is filled with a composite heat conduction material. A pilot-operated type mechanical protection mechanism is constructed, when the radial displacement of the rotor is increased due to abrasion of the bearing, the limiting assembly can make contact with the stator and rotor shielding sleeves in advance, and therefore early warning is provided for the system, further displacement is physically limited, and disastrous faults such as shielding sleeve tearing and medium leakage are fundamentally prevented.

Description

Technical Field

[0001] This invention relates to the field of fluid machinery, and in particular to a canned motor pump. Background Technology

[0002] Canned motor pumps, as a key piece of equipment that completely encloses the motor and pump body to achieve leak-free transport, have irreplaceable advantages in conveying corrosive, flammable, explosive, or high-purity media in fields such as chemical, pharmaceutical, nuclear, and energy industries. Their core feature lies in the complete isolation of the stator and rotor parts of the motor from the transported medium through stator and rotor shielding sleeves. However, with the increasing demands for equipment reliability, energy efficiency, and total life-cycle cost in industrial applications, several inherent defects exposed in long-term practice of traditional canned motor pumps have become technical bottlenecks restricting their development towards higher performance.

[0003] Firstly, traditional designs face significant challenges in the manufacturing process and cost control of key rotating components. The rotor spindle of a canned motor pump not only bears the heavy responsibility of transmitting torque and supporting rotating components, but also typically requires a central through-hole machined along its entire length as a crucial flow channel for cooling medium circulation and heat dissipation from the motor. Current technology generally uses solid alloy steel bars as the starting point, forming this through-hole through-hole by deep-hole drilling. Because the spindle is a slender shaft with a very high length-to-diameter ratio, performing deep-hole drilling in a single operation is extremely difficult: the drill bit is prone to skew, causing the hole axis to become misaligned and affecting dynamic balance; chip removal during machining is difficult, easily leading to drill bit wear or even breakage; and stringent requirements are placed on machine tool rigidity, the guiding system, and cooling and lubrication. This results in lengthy machining processes, difficulty in guaranteeing yield, and directly leads to high manufacturing costs for the spindle component, accounting for a significant portion of the overall machine cost. Furthermore, the use of solid bars to ensure strength also results in unnecessary material waste. Therefore, the industry urgently needs a new structural solution that can fundamentally simplify the rotor spindle manufacturing process and avoid the difficulties of deep-hole machining.

[0004] Secondly, traditional stator cooling solutions involve introducing some of the medium from inside the pump into the rotor, indirectly cooling the stator while simultaneously cooling the rotor. This results in severely insufficient stator cooling.

[0005] Finally, canned motor pumps typically use media-lubricated sliding bearings. During long-term operation, especially when conveying media containing small particles or with poor lubricity, the bearings inevitably experience uniform or non-uniform wear, leading to a gradual increase in the radial clearance of the rotor system. When wear accumulates to a certain extent, under the action of centrifugal or fluid forces, the outer rotor shielding sleeve may come into contact and rub against the inner stator shielding sleeve. Since the shielding sleeves are thin-walled metal components, this contact easily leads to scratches or even tears. Once the shielding sleeve ruptures, the conveyed process media (which may be corrosive, conductive, or flammable) will rush into the motor stator cavity, instantly causing winding short circuits, insulation failure, and motor burnout, while also causing media leakage, posing safety and environmental risks. Repairing such faults is extremely difficult, often requiring the replacement of the entire motor unit, which is very costly. Traditional solutions mainly rely on improving the wear resistance of the bearing material and optimizing the lubrication channel design to extend bearing life, but these are measures that delay risk. The equipment lacks an ultimate protection device that can actively and mechanically prevent catastrophic rotor displacement in the early stages of bearing function decline or at the moment of failure.

[0006] Furthermore, the design of canned motor pumps faces a structural contradiction: from the perspective of electromagnetic shielding efficiency and reducing eddy current losses, the shield wall thickness is desired to be as thin as possible; however, the heat load generated by the heat generated in the stator cavity will cause thermal stress and pressure on the thin-walled shield, easily leading to deformation, bulging, or even instability. Once the shield deforms, it will directly threaten the already small operating clearance between it and the rotor, increasing the risk of collision. Therefore, existing technologies have to appropriately increase the shield wall thickness, sacrificing some shielding performance in exchange for sufficient mechanical strength and shape stability. This leads to an inherent performance bottleneck: if the shield is too thick, it will reduce shielding effectiveness and increase eddy current heating, while if it is too thin, it will pose safety hazards.

[0007] Therefore, developing a new type of shielded motor pump structure that can systematically solve the problem of making the shield thinner and lighter, while also having low cost, efficient heat dissipation and high safety redundancy, has become a clear and urgent development direction in this technical field. Summary of the Invention

[0008] To address the shortcomings of existing technologies, this invention provides a canned motor pump that solves the problems of manufacturing cost, heat dissipation performance, and bearing failure protection in traditional canned motor pumps.

[0009] The present invention achieves the above-mentioned technical objectives through the following technical means.

[0010] A shielded motor pump includes a pump casing and a drive unit. The drive unit includes a rotor and a stator located in the motor casing. The rotor is mounted on a rotor shaft, one end of which is inserted into the pump casing and connected to an impeller. The rotor shaft is composed of a hollow tube and plugs pressed into both ends of the hollow tube. Each plug has a through hole, which, together with the inner cavity of the hollow tube, forms a fluid channel. The cavity in the motor casing where the stator is installed is called the stator cavity, which is filled with a composite thermally conductive material.

[0011] Furthermore, the plugging component includes a plugging ring and a rotating shaft. The plugging ring is installed in the middle of the rotating shaft. A right protruding key is provided on the right end face of the plugging ring. One end of the rotating shaft located on one side of the plugging ring is inserted into a hollow tube. The right protruding key on the plugging ring is splined with one end of the hollow tube. The other end of the rotating shaft located on the other side of the plugging ring is supported in a bearing seat.

[0012] Furthermore, a left convex key is provided on the left end face of the blocking ring, and a positioning ring is provided on the rotating shaft on the other side of the blocking ring. The inner ring of the positioning ring is connected to the left convex key. A gap is provided between the positioning ring and the bearing seat.

[0013] Furthermore, the other end of the rotating shaft is supported in a bearing housing by a bearing; a limiting protection assembly is provided on one side of the rotating shaft support, the limiting protection assembly including a limiting ring inner sleeve and a limiting ring; the limiting ring inner sleeve is installed on the rotating shaft, the limiting ring is installed in the bearing housing, and a radial clearance D1 is provided between the limiting ring inner sleeve and the limiting ring; a shield is provided inside the motor housing to isolate the rotor and the stator, and the radial clearance between the shield and the rotor is D2, D1 <D2。

[0014] Furthermore, the inner ring of the limiting ring is provided with staggered concave lobes and convex lobes, and a radial gap D1 is provided between the convex lobes and the outer ring of the inner sleeve of the limiting ring; the concave lobes are connected to the cooling medium channel.

[0015] Furthermore, the limiting ring and the inner sleeve of the limiting ring are made of a high-friction material; the high-friction material is a non-asbestos organic material or a semi-metallic friction material.

[0016] Furthermore, the composite thermally conductive material comprises multiple dry spherical inorganic material particles in contact with each other and silicone resin filling and curing the gaps between the particles; the spherical inorganic material particles are ceramic balls or glass beads.

[0017] Furthermore, a liquid cooling device is installed on the outside of the stator cavity for heat exchange with the composite thermally conductive material of the stator cavity.

[0018] The beneficial effects of this invention are as follows:

[0019] 1. The shielded motor pump of this invention, by employing a rotor spindle assembled from a hollow tube and independent plugs at both ends, completely eliminates the complex process of deep hole drilling from a traditional solid bar stock. This achieves the effects of significantly simplifying the machining process of rotating parts, significantly reducing material loss and manufacturing costs, while ensuring the integrity of the internal fluid channels.

[0020] 2. The shielded motor pump of the present invention provides a reliable torque transmission path and precise circumferential positioning for the split-type spindle by setting a blocking ring and a key on the blocking component and connecting it to the end of the hollow tube using a spline fit. This achieves the effect of ensuring the structural rigidity and connection reliability of the rotor spindle under high-speed operation, effectively guaranteeing the power transmission efficiency.

[0021] 3. The shielded motor pump of the present invention provides a precise axial positioning reference for the rotor system in the bearing housing by setting a left protruding key connected to the positioning ring key on the other side of the blocking ring and maintaining a gap between the positioning ring and the bearing housing. At the same time, it avoids the assembly stress caused by rigid constraints, realizes the precise axial positioning of the rotor shaft, facilitates assembly and debugging, can tolerate a certain thermal expansion, and improves the operational stability.

[0022] 4. The canned motor pump of the present invention, by setting a protective component consisting of a limiting ring inner sleeve and a limiting ring on the shaft support side, and controlling the radial gap D1 between the limiting ring inner sleeve and the limiting ring to be smaller than the gap D2 between the shield and the rotor, constructs a pilot mechanical protection mechanism. When the bearing wear causes the rotor radial displacement to increase, the limiting component can contact the stator and rotor shield sleeves first, thereby providing an early warning for the system and physically limiting further displacement, fundamentally preventing catastrophic failures such as shield sleeve tearing and medium leakage.

[0023] 5. The shielded motor pump of the present invention designs the inner ring of the limiting ring with staggered concave and convex lobes, and forms a protective gap D1 between the inner surface of the convex lobes and the outer ring of the inner sleeve of the limiting ring. At the same time, the concave lobes are connected to the cooling medium channel. In this way, during normal operation, the cooling medium can pass smoothly through the concave lobes channel without affecting the system's heat dissipation and lubrication. Only when a fault is triggered will the convex lobes contact the inner sleeve and generate resistance, thus achieving the effect of functional reuse and space optimization.

[0024] 6. The shielded motor pump of the present invention enhances the friction characteristics of the protection components when they are triggered into contact by using non-asbestos organic materials or semi-metallic high-friction materials to manufacture the limiting ring and the inner sleeve of the limiting ring. This results in a sufficiently large rotational resistance when the limiting components are in contact, thereby causing a significant change in the motor current or increased vibration, and providing a clear and reliable fault shutdown signal for the control system.

[0025] 7. The shielded motor pump of the present invention constructs a highly efficient thermally conductive stator cavity without continuous air gaps by filling the stator cavity with a composite material consisting of dry, spherical inorganic material particles (such as ceramic balls or glass beads) in contact with each other and high thermal conductivity silicone resin filling the gaps between them and curing it. This greatly improves the efficiency of heat transfer from the stator core and coils to the housing, effectively reducing the internal operating temperature of the motor, delaying insulation aging, and improving the power density and long-term operational reliability of the motor. The application of spherical particles also avoids potential damage to the coil insulation from sharp fillers. In addition, by using the composite thermally conductive filler cured in the stator cavity to form an integral rigid support structure that wraps around and tightly adheres to the inner surface of the shield, the shield is provided with effective internal support and constraint. This allows for a significant reduction in the wall thickness of the shield, greatly improving the electromagnetic shielding effect and reducing eddy current losses while ensuring that it does not undergo thermal deformation or mechanical instability. Thus, the motor efficiency is optimized in terms of both structural lightweighting and electromagnetic performance.

[0026] 8. The shielded motor pump of the present invention provides an enhanced external heat dissipation path for efficiently dissipating heat by installing a liquid cooling device on the outer shell of the stator cavity. It achieves synergistic work with the internal composite thermal conductive material to form a complete thermal management system with efficient internal conduction and strong external dissipation, enabling the motor to adapt to higher power loads and more demanding heat dissipation environments. Attached Figure Description

[0027] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. The drawings described below are some embodiments of the present invention. For those skilled in the art, it is obvious that other drawings can be obtained from these drawings without creative effort.

[0028] Figure 1 This is a front view of the shielded motor pump described in this invention.

[0029] Figure 2 This is a sectional view of the rotor shaft described in this invention.

[0030] Figure 3 This is an exploded view of the rotor shaft described in this invention.

[0031] Figure 4 This is an enlarged schematic diagram of the radial clearance of the present invention.

[0032] Figure 5 This is a schematic diagram of the installation of the limit protection component described in this invention.

[0033] Figure 6 The main view of the assembly of the limit protection component described in this invention.

[0034] Figure 7 This is a schematic diagram of the cooling channel described in this invention.

[0035] In the picture:

[0036] 1-Pump casing; 2-Impeller; 3-Front bearing housing; 4-Motor housing; 5-Shielding cover; 6-Left stator filler; 7-Right stator filler; 8-Coil; 9-Exhaust valve; 10-Left nut; 11-Left plug; 11a-Right key; 11b-Left key; 11c-Plug thread; 11d-Plug through hole; 11e-Plug ring; 11f-Plug threaded hole; 12-Limit ring inner sleeve; 13-Limit ring; 13a-Concave flap; 13b-Protruding flap; 14-Positioning ring; 15-Bearing support; 16-Hollow tube; 16a-Hollow tube key; 16b-Hollow tube groove; 16f-Hollow tube stepped through hole; 17-Rotor outer sleeve; 18-Rotor; 19-Stator; 20-Right nut; 21-Rear bearing housing; 22-Right plug; 23-Bearing. Detailed Implementation

[0037] Embodiments of the present invention are described in detail below, examples of which are illustrated in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and intended to explain the present invention, and should not be construed as limiting the present invention.

[0038] In the description of this invention, it should be understood that the terms "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "axial," "radial," "vertical," "horizontal," "inner," and "outer," etc., indicating orientation or positional relationships based on the orientation or positional relationships shown in the accompanying drawings, are only for the convenience of describing the invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of the invention. Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Thus, a feature defined with "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this invention, "a plurality of" means two or more, unless otherwise explicitly specified.

[0039] In this invention, unless otherwise explicitly specified and limited, the terms "installation," "connection," "linking," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0040] like Figure 1 As shown, the canned motor pump of the present invention includes a pump casing 1 and a drive unit. The drive unit and the pumping unit are integrated into a closed housing. The housing includes the pump casing 1 and the motor housing 4. The pump casing 1 forms the main flow channel of the pumping unit, with its front end connected to the suction port and its upper end connected to the discharge port. An impeller 2 is installed inside the pump casing 1. The drive unit is encapsulated inside the motor housing 4. The motor housing 4 is typically composed of a front cover, an outer cylinder, and a rear cover. The front bearing seat 3 and the rear bearing seat 21 are respectively fixed to the inner sides of both ends of the motor housing 4 to support the rotor shaft. An exhaust valve 9 is installed at the rear to remove gas accumulated in the pump. The drive unit includes a rotor 18 and a stator 19. The rotor 18 is mounted on a rotor shaft. One end of the rotor shaft is inserted into the pump casing 1 and connected to the impeller 2. The rotor 18 has a rotor sleeve 17 that wraps around it, and the rotor sleeve 17 can be considered as part of the rotor 18.

[0041] like Figure 2 and Figure 3 As shown, the rotor shaft of the present invention is composed of a hollow tube 16 and a left plug 11 and a right plug 22 pressed into both ends of the hollow tube. Each plug has a through hole, which together with the inner cavity of the hollow tube 16 forms a fluid channel. The hollow tube 16 is made of seamless tube as blank material. Only the inner hole and outer circle need to be precision turned or ground to obtain a base material with the required precision. Compared with the long deep hole drilling from solid bar material, the cost and time are greatly reduced.

[0042] The hollow tube 16 has a left plug 11 and a right plug 22 connected to its two ends, respectively. The left plug 11 and the right plug 22 can be considered as shaft head components. The left plug 11 and the right plug 22 have the same structure. Taking the left plug 11 as an example, its structure is described in detail. In order to ensure an effective connection between the shaft head component and the hollow tube 16 and to meet the requirements of coaxiality and torsional rigidity under high-speed rotation, the hollow tube 16 of the present invention has several axially extending, spaced hollow tube grooves 16b machined on the outer circumference of both ends, forming an intersecting groove. The hollow tube protrusions 16a and hollow tube grooves 16b are arranged to form a spline structure. The left plug 11 includes a plug ring 11e and a rotating shaft. The plug ring 11e is installed in the middle of the rotating shaft. The right end face of the plug ring 11e is provided with a right protrusion 11a. One end of the rotating shaft located on one side of the plug ring 11e is inserted into the hollow tube 16. The right protrusion 11a is aligned and slid into the hollow tube groove 16b, forming a spline-type circumferential fit, which solves the problems of torque transmission and angular positioning. A hollow tube stepped through hole 16f is machined on the wall thickness of the spline mating area. At the same time, a plug thread hole 11f is machined at the corresponding position on the rotating shaft. After the spline is in place, the fixing screw is passed through the hollow tube stepped through hole 16f and screwed into the plug thread hole 11f to tighten it, so that the hollow tube 16 and the left plug 11 are tightly connected into a rigid integral shaft. The other end of the shaft located on the other side of the plugging ring 11e is supported in the front bearing housing 3. The other end of the shaft of the left plugging member 11 is connected to the impeller 2 via a drive, and the impeller is axially installed by the threaded engagement of the left nut 10 with the other end of the shaft. The left end face of the plugging ring 11e is provided with a left protruding key 11b, and a positioning ring 14 is provided on the shaft located on the other side of the plugging ring 11e. The inner ring of the positioning ring 14 is keyed to the left protruding key 11b; there is an axial clearance between the positioning ring 14 and the front bearing housing 3. Similarly, the right end of the right plugging member 22 is supported in the rear bearing housing 21. The right end of the right plugging member 22 is also threaded. By installing the right nut 20, the bearing in the rear bearing housing 21 is pressed, thereby achieving the axial positioning of the right plugging member 22. The left plug 11 and the right plug 22 are provided with axial plug through holes 11d at their centers. The plug through holes 11d are connected to the inner cavity of the hollow tube 16, and together they form a circulation channel for the cooling medium inside the motor.

[0043] The assembly of the rotor core and the hollow tube 16 primarily employs an interference fit. Typically, the rotor core is heated and then heat-fitted onto the outer circumference of the hollow tube 16, with the interference amount controlled between 0.03-0.06 mm. This ensures a firm bond under centrifugal force. The overall assembly of the rotor 18 involves inserting the permanent magnets and insulating sheets into the core, then fitting the rotor outer sleeve 17 and welding the end plates for sealing. These processes are similar to those of conventional permanent magnet motors.

[0044] like Figure 5 and Figure 6As shown, a limit protection component is provided on the side of the rotating shaft support. Taking the left plugging member 11 as an example, the limit protection component includes a limit ring inner sleeve 12 and a limit ring 13; the limit ring inner sleeve 12 is installed on the rotating shaft, the limit ring 13 is installed in the front bearing seat 3, and there is a radial gap D1 between the limit ring inner sleeve 12 and the limit ring 13; a shielding cover 5 for isolating the rotor 18 and the stator 19 is provided in the motor housing 4, and the radial gap between the shielding cover 5 and the rotor 18 is D2, D1 < D2, as Figure 4 shown.

[0045] The inner ring of the limit ring 13 is provided with alternately distributed concave lobes 13a and convex lobes 13b, and there is a radial gap D1 between the inner diameter of the convex lobe 13b and the outer ring of the limit ring inner sleeve 12; the concave lobe 13a is communicated with the cooling medium channel, which can generally be the lubrication flow channel of the bearing seat as the cooling medium channel. The limit ring 13 and the limit ring inner sleeve 12 are made of high-friction materials; the high-friction materials are non-asbestos organic substances or semi-metallic friction materials. When the bearing 23 supporting the rotor shaft is worn due to long-term operation, the radial movement of the rotor shaft gradually increases. Once the wear accumulation makes the radial displacement of the rotor shaft reach the dimension D1, the rotating limit ring inner sleeve 12 will first contact the inner surface of the convex lobe 13b of the limit ring 13. Since the limit ring 13 and the limit ring inner sleeve 12 are made of high-friction materials, such instantaneous contact will generate a huge rotational resistance. At this time, the motor current rises sharply and is accompanied by severe vibration, and the control system can immediately give an alarm and stop the machine accordingly. Since D1 is less than D2, before the rotor outer sleeve 17 may rub against the shielding cover 5, an alarm is triggered, that is, it fuses actively before a potential major fault occurs, thus completely avoiding the accident of the shielding sleeve breaking and the medium invading the motor cavity. During normal operation, the coolant can freely pass through the flow channel in the area of the concave lobe 13a, and this protection component has no influence on the performance of the pump.

[0046] The cavity in the motor housing 4 for installing the stator 19 is the stator cavity, and a composite heat-conducting material is filled in the stator cavity. The silicon steel sheets and coils 8 of the stator 19 are installed in the stator cavity. On the left and right sides of the stator cavity, there are left stator fillers 6 and right stator fillers 7. The composite heat-conducting material includes a plurality of dry spherical inorganic material particles in contact with each other and a silicone resin filled and cured in the particle gaps; the spherical inorganic material particles are ceramic balls or glass beads.

[0047] As shown in the figure, the stator cavity formed by the shield 5 and the inner wall of the motor housing 4 is filled with composite thermally conductive material, forming a robust inner-liner-like support structure. This changes the stress state of the shield 5. In traditional designs, thin-walled shields need to bear the internal heat load and possible fluid pressure alone, making them prone to instability. However, the shield 5 of this invention receives full support from the rigid internal filler, greatly enhancing its resistance to deformation. This allows the wall thickness of the shield 5 to be within a relatively thin range of 0.2 to 0.5 mm. This thickness of shield not only effectively meets the sealing requirements of the isolation medium, but more importantly, it results in significantly lower eddy current losses compared to traditional thick-walled designs, improving motor efficiency. Simultaneously, due to the constraint of the internal filler, this thin-walled shield maintains shape stability under long-term high-temperature and high-pressure operating conditions, fundamentally eliminating the risk of interference with the rotor due to its own deformation, achieving a balance between safety and high performance.

[0048] The filling process includes the following steps:

[0049] First, a large quantity of dry, spherical inorganic material particles, such as uniformly sized alumina ceramic spheres or high borosilicate glass beads, are poured into the stator cavity through pre-drilled process holes in the outer casing, typically near the junction box. During the pouring process, the casing is slightly vibrated, allowing the excellent flowability and packing properties of the spherical particles to automatically fill every complex corner of the cavity, forming a lattice of tightly packed particles. This densely packed layer of spherical particles constitutes a rigid, highly thermally conductive skeletal network.

[0050] Next, liquid silicone resin with higher thermal conductivity is injected into the stator cavity already filled with particles. Due to the micron-sized gaps between the particles, the silicone resin rapidly penetrates and fills all the voids through capillary action. To reduce the resin viscosity and improve its flowability for complete wetting, it can be diluted with a suitable solvent before injection.

[0051] Finally, heating is used to induce a cross-linking reaction in the silicone resin, which is then cured and molded. The cured silicone resin firmly bonds the dispersed spherical particles into a single structure. Because the spherical particles hardly shift during the curing process, the entire filler has good volume stability and does not generate significant shrinkage stress like pure resin after curing. This allows for a near-perfect tight fit with the inner wall of the shield 5, the stator silicon steel sheet, and the surface of the coil 8, eliminating the interfacial air gaps that are difficult to avoid in traditional filling processes.

[0052] This invention fills the stator cavity with a composite thermally conductive material, forming an extremely low thermal resistance path from the internal heat source coil and iron core to the motor housing 4. Heat can be conducted through the particle contact points and then diffused away through the resin matrix. Furthermore, the smooth, hard spherical particles will not damage the coil insulation, and the solidified whole also provides the added benefit of supporting the shield and suppressing its vibration. A liquid cooling device can also be installed on the outside of the stator cavity to exchange heat with the internal composite thermally conductive material, forming an active heat dissipation system.

[0053] The left plug 11 also has a first through hole for radial cooling on its rotating shaft. The first through hole communicates with the central plug through hole 11d. The first through hole is located near the inner sleeve of the limiting ring and is used to introduce the cooling medium into the limiting protection assembly. Figure 1 and Figure 7 As shown, the pump's fluid path is divided into a main flow and an internal circulation. Main flow channel: The medium enters from the inlet of pump casing 1, is pressurized by impeller 2, and is discharged from the outlet, i.e., a→c→b in the figure; Internal flow channel: A portion of the high-pressure medium enters the motor cavity through the rear flow channel, flows sequentially through the rear bearing housing 21 area, the rotor main shaft internal channel (right plug through hole → hollow tube cavity → left plug through hole), and the front bearing housing 3 area, lubricating the bearing and carrying away the motor heat, and finally converges back to the high-pressure area, forming a closed loop, i.e., c→d→e→f→g→h→j→k→c in the figure; During the internal circulation process, the high-pressure medium passing through the right plug through hole 11d can also allow some of the medium to enter the bearing interior for cooling through the first through hole and concave petal 13a.

[0054] It should be understood that although this specification is described according to various embodiments, not every embodiment contains only one independent technical solution. This way of describing the specification is only for clarity. Those skilled in the art should regard the specification as a whole. The technical solutions in each embodiment can also be appropriately combined to form other implementation methods that can be understood by those skilled in the art.

[0055] The detailed descriptions listed above are merely specific illustrations of feasible embodiments of the present invention and are not intended to limit the scope of protection of the present invention. All equivalent embodiments or modifications made without departing from the spirit of the present invention should be included within the scope of protection of the present invention.

Claims

1. A canned motor pump, comprising a pump casing (1) and a drive unit, the drive unit comprising a rotor (18) and a stator (19) located in a motor housing (4), the rotor (18) being mounted on a rotor shaft, one end of the rotor shaft being inserted into the pump casing (1) and connected to an impeller (2); characterized in that, The rotor shaft is composed of a hollow tube (16) and plugs pressed into both ends of the hollow tube. Each plug has a through hole, and the through hole and the inner cavity of the hollow tube (16) together form a fluid channel. The cavity in the motor housing (4) where the stator (19) is installed is the stator cavity, which is filled with composite heat-conducting material.

2. The canned motor pump according to claim 1, characterized in that, The plugging component includes a plugging ring (11e) and a rotating shaft. The plugging ring (11e) is installed in the middle of the rotating shaft. The right end face of the plugging ring (11e) is provided with a right protruding key (11a). One end of the rotating shaft located on one side of the plugging ring (11e) is inserted into a hollow tube (16). The right protruding key (11a) on the plugging ring (11e) is splined with one end of the hollow tube (16). The other end of the rotating shaft located on the other side of the plugging ring (11e) is supported in a bearing seat.

3. The canned motor pump according to claim 2, characterized in that, The left end face of the plugging ring (11e) is provided with a left convex key (11b), and a positioning ring (14) is provided on the rotating shaft on the other side of the plugging ring (11e). The inner ring of the positioning ring (14) is key-connected to the left convex key (11b); there is a gap between the positioning ring (14) and the bearing seat.

4. The canned motor pump according to claim 2, characterized in that, The other end of the rotating shaft is supported in a bearing housing by a bearing (23); a limiting protection assembly is provided on one side of the rotating shaft support, the limiting protection assembly including a limiting ring inner sleeve (12) and a limiting ring (13); the limiting ring inner sleeve (12) is installed on the rotating shaft, the limiting ring (13) is installed in the bearing housing, and a radial gap D1 is provided between the limiting ring inner sleeve (12) and the limiting ring (13); a shield (5) is provided inside the motor housing (4) to isolate the rotor (18) and the stator (19), and the radial gap between the shield (5) and the rotor (18) is D2, D1 <D2。 5. The canned motor pump according to claim 4, characterized in that, The inner ring of the limiting ring (13) is provided with staggered concave lobes (13a) and convex lobes (13b), and a radial gap D1 is provided between the convex lobes (13b) and the outer ring of the inner sleeve (12) of the limiting ring; the concave lobes (13a) are connected to the cooling medium channel.

6. The canned motor pump according to claim 4, characterized in that, The limiting ring (13) and the inner sleeve of the limiting ring (12) are made of high friction material; the high friction material is a non-asbestos organic material or a semi-metallic friction material.

7. The canned motor pump according to claim 1, characterized in that, The composite thermally conductive material comprises multiple dry spherical inorganic material particles in contact with each other and silicone resin filling and curing the gaps between the particles; the spherical inorganic material particles are ceramic spheres or glass beads.

8. The canned motor pump according to claim 1, characterized in that, A liquid cooling device is installed on the outside of the stator cavity for heat exchange with the composite thermally conductive material of the stator cavity.

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