Miniature loudspeaker

Abstract

The utility model relates to a miniature loudspeaker, which belongs to the technical field of electroacoustics and is suitable for mobile phones and portable sound reproduction equipment. According to an existing traditional moving-coil loudspeaker, a magnetic circuit system is arranged in the middle of the loudspeaker and becomes an overlapped part of blocking and thickness of axial vibration of the loudspeaker, the space utilization rate is not high, the linear stroke of the loudspeaker is small under the condition that the loudspeaker is limited by the thickness, and low-frequency development and improvement of sound quality are not facilitated. According to the micro loudspeaker (Figure 4), a magnetic circuit is made into a hollow frame body with a through axial opening and serves as a fixing frame, and a magnetic air gap is formed in the hollow portion of the hollow frame body. The diaphragm and the voice coil form an integrated flat diaphragm which is arranged in the magnetic air gap. The support folding ring is connected between the flat diaphragm and the magnet. The maximum vibration range of the loudspeaker is the maximum thickness of the loudspeaker, the maximum linear stroke is performed in a limited thickness space, and the loudspeaker has great advantages of improving low frequency, improving space utilization rate and improving sound quality.

Description

Technical Field

[0001] The present invention belongs to the technical field of electroacoustics and is a micro speaker for mobile phones and portable sound playback devices. Background Art

[0002] In existing traditional moving coil speakers, the magnetic circuit system is arranged in the middle of the speaker axially, becoming an obstacle to the axial vibration of the speaker and an additional part of the thickness. In speakers with small thickness requirements, it has limitations in increasing the maximum linear travel of the speaker, with low space utilization and difficulty in expanding low-frequency performance, which is not conducive to improving the sound quality. Summary of the Invention

[0003] The present invention is a new type of micro speaker. The inventive concept is that there are no components in front of and behind the voice coil and diaphragm of the moving coil speaker. When the voice coil and diaphragm vibrate, they are not blocked in front and behind, and the maximum vibration range of the diaphragm is the maximum axial thickness of the speaker. It uses a hollow frame body with openings at both axial ends as the magnetic circuit structure, which is composed of an outer magnetic conductive plate and a thin magnet. The hollow frame body also serves as the peripheral fixing frame of the speaker, and the fixing frame is the fixed basin frame, or simply called the basin frame. The axial direction is the axial direction of the speaker. The magnets are arranged concentrically symmetrically and with the same poles facing inwards. There is no magnetic conductive plate inside the magnet, and the magnetic force lines are emitted freely. The inner space of the basin frame is the magnetic air gap, which serves as the vibration interval of its vibration system. The vibration system includes a vibration component and a support component. The vibration component includes a voice coil and a diaphragm, and the support component is a surround, that is, the magnetic air gap serves as the common vibration interval for the voice coil and the diaphragm, and the surround is also entirely or partially placed in the magnetic air gap. Its magnetic and electrical distributions are as Figure 1 , the diaphragm and the voice coil are made into an integrated flat diaphragm and placed in the magnetic air gap. The voice coil is arranged close to the magnet and serves as the outer edge part of the flat diaphragm. The surround as the support component is connected between the outer edge of the flat diaphragm and the magnet ( Figure 2 ). Its working electrical and magnetic principles are as Figure 3 , and its structure is as Figure 4 .

[0004] The magnetic air gap of this new type of micro speaker is relatively large, and it is not easy to obtain a very high magnetic flux density. A strong magnet (above N45) must be used to make the magnetic circuit. Since the wide magnetic air gap serves as the vibration interval, it is relatively flexible to adjust the BL value and the vibration mass. For the sensitivity of a micro speaker, it is not the higher the better. If the sensitivity is too high, the low frequency will be lacking and it will be similar to a high-frequency speaker. Therefore, this new type of micro speaker does not have a negative impact on adjusting a relatively flat frequency characteristic. By adjusting the BL value and the vibration mass, and then cooperating with factors such as the compliance of the surround and the impedance of the voice coil, the sensitivity and the bandwidth can be adjusted to the requirements of actual use.

[0005] The magnetic circuit of this new type of micro speaker has an external loop and a large range of magnetic leakage. Acoustic transmission covers can be added at the front and back. The acoustic transmission covers have acoustic transmission holes and can have magnetic shielding functions. However, the uniform range of the magnetic air gap will further contract outward, and the center of gravity of the number of turns of the voice coil also needs to move outward accordingly. Connect the magnetic shielding cover to the outer magnetic conductive plate without contacting other surfaces of the magnet to reduce the contraction and the deterioration of the magnetic field line direction. For those without the acoustic transmission magnetic shielding cover, a dust-proof net or a protective grille can be set during later installation.

[0006] In the magnetic air gap of this new type of micro speaker, after the magnetic field lines uniformly emit from the magnet, the uniformity and direction gradually change in the direction close to the center. By arranging the voice coil close to the magnet, the speaker can still achieve low distortion.

[0007] Compared with the existing moving coil speakers, this new type of micro speaker can achieve the maximum linear travel in a limited thickness space, which has great advantages in enhancing low frequency, broadening the frequency band, improving power load, increasing space utilization rate, and improving sound quality. Description of the Drawings

[0008] Figure 1 , An axial schematic diagram of the magnetic and electrical distribution of a micro speaker. The outer frame with the shaded part is a hollow frame, the shaded part is the magnet, and the magnet has the same pole facing inward. The circular coil inside the frame represents the voice coil.

[0009] Figure 2 , A longitudinal sectional schematic diagram of a micro speaker. From the outside to the inside, they are the outer frame, the magnet, the surround, the voice coil, and the diaphragm in sequence.

[0010] Figure 3 , An electrical and magnetic schematic diagram of a micro speaker, which belongs to the working principle of an electro-dynamic speaker.

[0011] Figure 4 . A structural diagram of a micro speaker. From the outside to the inside, they are the outer frame, the magnet, the surround, and the flat diaphragm in sequence. The flat diaphragm includes the voice coil and the diaphragm. Detailed Implementation Manner

[0012] Manufacture a micro speaker with an axial area of about 2 square centimeters and an axial thickness of 6 millimeters (refer to the appendix Figure 4) Take a steel sheet with a thickness less than 0.5 mm and fold or press it into an outer frame. The axial height of the outer frame is 5 mm. Magnetize it in the thickness direction and use multiple strong magnets (N45 or above) with a thickness of 1.5 to 2 mm. The axial height of the magnets is 6 mm. Make the magnetic poles the same and face inward, and paste them on the inner side of the outer frame. The glued frame serves as the magnetic circuit and the speaker chassis, and the hollow part serves as the layout area for the flat voice coil diaphragm. The flat voice coil is wound from the inside out. The voice coil wire can use special enameled wire with a diameter of 0.05 mm to 0.08 mm. Leave a space in the middle of the voice coil that is more than half of the air gap width. It can be wound in a single layer or multiple layers, and the number of layers can increase in the outward direction. The outer edge of the voice coil is also the outer edge of the diaphragm. The voice coil can be wound around the diaphragm, or the voice coil can be wound and formed first and then the diaphragm is pasted, or a diaphragm is filled in the hollow part of the voice coil. The voice coil lead can directly use the voice coil tap wire or connect to a special lead wire. The weight of the flat voice coil diaphragm is controlled at about 0.1 g. The proportion of the voice coil in the flat diaphragm and the overall vibration mass can be controlled to determine the sensitivity and the low-frequency limit. These two parameters of sensitivity and low-frequency limit have a mutually restrictive relationship and require appropriate trade-offs. Focusing on sensitivity can reach more than eighty decibels, and focusing on the low-frequency limit can reach around one hundred hertz or even lower. In terms of the magnetic circuit frame, for the angular gap of the square magnet, it can be filled with plastic. The surround is connected to the outer edge of the flat voice coil diaphragm and the inner side of the outer frame magnet. Select a soft material with good stretching performance (such as silicone) as the surround. Input terminals are set at two corners, and the inside of the input terminals is connected to the voice coil lead. Air outlets can be set at the other two corners as the rear air outlets of the speaker.

Claims

1. A miniature loudspeaker, comprising a fixing frame, a magnetic circuit, a magnetic air gap, and a vibration system, wherein the vibration system comprises a vibration component and a supporting component, and the vibration component comprises a voice coil and a diaphragm, characterized in that: It combines the fixing frame and the magnetic circuit in a hollow frame, wherein the hollow portion of the hollow frame serves as the magnetic air gap, and the magnetic air gap serves as a layout interval and vibration interval shared by the voice coil and the diaphragm.

2. The micro-speaker according to claim 1, wherein: There is no component constituting the micro speaker in front of and / or behind the vibration component, or there is no other component constituting the micro speaker except the supporting component.

3. The micro-speaker according to claim 1, wherein: At the axial front end and / or rear end thereof, one or both of a sound-transmitting cover and a protective grille are included.

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