Vacuum-pump rotor

Abstract

A vacuum-pump rotor, in particular a vacuum-pump rotor for a turbomolecular pump, having a hub element for connecting to a rotor shaft or for forming a rotor shaft. A plurality of rotor blades are connected to the hub element. In order to form a vacuum-pump rotor by means of which a high tip speed can be achieved, the hub element and/or the rotor blades are produced of a plurality of material layers.

Claims

1. A vacuum-pump rotor comprising: a hub element for connecting to a rotor shaft and/or for forming a rotor shaft, wherein the hub element comprises a holding element comprising fiber-reinforced material, a plurality of rotor blades radially extending from the hub element at a blade foot, and a stiffening element of a fiber-reinforced material, said stiffening element being connected to the holding element by face-to-face contact and extending into the blade foot, wherein the hub element and/or the rotor blades comprise a plurality of material layers.

2. The vacuum-pump rotor according to claim 1, wherein at least one of the material layers comprises fiber-reinforced material.

3. The vacuum-pump rotor according to claim 1, wherein the plurality of rotor blades surround the hub element, each of rotor blade of said plurality of rotor blades comprising the blade foot connected to the hub element and a blade head connected to the blade foot.

4. The vacuum-pump rotor according to claim 1, further comprising a base element comprising fiber-reinforced material said base element being directly or indirectly connected to the holding element.

5. The vacuum-pump rotor according to claim 4, wherein the base element comprises a hub member arranged in the hub element and forms the blade foot.

6. The vacuum-pump rotor according to claim 1, wherein the hub element comprises two mutually opposite holding elements having arranged between them a hub member of the base element.

7. The vacuum-pump rotor according to claim 1, wherein the stiffening element comprises, on an inner side, a fixing element extending at least partially axially and/or engaging behind the holding element.

8. The vacuum-pump rotor according to claim 1, wherein two mutually opposite stiffening elements are arranged on different sides of the base element.

9. The vacuum-pump rotor according to claim 1, wherein at least one additional blade element is provided which comprises fiber-reinforced material, said additional blade element being connected to the holding element and extending into the blade foot and into the blade head.

10. The vacuum-pump rotor according to claim 9, wherein the at least one additional blade element comprises, on an inner side, a fixing element extending at least partially axially and/or engaging behind the holding element.

11. The vacuum-pump rotor according to claim 9, wherein one of the additional blade elements comprises a radial layer of fiber-reinforced material.

12. The vacuum-pump rotor according to claim 11, wherein at least one of the additional blade elements is an inner additional blade element connected to a blade head of the base element by face-to-face contact.

13. The vacuum-pump rotor according to claim 12, wherein, in the area of the blade foot and/or the blade head, the inner additional blade element is in direct abutment on the outer additional blade element by face-to-face contact.

14. The vacuum-pump rotor according to claim 9, wherein one of the additional blade elements comprises a spread tow fabric layer.

15. The vacuum-pump rotor according to claim 14, wherein at least one of the additional blade elements is designed as an outer additional blade element connected to the inner additional blade element by face-to-face contact.

16. The vacuum-pump rotor according to claim 1, wherein the base element and at least one additional blade element has substantially the same outer contour.

17. The vacuum-pump rotor according to claim 1, wherein, in the area of the blade foot, the stiffening element is in direct face-to-face abutment on the base element and/or one of the additional blade elements.

18. The vacuum-pump rotor according to claim 1, wherein the rotor is symmetrical multi-layered relative to the base element.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) The FIGURE shows partial view of a vacuum-pump rotor in the assembled state and partially in exploded view, wherein the representation is simplified toward a more schematic rendering.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

(2) In the FIGURE, there is first shown a part of a multi-layered vacuum-pump rotor comprising material layers connected to each other. Here, a part of a hub element 10 is illustrated. Of the circular-ring-shaped hub element 10, only one circular-ring segment is shown here. The hub element 10 surrounds e.g. a rotor shaft 100 to which it is fixedly connected. Normally, a plurality of such ring-shaped hub elements are serially arranged in axial direction so that a plurality of vacuum-pump stages are assembled and form e.g. a rotor for a turbomolecular pump. Thereby, the individual hub elements can be connected to a rotor shaft 100 or themselves can form the rotor shaft 100 by being connected to each other in a corresponding manner. The hub element 10 has rotor blades 12 connected to it, each of them extending radially in the circumferential direction and being pitched, wherein, for clearer illustration, only one such rotor blade 12 is shown.

(3) For better visualization of the multi-layered configuration, the drawing further includes an exploded view of the individual layers. As a medium layer in this exploded representation, a base element 14 is shown. The configuration of the entire vacuum-pump rotor in the illustrated preferred embodiment is symmetrical to base element 14. On base element 14, a stiffening element 16 is arranged wherein, in symmetry to base element 14, a further stiffening element is arranged on the opposite side in symmetry to the illustrated stiffening element 16. This holds true, in a corresponding manner, also for the next layer which is formed by an inner additional blade element 18, wherein the second additional blade element 18 itself is provided on the opposite side in symmetry to base element 14. Correspondingly, also two outer additional blade elements 20 are provided and again are arranged in symmetry to base element 14. As further elements, two holding elements 22 are provided which again are arranged symmetrically to base element 14. Herein, the holding elements 22 are the essential elements of hub element 10.

(4) In the illustrated preferred embodiment, the base element 14 which forms the plane of symmetry has an outer contour corresponding to the outer contour of blade 12. Herein, base element 14 comprises a hub member 24 which extends into hub element 10 and respectively is arranged between the two holding elements 22 of hub element 10. In this regard, it is to be considered that the two holding elements 22 are preferably designed in ring shapes wherein, between these two ring-shaped holding elements 22, a plurality of hub members are arranged corresponding in number to the rotor blades 12. To hub member 24, a blade foot 26 is connected, preferably integrally in one piece. Said blade foot 26 represents the connection element between the hub member and a blade head 28. Herein, said blade head 28 is the essential component of rotor blade 12. The base element 14 is preferably of a one-pieced design and, according to a preferred embodiment, comprises a carbon-fiber nonwoven.

(5) The next layer is formed by the two mutually opposite stiffening elements 16. In the illustrated exemplary embodiment, the outer contour of the stiffening elements 16 corresponds to the outer contour of hub member 24 and blade foot 26. Optionally, stiffening element 16 extends only into a part of blade foot 26. The stiffening elements comprise, on an inner side, a fixing element. This fixing element extends axially outward and engages behind each of the two holding elements 22. The stiffening element 16 is preferably designed as a tangential layer and, in so far, comprises a plurality of fibers adapted to take up tangential forces in the circumferential direction. In this design, the thickness gradient in the inner area of the hub is high.

(6) The next material layer is formed by the two inner additional blade elements 18. The outer contour of the inner additional blade elements corresponds to the outer contour of the base element. The inner additional blade elements 18 again comprise a fixing element 32 engaging radially behind the holding elements 22 in correspondence to the fixing element 32. Preferably, the material fibers of the inner additional blade elements 18 are oriented radially so that these layers can be conceived of as radial layers.

(7) The next material layers are formed by the outer additional blade elements 20. The outer contour of the outer additional blade elements 20 again corresponds to the outer contour of base element 14. Further, also the outer additional blade elements 20 comprise a fixing element 34 which again engages radially behind the two holding elements 22. It is preferred that the outer additional blade elements 20 are made of a spread tow fabric.

(8) The outer material layer is formed by the two holding elements 22 wherein these do not extend into the rotor blade 12 but substantially form the hub element. Also the holding elements 22 preferably comprise material fibers, preferably plastic fibers or carbon fibers.

(9) Of essence for the disclosure is the multi-layered configuration of the vacuum-pump rotor. In this regard, the design and the respective materials of the individual layers are preferably selected under the aspect of an optimum stress-adapted choice of materials and a fiber layout adapted to the operational requirements. Thereby, vacuum-pump rotors can be produced which endure extremely high stresses and can realize a tip speed of more than 400 m/s, preferably more than 500 m/s and most preferably more than 600 m/s.