High-precision multi-rotation electric actuating mechanism

Abstract

The utility model discloses a high-precision multi-rotation electric actuating mechanism which comprises a valve rod driven and controlled by the electric actuating mechanism and a ball screw coaxially and fixedly connected with the valve rod, the ball screw is connected with an upper nut and a lower nut in series through external threads, and the periphery of the upper nut and the periphery of the lower nut are jointly sleeved with a lining. Long key grooves are axially formed in the opposite side walls of the lining, the upper nut and the lower nut and matched with flat keys, the upper end of the lining is positioned on a shaft shoulder at the end of the upper nut, the lower portion of the lower nut is sequentially matched with an adjusting gasket, an adjusting nut and a locking nut in a limiting mode with the lower end face of the lining as the limiting reference, and the adjusting gasket is tightly attached to the lower end face of the lining. The periphery of the lining is in threaded fit with a nut outer sleeve, the upper end of the nut outer sleeve is provided with an output shaft connecting shaft bayonet, the output shaft connecting shaft bayonet is in clearance fit with an output shaft of the electric actuating mechanism, and axial power transmission is formed. The transmission device is high in transmission precision and small in transmission torque, and reduces the load of the motor.

Description

Technical Field

[0001] The utility model relates to a high-precision multi-rotation electric actuator, belonging to the technical field of valve regulation and control. Background Art

[0002] Currently, commonly used control valves use a trapezoidal thread screw that rotates with a nut. The nut's rotation drives the screw's linear motion. The trapezoidal thread screw has high torque during the adjustment process, and the nut can rotate forward and reverse at any time. This can cause thread clearance adjustment lag during reverse rotation, affecting adjustment accuracy. Summary of the Invention

[0003] In view of the above-mentioned deficiencies in the prior art, the present invention proposes a high-precision multi-rotation electric actuator, which ensures that the lead screw moves smoothly and without gaps when moving in the forward and reverse directions of the linear stroke, solves the motion gap and improves the adjustment accuracy.

[0004] In order to achieve the above-mentioned purpose, the technical solution of the present utility model is as follows: a high-precision multi-turn electric actuator, comprising a valve stem positioned on a regulating valve and regulating the flow between a medium inlet and a medium outlet by controlling the lifting and lowering of a valve core, the valve stem being driven to lift and lower by an electric actuator, and also comprising a ball screw coaxially connected to the valve stem, the ball screw external thread being serially connected with an upper nut and a lower nut, the upper nut and the lower nut both being matched with the ball screw through a plurality of balls, and the upper nut and the lower nut both being provided with a reverse ball return device;

[0005] The outer peripheries of the upper nut and the lower nut are jointly sleeved with a bushing, and the opposite side walls of the bushing, the upper nut, and the lower nut are axially provided with a long keyway, and the long keyway is matched with a flat key, the upper end of the bushing is positioned on the shaft shoulder of the upper nut end, and the lower part of the lower nut is sequentially limited with an adjusting washer, an adjusting nut, and a locking nut with the lower end surface of the bushing as a limit reference, and the adjusting washer is tightly attached to the lower end surface of the bushing;

[0006] The outer peripheral thread of the bushing is matched with a nut sleeve, and the upper end of the nut sleeve is provided with an output shaft connecting shaft bayonet, which is clearance-matched with the output shaft of the electric actuator to form axial power transmission.

[0007] Furthermore, the nut sleeve is a cylindrical structure with an open lower end, the output shaft connecting shaft bayonet is integrally formed at the sealed end of the cylindrical structure, and the axial center line of the output shaft connecting shaft bayonet coincides with the axial center line of the ball screw; the side wall of the nut sleeve is provided with a locking pin, which is positioned on the outer peripheral wall of the bushing.

[0008] Furthermore, an adjusting base is positioned on the regulating valve, the valve stem passes through the adjusting base, and the dynamic seal is axially slidably arranged on the adjusting base.

[0009] Furthermore, a mounting bracket is fixed to the upper end of the adjustment base, and vertical slide rails are provided on two opposite inner sides of the mounting bracket. A connecting sleeve is slidably provided on the vertical slide rail, and the connecting sleeve coaxially connects the valve stem and the ball screw through threads and / or positioning keys.

[0010] Furthermore, a fixed ruler arranged parallel to the valve stem is positioned on the inner side of the mounting bracket through a mounting plate, a movable ruler is slidably arranged on the fixed ruler, and the movable ruler is synchronously connected to the connecting sleeve through an adjustable screw.

[0011] Furthermore, the movable ruler is provided with a high-precision display.

[0012] Furthermore, a bearing seat is fixedly connected to the mounting bracket, and the nut sleeve is positioned in the bearing seat through at least two sets of bearings; the electric actuator is fixedly connected to the bearing seat through an actuator flange.

[0013] The beneficial effects of the utility model are as follows: a motor, ball screw and double nut structural design are adopted, and the clearance of the double nuts is adjusted by using adjusting washers, adjusting nuts and locking nuts, thereby eliminating the axial clearance between the ball screw and the double nuts when moving in the forward and reverse directions; and the balls move in the screw and nut grooves, with high transmission accuracy and low transmission torque, thereby reducing the load on the motor. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 It is a structural diagram of the utility model;

[0015] Figure 2 yes Figure 1 Schematic diagram of the structure between the ball screw and the double nut. DETAILED DESCRIPTION

[0016] The present invention will be described in further detail below with reference to specific embodiments and accompanying drawings.

[0017] A kind of Figure 1-2 The high-precision multi-turn electric actuator shown includes a valve stem 16 positioned on a regulating valve 31 and regulating the flow between a medium inlet 34 and a medium outlet 35 by controlling the elevation of a valve core 32. The valve stem 16 is driven to rise and fall by the electric actuator 1 and also includes a ball screw 15 coaxially connected to the valve stem 16. The ball screw 15 is externally threaded with an upper nut 6 and a lower nut 11. The upper nut 6 and the lower nut 11 are both engaged with the ball screw 15 via a plurality of balls 18. The upper nut 6 and the lower nut 11 are both provided with a reverse ball return device 33.

[0018] The outer periphery of the upper nut 6 and the lower nut 11 are jointly sleeved with a bushing 9. The opposite side walls of the bushing 9, the upper nut 6, and the lower nut 11 are axially provided with a long keyway, and the long keyway is matched with a flat key 10. The upper end of the bushing 9 is positioned on the shaft shoulder at the end of the upper nut 6. The lower part of the lower nut 11 is limited in sequence with an adjusting washer 12, an adjusting nut 13 and a locking nut 14 with the lower end surface of the bushing 9 as the limit reference. The adjusting washer 12 is tightly attached to the lower end surface of the bushing 9.

[0019] The outer thread of the bushing 9 is matched with the nut sleeve 4, and the upper end of the nut sleeve 4 is provided with an output shaft connecting shaft bayonet 36. The output shaft connecting shaft bayonet 36 is clearance-matched with the output shaft 2 of the electric actuator 1 to form axial power transmission.

[0020] The reverse ball return device 33 ensures that the balls 18 can move freely in the screw groove when the ball screw 15 moves in the forward and reverse directions, forming a ball circulation and avoiding jamming. A servo motor is used in the electric actuator 1 to control the forward and reverse rotation of the output shaft 2 according to the opening requirements of the regulating valve. The adjusting gasket 12, the adjusting nut 13 and the locking nut 14 on the lower nut 11 can be in various forms. The bushing 9 is used as a limit reference to press the lower nut 11 onto the upper nut 6 to eliminate the movement gap between the two. During operation, the upper nut 6 and the lower nut 11 achieve circumferential rotation consistency through the flat key 10. When adjusting the gap, the flat key 10 is used as an adjustment guide to rotate the adjusting nut 13 on the lower nut 11 to position the adjusting gasket 12 on the bushing 9. Thus, the adjusting nut 13 realizes the gap adjustment between the lower nut 11 and the upper nut 6, and then is locked by the locking nut 14.

[0021] Specific as Figure 2 The nut housing 4 is a cylindrical structure with an open lower end. The output shaft connecting shaft bayonet 36 is integrally formed at the sealed end of the cylindrical structure, and the axial centerline of the output shaft connecting shaft bayonet 36 coincides with the axial centerline of the ball screw 15. A locking pin 8 is provided on the side wall of the nut housing 4 and is positioned on the outer circumferential wall of the bushing 9. The connection between the output shaft 2 and the output shaft connecting shaft bayonet 36 can be variously configured, such as using a coupling or a connecting sleeve, as long as the output centers of the two are aligned.

[0022] An adjusting base 39 is positioned on the regulating valve 31 , the valve stem 16 passes through the adjusting base 39 , and a dynamic seal is axially slidably arranged on the adjusting base 39 . The adjusting base 39 radially positions the valve stem 16 and ensures the dynamic sealing of the axial movement of the valve stem 16 .

[0023] A mounting bracket 24 is fixed to the upper end of the adjustment base 39. Vertical rails are provided on opposite inner sides of the mounting bracket 24. A connecting sleeve 29 is slidably mounted on the vertical rails. The connecting sleeve 29 coaxially connects the valve stem 16 and the ball screw 15 via threads and / or a positioning key. The connecting sleeve 29 can be composed of two parts, which are fastened together by a hexagon socket head bolt 30. The connecting sleeve 29 covers the ends of the valve stem 16 and the ball screw 15 to form a fixed connection. This connection can be achieved, for example, by using a threaded connection, a male-female clamping connection, a positioning key, or the like.

[0024] Inside the mounting bracket 24, a fixed ruler 26 is positioned parallel to the valve stem 16 via a mounting plate 28. A movable ruler 25 is slidably mounted on the fixed ruler 26. The movable ruler 25 is synchronously connected to a connecting sleeve 29 via an adjustable screw 27. The movable ruler 25 is equipped with a high-precision display. Currently, a wide variety of movable rulers with high-precision displays are commercially available. Their operating principles and operational structures are already known in the art, so the structure and function of the movable ruler 25 will not be elaborated upon here.

[0025] Finally, the mounting bracket 24 is fixedly connected to the bearing seat 19 , and the nut sleeve 4 is positioned in the bearing seat 19 through at least two sets of bearings 21 ; the electric actuator 1 is fixedly connected to the bearing seat 19 through the actuator flange 3 .

[0026] During operation, when the upstream medium inlet 34 needs to move up and down through the valve core 32 to adjust the pressure or flow of the medium outlet 35, the electric actuator 1 rotates the servo motor forward and reverse after receiving the pressure signal or flow signal, and the speed and position of the servo motor are accurately controlled. The output shaft 2 is driven to rotate through the worm gear reduction in the motor actuator 1. The small gap between the output shaft 2 and the output shaft connecting shaft bayonet 36 drives the nut sleeve 4 to rotate. The rotation of the nut sleeve 4 simultaneously drives the upper nut 6 and the lower nut 11 to rotate synchronously. The rotation of the upper nut 6 and the lower nut 11 drives the ball screw 16 to move up and down, and the pressure or flow is adjusted by using the change in flow area. When the ball screw 16 moves up and down, the ball moves happily between the double nut and the ball screw 16. Since the adjusting nut 13, the adjusting gasket 12 and the locking nut 14 are adjusted to eliminate the moving gap, the overall movement torque is small, and the gap is zero when moving up and down.

[0027] In this case, the upper nut 6, the lower nut 11, the ball screw 16, and the ball 18 are all made of bearing steel or carburized steel and are heat-treated with a surface hardness of HRC60-62 to ensure the working strength requirements.

[0028] The above is a detailed introduction to the technical solutions provided by the embodiments of the present invention. Specific examples are used herein to illustrate the principles and implementation methods of the embodiments of the present invention. The description of the above embodiments is only applicable to help understand the principles of the embodiments of the present invention. At the same time, for those skilled in the art, according to the embodiments of the present invention, there may be changes in the specific implementation methods and application scopes. In summary, the contents of this specification should not be understood as limiting the present invention.

Claims

1. A high-precision multi-turn electric actuator, comprising a valve stem (16) positioned on a regulating valve (31) and regulating the flow between a medium inlet (34) and a medium outlet (35) by controlling the elevation of a valve core (32), wherein the valve stem (16) is driven to rise and fall by an electric actuator (1), and characterized in that: It comprises a ball screw (15) coaxially fixedly connected to the valve stem (16), the ball screw (15) is externally threaded with an upper nut (6) and a lower nut (11), the upper nut (6) and the lower nut (11) are both matched with the ball screw (15) through a plurality of balls (18), and the upper nut (6) and the lower nut (11) are both provided with a reverse ball return device (33); The outer peripheries of the upper nut (6) and the lower nut (11) are jointly sleeved with a bushing (9); the opposite side walls of the bushing (9), the upper nut (6) and the lower nut (11) are axially provided with a long keyway, and the long keyway is matched with a flat key (10); the upper end of the bushing (9) is positioned on the shaft shoulder of the end of the upper nut (6); the lower part of the lower nut (11) is limited in sequence with an adjusting washer (12), an adjusting nut (13) and a locking nut (14) with the lower end face of the bushing (9) as a limiting reference; the adjusting washer (12) is tightly attached to the lower end face of the bushing (9); The outer peripheral thread of the bushing (9) is matched with a nut sleeve (4), and the upper end of the nut sleeve (4) is provided with an output shaft connecting shaft bayonet (36). The output shaft connecting shaft bayonet (36) is clearance-matched with the output shaft (2) of the electric actuator (1) to form axial power transmission.

2. The high-precision multi-turn electric actuator according to claim 1, characterized in that: The nut housing (4) is a cylindrical structure with an open lower end, the output shaft connecting shaft bayonet (36) is integrally formed at the sealed end of the cylindrical structure, and the axial center line of the output shaft connecting shaft bayonet (36) coincides with the axial center line of the ball screw (15); a locking pin (8) is provided on the side wall of the nut housing (4), and the locking pin (8) is positioned on the outer peripheral wall of the bushing (9).

3. The high-precision multi-turn electric actuator according to claim 1, characterized in that: An adjusting base (39) is positioned on the adjusting valve (31), the valve stem (16) passes through the adjusting base (39), and a dynamic seal is axially slidably arranged on the adjusting base (39).

4. The high-precision multi-turn electric actuator according to claim 3, characterized in that: A mounting bracket (24) is fixed to the upper end of the adjustment base (39), and vertical slide rails are provided on two opposite inner sides of the mounting bracket (24). A connecting sleeve (29) is slidably provided on the vertical slide rails, and the connecting sleeve (29) coaxially connects the valve stem (16) and the ball screw (15) through a thread and / or a positioning flat key.

5. The high-precision multi-turn electric actuator according to claim 4, characterized in that: A fixed ruler (26) arranged parallel to the valve stem (16) is positioned on the inner side of the mounting bracket (24) through a mounting plate (28), and a movable ruler (25) is slidably arranged on the fixed ruler (26). The movable ruler (25) is synchronously connected to the connecting sleeve (29) through an adjustable screw (27).

6. The high-precision multi-turn electric actuator according to claim 5, characterized in that: The movable ruler (25) is provided with a high-precision display.

7. The high-precision multi-turn electric actuator according to claim 4, characterized in that: A bearing seat (19) is fixedly connected to the mounting bracket (24), and the nut sleeve (4) is positioned in the bearing seat (19) through at least two sets of bearings (21); the electric actuator (1) is fixedly connected to the bearing seat (19) through an actuator flange (3).

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