Rotor structure and electric machine

Abstract

The application discloses a rotor structure and a motor, and belongs to the technical field of motors. The rotor structure comprises a rotor core, a plurality of permanent magnets which are arranged on the outer circumferential surface of the rotor core at intervals in the circumferential direction, at least one disassembly auxiliary structure which is arranged on the rotor core and is used for providing a starting point of the action of a disassembly tool so as to reduce the binding force between the permanent magnets and the rotor core, and at least one shielding structure which is arranged on the rotor core and is used for blocking the magnetic force action path between adjacent permanent magnets during disassembly. The application realizes the gradual low-stress peeling of the permanent magnets by pre-embedding the disassembly auxiliary structure and the shielding structure on the rotor core, eliminates the magnetic force mutation risk in the disassembly process from the root, realizes the lossless, safe and low-cost disassembly of the permanent magnets after magnetization, and guarantees the structural strength and electromagnetic performance of the motor under the normal operation state. The application further discloses a motor comprising the above rotor structure.

Description

Technical Field

[0001] This invention relates to the field of motor technology, and in particular to a rotor mechanism and a motor including the rotor structure, especially suitable for surface-mounted permanent magnet motors. Background Technology

[0002] Surface-mounted permanent magnet motors are widely used in servo drives, new energy vehicles, and industrial drives due to their advantages such as high efficiency, high power density, and high dynamic response. The rotor of this type of motor is typically fixed by bonding permanent magnets to the outer surface of the rotor core using structural adhesive, and then magnetizing it after bonding.

[0003] In the rework process of motor manufacturing and in the maintenance and repair of motors after they enter service, it is necessary to disassemble and separate the permanent magnets from the rotor core. However, because the permanent magnets and the rotor core are bonded over a large area of ​​the entire plane, the bonding strength is extremely high after the adhesive layer cures, making it difficult for conventional tools to effectively intervene. Forcibly disassembling them can easily lead to the magnets cracking or damage to the surface of the core.

[0004] Even more challenging is the fact that the magnetized permanent magnets exhibit extremely strong lateral attraction and radial adsorption forces. During disassembly, if a local bonding interface of a magnet fails, the magnetic force between adjacent magnets will be released instantaneously, causing the magnets to oscillate circumferentially or bounce radially, resulting in collisions and breakage. This not only causes irreversible damage to the magnets but also poses a serious safety hazard, easily injuring operators.

[0005] In existing technologies, some solutions attempt to enhance the magnet's anti-detachment performance by setting a wedge-shaped interference fit structure at the edge of the magnet. However, after assembly, this design tightly locks the magnet into the slot of the iron core, requiring extremely large radial or axial thrust during disassembly, or the use of destructive tools to forcibly pry it open. This inevitably leads to magnet breakage and damage to the iron core, making non-destructive disassembly completely impossible. Other solutions use complex hydraulic clamps, specialized disassembly tables, or precision heating equipment to disassemble the magnet. However, these solutions are costly, involve cumbersome procedures, are inefficient, and the heating process may have irreversible effects on the magnet's performance.

[0006] Furthermore, existing technical solutions do not consider the problem of sudden changes in magnetic force during the disassembly process from a structural perspective, and cannot effectively eliminate the risk of collision damage caused by sudden changes in magnetic force when the magnet is peeled off. Summary of the Invention

[0007] The purpose of this invention is to provide a rotor structure and a motor incorporating the rotor structure, so as to achieve non-destructive, safe and low-cost disassembly of permanent magnets, while ensuring the performance reliability of the motor under normal operating conditions, thereby solving the technical problem of difficult disassembly of magnets in the prior art.

[0008] To achieve the above objectives, the present invention provides the following technical solution: The present invention provides a rotor structure comprising: Rotor core; Multiple permanent magnets are arranged circumferentially on the outer circumferential surface of the rotor core. At least one disassembly aid structure is disposed on the rotor core to provide the starting point for the disassembly tool, thereby reducing the bonding force between the permanent magnet and the rotor core; And at least one shielding structure is disposed on the rotor core to block the magnetic force path between adjacent permanent magnets during disassembly.

[0009] The rotor structure of the present invention provides a safe and controllable starting point for disassembly tools by setting a disassembly auxiliary structure on the rotor core. This allows the disassembly tools to gradually intervene in the bonding interface from this starting point, achieving controllable separation between the permanent magnet and the rotor core. This avoids the breakage of the permanent magnet and scratches on the core caused by the forced intervention of tools in traditional disassembly methods.

[0010] Meanwhile, by setting a shielding structure on the rotor core, the magnetic force path between adjacent permanent magnets can be temporarily blocked during disassembly, eliminating the conditions for sudden changes in magnetic force. Therefore, during the permanent magnet stripping process, the lateral attraction between adjacent magnets is effectively shielded, preventing the target permanent magnet from circumferentially swaying or radially bouncing due to sudden changes in magnetic force. This ensures the smoothness and safety of the disassembly process and completely avoids the risk of magnet collision damage.

[0011] Based on the above technical solution, the present invention can be further improved as follows: Furthermore, the disassembly auxiliary structure is a groove structure formed on the outer circumferential surface of the rotor core, the groove structure corresponding to the end of the permanent magnet, and the depth of the groove structure gradually decreases in the direction away from the end of the permanent magnet.

[0012] The groove structure of this invention divides the bonding interface between the permanent magnet and the rotor core into a main bonding area and an end reserved area. The main bonding area maintains a complete bonding area to ensure bonding strength and reliability under normal motor operation. The end reserved area, due to the presence of the groove structure, forms a wedge-shaped space that allows disassembly tools to be inserted. The disassembly tools can safely intervene from this reserved area without damaging the main bonding area.

[0013] Furthermore, the circumferential dimension of the groove structure is adapted to the circumferential dimension of the permanent magnet, and the axial dimension of the groove structure is 10% to 20% of the axial dimension of the permanent magnet.

[0014] The circumferential dimensions of the groove structure match the width of the permanent magnet, ensuring that the disassembly tool can apply force evenly along the entire width of the permanent magnet, avoiding localized stress concentration. The aforementioned ratio range of the axial dimensions ensures that the end pre-reserved area provides sufficient operating space for the disassembly tool without excessively occupying the effective bonding area of ​​the permanent magnet, thus balancing disassembly convenience and operational reliability.

[0015] Furthermore, the bottom of the groove structure is provided with an arc transition portion, and the ratio of the radius of curvature of the arc transition portion to the depth of the groove structure is 1.5 to 2.5.

[0016] The circular arc transition effectively eliminates the geometric abrupt change at the bottom of the groove, avoiding stress concentration at sharp corners. According to the principles of fracture mechanics, when the radius of curvature approaches zero, the stress concentration factor approaches infinity; by controlling the ratio of the radius of curvature to the groove depth within the aforementioned range, the stress concentration factor can be reduced to an ideal level, ensuring that the magnet will not break at the sharp corners at the bottom of the groove during disassembly and force application.

[0017] Furthermore, there is an adhesive interface between the permanent magnet and the rotor core, and a stress adjustment groove is formed on the outer peripheral surface of the rotor core. The stress adjustment groove is located in the central region of the adhesive interface, and the depth of the stress adjustment groove changes in a gradient.

[0018] The stress-regulating groove creates localized variations in adhesive layer thickness within specific areas of the bonding interface, altering the adhesive strength distribution characteristics in those areas. During disassembly, the stress-regulating groove guides the peeling stress along a preset path and direction, enabling proactive control of the peeling process.

[0019] Furthermore, the depth of the stress-adjusting groove gradually decreases to zero from the middle region of the bonding interface towards both ends, forming a bonding strength distribution that is weak in the middle and strong at both ends.

[0020] According to fracture mechanics theory, the stress intensity factor K is positively correlated with crack depth, and cracks preferentially propagate from the region with the largest K value. In this scheme, the stress control groove has the greatest depth in the middle region, resulting in the largest stress intensity factor K value in this region. Therefore, the peeling crack preferentially starts from the middle region and then gradually propagates towards both ends. This achieves a gradual peeling from the middle to both ends, avoiding the stress release and magnet fracture caused by the instantaneous penetration of peeling cracks in traditional full-plane uniform bonding interfaces.

[0021] Furthermore, the cross-section of the stress regulating groove is arc-shaped so that the peeling stress is smoothly distributed along the arc surface.

[0022] The curved cross-section avoids stress concentration at sharp corners, allowing the peeling stress to be distributed evenly and smoothly along the curvature of the curved surface, further avoiding stress abrupt changes and the risk of magnet breakage.

[0023] Furthermore, a magnetic isolation bridge is provided between adjacent permanent magnets, and the shielding structure includes a slot formed on the magnetic isolation bridge, the slot extending axially along the rotor core for detachably accommodating the magnetic isolation component.

[0024] The magnetic bridge, by ensuring the mechanical strength of the rotor during high-speed operation, also suppresses magnetic leakage between adjacent magnets during normal motor operation. A slot is created at the center of the magnetic bridge; when magnets need to be disassembled, an independent non-magnetic shielding component can be inserted into the slot. Its non-magnetic properties cut off the lateral magnetic circuit between adjacent permanent magnets, achieving magnetic shielding. During normal motor operation, the shielding component is not inserted into the slot, and its normal operating performance is not affected.

[0025] Furthermore, the bottom of the slot is flush with the base surface of the rotor core, and the width of the slot is greater than the thickness of the magnetic shielding component, so that the magnetic shielding component and the slot are fitted with a clearance.

[0026] By matching the depth of the slot to the height of the magnetic shielding bridge, the mechanical strength of the iron core is not affected as it does not intrude into the yoke area. The clearance fit makes the insertion and removal of the magnetic shielding component extremely convenient, requiring only manual operation without any special tools, and does not generate additional stress on the slot or the iron core during insertion.

[0027] The present invention also provides an electric motor, including the rotor structure described above.

[0028] The motor of this invention features stress-regulating grooves on the rotor core that do not affect magnetic circuit performance, reducing the peeling force of the entire bonding surface, eliminating stress concentration, and achieving gradual peeling of the magnets, thus preventing damage caused by excessive force. Circumferentially spaced magnetic shielding slots allow for the insertion of magnetic shielding sheets during disassembly. This shields lateral magnetic forces and counteracts radial attraction forces, eliminating the window period of sudden magnetic force changes and ensuring the magnets remain stationary and stable throughout the peeling process, avoiding collision damage. Furthermore, the micro-groove structure between adjacent permanent magnets in the axial direction allows for operation using only conventional simple tools (such as a flathead screwdriver). No special tooling is required, significantly reducing maintenance costs and difficulty. Attached Figure Description

[0029] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0030] Figure 1This is a schematic diagram of the overall structure of the rotor structure of the present invention; Figure 2 This is a schematic diagram of the rotor core structure in the rotor structure of the present invention; Figure 3 yes Figure 2 Enlarged view of part A in the middle; Figure 4 This is a front sectional view of the rotor structure of the present invention; Figure 5 yes Figure 4 Enlarged view of part B in the middle; Figure 6 This is a cross-sectional view of the stress regulation groove in the rotor structure of the present invention.

[0031] In the picture: 1. Rotor core; 2. Magnetic shielding slot; 3. Wedge-shaped disassembly groove; 4. Magnetic bridge; 5. Stress regulating groove; 6. Permanent magnet steel. Detailed Implementation

[0032] To make the objectives, technical solutions, and advantages of this invention clearer, the technical solutions of this invention will be described in detail below. Obviously, the described embodiments are merely some embodiments of this invention, and not all embodiments. Based on the embodiments of this invention, all other implementation methods obtained by those skilled in the art without creative effort are within the scope of protection of this invention.

[0033] Example 1

[0034] like Figure 1 and Figure 2 As shown, the present invention provides a rotor structure, including a rotor core 1 and a plurality of permanent magnets 6 disposed on the outer circumferential surface of the rotor core 1. The plurality of permanent magnets 6 are arranged at intervals along the circumference, with multiple permanent magnets 6 in the same row, and are arranged sequentially along the axial direction of the rotor core 1. All permanent magnets 6 are bonded to the outer circumferential surface of the rotor core 1 using epoxy resin structural adhesive. The permanent magnets 6 are magnetized after bonding. The rotor core 1 is made of magnetically conductive material and has a cylindrical structure, with a shaft hole at its center for a rotating shaft to pass through.

[0035] like Figures 2-4As shown, a set of wedge-shaped disassembly grooves 3 are respectively formed on the outer circumferential surface of the rotor core 1, corresponding to the axial ends of each permanent magnet 6. The wedge-shaped disassembly groove 3 is a groove structure with a depth that gradually changes along the axial direction. Its circumferential width matches the circumferential width of the permanent magnet 6, so that the disassembly tool can apply force evenly along the entire width direction of the permanent magnet 6. The depth of the wedge-shaped disassembly groove 3 gradually decreases from the axial end face of the permanent magnet 6 towards the interior of the magnet bonding surface, and finally smoothly transitions with the outer circular surface of the rotor core 1.

[0036] It should be noted that the groove structure cannot be a V-shaped groove. The reason is that the bottom of a V-shaped groove is a sharp V-shaped corner (without a rounded transition). At the V-shaped corner of this type of cross-section, Kt > 3.0 (measured value), while the Kt of a trapezoidal groove with a rounded transition is approximately 1.4. The result of using a trapezoidal groove with a rounded transition is that the magnet breaks first at the V-shaped corner, with a breakage rate as high as 32.7%. When the disassembly tool is inserted into the V-shaped corner, the stress is concentrated sharply at the corner, and the magnet breaks instantly at the corner. The peeling process is sudden and discontinuous. As a result, the magnet is prone to local fracture and cannot achieve gradual peeling.

[0037] Test Analysis: Magnet dimensions: axial length 12mm, circumferential width 10mm, thickness 4mm; The magnet breakage rate varies depending on the parameters used in the wedge groove, as follows: The circumferential width of the wedge groove is 10mm (matching the circumferential width of the magnet); that is, the circumferential width = magnet width: magnet breakage rate 0.5%; Wedge groove circumferential width > magnet width: magnet breakage rate 15.2% (disassembly tool insertion unstable); Wedge groove circumferential width < magnet width: magnet breakage rate 32.7% (disassembly tools cannot be inserted); Wedge groove depth = 4mm × 0.17 = 0.68mm (take 0.6mm, upper limit). When the depth is less than 0.3mm: the disassembly starting point is insufficient, and the peeling cannot be effectively initiated; When the depth is greater than 0.6 mm: the core strength decreases, affecting motor performance; When the depth is 0.5mm (the magnet thickness is 4mm): the magnet breakage rate is the lowest, at 0.5%; Axial length of wedge groove = 12mm × 15% = 1.8mm (take 2mm); Axial length <10%: The disassembly starting point is too small, making it difficult to effectively initiate the stripping process; Axial length > 20%: Wastes core space and affects motor performance; Axial length = 15% (1.8mm when the axial length of the magnet is 12mm): the peeling force peak is the lowest, at 92.1N; The trapezoidal slope of the wedge groove = arctan(0.6 / 2) = 16.7°; The fillet radius is 0.6mm × 1.5 = 0.9mm.

[0038] Furthermore, the trapezoidal groove should be a trapezoidal groove with a rounded arc, and cannot be a simple trapezoidal groove. This has been verified through testing. Right-angled trapezoidal slot: Magnet breakage rate 5.2%; With arc-shaped trapezoidal groove: magnet breakage rate 0.5%.

[0039] It should also be noted that the wedge shape of the wedge-shaped disassembly groove in this invention refers to the gradual change in depth (gradually decreasing from the end of the magnet to the inside of the iron core), rather than the cross-sectional shape.

[0040] A smooth transition with the outer surface of the iron core means that the bottom of the slot has a circular arc transition, so its cross-sectional shape is a trapezoid with a circular arc transition.

[0041] Therefore, the bonding interface between the permanent magnet 6 and the rotor core 1 is divided into a main bonding area in the middle region and reserved areas at both ends. The main bonding area maintains a complete bonding area, providing sufficient bonding strength to ensure the reliability of the motor during high-speed operation. Due to the presence of the wedge-shaped disassembly groove 3, the reserved areas form a wedge-shaped gap with an opening facing the axial end face between the end of the permanent magnet 6 and the surface of the rotor core 1, providing a safe insertion space for the disassembly tool.

[0042] In one specific embodiment, the axial length of the wedge-shaped disassembly groove 3 is 2 mm. For a permanent magnet 6 with an axial length of 12 mm, this axial length is approximately 16.7% of the magnet's axial length, falling within the preferred range of 10%-20%. The depth of the wedge-shaped disassembly groove 3 is 0.5 mm. For a permanent magnet 6 with a thickness of 4 mm, this depth is approximately 12.5% ​​of the magnet's thickness, falling within the preferred range of 1 / 6-1 / 4.

[0043] like Figure 5 As shown, the wedge-shaped disassembly groove 3 has a specific inclined plane angle and bottom structure. The included angle between the wedge-shaped inclined plane and the outer circular surface of the rotor core 1 is controlled within the range of 10° to 20°, preferably 12° to 14°. This angle range ensures that the disassembly tool can effectively wedge in and generate sufficient peeling force, while avoiding damage to the magnets due to insufficient wedge force caused by an excessively small angle or excessive pushing force caused by an excessively large angle. The bottom of the wedge-shaped disassembly groove 3 is provided with an arc transition part, and the ratio of the radius of curvature R of the arc transition part to the groove depth h is 1.5 to 2.5. When R / h=2, the stress concentration factor Kt≈1.5, close to the ideal value; if R / h is too large (e.g., >5), it will reduce the effective depth of the groove and affect the disassembly effect; if R / h is too small (e.g., <1), stress concentration cannot be effectively avoided.

[0044] Taking a groove depth of h=0.5mm as an example, the radius of the arc R is taken to be 0.75mm to 1.25mm. This arc transition design effectively eliminates the geometric sharp corners at the bottom of the groove, avoids stress concentration during the disassembly process, and prevents the magnet from breaking at the sharp corners at the bottom of the groove.

[0045] It should be noted that in traditional planar bonding structures, the bonding interface between the magnet and the iron core is a uniform plane. When a peeling force is applied, the stress is uniformly distributed at the interface. According to fracture mechanics theory, when the stress intensity factor K at a certain point on the interface exceeds the critical value Kc, the interface will fracture. In a uniform interface, once a point fails, the stress will instantly concentrate in adjacent areas, leading to overall peeling.

[0046] In this embodiment, as Figure 2 and Figure 5 As shown, stress adjustment grooves 5 are also formed on the outer circumferential surface of the rotor core 1 in the bonding interface area of ​​each permanent magnet 6. The stress adjustment grooves 5 are located in the central area of ​​the bonding interface and extend along the axial direction of the rotor core 1. The depth of the stress adjustment grooves 5 varies in a gradient, with the depth being the largest in the middle area and gradually decreasing to zero towards both ends, forming a smooth arc-shaped gradient structure.

[0047] In one specific embodiment, the maximum depth of the middle region of the stress-adjusting groove 5 is 0.3 mm, which smoothly narrows to zero at both ends, with a width of 2 mm. This structure results in a bonding strength distribution between the permanent magnet 6 and the rotor core 1 that is strong at both ends and weak in the middle.

[0048] The depth distribution of the stress-regulating groove 5 along the axial direction can be expressed as h(x) = h0 - a·x 2 The relationship between the stress intensity factor K and the crack depth h is a quadratic function, where h0 is the maximum depth of the intermediate region, x is the axial distance from the intermediate region, and a is a constant. According to fracture mechanics theory, the relationship between the stress intensity factor K and the crack depth h is: , where σ is the applied peel stress. In this embodiment, h(x) is a quadratic function of x, therefore: This indicates that K(x) is maximum at x=0, and as |x| increases, K(x) gradually decreases, forming a gradient distribution.

[0049] Therefore, the stress intensity factor K reaches its maximum value in the middle region and gradually decreases as one moves away from the middle region, forming a gradient distribution that decreases from the middle to both ends. This gradient distribution causes the peeling crack to preferentially start from the middle region and then gradually extend to both ends, realizing a gradual peeling from the middle to both ends. This completely avoids the stress release and brittle fracture of the magnet caused by the instantaneous penetration of peeling cracks in traditional uniform bonding interfaces.

[0050] Mechanical description of the peeling process: The process of magnet stripping can be viewed as the propagation of interfacial cracks, and the following model can be established: Initial state: The magnet and the iron core are bonded together with epoxy resin, and the interface is uniform.

[0051] Apply external force: Apply a peeling force F from the end of the magnet.

[0052] Crack propagation: When F exceeds the critical value, micro-peeling first occurs at the interface in the middle region.

[0053] Gradual expansion: As F increases, the peeling area gradually expands from the middle to both ends, forming a wave-like peeling.

[0054] Peeling force-displacement relationship For the gradient degumming microgroove, the peeling force-displacement relationship is: ; Where Kc is the critical stress intensity factor and h(x) is the groove depth at position x.

[0055] As h(x) gradually decreases from the middle to both ends, F(x) also gradually decreases from the middle to both ends, forming a gentle peeling process.

[0056] like Figure 2 and Figure 6 As shown, a magnetic isolation bridge 4 is provided between two adjacent permanent magnets 6. The height of the magnetic isolation bridge is usually 1.2-1.5 times the axial length of the magnet. The magnetic isolation bridge 4 is a raised structure integrally formed by the rotor core 1. Its function is to ensure the mechanical strength of the rotor when rotating at high speed, and at the same time suppress the leakage magnetic field between adjacent permanent magnets 6 under normal operating conditions, thereby improving the operating efficiency of the motor.

[0057] At the center of each magnetic bridge 4, an axially penetrating magnetic shielding slot 2 is provided along the axial direction of the rotor core 1. The depth of the magnetic shielding slot 2 matches the height of the magnetic bridge 4, and the bottom of the slot is flush with the outer circular surface of the rotor core 1, without intruding into the bonding area of ​​the permanent magnet 6, and without damaging the structural strength of the core yoke.

[0058] In one specific embodiment, the width of the magnetic shielding slot 2 is 1.5mm.

[0059] The invention also includes a magnetic shielding sheet, which is a non-magnetic thin-film component independent of the rotor structure and is used only in the disassembly process of the permanent magnet 6. The thickness of the magnetic shielding sheet is 1.3mm to 1.4mm, forming a gap fit of 0.1mm to 0.2mm between it and the width of the magnetic shielding slot 2, allowing the operator to insert the magnetic shielding sheet axially into the magnetic shielding slot 2 by hand without any special tools.

[0060] When the magnetic shielding sheet is inserted into the slot, its non-magnetic properties cut off the lateral magnetic circuit between adjacent permanent magnets 6, effectively shielding the lateral attraction force and eliminating the risk of sudden magnetic force changes during disassembly. Under normal motor operation, the magnetic shielding sheet is not inserted into the slot to avoid affecting the motor's normal operating performance.

[0061] Table 1 shows the quantitative effect of magnetic shielding sheet on shielding magnetic force. Test method: Use a magnetometer to measure the lateral attractive force of adjacent magnets on the target magnet; Test environment: 25°C, 50% humidity, magnetization strength of the magnet 1.4T; Tests showed that the reduction ratio and magnet stability differed depending on the insertion depth with and without a magnetic shield. See Table 1 for details.

[0062] Operating instructions: First, place the rotor to be disassembled horizontally on a fixed fixture to restrict the rotor's circumferential rotation and axial movement, ensuring that the rotor remains stable during disassembly and avoiding uneven force on the magnets caused by rotor shaking.

[0063] Then, remove the non-magnetic shielding sheet and insert it axially into the magnetic shielding slots 2 on both sides of the permanent magnet 6 to be disassembled. After the shielding sheet is inserted, the lateral magnetic circuit between adjacent permanent magnets 6 is effectively blocked, the lateral attraction force is shielded, and the target magnet is in a magnetically isolated state, eliminating the potential for sudden magnetic changes during subsequent disassembly.

[0064] Next, take two ultra-thin wedge-shaped wedge cutters (a regular flathead screwdriver will suffice) and align them with the wedge-shaped disassembly grooves 3 at both ends of the permanent magnet 6. Insert the cutting edge of the wedge cutter into the wedge-shaped gap through the pre-set safety gap at the axial end face of the permanent magnet 6, ensuring that the wedge cutter does not scratch the surface of the iron core or damage the edge of the magnet.

[0065] Two top cutters are slowly advanced symmetrically and uniformly along the axial direction of the permanent magnet 6. During the advancement of the top cutters, the inclined surface of the wedge-shaped disassembly groove 3 gradually converts the axial thrust of the top cutters into a normal peeling force, causing the end pre-reserved area of ​​the permanent magnet 6 to separate from the iron core surface first. As the top cutters advance further, the peeling force is transmitted to the middle area. The presence of the stress regulating groove 5 results in the lowest bonding strength in the middle area of ​​the bonding interface. Therefore, peeling cracks preferentially start from the middle area and gradually extend to both ends. Throughout the peeling process, the peeling force remains stable, without any obvious stress surges or drops.

[0066] Finally, once the permanent magnet 6 is completely detached from the rotor core 1, the magnet will not oscillate circumferentially or bounce radially due to the shielding effect of the magnetic shielding sheet. The operator can then smoothly pull it out axially. The entire disassembly process does not require complex hydraulic clamps, large specialized disassembly tables, or precision heating equipment; it can be completed with only conventional and simple tools, making the operation simple, safe, and reliable.

[0067] The wedge-shaped disassembly groove provides the starting point for force application and the conditions for gradual peeling, while the stress-regulating groove enables the gradient distribution of peeling stress and active control of the gradual peeling path. The magnetic shielding slot eliminates the risk of sudden magnetic force changes during disassembly. The synergistic effect of these three components allows for safe, fast, and low-cost non-destructive disassembly of the magnetized permanent magnet with an extremely low breakage rate, completely solving the two major industry-wide problems in the disassembly of surface-mounted permanent magnet motor magnets.

[0068] Example 2

[0069] This invention also provides an electric motor, specifically a surface-mounted permanent magnet motor, including a rotor structure. Specifically, as shown... Figure 1 and Figure 2 As shown, the rotor structure includes a rotor core 1 and multiple permanent magnets 6 disposed on the outer circumferential surface of the rotor core 1. The multiple permanent magnets 6 are arranged at circumferential intervals, with multiple permanent magnets 6 in the same row, and are arranged sequentially along the axial direction of the rotor core 1. All permanent magnets 6 are bonded to the outer circumferential surface of the rotor core 1 using epoxy resin structural adhesive. The permanent magnets 6 are magnetized after bonding. The rotor core 1 is made of magnetically conductive material and has a cylindrical structure, with a shaft hole at its center for the shaft to pass through.

[0070] like Figures 2-4 As shown, a set of wedge-shaped disassembly grooves 3 are respectively formed on the outer circumferential surface of the rotor core 1, corresponding to the axial ends of each permanent magnet 6. The wedge-shaped disassembly groove 3 is a groove structure with a depth that gradually changes along the axial direction. Its circumferential width matches the circumferential width of the permanent magnet 6, so that the disassembly tool can apply force evenly along the entire width direction of the permanent magnet 6. The depth of the wedge-shaped disassembly groove 3 gradually decreases from the axial end face of the permanent magnet 6 towards the interior of the magnet bonding surface, and finally smoothly transitions with the outer circular surface of the rotor core 1.

[0071] Therefore, the bonding interface between the permanent magnet 6 and the rotor core 1 is divided into a main bonding area in the middle region and reserved areas at both ends. The main bonding area maintains a complete bonding area, providing sufficient bonding strength to ensure the reliability of the motor during high-speed operation. Due to the presence of the wedge-shaped disassembly groove 3, the reserved areas form a wedge-shaped gap with an opening facing the axial end face between the end of the permanent magnet 6 and the surface of the rotor core 1, providing a safe insertion space for the disassembly tool.

[0072] In one specific embodiment, the axial length of the wedge-shaped disassembly groove 3 is 2 mm. For a permanent magnet 6 with an axial length of 12 mm, this axial length is approximately 16.7% of the magnet's axial length, falling within the preferred range of 10%-20%. The depth of the wedge-shaped disassembly groove 3 is 0.5 mm. For a permanent magnet 6 with a thickness of 4 mm, this depth is approximately 12.5% ​​of the magnet's thickness, falling within the preferred range of 1 / 6-1 / 4.

[0073] like Figure 5 As shown, the wedge-shaped disassembly groove 3 has a specific bevel angle and bottom structure. The angle between the wedge-shaped bevel and the outer circular surface of the rotor core 1 is controlled within the range of 10° to 20°, preferably 12° to 14°. This angle range ensures that the disassembly tool can effectively wedge in and generate sufficient peeling force, while avoiding damage to the magnet due to insufficient wedging force caused by an excessively small angle or excessive pushing force caused by an excessively large angle. The bottom of the wedge-shaped disassembly groove 3 is provided with an arc transition section, the ratio of the radius of curvature R of the arc transition section to the groove depth h is 1.5 to 2.5. Taking a groove depth h = 0.5 mm as an example, the arc radius R is 0.75 mm to 1.25 mm. This arc transition design effectively eliminates the geometric sharp corners of the groove bottom, avoids stress concentration during the disassembly force application process, and prevents the magnet from breaking at the sharp corners of the groove bottom.

[0074] like Figure 2 and Figure 5 As shown, stress adjustment grooves 5 are also formed on the outer circumferential surface of the rotor core 1 in the bonding interface area of ​​each permanent magnet 6. The stress adjustment grooves 5 are located in the central area of ​​the bonding interface and extend along the axial direction of the rotor core 1. The depth of the stress adjustment grooves 5 varies in a gradient, with the depth being the largest in the middle area and gradually decreasing to zero towards both ends, forming a smooth arc-shaped gradient structure.

[0075] In one specific embodiment, the maximum depth of the middle region of the stress-adjusting groove 5 is 0.3 mm, which smoothly narrows to zero at both ends, with a width of 2 mm. This structure results in a bonding strength distribution between the permanent magnet 6 and the rotor core 1 that is strong at both ends and weak in the middle.

[0076] The depth distribution of the stress-regulating groove 5 along the axial direction can be expressed as h(x) = h0 - a·x 2 The relationship between the stress intensity factor K and the crack depth h is a quadratic function, where h0 is the maximum depth of the intermediate region, x is the axial distance from the intermediate region, and a is a constant. According to fracture mechanics theory, the relationship between the stress intensity factor K and the crack depth h is: Where σ is the applied peel stress. Consequently, the stress intensity factor K reaches its maximum value in the middle region and gradually decreases with distance from the middle, forming a gradient distribution that decreases from the middle to both ends. This gradient distribution causes peel cracks to preferentially initiate in the middle region and then gradually propagate towards both ends, achieving a gradual peel from the middle to both ends. This completely avoids the stress release and brittle fracture of the magnet caused by the instantaneous penetration of peel cracks in traditional uniform adhesive interfaces.

[0077] like Figure 2 and Figure 6 As shown, a magnetic isolation bridge 4 is provided between two adjacent permanent magnet steels 6. The magnetic isolation bridge 4 is a raised structure integrally formed by the rotor core 1. Its function is to ensure the mechanical strength of the rotor when rotating at high speed, and at the same time suppress the leakage magnetic field between adjacent permanent magnet steels 6 under normal operating conditions, thereby improving the operating efficiency of the motor.

[0078] At the center of each magnetic bridge 4, an axially penetrating magnetic shielding slot 2 is provided along the axial direction of the rotor core 1. The depth of the magnetic shielding slot 2 matches the height of the magnetic bridge 4, and the bottom of the slot is flush with the outer circular surface of the rotor core 1, without intruding into the bonding area of ​​the permanent magnet 6, and without damaging the structural strength of the core yoke.

[0079] In one specific embodiment, the width of the magnetic shielding slot 2 is 1.5mm.

[0080] The invention also includes a magnetic shielding sheet, which is a non-magnetic thin-film component independent of the rotor structure and is used only in the disassembly process of the permanent magnet 6. The thickness of the magnetic shielding sheet is 1.3mm to 1.4mm, forming a gap fit of 0.1mm to 0.2mm between it and the width of the magnetic shielding slot 2, allowing the operator to insert the magnetic shielding sheet axially into the magnetic shielding slot 2 by hand without any special tools.

[0081] When the magnetic shielding sheet is inserted into the slot, its non-magnetic properties cut off the lateral magnetic circuit between adjacent permanent magnets 6, effectively shielding the lateral attraction force and eliminating the risk of sudden magnetic force changes during disassembly. Under normal motor operation, the magnetic shielding sheet is not inserted into the slot to avoid affecting the motor's normal operating performance.

[0082] Table 2 shows examples of parameter adjustments for different motor models.

[0083] The table shows the parameter range of the wedge groove for different types of motors with different magnet sizes.

[0084] Circumferential width: must always match the circumferential width of the magnet. Depth: Maintain a proportional relationship with the magnet thickness (depth = magnet thickness × 0.17-0.25) Axial length: Maintain a proportional relationship with the axial length of the magnet (axial length = magnet axial length × 0.1-0.2) Trapezoid slope: Maintain within the range of 10°-20°, preferably 12°-14° Fillet radius: Maintain a proportional relationship with depth (R = 1.2 - 2.0 × depth) Arc radius selection Design values: Arc radius R≈0.6mm (groove depth h=0.3mm, R / h≈2) It should be noted that the various dimensional adjustments of this invention must meet the following requirements: The depth and axial length of the wedge groove are adjusted proportionally to the size of the magnet; the angle of the wedge slope remains constant at 12°-14°, and the radius of the bottom fillet is adjusted according to the groove depth by R / h=1.5-2.5.

[0085] For newly developed motors, it is recommended to design the axial length of the wedge groove within the range of 10%-20% of the axial length of the magnet. The depth of the wedge groove is recommended to be 1 / 6-1 / 4 of the thickness of the magnet, and the radius of the fillet at the bottom of the groove is recommended to be twice the depth of the groove (R=2h).

[0086] First, it should be noted that "inward" refers to the direction towards the center of the storage space, while "outward" refers to the direction away from the center of the storage space.

[0087] In the description of this invention, it should be understood that the terms "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," "counterclockwise," "axial," "radial," and "circumferential" indicate the orientation or positional relationship based on the appendix. Figure 1 The orientations or positional relationships shown are for the purpose of facilitating and simplifying the description of the present invention, and are not intended to indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as limiting the present invention.

[0088] 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 technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this invention, "a plurality of" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0089] In this invention, unless otherwise explicitly specified and limited, the terms "installation," "connection," "linking," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components, unless otherwise explicitly limited. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0090] In this invention, unless otherwise explicitly specified and limited, "above" or "below" the second feature can mean that the first feature is in direct contact with the second feature, or that the first feature is in indirect contact with the second feature through an intermediate medium. Furthermore, "above," "over," and "on top" of the second feature can mean that the first feature is directly above or diagonally above the second feature, or simply that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature can mean that the first feature is directly below or diagonally below the second feature, or simply that the first feature is at a lower horizontal level than the second feature.

[0091] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "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 present 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. Moreover, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of different embodiments or examples.

[0092] The above description is merely a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in the present invention should be included within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope of the claims.

Claims

1. A rotor structure, characterized in that, include: Rotor core; Multiple permanent magnets are arranged circumferentially on the outer circumferential surface of the rotor core. At least one disassembly aid structure is disposed on the rotor core to provide the starting point for the disassembly tool, thereby reducing the bonding force between the permanent magnet and the rotor core; as well as At least one shielding structure is disposed on the rotor core to block the magnetic force path between adjacent permanent magnets during disassembly.

2. The rotor structure according to claim 1, characterized in that, The disassembly aid structure includes a groove structure formed on the outer circumferential surface of the rotor core, the groove structure corresponding to the end of the permanent magnet, and the depth of the groove structure gradually decreases in the direction away from the end of the permanent magnet.

3. The rotor structure according to claim 2, characterized in that, The circumferential dimension of the groove structure is adapted to the circumferential dimension of the permanent magnet, and the axial dimension of the groove structure is 10% to 20% of the axial dimension of the permanent magnet.

4. The rotor structure according to claim 2, characterized in that, The bottom of the groove structure is provided with an arc transition section, and the ratio of the radius of curvature of the arc transition section to the depth of the groove structure is 1.5 to 2.

5.

5. The rotor structure according to claim 1, characterized in that, There is an adhesive interface between the permanent magnet and the rotor core. The outer circumferential surface of the rotor core is provided with a stress adjustment groove. The stress adjustment groove is located in the central area of ​​the adhesive interface, and the depth of the stress adjustment groove changes in a gradient.

6. The rotor structure according to claim 5, characterized in that, The depth of the stress-adjusting groove gradually decreases to zero from the middle region of the bonding interface towards both ends, forming a bonding strength distribution that is weak in the middle and strong at both ends.

7. The rotor structure according to claim 6, characterized in that, The stress regulating groove has an arc-shaped cross-section to ensure that the peeling stress is smoothly distributed along the arc surface.

8. The rotor structure according to claim 1, characterized in that, A magnetic isolation bridge is provided between adjacent permanent magnets. The shielding structure is a slot opened on the magnetic isolation bridge. The slot extends along the axial direction of the rotor core and is used to detachably accommodate the magnetic isolation component.

9. The rotor structure according to claim 8, characterized in that, The bottom of the slot is flush with the base surface of the rotor core, and the width of the slot is greater than the thickness of the magnetic shielding component, so that the magnetic shielding component and the slot are fitted with a clearance.

10. An electric motor, characterized in that, The rotor structure includes any one of claims 1-9.

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