Rotor assembly, motor and electronic pump

Abstract

The utility model relates to a rotor assembly, which comprises a rotor magnet and a rotor core, the rotor core 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 cross section, and each silicon steel sheet is provided with a plurality of clamping jaw structure groups which are arranged at intervals along the circumferential direction, so that the silicon steel sheets are in a rotary symmetrical structure. Every two adjacent silicon steel sheets are overlapped in a staggered mode at the same angle in the same direction, so that a plurality of clamping jaw structure rows which are mutually spaced are formed in the circumferential direction of the rotor core. Each claw structure row comprises a first claw row composed of a plurality of first claws with a first orientation and a second claw row composed of a plurality of second claws with a second orientation opposite to the first orientation, and the first claws and the second claws are located at different axial positions. The utility model also relates to a motor and an electronic pump. According to the rotor assembly or the motor or the electronic pump, the cost benefit is higher, the performance is better, and the service life is longer.

Description

Technical Field

[0001] This utility model relates to the field of motor technology, specifically to a rotor assembly, a motor including the rotor assembly, and an electronic pump including the motor. Background Technology

[0002] In brushless motors, rotors with surface-mount magnets are often used. These surface-mount magnets can be held on the outer periphery of a rotor core, for example, made of stacked silicon steel sheets, by a cage. Then, the rotor core, magnets, and cage are injection molded together for fixation.

[0003] In existing technologies, a plastic retainer is typically used to hold the magnet radially between the retainer and the outer peripheral surface of the rotor core. However, this method suffers from high mold costs for the retainer and inconvenient assembly. Furthermore, because the magnet needs to be inserted between the silicon steel sheet and the plastic retainer, a gap is often required. A large gap can lead to loosening of the magnet after assembly, causing it to slip or even fall off during the secondary injection molding process. Additionally, the gap increases the magnetic reluctance between the magnet and the silicon steel sheet, reducing magnetic performance. Conversely, an excessively small gap can cause difficulty or failure in magnet insertion, as well as severe scratches on the magnet surface.

[0004] Furthermore, while existing technologies disclose a method to eliminate the need for a plastic cage by staggered stacking of silicon steel sheets in the rotor core, this type of rotor core cannot accommodate rotors of different diameters. Especially when manufacturing small-diameter rotors, the manufacturing process of this rotor core presents significant challenges, and the root of the chucks is prone to yielding failure due to excessive material removal. Additionally, the excessive number of contact points between the rotor core and the rotor magnet leads to significant magnetic leakage in the rotor magnet, which negatively impacts its function. Therefore, an improved fixing structure for the rotor magnet is needed. Utility Model Content

[0005] The purpose of this utility model is to solve at least one of the above-mentioned problems and / or other problems existing in the prior art.

[0006] According to one aspect of the present invention, a rotor assembly is provided, comprising a rotor magnet and a rotor core. The rotor core is formed by stacking multiple silicon steel sheets along an axial direction. Each silicon steel sheet includes a main body with a regular polygonal cross-section and multiple claw structure groups spaced apart along the circumferential direction of the main body, such that the silicon steel sheet has a rotationally symmetric structure. Each claw structure group includes only two claws, which are respectively disposed at two adjacent vertices of the regular polygon and are symmetrical about an axis. The axis passes through the midpoint of the side of the regular polygon defined by the two adjacent vertices and the... The center; wherein, each pair of adjacent silicon steel sheets are stacked at the same angle and in the same direction, such that multiple rows of claw structures are spaced apart from each other along the circumferential direction of the rotor core; each row of claw structures includes a first claw row consisting of multiple first claws having a first orientation and a second claw row consisting of multiple second claws having a second orientation opposite to the first orientation, each first claw and second claw in each row of claw structures being in a different axial position; the first claw row in each row of claw structures and the second claw row in the adjacent row of claw structures together define a receiving groove therein for receiving a rotor magnet.

[0007] In one implementation, each claw includes a claw body and a claw root, and the maximum width of each claw at the claw root is greater than the maximum width of the claw at the claw body.

[0008] In one implementation, the root of each jaw defines a first edge close to another jaw included in the same jaw structure group and a second edge distant from the other jaw, the first edge including a straight portion and the second edge including a curved portion; the curved portion extends such that the width of the jaw at the jaw root gradually increases as it approaches the body of the silicon steel sheet.

[0009] In one embodiment, the jaw body of the jaw defines a ramp-shaped guide section and a straight clamping section. The jaw is designed such that when the rotor magnet is inserted radially into the receiving slot, the guide section in two adjacent jaw rows defining the receiving slot provides guidance and the clamping section holds the rotor magnet against the outer peripheral wall of the rotor core with a preload force.

[0010] As one implementation, the angle at which two adjacent silicon steel sheets are staggered and stacked is determined by the following formula: α = m × 360° / n, where α is the angle, n is the number of rotor magnets, and m is a positive integer.

[0011] In one implementation, each silicon steel sheet is provided with two claw structure groups, and the number of rotor magnets is ten. The angle at which two adjacent silicon steel sheets are staggered and stacked is 72°.

[0012] In one embodiment, the rotor core and the rotor magnet are molded into a single piece by plastic overlay.

[0013] According to another aspect of the present invention, an electric motor is provided, the electric motor comprising the rotor assembly as described above.

[0014] According to another aspect of the present invention, an electronic pump is provided, the electronic pump comprising the motor described above.

[0015] According to the present invention, the rotor core or rotor assembly eliminates the need for expensive plastic cages and injection molds, greatly reducing costs and decreasing the magnetic resistance between the rotor magnet and the rotor core (such as silicon steel sheets), thereby reducing magnet performance loss and torque loss. In addition, by setting multiple claw structure groups on each silicon steel sheet, and making each claw structure group include only two claws spaced apart at adjacent vertices of the silicon steel sheet, structural reinforcement can be designed at the root of the claws to avoid claw yielding failure. At the same time, while ensuring sufficient holding force on the rotor magnet, the number of contact points between the claws and the rotor magnet can be reduced, thus effectively reducing the leakage flux of the rotor magnet and thus maximizing the function of the rotor magnet. Attached Figure Description

[0016] The features and advantages of this utility model will become clear from the following detailed description provided with reference to the accompanying drawings. It should be understood that the following drawings are merely schematic and not necessarily drawn to scale, and therefore should not be considered as limitations on this utility model, wherein:

[0017] Figure 1 An exploded view of a rotor assembly according to an embodiment of the present invention is shown;

[0018] Figure 2 The composition is shown Figure 1 A schematic diagram of the silicon steel sheet structure of the rotor core;

[0019] Figure 3 It shows Figure 1 A three-dimensional view of the rotor core; and

[0020] Figure 4 Partially shown in Figure 2 The structure consists of a single claw set on the outer periphery of a silicon steel sheet. Detailed Implementation

[0021] Embodiments of the present invention are described below with reference to the accompanying drawings. In the following description, numerous specific details are set forth to enable those skilled in the art to more fully understand and implement the present invention. However, it will be apparent to those skilled in the art that implementations of the present invention may not include some of these specific details. Furthermore, it should be understood that the present invention is not limited to the specific embodiments described. Rather, the present invention can be conceived to be implemented with any combination of the features and elements described below, 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 construed as elements or limitations of the claims unless expressly set forth in the claims.

[0022] The terms "first" and "second" are used below to describe the elements of this application. These terms are used only to distinguish the individual elements and not to limit the nature, order, or number of these elements. The terms "comprising" and "having" are used to indicate an open-ended inclusion and mean that there may be additional elements / components besides those listed.

[0023] As mentioned in the background section, in existing motor designs, the rotor magnets are arranged in the cage with a gap fit. This can lead to loosening of the rotor magnets after assembly, and the gaps increase magnetic reluctance and reduce magnetic performance. Furthermore, existing rotor designs that omit the plastic cage present problems such as difficult manufacturing processes, premature structural failure, and significant magnetic leakage of the rotor magnets when manufacturing small-diameter rotors. Therefore, this invention proposes an improved solution that allows for a simpler assembly method, better performance, and greater cost-effectiveness in retaining the rotor magnets.

[0024] Specifically, Figure 1 An exploded view of a rotor assembly according to an embodiment of the present invention is shown. The present invention proposes an improved rotor assembly 1, which includes a rotor core 2 and a plurality of rotor magnets 3. The rotor core 2 may be formed by stacking a plurality of silicon steel sheets 21 along the axial direction. Figure 2 A schematic diagram of a single silicon steel sheet 21 is shown. The silicon steel sheet 21 includes a main body 211 with a regular polygonal cross-section and a plurality of claw structure groups 212 spaced apart along the circumferential direction of the main body, such that the silicon steel sheet 21 has a rotationally symmetric structure. In the rotor assembly, the number of rotor magnets 3 is equal to the number of sides of the regular polygon of the silicon steel sheet. In a specific embodiment of this utility model, for example in Figure 1In the specific embodiment shown, ten rotor magnets 3 are provided, and the main body of the silicon steel sheet 21 has a regular decagonal cross-section. Each silicon steel sheet 21 is provided with two claw structure groups 212, which are arranged opposite to each other in the diametrical direction. Of course, according to actual design requirements, other numbers of rotor magnets and corresponding silicon steel sheet structures are also feasible.

[0025] Unlike the applicant's previous rotor design, in the rotor assembly according to this embodiment of the utility model, each claw structure group 212 includes only two claws 2121, and the two claws 2121 are respectively disposed at two adjacent vertices of the regular polygon. Specifically, as shown... Figure 2 As shown, only one single latch (rather than multiple latches) is provided at a single vertex, and two latches located at two adjacent vertices are symmetrical about an axis that passes through the midpoint of the side of the regular polygon defined by the two adjacent vertices and the center O of the regular polygon, as shown. Figure 2 As shown.

[0026] Due to the single-jaw design, not only is material removal at the jaw root avoided, but it also allows for the design of reinforcing structures at the jaw root. For example, see [link to relevant documentation]. Figure 2 and Figure 4 Each jaw 2121 includes a jaw body 2121a and a jaw root 2121b, and the maximum width W of each jaw at the jaw root is... max1 The width W of the jaw is greater than the maximum width of the jaw body. max2 See especially Figure 4 Each jaw has a jaw root 2121b that defines a first edge near another jaw included in the same jaw structure group and a second edge away from the other jaw. The first edge includes a straight portion S1, and the second edge includes a curved portion S2. The curved portion S2 extends such that the width of the jaw 2121 at the jaw root 2121b gradually increases with increasing proximity to the body 211 of the silicon steel sheet 21 (e.g., ...). Figure 4 In the middle, the width gradually increases from W1, W2... to W max1 Therefore, the structural strength at the root 2121b of the chuck is enhanced, thereby reducing the risk of chuck yield failure.

[0027] Figure 3 A perspective view of rotor core 2 is shown. (For the formation of...) Figure 3The rotor core shown has two adjacent silicon steel sheets 21 stacked at the same angle and in the same direction, staggered together, forming multiple rows 22 of claw structures spaced apart from each other along the circumferential direction of the rotor core. Each row 22 of claw structures includes a first row 221 composed of multiple first claws having a first orientation and a second row 222 composed of multiple second claws having a second orientation opposite to the first orientation. See in particular... Figure 3 The first and second jaws included in each jaw structure row 22 are axially offset from each other (i.e., each jaw is in a different axial position). This allows for a reduction in the number of jaws that contact the corresponding rotor magnet 3. The first jaw row in each jaw structure row and the second jaw row in the adjacent jaw structure row together define a receiving groove 23 in which the rotor magnet 3 is received.

[0028] It should be understood that the aforementioned special jaw arrangement is highly advantageous. In the applicant's previous design, a structure with, for example, a double jaw at a single apex was used. While this eliminated the need for a plastic retainer and reduced costs, the manufacturability of this double jaw design was limited in applications with rotors having smaller outer diameters. Furthermore, because material removal was required at the jaw root to meet manufacturability requirements, the jaw root was prone to yielding after the rotor magnet was pressed in, resulting in insufficient rotor magnet holding force and thus a higher risk in mass production. However, the single jaw design in this invention not only avoids the limitations of the stamping gap between the double jaws but also effectively reduces rotor magnet leakage by reducing the number of contact points between the jaws and the rotor magnet, while ensuring sufficient holding force after the rotor magnet is pressed in, thus optimally ensuring the function of the rotor magnet.

[0029] To facilitate the smooth and convenient insertion of the rotor magnet 3 into the receiving slot 23 while ensuring the stable holding of the rotor magnet 3 relative to the rotor core 2, please refer to [reference needed]. Figure 4 Each jaw 2121 has a jaw body 2121a comprising a ramp-shaped guide section 21211 and a straight clamping section 21212. Thus, when the rotor magnet 3 is inserted radially into the receiving groove 23, it is first guided by all the guide sections 21211 in two adjacent jaw rows defining the receiving groove 23, and then all the clamping sections 21212 together hold the rotor magnet 3 against the outer peripheral wall of the rotor core 2 with a preload force. This can be, for example, because the opposing clamping sections defining the receiving groove 23 define an inlet width smaller than the width of the rotor magnet 3. Therefore, when the rotor magnet 3 is inserted radially by the guidance of the guide sections 21211, it overcomes the deformation force of the clamping sections 21212, forcing the clamping sections to deform and ultimately abut against the outer peripheral wall of the rotor core 2. At this time, the clamping sections in the jaw rows can provide a suitable preload force to the rotor magnet.

[0030] To form the aforementioned multiple rows of claw structures, the angle at which two adjacent silicon steel sheets 21 are staggered and stacked 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 a positive integer. It should be noted that the value of m should avoid a situation where two adjacent silicon steel sheets completely overlap after rotating by the aforementioned angle.

[0031] For example, in Figure 1 In the specific example of the silicon steel sheet shown, a single silicon steel sheet 21 is a regular decagon and includes two claw structure groups 212 arranged in a rotationally symmetrical manner, each claw structure group 212 including two claws 2121. Thus, every two adjacent silicon steel sheets are rotated and riveted together at α = 72°, resulting in a final shape as shown... Figure 3 The rotor core shown has ten spaced-apart rows of claw structures formed along its circumferential direction, which together define ten receiving slots for receiving rotor magnets. However, those skilled in the art will understand that the number and specific arrangement of the claw structures can be selected according to actual needs and the required interference holding force.

[0032] It should be understood that after the rotor core 2 and multiple rotor magnets 3 are assembled together, the resulting components are then injection molded to form a single rotor assembly.

[0033] This invention also relates to a motor comprising the aforementioned improved rotor assembly, which has reduced cost and simple assembly, and significantly improved magnetic performance due to reduced magnetic resistance between the rotor magnet and the rotor core (such as silicon steel sheets). The motor according to this invention can be applied in various technical fields, such as in electric water pumps as a power source to provide driving force. However, it should be understood that the motor according to this invention is not limited to water pump motors, but can also be other types of brushless motors and permanent magnet synchronous motors, such as power steering system motors, gear shift motors, clutch motors, brake motors, fuel pumps, oil pumps, etc.

[0034] Various modifications and variations can be made to the embodiments disclosed above without departing from the scope or spirit of this invention. Other embodiments of this invention will be apparent to those skilled in the art based on the practice of this invention disclosed in this specification. This specification and the examples disclosed herein should be considered illustrative only, and the true scope of this invention is defined by the appended claims and their equivalents.

Claims

1. A rotor assembly comprising a rotor core (2) and a plurality of rotor magnets (3), the rotor core being made of a plurality of silicon steel sheets (21) stacked in an axial direction, each silicon steel sheet comprising a main body (211) having a cross section of a regular polygon and a plurality of claw structure groups (212) arranged at intervals in a circumferential direction of the main body, such that the silicon steel sheet (21) has a rotational symmetrical structure; characterized in that each claw structure group (212) comprises only two claws (2121) respectively arranged at two adjacent vertices of the regular polygon and symmetric about an axis passing through a midpoint of an edge of the regular polygon defined by the two adjacent vertices and a center (O) of the regular polygon; wherein each two adjacent silicon steel sheets (21) are stacked at intervals in the same direction at the same angle, such that a plurality of claw structure columns (22) are formed at intervals in a circumferential direction of the rotor core (2); each claw structure column comprises a first claw column (221) composed of a plurality of first claws having a first orientation and a second claw column (222) composed of a plurality of second claws having a second orientation opposite to the first orientation, each first claw and second claw in each claw structure column being at a different axial position; wherein the first claw column in each claw structure column and the second claw column in an adjacent claw structure column together define a receiving slot (23) for receiving a rotor magnet (3) therein.

2. The rotor assembly of claim 1, wherein Each pawl (2121) includes a pawl body (2121a) and a pawl root (2121b), each pawl having a maximum width (W max1 ) at the pawl root that is greater than a maximum width (W max2 ) of the pawl at the pawl body.

3. The rotor assembly of claim 2, wherein, A claw root of each claw defines a first edge close to another claw included in the same claw structure group and a second edge away from the other claw, the first edge comprising a straight portion (SI) and the second edge comprising a curved portion (S2); the curved portion (S2) extends such that a width of the claw at the claw root gradually increases close to the main body (211) of the silicon steel sheet.

4. The rotor assembly of any one of claims 1 to 3, wherein, A claw body (2121a) of the claw defines a guide section (21211) in the form of a slope and a clamping section (21212) in the form of a straight line, the claw being designed such that, when the rotor magnet (3) is inserted into the receiving slot (23) in a radial direction, the rotor magnet (3) is guided by the guide sections in the two adjacent claw columns defining the receiving slot and is held against the outer peripheral wall of the rotor core (2) by the clamping sections with a pre-tightening force.

5. The rotor assembly of any one of claims 1 to 3, wherein, The angle at which each two adjacent silicon steel sheets (21) are stacked at intervals with each other is determined by the formula: a = m x 360° / n, wherein a is the angle, n is the number of rotor magnets, and m is a positive integer.

6. The rotor assembly of claim 5, wherein, There are two claw structure groups (212) on each silicon steel sheet (21), and the number of rotor magnets (3) is ten.

7. The rotor assembly of claim 6, wherein The angle at which each two adjacent silicon steel sheets (21) are stacked at intervals with each other is 72°.

8. The rotor assembly of any one of claims 1 to 3, wherein, The rotor core (2) and the rotor magnets (3) are integrally formed by plastic overmolding.

9. An electric machine characterized by The motor comprises the rotor assembly according to any one of claims 1 to 8.

10. An electronic pump characterized by, The electronic pump comprises the motor according to claim 9.

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