Rotor assembly and servo motor

Abstract

The application discloses a rotor assembly and a servo motor, wherein the rotor assembly comprises a first rotor lamination, a second rotor lamination and a magnetic steel; the first rotor lamination is provided with a plurality of magnetic steel grooves which are arranged at intervals in the circumferential direction, and a pole shoe is formed between the magnetic steel groove and the outer side wall of the first rotor lamination; the axial projection of the second rotor lamination on the first rotor lamination is a first projection, and the magnetic steel groove and at least part of the pole shoe are located outside the first projection; at least part of the magnetic steel is arranged in the magnetic steel groove; wherein a plurality of first rotor laminations are arranged in layers to form a rotor body part, and a plurality of second rotor laminations are arranged in layers to form an inertia part. In the application, part of each pole shoe of the rotor body part is located outside the inertia part, the shielding of the end part of the pole shoe by the inertia part is reduced, and the risk of magnetic flux leakage caused by the axial overlap of the inertia part and the pole shoe structure is reduced. The rotor body part and the inertia part can be formed by one-time stacking and pressing, which is beneficial to simplifying the manufacturing process and improving the production efficiency.

Description

Technical Field

[0001] This invention relates to the field of motor technology, specifically to a rotor assembly and a servo motor. Background Technology

[0002] In related technologies, built-in permanent magnet motors have slotted rotor laminations and magnets placed in the rotor core composed of the rotor laminations, thereby achieving higher rotor strength, greater air gap magnetic flux density, and improved motor power density. However, in some fields with special requirements for motor rotational inertia, such as servo motors, adjusting the inertia solely by adjusting the axial length of the rotor core may cause serious axial magnetic leakage problems, reducing motor performance. Summary of the Invention

[0003] This invention aims to at least solve one of the technical problems existing in the prior art. To this end, this invention proposes a rotor assembly and a servo motor that can reduce axial leakage flux while meeting the requirements of rotational inertia, thereby improving motor performance.

[0004] In a first aspect, embodiments of the present invention provide a rotor assembly, comprising: a first rotor lamination having a plurality of circumferentially spaced magnetic slots, wherein the magnetic slots form pole shoes between the magnetic slots and the outer sidewall of the first rotor lamination; a second rotor lamination having a first projection on the axial direction of the second rotor lamination, wherein the magnetic slots and at least a portion of the pole shoes are located outside the first projection; and magnets having at least a portion of the magnets disposed within the magnetic slots; wherein the plurality of first rotor laminations are stacked to form a rotor body portion, and the plurality of second rotor laminations are stacked to form an inertia portion, wherein the inertia portion is located at at least one end of the rotor body portion.

[0005] The rotor assembly according to embodiments of the present invention has at least the following beneficial effects: the rotor assembly adjusts the rotational inertia of the entire rotor assembly by forming an inertia section through the stacking of second rotor laminations. Both the rotor body and the inertia section are formed by stacking rotor laminations, meaning they can be formed in a single stacking process, eliminating the need to manufacture and assemble them as two separate components, thus simplifying the manufacturing process and improving production efficiency. Since the magnet slots are fully exposed in the first projection, each pole shoe is at least partially exposed in the projection area formed by the inertia section, meaning each pole shoe is partially located outside the inertia section. This reduces the obstruction of the pole shoe ends by the inertia section and lowers the risk of end magnetic leakage caused by the axial overlap of the inertia section and pole shoe structure.

[0006] According to some embodiments of the present invention, the first rotor lamination includes a first yoke located radially inside the magnet slot; the second rotor lamination includes a second yoke, the second yoke overlapping at least partially with the first yoke.

[0007] According to some embodiments of the present invention, the first rotor lamination includes a magnetic isolation bridge located between two adjacent magnet slots, the magnetic isolation bridge being connected to the first yoke; the second rotor lamination includes a toothed portion connected to the outer wall of the second yoke, the toothed portion overlapping at least partially with the magnetic isolation bridge.

[0008] According to some embodiments of the present invention, the second rotor lamination is formed by the first rotor lamination breaking off the pole shoe and at least partially breaking off the magnetic bridge or breaking off the pole shoe.

[0009] According to some embodiments of the present invention, the maximum outer radius of the first rotor lamination is R1, and the maximum distance between the outer wall of the second rotor lamination and the shaft center is D. 2max Where R1 / 3 < D 2max <R1.

[0010] According to some embodiments of the present invention, the number of pole shoes is twice the number of pole pairs of the rotor assembly, and the number of magnet slots is K times the number of pole shoes, where K is a positive integer.

[0011] According to some embodiments of the present invention, the magnet slot is elongated, and a magnetic bridge is formed between the ends of two adjacent magnet slots; or, an auxiliary slot is provided on the outer wall of the first rotor lamination, and the auxiliary slot is located between two adjacent magnet slots; the magnetic bridge is formed between the ends of two adjacent magnet slots and the wall of the auxiliary slot.

[0012] According to some embodiments of the present invention, the magnetic steel groove includes a first groove body and a second groove body that are at an included angle to each other, the radial inner ends of the first groove body and the radial outer ends of the second groove body are close to each other and far apart from each other; in two adjacent magnetic steel grooves, a magnetic isolation bridge is formed between the radial outer ends of the first groove body of one magnetic steel groove and the second groove body of the other magnetic steel groove; the radial inner ends of the first groove body and the second groove body are connected, or the first groove body and the second groove body are separated by the magnetic isolation bridge.

[0013] According to some embodiments of the present invention, the magnetic steel groove includes a third groove, a fourth groove, and a fifth groove, the third groove and the fourth groove extending radially and spaced apart circumferentially, the fifth groove communicating with the radially inner end of the third groove and the radially inner end of the fourth groove; in two adjacent magnetic steel grooves, a magnetic isolation bridge is formed between one of the third grooves and the fourth groove of the other magnetic steel groove; or,

[0014] The plurality of magnetic slots include a plurality of first magnetic slots and a plurality of second magnetic slots. The plurality of first magnetic slots are arranged radially along the first rotor lamination. A second magnetic slot is provided between the radial inner ends of two adjacent first magnetic slots. The two ends of the second magnetic slot and the two adjacent first magnetic slots respectively form the magnetic isolation bridge.

[0015] According to some embodiments of the present invention, the magnet slot is an arc-shaped slot protruding toward the axis of the first rotor lamination, and the magnetic bridge is formed between the inner sidewalls of two adjacent arc-shaped slots.

[0016] According to some embodiments of the present invention, along the axial direction, the end of the magnet protrudes beyond the end of the rotor body; or, the end of the magnet is flush with the end of the rotor body; or, the end of the magnet is located within the magnet slot, the distance between the end of the magnet and the end of the rotor body is A, and the thickness of the first rotor lamination is h, where A≤2h.

[0017] According to some embodiments of the present invention, the first rotor lamination has a first shaft hole, the second rotor lamination has a second shaft hole, and the first shaft hole and the second shaft hole coincide along the axial direction.

[0018] Secondly, embodiments of the present invention also provide a servo motor, the servo motor including the rotor assembly described in the first aspect.

[0019] The motor according to embodiments of the present invention has at least the following beneficial effects: the rotor assembly adjusts the rotational inertia of the entire rotor assembly by forming an inertia section through the stacking of second rotor laminations. Both the rotor body and the inertia section are formed by stacking rotor laminations, meaning they can be formed in a single stacking process, eliminating the need to manufacture and assemble them as two separate components, thus simplifying the manufacturing process and improving production efficiency. Since the magnet slots are fully exposed in the first projection, each pole shoe is at least partially exposed in the projection area formed by the inertia section, meaning each pole shoe is partially located outside the inertia section. This reduces the obstruction of the pole shoe ends by the inertia section and lowers the risk of end magnetic leakage caused by the axial overlap of the inertia section and pole shoe structure.

[0020] Additional aspects and advantages of the invention will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. Attached Figure Description

[0021] The present invention will be further described below with reference to the accompanying drawings and embodiments, wherein:

[0022] Figure 1 This is a schematic diagram of the rotor assembly in an embodiment of the present invention;

[0023] Figure 2 This is a schematic diagram of the rotor body in an embodiment of the present invention;

[0024] Figure 3 This is a schematic diagram of the inertia unit in an embodiment of the present invention;

[0025] Figure 4 This is a schematic diagram of the inertia unit in an embodiment of the present invention;

[0026] Figure 5 This is a schematic diagram of the structure of the first rotor lamination in the first embodiment of the present invention;

[0027] Figure 6 This is a schematic diagram of the structure of the second rotor lamination in the first embodiment of the present invention;

[0028] Figure 7 This is a schematic diagram of the structure of the first rotor lamination in the second embodiment of the present invention;

[0029] Figure 8 This is a schematic diagram of the structure of the second rotor lamination in the second embodiment of the present invention;

[0030] Figure 9 This is a schematic diagram of the structure of the first rotor lamination in the third embodiment of the present invention;

[0031] Figure 10 This is a schematic diagram of the structure of the second rotor lamination in the third embodiment of the present invention;

[0032] Figure 11 This is a schematic diagram of the structure of the first rotor lamination in the fourth embodiment of the present invention;

[0033] Figure 12 This is a schematic diagram of the structure of the second rotor lamination in the fourth embodiment of the present invention;

[0034] Figure 13 This is a schematic diagram of the structure of the first rotor lamination in the fifth embodiment of the present invention;

[0035] Figure 14 This is a schematic diagram of the structure of the second rotor lamination in the fifth embodiment of the present invention;

[0036] Figure 15 This is a schematic diagram of the structure of the first rotor lamination in the sixth embodiment of the present invention;

[0037] Figure 16 This is a schematic diagram of the structure of the second rotor lamination in the sixth embodiment of the present invention;

[0038] Figure 17 This is a schematic diagram of the structure of the first rotor lamination in the seventh embodiment of the present invention;

[0039] Figure 18This is a schematic diagram of the structure of the second rotor lamination in the seventh embodiment of the present invention;

[0040] Figure 19 This is a schematic diagram of the structure of the first rotor lamination in the eighth embodiment of the present invention;

[0041] Figure 20 This is a schematic diagram of the structure of the second rotor lamination in the eighth embodiment of the present invention;

[0042] Figure 21 This is a comparison between a magnetic field simulation diagram of the rotor assembly applied to a motor in the first embodiment of the present invention and a magnetic field simulation diagram of the prior art.

[0043] Figure label:

[0044] 100. Rotor assembly;

[0045] 110. First rotor lamination; 110a. Rotor body; 111. Magnet slot; 1111. First slot; 1112. Second slot; 1113. Third slot; 1114. Fourth slot; 1115. Fifth slot; 111a. First magnet slot; 111b. Second magnet slot; 112. Pole shoe; 113. First yoke; 114. Magnetic bridge; 115. First shaft hole; Auxiliary slot; 116.

[0046] 120. Second rotor lamination; 120a. Inertia section; 121. Second yoke section; 122. Tooth section; 123. Second shaft hole;

[0047] 130. Magnet steel;

[0048] 200. Stator assembly. Detailed Implementation

[0049] Embodiments of the present invention are described in detail below. Examples of these embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present invention, and should not be construed as limiting the present invention.

[0050] In the description of this invention, it should be understood that the orientation descriptions, such as up, down, front, back, left, right, etc., are based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limiting this invention.

[0051] In the description of this invention, "several" means one or more, "multiple" means two or more, "greater than," "less than," and "exceeding" are understood to exclude the stated number, while "above," "below," and "within" are understood to include the stated number. The use of "first" and "second" in the description is merely for distinguishing technical features and should not be construed as indicating or implying relative importance, or implicitly indicating the number of indicated technical features, or implicitly indicating the order of the indicated technical features.

[0052] In the description of this invention, unless otherwise explicitly defined, terms such as "set up," "install," and "connect" should be interpreted broadly, and those skilled in the art can reasonably determine the specific meaning of the above terms in this invention in conjunction with the specific content of the technical solution.

[0053] In the description of this invention, the terms "one embodiment," "some embodiments," "illustrative embodiment," "example," "specific example," or "some examples," etc., refer to specific features, structures, materials, or characteristics described in connection with that embodiment or example, which are included in at least one embodiment or example of the invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0054] The embodiments of the present invention will be further described below with reference to the accompanying drawings.

[0055] like Figures 1 to 3 , Figure 5 and Figure 6 As shown, the rotor assembly 100 includes a rotor body portion 110a formed by stacking first rotor laminations 110, an inertia portion 120a formed by stacking second rotor laminations 120, and a magnet 130.

[0056] The first rotor lamination 110 is provided with a plurality of circumferentially spaced magnetic slots 111, and pole shoes 112 are formed between the magnetic slots 111 and the outer sidewall of the first rotor lamination 110. The first rotor laminations 110 are stacked to form a rotor body portion 110a. The magnetic slots 111 of the plurality of first rotor laminations 110 are axially connected and used to install magnets 130, forming a magnetic field acting on the stator portion of the motor.

[0057] The inertia section 120a is connected to at least one end of the rotor body section 110a and is used to adjust the rotational inertia. The axial projection of the second rotor lamination 120 onto the first rotor lamination 110 is the first projection. The magnet slots 111 and at least part of the pole shoes 112 of the first rotor lamination 110 are located outside the first projection; that is, the second rotor lamination 120 does not completely cover the pole shoes 112, but leaves a certain space so that part or all of the pole shoes 112 are exposed.

[0058] In this embodiment, the magnet slot 111 is fully exposed in the first projection, and part or all of the pole shoe 112 is exposed in the first projection. This can reduce the obstruction of the pole shoe 112 by the inertia part 120a, thereby reducing the risk of magnetic leakage caused by the axial structural overlap between the inertia part 120a and the pole shoe 112. Furthermore, the electromagnetic and rotational inertia are decoupled by the rotor body part 110a and the inertia part 120a, which facilitates the optimization of the rotor body part 110a and the inertia part 120a respectively, thereby meeting different application requirements.

[0059] Furthermore, the second rotor lamination 120 located at the end of the end inertia portion 120a can be directly connected to the first rotor lamination 110 located at the end of the rotor body portion 110a. That is, the rotor body portion 110a and the inertia portion 120a can be formed by one stacking, without having to manufacture and assemble the rotor body portion 110a and the inertia portion 120a as two independent components, which simplifies the manufacturing process and improves production efficiency.

[0060] The connection between the rotor body 110a and the inertia section 120a is tighter, reducing gaps or loosening caused by improper assembly. This tight connection helps improve the overall rigidity and stability of the rotor assembly 100, thereby improving the performance and reliability of the motor.

[0061] The first rotor lamination 110 and the adjacent second rotor lamination 120 can be fixed together by riveting, bonding, welding, or snap-fit ​​connections, thereby achieving a tight connection between the rotor body 110a and the inertia part 120a, forming a whole. In terms of material selection, the first rotor lamination 110 and the second rotor lamination 120 can be made of materials with high magnetic permeability, such as silicon steel, molybdenum steel, or nickel-iron alloy, thereby effectively reducing the iron loss of the motor and improving motor performance. It should be noted that the above connection methods and material selections are merely examples, and this embodiment does not limit them.

[0062] For ease of description, the orientation descriptions below are based on the rotor assembly 100, that is, the axial, circumferential and radial directions mentioned below refer to the axial, circumferential and radial directions of the rotor assembly 100, respectively.

[0063] In some embodiments, in order to further reduce the influence of the inertia section 120a on the electromagnetic effect, the second rotor lamination 120 can be configured such that the pole shoe 112 and the magnet slot 111 are completely exposed on the outer side wall of the second rotor lamination 120.

[0064] The number of inertia sections 120a can be one or two. When there is only one inertia section 120a, it is connected to one end of the rotor body section 110a along the axial direction. When there are two inertia sections 120a, one inertia section 120a is connected to each end of the rotor body section 110a along the axial direction. The two inertia sections 120a can have the same axial length and the same cross-sectional shape perpendicular to the axial direction, which helps to maintain the axial symmetry of the motor and further improve the balance and stability of the motor. This improves the axial balance of the motor and reduces vibration and noise.

[0065] To optimize the motor's moment of inertia, heat dissipation performance, or to meet specific installation requirements, the axial lengths of the two inertia sections 120a can be set to be different. The axial length of the inertia section 120a can be flexibly adjusted by changing the number of stacked second rotor laminations 120. The shapes of the two inertia sections 120a along the cross-section perpendicular to the axial direction can also be different. This embodiment does not limit this.

[0066] In some embodiments, the first rotor lamination 110 includes a first yoke 113 and a magnetic bridge 114. The first yoke 113 is located radially inside the magnet slot 111, and the magnetic bridge 114 is located between two adjacent magnet slots 111, and the magnetic bridge 114 is connected to the first yoke 113.

[0067] The first yoke 113 provides a stable support for the magnet 130 and the pole shoe 112. Saturation of the magnetic flux in the magnetic isolation bridge 114 limits magnetic leakage, improves the utilization rate of the magnet 130, and thus enhances the efficiency and performance of the motor. The design of the magnetic isolation bridge 114 can also optimize the electromagnetic performance of the motor. By adjusting parameters such as the thickness, shape, and material of the magnetic isolation bridge 114, the magnetic circuit distribution and magnetic field strength of the motor can be affected, thereby adjusting performance indicators such as electromagnetic torque, efficiency, and power factor. This makes the motor design more flexible and meets the needs of different application scenarios.

[0068] The second rotor lamination 120 includes a second yoke 121, which overlaps with at least a portion of the first yoke 113. That is, the second rotor lamination 120 can be a ring structure, and the radial dimension of the second rotor lamination 120 is generally smaller than the radial dimension of the first rotor lamination 110. Figure 3 As shown, the outer sidewall of the second rotor lamination 120 can coincide with the radial inner sidewall of the magnet slot 111 in the first rotor lamination 110. While ensuring that the second rotor lamination 120 does not block the magnet slot 111 and reducing the risk of end magnetic leakage, the radial space of the first rotor lamination 110 is fully utilized, which is conducive to providing a larger moment of inertia in a limited axial space.

[0069] In this case, the outer wall shape of the second rotor lamination 120 tends to be polygonal, and the polygonal structure is formed by the intersection of the inner edges of the adjacent magnet slots 111. The vertices of the polygonal structure can be rounded or chamfered to improve the overall smoothness.

[0070] The outer wall of the second rotor lamination 120 can be designed as a standard circle. The standard circle outer wall simplifies the edge shape of the inertia section 120a. At the same time, the circular structure has better balance and stability when rotating, which helps to reduce vibration and noise and improve the overall performance of the motor.

[0071] Furthermore, such as Figure 4 As shown, the second rotor lamination 120 also includes teeth 122 connected to the outer wall of the second yoke 121, and the teeth 122 coincide with at least a portion of the magnetic isolation bridge 114. The teeth 122 can further increase the moment of inertia provided by the second rotor lamination 120. The structure of the second rotor lamination 120 can fit tightly around the magnet slot 111, thereby improving the overall integrity and stability of the structure. By cleverly utilizing the space between the magnet slot 111 and the magnetic isolation bridge 114, the design achieves the goal of maximizing the moment of inertia within a limited space.

[0072] Based on this, the second rotor lamination 120 overlaps with the first rotor lamination 110 in most areas, differing only in the radial dimensions or shape of the outer walls. Therefore, the rotor laminations can be stamped from silicon steel sheets into the required shapes of the first rotor lamination 110 and the second rotor lamination 120 through a first-stage stamping process and a second-stage stamping process. In this application, the rotor lamination that has completed the first-stage stamping process is the first rotor lamination 110, and the rotor lamination that has completed the second-stage stamping process based on the first rotor lamination 110 is the second rotor lamination 120. This only requires adding a stamping step to the existing rotor lamination processing line or adjusting the existing stamping dies, which is highly flexible and cost-effective, and can quickly adapt to the production needs of rotor laminations of different models or specifications.

[0073] It should be noted that the first stage of stamping can also go through multiple stamping stations and dies, and the second stage of stamping can also go through multiple stamping stations and dies. This embodiment does not limit this.

[0074] The second rotor lamination 120 is formed by breaking the pole shoe 112 and at least part of the magnetic isolation bridge 114 or breaking the pole shoe 112 of the first rotor lamination 110. That is, based on the first rotor lamination 110, the second stage of stamping is performed at the pole shoe 112 or the magnetic isolation bridge 114.

[0075] The first rotor lamination 110 has a first shaft hole 115, which can serve as the mounting position for the motor shaft; the second rotor lamination 120 has a second shaft hole 123, which is axially aligned with and communicates with the first shaft hole 115; the motor shaft is tightly fitted with the first shaft hole 115, so that the motor shaft is stably fixed to the rotor assembly 100, and the motor shaft can pass through the second shaft hole 123.

[0076] The diameter of the second shaft hole 123 can be the same as that of the first shaft hole 115, that is, the first shaft hole 115 and the second shaft hole 123 coincide axially, together forming a mounting hole for mounting the motor shaft. This increases the contact length between the rotor assembly 100 and the motor shaft, which is beneficial for the motor shaft to maintain a stable alignment. The diameter of the second shaft hole 123 can also be larger than that of the first shaft hole 115, which can facilitate the motor shaft to pass through the second shaft hole 123. This embodiment does not limit this.

[0077] To optimize the dynamic performance of the rotor assembly 100 or meet specific rotor magnetic field requirements, the outer wall of the first rotor lamination 110 can be designed as a non-standard circle. In this embodiment, the maximum outer radius R of the first rotor lamination 110 is used as the standard. The distance between the outer wall of the second rotor lamination 120 and the axis of the rotor assembly 100 represents the radial extension length of the second rotor lamination 120. The larger the radial extension length of the second rotor lamination 120, the greater the moment of inertia provided by the second rotor lamination 120. Moment of inertia is the inertial quantity that allows an object to maintain a constant angular velocity while rotating. Rotation is related to the mass distribution and radius of rotation of the object. Therefore, by adjusting the radial extension length of the second rotor lamination 120, the additional moment of inertia provided by the second rotor lamination 120 can be controlled to meet specific performance requirements.

[0078] In this embodiment, the maximum distance Dmax between the outer wall of the second rotor lamination 120 and the axis of the rotor assembly 100 is used as the metric, where R1 / 3 < Dmax < R1. By controlling the maximum radial extension length of the second rotor lamination 120 within this range, the radial extension length of the second rotor lamination 120 is neither too large to obstruct the magnet slot 111 and pole shoe 112, nor too small to provide sufficient rotational inertia.

[0079] Based on the above embodiments, the first rotor lamination 110 and the second rotor lamination 120 can have counterweight holes (not shown). By opening the counterweight holes, the mass distribution of the rotor assembly 100 can be adjusted, and the moment of inertia of the rotor assembly 100 can be further fine-tuned to meet specific performance requirements and cope with different working conditions and load requirements.

[0080] The rotor body 110a may also include other types of laminations, such as reinforcing laminations, which can increase the mechanical strength of the rotor body 110a and can be located at key locations in the rotor body 110a, such as around the magnet slots 111 or in stress concentration areas of the rotor; ventilation laminations, which are designed with ventilation holes or ventilation slots to improve the heat dissipation performance of the rotor assembly 100; and balancing laminations, which are used to adjust the mass distribution of the rotor to achieve better rotational balance. In specific implementations, one or more laminations can be used in conjunction with the first rotor lamination 110 to form the rotor body 110a, but this embodiment does not limit this.

[0081] In some embodiments, the number of pole shoes 112 is twice the number of pole pairs of rotor assembly 100, and the number of magnet slots 111 is K times the number of pole shoes 112, where K is a positive integer.

[0082] The magnet slot 111 can be a single slot or a group of slots. Typically, a group of slots forms a pole piece 112. In this embodiment, the relationship between the number of slots and the number of pole pieces 112 is discussed. The number of slots is M times the number of pole pieces 112, where M is a positive integer.

[0083] The first rotor lamination 110 and the second rotor lamination 120 with different compositions of the magnet slot 111 are described below by way of examples.

[0084] In the first embodiment, the first rotor lamination 110 is as follows: Figure 5 As shown, the magnetic steel groove 111 is elongated, and a magnetic isolation bridge 114 is formed between the ends of two adjacent magnetic steel grooves 111. The radial inner side of the magnetic steel groove 111 is the first yoke 113, and the radial outer side of the magnetic steel groove 111 is the pole shoe 112.

[0085] The second rotor lamination 120, as shown Figure 6 As shown, the shape of the second rotor lamination 120 matches the shape of the first yoke portion 113 of the first rotor lamination 110. Please refer to [link / reference]. Figure 5 , Figure 5 The dashed line L1 indicates the breakage position of the first rotor lamination 110, not the structure on the first rotor lamination 110; the length of the dashed line L1 is only to clearly show the relationship between the breakage position and the magnetic isolation bridge 114, not to indicate the breakage length. That is, the second rotor lamination 120 can be obtained by breaking the magnetic isolation bridge 114 along the position of the dashed line L1 based on the first rotor lamination 110, with the breakage position located at the radial inner end of the magnetic isolation bridge 114.

[0086] The second rotor lamination 120 is based on the first rotor lamination 110 but removes all the structures of the pole shoe 112 and the magnetic bridge 114. The second rotor lamination 120 can be completely covered by the first rotor lamination 110.

[0087] like Figure 6 As shown, edge a of the second rotor lamination 120 corresponds to the inner edge of the magnet slot 111 on the first rotor lamination 110, and edge b of the second rotor lamination 120 is formed by the break-off position.

[0088] The first rotor laminations 110 are stacked to form the rotor body 110a, which includes 10 magnet slots 111 and 10 pole shoes 112. Each magnet slot 111 includes a strip-shaped groove. The number of magnet slots 111 is equal to the number of pole shoes 112, K=1; the number of slots is equal to the number of pole shoes 112, M=1; when the magnets 130 are installed in the slots, the number of rotor pole pairs is 5, and the number of pole shoes 112 is twice the number of rotor pole pairs.

[0089] In the second embodiment, the first rotor lamination 110 is as follows: Figure 7 As shown, the second rotor lamination 120 is as follows Figure 8 As shown; the first rotor lamination 110 in the second embodiment has the same structure as the first rotor lamination 110 in the first embodiment. The only difference between the second embodiment and the first embodiment is that the shape of the second rotor lamination 120 matches the shape of the first yoke 113 and the magnetic isolation bridge 114 of the first rotor lamination 110. Please refer to Figure 7 , Figure 7 The dashed line L1 indicates the breakage position of the first rotor lamination 110, not the structure on the first rotor lamination 110; the length of the dashed line L1 is only to clearly show the relationship between the breakage position and the magnetic isolation bridge 114, not to indicate the breakage length. That is, the second rotor lamination 120 can be obtained by breaking the magnetic isolation bridge 114 along the position of the dashed line L1 based on the first rotor lamination 110, with the breakage position located at the end of the magnetic isolation bridge 114 away from the center of the first rotor lamination 110.

[0090] The second rotor lamination 120 removes all the structure of the pole shoe 112 from the first rotor lamination 110, and the second rotor lamination 120 can be completely covered by the first rotor lamination 110.

[0091] like Figure 8 As shown, edge a of the second rotor lamination 120 corresponds to the inner radial edge of the magnet slot 111 on the first rotor lamination 110, and edge b of the second rotor lamination 120 is formed by the break-off position.

[0092] In the third embodiment, the first rotor lamination 110 is as follows: Figure 9 As shown, the second rotor lamination 120 is as follows Figure 10As shown; the difference between the third embodiment and the first embodiment is that: an auxiliary groove is provided on the outer side wall of the first rotor lamination 110, and the auxiliary groove is located between two magnet slots 111. Between two adjacent magnet slots 111, a magnetic isolation bridge 114 is formed between the end of the two adjacent magnet slots 111 and the auxiliary groove, thereby the first rotor lamination 110 has a magnetic isolation bridge 114.

[0093] Please refer to the figure. Figure 9 The dashed lines L1 and L2 indicate the breakage positions of the first rotor lamination 110, not the structure on the first rotor lamination 110; the lengths of the dashed lines L1 and L2 are only to clearly show the relationship between the breakage position and the magnetic isolation bridge 114, not to represent the breakage length. That is, the second rotor lamination 120 can be obtained by breaking the magnetic isolation bridge 114 along the positions of the dashed lines L1 and L2 based on the first rotor lamination 110. The breakage position is located on the extension line of the inner edge of the magnetic slot 111 of the first rotor lamination 110.

[0094] like Figure 10 As shown, edge a of the second rotor lamination 120 corresponds to the inner edge and the break-off position of the magnet groove 111 on the first rotor lamination 110, and edge c of the second rotor lamination 120 corresponds to the groove edge of the first rotor lamination 110.

[0095] In the fourth embodiment, the first rotor lamination 110 is as follows: Figure 11 As shown, the second rotor lamination 120 is as follows Figure 12 As shown; the difference between the fourth embodiment and the first embodiment is that: in the first rotor lamination 110, two slots form a magnetic slot 111, that is, the magnetic slot 111 includes a first slot 1111 and a second slot 1112. The first slot 1111 and the second slot 1112 of the same magnetic slot 111 are arranged in a V-shape, that is, the radial inner ends of the first slot 1111 and the second slot 1112 are close to each other and connected, while the radial outer ends are far apart from each other; in two adjacent magnetic slots 111, a magnetic bridge 114 is formed between the radial outer ends of the first slot 1111 of one magnetic slot 111 and the second slot 1112 of the other magnetic slot 111.

[0096] Please see Figure 11 , Figure 11 The dashed line L1 indicates the breakage position of the first rotor lamination 110, not the structure on the first rotor lamination 110; the length of the dashed line L1 is only to clearly show the relationship between the breakage position and the magnetic isolation bridge 114, not to indicate the breakage length. That is, the second rotor lamination 120 can be obtained by breaking the magnetic isolation bridge 114 along the position of the dashed line L1 based on the first rotor lamination 110, with the breakage position located at the radial inner end of the magnetic isolation bridge 114.

[0097] like Figure 12As shown, edge a of the second rotor lamination 120 corresponds to the inner edge of the magnet slot 111 on the first rotor lamination 110, and edge b of the second rotor lamination 120 corresponds to the break-off position.

[0098] The first rotor laminations 110 are stacked to form the rotor body 110a, which includes 10 magnet slots 111 and 10 pole shoes 112. Each magnet slot 111 includes 2 slot bodies. The number of magnet slots 111 is equal to the number of pole shoes 112, K=1. The number of slot bodies is twice the number of pole shoes 112, M=2. When the magnets 130 are installed in the magnet slots 111, the number of rotor pole pairs is 5, and the number of pole shoes 112 is twice the number of rotor pole pairs.

[0099] In the fifth embodiment, the first rotor lamination 110 is as follows: Figure 13 As shown, the second rotor lamination 120 is as follows Figure 14 As shown; the difference between the fifth embodiment and the fourth embodiment is that in the first rotor lamination 110, in the same magnetic slot 111, the radial inner end of the first slot 1111 and the radial inner end of the second slot 1112 are not connected to each other. That is, a magnetic bridge 114 is also formed between the radial inner end of the first slot 1111 and the radial inner end of the second slot 1112.

[0100] Please see Figure 13 In the diagram, dashed lines L1 and L2 represent the breakage locations of the first rotor lamination 110, not the structure on the first rotor lamination 110; the lengths of dashed lines L1 and L2 are only to clearly show the relationship between the breakage location and the magnetic isolation bridge 114, and do not represent the breakage length. That is, the second rotor lamination 120 can be obtained by breaking the magnetic isolation bridge 114 along the locations of dashed lines L1 and L2 based on the first rotor lamination 110, with the breakage location located at the radial inner end of the magnetic isolation bridge 114.

[0101] like Figure 14 As shown, edge a of the second rotor lamination 120 corresponds to the inner edge of the magnet slot 111 on the first rotor lamination 110, edge b of the second rotor lamination 120 corresponds to the breakage position shown by the dashed line L1, and edge b of the second rotor lamination 120 corresponds to the breakage position shown by the dashed line L2.

[0102] The first rotor laminations 110 are stacked to form the rotor body 110a, which includes 100 magnet slots 111 and 10 pole shoes 112. Each magnet slot includes 2 slot bodies. The number of magnet slots 111 is equal to the number of pole shoes 112, K=1; the number of slot bodies is twice the number of pole shoes 112, M=2; when magnets 130 are installed in the magnet slots 111, the number of rotor pole pairs is 5, and the number of pole shoes 112 is twice the number of rotor pole pairs.

[0103] In the sixth embodiment, the first rotor lamination 110 is as follows: Figure 15As shown, the second rotor lamination 120 is as follows Figure 16 As shown; the difference between the sixth embodiment and the first embodiment is that: in the first rotor lamination 110, the magnet slot 111 includes three slots, namely, the magnet slot 111 includes a third slot 1113, a fourth slot 1114, and a fifth slot 1115. The third slot 1113 and the fourth slot 1114 extend radially and are spaced apart circumferentially. The fifth slot 1115 connects the radial inner end of the third slot 1113 and the radial inner end of the fourth slot 1114. The three magnet slots of the same magnet slot 111 are arranged in a U-shape, and the opening of the U-shape faces the outer wall of the first rotor lamination 110. In two adjacent magnet slots 111, a magnetic bridge 114 is formed between one of the third slots 1113 and the fourth slot 1114 of the other magnet slot 111.

[0104] Please refer to the figure. Figure 15 The dashed line L1 indicates the breakage position of the first rotor lamination 110, not the structure on the first rotor lamination 110; the length of the dashed line L1 is only to clearly show the relationship between the breakage position and the magnetic isolation bridge 114, not to indicate the breakage length. That is, the second rotor lamination 120 can be obtained by breaking the magnetic isolation bridge 114 along the position of the dashed line L1 based on the first rotor lamination 110, with the breakage position located at the radial inner end of the magnetic isolation bridge 114.

[0105] like Figure 16 As shown, edge a of the second rotor lamination 120 corresponds to the inner edge of the magnet slot 111 on the first rotor lamination 110, and edge b of the second rotor lamination 120 corresponds to the break-off position.

[0106] The first rotor laminations 110 are stacked to form the rotor body 110a, which includes 10 magnet slots and 10 pole shoes 112. Each magnet slot 111 includes 3 slot bodies. The number of magnet slots 111 is equal to the number of pole shoes 112, K=1; the number of slot bodies is 3 times the number of pole shoes 112, M=3; when the magnets 130 are installed in the magnet slots 111, the number of rotor pole pairs is 5, and the number of pole shoes 112 is twice the number of rotor pole pairs.

[0107] In the seventh embodiment, the first rotor lamination 110 is as follows: Figure 17 As shown, the second rotor lamination 120 is as follows Figure 18 As shown; the plurality of magnetic slots 111 include a plurality of first magnetic slots 111a and a plurality of second magnetic slots 111b. The plurality of first magnetic slots 111a are arranged radially along the first rotor lamination 110. A second magnetic slot 111b is provided between the radial inner ends of two adjacent first magnetic slots 111a. The two ends of the second magnetic slot 111b and the two adjacent first magnetic slots 111a respectively form magnetic isolation bridges 114.

[0108] Please see Figure 17In the diagram, the dashed line L1 represents the breakage position of the first rotor lamination 110, not the structure on the first rotor lamination 110; the length of the dashed line L1 is only to clearly show the relationship between the breakage position and the magnetic isolation bridge 114, not to represent the breakage length. That is, the second rotor lamination 120 can be obtained by breaking the magnetic isolation bridge 114 along the position of the dashed line L1 based on the first rotor lamination 110. The breakage position is located on the extension line of the inner edge of the bottom magnetic groove 111.

[0109] like Figure 18 As shown, edge a of the second rotor lamination 120 corresponds to the inner edge and the break-off position of the magnet slot 111 on the first rotor lamination 110.

[0110] The first rotor laminations 110 are stacked to form the rotor body 110a, which includes 20 magnet slots 111 and 10 pole shoes 112. Each magnet slot 111 includes a slot body. The number of magnet slots 111 is twice the number of pole shoes 112, K=2; the number of slot bodies is twice the number of pole shoes 112, M=2; when magnets 130 are installed in the magnet slots 111, the number of rotor pole pairs is 5, and the number of pole shoes 112 is twice the number of rotor pole pairs.

[0111] In the eighth embodiment, the first rotor lamination 110 is as follows: Figure 19 As shown, the second rotor lamination 120 is as follows Figure 20 As shown; the difference between the eighth embodiment and the first embodiment is that the magnetic groove 111 is an arc-shaped groove protruding toward the axis of the first rotor lamination 110, and a magnetic bridge 114 is formed between the inner sidewalls of two adjacent arc-shaped grooves.

[0112] Please see Figure 19 In the diagram, the dashed line L1 represents the breakage position of the first rotor lamination 110, not the structure on the first rotor lamination 110; the length of the dashed line L1 is only to clearly show the relationship between the breakage position and the magnetic isolation bridge 114, not to represent the breakage length. That is, the second rotor lamination 120 can be obtained by breaking the magnetic isolation bridge 114 along the position of the dashed line L1 based on the first rotor lamination 110. The breakage position is close to the radial outer end of the magnetic isolation bridge 114, but still some distance away from the radial outer end of the magnetic isolation bridge 114.

[0113] like Figure 20 As shown, edge a of the second rotor lamination 120 corresponds to the inner edge of the magnet slot 111 on the first rotor lamination 110, and edge b of the second rotor lamination 120 corresponds to the break-off position.

[0114] The first rotor laminations 110 are stacked to form the rotor body 110a, which includes four magnet slots 111 and four pole shoes 112. Each magnet slot includes one arc-shaped slot body. The number of magnet slots 111 is equal to the number of pole shoes 112, K=1; the number of slot bodies is equal to the number of pole shoes 112, M=1; when the magnets 130 are installed in the magnet slots 111, the number of rotor pole pairs is 2, and the number of pole shoes 112 is twice the number of rotor pole pairs.

[0115] It should be noted that the arrangement of the magnetic steel trough 111 described above is only an example, and this embodiment does not limit it.

[0116] The end of the magnet 130 can be flush with the end of the rotor body 110a; or, the end of the magnet 130 can protrude from the end of the rotor body 110a. When the end of the magnet 130 protrudes or is flush with the end of the rotor body 110a, the magnetic circuit can be more direct and clear, reducing unnecessary magnetic field diffusion and leakage.

[0117] In other embodiments, the end of the magnet 130 can be located within the magnet slot 111, and the distance between the end of the magnet 130 and the end of the rotor body portion 110a is A, with the thickness of the first rotor lamination 110 being h, where A ≤ 2h. That is, the end of the magnet 130 can also be recessed into the end of the rotor body portion 110a, and the recessed dimension can be controlled to be no greater than the thickness of two first rotor laminations 110, avoiding a significant decrease in magnetic field performance. Simultaneously, the stacking of the first rotor laminations 110 to form the rotor body portion 110a can protect the magnet 130.

[0118] Secondly, the present invention also provides a servo motor, which includes the rotor assembly 100 described above. Servo motors typically also include a stator assembly 200, a motor housing, and other components, which will not be described in detail in this embodiment.

[0119] like Figure 21 As shown in the figure, A is a schematic diagram of the magnetic field simulation of the prior art, and B is a schematic diagram of the magnetic field simulation of the rotor assembly 100 in the first embodiment of the present invention when applied to a servo motor; the comparison results of A and B in the figure are shown in the table below. By setting the rotor assembly 100 as shown in the figure... Figure 1 The rotor body 110a and the inertia section 120a are shown. The increase in leakage flux causes the rotor flux to decrease by only 0.22%, but the moment of inertia can be increased significantly, with an increase of up to 18%.

[0120]

[0121] Thanks to the improvements made to the rotor assembly 100 in the above embodiments, the servo motor of the second aspect embodiment of the present invention has the same technical effects as the rotor assembly 100 in the above embodiments. Further details will not be provided here.

[0122] The embodiments of the present invention have been described in detail above with reference to the accompanying drawings. However, the present invention is not limited to the above embodiments. Within the scope of knowledge possessed by those skilled in the art, various changes can be made without departing from the spirit of the present invention. Furthermore, unless otherwise specified, the embodiments of the present invention and the features thereof can be combined with each other.

Claims

1. A rotor assembly, characterized in that, include: The first rotor lamination has a plurality of circumferentially spaced magnetic slots, and the magnetic slots form pole shoes with the outer side wall of the first rotor lamination. The second rotor lamination has its axial projection on the first rotor lamination being the first projection, and the magnet slot and at least a portion of the pole shoe are located outside the first projection; A magnet, at least a portion of which is disposed within the magnet groove; In this configuration, a plurality of first rotor laminations are stacked to form a rotor body portion, and a plurality of second rotor laminations are stacked to form an inertia portion, wherein the inertia portion is located at at least one end of the rotor body portion.

2. The rotor assembly according to claim 1, characterized in that, The first rotor lamination includes a first yoke located radially inside the magnet slot; The second rotor lamination includes a second yoke portion, which overlaps with at least a portion of the first yoke portion.

3. The rotor assembly according to claim 2, characterized in that, The first rotor lamination includes a magnetic isolation bridge located between two adjacent magnet slots, and the magnetic isolation bridge is connected to the first yoke. The second rotor lamination includes teeth that connect to the outer wall of the second yoke, the teeth coinciding with at least a portion of the magnetic bridge.

4. The rotor assembly according to claim 2 or 3, characterized in that, The second rotor lamination is formed by breaking off the pole shoe and at least part of the magnetic bridge or breaking off the pole shoe from the first rotor lamination.

5. The rotor assembly according to claim 2 or 3, characterized in that, The maximum outer radius of the first rotor lamination is R1, and the maximum distance between the outer wall of the second rotor lamination and the shaft center is D. 2max Where R1 / 3 < D 2max <R1.

6. The rotor assembly according to claim 2 or 3, characterized in that, The number of pole shoes is twice the number of pole pairs of the rotor assembly, and the number of magnet slots is K times the number of pole shoes, where K is a positive integer.

7. The rotor assembly according to claim 6, characterized in that, The magnetic steel groove is elongated, and a magnetic bridge is formed between the ends of two adjacent magnetic steel grooves; or, An auxiliary groove is provided on the outer wall of the first rotor lamination, and the auxiliary groove is located between two adjacent magnet slots; a magnetic isolation bridge is formed between the end of the two adjacent magnet slots and the groove wall of the auxiliary groove.

8. The rotor assembly according to claim 7, characterized in that, The magnetic steel groove includes a first groove and a second groove that are at an angle to each other. The radial inner ends of the first groove and the second groove are close to each other and the radial outer ends are far apart from each other. In two adjacent magnetic steel grooves, the magnetic isolation bridge is formed between the radial outer ends of the first groove of one magnetic steel groove and the second groove of the other magnetic steel groove. The radial inner ends of the first groove and the second groove are connected, or the first groove and the second groove are separated by the magnetic isolation bridge.

9. The rotor assembly according to claim 7, characterized in that, The magnetic steel groove includes a third groove, a fourth groove, and a fifth groove. The third groove and the fourth groove extend radially and are spaced apart circumferentially. The fifth groove connects the radially inner end of the third groove and the radially inner end of the fourth groove. In two adjacent magnetic steel grooves, a magnetic isolation bridge is formed between one of the third grooves and the fourth groove of the other magnetic steel groove; or, The plurality of magnetic slots include a plurality of first magnetic slots and a plurality of second magnetic slots. The plurality of first magnetic slots are arranged radially along the first rotor lamination. A second magnetic slot is provided between the radial inner ends of two adjacent first magnetic slots. The two ends of the second magnetic slot and the two adjacent first magnetic slots respectively form the magnetic isolation bridge.

10. The rotor assembly according to claim 7, characterized in that, The magnetic slot is an arc-shaped slot that protrudes toward the axis of the first rotor lamination, and the magnetic bridge is formed between the inner sidewalls of two adjacent arc-shaped slots.

11. The rotor assembly according to claim 1, characterized in that, Along the axial direction, the end of the magnet protrudes beyond the end of the rotor body; or, The end of the magnet is flush with the end of the rotor body; or, The end of the magnet is located in the magnet slot, the distance between the end of the magnet and the end of the rotor body is A, the thickness of the first rotor lamination is h, and A≤2h.

12. The rotor assembly according to claim 1, characterized in that, The first rotor lamination has a first shaft hole, and the second rotor lamination has a second shaft hole, with the first shaft hole and the second shaft hole coinciding along the axial direction.

13. A servo motor, characterized in that, Includes the rotor assembly as described in any one of claims 1 to 12.

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