JP3365095B2 - Speaker - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a loudspeaker used for various audio equipment. 2. Description of the Related Art A conventional speaker will be described below with reference to the drawings. FIG. 5 is a half sectional view showing the structure of a conventional speaker. A ring-shaped magnet 3 is arranged between a lower plate 1 having a center pole and a ring-shaped upper plate 2 and laminated. The magnetic circuit is formed in such a manner that an annular magnetic gap 4 having a uniform gap is formed between the center pole and the upper plate 2. A frame 5 is provided on the upper surface of the magnetic circuit.
The outer periphery of the damper 6 and the cone-shaped diaphragm 7 are connected to the frame 5, and the inner periphery of these components is connected to the voice coil 8. Support the magnetic gap 4 so as not to touch it. Further, a dust cap 10 is connected to the upper surface near the center of the diaphragm 7 to prevent dust from entering the magnetic gap 4. [0005] The conventional loudspeaker configured as above is
When an electric signal is input to the wire 9 of the voice coil 8, the voice coil 8 moves by receiving a force from the magnetic gap 4, and this force moves the diaphragm 7 coupled to the voice coil 8,
The diaphragm 7 was configured to generate sound on the front of the speaker. However, in the above-mentioned conventional speaker, the driving force of the voice coil 8 is controlled by the wire 9 of the voice coil 8 fitted in the magnetic gap 4 of the magnetic circuit.
(L) × magnetic flux density (Bg) of the magnetic gap 4 × current, and it is ideal that the driving force L × Bg should take a constant value with respect to the movement of the speaker. If this fluctuates, the sound generated by the speaker will be distorted. Accordingly, in the conventional speaker, as shown in FIG. 6, since the length B of the loop 9 of the voice coil 8 is substantially the same as the length A of the magnetic gap 4, the (A-
For an amplitude of B) / 2 or more, a part of the voice coil 8 protrudes from the magnetic gap 4, and L × Bg changes to generate distortion. As one of the methods for reducing the occurrence of this distortion, there is a method of setting A to be sufficiently large with respect to B. However, this method is effective in reducing the distortion as the thickness of the upper plate 2 increases. The thickness of the upper plate 2 increases as the performance of low distortion is improved, and the thickness and weight of the upper plate 2 increase.
It was not suitable for applications requiring light weight. [0008] An object of the present invention is to solve such a conventional problem and to provide a thin and lightweight speaker with low distortion. In order to solve this problem, a speaker according to the present invention comprises a lower plate having a center pole portion, a ring-shaped magnet, and at least one at one end of an inner peripheral surface. A configuration using a magnetic circuit in which a magnetic gap is formed by laminating two ring-shaped upper plates, each of which has been subjected to C chamfering or R processing with a thickness of 0.5 mm or more, is formed, and the inner periphery of the upper plate is formed. Surface
The other end is projected in the vertical direction . According to this configuration, the thickness of the upper plate can be made smaller than that of a method of increasing the thickness of the upper plate in order to make the amplitude margin of the voice coil the same size.
A low-distortion speaker with reduced weight can be provided. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Before describing an embodiment of the present invention,
Example of improvement up to the embodiment will be described with reference to the drawings.
I do. FIG. 1 is a front half sectional view showing a configuration of a speaker according to an improved example , in which a lower plate 1A having a center pole, a ring-shaped magnet 3A, and two ring-shaped upper plates 11A and 11B are stacked. To form a magnetic circuit in which an annular magnetic gap 4 having a uniform gap is formed between the outer peripheral portion of the center pole of the lower plate 1A and the inner peripheral surfaces of the two ring-shaped upper plates 11A and 11B. are doing. Further, the two ring-shaped upper plate 11A, among 11B, C chamfering processing is given to one end of the inner peripheral surface of the lower side of the upper plate 11B, in the improved embodiment the C chamfer Is 2 mm, the material thickness is 7 mm, the material thickness of the upper plate 11A on the upper side is 5 mm, and the total of the upper plates 11A and 11B is 12 mm. Reference numeral 8 denotes a voice coil fitted into the magnetic gap 4, and reference numeral 9 denotes a wire wound around the voice coil 8. In the present improved example , the length of the wire 9 is 7 mm.
And Reference numeral 5 denotes a frame coupled to the upper surface of the magnetic circuit, 6 denotes a damper for supporting the voice coil 8, 7 is coupled around the voice coil 8, and has an outer peripheral portion on the periphery of the frame 5. Combined diaphragm, 10
Is a dust cap connected to the upper surface of the central part of the diaphragm 7. The length of the magnetic gap 4 of the loudspeaker of the present embodiment thus constructed is A2, the dimension of the C chamfered portion of the upper plate 11B is C, and the wire loop 9 of the voice coil 8 is formed.
If the length of B is B and the amplitude margin is D1, D1 = A2 / 2
+ C (B = A2 + C). The amplitude margin D2 of the conventional loudspeaker described with reference to FIG. 5 is D2 = (AB).
/ 2, and if the amplitude margins of the speaker of the present improvement example and the conventional speaker are set to the same value, D1 = D2, and the difference in thickness of the magnetic gap portion at this time is A2 × 2 + CA = (2B−
2C) + C− (2B + C) = − 2C, and the loudspeaker of this improved example can reduce the thickness of the magnetic gap portion for securing the same amplitude margin as the conventional loudspeaker by 2C. ( Embodiment 1 ) An embodiment of the present invention will be described below with reference to the drawings.
You. In this embodiment, the weight of the speaker of the above-described improved example is reduced.
It is intended to reduce the thickness. FIG. 2 is a front half sectional view showing the structure of the speaker according to the embodiment. In this embodiment, the upper plate 11B of the improved example described with reference to FIG. Since the other parts are the same as those of the improved example , the same parts are denoted by the same reference numerals, detailed description thereof will be omitted, and only different parts will be described. In FIG. 2, reference numeral 11C denotes an upper plate. One end of the inner peripheral surface of the upper plate 11C is subjected to a C-chamfering process, and the other end is formed to have a shape protruding in the vertical direction. The material thickness is 3.2 mm with the C chamfered portion being 2 mm, the thickness of the inner peripheral surface excluding the C chamfered portion is 5 mm, and the thickness of the magnetic gap on the inner peripheral surface of the upper plates 11A and 11C is improved as described above. 12m same as the example
m. FIGS. 3 (a) and 3 (b) are cross-sectional views of the main part of the speaker of FIG.
The thickness of the magnetic gap can be reduced by 2C in the same manner as in the above-described improved example, and the thickness of the main body of the upper plate 11C is reduced by protruding (7 mm-3.2 m).
m = 3.8 mm) Further, the speaker can be made thinner. FIG. 4 shows the frequency characteristics of the loudspeaker according to the present embodiment in comparison with the same characteristics of the conventional loudspeaker.
It was confirmed that the third harmonic distortion in the low frequency range was reduced to about 1/2. As described above, the speaker according to the present invention has the following features.
Since the magnetic gap length can be reduced and a sufficient amplitude margin can be obtained, a thin and lightweight speaker with low distortion can be provided.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a front half sectional view showing a configuration of a speaker according to an improvement example leading to the present invention. FIG. 2 is a front half sectional view showing a configuration of a speaker according to an embodiment of the present invention. 3 is an enlarged cross-sectional view of the main part. FIG. 4 is a frequency characteristic diagram comparing frequency characteristics of the speaker of the present invention and a conventional speaker. FIG. 5 is a front half cross-sectional view showing a configuration of the conventional speaker. 1A Lower plate 3A Magnet 4 Magnetic gap 5 Frame 6 Damper 7 Vibration plate 8 Voice coil 9 Voice coil wire ring 10 Dust cap 11A Upper plate 11B Beveled upper plate 11C Upper plate with vertical projections

Claims (1)

(57) [Claims 1] A lower plate having a center pole portion, a ring-shaped magnet, and a C-chamfer of at least one end of an inner peripheral surface of 0.5 mm or more, or R processing. A magnetic circuit in which a magnetic gap is formed by laminating and coupling two ring-shaped upper plates, a frame coupled to an upper surface of the magnetic circuit, and a voice coil that fits in the magnetic gap. A loudspeaker whose outer peripheral portion is formed of a diaphragm coupled to a peripheral edge of the frame , wherein one end of the inner peripheral surface has a C of 0.5 mm or more.
On the above upper plate with chamfer or R processing
A speaker in which the other end of the inner peripheral surface protrudes vertically.