Rotor assembly and sound wave motor with same

Abstract

The rotor assembly comprises a shaft bracket and at least two magnet sheets, the center of the shaft bracket is provided with a shaft core, the outer surface of the shaft bracket is provided with at least two slots, the at least two slots are arranged at intervals around the circumferential direction of the shaft core, and each slot extends along the axis of the shaft core; the at least two magnet sheets correspond to the at least two slots one by one, and each magnet sheet is inserted into the slot along the axial direction of the shaft core, so that the magnet sheets are fixed on the shaft bracket. According to the rotor assembly and the sound wave motor with the rotor assembly, the magnet sheets are matched with the slots in an axial plugging mode, and compared with a traditional bonding mode, the plugging fixing mode has higher mechanical strength and reliability, so that the magnet sheets are effectively prevented from being separated from the shaft bracket during falling or vibration, and the service life of the rotor assembly is prolonged. The more strict drop test can be passed, and the reliability and the service life of the product are obviously improved. In addition, due to the axial insertion design, the assembly process is greatly simplified, and the production efficiency is improved.

Description

TECHNICAL FIELD

[0001] The utility model relates to a motor especially relates to a rotor assembly and have its acoustic motor. BACKGROUND

[0002] The acoustic motor is a key component in the electric toothbrush, and high-frequency vibration is realized to achieve efficient cleaning, and can reach tens of thousands of times per minute. Its working principle includes eccentric and linear two types, respectively using centrifugal force and electromagnetic action to produce vibration. Compared with the traditional motor, the acoustic motor has the advantages of low noise, reducing wear and tear, prolonging service life, etc., and is widely used in daily oral care and professional dental equipment.

[0003] The acoustic motor in the related art usually includes a stator and a rotor, and the rotor includes an axle holder and a magnet piece, the axle holder is provided with an axle core, and the magnet piece is adhesively fixed on the axle holder. The structure design of adhesively fixing the magnet piece on the axle holder has the problems of poor reliability and inconvenient assembly, and in the drop test, the magnet piece and the axle holder may be separated. In addition, the connection strength between the magnet piece and the axle holder gradually decreases after long-term use, which affects the reliability and service life. SUMMARY

[0004] The utility model aims at at least in a certain extent solves one of the technical problems among the related art. For this reason, the purpose of the utility model is to propose a rotor assembly and have its acoustic motor.

[0005] In order to achieve the above-mentioned purpose, according to the rotor assembly of the utility model embodiment, including:

[0006] The axle holder is provided with an axle core in the center, and the outer surface of the axle holder is provided with at least two insertion grooves, and the at least two insertion grooves are arranged at intervals around the circumference of the axle core, and each insertion groove extends along the axis of the axle core;

[0007] At least two magnet pieces, at least two magnet pieces correspond to at least two insertion grooves one by one, and each magnet piece is inserted into the insertion groove along the axial direction of the axle core, so that the magnet piece is fixed on the axle holder.

[0008] In addition, the rotor assembly according to the above-mentioned embodiment of the utility model can also have the following additional technical features:

[0009] According to one embodiment of the utility model, the magnet piece and the insertion groove are four.

[0010] According to one embodiment of the utility model, two of the four magnet pieces form a group to form two magnet groups, and the two magnet groups are symmetrical about an axial plane, and the axial plane coincides with the axis of the axle core.

[0011] The magnetizing direction of one of the magnet pieces in each of the magnet groups is radial magnetization with the south pole on the radial outer side, and the magnetizing direction of the other magnet piece in each of the magnet groups is radial magnetization with the north pole on the radial outer side.

[0012] According to an embodiment of the present application, the outer surface of the shaft support is provided with four strip-shaped portions, which are arranged at intervals along the circumference of the shaft core;

[0013] Each of the strip-shaped portions extends along the axial direction of the shaft core, and two opposite side surfaces of each of the strip-shaped portions are respectively provided with first guide grooves extending along the length direction of the strip-shaped portion; the first guide grooves on the adjacent side surfaces of two adjacent strip-shaped portions define the insertion slot.

[0014] According to an embodiment of the present application, the width dimensions of two adjacent strip-shaped portions are different, and the widths of two strip-shaped portions opposite in the radial direction are the same, and one of the two adjacent strip-shaped portions with a larger width has a symmetrical structure about the axial plane.

[0015] According to an embodiment of the present application, the outer surface of one of the two adjacent strip-shaped portions with a larger width has a protruding portion protruding outward in the radial direction.

[0016] According to an embodiment of the present application, the middle of the width direction of the protruding portion is provided with a groove extending along the length direction of the strip-shaped portion.

[0017] According to an embodiment of the present application, the strip-shaped portion comprises a neck portion and a crown portion, the crown portion is arranged at one end of the neck portion away from the shaft support, and the width of the crown portion is greater than the width of the neck portion, so as to define the first guide groove through the crown portion and the neck portion.

[0018] The two side surfaces of the magnet piece are respectively provided with second guide grooves, the second guide grooves on the adjacent side surfaces of two adjacent magnet pieces define a clamping slot, and the crown portion is inserted into the clamping slot along the axial direction of the shaft core.

[0019] According to an embodiment of the present application, the magnet piece is a tile-shaped magnet, and the shaft support is made of a magnetic conductive material and has a cylindrical structure.

[0020] On the other hand, according to an embodiment of the present application, an acoustic motor comprises:

[0021] A housing;

[0022] A stator core fixed in the housing, the stator core has two radially opposite stator teeth, and the inner side surfaces of the two stator teeth opposite to each other are arc surfaces.

[0023] a coil wound on the stator teeth to generate a magnetic field;

[0024] A rotor assembly as described above is arranged in the housing and between the two arc surfaces to reciprocate under the driving of the magnetic field.

[0025] According to the rotor assembly and the acoustic motor having the same, the plurality of slots are arranged on the outer surface of the shaft support along the circumferential direction of the shaft core, and the magnet pieces are matched with the slots through the axial insertion mode. Compared with the traditional adhesive mode, the insertion mode has higher mechanical strength and reliability, effectively prevents the magnet pieces from being separated from the shaft support when falling or vibrating, can pass more rigorous drop test, and significantly improves the product reliability and service life. In addition, the axial insertion design greatly simplifies the assembly process and improves the production efficiency.

[0026] The additional aspects and advantages of the present application will be given in part in the following description, and will become apparent from the following description, or will be learned by practice of the present application. BRIEF DESCRIPTION OF DRAWINGS

[0027] 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 embodiment or prior art description. Obviously, the drawings in the following description only show some embodiments of the present application, and other drawings can also be obtained according to the structures shown in the drawings without creative labor for those skilled in the art.

[0028] Figure 1 is a structural schematic view of the rotor assembly of the embodiment of the present application;

[0029] Figure 2 is an end side schematic view of the rotor assembly of the embodiment of the present application;

[0030] Figure 3 is an end side schematic view of the shaft support in the rotor assembly of the embodiment of the present application;

[0031] Figure 4 is an end side schematic view of the four magnet pieces in the rotor assembly of the embodiment of the present application;

[0032] Figure 5 is an exploded view of the rotor assembly of the embodiment of the present application;

[0033] Figure 6 is a structural schematic view of the acoustic motor of the embodiment of the present application;

[0034] Figure 7 is a sectional view of the acoustic motor of the embodiment of the present application.

[0035] Reference signs:

[0036] 10, shaft support;

[0037] 101, strip part;

[0038] 1011, neck part;

[0039] 1012, crown part;

[0040] 1013, protrusion part;

[0041] H10a, first guide groove;

[0042] H10b, recess;

[0043] 11, shaft core;

[0044] 111, drive shaft;

[0045] 20, magnet piece;

[0046] H20, second guide groove;

[0047] 30, housing;

[0048] 40, stator core;

[0049] 401, stator tooth;

[0050] S40, arc surface;

[0051] 50, coil.

[0052] The realization, functional features and advantages of the present application will be further described with reference to the embodiments and the accompanying drawings. DETAILED DESCRIPTION

[0053] The embodiments of the present application will be described in detail below, and examples of the embodiments are shown in the drawings, wherein the same or similar reference signs represent the same or similar elements or elements having the same or similar functions throughout. The embodiments described below by reference to the drawings are exemplary and are intended to explain the present application, and cannot be understood as limiting the present application, and all other embodiments obtained by those skilled in the art based on the embodiments in the present application without creative labor fall within the scope of protection of the present application.

[0054] In the description of the present invention, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise", "axial", "circumferential", "radial", etc., indicating the orientation or position relationship, are based on the orientation or position relationship shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present invention.

[0055] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of the technical features being referred to. Thus, a feature specified as "first" or "second" may explicitly or implicitly include one or more of such features. In the description of this utility model, "plurality" means two or more, unless otherwise specifically defined.

[0056] In this utility model, unless otherwise specified or limited, the terms "installed," "connected," "connect," "fixed," etc. should be understood in a broad sense. For example, they can refer to fixed connection, detachable connection, or integral connection; mechanical connection or electrical connection; direct connection or indirect connection through an intermediate medium; and internal communication between two components. Those skilled in the art will understand the specific meanings of the above terms in this utility model based on specific circumstances.

[0057] In the present invention, unless otherwise expressly specified or limited, a first feature being "above" or "below" a second feature may include the first and second features being in direct contact, or may include the first and second features being in contact not directly but through another feature between them. Moreover, a first feature being "above," "above," and "above" a second feature may include the first feature being directly above or obliquely above the second feature, or may simply mean that the first feature is higher in level than the second feature. A first feature being "below," "below," and "below" a second feature may include the first feature being directly below or obliquely below the second feature, or may simply mean that the first feature is lower in level than the second feature.

[0058] The rotor assembly and the sonic motor having the same according to the embodiment of the present invention will be described in detail below with reference to the accompanying drawings.

[0059] Reference Figures 1 to 5 As shown, the rotor assembly provided according to an embodiment of the present invention includes a shaft frame 10 and at least two magnet pieces 20 .

[0060] Specifically, the shaft frame 10 is provided with a shaft core 11, and an outer surface of the shaft frame 10 is provided with at least two slots, and the at least two slots are arranged at intervals in a circumferential direction of the shaft core 11, and each of the slots extends along an axis of the shaft core 11.

[0061] The shaft frame 10 can be made of metal, and preferably, the shaft frame 10 is made of a magnetic conductive material, for example, is formed by axially stacking silicon steel sheets, so that the magnetic force of the rotor assembly as a whole can be enhanced. The shaft core 11 can be made of a metal material with high structural strength, such as stainless steel, and the shaft core 11 and the shaft frame 10 can be fixed by interference fit or key connection. The slot extends in the axial direction, and the depth, width and length of the slot match the size of the magnet piece 20. At least one end of the slot is open, facilitating the axial insertion of the magnet piece 20 into the slot.

[0062] The at least two magnet pieces 20 correspond to the at least two slots one by one, and each of the magnet pieces 20 is inserted into the slot in the axial direction of the shaft core 11, so that the magnet piece 20 is fixed on the shaft frame 10.

[0063] The magnet piece 20 is made of a permanent magnet, and the shape and size of the magnet piece 20 need to match the slot. The cooperation between the magnet piece 20 and the slot is by interference fit or small gap fit, as long as the magnet piece 20 can be smoothly inserted into the slot, and at the same time, there is enough fixing action between them, and they are not easy to fall off.

[0064] In this application, the magnet piece 20 is fixed by an axial insertion method, and each magnet piece 20 can accurately correspond to a slot. During assembly, the magnet piece 20 is fixed by being inserted into the corresponding slot in the axial direction. This cooperation makes full use of the constraint of the slot, which is a mechanical constraint. Compared with adhesive fixing, this method has more reliable fixing effect, and avoids the problem of adhesive aging.

[0065] According to the rotor assembly provided by the embodiment of the utility model, a plurality of slots are arranged on the outer surface of the shaft frame 10 in the circumferential direction of the shaft core 11, and the magnet piece 20 is cooperated with the slot by an axial insertion method. Compared with the traditional adhesive method, this insertion type fixing method has higher mechanical strength and reliability, effectively prevents the magnet piece 20 from falling off the shaft frame 10 when falling or vibrating, can pass more rigorous drop test, and significantly improves the product reliability and service life. In addition, the axial insertion design greatly simplifies the assembly process and improves the production efficiency.

[0066] It can be understood that the number of the magnet pieces 20 varies according to the performance requirements of the rotor assembly and the application in specific motor products, for example, in some examples, the number of the magnet pieces 20 is two, and correspondingly, the number of the slots is also two, the two slots are arranged radially symmetrically on the shaft stand 10. The structure of the symmetric arrangement of the two magnet pieces 20 generally forms a rotor structure with a rectangular cross section.

[0067] And in some other examples, the number of the magnet pieces 20 and the slots is four. Generally, the four magnet pieces 20 are arranged circumferentially at intervals, which can form a rotor structure with a generally circular cross section.

[0068] Referring to Figure 2 In an embodiment of the utility model, two of the four magnet pieces 20 form a group to form two magnet groups, the two magnet groups are symmetric about an axial plane, and the axial plane coincides with the axis of the shaft core 11. This symmetric layout not only balances the magnetic force distribution, but also facilitates the rotor assembly to remain at a horizontal reference position when the rotor assembly stops rotating.

[0069] The magnetization direction of one magnet piece 20 in each magnet group is radial magnetization with the south pole on the radial outside, and the magnetization direction of the other magnet piece 20 in each magnet group is radial magnetization with the north pole on the radial outside. This magnetization mode enables the entire rotor to produce a good electromagnetic coupling effect with the stator during operation.

[0070] In the embodiment, four magnet pieces 20 are used, and through the layout of the four magnet pieces 20 and the magnetization direction, a high-efficiency uniform magnetic field distribution is formed, which improves the working efficiency of the motor. Moreover, the symmetric arrangement of the four magnet pieces 20 ensures the dynamic balance of the rotor and reduces the operating noise.

[0071] Referring to Figures 1 to 3 In an embodiment of the utility model, the outer surface of the shaft stand 10 is provided with four strip-shaped parts 101, and the four strip-shaped parts 101 are arranged at intervals along the circumference of the shaft core 11.

[0072] Each strip-shaped part 101 extends along the axis of the shaft core 11, and each strip-shaped part 101 is provided with two opposite side surfaces extending along the length direction of the strip-shaped part 101; the first guide grooves H10a on the adjacent side surfaces of the adjacent two strip-shaped parts 101 define the slots.

[0073] That is to say, each strip-shaped part 101 is a protruding structure protruding outward in the radial direction on the shaft stand 10, and the length direction of the strip-shaped part 101 is parallel to the shaft core 11. Preferably, the material of the strip-shaped part 101 is the same as the body of the shaft stand 10, and is generally manufactured by an integral molding process, which ensures the integrity and reliability of the structure.

[0074] The first guide groove H10a is provided on two opposite sides of each of the strip-shaped portions 101 and extends along the length direction of the strip-shaped portion 101. The cross section of the first guide groove H10a is configured to cooperate with the magnet piece 20. The slot is formed by the first guide grooves H10a on the two adjacent strip-shaped portions 101. That is, the first guide grooves H10a on the two adjacent strip-shaped portions 101 are oppositely arranged, and the space between the two first guide grooves H10a forms the slot for mounting the magnet piece 20.

[0075] During installation, one end of the magnet piece 20 is aligned with the opening at one end of the slot, and the magnet piece 20 is inserted into the slot from the opening by force. At this time, the two sides of the magnet piece 20 are inserted into the two oppositely arranged first guide grooves H10a and slid into place along the first guide grooves H10a.

[0076] In the embodiment, the oppositely arranged first guide grooves H10a of the two strip-shaped portions 101 define the slot, which not only ensures the reliability and stability of the fixation of the magnet piece 20, but also ensures that most of the area of the magnet piece 20 is exposed outside the shaft bracket 10 when the magnet piece 20 is mounted on the shaft bracket 10, thereby ensuring the magnetic field strength.

[0077] Referring to Figure 2 and Figure 3 In one embodiment of the utility model, the width of the two adjacent strip-shaped portions 101 is different, and the width of the two strip-shaped portions 101 opposite in the radial direction is the same. One of the two adjacent strip-shaped portions 101 with a larger width is symmetrically arranged about the axial plane.

[0078] In the embodiment, the four strip-shaped portions 101 are arranged in two groups, and the two strip-shaped portions 101 in each group are arranged opposite in the radial direction. Because the first guide grooves H10a on the two sides of the strip-shaped portion 101 jointly form the slot of the magnet piece 20, the strip-shaped portions 101 with different widths enable the two groups of magnet pieces 20 to be arranged opposite and have a certain spacing. This layout meets the requirements of the magnetic field distribution in some motor applications, such as the positioning part in the motor, which has two stator teeth 401 arranged opposite in the radial direction, and each stator tooth 401 has a coil 50 wound thereon. In this way, the two groups of magnet pieces 20 correspond to the two stator teeth 401 one by one, and a good electromagnetic coupling effect can be formed. In addition, this design also enables the rotor assembly to easily achieve dynamic balance, and the rotor assembly can be kept at a horizontal reference position when the rotor assembly stops rotating.

[0079] Referring to Figure 2 , Figure 3 and Figure 5As shown in the utility model in one embodiment, the outer surface of one of the two adjacent strip-shaped parts 101 with larger width has a protruding part 1013 protruding radially outward.

[0080] In the motor, when the rotor assembly stops rotating, the magnetic sheet of the rotor assembly has a magnetic attraction effect, at this time, the rotor assembly is attracted to the stator core 40. In this embodiment, by arranging the radial protruding part 1013 on the outer surface of the wider strip-shaped part 101, the width dimension between the two protruding parts 1013 can be increased, and at the same time, the protruding part 1013 can form two protruding positions on both sides of the horizontal reference position, and when the two protruding positions are attracted to the stator core 40, two balance forces are formed, which can more easily keep the rotor assembly at the horizontal reference position when the rotor assembly stops rotating.

[0081] Preferably, the protruding part 1013 is provided with a groove H10b extending along the length direction of the strip-shaped part 101 in the middle of the width direction. The groove H10b can reduce the weight of the shaft stand 10, so that the rotor assembly can change direction more quickly during reciprocating vibration, and improve the response speed during reverse. On the other hand, the two protruding parts 1013 on both sides of the rotor assembly correspond to four protruding points respectively, so as to better achieve the balance effect. In addition, the groove H10b can form an air duct to improve air convection when the rotor assembly rotates at high speed, and reduce wind resistance.

[0082] Referring to Figures 2 to 3 As shown in some embodiments of the utility model, the strip-shaped part 101 comprises a neck part 1011 and a crown part 1012, the crown part 1012 is arranged on the neck part 1011 away from one end of the shaft stand 10, and the width of the crown part 1012 is greater than the width of the neck part 1011, so as to define the first guide groove H10a by the crown part 1012 and the neck part 1011.

[0083] The two side surfaces of the magnet sheet 20 are respectively provided with a second guide groove H20, and the second guide grooves H20 on the adjacent side surfaces of the two adjacent magnet sheets 20 define a clamping groove, and the crown part 1012 is inserted into the clamping groove along the axial direction of the shaft core 11.

[0084] In this embodiment, the strip-shaped part 101 adopts a combined structure design of the neck part 1011 and the crown part 1012, wherein the neck part 1011 is connected with the shaft stand 10, and the crown part 1012 with larger width is arranged at one end of the neck part 1011 away from the shaft stand 10. The width of the crown part 1012 is greater than that of the neck part 1011, and the stepped structure design forms a recessed area between the crown part 1012 and the neck part 1011, that is, the first guide groove H10a is formed. This structure design makes the cross-sectional shape of each strip-shaped part 101 similar to a "T" shape.

[0085] Correspondingly, a second guide groove H20 is arranged on each side surface of the magnet piece 20, and the second guide grooves H20 on the adjacent side surfaces of the adjacent two magnet pieces 20 combine to form a clamping groove. The size and shape of the clamping groove are matched with the crown 1012 of the strip-shaped part 101, so that the crown 1012 can be inserted into the clamping groove in the axial direction. In this way, on the one hand, the strip-shaped part 101 is accommodated by the first guide groove H10a to the edge of the magnet piece 20; on the other hand, the magnet piece 20 reversely covers the crown 1012 of the strip-shaped part 101 through the clamping groove, so that a more reliable fixing effect is achieved, and the accurate positioning of the magnet piece 20 can be ensured during assembly, and the assembly precision and efficiency are improved. In addition, due to the adoption of the double interlocking mode, the structural stability of the rotor assembly under high-speed operation and external impact is significantly improved, and the service life of the product is further prolonged.

[0086] Preferably, the magnet piece 20 is a tile-shaped magnet, and the shaft support 10 is made of a magnetic conductive material and is formed in a cylindrical structure. That is, the shape of the magnet piece 20 presents an arc-shaped cross section, and the arc-shaped design is matched with the shape of the outer surface of the cylindrical shaft support 10. The inner arc surface of the tile-shaped magnet is well fitted with the outer cylindrical surface of the shaft support 10, and the outer arc surface constitutes the cylindrical outer surface of the whole rotor assembly. The tile-shaped structure not only ensures the matching precision between the magnet piece 20 and the shaft support 10, but also ensures that the rotor assembly has a regular cylindrical shape. The shaft support 10 is made of a magnetic conductive material and is designed in a cylindrical structure. The magnetic conductive material can provide a good magnetic conductive channel for the magnetic circuit and enhance the magnetic field strength. The cylindrical structure provides a forming basis for the cylindrical shape of the tile-shaped magnet, and facilitates the rotational movement of the rotor assembly. At the same time, compared with the rotor assembly with a rectangular structure, the rotor assembly with a cylindrical structure has a larger rotation angle and torque.

[0087] Referring to Figure 6 and Figure 7 It is shown that the acoustic motor according to the embodiment of the utility model, including shell 30, stator core 40, coil 50 and the rotor assembly as described above.

[0088] The stator core 40 is fixed in the shell 30, and the stator core 40 has two radially opposite stator teeth 401, and the opposite inner side surfaces of the two stator teeth 401 are arc surfaces S40.

[0089] The coil 50 is wound on the stator tooth 401 to generate a magnetic field. The rotor assembly is arranged in the shell 30 and located between the two arc surfaces S40 to reciprocate under the drive of the magnetic field. One end of the shaft core 11 of the rotor assembly can be connected to a driving shaft 111, and the driving shaft 111 is convenient to connect target components such as toothbrush heads to realize the driving of the target components.

[0090] According to the acoustic motor provided by the embodiment of the utility model, a plurality of slots are arranged on the outer surface of the shaft support 10 along the circumference of the shaft core 11 in the rotor assembly, and the magnet piece 20 is matched with the slot through axial insertion, so that the insertion type fixing method has higher mechanical strength and reliability compared with the traditional adhesive method, effectively prevents the magnet piece 20 from separating from the shaft support 10 when falling or vibrating, can pass more strict falling test, and significantly improves the product reliability and service life.

[0091] In the description of the present specification, the description of the terms "one embodiment", "some embodiments", "example", "specific example" or "some examples" and the like means that the specific features, structures, materials or characteristics described in connection with the embodiment or example are included in at least one embodiment or example of the utility model. In the present specification, the illustrative description of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any one or more embodiments or examples in a suitable manner. In addition, the skilled in the art can combine and combine the different embodiments or examples described in the present specification and the features of the different embodiments or examples without contradiction.

[0092] The above is only the preferred embodiment of the utility model, and does not limit the patent range of the utility model, and any equivalent structural transformation made by the utility model specification and the attached drawings, or direct / indirect application in other related technical fields under the utility model concept of the utility model is included in the patent protection range of the utility model.

Claims

1. A rotor assembly characterized by, The application relates to a rotor assembly. The rotor assembly comprises: a shaft support, the shaft support is provided with a shaft core in the center, and the outer surface of the shaft support is provided with at least two insertion grooves, the at least two insertion grooves are arranged at intervals in the circumferential direction of the shaft core, and each insertion groove extends along the axis of the shaft core; 2. The rotor assembly of claim 1, wherein at least two magnet pieces, the at least two magnet pieces correspond to the at least two insertion grooves one by one, each magnet piece is inserted into the insertion groove along the axial direction of the shaft core, so that the magnet piece is fixed on the shaft support.

3. The rotor assembly of claim 2, wherein, The magnet pieces and the insertion grooves are four in number. Two magnet pieces in the four magnet pieces form a magnet group, and two magnet groups are symmetrical about an axial plane, the axial plane coincides with the axis of the shaft core.

4. The rotor assembly of claim 3, wherein The magnetization direction of one magnet piece in each magnet group is radial magnetization, and the south pole is located on the radial outer side; the magnetization direction of the other magnet piece in each magnet group is radial magnetization, and the north pole is located on the radial outer side. The outer surface of the shaft support is provided with four strip-shaped parts, the four strip-shaped parts are arranged at intervals in the circumferential direction of the shaft core; 5. The rotor assembly of claim 4, wherein each strip-shaped part extends along the axial direction of the shaft core, and two opposite side faces of each strip-shaped part are respectively provided with a first guide groove extending along the length direction of the strip-shaped part; the first guide grooves on the adjacent side faces of the adjacent two strip-shaped parts define the insertion grooves.

6. The rotor assembly of claim 5, wherein, The widths of the adjacent two strip-shaped parts are different, and the widths of the two strip-shaped parts opposite in the radial direction are the same, the strip-shaped part with the larger width in the adjacent two strip-shaped parts is symmetrical about the axial plane.

7. The rotor assembly of claim 6, wherein The outer face of the strip-shaped part with the larger width in the adjacent two strip-shaped parts has a protruding part protruding outward in the radial direction.

8. The rotor assembly of claim 6, wherein The middle of the width direction of the protruding part is provided with a groove extending along the length direction of the strip-shaped part. The strip-shaped part comprises a neck part and a crown part, the crown part is arranged on the end of the neck part away from the shaft support, and the width of the crown part is greater than that of the neck part, so that the first guide groove is defined by the crown part and the neck part; 9. The rotor assembly of claim 6, wherein, the two side faces of the magnet piece are respectively provided with a second guide groove, the second guide grooves on the adjacent side faces of the adjacent two magnet pieces define a clamping groove, and the crown part is inserted into the clamping groove along the axial direction of the shaft core.

10. An acoustic wave motor characterized by The magnet piece is a tile-shaped magnet, the shaft support is made of a magnetic conductive material and has a cylindrical structure. The application relates to a rotor assembly. The rotor assembly comprises: a shell; a stator core, the stator core is fixed in the shell, and the stator core has two radially opposite stator teeth, and the opposite inner side faces of the two stator teeth are arc faces; a coil, the coil is wound on the stator teeth and is used for generating a magnetic field; the rotor assembly is arranged in the shell and between the two arc faces, and is used for reciprocating vibration under the driving of the magnetic field.

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