JPH0815126B2 - How to connect enamel winding - Google Patents

Description

Description: FIELD OF THE INVENTION The present invention relates to a method for connecting an insulated winding to a contact element by ultrasonic welding, which connection is particularly suitable for use in electronic components. Regarding the method.

[Prior Art] In electrical components such as relays, contactors and other devices, the induction coils used are becoming smaller and smaller as miniaturization progresses. As a result, the coil wire used in this case has an ever-decreasing diameter, which makes the connection of the coil wire more difficult. For example, coil wire with enamel insulation is 30 μm to 100 μm (0.03 mm to
0.1 mm) in the range. Japanese Patent Application No. 60-199299 proposes such a miniature high-frequency coil having a chip structure. In this high-frequency coil, an enameled wire wound in a single layer or multiple layers must be connected to a platelet-shaped contact element. I have to.

Traditionally, enamel-insulated coil wires have been connected by manual, mechanical or fully automatic brazing.
At this time, a temperature of about 500 ° C. is required for brazing the high temperature resistant enameled wire. As a result, heat radiation can damage the material in the immediate vicinity of the brazing area.

Therefore, it is advantageous to employ ultrasonic welding for connection, in which case the enamel insulating layer is also broken by the mechanical action of ultrasonic waves and a welding effect is obtained. However, a problem occurs especially in the case of an enameled wire having a diameter of 0.4 mm or less. This is because when the wire is welded to the connection point, it is weakened by the deformation. Since the set mechanical requirements are generally unachievable, it has traditionally been necessary to weld auxiliary cover platelets together in order to improve the mechanical strength. This cover plate is described in DE-OS 3307773, in particular for laser welding. In the production of high-frequency choke coils with lead wires or recently with terminal lugs, which are produced as so-called chip-type high-frequency chokes, the use of this cover plate increases the cost. This is because the cover plates must be supplied before welding.

[Problems to be Solved by the Invention]

It is an object of the present invention to provide an improved method for connecting thin enamel windings using ultrasonic welding to the contact elements of electronic components.

[Means for solving the problem]

In order to achieve the above-mentioned object, according to the present invention, a ceramic core, a plastic core, or a ferrite core is provided with 100 μm.
A method of connecting the enamel winding to a vertically oriented portion of a small plate-shaped terminal lug of a high frequency choke chip formed by winding an emerald winding having a diameter smaller than m, wherein (a) a winding whose insulation is not removed The end is placed on the terminal lug, (b) each winding end is ultrasonically welded onto the vertically oriented part of the terminal lug by breaking its insulating layer and deforming its cross section, and (c) formed by welding. The bonded area is thixotropic and is wrapped with an organic or inorganic drop-shaped quick-setting adhesive.

The method according to the invention can easily be integrated in a processing line, the welding and the subsequent bonding being carried out in an automated manner.

According to the invention, the advantages of ultrasonic welding of enameled wires, such as a secure connection and a slight temperature load, are taken advantage of, and likewise the conventional disadvantage of low strength is compensated for by covering with an adhesive. Such an adhesive is easy to handle and can be applied as drops onto the weld site. After curing, the adhesive becomes mechanically strong and withstands temperature fluctuations in particular. The volume of one drop of adhesive can be selected to cover the entire deformation. Thereby it is achieved that the strength of the connection is greater than the strength of the enameled wire.

Applying this method to electronic components not only achieves the required simplification of processing and at the same time the required improvement in mechanical stability, but also that the welds of the components are not subject to the effects of climate and corrosion Being protected against it is also achieved. It is also possible to apply a mechanically strong coating to the weld or the entire part.

[Embodiment] The present invention will now be described in detail with reference to the drawings illustrating one embodiment of the method according to the present invention.

In FIGS. 1a and 1b showing the principle of the present invention, 1
Is a metal pedestal, for example a contact element, on which the enameled wire 2 is to be connected. For this purpose ultrasonic welding can be used to advantage, for which the ultrasonic sonic pole is 10,
The accompanying ultrasonic anvil is shown at 11. During ultrasonic welding, the insulating layer is broken by a mechanical action, and the metal parts are connected while being simultaneously deformed by friction welding.

Ultrasonic welding is a problem especially for thin wires with a diameter of 0.4 mm or less. This is because, in that case, the deformation may cause shearing of the wire. When applying a drop of a suitable adhesive 4 after welding on the connection as shown in FIG. 1b, all areas at risk of shearing can be protected and a secure mechanical connection can be achieved.

Especially for ultrasonic welding of wires with a diameter of 100 μm or less,
It is essential that the wire 2 is deformed by pressing the sound pole 10 in advance and subsequently the ultrasonic wave is applied. At this time, for example, an ultrasonic frequency of 40 kHz and a pressing force between 2N and 10N are used, and the work rate is usually in the range of a few watts.

As the adhesive, for example, a one-component adhesive is used. In this case, it is important that the adhesive substance is thixotropic, that is, it does not lose its shape and cures quickly, in order to be used according to regulations. Then, in the automated processing, a drop of adhesive is applied to the welding spot immediately after welding, and the adhesive cures after a few seconds when passing under UV light, so the deformation of the enamel wire 2 as shown in Fig. 1b. A shape that encloses the part is obtained.

A high frequency choke according to an embodiment of the present invention is shown at 20 in FIG. Such a choke consists of a core 21, which may be made of ceramic, plastic or ferrite, on which a single or multi-layer winding 24 of enamel-insulated round wire is provided. Within the framework of such miniaturization of electronic components (0.068 at a measurement frequency of 2 MHz)
For rated inductances of .mu.H to 8.2 .mu.H, for example, dimensions of 3.2 mm.times.2.5 mm.times.1.5 mm and wire diameter of 40 .mu.m), there is an increasing tendency to use large area contact elements instead of the conventionally used leads. For this purpose, the core 21 has an end 22 with a cavity 23 in which a platelet-shaped terminal lug 25 is inserted at the front and rear ends. Since the free end portion of the terminal lug 25 is bent, it can be attached to a printed wiring board or the like.

The coil winding 24 must be connected to the terminal lug 25. For this purpose, the coil winding 24 is placed diagonally over the terminal lug 25 and the end 26 of the coil winding 24 is ultrasonically welded in the manner described above. Terminal rug 25
Then, a drop of the adhesive is applied on the surface. A substantially wart-shaped portion 27 is formed which covers the entire deformed portion of the ultrasonic welding.
A mechanically strong bond is obtained after curing of the adhesive.

It has been shown that in the part shown in FIG. 2, the strength and fatigue strength above the fatigue limit can be obtained by a combination of welding and gluing with contact elements of fine enameled wire. Sufficiently good values were obtained in contact resistance measurement, temperature cycle test and other electrical tests.

In the embodiment described above, it is further advantageous that the weld is protected against climate and corrosion effects.

[Brief description of drawings]

1a and 1b are explanatory views showing the principle of the connection method according to the present invention, and FIG. 2 is a perspective view of an embodiment of the present invention. 1 ... contact element, 2 ... enameled wire, 4, 27 ... adhesive, 20 ... high frequency choke coil, 21 ... core, 24 ... coil winding, 25 ... terminal lug, 26 ... winding Line end.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Josef, Sintler Federal Republic of Germany Regensburg, Alfonse by error Schütlerse 9 (72) Inventor Wilfried, Schierer Federal Republic of Germany Rieden, Zoerowerbeek 4 (72) Invention Kurt, Mart, Germany, Regensburg, Czech Republic 100 (56) References JP 57-1213 (JP, A) JP 52-87687 (JP, A) JP 59- 198711 (JP, A) JP 54-75061 (JP, A)

Claims (1)

[Claims] 1. A method of connecting an enameled wire to a vertically oriented portion of a small plate-shaped terminal lug of a high frequency choke chip constructed by winding an enamel winding having a diameter smaller than 100 μm around a ceramic core, a plastic core or a ferrite core. In (a), the winding ends whose insulation has not been peeled off are placed on the terminal lugs, and (b) by ultrasonic welding, each winding end is oriented perpendicular to the terminal lugs by breaking its insulating layer and deforming its cross section. A method for connecting an enamel winding, which comprises welding onto a portion and (c) wrapping a joint region formed by welding with a thixotropic organic or inorganic drop-shaped quick-setting adhesive.