DE2807285B2 - Loudspeakers and process for their manufacture - Google Patents

Description

The invention relates to a loudspeaker according to the preamble of claim 1 and to a Process for its manufacture.

A problem with the production of such loudspeakers, which are used in large series, for example for installation in Motor vehicles are produced, consists in particular in the prefabricated plastic speaker frame for holding the loudspeaker membrane securely on the pole plate of the also prefabricated To attach the magnet system.

In the case of loudspeakers known so far, this is done, for example, with the aid of a screw connection. however, which requires a large number of individual parts. In addition to several screws that is to say, additional washers, serrated or knurled lock washers are required and / or screw locking varnish and the like. Required to achieve the desired security of the connection reach. This complex and time-consuming process is costly mainly because it is very is wage-intensive.

In another known method, the loudspeaker frame is made, for example, in an injection molding process directly connected to the prefabricated magnet system during its manufacture, with am Magnet system provided retaining projections are overmolded with plastic. Also this procedure is very wage-intensive, since the magnet system has to be inserted into the mold when the basket is injected. In addition, this method provides a secure connection, especially with larger magnet systems not guaranteed, because the large cold mass of the magnet system prevents the plastic from the Flows around retaining projections in the desired manner.

A known adhesive connection is also very complex and expensive, since it requires extensive preparatory work of the parts is required, for example, to roughen and attach the adhesive surfaces of the metal part to remove mold release agents adhering to the plastic surfaces. Furthermore, there are special ones for series production Systems, for example for suction and mixing and the like. Required.

It is also known, the pole plate of the magnet system with z. B. to provide one-piece molded solid pin, with which an attached speaker basket to be riveted to the magnet system. Even with this method, however, it is not a safe one Fastening of the loudspeaker frame to the magnet system can be achieved, since the riveting on the peg trained closing heads do not put enough around the plastic, so that the Connection loosens in the event of temperature changes or vibrations.

Long-term tests have shown that this connection can also be achieved without exposure to so-called Cold flow or creeping of the plastic dissolves.

Although this method allows due to the coordinated arrangement of the pins the pole plate of the prefabricated magnet system and the corresponding holes on the prefabricated Loudspeaker basket a simple assembly of the loudspeaker without additional adjustment effort, however it is necessary for a sufficiently secure connection to also use the two loudspeaker parts glue, so that the disadvantages described for glue connections also occur here.

All previously known solutions are therefore not satisfactory because the desired security of the Connection thereby requires a high technical and financial effort.

The invention is now based on the object of an improved loudspeaker with a simple and secure attachment of the loudspeaker frame to the magnet system as well as a simple manufacturing technique and inexpensive method of making the desired connection in building a loudspeaker to accomplish.

To solve this problem, an inventive

ßer loudspeaker designed in such a way that the protruding from the pole fold surface, through holes in the Mounting surface of the loudspeaker frame passing through Pins are designed as hollow pins, the edge of which is bent outwards at the free end forms a closing head that crosses the through-hole.

The pole plate preferably consists of a prefabricated stamped molded part and advantageously has a number of, for example, four with the same radial spacing from one that delimits the air gap Center hole in the pole plate evenly in the circumferential direction distributed hollow pegs.

A particularly advantageous for the preparation of a loudspeaker according to the invention method for encryption · '■ binding of a heavy plate-shaped metal part with a plastic part according to the invention characterized in that the plate-shaped metal part is provided with at least one hollow pin which at the joining with the plastic materials using a. <> through-opening provided therein passes so far that the free end of the hollow pin protruding beyond the plastic part is deformed to form a closing head that extends over the circumference of the through-hole. . '>

The hollow pin is preferably molded in one piece onto the metal part by stamping.

The method according to the invention for the secure connection of heavy metal parts with plastic parts is characterized by the fact that the ic Prefabricated plastic parts or loudspeaker baskets do not require any pre-processing for the connection. The series production of the metal parts or pole plates described is advantageously simple and requires Apart from the usual surface treatment for corrosion protection, no further pretreatment.

The attachment of a loudspeaker frame to the pole plate of the magnet system, which is prefabricated in the usual way then takes place quickly and easily by means of an automatically working machine in which the to Closing head of the hollow pin by roll riveting, vortex riveting or the like. Is formed.

In this way, a safe against shocks connection is achieved, without a previously required additional bonding of connecting to 4 ^r> parts.

The method according to the invention is therefore more economical and enables a particularly cost-effective one Construction of loudspeakers, as the disadvantages of previous methods are avoided. w

Further advantages and features of the invention emerge from the following description and the drawing of a preferred embodiment of the invention. It shows

1 shows a schematically simplified cross section of a loudspeaker according to the invention,

F i g. 2 to illustrate the invention Method in an enlarged scale a connecting device according to the invention for secure Attachment of the loudspeaker basket to the magnet system in front of the closing head picture jng, and

F i g. 3 the in F i g. 2 shown connecting device after the closing head formation.

A section of a dynamic loudspeaker 10, shown schematically in simplified form in FIG. 1, has a Magnet system 12, which for example consists of a permanent magnet 14, a yoke 16, a pole plate 18 and a dust protection ring 20 consists. In one through a central hole in the pole plate and the pole core of the permanent magnet 14 limited annular air gap of the magnet system is one when flowing through of the audio-frequency current moving voice coil 22 provided with a membrane 24 and a Calotte 26 is connected.

A loudspeaker cage 28 prefabricated from plastic is explained in more detail later with the help of Connecting devices 30 attached to the pole plate 18 of the magnet system.

The for example conical membrane 24 is over circumferential beads 32 together with a Sealing ring 34 fastened in the loudspeaker frame 28 and attached by a, for example, in the loudspeaker frame Centering 36 guided axially.

The enlarged illustration of a connection point 30 in FIG. 2 and 3 shows that the invention Connection points for fastening the loudspeaker frame 28 to the pole plate 18 of the one Prefabricated structural unit consisting essentially of a magnet system 12 in one piece on the pole plate 18 molded hollow pin 38 exist, which when placing the speaker frame 28 each by a associated passage opening 40 in an annular holding part of the loudspeaker frame 28 passes through, before the free end of the hollow pin 38 protruding over the holding part, for example by rolling or Vertebral riveting or the like. Is deformed to form a closing head 42, see FIG. 3.

The through-opening 40 is preferably step-shaped on the side facing away from the pole plate: 18 expanded and possibly countersunk so that a perfect and quick formation of a closing head is possible, which then does not protrude beyond the surface of the holding part and by widening the bore 40 a receives additional guidance, which contributes to the security of the attachment.

As already explained, there are several, e.g. B. four hollow pins 38 with the same radial distance from the the central bore of the pole plate 18 delimiting the air gap of the magnet system uniformly in the circumferential direction arranged distributed. These retaining pins then occur when the loudspeaker frame 28 is placed on the Pole plate 18 without additional adjustment effort in the correspondingly arranged holes 40 in the annular Holding part of the loudspeaker frame 28. Subsequently, then in a common Operation of a machine equipped with a corresponding molding tool automatically the Closing heads 42 are formed at the free end of the hollow pin 38.

1 sheet of drawings

Claims (7)

Palent claims: 1. Loudspeaker with a magnet system, one movable in its air gap, with a membrane connected voice coil and a speaker basket also connected to the membrane Plastic, which by means of one-piece on a pole plate of the magnet system that delimits the air gap molded pin is connected to the magnet system, characterized in that the surface of the pole plate (18) protruding through bores (40) in a mounting part of the loudspeaker core (28) Pins are designed as hollow pins (38), the free edge of which is bent outwards and forms a closing head (42) which extends over the through openings of the basket. 2. Loudspeaker according to claim!, Characterized by a pole plate consisting of a stamped molded part. 3. Loudspeaker according to claim 1 or 2, characterized by a number with the same radial distance from one delimiting the air gap Central bore of the pole plate (18) distributed in the circumferential direction of arranged hollow pins (38). 4. Loudspeaker according to one of claims 1-3, characterized in that the in an annular Bracket part of the speaker basket (28) provided through openings (40) on the the side facing away from the magnet system (12) are countersunk. 5. Loudspeaker according to claim 4, characterized in that the countersink is in a step-like manner Expansion of the through opening (40) in the ring-shaped retaining part of the loudspeaker frame is provided. 6. Method for connecting a relatively heavy, preferably plate-shaped metal part with a plastic part, in particular for attaching a loudspeaker frame to the Pole plate of a magnet system in a loudspeaker according to one of the preceding claims, characterized in that the metal part is provided with at least one hollow pin, which passes when the plastic part is placed through a correspondingly arranged through opening therein, and that then over the Plastic part protruding free end of the hollow pin to form a crossover opening Closing head is deformed. 7. The method according to claim 6, characterized in that the hollow pin by stamping is integrally formed on the prefabricated metal part.