Method for producing the rotor of a drag vacuum pump and a rotor produced according to this method
A one-piece rotor (1) for a drag vacuum pump (21) is designed, at least in sections, as a turbomolecular vacuum pump with rotor blades (5) and stator blades (9), The rotor (1) has a hub (2) whose peripheral surface supports the pump structures. The rotor-side pump structures include, at least in sections, blades (5), which are arranged in rows (4) and which are formed from the surface of a blank by means of metal cutting operations. The metal cutting operations include producing radial peripheral grooves (3) into which stator blade rows (9) engage when the pump is assembled. In order to simplify the machining of the rotor (1), another metal cutting operation provides the outer surface of the blank with one or more thread grooves (13).
The invention relates to a method for producing the rotor of a drag vacuum pump according to the characteristics of patent claim 1. Moreover, the invention relates to a rotor produced according to this method.
It is known to produce the individual blades of a rotor of a turbomolecular vacuum pump in that the outer surface of a cylindrical blank (preferably of aluminium) is provided with radial peripheral grooves and axially oriented grooves, such that blades are created in planes perpendicular with respect to the axis of rotation. In order to attain blades exhibiting an effective pumping action, each of the multitude of blades needs to be subsequently set. Generally the blades shall have differing angles of attack/setting angles depending on their distance with respect to the inlet. The known production method does not allow for further variations of the blade profiles.
Moreover, it is known to prepare the blades by milling these from the surface of a blank, such that subsequent setting will no longer be required. This manufacturing procedure involves long processing times, particularly since it is desirable that the blades of different blade rows exhibit differing blade profiles and/or angles of attack.
It is the task of the present invention to reduce the previously required processing times and thus the costs for manufacturing rotors for drag vacuum pumps.
In accordance with the invention this task is solved through the characterising features of the patent claims. The invention allows the formation of rows of blades exhibiting differing angles of attack or blade profiles in a simple manner through metal cutting operations. This can be achieved in that the pitch of the thread grooves is varied in accordance with the desired conditions. By applying the methods according to the invention the milling times may, in addition, be reduced to a minimum, respectively milling can be replaced completely by turning operations.
Further advantages and details of the present invention shall be explained with reference to the examples of embodiments depicted in the drawing figures and 1 to 91).
1) Translator's note: The German text states “8” here whereas “9” would be more in line with the drawing figures. Therefore the latter has been assumed for the translation.
Depicted are in
drawing FIGS. 1 to 4 much schematised rotors, manufactured in accordance with the present invention, whereby the rotors in accordance with the drawing
drawing FIGS. 5 to 7 rotors with greater detail, manufactured in accordance with the present invention, whereby the rotor in accordance with drawing
drawing
In all drawing figures the rotor is in each instance designated with 1 and its hub with 2. In the instance of completed rotors at least a section of the hub 2 supports rows of blades 4 separated by peripheral grooves 3, whereby the individual blades are in each instance designated as 5. In the assembled state (drawing
2) Translator's note: The German text states “(drawing
Drawing FIGS. 1 to 3 depict the manner in which a rotor 1 can be manufactured according to the present invention. Initially a, for example, cylindrical blank is provided either with thread grooves 13 (drawing
Thereafter the rotor 1 according to drawing
Drawing
Drawing
Drawing
In the embodiment according to drawing
Claims
1. A method for producing a one-piece rotor for a drag vacuum pump which is designed, at least in sections, as a turbomolecular vacuum pump with rotor blades and stator blades, the rotor having a hub whose peripheral surface supports rotor-side pump structures, which rotor-side pump structures include, at least in sections, blades which are arranged in rows and which are formed from the surface of a blank by means of metal cutting operations, the metal cutting operations comprising:
- producing radial peripheral grooves into which stator blade rows engage when the pump is assembled; and
- in another metal cutting operation, providing the outer surface of the blank with one or more thread grooves.
2. The method according to claim 1, wherein the thread grooves are produced first by milling and thereafter the peripheral grooves are produced by turning.
3. The method according to claim 1, wherein the thread grooves and the peripheral grooves are both produced by turning.
4. The method according to claim 1, wherein the peripheral grooves are produced first and thereafter the thread grooves are produced.
5. A rotor manufactured according to the method of claim 1, wherein the thread grooves and the peripheral grooves form rotor blades.
6. The rotor according to claim 5, wherein the thread grooves extend over the entire height and the peripheral grooves are section-wise.
7. The rotor according to claim 5, wherein a depth of the peripheral and thread grooves decreases at least in sections from an intake side towards a delivery side of the rotor.
8. The rotor according to claim 5, further including:
- a coaxially arranged cylinder on a delivery side.
9. A vacuum pump with the rotor produced according to the method of claim 1.
10. A method of producing a rotor for a vacuum pump comprising, in a cylinder blank in any order:
- cutting a series of spiral grooves; and
- cutting a series of peripheral grooves;
- such that a plurality of peripheral rows of blades are defined with the blades in each row angularly displaced form an adjacent row.
11. The method according to claim 10 wherein a depth of at least one of the peripheral and spiral grooves varies axially along the blank.
12. A rotor produced in accordance with the method of claim 10.
Type: Application
Filed: Feb 18, 2003
Publication Date: Oct 6, 2005
Inventors: Christian Beyer (KKoln), Heinz Englander (Linnich), Peter Laerbusch (Langerwehe), Martin Laerbusch (Langerwehe)
Application Number: 10/507,152