Winding post for connecting to a coil body of an electromagnetic coil

Abstract

The invention relates to a winding post (10) for connecting to a coil body of an electromagnetic coil, wherein the winding post (10) has a rod-like post body (11), formed from a piece of wire, having a polygonal cross section or round cross section, and the post body (11) is provided on its surface (13, 14), in the longitudinal direction (16), with a serial arrangement (15) of surface elements that extend transversely to the longitudinal direction (16) and are at least partially in the form of recesses (17), wherein the recesses (17) extend in the circumferential direction only around a part of the circumference of the post body (11), wherein the recesses (17) extend in the circumferential direction between adjacent longitudinal edges (18, 19) of the polygonal cross section such that the recesses (17) are spaced apart from the longitudinal edges (18, 19), or extend around a part of the circumference of the round cross section.

Description

[0001] The present invention relates to a winding post for connection to a coil body of an electromagnetic coil.

[0002] Winding posts of the type mentioned above serve to form connection devices on electromagnetic coils, such that the connection devices establish an electrically conductive connection between the coil wire of the electromagnetic coil and a contact surface of a printed circuit board or the like. To connect the coil wire to the winding post, a winding section of the winding post, which is anchored in the coil body by an anchoring section, is wound with one end of the coil wire arranged on the coil body. To secure this connection, a solder connection is usually additionally established between the coil wire and the winding post.

[0003] In order to improve the anchoring of the anchoring section in the plastic material of the coil body and the fixation of the coil wire end on the winding section of the winding post, the known winding posts are provided with a structure on their surface which consists of a row arrangement of depressions extending transversely to the longitudinal direction.

[0004] For example, DE 20 2017 104 818 U1 discloses a winding post which is rod-shaped and is provided on two oppositely arranged surfaces, both in an anchoring section and in a winding section, with grooves running transversely to the longitudinal direction of the winding post, which extend over the entire width of the rod-shaped post body into the opposite longitudinal edges.

[0005] Tests have now shown that the grooves extending into the longitudinal edges do indeed provide the desired high pull-out forces, which make it impossible for the winding post to be released from its anchorage on the coil former without considerable effort, and thus ensure a reliable connection between the winding post and the coil former, and also enable good mechanical fixing of the coil wire end to the rod-shaped post body. However, the grooves extending into the longitudinal edges of the polygonal cross-section induce a notch effect on the longitudinal edges, so that if the winding post is bent, as is sometimes necessary to connect the winding post to conductor tracks on a printed circuit board or to the coil former, the winding post may break, or during the winding of the wire end in conjunction with the wire tension, a wire may break.

[0006] JP H08 255708 A discloses a winding post for connection to a coil former of an electromagnetic coil, wherein the winding post has a rod-shaped post body with a polygonal cross-section and the post body is provided on its surface in the longitudinal direction with a row arrangement of surface elements extending transversely to the longitudinal direction and designed as zigzag-shaped or wave-shaped depressions. The depressions extend only over one side of the post body, wherein the depressions extend between adjacent longitudinal edges such that the depressions are spaced from the longitudinal edges. The depressions serve to create a gap between the post body and the coil wire in order to achieve a good solder connection between the post body and the coil wire.Furthermore, the post body has notches extending transversely to the longitudinal direction on the longitudinal edges, which serve to improve the fixation of a coil wire end of a coil wire of the electromagnetic coil on a winding section of the winding post.

[0007] EP 0 878 809 A2 discloses a winding post with an angled portion, wherein the winding post has a rod-shaped post body formed from a wire segment. Furthermore, the post body has longitudinal ridges on its surface, which are intended to prevent a coil wire of an electromagnetic coil from slipping off free ends of the post body.

[0008] DE 19 49 413 A1 discloses a winding post formed from a threaded wire section, wherein a coil wire of an electromagnetic coil can be fixed in thread grooves of the thread until soldering.

[0009] The present invention is therefore based on the object of proposing a winding post which, compared to the known winding post, has a higher component safety and reduces the risk of wire breakage.

[0010] To achieve this object, the winding post according to the invention has the features of claim 1.

[0011] The winding post according to the invention for connection to a coil body of an electromagnetic coil has a rod-shaped post body with a polygonal or round cross-section formed from a wire section, and the post body is provided on its surface in the longitudinal direction with a row arrangement of surface elements extending transversely to the longitudinal direction and at least partially formed as a depression, wherein the depressions extend in the circumferential direction only over a partial circumference of the post body, wherein the depressions extend in the circumferential direction between adjacent longitudinal edges of the polygonal cross-section in such a way that the depressions are spaced from the longitudinal edges, or extend over a partial circumference of the round cross-section, wherein the depressions are arranged in mutually opposite surfaces of the post body.

[0012] In the winding post designed according to the invention, the extent of the recesses is limited to the space formed between the adjacent longitudinal edges of the polygonal cross-section, without the recesses extending into the longitudinal edges of the polygonal cross-section. Thus, the longitudinal edges themselves, where maximum compressive stress in the polygonal cross-section or wire tension occurs as a result of the deflection of the coil wire during a winding process, are exempt from the notch effect induced by the recesses. This significantly reduces the risk of component failure during a winding process or when the winding post bends.At the same time, the desired anchoring effect of the recesses in the anchoring section of the winding post is impaired as little as possible by the fact that, as long as the recesses do not penetrate into the longitudinal edges, the width of the surface between the longitudinal edges can be used as much as possible to form the recesses.

[0013] Depending on the respective contacting situation, the rod-shaped post body can have a straight or single or multiple curved or angled longitudinal extension.

[0014] The term "polygonal cross-section" is to be understood in the context of the invention as meaning that the surface of the post body is formed from several partial surfaces that merge into one another at longitudinal edges. These partial surfaces may, in turn, have a flat or at least partially concave or convex surface, with the longitudinal edges in practice having a radius. In contrast, the "round cross-section" has a circular or approximately circular circumference.

[0015] In addition to the depressions, the surface elements can also have elevations in certain areas.

[0016] Because the recesses are arranged on opposing surfaces of the post body, a relatively shallow recess depth, particularly in the case of small and very small diameters of the wire section used to form the wound post, can be compensated for by arranging the recesses on multiple or even all sides. If necessary, not only selected opposing surfaces, but at most all surfaces can be provided with recesses.

[0017] If the recesses according to a preferred embodiment of the winding post have a continuously decreasing depth towards their longitudinal ends, a notch effect possibly induced by the longitudinal ends of the recesses can be reduced to a minimum, so that the advantageous, component safety-enhancing effect of the inventive design of the winding post can be increased even further.

[0018] A further increase of the advantageous effect is possible if the depressions have concave flanks that rise from the base of the depression to the surface.

[0019] Preferably, the flanks are convex in a transition to the surface so that, unlike a sharp-edged transition to the surface, possible stress peaks in the surface can be avoided.

[0020] In a particularly preferred embodiment of the winding post, the depressions in the surface are frame-shaped, in particular annular, such that the depressions surround a central region formed by the surface of the post body, so that the anchoring effect can be increased even further compared to the conventional grooves extending transversely to the longitudinal direction of the post body.

[0021] If the post body is designed to be electrically conductive, it is possible to dispense with the formation of an electrically conductive coating on the post body.

[0022] Alternatively, it is also possible to dispense with an electrically conductive material for the formation of the post body and instead to provide the post body with an electrically conductive coating.

[0023] Preferred embodiments of the winding post are explained in more detail below with reference to the drawings.

[0024] They show: Fig. 1 a winding post according to a first embodiment in an isometric view; Fig. 2 the in Fig. 1 shown winding post in side view; Fig. 3 a cross-sectional view of the Fig. 2 shown winding post according to section line III-III in Fig. 2 ; Fig. 4 another embodiment of a winding post in isometric view; Fig. 5 a cross-sectional view of the Fig. 4 shown winding post according to section line VV in Fig. 4 ; Fig. 6 a partial sectional view of the Fig. 4 shown winding post according to section line VI-VI in Fig. 5 .

[0025] Fig. 1 shows a winding post 10, which has a rod-shaped post body 11 extending in a straight line here with a particularly in Fig. 3 shown polygon cross-section 12.

[0026] How Fig. 1 As shown, the post body 11 is provided on two opposing surfaces 13, 14 with a row arrangement 15 of recesses 17. The recesses 17 extend transversely to the longitudinal direction 16 at a distance a from adjacent longitudinal edges 18, 19 delimiting the surfaces 13, 14 and, in the present case, are annular in shape, such that the recesses 17 surround a central region 20 formed by the surface 13.

[0027] How Fig. 3 As shown, the depressions 17 have a continuously decreasing depth t 1 towards their edges 21, 22, and in particular towards the longitudinal edges 18, 19. Furthermore, the depressions 17 have concave flanks 24, 25 rising from a depression base 23 to the edges 21, 22 of the surface 13. In the illustrated embodiment, the flanks are also convex in a transition 26 to the surface 13 or 14.

[0028] In the Fig. 1 - 3 In the illustrated embodiment of the connection post 10, the polygonal cross-section 12, which is essentially square here, can have an edge length 1 of 0.5 mm. The recesses 17 on the opposing surfaces 13, 14 have a center-to-center distance m in the longitudinal direction 16 of the post body 11, which in the present case corresponds to the edge length 1. Preferably, the depth t 1 of the recesses is selected such that it is less than 0.05 mm, whereby, given the proportions of the presently illustrated embodiment, a depth of 0.03 to 0.04 mm has proven particularly advantageous for achieving the desired high extraction forces. The edge distance a is selected to be approximately 0.1 mm, on the order of magnitude of the diameter of the central region 20.

[0029] Tests have shown that, based on the selected proportions of the polygon cross-section, a deviation of up to 20% from the above-mentioned size specifications is possible without impairing the intended beneficial effects.

[0030] In the Fig. 4 und 5 In a further embodiment, a winding post 40 is shown which has a rod-shaped post body 41 with a round cross-section 42, which in the present case has a circular circumference 43, wherein depressions 44, which are located in a row arrangement 45 on a surface 46 of the post body 41, extend only over a partial circumference 47 of the round cross-section 42.

[0031] In the illustrated embodiment, the recesses 44 have a continuously decreasing depth t 2 towards their longitudinal ends 48, 49.

[0032] As in particular Fig. 6As shown, the depressions 44 have concave flanks 51, 52 rising from a depression base 50 to the surface 46. Furthermore, the flanks 51, 52 are convex in a transition 53 to the surface 46.

[0033] In the present case, the post body 41 of the wrap-around post 40 has proportions comparable in size to the post body 11 of the wrap-around post 10.

[0034] In particular, the post body 41 can also be provided with the recesses 17 shown on the post body 11 of the winding post 10, wherein, regardless of the respective design of the recesses, the recesses can extend in different partial circumferences, as long as the recesses arranged in different partial circumferences are not designed to merge continuously into one another.

Claims

1. A wrapping post (10, 40) for connection to a coil body of an electromagnetic coil, the wrapping post (10, 40) having a rod-shaped post body (11, 41) which is formed from a wire part and has a polygonal cross section (12) or circular cross section (42), and the post body (11, 41) being provided with a row arrangement (15, 45) of surface elements on its surface (13, 14, 46) in the longitudinal direction (16), the surface elements extending transversely to the longitudinal direction (16) and being at least partly formed as recesses (17, 44), the recesses (17, 44) only extending over a partial circumference (47) of the post body (11, 41) in the circumferential direction, wherein the recesses (17, 44) extend in the circumferential direction between adjacent longitudinal edges (18, 19) of the polygonal cross section (12) in such a manner that the recesses (17) are spaced apart from the longitudinal edges (18, 19) or extend over a partial circumference (47) of the circular cross section (42), the recesses (17) being disposed in opposite surfaces (13, 14) of the post body (11).

2. The wrapping post according to claim 1, characterized in that towards the longitudinal edges (18, 19), the recesses (17) have a continuously decreasing depth t1.

3. The wrapping post according to claim 1 or 2, characterized in that the recesses (17, 44) have concave flanks (24, 25, 51, 52) rising from a recess bottom (23, 50) to the surface (13, 14, 46).

4. The wrapping post according to claim 3, characterized in that in a transition (26, 53) to the surface (13, 14, 46), the flanks (24, 25, 51, 52) are convex.

5. The wrapping post according to any one of the preceding claims, characterized in that the recesses (17) in the surface (13, 14) are frame-shaped, in particular annular, in such a manner that the recesses (17) surround a central area (20) formed by the surface (13, 14) of the post body (11).

6. The wrapping post according to any one of the preceding claims, characterized in that the post body (11, 41) is electroconductive.

7. The wrapping post according to any one of the preceding claims, characterized in that the post body (11, 41) is provided with an electroconductive coating.

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