Anti-overload mechanism of electric actuator

Abstract

The application relates to an anti-overload mechanism of an electric actuator, which comprises a motor, the output shaft of the motor is connected with a worm through a shaft coupling, the worm is engaged with a worm wheel, the worm wheel and the worm are externally provided with a box, the rotating shaft of the worm wheel is connected with a valve, the worm comprises a worm sleeve and a worm shaft, the worm sleeve is rotationally connected on the worm shaft, a baffle and a disc spring are further sleeved on the worm shaft, the baffle rotates together with the worm shaft, the baffle is in contact with the two end faces of the worm sleeve, a circle of steel balls are arranged in the baffle, grooves for containing the steel balls are arranged on the end faces of the worm sleeve, the disc spring is used for pushing the baffle to the end faces of the worm sleeve, the worm sleeve is provided with a clamping groove, and a torque adjusting mechanism is further arranged, and the adjusting rod of the torque adjusting mechanism extends into the clamping groove.

Description

Technical Field

[0001] This invention belongs to the field of torque regulation technology, and more specifically, relates to an overload protection mechanism for an electric actuator. Background Technology

[0002] Electric actuators, as core mechatronic devices in the field of automation control, mainly convert electrical energy into mechanical motion to achieve automatic control of equipment such as valves and baffles. They are widely used in many fields such as chemical industry, drainage, and industrial automation. Their torque regulation accuracy and operational stability directly determine the operating efficiency and reliability of the entire automation control system.

[0003] CN214008221U discloses a sliding worm gear driven valve electric actuator. The worm sleeve is slidably connected to the worm shaft by a spline and can slide on the worm shaft. Disc springs are connected to both ends of the worm sleeve. The worm sleeve is provided with a radial connecting groove, and the main shaft of the torque controller extends into the radial connecting groove.

[0004] This structure uses a torque controller to adjust the position of the worm gear sleeve, thereby adjusting the clamping force of the disc spring. The clamping force of the disc spring, in turn, determines the maximum torque that the worm gear can transmit.

[0005] When this mechanism is overloaded, the worm sleeve continues to rotate, but the worm wheel is not driven. At this time, the teeth on the worm and the teeth on the worm wheel will rub against each other, causing tooth surface wear and a lot of heat. Therefore, it is necessary to improve it. Summary of the Invention

[0006] To solve the above-mentioned technical problems, the present invention provides an overload protection mechanism for an electric actuator, which prevents the teeth on the worm and the teeth on the worm wheel from sliding against each other when overloaded.

[0007] To achieve the above objectives, the present invention provides the following technical solution: an overload protection mechanism for an electric actuator, comprising a motor, the output shaft of which is connected to a worm gear via a coupling, the worm gear meshing with a worm wheel, a housing provided outside the worm wheel and the worm gear, the rotating shaft of the worm wheel being connected to a valve, the worm gear comprising a worm sleeve and a worm shaft, the worm sleeve being rotatably connected to the worm shaft, a baffle and a disc spring also being fitted on the worm shaft, the baffle rotating together with the worm shaft, the baffle contacting the two end faces of the worm sleeve, a ring of steel balls being provided inside the baffle, a groove for accommodating the steel balls being provided on the end face of the worm sleeve, the disc spring being used to push the baffle towards the end face of the worm sleeve, the worm sleeve being provided with a slot, and a torque adjustment mechanism further comprising a torque adjustment mechanism, the adjusting rod of which extends into the slot. In use, the motor drives the worm shaft to rotate via the output shaft, the baffle on the worm shaft drives the worm sleeve to rotate via the steel balls, and the rotation of the worm sleeve in turn drives the worm wheel to rotate. If the valve plate gets stuck or the set torque is exceeded, the steel ball will slide out of the groove. At this point, the rotation of the worm shaft cannot drive the worm sleeve to rotate, meaning the worm sleeve won't rotate. This prevents the teeth on the worm wheel and worm from rubbing against each other, thus avoiding wear and heat. Furthermore, the rotation of the baffle on the worm wheel sleeve is converted into rolling friction due to the addition of the steel ball, greatly reducing frictional resistance and preventing wear between the worm wheel sleeve and the baffle. During the process, adjusting the position of the worm wheel sleeve through the torque adjustment mechanism can adjust the clamping force between the baffle and the end face of the worm wheel sleeve, thereby adjusting the torque that the worm shaft can transmit to the worm sleeve.

[0008] In the above technical solution, preferably, the baffle includes a base and a cover plate. The base has a ring of cavities, and the steel ball is disposed within the cavities. The cover plate is fixed to the base and has a ring of through holes. The diameter of the through holes is smaller than the diameter of the steel ball, and a portion of the steel ball passes through the through holes and extends out of the cover plate. This is a specific structure of the baffle.

[0009] In the above technical solution, preferably, the bottom of the baffle is provided with a sliding groove, a sliding sleeve is fixed on the worm shaft, and the outer ring of the sliding sleeve is provided with a protrusion that cooperates with the sliding groove. This is a specific way in which the baffle and the worm shaft are connected to each other.

[0010] In the above technical solution, preferably, each disc spring is divided into a first part and a second part, the first part and the second part rotate in opposite directions, and the middle area of ​​the first part and the second part overlaps. This design ensures that even if one part fails, the other part of the disc spring can still function.

[0011] In the above technical solution, preferably, conductive rings are provided on the baffle and the worm gear sleeve. When the steel ball is inserted into the groove, the two conductive rings contact each other. When the steel ball slides out of the groove, the two conductive rings separate. A carbon brush is provided on the housing, and the conductive rings contact the carbon brush. The carbon brush is connected in series with the motor coil via a wire. With this design, when the system torque exceeds the set value, the steel ball slides out of the groove. At this time, a certain gap will appear on the end face of the baffle and the worm gear sleeve. This gap allows the two conductive rings to separate, thus disconnecting the motor coil and stopping the motor when the motor is turned on, avoiding idle rotation.

[0012] In the above technical solution, preferably, the housing has a through hole penetrating the shell, and a frame made of insulating material is disposed within the through hole. The carbon brush is disposed within the frame, and a spring is also disposed within the frame to push the carbon brush towards the conductive ring. This is a specific method of carbon brush installation.

[0013] In the above technical solution, preferably, the worm shaft includes an intermediate section and extension sections connected to both ends of the intermediate section. The diameter of the intermediate section is larger than the diameter of the extension sections. The worm sleeve is rotatably connected to the intermediate section, and the sliding sleeve is fixed to the extension sections. The end face of the sliding sleeve is in contact with the end face of the intermediate section.

[0014] Compared with the prior art, the present invention has the following advantages: In operation, the motor drives the worm shaft to rotate via its output shaft. A baffle on the worm shaft, through a steel ball, drives the worm sleeve to rotate, which in turn drives the worm wheel. If the valve plate jams or the set torque is exceeded, the steel ball will slide out of the groove. In this case, the rotation of the worm shaft cannot drive the worm sleeve to rotate, meaning the worm sleeve stops rotating. This prevents the teeth on the worm wheel and worm from rubbing against each other, thus avoiding wear and heat. Furthermore, the rotation of the baffle on the worm sleeve, due to the addition of the steel ball, is converted into rolling friction, greatly reducing frictional resistance and preventing wear between the worm sleeve and the baffle. During operation, adjusting the position of the worm sleeve via the torque adjustment mechanism adjusts the clamping force between the baffle and the end face of the worm sleeve, thereby adjusting the torque that the worm shaft can transmit to the worm sleeve.

[0015] The specific embodiments of the present invention will now be described in further detail with reference to the accompanying drawings. Attached Figure Description

[0016] In the attached diagram: Figure 1 This is a schematic diagram of the present invention.

[0017] Figure 2 This is a top view (sectional view) of the present invention.

[0018] Figure 3 for Figure 2 A magnified view of a portion of the image.

[0019] Figure 4 for Figure 2 A cross-sectional view along AA.

[0020] Figure 5 This is a schematic diagram of a 4-disc spring.

[0021] In the diagram: 1. Motor, 11. Output shaft, 2. Coupling, 3. Worm, 31. Worm sleeve, 311. Groove, 32. Worm shaft, 321. Intermediate section, 322. Extension section, 33. Sliding sleeve, 331. Protrusion, 4. Worm wheel, 5. Housing, 51. Carbon brush, 52. Through hole, 53. Frame, 54. Spring, 6. Baffle, 61. Steel ball, 62. Base, 621. Cavity, 63. Cover plate, 631. Through hole, 64. Slide groove, 7. Disc spring, 71. First part, 72. Second part, 8. Torque adjustment mechanism, 9. Conductive ring. Detailed Implementation

[0022] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments will be clearly and completely described below with reference to the accompanying drawings. The following embodiments are used to illustrate the present invention.

[0023] like Figures 1 to 5 As shown, an overload protection mechanism for an electric actuator includes a motor 1. The output shaft 11 of the motor 1 is connected to a worm gear 3 via a coupling 2. The worm gear 3 meshes with a worm wheel 4. A housing 5 is provided outside the worm wheel 4 and the worm gear 3. The rotating shaft of the worm wheel 4 is connected to a valve.

[0024] The worm 3 includes a worm sleeve 31 and a worm shaft 32. The worm shaft 32 includes an intermediate section 321 and extension sections 322 connected to both ends of the intermediate section. The diameter of the intermediate section 321 is larger than the diameter of the extension sections 322. The worm sleeve 31 is rotatably connected to the intermediate section 321.

[0025] A baffle 6 and a disc spring 7 are also fitted on the worm shaft 32. The baffle 6 rotates together with the worm shaft and contacts both ends of the worm sleeve 31. A ring of steel balls 61 is provided inside the baffle 6. A groove 311 for accommodating the steel balls is provided on the end face of the worm sleeve 31. The disc spring 7 is used to push the baffle 6 toward the end face of the worm sleeve 31. The worm sleeve 31 is provided with a slot 312 and also includes a torque adjustment mechanism 8. The adjusting rod of the torque adjustment mechanism 8 extends into the slot 312.

[0026] The baffle 6 includes a base 62 and a cover plate 63. The base 62 has a ring of cavities 621, and the steel ball 61 is disposed within the cavities 621. The cover plate 63 is fixed to the base 62 and has a ring of through holes 631. The diameter of the through holes 631 is smaller than the diameter of the steel ball 61, and a portion of the steel ball 61 extends through the through holes 631 and out of the cover plate. This is a specific baffle structure.

[0027] The bottom of the baffle 6 is provided with a sliding groove 64, and a sliding sleeve 33 is fixed on the worm shaft 32. The sliding sleeve is fixed on the extension section, and the end face of the sliding sleeve is in contact with the end face of the middle section.

[0028] The outer ring of the sliding sleeve 33 is provided with a protrusion 331 that mates with the sliding groove 64. This is a specific way in which the baffle and the worm shaft are connected to each other.

[0029] Each disc spring 7 is divided into a first part 71 and a second part 72, the first part and the second part rotating in opposite directions, and the middle area of ​​the first part and the second part overlapping. This design ensures that even if one part fails, the other part of the disc spring can still function.

[0030] Conductive rings 9 are provided on the baffle 6 and the worm gear sleeve 31. When the steel ball is inserted into the groove, the two conductive rings contact each other. When the steel ball slides out of the groove, the two conductive rings separate. A carbon brush 51 is provided on the housing 5, and the conductive rings 9 contact the carbon brush 51. The carbon brush 51 is connected in series with the coil of the motor 1 through a wire. With this design, when the torque of the system exceeds the set value, the steel ball slides out of the groove. At this time, a certain gap will appear on the end face of the baffle and the worm gear sleeve. This gap allows the two conductive rings to separate, and the motor coil is disconnected. The motor stops rotating immediately upon clicking, avoiding idle rotation.

[0031] The housing 5 has a through hole 52 penetrating the shell. A frame 53 made of insulating material is installed inside the through hole 52. The carbon brush 51 is installed inside the frame 53. A spring 54 is also installed inside the frame 53 to push the carbon brush 51 toward the conductive ring 9. This is a specific method of carbon brush installation.

[0032] In operation, the motor drives the worm shaft to rotate via its output shaft. A baffle on the worm shaft, through a steel ball, drives the worm sleeve to rotate, which in turn drives the worm wheel. If the valve plate jams or the set torque is exceeded, the steel ball will slide out of the groove. In this case, the rotation of the worm shaft cannot drive the worm sleeve to rotate, meaning the worm sleeve stops rotating. This prevents the teeth on the worm wheel and worm from rubbing against each other, thus avoiding wear and heat. Furthermore, the rotation of the baffle on the worm sleeve, due to the addition of the steel ball, is converted into rolling friction, greatly reducing frictional resistance and preventing wear between the worm sleeve and the baffle. During operation, adjusting the position of the worm sleeve via the torque adjustment mechanism adjusts the clamping force between the baffle and the end face of the worm sleeve, thereby adjusting the torque that the worm shaft can transmit to the worm sleeve.

[0033] Finally, it should be noted that the above descriptions are merely preferred embodiments of the present invention and are not intended to limit the present invention. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. An overload protection mechanism for an electric actuator, comprising a motor, wherein the output shaft of the motor is connected to a worm gear via a coupling, the worm gear meshes with a worm wheel, a housing is provided outside the worm wheel and the worm gear, and the shaft of the worm wheel is connected to a valve, characterized in that: The worm gear includes a worm sleeve and a worm shaft. The worm sleeve is rotatably connected to the worm shaft. A baffle and a disc spring are also sleeved on the worm shaft. The baffle rotates together with the worm shaft and contacts both end faces of the worm sleeve. A ring of steel balls is provided inside the baffle. A groove for accommodating the steel balls is provided on the end face of the worm sleeve. The disc spring is used to push the baffle towards the end face of the worm sleeve. The worm sleeve is provided with a retaining groove and also includes a torque adjustment mechanism. The adjusting rod of the torque adjustment mechanism extends into the retaining groove.

2. The overload protection mechanism for an electric actuator according to claim 1, characterized in that, The baffle includes a base and a cover plate. The base has a ring of cavities, and the steel ball is placed inside the cavities. The cover plate is fixed to the base and has a ring of through holes. The diameter of the through holes is smaller than the diameter of the steel ball, and part of the steel ball extends out of the cover plate through the through holes.

3. The overload protection mechanism for an electric actuator according to claim 2, characterized in that, The bottom of the baffle is provided with a sliding groove, and a sliding sleeve is fixed on the worm shaft. The outer ring of the sliding sleeve is provided with a protrusion that cooperates with the sliding groove.

4. The overload protection mechanism for an electric actuator according to claim 3, characterized in that, Each disc spring is divided into a first part and a second part, the first part and the second part rotate in opposite directions, and the middle area of ​​the first part and the second part overlaps.

5. The overload protection mechanism for an electric actuator according to claim 3, characterized in that, Conductive rings are provided on the baffle and the worm gear sleeve. When the steel ball is inserted into the groove, the two conductive rings come into contact with each other. When the steel ball slides out of the groove, the two conductive rings separate from each other. A carbon brush is provided on the housing. The conductive rings come into contact with the carbon brush. The carbon brush is connected in series with the coil of the motor through a wire.

6. The overload protection mechanism for an electric actuator according to claim 5, characterized in that, The housing has a through hole that penetrates the shell. A frame made of insulating material is installed inside the through hole. The carbon brush is installed inside the frame. A spring is also installed inside the frame to push the carbon brush toward the conductive ring.

7. The overload protection mechanism for an electric actuator according to claim 3, characterized in that, The worm shaft includes an intermediate section and extension sections connected to both ends of the intermediate section. The diameter of the intermediate section is larger than the diameter of the extension sections. The worm sleeve is rotatably connected to the intermediate section, and the sliding sleeve is fixed to the extension sections. The end face of the sliding sleeve is in contact with the end face of the intermediate section.

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