Printed circuit board arrangement, transmission control unit with a printed circuit board arrangement and use of the printed circuit board arrangement in a transmission control unit

Abstract

Printed circuit board arrangement (10) for a transmission control unit of a motor vehicle, comprising a first printed circuit board (12) having a first top surface (24) and a second top surface (26) spaced apart from the first top surface (24), and the first top surface (24) and the second top surface (26) being equipped with at least one electronic component (32), a second printed circuit board (14) spaced apart from the first printed circuit board (12), the second printed circuit board (14) having a first top surface (28) and a second top surface (30) spaced apart from the first top surface (28), wherein the first top surface (28) of the second printed circuit board (14) faces the first printed circuit board (12) and is equipped with at least one electronic component (32), and a plurality of vias (18) electrically connecting the first printed circuit board (12) and the second printed circuit board (14) to each other.wherein the vias (18) are arranged and / or formed at least partially in an annular carrier element (16), wherein the carrier element (16) is arranged between the two printed circuit boards (12, 14) and the printed circuit boards (12, 14) abut the carrier element (16) in sections, a cavity and / or space (44) is formed over the printed circuit boards (12, 14) and the carrier element (16), and at least one of the electronic components (32) arranged on the first printed circuit board (12) and / or the second printed circuit board (14) projects into the cavity and / or space (44), wherein projections in the axial direction of the carrier element (16) are formed at least partially on an end face of the carrier element (16), and the respective printed circuit board (12, 14) abuts the projections, and a gap exists between the respective printed circuit board (12, 14) and the The front face of the support element (16) is formed.

Description

The invention relates to a printed circuit board arrangement for a transmission control unit of a motor vehicle, in which at least two printed circuit boards arranged parallel to each other at a distance from one another are electrically connected to each other via vias, the upper surfaces of the printed circuit boards can be fitted with electronic components, and the vias are arranged in an annular carrier element that acts as a spacer between the two printed circuit boards. The invention also relates to a transmission control unit with the printed circuit board arrangement according to the invention and to the use of the printed circuit board arrangement according to the invention in a transmission control unit of a motor vehicle. A printed circuit board arrangement for a transmission control unit is known, for example, from DE 10 2013 215 246 A1. In this known printed circuit board arrangement, two parallel printed circuit boards are electrically connected to each other via press-fit connections. An annular spacer is arranged between the printed circuit boards to maintain distance between them and to create a cavity between the two boards. This cavity serves to house electronic components located on one side of the two printed circuit boards, thus protecting them from external influences. The edge region of the two printed circuit boards is encapsulated with a plastic to create a media-tight seal. The cavity is at least partially filled with a thermally conductive gel. US Patent 2012 0 003 847 A1 describes a connector for connecting printed circuit boards (PCBs), in which two PCBs are spaced apart by an annular connector. Contact elements are arranged within the connector to electrically connect the two PCBs. A screw element is guided through a cavity in the annular connector to force-fit the PCBs together. US 2014 0 126 159 A1 describes an electronic device in which two printed circuit boards populated with electrical components are connected to each other via metallic rods, and the printed circuit boards and, in particular, the electrical components arranged on the printed circuit boards are encapsulated with a mold. US Patent 2010 0 284 159 A1 shows several circuit boards arranged at a distance from each other, with a cooling plate attached to one of the circuit boards. It is an object of the invention to provide a reliable and robust printed circuit board arrangement for a transmission control unit with an increased integration density of electrical controls and / or circuits, which can be easily potted with a potting material. This object is achieved by the subject matter of claim 1. Preferred embodiments of the invention are specified in the dependent claims, the following description, and the figures, each feature being able to represent an aspect of the invention both individually and in combination. According to the invention, a printed circuit board arrangement for a transmission control unit of a motor vehicle is provided, comprising a first printed circuit board having a first top surface and a second top surface spaced apart from the first top surface, and the first top surface and the second top surface being equipped with at least one electronic component, a second printed circuit board spaced apart from the first printed circuit board, having a first top surface and a second top surface spaced apart from the first top surface, wherein the first top surface of the second printed circuit board faces the first printed circuit board and is equipped with at least one electronic component, and a plurality of vias that electrically connect the first printed circuit board and the second printed circuit board to each other, wherein the vias are arranged and / or formed at least partially in an annular carrier element.wherein the support element is arranged between the two printed circuit boards and the printed circuit boards abut the support element section by section, and a cavity and / or gap is formed over the printed circuit boards and the support element, and at least one of the electronic components arranged on the first printed circuit board and / or the second printed circuit board projects into the cavity and / or gap, wherein at least section by section projections in the axial direction of the support element are formed on an end face of the support element, and the respective printed circuit board abuts the projections, and a gap is formed between the respective printed circuit board and the end face of the support element. It is therefore an aspect of the invention that a printed circuit board arrangement for a transmission control unit of a motor vehicle is provided. The motor vehicle can preferably be at least partially electrically powered. The printed circuit board arrangement comprises a first printed circuit board and a second printed circuit board that differs from the first. Both the first and second printed circuit boards are preferably designed as multilayer printed circuit boards. The dimensions of the first printed circuit board can differ from those of the second. In other words, for example, the length and / or width of the first printed circuit board can be smaller than the length and / or width of the second printed circuit board. Furthermore, the geometric contours of the two printed circuit boards can be the same or different. Both the first and second printed circuit boards (PCBs) each have a first top surface and a second top surface. The respective top surfaces of the PCBs are preferably arranged parallel to each other and spaced apart. At least one electronic component is arranged on each of the first and second top surfaces of the first PCB. The second PCB has at least one electronic component on its first top surface, which faces the first PCB. The integration density of the electronic components to be implemented can be increased by having two PCBs arranged side by side, with electronic components arranged on a total of three top surfaces. An electronic component is preferably understood to be an electronic circuit and / or an electronic control system. Preferably, but not limited to, the electronic component is a metal-oxide-semiconductor field-effect transistor (MOSFET), an application-specific integrated circuit (ASIC), and / or an isolated bipolar transistor with an isolated gate (IGBT module). The two printed circuit boards are electrically connected to each other via a plurality of vias. A plurality of vias means 2, 3, 4, 5, 6, 7, 8, 9, 10 or even more than 10 vias. Vias are preferably press-fit connections, also known as through-hole technology (THT). The vias are arranged, at least partially, in an annular carrier element, which is preferably made of a non-conductive or insulating material, in particular a plastic.The term "at least section-by-section arrangement of the vias in the carrier element" means that at least one first end section for electrical connection with the first printed circuit board and a second end section extending from the first end section in an axial direction of the via element for electrical connection with the second printed circuit board are designed without a carrier element. In other words, the carrier element is arranged and / or formed between the first end section and the second end section of the via element. The support element is positioned between the two circuit boards and rests against them in sections. A predefined distance between the two circuit boards can be maintained via the support element. Because the vias are arranged within the carrier element, a multiple of these vias can be placed on either the first or second printed circuit board (PCB) in a single assembly operation, thus accelerating the manufacturing and / or assembly process. Furthermore, arranging the vias within the carrier element increases their rigidity, allowing for more material-efficient designs, at least in certain sections. This, in turn, reduces the manufacturing costs of the PCB assembly.Furthermore, the circular shape of the support element and the connection of the via elements arranged in the support element to the printed circuit boards can provide a printed circuit board arrangement that can exhibit increased vibration resistance. The vias are arranged within the annular carrier element, which does not necessarily require an annular arrangement of the vias themselves, which are spaced apart from one another. An advantageous embodiment of the invention is that the vias are arranged at intervals on an imaginary annulus. This means that all vias are equidistant from the center point of the imaginary annulus. Preferably, the center point of the imaginary annulus is the same as the center point of the annular carrier element. Such an arrangement of the vias on an imaginary annulus can increase the vibration resistance of the printed circuit board assembly. According to the invention, at least partial projections are formed in the axial direction of the support element on an end face of the support element, wherein the respective printed circuit board rests against the projections, and a gap is formed between the respective printed circuit board and the end face of the support element. In this way, the gap can be easily, at least partially, filled with the potting material. In principle, it is conceivable that the spacing between the vias arranged on the hypothetical circular ring may vary. In a preferred embodiment of the invention, the vias are arranged at regular and / or uniform intervals. This further symmetrical arrangement of the vias can additionally contribute to the vibration resistance of the printed circuit board assembly. An advantageous embodiment of the invention lies in the fact that the first printed circuit board and / or the second printed circuit board is at least partially overmolded and / or potted with a plastic material, so that the electronic components arranged on the printed circuit board are protected from external media. This overmolding process can also be referred to as overmolding. Overmolding protects the electronic components from aggressive media, such as preferably oil, in particular gear oil. By overmolding the printed circuit board and / or printed circuit board assembly, a housing for enclosing the printed circuit board assembly can be dispensed with, thereby reducing the dimensions and also the cost of the printed circuit board assembly. In a preferred embodiment of the invention, the cavity and / or space is at least partially encapsulated with a potting material, preferably a plastic material. By encapsulating the space and / or cavity, the electronic components projecting therein can be at least partially encased, thus achieving increased media tightness of the printed circuit board assembly. Heat transfer can also occur via the encapsulation to dissipate heat generated by the electronic components to the outside. Preferably, the printed circuit boards only partially contact the support element, so that a gap is formed between the printed circuit board and the support element in certain areas, through which the potting material can enter the cavity and / or space. Preferably, the projections are formed between the respective vias. A further advantage is that the potting material for the gap is identical to the potting material used for the partial overmolding of the first and second printed circuit boards. This allows for the creation of a media-tight printed circuit board assembly in a single overmolding and / or potting process. Since only one potting process is required, the manufacturing costs of the printed circuit board assembly can be reduced. Compared to multiple potting processes, drying times are reduced with a single potting process, thus accelerating the manufacturing process of the printed circuit board assembly. In a preferred embodiment of the invention, the first and second printed circuit boards each have through openings into which the vias for electrical connection of the two boards engage at least partially, and the potting compound is arranged at least partially in the openings of the first and / or the openings of the second printed circuit board. In this way, a metallurgical bond between the via and the opening can be established via the potting compound entering the respective opening. This increases the vibration resistance of the printed circuit board assembly. The arrangement of the potting compound in the openings is preferably facilitated by the formation of projections on the end face of the carrier element. This is particularly advantageous when the projections are located between the vias on the end face of the carrier element. In such a configuration, the respective end section of the via extends through the gap and is thus surrounded by the potting compound during the potting and / or overmold process, allowing the potting compound to flow, at least partially, into the openings where the end sections engage for electrical contact. In principle, it is conceivable that electronic components are arranged on the second side of the second circuit board in order to increase the integration density of the electronic components arranged on the circuit boards. Alternatively, an advantageous embodiment of the invention consists in the second top side of the second printed circuit board being arranged on a base body and / or a cooling plate. Preferably, the second side of the second printed circuit board is bonded to the base body by a material bond. This material bond can preferably be achieved using a thermally conductive adhesive. The base body and / or the cooling plate are preferably made of a metal, in particular aluminum. In this way, heat generated in the electronic components can preferably be transferred and / or dissipated via the potting material, the support frame, and the second printed circuit board into the base body and / or the cooling plate. This increases the reliability of the printed circuit board assembly, especially at higher temperatures. The invention also relates to a transmission control unit with the circuit board arrangement according to the invention and to the use of the circuit board arrangement according to the invention in a transmission control unit. Further features and advantages of the present invention will become apparent from the dependent claims and the exemplary embodiment below. The exemplary embodiment is not intended to be limiting, but rather to be understood as illustrative. It is meant to enable a person skilled in the art to carry out the invention. The applicant reserves the right to make one or more of the features disclosed in the exemplary embodiment the subject of patent claims or to include such features in existing claims. The exemplary embodiment is explained in more detail with reference to the drawings. These show: Fig. 1 a three-dimensional view of a printed circuit board arrangement according to a preferred embodiment of the invention, Fig. 2 a cross-section through the printed circuit board arrangement according to the preferred embodiment of the invention, Fig. 3 a cross-section through the printed circuit board arrangement with a potting, according to the preferred embodiment of the invention. Figure 1 shows a three-dimensional view of a printed circuit board arrangement 10 according to an embodiment of the invention. The printed circuit board arrangement 10 can preferably be arranged in a transmission control unit of a motor vehicle, wherein the motor vehicle can be at least partially electrically powered. The printed circuit board assembly 10 comprises a first printed circuit board 12 and a second printed circuit board 14 that is distinct from the first printed circuit board 12. The first printed circuit board 12 can be referred to as the upper printed circuit board and the second printed circuit board 14 can be referred to as the lower printed circuit board 14. In this embodiment, the first printed circuit board 12 and the second printed circuit board 14 are each designed as a multilayer printed circuit board. The dimensions of the first circuit board 12 can differ from the dimensions of the second circuit board 14. Furthermore, the geometric contours of the two circuit boards 12 and 14 can differ from one another. In the exemplary embodiment, but not limited to this one, the first circuit board 12 has a hexagonal outer contour. The second circuit board 14 has a quadrilateral outer contour. The two circuit boards 12 and 14 are arranged essentially parallel to each other. This means that one plane of the first circuit board 12 is parallel to and spaced apart from a plane of the second circuit board 14. A support element 16 is arranged between the first circuit board 12 and the second circuit board 14, which spaces the first circuit board 12 away from the second circuit board 14. In other words, the first circuit board 12 and the second circuit board 14 are partially in contact with the support element 16. The carrier element 16 is annular in shape and comprises an electrically insulating material. The electrically insulating material of the carrier element 16 is a plastic material. A plurality of vias 18 are spaced apart from one another within the carrier element 16. In this case, more than ten vias 18 are arranged within the carrier element 16, forming a press-fit connection. The vias 18 are only partially integrated into the carrier element 16.The arrangement of the vias 18, at least in sections, within the carrier element 16 means that at least one first end section 20 is formed for electrical connection with the first printed circuit board 12, and a second end section 22, extending from the first end section 20 in an axial direction of the via 18, is formed for electrical connection with the second printed circuit board 14 and is free of carrier elements. The end sections 20 and 22 of the vias 18 engage in correspondingly formed openings within the first printed circuit board 12 and the second printed circuit board 14 to establish an electrically conductive connection. The vias 18 thus establish an electrically conductive connection between the two printed circuit boards 12 and 14. The vias 18 are spaced apart from each other within the annular support element 16 on an imaginary ring 34. This means that all vias 18 are equidistant from a center point 36 of the imaginary ring 34. Preferably, the center point 36 of the imaginary ring 34 is the same as the center point 36 of the annular support element 16. This arrangement of the vias 18 on an imaginary ring 34 increases the vibration resistance of the printed circuit board assembly 10. Fig. 2 shows a cross-section through the printed circuit board assembly 10. The first printed circuit board 12 has a first top surface 24 and a second top surface 26 spaced apart from the first top surface 24 in a direction perpendicular to the plane of the first printed circuit board 12. Similarly, the second printed circuit board 14 has a first top surface 28 and a second top surface 30 spaced apart from the first top surface 28 in a direction perpendicular to the plane of the second printed circuit board 14. At least one electronic component 32 is arranged on each of the first top surface 24 and the second top surface 26 of the first printed circuit board 12, as well as on the first top surface 28 of the second printed circuit board 14, which faces the first printed circuit board 12. An electronic component 32 is preferably understood to be an electronic circuit and / or an electronic control. Preferably, but not limited thereto, the electronic component is a metal-oxide-semiconductor field-effect transistor (MOSFET), an application-specific integrated circuit (ASIC), and / or an insulated bipolar transistor with an insulated gate (IGBT module). The integration density of the electronic components 32 to be applied can be increased by the two adjacent printed circuit boards 12, 14, on which electronic components 32 are arranged on three top surfaces 24, 26, 28. The second top surface 30 of the second printed circuit board 14, which faces away from the first printed circuit board 12, is arranged on a base body 38. The base body 38 may be bonded to the second top surface 30, at least partially. The adhesive bond is preferably made using a thermally conductive adhesive. The base body 38 is made of a metal, in particular aluminum, and serves to dissipate heat generated by the electronic components 32 arranged on the first printed circuit board 12 and / or the second printed circuit board 14. Efficient heat dissipation ensures the reliability and performance of the printed circuit board assembly 10, especially at higher temperatures. The support element 16 is arranged between the two printed circuit boards 12 and 14 and rests against them in sections. A predefined distance between the two printed circuit boards 12 and 14 can be maintained via the support element 16. Because the vias 18 are arranged within the support element 16, a multiple of these vias can be placed on either the first printed circuit board 12 or the second printed circuit board 14 in a single placement operation of the support element 16, thus accelerating the manufacturing and / or assembly process. Furthermore, arranging the vias 18 within the support element 16 increases their rigidity, allowing them to be designed with less material, at least in certain sections.Thus, the manufacturing costs of the printed circuit board arrangement 10 can be reduced. Due to the section-by-section arrangement of the support element 16 and the first circuit board 12 or the second circuit board 14, at least section-by-section a gap 40 is also formed between the first circuit board 12 and the support element 16 and / or between the second circuit board 14 and the support element 16. Fig. 3 shows another cross-section through the printed circuit board assembly 10. The first printed circuit board 12 and / or the second printed circuit board 14 are at least partially overmolded and / or potted with a potting material 46, in particular a plastic material, so that the electronic components 32 arranged on the printed circuit boards 12, 14 can be protected from external media. This overmolding process can also be referred to as overmolding. Overmolding protects the electronic components 32 from aggressive media, such as preferably oil, in particular gear oil. Overmolding the printed circuit board assembly 10 eliminates the need for a housing to enclose the assembly, thereby reducing its dimensions and costs. It is further provided that a gap 44 formed between the first printed circuit board 12, the second printed circuit board 14, and the support element 16 is filled with a potting material 46, preferably a plastic material. By filling the gap 44 and / or cavity, the electronic components 32 of the first printed circuit board 12 and the second printed circuit board 14 projecting into it can be encased with the potting material 46, thus achieving increased media tightness of the printed circuit board assembly 10. Heat transfer can also occur via the potting to dissipate heat to the outside. Since the printed circuit boards 12 and 14 only partially contact the support element 16, the potting material 46 can enter the cavity and / or gap 44 via the gap 40. In this way, the gap 44 can be easily, at least partially, filled with the potting material 46. The potting material 46 of the space 44 is identical to the potting material 46 of the at least partial overmolding of the first and second printed circuit boards 12, 14. In this way, a media-tight printed circuit board assembly 10 can be provided in a single overmolding and / or potting process. Since only one potting process is required, the manufacturing costs of the printed circuit board assembly 10 can be reduced.

Claims

Printed circuit board arrangement (10) for a transmission control unit of a motor vehicle, comprising a first printed circuit board (12) having a first top surface (24) and a second top surface (26) spaced apart from the first top surface (24), and the first top surface (24) and the second top surface (26) being equipped with at least one electronic component (32), a second printed circuit board (14) spaced apart from the first printed circuit board (12), the second printed circuit board (14) having a first top surface (28) and a second top surface (30) spaced apart from the first top surface (28), wherein the first top surface (28) of the second printed circuit board (14) faces the first printed circuit board (12) and is equipped with at least one electronic component (32), and a plurality of vias (18) electrically connecting the first printed circuit board (12) and the second printed circuit board (14) to each other.wherein the vias (18) are arranged and / or formed at least partially in an annular carrier element (16), wherein the carrier element (16) is arranged between the two printed circuit boards (12, 14) and the printed circuit boards (12, 14) abut the carrier element (16) in sections, a cavity and / or space (44) is formed over the printed circuit boards (12, 14) and the carrier element (16), and at least one of the electronic components (32) arranged on the first printed circuit board (12) and / or the second printed circuit board (14) projects into the cavity and / or space (44), wherein projections in the axial direction of the carrier element (16) are formed at least partially on an end face of the carrier element (16), and the respective printed circuit board (12, 14) abuts the projections, and a gap exists between the respective printed circuit board (12, 14) and the The front face of the support element (16) is formed. Printed circuit board arrangement (10) according to claim 1, characterized in that the via elements (18) are arranged spaced apart from each other on a fictitious circular ring (34). Printed circuit board arrangement (10) according to one of the preceding claims, characterized in that the via elements (18) are arranged at regular and / or uniform intervals from each other. Printed circuit board arrangement (10) according to one of the preceding claims, characterized in that the first printed circuit board (12) and / or the second printed circuit board (14) is at least partially overmolded and / or potted with a potting material (46) and / or plastic material. Printed circuit board arrangement (10) according to one of the preceding claims, characterized in that the cavity and / or space (44) is at least partially filled with a potting material (46) and / or plastic material. Printed circuit board arrangement (10) according to claims 4 and 5, characterized in that the potting material (46) of the space (44) is the same as the potting material (46) of the at least partial overmolding of the first printed circuit board (12) and second printed circuit board (14). Printed circuit board arrangement (10) according to one of the preceding claims, characterized in that the first printed circuit board (12) and the second printed circuit board (14) each have through openings into which the via elements (18) engage for electrical connection of the two printed circuit boards (12, 14) to each other, and the potting material (46) is arranged at least section by section into the openings of the first printed circuit board (12) and / or the openings of the second printed circuit board (14). Printed circuit board arrangement (10) according to one of the preceding claims, characterized in that the second top surface (30) of the second printed circuit board (14) is arranged on a base body (38) and / or a cooling plate. Transmission control unit with a printed circuit board arrangement (10) according to one of the preceding claims. Use of a printed circuit board arrangement (10) according to one of claims 1 to 8 in a transmission control unit of a motor vehicle.

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