CN204330201U - Based on the mechanical seal face friction torque measurement mechanism of self-powered and Wireless Data Transmission - Google Patents

Abstract

This technology provides a mechanical seal end face friction torque measurement device based on self-powered and wireless data transmission that can realize accurate torque measurement of the mechanical seal to be tested in the mechanical seal performance test device, which includes a shaft sleeve, a transmission pin, a force sensor, a signal Processor, wireless transmitting module, wireless receiving module, self-powered module; the main shaft passes through the shaft sleeve, the mechanical seal of the end surface friction torque to be measured is fitted on the shaft sleeve, the moving ring is connected to the shaft sleeve, and the static ring is fixed in the sealing chamber Above; the torque generated by the friction of the end faces of the dynamic and static rings of the mechanical seal is balanced with the torque transmitted from the main shaft to the bushing through the drive pin; this torque is measured by the circumferential force measured by the force sensor attached to the drive pin The measured circumferential force is processed by the signal processor and transmitted to the wireless receiving module by the wireless transmitting module; the electric energy generated by the rotation of the main shaft or the shaft sleeve is transmitted to the signal processor and wirelessly through the self-powered module Module power supply.

Description

Mechanical seal end face friction torque measurement device based on self-power supply and wireless data transmission

technical field

The technology belongs to the technical field of testing, and in particular relates to a test device for measuring the frictional torque of a mechanical seal end face.

Background technique

The increasing shortage of resources and the continuous deterioration of the environment have put forward the production requirements of zero leakage and zero discharge for enterprises. Mechanical seal, as the main shaft seal of the moving equipment in industrial production, on the one hand provides protection for the leakage prevention of the equipment, on the other hand, due to the friction and wear of the end face, it also consumes the shaft power. For this reason, people continue to work hard to find suitable end face specific pressure and materials to reduce end face friction power consumption, prolong service life, and at the same time ensure the sealing performance of mechanical seals. However, the quality of the material matching of the sealing pair and the appropriateness of the specific pressure of the end face are mainly reflected in the friction torque of the end face.

The end face friction torque measurement methods of the mechanical seal performance testing device in the known technology at present include the anti-support force method and the transfer method. There are four types of end-face friction torque measurement techniques developed from these two methods:

Install a load cell on the rotating seal chamber to connect to the torque transducer. As proposed by Mayer (Mechanical Seal. Beijing: Chemical Press, 1981) and patent CN103630301, etc., a torque sensor is installed on the rotating seal cavity to measure the frictional torque technology of the seal end face. This technology needs to support the sealing chamber, and the friction of the rotating support of the sealing chamber has a non-negligible influence on the test accuracy.

A torque speed sensor is installed between the motor and the power shaft. Such as Silvaggio (Silvaggo J A, Lipski M J, and Van Bramer K G. Successful Field Operation through Seal Development and Testing. Lubrication Engineering, 1987, 43(6): 433-439) and literature (high parameter mechanical seal test bench data Acquisition and control system. Petroleum Machinery, 2004, Volume 32, No. 1), etc. proposed to install a torque speed sensor between the motor and the bearing seat to measure the friction torque of the mechanical seal end face. During the test, the torque measured by this technique is the total torque on the main shaft of the test device, including the friction torque of the tested sealing end face, the friction resistance torque of the main bearing and the stirring torque of the rotating parts of the mechanical seal in the sealing medium. Since the friction resistance torque of the main bearing bearing different axial forces and the stirring torque of the rotating parts of the mechanical seal in the sealing medium of different pressures cannot be directly measured, the friction resistance torque of the main bearing under no load and the sealing medium at constant The stirring torque is replaced by the depressed stirring torque, which has a great impact on the measurement accuracy of the end face friction torque; in addition, since the total torque of the mechanical seal test device is more than 5-7 times the normal torque when it is started, it needs to be equipped with a large The torque speed sensor with the diameter of the stress shaft, while the end face friction torque of the mechanical seal test device under normal operation is small, if this torque speed sensor is used to measure the end face friction torque of the mechanical seal, the generated shaft strain will be small and the measurement accuracy will be low . In order to improve the measurement accuracy, the diameter of the stress axis of the selected torque sensor should be smaller, but the stress axis with a smaller diameter is prone to plastic deformation or even fracture, so the measurement accuracy and the size of the stress axis cannot be combined.

A torque sensor is installed between the static ring seat and the static ring. Sun Jianjun (Discussion on the controllability of mechanical seals and their engineering applications. Chinese Journal of Mechanical Engineering, 2005, 41 (2): 15-19) proposed to install a torque sensor between the static ring seat and the static ring to measure the friction of the seal end face The torque method is to connect a small-range and large-diameter cylindrical torque sensor in series between the static ring seat and the static ring, and the friction torque generated by the rotation of the moving ring to drive the deflection of the static ring is balanced by the resistance torque of the torque sensor to measure the mechanical torque. Seal face friction torque. The advantage of this method is that the sensor is simple in structure and easy to install, especially eliminating the influence of the friction resistance torque of the O-ring between the static ring and the static ring seat on the measurement, but the design and manufacture of small-range and large-diameter cylindrical torque sensors Difficulties exist, and effective breakthroughs have not been obtained. For mechanical seals with bellows static rings, the end face friction torque can be measured by the method in the patent ZL 200610039084.5 "multi-parameter measurable and controllable high-speed mechanical seal performance test device". The measurement system described in this method consists of a static ring seat and a guide cylinder. , angular displacement transmission fan-shaped tooth piece, angular displacement sensor and pinion; one end of the guide cylinder is tightly connected with the inner hole thread of the static ring support ring, and the other end of the guide cylinder is looped in the inner hole of the gland of the static ring seat and passed through the shaft sleeve protrudes outside the seal chamber. By measuring the deflection of the guide cylinder protruding from the outside of the sealing cavity by the angular displacement sensor, the change of the torsion angle of the elastic element of the mechanical seal before and after operation can be measured, and then the end face friction torque can be calculated according to the stiffness of the elastic element. This measurement method can transmit the angular displacement of the static ring to the guide cylinder without loss, to the sector gear, to the pinion, and then to the angular displacement sensor, avoiding the interference of the additional torque on the measured value. However, the transmission error between the sector gear and the pinion seriously affects the measurement accuracy.

Patent CN102183327B relates to a method for measuring frictional torque on the end face of a mechanical seal, that is, placing a coin-type torque sensor on the notch of the static ring. Using the principle of torque balance that the total torque of the static ring is equal to zero during normal operation, the friction torque of the end surface is obtained by adding the resistance torques measured by the sensor. For a mechanical seal measurement system consisting of a moving ring, a static ring, an O-ring for static ring sealing, a load cell support frame, a load cell, an end face bearing, an end face bearing seat and a seal chamber end cover, two load cells are installed axially symmetrically. On the load cell bracket on the inner hole side of the end cover of the sealing chamber, the force measuring points are arranged axially symmetrically along the tangential direction on the sides of the two anti-rotation pin holes of the static ring. During work, due to the end surface friction torque Mm between the dynamic and static rings, the static ring has a tendency to follow the rotation of the dynamic ring, this trend is caused by the frictional resistance of the inner hole of the seal chamber end cap on the static ring seal O-ring The moment Mf and the resistance moment M1s generated by the load cell installed on the side of the anti-rotation pin hole are balanced, that is, Mm=Mf+M1s. Among them, the frictional resistance moment Mf between the inner hole of the static ring seat and the O-ring can be pre-determined in the load sensor on the side of the two anti-rotation pin holes of the static ring in the sealing chamber; the load installed on the side of the anti-rotation pin hole in the working state The resistance moment Ms generated by the sensor is obtained by multiplying the tangential force equivalent around the static ring measured by the sensor by the distance (arm) between the force measuring points of the two load cells. The disadvantage of this method is also obvious, because it is necessary to measure the friction resistance moment of the inner hole of the end cover of the sealing chamber that the O-ring is subjected to, and the friction coefficient of the O-ring is different between individuals due to the material, resulting in accurate measurement of the end surface friction torque poor degree.

A torque sensor is provided between the sleeve and the shaft. For example, the patent CN103267613A proposes to open a U-shaped opening symmetrical to the central section of the sleeve at both ends of the sleeve, and to set a transmission pin on the main shaft corresponding to the U-shaped opening; to process two sections of threads with equal pitch and opposite rotation direction in the middle of the sleeve. Two nuts are screwed on it, and two moving ring seats in the mechanical seal to be tested are respectively installed on the back side; the moving ring seat and the shaft sleeve slide in the axial direction and are connected in the circumferential direction; the transmission pin is provided with a circumferential force sensor. To indirectly measure the end face friction torque. It should be pointed out that this patent does not mention the detailed implementation of the torque sensor arrangement, that is, the specific and effective transmission of wireless signals at high speeds and the long-term power supply issues during wireless signal transmission.

Contents of the invention

The purpose of this technology is to provide a mechanical seal end face friction torque measurement device that can realize the accurate measurement of the torque of the mechanical seal to be tested in the mechanical seal performance test device, and can self-powered and wirelessly transmit data during the working process.

The mechanical seal end face friction torque measurement device based on self-power supply and wireless data transmission described in this technology includes a shaft sleeve with a U-shaped opening on the same busbar at both ends, a transmission pin connected to the main shaft through the U-shaped opening, and a force Sensor, signal processor, wireless transmitting module, wireless receiving module, self-powered module; the main shaft passes through the shaft sleeve, the mechanical seal of the friction torque of the end surface to be measured is sleeved on the shaft sleeve, the moving ring is connected to the shaft sleeve, and the static ring is fixed On the sealing cavity; the characteristic is: the torque generated by the dynamic and static rings of the mechanical seal due to the friction of the end faces is balanced with the torque transmitted from the main shaft to the shaft sleeve through the transmission pin; this torque is made by sticking on the transmission pin The product of the circumferential force measured by the force sensor and the force arm of the force measuring point is determined. The measured circumferential force is processed by the signal processor and transmitted to the wireless receiving module by the wireless transmitting module; the electric energy generated by the rotation of the main shaft or the shaft sleeve passes through the self-powered module Provides power to the signal processor and wireless transmitter module.

The above-mentioned mechanical seal end face friction torque measurement device based on self-power supply and wireless data transmission is characterized in that the self-power supply module includes a magnet fixed outside the sealing chamber, a coil winding that rotates with the main shaft, a rectifier circuit and a voltage stabilization circuit , the rotating coil winding cuts the magnetic force line to generate an induced electromotive force, and then it is processed by a rectifier circuit and a voltage stabilizing circuit to become a stable DC power supply.

The above-mentioned mechanical seal end face friction torque measurement device based on self-power supply and wireless data transmission is characterized in that the end of the shaft sleeve adopts a closed structure to wrap the end of the main shaft, and the end of the shaft sleeve is connected to a placement box with a built-in signal A processor, a wireless transmitting module, a rectification circuit and a voltage stabilizing circuit, and the output end of the coil winding is connected with the rectifying circuit and the voltage stabilizing circuit.

The above-mentioned mechanical seal end face friction torque measurement device based on self-power supply and wireless data transmission is characterized in that the self-power supply module includes a piezoelectric wafer that rotates with the main shaft, a pressure block and a voltage stabilizing circuit; When it is squeezed by the pressure block rotating with the main shaft, the distance between the positive and negative charges inside it will decrease, so some of the free charges originally attached to the surface of the piezoelectric wafer will be released and passed through the voltage stabilizing circuit. Process becomes a stable DC power supply. Conversely, when the piezoelectric wafer returns to its original state, the distance between the positive and negative charges inside it becomes larger, and a larger polarization intensity appears; at this time, the surface of the piezoelectric wafer will re-adsorb part of the charge, which is also a free charge. Continuously being released provides the conditions.

The above-mentioned mechanical seal end face friction torque measurement device based on self-power supply and wireless data transmission is characterized in that the end of the shaft sleeve adopts a closed structure to wrap the end of the main shaft, and the end of the shaft sleeve is connected to a placement box with a built-in signal A processor, a wireless transmitting module, a voltage stabilizing circuit, a piezoelectric chip and a pressure block; the outer circular surface of the piezoelectric chip is pasted on the inner hole wall of the placement box, and the pressure block is pasted on the inner wall of the piezoelectric chip.

The above-mentioned mechanical seal end face friction torque measurement device based on self-power supply and wireless data transmission is characterized in that, between the two ends of the shaft sleeve and the main shaft, three or more balls. In this way, the friction can be reduced, so that the dynamic and static ring friction torque can be transmitted to the force sensor attached to the transmission pin almost without loss.

The advantages and positive effects of this technology:

The precise measurement of the friction torque of the end face of the mechanical seal is realized. The end face friction torque is transmitted to the shaft sleeve through the main shaft and the transmission pin with little loss. The accuracy is improved by multiplying the force measured by the piezoelectric sensor by the corresponding force arm (the distance from the force sensor to the centerline of the spindle) to obtain the end face friction torque.

A U-shaped opening is provided on the shaft sleeve, a transmission pin is fixed on the main shaft corresponding to the U-shaped opening, and a force sensor is placed on the side wall of the transmission pin and the side wall of the U-shaped opening. The friction torque of the end face is obtained by multiplying the circumferential force on the side wall of the transmission pin by the corresponding force arm when the mechanical seal test device is in normal operation. Compared with the end face friction torque obtained by placing a coin-type torque sensor at the opening of the static ring anti-rotation pin, it avoids the friction resistance torque between the static ring seal O-ring and the inner hole of the seal chamber end cover, and improves the accuracy of actual measurement Spend.

The shaft sleeve adopts a semi-closed structure to wrap the end of the main shaft, and the placement box at the end is directly connected with the shaft sleeve and integrated with the shaft sleeve. Signal processor (including signal amplification module, signal conditioning module, single-chip microcomputer with A/D conversion function, etc.), wireless transmission module, rectification circuit, and voltage stabilization circuit are all placed in the placement box at the end of the spindle and rotate with the shaft sleeve. When installing, you only need to put the shaft sleeve with mechanical seal on the main shaft, and fix the transmission pin at the U-shaped opening of the shaft sleeve through the screw screwed into the screw hole of the main shaft. When disassembling, you only need to remove the transmission pin. It is convenient and quick to remove the bushing together with the set-up box from the main shaft.

In this test device, balls are added between the main shaft and the shaft sleeve, so that the original static friction between the main shaft and the shaft sleeve becomes sliding friction, which improves the accuracy of the end surface friction torque measurement.

The collected signal is sent to the off-axis signal receiving end by means of wireless data transmission, which avoids the winding problem of the transmission signal line when measuring the dynamic torque signal.

The self-powered module cleverly uses the mechanical seal to test the high-speed rotating spindle, and uses the high-speed rotation of the spindle to drive the coil winding to rotate around the magnet fixed in the sealed cavity. The rotating coil winding cuts the magnetic force line to generate an induced electromotive force as a power supply; Chip and pressure block, under the centrifugal force of the pressure block, the positive and negative charges on the inner and outer surfaces of the piezoelectric chip are redistributed to form a positive and negative charge surface and become a power source. Once the main shaft of the mechanical seal performance testing machine starts to run, the self-power supply module will start to generate power. As long as the mechanical seal performance test machine does not stop running, the self-power supply module will continue to supply power, which solves the long-term power supply requirements of the self-power supply module for the signal processor and wireless transmission module. , avoiding the phenomenon that the dry battery or lithium battery power supply system needs to stop and disassemble the device to replace the battery during the test process.

Description of drawings

Figure 1 is a schematic diagram of a mechanical seal end face friction torque measurement device based on self-power supply and wireless data transmission;

Fig. 2 is an enlarged view of the main shaft, bushing, magnet, coil winding, placement box, etc. in Fig. 1;

Fig. 3 is a partial view to A in Fig. 1;

Fig. 4 is a schematic diagram of another mechanical seal end face friction torque measurement device based on self-power supply and wireless data transmission;

Fig. 5 is an enlarged view of the main shaft, bushing, piezoelectric wafer, pressure block, placement box, etc. in Fig. 4;

Fig. 6 is the B-B sectional view of Fig. 5;

Figure 7 is a schematic diagram of the working process of the wireless transmission module NRF24L01;

Fig. 8 is the block diagram of signal processing and transmitting module;

Fig. 9 is a block diagram of a signal receiving and processing module.

In the figure, the main shaft 1, the shaft sleeve 2, the U-shaped opening 21 at the front end, the U-shaped opening 23 at the rear end, the ball 3, the sealing chamber 4, the end cover 41, the side leakage chamber end cover 5, the installation box 6, and the static ring O-ring 71, static ring 72, moving ring 73, moving ring O-ring 74, support ring 75, spring 76, moving ring seat 77, nut 78, short pin 79, transmission pin 8, force sensor 9, magnet 101, coil winding 102 , a rectifier circuit 103, a voltage stabilizing circuit 104, a pressure block 108, and a piezoelectric chip 109.

Detailed ways

The technology will be further described below in combination with schematic diagrams and specific implementation methods:

Referring to Figs. 1-6, the outer periphery of the main shaft 1 forms a rotational connection with the bushing 2 through balls 3 . The right-hand end of axle sleeve 2 is closed, and main shaft stretches in the axle sleeve. The main shaft and the shaft sleeve pass through the sealing chamber 4 with end caps 41 at both ends, and the right end of the sealing chamber is fixed with a side leakage chamber end cap 5 . The outside of the closed end of the right end of the axle sleeve is fixed with a placement box 6 located in the end cover of the side leakage cavity.

The mechanical seal to be tested includes a static ring O-ring 71, a static ring 72, a moving ring 73, a moving ring O-ring 74, a supporting ring 75, a spring 76, a moving ring seat 77, a nut 78, a short pin 79, and the like. The moving ring 73 and the moving ring seat 77 slide in the axial direction and are connected in the circumferential direction. Between the moving ring seat 77 and the moving ring 73, a spring 76, a supporting ring 75, and a moving ring O-ring 74 are sequentially arranged; the moving ring 73 passes through Seal between the moving ring O-ring 74 and the shaft sleeve. The support ring 75 is slidingly connected with the moving ring seat 77 in the axial direction. The static ring 72 is sealed and connected with the central hole on the end cover through the static ring O-ring 71 arranged on the outer periphery of the static ring 72; the static ring 72 and the moving ring 73 are opposite to each other in the axial direction. There are two sections of thread with equal pitch and opposite direction of rotation in the middle of the bushing 2; two nuts 78 respectively cooperate with the threads; a short pin 79 parallel to the axis of the bushing extends into the short pin holes opened on the two nuts at the same time Inside; the back sides of the two nuts are respectively two moving ring seats 77; the moving ring seats 77 are connected with the shaft sleeve in axial sliding and circumferential positioning.

The two ends of the shaft sleeve protruding from the end cover are provided with U-shaped openings 21 and 23 whose centerlines are on the same busbar, and a transmission pin 8 is connected with a screw on the main shaft 1 corresponding to the U-shaped opening 23.

A force sensor 9 is pasted on the side wall of the transmission pin corresponding to the side wall of the U-shaped mouth, which is used to detect the size of the circumferential force between the side wall of the U-shaped mouth and the transmission pin. Force sensor 9 uses FLEXIFORCE A310 piezoelectric film sensor, which has better linearity, drift, hysteresis, temperature sensitivity and higher cost performance than other piezoelectric film sensors. The detection data of the force sensor 9 is transmitted to the signal conditioning amplifier circuit.

The signal processing and transmitting module is composed of a signal conditioning amplifier circuit, a 3.3V low-voltage low-power single-chip microcomputer STC12LE5608AD with A/D conversion function, a wireless transmitting module NRF24L01, and a self-powered module. The wireless transmission module is composed of a signal conditioning amplifier circuit, a low-power radio frequency device, and an antenna. The self-power supply module supplies power to the signal conditioning amplifier circuit, single-chip microcomputer, wireless transmission module and the like. The physical quantity measured by the FLEXIFORCE A310 piezoelectric film sensor is converted into an analog signal by the signal conditioning amplifier circuit, converted into a digital signal by the AD conversion circuit of the single chip microcomputer, and finally transmitted by the wireless transmission module. The power supply voltage of the single chip microcomputer STC12LE5608AD is the same as that of the wireless transmission module NRF24L01. The self-power supply module starts to generate power with the operation of the mechanical seal performance test, and supplies power to each functional unit of the wireless signal transmission end.

Through the internal force of the piezoelectric film sensor FLEXIFORCE A310, the charge change is generated and the voltage signal is output after the signal is amplified and adjusted by the amplifying circuit. The AD conversion circuit of the STC12LE5608AD single-chip microcomputer is converted from the analog signal to the digital signal, and then wirelessly transmitted through the wireless transmission module NRF24L01. data transmission.

NRF24L01 is a single-chip wireless transceiver chip produced by NORDIC that works in the ISM frequency band of 2.4GHz~2.5GHz. It has the following advantages: output power channel selection and protocol settings can be set directly through the SPI interface; almost can be connected to various single-chip microcomputer chips, and complete wireless data transmission work; extremely low current consumption.

As shown in Figure 7, the working process of the wireless transmission module NRF24L01: it starts to sleep and wake up mode, this mode has extremely low current consumption, which greatly saves the power supply; The mode changes to the normal working mode, transmitting 8 effective characters and check digits; when the check digit transmission is completed, it returns to the sleep mode and waits for the next set of data to enter.

The signal receiving and processing module is set outside the sealed chamber, which includes a wireless receiving module NRF24L01, a low-power single-chip microcomputer, a host computer, Labview data processing and display unit, etc. The wireless receiving module receives the signal sent by the wireless sending module, and sends it to the single-chip microcomputer after conditioning, and finally the single-chip microcomputer transmits it to the host computer through the serial port, and then sends it to the Labview data processing and display unit for data processing, real-time display, printing and saving. At the data receiving end, the 5V power supply supplies power to the wireless receiving module, low-power single-chip microcomputer, etc.

The Labview processing and display unit adopts a modular development and integration method, which is composed of a serial port input sub-module, a real-time data display sub-module, a data processing (curve fitting) sub-module, a real-time data storage and report generation sub-module, and a remote monitoring sub-module; Enter the Labview processing display unit through the serial port input module, and the data processing module performs friction torque data curve fitting and displays it on the host computer interface through the data real-time display module; at the same time, the processed data is saved in the form of a report on the host computer.

Ring grooves are formed on the main shaft along the circumferential direction between the two ends of the main shaft and the shaft sleeve, and three or more balls 3 are evenly placed respectively. The friction torque between the main shaft and the shaft sleeve is the rolling friction torque, which reduces friction and is almost negligible compared to the end face friction torque, so that the friction torque of the dynamic and static rings is transmitted to the main shaft through the shaft sleeve almost without loss. According to the mechanical seal The principle of balance between the torque generated by the end face friction of the dynamic and static rings and the torque transmitted from the main shaft to the bushing through the transmission pin, the circumferential force measured by the piezoelectric sensor pasted on the transmission pin is multiplied by the force arm of the force measurement point. The end face friction torque can be obtained.

There are two types of self-powered modules, one is based on the principle of electromotive force generated by coils cutting magnetic force lines, see Figure 1-3; the other is based on the positive piezoelectric effect, that is, piezoelectric wafers will appear on the surface under pressure. Self-powered modules designed according to the principle of different polarity charges, see Figure 3-5.

Referring to Figures 1-3, the self-powered module designed based on the principle that the coil cuts the magnetic field lines to generate electromotive force includes a magnet 101 fixed on the end cover of the leak detection chamber, a coil winding 102 rotating with the main shaft, a rectifier circuit 103 and a voltage stabilizing circuit 104, The main part of the coil winding 102 extends into the magnet 101, and the output end of the coil winding is connected with a rectifier circuit and a voltage stabilizing circuit. The rotating coil winding cuts the magnetic field lines to generate induced electromotive force and sends it to the rectifier circuit and the voltage stabilization circuit for processing. The signal conditioning amplifier circuit, the 3.3V low-voltage low-power single-chip microcomputer STC12LE5608AD with A/D conversion function, the wireless transmission module NRF24L01, the rectifier circuit, and the voltage stabilization circuit are all placed in the placement box. The placement box is connected with the shaft sleeve and rotates synchronously with the shaft sleeve and the main shaft. When installing (or dismantling), you only need to fix the drive pin at the U-shaped mouth to the main shaft with screws (or remove it from the main shaft), and then install the shaft sleeve together with the placement box on the shaft (or remove it from the shaft) . According to the principle of electromagnetic induction, the coil winding is fixed in the placement box and follows the high-speed rotation of the main shaft to continuously cut the magnet fixed on the end cover of the leak detection chamber, resulting in the change of the magnetic flux of the magnetic field to generate an induced electromotive force; the generated induced electromotive force is rectified and stabilized Finally, a stable power supply voltage is obtained, which avoids the situation that the experimental time is too short due to the limited power supply capacity of ordinary dry batteries or lithium batteries, and it is necessary to frequently stop the experiment to disassemble the device to replace the battery, and cannot continuously obtain effective data on the end-face friction torque.

Referring to Figures 3-5, the self-powered module designed based on the principle that charges of different polarities appear on the surface of piezoelectric wafers under pressure includes two piezoelectric wafers 109, two pressure blocks 108, The voltage stabilizing circuit 104, the signal conditioning amplifying circuit, the 3.3V low-voltage low-power single-chip microcomputer STC12LE5608AD with A/D conversion function, the wireless transmitting module NRF24L01, and the rectifying circuit are all placed in the placement box. The placement box is connected with the shaft sleeve and rotates synchronously with the shaft sleeve and the main shaft. With the rotation of the main shaft, the piezoelectric wafer is squeezed by the centrifugal force generated by the pressure block in the radial direction of the main shaft, forming two poles with positive and negative charges on the inner and outer sides. After the two piezoelectric chips are connected in series, the positive and negative poles of the two piezoelectric chips are connected to the voltage stabilizing circuit. The output of the voltage stabilizing circuit is respectively connected with the signal conditioning amplifier circuit, the 3.3V low-voltage low-power single-chip microcomputer STC12LE5608AD with A/D conversion function, and the wireless transmitting module NRF24L01 to supply power to them. During the operation of the main shaft and the bushing, when the centrifugal force generated by the pressure block decreases (the reduction of the motor speed or the vibration caused by the friction of the dynamic and static rings), the piezoelectric wafer will return to its original state. At this time, the positive and negative charges inside it As the distance between them becomes larger, a larger polarization intensity appears, which makes the surface of the piezoelectric wafer re-adsorb part of the charges, which also provides conditions for the continuous release of free charges.

It is also within the protection scope of this technology to perform corresponding equivalent replacements on the basis of not changing the functions of each component of this technology patent.

Claims (6)

1. A mechanical seal end face friction torque measurement device based on self-power supply and wireless data transmission, including a shaft sleeve with a U-shaped opening on the same busbar at both ends, a transmission pin connected to the main shaft through the U-shaped opening, a force sensor, and a signal Processor, wireless transmitting module, wireless receiving module, self-powered module; the main shaft passes through the shaft sleeve, the mechanical seal of the end surface friction torque to be measured is fitted on the shaft sleeve, the moving ring is connected to the shaft sleeve, and the static ring is fixed in the sealing chamber It is characterized in that: the torque generated by the dynamic and static rings of the mechanical seal due to end surface friction is balanced with the torque transmitted from the main shaft to the shaft sleeve through the transmission pin; this torque is determined by the force sensor attached to the transmission pin The product of the measured circumferential force and the force arm of the force measuring point is determined. The measured circumferential force is processed by the signal processor and transmitted to the wireless receiving module through the wireless transmitting module; The transmitter and the wireless transmitter module are powered. 2. The mechanical seal end face friction torque measurement device based on self-power supply and wireless data transmission according to claim 1, characterized in that, the self-power supply module includes a magnet fixed outside the sealing chamber, and a coil winding that rotates with the main shaft , rectification circuit and voltage stabilization circuit, the rotating coil winding cuts the magnetic field line to generate induced electromotive force, and then it is processed by the rectification circuit and voltage stabilization circuit to become a stable DC power supply. 3. The mechanical seal end face friction torque measurement device based on self-power supply and wireless data transmission as claimed in claim 2, characterized in that, the end of the shaft sleeve adopts a closed structure to wrap the end of the main shaft, and the end of the shaft sleeve is connected to A placement box is equipped with a signal processor, a wireless transmitting module, a rectification circuit and a voltage stabilization circuit, and the output end of the coil winding is connected with the rectification circuit and the voltage stabilization circuit. 4. The mechanical seal end face friction torque measurement device based on self-power supply and wireless data transmission according to claim 1, characterized in that, the self-power supply module includes a piezoelectric chip that rotates with the main shaft, a pressure block and a voltage stabilization circuit ; When the piezoelectric wafer is squeezed by the pressure block rotating with the main shaft in the radial direction, the distance between the positive and negative charges inside it will decrease, so some of the free charges originally attached to the crystal surface will be released , processed by the voltage regulator circuit to become a stable DC power supply. 5. The mechanical seal end face friction torque measurement device based on self-powered and wireless data transmission as claimed in claim 4, characterized in that, the end of the shaft sleeve adopts a closed structure to wrap the end of the main shaft, and the end of the shaft sleeve is connected to A placement box, with built-in signal processor, wireless transmission module, voltage stabilizing circuit, piezoelectric chip and pressure block; on the inner side of the wafer. 6. The mechanical seal end face friction torque measurement device based on self-power supply and wireless data transmission as claimed in claim 1, characterized in that, between the two ends of the shaft sleeve and the main shaft along the circumferential direction on the cross section of the shaft Place 3 or more balls evenly, respectively.