CN117515251A - Motor-driven actuator and electric control valve - Google Patents

Abstract

The invention relates to a motor-driven actuator, which comprises a motor (1), a controller (2) for controlling the motor (1), a floating connection structure (4) for connecting a valve core, a transmission structure for transmitting power output by the motor (1) to the floating connection structure (4), a rotary encoder (5) and an interface (6), wherein one end of the interface (6) is electrically connected with the controller (2), the other end of the interface (6) is electrically connected with an external circuit, the output end of the rotary encoder (5) is connected with the controller (2), the controller (2) can acquire the displacement of the valve core through the rotary encoder (5), and the controller (2) can control the motor (1) through comparing the displacement of the valve core with the expected displacement of the valve core so that the displacement of the valve core is equal to the expected displacement of the valve core. In addition, the invention also relates to an electric control valve comprising the motor-driven actuator. The motor driving actuator has the advantages of strong adaptability, convenient installation and high control precision.

Description

Motor-driven actuator and electric control valve

Technical Field

The present invention relates to electrically controlled valves, and in particular to a motor driven actuator. Further, the invention relates to an electrically controlled valve comprising the motor driven actuator.

Background

The hydraulic control is used as an important control mode of modern engineering mechanical equipment, hydraulic oil is used as a working medium, and a hydraulic system is controlled and power is transmitted. In order to improve the performance of a hydraulic system and realize the digitization and the intellectualization of engineering machinery, more and more hydraulic elements are combined with electronic systems and computer control technologies to form a novel hydraulic technology, namely a digital hydraulic technology, which has become a current research hot spot.

The digital valve in the prior art is used for controlling the valve core to move through a motor, a valve core control module is often integrated in a valve body after corresponding programs are downloaded in a valve core controller, and the valve core controller is integrated in the valve body for different application occasions, so that parameter setting is difficult to adjust, a plurality of types of digital valves are needed in one large-scale mechanical equipment, even a plurality of manufacturers of digital valves are needed, a large amount of time is needed for selecting the digital valves due to different structural designs and communication protocols of the digital valves, the installation and the debugging of the digital valves are hindered, the production efficiency is reduced, the valve core control module of the digital valve is difficult to adapt to defects of various working conditions and the universality of digital hydraulic technical requirements is contrary, the existing digital valve mainly controls the valve core through a stepping motor, and the stepping motor has the defects of high cost, low response speed, low frequency response and poor adaptability to the practical application environment.

In view of the foregoing, there is a need for a motor-driven actuator that overcomes the above-described technical problems and effectively solves or alleviates the above-described technical drawbacks.

Disclosure of Invention

The technical problem to be solved by the invention is to provide a motor-driven actuator which has wider adaptability.

Further, the technical problem to be solved by the invention is to provide an electric control valve which has wider adaptability.

In order to solve the technical problems, the invention provides a motor driving actuator, which comprises a motor, a controller for controlling the motor, a floating connection structure for connecting a valve core, a transmission structure for transmitting power output by the motor to the floating connection structure, a rotary encoder and an interface, wherein one end of the interface is electrically connected with the controller, the other end of the interface is electrically connected with an external circuit, the output end of the rotary encoder is connected with the controller, the controller can acquire the displacement of the valve core through the rotary encoder, and the controller can control the motor by comparing the displacement of the valve core with the expected displacement of the valve core so that the displacement of the valve core is equal to the expected displacement of the valve core.

Preferably, the controller is capable of controlling the motor to compensate for joint play of the floating connection.

Preferably, the controller is capable of controlling the motor to move the valve spool to a null position.

Specifically, the rotary encoder is an optoelectronic encoder.

Preferably, the transmission structure comprises a rack and a reduction gear set, one end of the rack is connected with the floating connection structure, the other end of the rack is meshed with the last stage of gear in the reduction gear set, and the first stage of gear in the reduction gear set is meshed with the motor.

Preferably, the motor is a brushless motor.

Preferably, the motor-driven actuator further includes a housing formed with a rack guide cavity and a floating connection structure guide cavity, the rack is disposed in the rack guide cavity, the floating connection structure is disposed in the floating connection structure guide cavity, the reduction gear set is capable of driving the rack to move along the rack guide cavity under the driving of the motor, and the rack is capable of driving the floating connection structure to move along the floating connection structure guide cavity.

Specifically, the motor-driven actuator further comprises a housing, a stop piece is formed on a last gear of the reduction gear set, a stop piece corresponding to the stop piece is formed on the housing, the rack can move from a first position to a second position under the drive of the motor, the stop piece is limited by the stop piece when the rack is in a state of the first position, and one end, far away from the floating connection structure, of the rack abuts against the housing when the rack is in a state of the second position.

Specifically, the rotary encoder is arranged at the last stage of reduction gears in the reduction gear set, and can acquire the angular displacement of the last stage of reduction gears and feed back to the controller.

On the basis of the technical scheme of the motor-driven actuator, the invention provides an electric control valve, which comprises the motor-driven actuator.

Through the technical scheme, the motor-driven actuator can be used as an independent element, the independent motor-driven actuator is connected with the valve core in the valve body through the floating connection structure, the installation precision requirement when the motor-driven actuator is installed in the valve body is reduced, the installation is simpler, the valve core and the transmission structure are protected, the problems of eccentricity, valve core bending, rack bending and the like are avoided, the motor-driven actuator can obtain the displacement of the valve core through the rotary encoder and feed back to the controller, the motor-driven actuator can control the valve core to move more accurately, the valve core displacement precision is ensured, in addition, the motor-driven actuator is provided with an interface, when a user needs to adjust the parameters of the motor-driven actuator according to own requirements, the interface can be connected to a downloading circuit, the parameters are adjusted, the interface can be connected with a controller of the mechanical equipment when the motor-driven actuator is applied to the mechanical equipment, thereby controlling the motor-driven actuator through a control signal sent by the controller of the mechanical equipment, the corresponding valve core to move, the motor-driven actuator can be controlled by the control signal, and the corresponding valve core can be known, for example, the motor-driven actuator can be automatically controlled by the motor-driven actuator in the same protocol, and the automobile-driven controller can be conveniently installed in various automobile-driven-related automobile-control devices, and the automobile-used in the automobile-used drive equipment, the automobile-used for realizing the same protocol, and the automobile-used control system can be well-driven by the automobile controller, and can be conveniently and well-controlled by the automobile controller, and can be well driver control and the automobile controller, the efficiency of production and design is increased.

Additional features and advantages of embodiments of the invention will be set forth in the detailed description which follows.

Drawings

FIG. 1 is a schematic view of a motor driven actuator according to an embodiment of the present invention;

fig. 2 is a schematic diagram of the operation of a motor-driven actuator according to an embodiment of the present invention.

Description of the reference numerals

1 motor 2 controller

3 rack 4 floating connection structure

5 rotary encoder 6 interface

7-shell 8-rack guide cavity

9 floating connection structure guide cavity 10 first stage reduction gear

11 second stage reduction gear 12 third stage reduction gear

Detailed Description

Embodiments of the present application are described in further detail below with reference to the accompanying drawings and examples. The following detailed description of the embodiments and the accompanying drawings are provided to illustrate the principles of the present application and not to limit the scope of the application, which may be embodied in many different forms and not limited to the specific embodiments of the application herein, but include all technical solutions falling within the scope of the claims.

These embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the disclosure to those skilled in the art. It should be noted that: the relative arrangement of parts and steps, the composition of materials, and the like set forth in these examples should be construed as merely illustrative, and not a limitation, unless specifically indicated otherwise.

In the description of the present application, unless otherwise indicated, the meaning of "plurality" is greater than or equal to two; the terms "left," "right," "inner," "outer," and the like indicate an orientation or positional relationship merely for convenience of description and to simplify the description, and do not indicate or imply that the devices or elements referred to must have a particular orientation, be constructed and operate in a particular orientation, and therefore should not be construed as limiting the present application. When the absolute position of the object to be described is changed, the relative positional relationship may be changed accordingly.

Furthermore, the terms "first," "second," and the like, as used herein, do not denote any order, quantity, or importance, but rather are used to distinguish one element from another. The word "comprising" or "comprises" and the like means that elements preceding the word encompass the elements recited after the word, and not exclude the possibility of also encompassing other elements.

It should also be noted that, in the description of the present application, unless explicitly specified and limited otherwise, the terms "mounted," "connected," and "connected" are to be construed broadly, and may be either fixedly connected, detachably connected, or integrally connected, for example; can be directly connected or indirectly connected through an intermediate medium. The specific meaning of the terms in the present application can be understood as appropriate by one of ordinary skill in the art. When a particular device is described as being located between a first device and a second device, there may or may not be an intervening device between the particular device and either the first device or the second device.

All terms used herein have the same meaning as understood by one of ordinary skill in the art to which this application pertains, unless specifically defined otherwise. It should be understood that references herein to "displacement of the spool" are not entirely accurate spool displacements, and that errors may exist within the allowable range. It will be further understood that terms, such as those defined in commonly used dictionaries, should be interpreted as having a meaning that is consistent with their meaning in the context of the relevant art and will not be interpreted in an idealized or overly formal sense unless expressly so defined herein.

Techniques, methods, and apparatus known to one of ordinary skill in the relevant art may not be discussed in detail, but where appropriate, the techniques, methods, and apparatus should be considered part of the specification.

Referring to fig. 1, the present application provides a motor-driven actuator, the motor-driven actuator includes a motor 1, a controller 2 for controlling the motor 1, a floating connection structure 4 for connecting a valve core, a transmission structure for transmitting power output by the motor 1 to the floating connection structure 4, a rotary encoder 5 and an interface 6, one end of the interface 6 is electrically connected with the controller 2, the other end of the interface 6 is electrically connected with an external circuit, the output end of the rotary encoder 5 is connected with the controller 2, the external circuit transmits a displacement control signal to the controller 2 through the interface 6, the controller 2 controls the rotation direction and the angular displacement amount of the motor 1 according to the received displacement control signal, the motor 1 drives the floating connection structure 4 to drive the valve core to move through the floating connection structure 4, the rotary encoder 5 can be arranged near the transmission structure, the displacement of the valve core can be indirectly obtained through obtaining the angular displacement of a transmission part in the transmission structure and feeding back to the controller 2 according to the angular displacement, the controller 2 can further control the motor 1 through comparing the displacement with the desired displacement, so that the valve core displacement can perform accurate valve core movement control for the desired displacement. The motor driven actuator is connected with the valve core through the floating connection structure 4, and is connected with the displacement output mechanism and the displacement actuating mechanism through the floating connection structure 4, so that the connection precision requirement for connection with the valve core is reduced, the installation is more convenient, the suitability of the motor driven actuator is improved, the valve core and the transmission structure are also protected, the service life of an electric control valve using the motor driven actuator is prolonged, compared with a direct contact type connection mode, the displacement output mechanism and the displacement actuating mechanism are separated when in reverse pulling, at the moment, the displacement actuating mechanism needs to return through a spring, the valve core is driven to move through the floating connection structure 4 when in reverse pulling, the problem of different parts of the displacement output mechanism and the displacement actuating mechanism when the motor rotates is avoided, the response speed and the following performance of the displacement actuating mechanism are ensured, the motor-driven actuator is provided with an interface 6, under the condition that the system principle or the structural design is not required to be changed, the corresponding external circuit can be directly connected through the interface 6 to realize the function of parameter adjustment, the suitability of the motor-driven actuator is further improved, the motor-driven actuator can also be connected with an external controller through the interface 6, the control signal of the external controller is received or the data acquired by the motor-driven actuator is uploaded to the external controller, the motor-driven actuator can be connected with various valve bodies, the suitability is higher, therefore, the motor-driven actuator can be used at various positions on one mechanical device, the intelligent system is realized through the unified control of the controller of the mechanical device, and the unified specification can be formed in the design and the installation process because the structural design and the communication protocol of each motor-driven actuator are the same, the efficiency of production and design is improved.

As a preferred implementation manner, the controller 2 of this embodiment can control the motor 1 to compensate the joint gap of the floating connection structure 4, and the motor driving actuator of this application connects the displacement actuating mechanism and the displacement output mechanism through the floating connection structure 4, so when the moving direction of the displacement output mechanism changes, because the floating connection structure 4 has the joint gap, the displacement output mechanism needs to move the joint gap and then drives the valve core to move through the floating connection structure 4, so that the actual displacement of the valve core is slightly smaller, while the controller 2 of this embodiment can control the motor 1 to compensate the joint gap, so as to ensure the displacement precision, and it can be expected by those skilled in the art on the basis of the technical scheme of this application that the rotating structure has the mechanical gap, and the controller 2 can control the motor 1 to compensate the mechanical gap, so as to further improve the displacement precision.

As a preferred implementation manner, the controller 2 in the motor-driven actuator of the embodiment can control the motor 1 to move the valve core to the zero position, when the maximum stroke of the motor-driven actuator of the embodiment is not less than the valve core stroke of the valve body connected with the motor-driven actuator, the motor-driven actuator and the valve body can be directly connected without correcting the valve core of the valve body to the zero position, after the motor-driven actuator is electrified, a control signal can be sent out to enable the motor-driven actuator to automatically perform zero position calibration, namely, the motor 1 is controlled to rotate to drive the transmission structure, the transmission structure drives the rack 3 to extend or retract until the valve core is limited by one side cavity wall of the valve cavity, the controller 2 is controlled to reversely rotate, the transmission structure drives the rack 3 to reversely move until the valve core is limited by the other side cavity wall of the valve cavity, and the controller 2 is controlled to record the position value at the moment, so that the controller 2 can acquire the valve core according to the position values at two sides, and the controller 2 can control the motor 1 to drive the valve core to be corrected to the zero position through the reduction gear set, the rack 3 and the floating connection structure 4, the motor-driven actuator of the embodiment can conveniently install the motor and the valve core to the zero position correction by means of the motor-driven actuator of the embodiment, the motor-driven actuator and the actuator of the embodiment and the universal actuator can not be conveniently correct the zero position value.

As a specific embodiment, the rotary encoder 5 is an optoelectronic encoder capable of measuring the angular displacement of a part of the components in the transmission structure and transmitting the angular displacement to the controller 2, and the controller 2 obtains the displacement of the valve core according to the conversion rate of the angular displacement of the part into the angular displacement of the valve core.

As a preferred embodiment, the transmission structure comprises a rack 3 and a reduction gear set, one end of the rack 3 is connected with a floating connection structure 4, the other end of the rack 3 is meshed with the last stage of gear in the reduction gear set, the first stage of gear in the reduction gear set is meshed with the motor 1, the reduction gear set is used for conducting output of the motor 1 to the rack 3 after reducing and increasing torque, driving the rack 3 to move along the length direction of the rack 3, the rack 3 is connected with the floating connection structure 4 as a displacement output mechanism, and accordingly the rack 3 drives the valve core to extend or retract along the length direction of the rack 3 through the floating connection structure 4 so as to control on-off of an internal liquid path of a valve body connected with the motor driving actuator.

As a preferred embodiment, since the motor-driven actuator of the present application can ensure the displacement accuracy of the valve core through the rotary encoder and amplify the torque through the reduction gear set, the type selection requirement of the motor 1 is reduced, so that the present application can replace the conventionally adopted stepping motor with a relatively economical and applicable brushless motor, thereby reducing the product cost, and it should be noted that, based on the above technical scheme of the present application, it is conceivable that the torque of the motor 1 is amplified through other reduction mechanisms by those skilled in the art, which all belong to the protection scope of the present invention.

As a preferred embodiment, the motor-driven actuator may further include a housing 7, the housing 7 being formed with a rack guide chamber 8 and a floating connection structure guide chamber 9, the rack 3 being disposed in the rack guide chamber 8, the floating connection structure 4 being disposed in the floating connection structure guide chamber 9, the reduction gear set being capable of driving the rack 3 to move along the rack guide chamber 8, the rack 3 being capable of driving the floating connection structure 4 to move along the floating connection structure guide chamber 9, a chamber wall of the rack guide chamber 8 being engaged with a surface of the rack 3, a chamber wall of the floating connection structure guide chamber 9 being engaged with a surface of the floating connection structure 4, such that movement of the rack 3 and the floating connection structure 4 during extension and retraction is more stable.

As a specific embodiment, the motor-driven actuator may further include a housing 7, a stop member is formed on a final gear of the reduction gear set, a stop member corresponding to the stop member is formed on the housing 7, the motor 1 can drive the reduction gear set to rotate, the rack 3 can move from a first position to a second position under the driving of the motor 1, the stop member is limited by the stop member in a state in which the rack 3 is in the first position, and one end of the rack 3 far away from the floating connection structure 4 abuts against the housing 7 in a state in which the rack 3 is in the second position, so that a stroke is set for the motor-driven actuator by a mechanical structure, the first position and the second position of the rack 3 are a fully extended position and a fully retracted position of the rack 3, respectively, and a distance between the first position and the second position is a maximum stroke of the motor-driven actuator.

As a specific embodiment, the rotary encoder 5 is arranged at the last stage of reduction gears in the reduction gear set, the rotary encoder 5 can acquire the angular displacement of the last stage of reduction gears and feed back to the controller 2, as shown in fig. 1, the rotary encoder 5 is arranged at the third stage of reduction gears 12, the rotary encoder 5 can acquire the angular displacement of the third stage of reduction gears 12 and feed back to the controller 2, the controller 2 acquires the displacement of the rack 3 according to the angular displacement of the third stage of reduction gears 12, so as to acquire the displacement of the valve core, and the rotary encoder 5 is arranged at the last stage of reduction gears and can acquire more accurate data, so that the influence of mechanical gaps between the reduction gears is avoided, and the valve core displacement data acquired by the controller 2 through the rotary encoder 5 are more accurate.

As shown in fig. 1, the present invention provides a preferred motor-driven actuator comprising a brushless motor, a controller 2 for controlling the brushless motor, a floating universal joint for connecting a valve cartridge, a rack 3 connected to the floating universal joint, a three-stage reduction gear set for reducing the power output from the brushless motor to the rack 3, an electro-optical encoder mounted on a third-stage reduction gear 12, an interface 6 and a housing 7, the electro-optical encoder being electrically connected to the controller 2, one end of the joint 6 being electrically connected to the controller 2, the other end of the interface 6 being electrically connected to an external circuit, the housing 7 being formed with a rack guide chamber 8 and a floating joint guide chamber 9, corresponding software being downloaded to the controller 2 through the interface 6 before the motor-driven actuator is mounted, whereby the motor-driven actuator can be adjusted for parameters according to different use conditions, and the suitability of the motor-driven actuator is better, the opposite end of the floating joint 4 being connected to the valve cartridge 3 when the motor-driven actuator is mounted, since the motor-driven actuator is connected to the controller 2 through the floating joint 4, one end of the floating joint 4 being electrically connected to the controller, the movement of the valve cartridge being prevented from being displaced by a small gap between the rack 3 and the rack 3, and the mechanical displacement of the valve cartridge being further required by the mechanical reduction gear set, the mechanical reduction gear set being required to be mounted by the three-stage reduction gear set, the mechanical reduction gear set being reduced by the movement of the valve cartridge and the movement of the valve body, the valve body being displaced, and the displacement of the valve-driven actuator being displaced by the mechanical displacement is required to be reduced by the mechanical displacement, the valve mechanism, the valve-stage is required to be mounted, the displacement accuracy of the motor driving actuator is improved. After the valve core is installed, the floating connecting structure 4 and the rack 3 are respectively inserted into the motor driving actuator along the floating connecting structure guiding cavity 9 and the rack guiding cavity 8, the rack 3 and the third-stage decelerating paper wheel 12 are meshed, when the motor driving actuator is not electrified, the brushless motor is in a releasing state, the valve core is balanced with the middle-position accessory under the action of the spring force of the spring in the spring cavity, the brushless motor automatically resets after the power-on, the zero calibration can be automatically carried out by inputting a control signal, namely, the brushless motor is controlled to rotate forward or reversely, the valve core is driven to move by the third-stage decelerating gear set, the rack 3 and the floating connecting structure 4 until the valve core is limited by one side cavity wall of the valve cavity, the position value at the moment is acquired and recorded by the photoelectric encoder, the brushless motor is controlled to rotate reversely until the valve core is limited by the opposite side cavity wall of the valve cavity, the position value at the moment is acquired and recorded by the photoelectric encoder, the motor-driven actuator of the invention realizes zero automatic calibration through software, mechanical limit and photoelectric encoder, the motor-driven actuator can set new zero according to practical situation, the zero of the valve core is not required to be manually calibrated during installation, the suitability of the motor-driven actuator is further improved, the installation difficulty is reduced, the motor-driven actuator can be connected with an external controller through an interface 6, an operator can give out corresponding handle control signals through an operation handle, the external controller sends out corresponding control signals after receiving the corresponding control signals, the motor-driven actuator acts on the controller 2 in the motor-driven actuator, the controller 2 mainly comprises a control circuit and a drive circuit, the control circuit can convert the control signal into a motor control signal, the driving circuit outputs a control current according to the motor control signal to control the brushless motor to rotate forwards or backwards, the rotation angle and the rotation direction are determined by the motor control signal, the power output by the brushless motor is transmitted to the rack 3 after being decelerated by the three-stage reduction gear set, the rack 3 is meshed with the third-stage reduction gear 12, thereby converting the angular displacement of the gear into the extension or retraction displacement of the rack 3, the rack 3 drives the valve core to extend or retract through the floating connecting structure 4, the rack 3 and the floating connecting structure guide cavity 9 are formed on the shell of the motor driving actuator, so that the movement of the rack 3 and the floating connecting structure 4 is more stable, the displacement of the valve core is more stable and accurate, the kinetic energy of the motor 1 is transmitted to the rack 3 through the three-stage reduction gear set, the torque requirement of the motor-driven actuator on the motor 1 is reduced, meanwhile, the photoelectric encoder of the embodiment can collect the angular displacement of the third-stage reduction gear 12 and transmit the data to the controller 2, the controller 2 further controls the motor 1 to rotate by comparing the obtained actual angular displacement with the received expected angular displacement, ensures that the actual angular displacement is equal to the expected angular displacement, and ensures that the valve core displacement is equal to the expected displacement, and further, under the condition of higher control precision of displacement, the motor 1 of the embodiment adopts a brushless motor, thereby greatly reducing the production cost, and on the basis of the technical scheme of the application, the motor-driven actuator can also comprise various sensors which are used for collecting the data inside the motor-driven actuator, these sensors may be electrically connected to the controller 2 so that the collected internal data of the motor-driven actuator is transmitted to the external controller through the controller 2, and the communication modes between the motor-driven actuator and the external device are various, as shown in fig. 2, in this embodiment, the interface 6 is connected to the external controller through a CAN bus, the data is transmitted through a CAN signal, and a wireless communication module may be integrated in the controller 2, through which the interface 6 is used only to adjust parameters.

On the basis of the motor-driven actuator mentioned in the technical scheme, the invention further provides an electric control valve, the electric control valve comprises any one of the motor-driven actuators, parameters of the motor-driven actuator of the electric control valve can be adjusted to adapt to various working conditions, the suitability is good, the displacement of the valve core is ensured to be equal to expected displacement through the photoelectric encoder, the displacement control precision is high, in addition, the motor-driven actuator is connected with the valve core through a floating connection structure, the installation is convenient, the valve core is protected, and the service life of the electric control valve is prolonged.

From the above description, the invention has the advantages that the actual displacement of the valve core is obtained by the rotary encoder and fed back to the controller to control the motor, and the displacement control precision is higher; secondly, an interface is arranged, so that the program of the controller can be conveniently adjusted, and the motor driving actuator can adapt to various working conditions; thirdly, the motor driving actuator is connected with the valve core through the floating connection structure, so that the installation is convenient, the valve core and the rack are protected, and the service life is prolonged; fourth, the joint gap of the floating connection structure is compensated through software, so that the displacement control precision is further improved; fifth, the speed of the motor is reduced through the reduction gear set, and the control precision is ensured through the rotary encoder, so that a brushless motor can be used for replacing a conventional stepping motor, the cost is reduced, and the response speed is improved; sixth, can realize zero calibration through mechanical limit, software statement and rotary encoder, further reduce the installation degree of difficulty.

The preferred embodiments of the present invention have been described in detail above with reference to the accompanying drawings, but the present invention is not limited to the specific details of the above embodiments, and various simple modifications can be made to the technical solution of the present invention within the scope of the technical concept of the present invention, and all the simple modifications belong to the protection scope of the present invention.

In addition, the specific features described in the above embodiments may be combined in any suitable manner without contradiction. The various possible combinations of the invention are not described in detail in order to avoid unnecessary repetition.

Moreover, any combination of the various embodiments of the invention can be made without departing from the spirit of the invention, which should also be considered as disclosed herein.

Claims (10)

1. The motor-driven actuator is characterized by comprising a motor (1), a controller (2) for controlling the motor (1), a floating connection structure (4) for connecting a valve core, a transmission structure for transmitting power output by the motor (1) to the floating connection structure (4), a rotary encoder (5) and an interface (6), wherein one end of the interface (6) is electrically connected with the controller (2), the other end of the interface (6) is electrically connected with an external circuit, the output end of the rotary encoder (5) is connected with the controller (2), the controller (2) can acquire the displacement of the valve core through the rotary encoder (5), and the controller (2) can control the motor (1) through comparing the displacement of the valve core with the expected displacement of the valve core so that the displacement of the valve core is equal to the expected displacement of the valve core.

2. Motor driven actuator according to claim 1, characterized in that the controller (2) is capable of controlling the motor (1) to compensate for joint play of the floating connection (4).

3. The motor-driven actuator according to claim 1, wherein the controller (2) is capable of controlling the motor (1) to move the spool to a zero position.

4. Motor driven actuator according to claim 1, wherein the rotary encoder (5) is a photoelectric encoder.

5. The motor-driven actuator according to claim 1, wherein the transmission structure includes a rack (3) and a reduction gear set, one end of the rack (3) is connected to the floating connection structure (4), the other end of the rack (3) is meshed with a last stage gear of the reduction gear set, and a first stage gear of the reduction gear set is meshed with the motor (1).

6. Motor driven actuator according to claim 5, characterized in that the motor (1) is a brushless motor.

7. The motor-driven actuator according to claim 5, further comprising a housing (7), wherein the housing (7) is formed with a rack guide chamber (8) and a floating connection structure guide chamber (9), the rack (3) is disposed in the rack guide chamber (8), the floating connection structure (4) is disposed in the floating connection structure guide chamber (9), the reduction gear set is capable of driving the rack (3) to move along the rack guide chamber (8) under the driving of the motor (1), and the rack (3) is capable of driving the floating connection structure (4) to move along the floating connection structure guide chamber (9).

8. The motor-driven actuator according to claim 5, further comprising a housing (7), wherein a stopper is formed on a final gear of the reduction gear set, a stopper corresponding to the stopper is formed on the housing (7), the rack (3) is movable from a first position to a second position under the drive of the motor (1), the stopper is limited by the stopper in a state in which the rack (3) is in the first position, and an end of the rack (3) away from the floating connection structure (4) abuts against the housing (7) in a state in which the rack (3) is in the second position.

9. The motor-driven actuator according to claim 5, wherein the rotary encoder (5) is provided at a last stage reduction gear of the reduction gear set, and the rotary encoder (5) is capable of acquiring an angular displacement of the last stage reduction gear and feeding back to the controller (2).

10. An electrically controlled valve comprising the motor driven actuator of any one of claims 1-9.