Multi-frequency point adjustable piston sound generator

Abstract

The application provides a piston sound generator with multiple frequency points, which is characterized in that a closed shell is arranged in the top opening of an outer shell to form a closed environment, a sound generating device is arranged in the closed shell, the sound generating device comprises a cam shell and a cam mechanism in the cam shell, and a closed cavity is formed between the cam shell and the closed shell. When the motor drives the cam mechanism to move, sound pressure is generated in the closed cavity. The rotation speed of the motor is adjustable to realize the adjustment of multiple frequency points. An adjusting part is arranged in clamping connection with the closed shell, the adjusting part can rotate freely relative to the closed shell, a plurality of closed shell through holes with different sizes are arranged in the closed shell, an adjusting part through hole is arranged in the adjusting part, when the rotation speed of the motor is at different values, the adjusting part is rotated to align the closed shell through hole with different sizes and the adjusting part through hole, the arrangement of the closed shell through hole with different sizes enables the gas in the closed shell to exchange with the air outside the piston sound generator, the internal and external air pressures at different frequencies are balanced, and the sound pressure level of the generated sound pressure is stable and not distorted.

Description

Technical Field

[0001] This application relates to the field of acoustic calibration equipment technology, and in particular to a multi-frequency adjustable piston sound generator. Background Technology

[0002] A piston generator is a type of sound calibrator, frequently used to calibrate acoustic devices, such as microphones. The piston generator works by using a motor or other power mechanism to drive a piston to reciprocate within a relatively sealed cavity, thereby changing the pressure inside the cavity and generating a stable sound pressure. This sound pressure is detected by the microphone, and the accuracy and sensitivity of the microphone can be determined by the sound pressure level detected by the microphone. Sound is a pressure fluctuation at atmospheric pressure; the magnitude of this pressure fluctuation is simply called sound pressure, and the magnitude of sound pressure is generally further evaluated using sound pressure level.

[0003] The frequency of a piston-generated sound generator refers to the frequency of the piston's periodic reciprocating motion within the cavity, measured in Hz (Hertz). The frequency of the piston-generated sound generator directly determines the frequency of the sound waves generated by the piston's reciprocating motion. For example, if the piston vibrates 100 times per second, the sound wave frequency is 100Hz. Under ideal conditions (ignoring complex factors such as medium damping and resonance), the frequency of the piston-generated sound generator is consistent with the piston's mechanical vibration frequency. However, in reality, it may be affected by sound field boundary conditions or resonance effects, leading to frequency deviation.

[0004] However, traditional piston generators have a serious drawback: they cannot generate sound pressure levels at different frequencies, meaning they cannot achieve multi-frequency adjustment. The motor speed in traditional piston generators is fixed, which determines the fixed frequency of the generator, thus preventing multi-frequency adjustment. Most commercially available piston generators are fixed at a single frequency of 250Hz. The primary reason is that the sealed shell of traditional piston generators has only a single through-hole connecting the internal and external air pressure. In practice, different frequencies require different sized through-holes, and a mismatch between the through-hole size and the frequency leads to severe sound pressure level distortion, failing to meet sound pressure calibration requirements. Summary of the Invention

[0005] Therefore, it is necessary to provide a multi-frequency adjustable piston generator to address the problems of traditional multi-frequency adjustable piston generators.

[0006] The multi-frequency adjustable piston sound generator includes:

[0007] An outer casing, wherein the outer casing is configured to have a top opening and a hollow interior;

[0008] A closed shell, the bottom of which is embedded in the top opening of the outer shell;

[0009] The motor is located inside the housing;

[0010] A sound-generating device is disposed inside the enclosed shell. The sound-generating device includes a cam shell, inside which a cam mechanism is disposed. A closed cavity is formed between the cam shell and the enclosed shell. The motor is fixedly connected to the cam mechanism. When the motor drives the cam mechanism to move, sound pressure is generated in the closed cavity. The speed of the motor is set to be adjustable.

[0011] An adjusting member is engaged with the closed shell, and the adjusting member is configured to rotate freely relative to the closed shell;

[0012] The adjusting component has an adjusting component through hole, and the closed shell has multiple closed shell through holes of different sizes; when the motor speed is at different values, the adjusting component is rotated to align the closed shell through holes of different sizes with the adjusting component through hole.

[0013] This application provides a multi-frequency adjustable piston generator. A sealed shell is inserted into the top opening of an outer shell, creating a relatively enclosed environment. A sound-generating device and motor are installed within the sealed shell to generate basic sound pressure. The sound-generating device includes a cam shell and a cam mechanism within the cam shell, forming a closed cavity between the cam shell and the sealed shell. When the motor drives the cam mechanism, sound pressure is generated within the closed cavity. By setting the motor speed to be adjustable, the piston generator can achieve multi-frequency adjustment. This application includes an adjusting member that engages with the sealed shell and is designed to rotate freely relative to the sealed shell. The sealed shell has multiple through holes of different sizes, and the adjusting member has one adjusting member through hole. When the motor speed is at different values, rotating the adjusting member aligns the different sized through holes of the sealed shell and the adjusting member through hole. The different sized through holes of the sealed shell allow for gas exchange between the inside of the sealed shell and the outside air of the piston generator, ensuring internal and external air pressure balance at different frequencies, thus guaranteeing a stable and distortion-free sound pressure level. Attached Figure Description

[0014] Figure 1 This is a schematic diagram of the housing of a multi-frequency adjustable piston sounder provided in an embodiment of this application.

[0015] Figure 2 To Figure 1 A cross-sectional view of the multi-frequency adjustable piston sounder after being cut along section line A-A'.

[0016] Figure 3 This is a schematic diagram showing the connection relationship between the motor, connecting mechanism, and sound-generating device in a multi-frequency adjustable piston sound generator provided in an embodiment of this application.

[0017] Figure 4 This is a schematic diagram showing the connection relationship between the closed shell and the connecting boss in a multi-frequency adjustable piston sounder provided in an embodiment of this application.

[0018] Figure 5 This is a schematic diagram of the annular groove and the closed shell through hole in a multi-frequency adjustable piston sounder provided in an embodiment of this application.

[0019] Figure 6 This is a schematic diagram showing the fit between the adjustment member through hole and multiple closed shell through holes of different sizes in a multi-frequency adjustable piston sounder provided in an embodiment of this application.

[0020] Figure 7 This is a schematic diagram of the mounting through-hole and motor connection through-hole in a multi-frequency adjustable piston sounder provided in an embodiment of this application.

[0021] Figure 8 This is a schematic diagram of the intermediate cavity in a multi-frequency adjustable piston sounder provided in an embodiment of this application.

[0022] Figure 9 This is a schematic diagram of the battery compartment housing cavity in a multi-frequency adjustable piston sounder provided in an embodiment of this application.

[0023] Figure 10 This is a schematic diagram showing the connection relationship between the cam, piston, and spring in a multi-frequency adjustable piston sounder provided in an embodiment of this application.

[0024] Figure 11 This is a schematic diagram of the display screen and various buttons in a multi-frequency adjustable piston sounder provided in an embodiment of this application.

[0025] Figure 12 This is a schematic diagram of the first housing and the second housing in a multi-frequency adjustable piston sounder provided in an embodiment of this application.

[0026] Figure 13 This is a schematic diagram of the gap in a multi-frequency adjustable piston sounder provided in an embodiment of this application.

[0027] Figure 14 This is a schematic diagram showing the connection relationship between the microcontroller and various circuits integrated on the circuit board in a multi-frequency adjustable piston sounder provided in an embodiment of this application.

[0028] Figure 15 This is a schematic diagram showing the connection relationship between the first microcontroller crystal oscillator circuit, the second microcontroller crystal oscillator circuit, and the microcontroller in a multi-frequency adjustable piston sound generator provided in an embodiment of this application.

[0029] Figure 16This diagram illustrates the connection relationship between the initial operating state control circuit, the USB debugging circuit, and the microcontroller in a multi-frequency adjustable piston sounder provided in an embodiment of this application.

[0030] Figure 17 This is a schematic diagram showing the connection relationship between the motor interface circuit, the motor power supply circuit, and the microcontroller in a multi-frequency adjustable piston sounder provided in an embodiment of this application.

[0031] Figure 18 This is a schematic diagram showing the connection relationship between the microcontroller power supply circuit and the microcontroller in a multi-frequency adjustable piston sounder provided in an embodiment of this application.

[0032] Figure 19 This is a schematic diagram showing the connection relationship between the microcontroller programming circuit and the microcontroller in a multi-frequency adjustable piston sound generator provided in an embodiment of this application.

[0033] Figure 20 This is a schematic diagram showing the connection relationship between the external test interface and the first power supply in a multi-frequency adjustable piston generator provided in an embodiment of this application.

[0034] Figure label:

[0035] 10 - Outer shell; 110 - First shell; 111 - Button; 111a - Plus button; 111b - Minus button; 111c - Start button; 111d - Stop button;

[0036] 112 - Display screen; 120 - Second housing; 130 - USB interface; 20 - Connection mechanism; 210 - Connector; 211 - Connecting piece; 212 - Connecting boss;

[0037] 213 - First bolt hole; 214 - Second bolt hole; 215 - Boss through hole; 216 - Motor connection through hole; 220 - Connector; 30 - Enclosed shell;

[0038] 310 - Annular groove; 311 - Through hole in closed shell; 320 - Top opening of closed shell; 330 - Bottom opening of closed shell;

[0039] 340 - Central axis of the enclosed housing; 350 - First sealing ring groove; 40 - Motor; 410 - Motor shaft; 50 - Sound-generating device; 510 - Cam housing;

[0040] 511 - Central axis of cam housing; 512 - Mounting through hole; 513 - Top through hole of cam housing; 524 - Large diameter section; 525 - Small diameter section;

[0041] 520 - Cam mechanism; 521 - Central axis of cam mechanism; 522 - Cam; 523 - Receiving part; 530 - Piston; 531 - Protrusion; 532 - Piston groove;

[0042] 540 - Enclosed cavity; 541 - Cam housing cavity; 542 - Intermediate cavity; 550 - Spring; 560 - Sound cover; 561 - Annular end face; 562 - Limiting post;

[0043] 563 - Gap; 564 - Through hole on top of speaker cover; 60 - Adjustment component; 610 - Through hole of adjustment component; 70 - Connecting plate; 721 - Battery compartment;

[0044] 730 - First power supply; 740 - First resistor; 741 - First terminal of the first resistor; 742 - Second terminal of the first resistor; 750 - Second resistor;

[0045] 751 - First terminal of the second resistor; 752 - Second terminal of the second resistor; 760 - Third resistor; 761 - First terminal of the third resistor;

[0046] 762 - The second terminal of the third resistor; 770 - The first light-emitting diode; 771 - The positive terminal of the first light-emitting diode;

[0047] 772 - Cathode of the first LED; 780 - Resistor 23; 790 - Resistor 24; 80 - Microcontroller; 801 - First pin;

[0048] 802 - Pin 2; 803 - Pin 3; 804 - Pin 4; 805 - Pin 5; 806 - Pin 6; 807 - Pin 7;

[0049] 808 - Pin 8; 809 - Pin 9; 810 - Pin 10; 811 - Pin 11; 812 - Pin 12; 813 - Pin 13;

[0050] 814 - Pin 14; 815 - Pin 15; 816 - Pin 16; 817 - Pin 17; 818 - Pin 18;

[0051] 819 - Pin 19; 820 - Pin 20; 821 - Pin 21; 822 - Pin 22; 823 - Pin 23;

[0052] 824 - Pin 24; 825 - Pin 25; 826 - Pin 26; 827 - Pin 27; 828 - Pin 28;

[0053] 829 - Pin 29; 830 - Pin 30; 831 - Pin 31; 832 - Pin 32; 833 - Pin 33;

[0054] 834 - Pin 34; 835 - Pin 35; 836 - Pin 36; 837 - Pin 37; 838 - Pin 38;

[0055] 839 - Pin 39; 840 - Pin 40; 841 - Pin 41; 842 - Pin 42; 843 - Pin 43;

[0056] 844 - Pin 44; 845 - Pin 45; 846 - Pin 46; 847 - Pin 47; 848 - Pin 48;

[0057] 849 - Pin 49; 850 - Pin 50; 851 - Pin 51; 852 - Pin 52; 853 - Pin 53;

[0058] 854 - Pin 54; 855 - Pin 55; 856 - Pin 56; 857 - Pin 57; 858 - Pin 58;

[0059] 859 - Pin 59; 860 - Pin 60; 861 - Pin 61; 862 - Pin 62; 863 - Pin 63;

[0060] 864 - Pin 64; 910 - Microcontroller crystal oscillator circuit; 910a - First microcontroller crystal oscillator circuit; 911 - First capacitor;

[0061] 911a - First plate of the first capacitor; 911b - Second plate of the first capacitor; 912 - Second capacitor; 912a - First plate of the second capacitor;

[0062] 912b - Second plate of the second capacitor; 913 - First crystal oscillator; 913a - First terminal of the first crystal oscillator; 913b - Second terminal of the first crystal oscillator;

[0063] 910b - Second microcontroller crystal oscillator circuit; 914 - Third capacitor; 914a - First plate of the third capacitor; 914b - Second plate of the third capacitor;

[0064] 915 - Fourth capacitor; 915a - First plate of the fourth capacitor; 915b - Second plate of the fourth capacitor; 916 - Second crystal oscillator;

[0065] 916a - First terminal of the second crystal oscillator; 916b - Second terminal of the second crystal oscillator; 920 - Keypad circuit; 921 - FPC socket; 922 - First diode;

[0066] 922a - Positive terminal of the first diode; 922b - Negative terminal of the first diode; 923 - First interface of the button circuit;

[0067] 924 - Second interface of the button circuit; 925 - Third interface of the button circuit; 926 - Fourth interface for button detection;

[0068] 927 - Fifth interface of the button circuit; 930 - Initial operating state control circuit; 931a - Fourth resistor; 931a1 - First terminal of the fourth resistor;

[0069] 931a2 - the second terminal of the fourth resistor; 931b - the fifth resistor; 931b1 - the first terminal of the fifth resistor; 931b2 - the second terminal of the fifth resistor;

[0070] 931c - Sixth resistor; 931c1 - First terminal of the sixth resistor; 931c2 - Second terminal of the sixth resistor; 931d - Seventh resistor;

[0071] 931d1 - Terminal 1 of the seventh resistor; 931d2 - Terminal 2 of the seventh resistor; 931e - The eighth resistor; 931e1 - Terminal 1 of the eighth resistor;

[0072] 931e2 - the second terminal of the eighth resistor; 931f - the ninth resistor; 931f1 - the first terminal of the ninth resistor; 931f2 - the second terminal of the ninth resistor;

[0073] 931g - Tenth resistor; 931g1 - First terminal of the tenth resistor; 931g2 - Second terminal of the tenth resistor; 931h - Eleventh resistor;

[0074] 931h1 - Terminal 1 of the eleventh resistor; 931h2 - Terminal 2 of the eleventh resistor; 931i - Twelfth resistor;

[0075] 931i1 - Terminal 1 of the twelfth resistor; 931i2 - Terminal 2 of the twelfth resistor; 931j - The thirteenth resistor;

[0076] 931j1 - Terminal 1 of the thirteenth resistor; 931j2 - Terminal 2 of the thirteenth resistor; 931k - The fourteenth resistor;

[0077] 931k1 - Terminal 1 of the fourteenth resistor; 931k2 - Terminal 2 of the fourteenth resistor; 932 - Fifteenth resistor;

[0078] 932a - First terminal of the fifteenth resistor; 932b - Second terminal of the fifteenth resistor; 933 - Fifth capacitor; 933a - First plate of the fifth capacitor;

[0079] 933b - the second plate of the fifth capacitor; 934 - the sixth capacitor; 934a - the first plate of the sixth capacitor; 934b - the second plate of the sixth capacitor;

[0080] 935 - Second LED; 935a - Positive terminal of the second LED; 935b - Negative terminal of the second LED;

[0081] 936 - Third LED; 936a - Positive terminal of the third LED; 936b - Negative terminal of the third LED;

[0082] 940-USB debugging circuit; 941-USB debugging circuit chip; 941a-USB debugging circuit chip's first serial port;

[0083] The second serial port of the 941b-USB debug circuit chip; the third serial port of the 941c-USB debug circuit chip;

[0084] The fourth serial port of the 941d-USB debug circuit chip; the fifth serial port of the 941e-USB debug circuit chip;

[0085] The sixth serial port of the 941f-USB debug circuit chip; the sixteenth resistor of the 942-USB debug circuit chip; the first terminal of the sixteenth resistor of the 942a-USB debug circuit chip.

[0086] 942b - the second terminal of the sixteenth resistor; 943 - the seventeenth resistor; 943a - the first terminal of the seventeenth resistor;

[0087] 943b - The second terminal of the seventeenth resistor; 950 - Motor interface circuit; 951 - Interface device; 951a - The first interface of the interface device;

[0088] 951b - Second interface of the interface device; 951c - Third interface of the interface device; 951d - Fourth interface of the interface device; 952 - Eighteenth resistor;

[0089] 952a - Terminal 1 of the 18th resistor; 952b - Terminal 2 of the 18th resistor; 953 - TVS diode; 953a - Terminal 1 of the TVS diode;

[0090] 953b - The second terminal of the TVS diode; 960 - Motor power supply circuit; 961 - Second power supply; 962 - Nineteenth resistor;

[0091] 962a - Terminal 1 of the nineteenth resistor; 962b - Terminal 2 of the nineteenth resistor; 963 - Resistor 20; 963a - Terminal 1 of the twentieth resistor;

[0092] 963b - the second terminal of the twentieth resistor; 964 - the twenty-first resistor; 965 - the twenty-second resistor; 965a - the first terminal of the twenty-second resistor;

[0093] 965b - the second terminal of the twenty-second resistor; 966 - field-effect transistor; 966a - the first terminal of the field-effect transistor; 966b - the second terminal of the field-effect transistor;

[0094] 966c - the third terminal of the field-effect transistor; 967 - the seventh capacitor; 967a - the first plate of the seventh capacitor; 967b - the second plate of the seventh capacitor;

[0095] 968 - First transistor; 968a - Base of first transistor; 968b - Collector of first transistor; 968c - Emitter of first transistor;

[0096] 969 - Second diode; 969a - Positive terminal of the second diode; 969b - Negative terminal of the second diode; 970 - Microcontroller power supply circuit;

[0097] 971a - Eighth capacitor; 971a1 - First plate of the eighth capacitor; 971a2 - Second plate of the eighth capacitor; 971b - Ninth capacitor;

[0098] 971b1 - First plate of the ninth capacitor; 971b2 - Second plate of the ninth capacitor; 971c - Tenth capacitor;

[0099] 971c1 - First plate of the tenth capacitor; 971c2 - Second plate of the tenth capacitor; 971d - Eleventh capacitor;

[0100] 971d1 - First plate of the eleventh capacitor; 971d2 - Second plate of the eleventh capacitor; 971e - Twelfth capacitor;

[0101] 971e1 - First plate of the twelfth capacitor; 971e2 - Second plate of the twelfth capacitor; 971f - Thirteenth capacitor;

[0102] 971f1 - First plate of the thirteenth capacitor; 971f2 - Second plate of the thirteenth capacitor; 971g - Fourteenth capacitor;

[0103] 971g1 - First plate of the fourteenth capacitor; 971g2 - Second plate of the fourteenth capacitor; 971h - Fifteenth capacitor;

[0104] 971h1 - First plate of the fifteenth capacitor; 971h2 - Second plate of the fifteenth capacitor; 971i - Sixteenth capacitor;

[0105] 971i1 - First plate of the sixteenth capacitor; 971i2 - Second plate of the sixteenth capacitor; 972 - Third diode;

[0106] 972a - Positive terminal of the third diode; 972b - Negative terminal of the third diode; 973 - Twenty-fifth resistor; 973a - First terminal of the twenty-fifth resistor;

[0107] 973b - the second terminal of the twenty-fifth resistor; 974 - the twenty-sixth resistor; 974a - the first terminal of the twenty-sixth resistor;

[0108] 974b - the second terminal of the 26th resistor; 980 - microcontroller programming circuit; 981 - second transistor; 981a - base of the second transistor;

[0109] 981b - Collector of the second transistor; 981c - Emitter of the second transistor; 982 - Seventeenth capacitor;

[0110] 982a - First plate of the seventeenth capacitor; 982b - Second plate of the seventeenth capacitor; 983 - Twenty-seventh resistor;

[0111] 983a - Terminal 1 of the 27th resistor; 983b - Terminal 2 of the 27th resistor; 984 - The 28th resistor;

[0112] 984a - Terminal 1 of the 28th resistor; 984b - Terminal 2 of the 28th resistor; 985 - The 29th resistor;

[0113] 985a - First terminal of the 29th resistor; 985b - Second terminal of the 29th resistor; 990 - Mating part; 991 - Through hole of the first mating part;

[0114] 992 - Second mating part through hole; 993 - Second sealing ring groove; 994 - External test interface; 994a - First pin of external test interface;

[0115] 994b - the second pin of the external test interface; 994c - the third pin of the external test interface; 994d - the fourth pin of the external test interface. Detailed Implementation

[0116] This application provides a multi-frequency adjustable piston generator. It should be noted that the multi-frequency adjustable piston generator provided in this application is used in conjunction with acoustic detection equipment. Optionally, the multi-frequency adjustable piston generator provided in this application is used in conjunction with a microphone.

[0117] like Figures 1 to 13As shown, in one embodiment of this application, the multi-frequency adjustable piston sound generator is used in conjunction with a microphone when in use. The multi-frequency adjustable piston sound generator includes a housing 10, a connecting mechanism 20, a sealing shell 30, a motor 40, and a sound-generating device 50.

[0118] like Figure 2 As shown, the outer casing 10 is configured with an open top, a hollow interior, and a closed bottom. The connecting mechanism 20 is disposed inside the outer casing 10. The connecting mechanism 20 is fixedly connected to the inner wall of the outer casing 10. The closed shell 30 is a cylindrical shell. The bottom of the closed shell 30 is embedded in the top opening of the outer casing 10. The bottom of the closed shell 30 and the top of the connecting mechanism 20 are fixedly connected. The top of the closed shell 30 has a top opening 320. The top opening 320 is used to embed the microphone. The motor 40 is disposed inside the outer casing 10. The motor 40 and the bottom of the connecting mechanism 20 are fixedly connected.

[0119] like Figure 2 and Figure 3 As shown, the sound-generating device 50 is disposed inside the enclosed shell 30. The sound-generating device 50 includes a cam shell 510. The cam shell 510 is a cylindrical shell and is fixedly connected to the connecting mechanism 20. A cam mechanism 520 is disposed inside the cam shell 510. A pair of symmetrically arranged pistons 530 are engaged on the wall of the cam shell 510. A closed cavity 540 is formed between the cam shell 510 and the enclosed shell 30. The motor shaft 410 of the motor 40 is fixedly connected to the cam mechanism 520. When the motor shaft 410 rotates, the motor shaft 410 drives the cam mechanism 520 to move, causing the pistons 530 to reciprocate continuously within the closed cavity 540, generating sound pressure. The speed of the motor 40 is adjustable.

[0120] like Figure 5 As shown, the outer ring wall of the closed shell 30 is provided with a concave annular groove 310. The multi-frequency adjustable piston sound generator also includes an adjusting member 60. The adjusting member 60 is annular. The adjusting member 60 is engaged in the annular groove 310. The adjusting member 60 is configured to be able to rotate freely about 360 degrees relative to the closed shell 30 around the central axis of the closed shell 30.

[0121] like Figure 6As shown, the adjusting member 60 has an adjusting member through hole 610. The annular groove 310 of the closed shell 30 has multiple closed shell through holes 311 of different sizes. When the speed of the motor 40 is at different values, the adjusting member 60 is rotated to align the closed shell through holes 311 of different sizes with the adjusting member through hole 610. The diameter of the adjusting member through hole 610 is less than or equal to the diameter of the closed shell through hole 311.

[0122] Specifically, since the motor shaft 410 and the cam mechanism 520 are fixedly connected, the rotational speed of the motor 40 determines the rotational speed of the cam mechanism 520, and the cam rotational speed determines the frequency of the emitted sound. The piston-generator in this embodiment can be adjusted to multiple frequencies, ranging from 20Hz to 315Hz.

[0123] A well-sealed cavity can reduce sound leakage and distortion, thereby providing a stable sound pressure level with low distortion. However, excessive sealing of the enclosure 30 can lead to excessively high air pressure inside the enclosure 540, affecting the normal operation of the piston 530 and causing distortion, sound pressure level loss, or even damage to the piston 530. Therefore, it is necessary to ensure that the enclosure 30 has a certain degree of air permeability while ensuring airtightness. To solve this problem, this embodiment provides an enclosure through-hole 311 on the enclosure 30, which serves to equalize pressure, ensuring that the gas inside the enclosure 540 can exchange with the outside air, thereby maintaining the air pressure balance inside and outside the enclosure 30.

[0124] Different frequencies require different sizes for the through-holes 311 in the sealed shell. It can be understood that the larger the through-hole 311, the greater the amount of air exchanged between the inside and outside of the sealed cavity 540, and vice versa. Therefore, different sizes of through-holes 311 need to be set according to different frequencies. In this embodiment, a concave annular groove 310 is provided on the outer ring wall of the sealed shell 30, and an annular adjusting member 60 is provided to engage in the annular groove 310. The annular adjusting member 60 can rotate freely about 360 degrees around the central axis of the sealed shell 30. Furthermore, multiple through-holes 311 of different sizes are provided in the annular groove 310, while only one adjusting member through-hole 610 is provided on the adjusting member 60. Thus, when the speed of the motor 40 is at different values, the piston generator will produce different frequencies. Rotating the adjusting member 60 aligns the different sizes of the through-holes 311 in the sealed shell with the adjusting member through-hole 610. We can set the desired frequency to calculate the motor speed (40), and then select a closed-shell through-hole 311 that matches the speed. This allows us to adjust the piston generator to different frequencies by rotating the adjusting component 60, aligning the adjusting component's through-hole 610 with the required size of the closed-shell through-hole 311, thus meeting the size requirements of the closed-shell through-hole 311 for different frequencies.

[0125] The piston sound generator is a sound calibrator. When the motor shaft 410 rotates, the motor shaft 410 drives the cam mechanism 520 to move, causing the piston 530 to reciprocate continuously in the closed cavity 540, thereby changing the pressure of the cavity and generating a stable sound pressure, which is generally represented by the symbol P.

[0126] Sound pressure P is a pressure fluctuation at atmospheric pressure. We are more accustomed to using the measure of sound pressure level to measure the magnitude of sound pressure P. The conversion formula between sound pressure P and sound pressure level is shown in Formula 1.

[0127] Formula 1.

[0128] Among them, L p P is the sound pressure level. P0 is the reference sound pressure level, which is a constant with a value of 2 × 10⁻⁶. -5 Pa.

[0129] When the calibration frequency of the piston generator is low, additional corrections are needed to account for the effects of pressure leakage, heat conduction, and viscosity in order to obtain accurate sound pressure within the sealed cavity. The correction values ​​for pressure leakage, heat conduction, and viscosity of the piston generator are denoted as... The actual sound pressure level generated by the piston generator is shown in Formula 2.

[0130] Formula 2.

[0131] Among them, L k L is the sound pressure level actually generated by the piston generator. p The sound pressure level of the piston generator (obtained by microphone detection). These are correction values ​​for pressure leakage, heat conduction, and viscosity of the piston generator.

[0132] The correction values ​​for pressure leakage, heat conduction, and viscosity of the piston generator are calculated using Formula 3.

[0133] Formula 3.

[0134] in, These are correction values ​​for pressure leakage, heat conduction, and viscosity of the piston generator. It is atmospheric static pressure. This is the reference standard air pressure. This is the correction amount for pressure leakage. This is a correction factor for heat conduction.

[0135] The parameters in Formula 1, and the pressure leakage correction amount. It is closely related to the closed shell through-hole 311.

[0136] Pressure leakage correction amount The calculation formula is shown in Formula 4.

[0137] Formula 4.

[0138] in, This is the correction amount for pressure leakage. The frequency of the piston generator. This is the leakage time constant.

[0139] Leakage time constant The calculation formula is shown in Formula 5.

[0140] Formula 5.

[0141] in, This is the leakage time constant. The equivalent acoustic compliance of the gas inside the closed cavity 540. The acoustic resistance of the gas flowing through the closed shell through-hole 311.

[0142] The calculation formula is shown in Formula 6.

[0143] Formula 6.

[0144] in, The equivalent acoustic compliance of the gas inside the closed cavity 540. The volume of the closed cavity is 540. It is the speed of sound at normal temperature and pressure, that is, the speed of sound at 1 standard atmosphere (101.325 kPa) and 25 degrees Celsius. This refers to air density.

[0145] The calculation formula is shown in Formula 7.

[0146] Formula 7.

[0147] in, The acoustic resistance of the gas flowing through the closed shell through-hole 311. The length of the closed shell through hole 311. The radius of the closed shell through hole 311. Let be the angular frequency of the cam. This refers to air density. The viscosity coefficient of air is 1.8 × 10⁻⁶. -5 Pa·s.

[0148] To ensure that the pressure leakage correction is less than 0.03 dB (as required by the standard), the leakage time constant must be adjusted. The numerical value is designed to be greater than or equal to 0.05 seconds.

[0149] The equivalent acoustic compliance of the gas inside the closed cavity 540 It remains almost unchanged under normal temperature and pressure conditions, therefore it can be considered a constant with a value of 1.42672 × 10⁻⁶. -9 .

[0150] In formula 5 It is a known quantity, and It is also a known quantity. If the time required is greater than or equal to 0.05 seconds, then the unknown quantity can be calculated. The value should be greater than or equal to 3.50445 × 10 7 .because The calculation formula is shown in Formula 7. , , There are three variables. and Since they are two constants, we base our decision on... Adjusting to changes and Thus, different groups ( , , Different sizes of closed shell through-holes 311 are formed to adapt to different But these ( , , All of these need to be satisfied. The value is greater than or equal to 3.50445 × 10 7 conditions.

[0151] It is important to note the following in formula 4 And in Formula 7 Not the same parameter, in formula 4 The frequency of the piston generator. In Formula 7... It is the angular frequency of the cam. Greater than Depending on the design of the piston generator, and The numerical relationships also differ. Common piston generator designs... yes 4 times.

[0152] In this embodiment, the speed of the motor 40 is set to be adjustable. In one embodiment of this application, the motor 40 adjusts its speed (hereinafter referred to as "speed") through a PWM signal control method, thereby achieving speed adjustability and enabling the piston generator in this embodiment to achieve multi-frequency adjustable operation. Duty cycle is an important concept in PWM signal control methods. It describes the ratio between the time occupied by the high level and the entire cycle time within a pulse period. Duty cycle is expressed as a percentage, ranging from 0% to 100%. By adjusting the duty cycle, we can achieve fine control of the PWM signal. A 100% duty cycle corresponds to the highest speed, and a 0% duty cycle corresponds to 0 speed. We first give the current speed F1 as an initial speed value, and then determine the target speed F0 that we need to adjust to. Then F1-F0 is the difference between the two. PWM1 is set as the currently used duty cycle, referred to as the current duty cycle. If Fmax is set to the highest speed, then the duty cycle we need to adjust is the target duty cycle PWM0. The value of the target duty cycle PWM0 is... By controlling the output of its I / O pins through a microcontroller, the rotational speed can be controlled if the high-level output time accounts for the same percentage as PWM0 within one pulse cycle.

[0153] Therefore, we calculate the target duty cycle using Formula 8.

[0154] Formula 8.

[0155] Where PWM0 is the target duty cycle, PWM1 is the current duty cycle, F1 is the current speed of motor 40, F0 is the target speed of motor 40, and Fmax is the maximum speed, which corresponds to 100% duty cycle.

[0156] However, in actual operation, there is a certain error between the theoretically calculated values ​​of duty cycle and speed and the actual applied values. Therefore, we introduce a correction value C. This is because when using the target duty cycle PWM0, we may not be able to obtain the final corresponding target speed F0. The correction value C is an empirical value obtained through multiple adjustments at various speed points through actual testing.

[0157] Therefore, we adjusted Formula 8 to produce Formula 9, and we use Formula 9 to calculate the corrected target duty cycle.

[0158] Formula 9.

[0159] Among them, PWM aThe corrected target duty cycle is defined as follows: PWM0 is the target duty cycle (i.e., the target duty cycle before correction), PWM1 is the current duty cycle, F1 is the current speed of motor 40, F0 is the target speed of motor 40, Fmax is the highest speed, i.e., the speed corresponding to 100% duty cycle, and C is the correction value.

[0160] After calculating the corrected target duty cycle using Formula 9, we still need to maintain the stable speed of motor 40 using the FG feedback signal. Specifically, we output a square wave signal from inside motor 40, which is the FG signal. The frequency of the square wave signal is used to obtain the new current speed F2 of the motor. Then, F2 replaces F1 in Formula 9 to obtain the new PWM. a Next time, we get the new current speed F3, then replace F2 in formula 9 with F3, and then get the new PWM. a And so on, so that each time we output a new PWM... a Previously, a new current speed was obtained in real time by receiving square wave signals to replace the current speed in Formula 9, thereby keeping the speed of motor 40 stable.

[0161] like Figure 3 and Figure 4 As shown, in one embodiment of this application, the connecting mechanism 20 includes a connecting seat 210 and at least two connecting members 220. The connecting seat 210 includes a connecting piece 211 and a connecting boss 212.

[0162] The connecting boss 212 is disposed on the top of the connecting piece 211, and the connecting boss 212 and the connecting piece 211 are fixedly connected. Two connecting members 220 are respectively disposed on both sides of the connecting piece 211. Each connecting member 220 is fixedly connected to the connecting piece 211. Each connecting member 220 is fixedly connected to the inner wall of the outer casing 10.

[0163] Specifically, each side of the connecting piece 211 may be provided with a plurality of first bolt holes 213, and the connecting member 220 is bolted to the connecting piece 211 through the first bolt holes 213. The connecting member 220 may be provided with a plurality of second bolt holes 214, and the connecting piece 211 is bolted to the inner wall of the outer casing 10 through the second bolt holes 214.

[0164] The connecting piece 211 and the connecting boss 212 can be integrally formed.

[0165] Optionally, the connecting boss 212 is a cylinder with a boss through hole 215 at its axis. The boss through hole 215 also penetrates the connecting piece 211, allowing the motor shaft 410 of the motor 40 to pass through the boss through hole 215 and be fixedly connected to the cam mechanism 520 inside the cam housing 510. The cam mechanism 520 includes a cam 522 and a receiving member 523. The cam 522 and the receiving member 523 can be integrally formed to constitute the cam mechanism 520. The receiving member 523 is a hollow cylindrical shell. The motor shaft 410 of the motor 40 passes through the boss through hole 215 and extends into the interior of the receiving member 523, where it is fixedly connected to the inner wall of the receiving member 523.

[0166] like Figure 7 As shown. The connecting boss 212 also has multiple motor 40 connecting through holes 216, which penetrate the connecting piece 211. The motor 40 is fixedly connected to the connecting mechanism 20 through the multiple motor 40 connecting through holes 216. This achieves a stable connection between the motor 40, the connecting mechanism 20, and the cam mechanism 520. Without the additional fixing points provided by the motor 40 connecting through holes 216, the rotation of the motor shaft 410 would be very unstable simply by fixing it to the cam mechanism 520. Optionally, the motor 40 connecting through holes 216 can be bolt holes, and the motor 40 is bolted to the connecting mechanism 20 through the multiple motor 40 connecting through holes 216.

[0167] In this embodiment, by providing a connecting mechanism 20 composed of a connecting piece 211 and a connecting boss 212, the connecting mechanism 20 has a two-stage structure with a connection gradient, allowing the numerous and complex components and motors 40 in the sound-generating device 50 to be stably connected together through the connecting mechanism 20. By providing a connector 220, the connecting mechanism 20 is fixedly connected to the inner wall of the outer casing 10 through the connector 220.

[0168] like Figure 2 As shown, in one embodiment of this application, the bottom of the closed shell 30 is provided with a bottom opening 330. An internal thread is provided on the inner annular wall of the bottom opening 330. The bottom opening 330 and the connecting seat 210 are threadedly connected.

[0169] Specifically, optionally, the connecting boss 212 is provided with an external thread, and the threaded connection between the closed shell 30 and the connecting mechanism 20 is realized through the cooperation between the external thread on the connecting boss 212 and the internal thread of the bottom opening 330 of the closed shell.

[0170] In this embodiment, an internal thread is provided on the inner ring wall of the bottom opening 330 of the closed shell, so that the bottom opening 330 of the closed shell and the connecting seat 210 are threadedly connected, thereby allowing the closed shell 30 to tightly seal the top of the connecting mechanism 20, thus forming a relatively sealed cavity 540 inside the closed shell 30.

[0171] like Figure 10 As shown, in one embodiment of this application, two pistons 530 are provided, both of which are embedded in the cam housing 510. The two pistons 530 are disposed on both sides of the cam mechanism 520. One end of each piston 530 is provided with a protrusion 531, which engages with the circular contour surface of the cam mechanism 520. The other end of each piston 530 is provided with a piston groove 532.

[0172] Specifically, the two pistons 530 are arranged in a centrally symmetrical manner about the physical center of the cam mechanism 520.

[0173] like Figure 10 As shown, in one embodiment of this application, the sound-generating device further includes a spring 550. The central axis 521 of the cam mechanism, the central axis 511 of the cam housing, and the central axis 340 of the closed housing are the same central axis. Two mounting through holes 512 are symmetrically arranged on the cam housing 510 along the central axis 511 of the cam housing. One end of the spring 550 extends into one mounting through hole 512 and abuts against the groove surface of the piston groove 532 inside a piston 530. The other end of the spring 550 extends into the other mounting through hole 512 and abuts against the groove surface of the piston groove 532 inside another piston 530.

[0174] Specifically, the function of spring 550 is to limit the displacement of the two pistons 530 in other directions during their movement. Specifically, spring 550 limits the two pistons 530 to always conform to the side profile of the rotating cam 522, thereby generating a stable displacement. This displacement is generated by the reciprocating motion between two directions: towards the central axis 521 of the cam mechanism and away from the central axis 521 of the cam mechanism.

[0175] like Figure 3As shown, in one embodiment of this application, the cam housing 510 includes a large-diameter portion 524 and a small-diameter portion 525 connected to each other. The large-diameter portion 524 is a cylindrical shell that is closed at the top, open at the bottom, and hollow inside. The small-diameter portion 525 is a cylindrical shell that is open at both the top and bottom and hollow inside. The diameter of the large-diameter portion 524 is larger than the diameter of the small-diameter portion 525. The large-diameter portion 524 and the small-diameter portion 525 are fixedly connected, and the interiors of the large-diameter portion 524 and the small-diameter portion 525 are interconnected, so that the large-diameter portion 524 and the small-diameter portion 525 form a complete cam housing 510. Optionally, the large-diameter portion 524 and the small-diameter portion 525 are integrally formed.

[0176] The small-diameter portion 525 of the cam housing 510 is fixedly connected to the wall of the boss through hole 215, thus achieving a fixed connection between the cam housing 510 and the connecting mechanism 20. Optionally, the outer circumferential surface of the small-diameter portion 525 of the cam housing 510 is provided with external threads, and the wall of the boss through hole 215 is provided with internal threads. The small-diameter portion 525 of the cam housing 510 and the boss through hole 215 are threadedly connected, so that the cam housing 510 is mounted on the connecting seat 210.

[0177] In this embodiment, the displacement of the two pistons 530 during movement can be limited by setting a spring 550.

[0178] like Figure 3 As shown, in one embodiment of this application, the top of the cam housing 510 is provided with a cam housing top through hole 513.

[0179] Specifically, in this embodiment, a cam housing top through hole 513 is formed on the top of the cam housing 510. The cam housing top through hole 513 is a connecting hole.

[0180] In this embodiment, a cam housing top through hole 513 is opened at the top of the cam housing 510. The function of the cam housing top through hole 513 is to accommodate connecting devices such as bolts.

[0181] like Figure 8 As shown, in one embodiment of this application, the sound-generating device 50 further includes a sound cover 560. The sound cover is disposed outside the cam housing 510. The sound cover 560 is located between the closed housing 30 and the cam housing 510. The sound cover 560 is fixedly connected to the connecting mechanism 20. The sound cover 560 is configured as a hollow cylindrical shell with a closed top end and an open bottom end. The closed top end has a sound cover top through hole 564, which communicates with the cam housing top through hole 513.

[0182] Specifically, the top through hole 564 of the sound cover and the top through hole 513 of the cam housing are connected. Bolts can be inserted into the top through hole 564 of the sound cover and the top through hole 513 of the cam housing to fix the sound cover 560 and the cam housing 510 together.

[0183] In this embodiment, by setting a sound shield 560, the sound shield 560 can shield the noise generated by the movement of the piston 530 and the reset of the spring 550 at different frequencies.

[0184] like Figure 13 As shown, in one embodiment of this application, the bottom opening end forms an annular end face 561 composed of the shell wall thickness. A plurality of axially spaced limiting posts 562 are provided on the annular end face 561. The top surface of each limiting post 562 is fixedly connected to the annular end face 561. The bottom surface of each limiting post 562 is fixedly connected to the top surface of the connecting boss 212, so that the sound cover 560 is fixedly connected to the connecting mechanism 20 through the limiting posts 562.

[0185] The limiting post 562 has a height to create a gap 563 between the annular end face 561 of the sound cover 560 and the top surface of the connecting boss 212. The height of the limiting post 562 can be within a range of greater than or equal to 1 mm and less than or equal to 3 mm.

[0186] The cavity formed inside the cam housing 510 is called the cam housing cavity 541. The cavity between the closed housing 30 and the cam housing 510 is called the intermediate cavity 542. The cam housing cavity 541 and the intermediate cavity 542 are connected by the gap 563. The cam housing cavity 541, the gap 563, and the intermediate cavity 542 together form the closed cavity 540.

[0187] Specifically, such as Figure 13 As shown, the annular end face 561 is a flat lower surface perpendicular to the central axis 511 of the cam housing. Due to the height of the limiting post 562, a gap 563 is created between the annular end face 561 of the sound cover 560 and the top surface of the connecting boss 212.

[0188] like Figure 13 As shown, there is a gap 563 between each pair of adjacent limiting posts 562, which makes the cam housing cavity 541 and the intermediate cavity 542 connected.

[0189] In this embodiment, by setting a limiting post 562 between the sound cover 560 and the connecting boss 212, a gap 563 is generated between the annular end face 561 of the sound cover 560 and the top surface of the connecting boss 212, so that the cam housing cavity 541 and the intermediate cavity 542 are connected, and air can flow effectively between the cam housing cavity 541 and the intermediate cavity 542 to maintain consistent air pressure, thereby reducing the distortion of the sound pressure level.

[0190] like Figure 2 As shown, in one embodiment of this application, the multi-frequency adjustable piston sound generator further includes a mating part 990. When the mating part 990 is in use, the mating part 990 is embedded in the top opening 320 of the closed shell and locked at the top opening 320 of the closed shell.

[0191] Specifically, the mating component 990 has a first mating component through hole 991 and a second mating component through hole 992 that are interconnected. When the mating component 990 is inserted into the top opening 320 of the closed shell, the second mating component through hole 992 communicates with the top opening 320 of the closed shell. The microphone can be inserted into the first mating component through hole 991.

[0192] The diameter of the second mating part through hole 992 is smaller than the diameter of the first mating part through hole 991, and the diameter of the first mating part through hole 991 is smaller than the diameter of the top opening 320 of the closed shell. The function of the second mating part through hole 992 is to limit the microphone, so that the microphone does not extend excessively into the closed cavity 540.

[0193] Optionally, the top opening 320 of the closed shell is further provided with a first sealing ring groove 350 recessed away from the central axis of the closed shell 30. The first sealing ring groove 350 is used to accommodate the first sealing ring (not shown in the figure) to enhance the sealing of the mating part 990 and the top opening 320 of the closed shell.

[0194] Optionally, the first mating part through hole 991 is further provided with a second sealing ring groove 993 recessed in the direction away from the central axis of the closed shell 30. The second sealing ring groove 993 is used to accommodate the second sealing ring (not shown in the figure) to enhance the sealing of the mating part 990 and the microphone engagement, that is, to ensure that the microphone can be locked when it is embedded in the first mating part through hole 991.

[0195] In this embodiment, by providing the mating part 990, the piston microphone can be used with microphones of different sizes. When the microphone is large, the mating part 990 is not used, and the microphone is directly embedded into the top opening 320 of the closed housing. When the microphone is small, the mating part 990 is embedded into the top opening 320 of the closed housing, and then the microphone is embedded into the mating part 990 for use.

[0196] like Figure 9 As shown, in one embodiment of this application, the multi-frequency adjustable piston sound generator further includes a connecting plate 70, a circuit board, and a battery compartment 721.

[0197] The connecting plate 70 divides the accommodating space within the housing 10 at the bottom of the connecting mechanism 20 into control device accommodating cavities (since these are hollow cavities, they are difficult to label). Figure 9 (Unlabeled) and the battery compartment cavity (difficult to label because it is an empty cavity). Figure 9 (Unmarked).

[0198] The circuit board is disposed within the control device receiving cavity, and the circuit board (not shown in the figure) is fixedly connected to the connecting plate 70. The battery compartment 721 is disposed within the battery compartment receiving cavity.

[0199] Specifically, the battery compartment 721 can hold lithium batteries or dry cell batteries. The circuit board can be a PCB board.

[0200] In this embodiment, by setting up the control device accommodating cavity and the battery compartment accommodating cavity, the piston generator can not only accommodate the power supply battery, but also the connecting plate 70 and the circuit board to complete the control of the motor 40 speed and other control functions.

[0201] like Figure 14 As shown, in one embodiment of this application, the multi-frequency adjustable piston sound generator further includes a microcontroller 80, at least one microcontroller crystal oscillator circuit 910, a button circuit 920, an initial working state control circuit 930, a USB debugging circuit 940, a motor interface circuit 950, a motor power supply circuit 960, a microcontroller power supply circuit 970, and a microcontroller programming circuit 980.

[0202] Specifically, the microcontroller 80 includes a first pin 801 to a sixty-fourth pin 864.

[0203] like Figure 15As shown, the microcontroller crystal oscillator circuit 910 includes a first microcontroller crystal oscillator circuit 910a and a second microcontroller crystal oscillator circuit 910b. The first microcontroller crystal oscillator circuit 910a includes a first capacitor 911, a second capacitor 912, and a first crystal oscillator 913. The first terminal 913a of the first crystal oscillator 913 is electrically connected to the fifth pin 805. The first plate 911a of the first capacitor 911 is grounded, and the second plate 911b of the first capacitor 911 is electrically connected to the connection link between the first terminal 913a of the first crystal oscillator 913 and the fifth pin 805. The first plate 911a of the first capacitor 911 is electrically connected to the connection link between the first plate 912a of the second capacitor 912 and ground, and the second plate 912b of the second capacitor 912 is electrically connected to the second terminal 913b of the first crystal oscillator 913. The second plate 912b of the second capacitor 912 is also electrically connected to the sixth pin 806.

[0204] like Figure 15 As shown, the second single-channel microcontroller crystal oscillator 910b includes a third capacitor 914, a fourth capacitor 915, and a second crystal oscillator 916. The first plate 914a of the third capacitor 914 is grounded, and the second plate 914b of the third capacitor 914 is electrically connected to the third pin 803. The first plate 915a of the fourth capacitor 915 is electrically connected to the connection link between the first plate 914a of the third capacitor 914 and ground, and the second plate 915b of the fourth capacitor 915 is electrically connected to the fourth pin 804. The first terminal 916a of the second crystal oscillator 916 is electrically connected to the connection link between the second plate 914b of the third capacitor 914 and the third pin 803. The second terminal 916b of the second crystal oscillator 916 is electrically connected to the connection link between the second plate 915b of the fourth capacitor 915 and the fourth pin 804.

[0205] like Figure 15 As shown, the button circuit 920 includes an FPC socket 921 and a first diode 922. The first interface 923 of the button circuit 920 is grounded, and the second interface 924 of the button circuit 920 is electrically connected to the negative terminal 922b of the first diode 922. The positive terminal 922a of the first diode 922 is electrically connected to the tenth pin 810. The second interface 924 of the button circuit 920 is a KEY-ENTERR signal interface. The third interface 925 of the button circuit 920 is a KEY-RIGHT signal interface, which is connected to the twenty-fourth pin 824. The fourth interface 926 of the button circuit 920 is a KEY-ADD signal interface, which is connected to the twenty-fifth pin 825. The fifth interface 927 of the button circuit 920 is a KEY-EXIT signal interface, which is connected to the eleventh pin 811.

[0206] like Figure 15As shown, the circuit board also integrates a first power supply 730, a first resistor 740, a second resistor 750, a third resistor 760, and a first light-emitting diode 770. The first terminal 751 of the second resistor 750 is electrically connected to the first power supply 730, and the second terminal 752 of the second resistor 750 is electrically connected to the twenty-fifth pin 825. The first terminal 741 of the first resistor 740 is electrically connected to the connection link between the first power supply 730 and the second resistor 750. The second terminal 742 of the first resistor 740 is electrically connected to the twenty-fourth pin 824. The positive terminal 771 of the first light-emitting diode 770 is electrically connected to the connection link between the first power supply 730 and the second resistor 750, the negative terminal 772 of the first light-emitting diode 770 is electrically connected to the first terminal 761 of the third resistor 760, and the second terminal 762 of the third resistor 760 is electrically connected to the fortieth pin 840.

[0207] like Figure 16 As shown, the initial operating state control circuit 930 includes a fourth resistor 931a, a fifth resistor 931b, a sixth resistor 931c, a seventh resistor 931d, an eighth resistor 931e, a ninth resistor 931f, a tenth resistor 931g, an eleventh resistor 931h, a twelfth resistor 931i, a thirteenth resistor 931j, a fourteenth resistor 931k, a fifteenth resistor 932, a fifth capacitor 933, a sixth capacitor 934, a second light-emitting diode 935, and a third light-emitting diode 936.

[0208] like Figure 16 As shown, the first terminal 931a1 of the fourth resistor 931a is electrically connected to the first terminal 931i1 of the twelfth resistor 931i, and the second terminal 931i2 of the twelfth resistor 931i is electrically connected to the fourteenth pin 814. The first terminal 931b1 of the fifth resistor 931b is electrically connected to the second terminal 931a2 of the fourth resistor 931a. The second terminal 931b2 of the fifth resistor 931b is electrically connected to the USB debugging circuit 940.

[0209] The first terminal 931g1 of the tenth resistor 931g is electrically connected to the connection link between the first terminal 931i1 of the fourth resistor 931a and the twelfth resistor 931i. The second terminal 931g2 of the tenth resistor 931g is electrically connected to the first terminal 931h1 of the eleventh resistor 931h. The second terminal 931h2 of the eleventh resistor 931h is electrically connected to the connection link between the second terminal 931b2 of the fifth resistor 931b and the USB debugging circuit 940.

[0210] The first plate 933a of the fifth capacitor 933 is electrically connected to the connection link between the second terminal 931a2 of the fourth resistor 931a and the first terminal 931b1 of the fifth resistor 931b. The second plate 933b of the fifth capacitor 933 is electrically connected to the connection link between the second terminal 931b2 of the fifth resistor 931b and the second terminal 931h2 of the eleventh resistor 931h.

[0211] The first terminal 931c1 of the sixth resistor 931c is electrically connected to the connection link between the first terminal 931a1 of the fourth resistor 931a and the first terminal 931i1 of the twelfth resistor 931i. The second terminal 931c2 of the sixth resistor 931c is electrically connected to the first terminal 931d1 of the seventh resistor 931d. The second terminal 931d2 of the seventh resistor 931d is electrically connected to the connection link between the second terminal 931b2 of the fifth resistor 931b and the second terminal 931h2 of the eleventh resistor 931h.

[0212] The first plate 934a of the sixth capacitor 934 is electrically connected to the connection link between the second terminal 931c2 of the sixth resistor 931c and the first terminal 931d1 of the seventh resistor 931d. The second plate 934b of the sixth capacitor 934 is electrically connected to the connection link between the second terminal 931b2 of the fifth resistor 931b and the second terminal 931h2 of the eleventh resistor 931h.

[0213] The first terminal 931e1 of the eighth resistor 931e is electrically connected to the connection link between the first terminal 931a1 of the fourth resistor 931a and the first terminal 931i1 of the twelfth resistor 931i. The second terminal 931e2 of the eighth resistor 931e is electrically connected to the first terminal 931f1 of the ninth resistor 931f. The second terminal 931f2 of the ninth resistor 931f is electrically connected to the connection link between the second terminal 931b2 of the fifth resistor 931b and the second terminal 931h2 of the eleventh resistor 931h.

[0214] Point A is provided on the connection link between the first terminal 931g1 of the tenth resistor 931g and the first terminal 931i1 of the twelfth resistor 931i. The first power supply 730 can be a 3V power supply.

[0215] The first power supply 730, the positive terminal 935a of the second LED 935, the first terminal 931i1 of the twelfth resistor 931i, and the first terminal 931g1 of the tenth resistor 931g are electrically connected to the same point, i.e., point A. The first terminal 931j1 of the thirteenth resistor 931j is electrically connected to the connection link between point A and the second LED 935. The second terminal 931j2 of the thirteenth resistor 931j is electrically connected to the fifteenth pin 815. The negative terminal 935b of the second LED 935 is electrically connected to the first terminal 932a of the fifteenth resistor 932, and the second terminal 932b of the fifteenth resistor 932 is electrically connected to the forty-third pin 843. The positive terminal 936a of the third LED 936 is electrically connected to the connection link between point A and the first terminal 931j1 of the thirteenth resistor 931j. The negative terminal 936b of the third LED 936 is electrically connected to the first terminal 931k1 of the fourteenth resistor 931k. The second terminal 931k2 of the fourteenth resistor 931k is electrically connected to the forty-second pin 842.

[0216] The USB debugging circuit 940 includes a USB debugging circuit chip 941, a sixteenth resistor 942, and a seventeenth resistor 943. The first serial port 941a of the USB debugging circuit chip 941 is electrically connected to the first terminal 942a of the sixteenth resistor 942, and the second terminal 942b of the sixteenth resistor 942 is electrically connected to the forty-fourth pin 844. The sixth serial port 941f of the USB debugging circuit chip 941 is electrically connected to the connection link between the second terminal 942b of the sixteenth resistor 942 and the forty-fourth pin 844. The second serial port 941b of the USB debugging circuit chip 941 is electrically connected to the second terminal 931b2 of the fifth resistor 931b. The second serial port 941b of the USB debugging circuit chip 941 is also grounded. The fourth serial port 941d of the USB debugging circuit chip 941 is electrically connected to the forty-fifth pin 845. The third serial port 941c of the USB debugging circuit chip 941 is electrically connected to the first terminal 943a of the seventeenth resistor 943, and the second terminal 943b of the seventeenth resistor 943 is electrically connected to the connection link between the fourth serial port 941d and the forty-fifth pin 845 of the USB debugging circuit chip 941.

[0217] The first serial port 943a of the USB debugging circuit chip 941 is connected to the USB DM signal line. The third serial port 943c of the USB debugging circuit chip 941 is connected to the USB DP signal line. The fifth serial port 941e of the USB debugging circuit chip 941 is unused and is a spare serial port.

[0218] like Figure 17 As shown, the motor interface circuit 950 includes an interface device 951, an eighteenth resistor 952, and a TVS diode 953.

[0219] like Figure 17As shown, the motor power supply circuit 960 includes a second power supply 961, a nineteenth resistor 962, a twentieth resistor 963, a twenty-first resistor 964, a twenty-second resistor 965, a field-effect transistor 966, a seventh capacitor 967, a first transistor 968, and a second diode 969. The second power supply 961 can be a 12V power supply.

[0220] The second power supply 961 is electrically connected to the first terminal 962a of the nineteenth resistor 962. The first terminal 966a of the field-effect transistor 966 is electrically connected to the connection link between the second power supply 961 and the first terminal 962a of the nineteenth resistor 962. The second terminal 966b of the field-effect transistor 966 is electrically connected to the first interface 951a of the interface device 951. The third terminal 966c of the field-effect transistor 966 is electrically connected to the first terminal 963a of the twentieth resistor 963. The second terminal 962b of the nineteenth resistor 962 is electrically connected to the connection link between the third terminal 966c of the field-effect transistor 966 and the first terminal 963a of the twentieth resistor 963, and the second terminal 963b of the twentieth resistor 963 is electrically connected to the collector 968b of the first transistor 968. One end of the twenty-first resistor 964 is electrically connected to the base 968a of the first transistor 968. The other end of the twenty-first resistor 964 is connected to the MOTO PWM signal line. The emitter 968c of the first transistor 968 is grounded. The first terminal 965a of the twenty-second resistor 965 is electrically connected to the connection link between the twenty-first resistor 964 and the base 968a of the first transistor 968. The cathode 969b of the second diode 969 is electrically connected to the connection link between the second terminal 966b of the field-effect transistor 966 and the first interface 951a of the interface device 951. The anode 969a of the second diode 969 is electrically connected to the second terminal 965b of the twenty-second resistor 965.

[0221] The first plate 967a of the seventh capacitor 967 is electrically connected to the connection link between the second terminal 966b of the field-effect transistor 966 and the first interface 951a of the interface device 951. The second plate 967b of the seventh capacitor 967 is electrically connected to the connection link between the second terminal 965b of the twenty-second resistor 965 and the positive terminal 969a of the second diode 969.

[0222] The second interface 951b of interface device 951 is electrically connected to the first terminal 952a of the eighteenth resistor 952, and the second terminal 952b of the eighteenth resistor 952 is electrically connected to the fifty-fifth pin 855. The third interface 951c of interface device 951 is the MOTO PWM signal interface. The fifty-fourth pin 854 is unused (not shown in the figure) and is used as a spare interface. The first terminal 953a of TVS diode 953 is electrically connected to the connection link between the second terminal 952b of the eighteenth resistor 952 and the fifty-fifth pin 855. The second terminal 953b of TVS diode 953 is grounded.

[0223] The fourth interface 951d of interface device 951 is electrically connected to the connection link between the second terminal 953b of TVS diode 953 and ground. The circuit board integrates a twenty-third resistor 780 and a twenty-fourth resistor 790. One end of the twenty-third resistor 780 is electrically connected to pin 835 (thirty-fifth pin). One end of the twenty-fourth resistor 790 is electrically connected to pin 836 (thirty-sixth pin). The other end of the twenty-third resistor 780 is connected to the DOUT signal line. The other end of the twenty-fourth resistor 790 is connected to the DIN signal line.

[0224] like Figure 18 As shown, the microcontroller power supply circuit 970 includes an eighth capacitor 971a, a ninth capacitor 971b, a tenth capacitor 971c, an eleventh capacitor 971d, a twelfth capacitor 971e, a thirteenth capacitor 971f, a fourteenth capacitor 971g, a fifteenth capacitor 971h, a sixteenth capacitor 971i, a third diode 972, a twenty-fifth resistor 973, and a twenty-sixth resistor 974.

[0225] The first pin 801 is electrically connected to the negative terminal 972b of the third diode 972, and the positive terminal 972a of the third diode 972 is electrically connected to the first plate 971h1 of the fifteenth capacitor 971h. The second plate 971h2 of the fifteenth capacitor 971h is grounded.

[0226] Pin 812 is electrically connected to the first plate 971a1 of the eighth capacitor 971a, and the second plate 971a2 of the eighth capacitor 971a is electrically connected to the connection link between pin 801 and the third diode 972.

[0227] The first terminal 973a of the 25th resistor 973 is electrically connected to the 13th pin 813. The second terminal 973b of the 25th resistor 973 is electrically connected to the connection link between the positive terminal 972a of the third diode 972 and the first plate 971h1 of the 15th capacitor 971h.

[0228] The first terminal 974a of the twenty-sixth resistor 974 is electrically connected to the seventh pin 807, and the second terminal 974b of the twenty-sixth resistor 974 is electrically connected to the connection link between the positive terminal 972a of the third diode 972 and the first plate 971h1 of the fifteenth capacitor 971h.

[0229] The first plate 971b1 of the ninth capacitor 971b is electrically connected to the connection link between the twelfth pin 812 and the first plate 971a1 of the eighth capacitor 971a. The second plate 971b2 of the ninth capacitor 971b is electrically connected to the connection link between the first terminal 973a of the twenty-fifth resistor 973 and the thirteenth pin 813.

[0230] The first plate 971c1 of the tenth capacitor 971c is electrically connected to the connection link between the twenty-sixth resistor 974 and the seventh pin 807. The second plate 971c2 of the tenth capacitor 971c is grounded.

[0231] Pin 818 is electrically connected to the connection link between the second plate 971c2 of the tenth capacitor 971c and ground.

[0232] Pin 831 is electrically connected to the connection link between the second plate 971c2 of the tenth capacitor 971c and ground.

[0233] Pin 47 (847) is electrically connected to the connection link between the second plate 971c2 of the tenth capacitor 971c and ground.

[0234] Pin 63 (863) is electrically connected to the connection link between the second plate 971c2 of the tenth capacitor 971c and ground.

[0235] Pin 819 is electrically connected to the connection link between the positive terminal 972a of the third diode 972 and the first plate 971h1 of the fifteenth capacitor 971h. Pin 832 is electrically connected to the connection link between pin 819 and the first plate 971h1 of the fifteenth capacitor 971h.

[0236] Pin 48, 848, is electrically connected to the connection link between pin 19, 819, and the first plate 971h1 of capacitor 971h. Pin 64, 864, is electrically connected to the connection link between pin 19, 819, and the first plate 971h1 of capacitor 971h.

[0237] The first plate 971d1 of the eleventh capacitor 971d is electrically connected to the connection link between pin 819 of the nineteenth capacitor and the first plate 971h1 of the fifteenth capacitor 971h. The second plate 971d2 of the eleventh capacitor 971d is electrically connected to the connection link between the second plate 971h2 of the fifteenth capacitor 971h and ground. The first plate 971e1 of the twelfth capacitor 971e is electrically connected to the connection link between pin 819 of the nineteenth capacitor and the first plate 971h1 of the fifteenth capacitor 971h. The second plate 971e2 of the twelfth capacitor 971e is electrically connected to the connection link between the second plate 971h2 of the fifteenth capacitor 971h and ground. The first plate 971f1 of the thirteenth capacitor 971f is electrically connected to the connection link between pin 819 of the nineteenth capacitor and the first plate 971h1 of the fifteenth capacitor 971h. The second plate 971f2 of the thirteenth capacitor 971f2 is electrically connected to the connection link between the second plate 971h2 of the fifteenth capacitor 971h and ground.

[0238] The first plate 971g1 of the fourteenth capacitor 971g is electrically connected to the connection link between pin 819 of the nineteenth capacitor and the first plate 971h1 of the fifteenth capacitor 971h. The second plate 971g2 of the fourteenth capacitor 971g is electrically connected to the connection link between the second plate 971h2 of the fifteenth capacitor 971h and ground. The first plate 971i1 of the sixteenth capacitor 971i is electrically connected to pin 830 of the thirtieth capacitor. The second plate 971i2 of the sixteenth capacitor 971i is electrically connected to the connection link between the second plate 971h2 of the fifteenth capacitor 971h and ground. The first power supply 730 is electrically connected to the connection link between the positive terminal 972a of the third diode 972 and the first plate 971h1 of the fifteenth capacitor 971h.

[0239] like Figure 19 As shown, the microcontroller programming circuit 980 includes a second transistor 981, a seventeenth capacitor 982, a twenty-seventh resistor 983, a twenty-eighth resistor 984, and a twenty-ninth resistor 985. The collector 981b of the second transistor 981 is connected to the sixtieth pin 860.

[0240] The first terminal 983a of the twenty-seventh resistor 983 is electrically connected to the connection link between the collector 981b of the second transistor 981 and the sixtieth pin 860. The second terminal 983b of the twenty-seventh resistor 983 is grounded. The first plate 982a of the seventeenth capacitor 982 is electrically connected to the connection link between the collector 981b of the second transistor 981 and the sixtieth pin 860. The second plate 982b of the seventeenth capacitor 982 is electrically connected to the connection link between the second terminal 983b of the twenty-seventh resistor 983 and ground.

[0241] The first terminal 984a of the twenty-eighth resistor 984 is electrically connected to the first power supply 730, and the second terminal 984b of the twenty-eighth resistor 984 is electrically connected to the first terminal 985a of the twenty-ninth resistor 985. The emitter 981c of the second transistor 981 is electrically connected to the connection link between the first power supply 730 and the first terminal 984a of the twenty-eighth resistor 984. The base 981a of the second transistor 981 is electrically connected to the connection link between the second terminal 984b of the twenty-eighth resistor 984 and the first terminal 985a of the twenty-ninth resistor 985. The second terminal 985b of the twenty-ninth resistor 985 is electrically connected to pin 11 811 via the KEY EXIT signal line.

[0242] Pin 2 (802) is the ARMP signal pin. Pin 8 (808) is the ADO signal pin. Pin 9 (809) is the AD1 signal pin. Pin 11 (811) is the KEY-EXIT signal pin. Pin 14 (814) is the SCL signal pin. Pin 15 (815) is the SDA signal pin. Pin 16 (816) is the LED0 signal pin. Pin 17 (817) is the LED1 signal pin. Pin 20 (820) is the LCD CS signal pin. Pin 21 (821) is the SPI1 SCK signal pin. Pin 22 (822) is the LCD SA0 signal pin. Pin 23 (823) is the LCD SDAT signal pin. Pin 24 (824) is the KEY-RIGHT signal pin. Pin 25 (825) is the KEY-ADD signal pin. Pin 26 (826) is the AD2 signal pin. Pin 27 (827) is the AD3 signal pin. Pin 28 (828) is the IN0 signal pin. Pin 29 (829) is the IN1 signal pin. Pin 33 (833) is the WCLK signal pin. Pin 34 (834) is the BCLK signal pin. Pin 37 (837) is the MCLK signal pin. Pin 38 (838) is the LCD ON signal pin. Pin 39 (839) is the OUT EN signal pin. Pin 40 (840) is the LED4 signal pin. Pin 41 (841) is the LCD RES signal pin. Pin 42 (842) is the LED2 signal pin. Pin 43 (843) is the LED3 signal pin. Pin 46 (846) is the SWDIO signal pin. Pin 49 (849) is the SWCLK signal pin. Pin 50 (850) is the SPI3 NSS signal pin. Pin 51 (851) is the SPI3 SCK signal pin. Pin 52 (852) is the SPI3 MISO signal pin. Pin 53 (853) is the SPI3 MOSI signal pin. Pin 54 (854) is a spare pin and is unused. Pin 56 (856) is the MOTOPWM signal pin. Pin 57 (857) is the MOTO ON signal pin. Pin 58 (858) is the UART1 TX signal pin. Pin 59 is the UART1 RX signal pin. Pin 61 (861) is the FSC-CNN signal pin. Pin 62 (862) is the DETE0 signal pin.

[0243] like Figure 20 As shown, the first pin 994a of the external test interface 994 is connected to the first power supply 730. The second pin 994b of the external test interface 994 is the SWDIO signal pin, which is connected to the forty-sixth pin 846. The third pin 994c of the external test interface 994 is the SWCLK signal pin, which is connected to the forty-ninth pin 849. The fourth pin 994d of the external test interface 994 is grounded.

[0244] An environmental sensor is integrated on the circuit board, including a barometric pressure sensor (not shown in the figure). The environmental sensor detects environmental data in real time when the piston generator is working, and automatically corrects the operation by calculating the impact of the environmental data on the sound pressure of the piston generator.

[0245] The formula for calculating sound pressure P is shown in Formula 10.

[0246] Formula 10.

[0247] in, It is a constant with a value of 1.402. This is the ambient air pressure, measured in Pa. s is the working surface area of ​​piston 530, measured in square meters. V is the amplitude of piston 530's motion, measured in meters. V is the volume of the closed cavity 540, measured in square meters.

[0248] Since P in Formula 10 is a follower It changes with the changes, the norm We use standard atmospheric pressure (1×10⁻¹⁰ Pa), but standard atmospheric pressure is not accurate. We should replace the standard atmospheric pressure with the actual atmospheric pressure. For example, in City A (altitude 3600 meters), a high-altitude area, the sound pressure level is about 3 dB lower than in a typical plain area. This requires correction for atmospheric pressure variations to meet the specified level requirements. Since a barometric pressure sensor measures atmospheric pressure, we should use the value measured by the barometric pressure sensor as the ambient air pressure and substitute it into Formula 1. .

[0249] In this embodiment, through the design of the microcontroller and circuit integrated on the circuit board, the microcontroller U46 controls the rotation of the motor 40 through the pulse width modulation (PWM) interface, and detects the speed by using FG output through phase shifting, thereby achieving adjustable speed.

[0250] like Figure 12 As shown, in one embodiment of this application, the outer casing 10 includes a first casing 110 and a second casing 120 that are interlocked and fixedly connected. The battery compartment 721 is disposed near the second casing 120. The outer casing 10 is also provided with a USB interface 130.

[0251] The multi-frequency adjustable piston sound generator also includes multiple buttons 111 and a display screen 112.

[0252] Multiple buttons 111 are embedded in the first housing 110. A display screen 112 is embedded in the first housing 110.

[0253] Specifically, the display screen 112 can directly display the corrected sound pressure level, and it can also display environmental data. Therefore, users only need to carry a piston generator to complete the corresponding work, without needing to carry other equipment such as barometers, thermometers, or hygrometers, nor do they need to manually calculate correction values.

[0254] Specifically, such as Figure 11 As shown, the multiple buttons 111 include a plus button 111a, a minus button 111b, a start button 111c, and an end button 111d.

[0255] The operation process of the piston generator in this embodiment is as follows: For example, if the nominal sound pressure level of the piston generator is 124dB, environmental data is detected by an environmental sensor to assess the environmental impact. The piston generator uses a microcontroller to calculate and automatically correct the obtained sound pressure level to 124.04dB. The display screen 112 directly displays 124.04dB, and the user can directly use the corrected data, i.e., 124.04dB, for subsequent operations. Simultaneously, the piston generator directly displays environmental data and can generate usage records, allowing users to search for environmental data within these records.

[0256] In addition, a Bluetooth chip (not shown in the figure) or a WIFI chip (not shown in the figure) can be integrated on the circuit board to remotely upload the detection data to a remote server or mobile terminal.

Claims

1. A multi-frequency point tunable piston exciter, characterized in that, The multi-frequency adjustable piston sound generator comprises: a shell, which is internally hollow and has a top opening; a closed shell, the bottom of which is embedded in the top opening of the shell; a motor, which is arranged in the interior of the shell; a sound generating device, which is arranged in the interior of the closed shell and comprises a cam shell, the interior of which is provided with a cam mechanism, and a closed cavity is formed between the cam shell and the closed shell; the motor and the cam mechanism are fixedly connected, and sound pressure is generated in the closed cavity when the motor drives the cam mechanism to move; the rotating speed of the motor is adjustable; an adjusting member, which is clamped with the closed shell and is arranged to be freely rotatable relative to the closed shell; the adjusting member is provided with an adjusting member through hole, and the closed shell is provided with a plurality of closed shell through holes of different sizes; when the rotating speed of the motor is at different values, the adjusting member is rotated to align the closed shell through hole of different sizes with the adjusting member through hole; According to the changes to adjust and , so as to design different groups ( , , ), form different size of closed shell through hole, so as to adapt to different ; the length of the closed shell through hole, the radius of the closed shell through hole, the angular frequency of the cam.

2. The multi-frequency point tunable piston exciter according to claim 1, wherein, the outer ring wall of the closed shell is provided with a ring-shaped groove, and the adjusting member is clamped in the ring-shaped groove.

3. The multi-frequency point tunable piston exciter of claim 2, wherein, The ring-shaped groove is provided with a plurality of closed shell through holes of different sizes.

4. The multi-frequency point tunable piston exciter of claim 1, wherein, Further comprising: a connecting mechanism, which is arranged in the interior of the shell and is fixedly connected to the inner wall of the shell; the bottom of the closed shell and the top of the connecting mechanism are fixedly connected, the motor and the bottom of the connecting mechanism are fixedly connected, and the cam shell and the connecting mechanism are fixedly connected.

5. The multi-frequency point tunable piston exciter of claim 4, wherein, The connecting mechanism comprises: a connecting seat, which comprises a connecting sheet and a connecting boss, the connecting boss being arranged at the top of the connecting sheet and being fixedly connected with the connecting sheet; at least two connecting members, which are respectively arranged on both sides of the connecting sheet, each of which is fixedly connected with the connecting sheet and the inner wall of the shell.

6. The multi-frequency point tunable piston exciter of claim 5, wherein, The bottom of the closed shell is provided with a closed shell bottom opening part, which is threadedly connected with the connecting seat.

7. The multi-frequency point tunable piston exciter of claim 6, wherein, The top of the cam shell is provided with a cam shell top through hole.

8. The multi-frequency point tunable piston exciter of claim 7, wherein, The sound generating device further comprises: a sound cover, which is arranged outside the cam shell, is arranged between the closed shell and the cam shell, and is fixedly connected with the connecting mechanism; the sound cover is a cylindrical shell with an internally hollow, top closed end and a bottom open end, the top closed end is provided with a sound cover top through hole, and the sound cover top through hole is in communication with the cam shell top through hole.

9. The multi-frequency point tunable piston exciter of claim 8, wherein, The bottom open end forms an annular end face composed of the shell wall thickness; a plurality of limiting columns are arranged on the annular end face and are spaced along the axial direction, the top surface of each limiting column is fixedly connected with the annular end face, and the bottom surface of each limiting column is fixedly connected with the top surface of the connecting boss.

10. The multi-frequency point tunable piston exciter of claim 9, wherein, The limiting column has a height, so that a gap is generated between the annular end face of the sound cover and the top surface of the connecting boss. The cavity formed inside the cam housing is a cam housing cavity, the cavity between the closed housing and the cam housing is an intermediate cavity, the cam housing cavity and the intermediate cavity are communicated through the gap, and the cam housing cavity, the gap and the intermediate cavity jointly constitute the closed cavity.

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