Molecular pump multi-surface balance debugging device

Abstract

The invention provides a molecular pump multi-face balance debugging device which comprises a vacuum cavity assembly used for providing a vacuum environment; the pump body assembly is mounted in the vacuum cavity assembly through a pump body fixing seat; the pump body assembly comprises a process pump shell and a rotor assembly arranged in the process pump shell. The rotor assembly consists of a main shaft and blades fixed on the main shaft, and is supported on the bearing seat through a bearing; the rotor assembly is provided with at least four groups of balance weight surfaces along the axial direction of a main shaft of the rotor assembly, and threaded holes for mounting balance nails are uniformly distributed in each group of balance weight surfaces; a kidney-shaped groove is formed in the position, corresponding to each set of balance weight faces, of the side wall of the process pump shell, and a tool can stretch into the kidney-shaped groove to operate the balance nails. The dynamic balance debugging range of the molecular pump rotor is expanded, the debugging precision is improved, meanwhile, operation is easy, and efficiency is high.

Description

Technical Field

[0001] This invention relates to the field of high vacuum acquisition equipment research and development and production, specifically to a molecular pump multi-faceted balancing and debugging device. Background Technology

[0002] Molecular pumps, as mainstream vacuum-generating devices, provide clean high vacuum and have a wide range of applications. They operate at high speeds, particularly the instrumental molecular pump involved in this invention, which exceeds 60,000 rpm, classifying it as ultra-high-speed rotating machinery. During research and production, dynamic balancing is required through weight reduction or addition to minimize initial imbalance and reduce vibration during acceleration and full-speed operation. Due to material limitations, the molecular pump rotor must be under vacuum during high-speed dynamic balancing.

[0003] The current practice involves designing the process pump casing with two rings of evenly distributed screw holes on the rotor side. Corresponding to these screw holes are two openings on the side of the process pump casing (these openings can be sealed with blind flanges during molecular pump operation). During high-speed commissioning of the molecular pump, the pump is evacuated to a vacuum state by the backing pump. An imbalance test is then performed at this speed. The pump is then stopped, and balancing pins are added. This process is repeated multiple times until the vibration meets requirements. However, in actual operation, it has been found that due to machining errors and material inhomogeneity, the initial imbalance often exceeds the compensation limit of the two-ring counterweight structure. Because of the existing structural design, it is impossible to add more counterweights, leading to balancing failures or excessive residual vibration, affecting the reliability of the molecular pump and failing to meet current industry requirements. Summary of the Invention

[0004] To address the shortcomings of existing technologies, the purpose of this invention is to provide a molecular pump multi-faceted balancing and debugging device.

[0005] A molecular pump multi-faceted balancing adjustment device provided by the present invention includes: Vacuum chamber assembly, used to provide a vacuum environment; A pump body assembly, which is mounted inside the vacuum chamber assembly via a pump body mounting base; The pump body assembly includes a process pump casing and a rotor assembly disposed therein. The rotor assembly consists of a main shaft and blades fixed thereon, and is supported on a bearing housing via bearings; The rotor assembly is provided with at least four sets of counterweight surfaces along the axial direction of its main shaft, and each set of counterweight surfaces is provided with threaded holes for mounting counterweight pins. On the side wall of the process pump casing, corresponding to the position of each set of balance weight surfaces, there is a waist-shaped groove for tools to be inserted to operate the balance pin.

[0006] Preferably, the vacuum chamber assembly is provided with a vacuum penetration socket for electrically connecting the motor driver and high-speed dynamic balancing instrument located outside the vacuum chamber to the motor stator and vibration sensor inside the pump body assembly.

[0007] Preferably, a mechanical dry pump is connected to the vacuum chamber assembly via a bellows for evacuating the vacuum chamber assembly.

[0008] Preferably, the pump body assembly is an integral structure, in which the process pump housing, rotor assembly, bearing housing and motor stator are assembled into one unit before being installed into the vacuum chamber assembly.

[0009] Preferably, the at least four sets of counterweight surfaces are arranged in parallel along the axis of the main shaft.

[0010] Preferably, the bearing housing is provided with a side damping ring and an axial damping ring.

[0011] Preferably, the vacuum chamber assembly includes a vacuum chamber and a vacuum chamber sealing cover, and the vacuum chamber sealing cover is provided with a sealing cover handle.

[0012] Preferably, the vacuum chamber and the vacuum chamber sealing cover are sealed by an O-ring.

[0013] Compared with the prior art, the present invention has the following beneficial effects: 1. This invention provides more counterweight positions and a larger counterweight radius selection by using at least four sets of counterweight surfaces axially aligned with the rotor assembly, compared to the traditional structure with only two counterweight surfaces. This significantly increases the initial imbalance that the device can compensate for, effectively solving the problem of excessive initial imbalance due to machining errors and material inhomogeneity, thereby improving the success rate of dynamic balancing.

[0014] 2. In this invention, the vacuum chamber provides a vacuum environment through a mechanical dry pump, ensuring the rotor operates at full speed. A vacuum chamber penetration socket ensures the motor driver and high-speed balancing instrument can connect and operate normally. The pump body assembly is installed as a single unit before being fixed to the vacuum chamber, ensuring the rotor's rotational accuracy. Multiple evenly distributed screw holes are arranged along the rotor's axis, which, compared to the traditional two-circle hole arrangement, can balance even larger imbalances and further improve adjustment accuracy. A waist-shaped groove is cut on the process pump casing to ensure processability and ease of operation. This invention expands the dynamic balancing adjustment range of the molecular pump rotor, improves adjustment accuracy, and is simple and efficient to operate.

[0015] 3. The present invention provides a waist-shaped groove on the side wall of the process pump casing corresponding to each set of counterweight surfaces, so that the operator can install or adjust the balance pins by reaching into the pump casing with tools without having to disassemble the vacuum chamber and pump body components every time the commissioning is performed. Attached Figure Description

[0016] Other features, objects, and advantages of the present invention will become more apparent from the following detailed description of non-limiting embodiments with reference to the accompanying drawings: Figure 1 This is a schematic diagram of a molecular pump multi-faceted balancing and debugging device provided in an embodiment of the present invention.

[0017] Explanation of reference numerals in the attached figures: 1. Vacuum chamber; 2. Vacuum chamber sealing cover; 3. Sealing cover handle; 4. Process pump housing; 5. Central column; 6. Upper bearing; 7. Main shaft; 8. Blade; 9. Carbon fiber tube; 10. Motor stator; 11. Motor rotor; 12. Balance ring; 13. Stator mounting base; 14. Bearing housing; 15. Lower bearing; 16. Side damping ring; 17. Axial damping ring; 18. Pump body mounting base; 19. Vibration sensor; 20. Vacuum chamber penetration socket; 21. Vacuum KF interface; 22. Bellows; 23. Mechanical dry pump; 24. Motor driver; 25. High-speed dynamic balancing instrument. Detailed Implementation

[0018] The present invention will now be described in detail with reference to specific embodiments. These embodiments will help those skilled in the art to further understand the present invention, but do not limit the invention in any way. It should be noted that those skilled in the art can make several changes and improvements without departing from the concept of the present invention. These all fall within the protection scope of the present invention.

[0019] This invention provides a multi-faceted balancing and debugging device for a molecular pump. The vacuum chamber 1 provides a vacuum environment via a mechanical dry pump 23, ensuring the rotor assembly operates at full speed. A vacuum penetration socket 20 ensures the normal connection and operation of the motor driver 24 and the high-speed dynamic balancing instrument 25. The pump body assembly is integrally installed and then fixed to the vacuum chamber 1, ensuring the rotational accuracy of the rotor. The rotor has multiple axially arranged balancing threaded holes, which, compared to the traditional two-turn structure, can compensate for a larger initial imbalance and improve debugging accuracy. A waist-shaped groove is opened on the process pump casing 4 to facilitate tool insertion and improve operational efficiency. This invention expands the dynamic balancing debugging range of the molecular pump rotor, improves debugging accuracy, and is simple and efficient to operate.

[0020] like Figure 1 As shown, the molecular pump multi-faceted balancing and debugging device provided in this embodiment mainly includes a vacuum chamber assembly, a pump body assembly, a vacuum chamber socket 20, a vacuum KF interface 21, a bellows 22, a high-speed dynamic balancing instrument 25, a motor driver 24, and a mechanical dry pump 23.

[0021] The vacuum chamber assembly consists of a vacuum chamber 1, a vacuum chamber sealing cover 2, and a sealing cover handle 3. This vacuum chamber assembly acts as a sealed container, providing the necessary vacuum environment for the high-speed operation of the molecular pump rotor. The vacuum chamber 1 is typically a square container made of 304 stainless steel, offering good vacuum performance and structural strength. The vacuum chamber sealing cover 2 achieves a vacuum seal with the vacuum chamber 1 via an O-ring. The sealing cover handle 3 is welded to the vacuum chamber sealing cover 2, facilitating the opening and closing of the sealing cover by the operator.

[0022] The pump body assembly is mounted and fixed inside the vacuum chamber 1 via the pump body mounting base 18. The pump body assembly is the core of the entire device. Its core components are pre-assembled into a whole before being installed into the vacuum chamber 1 to ensure the rotational accuracy of the rotor during operation. This assembly mainly includes the process pump casing 4, the central column 5, the upper bearing 6, the rotor assembly, the motor stator 10, the motor rotor 11, the balance ring 12, the stator mounting base 13, the bearing housing 14, the lower bearing 15, the side damping ring 16, the axial damping ring 17, and the vibration sensor 19.

[0023] The rotor assembly consists of a main shaft 7, blades 8, and carbon fiber tubes 9. The main shaft 7 is supported on a bearing housing 14 via an upper bearing 6 and a lower bearing 15. The motor stator 10 and the motor rotor 11 constitute the drive unit, driving the rotor assembly to rotate. The side damping rings 16 and axial damping rings 17 provided on the bearing housing 14 have the same constraint form as the actual molecular pump to simulate the dynamic characteristics under real working conditions.

[0024] The key improvement of this invention lies in the fact that the rotor assembly has at least four sets of balancing counterweight surfaces along its main shaft 7, and each set of balancing counterweight surfaces is evenly distributed with multiple threaded holes for installing balancing pins. Correspondingly, elongated slots are formed on the side wall of the process pump casing 4, corresponding to the position of each set of balancing counterweight surfaces. These slots allow for the installation or adjustment of balancing pins on any designated counterweight surface using a special tool, without shutting down the entire pump body during disassembly, greatly improving operational efficiency.

[0025] To establish a vacuum environment and drive the system, the mechanical dry pump 23 serves as a backing pump, connected to the vacuum KF interface 21 on the vacuum chamber 1 via the bellows 22, for evacuating the vacuum chamber 1. The vacuum chamber penetration socket 20 is installed on the wall of the vacuum chamber 1, with its internal wires passing through the vacuum chamber wall, for electrically connecting the motor driver 24 and high-speed dynamic balancing instrument 25 located outside the vacuum chamber to the motor stator 10 and vibration sensor 19 inside the vacuum chamber, thereby ensuring normal operation of the equipment and signal testing in a vacuum environment.

[0026] The vibration sensor 19 is typically installed on the upper and lower sides of the pump body assembly to collect vibration data when the rotor rotates at high speed and transmit it to the high-speed dynamic balancer 25.

[0027] The working process of the multi-faceted balancing and debugging device for a molecular pump provided by the present invention is as follows: In actual operation, first, the vacuum chamber sealing cover 2 is closed and sealed, and the mechanical dry pump 23 is started to evacuate the vacuum chamber 1. Once the required vacuum level is reached, the rotor assembly is accelerated to the predetermined test speed by the external motor driver 24. During this process, the vibration sensor 19 monitors the vibration in real time and transmits the data to the high-speed dynamic balancing instrument 25. The high-speed dynamic balancing instrument 25 analyzes the data to determine the phase and magnitude of the rotor imbalance.

[0028] Subsequently, the system was shut down, and the vacuum chamber sealing cover 2 was opened. Based on the analysis results, the operator used tools to install or adjust the balance pins on the corresponding balance weight surface through the corresponding slot on the process pump casing 4. After completion, the vacuum chamber was sealed again, and the above process of vacuuming, acceleration, and testing was repeated. This cycle was repeated until the rotor vibration level reached the design requirements.

[0029] In the description of this application, it should be understood that the terms "upper", "lower", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this application.

[0030] Specific embodiments of the present invention have been described above. It should be understood that the present invention is not limited to the specific embodiments described above, and those skilled in the art can make various changes or modifications within the scope of the claims, which do not affect the essence of the present invention. Unless otherwise specified, the embodiments and features described in this application can be arbitrarily combined with each other.

Claims

1. A molecular pump multi-faceted balancing and adjustment device, characterized in that, include: Vacuum chamber assembly, used to provide a vacuum environment; The pump body assembly is mounted inside the vacuum chamber assembly via a pump body mounting base (18); The pump body assembly includes a process pump casing (4) and a rotor assembly disposed therein; The rotor assembly consists of a main shaft (7) and blades (8) fixed thereon, and is supported on a bearing housing (14) via bearings; The rotor assembly is provided with at least four sets of counterweight surfaces along its main shaft (7), and each set of counterweight surfaces is provided with threaded holes for installing counterweight pins. On the side wall of the process pump casing (4), corresponding to the position of each set of balance weight surfaces, there is a waist-shaped groove for tools to be inserted to operate the balance nail.

2. The molecular pump multi-faceted balancing and debugging device according to claim 1, characterized in that, The vacuum chamber assembly is provided with a vacuum penetration socket (20) for electrically connecting the motor driver (24) and the high-speed dynamic balancer (25) located outside the vacuum chamber to the motor stator (10) and vibration sensor (19) inside the pump body assembly.

3. The molecular pump multi-faceted balancing and adjustment device according to claim 1, characterized in that, A mechanical dry pump (23) is connected to the vacuum chamber assembly via a bellows (22) for evacuating the vacuum chamber assembly.

4. The molecular pump multi-faceted balancing and debugging device according to claim 1, characterized in that, The pump body assembly is an integral structure, which has assembled the process pump housing (4), rotor assembly, bearing housing (14) and motor stator (10) into one unit before being installed into the vacuum chamber assembly.

5. The molecular pump multi-faceted balancing and adjustment device according to claim 1, characterized in that, The at least four sets of balancing counterweight surfaces are arranged parallel to each other along the main shaft (7).

6. The molecular pump multi-faceted balancing and debugging device according to claim 1, characterized in that, The bearing housing (14) is provided with a side damping ring (16) and an axial damping ring (17).

7. The molecular pump multi-faceted balancing and adjustment device according to claim 1, characterized in that, The vacuum chamber assembly includes a vacuum chamber (1) and a vacuum chamber sealing cover (2), and the vacuum chamber sealing cover (2) is provided with a sealing cover handle (3).

8. The molecular pump multi-faceted balancing and adjustment device according to claim 7, characterized in that, The vacuum chamber (1) and the vacuum chamber sealing cover (2) are sealed by an O-ring.

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