Stator element for a holweck pump stage, vacuum pump having a holweck pump stage and method of manufacturing a stator element for a holweck pump stage

Abstract

A stator element for a Holweck pump stage has a base shape of substantially cylinder jacket shape or a kit of parts for a stator element for a Holweck pump stage which has a base shape of a substantially cylinder jacket shape, wherein the stator element or the kit of parts comprises a plurality of stator parts which are separate from one another, which are assembled to form the stator element or can be assembled to form the stator element. A vacuum pump having a Holweck pump stage as well as to a method of manufacturing a stator element for a Holweck pump stage or of manufacturing a kit of parts for a stator element for a Holweck pump stage are also disclosed.

Claims

1. A stator element for a Holweck pump stage which has a base shape of substantially cylinder jacket shape, wherein the stator element comprises a plurality of mutually separate stator parts (12, 12′, 12″) which are assembled to form the stator element or which can be assembled to form the stator element, and wherein each of the plurality of separate stator parts (12, 12′, 12″) only covers a part region of a peripheral angle of the stator element defined relative to a longitudinal axis (24) of the stator element, and each of the separate stator parts (12, 12′, 12″) has a plurality of web sections (14, 14′, 14″), wherein a surface of the stator element provided with pump activity is divided by two mutually adjacent stator parts (12, 12′ and 12″) parallel to the longitudinal axis (24) of the stator element and/or obliquely to the longitudinal axis of the stator element, the two mutually adjacent stator parts (12, 12′, 12″) have mutually disposed and facing each other separating surfaces (18, 20, 22) extending through the surface of the stator element.

2. The stator element in accordance with claim 1, wherein at an outer jacket surface and an inner jacket surface of each stator part forms a surface provided with pump activity, and the plurality of web sections is provided on both the outer and inner jacket surfaces, extend helically in an axial direction and have grooves (16) arranged between the web sections (14, 14′, 14″), the grooves extending helically in an axial direction, and wherein the stator parts (12, 12′, 12″) each forming one of a region of the surface provided with pump activity and the surfaces provided with pump activity.

3. The stator element in accordance with claim 1, wherein each stator part (12, 12′, 12″) covers a range of less than or equal to 180° of the peripheral angle of the stator element defined relative to a longitudinal axis (24) of the stator element.

4. The stator element in accordance with claim 1, wherein at least one section of a surface of the stator element provided with pump activity is divided by two mutually adjacent stator parts (12, 12′, 12″) along one of a groove (16) and a web (14, 14′, 14″) of the surface provided with pump activity.

5. The stator element in accordance with claim 1, wherein each stator part (12, 12′, 12″) is configured such that a plurality of stator parts (12, 12′, 12″) identical to the stator part (12, 12′, 12″) can be assembled to form the stator element.

6. The stator element in accordance with claim 1, wherein the stator element is assembled from a kit of parts which comprises the plurality of mutually separate stator parts (12, 12′, 12″) which can be assembled to form the stator element.

7. A method of manufacturing a stator element for a Holweck pump stage which has a base shape of substantially cylinder jacket shape, the method comprising the steps of manufacturing a plurality of separate stator parts (12, 12′, 12″) which form together a stator element, with each stator part having a plurality of web sections (14, 14′, 14″), and assembling the stator parts (12, 12′, 12″) from a kit of stator parts to form the stator element, so that each of the plurality of stator parts only covers a part region of a peripheral angle of the stator element defined relative to a longitudinal axis of the stator element, wherein assembling of the stator element is so carried out that a surface of the stator element provided with pump activity is divided by two mutually adjacent stator parts (12, 12′ and 12″) parallel to the longitudinal axis (24) of the stator element and/or obliquely to the longitudinal axis of the stator element, with mutually disposed and facing surfaces (18, 20, 22) of the two mutually adjacent stator parts (12, 12′, 12″) extending through the surface of the stator element.

8. The method in accordance with claim 7, further comprising the step of first manufacturing a base body for the stator part (12, 12′, 12″), and subsequently post-machining the base body to form the stator part (12, 12′, 12″).

9. The method in accordance with claim 8, wherein the step of manufacturing the base body is carried out by a primary molding process.

10. The method in accordance with claim 8, wherein the step of post-machining the base body is carried out by a shaping process.

11. The method in accordance with claim 7, wherein the step of manufacturing the plurality of stator parts (12, 12′, 12″) comprises the step of manufacturing each stator part (12, 12′, 12′) by molding.

12. The method in accordance with claim 7, wherein the each stator part (12, 12′, 12″) is manufactured from a plastic at least in part.

13. The method in accordance with claim 7, wherein the step of manufacturing the each stator part (12, 12′, 12″) comprises the step of manufacturing the stator part (12, 12′, 12″) by blow molding or by three-dimensional printing.

14. A method according to claim 7, comprising the step of manufacturing at least one member selected from the group comprising the stator element with the plurality of stator parts (12, 12′, 12″), a base body for the stator element and a base body for each stator part (12, 12′, 12″) by one of the following processes selected from the group comprising molding manufacturing from a plastic at least in part by blow molding and by three-dimensional printing so that each of the plurality of stator parts only covers a part region of a peripheral angle of the stator element defined relative to a longitudinal axis (24) of the stator element.

15. A vacuum pump, having at least one Holweck pump stage which comprises at least one stator element, the stator element having a base shape of substantially cylinder jacket shape, and with the stator element comprising a plurality of mutually separate stator parts (12, 12′, 12″) with each of the plurality of stator parts having a plurality of web sections (14, 14′ 14″) which are assembled to form the stator element or which can be assembled to form the stator element so that each of the plurality of the stator parts only covers a part region of a peripheral angle of the stator element relative to a longitudinal axis (24) of the stator element, wherein a surface of the stator element provided with pump activity is divided by two mutually adjacent stator parts (12, 12′ and 12″) parallel to the longitudinal axis (24) of the stator element and/or obliquely to the longitudinal axis of the stator element, the two mutually adjacent stator parts (12, 12′, 12″) have mutually disposed and facing each other separating surfaces (18, 20, 22) extending through the surface of the stator element.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) The invention will be described in the following by way of example with reference to advantageous embodiments and to the enclosed drawings. There are shown:

(2) FIG. 1 a perspective view of a stator element in accordance with an embodiment of the invention;

(3) FIG. 2 a perspective view of a stator element in accordance with an embodiment of the invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

(4) FIG. 1 shows a stator element in accordance with an embodiment of the invention in the assembled state. The stator element has a base shape of substantially cylinder jacket shape and comprises three separate stator parts 12, 12′, 12″ which divide the stator element into three angular sections. The separating surfaces between the individual stator parts 12, 12′, 12″ are marked by the reference numerals 18, 20, 22 in FIG. 1 and extend substantially in parallel to the longitudinal axis 24 of the stator element so that each stator part 12, 12′, 12″ forms a cylinder jacket segment having a substantially rectangular contour shape viewed from its flat side.

(5) Each stator part 12, 12′, 12″ comprises a respective plurality of web sections 14, 14′, 14″ both at its outer side and at its inner side, said web sections together forming webs which extend helically in the direction of the longitudinal axis 24, which are arranged at the inner jacket surface and at the outer jacket surface of the stator element and between which grooves 16 are formed which respectively extend helically in the direction of the longitudinal axis 24. The webs and grooves 16 in this respect each form a Holweck thread at the inner jacket surface and at the outer jacket surface of the stator element which is suitable to form a Holweck pump stage with a rotor element rotating with respect to the respective jacket surface and formed as a Holweck cylinder, with the rotor element in particular being able to have a smooth surface provided with pump activity. Due to the segmentation of the stator element, its manufacture is considerably simplified since the individual stator parts 12, 12′, 12″ can be manufactured, for example, by molding substantially free of undercuts and can thus be simply demolded.

(6) FIG. 2 shows a stator element in accordance with a further embodiment of the invention which substantially corresponds to the stator element shown in FIG. 1 and which only differs by the geometry of the division of the stator element into stator parts 12, 12′, 12″. The stator element is divided by the three stator parts 12, 12′, 12″ transversely to the longitudinal axis 24 so that each stator part 12, 12′, 12″ forms a cylinder jacket segment having a substantially diamond-shaped contour shape viewed from its flat side. The separating surfaces 18, 20, 22 each extend along the margin of a base of a groove 16 arranged at the outer jacket surface of the stator element so that the respective groove base and the respective adjacent web 14, 14′, 14″ are not interrupted by the separating surfaces 18, 20, 22 at the outer jacket surface.