| Drive for vacuum pump -> Monitor Keywords |
|
|
 
Drive for vacuum pumpDrive for vacuum pump description/claimsThe Patent Description & Claims data below is from USPTO Patent Application 20070286749, Drive for vacuum pump. Brief Patent Description - Full Patent Description - Patent Application Claims
A. BACKGROUND OF THE INVENTION [0001]1. Field of the Invention [0002]The present invention relates to a drive arrangement for a vacuum pump and including a motor stator, a motor rotor, and a separation member arranged between the motor stator and the motor rotor. [0003]2. Description of the Prior Art [0004]Vacuum pumps have rotating shafts the bearing of which are often lubricated by operating means such as, e.g., oil. In many vacuum pumps, this operating means is simultaneously used for sealing the working chamber, e.g., in so-called vane rotary vacuum pumps. Vacuum pumps have one or more shafts at least one of which is driven and held. [0005]Often, as a motor, an asynchronous motor is used. It is generally forbidden to locate a motor in a space filled with operating means. This requires a bulky, hermetical separation which is realized, according to the state of the art, primarily by using so-called split pot elements. The split pot element is arranged either directly in the motor gap or in a magnetic coupling and is formed of a material in which an alternating magnetic field generates no or very small eddy currents. An example of use of a split pot element in a vacuum pump is disclosed in German Publication DE-OS 10 2004 024 554. The use of a split pot element leads to increase of the motor gap which reduces the efficiency of the motor and increases power consumption. [0006]The negative influence of the split pot element on the width of the motor gap is based on a sum of separate effects. On one hand, the walls, because of manufacturing conditions, are parallel to each other only at a small degree, therefore, the wall thickness increases from the pot bottom to the attachment flange. On the other hand, a one-sided attachment by the attachment flange causes tilting of the pot element. The pot element height acts as an elongate lever, and tilting at the pot element bottom is the greatest. Therefore, the motor gap must be correspondingly large. Generally, attachment with the flange can lead in many non-magnetic materials to a danger of distortion due to stresses caused by a non-uniform application of force over the flange connection. [0007]An object of the invention is to provide a drive arrangement with a hermetically sealed separation between the rotor and stator components of an electric motor and with as small as possible motor gap. B. SUMMARY OF THE NEW INVENTION [0008]This and other objects of the present invention, which will become apparent hereinafter, are achieved by a drive arrangement which includes at least two, coaxial with each other and axially spaced from each other, guide surfaces, and in which the separation member is formed as a separation sleeve which is supported and centered between the at least two guide surfaces, with the guide surfaces contacting the outer surface of the separation sleeve. [0009]By forming the separation member as a separation sleeve which is supported and centered between at least two guide surfaces, with the guide surfaces contacting an outer surface of the separation sleeve, it is possible to form the separation member very precisely. Sleeves can be produced with high precision by grinding, turning, or drawing process which provides for a uniform wall thickness over the sleeve length. Arrangement of the sleeve within coaxial surfaces insures a precise alignment of the separation sleeve, resulting in a small motor gap. In order to prevent problems which might be caused by a thermal effect, the guide surfaces are so arranged that they contact the sleeve outer surface. This is advantageous with separation sleeves formed of a weak magnetic material, because generally the sleeve may be heated by eddy currents and, as a result, would expand greater than the components with guide surfaces. Thereby, leakage can be produced. [0010]Vice versa, even with non-magnetic materials, this arrangement is advantageous as such separation sleeve does not become heated and, therefore, does not expand. When the components with the guide surfaces slightly expands, the tension which is produced in the separation sleeve, can cause distortion. [0011]According to an advantageous embodiment of the invention, there are provided at least two components which define, together with the separation member, a chamber in which the motor stator is located. The at least two guide surfaces are provided, respectively, on the at least two components. The at least two components are aligned relative to each other by respective connection surfaces provided on the at least two components and arranged coaxially with the guide surfaces. With two components carrying the guide surfaces, a guide surface is provided at each axial end of the coils. Therefore, the separation sleeve can be held at its ends and be precisely positioned. [0012]Advantageously, the separation sleeve is formed as a glass tube. Glass has a very small heat expansion coefficient, is non-magnetic, so that no eddy current is generated, and the glass tube can be produced with precise dimensions. In addition, a type of glass having a high chemical resistance can be used. [0013]According to a further advantageous embodiment of the invention, elastomeric ring means is arranged on the outer side of the glass tube for sealing a space inside the glass tube from outside. The elastomeric ring means bears against the outer surface of the separation sleeve. Thus, even when the separation sleeve expands, sealing of the arrangement is insured. [0014]According to a still further advantageous embodiment of the invention, the at least two components form stationary, axially spaced from each other, stops for the glass tube, with an axial distance between the stops being greater than a length of the glass tube. This insures that the separation sleeve is not stressed, but rather is floatingly supported in the axial direction. [0015]With the motor rotor including permanent magnets and the motor stator including electrical coils, there is formed a motor with a high efficiency and a narrow motor gap. [0016]A vacuum pump according to the present invention includes pumping components, a shaft for supporting the pumping components, and a drive arrangement for driving the shaft. The drive arrangement includes, as discussed above, motor stator and rotor, a separation member arranged between the motor stator and the motor rotor, and at least two, coaxial with each other and axially spaced from each other, guide surfaces. The separation member is formed as a separation sleeve which is supported and centered between the at least two guide surfaces, with the guide surfaces contacting an outer surface of the separation sleeve. With such a vacuum pump, the motor rotor can be formed integrally with the shaft, so that the bearings in the motor region can be dispensed with. This reduces costs of production and sources of failure. [0017]The use of the inventive drive arrangement in vacuum pumps formed as vane rotary pumps or Roots pumps enhances the advantages the inventive drive arrangement provides. [0018]The novel features of the present invention, which are considered characteristics for the invention, are set forth in the appended claims. The invention itself, however, both as to its construction and its mode of operation, together with additional advantages and objects thereof, will be best understood from the following detailed description of preferred embodiments when read with reference to the accompanying drawings. C. BRIEF DESCRIPTION OF THE DRAWINGS [0019]The drawings show: [0020]FIG. 1 shows a cross-sectional view of a vane rotary vacuum pump; and [0021]FIG. 2 shows a cross-sectional view of a further embodiment of a vacuum pump drive arrangement according to the present invention. Continue reading about Drive for vacuum pump... Full patent description for Drive for vacuum pump Brief Patent Description - Full Patent Description - Patent Application Claims Click on the above for other options relating to this Drive for vacuum pump patent application. ###  How KEYWORD MONITOR works... a FREE service from FreshPatents1. Sign up (takes 30 seconds). 2. Fill in the keywords to be monitored. 3. Each week you receive an email with patent applications related to your keywords. Start now! - Receive info on patent apps like Drive for vacuum pump or other areas of interest. ### Previous Patent Application: Drive control device of fuel pump Next Patent Application: Sprayer for application of textured finish to surfaces Industry Class: Pumps ### FreshPatents.com Support Thank you for viewing the Drive for vacuum pump patent info. IP-related news and info Results in 0.11205 seconds Other interesting Feshpatents.com categories: Electronics: Semiconductor , Audio , Illumination , Connectors , Crypto , 174 |
 * Protect your Inventions * US Patent Office filing 
PATENT INFO |
|
