Rotor structure for improving critical rotating speed of rotor

Abstract

The invention relates to the technical field of permanent magnet motors, in particular to a rotor structure for improving the critical rotating speed of a rotor, which comprises a rotating shaft, a rotor core and a rotor pressing plate, a de-weighting hole is formed in the rotating shaft; the rotor pressing plate comprises a first pressing plate and a second pressing plate which are respectively arranged at two ends of the rotor iron core; wherein the de-weight hole and the rotating shaft extend in the same direction and are coaxially arranged; the length of the de-weight hole is greater than half of the length of the rotating shaft; the de-weighting hole is provided with an opening on the end face of the rotating shaft close to the second pressing plate; the first pressing plate comprises a pressing plate body and a thickening layer which are connected. The thickening layer is located on the side, away from the second pressing plate, of the pressing plate body. The thickening layer is formed in the area, close to the outer ring, of the pressing plate body; and the pressing plate main body, the thickening layer and the second pressing plate are consistent in thickness. The critical rotating speed value of the rotor with the thick rotating shaft can be effectively improved, and the situation that the rotating shaft needs to be further thickened due to the fact that the preset critical rotating speed threshold value of the rotor is not reached can be avoided.

Description

Technical Field

[0001] This invention relates to the field of permanent magnet motor technology, and more specifically to a rotor structure for increasing the critical speed of the rotor. Background Technology

[0002] As industrial equipment demands higher power performance, the required motor speed continues to increase. Under high-speed operation, motor vibration and noise become increasingly prominent. The rotor critical speed, a core indicator determining motor operational stability, is crucial for effectively suppressing resonance and extending motor lifespan, thus becoming a key design requirement for high-speed motors.

[0003] The mainstream traditional method for increasing the critical speed of a rotor is to increase the diameter of the motor shaft. This approach increases the critical speed by increasing the stiffness of the shaft system, but it does not consider weight control requirements during the design process. In applications such as new energy vehicles and drones, where there are clear requirements for lightweight motors, increasing the shaft diameter leads to an increase in the overall weight and installation space, making it unsuitable for actual use and limiting its application scope.

[0004] Further analysis reveals that simply increasing the shaft diameter has significant limitations in its optimization effect: the increased weight due to the increased shaft diameter will have a reverse inhibitory effect on the critical speed, resulting in a limited increase in the critical speed threshold. In this case, to achieve the design target critical speed, the shaft diameter needs to be further increased, leading to increased motor manufacturing costs and weight.

[0005] The current market has an increasingly urgent demand for lightweight and compact motor products, which traditional shaft diameter thickening solutions cannot meet, leading to a decline in product market competitiveness. Therefore, there is an urgent need to develop a rotor structure optimization solution that balances critical speed improvement, lightweight design, and cost control, addressing the core pain points of existing technologies. Summary of the Invention

[0006] The purpose of this invention is to provide a rotor structure that increases the critical speed of the rotor.

[0007] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0008] A rotor structure for increasing the critical speed of a rotor includes a rotating shaft and a rotor core and a rotor pressure plate that are fixedly sleeved and assembled on the rotating shaft.

[0009] The rotating shaft is provided with a weight-removing hole;

[0010] The rotor pressure plate includes a first pressure plate and a second pressure plate respectively disposed at both ends of the rotor core;

[0011] The weight-removing hole extends in the same direction as the rotating shaft and is coaxially arranged; the length of the weight-removing hole is greater than half the length of the rotating shaft; the weight-removing hole has an opening on the end face of the rotating shaft near the second pressure plate;

[0012] The first pressure plate includes a pressure plate body and a thickening layer connected to each other. The thickening layer is located on the side of the pressure plate body away from the second pressure plate. The thickening layer is formed on the pressure plate body in a region near the outer ring. The pressure plate body, the thickening layer and the second pressure plate have the same thickness.

[0013] The rotor structure is configured such that the opening of the weight-removing hole faces the second pressure plate, and the length of the weight-removing hole is greater than half the length of the rotating shaft. Combined with the thickening layer provided on the first pressure plate, the thickness of the pressure plate body, the thickening layer and the second pressure plate are consistent, so that the rotor structure has a set rotor critical speed value. Under the set rotor critical speed value, the rotor dynamic balance state of the rotor structure in the direction close to the first pressure plate tends to be stable.

[0014] The assembly of the shaft, rotor core, and rotor pressure plate is a standard setup and will not be described in detail here. The rotor pressure plate serves to position the rotor core, which is its current purpose and will not be elaborated upon here.

[0015] The rotating shaft has a de-weighting hole that extends in the same direction as the shaft and is longer than half the length of the shaft, which can be considered as an excessive length. The de-weighting hole is coaxial with the rotating shaft, which allows for a larger cross-sectional size and a regular structure.

[0016] It should be noted that increasing the shaft diameter increases stiffness, and the higher the stiffness, the higher the critical speed. However, increasing the shaft diameter also increases its weight, resulting in a lower critical speed. To effectively increase the critical speed, the increase in shaft diameter should be accompanied by a smaller increase in weight. Therefore, at the same weight, a hollow shaft with a larger outer diameter (i.e., the shaft itself) will have better stiffness and a higher critical speed than a solid shaft with a smaller outer diameter. Based on this, a longer de-weighting hole can significantly reduce the weight of the shaft, ensuring an effective increase in the critical speed of a rotor with a thicker shaft. It also avoids the need to further thicken the shaft if the predetermined rotor critical speed threshold is not reached. The de-weighting hole is coaxial with the shaft, and its cross-sectional size can be larger, further ensuring a significant reduction in shaft weight.

[0017] It should also be noted that the deeper the de-balancing hole, the greater the degree of misalignment between the hole and the shaft due to factors such as actual machining precision. This makes it easier for the rotor's dynamic balance accuracy to deviate from the design requirements, resulting in significant eccentricity and an imbalance exceeding the allowable range. When the rotor rotates, the imbalance caused by eccentricity generates an inertial centrifugal force proportional to the square of the rotational speed. When the excitation frequency of this centrifugal force approaches the natural frequency of the rotor system, resonance is easily induced. When resonance occurs, the rotor's dynamic deflection increases significantly, reducing the system's equivalent stiffness. Consequently, the rotor is more likely to reach the critical speed within the operating speed range, exacerbating the vibration risk.

[0018] If the length of the de-balance hole is greater than half the length of the shaft, it can easily lead to deviations between the rotor's dynamic balance accuracy and design requirements. Therefore, de-balance is necessary. For the first pressure plate without a thickened area, due to its limited thickness, the weight reduction through drilling is limited, resulting in poor de-balance and failing to achieve the required dynamic balance accuracy. By adding an additional thickened layer with a thickness consistent with the main body of the first pressure plate, the weight reduction through drilling is increased, making it easier to bring the rotor's dynamic balance accuracy closer to the design requirements. This helps to address the issue of the rotor's critical speed decreasing due to dynamic balance deviations.

[0019] The length of the weight-removing hole is greater than half the length of the shaft, and the hole is formed on the end face of the shaft near the second pressure plate. That is, the weight-removing hole is formed by opening from the end of the shaft near the second pressure plate. The deeper the weight-removing hole goes, the greater the eccentricity between the area of ​​the weight-removing hole and the shaft, and the greater the imbalance. Therefore, a thickened layer is provided on the first pressure plate, while no thickened layer is needed on the second pressure plate to control the rotor weight and cost. Controlling the rotor weight is beneficial for achieving rotor lightweighting and improving product competitiveness.

[0020] In some implementations, a thickened area may be provided on the second pressure plate.

[0021] The thickened layer is formed on the pressure plate body in the area near the outer ring, but not simultaneously in the area near the inner ring. This can achieve the purpose of weight reduction to adjust the dynamic balance accuracy of the rotor, and also avoid adding ineffective structures, thus controlling the rotor weight and cost.

[0022] In a further technical solution, the rotor core includes a first magnetic steel core and a second magnetic steel core, both sleeved and assembled on the rotating shaft; the first magnetic steel core is attached to the pressure plate body, and the second magnetic steel core is attached to the second pressure plate; a separator sleeved and assembled on the rotating shaft is provided between the first magnetic steel core and the second magnetic steel core.

[0023] The rotor core has magnets, and the first magnetized iron core and the second magnetized iron core are separated by a separator. The first magnetized iron core and the second magnetized iron core can be regarded as the main drive and the auxiliary drive, respectively. Under normal working conditions, only the main drive runs, and the main and auxiliary drives work together when high torque is required.

[0024] Preferably, the first magnetized steel core and the second magnetized steel core are symmetrically arranged in the axial direction of the rotating shaft.

[0025] The assembly method of the iron core structure and the rotating shaft is existing and will not be described in detail here.

[0026] In a further technical solution, the separator includes:

[0027] The third pressure plate is sleeved and assembled on the rotating shaft and attached to the first magnetic steel core;

[0028] An intermediate pressure sleeve is fitted onto the rotating shaft and adheres to the third pressure plate;

[0029] The fourth pressure plate is fitted onto the rotating shaft and adheres to the second magnetic steel core and the intermediate pressure sleeve;

[0030] The third pressure plate, the intermediate pressure sleeve, and the fourth pressure plate are all fixed relative to the rotating shaft.

[0031] Both the third and fourth pressure plates are non-magnetic.

[0032] The intermediate pressure sleeve controls the distance between the first and second magnetized steel cores. Located in the central region of the shaft along its axial direction, the intermediate pressure sleeve enhances the bending stiffness of the central region, thereby reducing the bending deflection of the shaft under load. The smaller the deflection, the stronger the shaft's resistance to bending deformation. Under the premise of unchanged support structure and mass distribution, the critical speed of the shaft will also increase accordingly, making resonance less likely. The intermediate pressure sleeve can be made of steel.

[0033] The third and fourth pressure plates can be made of aluminum. They are non-magnetic, which blocks the magnetic circuit connection between the first and second magnetic steel cores, thus preventing the motor torque output from decreasing and making them lighter in weight.

[0034] In a further technical solution, the third pressure plate and the fourth pressure plate are respectively fixedly sleeved on both ends of the intermediate pressure sleeve in the axial direction of the rotating shaft, and the two ends of the intermediate pressure sleeve in the axial direction of the rotating shaft are respectively attached to the first magnetic steel core and the second magnetic steel core, and the intermediate pressure sleeve is interference-fitted with the rotating shaft.

[0035] The third and fourth pressure plates can be heat-fitted onto the intermediate pressure sleeve to secure them. Afterward, only an interference fit between the intermediate pressure sleeve and the shaft is required, facilitating installation of all three components and improving rotor assembly efficiency. At this point, the third and fourth pressure plates and the intermediate pressure sleeve can be considered a single integrated structure. This design effectively ensures the achievement of the aforementioned effect of enhancing the bending stiffness of the shaft's central region.

[0036] Taking the intermediate pressure sleeve as an example, the intermediate pressure sleeve can position the first magnetic steel core and the second magnetic steel core in the axial direction of the rotating shaft.

[0037] Preferably, the third pressure plate and the fourth pressure plate are symmetrically arranged in the axial direction of the rotating shaft. They can be symmetrically arranged based on a symmetrical plane that passes through the center point of the rotating shaft and is perpendicular to the axis of the rotating shaft.

[0038] The intermediate pressure sleeve is attached to the first and second magnetic steel cores at its two ends along the axial direction of the rotating shaft, which can effectively resist bending deformation of the rotating shaft.

[0039] A further technical solution also includes a rotor sleeve fixedly fitted onto the rotating shaft, a second pressure plate fixedly fitted onto the rotor sleeve, and both the second pressure plate and the rotor sleeve being in contact with the rotor core, such as in contact with a second magnetic steel core.

[0040] The second pressure plate can be heat-fitted onto the rotor pressure sleeve, and the rotor pressure sleeve can be interference-fitted with the shaft.

[0041] The pressure plate in this application can be made of aluminum alloy, and the pressure sleeve can be made of steel. The second pressure plate, in conjunction with the rotor pressure sleeve, can withstand a greater load and achieve stable axial positioning.

[0042] A further technical solution involves the weight-removing hole comprising a cylindrical section, the diameter of which is half the maximum diameter of the rotating shaft. For example, if the diameter of the rotating shaft is 110 mm, the diameter of the cylindrical section is 55 mm. This configuration balances the need to ensure the strength of the rotating shaft with the requirement to maximize the critical speed value.

[0043] A further technical solution involves a de-weighting hole penetrating one end of the rotating shaft to form the opening, with a plug at the opening to seal it. The de-weighting hole only needs to be formed at one end of the rotating shaft, which can adequately ensure the shaft's strength. This opening generally corresponds to a bearing position on the rotating shaft. By inserting the plug into the opening, the portion of the rotating shaft corresponding to the bearing position becomes a solid structure, improving the strength of the bearing position on the rotating shaft. The axial dimension of the plug is not limited.

[0044] Preferably, the opening is located near the second pressure plate.

[0045] A further technical solution involves the plug protruding outward relative to the opening along the axial direction of the rotating shaft. "Inward" refers to the direction towards the center of the rotating shaft, and "outward" refers to the direction from the center of the rotating shaft towards the opening.

[0046] The plug protrudes outward to form a machining section. By machining this section, it can be assembled with parts inside the motor, improving the utilization rate of the plug. For example, adding a contact point between the plug and the conductive ring can reduce shaft current corrosion of the bearing and improve bearing life.

[0047] The terms "first," "second," etc., used in this article do not specifically refer to order or sequence, nor are they intended to limit this case; they are merely used to distinguish components or operations described using the same technical terms.

[0048] The terms "connection" or "positioning" as used in this article can refer to two or more components or devices making direct physical contact with each other, or making indirect physical contact with each other, or to two or more components or devices operating or moving with each other.

[0049] The terms “include,” “including,” and “have” used in this article are all open-ended, meaning they include but are not limited to.

[0050] Unless otherwise specified, the terms used herein generally have their ordinary meaning in the context of the art, the subject matter, and the specific context. Certain terms used to describe this case will be discussed below or elsewhere in this specification to provide additional guidance to those skilled in the art in describing this case.

[0051] The terms “front,” “back,” “up,” “down,” “left,” and “right” used in this article are directional terms. In this case, they are only used to describe the positional relationship between the structures and are not intended to limit the specific direction of the protection scheme or its actual implementation.

[0052] The working principle and advantages of this invention are as follows:

[0053] The rotating shaft has a de-weighting hole that extends in the same direction as the shaft and is longer than half the length of the shaft, which can be considered as an excessive length. The de-weighting hole is coaxial with the rotating shaft, which allows for a larger cross-sectional size and a regular structure.

[0054] It should be noted that increasing the shaft diameter increases stiffness, and the higher the stiffness, the higher the critical speed. However, increasing the shaft diameter also increases its weight, resulting in a lower critical speed. To effectively increase the critical speed, the increase in shaft diameter should be accompanied by a smaller increase in weight. Therefore, at the same weight, a hollow shaft with a larger outer diameter (i.e., the shaft itself) will have better stiffness and a higher critical speed than a solid shaft with a smaller outer diameter. Based on this, a longer de-weighting hole can significantly reduce the weight of the shaft, ensuring an effective increase in the critical speed of a rotor with a thicker shaft. It also avoids the need to further thicken the shaft if the predetermined rotor critical speed threshold is not reached. The de-weighting hole is coaxial with the shaft, and its cross-sectional size can be larger, further ensuring a significant reduction in shaft weight.

[0055] It should also be noted that the deeper the de-balancing hole, the greater the degree of misalignment between the hole and the shaft due to factors such as actual machining precision. This makes it easier for the rotor's dynamic balance accuracy to deviate from the design requirements, resulting in significant eccentricity and an imbalance exceeding the allowable range. When the rotor rotates, the imbalance caused by eccentricity generates an inertial centrifugal force proportional to the square of the rotational speed. When the excitation frequency of this centrifugal force approaches the natural frequency of the rotor system, resonance is easily induced. When resonance occurs, the rotor's dynamic deflection increases significantly, reducing the system's equivalent stiffness. Consequently, the rotor is more likely to reach the critical speed within the operating speed range, exacerbating the vibration risk.

[0056] If the length of the de-balance hole is greater than half the length of the shaft, it can easily lead to deviations between the rotor's dynamic balance accuracy and design requirements. Therefore, de-balance is necessary. For the first pressure plate without a thickened area, due to its limited thickness, the weight reduction through drilling is limited, resulting in poor de-balance and failing to achieve the required dynamic balance accuracy. By adding an additional thickened layer with a thickness consistent with the main body of the first pressure plate, the weight reduction through drilling is increased, making it easier to bring the rotor's dynamic balance accuracy closer to the design requirements. This helps to address the issue of the rotor's critical speed decreasing due to dynamic balance deviations.

[0057] The length of the weight-removing hole is greater than half the length of the shaft, and the hole is formed on the end face of the shaft near the second pressure plate. That is, the weight-removing hole is formed by opening from the end of the shaft near the second pressure plate. The deeper the weight-removing hole goes, the greater the eccentricity between the area of ​​the weight-removing hole and the shaft, and the greater the imbalance. Therefore, a thickened layer is provided on the first pressure plate, while no thickened layer is needed on the second pressure plate to control the rotor weight and cost. Controlling the rotor weight is beneficial for achieving rotor lightweighting and improving product competitiveness.

[0058] The thickened layer is formed on the pressure plate body in the area near the outer ring, but not simultaneously in the area near the inner ring. This can achieve the purpose of weight reduction to adjust the dynamic balance accuracy of the rotor, and also avoid adding ineffective structures, thus controlling the rotor weight and cost. Attached Figure Description

[0059] Appendix Figure 1 This is a schematic diagram of the rotor structure for increasing the critical speed of the rotor according to an embodiment of the present invention;

[0060] Appendix Figure 2 This is a schematic diagram of the structure of the rotating shaft and the plug in an embodiment of the present invention;

[0061] Appendix Figure 3 This is a schematic diagram of the structure of the first pressure plate in an embodiment of the present invention;

[0062] Appendix Figure 4 This is a cross-sectional view of the first pressure plate in an embodiment of the present invention;

[0063] Appendix Figure 5 This is a schematic diagram of the structure of the second pressure plate in an embodiment of the present invention;

[0064] Appendix Figure 6 This is a cross-sectional view of a rotor structure for increasing the critical speed of the rotor according to an embodiment of the present invention (the rotor is not fully assembled).

[0065] In the attached diagrams above: 1. Rotating shaft; 11. Weight removal hole; 111. Opening; 112. Cylindrical section;

[0066] 2. Rotor core; 21. First magnetized steel core; 22. Second magnetized steel core;

[0067] 3. Rotor pressure plate; 31. First pressure plate; 311. Pressure plate body; 312. Thickened layer; 32. Second pressure plate;

[0068] 4. Separator; 41. Third pressure plate; 42. Intermediate pressure sleeve; 43. Fourth pressure plate;

[0069] 5. Rotor sleeve; 6. Plug; 61. Machining section. Detailed Implementation

[0070] The present invention will be further described below with reference to the accompanying drawings and embodiments:

[0071] Example: The present invention will be clearly described below with illustrations and detailed description. Any person skilled in the art who understands the examples of the present invention can make changes and modifications based on the technology taught in the present invention without departing from the spirit and scope of the present invention.

[0072] The terminology used herein is for the purpose of describing specific embodiments only and is not intended to limit the scope of this work. Singular forms such as “a,” “this,” “this,” “the,” and “the” as used herein also include plural forms.

[0073] See appendix Figure 1 -Appendix Figure 6 A rotor structure for increasing the critical speed of a rotor includes a rotating shaft 1 and a rotor core 2 and a rotor pressure plate 3, both of which are fixedly sleeved and assembled on the rotating shaft 1.

[0074] The rotating shaft 1 is provided with a weight-removing hole 11;

[0075] The rotor pressure plate 3 includes a first pressure plate 31 and a second pressure plate 32 respectively disposed at both ends of the rotor core 2;

[0076] The weight removal hole 11 extends in the same direction as the rotating shaft 1 and is coaxially arranged; the length of the weight removal hole 11 is greater than half the length of the rotating shaft 1; the weight removal hole 11 has an opening 111 formed on the end face of the rotating shaft 1 near the second pressure plate 32;

[0077] The first pressure plate 31 includes a pressure plate body 311 and a thickening layer 312 connected to each other. The thickening layer 312 is located on the side of the pressure plate body 311 away from the second pressure plate 32. The thickening layer 312 is formed on the area of ​​the pressure plate body 311 near the outer ring. The thickness of the pressure plate body 311, the thickening layer 312 and the second pressure plate 32 is the same.

[0078] The rotor structure is configured such that the opening 111 of the weight removal hole 11 faces the second pressure plate 32, and the length of the weight removal hole 11 is greater than half the length of the shaft 1. Combined with the provision of the thickening layer 312 on the first pressure plate 31, and the arrangement that the thickness of the pressure plate body 311, the thickening layer 312 and the second pressure plate 32 are the same, the rotor structure has a set rotor critical speed value. Under the set rotor critical speed value, the rotor dynamic balance state of the rotor structure in the direction close to the first pressure plate 31 tends to be stable.

[0079] The assembly of the shaft 1, rotor core 2, and rotor pressure plate 3 is a standard setup and will not be described in detail here. The rotor pressure plate 3 can position the rotor core 2, which is its current purpose and will not be described in detail here.

[0080] The rotating shaft 1 is provided with a de-weighting hole 11. The de-weighting hole 11 extends in the same direction as the rotating shaft 1 and its length is greater than half the length of the rotating shaft 1, which can be regarded as its length being relatively long. The de-weighting hole 11 is coaxially arranged with the rotating shaft 1, which allows the cross-sectional size of the de-weighting hole 11 to be relatively large and to have a regular structure.

[0081] It should be noted that increasing the diameter of shaft 1 increases stiffness, and the higher the stiffness, the higher the critical speed. However, increasing the diameter of shaft 1 also increases its weight, resulting in a lower critical speed. To ensure an effective increase in the critical speed, the increase in shaft 1 diameter should be accompanied by a smaller increase in weight. In this case, for the same weight, a hollow shaft with a larger outer diameter (i.e., shaft 1) will have better stiffness and a higher critical speed than a solid shaft with a smaller outer diameter. Based on this, the relatively long de-weighting hole 11 can significantly reduce the weight of shaft 1, ensuring an effective increase in the critical speed of the rotor with a thicker shaft 1. It also avoids the need to further thicken shaft 1 if the predetermined rotor critical speed threshold is not reached. The de-weighting hole 11 is coaxial with shaft 1, and its cross-sectional dimensions can be relatively large, further ensuring a significant reduction in the weight of shaft 1.

[0082] It should also be noted that the deeper the de-balancing hole 11, the greater the degree of misalignment between the de-balancing hole 11 and the shaft 1 due to factors such as actual machining accuracy. This makes it easier for the rotor's dynamic balance accuracy to deviate from the design requirements, resulting in significant eccentricity and causing the imbalance to exceed the allowable range. When the rotor rotates, the imbalance caused by eccentricity generates an inertial centrifugal force proportional to the square of the rotational speed. When the excitation frequency of this centrifugal force is close to the natural frequency of the rotor system, resonance is easily induced. When resonance occurs, the rotor's dynamic deflection increases significantly, reducing the system's equivalent stiffness. Consequently, the rotor is more likely to reach the critical speed within the operating speed range, exacerbating the vibration risk.

[0083] The length of the weight-reduction hole 11 is greater than half the length of the shaft 1, which can easily lead to deviations between the rotor's dynamic balance accuracy and design requirements. Therefore, weight reduction is necessary. For the first pressure plate 31 without a thickened area, due to its limited thickness, the weight reduction achieved through drilling is limited, resulting in a poor weight reduction effect and failing to achieve the required dynamic balance accuracy. By adding an additional thickened layer 312, whose thickness is consistent with the main body 311 of the first pressure plate 31, the weight reduction possible through drilling is increased, making it easier to bring the rotor's dynamic balance accuracy closer to the design requirements. This helps to address the problem of the rotor's critical speed decreasing due to dynamic balance accuracy deviations.

[0084] The length of the de-weighting hole 11 is greater than half the length of the rotating shaft 1, and the de-weighting hole 11 has an opening 111 formed on the end face of the rotating shaft 1 near the second pressure plate 32. That is, the de-weighting hole 11 is formed by opening from the end of the rotating shaft 1 near the second pressure plate 32. At this time, the deeper the de-weighting hole 11 is, the greater the eccentricity between the area on the de-weighting hole 11 and the rotating shaft 1, and the greater the imbalance. Therefore, a thickening layer 312 is provided on the first pressure plate 31, while the thickening layer 312 can be omitted on the second pressure plate 32 to control the rotor weight and cost. Controlling the rotor weight is beneficial to achieving rotor lightweighting and improving product competitiveness.

[0085] In some embodiments, a thickened area may be provided on the second pressure plate 32.

[0086] The thickened layer 312 is formed on the pressure plate body 311 in the area near the outer ring, but not simultaneously in the area near the inner ring. This achieves the purpose of weight reduction to adjust the dynamic balance accuracy of the rotor, and also avoids adding unnecessary structures, thus controlling the rotor weight and cost. In the axial direction of the shaft 1, the orthographic projection of the thickened layer 312 can coincide with the orthographic projection of the area near the outer ring on the pressure plate body 311.

[0087] See appendix Figure 1 In this embodiment, the rotor core 2 includes a first magnetic steel core 21 and a second magnetic steel core 22, both sleeved and assembled on the rotating shaft 1; the first magnetic steel core 21 is attached to the pressure plate body 311, and the second magnetic steel core 22 is attached to the second pressure plate 32; a separator 4 sleeved and assembled on the rotating shaft 1 is provided between the first magnetic steel core 21 and the second magnetic steel core 22.

[0088] The rotor core 2 has magnets, and the first magnetized iron core 21 and the second magnetized iron core 22 are separated by the separator 4. The first magnetized iron core 21 and the second magnetized iron core 22 can be regarded as the main drive and the auxiliary drive, respectively. Under normal working conditions, only the main drive runs, and the main and auxiliary drives work together when there is a large torque requirement.

[0089] Preferably, the first magnetized steel core 21 and the second magnetized steel core 22 are symmetrically arranged in the axial direction of the rotating shaft 1.

[0090] The assembly method of the iron core structure and the rotating shaft 1 is existing and will not be described in detail here.

[0091] See appendix Figure 6 In this embodiment, the separator 4 includes:

[0092] The third pressure plate 41 is sleeved and assembled on the rotating shaft 1 and attached to the first magnetic steel core 21;

[0093] The intermediate pressure sleeve 42 is fitted onto the rotating shaft 1 and attached to the third pressure plate 41;

[0094] The fourth pressure plate 43 is sleeved and assembled on the rotating shaft 1 and attached to the second magnetic steel core 22 and the intermediate pressure sleeve 42;

[0095] The third pressure plate 41, the intermediate pressure sleeve 42 and the fourth pressure plate 43 are all relatively fixed to the rotating shaft 1;

[0096] Both the third pressure plate 41 and the fourth pressure plate 43 are non-magnetic structures.

[0097] The intermediate pressure sleeve 42 controls the distance between the first magnetic steel core 21 and the second magnetic steel core 22. Located in the central region along the axial direction of the rotating shaft 1, the intermediate pressure sleeve 42 enhances the bending stiffness of the central region of the rotating shaft 1, thereby reducing the bending deflection of the rotating shaft 1 under load. The smaller the deflection, the stronger the resistance of the rotating shaft 1 to bending deformation. Under the premise that the support form and mass distribution remain unchanged, the critical speed of the rotating shaft 1 will also increase accordingly, making resonance less likely. The intermediate pressure sleeve 42 can be made of steel.

[0098] The third pressure plate 41 and the fourth pressure plate 43 can be made of aluminum. Neither of them is magnetic, which blocks the magnetic circuit connection between the first magnetic steel core 21 and the second magnetic steel core 22, thus preventing the motor torque output from becoming lower and making them lighter in weight.

[0099] See appendix Figure 6 In this embodiment, the third pressure plate 41 and the fourth pressure plate 43 are respectively fixedly sleeved on both ends of the intermediate pressure sleeve 42 in the axial direction of the rotating shaft 1. The two ends of the intermediate pressure sleeve 42 in the axial direction of the rotating shaft 1 are respectively attached to the first magnetic steel core 21 and the second magnetic steel core 22. The intermediate pressure sleeve 42 is interference-fitted with the rotating shaft 1.

[0100] The third pressure plate 41 and the fourth pressure plate 43 can be heat-fitted onto the intermediate pressure sleeve 42 to achieve fixation. Afterwards, only an interference fit between the intermediate pressure sleeve 42 and the rotating shaft 1 is required, facilitating the installation of all three components and improving rotor assembly efficiency. At this point, the third pressure plate 41, the fourth pressure plate 43, and the intermediate pressure sleeve 42 can be considered as a single integrated structure. This design effectively ensures the achievement of the aforementioned effect of enhancing the bending stiffness of the central region of the rotating shaft 1.

[0101] Taking the intermediate pressure sleeve 42 as an example, the intermediate pressure sleeve 42 can position the first magnetic steel core 21 and the second magnetic steel core 22 in the axial direction of the rotating shaft 1.

[0102] Preferably, the third pressure plate 41 and the fourth pressure plate 43 are symmetrically arranged in the axial direction of the rotating shaft 1. They can be symmetrically arranged based on a symmetrical plane that passes through the center point of the rotating shaft 1 and is perpendicular to the axis of the rotating shaft 1.

[0103] The intermediate pressure sleeve 42 is attached to the first magnetic steel core 21 and the second magnetic steel core 22 at its two ends in the axial direction of the rotating shaft 1, which can effectively resist bending deformation of the rotating shaft 1.

[0104] See appendix Figure 6 In this embodiment, a rotor sleeve 5 is fixedly fitted onto the rotating shaft 1, and a second pressure plate 32 is fixedly fitted onto the rotor sleeve 5. Both the second pressure plate 32 and the rotor sleeve 5 are attached to the rotor core 2, such as to the second magnetic steel core 22.

[0105] The second pressure plate 32 can be heat-fitted onto the rotor pressure sleeve 5, and the rotor pressure sleeve 5 can be interference-fitted with the rotating shaft 1.

[0106] In this embodiment, the pressure plate can be made of aluminum alloy, and the pressure sleeve can be made of steel. The second pressure plate 32 cooperates with the rotor pressure sleeve 5 to withstand a larger load and achieve stable axial positioning.

[0107] See appendix Figure 2 In this embodiment, the weight-removing hole 11 includes a cylindrical section 112, the diameter of which is half the maximum diameter of the rotating shaft 1. For example, if the maximum diameter of the rotating shaft 1 is 110 mm, the diameter of the cylindrical section 112 is 55 mm. Based on this setting, the need to ensure the strength of the rotating shaft 1 and to maximize the critical speed value can be balanced. The maximum diameter of the rotating shaft 1 can be understood as the diameter of the main cylindrical region on the rotating shaft 1, which is conventional and well known to those skilled in the art, and will not be elaborated here.

[0108] See appendix Figure 2 In this embodiment, the de-weighting hole 11 penetrates one end of the rotating shaft 1 to form the opening 111, and a plug 6 is provided at the opening 111 to seal it. The de-weighting hole 11 only needs to form an opening 111 at one end of the rotating shaft 1, which can adequately ensure the strength of the rotating shaft 1. This opening 111 generally corresponds to a bearing position on the rotating shaft 1. By inserting the plug 6 into the opening 111, the portion of the rotating shaft 1 corresponding to the bearing position becomes a solid structure, improving the strength of the bearing position on the rotating shaft 1. The axial dimension of the plug 6 is not limited.

[0109] Preferably, the opening 111 is located near the second pressure plate 32.

[0110] See appendix Figure 2 In this embodiment, the plug 6 protrudes outward relative to the opening 111 along the axial direction of the rotating shaft 1. "Inward" refers to the direction towards the center of the rotating shaft 1, and "outward" refers to the direction from the center of the rotating shaft 1 towards the opening 111.

[0111] The plug 6 protrudes outward to form a machining section 61. By machining this machining section 61, it can be assembled with parts inside the motor, improving the utilization rate of the plug 6. For example, adding a contact point with the conductive ring on the plug 6 can reduce the corrosion of the bearing by shaft current and improve the bearing life.

[0112] The above embodiments are only for illustrating the technical concept and features of the present invention, and are intended to enable those skilled in the art to understand the content of the present invention and implement it accordingly. They should not be construed as limiting the scope of protection of the present invention. All equivalent changes or modifications made in accordance with the spirit and essence of the present invention should be covered within the scope of protection of the present invention.

Claims

1. A rotor structure for increasing the critical speed of a rotor, characterized in that: It includes a rotating shaft (1) and a rotor core (2) and a rotor pressure plate (3) that are fixedly sleeved and assembled on the rotating shaft (1). The rotating shaft (1) is provided with a weight-removing hole (11). The rotor pressure plate (3) includes a first pressure plate (31) and a second pressure plate (32) respectively disposed at both ends of the rotor core (2). The weight removal hole (11) extends in the same direction and is coaxially arranged with the rotating shaft (1); the length of the weight removal hole (11) is greater than half the length of the rotating shaft (1); the weight removal hole (11) has an opening (111) formed on the end face of the rotating shaft (1) near the second pressure plate (32). The first pressure plate (31) includes a pressure plate body (311) and a thickening layer (312) connected to each other. The thickening layer (312) is located on the side of the pressure plate body (311) away from the second pressure plate (32). The thickening layer (312) is formed on the area of ​​the pressure plate body (311) near the outer ring. The thickness of the pressure plate body (311), the thickening layer (312) and the second pressure plate (32) are the same. The rotor structure is configured such that the opening (111) of the weight removal hole (11) faces the second pressure plate (32), and the length of the weight removal hole (11) is greater than half the length of the shaft (1). Combined with the thickening layer (312) provided on the first pressure plate (31) and the thickness of the pressure plate body (311), the thickening layer (312) and the second pressure plate (32) being the same, the rotor structure has a set rotor critical speed value. Under the set rotor critical speed value, the rotor dynamic balance state of the rotor structure in the direction close to the first pressure plate (31) tends to be stable.

2. The rotor structure for increasing the critical speed of a rotor according to claim 1, characterized in that: The rotor core (2) includes a first magnetic steel core (21) and a second magnetic steel core (22) both sleeved and assembled on the rotating shaft (1); the first magnetic steel core (21) is attached to the pressure plate body (311), and the second magnetic steel core (22) is attached to the second pressure plate (32); a separator (4) sleeved and assembled on the rotating shaft (1) is provided between the first magnetic steel core (21) and the second magnetic steel core (22).

3. The rotor structure for increasing the critical speed of a rotor according to claim 2, characterized in that: The separator (4) includes: The third pressure plate (41) is sleeved and assembled on the rotating shaft (1) and attached to the first magnetic steel core (21). The intermediate pressure sleeve (42) is fitted onto the rotating shaft (1) and attached to the third pressure plate (41). The fourth pressure plate (43) is sleeved and assembled on the rotating shaft (1) and attached to the second magnetic steel core (22) and the intermediate pressure sleeve (42). The third pressure plate (41), the intermediate pressure sleeve (42) and the fourth pressure plate (43) are all relatively fixed to the rotating shaft (1); Both the third pressure plate (41) and the fourth pressure plate (43) are non-magnetic structures.

4. The rotor structure for increasing the critical speed of a rotor according to claim 3, characterized in that: The third pressure plate (41) and the fourth pressure plate (43) are respectively fixedly sleeved on both ends of the intermediate pressure sleeve (42) on the axial direction of the rotating shaft (1). The two ends of the intermediate pressure sleeve (42) on the axial direction of the rotating shaft (1) are respectively attached to the first magnetic steel core (21) and the second magnetic steel core (22). The intermediate pressure sleeve (42) and the rotating shaft (1) are interference fit.

5. A rotor structure for increasing the critical speed of a rotor according to any one of claims 1-4, characterized in that: It also includes a rotor sleeve (5) fixedly fitted onto the rotating shaft (1), and a second pressure plate (32) fixedly fitted onto the rotor sleeve (5). The second pressure plate (32) and the rotor sleeve (5) are both attached to the rotor core (2).

6. A rotor structure for increasing the critical speed of a rotor according to any one of claims 1-4, characterized in that: The weight removal hole (11) includes a cylindrical section (112) with a diameter that is half the maximum diameter of the rotating shaft (1).

7. A rotor structure for increasing the critical speed of a rotor according to any one of claims 1-4, characterized in that: The weight removal hole (11) passes through one end of the rotating shaft (1) to form the opening (111), and a plug (6) is provided at the opening (111) to seal the opening (111).

8. The rotor structure for increasing the critical speed of a rotor according to claim 7, characterized in that: In the axial direction of the rotating shaft (1), the plug (6) is arranged to protrude outward relative to the opening (111).

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