Vertical hybrid magnetic suspension bearing with gravity compensation

Abstract

The invention belongs to the technical field of magnetic suspension bearings, and particularly relates to a vertical hybrid magnetic suspension bearing with gravity compensation, which comprises a frame main body, a rotor and at least one bearing assembly fixed on the frame main body, the two ends of the bearing assembly are respectively provided with an upper end cover and a lower end cover, the upper end cover and the lower end cover are located at the two ends of the bearing assembly respectively to fix the bearing assembly, and the rotor penetrates through the bearing assembly and is suspended in the bearing assembly; the upper end cover and / or the bearing assembly are / is provided with a first magnetic part, the rotor is provided with a second magnetic part corresponding to the first magnetic part, and the first magnetic part and the second magnetic part are matched to generate vertically upward attraction force so as to carry out gravity compensation on the rotor. In order to solve the problem that a high-precision vertical magnetic suspension bearing is difficult to assemble, a reliable magnetic force compensation scheme is provided through the synergistic effect of a magnetic part and a split type axial magnetic element.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of magnetic suspension bearings, and particularly relates to a vertical hybrid magnetic suspension bearing with gravity compensation. BACKGROUND

[0002] Magnetic suspension bearings use magnetic field force to make the rotor stably suspended, have the remarkable advantages of no mechanical contact, no friction, no lubrication, high rotation speed, long service life and the like, and have been widely applied to the fields of high-speed centrifuges, flywheel energy storage, turbine machinery and the like.

[0003] In the application of vertical machine tool spindles, the gravity direction of the rotor system (including the spindle, the motor rotor and the cutting tool) is parallel to the spindle axis, and all the gravity is borne by the axial magnetic bearing. In addition, in the cutting process, the axial magnetic bearing also needs to bear the huge reaction force from the workpiece. This makes the axial magnetic bearing the component with the largest load and the most severe working conditions in the entire suspension system.

[0004] At present, the traditional solution mainly adopts a pure electromagnetic active magnetic bearing. This solution completely relies on the axial control coil to pass through the current to generate the required electromagnetic attraction force to balance the rotor gravity and overcome the machining disturbance. However, this way has many inherent defects: Firstly, in order to generate a strong magnetic field sufficient to support the entire rotor weight, the axial coil needs to continuously apply a very large bias current, which not only causes the energy consumption of the coil to increase sharply, the operation cost is high, but also causes the coil to heat seriously. The heating problem must be solved by a complex cooling system, which increases the complexity and volume of the system. Secondly, the large steady-state current also requires the power amplifier to have a large capacity, which increases the manufacturing cost and heat management difficulty of the system. Thirdly, the temperature rise caused by heating will cause the performance change of the iron core and coil material, which may affect the precision and stability of the control system, which is particularly unfavorable for ultra-precision machining. Finally, in order to generate a strong magnetic field, more coil turns and larger iron core cross section are often required, which objectively limits the miniaturization and lightweight design of the axial magnetic bearing structure, which is contrary to the demand of compact integration of the machine tool spindle.

[0005] In summary, the pure electromagnetic axial bearing used in the vertical machine tool magnetic suspension spindle in the prior art has the problems of high energy consumption, large heating, high requirements for the capacity of the power amplifier and restriction on the compactness of the structure, which has become a technical bottleneck restricting its further popularization and application.

[0006] Therefore, a new type of magnetic suspension bearing solution is urgently needed, which can effectively compensate for the main static load of the rotor gravity, fundamentally reduce the burden of the electromagnetic coil, and thus realize the miniaturization of the magnetic suspension bearing and optimize the performance of the magnetic suspension bearing. SUMMARY

[0007] The vertical hybrid magnetic suspension bearing with gravity compensation has the advantages of reducing the burden of electromagnetic coils and improving the performance of the magnetic suspension bearing.

[0008] In order to solve the above-mentioned technical problems, the present application specifically adopts the following technical solutions: The vertical hybrid magnetic suspension bearing with gravity compensation has the advantages of reducing the burden of electromagnetic coils and improving the performance of the magnetic suspension bearing. The upper end cover and / or the bearing assembly are provided with a first magnetic element, and the rotor is provided with a second magnetic element corresponding to the first magnetic element, and the first magnetic element and the second magnetic element cooperate to generate an upward vertical attractive force to compensate for the gravity of the rotor. The bearing assembly comprises a three-degree-of-freedom bearing, which comprises a radial core, an axial magnetic disk arranged in sequence, and a split axial magnetic element arranged between the radial core and the axial magnetic disk, the inner wall of the axial magnetic disk is circumferentially provided with an axial coil, the split axial magnetic element comprises at least four magnetic units, the inner wall of the radial core is provided with four radial coils corresponding to the four magnetic units, and the magnetic units and the radial coils one-to-one correspond to form at least four magnetic field control paths.

[0009] As an improvement, a pose monitoring module is further arranged between the radial core and the axial magnetic disk, the pose monitoring module comprises a bracket and at least four position sensors arranged on the bracket, the bracket and the axial magnetic element at least partially coincide in the axial direction of the bearing assembly, and the four position sensors are staggered with the four magnetic units.

[0010] As an improvement, the inner wall of the bracket protrudes radially outward to form at least four accommodating grooves, an installation part is formed between adjacent two accommodating grooves, the position sensor is arranged on the installation part, and the magnetic unit is located in the accommodating groove.

[0011] As an improvement, the installation part is recessed radially inward to form an open installation area outside the bracket, the installation part is provided with a mounting hole, the probe of the position sensor passes through the mounting hole and is located inside the bracket, and at least part of the position sensor is located in the installation area.

[0012] As an improvement, the width of the installation area gradually decreases from outside to inside, so that the installation part is in the shape of "V".

[0013] As an improvement, the radial core and / or the side opposite to the axial magnetic disc is provided with at least four limiting parts, and the four magnetic units are respectively limited in the limiting parts.

[0014] As an improvement, the axial magnetic disc comprises a first magnetic disc and a second magnetic disc arranged in an overlapping manner, and the first magnetic disc and the second magnetic disc cooperatively form a coil slot for accommodating the axial coil.

[0015] As an improvement, the thickness of the two side walls of the coil slot is the same, the magnetic unit is S-pole on the side close to the axial magnetic disc and N-pole on the side close to the radial core, so that the bias magnetic flux generated by the magnetic unit starts from the N-pole, passes through the radial core, and is uniformly distributed to the first magnetic disc and the second magnetic disc, and finally converges to the S-pole to form a closed and uniform second magnetic circuit.

[0016] As an improvement, the bearing assembly further comprises a two-degree-of-freedom bearing and at least one protective bearing.

[0017] As an improvement, one part of the side wall of the rotor extends radially outward to form an annular protruding part, and the second magnetic part is arranged on the annular protruding part.

[0018] The principles and beneficial technical effects of the present application are as follows: For high-precision vertical magnetic levitation bearings, especially for the problem of assembly difficulty caused by the gravity of the rotor during assembly, a gravity compensation scheme of multi-magnetic field ordered interaction is provided, that is, through the synergistic effect of the magnetic part and the bearing assembly designed with a split sandwich structure, a reliable magnetic force compensation scheme is provided.

[0019] Specifically, by arranging corresponding magnetic parts (i.e., magnetic field arrays) on the end cover and the rotor, the first magnetic part and the second magnetic part cooperate to generate an upward suction force to compensate for the gravity of the rotor. At the same time, a plurality of magnetic units respectively form independent magnetic circuits with the radial coil, which can to some extent avoid the invalid magnetic field generated in the non-action area of the traditional integrated axial magnetic element (in order to ensure the convenience of installation, the existing one adopts an inherent integrated permanent magnet, and the part of the permanent magnet that does not overlap with the radial coil is the "non-action area", which is most likely to generate unnecessary invalid magnetic field of the magnetic circuit), improve the uniformity of the magnetic field, and further reduce the adverse effects of non-uniform magnetic field on the magnetic field array, and ensure the compensation effect of the magnetic field array.

[0020] Further, the application also provides a magnetic circuit uniformity regulation scheme, which optimizes the magnetic field from the structure and magnetic pole distribution, and further reduces the possibility of magnetic field array being disturbed by the magnetic field, in particular, the application divides the magnetic circuit into two paths by the directional magnetic pole distribution of the magnetic unit, the first magnetic disk and the second magnetic disk with the same thickness, so that the magnetic force in the magnetic circuit is always uniform, thereby reducing the interference of the non-uniform magnetic field on the magnetic field array.

[0021] Further, the application adopts the staggered sandwich design of the split axial magnetic element and the pose monitoring module, that is, the pose monitoring module is clamped between the radial core and the axial magnetic disk, and the plurality of magnetic units are clamped in each part of the bracket, which can efficiently utilize the space and facilitate the miniaturization of the bearing. BRIEF DESCRIPTION OF DRAWINGS

[0022] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the following will briefly introduce the drawings needed to be used in the embodiments or the prior art description. In all the drawings, similar elements or parts are generally identified by similar reference numerals. In the drawings, each element or part is not necessarily drawn according to the actual proportion. Obviously, the drawings described below are some embodiments of the present application, and for those skilled in the art, other drawings can also be obtained from these drawings without creative labor.

[0023] Figure 1 is a perspective view of a three-degree-of-freedom bearing in an embodiment of the present application; Figure 2 is a front view of a three-degree-of-freedom bearing in an embodiment of the present application; Figure 3 is a partial structure schematic view of a three-degree-of-freedom bearing in an embodiment of the present application; Figure 4 is an exploded view of a front view of a three-degree-of-freedom bearing in an embodiment of the present application; Figure 5 is a magnetic circuit distribution schematic view of a hybrid magnetic levitation bearing in an embodiment of the present application; Figure 6 is an exploded structure view of a vertical hybrid magnetic levitation bearing with gravity compensation in an embodiment of the present application; Figure 7 is a sectional view of a vertical hybrid magnetic levitation bearing with gravity compensation in an embodiment of the present application.

[0024] Marked in the figure: 100, radial core; 200, axial magnetic disc; 210, first magnetic disc; 211, first shell; 212, second shell; 220, second magnetic disc; 300, magnetic unit; 400, radial coil; 500, pose monitoring module; 510, support; 511, containing groove; 512, mounting part; 513, mounting area; 520, position sensor; 521, probe; 522, adjusting piece; 600, coil groove; 700, limiting part; 800, axial coil; 30, first magnetic circuit; 31, second magnetic circuit; 32, third magnetic circuit; 33, fourth magnetic circuit; 34, fifth magnetic circuit; 35, sixth magnetic circuit; 1, upper end cover; 2, bearing cover; 3, protection bearing; 4, three-degree-of-freedom bearing; 5, two-degree-of-freedom bearing; 6, angular contact bearing; 7, lower end cover; 8, rotor; 9, frame body; 10, first magnetic piece; 11, second magnetic piece; 12, protruding part. DETAILED DESCRIPTION

[0025] In order to make the objects, technical solutions and advantages of the embodiments of the present application clearer, the following will clearly and completely describe the technical solutions in the embodiments of the present application with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are some but not all of the embodiments of the present application. Based on the embodiments in the present application, all other embodiments obtained by a person of ordinary skill in the art without creative work fall within the protection scope of the present application.

[0026] Herein, using suffixes such as "module", "part" or "unit" for representing elements is only for facilitating the description of the present application, and has no specific meaning by itself. Therefore, "module", "part" or "unit" can be mixedly used. Herein, the terms "upper", "lower", "inner", "outer", "front", "back", "one end", "the other end" and the like indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, and are only for facilitating the description of the present application and simplifying the description, and therefore cannot be understood as indicating or implying that the indicated device or element must have a specific orientation, be constructed and operated in a specific orientation, and thus cannot be understood as a limitation on the present application. In addition, the terms "first", "second" are only for the purpose of description, and cannot be understood as indicating or implying relative importance.

[0027] Herein, unless otherwise explicitly specified and limited, the terms "mount", "provided with", "connected" and the like should be understood in a broad sense, for example, "connected" can be fixed connection, can be detachable connection, or integrally connected; can be mechanical connection, can be directly connected, can be indirectly connected through intermediate medium, can be the communication inside two elements. For a person of ordinary skill in the art, the specific meaning of the above terms in the present application can be understood according to the specific circumstances. "Multiple" herein means two or more, that is, it includes two, three, four, five and the like.

[0028] Embodiment one Referring to Figures 1-5 The application provides an in-situ measured hybrid magnetic suspension bearing, comprising at least one bearing assembly, the bearing assembly comprising a radial core 100, an axial magnetic disk 200 arranged in sequence, and a split axial magnetic element arranged between the radial core 100 and the axial magnetic disk 200, the inner wall of the axial magnetic disk being circumferentially provided with an axial coil 800, the split axial magnetic element comprising at least four magnetic units 300, the inner wall of the radial core 100 being provided with at least four radial coils 400 corresponding to the magnetic units respectively, and the magnetic units 300 and the radial coils 400 one-to-one corresponding to form at least four independent magnetic field control paths.

[0029] The radial core 100 and the axial magnetic disk 200 are further provided with a pose monitoring module 500, the pose monitoring module 500 comprising a bracket 510 and at least four position sensors 520 arranged on the bracket 510, the bracket 510 and the axial magnetic element at least partially coinciding in the axial direction of the bearing assembly, and the four position sensors 520 being staggered with the four magnetic units 300.

[0030] In some embodiments, the probe of the position sensor 520 is directed towards the center of the bracket 510.

[0031] Compared with the prior art (such as Chinese invention patent CN107222132A) in which the sensor is externally arranged on the side wall of the bearing assembly, the application provides a split sandwich structure design, so that the bearing can be miniaturized while measuring the pose of the rotor in an in-situ measurement manner, thereby improving the measurement accuracy.

[0032] Specifically, in order to avoid the magnetic field inside the bearing assembly from interfering with the sensor, the conventional method is to perform pose measurement outside the bearing assembly at the expense of a certain accuracy, which is quite different from the application. The application provides a multi-magnetic field ordered interaction scheme with an internal sensor through a split sandwich structure design, so that the in-situ measurement is realized, and the magnetic field interference on the sensor can be effectively controlled, thereby realizing higher accuracy of pose measurement.

[0033] In some embodiments, the magnetic units can be permanent magnets, and four of the magnetic units are evenly arranged between the radial core and the axial disc, forming four independent magnetic circuits (permanent magnet bias magnetic circuits) in four directions; two of the four radial coils form two independent magnetic circuits (electromagnetic control magnetic circuits) for real-time adjustment and control of the magnetic field force, and the radial coils form a certain control path when controlling the magnetic field force of the magnetic units, that is, the above-mentioned at least four independent magnetic field control paths. It should be noted that the four radial coils form two control units by being connected in series or in parallel, and provide magnetic force in two directions (such as a and b directions), but each electrical path (each radial coil) can be regarded as an independent control path.

[0034] In some embodiments, the inner wall of the bracket 510 protrudes radially outward to form at least four accommodation grooves 511, and an installation portion 512 is formed between two adjacent accommodation grooves 511, the position sensor 520 is arranged on the installation portion 512, and the magnetic unit 300 is located in the accommodation groove 511. Wherein, “outward” refers to extending along the radius direction from the center of the bracket. That is, “outer” and “inner” in this article refer to the region where the outer diameter of the bracket is located and the region where the center is located, respectively. By staggered arrangement, the position sensor 520 and the magnetic unit 300 are independent of each other, and the bracket 510 can also limit the position of the magnetic unit 300.

[0035] In some embodiments, the installation portion 512 is recessed radially inward to form an open installation area 513 outside the bracket 510 (see Figure 3 ), the installation portion 512 is provided with a mounting hole, the probe of the position sensor 520 passes through the mounting hole and is located inside the bracket 510, and at least a part of the position sensor 520 is located in the installation area 513. That is, the installation area 513 is also staggered with the accommodation groove 511, and the bracket 510 divides the space between the radial core 100 and the axial disc 200 into different functional areas, such as a limiting area for installing the magnetic unit and limiting the position of the magnetic unit, an open installation area for facilitating the installation of the position sensor, and a fixing area for fixing the probe of the position sensor. It can greatly improve the space utilization while improving the independence of each component and the uniformity of the magnetic field distribution, which is beneficial to the miniaturization design of the bearing assembly. Wherein, the position of the position sensor 520 can be adjusted by the adjusting member 522.

[0036] In some embodiments, the width of the mounting area 513 gradually decreases from outside to inside, so that the mounting portion 512 is in a "V" shape. When mounting the position sensor 520 on the bracket, the position sensor 520 is aligned with the mounting hole through the open mounting area 513, and then assembled, which is convenient and fast.

[0037] In some embodiments, at least four limiting portions 700 are arranged on the radial core 100 and / or the axial disk 200, and the four magnetic units 300 are respectively limited in the limiting portions 700. That is, at least four limiting portions 700 are arranged on the side opposite to the radial core 100 and the axial disk 200, for example, the side close to the axial disk 200 of the radial core 100, or the side close to the radial core 100 of the axial disk 200. Preferably, the limiting portion 700 is arranged on the radial core 100 and corresponds to the radial core 100. By limiting the magnetic unit 300 through the limiting portion 700, the split magnetic unit 300 can be quickly aligned, the installation complexity is reduced, and the corresponding accuracy of the magnetic unit 300 and the radial coil 400 is improved.

[0038] In some embodiments, the four radial coils 400 are divided into two magnetic force groups, each magnetic force group includes two radial coils 400, and the two magnetic force groups respectively generate magnetic forces pointing to a first direction a and a second direction b, the angle between the first direction and the horizontal plane is 1°-90°, and the angle between the second direction and the horizontal plane is 90°-180°.

[0039] In some embodiments, the angle between the first direction and the horizontal plane is 45°, and the angle between the second direction and the horizontal plane is 135°. For a horizontal magnetic suspension bearing, the application also provides a gravity compensation scheme. By dividing the magnetic force group, the magnetic force group generates upward magnetic force, which can compensate the weight of the rotor.

[0040] In some embodiments, the axial disk includes a first disk 210 and a second disk 220 arranged in an overlapping manner, and the first disk 210 and the second disk 220 cooperate to form a coil slot 600 for accommodating the axial coil 800.

[0041] In some embodiments, the thickness of the two side slot walls of the coil slot 600 is the same, the magnetic unit is S-pole close to the axial disk and N-pole close to the radial core, so that the bias magnetic flux generated by the magnetic unit starts from the N-pole, passes through the radial core, and is uniformly distributed to the first disk and the second disk, and finally converges to the S-pole to form a closed and uniform second magnetic circuit 31 (see FIG. 6). Figure 5 , Figure 5Exemplarily show a magnetic circuit distribution of a five-degree-of-freedom magnetic bearing system containing the three-degree-of-freedom bearing assembly (left side) of the application).

[0042] In some embodiments, the first magnetic disk 210 includes a first shell 211 extending along the axial direction of the bearing and a second shell 212 extending along the radial direction of the bearing, the second magnetic disk 220 is parallel to the second shell 212, and the coil slot 600 is formed by the side wall of the first shell 211 abutting the second shell 212 to form an internal opening, the axial coil 800 is installed to the coil slot 600 through the opening, and the opening faces the rotor.

[0043] Based on the above bearing assembly, the present application exemplarily provides a five-degree-of-freedom magnetic bearing system circuit distribution diagram, referring to Figure 5 , the left side is the above-mentioned bearing assembly (three-degree-of-freedom bearing assembly), and the right side is a two-degree-of-freedom bearing assembly. First, the bias magnetic flux generated by the magnetic element of the three-degree-of-freedom bearing assembly starts from the N level, passes through the radial core, enters the air gap between the bearing assembly and the rotor 8, and then flows to the first magnetic disk and the second magnetic disk through the rotor 8, and then converges at the S level of the magnetic element to form a complete second magnetic circuit 31 to simultaneously provide the bias magnetic flux of the axial magnetic force in two directions and the bias magnetic flux of the radial magnetic force. Similarly, the bias magnetic flux generated by the two-degree-of-freedom bearing starts from the N level of the magnetic element, passes through the radial core, enters the air gap, and then flows to the axial magnetic disk on the other side through the rotor 8, and converges at the S level of the magnetic element to form a complete fifth magnetic circuit 34 to provide the bias magnetic flux of the radial magnetic force.

[0044] When the radial coils inside the three-degree-of-freedom and two-degree-of-freedom are passed through the current, the magnetic flux generated by the coils forms different degree-of-freedom closed-loop magnetic circuits (including the third magnetic circuit 32, the fourth magnetic circuit 33, and the sixth magnetic circuit 35) through the axial magnetic disk and the rotor 8, and adjusts the size and direction of the radial magnetic suspension force in cooperation with the second magnetic circuit 31 and the fifth magnetic circuit 34.

[0045] When the axial coil of the three-degree-of-freedom is passed through the current, the magnetic flux generated by the coil forms the first magnetic circuit 30 through the first magnetic disk, the shaft shoulder of the rotor 8, and the second magnetic disk, and adjusts the size and direction of the axial magnetic suspension force in cooperation with the second magnetic circuit 31 which can provide the axial magnetic force in two directions.

[0046] By cooperating the directional magnetic poles of the split axial magnetic disk and the magnetic element, a magnetic circuit uniformity regulation scheme is provided. Specifically, the application optimizes the magnetic field from the structure and the magnetic pole distribution. When the magnetic flux generated by the magnetic element flows from the N level to the axial magnetic disk, it is uniformly distributed to the split first magnetic disk and the second magnetic disk with the same thickness, which can further improve the uniformity of the magnetic field inside the bearing, thereby reducing the interference of the non-uniform magnetic field on the sensor.

[0047] To sum up, the application provides a multi-magnetic-field ordered interaction scheme with a built-in sensor through a split sandwich structure design, which can effectively control the magnetic field interference on the sensor while realizing in-situ measurement, thereby realizing higher-precision pose measurement.

[0048] Specifically, first, the application sets a split axial magnetic element and a pose monitoring module, which are designed in a staggered sandwich. That is, the pose monitoring module is clamped between the radial core and the axial magnetic disk, and multiple magnetic units are clamped in each part of the bracket. On the one hand, the space can be used efficiently, which is conducive to the miniaturization of the bearing. Meanwhile, the multiple magnetic units form independent magnetic field control paths with the radial coil, which can reduce the invalid magnetic field generated by the non-acting area of the traditional integrated axial magnetic element to a certain extent (in order to ensure the convenience of installation, the existing ones all adopt an integrated permanent magnet, and the non-overlapping part of the permanent magnet and the radial coil is the "non-acting area", which is most likely to generate unnecessary invalid magnetic field of the magnetic circuit), thereby reducing the magnetic interference on the sandwiched sensor and improving the detection accuracy of the sensor.

[0049] Further, the application also provides a magnetic circuit uniformity regulation scheme, which optimizes the magnetic field from the structure and magnetic pole distribution, further reduces the possibility of magnetic field interference on the position sensor arranged in a sandwich, and specifically, the application divides the magnetic circuit into two paths by the directional magnetic pole distribution of the magnetic unit combined with the first magnetic disk and the second magnetic disk with consistent thickness, so that the magnetic force in the magnetic circuit is always uniform, thereby reducing the interference of non-uniform magnetic field on the sensor and simplifying the structure of the rotor and the bearing assembly and their assembly to realize miniaturization.

[0050] Further, the modular pose monitoring module cooperates with the split axial magnetic element, which only needs to be aligned once during installation, such as first installing the axial magnetic element on the radial core, and then automatically aligning the pose monitoring module through the positioning action of the axial magnetic element, thereby improving the convenience of bearing assembly.

[0051] Further, for horizontal magnetic levitation bearings, the application also provides a gravity compensation scheme, which divides the magnetic force group to generate upward magnetic force on the bearing, which can reduce the possibility of deviation of the entire bearing, especially during installation.

[0052] Embodiment two The embodiment provides an assembly method of a hybrid magnetic levitation bearing for in-situ measurement, based on the hybrid magnetic levitation bearing for in-situ measurement in embodiment one, which comprises the following steps: S100, install the position sensor on the bracket, and adjust the probe of the sensor to zero to form a pose monitoring module; S200, fixing the split axial magnetic element on the radial core; wherein the plurality of magnetic units can be positioned by the limiting portion on the side wall of the radial core, so as to facilitate quick installation of the split axial magnetic element; S300, installing the pose monitoring module on the radial core on which the axial magnetic element is fixed; S400, combining the radial core and the axial magnetic disk to form the bearing assembly as a whole.

[0053] In combination with the above assembly method, the application actually provides a modular installation scheme, that is, even if the split sandwich structure design, the assembly can be quickly performed. Specifically, first, the split magnetic units are quickly assembled through the limiting portion, then the pose monitoring module is quickly installed as a whole to the radial core, and then the radial core and the axial magnetic disk are combined to complete the assembly, which is convenient and fast.

[0054] Embodiment three Referring to Figures 1-7 , the embodiment provides a vertical hybrid magnetic levitation bearing with gravity compensation, which comprises a frame body 9, a rotor 8, and a bearing assembly fixed on the frame body 9. The bearing assembly is provided with an upper end cover 1 and a lower end cover 7 at two ends thereof. The upper end cover 1 and the lower end cover 7 are respectively located at two ends of the bearing assembly and fix the bearing assembly in the frame body 9. The rotor 8 passes through the bearing assembly and is suspended in the bearing assembly. The upper end cover 1 and / or the bearing assembly are provided with a first magnetic part 10. The rotor 8 is provided with a second magnetic part 11 corresponding to the first magnetic part 10. The first magnetic part 10 and the second magnetic part 11 cooperate to generate an upward vertical (i.e. axial) attractive force to compensate the gravity of the rotor.

[0055] The bearing assembly comprises a three-degree-of-freedom bearing 4, which comprises a radial core 100, an axial magnetic disk 200 arranged in sequence, and a split axial magnetic element arranged between the radial core 100 and the axial magnetic disk 200. The inner wall of the axial magnetic disk 200 is circumferentially provided with an axial coil 800. The split axial magnetic element comprises at least four magnetic units 300. The inner wall of the radial core 100 is provided with four radial coils 400 corresponding to the four magnetic units 300 respectively. The magnetic units 300 and the radial coils 400 one-to-one correspond to form at least four independent magnetic field control paths.

[0056] In some embodiments, a pose monitoring module 500 is further arranged between the radial core 100 and the axial magnetic disk 200, the pose monitoring module 500 comprising a bracket 510 and at least four position sensors 520 arranged on the bracket 510, the bracket 510 and the axial magnetic element at least partially coincide in the axial direction of the bearing assembly, and the four position sensors 520 are staggered with the four magnetic units 300.

[0057] In some embodiments, the inner wall of the bracket 510 is convex radially outward to form at least four accommodation grooves 511, and an installation portion 512 is formed between two adjacent accommodation grooves 511, the position sensor 520 is arranged on the installation portion 512, and the magnetic unit 300 is located in the accommodation groove 511.

[0058] In some embodiments, the installation portion 512 is concave radially inward to form an open installation area 513 outside the bracket 510, the installation portion 512 is provided with a mounting hole, the probe of the position sensor 520 passes through the mounting hole and is located inside the bracket 510, and at least part of the position sensor 520 is located in the installation area 513.

[0059] In some embodiments, the width of the installation area 513 gradually decreases from outside to inside, so that the installation portion is in the shape of a "V".

[0060] In some embodiments, the opposite side of the radial core 100 and / or the axial magnetic disk 200 is provided with at least four limiting portions 700, and the four magnetic units 300 are respectively limited in the limiting portions 700.

[0061] In some embodiments, the axial magnetic disk comprises a first magnetic disk 210 and a second magnetic disk 220 arranged in an overlapping manner, and the first magnetic disk 210 and the second magnetic disk 220 cooperate to form a coil groove 600 for accommodating the axial coil 800.

[0062] In some embodiments, the two side groove walls of the coil groove 600 have the same thickness, the magnetic unit has an S pole close to the axial magnetic disk and an N pole close to the radial core, so that the bias magnetic flux generated by the magnetic unit starts from the N pole, passes through the radial core, and is evenly distributed to the first magnetic disk and the second magnetic disk, and finally converges to the S pole to form a closed and uniform second magnetic circuit 31 (see Figure 5 ).

[0063] In some embodiments, the bearing assembly further comprises a two-degree-of-freedom bearing 5, at least one protective bearing 3, and at least one angular contact bearing 6.

[0064] In some embodiments, the three-degree-of-freedom bearing 4 is further provided with a bearing cover 2 between the upper end cover 1, and in the present embodiment, the first magnetic member 10 can be arranged on the bearing cover 2, that is, on the bearing assembly.

[0065] In some embodiments, one part of the side wall of the rotor 8 extends radially outward to form a ring-shaped protrusion 12, and the second magnetic member 11 is arranged on the ring-shaped protrusion 12.

[0066] In some embodiments, the first magnetic member 10 and the second magnetic member 11 are Halbach magnetic field arrays.

[0067] In some embodiments, the three-degree-of-freedom bearing can adopt the structure of the bearing assembly in Embodiment I.

[0068] For high-precision vertical magnetic levitation bearings, especially for the problem of assembly difficulty caused by the gravity of the rotor during assembly, the present application provides a multi-magnetic-field ordered interaction scheme based on a split bearing assembly. Through the cooperation of the magnetic member and the bearing assembly designed with a split sandwich structure, the magnetic field inside the bearing assembly and the magnetic field outside the bearing assembly (mainly the magnetic field between the first magnetic member and the second magnetic member) can be ordered and stably independently operated while the gravity is compensated by magnetic force, thereby providing a reliable magnetic force gravity compensation scheme.

[0069] Specifically, first, by arranging corresponding magnetic members on the end cover and the rotor, the first magnetic member and the second magnetic member cooperate to generate an upward suction force to compensate for the gravity of the rotor. At the same time, a plurality of magnetic units respectively form independent magnetic field control paths with radial coils, which can to some extent avoid the invalid magnetic field generated in the non-action area of the traditional integrated axial magnetic element (in order to ensure the convenience of installation, the existing ones all adopt inherent integrated permanent magnets, and the part of the permanent magnet that does not overlap with the radial coil is the "non-action area", which is most likely to generate unnecessary invalid magnetic field of the magnetic circuit), improve the uniformity of the magnetic field, and further reduce the adverse effects of non-uniform magnetic field on the magnetic field array, and ensure the compensation effect of the magnetic field array.

[0070] Further, the application also provides a magnetic circuit uniformity regulation scheme, which optimizes the magnetic field from the structure and magnetic pole distribution, further reduces the possibility of magnetic field array being disturbed by magnetic field, and specifically, the present application divides the magnetic circuit into two paths by the directional magnetic pole distribution of the magnetic unit combined with the first magnetic disk and the second magnetic disk with consistent thickness, so that the magnetic force in the magnetic circuit is always uniform, thereby further reducing the interference of non-uniform magnetic field on the magnetic field array.

[0071] Furthermore, the present application adopts an interlaced sandwich design through the split axial magnetic element and the posture monitoring module. That is, the posture monitoring module is clamped between the radial iron core and the axial magnetic disk, and multiple magnetic units are clamped in various parts of the bracket, which can make efficient use of space and facilitate the miniaturization of the bearing.

[0072] It should be noted that, in this document, the terms "comprises," "includes," or any other variations thereof are intended to encompass non-exclusive inclusion, such that a process, method, article, or apparatus comprising a series of elements includes not only those elements but also other elements not explicitly listed, or elements inherent to such process, method, article, or apparatus. In the absence of further limitations, an element defined by the phrase "comprising a ..." does not exclude the presence of other identical elements in the process, method, article, or apparatus comprising the element.

[0073] The embodiments of the present invention are described above in conjunction with the accompanying drawings, but the present invention is not limited to the above-mentioned specific implementation methods. The above-mentioned specific implementation methods are merely illustrative and not restrictive. Under the guidance of the present invention, ordinary technicians in this field can also make many forms without departing from the scope of protection of the present invention and the claims, all of which are protected by the present invention.

Claims

1. A vertical hybrid magnetic bearing with gravity compensation, characterized in that: It comprises a frame body (9), a rotor (8), and a bearing assembly fixed to the frame body (9), wherein an upper end cover (1) and a lower end cover (7) are respectively provided at both ends of the bearing assembly, the upper end cover (1) and the lower end cover (7) are respectively located at both ends of the bearing assembly to fix it, and the rotor (8) passes through the bearing assembly and is suspended in the bearing assembly; A first magnetic member (10) is provided on the upper end cover (1) and / or the bearing assembly, and a second magnetic member (11) corresponding to the first magnetic member (10) is provided on the rotor (8), wherein the first magnetic member (10) and the second magnetic member (11) cooperate to generate a vertical upward suction force to compensate for the gravity of the rotor (8); The bearing assembly includes a three-degree-of-freedom bearing (4), the three-degree-of-freedom bearing (4) including a radial iron core (100), an axial magnetic disk (200) arranged in sequence, and a split axial magnetic element arranged between the radial iron core (100) and the axial magnetic disk (200), the inner wall of the axial magnetic disk (200) being circumferentially provided with an axial coil (800), the split axial magnetic element including at least four magnetic units (300), the inner wall of the radial iron core (100) being provided with four radial coils (400) respectively corresponding to the four magnetic units (300), the magnetic units (300) and the radial coils (400) forming at least four magnetic field control paths in a one-to-one correspondence.

2. The vertical hybrid magnetic bearing with gravity compensation according to claim 1, characterized in that: A posture monitoring module (500) is further provided between the radial core (100) and the axial magnetic disk (200), the posture monitoring module (500) comprising a bracket (510) and at least four position sensors (520) provided on the bracket (510), the bracket (510) and the axial magnetic element at least partially overlap in the axial direction of the bearing assembly, and the four position sensors (520) and the four magnetic units (300) are staggered.

3. The vertical hybrid magnetic bearing with gravity compensation according to claim 2, characterized in that: The inner wall of the bracket (510) protrudes radially outward to form at least four accommodating grooves (511), a mounting portion (512) is formed between two adjacent accommodating grooves (511), the position sensor (520) is arranged on the mounting portion (512), and the magnetic unit (300) is located in the accommodating groove (511).

4. The vertical hybrid magnetic bearing with gravity compensation according to claim 3, characterized in that: The mounting portion (512) is recessed radially inward to form an open mounting area (513) located outside the bracket (510); a mounting hole is provided on the mounting portion (512); a probe (521) of the position sensor (520) passes through the mounting hole and is located inside the bracket (510); and at least a portion of the position sensor (520) is located within the mounting area (513).

5. The vertical hybrid magnetic bearing with gravity compensation according to claim 4, characterized in that: The width of the installation area (513) gradually decreases from the outside to the inside, so that the installation portion (512) is in a "V" shape.

6. The vertical hybrid magnetic bearing with gravity compensation according to claim 1, characterized in that: At least four limiting portions are provided on one side opposite to the radial iron core (100) and / or the axial magnetic disk (200), and the four magnetic units (300) are respectively limited within the limiting portions.

7. The vertical hybrid magnetic bearing with gravity compensation according to claim 1, characterized in that: The axial magnetic disk (200) comprises a first magnetic disk (210) and a second magnetic disk (220) which are arranged in an overlapping manner, wherein the first magnetic disk (210) and the second magnetic disk (220) cooperate to form a coil slot (600) for accommodating the axial coil (800).

8. The vertical hybrid magnetic bearing with gravity compensation according to claim 7, characterized in that: The thickness of the slot walls on both sides of the coil slot (600) is the same, and the side of the magnetic unit (300) close to the axial magnetic disk (200) is an S pole, and the side close to the radial iron core (100) is an N pole, so that the bias magnetic flux generated by the magnetic unit (300) starts from the N pole, passes through the radial iron core (100), and is evenly distributed to the first magnetic disk (210) and the second magnetic disk (220), and finally converges to the S pole to form a closed and uniform second magnetic circuit (31).

9. The vertical hybrid magnetic bearing with gravity compensation according to claim 1, characterized in that: The bearing assembly further comprises a two-degree-of-freedom bearing (5) and at least one protective bearing (3).

10. The vertical hybrid magnetic bearing with gravity compensation according to claim 1, characterized in that: A portion of the side wall of the rotor (8) extends radially outward to form an annular protrusion (12), and the second magnetic member (11) is arranged on the annular protrusion (12).

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