Composite shaft

Patent metadata

Field	Value
Publication number	US-11466725-B2
Application number	US-202017087817-A
Country	US
Kind code	B2
Filing date	Nov 3, 2020
Priority date	Nov 6, 2019
Publication date	Oct 11, 2022
Grant date	Oct 11, 2022

Abstract

A composite shaft with an end fitting mounted on one end of said shaft and a preload structure arranged to provide a biasing force to bias the composite shaft against the end fitting. The end fitting has a first interface surface, the first interface surface being tapered at an angle to the shaft axis and the shaft has a second interface surface for engagement with the first interface surface and is tapered at an angle to the shaft axis, the second interface surface extending axially from a first end to a second end, the shaft being thicker at the second end than at the first end. The shaft has a third interface surface and the preload structure has a fourth interface surface and the contact pressure of the third interface against the fourth interface increases from the first end of the shaft to the second end of the shaft.

First claim

The invention claimed is:

1. A composite shaft with an end fitting mounted on at least one end of said shaft and a preload structure arranged to provide a biasing force to bias the composite shaft against the end fitting;
wherein the end fitting has a first interface surface, the first interface surface being tapered at an angle to the shaft axis;
wherein the shaft has a second interface surface for engagement with the first interface surface, the second interface surface being tapered at an angle to the shaft axis, the second interface surface extending axially from a first end to a second end, the shaft being thicker at the second end than at the first end;
wherein the shaft has a third interface surface;
wherein the preload structure has a fourth interface surface for engagement with the third interface surface; and
wherein at least one of the shaft and the preload structure is shaped such that the contact pressure of the third interface against the fourth interface increases from the first end of the shaft to the second end of the shaft.

2. The composite shaft as claimed in claim 1 , wherein the third interface surface is tapered.

3. The composite shaft as claimed in claim 2 , wherein the third interface surface is tapered in the opposite direction to the second interface surface.

4. The composite shaft as claimed in claim 2 , wherein the third interface surface is tapered at an angle of between 0.05 degrees and 0.8 degrees to the shaft axis.

5. The composite shaft as claimed in claim 2 , wherein the third interface surface is tapered such that diameter of the shaft along the third interface surface changes by at least 0.02 mm.

6. The composite shaft as claimed in claim 5 , wherein the third interface surface is tapered such that diameter of the shaft along the third interface surface changes by at least 0.05 mm.

7. The composite shaft as claimed in claim 6 , wherein the third interface surface is tapered such that diameter of the shaft along the third interface surface changes by at least 0.1 mm.

8. The composite shaft as claimed in claim 1 , wherein the third interface and the fourth interface are in an interference fit.

9. The composite shaft as claimed in claim 8 , wherein the interference fit is created by the preload structure having a diameter that differs from the diameter of the composite shaft by at least 80 microns.

10. The composite shaft as claimed in claim 1 , wherein the fourth interface surface is parallel to the shaft axis.

11. The composite shaft as claimed in claim 1 , wherein the preload structure has a greater radial thickness adjacent to the second end of the second interface surface than the radial thickness adjacent to the first end of the second interface surface.

12. The composite shaft as claimed in claim 11 , wherein the radial thickness of the preload structure gets progressively thicker from the first end of the second interface surface to the second end of the second interface surface.

13. The composite shaft as claimed in claim 11 , wherein the preload structure comprises a plurality of preload structures with different thicknesses.

14. The composite shaft as claimed in claim 1 , wherein the end fitting further comprises teeth on the first interface surface engaging with the composite shaft.

15. The composite shaft as claimed in claim 1 , wherein the second interface surface is located radially outwardly of the third interface surface, wherein the composite shaft is hollow and wherein the preload structure is located radially inside the composite shaft.

16. The composite shaft as claimed in claim 1 , wherein the third interface surface is located radially outwardly of the second interface surface and wherein the preload structure is provided externally around the circumference of the composite shaft.

17. The composite shaft as claimed in claim 16 , wherein the preload structure is a metallic ring.

18. A method of mounting an end fitting to a composite shaft comprising:
engaging a first interface surface of the end fitting with a second interface surface of the composite shaft, wherein the first interface surface and the second interface surface are tapered at an angle to the shaft axis such that the shaft is thicker at a second axial end of the second interface surface than at a first axial end of the second interface surface; and then
engaging a third interface surface of the shaft by a fourth interface surface of a preload structure so as to bias the first interface surface against the second interface surface;
wherein at least one of the shaft and the preload structure is shaped such that the contact pressure of the third interface against the fourth interface increases from the first axial end to the second axial end.

Assignees

• Crompton Technology Group Ltd

Inventors

• Pethick Jon
• Finney Robert Edwin
• Bernard James William

Classifications

• F16D1/092

  the pair of conical mating surfaces being provided on the coupled hub and shaft · CPC title

• F16C2229/00

  Setting preload · CPC title

• F16C3/026 Primary

  Shafts made of fibre reinforced resin · CPC title

• F16C2226/12

  by press-fit, e.g. plug-in · CPC title