Electric water pump, assembly method of electric water pump and new energy vehicle

Abstract

The present invention discloses an electric water pump, an assembly method of the electric water pump and a new energy vehicle, which include a pump cover, a pump housing, a shaft core, a rotor assembly, a drive circuit board, an end cover and a stator assembly; the buckle part of the thrust washer is correspondingly buckled in the buckle installation groove to fixedly attach the main circular ring part of the thrust washer to the end face of the thrust washer mounting seat; the axial length of the sintered ferrite magnetic ring is L1, the bearing and the sintered ferrite magnetic ring have an overlapping part L2 in its axial direction, and the distance between the bearing and the blade is L3, then L1 / 4 ≤ L2 ≤ L1 / 5, and, L2 ≤ 3.0 mm; a metal fixing member fixes the drive circuit board in the pump housing, and the grounding post on the end cover contacts the metal fixing member on the drive circuit board to complete the grounding of the end cover. The electric water pump of the present invention has the advantages of easy assembly, high pump cover life, good EMC performance and good magnetic conductance performance of the rotor assembly.

Description

Technical Field

[0001] The present invention relates to the technical field of electronic water pumps, and particularly to an electronic water pump, an assembly method thereof, and a new energy vehicle. Background Art

[0002] The interior of an electronic water pump includes a series of precision components such as a stator assembly, a rotor assembly, an impeller, and a drive circuit board carrying a main control and power electronic devices, enabling the electronic water pump to have a high output efficiency and achieve precise flow control. Based on the above structure, electronic water pumps are widely used in automobiles, household appliances, and industrial equipment. In particular, new energy vehicles usually have two or more electronic water pumps. The electronic water pump is the power source of the entire cooling system of a new energy vehicle. The power battery, drive motor, etc. of a new energy vehicle all rely on the electronic water pump to drive the coolant to circulate and cool.

[0003] In order to enable the electronic water pump to have good performance and stability, at least the following problems need to be considered:

[0004] 1. The high-speed operation of the rotor assembly will cause the pressure at the impeller to decrease, resulting in a pressure difference on both sides of the rotor assembly. At this time, the rotor assembly will move towards the pump cover, causing friction between the rotor assembly and the pump cover. Moreover, since the pump cover is an integrally formed workpiece, the friction between the rotor assembly and the pump cover is extremely likely to reduce the service life of the electronic water pump. Therefore, a reasonable thrust washer and its installation structure need to be provided for the electronic water pump to improve the service life of the electronic water pump and reduce the cost and assembly difficulty of the electronic water pump;

[0005] 2. The drive circuit board is the driving and control core of the electronic water pump. Since the main control and power electronic devices are carried on the drive circuit board, the drive circuit board has high requirements for EMC performance. In order to ensure the reliable operation of the drive circuit board, the electromagnetic interference during the operation of the drive circuit board should be minimized as much as possible. Therefore, the end cover must be grounded. In addition, grounding the end cover can also prevent the electromagnetic interference radiated by the end cover from affecting the operation of power components such as the power battery and drive motor of the new energy vehicle. Therefore, a low-cost and easy-to-assemble end cover grounding structure needs to be provided for the electronic water pump to improve the EMC performance of the electronic water pump;

[0006] 3. Considering the manufacturability and reliability of the rotor assembly, the material of the rotor permanent magnet is generally plastic magnet or sintered rare earth permanent magnet material. The plastic magnet ring is used for integral plastic coating, which has no risk of rusting and good reliability. However, the magnetic performance of the plastic magnet material is relatively low. To meet the performance requirements, the size and volume of the motor need to be increased. Using sintered rare earth permanent magnet material is expensive, and an additional rotor core is required to install the permanent magnet and magnetic conduction. Moreover, water-proof components need to be installed on the outer ring of the rotor core to prevent the rotor core and permanent magnet from being immersed in water and rusting. The water-proof components will increase the air gap of the motor and reduce the motor performance. Therefore, a good rotor assembly structure needs to be provided for the electronic water pump. Summary of the Invention

[0007] One of the purposes of the present invention is to provide an electronic water pump, which has the advantages of easy assembly, high pump cover life, good EMC performance, and good magnetic conductance performance of the rotor assembly.

[0008] Another purpose of the present invention is to provide an assembly method for an electronic water pump, which makes the above-mentioned electronic water pump easy to assemble.

[0009] Another purpose of the present invention is to provide a new energy vehicle, which has an electronic water pump with good EMC performance, low cost, and easy assembly.

[0010] To achieve the above purposes, the present invention provides the following technical solutions: An electronic water pump, characterized in that it includes a pump cover, a pump housing, a shaft core, a rotor assembly, a drive circuit board, an end cover, and a stator assembly;

[0011] The pump cover includes a pump cover body and a thrust washer; an inlet channel and an outlet channel communicating with its inside and outside are formed on the pump cover body. A thrust washer mounting seat is provided inside the pump cover body, and a snap mounting groove is provided at the end face of the thrust washer mounting seat; the thrust washer includes a main circular ring part, and at least two snap parts integrally formed on the main circular ring part; the snap parts of the thrust washer are correspondingly snapped into the snap mounting grooves of the thrust washer mounting seat to fixedly attach the main circular ring part of the thrust washer to the end face of the thrust washer mounting seat;

[0012] The rotor assembly includes: a cylindrical bracket, an installation hole is provided along its axial direction, a circular installation position is provided along its circumferential direction, and a blade is provided at one end of the cylindrical bracket;

[0013] A bearing is arranged in the installation hole, and its axis coincides with the axis of the cylindrical bracket;

[0014] An impeller cover is fixedly connected to the end of the cylindrical bracket and covers the blade;

[0015] A sintered ferrite magnetic ring is disposed on the installation position. Define the axial length of the sintered ferrite magnetic ring as L1. The bearing and the sintered ferrite magnetic ring have an overlapping part in their axial directions, and define this overlapping part as L2. The distance between the bearing and the blade is L3. Further, the relationship among L1, L2, and L3 satisfies L1 / 5 ≤ L2 ≤ L1 / 4, and L2 ≤ 3.0 mm.

[0016] A rotor chamber is formed inside the pump housing. The pump cover body and the pump housing are joined and fixed to each other, so that an impeller chamber is formed inside the pump cover body. The shaft core is arranged axially along the rotor chamber and the impeller chamber and is fixed in the rotor chamber and the impeller chamber.

[0017] The rotor assembly is supported by the shaft core in the space enclosed by the pump cover body and the pump housing, so that the sintered ferrite magnetic ring is located in the rotor chamber, and the blade and the impeller cover are located in the impeller chamber. The stator assembly is arranged in the pump housing and arranged around the rotor chamber, so that the stator assembly can magnetically couple and drive the rotor assembly to rotate.

[0018] When the rotor assembly rotates, at least a part of it is in contact with the thrust washer.

[0019] The drive circuit board is accommodated and fixed on one side of the pump housing relative to the pump cover, and the drive circuit board is electrically connected to the stator assembly. The end cover is fixed at one end of the pump housing relative to the pump cover, and the pump housing is closed by the end cover, thereby sealing the stator assembly and the drive circuit board.

[0020] The drive circuit board is fixed in the pump housing by at least one metal fixing member, and the metal fixing member is electrically connected to the negative electrode and / or the ground electrode of the drive circuit board through the printed circuit on the drive circuit board, so that the metal fixing member is grounded.

[0021] The end cover is integrally provided with a grounding post.

[0022] After the electronic water pump is assembled, the metal fixing member fixes the drive circuit board in the pump housing, and the grounding post on the end cover is in contact with the metal fixing member on the drive circuit board to complete the grounding of the end cover.

[0023] An assembly method of an electronic water pump for assembling the above-mentioned electronic water pump includes:

[0024] Processing the end cover: integrally process the grounding post on the end cover.

[0025] Assembling the pump cover: Align the respective snap portions of the formed thrust washer with the snap mounting grooves of the thrust washer mounting seat of the pump cover body. Press the main circular ring portion of the thrust washer so that the respective snap portions enter the snap mounting grooves correspondingly until the main circular ring portion of the thrust washer abuts against the end face of the thrust washer mounting seat;

[0026] Assembling the rotor assembly: By means of in-mold injection molding, form the cylindrical bracket with blades on the bearing and the sintered ferrite magnet ring, such that the bearing and the sintered ferrite magnet ring have overlapping portions in their axial directions, and fix the impeller cover to the end of the cylindrical bracket by means of ultrasonic welding;

[0027] Overall assembly: Weld the phase pole pins of the stator assembly to the drive circuit board. Then, install the stator assembly and the drive circuit board together into the pump housing, with the stator assembly disposed around the rotor chamber. The drive circuit board is fixed in the pump housing by at least one metal fixing member, and the metal fixing member is electrically connected to the negative electrode and / or the ground electrode of the drive circuit board through the printed circuit on the drive circuit board, grounding the metal fixing member. Fix the end cover to one end of the pump housing, and seal the pump housing through the end cover to thereby seal the stator assembly and the drive circuit board. Also, make the grounding post on the end cover contact the metal fixing member on the drive circuit board to complete the grounding of the end cover. Fix one end of the shaft core in the rotor chamber, slip the bearing of the rotor assembly onto the shaft core, and fix the pump cover body to the other end of the pump housing to thereby cover the rotor assembly, such that at least a part of the rotor assembly contacts the thrust washer during rotation, and fix the other end of the shaft core to the pump cover body.

[0028] A new energy vehicle that applies the above-mentioned electronic water pump.

[0029] Compared with the prior art, the beneficial effects of the present invention are:

[0030] 1. For the electric water pump of the present invention, the buckle part of the thrust washer is correspondingly buckled in the buckle installation groove of the thrust washer mounting seat. This fixing structure makes it difficult for the thrust washer to fall off the thrust washer mounting seat, improving the reliability of the thrust washer installation. At the same time, this structure reduces the cost of the thrust washer itself, and there is no need for precise positioning of the thrust washer during installation, nor is it necessary to adopt costly processes such as in-mold injection. Therefore, it also improves its assembly efficiency and reduces its assembly cost. The grounding post metal fixing parts integrally provided on the end cover are in contact with each other, enabling the end cover to be electrically connected to the negative pole and / or the grounding pole of the drive circuit board, achieving reliable grounding of the end cover. By using one metal fixing part to simultaneously fix the drive circuit board and complete the grounding of the end cover, and there is no need to set other conducting parts on the drive circuit board. Compared with setting an independent intermediate connecting part, integrally setting the grounding post on the end cover can effectively simplify the end cover grounding structure, with lower requirements for the number, manufacturing precision, and assembly precision of components, and effectively reducing the cost of the end cover grounding structure. In addition, integrally setting the grounding post on the end cover, in cooperation with the metal fixing part that can be used as a fastener for the drive circuit board, even in a vibrating environment or during long-term use, the two are not easily displaced from each other. Through the injection molding process, the sintered ferrite magnetic ring and the shaft sleeve are molded into an integral structure, which has small structural dimensions, simple manufacturing processes, and low material costs. And further, the magnetic ring is made of sintered ferrite material, which not only has low material costs but also has advantages such as high reliable performance. After the present invention adopts the sintered ferrite magnetic ring, the air gap of the motor, the stator stack thickness, and the magnetic ring thickness are effectively reduced, and the motor efficiency is still significantly improved, reducing the material costs of the stator and rotor. And after adopting the sintered ferrite magnetic ring, the stator punching still does not show the phenomenon of magnetic circuit saturation, but instead, the motor performance has a certain improvement. When the axial position of the bearing satisfies the above relationship, its stress state is the best, the forces on both ends of the inner ring of the bearing are relatively small, and the forces on other parts are evenly distributed, which can effectively improve the wear of the sliding bearing and increase the service life and reliability of the sliding bearing.

[0031] 2. The new energy vehicle of the present invention has an electric water pump with good EMC performance, low cost, and easy assembly, which can effectively cool heat-generating components such as power batteries and drive motors. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1 One of the overall structural views of Embodiment 1 of the present invention.

[0033] Figure 2 Another overall structural view of Embodiment 1 of the present invention.

[0034] Figure 3 The structural view of the pump cover body in Embodiment 1 of the present invention.

[0035] Figure 4 It is a sectional structure view of the pump cover body in the first embodiment of the present invention.

[0036] Figure 5 It is a structure view of the thrust washer in the first embodiment of the present invention.

[0037] Figure 6 It is Figure 5 the sectional view in the A-A direction in

[0038] Figure 7 It is a sectional structure view of the first embodiment of the present invention.

[0039] Figure 8 It is Figure 7 the enlarged view of part B in

[0040] Figure 9 It is a structure view of the rotor assembly in the first embodiment of the present invention.

[0041] Figure 10 It is a structure view of the sintered ferrite magnetic ring in the first embodiment of the present invention.

[0042] Figure 11 It is Figure 10 the sectional view in the C-C direction in

[0043] Figure 12 It is a sectional structure view of the rotor assembly in the first embodiment of the present invention.

[0044] Figure 13 It is Figure 12 the sectional view in the D-D direction in

[0045] Figure 14 It is Figure 12 the enlarged view of part E in

[0046] Figure 15 It is a structure view of the sintered ferrite magnetic ring in the first embodiment of the present invention.

[0047] Figure 16 It is a comparison table of the efficiency and structural dimensions of the electronic water pump using different materials in the present invention.

[0048] Figure 17 It is the cloud map of the performance simulation result of the sintered ferrite magnetic ring of the present invention.

[0049] Figure 18 It is a structure view of the end cover in the first embodiment of the present invention.

[0050] Figure 19 It is a sectional structure view of the first embodiment of the present invention.

[0051] Figure 20Schematic diagram of the cooperation between one of the grounding posts and the drive circuit board in Embodiment 1 of the present invention.

[0052] Figure 21 Structural view of one of the grounding posts in Embodiment 1 of the present invention.

[0053] Figure 22 Schematic diagram of the cooperation between another grounding post and the drive circuit board in Embodiment 1 of the present invention.

[0054] Figure 23 Structural view of another grounding post in Embodiment 1 of the present invention.

[0055] Reference numerals: 1, pump cover; 11, pump cover body; 111, thrust washer mounting seat; 112, buckle mounting groove; 113, inner ring part; 114, outer ring part; 115, connecting beam; 116, impeller chamber; 117, water inlet channel; 118, water outlet channel; 12, thrust washer; 121, main body circular part; 122, buckle part; 123, first buckle strip; 124, second buckle strip; 2, pump housing; 21, rotor chamber; 3, shaft core; 4, rotor assembly; 41, cylindrical bracket; 411, mounting hole; 412, mounting position; 413, blade; 414, reinforcing column; 415, body; 416, first end plate; 417, second end plate; 418, flow guiding groove; 42, bearing; 43, impeller cover; 44, sintered ferrite magnetic ring; 441, reinforcing hole; 5, drive circuit board; 51, printed circuit; 52, screw; 521, screw head; 522, screw head groove; 53, contact copper sheet; 6, end cover; 61, grounding post; 7, stator assembly. Detailed implementation manners

[0056] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

[0057] Embodiment 1:

[0058] This embodiment provides an electronic water pump that can drive fluid media such as water, coolant, and oil circuit media to make the fluid media flow directionally.

[0059] Please refer to [[ID=3,0]] Figure 1 and Figure 2 , the electronic water pump of this embodiment includes a pump cover 1, a pump housing 2, a shaft core 3, a rotor assembly 4, a drive circuit board 5, an end cover 6, and a stator assembly 7.

[0060] Among them, the pump cover 1 of this embodiment includes a pump cover body 11 and a thrust washer 12.

[0061] The pump cover body 11 is an integrally formed engineering plastic material or metal material cover body. An inlet channel 117 and an outlet channel 118 that communicate the inside and outside of the pump cover body 11 are formed on the pump cover body 11. A thrust washer mounting seat 111 is provided inside the pump cover body 11, and a buckle mounting groove 112 is provided at the end face of the thrust washer mounting seat 111.

[0062] The thrust washer 12 includes a main body ring part 121 and at least two buckle parts 122 integrally formed on the main body ring part 121. In this embodiment, three buckle parts 122 are uniformly arranged along the circumferential direction of the main body ring part 121. Correspondingly, three buckle mounting grooves 112 are also uniformly arranged at the end face of the thrust washer mounting seat 111.

[0063] The buckle parts 122 of the thrust washer 12 are correspondingly buckled into the buckle mounting grooves 112 of the thrust washer mounting seat 111 to fixedly attach the main body ring part 121 of the thrust washer 12 to the end face of the thrust washer mounting seat 111.

[0064] Please refer to Figure 3 and Figure 4 , the thrust washer mounting seat 111 includes a coaxial inner ring part 113 and an outer ring part 114. The inner ring part 113 and the outer ring part 114 are connected by a connecting beam 115. In fact, the inner ring part 113, the outer ring part 114, and the connecting beam 115 are all integrally formed, thus constituting a complete thrust washer mounting seat 111. The space surrounded by the outer wall of the inner ring part 113, the inner wall of the outer ring part 114, and two adjacent connecting beams 115 is the buckle mounting groove 112. It can be seen from this that the buckle mounting groove 112 is a through groove structure with both ends penetrating. The main body ring part 121 of the thrust washer 12 is at least fixedly attached to the end face of the inner ring part 113. In this embodiment, the main body ring part 121 of the thrust washer 12 is only attached to the end face of the inner ring part 113. In other embodiments, after the main body ring part 121 of the thrust washer 12 extends radially, it can be simultaneously attached to the end faces of the inner ring part 113 and the outer ring part 114.

[0065] Please refer to Figure 5 and Figure 6, the buckle portion 122 of the thrust washer 12 includes a first buckle strip 123 and a second buckle strip 124; one end of the first buckle strip 123 is connected to the main body ring portion 121, and the other end of the first buckle strip 123 is connected to the second buckle strip 124; the first buckle strip 123 extends axially away from the main body ring portion 121 starting from the main body ring portion 121, and the second buckle strip 124 folds back from the position where it is connected to the first buckle strip 123 and extends towards the direction close to the main body ring portion 121; in this way, the buckle portion 122 forms a "V" - shaped structure.

[0066] It should be noted that the thrust washer 12 is made of a thin metal plate through a stamping process, that is, both the first buckle strip 123 and the second buckle strip 124 of the buckle portion 122 are formed by bending with a stamping die, and the inner hole of the main body ring portion 121 is formed by a blanking process.

[0067] In some possible embodiments, the thrust washer mounting seat 111 is also the shaft core bracket on the pump cover 1; the shaft core 3 of the electric water pump can be inserted into the inner hole of the inner ring portion 113 of the thrust washer mounting seat 111 after passing through the inner hole of the main body ring portion 121 of the thrust washer 12.

[0068] Please refer to Figure 6 , further, the axial height of the first buckle strip 123 of the thrust washer 12 is H1, and the axial height of the second buckle strip 124 of the thrust washer 12 is H2, then: H2 - H1 > 0.5 mm; this dimensional relationship can effectively ensure that the buckle portion 122 of the thrust washer 12 can be reliably buckled in the buckle installation groove 112 of the thrust washer mounting seat 111 and is not easily disengaged.

[0069] Please refer to Figure 4 , Figure 6 , Figure 7 and Figure 8 , further, the included angle between the first buckle strip 123 of the buckle portion 122 and the main body ring portion 121 is α, then: 70° ≤ α ≤ 105°.

[0070] On the above basis, the minimum radial distance between the first buckle strip 123 and the center point of the main body ring portion 121 is R, the maximum radial distance between the end of the second buckle strip 124 and the center point of the main body ring portion 121 is B, the inner diameter of the buckle installation groove 112 (i.e., the outer diameter of the inner ring portion 113) is D1, and the outer diameter of the buckle installation groove 112 (i.e., the inner diameter of the outer ring portion 114) is D2, then:

[0071] When 90° ≤ α ≤ 105°, there is At this time, the end of the second snap strip 124 contacts the inner wall of the outer ring portion 114, and after the end of the second snap strip 124 deforms, it exerts a rebounding force on the inner wall of the outer ring portion 114; through this rebounding force, a large frictional force is generated between the second snap strip 124 of the thrust washer 12 and the snap-in mounting groove 112 of the thrust washer mounting seat 111, which can effectively prevent the axial detachment of the thrust washer 12.

[0072] When 75° ≤ α ≤ 90°, there is At this time, the end of the second snap strip 124 contacts the inner wall of the outer ring portion 114, and after the end of the second snap strip 124 deforms, it exerts a rebounding force on the inner wall of the outer ring portion 114; through this rebounding force, a large frictional force is generated between the second snap strip 124 of the thrust washer 12 and the snap-in mounting groove 112 of the thrust washer mounting seat 111, which can effectively prevent the axial detachment of the thrust washer 12; meanwhile, the first snap strip 123 also tightly holds the outer wall of the inner ring portion 113, and through this holding force, a large frictional force is also generated between the first snap strip 123 and the snap-in mounting groove 112 of the thrust washer mounting seat 111, which can further prevent the axial detachment of the thrust washer 12.

[0073] Please refer to Figures 9 - 14 , the rotor assembly 4 includes a cylindrical bracket 41, a bearing 42, an impeller cover 43, and a sintered ferrite magnet ring 44. Among them, an installation hole 411 is provided along the axial direction of the cylindrical bracket 41, an annular installation position 412 is provided along the circumferential direction of the cylindrical bracket 41, and a blade 413 is provided at one end of the cylindrical bracket 41; among them, the bearing 42 is arranged in the installation hole 411, and its axis coincides with the axis of the cylindrical bracket 41; among them, the impeller cover 43 is fixedly connected to the end of the cylindrical bracket 41 and covers the blade 413; among them, the sintered ferrite magnet ring 44 is arranged on the installation position 412, and the cylindrical bracket 41 integrally plastics the sintered ferrite magnet ring 44 and the bearing 42 through an injection molding process.

[0074] Furthermore, the injection molding material is a resinous material. Specifically, using a resinous material can ensure the stability and service life of the cylindrical bracket 41 after molding, and can ensure the production cost.

[0075] Specifically, integrally plastics the sintered ferrite magnet ring 44 and the bearing 42 through an injection molding process, which has the advantages of small structural size, simple manufacturing process, and low material cost; and furthermore, the magnet ring is made of sintered ferrite material, which has the advantages of low material cost and high reliable performance while in use.

[0076] Furthermore, as Figure 16As shown, after the sintered ferrite magnetic ring 44 is adopted in the present invention, the air gap, stator stack thickness and magnetic ring thickness of the motor are effectively reduced, and the motor efficiency is still significantly improved, reducing the material costs of the stator and rotor. Further, Figure 17 This is the electromagnetic performance simulation effect diagram of the present invention. It can be seen from this effect diagram that after the sintered ferrite magnetic ring 44 is adopted, the magnetic saturation of the stator punching sheet does not occur, but the performance of the motor is improved to a certain extent.

[0077] In another embodiment of the present invention, as Figure 12 shown, the axial length of the sintered ferrite magnetic ring 44 is defined as L1. The bearing 42 and the sintered ferrite magnetic ring 44 have an overlapping part in their axial directions. For the convenience of description, this overlapping part is defined as L2; the distance between the bearing 42 and the blade 413 is L3; further, the relationship among L1, L2 and L3 satisfies L1 / 5 ≤ L2 ≤ L1 / 4, and L2 ≤ 3.0 mm. Specifically, when the axial position of the bearing 42 satisfies the above relationship, its stress state is the best, the forces on both ends of the inner ring of the bearing 42 are relatively small, and the force distribution of other parts is uniform, which can effectively improve the wear of the sliding bearing 42 and improve the service life and reliability of the sliding bearing 42;

[0078] In another embodiment of the present invention, the number of magnetic poles of the sintered ferrite magnetic ring 44 is N, and reinforcing holes 441 adapted to the number of magnetic poles are provided on both side surfaces of the sintered ferrite magnetic ring 44, that is, the number of reinforcing holes 441 on each side surface is N. It should be noted that N here represents the quantity, and this quantity is an integer. This quantity can be one or multiple, and no limitation is made here. Further, the axes of the respective reinforcing holes 441 are parallel to the axis of the sintered ferrite magnetic ring 44; the cylindrical bracket 41 is provided with reinforcing columns 414 corresponding to the respective reinforcing holes 441 one by one, and the reinforcing columns 414 are filled in the reinforcing holes 441. Specifically, the provided reinforcing holes 441 and reinforcing columns 414 cooperate with each other, and the reinforcing columns 414 are filled in the reinforcing holes 441, which can prevent the radial detachment of the sintered ferrite magnetic ring 44, avoid the rotor from being stuck and not rotating, and ensure the normal operation of the electronic water pump.

[0079] In another embodiment of the present invention, as Figures 9 - 12As shown, the reinforcement holes 441 corresponding to the magnetic poles are all located in the middle of the magnetic poles. Furthermore, the interface of each reinforcement hole 441 can be of any shape, including but not limited to circular, elliptical, polygonal and other irregular shapes; the depth of the reinforcement hole 441 is defined as H, and the depth H of the reinforcement hole 441 and the axial length L1 of the sintered ferrite ring 44 and the distance L3 between the shaft and the blade 413 satisfy 0.2mm≤H, and H≤L1 / L3; only when the above relationship is met can the reinforcement hole 441 play a reinforcing role without affecting the performance of the sintered ferrite ring 44. Otherwise, if the above relationship is not met, the electromagnetic performance will be reduced or there will be no fixing effect.

[0080] In another embodiment of the present invention, Figure 9 、 Figure 13 and Figure 15 As shown, the cylindrical bracket 41 includes a body 415, one end of the body 415 is provided with a first end plate 416 extending radially therefrom, and the side of the body 415 is provided with a second end plate 417 extending radially therefrom, and an annular groove-shaped mounting position 412 is formed between the first end plate 416 and the second end plate 417, that is, the sintered ferrite magnetic ring 44 is arranged between the first end plate 416 and the second end plate 417, and each reinforcement column 414 is arranged on the side opposite to the first end plate 416 and the second end plate 417 along the circumference of the cylindrical bracket 41, and further, the first end plate 416 and the second end plate 417 are provided. The diameters D2 of the two end plates 417 are the same, and the diameter D1 of the sintered ferrite ring 44 is smaller than the diameters D2 of the first end plate 416 and the second end plate 417; specifically, since the present invention adopts an injection molding process to plastic-coat the sintered ferrite ring 44 and the bearing 42 into an integrated structure, therefore, when the diameter D1 of the sintered ferrite ring 44 is smaller than the diameters D2 of the first end plate 416 and the second end plate 417, it can be ensured that there is no injection molding material on the outer cylindrical surface of the sintered ferrite ring 44, thereby reducing the air gap requirements between the stator and the rotor, so as to improve the performance efficiency of the motor.

[0081] In another embodiment of the present invention, Figures 9 - 15 As shown, the cylindrical bracket 41 is also provided with a guide groove 418, which is arranged on the mounting position 412 along the circumference of the cylindrical bracket 41, and the opening of each guide groove 418 faces the inner circular surface of the sintered ferrite magnetic ring 44, that is, when the sintered ferrite magnetic ring 44 is set at the mounting position 412, a guide hole is formed between the inner circular surface of the sintered ferrite magnetic ring 44 and the guide groove 418; one end of the guide groove 418 passes through the first end plate 416; specifically, arranging the guide groove 418 in a limited size space can improve the fluidity of the medium and increase the heat dissipation performance of the motor. In addition, the set guide groove 418 can also increase the size of the molding guide pin of the injection mold and improve the life of the mold.

[0082] The pump housing 2 is an integrally formed open half housing made of engineering plastic or metal, and its shape matches that of the pump cover 1; the shaft core 3 is a cylindrical metal shaft body with a smooth surface, suitable as a support shaft; the stator assembly 7 is an annular coil assembly, and after the stator assembly 7 is energized, a rotating magnetic field can be generated in its inner ring; the drive circuit board 5 is based on a printed circuit board (PCB), on which a main control (MCU), power electronic devices, and corresponding printed circuits and peripheral components are mounted, for receiving electrical energy and control signals and driving the stator assembly 7 to operate; the end cover 6 is a round plate-shaped cover body made of metal, and its material is preferably aluminum alloy or stainless steel. In fact, the end cover 6 should have good electrical conductivity.

[0083] A rotor chamber 21 is formed inside the pump housing 2. Specifically, one end of the pump housing 2 sinks to form an open cylindrical chamber, and this chamber is the rotor chamber 21; the pump cover 1 and the pump housing 2 are joined and fixed to each other, so that an impeller chamber 116 is formed inside the pump cover 1, and the rotor chamber 21 and the impeller chamber 116 communicate with each other; the shaft core 3 is arranged along the axial direction of the rotor chamber 21 and the impeller chamber 116 and is fixed in the rotor chamber 21 and the impeller chamber 116.

[0084] The rotor assembly 4 is supported by the shaft core 3 in the space enclosed by the pump cover 1 and the pump housing 2, so that the sintered ferrite magnetic ring 44 is located in the rotor chamber 21, and the blades 413 and the impeller cover 43 are located in the impeller chamber 116. Specifically, the bearing 42 of the rotor assembly 4 is sleeved on the shaft core 3, so that the shaft core 3 can support the entire rotor assembly 4; the stator assembly 7 is arranged in the pump housing 2 and surrounds the rotor chamber 21, so that the stator assembly 7 can magnetically couple and drive the rotor assembly 4 to rotate. In fact, the stator assembly 7 is fixed outside the rotor chamber 21 by means of adhesive fixation or interference fit; the drive circuit board 5 is accommodated on one side of the pump housing 2 relative to the pump cover 1, and the drive circuit board 5 is electrically connected to the stator assembly 7, and the end cover 6 is fixed at one end of the pump housing 2 relative to the pump cover 1, and the pump housing 2 is closed by the end cover 6, thereby sealing the stator assembly 7 and the drive circuit board 5.

[0085] It should be noted that when the rotor assembly 4 rotates, at least a part of it is in contact with the thrust washer 12. In this embodiment, specifically, one end of the bearing 42 is in contact with the thrust washer 12.

[0086] The drive circuit board 5 is fixed in the pump housing 2 by at least one metal fixing member, and the metal fixing member is electrically connected to the negative electrode and / or the ground electrode of the drive circuit board 5 through the printed circuit 51 on the drive circuit board 5, so that the metal fixing member is grounded; please refer to Figure 18, a grounding post 61 is integrally provided on the inner side of the end cover 6. Specifically, the grounding post 61 is integrally die-cast with the main body 415 of the end cover 6, or the grounding post 61 is machined on the end cover 6 by milling; after the electronic water pump is assembled, the metal fixing member fixes the driving circuit board 5 in the pump housing 2, and the grounding post 61 on the end cover 6 contacts the metal fixing member on the driving circuit board 5 to complete the grounding of the end cover 6.

[0087] Please refer to Figure 19 , specifically, the metal fixing member is a screw 52 for fixing the driving circuit board 5 in the structure of the electronic water pump; obviously, there is more than one screw 52 for fixing the driving circuit board 5, but in this embodiment, only one screw 52 serves as the grounding component, and the remaining screws 52 are only used to fix the driving circuit board 5; the driving circuit board 5 is provided with a printed circuit 51 electrically connected to the negative electrode and / or the grounding electrode of the driving circuit board 5 at the screw hole of the screw 52. In fact, the printed circuit 51 can be arranged around the screw hole or penetrate the screw hole; after the electronic water pump is assembled, the screw 52 contacts the printed circuit 51 electrically connected to the negative electrode and / or the grounding electrode of the driving circuit board 5, and the grounding post 61 on the end cover 6 contacts the screw head 521 of the screw 52.

[0088] In the electronic water pump of this embodiment, the integrally provided grounding post 61 on the end cover 6 contacts the metal fixing member, enabling the end cover 6 to be electrically connected to the negative electrode and / or the grounding electrode of the driving circuit board 5, realizing reliable grounding of the end cover 6. A single metal fixing member simultaneously serves to fix the driving circuit board 5 and complete the grounding of the end cover 6, and there is no need to provide other conducting members on the driving circuit board 5; compared with setting an independent intermediate connecting member, integrally setting the grounding post 61 on the end cover 6 can effectively simplify the grounding structure of the end cover 6, with lower requirements for the number, manufacturing precision, and assembly precision of components, and effectively reduce the cost of the grounding structure of the end cover 6; in addition, integrally setting the grounding post 61 on the end cover 6 in cooperation with the metal fixing member that can serve as a fastener for the driving circuit board 5 makes it difficult for the two to become dislocated from each other even in a vibrating environment or during long-term use.

[0089] To increase the contact area between the screw 52 and the printed circuit 51, the driving circuit board 5 is also provided with a contact copper sheet 53 at the screw hole of the screw 52. The contact copper sheet 53 is annular and surrounds the outer periphery of the screw hole. The contact copper sheet 53 is in electrical contact or overlapping setting or integrally set with the printed circuit 51 electrically connected to the negative electrode and / or the grounding electrode of the driving circuit board 5. Specifically, electrical contact means that the contact copper sheet 53 and the printed circuit 51 are connected to each other through a section of circuit, overlapping setting means that the contact copper sheet 53 is stacked on the printed circuit 51 as an independent component, and integrally setting means that the contact copper sheet 53 is arranged on the driving circuit board 5 by printing and serves as a part of the printed circuit 51.

[0090] Further, after the electric water pump is assembled, the grounding post 61 on the end cover 6 applies an axial pressure to the screw head 521 of the screw 52, so that the grounding post 61 on the end cover 6 and the screw head 521 of the screw 52 are in interference fit with each other, improving the tightness when the grounding post 61 on the end cover 6 contacts the screw head 521 of the screw 52, and preventing the grounding post 61 and the screw 52 from being displaced from each other.

[0091] Please refer to Figure 20 and Figure 21 In some possible embodiments, the grounding post 61 of the end cover 6 is in a frustum shape. That is, the diameter of the end of the grounding post 61 is D1, and the diameter of the root of the grounding post 61 is D2, then: D1 < D2; after the electric water pump is assembled, the end of the grounding post 61 and the screw head groove 522 of the screw 52 are in interference fit in the radial direction.

[0092] Please refer to Figure 22 and Figure 23 In other possible embodiments, the grounding post 61 of the end cover 6 is in a conical shape. That is, the diameter of the end of the grounding post 61 is D3, and D3 < 1.5 mm; after the electric water pump is assembled, the end of the grounding post 61 and the bottom of the screw head groove 522 of the screw 52 are in interference fit in the axial direction.

[0093] For the grounding post 61 with the above two structures, during the assembly of the electric water pump, both can be introduced into the screw head groove 522 of the screw 52 through the thinner end, which is beneficial for assembly guidance and reduces the requirement for dimensional tolerance accuracy; in addition, for the above two structures, the end of the grounding post 61 and the screw head groove 522 of the screw 52 are in interference fit with each other, generating a certain deformation, further improving the tightness when the grounding post 61 on the end cover 6 contacts the screw head 521 of the screw 52, and preventing the grounding post 61 and the screw 52 from being displaced from each other.

[0094] Embodiment 2:

[0095] This embodiment provides an assembly method for an electric water pump, which is used to assemble the electric water pump of Embodiment 1.

[0096] The assembly method of the electric water pump in this embodiment includes:

[0097] Machining the end cover 6: integrally machining the grounding post 61 on the end cover 6;

[0098] Assembly of the pump cover 1: Align the respective snap portions 122 of the formed thrust washer 12 with the snap mounting grooves 112 of the thrust washer mounting seat 111 of the pump cover body 11. Press the main circular ring portion 121 of the thrust washer 12 so that the respective snap portions 122 enter the snap mounting grooves 112 until the main circular ring portion 121 of the thrust washer 12 abuts against the end face of the thrust washer mounting seat 111;

[0099] Assembly of the rotor assembly 4: By means of in-mold injection molding, a cylindrical bracket 41 with blades 413 is formed on the bearing 42 and the sintered ferrite magnetic ring 44, such that the bearing 42 and the sintered ferrite magnetic ring 44 have an overlapping portion in their axial directions, and the impeller cover 43 is fixed to the end of the cylindrical bracket 41 by means of ultrasonic welding;

[0100] Overall assembly: Solder the phase pole pins of the stator assembly 7 to the drive circuit board 5. Install the stator assembly 7 and the drive circuit board 5 together into the pump housing 2, such that the stator assembly 7 is disposed around the rotor chamber 21. The drive circuit board 5 is fixed in the pump housing 2 by means of at least one metal fixing member, and the metal fixing member is electrically connected to the negative pole and / or the ground pole of the drive circuit board 5 through the printed circuit 51 on the drive circuit board 5 to ground the metal fixing member. Fix the end cover 6 to one end of the pump housing 2 and enclose the pump housing 2 with the end cover 6 to seal the stator assembly 7 and the drive circuit board 5, and make the ground post 61 on the end cover 6 contact the metal fixing member on the drive circuit board 5 to complete the grounding of the end cover 6. Fix one end of the shaft core 3 in the rotor chamber 21, fit the bearing 42 of the rotor assembly 4 onto the shaft core 3, and fix the pump cover body 11 to the other end of the pump housing 2 to cover the rotor assembly 4, such that at least a part of the rotor assembly 4 contacts the thrust washer 12 during rotation, and fix the other end of the shaft core 3 to the pump cover body 11.

[0101] Embodiment Three:

[0102] This embodiment provides a new energy vehicle that applies the electric water pump described in Embodiment One.

[0103] Through this electric water pump, a power source is provided for the entire cooling system of the new energy vehicle, enabling heat-generating components such as the power battery and the drive motor of the new energy vehicle to drive the coolant to circulate and cool through the electric water pump.

[0104] The new energy vehicle of this embodiment has an electric water pump with good EMC performance, low cost, and easy assembly, and can effectively cool heat-generating components such as the power battery and the drive motor.

[0105] Although embodiments of the present invention have been shown and described, it will be understood by those of ordinary skill in the art that various changes, modifications, substitutions and variations can be made to these embodiments without departing from the principles and spirit of the present invention, and the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. An electronic water pump, characterized in that, It includes a pump cover, a pump housing, a shaft core, a rotor assembly, a drive circuit board, an end cover, and a stator assembly; The pump cover includes a pump cover body and a thrust gasket; an inlet channel and an outlet channel that communicate the inside and outside of the pump cover body are formed on the pump cover body, a thrust gasket mounting seat is provided inside the pump cover body, and a buckle mounting groove is provided at the end face of the thrust gasket mounting seat; the thrust gasket includes a main circular ring portion, and at least two buckle portions integrally formed on the main circular ring portion; the buckle portions of the thrust gasket are correspondingly buckled in the buckle mounting grooves of the thrust gasket mounting seat to fixedly attach the main circular ring portion of the thrust gasket to the end face of the thrust gasket mounting seat; The rotor assembly includes: a cylindrical bracket having a mounting hole axially provided thereon and an annular mounting position circumferentially provided thereon, and a blade provided at one end of the cylindrical bracket; A bearing disposed in the mounting hole, and the axis of the bearing coincides with the axis of the cylindrical bracket; An impeller cover fixedly connected to the end of the cylindrical bracket and covering the blade; A sintered ferrite magnetic ring disposed on the mounting position, defining the axial length of the sintered ferrite magnetic ring as L1, the bearing and the sintered ferrite magnetic ring having an overlapping portion in their axial directions, defining this overlapping portion as L2; the distance between the bearing and the blade is L3; further, the relationship among L1, L2, and L3 satisfies L1 / 5 ≤ L2 ≤ L1 / 4, and L2 ≤ 3.0 mm; A rotor chamber is formed inside the pump housing, the pump cover body and the pump housing are joined and fixed to each other, so that an impeller chamber is formed inside the pump cover body; the shaft core is axially disposed along the rotor chamber and the impeller chamber and is fixed in the rotor chamber and the impeller chamber; The rotor assembly is supported by the shaft core in the space enclosed by the pump cover body and the pump housing, so that the sintered ferrite magnetic ring is located in the rotor chamber, and the blade and the impeller cover are located in the impeller chamber; the stator assembly is disposed in the pump housing and disposed around the rotor chamber, so that the stator assembly can magnetically couple and drive the rotor assembly to rotate; When the rotor assembly rotates, at least a part of it contacts the thrust gasket; The drive circuit board is accommodated and fixed on one side of the pump housing relative to the pump cover, and the drive circuit board is electrically connected to the stator assembly, the end cover is fixed at one end of the pump housing relative to the pump cover, and the pump housing is sealed by the end cover, thereby sealing the stator assembly and the drive circuit board; The drive circuit board is fixed in the pump housing by at least one metal fixing member, and the metal fixing member is electrically connected to the negative electrode and / or the ground electrode of the drive circuit board through the printed circuit on the drive circuit board, so that the metal fixing member is grounded; A grounding post is integrally provided on the end cover; After the electronic water pump is assembled, the metal fixing member fixes the drive circuit board in the pump housing, and the grounding post on the end cover contacts the metal fixing member on the drive circuit board to complete the grounding of the end cover.

2. The electric water pump according to claim 1, wherein: The thrust washer mounting seat includes a coaxially arranged inner ring portion and an outer ring portion, and the inner ring portion and the outer ring portion are connected by connecting beams; The space enclosed by the outer wall of the inner ring portion, the inner wall of the outer ring portion, and two adjacent connecting beams is the snap mounting groove; At least the main circular ring portion of the thrust washer is fixedly attached to the end face of the inner ring portion.

3. The electric water pump according to claim 2, wherein: The snap portion of the thrust washer includes a first snap strip and a second snap strip; One end of the first snap strip is connected to the main circular ring portion, and the other end of the first snap strip is connected to the second snap strip; The first snap strip extends axially away from the main circular ring portion starting from the main circular ring portion, and the second snap strip folds back from the position where it is connected to the first snap strip and extends towards the main circular ring portion; The axial height of the first snap strip of the thrust washer is H1, and the axial height of the second snap strip of the thrust washer is H2, then: H2 - H1 > 0.5 mm.

4. The electric water pump according to claim 3, wherein: The angle between the first snap strip of the snap portion and the main circular ring portion is α, then: 70° ≤ α ≤ 105°; The minimum radial distance between the center point of the first snap strip and the main circular ring portion is R, the maximum radial distance between the end of the second snap strip and the center point of the main circular ring portion is B, the inner diameter of the snap mounting groove is D1, and the outer diameter of the snap mounting groove is D2, then: When 90° ≤ α ≤ 105°, there is At this time, the end of the second snap strip contacts the inner wall of the outer ring portion, and after deformation, the end of the second snap strip applies a rebound force to the inner wall of the outer ring portion; When 75° ≤ α ≤ 90°, there is At this time, the end of the second snap strip contacts the inner wall of the outer ring portion, and after deformation, the end of the second snap strip exerts a rebound force on the inner wall of the outer ring portion. At the same time, the first snap strip also tightly holds the outer wall of the inner ring portion.

5. The electric water pump according to claim 1, characterized in that: The metal fixing member is a screw for fixing the drive circuit board in the structure of the electronic water pump; The drive circuit board is provided with a printed circuit electrically connected to the negative pole and / or the grounding pole of the drive circuit board at the screw hole of the screw; After the electronic water pump is assembled, the screw contacts the printed circuit electrically connected to the negative pole and / or the grounding pole of the drive circuit board, and the grounding post on the end cover contacts the screw head of the screw.

6. The electric water pump according to claim 5, characterized in that: After the electronic water pump is assembled, the grounding post on the end cover applies an axial pressure to the screw head of the screw.

7. The electric water pump according to claim 6, characterized in that: The grounding post of the end cover is a frustum-shaped structure; The end diameter of the grounding post is D1, and the root diameter of the grounding post is D2, then: D1 < D2; After the electronic water pump is assembled, the end of the grounding post and the screw head groove of the screw are in interference fit in the radial direction.

8. The electric water pump according to claim 6, characterized in that: The grounding post of the end cover is a conical structure; The end diameter of the grounding post is D3, and D3 < 1.5 mm; After the electronic water pump is assembled, the end of the grounding post and the bottom of the screw head groove of the screw are in interference fit in the axial direction.

9. The electric water pump according to claim 1, wherein: The number of magnetic poles of the sintered ferrite magnetic ring is N, and both side surfaces of the sintered ferrite magnetic ring are provided with reinforcing holes adapted to the number of magnetic poles; the cylindrical bracket is provided with reinforcing columns corresponding to each of the reinforcing holes one by one.

10. The electric water pump according to claim 9, wherein: Define the depth of the reinforcement hole as H. The depth H of the reinforcement hole satisfies 0.2 mm ≤ H and H ≤ L1 / L3, where L1 is the axial length of the sintered ferrite magnetic ring and L3 is the distance between the rotating shaft and the blade.

11. An assembly method of an electronic water pump for assembling the electronic water pump according to any one of claims 1-10, characterized in that, Comprising: Machining the end cover: integrally machining the grounding post on the end cover; Assembling the pump cover: Align each buckle part of the formed thrust washer with the buckle installation slots of the thrust washer mounting seat of the pump cover body. Press the main circular ring part of the thrust washer to make each buckle part enter the buckle installation slots correspondingly until the main circular ring part of the thrust washer is placed against the end face of the thrust washer mounting seat; Assembling the rotor assembly: By means of in-mold injection molding, form the cylindrical bracket with blades on the bearing and the sintered ferrite magnetic ring, so that the bearing and the sintered ferrite magnetic ring have staggered parts in their axial directions, and fix the impeller cover at the end of the cylindrical bracket by ultrasonic welding; Overall assembly: Weld the phase pole pins of the stator assembly on the drive circuit board, and install the stator assembly and the drive circuit board together into the pump housing, so that the stator assembly is arranged around the rotor chamber. The drive circuit board is fixed in the pump housing by at least one metal fixing piece, and the metal fixing piece is electrically connected to the negative pole and / or the grounding pole of the drive circuit board through the printed circuit on the drive circuit board, so that the metal fixing piece is grounded. Fix the end cover at one end of the pump housing, seal the pump housing through the end cover, thereby sealing the stator assembly and the drive circuit board, and make the grounding post on the end cover contact the metal fixing piece on the drive circuit board to complete the grounding of the end cover; Fix one end of the shaft core in the rotor chamber, sleeve the bearing of the rotor assembly on the shaft core, and fix the pump cover body at the other end of the pump housing to cover the rotor assembly, so that at least a part of the rotor assembly contacts the thrust washer when rotating, and fix the other end of the shaft core on the pump cover body.

12. A new energy vehicle, characterized in that, Apply the electronic water pump according to any one of claims 1-10.

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