Active frequency modulation non-piezoelectric acoustic generator

Abstract

The invention discloses a non-piezoelectric acoustic generator with an active frequency modulation function, and relates to the technical field of acoustic generators. A traditional piezoelectric acoustic generator cannot meet enough spatial scale and vibration displacement required by high-intensity noise due to the working principle of the traditional piezoelectric acoustic generator, and the traditional piezoelectric acoustic generator can meet the increasing requirements of multiple fields of ocean exploration, biological protection, national defense equipment and the like on the acoustic generator. Hydrodynamic noise generated by swinging of blades replaces a loudspeaker in a piezoelectric acoustic generator, a main motor drives a main body of a rotor, namely a rotating paddle, a transmission shaft and a paddle disc to rotate, a flow field is preliminarily disturbed, and a certain vortex is generated; the auxiliary motor drives the transmission shaft and the blades to swing according to a certain rule and further swing greatly, a large number of vortexes are generated, and then hydrodynamic noise with enough strength is generated; meanwhile, the rotation and swing frequency and swing amplitude of the blades are adjusted through the control box, and the noise spectrum law of the target characteristics is directionally modulated. The acoustic generator is applicable to special environments.

Description

Technical Field

[0001] The invention relates to the technical field of acoustic generators, and in particular to the research and design of an actively frequency modulated acoustic generator. Background Art

[0002] An acoustic generator is a device that generates sounds of different frequencies, amplitudes, and waveforms by adjusting parameters. Currently, mainstream acoustic generators mainly use the piezoelectric principle to convert electrical energy and acoustic energy into each other. However, due to external energy limitations, extreme working environment requirements, and limited frequency range, the study of a non-piezoelectric, actively frequency-adjustable acoustic generator is of great significance for research in many fields, including marine life, acoustic geological detection, and national defense equipment. Summary of the invention

[0003] The purpose of the present invention is to make up for the defects and shortcomings of the existing acoustic generator under the piezoelectric working principle, so as to provide a new acoustic generator that can be used in special environments.

[0004] To achieve the above object, the present invention provides the following technical solutions:

[0005] The present invention provides an active frequency-modulated non-piezoelectric acoustic generator, comprising a propeller disc, four propeller blades, four propeller blade transmission shafts, a driving device and a transmission mechanism;

[0006] The driving device comprises a main motor and an auxiliary motor;

[0007] The four blades are evenly arranged around the propeller disc and fixed on the propeller disc through four blade transmission shafts;

[0008] The main motor is used to drive the propeller disc to rotate through the transmission mechanism, thereby driving the four propeller drive shafts and the four propeller blades to revolve as the background of the watershed disturbance;

[0009] The auxiliary motor transmits power to the four blade drive shafts through the transmission mechanism, thereby driving the four blades to rotate. On the basis of the revolution disturbing the fluid to form a vortex and emit flow noise, the noise is autonomously modulated through rotation with different frequencies and amplitudes.

[0010] Further, there is a preferred embodiment, the transmission mechanism comprises a main shaft, an auxiliary motor connecting shaft, a first spur gear, a second spur gear, a spur bevel gear set, a sleeve, a first deep groove ball bearing and a second deep groove ball bearing;

[0011] The spur bevel gear set comprises a first spur bevel gear, a second spur bevel gear, a third spur bevel gear, a fourth spur bevel gear and a fifth spur bevel gear;

[0012] The first spur bevel gear is meshed with the second to fifth spur bevel gears, and the second to fifth spur bevel gears are connected to four blade transmission shafts respectively;

[0013] The upstream of the propeller disc is connected to the main motor, and the propeller disc and the main motor are connected through a main shaft;

[0014] The first spur gear is fixed to the main shaft downstream of the impeller disc through a sleeve and a first deep groove ball bearing;

[0015] The first spur bevel gear is fixed to the main shaft downstream of the first spur cylindrical gear through a second deep groove ball bearing, and the sleeve is connected to the first spur bevel gear;

[0016] The auxiliary motor is connected to the auxiliary motor upstream of the auxiliary motor connecting shaft, and the second spur gear is fixed to the auxiliary motor connecting shaft downstream, and the first spur gear and the second spur gear are meshed with each other.

[0017] Furthermore, in a preferred embodiment, the main motor and the auxiliary motor are arranged in parallel and can be driven separately through a sleeve.

[0018] Furthermore, in another preferred embodiment, the propeller disc and the main shaft are rigidly connected;

[0019] The first deep groove ball bearing and the second deep groove ball bearing are connected to the main shaft by flat key connection.

[0020] Furthermore, in a preferred embodiment, the first spur gear and the sleeve are connected by a flat key;

[0021] The auxiliary motor connecting shaft and the second spur gear are connected by a flat key.

[0022] Furthermore, in a preferred embodiment, the spur bevel gear and the blade transmission shaft are connected by a wedge key;

[0023] The sleeve is connected to the first spur bevel gear by a wedge key.

[0024] Furthermore, in a preferred embodiment, the blade transmission shaft is rigidly connected to the blade.

[0025] Furthermore, in a preferred embodiment, the paddle disc is a flat cylindrical structure.

[0026] Furthermore, there is a preferred embodiment in which the blades are thin iron sheet structures of a round fan.

[0027] The present invention also provides a method for using any one of the above-mentioned non-piezoelectric acoustic generators with active frequency modulation, the method comprising:

[0028] The revolution frequency of the propeller disc and the blades is set to achieve large disturbances in the watershed;

[0029] The rotation frequency and amplitude of the four blades are set to directionally modulate the noise.

[0030] The beneficial effects of the present invention are:

[0031] 1. The present invention is based on the relevant knowledge and research content of fluid dynamics, acoustics and vibration, and refers to the noise problem of mechanical flow-induced vibration of blades. The reverse development is to achieve sound generation through the autonomous regular vibration of blades, and to achieve active frequency modulation by adjusting the vibration frequency and amplitude. By abandoning the piezoelectric transducer, the new acoustic generator described in the present invention can obtain excellent anti-interference ability, and has independent operation, simple structure and low cost.

[0032] 2. The acoustic generator provided by the present invention replaces the speaker in the piezoelectric acoustic generator with the hydrodynamic noise generated by the swing of the blades. The main motor drives the main body of the rotor, namely the propeller, the transmission shaft and the impeller disk, to rotate, thereby preliminarily disturbing the flow field and generating certain vortices. The auxiliary motor drives the transmission shaft and the blades to swing in a certain pattern, and further swings in a large amplitude to generate a large number of vortices, thereby generating hydrodynamic noise of sufficient intensity. At the same time, the rotation and swinging frequency and the swinging amplitude of the blades are adjusted through the control box to directionally modulate the noise spectrum law of the target characteristics.

[0033] 3. The present invention realizes large-scale disturbance of the watershed through the revolution of the propeller disk and the blades, and directionally modulates the noise by adjusting the rotation frequency and amplitude of the four blades. Compared with the traditional piezoelectric acoustic generator, it not only improves its anti-interference performance, but also meets the sufficiently large spatial scale and vibration displacement required for high-intensity noise.

[0034] 4. The present invention generates sound only through a mechanical structure on the basis of meeting the spatial displacement scale of high-intensity noise, which simplifies the structure, saves costs and also improves its working ability in some special environments.

[0035] The present invention is applicable to the field of acoustic generators under external energy limitation and extreme working environment requirements. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] In order to more clearly illustrate the specific implementation methods of the present invention or the technical solutions in the prior art, the drawings required for use in the specific implementation methods or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some implementation methods of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0037] Figure 1It is a schematic diagram of a non-piezoelectric acoustic generator with active frequency modulation according to the present invention;

[0038] Figure 2 It is a schematic diagram of the appearance structure of the acoustic generator body of the present invention;

[0039] Figure 3 It is a schematic diagram of the transmission mechanism inside the main body of the acoustic generator of the present invention;

[0040] Figure 4 It is a left side view of the transmission mechanism inside the main body of the acoustic generator of the present invention;

[0041] Figure 5 It is a schematic diagram of the calculation domain and some boundary conditions of the model described in the present invention;

[0042] Figure 6 It is a diagram of the noise propagation law along the axis of the three working conditions described in the present invention;

[0043] Figure 7 It is a spectrum regularity diagram of the sound pressure level at the far-field critical point of the three working conditions described in the present invention.

[0044] Among them, 1 is the main shaft, 2 is the auxiliary motor connecting shaft, 3 is the first blade transmission shaft, 4 is the second blade transmission shaft, 5 is the third blade transmission shaft, 6 is the fourth blade transmission shaft, 7 is the first spur gear, 8 is the second spur gear, 9 is the first spur bevel gear, 10 is the second spur bevel gear, 11 is the third spur bevel gear, 12 is the fourth spur bevel gear, 13 is the fifth spur bevel gear, 14 is the sleeve, 15 is the first deep groove ball bearing, and 16 is the second deep groove ball bearing. DETAILED DESCRIPTION

[0045] The specific embodiments of the present invention are further described in detail below in conjunction with the accompanying drawings. The following embodiments will help those skilled in the art to further understand the present invention, but do not limit the present invention in any form. It should be noted that, for those of ordinary skill in the art, several changes and improvements can be made without departing from the concept of the present invention, which all belong to the protection scope of the present invention.

[0046] Implementation method 1, see Figure 1 and Figure 2 This embodiment describes an actively frequency modulated non-piezoelectric acoustic generator, which is used to compensate for the defects and shortcomings of existing acoustic generators that adopt the piezoelectric working principle and cannot be used normally due to external energy limitations, extreme working environment requirements, limited frequency range and other issues.

[0047] An actively frequency modulated non-piezoelectric acoustic generator comprises a propeller disc, four propeller blades, four propeller blade transmission shafts, a driving device and a transmission mechanism;

[0048] The driving device comprises a main motor and an auxiliary motor;

[0049] The four blades are evenly arranged around the propeller disc and fixed on the propeller disc through four blade transmission shafts;

[0050] The main motor is used to drive the propeller disc to rotate through the transmission mechanism, thereby driving the four propeller drive shafts and the four propeller blades to revolve as the background of the watershed disturbance;

[0051] The auxiliary motor transmits power to the four blade drive shafts through the transmission mechanism, thereby driving the four blades to rotate. On the basis of the revolution disturbing the fluid to form a vortex and emit flow noise, the noise is autonomously modulated through rotation with different frequencies and amplitudes.

[0052] In practical application, if Figure 2 As shown, the propeller disc is a flat cylindrical structure, which mainly plays the role of support and transmission; the blade is a thin iron sheet structure shaped like a fan, which serves as the main body of the acoustic generator and the main sound-generating device; the four blade drive shafts are cast iron cylindrical structures, which mainly play the role of connection and transmission; the four blades are evenly arranged around the propeller disc and fixed to the propeller disc through four blade drive shafts.

[0053] like Figure 1 As shown, the acoustic generator also requires at least two motors as driving devices. That is, the main motor and the auxiliary motor, where the main motor is used as the power device for the acoustic generator to revolve, so that the main motor drives the impeller to rotate through the transmission mechanism, thereby driving the four blade drive shafts and the four blades to revolve, as the background of the flow disturbance. The auxiliary motor transmits power to the four blade drive shafts through the transmission mechanism, thereby driving the four blades to rotate, and realizing the autonomous frequency modulation of the noise through the rotation of different frequencies and amplitudes on the basis of the vortex formed by the revolving disturbed fluid to emit flow noise. At the same time, the rotation and swing frequency and swing amplitude of the blades are adjusted through the control box to directionally modulate the noise spectrum law of the target characteristics.

[0054] The acoustic generator described in this embodiment is based on the relevant knowledge and research content of fluid dynamics, acoustics and vibration, and refers to the noise problem caused by the mechanical flow-induced vibration of the blade. It is developed in reverse, that is, sound is generated by the autonomous and regular vibration of the blade, and active frequency modulation is achieved by adjusting the vibration frequency and amplitude.

[0055] Furthermore, the acoustic generator described in this embodiment realizes large-scale disturbance of the watershed through the revolution of the propeller disk and the blades, and directionally modulates the noise by adjusting the rotation frequency and amplitude of the four blades. Compared with the traditional piezoelectric acoustic generator, it not only improves its anti-interference performance, but also meets the sufficiently large spatial scale and vibration displacement required for high-intensity noise.

[0056] Implementation Method 2: See Figure 3 and Figure 4 This embodiment is described. This embodiment specifically describes the structure of an active frequency modulation non-piezoelectric acoustic generator described in the first embodiment.

[0057] The transmission mechanism includes a main shaft 1, an auxiliary motor connecting shaft 2, a first spur gear 7, a second spur gear 8, a spur bevel gear set, a sleeve 14, a first deep groove ball bearing 15 and a second deep groove ball bearing 16;

[0058] The spur bevel gear set comprises a first spur bevel gear 9, a second spur bevel gear 10, a third spur bevel gear 11, a fourth spur bevel gear 12 and a fifth spur bevel gear 13;

[0059] The first spur bevel gear 9 is meshed with the second to fifth spur bevel gears, and the second to fifth spur bevel gears are connected to four blade transmission shafts respectively;

[0060] The upstream of the propeller disc is connected to the main motor, and the propeller disc and the main motor are connected through a main shaft 1;

[0061] The first spur gear 7 is fixed on the main shaft 1 downstream of the impeller disc through a sleeve 14 and a first deep groove ball bearing 15;

[0062] The first spur bevel gear 9 is fixed to the main shaft 1 downstream of the first spur bevel gear 7 through a second deep groove ball bearing 16, and the sleeve 14 is connected to the first spur bevel gear 9;

[0063] The auxiliary motor is connected to the auxiliary motor upstream of the auxiliary motor connecting shaft 2 , and the second spur gear 8 is fixed to the auxiliary motor connecting shaft 2 downstream, and the first spur gear 7 and the second spur gear 8 are meshed with each other.

[0064] In practical application, if Figure 3 and Figure 4 As shown, the four blade transmission shafts include a first blade transmission shaft 3 , a second blade transmission shaft 4 , a third blade transmission shaft 5 and a fourth blade transmission shaft 6 .

[0065] The spur bevel gear set consists of five spur bevel gears, including a first spur bevel gear 9, a second spur bevel gear 10, a third spur bevel gear 11, a fourth spur bevel gear 12 and a fifth spur bevel gear 13; wherein the first spur bevel gear 9 is meshed with the second to fifth spur bevel gears, and the second to fifth spur bevel gears are respectively connected to the four blade transmission shafts with wedge keys to balance the radial force.

[0066] The main motor is located upstream of the propeller disc, and the propeller disc is connected to the main motor through the main shaft 1, and the main shaft 1 and the propeller disc are rigidly connected; the first spur gear 7 is fixed on the main shaft 1 downstream of the propeller disc, and the first spur gear 7 is fixed on the main shaft 1 downstream of the propeller disc through the sleeve 14 and the first deep groove ball bearing 15, and the first spur gear 7 and the sleeve 14 are connected by a flat key; the first spur bevel gear 9 is fixed on the main shaft 1 downstream of the first spur gear 7 through the second deep groove ball bearing 16, and the sleeve 14 is connected to the first spur bevel gear 9 by a wedge key; the auxiliary motor is connected to the auxiliary motor connecting shaft 2 upstream, and the second spur gear 8 is fixed downstream of the auxiliary motor connecting shaft 2, and the first spur gear 7 and the second spur gear 8 are meshed with each other. The main motor and the auxiliary motor are arranged in parallel, and the two can be driven separately through the sleeve 14.

[0067] Under the action of the main motor driving the propeller disc, the propeller disc drives the transmission shaft and the blades to revolve, which serves as the background of the disturbance in the watershed. In terms of transmission, the transmission shaft not only transmits the revolution of the propeller disc, but also transmits the rotation driven by the upstream auxiliary motor to drive the blades to rotate, that is, the auxiliary motor connects four transmission shafts through spur bevel gears, spur cylindrical gears and sleeves, which is the power device that generates the self-rotation noise of the blades and is also the main noise source of the acoustic generator. On the basis of the vortex generated by the revolution disturbance fluid to emit flow noise, the noise is autonomously modulated through self-rotation with different frequencies and amplitudes.

[0068] The acoustic generator provided in this embodiment generates sound only through a mechanical structure on the basis of meeting the spatial displacement scale of high-intensity noise. The hydrodynamic noise generated by the swing of the blades replaces the speaker in the piezoelectric acoustic generator. The main motor drives the main body of the rotor, namely the propeller, the transmission shaft and the propeller disk to rotate, thereby preliminarily disturbing the flow field and generating certain vortices. The auxiliary motor drives the transmission shaft and the blades to swing in a certain pattern, and further swings in a large amplitude to generate a large number of vortices, thereby generating hydrodynamic noise of sufficient intensity. At the same time, the rotation and swinging frequency and the swinging amplitude of the blades are adjusted through the control box to directionally modulate the noise spectrum law of the target characteristics.

[0069] Embodiment 3: This embodiment provides a method for using the non-piezoelectric acoustic generator with active frequency modulation described in the above embodiment, and the method comprises the following steps:

[0070] Step 1: Set the revolution frequency of the propeller disc and the blades to achieve a large disturbance in the watershed;

[0071] Step 2: Set the rotation frequency and amplitude of the four blades to directionally modulate the noise.

[0072] Implementation method 4: See Figures 5 to 7To explain this embodiment, this embodiment is to perform numerical simulation verification on an actively frequency modulated non-piezoelectric acoustic generator described in the above-mentioned embodiment. Taking into account the possibility of calculation, driving devices such as motors and other auxiliary components are ignored, and only the main components, namely the propeller disc, connecting shaft and blades, are numerically simulated.

[0073] by Figure 5 The boundary conditions in the calculation are as follows: 600rpm, blade pitch angle 15°, blade non-swinging condition; 600rpm, blade pitch angle 15°, blade swing frequency 2Hz; and 600rpm, blade pitch angle 40°, blade swing frequency 2Hz. Figure 6 The noise propagation law along the axis of the three working conditions shown in the figure and Figure 7 The sound pressure level spectrum at the far-field critical point of the three working conditions is shown in the figure. It can be clearly seen from the figure that the swing of the blade can generate noise of considerable intensity, and the swing frequency and amplitude have a certain influence on the noise sound pressure level, and the swing frequency has a relatively greater influence.

[0074] In summary, the acoustic generator provided in this embodiment can achieve large-scale disturbance of the watershed through the revolution of the propeller disk and the blades, and can directionally modulate the noise by adjusting the rotation frequency and amplitude of the four blades. Compared with the traditional piezoelectric acoustic generator, it not only improves its anti-interference performance, but also meets the sufficiently large spatial scale and vibration displacement required for high-intensity noise.

[0075] In the above description, specific details such as specific system structures and technologies are provided for the purpose of illustration rather than limitation, so as to provide a thorough understanding of the embodiments of the present application. However, it should be clear to those skilled in the art that the present application can also be implemented in other embodiments without these specific details. In other cases, detailed descriptions of well-known systems, devices, circuits, and methods are omitted, and the gears, sleeves, and bearings used in the present invention are all standard parts. This is to prevent unnecessary details from hindering the description of the present application.

[0076] It should be understood that when used in this specification and the appended claims, the term "comprising" indicates the presence of described features, integers, steps, operations, elements and / or components, but does not exclude the presence or addition of one or more other features, integers, steps, operations, elements, components and / or groups thereof.

[0077] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include at least one of the features. In the description of the present invention, the meaning of "plurality" is at least two, such as two, three, etc., unless otherwise clearly and specifically defined.

[0078] In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art can combine and combine different embodiments or examples described in this specification and the features of different embodiments or examples without contradiction.

[0079] The above description is only the implementation mode of the present invention and is not limited to the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent substitution, improvement, etc. made within the spirit and principle of the present invention shall be included in the scope of the claims of the present invention.

Claims

1. An actively frequency modulated non-piezoelectric acoustic generator, characterized in that: It includes a propeller disc, four propeller blades, four propeller blade transmission shafts, a driving device and a transmission mechanism; The driving device comprises a main motor and an auxiliary motor; The four blades are evenly arranged around the propeller disc and fixed on the propeller disc through four blade transmission shafts; The main motor is used to drive the propeller disc to rotate through the transmission mechanism, thereby driving the four propeller drive shafts and the four propeller blades to revolve; The auxiliary motor transmits power to the four propeller drive shafts through a transmission mechanism, thereby driving the four propeller blades to rotate.

2. The non-piezoelectric acoustic generator with active frequency modulation according to claim 1, characterized in that: The transmission mechanism comprises a main shaft (1), an auxiliary motor connecting shaft (2), a first spur gear (7), a second spur gear (8), a spur bevel gear set, a sleeve (14), a first deep groove ball bearing (15) and a second deep groove ball bearing (16); The spur bevel gear set comprises a first spur bevel gear (9), a second spur bevel gear (10), a third spur bevel gear (11), a fourth spur bevel gear (12) and a fifth spur bevel gear (13); The first spur bevel gear (9) is meshed with the second to fifth spur bevel gears, and the second to fifth spur bevel gears are connected to four blade transmission shafts respectively; The upstream of the impeller disc is connected to a main motor, and the impeller disc and the main motor are connected via a main shaft (1); The first spur gear (7) is fixed to the main shaft (1) downstream of the impeller disc via a sleeve (14) and a first deep groove ball bearing (15); The first spur bevel gear (9) is fixed to the main shaft (1) downstream of the first spur cylindrical gear (7) via a second deep groove ball bearing (16), and the sleeve (14) is connected to the first spur bevel gear (9); The auxiliary motor is connected to the auxiliary motor upstream of the auxiliary motor connecting shaft (2), and the second spur gear (8) is fixed downstream of the auxiliary motor connecting shaft (2), and the first spur gear (7) and the second spur gear (8) are meshed with each other.

3. The non-piezoelectric acoustic generator with active frequency modulation according to claim 2, characterized in that: The main motor and the auxiliary motor are arranged in parallel and can be driven separately through a sleeve (14).

4. The non-piezoelectric acoustic generator with active frequency modulation according to claim 2, characterized in that: The propeller disc is rigidly connected to the main shaft (1); The first deep groove ball bearing (15) and the second deep groove ball bearing (16) are connected to the main shaft (1) by means of a flat key connection.

5. The non-piezoelectric acoustic generator with active frequency modulation according to claim 2, characterized in that: The first spur gear (7) and the sleeve (14) are connected by a flat key; The auxiliary motor connecting shaft (2) and the second spur gear (8) are connected by a flat key.

6. The non-piezoelectric acoustic generator with active frequency modulation according to claim 2, characterized in that: The spur bevel gear and the propeller drive shaft are connected by a wedge key; The sleeve (14) is connected to the first spur bevel gear (9) by using a wedge key.

7. The non-piezoelectric acoustic generator with active frequency modulation according to claim 2, characterized in that: The propeller drive shaft is rigidly connected to the propeller blade.

8. The non-piezoelectric acoustic generator with active frequency modulation according to claim 1, characterized in that: The paddle disc is a flat cylindrical structure.

9. The non-piezoelectric acoustic generator with active frequency modulation according to claim 1, characterized in that: The blades are made of thin iron sheets like a round fan.

10. The method for using the non-piezoelectric acoustic generator with active frequency modulation according to any one of claims 1 to 9, characterized in that: The method is: The revolution frequency of the propeller disc and the blades is set to achieve large disturbances in the watershed; The rotation frequency and amplitude of the four blades are set to directionally modulate the noise.

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