A sound box and an abnormal sound testing platform thereof

Abstract

The utility model discloses a kind of sound box and its abnormal sound test bench, including shell, magnetic attraction type vibration sensor and earphone, signal processing board is arranged in shell, shell one end has front operation panel, sensor signal input interface, audio signal output interface, single / dual channel switch switch, external trigger IO terminal and gain resistance adjusting knob are set on front operation panel, sensor signal input interface, audio signal output interface, single / dual channel switch switch, external trigger IO terminal and gain resistance adjusting knob are all with signal processing board electric connection, magnetic attraction type vibration sensor is electrically connected with signal processing board by sensor signal input interface, earphone is plugged into audio signal output interface, abnormal sound test bench includes test bench, test bench is placed with sound box, measuring piece fixed tooling, load motor and starting switch, test bench bottom is placed with electrical control cabinet, and dynamic abnormal sound signal under different working conditions can be flexibly captured.

Description

Technical Field

[0001] This utility model belongs to the field of testing technology, specifically relating to a listening box and its abnormal noise testing platform. Background Technology

[0002] Driven by both global "dual carbon" goals and the rapid iteration of the new energy vehicle industry, the development of new energy vehicles is accelerating at an unprecedented pace. To seize market opportunities and respond to policy guidance and consumer demand, OEMs are generally compressing product development cycles. However, this "acceleration" process also poses a severe challenge to the R&D and production quality control systems of sub-component systems (including powertrain systems, interior systems, and exterior systems). The traditional fault diagnosis model based on bench durability testing and multi-dimensional data collection and analysis is no longer suitable for the current "short cycle, high capacity" production rhythm due to its complex process and long time consumption (a single complete test often takes several hours to several days). It also cannot meet the aftermarket's immediate demand for rapid troubleshooting of abnormal noises and faults in various levels of components.

[0003] Taking the powertrain system as an example: Engine noise, as one of the core indicators reflecting its mechanical health, is often directly related to potential faults such as piston knocking, valve noise, and bearing wear. If the problematic parts cannot be identified and eliminated in time, it will not only lead to the deterioration of the vehicle's NVH (noise, vibration, and harshness) performance and affect the user's driving experience, but may also cause subsequent powertrain reliability risks, increase after-sales maintenance costs, and damage the brand's reputation.

[0004] However, existing abnormal noise detection technologies have obvious limitations: fixed vibration monitoring equipment on the production line can only cover preset measurement points and is difficult to flexibly capture dynamic abnormal noise signals under different working conditions. Utility Model Content

[0005] In view of this, the present invention provides a listening box and a noise testing platform thereof.

[0006] The specific plan is as follows: A listening box includes a housing, a magnetic vibration sensor, and earphones. A signal processing board is disposed inside the housing, and a front operation panel is disposed at one end of the housing. The front operation panel is provided with a sensor signal input interface, an audio signal output interface, a single / dual channel switch, an external trigger I / O terminal, and a gain resistor adjustment knob. The sensor signal input interface, the audio signal output interface, the single / dual channel switch, the external trigger I / O terminal, and the gain resistor adjustment knob are all electrically connected to the signal processing board. The magnetic vibration sensor is electrically connected to the signal processing board through the sensor signal input interface, and the earphones are plugged into and detached from the audio signal output interface.

[0007] The listening box also includes a Bluetooth audio transmission module, the earphones are wirelessly connected to the Bluetooth audio transmission module, and the Bluetooth audio transmission module is plugged into and detached from the audio signal output interface.

[0008] The signal processing board is equipped with a constant current source, a high-pass filter, a first-stage amplifier circuit, a band-pass filter, a second-stage amplifier circuit, a Class D power amplifier circuit, and a power amplifier protection circuit. The constant current source is electrically connected to the first-stage amplifier circuit through the high-pass filter. The first-stage amplifier circuit is electrically connected to the second-stage amplifier circuit through the band-pass filter. The second-stage amplifier circuit is electrically connected to the power amplifier protection circuit through the Class D power amplifier circuit.

[0009] The magnetic vibration sensor is electrically connected to a constant current source through a sensor signal input interface. The gain resistor adjustment knob is electrically connected to a Class D power amplifier circuit. The external trigger I / O terminal is electrically connected to the input terminal of the power amplifier protection circuit. The signal processing board is also provided with a single / dual channel switching circuit. The single / dual channel switching switch is electrically connected to the power amplifier protection circuit through the single / dual channel switching circuit. The output terminal of the power amplifier protection circuit is electrically connected to the audio signal output interface.

[0010] The magnetic vibration sensor is of two types, and the two magnetic vibration sensors are piezoelectric accelerometers. The sensor signal input interface is two-way, and the two piezoelectric accelerometers are plugged and plugged into the two sensor signal input interfaces respectively. The two sensor signal input interfaces are BNC interface terminals.

[0011] The magnetic vibration sensor also includes a sleeve. The bottom of the sleeve has a receiving cavity and a partition. A magnet is placed inside the receiving cavity. The top of the receiving cavity is fixedly connected to the partition. A piezoelectric accelerometer is placed on the partition and on the side opposite to the receiving cavity. The partition has a through hole. A mounting screw is provided on the magnet. The bottom of the piezoelectric accelerometer has a threaded hole. The mounting screw fixes the magnet and the piezoelectric accelerometer to the two sides of the partition respectively through the through hole. The side wall of the sleeve also has a sensor placement hole and an anti-attenuation hole. The sleeve is an aluminum alloy sleeve.

[0012] The audio signal output interface is an AUX standard audio interface.

[0013] The housing contains a battery and a battery management circuit. The battery is electrically connected to a signal processing board through the battery management circuit. The other end of the housing is also provided with a rear operation panel, which is equipped with a charging interface, a power switch, and a power display screen. The power switch, power display screen, and charging interface are electrically connected to the battery management circuit.

[0014] A noise testing bench including a listening box comprises a test frame, on which a listening box, a test piece fixing fixture, a load motor, and a start switch are placed. An electrical control cabinet is placed at the bottom of the test frame. The start switch is electrically connected to the electrical control cabinet, and the electrical control cabinet is electrically connected to an external trigger I / O terminal on the listening box. The electrical control cabinet is also electrically connected to the load motor, which applies a load to the test piece. The test piece fixing fixture clamps the test piece, and the test piece is electrically connected to a sensor signal input interface on the listening box via a magnetic vibration sensor.

[0015] The present invention discloses a listening box and its abnormal noise testing platform, which adopts a dual-channel portable abnormal noise detection device with magnetic vibration sensor and sound-to-electric conversion technology. It integrates a high-sensitivity magnetic vibration sensor, a vibration-to-sound conversion circuit and noise-canceling headphones to realize the integrated function of "vibration signal acquisition - real-time sound-to-electric conversion - human ear audible output".

[0016] In application scenarios, inspectors can flexibly fix the sensor to the main body of the component, such as the engine block, cylinder head and other key parts, or the electric guide rail of the seat, by magnetic attraction. The vibration characteristics of each position can be quickly captured without disassembling the component, and the converted sound signal can be listened to in real time through headphones. Combined with the movement positioning of the magnetic vibration sensor, the location of the abnormal noise source can be located within minutes, thereby quickly determining whether the component system is in normal working condition.

[0017] In addition, this utility model also includes an abnormal noise test bench. The abnormal noise test bench can not only be adapted to the batch rapid screening of the production line, but also shorten the single-unit testing time to 1 / 10 of the traditional method. It can also meet the real-time fault diagnosis needs in the complex environment of the after-sales market, and provide efficient and convenient technical support for the R&D quality control and full life cycle operation and maintenance of new energy vehicle related component systems. Attached Figure Description

[0018] Figure 1 This is a schematic diagram of the front control panel of the audio box.

[0019] Figure 2 This is a schematic diagram of the control logic of the audio box circuit.

[0020] Figure 3 This is a schematic diagram of an accelerometer.

[0021] Figure 4 This is a schematic diagram of a piezoelectric accelerometer.

[0022] Figure 5 This is a schematic diagram of the sleeve structure.

[0023] Figure 6 It is the first-order torsional mode diagram of the sleeve.

[0024] Figure 7 This is a diagram of the control panel on the back of the speaker box.

[0025] Figure 8 This is a schematic diagram of a test bench for abnormal noise from listening boxes.

[0026] Figure 9 This is a schematic diagram of the fixture for fixing the measuring piece. Detailed Implementation

[0027] The technical solutions in the embodiments of this utility model will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the implementation of this utility model, not all of it. All other embodiments obtained by those skilled in the art based on the embodiments of this utility model without creative effort are within the scope of protection of this utility model.

[0028] like Figure 1 As shown, a listening box includes a housing 1, a magnetic vibration sensor 8, and earphones. A signal processing board is disposed inside the housing 1, and a front operation panel 2 is disposed at one end of the housing 1. The front operation panel 2 is provided with a sensor signal input interface 4, an audio signal output interface 6, a single / dual channel switch 3, an external trigger I / O terminal 5, and a gain resistor adjustment knob 7. The sensor signal input interface 4, the audio signal output interface 6, the single / dual channel switch 3, the external trigger I / O terminal 5, and the gain resistor adjustment knob 7 are all electrically connected to the signal processing board. The magnetic vibration sensor 8 is electrically connected to the signal processing board through the sensor signal input interface 4, and the earphones are plugged into and detached from the audio signal output interface 6.

[0029] The listening box also includes a Bluetooth audio transmission module. The earphones are wirelessly connected to the Bluetooth audio transmission module, which is plugged into the audio signal output interface 6. The gain resistor adjustment knob 7 is a damping knob that can adjust the playback volume.

[0030] like Figure 2 As shown, the signal processing board is equipped with a constant current source, a high-pass filter, a first-stage amplifier circuit, a band-pass filter, a second-stage amplifier circuit, a Class D power amplifier circuit, and a power amplifier protection circuit. The constant current source is electrically connected to the first-stage amplifier circuit through the high-pass filter. The first-stage amplifier circuit is electrically connected to the second-stage amplifier circuit through the band-pass filter. The second-stage amplifier circuit is electrically connected to the power amplifier protection circuit through the Class D power amplifier circuit.

[0031] The constant current source is a dual-channel IEPE constant current source with a current output of 4mA. The first-stage amplifier circuit is the basic circuit that amplifies a weak signal into a stronger signal, implemented using transistors or operational amplifiers. The second-stage amplifier circuit consists of two cascaded operational amplifiers or transistors, providing high gain and high output swing. The Class D power amplifier circuit uses pulse width modulation (PWM) technology to convert the input analog signal into a series of pulse signals. The Class D power amplifier circuit uses MOSFET switching elements and operates in switching mode, achieving an efficiency of up to 90%-95%, far exceeding that of traditional Class A and Class AB amplifiers. Because the switching elements consume almost no power in both on and off states, the heat generated is greatly reduced, lowering the heat dissipation requirements. Electromagnetic noise is filtered out using high-pass and band-pass filters for clearer sound. The power amplifier protection circuit protects the amplifier by monitoring voltage and current in the circuit. This includes input monitoring, fuse protection, and fault detection. The input monitoring circuit monitors positive or negative voltage at the input terminal. When an abnormality occurs, the relay outputs a high level to prevent circuit damage. Fuse protection: A fuse is connected in series in the power supply circuit. When overcurrent or short circuit occurs, the fuse blows, cutting off the power supply and protecting the power amplifier. Fault detection: If an abnormal voltage is detected and the relay does not engage, it indicates a possible fault in the final stage of the power amplifier, requiring repair.

[0032] The magnetic vibration sensor 8 is electrically connected to the constant current source through the sensor signal input interface 4. The gain resistor adjustment knob 7 is electrically connected to the Class D power amplifier circuit. The external trigger I / O terminal 5 is electrically connected to the input terminal of the power amplifier protection circuit. The signal processing board is also provided with a single / dual channel switching circuit. The single / dual channel switching switch 3 is electrically connected to the power amplifier protection circuit through the single / dual channel switching circuit. The output terminal of the power amplifier protection circuit is electrically connected to the audio signal output interface 6. The external trigger I / O terminal 5 can control the playback and stop of the sound of the listening box through the PLC.

[0033] like Figures 3 to 4 As shown, there are two magnetic vibration sensors 8, which are piezoelectric accelerometers 10. The sensor signal input interface 4 has two channels. The two piezoelectric accelerometers 10 are plugged into and plugged into the two sensor signal input interfaces 4 respectively. The two sensor signal input interfaces 4 are BNC interface terminals.

[0034] Two BNC connectors provide 4mA IEPE excitation, and the mode can be switched via a single / dual channel switch. In "SINGLE" mode, the left and right channels of the headphones simultaneously play the CH1 channel signal; in "DUAL" mode, the left and right channels of the headphones simultaneously play the CH1 and CH2 channel signals respectively.

[0035] The speaker box has a built-in dual-channel IEPE constant current source excitation, with a current of 4mA, which can be used to drive the piezoelectric accelerometer 10 to put it into operation. The voltage signal generated by the piezoelectric accelerometer 10 is amplified by a first-stage amplifier circuit, then input to a bandpass filter circuit to filter out high-frequency noise interference, and then connected to a second-stage amplifier circuit. The output signal is sent to the audio signal output interface 6, allowing the user to play audio through headphones.

[0036] In this embodiment, the accelerometer is a piezoelectric accelerometer, which works based on the piezoelectric effect. It is an inertial sensor whose core function is to convert the acceleration signal of mechanical vibration or impact into a measurable electrical signal. It is widely used in vibration monitoring, equipment diagnosis, aerospace and other fields.

[0037] The core components of a piezoelectric accelerometer include an inertial mass and a piezoelectric crystal. The inertial mass senses acceleration and converts it into an inertial force F according to Newton's second law F=ma, which acts on the piezoelectric material. The piezoelectric material receives the stress generated by the inertial force and generates an electric charge through the piezoelectric effect. Then, the electric charge is converted into a voltage signal for output through a built-in amplifier circuit.

[0038] The piezoelectric accelerometer used in this solution is a commercially available unidirectional accelerometer with a range of 50g and a frequency response of 2-10000Hz, suitable for typical industrial applications, such as... Figure 4 As shown.

[0039] like Figure 5 As shown, the magnetic vibration sensor 8 also includes a sleeve 9. The bottom of the sleeve 9 is provided with a receiving cavity 12 and a partition 13. A magnet 11 is provided in the receiving cavity 12. The top of the receiving cavity 12 is fixedly connected to the partition 13. A piezoelectric accelerometer 10 is placed on the partition 13 on the side opposite to the receiving cavity 12. The partition 13 is provided with a through hole. The magnet 11 is provided with a mounting screw. The bottom of the piezoelectric accelerometer 10 is provided with a threaded hole. The mounting screw fixes the magnet 11 and the piezoelectric accelerometer 10 to the two sides of the partition 13 respectively through the through hole. The side wall of the sleeve 9 is also provided with a sensor placement hole 14 and an anti-attenuation hole 15. The sleeve 9 is an aluminum alloy sleeve.

[0040] In this embodiment, the sleeve 9 effectively protects the sensor and facilitates the operator's handling of the sensor. The sleeve 9 is made of 6061 aluminum alloy and is CNC machined. One end of the sleeve 9 is fixed with an annular magnet 11 by an M5 bolt. The bolt passes through a pre-drilled hole to fit the M5 threaded hole at the bottom of the piezoelectric accelerometer 10, thereby fixing the piezoelectric accelerometer 10 onto the sleeve 9.

[0041] Due to its mass, the sleeve 9 attenuates the high-frequency signal acquired by the piezoelectric accelerometer 10. Therefore, the sleeve 9 needs to be made of aluminum alloy and have holes machined in it to effectively reduce the system mass while ensuring strength. CAE finite element analysis shows that the first-order torsional mode of the sleeve 9 in this design is 1175Hz, which has minimal impact on signals below 1000Hz, meeting the requirements of common industrial applications in the 20-1000Hz range. Figure 6 As shown.

[0042] The audio signal output interface 6 is an AUX standard audio interface, which connects to headphones to play back the sensor signal in real time.

[0043] like Figure 7 As shown, the housing 1 contains a battery and a battery management circuit. The battery is electrically connected to the signal processing board through the battery management circuit. The other end of the housing 1 is also provided with a rear operation panel 16. The rear operation panel 16 is provided with a charging interface 19, a power switch 18, and a power display screen 17. The power switch 18, the power display screen 17, and the charging interface 19 are electrically connected to the battery management circuit. The built-in battery is a 10000mAh lithium battery with synchronous power display and a 12-hour battery life on a full charge.

[0044] like Figure 8 As shown, a noise testing bench including a listening box includes a test bench 25. The listening box, a test piece fixing fixture 24, a load motor 21, and a start switch 23 are placed on the test bench 25. An electrical control cabinet 20 is placed at the bottom of the test bench 25. The start switch 23 is electrically connected to the electrical control cabinet 20. The electrical control cabinet 20 is electrically connected to the external trigger I / O terminal 5 on the listening box. The electrical control cabinet 20 is also electrically connected to the load motor 21. The load motor 21 applies a load to the test piece. The test piece fixing fixture 24 clamps the test piece 22. The test piece 22 is electrically connected to the sensor signal input interface 4 on the listening box through a magnetic vibration sensor 8.

[0045] like Figure 9 As shown, the measuring workpiece fixing fixture 24 is provided with a clamping operation handle 27, a moving operation handle 28 and a slide rail 26. The clamping operation handle 27 is used to clamp the workpiece to be measured, and the moving operation handle 28 can push the measuring workpiece fixing fixture 24 to slide on the slide rail 26.

[0046] The process of using the listening box is as follows: place the magnetic vibration sensor 8 on the component to be monitored, insert headphones into the audio signal output interface 6, turn on the power switch 18, and monitor abnormal noises through the headphones.

[0047] The working process of the abnormal noise test bench is as follows: In this embodiment, the workpiece 22 under test is a motor. The workpiece 22 under test is placed on the test piece fixing fixture 24 and tightened. The test piece fixing fixture 24 is pushed to move, so that the workpiece under test is connected to the rotating shaft of the load motor 21. The magnetic vibration sensor 8 is placed on the workpiece 22 under test and electrically connected to the sensor signal input interface 4 on the listening box. At the same time, the PLC output terminal in the electrical control cabinet 20 is electrically connected to the external trigger IO terminal 5 on the listening box. The headphones are inserted into the audio signal output interface 6.

[0048] When the start switch 23 is turned on, the electrical control cabinet 20 controls the load motor 21 to apply a load to the workpiece under test. At the same time, the magnetic vibration sensor 8 converts the vibration signal of the workpiece under test into an electrical signal and inputs it into the listening box, and outputs audio through headphones.

[0049] In this embodiment, the listening box is triggered by the external trigger IO terminal 5 and is compatible with the abnormal noise test bench. After testing a workpiece, the start switch 23 can be turned off so that the external trigger IO terminal does not receive the trigger signal and the listening box stops working. This allows the person being tested to continue testing the workpiece without removing the headphones after testing one workpiece and when measuring the next workpiece, thus improving work efficiency.

[0050] The audio box, paired with an accelerometer, can be widely used in industrial scenarios. By placing the accelerometer in the scene and location that needs to be monitored, engineers wearing headphones can manually determine whether there are any abnormal noises in the scene by converting the audio in real time, and can further assist in determining the source of the abnormal noises.

[0051] Typical application scenarios include 1) Listening to industrial equipment: For example, placing a sensor on the surface of a running motor can determine if there is any abnormal operation. 2) Troubleshooting in the laboratory: Deploying sensors on the surface of moving parts can help identify the source of abnormal vibrations.

[0052] 3) Production environment: Deploy sensors on the surface of parts being produced, such as test parts containing motors, gearboxes, etc., and judge the production quality by listening to their audio.

[0053] The technical means disclosed in this utility model are not limited to those disclosed in the above embodiments, but also include technical solutions composed of any combination of the above technical features. It should be noted that those skilled in the art can make various improvements and modifications without departing from the principle of this utility model, and these improvements and modifications are also considered within the scope of protection of this utility model.

Claims

1. A listening box, characterized in that: The device includes a housing (1), a magnetic vibration sensor (8), and an earphone. A signal processing board is installed inside the housing (1). A front operation panel (2) is installed at one end of the housing (1). The front operation panel (2) is equipped with a sensor signal input interface (4), an audio signal output interface (6), a single / dual channel switch (3), an external trigger IO terminal (5), and a gain resistor adjustment knob (7). The sensor signal input interface (4), the audio signal output interface (6), the single / dual channel switch (3), the external trigger IO terminal (5), and the gain resistor adjustment knob (7) are all electrically connected to the signal processing board. The magnetic vibration sensor (8) is electrically connected to the signal processing board through the sensor signal input interface (4). The earphone is plugged into and plugged into the audio signal output interface (6).

2. The listening box according to claim 1, characterized in that: The listening box also includes a Bluetooth audio transmission module. The earphone is wirelessly connected to the Bluetooth audio transmission module, and the Bluetooth audio transmission module is plugged into and plugged into the audio signal output interface (6).

3. The listening box according to claim 1, characterized in that: The signal processing board is equipped with a constant current source, a high-pass filter, a first-stage amplifier circuit, a band-pass filter, a second-stage amplifier circuit, a Class D power amplifier circuit, and a power amplifier protection circuit. The constant current source is electrically connected to the first-stage amplifier circuit through the high-pass filter. The first-stage amplifier circuit is electrically connected to the second-stage amplifier circuit through the band-pass filter. The second-stage amplifier circuit is electrically connected to the power amplifier protection circuit through the Class D power amplifier circuit.

4. The listening box according to claim 3, characterized in that: The magnetic vibration sensor (8) is electrically connected to the constant current source through the sensor signal input interface (4). The gain resistor adjustment knob (7) is electrically connected to the Class D power amplifier circuit. The external trigger IO terminal (5) is electrically connected to the input terminal of the power amplifier protection circuit. The signal processing board is also provided with a single / dual channel switching circuit. The single / dual channel switching switch (3) is electrically connected to the power amplifier protection circuit through the single / dual channel switching circuit. The output terminal of the power amplifier protection circuit is electrically connected to the audio signal output interface (6).

5. The listening box according to claim 1, characterized in that: The number of magnetic vibration sensors (8) is two, and the two magnetic vibration sensors (8) are piezoelectric accelerometers (10). The sensor signal input interface (4) is two-way. The two piezoelectric accelerometers (10) are plugged and unplugged into the two-way sensor signal input interface (4) respectively. The two-way sensor signal input interface (4) is a BNC interface terminal.

6. The listening box according to claim 5, characterized in that: The magnetic vibration sensor (8) also includes a sleeve (9). The bottom of the sleeve (9) is provided with a receiving cavity (12) and a partition (13). A magnet (11) is provided in the receiving cavity (12). The top of the receiving cavity (12) is fixedly connected to the partition (13). A piezoelectric accelerometer (10) is placed on the partition (13) and on the side opposite to the receiving cavity (12). A through hole is provided on the partition (13). An mounting screw is provided on the magnet (11). A threaded hole is provided at the bottom of the piezoelectric accelerometer (10). The mounting screw fixes the magnet (11) and the piezoelectric accelerometer (10) to both sides of the partition (13) through the through hole. A sensor placement hole (14) and an anti-attenuation hole (15) are also provided on the side wall of the sleeve (9). The sleeve (9) is an aluminum alloy sleeve.

7. The listening box according to claim 1, characterized in that: The audio signal output interface (6) is an AUX standard audio interface.

8. The listening box according to claim 1, characterized in that: The housing (1) is provided with a battery and a battery management circuit. The battery is electrically connected to the signal processing board through the battery management circuit. The other end of the housing (1) is also provided with a rear operation panel (16). The rear operation panel (16) is provided with a charging interface (19), a power switch (18) and a power display screen (17). The power switch (18), the power display screen (17) and the charging interface (19) are electrically connected to the battery management circuit.

9. A noise testing platform comprising the listening box according to any one of claims 1 to 8, characterized in that: The test bench (25) includes a listening box, a test piece fixing fixture (24), a load motor (21), and a start switch (23) placed on the test bench (25). An electrical control cabinet (20) is placed at the bottom of the test bench (25). The start switch (23) is electrically connected to the electrical control cabinet (20). The electrical control cabinet (20) is electrically connected to the external trigger IO terminal (5) on the listening box. The electrical control cabinet (20) is also electrically connected to the load motor (21). The load motor (21) applies a load to the test piece. The test piece fixing fixture (24) clamps the test piece (22). The test piece (22) is electrically connected to the sensor signal input interface (4) on the listening box through a magnetic vibration sensor (8).

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