Rotor assembly, motor and electronic pump

Abstract

The utility model provides a rotor assembly, a motor and an electronic pump, the rotor assembly comprises a rotor magnet and a rotor core, and the rotor assembly is formed by superposing a plurality of silicon steel sheets along the axial direction; each silicon steel sheet comprises a main body with a regular polygonal section and a plurality of clamping jaw structures; each clamping jaw structure is located at one vertex of the regular polygon and comprises two clamping jaws, and the two clamping jaws are symmetrical about an axis passing through the vertex where the clamping jaw structure is located and the center of the regular polygon; every two adjacent silicon steel sheets are stacked in a staggered mode, so that a plurality of clamping jaw structure rows are formed, each clamping jaw structure row defines two clamping jaw rows, and one clamping jaw row and the adjacent clamping jaw row in the adjacent clamping jaw structure row jointly define a containing groove for containing a rotor magnet. By adopting the rotor assembly provided by the utility model, an expensive retainer is omitted, the cost is greatly reduced, the performance loss of the magnets is reduced, the problem that the magnets fall off in the transfer process is avoided, and the reliability of products is improved.

Description

Technical Field

[0001] The utility model relates to the technical field of motors, in particular to a rotor assembly and a motor and an electronic pump comprising the rotor assembly. Background Art

[0002] In brushless motors, rotors with surface-mounted magnets are often used. These surface-mounted magnets can be retained by a retaining frame on the outer circumference of a rotor core, for example, which is made of stacked silicon steel sheets. The rotor core, magnets, and retaining frame are then injection-molded together and fixed.

[0003] As in the technical solutions known in the prior art, a plastic retainer is usually provided to retain the magnet in the radial direction between the plastic retainer and the outer peripheral surface of the rotor core. However, in this technical solution, the mold cost of the retainer is relatively high and it is not easy to assemble. Moreover, since the magnet needs to be inserted between the silicon steel sheet and the plastic retainer, a certain gap is often required between the plastic retainer and the silicon steel sheet. A large gap may cause the magnet to loosen after assembly, resulting in the problem of the magnet position slipping or even falling off during transportation to the injection molding machine. In addition, due to the existence of the gap, the magnetic gap between the magnet and the silicon steel sheet becomes larger, resulting in increased magnetic resistance and reduced magnetic properties. If the gap is designed to be too small, it will cause the magnet to be difficult to insert or unable to be inserted, and the magnet surface will be severely scratched. For this reason, it is necessary to propose an improved fixing structure for rotor magnets. Utility Model Content

[0004] The purpose of the present invention is to solve at least one of the above problems and / or other problems existing in the prior art.

[0005] To achieve the above-mentioned purpose, according to the first aspect of the utility model, it provides a rotor assembly, which includes a rotor magnet and a rotor core, wherein the rotor core is formed by stacking a plurality of silicon steel sheets in an axial direction, each silicon steel sheet including a main body with a regular polygonal cross-section and a plurality of claw structures protruding radially outward from the main body; the number of the rotor magnets is equal to the number of sides of the regular polygon; wherein each claw structure is located at a vertex of the regular polygon and each claw structure includes two claws, and the two claws are symmetrical about an axis passing through the vertex where the claw structure is located and the center of the regular polygon; wherein every two adjacent silicon steel sheets are stacked in an offset manner at the same angle and in the same direction, so that a plurality of claw structure columns spaced from each other are formed along the circumferential direction of the rotor core, and each claw structure column includes two claw columns; wherein a claw column in each claw structure column and one of the adjacent claw columns in the adjacent claw structure column jointly define an accommodating groove for receiving the rotor magnet therein.

[0006] According to one embodiment of the utility model, each claw includes a guide section in the form of a ramp and a clamping section in the form of a straight line, and the claw is designed so that when the rotor magnet is radially inserted into the accommodating slot, the guide sections in the two adjacent claw rows defining the accommodating slot provide guidance and the rotor magnet is pressed against the outer peripheral wall of the rotor core with a pre-tightening force by the clamping section.

[0007] According to one embodiment of the utility model, each silicon steel sheet includes a plurality of claw structure groups arranged at intervals along the circumferential direction, so that the silicon steel sheet has a rotationally symmetrical structure, wherein each claw structure group includes at least two claw structures, and the at least two claw structures are respectively arranged at a corresponding number of adjacent vertices, wherein the angle between each two adjacent silicon steel sheets at which they are offset and overlapped is determined by the following formula: α=m×360° / n, wherein α is the angle, n is the number of rotor magnets, and m is the number of claw structures included in each claw structure group.

[0008] According to one embodiment of the present utility model, the number of the rotor magnets is ten, the number of the claw structures included in each claw structure group is two, and the misalignment angle between every two adjacent silicon steel sheets is 72°.

[0009] According to one embodiment of the utility model, the multiple claw structures of each silicon steel sheet are arranged at equal angular intervals in the circumferential direction, so that the silicon steel sheet has a rotationally symmetrical structure, wherein the angle between each two adjacent silicon steel sheets that are offset and overlapped with each other is determined by the following formula: α=360° / n, wherein α is the angle and n is the number of rotor magnets.

[0010] According to an embodiment of the present invention, each silicon steel sheet is provided with a central through hole and a plurality of positioning structures are provided at intervals along the circumference of the central through hole to facilitate positioning of the rotor magnet for magnetizing the rotor magnet.

[0011] According to one embodiment of the present utility model, the central through hole includes a through hole body and a positioning notch protruding radially outward from the through hole body and having a semicircular cross-section, and the positioning notch serves as the positioning structure.

[0012] According to an embodiment of the present invention, the rotor core and the rotor magnet are molded into an integral part by plastic overmolding.

[0013] According to a second aspect of the utility model, a motor is also provided, comprising the rotor assembly as described above.

[0014] According to a third aspect of the utility model, an electronic pump is also provided. The electronic pump comprises the motor as described above.

[0015] By adopting the improved rotor assembly according to the utility model, at least one of the following beneficial technical effects can be achieved: the expensive plastic retaining frame and the expensive injection mold are eliminated, thereby greatly reducing the cost; by keeping the rotor magnet tightly against the rotor core, the magnetic resistance between the rotor magnet and the rotor core (such as silicon steel sheet) is reduced, thereby reducing the magnet performance loss and torque loss; at the same time, the relative position between the rotor magnet and the rotor core can be stably maintained, making the rotor magnet not easy to slip or deviate. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] The features and advantages of the present invention will be clearly understood through the detailed description provided below with reference to the accompanying drawings. It should be understood that the following drawings are merely schematic and not necessarily drawn to scale, and thus cannot be regarded as limiting the present invention, wherein:

[0017] Figure 1 It is an exploded perspective view of a rotor assembly according to the prior art;

[0018] Figure 2 is an exploded perspective view of a rotor assembly according to an embodiment of the utility model;

[0019] Figure 3 is a top view of a single silicon steel sheet constituting a rotor core according to an embodiment of the utility model;

[0020] Figure 4 A perspective view showing a rotor core according to an embodiment of the present invention; and

[0021] Figure 5a and Figure 5b The claw structure and a single claw provided on a single silicon steel sheet are shown in partially enlarged views respectively. DETAILED DESCRIPTION

[0022] Embodiments of the present invention are described below with reference to the accompanying drawings. In the following description, many specific details are set forth so that those skilled in the art can more fully understand and implement the present invention. However, it is obvious to those skilled in the art that the implementation of the present invention may not have some of these specific details. In addition, it should be understood that the present invention is not limited to the specific embodiments described. On the contrary, any combination of the features and elements described below may be considered to implement the present invention, regardless of whether they relate to different embodiments. Therefore, the following aspects, features, embodiments and advantages are for illustrative purposes only and should not be regarded as elements or limitations of the claims unless clearly stated in the claims.

[0023] In the following, terms such as "first", "second", etc. are used to describe the elements of the present application. These terms are only used to distinguish the various elements, and are not used to limit the nature, order or number of these elements. The terms "including" and "having" are used to express an open-ended inclusive meaning, and mean that there may be additional elements / components in addition to the listed elements / components.

[0024] As mentioned in the background art, in existing motor designs, surface mounted magnets are usually held on the outer periphery of the rotor core by a plastic retainer. Figure 1 , which shows an exploded perspective view of a rotor assembly known in the prior art, the rotor assembly 100' comprises a rotor core 110' formed by stacking a plurality of silicon steel sheets, a plurality of rotor magnets 120', a plastic retainer 130' for retaining the rotor magnets 120' on the periphery of the rotor core 110', and an injection molded shell 140'. Figure 1 In the rotor assembly 100' shown, a plurality of radial grooves 131' are provided on the radial inner side of the plastic retainer 130', and the radial grooves 131' are intended to be aligned with the outer peripheral wall section of the rotor core 110' formed by stacked silicon steel sheets to define a space for accommodating the rotor magnet 120'. However, in order to facilitate the assembly of the rotor magnet, the space is designed so that the rotor magnet is arranged therein in a clearance fit manner, which may cause the rotor magnet to be loose after assembly, and due to the presence of the clearance, the magnetic resistance increases and the magnetic performance decreases.

[0025] To this end, the utility model proposes an improved solution, which enables the rotor magnet to be held or fixed in a manner with simpler assembly, better performance and more cost-effectiveness.

[0026] Specifically, Figure 2 As shown, the utility model proposes an improved rotor assembly 100 , which includes a rotor core 110 and a rotor magnet 120 . The rotor core 110 is formed by stacking a plurality of silicon steel sheets 111 together in the axial direction.

[0027] See also Figure 3 Each silicon steel sheet 111 includes a main body 1111 with a regular polygonal cross section and a plurality of claw structures 1112 radially extending outward from the main body 1111. The number of rotor magnets 120 is equal to the number of sides of the regular polygon. Figure 2 In the specific embodiment shown, ten rotor magnets are provided, and the cross section of the main body 1111 is a regular decagon.

[0028] Continue to see Figure 3Each claw structure 1112 is located at a vertex of a regular polygon. Each claw structure includes two claws 1112a and 1112b, and the two claws are symmetrically arranged on both sides of the vertex about an axis passing through the vertex where the claw structure is located (as an imaginary vertex of the regular polygon, not specifically shown in the figure) and the center O of the regular polygon.

[0029] In order to obtain Figure 4 In the rotor core 110 shown in the figure, every two adjacent silicon steel sheets 111 are stacked in a staggered manner at the same angle α in the same direction, so that a plurality of claw structure rows 112 spaced from each other are formed along the circumferential direction of the rotor core 110, and each claw structure row 112 includes two claw rows 1121 and 1122. Figure 4 As shown, one claw row 1122 or 1121 in each claw structure row 112 and one adjacent claw row 1121 or 1122 in the adjacent claw structure row 112 together define an accommodating groove 113 for receiving the rotor magnet 120 therein.

[0030] See especially Figure 5a and 5b In order to facilitate the smooth and convenient insertion of the rotor magnet 120 into the accommodating groove 113 and at the same time ensure the stable retention of the rotor magnet 120 relative to the rotor core 110, each claw 1112a, 1112b includes a guide section 11121 in the form of a ramp and a clamping section 11122 in the form of a straight line. Thus, when the rotor magnet 120 is inserted into the receiving groove 113 in the radial direction, firstly, all the guide sections 11121 in the two adjacent claw rows defining the receiving groove 113 provide guidance, and then all the clamping sections 11122 jointly hold the rotor magnet 120 against the outer peripheral wall of the rotor core 110 with a pre-tightening force. This can be, for example, because the opposite clamping sections 11122 defining the receiving groove 113 define an inlet width that is smaller than the width of the rotor magnet. Therefore, when the rotor magnet 120 is inserted in the radial direction under the guidance of the guide sections 11121, the clamping sections 11122 are forced to deform by overcoming the deformation force, and finally abut against the outer peripheral wall of the rotor core. At this time, the clamping sections in the claw rows can provide a suitable pre-tightening force for the rotor magnet 120.

[0031] According to a specific embodiment, each silicon steel sheet 111 constituting the rotor core 110 includes a plurality of claw structure groups (such as Figure 3 As shown in the figure, the two claw structure groups 1115 are included, so that the silicon steel sheet has a rotationally symmetrical structure, wherein each claw structure group may include at least two claw structures (such as Figure 3As shown in FIG. 1 , the at least two claw structures 1112 are respectively arranged at a corresponding number (eg, two) of mutually adjacent vertices of the regular polygon.

[0032] When the silicon steel sheets adopt the above arrangement, the angle between each two adjacent silicon steel sheets can be determined by the following formula: α = m × 360° / n, where α is the angle, n is the number of rotor magnets, and m is the number of claw structures included in each claw structure group. Figure 2-4 In the specific example of the silicon steel sheet shown, a single silicon steel sheet 111 is a regular decagon and includes two claw structure groups 1115 arranged in a rotationally symmetrical manner, and each claw structure group 1115 includes two claw structures 1112. In this way, each two adjacent silicon steel sheets 111 are riveted at α=72°, so that the final result is as follows: Figure 4 The rotor core shown in FIG. 110 has ten claw structure rows 112 spaced apart from each other formed in the circumferential direction of the rotor core, and the claw rows in the claw structure rows 112 together define ten receiving slots 113 for receiving the rotor magnets 120 .

[0033] According to another or other specific embodiments, each silicon steel sheet may include a plurality of claw structures arranged at equal angular spacings in the circumferential direction, so that the silicon steel sheet is a rotationally symmetrical structure, wherein the angle of misalignment between each two adjacent silicon steel sheets is determined by the following formula: α=360° / n, wherein α is the angle, and n is the number of rotor magnets. For example, a single silicon steel sheet 111 is a regular decagon, and the silicon steel sheet may include two claw structures 1112 spaced 180° apart from each other. In this way, each two adjacent silicon steel sheets 111 are riveted at α=36°.

[0034] However, those skilled in the art should understand that the number and specific arrangement of the claw structures (for example, in the form of multiple claw structure groups arranged at equal intervals or in the form of multiple claw structures arranged at equal intervals) can be selected according to actual needs and the required interference holding force.

[0035] In addition, if Figure 3 As shown, the silicon steel sheet 111 is also provided with a central through hole 1113. When all the silicon steel sheets 111 are stacked as shown in FIG. Figure 4 After the rotor core 110 shown in the figure, the stacked central through holes 1113 form a central channel for the bearing of the rotor shaft (not shown in the figure) to pass through. In addition, a plurality of positioning structures are arranged at intervals along the circumference of the central through hole 1113 of the silicon steel sheet 111. These positioning structures are used to position the rotor magnet 120 so as to facilitate magnetization of the rotor magnet. Figure 3In the specific embodiment shown, the positioning structure is designed as a part of the central through hole 1113, wherein the central through hole 1113 includes a through hole body 1113a and a positioning notch 1113b protruding radially outward from the through hole body 1113a and having a semicircular cross-section.

[0036] It should be known that after the rotor core 110 and the plurality of rotor magnets 120 are assembled together, the formed assembly is then subjected to injection molding to finally form an integrated rotor assembly. In order to facilitate the smooth flow of the injection molding material, a plurality of injection molding process holes 1114 are arranged in the circumferential direction around the central through hole 1113 on the main body 1111 of each silicon steel sheet 111 (see Figure 3 ).

[0037] The utility model also relates to a motor including the above-mentioned improved rotor assembly, which has reduced cost and simple assembly, and because there is reduced magnetic resistance between the rotor magnet and the rotor core (such as silicon steel sheet), the magnetic properties of the motor are greatly improved. The motor according to the utility model can be applied to multiple technical fields, for example, it can be applied to an electronic water pump to provide driving force for the electronic water pump as a power part. However, it should be understood that the motor according to the utility model is not limited to a water pump motor, and can also be other types of brushless motors and permanent magnet synchronous motors, such as power steering system motors, shift motors, clutch motors, brake motors, gasoline pumps, oil pumps and other fields.

[0038] According to the improved scheme of the utility model, by using silicon steel sheets to replace plastic retaining frames to fix the rotor magnets, the number of parts is reduced, the cost is more advantageous, and the difficulty of assembling parts is reduced. In addition, by arranging multiple claw structures on the silicon steel sheets, the claw structures include clamping sections to provide interference retention force, so that the rotor magnets can be tightly held relative to the rotor core with a certain pre-tightening force, thereby ensuring that the rotor magnets are tightly attached to the outer peripheral wall surface of the silicon steel sheets, avoiding the problem of large magnetic resistance and large magnetic performance loss caused by the gap, and at the same time, the relative position between the two can be stably maintained, so that the rotor magnets are not easy to slip and deviate.

[0039] For those skilled in the art, various modifications and variations may be made to the embodiments disclosed above without departing from the scope or spirit of the utility model. Other embodiments of the utility model will be apparent to those skilled in the art from the practice of the utility model disclosed in this specification. This specification and the examples disclosed therein should be considered to be illustrative only, and the true scope of the utility model is specified by the appended claims and their equivalents.

Claims

1. A rotor assembly, comprising a rotor magnet (120) and a rotor core (110), wherein the rotor core is formed by stacking a plurality of silicon steel sheets (111) in an axial direction, characterized in that: Each silicon steel sheet (111) comprises a main body (1111) having a regular polygonal cross section and a plurality of claw structures (1112) protruding radially outward from the main body; the number of the rotor magnets is equal to the number of sides of the regular polygon; Each claw structure (1112) is located at a vertex of a regular polygon and each claw structure includes two claws (1112a, 1112b), and the two claws are symmetrical about an axis passing through the vertex where the claw structure is located and the center (O) of the regular polygon; Wherein, every two adjacent silicon steel sheets are stacked in an offset manner at the same angle and in the same direction, so that a plurality of claw structure columns (112) spaced apart from each other are formed along the circumferential direction of the rotor core (110), and each claw structure column includes two claw columns (1121, 1122); wherein, a claw column in each claw structure column and one of the adjacent claw columns in the adjacent claw structure columns jointly define an accommodating groove (113) for receiving the rotor magnet (120) therein.

2. The rotor assembly according to claim 1, characterized in that Each claw comprises a guide section (11121) in the form of a ramp and a clamping section (11122) in the form of a straight line. The claw is designed so that when the rotor magnet (120) is radially inserted into the receiving groove (113), the guide sections in two adjacent claw rows defining the receiving groove provide guidance and the clamping section holds the rotor magnet against the outer peripheral wall of the rotor core (110) with a pre-tightening force.

3. The rotor assembly according to claim 2, characterized in that: Each silicon steel sheet (111) comprises a plurality of claw structure groups (1115) arranged at intervals along a circumferential direction, so that the silicon steel sheet presents a rotationally symmetrical structure, wherein each claw structure group (1115) comprises at least two claw structures (1112), and the at least two claw structures are respectively arranged at a corresponding number of mutually adjacent vertices, wherein the angle at which each two adjacent silicon steel sheets are offset and overlapped with each other is determined by the following formula: α=m×360° / n, wherein α is the angle, n is the number of rotor magnets, and m is the number of claw structures included in each claw structure group.

4. The rotor assembly according to claim 3, characterized in that: The number of the rotor magnets (120) is ten, the number of the claw structures included in each claw structure group (1115) is two, and the angle at which each two adjacent silicon steel sheets are offset and stacked is 72°.

5. The rotor assembly according to claim 2, characterized in that: The multiple claw structures of each silicon steel sheet are arranged at equal angular intervals in the circumferential direction, so that the silicon steel sheet has a rotationally symmetrical structure, wherein the angle between each two adjacent silicon steel sheets that are offset and overlapped with each other is determined by the following formula: α=360° / n, wherein α is the angle and n is the number of rotor magnets.

6. The rotor assembly according to any one of claims 1 to 5, characterized in that: Each silicon steel sheet (111) is provided with a central through hole (1113) and a plurality of positioning structures are arranged at intervals along the circumference of the central through hole to facilitate positioning of the rotor magnet (120) for magnetizing the rotor magnet.

7. The rotor assembly according to claim 6, characterized in that The central through hole (1113) comprises a through hole body (1113a) and a positioning notch (1113b) which protrudes radially outward from the through hole body and has a semicircular cross section, and the positioning notch serves as the positioning structure.

8. The rotor assembly according to any one of claims 1 to 5, characterized in that: The rotor core (110) and the rotor magnet (120) are formed into an integral piece by plastic sheathing.

9. A motor, characterized in that: The electric machine comprises a rotor assembly according to any one of claims 1 to 8.

10. An electronic pump, characterized in that: The electronic pump comprises the electric motor according to claim 9.

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