Outer rotor motor-driven canned electric pump for delivering coolant

Abstract

The shielded electric pump driven by an outer rotor motor for conveying cooling liquid comprises a pump cover, a pump body and a volute chamber enclosed by both, a core shaft in the center of the pump cover and the pump body for supporting an impeller, an inlet pipe along the axis of the impeller leading to the suction side of the volute chamber and opening downward, the inlet pipe passing through the center of the stator of the outer rotor motor, a cylindrical stator cavity adjoining the inlet pipe and opening downward, the stator of the outer rotor motor being accommodated in the stator cavity, the inner and outer periphery of the stator being in heat-conducting contact with the inner and outer cavity walls of the stator cavity respectively, a cylindrical rotor cavity surrounding the stator cavity and opening upward through the volute chamber for accommodating the rotor of the outer rotor motor. In addition to the fact that the outer rotor is completely surrounded by the pump liquid, the inner and outer periphery of the inner stator core can also achieve heat-conducting conduction with the flowing pump liquid, so that the cooling liquid is driven for use while dissipating the heat generated by the motor, thereby improving the pump efficiency and eliminating the need for additional cooling devices, which helps to reduce the size of the pump.

Description

Technical Field

[0001] This invention relates to a shielded electric pump driven by an external rotor motor for conveying coolant, and its IPC classification may be F04D13 / 06, F04D29 / 58 or F04D29 / 40. Background Technology

[0002] Existing technology for shielded electric pumps driven by external rotor motors can be found in Chinese patent documents CN2844514Y, CN104179693B and CN109983232A and Taiwan patent document TW200928117A. Their cooling structure still needs further improvement to reduce the temperature rise of the motor.

[0003] For terms and general knowledge in this manual, please refer to the national standard GB / T 33925.1 "General terms, definitions, quantities, characters and units for liquid pumps and their devices - Part 1: Liquid pumps" and GB / T 7021 "Centrifugal pumps - Terminology", the mechanical industry standard JB / T 5415 "Miniature centrifugal electric pumps", the 1992 edition of "IEC Electrical and Electronic Standards Terminology Dictionary" published by China Standards Press, the 1983 or 1997 editions of "Mechanical Engineering Handbook" and "Electrical Engineering Handbook" published by Machinery Industry Press, the 2014 edition of "Pump Theory and Technology" published by Machinery Industry Press, and the 2011 edition of "Modern Pump Theory and Design" published by China Aerospace Press. Summary of the Invention

[0004] The purpose of this invention is to provide a canned motor pump driven by an external rotor motor for conveying coolant, which improves heat transfer efficiency and reduces pump size compared to existing technologies. This canned motor pump includes:

[0005] —Pump cover, pump body, and the volute enclosed by the two;

[0006] —A spindle that supports the impeller along the axis of the volute and the pump cover and pump body;

[0007] —An inlet pipe extending along the axis of the volute to the suction side of the volute and opening downwards, the inlet pipe passing through the center of the stator of the external rotor motor;

[0008] —A cylindrical stator cavity surrounding the inlet pipe and with its opening facing downwards; the stator of an external rotor motor housed within the stator cavity; the inner and outer circumferences of the stator of the external rotor motor are in thermal contact with the inner and outer walls of the stator cavity, respectively.

[0009] —A cylindrical rotor cavity surrounding the stator cavity and opening upwards through the volute, used to house the rotor of the external rotor motor.

[0010] Except for the rotor, which is completely surrounded by the pumping fluid, the inner stator core of this shielded electric pump can conduct heat to the flowing pumping fluid from both the inner and outer circumferences (heat conduction without being isolated by air, which has extremely low thermal conductivity). This allows the coolant to be driven for use while dissipating the heat generated by the motor, thus improving pump efficiency and eliminating the need for an additional cooling device, which helps to reduce pump size.

[0011] Furthermore, one end of the pump body inlet pipe is provided with a suction port for inputting coolant, and the other end, which connects to the volute, is provided with a support base for supporting the mandrel. The connection between the support base and the inlet pipe wall is provided with several inlet pipe through holes connecting to the volute. This structure can guide coolant to the volute to be driven by the impeller, while fixing both ends of the mandrel, increasing the stability of pump operation.

[0012] Furthermore, the inlet pipe, stator cavity, and rotor cavity are integrally injection molded into a concave-convex shape when viewed along the axis. The functional structures are interlocked and integrally formed in the axial direction, resulting in a compact and simple structure that helps reduce pump size and facilitates efficient manufacturing.

[0013] Preferably, the rotor has a cylindrical support with a bottom wall at one end and an open end. A permanent magnet is fixed to the inner wall of the cylinder. A through hole is provided at the center of the bottom wall, and the outer edge of the through hole protrudes axially outward to form a protrusion defining the spindle. An impeller for driving the coolant is fixed to the upper surface of the bottom wall around the protrusion. Several side through holes are provided at the junction of the protrusion and the bottom wall to guide the coolant flowing in through the through hole to the impeller flow channel. This rotor structure can guide the coolant input from the inlet pipe to the impeller that rotates with it, and the impeller drives the coolant to be discharged from the pump.

[0014] Furthermore, the top of the cylindrical wall of the support is provided with several return holes. By utilizing the centrifugal force of the rotating cylinder, the internal coolant is guided to the return holes at the top of the inner wall of the cylinder and discharged back into the volute, thereby realizing the flow of coolant in the rotor cavity.

[0015] Furthermore, the centerline of the return hole is located at the junction of the cylindrical wall and the bottom wall. This location allows most of the coolant to flow back to the volute and avoids the accumulation of residue at the junction.

[0016] Furthermore, it also includes a control board disposed at the opening end of the stator cavity and a connector integrally injection molded with the pump body for detachable electrical connection to an external power source, wherein the control board is electrically connected to the connector. This structure enables detachable connection between the motor and an external power source.

[0017] Furthermore, the heating power element on the control board is in direct or through a heat-conducting component in contact with the inlet pipe, so that the heat emitted by the heating power element can be dissipated through the flowing coolant, avoiding excessive temperature and affecting the stability of the control board performance. Attached Figure Description

[0018] Figure 1 This is a front view of Embodiment 1 of the canned electric pump driven by an external rotor motor for conveying coolant according to the present invention;

[0019] Figure 2 yes Figure 1 AA section view;

[0020] Figure 3 This is a schematic diagram of the coolant flow direction in Embodiment 1 of the shielded electric pump driven by an external rotor motor for conveying coolant according to the present invention.

[0021] Figure 4 This is a cross-sectional view of the pump body along the axial direction of Embodiment 1 of the canned electric pump driven by an external rotor motor for conveying coolant according to the present invention.

[0022] Figure 5 This is an axial cross-sectional view of the rotor embodiment one of the shielded electric pump driven by an external rotor motor for conveying coolant according to the present invention.

[0023] Figure 6 This is an axial cross-sectional view of the rotor embodiment two of Embodiment 1 of the shielded electric pump driven by an external rotor motor for conveying coolant according to the present invention.

[0024] Figure 7 This is an axial cross-sectional view of the rotor embodiment three of Embodiment 1 of the shielded electric pump driven by an external rotor motor for conveying coolant according to the present invention.

[0025] Figure 8 This is an axial cross-sectional view of Embodiment 2 of the canned electric pump driven by an external rotor motor for conveying coolant according to the present invention;

[0026] Figure 9 This is an axial cross-sectional view of the rotor of Embodiment 2 of the canned electric pump driven by an external rotor motor for conveying coolant according to the present invention.

[0027] Figure label:

[0028] 10—Pump cover; 101—Discharge port; 102—Vortex chamber; 103—Spindle; 20—Rotor; 201—Support; 202—Impeller; 203—Guide hole; 204—Permanent magnet; 205—Bottom wall; 206—Through hole; 207—Bearing support seat; 208—Bearing; 209—Side through hole; 210—Spindle support seat; 30—Stator; 40—Pump body; 401—Inlet pipe; 402—Suction port; 403—Stator cavity; 404—Rotor cavity; 4041—Inlet; 405—Support seat; 4051—Inlet pipe through hole; Second bearing—406; 50—Control panel; 60—Rear cover plate. Detailed Implementation

[0029] The term "thermally conductive contact" as used in this specification specifically refers to a contact between two parts without an air gap, including a contact that is in close contact with or between two parts filled with a material with high thermal conductivity such as thermally conductive grease to form a contact with good thermal conductivity; "above" or "upper side" refers to the side of the electric pump that is closer to the volute, while "below" or "lower side" is the opposite.

[0030] To facilitate understanding of the present invention, the present invention will be described more fully below in conjunction with embodiments.

[0031] Figure 1-2 This diagram shows a front view and a cross-sectional view of an embodiment 1 of a shielded electric pump driven by an external rotor motor for conveying coolant according to the present invention. The pump includes a pump cover 10 and a pump body 40. The pump cover 10 and the pump body 40 are fixedly connected and enclosed to form a volute 102. The pump cover 10 has a discharge port 101 communicating with the volute 102. One end of a spindle 103 is fixed at the center of the pump cover 10. The pump body 40 is generally cylindrical, with fixing flanges at both ends. Figure 1 As shown, the flange is also provided with bolt posts in the circumferential direction. In this embodiment, the pump cover 10 and the pump body 40 are fixedly connected by bolts. Of course, it is also feasible to use traditional processes such as hot melt welding or sealant bonding for fixed connection. Figure 4 As shown, the inlet pipe 401, stator cavity 403, and rotor cavity 404 are integrally injection-molded pump bodies 40 with a concave-convex cross-section along the axis. The pump body 40 has an inlet pipe 401 at its center, which connects to external coolant. One end of the inlet pipe has a suction port 402, and the other end connects to the volute 102. A support seat 405 is located at the center of the end of the inlet pipe connecting to the volute 102, which supports the other end of the spindle 103. The connection between the support seat 405 and the inner wall of the inlet pipe has several inlet pipe through holes 4051, preferably three or four, connecting to the volute 102. A cylindrical stator cavity 403, coaxial with the inlet pipe 401, is located on its outer periphery. The stator cavity 403 is open at the end facing the suction port 402. A cylindrical rotor cavity 404, coaxial with the stator cavity 403, is located on its outer periphery. The rotor cavity 404 has an opening at the end facing the volute 102 and communicates with the volute 102.

[0032] The electric pump also includes a stator 30 and a rotor 20 of an external rotor motor. The stator 30 is fixedly installed in the stator cavity 403 of the pump body. Specifically, the outer periphery of the stator 30 core is in direct contact with the outer cavity wall of the stator cavity 403 (i.e., the inner cavity wall of the rotor cavity 404), or the outer periphery of the stator 30 core is filled with thermally conductive silicone grease for thermal contact. The inner periphery of the stator 30 core is in direct contact with the inner cavity wall of the stator cavity 403 (i.e., the wall of the inlet pipe 401), or the inner periphery of the stator 30 core is filled with thermally conductive silicone grease for thermal contact. In this way, the stator 30 core and the coolant flowing through the inlet pipe are not isolated by air, which has low thermal conductivity. Good heat conduction can be achieved between the coolant and the inlet pipe wall. Similarly, good heat conduction can also be achieved between the stator 30 core and the coolant flowing within the rotor cavity 404 through the inner wall of the rotor cavity 404. Furthermore, thermally conductive resin is filled at the upper and lower ends of the stator 30, which fixes and enhances the heat dissipation capacity of the stator 30. The rotor 20 is housed within the rotor cavity 404 of the pump body and surrounded by the flowing coolant, whose heat is carried away by the coolant.

[0033] The specific structure of rotor 20 in this embodiment is as follows: Figure 5 As shown, the rotor 20 is a cylindrical support 201. The cylinder is open at one end facing the suction inlet, and has a bottom wall 205 at the other end. A permanent magnet 204 is fixed to the inner wall of the cylinder. A through hole 206 is located at the center of the bottom wall 205. The outer edge of the through hole 206 protrudes axially outward from the cylindrical support, forming a hollow columnar protrusion. This protrusion forms a bearing support 207. A bearing 208 is fixedly installed inside the bearing support 207. Several side through holes 209 are radially opened in the lower section of the inner wall of the bearing support 207 to guide the coolant flowing in through the through holes 206 to the impeller area. On the upper end face of the bottom wall 205, an impeller 202 for driving the coolant is fixedly installed outside the bearing support 207. The impeller 202 is fixedly connected to the bottom wall of the support 201, thus forming the outer rotor of the motor. The fixed connection can be achieved using conventional processes such as ultrasonic welding or threaded connection. Figure 6 The rotor 20 shown is Figure 5 In a modified design of the embodiment, several side through holes 209 are opened in the connection area between the bottom wall 205 and the bearing support 207. This structure increases the axial length of the bearing support 207 and the bearing 208, which can improve the rotational stability of the rotor 20. Figure 7 The rotor 20 shown is Figure 5 In another variation of the embodiment, the support 201 is a plastic part, integrally injection molded with the permanent magnet 204 or the bearing 208 as inserts. This structure simplifies the installation process of the rotor 20 and ensures that the parts are firmly connected.

[0034] After assembly, the rotor 20 is mounted on the spindle 103 via bearing 208 and supported in the rotor cavity 404 of the pump body 40. The rotor 20 and stator 30 together form an electric motor. The rotor 20 is driven to rotate by the rotating magnetic field generated by the stator 30. The impeller 202, which is fixed to the upper end of its bottom wall, rotates around the spindle 103 via bearing 208, creating pressure in the pump body volute 102. This allows the coolant to flow smoothly. Figure 3 As indicated by the large arrow, it is input through the inlet 402 and output through the outlet 101.

[0035] Further design optimizations, such as Figure 2 , Figure 3 As shown, several return holes 203 are provided at the top of the cylindrical wall of the support 201. Preferably, the center line of the return holes 203 is located at the junction of the cylindrical wall and the bottom wall. The annular gap between the outer wall of the pump body rotor cavity 404 and the cylindrical support 201 is set as an inlet 4041 for cooling the motor section. Therefore, as Figure 3 As indicated by the small arrow, the coolant circulates from the high-pressure side of the pump section volute through the inlet 4041 to the gap between the cylindrical support 201 and the inner wall of the rotor cavity 404, and finally flows back to the volute through the return hole 203 and is driven out by the impeller. This forms a flow channel for the coolant to surround the rotor 20, and the heat of the rotor 20 is carried away by the flowing coolant, resulting in strong heat dissipation capacity.

[0036] Furthermore, the electric pump also includes a control board 50 located at the opening end of the stator cavity 403, below the stator 30. The control board 50 is electrically connected to the stator 30 to control the operation of the motor. It can be connected to an external power source via a flexible wire, or... Figure 1 As shown, the connection to an external power source is achieved through a plug-in connector integrally injection molded with the pump body. Preferably, the heating power element on the control board 50 is in direct or close contact with the wall of the inlet pipe 401 via a heat-conducting component or by filling the gap between them with thermally conductive silicone grease. The heat generated by the power element is carried away by the coolant flowing inside the inlet pipe 401. The heat-conducting component specifically refers to a structural component made of a metal material with high thermal conductivity, such as aluminum, that can be fitted and installed to fit the shape of the power element and the inlet pipe 401. The electric pump also includes a rear cover plate 60 that covers the control board 50 and the stator 30 on one side of the stator cavity 403 with the pump body flange. Preferably, the rear cover plate 60 is provided with an elastic seal at the contact point with the pump body to prevent dust and moisture from entering the interior of the stator 30.

[0037] Figure 8This diagram shows an axial cross-sectional view of Embodiment 2 of the shielded electric pump driven by an external rotor motor for conveying coolant according to the present invention. Embodiment 2 differs from Embodiment 1 in that: the spindle 103 is fixed at the center of the rotor 20; a bearing 208 is fixedly installed in the countersunk hole at the center of the pump cover 10, and the bearing 208 can be integrally injection molded with the pump cover, or fixed to the pump cover by different methods such as interference fit, hot melt welding, or bonding; a second bearing 406 is fixedly installed in the support seat 405 of the inlet pipe. During assembly, the rotor 20 is supported and limited by the spindle 103 fitting into the second bearing 406 and the bearing 208, and is housed in the rotor cavity 404 of the pump body 40. The rotor 20 and the stator 30 together form an electric motor. The rotor 20 is driven to rotate by the magnetic field generated by the stator 30, driving the impeller 202, which is fixed to the upper end of the rotor bottom wall, to rotate along with the spindle 103, creating pressure in the pump body volute 102, thereby allowing the coolant to be conveyed as described above. Figure 3 As indicated by the large arrow, it is input through the inlet 402 and output through the outlet 101.

[0038] Figure 9 This embodiment shows the specific structure of the rotor 20, which is different from that in Embodiment 1. Figure 5 The main difference in the rotor is that the outer edge of the central through hole 206 in the bottom wall 205 protrudes axially outward from the cylindrical support to form a columnar protrusion, which becomes the spindle support 210. The spindle 103 is fixedly mounted in the center of the spindle support 210. Several side through holes 209 are radially opened in the lower section of the inner cavity wall of the spindle support 210 to guide the coolant flowing in through the through holes 206 to the impeller flow channel. The spindle 103 and the spindle support 210 can be fixed by conventional processes such as thermoforming welding, interference fit, or integral injection molding.

[0039] The embodiments and design examples described above are merely illustrative of several implementations of the present invention, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of protection of the present invention. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention. For example, the mandrel 103 can be fixed to the pump body 40, and a support seat can be provided at the center of the pump cover. When the pump body and pump cover are closed and fixed, the other end of the mandrel 103 is fitted into the pump cover support seat and supported. These all fall within the scope of protection of the present invention.

Claims

1. A canned motor-driven electric pump for conveying coolant, comprising: The pump cover (10), pump body (40), and the volute (102) enclosed by the two are characterized in that they further include: —The pump body (40) has an inlet pipe (401) at its center that connects to the external coolant. The inlet pipe (401) is connected to the suction side of the volute (102) along the axis of the volute (102) and has an opening facing downward. The inlet pipe (401) passes through the center of the stator (30) of the external rotor motor. —A spindle (103) supporting the impeller is set between the inlet pipe (401) of the pump cover (10) and the pump body (40) along the axis of the volute (102). —A cylindrical stator cavity (403) surrounding the inlet pipe (401) and with part of the periphery of the inlet pipe (401) as the inner cavity wall and the opening facing downwards, and a stator (30) of an external rotor motor housed in the stator cavity (403), wherein the inner and outer peripheries of the stator (30) of the external rotor motor are in thermal contact with the inner and outer cavity walls of the stator cavity (403) respectively, and the inner and outer peripheries of the core of the stator (30) can be thermally conducted with the flowing coolant; —A cylindrical rotor cavity (404) surrounding the stator cavity (403) and opening upward through the volute (102) is used to house the rotor (20) of the external rotor motor. The inner and outer circumferences of the rotor (20) can conduct heat with the flowing coolant. The inlet pipe (401), stator cavity (403) and rotor cavity (404) are integrally injection molded and have a concave-convex shape in cross-section along the axis.

2. The shielded electric pump driven by an external rotor motor for conveying coolant according to claim 1, characterized in that, One end of the inlet pipe (401) is provided with a suction port (402) for inputting coolant, and the other end of the pipe (102) is provided with a support seat (405) for supporting the spindle (103). The connection between the support seat (405) and the inlet pipe wall is provided with several inlet pipe through holes (4051) for connecting the volute (102).

3. The shielded electric pump driven by an external rotor motor for conveying coolant according to claim 1, characterized in that, The rotor (20) has a cylindrical support (201) with a bottom wall (205) at one end and an open end at the other. A permanent magnet (204) is fixed on the cylindrical inner surface. A through hole (206) is provided in the center of the bottom wall (205). The outer edge of the through hole (206) protrudes axially outward from the cylinder to form a protrusion that defines the spindle (103). An impeller (202) that drives the coolant is fixed on the upper surface of the bottom wall (205) around the protrusion. Several side through holes (209) are opened at the junction of the protrusion and the bottom wall (205) to guide the coolant flowing into the through hole (206) to the impeller flow channel.

4. The shielded electric pump driven by an external rotor motor for conveying coolant according to claim 3, characterized in that, The top of the cylindrical wall of the bracket (201) is provided with several reflux holes (203).

5. The shielded electric pump driven by an external rotor motor for conveying coolant according to claim 4, characterized in that, The centerline of the reflux hole (203) is located at the junction of the cylindrical wall and the bottom wall.

6. The shielded electric pump driven by an external rotor motor for conveying coolant according to any one of claims 1-5, characterized in that, It also includes a control board (50) disposed at the opening end of the stator cavity (403) and a plug integrally injection molded with the pump body for detachable electrical connection with an external power source, wherein the control board is electrically connected to the plug.

7. The shielded electric pump driven by an external rotor motor for conveying coolant according to claim 6, characterized in that, The heating power element on the control board (50) is in direct or through a heat-conducting component in thermal contact with the inlet pipe (401).

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