JPS6237599B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] This invention relates to a coil that is movable axially in an annular gap between an inner pole piece and an outer pole piece that are coupled to each pole of a magnet. An electrodynamic device that is equipped with a diaphragm and is composed of a magnet part, a coil separated from the magnet part, and a diaphragm part, and the magnet part is integrated with the container unit having the guide pin by attaching a unit consisting of a magnetic pole piece and a magnet to the guide pin. The present invention relates to a method of manufacturing a type transducer.

[Prior Art] This type of electrodynamic transducer operates as a microphone or speaker by converting sound waves into electrical signals or vice versa. The electrodynamic transducer of the invention is particularly intended for use in telephone technology. Therefore, it must have extremely high sensitivity and be mass-produced at low cost. Magnet materials with high residual magnetization, that is, materials that contain more energy and are more expensive than the ferrite magnets used, but materials that provide significantly higher sensitivity than the ferrite magnets, that is, reinforced earth magnets.
By using cobalt compounds, so-called Re-Co magnets, it is possible to reduce the volume of the magnet to compensate for the increased cost.

In conventional electrodynamic transducers, the diaphragm was always pre-molded prior to assembling the transducer. Additionally, many previously known transducers are assembled from multiple parts that include a critical set of tolerances. This makes manufacturing such transducers very difficult and results in a number of unacceptable products. Furthermore, while all conventional transducers simply clamp the preformed diaphragm to a support ring or the like, such a process is not suitable for small transducers due to the risk of eccentricity. Cannot be hired.

Problems to be Solved by the Invention The object of the invention is to provide a method for manufacturing an electrodynamic transducer with improved sensitivity and which can be manufactured almost completely automatically.

Means for Solving the Problem This problem is solved by the use of a heat deformable support ring on one side with an inner cylindrical wall having the same diameter in a first position as the outer cylindrical wall of the outer pole piece. A flat diaphragm material is adhered with one major surface thereof facing the support ring, and in a second position a coil is adhered to the diaphragm material coaxial with the support ring and of the same diameter as the annular gap between the two pole pieces. depositing a heat-activated adhesive on the one major surface of the diaphragm material and at least one of the coils in a region and directing a heat-releasing diaphragm former coaxially to the surface of the diaphragm material opposite the support ring in a third location; At the same time, pressurized air pressure is applied to the diaphragm material surface on the opposite side to form a diaphragm so that the diaphragm material is bonded to the diaphragm forming tool, and a cylindrical bonding surface having the same outer diameter as the outer magnetic pole piece is formed. This is achieved by a method of manufacturing an electrodynamic transducer in which a coil supported on a guide mold having a diaphragm is crimped onto a coil bonding area of a diaphragm.

The transducer manufactured by the method of the present invention as described above can center the coil in the annular gap very accurately, so the annular gap can be made very narrow, and the loss in the magnetic circuit is small. Since the sensitivity increases, the sensitivity is improved. The very precise centering of the coil in the annular cavity described above is achieved by fixing the diaphragm to a support ring before molding the diaphragm and fixing it to the coil, and the support ring, which is connected to the coil via the diaphragm, This can be achieved by very precise centering with respect to the annular gap between the poles by the coupling of the outer cylindrical wall of the pole piece with the cylindrical wall of the support ring.

Additionally, conventional electrodynamic transducers require the terminals of the coil or the feed line to be drawn through holes in the surrounding enclosure. Such a process itself is not easily compatible with automated production lines.

According to one embodiment of the method of the invention, in a step prior to the third stage of fabricating the coil diaphragm part, the coil mounted on the guide mold is connected to the coil terminal also mounted on the guide mold. The connection is completed by connecting the conductors and in the third position the coil terminals are secured to the support ring by pushing their ends into holes in the support ring.

In another embodiment, which can further automate the process, the connection between the coil terminal and the coil conductor is facilitated by mounting the coil terminal on a guided movable part. This movable part is temporarily movable so that it can be dipped into solder for connection prior to securing the terminal to the support ring in the third position.

The coil feed line can be easily installed by simply fitting it into the groove in the support ring. These grooves are then sealed by suitably covering the coil feed lines. For example, the container portion surrounding the magnet device is provided with a protrusion facing the groove.

The desired frequency characteristics are imparted to the electrodynamic transducer by a suitable acoustic resistance or acoustic filter consisting of a hole connecting the space between the diaphragm and the magnet with the space on the opposite side of the magnet's diaphragm. These pores are filled with a suitable porous filter material. If this filter material were not used, the holes would have to be made very small and manufacturing would be very difficult.

West German Patent Publication DE-AS2206093 and DE
- In the device described in OS 2322475, an annular gap of small cross-sectional area is provided, which corresponds to the above-mentioned acoustic resistance. By means of precisely constructed parts and precise manual centering, the projection of the container can be fitted into the bore of the support ring, so that the cross-sectional area of the cavity can be made sufficiently small.
The pedestal has an auxiliary centering effect when the protrusion is inserted into the hole of the support ring.

However, acoustic resistance holes in the form of cavities of annular or similar shape have the disadvantage that the equivalent self-induction tolerances are undesirably high. The ideal cross-section of the holes is circular, but since sufficiently small holes are very difficult to manufacture, in one embodiment of the method according to the invention the acoustic resistance due to these holes is an integral part of the container unit. It is constructed by fitting pin-like projections with approximately circular cross-section into a corresponding number of square-cross-section holes in the support ring.

[Embodiments] The above-mentioned and other objects and features of the present invention will become clear from the following description of embodiments with reference to the accompanying drawings.

FIG. 1 schematically shows the magnet portion of one embodiment of the electrodynamic transducer of the present invention, and
Figures 1 and 1B show cross-sectional views along lines A--A and B--B in FIG. 1, respectively. The illustrated magnet part essentially consists of a magnet unit consisting of pole pieces 3, 4, a magnet 5, and a container part 1.

As shown in FIGS. 1A and 1B, the container part 1 is provided with a guide pin 2 in the center. This guide pin 2 has an outer magnetic pole piece 3, an inner magnetic pole piece 4, and a magnet 5.
The magnet unit is inserted into a hole provided in the magnet unit to support them. A permanent magnet 5 of a material with high remanence magnetization, for example Re-Co (rare earth, cobalt compound), is sandwiched between the outer pole piece 3 and the inner pole piece 4. A narrow annular gap 6 is formed between the outer pole piece 3 and the inner pole piece 4, which is exaggerated and drawn wider in the figure for clarity. The annular gap 6 can be uniform and very narrow over the entire circumference, since the outer pole piece 3 and the inner pole piece 4 can be mounted very precisely concentrically on the guide pin 2. The container part 1 is provided with two holes 7 for the coil terminals 8 shown in FIGS. 2B and 3B. The outer pole piece 3 is further stabilized in relative position by abutting the outer cylindrical wall surface 12 against the inwardly facing cylindrical wall portion 26 of the container part 1. The container part 1 also has a projection 9 forming part of the acoustic resistance. A magnet unit consisting of an outer magnetic pole piece 3, an inner magnetic pole piece 4, and a magnet 5 is a guide pin 2.
The concentric position is maintained by the guide pin 2 by deforming the outer end 18 of the guide pin 2 as shown. The container part 1 also comprises an outer part 27, the inner surface of which is provided with a support ring 10, which will be described below.
(See Figure 2).

FIG. 2 shows the coil diaphragm portion of the electrodynamic transducer, and FIGS. 2A and 2B show cross-sectional views taken along line A--A and line B--B of FIG. 2, respectively. The coil-diaphragm section comprises a support ring 10 on which is fixed a diaphragm 13 with a coil 15 connected to the terminal 8.

As shown in FIGS. 2A and 2B, the support ring 10 has an inner cylindrical wall surface 11 of the same diameter as the outer cylindrical wall surface 12 of the outer pole piece 3 (see FIG. 1A). The diaphragm 13 is peripherally fixed to the upper edge 14 of the support ring 10 by ultrasonic welding, adhesive, etc. such that the coil 15 is exactly concentric with the cylindrical surface 11 of the support ring 10. coil 1
The two feeder wires 16 of No. 5 are passed through the grooves 23 provided in the support ring 10 to the coil terminals 8 as shown in the figure.
is connected to. The coil terminal 8 is attached to the support ring 1
It is mounted in a hole 28 provided at 0. The coil 15 has the same diameter as the annular gap 6 between the pole pieces, but its thickness is slightly less than the width of the gap 6, so that the coil 15 is movable axially within the gap 6. The support ring 10 also has a hole 17 that communicates between the diaphragm 13 of the support ring 10 and the opposite side thereof in a portion extending to the peripheral edge where the diaphragm 13 of the support ring 10 is attached (FIGS. 3A to 3C). shown in the figure only). Additionally, the support ring 10 includes an inwardly projecting portion 34, as will be described below in conjunction with FIG.

3 shows the completed electrodynamic transducer assembled from the two parts and retaining ring 20 shown in FIGS. 1 and 2, and FIGS. 3A and 3B respectively. Figure 3 shows a cross-sectional view along line A-A and line B-B of the figure.

As shown in FIGS. 3A and 3B, the coil terminal 8 is inserted into the hole 7 of the container part 1. The inner cylindrical wall 11 of the support ring 10 joins with the outer cylindrical wall 12 of the outer pole piece 3, so that the coil 15 is precisely centered in the narrow annular gap 6 between the outer pole piece 3 and the inner pole piece 5. be located. Furthermore, the protrusion 9 is positioned precisely centered in the bore 17, thereby creating a very narrow bore 19 which forms an acoustic resistance or filter. This is shown in detail in Figure 3C. Finally, most transducers are covered by a retaining ring 20 which protects the diaphragm 13 and serves to hold the two parts together. The outer part 27 of the container part 1 is somewhat elastic and is connected to the support ring 10. The support ring 10 also includes an inwardly projecting portion 34 that extends between the two
The outer pole piece 3 is locked in such a way as to limit and define the mutual axial position of the individual parts, namely the magnet part and the coil diaphragm part.

As shown in FIG. 3C, which is an enlarged cross-sectional view taken along the line C--C of FIG. 3A, the container portion 1
The pin-like protrusion 9, which is part of the holder, is of substantially circular cross-section and its lower part is conical for stability. The use of such protrusions 9 as acoustic resistors or filters is already known;
In this example, the protrusion 9 is inserted into a square hole 17 in order to obtain a hole 19 which corresponds to a small cylindrical hole with a very precisely determined self-induction. This structure facilitates reproducibility on automated production lines. As an alternative construction, it is conceivable to insert a pin-shaped protrusion with a square cross section into a circular hole. However, the resulting pores are in the form of elongated voids rather than circular pores. Another possibility is to insert a pin with a circular cross section into a triangular hole. However, a structure consisting of a pin-shaped protrusion with a circular cross section and a square hole is preferred.

4A and 4B illustrate the tools used to fabricate the coil diaphragm portion of the transducer. This coil diaphragm section was shown in FIG. 2B and is shown again in FIG. 4C to clarify how the tool is used.

First, a flat heat-deformable diaphragm material is secured to the peripheral edge 14 of the support ring 10 in a first position by gluing, welding or other means. It should be noted that in this state, the diaphragm 13 has not yet been molded into the shape shown.

A separately manufactured coil 15 is mounted on a guide mold 21 shown in FIG. 4A, the movable portion 29 of which holds the coil terminal 8 in the desired position (level). That is, in the initial position the coil conductor 16 is connected to the coil terminal 8, in the raised position (or in the lowered position) the connection is immersed in solder, and finally the hole 28 of the support ring 10 is connected as described below. is moved to a third position of a predetermined level for insertion. The guide mold 21 has a cylindrical coupling surface 22 of the same outer diameter as the outer pole piece 3 .

In the second position, the sheet of diaphragm material, which is still planar, has the same diameter as the annular gap 6 between the outer pole piece 3 and the inner pole piece 5 on its face 30 facing the support ring 10, and A heat-activated adhesive is applied to the annular area coaxial with 10. This can be done, for example, by immersing the support ring 10 and a ring (not shown) coaxially guided along the inner cylindrical wall 11 in a liquid containing adhesive and then bringing it into contact with the still planar diaphragm material. It is carried out by.

In the third position, the heat-radiating diaphragm forming tool 3 has a recess shaped to correspond to the shape of the final diaphragm 13 as shown in FIG. 4B.
1 is introduced coaxially to the side 32 of the diaphragm material opposite the support ring 10, and at the same time the diaphragm material is subjected to air pressure from the opposite side (support ring 10 side) as shown by the arrow 33 in FIG. 4C. This pressure forces the diaphragm material into a bonding surface against the forming tool surface. The coil 15, which was fitted into the guide mold 21, is pressed onto the heat activated adhesive which is applied to said area of the diaphragm. The coil 15 is precisely guided by the cylindrical wall 22 of the guide mold 21, which is connected to the inner cylindrical wall 11. Therefore, the thermally emissive forming tool 3
The heat from 1 softens the diaphragm material and simultaneously activates the heat activated adhesive to bond coil 15 to diaphragm 13. At the same time, the terminal 8 is pressed into a fixed position in the hole 28 of the support ring 10.

As shown, the support ring 10 has a groove 23 in which the conductor 16 of the coil is placed. The container part 1 has a lateral projection 24 which coincides with the groove 23.
, and this protrusion 24 closes the groove 23 on the outside without clamping the conductor 16 of the coil when the two parts are joined.

Of course, the adhesive may be applied to the coil 15 while it is still on the guide mold 21.
However, it has been found that applying an adhesive to the diaphragm 13 is most convenient.

[Brief explanation of the drawing]

1, 1A, and 1B are a plan view and a sectional view showing the structure of a magnet portion of an electrodynamic transducer constructed according to the present invention, and FIG.
2A and 2B are a plan view and a sectional view showing the structure of the coil diaphragm portion, and FIGS. 3, 3A, and 3B are electrodynamic transformers that combine the two parts. 3C is a plan view and a cross-sectional view of the deuser, FIG. 3C is a cross-sectional view along line C--C of FIG. 3A, and FIGS. 4A and 4B show a forming tool used in the method of the invention; , FIG. 4C shows a view similar to FIG. 2B. DESCRIPTION OF SYMBOLS 1... Container part, 2... Guide pin, 3... Outer magnetic pole piece, 4... Inner magnetic pole piece, 5... Magnet, 6... Magnetic pole gap,
8... Coil terminal, 10... Support ring, 13... Diaphragm, 15... Coil, 21... Guide mold, 31...
Molding tools.

Claims (1)

[Claims] 1. A diaphragm connected to a coil that is axially movable in an annular gap between an inner pole piece and an outer pole piece connected to each pole of the magnet, and separated from the magnet part and It consists of a coil and diaphragm part, and the magnet part has a guide pin, a magnetic pole piece,
A method for manufacturing an electrodynamic transducer which is integrated with a housing part having a guide pin by mounting a unit consisting of a magnet, comprising: an inner cylinder having the same diameter in a first position as the outer cylinder wall of the outer pole piece; Fixing the peripheral edge of one surface of a flat heat-deformable diaphragm material to the side of a support ring with a wall, and in a second position coaxial with the support ring and the center of the annular gap between the two pole pieces. A heat-activated adhesive is deposited on at least one of the annular coil bonding areas of the diaphragm material surface of the same shape as the cross-section perpendicular to the axis and the coil, and in a third position coaxially on the diaphragm material surface opposite the support ring. Guide the diaphragm heating molding tool to the surface of the diaphragm, and at the same time apply pressure of compressed air to the opposite side of the diaphragm material to pressurize the diaphragm material so that it comes into contact with the diaphragm molding tool to form a diaphragm, which is supported on the guide mold. 1. A method of manufacturing an electrodynamic transducer, characterized in that a coil is crimped onto a coil bonding area of a diaphragm. 2. Comprising a diaphragm connected to a coil that is axially movable in an annular gap between an inner pole piece and an outer pole piece connected to each pole of the magnet, and consisting of a magnet part and a separate coil/diaphragm part. The magnet part is attached to the guide pin with a magnetic pole piece,
A method for manufacturing an electrodynamic transducer which is integrated with a container part having a guide pin by mounting a unit consisting of a magnet, comprising: an inner cylinder having the same diameter in a first position as the outer cylinder wall of the outer pole piece; Fixing the peripheral edge of one surface of a flat heat-deformable diaphragm material to the side of a support ring with a wall, and in a second position coaxial with the support ring and the center of the annular gap between the two pole pieces. A heat-activated adhesive is deposited on at least one of the coils and an annular coil bonding area on the surface of the diaphragm material of the same shape as the cross-section perpendicular to the axis, and in a third position coaxially on the surface of the diaphragm material opposite the support ring. Guide the diaphragm heating molding tool to the surface of the diaphragm, and at the same time apply pressure of compressed air to the opposite side of the diaphragm material to pressurize the diaphragm material so that it comes into contact with the diaphragm molding tool to form a diaphragm, which is supported on the guide mold. crimping the coil which is attached to the coil adhesive area of the diaphragm, forming a plurality of pin-like projections integral with the container portion with a substantially circular cross-section, and forming a plurality of pin-like projections on the support ring with the plurality of pin-like projections integral therewith. forming a corresponding number of square cross-section holes, and introducing the plurality of pin-like protrusions into the corresponding square cross-section holes in the assembly of joining the two parts, the coil diaphragm part and the magnet part, to create acoustic resistance; 1. A method of manufacturing an electrodynamic transducer, comprising: forming an electrodynamic transducer.