Modular linear electric motor with limited stator excitation zone and stator gap compensation

• US 7,019,421 B1
• Filed: 02/20/2004
• Issued: 03/28/2006
• Est. Priority Date: 02/20/2004
• Status: Active Grant

• Current Assignee: Curtiss-Wright Electro-Mechanical Corporation (Curtiss-Wright Corporation)
• Original Assignee: Curtiss-Wright Electro-Mechanical Corporation (Curtiss-Wright Corporation)
• Inventors: Lemak, Thomas A., Hall, David J., Hillenbrand, Regis J.
• Primary Examiner(s): Schuberg, Darren
• Assistant Examiner(s): JONES, JUDSON
• Application Number:
  US10/783,794
• Time in Patent Office: 767 Days
• Field of Search: 187/250, 187/251, 187/289, 310 12- 14
• US Class Current: 310/12.11
• CPC Class Codes: B66B 11/0407 actuated by an electrical linear motor in the counterweight B66B17/12
• CPC Class Codes: B66B 13/143 electrical
• CPC Class Codes: H02K 41/03 Synchronous motors; Motors moving step by step; Reluctance motors H02K41/035 takes precedence
• CPC Class Codes: H02P 25/06 Linear motors

Abstract

A linear motor system including compartmentalized stator sections provides an interchangeable and serviceable alternative to other linear motors. The stator sections may be individually-energized so that power is only sent to stator sections adjacent to the thrust plate or rotor of the linear motor. A sufficiently long thrust plate is used to cover any gaps in the linear stator, and additional compensation stator sections are used to provide additional motor force to the thrust plate adjacent to these gap sections. If utilized onboard a ship, additional compensation stator sections may be incorporated into the face of deck hatches. The linear motor system can also be used to counteract gravitational effects in a large hanging door system implementation.

Claims

1. A linear motor elevator system, comprising:

at least one linear stator comprised of individually-energized stator sections, said linear stator including a gap;

at least one thrust plate oriented adjacent to said stator;

an elevator platform attached to said thrust plate; and

at least one compensation stator section located adjacent to said gap in said linear stator and in parallel with said linear stator, wherein said thrust plate is longer than said gap.

2. The motor system of claim 1, wherein said individually-energized stator sections are grouped into replaceable stator modules.

3. The motor system of claim 1, further comprising:

a controller that determines which of said stator sections is to be energized at any instant.

4. The motor system of claim 1, further comprising:

a second linear stator in parallel with said first linear stator and also being comprised of individually-energized stator sections.

5. The motor system of claim 4, further comprising:

a second thrust plate connected to said platform and adjacent to said second linear stator.

6. The motor system of claim 1, further comprising:

a hatch compensation stator oriented in parallel with said linear stator and disposed in said gap.

7. The motor system of claim 3, further comprising:

a position sensor attached to said platform and in communicative contact with said controller.

8. The motor system of claim 1, wherein said thrust plate includes permanent magnets.

9. The motor system of claim 1, wherein said thrust plate includes a slotted iron core and copper or aluminum bars.

10. The motor system of claim 1, wherein said thrust plate includes a smooth copper or aluminum plate backed by iron.

11. A linear motor drive system for moving large doors, comprising:

at least one linear stator comprised of individually-energized stator sections, said linear stator including a gap;

at least one thrust plate adjacent to said stator, said stator and thrust plate oriented so that an attraction force between the stator and the thrust plate is vertically upward;

a door panel attached on the bottom of said thrust plate; and

at least one compensation stator section located adjacent to said gap in said linear stator and in parallel with said linear stator, wherein said thrust plate is longer than said gap.

12. The motor system of claim 11, wherein said individually-energized stator sections are grouped into replaceable stator modules.

13. The motor system of claim 11, further comprising:

a controller that determines which of said stator sections is to be energized at any instant.

14. The motor system of claim 11, further comprising:

a second linear stator in parallel with said first linear stator and also being comprised of individually-energized stator sections.

15. The motor system of claim 14, further comprising:

a second thrust plate connected to said door and adjacent to said second linear stator.

16. The motor system of claim 13, further comprising:

a position sensor attached to said door and in communicative contact with said controller.

17. The motor system of claim 11, wherein said thrust plate includes permanent magnets.

18. The motor system of claim 11, wherein said thrust plate includes a slotted iron core and copper or aluminum bars.

19. The motor system of claim 11, wherein said thrust plate includes a smooth copper or aluminum plate backed by iron.

20. The motor system of claim 11, wherein said door has rollers attached on a side of said door opposite said thrust plate.