Metal ceramic ultra-smooth screw vacuum pump device

Abstract

The invention discloses a metal ceramic ultra-smooth screw vacuum pump device, and belongs to the technical field of vacuum pumps. In order to solve the problems that in the operation process of a current micro-oil screw vacuum pump, the lubricating effect of a synchronous high-speed reverse rotating screw contact interface is poor, abrasion is serious, and efficient, stable and safe operation of an oil-free screw vacuum pump cannot be guaranteed, the surface of a screw metal matrix is coated with a metal ceramic layer with a certain thickness; a microstructure is additionally arranged on the surface of a metal ceramic layer, trace water and lubricating oil in high-speed rotating compressed gas are filled in the microstructure on the surface of the metal ceramic, and a water-oil lubricating film is formed on the rough meshing surface of the metal ceramic screw under the action of fluid dynamic pressure, so that the rough meshing surface of the metal ceramic super-smooth screw is separated, and the roughness coefficient of the meshing surface is reduced; and the super-smooth effect is achieved. The vacuum pump can meet the requirements for high-grade vacuum pumps in the technical fields of medical pharmacy, national defense military industry, semiconductors, chemical industry and the like.

Description

Technical Field

[0001] The invention relates to the technical field of vacuum pumps, and in particular to a metal ceramic super-smooth screw vacuum pump device. Background Art

[0002] A micro-oil screw vacuum pump is a power device that uses a high-speed synchronous counter-rotating screw to convert low-pressure gas into high-pressure gas. It has a relatively large compression ratio and is widely used in medical and pharmaceutical, national defense and military industry, textile, chemical, semiconductor and refrigeration fields. The screw gap plays a decisive role in the compression ratio. Reducing the gap can increase the compression ratio of the vacuum pump. However, too small a gap causes friction and wear of the screw, which seriously affects the service life. Therefore, controlling the screw gap and maintaining the lubrication effect are technical problems that need to be solved during the design, production and use of micro-oil screw vacuum pumps. In order to reduce the harm to the friction and wear of the screw, the patent (202223319447.4) discloses a variable frequency energy-saving and low-noise oil-free screw vacuum pump, whose lubricating oil cooling circulation system uses an oil pump to pump oil into the cooling system and then transport it to the oil-free screw vacuum pump, and then returns to the oil tank through the return oil pipe after passing through the rear teeth and bearings of the pump body. Although the harm of screw friction and wear can be alleviated, external components need to be added, which increases the risk and cost of oil leakage. The patent (application number: 202223319447.4) discloses an ordered microporous wear-resistant self-lubricating coating and its preparation method. The laser cladding technology is used to directly form an ordered microporous (aperture 200μm) nickel-based hard coating on the surface of a titanium alloy substrate, and then the soft metal lubricant SnAg alloy and the negative expansion material ZrW2O8 as a regulator are melt-infiltrated into the micropores of the nickel-based hard coating by high-temperature infiltration technology to form a wear-resistant self-lubricating coating. Although the coating has a wear-reducing effect, the friction coefficient is greater than 0.2, which still affects the performance and life. In order to further reduce the friction coefficient of the screw joint surface, the present invention proposes a metal ceramic super-smooth screw vacuum pump device, a metal ceramic coating is coated on the screw substrate, and a microstructure is added to the surface of the metal ceramic coating by a picosecond laser processing process, so that the metal ceramic super-smooth screw meshing surface generates a water-oil lubricating film, achieving a super-smooth effect (friction coefficient is less than 0.0012), ensuring the efficient, stable and safe operation of the oil-free screw vacuum pump, and having important practical application value. Summary of the invention

[0003] The present invention aims at the problem that the synchronous high-speed reverse rotating screw of the existing micro-oil screw vacuum pump is seriously worn and cannot ensure the efficient, stable and safe operation of the oil-free screw vacuum pump. A metal ceramic super-smooth screw vacuum pump device is proposed. A metal ceramic layer of a certain thickness is coated on the surface of the screw metal substrate, and a microstructure is added to the surface of the metal ceramic layer. By using the fluid dynamic lubrication theory, a water-oil lubrication film is formed on the meshing surface of the metal ceramic super-smooth screw, the screw meshing surface is separated, friction is reduced, and the super-smooth effect is achieved.

[0004] A metal ceramic super-smooth screw vacuum pump device of the present invention comprises an air inlet, an exhaust port, a pump housing, an end cover and a pair of metal ceramic super-smooth screws that mesh with each other and rotate synchronously in opposite directions; the screw comprises an active screw and a driven screw; the metal ceramic super-smooth screw structure comprises a metal matrix layer and a metal ceramic layer, and a microstructure is provided on the surface of the metal ceramic; the metal material of the metal ceramic layer in the metal ceramic super-smooth screw is Al, Cu or Al-Cu alloy soft metal material, the ceramic is silicon nitride, aluminum oxide or silicon dioxide material, and the metal mass proportion in the metal ceramic is 50%-80%; the microstructure has a depth of 30-50μm, a width of 30-50μm, a spacing of 50-100μm, and the microstructure is evenly distributed.

[0005] A metal ceramic super-smooth screw vacuum pump device of the present invention can achieve super-smooth effect by the following steps:

[0006] (1) An external motor drives the active screw of the vacuum pump to rotate at high speed, and the driven screw meshes with the active screw and rotates at high speed driven by the active screw;

[0007] (2) The gas outside the pump body enters the pump body from the air inlet. The inhaled gas contains a small amount of water and mixes with the small amount of lubricating oil in the pump body;

[0008] (3) The meshing and high-speed rotating metal-ceramic super-smooth screws drive the water-oil-gas mixture into the screw meshing surface, filling the metal-ceramic surface microstructure. Due to the fluid dynamic pressure, a water-oil lubricating film is formed on the rough meshing surface of the metal-ceramic screw, which separates the rough meshing surface of the metal-ceramic super-smooth screw, reduces the roughness coefficient of the meshing surface, and achieves a super-smooth effect.

[0009] The beneficial effects of the present invention are as follows: 1. The metal ceramic super-smooth screw vacuum pump device described in the present invention has a metal ceramic coating on the screw substrate and an additional microstructure. When the vacuum pump is running at high speed, it inhales air. Under the action of the fluid dynamic pressure, trace amounts of water and oil in the air form a water-oil lubricating film on the screw meshing surface, so that the rough meshing surface of the metal ceramic super-smooth screw is separated, the roughness coefficient of the meshing surface is reduced, excessive friction is avoided, and a super-smooth effect is achieved. 2. The formed water-oil lubricating film fills the gap between the screw meshing surfaces, prevents air from entering each pitch space, and improves the operating stability of the vacuum pump. 3. The process of drying and filtering the gas at the air inlet is reduced, and the water vapor damage is converted into a lubricating and friction-reducing medium, which can reduce the cost of the device. BRIEF DESCRIPTION OF THE DRAWINGS

[0010] Figure 1 It is a schematic diagram of the structure of a metal ceramic super-smooth screw vacuum pump device in an embodiment of the present invention.

[0011] Figure 2 Schematic diagram of the metal ceramic super-smooth screw structure in an embodiment of the present invention.

[0012] Figure 3 Schematic diagram of the surface microstructure of the metal ceramic super-smooth screw in an embodiment of the present invention.

[0013] Figure 4 2 is a data diagram of friction coefficient and wear rate in an embodiment of the present invention. DETAILED DESCRIPTION

[0014] Embodiment 1

[0015] (1) A metal ceramic super-smooth screw vacuum pump device comprises an air inlet (1-1), an exhaust port (1-2), a pump housing (1-3), an end cover (1-4), and a pair of metal ceramic super-smooth screws (1-5) that mesh with each other and rotate synchronously in opposite directions, wherein the screws (1-5) comprise a driving screw (1-6) and a driven screw (1-7), and the structure of the screws (1-5) comprises a metal matrix layer (2-1), a metal ceramic layer (2-2), and a microstructure (2-3) is provided on the surface of the metal ceramic; the metal material of the metal ceramic layer (2-2) is Al metal material, the ceramic is silicon nitride material, and the metal mass proportion in the metal ceramic is 50%; the screw is a circular microstructure metal ceramic super-smooth screw (3-1); the microstructure has a depth of 30 μm, a width of 30 μm, a spacing of 50 μm, and the microstructure is evenly distributed;

[0016] (2) An external motor drives the active screw (1-6) of the vacuum pump to rotate at high speed, and the driven screw (1-7) meshes with the active screw (1-6) and rotates at high speed under the drive of the active screw (1-6);

[0017] (3) The gas outside the pump body enters the pump body from the air inlet (1-1). The inhaled gas contains a small amount of water and mixes with the small amount of lubricating oil in the pump body;

[0018] (4) The mutually meshing and high-speed rotating metal-ceramic super-smooth screws (1-5) drive the water-oil-gas mixture into the screw meshing surface, filling the metal-ceramic surface microstructure. Due to the fluid dynamic pressure, a water-oil lubricating film is formed on the meshing rough surface of the metal-ceramic screw, so that the meshing rough surface of the metal-ceramic super-smooth screw (1-5) is separated, the friction coefficient of the meshing surface is lower than 0.001, and the wear rate is lower than 2.2×10-6mm3N-1m-1.

Claims

1. A metal ceramic super-smooth screw vacuum pump device, characterized in that: The device comprises an air inlet (1-1), an air outlet (1-2), a pump housing (1-3), an end cover (1-4), and a pair of metal ceramic super-smooth screws (1-5) that mesh with each other and rotate synchronously in opposite directions. The screws (1-5) comprise a driving screw (1-6) and a driven screw (1-7). The structure of the screws (1-5) comprises a metal matrix layer (2-1) and a metal ceramic layer (2-2). The metal ceramic surface is provided with a microstructure (2-3).

2. A metal ceramic super-smooth screw vacuum pump device according to claim 1, characterized in that: The metal material of the metal ceramic layer (2-2) in the metal ceramic super-smooth screw (1-5) is Al, Cu or Al-Cu alloy soft metal material, the ceramic is silicon nitride, aluminum oxide or silicon dioxide material, and the metal mass proportion in the metal ceramic is 50%-80%.

3. The metal ceramic super-smooth screw vacuum pump device according to claim 1, characterized in that: The metal ceramic super-smooth screw (1-5) is divided into a circular microstructure metal ceramic super-smooth screw (3-1), an elliptical microstructure metal ceramic super-smooth screw (3-2), a rectangular microstructure metal ceramic super-smooth screw (3-3), and a conical microstructure metal ceramic super-smooth screw (3-4) according to the cross-sectional shape of its metal ceramic surface microstructure (2-3).

4. The metal ceramic super-smooth screw vacuum pump device according to claim 1, characterized in that: The microstructure (2-3) on the surface of the metal ceramic super-smooth screw has a depth of 30-50 μm, a width of 30-50 μm, a spacing of 50-100 μm, and the microstructure is evenly distributed.

5. The metal ceramic super-smooth screw vacuum pump device according to claim 1, characterized in that: The device achieves the super-slip effect by the following steps: (1) An external motor drives a vacuum pump driving screw (1-6) to rotate at high speed, and a driven screw (1-7) meshes with the driving screw (1-6) and rotates at high speed under the drive of the driving screw (1-6); (2) The gas outside the pump body enters the pump body from the air inlet (1-1). The inhaled gas contains a small amount of water and mixes with the small amount of lubricating oil in the pump body; (3) The mutually meshing and high-speed rotating metal-ceramic super-smooth screws (1-5) drive the water-oil-gas mixture into the screw meshing surface, filling the metal-ceramic surface microstructure. Due to the fluid dynamic pressure, a water-oil lubricating film is formed on the meshing rough surface of the metal-ceramic screw, so that the meshing rough surface of the metal-ceramic super-smooth screw (1-5) is separated, the meshing surface roughness coefficient is reduced, and the super-smooth effect is achieved.

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