An integrated magnetic field drive and rolling support one-piece motor bearing structure

Abstract

The utility model discloses an integrated magnetic field drive and rolling support integrated motor bearing structure, including the casing and the rotating shaft of being located in the casing, the outer periphery of rotating shaft middle part is equipped with annular recess, the recess upper and lower wall fixedly equipped with the magnetic field response part that is composed of the S pole and N pole permanent magnet of circumferential alternate arrangement, the flange fixed end of casing is fixedly connected with the recess, and the coil assembly that is opposite with permanent magnet array and has the clearance is built -in and is used as the magnetic field generating part. The recess and the clearance of flange fixed end gap are equipped with the rolling friction structure, including the first rolling friction structure of recess lateral wall and the second rolling friction structure of rotating shaft central axis. The structure realizes direct drive through magnetic field coupling, and the intermediate transmission link is saved, and the transmission efficiency, axial and radial limit precision and rotational speed adaptability are improved significantly in combination with the design of hierarchical rolling support, and the space occupation and maintenance cost are reduced, and it is suitable for high -precision five -axis turntable and other precision equipment.

Description

Technical Field

[0001] This application relates to the field of motor bearing technology, and more specifically, to an integrated motor bearing structure that integrates magnetic field drive and rolling support, which is particularly suitable for precision mechanical equipment (such as five-axis rotary tables, precision machine tool spindles, etc.) with stringent requirements for transmission accuracy, speed adaptability and operational stability. Background Technology

[0002] In precision manufacturing, aerospace and other fields, five-axis rotary tables are core processing and testing equipment, and the driving and support performance of their rotary axes directly determines the overall accuracy of the equipment. At present, the rotary axis drive and support of five-axis rotary tables mostly adopt a split design of "independent motor and mechanical bearing", that is, the rotational power is provided by a servo motor, and the radial and axial limits of the rotary axis are achieved by ball bearings or sliding bearings.

[0003] However, this traditional structure has significant drawbacks: power needs to be transmitted to the rotating shaft through intermediate components such as couplings and reduction gears. The multi-stage contact not only leads to transmission efficiency loss (typically 8%-15%), but also easily introduces additional vibration due to assembly errors, reducing the positioning accuracy of the turntable (radial runout often exceeds 0.01mm); secondly, the split layout requires separate installation space for the motor and bearings, making it difficult to meet the design trend of miniaturization and integration of equipment; furthermore, after long-term operation, the wear of intermediate transmission components will lead to increased coaxiality deviation, causing bearing noise, overheating and other faults. The average maintenance cycle is only 6-8 months, and maintenance requires disassembling multiple related structures, which is complex and costly.

[0004] Therefore, there is an urgent need for a motor bearing structure that can achieve deep integration of magnetic field drive and rolling support, and also has efficient transmission and stable positioning. Utility Model Content

[0005] The purpose of this application is to provide an integrated motor bearing structure that combines magnetic field drive and rolling support, solving the problems of low transmission efficiency, poor speed adaptability, large space occupation and high maintenance cost of traditional split bearings. Through the integrated design of magnetic field drive and graded rolling support, stable operation under different speed conditions can be achieved, thereby improving the overall performance of precision equipment.

[0006] This application provides an integrated motor bearing structure that combines magnetic field drive and rolling support, including: a housing and a rotating shaft;

[0007] The rotating shaft is rotatably disposed within the housing;

[0008] The outer circumference of the middle part of the rotating shaft is provided with an annular groove;

[0009] The upper and lower walls of the groove are fixedly provided with permanent magnet arrays as magnetic field response parts, and the permanent magnet arrays are composed of S-pole and N-pole magnets arranged alternately along the circumferential direction.

[0010] A flange fixing end that extends into the groove is fixedly sleeved on the housing;

[0011] The flange fixing end is provided with a coil assembly as a magnetic field generating part, and the coil assembly is arranged opposite to the permanent magnet array with a gap between them;

[0012] A rolling friction structure is provided at the gap between the groove and the flange fixing end. The rolling friction structure includes a first rolling friction structure at the groove and a second rolling friction structure at the central shaft of the rotating shaft.

[0013] It should be noted that the term "integrated" in this article refers to integrating the magnetic field drive function and the rolling support function into the same structural unit, without relying on external independent drive or support components; the permanent magnet array of the magnetic field response unit uses neodymium iron boron material with high magnetic energy product, and its core function is to drive the rotating shaft to rotate synchronously under the action of the rotating magnetic field generated by the magnetic field generator, so as to realize direct power transmission; the flange fixing end not only provides a mounting carrier for the coil assembly, but also serves as a structural connection interface, which can be directly connected to the fixed parts of equipment such as five-axis rotary tables, simplifying the assembly process.

[0014] In existing designs, the drive and support are separate structures that require power transmission through intermediate components, and axial and radial limiting relies solely on a single mechanical bearing, resulting in low transmission efficiency and large axial runout. This application addresses this by creating an annular groove in the middle of the shaft, integrating the magnetic field response unit and the magnetic field generator within the groove. This allows the drive function to act directly on the shaft body, eliminating the intermediate transmission link and improving transmission efficiency. Simultaneously, a small gap of 0.1-0.3mm is reserved between the coil assembly and the permanent magnet array, ensuring effective magnetic field coupling while avoiding direct contact and friction, thus reducing heat generation and wear.

[0015] By constructing an integrated architecture of "magnetic field drive and rolling support," coordinated control of power transmission and axial and radial limiting is achieved. The housing provides rigid support for the overall structure, and the rotating shaft forms a magnetic field area through a groove structure. The magnetic coupling between the permanent magnet array and the coil assembly directly drives the rotating shaft to rotate, replacing the traditional transmission path of "motor, coupling, and rotating shaft," eliminating errors and losses in intermediate links. By adding a rolling friction structure, the axial and radial limiting capabilities are further enhanced, solving the problem that relying solely on magnetic field positioning is easily affected by load, fundamentally improving the stability and accuracy of the structure's operation.

[0016] In one embodiment, the permanent magnet arrays of the upper and lower walls are arranged symmetrically with respect to the central plane of the groove.

[0017] By symmetrically arranging the permanent magnet array, the axial magnetic pull on the rotating shaft during rotation can be mutually canceled out. The upward magnetic pull on the upper permanent magnet array is equal in magnitude and opposite in direction to the downward magnetic pull on the lower array, avoiding axial displacement of the rotating shaft due to uneven magnetic field distribution, thereby reducing axial wear of the bearing and extending its service life. At the same time, the symmetrical structure makes the magnetic field lines more uniformly distributed, reducing the magnetic leakage rate to below 5%, improving the magnetic field drive efficiency, and also reducing electromagnetic interference of the magnetic field to other electronic components of the equipment (such as the grating rulers, encoders, and other precision detection elements of the five-axis rotary table).

[0018] In one embodiment, the coil assembly includes a plurality of circumferentially evenly arranged split coil units sleeved on the flange fixed end body.

[0019] By disassembling the coil assembly into multiple separate coil units, maintenance flexibility and magnetic field controllability are achieved: when a single coil unit fails, only the faulty unit needs to be replaced, eliminating the need to disassemble the entire coil assembly, thus shortening maintenance time; the coil units are evenly arranged circumferentially along the flange fixing end (usually in multiples of 3, such as 6 or 9), and by independently controlling the energizing current of each coil unit, the intensity and speed of the rotating magnetic field can be flexibly adjusted to adapt to different load requirements (such as low torque during low-speed precision machining on a five-axis rotary table, and high torque during high-speed idle operation). Furthermore, the separate structure facilitates installation and debugging in confined spaces such as the inner circumference of the flange fixing end, reducing assembly difficulty.

[0020] In existing designs, the separate drive and support structures require power transmission through intermediate components, and axial positioning relies solely on a single mechanical bearing, resulting in low transmission efficiency and large axial runout. By constructing an integrated architecture of "magnetic field drive and rolling support," coordinated control of power transmission and radial positioning is achieved. The housing provides rigid support for the overall structure, and the rotating shaft forms a magnetic field area through a groove structure. The magnetic coupling between the permanent magnet array and the coil assembly directly drives the rotating shaft to rotate, replacing the traditional "motor, coupling, and rotating shaft" transmission path and eliminating errors and losses in intermediate links. Subsequently, by adding a rolling friction structure, the radial positioning capability is further enhanced, solving the problem of susceptibility to load effects when relying solely on magnetic field positioning, fundamentally improving the stability and accuracy of the structure's operation.

[0021] In one embodiment, the upper and / or lower walls of the groove are further provided with a first rolling friction structure for axially limiting the flange fixing end.

[0022] While magnetic field drive can provide a certain radial positioning force, under load fluctuations or impact conditions (such as changes in cutting force during five-axis rotary table machining), magnetic field alone is insufficient to completely limit the radial displacement of the rotary axis. By adding a first rolling friction structure to the groove wall, the radial displacement of the rotary axis can be directly constrained. At the same time, rolling friction is used to replace sliding friction (the rolling friction coefficient is only 0.001-0.005, far lower than the sliding friction coefficient of 0.1-0.3), which greatly reduces energy loss and heat generation, ensuring that the radial runout of the rotary axis is controlled within 0.005mm, meeting the high precision requirements of the five-axis rotary table.

[0023] In one embodiment, the first rolling friction structure comprises a plurality of rollers, and the wall of the groove is provided with an arcuate groove for accommodating the rollers.

[0024] The rollers are made of high-hardness bearing steel (such as GCr15) and their surface is hardened to a hardness of HRC60-65, ensuring wear resistance and load-bearing capacity. The radius of curvature of the arc-shaped groove perfectly matches the radius of the roller, and its depth is 1 / 3 to 1 / 2 of the roller diameter, ensuring that the roller can roll freely while preventing it from falling out of the groove. The rollers are evenly arranged along the circumference of the groove (the spacing is usually 15°-30°), ensuring uniform distribution of radial limiting force and avoiding wear on the groove wall caused by local stress concentration.

[0025] In one embodiment, the roller is partially embedded in the arcuate groove, partially exposed in the arcuate groove, and in contact with the outer peripheral surface of the flange fixing end.

[0026] The rollers make line contact with the outer circumference of the flange fixing end, which allows them to withstand greater radial loads compared to the point contact of balls (for the same size, the radial load capacity of rollers is 2-3 times that of balls), making them suitable for high-cutting-load scenarios in five-axis rotary table machining. The height of the roller protruding from the arc groove is 1 / 2 to 2 / 3 of its diameter, ensuring reliable contact with the flange fixing end while preventing excessive protrusion that could cause damage due to excessive force on the roller. It also allows for sufficient rolling space to reduce frictional resistance.

[0027] In one embodiment, a second rolling friction structure for radial limiting is also provided at the central axis of the shaft body.

[0028] The radial stiffness of the shaft is further enhanced by a dual-limiting design consisting of a first rolling friction structure (at the groove) and a second rolling friction structure (at the central shaft). Multiple sets of cylindrical rollers are evenly arranged on the outer circumference of the second rolling friction structure. The precise fit between the outer surface of these rollers and the journal at the central shaft (with a clearance ≤ 0.002 mm) effectively suppresses radial runout during high-speed rotation, improving positioning accuracy to within ±5″. This dual-limiting design also distributes radial load, preventing damage from overload of a single structure and extending the overall service life.

[0029] In one embodiment, the first rolling friction structure and / or the second rolling friction structure are adapted to different bearing types according to the rotational speed. Rollers are used in low-speed conditions (speed ≤ 1000 rpm), while angular contact bearings are used instead of rollers in high-speed conditions (speed > 1000 rpm). The angular contact bearing structure reduces centrifugal force and friction loss during high-speed operation through point contact and contact angle design (usually 15°, 25° or 40°). The temperature rise is 15%-20% lower than that of rollers in high-speed conditions.

[0030] In one embodiment, the flange fixing end is connected to the fixing part of the five-axis rotary table.

[0031] The flange fixing end is connected to the fixed frame or base of the five-axis turntable through circumferentially evenly arranged bolt holes. The bolts are high-strength internal hex bolts to ensure connection rigidity. This design can directly replace the original "motor + bearing" separate component of the five-axis turntable without requiring major modifications to the main structure of the turntable, reducing equipment upgrade costs, and at the same time reducing the overall size of the turntable to adapt to the needs of narrow installation spaces.

[0032] In one embodiment, the magnetic field generating unit generates a rotating magnetic field after being energized, driving the magnetic field response unit and the rotating shaft to rotate synchronously.

[0033] The specific process of magnetic field drive is as follows: an external controller (such as a servo driver for a five-axis rotary table) inputs a three-phase alternating current to the coil assembly; the split coil unit in the coil assembly generates a magnetic field that rotates with time according to the change of current; the permanent magnet array on the groove wall drives the rotating shaft to rotate synchronously under the electromagnetic torque of the rotating magnetic field; by adjusting the current frequency, the rotation speed of the shaft can be steplessly adjusted to meet the dual requirements of low-speed precision motion and high-speed and high-efficiency machining of the five-axis rotary table.

[0034] In addition, this application also provides a five-axis rotary table, characterized in that it includes an integrated motor bearing structure that integrates magnetic field drive and rolling support as described in any one of the above.

[0035] This integrated bearing structure can serve as a core component of the rotating axes (such as the A-axis for rotation around the X-axis or the C-axis for rotation around the Z-axis) of a five-axis rotary table. It connects to the rotary table base via a flange, and the top of the shaft is fixed to the rotary table (e.g., via a key or flange connection). Compared to traditional split structures, the five-axis rotary table using this structure achieves: improved positioning accuracy, reduced speed fluctuations, extended maintenance cycles, and reduced intermediate transmission components, thus lowering the equipment failure rate. Attached Figure Description

[0036] Figure 1This is a cross-sectional view of an integrated motor bearing structure that combines magnetic field drive and rolling support, provided in one embodiment of this application.

[0037] Figure 2 yes Figure 1 A magnified view of a portion of the image;

[0038] Figure 3 This is a structural diagram of an integrated motor bearing that combines magnetic field drive and rolling support, provided in one embodiment of this application.

[0039] In the picture:

[0040] 1. Shell;

[0041] 2. Shaft;

[0042] 31. Magnetic field generating unit; 311. Split-type coil unit; 32. Magnetic field response unit;

[0043] 4. Flange fixed end;

[0044] 5. First rolling friction structure;

[0045] 7. Second rolling friction structure.

[0046] The following detailed description, in conjunction with the accompanying drawings, will further illustrate this utility model. Detailed Implementation

[0047] The technical solutions of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application. It should be noted that similar reference numerals and letters in the following drawings indicate similar items. Therefore, once an item is defined in one drawing, it does not need to be further defined and explained in subsequent drawings. At the same time, in the description of this application, the terms "first," "second," etc., are only used to distinguish descriptions and should not be construed as indicating or implying relative importance.

[0048] In existing technologies, the rotary axis drive and support of five-axis rotary tables are mostly designed separately. For example, the C-axis of a certain model of five-axis rotary table is powered by a servo motor (model: Panasonic A6 series). The motor output shaft is connected to the rotary shaft through a coupling, and radial limiting is achieved by two ball bearings (model: 6208). This structure has obvious defects: the assembly error of the coupling causes the radial runout of the rotary shaft to reach 0.012mm, and the positioning accuracy is only ±7.5″; the independent arrangement of the motor and bearings increases the axial length of the rotary table by 120mm, occupying a large space; after long-term operation, the wear of the coupling causes the transmission efficiency to drop to 88%, and disassembly and maintenance are required on average every 6 months, resulting in high maintenance costs.

[0049] To address the aforementioned issues, the inventors analyzed the core shortcomings of traditional structures and discovered that "long power transmission paths" and "single radial limiting" are the key factors leading to low accuracy and poor stability. Based on this, they proposed creating an annular groove in the middle of the rotating shaft, integrating the magnetic field drive component and the rolling support component within the groove. The shaft is directly driven to rotate via magnetic coupling, while a double rolling friction structure is added to strengthen radial limiting, ultimately forming an "integrated" structural design.

[0050] Therefore, the integrated motor bearing structure combining magnetic field drive and rolling support proposed in this application also includes a rolling friction structure. The housing 1 is a rigid support carrier, and the rotating shaft 2 is rotatably disposed within the housing, with an annular groove on its outer periphery in the middle. A permanent magnet array, i.e., a magnetic field response unit 32, is provided on the groove wall. A flange fixing end 4 extends into the groove, and a coil assembly, i.e., a magnetic field generating unit 31, is sleeved on the flange fixing end 4. The rolling friction structure includes a first rolling friction structure 5 at the groove and a second rolling friction structure 7 at the central axis of the rotating shaft.

[0051] Specifically, the flange fixing end 4 is fitted into the housing 1 with an interference fit, and the length extending into the groove is 0.5-1mm less than the groove depth to avoid contact with the upper and lower bottom surfaces of the groove; the split coil unit 311 of the coil assembly is fitted onto the flange fixing end 4 and arranged evenly around the circumference, with equal spacing between adjacent units, and is fixed by epoxy resin potting to prevent displacement caused by vibration; the permanent magnet array is bonded to the groove wall with high-strength epoxy adhesive, and the wall surface needs to be sandblasted (roughness Ra1.6μm) before bonding to ensure firm bonding; the rollers of the first rolling friction structure 5 are installed in the arc groove, and after installation, high-temperature grease (such as lithium-based grease) needs to be applied to reduce friction and wear.

[0052] When the equipment is running, the external controller inputs a three-phase alternating current to the coil assembly, the coil generates a rotating magnetic field, and the permanent magnet array drives the rotating shaft 2 to rotate synchronously under the action of the magnetic field; the rollers of the first rolling friction structure 5 roll in contact with the outer circumferential surface of the flange fixed end 4, limiting the axial displacement of the rotating shaft; the rollers of the second rolling friction structure 7 further assist in radial limiting, ensuring stable rotation of the rotating shaft.

[0053] Compared with existing technologies, traditional split structures require power transmission through couplings, while this solution directly drives the device through magnetic coupling, eliminating intermediate errors; traditional radial limiting relies on a single bearing, while this solution adopts a double rolling friction structure to improve stability; traditional maintenance requires overall disassembly, while the split coil unit of this solution can be replaced individually, making maintenance more convenient.

[0054] This application further proposes that the permanent magnet arrays on the upper and lower walls are symmetrically arranged with respect to the central plane of the groove. This symmetrical design ensures that the axial magnetic pull on the rotating shaft 2 cancels each other out, preventing axial offset. For example, the S and N poles of the permanent magnet array on the upper wall are arranged alternately, and the corresponding positions on the lower wall have opposite magnetic polarities, ensuring that the upward magnetic pull on the upper wall is equal in magnitude to the downward magnetic pull on the lower wall, and the resultant axial force is zero.

[0055] This application further proposes that the coil assembly includes multiple circumferentially evenly arranged separate coil units 311. Taking six coil units as an example, the units are arranged at 60° intervals along the four circumferential directions of the flange fixing end, and each unit has an independent lead-out terminal for connection to an external controller. When a coil unit fails, the controller can detect the fault signal and issue an alarm. Maintenance personnel only need to remove the potting resin of the faulty unit, replace it with a new unit, and re-pot it. The entire maintenance process takes only 2 hours, while the maintenance of a traditional integral coil assembly takes more than 8 hours. At the same time, by adjusting the current of each coil unit, the rotating magnetic field can be finely adjusted. For example, in precision machining on a five-axis rotary table, reducing the current reduces the magnetic field strength, and the speed fluctuation is controlled within ±1 rpm, meeting high precision requirements.

[0056] This application further proposes that the upper and / or lower walls of the groove are provided with a first rolling friction structure 5 (roller and arcuate groove). In one specific embodiment, the upper and lower walls of the groove are each provided with 8 arcuate grooves, arranged at 45° intervals along the circumference. The diameter of the arcuate groove is 0.01-0.02 mm larger than the diameter of the roller to ensure that the roller can roll flexibly. The roller has a diameter of 6 mm and protrudes 3 mm above the arcuate groove, making close contact with the outer circumferential surface of the flange fixing end 4. When the rotating shaft 2 is subjected to axial load, the roller can roll along the arcuate groove, while restricting the axial displacement of the rotating shaft.

[0057] This application further proposes that a second rolling friction structure 7 is provided at the central axis of the main body of the rotating shaft 2. In one embodiment, the second rolling friction structure 7 works in conjunction with the first rolling friction structure 5 to form a three-point limit at "both ends and the middle", so that the radial runout of the rotating shaft is controlled within 0.004mm and the positioning accuracy reaches ±4.5″, which meets the precision machining requirements of the five-axis rotary table.

[0058] This application further proposes that the flange fixed end 4 is connected to the fixed part of the five-axis rotary table.

[0059] This application further proposes that after the magnetic field generating unit 31 is energized, it generates a rotating magnetic field, driving the magnetic field response unit 32 and the rotating shaft 2 to rotate synchronously. Taking the C-axis of a five-axis rotary table as an example, when the rotating shaft needs to rotate at 300 rpm, the external controller inputs a three-phase alternating current with a frequency of 50 Hz to the coil assembly. The coil generates a rotating magnetic field with a speed of 3000 rpm (magnetic field speed = current frequency × 60 / number of pole pairs, which is 10 in this embodiment). Under the action of the magnetic field, the permanent magnet array drives the rotating shaft to rotate synchronously at 300 rpm. When the speed needs to be adjusted, only the current frequency needs to be changed, for example, by adjusting the frequency to 10 Hz, and the rotating shaft speed can be reduced to 60 rpm, achieving stepless speed regulation. This driving method has a rapid response, with a speed adjustment time of ≤0.5s, which is much faster than the 1.5s speed regulation of traditional motors through reduction gears, thus improving the dynamic performance of the equipment.

[0060] Although this application discloses several aspects and embodiments, other aspects and embodiments will be obvious to those skilled in the art. Various modifications and improvements can be made without departing from the concept of this application, and these all fall within the scope of protection of this application. The various aspects and embodiments disclosed in this application are for illustrative purposes only and are not intended to limit this application. The actual scope of protection of this application is determined by the claims.

Claims

1. An integrated motor bearing structure combining magnetic field drive and rolling support, comprising a housing (1) and a rotating shaft (2), characterized in that: The rotating shaft (2) is rotatably disposed within the housing (1); the outer periphery of the middle part of the rotating shaft (2) is provided with an annular groove; the upper and lower walls of the groove are fixedly provided with a permanent magnet array serving as a magnetic field response part (32), the permanent magnet array being arranged with S-pole and N-pole magnets alternately spaced along the circumference; a flange fixing end (4) extending into the groove is fixedly sleeved on the housing (1); the flange fixing end (4) is provided with a coil assembly serving as a magnetic field generating part (31), the coil assembly being disposed opposite to the permanent magnet array and having a gap; a rolling friction structure is provided at the gap between the groove and the flange fixing end (4), the rolling friction structure including a first rolling friction structure (5) at the groove and a second rolling friction structure (7) at the central axis of the rotating shaft.

2. The integrated motor bearing structure combining magnetic field drive and rolling support according to claim 1, characterized in that: The permanent magnet arrays on the upper and lower walls are symmetrically arranged with respect to the central plane of the groove.

3. The integrated motor bearing structure combining magnetic field drive and rolling support according to claim 1 or 2, characterized in that: The coil assembly includes multiple circumferentially evenly arranged split coil units (311) sleeved on the flange fixed end (4) body.

4. The integrated motor bearing structure combining magnetic field drive and rolling support according to claim 1, characterized in that: The upper and / or lower walls of the groove are further provided with a first rolling friction structure (5) for axially limiting the flange fixing end (4).

5. The integrated motor bearing structure combining magnetic field drive and rolling support according to claim 4, characterized in that: The first rolling friction structure (5) consists of multiple rollers, and the wall of the groove is provided with an arc-shaped groove for accommodating the rollers.

6. The integrated motor bearing structure combining magnetic field drive and rolling support according to claim 5, characterized in that: The roller is partially embedded in the arc-shaped groove, and partially exposed in the arc-shaped groove and in contact with the outer peripheral surface of the flange fixing end (4).

7. The integrated motor bearing structure combining magnetic field drive and rolling support according to claim 1, characterized in that: The rotating shaft (2) is also provided with a second rolling friction structure (7) for radial limiting at the central axis of the body.

8. The integrated motor bearing structure combining magnetic field drive and rolling support according to claim 1, characterized in that: The flange fixing end (4) is connected to the fixing part of the five-axis turntable.

9. The integrated motor bearing structure combining magnetic field drive and rolling support according to claim 1, characterized in that: When the magnetic field generating unit (31) is powered on, it generates a rotating magnetic field, which drives the magnetic field response unit (32) and the rotating shaft (2) to rotate synchronously.

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