Leadscrew drive with annular-shell leadscrew
View Patent ↗A leadscrew drive has a leadscrew follower, and a leadscrew. The leadscrew is formed as an elongated annular leadscrew shell having a thread-form outer surface. The leadscrew may be fabricated by depositing a leadscrew-shell material, such as nickel, onto a mandrel having a thread-form outer surface, so that the thread-form outer surface of the mandrel is replicated in an outer surface of the leadscrew-shell material. The mandrel may be removed, to leave a hollow leadscrew shell, or left in place.
1. A leadscrew drive comprising:
a leadscrew follower; and
an elongated flexible tubular leadscrew shaft comprising:
an internal core support comprising a helical wire; and
a leadscrew shell supported on the internal core support and including an outer surface having a helical thread-form,
wherein the leadscrew shaft engages the leadscrew follower and extends through the leadscrew follower to an end of the leadscrew shaft that is rotationally driveable by a motor and spaced apart from the leadscrew follower along a longitudinal axis of the leadscrew shaft, and
wherein a thickness of the leadscrew shell including the helical thread-form is substantially constant along a length of the leadscrew shell having the helical thread-form.
2. The leadscrew drive of claim 1 , wherein:
the leadscrew shell is formed to have a ratio of annular thickness to an outer diameter of the leadscrew of not more than 0.01.
3. The leadscrew drive of claim 1 , wherein:
the leadscrew shell is formed to have a ratio of annular thickness to an outer diameter of the leadscrew within the range of 0.0004 to 0.01.
4. The leadscrew drive of claim 3 , wherein:
the leadscrew shell is of a nickel-alloy metal formed of an electroless deposited nickel-based matrix, the electroless deposited nickel-based matrix having polytetrafluoroethylene particles.
5. The leadscrew drive of claim 4 , wherein:
the amount of polytetrafluoroethylene particles is about 20% by volume.
6. The leadscrew drive of claim 3 , wherein:
the leadscrew shell is formed of a high density, low porosity, smooth material with an even thickness.
7. The leadscrew drive of claim 1 , wherein:
the leadscrew shell is formed of a nickel-based metal.
8. The leadscrew drive of claim 7 , wherein:
the leadscrew shell is formed of a nickel-alloy metal.
9. The leadscrew drive of claim 1 , wherein:
the leadscrew shell is formed of an electroless deposited nickel-based matrix.
10. The leadscrew drive of claim 9 , wherein:
the leadscrew shell is formed of an electroless deposited nickel-based matrix with polytetrafluoroethylene particles.
11. The leadscrew drive of claim 10 , wherein:
the amount of polytetrafluoroethylene particles is about 20% by volume.
12. The leadscrew drive of claim 1 , wherein:
the leadscrew shell is formed of a high density, low porosity material.
13. The leadscrew drive of claim 12 , wherein:
the leadscrew shell is of even thickness and formed of a smooth material.