Synchronous Linear Motor with Non-Contacting Scanning of the Toothed Structure of the Secondary Part

• US 20080164830A1
• Filed: 04/12/2006
• Published: 07/10/2008
• Est. Priority Date: 04/15/2005
• Status: Active Grant

• Current Assignee: Siemens AG
• Original Assignee: Siemens AG
• Inventors: Jajtic, Zeljko, Knorr, Markus, Wollenberg, Johannes
• Granted Patent: US 7,679,226 B2
• Time in Patent Office: Days
• US Class Current: 318/135
• CPC Class Codes: H02K 11/00 Structural association of dynamo-electric machines with electric components or with devices for shielding, monitoring or protection casings, enclosures or supports H02K5/00
• CPC Class Codes: H02K 41/03 Synchronous motors; Motors moving step by step; Reluctance motors H02K41/035 takes precedence

Abstract

The aim of the invention is the equipping of a synchronous linear motor with a non-permanently-magnetic secondary part with a simple positional measuring system. Said aim is achieved, whereby the tooth structure of the toothed rack-shaped non-permanently-magnetic secondary part (S) varies with position in the direction of movement (B). Furthermore, the synchronous linear motor can be provided with absolute and incremental positional measuring systems, such that the coarse resolution of the absolute measuring system can be supplemented by the fine resolution of the incremental system.

Claims

1-12. -12. (canceled)

13. A synchronous linear motor, comprising:

a primary part;

a secondary part constructed in the form of a toothed rod in the absence of permanent magnets, said secondary part having a predetermined toothed structure in a movement direction of the primary part; and

a position detection device arranged directly or indirectly on the primary part for scanning the toothed structure, without making contact, in order to obtain a position signal,

wherein the toothed structure is variable as a function of position, at least in the movement direction.

14. The synchronous linear motor of claim 13, wherein the position signal is an incremental position signal.

15. The synchronous linear motor of claim 13, wherein the toothed structure is defined by slots between teeth of the tooth structure, said slots having different depths in the movement direction.

16. The synchronous linear motor of claim 13, wherein the tooth structure of the secondary part has teeth of different shape in the movement direction.

17. The synchronous linear motor of claim 13, wherein the toothed structure is position-dependent transversely with respect to the movement direction.

18. The synchronous linear motor of claim 13, wherein the toothed structure has a plurality of tracks which extend in spaced-apart relationship in the movement direction transversely to the movement direction.

19. The synchronous linear motor of claim 13, wherein the toothed structure corresponds to a position-dependent coding.

20. The synchronous linear motor of claim 19, wherein the coding defines an absolute position on the secondary part.

21. The synchronous linear motor of claim 13, wherein the secondary part is subdivided into a plurality of sections which are numbered, and further comprising a sensor attached to the primary part for detection of a numbering of the sections so that a position of the primary part is determinable from the numbering and from a position information obtained from the toothed structure.