WO2022069242A1

WO2022069242A1 - Press-in contact and method for producing same

Info

Publication number: WO2022069242A1
Application number: PCT/EP2021/075485
Authority: WO
Inventors: Michael Schmid; Mustafa Akif GÜNCAR; Stephan Jürgen HOFSÄSS
Original assignee: Suba Holding Gmbh + Co. Kg
Priority date: 2020-09-29
Filing date: 2021-09-16
Publication date: 2022-04-07
Also published as: DE102020125453A1; EP4222819A1

Abstract

The invention relates to a press-in contact for being pressed into a hole in a printed circuit board. This press-in contact has a press-in portion (10) which extends from a front end to a rear end and has a front portion (14), a rear portion (18) and a central portion (16) located between the front portion and the rear portion. The central portion (16) is formed by a first flange (27a) and a second flange (27b), the two flanges being separated by a slot (20) extending from a front end (21) to a rear end (22) in the longitudinal direction of the press-in portion (10). The two flanges (27a, 27b) have, on the inner face, an impressed zone (EZ_a, EZ_b) which is produced by means of deformation under pressure and in which the thickness of the press-in portion is reduced in relation to the maximum thickness (d_max). In order to avoid the formation of cracks, the impressed zones (EZ_a, EZ_b) each extend beyond the front end (21) of the slot (20), such that the impressed zones (EZ_a, EZ_b) each have a main portion (23a, 23b) extending laterally along the slot and a front end portion (24a, 24b), the thickness of the end portions (24a, 24b) being smaller than the thickness of the main portions (23a, 23b).

Description

Press-in contact and method for its manufacture

description

The invention relates to a press-in contact for pressing into a hole in a printed circuit board according to the preamble of claim 1 and a method for its production according to the preamble of claim 9.

So-called press-in contacts are widespread in technology. They are used to permanently connect electrical components to a printed circuit board, both electrically and mechanically. Such a press-in contact has a press-in section which can be pressed into a plated-through hole in a printed circuit board by mechanically deforming it. An electrical component usually carries a large number of such press-in contacts which, when the component is mounted on the circuit board, are pressed simultaneously and parallel to one another into holes in the circuit board, with the application of a correspondingly high force. Such press-in contacts are often designed as so-called needle-eye press-in contacts, in which the press-in section has a longitudinal—ie, axial—extending slot, which separates two legs (hereinafter also: first leg and second leg) from one another. The legs are curved outwards, so that the press-in section has a double-convex outer contour in a central section.

DE 198 31 672 B4 shows a needle-eye press-in contact that is currently in use. This has two embossed zones (also: first embossed zone and second embossed zone) in which the thickness of the press-in section is reduced by mechanical deformations. These embossed zones each extend from the slit into a leg, so that part of the edges of the legs on the slit side have a reduced thickness. The embossed zones extend over a certain length of the slot and are essentially in the form of segments of a circle. Due to the shape described in DE 198 31 672 B4 and in particular due to the embossed zones ensures that the press-in section has zones of different hardness, namely a softer section in the front area, a harder section in the middle area and another softer section in the rear area. Press-in contacts with a geometry described in DE 198 31 672 B4 are mostly made of C70250.

The press-in contact of DE 198 31 672 B4 is designed so that the diameter of the hole into which the press-in contact is pressed is approximately 0.6 mm to 1.6 mm. This results in a maximum thickness (that is, material strength) of the press-in contact of approximately 0.4 mm to 0.8 mm. Since the press-in holes in a printed circuit board must have a certain minimum distance from each other, this results in a defined maximum number of press-in contacts per area for a connector. Due to the ongoing miniaturization, however, a larger number of press-in contacts per unit area is now desirable. However, this is only possible by reducing the diameter of the press-in holes. Furthermore, it is often desirable to use materials with an increased current-carrying capacity for such a press-in contact.

It has been found that with a press-fit contact of the type in question, if the material thickness is reduced to below 0.6 mm and/or if certain materials are selected, there is a risk that one of the two legs will tear at the transition between the leg and the front section when pressed in. Among other things, this is due to the fact that neither the press-in section nor the hole into which it is pressed are exactly symmetrical due to tolerances and that the press-in direction is of course not exactly axial either, which means that in the re- one leg is always loaded slightly more than the other leg. This danger increases with decreasing material thickness and less elastic material.

Proceeding from this, the present invention sets itself the task of further developing a generic press-in contact in such a way that it shows a lower tendency to tear, in particular when it has a thickness of 0.6 mm or less. This problem is solved by a press-in contact with the features of claim 1 . A method for its production is specified in claim 9.

According to the invention, the first embossed zone and the second embossed zone each extend beyond the front end of the slit, so that the embossed zones each have a main portion extending laterally along the slit and a front end portion. In this case, the end sections of the embossed zones bear against one another at least in sections, or are only a very small distance apart, in particular a distance of at most 20 μm from one another, with direct abutting against one another being preferred. In this sense one could also say that the two embossed zones are connected to one another via their front end sections.

The front end sections of the embossed zones that are supported on one another provide support for the legs, which compensates for slight asymmetries, as described above, and counteracts tearing of the legs.

As mentioned, the embossed zones, including their front end sections, are produced by plastic deformation of the legs. This means that the embossed zones extend further inwards the deeper they are embossed (ie the smaller their thickness). In order to achieve the above-described abutment of the front end sections, a certain embossing depth of the front end sections is therefore necessary. However, it has been found that if this embossing depth were applied to the entire embossed zones, this would result in a geometry of the main portions of the embossed zones which would not result in ideal behavior of the press-fit portion. In particular, this would lead to excessive rigidity of the legs. Furthermore, the effective width of the slit could become so small that press-fitting of the press-fit portion (where the legs are pushed inward and the width of the slit narrows) is impossible would. Therefore, the thickness of the end sections is less than the thickness of the main sections.

The thickness of the end sections is preferably between 40% and 80%, in particular between 50% and 70%, of the thickness of the main sections.

The thickness of the main portions of the embossed zones is preferably between 60% and 90% of the maximum thickness of the embossed portion.

In order to be able to compensate for manufacturing tolerances, an opening preferably extends through the press-in section at the end of the area formed by the end sections of the embossed zones that faces away from the slot.

It has also been found that the tendency for a leg to tear can be additionally reduced by designing the outer surfaces of the legs to be “less bulbous” than in the press-fit contact of the generic type. Expressed geometrically, this means that the outer surface of each leg has a generally convex portion, the curvature of which has a local minimum, preferably in the middle. The curvature can drop to zero here, which means that in a central section the outer surfaces of the two legs lie in mutually parallel planes.

For the overall behavior of the press-in section, it has turned out to be favorable if the two main sections of the embossed zones extend over the majority of the length of the slot, preferably along at least 70% of the length of the slot. In some embodiments they do not reach the rear end of the slot, in other embodiments the two main sections are sections of a common main section which extends around the rear end of the slot.

The width of the main sections is preferably essentially constant over at least 80% of the length of the embossed zones. The geometry according to the invention is suitable in particular for relatively small press-in contacts with a maximum thickness of 0.6 mm or less, in particular a maximum thickness of 0.4 mm or less.

Particularly suitable materials for the press-fit contact according to the invention are C51900, C70250 and C18080.

The embossed zones are produced by means of two stamps which move relative to one another in the thickness direction and which each have an embossing surface extending from a slot front end to a slot rear end. In order to produce the geometry described above, in a production method according to the invention at least one of the embossing surfaces has a step such that a slot-requiring end region has an increased penetration depth. This preferably applies to both embossing surfaces.

As is fundamentally known in the state of the art, such a press-in contact can be or become completely or partially galvanically coated.

The invention will now be explained in more detail using a preferred exemplary embodiment with reference to the figures. The figures show:

FIG. 1 shows a plan view of the press-in section of a press-in contact according to the invention,

Figure 2 shows a section along the plane A-A in Figure 1,

Figure 3 shows a section along the plane B-B in Figure 1,

Figure 4 shows a section along the plane CC in Figure 1,

FIG. 5 shows a blank of a press-in section, which is formed into the press-in section of FIG. 1, 6 shows a section through the blank of FIG. 5 along the plane DD in FIG. 5 and two punches,

FIG. 7 shows one of the stamps from FIG. 6 in a plan view from direction R in FIG. 6 and

8 shows what is shown in FIG. 6 after the two punches have been moved together, so that the embossed zones are formed in the blank of FIGS. 5 and 6 and the press-in section shown in FIG. 1 is thus formed.

The press-in section 10 shown in FIGS. 1 to 4 is a so-called needle-eye press-in section. It has a top 11 and a bottom 12 (the terms “top” and “bottom” being of course arbitrary) which are substantially planar such that the press-fit portion 10 has a substantially constant maximum thickness D _max . Viewed in the axial direction, the press-in section 10 has three sections, namely a front section 14, a middle section 16 and a rear section 18. Front section 14 and rear section 18 have substantially the same width and the middle section 16 is inward from these sections convex outwardly and formed by two legs 27a, 27b which are separated from each other by means of a through slot 20, as is known in the prior art. This slot 20 extends from a front end 21 to a rear end 22. The press-in section 10 is mirror-symmetrical with respect to the planes of symmetry E1 and E2 drawn in FIGS.

At least part of the outer surface of each leg 27a, 27b is convex overall, that is, each leg 27a, 27b has an outer surface section 28a, 28b that is convex overall. In this case, the convex curvature essentially has a minimum in the middle of the legs. In the exemplary embodiment shown, the curvature in the center of the legs is zero, that is to say the outer surfaces of the two legs 27a, 27b are parallel to one another in a central section. each other. As a result, the two legs 27a, 27b are less “bulky” than is the case in the prior art.

An embossed zone EZ _a , EZ _b extends on each of the two longitudinal sides of the slot 20 . In these embossed zones EZ _a , EZ _b the thickness of the press-in section 10 is reduced compared to the maximum thickness D _max . As is also known in the art, the embossed zones EZ _a , EZ _b do not extend to the rear end 22 of the slot.

According to the invention, however, the embossed zones EZ _a , EZ _b extend beyond the front end 21 of the slot 20, so that they each have a main section 23a, 23b located to the side of the slot 22 and one in front of the front end 21 of the slot 20 have front end portion 24a, 24b. The front end sections 24a, 24b preferably abut one another here, so that they are only separated from one another by a boundary line 25. The thickness d _E 2 of the front end sections 24a, 24b is again reduced compared to the thickness d _Ei of the main sections 23a, 23b, as can be seen from FIGS. 3 and 4, the difference in thickness not having to be so pronounced in practice, as is shown in FIGS. 3 and 4 for clarification. An opening 26 adjoins the front end of the embossed zone.

The main sections 23a, 23b of the embossed zone extend over the major part of the length of the slot 20 and thereby have an almost constant width.

Due to the overall geometry of the press-in section 10, that is, through the somewhat flattened, i.e. less strongly curved, legs 27a, 27b and through the pivot point formed by the two front end sections 24a, 24b of the embossed zones, which is relatively far away from the front end of the press-in Section 10 is located, compared to the press-in contact of the prior art, there are reduced forces in the front areas of the legs 27a, 27b when the press-fit portion 10 is press-fitted into the hole of a circuit board, and thus the risk of a crack in a leg is reduced.

With reference to Figures 5 to 8, the manufacturing method according to the invention of the press-in section 10 just described will now be described:

In a preceding work step, which consists of several punching steps or at least includes them, a blank 30 is formed from a metal strip. This has two legs 47a, 47b and an exit slot 40 extending between these legs 47a, 47b. The outer contour of the legs 47a, 47b of the blank 30 already corresponds to the outer contour of the finished press-in section 10. It is important that the length U of the exit slot is greater is than the length l _s of the slit 20.

As shown in FIG. 6, in a production step, which is generally the last production step, the embossed zones 23a, 23b; 24a, 24b are stamped into the blank 30, that is to say into the legs of the blank 47a, 47b. The two stamps 50 used for this purpose are symmetrical, generally identical to one another.

Each punch 50 has an embossing surface 52 with a main portion 54 and a slot front end portion 56. The total length of the embossing surfaces 52 is less than the length L _Ä of the exit slot 40 and the embossing surfaces 52 extend neither to its front nor to its rear end. The front end areas 56a of the slit are offset from their respective main area 54 in the embossing direction, so that the end areas 56 in front of the slit have a greater embossing depth than the main areas 54, which results in the lower thickness of the front end sections 24a, 24b of the embossed zones _EZa , EZb . Since the material of the blank naturally "has to go somewhere", it also follows that the front end sections of the embossed zones 24a, 24b extend further inwards, namely until they abut one another, as a result of which the shortening of the slot 20 results without affecting the main portions of the embossed zones. As can easily be seen by comparing FIGS. 1 and 5, the opening 26 is the front end area of the exit slot 40, so that the geometry described could also be expressed by saying that the front end sections 24a, 24b of the embossed zones EZ _a , EZ _b so far into the exit slot 40 that they subdivide it into a main section (namely the slot 20) and a front end section (namely the opening 26). However, a different definition was chosen in the present application and in this the slot 20 of the finished press-in section 10 is shortened compared to the exit slot 40 of the blank 30 .

Reference List

10 press-in section

11 top

12 bottom

14 front section

16 middle section

18 rear section

20 slot

21 front end

22 rear end

23a,b Main portion of an embossed zone

24a,b front end portion of an embossed zone

25 boundary line

26 breakthrough

27a, b thighs

28a,b convex outer surface section

29a, b central area of the convex outer surface section

30 blank

34 front section

36 middle section

38 posterior section

40 exit slot

50 stamps

52 embossing area

54 main area

56 slot front end area

EZ _a first stamped zone

EZb second embossed zone d _max maximum thickness d _E1 thickness of the main portion of an embossed zone d _E2 thickness of the leading end portion of an embossed zone

IA length of exit slot

Is length of the slit

Claims

patent claims

1. Press-in contact for press-fitting into a hole of a printed circuit board, comprising: a press-in section (10) extending from a front end to a rear end and having a front section (14), a rear section (18) and a between central section (16) located in the front section and rear section, the central section (16) being formed by a first leg (27a) and a second leg (27b) which are each curved outwards and which each have an outer surface , first leg (27a) and second leg (27b) are separated by a slot (20) extending in the longitudinal direction of the press-in section (10) from a front end (21) to a rear end (22), the maximum thickness (d _max ) of the front section, rear section and middle section is essentially the same, the first leg (27a) on the inside has a first embossed zone (EZ _a ) produced by pressurized deformation, in d the thickness of the press-in section is reduced compared to the maximum thickness (d _max ), and the second leg (27b) on the inside has a second embossed zone (EZ _b ) produced by pressurized deformation, in which the thickness of the press-in section is opposite of the maximum thickness (d _max ), characterized in that the first embossed zone (EZ _a ) and the second embossed zone (EZ _b ) each extend beyond the front end (21) of the slot (20). , so that the embossed zones (EZ _a , EZ _b ) each have a main section (23a, 23b) extending laterally along the slot and a front end section (24a, 24b), the thickness of the end sections (24a, 24b) being smaller than the thickness of the main sections (23a, 23b).

2. Press-in contact according to claim 1, characterized in that the end sections (24a, 24b) of the embossed zones (EZ _a , EZ _b ) rest against one another at least in sections or have a minimum distance from one another of 20 μm or less amounts to.

3. Press-in contact according to claim 2, characterized in that an opening (26) extends through the press-in section (10) at the end of the area formed by the end sections (24a, 24b) facing away from the slot (20).

4. Press-in contact according to any one of the preceding claims, characterized in that the outer surface of each leg (27a, 27b) has an overall convex portion, the curvature of which has a local minimum.

5. Press-in contact according to one of the preceding claims, characterized in that the embossed zones (EZ _a , EZ _b ) end in front of the rear end (22) of the slot (20).

6. Press-in contact according to one of the preceding claims, characterized in that the press-in section (10) has a maximum thickness (d _max ) of 0.6 mm or less, in particular a maximum thickness of 0.4 mm or less.

7. Press-in contact according to one of the preceding claims, characterized in that the press-in section (10) is mirror-symmetrical with respect to two mutually perpendicular planes of symmetry (E1) and (E2) extending in the longitudinal direction.

8. Press-in contact according to one of the preceding claims, characterized in that it consists of C51900, C70250 or C18080 Method for producing a press-in contact according to one of the preceding claims with the following steps:

Providing a blank (30) comprising: a front end to a rear end extending press-in portion having a front portion, a rear portion, and a center portion located between the front portion and rear portion, the center portion being defined by a first leg (47a) and a second leg (47b), each of which is outwardly curved and each of which has an outer surface, first leg (47a) and second leg (47b) are formed by a longitudinal direction of the press-in portion from a front end to a rear end extending exit slot (40) are separated, and the maximum thickness (d _max ) of the front section, rear section and middle section is essentially the same,

Embossing of the embossed zones (EZ _a , EZ _b ) by means of two stamps (50) which move relative to one another in the direction of thickness and which each have an embossing surface (52) extending from a slot front end to a slot rear end, characterized in that that at least one of the embossing surfaces (52) has a step such that a slot-requiring end area (56) has an increased penetration depth.