JPH0888130A - Chip inductor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a chip inductor, which has winding end parts welded to contact elements and can be automatically mounted in a cycle time of one second or shorter. SOLUTION: An interior core part 4, which consists of a ferromagnetic or non-conductive material, can be wound single foldedly or manifoldly and has a winding space 5, which is pulled in from the parallel end surface parts 8 of the core part 4. Winding end parts 9 are fixed on contact elements 2, which are provided on the end surface sides of the core part 4 by an indirect welding. The elements 2 have a coating made of soft solder. Moreover, these elements 2 respectively have recessed parts, which are installed as winding start and winding end places and at the same time are used as a shielding material and a welding material at the time of indirect laser welding.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a solid core part made of a ferromagnetic or non-conductive material, in particular ferrite, ceramic or plastic, which can be wound in a single or multiple manner and which is drawn in from parallel end faces of the core part. In particular, it relates to chip inductors, such as air gap coils, reactors or transformers, with open windings.

[0002]

2. Description of the Related Art Such a chip inductor is known from EP-A-0177759. The core part described therein has, in the area of the end face, a recess intended to accommodate a thin plate-shaped contact element,
The winding is welded to the contact element.

The welding of known chip inductors is carried out ultrasonically according to EP-A-02001414, in which a winding insulated by a resist is connected to a contact element. The mechanical strength of the electrical connection is then increased by covering the welded site with a drop of adhesive. The disadvantage of this ultrasonic welding method is that only contact elements with a silver surface coating can be used. However, this creates problems because of the formation of silver sulfide during brazing in the platen, and can also lead to undesired enrichment of silver in the wax bath. On the other hand, if the contact element has a soft brazing coating, ultrasonic welding cannot form a sufficient electrical connection. This is because the lubricating action of tin or tin / lead prevents the formation of weld connections that are durable to use.

Contact elements having a silver surface in the welding area and a soft brazing coating in the brazing area to the platen must be economically unprofitable due to the tight tolerances required for chip inductors. It is impossible to manufacture.

Further, the minimum welding time of about 0.5 seconds required for ultrasonic welding is a cycle time of about 1 second even if the member and the welding electrode are automatically guided.

A reduction in cycle time may be possible with the direct laser welding method known from DE 40 39 527 A1, but this method also does not shield the windings to be connected from laser irradiation. Done without system holder. However, the implementation of the method proposed therein requires extensive research and development on new bonding, welding and winding techniques.

Further, German Patent Application Publication No. 33
From 077773, an indirect laser welding method for contact springs is known, which shields a thin insulated winding against direct laser irradiation by means of a thin plate (sandwich process), in which case the thin plate and the winding are wound. The starting point is a different part on the device. That is, the material at the winding start portion is neither a shielding material nor a welding material. The problem with this method lies in the large mechanical outlay required for positioning the system holder with the contact element and the core, the start and end elements and the two shielding lamellas during laser welding.

Published German patent application No. 2946
No. 626 describes another method of indirectly laser welding. In that case, for example, the conductor wire, which is the winding end of the coil, is brought into contact with the terminal pins of the support plate or of the printed circuit board, the terminal pins being configured as parts of the stamped circuit contained in the support plate or It is welded into the circuit of the printed circuit board. However, this method cannot be used for SMT technology. This is because it is impossible to bring the coil into contact with the terminal on the platen by a known high-power automatic mounting device. In the case of the SMT chip inductor, the coil must be brought into contact with the electrical terminals of the device in order not to deteriorate the assembly performance of the automatic mounting apparatus. Although not included in the German Patent Publication No. 2946626, the terminal pin wound on the device terminal requires a small size for a chip inductor, and therefore, a technical problem required for winding. Due to the additional cost of automatic winding.

From EP-A-0410211, a copper wire having a heat-resistant and high-heat-resistant resist insulator using a hard solder containing phosphorus is indirect laser welded to a terminal of an electric device. Brazing welding methods for connecting elements are known. This method is still not suitable for SMT inductors. This is because the brazing temperatures that can be used in chip inductors do not result in the sufficient wetting required for hard solder. Therefore, an electrical terminal with a hard solder surface in the welding area and a soft solder surface in the brazing area would be required. However, for chip inductors such terminals are almost unusable, as are those having a combination silver and soft solder surface.

[0010]

SUMMARY OF THE INVENTION The object of the invention is to provide a chip of the type mentioned at the beginning, whose winding ends are welded to the contact element and which can be mounted automatically with a cycle time of less than 1 second. It is to provide an inductor.

[0011]

SUMMARY OF THE INVENTION According to the invention, the object of the invention is that the winding ends are fixed to the contact element by indirect laser welding, the contact element having a coating made of soft solder, and It is solved by having a concave portion installed as a winding end portion, and at the same time used as a shielding material and a welding material in indirect laser welding.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described in detail below with reference to embodiments and drawings.

1-3, a solid core portion 4 having a winding gap 5 is shown. In the winding space 5 there is arranged a winding 6 of a chip inductor, which is preferably made of copper wire with a high temperature resistant resist insulation. The contact element 2, which is part of the system holder 1, is fixed to the end face 8 of the core part 4 and is preferably attached. The system holder 1 made of CuSn _6, for example, has a surface coating made of soft solder, preferably tin or a tin-lead alloy.

The contact element 2 has a recess 7, which additionally serves as the winding start and winding end points of the end 9 of the winding 6. Furthermore, the contact element 2 is designed to be used both as a shielding material and as a welding material during indirect laser welding. As can be seen in particular in FIG. 3, the end 9 of the winding 6 is guided in the contact element 2,
In the region of the recess 7, a sandwich is passed between the parts which contact the contact element 2. The welding spot 10 is formed within this range.

Furthermore, the contact element 2 has a slit 3 so that the three-dimensional positioning of the core part 4 can still be obtained in the system holder 1, but the contact element 2 is interrupted by this slit 3.

Completion of the chip inductor with the system holder 1 avoids winding start and end pins on the device. The sandwich method with the contact element 2 used at the same time as a shield and a welding material eliminates the expense of positioning, which requires a separate shield lamella. The contact element 2 having the slit 3 and the recess 7 exhibits higher performance as a chip inductor than a contact element which is not interrupted by the recess serving as a short-circuit winding.

The surface of the contact element 2 made of soft solder is what is demanded by the user as a standard technique today.
Also, welded joints are more robust than brazed joints, and windings with heat or high heat resistant resist insulation allow the device to be used at temperatures above 125 ° C.
It also makes it possible to spray-apply high temperature thermoplastics as described in DE-A-4023141. Also, laser welding requires welding times on the order of milliseconds only, thus enabling cost-required cycle times of less than 1 second.

[Brief description of drawings]

FIG. 1 is a side view of a chip inductor according to the present invention.

FIG. 2 is a plan view of a chip inductor according to the present invention.

FIG. 3 is an enlarged end view of the chip inductor according to the present invention.

[Explanation of symbols]

 1 System Holder 2 Contact Element 3 Slit 4 Core Part 5 Winding 6 Winding 7 Recess 8 End Face 9 Winding End 10 Welding Point

 ─────────────────────────────────────────────────── ─── Continuation of the front page (71) Applicant 390041508 Siemens, Matsushita, Components, Gezelshyaft, Mitt, Besilyenktel, Haftung, und, Companion, Comandate, Geselsyaft Siefelt Science Sights, Things, Things, and Things, Things, Things Federal Republic of Germany Miyunchen (no street number) (72) Inventor Wilfried Schieler, Federal Republic of Germany 89522 Heidenheim Degenhardt Siyutrase 26 (72) Inventor Manfred Espenhain, Federal Republic of Germany 89522 Heidenheim Landshuttraße 6 (72) Inventor Hans-Dieeter Eckart, Germany 89542 Helbrechtingen Wiedenwiesen 26 (72) Inventor Winfried Glauer, Germany 73430 Aalen Franz-Schubert-Schutrasse 6 (72) ) Inventor Uwe Hildebrand Germany 81737 Miyunchen Huazangarten Schutler 1 Ar (72) Inventor Ralph Fumke Germany 13089 Berlin Chinius Schutler 55 (72) Inventor Rothal Hock Germany 12307 Berlin I Ritsuhishi Yutrase 17

Claims (7)

[Claims] 1. A solid core part made of a ferromagnetic or non-conductive material, in particular ferrite, ceramic or plastic, which can be wound in single or multiple folds and which is retracted from the parallel end faces (8) of the core part. In a chip inductor such as a gap coil, a reactor or a transformer having a winding gap, the winding end (9) is fixed to the contact element (2) by indirect laser welding, and the contact element (2) is softened. Has a brazing coating and also has recesses (7) in which the contact elements (2) are provided as winding start and winding end points,
At the same time, the chip inductor is used as a shielding material and a welding material during indirect laser welding. 2. The chip inductor according to claim 1, wherein the coating is made of tin or a tin / lead alloy. 3. The contact element (2) comprises a system holder (1).
3. The structure according to claim 1 or 2, characterized in that
The listed chip inductor. 4. The contact element (2) has a slit (3) so that a three-dimensional positioning of the core part (4) can still be obtained in the system holder (1), the contact element (2) ) Is interrupted by a slit (3). 5. Chip inductor according to claim 1, characterized in that the contact element (2) is fixed to the end face (8) of the core part (4) by means of an adhesive. 6. The contact element (2) with a soft brazing coating consists of CuSn _6.
The chip inductor according to any one of 1. 7. Chip inductor according to claim 1, characterized in that the winding (6) is preferably made of high temperature resistant copper resist wire.