Electrical circuit of a motor vehicle

Abstract

The invention relates to an electrical circuit (8) of a motor vehicle (2), comprising a printed circuit board (10) on which a spring contact (12) is arranged, the spring contact having two contact tongues (20) extending away from the printed circuit board (10) and being elastically bendable relative to each other. The printed circuit board (10) has a recess (30) that opens between the two contact tongues (20). The invention further relates to a method (46) for manufacturing an electrical circuit (8).

Description

The invention relates to an electrical circuit of a motor vehicle, having a printed circuit board on which a spring contact is arranged. The invention further relates to a method for producing an electrical circuit.Motor vehicles, such as passenger cars (passenger cars), usually have a plurality of electrical circuits, by means of which, for example, in each case one actuator is controlled and / or regulated. In this case, it is possible for the electrical circuit to be designed as an electronic system or electrical system. The actuator is, for example, an electric motor of an electric motor-driven adjusting drive, which is operated by means of the electric circuit according to current requirements. Such an electromotive adjustment drive is, for example, an electric lock in which a lock pawl or a latch is adjusted by means of the electric motor, so that a movement of a door having the electric lock with respect to a body of the motor vehicle is made possible or prevented.Such an electrical circuit usually has a printed circuit board, to which different electrical and / or electronic components are fastened, and which are suitably interconnected to one another by means of corresponding conductor tracks of the printed circuit board. For the purpose of current supply and / or for the purpose of signal exchange, it is necessary for at least some of the conductor tracks to be electrically connected to further components, such as busbars. For this purpose, so-called spring contacts soldered to the printed circuit board are usually used, which have two contact tongues which can be elastically bent relative to one another. In the non-mounted state, the two contact tongues bear mechanically against one another. For electrical contacting with the busbar (stamped grid), a blade contact of the busbar is introduced between the latter, the contact tongues being spread open. Due to the elastic deformability, these in the assembled state bear on both sides in a force-fit manner on the blade contact, so that a secure electrical contact is provided.For protection against mechanical damage or environmental influences, the printed circuit board is usually arranged within a housing. During assembly, the printed circuit board is introduced via an opening of the housing, which is subsequently closed by means of a cover. If the electrical circuit is designed as an integrated electronic system, the printed circuit board sits directly close to the electric motor in the same module. Thus, no long / shielded cables are required, and electrical signals can be passed directly to the printed circuit board by means of the stamped grid or electrical energy by means of the busbar in a short path. Depending on the installation situation, it is possible here for the blade contact which is intended to be electrically contacted with the spring contact to be located on the side of the housing opposite the opening. Thus, after the mounting of the blade contact and the spring contact, the opening no longer makes it visible owing to the existing printed circuit board, and it is not possible to visually check whether the blade contact has been correctly inserted into the spring contact, that is to say that a correct electrical connection has been established.In order to ensure that the electrical contacting is present, it is possible, for example, to choose comparatively low manufacturing tolerances in the individual components of the electrical circuits, which is why waste and thus manufacturing costs are increased. Alternatively, as soon as the electrical circuit is mounted, it is suitably energized and the functions carried out therewith are checked. Alternatively, an electrical voltage is applied to corresponding terminals of the electrical circuit and, for example, a resulting current flow is determined. However, it is possible here that, when the printed circuit board is inserted into the housing, for example, the spring contacts and / or the blade contact are bent in an undesired manner, and the blade contact bears against the spring contact only on the outside. Thus, although electrical contacting is present, it is not reliable over the service life. If the checking of the electrical circuit is now carried out, this behaves essentially as desired. However, if vibrations or the like occur during operation of the motor vehicle, it is possible for the blade contact to be released from the contact tongues for a short time or completely, so that the electrical contacting is at least temporarily canceled. Thus, the behavior of the electric circuit is erroneous.The object of the invention is to specify a particularly suitable electrical circuit of a motor vehicle and a particularly suitable method for producing an electrical circuit, wherein production costs are advantageously reduced, and wherein reliability is suitably increased.With regard to the electrical circuit, this object is achieved according to the invention by the features of claim 1 and with regard to the method by the features of claim 10. Advantageous refinements and refinements are the subject matter of the respective dependent claims.The electrical circuit is a component of a motor vehicle in the assembled state and is suitable, in particular provided and configured, for this purpose. The motor vehicle is in particular land-bound and preferably multi-lane. In this case, it is suitably possible to position the motor vehicle substantially freely, in particular on a roadway. For this purpose, the motor vehicle expediently has corresponding wheels. In summary, it is preferably possible to position the motor vehicle on land substantially independently of other circumstances. In other words, the motor vehicle is suitably not rail-guided. The motor vehicle is preferably a passenger car (passenger car) or a commercial vehicle, such as a truck (truck) or bus.For example, the electrical circuit is a component of a main drive of the motor vehicle. The main drive is operated and / or controlled / regulated, for example, by means of the electrical circuit. Particularly preferably, however, the electrical circuit is a component of an auxiliary unit of the motor vehicle. The auxiliary unit does not serve directly for the propulsion of the motor vehicle and thus does not represent the main drive in particular. However, the auxiliary unit serves, for example, for operating the main drive and / or for providing comfort functions for a user of the motor vehicle.For example, the auxiliary unit is purely electric / electronic, and the electrical circuit is, for example, an onboard computer or an infotainment system. Alternatively, the auxiliary unit has, for example, an actuator. The actuator expediently comprises an electric motor or is formed by means of it. The electric motor is, for example, a commutator motor or, particularly preferably, a brushless direct current motor (BLDC). Alternatively, the actuator is a linear actuator. Preferably, a rotational speed, a torque, a position and / or a rotational direction of the electric motor is set by means of the electric circuit.For example, the auxiliary unit is a pump and / or, in the assembled state, is a component of a brake system, such as an electric brake pedal. Particularly preferably, the auxiliary unit is an electromotive adjustment drive which has an adjustment part driven along an adjustment path by means of the electric motor or at least the actuator. Between the adjusting part and the electric motor, a gear, such as a worm gear, is arranged mechanically. Alternatively or in combination therewith, a cable drum, a spindle or the like is arranged mechanically between the electric motor and the adjusting part.For example, the electromotive adjustment drive is an electromotive window lifter or an electromotive door adjustment, so that a window pane or a door is adjusted during operation of the auxiliary unit. Alternatively, the adjusting part is, for example, a door handle, and the door handle is moved out of a recess or into the latter when required, that is to say when a corresponding request is present. In a further alternative, the auxiliary unit is an electric (door) lock. In this case, the actuator is designed in particular as an electric motor, by means of which a pawl or a latch is driven / moved. This(s) can be brought into engagement with a counterpart by means of the electric motor, if required, so that the door lock is locked. The counterpiece is, for example, a depression or the like, which is expediently retained on the vehicle body side in the assembled state, provided that the latch / latch is mounted on a door.The electrical circuit is, for example, an electronic system, so that it comprises at least one electronic component, such as a microprocessor. In particular, the electrical circuit is an integrated electronic system. Alternatively, the electrical circuit is, for example, an electric system which is constructed in particular only from electrical components. The electrical circuit has a printed circuit board to which, in particular, any electrical / electronic components are connected. Preferably, the components are at least partially soldered to the circuit board and / or the components are electrically contacted to one another by means of possible conductor tracks of the circuit board. The printed circuit board thus expediently has one or more conductor tracks which are manufactured, for example, from an aluminum or preferably from a copper. The conductor tracks are in particular connected to a surface of a body of the printed circuit board or embedded therein, for example. The body here is expediently made of a glass fibre-reinforced epoxy resin. The printed circuit board is preferably designed to be completely or partially rigid and / or planar.The electrical circuit further includes a spring contact disposed on the circuit board. In particular, the spring contact is fastened to the printed circuit board and / or electrically contacted to the printed circuit board. The spring contact has two contact tongues which extend away from the printed circuit board. For example, the two contact tongues are identical in construction to one another and in particular mirror-image to one another. Alternatively, the two contact tongues are different from each other. At least however, one of the two contact tongues, preferably both, is made of an electrically conductive material and is suitably electrically contacted with the printed circuit board. Expediently, the printed circuit board is arranged substantially in a plane / surface, and the contact tongues are suitably arranged substantially perpendicular to this plane.The two contact tongues are elastically bendable with respect to each other. In particular, the contact tongues are made of an elastic material, such as spring steel. In particular, the contact tongues run substantially parallel to one another and are preferably inclined to one another by an angle which is less than 20°, 10° or 5°. If the spring contact is unloaded and / or not electrically contacted with further components, such as a blade contact, the free ends of the contact tongues spaced apart from the printed circuit board in particular bear directly against one another mechanically. Due to the elastic bending ability, it is possible in particular to space the free ends from one another, wherein, if no force acts any longer on the free ends, they again reach the original position. In particular, the contact tongues are designed in such a way that a blade contact or another contact can be inserted between them, wherein the respective contact is provided, for example, by means of a busbar. In summary, it is thus possible by means of the spring contact to make electrical contact with a component which is separate from the printed circuit board, wherein this component, which is in particular configured as a blade contact, is introduced between the contact tongues.The printed circuit board has a cutout which thus projects through the entire printed circuit board and is in particular free of further material of the printed circuit board. In other words, the recess is a through opening. The recess opens between the two contact tongues. In other words, the two contact tongues are arranged on opposite sides of the recess. For example, the recess is round or preferably slot-shaped in this case, and therefore has an enlarged extent in particular in one direction. For example, the cross section of the recess is rectangular or expediently pills or dione-shaped. This simplifies production, wherein the recess nevertheless has a comparatively large area, without a mechanical integrity of the printed circuit board being impaired, however.Due to the cutout, it is thus possible to check, in particular optically, from the side of the printed circuit board opposite the spring contact whether the possible component is correctly arranged between the two contact tongues, in particular the blade contact. In other words, it is thus possible, after the production / (final) mounting of the electrical circuit, to check from the side of the printed circuit board opposite the spring contact whether the spring contact is electrically contacted with the further component. Thus, it is in particular not necessary to perform the optical control from the side having the spring contact, so that flexibility in the subsequent control is increased. Due to the monitoring, a failure of the electrical circuit is unlikely, which is why reliability is increased.It is also possible, for example, to lead the possible blade contact through the recess from the side opposite the spring contact, so that it is electrically contacted with the spring contact. In other words, flexibility in the electrical contacting of the spring contact is increased, and it is necessary, for example, to guide the blade contact around the printed circuit board. Thus, design freedom is increased, and for example, an electric line length can be reduced. It is also not necessary, for example, to provide additional insulators or the like, in particular if the busbar has a comparatively high electrical potential. With the exception of the blade contact guided through the cutout, the busbar is insulated by means of the printed circuit board with respect to any electrical / electronic components arranged on the side of the spring contact. In this case, it is possible, for example, to equip the printed circuit board only on one side.For example, the two contact tongues are fastened to one another separately or, for example, via a plastic holder. Particularly preferably, however, the spring contact is a stamped bent part which is bent in a suitable manner. The two contact tongues are thus integrally formed on one another and consequently always have the same electrical potential. In this case, a number of components is reduced, production is simplified and robustness is increased. For production, in particular a corresponding contour is punched out of a spring sheet and bent suitably.For example, the electrical circuit merely has the spring contact. Particularly preferably, however, the electrical circuit comprises a plurality of such spring contacts which are connected to the printed circuit board. These are arranged, for example, on the same side of the printed circuit board or on both sides.For example, the contact tongues are fastened directly to the printed circuit board, and for example the spring contact consists only of the two contact tongues. For example, the two contact tongues are spaced apart from one another on the sides of the printed circuit board. Thus, for example, a part of the recess is not surrounded by the spring contact, and a weight is reduced. Particularly preferably, however, the contact tongues are formed on a hollow cylindrical base, by means of which the recess is surrounded. In this case, the hollow-cylindrical base, in particular its end face, expediently stands on the printed circuit board, and the axis of the hollow-cylindrical base runs in particular perpendicularly to the printed circuit board. The contact tongues are preferably connected to the base at the end opposite the printed circuit board, preferably formed on the base. On account of the base, the contact tongues are stabilized with respect to one another. On the other hand, the base guides the possible blade contact on the free end during assembly, so that, for example, the blade contact is directed in the direction of the recess and, for example, dips at least partially into the recess. Damage to the printed circuit board due to uncontrolled movement of the blade contact is thereby avoided.For example, the contact tongues or the hollow cylindrical base, if any, are soldered directly to the printed circuit board. Particularly preferably, however, the spring contact comprises two terminals which make electrical contact with the printed circuit board; preferably are soldered. This results in a defined contact surface with the printed circuit board, wherein there are no restrictions with regard to its configuration due to other requirements. In particular, the terminals are arranged substantially parallel to the printed circuit board, so that a full-surface contact of the latter with the printed circuit board is realized, for which reason the spring contact is held comparatively stably on the printed circuit board. This also allows a comparatively low-ohmic electrical connection between the spring contact and the printed circuit board. Expediently, the spring contact is a surface-mountable component (SMD), and the connections are in particular correspondingly designed in this case. Preferably, the connections are arranged on opposite sides of the recess. Tilting of the spring contact is thus at least partially avoided by means of the connections, for which reason robustness is increased. In an alternative, the spring contact is provided for plug-through mounting.For example, the spring contact is only placed on the surface of the printed circuit board. Particularly preferably, however, the spring contact comprises a pin which is inserted into a receptacle of the printed circuit board. In particular, the course of the pin is substantially perpendicular to the plane of extension of the printed circuit board. The receptacle is, for example, a bore or expediently designed in the manner of a blind hole. Tilting of the complete spring contact with respect to the printed circuit board is thus avoided by means of the pin, in particular during assembly or also during operation of the electrical circuit. The pin and the receptacle also define the desired position of the spring contact on the printed circuit board, which simplifies assembly. Expediently, a press fit or preferably a clearance fit is formed between the pin and the receptacle, wherein the pin bears in particular against a wall of the receptacle. Preferably, the pin serves substantially only for stabilization / positioning. At least, there is no (additional) electrical contacting of the pin. Alternatively, the pin is passed through the complete printed circuit board, for example, and soldered to the printed circuit board on the side opposite the contact tongues. For example, only a single such pin is present. However, it is particularly preferred that two such pins are present, which are in particular spaced apart from one another. Because of the two pins, stability is further increased. Also, by means of these, the position of the spring contact is predetermined comparatively accurately.For example, the recess is spaced apart from the receptacle. Particularly preferably, however, the recess opens into the receptacle, so that the receptacle is open laterally. Thus, it is possible to form the receptacle and the recess in one operation, and therefore a manufacturing time is reduced. Tolerance compensation is also provided due to the recess, which is why reliable assembly is made possible even with high manufacturing tolerances.For example, the electrical circuit is arranged without a housing or, for example, in a housing of a component of the motor vehicle having the electrical circuit, such as, for example, a motor housing of the possible electric motor. This is thus in particular an integrated electronic system. Particularly preferably, the electrical circuit comprises a housing, within which the printed circuit board is arranged. The housing is preferably made of a plastic. In this case, the housing has an opening, wherein the opening is in particular formed in such a way that the printed circuit board can be inserted through the latter into the housing. Expediently, the area of the opening is equal to or greater than the area of the printed circuit board, which simplifies assembly. In the assembled state, the opening is closed in particular by means of a cover which is fastened, for example, detachably or non-detachably, to the housing. For example, the spring contact is arranged on the side of the printed circuit board facing the opening. In particular, the printed circuit board is first mounted in the housing and then the possible blade contact is inserted into the housing via the opening and introduced between the contact tongues. Alternatively, the spring contact is arranged on the side of the printed circuit board opposite the opening. In particular, the blade contact is already located in the housing when the printed circuit board is inserted into the housing. Preferably, the blade contact is fastened to an inner wall of the housing, and for example the housing is injection-molded onto the blade contact, so that a substantially non-detachable connection is established between them. A comparatively robust electrical circuit is thus provided. Since the cutout is present, it is possible to check whether the possible blade contact is arranged between the two spring contacts, that is to say whether a corresponding electrical contact has been made.For example, the blade contact is not a component of the electrical circuit. Particularly preferably, however, the electrical circuit comprises the blade contact, which is designed in the manner of a blade or the like. The blade contact is in particular a component of a busbar and preferably provided by means of a stamped grid. For example, the blade contact is welded to the contact tongues for mounting. Particularly preferably, however, the blade contact is held there merely in a force-fitting manner. This allows easy assembly and also disassembly.For example, the blade contact is inserted between the contact tongues in such a way that it only remains on one side of the printed circuit board. Particularly preferably, however, the blade contact is guided through the cutout. This is thus also stabilized by means of the printed circuit board, which increases robustness. Here, for example, the free end of the blade contact is located on the side of the printed circuit board on which the contact tongues are also located. Thus, for assembly, the free end of the blade contact is first guided into the recess from the side of the printed circuit board facing away from the spring contact and subsequently further until the blade contact is held between the contact tongues in a force-fit manner. Particularly preferably, however, the free end of the blade contact is located on the side of the printed circuit board facing away from the spring contact. Thus, for assembly, the blade contact is first inserted between the contact tongues and then introduced further until it dips into the recess. The blade contact is thus steered and any (slight) offset is compensated for, so that a secure contacting takes place. Particularly preferably, the blade contact is thus guided into the recess by means of the spring contact, in particular by means of the possible hollow cylindrical base. In other words, this preferably serves for guiding and aligning the blade contact, which facilitates assembly.In particular, in the assembled state, the blade contact protrudes through the printed circuit board. In this case, the printed circuit board is suitably equipped essentially only on one side, so that in the assembled state only the protrusion of the blade contact is located on the side of the printed circuit board facing away from the spring contact. This allows a comparatively simple identification as to whether the electrical contacting between the contact and the blade contact has taken place. In summary, checking the correct assembly of the electrical circuit is thus simplified.For example, the free end of the blade contact is not treated any further. Thus, manufacturing cost is reduced. Particularly preferably, however, the free end of the blade contact, i.e. in particular that end of the blade contact which is guided through the printed circuit board, is colored. The colour used here is preferably an electrically non-conductive colour, in particular a signal colour and / or a fluorescent colour. Due to the coloring, an optical contrast to the printed circuit board is increased. The identification of the free end is thus facilitated, in particular provided that the position of the free end is detected automatically. Preferably, the color is adapted to any illumination that may be present when checking the position of the free end.The invention further relates to an auxiliary unit of a motor vehicle, which has an electrical circuit of this type. The motor vehicle is land-bound, for example, and is, for example, a truck (truck), bus or preferably a passenger car (passenger car). The auxiliary unit here does not serve directly for the propulsion of the motor vehicle and is in particular an electromotive adjusting drive. Expediently, the auxiliary unit is an electric door lock, an electric motor window lifter, an electric motor door adjustment, a cooling fan, an air conditioning compressor, a pump or a transmission actuator. The auxiliary unit serves in particular to provide a functionality, wherein energization is required for providing the functionality. For controlling / regulating the functionality, the auxiliary unit has the electrical circuit. The electrical circuit preferably serves for the operation of an electric motor of the auxiliary unit. Particularly preferably, however, the auxiliary unit is an electric lock which thus has the electric motor by means of which a pawl is driven. This can be brought into engagement with a further component of the motor vehicle, namely in particular by the electric motor being operated. It is also possible to release the engagement by means of opposite operation of the electric motor.The method serves for producing an electrical circuit of a motor vehicle, which comprises a printed circuit board on which a spring contact is arranged, which has two contact tongues extending away from the printed circuit board. The contact tongues are elastically bendable with respect to each other. The printed circuit board has a cutout which opens out between the two contact tongues. In this case, a blade contact is held between the contact tongues in a force-fitting manner.In the method, in a first working step, the printed circuit board with the spring contact already arranged therein is provided. The printed circuit board in particular already has the cutout, and the spring contact is expediently soldered to the printed circuit board. Advantageously, further electrical and / or electronic components are fastened to the printed circuit board.In a subsequent working step, the blade contact is inserted between the contact tongues from the end of the contact tongues facing away from the printed circuit board. In this case, for example, the free end of the blade contact is first inserted between the contact tongues and moved further in the direction of the printed circuit board. For example, the free end is guided through the cutout or remains on the side of the printed circuit board on which the spring contact is also arranged. Preferably, the housing is present here, and the blade contact is located in particular on the side of the housing facing away from the opening. For inserting the blade contact between the contact tongues, the printed circuit board is inserted in particular into the housing.In a subsequent working step, it is checked from the side of the printed circuit board opposite the spring contact whether the blade contact is located between the contact tongues. For example, this is done through the recess, for example, the check is done by radar or mechanically. In this case, for example, a test pin or the like is inserted through the cutout. Particularly preferably, the checking takes place optically. For this purpose, an image is expediently produced by means of a camera, and this is correspondingly evaluated. Thus, a contactless checking of the arrangement of the blade contact and thus of the electrical contacting between the blade contact and the spring contact takes place, wherein in particular no current is supplied to the electrical circuit. Thus, checking is enabled in a comparatively short period of time. The subsequent checking is also possible, wherein before the completion of the assembly, in particular the attachment of the possible cover to the housing, the photograph is produced, which is evaluated downstream. A process speed for producing corresponding electrical circuits is thus increased, and damage to the electrical circuit during the checking is substantially ruled out.The developments and advantages explained in connection with the electrical circuit are to be transferred analogously also to the method / the auxiliary unit and to one another and vice versa.An exemplary embodiment of the invention is explained in more detail below with reference to a drawing. Shown therein are: FIG. 1 is a schematic side view of a motor vehicle with an electrical circuit, FIG. 2 shows a perspective view of a section of a printed circuit board of the electrical circuit, wherein a plurality of spring contacts are arranged on the printed circuit board,FIGS. 3, 4 show one of the spring contacts from different perspectives, FIG. 5 is a plan view of the spring contact, FIG. 6 is a plan view of a portion of the printed circuit board, FIG. 7 shows a sectional illustration of the electrical circuit, and FIG. 8 shows a method for producing the electrical circuitCorresponding parts are provided with the same reference numerals in all figures.FIG. 1 schematically shows a motor vehicle 2 in the form of a passenger car (passenger car). The motor vehicle 2 has a plurality of wheels 4, by means of which contact is made with a roadway, not shown in more detail. At least some of the wheels 4 are driven by means of a main drive, not shown, by means of which the motor vehicle can thus be moved. The motor vehicle 2 further has an auxiliary unit 6, which does not serve directly for the propulsion of the motor vehicle 2. The auxiliary unit 6 is an electromotive adjusting drive, and in the example shown an electric lock, which is also referred to as an electric door lock. Here, the auxiliary unit 6 is a component of a door of the motor vehicle, not shown in detail, and has an electric motor, by means of which a pawl or the like is / can be driven. In this case, it is possible to bring the latch into engagement with a further component of the motor vehicle 2 by means of appropriate energization of the electric motor, wherein an adjustment of the door with respect to a body of the motor vehicle 2 is made possible or prevented as a function of the engagement. The auxiliary unit 6 has an electrical circuit 8, by means of which the operation of the electric motor takes place.FIG. 2 shows a perspective view of a portion of the electrical circuit 8. The electrical circuit 8 has a substantially planar printed circuit board 10, on which a plurality of spring contacts 12 are arranged. The circuit board 10 is a rigid circuit board and has a plurality of conductive paths, not shown in detail, made of copper, which are fastened to a surface of a body of the circuit board 10. The body is made of a glass fiber reinforced epoxy resin, and the circuit board 10 is thus rigid. The spring contacts 12 are soldered to the circuit board 10 and are therefore electrically contacted to at least some of the conductor tracks.The spring contacts 12 are structurally identical to one another, and one of these is shown from different perspectives in FIGS. 3 and 4 and in a plan view in FIG. 5. Each spring contact 12 is a stamped and bent part and is integral. In other words, the spring contact 12 is stamped from a metal sheet, namely a spring sheet or copper sheet, and is bent accordingly.The spring contact 12 has a hollow cylindrical base 14, the cross section of which is substantially rectangular, and the axis of which is arranged substantially perpendicular to the printed circuit board 10 in the assembled state. The base 14 is made of a metal band bent into the rectangular shape. The metal strip has a mushroom-shaped end 16 and a fork-shaped end 18, which are inserted into one another, so that the base 14 is fully closed. Due to such a configuration, no further mounting means are required for creating the spring contact 12.On one of the end faces of the base 14, a contact tongue 20 is formed on each of two of the opposite sides 2, which contact tongues are designed mirror-symmetrically to one another. The contact tongues 20 extend away from the printed circuit board 10 in the assembled state and are hook-shaped. In this case, these contact one another in the region of the free ends. The free ends themselves are bent over and spaced apart from one another, so that an opening 22 is formed between the contact tongues 20. Two connections 24 are formed on the end face of the base 14 opposite the contact studs 20, these being assigned to the same sides of the base 14 as the contact studs 20. The connections 24 extend parallel to the printed circuit board 10 in the assembled state. A pin 26 is formed on each of the remaining two sides of the end face of the base 14, which pin is perpendicular to the printed circuit board 10 and thus parallel to the course of the hollow cylindrical base 14. The pins 26 thus extend away from the base 14 and are located on the side of the base 24 opposite the contact studs 20.FIG. 6 shows a plan view of a portion of the printed circuit board 10 in the region in which the spring contact 12 is mounted. The printed circuit board 10 has two connection pads 28, which are substantially rectangular and which are electrically contacted by at least one of the conductor tracks, which are not shown in more detail. Between the two connection pads 28 there is a substantially rectangular cutout 30, which extends through the entire printed circuit board 10 and which is spaced apart from the connection pads 28. The cutout 30 and the connection pad 28 are arranged parallel to one another, such that the connection pad 28 are assigned to two opposite sides of the cutout 30. At the remaining sides of the recess 30, a receptacle 32 opens out in each case, which likewise protrudes through the entire printed circuit board, and the cross section of which is round or at least semicircular. In summary, the recess 30 opens into the receptacles 32.FIG. 7 shows a sectional illustration perpendicular to the printed circuit board 10 of the spring contacts 12 fastened to the printed circuit board 10 in the mounted state, the printed circuit board 10 being shown shortened. The circuit board 10 is arranged within a substantially pot-shaped or box-shaped housing 34 of the electrical circuit 8, which is made of a plastic. The housing 34 has an opening 36 which, in the assembled state, is closed by means of a cover 38 made of a plastic. Here, the lid 38 is fixed to the housing 34, so that the housing 34 is closed. A busbar 40 is introduced into the base of the pot-shaped housing 34, that is to say into the side of the housing 34 opposite the opening 36, said busbar being encapsulated by injection molding by means of the plastic forming the housing 34. Thus, the bus bar 40 is non-detachably connected to the housing 34. The busbar 40 has a substantially sword-shaped blade contact 42 which projects into the interior of the housing 34.Each pin 26 of the spring contact 12 is inserted in each case into one of the receptacles 32, by means of which an alignment of the spring contact 12 with respect to the printed circuit board 10 is aligned. As a result, one of the terminals 24 is in each case located on one of the terminal pads 28, and the cutout 30 is surrounded by means of the base 14. Thus, the contact tongues 20 are integrally formed on the hollow cylindrical base 14, by means of which the recess 30 is surrounded. In summary, the spring contact 12 thus has the two contact tongues 20 which extend away from the printed circuit board 10 and which can be elastically bent with respect to one another. In this case, printed circuit board 10 has the cutout 30, which opens out between the two contact tongues 20. The pads 28 are soldered to the circuit board 10 and so that the spring contact 12 is fixed to the circuit board 10. In this case, a further stabilization takes place on account of the pins 26 inserted into the receptacles 32.The printed circuit board 10 is oriented in such a way that the spring contact 12 is located on the side of the printed circuit board 10 facing away from the opening 36. Thus, the spring contact 12 is disposed on the side of the circuit board 10 opposite the opening 36. The blade contact 42 is arranged perpendicular to the printed circuit board 10 and is located between the two contact tongues 20, so that these are spread apart by means of the blade contact 42. Due to the elastic configuration, these bear in a force-fitting manner against the blade contact 42 and the blade contact 42 is held in a force-fitting manner between the two contact tongues 20.The blade contact 42 is guided through the cutout 30, such that the blade contact 42 projects through the printed circuit board 10. Applied to the free end of the blade contact 42 guided through the printed circuit board 10 is a color layer 44, which has a signal color. In other words, the free end of the blade contact 42 is colored.FIG. 8 shows a method 46 for producing the electrical circuit 8. In a first working step 48, the printed circuit board 10 with the spring contacts 12 arranged thereon is provided. In addition, further electrical and / or electronic components are fastened to the printed circuit board 10. Also, the housing 34 is provided with the bus bar 40 fixed thereto.In a subsequent second working step 50, the printed circuit board 10 is introduced into the housing 34 through the opening 36. The opening 22 is oriented toward the free end of the blade contact 42 which dips into the opening 22 when the printed circuit board 10 is inserted further and spreads the two contact tongues 20. In summary, the blade contact 42 is thus inserted between the contact tongues 20 from the end of the contact tongues facing away from the printed circuit board 10. The circuit board 10 is moved further into the housing 34, namely in the direction of the bottom of the housing 34, wherein the blade contact 42 slides further in the direction of the circuit board 10 and dips into the base 14. If there should be a slight offset due to manufacturing tolerances or the like, since the blade contact 42 is designed to be bent on the free end side, it is correspondingly aligned by means of the comparatively robust base 42 without damage to the printed circuit board 10. When the printed circuit board 10 is moved further, the free end of the blade contact 42 dips into the cutout 30 and is passed through the complete printed circuit board 10. Subsequently, the printed circuit board 10 is stabilized in the housing 34 by means of clips or the like, not shown in more detail.In a subsequent third step 52, an image, namely a photograph, of the interior of the housing 34 is produced through the opening 36, which shows the side of the printed circuit board 10 facing the opening 76. If the blade contact 42 is held in the desired manner by the spring contact 12, the free end of the blade contact 42 is located on the side of the printed circuit board 10 facing the opening 36. If the ink layer 44 is thus recognizable on the image, it is ensured that the blade contact 42 is passed through the recess 30. This is only possible if it is also located between the contact tongues 20. Thus, when the ink layer 44 is not visible on the image, the blade contact 42 is not passed through the recess 30, and the electric circuit 8 is faulty.In summary, it is thus checked in the third working step 52 from the side of the printed circuit board 10 opposite the spring contact 12 whether the blade contact 42 is located between the contact tongues 20. If this is the case, the cover 38 is then fastened to the housing 34 and the latter is closed.The invention is not limited to the embodiment described above. Rather, other variants of the invention can also be derived from this by the person skilled in the art without departing from the subject matter of the invention. In particular, all the individual features described in connection with the exemplary embodiment can also be combined with one another in another manner without departing from the subject matter of the invention.List of reference characters2 Motor vehicle 4 Wheel 6 Auxiliary unit 8 Electrical circuit 10 Printed circuit board 12 Spring contact 14 Base 16 Mushroom-shaped end 18 Fork-shaped end 20 Contact tongue 22 Opening 24 Connection 26 Pin 28 Connection pad 30 Cutout 32 Receptacle 34 Housing 36 Opening 38 Cover 40 Busbar 42 Blade contact 44 Color layer 46 Method 48 First working step 50 Second working step 52 Third working step

Claims

Electrical circuit (8) of a motor vehicle (2), having a printed circuit board (10) on which a spring contact (12) is arranged, which has two contact tongues (20) which extend away from the printed circuit board (10) and which can be elastically bent with respect to one another, wherein the printed circuit board (10) has a cutout (30) which opens out between the two contact tongues (20).Electrical circuit (8) according to Claim 1, characterized in that the contact tongues (20) are integrally formed on a hollow-cylindrical base (14), by means of which the cutout (30) is surrounded.Electrical circuit (8) according to Claim 1 or 2, characterized in that the spring contact (12) has two connections (24) which are arranged on opposite sides of the cutout (30) and are soldered to the printed circuit board (10).Electrical circuit (8) according to one of Claims 1 to 3, characterized in that the spring contact (12) has a pin (26) which is plugged into a receptacle (32) of the printed circuit board (10).Electrical circuit (8) according to Claim 4, characterized in that the cutout (30) opens out into the receptacle (32).Electrical circuit (8) according to one of Claims 1 to 5, characterized bya housing (34) which has an opening (36) and in which the printed circuit board (10) is arranged, the spring contact (12) being arranged on that side of the printed circuit board (10) which is opposite the opening (36).Electrical circuit (8) according to one of Claims 1 to 6, characterized in that a blade contact (42) is held between the contact tongues (20) in a force-fitting manner.Electrical circuit (8) according to Claim 7, characterized in that the blade contact (42) is guided through the cutout (30).Electrical circuit (8) according to Claim 7 or 8, characterized in that a free end of the blade contact (42) is colored.Method (46) for producing an electrical circuit (8) according to one of Claims 7 to 9, in which - the printed circuit board (10) is provided with the spring contact (12) arranged thereon, - the blade contact (42) is inserted between the contact tongues (20) from the end of the contact tongues (20) facing away from the printed circuit board (10), and - it is checked from the side of the printed circuit board (10) opposite the spring contact (12) whether the blade contact (42) is located between the contact tongues (20).

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