JP3657814B2 - Speaker - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a dynamic speaker such as a vehicle-mounted speaker, and more particularly to a heat dissipation structure for a lightweight speaker employing a small magnetic circuit.
[0002]
[Prior art]
In a vehicle-mounted speaker or the like, a resin frame is often used in order to reduce the weight, but in recent years, a speaker using a small magnetic circuit to promote further weight reduction is becoming widespread.
[0003]
That is, since a magnetic circuit configured by combining a magnet and a yoke becomes a heavy product when it is large, the weight of the entire speaker is greatly reduced when the magnetic circuit is downsized. In addition, if the magnetic circuit is small, the magnetic circuit cover made of a nonmagnetic material such as aluminum that houses and holds the magnetic circuit can also be made small, which is extremely advantageous in promoting weight reduction of the speaker.
[0004]
[Problems to be solved by the invention]
By the way, as described above, the surface area of the magnetic circuit and the magnetic circuit cover is greatly reduced in the speaker that employs a small magnetic circuit to reduce the weight. For this reason, the conventional lightweight speaker has a problem that the heat generated in the voice coil when it is energized and transmitted to the magnetic circuit is not easily released to the outside, and the temperature inside the speaker easily rises undesirably.
[0005]
[Means for Solving the Problems]
In the present invention, the back pressure generated when the diaphragm is vibrated is used so that air can smoothly flow between the magnetic circuit cover and the frame inside and outside the speaker. By doing so, the air inside and outside the speaker moves smoothly along the outer surface of the magnetic circuit cover due to the back pressure of the diaphragm when energized, and this air flow is conducted from the magnetic circuit to the magnetic circuit cover. Take away the heat. Therefore, even if a small magnetic circuit is adopted, the heat dissipation effect can be enhanced by the air cooling action, and it is possible to achieve both the promotion of weight reduction of the speaker and the suppression of the temperature rise.
[0006]
DETAILED DESCRIPTION OF THE INVENTION
In the speaker of the present invention, a voice coil, a magnetic circuit having a gap in which the voice coil is disposed, a magnetic circuit cover for housing and holding the magnetic circuit, and an inner peripheral portion are connected to the voice coil, and the voice coil A diaphragm that is driven when the coil is energized, a frame that is connected to the magnetic circuit cover and surrounds the back side of the diaphragm and supports the outer periphery of the diaphragm, and supports the inner periphery of the diaphragm In the loudspeaker including the damper, an opening is provided in the vicinity of the joint between the magnetic circuit cover and the frame, and the opening and the back side space of the diaphragm are communicated.
[0007]
In the speaker configured as described above, when the diaphragm vibrates when energized, the back pressure of the diaphragm acts on the back side space, and air circulation inside and outside the speaker is actively performed through the opening. The outer surface of the magnetic circuit cover is always exposed to fresh air when energized. Therefore, the heat generated by the voice coil when energized and transmitted to the magnetic circuit cover through the magnetic circuit is easily released by the air cooling action of the air entering and exiting through the opening, and a high heat dissipation effect can be expected.
[0008]
In the above configuration, the magnetic circuit cover has a large-diameter portion that supports the outer peripheral portion of the damper inside the frame, and an air flow passage that communicates between the large-diameter portion and the inner wall surface of the frame with the opening. If this is the case, this air flow passage acts as a so-called orifice, allowing air to flow extremely smoothly between the opening and the space on the back side of the diaphragm, and the large-diameter portion of the magnetic circuit cover to Since the heat dissipation area increases, the heat dissipation effect can be further enhanced.
[0009]
【Example】
The embodiment will be described with reference to the drawings. FIG. 1 is a rear view of a speaker according to an embodiment of the present invention, and FIG. 2 is a cross-sectional view taken along line A-O-B in FIG.
[0010]
The speaker shown in FIGS. 1 and 2 is a vehicle-mounted speaker that employs a small magnetic circuit to reduce the weight. This speaker includes a magnetic circuit cover 1 made of a nonmagnetic material having a high thermal conductivity such as aluminum, a magnetic circuit 2 made of yokes 2a, 2b and a magnet 2c, a resin frame 3 made of ABS resin, etc., and cone paper or A diaphragm 4 made of synthetic resin, a voice coil 6 wound around an outer peripheral surface of a cylindrical bobbin 5, and a damper 7 that supports the inner peripheral portion of the diaphragm 4 while allowing vibrations. A voice current is supplied to the voice coil 6 via a lead wire (not shown).
[0011]
A substantially annular large-diameter portion 1a projects from the top of the magnetic circuit cover 1, and the outer peripheral portion of the damper 7 is joined to the large-diameter portion 1a. The magnetic circuit cover 1 houses and holds a magnetic circuit 2, and a voice coil 6 is disposed in a gap G formed in the magnetic circuit 2. The resin frame 3 has a mortar-like appearance surrounding the diaphragm 4, the magnetic circuit cover 1 passes through the center of the bottom, and the rear ends of the four ribs 3 a formed on the back surface of the resin frame 3. Is connected to the magnetic circuit cover 1. However, openings 8 are provided at four positions along the outer peripheral surface of the magnetic circuit cover 1 (in contact with the outer surface) between the rear ends of the ribs 3a. 8 is located in the vicinity of the joint between the magnetic circuit cover 1 and the resin frame 3. The diaphragm 4 has an inner peripheral portion connected to the voice coil 6 via a bobbin 5, and an outer peripheral portion supported by the resin frame 3 via a deformed joint 9. As shown in FIG. 2, an air flow passage 10 is defined between the large-diameter portion 1 a of the magnetic circuit cover 1 and the inner wall surface of the resin frame 3. The opening 8 communicates with the space on the back side of the diaphragm 4.
[0012]
In the speaker schematically configured in this manner, when a voice current is applied to the voice coil 6 via a lead wire (not shown), the voice coil 6 vibrates due to electromagnetic force. Driven and vibrated, it is possible to perform loud sounds such as radio sound and CD playback sound. Further, when the diaphragm 4 vibrates in the vertical direction in FIG. 2 when energized, the back pressure of the diaphragm 4 acts on the back side space, and air flows inside and outside the speaker via the air flow passage 10 and the opening 8. Therefore, the outer surface of the magnetic circuit cover 1 is always exposed to fresh air when energized. Therefore, in this speaker, the heat (Joule heat) generated in the voice coil 6 when energized and transmitted to the magnetic circuit cover 1 via the magnetic circuit 2 is subjected to the air cooling action of the air that enters and exits through the opening portion 8 and goes outside. It is easy to be released. That is, if a small magnetic circuit 2 is used to promote weight reduction, the inside of the speaker tends to become hot due to a decrease in the heat dissipation area, but in this speaker, the air flow is opened without stagnation using the back pressure of the diaphragm 4. Since it passes through the portion 8, the amount of heat radiation from the outer surface of the magnetic circuit cover 1 increases due to the air cooling action.
[0013]
In addition, since this speaker has a structure in which the large-diameter portion 1a is protruded from the magnetic circuit cover 1 and the outer peripheral portion of the damper 7 is joined, the space between the large-diameter portion 1a and the inner wall surface of the resin frame 3 is between them. Naturally, the air flow passage 10 is formed, and the back pressure of the diaphragm 4 is easily shielded by the damper 7 and directly acts on the opening 8. That is, a so-called orifice is formed by the air flow passage 10 and the opening 8, and the flow rate of the air discharged from the opening 8 to the outside of the speaker is accelerated, so that the cooling action of the outer surface of the magnetic circuit cover 1 is further improved. Has become. Moreover, since the heat radiation area of the magnetic circuit cover 1 is increased by providing such a large diameter portion 1a, this speaker has a high heat radiation effect for suppressing an internal temperature rise, and hence the magnetic circuit 2 is small and light. High reliability is assured while achieving high reliability.
[0014]
In the embodiment described above, the space on the back side of the diaphragm 4 and the opening 8 are communicated with each other via the air flow passage 10 provided between the large diameter portion 1 a of the magnetic circuit cover 1 and the resin frame 3. However, the present invention is not limited to this. For example, in the case where the outer peripheral portion of the damper 7 is joined to the annular support portion protruding from the inner wall of the resin frame 3, if through holes are provided at a plurality of locations of the annular support portion, the through holes are provided through the through holes. Since the back side space of the diaphragm 4 and the opening 8 can be communicated, a similar heat dissipation effect can be expected.
[0015]
【The invention's effect】
The present invention is implemented in the form as described above, and has the effects described below.
[0016]
Since an opening is provided in the vicinity of the junction between the magnetic circuit cover and the frame, and the opening and the back side space of the diaphragm communicate with each other, when the diaphragm vibrates during energization, the diaphragm is placed in the back side space. The back pressure acts on the inside and outside of the speaker through the opening. Therefore, the outer surface of the magnetic circuit cover is always exposed to fresh air when energized, and the heat generated by the voice coil and transmitted to the magnetic circuit cover via the magnetic circuit when energized enters and exits through the opening. It becomes easy to be released by the air cooling effect of air. Therefore, even if a small magnetic circuit is adopted, the heat dissipation effect can be enhanced by the air cooling action, and both the promotion of weight reduction of the speaker and the suppression of the temperature rise can be achieved.
[0017]
Further, if the magnetic circuit cover is provided with a large-diameter portion that supports the outer periphery of the damper, and the air-flow passage that communicates between the large-diameter portion and the inner wall surface of the frame to the opening, the opening And the space on the back side of the diaphragm can flow air very smoothly, and the large diameter part of the magnetic circuit cover becomes a heat radiating part to increase the heat radiating area, further enhancing the heat radiating effect. it can.
[Brief description of the drawings]
FIG. 1 is a rear view of a speaker according to an embodiment of the present invention.
FIG. 2 is a cross-sectional view taken along the line AOB in FIG.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Magnetic circuit cover 1a Large diameter part 2 Magnetic circuit 3 Resin frame 3a Rib 4 Diaphragm 5 Bobbin 6 Voice coil 7 Damper 8 Opening part 10 Air flow path G Gap

Claims (2)

A voice coil, a magnetic circuit having a gap in which the voice coil is disposed, a magnetic circuit cover for housing and holding the magnetic circuit, and an inner peripheral portion connected to the voice coil and driven when the voice coil is energized. A diaphragm that is connected to the magnetic circuit cover and surrounds the back side of the diaphragm and supports the outer peripheral portion of the diaphragm; and a damper that supports the inner peripheral portion of the diaphragm. In the speaker,
An speaker, wherein an opening is provided in the vicinity of a joint between the magnetic circuit cover and the frame, and the opening and the back side space of the diaphragm are communicated. 2. The magnetic circuit cover according to claim 1, wherein a large-diameter portion that supports an outer peripheral portion of the damper is provided on the inner side of the frame, and the opening is provided between the large-diameter portion and the inner wall surface of the frame. The speaker is characterized by an air flow passage communicating with the speaker.

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