Electric pump and assembling method of electric pump

Abstract

The electric pump comprises a rotor assembly, a pump shaft, a shaft limiting part and an isolation sleeve, the rotor assembly is located on the periphery of the pump shaft, the pump shaft is fixedly connected or connected with the shaft limiting part in a limiting mode, the shaft limiting part comprises a first welding part, and the isolation sleeve comprises a bottom. The bottom comprises a second welding part, the first welding part and the second welding part are welded and fixed, the bottom is provided with a first end face and a second end face, the first end face is close to the shaft limiting part relative to the second end face in the axial direction parallel to the electric pump, and the second end face is close to the shaft limiting part relative to the second end face. The area of the projection of the second welding part on the first end face is smaller than the area of the projection of the shaft limiting part on the first end face, and a distance exists between the second welding part and the second end face. The invention further discloses an assembling method of the electric pump. The method has the characteristic of reducing the leakage risk.

Description

[Technical field]

[0001] The present application relates to the field of vehicles, and in particular to components of a vehicle lubrication system and / or cooling system. [Background technology]

[0002] The electric pump includes an isolation sleeve, which is used to isolate the stator assembly and the rotor assembly to prevent the working medium from contacting the stator assembly when the electric pump is working. The electric pump also includes a shaft limiter, and the isolation sleeve is welded to the shaft limiter. Since the wall thickness of the isolation sleeve is relatively thin, if the welding energy is large, the isolation sleeve is easily damaged, which makes the electric pump have a risk of leakage. Therefore, how to reduce the risk of leakage is a technical problem. [Summary of the invention]

[0003] The purpose of the present application is to provide an electric pump that is conducive to reducing the risk of leakage.

[0004] To achieve the above purpose, one embodiment of the present application adopts the following technical solution:

[0005] An electric pump comprises a rotor assembly, a pump shaft, a shaft limiting portion and an isolation sleeve, wherein the rotor assembly is located at the outer periphery of the pump shaft, the pump shaft is fixedly connected or limitedly connected to the shaft limiting portion, the shaft limiting portion comprises a first welding portion, the isolation sleeve comprises a bottom portion, the bottom comprises a second welding portion, the first welding portion is welded and fixed to the second welding portion, the bottom comprises a first end face and a second end face, along a direction parallel to the axial direction of the electric pump, the first end face is close to the shaft limiting portion relative to the second end face, the area of ​​the projection of the second welding portion on the first end face is smaller than the area of ​​the projection of the shaft limiting portion on the first end face, and there is a spacing between the second welding portion and the second end face.

[0006] In the above technical solution, along the direction parallel to the axial direction of the electric pump, the area of ​​the projection of the second welding portion on the first end face is smaller than the area of ​​the projection of the shaft limiting portion on the first end face, and there is a spacing between the second welding portion and the second end face. When the isolation sleeve is fixedly connected to the shaft limiting portion, the contact area between the bottom and the shaft limiting portion is small, and the energy required for welding is small. Along the direction parallel to the axial direction of the electric pump, at least part of the bottom is not melted, so that at least part of the bottom is not damaged, which is beneficial to reduce the risk of leakage.

[0007] An embodiment of the present application further discloses the following technical solution: an assembly method of an electric pump, the assembly method of the electric pump comprising:

[0008] Obtain the shaft limiter and the isolation sleeve;

[0009] The shaft limiting part and the isolation sleeve are fixedly connected: a first welding part of the shaft limiting part and a second welding part of the isolation sleeve are fixed by welding, and during welding, a part of the bottom of the isolation sleeve is melted along a direction parallel to the axial direction of the electric pump.

[0010] In the above technical solution, when welding the first welding part of the fixed shaft limit part and the second welding part of the isolation sleeve, part of the bottom of the isolation sleeve is melted along the direction parallel to the axial direction of the electric pump, so that at least part of the bottom is not damaged, which is beneficial to reduce the risk of leakage.

Brief Description of the Drawings

[0011] Figure 1 is a schematic diagram of an electric pump according to an embodiment of the present application;

[0012] Figure 2 yes Figure 1 A schematic cross-sectional view of an electric pump shown;

[0013] Figure 3 yes Figure 2 A schematic diagram of the first viewing angle of the fixing of the middle isolation sleeve, the pump shaft and the shaft limiting part;

[0014] Figure 4 yes Figure 2 A schematic diagram of a second viewing angle showing the fixing of the middle isolation sleeve, the pump shaft and the shaft limiting portion;

[0015] Figure 5 yes Figure 4 A schematic diagram of the first embodiment of the section AA;

[0016] Figure 6 yes Figure 5 A magnified schematic diagram of part A;

[0017] Figure 7 yes Figure 5 A schematic diagram of a first viewing angle of the shaft limiting portion shown;

[0018] Figure 8 yes Figure 7 A cross-sectional schematic diagram of the shaft limiting portion shown;

[0019] Fig. 9 yes Figure 5 A schematic diagram of a first embodiment of the shaft limiting portion from one viewing angle;

[0020] Fig.10 yes Figure 5 A schematic diagram of a second embodiment of the shaft limiting portion from one viewing angle;

[0021] Fig.11 yes Figure 4 A schematic diagram of a second embodiment of section AA;

[0022] Fig.12 yes Fig.11 A magnified schematic diagram of part A;

[0023] Fig.13 yes Figure 4 Schematic diagram of the isolation sleeve;

[0024] Fig.14 yes Fig.13 A schematic diagram of a first embodiment of the isolation sleeve from one perspective;

[0025] Fig.15 yes Fig.13 A schematic diagram of a second embodiment of the isolation sleeve from one perspective is shown.

[0026] Figure numerals: 1, pump casing; 2, stator assembly; 3, isolation sleeve; 32, bottom; 321, first end face; 3211, first inner end face; 3212, first outer end face; 322, second end face; 30, isolation chamber; 4, rotor assembly; 41, permanent magnet; 42, impeller assembly; 5, pump shaft; 6, control assembly; 7, shaft limiter; 70, accommodating chamber; 71, fixing portion; 72, base; 721, third end face; 7211, third inner end face; 7212, third outer end face; 73, connecting portion; 8, welding portion; 81, first welding portion; 811, first welding protrusion; 82, second welding portion; 821, second welding protrusion; 10, first chamber; 20, second chamber. [Specific implementation method]

[0027] The present application is further described below with reference to the accompanying drawings and specific embodiments:

[0028] In order to enable those skilled in the art to better understand the technical solution of the present application, the present application is further described in detail below in conjunction with the accompanying drawings and specific implementation methods. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work. The directional words such as upper and lower involved in this article are defined by the positions of the parts shown in the drawings relative to each other, just for the clarity and convenience of expressing the technical solution. It should be understood that the directional words used in this article should not limit the scope of protection requested by this application.

[0029] The electric pump of the present application can be applied to a liquid circulation system. The electric pump can drive the liquid in the circulation system to flow. The fluid can be the lubricating oil of the lubrication system or the coolant of the cooling system. The present application takes the electric pump applied to the cooling circulation system as an example.

[0030] Please refer to Figures 1 to 15The electric pump includes a pump housing 1, a stator assembly 2, an isolation sleeve 3, a rotor assembly 4, a pump shaft 5 and a control assembly 6. The pump housing 1 can form a pump inner cavity, and the pump inner cavity includes a first cavity 10 and a second cavity 20. The first cavity 10 and the second cavity 20 are not connected. When the electric pump is working, a working medium flows through the first cavity 10, and the second cavity 20 is not directly in contact with the working medium. The rotor assembly 4 and at least part of the pump shaft 5 are located in the first cavity 10, at least part of the stator assembly 2 and at least part of the control assembly 6 are located in the second cavity 20, and the stator assembly 2 and the control assembly 6 are not in contact with the working medium to avoid short circuit. The rotor assembly 4 is sleeved on the outer periphery of the pump shaft 5, and the stator assembly 2 is electrically connected to the control assembly 6. The rotor assembly 4 includes a permanent magnet 41 and an impeller assembly 42. When the electric pump is working, the control assembly 6 controls the current of the stator assembly 2 and then controls the excitation magnetic field generated by the stator assembly 2. The rotor assembly 4 rotates around the pump shaft 5 or with the pump shaft 5 under the action of the excitation magnetic field.

[0031] Please refer to Figures 5 to 15 The electric pump also includes a shaft limiting portion 7, which is fixedly connected or limitedly connected to the pump shaft 5, and the shaft limiting portion 7 includes a first welding portion 81. The isolation sleeve 3 includes a bottom 32, and the bottom 32 includes a second welding portion 82. The first welding portion 81 is welded and fixed to the second welding portion 82. The bottom 32 has a first end face 321 and a second end face 322. Along the direction parallel to the axial direction of the electric pump, the first end face 321 is close to the shaft limiting portion 7 relative to the second end face 322. The area of ​​the projection of the second welding portion 82 on the first end face 321 is smaller than the area of ​​the projection of the shaft limiting portion 7 on the first end face 321, and there is a spacing between the second welding portion 82 and the second end face 322. When the isolation sleeve 3 is welded to the shaft limiting portion 7, the contact area between the bottom 32 and the shaft limiting portion 7 is small, the energy required for welding is small, and there is a spacing between the second welding portion 82 and the second end face 322 in a direction parallel to the axial direction of the electric pump, so that at least part of the bottom 32 is not melted, and thus at least part of the bottom 32 is not damaged, which is conducive to reducing the risk of leakage. In this embodiment, the projection of the second welding portion 82 on the first end face 321 overlaps with the projection of the shaft limiting portion 7 on the first end face 321, and the welding method of the shaft limiting portion 7 and the isolation sleeve 3 includes but is not limited to resistance welding, friction welding or hot melt welding. The electric pump includes a welding portion 8, and the shaft limiting portion 7 and the isolation sleeve 3 are fixedly connected by the welding portion 8. The welding portion 8 is a melt when the shaft limiting portion 7 and the isolation sleeve 3 are welded, and the welding portion 8 includes a first welding portion 81 and a second welding portion 82.

[0032] The shaft stopper 7 can be a stamping part or a machined part. Furthermore, the shaft stopper 7 is a thin-walled stamping part. The shaft stopper 7 has a relatively high production efficiency and a relatively low cost. The isolation sleeve 3 can be a stamping part or a machined part. Furthermore, the isolation sleeve 3 is a thin-walled stamping part. The isolation sleeve 3 has a relatively high production efficiency and a relatively low cost.

[0033] The material of the isolation sleeve 3 and the material of the shaft stopper 7 are the same material, for example, the isolation sleeve 3 and the shaft stopper 7 are both made of metal. Further, the material of the isolation sleeve 3 and the material of the shaft stopper 7 are both stainless steel, which has a high hardness and is not easy to rust after long-term contact with the working medium (such as water). It can effectively protect the parts installed in the isolation chamber 30 and will not affect the water quality. In addition, it will not crack or age after long-term use and has a high pressure-bearing strength.

[0034] In one embodiment, please refer to Figures 5 to 10 The shaft limiting portion 7 has a third end face 721, the extension direction of the first end face 321 is parallel to the extension direction of the third end face 721, the first welding portion 81 extends from the third end face 721 in a direction away from the shaft limiting portion 7, and the first welding portion 8 does not extend to the second end face 322. When the isolation sleeve 3 is welded to the shaft limiting portion 7, along a direction parallel to the axial direction of the electric pump, at least part of the bottom 32 is not melted, so that at least part of the bottom 32 is not damaged, which is beneficial to reduce the risk of leakage.

[0035] Along the direction parallel to the axial direction of the electric pump, the first welding portion 81 has a first distance, the distance from the first end face 321 to the second end face 322 is a second distance, and the ratio of the first distance to the second distance is 0.6 to 2. If the ratio of the first distance to the second distance is greater than 2, since a large amount of energy is required to melt the first welding portion 81, the isolation sleeve 3 may be punctured when the isolation sleeve 3 is welded to the shaft limiting portion 7, so that there is a risk of leakage of the isolation sleeve 3; if the ratio of the first distance to the second distance is less than 0.6, since a small amount of energy can melt the first welding portion 81, the fixing strength between the shaft limiting portion 7 and the isolation sleeve 3 may be weak, and the reinforcing effect on the bottom 32 of the isolation sleeve 3 after the isolation sleeve 3 is welded to the shaft limiting portion 7 is weak, and the isolation sleeve 3 is easily deformed by force. In the radial direction of the electric pump, the width of the first welding portion 81 is 0.5 mm to 2 mm. When the shaft limiting portion 7 is welded to the isolation sleeve 3, the first welding portion 81 and the first end face 321 can have a better contact area, thereby making the connection strength between the shaft limiting portion 7 and the isolation sleeve 3 higher.

[0036] In one embodiment, please refer to Figure 5 , Fig. 9 and Fig.10, along the direction parallel to the axial direction of the electric pump, the area of ​​the projection of the first welding portion 81 on the third end face 721 is smaller than the area of ​​the third end face 721, the first welding portion 81 includes a plurality of first welding protrusions 811, the first welding protrusions 811 protrude from the third end face 721 in a direction away from the shaft limiting portion 7, the projection of the first welding protrusions 811 on the third end face 721 is circular or polygonal, or the connecting line of the projections of the first welding protrusions 811 on the third end face 721 is circular or polygonal, when the isolation sleeve 3 is welded to the shaft limiting portion 7, the energy can be concentrated on the first welding protrusions 811, and a smaller energy can be used to weld the isolation sleeve 3 to the shaft limiting portion 7. In addition, the welding time is short and the production efficiency is high; furthermore, the connection strength between the isolation sleeve 3 and the shaft limiting portion 7 is relatively high; in other embodiments, the projection of the first welding portion 81 on the third end face 721 is circular or polygonal. In one embodiment, the third end face 721 includes a third inner end face 7211 and a third outer end face 7212, and the first welding portion 81 extends from the third end face 721 in a direction away from the shaft limiting portion 7. Along the radial direction of the shaft limiting portion 7, the third outer end face 7212 is located radially outside the third inner end face 7211, and the first welding portion 81 is located between the third inner end face 7211 and the third outer end face 7212. The projected area of ​​the first welding portion 81 on the third end face 721 is smaller than the area of ​​the third outer end face 7212. When the isolation sleeve 3 is welded to the shaft limiting portion 7, energy can be concentrated on the first welding portion 81, and the fixing strength of the isolation sleeve 3 and the shaft limiting portion 7 is relatively high. In addition, compared with the welding of the third end face 721 and the first end face 321, the energy requirement is relatively small. In the direction parallel to the axial direction of the electric pump, the area of ​​the projection of the first welding portion 81 on the first end face 321 is smaller than the area of ​​the first end face 321. Such a setting can fully ensure that there is a large contact area between the first welding portion 81 and the first end face 321, which is conducive to improving the welding strength. Alternatively, the area of ​​the first end face 321 of the bottom 32 is defined as the first area, and the area of ​​the projection of the first welding portion 81 on the first end face 321 is defined as the second area, and the first area is greater than the second area. Such a setting can fully ensure that there is a large contact area between the first welding portion 81 and the first end face 321, which is conducive to improving the welding strength.

[0037] In one embodiment, please refer to Figures 11 to 15 The shaft stopper 7 has a third end face 721, the extension direction of the first end face 321 is parallel to the extension direction of the third end face 721, and the second welding portion 82 extends from the first end face 321 in a direction away from the second end face 322. When the isolation sleeve 3 is welded to the shaft stopper 7, at least part of the bottom 32 is not melted in a direction parallel to the axial direction of the electric pump, so that at least part of the bottom 32 is not damaged, which is conducive to reducing the risk of leakage.

[0038] The shaft limiting portion 7 includes a base 72, and the base 72 has a third end face 721. Along the direction parallel to the axial direction of the electric pump, the thickness of the second welding portion 82 is less than the thickness of the base 72. Furthermore, along the direction parallel to the axial direction of the electric pump, the thickness of the second welding portion 82 is 0.3 to 0.7 times the thickness of the base 72. On the one hand, it is beneficial to have a strong connection strength between the shaft limiting portion 7 and the isolation sleeve 3; on the other hand, when the isolation sleeve 3 is welded to the shaft limiting portion 7, the energy demand is moderate, which is beneficial to energy saving.

[0039] In one embodiment, please refer to Fig.11 , Fig.14 and Fig.15 , along the direction parallel to the axial direction of the electric pump, the projection area of ​​the second welding portion 82 on the first end face 321 is smaller than the area of ​​the first end face 321, the second welding portion 82 includes a plurality of second welding protrusions 821, the second welding protrusions 821 protrude from the first end face 321 away from the bottom 32, and the projection of the second welding protrusions 821 on the first end face 321 is circular or polygonal; or the connecting line of the projection of the second welding protrusions 821 on the first end face 321 is circular or polygonal, when the isolation sleeve 3 is welded to the shaft limiting portion 7, the energy can be concentrated on the second welding protrusions 821, and a smaller energy can be used to weld the isolation sleeve 3 to the shaft limiting portion 7. In addition, the welding time is short and the production efficiency is high; furthermore, the connection strength between the isolation sleeve 3 and the shaft limiting portion 7 is relatively high; in other embodiments, the projection of the second welding portion 82 on the first end face 321 is circular or polygonal. In one embodiment, please refer to Fig.15 The first end face 321 includes a first inner end face 3211 and a first outer end face 3212, and the second welding portion 82 extends from the first end face 321 in a direction away from the shaft limiting portion 7. In the radial direction of the shaft limiting portion 7, the first outer end face 3212 is located radially outward of the first inner end face 3211, and the second welding portion 82 is located between the first inner end face 3211 and the first outer end face 3212. The projection area of ​​the second welding portion 82 on the first end face 321 is smaller than the area of ​​the first outer end face 3212. When the isolation sleeve 3 is welded to the shaft limiting portion 7, energy can be concentrated on the second welding portion 82, and the fixing strength of the isolation sleeve 3 and the shaft limiting portion 7 is relatively high. In addition, compared with the welding of the third end face 721 and the first end face 321, the energy requirement is relatively small. In the direction parallel to the axial direction of the electric pump, the area of ​​the projection of the second welding portion 82 on the third end face 721 is smaller than the area of ​​the third end face 721. Such a setting can fully ensure that there is a large contact area between the second welding portion 82 and the third end face 721, which is conducive to improving the welding strength. Alternatively, the area of ​​the third end face 721 of the shaft limiting portion 7 is defined as the first area, and the area of ​​the projection of the second welding portion 82 on the third end face 721 is defined as the second area, and the first area is greater than the second area. Such a setting can fully ensure that there is a large contact area between the second welding portion 82 and the third end face 721, which is conducive to improving the welding strength.

[0040] Please refer to Figures 2 to 15 , the shaft stopper 7 covers part of the first end face 321, the shaft stopper 7 has a base 72, the base 72 has a third end face 721, along the direction parallel to the axial direction of the electric pump, the thickness of the isolation sleeve 3 is less than the thickness of the base 72, further, the thickness of the bottom 32 is less than the thickness of the base 72, because along the direction parallel to the axial direction of the electric pump, the bottom 32 is close to the control component 6 relative to the base 72, the heat generated by the control component 6 is transferred to the bottom 32, because the thickness of the bottom 32 is relatively thin, the heat conduction rate is relatively high, the heat can be quickly transferred to the shaft stopper 7, and the outer surface of the shaft stopper 7 is in contact with the working medium, which is conducive to improving the heat dissipation effect of the electric pump. For example, when the material of the bottom 32 and the base 72 are both the same stainless steel, the bottom 32 is thinner, the thermal conductivity of the bottom 32 is relatively high, the bottom 32 can quickly transfer heat to the shaft stopper 7 (or base 72), and the outer surface and at least part of the inner surface of the shaft stopper 7 can be in contact with the working medium, which is conducive to improving the heat dissipation effect of the electric pump. In the radial direction of the electric pump, the width of the bottom 32 (or the first end face 321) is defined as the first width W1, and the maximum width of the shaft stopper 7 is the second width W2, the first width is greater than the second width; further, the second width is 0.5 to 0.9 times the first width, for example, the first width is 30 mm, and the second width ranges from 15 mm to 27 mm; further, the second width is 0.6 to 0.8 times the first width. The bottom 32 and the shaft stopper 7 can have a larger contact area, which is beneficial to improving the connection strength between the shaft stopper 7 and the isolation sleeve 3. After the shaft stopper 7 is fixed to the isolation sleeve 3, it is equivalent to increasing the thickness of part of the bottom 32, which is beneficial to increasing the deformation resistance of the bottom 32 of the isolation sleeve 3, and the isolation sleeve 3 is not easily deformed by force.

[0041] In this embodiment, please refer to Figures 5 to 15 The shaft limiting portion 7 includes a fixing portion 71, a connecting portion 73 and a base 72. The connecting portion 73 is connected to the fixing portion 71, and the connecting portion 73 is connected to the base 72. The fixing portion 71 is fixedly connected or limitedly connected to the pump shaft 5. The base 72 is welded and fixed to the isolation sleeve 3. The base 72 extends from the connecting portion 73 in a direction away from the pump shaft 5, so that the shaft limiting portion 7 and the isolation sleeve 3 have a larger contact area. After the shaft limiting portion 7 is fixed to the isolation sleeve 3, it is equivalent to increasing the thickness of part of the bottom 32, which is beneficial to increase the deformation resistance of the bottom 32 of the isolation sleeve 3, so that the isolation sleeve 3 is not easily deformed by force.

[0042] An assembling method of an electric pump, the assembling method of the electric pump comprising:

[0043] Obtain the shaft limiting portion 7 and the isolation sleeve 3;

[0044] Prepare the welding part 8: weld and fix the shaft stopper 7 and the isolation sleeve 3, specifically, fix and connect the shaft stopper 7 and the isolation sleeve 3: weld and fix the first welding part 81 of the shaft stopper 7 and the second welding part 82 of the isolation sleeve 3. During welding, part of the bottom 32 of the isolation sleeve 3 is melted in a direction parallel to the axial direction of the electric pump, so that at least part of the bottom 32 is not damaged, which is conducive to reducing the risk of leakage.

[0045] The assembly method of the electric pump includes: obtaining the pump shaft 5, fixedly connecting or limiting the connection between the pump shaft 5 and the shaft limiting portion 7, and fixing or limiting the connection between the pump shaft 5 and the shaft limiting portion 7 so that the concentricity of the pump shaft 5 and the shaft limiting portion 7 is higher. When the electric pump is working, the vibration amplitude of the pump shaft 5 is smaller and the noise is smaller.

[0046] In one embodiment, when preparing the welding portion 8, or when fixing the shaft stopper 7 and the isolation sleeve 3, a first welding electrode and a second welding electrode are provided, so that the first welding electrode contacts the isolation sleeve 3, and the second welding electrode contacts the pump shaft 5, and current is transmitted between the first welding electrode and the second welding electrode. One of the isolation sleeve 3 and the pump shaft 5 is connected to the positive electrode, and the other is connected to the negative electrode. After power is turned on, the first welding portion and the second welding portion are melted to achieve a fixed connection between the isolation sleeve 3 and the shaft stopper 7. In addition, since the welding is performed from the inside of the isolation sleeve 3, at least part of the isolation sleeve 3 is not damaged, and the leakage risk of the isolation sleeve 3 is relatively low.

[0047] Please refer to Figure 5 and Fig.11In the axial direction of the electric pump, a gap is set between the pump shaft 5 and the bottom wall (or the first end face 321) of the isolation sleeve 3, that is, the pump shaft 5 does not contact the first end face 321 of the isolation sleeve 3, or there is a certain distance between the pump shaft 5 and the first end face 321 of the isolation sleeve 3. For example, when resistance welding is used to connect the isolation sleeve 3 and the pump shaft stopper 7, if the pump shaft 5 contacts the isolation sleeve 3, the current will flow directly from the pump shaft 5 to the isolation sleeve 3, affecting the fixing effect between the isolation sleeve 3 and the shaft stopper 7. In some embodiments, the shaft stopper 7 has a receiving chamber 70, and the receiving chamber 70 is connected to the isolation chamber 30. When the electric pump is working, there is a working medium in the receiving chamber 70, and at least part of the pump shaft 5 is located in the receiving chamber 70. In the axial direction of the electric pump, the distance between the pump shaft 5 and the first end face 321 of the isolation sleeve 3 ranges from 0.2 mm to 2 mm, which ensures the fixing effect of the isolation sleeve 3 and the shaft stopper 7 while allowing the pump shaft 5 to have a larger contact area with the working medium. Of course, in other embodiments, the spacing between the pump shaft 5 and the first end surface 321 of the isolation sleeve 3 is in the range of 0.2 mm to 1 mm, which ensures that the isolation sleeve 3 and the shaft stopper 7 have a fixed effect, while allowing the pump shaft 5 to have a larger contact area with the working medium. Further, the spacing between the pump shaft 5 and the first end surface 321 of the isolation sleeve 3 is in the range of 0.5 mm to 1 mm. While ensuring that the isolation sleeve 3 and the shaft stopper 7 have a fixed effect, the pump shaft 5 and the working medium have a larger contact area.

[0048] It should be noted that the above embodiments are only used to illustrate the present application and are not intended to limit the technical solutions described in the present application. Although the present application has been described in detail in this specification with reference to the above embodiments, a person of ordinary skill in the art should understand that a person of ordinary skill in the art can still modify or make equivalent substitutions to the present application, and all technical solutions and improvements thereof that do not depart from the spirit and scope of the present application should be included in the scope of the claims of the present application.

Claims

1. An electric pump, characterized in that: The electric pump comprises a rotor assembly (4), a pump shaft (5), a shaft stopper (7) and a spacer sleeve (3); the rotor assembly (4) is located on the outer periphery of the pump shaft (5); the pump shaft (5) is fixedly connected or limit-connected to the shaft stopper (7); the shaft stopper (7) comprises a first welding portion (81); the spacer sleeve (3) comprises a bottom portion (32); the bottom portion (32) comprises a second welding portion (82); the first welding portion (81) and the second welding portion (82) are fixedly welded; The bottom (32) has a first end face (321) and a second end face (322); along a direction parallel to the axial direction of the electric pump, the first end face (321) is closer to the shaft limiting portion (7) relative to the second end face (322); the area of ​​the projection of the second welding portion (82) on the first end face (321) is smaller than the area of ​​the projection of the shaft limiting portion (7) on the first end face (321); and there is a spacing between the second welding portion (82) and the second end face (322).

2. The electric pump according to claim 1, characterized in that: The shaft limiting portion (7) has a third end face (721), the extension direction of the first end face (321) is parallel to the extension direction of the third end face (721), the first welding portion (81) extends from the third end face (721) in a direction away from the shaft limiting portion (7), and along a direction parallel to the axial direction of the electric pump, the area of ​​the projection of the first welding portion (81) on the third end face (721) is smaller than the area of ​​the third end face (721).

3. The electric pump according to claim 2, characterized in that: Along a direction parallel to the axial direction of the electric pump, the first welding portion (81) has a first distance, the distance from the first end surface (321) to the second end surface (322) is a second distance, and the ratio of the first distance to the second distance is 0.6-2.

4. The electric pump according to any one of claims 2 to 3, characterized in that: The first welding portion (81) comprises a plurality of first welding protrusions (811), and the projection of the first welding protrusions (811) on the third end surface (721) is circular or polygonal; or a line connecting the projections of the first welding protrusions (811) on the third end surface (721) is a circle or a polygon; Alternatively, the projection of the first welding portion (81) on the third end surface (721) is circular or polygonal.

5. The electric pump according to claim 1, characterized in that: The second welding portion (82) extends from the first end surface (321) in a direction away from the second end surface (322), and along a direction parallel to the axial direction of the electric pump, the projection area of ​​the second welding portion (82) on the first end surface (321) is smaller than the area of ​​the first end surface (321).

6. The electric pump according to claim 5, characterized in that The shaft limiting portion (7) comprises a base (72), the base (72) having a third end face (721), the extension direction of the third end face (721) being parallel to the extension direction of the first end face (321), and the thickness of the second welding portion (82) is smaller than the thickness of the base (72) along a direction parallel to the axial direction of the electric pump.

7. The electric pump according to any one of claims 5 to 6, characterized in that: The second welding portion (82) comprises a plurality of second welding protrusions (821), and the projection of the second welding protrusions (821) on the first end surface (321) is circular or polygonal; Or the second welding protrusion (821) is a circle or a polygon after connecting the projections of the first end surface (321); Alternatively, the projection of the second welding portion (82) on the first end surface (321) is circular or polygonal.

8. The electric pump according to any one of claims 1 to 7, characterized in that: The shaft limiting portion (7) covers a portion of the first end surface (321), and the shaft limiting portion (7) comprises a base (72). The base (72) is fixedly connected to the bottom (32), and the thickness of the bottom (32) is smaller than the thickness of the base (72).

9. A method for assembling an electric pump, characterized in that: The assembly method of the electric pump comprises: Obtaining the shaft limiting portion (7) and the isolation sleeve (3); The shaft limiting portion (7) and the isolation sleeve (3) are fixedly connected: a first welding portion (81) of the shaft limiting portion (7) and a second welding portion (82) of the isolation sleeve (3) are fixedly welded, and during welding, a portion of the bottom portion (32) of the isolation sleeve (3) is melted in a direction parallel to the axial direction of the electric pump.

10. The assembly method according to claim 9, characterized in that: A pump shaft (5) is obtained, and the pump shaft (5) and the shaft limiting portion (7) are fixedly connected or limit-connected; when the shaft limiting portion (7) and the isolation sleeve (3) are fixedly connected, a first welding electrode and a second welding electrode are provided, so that the first welding electrode contacts the isolation sleeve (3) and the second welding electrode contacts the pump shaft (5).

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