Capacitor and arrangement with circuit board and capacitor

Abstract

The present invention relates to a capacitor comprising a winding element arranged in a housing (1), a mounting plate (11) comprising a non-conductive material and attached to the housing (1), and a metal element (7) arranged between the housing (1) and the mounting plate (11), wherein the metal element (7) comprises a projecting part (9a, 9b) extending through the mounting plate (11).

Description

[0001] The present invention relates to a capacitor. In particular, the present invention relates to a capacitor that is to be mounted on a printed circuit board (PCB) by surface mounting (SMD).

[0002] Standard SMD capacitors are often poorly mechanically attached to a printed circuit board using their leads. Furthermore, heat dissipation from the SMD capacitor to the circuit board is limited by the physical dimensions of the leads.

[0003] Therefore, there is a need for an improved surface-mount capacitor that overcomes at least one of the disadvantages described above. It is an object of the present invention to provide such a capacitor.

[0004] This problem is solved by the subject matter of claim 1.

[0005] A capacitor is provided comprising a winding element arranged in a housing, a mounting plate comprising a non-conductive material and attached to the housing, and a metal element arranged between the housing and the mounting plate, the metal element having a protruding portion extending through the mounting plate. The capacitor may additionally include a sealing element.

[0006] By adding the metal element between the capacitor housing and the mounting plate, the disadvantages of SMD capacitors described above can be overcome. The metal element can be thermally contacted with the housing. This allows heat absorbed by the housing to be transferred to the circuit board via the metal element during surface mounting, such as reflow soldering. This enables heat to be applied very quickly to the circuit board's solder pads during reflow soldering, thus accelerating the soldering process, as heat can be applied not only from the circuit board itself but also from heat absorbed by the housing.Furthermore, during normal capacitor operation, the metal element can remain thermally connected to the housing in such a way that the heat generated by the winding element within the housing can be transferred to the circuit board via the metal element. Thus, the addition of the metal element allows the circuit board to be used as a heat sink. For example, ripple currents in the winding element can generate heat. The metal element can contribute to the thermal management of the capacitor by dissipating heat away from the housing.

[0007] The metal element can also contribute to improved mechanical mounting of the capacitor to the circuit board. In particular, the metal element can provide one or more mechanical contacts that can be attached to the circuit board, for example, by soldering.

[0008] The mounting plate can be a small plate with dimensions similar to those of the enclosure. The enclosure can be attached to the mounting plate. The mounting plate can be designed to be attached to a printed circuit board during surface mounting.

[0009] The protruding part of the metal element can extend in one direction away from the winding element above the mounting plate.

[0010] The protruding part of the metal element can be designed to be attached to a printed circuit board (PCB) when the capacitor is surface-mounted to the PCB. In particular, the protruding part of the metal element can form a mechanical contact that can be attached to a solder pad on the PCB by soldering.

[0011] The metal element can be configured to transfer heat from the housing to the printed circuit board (PCB). Accordingly, the metal element can accelerate the soldering process during surface mounting, as heat absorbed by the housing is effectively transferred to the solder pad. Furthermore, during normal capacitor operation, the metal element can facilitate heat transfer from the housing to the PCB, allowing the PCB to act as a heat sink.

[0012] The winding element can include two terminals, forming two contacts designed for surface mounting on the printed circuit board (PCB). These two terminals can provide electrical contact between the winding element and the PCB. Additionally, the two terminals can also be thermally and mechanically connected to the PCB.

[0013] The metal element can provide two additional mechanical contacts designed for surface mounting. These additional mechanical contacts can be formed by the protruding portion of the metal element. The contacts provided by the metal element are preferably not galvanically connected to the winding element. The contacts provided by the metal element can be mechanically and thermally connected to the printed circuit board (PCB). Thus, the metal element can contribute to improved mechanical and thermal connectivity between the PCB and the capacitor.

[0014] The connections of the winding element can protrude through a recess in the mounting plate.

[0015] The metal element can be clamped between the mounting plate and the housing. The metal element can be attached to the housing purely mechanically. In particular, no adhesive or external plastic parts are required to attach the metal element to the housing. Instead, the metal element can be attached to the housing using the same mechanical means as a sealing element that closes the housing from the rest of the housing. In particular, the metal element can be attached to the housing using a bead and a roll. The bead and roll are required in any case for sealing the housing with the sealing element, so no additional means are needed to attach the metal element. The metal element can be positioned between the sealing element and the mounting plate. In particular, the metal element can abut the sealing element, which is located at the bottom of the housing.The metal element also rests against the mounting plate.

[0016] The metal element can comprise an annular base body. The annular shape of the base body can define an opening through which the connections of the winding element can pass. The opening in the base body can be large enough to allow the annular base body to be combined with a wide variety of winding elements and sealing elements, without restricting the position and size of the connections.

[0017] The protruding part of the metal element can be a pin. The pin can be bent before or after it is passed through an opening in the mounting plate. Bending the pin further secures the metal element to the mounting plate, thus preventing axial movement of the metal element relative to the mounting plate.

[0018] The pin can be bent to form a surface parallel to a mounting surface of the capacitor. The capacitor's mounting surface can be a lower surface of the mounting plate, facing away from the winding element. The capacitor's mounting surface can be designed to rest against a printed circuit board if the capacitor is surface-mounted to the board.

[0019] The metal element can be a stamped metal sheet, with the protruding part being formed using stamping technology.

[0020] The metal element is preferably not galvanically connected to the winding element.

[0021] The capacitor may include a sealing element that seals the housing. The metal element may be positioned between the sealing element and the mounting plate.

[0022] The present invention further relates to an arrangement comprising a printed circuit board and the capacitor described above, wherein the capacitor is attached to the printed circuit board by means of surface mounting.

[0023] The following preferred embodiments of the present invention are described with reference to the drawings. Fig. Figure 1 shows an exploded view of a housing, a sealing element and a metal element of a capacitor. The Fig. 2 and Fig. Figure 3 shows perspective views of a capacitor according to a first embodiment during various stages of an assembly process; Fig. Figure 4 shows the capacitor according to the first embodiment after completion of the assembly process; the Fig. 5, Fig. 6 and Fig. Figure 7 shows a metal element according to a first embodiment before bending over a protruding part; the Fig. 8, Fig. 9 and Fig. Figure 10 shows a metal element according to the first embodiment after bending the protruding part; the Fig. 11 and Fig. Figure 12 shows a capacitor according to a second embodiment during various stages of an assembly process; and the Fig. 13 and Fig. Figure 14 shows the capacitor of the second embodiment after completion of the assembly process.

[0024] Fig. 1 shows a case 1 , a sealing element 5 and a metal element 7 of a capacitor in an exploded view.

[0025] The capacitor includes a winding element located inside the housing. 1 is arranged. The housing 1 It's an aluminum can. The casing 1 is cylindrical. The winding element includes two connections. 2a , 2b , which are from the casing 1stand out. The connections 2a , 2b The winding element has electrical connections designed to be connected to the printed circuit board during surface mounting.

[0026] The case 1 has a first end 3 and a second ending 4 The first end 3 of the case 1 is open. The wires which connect 2a , 2b The winding element protrudes from the first end. 3 of the case 1 out. The second ending 4 of the case 1 is opposite the first end 3 arranged. The second end 4 is closed. This document contains the first end. 3 also referred to as the lower end and is the second end 4 is also referred to as the upper end.

[0027] The capacitor also includes a sealing element. 5, which is designed to be the case 1 to seal. In particular, the sealing element 5 set up to be the lower end 3 of the case 1 to seal. The sealing element 5 It includes a non-conductive material, for example, rubber. Rubber is used as the material for the sealing element. 5 especially suitable, as rubber has high elasticity and therefore the casing 1 can reliably seal. The sealing element 5 includes two holes 6 , which are set up to connect 2a , 2b to accommodate the winding element. The sealing element 5 is from the lower end 3 of the case 1 here into the case 1 used.

[0028] The capacitor includes the metal element 7 , which is located under the sealing element 5 is arranged in a direction pointing away from the winding element. The metal element7 has a ring-shaped base body 8 and comprises two preceding parts 9a , 9b .

[0029] Further details of the metal element 7 will be in each of the Fig. 4, Fig. 5 and Fig. Figure 6 shows the perspective views of the metal element. 7 before bending the protruding parts 9a , 9b of the metal element 7 represent. Thus, each of the Fig. 4 to Fig. 6 the metal element 7 before the assembly process is completed.

[0030] The ring-shaped base body 8 of the metal element 7 includes an opening 10 If the metal element 8 The connections run from the capacitor, which is mounted on the capacitor. 2a , 2b of the winding element through the opening 10 in the basic body 8 The opening 10is greater than the distance between the connections 2a , 2b Accordingly, the metal element 7 can be combined with a wide variety of winding elements and sealing elements, whereby the position of the connections 2a , 2b can be varied.

[0031] The metal element 7 comprises two preceding parts 9a , 9b . Both of the preceding parts 9a , 9b They protrude in the same direction, i.e., in a direction away from the winding element. Each of the protruding parts 9a , 9b is a pin. The length of the pins is chosen such that the protruding parts 9a , 9b through a mounting plate 11 questions that later refer to Fig. 3 is described. The length of the preceding parts 9a , 9b is chosen in such a way that a part of the preceding parts 9a , 9b, which is through the mounting plate 11 protrudes, can be bent over and can form a contact for surface mounting.

[0032] The sealing element 5 includes a lead 20 , which in one direction away from the winding element and towards the metal element 7 protrudes. The shape of the protrusion. 20 is attached to the shape of the opening 10 in the ring-shaped base body 8 adapted to the metal element. 7 is designed to be attached to the sealing element 5 to be attached. If the metal element 7 on the sealing element 5 The projection is attached 20 into the opening 10 inserted. The lead 20 stabilizes the mechanical connection of the metal element 7 with the sealing element 5 before mounting the mounting plate 11 and before bending the protruding parts 9a , 9bof the metal element 7 .

[0033] The Fig. 2 and Fig. Figure 3 shows a capacitor according to a first embodiment during an assembly process. Fig. Figure 4 shows the capacitor according to the first embodiment after completion of the assembly.

[0034] The capacitor is designed to be mounted on a printed circuit board (PCB) using a surface-mount process. When surface-mounted, the capacitor is mechanically and galvanically connected to the PCB.

[0035] In Fig. 2, which represents a first stage of the assembly process, are the connections. 2a , 2b Wires with a circular cross-section. The metal element 7 was applied to the sealing element 5 set up and is supported by the lead 20 on the sealing element 5 held.

[0036] Fig. Figure 3 shows the capacitor in a second stage of the assembly process. The sealing element 5 and the metal element 7 were located at the bottom of the casing 1 arranged. A groove 12 and a curl 13 were moved to the lower end of the case 1 added by adding the groove 12 and the rolling 13 is the sealing element 5 in the case 1 arranged and attached to the housing 1 attached in such a way that the housing 1 from the sealing element 5 is sealed. The groove 12 and the rolling 13 provide a mechanical fastening that prevents movement of the sealing element 5 relative to the case 1 prevents. The groove 12 and the rolling 13 Furthermore, attach the metal element. 7mechanically. No additional elements or means are required to fasten the metal element. 7 on the case 1 required. Rather, the same fasteners used to attach the sealing element make it possible. 5 be used, i.e. the groove 12 and the rolling 13 , including the fastening of the metal element 7 on the case 1 .

[0037] The connections 2a , 2b The winding element was pressed and cut in such a way that it forms contact pins.

[0038] The connections 2a , 2b The contact pins formed by the winding element are connected by a first imaginary line, which is perpendicular to a second imaginary line, which defines the protruding parts. 9a , 9b of the metal element 7 connects.

[0039] The capacitor also includes the aforementioned mounting plate.11 , which in Fig. 3 is shown. The mounting plate 11 is designed to be attached to the lower end of the capacitor.

[0040] The mounting plate 11 has a first surface 14 , which faces the housing. The mounting plate 11 has a second surface 15 , which are from the casing 1 is turned away. The second surface 15 the mounting plate 11 is a mounting surface of the capacitor that rests against the circuit board when the capacitor is surface-mounted.

[0041] The mounting plate 11 includes four openings 16 , which are designed to carry out the two preceding parts 9a , 9b of the metal element 7 and the two connections 2a , 2b to accommodate the winding element. The mounting plate 11 The mounting plate is made of a non-conductive material.11 has a thickness that is less than the length of the protruding parts 9a , 9b of the metal element 7 and less than the length of the connections 2a , 2b of the winding element.

[0042] Fig. Figure 4 shows the capacitor after completion of the assembly process. The preceding parts 9a , 9b of the metal element 7 were through the openings 16 in the mounting plate 11 guided and then the preceding parts were 9a , 9b bent over.

[0043] Each of the Fig. 8, Fig. 9 and Fig. 10 shows the metal element 7 after bending the pins.

[0044] The capacitor has four mechanical contacts on its mounting surface, which can be attached to the circuit board via surface mounting. Two of the contacts are connected to the terminals. 2a , 2bof the winding element. These contacts are designed to provide mechanical fastening and electrical contact between the winding element and the circuit board. Furthermore, two contacts are formed by the aforementioned parts. 9a , 9b of the metal element 7 formed. These two contacts are designed to provide mechanical fastening of the capacitor to the circuit board after surface mounting. The protruding parts 9a , 9b of the metal element 7 They do not provide an electrical connection to the winding element. The four contacts are arranged to form the four arms of a cross, without touching each other.

[0045] Each of the contacts also provides a thermal connection. In particular, the metal element 7 with the case 1 thermally bonded. Accordingly, the metal element bears the load. 7during surface mounting, for example by re-soldering, to accelerate heat transfer to solder pads of the printed circuit board.

[0046] Surface mounting can be performed, for example, using a reflow soldering process. The capacitor can be positioned on the printed circuit board (PCB), with each of its four contacts placed on a solder pad. The capacitor on the PCB is then moved to an oven and heated. To accelerate the heating process, it is essential to apply heat quickly to the solder pads.

[0047] Heat emanating from the casing 1 During remelting, the metal element can be removed. 7 , the one with the case 1The heat, which is thermally connected, is transferred directly to the solder pads. Thus, the solder pads are heated not only by heat applied to the circuit board, but also by heat from the housing. 1 absorbed and through the metal element 7 is transferred to the soldering surfaces. Accordingly, the metal element enables 7 an acceleration of the surface mounting of the capacitor to the circuit board.

[0048] During normal operation of the capacitor, heat can also be drawn from the casing. 1 through the metal element 7 to be transferred to the circuit board. Thus, the metal element enables 7 The use of the printed circuit board as a heat sink. Ripple currents applied to the capacitor during normal operation can generate heat, and this heat is generally transferred from the winding element to the casing. 1 transferred. Since the housing 1with the circuit board through the metal element 7 Since it is thermally connected, the circuit board can be used as a heat sink.

[0049] As explained above, the metal element 7 mechanically on the housing 1 It is attached. No adhesives or external plastic parts are used to attach the metal element. 7 required. Unlike adhesives or external plastic parts, which are sensitive to temperature changes and humidity and generally suffer from aging, a purely mechanical fastening of the metal element suffers from this. 7 not subject to aging due to temperature changes or humidity. The mechanical fastening of the metal element. 7 It is stable within a wide temperature range and within a wide humidity range.

[0050] The Fig. 11 and Fig. Figure 12 shows a capacitor according to a second embodiment during various stages of the assembly process.

[0051] The Fig. 13 and Fig. Figure 14 shows the capacitor after completion of the assembly process.

[0052] The second embodiment differs from the first embodiment in the design of the metal element. 7 According to the second embodiment, the metal element 7 formed from a stamped metal sheet, which also has a ring-shaped base body 8 has. Furthermore, the preceding parts 9a , 9b of the metal element 7 not formed by pins, but by a metal strip which in its middle part 17 protrudes towards the mounting surface. A first end 18 and a second ending 19 The strips are connected to the ring-shaped base body. The first end 18 and the second end 19of the strip are divided by the middle part 17 connected. The middle part 17 the foregoing elements 9a , 9b It is U-shaped.

[0053] Fig. Figure 11 shows the capacitor of the second embodiment in a first stage of the assembly process, similar to Fig. 2. The metal element 7 is under the sealing element 5 of the case 1 arranged.

[0054] Fig. Figure 12 shows the capacitor in a second stage of the assembly process, similar to Fig. 3. In the second embodiment, the mounting plate 11 to the shape of the metal element 7 adapted to the second embodiment. The openings 16 in the mounting plate 11 are attached to the preceding parts 9a , 9b adapted. Accordingly, the openings in the mounting plate of the second embodiment are formed in a circular segment.

[0055] In Fig. Figure 14 shows that, according to the second embodiment, there are also four mechanical contacts that can be attached to a printed circuit board by means of surface mounting. Two of the contacts are connected to the terminals. 2a , 2b of the winding element and two additional contacts are formed by the preceding parts 9a , 9b of the metal element 7 formed which are preferably not galvanically connected to the winding element, but are designed for an improved mechanical and thermal connection between the housing 1 and the circuit board. Reference symbol list 1 case 2a Connection of the winding element 2b Connection of the winding element 3 first end / bottom end of the case 4. Second end / upper end of the case 5 Sealing element 6 holes of the sealing element 7 Metal element 8 Basic body of the metal element 9a protruding part of the metal element 9b protruding part of the metal element 10 Opening the metal element 11 Mounting plate 12 groove 13 Rolling in 14 First surface of the mounting plate 15 second surface of the mounting plate 16 Opening the mounting plate 17 middle part 18 first end 19 second end 20 lead

Claims

[1] Capacitor, comprehensive a winding element arranged in a housing (1), a mounting plate (11) comprising a non-conductive material and attached to the housing (1), and a metal element (7) arranged between the housing (1) and the mounting plate (11), wherein the metal element (7) comprises a projecting part (9a, 9b) extending through the mounting plate (11). [2] Capacitor according to claim 1, wherein the protruding part (9a, 9b) of the metal element (7) is configured to be attached to a printed circuit board when the capacitor is surface-mounted to the printed circuit board. [3] Capacitor according to the preceding claim, wherein the metal element (7) is configured to transfer heat from the housing (1) to the circuit board. [4] Capacitor according to one of claims 2 or 3, wherein the winding element comprises two terminals (2a, 2b) forming two contacts of the capacitor which are arranged to be attached to the printed circuit board during surface mounting, and wherein the metal element (7) provides two additional mechanical contacts which are arranged to be attached during surface mounting. [5] Capacitor according to one of the preceding claims, wherein the metal element (7) is thermally connected to the housing (1). [6] Capacitor according to one of the preceding claims, wherein the mounting plate (11) comprises an opening (16), wherein the protruding part (9a, 9b) of the metal element (7) extends through the opening (16). [7] Capacitor according to one of the preceding claims, wherein the metal element (7) is clamped between the mounting plate (11) and the housing (1). [8] Capacitor according to one of the preceding claims, wherein the metal element (7) is merely mechanically attached to the housing (1). [9] Capacitor according to one of the preceding claims, wherein the metal element (7) is attached to the housing (1) by means of a bead (12) and a crimped edge (13). [10] Capacitor according to one of the preceding claims, wherein the metal element (7) comprises an annular base body (8). [11] Capacitor according to any of the preceding claims, wherein the protruding part (9a, 9b) of the metal element (7) is a pin. [12] Capacitor according to the preceding claim, the pin is bent in such a way that it forms a surface parallel to a mounting surface of the capacitor. [13] Capacitor according to any one of claims 1 to 10, wherein the metal element (7) is a stamped metal sheet and the protruding part (9a, 9b) is formed by stamping technology. [14] Capacitor according to one of the preceding claims, wherein the metal element (7) is not galvanically connected to the winding element. [15] Capacitor according to one of the preceding claims, wherein the capacitor comprises a sealing element (5) which seals the housing (1). [16] Capacitor according to the preceding claim, wherein the metal element (7) is arranged between the sealing element (5) and the mounting plate (11). [17] Arrangement comprising a printed circuit board and a capacitor according to one of the preceding claims, wherein the capacitor is attached to the printed circuit board by means of surface mounting.