EP0126451B1 - Two-part, three-legged core - Google Patents

Description

The invention relates to a sheet metal core which is layered on the one hand in the same direction and on the other hand alternately layered from sheet metal cuts, the sheet metal cuts being formed in two parts in the case of sheet metal core layered in the same direction and having three legs and two yokes. in which each one sheet metal part has two outer legs and the other sheet metal part has a yoke, and the two outer legs of one sheet metal part and the yoke of the other sheet metal part are firmly connected to one another by pressing the two sheet metal core parts against one another in the sheet metal cutting plane. The free end of the middle leg formed by the one sheet metal part and the yoke formed by the other sheet metal part interact by means of a short shoulder and a taper, and the middle leg is held at right angles to the leg plane after the two sheet metal core parts are pressed against one another against movements of the free middle leg end is.

In a known (DE-A-16 13628) sheet metal core of this type, the extension at the free end of the middle leg is initially as wide as the middle leg, tapers towards the free end and projects into a recess in one yoke. The dimensions of the shoulder and the recess fit together exactly before pressing against each other. The free end of the middle leg can move in the direction transverse to the plane of the sheet metal relative to the subsequent yoke, even if a plurality of sheet metal cuts are folded together to form a core stacked in the same direction. These mobilities ke ⁱ t becomes larger with greater temperature because the gap between the center leg and subsequent yoke increases with increasing temperature. The mobility is associated with a considerable humming noise, which has so far been sought to be avoided by introducing adhesive between the middle leg end and the yoke. Bonding is labor intensive and often loses its effectiveness at higher temperatures.

The object of the invention is therefore to provide a sheet metal core of the type mentioned, in which the mobility of the free middle leg end relative to the associated yoke is prevented by pressing the sheet metal core parts against one another due to a design of the sheet metal parts given by the punching.

The invention provides, solving this problem, a sheet metal core, which is characterized. that the approach is a small, narrow nose and the secure holding of the middle leg is achieved in such a way that in the case of the sheet metal cuts, the nose area and the sheet metal cutting area lying against it do not have matching dimensions before being pressed against one another and have deformations after pressing against one another.

The nose area and the sheet metal cutting area, which abut each other, are pressed strongly against one another when the sheet metal parts are pressed against one another and are slightly deformed, as a result of which the nose is clamped and thus the immobility of the free middle leg end is ensured. A core according to the invention is distinguished, particularly at higher temperatures, by greatly reduced hum.

It is conceivable to provide the nose on the middle leg end and an associated recess on the yoke. However, it is particularly expedient and advantageous if in the case of the sheet metal cuts the nose is provided on the yoke and the associated sheet metal cut area is provided on the middle leg end. This results in embodiments with special advantages.

A particularly expedient and advantageous embodiment is present when, in the case of the sheet metal cuts, the yoke has two lugs at a distance from one another, which are in contact with the two corner regions of the free middle leg end. In this case, no recesses are provided for the noses, but rather the noses clamp the middle leg end between them over its width.

It is particularly expedient and advantageous if, in the case of sheet metal cuts, the two lugs are provided with the taper on the sides facing one another. The corners of the middle leg end can now be pointed or have the projecting tip caused by the cutting. The tip is molded away between the noses when pressed in.

It is also particularly expedient and advantageous if the sheet metal cuts are used to produce a mutually layered sheet metal, in that the lugs of the yokes are arranged outwardly with respect to the sheet metal core. Usable mutually layered cores can thus also be produced from sheet metal cuts for the sheet metal core according to the invention without disadvantage. The outward-facing nose is advantageous when the sheet metal parts are pressed together because the yoke part provided with the nose is often narrower than the yoke part provided with the outer legs, so that no pressure can be exerted on the narrower yoke part when pressed together. If two lugs are spaced apart, the smaller yoke width is particularly well compensated for when the core is pressed together.

If the nose protrudes into a recess in the context of the invention, the nose and the recess can have many different designs. However, it is particularly expedient and advantageous if the nose in each case is blunted in the sheet metal cuts and protrudes into an acute recess. Such a nose, the z. B. is rounded, squeezes very well into the pointed recess.

A particularly useful and advantageous There is also an embodiment if the recess is provided in the middle in the blunt middle leg end in the case of the sheet metal cuts and the corners of the middle leg end are chamfered with a correspondingly central arrangement of the nose. When punching out such sheet metal parts, the nose and the bevels of the middle leg end are produced simultaneously.

Either the nose and / or the sheet metal cutting area interacting therewith is conical, so that they slide into one another when the sheet metal parts are pushed together. The noses are usually conical. If one of the interacting parts has a corner. which is deformed when pressed together, that is cheap.

When the invention is used on a transformer, i. H. in the case of a core in which the parting line between the middle leg end and the associated yoke is small, the height of the nose is, for example, in the case of small cores. B. 0.5 / 10 to 2/10 mm, in particular 1/10 to 1.5 / 10 mm in size. The width of the nose is z. B. 1 mm and is many times smaller than the width of the middle leg.

It is also possible to apply the invention to chokes. It is namely particularly expedient and advantageous if a clear air gap is provided between the free middle leg end and the associated yoke and the clamping nose is seated on a web bridging the air gap. The web is not much wider than the base of the nose and the disturbance of the magnetic conditions by the web is negligible. However, the hum is also reduced in the case of a throttle due to the invention.

As a rule, apart from the nose, the free end of the middle leg will butt against the associated yoke, although it is also possible for the end of the leg to lie in the yoke. It is important that, without the nose and its clamped fit, there is mobility of the free leg end at right angles to the plane of the sheet and also in the package. It is conceivable that one sheet metal part is a U-shape with the two outer legs and the other sheet metal part is a T-shape; as a rule, however, the invention will be provided on an EI cut. The yoke of one sheet metal part can be arranged between the outer legs of the other sheet metal part or rest on the free ends of the outer legs. The fixed connection of the free ends of the outer legs with the yoke of the other sheet metal part takes place, for. B. by locking, clamping hoods or gluing in a weld, the invention is applied with particular advantage.

• Figur 1 eine Draufsicht auf einen Blechschnitt aus zwei Teilen und mit drei Schenkeln,
• Figur 2 eine Draufsicht auf einen Ausschnitt eines zweiten Blechschnittes aus zwei Teilen und mit drei Schenkeln, kurz vor dem Aneinanderanlegen der beiden Teile,
• Figur 3 eine Draufsicht auf einen Ausschnitt eines dritten Blechschnittes aus zwei Teilen und mit drei Schenkeln,
• Figur 4 eine Draufsicht auf einen Ausschnitt eines vierten Blechschnittes aus zwei Teilen und mit drei Schenkeln,
• Figur 5 eine Draufsicht auf einen Ausschnitt eines fünften Blechschnittes aus zwei Teilen und mit drei Schenkeln,
• Figur 6 eine Draufsicht auf einen Abschnitt eines Blechbandes zum Ausschneiden der Teile eines Blechschnittes aus zwei Teilen und mit drei Schenkeln,
• Figur 7 eine Draufsicht auf einen sechsten Blechschnitt aus zwei Teilen und mit drei Schenkeln,
• Figur 8 eine Stirnseiten-Ansicht eines Kernes aus den Teilen des Blechschnittes gemäß Fig. 1 in einem gegenüber Fig. 1 vergrößerten Maßstab und
• Figur 9 eine Draufsicht auf einen Ausschnitt eines siebten Blechschnittes aus zwei Teilen und mit drei Schenkeln.

Preferred embodiments of the invention are shown and shown in the drawing

• FIG. 1 shows a plan view of a sheet metal cut from two parts and with three legs,
• FIG. 2 shows a plan view of a section of a second sheet metal cut from two parts and with three legs, shortly before the two parts are placed against one another,
• FIG. 3 shows a plan view of a section of a third sheet metal cut from two parts and with three legs,
• FIG. 4 shows a plan view of a section of a fourth sheet metal cut from two parts and with three legs,
• FIG. 5 shows a plan view of a section of a fifth sheet metal cut from two parts and with three legs,
• FIG. 6 shows a plan view of a section of a sheet metal strip for cutting out the parts of a sheet metal cut from two parts and with three legs,
• FIG. 7 shows a plan view of a sixth sheet metal cut from two parts and with three legs,
• 8 shows an end view of a core from the parts of the sheet metal section according to FIG. 1 on a larger scale and FIG. 1
• Figure 9 is a plan view of a section of a seventh sheet cut from two parts and with three legs.

1, a sheet metal cut is designed as an EI cut, the legs of which are of equal length and in which a 1 part extends over the free ends of the three legs. The sheet metal cut consists of an E-shaped part 1, which forms a yoke 2, two outer legs 3 and a middle leg 4, and an I-shaped part 5, which forms the second yoke. Sheet metal parts are layered into corresponding packages and an I package is pressed against an E package. At the joints between the I-packet and the E-packet, a weld 6 is drawn on the outer sides of the outer legs in order to hold the parts together. The sheet metal cut frames two rectangular windows 7.

The middle leg 4 abuts with a blunt free end against the yoke formed by the part 5 along a substantially rectilinear parting line 8. The two corners 9 of the free end are chamfered and rest against a nose 10, which is on the inner edge of the I- Part 5 is provided. The free end is clamped over its width between the two lugs 10. In this way caused by friction, the middle leg 4 of the E-packet is prevented from moving at right angles to the sheet metal plane relative to the I-packet.

According to FIG. 2, a middle leg 4 with a rounded corner 9 at the free end is to be pressed against a nose which has a pointed corner 11. By pressing the sheet metal parts together, the tip of the corner 11 is molded away, i. H. the nose 10 adapts to the curve of the corner 9.

3 illustrates the manner in which a corner 9 of a middle leg is initially provided with a projecting tip 12 due to the cut. This tip 12 is pressed away when pressed together with a conical nose.

4 is a yoke part 5 with a nose 10 provided, which is chamfered on the side facing a middle leg 4. The middle leg 4 is made with a pronounced pointed corner 11, which is molded away when the core parts are pressed together.

Fig. Shows an embodiment in which only one nose is provided, which protrudes into a recess 13. Nose 10 and recess are arranged on the center line of the middle leg 4. The recess 13 is pointed and the nose 10 is blunted. Before the parts are pressed together, the nose is somewhat wider than the recess and, after being pressed together, sits in the recess with clamping and with increased friction. The corners of the free end of the middle leg 4 are chamfered, in the way that occurs when punching the central nose 10, which sits here on the yoke 5.

FIG. 6 explains the stamping of I-parts 5 and I-parts 1 from a sheet metal strip 14, one nose and one recess being provided for each sheet cut. The free end of the middle leg of the E-part lies on the connecting line between two lugs 10, on the center of which a diamond-shaped opening 15 is punched, which results in the recesses in the middle legs.

FIG. 1 shows an end face of a core, in which a core yoke is alternately formed by an I part 5 and an E part 1. The 1 part is provided on the outside with two spaced-apart lugs 10 which project outwards beyond the outer edge of the E parts.

In the embodiment according to FIG. 7, an I-part 5 is shortened and an E-part 1 has two elongated outer legs 3, which accommodate the I-part between them. The two sheet metal parts 1, 5 are fastened to one another by two weld seams 6, which run between the ends of the I part and the free ends of the outer legs of the other sheet metal part 1. A clear air gap 16 is provided between the free end of the middle leg 4 and the associated yoke, as is the case with a throttle core. On the yoke 5, two webs 17 are provided, which extend from the inner edge of the yoke 5 and extend to the free end of the middle leg 4. Each web 17 ends in a nose 10 and the two lugs 10 take the free end of the middle leg between them. as is also the case with the sheet metal cut according to FIG. 1.

In the embodiment according to FIG. 1, an opening 18 is provided in the yoke 5 near the inner edge and the sheet metal area, which is located between the opening and the inner edge, is bent outwards as a nose 10. When the core parts layered from the two sheet metal parts are pressed together, the bent sheet metal region 10 is pushed back until the inner edge of the yoke and the edge of the free end abut one another. Here too, the nose 10 is provided on the middle leg, which is preferred. It is also possible. provide the opening 18 in the middle leg near its free end, opposite the nose 10.

In itself, a press fit is sufficient, in which the nose rests with increased friction. As a rule, however, the nose area and the sheet metal cutting area, which abut one another, have dimensions which do not match before being pressed against one another. It is sufficient for this if either the inner edge of the yoke or the abutting edge of the middle leg is notched one or more times by impact and the resulting jagged, fine noses claw into the pressed-against edge and are pressed back a little by it.

Claims (9)

1. A laminated core made up of electrical sheet-steel laminations in the same direction, each lamination being in two parts and having three limbs (3, 4) and two yokes (2, 5), one part (1) of each yoke having two outer limbs (3) and the other part having a yoke (5) and the two outer limbs of one part and the yoke (5) of the other part being firmly joined together by pressing the two parts in the lamination plane, the free end of each central limb (4) formed by one part and the yoke formed by the other part (5) co-operating via a short projection and a tapering part, and after the two parts have been pressed together the central limb (4) is held at right angles to the limb plane and secured against motion by the free end of the central limb, characterised in that the projection is a small, narrow lug (10) and the central limb (4) is held and secured as follows : the lug region (10) and adjacent region (9,13) of each lamination have non-matching dimensions before being pressed together and are deformed after pressing together.

2. A core according to claim 1, characterised in that the lug (10) of each lamination is provided on the yoke (5) and the associated lamination region (9) is provided at the end of the central limb (4).

3. A core according to claim 1 or 2, characterised in that in each lamination the yoke (5) has two spaced-apart lugs (10) abutting the two corner regions (9) of the free end of the central limb (4). (Fig. 1

4. A core according to claim 3. characterised in that in each lamination the two lugs (10) are tapered on their facing sides.

5. A core according to claim 1 or 2, characterised in that in each lamination the lug (10) is truncated and projects into an acute angled recess (13) (Fig. 5).

6. A core according to claim 1. or 5 characterised in that in each lamination the recess (13) is formed in the centre of the truncated end of the central limb (4) and the corners (9) of the end of the central limb are bevelled when the lug is disposed in the corresponding central position.

7. A core according to any of the preceeding claims, characterised in that in each lamination a considerable air gap (16) is provided between the free end of the central limb (4) and the associated yoke (5) and the adjacent lug (10) rests on a web (17) bridging the air gap (Fig. 7).

8. A core according to claim 1 or 2 characterised in that in each lamination an apperture (18) is formed in the yoke of one part of the lamination near the edge adjacent the free end of the central limb (4), and the part of the lamination between the aperture and the free edge of the yoke is bent into a lug (10) before the parts of the lamination are pressed together and is pressed back after the parts have been pressed together (Fig. 9).

9. A core made up of laminations according to any of claims 2-8 but varying in that the laminations are in alternating directions, characterised in that the lugs (10) of the yokes (5) extend outwards relative to the laminated core (Fig. 8).

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