JPH08289394A - Speaker - Google Patents

Abstract

PURPOSE: To smooth the flow of air at the rear of a diaphragm to improve the tone quality with respect to a speaker used in various acoustic apparatus. CONSTITUTION: A groove 1b which has 2mm or longer width and 0.5mm or longer depth toward the center is provided at least in one position on the outer peripheral face of a center pole 1a of a lower plate 1 constituting a magnetic circuit. Thus, the flow of air in a space part 10 on the rear side of a dust cap is smoothed to smoothly move the dust cap 9 and a diaphragm 7, and as the result, noise and distortion of the speaker are reduced to improve the tone quality of the speaker.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a speaker used in various audio equipment.

[0002]

2. Description of the Related Art A conventional speaker will be described below with reference to the drawings.

FIG. 7 shows the structure of a conventional speaker in a front view in half cross section. The structure is such that a ring-shaped upper plate 2 is provided between a lower plate 12 having a center pole portion 12a. The magnets 3 are arranged and combined in a laminated state to form a magnetic circuit 4 having an annular magnetic gap 4 with a uniform gap.

A frame 5 is connected to the upper surface of the upper plate 2, and a damper 6 and an outer peripheral portion of a cone-shaped diaphragm 7 are connected to the frame 5, and the inner circumferences of the damper 6 and the diaphragm 7 are connected to each other. The portion is connected to the bobbin portion 8 of the voice coil and supports the voice coil wire ring 8 a so as not to touch the magnetic gap 4.

Further, a dust cap 9 is connected near the center of the diaphragm 7 to prevent dust from entering the magnetic gap 4.

Next, regarding the operation of the speaker, when an electric signal is input to the voice coil wire 8a, the voice coil wire 8a moves in response to a vertical force from the magnetic gap 4, and this force is applied to the voice. The vibrating plate 7 connected to the coil bobbin 8 is driven, and the vibrating plate 7 generates sound on the front surface of the speaker.

[0007]

However, in the above conventional configuration, in order for the speaker to accurately generate sound, the vibration of the diaphragm 7 (including the dust cap 9) is accurately transmitted to the air in the front-rear direction, Moreover, it is ideal that the vibration is transmitted in the front-back direction without obstruction, but in reality, the vibration plate 7
To the rear of the frame 5, damper 6, upper plate 2,
A lower plate 12 is present to prevent free vibration of air behind the diaphragm 7. Particularly, a space 10 surrounded by the dust cap 9, the voice coil bobbin 8 and the center pole 12a is provided behind the dust cap 9. Yes, this space 10 includes a voice coil bobbin 8 and a center pole 12a.
Although it is connected to the rear space of the speaker through a magnetic gap 4 which is a narrow gap with the outer peripheral surface of the speaker, the annular gap of the magnetic gap 4 is usually around 0.2 mm, and acoustic resistance is present in that portion. Due to the presence, the space behind the dust cap 9 substantially exists as a closed space above 20 Hz, which is the reproduction band of the speaker, and the space portion 1 of this portion is present.
The air resistance generated by the volume of 0 and the magnetic gap 4 significantly restricts the movement of the dust cap 9 and the diaphragm 7, which increases the acoustic resistance of the speaker and lowers the sound pressure level in the low frequency range. However, there is a problem that the sound quality is deteriorated and the sound quality is deteriorated.

The present invention solves such conventional problems,
An object of the present invention is to provide a speaker capable of exhibiting excellent performance by smoothing air circulation behind the diaphragm, particularly on the back side of the dust cap.

[0009]

In order to solve the above-mentioned problems, the speaker according to the present invention has a width on at least one of the outer peripheral surface of the center pole portion of the lower plate or the inner peripheral surface of the upper plate which constitutes the magnetic circuit. Of 2 mm or more and a depth of 0.5 mm or more is provided in the vertical direction.

[0010]

[Operation] With this configuration, the air flow in the rear of the diaphragm, especially the back of the dust cap is improved, and noise and distortion are reduced.
A speaker with excellent performance can be obtained.

[0011]

【Example】

(Embodiment 1) Hereinafter, a first embodiment of the present invention will be described with reference to the drawings.

In this embodiment, parts having the same constructions as those of the conventional speaker described with reference to FIG. 6 are designated by the same reference numerals, and detailed description thereof will be omitted.

FIG. 1 is a front view in half section showing the structure of a speaker according to the same embodiment, and FIG. 2 is a plan view of a lower plate used in the speaker according to the same embodiment.

In FIGS. 1 and 2, reference numeral 1 denotes a lower plate having a center pole portion 1a.
Is provided with six vertical grooves 1b having a width of 2 mm and a depth of 1 mm toward the center on the outer peripheral surface of the center pole part 1a, and the lower part including the center pole part 1a having the grooves 1b is provided. By stacking and coupling the ring-shaped magnet 3 and the ring-shaped upper plate 2 on the plate 1, a uniform gap is formed between the upper end of the outer peripheral surface of the center pole portion 1 a and the inner peripheral surface of the upper plate 2. To form a magnetic circuit in which the annular magnetic gap 4 is formed.

Reference numeral 5 is a frame coupled to the upper surface of the magnetic circuit, 8 is a voice coil bobbin having a lower end wound with a voice coil loop 8a fitted in the magnetic gap 4, and 6 is an inner peripheral portion of the voice coil bobbin 8. A damper having an outer peripheral portion connected to the frame 5 and an outer peripheral portion connected to the peripheral edge of the frame 5 and an inner peripheral portion connected to the voice coil bobbin 8. , 9 are coupled to the upper surface of the central portion of the diaphragm 7, and a dust cap 10 for preventing dust from entering the magnetic gap 4 is a space formed on the back surface of the dust cap 9.

The loudspeaker of this embodiment having the above-described structure has the structure in which the center pole portion 1a of the lower plate 1 constituting the magnetic circuit is provided with the six grooves 1b so that the voice coil bobbin 8 and the center pole are formed. The cross-sectional area of the gap between the portions 1a is 1.6 times that in the case where the groove 1b is not provided, and the air flow in the space portion 10 on the back surface of the dust cap is smoothed without impairing the performance of the magnetic circuit. As a result, the speaker of the present embodiment has an acoustic resistance of 0.9 → 0.6, a sound pressure level of 1.0 dB, and a natural sound quality with a middle and low range. It can be secured.

FIG. 3 shows the frequency sound pressure characteristics of the loudspeaker of this embodiment having the above-described structure in comparison with the conventional product, and Table 1 shows various parameter comparison tables. The lower plate 1 provided with the center pole portion 1a of the present embodiment is formed by forging, and the six grooves 1b can be processed by the die at the time of forging, so that the number of processing steps does not increase. Therefore, the cost can be obtained as the conventional product.

[0018]

[Table 1]

(Second Embodiment) A second embodiment of the present invention will be described below with reference to the drawings.

FIG. 4 is a front view in half section showing the structure of the speaker according to the same embodiment, and FIG. 5 is a plan view of an upper plate used in the speaker according to the same embodiment. In this embodiment, the groove 1b provided in the center pole portion 1a of the lower plate 1 in the first embodiment is used.
Is provided on the upper plate. Since the structure other than this is the same as that of the first embodiment, detailed description thereof will be omitted and only different parts will be described.

4 and 5, reference numeral 11 denotes a ring-shaped upper plate, and the inner peripheral surface of the upper plate 11 has six vertical grooves 11a having a width of 2 mm and a depth of 1 mm toward the outer peripheral direction. The groove 11a has the same effect as that of the first embodiment.

Since the upper plate 11 is formed by punching and the six grooves 11a can be processed by the die at the time of punching, there is no increase in the number of working steps, and therefore the cost is also conventional. As it is.

(Embodiment 3) A third embodiment of the present invention will be described below with reference to the drawings.

FIG. 6 is a half sectional front view showing the structure of the speaker according to the present embodiment. In this embodiment, the lower plate 1 provided with the groove 1b in the center pole portion 1a used in the first embodiment, and the above-mentioned embodiment. The upper plate 11 having the groove 11a provided on the inner peripheral surface used in Example 2 is also used. By assembling the groove 1b of the lower plate 1 and the groove 11a of the upper plate 11 by a jig, The cross-sectional area between the coil bobbin 8 and the center pole portion 1a and between the upper plate 11 is increased, and a larger effect than that of the above-described first and second embodiments is obtained, and the air flow in the space portion 10 on the back surface of the dust cap is increased. It is possible to obtain a speaker having excellent performance in which noise and distortion are reduced more smoothly.

[0025]

As described above, the speaker according to the present invention is
A vertical groove having a width of 2 mm or more and a depth of 0.5 mm or more is provided on at least one of the outer peripheral surface of the center pole portion of the lower plate and the inner peripheral surface of the upper plate forming the magnetic circuit. As a result, this groove serves as an air flow path to smooth the air flow in the space behind the dust cap, and a speaker with excellent performance in which noise and distortion are reduced can be realized without increasing the cost.

[Brief description of drawings]

FIG. 1 is a half cross-sectional front view showing the configuration of a speaker according to a first embodiment of the present invention.

FIG. 2 is a plan view of a lower plate used in the same embodiment.

FIG. 3A is a frequency sound pressure characteristic diagram showing the characteristics of the speaker according to the embodiment. FIG. 3B is a frequency sound pressure characteristic diagram showing the characteristics of the conventional speaker for comparison.

FIG. 4 is a half sectional front view showing the configuration of a speaker according to a second embodiment of the present invention.

FIG. 5 is a plan view of an upper plate used in the same embodiment.

FIG. 6 is a half sectional front view showing a configuration of a speaker according to a third embodiment of the present invention.

FIG. 7 is a half sectional front view showing the configuration of a conventional speaker.

[Explanation of symbols]

 1 Lower Plate 1a Center Pole Part 1b Groove 2 Upper Plate 3 Magnet 4 Magnetic Gap 5 Frame 6 Damper 7 Vibration Plate 8 Voice Coil Bobbin Part 8a Voice Coil Wire Ring 9 Dust Cap 10 Space behind the Dust Cap 11 Upper Plate 11a Groove 12 Lower plate 12a Center pole part

Claims (3)

[Claims] 1. The width is 2 at least at one or more locations on the outer peripheral surface.
A lower plate having a center pole portion having a vertical groove of 0.5 mm or more and having a depth of 0.5 mm or more toward the center, a ring-shaped magnet, and a ring-shaped upper plate are laminated and coupled. A magnetic circuit in which a magnetic gap is formed, a frame coupled to the upper surface of the magnetic circuit, and a diaphragm coupled to the outer periphery of the frame and a voice coil centered in the magnetic gap. Speaker. 2. The width is 2 at least at at least one location on the inner peripheral surface.
A ring-shaped upper plate provided with a vertical groove having a depth of 0.5 mm or more and a depth of 0.5 mm or more toward the outer peripheral direction, a ring-shaped magnet, and a lower plate provided with a center pole portion are laminated and coupled. A magnetic circuit in which a magnetic gap is formed, a frame coupled to the upper surface of the magnetic circuit, and a diaphragm coupled to the outer periphery of the frame and a voice coil centered in the magnetic gap. Speaker. 3. The width is 2 at least at one place on the inner peripheral surface.
A ring-shaped upper plate provided with a vertical groove having a depth of 0.5 mm or more and a depth of 0.5 mm or more toward the outer periphery, a ring-shaped magnet, and a width of 2 mm or more in at least one location on the outer peripheral surface and a center direction. A magnetic circuit in which a magnetic gap is formed by stacking and combining a lower plate having a center pole portion having a vertical groove with a depth of 0.5 mm or more toward the upper surface of the magnetic circuit. A speaker comprising a frame and a diaphragm having an outer peripheral portion coupled to the peripheral edge of the frame and a voice coil centered in the magnetic gap.