CN211779268U

CN211779268U - Pilot type electronic expansion valve

Info

Publication number: CN211779268U
Application number: CN201922237719.8U
Authority: CN
Inventors: 张凯
Original assignee: Shanghai Fu Filter Enterprise Development Co ltd
Current assignee: Shanghai Fu Filter Enterprise Development Co ltd
Priority date: 2019-12-13
Filing date: 2019-12-13
Publication date: 2020-10-27
Anticipated expiration: 2029-12-13

Abstract

A pilot-operated electronic expansion valve comprises a first valve needle, wherein a second valve hole and a through sliding chute are respectively arranged in the first valve needle, the through sliding chute is used for communicating the second valve hole with one end of a channel, and the other end of the second valve hole is communicated with the first valve hole; the second valve hole is assembled with one end of a second valve needle, the second valve needle is respectively provided with a valve needle convex plate and a valve needle large end, the valve needle large end is arranged in an adjusting inner cylinder in a clamping groove cylinder and can be axially assembled in a sliding manner, two ends of the clamping groove cylinder are respectively assembled and fixed with the first valve needle and an adjusting rod, and the clamping groove cylinder can axially slide in a fixed sliding hole in a fixed cylinder; the large end of the valve needle is provided with a clamping installation groove and a first magnet block, and an adjusting spring is arranged between the large end of the valve needle and the closed end of the adjusting inner cylinder; the inner wall of the adjusting inner cylinder is further provided with a plurality of clamping grooves along the axial direction of the inner cylinder, the clamping grooves can be assembled with one ends of the clamping blocks in a clamping mode, the other ends of the clamping blocks are arranged in the clamping mounting grooves and are fixedly assembled with the clamping block frame, and the clamping block frame is assembled with the clamping mounting grooves in a sliding mode.

Description

Pilot type electronic expansion valve

Technical Field

The utility model relates to an expansion valve especially relates to a pilot-operated electronic expansion valve.

Background

The electronic expansion valve controls the voltage or current applied to the expansion valve by using the electric signal generated by the regulated parameter, thereby achieving the purpose of regulating the liquid supply amount. The detection device of the electronic expansion valve is used for detecting the position of the valve needle, so as to calculate the opening degree of the valve hole, which is very important for a precisely controlled refrigeration system. The main way at present is to install a magnet on the valve needle and then detect the position through a hall sensor, which is high in precision but high in cost, and the magnet has a risk of demagnetization, so that the later maintenance cost is high.

In addition, in order to achieve more accurate control, a pilot electronic expansion valve is generally adopted, and the principle of the pilot electronic expansion valve is that two valve needles respectively correspond to two valve holes, wherein one valve hole is large and the other valve hole is small. When the cooling device is used, the small valve hole is opened by utilizing the self hydraulic pressure of the cooling liquid, and when the opening degree needs to be adjusted, the opening degree is adjusted through the large valve hole. However, the current adjusting mode cannot fix the smaller valve hole and the valve needle, so that the debugging of the system becomes very difficult after the larger valve hole and the valve needle are adjusted.

SUMMERY OF THE UTILITY MODEL

In view of the above-mentioned defects in the prior art, the present invention provides a pilot-operated electronic expansion valve, which can fix a first valve needle and a second valve needle.

In order to achieve the above object, the utility model provides a pilot-operated electronic expansion valve, including the valve casing, the valve casing is inside for hollow valve pocket, installs the valve body inside the valve pocket, is provided with passageway, first valve opening respectively on the valve body, the first valve opening communicates with passageway one end, and the passageway other end communicates with the input tube, and the input tube imports the liquid refrigerant liquid; the first valve hole is clamped with one end of the first valve needle and can be assembled in a sealing mode, and the first valve hole is communicated with the output hole; the method is characterized in that:

a second valve hole and a through sliding groove are respectively arranged in the first valve needle, the through sliding groove is used for communicating the second valve hole with one end of the channel, and the other end of the second valve hole is communicated with the first valve hole; the second valve hole is assembled with one end of a second valve needle, the second valve needle is provided with a valve needle convex plate and a valve needle large end respectively, the valve needle large end is arranged in an adjusting inner cylinder in a clamping groove cylinder and can be assembled with the adjusting inner cylinder in an axial sliding manner, two ends of the clamping groove cylinder are fixedly assembled with the first valve needle and the adjusting rod respectively, and the clamping groove cylinder can axially slide in a fixed sliding hole in a fixed cylinder;

the large end of the valve needle is provided with a clamping installation groove and a first magnet block, and an adjusting spring is arranged between the large end of the valve needle and the closed end of the adjusting inner cylinder; the inner wall of the adjusting inner cylinder is further provided with a plurality of clamping grooves along the axial direction of the inner cylinder, the clamping grooves can be assembled with one ends of the clamping blocks in a clamping mode, the other ends of the clamping blocks are arranged in the clamping mounting grooves and are fixedly assembled with the clamping block frame, and the clamping block frame is assembled with the clamping mounting grooves in a sliding mode.

Preferably, the valve needle convex plate penetrates out of the through sliding groove.

Preferably, a clamping block spring is arranged between the clamping block frame and the closed end of the clamping groove; at least one of the fixture block and the fixture block frame is made of a permanent magnet.

Preferably, install the guide housing on the valve body, the inside hollow inner cover that is of guide housing, inner cover internally mounted have a fixed section of thick bamboo, the inside hollow fixed slide opening that is provided with of a fixed section of thick bamboo, be provided with on the fixed slide opening side and detect the spout, detect inside block of spout, slidable and install second magnet piece, second magnet piece and detect and install the detection spring between the spout blind end, be fixed with detection switch on the detection spout blind end, detection switch's signal end and PLC's signal end communication are connected, and PLC installs in electric box.

Preferably, the inner side of the fixed sliding hole is also provided with a soft iron plate, the soft iron plate is fixedly assembled with the inner side of the fixed cylinder through a soft iron column, a coil is wound on the soft iron column, and direct current is introduced into the coil to generate magnetism; the soft iron plate and the soft iron column are both made of soft iron, and the first magnet block and the second magnet block are both magnetic and have opposite homopolarity.

Preferably, the first valve needle is fixed on one end of an adjusting rod, the other end of the adjusting rod respectively penetrates through the detecting cylinder and the guide cover, a locking block and a tooth socket are respectively fixed on one end of the adjusting rod, which penetrates through the guide cover, the adjusting rod is respectively assembled with the detecting cylinder and the guide cover in a sealing and sliding manner, the tooth socket is in meshing transmission with a driven gear, the driven gear is in meshing transmission with a driving gear, and the driving gear is fixed on an output shaft of a motor; the motor is driven by the motor driver, and the control end of the motor driver is in communication connection with the signal end of the PLC.

Preferably, the top of the adjusting rod is fixedly assembled with the adjusting cylinder, the adjusting cylinder is internally provided with a hollow adjusting inner cylinder, a conductive big end is clamped in the adjusting inner cylinder and slidably assembled, one end of the conductive big end is in conductive connection with a first lead, a conductive post is fixed at the other end of the conductive big end, the conductive post penetrates through the adjusting cylinder and the adjusting spring and is in conductive connection with a conductive block, one end of the conductive post is in conductive connection with a second lead, the first lead is in conductive connection with the positive pole of a direct-current power supply, the second lead is in conductive connection with the negative pole of the direct-current power supply, the first lead is in conductive connection with the negative pole and the positive pole of a voltmeter respectively, and the signal end of the voltmeter is in communication connection with the signal;

the direct-current power supply outputs constant current, the conductive block, the conductive sheet, the conductive column and the conductive big end are all conductors, the conductive sheet is fixed in the insulating seat, the insulating seat is fixed in the valve cavity, and the insulating seat is made of insulating materials.

Preferably, a groove is formed in one side of the locking block, and the groove and the protrusion are clamped and assembled to relatively fix the locking block; the locking device comprises a locking plate, a locking rod, a locking spring, a locking mounting groove and a stop plate, wherein the protrusion is arranged on the locking plate, the locking plate is fixedly assembled with one end of the locking rod, the other end of the locking rod passes through the locking spring, the locking mounting groove and the stop plate and then is fixedly assembled with a driving plate, the locking mounting groove is arranged on the stop plate, and the stop plate is fixed in a valve cavity;

the driving plate is fixed with a driving column, the open end of the driving column is fixed with a driving pin, the driving pin is arranged in a driving chute, the driving chute is arranged on a movable plate, the movable plate is clamped and slidably arranged in a movable chute, the movable chute is arranged in a movable seat, and the movable seat is fixed in the valve cavity.

Preferably, the bottom of the movable plate and the top surface of the guide cover are respectively assembled and fixed with two ends of a return spring, and the return spring is a tension spring; the top of the movable plate is fixedly assembled with a telescopic shaft of the electromagnet, the electromagnet is fixed on the partition plate, the partition plate is fixed in the valve cavity, the power connection end of the electromagnet is in conductive connection with the movable contact of the contactor, the static contact of the contactor is in conductive connection with the power supply, and the control end of the contactor is in electrical connection with the signal end of the PLC.

Preferably, a second travel switch and a first travel switch are respectively installed at the top of the guide cover and at the corresponding positions of the partition plate and the locking block, and signal ends of the second travel switch and the first travel switch are respectively communicated with a signal end of the PLC.

The utility model has the advantages that:

1. the utility model discloses a fixture block and draw-in groove assembly to can the first needle of relative fixation on the second needle, the uncertainty that first needle was hit when just also preventing the debugging increases debugging efficiency. In addition, the fixation of the first valve needle and the second valve needle can be released as required, so that the normal use of the pilot function is not influenced.

2. The utility model discloses simple structure, and the mode through forming the slide rheostat between conducting block, the conducting strip converts the needle displacement volume, and its precision can compare favourably with hall sensor, but with low costs, maintains simply, and is real durable than leather, very is applicable to among the vibration environment.

Drawings

Fig. 1 is a schematic structural diagram of the present invention.

Fig. 2 is an enlarged view of fig. 1 at F1.

Fig. 3 is an enlarged view of fig. 1 at F2.

Fig. 4 is an enlarged view of fig. 1 at F3.

Detailed Description

The technical solution in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention.

In the description of the present invention, it is to be understood that the terms "upper", "lower", "front", "rear", "left", "right", "top", "bottom", "inner", "outer", and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the drawings, and are only for convenience of description and simplicity of description, and do not indicate or imply that the device or element being referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore, should not be construed as limiting the present invention.

Referring to fig. 1 to 4, the pilot-operated electronic expansion valve of the present embodiment includes a valve housing 110, a hollow valve cavity 111 is disposed inside the valve housing 110, a valve body 330 is mounted inside the valve cavity 111, the valve body 330 is respectively provided with a passageway 332 and a first valve hole 331, the first valve hole 331 is communicated with one end of the passageway 332, the other end of the passageway 332 is communicated with an input pipe 310, and the input pipe 310 inputs liquid refrigerant; the first valve hole 331 is engaged with one end of the first valve needle 360 and is sealably assembled, and the first valve hole 331 is communicated with the output hole 320. In use, liquid refrigerant enters from the input pipe, then passes through the first valve hole 331 to form a gaseous state (similar to an atomizing nozzle), and then is output from the output port to refrigerate an external medium, which is the basic principle of the current compression refrigeration equipment such as an air conditioner.

A second valve hole 361 and a through sliding groove 362 are respectively arranged in the first valve needle 360, the through sliding groove 362 is used for communicating the second valve hole 361 with one end of the channel 332, and the other end of the second valve hole 361 is communicated with the first valve hole 331; the second valve hole 361 is assembled with one end of a second valve needle 340, the second valve needle 340 can seal the second valve hole 361, a valve needle convex plate 341 and a valve needle big end 342 are respectively arranged on the second valve needle 340, the valve needle convex plate 341 penetrates through the through sliding groove 362, the valve needle big end 342 is installed in an adjusting inner cylinder 371 in the clamping groove cylinder 370 and can be axially assembled in a sliding manner, two ends of the clamping groove cylinder 370 are respectively assembled and fixed with the first valve needle 360 and the adjusting rod 350, and the clamping groove cylinder 370 can axially slide in the fixed sliding hole 421;

the large end 342 of the valve needle is provided with a clamping installation groove 3421 and a first magnet block 471, an adjusting spring 460 is installed between the large end 342 of the valve needle and the closed end of the adjusting inner cylinder 371, and the adjusting spring 460 is used for generating elastic force for preventing the large end 342 of the valve needle from moving upwards in the axial direction; the inner wall of the adjusting inner cylinder 371 is further provided with a plurality of clamping grooves 372 along the axial direction, the clamping grooves 372 can be clamped and assembled with one ends of the clamping blocks 910, the other ends of the clamping blocks 910 are installed in the clamping installation grooves 3421 and are assembled and fixed with the clamping block frame 920, the clamping block frame 920 is slidably assembled with the clamping installation grooves 3421, a clamping block spring 930 is installed between the clamping block frame 920 and the closed end of the clamping grooves 372, and the clamping block spring 930 is used for generating elastic force for blocking the clamping block frame 920 from moving rightwards.

At least one of the fixture block 910 and the fixture block holder 920 is made of a permanent magnet. When the fixture block needs to be pushed out of the clamping groove, the coil is connected with direct current, so that magnetism identical to that of the opposite end of the fixture block 910 or the fixture block holder 920 is generated, like poles repel each other, and the fixture block 910 is pushed out of the clamping groove through the magnetic repulsion force.

Install guide cover 410 on valve body 330, the inside hollow inner cover 411 that is of guide cover 410, inner cover 411 internally mounted has a fixed section of thick bamboo 420, and fixed section of thick bamboo 420 is inside to be provided with hollow fixed slide opening 421, is provided with on the fixed slide opening 421 side and detects spout 422, detect the inside block of spout 422, install second magnet piece 472 slidable, install detection spring 480 between second magnet piece 472 and the detection spout 422 blind end, be fixed with detection switch 220 on the detection spout 422 blind end, detection switch 220's signal end and PLC's signal end communication are connected, and PLC installs in electric box 280. In this embodiment, the detection switch is a microswitch. The detection spring 480 is used for generating elastic force for preventing the second magnet block from moving towards the detection switch, and the second magnet block can trigger the detection switch.

The inner side of the fixed sliding hole 421 is further provided with a soft iron plate 430, the soft iron plate 430 is fixedly assembled with the inner side of the fixed cylinder 420 through a soft iron column 440, a coil 450 is wound on the soft iron column 440, and direct current is introduced into the coil 450 to generate magnetism. The soft iron plates 430 and the soft iron columns 440 are made of soft iron, and can conduct magnetism generated by the coils, so that the magnetism is temporarily provided.

In practical use, the coolant may generate an upward lifting force on the valve needle convex plate 341 through hydraulic pressure, so that the second valve needle moves upward against the elastic force of the adjusting spring, thereby flexibly adjusting the opening degree of the second valve hole. When the fixture block corresponds to the clamping groove, the fixture block is clamped into the clamping groove, and the fixture block and the clamping groove are designed in the embodiment, so that the clamping groove can move upwards and downwards in the axial direction.

The first magnet block and the second magnet block are both magnetic and opposite in homopolar, when the valve needle large end moves to a position corresponding to the second magnet block, the first magnet block drives the second magnet block to overcome the detection spring through repulsive magnetic force and move towards the detection switch until the detection switch is triggered, and at the moment, the PLC receives a signal and the second valve needle completely opens the second valve hole. The PLC can move the first valve needle upwards to increase the opening degree of the first valve hole, then the coil is connected with direct current, and the clamping block is pushed out of the clamping groove, so that the movable adjustment of the second valve needle is realized.

The first valve needle 340 is fixed on one end of the adjusting rod 350, the other end of the adjusting rod 350 respectively penetrates through the detecting cylinder 430 and the guide cover 410, one end of the adjusting rod 350, which penetrates through the guide cover 410, is respectively fixed with a locking block 830 and a tooth space 351, the adjusting rod 350 is respectively assembled with the detecting cylinder 430 and the guide cover 410 in a sealing and sliding manner, the tooth space 351 is in meshing transmission with the driven gear 512, the driven gear 512 is in meshing transmission with the driving gear 511, the driving gear 511 is fixed on an output shaft of the motor 230, the driving gear 511 can be driven to rotate circumferentially after the motor 230 is electrified, and the motor 230 has a power-.

The motor 230 is driven by a motor driver, the motor 230 is a stepping motor or a servo motor, and a control end of the motor driver is in communication connection with a signal end of the PLC, so that the PLC can control the operation of the motor. The top of the adjusting rod 350 is fixedly assembled with an adjusting cylinder 740, a hollow adjusting inner cylinder 741 is arranged inside the adjusting cylinder 740, a conductive big end 720 is clamped and slidably assembled inside the adjusting inner cylinder 741, one end of the conductive big end 720 is electrically connected with a first conducting wire 251, a conductive post 721 is fixed at the other end of the conductive big end 720, the conductive post 721 penetrates through the adjusting cylinder 740 and the adjusting spring 730 and is electrically connected with a conductive block 261, the adjusting spring 730 is used for generating elastic force for pushing the conductive block 261 to the conductive sheet 262, so that the conductive block 261 is always kept to be tightly pressed and electrically conductive with the conductive sheet 262, one end of the conductive sheet 262 is electrically connected with a second conducting wire 252, the first conducting wire 251 is electrically connected with a positive electrode of a direct-current power supply, the second conducting wire 252 is electrically connected with a negative electrode of the direct-current power supply, the second conducting wire 252 and the first conducting wire 251 are respectively electrically connected with a negative electrode and a, The voltage value between the first conducting wires 251 and the signal end of the voltmeter are in communication connection with the signal end of the PLC. The DC power supply is used to output a constant current, and in this embodiment, the DC power supply is an AC-DC converter. When the valve seat is used, the sliding rheostat is formed between the conducting plate and the conducting block, the conducting block is in contact conduction with the conducting plates at different parts, so that the resistance between the conducting block and the conducting block is changed, the voltage is changed accordingly, the resistance value between the conducting plate and the conducting block can be calculated through the change of the voltage, however, only the resistance value at the conducting plate is changed, the contact position between the conducting plate and the conducting block can be deduced according to the size, the conductivity and the like of the conducting plate, the position of the conducting block on the conducting plate is converted, and the displacement and the relative position of the first valve needle are calculated (when the first valve needle is in the initial state in which the first valve hole is sealed at the lowest end, the parameter values. The design structure is very simple, the accuracy rate is high, and the device is more real and durable.

The conductive block 261, the conductive sheet 262, the conductive column 721 and the conductive big end 720 are all conductors, the conductive sheet 262 is fixed in the insulating seat 710, and the insulating seat 710 is fixed in the valve cavity 111.

A groove 831 is arranged on one side of the locking block 830, and the groove 831 is clamped and assembled with the protrusion 821 to fix the locking block relatively, namely, fix the adjusting rod and the first valve needle axially; the boss 821 is arranged on the locking plate 820, the locking plate 820 and one end of the locking rod 633 are assembled and fixed, the other end of the locking rod 633 passes through the locking spring 840, the locking installation groove 811 and the stop plate 810 and then is assembled and fixed with the driving plate 630, the locking installation groove 811 is arranged on the stop plate 810, the stop plate 810 is fixed in the valve cavity 111, and the locking spring 840 is used for generating pushing force for the locking plate 820 to move towards the locking block 830;

a driving column 631 is fixed on the driving plate 630, a driving pin 632 is fixed on an open end of the driving column 631, the driving pin 632 is installed in a driving chute 611, the driving chute 611 is arranged on the movable plate 610, the movable plate 610 is clamped and slidably installed in the movable chute 131, the movable chute 131 is arranged in the movable seat 130, and the movable seat 130 is fixed in the valve cavity 111;

the bottom of the movable plate 610 and the top surface of the guide housing 410 are fixedly assembled with two ends of a return spring 620 respectively, and the return spring is a tension spring; the top of the movable plate 610 is fixedly assembled with a telescopic shaft of the electromagnet 210, the electromagnet is fixed on the partition plate 120, the partition plate 120 is fixed in the valve cavity, the power connection end of the electromagnet 210 is electrically connected with the movable contact of the contactor, the static contact of the contactor is electrically connected with a power supply, and the control end of the contactor is electrically connected with the signal end of the PLC, so that the PLC can control the start and stop of the electromagnet 210.

At the initial state, the movable plate 610 is pulled downwards by the return spring 620, so that the driving inclined groove 611 is always at the bottommost part, the locking spring generates a thrust force to the locking block on the locking plate 820 at the moment, and the locking plate 820 is tightly matched with the locking block to relatively fix the adjusting rod.

When the first valve needle needs to be adjusted, the PLC controls the contactor to be closed, the electromagnet is electrified to drive the movable plate 610 to move upwards, so that the driving chute 611 enables the locking plate 820 to overcome the elastic force of the locking spring 840 to move towards the stop plate through the driving pin, and the locking plate is separated from the locking block; and then the motor is started, and the position of the first valve needle can be adjusted by axially adjusting the adjusting rod through the meshing of the driven gear and the tooth groove.

Preferably, the top of the guide cover 410 and the corresponding position of the partition 120 and the locking block are respectively provided with a second travel switch 272 and a first travel switch 271, and the signal ends of the second travel switch 272 and the first travel switch 271 are respectively in communication connection with the signal end of the PLC. When the locking block triggers the second travel switch 272 or the first travel switch 271, the PLC determines that the upward or downward movement reaches the maximum position.

The details of the present invention are well known to those skilled in the art.

The foregoing has described in detail preferred embodiments of the present invention. It should be understood that numerous modifications and variations can be devised by those skilled in the art in light of the teachings of the present invention without undue experimentation. Therefore, the technical solutions that can be obtained by a person skilled in the art through logic analysis, reasoning or limited experiments based on the prior art according to the concepts of the present invention should be within the scope of protection defined by the claims.

Claims

1. The pilot-operated electronic expansion valve comprises a valve shell, wherein a hollow valve cavity is arranged inside the valve shell, a valve body is arranged inside the valve cavity, a passageway and a first valve hole are respectively arranged on the valve body, the first valve hole is communicated with one end of the passageway, the other end of the passageway is communicated with an input pipe, and liquid refrigerant is input into the input pipe; the first valve hole is clamped with one end of the first valve needle and can be assembled in a sealing mode, and the first valve hole is communicated with the output hole; the method is characterized in that:

2. The pilot-operated electronic expansion valve according to claim 1, wherein: the valve needle convex plate penetrates out of the through sliding groove.

3. The pilot-operated electronic expansion valve according to claim 1, wherein: a clamping block spring is arranged between the clamping block frame and the closed end of the clamping groove; at least one of the fixture block and the fixture block frame is made of a permanent magnet.

4. The pilot-operated electronic expansion valve according to claim 1, wherein: install the guide housing on the valve body, the inside hollow inner cover that is of guide housing, inner cover internally mounted have a fixed section of thick bamboo, the inside hollow fixed slide opening that is provided with of a fixed section of thick bamboo, be provided with on the fixed slide opening side and detect the spout, detect inside block of spout, slidable and install the second magnet piece, second magnet piece and detect and install the detection spring between the spout blind end, be fixed with detection switch on detecting the spout blind end, detection switch's signal end and PLC's signal end communication are connected, and PLC installs in electric box.

5. The pilot-operated electronic expansion valve according to claim 1, wherein: the inner side of the fixed sliding hole is also provided with a soft iron plate, the soft iron plate is fixedly assembled with the inner side of the fixed cylinder through a soft iron column, a coil is wound on the soft iron column, and direct current is introduced into the coil to generate magnetism; the soft iron plate and the soft iron column are both made of soft iron, and the first magnet block and the second magnet block are both magnetic and have opposite homopolarity.

6. The pilot-operated electronic expansion valve according to claim 1, wherein: the first valve needle is fixed on one end of an adjusting rod, the other end of the adjusting rod penetrates through the detection cylinder and the guide cover respectively, a locking block and a tooth groove are fixed on one end of the adjusting rod, which penetrates through the guide cover, respectively, the adjusting rod is sealed and slidably assembled with the detection cylinder and the guide cover respectively, the tooth groove is in meshing transmission with a driven gear, the driven gear is in meshing transmission with a driving gear, and the driving gear is fixed on an output shaft of a motor; the motor is driven by the motor driver, and the control end of the motor driver is in communication connection with the signal end of the PLC.

7. The pilot-operated electronic expansion valve according to claim 1, wherein: the top of the adjusting rod is fixedly assembled with the adjusting cylinder, the adjusting cylinder is internally provided with a hollow adjusting inner cylinder, a conductive big end is clamped and slidably assembled in the adjusting inner cylinder, one end of the conductive big end is conductively connected with a first wire, a conductive post is fixed at the other end of the conductive big end, the conductive post penetrates through the adjusting cylinder and the adjusting spring and then is conductively connected with a conductive block, and the conductive block is in contact conduction with the conductive piece; one end of the conducting strip is in conductive connection with a second lead, the first lead is in conductive connection with the positive electrode of the direct-current power supply, the second lead is in conductive connection with the negative electrode of the direct-current power supply, the second lead and the first lead are in conductive connection with the negative electrode and the positive electrode of the voltmeter respectively, and the signal end of the voltmeter is in communication connection with the signal end of the PLC;

8. The pilot-operated electronic expansion valve according to claim 6, wherein: a groove is formed in one side of the locking block, and the groove and the protrusion are clamped and assembled to relatively fix the locking block; the locking device comprises a locking plate, a locking rod, a locking spring, a locking mounting groove and a stop plate, wherein the protrusion is arranged on the locking plate, the locking plate is fixedly assembled with one end of the locking rod, the other end of the locking rod passes through the locking spring, the locking mounting groove and the stop plate and then is fixedly assembled with a driving plate, the locking mounting groove is arranged on the stop plate, and the stop plate is fixed in a valve cavity;

9. The pilot-operated electronic expansion valve according to claim 8, wherein: the bottom of the movable plate and the top surface of the guide cover are respectively fixedly assembled with two ends of a return spring, and the return spring is a tension spring; the top of the movable plate is fixedly assembled with a telescopic shaft of the electromagnet, the electromagnet is fixed on the partition plate, the partition plate is fixed in the valve cavity, the power connection end of the electromagnet is in conductive connection with the movable contact of the contactor, the static contact of the contactor is in conductive connection with the power supply, and the control end of the contactor is in electrical connection with the signal end of the PLC.

10. The pilot-operated electronic expansion valve according to claim 4, wherein: and the top of the guide cover, the corresponding positions of the partition plate and the locking block are respectively provided with a second travel switch and a first travel switch, and the signal ends of the second travel switch and the first travel switch are respectively communicated with the signal end of the PLC.