JPS61116499A - Loudspeaker - Google Patents

Abstract

PURPOSE:To obtain a flat frequency characteristic by heat-forming a diaphragm from a resin film, and providing an arc-shaped slit on the flat edge part of its outer circumference. CONSTITUTION:The flat edge part is integrally formed on the outer circumference of the diaphragm by heat-molding the resin film so that the compliance of the edge part may be increased. Next, co-centric arc-shaped slits are formed continuously by remaining the bindings with 1-2mm width so that the movability of the edge part is increased to reduce the resonant frequency. And, to increase the inner loss due to the deformation of edge part, the edge part is controlled by attaching the adhesive tape at the rear side of it to prevent the resonance. Further, by lowering the hardness of the edge part, the rolling of the diaphragm is prevented and its effective area is increased and the deterioration of acoustic pressure is prevented. Since the resonance of the edge is difficult to occur, the output acoustic pressure frequency curve shows up to be flat without the generation of creset and trough, and the output acoustic pressure level is improved.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a speaker used in electroacoustic equipment. 5 (Configuration of conventional example and its problems) A conventional speaker will be explained with reference to FIG. In the figure, the speaker has an annular magnetic gap 4 formed by an arm-shaped yoke 1 and a disk-shaped top plate 3 fixed to the center thereof via a magnet 2. A voice coil 6 coupled to the diaphragm 5 is inserted, and the diaphragm 5 is attached to the outer circumferential surface of the arm-shaped yoke 1 by an adhesive part 8 on the periphery of an edge part 7 integrally formed on the outer periphery of the diaphragm 5.
A frame 9 holding a frame 9 is fitted and fixed.

The above-mentioned diaphragm 5 is formed by heat-molding a polyester resin film or the like, and the edge portion 7 and peripheral adhesive portion 8 are integrally formed. Furthermore, the edge portion 7 is formed into a waveform in order to prevent edge resonance and lower the lowest resonant frequency of the diaphragm 5.

However, since the edge portion 7 is integrally formed of the same material as the diaphragm 5, it is not possible to increase the internal loss by the edge portion 7, and therefore it is not possible to prevent the occurrence of edge resonance. For this reason, there is a problem in that a valley appears in the output sound pressure frequency curve. In addition, in order to lower the lowest resonance frequency, it is necessary to increase the compliance of the edge portion 7, but since the diaphragm 5 and the edge portion 7 are integrally molded, it is possible to make only the edge portion 7 thinner or softer. There was also the problem that it was extremely difficult to lower the lowest resonant frequency. Furthermore, since the edge portion 7 is formed in a wave shape, the edge portion 7 is reinforced and has greater rigidity than the diaphragm 5 portion, which causes the diaphragm 5 portion to bend, making it easy to cause a rolling phenomenon. There are also problems in that the voice coil 6 tends to vibrate laterally in the magnetic gap 4, which is a so-called gap defect, and the effective radius of the diaphragm 5 becomes smaller, resulting in a lower output sound pressure level.

(Objective of the Invention) The present invention solves the above-mentioned drawbacks, and uses a diaphragm in which the edges of the diaphragm are integrally molded using a resin film, thereby reducing the lowest resonant frequency and enabling broadband reproduction. In addition, the present invention aims to provide a speaker having flat frequency characteristics without peaks or valleys in the output sound pressure frequency curve. (Structure of the Invention) In order to achieve the above object, the present invention The edge part, which is integrally formed on the outer periphery of the diaphragm by heat molding a resin film, is made flat to increase the compliance of the edge part, and one or two arc-shaped slits drawing concentric circles are connected to the edge part. The slits are provided continuously, leaving a gap, to make the edges easier to move and lower the lowest resonant frequency.In addition, in order to increase internal loss due to deformation of the edges, adhesive tape is pasted on the back of the slits to apply braking. , which attempts to prevent edge resonance. Furthermore, by reducing the rigidity of the edge portion, the rolling phenomenon of the diaphragm is prevented, the effective area thereof is increased, and the sound pressure level is prevented from decreasing.

(Explanation of Examples) Embodiments of the present invention will be explained with reference to FIGS. 2 to 4.

FIG. 2 is a cross-sectional view of a speaker according to an embodiment of the present invention, in which a flat edge portion 1° and an adhesive portion 8 are formed on the outer periphery of the diaphragm 5 by heat molding a polyester resin film, etc. The device is the same as the conventional example shown in FIG. 1 except that an adhesive tape 11 is attached to the back side of the device.

FIGS. 3(a) and 3(b) are a plan view and a sectional view of the diaphragm and edge portion of an embodiment of FIG. 2, respectively, as seen from the side. slit 12
Concentric circles are drawn with the 13th and 13th connecting moons of width 1 or 2,
The adhesive tape 11 is shown attached to the back surface of the edge portion 1o.

FIG. 4 is a plan view showing the diaphragm and edge portion of another embodiment of the present invention.
4 and 15, and joints 16 and 17 are provided by shifting these by 1/2 pitch from each other.

In this way, the softness of the edge part 1o increases the stiffness compliance, so the lowest resonance frequency 11<' decreases, and the increase in the internal loss of the edge part makes it difficult for shedge resonance to occur, so the output sound pressure frequency curve becomes broadband. Flat frequency handling with no peaks or valleys was achieved, and the output sound pressure level was further improved.

The adhesive tape 11 attached to the back surface of the edge portion 10 also serves to prevent foreign matter from entering the speaker through the slits 12, 14 and 15.

(Effects of the Invention) As explained above, according to the present invention, the diaphragm and the edge portion are integrally formed by heat molding a resin film, and the lowest resonant frequency is lowered, resulting in a flat output sound pressure over a wide band. A speaker having frequency characteristics can be obtained. Furthermore, by increasing the effective area of the diaphragm, the sound pressure level can be improved.

[Brief explanation of the drawing]

FIG. 1 is a sectional view of a conventional speaker, FIG. 2 is a sectional view of a speaker according to an embodiment of the present invention, and FIGS.
b) is a plan view and a sectional view of the diaphragm and edge portion of one embodiment of the present invention in FIG. 2, and a sectional view seen from the side, respectively, and FIG. be. 1... Yoke, 2... Magnet, 3... Top play 1., 4... Magnetic gap, 5... Vibration plate, 6...
・Voice coil, 7.10... Edge part, 8... Adhesive part, 9... Frame, 11... Adhesive tape, 12
, 14.15...slit , 1 3
, 1 6 , '1 7 ... connection
Ki ``''. Figure 1 Figure 2

Claims (1)

[Claims] In a speaker in which a voice coil coupled to a diaphragm is inserted into the magnetic gap of the field part, and a frame holding the outer periphery of the diaphragm via the edge part is fixed to the field part, a resin film is heated. The diaphragm and the flat edge part of its outer periphery are formed into one piece by molding, and concentric arc-shaped slits are continuously provided on the flat edge part, leaving a narrow joint. A speaker characterized by adhesive tape pasted on the back side of the slit part.