Electric machine gearbox and engine starter and power generator including gearbox

An engine starter and power generator device, comprising:

• an engine;
• an electric machine;
• and
• a gearbox arrangement comprising:
• a planetary gear arrangement configured to receive rotational input from the electric machine and from the engine and to mechanically couple the electric machine and the engine in first and second power flow directions, the planetary gear arrangement comprising a ring gear;
• a ring brake;
• a free-wheel clutch attached to a fixed structure and the ring brake, the free-wheel clutch permitting rotation of the ring brake in a first direction and preventing rotation of the ring brake in an opposite second direction;
• and
• means for moving the ring gear between a first position in which the ring gear is non-rotatably engaged with the ring brake and a second position in which the ring gear is non-rotatably engaged with a carrier, wherein the ring gear moving means comprises a shift fork;
• and
• a spring arrangement configured to urge the shift fork to the first position and means for moving the shift fork to the second position against a force of the spring arrangement,
• wherein the planetary gear arrangement comprises a planetary output gear, the planetary output gear being connected to a crankshaft of the engine via an idler gear, the spring arrangement being disposed in a shaft of the idler gear.