DE102017209180A1 - electronics assembly - Google Patents

Abstract

An electronic assembly (1) according to the invention comprises a printed circuit board (2) which carries a number of printed conductors, and a sensor element (4) which carries at least two connecting contacts (36) on a rear side (16) and a printed circuit board (2) fixed sensor housing (6) which surrounds the sensor element (4) pot-like from the back (16) of the sensor element (4), and which holds the sensor element (4) in its housing interior (20). The sensor housing (6) has for each terminal contact (36) of the sensor element (4) on a corresponding contact element (38) in the housing interior (20) with the respective terminal contact (36) is in galvanic connection and in a material of Sensor housing (6) is embedded so that it is free on the outside of the sensor housing (6) having a contact portion (40). Each of the contact sections (40) is also in electrical contact with one of the conductor tracks of the printed circuit board (2). Furthermore, the printed circuit board (2) is embedded in a plastic with at least partial enclosure of the sensor housing (6), wherein the housing interior (20) is sealed against penetration of the plastic by means of the inserted sensor element (4).

Description

The invention relates to an electronic assembly, in particular one which is used as a control unit for a transmission.

In the field of motor vehicles, electronic assemblies are used at various points. In most cases, such an electronic arrangement is a control device which serves, in particular, to execute a functionality, for example the control or regulation of a movement sequence of a movable vehicle part or the like. Frequently, in this case, such electronic assemblies are arranged in areas in which the electronic assembly is exposed to environmental influences such as the action of liquids, temperature fluctuations and mechanical influences (for example vibrations or vibrations). These environmental influences can lead to damage and in the worst case to failure of the respective electronic assembly. In particular, in the event that such an electronic assembly is a transmission control unit or an engine control unit (for example, a control of an internal combustion engine), the liquids with which the respective electronic assembly can come in contact are often (in particular opposite Rainwater) comparatively aggressive, d. H. especially corrosive media (eg geared fluids or oils, fuel etc.). If such aggressive liquids come into contact with electrically conductive elements (in particular electrical interconnects) of the respective electronics arrangement, in particular contact points between these elements and electronic components contacted with them may be damaged and thus the electrical contact may be lost. This leads to a failure of at least the electronic component, but usually the entire electronic assembly.

In order to protect the electronic components and the respective conductive elements, the respective electronic assembly is usually sealed with a housing. For this connection, however, contact elements for connection to an energy source and / or a higher-level controller must also be brought out of the medium-tight manner. In particular in the field of transmission control units, these regularly have different sensors, for example pressure sensors and / or temperature sensors for detecting operating states of the transmission, for example the transmission oil. As is known, these sensors must be free of the housing at least with their sensitive area. Regularly, a relatively high sealing effort must be operated to prevent entry of the above-described aggressive fluids through such housing bushings in the controller and thus to the electronic components out.

In addition to or in addition to the enclosure of the electronics assembly described above by means of a housing, it is also common to embed the electronic components of the electronic assembly and in particular a circuit board carrying these components in a plastic (for example, pour or encapsulate). However, the problem may be that the electrical contact points between the electronic components and the circuit board are wetted with the respective plastic. Due to different thermal expansion of plastic and metal (for example, the conductive elements), it can happen during operation at elevated and / or changing temperatures namely that the electrical contact point is released.

The invention has for its object to provide an electronic assembly with the highest possible reliability.

This object is achieved by an electronic assembly with the features of claim 1. Further advantageous and partly inventive embodiments and developments of the invention are set forth in the dependent claims and the description below.

The electronic assembly according to the invention comprises a printed circuit board which carries a number of printed conductors. Furthermore, the electronic assembly comprises a sensor element which carries at least two connection contacts on a rear side. In addition, the electronic assembly includes a sensor housing which is attached to the circuit board, and surrounds the sensor element pot-like from the back of the sensor element ago. In addition, the sensor housing holds the sensor element in its housing interior. The sensor housing further has, for each terminal contact of the sensor element, a corresponding contact element which is in galvanic connection with the respectively assigned terminal contact of the sensor element in the housing interior (of the sensor housing). In addition, the respective contact element is embedded in a material of the sensor housing such that it is free on the outside of the sensor housing with a contact portion, ie in particular protrudes from the material of the sensor housing. Each of the contact portions (the contact elements) is also in electrical contact with one of the conductor tracks of the printed circuit board in each case. The printed circuit board is also embedded in at least a partial inclusion of the sensor housing in a plastic, preferably with this plastic molded. The housing interior of the sensor housing is sealed by means of the sensor element inserted therein against penetration of the (in particular encapsulated) plastic.

The sensor housing thus serves to hold the sensor element on the circuit board and (by means of the respective contact element) for indirect contacting of the sensor element, specifically the respective terminal contact of the sensor element with the printed circuit board or with their associated conductor track. By this holder of the sensor element is advantageously a pre- or intermediate mounting unit (in particular comprising the circuit board, the sensor housing and the sensor element received therein) is formed, which is handled at least until embedding in the plastic, which preferably takes place in an injection molding by encapsulation with the plastic , facilitated. By embedding in the plastic next to the media-tight seal and a particularly stable and durable connection between the sensor housing and the circuit board is formed. Characterized in that the housing interior and thus the contact points arranged therein between the respective terminal contact and the associated contact element is sealed by means of the sensor element used, these contact points are advantageously protected against contact with the (embedding or Umspritzungs-) plastic. A risk that solves the electrical connection between the respective terminal contact and the associated contact element in the operation of the electronic assembly due to differential thermal expansion of the (embedding or Umspritzungs-) plastic and the material of the contact elements and the terminals, is thus advantageously reduced or excluded. Thus, advantageously, the reliability of the electronic assembly is increased.

In an expedient embodiment, the sensor element bears in particular with an annular collar (also referred to as a "collar") sealingly against an annularly closed contact surface of the sensor housing, so that the housing interior is sealed against penetration of the plastic. The annularly closed bearing surface preferably also forms a stop surface, by means of which the sensor element is aligned in the intended mounting state relative to the printed circuit board.

In a preferred embodiment, the sensor housing is made of a housing plastic, in particular injection-molded. This allows a particularly high degree of design freedom and at the same time low manufacturing costs for the sensor housing.

In a further preferred embodiment, the sensor housing formed in particular from the housing plastic has at least one snap hook (preferably three snap hooks) by means of which the sensor element is held in the housing cavity. The or the respective snap hook preferably forms a form-liquid connection between the sensor housing and the sensor element. For example, the or the respective snap hook engages on a side facing away from the support surface of the collar of the sensor element. Such a snap connection in this case represents a connection that is easy to implement, in particular by means of injection-molded plastic components and in particular also easy to install. For mounting, the sensor element is preferably inserted into the housing interior through an opening of the sensor housing designated as a sensor opening until the sensor element bears against the support surface and by means of of the respective snap hook (preferably under bias) is held against the support surface.

In a further expedient embodiment, the respective contact element is formed by a bent stamped grid, which is preferably injected into the sensor housing made of the housing plastic.

In order to reduce the overall height (or thickness) of the electronic assembly, the sensor housing is inserted through the printed circuit board in an advantageous embodiment by a corresponding opening whose cross section corresponds in particular approximately to the outer cross section of the sensor housing, and thus projects therethrough. "Approximately" is to be understood in this context such that the maximum outer dimension of the sensor housing at least partially corresponds to the inner dimension of the opening or this falls slightly below.

In a further expedient embodiment - in which the sensor housing is preferably likewise made of the housing plastic - the sensor housing has at least one further snap hook designated as a "clip hook" by means of which the sensor housing is held in a form-fitting manner on the printed circuit board by means of a snap connection. Preferably, the sensor housing has three clip hooks. The one or more clip hooks is in particular arranged on a base body of the sensor housing in such a way that the clip hook is inserted inside the opening through which the sensor housing protrudes through the printed circuit board, or through an associated opening separate from this opening. The sensor housing thus has two groups of snap hooks, wherein the first group for fixing the Sensor element in the housing interior and the second group, formed by the one or more clip hooks, for attaching the sensor housing to the circuit board.

In a further expedient embodiment, the contact section of the respective contact element is in particular materially connected to the associated conductor track of the printed circuit board. Preferably, the respective contact portion is welded to the associated conductor track or soldered to it. This creates a particularly stable and durable, in particular vibration-resistant connection between the respective contact section and the associated conductor track.

In a particularly expedient embodiment, in which the sensor housing protrudes through the corresponding opening of the printed circuit board, the sensor housing has a projection projecting on the outside to form a stop surface. With this projection, concretely with the stop surface of the sensor housing (in the intended mounting state) at the edge of the opening on the circuit board. This projection thus provides the insertion depth of the sensor housing into the opening of the printed circuit board and serves in particular as a stop against which the or the respective clip hooks the printed circuit board in bestimmungemäßen mounting state (in particular in the context of positive clip or snap connection).

Conveniently, the projection surrounds the sensor housing in an annular manner and forms a peripheral edge, which is referred to below as a flange ring.

In a preferred embodiment, the respective contact portion of the respective contact element is arranged within the abutment surface formed on this projection. Ie. the respective contact portion is in particular pin-like (pin-like) of the sensor housing within the stop surface. Preferably, the circuit board has a recess corresponding to the respective contact section or a corresponding opening into which the respective contact section protrudes in the intended mounting state, and in the region of which or the respective contact section is contacted with the associated conductor track of the circuit board. In this case, the stop surface is preferably flat on the circuit board and thereby unfolds advantageously a sealing effect, which prevents penetration of the (embedding or Umspritzungs-) plastic between the circuit board and the sensor housing up to the respective contact point between the contact portion and the associated conductor track ,

In a further preferred embodiment, the respective contact element of the sensor housing with the respective terminal contact of the sensor element is materially connected (in particular soldered or welded). In this case, the sensor housing preferably has a mounting opening on the rear side, through which the cohesive connection between the respective contact element and the associated connection contact can be produced. This mounting hole is after forming the cohesive connection between the respective contact element and the associated terminal contact by a housing cover - which forms a particular pot bottom for the sensor element pot-like surrounding sensor housing - closed. This means that the mounting opening is closed by the housing cover in the intended mounting state of the electronic assembly.

In an optional embodiment, the fluid connection between the respective contact element and the corresponding terminal contact of the sensor element is formed by laser welding. In this case, the housing cover is formed in an expedient development of a (at least for the wavelength of the welding laser used) laser-transparent plastic, so that the contact element with the associated terminal contact through the housing cover can be welded therethrough. In an alternative development, the sensor housing is formed on the back in one piece closed - d. H. the separately formed housing cover deleted - and injection molded as a whole from the laser-transparent plastic. In this case, the laser beam welding connection is formed by the one-piece (monolithic) formed with the base body pot bottom of the sensor housing. As a result, a particularly high density of the sensor housing is achieved.

In a further expedient embodiment, the sensor housing has on the inside a positioning aid which cooperates with a corresponding counterpart of the sensor element for unambiguous alignment of the sensor element in the housing interior. The positioning aid is, for example, a groove or a projection, in which a (corresponding to the counterpart) corresponding projection of the sensor element or engages in a corresponding groove of the sensor element.

In a further expedient embodiment, the sensor housing also on the outside a corresponding (second) positioning aid, which allows a clear alignment of the sensor housing in the opening of the circuit board (by means of a corresponding counterpart of the circuit board).

• 1 in einer perspektivischen Darstellung eine Elektronikanordnung,
• 2 und 3 in einer perspektivischen Darstellung bzw. in einer Ansicht auf eine Rückseite ein Sensorgehäuse der Elektronikanordnung,
• 4 in einer perspektivischen Darstellung einen Drucksensor der Elektronikanordnung,
• 5 in einer perspektivischen Darstellung ein Kontaktelement des Sensorgehäuses,
• 6 in einem perspektivischen und teildurchsichtigen Ausschnitt den in dem Sensorgehäuse angeordneten Drucksensor, und
• 7 und 8 jeweils in einer perspektivischen Darstellung die Elektronikanordnung in aufeinander folgenden Montagezuständen.

Hereinafter, an embodiment of the invention will be described in more detail with reference to a drawing. Show:

• 1 in a perspective view of an electronic assembly,
• 2 and 3 in a perspective view or in a view on a rear side of a sensor housing of the electronic assembly,
• 4 in a perspective view of a pressure sensor of the electronic assembly,
• 5 in a perspective view, a contact element of the sensor housing,
• 6 in a perspective and partially transparent cutout arranged in the sensor housing pressure sensor, and
• 7 and 8th each in a perspective view of the electronic assembly in successive assembly states.

Corresponding parts are always provided with the same reference numerals in all figures.

1 shows in a perspective view an electronic assembly 1 , which as a sensor unit forms part of a transmission control unit for a motor vehicle. The electronic assembly 1 includes a printed circuit board 2 on which a number of printed conductors, not shown for contacting various electronic components is applied. The circuit board 2 is designed as a printed circuit board ("PCB"). As a sensor element, the electronic assembly 1 a pressure sensor 4 on. To hold the pressure sensor 4 on the circuit board 2 at least during assembly of the electronic assembly 1 the latter includes a sensor housing 6 in which the pressure sensor 4 is received and held, and that on the circuit board 2 is attached. In the intended final production state (not shown in detail) is a bottom 8th the circuit board 2 and thus also the sensor housing 6 as well as the pressure sensor 4 with recess of a sensitive surface 10 of the pressure sensor 4 embedded in a plastic. Specifically, the pressure sensor 4 , the sensor housing 6 and the bottom 8th the circuit board 2 molded with this plastic in an injection molding process.

In 2 and 3 is the sensor housing 6 shown in more detail. The sensor housing 6 has a sectionally circular cylindrical body 12 of which a ring-shaped closed projection (as flange ring 14 designated) protrudes radially. This flange ring 14 points to a back 16 of the sensor housing 6 a stop surface 18 on, with the flange ring 14 in the assembled state according to 1 on the bottom 8th the circuit board 2 is applied. In the main body 12 of the sensor housing 6 is a housing interior 20 arranged in which in the intended mounting state of the pressure sensor 4 is included. To hold the pressure sensor 4 in the housing interior 20 has the sensor housing 6 at its front 22 three snap hooks 24 on, the pressure sensor in the intended mounting state 4 on a surrounding collar 26 of the pressure sensor 4 grip positively. In the housing interior 20 is also a paragraph 28 formed, that of the main body 12 annularly closed in the housing interior 20 protrudes. On this paragraph 28 , specifically on one by the paragraph 28 formed bearing surface 29 is the pressure sensor 4 with one on the collar 26 formed, correspond counter surface 30 on and is by means of snap hooks 24 against this paragraph 28 clamped. For clear alignment of the pressure sensor 4 has the sensor housing 2 serving as positioning aid grooves 32 on, in each case one of the collar ring 26 of the pressure sensor 4 protruding projection (also called "nose") 34 designated) engages.

The sensor housing 6 not only serves for mechanical mounting of the pressure sensor 4 on the circuit board 2 , but also for the indirect electrical contacting of the pressure sensor 4 , specifically from the back to the pressure sensor 4 arranged connection contacts 36 (see. 4 ) each having associated conductor tracks of the circuit board 2 , For this purpose, the sensor housing 2 three formed by a respective punched grid contact elements 38 on. These are as inserts in the injection molded from a (housing) plastic sensor housing 6 injected (cf. 2 . 3 and 6 ). The contact elements 38 each protrude with a free-end 39 such in the housing interior 20 before that they are properly in the housing interior 20 inserted pressure sensor 4 with the respectively assigned connection contact 36 of the pressure sensor 4 stay in contact. Each of the contact elements 38 is bent several times so that it with a contact section 40 from the stop surface 18 of the flange ring 14 pin-like (or pin-like) protrudes (see. 5 and 6 ). The respective contact section 40 protrudes in the intended mounting state in a corresponding hole in the circuit board 2 in there and is there by means of a solder joint with the associated conductor track of the circuit board 2 contacted (not shown). In 1 is the circuit board 2 For clarity, partially transparent, so that in the PCB 2 protruding contact sections 40 can be seen.

For a particularly stable contact between the connection contacts 36 and the contact elements 38 to allow these are welded together. Around in the housing interior 20 inserted pressure sensor 4 access to the contact elements 38 and the connection contacts 36 to allow, the sensor housing has 6 at the back one into the housing interior 20 leading mounting opening 42 on (cf. 3 and 7 ). This mounting hole 42 is in the intended mounting state by a housing cover 44 Media-tightly closed (cf. 8th ). To the respective contact point between the connection contacts 36 and the contact elements 38 during encapsulation of the sensor housing 6 To protect against wetting with the overmolded plastic, and thus the risk of damage to the respective contact point due to a different thermal expansion of the plastic and the contact elements 38 and the connection contacts 36 to avoid forming metals are the bearing surface 29 of the paragraph 28 of the sensor housing 6 and the counter surface 30 of the pressure sensor 4 designed in such a way (concretely sufficiently flat) that these plan rest on each other and thus the housing interior 20 from the front 22 forth from the pressure sensor 4 is sealed to prevent penetration of the overmolded plastic.

For mounting the sensor housing 6 and thus also the pressure sensor 4 on the circuit board 2 has the sensor housing 6 at its back 16 three more snap hooks (hereinafter referred to as clip hooks 46 referred to), in the intended mounting state, in which the sensor housing 6 through a corresponding opening 48 through the circuit board 2 is inserted through, at the edge of this opening 48 (form-fitting) are clipped. For mechanical securing of the sensor housing 6 on the circuit board 2 is the circuit board 2 also from her, the bottom 8th opposite top 50 molded with the plastic. This is done by the lid 44 penetration of plastic into the housing interior 20 prevented.

The object of the invention is not limited to the embodiment described above. Rather, other embodiments of the invention may be derived by those skilled in the art from the foregoing description. In particular, the described individual features of the invention and their design variants can be combined with each other in other ways. For example, as an alternative to the 7 and 8th the pressure sensor 4 in the sensor housing 6 fastened, with the contact elements 38 connected and then the housing interior 20 through the housing cover 44 closed before the sensor housing 6 on the circuit board 2 is attached.

LIST OF REFERENCE NUMBERS

1

electronics assembly

2

circuit board

4

pressure sensor

6

sensor housing

8th

bottom

10

sensitive area

12

body

14

flange

16

back

18

stop surface

20

Housing interior

22

front

24

snap hooks

26

collar

28

paragraph

29

bearing surface

30

counter surface

32

groove

34

nose

36

connection contact

38

contact element

39

free end

40

Contact section

42

mounting hole

44

housing cover

46

hook hook

48

opening

50

top

Claims (10)

Electronic assembly (1), comprising a printed circuit board (2) carrying a number of printed conductors, and a sensor element (4) carrying at least two connecting contacts (36) on a rear side, and a sensor housing attached to the printed circuit board (2) (6), which pot-like surrounds the sensor element (4) from the rear side of the sensor element (4), and which holds the sensor element (4) in its housing interior (20), wherein - the sensor housing (6) for each terminal contact (36) of the sensor element (4) has a corresponding contact element (38), the respective contact element (38) in the housing interior (20) is in galvanic connection with the respective terminal contact (36), - the respective contact element (38) is embedded in a material of the sensor housing (6) such that it is on the outside of the sensor housing (6) is free with a contact portion (40), - each of the contact portions (40) with one of the conductor tracks of the printed circuit board (2) is in galvanic contact, - the printed circuit board (2) with at least partial inclusion of the sensor housing (6) in one Plastic is embedded, and - the housing interior (20) is sealed by means of the inserted sensor element (4) against penetration of the plastic. Electronic arrangement (1) according to Claim 1 , wherein the sensor element (4) on a ring-shaped closed contact surface (29) of the sensor housing (6) sealingly rests against penetration of the plastic. Electronic arrangement (1) according to Claim 1 or 2 , wherein the sensor housing (6) is made of a housing plastic and at least one snap hook (24), by means of which the sensor element (4) in the housing interior (20) is supported. Electronic assembly (1) according to one of Claims 1 to 3 wherein the sensor housing (6) projects through a corresponding opening (48) through the printed circuit board (2). Electronic assembly (1) according to one of Claims 1 to 4 , wherein the sensor housing (6) is made of a housing plastic and at least one clip hook (46), by means of which the sensor housing (6) on the circuit board (2) is held positively by means of a snap connection. Electronic assembly (1) according to one of Claims 1 to 5 , wherein the respective contact portion (40) is integrally connected to the associated conductor track. Electronic assembly (1) according to one of Claims 4 to 6 in that the sensor housing (6) has a protrusion (14) projecting on the outside forming a stop face (18), and wherein the sensor housing (6) abuts the projection (14) on the edge of the opening (48) on the printed circuit board (2) , Electronic arrangement (1) according to Claim 7 , wherein the projection (14) surrounds the sensor housing (6) in an annular manner. Electronic arrangement (1) according to Claim 7 or 8th , wherein the respective contact portion (40) within the stop surface (18) is arranged. Electronic assembly (1) according to one of Claims 1 to 9 , wherein the respective contact element (38) of the sensor housing (6) with the respective terminal contact (36) of the sensor element (4) is integrally connected, and wherein the sensor housing (6) at the back of a mounting opening (42) for establishing the connection between the respective contact element (38) and the corresponding terminal contact (36), wherein the mounting opening (42) by a housing cover (44) is closed.

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