Electromechanical drive

FIELD: electricity.

SUBSTANCE: electromechanical drive includes electric motor, stator, rollers and output stock. Stator encloses hollow rotor. Rollers are equipped with external thread and arranged in cavity of rotor in threaded sleeve in circumferential direction. Axes of rollers are parallel to rotor axis. Screw is coaxially arranged inside rotor. Screw has external thread. Thread of screw interacts with thread of rollers. Thread of rollers interacts with internal thread of sleeve. Sleeve is rigidly attached to one end of output stock. The latter is installed so that it is protected against being turned. One screw end is rigidly attached to rotor. The other end of screw is arranged in cavity of output stock.

EFFECT: higher reliability of electromechanical drive.

9 cl, 3 dwg

 

The present invention relates to an electro-mechanical linear actuators, in particular to the Electromechanical actuator, and can be used to move the shut-off valve in the control system of the turbine, which is important for the safety of nuclear power plants.

One means of ensuring the safety of nuclear power plants is the actuator shut-off valve of the turbine, allowing for a few tens of milliseconds to move the shutoff valve for a few tens of millimeters and thereby quickly change the flow rate of the working environment. In this actuator must be provided with high reliability, accuracy and speed of testing the position of the actuator drive, interacting with shut-off valve. The actuator must have a compact design.

Know the use of Electromechanical actuators for converting rotational motion into linear motion and control of machines and mechanisms connected with them. In particular, from EN 2213896 (13.04.1999) known Electromechanical actuator for valves, containing an electric motor with a hollow rotor, which houses a threaded sleeve and a screw spindle connected to the locking body. The drive is enclosed in a stationary housing. In the hollow rotor nm is the engine between the stem nut and screw posted by spindle nut, made in the form of three cylindrical threaded rollers located in the separators. Threaded sleeve and the glass is stationary in the hollow rotor, have the spline grooves, which enable their linear movement relative to each other.

Known drive is small and sufficient reliability for standard pipe fittings provided by the fact that the threaded sleeve, threaded rollers, covered it, and the screw spindle, a floating rotated around the rollers, form a roller-screw transmission, in which the load is transmitted through the threaded surface of all rollers, which ensures maximum contact area.

The main disadvantage of this drive is relatively large moment of inertia of the rotating parts of the drive. From physics it is known that the moment of inertia of the mechanical system about a fixed axis is equal to the sum of the products of the masses of all material points system on the squares of their distances to the axis. In a known drive a relatively large moment of inertia of the rotating parts due to the direct connection of the rotor with a threaded sleeve, resulting in the need for the use of glass connecting the rotor with the stem nut, and the choice of the wall thickness of the rotor and a threaded sleeve with regard to their soy is inane with a glass (for example, slotted and/or keyed), excess thickness due to their functional purpose (for example strength, magnetic saturation and so on). In other words, the direct kinematic connection of the rotor with a threaded sleeve leads to the necessity of introduction of constructive communication, implemented through additional mass enclosed between the rotor and the screw sleeve.

Thus, a large moment of inertia of the rotating parts in the known drive does not allow to provide the desired rate of mining the position of the actuator of the Electromechanical drive without high energy costs.

Furthermore, the design of known actuator does not meet the redundancy requirements of the control system of the turbine nuclear power plant to provide the required reliability and safety.

Also known in the drive there is no possibility to determine the location of its Executive body (screw spindle).

The task of the invention is to eliminate these disadvantages, in particular the provision required for the safety of nuclear power plant speed and accuracy of testing the position of the actuator drive with minimal loss of energy in the control system of the turbine unit.

This problem is solved by using linear electro is mehanicheskogo drive, containing an electric motor, the stator of which comprises a hollow rotor. In addition, the proposed actuator includes an output shaft and rollers, equipped with an external thread and placed in the cavity of the rotor into the threaded sleeve circumference so that their axes parallel to the axis of the rotor. From the known drive the proposed actuator differs in that the inside of the rotor are placed coaxially screw having external threads cooperating with the threads of the rollers, which also communicates with the internal thread of the specified sleeve rigidly connected with one end of the output rod set with a hold, turn, and with one end of the screw is rigidly connected to the rotor and the other end of the screw is placed in the cavity of the output shaft.

In the proposed drive screw, interacting through the thread rollers with a non-rotating threaded sleeve has a relatively small diameter, and the rotor is constructed as light as possible, so the rotating part of the actuator has a relatively small moment of inertia, which allows to provide the desired rate of mining the position of the actuator of the Electromechanical drive without high energy costs.

Hold the output shaft from rotation preferably is provided protivootecona device containing arm rigidly mounted on the output shaft, and wheel, two withwhich mounted on spring-loaded levers, emerging from the beam, essentially perpendicular to the longitudinal axis of the output shaft.

The rotor of the proposed Electromechanical actuator is preferably mounted in a bearing unit with prenotazione to eliminate axial play.

The interaction of the external thread of the screw with internal thread of the sleeve, through the external threads of the rollers, preferably is gapless.

In a preferred embodiment of the invention, the rollers of nine pieces placed in cages installed in the threaded sleeve and the output shaft has a smooth surface.

To repay the kinetic energy of the moving parts of the proposed Electromechanical drive for achievement of output shaft end positions of its stroke preferably limited elastic elements, such as Belleville springs or rubber buffers.

The rotor of the electric motor in the Electromechanical actuator can rotate both clockwise and against it, causing displacement of the output shaft in one direction, for example, to close the shutoff valve and in the opposite direction, respectively, to open the valve.

To ensure the reliability of the Electromechanical actuator on the rotor of the electric motor coaxially one behind the other fixed at less than the least two sets of pole magnets, covered respectively by at least two sets of pole coils of the stator, placed coaxially one behind the other. Thus, in the proposed Electromechanical actuator redundant duplication of the power of the electrical part. In addition, for the purpose of backing duplication double the electrical connectors, coil brake control, and sensor feedback.

Sensor feedback allows the required accuracy to determine the current position of the output shaft with the filing of the corresponding signal. When receiving a drive signal for changing the operating position of the shut-off valve in the engine fires one pair of stator-rotor failure which may be included in the work of another pair of the stator-rotor.

In addition, the proposed Electromechanical actuator absence of mechanical backlash, high accuracy output shaft interacting with shut-off valve, and protection of the output shaft from contamination.

The proposed Electromechanical actuator has high performance and allows for minimal energy consumption with high reliability and speed to control the position of the shutoff valve of the turbine nuclear power plant.

1 schematically shows a section of the proposed electromechani the definition of the drive.

Figure 2 schematically shows a section of the proposed Electromechanical actuator, made according to line a-a in figure 1.

Figure 3 schematically shows the construction of the spring-loaded rocker levers offer Electromechanical actuator. Depicted by the form B in figure 2.

As shown in figure 1, the Electromechanical actuator includes a motor 1, the stator 2 which covers the hollow rotor 3 and nine rollers 4, provided with an external thread and placed in the cavity of the rotor 3 in the separators 5 circumference, so that their axes parallel to the axis of the rotor 3.

The rotor 3 is rigidly connected with the screw 6, coaxially fixed within it and having external threads cooperating with the threads of the rollers 4. Thread rollers 4 also communicates with the internal thread of the sleeve 7, is placed in the cavity of the rotor 3, covering the rollers 4 and is rigidly associated with the Cup 8. The Cup 8 is placed on the end of the output rod 9, which is made preferably in one piece. Thus, the sleeve 7 is rigidly connected with the inner end of the output shaft. The outer threaded end 10 of the output 5 of the rod 9, which is the Executive body of the Electromechanical drive is connected to the locking body, in this example, with shut-off valve.

Rigid connection of the screw 6 with the rotor 3 is implemented rigid fastening one end of the screw 6 in the hub 11 of the rotor 3, which size is placed at one end of the rotor 3 and in turn, planted in paired angular contact thrust bearings bearing unit 12, providing play-free rotation of the rotor 3. The other end of the rotor 3 is planted on radial thrust bearings bearing Assembly 23. On the rotor 3 fixed two sets of pole magnets 13, placed coaxially one behind the other and covered respectively by the sets of pole coils of the stator, placed coaxially one behind the other.

Output shaft 9 is held against rotation around its longitudinal axis protivootecona device containing the rocker arm 14, which is mounted on the output shaft 9 is essentially perpendicular to it, and fixed. At the two ends of the rocker arm 14 mounted on a pair of wheels 15 (2), the axis of which is essentially perpendicular to the longitudinal axis of the output shaft 9. The axis of one wheel 15 one specified pair and the axis of one wheel 15 other specified pair, located at the opposite end of the rocker arm 14 is diametrically opposed relative to the longitudinal axis of the Rod 9, is stationary. The other two opposite wheel 15 is spring-loaded, because they are installed on the spring levers 16 (3)made with the possibility of angular displacement around its axis 17, and the axis of rotation of the spring-loaded wheel and the axis of rotation of the lever spaced a few millimeters. Eliminating coal is the first play of the rocker arm 14 is due to sample clearance between the wheels 15 and the inner surface of the longitudinal grooves of the cylinder 18 (Fig 1).

Electromechanical actuator also includes a braking device 19 having two control coils 20 and two sensors 21 feedback, mounted on the cylindrical part of the screw 6, closed on the outside by a cap 22. The housing of the Electromechanical actuator Assembly formed by the cap 22, the brake unit 19, the bearing unit 12, the engine 1, the bearing unit 23, the cylinder 18 has a mounting flange 24, which are drawn together by pins 25. The limitation of the stroke of the output rod 9 when it reaches the end position is the Belleville springs 26.

When the drive rotation of the hollow rotor 3 of the motor 1 causes the rotation of the screw 6, external thread which cooperates with a thread covering its rollers 4 and causes them to rotate around their axes. Thread rollers 4 also interacts with the internal thread of the sleeve 7. The rotation of the roller 4 causes linear movement of the sleeve 7, is rigidly connected with the output shaft 9 through the glass 8 and causing the shut-off body in translational motion. Depending on the direction of rotation of the rotor is closing or opening of the shut-off valve (not shown).

Since the diameter of the screw 6 is relatively small, and the rotor 3 is made as light as possible, the rotating part of the actuator has a small moment of inertia and provides the desired rate of mining provisions of the grant is part of the body of the Electromechanical drive without high energy costs.

1. Electromechanical actuator containing an electric motor, the stator of which comprises a hollow rotor, rollers, equipped with an external thread and placed in the cavity of the rotor into the threaded sleeve circumference so that their axes parallel to the axis of the rotor and output shaft, characterized in that the inside of the rotor are placed coaxially screw having external threads cooperating with the threads of the rollers, which also communicates with the internal thread of the specified sleeve rigidly connected with one end of the output rod set with a hold, turn, and with one end of the screw is rigidly connected to the rotor and the other end of the screw is placed in the cavity of the output shaft.

2. Electromechanical actuator according to claim 1, in which the output shaft is held from rotation around its longitudinal axis protivootecona device.

3. Electromechanical actuator according to claim 1, in which the rotor is mounted in a bearing unit with prenotazione to eliminate axial play.

4. Electromechanical actuator according to claim 1, in which the interaction of the external thread of the screw with internal thread of the sleeve, through the external threads of the rollers is gapless.

5. Electromechanical actuator according to claim 1, in which the rollers nine.

6. Electromechanical actuator according to claim 1, in which the rollers are placed in cages installed in threaded liners is E.

7. Electromechanical actuator according to claim 1, in which the output rod has a smooth surface.

8. Electromechanical actuator according to claim 1, in which the stroke of the output rod is limited by elastic elements, such as Belleville springs or rubber buffers.

9. Electromechanical actuator according to claim 1, in which the rotor coaxially to each other is fixed, at least two sets of pole magnets are covered, respectively, at least two sets of pole coils of the stator, placed coaxially one behind the other.



 

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