US 12,206,305 B2
Electrical machines for aircraft power and propulsion systems
Ellis F H Chong, Derby (GB); Andreas Reeh, Nuremberg (DE); Johannes Gabriel Bauer, Neuried (DE); and Anton Rudenko, Ottobrunn (DE)
Assigned to Rolls-Royce Deutschland Ltd & Co KG, Blankenfelde-Mahlow (DE)
Filed by Rolls-Royce Deutschland Ltd & Co KG, Blankenfelde-Mahlow (DE)
Filed on Oct. 20, 2023, as Appl. No. 18/491,033.
Application 18/491,033 is a continuation of application No. 18/201,619, filed on May 24, 2023, granted, now 11,824,410.
Claims priority of application No. 2300383 (GB), filed on Jan. 11, 2023.
Prior Publication US 2024/0250594 A1, Jul. 25, 2024
Int. Cl. H02K 21/24 (2006.01); B64C 29/00 (2006.01); B64D 27/24 (2024.01); H02K 1/14 (2006.01); H02K 3/24 (2006.01)
CPC H02K 21/24 (2013.01) [B64C 29/0033 (2013.01); B64D 27/24 (2013.01); H02K 1/145 (2013.01); H02K 3/24 (2013.01); H02K 2201/12 (2013.01); H02K 2213/03 (2013.01)] 20 Claims
OG exemplary drawing
 
1. A transverse flux electrical machine for coupling to a rotating shaft of a propulsor of an aircraft, the transverse flux electrical machine comprising:
a rotor having a plurality of circumferentially distributed permanent magnets that form a number, NP, of rotor poles, wherein the rotor poles have a pole pitch angle, Pθ, equal to 2π divided by the number of rotor poles, NP;
a stator having a plurality of current-carrying coils configured to interact with the rotor poles of the rotor to produce a torque; and
an air gap separating the rotor from the stator by an air gap distance, GAir,
wherein a machine parameter, custom character, defined as:

OG Complex Work Unit Math
is less than 100 micro radian-meters,
wherein an active parts torque density, ρact, of the transverse flux electrical machine is defined as:

OG Complex Work Unit Math
wherein τpeak is a peak rated torque of the transverse flux electrical machine and mact is an active parts mass of the transverse flux electrical machine,
wherein the active parts mass is a cumulated mass of components of the transverse flux electrical machine that contribute to producing the torque, and
wherein ρact is in a range of 50 to 165 Nmkg−1.