Patent Number: 042382882
Section: claims

1. A drive for driving a control element of a nuclear reactor having a coolant contained therein, said drive comprising: an electromotor having a housing and having a supply voltage applied thereto;  said electromotor including a stator accommodated in said housing, insulated from the coolant of said nuclear reactor, and producing an electromagnetic field as said supply voltage is applied to said electromotor, said stator including an active part of given length;  said electromotor further including a rotor also accommodated in said housing so that said stator encompasses said rotor with a certain clearance between them, said rotor comprising two lengthwise parts, a first part and a second part, the total length of said two parts being equal to the given length of the active part of said stator;  securing means for securing said rotor in said housing;  the first part of said rotor comprising a solid cylinder-shaped member secured in said housing by said securing means;  a drive screw having a shaft extending inside said solid cylinder-shaped member, said drive screw being coupled to said control element;  the second part of said rotor comprising at least three double-arm rocking levers, each having a first arm, a second arm and a pivot axle coupled to and intermediate said first arm and said second arm;  said first arm, said second arm and said pivot axle being parallel to said shaft of said drive screw and secured in said housing by said securing means, the first arm of each said lever acting as a pole of said rotor; and  rollers, one for each double-arm rocking lever, each said roller having an axle of rotation and mounted on corresponding said second arm of said each double-arm rocking lever so that said axle of rotation is parallel to said shaft of said drive screw, each said roller comprising detachable roller nut means rotatably mounted with axis parallel to said shaft of said drive screw for interacting with said drive screw under the action of said electromagnetic field of said stator.