An electric water pump

Abstract

The present application discloses an electric water pump, which includes a pump body, a pump shaft, a brushless motor, an impeller and a connecting part; the pump body is provided with a water inlet, a water outlet, an impeller cavity and a rotor cavity; the water inlet and the water outlet are connected to the impeller cavity, and the rotor cavity is axially connected to the impeller cavity; the first end of the pump shaft is located in the impeller cavity, and the second end is located in the rotor cavity; the brushless motor includes a rotor and a stator, the rotor is located in the rotor cavity and is rotatably connected to the pump shaft, and the stator is fixedly connected to the pump body and is surrounded outside the rotor cavity; the impeller is located in the impeller cavity and is fixedly connected to the rotor; the connecting part connects the cavity wall of the impeller cavity and the part of the pump shaft extending into the impeller cavity, so that the pump shaft is fixedly connected to the pump body. The above technical solution can effectively reduce the noise during the operation of the electric water pump compared with the prior art. The present application also uses a hollow pump shaft structure to form an internal circulation cooling water flow from the high-pressure area of ​​the impeller cavity to the low-pressure area near the first end of the hollow pump shaft, taking away the heat of the stator and the electric control board, and effectively extending the service life of the brushless motor.

Description

Technical Field

[0001] The present application relates to the field of water pumps, and in particular to an electric water pump, and in particular to an electric centrifugal water pump. Background Art

[0002] In the prior art, centrifugal electric water pumps using permanent magnet brushless motors have been widely used in cooling water circulation systems in the automotive industry. Such electric water pumps generally include a pump body, a pump shaft, a brushless motor, an electric control board and an impeller. The pump body is generally formed by the upper shell, the middle shell and the lower shell being fixedly connected; the upper shell is provided with an impeller cavity, a water inlet and a water outlet, the water inlet is axially connected to the impeller cavity, and the water outlet is tangentially connected to the impeller cavity; the middle shell is provided with a rotor cavity, and the upper shell and the middle shell are watertightly fixed to enable the impeller cavity and the rotor cavity to be axially connected. The middle shell and the lower shell are fixedly connected and enclosed to form an electric control cavity. The impeller is placed in the impeller cavity, the rotor of the brushless motor is placed in the rotor cavity, the stator of the brushless motor (including the stator part and the winding part) is arranged around the impeller cavity and fixedly connected to the pump body, and the electric control board is used to control the stator and is placed in the electric control cavity. The pump shaft, the rotor and the impeller are fixedly connected as a whole, and the pump shaft is supported by a bearing fixed to a support plate at a position between the rotor and the impeller, and 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 fixed to each other are driven by a brushless motor so that water flows from the water inlet through the impeller and out of the water outlet.

[0003] However, the above-mentioned prior art has the defects of complex structure, high parts and assembly cost, etc. Therefore, the prior art provides an improved electric water pump, which fixes the pump shaft to the middle shell or the lower shell, and the rotor and impeller fixed to each other are rotatably connected to the pump shaft, and at the same time, the end of the pump shaft close to the water inlet is in clearance with the limiter extending from the upper shell, and the limiter radially limits the end of the pump shaft close to the water inlet; therefore, in the improved electric water pump, the rotor and impeller fixed to each other only need to be in clearance with the pump shaft, the structure is relatively simple, and the assembly is relatively easy.

[0004] However, during the operation of the above-mentioned improved electric water pump, there is a problem of high noise. Utility Model Content

[0005] The purpose of the present application is to overcome the above-mentioned defects or problems existing in the background technology and to provide an electric water pump which can reduce the noise and vibration during the operation of the electric water pump compared with the prior art.

[0006] In order to achieve the above purpose, the following technical solutions are adopted:

[0007] The first technical scheme relates to an electric water pump, which includes a pump body, which is provided with a water inlet, a water outlet, an impeller cavity and a rotor cavity; the water inlet and the water outlet are connected to the impeller cavity, and the rotor cavity is axially connected to the impeller cavity; a pump shaft, a first end of which is located in the impeller cavity, and a second end of which is located in the rotor cavity; a brushless motor, which includes a rotor and a stator, the rotor is located in the rotor cavity and is rotationally connected to the pump shaft, the stator is fixed to the pump body and is surrounded by the rotor cavity; and an impeller, which is located in the impeller cavity and is fixed to the rotor; it also includes a connecting part, the connecting part connects the cavity wall of the impeller cavity and the part of the pump shaft extending into the impeller cavity, so that the pump shaft is fixed to the pump body.

[0008] The second technical solution is based on the first technical solution, wherein the rotor and the impeller are allowed to slide axially relative to the pump shaft, and the connecting portion limits the upward movement of the rotor and the impeller.

[0009] The third technical solution is based on the second technical solution, and further includes a gasket and a lower limit member; the gasket is arranged between the connecting portion and the rotor; the lower limit member is fixedly connected to the pump shaft and is used to limit the downward movement of the rotor and the impeller.

[0010] The fourth technical solution is based on the first technical solution, wherein the pump body is further provided with a limiting portion, the limiting portion is located in the rotor cavity and below the rotor, the limiting portion is clearance-matched with the pump shaft and radially limits the pump shaft.

[0011] The fifth technical solution is based on the first technical solution, wherein the connecting portion is provided with a connecting body and at least two connecting ribs, the connecting body is used to fix the pump shaft, one end of the connecting rib is fixed to the connecting body, and the other end is fixed to the cavity wall of the impeller cavity, and each connecting rib is arranged along the circumferential direction.

[0012] The sixth technical solution is based on the fifth technical solution, wherein the connector is fixedly connected to the first end of the pump shaft so that the whole formed by the two is in the shape of a bullet head facing the water inlet.

[0013] The seventh technical solution is based on the first technical solution, wherein the rotor includes a rotor part and a rotating sleeve, the rotor part and the stator constitute a brushless motor, and the rotating sleeve is loosely matched with the pump shaft and fixedly connected to the rotor part.

[0014] The eighth technical solution is based on any one of the first to seventh technical solutions, wherein the electric water pump also includes an electric control board; the pump body is also provided with an electric control chamber, which is adjacent to the rotor chamber and axially away from the impeller chamber; the electric control board is installed in the electric control chamber and is electrically connected to the stator to control the stator.

[0015] The ninth technical solution is based on the eighth technical solution, wherein the pump body includes an upper shell, a middle shell and a lower shell, the upper shell is watertightly fixed to the middle shell, the lower shell is fixed to the middle shell, the impeller chamber, the water inlet and the water outlet are formed in the upper shell, the rotor chamber is formed in the middle shell, and the middle shell and the lower shell are enclosed to form the electric control chamber.

[0016] The tenth technical solution is based on the ninth technical solution, wherein the connecting portion and the upper shell are integrally formed.

[0017] The eleventh technical solution is based on the tenth technical solution, wherein the material of the upper shell is plastic, the material of the connecting part is a material with higher strength than plastic, and the connecting part and the upper shell insert are integrally formed by injection molding.

[0018] The twelfth technical solution is based on the ninth technical solution, wherein the upper shell, the connecting part and the pump shaft are integrally formed.

[0019] The thirteenth technical solution is based on the eighth technical solution, wherein the pump shaft is provided with a water channel along its extension direction, and a high-pressure area is formed between the impeller and the cavity wall of the impeller cavity, and the high-pressure area is connected to the low-pressure area near the water inlet through the rotor cavity and the water channel.

[0020] The fourteenth technical solution is based on the thirteenth technical solution, wherein the side cavity wall of the rotor cavity forms a first heat dissipation wall, and a water gap is formed between the first heat dissipation wall and the rotor, and the water gap is used to connect the high-pressure area and the water channel.

[0021] The fifteenth technical solution is based on the thirteenth technical solution, wherein the cavity wall between the rotor cavity and the electric control cavity forms a second heat dissipation wall, the second end of the pump shaft is close to the second heat dissipation wall, and the electric control board is attached to the second heat dissipation wall.

[0022] Compared with the prior art, the above solution has the following beneficial effects:

[0023] In the first technical solution, the connecting part connects the cavity wall of the impeller cavity and the part of the pump shaft extending into the impeller cavity, so that the pump shaft is fixed to the pump body. Therefore, when the impeller rotates, the position where the pump shaft is fixed to the pump body is very close to the upper part of the rotor. Compared with the prior art that sets the position where the pump shaft is fixed to the pump body in the rotor cavity, the pump shaft flexural deformation caused by the centroid offset of the rotor and the impeller during the operation of the electric water pump is smaller, and the pump shaft vibration amplitude caused by the flexural deformation of the pump shaft is smaller, so the noise during the operation of the electric water pump is lower than that of the prior art. The following is a specific description: The applicant has found through continuous experiments, observations and analysis that the center of mass of the whole formed by the impeller and the rotor must deviate from the axis of rotation during the actual assembly process, and the impeller diameter is larger than the rotor, and the mass of the rotor is larger than the impeller. At the same time, the impeller is often not directly matched with the pump shaft, but is matched by the rotor and the pump shaft. Therefore, the equivalent center of mass of the whole formed by the impeller and the rotor during the rotation process is often located at the upper part of the rotor. In the prior art, the lower end of the pump shaft is fixedly connected to the middle housing, and the upper end of the pump shaft is only loosely matched with the stopper. Therefore, the deviation formed by the equivalent center of mass of the upper part of the rotor will drive the pump shaft to bend and deform and form vibrations, thereby generating noise. In addition, the pump shaft is prone to periodic collisions with the stopper during the rotation of the impeller, which will also generate noise. In the first technical solution, the pump shaft is fixedly connected to the pump body very close to the upper part of the rotor. Therefore, the deformation of the pump shaft caused by the radial force applied to the pump shaft by the deviation of the equivalent center of mass of the upper part of the rotor is very effectively weakened, the pump shaft is less prone to bend and deform, the periodic vibration amplitude is smaller, and the noise and vibration during the operation of the electric water pump are effectively reduced.

[0024] In the first technical solution, since the connecting portion is fixedly connected to the pump shaft and to the wall of the impeller cavity of the upper shell, the machining accuracy of the connecting portion relative to the upper shell is easier to ensure, and the offset between the rotation axis of the pump shaft and the central axis of the impeller cavity is smaller. In the prior art, the pump shaft is connected to the middle shell, and the middle shell often needs to be assembled with the upper shell through a nut. Therefore, the offset between the rotation axis of the pump shaft and the central axis of the impeller cavity is not easy to ensure, and the deviation after assembly is greater. The greater the offset between the rotation axis of the pump shaft and the central axis of the impeller cavity, the more difficult it is to evenly distribute the gap between the outer edge of the impeller and the wall of the impeller cavity, resulting in a decrease in the operating efficiency of the electric water pump, and even the occurrence of the impeller hitting the inner wall of the upper shell. The first technical solution effectively improves the above-mentioned defects, can improve the operating efficiency of the electric water pump, and avoid the impeller hitting the inner wall of the upper shell.

[0025] In the second technical solution, by allowing the rotor and the impeller to slide axially relative to the pump shaft, the rotor and the impeller as a whole are easier to assemble to the pump shaft. The connection part limits the upward movement of the rotor and the impeller as a whole, so that the connection part has more functions besides connecting the pump shaft, and the structure is simpler. At the same time, as mentioned above, since the connection part limits the upward movement of the rotor and the impeller as a whole, the fixed position of the pump shaft and the pump body is closer to the upper part of the rotor, which is beneficial to suppress the change of the flexural shape of the pump shaft.

[0026] In the third technical solution, the gasket is arranged between the connection part and the rotor, which can reduce the rotational friction between the rotor and the connection part and increase the life of the electric water pump. The lower limiter limits the downward movement of the rotor and the impeller, so that the rotor and the impeller will not hit the connection part due to the long upward stroke during the rotation process, which is beneficial to reducing noise and increasing the life. At the same time, it solves the problem that the rotor that moves freely along the axial direction of the pump shaft during the assembly process will be sucked away by the magnetic force.

[0027] In the fourth technical solution, the limiting portion is located below the rotor and limits the radial position of the pump shaft, which can further reduce the flexural deformation of the second end of the pump shaft and further reduce the noise generated by the vibration of the pump shaft.

[0028] In the fifth technical solution, the connector for fixing the pump shaft is connected to the upper housing through connecting ribs, and the connecting ribs are distributed along the circumferential direction. The intervals between the connecting ribs can allow water to flow smoothly from the water inlet into the impeller. The circumferential distribution of the connecting ribs can also ensure the position accuracy of the connector in the impeller cavity, so that the rotation axis of the pump shaft connected to the connector and the central axis of the impeller cavity are less offset, which can effectively improve the operating efficiency of the electric water pump.

[0029] In the sixth technical solution, the connector and the first end of the pump shaft form a bullet-shaped overall structure, and its upper surface is roughly conical or steamed bun-shaped. Such a shape is conducive to reducing the flow resistance of water flowing from the water inlet to the impeller and improving the operating efficiency of the electric water pump.

[0030] In the seventh technical solution, the rotor part is rotatably connected to the pump shaft through a rotating sleeve, which can reduce the rotational friction between the rotor and the pump shaft and increase the life of the electric water pump.

[0031] In the eighth technical solution, the electric control board is protected by the electric control cavity and is easy to be electrically connected to the stator, so that the electric water pump product has better integrity.

[0032] In the tenth technical solution, the connecting part and the upper shell are integrally formed, which can better ensure the position accuracy of the connecting part in the impeller cavity, so that the deviation between the rotation axis of the pump shaft connected to the connecting body and the central axis of the impeller cavity is smaller, which is beneficial to improving the operating efficiency of the electric water pump.

[0033] In the eleventh technical solution, the material of the connecting part and the upper shell is plastic, and the material of the pump shaft is a material with higher strength than plastic, including but not limited to metal. This not only makes the connecting part and the upper shell firmly connected, but also ensures the processing accuracy of the connecting part, so that the rotation axis of the pump shaft connected to the connecting part can deviate less from the central axis of the impeller chamber, which is beneficial to improving the operating efficiency of the electric water pump.

[0034] In the twelfth technical solution, the upper shell, the connecting part and the pump shaft are formed in one piece, which makes the processing simpler and improves the assembly efficiency.

[0035] In the thirteenth technical solution, a water channel is provided along the extension direction of the pump shaft, and the high-pressure area is connected to the low-pressure area through the rotor cavity and the water channel, so that an internal circulation cooling flow channel can be established inside the electric water pump, so that water flows from the high-pressure area through the internal circulation cooling flow channel to the low-pressure area to form an internal circulation cooling water flow, which is beneficial to the heat dissipation of the stator and the electronic control board. Although the internal circulation cooling water flow may reduce the operating efficiency of the electric water pump, effective heat dissipation can increase the service life of the electric water pump.

[0036] In the thirteenth technical solution, since the part of the pump shaft extending into the impeller cavity is fixedly connected to the connecting part, the vibration of the pump shaft, especially its second end, is smaller. If it is necessary to radially limit the lower part (for example, its second end), the strength of the limiting part does not need to be too high. Therefore, the radial wall thickness of the limiting part can be set to be thinner, which is beneficial to the heat dissipation of the electronic control board.

[0037] In the fourteenth technical solution, a water gap is formed between the first heat dissipation wall and the rotor. When the internal circulating cooling water flows through the water gap, the flow velocity is accelerated due to the Venturi effect, making it easier to take away the heat generated by the stator during the operation of the electric water pump.

[0038] In the fifteenth technical solution, the second end of the pump shaft is close to the second heat dissipation wall. Based on the Venturi effect, the internal circulation cooling water flow is forced to pass through the second heat dissipation wall quickly, and the electronic control board is close to the second heat dissipation wall, which makes it easier to take away the heat generated by the electronic control board during the operation of the electric water pump. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] In order to more clearly illustrate the technical solution of the embodiment, the following briefly introduces the drawings required for use:

[0040] Figure 1 is a top view of the electric water pump in the first embodiment;

[0041] Figure 2 for Figure 1 One of the AA section views;

[0042] Figure 3 for Figure 1 The second AA section view;

[0043] Figure 4Schematic diagram of the internal circulation cooling water flow of the electric water pump in Example 1;

[0044] Figure 5 It is a schematic diagram of the force on the pump shaft of the electric water pump in the first embodiment;

[0045] Figure 6 It is a schematic diagram of the structure of the electric water pump in the second embodiment;

[0046] Figure 7 It is a schematic diagram of the structure of the electric water pump in the third embodiment;

[0047] Figure 8 It is a schematic diagram of the structure of the electric water pump in the fourth embodiment.

[0048] Description of main reference numerals:

[0049] 1. Electric water pump; 2. Pump body; 3. Connecting part; 4. Pump shaft; 5. Impeller; 6. Brushless motor; 7. Electric control board; 8. Gasket; 9. Lower limiter; 10. Upper shell; 11. Middle shell; 12. Lower shell; 13. Impeller cavity; 14. Water inlet; 15. Water outlet; 16. Rotor cavity; 17. First heat dissipation wall; 18. Electric control cavity; 19. Second heat dissipation wall; 20. Connector; 21 , connecting rib; 22, first end; 23, second end; 24, water channel; 25, stator; 26, rotor; 27, stator part; 28, winding part; 29, rotor part; 30, rotating sleeve; 31, water gap; 32, high pressure area; 33, low pressure area; 34, insert part; 35, limit part; 36, water hole; f1: main water flow; f2: internal circulation cooling water flow; F, radial force on the pump shaft. DETAILED DESCRIPTION

[0050] In the claims and the description, unless otherwise defined, the terms "first", "second" or "third", etc. are intended to distinguish different objects rather than to describe a specific order.

[0051] In the claims and the specification, unless otherwise defined, terms such as "center", "lateral", "longitudinal", "horizontal", "vertical", "top", "bottom", "inside", "outside", "up", "down", "front", "back", "left", "right", "clockwise", "counterclockwise" and the like indicating directions or positional relationships are based on the directions and positional relationships shown in the drawings and are only for the convenience of simplifying the description and do not imply that the device or element referred to must have a specific direction or be constructed and operated in a specific direction.

[0052] In the claims and the specification, unless otherwise defined, the term "fixed connection" or "fixed connection" should be understood in a broad sense, that is, any connection method in which there is no displacement relationship and relative rotation relationship between the two parties, that is to say, including non-detachable fixed connection, detachable fixed connection, integral connection and fixed connection through other devices or elements.

[0053] In the claims and the description, unless otherwise defined, the terms "includes", "has" and their variations mean "including but not limited to".

[0054] In the claims and the specification, unless otherwise defined, the term "provided with" means that the technical feature located thereafter is a part of the technical feature located therefor.

[0055] In the claims and the specification, unless otherwise defined, the term "stator" includes not only a stator as understood by a person skilled in the art, but also a winding, that is, the stator includes a stator part and a winding part.

[0056] In the claims and the specification, unless otherwise defined, the term "watertight" refers to liquid sealing, and those skilled in the art are accustomed to knowing that liquid sealing can be achieved by conventional means such as sealing rings or sealing leather cups.

[0057] In the claims and description, unless otherwise defined, the term "insert molding" refers to a processing method in which a component is embedded during injection molding so that the two are tightly combined and cannot be disassembled after injection molding.

[0058] In the claims and the specification, unless otherwise defined, the term "abutting against" means that two things are closely attached or indirectly attached together (for example, through a heat conductive material).

[0059] In the claims and description, unless otherwise defined, the term "radial limitation" refers to limiting the movement in a direction perpendicular to the axis of rotation. Such limitation includes not only making it impossible to move, but also limiting the degree of movement.

[0060] The technical solutions in the embodiments will be described clearly and completely below in conjunction with the accompanying drawings.

[0061] Embodiment 1

[0062] See also Figures 1 to 5 , Figures 1 to 5 The electric water pump 1 in the first embodiment is shown.

[0063] like Figure 2 As shown, in this embodiment, the electric water pump 1 includes a pump body 2, a connecting portion 3, a pump shaft 4, an impeller 5, a brushless motor 6, an electric control board 7, a gasket 8 and a lower limit member 9.

[0064] like Figure 2As shown, the pump body 2 includes an upper shell 10 , a middle shell 11 and a lower shell 12 .

[0065] like Figure 3 As shown, the upper shell 10 is provided with an impeller chamber 13, a water inlet 14 and a water outlet 15. The impeller chamber 13 opens downward, the water inlet 14 is axially connected to the top of the impeller chamber 13, and the water outlet 15 is tangentially connected to the impeller chamber 13. The middle shell 11 is provided with a rotor chamber 16. The rotor chamber 16 opens upward and is provided with a side chamber wall. The side chamber wall of the rotor chamber 16 forms a first heat dissipation wall 17. The upper shell 10 and the middle shell 11 are watertightly fixed by a sealing ring and bolts. After the upper shell 10 and the middle shell 11 are fixed, the impeller chamber 13 is axially connected to the rotor chamber 16. The lower shell 12 and the middle shell 11 are fixed by bolts. After the lower shell 12 and the middle shell 11 are fixed, they are enclosed to form an electric control chamber 18. The electric control chamber 18 is adjacent to the rotor chamber 16 and is axially away from the impeller chamber 13. The rotor chamber 16 and the electric control chamber 18 are watertightly isolated by a second heat dissipation wall 19.

[0066] like Figure 2 As shown, the connection portion 3 is provided with a connection body 20 and at least two connection ribs 21. In this embodiment, there are four connection ribs 21. The connection body 20 is used to be fixedly connected to the pump shaft 4. One end of each connection rib 21 is fixedly connected to the outer edge of the connection body 20, and the other end is fixedly connected to the position of the upper shell 10 near the water inlet 14, that is, connected to the cavity wall of the impeller cavity 13. Each connection rib 21 is arranged along the circumferential direction.

[0067] like Figure 3 As shown, the first end 22 of the pump shaft 4 extends into the impeller cavity 13 and axially faces the water inlet 14, and the second end 23 of the pump shaft 4 extends into the rotor cavity 16 and is close to the second heat dissipation wall 19. In this embodiment, the pump shaft 4 is provided with a water passage 24 that runs through the entire pump shaft 4 along its extension direction. The first end 22 of the pump shaft 4 is interference-fitted with the connector 20, so that the pump shaft 4 is fixedly connected to the pump body 2, and the fixed position is located in the impeller cavity 13. In other embodiments, the connector 20 can also be fixedly connected to the other part of the pump shaft 4 located in the impeller cavity 13 except the first end 22. In this embodiment, after the first end 22 of the pump shaft 4 is connected to the connector 20, the whole formed by the two is in the shape of a bullet head, and its upper surface is roughly conical or steamed bun-shaped. Such a shape is conducive to reducing the flow resistance of the water flow from the water inlet 14 to the impeller 5.

[0068] In this embodiment, the materials of the connecting portion 3 and the upper shell 10 are both plastic, and the two are integrally injection molded. The material of the pump shaft 4 is metal (such as stainless steel), and the pump shaft 4 and the connecting body 20 can be fixedly connected not only by interference fit, but also by, for example, bonding, screwing, crimping or other methods commonly used by ordinary technicians in the field.

[0069] like Figure 3As shown, the impeller 5 rotates in the impeller chamber 13 relative to the pump shaft 4 around the rotation axis defined by the pump shaft 4. The electric water pump 1 increases the pressure of the water flow or liquid flow input from the water inlet 14 and outputs it to the water outlet 15 through the rotation of the impeller 5. In this embodiment, when the impeller 5 rotates in the impeller chamber 13, a high-pressure area 32 is formed between the impeller 5 and the cavity wall of the impeller chamber 13. Specifically, there is a gap between the outer edge of the impeller 5 and the side cavity wall of the impeller chamber 13, and the gap forms the high-pressure area 32. Correspondingly, when the impeller 5 rotates in the impeller chamber 13, a low-pressure area 33 is formed in the area near the water inlet 14. When the electric water pump 1 is used to establish a circulating water flow, the rotation of the impeller 5 makes the pressure of the water outlet 15 higher than the pressure of the water inlet 14, so that the circulating water is pumped out from the water outlet 15 and flows back to the water inlet 14.

[0070] like Figure 2 As shown, the brushless motor 6 includes a stator 25 and a rotor 26. The stator 25 includes a stator portion 27 and a winding portion 28. The stator 25 is fixedly connected to the middle housing 11 and is arranged outside the rotor cavity 16, and the middle housing 11 is also wrapped outside the stator 25. The stator 25 is watertightly isolated from the rotor cavity 16. The rotor 26 includes a rotor portion 29 and a rotating sleeve 30. Among them, the rotor portion 29 and the stator 25 together constitute the brushless motor 6, and the rotor portion 29 generally adopts a permanent magnet. The rotating sleeve 30 is sleeved on the pump shaft 4 and has a clearance fit with the pump shaft 4. The rotating sleeve 30 is fixedly connected to the rotor portion 29. The rotating sleeve 30 is located between the pump shaft 4 and the rotor portion 29. In this embodiment, the rotating sleeve 30 is made of graphite, which has the function of wear resistance and lubrication.

[0071] like Figure 3 As shown, the rotor 26 is located in the rotor cavity 16 and is sleeved on the pump shaft 4; a water gap 31 is formed between the rotor 26 and the first heat dissipation wall 17. In this embodiment, the rotor 26 is fixedly connected to the impeller 5 so that the brushless motor 6 can drive the impeller 5 to rotate around the pump shaft 4 in the impeller cavity 13. In this embodiment, the whole formed by the rotor 26 and the impeller 5 is allowed to slide axially relative to the pump shaft 4, and is allowed to rotate around the rotation axis relative to the pump shaft 4. In this embodiment, the connecting portion 3 is located above the rotating sleeve 30, which is used to limit the upward movement of the whole formed by the rotor 26 and the impeller 5. Specifically, when the impeller 5 rotates, the impeller 5 will drive the rotor 26 to move upward together until the rotating sleeve 30 directly or indirectly abuts the connecting portion 3.

[0072] like Figure 3 As shown, the electric control board 7 is installed in the electric control cavity 18 and is electrically connected to the stator 25 to control the stator 25 so that the brushless motor 6 can be started, stopped and the speed can be adjusted. In this embodiment, the electric control board 7 is attached to the second heat dissipation wall 19 through thermal conductive silicone. As is well known to those skilled in the art, the electric control board 7 is also connected to the external wiring terminal through the lead wire penetrating the lower housing 18 to obtain electrical energy and control signals from the outside.

[0073] like Figure 2 As shown, the gasket 8 is sleeved on the pump shaft 4 and is located between the connecting portion 3 and the rotating sleeve 30. The gasket 8 is generally made of wear-resistant material and is used to reduce the friction between the connecting portion 3 and the rotating sleeve 30.

[0074] like Figure 2 As shown, the lower limit member 9 is a clamping spring, and the lower limit member 9 is clamped on the pump shaft 4 so as to be fixedly connected to the pump shaft 4. The lower limit member 9 is used to limit the downward movement of the whole formed by the rotor 26 and the impeller 5.

[0075] like Figure 4 As shown, the electric water pump 1 in this embodiment will form a main water flow f1 and an internal circulation cooling water flow f2 during operation. The main water flow f1 is consistent with the prior art, and refers to the water flow that enters the impeller cavity 13 from the water inlet 14 and is pumped out to the water outlet 15 by the impeller 5. The following focuses on the internal circulation cooling water flow f2. As mentioned above, during the rotation of the impeller 5, a high-pressure area 32 will be formed at the outer edge of the impeller 5. In this embodiment, the high-pressure area 32 is located in the gap between the outer edge of the impeller 5 and the side cavity wall of the impeller cavity 13. The water flows from the high-pressure area 32, through the water gap 31, the rotor cavity 16 and the water channel 24 to the low-pressure area 33 and merges with the main water flow f1. The low-pressure area 33 is located near the water inlet 14, thereby forming the internal circulation cooling water flow f2. However, the internal circulation cooling water flow f2 is in liquid exchange with the main water flow f1. As described above, since the stator 25 is disposed outside the rotor cavity 16, and generally the stator 25 is adjacent to or in contact with the first heat dissipation wall 17, the water flow passing through the water gap 31 can take away the heat generated by the stator 25 during the operation of the electric water pump 1. As described above, the electric control board 7 also generates heat during the operation of the electric water pump 1, and the heat is conducted to the second heat dissipation wall 19 and taken away by the water flow that is about to enter the second end 23 of the pump shaft 4. Therefore, in this embodiment, the internal circulation cooling water flow f2 generated during the operation of the electric water pump 1 can effectively take away the heat generated by the stator 25 and the electric control board 7.

[0076] like Figure 5As shown, the center of mass of the whole formed by the impeller 5 and the rotor 26 must deviate from the axis of rotation during the actual assembly process. Since the diameter of the impeller 5 is larger than that of the rotor 26, and the mass of the rotor 26 is larger than that of the impeller 5, the equivalent center of mass of the whole formed by the impeller 5 and the rotor 26 during the rotation process is often located at the upper part of the rotor 26. Specifically, in this embodiment, when the impeller 5 rotates, the whole formed by the impeller 5 and the rotor 26 will move upward to the lower end of the connection part 3 through the gasket 8. At this time, since the equivalent center of mass of the whole formed by the impeller 5 and the rotor 26 must deviate, and the equivalent center of mass is located at the upper part of the rotor 26, the upper end of the rotating sleeve 30 will periodically collide with the pump shaft 4, forming a radial force F on the pump shaft 4, and the radial force changes continuously in direction and magnitude during the rotation process, causing the pump shaft 4 to produce flexural deformation and periodic vibration. In this embodiment, since the upper end of the pump shaft 4 is fixedly connected to the pump body 2 and the connecting portion 3 is very close to the upper part of the rotating sleeve 30, the flexural deformation of the pump shaft 4 caused by the radial force formed by the deviation of the equivalent center of mass of the upper part of the rotor 26 is very effectively weakened, so that the flexural deformation of the pump shaft 4 is smaller, the periodic vibration amplitude is smaller, and the noise and vibration are effectively reduced.

[0077] In this embodiment, since the connecting portion 3 is fixedly connected to the pump shaft 4 and to the cavity wall of the impeller cavity 13 of the upper housing 10, the offset between the rotation axis of the pump shaft 4 and the central axis of the impeller cavity 13 is smaller, which can improve the operating efficiency of the electric water pump 1 and avoid the impeller 5 hitting the inner wall of the upper housing 10.

[0078] This embodiment allows the rotor 26 and the impeller 5 to slide axially relative to the pump shaft 4, making it easier to assemble the rotor 26 and the impeller 5 as a whole to the pump shaft 4. The connection part 3 limits the upward movement of the rotor 26 and the impeller 5 as a whole, so that the connection part 3 has more functions besides connecting the pump shaft 4, and the structure is simpler. At the same time, as mentioned above, since the connection part 4 limits the upward movement of the rotor 26 and the impeller 5 as a whole, the fixed position of the pump shaft 4 and the pump body 2 is closer to the upper part of the rotor 26, which is beneficial to suppress the change of the flexural shape of the pump shaft 4.

[0079] In this embodiment, the gasket 8 is disposed between the connecting portion 3 and the rotor 26 , which can reduce the rotational friction between the rotor 26 and the connecting portion 3 and increase the life of the electric water pump 1 .

[0080] In this embodiment, the lower limit member 9 limits the downward movement of the rotor 26 and the impeller 5, so that the rotor 26 and the impeller 5 will not hit the connecting part 3 due to the long upward stroke during the rotation process, which is beneficial to reducing noise and increasing the service life. At the same time, it solves the problem that the rotor that moves freely along the axial direction of the pump shaft during the assembly process will be sucked away by the magnetic force.

[0081] In this embodiment, the connector 20 for being fixedly connected to the pump shaft 4 is connected to the upper housing 10 through the connecting ribs 21, and the connecting ribs 21 are distributed along the circumferential direction. The intervals between the connecting ribs 21 can allow water to flow smoothly from the water inlet 14 to the impeller 5. The circumferential distribution of the connecting ribs 21 can also ensure the position accuracy of the connector 20 in the impeller cavity 13, so that the offset between the rotation axis of the pump shaft 4 connected to the connector 20 and the central axis of the impeller cavity 13 is smaller, which can effectively improve the operation efficiency of the electric water pump 1.

[0082] In this embodiment, the connector 20 and the first end 22 of the pump shaft 4 form a bullet-shaped overall structure, and its upper surface is roughly conical or steamed bun-shaped. Such a shape is conducive to reducing the flow resistance of water flowing from the water inlet 14 to the impeller 5, thereby improving the operating efficiency of the electric water pump 1.

[0083] In this embodiment, the rotor portion 29 is rotatably connected to the pump shaft 4 via the rotating sleeve 30 , which can reduce the rotational friction between the rotor 26 and the pump shaft 4 and increase the life of the electric water pump 1 .

[0084] In this embodiment, the electric control board 7 is protected by the electric control chamber 18 and is easily electrically connected to the stator 25 , so that the electric water pump 1 has better product integrity.

[0085] In this embodiment, the connecting portion 3 is integrally formed with the upper shell 10, which can better ensure the position accuracy of the connecting portion 3 in the impeller chamber 13, so that the rotation axis of the pump shaft 4 connected to the connecting body 20 and the central axis of the impeller chamber 13 have a smaller deviation, which is beneficial to improving the operating efficiency of the electric water pump 1.

[0086] In this embodiment, the material of the connecting part 3 and the upper shell 10 is plastic, and the material of the pump shaft 4 is metal, so that the pump shaft 4 can be easily fixedly connected to the connecting part 3 by interference fit or other fitting methods, and the pump shaft 4 has higher strength and is less likely to generate noise due to vibration.

[0087] In this embodiment, the pump shaft 4 is provided with a water passage 24 along the extension direction, and the high-pressure area 32 is connected to the low-pressure area 33 through the rotor cavity 16 and the water passage 24, so that an internal circulation cooling flow channel can be established inside the electric water pump 1, so that water flows from the high-pressure area 32 to the low-pressure area 33 through the internal circulation cooling flow channel to form an internal circulation cooling water flow f2, which is beneficial to the heat dissipation of the stator 25 and the electronic control board 7, and can increase the service life of the electric water pump 1.

[0088] In this embodiment, a water gap 31 is formed between the first heat dissipation wall 17 and the rotor 26. When the internal circulating cooling water flow f2 passes through the water gap 31, the flow velocity is accelerated due to the Venturi effect, making it easier to take away the heat generated by the stator 25 during the operation of the electric water pump 1.

[0089] In this embodiment, the second end 23 of the pump shaft 4 is close to the second heat dissipation wall 19, forcing the internal circulating cooling water flow f2 to quickly pass through the second heat dissipation wall 19, and the electronic control board 7 is close to the second heat dissipation wall 19, which makes it easier to take away the heat generated by the electronic control board 7 during the operation of the electric water pump 1.

[0090] Embodiment 2

[0091] See also Figure 6 , Figure 6 The electric water pump 1 in the second embodiment is shown.

[0092] like Figure 6 As shown, the difference between this embodiment and the first embodiment is that, in this embodiment, the material of the upper shell 10 is plastic, and the material of the connecting part 3 is made of a material with higher strength than plastic, such as metal. The connecting part 3 not only includes a connecting body 20 and four connecting ribs 21, but also includes an insert part 34 corresponding to the four connecting ribs 21. In this embodiment, one end of the four connecting ribs 21 is connected to the connecting body 20 as a whole, and the other end is connected to the insert part 34 as a whole. When the upper shell 10 is injection molded, the insert part 34 is placed in the mold of the connecting part 3, so that the upper shell 10 and the connecting part 3 in this embodiment are insert-injected and molded as a whole. In this embodiment, the material of the pump shaft 4 can be metal or plastic.

[0093] In this embodiment, the connecting part 3 and the upper shell 10 are integrally formed by insert injection molding, and the upper shell 10 is made of plastic, and the connecting part 3 is made of metal. Not only is the connecting part 3 firmly connected to the upper shell 10, but the strength and processing accuracy of the connecting part 3 can be guaranteed, so that the rotation axis of the pump shaft 4 connected to the connecting part 3 deviates less from the central axis of the impeller chamber 13, which can effectively improve the operating efficiency of the electric water pump 1.

[0094] The other parts of the second embodiment are the same as those of the first embodiment, and thus also have the corresponding effects of the first embodiment.

[0095] Embodiment 3

[0096] The difference between the third embodiment and the first embodiment is that the upper shell 10, the connecting part 3 and the pump shaft 4 in the third embodiment are all made of plastic material and are integrally injection molded, so the processing is simpler, the assembly efficiency can be improved, and the position accuracy of the pump shaft 4 is easier to ensure.

[0097] The other parts of the third embodiment are the same as those of the first embodiment, and thus also have the corresponding effects of the first embodiment.

[0098] Embodiment 4

[0099] The difference between the fourth embodiment and the first embodiment is that the second heat dissipation wall 19 in the fourth embodiment extends toward the water inlet 14 to form a limiting portion 35. In this embodiment, the limiting portion 35 is clearance-matched with the second end 23 of the pump shaft 4 and radially limits the pump shaft 4. Of course, in other embodiments, the limiting portion 35 only needs to be located in the rotor cavity 16 and below the rotor 26. The limiting portion 35 in this embodiment has a water hole 36 on its annular wall, and the internal circulating cooling water flow f2 can flow from the rotor cavity 16 through the water hole 36 into the water channel 24.

[0100] In the present embodiment, since the portion of the pump shaft 4 extending into the impeller chamber 13 is fixedly connected to the connecting portion 3, the vibration of the pump shaft 4, especially the second end 23 thereof, is smaller. If the second end 23 thereof needs to be radially limited, the strength of the limiting portion 35 does not need to be too high. Therefore, the radial wall thickness of the limiting portion 35 can be set to be thinner, which is beneficial to the heat dissipation of the electronic control board 7.

[0101] This embodiment can not only further reduce the flexural deformation of the second end 23 of the pump shaft 4, thereby further reducing the noise generated by the vibration of the pump shaft 4, but also does not hinder the flow of the internal circulation cooling water flow f2.

[0102] The other parts of the fourth embodiment are the same as those of the first embodiment, and thus also have the corresponding effects of the first embodiment.

[0103] The above specification and description of the embodiments are used to explain the protection scope of the present application, but do not constitute a limitation on the protection scope of the present application.

Claims

1. An electric water pump, comprising: A pump body (2) is provided with a water inlet (14), a water outlet (15), an impeller chamber (13) and a rotor chamber (16); the water inlet (14) and the water outlet (15) are connected to the impeller chamber (13), and the rotor chamber (16) is axially connected to the impeller chamber (13); A pump shaft (4), a first end (22) of which is located in the impeller chamber (13) and a second end (23) of which is located in the rotor chamber (16); a brushless motor (6), comprising a rotor (26) and a stator (25), wherein the rotor (26) is located in the rotor cavity (16) and is rotationally connected to the pump shaft (4), and the stator (25) is fixedly connected to the pump body (2) and is disposed outside the rotor cavity (16); and An impeller (5) located in the impeller chamber (13) and fixedly connected to the rotor (26); Its characteristics include: A connecting portion (3) connects the cavity wall of the impeller cavity (13) and the portion of the pump shaft (4) extending into the impeller cavity (13) so that the pump shaft (4) and the pump body (2) are fixedly connected.

2. An electric water pump as claimed in claim 1, characterized in that: The rotor (26) and the impeller (5) are allowed to slide axially relative to the pump shaft (4), and the connecting portion (3) limits the upward movement of the rotor (26) and the impeller (5).

3. An electric water pump as claimed in claim 2, characterized in that: It also includes a gasket (8) and a lower limit member (9); the gasket (8) is arranged between the connecting portion (3) and the rotor (26); the lower limit member (9) is fixedly connected to the pump shaft (4) and is used to limit the downward movement of the rotor (26) and the impeller (5).

4. An electric water pump as claimed in claim 1, characterized in that: The pump body (2) is further provided with a limiting portion (35), the limiting portion (35) being located in the rotor cavity (16) and below the rotor (26), the limiting portion (35) being clearance-matched with the pump shaft (4) and limiting the radial position of the pump shaft (4).

5. An electric water pump as claimed in claim 1, characterized in that: The connecting portion (3) is provided with a connecting body (20) and at least two connecting ribs (21); the connecting body (20) is used to fix the pump shaft (4); one end of the connecting rib (21) is fixedly connected to the connecting body (20) and the other end is fixedly connected to the cavity wall of the impeller cavity (13); and each of the connecting ribs (21) is arranged along the circumferential direction.

6. An electric water pump as claimed in claim 5, characterized in that: The connector (20) is fixedly connected to the first end (22) of the pump shaft (4), so that the whole formed by the two is in the shape of a bullet head facing the water inlet (14).

7. An electric water pump as claimed in claim 1, characterized in that: The rotor (26) comprises a rotor portion (29) and a rotating sleeve (30); the rotor portion (29) and the stator (25) constitute a brushless motor (6); the rotating sleeve (30) is clearance-matched with the pump shaft (4) and is fixedly connected to the rotor portion (29).

8. An electric water pump according to any one of claims 1 to 7, characterized in that: The electric water pump (1) further comprises an electric control panel (7); The pump body (2) is further provided with an electric control chamber (18), wherein the electric control chamber (18) is adjacent to the rotor chamber (16) and is axially away from the impeller chamber (13); The electric control board (7) is installed in the electric control chamber (18) and is electrically connected to the stator (25) to control the stator (25).

9. An electric water pump as claimed in claim 8, characterized in that: The pump body (2) comprises an upper shell (10), a middle shell (11) and a lower shell (12); the upper shell (10) is watertightly fixed to the middle shell (11); the lower shell (12) is fixed to the middle shell (11); the impeller chamber (13), the water inlet (14) and the water outlet (15) are formed in the upper shell (10); the rotor chamber (16) is formed in the middle shell (11); and the middle shell (11) and the lower shell (12) are enclosed to form the electric control chamber (18).

10. An electric water pump as claimed in claim 9, characterized in that: The connecting portion (3) and the upper shell (10) are integrally formed.

11. An electric water pump as claimed in claim 10, characterized in that: The material of the upper shell (10) is plastic, the material of the connecting portion (3) is metal, and the connecting portion (3) and the upper shell (10) are integrally formed by insert injection molding.

12. An electric water pump as claimed in claim 10, characterized in that: The upper shell (10), the connecting portion (3) and the pump shaft (4) are integrally formed.

13. The electric water pump according to claim 8, characterized in that: The pump shaft (4) is provided with a water passage (24) along its extension direction, and a high-pressure area (32) is formed between the impeller (5) and the cavity wall of the impeller cavity (13). The high-pressure area (32) is connected to a low-pressure area (33) close to the water inlet (14) through the rotor cavity (16) and the water passage (24).

14. An electric water pump as claimed in claim 13, characterized in that: The side cavity wall of the rotor cavity (16) forms a first heat dissipation wall (17), and a water gap (31) is formed between the first heat dissipation wall (17) and the rotor (26). The water gap (31) is used to connect the high-pressure area (32) and the water passage (24).

15. An electric water pump as claimed in claim 13, characterized in that: The cavity wall between the rotor cavity (16) and the electric control cavity (18) forms a second heat dissipation wall (19), the second end (23) of the pump shaft (4) is close to the second heat dissipation wall (19), and the electric control board (7) is close to the second heat dissipation wall (19).

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