Abstract:
The present invention discloses a turbo molecular pump with improved blade structures. The turbo molecular pump comprises a rotor and a stator, wherein the rotor includes five rotor blade assemblies and the stator includes five stator blade assemblies, and wherein the blade number and the blade angle of each rotor blade assembly and stator blade assembly are adjusted to optimization, so as to enhance the pumping speed and the stability of the turbo molecular pump as well as to reduce the difficulty for manufacturing the turbo molecular pump.

Description:
BACKGROUND OF THE INVENTION 
       [0001]    1. Field of the Invention 
         [0002]    The present invention relates to a turbo molecular pump with improved blade structures, and more particularly to a turbo molecular pump having rotor blades and stator blades which are optimally adjusted for several parameters. 
         [0003]    2. Description of the Prior Art 
         [0004]    In recent years, semiconductor industries are developed rapidly, so that the requirement of the related apparatuses in front-end stage of the semiconductor is largely increased, and wherein a turbo molecular pump, the major device in the high vacuum system, has a great demand. 
         [0005]    The turbo molecular pump is originated in 1912 and improved from a molecular drag pump invented by a German, Gaede. Referring to  FIG. 1 , which is a cross-sectional view of a conventional turbo molecular pump. The conventional turbo molecular pump A includes a rotor A 1  and a stator A 2 , wherein the rotor A 1  includes a rotor shaft A 10  and a plurality of rotor blades A 11 , and the stator A 2  includes a plurality of stator blades A 21 . The rotor blades A 11  and the stator blades A 21  are disposed in a staggered manner layer by layer. 
         [0006]    Referring to  FIG. 2 , which is a schematic diagram of an action principle of a turbo molecular pump. After a gas molecule B 5  entering the turbo molecular pump B 1 , the gas molecule B 5  get into next level of stator blade B 3  driven by a rotor blade B 2 , as indicated by the dotted line. Following, the gas molecule B 5  rams the stator blade B 3  and turns its forward direction, and then gets into the next level of rotor blade B 4 . Therefore, the action principle of the turbo molecular pump B 1  is to make the gas molecules originally having chaotic movement in the system move forward an exit by inclined blades with high-speed rotation, and to elevate a compression ratio by the staggered arrangement of multi-level rotor blades and stator blades. Owing to the turbo molecular pump has the property of high vacuum, high exhaust efficiency and no oil pollution, the turbo molecular pump is widely used on various researches and applications. 
         [0007]    Owing to the turbo molecular pump is popularly applied in researches and industries with high precision, thus the pumping efficiency is very important. However, although the turbo molecular pump has been improved by many researchers constantly, the pumping efficiency and the stability of the turbo molecular pump are not excellent enough yet. 
         [0008]    In view of this, it is necessary to provide an improved turbo molecular pump, which can increase the pumping speed and stability by the optimized design of the structure. 
       SUMMARY OF THE INVENTION 
       [0009]    In view of the above shortcomings of the prior art, the inventor of the present invention resorted to past experience, imagination, and creativity, performed experiments and researches repeatedly, and eventually devised the present invention, a turbo molecular pump with improved blade structures. 
         [0010]    The major objective of the present invention is to provide the turbo molecular pump with improved blade structures, wherein several parameters of rotor blades and stator blades of the turbo molecular pump are adjusted to optimal conditions, so as to significantly elevate the pumping speed and stability of the turbo molecular pump. 
         [0011]    According to the above objective, the present invention provides the turbo molecular pump with improved blade structures comprising: a rotor comprising: a center shaft; a first layered rotor blade assembly being disposed on the center shaft, wherein the blade number of the first layered rotor blade assembly is 16˜17 pieces, and the blade angle of the first layered rotor blade assembly being 37˜45 degree; a second layered rotor blade assembly being disposed on the center shaft and contiguous to the first layered rotor blade assembly, wherein the blade number of the second layered rotor blade assembly is 32˜33 pieces, and the blade angle of the second layered rotor blade assembly being 45˜50 degree; a third layered rotor blade assembly being disposed on the center shaft, and the third layered rotor blade assembly and the first layered rotor blade assembly being disposed on opposite side of the second layered rotor blade assembly, wherein the blade number of the third layered rotor blade assembly is 30˜31 pieces, and the blade angle of the third layered rotor blade assembly being 30˜40 degree; a fourth layered rotor blade assembly being disposed on the center shaft, and the fourth layered rotor blade assembly and the second layered rotor blade assembly being disposed on opposite side of the third layered rotor blade assembly, wherein the blade number of the fourth layered rotor blade assembly is 28˜29 pieces, and the blade angle of the fourth layered rotor blade assembly being 25˜30 degree; a fifth layered rotor blade assembly being disposed on the center shaft, and the fifth layered rotor blade assembly and the third layered rotor blade assembly being disposed on opposite side of the fourth layered rotor blade assembly, wherein the blade number of the fifth layered rotor blade assembly is 26˜27 pieces, and the blade angle of the fifth layered rotor blade assembly being 15˜22 degree; and a stator comprising: a first layered stator blade assembly being disposed between the first layered rotor blade assembly and the second layered rotor blade assembly, wherein the blade number of the first layered stator blade assembly is 50˜52 pieces, and the blade angle of the first layered stator blade assembly being 45˜70 degree; a second layered stator blade assembly being disposed between the second layered rotor blade assembly and the third layered rotor blade assembly, wherein the blade number of the second layered stator blade assembly is 50˜52 pieces, and the blade angle of the second layered stator blade assembly being 48˜70 degree; a third layered stator blade assembly being disposed between the third layered rotor blade assembly and the fourth layered rotor blade assembly, wherein the blade number of the third layered stator blade assembly is 50˜52 pieces, and the blade angle of the third layered stator blade assembly being 40˜70 degree; a fourth layered stator blade assembly being disposed between the fourth layered rotor blade assembly and the fifth layered rotor blade assembly, wherein the blade number of the fourth layered stator blade assembly is 34˜36 pieces, and the blade angle of the fourth layered stator blade assembly being 28˜40 degree; and a fifth layered stator blade assembly being disposed on opposite side of the fifth layered rotor blade assembly relative to the fourth layered stator blade assembly, wherein the blade number of the fifth layered stator blade assembly is 34˜36 pieces, and the blade angle of the fifth layered stator blade assembly being 22˜40 degree. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0012]    For a complete understanding of the aspects, structures and techniques of the invention, reference should be made to the following detailed description and accompanying drawings wherein: 
           [0013]      FIG. 1  is a cross-sectional view of a conventional turbo molecular pump; 
           [0014]      FIG. 2  is a schematic diagram of an action principle of a turbo molecular pump; 
           [0015]      FIG. 3  is a perspective view of a rotor of a turbo molecular pump of the present invention; and 
           [0016]      FIG. 4  is a perspective view of a stator of the turbo molecular pump of the present invention. 
       
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
       [0017]    To achieve the foregoing objectives and effects, the inventors adjust several parameters of rotor blades and stator blades of a turbo molecular pump to optimal conditions, thus achieving a turbo molecular pump with improved blade structures. 
         [0018]    The turbo molecular pump of the present invention is composed of a rotor and a stator, wherein the rotor and the stator are primarily made of pure aluminum or aluminum alloy, which has advantages of lightweight, corrosion prevention, manufacturing easily, and moderate strength and toughness. The rotor and the stator also can be made of copper or gold, however, the copper and the gold have higher cost, softer texture, higher weight, and lower strength and toughness than aluminum. Additionally, steel, iron, cast metal, and stainless steel also can be the material of the rotor and the stator, but these materials have disadvantages of rigid texture, heavy weight, susceptible to corrosion, and difficult to be manufactured. 
         [0019]    Referring to  FIG. 3 , which is a perspective view of the rotor of the turbo molecular pump of the present invention. The rotor  100  of the present invention includes a center shaft  101 , a first layered rotor blade assembly  110 , a second layered rotor blade assembly  120 , a third layered rotor blade assembly  130 , a fourth layered rotor blade assembly  140 , and a fifth layered rotor blade assembly  150 . 
         [0020]    The first layered rotor blade assembly  110  is disposed on the center shaft  101 . The blade number of the first layered rotor blade assembly  110  is 16˜17 pieces, and the blade angle of the first layered rotor blade assembly  110  is 37˜45 degree. 
         [0021]    The second layered rotor blade assembly  120  is disposed on the center shaft  101  and contiguous to the first layered rotor blade assembly  110 . The blade number of the second layered rotor blade assembly  120  is 32˜33 pieces, and the blade angle of the second layered rotor blade assembly  120  is 45˜50 degree. 
         [0022]    The third layered rotor blade assembly  130  is disposed on the center shaft  101 , and the third layered rotor blade assembly  130  and the first layered rotor blade assembly  110  are disposed on opposite side of the second layered rotor blade assembly  120 . The blade number of the third layered rotor blade assembly  130  is 30˜31 pieces, and the blade angle of the third layered rotor blade assembly  130  is 30˜40 degree. 
         [0023]    The fourth layered rotor blade assembly  140  is disposed on the center shaft  101 , and the fourth layered rotor blade assembly  140  and the second layered rotor blade assembly  120  are disposed on opposite side of the third layered rotor blade assembly  130 . The blade number of the fourth layered rotor blade assembly  140  is 28˜29 pieces, and the blade angle of the fourth layered rotor blade assembly  140  is 25˜30 degree. 
         [0024]    The fifth layered rotor blade assembly  150  is disposed on the center shaft  101 , and the fifth layered rotor blade assembly  150  and the third layered rotor blade assembly  130  are disposed on opposite side of the fourth layered rotor blade assembly  140 . The blade number of the fifth layered rotor blade assembly  150  is 26˜27 pieces, and the blade angle of the fifth layered rotor blade assembly  150  is 15˜22 degree. 
         [0025]    Referring to  FIG. 4 , which is a perspective view of the stator of the turbo molecular pump of the present invention. The stator  200  of the present invention includes a first layered stator blade assembly  210 , a second layered stator blade assembly  220 , a third layered stator blade assembly  230 , a fourth layered stator blade assembly  240 , and a fifth layered stator blade assembly  250 . 
         [0026]    The first layered stator blade assembly  210  is disposed between the first layered rotor blade assembly  110  and the second layered rotor blade assembly  120 . The blade number of the first layered stator blade assembly  210  is 50˜52 pieces, and the blade angle of the first layered stator blade assembly  210  is 45˜70 degree. 
         [0027]    The second layered stator blade assembly  220  is disposed between the second layered rotor blade assembly  120  and the third layered rotor blade assembly  130 . The blade number of the second layered stator blade assembly  220  is 50˜52 pieces, and the blade angle of the second layered stator blade assembly  220  is 48˜70 degree. 
         [0028]    The third layered stator blade assembly  230  is disposed between the third layered rotor blade assembly  130  and the fourth layered rotor blade assembly  140 . The blade number of the third layered stator blade assembly  230  is 50˜52 pieces, and the blade angle of the third layered stator blade assembly  230  is 40˜70 degree. 
         [0029]    The fourth layered stator blade assembly  240  is disposed between the fourth layered rotor blade assembly  140  and the fifth layered rotor blade assembly  150 . The blade number of the fourth layered stator blade assembly  240  is 34˜36 pieces, and the blade angle of the fourth layered stator blade assembly  240  is 28˜40 degree. 
         [0030]    The fifth layered stator blade assembly  250  is disposed on opposite side of the fifth layered rotor blade assembly  150  relative to the fourth layered stator blade assembly  240 . The blade number of the fifth layered stator blade assembly  250  is 34˜36 pieces, and the blade angle of the fifth layered stator blade assembly  250  is 22˜40 degree. 
         [0031]    Furthermore, the first layered stator blade assembly  210 , the second layered stator blade assembly  220 , the third layered stator blade assembly  230 , the fourth layered stator blade assembly  240 , and the fifth layered stator blade assembly  250  further include a stator shroud  211 ,  221 ,  231 ,  241 , and  251  respectively, each stator shroud  211 ,  221 ,  231 ,  241 , and  251  can fasten the blades of each layered stator blade assembly  210 ,  220 ,  230 ,  240 , and  250 , and also can used for combining the stator blade assemblies  210 ,  220 ,  230 ,  240 , and  250  to each other. 
         [0032]    In the present invention, the rotor blades and the stator blades of the turbo molecular pump are divided into five layers, which have functions of increasing the compression ratio and the compression efficiency, so as to achieve the effect of ultrahigh vacuum, and then enhance the accuracy and the cleanliness of a vacuum coating equipment for a semiconductor process. 
         [0033]    By the detailed description of the overall structure and technical content of the present invention, the following advantages of the present invention can be derived: 
         [0034]    The present invention adjusts several parameters of the rotor blades and the stator blades to optimal condition, so as to significantly enhance the pumping speed and the stability of the turbo molecular pump. 
         [0035]    The blade number of each layered rotor blade assembly of the present invention is less than the blade number of the conventional turbo molecular pump, so that the manufacture and the fabrication of the turbo molecular pump are much easier, and the manufacturing cost can be reduced. 
         [0036]    It should be understood that the embodiments of the present invention described herein are merely illustrative of the technical concepts and features of the present invention and are not meant to limit the scope of the invention. Those skilled in the art, after reading the present disclosure, will know how to practice the invention. Various variations or modifications can be made without departing from the spirit of the invention. All such equivalent variations and modifications are intended to be included within the scope of the invention. 
         [0037]    As a result of continued thinking about the invention and modifications, the inventors finally work out the designs of the present invention that has many advantages as described above. The present invention meets the requirements for an invention patent, and the application for a patent is duly filed accordingly. It is expected that the invention could be examined at an early date and granted so as to protect the rights of the inventors.