Linear drive unit

• US 6,327,925 B1
• Filed: 11/25/1998
• Issued: 12/11/2001
• Est. Priority Date: 11/28/1997
• Status: Expired due to Fees

• Current Assignee: Siemens AG
• Original Assignee: Deutsches Zentrum Fã¼R Luft- Und Raumfahrt E.V.
• Inventors: Willberg, Bertram, Gombert, Bernd
• Primary Examiner(s): Olszewski, Robert P.
• Assistant Examiner(s): Chin, Paul T.
• Application Number:
  US09/199,548
• Time in Patent Office: 1,112 Days
• Field of Search: 187/250, 187/267, 187/268, 74/89, 74/891.5, 74/99.A, 741/10
• US Class Current: 74/110
• CPC Class Codes: F16H 27/02 with at least one reciprocating or oscillating transmission member F16H27/04 takes precedence
• CPC Class Codes: Y10T 74/18984 Inclined ramp
• CPC Class Codes: Y10T 74/18992 Reciprocating to reciprocating

Abstract

A linear drive unit has a threaded rod, and in combing engagement with same a threaded nut (2), from the outer circumference of which a number of equally spaced cogs (3) project in a radial direction. Furthermore, connecting links (4, 5), which extend parallel to the axis of the threaded rod inside a housing, are driven via hydraulically or pneumatically actuated pistons, causing the connecting links (4, 5) to move in an axial direction. During this oscillating movement the connecting links act upon cogs (3) that project from the threaded nut (2). The force exerted via the cogs (3) located on the outer circumference of the threaded nut (2) causes the threaded nut (2) to be put into an incremental rotation, which, in turn, causes an incremental linear shifting of the threaded rod (1).

Claims

1. A linear drive unit, comprising:

a housing (14);

a screw drive having an axis and being disposed generally within the housing, the screw drive comprising a threaded rod (1) in meshing engagement with a threaded nut (2);

a cog ring forming a unit with the threaded nut (2) or rod (1), centered on the axis and comprising a number of projecting cogs equally spaced along a circumference thereof, rotation of the cog ring about the axis causing a relative axial translation between the rod and the nut; and

a connecting link (4, 5) extending axially parallel to the axis of the threaded rod, the connecting link being movable to and fro in an axial direction, to rotate the cog ring in increments;

wherein an incremental axial shifting of the threaded rod (1) or nut (2) relative to the housing occurs.

2. The linear drive unit according to claim 1, comprising a pair of connecting links.

3. The linear drive unit according to claim 2, wherein each of the connecting links comprises serrations (44) preventing an unintentional rotation of the cog wheel.

4. The linear drive unit according to claim 1, comprising hydraulically actuated pistons (6, 7) driving the connecting links (4, 5).

5. The linear drive unit according to claim 1, comprising a pneumatically actuated piston driving the connecting link (4, 5).

6. The linear drive unit according to claim 1, comprising a cam disk (93, 97) driving the connecting link (4, 5).

7. The linear drive unit according to claim 1, comprising a crank mechanisms (101, 105) driving the connecting link (4, 5).

8. The linear drive unit according to claim 1, comprises a ballscrew driving the connecting link.

9. The linear drive unit according to claim 1, comprising a planetary rolling contact gear driving the connecting link.

10. The linear drive unit according to claim 1, wherein the screw drive is manufactured entirely from materials that do not interfere with electrical or magnetic fields.

11. The linear drive unit according to claim 1, comprising a lifting magnet (111, 115) driving the connecting link (4,5).