Capacitors

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 fixed 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 protruding portion (9a, 9b) protruding through the mounting plate (11).

Description

Technical Field

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

[0002] Standard SMD capacitors typically have poor mechanical fixation to the PCB via their ribbon wires. In addition, heat dissipation from the SMD capacitor to the PCB is limited by the physical size of the wires.

[0003] Therefore, there is a need for an improved capacitor designed for surface mounting which overcomes at least one of the disadvantages discussed above. It is an object of the present invention to provide such a capacitor.

[0004] This object is achieved by the subject matter of claim 1 . Summary of the invention

[0005] A capacitor is provided, comprising: a winding element arranged in a housing; a mounting plate comprising a non-conductive material and fixed to the housing; and a metal element arranged between the housing and the mounting plate, wherein the metal element comprises a protruding portion protruding through the mounting plate. In addition, the capacitor can include a sealing element.

[0006] By adding a metal element between the housing and the mounting plate of the capacitor, the above-discussed disadvantages of the SMD capacitor can be overcome. The metal element can be in thermal contact with the housing. Therefore, during surface mounting (e.g., by reflow soldering), the heat collected by the housing can be transferred to the PCB via the metal element. Therefore, during reflow soldering, heat can be applied to the pads of the PCB very quickly, thereby accelerating the soldering process, because not only can heat be applied via the PCB itself, but also the heat collected by the housing can be applied to the pads. In addition, during normal operation of the capacitor, the metal element can remain thermally connected to the housing, so that the heat generated by the winding elements inside the housing can be transferred to the printed circuit board by the metal element. Therefore, the addition of the metal element can allow the printed circuit board to be used as a heat sink. For example, ripple current can generate heat in the winding elements. The metal element can contribute to the thermal management of the capacitor by transferring heat away from the housing.

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

[0008] The mounting plate can be a small plate having lateral dimensions similar to those of the housing. The housing can be fixed to the mounting plate. The mounting plate can be designed to be fixed to a printed circuit board during surface mounting.

[0009] The protruding portion of the metal element may extend beyond the mounting plate in a direction away from the winding element.

[0010] The protruding portion of the metal element can be configured to be fixed to the printed circuit board when the capacitor is surface mounted to the PCB. In particular, the protruding portion of the metal element can form a mechanical contact that can be fixed to a pad of the PCB by soldering.

[0011] The metal element can be configured to transfer heat from the housing to the PCB. Therefore, during surface mounting, the metal element can speed up the soldering process because the heat connected by the housing is effectively transferred to the pads. In addition, during normal operation of the capacitor, the metal element can enable heat to be transferred from the housing to the PCB, allowing the PCB to act as a heat sink.

[0012] The winding element can include two terminals, which form two contacts configured to be fixed to the PCB during surface mounting. The two terminals of the winding element can provide electrical contact of the winding element to the PCB. In addition, the two terminals of the winding element can also be thermally connected to the PCB and mechanically connected to the PCB.

[0013] The metal element can provide two additional mechanical contacts, which are configured to be fixed during surface mounting. The additional mechanical contacts can be formed by the protruding portion of the metal element. The contacts provided by the metal element are preferably not electrically connected to the winding element. The contacts provided by the metal element can be mechanically connected and thermally connected to the PCB. Therefore, the metal element can contribute to a better mechanical and thermal connection of the PCB and the capacitor.

[0014] The terminals of the winding elements can protrude through the recesses in the mounting plate.

[0015] The metal element can be clamped between the mounting plate and the housing. The metal element can be fixed to the housing completely mechanically. In particular, no glue and external plastic parts are required to fix the metal element to the housing. Instead, the metal element can be fixed to the housing by the same mechanical means, which also fixes the sealing element of the closed housing to the rest of the housing. In particular, the metal element can be fixed to the housing by bending and crimping. In short, bending and crimping are required for closing the housing with the sealing element so that no additional means are required to fix the metal element. The metal element can be arranged between the sealing element and the mounting plate. In particular, the metal element can abut the sealing element arranged at the lower end of the housing. The metal element also abuts the mounting plate.

[0016] The metal element can include an annular base body. The annular shape of the base body can define an opening, wherein the terminal of the winding element can pass through the opening. 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, wherein the position and size of the terminal are not limited by the opening in the metal element.

[0017] The protruding portion of the metal element can be a pin. The pin can be bent before or after passing through the opening in the mounting plate. In addition, by bending the pin, the metal element can be fixed to the mounting plate so that the metal element is prevented from moving relative to the mounting plate in the axial direction.

[0018] The pin can be bent so that it forms a surface parallel to the mounting surface of the capacitor. The mounting surface of the capacitor can be the lower surface of the mounting plate facing away from the winding element. The mounting surface of the capacitor can be designed to abut against the PCB when the capacitor is surface mounted to the PCB.

[0019] The metal element can be a stamped metal sheet, wherein the protruding portion is formed by stamping.

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

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

[0022] The invention further relates to an arrangement comprising a PCB and a capacitor as described above, wherein the capacitor is fixed to the PCB by surface mounting. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] The following preferred embodiments of the present invention are described with respect to the accompanying drawings.

[0024] Figure 1 The housing, the sealing element and the metal element of the capacitor are shown in an exploded view.

[0025] Figure 2 and Figure 3 showing perspective views of a capacitor according to a first embodiment during different stages of the assembly process;

[0026] Figure 4 shows the capacitor according to the first embodiment after the assembly process is completed;

[0027] Figure 5 , Figure 6 as well as Figure 7 shows the metal element according to the first embodiment before bending the protruding portion;

[0028] Figure 8 , Fig. 9 as well as Fig.10 shows the metal element according to the first embodiment after bending the protruding portion;

[0029] Fig.11 and Fig.12 shows a capacitor according to a second embodiment during different stages of an assembly process; and

[0030] Fig.13 and Fig.14 The capacitor of the second embodiment is shown after the assembly process is completed. DETAILED DESCRIPTION

[0031] Figure 1 The housing 1 , the sealing element 5 and the metal element 7 of the capacitor are shown in an exploded view.

[0032] The capacitor includes a winding element arranged inside a housing 1. The housing 1 is an aluminum can. The housing 1 is cylindrical. The winding element includes two terminals 2a, 2b protruding outward from the housing 1. The terminals 2a, 2b of the winding element are electrical terminals configured to be connected to a printed circuit board during surface mounting.

[0033] The housing 1 has a first end 3 and a second end 4. The first end 3 of the housing 1 is open. Wires forming the terminals 2a, 2b of the winding element protrude outward from the first end 3 of the housing 1. The second end 4 of the housing 1 is arranged opposite to the first end 3. The second end 4 is closed. In this document, the first end 3 is also referred to as the lower end, and the second end 4 is also referred to as the upper end.

[0034] The capacitor further comprises a sealing element 5 configured to seal the housing 1. In particular, the sealing element 5 is configured to seal the lower end 3 of the housing 1. The sealing element 5 comprises a non-conductive material, such as rubber. Rubber is particularly suitable as a material for the sealing element 5 because rubber has high elasticity and can therefore reliably close the housing 1. The sealing element 5 comprises two holes 6 configured to receive the terminals 2a, 2b of the winding element. The sealing element 5 is inserted into the housing 1 from the lower end 3 of the housing 1.

[0035] The capacitor comprises a metal element 7 which is arranged below the sealing element 5 in a direction facing away from the winding element. The metal element 7 has an annular base body 8 and comprises two protruding parts 9a, 9b.

[0036] exist Figure 4 , Figure 5 as well as Figure 6 Further details of the metal element 7 are shown in each of the Figure 4 , Figure 5 as well as Figure 6 A perspective view of the metal element 7 is shown before the protruding portions 9a, 9b of the metal element 7 are bent. Figures 4 to 6 Each of the figures shows a metal element 7 before the assembly process is completed.

[0037] The annular base body 8 of the metal element 7 comprises an opening 10. When the metal element 8 is assembled to the capacitor, the terminals 2a, 2b of the winding element pass through the opening 10 in the base body 8. The opening 10 is larger than the distance between the terminals 2a, 2b. Therefore, the metal element 7 can be combined with a wide variety of winding elements and sealing elements, wherein the positions of the terminals 2a, 2b can vary.

[0038] The metal element 7 comprises two protruding parts 9a, 9b. Both protruding parts 9a, 9b protrude in the same direction (i.e. in the direction away from the winding element). Each of the protruding parts 9a, 9b is a pin. The length of the pin is selected so that the protruding parts 9a, 9b protrude through the mounting plate 11, which will be described later with respect to the mounting plate 11. Figure 3 The mounting plate 11 is described below. The lengths of the protruding portions 9a, 9b are selected so that the portions of the protruding portions 9a, 9b that protrude through the mounting plate 11 can be bent and can form contacts for surface mounting.

[0039] The sealing element 5 comprises a protrusion 20 protruding in a direction away from the winding element and towards the metal element 7. The shape of the protrusion 20 is adapted to the shape of the opening 10 in the annular base body 8 of the metal element. The metal element 7 is configured to be attached to the sealing element 5. When the metal element 7 is attached to the sealing element 5, the protrusion 20 is inserted into the opening 10. The protrusion 20 stabilizes the mechanical connection of the metal element 7 to the sealing element 5 before assembling the mounting plate 11 and before bending the protruding parts 9a, 9b of the metal element 7.

[0040] Figure 2 and Figure 3 The capacitor according to the first embodiment is shown during the assembly process. Figure 4 The capacitor according to the first embodiment is shown after assembly is complete.

[0041] The capacitor is designed to be fixed to a printed circuit board (PCB) in a surface mounting process. When surface mounted to a PCB, the capacitor is mechanically and electrically connected to the PCB.

[0042] In the first stage of the assembly process shown Figure 2 In FIG. 5 , the terminals 2 a, 2 b are wires having a circular cross section. The metal element 7 has been placed onto the sealing element 5 and is held thereon by the protrusion 20 .

[0043] Figure 3 The capacitor in the second stage of the assembly process is shown. The sealing element 5 and the metal element 7 have been arranged at the lower end of the housing 1. A crimp 12 and a curling 13 have been added to the lower end of the housing 1. By adding the crimp 12 and the curling 13, the sealing element 5 is positioned in the housing 1 and fixed to the housing 1 so that the housing 1 is sealed by the sealing element 5. The crimp 12 and the curling 13 provide a mechanical fixation that prevents the movement of the sealing element 5 relative to the housing 1. The crimp 12 and the curling 13 also mechanically fix the metal element 7. No additional elements or means are required to fix the metal element 7 to the housing 1. On the contrary, the same fixing means for fixing the sealing element 5 (i.e., the crimp 12 and the curling 13) also enable the metal element 7 to be fixed to the housing 1.

[0044] The terminals 2a, 2b of the winding element have been pressed and cut so that they form contact pins. The contact pins formed by the terminals 2a, 2b of the winding element are connected by a first imaginary line which is perpendicular to a second imaginary line connecting the protruding parts 9a, 9b of the metal element 7.

[0045] The capacitor is further included in Figure 3 The above-mentioned mounting plate 11 is shown in FIG. The mounting plate 11 is configured to be fixed to the lower end portion of the capacitor.

[0046] The mounting board 11 has a first surface 14 facing toward the housing. The mounting board 11 has a second surface 15 facing away from the housing 1. The second surface 15 of the mounting board 11 is the mounting surface of the capacitor abutting against the PCB in the case where the capacitor is surface mounted.

[0047] The mounting plate 11 comprises four openings 16 configured to receive the two protruding portions 9a, 9b of the metal element 7 and the two terminals 2a, 2b of the winding element. The mounting plate 11 comprises a non-conductive material. The mounting plate 11 has a thickness smaller than the length of the protruding portions 9a, 9b of the metal element 7 and smaller than the length of the terminals 2a, 2b of the winding element.

[0048] Figure 4 The capacitor is shown after the assembly process is completed. The protruding portions 9a, 9b of the metal element 7 have passed through the openings 16 in the mounting plate 11 and subsequently, the protruding portions 9a, 9b have been bent.

[0049] Figure 8 , Fig. 9 as well as Fig.10 Each of the figures shows the metal element 7 after bending the pins.

[0050] The capacitor includes four mechanical contacts located at its mounting surface, which can be fixed to the printed circuit board by surface mounting. Two of the contacts are formed by the terminals 2a, 2b of the winding element. These contacts are configured to provide mechanical fixation and electrical contact of the winding element to the printed circuit board. Further, two contacts are formed by the protruding parts 9a, 9b of the metal element 7. These two contacts are configured to provide mechanical fixation of the capacitor to the printed circuit board after surface mounting. The protruding parts 9a, 9b of the metal element 7 do not provide electrical connection to the winding element. The four contacts are arranged so that they form four cross arms, and the contacts do not touch each other.

[0051] Each of the contacts also provides a thermal connection. In particular, the metal element 7 is thermally connected to the housing 1. Thus, during surface mounting, such as by reflow soldering, the metal element 7 helps to accelerate the heat transfer to the pads of the printed circuit board.

[0052] For example, surface mounting can be performed in a reflow soldering process. The capacitor can be arranged on a printed circuit board, wherein each of the four contacts is arranged on a pad. The capacitor on the PCB is moved into an oven and heated. In order to speed up the heating process, it is critical to quickly apply heat to the pad.

[0053] During reflow soldering, the heat collected by the housing 1 can be directly transferred to the pads through the metal element 7 thermally connected to the housing 1. Therefore, the pads are heated not only by the heat applied to the printed circuit board, but also by the heat collected from the housing 1 and transferred to the pads via the metal element 7. Therefore, the metal element 7 enables accelerated surface mounting of the capacitor to the PCB.

[0054] During normal operation of the capacitor, heat can also be transferred from the housing 1 to the printed circuit board via the metal element 7. Thus, the metal element 7 allows the PCB to be used as a heat sink. The ripple current applied to the capacitor during normal operation can generate heat, and this heat is generally transferred from the winding elements to the housing 1. Because the housing 1 is thermally connected to the PCB via the metal element 7, the PCB can be used as a heat sink.

[0055] As discussed above, the metal element 7 is mechanically fixed to the housing 1. No glue or external plastic parts are required for fixing the metal element 7. In contrast to glue and external plastic parts, which are sensitive to temperature changes and humidity and generally subject to aging, the completely mechanical fixing of the metal element 7 does not suffer from aging due to temperature changes or humidity. The mechanical fixing of the metal element 7 is stable within a wide temperature range and within a wide humidity range.

[0056] Fig.11 and Fig.12 A capacitor according to a second embodiment is shown during different stages of the assembly process.

[0057] Fig.13 and Fig.14 The capacitor is shown after finalization of the assembly process.

[0058] 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 is formed by a stamped metal sheet also having an annular base body 8. Further, the protruding parts 9a, 9b of the metal element 7 are not formed by pins but by a metal strip protruding towards the mounting surface in the middle part 17 of the metal element 7. The first end 18 and the second end 19 of the strip are connected to the annular base body. The first end 18 and the second end 19 of the strip are connected by the middle part 17. The middle part 17 of the protruding elements 9a, 9b is u-shaped.

[0059] Fig.11 Shown with Figure 2 Similarly the capacitor of the second embodiment is in the first stage of the assembly process. The metal element 7 is arranged below the sealing element 5 of the housing 1 .

[0060] Fig.12 Shown with Figure 3A capacitor in a second stage of a similar assembly process. In the second embodiment, the mounting plate 11 is adapted to the shape of the metal element 7 of the second embodiment. The opening 16 in the mounting plate 11 is adapted to the protruding portions 9a, 9b. Thus, the opening in the mounting plate of the second embodiment is formed in a segmented circle.

[0061] Can Fig.14 As can be seen in FIG. 1 , according to the second embodiment, there are also four mechanical contacts that can be fixed to a printed surface board by surface mounting. Two of the contacts are formed by the terminals 2a, 2b of the winding element, while the two additional contacts are formed by the protruding parts 9a, 9b of the metal element 7, which are preferably not electrically connected to the winding element, but provide an improved mechanical and thermal connection between the housing 1 and the printed circuit board.

[0062] Reference numerals

[0063] 1 Housing

[0064] 2a Terminals of winding components

[0065] 2b Terminals of winding components

[0066] 3 First end / lower end of the housing

[0067] 4 Second end / upper end of the housing

[0068] 5 Sealing element

[0069] 6 Hole for sealing element

[0070] 7 Metal components

[0071] 8 Base body of metal component

[0072] 9a Protruding parts of metal components

[0073] 9b Protruding parts of metal components

[0074] 10 Openings for metal components

[0075] 11 Mounting plate

[0076] 12 Bend

[0077] 13. Curling

[0078] 14 First surface of mounting plate

[0079] 15 Second surface of mounting plate

[0080] 16 Opening for mounting plate

[0081] 17 Middle part

[0082] 18 First end

[0083] 19 Second end

[0084] 20 protrusion.

Claims

1. A capacitor, comprising: A winding element arranged in an aluminum can (1); a mounting plate (11) comprising a non-conductive material and being fixed to the aluminum can (1); a metal element (7) comprising an annular base body arranged between the aluminum can (1) and the mounting plate (11), wherein the metal element (7) comprises a protruding portion (9a, 9b) protruding through the mounting plate (11), wherein the protruding portion is a pin, and wherein the pin is bent so that the pin forms a surface parallel to the mounting surface of the capacitor; wherein the mounting plate is a small plate having a lateral dimension corresponding to the lateral dimension of the aluminum can; wherein the protruding portions (9a, 9b) of the metal element (7) are configured to be fixed to a printed circuit board when the capacitor is surface mounted on the printed circuit board; wherein the metal element (7) is in thermal contact with the aluminum can (1); wherein the metal element (7) is configured to transfer heat collected by the aluminum can (1) to the pads of the printed circuit board during reflow soldering, thereby accelerating the reflow soldering process because heat is applied not only via the PCB itself, but also the heat collected by the aluminum can is applied to the pads; wherein the mounting plate (11) comprises an opening (16) configured to receive a protruding portion (9a, 9b) of a metal element (7), wherein the protruding portion (9a, 9b) of the metal element (7) passes through the opening (16) in the mounting plate during assembly; wherein the capacitor comprises a sealing element (5) for sealing the aluminum can (1); Wherein, the metal element (7) is arranged between the sealing element (5) and the mounting plate (11); The sealing element (5) comprises a protrusion (20) protruding in a direction away from the winding element and toward the metal element (7); wherein the shape of the protrusion (20) is adapted to the shape of the opening (10) in the annular base body (8) of the metal element; and The projection (20) is inserted into an opening (10) in the annular base body (8).

2. The capacitor according to claim 1, It is characterized in that The winding element comprises two terminals (2a, 2b) forming two contacts of the capacitor configured to be fixed to the printed circuit board during surface mounting, and The metal element (7) provides two additional mechanical contacts, which are configured to be fixed during surface mounting.

3. The capacitor according to claim 1 or 2, It is characterized in that The metal element (7) is clamped between the mounting plate (11) and the aluminum can (1).

4. The capacitor according to claim 3, It is characterized in that The metal element (7) is completely mechanically fixed to the aluminum can (1).

5. The capacitor according to claim 4, It is characterized in that The metal element (7) is fixed to the aluminum can (1) by bending (12) and hemming (13).

6. The capacitor according to any one of claims 1, 2, 4 and 5, It is characterized in that The metal element (7) is a stamped metal sheet and the protruding portions (9a, 9b) are formed by stamping.

7. The capacitor according to any one of claims 1, 2, 4 and 5, It is characterized in that The metal element (7) is not electrically connected to the winding element.

8. A capacitor assembly comprising a printed circuit board and a capacitor according to any one of claims 1 to 7, characterized in that: The capacitor is fixed to the printed circuit board by surface mounting.

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