GB2250864A

GB2250864A - Terminals for coils

Info

Publication number: GB2250864A
Application number: GB9125976A
Authority: GB
Inventors: Giovanni Arturo De; Antonio Lucca
Original assignee: Veglia Borletti SRL
Current assignee: Veglia Borletti SRL
Priority date: 1990-12-11
Filing date: 1991-12-06
Publication date: 1992-06-17
Also published as: BR9105484A; FR2674062A3; DE9115311U1; ES2056716B1; IT220750Z2; ES2056716A1; IT9053424V0; FR2674062B3; GB9125976D0; IT9053424U1

Abstract

The coil includes a pair of electrical terminals (27) co-moulded with a flange (18) of the spool (12), the terminals projecting in the same direction and being connected to the ends of the winding. The terminals (27) each include a first zone (42) shaped with two parallel flat surfaces (44) one of which supports a portion of the end of the winding to be soldered. Each terminal (27) also includes a further zone (43) shaped with two more flat surfaces on which several turns of the winding ends are wound. Each terminal (27) additionally includes a third zone provided with a notch (47, 48) within which the ends of the winding are hooked. Finally, the ends of the terminals are cut just beyond the solder joints and the terminals are then bent towards each other. <IMAGE>

Description

AN ELECTRICAL COIL AND METHOD OF MANUFACTURE THEREOF The present invention relates to an electrical coil comprising a spool of insulating material and an electrical winding, as well as to a method of manufacture thereof. In particular the invention relates to a coil in which the spool is provided with a core and at least one flange carrying two terminals of conductive material.

In a known coil of the above-mentioned type, each of the two terminals is formed from an L-shaped metal insert having two circular-section arms. The two inserts are co-moulded with two projections of the flange in such a way that one arm of each insert is parallel to the axis of the spool whilst rie other arm is parallel to the flange. The two arms parallel to the flange are, moreover, parallel to one another but project in opposite directions. These arms constitute the terminals for the connection of the two ends of the winding, for example by soldering.

This coil has various disadvantages. First of all the projection of the terminals in opposite directions and their circular sections make it difficult to fix the ends of the winding temporarily to keep its turns under tension on the core. Moreover the temporary connection of copper or brass conductors of circular section by means of several turns on the terminal, which is also of circular section, is insecure since the soldering must take place along the points of contact of the generatrices of the conductor and the terminal.

The object of the invention is that of providing an electrical coil which is of maximum simplicity and which will overcome the aforesaid disadvantages of known coils.

This object is achieved with the electrical coil of the invention which comprises a spool of insulating material and a winding of an electrical conductor having an input end and an output end, the said spool being provided with a core and at least one flange carrying two terminals of conductive material, one of the said terminals being connected to the said input end, the other terminal being connected to the said output end, the said terminals being disposed parallel to the said flange and being comoulded with two projections extending from the outer surface of the said flange, and is characterised by the fact that the said terminals extend in the same direction and are soldered to the said ends substantially at the same distance from the said projections.

For a better understanding of the invention a preferred embodiment of the coil will be described here, by way of example, with the aid of the attached drawings, in which: Figure 1 is a partially sectioned side view of an electrical coil according to the invention; Figure 2 is a partially sectioned front view of the coil of Figure 1; Figure 3 is a side view of the spool of the coil before the winding is wound onto it; Figure 4 is a view of the spool of Figure 3 from the line IV-IV; Figure 5 is a view of the spool of Figure 3 from the line V-V; Figure 6 is a section on an enlarged scale of a detail of Figure 5 taken on the line VI-VI; Figure 7 is another section on an enlarged scale of the detail of Figure 5, taken on the line VII-VII; Figure 8 is a side view of the spool with its winding in another phase of manufacture; Figure 9 is a view taken on the line IX-IX of Figure 8;; Figure 10 is a section taken on the line X-X of Figure 8; and Figure 11 is a section taken on the line XI-XI of Figure 9.

With reference to Figure 1, the reference numeral 11 generally indicates an electrical coil which comprises a spool 12 of insulating material and a winding 13 comprising a series of turns 14 of an electrical conductor 15, for example a conductor of cylindrical copper wire clad in an insulator. The turns 14 are wound on a tubular core 16 of the spool 12 in which there may possibly be inserted a cylindrical core of magnetic material, not indicated in the drawings.

The core 16 is delimited by two substantially flat flanges 17 and 18 (Figure 3). The flange 17 (Figure 4) has a circular form and is provided with a peripheral projecting edge 19 in which are formed two diametrally opposed reference notches 21. On its outer surface the flange 17 also carries four circular projections 22 disposed at 900 from one another.

The flange 18 (Figures 3 and 5) has an inner surface 25 and an outer surface 29. From its outer surface 29 extend two diametrally opposite projections 23 at 900 with respect to the notches 21. In each projection 23 there is co-moulded a corresponding L-shaped metal insert 24.

Each insert 24 includes an arm 26 of greater diameter disposed parallel to the axis of the core 16 and having the function of a connection pin. Each insert 26 further includes an arm 27 of smaller diameter than that of the arm 26 and disposed parallel to the flange 18.

In particular, the arms 27 are parallel to one another and both extend in the same direction, perpendicular to the diametral direction on which the projections 23 are disposed. In correspondence with the two arms 27, the flange 18 is provided with two cut-out portions 28 each having an L-shaped edge, the longer side of which is parallel to the arm 27 itself. The outer surface 29 of the flange 18 is flat but its circular edge 30 has a conical outer surface.

The arms 27 of the two inserts 24 serve as respective connection terminals for an input end 31 (Figure 2) and an output end 32 of the winding 13 for which reason the arms 27 will hereinafter respectively be called the input terminal (to the right in Figures 2 and 5) and output the terminal (to the left in Figures 2 and 5).

Close to the output terminal 27, the flange 18 is provided with two peripheral slots 33 and 34 separated by a segment 36 of predetermined length. The two slots 33 and 34 are disposed in the quadrant of the flange 18 downstream of the output terminal 27 in the sense of the turns 14 of the winding 13. Each of the two slots 33 and 34 has the shape of an anchoring bollard, with a C-shaped portion on the side towards the output terminal 27.

The slot 33 serves (Figures 8-10) as a hook for the output end 32 of the winding 13, inverting its direction so that a portion 35 of this end 32 passes over the outer surface 29 of the flange 18. The slot 34 serves to return the end 32 of the winding 13 onto the inner surface 25 of the flange 18. The slots 33 and 34 are therefore able to maintain the turns 14 firmly clamped to the core 16 whilst the connection of the end 32 to the associated terminal 27 is effected.

In order to prevent the portion 35 of the end 32 of the conductor 15 projecting above the outer surface 29 of the flange 18 between the two slots 33 and 34, the outer surface of the segment 36 is flat and forms a step 38 the height of which is at least equal to the diameter of the conductor 15 so that the segment 36 is thinner than the flange 18.

The projection 23 is such that each terminal 27 remains substantially outside the outer surface 29 of the flange 18. In the region of the cut-out portion 28 adjacent the input terminal 27, the flange 18 has means for allowing a gradual passage of the input end 31 (Figures 9-11) of the winding 13 from the terminal 27 to the core 16 of the spool 12.

In particular these means comprise a strip 39 forming the larger side of the associated L-shaped cut-out portion 28 and having a smaller thickness than that of the flange 18. The strip 39 is flush with the outer surface 29 of the flange 18 and delimits an elongate aperture 40 passing through the flange 18 substantially tangentially of the core 16 and perpendicular to the strip 39. At the peripheral end of the strip 39 the flange has a further cut-out portion 41 to facilitate the starting of the winding as will be seen better hereinafter.

The form of the spool 12 (Fi.n res 3-5) and in particular of the flanges 17 and 18 and the inserts 24, allows a very simple moulding by means of a mould comprising two axially counterposed dies and two diametrally opposed radial shells. The dies serve to form the outer surfaces of the flanges 17 and 18 and have projections for forming the inner surfaces of the core 16, the slots 33 and 34, and the elongate aperture 40 of the flange 18. The shells of the mould are movable parallel to the terminals 27 and serve to form the outer surface of the core 16, the step 38 for the strip 39 and the two notches 21 (Figure 4) in the flange 17.

Before the conductor 15 is wound onto the spool 12, the two terminals 27 (Figures 5-7) are cold deformed in such a way as to obtain a first, relatively long, central zone 42 and a second, end zone 43. In particular, in the zone 42 each terminal 27 is squeezed transversely with respect to the axis of the spool 12 to obtain two flat parallel surfaces 44. Moreover, in the zone 43 each terminal 27 is squeezed in an axial direction to obtain two flat surfaces 46 perpendicular to the surfaces 44.

The input terminal 27 has a third zone, adjacent the projection 23, provided with a notch 47, for example a Vshaped notch, disposed adjacent the outer surface 44 of the zone 42. In turn, the output terminal 27 has a third zone adjacent the projection 23 provided with a similar notch 48 disposed adjacent the inner surface 44 of the associated zone 42. In this way the two inserts 24 are identical.

The winding of the coil 13 on the spool 12 thus prepared is effected in the following manner.

First, the input end 31 of the conductor 15 is formed into a plurality of turns 49 (Figures 9-11), for example three turns, on the zone 43 of the relative terminal 27, these turns being disposed adjacent one another and towards the end of the terminal 27. By pressing the conductor 15 is such a way as to make it adhere to the flat surface 46 (see also Figures 6 and 7) slipping or rotation of the turns 49 on the zone 43 is prevented.

A portion 51 of the input end 31 is then bent back so as partly to overlap the turns 49 and lock them further.

The portion 51 thus adheres to the flat outer surface 44 of the zone 42. From there a further turn 52 is formed in the end 31 and is lodged in the notch 47 of the terminal 27. Now a portion 53 of the end 31 engages the strip 39 so that the conductor 15 can reach the core 16 substantially without further bending.

The turns 14 (Figure 2) are now formed starting from the first internal turn adjacent the flange 18 so as to create a series of superposed layers of these turns 14 on the core 16. The last outer turn 14 is also disposed adjacent the flange 18.

After this last turn 14 has been formed, the output end 32 (Figures 8-10) of the conductor 15 is engaged in the slot 33 whereby the direction of the conductor 15 is reversed, automatically holding the wound turns 14 under tension. The portion 35 of the end 32 now rests on the segment 36 and is then engaged in the slot 34 with a portion 54 thereof again passing over the inner surface 25 of the flange 18.

From here a portion of the end 32 is bent substantially at 900 over the smaller side of the cut-out portion 28 and contributes to holding the turns 14 locked. Subsequently the end 32 is formed into a turn 56 which is engaged in the notch 48 of the output terminal 27. From here a portion 57 of the end 32 is formed, which adheres to the outer flat surface 44 of the zone 43 (see also Figures 6 and 7).

Finally, the end 32 is wound on to the zone 44 of the output terminal 27 so as to form a plurality of adjacent turns 58 close to the end of the terminal 27 itself. The turns 58 are pressed against the flat surface 46 of the zone 43 thereby preventing sliding or rotation of the end 32 on the terminal 27. The winding is thus completed and the conductor 15 can be cut off.

The ends 31 and 32 are now soldered to their respective terminals with two spots of solder on two flat portions 59 and 60 of the two outer surfaces 44 disposed substantially adjacent the middle of these two surfaces 44 so that the soldering material adheres over a wide contact zone. Finally the two terminals 27 and the associated ends 31 and 32 are cut off immediately beyond the portions 59 and 60 and are bent towards each other to assume the convergent form shown in Figure 2.

The method of producing the coil 11 consists essentially of a phase for prearranging the spool with the inserts 24 as described with reference to Figures 3 to 7, a winding phase as described with reference to Figures 8 to 11, and a phase of soldering, cutting and bending the terminals 27 to obtain the configuration described with reference to Figures 1 and 2.

From the above the advantages of the coil of the invention over known coils will be apparent. In fact the two slots 33 and 34 and the form of the terminals 27 prevent loosening of the turns 14 during winding.

Moreover the form and orientation of the terminals 27 make it possible to form the spots of solder on the flat portions 59 and 60 with a very simple soldering iron having two opposed soldering tips. Finally, both the cutting of the terminals 27 and the associated bending can be effected with very simple and symmetrical tools.

The coil and associated method of manufacture described can have various modifications and improvements introduced thereto without departing from the ambit of the claims. For example, the notches 47 and 48 can be annular rather than in a plane. Moreover there may be a different number of turns of the ends 31 and 32 on the respective zones 43 and these could be in a different direction from that described above. Finally, the deformation of the terminals 27 with the associated notches 47 and 48 can be effected on the inserts 24 before moulding of the spool 12.

Claims

1. An electrical coil comprising a spool (12) of insulating material and a winding (13) of an electrical conductor (15) having an input end (31) and an output end (32), the said spool (12) being provided with a core (16) and at least one flange (18) carrying two terminals (27) of conductive material, one of the said terminals (27) being connected to the said input end (31), the other terminal (27) being connected to the said output end (32), the said terminals (27) being disposed parallel to the said flange (18) and being co-moulded with two projections (23) extending from the outer surface (29) of the said flange (18), characterised by the fact that the said terminals (27) extend in the same direction and are soldered to the said ends (31, 32) substantially at the same distance from the said projections (23).

2. A coil according to claim 1, characterised by the fact that the said terminals (27) each include a flat portion (59, 60) for engagement with the said end (31, 32) to be soldered.

3. A coil according to Claim 2, characterised by the fact that each of the said portions (59, 60) is formed on a first zone (42) of the said terminals (27) adjacent the corresponding projection (23) and is shaped in such a way as to present a pair of flat parallel surfaces (44).

4. A coil according to Claim 3, characterised by the fact that each said flat portion (59, 60) is disposed on the outer surface of the said pair of flat surfaces (44).

5 A coil according to Claim 3 or Claim 4, characterised by the fact that each of the said terminals (27) further includes a second end zone (43) shaped in such a way as to present a further pair of flat surfaces (46) perpendicular to the surfaces (44) of the said first zone (42), the corresponding end (31, 32) of the said conductor (16) being temporarily wound on the said second zone (43) in such a way as to adhere to the said further pair of flat surfaces (46).

6. A coil according to any of Claims 3 to 5, characterised by the fact that each of the said terminals (27) is provided with a notch (47, 48) disposed between the said first zone (42) and the corresponding co-moulded projection (23) for axially and angularly locking the said end (31, 32).

7. A coil according to Claim 6, characterised by the fact that the said notch 47, 48 is of V-shape and is disposed on the terminal 27 connected to the input end 31 on a face parallel to the outer surface of the pair (44) of the said first zone (42), whilst on the terminal (27) connected to the output end (32) it is connected to a face parallel to the inner surface of the pair of the said first zone (42).

8. A coil according to any of Claims 2 to 7, characterised by the fact that the said terminals (27) are cut in correspondence with the said flat portions (59, 60) and are bent towards one another.

9. A method of producing an electrical coil comprising a spool (12) of insulating material and an electrical winding (13), in which the said spool (12) comprises a core (16) and at least one flange (18) co-moulded with a pair of electrical terminals (27) parallel to one another, the said terminals (27) being disposed in a plane parallel to the said first flange 18 and being associated with a pair of ends (31, 32) of the said winding (13), characterised by the following phases: a phase of forming a first zone (42) of the said terminals (27) with a first pair of flat parallel surfaces (44), a phase of winding the said coil (13) including the winding of each end of the said pair (31, 32) on to a terminal of the said pairs (27) in such a way as to obtain a portion (51, 57) at each end which adheres to one of the said flat surfaces (44), a phase of soldering each of the said portions (51, 57) on to the said zone (42) and of cutting the said terminals (27), and a phase of bending the terminals thus cut towards one another.

10. A method according to Claim 9, characterised by the fact that it further includes a phase of forming a second zone (43) of the said terminals (27) with a further pair of flat surfaces (46) perpendicular to the surfaces (44) of the said first pair (42), the said winding of each of the said ends (31, 32) being effected by making a corresponding plurality of turns (49, 58) adhere to the surfaces (46) of the said second zones (43).

11. A method according to Claim 9 or Claim 10, characterised by the fact that the said terminals (27) both project in the same direction and that the said coil is formed by a phase of winding an input end (31) of the said pair on to a terminal (27) of the said pair so as to form a first plurality of adjacent turns (49) in the said direction and at least one portion (51) superposed over the said plurality of turns (49), a phase of winding turns (14) about the said core (16) so as to form a plurality of superposed layers of turns, a reversal of the winding of an output end (32) of the said pair to maintain the turns (14) thus wound around the said core (16) under tension, and a phase of winding the said output end (32) on the other terminal (27) of the said pair so as to form a further plurality of turns (58).

12. A method according to any one of Claims 9 to 11, characterised by the fact that the said soldering is effected on two opposite surfaces (44) of the said first zone of the said two terminals (42) in directions normal to the axis of the said spool (12), and by the fact that the said terminals (27) are cut simultaneously in a direction parallel to the said axis.

13. An electrical coil and associated method of manufacture thereof, substantially as described with reference to the attached drawings.