Tuned rat driveshaft

Patent metadata

Field	Value
Publication number	US-2017191559-A1
Application number	US-201614989561-A
Country	US
Kind code	A1
Filing date	Jan 6, 2016
Priority date	Jan 6, 2016
Publication date	Jul 6, 2017
Grant date	—

Abstract

A driveshaft for an aircraft ram air turbine, the driveshaft including a cylindrical body having an outer surface, an inner surface, a longitudinal axis, a first end section, a second end section opposite the first end section, and an elongated intermediate section connecting the first end section and the second end section. The outer surfaces of the elongated intermediate section includes at least three separate grooves initiating at a location proximate to the first end section and extending parallel to the longitudinal axis across the outer surface to a location proximate to the second end section, the grooves being separated equidistantly around a circumference of the outer surface. The grooves provide a high lateral bending stiffness and low torsional stiffness such that a drivetrain operates at a frequency below an operating range frequency and the driveshaft at a critical speed above an operating speed.

First claim

What is claimed is:

1 . A driveshaft for an aircraft ram air turbine, the driveshaft comprising:
a cylindrical body having an outer surface, an inner surface, a longitudinal axis, a first end section, a second end section opposite the first end section, and an elongated intermediate section connecting the first end section and the second end section, wherein the outer surfaces of the elongated intermediate section includes at least three separate grooves initiating at a location proximate to the first end section and extending parallel to the longitudinal axis across the outer surface to a location proximate to the second end section, the grooves being separated equidistantly around a circumference of the outer surface, wherein the grooves provide a high lateral bending stiffness and low torsional stiffness such that a drivetrain operates at a frequency below an operating range frequency and the driveshaft at a critical speed above an operating speed.

2 . The driveshaft of claim 1 , wherein:
the grooves are configured in at least one of a rectangular shape, a round shape, a dovetail shape, a splined shape, a T shape, and an L shape.

3 . The driveshaft of claim 2 , further includes:
a plurality of splines located around the outer surface of the second end section.

4 . The driveshaft of claim 3 , further includes:
a plurality of splines located around the outer surface of the first end section.

5 . The driveshaft of claim 4 , wherein:
the outer surface of the elongated intermediate section is tapered towards the first end section and tapered towards the second end section.

6 . The driveshaft of claim 3 , wherein:
the outer surface of the elongated intermediate section is tapered towards the second end section.

7 . The driveshaft of claim 6 , further including:
a pinion gear affixed to the first end section.

8 . The driveshaft of claim 7 , further including:
a bearing affixed to the pinion gear.

9 . A ram air turbine comprising:
a turbine assembly mechanically connected to a power conversion device through a driveshaft, the driveshaft comprising:
a cylindrical body having an outer surface, an inner surface, a longitudinal axis, a first end section, a second end section opposite the first end section, and an elongated intermediate section connecting the first end section and the second end section,
wherein the outer surface of the elongated intermediate section includes at least three separate grooves initiating at a location proximate to the first end section and extending parallel to the longitudinal axis across the outer surface to a location proximate to the second end section, the grooves being separated equidistantly around a circumference of the outer surface,
wherein the grooves provide a high lateral bending stiffness and low torsional stiffness such that a drivetrain operates at a frequency below an operating range frequency and the driveshaft at a critical speed above an operating speed.

10 . The ram air turbine of claim 9 , wherein:
the grooves of the driveshaft are configured in at least one of a rectangular shape, a round shape, a dovetail shape, a splined shape, a T shape, and an L shape.

11 . The ram air turbine of claim 10 , wherein the driveshaft further includes:
a plurality of splines located around the outer surface of the second end section.

12 . The ram air turbine of claim 11 , wherein the driveshaft further includes:
a plurality of splines located around the outer surface of the first end section.

13 . The ram air turbine of claim 12 , wherein:
the outer surface of the elongated intermediate section of the driveshaft is tapered towards the first end section and tapered towards the second end section.

14 . The ram air turbine of claim 11 , wherein:
the outer surface of the elongated intermediate section of the driveshaft is tapered towards the second end section.

15 . The ram air turbine of claim 14 , further including:
a pinion gear affixed to the first end section of the driveshaft.

16 . The ram air turbine of claim 15 , further including:
a bearing affixed to the pinion gear.

Assignees

• Hamilton Sundstrand Corp

Inventors

• Russ David Everett

Classifications

• F16D1/06

  for attachment of a member on a shaft or on a shaft-end (attachment of marine propellers on shafts B63H23/34) · CPC title

• F16C3/02 Primary

  Shafts; Axles · CPC title

• B64D41/007

  Ram air turbines · CPC title

• F16H57/0025 Primary

  with gearing elements rigidly connected to a shaft, e.g. securing gears or pulleys by specially adapted splines, keys or methods · CPC title

• F02K7/10

  characterised by having ram-action compression, i.e. aero-thermo-dynamic-ducts or ram-jet engines · CPC title