Novel intelligent electric push rod

Abstract

The present invention relates to the technical field of electric push rods. Disclosed is a novel intelligent electric push rod, specifically comprising an alternating-current permanent magnet motor and a push rod driven thereby. The alternating-current permanent magnet motor is provided with Hall sensors for detecting the position of a rotor of the alternating-current permanent magnet motor; and the electric push rod comprises at least one of an electromagnetic brake control unit, a wireless communication or wired communication unit, a power-off compensation braking unit, and a push rod stroke position detection unit. The electromagnetic brake control unit in the present invention achieves, in an electromagnetic brake manner, holding and braking of the push rod when current flows through windings of the alternating-current permanent magnet motor, thereby solving the problem of a self-locking failure caused by the reduction of a friction coefficient of a screw pair; additionally, the push rod stroke position detection unit achieves detection of the upper (lower) limit position of the push rod stroke, thereby avoiding the problems caused by a mechanical limit switch, and effectively improving the service life of a product; and the wireless communication or wired communication unit in the present solution can reduce the number of wire harnesses, thereby simplifying an assembly and wiring mode and a maintenance process.

Description

A new intelligent electric push rod TECHNICAL FIELD

[0001] The present application belongs to the technical field of electric push rod, in particular to a new intelligent electric push rod. BACKGROUND

[0002] Electric push rod (electric push rod) is a kind of mechanical drive device that converts the rotary motion of electric motor into the linear reciprocating motion of push rod, mainly composed of motor, push rod and control device and other mechanisms. Considering the factors of comprehensive cost, efficiency, applicable environment and range, etc., more and more mechanical hands, hydraulic valves and pneumatic valves in various occasions can be replaced by electric push rod.

[0003] At present, the driving motor of electric push rod (electric push rod) mostly adopts brushless DC motor without rotor position signal, and through the on-off of two mechanical contact type micro-limit switches built in the threaded push rod sleeve and the change of the polarity of the power supply provided by the diode, the stop, extension, retraction control and stroke limit position stop protection control of the linear motion of electric push rod are realized. At the same time, the friction force between the threaded screw with trapezoidal self-locking thread and the nut contact surface overcomes the sliding force to realize stop self-locking and keep the stable position under load. In order to better realize the target stroke position control of electric push rod, it is usually necessary to combine with two external photoelectric or Hall position sensors S nF and S nR to detect the position signal to determine whether the push rod reaches the target set stop position of extension and retraction. In addition, in the cluster system of multi-push rod application, the parallel control mode shown in Figure 1 is mostly used, which at least needs one programmable controller PLC and N (N≥1) electric push rods, 2N relays (or N blocks of reversing controllers) and 2N sensors (S nF , S nR ) are composed, and each electric push rod is independently connected to the electric control cabinet.

[0004] The above electric push rod is affected by its own structure or working mode, which has the following problems:

[0005] 1. The electric push rod based on brushless DC motor has brush and mechanical copper sheet type commutator, and mechanical contact type micro-limit switch and other easily worn mechanical parts. In actual application, the electric push rod will have high product failure rate and short service life due to factors such as commutation spark, mechanical wear, forced current off and mechanical contact arc damage.

[0006] 2. Electric push rod exists self-locking failure problem. The existing most electric push rod brake self-locking mode is to rely on the friction force between the screw rod with trapezoidal self-locking screw thread and nut to realize self-locking. Usually, the electric push rod will be in failure due to the decrease of friction coefficient of screw pair caused by mechanical wear and the decrease of self-locking force after about 20,000 times of use.

[0007] 3. In the cluster system in the application of multiple push rods, too many host computer connection ports, host computer communication connection wires and certain volume of electric control cabinet are needed in the parallel communication connection mode, which increases the use cost and maintenance cost of the product for the client.

[0008] SUMMARY

[0009] The purpose of the present application is to provide a new intelligent electric push rod to solve the problems in the background art.

[0010] To achieve the above purpose, the technical scheme adopted by the present application is as follows: a new intelligent electric push rod, comprising an alternating current permanent magnet motor and a push rod, the alternating current permanent magnet motor is used to drive and control the push rod to work or stop, a Hall sensor for detecting the position of the rotor of the alternating current permanent magnet motor is arranged on the alternating current permanent magnet motor.

[0011] The electric push rod has at least one of an electromagnetic brake control unit, a communication unit, a power-off compensation brake unit and a push rod stroke position detection unit.

[0012] The electromagnetic brake control unit realizes the brake of the push rod when the alternating current permanent magnet motor is powered on in the form of electromagnetic brake.

[0013] The power-off compensation brake unit is used for the brake of the push rod when the alternating current permanent magnet motor is powered off.

[0014] The communication unit can realize information communication with the host computer in the form of wireless communication or wired communication.

[0015] The push rod stroke position detection unit comprises a nut with a magnetic unit and a non-contact Hall sensor stroke detection unit, the non-contact Hall sensor stroke detection unit is used to sense the position of the nut with the magnetic unit to realize the detection of the stroke position of the push rod.

[0016] Further comprising a controller, the controller is provided with a control circuit, the controller is used to control the start, operation, stop, brake or brake of the push rod.

[0017] Preferably, a plurality of pairs of pole permanent magnets are arranged on the rotor of the alternating current permanent magnet motor, and the implementation logic of the electromagnetic brake mode comprises the following steps:

[0018] S1: determining a target rotor position locking angle of the AC permanent magnet motor stop;

[0019] S2: using the flux linkage vector generated by the rotor permanent magnet of the AC permanent magnet motor in the stator winding, generating a current vector in the three-phase winding according to the target rotor position locking angle, and forming a damping electromagnetic brake braking torque around the target rotor position locking angle determined in S1;

[0020] S3: when the rotor of the AC permanent magnet motor stops at the target rotor position locking angle, the electromagnetic brake braking torque in S2 is zero; once the rotor deviates from the target rotor position locking angle, a damping electromagnetic brake braking torque is generated by applying a three-phase current vector to resist the rotor from deviating from the target rotor position locking angle.

[0021] Preferably, the calculation formula of the electromagnetic brake braking torque of the AC permanent magnet motor is as follows:

[0022] In the formula: is the electromagnetic torque coefficient, ψ sPM is the peak value of the stator winding flux linkage vector, I s is the stator winding current amplitude, θ s is the target rotor position locking angle, θ r is the actual rotor position angle.

[0023] Preferably, the push rod comprises a lead screw, the nut with the magnetic unit is threadedly connected on the lead screw, and the non-contact Hall sensor stroke detection unit comprises three Hall sensors arranged on the push rod, and the three Hall sensors are respectively used for push rod stroke upper limit position detection, push rod stroke lower limit position detection, and push rod stroke error correction.

[0024] Preferably, the power-off compensation brake unit comprises any one of three modes of mechanical brake, bearing pre-tightening mode, and brake by utilizing cogging torque effect;

[0025] The alternating current permanent magnet motor is provided with a mechanical brake assembly to realize mechanical brake braking mode, the mechanical brake assembly comprises a brake shell, an axially limiting slot with one side opening is arranged in the brake shell, a locking iron core is slid in the axially limiting slot, an elastic element is arranged in the axially limiting slot to make the locking iron core extend out of the axially limiting slot, an electromagnet assembly is arranged on the brake shell to compress the elastic element and make the locking iron core retract into the axially limiting slot, an insertion slot / insertion tooth or a key slot / key is arranged on the end of the locking iron core extending out of the axially limiting slot, the end of the rotor shaft of the alternating current permanent magnet motor is provided with an insertion tooth / insertion slot or a key / key slot which is used to cooperate with the insertion slot / insertion tooth or the key slot / key, a progress limiting element for limiting the extension length of the locking iron core is arranged in the brake shell, so that the depth of the insertion tooth / insertion slot or the key / key slot when embedded in each other is controllable, and the mechanical brake assembly uses the same power supply as the alternating current permanent magnet motor.

[0026] The alternating current permanent magnet motor comprises an end cover, a motor shell and a bottom cover, an axial bearing accommodating slot is formed in each of the end cover and the bottom cover, an axial bearing is arranged in each of the two axial bearing accommodating slots, the inner ring of the axial bearing is sleeved and fixed on the rotor shaft of the alternating current permanent magnet motor, two limiting rings are fixed on the rotor shaft of the alternating current permanent magnet motor, each of the axial bearings is arranged between a limiting ring and an axial bearing accommodating slot, and the end face of the outer ring of each of the two axial bearings is in contact with the bottom of the axial bearing accommodating slot. The inner ring end face of one of the axial bearings away from the bottom of the axial bearing accommodating slot and the limiting ring are provided with a butterfly washer, and the pre-tightening force of the axial bearing is obtained by the extrusion of the butterfly washer on the inner ring of the axial bearing.

[0027] Preferably, when the winding of the alternating current permanent magnet motor has no current, the alternating current permanent magnet motor can realize the brake brake of the electric push rod through the cogging torque effect.

[0028] Preferably, the control circuit comprises a microcontroller, a PWM signal driving circuit, a three-phase full-bridge inverter circuit and an overcurrent, overvoltage and overtemperature protection circuit, the three-phase full-bridge inverter circuit comprises three upper bridge arm power switch tubes Q1, Q3 and Q5 and three lower bridge arm power switch tubes Q2, Q4 and Q6, the microcontroller can output six PWM signals, and the six PWM signals output six control signals with the same bridge arm anti-passing interlocking protection function after passing through the PWM driving circuit.

[0029] Preferably, the wired communication mode adopted by the electric push rod is the RS485 or CAN bus serial communication mode, the alternating current permanent magnet motor is connected with a power supply circuit, the communication circuit and the power supply circuit are connected with the control circuit through a one-to-many integrated wiring harness, and the circuit board where the control circuit is arranged is provided with an RS485 or CAN bus communication interface to realize the communication connection with the upper computer.

[0030] The electric push rod adopts a ZigBee wireless communication unit, and the AC permanent magnet motor replaces the wired communication mode by ZigBee.

[0031] Preferably, the push rod comprises a screw rod, and the screw rod adopts a threaded screw rod or a ball screw rod.

[0032] Preferably, the AC permanent magnet motor and the push rod are connected through a transmission gear set, and the calculation formula of the displacement d of the electric push rod controlled by each Hall state is as follows:

[0033] Wherein, p is the pole pair number of the AC permanent magnet motor, h is the lead of the screw rod, and k is the gear reduction ratio of the transmission gear set.

[0034] Preferably, the AC permanent magnet motor comprises an end cover, a motor shell and a bottom cover, the outer wall of the motor shell is provided with a connecting part one, the side peripheral wall of the end cover and the bottom cover is provided with a connecting part two matched with the connecting part one, the connecting part one and the connecting part two are connected through a connecting piece and make the end cover, the motor shell and the bottom cover fixed together, and the cross section of the connecting part one and the connecting part two is in the shape of ear type, square, circle, semicircle or triangle.

[0035] The present application has the following advantages: the AC permanent magnet motor is used to replace the brush DC motor and its commutator controller, which can fundamentally solve the problems of commutation spark, mechanical wear and noise of the brush, improve the service life and dynamic response speed of the electric push rod, and save the commutator and its installation control cabinet and connecting wires.

[0036] The Hall sensor of the non-contact Hall sensor stroke detection unit is used to replace the mechanical contact type micro-limit switch to detect the stroke position of the push rod, and fundamentally solve the problems of mechanical contact wear and electric arc burn of the mechanical contact type micro-limit switch.

[0037] In addition, through the cooperation of the Hall sensor at the upper and lower limit positions of the push rod stroke, the Hall sensor at the position of the motor inner rotor, the reduction ratio of the transmission gear set and the lead of the threaded screw rod, the three closed-loop control of the electric push force, the running speed and the stroke position of the electric push rod is realized, the control accuracy and the dynamic response speed of the electric push rod are improved, and the purpose of intelligent control of the electric push rod is achieved.

[0038] Meanwhile, under the action of the Hall sensor for push rod stroke error correction, the cumulative stroke error of the push rod caused by factors such as motor speed error, transmission error of the reduction gear set and screw pitch error can be eliminated or corrected, and the stroke accuracy and working reliability of the electric push rod are further ensured.

[0039] Wherein, the application solves the problem of self-locking failure caused by the decrease of friction coefficient of thread pair due to mechanical wear by using the flux linkage vector generated by the rotor permanent magnet of the AC permanent magnet motor in the stator winding to generate current vector in the three-phase winding according to the target rotor position locking angle, forming a brake torque with damping property around any rotor position locking angle, and the brake torque is zero when the rotor stops at the target rotor position locking angle, so that the electric push rod can be reliably self-locked and stopped.

[0040] Wherein, when the AC permanent magnet motor is powered on, the electric push rod realizes brake by the electromagnetic brake mode, at this time, the locking core in the mechanical brake assembly in the scheme is retracted into the axial limiting groove; when the AC permanent magnet motor is powered off, the electromagnetic brake in the scheme cannot be used, and the push rod can realize brake through the mechanical brake assembly or through the way of pre-tightening the bearing; the dual brake system combining the electromagnetic brake using the characteristics of the motor and the external mechanical brake assembly (or the way of pre-tightening the bearing) together forms the stopping brake self-locking force of the electric push rod, and completely solves the problem of self-locking failure caused by the decrease of friction coefficient of thread pair due to mechanical wear.

[0041] The dual self-locking brake mode is not only suitable for AC permanent magnet motor, but also suitable for permanent magnet synchronous motor and brushless DC motor electric push rod

[0042] In addition, the AC permanent magnet motor can also use the cogging torque effect to replace the above-mentioned mechanical brake assembly to realize the function of brake.

[0043] Wherein, when the application adopts RS485 or CAN bus wired communication, the communication line and power circuit are integrated in an integrated wiring harness, which simplifies the assembly wiring mode and maintenance process, and different leads can be distinguished by color, etc., to avoid accidental failure caused by signal lead wiring error; or wireless communication methods such as ZigBee are used to replace wired communication methods such as RS485 or CAN bus, which can further reduce the use of wiring harness;

[0044] Wherein, since the connecting structure of the end cover, the shell and the bottom cover is usually arranged in the shell of the alternating current permanent magnet motor, for example, in the alternating current permanent magnet motor, since the stator part is in the shape of a barrel, the shell of the motor needs to match the shape of the stator, and the connecting structure undoubtedly increases the overall volume of the alternating current permanent magnet motor, thereby causing the alternating current permanent magnet motor to have a large size; the external connecting structure in the shape of an ear, a square or other shapes is arranged on the external peripheral wall of the shell of the alternating current permanent magnet motor, the shell of the motor is changed from expanding the cavity volume to increasing the connecting structure on the external wall of the motor shell, so that the overall volume of the motor changes little, meanwhile, the connecting part two and the connecting part one on the end cover, the shell and the bottom cover are fixed together through the connecting piece, so that the firmness and stability of the connection between the end cover, the shell and the bottom cover are effectively ensured;

[0045] In addition, the innovation of the mechanical brake holding mode in the application can make the screw rod structure of the electric push rod break through the limitation of the traditional threaded screw rod, and use a ball screw rod with a small friction coefficient and a higher transmission efficiency. BRIEF DESCRIPTION OF DRAWINGS

[0046] Fig. 1 is a wiring schematic diagram of a multi-push rod cluster control system in the prior art using a parallel communication mode;

[0047] Fig. 2 is a connection schematic diagram between the electric push rod in the application and the upper computer using a wireless communication mode;

[0048] Fig. 3 is a control circuit principle block diagram when using wireless communication in the application;

[0049] Fig. 4 is a control circuit principle block diagram when using wired communication in the application;

[0050] Fig. 5 is a structure schematic diagram of the motor and the push rod when using wired communication in the application;

[0051] Fig. 6 is a structure schematic diagram of the motor and the push rod when using wireless communication in the application;

[0052] Fig. 7 is a connecting structure schematic diagram of the mechanical brake holding assembly and the alternating current permanent magnet motor in the application;

[0053] Fig. 8 is a structure schematic diagram of the mechanical brake holding assembly in the application;

[0054] Fig. 9 is an internal structure schematic diagram of the alternating current permanent magnet motor with bearing pre-tightening force in the application;

[0055] Fig. 10 is an enlarged schematic diagram of part A of Fig. 9;

[0056] Fig. 11 is a position schematic diagram of a non-contact Hall sensor stroke detection unit in the application;

[0057] Fig. 12 is a schematic diagram of the dependence of various units in the application on the electric push rod;

[0058] In the figure: 1, gate shell; 2, locking core; 3, electromagnet structure; 4, axial limiting groove; 5, elastic member; 6, progress limiting member; 7, rotor shaft of the alternating current permanent magnet motor; 8, mechanical brake holding assembly; 9, push rod; 10, motor housing; 11, end cover; 12, bottom cover; 13, connection part one; 14, connection part two; 15, connecting member; 16, integrated wiring harness; 17, placement cabin; 18, wireless communication module; 19, push rod housing; 20, stroke plate; 21, Hall sensor in the non-contact Hall sensor stroke detection unit; 22, nut; 23, magnetic unit; 24, bearing; 25, limiting ring; 26, butterfly gasket. DETAILED DESCRIPTION

[0059] The preferred embodiments of the application are described in detail below with reference to the accompanying drawings, so that the advantages and features of the application can be more easily understood by those skilled in the art, and the protection scope of the application can be more clearly and definitely defined.

[0060] Embodiment:

[0061] Referring to Fig. 12, the application discloses a new type of intelligent electric push rod, which comprises an alternating current permanent magnet motor and a push rod, the alternating current permanent magnet motor comprises an end cover 11, a motor housing 10 and a bottom cover 12, the push rod comprises a screw rod, the alternating current permanent magnet motor is used for driving and controlling the push rod to work or stop, three Hall sensors for detecting the position of the rotor of the alternating current permanent magnet motor are arranged on the alternating current permanent magnet motor, each Hall position sensor is sequentially different by 120 electrical angles, and is distributed in the alternating current permanent magnet motor in a circular array with the rotor shaft 7 of the alternating current permanent magnet motor as the center;

[0062] The electric push rod has at least one of an electromagnetic brake control unit, a communication unit, a power-off compensation brake unit and a push rod stroke position detection unit;

[0063] The electromagnetic brake control unit realizes the brake of the push rod when the alternating current permanent magnet motor is powered on in the form of electromagnetic brake holding;

[0064] The power-off compensation brake unit is used for the brake of the push rod when the alternating current permanent magnet motor is powered off;

[0065] The communication unit can realize information communication with the upper computer in the form of wireless communication or wired communication;

[0066] The push rod stroke position detection unit comprises a nut 22 with a magnetic unit 23 and a non-contact Hall sensor stroke detection unit, the non-contact Hall sensor stroke detection unit is used for sensing the position of the nut 22 with the magnetic unit 23, so as to realize the detection of the stroke position of the push rod.

[0067] The controller is further provided with a control circuit, and the controller is used for controlling the starting, running, stopping, braking or braking of the push rod.

[0068] The rotor of the alternating current permanent magnet motor is provided with a plurality of pairs of pole permanent magnets, and the implementation logic of the electromagnetic brake mode comprises the following steps:

[0069] S1: determining the target rotor position locking angle of the alternating current permanent magnet motor stop;

[0070] S2: using the flux linkage vector generated by the rotor permanent magnet of the alternating current permanent magnet motor in the stator winding, generating current vector in the three-phase winding according to the target rotor position locking angle, and forming electromagnetic brake damping torque around the target rotor position locking angle determined in S1;

[0071] S3: when the rotor of the alternating current permanent magnet motor stops at the target rotor position locking angle, the electromagnetic brake damping torque in S2 is zero; once the rotor deviates from the target rotor position locking angle, the electromagnetic brake damping torque with damping property is generated by applying three-phase current vector to resist the deviation of the rotor from the target rotor position locking angle.

[0072] The calculation formula of the electromagnetic brake damping torque of the alternating current permanent magnet motor is as follows:

[0073] In the formula: is the electromagnetic torque coefficient, ψ sPM is the peak value of the stator winding flux linkage vector, I s is the amplitude of the stator winding current, θ s is the target rotor position locking angle, θ r is the actual rotor position angle.

[0074] Among them, due to the stability of the electromagnetic brake, the screw rod of the electric push rod can be selected from the threaded screw rod with small friction coefficient and high transmission efficiency.

[0075] The control scheme of the alternating current permanent magnet motor includes starting control logic and running control logic; the starting control logic and running control logic of the alternating current permanent magnet motor can choose the following two ways:

[0076] (1) the starting control logic and running control logic both adopt SVPWM or SPWM control mode;

[0077] (2) the starting control adopts square wave control logic, and the running control adopts the mode of field oriented FOC control logic;

[0078] The alternating current permanent magnet motor adopts the electromagnetic brake mode to realize the brake braking of the motor, wherein a controller for controlling the starting, running, stopping or brake braking function of the push rod is arranged on the motor, a control circuit is arranged in the controller, the control circuit is arranged on a PCB board, the control circuit comprises a microcontroller, a PWM signal driving circuit and a three-phase full-bridge inverter circuit, three-phase PWM control instructions are sent through the PWM port of the microcontroller, and the PWM signal driving circuit controls the three-phase full-bridge inverter circuit to output three-phase voltage after conversion and conditioning of the control instructions.

[0079] Referring to FIG. 3 or FIG. 4, in the embodiment, the control circuit can be specifically arranged as follows: the microcontroller, the PWM signal driving circuit and the three-phase full-bridge inverter circuit are sequentially electrically connected, one end of the microcontroller is connected to a power supply, and the other end is grounded, the three-phase full-bridge inverter circuit comprises three upper bridge arm power switching tubes Q1, Q3 and Q5 and three lower bridge arm power switching tubes Q2, Q4 and Q6, the microcontroller can output six-way PWM signals, and the six-way PWM signals output control signals of six-way power switching tubes with the bridge arm anti-passing interlocking protection function after the driving circuit, wherein the power switching tube can be a MOSFET, an IGBT or the like, taking the MOS tube as an example, the three-phase full-bridge inverter circuit comprises three P-MOSFET tubes Q1, Q3 and Q5 and three N-MOSFET tubes Q2, Q4 and Q6, the gates of the six MOSFET tubes are connected to the driving circuit of the PWM control signal, the sources of the three P-MOSFET tubes Q1, Q3 and Q5 are commonly connected to the power supply, the sources of the three N-MOSFET tubes Q2, Q4 and Q6 are commonly grounded, the drain of Q1 and the drain of Q4 are connected and commonly connected to a winding of the alternating current permanent magnet motor, the drain of Q3 and the drain of Q6 are connected and commonly connected to a winding of the alternating current permanent magnet motor, the drain of Q5 and the drain of Q2 are connected and commonly connected to a winding of the alternating current permanent magnet motor, in addition, a diode for freewheeling is connected in parallel between the source and the drain of each MOSFET tube, the anode of the diode connected in parallel on the P-MOSFET tube is connected to the drain of the MOSFET tube, the anode of the diode connected in parallel on the N-MOSFET tube is connected to the source of the MOSFET tube, in addition, functional circuits such as overcurrent, overvoltage and temperature detection can be connected in the control circuit to strengthen the protection of the control circuit, and the functional circuits such as overcurrent, overvoltage and temperature detection can refer to the specific arrangement mode of the Chinese patent with the application number CN2023116044969.

[0080] Taking an AC permanent magnet motor as an example, when the motor's start-up and operation logic both adopt SVPWM or SPWM, after the electric actuator receives work commands such as extension, retraction, and stop, the microcontroller of the electric actuator will control the 6-channel PWM output ports to issue corresponding SVPWM or SPWM control commands based on the received commands and the AC permanent magnet motor rotor position information detected by the Hall sensor. These control commands are then converted and conditioned by the PWM control signal drive circuit, outputting 6 control signals with anti-same-bridge-arm shoot-through interlock protection to control the 6 power switching transistors Q1 to Q6 of the three-phase full-bridge inverter circuit to turn on or off according to a certain conduction logic, thereby converting the 0 to +24V DC power supply voltage into U... A U B U C Three-phase alternating voltage is applied to the three-phase windings of the AC permanent magnet motor to control the start, stop, or rotation direction of the AC permanent magnet motor, thereby realizing closed-loop control of the current, speed, and position of the electric actuator until a new signal changing the operating state is received.

[0081] In the AC permanent magnet motor split-mode control scheme, the motor's starting logic uses square wave control, and the running logic uses FOC (Free-Order Control). At this time, the microcontroller, based on the rotor position signal detected by the three-phase rotor Hall position sensor and the power converter's conduction logic, outputs a PWM signal to control the six power switches Q1-Q6 of the three-phase bridge inverter circuit to turn on or off according to a specific conduction logic, achieving rapid start-up and converting the +24V DC power supply voltage to U... A U B U C A three-phase alternating voltage is applied to the three-phase windings of an AC permanent magnet motor.

[0082] When the starting speed of the AC permanent magnet motor reaches 8% to 15% of the rated speed, the controller will automatically switch to the FOC control logic with fast execution speed and torque response, and control the six power switching transistors Q1 to Q6 to conduct or turn off according to a certain conduction logic, thereby realizing the full speed-torque domain operation of the AC permanent magnet motor. This can improve the operating efficiency and dynamic response speed of the electric actuator, reduce torque pulsation, and avoid the disadvantages of vibration and noise caused by torque pulsation when the AC permanent magnet motor is running under square wave control logic.

[0083] The implementation logic of the electromagnetic brake in this scheme is deduced as follows. Taking an AC permanent magnet motor as an example, the electromagnetic brake method in this scheme utilizes the magnetic flux vector generated by the permanent magnet of the motor rotor on the stator winding, and the current vector I generated in the three-phase winding according to the target rotor position locking angle. s Forming around any rotor position (e.g.) The electromagnetic braking torque T, which has damping properties, is generated by a specific rotor position (such as electrical angle).h i.e. when the rotor is stopped at the target rotor position lock angle, the electromagnetic brake torque T h is zero; once the rotor deviates from the lock position, the electromagnetic brake torque of damping nature opposes the rotor deviation from the lock position, and no matter whether the rotor deviates counterclockwise or clockwise, an electromagnetic brake torque of damping nature opposing the rotor deviation from the target rotor position lock angle can be generated by an applied three-phase current vector. In the range of 90° electrical angle from the lock position, the farther the rotor deviates from the lock position, the greater the generated electric damping electromagnetic torque T h .

[0084] Specifically: if the phase currents i A , i B , i C of the three-phase winding generating the damping torque are respectively:

[0085] then the electromagnetic brake torque is:

[0086] Suppose that the rotor is to be locked at the position of when the AC permanent magnet motor is braked to stop, according to the electromagnetic brake torque T h formula, as long as an electric current vector capable of generating a damping torque is applied in the three-phase winding, the actual rotor position angle θ r of the AC permanent magnet motor always tracks the target position lock angle θ s , i.e. when the electromagnetic brake torque T h = 0, the AC permanent magnet motor stops rotating, and thus the rotor is locked at the target rotor position lock angle of .

[0087] Specifically, suppose that the electric push rod is extended forward, and the AC permanent magnet motor is in positive rotation, at this time the positive torque is greater than 0. In the interval of , the phases of the current are (i A <0, i B <0, i C > 0), to make the AC permanent magnet motor brake and lock at the rotor position of , an electric current (i A , i B , i C ) capable of generating a brake torque needs to be applied to the AC permanent magnet motor:

[0088] As long as the rotor position is in the interval of Within this range, the aforementioned current will force the rotor of the AC permanent magnet motor to return to its original position. Position and lock, and generate electromagnetic brake torque.

[0089] Similarly, if the electric actuator retracts inward, the AC permanent magnet motor rotates in the opposite direction, and the reverse torque is less than 0. Within the interval, the phase of the current is (i A >0,i B >0,i C <0), to lock the rotor of an AC permanent magnet motor At this position, a current vector (i) that can generate the braking torque of the holding brake needs to be applied. A i B i C This forces the rotor to rotate in the opposite direction. The target locking angle at the location. Among them,

[0090] Similarly, if the target locking angle of the AC permanent magnet motor rotor is... The position, the applied three-phase current (i A i B i C ) should be The electromagnetic brake torque Th is equal to 0.

[0091] According to the electromagnetic brake torque formula above, when the AC permanent magnet motor speed is zero, the three Hall effect signals remain unchanged. If the three Hall effect signals change, it indicates that the AC permanent magnet motor is rotating. The three-phase current then applies a PWM closed-loop current control signal with rated constant amplitude in a specific logical sequence, controlling the AC permanent magnet motor rotor to lock at the target rotor position locking angle, thereby achieving electromagnetic brake braking. Furthermore, the greater the rotor angle is from the target locking angle, the greater the required pulling force, the greater the impedance torque, and the greater the current. By applying this characteristic to the electric actuator, it helps to form the self-locking mechanism of the electric actuator, solving the self-locking failure problem mentioned in the background technology.

[0092] Referring to Figures 7, 8, 9, and 10, the power failure compensation brake unit includes any one of three braking methods: mechanical brake braking (or preload on the bearing, or use of cogging torque effect).

[0093] The alternating current permanent magnet motor is provided with a mechanical brake assembly 8 to realize mechanical brake braking mode, the mechanical brake assembly comprises a brake shell 1, an axially limiting slot 4 with one side opening is arranged in the brake shell, a locking iron core 2 is slid in the axially limiting slot 4, an elastic element 5 is arranged in the axially limiting slot 4 to make the locking iron core 2 extend out of the axially limiting slot 4, an electromagnet assembly 3 is arranged on the brake shell to compress the elastic element 5 and make the locking iron core 2 retract into the axially limiting slot 4, a slot / tooth or key slot / key is arranged on the end of the locking iron core 2 extending out of the axially limiting slot 4, the end of the rotor shaft 7 of the alternating current permanent magnet motor is provided with a tooth / slot or key / key slot used for matching the slot / tooth or key slot / key, a progress limiting element 6 for limiting the extension length of the locking iron core is arranged in the brake shell to ensure that the depth of the tooth / slot or key / key slot when embedded in each other is controllable, the mechanical brake assembly uses the same power supply as the alternating current permanent magnet motor;

[0094] The end cover 11 and the bottom cover 12 of the alternating current permanent magnet motor are each provided with a bearing accommodating slot, and each of the two bearing accommodating slots is provided with a bearing 24, the inner ring of the bearing 24 is sleeved and fixed on the rotor shaft 7 of the alternating current permanent magnet motor, and the rotor shaft 7 of the alternating current permanent magnet motor is further fixed with two limiting rings 25, each of the bearings is arranged between a limiting ring 25 and a bearing accommodating slot, and the end face of the outer ring of each of the two bearings 24 is in contact with the bottom of the bearing accommodating slot, and a butterfly gasket 26 is arranged between the inner ring end face of the bearing 24 away from the bottom of the bearing accommodating slot and the limiting ring 25, and the pre-tightening force of the bearing is obtained through the extrusion of the butterfly gasket 26 on the inner ring of the bearing.

[0095] In addition, the electric push rod can realize brake braking through the cogging torque effect, for example, the cogging torque effect of the alternating current permanent magnet motor with 9 slots and 12 poles or other specific reluctance matching can be used to replace the above-mentioned mechanical brake braking mode or the mode of pre-tightening the bearing to realize the function of brake braking, and it should be noted that only the motor capable of utilizing the cogging torque effect can replace the mechanical brake braking mode or the mode of pre-tightening the bearing to realize brake braking.

[0096] The outer wall of the motor housing is provided with a connecting part one 13, the side peripheral wall of the end cover 11 and the bottom cover 12 is provided with a connecting part two 14 matched with the connecting part one 13, the connecting part one 13 and the connecting part two 14 are connected through a connecting piece 15 and the end cover 11, the motor housing 10 and the bottom cover 12 are fixed together, the cross section of the connecting part one 13 and the connecting part two 14 is in the form of lug, square, circle, semicircle or triangle, the connecting piece can be a long bolt, the AC permanent magnet motor main body, the driving controller, the communication unit and the rotor position Hall sensor are integrated and fixed together, the PCB board provided with the control circuit can be placed and fixed on the stator slot frame (the stator slot frame is the conventional structure of the existing motor) at the front end or the rear end of the AC permanent magnet motor, and the three Hall position sensors are uniformly distributed on the circumference with the rotor as the center.

[0097] Benefiting from the action of the Hall sensor, 6 key position signals in each 360° electric angle of the AC permanent magnet motor can be transmitted to the microcontroller according to the rotor position Hall sensor detection, the microcontroller will realize the closed loop control of the extension stroke position of the threaded push rod according to the rotor position signal, and accurately and protectively control the stroke limit position of the threaded push rod, so as to realize the closed loop control of the straight walking position or the displacement amount of the electric push rod.

[0098] In the embodiment, the rotor Hall position sensor transmits the rotor position information of the AC permanent magnet motor to the microcontroller, the microcontroller will control the extension stroke of the electric push rod according to the position information and the gear reduction ratio of the transmission gear set and the lead of the threaded screw rod, so as to realize the accurate control of the stroke position of the electric push rod and the high-precision closed loop control of the displacement amount, for example, assuming that the motor drives the push rod through a three-stage transmission gear set, the transmission gear set reduction ratio k=k1k2k3 (k i The number of pole pairs of the AC permanent magnet motor is p, and the lead of the screw rod is h, so that the displacement amount d of the electric push rod controlled by the AC permanent magnet motor rotor position corresponding to each Hall state is:

[0099] Through the above formula, assuming that the AC permanent magnet motor of the electric push rod adopts 9-slot 10-pole or 9-slot 12-pole, the pole pair number p=5 or 6. Taking p=5 as an example, the gear reduction ratio k of the transmission gear set is 20.45, the lead h of the screw rod is 3.175 mm, and the displacement amount of the electric push rod walking controlled by the Hall state changed each time is:

[0100] Through the above design, the position and speed of the motor rotor can be measured according to the state of the Hall sensor of the reaction rotor position information, the stroke position and required speed of the push rod are calculated, the output signal of the three-phase SVPWM is controlled, the three-phase voltage output by the three-phase full-bridge inverter circuit is adjusted, and the torque, speed and position of the alternating current permanent magnet motor are controlled, that is, the speed closed-loop control and high-precision position closed-loop control of the electric push rod are realized, so that the application can be applied to more high-precision occasions.

[0101] The non-contact Hall sensor stroke detection unit is arranged on the push rod, and the nut with the magnetic unit is threadedly connected to the screw rod; the non-contact detection unit is used for inducting the magnetic unit carried by the nut to realize detection of the stroke position of the push rod extending or retracting.

[0102] The non-contact Hall sensor stroke detection unit includes three Hall sensors respectively used for push rod stroke upper limit position detection, push rod stroke lower limit position detection and push rod stroke error correction.

[0103] Specifically, by setting the sensor sensing range parameters, the Hall sensors for detecting the upper and lower limit positions of the push rod stroke can send a stop signal when the push rod reaches the target stroke position, or can send a stop signal when the push rod reaches the upper (lower) limit position of the push rod stroke (i.e. over extension or contraction).

[0104] Two Hall sensors can be arranged on the push rod, one Hall sensor is used for simultaneous detection of the target stroke position in the push rod retraction process and the lower limit position of the push rod stroke, and the other Hall sensor is used for simultaneous detection of the target position in the push rod extension process and the upper limit position of the push rod stroke; for example, two values (such as the position of the magnetic unit entering the sensing range and the position of the magnetic unit leaving the sensing range) can be selected according to the sensing range of the sensor, which represent the target stroke position and the upper (lower) limit position of the push rod extension (retraction), so that the target stroke position of the push rod and the upper (lower) limit position of the push rod can be detected simultaneously.

[0105] Meanwhile, the target stroke detection unit (such as the photoelectric sensor mentioned in the background art) in the existing electric push rod technology can also be used in cooperation with the two Hall sensors to realize the target stroke monitoring of the push rod extending or retracting and the upper (lower) limit position monitoring of the push rod stroke.

[0106] Since the displacement d of the electric push rod can be controlled by each Hall state, the target stroke of the electric push rod can also be calculated and determined, that is, whether the push rod reaches the target stroke position can be detected and controlled by detecting the change of the rotor Hall state, and the upper (lower) limit position of the push rod stroke can be detected and controlled by cooperating with the Hall sensor in the non-contact stroke detection unit.

[0107] Referring to FIG. 11, the present embodiment takes the non-contact stroke detection unit for detecting the upper and lower limit positions of the push rod stroke as an example, at this time, the Hall sensor plays the role of replacing the mechanical contact micro switch to realize the detection of the stroke position of the push rod;

[0108] Wherein, the push rod comprises a push rod shell 19, a stroke plate 20 is arranged on the push rod shell, the Hall sensor 21 in the non-contact Hall sensor stroke detection unit can be welded on the stroke plate 20, and then integrally fixed on any side in the cavity of the push rod shell 19, or arranged outside the push rod shell 19 in the form of an independent sensor. When the electric push rod abnormally, for example, after extending (or retracting) to the target position, it does not perform the corresponding action according to the set instruction, but continues to extend outward (or retract inward) after passing the target position, at this time, the nut 22 with the magnetic unit 23 reaches the sensing range of the non-contact Hall sensor stroke detection unit, the Hall sensor 21 detects the position information and transmits it to the microcontroller for comparison with the preset limit position threshold, and the microcontroller will issue a control instruction to control or adjust the running state of the electric push rod according to the comparison result, so as to avoid over-extension and contraction failure.

[0109] The magnetic unit on the nut can be a magnet or a magnetic steel. The size, shape and position of the magnetic steel on the nut can be, but are not limited to, as shown in FIG. 9, which can also be circular or annular.

[0110] In addition, referring to FIG. 2, the push rod realizes information communication with the upper computer in a wireless communication or wired communication mode, and the motor is connected to the power supply circuit for power supply;

[0111] Referring to FIG. 5, the wired communication mode adopted by the electric push rod is RS485 or CAN bus serial communication mode, the communication line and the power supply circuit adopt a one-to-many integrated wiring harness 16 connected with the control circuit, and the control circuit is provided with an RS485 or CAN bus communication interface on the circuit board to realize the communication connection with the upper computer.

[0112] Referring to FIG. 6, the wireless communication mode adopted by the electric push rod is ZigBee, at this time, the alternating current permanent magnet motor replaces the wired communication line by ZigBee, and the ZigBee wireless communication module is electrically connected with the control circuit;

[0113] Wherein, the wireless communication module in the present scheme includes but is not limited to Zigbee, Bluetooth BLE, Wi-Fi and other wireless connection modes, and the wired connection mode includes but is not limited to RS485 / CAN bus serial communication connection mode.

[0114] Among them, referring to Figure 6, the end cover and the bottom cover of the alternating current permanent magnet motor are provided with O-shaped sealing rings to improve the sealing level of the alternating current permanent magnet motor, the controller is installed at the front end inside the cavity of the alternating current permanent magnet motor shell, the rear end cover of the alternating current permanent magnet motor is externally provided with a placement cabin 17, the placement cabin is provided with an opening for accommodating the ZigBee, Bluetooth BLE, Wi-Fi and other wireless communication modules 18, and the opening is detachably connected with a sealing cover. The connecting line between the controller and the wireless communication module is routed along the inner wall of the alternating current permanent magnet motor shell close to the connecting portion; the bottom cover of the alternating current permanent magnet motor is provided with a wire outlet hole for connecting the alternating current permanent magnet motor drive controller (i.e. the PCB of the control circuit) with external limit switches, power supplies, upper computer group control (only wired communication is required) and other devices or equipment; two long screws pass through the double-ear through holes of the alternating current permanent magnet motor shell to assemble the alternating current permanent magnet motor end cover, the alternating current permanent magnet motor shell and the alternating current permanent magnet motor bottom cover with the wireless communication module cabin together, and the alternating current permanent magnet motor can be fixedly installed on the base of the electric push rod (the base of the electric push rod is a conventional structure of the electric push rod).

[0115] The above is only an embodiment of the present application, and does not limit the patent scope of the present application, and any equivalent structural transformation or direct or indirect application in other related technical fields based on the content of the specification and drawings of the present application is also included in the patent protection scope of the present application.

Claims

1. A new smart motorized push rod characterized in that: The electric push rod comprises an alternating current permanent magnet motor for driving the push rod to work or stop, and a push rod, wherein the alternating current permanent magnet motor is provided with a Hall sensor for detecting the position of the rotor of the alternating current permanent magnet motor; The electric push rod has at least one of an electromagnetic brake control unit, a communication unit, a power-off compensation brake unit and a push rod stroke position detection unit; The electromagnetic brake control unit adopts the electromagnetic brake mode to realize the brake of the push rod when the alternating current permanent magnet motor is powered on; The power-off compensation brake unit is used for the brake of the push rod when the alternating current permanent magnet motor is powered off; The communication unit can realize information communication with the upper computer in a wireless communication mode or a wired communication mode; The push rod stroke position detection unit comprises a nut (22) with a magnetic unit (23) and a non-contact Hall sensor stroke detection unit for sensing the position of the nut (22) with the magnetic unit (23) to realize the detection of the stroke position of the push rod; The controller is provided with a control circuit, and is used for controlling the start, operation, stop, brake or brake of the push rod.

2. A new smart motorized push rod according to claim 1 characterized in that: The rotor of the alternating current permanent magnet motor is provided with a plurality of pairs of pole permanent magnets, and the implementation logic of the electromagnetic brake mode comprises the following steps: S1: determining the target rotor position locking angle of the alternating current permanent magnet motor; S2: using the magnetic chain vector generated by the permanent magnet of the rotor of the alternating current permanent magnet motor in the stator winding, generating a current vector in the three-phase winding according to the target rotor position locking angle, and forming a damping electromagnetic brake torque around the target rotor position locking angle determined in S1; S3: when the rotor of the alternating current permanent magnet motor stops at the target rotor position locking angle, the electromagnetic brake torque in S2 is zero; once the rotor deviates from the target rotor position locking angle, the damping electromagnetic brake torque is generated by applying a three-phase current vector to resist the deviation of the rotor from the target rotor position locking angle.

3. A new smart motorized push rod according to claim 2, characterized in that: The formula for calculating the electromagnetic holding brake torque of the alternating current permanent magnet motor is as follows: In the formula: is the electromagnetic torque coefficient, ψ sPM is the stator winding flux linkage vector peak, I s is the stator winding current amplitude, θ s is the target rotor position lock angle, θ r is the actual rotor position angle.

4. A new smart motorized push rod according to claim 1 characterized in that: The non-contact Hall sensor stroke detection unit is arranged on the push rod, the push rod (9) comprises a lead screw, the nut (22) with the magnetic unit (23) is threadedly connected to the lead screw, the non-contact Hall sensor stroke detection unit comprises three Hall sensors (21) arranged on the push rod, and the three Hall sensors (21) are respectively used for push rod stroke upper limit position detection, push rod stroke lower limit position detection and push rod stroke error correction.

5. A new smart electric trolley according to claim 1 characterized in that: The power-off compensation brake unit comprises any one of three modes of mechanical brake, pre-tightening of the bearing or brake or brake by using the cogging torque effect. The alternating current permanent magnet motor is provided with a mechanical brake assembly (8) to realize mechanical brake braking mode, the mechanical brake assembly comprises a brake shell (1), an axially limiting slot (4) with one-side opening is arranged in the brake shell, a locking iron core (2) is slid in the axially limiting slot (4), an elastic element (5) is arranged in the axially limiting slot (4) to make the locking iron core (2) extend out of the axially limiting slot (4), an electromagnet assembly (3) is arranged on the brake shell to compress the elastic element (5) and make the locking iron core (2) retract into the axially limiting slot (4), a slot / tooth or a key slot / key is arranged on the end of the locking iron core (2) extending out of the axially limiting slot (4), the end of a rotor shaft (7) of the alternating current permanent magnet motor is provided with a tooth / slot or a key / key slot used for matching the slot / tooth or the key / key slot, a progress limiting element (6) for limiting the extension length of the locking iron core is arranged in the brake shell, so that the depth of the tooth / slot or the key / key slot when embedded in each other is controllable, the mechanical brake assembly uses the same power supply as the alternating current permanent magnet motor; The alternating current permanent magnet motor comprises an end cover (11), a motor shell (10) and a bottom cover (12), an axially limiting slot (4) with one-side opening is arranged in the brake shell, an axially limiting slot (4) with one-side opening is arranged in the brake shell, an axially limiting slot (4) with one-side opening is arranged in the brake shell, an axially limiting slot (4) with one-side opening is arranged in the brake shell, an axially limiting slot (4) with one-side opening is arranged in the brake shell, an axially limiting slot (4) with one-side opening is arranged in the brake shell, an axially limiting slot (4) with one-side opening is arranged in the brake shell, an axially limiting slot (4) with one-side opening is arranged in the brake shell, an axially limiting slot (4) with one-side opening is arranged in the brake shell, an axially limiting slot (4) with one-side opening is arranged in the brake shell, an axially limiting slot (4) with one-side opening is arranged in the brake shell, an axially limiting slot (4) with one-side opening is arranged in the brake shell, an axially limiting slot (4) with one-side opening is arranged in the brake shell, an axially limiting slot (4) with one-side opening is arranged in the brake shell, an axially limiting slot (4) with one-side opening is arranged in the brake shell, an axially limiting slot (4) with one-side opening is arranged in the brake shell, an axially limiting slot (4) with one-side opening is arranged in the brake shell, an axially limiting slot (4) with one-side opening is arranged in the brake shell, an axially limiting slot (4) with one-side opening is arranged in the brake shell, an axially limiting slot (4) with one-side opening is arranged in the brake shell, an axially limiting slot (4) with one-side opening is arranged in the brake shell, an axially limiting slot (4) with one-side opening is arranged in the brake shell, an axially limiting slot (4) with one-side opening is arranged in the brake shell, an axially limiting slot (4) with one-side opening is arranged in the brake shell, an axially limiting slot (4) with one-side opening is arranged in the brake shell, an axially limiting slot (4) with one-side opening is arranged in the brake shell, an axially limiting slot (4) with one-side opening is arranged in the brake shell, an axially limiting slot (4) with one-side opening is arranged in the brake shell, an axially limiting slot (4) with one-side opening is arranged in the brake shell, an axially limiting slot (4) with one-side opening is arranged in the brake shell, an axially limiting slot (4) with one-side opening is arranged in the brake shell, an axially limiting slot (4) with one-side opening is arranged in the brake shell, an axially limiting slot (4) with one-side opening is arranged in the brake shell, an axially limiting slot (4) with one-side opening is arranged in the brake shell, an axially limiting slot (4) with one-side opening is arranged in the brake shell, an axially limiting slot (4) with one-side opening is arranged in the brake shell, an axially limiting slot (4) with one-side opening is arranged in the brake shell, an axially limiting slot (4) with one-side opening is arranged in the brake shell, an axially limiting slot (4) with one-side opening is arranged in the brake shell, an axially limiting slot (4) with one-side opening is arranged in the brake shell, an axially limiting slot (4) with one-side opening is arranged in the brake shell, an axially limiting slot (4) with one-side opening is arranged in the brake shell, an axially limiting slot (4) with one-side opening is arranged in the brake shell, an axially limiting slot (4) with one-side opening is arranged in the brake shell, an axially limiting slot (4) with one-side opening is arranged in the brake shell, an axially limiting slot (4) with one-side opening is arranged in the brake shell, an axially limiting slot (4) with one-side opening is arranged in the brake shell, an axially limiting slot (4) with one-side opening is arranged in the brake shell, an axially limiting slot (4) with one-side opening is arranged in the brake shell, an axially limiting slot (4) with one-side opening is arranged in the brake shell, an axially limiting slot (4) with one-side opening is arranged in the brake shell, an axially limiting slot (4) with one-side opening is arranged in the brake shell, an axially limiting slot (4) with one-side opening is arranged in the brake shell, an axially limiting slot (4) with one-side opening is arranged in the brake shell, an axially limiting slot (4) with one-side opening is arranged in the brake shell, an axially limiting slot (4) with one-side opening is arranged in the brake shell, an axially limiting slot (4) with one-side opening is arranged in the brake shell, an axially limiting slot (4) with one-side opening is arranged in the brake shell, an axially limiting slot (4) with one-side opening is arranged in the brake shell, an axially limiting slot (4) with one-side opening is arranged in the brake shell, an axially limiting slot (4) with one-side opening is arranged in the brake shell, an axially limiting slot (4) with one-side opening is arranged in the brake shell, an axially limiting slot (4) with one-side opening is arranged in the brake shell, an axially limiting slot (4) with one-side opening is arranged in the brake shell, an axially limiting slot (4) with one-side opening is arranged in the brake shell, an axially limiting slot (4) with one-side opening is arranged in the brake shell, an axially limiting slot (4) with one-side opening is arranged in the brake shell, an axially limiting slot (4) with one-side opening is arranged in the brake shell, an axially limiting slot (4) with one-side opening is arranged in the brake shell, an axially limiting slot (4) with one-side opening is arranged in the brake shell, an axially limiting slot (4) with one-side opening is arranged in the brake shell, an axially limiting slot (4) with one-side opening is arranged in the brake shell, an axially limiting slot (4) with one-side opening is arranged in the brake shell, an axially limiting slot (4) with one-side opening is arranged in the brake shell, an axially limiting slot (4) with one-side opening is arranged in the brake shell, an axially limiting slot (4) with one-side opening is arranged in the brake shell, an axially limiting slot (4) with one-side opening is arranged in the brake shell, an axially limiting slot (4) with one-side opening is arranged in the brake shell, an axially limiting slot (4) with one-side opening is arranged in the brake shell, an axially limiting slot (4) with one-side opening is arranged in the brake shell, an axially limiting slot (4) with one-side opening is arranged in the brake shell, an axially limiting slot (4) with one-side opening is arranged in the brake shell, an axially limiting slot (4) with one-side opening is arranged in the brake shell, an axially limiting slot (4) with one-side opening is arranged in the brake shell, an axially limiting slot (4) with one-side opening is arranged in the brake shell, an axially limiting slot (4) with one-side opening is arranged in the brake shell, an axially limiting slot (4) with one-side opening is arranged in the brake shell, an axially limiting slot (4) with one-side opening is arranged in the brake shell, an axially limiting slot (4) with one-side opening is arranged in the brake shell, an axially limiting slot (4) with one-side opening is arranged in the brake shell, an axially limiting slot (4) with one-side opening is arranged in the brake shell, an axially limiting slot (4 6. A new smart motorized push rod according to claim 1 characterized in that: ​ 7. A new smart motorized push rod according to claim 1 characterized in that: ​ The electric push rod adopts any one of ZigBee, BLE or Wi-Fi wireless communication unit, at this time, the AC permanent magnet motor replaces the wired communication mode by the wireless communication mode, and the wireless communication unit is electrically connected with the control circuit.

8. A new smart motorized push rod according to claim 1 characterized in that: The push rod comprises a screw rod, and the screw rod adopts a threaded screw rod or a ball screw rod.

9. A new smart motorized push rod according to claim 8, characterized by: The rotor of the alternating current permanent magnet motor is provided with multiple pairs of pole permanent magnet, the alternating current permanent magnet motor and the push rod are connected through a transmission gear set, the Hall sensor of the rotor position of the alternating current permanent magnet motor is matched with the reduction ratio of the transmission gear set and the pitch of the push rod screw, so that the closed loop control of the displacement of the push rod can be realized, and the calculation formula of the displacement d of the electric push rod controlled by each Hall state of the Hall position sensor is as follows: Wherein, p is the pole pair number of the AC permanent magnet motor, h is the lead of the screw rod, and k is the gear reduction ratio of the transmission gear set.

10. A new smart motorized push rod according to claim 1 characterized in that: The AC permanent magnet motor comprises an end cover (11), a motor shell (10) and a bottom cover (12), a connecting part one (13) is arranged on the outer wall of the motor shell, connecting part two (14) matched with the connecting part one (13) is arranged on the side peripheral wall of the end cover (11) and the bottom cover (12), the connecting part one (13) and the connecting part two (14) are connected through a connecting piece (15) and make the end cover (11), the motor shell (10) and the bottom cover (12) fixed together, and the cross section of the connecting part one (13) and the connecting part two (14) is in the shape of ear type, square, circle, semicircle or triangle.

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