JP4749402B2 - Diaphragm for electroacoustic transducer - Google Patents

Description

  The present invention relates to a diaphragm for an electroacoustic transducer, and more particularly to a substantially dome-shaped diaphragm having an irregular cross section.

  There are various types of diaphragms such as a cone shape and a flat plate shape for low sound reproduction and medium sound reproduction, and there are diaphragms formed in a dome shape for high frequency reproduction.

The dome-like diaphragm has a circular planar shape and a semicircular side shape, and is formed in a semispherical shape as a whole. As is well known, a driving voice coil placed in a magnetic circuit is coupled to the diaphragm, so that the vibration of the voice coil is transmitted to the diaphragm and a sound is emitted to the front surface.
JP-A-5-328488

  However, in such a dome-shaped diaphragm, the length of the apex of the diaphragm and the outer peripheral portion to which the voice coil is coupled are equal at any position on the circumference. Since the transmitted vibrations are concentrated in the same phase on the top of the diaphragm, there is a problem that resonance easily occurs and it is difficult to obtain good sound quality.

  The present invention has been proposed in view of the above, and an object of the present invention is to provide a substantially dome-shaped electroacoustic transducer diaphragm having good sound quality.

According to the first aspect of the present invention, in the electroacoustic transducer diaphragm in which the outer peripheral shape is formed in a circular shape and the overall shape is formed in a substantially dome shape, the ridge line 2 extending to the outer periphery through the dome apex portion 0 is substantially S. A character-shaped ridge line 2 is formed , and a left-right asymmetric curved surface shape is formed with the ridge line 2 as a boundary.

  In the present invention, the ridge line passing through the top of the dome is substantially S-shaped, and a left-right asymmetric curved surface can be formed and resonance can be dispersed, so that a large high-frequency peak can be reduced and frequency characteristics can be improved. Can be obtained, and the sound quality is improved.

  An embodiment of the present invention will be described below with reference to the drawings.

  1 is a perspective view of a substantially dome-shaped diaphragm according to the present invention, FIG. 2 is a plan view, FIG. 3A is a cross-sectional view taken along line AA in FIG. 2, and FIG. B line sectional drawing and FIG.3 (c) show CC line sectional drawing in FIG.

  As shown in FIG. 1, the diaphragm 1 for an electroacoustic transducer according to the present invention has a circular outer periphery shape, a circular dome shape as a whole, and a substantially ridge line extending to the outer periphery through the dome apex portion. The ridgeline 2 is shaped like a shape, and in the state shown in the figure, the left and right diaphragm shapes with the ridgeline 2 as a boundary are formed into a left-right asymmetric curved surface.

  The ridge line 4 extending in the radial direction substantially perpendicular to the dome 2 with respect to the ridge line 2 is a dome apex part at the center as shown in the cross-section of FIG. 0 is located, and the length and the radius of curvature of the first and second ridgelines 4a and 4b on the left and right sides are equal.

  2, in the cross section along the line AA on the right side of the dome center 0, as shown in FIG. 3A, the ridge line 3 is composed of left and right third and fourth ridge lines 3a and 3b, and the curvature radius thereof is The first ridgeline 3a having a long length has a small radius of curvature, and the second ridgeline 3b having a short length is formed with a large radius of curvature.

  Further, in FIG. 2, in the CC cross section on the left side of the dome apex portion 0, as shown in FIG. 3 (c), the ridge line 5 is composed of left and right fifth and sixth ridge lines 5a and 5b. The curvature radius of the fifth ridge line 5a having a short length is large, and the curvature radius of the sixth ridge line 5b having a long length is small.

  Therefore, the vibration transmitted through the voice coil does not concentrate in the same phase on the top of the diaphragm, and resonance hardly occurs.

The electroacoustic transducer diaphragm 1 having this shape is preferably manufactured by molding aluminum foil or magnesium foil as a material thereof, and a voice coil (the other end of which is arranged in the magnetic gap of the magnetic circuit so as to vibrate). One end of (not shown) is coupled.
Further, the outer peripheral portion is incorporated into the speaker by being fixed to a frame (none of which is shown) via an edge.

  In a simple dome-shaped diaphragm, when the vibration mode is actually measured by simulation of the free vibration mode by the finite element method, the shape is a dome shape, so that a substantially ring-shaped axisymmetric mode is generated on the outer periphery of the apex. However, since the diaphragm according to the present invention has an irregular cross-sectional shape, the axial target mode that spreads radially from the apex is not seen, and the resonance points are dispersed.

  FIG. 4 shows the frequency characteristics of a speaker provided with a diaphragm according to the present invention. The horizontal axis is frequency and the vertical axis is sound pressure. FIG. 5 shows the frequency characteristics of a conventional speaker having a simple dome-shaped diaphragm.

  In the conventional product, a large peak is observed on the high frequency side. However, in the product of the present invention, the large peak in the high frequency is reduced, the peak dip is reduced compared to the conventional product, the characteristics are flat, and the sound quality is improved.

  Of course, the present invention can also be applied to a diaphragm in which an inverted dome is bent toward the back side, that is, the magnetic circuit side.

The perspective view of the diaphragm for electroacoustic transducers concerning one example of the present invention is shown. The top view of the diaphragm for electroacoustic transducers concerning one Example of this invention is shown. 2A is a sectional view taken along line AA in FIG. 2, FIG. 2B is a sectional view taken along line BB in FIG. 2, and FIG. 2C is a sectional view taken along line CC in FIG. The frequency characteristic of the speaker incorporating the diaphragm for electroacoustic transducers of the present invention is shown. The frequency characteristics of the conventional product are shown.

Explanation of symbols

0 Dome vertex 1 Diaphragm 2, 3, 4, 5 Edge line 3a First edge line 3b Second edge line 4a First edge line 4b Second edge line 5a First edge line 5b Second edge line

Claims (1)

In the electroacoustic transducer diaphragm in which the outer peripheral shape is formed in a circular shape and the overall shape is formed in a substantially dome shape,
A ridge (2) substantially S-shaped edge lines (2) extending to the outer periphery through the dome apex 0 and asymmetrical curved shape bordering the ridge (2),
A diaphragm for an electroacoustic transducer.

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