# US 12,179,913 B2 · Ballistic resistant drive shaft

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- Number: US 12,179,913 B2
- Document ID: US12179913B2
- Status: Granted
- Kind: B2
- Application number: 16/111,352
- Filed: 2018-08-24
- Published: 2020-02-27
- Granted: 2024-12-31
- Earliest claimed: 2018-08-24
- Assignees: Hamilton Sundstrand Corporation
- Applicants: Hamilton Sundstrand Corporation
- Inventors: Mark R. Gurvich; Georgios S. Zafiris; Edward P. Marron; Brayton Reed; Joyel M. Schaefer; Michael King
- Web page: https://patentgrep.com/patent/US12179913B2

## CPC

- B64C 27/14: Direct drive between power plant and rotor hub
- B29C 70/30: Shaping by lay-up, i.e. applying fibres, tape or broadsheet on a mould, former or core; Shaping by spray-up, i.e. spraying of fibres on a mould, former or core
- B64D 35/00: Transmitting power from power plants to propellers or rotors; Arrangements of transmissions
- F16C 3/026: {Shafts made of fibre reinforced resin}
- F16C 2326/06: Drive shafts
- F16C 2326/43: Aeroplanes; Helicopters
- B64C: AEROPLANES; HELICOPTERS
- B29C: SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING (making preforms B29B11/00; making laminated products by combining previously unconnected layers which become one product whose layers will remain together B32B37/00 - B32B41/00)
- B64D: EQUIPMENT FOR FITTING IN OR TO AIRCRAFT; FLIGHT SUITS; PARACHUTES; ARRANGEMENT OR MOUNTING OF POWER PLANTS OR PROPULSION TRANSMISSIONS IN AIRCRAFT
- F16C: SHAFTS; FLEXIBLE SHAFTS; ELEMENTS OR CRANKSHAFT MECHANISMS; ROTARY BODIES OTHER THAN GEARING ELEMENTS; BEARINGS

## Abstract

A drive shaft for an aircraft according to an example of the present disclosure includes, among other things, an elongated core extending between a pair of opposed couplings, an energy absorption layer made of a composite comprising metal, the energy absorption layer disposed on the core, and a first composite ballistic layer disposed along a length of the core.

## Claims

### Claim 1

A drive shaft for an aircraft comprising:
an elongated core extending between a pair of opposed attachment portions, wherein each of the pair of opposed attachment portions is a flexible coupling having a lesser stiffness than the core, and the core is a tube including an inner diameter defining an elongated bore that extends between the pair of opposed attachment portions;
an energy absorption layer made of a composite comprising metal, the energy absorption layer disposed on the outer diameter of the core; and
a first composite ballistic layer disposed on the energy absorption layer.

### Claim 2 (depends on 1)

The drive shaft as recited in claim 1, wherein the first composite ballistic layer comprises organic fibers.

### Claim 3 (depends on 2)

The drive shaft as recited in claim 2, wherein the core comprises metal.

### Claim 4 (depends on 2)

The drive shaft as recited in claim 2, wherein the core is made of a composite material.

### Claim 5 (depends on 1)

The drive shaft as recited in claim 1, further comprising a second composite ballistic layer disposed on the inner diameter.

### Claim 6 (depends on 1)

The drive shaft as recited in claim 1, wherein each attachment portion of the pair of opposed attachment portions comprises metal.

### Claim 7 (depends on 6)

The drive shaft as recited in claim 6, wherein the energy absorption layer is arranged to establish an electrical path between the pair of attachment portions.

### Claim 8 (depends on 7)

The drive shaft as recited in claim 7, further comprising:
a second composite ballistic layer disposed on the inner diameter of the core;
wherein the core is made of a composite material; and
wherein a thickness of the core is established between the inner diameter and the outer diameter of the core, the core extends a length between the pair of opposed attachment portions, and the thickness is less than 25% of the length, and the thickness is less than 40% of the outer diameter of the core.

### Claim 9 (depends on 1)

The drive shaft as recited in claim 1, wherein each of the pair of opposed attachment portions has a lesser stiffness than the core.

### Claim 10 (depends on 1)

The drive shaft as recited in claim 1, further comprising an erosion protection layer made of a polymer, the erosion protection layer disposed on the first composite ballistic layer.

### Claim 11

A power transmission system for an aircraft comprising:
a gearbox; and
a drive shaft comprising:
a first attachment portion coupled to an engine;
a second attachment portion coupled to the gearbox;
a tubular core interconnecting the first and second attachment portions, an energy absorption layer made of a composite comprising metal, the energy absorption layer disposed on an outer diameter of the core, and a first composite ballistic layer disposed on the energy absorption layer, wherein each of the first and second attachment portions is a flexible coupling having a lesser stiffness than the tubular core, and the tubular core includes an inner diameter defining an elongated bore that extends between the first and second attachment portions.

### Claim 12 (depends on 11)

The power transmission system as recited in claim 11, further comprising a second composite ballistic layer disposed on the inner diameter of the tubular core.

### Claim 13 (depends on 11)

The power transmission system as recited in claim 11, wherein the gearbox drives one or more rotor blades.

### Claim 14 (depends on 11)

The power transmission system as recited in claim 11, wherein the gearbox is an accessory gearbox that drives one or more accessories.

### Claim 15 (depends on 14)

The power transmission system as recited in claim 14, wherein the one or more accessories include a starter, a generator, a hydraulic pump, a fuel pump and/or an environmental control system.

### Claim 16 (depends on 11)

The power transmission system as recited in claim 11, wherein the energy absorption layer is arranged to establish an electrical path between the first and second attachment portions.

### Claim 17 (depends on 16)

The power transmission system as recited in claim 16, further comprising a second composite ballistic layer disposed on the inner diameter of the tubular core.

### Claim 18

A method of fabricating a drive shaft for an aircraft comprising:
forming an energy absorption layer on an outer diameter of an elongated core, the elongated core extending between first and second attachment portions, wherein the core is a hollow tube including an inner diameter defining an elongated bore extending between the first and second attachment portions, each of the first and second attachment portions is a flexible coupling having a lesser stiffness than the core, and the energy absorption layer comprises a material selected with respect to at least one predetermined energy frequency or at least one predetermined energy level; and
forming a first composite ballistic layer on the energy absorption layer.

### Claim 19 (depends on 18)

The method as recited in claim 18, wherein the first composite ballistic layer comprises organic fibers.

### Claim 20 (depends on 18)

The method as recited in claim 18, further comprising forming a second composite ballistic layer on the inner diameter of the hollow tube.