Electrical fuse element

Abstract

An electric fuse element for arrangement on a printed circuit board is specified. The fuse element is formed as an SMD component and has a cuboidal insulating housing, two contact elements for electrical connection to the printed circuit board and at least one support element. The contact elements are arranged on a bottom side of the insulating housing, wherein the contact elements emerge at the bottom side of the insulating housing by way of a subregion, which has a contact area on the end side. The emerging subregion having the contact areas is of angled form.

Claims

1. An electric fuse element for use on a printed circuit board as a surface mounted device (SMD) component, the electric fuse element comprising: an insulating housing having a bottom side; two contact elements for electrical connection to the printed circuit board, said contact elements each emerge from said housing at said bottom side of said insulating housing aligned along a common axis, and each has a contact area on an end side, and said contact area is of angled form; and at least one support element, disposed on said bottom side and having a support area for support on the printed circuit board; said contact areas and said support area being disposed within a common plane, each said contact area being a flat area, said contact areas being bent in opposing directions relative to one another and said contact areas projecting laterally beyond opposite sides of said insulated housing in a direction transverse to said common axis.

2. The electric fuse element according to claim 1, wherein said contact area is angled at 90.

3. The electric fuse element according to claim 1, wherein the electric fuse element is a fusible link.

4. The electric fuse element according to claim 3, wherein: the fusible link has a bent sheet-metal part; and said bent sheet-metal part includes said two contact elements and defines a fuse region with a fusible conductor.

5. The electric fuse element according to claim 1, wherein said contact areas project laterally beyond said said main sides at most by half of said narrow side width.

6. The electric fuse element according to claim 1, wherein said top side has a planar surface.

7. The electric fuse element according to claim 1, wherein said contact elements are made from a metal and are at least partly refined.

8. The electric fuse element according to claim 1, wherein said insulating housing has a plastic capable of reflow.

9. An electric fuse element for use on a printed circuit board as a surface mounted device (SMD) component, the electric fuse element comprising: an insulating housing having a cuboidal shape with a bottom side, a top side, two opposite main sides, and two opposite narrow sides, said two opposite main sides and said two opposite narrow sides extending between said bottom side and said top side in a vertical direction and having a common height, said narrow sides having a width extending in a transverse direction (y-direction) and said main sides having a width extending in a longitudinal direction (x-direction), said width of said narrow sides being less than said width of said main sides and said height being greater than said width of said narrow side; two contact elements for electrical connection to the printed circuit board, said contact elements each emerge at said bottom side of said insulating housing by way of a subregion, and each has a contact area on an end side, and said contact area is of angled form; and at least one support element, disposed on said bottom side and having a support area for support on the printed circuit board; said contact areas and said support area being disposed within a common plane, each said contact area being a flat area, said support area for being disposed on the printed circuit board and orientating said insulating housing and the vertical direction orthogonally to the printed circuit board; said contact areas projecting laterally beyond said insulating housing in the transverse direction.

10. An electric fuse element for use on a printed circuit board as a surface mounted device (SMD) component, the electric fuse element comprising: an insulating housing having a cuboidal shape with a bottom side, a top side, two opposite main sides, and two opposite narrow sides, said two opposite main sides and said two opposite narrow sides extending between said bottom side and said top side and having a common height, said narrow sides having a narrow side width orthogonal to said height and said main sides having a main side width orthogonal to said height, said width of said narrow sides being less than said width of said main sides; two contact elements for electrical connection to the printed circuit board, said contact elements each emerging from said insulating housing at said bottom side of said insulating housing, and each has a contact area on an end side, and said contact area is of angled form; and at least one support element, disposed on said bottom side and having a support area for support on the printed circuit board; said contact areas and said support area being disposed within a common plane, each said contact area being a flat area, said support area for being disposed on the printed circuit board and orientating said main sides and said narrow sides orthogonally to the printed circuit board; said contact areas projecting in opposing directions to one another laterally beyond said main sides in the transverse direction.

Description

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWING

(1) An exemplary embodiment of the invention will be explained in more detail below with reference to the figures. These each show, partly in highly simplified representations:

(2) FIG. 1 a perspective view of an electric fuse element,

(3) FIG. 2 a side view of the electric fuse element arranged on a printed circuit board and

(4) FIG. 3 a side view of the fuse element formed to form a fusible link.

DESCRIPTION OF THE INVENTION

(5) In the figures, identically acting parts are illustrated with the same reference designitions.

(6) FIG. 1 illustrates a transverse view of an electric fuse element 2 for arrangement on a printed circuit board 3 (illustrated in FIG. 2), for example a PCB. PCB is understood in the present case to mean, in particular, a printed circuit and/or a circuit board. A printed circuit is understood specifically to mean a circuit on a printed circuit board in which the conductor tracks are printed on a carrier material of the printed circuit board, for example. A plastic, for example, serves as carrier material. In the exemplary embodiment, the fuse element 2 is formed as a surface-mount-device component (SMD component).

(7) Furthermore, the fuse element 2 has a cuboidal insulating housing 4 having two opposite main sides 6 (one main side cannot be seen in FIG. 1), a bottom side 8 and a top side 10 opposite the bottom side 8. To form the cuboidal shape, the insulating housing 4 also has two opposite narrow sides 12. The two opposite main sides 6 and the narrow sides 12 extending between said bottom side 8 and the top side 10 in a vertical direction and having a common height H. The narrow sides 12 have a width B.sub.S that extends in a transverse direction (y-direction) and the main sides 6 have a width B.sub.H that extends in a longitudinal direction (x-direction). In the exemplary embodiment, the insulating housing 4 has a plastic capable of reflow, for example polyetherketone or a liquid crystal polymer (LCP). This makes it possible, in particular, to arrange the fuse element 2 on the printed circuit board 3 by means of standard methods.

(8) In the exemplary embodiment, the width B.sub.S of the narrow sides 12 has a lower value than the width B.sub.H of the main sides 6.

(9) In the exemplary embodiment, the width B.sub.S of the narrow sides corresponds to an insulating housing width B.sub.G. In the exemplary embodiment, the fuse element 2 is formed as a blade-type fuse as a result.

(10) The fuse element 2 has two contact elements 14 for electrical connection to the printed circuit board 3. The contact elements 14 emerge at the bottom side 8 of the insulating housing 4 out of said insulating housing and have contact areas 16, which are angled at a right angle. In this case, the contact areas 16 are each angled in opposite directions to a respective main side 6. The contact elements 14 are part of a bent sheet-metal part 22 (illustrated in FIG. 3).

(11) In a state arranged on the printed circuit board 3, the fuse element 2 has an alignment oriented orthogonally to the printed circuit board 3. In other words: the fuse element 2 is arranged, for example soldered, upright onto the printed circuit board 3 so that the top side 10 is oriented parallel to the printed circuit board 3.

(12) For reliable contact-making, the contact elements 14 are made from a metal, for example copper or zinc, and are additionally at least partly refined, for example tin-coated or silver-coated. At least partly refined is understood in the present case to mean that at least the contact areas 16 are, for example, tin-coated and thus able to be soldered onto the printed circuit board 3, for example, by means of a reflow method.

(13) In the exemplary embodiment, the top side 10 of the fuse element 2 has a planar surface. A planar surface is understood in the present case to mean a flat surface, which does not have, in particular, any dips and/or grooves, for example.

(14) On account of the planar surface, in particular, population of the printed circuit board 3 with the fuse element 2 is made possible, in the manner of a pick-and-place method. In the case of such a pick-and-place method, the individual components are suctioned by means of a suction nozzle, which is arranged, for example, on a robot arm controlled by a computer, and arranged on the printed circuit board 3. To take up the fuse element 2 by means of the suction nozzle, a planar surface of the fuse element 2 of this kind is essential.

(15) In the exemplary embodiment, the fuse element 2 furthermore has a support element 18 having a support area 20. The support element 18 and the support area 20 serve to support the arranged fuse element 2 on the printed circuit board 3 so that the contact elements 14 preferably serve for making electrical contact and do not also have to bear the weight of the fuse element 2. In addition, the fuse element has advantages with respect to vibration resistance as a result.

(16) FIG. 2 illustrates a side view of the electric fuse element 2. FIG. 2 is, in particular, not subject to any scale. The components shown serve exclusively for graphical illustration of an exemplary embodiment of the invention.

(17) In the exemplary embodiment, the contact areas 16 and the support area 20 are arranged within a plane E. This guarantees support of the fuse element 2 on the printed circuit board 3.

(18) Furthermore, in the exemplary embodiment, the contact areas 16 project laterally beyond the insulating housing 4 at most by half of the insulating housing width B.sub.G. As an alternative, the contact areas 16 project laterally beyond the insulating housing at most by a value of the insulating housing width B.sub.G.

(19) This configuration is based, in particular, on an increase in stability, in particular with respect to arising lateral forces, in comparison to a configuration in which, for example, the contact elements 14 do not project laterally beyond the insulating housing.

(20) In the exemplary embodiment, the fuse element 2 is formed as a fusible link.

(21) FIG. 3 shows such a formation of the fuse element 2. The fuse element 2 has to this end a bent sheet-metal part 22, which has the contact elements 14 and the contact areas 16. The bent sheet-metal part 22 also has a fuse region 24 having a fusible conductor 26. The fuse region 24 connects the two contact elements 14 to one another within the insulating housing 4. In the exemplary embodiment, the bent sheet-metal part has a metal, for example zinc, and is at least partly refined.

(22) In the following text, the functioning of a fusible link of this kind is briefly dealt with once more:

(23) The fusible link is usually arranged in a circuit that is to be protected so that the current flowing through the circuit also flows through the fusible link. When a current threshold value is exceeded, for example due to a short circuit in the circuit, the fusible conductor 26 of the fuse region 24 melts on account of the arising thermal loading. As a result of this, the circuit is opened and is consequently free of current. Further lines, components and/or devices connected to the circuit are consequently protected against an overcurrent.

(24) In the exemplary embodiment, the fusible conductor 26 is of tapered form. The tapering is correlated progressively with the current threshold value (current value from which the fusible link is triggered). That is to say, the thicker the fusible conductor 26, the greater the current threshold value at which the fusible conductor 26 melts. As a result, a simple realization of fusible links for different circuits that are to be protected and for different current threshold values is achieved.

LIST OF REFERENCE DESIGNATIONS

(25) 2 Electric fuse element 3 Printed circuit board 4 Insulating housing 6 Main sides 8 Bottom sides 10 Top side 12 Narrow side 14 Contact element 16 Contact area 18 Support element 20 Support area 22 Bent sheet-metal part 24 Fuse region 26 Fusible conductor B.sub.G Insulating housing width B.sub.H Width of the main side B.sub.S Width of the narrow side E Plane