Stator element and high-vacuum pump

[0020] In the illustrated embodiment, the high vacuum pump has a turbo molecular pump 10. The turbomolecular pump 10 has a rotor 16 arranged on a bearing 14 in a housing 12. The rotor 16 has a plurality of rotor elements 18 each having a plurality of rotor blades. A stator element 20 is arranged between the rotor elements 18 and is fixed in the housing 12 via a stator ring 22. By means of the turbomolecular pump 10, the gas is conveyed in the conveying direction 26 through the pump inlet 24.

[0021] A housing element 28 is connected to the housing 12 of the turbomolecular pump 10. The housing element 28 has a stator connecting piece 32 on its inner side 30. The stator connecting piece 32 is arranged directly adjacent to the last rotor element in the conveying direction 26, so that no further intermediate elements, in particular no stator element, are provided between the last rotor element 18 and the stator connecting piece 32.

[0022] A rotor hub 38 configured in a cylindrical shape is fixedly connected to the last rotor element 18 so that the rotor hub 38 rotates with the rotor 16. The stator connecting piece 32 surrounds the rotor hub 38.

[0023] In the illustrated embodiment, the housing element 28 has a flange 34 via which the housing element 28 is connected to the housing 12 of the turbomolecular pump by means of bolts 36.

[0024] In the illustrated embodiment, the inner side 30 of the housing element 28 is evenly distributed with six stator connecting pieces ( figure 2 ). The stator connecting pieces 32 inclined corresponding to the part of the threaded ring respectively extend over about one-quarter to one-third of the entire circumference, and the adjacent stator connecting pieces 32 overlap by about 55%, respectively.

[0025] The stator connecting piece has a radial depth t ( figure 1 ), the radial depth is greater than the mean free path length of the gas particles to be transported. In the illustrated embodiment, the depth t is 10 mm to 20 mm. In the illustrated preferred embodiment, the depth t decreases in the conveying direction. Therefore, the depth t of the area of ​​the stator connecting piece 32 directly adjacent to the last rotor element 1 Depth t in the area farther from the last rotor element 2 Deeper. The pitch or orientation of the respective stator connecting pieces 32 to each other is selected such that the passing height h ( figure 2 ) Is at least 30% to 60% of the blade depth t.

[0026] An inlet opening 40 is formed between two adjacent stator connecting pieces. Preferably, all the inlet openings 40 are located in a common inlet plane, which is directly connected to the last rotor element 18 in the conveying direction 26. In the circumferential direction, the entrance opening 40 has an opening width of 10% to 15% of the entire circumference.