EP0793243A1 - Transformer - Google Patents

Abstract

The transformer has at least one primary winding and at least one secondary winding. It has a coil body (1) with a first chamber (11) in which the primary winding is arranged and a second chamber (12) in which the secondary winding is arranged. A core, especially a ferrite core (2) can be guided into the coil body (1). The latter has a receiving element (13) for a cover flap (3). The latter only covers part of the primary and secondary windings. The primary and secondary windings adjoin each other in this partial region. The cover flap (3) is formed with a first dividing wall (31) arranged essentially perpendicular to the cover flap (3). The dividing wall (31) is arranged in the assembled state between te first chamber (11) and the second chamber (12).

Description

Technical field

The present invention relates to a transformer according to the preamble of claim 1.

Transformers are used in a wide variety of areas. Among other things, transformers are used for the operation of halogen incandescent lamps, an input voltage of e.g. 230 volts or 240 ... 245 volts is transformed into an output voltage of 6 volts, 12 volts or 24 volts. Output transformers in electronic converters for halogen lamps transform from half the mains voltage (e.g. 115 volts) to e.g. 12 volts.

State of the art

A winding body and a cover cap, each made of plastic, for such a transformer are available, for example, from NORWE, Ing. Norbert Weiner GmbH (see product brochure "Protection class coil former UNI", 11/1991). The known transformer is relatively complex. The cover cap is formed in one piece with walls of relatively small wall thickness. In addition to the relatively complex structure, a further disadvantage of the known transformer is that the assembly of the transformer winding body on the one hand and the part consisting of a cover cap and walls on the other hand is difficult since there are several points of the winding body relative to the corresponding points of the part cover cap and walls must be correctly positioned before plugging together and walls can be easily mechanically bent against each other.

Another disadvantage of the known transformer is that the temperature increase of the windings and the plastic surfaces adjacent to them is relatively large, especially during continuous operation. The known transformer can thus only be operated up to a correspondingly reduced ambient temperature at which permanent insulation is still guaranteed.

Presentation of the invention

Based on this prior art, the object of the invention is to specify a transformer which takes on lower temperature values.

According to the invention, this object is achieved by a transformer, which is defined in the patent claims.

The transformer according to the invention is designed such that on the one hand a large part of the heat developed is dissipated and on the other hand that adequate insulation between the primary and secondary windings is ensured.

This allows the maximum permissible ambient temperature of the transformer to be increased, or if the maximum permissible ambient temperature remains essentially the same, cheaper transformer components (windings, core) with greater heat development can be used.

At the same time, the cover cap or the components which are preferably formed in one piece with it, namely a first partition and a second Partitions, designed so that the assembly of winding body and cover cap is made possible in a simple manner.

The simple and error-free assembly of winding bodies with differently designed chambers for the primary winding or the secondary winding on the one hand and the cover cap on the other hand also serves a first coding element which is arranged on the winding body and a second coding element which corresponds to the first coding element and is attached to the cover cap or is arranged on a component connected to the latter.

The production of the cover cap and the winding body is relatively simple due to their wall thicknesses in spray technology; there are no special requirements for the injection molding tools. No sliders are required for the cap tool. Overall, relatively low tool costs are achieved.

The good insulating properties of the transformer according to the invention also serve an insulating web which is provided on the winding body.

The transformer according to the invention is further designed in such a way that the generation of safety extra-low voltages (Safety Extra Low Voltage SELV) is made possible.

Description of the drawings

Fig. 1-9

einen Wicklungskörper für eine Ausführungsform des erfindungsgemäßen Transformators;

Fig. 10 - 15

eine Abdeckkappe für eine Ausführungsform des erfindungsgemäßen Transformators; und

Fig. 16 - 24

eine Ausführungsform des erfindungsgemäßen Transformators.

The present invention is first described in general terms below, and the invention is subsequently explained in more detail using a preferred exemplary embodiment in conjunction with the figures. Show:

Fig. 1-9

a winding body for an embodiment of the transformer according to the invention;

Figures 10-15

a cover cap for an embodiment of the transformer according to the invention; and

Figures 16-24

an embodiment of the transformer according to the invention.

The invention relates to a transformer which is operated in particular in a frequency range above the mains frequency. The transformer has at least one primary winding and at least one secondary winding and a winding body 1 (FIGS. 1-9, 16-24) on which the primary winding is arranged in a first chamber 11 and on which the secondary winding is arranged in a second chamber 12.

A core 2 (FIGS. 16, 20, 22 and 24) can be inserted into the winding body and, in the preferred operating range (with frequencies above the mains frequency), is in particular a ferrite core.

The winding body has a receiving element 13 (FIGS. 1-3, 6), in particular a groove, which receives a cover cap 3 (FIGS. 10-17, 19, 21 and 24).

The cover cap 3 (FIG. 16) covers only a partial area of the primary winding that is wound in the first chamber 11 and a partial area of the secondary winding that is wound in the second chamber 12. This is the section in which the primary winding and the secondary winding adjoin each other. The cap 3 is thus designed so that a large part of the heat developed in the two windings is dissipated. In the area of the two windings, which is not covered by the cover cap, the heat is emitted directly to the surroundings of the transformer. On the other hand, due to its dimensions, the cover cap ensures adequate insulation between the primary and secondary windings; a ("first") air and creepage distance between the primary and secondary windings runs along the cover cap and is at least 4.5 millimeters, in particular 4.8 Millimeter. The first clearance and creepage distance runs on the one hand from the primary winding via the cover cap 3 to the secondary winding (or also in the opposite direction); on the other hand, the first air and creepage distance runs from the primary winding via a first chamber wall 111, a first partition wall 31 and a second chamber wall 112 to the secondary winding. Furthermore, the first air and creepage distance runs on the one hand from the primary winding below a plate 32 (FIGS. 10-16) to the secondary winding and on the other hand runs horizontally from the primary winding via the receiving element 13.

In view of the first course of the first air and creepage distance, the width of the cover cap surface is at least 4.5 millimeters; a preferred value is 4.8 millimeters. Even at this value, sufficient insulation is formed even when the windings are arranged unfavorably (windings that should be arranged next to each other are actually arranged one above the other).

The cover cap 3 is formed with the first partition wall 31 (FIGS. 16 and 24) arranged essentially perpendicular to the cover cap 3, which is arranged in the assembled state between the first chamber 11 or first chamber wall 111 and the second chamber 12 or second chamber wall 112. The air and creepage distance over the first partition is thus extended in a meandering manner. The wall thickness of the first or second chamber wall is e.g. 0.4 millimeters and the wall thickness of the first partition is 0.6 millimeters.

The cover cap 3 and the first partition 31 are preferably formed in one piece. In particular, the cover cap 3 and the first partition 31 are also formed in one piece with a plate 32 (FIGS. 10-13, 16, 19-24) on which the core rests in the assembled state and with second partition walls 33. The plate 32 is arranged parallel to the cover cap 3. The second partitions 33 connect the cover cap 3 and the plate 32 in the way that plate 32, second partitions 33 and cap 3 form a step-like structure. The stability of complex 3-31-33-32 is achieved in particular by plate 32.

The first chamber 11 has the first chamber wall 111 on its side facing the second chamber 12, while the second chamber 12 has the second chamber wall 112 on its side facing the first chamber 11 (FIG. 1). A double-walled structure is thus provided between the primary and secondary windings, the first partition 31 still being inserted between the two chamber walls.

Both chamber walls 111 and 112 are parallel and spaced from one another in such a way that the first partition 31 is arranged in the assembled state at least in a partial area between the two chamber walls 111, 112.

The first partition 31 is U-shaped (FIG. 12), the U-legs of the partition 31 laterally enclosing the center leg of the core 2 in the assembled state.

The already mentioned second partition walls 33, which are preferably formed in one piece with the cover cap, serve to isolate the first and the second winding from the core 2, respectively.

A second clearance and creepage distance runs between the primary winding and core 2 on the one hand and between the secondary winding and core 2 on the other hand; it is preferably at least 2.0 mm and in particular 3 mm.

The second air and creepage distance is extended by the second partition walls 33, which protrude in particular about 2.5 mm - 2.8 mm above the top of the core 2.

The first and the second chamber of the winding body 1 are in particular of different sizes (chamber 1 is larger than chamber 2). In this case, a first coding element 14 (FIGS. 1, 17; for example a nose) is arranged on the winding body 1, which corresponds to a second coding element 34 (FIG. 11) that is attached to the cover cap 3 or a part connected to the cover cap (for example 33 ) is arranged.

The first and the second chamber of the winding body 1 are in particular not only different in size, but also insulated differently: the insulating material thickness between the primary winding and the core is 0.4 mm (see hatched area in FIG. 5, lateral areas and upper area), while the Insulation thickness between the secondary winding and the core is 0.8 mm (see hatched area in FIG. 8). This configuration has advantages for the placement of the transformer (only less insulation of the components on the board, which are connected to the primary winding, from the core is required).

The winding body 1 of the transformer has an insulating web 15 (FIGS. 1, 4, 7) which is arranged horizontally and thus parallel to the core 2 (FIG. 22)

Spacer feet 35 (FIGS. 10-13, 16, 19-24) are arranged on the plate 32 and serve to fix the transformer on a circuit board.

The invention also relates to the covering cap 3 (FIGS. 10-19, 21-24) or the complex 3-31-33-32 and the corresponding winding body 1 (FIGS. 1-9).

The relatively simple assembly of the complex 3 - 31 - 33 - 32 and the corresponding winding body 1 results from the fact that before the two parts 3 - 31 - 33 - 32 and 1 are pushed together, only the first partitions 31 opposite the receiving element (slot) 13 are to be positioned correctly.

The structure of the winding body 1, the cover 3 and the entire transformer with the ferrite core 2 is shown in detail in the figures.

1 shows the winding body 1, which has a first chamber 11 and a second chamber 12. A first chamber wall 111 of the first chamber 11 and a second chamber wall 112 of the second chamber 12 are immediately adjacent, parallel and spaced in such a way that a first partition (31; Fig. 10) is arranged in the assembled state between the first and second chambers . On the winding body 1, two insulating webs 15 are formed, which are horizontal in the position of the winding body shown in FIG. 1. The insulating webs are arranged in such a way that an at least 3 mm long air and creepage distance between wires guided around wire winding mandrels 16 and a (ferrite) core inserted into the coil or winding body 1 is forcibly realized; they are so arranged that there is sufficient insulation even during production-related fluctuations in the winding wire position.

Furthermore, FIG. 1 shows a nose 14 (“first coding element”) formed on the winding body 1, which corresponds to a second coding element (34; FIG. 15) which is arranged on the cover cap or on a part connected to the cover cap. Furthermore, a receiving element 13, which is designed as a groove, is shown in the figure, which serves to receive the actual cover cap (3; FIG. 10).

FIG. 2 shows a top view of the winding body 1 according to FIG. 1, with the components shown and described there.

3 shows a view of the winding body from below, numbers 1-8 of connections being embossed in the winding body.

4 shows a side view of the winding body, the first coding element 14 in the upper and lower region of the winding body 1 and an insulating web 15 being shown.

FIG. 5 shows the interior of the first chamber 11, and FIG. 6 shows the configuration of the first and second chamber walls 111, 112, which form the receiving element 13 for receiving the actual cover cap.

7 again shows a side view of the winding body with an insulating web 15.

FIG. 8 shows the interior of the second chamber 12 and FIG. 9 also shows the interior of the second chamber 12 with the second chamber wall 112.

Fig. 10 shows the cap 3, which is formed with a partition 31, with side walls, and with a substantially horizontal plate 32. The complex cover cap 3, partitions 31, 33 and plate 32 is thus mechanically sufficiently stable. The plate 32 is preferably 1 millimeter thick. It serves as a support surface for the (ferrite) core 2 and as a support for spacer feet 35.

11 shows this body with second partition walls 33, the plate 32 and the spacer feet 35.

FIG. 12 shows the section C-C according to FIG. 10 and FIG. 13 shows the section D-D according to FIG. 10.

In Fig. 14 this body is again shown, namely from below, which is formed in one piece; it includes the actual cover cap 3, the first partition 31, the plate 32, second partition 33, which can be designed as shown in the figure, the second coding element 34 and spacer feet 35.

Fig. 15 shows the top view of the body shown in Fig. 14.

16 shows the transformer according to the invention, which comprises the winding body 1 described above, a ferrite core 2 and the cover cap 3 with the connected components (31, 32, 33, 34 and 35), the first partition 31 between the chamber walls 111 and 112 lies.

Figure 17 is a top view of the transformer while Figure 18 shows the transformer from below.

FIG. 19 shows the transformer from one side, while FIG. 20 shows a section through the transformer. FIG. 21 again shows a side view of the transformer, while FIG. 22 shows a section through the transformer. 23 also shows the transformer from the side, while FIG. 24 shows a section through the transformer.

The cover cap 3 or the complex 3-31-33-32 on the one hand and the winding body 1 on the other hand each consist of plastic, which is used in a manner known per se for transformers.

Claims (19)

Transformer with at least one primary winding and at least one secondary winding, with a winding body (1) on which the primary winding is arranged in a first chamber (11) and on which the secondary winding is arranged in a second chamber (12) into which a core, in particular a Ferrite core (2) can be inserted, and which has a receiving element (13) for a cover cap (3), characterized in that the cover cap (3) covers only a partial area of the primary winding and the secondary winding, in which partial area the primary winding and the secondary winding meet adjoin, and that the cover cap (3) is formed with a substantially perpendicular to the cover cap (3) arranged first partition (31) which is arranged in the assembled state between the first chamber (11) and the second chamber (12). Transformer according to claim 1, characterized in that the cover cap (3) and the first partition (31) are formed in one piece. Transformer according to one of the preceding claims, characterized in that the first chamber (11) on its side facing the second chamber (12) has a first chamber wall (111), that the second chamber (12) on its first chamber (11) facing side a second chamber wall (112) that the first chamber wall (111) and the second chamber wall (112) are parallel and spaced apart in such a way that the first partition (31) in the assembled state at least in a portion between the Chamber walls (111, 112) is arranged. Transformer according to one of the preceding claims, characterized in that the partition (31) is U-shaped and that the U-legs the partition (31) in the assembled state laterally enclose a part of the core (2) arranged in the winding body (1). Transformer according to one of the preceding claims, characterized in that the cover cap (3) is connected to a plate (32) on which the core (2) is arranged in the assembled state. Transformer according to one of the preceding claims, characterized in that the cover cap (3) is connected to second partition walls (33) which, in the assembled state, are arranged between the first chamber (11) and the second chamber (12) on the one hand and the core (2) on the other . Transformer according to claim 6, characterized in that the covering cap (3), first partition (31), plate (32) and / or second partition (33) are formed in one piece. Transformer according to one of the preceding claims, characterized in that the winding body (1) has a first coding element (14) which corresponds to a second coding element (34) which is arranged on the cover cap (3) or a part connected to the cover cap . Transformer according to one of the preceding claims, characterized in that a first air and creepage distance between the primary winding and the secondary winding in the assembled state is at least 4.5 mm, in particular 4.8 mm. Transformer according to one of the preceding claims, characterized in that the first air and creepage distance runs along the cover cap (3). Transformer according to one of the preceding claims, characterized in that the first air and creepage distance along the first chamber wall (111), the first partition (31) and the second chamber wall (112). Transformer according to one of the preceding claims, characterized in that a second clearance and creepage distance between the primary winding and core (2) on the one hand and between the secondary winding and core (2) on the other hand is at least 2.0 mm, in particular 3 mm. Transformer according to claim 12, characterized in that the second air and creepage distance extends over the second partition walls (33) connected to the cover cap (3) and under the plate (32). Transformer according to one of the preceding claims, characterized in that the winding body (1) has an insulating web (15) parallel to the core (2). Transformer according to one of the preceding claims, characterized in that spacer feet (35) are arranged on the plate (32). Transformer according to one of the preceding claims, characterized in that the wall thickness of the first chamber wall (111) and the wall thickness of the second chamber wall (112) is in each case 0.4 millimeters. Transformer according to one of the preceding claims, characterized in that the wall thickness of the first partition (31) is 0.6 millimeters. Winding body (1) for a transformer according to one of the preceding claims. Cover cap (3) for a transformer according to one of claims 1 to 17.

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