An electric water pump

Abstract

This invention discloses an electric water pump, comprising a housing, a pump shaft, a brushless motor, an impeller, and an electronic control board. The housing has an inlet, an outlet, an impeller cavity, a rotor cavity, and an electronic control cavity. The cavity wall between the electronic control cavity and the rotor cavity forms a heat-conducting wall with a minimum thickness of 0.5 mm. The first end of the pump shaft is located in the impeller cavity, and the second end is located in the rotor cavity and suspended above the heat-conducting wall. The electronic control board is installed inside the electronic control cavity and electrically connected to the stator to control the stator. The electronic control board is in contact with the heat-conducting wall. The electronic control board of this application has high heat dissipation efficiency.

Description

Technical Field

[0001] This invention relates to the field of water pumps, and more specifically to an electric water pump. Background Technology

[0002] In existing technology, centrifugal electric water pumps utilizing permanent magnet brushless motors are widely used in the automotive industry's cooling water circulation systems. These electric water pumps generally include a housing, pump shaft, brushless motor, electronic control board, and impeller. The housing is typically composed of an upper housing, a middle housing, and a lower housing fixedly connected together. The upper housing has an impeller cavity, an inlet, and an outlet; the inlet is axially connected to the impeller cavity, and the outlet is tangentially connected to the impeller cavity. The middle housing has a rotor cavity, and the upper and middle housings are watertightly connected to ensure axial communication between the impeller cavity and the rotor cavity. The middle and lower housings are fixedly connected and enclose an electronic control cavity. The impeller is placed within the impeller cavity, the rotor of the brushless motor is placed within the rotor cavity, and the stator of the brushless motor (including the stator section and winding section) is arranged around the rotor cavity and fixedly connected to the housing. The electronic control board, used to control the stator, is placed within the electronic control cavity. The pump shaft, rotor, and impeller are integrally fixedly connected. The pump shaft is supported by a bearing fixed to a support plate at the position between the rotor and the impeller. The support plate is fixedly connected to the stator. The lower end of the pump shaft is supported by a bearing fixed to the lower housing. The pump shaft, rotor, and impeller, which are fixed to each other, are driven by a brushless motor to pump water from the inlet through the impeller to the outlet. However, in the above-mentioned prior art, the heat dissipation efficiency of the electronic control board is poor. Summary of the Invention

[0003] The purpose of this invention is to overcome the above-mentioned defects or problems in the prior art and to provide an electric water pump with a high heat dissipation efficiency of its control board.

[0004] To achieve the above objectives, the present invention and its preferred embodiments employ the following technical solutions, but the embodiments are not limited to the following solutions:

[0005] The first technical solution and its related embodiments provide an electric water pump, including a housing with an inlet, an outlet, an impeller cavity, a rotor cavity, and an electrical control cavity; the inlet and outlet are connected to the impeller cavity, and the rotor cavity is axially connected to the impeller cavity; the electrical control cavity is adjacent to the rotor cavity and axially away from the impeller cavity; the cavity wall between the electrical control cavity and the rotor cavity forms a heat-conducting wall with a minimum thickness of 0.5 mm; a pump shaft, with its first end located in the impeller cavity and its second end located in the rotor cavity and suspended above the heat-conducting wall; a brushless motor, including a rotor and a stator, the rotor being located in the rotor cavity and rotatably connected to the pump shaft; the stator being fixedly connected to the housing and surrounding the rotor cavity; an impeller located in the impeller cavity and fixedly connected to the rotor; and an electrical control board installed in the electrical control cavity and electrically connected to the stator to control the stator, the electrical control board being attached to the heat-conducting wall.

[0006] Based on the first technical solution, a second technical solution is also provided. In the second technical solution and its related embodiments, the maximum thickness of the heat-conducting wall is 1.5 mm.

[0007] Based on the first technical solution, a third technical solution is also provided. In the third technical solution and its related embodiments, a connecting member is also included; the first end of the pump shaft is fixedly connected to the cavity wall of the impeller cavity through the connecting member.

[0008] Based on the third technical solution, a fourth technical solution is also provided. In the fourth technical solution and its related embodiments, the rotor includes a rotating sleeve and a rotor part that are fixedly connected to each other. The rotating sleeve is sleeved on the pump shaft and has a clearance fit with the pump shaft. The rotor part is sleeved outside the rotating sleeve. The connecting member is made of metal and is provided with a limiting wall suitable for direct contact with the rotating sleeve.

[0009] Based on the fourth technical solution, a fifth technical solution is also provided. In the fifth technical solution and its related embodiments, the connector is provided with a connector body and at least two connecting ribs. The connector body is sleeved on the first end of the pump shaft and is generally in the shape of a bullet facing the water inlet. One end of the connecting rib is fixed to the connector body, and the other end is fixed to the cavity wall of the impeller cavity. Each connecting rib is arranged circumferentially. The lower end face of the connector body forms the limiting wall.

[0010] Based on the fourth technical solution, a sixth technical solution is also provided. In the sixth technical solution and its related embodiments, a lower limiting member is also included; the rotor and the impeller are allowed to slide axially relative to the pump shaft, and the limiting wall limits the upward movement of the rotor and the impeller; the lower limiting member is fixed to the pump shaft and is used to limit the downward movement of the rotor and the impeller.

[0011] Based on any one of the fourth to sixth technical solutions, a seventh technical solution is also provided. In the seventh technical solution and its related embodiments, the housing includes an upper housing, a middle housing and a lower housing. The upper housing is watertightly connected to the middle housing, and the lower housing is fixedly connected to the middle housing. The impeller cavity, the water inlet and the water outlet are formed in the upper housing, and the rotor cavity is formed in the middle housing. The middle housing and the lower housing enclose the electrical control cavity.

[0012] Based on the seventh technical solution, an eighth technical solution is also provided. In the eighth technical solution and its related embodiments, the upper shell is made of plastic material, and the connector and the upper shell insert are integrally injection molded.

[0013] Based on the seventh technical solution, a ninth technical solution is also provided. In the ninth technical solution and its related embodiments, the upper shell is made of metal material, and the connector is welded to the upper shell.

[0014] Based on the seventh technical solution, a tenth technical solution is also provided. In the tenth technical solution and its related embodiments, the pump shaft is provided with a water passage along its extension direction, a high-pressure zone is formed between the impeller and the cavity wall of the impeller cavity, and the high-pressure zone is connected to a low-pressure zone near the water inlet through the rotor cavity and the water passage; the side cavity wall of the rotor cavity forms a heat dissipation wall, and a water passage gap is formed between the heat dissipation wall and the rotor, and the water passage gap is used to connect the high-pressure zone and the water passage.

[0015] As can be seen from the above description of the present invention and its preferred embodiments, compared with the prior art, the technical solution of the present invention and its preferred embodiments have the following beneficial effects due to the adoption of the following technical means:

[0016] In the first technical solution, since the second end of the pump shaft is located in the rotor cavity and suspended above the heat-conducting wall, the vibration of the rotor and impeller is not easily transmitted to the heat-conducting wall through the pump shaft, and the heat-conducting wall is less prone to cracking. In the prior art, to avoid cracking of the heat-conducting wall, it is often made thicker, and a limiting structure that mates with the second end of the pump shaft is often protruding on the heat-conducting wall. Thus, after the control board and the heat-conducting plate are attached, due to the thickness of the heat-conducting wall, the heat of the control board cannot be well transferred to the side of the heat-conducting wall located in the rotor cavity. Furthermore, since the limiting structure protruding on the heat-conducting wall occupies the space in the rotor cavity and is often located in the center of the heat-conducting wall, the coolant in the rotor cavity can only flow around the limiting structure, thus hindering the cooling of the rotor cavity. The liquid can only carry away the heat from the part of the control board that is offset from the limiting structure. Therefore, the heat of the control board cannot be effectively carried away by the water cooling in the rotor cavity, and it mainly dissipates heat through natural cooling. The heat dissipation efficiency of the control board is low. In this technical solution, the heat-conducting wall is not easy to crack, the minimum thickness of the heat-conducting wall is 0.5mm, the heat transfer rate of the heat-conducting wall is faster, and there is no extra structure between the heat-conducting wall and the second end of the pump shaft. The coolant in the rotor cavity can flow through the entire surface of the heat-conducting wall located in the rotor cavity, so that the heat of the control board can be carried away by the liquid cooling in the rotor cavity more quickly. The heat dissipation efficiency of the control board is high. Therefore, this technical solution not only avoids the cracking of the heat-conducting wall, but also improves the heat dissipation efficiency of the control board.

[0017] In the second technical solution and its preferred embodiment, the thickness of the heat-conducting wall is between 0.5mm and 1.5mm, which further ensures the strength of the heat-conducting wall and the heat dissipation efficiency of the electronic control board.

[0018] In the third technical solution and its preferred embodiment, the first end of the pump shaft is fixed to the cavity wall of the impeller chamber via a connector. Therefore, when the impeller rotates, the pump shaft is fixed to the housing very close to the upper part of the rotor. Compared with the prior art where the pump shaft is fixed to the housing in the rotor cavity, the pump shaft deflection caused by the centroid offset of the rotor and impeller during the operation of the electric water pump is smaller, the pump shaft vibration amplitude caused by the deflection is smaller, and the noise during the operation of the electric water pump is lower than that of the prior art. In addition, the machining accuracy of the connector is easier to ensure than that of the upper housing, and the offset between the axis of the pump shaft and the central axis of the impeller chamber is smaller.

[0019] In the fourth technical solution and its preferred embodiment, the connector is made of metal and has a limiting wall suitable for direct contact with the rotating sleeve. Compared with the solution of setting a gasket between the connector and the rotating sleeve, it is more conducive to reducing assembly steps, eliminating the risk of missing, over-assembly, and misalignment, and the structure is simpler.

[0020] In the fifth technical solution and its preferred embodiment, the connecting body for fixed connection with the pump shaft is connected to the upper housing via connecting ribs. These ribs are distributed circumferentially, and the spacing between them allows water to flow smoothly from the inlet into the impeller. The circumferential distribution of the connecting ribs also ensures the positional accuracy of the connecting body within the impeller cavity, minimizing the offset between the axis of the pump shaft connected to the connecting body and the central axis of the impeller cavity, thus effectively improving the operating efficiency of the electric water pump. The connecting body is fitted onto the first end of the pump shaft and is generally bullet-shaped, facing the inlet. Its upper surface is roughly conical or dome-shaped. This shape helps reduce the flow resistance of water flowing from the inlet to the impeller, improving the operating efficiency of the electric water pump. Compared to a solution where the connecting body and the first end of the pump shaft are fitted together to form a bullet shape facing the inlet, there is no need to consider the matching of the two components during processing, resulting in lower processing precision requirements and lower overall cost.

[0021] In the sixth technical solution and its preferred embodiment, by allowing the rotor and impeller to slide axially relative to the pump shaft as a whole, the rotor and impeller are easier to assemble onto the pump shaft as a whole. The limiting wall restricts the upward movement of the rotor and impeller as a whole, allowing the connector to have more functions besides connecting the pump shaft, resulting in a simpler structure. Simultaneously, because the limiting wall restricts the upward movement of the rotor and impeller as a whole, the fixed position of the pump shaft and housing is closer to the upper part of the rotor, which is beneficial for suppressing the deflection of the pump shaft. The lower limiting member restricts the downward movement of the rotor and impeller, preventing the rotor and impeller from impacting the connector due to excessive upward travel during rotation, which is beneficial for reducing noise and increasing lifespan, while also solving the problem of the rotor, which moves freely along the pump shaft axis during assembly, being magnetically attracted away.

[0022] In the eighth technical solution and its preferred embodiment, the upper shell is made of plastic material, and the connector and the upper shell insert are injection molded as one piece, which reduces the cost and ensures the positional accuracy of the connector in the impeller cavity. This makes the deviation between the axis of the pump shaft connected to the connector and the central axis of the impeller cavity smaller, which is beneficial to improving the operating efficiency of the electric water pump.

[0023] In the ninth technical solution and its preferred embodiment, the upper shell is made of metal, and the connecting parts are welded to the upper shell. This not only ensures the positional accuracy of the connecting parts in the impeller cavity, but also the metal upper shell has higher strength, which is more conducive to avoiding the vibration of the impeller and rotor being transmitted to the upper shell through the pump shaft, thus preventing the upper shell from cracking.

[0024] In the tenth technical solution and its preferred embodiment, the pump shaft is provided with a water passage along its extension direction. The high-pressure zone is connected to the low-pressure zone through the rotor cavity via the water passage, which can establish an internal circulation cooling channel inside the electric water pump. This allows water to flow from the high-pressure zone to the low-pressure zone through the internal circulation cooling channel, forming an internal circulation cooling water flow, which is beneficial for heat dissipation of the stator and the electronic control board. It should be understood that although the internal circulation cooling water flow may reduce the operating efficiency of the electric water pump, effective heat dissipation can improve the service life of the electric water pump. A water passage gap is formed between the heat dissipation wall and the rotor. The internal circulation cooling water flows through the water passage gap, making it easier to carry away the heat generated by the stator during the operation of the electric water pump, further improving the heat dissipation efficiency of the electric water pump. Attached Figure Description

[0025] To more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings used in the following description of the embodiments are briefly introduced. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0026] Figure 1 This is a top view of the electric water pump according to an embodiment of this application;

[0027] Figure 2 for Figure 1 Sectional view along the AA direction;

[0028] Figure 3 This is an exploded perspective view of the electric water pump according to an embodiment of this application.

[0029] Explanation of key figure labels:

[0030] Housing 10; Upper housing 11; Bolt hole 111; Middle housing 12; Through hole 121; Annular groove 122; Lower housing 13; Insertion part 131; Abutment wall 132; Heat dissipation wall 14; Heat conduction wall 15; Impeller cavity 01; Rotor cavity 02; Electrical control cavity 03; Inlet 04; Outlet 05; Connector 20; Connector body 21; Limiting wall 211; Through hole 212; Connecting rib 22; Embedded part 221; Pump shaft 30; Water passage 31; Impeller 40; Rotor 50; Rotor part 51; Rotating sleeve 52; Stator 60; Electrical control board 70; Lower limit part 80. Detailed Implementation

[0031] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are preferred embodiments of the present invention and should not be considered as excluding other embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are within the scope of protection of the present invention.

[0032] Unless otherwise expressly defined, the use of terms such as "first," "second," or "third" in the claims, description, and accompanying drawings of this invention is for distinguishing different objects and not for describing a specific order.

[0033] Unless otherwise expressly defined, in the claims, description, and accompanying drawings of this invention, the use of directional terms such as "center," "lateral," "longitudinal," "horizontal," "vertical," "top," "bottom," "inner," "outer," "upper," "lower," "front," "rear," "left," "right," "clockwise," and "counterclockwise" to indicate orientation or positional relationships is based on the orientation and positional relationships shown in the accompanying drawings and is only for the convenience of describing the invention and simplifying the description, and is not intended to 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 limiting the specific scope of protection of this invention.

[0034] Unless otherwise expressly defined, the terms "fixed connection" or "fixed connection" used in the claims, description and drawings of this invention should be interpreted broadly to refer to any connection in which there is no displacement or relative rotation relationship between the two parties, including non-removable fixed connection, detachable fixed connection, integral connection and fixed connection by other means or components.

[0035] In the claims, description and accompanying drawings of this invention, the terms "comprising," "having," and variations thereof are used to mean "including but not limited to."

[0036] In the claims and description, unless otherwise specified, the term "have" means that a technical feature that follows is part of a technical feature that precedes it.

[0037] Unless otherwise specified in the claims and description, the term "stator" includes not only the stator as understood by a person skilled in the art, but also the windings. That is, the stator includes a stator section and a winding section.

[0038] Unless otherwise specified in the claims and description, the term "watertight" refers to a liquid seal, which is commonly known to those skilled in the art to be achieved by conventional means such as sealing rings or sealing cups.

[0039] Unless otherwise specified in the claims and description, the term "insert injection molding" refers to a process in which two parts are tightly joined together and cannot be disassembled after injection molding by inserting components during the injection process.

[0040] Unless otherwise specified in the claims and description, the term "attached" means that the two are bonded together either directly or indirectly (e.g., through a thermally conductive material).

[0041] See Figure 1-3 , Figure 1-3 An electric water pump is shown, which includes a housing 10, a connector 20, a pump shaft 30, an impeller 40, a brushless motor, an electronic control board 70, and a lower limit member 80.

[0042] like Figure 2 As shown, the housing 10 includes an upper housing 11, a middle housing 12, and a lower housing 13. The upper housing 11 has an impeller cavity 01, an inlet 04, and an outlet 05. The impeller cavity 01 opens downwards, the inlet 04 axially connects to the top of the impeller cavity 01, and the outlet 05 tangentially connects to the impeller cavity 01. The middle housing 12 has a rotor cavity 02. The rotor cavity 02 opens upwards and has side walls, which form a heat dissipation wall 14. The upper housing 11 and the middle housing 12 are watertightly connected by a sealing ring and bolts. After the upper housing 11 and the middle housing 12 are fixedly connected, the impeller cavity 01 axially connects to the rotor cavity 02. The lower housing 13 is friction-welded to the middle housing 12. After the lower housing 13 and the middle housing 12 are fixedly connected, they enclose an electrical control cavity 03. The electrical control cavity 03 is adjacent to the rotor cavity 02 and axially away from the impeller cavity 01. A heat-conducting wall 15 is formed between the rotor cavity 02 and the electrical control cavity 03. The minimum thickness of the heat-conducting wall 15 is 0.5 mm, and in practical applications, the maximum thickness of the heat-conducting wall 15 is 1.5 mm. In this embodiment, the thickness of the heat-conducting wall 15 is 0.9 mm. Therefore, the housing 10 is provided with an inlet 04, an outlet 05, an impeller cavity 01, a rotor cavity 02, and an electrical control cavity 03.

[0043] like Figure 2-3As shown, the connector 20 has a connector body 21 and at least two connecting ribs 22. In this embodiment, there are four connecting ribs 22. The connector body 21 is used to fix to the pump shaft 30. The connector body 21 is a cylindrical shape with an opening facing downwards, and the bottom of the cylinder has a through hole 212. One end of each connecting rib 22 is fixed to the outer edge of the connector body 21, and the other end is fixed to the upper housing 11 near the water inlet 04, that is, the cavity wall of the impeller cavity 01. Each connecting rib 22 is arranged circumferentially. In this embodiment, the end of each connecting rib 22 away from the connector body 21 has a horizontally extending embedding part 221. In this embodiment, the connector 20 is made of metal and has a limiting wall 211 that directly abuts against the rotating sleeve 52 described below. The limiting wall 211 is formed on the lower end face of the connector 21. In one embodiment, the upper shell 11 is made of plastic. The connector 20 and the upper shell 11 are injection molded by insert molding. When the upper shell 11 is injection molded, the connector 20 inserts the insert 221 into the mold, so that the upper shell 11 and the connector 20 insert are integrally molded. In another embodiment, the upper shell 11 is made of metal, and a groove is formed on the upper shell 11 corresponding to each insert 221. The insert 221 is inserted into the groove and welded to the upper shell 11, thereby welding the connector 20 to the upper shell 11.

[0044] like Figure 2 As shown, the first end of the pump shaft 30 is located inside the impeller cavity 01 and faces the inlet 04 axially. The second end of the pump shaft 30 is located in the rotor cavity 02 and is suspended above the heat-conducting wall 15. In this embodiment, the pump shaft 30 is inserted into the cylinder formed by the connecting body 21 and abuts against the bottom of the cylinder. The pump shaft 30 can be fixed to the connecting body 21 by interference fit, or by other methods such as bonding, screwing, or embedding, which are well known to those skilled in the art. Therefore, in this embodiment, the pump shaft 30 is fixed relative to the housing 10. The pump shaft 30 has a water passage 31 that runs through the entire pump shaft 30 along its extension direction. The water passage 31 is correspondingly connected to the through hole 212. Therefore, the first end of the pump shaft 30 is fixed to the cavity wall of the impeller cavity 01 through the connecting member 20. In this embodiment, the first end of the pump shaft 30 is fixed to the connecting body 21, and the fixed position is located inside the impeller cavity 01. In other embodiments, the connecting body 21 can also be fixed to the other parts of the pump shaft 30 located inside the impeller cavity 01, except for the first end. In this embodiment, the connector 21 is sleeved on the first end of the pump shaft 30 and is generally bullet-shaped facing the inlet 04. Its upper surface is roughly conical or dome-shaped. This shape helps to reduce the flow resistance of water flowing from the inlet 04 to the impeller 40. In this embodiment, the pump shaft 30 can be made of plastic or metal.

[0045] like Figure 2As shown, the impeller 40 rotates relative to the pump shaft 30 within the impeller cavity 01 about the rotation axis defined by the pump shaft 30. The electric water pump pressurizes the water or liquid flow input from the inlet 04 and outputs it to the outlet 05 through the rotation of the impeller 40. In this embodiment, when the impeller 40 rotates in the impeller cavity 01, a high-pressure zone is formed between the impeller 40 and the cavity wall of the impeller cavity 01. Specifically, there is a gap between the outer edge of the impeller 40 and the side cavity wall of the impeller cavity 01, and this gap forms the high-pressure zone. Correspondingly, when the impeller 40 rotates in the impeller cavity 01, a low-pressure zone is formed in the area near the inlet 04. When the electric water pump is used to establish a circulating water flow, the rotation of the impeller 40 causes the pressure at the outlet 05 to be higher than the pressure at the inlet 04, causing the circulating water pump to return the water from the outlet 05 to the inlet 04.

[0046] like Figure 2 As shown, the brushless motor includes a stator 60 and a rotor 50. The stator 60 includes a stator section and a winding section. The stator 60 is fixedly connected to the middle housing 12 and surrounds the rotor cavity 02. The middle housing 12 also surrounds the stator 60. The stator 60 is watertight from the rotor cavity 02. The rotor 50 is located in the rotor cavity 02 and is rotatably connected to the pump shaft 30. The rotor 50 is sleeved on the pump shaft 30. In this embodiment, the rotor 50 includes a rotor section 51 and a rotating sleeve 52 fixedly connected to each other. The rotor section 51 and the stator 60 together constitute the brushless motor. The rotor section 51 is generally made of permanent magnet. The rotating sleeve 52 is sleeved on the pump shaft 30 and has a clearance fit with the pump shaft 30. The rotor section 51 is sleeved outside the rotating sleeve 52. The rotating sleeve 52 is located between the pump shaft 30 and the rotor section 51. In this embodiment, the rotating sleeve 52 is made of stainless steel.

[0047] like Figure 2 As shown, a water passage gap is formed between the rotor 50 and the heat dissipation wall 14, which connects the high-pressure area and the water passage 31. In this embodiment, the rotor 50 is fixedly connected to the impeller 40 so that the brushless motor can drive the impeller 40 to rotate around the pump shaft 30 within the impeller cavity 01. In this embodiment, the entire assembly formed by the rotor 50 and the impeller 40 is allowed to slide axially relative to the pump shaft 30, and is also allowed to rotate around the rotation axis relative to the pump shaft 30. In this embodiment, the connecting member 20 is located above the rotating sleeve 52, and the limiting wall 211 is used to limit the upward movement of the entire assembly formed by the rotor 50 and the impeller 40. Specifically, when the impeller 40 rotates, the impeller 40 will drive the rotor 50 to move upward together until the rotating sleeve 52 directly or indirectly abuts against the limiting wall 211 of the connecting member 20.

[0048] like Figure 2As shown, the electronic control board 70 is installed inside the electronic control cavity 03 and electrically connected to the stator 60 to control the stator 60, enabling the brushless motor to start, stop, and adjust its speed. In this embodiment, the electronic control board 70 is attached to the heat-conducting wall 15 via thermally conductive silicone. As is well known to those skilled in the art, the electronic control board 70 is also connected to external terminals via leads penetrating the lower housing 13 to obtain power and control signals from the outside.

[0049] like Figure 2 As shown, the lower limit member 80 is a snap ring, which is snapped onto the pump shaft 30 to fix it to the pump shaft 30. The lower limit member 80 is used to limit the downward movement of the whole formed by the rotor 50 and the impeller 40.

[0050] In this embodiment, the electric water pump will generate a main water flow and an internal circulating cooling water flow during operation. The main water flow is consistent with the prior art. As described above, during the rotation of the impeller 40, a high-pressure zone is formed between the impeller 40 and the cavity wall of the impeller cavity 01. The high-pressure zone is connected to the low-pressure zone near the inlet 04 through the rotor cavity 02 and the water passage 31. The water flows from the high-pressure zone through the water passage gap, the rotor cavity 02, and the water passage 31 to the low-pressure zone and merges with the main water flow. The low-pressure zone is located near the inlet 04, thereby forming an internal circulating cooling water flow. However, the internal circulating cooling water flow exchanges liquid with the main water flow. As described above, since the stator 60 is surrounded outside the rotor cavity 02, and the stator 60 is generally adjacent to or against the heat dissipation wall 14, the water flow passing through the water passage gap can carry away the heat generated by the stator 60 during the operation of the electric water pump. As described above, the heat generated by the electronic control board 70 during operation can be transferred to the heat-conducting wall 15, and the heat can be carried away by the water flow that is about to enter the second end of the pump shaft 30.

[0051] In general, during the assembly of an electric water pump, the stator 60 and the middle housing 12 are integrally molded using insert injection molding. The rotor 50 is placed inside the middle housing 12, and then the upper housing 11 is watertightly fixed to the middle housing 12. However, during the assembly of the control board 70, it is inserted from the opening on the side of the middle housing 12 away from the upper housing 11, and the lower housing 13 is then watertightly fixed to the middle housing 12. This means that the orientation of the housing 10 needs to be adjusted during assembly, causing inconvenience to on-site personnel. In this embodiment, to improve this problem, such as... Figure 2-3As shown, bolt holes 111 with openings facing the lower housing 13 are provided on the upper housing 11 for bolt fixing, and through holes 121 corresponding to the bolt holes 111 are provided on the middle housing 12. Therefore, during installation, the insertion direction of the control board 70 is consistent with the insertion direction of the bolts, which facilitates installation. In this embodiment, for ease of installation, an annular groove 122 is provided on the opening side of the middle housing 12 near the lower housing 13. The lower housing 13 is provided with an insertion part 131 that can be inserted into the annular groove 122 and an abutment wall 132 that abuts against the end of the groove wall of the annular groove 122. The insertion part 131 and the annular groove 122 can be welded together by friction welding. Compared with welding using sealing rings and screws, this not only reduces the number of parts but also reduces the outer diameter of the lower housing 13. Compared with laser welding, friction welding does not require the lower housing 13 to be transparent and does not produce spatter. Compared with ultrasonic welding, friction welding does not require high-frequency vibration and is less destructive to the product.

[0052] In this embodiment, since the second end of the pump shaft 30 is located in the rotor cavity 02 and suspended above the heat-conducting wall 15, the rotation of the rotor 50 and impeller 40 is not easily transmitted to the heat-conducting wall 15 through the pump shaft 30, and the heat-conducting wall 15 is not prone to cracking. In the prior art, in order to avoid cracking of the heat-conducting wall 15, the heat-conducting wall 15 is often made thicker, and a limiting structure that mates with the second end of the pump shaft 30 is often protruding on the heat-conducting wall 15. Thus, after the control board 70 is attached to the heat-conducting plate, due to the thickness of the heat-conducting wall 15, the heat of the control board 70 cannot be well transferred to the side of the heat-conducting wall 15 located in the rotor cavity 02. Furthermore, since the limiting structure protruding on the heat-conducting wall 15 occupies the space in the rotor cavity 02 and is often located in the center of the heat-conducting wall 15, the coolant in the rotor cavity 02 can only flow around the limiting structure. The coolant in the first part of the pump shaft 30 can only remove heat from the part of the control board 70 that is offset from the limiting structure. Therefore, the heat of the control board 70 cannot be effectively removed by the water cooling in the rotor cavity 02 and is mainly dissipated through natural cooling. The heat dissipation efficiency of the control board 70 is low. In this technical solution, the heat-conducting wall 15 is not easy to crack, the minimum thickness of the heat-conducting wall 15 is 0.5mm, the heat transfer rate of the heat-conducting wall 15 is faster, and there is no extra structure between the heat-conducting wall 15 and the second end of the pump shaft 30. The coolant in the rotor cavity 02 can flow through the entire surface of the heat-conducting wall 15 located in the rotor cavity 02, so that the heat of the control board 70 can be removed by the liquid cooling in the rotor cavity 02 more quickly. The heat dissipation efficiency of the control board 70 is high. Therefore, this technical solution not only avoids the cracking of the heat-conducting wall 15, but also improves the heat dissipation efficiency of the control board 70.

[0053] In this embodiment, the thickness of the heat-conducting wall 15 is between 0.5mm and 1.5mm, which further ensures the strength of the heat-conducting wall 15 and the heat dissipation efficiency of the electronic control board 70.

[0054] In this embodiment, the first end of the pump shaft 30 is fixed to the cavity wall of the impeller cavity 01 via the connector 20. Therefore, when the impeller 40 rotates, the pump shaft 30 is fixed to the housing 10 very close to the upper part of the rotor 50. Compared with the prior art where the pump shaft 30 is fixed to the housing 10 in the rotor cavity 02, the deflection of the pump shaft 30 caused by the centroid offset of the rotor 50 and impeller 40 during the operation of the electric water pump is smaller, the vibration amplitude of the pump shaft 30 caused by the deflection of the pump shaft 30 is smaller, and the noise during the operation of the electric water pump is reduced compared with the prior art. In addition, the machining accuracy of the connector 20 is easier to ensure than that of the upper housing 11, and the offset between the axis of the pump shaft 30 and the central axis of the impeller cavity 01 is smaller.

[0055] In this embodiment, the connector 20 is made of metal and has a limiting wall 211 that is suitable for direct contact with the rotating sleeve 52. Compared with the solution of setting a gasket between the connector 20 and the rotating sleeve 52, it is more conducive to reducing assembly steps, eliminating the risk of missing, over-assembly, and misalignment, and the structure is simpler.

[0056] In this embodiment, the connecting body 21, which is fixed to the pump shaft 30, is connected to the upper housing 11 via connecting ribs 22. The connecting ribs 22 are distributed circumferentially, and the spacing between them allows water to flow smoothly from the inlet 04 into the impeller 40. The circumferential distribution of the connecting ribs 22 also ensures the positional accuracy of the connecting body 21 within the impeller cavity 01, minimizing the offset between the axis of the pump shaft 30 connected to the connecting body 21 and the central axis of the impeller cavity 01, thus effectively improving the operating efficiency of the electric water pump. The connecting body 21 is fitted onto the first end of the pump shaft 30 and is generally bullet-shaped, facing the inlet 04. Its upper surface is roughly conical or dome-shaped. This shape helps reduce the flow resistance of water flowing from the inlet 04 to the impeller 40, improving the operating efficiency of the electric water pump. Compared to a scheme where the connecting body 21 and the first end of the pump shaft 30 are fitted together to form a bullet shape facing the inlet 04, there is no need to consider the matching of the two components during processing, resulting in lower processing precision requirements and lower overall cost.

[0057] In this embodiment, by allowing the rotor 50 and impeller 40 to slide axially relative to the pump shaft 30 as a whole, the rotor 50 and impeller 40 are more easily assembled onto the pump shaft 30. The limiting wall 211 limits the upward movement of the rotor 50 and impeller 40 as a whole, allowing the connector 20 to have more functions besides connecting the pump shaft 30, resulting in a simpler structure. Simultaneously, because the limiting wall 211 limits the upward movement of the rotor 50 and impeller 40 as a whole, the fixed position of the pump shaft 30 and the housing 10 is closer to the upper part of the rotor 50, which is beneficial for suppressing the deflection of the pump shaft 30. The lower limiting member 80 limits the downward movement of the rotor 50 and impeller 40, preventing the rotor 50 and impeller 40 from impacting the connector 20 due to excessive upward travel during rotation. This is beneficial for reducing noise and increasing lifespan, and also solves the problem of the rotor 50, which moves freely along the pump shaft 30 during assembly, being magnetically attracted away.

[0058] In this embodiment, the upper housing 11 is made of plastic, and the connector 20 is integrally injection molded with the upper housing 11 insert. This reduces cost and better ensures the positional accuracy of the connector 20 in the impeller cavity 01, resulting in a smaller deviation between the axis of the pump shaft 30 connected to the connector 21 and the central axis of the impeller cavity 01, which is beneficial to improving the operating efficiency of the electric water pump. In other embodiments, the upper housing 11 is made of metal, and the connector 20 is welded to the upper housing 11. This not only ensures the positional accuracy of the connector 20 in the impeller cavity 01, but the metal upper housing 11 also has higher strength, which is more conducive to preventing the vibration of the impeller 40 and rotor 50 from being transmitted to the upper housing 11 through the pump shaft 30, thus avoiding cracking of the upper housing 11.

[0059] In this embodiment, the pump shaft 30 is provided with a water passage 31 along its extension direction. The high-pressure area is connected to the low-pressure area through the rotor cavity 02 and the water passage 31, which can establish an internal circulation cooling channel inside the electric water pump. Water flows from the high-pressure area to the low-pressure area through the internal circulation cooling channel to form an internal circulation cooling water flow, which is beneficial for the heat dissipation of the stator 60 and the electronic control board 70. It should be understood that although the internal circulation cooling water flow may reduce the operating efficiency of the electric water pump, effective heat dissipation can improve the service life of the electric water pump. A water passage gap is formed between the heat dissipation wall 14 and the rotor 50. The internal circulation cooling water flows through the water passage gap, making it easier to carry away the heat generated by the stator 60 during the operation of the electric water pump, further improving the heat dissipation efficiency of the electric water pump.

[0060] The foregoing description of the specifications and embodiments is intended to explain the scope of protection of this invention, but does not constitute a limitation on the scope of protection of this invention. Modifications, equivalent substitutions, or other improvements to the embodiments of this invention or a portion thereof that can be obtained by those skilled in the art through logical analysis, reasoning, or limited experimentation, based on the teachings of this invention or the foregoing embodiments, in conjunction with common knowledge, general technical knowledge, and / or existing technology, should all be included within the scope of protection of this invention.

Claims

1. An electric water pump, characterized in that, include The housing (10) is provided with an inlet (04), an outlet (05), an impeller cavity (01), a rotor cavity (02), and an electrical control cavity (03); the inlet (04) and the outlet (05) are connected to the impeller cavity (01), and the rotor cavity (02) is axially connected to the impeller cavity (01); the electrical control cavity (03) is adjacent to the rotor cavity (02) and axially away from the impeller cavity (01); the cavity wall between the electrical control cavity (03) and the rotor cavity (02) forms a heat-conducting wall (15), and the minimum thickness of the heat-conducting wall (15) is 0.5 mm; A pump shaft (30) has its first end located in the impeller cavity (01) and its second end located in the rotor cavity (02) and suspended above the heat-conducting wall (15); a brushless motor includes a rotor (50) and a stator (60), wherein the rotor (50) is located in the rotor cavity (02) and is rotatably connected to the pump shaft (30); the stator (60) is fixed to the housing (10) and surrounds the rotor cavity (02); Impeller (40), which is located in impeller cavity (01) and fixedly connected to the rotor (50); and An electrical control board (70) is installed in the electrical control cavity (03) and electrically connected to the stator (60) to control the stator (60). The electrical control board (70) is attached to the heat-conducting wall (15).

2. The electric water pump as described in claim 1, characterized in that, The maximum thickness of the heat-conducting wall (15) is 1.5 mm.

3. The electric water pump as described in claim 1, characterized in that, It also includes a connector (20); the first end of the pump shaft (30) is fixed to the cavity wall of the impeller cavity (01) through the connector (20).

4. An electric water pump as described in claim 3, characterized in that, The rotor (50) includes a rotating sleeve (52) and a rotor part (51) fixedly connected to each other. The rotating sleeve (52) is sleeved on the pump shaft (30) and has a clearance fit with the pump shaft (30). The rotor part (51) is sleeved outside the rotating sleeve (52). The connecting member (20) is made of metal and has a limiting wall (211) suitable for direct contact with the rotating sleeve (52).

5. An electric water pump as described in claim 4, characterized in that, The connector (20) is provided with a connector (21) and at least two connecting ribs (22). The connector (21) is sleeved on the first end of the pump shaft (30) and is bullet-shaped facing the water inlet (04). One end of the connecting rib (22) is fixed to the connector (21), and the other end is fixed to the cavity wall of the impeller cavity (01). Each connecting rib (22) is arranged circumferentially. The lower end face of the connector (21) forms the limiting wall (211).

6. An electric water pump as described in claim 4, characterized in that, It also includes a lower limiting member (80); the rotor (50) and the impeller (40) are allowed to slide axially relative to the pump shaft (30), and the limiting wall (211) limits the upward movement of the rotor (50) and the impeller (40); the lower limiting member (80) is fixed to the pump shaft (30) and is used to limit the downward movement of the rotor (50) and the impeller (40).

7. An electric water pump as described in any one of claims 4-6, characterized in that, The housing (10) includes an upper housing (11), a middle housing (12) and a lower housing (13). The upper housing (11) is watertightly connected to the middle housing (12), and the lower housing (13) is fixedly connected to the middle housing (12). The impeller cavity (01), the inlet (04) and the outlet (05) are formed in the upper housing (11), and the rotor cavity (02) is formed in the middle housing (12). The middle housing (12) and the lower housing (13) together form the electrical control cavity (03).

8. An electric water pump as described in claim 7, characterized in that, The upper housing (11) is made of plastic, and the connector (20) and the upper housing (11) insert are integrally injection molded.

9. An electric water pump as described in claim 7, characterized in that, The upper housing (11) is made of metal, and the connector (20) is welded to the upper housing (11).

10. An electric water pump as described in claim 7, characterized in that, The pump shaft (30) is provided with a water passage (31) along its extension direction. A high-pressure zone is formed between the impeller (40) and the cavity wall of the impeller cavity (01). The high-pressure zone is connected to a low-pressure zone near the inlet (04) through the rotor cavity (02) and the water passage (31). A heat dissipation wall (14) is formed on the side cavity wall of the rotor cavity (02). A water passage gap is formed between the heat dissipation wall (14) and the rotor (50). The water passage gap is used to connect the high-pressure zone and the water passage (31).

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