Patent Translate Powered by EPO and Google Notice This translation is machine-generated. It cannot be guaranteed that it is intelligible, accurate, complete, reliable or fit for specific purposes. Critical decisions, such as commercially relevant or financial decisions, should not be based on machine-translation output. DESCRIPTION JPH0458700 [0001] BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a dome-shaped diaphragm effective as a diaphragm for middle and high-tone speakers. 2. Description of the Related Art In recent years, dome-shaped speakers are widely used as midhigh pitched speakers, and it is desirable to increase the high frequency reproduction limit frequency as much as possible. Heretofore, among various dome shapes, one having the same dome weight and having the same spherical surface is considered to have the highest high frequency reproduction limit frequency, and the dome having the spherical shape as shown in FIG. Could be used. Hereinafter, a conventional dome-shaped diaphragm will be described. As shown in FIG. 2, the voice coil bonding portion 2 is a vertical portion to which the bobbin of the voice coil is fitted and bonded, and the voice coil vibration is transmitted to the dome portion. The edge bonding portion 3 is a horizontal collar for bonding an edge that supports the entire diaphragm to which the voice coil is bonded. The dome portion 1 has a shape in which a part of a spherical surface formed by a constant diameter is cut. FIG. 3 shows the sound pressure frequency characteristics of a conventional dome-shaped high-sounding speaker with a diameter of 2 cm using a spherical dome portion in dotted lines. This diaphragm material is a 50-micronthick laminated mica, and the dome shape is a spherical surface with a diameter of 32 mm cut at a height of E 3.4 mm. The weight of the diaphragm is 70 mg in total of the dome part, the voice coil bonded part, the work and the toe bonded part. As shown in the figure, there is a peak at 30 KHz, which is the first order high frequency resonance frequency. In the case of a dome-shaped speaker, since the first high-frequency resonance frequency is regarded as a high-frequency reproduction limit frequency, the high-frequency reproduction limit of this 2.5 cm-diameter dome-type high-sound speaker using a conventional spherical dome-shaped diaphragm The frequency is 30 KHz. Problems to be Solved by the Invention In the dome-shaped speaker using such a conventional dome-shaped diaphragm, the material of the diaphragm is thickened in order 11-05-2019 1 to increase the high-frequency reproduction limit frequency, ie, the first high-frequency resonance frequency. If the shape of the dome portion has to be made a deeper spherical surface, then the weight of the diaphragm is increased and the sound pressure level of the speaker is lowered. The present invention solves the above problems, and provides a dome-shaped diaphragm in which the high frequency reproduction limit frequency is increased without increasing the weight of the diaphragm. Means for Solving the Problems In order to achieve the above object, the present invention can make an ellipse whose major axis is 1.1 to 2 times longer than the minor axis, with the minor axis as the axis of rotation. A small portion of the flat ellipsoidal rotor surface, which can be cut by a plane perpendicular to the rotation axis, has a dome shape. The present invention has the above-described configuration, while the weight of the conventional spherical dome is the same, but the strength of the inner circumferential portion of the dome is lowered, and the slope of the dome outer circumferential portion is further reduced within 0 range It can be made larger and the first higher resonance frequency can be raised. Embodiment An embodiment of the present invention will be described below with reference to FIGS. 1 and 3. FIG. As shown in FIG. 1, the voice coil bonding portion 2 is a vertical portion to which the bobbin of the voice coil is fitted and bonded, and the voice coil vibration is transmitted to the dome portion 4. Mata and edge bonding portions 3 are horizontal collars for bonding edges supporting the entire diaphragm to which the voice coil is bonded, and these are the same as conventional ones. On the other hand, the dome portion 4 is a flat elliptical rotary body surface formed by using an ellipse whose major axis is 1.1 to 2 times longer than the minor axis and whose minor axis is the rotational axis, the plane perpendicular to the rotational axis The small part that can be cut by using is the shape. The operation of the above configuration will be described. First, it is well known that it is necessary to increase the slope of the dome near the voice coil, that is, the slope of the dome outer periphery, in order to increase the first high-order resonance frequency of the dome-shaped diaphragm. However, simply increasing the slope of the dome periphery increases the weight of the entire dome. That is, if the inner peripheral portion is not lightened by an increase in the weight of the outer peripheral portion due to an increase in the slope of the dome at the outer peripheral portion, the overall weight is increased. However, in the present invention, since the dome section cross-sectional shape is a flat ellipse, in addition to the large gradient of the dome outer peripheral part, the gradient of the dome inner peripheral part becomes small conversely, the weight of the dome inner peripheral part is reduced. It is possible. In addition, if the slope of the inner peripheral part of the dome is too small, the strength of the inner peripheral part may be reduced to cause abnormal resonance at a low frequency or to lower the first high-resonance frequency. In the present invention, since the length of the major axis is 1.1 to 2 times the length of the minor axis, the slope of the inner periphery of the dome does not become too small. As a result, although having the same weight as the conventional spherical dome, the strength of the inner peripheral portion of the dome is lowered, and the first high-resonance frequency can be increased without occurrence of 11-05-2019 2 abnormal resonance or the like. The solid line in FIG. 3 shows the sound pressure frequency characteristics of the dome-shaped high-tone speaker of 2.5 cm in diameter using the domeshaped diaphragm of the embodiment of the present invention. The diaphragm material is a 50 micron thick laminated mica as in the prior art. The dome shape is a small portion formed by cutting an ellipse having a major axis of 27.74 mm 5 and a minor axis of 19 ° 62 mm with the minor axis direction as the rotational axis, in a plane perpendicular to the rotational axis of the flat ellipsoid rotary body surface, Its height is 6.02 mm. The weight of the diaphragm is <70 mg, which is the same as that of the conventional example, as a total of the dome portion 4, the voice coil bonding portion 2 and the edge bonding portion 3. As shown in the figure, it can be seen that the first order high resonance frequency extends to 33 KHz. Not only that, in the prior art there is a second peak around 50 KHz, and the sound pressure frequency characteristics are uneven above the first higher resonance frequency, whereas the one according to the present invention is the first The sound pressure frequency characteristic is gently attenuated above the high resonance frequency, and there is also an effect that the unnecessary resonance sound is small. In the embodiment of the present invention, the dome-shaped diaphragm includes the dome portion 4, the voice coil bonding portion 2, and the edge bonding portion 3, but the type without the edge bonding portion or the voice coil bobbin and the dome portion are integrally molded. It goes without saying that other types of dome diaphragms and other types of dome diaphragms are also effective. As apparent from the embodiments of the present invention as described above, according to the present invention, although the weight of the conventional spherical dome is the same, the strength of the inner periphery of the dome is lowered to cause abnormal resonance and the like. Since the slope of the dome outer peripheral portion can be made larger within the range where there is no noise, it is possible to raise the high frequency reproduction limit frequency without increasing the diaphragm weight. In addition, the sound pressure frequency characteristic is gently attenuated above the first high-order resonance frequency, and there is also an effect that the unnecessary resonance sound is small, and the practical effect is extremely large. [0002] Brief description of the drawings [0003] FIG. 1 is a sectional view of a dome-shaped diaphragm according to an embodiment of the present invention, FIG. 2 is a sectional view of a conventional dome-shaped diaphragm, and FIG. 3 is an aperture using the dome-shaped diaphragm according to an embodiment of the present 11-05-2019 3 invention It is a sound pressure frequency-characteristics figure of a 2.5 cm-diameter domeshaped high-sound speaker using a 2.5-cm dome-shaped high-sound speaker and a conventional dome-shaped diaphragm. 2 ... voice coil bonding portion, 3 ... edge bonding portion, 4 ... dome portion. Agent's Name Attorney Attorney Kanno Weight Ha or 1 Person C Su Ibaraki 11-05-2019 4
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