A piston sounder

Abstract

The invention discloses a piston sounder, which belongs to the field of calibration equipment. The invention comprises a shell and a piston base installed in the shell, wherein a coupling cavity is provided in the shell, a cam is installed in the piston base, a piston for making sound by continuous reciprocating motion is installed on the piston base, a piston magnet is installed on the side of the piston facing the coupling cavity, and a clamping magnet for pressing the piston magnet toward the cam is also installed in the coupling cavity; since the clamping magnet will not contact with the piston magnet when pressing the piston magnet, friction will not be generated, and deformation will not occur, thus noise will not be generated, so that the calibration accuracy is higher, and the problem that in the prior art, the piston sounder realizes the resetting of the piston by a spring clamping structure, which will generate certain noise and further cause the distortion of the test structure is solved.

Description

Technical Field

[0001] The invention relates to a calibration device, in particular to a piston sounder. Background Art

[0002] Microphones are important energy conversion devices that convert sound signals into electrical signals. They are widely used in vocal music, communications, medical equipment and other fields. Usually, microphones need to be tested and calibrated for technical indicators such as sound pressure sensitivity, frequency response, and impedance before leaving the factory to ensure that the microphone output signal is accurate and effective.

[0003] In order to accurately measure and calibrate the sound pressure of the microphone, the sound calibrator came into being. The piston sounder is a very important microphone sound pressure sensitivity calibration device. It drives the piston to make sinusoidal vibrations of a given frequency and amplitude through an excitation device, forming a sound field in the cavity that can determine the sound pressure. The sound pressure sensitivity of the microphone can be determined by comparing it with the open circuit voltage of the microphone. At present, most piston sounders on the market use a micro motor to drive the cam to rotate, and the cam drives the piston to move back and forth in the cavity, thereby changing the pressure of the cavity and generating sound. During calibration, the front end of the microphone is inserted into the coupling cavity. In order to reduce the influence of external environmental fluctuations (such as air pressure and temperature changes) on the calibration results of the microphone, the coupling cavity needs to be connected to the external environment to balance the static pressure between the two. Generally, the cam rotates to drive the piston to move back and forth in the piston cavity, thereby changing the pressure of the coupling cavity. Since the surface area, piston stroke and cavity volume (when the piston is in the middle position) of the piston remain unchanged, a stable sound pressure is generated; and an air pressure sensor is set in the piston sounder. While measuring and displaying the atmospheric pressure, it automatically corrects and digitally displays the sound pressure level generated by the piston generator.

[0004] The existing piston sounder uses a spring-compressed structure to reset the piston. Since the spring itself will continue to deform while driving the piston to move, and a certain amount of friction will be generated between the spring and the piston, a certain amount of noise will be generated, which will cause distortion of the test structure. In addition, since the spring will continue to age during the process of continuous deformation, the service life of the piston sounder is relatively short.

[0005] For example, a "piston reset structure of a piston generator" disclosed in Chinese patent documents, with the publication number CN210298051U, includes: a base, on which a cam cavity for placing a cam is provided; two piston cavities are provided on the side wall; a cam, which is connected to an external motor and installed in the cam cavity; a piston, one end of which is connected to the contour surface of the cam and the other end of which is provided with a mounting cavity; two pistons are slidably connected in the two piston cavities; an elastic element for making the piston move along the contour surface of the cam is arranged on each side of the base, and the two ends of the elastic element are respectively connected to the mounting cavities of the two pistons. The two pistons are connected by two elastic elements distributed on both sides of the base, so that the pistons are subjected to balanced force during the resetting process, the drift between the contact points of the spring and the piston is reduced, and the total distortion of the piston sounder during operation is reduced; however, the shortcoming of this patent is that it uses a spring to reset the piston. Since the spring itself will continue to deform while driving the piston to move, and a certain amount of friction will be generated between the spring and the piston, a certain amount of noise will be generated, which will lead to distortion of the test structure. In addition, since the spring will continue to age during the continuous deformation process, the service life of the piston sounder is relatively short. Summary of the invention

[0006] The present invention aims to overcome the problem in the prior art that a piston sounder achieves the resetting of the piston through a spring-compressed structure. Since the spring itself will continue to deform while driving the piston to move, and a certain friction will be generated between the spring and the piston, a certain noise will be generated, which will lead to distortion of the test structure. A piston sounder is provided with better calibration accuracy and longer service life.

[0007] In order to achieve the above object, the present invention adopts the following technical solutions:

[0008] The present invention provides a piston sounder, comprising a shell and a piston base installed in the shell, wherein a coupling cavity is provided in the shell, a cam cavity is provided in the piston base, a piston for producing sound by continuous reciprocating motion is installed on the piston base, the outer side of the piston faces the coupling cavity, the inner side of the piston faces the cam cavity, a cam for driving the piston to reciprocate is installed in the cam cavity, a piston magnet is installed on the side of the piston facing the coupling cavity, and a tightening magnet for tightening the piston magnet toward the cam direction is also installed in the coupling cavity.

[0009] The clamping magnet clamps the piston magnet onto the cam through the repulsive force between the magnets. Since the radius of curvature of the contact point between the cam and the piston changes continuously during the rotation of the cam, the piston will continuously reciprocate in the direction of the cam, thereby generating sound pressure in the coupling cavity. Since the clamping magnet does not come into contact with the piston magnet when clamping the piston magnet, no friction will be generated and no deformation will occur, so no noise will be generated, thereby improving the calibration accuracy. In addition, the magnetism of the magnet is less likely to fade than the elasticity of the spring, thereby extending the service life of the device.

[0010] Preferably, an adjusting cover base for adjusting the volume of the coupling chamber is installed on the piston base, and an adjusting cover is installed on the adjusting cover base, and the adjusting cover is threadedly connected to the adjusting cover base; by screwing the adjusting cover on the adjusting cover base, the adjusting cover can be moved axially relative to the adjusting cover base, and when the adjusting cover is away from the adjusting cover base, the volume of the coupling chamber decreases, and vice versa, the volume of the coupling chamber increases. By adjusting the volume of the coupling chamber, the sound pressure level of the sound signal generated by the sound generator can be changed. Once the sound pressure in the coupling chamber does not meet the expectations due to processing accuracy problems, it can be adjusted through the adjusting cover. In addition, by adjusting the adjusting cover, it can also be suitable for calibration of a variety of different sound pressure levels.

[0011] Preferably, the adjusting cover base is provided with an adjusting cover rib covering the adjusting outer edge, and a first sealing ring is provided between the adjusting cover rib and the adjusting cover; the space between the adjusting cover and the adjusting cover base can be separated by the adjusting cover rib and the first sealing ring, thereby ensuring that the coupling cavity will not release pressure from the gap between the two.

[0012] Preferably, the housing is provided with a mounting opening, and the adjustment cover is provided with a wrench slot in the direction toward the mounting opening; the mounting opening is used for the microphone to be calibrated, and when the position of the adjustment cover needs to be adjusted, the wrench can be adjusted by simply inserting it into the mounting opening.

[0013] Preferably, the adjusting cover base is further provided with a magnet mounting seat located outside the piston, and the tightening magnet is mounted on the magnet mounting seat; the magnet mounting seat enables the magnet to be reliably mounted and is easy to disassemble and replace.

[0014] Preferably, the piston base is also connected to a motor mounting seat, and a motor for driving the cam to rotate is installed in the motor mounting seat.

[0015] Preferably, a motor connecting seat is also installed between the motor mounting seat and the piston base, and the motor connecting seat and the motor mounting seat are provided with abutting surfaces that abut each other, and the abutting surfaces are conical surfaces; the abutting surfaces can prevent the radial position of the motor from changing due to vibration during operation, thereby affecting the position of the cam.

[0016] Preferably, the motor mounting seat, the motor connecting seat and the piston are fixedly connected by three circumferentially evenly distributed motor mounting screws; the three circumferentially evenly distributed screws can better determine the center position of the motor and ensure the accuracy of its installation position in the radial direction.

[0017] Preferably, the motor mounting seat is further provided with an air port connecting the cam cavity and the outside of the motor mounting seat, and the air port can ensure the pressure balance of the cam cavity during the movement of the piston, thereby preventing the movement of the piston from being affected by the pressure.

[0018] Therefore, the present invention has the following beneficial effects: (1) during the piston resetting process, no contact and friction will occur, thereby reducing the generation of noise and avoiding distortion in the calibration process; (2) the device has a longer service life; (3) the coupling chamber volume can be adjusted to cope with the situation where the coupling chamber volume does not conform to the design due to insufficient processing accuracy; (4) the motor positioning is more accurate, avoiding the situation where the piston movement does not conform to the design due to insufficient cam position accuracy. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 It is a schematic diagram of a cross-sectional structure in a front view state of the present invention.

[0020] Figure 2 It is a schematic diagram of a cross-sectional structure of the present invention in a side view state.

[0021] In the figure: 1, housing 2, piston base 3, coupling chamber 4, cam chamber 5, piston 6, protruding head 7, cam 8, piston magnet 9, tightening magnet 10, adjusting cover base 11, adjusting cover 12, adjusting cover rib 13, first sealing ring 14, second sealing ring 15, wrench groove 16, magnet mounting seat 17, motor mounting seat 18, motor 19, motor interface 20, motor connecting seat 21, first abutting surface 22, second abutting surface 23, motor mounting screw 24, air port. DETAILED DESCRIPTION

[0022] In order to make the purpose, technical scheme and advantages of the technical solution embodiment of the present invention clearer, the technical solution of the embodiment of the present invention is clearly explained and illustrated in conjunction with the accompanying drawings below, but the following embodiments are only preferred embodiments of the present invention, rather than all embodiments. Based on the embodiments in the implementation mode, other embodiments obtained by those skilled in the art without making creative work are all within the scope of protection of the present invention.

[0023] Embodiments of the present invention are described in detail below, examples of which are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present solution, and cannot be interpreted as limiting the solution of the present invention.

[0024] These and other aspects of the embodiments of the present invention will become clear with reference to the following description and drawings. In these descriptions and drawings, some specific implementations of the embodiments of the present invention are specifically disclosed to represent some ways of implementing the principles of the embodiments of the present invention, but it should be understood that the scope of the embodiments of the present invention is not limited thereto. On the contrary, the embodiments of the present invention include all changes, modifications and equivalents that fall within the spirit and connotation of the appended claims.

[0025] like Figure 1-2 In the embodiment shown, a piston sounder comprises a shell 1 and a piston base 2 installed in the shell, wherein a coupling chamber 3 is provided in the shell, a cam chamber 4 is provided in the piston base, a piston 5 for making sound by continuous reciprocating motion is installed on the piston base, the outer side of the piston faces the coupling chamber, the inner side of the piston faces the cam chamber, a convex head 6 for point contact with the cam is provided on the inner side of the piston, a cam 7 for driving the piston to reciprocate is installed in the cam chamber, a piston magnet 8 is installed on the side of the piston facing the coupling chamber, and a tightening magnet 9 for tightening the piston magnet toward the cam direction is also installed in the coupling chamber; an adjusting cover base 10 for adjusting the volume of the coupling chamber is installed on the piston base, an adjusting cover 11 is installed on the adjusting cover base, and the adjusting cover is threadedly connected to the adjusting cover base; an adjusting cover rib 12 covering the adjusting outer edge is provided on the adjusting cover base, a first sealing ring 13 is provided between the adjusting cover rib and the adjusting cover, and the adjusting cover base is connected to the piston base A second sealing ring 14 is provided between the seats; the adjusting cover is provided with a wrench groove 15 in the direction toward the mounting port; the adjusting cover base is also provided with a magnet mounting seat 16 located on the outside of the piston, and the tightening magnet is installed on the magnet mounting seat; the piston base is also connected to a motor mounting seat 17, in which a motor 18 for driving the cam to rotate is installed, and a motor interface 19 is provided on the motor; a motor connecting seat 20 is also installed between the motor mounting seat and the piston base, and abutment surfaces abutting each other are provided on the motor connecting seat and the motor mounting seat, and the abutment surfaces are conical surfaces; the abutment surfaces include a first abutment surface 21 and a second abutment surface 22 with different inclination angles, wherein the inclination angle of the first abutment surface is 30°, and the inclination angle of the second abutment surface is 45°; the motor mounting seat, the motor connecting seat, and the piston are fixedly connected by three circumferentially evenly distributed motor mounting screws 23; the motor mounting seat is also provided with an air port 24 connecting the cam cavity and the outside of the motor mounting seat.

[0026] There are two pistons facing each other. The cam is provided with a raised position and a recessed position. When the contact point between the piston and the cam moves from the raised position to the recessed position, the piston moves toward the cam. When the contact point between the piston and the cam moves from the recessed position to the raised position, the piston moves away from the cam.

Claims

1. A piston sounder, characterized in that: It comprises an outer shell and a piston base installed in the outer shell, wherein a coupling cavity is provided in the outer shell, a cam cavity is provided in the piston base, a piston for producing sound by continuous reciprocating motion is installed on the piston base, the outer side of the piston faces the coupling cavity, the inner side of the piston faces the cam cavity, a cam for driving the piston to reciprocate is installed in the cam cavity, a piston magnet is installed on the side of the piston facing the coupling cavity, a tightening magnet for tightening the piston magnet toward the cam is also installed in the coupling cavity; a convex head for point contact with the cam is provided on the inner side of the piston, the number of the pistons is two and they are directly opposite to each other, and a raised position and a recessed position are provided on the cam.

2. A piston sounder according to claim 1, characterized in that: An adjusting cover base for adjusting the volume of the coupling cavity is installed on the piston base, an adjusting cover is installed on the adjusting cover base, and the adjusting cover is threadedly connected to the adjusting cover base.

3. A piston sounder according to claim 2, characterized in that: The adjusting cover base is provided with an adjusting cover rib covering the adjusting outer edge, and a first sealing ring is provided between the adjusting cover rib and the adjusting cover.

4. A piston sounder according to claim 2, characterized in that: The shell is provided with a mounting opening, and the adjustment cover is provided with a wrench groove in a direction toward the mounting opening.

5. A piston sounder according to claim 2, characterized in that: The adjusting cover base is also provided with a magnet mounting seat located outside the piston, and the pressing magnet is mounted on the magnet mounting seat.

6. A piston sounder according to any one of claims 1 to 5, characterized in that: The piston base is also connected to a motor mounting seat, in which a motor for driving the cam to rotate is installed.

7. A piston sounder according to claim 6, characterized in that: A motor connecting seat is also installed between the motor mounting seat and the piston base. The motor connecting seat and the motor mounting seat are provided with abutting surfaces abutting against each other, and the abutting surfaces are conical surfaces.

8. A piston sounder according to claim 7, characterized in that: The motor mounting seat, the motor connecting seat and the piston are fixedly connected by three circumferentially evenly spaced motor mounting screws.

9. A piston sounder according to claim 6, characterized in that: The motor mounting seat is also provided with an air port communicating with the cam cavity and the outside of the motor mounting seat.

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