A detector capable of early detecting bearing faults

Abstract

The present invention discloses a detector capable of early detecting bearing faults, which includes a microprocessor. The microprocessor is connected to a power supply and a detection information output device. It further includes a resonance-enhanced piezoelectric sensor. There is an electrically connected sensor trigger detection circuit and a sensor signal selection circuit between the resonance-enhanced piezoelectric sensor and the microprocessor. A sensor signal processing circuit is connected in series to the sensor signal selection circuit. The output end of the sensor signal processing circuit is connected to a programmable gain circuit, and the programmable gain circuit is connected to the microprocessor. The resonance-enhanced piezoelectric sensor can detect impact signals with characteristics such as transience and small amplitude. With the cooperation of relevant circuits, the signal energy is concentrated on the frequency between 30KHz and 40KHz, making the fault signal easy to detect. Finally, the output signal forms a resonance-enhanced signal with a relatively slow attenuation and can form an audio signal and output it for technicians to analyze and obtain the initial fault signal, facilitating timely processing and troubleshooting.

Description

Technical Field

[0001] The present invention relates to the technical field of mechanical equipment fault monitoring, and particularly relates to a detector that can detect bearing faults in advance. Background Art

[0002] Currently, the main sensors used in the field of mechanical equipment fault diagnosis and condition monitoring are still vibration sensors, such as piezoelectric acceleration sensors (also known as accelerometers or acceleration sensors), whose function is to convert mechanical vibration into an electrical signal. When the piezoelectric acceleration sensor senses a vibration signal, a charge proportional to the vibration acceleration will be generated at its output end, which can measure the vibration acceleration, velocity, and displacement, and can also measure some vibration impact signals with larger amplitudes. Due to its small size, light weight, wide frequency band, high reliability, and large dynamic range, it can be widely used in the field of vibration measurement.

[0003] However, for heavy-load and slow-speed rotating equipment, its fault signals are transient and small-amplitude impact signals, which cannot be detected by current vibration sensors and vibration measuring instruments. Conditions such as poor lubrication of bearings cannot be detected by vibration analysis methods either. For the detection of these transient signals, the defects of vibration sensors are obvious, mainly manifested in the following aspects:

[0004] 1. Conventional vibration sensors are resonance attenuation type. That is to say, in order to extract more frequency signals, the original design of the sensor is to absorb the after-vibration. Therefore, vibration analyzers are mainly used to collect periodic signals, and it is difficult to capture transient fault signals with limited impact energy.

[0005] 2. The frequency components of fault signals are very complex and difficult to be limited by the frequency band of vibration analyzers. Moreover, analyzing a too-wide frequency band incurs very high hardware and software costs.

[0006] 3. Early fault signals are often very small and are likely to be submerged by external noise. For example, in the actual operating environment of industrial equipment, the environmental noise is very noisy. If vibration analysis methods are used, it is very difficult to extract transient signals without characteristic frequencies from the environmental noise. Summary of the Invention

[0007] The technical problem to be solved by the present invention is to provide a detector that can detect bearing faults in advance, which can improve the signal strength, reduce environmental noise interference, effectively acquire the transient signals in the initial stage of bearing faults, and generate fault information in a timely manner.

[0008] To solve the above technical problems, the technical solution of the present invention is: a detector capable of early detecting bearing faults, including a microprocessor, the input end of the microprocessor is connected to a power supply, and the output end of the microprocessor is connected to a detection information output device; it also includes a resonance-enhanced piezoelectric sensor, and there is an electrically connected sensor trigger detection circuit between the resonance-enhanced piezoelectric sensor and the microprocessor. The input end of the sensor trigger detection circuit is connected in parallel with a sensor signal selection circuit, the sensor signal selection circuit is connected in series with a sensor signal processing circuit, the output end of the sensor signal processing circuit is connected to a programmable gain circuit, the programmable gain circuit is connected to the microprocessor, and the sensor trigger detection circuit, the sensor signal selection circuit, the sensor signal processing circuit, and the programmable gain circuit are also respectively connected to the power supply.

[0009] As a preferred technical solution, the resonance-enhanced piezoelectric sensor includes a positive conductive rod and a negative conductive rod arranged oppositely, a piezoelectric ceramic sheet is clamped between the positive conductive rod and the negative conductive rod, an electric rod connection fastening sleeve is sleeved on the outer side of one end where the positive conductive rod and the negative conductive rod clamp the piezoelectric ceramic sheet, an electrical insulation device is provided between the electric rod connection fastening sleeve and the positive conductive rod and the piezoelectric ceramic sheet, and the electric rod connection fastening sleeve is connected with the negative conductive rod in a clearance fit manner.

[0010] As a preferred technical solution, the electrical insulation device includes an electrical insulation ring provided between the piezoelectric ceramic sheet and the electric rod connection fastening sleeve, and an electrical insulation sleeve provided between the positive conductive rod and the electric rod connection fastening sleeve. One end of the electrical insulation sleeve abuts against the electrical insulation ring, and the other end of the electrical insulation sleeve extends to the outside of the electric rod connection fastening sleeve.

[0011] As a preferred technical solution, the end faces of the positive conductive rod, the negative conductive rod, and the piezoelectric ceramic sheet are respectively set to be circular, and the end face diameter of the negative conductive rod is larger than the end face diameter of the piezoelectric ceramic sheet. The end face of the part where the negative conductive rod exceeds the piezoelectric ceramic sheet forms an insulating ring positioning platform for the electrical insulation ring.

[0012] As a preferred technical solution, an insulating sleeve limit convex ring is provided at one end of the positive conductive rod in contact with the piezoelectric ceramic sheet, and an insulating sleeve limit concave ring cooperating with the insulating sleeve limit platform is provided on the electrical insulation sleeve.

[0013] As a preferred technical solution, the sensor trigger detection circuit includes a low-pass filtering resistor R31 electrically connected to the output end of the resonance-enhanced piezoelectric sensor. The output end of the low-pass filtering resistor R31 is grounded through a low-pass filtering capacitor C34. The output end of the low-pass filtering resistor R31 is also connected to the non-inverting input end of an operational amplifier A1. The inverting input end of the operational amplifier A1 is connected to its output end. The output end of the operational amplifier A1 is connected to the microprocessor. The power supply end of the operational amplifier A1 is connected to the power supply through a voltage-dividing resistor R59, and the voltage-dividing resistor R59 is also safely grounded through a capacitor C52.

[0014] As a preferred technical solution, the sensor signal selection circuit includes a series selection circuit and a parallel selection circuit connected in series at the input end of the low-pass filtering resistor. The output end of the series selection circuit is also connected to the sensor signal processing circuit;

[0015] The series selection circuit includes a polar capacitor C33 connected to the input end of the low-pass filtering resistor R31. The output end of the polar capacitor C33 is successively connected in series with a capacitor C45 and an inductor L3. The output end of the inductor L3 is connected to the sensor signal processing circuit; the parallel selection circuit includes an inductor L4 and a capacitor 16 connected in parallel at the output end of the inductor L3. The output ends of the capacitor 16 and the inductor L4 are commonly grounded.

[0016] As a preferred technical solution, the sensor signal processing circuit is set as a band-pass filtering circuit, including a resistor R50 and a capacitor C48 connected in series. The input end of the resistor R50 is connected to the output end of the inductor L3. The input end of the capacitor C48 is connected with a capacitor C47. The output end of the capacitor C48 is connected with a resistor R51. The output end of the capacitor C48, the output end of the capacitor C47, and the output end of the resistor R51 are respectively connected to the programmable gain circuit.

[0017] As a preferred technical solution, the programmable gain circuit includes a programmable amplifier U1. The external reference end of the programmable amplifier U1 is connected to the reference voltage circuit. The analog input end of the programmable amplifier U1 is connected to the band-pass filtering circuit. The analog output end of the programmable amplifier U1 is connected to the microprocessor.

[0018] As an improvement to the above technical solution, the detection information output device includes an audio conversion circuit provided in the microprocessor. The output end of the audio conversion circuit is connected with an audio player, and also includes an LED display connected to the output end of the microprocessor.

[0019] Due to the adoption of the above technical solution, a detector capable of early detecting bearing faults includes a microprocessor. The input end of the microprocessor is connected to a power supply, and the output end of the microprocessor is connected to a detection information output device. It also includes a resonance-enhanced piezoelectric sensor. There is a sensor trigger detection circuit electrically connected between the resonance-enhanced piezoelectric sensor and the microprocessor. The input end of the sensor trigger detection circuit is connected in parallel with a sensor signal selection circuit. The sensor signal selection circuit is connected in series with a sensor signal processing circuit. The output end of the sensor signal processing circuit is connected to a programmable gain circuit, and the programmable gain circuit is connected to the microprocessor. The sensor trigger detection circuit, the sensor signal selection circuit, the sensor signal processing circuit, and the programmable gain circuit are also respectively connected to the power supply. The beneficial effects of the present invention are as follows: The resonance-enhanced piezoelectric sensor can detect the fault signals of heavy-load and slow-rotating equipment. The above-mentioned fault signals generally have characteristics such as transience and small amplitude. With the cooperation of relevant circuits, finally, the energy of the detected impact signal can be concentrated on the frequency between 30KHz and 40KHz, improving the signal intensity and minimizing the interference of environmental noise as much as possible, making the fault signals easy to detect. In addition, after the cooperation of each circuit, the output signal can form a resonance-enhanced signal with a relatively slow attenuation (which can last for more than 20 cycles). Under the action of the microprocessor, an audio signal can be formed and output through the detection information output device for fault diagnosis engineers to analyze, so as to obtain the initial fault signals of the measured equipment and facilitate timely handling and troubleshooting of faults. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] The following drawings are only intended to illustrate and explain the present invention schematically and do not limit the scope of the present invention. Among them:

[0021] Figure 1 is the structural block diagram of an embodiment of the present invention;

[0022] Figure 2 is the structural schematic diagram of an embodiment of the present invention;

[0023] Figure 3 is Figure 1 the enlarged structural schematic diagram at A in

[0024] Figure 4 is the circuit schematic diagram of the sensor trigger detection circuit, the sensor signal selection circuit, the sensor signal processing circuit, and the programmable gain circuit in an embodiment of the present invention;

[0025] Figure 5 is the detection signal diagram of the resonance-enhanced piezoelectric sensor in an embodiment of the present invention;

[0026] Figure 6It is the envelope signal diagram corresponding to the detection signal of the resonance-enhanced piezoelectric sensor generated by the embodiment of the present invention;

[0027] Figure 7 It is the audio signal diagram corresponding to the detection signal of the resonance-enhanced piezoelectric sensor of the embodiment of the present invention;

[0028] In the figure: 1 - positive conductive rod; 2 - negative conductive rod; 3 - piezoelectric ceramic sheet; 4 - electric rod connection fastening sleeve; 5 - electrical insulation ring; 6 - electrical insulation sleeve; 7 - clamping pre-tightening inclined plane. Specific embodiments

[0029] The present invention will be further described below in conjunction with the accompanying drawings and embodiments. In the following detailed description, only some exemplary embodiments of the present invention are described by way of illustration. It is understood that those of ordinary skill in the art can recognize that the described embodiments can be modified in various different ways without departing from the spirit and scope of the present invention. Therefore, the drawings and description are illustrative in nature and not intended to limit the scope of protection of the claims.

[0030] As Figure 1 shown, a detector capable of early detecting bearing faults includes a microprocessor. The input end of the microprocessor is connected to a power supply, and the output end of the microprocessor is connected to a detection information output device. The power supply can provide working voltage for electronic components in the entire detector. The detection information output device includes an audio conversion circuit disposed in the microprocessor. The output end of the audio conversion circuit is connected to an audio player, and further includes an LED display connected to the output end of the microprocessor. The audio player can be set as a headset and worn by a fault diagnosis engineer. The microprocessor is an ARM microprocessor and can convert the fault signal into an audio signal and play it through the headset.

[0031] This embodiment further includes a resonance-enhanced piezoelectric sensor. There is a sensor trigger detection circuit electrically connected between the resonance-enhanced piezoelectric sensor and the microprocessor. A sensor signal selection circuit is connected in parallel to the input end of the sensor trigger detection circuit. The sensor signal selection circuit is connected in series with a sensor signal processing circuit. The output end of the sensor signal processing circuit is connected to a programmable gain circuit, and the programmable gain circuit is connected to the microprocessor. The sensor trigger detection circuit, the sensor signal selection circuit, the sensor signal processing circuit, and the programmable gain circuit are also respectively connected to the power supply. The resonance-enhanced piezoelectric sensor is responsible for picking up fault signals. The sensor trigger detection circuit is used to detect whether it is normally connected to the microprocessor. The sensor signal selection circuit, the sensor signal processing circuit, and the programmable gain circuit are used to select and process the frequencies of the detection signals of the resonance-enhanced piezoelectric sensor for further analysis by the microprocessor.

[0032] As Figure 2 and Figure 3 shown, the resonance-enhanced piezoelectric sensor includes a positive electrode conductive rod 1 and a negative electrode conductive rod 2 arranged oppositely. A piezoelectric ceramic sheet 3 is clamped between the positive electrode conductive rod 1 and the negative electrode conductive rod 2. An electric rod connection fastening sleeve 4 is sleeved outside one end of the positive electrode conductive rod 1 and the negative electrode conductive rod 2 that clamps the piezoelectric ceramic sheet 3. An electrical insulation device is provided between the electric rod connection fastening sleeve 4, the positive electrode conductive rod 1, and the piezoelectric ceramic sheet 3. The electric rod connection fastening sleeve 4 is connected with the negative electrode conductive rod 2 in a clearance fit.

[0033] In this embodiment, the main body part of the positive electrode conductive rod 1 is a cylindrical structure with a diameter of 7 mm and a length of 35 mm. The negative electrode conductive rod 2 is a cylindrical structure with a diameter of 7 mm and a length of 40 mm. The materials of the positive electrode conductive rod 1, the negative electrode conductive rod 2, and the electric rod connection fastening sleeve 4 are all 304 stainless steel, which has good high-temperature resistance and corrosion resistance and low requirements for the use environment. The preferred size of the piezoelectric ceramic sheet 3 is a circular sheet structure with a diameter of 7 mm and a thickness of 1 mm, and the material is lead zirconate titanate. The electric rod connection fastening sleeve 4 is used to assemble and fix the various components of the sensor together.

[0034] Specifically, the electrical insulation device includes an electrical insulation ring 5 disposed between the piezoelectric ceramic sheet 3 and the electrical rod connection fastening sleeve 4, and an electrical insulation sleeve 6 disposed between the positive electrode conductive rod 1 and the electrical rod connection fastening sleeve 4. One end of the electrical insulation sleeve 6 abuts against the electrical insulation ring 5, and the other end of the electrical insulation sleeve 6 extends to the outside of the electrical rod connection fastening sleeve 4. The electrical insulation ring 5 is set as a ceramic insulation ring, and the electrical insulation sleeve 6 is set as a plastic sleeve. It can be seen from the above structure that the electrical insulation sleeve 6 and the electrical insulation ring 5 can separate the positive electrode conductive rod 1 and the negative electrode conductive rod 2 to prevent internal short - circuit of the sensor. The electrical rod connection fastening sleeve 4 is in direct contact with the negative electrode conductive rod 2, so the two are electrically conductive. At the same time, the negative electrode conductive rod 2 is electrically conductive with one end face of the piezoelectric ceramic sheet 3.

[0035] During the actual working process of the sensor, a resonance system is ingeniously constructed inside the electrical rod connection fastening sleeve 4. The oscillator of this resonance system is the piezoelectric ceramic sheet 3, and the restoring force of this system comes from the pre - tightening force of the electrical rod connection fastening sleeve 4 on the positive electrode conductive rod 1, the negative electrode conductive rod 2, and the piezoelectric ceramic sheet 3. Under an appropriate pre - tightening force, when the piezoelectric ceramic sheet 3 generates a small displacement Δx, the restoring force F is approximately equal to - kΔx. Assuming the mass of the piezoelectric ceramic sheet 3 is m, then the resonance frequency is:

[0036]

[0037] The piezoelectric ceramic sheet 3 of this embodiment serves as a mass block. It has a light mass, which is beneficial to the formation of resonance in the sensor structure and becomes the basis for picking up transient weak impact signals, thereby realizing the picking up of fault signals and resonance enhancement.

[0038] In this embodiment, the end faces of the positive electrode conductive rod 1, the negative electrode conductive rod 2, and the piezoelectric ceramic sheet 3 are respectively circular, and the end - face diameter of the negative electrode conductive rod 2 is larger than the end - face diameter of the piezoelectric ceramic sheet 3. The end - face of the part of the negative electrode conductive rod 2 that exceeds the piezoelectric ceramic sheet 3 forms an insulation ring positioning platform for the electrical insulation ring 5, so that a clearance fit is formed between the electrical insulation ring 5, the piezoelectric ceramic sheet 3, and the electrical rod connection fastening sleeve 4. One end of the positive electrode conductive rod 1 in contact with the piezoelectric ceramic sheet 3 is provided with an insulation sleeve limit convex ring, and the electrical insulation sleeve 6 is provided with an insulation sleeve limit concave ring that cooperates with the insulation sleeve limit platform, so that an interference fit is formed between the positive electrode conductive rod 1 and the electrical insulation sleeve 6. One end of the negative electrode conductive rod 2 in contact with the piezoelectric ceramic sheet 3 is provided with a fastening sleeve limit ring platform, and the electrical rod connection fastening sleeve 4 is provided with a fastening sleeve limit ring groove that cooperates with the fastening sleeve limit ring platform. The electrical insulation ring 5 and part of the electrical insulation sleeve 6 are respectively assembled in the fastening sleeve limit ring groove, so that a clearance fit is formed between the electrical rod connection fastening sleeve 4 and the negative electrode conductive rod 2.

[0039] During assembly, after applying a certain pre-tightening force among the positive electrode conductive rod 1, the piezoelectric ceramic sheet 3 and the negative electrode conductive rod 2, then press the end of the electrical insulation ring 5 to keep the pre-tightening force among the positive electrode conductive rod 1, the piezoelectric ceramic sheet 3 and the negative electrode conductive rod 2 unchanged. On the premise that the mass m of the piezoelectric ceramic sheet 3 remains unchanged, by adjusting the pre-tightening force to change the k value, the resonance frequency f can be made about 31 KHz.

[0040] In this embodiment, a clamping pre-tightening inclined surface 7 is provided on the outer peripheral surface of one end of the electric rod connection fastening sleeve 4 sleeving the positive electrode conductive rod 1. After pressing the end of the electrical insulation ring 5, in order to keep the pre-tightening force among the positive electrode conductive rod 1, the piezoelectric ceramic sheet 3 and the negative electrode conductive rod 2 unchanged, a clamping tool can be used to clamp the clamping pre-tightening inclined surface 7 and squeeze it inward, so that the inner surface of the clamping pre-tightening inclined surface 7 clamps the outer periphery of the electrical insulation sleeve 6 to achieve the effect of maintaining the pre-tightening force.

[0041] As Figure 4 shown, the sensor trigger detection circuit includes a low-pass filter resistor R31 electrically connected to the output end of the resonance-enhanced piezoelectric sensor. The output end of the low-pass filter resistor R31 is grounded through a low-pass filter capacitor C34. The output end of the low-pass filter resistor R31 is also connected to the non-inverting input end of an operational amplifier A1. The inverting input end of the operational amplifier A1 is connected to its output end. The output end of the operational amplifier A1 is connected to the microprocessor. The power supply end of the operational amplifier A1 is connected to the power supply through a voltage-dividing resistor R59, and the voltage-dividing resistor R59 is also safely grounded through a capacitor C52.

[0042] The model of the operational amplifier A1 can be selected as TLC2272ACD. The low-pass filter resistor R31 and the low-pass filter capacitor C34 form a low-pass filter, and then the operational amplifier A1 is used for signal following to overcome the problems of small charge signal at the output end of the resonance-enhanced piezoelectric sensor and weak driving ability. After the operational amplifier A1 forms signal following, it enters the chip STM32F429 in the microprocessor for analog / digital conversion and use to achieve the purpose of whether the resonance-enhanced piezoelectric sensor is normally connected.

[0043] The sensor signal selection circuit includes a series frequency selection circuit and a parallel frequency selection circuit connected in series in turn at the input end of the low-pass filtering resistor, and the output end of the series frequency selection circuit is also connected to the sensor signal processing circuit. Specifically, the series frequency selection circuit includes a polarized capacitor C33 connected to the input end of the low-pass filtering resistor R31. The output end of the polarized capacitor C33 is successively connected in series with a capacitor C45 and an inductor L3, and the output end of the inductor L3 is connected to the sensor signal processing circuit; the parallel frequency selection circuit includes an inductor L4 and a capacitor 16 connected in parallel at the output end of the inductor L3, and the output ends of the capacitor 16 and the inductor L4 are commonly grounded.

[0044] Among them, the capacitor C45 and the inductor L3 form a series LC frequency selection circuit. When the signal frequency reaches the resonance frequency, the impedance of the series frequency selection circuit to the signal approaches zero, while the inductor L4 and the capacitor C16 form a parallel LC frequency selection circuit. When the signal frequency reaches the resonance frequency, its equivalent impedance approaches infinity. For example, assuming that the frequency of the output signal of the resonance-enhanced piezoelectric sensor is 32KHz, by selecting appropriate capacitance and inductance values so that the resonance frequency of the LC circuit is 32KHz, then these two LC circuits will form a frequency selection circuit with a very high quality factor (high Q value). The selection of capacitance and inductance values refers to the following formula:

[0045]

[0046] In this embodiment, the sensor signal processing circuit is set as a band-pass filtering circuit, including a resistor R50 and a capacitor C48 connected in series. The input end of the resistor R50 is connected to the output end of the inductor L3. The input end of the capacitor C48 is connected with a capacitor C47, and the output end of the capacitor C48 is connected with a resistor R51. The output end of the capacitor C48, the output end of the capacitor C47, and the output end of the resistor R51 are respectively connected to the programmable gain circuit. The resistor R50, the capacitor C47, the capacitor C48, and the resistor R51 further select the frequency of the signal and send the signal to the programmable gain circuit. The amplitude change range of the sound signal detected by the resonance-enhanced piezoelectric sensor is relatively large, and the programmable gain circuit is adopted to cover a wider range.

[0047] The programmable gain circuit includes a programmable amplifier U1. The external reference terminal of the programmable amplifier U1 is connected to a reference voltage circuit. The analog input terminal of the programmable amplifier U1 is connected to the band-pass filter circuit. The analog output terminal of the programmable amplifier U1 is connected to the microprocessor. The programmable amplifier U1 can use the chip MCP6S21. In order to make the output signal Vout of the chip MCP6S21 within the acquisition range of the chip STM32F429, it is necessary to raise its reference voltage to 1.65V. In this embodiment, a reference voltage circuit is specifically designed.

[0048] The reference voltage circuit includes an operational amplifier A2. The positive input terminal of the operational amplifier A2 is connected to the power supply voltage through a voltage-dividing resistor R47. A grounding capacitor C35, a grounding capacitor C32, and a grounding capacitor C37 are sequentially connected in parallel between the voltage-dividing resistor R47 and the power supply voltage terminal, and the grounding capacitor C35, the grounding capacitor C32, and the grounding capacitor C37 are commonly grounded. A voltage-dividing resistor R48 and a grounding capacitor C39 are sequentially connected in parallel between the voltage-dividing resistor R47 and the positive input terminal of the operational amplifier A2, and the voltage-dividing resistor R48 and the grounding capacitor C39 are commonly grounded. The negative input terminal of the operational amplifier A2 is connected to the external reference terminal of the operational amplifier A2. The output terminal of the operational amplifier A2 is also connected to the external reference terminal of the operational amplifier A2 through a resistor R49, and a grounding capacitor C22 and a grounding capacitor C23 are further provided between the resistor R49 and the external reference terminal of the operational amplifier A2, and the grounding capacitor C22 and the grounding capacitor C23 are commonly grounded. The operational amplifier A2 is set as the chip LMC6482IM / NS / SOP8. The reference voltage circuit uses the voltage-dividing resistors R47 and R48 for voltage division, and then uses the operational amplifier A2 to achieve voltage following to improve the driving ability. The voltage value of the VCC terminal of the chip MCP6S21 is 3.3V, and the voltage value of the VRE terminal is 1.65V.

[0049] For example, the signal at the Vout of the operational amplifier A2 is an amplitude-modulated 32KHz signal (as Figure 5 shown). The ARM microprocessor's built-in ADC (with a maximum sampling rate of 2.4Msps) is used to collect data from this signal. Then, the floating-point processor FPU (equivalent to a DSP) inside the ARM microprocessor quickly samples, demodulates, and envelopes the signal to obtain an envelope signal (as Figure 6As shown, the formed envelope signal can be directly displayed on the LED display and can be seen by the users of the bearing detector. In this process, the actual process of obtaining the envelope is the demodulation process, which is well-known to those skilled in the art and will not be described in detail here. The ARM microprocessor further modulates the envelope signal into an audio signal (with a frequency of several hundred hertz) that can be heard by the human ear (as shown in Figure 7 ), so that the fault diagnosis engineer can hear it from the earphone, realizing the detection and utilization of the impact pulse signal generated by the initial or early-stage faults of the bearing. The envelope signal can also be stored by the ARM microprocessor. After the measurement is completed, the signals in the processing process can be statistically analyzed to facilitate the analysis of the bearing status or faults using techniques such as dBm / dBc (peak / root mean square value), HR / LR (high frequency / low frequency), etc.

[0050] In most bearing faults, poor lubrication, bearing faults, and temperature rise always occur together. Therefore, a pyroelectric module can be extendedly set in the bearing detector to detect the temperature of the bearing cover.

[0051] In traditional technologies, the quality of vibration meters is mainly reflected by their broadband capabilities. That is to say, many frequency signals need to pass through the conditioning circuit. Vibration meters mainly detect frequency information, which is a continuous signal with limited power and infinite energy. However, the detector in this embodiment can detect transient signals with limited energy. Therefore, through it, the impact pulse signal formed by the collision of the roughness texture between the balls and the raceway due to poor lubrication in the early stage of bearing faults can be detected. Therefore, this embodiment has become the only device that can detect the bearing oil film thickness at present and can detect and predict the occurrence of faults 3 to 6 months in advance.

[0052] In summary, this embodiment has the following advantages:

[0053] 1. Enrich the signal in the frequency band of 30KHz - 40KHz by the method of resonance enhancement, so that the signal intensity is increased by more than 6 - 7 times compared with before enrichment. In this way, faults can be detected 3 to 6 months earlier than the vibration analysis method, and the transient signals in the early stage of bearing faults can be accurately collected.

[0054] 2. Since the frequency of the signal is concentrated in a narrow band, it is relatively easy to achieve stable gain amplification of the signal.

[0055] 3. Since the fault signal after resonance enhancement is an energy signal, mainly looking at the energy value and no longer carrying frequency information, a lower sampling rate can be used to achieve signal acquisition after detection and demodulation to obtain a lower-frequency signal.

[0056] 4. The lubrication condition of the bearing can be analyzed by using the comparison methods of dBm / dBc (peak value / carpet value) and HR / LR (high frequency / low frequency) of the resonance-enhanced piezoelectric sensor.

[0057] The above shows and describes the basic principle, main features and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited by the above embodiments, and what is described in the above embodiments and the specification only illustrates the principle of the present invention. Without departing from the spirit and scope of the present invention, the present invention will have various changes and improvements, and these changes and improvements all fall within the scope of the present invention claimed. The scope of the present invention claimed is defined by the appended claims and their equivalents.

Claims

1. A detector capable of early detecting bearing faults, comprising a microprocessor, characterized in that: The input end of the microprocessor is connected to a power supply, and the output end of the microprocessor is connected to a detection information output device; it further includes a resonance-enhanced piezoelectric sensor. There is an electrically connected sensor trigger detection circuit between the resonance-enhanced piezoelectric sensor and the microprocessor. The input end of the sensor trigger detection circuit is connected in parallel with a sensor signal selection circuit. The sensor signal selection circuit is connected in series with a sensor signal processing circuit. The output end of the sensor signal processing circuit is connected to a programmable gain circuit. The programmable gain circuit is connected to the microprocessor. The sensor trigger detection circuit, the sensor signal selection circuit, the sensor signal processing circuit, and the programmable gain circuit are also respectively connected to the power supply. The resonance-enhanced piezoelectric sensor is responsible for picking up fault signals. The sensor trigger detection circuit is used to detect whether it is normally connected to the microprocessor. The sensor signal selection circuit, the sensor signal processing circuit, and the programmable gain circuit realize the selection and processing of the detection signal usage frequency of the resonance-enhanced piezoelectric sensor for the analysis and use of the microprocessor; The resonance-enhanced piezoelectric sensor includes a positive conductive rod and a negative conductive rod arranged oppositely. A piezoelectric ceramic sheet is clamped between the positive conductive rod and the negative conductive rod. An electric rod connection fastening sleeve is sleeved outside one end of the positive conductive rod and the negative conductive rod where the piezoelectric ceramic sheet is clamped. An electrical insulation device is provided between the electric rod connection fastening sleeve, the positive conductive rod, and the piezoelectric ceramic sheet. The electric rod connection fastening sleeve is connected to the negative conductive rod with a clearance fit.

2. The detector for early detection of bearing faults according to claim 1, characterized in that: The electrical insulation device includes an electrical insulation ring provided between the piezoelectric ceramic sheet and the electric rod connection fastening sleeve, and an electrical insulation sleeve provided between the positive conductive rod and the electric rod connection fastening sleeve. One end of the electrical insulation sleeve abuts against the electrical insulation ring, and the other end of the electrical insulation sleeve extends outside the electric rod connection fastening sleeve.

3. The detector for early detection of bearing faults according to claim 2, wherein: The end faces of the positive conductive rod, the negative conductive rod, and the piezoelectric ceramic sheet are respectively set to be circular, and the end face diameter of the negative conductive rod is larger than the end face diameter of the piezoelectric ceramic sheet. The part of the end face of the negative conductive rod that exceeds the piezoelectric ceramic sheet forms an insulation ring positioning platform for the electrical insulation ring.

4. The detector for early detection of bearing faults according to claim 2, characterized in that: One end of the positive conductive rod in contact with the piezoelectric ceramic sheet is provided with an insulating sleeve limiting convex ring, and the electrical insulation sleeve is provided with an insulating sleeve limiting concave ring that cooperates with the insulating sleeve limiting platform.

5. The detector for early detection of bearing faults according to claim 1, wherein: The sensor trigger detection circuit includes a low-pass filter resistor R31 electrically connected to the output end of the resonance-enhanced piezoelectric sensor. The output end of the low-pass filter resistor R31 is grounded through a low-pass filter capacitor C34. The output end of the low-pass filter resistor R31 is also connected to the non-inverting input end of an operational amplifier A1. The inverting input end of the operational amplifier A1 is connected to its output end. The output end of the operational amplifier A1 is connected to the microprocessor. The power supply end of the operational amplifier A1 is connected to the power supply through a voltage-dividing resistor R59. The voltage-dividing resistor R59 is also safely grounded through a capacitor C52.

6. The detector for early detection of bearing faults according to claim 5, characterized in that: The sensor signal selection circuit includes a series selection circuit and a parallel selection circuit connected in series at the input end of the low-pass filter resistor R31 in sequence. The output end of the series selection circuit is also connected to the sensor signal processing circuit; The series selection circuit includes a polar capacitor C33 connected to the input end of the low-pass filter resistor R31. The output end of the polar capacitor C33 is sequentially connected in series with a capacitor C45 and an inductor L3. The output end of the inductor L3 is connected to the sensor signal processing circuit; the parallel selection circuit includes an inductor L4 and a capacitor 16 connected in parallel at the output end of the inductor L3. The output ends of the capacitor 16 and the inductor L4 are commonly grounded.

7. The detector for early detection of bearing faults according to claim 6, wherein: The sensor signal processing circuit is set as a band-pass filter circuit, including a resistor R50 and a capacitor C48 connected in series. The input end of the resistor R50 is connected to the output end of the inductor L3. The input end of the capacitor C48 is connected with a capacitor C47. The output end of the capacitor C48 is connected with a resistor R51. The output end of the capacitor C48, the output end of the capacitor C47, and the output end of the resistor R51 are respectively connected to the programmable gain circuit.

8. The detector for early detection of bearing faults according to claim 7, wherein: The programmable gain circuit includes a programmable amplifier U1. The external reference end of the programmable amplifier U1 is connected to the reference voltage circuit. The analog input end of the programmable amplifier U1 is connected to the band-pass filter circuit. The analog output end of the programmable amplifier U1 is connected to the microprocessor.

9. A detector for early detection of bearing faults according to any one of claims 1 to 8, characterized in that: The detection information output device includes an audio conversion circuit provided in the microprocessor. The output end of the audio conversion circuit is connected with an audio player, and also includes an LED display connected to the output end of the microprocessor.

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