Self-backdriving jackscrew apparatus

• US 6,748,816 B2
• Filed: 03/15/2002
• Issued: 06/15/2004
• Est. Priority Date: 07/23/2001
• Status: Expired due to Fees

• Current Assignee: Inteva Products LLC (Renco Group Incorporated)
• Original Assignee: Delphi Technologies, Inc. (BorgWarner Incorporated)
• Inventors: Hamminga, Jeff S., Johnson, Joseph Michael, Rogers, Lloyd Walker Jr.
• Primary Examiner(s): Bucci, David A.
• Assistant Examiner(s): McAnulty, Timothy
• Application Number:
  US10/098,959
• Publication Number:
  US 20030015047A1
• Time in Patent Office: 823 Days
• Field of Search: 74/892.3, 74/892.5, 74/893.3, 74/893.7, 185/37, 185/40.R, 185/40.B
• US Class Current: 74/89.25
• CPC Class Codes: F16H 2025/2068 Means for returning linear actuator to zero position, e.g. upon occurrence of failure by using a spring
• CPC Class Codes: F16H 25/20 Screw mechanisms with automatic reversal F16H25/12
• CPC Class Codes: Y10T 74/18576 including screw and nut
• CPC Class Codes: Y10T 74/18592 Auxiliary drive [e.g., fluid piston, etc.] for load

Abstract

A self-backdriving jackscrew apparatus including a biasing member connected to a screw portion of a jackscrew that exerts backdriving force on the screw to turn the screw in a rotational direction that returns a nut portion of the jackscrew to a home position on the screw.

Claims

1. A self-backdriving jackscrew apparatus for returning or reducing resistance to the return of a jackscrew nut to a home position on a jackscrew shaft, the apparatus comprising:

a nut supported for reciprocal translational motion and against rotational motion and having internal helical threads;

a screw having external helical threads complementing and threadedly engaging those of the nut, the screw being supported for rotation about a longitudinal screw axis to drive the nut in a driven direction along the longitudinal screw axis when the screw is rotated in a first direction about the screw axis and to backdrive the nut opposite the driven direction when the screw is rotated about the screw axis in a second rotational direction opposite the first rotational direction; and

a biasing member fixedly connected to the screw at one end and fixedly connected to a structure fixed against rotation at an opposite end, the biasing member being configured to exert backdriving force on the screw that turns the screw in the second rotational direction about the screw axis.

2. A self-backdriving jackscrew apparatus as defined in claim 1 in which the biasing member is configured to exert a backdriving force that includes a force vector component spaced from and directed perpendicular to the screw axis in the second rotational direction.

3. A self-backdriving jackscrew apparatus as defined in claim 2 in which the biasing member is configured to exert rotational backdriving force on the screw in the second rotational direction.

4. A self-backdriving jackscrew apparatus as defined in claim 3 in which the biasing member is configured to provide the same approximate torque on the jackscrew regardless of where the nut is axially positioned along the screw.

5. A self-backdriving jackscrew apparatus as defined in claim 4 in which the biasing member is a torsion spring.

6. A self-backdriving jackscrew apparatus as defined in claim 2 in which the biasing member is configured to exert a resultant backdriving force on the screw having a first component vector directed axially opposite the driven direction and a second component vector directed perpendicular to the screw axis in the second rotational direction.

7. A self-backdriving jackscrew apparatus as defined in claim 6 in which the direction of the resultant backdriving force is generally parallel to a lead angle of the helical threads of the nut and the screw.

8. A self-backdriving jackscrew apparatus as defined in claim 6 in which the biasing member is a helical torsion and compression spring.

9. A self-backdriving jackscrew apparatus as defined in claim 1 in which the apparatus includes a motor drivingly coupled to the screw and configured to rotate the screw in the first direction about the longitudinal screw axis to drive the nut in the driven direction.

10. A self-backdriving jackscrew apparatus as defined in claim 9 in which the apparatus includes a reduction gear set including a pinion gear coaxially fixed to an output shaft of the motor in a position to be driven in engagement with a spur gear coaxially fixed on the screw, the reduction gear set positioned to rotate the screw in the first direction and drive the nut in the driven direction along the screw when driven by the electric motor.

11. A self-backdriving jackscrew apparatus for returning or reducing resistance to the return of a jackscrew nut to a home position on a jackscrew shaft, the apparatus comprising:

a nut supported for reciprocal translational motion and against rotational motion and having internal helical threads;

a screw having external helical threads complementing and threadedly engaging those of the nut, the screw being supported for rotation about a longitudinal screw axis to drive the nut in a driven direction along the longitudinal screw axis when the screw is rotated in a first direction about the screw axis and to backdrive the nut opposite the driven direction when the screw is rotated about the screw axis in a second rotational direction opposite the first rotational direction; and

a biasing member fixedly connected to the screw at one end and fixedly connected to the nut at an opposite end, the biasing member being configured to exert backdriving force on the screw that turns the screw in the second rotational direction about the screw axis.

12. A method for returning a jackscrew nut to a home position on a jackscrew shaft, the method including the steps of:

providing a jackscrew apparatus including a nut supported on a screw for reciprocal translational motion, the screw being supported for rotation about a longitudinal screw axis;

fixedly connecting one end of a biasing member to the screw,

fixedly connecting a second end of the biasing member to a structure fixed against rotation, the biasing member being configured to exert backdriving force on the screw;

moving the nut along the screw in a driven direction against the backdriving force of the biasing member by rotating the screw in a first rotational direction; and

allowing the backdriving force of the biasing member to move the nut along the screw opposite the driven direction by causing the screw to rotate in a second rotational direction opposite the first rotational direction.

13. The method of claim 12 in which the steps of fixedly connecting a biasing member include:

providing a torsion spring biasing member;

fixedly connecting the one end of the spring to the screw; and

fixedly connecting the second end of the spring to the structure fixed against rotation.

14. The method of claim 12 in which the step of fixedly connecting a biasing member to the screw includes providing a combination torsion compression spring biasing member.

15. The method of claim 12 in which the step of fixedly connecting a biasing member to the screw includes providing a combination torsion compression spring having an output force vector directed parallel to a lead angle of the jackscrew when the combination spring is installed.

16. The method of claim 12 in which the steps of fixedly connecting a biasing member include:

installing a combination spring by fixedly connecting the one end of the spring to the screw and the second end of the spring to the nut.