Counterweight structure and molecular pump

Abstract

The utility model relates to a counter weight structure and molecular pump, including: shell, motor casing, shaft, rotor, stator and stators, the inside of shell is fixedly connected with the stator, the rotor is located in the stator, the rotor is fixedly connected with the shaft in the rotor, the motor casing is located between the shaft and the rotor and fixed with the position of shell, and the motor casing is fixed with the position of shell. The interior of the motor shell is fixedly connected with a stator, and the stator drives a rotating shaft to rotate. The first threaded holes and the second threaded holes are formed in the balance plate in the circumferential direction, the screws with different weights are in threaded connection with the balance plate, the screws can be replaced conveniently to change the balance weight to achieve dynamic balance in the test process, and the problem that the balance weight of a rotor needs to be changed by grinding a balance weight piece of a molecular pump is solved.

Description

Technical Field

[0001] The utility model relates to the field of molecular pumps, in particular to a counterweight structure and a molecular pump. Background Art

[0002] Molecular vacuum pumps (molecular pumps) have become the mainstream equipment in the fields of clean high vacuum and ultra-high vacuum applications because of their stable and reliable operation and good pumping efficiency under molecular flow conditions. They are widely used in scientific instruments and industrial production equipment.

[0003] When the molecular pump is balanced and debugged, the counterweight needs to be polished to change the weight of the rotor. This debugging method is inefficient and the metal debris generated can easily cause pollution to the surrounding environment and the inside of the molecular pump. Utility Model Content

[0004] The utility model aims to solve the above problems, provides a counterweight structure and a molecular pump, and solves the problem that the molecular pump needs to grind the counterweight to change the counterweight of the rotor.

[0005] A counterweight structure comprises: a balance plate and a first screw, wherein a plurality of first threaded holes are formed on the top of the balance plate, the first threaded holes are evenly arranged in a circle, and the first screw is threadedly connected to the first threaded holes.

[0006] Based on the above technical solution, the balance plate is a rotating body, and the first threaded holes are evenly arranged in a circle with the rotating axis of the balance plate as the center.

[0007] Based on the above technical solution, it also includes a second screw, and the balance board is further formed with a second threaded hole, the second screw is threadedly connected to the second threaded hole, the second threaded holes are evenly arranged in a circle with the rotation axis of the balance board as the center, and the distance from the second threaded hole to the rotation axis of the balance board is greater than the distance from the first threaded hole to the rotation axis of the balance board.

[0008] Based on the above technical solution, each first threaded hole corresponds to a second threaded hole in the radial direction, and at least one second threaded hole is arranged between the second threaded holes corresponding to two adjacent first threaded holes in the radial direction.

[0009] Based on the above technical solution, the weight of the first screw is greater than the weight of the second screw.

[0010] Based on the above technical solution, the inner diameter of the first threaded hole is larger than the inner diameter of the second threaded hole.

[0011] A molecular pump using the counterweight structure comprises: a shell, a motor shell, a rotating shaft, a rotor, a stator and a stator, wherein the interior of the shell is fixedly connected to the stator, the rotor is located inside the stator, the rotor is fixedly connected to the rotating shaft inside the stator, the motor shell is located between the rotating shaft and the rotor and is fixed to the position of the shell, the interior of the motor shell is fixedly connected to the stator, the stator drives the rotating shaft to rotate, the balance plate is fixedly connected to the rotating shaft and / or the rotor, and the rotating shaft, the rotor and the balance plate are coaxial.

[0012] Based on the above technical solution, it also includes a base, which is located below the shell and fixedly connected to the shell, the interior of the base is respectively connected to the exhaust port and the interior of the shell, and the motor housing is fixedly connected to the base.

[0013] On the basis of the above technical solution, it also includes at least two magnetic bearings, which are respectively mounted on the outside of the rotating shaft, the magnetic bearings are fixedly connected to the motor housing, and an X-axis displacement sensor and a Y-axis displacement sensor are arranged inside the magnetic bearings;

[0014] On the basis of the above technical solution, it also includes an upper electromagnet, a spacer ring, a lower electromagnet and a floating plate, the lower part of the rotating shaft is fixedly connected to the floating plate, the upper electromagnet and the lower electromagnet are respectively located on the upper and lower sides of the floating plate, the upper electromagnet and the lower electromagnet are respectively fixedly connected to the motor housing, the spacer ring is located between the upper electromagnet and the lower electromagnet and is in contact with the upper electromagnet and the lower electromagnet respectively;

[0015] On the basis of the above technical solution, it also includes a Z-axis sensor base, which is located below the rotating shaft and fixed relative to the motor housing, and a Z-axis displacement sensor is installed above the Z-axis sensor base.

[0016] On the basis of the above technical solution, it also includes an air guide ring, which is fixedly connected to the base and has a threaded plate formed inside.

[0017] The utility model has the following advantages: screws of different weights are respectively threadedly connected to the balance plate through the first threaded hole and the second threaded hole circumferentially arranged on the balance plate, so that it is convenient to replace the screws to change the counterweight to achieve dynamic balance during the test, and solves the problem that the molecular pump needs to grind the counterweight to change the counterweight of the rotor. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] In order to more clearly illustrate the embodiments of the utility model or the technical solutions in the prior art, the drawings required for use in the embodiments or the prior art descriptions are briefly introduced below. Obviously, the drawings described below are only one embodiment of the utility model. For ordinary technicians in this field, other implementation drawings can be derived from the provided drawings without creative work.

[0019] Figure 1 : A schematic diagram of the three-dimensional structure of the utility model;

[0020] Figure 2 : A schematic diagram of the top view of the structure of the utility model;

[0021] Figure 3 : Figure 2 Schematic diagram of the cross-sectional structure at AA in the middle. DETAILED DESCRIPTION

[0022] The utility model is further described below with reference to the accompanying drawings and examples:

[0023] The embodiments of the present invention are described in detail below, and examples of the embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present invention, and cannot be understood as limiting the present invention.

[0024] In the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be directly connected or indirectly connected through an intermediate medium. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0025] In the description of the present invention, it should be understood that the terms "upper", "lower", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", etc., indicating orientations or positional relationships, are based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present invention.

[0026] Embodiment 1:

[0027] like Figures 1 to 3 As shown, this embodiment provides a counterweight structure, including: a balance plate 20 and a first screw, a plurality of first threaded holes 201 are formed on the top of the balance plate 20, the first threaded holes 201 are evenly arranged around the circumference, and the first screw is threadedly connected to the first threaded holes 201.

[0028] When the balancing plate 20 has only the first threaded hole 201 , when performing weight balancing, it is necessary to thread and fix the weight-grinded screw to the first threaded hole 201 to achieve dynamic balancing.

[0029] Based on the above technical solution, the balancing plate 20 is a rotating body, and the first threaded holes 201 are evenly arranged in a circle with the rotating axis of the balancing plate 20 as the center.

[0030] On the basis of the above technical solution, a second screw is further included, and the balancing board 20 is further formed with a second threaded hole 202, the second screw is threadedly connected to the second threaded hole 202, the second threaded holes 202 are evenly arranged in a circle with the rotation axis of the balancing board 20 as the center, and the distance from the second threaded hole 202 to the rotation axis of the balancing board 20 is greater than the distance from the first threaded hole 201 to the rotation axis of the balancing board 20.

[0031] Based on the above technical solution, each first threaded hole 201 has a corresponding second threaded hole 202 in the radial direction, and at least one second threaded hole 202 is provided between the second threaded holes 202 corresponding to two adjacent first threaded holes 201 in the radial direction.

[0032] Based on the above technical solution, the weight of the first screw is greater than the weight of the second screw.

[0033] Based on the above technical solution, the inner diameter of the first threaded hole 201 is greater than the inner diameter of the second threaded hole 202 .

[0034] The inner diameter of the second threaded hole 202 is smaller than the inner diameter of the first threaded hole 201, and the depth of the second threaded hole 202 is smaller than the depth of the first threaded hole 201. The weights of the screws adapted to the first threaded hole 201 and the second threaded hole 202 are not equal. When balancing weights, two screws of different weights, two different radii, and the angles between the two screws and the center of the circle are matched, so that the torque can be accurately controlled without grinding the screws, so that the rotor 5 reaches a balanced state.

[0035] A molecular pump using the counterweight structure comprises: a housing 2, a motor housing 3, a rotating shaft 4, a rotor 5, a stator 6 and a stator 7, wherein the interior of the housing 2 is fixedly connected to the stator 6, the rotor 5 is located inside the stator 6, the rotor 5 is fixedly connected to the rotating shaft 4 inside the stator 6, the motor housing 3 is located between the rotating shaft 4 and the rotor 5 and is fixed to the housing 2, the interior of the motor housing 3 is fixedly connected to the stator 7, the stator 7 drives the rotating shaft 4 to rotate, the balancing plate 20 is fixedly connected to the rotating shaft 4 and / or the rotor 5, and the rotating shaft 4, the rotor 5 and the balancing plate 20 are coaxial.

[0036] Based on the above technical solution, it also includes a base 1, which is located below the shell 2 and fixedly connected to the shell 2. The interior of the base 1 is respectively connected to the exhaust port 18 and the interior of the shell 2, and the motor housing 3 is fixedly connected to the base 1.

[0037] On the basis of the above technical solution, it also includes at least two magnetic bearings 8, which are respectively mounted on the outside of the rotating shaft 4, and the magnetic bearings 8 are fixedly connected to the motor housing 3, and an X-axis displacement sensor and a Y-axis displacement sensor are arranged inside the magnetic bearings 8;

[0038] On the basis of the above technical solution, it also includes an upper electromagnet 11, a spacer ring 12, a lower electromagnet 13 and a floating plate 14, the lower part of the rotating shaft 4 is fixedly connected to the floating plate 14, the upper electromagnet 11 and the lower electromagnet 13 are respectively located on the upper and lower sides of the floating plate 14, the upper electromagnet 11 and the lower electromagnet 13 are respectively fixedly connected to the motor housing 3, the spacer ring 12 is located between the upper electromagnet 11 and the lower electromagnet 13 and is in contact with the upper electromagnet 11 and the lower electromagnet 13 respectively;

[0039] On the basis of the above technical solution, a Z-axis sensor base 15 is further included. The Z-axis sensor base 15 is located below the rotating shaft 4 and is fixed relative to the motor housing 3 . A Z-axis displacement sensor is installed above the Z-axis sensor base 15 .

[0040] On the basis of the above technical solution, it further comprises an air guide ring 17 , which is fixedly connected to the base 1 , and a threaded plate 171 is formed inside the air guide ring 17 .

[0041] During operation, the flange on the upper part of the housing 2 is fixedly connected and communicated with the vacuum container, and the exhaust port 18 is communicated with the front pump. The stator 7 drives the shaft 4 to rotate through magnetic force (the principle is the same as that of the motor). At low speed, the step surface at the lower part of the shaft 4 contacts the upper end surface of the inner ring of the lower bearing 9, and the lower bearing 9 carries the shaft 4. When the speed gradually increases, the upper electromagnet 11 and the lower electromagnet 13 drive the floating plate 14 to move axially through magnetic force, and the two axially arranged magnetic bearings 8 drive the shaft 4 to move radially, so that the shaft 4 and the rotor 5 are suspended. The resistance of the suspended shaft 4 is greatly reduced, so as to achieve a high speed.

[0042] The first turbine blade 502 rotates at a high speed relative to the second turbine blade 603 to draw in gas molecules. The gas molecules pass through the turbine section and then go down into the spiral grooves between the threaded plates 171. Under the traction of the spiral grooves, the gas molecules are finally discharged from the exhaust port 18 to the front pump.

[0043] The present invention is described above by way of examples, but the present invention is not limited to the above specific embodiments, and any changes or modifications based on the present invention belong to the scope of protection required by the present invention.

Claims

1. A counterweight structure, characterized in that: include: A balance plate (20) and a first screw, wherein a plurality of first threaded holes (201) are formed on the top of the balance plate (20), the first threaded holes (201) are evenly arranged in a circle, and the first screw is threadedly connected to the first threaded holes (201).

2. A counterweight structure according to claim 1, characterized in that: The balancing plate (20) is a rotating body, and the first threaded holes (201) are evenly arranged in a circle with the rotating axis of the balancing plate (20) as the center.

3. A counterweight structure according to claim 2, characterized in that: The balance plate (20) further comprises a second screw, the balance plate (20) further comprising a second threaded hole (202), the second screw being threadedly connected to the second threaded hole (202), the second threaded holes (202) being evenly arranged in a circle with the rotation axis of the balance plate (20) as the center, and the distance between the second threaded hole (202) and the rotation axis of the balance plate (20) being greater than the distance between the first threaded hole (201) and the rotation axis of the balance plate (20).

4. A counterweight structure according to claim 3, characterized in that: Each first threaded hole (201) has a second threaded hole (202) corresponding in the radial direction, and at least one second threaded hole (202) is arranged between the second threaded holes (202) corresponding in the radial direction of two adjacent first threaded holes (201).

5. A counterweight structure according to claim 3, characterized in that: The weight of the first screw is greater than the weight of the second screw.

6. A counterweight structure according to claim 3, characterized in that: The inner diameter of the first threaded hole (201) is greater than the inner diameter of the second threaded hole (202).

7. A molecular pump using the counterweight structure according to any one of claims 1 to 6, characterized in that: include: A housing (2), a motor housing (3), a rotating shaft (4), a rotor (5), a stator (6) and a stator (7); the interior of the housing (2) is fixedly connected to the stator (6); the rotor (5) is located inside the stator (6); the rotor (5) is fixedly connected to the rotating shaft (4) inside the stator (6); the motor housing (3) is located between the rotating shaft (4) and the rotor (5) and is fixed to the housing (2); the interior of the motor housing (3) is fixedly connected to the stator (7); the stator (7) drives the rotating shaft (4) to rotate; the balancing plate (20) is fixedly connected to the rotating shaft (4) and / or the rotor (5); the rotating shaft (4), the rotor (5) and the balancing plate (20) are coaxial.

8. A molecular pump according to claim 7, characterized in that: It also comprises a base (1), the base (1) being located below the outer shell (2) and fixedly connected to the outer shell (2), the interior of the base (1) being respectively connected to the exhaust port (18) and the interior of the outer shell (2), and the motor housing (3) being fixedly connected to the base (1).

9. A molecular pump according to claim 7, characterized in that: It also comprises at least two magnetic bearings (8), the two magnetic bearings (8) are respectively mounted on the outside of the rotating shaft (4), the magnetic bearings (8) are fixedly connected to the motor housing (3), and an X-axis displacement sensor and a Y-axis displacement sensor are arranged inside the magnetic bearings (8); It also comprises an upper electromagnet (11), a spacer ring (12), a lower electromagnet (13) and a floating plate (14); the lower portion of the rotating shaft (4) is fixedly connected to the floating plate (14); the upper electromagnet (11) and the lower electromagnet (13) are respectively located on the upper and lower sides of the floating plate (14); the upper electromagnet (11) and the lower electromagnet (13) are respectively fixedly connected to the motor housing (3); the spacer ring (12) is located between the upper electromagnet (11) and the lower electromagnet (13) and is respectively in contact with the upper electromagnet (11) and the lower electromagnet (13); It also comprises a Z-axis sensor base (15), wherein the Z-axis sensor base (15) is located below the rotating shaft (4) and is fixed relative to the motor housing (3), and a Z-axis displacement sensor is installed above the Z-axis sensor base (15).

10. A molecular pump according to claim 8, characterized in that: It also comprises an air guide ring (17), wherein the air guide ring (17) is fixedly connected to the base (1), and a threaded plate (171) is formed inside the air guide ring (17).

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