Brushing retention of threaded fastener

Patent metadata

Field	Value
Publication number	US-10247218-B2
Application number	US-201614991087-A
Country	US
Kind code	B2
Filing date	Jan 8, 2016
Priority date	Mar 10, 2015
Publication date	Apr 2, 2019
Grant date	Apr 2, 2019

Abstract

A fastener assembly includes a first component having a back face and a first mating face opposing the back face, and a second component having a front face and a second mating face opposing the front face. The first component and the second component arranged such that the first mating face is closest to the second mating face. A bushing is installed through the first component, an outer surface of the bushing having frictional engagement with the first component to retain the bushing thereat. A threaded fastener extends through the bushing and the second component, and transmits a load into the bushing. A nut is secured to the fastener at the second component to retain the second component at the first component and which induces the load into the fastener. The frictional engagement between the bushing and the first component is configured to resist the load applied to the fastener.

First claim

What is claimed is:

1. A fastener assembly comprising:
a first component defining a rotor blade having a back face and a first mating face opposing the back face, and an opening including an inner circumferential surface extending from the back face to the first mating face;
a second component defining a rotor hub having a front face and a second mating face opposing the front face, the rotor blade and the rotor hub arranged such that the first mating face is closest to the second mating face;
a bushing installed through the opening of the rotor blade, an outer circumferential surface of the bushing having a direct frictional engagement with the inner circumferential surface of the opening in the rotor blade to retain the bushing thereat;
a threaded fastener extending through the bushing and through the rotor hub, the threaded fastener transmitting a tensile load into the bushing; and
a nut secured to the threaded fastener at the rotor hub to retain the rotor hub at the rotor blade and which induces the load into the threaded fastener,
wherein the frictional engagement between the bushing and the rotor blade resists the tensile load applied to the threaded fastener.

2. The fastener assembly according to claim 1 , wherein the bushing includes a conical bushing surface complimentary to a conical fastener surface at a head of the threaded fastener, to react to the tensile load applied to the threaded fastener.

3. The fastener assembly according to claim 1 , wherein the bushing is brought into frictional engagement with the rotor blade via a cold expansion process.

4. The fastener assembly according to claim 1 , wherein the outer surface of the bushing is absent friction reducing or anti-fretting coatings.

5. The fastener assembly according to claim 1 , wherein the bushing further includes a flange disposed at the back face.

6. The fastener assembly according to claim 1 , further comprising a washer disposed at the rotor hub between the nut and the rotor hub.

7. The fastener assembly according to claim 1 , wherein the tensile load is up to a maximum tensile strength of the threaded fastener.

8. A method of securing a first component defining a rotor blade having a first mating surface to a second component defining a rotor hub having a second mating surface, the method comprising:
inserting a bushing into a first opening including an inner circumferential surface extending from a back face to the first mating surface in the rotor blade;
engaging an outer surface of the bushing into direct frictional contact with the inner circumferential surface of the first opening in the rotor blade;
inserting a threaded fastener through the bushing and through the rotor hub such that a portion of the threaded fastener is capable of transmitting a tensile load into the bushing; and
installing a nut onto the threaded fastener at the rotor hub so as to fasten the rotor blade and the rotor hub and to induce the tensile load into the threaded fastener, wherein the frictional contact is sufficient to resist tensile loads applied to the bushing via the threaded fastener.

9. The method according to claim 8 , further comprising reacting tensile loads applied to the threaded fastener via a conical bushing surface complimentary to a conical fastener surface at a head of the threaded fastener.

10. The method according to claim 9 , wherein the conical bushing surface is formed in the bushing prior to inserting of the bushing into the first opening.

11. The method according to claim 8 , further comprising bringing the bushing into frictional engagement with the rotor blade via a cold expansion process.

12. The method according to claim 8 , wherein the bushing further includes a flange disposed at the back face.

13. The method according to claim 8 , further comprising installing a washer at the rotor hub between the nut and the rotor hub.

14. The method according to claim 8 , wherein the tensile load is up to a maximum tensile strength of the threaded fastener.

Assignees

• Sikorsky Aircraft Corp

Inventors

• Kirchen Adrial
• Bourque Richard T
• Mailhot Kristin Elizabeth

Classifications

• F16B19/02 Primary

  Bolts or sleeves for positioning of machine parts, e.g. notched taper pins, fitting pins, sleeves, eccentric positioning rings · CPC title

• F16B5/02

  by means of fastening members using screw-thread ({F16B5/0004 takes precedence}; construction of screw-threaded connections F16B25/00 - F16B39/00) · CPC title

• F16B2043/008

  with a cavity for receiving the bolt head in order to make a flush surface · CPC title

• B64C27/48

  Root attachment to rotor head · CPC title