Rotor assembly, motor and booster pump

Abstract

The utility model discloses a rotor assembly, a motor and a booster pump, the rotor assembly comprises a support body and permanent magnets, the support body comprises a core part and tooth parts, the plurality of tooth parts are arranged around the core part, mounting grooves are arranged between the adjacent tooth parts, the plurality of permanent magnets are arranged in the plurality of mounting grooves in a one-to-one correspondence manner, and each permanent magnet comprises a first part and a second part, the second part is arranged on the side, away from the core part, of the first part, and the first part is gradually shrunk from the second part to the core part. The first part is gradually shrunk, so that the magnetic flux at the center of the rotor assembly can be reduced, the magnetic saturation phenomenon is avoided, the magnetic flux can more effectively pass through the rotor assembly and the stator assembly, the air gap flux density is improved, and the improvement of the air gap flux density is beneficial to improving the motor efficiency and reducing the motor volume.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of booster pumps, in particular to a rotor assembly, a motor and a booster pump. BACKGROUND

[0002] Some booster pump motors are brush motors, but the motor efficiency of brush motors is relatively low compared to brushless permanent magnet motors, and the size of brush motors is relatively large, which is not suitable for miniaturization and multifunctional development needs. The carbon brush of the brush motor is also prone to wear, which reduces the service life. In order to overcome the above problems, the booster pump in the related art adopts a brushless permanent magnet motor, but the rotor magnetic circuit topology of the brushless permanent magnet motor in the booster pump needs to be improved. SUMMARY

[0003] The present application aims to at least partially solve one of the technical problems in the related art. To this end, the present application proposes a rotor assembly.

[0004] To achieve the above-mentioned purpose, the present application discloses a rotor assembly, which comprises:

[0005] a support body comprising a core portion and a plurality of tooth portions, the plurality of tooth portions being arranged around the core portion, and an installation groove being arranged between adjacent tooth portions; and

[0006] a plurality of permanent magnets, each of the plurality of permanent magnets being arranged in one of the installation grooves, the permanent magnet comprising a first portion and a second portion, the second portion being arranged on a side of the first portion away from the core portion, the first portion being arranged taperedly from the second portion toward the core portion, one side of the permanent magnet being an N-pole and the other side being an S-pole, and the polarities of the facing sides of adjacent permanent magnets being the same.

[0007] In some embodiments of the present application, the second portion is parallel to both sides in the circumferential direction of the rotor assembly.

[0008] In some embodiments of the present application, in the circumferential direction of the rotor assembly, a midpoint between the two sides of the first portion is a first midpoint, and a midpoint between the two sides of the second portion is a second midpoint, a first virtual plane is defined, the first virtual plane passing through the first midpoint, the second midpoint and the rotation axis of the rotor assembly, and the first virtual plane constitutes a symmetry plane of the permanent magnet.

[0009] In some embodiments of the present application, a cross section of the first portion perpendicular to the rotation axis of the rotor assembly is a first cross section, the first cross section is a trapezoid, a cross section of the second portion perpendicular to the rotation axis of the rotor assembly is a second cross section, the second cross section is a rectangle, and a corner of a side of the second cross section away from the first portion constitutes a rounded corner.

[0010] In some embodiments of the application, the maximum length of the first portion along the radial direction of the rotor assembly is H2, and the maximum length of the permanent magnet along the radial direction of the rotor assembly is H1, satisfying 0.3≤H2 / H1≤0.5.

[0011] In some embodiments of the application, the minimum distance between the two sides of the first portion along the circumferential direction of the rotor assembly is L2, and the maximum distance between the two sides of the second portion along the circumferential direction of the rotor assembly is L1, satisfying 0.25≤L2 / L1≤0.55, 0.55≤L1 / L2≤0.7. R sin( ), θ= , P is the number of pole pairs of the rotor assembly, and R is the radius of the rotor assembly.

[0012] A second aspect of the application discloses an electric machine, comprising a stator assembly and the above-mentioned rotor assembly rotatably arranged inside the stator assembly.

[0013] In some embodiments of the application, the electric machine further comprises a housing and an end cover, the stator assembly is arranged in the housing, the end cover is connected to the housing, and the rotating shaft of the rotor assembly penetrates through the end cover.

[0014] In some embodiments of the application, the housing and the stator assembly are injection molded.

[0015] In some embodiments of the application, the housing is provided with a first mounting structure, and the electric machine is adapted to be connected to a target position through the first mounting structure.

[0016] In some embodiments of the application, the end cover is provided with a second mounting structure, and the electric machine is adapted to be connected to a target position through the second mounting structure.

[0017] A third aspect of the application discloses a booster pump, comprising a pump head and the above-mentioned electric machine, and the rotor assembly is adapted to act on the pump head to pump fluid.

[0018] Other advantages of the application will be given in part in the following description, part will become apparent from the following description, or will be understood by practicing the application. BRIEF DESCRIPTION OF DRAWINGS

[0019] ​​​In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the following will briefly introduce the drawings needed to be used in the embodiments or prior art description. Obviously, the drawings in the following description are only some embodiments of the present application, and for those skilled in the art, other drawings can also be obtained from the structures shown in the drawings without creative labor.

[0020] Figure 1 Schematic diagram of a booster pump in some embodiments;

[0021] Figure 2 Schematic diagram of a booster pump in some embodiments;

[0022] Figure 3 Schematic diagram of a booster pump in some embodiments (the section is different from that in Figure 2

[0023] Figure 4 Schematic diagram of a rotor assembly magnetic circuit topology in some embodiments;

[0024] Figure 5 Schematic diagram of a support body in some embodiments;

[0025] Figure 6 Schematic diagram of a permanent magnet in some embodiments;

[0026] Figure 7 Schematic diagram of a housing and stator assembly combination in some embodiments;

[0027] Figure 8 Schematic diagram of an end cover in some embodiments;

[0028] Figure 9 Air gap magnetic flux density diagram of a motor in some embodiments.

[0029] Explanation of the reference signs:

[0030] Booster pump 100, pump head 1000, motor 2000, rotor assembly 2100, support body 2110, core 2111, tooth portion 2112, mounting groove 2113, permanent magnet 2120, first portion 2121, second portion 2122, rotating shaft 2130, first virtual plane 2140, stator assembly 2200, housing 2300, first mounting structure 2310, end cover 2400, second mounting structure 2410.

[0031] The implementation, functional features and advantages of the present application will be further described with reference to the embodiments and the accompanying drawings. DETAILED DESCRIPTION

[0032] ​With reference to the drawings and the embodiments herein, the technical solutions in the embodiments will be described clearly and completely. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all the embodiments of the present application. Based on the embodiments herein, all the other embodiments obtained by a person of ordinary skill in the art without creative work fall within the protection scope of the present application.

[0033] It should be noted that all the direction indications (such as up, down, left, right, front, back, etc.) in the embodiments of the present application are only used to explain the relative position relationship, movement condition, etc. between components in a certain posture (as shown in the drawings), and if the certain posture changes, the direction indications also change accordingly.

[0034] In the present application, unless otherwise explicitly specified and limited, the terms “connection”, “fixation” and the like should be understood in a broad sense, for example, “fixation” can be fixed connection, or detachable connection, or integral; can be mechanical connection, or electrical connection; can be direct connection, or indirect connection through an intermediate medium; can be internal connection of two elements or interaction relationship between two elements, unless otherwise explicitly limited. For a person of ordinary skill in the art, the specific meaning of the above terms in the present application can be understood according to the specific circumstances.

[0035] In addition, the description such as “first”, “second” and the like in the present application is only for the purpose of description, and cannot be understood as indicating or implying the relative importance of the indicated technical features or implicitly indicating the number of the indicated technical features. Therefore, the features limited by “first”, “second” can explicitly or implicitly include at least one of the features. In addition, the technical solutions of each embodiment can be combined with each other, but it must be based on that a person of ordinary skill in the art can realize that when the combination of technical solutions appears contradictory or unachievable, it should be considered that the combination of technical solutions does not exist, and is not within the protection scope of the present application.

[0036] The first aspect of the present application discloses a rotor assembly 2100, which is combined with Figures 4 to 6As shown, in some embodiments, the rotor assembly 2100 includes a support body 2110 and permanent magnets 2120, the permanent magnets 2120 are installed on the support body 2110, the support body 2110 includes a core portion 2111 and tooth portions 2112, the number of the tooth portions 2112 is more than two, the tooth portions 2112 are arranged around the core portion 2111, and installation grooves 2113 are formed between adjacent tooth portions 2112, the number of the permanent magnets 2120 corresponds to the number of the installation grooves 2113, the permanent magnets 2120 are installed in the installation grooves 2113, the permanent magnets 2120 include first portions 2121 and second portions 2122, the second portions 2122 are arranged on the side of the first portions 2121 away from the core portion 2111, and the first portions 2121 are arranged tapered from the second portions 2122 to the core portion 2111. In this embodiment, by installing the permanent magnets 2120 in the installation grooves 2113, it is equivalent to embedding the permanent magnets 2120 in the support body 2110, and the first portions 2121 are designed to be tapered, when the rotor assembly 2100 is applied to the motor 2000 (or the motor 2000 includes the rotor assembly 2100), the air gap magnetic flux density can be effectively improved, thereby improving the efficiency of the motor 2000 and reducing the volume of the motor 2000.

[0037] The motor 2000 will be described in detail below, the rotor assembly 2100 is applied to the motor 2000, or the motor 2000 includes the rotor assembly 2100 and the stator assembly 2200, the rotor assembly 2100 is installed inside the stator assembly 2200, and the rotor assembly 2100 is designed to be rotatable, the stator assembly 2200 generates a changing magnetic field when energized, and the changing magnetic field and the rotor assembly 2100 interact to make the rotor assembly 2100 rotate.

[0038] The rotor assembly 2100 comprises a support body 2110, permanent magnets 2120 and a rotating shaft 2130. The support body 2110 is the framework of the rotor assembly 2100 and can support the permanent magnets 2120. The support body 2110 can be made of silicon steel sheets, and comprises a core part 2111 and tooth parts 2112. Generally, the core part 2111 and the tooth parts 2112 are integrally formed. The core part 2111 is substantially cylindrical, and the rotating shaft 2130 penetrates through the core part 2111 and is connected and fixed. The tooth parts 2112 are arranged on the core part 2111, and a plurality of tooth parts 2112 surround the core part 2111. The tooth parts 2112 can have various shapes, such as a fan shape. Adjacent tooth parts 2112 (referring to two adjacent tooth parts 2112) are provided with mounting grooves 2113. The permanent magnets 2120 are inserted into the mounting grooves 2113 and fixed in the mounting grooves 2113, so as to be assembled with the support body 2110. The permanent magnets 2120 can be made of rare earth permanent magnet material, ferrite permanent magnet material, aluminum-nickel-cobalt alloy, iron-chromium-cobalt alloy, etc.

[0039] The permanent magnets 2120 are mounted in the mounting grooves 2113, which is equivalent to an embedded arrangement, which is conducive to the compact design of the rotor assembly 2100. The combination of the permanent magnets 2120 and the support body 2110 also has high structural strength, which reduces the risk of the permanent magnets 2120 falling off, and is particularly suitable for high-speed operation applications. On this basis, the structure of the permanent magnets 2120 is further optimized. The permanent magnets 2120 comprise first parts 2121 and second parts 2122. The first parts 2121 and the second parts 2122 are arranged in sequence along a direction away from the center of the rotor assembly 2100, i.e., the first parts 2121 are arranged on a side of the second parts 2122 facing the center (core part 2111) of the rotor assembly 2100, and the second parts 2122 are arranged on a side of the first parts 2121 away from the center (core part 2111) of the rotor assembly 2100. The first parts 2121 are designed to gradually decrease towards the center (core part 2111) of the rotor assembly 2100 from the second parts 2122. By gradually decreasing the first parts 2121, the magnetic flux at the center of the rotor assembly 2100 can be reduced, magnetic saturation can be avoided, and the magnetic flux can pass through the rotor assembly 2100 and the stator assembly 2200 more effectively, thereby improving the air gap flux density. The improvement of the air gap flux density is conducive to improving the efficiency of the motor 2000 and reducing the size of the motor 2000.

[0040] Further, the rotor assembly 2100 is combined with the stator assembly 2200. Figures 4 to 6As shown, in some embodiments, the second part 2122 is arranged parallel to each other along the two sides of the circumferential direction of the rotor assembly 2100, and it can be understood that the second part 2122 is closer to the stator assembly 2200 than the first part 2121. By designing the second part 2122 parallel to each other along the two sides of the circumferential direction of the rotor assembly 2100, it is beneficial to strengthen the magnetic flux density at the position of the second part 2122, thereby further improving the air gap flux density, and in turn, it is beneficial to improve the efficiency of the motor 2000.

[0041] In combination Figure 4 As shown, in some embodiments, the midpoint between the two sides of the circumferential direction of the rotor assembly 2100 of the first part 2121 is defined as the first midpoint, the midpoint between the two sides of the circumferential direction of the rotor assembly 2100 of the second part 2122 is defined as the second midpoint, and the first virtual plane 2140 is defined, which passes through the rotation axis of the rotor assembly 2100, the first midpoint and the second midpoint, and the first virtual plane 2140 constitutes the symmetry plane of the permanent magnet 2120, that is, the permanent magnet 2120 is a symmetric structure about the first virtual plane 2140. The first virtual plane 2140 is an artificially defined plane, when the first virtual plane 2140 passes through the rotation axis of the rotor assembly 2100, the first virtual plane 2140 is a radial plane of the rotor assembly 2100, and the first virtual plane 2140 can pass through the first midpoint and the second midpoint at the same time. The first virtual plane 2140 divides the permanent magnet 2120 into two symmetrical halves. By such arrangement, the permanent magnet 2120 generates a more uniform magnetic field along the two sides of the circumferential direction of the rotor assembly 2100, thereby reducing torque fluctuation, which is beneficial to improve the efficiency of the motor 2000. Also, the reduction of torque fluctuation will also reduce the noise and vibration of the motor 2000 during operation.

[0042] For example Figure 4 And Figure 6The rotor assembly 2100 shown defines a first section 2121 as a first cross section perpendicular to the rotation axis of the rotor assembly 2100, the first cross section being trapezoidal, the lower base of the trapezoid being connected to the second section 2122, so that the first section 2121 is tapered from the second section 2122 towards the core 2111, when the permanent magnet 2120 is a symmetrical structure about the first virtual plane 2140, the first cross section is an isosceles trapezoid, by designing the first cross section as a trapezoid, it is convenient to form the tapered first section 2121, thereby improving the air gap magnetic flux density, and the trapezoidal first cross section is also convenient for processing the permanent magnet 2120. The second section 2122 is defined as a second cross section perpendicular to the rotation axis of the rotor assembly 2100, by designing the second cross section as a rectangle, thereby making the two sides of the second section 2122 along the circumferential direction of the rotor assembly 2100 parallel, thereby improving the air gap magnetic flux density and facilitating the processing of the permanent magnet 2120.

[0043] Further, the corner of the side of the second section 2122 away from the first section 2121 is a rounded corner, that is, the corner of the side of the second section 2122 away from the first section 2121 is a rounded corner, and the side of the second section 2122 away from the first section 2121 is close to the stator assembly 2200 relative to the first section 2121, and since the air gap magnetic flux density is improved by improving the rotor assembly 2100, the corner of the side of the second section 2122 away from the first section 2121 is designed as a rounded corner, which can reduce the local concentration of magnetic flux at the corner and improve the continuity of the magnetic circuit, which is more conducive to improving the efficiency of the motor 2000, in addition, at the outer edge of the permanent magnet 2120 (away from the center of the rotor assembly 2100), if there is a sharp corner, stress concentration will occur, which will cause material fatigue, and the rounded corner can reduce stress concentration and improve the mechanical strength and durability of the permanent magnet 2120.

[0044] In combination Figure 4 As shown, in some embodiments, the maximum length of the permanent magnet 2120 along the radial direction of the rotor assembly 2100 is H1, the maximum length of the first section 2121 along the radial direction of the rotor assembly 2100 is H2, the minimum distance between the two sides of the first section 2121 along the circumferential direction of the rotor assembly 2100 is L2, the maximum distance between the two sides of the second section 2122 along the circumferential direction of the rotor assembly 2100 is L1, and 0.55≤ ≤0.7, 0.25≤ ≤0.55, 0.3≤ ≤0.5, where L3=2 R sin( ), θ= R is a radius of the rotor assembly 2100, and P is a number of pole pairs of the rotor assembly 2100. For example L1 has a value of 0.5, 0.6 or 0.7, L2 has a value of 0.25, 0.35, 0.45 or 0.55, 0.3 L3 has a value of 0.3, 0.4 or 0.5, Figure 4 The number of pole pairs of the rotor assembly 2100 in L1, L2, L3, H1 and H2 is 10. Through a large number of tests of the inventor, by optimizing L1, L2, L3, H1 and H2, the air gap flux can be further improved, thereby further optimizing the efficiency of the motor 2000, and at the same time making the structure of the rotor assembly 2100 more compact, which is more conducive to the design of miniaturization.

[0045] As shown in Figure 4 In some embodiments, along the circumference of the rotor assembly 2100, one side of the permanent magnet 2120 is N-pole and the other side is S-pole, and the polarity of the opposite side of the adjacent permanent magnet 2120 is the same. Here, the polarity of the opposite side of the adjacent permanent magnet 2120 means that the polarity of one side of one of the adjacent permanent magnets 2120 facing the other and the polarity of one side of the other facing the former are the same. For example, three permanent magnets 2120 are first permanent magnet, second permanent magnet and third permanent magnet arranged around the core 2111 in turn, the side of the first permanent magnet facing the second permanent magnet is S-pole, the side of the second permanent magnet facing the first permanent magnet is S-pole, the side of the second permanent magnet facing the third permanent magnet is N-pole, and the side of the third permanent magnet facing the second permanent magnet is N-pole, and so on. Alternatively, the side of the first permanent magnet facing the second permanent magnet is N-pole, the side of the second permanent magnet facing the first permanent magnet is N-pole, the side of the second permanent magnet facing the third permanent magnet is S-pole, and the side of the third permanent magnet facing the second permanent magnet is S-pole. By setting the polarity of the opposite side of the adjacent permanent magnet 2120 to be the same, not only can the air gap flux be improved, but also the magnetic hysteresis loss can be reduced, further improving the efficiency of the motor 2000, and also helping to improve the overload capacity of the motor 2000.

[0046] The second aspect of the present application discloses a motor 2000, as shown in Figures 1 to 8 The motor 2000 comprises a rotor assembly 2100 and a stator assembly 2200. The rotor assembly 2100 is installed inside the stator assembly 2200 and is designed to be rotatably arranged. The stator assembly 2200 generates a changing magnetic field when energized. The changing magnetic field and the rotor assembly 2100 interact to make the rotor assembly 2100 rotate.

[0047] The rotor assembly 2100 comprises a support body 2110 and permanent magnets 2120, the permanent magnets 2120 are installed on the support body 2110, the support body 2110 comprises a core portion 2111 and tooth portions 2112, the number of the tooth portions 2112 is plural, which means two or more, the same below, the tooth portions 2112 are arranged around the core portion 2111, and installation grooves 2113 are formed between adjacent tooth portions 2112, the number of the permanent magnets 2120 corresponds to the number of the installation grooves 2113, the permanent magnets 2120 are installed in the installation grooves 2113, the permanent magnets 2120 comprise first portions 2121 and second portions 2122, the second portions 2122 are arranged on the side of the first portions 2121 away from the core portion 2111, and the first portions 2121 are arranged tapered from the second portions 2122 to the core portion 2111. In this embodiment, by installing the permanent magnets 2120 in the installation grooves 2113, it is equivalent to embedding the permanent magnets 2120 in the support body 2110, and the first portions 2121 are designed to be tapered, when the rotor assembly 2100 is applied to the motor 2000 (or the motor 2000 comprises the rotor assembly 2100), the air gap magnetic flux density can be effectively improved, thereby improving the efficiency of the motor 2000 and reducing the volume of the motor 2000. Figure 9 As shown in the air gap magnetic flux density diagram of the motor 2000, by improving the rotor assembly 2100, the air gap magnetic flux density can be effectively improved (in this embodiment, L1 of the rotor assembly 2100 is 7.5 mm, L2 is 4.75 mm, L3 is 16.06 mm, H1 is 16.24 mm, H2 is 6.33 mm, R is 26 mm, θ is 36°, and the number of pole pairs is 10). It can be understood that the rotor assembly 2100 of the motor 2000 of this embodiment adopts the technical solutions of the above-mentioned embodiments, and therefore at least has the beneficial effects brought by the technical solutions of the above-mentioned embodiments, which will not be repeated here.

[0048] In combination with Figures 1 to 3 and Figure 7 , Figure 9 As shown, in some embodiments, the motor 2000 comprises a housing 2300 and an end cover 2400, the stator assembly 2200 is arranged in the housing 2300, that is, the stator assembly 2200 and the housing 2300 are connected and fixed with each other, the end cover 2400 is connected with the housing 2300 to cover the rotor assembly 2100, and the rotating shaft 2130 of the rotor assembly 2100 needs to pass through the end cover 2400. Generally, the end cover 2400 and the housing 2300 are connected by screws, the stator assembly 2200 and the housing 2300 are combined together first, then the rotor assembly 2100 is installed in the inside of the stator assembly 2200, and then the end cover 2400 is connected to the housing 2300, so as to realize the wrapping protection of the stator assembly 2200 and the rotor assembly 2100.

[0049] It can be understood that the shell 2300 and the stator assembly 2200 are connected and fixed in various ways, for example, the shell 2300 is provided with a positioning structure, the stator assembly 2200 is mounted to the shell 2300 corresponding to the positioning structure, and then a screw or other means is used to realize the connection and fixation between the shell 2300 and the stator assembly 2200, but this way is slightly troublesome, and in the embodiment, the shell 2300 and the stator assembly 2200 are injection molded, that is, the shell 2300 is combined with the stator assembly 2200 during molding, which simplifies the connection and fixation structure of the shell 2300 and the stator assembly 2200, reduces the connection difficulty of the shell 2300 and the stator assembly 2200, and also effectively reduces the cost. For example, the stator assembly 2200 is placed in a mold, and plastic (such as BMC, bulk molding compound) is injected into the mold, the plastic is molded into the shell 2300, and the plastic is tightly combined with the stator assembly 2200 during molding.

[0050] In combination with Figure 1 , Figure 7 and Figure 9 shown, in some embodiments, the shell 2300 is provided with a first mounting structure 2310, through which the motor 2000 can be mounted to a target position, for example, the first mounting structure 2310 has a fastening hole, and the opposite sides of the shell 2300 are respectively provided with the first mounting structure 2310, and the motor 2000 is mounted by the screw passing through the fastening hole and connected to the target position. Further, the end cover 2400 is provided with a second mounting structure 2410, through which the motor 2000 can be mounted to a target position, since the first mounting structure 2310 is arranged on the shell 2300 and the second mounting structure 2410 is arranged on the end cover 2400, then the first mounting structure 2310 and the second mounting structure 2410 are arranged along the axial direction of the motor 2000, effectively realizing the connection and fixation effect of the motor 2000.

[0051] The third aspect of the present application discloses a booster pump 100, which comprises a pump head 1000 and the above-mentioned motor 2000. The motor 2000 cooperates with the pump head 1000 so as to act on the pump head 1000, so that the pump head 1000 realizes the pumping of fluid. The fluid can be gas or liquid. The motor 2000 of the booster pump 100 in the embodiment adopts the technical solutions of the above-mentioned embodiments, and thus at least has the beneficial effects brought by the technical solutions of the above-mentioned embodiments, which will not be repeated here. For example Figure 1 The booster pump 100 shown in the above-mentioned booster pump 100 is a diaphragm pump, and the pump head 1000 is mounted to the end cover 2400. The rotor assembly 2100 drives the diaphragm of the pump head 1000 to move, thereby realizing the pumping of liquid.

[0052] The above merely describes the preferred embodiments of the present application, and is not intended to limit the patent scope of the present application. Any equivalent structural changes made according to the content of the present application specification and drawings, or direct / indirect application in other related technical fields are included in the patent protection scope of the present application.

Claims

1. A rotor assembly (2100) characterized by, The motor (2000) further comprises a housing (2300) and an end cover (2400), the stator assembly (2200) is arranged in the housing (2300), the end cover (2400) is connected with the housing (2300), and the rotating shaft (2130) of the rotor assembly (2100) penetrates through the end cover (2400). The housing (2300) and the stator assembly (2200) are injection molded; And / or, the housing (2300) is provided with a first mounting structure (2310), and the motor (2000) is adapted to be connected to a target position through the first mounting structure (2310); 2. The rotor assembly (2100) of claim 1, wherein, And / or, the end cover (2400) is provided with a second mounting structure (2410), and the motor (2000) is adapted to be connected to a target position through the second mounting structure (2410).

3. The rotor assembly (2100) of claim 1, wherein, The second part (2122) is parallel to both sides along the circumferential direction of the rotor assembly (2100).

4. The rotor assembly (2100) of claim 1, wherein, A maximum length of the permanent magnet (2120) along a radial direction of the rotor assembly (2100) is H1, a maximum length of the first portion (2121) along the radial direction of the rotor assembly (2100) is H2, and 0.3≤H2 / H1≤0.5 is satisfied. ≤0.

5.

5. The rotor assembly (2100) of claim 1, wherein, The first portion (2121) has a minimum distance L2 between two sides of the circumference of the rotor assembly (2100), the second portion (2122) has a maximum distance L1 between two sides of the circumference of the rotor assembly (2100), satisfying 0.25≤ ≤0.55, 0.55≤ ≤0.7, where L3=2 R sin( ), θ= , P is the number of pole pairs of the rotor assembly (2100), and R is the radius of the rotor assembly (2100).

6. An electric machine (2000) characterized by, Along the circumferential direction of the rotor assembly (2100), the midpoint between the two sides of the first part (2121) is a first midpoint, the midpoint between the two sides of the second part (2122) is a second midpoint, a first virtual plane (2140) is defined, the first virtual plane (2140) passes through the first midpoint, the second midpoint and the rotating axis of the rotor assembly (2100), and the first virtual plane (2140) constitutes a symmetry plane of the permanent magnet (2120).

7. The electric machine (2000) of claim 6, wherein, The motor (2000) further comprises a housing (2300) and an end cover (2400), the stator assembly (2200) is arranged in the housing (2300), the end cover (2400) is connected with the housing (2300), and the rotating shaft (2130) of the rotor assembly (2100) penetrates through the end cover (2400).

8. The electric machine (2000) of claim 7, wherein, The housing (2300) and the stator assembly (2200) are injection molded; And / or, the housing (2300) is provided with a first mounting structure (2310), and the motor (2000) is adapted to be connected to a target position through the first mounting structure (2310); And / or, the end cover (2400) is provided with a second mounting structure (2410), and the motor (2000) is adapted to be connected to a target position through the second mounting structure (2410). The second part (2122) is parallel to both sides along the circumferential direction of the rotor assembly (2100). Along the circumferential direction of the rotor assembly (2100), the midpoint between the two sides of the first part (2121) is a first midpoint, the midpoint between the two sides of the second part (2122) is a second midpoint, a first virtual plane (2140) is defined, the first virtual plane (2140) passes through the first midpoint, the second midpoint and the rotating axis of the rotor assembly (2100), and the first virtual plane (2140) constitutes a symmetry plane of the permanent magnet (2120). The motor (2000) further comprises a housing (2300) and an end cover (2400), the stator assembly (2200) is arranged in the housing (2300), the end cover (2400) is connected with the housing (2300), and the rotating shaft (2130) of the rotor assembly (2100) penetrates through the end cover (2400). The housing (2300) and the stator assembly (2200) are injection molded; And / or, the housing (2300) is provided with a first mounting structure (2310), and the motor (2000) is adapted to be connected to a target position through the first mounting structure (2310); And / or, the end cover (2400) is provided with a second mounting structure (2410), and the motor (2000) is adapted to be connected to a target position through the second mounting structure (2410).

9. A booster pump (100) characterized by, A pump head (1000) and an electric machine (2000) according to any one of claims 6 to 8, said rotor assembly (2100) being adapted to act on said pump head (1000) to cause said pump head (1000) to pump fluid.

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