High-speed direct-drive CT radial permanent magnetic suspension bearing system
By designing a radial permanent magnet suspension bearing system with concentric clearance between the stator permanent magnet double semi-ring and the rotor permanent magnet ring, the problems of limited speed and high noise of CT machines were solved, and the high-speed and stable operation of CT machines and noise reduction were achieved.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- SHANGHAI BOHONGKE IND & TRADE CO LTD
- Filing Date
- 2026-04-08
- Publication Date
- 2026-06-02
AI Technical Summary
The rotational speed of existing CT scanners is limited, making it difficult to meet the requirements of high-speed direct drive. Furthermore, existing magnetic levitation bearing systems rely on complex electronic control systems and lack a radial permanent magnet levitation bearing technology solution that achieves stable levitation by permanent magnet force through mechanical control.
A radial permanent magnet levitation bearing system for a high-speed direct-drive CT scanner was designed. It adopts a stator permanent magnet double semi-ring and a rotor permanent magnet ring with concentric clearance, and is equipped with auxiliary mechanical control to protect the bearing. The mechanical control achieves stable levitation by permanent magnet force, avoiding the need for electronic control systems, increasing speed and reducing noise.
This has enabled the CT scanner to operate at high speed and stably, increased the equipment's rotation speed and lifespan, reduced operating noise, and shortened the CT scan radiation time.
Smart Images
Figure CN122129484A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of magnetic levitation bearing technology, and in particular to a radial permanent magnet levitation bearing system for a high-speed direct-drive CT scanner. Background Technology
[0002] Research on permanent magnet levitation bearings can be traced back to the 1840s, initially focusing on their fundamental principles. In the 1930s, Western scientists pioneered specialized research on magnetic levitation bearings, laying the theoretical foundation for subsequent technological implementation. The successful development of samarium-cobalt permanent magnet materials in 1978, followed by the commercial application of a series of high-performance rare-earth permanent magnet materials, not only provided crucial material support for the technological iteration of permanent magnet levitation bearings but also created feasibility for their application in precision medical equipment such as CT scanners.
[0003] Since 2004, a Chinese bearing company has taken the lead in developing rolling bearings for CT scanners. In 2015, domestic CT scanner rolling bearing technology was upgraded, further improving bearing precision and effectively reducing operating noise, thus promoting the development of domestic CT scanner technology. Currently, domestically manufactured CT scanners still use thin-walled rolling bearings as support components, with a maximum operating speed of 240 rpm, and technological development remains limited to mechanical rolling bearing systems.
[0004] In 2020, magnetic levitation technology began to penetrate the field of CT scanner bearings. Among them, ThyssenKrupp developed a new type of silent magnetic levitation bearing (patent number: WO2020083990A1) to solve the technical problem of high noise during CT scanning. This is the first time that magnetic levitation technology has been innovatively applied to the main bearing of a CT scanner. Through a digital electronic intelligent control system, the bearing is levitated with high precision using electromagnetic force, which can ensure the high-precision operation of the CT equipment, effectively reduce scanning noise, and shorten CT examination and radiation time. It shows great development potential in the fields of high-precision medical imaging and medical diagnosis.
[0005] The thin-walled rolling bearing support scheme currently used in domestic CT scanners suffers from speed limitations; the maximum speed of 240 rpm is insufficient to meet the high-speed direct-drive requirements of CT scanners. While ThyssenKrupp's magnetic levitation bearing solution has improved CT scanner performance, it requires a digital electronic control system to achieve stable electromagnetic levitation, resulting in a relatively complex system structure. Overall, existing technologies lack a permanent magnet levitation bearing system for CT scanners that achieves stable levitation through mechanical control and eliminates the need for an electronic control system. Furthermore, a radial permanent magnet levitation bearing technology solution that can significantly increase the operating speed of CT scanners, extend bearing life, and effectively shorten CT scan radiation time has not yet emerged, becoming a problem hindering the upgrade of CT scanners towards high-speed direct drive. Summary of the Invention
[0006] The purpose of this invention is to provide a radial permanent magnet levitation bearing system for a high-speed direct-drive CT scanner, which utilizes mechanical control to achieve stable levitation using permanent magnet force, avoiding reliance on electronic control systems, while simultaneously increasing the operating speed of the CT scanner, shortening CT examination time, and reducing noise.
[0007] To achieve the above objectives, the present invention provides a radial permanent magnet suspension bearing system for a high-speed direct-drive CT machine, comprising a stator permanent magnet double half-ring, a rotor permanent magnet ring, a first outer ring seat, left and right auxiliary mechanical control and protection bearings, a first inner ring seat, a second inner ring seat, a direct-drive CT machine motor rotor, a direct-drive CT machine motor stator, and a second outer ring seat. The stator permanent magnet double half-ring is clamped between the outer rings of the left and right auxiliary mechanical control protection bearings, and the stator permanent magnet double half-ring is embedded in the first outer ring seat and the second outer ring seat. The first outer ring seat, the stator permanent magnet double half-ring and the second outer ring seat are fixed by bolts, and together with the outer rings of the left and right auxiliary mechanical control protection bearings, they form the outer ring system of the radial permanent magnet suspension bearing. The first outer ring seat is an integral seat of the outer ring of the left auxiliary mechanical control protection bearing and the stator permanent magnet double half-ring, and the second outer ring seat is an integral seat of the outer ring of the right auxiliary mechanical control protection bearing and the stator permanent magnet double half-ring. The rotor permanent magnet ring is clamped between the inner rings of the left and right auxiliary mechanical control protection bearings, and the rotor permanent magnet ring is externally embedded in the first inner ring seat and the second inner ring seat. The first inner ring seat, the rotor permanent magnet ring and the second inner ring seat are fixed by bolts, and together with the inner rings of the left and right auxiliary mechanical control protection bearings, they form the inner ring system of the radial permanent magnet suspension bearing. The first inner ring seat is an integral seat of the inner ring of the left auxiliary mechanical control protection bearing and the rotor permanent magnet ring, and the second inner ring seat is an integral seat of the inner ring of the right auxiliary mechanical control protection bearing and the rotor permanent magnet ring. The direct-drive CT machine motor rotor is fixedly connected to the second inner ring seat by bolts, that is, the direct-drive CT machine motor rotor is fixedly connected to the inner ring system of the radial permanent magnet suspension bearing. The stator of the direct-drive CT machine motor is fixedly connected to the second outer ring seat by bolts, that is, the stator of the direct-drive CT machine motor is fixedly connected to the outer ring system of the radial permanent magnet suspension bearing.
[0008] Preferably, the stator permanent magnet double half-ring is a structure composed of an upper stator permanent magnet ring and a lower stator permanent magnet ring with opposite magnetic poles. The stator permanent magnet double half-ring is made by cutting an axially magnetized complete permanent magnet ring into two half-rings along the horizontal radial axis of symmetry, and then rotating the upper permanent magnet half-ring around the vertical axis by 180 degrees. This ensures that when the stator permanent magnet double half-ring and the axially magnetized rotor permanent magnet ring are in a clearance fit, the opposite poles of the upper half attract each other, and the like poles of the lower half repel each other. The stator permanent magnet double half-ring and the rotor permanent magnet ring are in a concentric clearance fit position.
[0009] Preferably, the stator permanent magnet double half-ring and the rotor permanent magnet ring have the same width, the rotor permanent magnet ring and the stator permanent magnet double half-ring have the same thickness and width, a gap is provided between the stator permanent magnet double half-ring and the rotor permanent magnet ring, and the center diameter of the gap between the stator permanent magnet double half-ring and the rotor permanent magnet ring is consistent with the center diameter of the ceramic ball of the left and right auxiliary mechanical control protection bearings.
[0010] Preferably, the stator permanent magnet double half-ring and the rotor permanent magnet ring are both made of permanent magnet materials, and the surface is galvanized. The galvanized layer is uniform, smooth, free of sand holes and without peeling.
[0011] Preferably, the left and right auxiliary mechanical control protection bearings are two thin-walled angular contact ceramic ball bearings, which are installed face to face. The inner rings of the two thin-walled angular contact ceramic ball bearings are respectively fitted onto the bearing shafts of the first inner ring seat and the second inner ring seat using a radial transition fit. The outer rings are respectively installed in the bearing holes of the first outer ring seat and the second outer ring seat. The axial end faces of the inner and outer rings respectively abut against the rotor permanent magnet ring and the stator permanent magnet double half ring. A preload is applied to the two thin-walled angular contact ceramic ball bearings by tightening the bolts of the inner and outer ring systems of the radial permanent magnet suspension bearings to prevent the ceramic balls of the thin-walled angular contact ceramic ball bearings from slipping, thereby playing the role of auxiliary mechanical control protection.
[0012] Preferably, the first-order bending critical speed of the rotor-bearing system of the radial permanent magnet levitation bearing system is greater than 15% to 20% of the rated operating speed of the CT scanner.
[0013] Preferably, the thin-walled angular contact ceramic ball bearing only bears preload and minor external load, serving as an auxiliary positioning, mechanical control, and protection function. The number of its ceramic balls is reduced to 1 / 3 of that of a normal bearing to reduce noise.
[0014] Therefore, this invention adopts the above-mentioned radial permanent magnet suspension bearing system for a high-speed direct-drive CT machine, and innovatively designs an inner and outer ring system similar to a rolling bearing, combined with an auxiliary mechanical control protection bearing system. The stator permanent magnet ring is specially processed and then concentrically and clearance-fitted with the rotor permanent magnet ring. Stable suspension by permanent magnet force is achieved through mechanical control, eliminating the need for an electronic control system. This ensures high-speed and stable operation of the CT machine, increases the equipment speed and service life, reduces operating noise, and shortens the CT examination radiation time.
[0015] The technical solution of the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. Attached Figure Description
[0016] Figure 1 This is a structural diagram of the radial permanent magnet levitation bearing system according to an embodiment of the present invention; Figure 2 This is a schematic diagram of the radial permanent magnet levitation principle according to an embodiment of the present invention; Figure 3 This is a load-bearing capacity curve of the radial permanent magnet levitation bearing according to an embodiment of the present invention.
[0017] Figure Labels 1. Stator permanent magnet double half ring; 2. Rotor permanent magnet ring; 3. First outer ring seat; 4. Left and right auxiliary mechanical control and protection bearings; 5. First inner ring seat; 6. Second inner ring seat; 7. Direct drive CT machine motor rotor; 8. Direct drive CT machine motor stator; 9. Second outer ring seat. Detailed Implementation
[0018] The technical solution of the present invention will be further described below with reference to the accompanying drawings and embodiments.
[0019] Unless otherwise defined, the technical or scientific terms used in this invention shall have the ordinary meaning understood by one of ordinary skill in the art to which this invention pertains. The terms "first," "second," and similar terms used in this invention do not indicate any order, quantity, or importance, but are merely used to distinguish different components. Terms such as "comprising" or "including" mean that the element or object preceding the word encompasses the elements or objects listed following the word and their equivalents, without excluding other elements or objects. Terms such as "connected" or "linked" are not limited to physical or mechanical connections, but can include electrical connections, whether direct or indirect. Terms such as "upper," "lower," "left," and "right" are used only to indicate relative positional relationships; when the absolute position of the described object changes, the relative positional relationship may also change accordingly.
[0020] Example 1 This invention provides a radial permanent magnet levitation bearing system for a high-speed direct-drive CT scanner, such as... Figure 1 , Figure 2 As shown, the components include a stator permanent magnet double half ring 1, a rotor permanent magnet ring 2, a first outer ring seat 3, left and right auxiliary mechanical control and protection bearings 4, a first inner ring seat 5, a second inner ring seat 6, a direct-drive CT machine motor rotor 7, a direct-drive CT machine motor stator 8, and a second outer ring seat 9.
[0021] The stator permanent magnet double half-ring 1 is clamped between the outer rings of the left and right auxiliary mechanical control and protection bearings 4, and the stator permanent magnet double half-ring 1 is embedded in the first outer ring seat 3 and the second outer ring seat 9. The first outer ring seat 3, the stator permanent magnet double half-ring 1 and the second outer ring seat 9 are fixed together by bolts, and together with the outer rings of the left and right auxiliary mechanical control and protection bearings 4, they form the outer ring system of the radial permanent magnet suspension bearing. The first outer ring seat 3 is an integral seat of the outer ring of the left auxiliary mechanical control and protection bearing and the stator permanent magnet double half-ring 1, and the second outer ring seat 9 is an integral seat of the outer ring of the right auxiliary mechanical control and protection bearing and the stator permanent magnet double half-ring 1.
[0022] The rotor permanent magnet ring 2 is clamped between the inner rings of the left and right auxiliary mechanical control and protection bearings 4, and is externally embedded in the first inner ring seat 5 and the second inner ring seat 6. The first inner ring seat 5, the rotor permanent magnet ring 2, and the second inner ring seat 6 are fixed together by bolts, forming the inner ring system of the radial permanent magnet suspension bearing with the inner rings of the left and right auxiliary mechanical control and protection bearings 4. The first inner ring seat 5 is an integral seat for the inner ring of the left auxiliary mechanical control and protection bearing and the rotor permanent magnet ring, and the second inner ring seat 6 is an integral seat for the inner ring of the right auxiliary mechanical control and protection bearing and the rotor permanent magnet ring 2.
[0023] The rotor 7 of the direct-drive CT machine motor is fixedly connected to the second inner ring seat 6 by bolts, that is, the rotor 7 of the direct-drive CT machine motor is fixedly connected to the inner ring system of the radial permanent magnet suspension bearing; the stator 8 of the direct-drive CT machine motor is fixedly connected to the second outer ring seat 9 by bolts, that is, the stator 8 of the direct-drive CT machine motor is fixedly connected to the outer ring system of the radial permanent magnet suspension bearing.
[0024] The stator permanent magnet double half-ring 1 is a structure composed of an upper stator permanent magnet ring and a lower stator permanent magnet ring with opposite magnetic poles. The stator permanent magnet double half-ring 1 is made by cutting an axially magnetized complete permanent magnet ring into two half-rings along the horizontal radial axis of symmetry, and then rotating the upper permanent magnet half-ring around the vertical axis by 180 degrees. When the stator permanent magnet double half-ring 1 and the axially magnetized rotor permanent magnet ring 2 are in a clearance fit, the opposite poles of the upper half attract each other and the like poles of the lower half repel each other. The stator permanent magnet double half-ring 1 and the rotor permanent magnet ring 2 are in a concentric clearance fit position.
[0025] The stator permanent magnet double half-ring 1 and the rotor permanent magnet ring 2 have the same width, which is 17.5 mm in this embodiment. The rotor permanent magnet ring 2 and the stator permanent magnet double half-ring 1 have the same thickness and width. A gap is provided between the stator permanent magnet double half-ring 1 and the rotor permanent magnet ring 2, which is 1 mm in this embodiment. The center diameter of the gap between the stator permanent magnet double half-ring 1 and the rotor permanent magnet ring 2 is consistent with the center diameter of the ceramic ball of the left and right auxiliary mechanical control protection bearings 4.
[0026] Both the stator permanent magnet double half-ring 1 and the rotor permanent magnet ring 2 are made of permanent magnet materials, specifically neodymium iron boron (N35) in this embodiment, with remanence... B r =1.18~1.24T, coercivity H cb =868~963KA / m, and the surface is galvanized, with a uniform, smooth galvanized layer, free of pinholes and peeling.
[0027] The left and right auxiliary mechanical control protection bearings 4 are two thin-walled angular contact ceramic ball bearings, which are installed face-to-face. In this embodiment, the center diameter of the ceramic balls in the two thin-walled angular contact ceramic ball bearings is 924.4 mm, and the external dimensions are Φ889×Φ959.8×25.4×35.4. The inner rings of the two thin-walled angular contact ceramic ball bearings are respectively fitted onto the bearing shafts of the first inner ring seat 5 and the second inner ring seat 6 using a radial transition fit. The outer rings are respectively installed in the seat holes of the first outer ring seat 3 and the second outer ring seat 9. The axial end faces of the inner and outer rings respectively abut against the rotor permanent magnet ring 2 and the stator permanent magnet double half ring 1. The bolts that lock the inner and outer ring systems of the radial permanent magnet suspension bearings are used to apply a preload to the two thin-walled angular contact ceramic ball bearings to prevent the ceramic balls from slipping, thus playing a role in auxiliary mechanical control protection. Thin-walled angular contact ceramic ball bearings only bear preload and small external loads, greatly improving their service life. They play a role in auxiliary positioning, mechanical control, and protection. The number of ceramic balls in their bearings can be reduced to 1 / 3 of that in normal bearings, thus reducing noise.
[0028] In this embodiment, the outer radius of the stator permanent magnet double half-ring 1 is 480.2 mm, and the inner radius is 462.7 mm. The outer radius of the rotor permanent magnet ring 2 is 461.7 mm, and the inner radius is 444.2 mm. The designed rated operating speed is 300~480 rpm. Based on these design parameters, performance verification was conducted, as follows: Theoretically, the rotor permanent magnet ring 2 can withstand an upward levitation load of 7.985 kN. In this embodiment, with the permanent magnet levitation bearing structure, at the concentric position coordinate 0, the permanent magnet levitation bearing can withstand a downward external load of 7985 N. In the radial direction... δ When the displacement is from -0.5mm to 0.5mm, the load-bearing capacity of the permanent magnet levitation bearing first gradually decreases from 8216N to 7985N, and then gradually increases from 7985N to 8276N. Specifically... Figure 3 As shown.
[0029] The first-order critical speed of the rotor-bearing system is 15% to 20% higher than the rated operating speed of the CT scanner. In this embodiment, it is 567 rpm, which is much higher than the designed rated operating speed of 300 to 480 rpm. This allows the CT scanner to maintain stable operation at the rated operating speed. The operating speed of the CT scanner, which was originally supported by mechanical bearings at 240 rpm, is gradually doubled to the operating speed of the CT scanner supported by permanent magnet levitation bearings at 480 rpm. Theoretically, this reduces the radiation time of the patient's CT examination by half. The noise level is controlled below 65 dB(A).
[0030] Therefore, this invention adopts the above-mentioned radial permanent magnet levitation bearing system for a high-speed direct-drive CT machine. It innovatively designs an inner and outer ring system similar to a rolling bearing, and combines it with an auxiliary mechanical control protection bearing system. The stator permanent magnet ring is specially processed and then concentrically and clearance-fitted with the rotor permanent magnet ring. Stable levitation of permanent magnet force is achieved through mechanical control, eliminating the need for an electronic control system. This ensures high-speed and stable operation of the CT machine, increases equipment speed and service life, reduces operating noise, and shortens CT examination radiation time. It also lays a theoretical foundation for the research, development, and promotion of magnetic levitation CT machines.
[0031] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and not to limit them. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can still be made to the technical solutions of the present invention, and these modifications or equivalent substitutions cannot cause the modified technical solutions to deviate from the spirit and scope of the technical solutions of the present invention.
Claims
1. A radial permanent magnet levitation bearing system for a high-speed direct-drive CT scanner, characterized in that, Includes stator permanent magnet double half ring (1), rotor permanent magnet ring (2), first outer ring seat (3), left and right auxiliary mechanical control protection bearings (4), first inner ring seat (5), second inner ring seat (6), direct drive CT machine motor rotor (7), direct drive CT machine motor stator (8), and second outer ring seat (9); The stator permanent magnet double half ring (1) is clamped between the outer rings of the left and right auxiliary mechanical control protection bearings (4), and the stator permanent magnet double half ring (1) is embedded in the first outer ring seat (3) and the second outer ring seat (9). The first outer ring seat (3), the stator permanent magnet double half ring (1) and the second outer ring seat (9) are fixed by bolts and together with the outer rings of the left and right auxiliary mechanical control protection bearings (4) form the outer ring system of the radial permanent magnet suspension bearing. The first outer ring seat (3) is an integral seat of the outer ring of the left auxiliary mechanical control protection bearing and the stator permanent magnet double half ring (1). The second outer ring seat (9) is an integral seat of the outer ring of the right auxiliary mechanical control protection bearing and the stator permanent magnet double half ring (1). The rotor permanent magnet ring (2) is clamped between the inner rings of the left and right auxiliary mechanical control protection bearings (4), and the rotor permanent magnet ring (2) is externally embedded on the first inner ring seat (5) and the second inner ring seat (6). The first inner ring seat (5), the rotor permanent magnet ring (2) and the second inner ring seat (6) are fixed by bolts and together with the inner rings of the left and right auxiliary mechanical control protection bearings (4) form the inner ring system of the radial permanent magnet suspension bearing. The first inner ring seat (5) is an integral seat of the inner ring of the left auxiliary mechanical control protection bearing and the rotor permanent magnet ring (2), and the second inner ring seat (6) is an integral seat of the inner ring of the right auxiliary mechanical control protection bearing and the rotor permanent magnet ring (2). The direct-drive CT machine motor rotor (7) is fixedly connected to the second inner ring seat (6) by bolts, that is, the direct-drive CT machine motor rotor (7) is fixedly connected to the inner ring system of the radial permanent magnet suspension bearing; The stator (8) of the direct-drive CT machine motor is fixedly connected to the second outer ring seat (9) by bolts, that is, the stator (8) of the direct-drive CT machine motor is fixedly connected to the outer ring system of the radial permanent magnet suspension bearing.
2. The high-speed direct-drive CT scanner radial permanent magnet levitation bearing system according to claim 1, characterized in that, The stator permanent magnet double half ring (1) is a structure composed of an upper stator permanent magnet ring and a lower stator permanent magnet ring with opposite magnetic poles. The stator permanent magnet double half ring (1) is made by cutting an axially magnetized complete permanent magnet ring into two half rings along the horizontal radial axis of symmetry, and then rotating the upper permanent magnet half ring around the vertical axis by 180 degrees. When the stator permanent magnet double half ring (1) and the axially magnetized rotor permanent magnet ring (2) are in a clearance fit, the upper half attracts the opposite poles and the lower half repels the same poles. The stator permanent magnet double half ring (1) and the rotor permanent magnet ring (2) are in a concentric clearance fit position.
3. The high-speed direct-drive CT scanner radial permanent magnet levitation bearing system according to claim 2, characterized in that, The stator permanent magnet double half ring (1) and the rotor permanent magnet ring (2) have the same width. The rotor permanent magnet ring (2) and the stator permanent magnet double half ring (1) have the same thickness and width. A gap is provided between the stator permanent magnet double half ring (1) and the rotor permanent magnet ring (2). The center diameter of the gap between the stator permanent magnet double half ring (1) and the rotor permanent magnet ring (2) is consistent with the center diameter of the ceramic ball of the left and right auxiliary mechanical control protection bearings (4).
4. The high-speed direct-drive CT scanner radial permanent magnet levitation bearing system according to claim 3, characterized in that, The stator permanent magnet double half ring (1) and the rotor permanent magnet ring (2) are both made of permanent magnet materials and are galvanized. The galvanized layer is uniform, smooth, free of sand holes and peeling.
5. The high-speed direct-drive CT scanner radial permanent magnet levitation bearing system according to claim 1, characterized in that, The left and right auxiliary mechanical control protection bearings (4) are two thin-walled angular contact ceramic ball bearings, and the two thin-walled angular contact ceramic ball bearings are installed face to face. The inner rings of the two thin-walled angular contact ceramic ball bearings are respectively fitted on the seat shafts of the first inner ring seat (5) and the second inner ring seat (6) in a radial transition fit manner. The outer rings are respectively installed in the seat holes of the first outer ring seat (3) and the second outer ring seat (9). The axial end faces of the inner ring and the outer ring respectively abut on the rotor permanent magnet ring (2) and the stator permanent magnet double half ring (1). The bolts of the inner and outer ring systems of the radial permanent magnet suspension bearing are used to apply preload to the two thin-walled angular contact ceramic ball bearings to prevent the ceramic balls of the thin-walled angular contact ceramic ball bearings from slipping, thereby playing the role of auxiliary mechanical control protection.
6. The high-speed direct-drive CT scanner radial permanent magnet levitation bearing system according to claim 1, characterized in that, The first-order bending critical speed of the rotor-bearing system of the radial permanent magnet levitation bearing system is 15% to 20% greater than the rated operating speed of the CT scanner.
7. The high-speed direct-drive CT scanner radial permanent magnet levitation bearing system according to claim 5, characterized in that, The thin-walled angular contact ceramic ball bearing only bears preload and minor external load, serving as an auxiliary positioning, mechanical control, and protection function. The number of its ceramic balls is reduced to 1 / 3 of that of a normal bearing to reduce noise.