JPS5937799A - Dynamic electroacoustic transducer - Google Patents

Abstract

PURPOSE:To realize cost reduction and high performance by using a permanent magnet which is made of Fe-Cr-Co alloy and drawn partially into a work plate body extending outward radially from a center and has a radial anisotropy in the plate surface direction. CONSTITUTION:The permanent magnet 1 made of the Fe-Cr-Co alloy consists of a cylinder part 1a which has a diameter nearly equal to the external diameter of the flange part 2b of a yoke 2 and a diameter reduction part 1b formed by bending and reducing one end part of the cylinder part 1a in diameter. Namely, part of it consists of the work plate body drawn outward radially from the center part. Then, the inward end surface of the diameter reduction part 1b is an N pole and the lower end surface of the cyliner part 1a is an S pole, obtaining the radial magnetic anisotropy in the plate surface direction of the work plate body. Consequently, the modified permanent magnet which has large coercive force, residual magnetic flux density, and maximum energy product is realized, so the magnetic flux density of a gap part 3 is increased greatly.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an electro-acoustic transducer of the fJ type used, for example, in a telephone handset, and particularly relates to improvements in the permanent magnetic field that constitutes the magnetic circuit.

The magnetic rotation r8 in d3 of the conventional electrodynamic electroacoustic transducer is
As is well known, there are two types: the inner pot type, which has a permanent magnet of the same name in the center, and the outer type, which has a ring-shaped permanent magnet on the outer periphery. In any type of magnetic circuit, conventionally, two or three or more yokes, including a yoke called a center 1ζ-ru, are drawn together with a permanent magnet, and the permanent magnet h11 Two people are placed so that the generated energy is efficiently concentrated in the gap.

However, this type of conventional magnetic V8 has a large number of joint-sized parts, and it is difficult to assemble the H1 and 10 losses at the joints ("-1 step"). This disadvantage is particularly noticeable in the case of relatively fl!-l strike electroacoustic transducers, such as those used in the handsets of λ-phone telephones.

Reduce the number of magnetic circuit parts! 34-For plastic deformation-L-
It has been proposed to use a 5V permanent magnet shaped like a magnetic circuit formed by a magnetic circuit, but conventional plastic IJ
1. i, large holding force 1 required for electrodynamic electroacoustic transducer] (residual flux density B1゛,
Maximum” - Characteristics of Count Nergie etc. 1! A permanent magnet for a strong magnetic circuit that vortexes I is 1q and l-9 This invention is
- The WQ point has been improved by two times compared to the conventional WQ point mentioned above, and its purpose is to create a strong deformed shape that is easy to plastic work and has a sufficiently large holding force Ha and residual magnetic flux @ degree B r. By using permanent magnets, we can reduce the number of components in the magnetic circuit and provide an inexpensive and high-performance electrodynamic electroacoustic transducer using a magnetic circuit that can satisfy the required magnetic properties. Particularly, in order to achieve the above object, the present invention provides a permanent magnet 6 of a magnetic circuit made of an Fe-0r-Co alloy,
A part of the plate is formed into a continuous plate extending outward from the central space, and has a continuous magnetic anisotropy along the direction of the surface of the plate. Cover up what happened.

Hereinafter, embodiments of the present invention will be explained in detail based on the drawings.

FIG. 1 is a sectional view of an electrodynamic electroacoustic transducer according to the present invention. The magnetic circuit included in this electrodynamic electroacoustic transducer is composed of two parts: a permanent magnet 1 and m-ridges 2. A voice coil 5 attached to a dome-shaped diaphragm 4 is disposed within an annular gap 3 in this magnetic circuit. A wear-proof ring 6 made of a non-magnetic material is attached to the lower side of the cavity 3, and a protective plate 7 is attached to the front side of the diaphragm 4 with a spacer 8. is,
Furthermore, the entire evaporation circuit is housed in a case 9, and an ise piece 10 is attached to the front side.

Perpetual Mj? The 11 air circuits formed by the il yoke 2 will be explained in detail. The yoke 2 consists of a cylindrical portion 2a having a straight line, and a flange portion 2I+ whose one end is bent outward and expanded. Eternal 1N ('il, IIHI2O
3. Approximately equal to the outside i of the flange portion 2b (the cylindrical portion 1a of yen and the reduced diameter portion 11 formed by bending and reducing the diameter of one end of the cylindrical portion 1a)
It depends on where you are. In other words, the permanent 1j record 11 is a part of it that extends outward from the central space in a finished form.]
゛It consists of a plate. MarlJ, this eternity 1i7'i1
In this case, the inner end surface on the reduced diameter part 1]) side becomes the N pole, and the cylindrical part 1a
The lower end surface of the side is S (snoring and 13-), especially the first riveting point is a permanent magnet r11 as shown by the arrow N1 in Figure 2.
is the fact that the processed plate having the above shape has a magnetic anisotropy in the plate surface direction of 1/1. As a result, the holding force Hc, the residual m flux density 3r and J, An irregularly shaped permanent magnet 1 with a large maximum energy product has been realized. for,
The magnetic flux density in the air gap 3 can always be increased by J[.

Next, the composition J3 of the irregularly shaped permanent magnet 1, which is the main part of the present invention, and the manufacturing method thereof will be explained. ~30%, Co5~37%, and the remainder consists essentially of pe, with 1-i and 7r as necessary.
, N+ , V13i, etc., containing 0.1 to 8% of trace elements such as V13i (%
is based on weight).

To manufacture the above permanent magnet 1, first the above-mentioned Fe
- Forming a straight pipe made of a Cr-Co alloy. This straight pipe can be formed by drawing or extrusion using the above-mentioned plastic workability of the alloy, or by forming a flat plate once. and bending this flat plate to form a tube;
A method is used in which both ends are welded, for example, by TIG welding. Next, the obtained straight tube is heat-treated while applying a magnetic field along its central axis direction. The heat treatment conditions were l:e −
The composition of the Or -Co-based alloy is different, but for example, after heat treatment at 670-720°C for about 1 hour, it is heated at 10-90°C for 7 hours. (・600
Cool to −620° C. and then rapidly cool. Magnetic field strength I
J, generally 16000-400000△'ml'N
Ii is appropriate. For such magnetic field processing, J, Fc-
Plastic of Cr-Qo alloy t! 1lIn The I property is reduced by 4 degrees, but it is not enough to prevent the subsequent irregular shape processing.

After the magnetic field heat treatment, one end of the straight tube is subjected to a diameter reduction process to form a diameter reduction part 11) in a certain shape as shown in the figure. This addition ]゛ is, for example, cold IJI+ ]' +1 j
It is appropriate to use a cold or 400 to 500° C.: culm degree 0 drying process using a warm or hot spatula tightening machine. By repeating this addition, the reduced diameter part 1
The ratio of the diameter of t+ to the diameter of the straight pipe material is 1'4.-5 times the processing rate.

Furthermore, the above-mentioned -
The fj5 obtained from the culm is given by the magnetic circumference jj 411 if
It is possible to significantly improve the comfortability while maintaining the temperature. The aging treatment can be achieved, for example, by subjecting the material to heat treatment for 10 to 30 hours while gradually decreasing the temperature range 11 in the temperature range of 500 to 620°C. Plastic deformation of Fe-0r-Co alloy material J,
Since the properties are significantly lost, the above-mentioned shape processing must be completed before the aging heat treatment.

By the manufacturing method described above, le Cr Q.

A permanent magnet 1 for a magnetic circuit of an irregular shape that makes the most of the excellent plastic workability and magnetic properties of the alloy is obtained.

By adding J to this permanent magnet 1, it is possible to construct a magnetic circuit that can satisfy the various mechanical characteristics required for an electrodynamic electroacoustic transducer using any combination of one yoke 2. .

In the embodiment shown in the figure, the permanent magnet 1 has a vz-shape formed by a cylindrical part 1a, a reduced diameter part 1b, etc.; 2 J, sea urchin 1
A magnetic circuit equivalent to the above can be constructed with two parts by combining a cylindrical part 2a with a cylindrical part 2a and a flange part 2b formed by expanding the diameter of this part with a yoke. In addition to being able to describe the shapes and compositions of the gods. be able to.

As explained in detail above, in the electrodynamic electroacoustic transducer according to the present invention, it is possible to construct a magnetic circuit with good performance with a small number of parts. can be provided at low cost.

[Brief explanation of the drawing]

Fig. 1 is a sectional view of an electrodynamic 11 electroacoustic transducer according to an embodiment of the present invention;
It is a partially cutaway perspective view of a stone. 1...Permanent magnet 1a river part 11)...Reduced diameter part 2...Yoke 2a...Cylinder part 21)...Flange part 3... Gap 4...Vibration plate 5...Voice Ni''il

Claims (1)

[Claims] (1) The voice coil attached to the diaphragm is a permanent magnetic 7
In an electrodynamic electroacoustic transducer disposed in an annular gap in a magnetic circuit including 1; the permanent magnet is
It is made of a Fe-Qr'-Go alloy, and a part of it extends radially outward from the center space to form a single plate, and the radial magnetic anisotropy along the surface direction of the processed plate is adjusted to the right. An electrodynamic electroacoustic transducer characterized by: