JP4520311B2 - Diaphragm for electroacoustic transducer - Google Patents

Description

  The present invention relates to a cone-type diaphragm for an electroacoustic transducer, and more particularly to a diaphragm for an electroacoustic transducer in which split resonance is dispersed.

  The diaphragm used in the conventional general speaker is conical, and the diaphragm shape is symmetric with respect to the central axis of the diaphragm, and since the half apex angle is constant, a specific vibration mode is likely to appear. As a dip or peak, it had an effect on the playback bandwidth.

  Various methods have been devised as means for solving the above.

  For example, Japanese Patent Laid-Open No. 9-37385 discloses a configuration in which a slit is provided in the middle or near the outer periphery from the outer periphery to the inner periphery of a conical diaphragm and is closed with a sealing material or a viscoelastic material. This diaphragm excites a non-axisymmetric resonance mode by a slit to disperse the resonance.

  As another example, as seen in Japanese Patent Laid-Open No. 11-205895, a contour plate of a curved surface from the outer periphery to the inner periphery is polygonal and changes in a circular shape toward the voice coil joint, and a diaphragm A speaker using a roll edge that has a polygonal shape and a circular shape toward an outer diameter is disclosed. This is intended to disperse the concentric resonance generated at the roll edge.

Further, JP 2000-354289A discloses a diaphragm in which the height between the outer periphery of the substantially conical diaphragm and the joint with the voice coil bobbin provided concentrically changes continuously. This changes the frequency of the split resonance by changing the half apex angle along the entire circumference of the cone and changing the length of the bus.
JP-A-9-37385 JP-A-11-205895 JP 2000-354289 A

  However, as in the above-mentioned JP-A-9-37385, in the configuration in which a slit is provided in the middle or near the outer periphery from the outer periphery to the inner periphery of the conical diaphragm and closed with a sealing material or a viscoelastic material, the slit portion is The process of providing and sticking a seal | sticker, apply | coating and closing a viscoelastic material, etc. is complicated, and causes a high cost.

  In addition, as in JP-A-11-205895, curved contour lines from the outer periphery to the inner periphery are polygonal, and a bonded portion of the diaphragm and the diaphragm that changes in a circular shape toward the voice coil joint portion is provided. A polygonal shape using a roll edge that changes to a circular shape toward the outer shape has a complicated shape, so that the mold cost is very expensive, the manufacturing process becomes complicated, and the cost increases.

  Further, as in JP-A-2000-354289, the shape of the diaphragm in which the height between the outer periphery of the substantially conical diaphragm and the joint with the voice coil bobbin provided concentrically varies is also complicated. Therefore, the mold cost is high, the manufacturing process is complicated, and the cost is increased.

  SUMMARY OF THE INVENTION In view of the above, an object of the present invention is to provide a diaphragm that is easy to manufacture while dispersing the frequency of split resonance in a simple shape in a cone-shaped diaphragm having a circular outer periphery.

According to the first aspect of the present invention, in the cone-shaped diaphragm having a circular outer periphery, the height h from the voice coil bobbin joint 1 on the inner periphery of the cone-shaped diaphragm 2 to the outer peripheral edge is constant, and the cone-shaped diaphragm 2 The length of the inner circumference from the voice coil bobbin joint 1 to the outer circumference continuously changes , and the inner circumference shape of the cone-shaped diaphragm 2 is substantially a track shape or an oval shape .

  According to the present invention, the height from the voice coil bobbin joint on the inner periphery of the cone type diaphragm to the outer peripheral line is made constant, and the length from the voice coil bobbin joint to the outer circumference of the cone type diaphragm is continuously changed. Since the half apex angle is continuously changed, it is possible to disperse the divided resonance, and thus it is possible to secure a flat and wide reproduction band.

  Moreover, since the shape is simple, it can be manufactured easily and inexpensively.

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

  FIG. 1 is a plan view of an embodiment of the present invention, FIG. 2 is a side view taken along the line B-B ′ in FIG. 1, and the right half portion is shown by a cross section taken along the line O-B ′ in FIG. FIG. 3 is a side view of A-A ′ in FIG. 1, and the right half portion is shown by a cross section along O-A ′ in FIG. 1. 4 is an enlarged view of the right half of FIG. 2, and FIG. 5 is an enlarged view of the right half of FIG.

  In these drawings, reference numeral 1 denotes a voice coil bobbin joint having a pair of long sides 1a having straight portions, a pair of short sides 1b having an arc shape, and arc-shaped corner portions 1c therebetween, and having a substantially track shape. Reference numeral 2 denotes a cone-type diaphragm formed on the outer periphery thereof and having a circular outer periphery, and 3 denotes an up-roll-type roll edge in which the inner peripheral edge is joined to the outer peripheral edge of the cone-type diaphragm 2.

  2 to 5, the characteristic feature of the present invention is that the height from the front end of the voice coil bobbin joint 1 on the inner periphery of the cone-type diaphragm 2 to the outer peripheral edge that is the front end of the cone-type diaphragm 2 is high. The h is constant.

  Then, by making the outer shape of the voice coil bobbin joint portion 1 substantially a track shape, the length from the voice coil bobbin joint portion 1 to the outer peripheral edge of the inner periphery of the cone-shaped diaphragm 2 is continuously increased as shown in FIG. It has changed.

That is, as can be seen from FIG. 1, the length l ₁ from the front end of each linear long side portion of the voice coil bobbin joint 1 having a substantially track shape to the outer peripheral edge of the cone-shaped diaphragm 2 is the longest, and is in an arc shape. The length l ₃ from the formed corner portion to the outer peripheral edge of the cone-shaped diaphragm 2 is shorter than the length l _{1, and the} length l from the apex of the short side portion forming the arc shape to the outer peripheral edge of the cone-shaped diaphragm 2 ₂ is the shortest, and the length is continuously changed along the shape of the voice coil bobbin joint 1.

The height h from the inner periphery to the outer periphery of the cone-type diaphragm 2 is made constant, and the length of the outer periphery from the voice coil bobbin joint 1 to the cone-type diaphragm 2 is changed. As shown in FIG. 5, the half apex angle θ ₁ of the length l ₁ portion is different from the half apex angle θ ₂ of the length l ₂ portion, and the half apex angle along the outer periphery of the cone-shaped diaphragm 2 Changes continuously.

  In this way, the length from the voice coil bobbin joint 1 to the outer peripheral edge of the cone type diaphragm 2 is continuously changed, and the half apex angle θ of the voice coil bobbin joint 1 of the cone type diaphragm 2 is accordingly changed. By changing continuously, the rigidity is partially changed, and the split resonance of the cone-type diaphragm 2 is dispersed.

  That is, the radial regions of the long side portion, the corner portion, and the top of the arc-shaped short side portion of the voice coil bobbin joint portion 1 of the cone-shaped diaphragm 2 have different rigidity, and the corner portion and the short portion are shorter than the long side region. Rigidity is improved by curving the side region.

  Resonance is dispersed by changing the rigidity of the voice coil bobbin joint 1, that is, the diaphragm neck, and it is difficult to produce a peak in frequency characteristics.

  Although not specifically shown, a voice coil having a corresponding shape is joined to the voice coil bobbin joint 1 and this voice coil is disposed in a magnetic gap of an internal magnetic type or external magnetic type magnetic circuit. Further, the acoustic transducer can be assembled by supporting the voice coil via a damper, joining the outer peripheral portion of the roll edge 3 to the outer peripheral portion of the frame, and arranging a magnetic circuit at the bottom of the frame.

  FIG. 6 shows the frequency characteristics of the product of the present invention in which the assembly half apex angle is continuously changed in this way and the conventional product having a constant half apex angle. A is a product of the present invention, and B is a conventional product. According to the present invention, since the divided resonance is dispersed, the frequency characteristics are flat, a wide reproduction band is obtained, and the sound quality can be improved.

  In the embodiment shown in FIG. 1, the outer shape of the voice coil bobbin joint 1 is substantially track-shaped, but similar effects can be obtained even with an oval (ellipse).

  In addition, the height from the voice coil bobbin joint to the outer peripheral edge of the inner periphery of the cone type diaphragm is made constant, the shape of the voice coil bobbin joint 1 is made polygonal, and the length from the voice coil bobbin joint to the outer periphery of the cone type diaphragm The same effect can be obtained even when the thickness is continuously changed.

The top view of one Example of this invention is shown. FIG. 2 is a partial cross-sectional side view taken along line B-B ′ in FIG. 1. FIG. 2 is a partial cross-sectional side view taken along line A-A ′ in FIG. 1. The expansion explanatory view of the right half of Drawing 2 is shown. The expansion explanatory view of the right half part of Drawing 3 is shown. The frequency characteristics of the conventional product and the product of the present invention are shown.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Voice coil bobbin junction part 2 Cone-type diaphragm 3 Roll edge h Height from a voice coil bobbin junction part to cone type diaphragm outer periphery [theta] ₁ , [theta] ₂ half apex angle

Claims (1)

In the cone-shaped diaphragm having a circular outer periphery, the height (h) from the voice coil bobbin joint (1) to the outer peripheral edge of the inner periphery of the cone-shaped diaphragm (2) is constant, and the cone-shaped diaphragm (2 ) Continuously changes from the voice coil bobbin joint (1) to the outer periphery , and the inner peripheral shape of the cone-shaped diaphragm (2) is substantially a track shape or an oval. A diaphragm for an electroacoustic transducer.

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