An electronic water pump that can promote circulation after shutdown

Abstract

This invention discloses an electronic water pump that can promote circulation after shutdown, including a pump casing, a motor assembly, an inlet, an outlet, and a circuit board. An electromagnetic clutch assembly and an energy storage structure are sequentially arranged between the rotor and impeller on the rotating shaft. When the motor is running, the electromagnetic clutch assembly transmits the rotor torque to the energy storage structure. When the pump stops or is powered off, the electromagnetic clutch assembly releases, cutting off the rotor's braking force on the energy storage structure. This allows the energy storage structure to continue rotating the shaft and impeller for a period of time due to its rotational inertia, forming a short-term circulation. This short-term circulation covers the window of concentrated bubble formation during the residual heat phase of shutdown, promptly removing bubbles from hot spots and local high points and dispersing them into the circuit, reducing the risks of heat transfer attenuation, temperature surge, flow instability, and abnormal noise caused by bubble accumulation. Simultaneously, the release of the clutch reduces the impact of reverse rotation on the circuit.

Description

Technical Field

[0001] This invention relates to the field of vehicle thermal management technology, and more specifically to an electronic water pump that can promote circulation after shutdown. Background Technology

[0002] Automotive thermal management systems typically use electric water pumps to circulate coolant between the engine block, cylinder head, and related heat exchange components to achieve heat transfer and temperature control. Most existing electric water pumps employ a centrifugal pump structure, where coolant is drawn in through the impeller center and discharged through the outer periphery of the volute. To improve electrical reliability and reduce the risk of coolant ingress, some electric water pumps adopt a dry-chamber structure. In this structure, the motor assembly and drive circuitry are located within the dry chamber, while the impeller is located within the coolant chamber. The two are connected by a through-shaft, and a dynamic seal assembly isolates the coolant chamber from the dry chamber. The dynamic seal refers to a structure that maintains a seal even when the shaft rotates, preventing coolant from entering the dry chamber along the shaft.

[0003] In cooling circuits, the entry of gas and the formation of bubbles can easily accumulate at local high points in the circuit or near the pump body, leading to poor liquid filling within the pump chamber. This results in reduced pumping capacity, unstable flow, and abnormal noise, and in severe cases, may even cause the pump to run dry and affect system stability. Existing technologies address the gas problem in cooling circuits primarily by focusing on the entry and exit of external air. For example, patent CN202122395182.5 proposes an electronic water pump with automatic gas detection and venting capabilities. It addresses the issue of reduced efficiency and even pump dry running caused by air entering the cooling circuit, and improves operational stability by using a gas detection and venting structure to expel the gas. Its focus is on removing free gas that has accumulated at specific locations from the circuit.

[0004] Besides the entry of external gases, when the vehicle suddenly stops or the system loses power, the electric water pump stops outputting torque, forcibly interrupting circulation. However, the engine and high-temperature components on the exhaust side continue to release heat after shutdown, and this residual heat flows back into the coolant, causing localized areas to continue heating up for a short period after shutdown. This localized temperature rise can cause two types of bubbles internally: vaporization, where the coolant turns into gas upon heating and forms bubbles; and the precipitation of dissolved gases, where gases originally dissolved in the coolant precipitate from the liquid due to the increased temperature, forming tiny bubbles. A small number of bubbles in the coolant are acceptable from an engineering perspective. However, in the absence of forced flow conditions during shutdown, a short period of concentrated production of tiny bubbles can lead to their gradual aggregation and merging near hot spots or localized high points in the circuit, forming bubble accumulation. Bubble accumulation reduces the contact between the coolant and the metal wall, decreasing localized heat exchange capacity and making it difficult for the localized temperature to drop for an extended period. Simultaneously, bubble accumulation can cause localized stagnation and increased flow resistance, making the circuit flow more unstable and potentially accompanied by abnormal noise and flow instability, thus increasing the uncertainty of the temperature state during shutdown.

[0005] Therefore, an electronic water pump structure or operating mode is needed to carry newly generated bubbles away from the vicinity of hot spots and local high points with the flow, reducing the problem of overheated bubbles staying and merging locally, thereby suppressing the local heat transfer attenuation and temperature surge caused by bubble accumulation, and mitigating the risk of further abnormal noise and flow instability caused by bubble aggregation. Summary of the Invention

[0006] The technical problem this invention aims to solve is that after a vehicle suddenly stops or the electric water pump loses power, high-temperature components such as the engine and exhaust side continue to draw residual heat back into the coolant. This causes vaporized and dissolved gases to rapidly form a large number of tiny bubbles. These newly generated bubbles tend to accumulate and coalesce near the pump body and at local high points in the circuit, leading to localized heat exchange deterioration. Furthermore, this can cause unstable flow and abnormal noise during subsequent restarts. Therefore, an electric water pump structure is needed that can maintain coolant circulation for a short period after shutdown, so as to promptly remove the concentrated bubbles from the hot spot area and suppress bubble accumulation and its adverse effects.

[0007] To achieve the above objectives, the present invention provides an electronic water pump that can promote circulation after shutdown, comprising a pump housing, a motor assembly, and an inlet and an outlet disposed on the pump housing. The pump housing consists of an upper housing and a lower housing. The upper housing forms a pump chamber communicating with the inlet and outlet, and the lower housing forms a mounting cavity. A connecting groove is formed on the outer periphery of the lower housing to accommodate a connector for fixed connection between the upper and lower housings. The motor assembly is mounted in the mounting cavity and includes a rotor, a stator arranged around the rotor, and a first shaft section fixedly connected to the rotor. The electronic water pump also includes a second shaft section coaxially arranged with the first shaft section. One end of the second shaft section extends into the pump chamber and is connected to an impeller for driving coolant from the inlet to the outlet. An electrical control housing is formed on the side of the pump housing away from the pump chamber, and a circuit board electrically connected to the motor assembly is installed in the electrical control housing. Unlike existing electronic water pumps, this system features an electromagnetic clutch assembly between the first and second shaft sections, with an energy storage structure on the second shaft section. The electromagnetic clutch assembly connects to both shaft sections, transmitting rotor torque from the first to the second shaft section during motor operation. When the motor stops or is de-energized, it releases torque transmission between the first and second shaft sections, allowing them to rotate relative to each other. This disconnects the rotor's braking effect on the second shaft section and the energy storage structure, allowing the energy storage structure to continue rotating the second shaft section and impeller for a short period after shutdown using its own inertia. This maintains short-term coolant circulation during shutdown, carrying newly formed bubbles away from hot spots and localized high points. This technical solution, by introducing controllable inertial energy storage and clutch transmission within the pump, allows the system to achieve a gradually decreasing flow rate decay curve without external power after shutdown, which helps mitigate temperature fluctuations and suppress bubble accumulation.

[0008] Furthermore, the electromagnetic clutch assembly includes an excitation coil, a fixed iron core, an armature disc, a reset component, a friction disc, and a clutch mounting base. The fixed iron core is fixedly mounted on the pump casing, the excitation coil is sleeved on the outside of the fixed iron core, the clutch mounting base is circumferentially fixedly connected to the first shaft section and rotates with the first shaft section, the friction disc is circumferentially fixedly connected to the second shaft section and rotates integrally with the second shaft section, the armature disc is located on one side of the friction disc and is allowed to move axially, and the armature disc and the clutch mounting base are circumferentially locked so that the armature disc rotates synchronously with the clutch mounting base. When the excitation coil is energized, the armature disc is attracted to the friction disc and pressed against it, transmitting the torque of the first shaft section to the second shaft section through the clutch mounting base, armature disc, and friction disc, achieving reliable connection under normal operating conditions; this structure ensures driving efficiency and facilitates rapid release of torque transmission between the first and second shaft sections when power is off, thereby avoiding continuous braking action from the motor side to the impeller side.

[0009] Preferably, the reset element is an elastic element, with one end connected to the pump casing and the other end connected to the armature disc. The reset element applies an axial reset force to the armature disc and allows the armature disc to rotate with the clutch mounting seat. When the excitation coil is de-energized, it pulls the armature disc away from the friction disc, thereby releasing the torque transmission between the first and second shaft sections and allowing the second shaft section to rotate freely relative to the first shaft section under inertia. By setting an elastic reset element, the impeller-side shaft system can be quickly released at the moment of shutdown, allowing it to continue rotating with less resistance, which is beneficial to improving the duration and effect of post-shutdown circulation.

[0010] Furthermore, the energy storage structure includes a mounting sleeve fitted onto the second rotating shaft section and an inertia ring fixed to the outer circumference of the mounting sleeve. The mounting sleeve is fixedly connected to the second rotating shaft section in the circumferential direction, allowing the inertia ring to rotate integrally with the second rotating shaft section to form rotational inertia energy storage. By adding an inertia ring to the second rotating shaft section, the total rotational inertia of the system can be increased without changing the motor body and impeller structure, enabling greater kinetic energy to be obtained using the same angular velocity after shutdown, thereby extending the natural coasting time of the water pump.

[0011] Preferably, the inertia ring has multiple cavities arranged circumferentially, and each cavity contains a ball bearing that can rotate within its respective cavity. On the one hand, with the same external dimensions, the ball bearings can increase the local mass concentration and the equivalent rotation radius, further enhancing the rotational inertia of the energy storage structure. On the other hand, the rotatable arrangement of the ball bearings within the cavities facilitates smooth torque distribution during start-up and shutdown, reduces rigid impact between the inertia ring and the mounting sleeve, thereby improving start-up and shutdown response and reducing noise.

[0012] Furthermore, a bearing housing for supporting the energy storage structure is provided inside the pump casing. The bearing housing includes a support arm connected to the pump casing and a bearing mounted on the support arm. The outer ring of the bearing is fixedly connected to the support arm, and the inner ring of the bearing is rotatably engaged with the mounting sleeve to provide radial support for the second shaft section when the energy storage structure rotates. By separately providing a bearing housing near the energy storage structure, the additional burden of the energy storage structure's mass on the motor end support can be reduced, improving the overall shaft system's rigidity and lifespan, and ensuring concentricity and stability during the free rotation phase after shutdown.

[0013] Furthermore, a spline is provided on the second rotating shaft section, and a spline sleeve is provided inside the mounting sleeve. The spline sleeve and the spline engage, enabling the energy storage structure and the second rotating shaft section to reliably transmit torque in the circumferential direction and facilitating axial assembly and disassembly. The spline connection method allows for axial assembly freedom while ensuring torque transmission capability, facilitating the optimization of the assembly sequence of the energy storage structure and impeller components, and also benefiting maintenance and replacement.

[0014] Preferably, the impeller is mounted at the end of the second shaft section and fixedly connected with a spline, so that when the energy storage structure drives the second shaft section to rotate, the impeller rotates synchronously to maintain coolant circulation during shutdown. This arrangement allows the inertial energy storage to act directly on the impeller without the need for additional intermediate transmission components, reducing energy loss and simplifying the structure.

[0015] Furthermore, a first sealing ring is provided between the mounting cavity and the pump chamber, and a second sealing ring is provided between the mounting cavity and the electrical control housing. The first and second sealing rings are used to limit the leakage of coolant towards the motor assembly and circuit board. By arranging sealing rings at critical interfaces, the internal pressure and medium environment of the pump body can be kept stable during the shutdown and circulation process, preventing coolant from entering the dry chamber due to pressure fluctuations caused by inertial rotation, thus ensuring the reliability of the motor and electronic components.

[0016] In addition, the upper housing forms an inlet, an outlet, and a pump chamber, while the lower housing forms an mounting cavity, a connecting groove, and an electrical control housing. The connecting groove in the lower housing accommodates a connector, and the upper housing is fixedly connected to the lower housing via the connector. The circuit board is installed in the electrical control housing and electrically connected to the motor assembly and external controller. This housing structure facilitates functional partitioning and assembly of the pump chamber, motor assembly, and circuit board area.

[0017] This invention utilizes an electromagnetic clutch assembly between the first and second shaft sections, and an energy storage structure on the second shaft section. This allows the electric water pump to continue rotating the impeller using the rotational inertia of the energy storage structure after the motor stops or is powered off, maintaining forced circulation for a period during the residual heat release phase after shutdown. After shutdown, the engine and exhaust-side high-temperature components only release heat to the coolant for a short time, during which vaporization bubbles and dissolved gas bubbles are formed. This invention utilizes this circulation-promoting time to promptly remove newly formed fine bubbles from hot spots such as the cylinder head and exhaust side, as well as localized high points in the circuit, preventing them from remaining, growing, and accumulating in stagnant conditions, thereby mitigating localized heat transfer deterioration and temperature surges.

[0018] During circulation, bubbles are transported to cooler, larger-volume components such as radiators and expansion tanks. Some bubbles dissolve or condense and disappear as the coolant temperature drops, while the remaining bubbles are elongated and dispersed throughout the longer flow path, transforming into a sparse bubble band distributed throughout the system. As residual heat is gradually released during shutdown, new bubble sources are essentially eliminated from the system. Furthermore, due to the reduced temperature and altered flow conditions, even if residual bubbles remain, they are unlikely to aggregate into large-volume bubble deposits in the same localized area, reducing the risk of localized overheating, boiling, and abnormal noise during shutdown. In addition, the electromagnetic clutch assembly releases torque transmission between the first and second shaft sections after power is cut off. The impeller-side shaft system is no longer rigidly constrained by the motor side, reducing the impact on the motor side when the impeller rotates in reverse due to external pressure pulsations or natural circulation. This reduces the impact of reverse rotation on the circuit, improving the operational stability and durability of the electric water pump during shutdown. Attached Figure Description

[0019] Figure 1 This is a schematic diagram of the overall structure of an electronic water pump that can promote circulation after shutdown.

[0020] Figure 2 This is a schematic diagram of an explosion of an electronic water pump that can promote circulation after shutdown.

[0021] Figure 3 This is a cross-sectional schematic diagram of an electronic water pump that can promote circulation after shutdown.

[0022] Figure 4 This is a schematic diagram of the electromagnetic clutch structure in an electronic water pump that can promote circulation after shutdown.

[0023] Figure 5 This is an exploded view of the rotating shaft and energy storage structure of an electronic water pump that can promote circulation after shutdown.

[0024] Figure 6 This is a cross-sectional view of the inertia ring in an electronic water pump that can promote circulation after shutdown.

[0025] Attached icon numbers: 1. Pump casing; 11. Upper casing; 12. Lower casing; 13. Inlet; 14. Outlet; 15. Mounting cavity; 16. Connecting groove; 161. Connecting piece; 2. Motor assembly; 21. Impeller; 22. Shaft; 221. Spline; 23. Rotor; 24. Stator; 25. Circuit board; 3. Electromagnetic clutch assembly; 31. Excitation coil; 32. Fixed iron core; 33. Armature plate; 34. Reset piece; 35. Friction plate; 36. Clutch mounting seat; 4. Energy storage structure; 41. Inertia ring; 411. Ball bearing; 42. Mounting sleeve; 43. Spline sleeve; 44. Bearing seat; 441. Support arm; 442. Bearing inner ring; 5. Sealing ring; 51. First sealing ring; 52. Second sealing ring. Detailed Implementation

[0026] The technical solutions of this application will now be clearly and completely described with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. The components of this application described and shown in the accompanying drawings can generally be arranged and designed in various different configurations. Therefore, the following detailed description of the embodiments of this application provided in the accompanying drawings is not intended to limit the scope of the claimed application, but merely to illustrate selected embodiments of this application.

[0027] like Figures 1 to 6 As shown, this invention provides an electronic water pump that can promote circulation after shutdown, used in a vehicle thermal management system to drive coolant circulation. It should be noted that this embodiment is only used to explain the technical solution of this invention and is not intended to limit the scope of protection of this invention; any equivalent substitutions made by those skilled in the art to the structural form or assembly method without departing from the concept of this invention should fall within the scope of protection of this invention.

[0028] like Figure 1 and Figure 2As shown, the electronic water pump includes a pump housing 1, a motor assembly 2, and an inlet 13 and an outlet 14 disposed on the pump housing 1. The pump housing 1 is composed of an upper housing 11 and a lower housing 12. After the upper housing 11 and the lower housing 12 are joined together, they enclose a closed housing space and realize functional partitioning. A pump chamber communicating with the inlet 13 and the outlet 14 is formed inside the upper housing 11, and an installation cavity 15 is formed inside the lower housing 12. A connecting groove 16 is formed on the outer periphery of the lower housing 12. The connecting groove 16 is used to accommodate the connector 161 to realize the fixed connection between the upper housing 11 and the lower housing 12. An electronic control accommodating part is also formed on the side of the pump housing 1 away from the pump chamber to accommodate and protect the circuit board 25. By arranging the pump chamber in the upper housing 11 and the mounting chamber 15 and the electrical control housing in the lower housing 12, the coolant can flow mainly in the pump chamber. The motor assembly 2 and the circuit board 25 are located in the relatively dry areas formed by the mounting chamber 15 and the electrical control housing, respectively. This structural partitioning reduces the potential impact of the coolant on the circuit board 25. Especially when the energy storage structure 4 drives the impeller 21 to continue rotating after shutdown, and pressure fluctuations and liquid disturbances still exist in the pump chamber, the above partitioning structure helps to improve the electrical reliability of the whole machine.

[0029] The upper housing 11 and the lower housing 12 are fixedly connected by a connector 161. Specifically, the connector 161 can be a fastener such as a screw. The connector 161 is accommodated in the connecting groove 16 and passes through the corresponding threaded holes of the upper housing 11 and the lower housing 12, and is screwed on. Under the pressing action of the connector 161, the upper housing 11 and the lower housing 12 achieve a uniform circumferential fit, thereby ensuring the relative position stability between the pump chamber, the mounting chamber 15, and the electronic control housing. This connection method facilitates positioning and disassembly maintenance during assembly, and at the same time ensures that the housing connection surface is not prone to gap changes under vehicle operation vibration and thermal cycling conditions, which is conducive to the long-term sealing effect stability of the sealing ring 5 and reduces the risk of coolant leakage to the circuit board 25 area.

[0030] like Figure 1As shown, the inlet 13 is located at one end of the upper housing 11, and the outlet 14 is located at another position on the upper housing 11 and communicates with the pump chamber. The inlet 13 is connected to the incoming coolant line of the vehicle's cooling circuit, and the outlet 14 is connected to the line leading to the engine block, cylinder head, or other heat exchange components, so that the coolant enters the pump chamber through the inlet 13 under the push of the impeller 21 and is output through the outlet 14. This flow path arrangement enables the electric water pump to establish a stable forced circulation during normal operation; more importantly, during the shutdown residual heat stage targeted by this invention, the coolant will generate vaporization bubbles or fine bubbles formed by dissolved gas precipitation in a short time due to residual heat reinjection. If the forced flow is completely lost after shutdown, the fine bubbles are more likely to stay near local high points or hot spots and gradually accumulate to form bubble accumulation. To suppress the aforementioned bubble accumulation, the present invention utilizes the electromagnetic clutch assembly 3 and the energy storage structure 4 described later to achieve short-term circulation after shutdown, enabling the pump chamber to maintain a certain flow driving force and promptly remove the bubbles generated in a short period of time from the local area, thereby addressing the technical problem of short-term bubble accumulation after shutdown.

[0031] like Figure 2 and Figure 3 As shown, the mounting cavity 15 formed inside the lower housing 12 is used to accommodate the motor assembly 2, and the electrical control housing formed on the side of the pump housing 1 away from the pump cavity is used to mount the circuit board 25. The circuit board 25 is mounted in the electrical control housing and is electrically connected to the motor assembly 2. The electrical connection can be achieved through wires, plug-in terminals, or board-end connections, enabling the circuit board 25 to provide driving power to the motor assembly 2 and realize speed control and operating status control. The electrical control housing forms a shell shield between itself and the outside world, which can reduce the risk of external moisture, mud, etc., intruding into the circuit board 25, thereby improving the durability and reliability of the entire electronic water pump in the vehicle environment. Especially in the post-shutdown circulation stage of the present invention, the energy storage structure 4 drives the impeller 21 to continue rotating, and there is still a certain flow and pressure change in the pump cavity. With the cooperation of the sealing structure described later, the electrical control housing helps to avoid the impact of pressure fluctuations on the circuit board 25 causing coolant leakage, further corresponding to the improvement effect on circuit reliability emphasized by the present invention. It should be noted that the connecting groove 16 is located on the outer periphery of the lower housing 12 and is used to accommodate the connector 161. It mainly undertakes the function of connecting the housing and transmitting the force during assembly. The connecting groove 16 is not the installation space of the circuit board 25, nor does it involve the communication relationship with the mounting cavity 15.

[0032] like Figure 3As shown, the motor assembly 2 includes a rotor 23, a stator 24 arranged around the rotor 23, and a first shaft section fixedly connected to the rotor 23. The electric water pump also includes a second shaft section coaxially arranged with the first shaft section. The stator 24 is fixedly installed in the mounting cavity 15. The fixing method can be one or a combination of interference fit, positioning step limiting fit, or adhesive fixing, so that the stator 24 remains stable and does not rotate relative to the pump housing 1. The rotor 23 is located inside the stator 24 and is fixedly connected to the first shaft section. The fixed connection can be achieved by interference fit, key connection, or end fastening, so that the rotor 23 and the first shaft section rotate synchronously in the circumferential direction. The second shaft section is arranged along the axial direction of the pump housing 1. One end of the second shaft section extends into the pump cavity and is connected to an impeller 21, so that when the second shaft section is driven, it drives the impeller 21 to rotate to circulate the coolant. It is important to emphasize that in traditional electric water pumps, after shutdown or power failure, the rotor 23 often exerts significant braking on the impeller side due to electromagnetic damping, reluctance torque, and the braking effect of related circuits on the circuit board 25. This causes the impeller 21 to stop quickly, resulting in a lack of flow conditions during the residual heat phase of shutdown, and bubbles generated in a short period of time are more likely to accumulate in localized areas. This invention addresses this by installing an electromagnetic clutch assembly 3 between the first and second shaft sections and an energy storage structure 4 on the second shaft section. This allows the rotor and impeller sides to release torque transmission and allow relative rotation after shutdown, providing short-term circulation conditions for the residual heat phase of shutdown from a structural perspective.

[0033] like Figure 3 , Figure 4 and Figure 5 As shown, an electromagnetic clutch assembly 3 is provided between the first and second shaft sections, and an energy storage structure 4 is provided on the second shaft section. The electromagnetic clutch assembly 3 is connected to the first and second shaft sections respectively, and is used to transmit the torque of the rotor 23 from the first shaft section to the second shaft section when the motor assembly 2 is working normally, so that the second shaft section drives the impeller 21 to circulate the coolant, thereby ensuring normal pumping efficiency; when the motor assembly 2 stops or is de-energized, the electromagnetic clutch assembly 3 releases the torque transmission between the first and second shaft sections and allows them to rotate relative to each other, so as to cut off the braking effect of the rotor 23 on the second shaft section and the energy storage structure 4, so that the energy storage structure 4 can continue to drive the second shaft section and the impeller 21 to rotate for a period of time using its own rotational inertia, thereby promoting the formation of short-term circulation of coolant during the residual heat stage of shutdown, timely carrying and transporting the bubbles generated in a short time, reducing the probability of bubbles staying and accumulating near hot spots or local high points, and achieving the core technical effect of the present invention.

[0034] like Figure 4As shown, the electromagnetic clutch assembly 3 includes an excitation coil 31, a fixed iron core 32, an armature disk 33, a reset component 34, a friction disk 35, and a clutch mounting base 36. The fixed iron core 32 is fixedly mounted on the pump housing 1, specifically on the inner wall of the mounting cavity 15 formed by the lower housing 12 or on a corresponding positioning structure. The fixing method can be a fastening connection or an embedded fixing, so that the fixed iron core 32 remains stationary relative to the pump housing 1 and is coaxially arranged with the first rotating shaft section and the second rotating shaft section. The excitation coil 31 is sleeved on the outside of the fixed iron core 32 and is electrically connected to the circuit board 25. The circuit board 25 controls the excitation coil 31 to be energized or de-energized during the operation of the motor assembly 2, thereby realizing the engagement or release of the electromagnetic clutch assembly 3. The clutch mounting base 36 is circumferentially fixedly connected to the first rotating shaft section and rotates with the first rotating shaft section. The clutch mounting base 36 and the first rotating shaft section can be circumferentially fixed by spline fit, interference fit, or end locking method. The friction disc 35 is circumferentially fixedly connected to the second rotating shaft section and rotates integrally with the second rotating shaft section. The friction disc 35 and the second rotating shaft section can be fastened with screws, riveted, or integrally formed, so that the friction disc 35 can reliably withstand the frictional torque during clutch transmission without relative slippage. The armature disc 33 is located on one side of the friction disc 35. The armature disc 33 is allowed to move axially to achieve engagement and disengagement. At the same time, the armature disc 33 and the clutch mounting seat 36 are in a circumferential upper limit engagement so that the armature disc 33 rotates synchronously with the clutch mounting seat 36, thereby forming a clutch transmission link that can transmit torque circumferentially and move axially.

[0035] When the motor assembly 2 is operating normally, the circuit board 25 energizes the excitation coil 31. The excitation coil 31 generates a magnetic field at the fixed iron core 32. Under the action of magnetic force, the armature disk 33 is attracted to the friction disk 35 and pressed against it, forming a reliable frictional contact. This transmits the torque of the first shaft section to the second shaft section via the clutch mounting seat 36, the armature disk 33, and the friction disk 35. At this time, the second shaft section drives the impeller 21 to circulate the coolant, ensuring the coolant flow rate requirement under normal operating conditions. This working method ensures that the electromagnetic clutch assembly 3 can form an effective torque transmission path when energized, enabling the present invention to still meet the pumping capacity requirements of the vehicle thermal management system after the introduction of the energy storage structure 4, and avoiding a reduction in normal operating efficiency due to the addition of the structure.

[0036] like Figure 4As shown, the reset member 34 is an elastic element, with one end connected to the pump housing 1 and the other end connected to the armature disk 33. The reset member 34 can be a leaf spring, a wave spring, or an elastic support structure. The reset member 34 is used to apply an axial reset force to the armature disk 33 and allow the armature disk 33 to rotate with the clutch mounting seat 36. When the excitation coil 31 is de-energized, the reset member 34 applies a reset force to the armature disk 33, pulling the armature disk 33 away from the friction disk 35, thereby releasing the clamping contact between the armature disk 33 and the friction disk 35 or forming a gap, thereby releasing the torque transmission between the first shaft section and the second shaft section and allowing the second shaft section to rotate freely relative to the first shaft section under inertia. Since the armature disk 33 is disengaged from the friction disk 35, the rotor 23 and its associated motor magnetic reluctance effect, and the electromagnetic braking effect that the circuit board 25 may form, no longer directly act on the second shaft section and the energy storage structure 4 through the clutch link, thereby achieving the effect of cutting off the braking action after shutdown required by the present invention, and providing the necessary flow conditions for bubble migration.

[0037] like Figure 3 , Figure 5 and Figure 6 As shown, the energy storage structure 4 includes a mounting sleeve 42 sleeved on the second rotating shaft section and an inertia ring 41 fixed to the outer periphery of the mounting sleeve 42. The mounting sleeve 42 is fixedly connected to the second rotating shaft section in the circumferential direction, so that the inertia ring 41 rotates integrally with the second rotating shaft section to form rotational inertia energy storage. By introducing the inertia ring 41 on the second rotating shaft section, the rotational inertia of the impeller-side shaft system can be significantly increased without changing the structure of the impeller 21. This allows the energy storage structure 4 to maintain rotation with its own inertia after the motor assembly 2 is powered off, thereby generating a short-term circulation during the residual heat stage of shutdown. This circulation corresponds precisely to the characteristic of bubble concentrated generation in a short time due to residual heat. It can carry the bubbles away from the local area within the critical time window of bubble generation, preventing them from accumulating and achieving the key technical effect of the present invention.

[0038] like Figure 6 As shown, the inertia ring 41 has multiple accommodating cavities arranged circumferentially, and each accommodating cavity contains a ball bearing 411. The ball bearing 411 can rotate within the corresponding accommodating cavity. On the one hand, with the same external dimensions, the ball bearing 411 can increase the local mass concentration and the equivalent rotation radius, further improving the rotational inertia of the energy storage structure 4; on the other hand, the rotatable arrangement of the ball bearing 411 within the accommodating cavity facilitates the smooth distribution of torque during start-up and shutdown, reduces the rigid impact between the inertia ring 41 and the mounting sleeve 42, thereby improving start-up and shutdown response and reducing noise.

[0039] like Figure 3 and Figure 6As shown, a bearing housing 44 for supporting the energy storage structure 4 is provided inside the pump casing 1. The bearing housing 44 includes a support arm 441 connected to the pump casing 1 and a bearing disposed on the support arm 441. The outer ring of the bearing is fixedly connected to the support arm 441, and the inner ring of the bearing is rotatably engaged with the mounting sleeve 42 to provide radial support for the second shaft section when the energy storage structure 4 rotates. By providing nearby support for the mounting sleeve 42 through the bearing housing 44, the additional burden of the mass of the energy storage structure 4 on the motor end support can be reduced, the rigidity and life of the overall shaft system can be improved, and the concentricity and stability during the free rotation stage after shutdown can be guaranteed. This makes the impeller 21 rotate more smoothly during the circulation stage after shutdown, reducing flow instability and noise fluctuations caused by vibration, further improving the bubble conveying effect and reducing the chance of bubble retention in local areas. At the same time, the improved rotational stability is also conducive to the stable sealing state of the sealing ring 5, reducing the potential impact of coolant leakage on the circuit board 25, and structurally enhancing the overall technical effect of the present invention.

[0040] like Figure 3 , Figure 5 As shown, a spline 221 is provided on the second rotating shaft section, and a spline sleeve 43 is provided inside the mounting sleeve 42. The spline sleeve 43 mates with the spline 221, enabling the energy storage structure 4 to reliably transmit torque to the second rotating shaft section in the circumferential direction and facilitating axial assembly and disassembly. The impeller 21 is installed at the end of the second rotating shaft section and is fixedly connected to the spline 221, so that when the energy storage structure 4 drives the second rotating shaft section to rotate, the impeller 21 rotates synchronously to maintain coolant circulation during shutdown. This arrangement allows the inertial energy storage to act directly on the impeller 21 without the need for additional intermediate transmission components, reducing energy loss and simplifying the structure.

[0041] like Figure 3 As shown, a first sealing ring 51 is provided between the mounting cavity 15 and the pump chamber in the pump housing 1, and a second sealing ring 52 is provided between the mounting cavity 15 and the electrical control housing. The first sealing ring 51 and the second sealing ring 52 are used to limit the leakage of coolant towards the motor assembly 2 and the circuit board 25. By arranging sealing rings at critical interfaces, the internal pressure and medium environment of the pump body can be kept stable during the shutdown and circulation process, preventing coolant from entering the electrical control housing due to pressure fluctuations caused by inertial rotation, thus ensuring the reliability of the motor and electronic components.

[0042] like Figure 6As shown, the sealing ring 5 can also be set at the corresponding mating part of the inertia ring 41 or in the mating area with the bearing to provide sealing protection for the area where the ball 411 is located, reduce the possibility of coolant or impurities entering the receiving cavity, and maintain the stability of the rotation environment of the ball 411. This makes the resistance of the energy storage structure 4 during the free rotation stage after shutdown smaller and more stable, which is beneficial to prolonging the circulation duration and improving the circulation effect. The more stable the circulation time, the more beneficial it is to cover the critical window of concentrated bubble generation during the short period of residual heat during shutdown, so that the bubbles are carried away by the flow before they form obvious accumulation, fundamentally weakening the conditions for bubble accumulation and further addressing the technical problem to be solved by the present invention.

[0043] Combination Figure 2 and Figure 3 The assembly method of this embodiment will be further described below. During assembly, the stator 24 can be fixedly installed in the mounting cavity 15 formed by the lower housing 12. The stator 24 and the mounting cavity 15 are radially positioned and circumferentially prevented from rotating through the positioning step and interference fit, so that the stator 24 remains stationary when the motor is working. Then, the rotor 23 is fixed on the first shaft section, so that the rotor 23 rotates synchronously with the first shaft section, and the second shaft section is installed into the pump housing 1 with one end extending into the pump cavity. Then, the energy storage structure 4 is assembled on the second shaft section, wherein the spline sleeve 43 is installed in the mounting sleeve 42 or forms an integral structure with the mounting sleeve 42, and then the spline sleeve 43 is engaged with the spline 221 on the second shaft section. The mounting sleeve 42 is fixed to the second shaft section in the circumferential direction and completes the axial positioning; the inertia ring 41 is fixed on the outer circumference of the mounting sleeve 42, and the ball bearing 411 is installed in the receiving cavity of the inertia ring 41 and sealed and protected by the sealing ring 5. The bearing housing 44 is then installed into the pump casing 1, the support arm 441 is fixedly connected to the pump casing 1, the outer ring of the bearing is fixedly connected to the support arm 441, and the inner ring of the bearing is rotatably engaged with the mounting sleeve 42, so that the energy storage structure 4 obtains radial support. The impeller 21 is then installed to the end of the second shaft section and fixedly connected with the spline 221. Then, an electromagnetic clutch assembly 3 is assembled between the first and second shaft sections, wherein the clutch mounting seat 36 is circumferentially fixedly connected to the first shaft section and rotates synchronously with it, the friction disc 35 is circumferentially fixedly connected to the second shaft section, the armature disc 33 is located on one side of the friction disc 35 and is limitedly engaged with the clutch mounting seat 36, allowing axial movement, and the reset member 34 applies an axial reset force to the armature disc 33. The fixed iron core 32 is fixedly installed on the pump casing 1, and the excitation coil 31 is sleeved on the outside of the fixed iron core 32 and electrically connected to the circuit board 25.

[0044] After assembling the aforementioned internal components, the circuit board 25 is installed in the electrical control housing. The circuit board 25 is electrically connected to the motor assembly 2 and the excitation coil 31, and the circuit board 25 is positioned and fixed by the structure of the electrical control housing. Subsequently, a first sealing ring 51 is installed between the mounting cavity 15 and the pump cavity, and a second sealing ring 52 is installed between the mounting cavity 15 and the electrical control housing, so that the sealing rings 51 and 52 are respectively located in their corresponding sealing grooves and form a circumferential compression. Finally, the upper housing 11 and the lower housing 12 are joined together, and the upper housing 11 and the lower housing 12 are fixedly connected by a connector 161 accommodated in the connecting groove 16. The clamping force of the connector 161 causes a stable compression between the housing connecting surface and the sealing rings 51 and 52, thereby ensuring the sealing reliability between the pump cavity and the areas of the motor assembly 2 and the circuit board 25. This assembly method is easy to implement in engineering, and the connection relationships are clear, ensuring the feasibility of the technical solution of this invention.

[0045] The following describes the specific implementation of this embodiment in conjunction with the working process. During normal vehicle operation, circuit board 25 drives motor assembly 2. Stator 24 generates a rotating magnetic field under the drive current output from circuit board 25, causing rotor 23 to rotate the first shaft section. Simultaneously, circuit board 25 energizes excitation coil 31. Armature disk 33, under the magnetic force generated by fixed iron core 32, attracts and presses against friction disk 35, allowing the torque of the first shaft section to be transmitted to the second shaft section via clutch mounting seat 36, armature disk 33, and friction disk 35. The second shaft section drives impeller 21 to rotate. Coolant enters the pump chamber through inlet 13, gains kinetic energy under the action of impeller 21, and is output from outlet 14, forming a forced circulation. During this stage, energy storage structure 4 rotates with the second shaft section and accumulates kinetic energy, essentially storing inertial capacity for circulation after shutdown. In addition, the ball bearing 411 rotates with the inertia ring 41, and the rotational engagement within the receiving cavity makes the force change of the inertia ring 41 smoother, reduces the sudden change in motor load, and helps to reduce the current fluctuation of the circuit board 25 during the driving process, thereby having a positive effect on the electrical reliability of the circuit board 25.

[0046] When the vehicle suddenly stops or the electric water pump loses power, the motor assembly 2 stops being driven by electricity, the excitation coil 31 is de-energized, the magnetic force of the fixed iron core 32 disappears, and the reset component 34 pulls the armature disk 33 away from the friction disk 35, causing the electromagnetic clutch assembly 3 to change from the engaged state to the released state, and the friction transmission link between the first and second shaft sections is released. Since the energy storage structure 4 is circumferentially fixedly connected to the second shaft section and the impeller 21, the energy storage structure 4 has already rotated with the second shaft section and has rotational inertia before the power is cut off. When the electromagnetic clutch assembly 3 is released, the braking effect that the electromagnetic braking on the rotor 23 side and the circuit related to the circuit of the circuit board 25 may produce no longer acts on the second shaft section and the energy storage structure 4 through the clutch path. The energy storage structure 4 can then continue to drive the second shaft section and the impeller 21 to rotate for a period of time under the action of inertia. Although the motor assembly 2 has stopped, the impeller 21 can still maintain a short-term pumping action, so that the coolant can still have a short-term circulating flow during the shutdown phase. This addresses the core problem that this invention aims to solve, namely, the problem of bubbles being generated in a short time during the shutdown residual heat phase but lacking flow, leading to accumulation.

[0047] During the residual heat phase after shutdown, high-temperature components such as the engine and exhaust side recirculate residual heat to the coolant. The vaporized and dissolved gases quickly concentrate into tiny bubbles. Because this invention maintains short-term circulation after shutdown, these tiny bubbles, once generated, are carried away from the vicinity of the hot spot and pump body by the flow, migrating along the cooling circuit to areas with relatively lower temperatures and larger volumes. After being carried away from the hot spot, the bubbles benefit from improved local heat exchange conditions, resulting in more thorough contact between the coolant and the metal wall near the hot spot, suppressing local temperature rise and further weakening the conditions for continued vaporization and bubble formation, thus ending the concentrated bubble formation phase more quickly. Furthermore, as the bubbles flow into a larger volume area, they disperse, no longer lingering and coalescing at the same local high point. As the residual heat release process gradually weakens, the driving factors for generating new bubbles within the system decrease, the bubble source ceases to be continuous, and the bubbles that were previously carried away and dispersed by the circulation lack the conditions to re-aggregate in the same local area. Specifically, the accelerated circulation has moved bubbles from areas prone to aggregation, such as localized high points and hot spots, to a longer flow path. The distribution of bubbles in the loop is sparser, and as the temperature gradually decreases after shutdown, some bubbles will redissolve in the coolant or shrink and dissipate in cooler areas. Even if a small number of residual bubbles remain, they are more likely to exist in a dispersed state in the loop, rather than continuously accumulating in the same localized location to form large-volume bubble piles. Therefore, this invention utilizes a short period of accelerated circulation after shutdown to cover the window of concentrated bubble formation, allowing bubbles to be carried away and dispersed before they are most likely to accumulate. This suppresses the risk of localized heat transfer attenuation and temperature surges caused by bubble accumulation during the residual heat phase of shutdown, and reduces the risk of flow instability and abnormal noise that may occur during subsequent restarts.

[0048] Furthermore, the electromagnetic clutch assembly 3 of this invention is in a released state after power is cut off, allowing the second shaft section, impeller 21, and energy storage structure 4 to rotate freely with reduced resistance, while the rotor 23 is isolated from the first shaft section. During the vehicle's shutdown phase, the cooling circuit may be affected by pressure pulsations, natural circulation, or backflow of the circuit liquid column, potentially causing the impeller 21 to rotate in the opposite direction. In conventional structures, this reverse rotation could cause the rotor 23 to reverse-cut the magnetic field and generate a back electromotive force at the motor end, thus adversely affecting the circuit board 25. This invention, by releasing the clutch, eliminates torque transmission between the first and second shaft sections. Even if the impeller 21 rotates in the opposite direction under the influence of external fluid, it is unlikely to cause the rotor 23 to rotate in the opposite direction synchronously, thereby reducing the risk of the back electromotive force affecting the circuit board 25. This anti-reverse rotation effect corresponds to the improved reliability of the circuit board 25, representing an additional technical effect of this invention that addresses the problem of bubble accumulation during the shutdown residual heat phase while also ensuring engineering reliability.

[0049] It should be noted that the connection methods in this embodiment can be adapted and adjusted according to specific engineering requirements. For example, the number of connectors 161 can be selected and evenly distributed according to the shell strength and sealing requirements to ensure that the connection surface between the upper shell 11 and the lower shell 12 is subjected to uniform force, thereby keeping the first sealing ring 51 and the second sealing ring 52 stably pressed; the fixed connection method between the clutch mounting seat 36 and the first rotating shaft section, and between the friction disc 35 and the second rotating shaft section can be selected according to the torque requirements to select interference fit or spline fit to ensure reliable torque transmission of the electromagnetic clutch assembly 3 in the engaged state; the fixing method between the inertia ring 41 and the mounting sleeve 42 can be selected according to space and process to select interference fit or fastening to ensure stable inertia contribution of the inertia ring 41; the connection between the support arm 441 of the bearing seat 44 and the pump shell 1 can be designed as an integral structure or a detachable structure to take into account both assembly convenience and support rigidity. The above adjustments do not change the core idea of ​​this invention, which is to release torque transmission through the electromagnetic clutch component 3 after shutdown and provide inertia to promote circulation through the energy storage structure 4. It can still achieve the technical effect of timely removing and suppressing the accumulation of bubbles generated in a short period of time during the shutdown residual heat stage.

[0050] In summary, this embodiment, by setting an electromagnetic clutch assembly 3 between the coaxially arranged first and second shaft sections and setting an energy storage structure 4 on the second shaft section, allows the electric water pump to release torque transmission and cut off the braking effect of the rotor 23 on the second shaft section and energy storage structure 4 after the motor assembly 2 stops or is powered off. This allows the energy storage structure 4 to continue driving the impeller 21 after stopping, promoting short-term circulation of coolant. This timely delivery and dispersion of bubbles during the short-term concentrated generation of bubbles due to residual heat reduces the chance of bubbles accumulating near local high points or hot spots. At the same time, the partitioned sealing of the first sealing ring 51, the second sealing ring 52, and the sealing ring 5 reduces the risk of coolant leakage to the circuit board 25 area, and the clutch release reduces the risk of reverse rotation affecting the circuit board 25. From an engineering perspective, this ensures the stable availability of the technical solution of this invention in a vehicle environment.

[0051] The above description is merely an embodiment of this application and is not intended to limit the scope of protection of this application. Any modifications, equivalent substitutions, or improvements made by those skilled in the art without departing from the spirit and principles of this invention should be included within the scope of protection of this application.

Claims

1. An electronic water pump that can promote circulation after shutdown, comprising a pump housing (1), a motor assembly (2) disposed within the pump housing (1), and an impeller (21), wherein the pump housing (1) has a pump chamber, a mounting cavity (15), and an inlet (13) and an outlet (14) communicating with the pump chamber, and the motor assembly (2) is disposed within the mounting cavity (15) and includes a stator (24) and a rotor (23), characterized in that: The rotor (23) is fixedly connected to a first shaft section, and a second shaft section is coaxially arranged on the first shaft section. One end of the second shaft section extends into the pump chamber and is connected to the impeller (21). An electromagnetic clutch assembly (3) is provided between the first shaft section and the second shaft section. An energy storage structure (4) is provided on the side of the electromagnetic clutch assembly (3) facing the impeller (21). The energy storage structure (4) includes a mounting sleeve (42) sleeved on the second shaft section and fixedly connected to it circumferentially, and an inertia ring (41) provided on the mounting sleeve (42). Structure (4) is supported in the pump housing (1) by bearing seat (44). The bearing on the bearing seat (44) is rotatably engaged with the mounting sleeve (42) to provide radial support for the second shaft section. The electromagnetic clutch assembly (3) transmits the torque between the first shaft section and the second shaft section when the motor assembly (2) is working. When the motor assembly (2) is stopped or de-energized, the torque transmission between the two is released and the two are allowed to rotate relative to each other, so that the energy storage structure (4) uses its own inertia to drive the second shaft section and the impeller (21) to continue to rotate.

2. The electronic water pump that can promote circulation after shutdown according to claim 1, characterized in that, The electromagnetic clutch assembly (3) includes an excitation coil (31), a fixed iron core (32), an armature disk (33), a reset component (34), a friction disk (35), and a clutch mounting base (36). The fixed iron core (32) is fixedly mounted on the pump casing (1). The excitation coil (31) is sleeved on the outside of the fixed iron core (32). The clutch mounting base (36) is circumferentially fixedly connected to the first rotating shaft section and rotates with the first rotating shaft section. The friction disk (35) is circumferentially fixedly connected to the second rotating shaft section and rotates integrally with the second rotating shaft section. The armature disk (33) is located on one side of the friction disk (35) and is allowed to move axially. The armature disk (33) and the clutch mounting seat (36) are in a circumferential upper limit engagement so that the armature disk (33) rotates synchronously with the clutch mounting seat (36). When the excitation coil (31) is energized, the armature disk (33) is attracted to the friction disk (35) and pressed against the friction disk (35), transmitting the torque of the first shaft segment to the second shaft segment through the clutch mounting seat (36), the armature disk (33) and the friction disk (35).

3. The electronic water pump that can promote circulation after shutdown according to claim 2, characterized in that, The reset member (34) is an elastic member, with one end connected to the pump housing (1) and the other end connected to the armature disk (33). The reset member (34) is used to apply an axial reset force to the armature disk (33) and allow the armature disk (33) to rotate with the clutch mounting seat (36). When the excitation coil (31) is de-energized, the armature disk (33) is pulled away from the friction disk (35) to release the torque transmission between the first shaft section and the second shaft section and allow the second shaft section to rotate freely relative to the first shaft section under inertia.

4. The electronic water pump that can promote circulation after shutdown according to claim 1, characterized in that, The energy storage structure (4) includes a mounting sleeve (42) sleeved on the second rotating shaft section and an inertia ring (41) fixed on the outer periphery of the mounting sleeve (42). The mounting sleeve (42) is fixedly connected to the second rotating shaft section in the circumferential direction, so that the inertia ring (41) rotates integrally with the second rotating shaft section to form rotational inertia energy storage.

5. The electronic water pump that can promote circulation after shutdown according to claim 4, characterized in that, The inertia ring (41) is provided with multiple accommodating cavities along the circumference, and each accommodating cavity is provided with a ball (411). The ball (411) can rotate in the corresponding accommodating cavity to increase the rotational inertia of the energy storage structure (4) while improving the torque fluctuation during the start-stop process.

6. The electronic water pump that can promote circulation after shutdown according to claim 5, characterized in that, The pump housing (1) is provided with a bearing seat (44) for supporting the energy storage structure (4). The bearing seat (44) includes a support arm (441) connected to the pump housing (1) and a bearing disposed on the support arm (441). The outer ring of the bearing is fixedly connected to the support arm (441), and the inner ring of the bearing is rotatably engaged with the mounting sleeve (42) to provide radial support for the second shaft section when the energy storage structure (4) rotates.

7. The electronic water pump that can promote circulation after shutdown according to claim 6, characterized in that, The second shaft section is provided with a spline (221), and the mounting sleeve (42) is provided with a spline sleeve (43). The spline sleeve (43) cooperates with the spline (221) so that the energy storage structure (4) and the second shaft section can reliably transmit torque in the circumferential direction and facilitate axial assembly and disassembly.

8. The electronic water pump that can promote circulation after shutdown according to claim 7, characterized in that, The impeller (21) is installed at the end of the second rotating shaft section and is fixedly connected to the spline (221) so that when the energy storage structure (4) drives the second rotating shaft section to rotate, the impeller (21) rotates synchronously to maintain the circulation of coolant during the shutdown phase.

9. The electronic water pump that can promote circulation after shutdown according to claim 1, characterized in that, The pump housing (1) forms an electrical control housing on the side away from the pump cavity. A circuit board (25) electrically connected to the motor assembly (2) is installed in the electrical control housing. A first sealing ring (51) is provided between the mounting cavity (15) and the pump cavity in the pump housing (1). A second sealing ring (52) is provided between the mounting cavity (15) and the electrical control housing. The first sealing ring (51) and the second sealing ring (52) are used to limit the leakage of coolant towards the motor assembly (2) and the circuit board (25).

10. The electronic water pump that can promote circulation after shutdown according to claim 9, characterized in that, The pump housing (1) is composed of an upper housing (11) and a lower housing (12). The upper housing (11) forms the liquid inlet (13), the liquid outlet (14) and the pump chamber. The lower housing (12) forms the mounting cavity (15) and the electrical control accommodating part. A connecting groove (16) is formed on the outer periphery of the lower housing (12). A connector (161) is contained in the connecting groove (16). The upper housing (11) is fixedly connected to the lower housing (12) through the connector (161).

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