Rotor assembly for a permanent magnet synchronous direct drive motor

Abstract

The application provides a rotor assembly of a permanent magnet synchronous direct drive motor, and relates to the technical field of permanent magnet motors. The rotor assembly comprises a rotor core body, a placement slot is formed in the rotor core body in a circumferential direction, a permanent magnet is embedded in the placement slot, a copper alloy column penetrates the core in an axial direction to enhance the connection stiffness between silicon steel sheets, a heat dissipation ring is slidably arranged at both ends of the copper alloy column, an inclined head is connected to the heat dissipation ring through an elastic assembly, the elastic assembly drives the inclined head to abut against the permanent magnet to provide an axial and radial force to clamp the permanent magnet, a first heat driving assembly is used to drive the heat dissipation ring to move after absorbing heat to maintain the pre-tightening force of the elastic assembly, and a second heat driving assembly is used to drive the heat dissipation ring to move when the temperature exceeds a threshold value, so that the inclined head is attached to the end surface of the permanent magnet to establish a heat conduction path. In the application, the elastic assembly compensates for the gap in real time, the first heat driving assembly maintains the pre-tightening force to prevent attenuation, the copper alloy column expands to enhance the stiffness of the core when the temperature rises, the second heat driving assembly establishes surface contact heat conduction when overheating, and the heat dissipation ring rapidly dissipates heat to prevent demagnetization.

Description

Technical Field

[0001] This invention relates to the field of permanent magnet motor technology, and more particularly to the rotor assembly of a permanent magnet synchronous direct drive motor. Background Technology

[0002] The rotor assembly of a permanent magnet synchronous direct drive motor is typically formed by stacking silicon steel sheets to create an iron core. Slots are cut into the iron core, and permanent magnets are embedded within these slots and secured by adhesive or mechanical restraint. During motor operation, the rotor rotates at high speed, generating vibration and temperature rise. The silicon steel sheet stacks bear alternating loads, while the permanent magnets endure the coupling effect of centrifugal force and thermal stress.

[0003] The existing rotor assembly has two prominent problems: First, the thermal expansion coefficients of silicon steel sheets and permanent magnets are different, and gaps are generated between the placement slot and the permanent magnet when the temperature rises. Traditional fixing methods are prone to failure under high temperature vibration, resulting in the loosening of the permanent magnet. Second, the heat accumulated in the rotor core is difficult to be quickly discharged, and the permanent magnets are at risk of irreversible demagnetization due to overheating. Summary of the Invention

[0004] The purpose of this invention is to solve the problems in the prior art where the thermal expansion coefficients of silicon steel sheets and permanent magnets are different, resulting in gaps between the placement slot and the permanent magnet when the temperature rises, and the traditional fixing method is prone to failure under high temperature vibration, leading to loosening of the permanent magnet; the heat accumulation in the rotor core is difficult to dissipate quickly, and the permanent magnet overheating poses an irreversible demagnetization risk. The proposed invention is a rotor assembly for a permanent magnet synchronous direct drive motor.

[0005] To achieve the above objectives, the present invention adopts the following technical solution: The rotor assembly of a permanent magnet synchronous direct drive motor includes: a rotor core body formed by stacking multiple silicon steel sheets, with multiple placement slots evenly formed circumferentially inside; a permanent magnet embedded in the placement slots; multiple copper alloy pillars axially penetrating inside the rotor core body to enhance the connection stiffness between the silicon steel sheets; two heat dissipation rings slidably sleeved on the outer ends of the copper alloy pillars; a beveled head connected to the heat dissipation rings via an elastic component, the elastic component driving the beveled head to abut against the axial end face of the permanent magnet, providing axial and radial forces to clamp the permanent magnet; a first thermal drive component connected to the end of the copper alloy pillars, absorbing heat from the rotor core body and driving the heat dissipation rings to move towards the permanent magnet, maintaining the preload of the elastic component; and a second thermal drive component disposed inside the rotor core body, driving the heat dissipation rings to move when the temperature exceeds a threshold, so that the end face of the beveled head fits against the end face of the permanent magnet, establishing a heat conduction path.

[0006] Preferably, the elastic component includes a telescopic rod, a limiting plate, and a compression spring. The end of the telescopic rod is fixedly connected to the middle of the end face of the inclined head, the limiting plate is fixedly connected to the end of the telescopic rod away from the inclined head, and the telescopic rod is slidably connected to the inside of the heat dissipation ring.

[0007] Preferably, both ends of the permanent magnet are machined into bevels, and the bevel of the beveled head contacts the bevel of the end of the permanent magnet.

[0008] Preferably, the first thermal drive assembly includes a connecting plate, a guide sleeve, and a thermal expansion rod. The connecting plate is fixedly connected to the end of the copper alloy column, the guide sleeve is fixedly installed inside the connecting plate, the thermal expansion rod is disposed inside the guide sleeve, the inner end of the thermal expansion rod is fixedly connected to the inner bottom surface of the guide sleeve, and the outer end of the thermal expansion rod extends outward and abuts against the end face of the heat dissipation ring.

[0009] Preferably, the second thermal drive assembly includes a circular receiving groove and a memory spring. The circular receiving groove is formed inside the rotor core body, and the memory spring is disposed inside the circular receiving groove. The memory spring is connected between the bottom surface of the circular receiving groove and the end face of the heat dissipation ring.

[0010] Preferably, the interior of the heat dissipation ring is slidably connected to the outer surface of the copper alloy column, and the size of the heat dissipation ring matches the size of the rotor core body.

[0011] Preferably, the compression spring is initially in a stretched state, and the inclined head compresses the permanent magnet.

[0012] Preferably, the connecting plate, guide sleeve, heat dissipation ring, and beveled head all have thermal conductivity.

[0013] Preferably, the rotor core body has a mounting hole in the middle, and the mounting hole is used to install the rotating shaft.

[0014] Compared with the prior art, the beneficial effects of the present invention are: 1. The elastic component drives the inclined head to provide axial and radial forces to the permanent magnet, and immediately adaptively clamps it when a gap is generated; the first thermal drive component absorbs heat and maintains the pre-tightening force of the elastic component to prevent the clamping force from decaying due to high temperature creep; the copper alloy column penetrates the iron core and expands when the temperature rises, enhancing the interlayer connection stiffness of the silicon steel sheet. 2. The first thermal drive component maintains preload during normal temperature rise. When the temperature exceeds the threshold, the second thermal drive component is activated, driving the heat dissipation ring to form a surface contact with the inclined head for heat conduction. The large flat surface of the heat dissipation ring is used to quickly dissipate heat and prevent irreversible demagnetization of the permanent magnet. 3. The elastic component completes gap compensation instantaneously, unaffected by thermal conduction hysteresis; although the first thermal drive component responds more slowly, its function is to maintain the preload force for a long time. Attached Figure Description

[0015] Figure 1 This is a schematic diagram of the overall three-dimensional structure of the rotor assembly of the permanent magnet synchronous direct drive motor according to an embodiment of the present invention; Figure 2This is a schematic diagram of the internal structure of the rotor core body in the rotor assembly of the permanent magnet synchronous direct drive motor according to an embodiment of the present invention; Figure 3 This is a schematic diagram of the rotor assembly of the permanent magnet synchronous direct drive motor in the state where the thermal expansion rod is not extended, according to an embodiment of the present invention. Figure 4 This is a schematic diagram of the thermal expansion rod elongation state in the rotor assembly of the permanent magnet synchronous direct drive motor according to an embodiment of the present invention; Figure 5 This is a schematic diagram of the retracted state of the memory spring in the rotor assembly of the permanent magnet synchronous direct drive motor according to an embodiment of the present invention; Figure 6 This is a schematic diagram showing the placement of slots in the rotor assembly of a permanent magnet synchronous direct drive motor according to an embodiment of the present invention; Figure 7 This is a schematic diagram of the inclined head structure in the rotor assembly of the permanent magnet synchronous direct drive motor according to an embodiment of the present invention; Figure 8 This is a schematic diagram of the copper alloy column structure in the rotor assembly of a permanent magnet synchronous direct drive motor according to an embodiment of the present invention.

[0016] In the diagram: 100, rotor core body; 101, placement slot; 102, permanent magnet; 103, mounting hole; 200, copper alloy column; 300, connecting plate; 301, guide sleeve; 302, thermal expansion rod; 400, heat dissipation ring; 500, beveled head; 501, telescopic rod; 502, limiting plate; 503, compression spring; 600, circular receiving slot; 601, memory spring. Detailed Implementation

[0017] The technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments.

[0018] The terms used in this invention, such as "upper," "lower," "left," "right," "middle," and "one," are merely for clarity of description and are not intended to limit the scope of the invention. Any changes or adjustments to their relative relationships, without substantially altering the technical content, should also be considered within the scope of the invention.

[0019] like Figures 1-8As shown, the rotor assembly of the permanent magnet synchronous direct drive motor includes: a rotor core body 100, formed by stacking multiple silicon steel sheets, with multiple placement slots 101 evenly formed circumferentially inside; permanent magnets 102, embedded in the placement slots 101; multiple copper alloy pillars 200, axially penetrating inside the rotor core body 100 to enhance the connection rigidity between the silicon steel sheets; two heat dissipation rings 400, respectively slidably sleeved on the outer sides of the axial ends of the copper alloy pillars 200; and a beveled head 500, connected to the heat dissipation rings 400 via an elastic component. The component drives the inclined head 500 to abut against the axial end face of the permanent magnet 102, providing axial and radial force to clamp the permanent magnet 102; the first thermal drive component, connected to the end of the copper alloy column 200, absorbs the heat of the rotor core body 100 and drives the heat dissipation ring 400 to move towards the permanent magnet 102, maintaining the preload of the elastic component; the second thermal drive component, located inside the rotor core body 100, drives the heat dissipation ring 400 to move when the temperature exceeds the threshold, so that the end face of the inclined head 500 fits against the end face of the permanent magnet 102, establishing a heat conduction path.

[0020] In this embodiment, initially, the inclined heads 500 driven by the elastic components on both sides abut against the two ends of the permanent magnet 102, providing axial and radial force for support. When the motor is working, the rotor core body 100 rotates at high speed and generates vibration. The silicon steel sheet stack tends to loosen due to vibration. Multiple copper alloy pillars 200 penetrate the interior of the rotor core body 100 to enhance the connection stability between the silicon steel sheets. As the temperature rises due to mechanical friction, the thermal expansion coefficient of the silicon steel sheets is greater than that of the permanent magnet 102, creating a gap between the placement groove 101 and the permanent magnet 102. At this time, the inclined heads 500 driven by the elastic components adaptively abut against the two ends of the permanent magnet 102, providing support and fixation through axial and radial force to prevent loosening. At the same time, the copper alloy pillars 200 expand due to heat, further strengthening the connection strength between the silicon steel sheets. The device has good thermal conductivity. After absorbing heat, the first heat-driven component drives the heat dissipation ring 400 and the elastic component to move closer to the permanent magnet 102, ensuring that the elastic component always has the initial preload and that the pressure exerted by the inclined head 500 on the permanent magnet 102 is always sufficient. During this process, the elastic component reacts before the first heat-driven component and quickly and adaptively clamps the permanent magnet 102. The first heat-driven component then acts to maintain the preload of the elastic component. When the temperature continues to rise and exceeds the threshold, the second heat-driven component is activated and directly drives the heat dissipation ring 400 to move, so that the end face of the inclined head 500 forms a surface contact with the end face of the permanent magnet 102. In a short time, the heat of the permanent magnet 102 is transferred to the heat dissipation ring 400 through the inclined head 500, and the large flat surface of the heat dissipation ring 400 is used for rapid heat dissipation.

[0021] like Figure 2As shown, optionally, the elastic component includes a telescopic rod 501, a limiting plate 502, and a compression spring 503. The end of the telescopic rod 501 is fixedly connected to the middle of the end face of the inclined head 500, and the limiting plate 502 is fixedly connected to the end of the telescopic rod 501 away from the inclined head 500. The telescopic rod 501 is slidably connected to the interior of the heat dissipation ring 400.

[0022] In this embodiment, when a gap appears between the permanent magnet 102 and the placement groove 101 due to differences in thermal expansion, the preload of the compression spring 503 pushes the limiting plate 502. The limiting plate 502 causes the telescopic rod 501 to slide out along the inside of the heat dissipation ring 400. The telescopic rod 501 pushes the inclined head 500 against the end face of the permanent magnet 102, achieving instantaneous automatic compensation of the gap. The sliding engagement between the telescopic rod 501 and the heat dissipation ring 400 provides axial guidance for the inclined head 500.

[0023] like Figure 2 and Figure 7 As shown, optionally, both ends of the permanent magnet 102 are machined into bevels, and the bevel of the bevel head 500 is in contact with the bevel of the end of the permanent magnet 102.

[0024] In this embodiment, both ends of the permanent magnet 102 are machined into bevels, and the bevel of the bevel head 500 contacts the bevel of the end of the permanent magnet 102. When the elastic component drives the bevel head 500 to press against the end face of the permanent magnet 102, the bevel of the bevel head 500 cooperates with the bevel of the permanent magnet 102, decomposing the axial thrust of the elastic component into a clamping force along the axial direction of the permanent magnet 102 and a clamping force along the radial direction of the permanent magnet 102. The axial force restricts the axial movement of the permanent magnet 102, and the radial force presses the permanent magnet 102 against the bottom of the placement groove 101, thereby achieving bidirectional synchronous clamping of the permanent magnet 102.

[0025] like Figures 2-8 As shown, optionally, the first thermal drive assembly includes a connecting plate 300, a guide sleeve 301, and a thermal expansion rod 302. The connecting plate 300 is fixedly connected to the end of the copper alloy column 200. The guide sleeve 301 is fixedly installed inside the connecting plate 300. The thermal expansion rod 302 is disposed inside the guide sleeve 301. The inner end of the thermal expansion rod 302 is fixedly connected to the inner bottom surface of the guide sleeve 301. The outer end of the thermal expansion rod 302 extends outward and abuts against the end face of the heat dissipation ring 400.

[0026] In this embodiment, when the copper alloy column 200 conducts heat from inside the rotor core body 100 to the end, the thermal expansion rod 302 absorbs heat and extends linearly along the axial direction of the guide sleeve 301, pushing the heat dissipation ring 400 to slide closer to the permanent magnet 102. The heat dissipation ring 400 drives the overall displacement of the elastic component, compensating for the loss of preload caused by high-temperature creep or permanent deformation of the elastic component, so that the squeezing force of the inclined head 500 on the permanent magnet 102 is always maintained at the initial design level. The guide sleeve 301 constrains the expansion direction of the thermal expansion rod 302, ensuring the accuracy of the pushing path.

[0027] like Figure 2 As shown, optionally, the second thermal drive assembly includes a circular receiving groove 600 and a memory spring 601. The circular receiving groove 600 is opened inside the rotor core body 100, and the memory spring 601 is disposed in the circular receiving groove 600. The memory spring 601 is connected between the bottom surface of the circular receiving groove 600 and the end face of the heat dissipation ring 400.

[0028] In this embodiment, when the temperature of the rotor core body 100 rises to the phase transformation temperature threshold of the memory spring 601, the memory spring 601 undergoes a martensitic-to-austenitic phase transformation, resulting in contraction deformation. This causes the heat dissipation ring 400 to move axially along the copper alloy column 200 towards the permanent magnet 102, so that the end face of the inclined head 500 is in contact with the end face of the permanent magnet 102, establishing a heat conduction path from the permanent magnet 102 through the inclined head 500 to the heat dissipation ring 400. When the temperature drops below the phase transformation temperature, the memory spring 601 returns to its extended state, and the heat dissipation ring 400 resets under the rebound force of the elastic component.

[0029] like Figure 2 As shown, optionally, the interior of the heat dissipation ring 400 is slidably connected to the outer surface of the copper alloy column 200, and the size of the heat dissipation ring 400 matches the size of the rotor core body 100.

[0030] In this embodiment, the outer diameter of the heat dissipation ring 400 is similar to or equal to the outer diameter of the rotor core body 100, so that the heat dissipation ring 400 has a large heat dissipation surface. When the heat dissipation ring 400 is driven to move, it slides smoothly along the outer surface of the copper alloy column 200. The copper alloy column 200 provides axial sliding guidance for the heat dissipation ring 400. The large surface area of ​​the heat dissipation ring 400 forms effective convective heat exchange with the surrounding air when the rotor rotates, and quickly dissipates the heat from the permanent magnet 102 transferred through the heat conduction path.

[0031] like Figure 2 As shown, optionally, the compression spring 503 is initially in a stretched state, and the inclined head 500 compresses the permanent magnet 102.

[0032] In this embodiment, during assembly, the compression spring 503 is pre-stretched to store elastic potential energy. This pre-stretch force is transmitted to the inclined head 500 through the telescopic rod 501, so that the inclined head 500 applies a pre-tightening compressive force to the end face of the permanent magnet 102 in the initial state. When a gap is generated between the placement groove 101 and the permanent magnet 102 due to temperature changes, the compression spring 503 is released instantaneously based on the pre-stored elastic potential energy, pushing the inclined head 500 to follow and compensate for the gap, thus completing the clamping instantly when the gap is generated without waiting.

[0033] like Figures 1-8 As shown, optionally, the connecting plate 300, guide sleeve 301, heat dissipation ring 400 and bevel head 500 all have thermal conductivity.

[0034] In this embodiment, when the second thermal drive component moves the heat dissipation ring 400 so that the end face of the inclined head 500 is in contact with the end face of the permanent magnet 102, the heat of the permanent magnet 102 is conducted through the thermally conductive inclined head 500 to the heat dissipation ring 400, which also has thermal conductivity, and then dissipated from the heat dissipation ring 400 to the surrounding environment. The connecting plate 300 and the guide sleeve 301 have thermal conductivity, ensuring that the heat at the end of the copper alloy column 200 can be efficiently transferred to the thermal expansion rod 302, so that the thermal expansion rod 302 can sense the temperature change in time and generate the corresponding thermal expansion displacement, ensuring the response speed and driving accuracy of the first thermal drive component.

[0035] like Figure 1 As shown, optionally, a mounting hole 103 is provided in the middle of the rotor core body 100, and the mounting hole 103 is used to install the rotating shaft.

[0036] In this embodiment, the rotating shaft passes through the mounting hole 103 and is fixedly connected to the rotor core body 100. When the motor is working, the rotating shaft drives the entire rotor assembly to rotate. Multiple placement slots 101 are evenly distributed circumferentially around the mounting hole 103, and permanent magnets 102 are embedded in each placement slot 101. The magnetic field generated by each permanent magnet 102 is symmetrically distributed around the axis of the rotating shaft, ensuring the uniformity of the air gap magnetic field of the motor and the stability of the output torque.

[0037] The above description is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the scope of the technology disclosed in the present invention, based on the technical solution and inventive concept of the present invention, should be covered within the scope of protection of the present invention.

Claims

1. A rotor assembly of a permanent magnet synchronous direct drive motor, characterized in that, include: The rotor core body (100) is formed by stacking multiple silicon steel sheets, and multiple placement slots (101) are uniformly opened in the circumferential direction inside it; A permanent magnet (102) is embedded in the placement slot (101); Multiple copper alloy pillars (200) are axially inserted inside the rotor core body (100) to enhance the connection stiffness between silicon steel sheets; Two heat dissipation rings (400) are slidably sleeved on the outer sides of the axial ends of the copper alloy column (200); The beveled head (500) is connected to the heat dissipation ring (400) via an elastic component. The elastic component drives the beveled head (500) to abut against the axial end face of the permanent magnet (102) and provides axial and radial forces to clamp the permanent magnet (102). The first heat-driven component is connected to the end of the copper alloy column (200). After absorbing the heat of the rotor core body (100), it drives the heat dissipation ring (400) to move towards the permanent magnet (102) to maintain the preload of the elastic component. The second thermal drive component is located inside the rotor core body (100). When the temperature exceeds the threshold, it drives the heat dissipation ring (400) to move, so that the end face of the inclined head (500) is in contact with the end face of the permanent magnet (102) to establish a heat conduction path.

2. The rotor assembly of the permanent magnet synchronous direct drive motor according to claim 1, characterized in that, The elastic component includes a telescopic rod (501), a limiting plate (502), and a compression spring (503). The end of the telescopic rod (501) is fixedly connected to the middle of the end face of the inclined head (500). The limiting plate (502) is fixedly connected to the end of the telescopic rod (501) away from the inclined head (500). The telescopic rod (501) is slidably connected to the interior of the heat dissipation ring (400).

3. The rotor assembly of the permanent magnet synchronous direct drive motor according to claim 2, characterized in that, Both ends of the permanent magnet (102) are machined into bevels, and the bevel of the bevel head (500) is in contact with the bevel of the end of the permanent magnet (102).

4. The rotor assembly of the permanent magnet synchronous direct drive motor according to claim 1, characterized in that, The first thermal drive assembly includes a connecting plate (300), a guide sleeve (301), and a thermal expansion rod (302). The connecting plate (300) is fixedly connected to the end of the copper alloy column (200). The guide sleeve (301) is fixedly installed inside the connecting plate (300). The thermal expansion rod (302) is disposed inside the guide sleeve (301). The inner end of the thermal expansion rod (302) is fixedly connected to the inner bottom surface of the guide sleeve (301). The outer end of the thermal expansion rod (302) extends outward and abuts against the end face of the heat dissipation ring (400).

5. The rotor assembly of the permanent magnet synchronous direct drive motor according to claim 1, characterized in that, The second thermal drive assembly includes a circular receiving groove (600) and a memory spring (601). The circular receiving groove (600) is opened inside the rotor core body (100), and the memory spring (601) is disposed in the circular receiving groove (600). The memory spring (601) is connected between the bottom surface of the circular receiving groove (600) and the end face of the heat dissipation ring (400).

6. The rotor assembly of the permanent magnet synchronous direct drive motor according to claim 1, characterized in that, The interior of the heat dissipation ring (400) is slidably connected to the outer surface of the copper alloy column (200), and the size of the heat dissipation ring (400) matches the size of the rotor core body (100).

7. The rotor assembly of the permanent magnet synchronous direct drive motor according to claim 2, characterized in that, The compression spring (503) is initially in a stretched state, and the inclined head (500) presses against the permanent magnet (102).

8. The rotor assembly of the permanent magnet synchronous direct drive motor according to claim 4, characterized in that, The connecting plate (300), guide sleeve (301), heat dissipation ring (400), and bevel head (500) all have thermal conductivity.

9. The rotor assembly of the permanent magnet synchronous direct drive motor according to claim 1, characterized in that, The rotor core body (100) has a mounting hole (103) in the middle, and the mounting hole (103) is used to install the rotating shaft.

Images