JP2556162Y2 - Magnetic shield type horn speaker - Google Patents

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a magnetically shielded horn speaker, and more particularly, to a rear-emission horn speaker suitable for audiovisual equipment. [Outline of the invention] To prevent magnetic flux leakage, a shield case is put on the outer surface of the yoke constituting the magnetic circuit via a spacer, and the sound path of the magnetic circuit is connected to the horn through the spacer and the shield case. Magnetically shielded horn speaker. 2. Description of the Related Art A conventional horn speaker has an equalizer formed on a center pole 1 constituting a magnetic circuit and a sound path 2 as shown in FIG. There is a dome-shaped diaphragm 3 on the entrance side, and a yoke 4
The horn 5 is attached to the outer surface of the
The diaphragm 3 is covered by a cover 6 attached to a magnetic circuit. [Problems to be Solved by the Invention] In the horn speaker as described above, if a part of the magnetic flux flowing through the magnetic circuit leaks to the outside and there is a display typified by a television receiver or the like nearby, the leaked magnetic flux And have adverse effects such as color misregistration. Means for Solving the Problems In order to solve the above-mentioned problems, the present invention provides a rear-emission horn loudspeaker having an external magnet type magnetic circuit, which is mounted on the outer surface of a yoke and emits radiation. A sound hole with an extended inner surface of the inner surface of the sound path whose cross-sectional area is enlarged in the direction, and a sound hole that extends over the sound hole of the spacer and covers the spacer and the magnetic circuit. A shield case and a horn having a sound path communicating with a sound hole formed in the shield case are provided, and a configuration is adopted in which leakage magnetic flux of a magnetic circuit is prevented from leaking by the shield case. . An embodiment of the present invention will be described below with reference to FIG.
First, in this figure, reference numeral 10 denotes a plate 11, a magnet 1
2, yoke 13, center pole 14 with equalizer function
The rear end face of the center pole 14 has a partially spherical shape, and a dome-shaped diaphragm 21 is arranged along the rear end face. The diaphragm 21 has a peripheral edge fixed to the plate 11 via an edge 22 by a gasket 23.
Is wound around the bobbin 25 and positioned in the magnetic gap. The center pole 14 constituting the magnetic circuit 10 has a sound path 31 formed along the axis thereof, and the sound path 31 has a cross-sectional area which is continuously enlarged in the direction of sound wave radiation. I have. Further, the plate 11 side of the magnetic circuit 10 is covered with a cover 41 to protect the diaphragm 21, and a sound hole 42 having an extension of the sound path 31 is provided on the opposite side to the plate 11, in other words, on the yoke 13 side.
The spacer 43 that is pierced is overlaid, this spacer
A shield case 44 is placed over the plate 43 and covers the yoke 13 of the magnetic circuit 10 from the plate 11, and the periphery thereof is fixed to the plate 11. The sound hole 44 connected to the sound hole 42 is also provided in the shield case 44.
The sound hole 44a is provided with an external thread portion 44b. The female screw portion 52 formed on the base portion 51 of the horn 50 is screwed to the male screw portion 44b, and the horn 50 and the driver unit are connected. Therefore, the magnetic flux generated in the magnetic circuit 10
Even if it leaks outside through 43, a loop is formed that reaches the plate 11 via the shield case 44, so that no external leak occurs. Even if the magnetic flux leaks from the spacer 43 due to a failure in the connection portion or the like, the magnetic flux is immediately drawn into the shield case 44, so that the magnetic flux does not spread outside. [Other Embodiments] Further, instead of the spacer 43 shown in the first embodiment, a repulsion magnet 45 having a polarity opposite to that of the magnet 12 is arranged as shown in FIG. The magnetic flux leaking out is canceled by the magnetic flux of the repulsion magnet 45 and is sealed inside by the shield case 44. This repulsion magnet 45 also has a sound path 31, a sound hole 42,
A sound path 53 that expands in the radial direction is formed in accordance with the increase in the cross-sectional area of 44a. The horn 50 has a base 51 as a flange, and is fixed to the shield case 44 by screws 54. [Effects of the Invention] As is apparent from the above description, since the present invention has the above-described configuration, the magnetic flux leaking from the magnetic circuit is captured by the shield case, and even if the magnetic flux is arranged close to the display, the color shift occurs. There is no trouble such as.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a sectional view of a principal part of a magnetically shielded horn speaker according to the present invention, FIG. 2 is a sectional view of a principal part of another embodiment, and FIG. It is. 10 ... magnetic circuit, 11 ... plate, 12 ... magnet,
13 ... Yoke, 14 ... Center pole 21 ... Diaphragm, 22 ... Edge, 23 ... Gasket 31 ... Sound track 41 ... Cover, 42 ... Sound hole, 43 ... Spacer, 44 ... Shield Case, 44a: Sound hole, 44b: Male thread 50: Horn, 51: Base, 52: Female thread.

Claims (1)

(57) [Rules for requesting registration of utility model] In a rear-emission horn speaker having an outer-magnet-type magnetic circuit, a sound hole that is attached to an outer surface of a yoke and has an extended inner surface of an inner surface of a sound path whose cross-sectional area is enlarged in a radiation direction is formed. A shield case covering the magnetic circuit with the spacer, and having a sound hole extending from the inner surface of the sound hole of the spacer, and a horn having a sound path in communication with the sound hole formed in the shield case. A magnetically shielded horn speaker characterized in that a leakage flux of a magnetic circuit is prevented by a shield case.