Sensor unit

Abstract

Sensor unit with a protective sleeve (20) in which at least one measuring cell (50) and a circuit carrier (60) with a substantially vertically oriented printed circuit board (40) are arranged, which comprises an electronic circuit (44) with at least one electronic and / or electrical component (44.1, 44.2), wherein the measuring cell (50) has at least one connection point (54), wherein the circuit carrier (60) has an internal interface (26) which taps at least one electrical output signal of the measuring cell (50) at the at least one connection point (54) and applies it to the electronic circuit (44), and wherein an external interface (28) provides an output signal of the electronic circuit (44), wherein the internal interface (26) is located at a first end (20.1) of the protective sleeve (20) and the external interface (28) is located at a second end (20.2) the protective sleeve (20) is formed, wherein the substantially vertically oriented printed circuit board (40) comprises a base carrier (42) which has a first joining geometry (42.3) on a first end face, which is joined to an outer joining geometry (62.1) on a base body (62) of the circuit carrier (60), wherein the outer joining geometry (62.1) on the base body (62) of the circuit carrier (60) comprises two receiving pockets, each of which comprises at least one first contact means (64.1) designed as a contact surface for electrical contacting the printed circuit board (40), wherein the base carrier (42) of the substantially vertically oriented printed circuit board (40) has first contact means (46.1) designed as a contact surface in the area of ​​the first joining geometry (42.3), which are joined to corresponding first contact means (64.1) in the area of ​​the outer joining geometry (62.1) form the internal electrical interface (26) on the base body (62) of the circuit carrier (60), wherein the base carrier (42) of the printed circuit board (40) has a second joining geometry (42.1) on a second end face, which is joined to a joining geometry (32.1) on a base body (32) of a support unit (30) arranged at the second end (20.2) of the protective sleeve (20), which supports the printed circuit board (40) against the protective sleeve (20).

Description

Prior ArtThe invention relates to a sensor unit.From WO 2009 / 007286 A2, for example, a connection unit for a pressure measuring cell is known. The known connection unit comprises a protective sleeve in which at least one measuring cell, which in particular detects a pressure of a hydraulic block, and a circuit carrier with a vertically positioned printed circuit board are arranged, which comprises an electronic circuit with at least one electronic and / or electrical component. The circuit carrier has a lower cylindrical region and an upper cylindrical region which are connected to one another via a rectangular central section, wherein the vertically positioned printed circuit board is arranged parallel to the rectangular central section between the two cylindrical sections of the circuit carrier. The pressure measuring cell has at least one connection point via which at least one electrical output signal of the pressure measuring cell can be tapped. The circuit carrier has an internal interface, which taps off the at least one electrical output signal of the pressure measuring cell and applies it to the electronic circuit, and an external interface, via which an output signal of the electronic circuit can be tapped off. Here, the internal interface is formed at a first end of the protective sleeve, and the external interface is formed at a second end of the protective sleeve. Furthermore, the circuit carrier has at least one external conductor track for contacting the connection point with the electronic circuit. In addition, at least one contact means is provided, by means of which an output signal of the electronic circuit can be tapped, wherein the electronic circuit is connected to the contact means via at least one external conductor track of the circuit carrier. The contacting between the pressure measuring cell and the circuit carrier or the circuit carrier and the circuit board or the electronic components takes place via corresponding conductive adhesive connections. To produce these conductive adhesive connections, the circuit carrier has conductive adhesive domes and the pressure measuring cell or the printed circuit board or the electronic components has corresponding conductive adhesive surfaces. The circuit carrier preferably consists at least of a plastic pre-injection molding made of galvanizable plastic and a second, non-galvanizable plastic, wherein the conductor tracks and the conductive adhesive domes are produced in a galvanic process as a metallic surface coating on the galvanizable plastic. For the detachable direct contacting of the connection unit with an add-on control device, the corresponding contact means are preferably designed as contact rivets, which are glued into provided openings connected to the conductor tracks by means of conductive adhesive.DE 10 2010 041 169 A1 discloses a pressure sensor for detecting a pressure of a medium, in particular for a brake device, which comprises a connecting flange with a fluid channel for connecting to the medium to be measured, a pressure measuring cell which is arranged at the end of the fluid channel, and a circuit carrier. In this case, the pressure measuring cell has a contact surface for contacting, which is arranged at an angle to a central axis of the pressure sensor.DE 10 2011 085 471 A1 discloses an arrangement for the direct contacting of contact means with a first contact means arranged on a contact carrier and a second contact means which acts on the first contact means with a predetermined contact force, and a corresponding connection device for a pressure measuring cell with such an arrangement for the direct contacting. The contact carrier consists at least of a plastic pre-molded part made of galvanizable plastic and a second, non-galvanizable plastic. In this case, the galvanizable plastic of the contact carrier has a predefined elastic behavior and the first contact means is formed by a metal layer having predefined dimensions, which can be applied to the galvanizable plastic of the contact carrier in a galvanic process. The elastic behavior of the electro-galvanized plastic and the dimensions of the metal layer under the action of the predetermined contact force cause a micro-depression for guiding the second contact means in the first contact means.DE 10 2009 045 790 A1 discloses a pressure sensor for detecting a pressure of a medium for a brake device. The pressure sensor comprises a connecting flange with a channel for connecting to the medium to be measured, a pressure measuring cell, which can be supplied with the pressure via the channel, and a printed circuit board, which is arranged in such a way that the printed circuit board lies in a longitudinal axis of the pressure sensor. The circuit board is equipped with electronic components on both sides. A central axis of the circuit board lies in the longitudinal axis of the pressure sensor. In addition, the pressure sensor comprises a circuit carrier which is mechanically connected to the connecting flange and the printed circuit board. For this purpose, the mechanical connection between the printed circuit board and the circuit carrier and / or between the connecting flange and the circuit carrier is designed as a mechanical plug connection. An electrical connection from the pressure measuring cell is made via the circuit carrier to the printed circuit board. For this purpose, the electrical connection between the pressure measuring cell and the circuit carrier and / or between the circuit carrier and the circuit board is designed as a bond connection or welded connection or soldered connection. In addition, the pressure sensor comprises a contact rivet carrier plate which is arranged on the printed circuit board at an end opposite the connecting flange. The contact rivet carrier plate has contact rivets for releasable electrical contact.Disclosure of the InventionThe sensor unit according to the invention according to the features of independent claim 1 has the advantage over the related art that it can be constructed in a particularly compact manner, since the circuit carrier only forms the internal interface and is arranged at the first end of the protective sleeve. The printed circuit board is simultaneously designed as a structural component within the protective sleeve and joined to the circuit carrier on the first end side. On the second end side, the printed circuit board is joined to a support unit which supports the printed circuit board against the protective sleeve. As a result, the overall height of the sensor unit can be reduced in an advantageous manner.Embodiments of the sensor unit according to the invention have a modular construction, so that a wide variety of sensors and customer interfaces can be implemented in an advantageous manner. Furthermore, the protective sleeve in conjunction with the support unit and the circuit carrier can provide integrated touch protection, which reduces the probability of failure during assembly or in the field. In addition, redundant contacting possibilities can be provided directly on the printed circuit board without effective external static contacting force in an advantageous manner for the external interface.The essence of the present invention consists in an intelligent combination of various previously discrete components or functions in one component. Such combined components have more degrees of freedom and can thus be used more flexibly. The use of a plurality of such combined components with multiple functions results in a sensor unit made of a modular composite which comprises the circuit carrier which makes electrical contact with the measuring cell, the vertically positioned printed circuit board which can preferably be fitted on both sides and is inserted and / or adhesively bonded into the circuit carrier, the support element which is preferably plugged and / or adhesively bonded onto the vertically positioned printed circuit board, and the protective sleeve with a flange which carries the measuring cell. An electronic circuit is arranged on the printed circuit board, which circuit carries out, for example, signal amplification and / or processing of a raw signal of the measuring cell. In addition, when using an application-specific integrated circuit (ASIC), a corresponding protective circuit can be provided on the printed circuit board. As an additional function, guide means for guiding external contact means can be provided in the support element, which guide means form the external interface with the second contact means of the printed circuit board.Embodiments of the present invention provide a sensor unit which has a protective sleeve in which at least one measuring cell, which in particular detects a pressure of a hydraulic block, and a circuit carrier with a printed circuit board which is placed substantially vertically are arranged, which printed circuit board can preferably be fitted on both sides and comprises an electronic circuit with at least one electronic and / or electrical component. The measuring cell has at least one connection point via which at least one electrical output signal of the measuring cell can be tapped. The circuit carrier has an internal interface which taps off the at least one electrical output signal of the measuring cell and applies it to the electronic circuit. An output signal of the electronic circuit can be tapped via an external interface. Here, the internal interface is formed at a first end of the protective sleeve, and the external interface is formed at a second end of the protective sleeve. In addition, the printed circuit board which is set essentially vertically comprises a base carrier which has a first joining geometry on a first end side, which joining geometry is joined to a base body of the circuit carrier by an outer joining geometry, wherein the base carrier of the printed circuit board has a second joining geometry on a second end side, which joining geometry is joined to a base body of a support unit arranged at the second end of the protective sleeve, which support unit supports the printed circuit board against the protective sleeve. The outer joining geometry comprises on the base body of the circuit carrier two receiving pockets, each of which comprises at least one first contact means for electrically contacting the circuit board. The base carrier of the printed circuit board placed essentially vertically has, in the region of the first joining geometry, first contact means which form the internal electrical interface with corresponding first contact means in the region of the outer joining geometry on the base body of the circuit carrier.The measures and developments listed in the dependent claims make advantageous improvements of the sensor unit specified in independent patent claim 1 possible.It is particularly advantageous that the base body of the circuit carrier can be designed as a cylinder with an inner joining geometry, which is adapted to an outer contour of the measuring cell and encloses the measuring cell. The circuit carrier preferably consists at least of a plastic pre-injection molding made of a galvanizable first plastic and a non-galvanizable second plastic, wherein conductor tracks and contact means are applied as a metallic surface coating to the galvanizable plastic by a galvanic process. Alternatively, the plastic pre-injection molding can be manufactured from the non-galvanizable second plastic and at least partially over-molded with the galvanizable first plastic. The circuit carrier can be produced, for example, by means of an MID-2K technique, i.e. the injection-molded circuit carrier (molded interconnected device) consists of two components which comprise a galvanizable first plastic which is at least partially over-molded with a non-galvanizable second plastic. Alternatively, the non-galvanizable second plastic can also be at least partially overmolded with the galvanizable first plastic. The partially protruding surfaces of the pre-molded part are coated with a metallic surface by means of an electroplating process, so that the outer conductor tracks and contact means are produced. The use of such an injection-molded MID circuit carrier is particularly well suited in the present application, since due to the improved design freedom and the integration of electrical and mechanical functions, the miniaturization of the connection unit for the sensor unit can be advanced. Alternatively, the circuit carrier can also be produced by an MID, which is directly structured by means of a laser. The MID circuit carrier then consists of an injection-molded part in which the locations of the conductor tracks and contact means are structured with the aid of a laser and are then coated with a metallic surface by means of a galvanic process. Alternatively, the circuit carrier can also be produced as a stamped grid injection-molded with plastic.The at least one first contact means can be connected, for example, via an external conductor track on the base body of the circuit carrier to at least one second contact means for electrically contacting the measuring cell.In a further advantageous embodiment of the sensor unit according to the invention, the first joining geometry of the printed circuit board can be designed as a recess in the base carrier, which recess is bounded on two opposite sides in each case by a guide limb, wherein the two guide limbs of the first joining geometry of the printed circuit board are each joined to a receiving pocket of the outer joining geometry of the printed circuit carrier. In this case, the guide legs can be guided via inner guide edges in the receiving pockets and / or via outer guide edges on an inner contour of the protective sleeve. By appropriate shaping of the receiving pockets, the printed circuit board can have a predeterminable small angle of inclination with respect to the vertical vertical axis of the sensor unit, if required.In a further advantageous embodiment of the sensor unit according to the invention, the base carrier of the printed circuit board placed substantially vertically can have second contact means in the region of the second joining geometry, which contact means can be contacted by corresponding external contact means and form the external electrical interface. The second contact means are preferably designed as redundant contact surfaces, which are respectively arranged on an upper side and an underside of the base carrier of the printed circuit board. The external contact means can be designed, for example, as contact clamps with two legs, which are pushed onto the second contact means designed as redundant contact surfaces in such a way that a contact force acts perpendicular to the insertion direction of the base carrier of the printed circuit board, so that the remaining printed circuit board, in particular the internal interface, remains force-free. Due to the redundant design of the second contact means and the contact force acting perpendicular to the insertion direction of the base carrier, a non-ideal contacting, which is caused, for example, by contamination, does not yet lead to the failure of the electrical and / or mechanical connection of the external interface. Since a greater contact force is also possible due to the described contact geometry, expensive contact materials, such as gold, may be dispensed with.In a further advantageous embodiment of the sensor unit according to the invention, the support unit can have guide means for guiding the external contact means. As a result, the external interface can be variably adapted to different customer requirements via the execution of the support unit.An exemplary embodiment of the invention is illustrated in the drawings and is explained in more detail in the description below. In the drawings, like reference numerals designate components or elements that perform like or analogous functions.Brief Description of the DrawingsFIG. 1 shows a schematic perspective illustration of a sensor unit according to the invention. FIG. 2 shows a schematic perspective illustration of a sensor unit according to the invention without a protective sleeve. FIG. 3 shows a schematic perspective illustration of a sensor carrier with a fastening flange and a measuring cell for the sensor unit according to the invention from FIG. 1 or FIG. 2 before the joining of the measuring cell to the sensor carrier. FIG. 4 shows a schematic perspective illustration of the sensor carrier and a circuit carrier for the sensor unit according to the invention from FIG. 1 or FIG. 2 before the circuit carrier is joined to the sensor carrier. FIG. 5 shows a schematic perspective illustration of the sensor carrier with the joined circuit carrier for the sensor unit according to the invention from FIG. 1 or FIG. 2. FIG. 6 shows a schematic perspective illustration of the sensor carrier with a joined protective sleeve before joining the circuit board joined with a support unit for the sensor unit according to the invention of FIG. 1 or 2. FIG. 7 shows a schematic perspective illustration of the sensor unit according to the invention from FIG. 1 or FIG. 2 after the joining of the printed circuit board without a support unit and without a protective sleeve. FIGS. 8 and 9 each show a schematic perspective illustration of a printed circuit board for the sensor unit according to the invention from FIG. 1 or FIG. 2. FIG. 10 shows a schematic perspective illustration of an external contact means for the sensor unit according to the invention from FIG. 1 or FIG. 2. FIG. 11 shows a schematic perspective illustration of the printed circuit board for the sensor unit according to the invention from FIG. 1 or FIG. 2 with external contact means pushed on. FIG. 12 shows a schematic detailed illustration from FIG. 11 from a different angle of view. FIG. 13 shows a schematic perspective illustration of an upper section of the sensor unit according to the invention from FIG. 1 or FIG. 2 with external contact means pushed on.Embodiments of the InventionAs can be seen from FIGS. 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12 to 13, the illustrated exemplary embodiment of the sensor unit 1 according to the invention comprises a protective sleeve 20 in which at least one measuring cell 50, which in particular detects a hydraulic pressure of a solenoid valve-controlled fluid in a vehicle brake system, and a circuit carrier 60 with a substantially vertically positioned printed circuit board 40 are arranged. The printed circuit board 40 is preferably designed such that it can be fitted on both sides and comprises an electronic circuit 44 having at least one electronic and / or electrical component 44.1, 44.2, which performs, for example, signal amplification and / or processing of a raw signal of the measuring cell 50. In the exemplary embodiment shown, the electronic circuit 44 comprises an application-specific integrated circuit (ASIC) 44.1 and a corresponding protective circuit. The measuring cell 50 converts the hydraulic pressure into at least one electrical output signal and has at least one connection point 54, via which the at least one electrical output signal of the measuring cell 50 can be tapped. The circuit carrier 60 has an internal interface 26 which taps off the at least one electrical output signal of the measuring cell 50 and applies it to the electronic circuit 44. In addition, an output signal of the electronic circuit 44 can be tapped via an external interface 28. In this case, the internal interface 26 is formed at a first end 20.1 of the protective sleeve 20, and the external interface 28 is formed at a second end 20.2 of the protective sleeve 20. The protective sleeve 20 protects the interior of the sensor unit 1 from excessive mechanical stress. In addition, the printed circuit board 40 which is set essentially vertically comprises a base carrier 42 which has, on a first end side, a first joining geometry 42.3 which is joined to an outer joining geometry 62.1 on a base body 62 of the circuit carrier 60, and, on a second end side, a second joining geometry 42.1 which is joined to a joining geometry 32.1 on a base body 32 of a support unit 30 which is arranged on the second end 20.2 of the protective sleeve 20 and supports the printed circuit board 40 against the protective sleeve 20.As can be further seen from FIGS. 1 and 2, the protective sleeve 20 in the exemplary embodiment shown is designed as a hollow cylinder and has a step 22 at the first end 20.1. The protective sleeve 20 is joined at the stepped first end 20.1 to a sensor carrier 10 which has a fastening flange 12 and a measurement connection 18 which, in the exemplary embodiment of the sensor unit 1 shown, is designed as a pressure sensor unit as a self-clinching connection. The fastening flange 12 has a flange edge 12.1, on which the protective sleeve 20 is supported and by means of which the sensor unit 1 can be caulked to a fluid block, not shown. In addition, the fastening flange 12 comprises a stepped flange surface 14, wherein the step 16 between the flange edge 12.1 and the flange surface 14 in the exemplary embodiment shown is used as a connecting region on which the protective sleeve 20 is pressed. In addition, the protective sleeve 20 can be welded to the fastening flange 12 at the transition of the step 16 to the flange edge 12.1. The height of the step 22 or constriction of the protective sleeve 20 is selected such that the caulking of the sensor unit 1 with the fluid block, not shown, via the flange edge 12.1 is possible by means of a caulking tool. Due to the stepped embodiment at the lower first end 20.1 of the protective sleeve 20, the fastening flange 12 of the sensor carrier 10 can advantageously be embodied with a smaller diameter. Alternatively, the protective sleeve 20 can also be designed without a step 22.As can be further seen from FIGS. 2, 3, 4, 5, 6 to 7, the base body 62 of the circuit carrier 60 in the exemplary embodiment shown is designed as a cylinder with an inner joining geometry 62.2, which is adapted to an outer contour 56 of the measuring cell 50 and encloses the measuring cell 50. The outer joining geometry 62.1 on the base body 62 of the circuit carrier 60 comprises two receiving pockets, each of which comprises at least one first contact means 64.1 for electrically contacting the circuit board 40. The at least one first contact means 64.1 is connected via an external conductor track 64.2 on the base body 62 of the circuit carrier 60 to at least one second contact means 64.3 for electrically contacting the measuring cell 50. The first joining geometry 42.3 of the printed circuit board 40 is designed as a cutout in the base carrier 42, which is bounded on two opposite sides in each case by a guide leg 42.4. The two guide legs 42.4 of the first joining geometry 42.3 of the printed circuit board 40 are each joined to a receiving pocket of the outer joining geometry 62.1 of the circuit carrier 60. In the exemplary embodiment shown, the two guide legs 42.4 of the printed circuit board 40 are guided via inner guide edges 42.5 in the receiving pockets 62.1 of the circuit carrier 60. Additionally or alternatively, the guide legs 42.4 of the printed circuit board 40 can also be guided via outer guide edges on an inner contour 24 of the protective sleeve 20. By appropriate shaping of the receiving pockets 62.1, the printed circuit board 40 can have a predeterminable small angle of inclination with respect to the vertical vertical axis of the sensor unit 1, if necessary.As can be further seen from FIGS. 2, 3, 4, 5, 6 to 7, the base carrier 42 of the printed circuit board 40 placed substantially vertically has, in the region of the first joining geometry 42.3, first contact means 46.1, which form the internal electrical interface 26 with corresponding first contact means 64.1 in the region of the outer joining geometry 62.1 on the base body 62 of the circuit carrier 60. In the region of the second joining geometry 42.1, the base carrier 42 of the vertically placed printed circuit board 40 has second contact means 46.2, which can be contacted by corresponding external contact means 70 shown in FIG. 10 and form the external electrical interface 28.As can be further seen from FIGS. 1 and 2, the base body 32 of the support unit 30 has a receiving opening 32.1 for the printed circuit board 40. The support unit 30 is inserted at the second end 20.2 of the protective sleeve 20 so as to be movable in play and is pushed onto the printed circuit board 40 via the receiving opening 32.1. By means of an outer contour 34, the support unit 30 supports the printed circuit board 40 against an inner contour 23 of the protective sleeve 20. In addition, the support unit 30 has guide means 32.2, which are designed as contact-receiving pockets, for guiding the external contact means 70.As can be further seen from FIGS. 3, 4 to 5, the fastening flange 12 can be pressed or connected to the fluid block, not shown, for example by means of a self-clinching connection 18. In addition to the above-described connecting region 16 for pressing on or welding the protective sleeve 20, connecting openings 14.1 are introduced into the flange surface 14, which openings receive connecting pins 66 arranged on the circuit carrier 60 in order to enable a rotationally secure connection of the circuit carrier 60 to the sensor carrier 10. In order to join the circuit carrier 60 to the sensor carrier 10, an adhesive layer 61 is applied to the flange surface 14 in the exemplary embodiment shown. Of course, other suitable connection techniques known to the skilled person can also be used to join the circuit carrier 60 to the sensor carrier 10 in a rotationally secure manner.As can be further seen from FIGS. 3, 4 to 5, the measuring cell 50 designed as a pressure measuring cell in the exemplary embodiment shown is placed on a tubular carrier 11 of the fastening flange 12 in such a way that a measuring membrane 50.1 of the measuring cell 50 is deformed depending on the pressure of the fluid in the hydraulic block. The deformation of the measuring membrane 50.1 is detected by a measuring bridge 52. The measuring bridge 52 is connected to four contact points 54, which in the exemplary embodiment shown are each electrically connected via bonding wires 58 to the second contact means 64.3 of the circuit carrier 60 embodied as bonding surfaces. The circuit carrier 60 is preferably formed using so-called MID-2K technology. It is produced as an injection-molded circuit carrier 60 made of plastic in MID technology (moulded interconnected device), in particular by two-component injection molding. Three-dimensional circuit structures can be realized by MID technology. A plastic pre-injection molded part made of a galvanizable first plastic is partially overmolded with a non-galvanizable second plastic. Alternatively, the non-galvanizable second plastic can also be at least partially overmolded with the galvanizable first plastic. The partially protruding surfaces of the pre-molded part are coated with a metallic surface by means of an electroplating process, so that the outer conductor tracks 64.2 and the first and second contact means 64.1, 64.2 are produced. The circuit carrier 60 is distinguished in particular by the integration of electrical and mechanical functions through a high degree of freedom of design. As a result, the sensor unit 1 can be constructed in a particularly compact manner. In the exemplary embodiment shown, the circuit carrier 60 consists at least of a plastic pre-injection molding made of a galvanizable first plastic and a non-galvanizable second plastic. On an end face of the circuit carrier 60 are arranged the second contact means 64.3, which are designed as bonding surfaces and are connected via external conductor tracks 64.2 to the corresponding first contact means 64.1, which are designed as contact surfaces and are arranged in the receiving pockets of the outer joining geometry 62.1. The first contact means 64.1, the conductor tracks 64.2 and the second contact means 64.3 of the circuit carrier 60 are each designed as a metal layer with predetermined dimensions and are applied to the electrogalvanizable plastic of the circuit carrier 60 in an electroplating process.During the production of the sensor unit 1, the measuring cell 50 is welded to the sensor carrier 10. Subsequently, the circuit carrier 60 is pressed into the connecting openings 14.1 via the connecting pins 66 and glued on, wherein the holding adhesive layer 61 is introduced between the flange surface 14 and a base surface of the circuit carrier 60. As can be seen from FIG. 6, after the holding adhesive layer 61 has cured, the protective sleeve 20 is pressed on and optionally fixed by means of spot welding.As can be further seen from FIGS. 6 and 7, the conductive plate 40 is inserted into the receiving pockets of the outer joining geometry 62.1 on the base body 62 of the circuit carrier 60 and, if appropriate, fixed there with holding adhesive 5 and conductive adhesive 3 in order to ensure an electrically conductive connection between the circuit carrier 60 and the circuit board 40 and to fix the circuit board 40. As can be further seen from FIG. 6, the holding adhesive 5 is introduced at base surfaces of the receiving pockets 62.1 of the circuit carrier 60 and the conductive adhesive 3 is applied to the first contact means 46.1 of the printed circuit board 40 embodied as contact surfaces. The support unit 30 can be plugged onto the printed circuit board 40 before or after the joining of the printed circuit board 40. In addition, a mechanical and / or electrical connection between the printed circuit board 40 and the support unit 30 can optionally be produced by means of conductive or retaining adhesives. In order to ensure a secure electrical and mechanical connection between the printed circuit board 40 and the circuit carrier 60 at the internal interface 26, the support unit 30 can be plugged on at the internal interface 26 before the conductive or holding adhesive cures, in order to ensure a force-free or stress-free curing of the conductive adhesive 3 and of the holding adhesive 5 at the internal interface 26 by supporting the printed circuit board 40 on the inner contour 24 of the protective sleeve 20.As can be further seen from FIGS. 8 and 9, the printed circuit board 40 has the planar base carrier 42 with first contact means 46.1 embodied as contact surfaces and second contact means 46.2 embodied as redundant contact surfaces, which are arranged on both sides of the base carrier 42. As can be further seen from FIGS. 8 and 9, the base carrier 42 of the printed circuit board 40 is narrower in the region of the external interface 28 for forming the second joining geometry 42.1 with a first guide edge and has a stop shoulder 42.2, against which the support unit 30 bears when the second end side of the printed circuit board 40 is received by the receiving opening 32.1 of the support unit 30 in order to guide the support unit 30 and to fix it on the printed circuit board 40. Alternatively, the stop can also be realized in the upper region of the support unit 30 by limiting the depth of the receiving opening 32.1 in the support unit 30 for receiving the second joining geometry 42.1 of the printed circuit board 40.As can be further seen from FIGS. 8 and 9, the base carrier 42 of the printed circuit board 40 has, in the region of the internal interface 26 for forming the first joining geometry 42.3, a fork shape with the two guide legs 42.4 and two second guide edges 42.5, which delimit a cutout. As already explained above, the guide legs 42.4 of the printed circuit board 40 can additionally or alternatively also be guided via outer guide edges on the inner contour 24 of the protective sleeve 20. The fork shape of the first joining geometry 42.3 of the printed circuit board 40 is adapted to the receiving pockets of the outer guiding geometry 62.1 of the circuit carrier 60, so that the base carrier 42 of the printed circuit board 40 can be inserted into the circuit carrier 60 and fixed. In the exemplary embodiment shown, the printed circuit board 40 is equipped on both sides and has at least two layers.As can be further seen from FIGS. 10, 11, 12 to 13, the second contact means 46.2 of the printed circuit board 40 in the exemplary embodiment shown are designed as redundant contact surfaces, which are arranged in each case on an upper side and a lower side of the base carrier 42 of the printed circuit board 40. In addition, in the exemplary embodiment shown, the external contact means 70 are designed as a contact clip having two limbs 72, which are pushed onto the second contact means 46.2, which are designed as redundant contact surfaces, in such a way that a contact force Fk acts perpendicularly to the insertion direction of the base carrier 42 of the printed circuit board 40. The external contact means 70 designed as an elastic contact clip or contact fork are geometrically shaped in such a way that the external contact means 70 can be plugged onto the second contact means 46.2, designed as contact surfaces, of the printed circuit board 40 and contact the latter from both sides. Thus, for example, rounded insertion regions can be provided on the external contact means 70. The respective contact regions 74 of the external contact means 70 designed as an elastic contact clip or contact fork are located laterally in the "fork prongs" or "fork legs" 72 so that the contact force Fk can be applied transversely to the inserted printed circuit board 40 and thus the remaining printed circuit board 40, in particular the internal interface, remains force-free. Since this geometry allows a greater contact force Fk, expensive contact materials such as gold can be advantageously dispensed with.The sensor unit described is suitable in particular for use as a pressure sensor in brake systems of motor vehicles, but is not restricted thereto. In particular in brake systems of the premium class, a large number of pressure sensors are used with only limited installation space. A pressure sensor unit that is minimized in installation space is therefore particularly suitable for this application.

Claims

Sensor unit having a protective sleeve (20), in which at least one measuring cell (50) and a circuit carrier (60) having a printed circuit board (40) placed substantially vertically are arranged, which comprises an electronic circuit (44) having at least one electronic and / or electrical component (44.1, 44.2), wherein the measuring cell (50) has at least one connection point (54), wherein the circuit carrier (60) has an internal interface (26), which taps off at least one electrical output signal of the measuring cell (50) at the at least one connection point (54) and applies it to the electronic circuit (44), and wherein an external interface (28) provides an output signal of the electronic circuit (44), wherein the internal interface (26) is formed at a first end (20.1) of the protective sleeve (20) and the external interface (28) is formed at a second end (20.2) of the protective sleeve (20), wherein the essentially perpendicular printed circuit board (40) comprises a base carrier (42), which has a first joining geometry (42.3) on a first end side, which joining geometry is joined to an outer joining geometry (62.1) on a base body (62) of the circuit carrier (60), wherein the outer joining geometry (62.1) on the base body (62) of the circuit carrier (60) comprises two receiving pockets, which each comprise at least one first contact means (64.1) designed as a contact surface for electrically contacting the printed circuit board (40), wherein the base carrier (42) of the essentially perpendicular printed circuit board (40) has first contact means (46.1) designed as a contact surface in the region of the first joining geometry (42.3), which form the internal electrical interface (26) with corresponding first contact means (64.1) in the region of the outer joining geometry (62.1) on the base body (62) of the circuit carrier (60), wherein the base carrier (42) of the printed circuit board (40) has a second joining geometry (42.1) on a second end side, which is joined with a joining geometry (32.1) on a base body (32) of a support unit (30) arranged on the second end (20.2) of the protective sleeve (20), which support unit supports the printed circuit board (40) against the protective sleeve (20).Sensor unit according to Claim 1, characterized in that the base body (62) of the circuit carrier (60) is designed as a cylinder having an inner joining geometry (62.2), which is adapted to an outer contour (56) of the measuring cell (50) and encloses the measuring cell (50).Sensor unit according to Claim 1 or 2, characterized in that the at least one first contact means (64.1) is connected via an external conductor track (64.2) on the base body (62) of the circuit carrier (60) to at least one second contact means (64.3) for electrically contacting the measuring cell (50).Sensor unit according to one of Claims 1 to 3, characterized in that the first joining geometry (42.3) of the printed circuit board (40) is designed as a cutout in the base carrier (42), which cutout is bounded on two opposite sides in each case by a guide limb (42.4), wherein the two guide limbs (42.4) of the first joining geometry (42.3) of the printed circuit board (40) are in each case joined to a receiving pocket of the outer joining geometry (62.1) of the circuit carrier (60).Sensor unit according to one of Claims 1 to 4, characterized in that the base carrier (42) of the printed circuit board (40) which is placed substantially vertically has, in the region of the second joining geometry (42.1), second contact means (46.2), which can be contacted by corresponding external contact means (70) and form the external electrical interface (28).Sensor unit according to Claim 5, characterized in that the second contact means (46.2) are designed as redundant contact surfaces which are arranged in each case on an upper side and an underside of the base carrier (42) of the printed circuit board (40).Sensor unit according to claim 5 or 6, characterised in that the support unit (30) has guide means (32.2) for guiding the external contact means (70).Sensor unit according to one of Claims 5 to 7, characterized in that the external contact means (70) are designed as a contact clip having two limbs (72), which are pushed onto the second contact means (46.2), designed as redundant contact surfaces, in such a way that a contact force (Fk) acts perpendicularly to the insertion direction of the base carrier (42) of the printed circuit board (40).Sensor unit according to one of Claims 1 to 8, characterized in that the at least one measuring cell (50) detects a pressure of a hydraulic block.

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