Linear motor

• US 4,344,022 A
• Filed: 03/24/1980
• Issued: 08/10/1982
• Est. Priority Date: 03/29/1979
• Status: Expired due to Term

• Current Assignee: Papst Licensing GmbH & Company Kg
• Original Assignee: Papst-Motoren GmbH & Company KG
• Inventors: von der Heide, Johann
• Primary Examiner(s): Dobeck, B.
• Application Number:
  US06/133,122
• Time in Patent Office: 869 Days
• Field of Search: 318/38, 318/135, 310/12, 310/13
• US Class Current: 318/38
• CPC Class Codes: H02K 41/035 DC motors; Unipolar motors

Abstract

A linear motor unit includes a stator having on outer flux-carrying structure and an inner flux-carrying structure, and an armature arranged for travel along the length of the inner flux-carrying structure. The inner flux-carrying structure comprises an elongated rod. The armature slidably positioned along these rods carries a number of coils spaced one from another in the direction of elongation of the rod and surrounding the rod. A plurality of sets of permanent magnets are concentrically positioned within the outer flux-carrying structure which is arranged in a form of two tubular elongated members. The permanent magnets in each set are radially positioned with respect to the rods and located one opposite to another. Preferably successive ones of the sets of magnets have an alternate polarity. The coils are energized periodically and in a cyclical sequence to provide a motive force for the movement of armature along the parallel rods.

Claims

1. A linear motor unit comprising a stator, an armature mounted for travel along the length of said stator, said stator including an inner flux-carrying structure and an outer flux-carrying structure, said inner flux-carrying structure having an elongated rod;

a plurality of pole areas (pitches/domains) constituted by sets of permanent magnets concentrically positioned within said outer flux-carrying structure and juxtapositioned in the direction of elongation of said rod, said permanent magnets of said sets within one pole area being radially magnetized in the same direction, the magnetic polarity of said successive pole areas alternating proceeding in the direction of armature travel from one of said pole areas to the next; and

said armature being slidably positioned on said rod and carrying a plurality of coils spaced one from another in said direction of elongation and concentrically positioned within said sets of permanent magnets, said coils being energized periodically and in a cyclical sequence to provide a motive force for the movement of said armature along said rods.

2. The linear motor of claim 1, wherein each of said sets of permanent magnets comprises a pair of cylindrical magnet half-shells.

3. The linear motor of claim 2, further including annular insulating rings mounted intermediate adjoining ones of the coils.

4. The linear motor of claim 3, wherein said armature includes two coil supports connected by a bridge.

5. The linear motor of claim 4, wherein said outer flux-carrying structure includes two elongated members of substantially cylindrical shape, each of said members being formed of two half-shells and having a slit, said slits of said two members being directed for constituting a passage to receive said bridge.

6. The linear motor of claim 1, further comprising at least one additional motor unit, said additional motor unit being connected to said linear motor unit.

7. The linear motor of claim 5, wherein said slits are coaxially aligned.

8. The linear motor of claim 7, wherein said bridge is slidably movable within a space provided between said two slits of said members of said outer flux-carrying structure.

9. A linear motor comprising at least two motor units, each of said motors units including an elongated stator, an armature mounted for travel along the length of said stator, and an articulated joint coupling for interconnecting the armatures of said motor units, said articulated joint coupling having at least one rotational degree of freedom, said stators each including inner and outer flux-carrying structures and a plurality of sets of permanent magnets concentrically positioned within said outer flux-carrying structure, said armatures being concentrically positioned within said sets of permanent magnets, said outer flux-carrying structure and the sets of permanent magnets of each motor unit defining a longitudinal slit, said articulated joint coupling being formed by a bridge comprising a web member and at least two legs, each one of said legs being fixed to the armatures of each of said motor units and extending through each one of said longitudinal slits, at least one of said legs being attached to said web member for limited relative movement thereto.

12. The linear motor of claim 9, wherein said at least one leg is provided in the central section thereof with a projection extending towards said web member, said projection carrying a pin which projects with clearance into an opening of said web member, and wherein at least one resilient member encircles said pin, said resilient member tending to center said pin relative to said opening and to space said web member from said projection.

10. A linear motor comprising at least two juxtapositioned motor units extending in laterally spaced, substantially parallel relationship, each of said motor units including a stationary elongated stator and an armature mounted for travel along the length of said stator;

and an articulated joint coupling extending between and interconnecting the armatures of said motor units for providing joint movement of said armatures, said articulated joint coupling having at least one rotational degree of freedom.

11. The linear motor of claim 10, wherein said articulated joint coupling has three rotational degrees of freedom.