A large vertical machine tool working turntable direct drive permanent magnet driving motor rotor

Abstract

The application belongs to the technical field of electric machines, and particularly relates to a large vertical machine tool working turntable direct-drive permanent magnet driving motor rotor, characterized in that the rotor comprises a magnetic steel rotor, a rotor yoke and a cross roller bearing outer ring; the magnetic steel rotor is fixedly connected with the rotor yoke to form a rotating main body; the outer ring of the cross roller bearing is fixedly connected with the rotor yoke, so that the outer ring of the cross roller bearing rotates together with the rotating main body; the inner ring of the cross roller bearing is fixedly connected with a stator base of the motor, and the inner ring remains stationary; the rotating main body is integrally configured to adapt to an oil immersion cooling environment and has oil-resistant and rust-proof performance; wherein the rated radial dynamic load of the cross roller bearing is greater than or equal to 27T, and the rated axial dynamic load is greater than or equal to 34.4T.

Description

Technical Field

[0001] This utility model belongs to the field of motor technology, specifically relating to a rotor of a direct-drive permanent magnet drive motor for a large vertical machine tool turntable. Background Technology

[0002] Currently, the rotary table drive of large vertical machine tools (such as heavy-duty vertical lathes and gantry milling machines) mostly adopts an indirect transmission mode of "motor + reducer + gear", or uses a traditional high-speed internal rotor motor with conventional rolling bearings. The rotor of the traditional motor is mostly a slender shaft structure, supported by two sets of deep groove ball bearings or tapered roller bearings at the front and rear, with the outer ring of the bearing fixed in the bearing housing of the end cover. Under low-speed and heavy-load conditions, this structure is difficult to withstand huge radial cutting forces and axial overturning moments due to the limitation of the rated dynamic load of the bearings. Moreover, the long shaft structure results in poor rigidity, which easily leads to vibration and deformation, affecting machining accuracy.

[0003] However, the aforementioned traditional structures have significant drawbacks: First, insufficient load-bearing capacity; conventional bearings cannot provide radial dynamic loads exceeding 27T and axial dynamic loads exceeding 34T, limiting the machine tool's ability to process heavy workpieces weighing 10 tons or more. Second, low transmission accuracy; multi-stage transmission chains introduce backlash and errors, making it difficult to meet high-precision machining requirements. Third, poor environmental adaptability; large machine tools often use oil immersion cooling to reduce temperature rise, and traditional motor rotors are difficult to seal and prone to corrosion. Fourth, poor noise and stability; the slender shaft has a low resonance frequency and high operating noise. Therefore, there is an urgent need for a high-power direct-drive motor rotor that can directly withstand ultra-large loads, has a compact structure, high rigidity, and is adaptable to oil immersion environments. Utility Model Content

[0004] This utility model discloses a direct-drive permanent magnet drive motor rotor for a large vertical machine tool turntable, which mainly solves the problems that traditional rotors cannot withstand ultra-large loads, lack high rigidity, and are not suitable for oil immersion environments.

[0005] To achieve the aforementioned objective, this utility model provides a direct-drive permanent magnet drive motor rotor for a large vertical machine tool turntable, comprising a magnet rotor, a rotor yoke, and an outer ring of a crossed roller bearing. The magnetic steel rotor is fixedly connected to the rotor yoke to form a rotating body; The outer ring of the crossed roller bearing is fixedly connected to the rotor yoke, so that the outer ring of the crossed roller bearing rotates together with the rotating body; The inner ring of the crossed roller bearing is fixedly connected to the stator housing of the motor, and the inner ring remains stationary. The rotating main body is configured to be suitable for an oil-immersion cooling environment and has oil resistance and rust prevention properties. The rated radial dynamic load of the crossed roller bearing is ≥27T, and the rated axial dynamic load is ≥34.4T.

[0006] Preferably, the outer ring of the crossed roller bearing is fixedly connected to the end face or outer peripheral surface of the rotor yoke by means of interference fit, key connection or welding.

[0007] Preferably, the magnet rotor has a disc-shaped or multi-pole disc structure, with magnets arranged alternately along the circumference to directly generate large torque output without a speed reduction mechanism.

[0008] Preferably, the rotor yoke and the surface of the magnet rotor are coated with an oil-resistant and corrosion-resistant coating, or are made of stainless steel, to be compatible with the oil-immersed cooling medium in the stator cavity.

[0009] Preferably, a rotary table drive system is used in large vertical machining centers that process workpieces weighing more than 10 tons.

[0010] Preferably, the crossed roller bearing is a double-row crossed roller bearing with cylindrical or spherical roller cross sections, and the bearing width is adapted to high axial load requirements.

[0011] The technical solution provided by this utility model has at least the following technical effects: High load capacity and high rigidity: This innovative design integrates the outer ring of the crossed roller bearing with the rotor, utilizing the cross roller bearing's inherently high radial (27T) and axial (34.4T) dynamic load capacity to directly replace the traditional dual-bearing support scheme. This "single-point high load capacity" structure eliminates long-axis deflection, significantly improving the system's torsional stiffness and anti-overturning capability, ensuring high precision even when machining workpieces weighing over 10 tons.

[0012] Direct drive for high efficiency and high precision: It adopts a disc-type multi-pole permanent magnet motor direct drive structure, which eliminates intermediate transmission links such as reducers and gears, realizes zero backlash transmission, significantly improves positioning accuracy and repeatability, and reduces mechanical loss and noise, resulting in smoother operation.

[0013] Strong environmental adaptability: The rotor's overall design is adapted to oil-immersion cooling environments. Through oil-resistant and rust-proof treatments (such as special coatings or materials), the insulation degradation and corrosion problems of large motors in oil-cooled environments are solved, extending the equipment's lifespan.

[0014] Compact structure and easy maintenance: The single set of crossed roller bearings integrates radial and axial support functions, which simplifies the axial structure of the motor, reduces the overall size of the machine, and facilitates maintenance. Attached Figure Description

[0015] To more clearly illustrate the technical solutions in the embodiments of this utility model, 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 this utility model. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0016] Figure 1 This is a schematic diagram of the structure of an embodiment of the present utility model; Key reference numerals in the attached drawings: 1. Magnet rotor; 2. Crossed roller bearing; 3. Rotor yoke; 4. Locking screw for magnet baffle; 5. Magnet baffle; 6. Magnet; 7. Magnetic shielding plate; 8. Working turntable; 9. Rotor and bearing outer ring cover; 10. Encoder cover; 11. Encoder locking plate; Detailed Implementation The embodiments of this utility model are described in detail below. Examples of the embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and intended to explain the embodiments of this utility model, and should not be construed as limiting the utility model.

[0017] In the description of the embodiments of this utility model, it should be understood that the terms "length", "width", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings. They are only for the convenience of describing the embodiments of this utility model and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this utility model.

[0018] 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 indicated technical features. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of the stated features. In the description of the embodiments of this utility model, "a plurality of" means two or more, unless otherwise explicitly specified.

[0019] Please refer to Figure 1This utility model provides a direct-drive permanent magnet drive motor rotor for a large vertical machine tool turntable, including a magnet 6 rotor 1, a rotor yoke 3, and a crossed roller bearing 2 outer ring; the magnet 6 rotor 1 and the rotor yoke 3 are fixedly connected to form a rotating body; the outer ring of the crossed roller bearing 2 is fixedly connected to the rotor yoke 3, so that the outer ring of the crossed roller bearing 2 rotates together with the rotating body; the inner ring of the crossed roller bearing 2 is fixedly connected to the stator seat of the motor, and the inner ring remains stationary; the rotating body is configured to be suitable for an oil immersion cooling environment and has oil resistance and rust prevention performance; wherein, the rated radial dynamic load of the crossed roller bearing 2 is ≥27T, and the rated axial dynamic load is ≥34.4T. In this embodiment, the rotor 1 with magnet 6 adopts high-performance neodymium iron boron magnet 6 (grade N48SH), which is arranged alternately in a multi-pole disk structure along the circumferential direction to directly generate large torque; the rotor yoke 3 adopts high-strength alloy structural steel (such as 35CrMoA), which is quenched and tempered to achieve a hardness of HRC28-32, and the surface is carburized and quenched to improve wear resistance. The crossed roller bearing 2 is selected from heavy-duty series (such as FAG XLS series or KOYO RBC series). Its outer ring is press-fitted into the annular groove on the end face of the rotor yoke 3 with an interference fit (tolerance grade P6), and is supplemented with a key connection to prevent relative rotation and ensure that the outer ring rotates synchronously with the rotor. The inner ring of the bearing is fixed in the bearing chamber hole of the stator housing by set screws and remains stationary. The entire rotor is coated with a Teflon (PTFE) oil-resistant and corrosion-resistant coating with a thickness of 50μm to adapt to the cooling environment of cutting fluid or lubricating oil in the stator cavity. The working principle is as follows: the stator generates a rotating magnetic field when energized, which drives the disc rotor to rotate. Since the outer ring of the crossed roller bearing 2 rotates with the rotor and the inner ring is fixed, the bearing directly bears all the radial cutting force and axial overturning moment of the rotor. Utilizing its extremely high dynamic load-bearing capacity (radial 27T, axial 34.4T), it ensures the rigidity and accuracy of the system when machining workpieces weighing more than 10 tons. The oil-immersed cooling medium directly contacts the rotor surface, removes heat, and improves the motor's heat dissipation efficiency. This implementation method completely solves the problems of poor rigidity and low load-bearing capacity of traditional long shaft structures through its unique "outer ring follow-up" structure and heavy-duty bearing selection.

[0020] The outer ring of the crossed roller bearing 2 is fixedly connected to the end face or outer circumferential surface of the rotor yoke 3 by interference fit, key connection, or welding. In this embodiment, the end face of the rotor yoke 3 is designed with a precision-machined annular stop. The inner diameter of the bearing outer ring and the outer diameter of the rotor yoke 3 adopt an H7 / p6 interference fit with an interference amount of 0.05mm-0.08mm to ensure initial tightening force. At the same time, a rectangular keyway is opened on the mating surface, and a high-strength stainless steel flat key (size 10mm×10mm) is embedded therein to transmit part of the torque and prevent fretting wear. For ultra-large specifications, high-temperature alloy welds can also be used for circumferential welding reinforcement. In practical applications, the connection method can also be selected by heat fitting and bolt locking according to specific working conditions. This embodiment does not limit this. This implementation method ensures absolute synchronization between the outer ring and the rotor under extreme loads through multiple connection methods (interference fit + key / welding), eliminates the risk of slippage at the connection interface, and significantly improves the reliability and lifespan of the system.

[0021] The rotor yoke 3 and the magnet 6 rotor 1 are coated with an oil-resistant and corrosion-resistant coating, or are made of stainless steel to accommodate the oil-immersion cooling medium in the stator cavity. In this embodiment, the rotor yoke 3 is integrally forged from 304L stainless steel, which has excellent corrosion resistance; the magnet 6 rotor 1 is wrapped with a 2mm thick stainless steel sheath (SUS316) and sealed by epoxy resin potting process to completely isolate the cutting fluid from contact; or, a three-layer composite coating is sprayed onto the surface of a common carbon steel rotor: the bottom layer is epoxy zinc-rich primer (dry film thickness 50μm), the middle layer is polyurethane intermediate coating (dry film thickness 80μm), and the top layer is polytetrafluoroethylene oil-resistant topcoat (dry film thickness 50μm). In practical applications, the coating material can also be modified silicone resin or ceramic coating, as long as it meets the requirements of oil resistance, high temperature resistance (>100℃) and insulation. This embodiment does not limit this. This implementation completely solves the corrosion and insulation hazards in the oil immersion environment through material upgrades or special coating technology, ensuring the long-term stable operation of the motor under harsh conditions.

[0022] In this embodiment, the selected crossed roller bearing 2 is a double-row, four-row roller structure (V-type or O-type arrangement). The rollers are made of high-carbon chromium bearing steel (GCr15) and undergo vacuum degassing treatment to improve purity. The bearing width is designed to be 1.5 to 2 times that of conventional models to increase contact area and load-bearing capacity. The bearing clearance is precisely adjusted, and the preload is set to 15%-20% of the rated dynamic load to eliminate backlash and improve positioning accuracy. Actual test data shows that under a 27T radial load and a 34.4T axial load, the bearing's elastic deformation is less than 0.02mm, fully meeting the requirements of high-precision machining. In practical applications, the bearing model can be customized according to the specific load spectrum, such as increasing the number of rollers or optimizing the raceway curvature radius; this embodiment does not limit this. This implementation, through the selection of heavy-duty bearings and optimization of geometric parameters, ensures the system's ultra-high rigidity and long service life across the entire load range, meeting the core requirements of heavy-duty machining.

[0023] In this embodiment, the motor has more than 60 poles, a pole arc coefficient of 0.9, and the cogging torque is reduced to below 0.5% through skewed pole optimization. The rotor is directly mounted at the center of the turntable without any gearbox or pulleys, achieving a 1:1 transmission ratio. The control system uses a high-resolution encoder (0.001° resolution) with closed-loop control to achieve micron-level positioning. Actual tests show that this direct-drive system eliminates mechanical transmission backlash, achieving a repeatability of ±0.5μm, far exceeding traditional systems with reducers (typically ±5-10μm). In practical applications, the disc structure can also be designed as a hollow shaft to accommodate cables or pipes; this embodiment does not limit this. This implementation, through its direct-drive architecture, significantly simplifies the mechanical structure, reduces failure points, and substantially improves transmission efficiency and positioning accuracy, making it particularly suitable for high-precision heavy-duty machining scenarios.

[0024] The above are merely preferred embodiments of the present utility model and are not intended to limit the present utility model. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present utility model should be included within the protection scope of the present utility model.

Claims

1. A rotor for a direct-drive permanent magnet motor for a large vertical machine tool turntable, characterized in that, It includes a magnet (6) rotor (1), a rotor yoke (3), and an outer ring of a crossed roller bearing (2); The magnet (6) rotor (1) and the rotor yoke (3) are fixedly connected to form a rotating body; The outer ring of the crossed roller bearing (2) is fixedly connected to the rotor yoke (3), so that the outer ring of the crossed roller bearing (2) rotates together with the rotating body; The inner ring of the crossed roller bearing (2) is fixedly connected to the stator of the motor, and the inner ring remains stationary; The rotating main body is configured to be suitable for an oil-immersion cooling environment and has oil resistance and rust prevention properties. The rated radial dynamic load of the crossed roller bearing (2) is ≥27T, and the rated axial dynamic load is ≥34.4T.

2. The rotor of the direct-drive permanent magnet drive motor for the large vertical machine tool turntable according to claim 1, characterized in that: The outer ring of the crossed roller bearing (2) is fixedly connected to the end face or outer peripheral surface of the rotor yoke (3) by interference fit, key connection or welding.

3. The rotor of the direct-drive permanent magnet drive motor for the large vertical machine tool turntable according to claim 1, characterized in that: The magnet (6) rotor (1) has a disc-shaped or multi-pole disc structure, and the magnets (6) are arranged alternately along the circumference to directly generate large torque output without a speed reduction mechanism.

4. The rotor of the direct-drive permanent magnet drive motor for the large vertical machine tool turntable according to claim 1, characterized in that: The rotor yoke (3) and magnet (6) are coated with an oil-resistant and corrosion-resistant coating or made of stainless steel to accommodate the oil-immersed cooling medium in the stator cavity.

5. The rotor of the direct-drive permanent magnet motor for the large vertical machine tool turntable according to any one of claims 1-4, characterized in that: A rotary table drive system for large vertical machining centers that process workpieces weighing more than 10 tons.

6. The rotor of the direct-drive permanent magnet drive motor for the large vertical machine tool turntable according to claim 1, characterized in that: The crossed roller bearing (2) is a double-row crossed roller bearing (2), the roller cross section is cylindrical or spherical, and the bearing width is adapted to high axial load requirements.

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