JPS6110400Y2 - - Google Patents

Description

[Detailed Description of the Invention] This invention relates to a coaxial speaker, and more specifically, to a coaxial speaker that is thin and suitable for use in a vehicle.

A coaxial speaker is constructed by arranging a bass diaphragm, a midrange, or a treble diaphragm on the same axis, and the sound image of the bass or treble range is located on the same axis, making it ideal. On the one hand, it has the characteristic that a sound field can be obtained, but because both the low and high speakers are arranged on the same axis, it has the disadvantage that the dimension in the axial direction becomes large. This drawback becomes particularly noticeable when applied to car speakers, as the depth dimension of the speaker unit is large, making it impossible to mount it on a door or in a place with a small rear space.

Therefore, recently, flat diaphragms have been developed, but since these diaphragms were developed for the purpose of generating plane waves, they require fairly high rigidity, and normally, Since it is constructed by pasting a skin material onto an aluminum honeycomb core, it is heavy and requires a large amount of driving force.

This idea aims to provide a coaxial speaker that can be used as an in-vehicle speaker by reducing the depth dimension, and for this purpose, a bimorph piezoelectric element is used in the driver of the high frequency speaker unit. This is a characteristic feature.

An embodiment of this invention will be described below with reference to the attached drawings. First of all, the figure is a vertical side view, and the reference numeral 1
indicates a cone-shaped diaphragm for low frequency range, the outer peripheral edge is supported by the speaker frame 3 via the edge 2, the inner peripheral edge is fixed to the voice coil bobbin 4,
This voice coil bobbin 4 is supported by the speaker frame 3 via a damper 5.

The voice coil 4a wound around the voice coil bobbin 4 is located in a magnetic gap formed between the center pole 6 and the top plate 7.
The center pole 6, top plate 7, magnet 8, pole yoke 9, etc. constitute a driver unit.

A plate-shaped damping material 11 is fixed to the end face of the voice coil bobbin 4 in order to absorb high-frequency vibrations of the voice coil bobbin 4 and prevent the vibrations from being transmitted to the piezoelectric element 12. A bimorph piezoelectric element 12 is fixed to the bimorph piezoelectric element 12, and a pair of lead wires 12a, 1 are connected to the bimorph piezoelectric element 12.
2b penetrates the diaphragm 1 and is led out to the outside of the speaker frame 3. This bimorph piezoelectric element 1
2, the center part 13a of the high-frequency diaphragm 13 is recessed and fixed, and the outer peripheral edge 13b of the high-frequency diaphragm 13 is fixed to the low-frequency cone-shaped diaphragm 1. There is. The inside of this high-frequency diaphragm 13 is filled with a sound-absorbing material 14 such as urethane foam, so that it is not affected by the vibrations of the low-frequency cone-shaped diaphragm 1.

Since the coaxial speaker of this invention has the above-described configuration, the high-frequency diaphragm 13 can drive the diaphragm by supplying audio current to the bimorph piezoelectric element 12, and in particular, the driver unit can be made thinner. Because of this, the overall depth of the speaker can be reduced, making it applicable to car speakers.

As is clear from the above description, the coaxial speaker of this invention has a driver unit made of a bimorph piezoelectric element provided via a damping material on the end face of the voice coil bobbin that constitutes the driver unit of the cone-shaped diaphragm for low frequencies. The bimorph piezoelectric element has a spherical shape with a concave center, the center is fixed, the periphery is fixed to a low-frequency cone-shaped diaphragm, and the internal space is filled with sound-absorbing material for high-frequency vibration. Since it is configured with a plate, it is possible to have the same depth as a multi-way speaker even though it is a coaxial speaker, and it is possible to obtain a thin speaker. Since sound propagation is insulated, clear playback sound can be obtained.

[Brief explanation of the drawing]

The accompanying drawing is a side sectional view of the coaxial speaker according to this invention. 11... Braking material, 12... Bimorph piezoelectric element, 13... High frequency diaphragm, 14... Sound absorbing material.

Claims (1)

[Scope of utility model registration request] A dynamic coaxial speaker equipped with a cone-shaped diaphragm includes a bimorph piezoelectric element fixed to the end face of a voice coil bobbin via a damping plate, and a spherical shape with a concave center, the center of which is connected to the bimorph piezoelectric element. , a coaxial speaker comprising a treble diaphragm whose peripheral portions are each fixed to a cone-shaped diaphragm and whose inner space is filled with a sound absorbing material.