EP1620867A1

EP1620867A1 - Transformer

Info

Publication number: EP1620867A1
Application number: EP03816858A
Authority: EP
Inventors: Reinhold Schulz; Hans-Jürgen MANS; Michael Becks; Andreas Kniesel; Peter Grad; Wolfgang LÖDDE; Olaf BLÖMKER
Original assignee: Friwo Mobile Power GmbH
Current assignee: Friwo Mobile Power GmbH
Priority date: 2003-05-06
Filing date: 2003-05-06
Publication date: 2006-02-01
Anticipated expiration: 2023-05-06
Also published as: DE50305218D1; CN100530456C; AU2003232732A1; US20070126545A1; US7764157B2; WO2004100192A1; EP1620867B1; CN1768399A

Abstract

The invention relates to a transformer comprising a coil body (1) on which at least one primary coil (2) and one secondary coil (3) are held. The aim of the invention is to provide a transformer that, while using the smallest possible amount of high-grade insulation material, ensures a good insulation and fire-protection function while remaining compact and easy to assemble. To this and, the invention provides a transformer of the above-mentioned type, which is characterized in that the coil body comprises at least one primary part (4), on which the primary coil is held, and comprises a secondary part (5), on which the secondary coil is held. One section of the primary part can be covered by at least one section (6) of the secondary part. This section of the secondary part takes on the function of the fire-protection housing for the primary part of the transformer.

Description

transformer

The present invention relates to a transformer with a coil body on which at least one primary coil and one secondary coil are accommodated.

Transformers of the type mentioned above are used, for example, to supply high-volume consumer products with extra-low voltage. In order to meet the applicable safety standards, such transformers are encased in a housing made of a plastic material which corresponds to a fire protection class UL94-V1 or better. However, such insulation materials are relatively expensive. Many manufacturers therefore strive to use these high-quality materials as little as possible.

An example of this is given in European Patent Application No. 01 309 737.3. In addition to a main housing made of a simple material, a second cover made of a fire protection material is provided for isolating a transformer. The second cover encases a portion of a primary coil of the transformer and connector pins away from the primary winding. This arrangement is relatively complex, in particular with regard to the assembly of the transformer. In addition, the power supply becomes larger and heavier due to the additional second cover.

It is the object of the present invention to provide a transformer which ensures good insulation with the least possible use of high-quality insulation material and yet has a compact structure and can be easily installed.

The object is achieved by a transformer of the type mentioned above, which is characterized in that the coil former has at least one primary part on which the primary coil is accommodated and a secondary part on which the Secondary coil is included; wherein at least a section of the primary part can be covered by at least a section of the secondary part.

This transformer has the advantage that the secondary part has a double function. On the one hand, it carries the secondary coil. Furthermore, at least one section of the secondary part serves to cover at least a section of the primary part, which enables the secondary part to provide insulation and fire protection function for the at least one section of the primary part. By shifting these two functions into the secondary part of the transformer, additional covers can be dispensed with or their number can be reduced, as a result of which the transformer can be manufactured with a compact structure and low weight and its assembly can be facilitated.

According to an advantageous embodiment of the invention, at least a region of the primary coil can be covered by the secondary part. This can be used to isolate the at least one area of the primary coil.

In a preferred example of the invention, at least one contact pin region of the primary part can be covered by the secondary part. This construction has the advantage that at least part of the contact pin area can be isolated.

According to a favorable variant of the invention, the primary part and the secondary part are designed as two parts which can be separated from one another. This enables the secondary part to move relative to the primary part, with which the at least one section of the secondary part can be applied well to the at least one section of the primary part in order to cover it.

The at least one section of the secondary part advantageously has an inner diameter that is larger than an outer diameter of the at least one coverable section of the primary part. This ensures that the at least one section of the secondary part on the at least one coverable section of the primary part can be applied or pushed on, whereby good coverage of this section of the primary part can be achieved.

In a further preferred embodiment of the invention, the secondary part consists of a fire protection material. With this construction, the secondary part can perform a fire protection function.

According to a further advantageous embodiment of the invention, the fire protection material is a plastic material of the flammability class UL94-V1 or better. This material ensures particularly good fire protection that meets the relevant safety standards in a large number of countries.

The primary part is preferably connected to at least one contact pin, which is covered on at least one connection region to the primary part. With this arrangement, the at least one contact pin can be isolated in the connection area to the primary part and additionally fixed in its position.

In a further favorable embodiment of the invention, the primary part is connected to at least one contact pin by means of a one-way plug connection. The one-way plug connection ensures that a contact pin, once connected to the primary part, is held firmly in its position. In this way, the contact pin can be fixed in its position even in the event of a damaged outer housing of the device and protected against contact by a user.

In a further example of the invention, the one-way plug connection has at least one latching element which engages behind the primary part in a connection area. Such a construction ensures simple assembly of the contact pin with the primary part and a high degree of strength of the connection between the contact pin and the primary part.

The at least one contact pin advantageously has an insulated jacket region. This can provide additional protection for a user against contact of live and thus dangerous contact pins, especially if the outer device housing is damaged.

The present invention is described below using advantageous embodiments with reference to the accompanying figures of the drawing, of which

1 shows a perspective view of a primary part and a secondary part of a transformer according to a first embodiment of the present invention;

Figure 2 shows a perspective view of a completed transformer assembly according to the first embodiment of the present invention;

FIG. 3 shows a perspective sectional view of a finished floor assembly with the transformer according to the first embodiment of the present invention;

FIG. 4 shows a perspective view of a primary part and a secondary part of a transformer according to a second embodiment of the present invention;

Figure 5 is a perspective sectional view of a transformer with a

Shows one-way connector according to a third embodiment of the present invention; and

Figure 6 shows a schematic sectional view of the one-way connector of the third embodiment of the present invention.

FIG. 1 shows a perspective view of a primary part 4 and a secondary part 5 of a transformer according to a first embodiment of the present Invention. In the first embodiment of the invention, as shown in FIG. 1, the primary part 4 and the secondary part 5 are designed as separable parts and together form a coil former 1.

The primary part 4 has approximately the shape of an "H" in cross section. The left section of the "H" shown in FIG. 1 forms a connecting section 42 of the primary part 4, which has a connecting area 7 for AC contact pin contacting in its upper region. The middle area of the "H" has an approximately rectangular winding body with rounded corner areas. The winding body serves to receive a primary coil 2 wound thereon. The section of the "H" shown on the right in FIG. 1 forms a winding body limitation 13 for the winding body of the primary part 4 this page. It has a larger diameter d than the winding body with the primary coil 2 wound thereon.

The primary part 4 is hollow inside. In the example shown, an inner opening 45 of the primary part 4 has an approximately rectangular cross section. The inner opening 45 later serves to receive an iron core (not shown in FIG. 1).

The secondary part 5, like the primary part 4, has approximately the shape of an internally hollow "H". The section of the "H" shown on the left in FIG. 1 is designed with an inner diameter D which is larger than the outer diameter d of the winding body delimitation 13 of the primary part 4. It also has a width B which corresponds approximately to a width b of the winding body and the winding body limitation of the primary part 4. The section of the secondary part 5 shown on the left in FIG. 1 later forms a covering area 6 for the primary coil 2 of the primary part 4.

In a region of the secondary part 5 shown at the top left in FIG. 1, the cover region 6 has insulating parts 1.1 for AC contact pins (not shown in FIG. 1). The insulating parts 11 extend approximately at an angle of 90 ° to the direction of diameter D of the secondary part 5. In the embodiment shown, the insulating parts 11 have an approximately rectangular inner cross section and are hollow to cover the AC contact pins or the connection area to the contact pins. In other embodiments of the invention, not shown, the insulating parts 11 can also have a round, elliptical or other polygonal cross section, preferably in adaptation to the contact pins to be insulated.

The secondary part 5 also has a central region of the “H”, which serves as a winding body on which a secondary coil 3 is wound. The winding body of the secondary part 5, similar to the winding body of the primary part 4, has an approximately rectangular cross section with rounded corner regions and has an inner opening 14 for receiving an iron core (not shown in Figure 1).

The section of the "H" of the secondary part 5 shown on the right in FIG. 1 forms a winding body delimitation 15 for the secondary coil 3. The winding body delimitation 15 has a larger diameter than the diameter of the winding body with the secondary coil 3 of the secondary part 5.

Connection areas 16 for a connection to DC contact pins 17 are provided in an area of the winding body delimitation 15 shown at the bottom right in FIG.

Both the base material for the coil former 1, as well as the cover area 6 and the insulating parts 11 of the secondary part 5 are made of a fire protection material of fire protection class UL94-V1 or better. The windings of the primary coil 2 and the secondary coil 3 consist of a metallic material, such as Copper. The contact pins are also made of a metallic material, e.g. Bronze, trained.

FIG. 2 shows a perspective view of a completed transformer assembly 18 according to the first embodiment of the present invention. The transformer assembly shown is formed by assembly from the primary part 4 and secondary part 5 shown separately in FIG. 1. The cover Area 6 of the secondary part 5, the primary coil 2 of the primary part 4. Furthermore, the insulating parts 11 of the secondary part 5 cover the respective connection areas 7 of the primary part 4.

Due to the larger inner diameter D of the cover 6 of the secondary part 5 compared to the outer diameter d of the primary part, the secondary part 5 was pushed onto the primary part 4 during assembly with the primary part 4. As a result, the cover 6 with its width B encompasses the width b of the primary coil 2 and the winding body boundary forms both good electrical insulation for the primary coil 2 and, due to the fire protection material used, good fire protection.

Furthermore, in the embodiment shown, the insulating parts 11 were also pushed onto the connection areas 7 during assembly, so that they encase them except for the contact area. The insulating parts 11 serve both for electrical insulation of the connection areas 7 and, due to the fire protection material used, as fire protection for the connection areas 7.

As shown in Figure 2, the completed transformer assembly 18 has a compact structure. Since dangerous current-carrying areas, such as the primary coil 2 and the connecting areas 7, are covered by the cover 6 and the insulating parts 11, the transformer assembly in the form shown in FIG. 2 can be used without the use of an additional fire protection housing and, despite the simple construction, meets the fire protection requirements in a variety of countries.

In the embodiment shown, the bobbin 1, which consists of two halves, performs a double function. On the one hand, it takes up the wire windings of the primary coil 2 and the secondary coil 3. On the other hand, the coil former 1 fulfills the fire protection housing function required from the standard perspective, whereby the use of additional plastic covers or housing parts can be eliminated or reduced. By minimizing the use of materials, the transformer can be manufactured with a light weight. From Figure 1, the parts formator can be manufactured with a light weight. From FIG. 1, which shows parts of a transformer assembly in the unassembled state, and from FIG. 2, which shows the transformer assembly after assembly, it can be seen that a simple pushing of the secondary part 5 onto the primary part 4 is sufficient to mount the transformer assembly.

FIG. 3 shows a perspective sectional view of a finished floor assembly 12 with a transformer assembly 18 according to the first embodiment of the present invention.

An iron core 20 is inserted into the transformer assembly 18 shown in Figure 2. Furthermore, the transformer assembly 18 is installed in a housing 21 made of a conventional plastic material. Two contact pins 8 protrude from a contact area 22 which projects at an angle from the housing 21. The contact pins 8 are passed through the contact area 22 of the housing 21 and are in electrical connection with the primary part 4 of the transformer assembly 18. The contact pins 8 are AC contact pins that are intended to connect the transformer assembly 18 to an electrical outlet (not shown) in use, to thereby supply the transformer assembly 18 with AC voltage. By using the insulating parts 11 in the connection areas 7 to the contact pins 8 and also by using the cover 6 on the transformer assembly 18, the floor assembly shown in FIG. 3 is protected in terms of fire protection.

The contact pins 8 shown in FIG. 3 are elongated with a round cross section and thus correspond to a contact pin standard typically used in Europe, except in Great Britain. However, the present invention is not limited to such contact pins 8. Instead, other forms of contact pins or more than two contact pins can be used in the present invention.

FIG. 4 shows a perspective view of a primary part 24 and a secondary part 25 according to a second embodiment of the present invention. The primary part 24 is formed separately from the secondary part 25 in the not yet assembled transformer shown. The primary part 24 forms, together with the secondary part 25, a coil former 41.

The primary part 24 of the second embodiment of the invention is, similar to the primary part 4 of the first embodiment of the invention, made up of a connecting section 26, a winding body 27 and a winding body limitation 28. The connecting section 26 has two connecting regions 9, via which a connection to the contact pins 8 is established. The contact pins 8 are covered in the connection areas 9 to the primary part 24, for example by overmolding. A plastic, preferably a plastic of fire protection class UL94-V1, is used as the encapsulation material. As a result of the extrusion coating, the contact pins 8 are fixed in their position relative to the primary part 24 and electrically insulated from the outside. Instead of encapsulation, however, encapsulation or other encasing of the connection areas 9 can also be used. - -

The contact pins 8 in FIG. 4 are plate-shaped, perforated contact pins which are chamfered at the corners in a front area. They therefore correspond to a contact pin standard used in the USA, China and Japan, for example. Instead of these contact pins, however, other forms of contact pins, for example with a round cross section, can be used. Instead of the two contact pins, only one contact pin or more than two contact pins can also be provided.

Following the connecting section 26, the primary part 24 has the winding body 27 with a primary coil 32 wound thereon. A winding body limiter 28 adjoins the winding body 27.

The secondary part 25 has a cover area 29, which is pushed onto the primary coil 32 of the primary part 24 when the coil former 41 is mounted. The cover area 29, similar to the secondary part 5 of the first embodiment of the invention, has insulating parts 44 for covering the connection areas 7 of the primary part 24. These are pushed onto the respective connection areas 7 of the primary part 24 during the assembly of the coil former 41, so that they envelop them. The insulating parts 51, like the cover area 29, are made of a plastic material, preferably a fire protection material of the fire protection class UL94-V1, and thus form not only electrical insulation but also fire protection for the connection areas 9 after the assembly of the coil former 41.

A winding body 30 adjoins the covering area 29, on which a secondary coil 33 is wound. The winding body 30 is then delimited with a winding body limitation 31. Contact areas for DC contact pins 43 are located on the winding body boundary 31.

Figure 5 shows a perspective view of a transformer according to a third embodiment of the present invention. -

Here, a transformer assembly like the transformer assembly 1 of the first embodiment of the invention is built in a case 36. Contact pins 8 protrude from the housing 36 and are in electrical connection within the housing 36 with the primary part 4 of the transformer.

The contact pins 8 have an electrical insulation 37 which envelops at least one edge region of the contact pins 8 within the housing 36. The insulation 37 is made of plastic, preferably a plastic of fire protection class UL94-V1 or better. _ __. - - - - -. - - -

The contact pins 8 are connected in the interior of the housing 36 to the primary part 4 of the coil former 1 by means of a one-way plug connection 10. The one-way connector 10 is plugged in once during the assembly of the transformer and is in the following, also by strong tensile forces such. B. 50 N, not or only very difficult to solve again.

An example of the one-way connector 10 can be found in FIG. 6. The one-way connector 10 is designed such that the contact spring 46 is pushed onto the round contact pin 8. The contact spring 46 is expanded by this joining process. The restoring force of the contact spring 46 and the friction between the contact spring 46 and the contact pin 8 cause the connection to be released only with the application of force.

The one-way plug connection 10 is a safety plug connection, by means of which the contact pins 8 are fixed in their position even in the event of a damaged outer device housing, for example due to impact or incorrect use, and are protected against contact by a user. Even if the outer housing 36 is damaged, the remaining unit, consisting of the contact pins 8 and the coil former 1 of the transformer, can be removed from a mains socket by the user without risk, since the user cannot touch live and thus dangerous parts.

Although the third embodiment of the present invention shown in FIG. 5 has been shown with contact pins 8 according to the European standard, this embodiment can also be used for other standards of contact or connector pins.

Although the transformer of the present invention is formed in two parts in the described embodiments, this is not necessary for the third embodiment of the invention. The transformer can also be formed with a one-piece coil body, which has a primary part, on which the primary coil is accommodated, and a secondary part, on which the secondary coil is accommodated. In this case, the fire protection function is guaranteed by additional plastic parts or straps.

Claims

claims

1. Transformer with a coil former (1, 41), on which at least one primary coil (2, 32) and a secondary coil (3, 33) is received, characterized in that the coil former (1, 41) has at least one primary part (4, 24), on which the primary coil (2) is accommodated, and a secondary part (5, 25) on which the secondary coil (3, 33) is accommodated, wherein at least a section of the primary part (4, 24) of at least one section (6) of the secondary part (5, 25) can be covered.

2. Transformer according to claim 1, characterized in that at least a region of the primary coil (2, 32) of the secondary part (5, 25) can be covered.

3. Transformer according to at least one of claims 1 or 2, characterized in that at least one contact pin area (7) of the primary part (4, 24) of the secondary part (5, 25) can be covered.

4. Transformer according to at least one of the preceding claims, characterized in that the primary part (4, 24) and the secondary part (5, 25) are designed as two separable parts.

5. Transformer according to at least one of the preceding claims, characterized in that the at least one section of the secondary part (5, 25) has an inner diameter (D) which is greater than an outer diameter (d) of the at least one coverable section of the primary part (4, 24) is.

6. Transformer according to at least one of the preceding claims, characterized in that the secondary part (5, 25) consists of a fire protection material.

7. Transformer according to claim 6, characterized in that the fire protection material is a plastic material of the flammability class UL94-V1 or better.

8. Transformer according to at least one of the preceding claims, characterized in that the primary part (4) is connected to at least one contact pin (8) which is covered by the insulating parts (11) to the primary part (4).

9. Transformer according to at least one of the preceding claims, characterized in that the primary part (4) is connected to at least one contact pin (8) by means of a one-way plug connection (10).

10. Transformer according to at least one of the preceding claims, characterized in that the one-way plug connection has at least one latching element (40) which engages behind the primary part (4) in a connection area.

11. Transformer according to at least one of claims 8 to 10, characterized in that the at least one contact pin (8) has an insulated jacket region (37).