JPH03126400A - Voice coil bobbin for speaker - Google Patents

Abstract

PURPOSE:To eliminate transmission loss from a voice coil bobbin to a diaphragm by constituting the bobbin with 3-axis wove ncloth in which two wefts combined in X-shape are crossed to one warp at an opposite angle. CONSTITUTION:The bobbin is constituted with a 3-axis woven cloth comprising 3 warps 105a-105c in which two wefts 105b, 105c combined in X-shape are crossed one warp 105a at an opposite angle of 40-80 deg.. Thus, anisotropy is eliminated and isotropy is established, then Young's modulus in every direction is equal, non-axis symmetry vibration hardly takes place and the transmission loss from a voice coil bobbin 105 to a diaphragm is eliminated.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to improvements in voice coil bobbins used for speakers.

[Prior Art] Fig. 3 is a cross-sectional view showing the main parts of a conventional speaker of this type. A magnet is fixed on the top, (3) is a plate provided on this magnet, (4) is a frame fixed on this plate (3), and (5) is a link between the protrusion (la) and the plate (3).
), the voice coil bobbin (7) has its voice coil (6) located in the gap between the voice coil bobbin (5).
), the diaphragm (8) is connected to the top of the diaphragm (7).
), and (9) is a spider stretched between the voice coil bobbin (5) and the frame (4).

The conventional voice coil bobbin (5) is made of paper, aluminum, or glass fiber cloth in which the warp (5a) and weft (5b) are woven at a 90 degree crossing angle as shown in Figure 4. There is.

By the way, the conditions required for the voice coil bobbin (5) are: ■ High rigidity, ■ Excellent heat resistance, ■
It is required to be stable against temperature and humidity, and not deform due to external force (bottom contact against large input).

Conventional materials for the voice coil bobbin (5) include paper, aluminum, synthetic resin, or glass fiber cloth in which the warp (5a) and weft (5b) are crossed at 90 degrees as shown in Figures 4 (a) and (b). It is used.

[Problems to be Solved by the Invention] When the conventional voice coil bobbin (5) is made of the above-mentioned paper, it is lightweight, but has low rigidity and low heat resistance, deforms due to temperature and humidity, and is not susceptible to large inputs. When bottoming out occurs, there are problems such as buckling.

In addition, synthetic resins have the problem of low heat resistance.
Aluminum has great rigidity, but when current is applied to the coil (6), the voice coil vibrates up and down, creating eddy currents in the bobbin and causing unnecessary electromagnetic braking. In addition, as shown in Figure 4 (a) and (b), a bobbin made of glass fiber cloth in which the warp and weft threads intersect at a 90 degree angle has a strength in the thread direction as shown in Figure 5 (at). Although it is large, the strength in the 45 degree direction is small and has anisotropy, so a non-axisymmetric vibration mode occurs in the voice coil bobbin, causing a transmission loss to the diaphragm.

This invention was made to solve the above problems, and it eliminates the anisotropy of the voice coil bobbin material, prevents the generation of non-axisymmetric vibration modes that occur in the voice coil bobbin, and further increases the rigidity of the voice coil bobbin. The purpose is to obtain a voice coil bobbin that is strong against bending.

[Means for solving the problem] The voice coil bobbin f105) in the case of this invention is composed of a woven fabric composed of three woven threads (105a) (105b) (105cl), and two X-shaped It has a triaxial weave in which the combined weft threads intersect one warp thread at an angle of 60 degrees, and both the weft thread and the warp thread have a high elastic modulus. For example, Kepler threads are used.

[Function] The voice coil bobbin according to the present invention has three functions as described above.
Since it is composed of a axial weave fabric, there is no anisotropy and equi-Δ property is achieved, so the Young's modulus in all directions is equal as shown in Figure 5(b), and non-axial Symmetrical vibrations are less likely to occur, eliminating transmission loss from the voice coil bobbin to the diaphragm.

[Example] An example of the present invention will be described below. That is, in FIG. 1(a), (105) is the voice coil bobbin of the present invention, (6) is the voice coil wound on this, and the first
Figure (b) is a partially enlarged front view of the voice coil bobbin. In the figure, (iota) is the warp thread, (105bl is the warp thread (105cl is the warp thread, and its opposing angle with respect to 105al is 6).
These are two X-shaped weft threads that intersect at an angle of 0 degrees, making a triaxial woven fabric. As the warp and weft yarns, for example, Kepler yarn having a high elastic modulus is used.

Then, the voice coil bobbin (105) vibrates, and this vibration propagates to the diaphragm (7), emitting sound.
The voice coil bobbin (1051) is made of triaxial woven fabric without anisotropy, so the Young's modulus in all directions is the same as shown in Figure 5 (bl).
The non-axisymmetric vibration mode of the voice coil bobbin is suppressed,
Transmission loss from the voice coil bobbin (105) to the diaphragm (7) can be suppressed.

In addition, since the voice coil bobbin (105) is made of triaxial weave fabric, the warp and weft threads are more strongly connected than the conventional 90 degree weave, making it resistant to buckling. Even if the lower end of (+05) hits the pole piece [11], the voice coil bobbin will not buckle (this effect is further enhanced by the use of the Keplerian thread, which has the above-mentioned high elasticity).

In the above embodiment, the warp thread and the weft thread are each made up of one thread, but as shown in other embodiments shown in Fig. 2, each thread is made up of two or more similar threads to form a similar woven fabric. Similar effects and effects can be obtained in both cases.

In each of the above embodiments, the weft and warp intersect at an angle of 60 degrees, but similar effects and effects can be obtained if the intersecting angle is within the range of 40 degrees to 80 degrees.

[Effects of the Invention] As described above, since the voice coil bobbin of the present invention is made of a triaxial woven fabric without anisotropy, there is no transmission loss from the voice coil bobbin to the diaphragm. In addition, since the woven fabric uses Keplerian yarn having a high elastic modulus, it also has the effect of increasing buckling strength in combination with the above-mentioned triaxial weave.

[Brief explanation of the drawing]

Fig. 1 [a] is a perspective view showing a voice coil bobbin for a speaker according to the present invention, Fig. 1 (b) is an enlarged front view of a part thereof, and Fig. 2 shows another embodiment of Fig. 1 (bl). FIG. 3 is a sectional view of the right half of a conventional speaker; FIG. 4(a) is a perspective view of a conventional voice coil bobbin; FIG. Figure 5 (
a) and (b) are comparison diagrams of the elastic modulus of the conventional 90 degree weave and the triaxial weave of the present invention. In the figure, flQ51 is a voice coil bobbin, (105a
) are warp threads, and (105b) and (105c) are weft threads. Figure 05a Figure (a) (a)

Claims (2)

[Claims] (1) Three weaving yarns in which two weft yarns combined in an X shape intersect with one warp yarn at opposing angles ranging from 40 degrees to 80 degrees. Voice coil bobbin for speakers made of shaft-woven fabric. (2) The voice coil bobbin for a speaker according to claim 1, which uses Kepler yarn having a high elastic modulus as each yarn.