CN104374660B - Friction wheel wear degree monitoring method - Google Patents

Abstract

The invention provides a method for measuring the degree of wear of a friction wheel applied in a friction wheel transmission system. The measurement system includes three parts: the auxiliary wheel speed measurement module, the driving wheel speed measurement module and the signal processing and transmission module. The auxiliary wheel speed measurement module is mainly composed of an elastic wheel fork that can rotate with a fixed axis, an auxiliary wheel and a proximity switch. The elastic force makes the auxiliary wheel and the friction wheel closely contact and rotate accordingly. Calculated according to the relationship between the contact point linear velocity Obtain the real-time thickness of the friction wheel; the driving wheel speed measurement module is used when the on-site control system cannot provide the friction wheel speed parameter, and the basic principle of its speed measurement is to use a proximity switch to calculate the number of pulse signals in a fixed time; the signal processing transmission of the present invention The module takes the controller as the core, processes and calculates the speed signals of the first two speed measuring modules, and outputs the signals as switch values, standard current signals and serial port signals.

Description

A method for monitoring the wear degree of a friction wheel

technical field

The invention relates to the technical field of friction wheel transmission, in particular to an automatic monitoring method and instrument for the wear degree of friction wheels on a conveying line.

Background technique

Friction wheel transmission is a mechanical transmission method that uses two wheels to directly contact or clamp a mobile platform, and press them together to generate friction to achieve power transmission. It has the advantages of simple mechanical structure, low transmission noise and convenient maintenance, and is widely used in machinery, textile, automobile and logistics industries.

The structure of the friction wheel is generally a material with a large friction coefficient such as steel hub covered with leather, polyurethane or rubber. During long-term use, the thickness of the friction material on the outer layer of the friction wheel gradually decreases, and slippage and unbalanced transmission may occur. Failure of one friction wheel can shut down the entire production line, seriously affecting production schedules. Therefore, it is necessary to monitor the wear degree of the friction wheel in real time and input the signal to the corresponding control system.

At present, the non-contact sensors that can be used to monitor the thickness of the friction wheel are mainly non-contact sensors, including capacitive displacement sensors, eddy current displacement sensors, ultrasonic displacement sensors and laser displacement sensors. The capacitive displacement sensor has a small measurement range, and it is difficult to install rotating parts; the eddy current sensor can only effectively monitor metal parts, and cannot measure non-metallic objects such as polyurethane or rubber; the ultrasonic displacement sensor has a large measurement error for short distances. The precision requirement is high and it is easily affected by the working environment; the laser displacement sensor has strict requirements on the transparency of the measured object, and there are errors in the monitoring results of translucent materials such as polyurethane.

Contents of the invention

Aiming at the defects of the existing non-contact displacement sensor used to monitor the thickness of the friction wheel, the applicant provided an indirect contact displacement monitoring method applied to the thickness of the friction wheel in the transmission system of the friction wheel after research and improvement to solve the problems existing in the current technology. the above-mentioned defects.

Technical scheme of the present invention is as follows:

The invention provides a measurement system for monitoring the wear degree of friction wheels, that is, the thickness of friction materials, which is composed of three parts: an auxiliary wheel speed measurement module, a driving wheel speed measurement module and a signal processing and transmission module. The auxiliary wheel speed measurement module and the driving wheel speed measurement module are respectively connected to the signal processing and transmission module, and the signal processing and transmission module is connected to the control system of the specific application object.

The auxiliary wheel speed measurement module is used to measure the rotation speed of the friction wheel under the condition of real-time change in thickness, and is fixed by the casing, auxiliary wheel, auxiliary wheel sensing contact, auxiliary wheel fork, auxiliary wheel speed measurement proximity switch, wheel fork fixing nut, spring, and wheel Shaft, spring fixing card, upper limit card, lower limit card, signal port, auxiliary wheel protruding hole and casing fixing position. The casing is fixed on the bracket on the application site, and the installation hole of the casing is adjusted to make the auxiliary wheel and the friction wheel under test closely contact; the auxiliary wheel is installed on the auxiliary wheel fork, and the auxiliary wheel fork is connected to the fixed shaft of the wheel fork, and the fixed shaft of the wheel fork is connected to the machine Shell; the auxiliary wheel fork is also connected with the auxiliary wheel speed measuring proximity switch, the auxiliary wheel speed measuring proximity switch is used to monitor the speed of the auxiliary wheel, the auxiliary wheel speed measuring proximity switch is connected to the signal port, and the signal port is fixed on the casing; one end of the spring is connected to the wheel fork The shaft is fixed, and the other end is connected to the auxiliary wheel fork. The spring force causes the auxiliary wheel to generate pressure in the direction of the friction wheel; there are upper limit cards and lower limit cards on both sides of the auxiliary wheel fork, which are fixed on the casing to limit the auxiliary wheel. The range of movement of the fork.

The driving wheel speed measuring module is used to monitor the rotational speed of the friction wheel, and consists of a contact plate, a contact screw, an inductive contact, a proximity switch of the driving wheel speed measuring module, a mounting bracket of the driving wheel speed measuring module, a fixing nut and a bracket fixing screw. The contact plate is installed on the rotating shaft of the friction wheel under test, and a plurality of protruding screws are evenly distributed on the circumference of the contact plate, and metal magnetic induction contacts are installed on the screw rods; the proximity switch of the driving wheel speed measurement module is connected with the mounting bracket of the driving wheel speed measurement module, Installed on one end of the bracket, by adjusting the installation position of the bracket, the proximity switch and the sensing contact of the driving wheel speed measurement module are kept within the measurable range; the installation bracket of the driving wheel speed measurement module is installed on the fixed guide rail on site.

The main function of the signal processing and transmission module is to receive the proximity switch signals of the auxiliary wheel speed measurement module and the driving wheel speed measurement module, process them and convert them into standard transmitter signals. The signal processing and transmission module is composed of a controller, a keyboard circuit, an isolation circuit, a display circuit, a standard signal circuit, a serial communication circuit, a power circuit, related ports and a casing. The controller is the core of signal processing, which is used for the program operation of the received signal; the keyboard circuit is connected to the I/O port of the controller to realize the input of measurement parameters; the output port of the auxiliary wheel speed measurement module and the proximity switch port of the driving wheel speed measurement module are connected Isolation circuit, the isolation circuit is connected to the I/O port of the controller; the controller is also connected to the display circuit, standard signal circuit and serial port communication circuit respectively; the display circuit realizes the display of the operation result; the standard signal circuit performs D/O A conversion, and then further processed into a standard signal of 4-20mA; the serial port communication circuit realizes RS-485 signal conversion. The power supply circuit is used to supply power to the above-mentioned circuits, and the relevant ports realize the input and output of signals, and all the above-mentioned devices are installed in the casing.

The invention calculates the wear degree of the friction wheel by monitoring the thickness of the friction material. In actual implementation, it is necessary to ensure that the auxiliary wheel in the auxiliary wheel speed measurement module is in close contact with the friction wheel in the conveyor line without slipping. In this case, the linear velocity at the contact point of the friction wheel and the auxiliary wheel is the same, and this linear velocity is respectively related to the rotational speed and radius of each wheel. The radius of the friction wheel will gradually decrease with the time of use, and the material of the auxiliary wheel can be properly selected to ensure that its radius is basically constant. Therefore, by measuring the speed of the friction wheel and the auxiliary wheel through the auxiliary wheel speed measurement module and the driving wheel speed measurement module, and then inputting the signal to the signal processing and transmission module, the real-time radius of the friction wheel, that is, the degree of wear, can be calculated.

The beneficial technical effect of the present invention is:

The design of the present invention is based on the modularization mode, and one or more modules can be selected according to the site conditions to realize the required functions in actual use, and it has the characteristics of flexible configuration. If the application site itself has a control system and the friction wheel speed is known, it only needs to configure the auxiliary wheel speed measurement module to realize the thickness measurement of the friction wheel; when the application site itself has a control system but the friction wheel speed is unknown, it is necessary to configure auxiliary Wheel speed measurement module and active wheel speed measurement module; in the case of on-site display and networking, a signal processing and transmission module can be added.

The main component used to realize the measurement task in the present invention is a proximity switch, and the signal form is a switch value pulse, which has the characteristics of high reliability and strong interference ability.

The invention has strong versatility, is not limited by the material of the friction surface of the friction wheel, and can be used in all friction wheel transmission systems.

The invention has a simple structure and has obvious cost advantages compared with the existing non-contact displacement sensor.

Description of drawings

Fig. 1 is a schematic diagram of the main structure and installation of the present invention.

Fig. 2 is a schematic diagram of the structure of the auxiliary wheel speed measuring module of the present invention.

Fig. 3 is a structural diagram of the driving wheel speed measuring module of the present invention.

Fig. 4 is a schematic structure diagram of the signal processing and transmitting module.

[Description of Drawings] 1. Transmission load; 2. Friction wheel; 3. Friction material layer; 4. Transmission motor; 5. Friction wheel shaft; 6. Fixing nut; 7. Auxiliary wheel; Shell; 9. Mounting bracket for auxiliary wheel speed measurement module; 10. On-site fixed bracket; 11. Contact plate; 12. Contact screw; 13. Induction contact; Mounting bracket; 16. Bracket fixing screw; 17. Signal processing and transmission module; 18. Signal processing and transmission module mounting bracket; 19. Auxiliary wheel sensing contact; 20. Auxiliary wheel fork; .Fork fixing nut; 23. Spring; 24. Upper limit card; 25. Wheel fork fixing shaft; 26. Spring fixing card; 27. Signal port; 28. Lower limit card; 29. Housing fixing position; 30. Auxiliary 31. Input A port; 32. Input B port; 33. RS-485 port; 34.4-20mA port; 35. Alarm output port.

detailed description

The specific embodiments of the present invention will be further described below in conjunction with the accompanying drawings.

As shown in FIG. 1 , the present invention includes three parts: an auxiliary wheel speed measurement module 36 , a driving wheel speed measurement module 37 and a signal processing and transmission module 38 , which are respectively installed at suitable positions on the field fixed bracket 10 . The installation position of the auxiliary wheel speed measurement module 36 is parallel to the friction wheel 2. Proper adjustment makes the auxiliary wheel 7 and the friction material layer 3 closely contact; the installation position of the driving wheel speed measurement module 37 is located above the friction wheel 2; the signal processing transmission module 38 is installed It can be adjusted according to the site conditions, based on the convenience of on-site display and connection of input signals. There are two types of ports outside the signal processing and transmission module 38. The input ports include input A port 31 and input B port 32, which are respectively connected to the auxiliary wheel speed measurement module 36. And the proximity switch signal of the driving wheel speed measurement module 37, the output ports include RS-485 port 33, 4-20mA port 34 and alarm output port 35; the transmission motor 4 of the transmission system is connected to the friction wheel 2, the friction material layer 3 and the transmission load 1 In close contact, the rotation of the friction wheel 2 drives the transmission load 1 to move, and the friction material layer 3 wears out gradually over time, thereby causing the radius of the friction wheel 2 to decrease.

See Fig. 2, the auxiliary wheel speed measurement module of the present invention includes auxiliary wheel 7, sensing contact 19, auxiliary wheel fork 20, proximity switch 21, wheel fork fixing nut 22, spring 23, upper limit card 24, wheel fork fixing shaft 25, spring Fixed card 26, signal port 27, lower limit card 28, casing fixed position 29, auxiliary wheel protruding hole 30, casing 8 and mounting bracket 9. The casing 8 is fixed on the mounting bracket 9 by the casing fixing position 29, and the mounting bracket 9 is connected to the field fixing bracket 10; the auxiliary wheel 7 is connected to the auxiliary wheel fork 20, and the auxiliary wheel fork 20 is connected to the wheel fork fixing shaft 25, and the wheel fork fixing nut 22 Used to fix the auxiliary wheel fork 20, the auxiliary wheel fork 20 can be rotated at the center of the circle with the wheel fork fixing shaft 25; the upper limit card 24 and the lower limit card 28 are fixed on the casing 8, and its function is to make the auxiliary wheel fork 20 within a safe range Movement; the auxiliary wheel fork 20 is also connected with a spring 23, one end of the spring 23 is stuck on the auxiliary wheel fork 20, and the other end is stuck on the spring fixing card 26, and the elasticity of the spring 23 makes the auxiliary wheel fork 20 produce a hole extending toward the auxiliary wheel Power in the direction of 30; the auxiliary wheel 7 is equipped with a metal magnetic induction contact 19, and the corresponding induction contact 19 direction on the auxiliary wheel fork 20 is also connected with a proximity switch 21. The rotation of the auxiliary wheel 7 can make the proximity switch 21 generate a pulse signal. One end of the proximity switch 21 is connected to the signal port 27 .

3 , the driving wheel speed measurement module of the present invention is composed of a fixed nut 6 , a contact plate 11 , a contact screw 12 , an inductive contact 13 , a proximity switch 14 , a mounting bracket 15 and a fixing screw 16 . The contact plate 11 is connected to the friction wheel rotating shaft 5, and fixed with the fixing nut 6, and rotates synchronously with the friction wheel 2; the contact plate 11 is evenly distributed with contact screws 12 on the circumference, and the induction contacts 13 are metal magnetic materials, which are connected to the contact screw 12; there is a proximity switch 14 above the sensing contact 13, which is fixed on one end of the mounting bracket 15, and the other end of the mounting bracket 15 is installed on the field support 10 by a fixing screw 16; the sensing contact 13 contact plate 11 rotates, and simultaneously approaches The switch 14 generates a pulse signal, and the cable of the proximity switch 14 is connected to the input B port 32 of the signal processing and transmission module 38.

As shown in Fig. 4, the signal processing and transmission module of the present invention is mainly composed of a controller, a keyboard circuit, a signal isolation circuit, an alarm signal circuit, a display circuit, a standard signal circuit, a serial communication circuit, a power supply circuit and the like. In the figure, input A is connected to the signal port 27 of the auxiliary wheel speed measurement module, and input B is connected to the proximity switch signal of the driving wheel speed measurement module. The two signals are isolated by the optocoupler and then input to the controller; the controller calculates the number of pulses in one second through programming The rotational speed n _m of the friction wheel 2 and the rotational speed n _f of the auxiliary wheel 7 can be obtained. Because the two wheels are in close contact, the linear velocity V at the contact point is the same, and the relational formula is:

V=2πr _m n _m =2πr _f n _f

Where r _m and r _f are the radius of the friction wheel 2 and the radius of the auxiliary wheel 7 respectively. As the passive wheel, the auxiliary wheel 7 has little contact pressure with the friction wheel 2, and the selected material has a high wear resistance coefficient, so it can be considered that r _f is a constant value, then the real-time radius of the friction wheel 2 is:

Thus, the degree of wear of the friction wheel 2 can be known.

As shown in Figure 4, the main function of the keyboard circuit is to input parameters such as the maximum radius, the minimum radius, and the alarm limit of the friction wheel 2; the alarm signal circuit performs an alarm according to the set alarm upper and lower limits, and its signal output format is a switch value; the standard signal circuit will The signal calculated and output by the controller is converted into a standard signal of 4-20mA through digital-to-analog conversion and signal transmission to meet the needs of a general-purpose instrument; the serial port communication circuit converts the serial port signal of the controller into an RS signal commonly used in industrial processes. -485 signal for network use; the display circuit is used as a man-machine interface to process the recognition of keyboard input signals and the on-site display of measurement signals.

Claims (2)

1. A measuring system applied to friction wheel wear degree in a conveying system driven by friction wheels, characterized in that: it includes an auxiliary wheel speed measurement module (36), a driving wheel speed measurement module (37) and a signal processing and transmission module (38) Three parts, the signal port (27) of the auxiliary wheel speed measurement module (36) is connected to the input A port (31) of the signal processing and transmission module (38), and the proximity switch (14) of the driving wheel speed measurement module is connected to the signal processing and transmission module (38) ) of the input B port (32), the signal processing and transmission module (38) is also connected to the RS-485 port (33), the 4-20mA port (34) and the alarm output port (35); the training wheel speed measurement module (36) includes Auxiliary wheel (7), auxiliary wheel sensing contact (19), auxiliary wheel fork (20), auxiliary wheel speed measuring proximity switch (21), wheel fork fixing nut (22), spring (23), wheel fork fixing shaft (25 ), spring fixing card (26), upper limit card (24), lower limit card (28), signal port (27), casing (8), auxiliary wheel extension hole (30) and casing fixing position (29 ); the auxiliary wheel (7) circumference distribution is connected with the auxiliary wheel induction contact (19), the auxiliary wheel (7) axis is connected with the auxiliary wheel fork (20), and the auxiliary wheel fork (20) is connected with the auxiliary wheel speed measuring proximity switch (21) And spring (23), one end of spring (23) is connected with spring fixing card (26), and the other end is fixed on the auxiliary wheel fork (20), and auxiliary wheel fork (20) is also connected with wheel fork fixing shaft (25), and wheel fork is fixed Shaft (25), spring fixed card (26), upper limit card (24), lower limit card (28) and auxiliary wheel protruding hole (30) are all connected with casing (8); driving wheel speed measuring module (37 ) includes a contact plate (11), a contact screw (12), an inductive contact (13), a drive wheel speed measurement module proximity switch (14), a drive wheel speed measurement module mounting bracket (15), a fixing nut (6) and a bracket Fixing screws (16); the circumference of the contact plate (11) is respectively connected to a plurality of contact screw rods (12), the contact screw rods (12) are connected to the sensing contacts (13), and one end of the driving wheel speed measurement module mounting bracket (15) is connected to The driving wheel speed measurement module is close to the switch (14), and the other end is fixed on the field support; the contact plate (11) is connected with the friction wheel (2) on the spot, and fixed with a fixing nut (6). 2. a kind of measuring method that is applied to the measurement system of friction wheel wear degree in the conveying system of friction wheel transmission as claimed in claim 1, is characterized in that: 1) Use the indirect contact method to convert the thickness or displacement monitoring of the friction wheel into the speed monitoring, and then calculate the real-time thickness value of the friction wheel according to the principle of constant linear velocity; 2) Use elastic forks to connect the auxiliary wheel and contact with the on-site friction wheel to ensure that the friction wheel can still be in close contact with the auxiliary wheel after the radius is reduced, so that the linear speed constant condition is always established; 3) In the system where the rotational speed of the friction wheel cannot be known, the sensing contacts are arranged in the form of a contact plate, and the sensing contacts are made of metal magnetic materials. When the installation conditions permit, the sensing contacts can be directly fixed on the hub of the friction wheel by magnetic force superior; 4) The entire measurement system includes three parts: the auxiliary wheel speed measurement module, the driving wheel speed measurement module and the signal processing and transmission module. Each part is related to each other and independent of each other, and can be reasonably selected according to the site situation; 5) The signal processing and transmission module includes standard current signals, switch signals and serial signal ports, which meet the requirements of general instruments.