Composite leg for landing gear assembly

• US 8,163,368 B2
• Filed: 12/22/2008
• Issued: 04/24/2012
• Est. Priority Date: 03/31/2005
• Status: Active Grant

• Current Assignee: The Boeing Co.
• Original Assignee: The Boeing Co.
• Inventors: Kismarton, Max U.
• Primary Examiner(s): DINH, TIEN QUANG
• Application Number:
  US12/341,885
• Publication Number:
  US 20090277992A1
• Time in Patent Office: 1,219 Days
• Field of Search: 244/100.R, 244/104.LS, 244/108, 244/104.R, 244/103.R, 446/55, 428/113, 428/292.1, 428/293.1, 528/31, 528/41, 528/37
• US Class Current: 428/113
• CPC Class Codes: B64C 2025/325 specially adapted for helicopters
• CPC Class Codes: B64C 25/06 fixed
• CPC Class Codes: Y10T 428/24124 Fibers

Abstract

A composite leg for a landing gear assembly includes a composite compression cap including reinforcing fibers that provide strength in compression, and a tension cap including reinforcing fibers that provide strength in tension. The composite leg further includes a torque box including carbon reinforcing fibers for providing torsional rigidity of the leg and carrying shear flow between the caps. The carbon fibers in the torque box are oriented at +θ and −θ with respect to a longitudinal axis of the leg, where θ is between 35 and 55 degrees.

Claims

1. A composite leg for a landing gear assembly, the composite leg comprising:

a composite compression cap including reinforcing fibers that provide strength in compression;

a composite tension cap including reinforcing fibers that provide strength in tension; and

a torque box for providing torsional rigidity of the leg and carrying shear flow between the caps, the torque box including carbon fibers oriented at +θ and

−

θ

with respect to a longitudinal axis of the leg, where θ

is between 35 and 55 degrees.

2. The composite leg of claim 1, wherein plies of the carbon fibers of the torque box are interleaved with plies of the fibers in the caps.

3. The composite leg of claim 1, wherein the carbon fibers have a lower strain of compression than the fibers that provide the strength in compression, and wherein the carbon fibers have a lower strain of tension than the fibers that provide strength in tension.

4. The composite leg of claim 1, wherein the fibers providing the strength in compression include glass fibers and wherein the fibers providing strength in tension include plastic fibers.

5. The composite leg of claim 1, wherein the fibers providing strength in compression and tension both include glass fibers.

6. The composite leg of claim 1, wherein the fibers providing strength in compression and tension are oriented at +α

and −

α

with respect to the longitudinal axis, where α

is between 2 and 8 degrees for suppression or delay of ply splitting.

7. The composite leg of claim 1, wherein the compression cap is 20-40% thicker than the tension cap.

8. The composite leg of claim 1, wherein the compression cap and the tension cap have the same thickness.

9. The composite leg of claim 1, wherein the leg has holes for receiving attachment members, and wherein the leg further includes thickened pads of carbon fibers are around the holes.

10. A landing gear assembly comprising at least one composite leg of claim 1.

11. An aerospace vehicle comprising:

a fuselage; and

a landing gear assembly coupled to the fuselage, the landing gear assembly including at least one composite leg of claim 1.