CN112781771A - Non-contact sound wave type belt tension measuring device and method - Google Patents

Non-contact sound wave type belt tension measuring device and method Download PDF

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Publication number
CN112781771A
CN112781771A CN202110068070.0A CN202110068070A CN112781771A CN 112781771 A CN112781771 A CN 112781771A CN 202110068070 A CN202110068070 A CN 202110068070A CN 112781771 A CN112781771 A CN 112781771A
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China
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circuit
resistor
capacitor
sound wave
belt
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Chinese (zh)
Inventor
李德明
李玉英
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Guangxi Normal University
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Guangxi Normal University
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    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01L—MEASURING FORCE, STRESS, TORQUE, WORK, MECHANICAL POWER, MECHANICAL EFFICIENCY, OR FLUID PRESSURE
    • G01L5/00—Apparatus for, or methods of, measuring force, work, mechanical power, or torque, specially adapted for specific purposes
    • G01L5/04—Apparatus for, or methods of, measuring force, work, mechanical power, or torque, specially adapted for specific purposes for measuring tension in flexible members, e.g. ropes, cables, wires, threads, belts or bands
    • G01L5/042—Apparatus for, or methods of, measuring force, work, mechanical power, or torque, specially adapted for specific purposes for measuring tension in flexible members, e.g. ropes, cables, wires, threads, belts or bands by measuring vibrational characteristics of the flexible member
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01L—MEASURING FORCE, STRESS, TORQUE, WORK, MECHANICAL POWER, MECHANICAL EFFICIENCY, OR FLUID PRESSURE
    • G01L5/00—Apparatus for, or methods of, measuring force, work, mechanical power, or torque, specially adapted for specific purposes
    • G01L5/04—Apparatus for, or methods of, measuring force, work, mechanical power, or torque, specially adapted for specific purposes for measuring tension in flexible members, e.g. ropes, cables, wires, threads, belts or bands
    • G01L5/10—Apparatus for, or methods of, measuring force, work, mechanical power, or torque, specially adapted for specific purposes for measuring tension in flexible members, e.g. ropes, cables, wires, threads, belts or bands using electrical means

Abstract

The invention discloses a non-contact sound wave type belt tension measuring device and a non-contact sound wave type belt tension measuring method, wherein a capacitor electret microphone MK1 is used as a sound wave sensor, and the sound wave sensor is output to a single chip microcomputer circuit through a signal acquisition circuit, a triode amplification circuit, a low-pass filter circuit, an operational amplification circuit and a signal shaping circuit in sequence. Compare the tradition and adopt direct contact tension measurement mode can obviously reduce detection device to the influence of the belt tension measurement accuracy degree of awaiting measuring, and it is high to detect the belt tension precision of awaiting measuring simultaneously, measures the swift convenience of operation, and measurement efficiency is high-efficient, and circuit structure is with low costs, instrument long service life, and it is convenient to maintain, the sexual valence relative altitude.

Description

Non-contact sound wave type belt tension measuring device and method
Technical Field
The invention relates to the technical field of tension measurement of a belt to be measured, in particular to a non-contact sound wave type belt tension measuring device and method.
Background
The transmission of the belt to be tested is to use a tensioned (annular) belt to be tested to be sleeved on the belt pulleys to be tested of the two transmission shafts, and the power of one shaft is transmitted to the other shaft by means of the friction force generated when the belt to be tested and the belt pulleys to be tested are tensioned. In the power transmission conversion process, a belt to be measured is an important transmission component, and the tension of the belt to be measured when the belt to be measured is tensioned is an important parameter. In a machine driven by a belt to be measured, in order to guarantee the service life of the belt to be measured and a transmission system, proper tension needs to be guaranteed at the beginning of driving the belt to be measured, and the loads of all the belts to be measured in the same transmission system need to be kept consistent. The excessive tightening of the belt to be measured can strengthen the pressure which is not to be born for the shaft and the bearing, lead to the premature wear of the shaft and the bearing, and can also cause the noise of an engine; if the belt to be measured is too loose, the belt to be measured can cause slipping, the transmission efficiency is too low, and damage to engine parts can be caused. If at automobile engine belt transmission in-process that awaits measuring, the belt transmission's that awaits measuring main trouble is just skidding, causes the reason of skidding mainly to await measuring the belt and loosens, causes frictional force to be less than the resistance to cause transmission efficiency to reduce and can not keep accurate drive ratio (the ratio of the revolution per minute of action wheel to the revolution per minute of following driving wheel). In order to reduce the rotation fault of the belt to be measured of the automobile, ensure the stable operation of the automobile, reduce the vibration impact and ensure the stable transmission, it is important to accurately measure the tension of the belt to be measured of the automobile.
The belt tensiometer to be measured is a tool for measuring the tension of the belt to be measured, wherein the belt tensiometer to be measured commonly used is a contact type belt tensiometer to be measured. The contact belt tensiometer that awaits measuring and the belt direct contact that awaits measuring can bring the error for tension detection because of frictional force certainly to long-time contact belt that awaits measuring of sensing device can cause the wearing and tearing of instrument contact part, has reduced testing arrangement's precision and life-span, and consequently the contact measurement effect is not good, and the precision is lower. In addition, the contact type to-be-measured belt tensiometer also has the problems of troublesome installation of the measuring device, limited space, low measuring efficiency, large signal acquisition error and the like.
Disclosure of Invention
The invention aims to solve the problems of troublesome installation and low measurement precision of a contact type to-be-measured belt tensiometer and provides a non-contact acoustic wave type belt tension measuring device and method.
In order to solve the problems, the invention is realized by the following technical scheme:
a non-contact sound wave type belt tension measuring device mainly comprises a sound wave sensor and a tension measuring instrument; the tension measuring instrument comprises a sound wave parameter detection circuit, a keyboard input circuit, a liquid crystal display circuit and a single chip microcomputer circuit; the output end of the sound wave sensor is connected with the input end of the sound wave parameter detection circuit, and the output end of the sound wave parameter detection circuit is connected with the input end of the single chip microcomputer circuit; the output end of the keyboard input circuit is connected with the input end of the singlechip circuit; the output end of the single chip circuit is connected with the input end of the liquid crystal display circuit; the sound wave parameter detection circuit consists of an audio signal acquisition circuit, a triode amplification circuit, a low-pass filter circuit, an operational amplification circuit and a signal shaping circuit; the input end of the audio signal acquisition circuit forms the input end of the sound wave parameter detection circuit; the audio signal acquisition circuit is connected with the input end of the low-pass filter circuit through the triode amplification circuit, the output end of the low-pass filter circuit is connected with the input end of the signal shaping circuit through the operational amplification circuit, and the output end of the signal shaping circuit forms the output end of the sound wave parameter detection circuit.
As an improvement, the non-contact sound wave type belt tension measuring device is also provided with a poking rod for poking the belt to be measured.
In the scheme, the acoustic wave sensor is a capacitor electret microphone MK 1; the positive electrode of the electret condenser microphone MK1 forms the output end of the acoustic wave sensor, and the negative electrode of the electret condenser microphone MK1 is grounded to GND.
In the scheme, the audio signal acquisition circuit comprises capacitors C1-C2 and a resistor R1; one end of the resistor R1, one end of the capacitor C1 and one end of the capacitor C2 form the input end of the audio signal acquisition circuit; the negative electrode of the acoustic wave sensor is grounded GND; the other end of the resistor R1 is connected with a power supply VCC; the other end of the capacitor C1 is grounded GND; the other end of the capacitor C2 forms the output end of the audio signal acquisition circuit.
In the scheme, the triode amplifying circuit comprises a triode Q1, a triode Q2, a capacitor C3 and resistors R2-R6; the base electrode of the triode Q1 is connected with one end of the resistor R5 to form the input end of the triode amplifying circuit; an emitter of the triode Q1 is connected with one end of the resistor R4; the collector of the triode Q1 is connected with one end of the resistor R2 and the base of the triode Q2; an emitter of the triode Q2 is connected with the other end of the resistor R5, one end of the resistor R6 and one end of the capacitor C3; the collector of the triode Q2 is connected with one end of a resistor R3; the other end of the resistor R4, the other end of the resistor R6 and the other end of the capacitor C3 are grounded GND; the other end of the resistor R2 and the other end of the resistor R3 are connected with a power supply VCC; the collector of transistor Q2 forms the output of the transistor amplification circuit.
In the scheme, the low-pass filter circuit comprises capacitors C4-C6 and resistors R7-R10; one end of the capacitor C4 is connected with one end of the resistor R7 to form the input end of the low-pass filter circuit; the other end of the resistor R7 is connected with one end of a resistor R8 and one end of a capacitor C5; the other end of the capacitor C5 is connected with one end of a resistor R9, one end of a resistor R10 and one end of a capacitor C6; the other end of the capacitor C4, the other end of the resistor R8, the other end of the resistor R9 and the other end of the capacitor C6 are grounded to GND; the other end of the resistor R10 forms the output end of the low-pass filter circuit.
In the above scheme, the operational amplifier circuit includes an operational amplifier U1, capacitors C7-C9, and a resistor R11-a resistor R14; one end of the capacitor C7 is connected with the No. 2 pin of the operational amplifier U1 to form the input end of the operational amplifier circuit; the other end of the capacitor C7 is connected with the 1 st pin and the 6 th pin of the operational amplifier U1; one end of the resistor R11 is connected with the 3 rd pin of the operational amplifier U1, and the other end of the resistor R11 is grounded; one end of the resistor R12 is connected with the 5 th pin of the operational amplifier U1, and the other end of the resistor R12 is connected with a power supply VCC; one end of the capacitor C8 is connected with a power supply VCC, and the other end of the capacitor C8 is grounded; one end of the capacitor C9, one end of the resistor R13 and one end of the resistor R14 are connected with the 5 th pin of the operational amplifier U1; the other end of the capacitor C9 and the other end of the resistor R13 are grounded GND; the positive power supply end, namely the 4 th pin, of the operational amplifier U1 is connected with a power supply VCC, and the negative power supply end, namely the 11 th pin, of the operational amplifier U1 is connected with the GND; the other end of the resistor R14 is connected with the 7 th pin of the operational amplifier U1 to form the output end of the operational amplifier circuit.
In the scheme, the signal shaping circuit comprises a digital logic chip U2A and resistors R15-R16; one end of the resistor R15 forms the input end of the signal shaping circuit; the other end of the resistor R15 is connected with the input end of the digital logic chip U2A, and the output end of the digital logic chip U2A is connected with one end of the resistor R16; and the resistor R16 is arranged at the other end of the output end of the signal shaping circuit.
The non-contact sound wave type belt tension measuring method realized by the device specifically comprises the following steps:
step 1, arranging an acoustic wave sensor near a belt to be measured in a non-contact manner;
step 2, shifting the belt to be measured to vibrate the belt to send out sound waves, and sensing vibration sound wave signals by a sound wave sensor and sending the signals to a tension measuring instrument;
step 3, an audio signal acquisition circuit of the tension measuring instrument acquires vibration sound wave signals, and the vibration sound wave signals are sent to a single chip microcomputer circuit after being sequentially subjected to first amplification of a triode amplification circuit, filtering of a low-pass filter circuit, secondary amplification of an operational amplification circuit and shaping of a signal shaping circuit;
step 4, processing the input vibration sound wave signal by a single chip microcomputer circuit of the tension measuring instrument to obtain the natural vibration frequency of the belt to be measured, and calculating the tension of the belt to be measured according to the natural vibration frequency of the belt to be measured;
To＝4×M×W×S2×f2×10-9
in the formula, To is the tension of the belt To be measured, M is the unit mass of the belt To be measured, W is the width of the belt To be measured, S is the tangent length of the belt To be measured, and f is the natural vibration frequency of the belt To be measured.
Compared with the prior art, the invention adopts the capacitor electret microphone MK1 as the sound wave sensor, and the sound wave sensor is output to the singlechip circuit through the signal acquisition circuit, the triode amplification circuit, the low-pass filter circuit, the operational amplification circuit and the signal shaping circuit in sequence. Compare the tradition and adopt direct contact tension measurement mode can obviously reduce detection device to the influence of the belt tension measurement accuracy degree of awaiting measuring, and it is high to detect the belt tension precision of awaiting measuring simultaneously, measures the swift convenience of operation, and measurement efficiency is high-efficient, and circuit structure is with low costs, instrument long service life, and it is convenient to maintain, the sexual valence relative altitude.
Drawings
Fig. 1 is a schematic structural view of a noncontact acoustic wave type belt tension measuring apparatus.
Fig. 2 is a schematic block diagram of a tension measuring instrument.
Fig. 3 is a schematic diagram of an acoustic parameter measurement circuit.
Reference numbers in the figures: 1. a belt to be tested; 2. a toggle bar; 3. an acoustic wave sensor; 4. and a tension measuring instrument.
Detailed Description
In order to make the objects, technical solutions and advantages of the present invention more apparent, the present invention is further described in detail below with reference to specific examples.
A non-contact sound wave type belt tension measuring device is mainly composed of a poking rod 2, a sound wave sensor 3 and a tension measuring instrument 4, as shown in figure 1. The stirring rod 2 is used for stirring the belt 1 to be tested, so that the belt 1 to be tested generates vibration sound waves. In this embodiment the toggle bar 2 is a metal bar. The sound wave sensor 3 is arranged near the stirring rod 2 and close to the belt 1 to be measured and is used for collecting vibration sound wave signals. In the present embodiment, the acoustic wave sensor 3 is the electret condenser microphone MK1, the positive electrode of the electret condenser microphone MK1 forms the output terminal of the acoustic wave sensor 3, and the negative electrode of the electret condenser microphone MK1 is grounded to GND. The acoustic wave sensor 3 is electrically connected with the tension measuring instrument 4, and the tension measuring instrument 4 processes and displays the vibration acoustic wave signals collected by the acoustic wave sensor 3.
The tension measuring instrument 4 comprises a power circuit, a sound wave parameter detecting circuit, a keyboard input circuit, a liquid crystal display circuit and a single chip microcomputer circuit, as shown in fig. 2. The power supply circuit supplies power to the respective circuits of the tension measuring instrument 4. The output end of the sound wave sensor 3 is connected with the input end of the sound wave parameter detection circuit, and the output end of the sound wave parameter detection circuit is connected with the input end of the single chip microcomputer circuit, namely the counting pin, so that frequency measurement is realized. The output end of the keyboard input circuit is connected with the input end of the singlechip circuit, so that the input of manual control signals, the on-off control and the like are realized. The output end of the single chip circuit is connected with the input end of the liquid crystal display circuit, and the measurement result, the working state display of the device and the like are achieved.
The sound wave parameter detection circuit comprises an audio signal acquisition circuit, a triode amplification circuit, a low-pass filter circuit, an operational amplification circuit and a signal shaping circuit, as shown in fig. 3. The input end of the audio signal acquisition circuit forms the input end of the sound wave parameter detection circuit. The audio signal acquisition circuit is connected with the input end of the low-pass filter circuit through the triode amplification circuit, the output end of the low-pass filter circuit is connected with the input end of the signal shaping circuit through the operational amplification circuit, and the output end of the signal shaping circuit forms the output end of the sound wave parameter detection circuit.
The signal acquisition circuit comprises capacitors C1-C2 and a resistor R1. In the present embodiment, the capacitor C1 is a ceramic capacitor, the capacitor C2 is a tantalum capacitor, and the resistor R1 is a fixed resistor. One end of the resistor R1, one end of the capacitor C1 and one end of the capacitor C2 form the input end of the audio signal acquisition circuit; the negative electrode of the acoustic wave sensor 3 is grounded GND; the other end of the resistor R1 is connected with a power supply VCC; the other end of the capacitor C1 is grounded GND; the other end of the capacitor C2 forms the output end of the audio signal acquisition circuit. The capacitor electret microphone MK1 adopts a field effect tube as an internal structure, the anode is a D pole, a pull-up resistor R1 provides D pole current for the field effect tube, the capacitor electret microphone MK1 receives vibration sound signals of the belt 1 to be measured and then converts the vibration sound signals into low-frequency electric signals, a capacitor C2 isolates direct current signals, and high-frequency interference signals are filtered by the capacitor C1 through alternating current signals.
The triode amplifying circuit comprises an NPN type triode Q1, an NPN type triode Q2, a capacitor C3 and resistors R2-R6. In this embodiment, the NPN transistor Q1 is of type S8050, the NPN transistor Q2 is of type 9013, the capacitor C3 is a tantalum capacitor, the resistors R2 and R3 are fixed resistors, and the resistor R5 is a feedback resistor. The base electrode of the triode Q1 is connected with one end of the resistor R5 to form the input end of the triode amplifying circuit; an emitter of the triode Q1 is connected with one end of the resistor R4; the collector of the triode Q1 is connected with one end of the resistor R2 and the base of the triode Q2; an emitter of the triode Q2 is connected with the other end of the resistor R5, one end of the resistor R6 and one end of the capacitor C3; the collector of the triode Q2 is connected with one end of a resistor R3; the other end of the resistor R4, the other end of the resistor R6 and the other end of the capacitor C3 are grounded GND; the other end of the resistor R2 and the other end of the resistor R3 are connected with a power supply VCC; the collector of transistor Q2 forms the output of the transistor amplification circuit. NPN type triodes Q1, Q2 play a sound signal amplification role, and resistance R2, R3 are triode collector load resistance, and resistance VCC provides a working voltage for the triode in termination, and resistance R2, R3 function triode CE return circuit alternating current signal change alternating current voltage signal into. Resistor R4 is the emitter feedback resistor of transistor Q1, resistor R6 is the emitter feedback resistor of transistor Q2, and resistor R5 is the feedback resistor between the emitter of transistor Q2 and the base of transistor Q1The feedback resistor mainly acts to inhibit the transistor hEFDispersity of (2) and VBEThe emitter current changes due to the temperature change of (2). Capacitor C3 is a bypass capacitor for the emitter of transistor Q2 and is used to increase the gain of the ac signal. An emitter of the NPN type triode Q1 is connected to a base of the Q2 to form a triode two-stage cascade amplifying circuit, and the signal amplifying effect is enhanced.
The low-pass filter circuit comprises capacitors C4-C6 and resistors R7-R10. In this embodiment, the capacitors C4 and C6 are ceramic capacitors, the capacitor C5 is a tantalum capacitor, and the resistors R7, R8 and R9 are filter resistors. One end of the capacitor C4 is connected with one end of the resistor R7 to form the input end of the low-pass filter circuit; the other end of the resistor R7 is connected with one end of a resistor R8 and one end of a capacitor C5; the other end of the capacitor C5 is connected with one end of a resistor R9, one end of a resistor R10 and one end of a capacitor C6; the other end of the capacitor C4, the other end of the resistor R8, the other end of the resistor R9 and the other end of the capacitor C6 are grounded to GND; the other end of the resistor R10 forms the output end of the low-pass filter circuit. The capacitor C4 has small capacity and is used for filtering high-frequency signals and inhibiting high-frequency interference. The resistor R7 and the resistor R8 form a voltage division circuit, the filtering effect can be improved by increasing the resistance of the resistor, but the resistance of the resistor is not too large, otherwise, the direct current output voltage is reduced. The capacitor C5 and the resistor R9 form an RC high-pass filter circuit, and the capacitance value of C5 is large, so that the actual effect is that frequency signals of several hertz can pass through, the effect of isolating direct current signals and passing alternating current signals is mainly achieved, the capacitor C6 and the resistor R10 form an RC low-pass filter circuit, and the capacitor C4 is small in capacity and further filters high-frequency signals. The filter circuit is designed to pass low frequency vibration sound signals of 5Hz to 800 Hz.
The operational amplifier circuit comprises an operational amplifier U1, capacitors C7-C9 and a resistor R11-resistor R14. In the present embodiment, the operational amplifier U1 is of type MC3403, and the capacitors C7, C8 and C9 are all ceramic capacitors. One end of the capacitor C7 is connected with the No. 2 pin of the operational amplifier U1 to form the input end of the operational amplifier circuit; the other end of the capacitor C7 is connected with the 1 st pin and the 6 th pin of the operational amplifier U1; one end of the resistor R11 is connected with the 3 rd pin of the operational amplifier U1, and the other end of the resistor R11 is grounded; one end of the resistor R12 is connected with the 5 th pin of the operational amplifier U1, and the other end of the resistor R12 is connected with a power supply VCC; one end of the capacitor C8 is connected with a power supply VCC, and the other end of the capacitor C8 is grounded; one end of the capacitor C9, one end of the resistor R13 and one end of the resistor R14 are connected with the 5 th pin of the operational amplifier U1; the other end of the capacitor C9 and the other end of the resistor R13 are grounded GND; the positive power supply end, namely the 4 th pin, of the operational amplifier U1 is connected with a power supply VCC, and the negative power supply end, namely the 11 th pin, of the operational amplifier U1 is connected with the GND; the other end of the resistor R14 is connected with the 7 th pin of the operational amplifier U1 to form the output end of the operational amplifier circuit. The input signal is applied to the 2-pin inverting input of the integrated operational amplifier U1, and a deep negative feedback is introduced back between the 1-pin output and the 2-pin inverting input through the capacitor C7, thereby forming a basic integrating circuit. And the access resistor R11 at the 2-pin non-inverting input end of the integrated operational amplifier U1 is used for balancing the resistance of the two input ends of the integrated operational amplifier to the ground. The resistor R10, the resistor R11, the capacitor C7 and the operational amplifier U1 form an operational amplifier integrating circuit, and are used for converting an analog signal with large ripples and unsmooth into a stable waveform signal after passing through the integrating circuit and playing a role in signal amplification. And two ends of the capacitor C8 are connected with power supplies VCC and GND to play a role in power supply filtering. The resistor R12, the resistor R13, the resistor R14, the capacitor C9 and the operational amplifier U1 form an inverting hysteresis comparator circuit, a feedback network resistor R14 is added between the 7-pin output of the U1 and the 5-pin positive input of the U1 to form positive feedback, the resistor R12 and the resistor R13 form a voltage division circuit to provide reference voltage of the comparator, and the capacitor C9 plays a role in filtering and improves the anti-interference capability of the circuit. The sound vibration signal passes through the integrating circuit and then enters the hysteresis comparator circuit for processing, and a stable pulse signal is output.
The signal shaping circuit comprises a digital logic chip U2A and resistors R15-R16. In the present embodiment, the digital logic chip U2A has model number SN74HC 14. One end of the resistor R15 forms the input end of the signal shaping circuit; the other end of the resistor R15 is connected with the input end of the digital logic chip U2A, and the output end of the digital logic chip U2A is connected with one end of the resistor R16; and the resistor R16 is arranged at the other end of the output end of the signal shaping circuit. The digital logic chip U2A is a Schmitt trigger, plays a role in signal shaping, is used for steepening non-steep rising edges and falling edges in input signals, and is used for shaping output signals which are TTL level signals and are compatible with the TTL level of a single chip microcomputer pin. Digital logic chip U2A has pin 1 forming its input and pin 2 forming its output. The resistor R15 has a small resistance value, and is used for isolating the 7 th pin output of the operational amplifier U1 from the 1 st pin of the digital logic chip U2A, and has the function of suppressing self-oscillation of the circuit. The resistance of the resistor R16 is small, and the function is to isolate the output of the 2 nd pin of the digital logic chip U2A from the circuit of the rear-stage singlechip.
The belt to be measured 1 tensiometer is arranged on various types of belts to be measured 1 between the gear (sliding) wheel shafts, and when the belts to be measured 1 are applied to impact (collision), the belt to be measured 1 in the original static state can generate two irregular aiming waveforms including a high-level component and an impact component at the initial stage and then gradually attenuate into a regular waveform. When a force is applied to the belt 1 to be tested, the belt 1 to be tested initially vibrates in a plurality of modes, but the high-frequency vibration is attenuated faster than the fundamental-frequency vibration, so that the continuous sine wave retained corresponds to the tension of the belt 1 to be tested. After the sound wave sensor 3 samples the sound wave change of the belt 1 to be measured, the single chip microcomputer circuit measures the natural vibration frequency of the belt 1 to be measured. Since the natural vibration frequency of the belt 1 to be measured is positively correlated with the tension value, the basic relationship is that the tension of the belt 1 to be measured is directly proportional to the square of the natural vibration frequency. In addition, the natural vibration frequency is also related to the geometric dimensions such as the width, thickness and length of the belt 1 to be measured. In order to calculate the tension of the belt 1 to be measured, the system uses a transverse vibrating string theory, and needs to input the unit mass, tangent length and width of the belt 1 to be measured, and calculate the actual tension value of the belt 1 to be measured.
The non-contact sound wave type belt tension measuring method realized by the device specifically comprises the following steps:
step 1, aligning a measuring head of an acoustic wave sensor 3 to a belt 1 to be measured, wherein the distance between the measuring head and the belt 1 to be measured is about 110mm, and the measuring head does not contact the belt 1 to be measured;
step 2, knocking the belt 1 to be measured by using the poking rod 2 to enable the belt to be measured to vibrate to send out sound waves, and sending vibration sound wave signals to the tension measuring instrument 4 by the sound wave sensor 3;
step 3, an audio signal acquisition circuit of the tension measuring instrument 4 acquires vibration sound wave signals, and the vibration sound wave signals are sent to a single chip microcomputer circuit after being sequentially subjected to first amplification of a triode amplification circuit, filtering of a low-pass filter circuit, secondary amplification of an operational amplification circuit and shaping of a signal shaping circuit;
step 4, the single chip microcomputer circuit of the tension measuring instrument 4 processes the input vibration sound wave signal, the processing method can adopt the existing method to obtain the natural vibration frequency of the belt 1 to be measured, and the tension of the belt 1 to be measured is calculated according to the natural vibration frequency of the belt 1 to be measured;
To＝4×M×W×S2×f2×10-9
in the formula, To is the tension (N) of the belt 1 To be measured, M is the unit mass (g/1M length × 1mm) of the belt 1 To be measured, W is the width (mm) of the belt 1 To be measured, S is the tangent length (mm) of the belt 1 To be measured, and f is the natural vibration frequency (Hz) of the belt 1 To be measured.
The vibration natural vibration frequency of the belt 1 to be measured is measured, the frequency unit is HZ, and the frequency unit is converted into units of Newton, kilogram force and the like for display after being calculated by a tension calculation formula.
It should be noted that, although the above-mentioned embodiments of the present invention are illustrative, the present invention is not limited thereto, and thus the present invention is not limited to the above-mentioned embodiments. Other embodiments, which can be made by those skilled in the art in light of the teachings of the present invention, are considered to be within the scope of the present invention without departing from its principles.

Claims (9)

1. A non-contact sound wave type belt tension measuring device is characterized by mainly comprising a sound wave sensor (3) and a tension measuring instrument (4);
the tension measuring instrument (4) comprises a sound wave parameter detection circuit, a keyboard input circuit, a liquid crystal display circuit and a single chip microcomputer circuit; the output end of the sound wave sensor (3) is connected with the input end of the sound wave parameter detection circuit, and the output end of the sound wave parameter detection circuit is connected with the input end of the single chip microcomputer circuit; the output end of the keyboard input circuit is connected with the input end of the singlechip circuit; the output end of the single chip circuit is connected with the input end of the liquid crystal display circuit;
the sound wave parameter detection circuit consists of an audio signal acquisition circuit, a triode amplification circuit, a low-pass filter circuit, an operational amplification circuit and a signal shaping circuit; the input end of the audio signal acquisition circuit forms the input end of the sound wave parameter detection circuit; the audio signal acquisition circuit is connected with the input end of the low-pass filter circuit through the triode amplification circuit, the output end of the low-pass filter circuit is connected with the input end of the signal shaping circuit through the operational amplification circuit, and the output end of the signal shaping circuit forms the output end of the sound wave parameter detection circuit.
2. A non-contact acoustic wave type belt tension measuring device as claimed in claim 1, further provided with a poking bar (2) for poking the belt (1) to be measured.
3. A non-contact acoustic wave type belt tension measuring device as claimed in claim 1, wherein the acoustic wave sensor (3) is a condenser electret microphone MK 1; the positive electrode of the capacitor electret microphone MK1 forms the output end of the acoustic wave sensor (3), and the negative electrode of the capacitor electret microphone MK1 is grounded to GND.
4. A non-contact acoustic wave-type belt tension measuring device as claimed in claim 1, wherein the audio signal pickup circuit includes capacitors C1-C2 and a resistor R1;
one end of the resistor R1, one end of the capacitor C1 and one end of the capacitor C2 form the input end of the audio signal acquisition circuit; the negative electrode of the acoustic wave sensor (3) is grounded GND; the other end of the resistor R1 is connected with a power supply VCC; the other end of the capacitor C1 is grounded GND; the other end of the capacitor C2 forms the output end of the audio signal acquisition circuit.
5. A non-contact acoustic wave type belt tension measuring device as claimed in claim 1, wherein the triode amplifying circuit includes a triode Q1, a triode Q2, a capacitor C3, and resistors R2-R6;
the base electrode of the triode Q1 is connected with one end of the resistor R5 to form the input end of the triode amplifying circuit; an emitter of the triode Q1 is connected with one end of the resistor R4; the collector of the triode Q1 is connected with one end of the resistor R2 and the base of the triode Q2; an emitter of the triode Q2 is connected with the other end of the resistor R5, one end of the resistor R6 and one end of the capacitor C3; the collector of the triode Q2 is connected with one end of a resistor R3; the other end of the resistor R4, the other end of the resistor R6 and the other end of the capacitor C3 are grounded GND; the other end of the resistor R2 and the other end of the resistor R3 are connected with a power supply VCC; the collector of transistor Q2 forms the output of the transistor amplification circuit.
6. A non-contact acoustic wave belt tension measuring device as claimed in claim 1, wherein the low pass filter circuit comprises capacitors C4-C6 and resistors R7-R10;
one end of the capacitor C4 is connected with one end of the resistor R7 to form the input end of the low-pass filter circuit; the other end of the resistor R7 is connected with one end of a resistor R8 and one end of a capacitor C5; the other end of the capacitor C5 is connected with one end of a resistor R9, one end of a resistor R10 and one end of a capacitor C6; the other end of the capacitor C4, the other end of the resistor R8, the other end of the resistor R9 and the other end of the capacitor C6 are grounded to GND; the other end of the resistor R10 forms the output end of the low-pass filter circuit.
7. A non-contact acoustic wave type belt tension measuring device as claimed in claim 1, wherein the operational amplifier circuit includes an operational amplifier U1, capacitors C7-C9, and a resistor R11-a resistor R14;
one end of the capacitor C7 is connected with the No. 2 pin of the operational amplifier U1 to form the input end of the operational amplifier circuit; the other end of the capacitor C7 is connected with the 1 st pin and the 6 th pin of the operational amplifier U1; one end of the resistor R11 is connected with the 3 rd pin of the operational amplifier U1, and the other end of the resistor R11 is grounded; one end of the resistor R12 is connected with the 5 th pin of the operational amplifier U1, and the other end of the resistor R12 is connected with a power supply VCC; one end of the capacitor C8 is connected with a power supply VCC, and the other end of the capacitor C8 is grounded; one end of the capacitor C9, one end of the resistor R13 and one end of the resistor R14 are connected with the 5 th pin of the operational amplifier U1; the other end of the capacitor C9 and the other end of the resistor R13 are grounded GND; the positive power supply end, namely the 4 th pin, of the operational amplifier U1 is connected with a power supply VCC, and the negative power supply end, namely the 11 th pin, of the operational amplifier U1 is connected with the GND; the other end of the resistor R14 is connected with the 7 th pin of the operational amplifier U1 to form the output end of the operational amplifier circuit.
8. A non-contact acoustic wave type belt tension measuring device as claimed in claim 1, wherein the signal shaping circuit comprises, a digital logic chip U2A, and resistors R15-R16;
one end of the resistor R15 forms the input end of the signal shaping circuit; the other end of the resistor R15 is connected with the input end of the digital logic chip U2A, and the output end of the digital logic chip U2A is connected with one end of the resistor R16; and the resistor R16 is arranged at the other end of the output end of the signal shaping circuit.
9. A non-contact acoustic wave type belt tension measuring method implemented by a non-contact acoustic wave type belt tension measuring apparatus according to claim 1, comprising the steps of:
step 1, arranging an acoustic wave sensor (3) near a belt (1) to be measured in a non-contact manner;
2, shifting the belt (1) to be measured to vibrate to send out sound waves, and sensing vibration sound wave signals by the sound wave sensor (3) and sending the signals to the tension measuring instrument (4);
step 3, collecting the vibration sound wave signal by an audio signal collecting circuit of the tension measuring instrument (4), sequentially carrying out primary amplification by a triode amplifying circuit, filtering by a low-pass filtering circuit, secondary amplification by an operational amplifying circuit and shaping by a signal shaping circuit, and then sending the vibration sound wave signal into a single chip microcomputer circuit;
step 4, processing the input vibration sound wave signal by a singlechip circuit of the tension measuring instrument (4) to obtain the natural vibration frequency of the belt (1) to be measured, and calculating the tension of the belt (1) to be measured according to the natural vibration frequency of the belt (1) to be measured;
To＝4×M×W×S2×f2×10-9
in the formula, To is the tension of the belt To be measured, M is the unit mass of the belt To be measured, W is the width of the belt To be measured, S is the tangent length of the belt To be measured, and f is the natural vibration frequency of the belt To be measured.
CN202110068070.0A 2021-01-19 2021-01-19 Non-contact sound wave type belt tension measuring device and method Withdrawn CN112781771A (en)

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Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN117109793A (en) * 2023-10-25 2023-11-24 沈阳机床股份有限公司 Belt tension measuring mechanism and testing method

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN117109793A (en) * 2023-10-25 2023-11-24 沈阳机床股份有限公司 Belt tension measuring mechanism and testing method
CN117109793B (en) * 2023-10-25 2024-01-09 沈阳机床股份有限公司 Belt tension measuring mechanism and testing method

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Application publication date: 20210511