Linear driving mechanism

A linear drive mechanism comprising:

• a housing;
• a front cover and a rear cover respectively fixed at opposite ends of the housing;
• a stator inside the housing;
• a hollow rotor;
• a first bearing sleeved in the rotor and fixed to one end of the rear cover;
• a second bearing sleeved on the rolling lead screw and fixed inside the housing;
• a rolling lead screw sleeved in the rotor, including a central screw rod set on an inner peripheral side of the rotor and passing through the front cover, a screw nut extending axially along the rotor and being fixed inside the second bearing and sleeved on the central screw rod for forming a rotational connection;
• wherein
• the rotor includes a hollow rotor body with an end away from the front cover fixed on the first bearing, and an annular protrusion protruding along an outer periphery of the rotor body close to the front cover;
• the protrusion is fixed on one end of the screw nut near the rear cover;
• the rotor rotates to drive the screw nut to rotate, thereby driving the central screw rod for performing linear telescopic movement;
• wherein a diameter of the rotor is smaller than a diameter of the screw nut;
• the rolling lead screw is a planetary rolling lead screw;
• the screw nut comprises a first nut body with a threaded structure, a first bearing stop formed on an outer circumference of the first nut body, a plurality of first mounting grooves and second mounting grooves formed by concave portions at both ends of an inner wall of the first nut body, a first gear ring fixed in the first mounting groove, a second gear ring fixed in the second mounting groove, and a plurality of annular screw columns surrounding the central screw rod;
• each end of each annular screw column is respectively set in the first gear ring and the second gear ring and forms a rotating connection;
• the first nut body is fixed in the second bearing;
• the first bearing stop abuts against the second bearing near one side of the rear cover;
• the protrusion is fixed in the first mounting groove and abuts against the first gear ring;
• the central screw rod includes a first central screw rod body set inside the rotor and provided with a threaded structure, and a first protruding end extending from one end of the first central screw rod body near the front cover;
• the first central screw rod body meshes with each of the annular screw columns, and each annular screw column meshes with the first nut body, and the first protruding end passes through the front cover.