Trim actuator

• US 6,325,331 B1
• Filed: 12/09/1999
• Issued: 12/04/2001
• Est. Priority Date: 12/11/1998
• Status: Expired due to Term

• Current Assignee: Bell Helicopter Textron Incorporated (Textron Inc)
• Original Assignee: Bell Helicopter Textron Incorporated (Textron Inc)
• Inventors: McKeown, William L.
• Primary Examiner(s): Jordan, Charles T.
• Assistant Examiner(s): Best, Christian M.
• Application Number:
  US09/457,821
• Time in Patent Office: 726 Days
• Field of Search: 170/135.72, 310/162, 310/89, 318/254, 318/562, 244/76.A, 244/221, 244/224, 244/220
• US Class Current: 244/76.00A
• CPC Class Codes: B64C 13/08 Trimming zero positions
• CPC Class Codes: B64C 13/16 actuated automatically, e.g. responsive to gust detectors
• CPC Class Codes: B64C 13/34 using toothed gearing

Abstract

A trim actuator for actuating mechanical controls in an aircraft flight control system in response to signals from a pilot having a stepper motor, a gear train member coupled to the stepper motor, an output member coupled to the gear train member. The trim actuator has a locked mode in which the mechanical controls are held in a fixed position relative to the aircraft, and a non-interference mode in which the mechanical controls are free to be moved by the pilot without interference from the aircraft flight control system. The non-interference mode and the locked mode are both achieved by the stepper motor.

Claims

1. A trim actuator for actuating mechanical controls in an aircraft flight control system in response to signals from a pilot, the trim actuator comprising:

a stepper motor;

a gear train member coupled to the stepper motor;

an output member coupled to the gear train member;

wherein said trim actuator is operable in a plurality of modes by operator including;

a) a locked mode in which the mechanical controls are held in a fixed position relative to the aircraft;

b) a non-interference mode in which the mechanical controls are free to be moved by the pilot without interference from the aircraft flight control system; and

wherein the non-interference mode and the locked mode both being achieved by the stepper motor.

2. The trim actuator according to claim 1, wherein the stepper motor is an ironless-rotor, permanent-magnet stepper motor that provides damping.

3. The trim actuator according to claim 1, wherein the stepper motor is replaced by a brushless DC motor containing built-in means to commutate the power to motor windings.

4. The trim actuator according to claim 1, wherein the stepper motor is replaced by a motor with a shifting rotor.

5. The trim actuator according to claim 1, wherein the stepper motor is replaced by a motor with auxiliary holding windings.

6. The trim actuator according to claim 1, wherein the stepper motor is replaced by a motor having a uniform-ring stator or rotor.

7. The trim actuator according to claim 1, further comprising:

a torque damping member coupled to the stepper motor.

8. A method of actuating mechanical controls in an aircraft flight control system, the method comprising the steps of:

providing a stepper motor;

coupling a gear train member to the stepper motor;

coupling an output member to the gear train member;

utilizing the stepper motor to generate a locked mode in which the mechanical controls are held in a fixed position relative to the aircraft; and

utilizing the stepper motor to generate a non-interference mode in which the mechanical controls are free to be moved by the pilot without interference from the aircraft flight control system.

9. The method according to claim 8, wherein the stepper motor is an ironless-rotor, permanent-magnet stepper motor that provides damping.

10. The method according to claim 8, wherein the stepper motor is replaced by a brushless DC motor containing built-in means to commutate the power to motor windings.

11. The method according to claim 8, wherein the stepper motor is replaced by a motor with a shifting rotor.

12. The method according to claim 8, wherein the stepper motor is replaced by a motor with auxiliary holding windings.

13. The method according to claim 8, wherein the stepper motor is replaced by a motor having a uniform-ring stator or rotor.

14. The method according to claim 8, further comprising the step of:

providing a torque damping member coupled to the stepper motor.