Self-generating device and mechanical system using the same

A mechanical system equipped with a self-generating device, the mechanical system comprising:

• a power generating part generating power,
• a main shaft connected to the power generating part, receiving the power generated from the power generated part, and rotating with a rotational force using the power;
• an operating part receiving the rotational force from the main shaft and performing a mechanical motion that the mechanical system aims at, using the rotational force, and
• a self-generating part mounted on the main shaft and generating induced electricity using the rotational force, wherein the self-generating part including:
• the main shaft rotating according to the rotational force;
• a rotor assembly combined with the main shaft and rotating along with the main shaft according to the rotational force, and
• a stator assembly surrounding the rotor assembly and staying stationary relative to the rotation of the rotor assembly, wherein the at least one of the rotor and the stator generates a magnetic field and the other one or both have wire windings in which change of the magnetic field induces electricity;
• wherein the main shaft includes at least one external screw portion positioned on at least one side of a set of the rotor assembly and the stator assembly, and the self-generating device further comprises a bearing mounted on the screw portion of the main shaft,
• wherein the external screw portion includes a raised helical thread, and a width of the raised helical thread becomes wider as the raised helical thread is closer to the set of the rotor assembly and the stator assembly,
• wherein an internal side of a bore of the bearing has an internal screw portion that is engaged with the external screw portion of the main shaft,
• wherein the bearing includes:
• an inner bearing having a first race, a second race surrounding the first race, and inner balls positioned between the first and the second race, and
• an outer bearing having the second race, a third race surrounding the third race, and outer balls positioned between the second and the third race.