LU101907B1

LU101907B1 - Miniature electric actuator

Info

Publication number: LU101907B1
Application number: LU101907A
Authority: LU
Inventors: Chengxuan Cai; Min Yang; Fuqing Cai; Chengkai Yang; Dongwu Cai; Jing Cai; Yichen Cai; Dongmin Cai
Original assignee: Zhejiang Aoxiang Auto Control Tech Co Ltd
Priority date: 2019-09-24
Filing date: 2019-10-23
Publication date: 2021-01-11
Also published as: WO2021056649A1; CN110469706A

Abstract

The present invention discloses a miniature electric actuator, which includes a housing, a motor, a power output device and an over-torque protection device, characterized in that, the motor is disposed on a left side of the housing, the over-torque protection device is disposed on a right side of the housing, the power output device is disposed between the motor and the over-torque protection device, an upper end of the housing is provided with a cavity having a square cross section, a sealing cover is installed above the cavity, a travel switch and a micro switch are installed in the cavity, a rotating shaft of the over-torque protection device penetrates into the cavity to cooperate with the travel switch, and a main shaft of the power output device penetrates into the cavity to cooperate with the micro switch. The present invention changes the cavity to be a cube by a reasonable layout, and an opening of the cavity is square, which greatly increases the capacity of the cavity and has enough space to dispose the over-torque protection device, so that the miniature electric actuator has the over-torque protection function, which improves the safety of the actuator.

Description

| | 1/14 LU101907

MINIATURE ELECTRIC ACTUATOR Technical Field

[1] The present invention relates to an improved invention of an electric actuator, in particular to a micro-miniature electric actuator. Background |

[2] Atraditional electric actuator is large in size and heavy in weight, which is not | only inconvenient to install for a small valve, but also possible to crush the small valve | due to heavy weight. Therefore, the small valve needs to adopt a miniature electric | actuator which is small in size and light in weight. The existing miniature electric | actuator is reduced in size, but the layout is unreasonable, the explosion-proof | performance cannot be achieved, and the miniature electric actuator does not have functions such as over-torque protection and the like and belongs to a pseudo-miniature | electric actuator. | Summary .

[3] In view of the technical problems in the background, the technical problems ; solved by the present invention aim to provide a miniature electric actuator that is not . only small in size, but also has explosion-proof performance and an over-torque | protection function. |

[4] To solve the above technical problems, the present invention adopts the | following technical solutions: the miniature electric actuator includes a housing, a | motor, a power output device and an over-torque protection device, characterized in | that, the motor is disposed on a left side of the housing, the over-torque protection | eee

- : | | 2/14 LU101907 device is disposed on a right side of the housing, the power output device is disposed between the motor and the over-torque protection device, an upper end of the housing is provided with a cavity having a square cross section, a sealing cover is installed above the cavity, a travel switch and a micro switch are installed in the cavity, a rotating shaft of the over-torque protection device penetrates into the cavity to cooperate with the travel switch, and a main shaft of the power output device penetrates into the cavity to cooperate with the micro switch. |

[5] A lower end of the sealing cover is extended downward with an explosion- | proof retaining ring, a lower end surface of the sealing cover is stepped, and an upper | end of the cavity cooperates with the explosion-proof retaining ring in a plug manner. |

[6] A switch display is disposed above the sealing cover, the switch display | includes a switch indicating cover, the sealing cover is provided with a through hole, | the main shaft of the power output device passes through the cavity and the through | hole and are connected to the switch indicating cover above the sealing cover, and a | height of the through hole of the sealing cover deepens inward the cavity and forms an : explosion-proof surface. |

[7] A top of the main shaft has a vertical cut surface, a center of the switch | indicating cover has a slot, the slot matches the top of the main shaft, the switch display À 21 also includes a window cover, a surface of the window cover is divided into a gray È surface and a transparent surface, the window cover is disposed outside the switch | indicating cover in a cover manner, cross section of the switch indicating cover and the | window cover are circular, a lower end of the window cover is extended around with a | pressure plate, a pressure cover is sleeved outside the window cover, and the pressure | cover presses the pressure plate and is connected to the housing. |

[8] The over-torque protection device includes a worm shaft, an annular rack, a | hollow worm, and a worm wheel meshing with the hollow worm, the worm shaft is ı connected to an output shaft of the motor through a gear set, the annular rack and the |

| | 3/14 LU101907 hollow worm are both sleeved on the worm shaft, the worm shaft drives the hollow worm to rotate, bearings are installed at both ends of the worm shaft, the worm shaft is horizontally installed in the housing through the bearings, a spring is disposed between the bearings and the hollow worm, a gear is installed at a lower end of the rotating shaft, and the gear meshes with the annular rack.

[9] A first cam and a second cam are installed at an upper end of the rotating shaft, and the travel switch includes a first travel switch and a second travel switch which are disposed corresponding to the first cam and the second cam respectively. |

[10] The main shaft is coaxially connected to the worm wheel, a third cam, a fourth | cam and a transmission gear are installed at an upper end of the main shaft, the micro | switch includes a first micro switch and a second micro switch which are disposed | corresponding to the third cam and the fourth cam respectively, a potentiometer is also | installed in the cavity, and the transmission gear meshes with a gear of the potentiometer. |

[11] An output end of the main shaft is connected to a detachable connection | assembly, the connection assembly includes a connection sleeve and an installation end | cover, the connection sleeve is sleeved outside the main shaft, the installation end cover | is provided with a through hole, a diameter of the through hole is not less than an outer | diameter of the connection sleeve, and the installation end cover is detachably / connected to the housing. ;

[12] The connection sleeve and the main shaft are connected by a spline or a pin | key, the installation end cover is connected to the housing through an installation screw, : and the installation end cover is provided with a flow guide groove which is disposed | radially. :

[13] A first mechanical limit block and a second limit block are installed on the | housing, and a first convex block and a second convex block are installed on the main | shaft, which cooperate with the first limit block and the second limit block respectively. |

| 4/14 | [14] The present invention changes a cavity to be a cube by a reasonable layout, | and an opening of the cavity is square, which greatly increases the capacity ofthe cavity | so that the cavity is sufficient to accommodate parts such as a circuit board, a micro | switch, a travel switch and the like. Thus even if a housing is changed to be small in | size, the housing is complete and has enough space to dispose an over-torque protection | device, so that the miniature electric actuator has the over-torque protection function, | which improves the safety of the actuator; moreover, the cavity of the present invention | cooperates with a sealing cover in a plug manner, which realizes an explosion-proof | function and further improves the safety performance of the actuator.

| Brief Description of the Drawings | [15] FIG. 1 is a partial schematic diagram of the present invention.

| [16] FIG. 2 is a cross-sectional view taken along the line A-A in FIG. 1 of the | present invention.

| [17] FIG. 3 is a cross-sectional view along the direction K in FIG. 1 of the present | invention.

| [18] FIG. 4 is a top view of the present invention.

| [19] FIG. 5 is a cross-sectional view taken along the line N-O-N in FIG. 3 of the | present invention.

| [20] FIG. 6 is a cross-sectional view taken along the line F-F in FIG. 3 ofthe present | invention.

| [21] FIG. 7 is a left side view of the top of a main shaft of the present invention.

| [22] FIG. 8 is a schematic diagram of a switch display of the present invention.

| [23] FIG. 9 is a schematic diagram of a connection assembly of the present

| 5/14 | LU101907 | invention.

| Detailed Description of the Embodiments | [24] The related details and working principles of the implements and embodiments | of the present invention are described below with reference to the drawings. The | miniature electric actuator includes the housing 5, the motor 19, the power output | device 22, and the over-torque protection device 23. The motor 19 is disposed on the | left side of the housing 5, the over-torque protection device 23 is disposed on the right | side of the housing, and the power output device 22 is disposed between the motor 19 | and the over-torque protection device 23. The upper end of the housing is provided with | the cavity 34 having a square cross section, the sealing cover 50 is installed above the | cavity, and the travel switch 39 and the micro switch 37 are installed in the cavity 34. | The travel switch and the micro switch can be connected to a circuit board, and the | circuit board can also be installed in the cavity 34.

| [25] As shown in FIGS. 2 and 6, the over-torque protection device 23 includes the | rotating shaft 38, the worm shaft 25, the annular rack 28, the hollow worm 29, and the | worm wheel 31 meshing with the hollow worm. The worm shaft 25 is connected to the | output shaft 20 of the motor through the gear set 24. The annular rack 28 and the hollow | worm 29 are both sleeved on the worm shaft 25. The worm shaft drives the hollow | worm to rotate, and the hollow worm 29 and the worm shaft 25 are connected by a | spline or a pin key, so that the hollow worm can move axially on the worm shaft and | can also rotate with the worm shaft. The bearings 26 are installed at both ends of the | worm shaft 25 and the worm shaft 25 is horizontally installed in the housing 5 through | the bearings. The spring 30 is disposed between the bearing 26 and the hollow worm | 29, and the gear 27 is installed at the lower end of the rotating shaft 38. The gear meshes | with the annular rack 28. The upper end of the rotating shaft 38 penetrates into the | cavity 34. The cam 42 that cooperates with the travel switch 39 is installed at the upper

| end of the rotating shaft 38. When the cam 42 touches the travel switch 39, the travel | switch sends a signal to the electrical controller, and the electrical controller sends an ] instruction to the motor 19 to stop the operation thereof; as for the opening or closing | of the valve, the motor 19 will drive the rotating shaft 38 to rotate clockwise or | counterclockwise. The cam 42 on the rotating shaft is divided into a first cam and a | second cam, and the travel switch 39 includes a first travel switch and a second travel | switch which are disposed corresponding to the first cam and the second cam | respectively. When the valve is opened, the control is performed by the first cam and | the first travel switch, and when the valve is closed, the control is performed by the | second cam and the second travel switch.

| [26] As shown in FIGS. 1 and 5, the power output device 22 includes the main shaft | 4, which is coaxially connected to the worm wheel 31. The main shaft 4 penetrates into | the cavity 34 and cooperates with the micro switch 37. Similarly, the cam 41 that | cooperates with the micro switch is installed at the upper end of the main shaft 4. When | the cam touches the micro switch 37, the micro switch sends a signal to the electrical | controller, and the electrical controller sends an instruction to the motor 19 to stop the | operation thereof, which serves as a double protection; also as for the opening state or | closing state of the valve, the motor 19 will drive the main shaft to rotate clockwise or | counterclockwise. The cam on the main shaft is divided into a third cam and a fourth | cam, and the micro switch 37 includes a first micro switch and a second micro switch | which are disposed corresponding to the third cam and the fourth cam respectively. | When the valve is opened, the control is performed by the third cam and the first micro | switch, and when the valve is closed, the control is performed by the fourth cam and | the second micro switch; the potentiometer 35 is also installed in the cavity 34, and the ] potentiometer is a position sensor. The transmission gear 36 is installed at the upper end | of the main shaft 4. The transmission gear meshes with the gear 40 of the potentiometer. | The rotation of the main shaft 4 drives the rotation of the gear 40 of the potentiometer, | and the position of a valve stem is derived from the rotation angle of the gear. The

| potentiometer 35 sends information to the electrical controller which controls the motor | to operate, which is also one of over-torque protections; the first mechanical limit block | 32 and the second limit block 33 are installed on the housing 5, which correspond to | forward rotation and reverse rotation of the main shaft respectively. A first convex block | and a second convex block are installed on the main shaft, which cooperate with the | first limit block 32 and the second limit block 33 respectively. When the micro switch | 37 and the travel switch 39 fail, the first limit block and the second limit block restrict | the main shaft 4 from continuing to rotate, thereby avoiding damage to the valve.

| [27] The cavity of the present invention is a cube, and has enough space to | accommodate the circuit board 33, the potentiometer 35, the micro switch 37, the travel | switch 39, the first to fourth cams, and the transmission gear. The cavity 34 and the | sealing cover 50 of the present invention have explosion-proof performance; as shown | in FIG. 1, the lower end of the sealing cover 50 is extended downward with the | explosion-proof retaining ring 45, and the lower end surface of the sealing cover is | stepped. The upper end of the cavity 34 cooperates with the explosion-proof retaining | ring 45 in a plug manner, that is, the explosion-proof retaining ring 45 matches the | opening end of the cavity. The explosion-proof retaining ring 45 is inserted into the housing 5, and the contact surface between the explosion-proof retaining ring 45 and | the housing is the explosion-proof surface 46. When a spark is generated in the housing, | the explosion-proof surface 46 isolates the spark, extinguishes the spark in the housing | 5, and prevents the spark from leaking out of the housing, which improves safety | performance, The sealing ring 47 is disposed between the sealing cover 50 and the housing 5 to improve the sealing effect.

| [28] The switch display 21 is disposed above the sealing cover 50. As shown in FIG. | 4, the switch display includes the switch indicating cover 3. The sealing cover 50 is | provided with the through hole 48. The main shaft 4 of the power output device passes | through the cavity 34 and the through hole, and are connected to the switch indicating | cover 3 above the sealing cover. The height of the through hole of the sealing cover 50

| deepens inward the cavity and forms the explosion-proof surface 49. Similarly, the | disposition of the explosion-proof surface isolate the spark in the housing and improves | safety performance.

| [29] The switch display 21 also includes the window cover 2. The surface of the | switch indicating cover 3 is provided with the switch indicator 9. The window cover 2 | is disposed outside the switch indicating cover 3 in a cover manner. The window cover | 2 plays a protective role. Moreover the surface of the window cover 2 has the gray | surface 10 and the transparent surface 11. The gray surface 10 covers a part of the switch | indicator 9 on the switch indicating cover, and the switch indicator 9 on the switch | indicating cover can be seen through the transparent surface 11. The switch indicator 9 | seen by a staff through the transparent surface 11 is the state of the valve; the cross | sections of the switch indicating cover 3 and the window cover 2 are circular, and the | window cover 2 and the switch indicating cover 3 can rotate relative to each other. | When the main shaft 4 drives the switch indicating cover 3 to rotate, the window cover | 2 remains stationary. The staff can know the opening/closing state of the valve by the ] switch indicator 9 seen through the transparent surface. The staff can adjust the switch | display according to the position of the valve. First, the switch indicating cover 3 is | stationary, the window cover 2 is rotated, and the switch indicator 9 corresponding to | the transparent surface 11 is changed to achieve adjustment. Second, the window cover | 2 is stationary, the main shaft 4 is rotated to rotate the switch indicating cover 3, and | the switch indicator 9 corresponding to the transparent surface 11 is also changed to | achieve adjustment. The accuracy of switch indicating is improved by adjusting the | switching instruction, so that the staff can accurately know the opening or closing | situation of the valve. The switch indicating cover 3 is higher than the upper surface of = the housing 5, so that the staff can directly observe the switch indicator 9 and know the | state of the valve without ascending and looking down, and the operation is simpler | more intuitional. As shown in FIG. 2, the top of the main shaft 4 has the vertical cut | surface 8, and the center of the switch indicating cover 3 has a slot. The slot matches

| 9/14 | the top of the main shaft 4. During installing, it only needs to align the slot with the | main shaft 4 and press down the switch indicating cover 3 to insert the top of the main | shaft into the slot, which is very convenient for installation and disassembly; the vertical ) cut surface 8 prevents the switch indicating cover 3 from rotating relative to the main | shaft 4. In order to avoid damage to the window cover 2 due to installation problems, | the lower end of the window cover is extended around with the pressure plate 6. The | pressure plate is ring-shaped. The pressure cover 1 is sleeved outside the window cover | 2, presses the pressure plate 6, and is connected to the housing 5. The pressure cover 1 | and the housing 5 can be connected by screws, threads, glue, or the like. In this | embodiment, the pressure cover 1 is connected to the housing by screws and at least | three connection points are disposed. Generally, three or four connection points can be | used to install firmly. The pressure cover 1 of the present invention fixes the pressure | plate 6 on the housing 5. The pressure plate 6 is in surface contact with the housing 5, | and the force is a surface force. Therefore, the window cover 2 is not damaged and the | service life of the window cover is prolonged; the upper end surface of the housing is | provided with a circular sealing groove, the pressure plate is placed above the sealing | groove, and the sealing groove is provided with the sealing ring 7. The disposition of | the sealing ring improves the airtightness.

| [30] The lower end of the main shaft is connected to a detachable connection assembly. The connection assembly includes the connection sleeve 16 and the : installation end cover 15. The connection sleeve 16 is sleeved outside the main shaft 4. | The connection sleeve 16 and the main shaft 4 may be fixedly connected by screwed | connection or threaded connection. The screwed connection or the threaded connection | has advantage that not only the process is convenient but also the connection is firm. In | order to improve the stability of transmission, the connection sleeve 16 and the main | shaft 4 are connected by a spline or a pin key. In this embodiment, the connection sleeve | 16 and the main shaft 4 are connected by a spline, thus the rotation of the main shaft | will inevitably drive the connection sleeve to rotate; the installation end cover 15 is

| provided with the through hole 18, and the diameter of the through hole 18 is not less | than the outer diameter of the connection sleeve 16. The installation end cover is | sleeved outside the connection sleeve and is detachably connected to the housing. The | installation end cover can also be connected to the housing through installation screws | or the installation end cover is connected to threads. These two connection methods | have advantage that not only the process is convenient and the connection is firm, but | also the structure is simple and the disassembly/installation is convenient. The | installation end cover is connected to the valve, that is, the electric actuator is installed | on the valve via the installation end cover. The connection sleeve is connected to the | valve stem, the main shaft 4 rotates, and the valve stem is driven to operate by the | connection sleeve; the installation end cover is provided with the flow guide groove 17 . which is disposed radially, and the disposition of the flow guide groove guides a liquid | object to prevent the liquid object from entering the housing through the through hole | 18, and from affecting components such as the main shaft, the motor and the like in the | housing to be damaged. The present invention is directed to different models of valves. | Customers can choose a connection sleeve that matches the valve stem and sleeve the | connection sleeve on the main shaft, It is also very simple if the installation end cover | needs to be replaced. Therefore, the present invention is more practical and applicable to different models of valves, thereby greatly reducing equipment costs.

\ [31] The motor 19 drives the worm shaft 25 to rotate through the gear set 20, the | rotation of the worm shaft drives the hollow worm 29 to rotate, the hollow worm drives | the worm wheel 31 to rotate, and the main shaft 4 connected to the worm wheel rotates | accordingly. The rotation of the main shaft 4 drives the valve to open or close, and the | main shaft 4 simultaneously drives the switch indicating cover 3 to rotate. The staff | observes the state of the valve through the switch display 21, and when the main shaft | 4 rotates, the third cam, the fourth cam and the transmission gear on the main shaft | rotate; assume that the valve is opened when the motor 19 forward rotates, and if the | valve has been opened to the maximum, the motor 19 continues to rotate and the load

] of the worm wheel 31 increases.

The load force overcomes the elastic force of the front | end spring 30 on the worm shaft, so that the hollow worm moves forward on the worm | shaft to drive the annular rack 28 to move, the annular rack drives the gear 27 connected | to the rotating shaft to rotate counterclockwise, the rotating shaft rotates, and the first ] and second cams on the rotating shaft rotate, and the motor 19 stops rotating when the ; first cam is in contact with the first travel switch.

On the contrary, the valve is closed | when the motor 19 reversely rotates, and when the load of the worm wheel increases, | the load force overcomes the elastic force of the rear end spring on the worm shaft.

The | hollow worm and the annular rack move backward, so that the gear 27 rotates clockwise, | the rotation of the gear drives the rotating shaft and the first and second cams on the | rotating shaft to rotate clockwise, and the motor 19 stops rotating when the second cam | is in contact with the second travel switch; similarly, if the motor forward rotates, the | motor 19 stops rotating when the third cam on the main shaft 4 is in contact with the | first micro switch.

If the motor reversely rotates, the motor 19 also stops rotating when | the fourth cam on the main shaft 4 is in contact with the second micro switch; the motor | 19 stops rotating if the rotation angle of the gear 40 of the potentiometer 35 is the | maximum angle at which the valve has been opened.

When the valve is fully opened, | the above ihree situations can make the motor 19 stop rotating, thereby avoiding | damage to the valve and valve stem.

Even if the above potentiometer 35, the micro | switch 37, and travel switch 39 all fail, it is also possible to limit the rotation of the | main shaft by mechanical limit, that is, when the first limit block 32 is in contact with | the first convex block, the clockwise rotation of the main shaft is restricted, and when | the second limit block 33 is in contact with the second convex block, the | counterclockwise rotation of the main shaft is restricted.

The present invention uses | multiple over-torque protections to protect the valve to the maximum extent and | improve safety performance.

Claims

Claims What is claimed is:

1. À miniature electric actuator including a housing, a motor, a power output device and an over-torque protection device, characterized in that, the motor is disposed on a left side of the housing, the over-torque protection device is disposed on a right side of the housing, the power output device is disposed between the motor and the over-torque protection device, an upper end of the housing is provided with a cavity having a square cross section, a sealing cover is installed above the cavity, a travel switch and a micro switch are installed in the cavity, a rotating shaft of the over-torque protection device penetrates into the cavity to cooperate with the travel switch, and a main shaft of the power output device penetrates into the cavity to cooperate with the micro switch.

2. The miniature electric actuator according to claim 1, characterized in that, a lower end of the sealing cover is extended downward with an explosion-proof retaining ring, a lower end surface of the sealing cover is stepped, and an upper end of the cavity cooperates with the explosion-proof retaining ring in a plug manner.

3. The miniature electric actuator according to claim 1, characterized in that, a switch display is disposed above the sealing cover, the switch display includes a switch indicating cover, the sealing cover is provided with a through hole, the main shaft of the power output device passes through the cavity and the through hole and are connected to the switch indicating cover above the sealing cover, and a height of the through hole of the sealing cover deepens inward the cavity and forms an explosion- proof surface.

4. The miniature electric actuator according to claim 3, characterized in that, a top of the main shaft has a vertical cut surface, a center of the switch indicating cover has a ; slot, the slot matches the top of the main shaft, the switch display 21 also includes a | window cover, a surface of the window cover is divided into a gray surface and a transparent surface, the window cover is disposed outside the switch indicating cover in a cover manner, cross section of the switch indicating cover and the window cover are circular, a lower end ofthe window cover is extended around with a pressure plate, a pressure cover is sleeved outside the window cover, and the pressure cover presses the pressure plate and is connected to the housing. |

5. The miniature electric actuator according to claim 1, characterized in that, the over- | torque protection device includes a worm shaft, an annular rack, a hollow worm, and a | worm wheel meshing with the hollow worm, the worm shaft is connected to an output | shaft of the motor through a gear set, the annular rack and the hollow worm are both | sleeved on the worm shaft, the worm shaft drives the hollow worm to rotate, bearings [ are installed at both ends of the worm shaft, the worm shaft is horizontally installed in | the housing through the bearings, a spring is disposed between the bearings and the | hollow worm, a gear is installed at a lower end of the rotating shaft, and the gear meshes | with the annular rack. |

6. The miniature electric actuator according to claim 5, characterized in that, a first cam | and a second cam are installed at an upper end of the rotating shaft, and the travel switch | includes a first travel switch and a second travel switch which are disposed | corresponding to the first cam and the second cam respectively. |

7. The miniature electric actuator according to claim 5, characterized in that, the main |

| 14/14 LU101907 shaft is coaxially connected to the worm wheel, a third cam, a fourth cam and a transmission gear are installed at an upper end of the main shaft, the micro switch includes a first micro switch and a second micro switch which are disposed corresponding to the third cam and the fourth cam respectively, a potentiometer is also installed in the cavity, and the transmission gear meshes with a gear of the potentiometer. |

8. The miniature electric actuator according to claim 1, characterized in that, an output | end of the main shaft is connected to a detachable connection assembly, the connection | assembly includes a connection sleeve and an installation end cover, the connection | sleeve is sleeved outside the main shaft, the installation end cover is provided with a | through hole, a diameter of the through hole is not less than an outer diameter of the | connection sleeve, and the installation end cover is detachably connected to the housing. |

9. The miniature electric actuator according to claim 8, characterized in that, the | connection sleeve and the main shaft are connected by a spline or a pin key, the i installation end cover is connected to the housing through an installation screw, and the / installation end cover is provided with a flow guide groove which is disposed radially. |

10. The miniature electric actuator according to claim 1, characterized in that, a first | mechanical limit block and a second limit block are installed on the housing, and a first | convex block and a second convex block are installed on the main shaft, which : cooperate with the first limit block and the second limit block respectively. |