Classifications

• • H—ELECTRICITY
  • H04—ELECTRIC COMMUNICATION TECHNIQUE
  • H04R—LOUDSPEAKERS, MICROPHONES, GRAMOPHONE PICK-UPS OR LIKE ACOUSTIC ELECTROMECHANICAL TRANSDUCERS; DEAF-AID SETS; PUBLIC ADDRESS SYSTEMS
  • H04R9/00—Transducers of moving-coil, moving-strip, or moving-wire type
  • H04R9/10—Telephone receivers

Definitions

• Electroacoustic transducer based on the electrodynamic principle.
• the invention relates to an electroacoustic transducer based on the electrodynamic principle, in which a moving coil drives a membrane in an annular gap penetrated by magnetic lines of force, in particular in the form of a receiver capsule for telephone handsets, the transducer of which has an annular permanent magnet.
• Such a converter capsule is described for example in DE-AS 25 03 828.
• the transducer capsule there consists of a can-shaped plastic body open at the front, on the bottom of which the transducer magnet system is seated.
• the membrane extends over the opening of the can-shaped body and is protected against damage by a protective cover.
• Such an arrangement is relatively complicated to manufacture, the membrane usually requires additional dust protection in the protective cover, and because the magnet system is located on the bottom of the can, a special solution must be found for the plug connections which make the ends of the moving coil accessible from the outside.
• the invention has for its object to provide a transducer capsule of the present type, which is cheaper to manufacture, requires fewer components and is therefore simpler in construction and also has acoustic advantages.
• the solution to the problem is characterized in that the magnet system on the open side of the can is arranged transducer housing and the membrane extends between the magnet system and the inner can bottom.
• This construction not only a complete protection of the membrane is ensured, but it results from an rigid connection of the relatively heavy magnet system with the front capsule rim, which is used for storing the capsule in the handset, an extremely stable structure.
• the inventive arrangement of the membrane between the magnet system and the housing base saves on components that are otherwise required for mechanical protection of the membrane. From an acoustic point of view, there is the advantage of a desired poorer radiation of high frequencies, which must be suppressed in telephone systems for reasons of freedom from interference.
• the arrangement of the magnet system according to the invention which takes up a large part of the capsule volume, brings with it an optimal ratio of the volumes in front of and behind the membrane for high sensitivity.
• the magnet system contains an annular permanent magnet, the outer diameter of which corresponds to the inner diameter of the can-shaped converter housing, the inner opening of the permanent magnet representing the sound outlet opening.
• the inner opening of the ring-shaped permanent magnet is only used to connect the parts of the magnet system by means of a plastic pin, and the sound is emitted through an annular gap between the outside of the magnet system and the Housing of the converter is formed.
• FIG. 1 shows a schematic section through a first exemplary embodiment
• FIG. 2 shows the same representation through a second exemplary embodiment.
• the membrane 1 consists of a plastic-coated assembly 4, which contains the ring-shaped permanent magnet 1, the pole ring 2, the magnetic yoke 3, the acoustic friction resistor 6 and two plugs with the solder lugs 8.
• the membrane 5 is also attached with its edge zone.
• the voice coil driving the membrane is designated by 9.
• the can-shaped converter housing consists of the outer wall of the assembly 4 and a cover-shaped bottom 7, which is glued to the assembly 4 to form a unit or is ultrasonically welded.
• the permanent magnet 1 consists of a ferrite material, and it has a relatively large volume in order to generate the required line of force density in the air gap. The permanent magnet 1 therefore has the largest possible diameter, which corresponds approximately to that of the capsule.
• the assembly 4 which is a stable unit in itself, is produced in such a way that the parts of the magnet system and the plugs with the soldering lugs are fixed in an injection mold in an injection mold, and the plastic is then injected thereon. After removal from the mold, only the membrane has to be inserted and the connection between the plunger coil and soldering lugs has to be established, whereupon the cover-shaped bottom 7 is glued or welded. It can be seen from this that such a transducer capsule is largely insensitive to mechanical forces.
• a rare earth permanent magnet is used.
• their volume is much smaller with the same force line density, for example in the case of a ferrite magnet. This is associated with a significant reduction in volume and weight of the transducer.
• the permanent magnet 1 can also be described as ring-shaped, but the small opening in the middle is no longer used to pass sound as in the example described above, but rather to connect the components of the magnet system to one another and to the plastic body. which together with the magnet system forms assembly 4 again. The sound emerges through an annular gap with the friction resistance 6, that is outside the transducer system and not through the same as in the previously described embodiment.
• Both versions have in common that the assembly 4 is provided at its front edge with a flange 10, with which the capsule in the telephone handset can be arranged in the correct position and fixed in this.

Landscapes

• Physics & Mathematics (AREA)
• Engineering & Computer Science (AREA)
• Acoustics & Sound (AREA)
• Signal Processing (AREA)
• Telephone Set Structure (AREA)
• Audible-Bandwidth Dynamoelectric Transducers Other Than Pickups (AREA)
• Spinning Or Twisting Of Yarns (AREA)

Applications Claiming Priority (2)

Publications (1)

Family

ID=3515269

Family Applications (1)

Country Status (5)

Cited By (1)

Families Citing this family (2)

Citations (3)

• 1980
  • 1980-10-02 DE DE19803050350 patent/DE3050350D2/de not_active Expired
  • 1980-10-02 WO PCT/AT1980/000031 patent/WO1981003099A1/de active Application Filing
  • 1980-10-02 CH CH767381A patent/CH653198A5/de not_active IP Right Cessation
  • 1980-10-02 DE DE19803050350 patent/DE3050350C1/de not_active Expired
• 1981
  • 1981-03-18 SE SE8101724A patent/SE8101724L/ not_active Application Discontinuation
  • 1981-03-20 FR FR8105648A patent/FR2478927A1/fr not_active Withdrawn

Patent Citations (3)

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