Magnetic suspension molecular pump

Abstract

The utility model discloses a magnetic suspension molecular pump, and relates to the technical field of magnetic suspension molecular pumps, a displacement sensor comprises a pump shell, an impeller, a rotor shaft, a magnetic bearing assembly and a hybrid displacement sensor, and a pump cavity is formed in the pump shell; the impeller is rotatably accommodated in the pump cavity; the rotor shaft is arranged in the pump cavity and connected with the impeller to drive the impeller to rotate synchronously. The magnetic bearing assembly comprises an upper radial magnetic bearing and a lower radial magnetic bearing, and the upper radial magnetic bearing and the lower radial magnetic bearing are arranged on the rotor shaft in a sleeving mode at intervals in the axial direction of the rotor shaft. The hybrid displacement sensor sleeves the rotor shaft and is coaxial with the rotor shaft. The hybrid displacement sensor is used for detecting the axial displacement and the radial displacement of the rotor shaft. The utility model aims to improve the integration level of radial and axial displacement sensors and reduce the design cost, the manufacturing cost and the debugging control difficulty of the displacement sensors.

Description

Technical Field

[0001] This utility model relates to the field of magnetic levitation molecular pump technology, and in particular to a magnetic levitation molecular pump. Background Technology

[0002] A magnetic levitation molecular pump is a type of molecular pump that uses magnetic bearings as the rotor support. It uses magnetic bearings to stably suspend the rotor in the air, so that there is no mechanical contact between the rotor and the stator during high-speed operation. It has the advantages of no mechanical wear, low energy consumption, high allowable speed, low noise, long service life, and no need for lubrication. At present, magnetic levitation molecular pumps are widely used in the fields of obtaining high vacuum and high cleanliness vacuum environments.

[0003] A magnetic levitation molecular pump typically includes a pump body and a rotor located inside the pump body. The rotor includes a rotor shaft and an impeller fixedly connected to the rotor shaft. The rotor shaft is equipped with axial magnetic bearings, axial displacement sensors for detecting axial displacement signals of the rotor, radial magnetic bearings, and radial displacement sensors for detecting radial displacement signals of the rotor. In addition, the magnetic levitation molecular pump is also equipped with a controller to control its operation. The controller can calculate and analyze the radial and axial displacements of the rotor based on the output signals of the radial and axial displacement sensors, and then drive the corresponding radial and axial magnetic bearings to output electromagnetic forces to control the radial and axial movements of the rotor.

[0004] However, existing axial sensors are usually probe-type sensors, typically located at the bottom of the pump body, with the end of the rotor shaft as the sensing object. However, probe-type sensors are difficult to design and manufacture, and the magnetic cores they use are relatively fragile, resulting in a high scrap rate during production. In actual whole-machine debugging, they require high compatibility with the control system, making control more difficult. Utility Model Content

[0005] The main purpose of this invention is to propose a displacement sensor, a magnetic bearing assembly, an axial clearance adjustment mechanism, and a magnetic levitation molecular pump, aiming to improve the integration of radial and axial displacement sensors and reduce the design cost, manufacturing cost, and debugging and control difficulty of displacement sensors.

[0006] To achieve the above objectives, this utility model proposes a magnetically levitated molecular pump, comprising:

[0007] Pump casing, wherein a pump chamber is formed inside the pump casing;

[0008] An impeller, which is rotatably housed within the pump chamber;

[0009] A rotor shaft is disposed inside the pump chamber and is connected to the impeller to drive the impeller to rotate synchronously;

[0010] A magnetic bearing assembly, comprising an upper radial magnetic bearing and a lower radial magnetic bearing, wherein the upper and lower radial magnetic bearings are axially spaced and sleeved on the rotor shaft; and

[0011] A hybrid displacement sensor is sleeved on the rotor shaft and coaxially arranged with the rotor shaft. The hybrid displacement sensor is used to detect the axial displacement and radial displacement of the rotor shaft.

[0012] In one embodiment, the magnetic bearing assembly further includes a magnetic bearing housing, which is sleeved on the rotor shaft and coaxially arranged with the rotor shaft. The hybrid displacement sensor and the lower radial magnetic bearing are both fixedly mounted on the magnetic bearing housing.

[0013] In one embodiment, a mounting groove is formed on one end face of the magnetic bearing housing, and a first shaft hole is formed on the other end face of the magnetic bearing housing, which communicates with the mounting groove and is used to mount the rotor shaft; from the opening of the mounting groove toward the first shaft hole, a first mounting ring platform and a second mounting ring platform are provided at intervals along the axial direction of the rotor shaft on the inner sidewall of the mounting groove; the first mounting ring platform is used to mount the lower radial magnetic bearing; the second mounting ring platform is used to mount the hybrid displacement sensor.

[0014] In one embodiment, the first mounting ring has a first connecting hole, and the end face of the lower radial magnetic bearing has a first mounting hole; the magnetic bearing assembly further includes a first locking member, the locking end of the first locking member passing through the first mounting hole and locked within the first connecting hole; and / or

[0015] The second mounting ring has a second connecting hole, and the hybrid displacement sensor has a through second mounting hole; the magnetic bearing assembly also includes a second locking member, the locking end of the second locking member passing through the second mounting hole and locked in the second connecting hole.

[0016] In one embodiment, the magnetically levitated molecular pump further includes a base and an adjustment structure. The base has a second shaft hole for mounting the rotor shaft. The magnetic bearing seat is disposed on the base and spaced apart from the base in the axial direction of the rotor shaft. The adjustment structure is used to adjust the distance between the magnetic bearing seat and the base in the axial direction of the rotor shaft.

[0017] In one embodiment, the base includes a first seat body and a guide seat connected to the first seat body. The guide seat has a second shaft hole, a plurality of third locking holes and an annular groove on its end face near the magnetic bearing seat. The plurality of third locking holes are evenly spaced around the second shaft hole along the axial direction of the rotor shaft.

[0018] The magnetic bearing housing has multiple through-hole third mounting holes on its end face away from the guide seat, and the multiple third mounting holes are connected to the multiple third locking holes one by one.

[0019] The adjustment structure includes a wave spring and a plurality of third locking elements. The wave spring is housed in the annular groove and abuts against the end of the magnetic bearing seat near the guide seat. Each of the third locking elements is inserted into a third mounting hole and locked in a third locking hole.

[0020] In one embodiment, the magnetic bearing housing includes a second housing and a plurality of mounting arms. A portion of the second housing is inserted into the second shaft hole. The second housing has a first shaft hole coaxially arranged with the second shaft hole. The plurality of mounting arms are spaced apart along the axial direction of the rotor shaft on the outer peripheral wall of the second housing. The mounting arms have the third mounting hole.

[0021] In one embodiment, the hybrid displacement sensor includes two sensor stators, each sensor stator including an iron core ring and a plurality of magnetic poles. The plurality of magnetic poles extend circumferentially along the inner peripheral wall of the iron core ring toward the rotor shaft. The plurality of magnetic poles include a plurality of radial teeth arranged axially symmetrically and a plurality of axial teeth arranged axially symmetrically.

[0022] The core ring has a first end face and a second end face. Two sensor stators are stacked axially on the rotor shaft. The first end face of the core ring of one sensor stator faces the second end face of the core ring of the other sensor stator. A radial tooth of one sensor stator and a radial tooth of the other sensor stator are combined to form a radial detection module. An axial tooth of one sensor stator and an axial tooth of the other sensor stator are combined to form an axial detection module.

[0023] In one embodiment, the radial tooth portion includes two radial teeth, and the axial tooth is disposed between two adjacent radial tooth portions and close to one of the radial tooth portions;

[0024] In the radial detection module, the two radial teeth of one radial tooth section correspond one-to-one with the two radial teeth of another radial tooth section and are stacked; in the axial detection module, the two axial teeth are staggered in the axial direction of the rotor shaft.

[0025] In one embodiment, the hybrid displacement sensor is located at one end of the rotor shaft near the lower radial magnetic bearing.

[0026] The magnetic levitation molecular pump provided by this invention utilizes a coaxially mounted hybrid displacement sensor on the rotor shaft to simultaneously monitor both radial and axial displacements. This design eliminates the need for complex sensing probes installed at the bottom of the pump body, thus avoiding the design challenges and high manufacturing costs associated with probe-type sensors. Furthermore, by integrating the detection functions of radial and axial displacements into a single sensor, the number of sensors required is reduced, simplifying the assembly process and system structure, lowering potential failure points, and resulting in a more compact, efficient, and reliable overall design. In addition, since the entire machine commissioning process does not require individual calibration of multiple sensors, assembly is quicker and simpler, further improving production efficiency and maintenance convenience. In summary, the magnetic levitation molecular pump provided by this invention has significant advantages in improving system integration, reducing manufacturing costs, and enhancing commissioning convenience. Attached Figure Description

[0027] To more clearly illustrate the technical solutions in the embodiments of this utility model or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this utility model. For those skilled in the art, other drawings can be obtained based on the structures shown in these drawings without creative effort.

[0028] Figure 1 A schematic diagram of a structural embodiment of the magnetic levitation molecular pump provided by this utility model;

[0029] Figure 2 for Figure 1 Enlarged view of point A in the image;

[0030] Figure 3 This is a schematic diagram of a structure of an embodiment of the magnetic bearing assembly provided by this utility model;

[0031] Figure 4 A schematic diagram of another embodiment of the magnetic levitation molecular pump provided by this utility model;

[0032] Figure 5 This is a schematic diagram of a structure of an embodiment of the hybrid displacement sensor provided by this utility model;

[0033] Figure 6 This is a schematic diagram of the axial displacement detection principle of the hybrid displacement sensor provided by this utility model.

[0034] Explanation of icon numbers:

[0035] 1000. Magnetic levitation molecular pump; 1. Impeller; 2. Rotor shaft; 3. Magnetic bearing assembly; 31. Upper radial magnetic bearing; 32. Lower radial magnetic bearing; 33. Magnetic bearing housing; 331. Second housing; 332. Mounting arm; 333. First mounting ring platform; 334. Second mounting ring platform; 335. First shaft hole; 4. Hybrid displacement sensor; 41. Sensor stator; 411. Iron core ring; 412. Magnetic pole; 4121. Radial teeth; 412 1a. Radial tooth; 4122. Axial tooth; 42. Radial detection module; 43. Axial detection module; 44. Winding frame; 5. Base; 51. First seat; 52. Guide seat; 53. Second shaft hole; 54. Annular groove; 6. Adjustment structure; 61. Third locking element; 62. Wave spring; 7. Upper protective bearing; 8. Radial displacement sensor; 9. Motor; 10. Thrust bearing; 11. Lower protective bearing; 12. Impeller cylinder; 13. Motor housing.

[0036] The realization of the purpose, functional features and advantages of this utility model will be further explained in conjunction with the embodiments and with reference to the accompanying drawings. Detailed Implementation

[0037] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present utility model.

[0038] It should be noted that if the embodiments of this utility model involve directional indicators (such as up, down, left, right, front, back, etc.), the directional indicators are only used to explain the relative positional relationship and movement of the components in a specific posture. If the specific posture changes, the directional indicators will also change accordingly.

[0039] Furthermore, if the embodiments of this utility model involve descriptions such as "first" or "second," these descriptions are for descriptive purposes only and should not be construed as indicating or implying their relative importance or implicitly specifying the number of technical features indicated. Therefore, a feature defined with "first" or "second" may explicitly or implicitly include at least one of those features. Additionally, the use of "and / or" or "and / or" throughout the text includes three parallel solutions. For example, "A and / or B" includes solution A, solution B, or a solution where both A and B are satisfied simultaneously. Furthermore, the technical solutions of the various embodiments can be combined with each other, but this must be based on the ability of those skilled in the art to implement them. When the combination of technical solutions is contradictory or impossible to implement, it should be considered that such a combination of technical solutions does not exist and is not within the scope of protection claimed by this utility model.

[0040] This invention proposes a magnetic levitation molecular pump 1000.

[0041] Please see Figure 1 In one embodiment of this utility model, the magnetic levitation molecular pump 1000 includes a pump casing, an impeller 1, a rotor shaft 2, a magnetic bearing assembly 3, and a hybrid displacement sensor 4. The pump casing has a pump cavity formed inside. The impeller 1 is rotatably housed in the pump cavity. The rotor shaft 2 is disposed in the pump cavity and connected to the impeller 1 to drive the impeller 1 to rotate synchronously. The magnetic bearing assembly 3 includes an upper radial magnetic bearing 31 and a lower radial magnetic bearing 32, which are spaced apart along the axial direction of the rotor shaft 2. The hybrid displacement sensor 4 is sleeved on the rotor shaft 2 and coaxially arranged with the rotor shaft 2. The hybrid displacement sensor 4 is used to detect the axial displacement and radial displacement of the rotor shaft 2.

[0042] The magnetic levitation molecular pump 1000 provided by this invention, by setting a hybrid displacement sensor 4 coaxially on the rotor shaft 2, can simultaneously monitor the radial and axial displacements of the rotor shaft 2. This design eliminates the need for complex sensing probes that need to be installed at the bottom of the pump body, thus avoiding the design difficulties and high manufacturing costs associated with probe-type sensors. Furthermore, by integrating the detection functions of radial and axial displacements into a single sensor, not only is the number of sensors required reduced, but the assembly process and system structure are also simplified, reducing potential failure points and making the overall design more compact, efficient, and reliable. In addition, since the whole machine debugging process does not require individual calibration of multiple sensors, the assembly of the whole machine is faster and simpler, further improving production efficiency and maintenance convenience. In summary, the magnetic levitation molecular pump 1000 provided by this invention has significant advantages in improving system integration, reducing manufacturing costs, and enhancing debugging convenience.

[0043] It is known that the upper radial magnetic bearing 31 and the lower radial magnetic bearing 32 are located at the upper and lower ends of the rotor shaft 2, respectively, to support and stabilize the radial movement of the rotor. The upper radial magnetic bearing 31 is located at the upper end of the rotor shaft 2, usually near the pump inlet, and mainly bears the radial force from above the impeller 1. The lower radial magnetic bearing 32 is located at the lower end of the rotor shaft 2, usually near the pump outlet, and mainly bears the radial force from below the impeller 1. To achieve the best levitation effect, the upper radial magnetic bearing 31 and the lower radial magnetic bearing 32 are usually designed as a symmetrical structure to balance the radial force of the rotor. It should be added that the magnetic levitation molecular pump 1000 usually also includes components such as the upper protective bearing 7, the radial displacement sensor 8, the motor 9, the thrust bearing 10, the lower protective bearing 11, the impeller cylinder 12, and the motor housing 13, which together constitute the core of the magnetic levitation molecular pump 1000. Each part undertakes a specific function to ensure that the pump can operate efficiently and stably.

[0044] It should be noted that the hybrid displacement sensor 4 is a sensor that integrates axial and radial displacement detection functions. It can simultaneously or separately measure the axial and radial displacement changes of the rotor shaft 2 in a single sensor structure. The design of this type of sensor usually combines the axial and radial detection mechanisms to achieve accurate measurement of multidimensional displacement. For example, the hybrid displacement sensor 4 can be an inductive displacement sensor. Inductive displacement sensors use the interaction between a coil and a magnetic material to detect displacement. Typically, the coil is fixed at one end of the sensor, while a magnetic target is fixed on the measuring shaft. When the shaft undergoes axial displacement, the position of the magnetic target changes relative to the coil, thereby changing the inductance value of the coil. Of course, the hybrid displacement sensor 4 can also detect displacement through probes (such as capacitive probes, inductive probes, etc.). For example, two piezoelectric or photoelectric probes can be used, respectively installed in two directions perpendicular to the measured shaft. The contact between the probe and the measured target or changes in optical signals can be converted into displacement signals.

[0045] In many rotating machines, the center of gravity of the rotor shaft 2 is typically located at the bottom. Therefore, in one embodiment, the hybrid displacement sensor 4 is located at the end of the rotor shaft 2 near the lower radial magnetic bearing. This allows for better monitoring of displacement changes due to gravity and rapid feedback to the control system, enabling timely adjustment of the magnetic bearing torque to maintain shaft stability. Of course, in other embodiments, the hybrid displacement sensor 4 can also be positioned at other locations on the rotor shaft 2. However, it is important to ensure that the installation location of the hybrid displacement sensor 4 has sufficient space, does not interfere with other components, and is installed in a location that facilitates maintenance and replacement.

[0046] Please see Figure 3In one embodiment, the magnetic bearing assembly 3 may further include a magnetic bearing housing 33, which is sleeved on and coaxially arranged with the rotor shaft 2. The hybrid displacement sensor 4 and the lower radial magnetic bearing 32 are both fixedly mounted on the magnetic bearing housing 33. Specifically, the magnetic bearing housing 33 serves as a support and fixing component, providing a stable mounting platform for the hybrid displacement sensor 4 and the lower radial magnetic bearing 32. Since the hybrid displacement sensor 4 and the lower radial magnetic bearing 32 are both mounted on the same magnetic bearing housing 33, not only are assembly steps reduced and assembly difficulty lowered, but the relative position between the hybrid displacement sensor 4 and the lower radial magnetic bearing 32 can also be precisely controlled. This helps to improve the measurement accuracy of the sensor and the control effect of the magnetic bearing.

[0047] Furthermore, to improve assembly stability, in one embodiment, a mounting groove is provided on one end face of the magnetic bearing housing 33, and a first shaft hole 335 for mounting the rotor shaft 2 is provided on the other end face of the magnetic bearing housing 33, which connects to the mounting groove. From the opening of the mounting groove towards the first shaft hole 335, a first mounting ring platform 333 and a second mounting ring platform 334 are provided at axial intervals along the rotor shaft 2 on the inner sidewall of the mounting groove. The first mounting ring platform 333 is used to mount the lower radial magnetic bearing 32; the second mounting ring platform 334 is used to mount the hybrid displacement sensor 4. The first mounting ring platform 333 is specifically used to mount the lower radial magnetic bearing 32, ensuring its stable mounting on the magnetic bearing housing 33, thereby effectively supporting the lower end of the rotor shaft 2 and preventing radial displacement during operation. The second mounting ring platform 334 is used to mount the hybrid displacement sensor 4, allowing the sensor to be precisely mounted at a predetermined position on the rotor shaft 2 for accurate monitoring of the rotor's radial and axial displacement, thereby improving the axial positioning accuracy of the entire system.

[0048] In other embodiments, in addition to using a mounting ring to mount the lower radial magnetic bearing 32 and the hybrid displacement sensor 4, a special fixture can be designed to fix them. The fixture can surround or clamp the lower radial magnetic bearing 32 and the hybrid displacement sensor 4 to ensure that their positions are fixed, or the lower radial magnetic bearing 32 and the hybrid displacement sensor 4 can be directly welded to the magnetic bearing seat 33.

[0049] To facilitate the inspection, maintenance, and disassembly of the magnetic bearing assembly 3, in one embodiment, the first mounting ring 333 has a first connecting hole, and the end face of the lower radial magnetic bearing 32 has a first mounting hole; the magnetic bearing assembly 3 also includes a first locking member, the locking end of which passes through the first mounting hole and is locked within the first connecting hole. In another embodiment, the second mounting ring 334 has a second connecting hole, and the hybrid displacement sensor 4 has a through-hole second mounting hole; the magnetic bearing assembly 3 also includes a second locking member, the locking end of which passes through the second mounting hole and is locked within the second connecting hole. In other embodiments, the above two implementation methods can coexist. Among them, the first locking element and the second locking element refer to a type of mechanical component used to fix or prevent relative movement of components, ensuring that the components do not loosen when subjected to external forces or vibrations, thereby maintaining the stability of the structure and the normal operation of the equipment. The first locking element and the second locking element are usually screws or bolts. By using the locking elements, not only is a firm connection between the lower radial magnetic bearing 32 and the hybrid displacement sensor 4 and the magnetic bearing seat 33 ensured, reducing relative movement during operation and improving the stability of the overall structure, but the lower radial magnetic bearing 32 and the hybrid displacement sensor 4 can also be quickly disassembled and reinstalled when maintenance is required, thus improving maintenance efficiency.

[0050] Considering that the axial position of the hybrid displacement sensor 4 needs to be adjusted during actual assembly to ensure its detection accuracy, please refer to [link to relevant documentation]. Figure 2 and Figure 4 In one embodiment, the magnetic levitation molecular pump 1000 further includes a base 5 and an adjustment structure 6. The base 5 has a second shaft hole 53 for mounting the rotor shaft 2. A magnetic bearing seat 33 is disposed on the base 5 and spaced apart from the base 5 in the axial direction of the rotor shaft 2 (generally with a clearance of about 1 mm on each side). The adjustment structure 6 is used to adjust the distance between the magnetic bearing seat 33 and the base 5 in the axial direction of the rotor shaft 2. It should be noted that the base 5 is the basic component of the pump, and its main function is to provide support and fixation for the rotor shaft 2 and other components. The shaft hole on the base 5 can ensure the accurate assembly position of the rotor shaft 2 and ensure the assembly accuracy of the pump. The main function of the adjustment structure 6 is to adjust the distance between the magnetic bearing seat 33 and the base 5 in the axial direction of the rotor shaft 2, thereby realizing the precise adjustment of the axial position of the hybrid displacement sensor 4. Assembly workers can quickly and accurately adjust the sensor position, reducing assembly time and difficulty.

[0051] Furthermore, the adjustment structure 6 can be a combination of springs and fasteners. The springs adjust and maintain a certain preload or position to preload the magnetic bearing seat 33 into a fixed position, and then the fasteners are used for locking, allowing the magnetic bearing seat 33 to move and be fixed axially on the rotor shaft 2. Specifically, in one embodiment, the base 5 includes a first seat body 51 and a guide seat 52 connected to the first seat body 51. The guide seat 52 has a second shaft hole 53, multiple third locking holes, and an annular groove 54 on its end face near the magnetic bearing seat 33. A number of third locking holes are evenly spaced around the second shaft hole 53 along the axial direction of the rotor shaft 2. Multiple through-hole third mounting holes are provided on the end face of the magnetic bearing seat 33 facing away from the guide seat 52, and these holes correspond one-to-one with the third locking holes. The adjustment structure 6 includes a wave spring 62 and multiple third locking elements 61. The wave spring 62 is housed in the annular groove 54 and abuts against the end of the magnetic bearing seat 33 near the guide seat 52. Each third locking element 61 is inserted into a corresponding third mounting hole and locked within that hole. Thus, during initial installation, the magnetic bearing seat 33 is tightened onto the mating surface of the guide seat 52 using the third locking elements 61. At this time, the wave spring 62 is in a compressed state. After the rotor shaft 2 is assembled, axial clearance adjustment can be performed. The rotor is moved to check the axial sensor parameters in the background. Based on the parameter results, the third locking elements 61 are loosened or tightened. At this time, under the action of the wave spring 62, the magnetic bearing seat 33 generates axial displacement, which drives the hybrid displacement sensor 4 to move. The third locking element refers to a type of mechanical component used to fix or prevent relative movement of parts, ensuring that the assembly does not loosen when subjected to external force or vibration, thereby maintaining the stability of the structure and the normal operation of the equipment. The third locking element is usually a screw or bolt. It should be noted that during the adjustment process, the number of turns of the multiple third locking elements 61 must be consistent. In this way, the axial position adjustment of the hybrid displacement sensor 4 can be quickly completed by directly observing the change in the rotor's single-sided displacement data. In general, the structural scheme of adjusting the axial displacement of the sensor using spring force avoids the frequent disassembly and assembly operations when adjusting the clearance of the rotor shaft 2 of the magnetic levitation molecular pump 1000, and improves the convenience of axial position adjustment of the hybrid sensor. In other embodiments, mounting holes can also be opened on the mating surface of the guide seat 52, and a helical spring can be placed in the mounting hole to achieve the same function. However, under the condition of providing the same elastic force, the helical spring requires more installation space, while the wave spring 62 can provide greater elastic force in a smaller space. Of course, depending on the application scenario and production cost, the adjustment structure 6 can also use an electric actuator, hydraulic cylinder, or pneumatic cylinder as the drive structure for adjustment.

[0052] In one embodiment, the magnetic bearing housing 33 includes a second base 331 and a plurality of mounting arms 332. Part of the structure of the second base 331 is inserted into a second shaft hole 53. The second base 331 has a first shaft hole 335 coaxially arranged with the second shaft hole 53. The plurality of mounting arms 332 are spaced apart along the axial direction of the rotor shaft 2 on the outer peripheral wall of the second base 331. The mounting arms 332 have third mounting holes. The design of the mounting arms 332 allows the magnetic bearing housing 33 to be firmly fixed on the guide seat 52, while providing stable support for the lower radial magnetic bearing 32 and the hybrid displacement sensor 4. In addition, the third mounting holes on the mounting arms 332 allow for fine adjustment of the distance between the magnetic bearing housing 33 and the base 5 by adjusting the position of the mounting arms 332, thereby achieving precise adjustment of the axial position of the sensor. In order to further improve the installation stability, in other embodiments, the guide seat 52 may also be provided with a limiting groove corresponding to the mounting arm 332, and a third locking hole is provided at the bottom of the limiting groove. This design can ensure the correct position of the mounting arm 332 on the guide seat 52 and prevent it from moving during the installation process.

[0053] Please continue to refer to the following information. Figure 3 The motor housing 13 generally needs to be locked and installed with the base 5. In order to facilitate the adjustment of the position of the magnetic bearing seat 33, in one embodiment, the motor housing 13 is provided with a notch at the position of the mounting arm 332 of the magnetic bearing seat 33. The third locking member 61 can be inserted through the notch. In this way, when it is necessary to loosen or tighten the third locking member 61, the position of the magnetic bearing seat 33 can be adjusted without disassembling the motor housing 13, which greatly simplifies the maintenance and debugging process.

[0054] Please see Figure 5In one embodiment, the hybrid displacement sensor 4 includes two sensor stators 41. Each sensor stator 41 includes an iron core ring 411 and a plurality of magnetic poles 412. The plurality of magnetic poles 412 extend circumferentially along the inner peripheral wall of the iron core ring 411 toward the rotor shaft 2. Each magnetic pole 412 includes a plurality of radial teeth 4121 and a plurality of axial teeth 4122 arranged symmetrically in the axial direction. The iron core ring 411 has a first end face and a second end face. The two sensor stators 41 are stacked axially on the rotor shaft 2. The first end face of the iron core ring 411 of one sensor stator 41 faces the second end face of the iron core ring 411 of the other sensor stator 41. A radial tooth 4121 of one sensor stator 41 is combined with a radial tooth 4121 of the other sensor stator 41 to form a radial detection module 42. An axial tooth 4122 of one sensor stator 41 is combined with an axial tooth 4122 of the other sensor stator 41 to form an axial detection module 43. It should be noted that the hybrid displacement sensor 4 is an inductive displacement sensor. The teeth are a series of protruding toothed parts on the iron core ring 411, which are usually made of magnetic material. In actual use, the teeth need to cooperate with the coil. When current passes through the coil, a magnetic field is generated in the teeth and can interact with the rotor shaft 2 made of magnetic material. When the rotor shaft 2 has radial or axial displacement, the area of ​​the rotor shaft 2 corresponding to the radial teeth 4121 or axial teeth 4122 changes, causing the inductance to change. Through differential design, the axial or radial displacement change can be obtained by monitoring the voltage in the circuit, so that the hybrid displacement sensor 4 can calculate the displacement of the rotor shaft 2 by detecting these changes.

[0055] Furthermore, in one embodiment, the radial tooth 4121 includes two radial teeth 4121a, and the axial tooth 4122 is disposed between two adjacent radial teeth 4121 and close to one radial tooth 4121. In the radial detection module 42, two radial teeth 4121a of one radial tooth section 4121 correspond one-to-one with two radial teeth 4121a of another radial tooth section 4121 and are stacked. It should be noted that the two stacked radial teeth 4121a form a set of radial test teeth. When the rotor shaft 2 is centered, the areas of the rotor shaft 2 corresponding to the two sets of radial test teeth are the same, and the inductance of the two sets of radial test teeth is the same. However, when the rotor has radial displacement, the areas of the rotor shaft 2 facing the two sets of radial test teeth change. At this time, the area facing one set of radial test teeth increases, and the area facing the other set decreases. That is, in terms of inductance, the inductance of one set of radial test teeth increases, and the inductance of the other set decreases. Through differential design, radial displacement can be monitored by voltage monitoring in the circuit. (See also...) Figure 6In the axial detection module 43, two axial teeth 4122 are offset axially on the rotor shaft 2. When the rotor shaft 2 is centered, Z1=Z2, and the areas of the rotor shaft 2 corresponding to the two axial teeth 4122 are the same. At this time, the inductance of the two axial teeth 4122 is the same. However, when the rotor has axial displacement, the areas of the rotor shaft 2 opposite to the two axial teeth 4122 change. At this time, the area opposite to one axial tooth 4122 increases, and the area opposite to the other axial tooth 4122 decreases. That is, in terms of inductance, the inductance of one axial tooth 4122 increases, and the inductance of the other axial tooth 4122 decreases. Through differential design, axial displacement can be monitored by voltage monitoring in the circuit.

[0056] In one embodiment, the hybrid displacement sensor 4 further includes multiple winding frames 44, each winding frame 44 corresponding to the outer side of four radial teeth 4121a of a radial detection module 42 or the outer side of two axial teeth 4122 of an axial detection module. It is understood that the magnetic field generated by the winding coil interacts with the magnetic portion of the rotor, achieving displacement detection through electromagnetic coupling. The winding frame 44 supports and fixes the winding coil, ensuring its stability under high-speed operation and high-temperature environments, preventing deformation or detachment. Furthermore, the winding frame 44 provides electrical isolation, preventing short circuits between the winding coils and protecting the coils from external factors.

[0057] The above description is merely an exemplary embodiment of the present utility model and does not limit the patent scope of the present utility model. Any equivalent structural transformations made based on the technical concept of the present utility model and the contents of the present utility model specification and drawings, or direct / indirect applications in other related technical fields, are included within the patent protection scope of the present utility model.

Claims

1. A magnetically levitated molecular pump, characterized in that, include: Pump casing, wherein a pump chamber is formed inside the pump casing; An impeller, which is rotatably housed within the pump chamber; A rotor shaft is disposed inside the pump chamber and is connected to the impeller to drive the impeller to rotate synchronously; A magnetic bearing assembly, comprising an upper radial magnetic bearing and a lower radial magnetic bearing, wherein the upper and lower radial magnetic bearings are axially spaced and sleeved on the rotor shaft; and A hybrid displacement sensor is sleeved on the rotor shaft and coaxially arranged with the rotor shaft. The hybrid displacement sensor is used to detect the axial displacement and radial displacement of the rotor shaft.

2. The magnetically levitated molecular pump as described in claim 1, characterized in that, The magnetic bearing assembly also includes a magnetic bearing housing, which is sleeved on the rotor shaft and coaxially arranged with the rotor shaft. The hybrid displacement sensor and the lower radial magnetic bearing are fixedly installed on the magnetic bearing housing.

3. The magnetically levitated molecular pump as described in claim 2, characterized in that, One end face of the magnetic bearing housing is provided with a mounting groove, and the other end face of the magnetic bearing housing is provided with a first shaft hole that communicates with the mounting groove and is used to install the rotor shaft; from the opening of the mounting groove toward the first shaft hole, the inner sidewall of the mounting groove is provided with a first mounting ring platform and a second mounting ring platform spaced apart along the axial direction of the rotor shaft; the first mounting ring platform is used to install the lower radial magnetic bearing; the second mounting ring platform is used to install the hybrid displacement sensor.

4. The magnetically levitated molecular pump as described in claim 3, characterized in that, The first mounting ring has a first connecting hole, and the end face of the lower radial magnetic bearing has a first mounting hole; the magnetic bearing assembly further includes a first locking member, the locking end of the first locking member passing through the first mounting hole and locked within the first connecting hole; and / or The second mounting ring has a second connecting hole, and the hybrid displacement sensor has a through second mounting hole; the magnetic bearing assembly also includes a second locking member, the locking end of the second locking member passing through the second mounting hole and locked in the second connecting hole.

5. The magnetically levitated molecular pump as described in claim 2, characterized in that, The magnetic levitation molecular pump further includes a base and an adjustment structure. The base has a second shaft hole for mounting the rotor shaft. The magnetic bearing seat is disposed on the base and spaced apart from the base in the axial direction of the rotor shaft. The adjustment structure is used to adjust the distance between the magnetic bearing seat and the base in the axial direction of the rotor shaft.

6. The magnetically levitated molecular pump as described in claim 5, characterized in that, The base includes a first seat body and a guide seat connected to the first seat body. The guide seat has a second shaft hole, a plurality of third locking holes and an annular groove on its end face near the magnetic bearing seat. The plurality of third locking holes are evenly spaced around the second shaft hole along the axial direction of the rotor shaft. The magnetic bearing housing has multiple through-hole third mounting holes on its end face away from the guide seat, and the multiple third mounting holes are connected to the multiple third locking holes one by one. The adjustment structure includes a wave spring and a plurality of third locking elements. The wave spring is housed in the annular groove and abuts against the end of the magnetic bearing seat near the guide seat. Each of the third locking elements is inserted into a third mounting hole and locked in a third locking hole.

7. The magnetically levitated molecular pump as described in claim 6, characterized in that, The magnetic bearing housing also includes a second housing and a plurality of mounting arms. A portion of the structure of the second housing is inserted into the second shaft hole. The second housing has a first shaft hole coaxially arranged with the second shaft hole. The plurality of mounting arms are spaced apart along the axial direction of the rotor shaft on the outer peripheral wall of the second housing. The mounting arms have the third mounting hole.

8. The magnetically levitated molecular pump according to any one of claims 1 to 7, characterized in that, The hybrid displacement sensor includes two sensor stators, each sensor stator including an iron core ring and multiple magnetic poles. The multiple magnetic poles extend circumferentially along the inner circumferential wall of the iron core ring toward the rotor shaft. The multiple magnetic poles include multiple radial teeth arranged axially symmetrically and multiple axial teeth arranged axially symmetrically. The core ring has a first end face and a second end face. Two sensor stators are stacked axially on the rotor shaft. The first end face of the core ring of one sensor stator faces the second end face of the core ring of the other sensor stator. A radial tooth of one sensor stator and a radial tooth of the other sensor stator are combined to form a radial detection module. An axial tooth of one sensor stator and an axial tooth of the other sensor stator are combined to form an axial detection module.

9. The magnetically levitated molecular pump as described in claim 8, characterized in that, The radial tooth portion includes two radial teeth, and the axial tooth is disposed between two adjacent radial tooth portions and close to one of the radial tooth portions; In the radial detection module, the two radial teeth of one radial tooth section correspond one-to-one with the two radial teeth of another radial tooth section and are stacked; in the axial detection module, the two axial teeth are staggered in the axial direction of the rotor shaft.

10. The magnetically levitated molecular pump according to any one of claims 1 to 7, characterized in that, The hybrid displacement sensor is located at one end of the rotor shaft near the lower radial magnetic bearing.

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