# US 11,994,200 B1 · Concentric electric-motor driveshaft system and method

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- Number: US 11,994,200 B1
- Document ID: US11994200B1
- Status: Granted
- Kind: B1
- Application number: 17/984,610
- Filed: 2022-11-10
- Published: 2024-05-16
- Granted: 2024-05-28
- Earliest claimed: 2022-11-10
- Assignees: Textron Innovations Inc.
- Applicants: Textron Innovations Inc.
- Inventors: Grant Michael Beall
- Web page: https://patentgrep.com/patent/US11994200B1

## CPC

- F16H 57/0025: {with gearing elements rigidly connected to a shaft, e.g. securing gears or pulleys by specially adapted splines, keys or methods}
- H02K 7/10: Structural association with clutches, brakes, gears, pulleys or mechanical starters
- B64D 27/30: Aircraft characterised by electric power plants
- B64D 35/021: for electric power plants
- B64D 35/08: characterised by the transmission being driven by a plurality of power plants (for hybrid-electric power plants B64D35/022)
- B64U 50/19: using electrically powered motors
- F16D 3/06: specially adapted to allow axial displacement
- F16D 9/08: over a single area encircling the axis of rotation, e.g. shear necks on shafts (F16D9/10 takes precedence)
- F16D 41/07: between two cylindrical surfaces
- H02K 7/003: {Couplings; Details of shafts (means for mounting rotors on shafts H02K1/28)}
- H02K 7/116: with gears
- H02K 16/00: Machines with more than one rotor or stator {(machines for transmitting mechanical power from a driving shaft to a driven shaft and comprising structurally interrelated motor and generator parts H02K51/00; permanent magnet machines with multiple rotors or stators relatively rotated for vectorially combining the excitation fields or the armature voltages H02K21/029)}
- B64C 27/00: Rotorcraft; Rotors peculiar thereto
- F16H: GEARING
- H02K: DYNAMO-ELECTRIC MACHINES (dynamo-electric relays H01H53/00; conversion of DC or AC input power into surge output power {H03K3/53})
- B64D: EQUIPMENT FOR FITTING IN OR TO AIRCRAFT; FLIGHT SUITS; PARACHUTES; ARRANGEMENT OR MOUNTING OF POWER PLANTS OR PROPULSION TRANSMISSIONS IN AIRCRAFT
- B64U: UNMANNED AERIAL VEHICLES [UAV]; EQUIPMENT THEREFOR
- F16D: COUPLINGS FOR TRANSMITTING ROTATION; CLUTCHES; BRAKES
- B64C: AEROPLANES; HELICOPTERS

## Abstract

An electric-motor system includes a forward electric-motor assembly, a rear electric-motor assembly arranged in series relative to the forward electric-motor assembly, a forward electric-motor driveshaft splined to the forward electric-motor assembly and comprising a forward electric-motor drive-shaft shear section, and a rear electric-motor driveshaft splined to the rear electric-motor assembly and comprising a rear electric-motor drive-shaft shear section, at least a portion of the rear electric-motor driveshaft arranged concentrically within the forward electric-motor driveshaft. The forward electric-motor driveshaft and the rear electric-motor driveshaft rotate about a common axis.

## Claims

### Claim 1

An electric-motor system comprising:
a forward electric-motor assembly;
a rear electric-motor assembly arranged in series relative to the forward electric-motor assembly;
a forward electric-motor driveshaft splined to the forward electric-motor assembly and comprising a forward electric-motor drive-shaft shear section; and
a rear electric-motor driveshaft splined to the rear electric-motor assembly and comprising a rear electric-motor drive-shaft shear section, at least a portion of the rear electric-motor driveshaft arranged concentrically within the forward electric-motor driveshaft;
wherein the forward electric-motor driveshaft and the rear electric-motor driveshaft rotate about a common axis;
wherein the forward electric-motor driveshaft comprises an inner-diameter spline splined to an outer-diameter spline of an input gear; and
wherein the rear electric-motor driveshaft comprises an outer-diameter spline splined to an inner-diameter spline of the input gear.

### Claim 2 (depends on 1)

The electric-motor system of claim 1, wherein the forward electric-motor driveshaft and the rear electric-motor driveshaft are each interoperably coupled via the input gear to a gearbox to be driven by the forward electric-motor assembly and the rear electric-motor assembly.

### Claim 3 (depends on 2)

The electric-motor system of claim 2, wherein the forward electric-motor drive-shaft shear section shears responsive to an impulse load greater than a maximal expected operational load on the forward electric-motor driveshaft.

### Claim 4 (depends on 3)

The electric-motor system of claim 3, wherein the rear electric-motor drive-shaft shear section shears responsive to an impulse load greater than a maximal expected operational load on the rear electric-motor driveshaft.

### Claim 5 (depends on 4)

The electric-motor system of claim 4, wherein, responsive to shearing of the rear electric-motor drive-shaft shear section, the rear electric-motor assembly is rotationally disconnected from the input gear.

### Claim 6 (depends on 3)

The electric-motor system of claim 3, wherein, responsive to shearing of the forward electric-motor drive-shaft shear section, the forward electric-motor assembly is rotationally disconnected from the input gear.

### Claim 7 (depends on 1)

The electric-motor system of claim 1, wherein:
the forward electric-motor driveshaft is splined to the forward electric-motor assembly via a forward electric-motor outer-diameter spline; and
the rear electric-motor driveshaft is splined to the rear electric-motor assembly via a rear electric-motor outer-diameter spline.

### Claim 8 (depends on 1)

The electric-motor system of claim 1, wherein the forward electric-motor drive-shaft shear section and the rear electric-motor drive-shaft shear section are concave in shape.

### Claim 9

An electric-motor system comprising:
a forward electric-motor assembly;
a rear electric-motor assembly arranged in series relative to the forward electric-motor assembly;
a forward electric-motor driveshaft splined to the forward electric-motor assembly and comprising a forward electric-motor drive-shaft shear section;
a rear electric-motor driveshaft splined to the rear electric-motor assembly and comprising a rear electric-motor drive-shaft shear section, at least a portion of the rear electric-motor driveshaft arranged concentrically within the forward electric-motor driveshaft;
wherein the forward electric-motor driveshaft and the rear electric-motor driveshaft rotate about a common axis; and
an input gear splined to the forward electric-motor driveshaft and to the rear electric-motor driveshaft.

### Claim 10 (depends on 9)

The electric-motor system of claim 9, wherein:
the forward electric-motor driveshaft is splined to an outer-diameter spline of the input gear, and
the rear electric-motor driveshaft is splined to an inner-diameter spline of the input gear.

### Claim 11 (depends on 10)

The electric-motor system of claim 10, comprising a gearbox splined to the input gear and that receives torque from the forward electric-motor assembly and the rear electric-motor assembly.