EP3496126B1 - Power relais for a vehicle - Google Patents

Description

The invention relates to a power relay according to the preamble of claim 1, for a vehicle, in particular a commercial vehicle. Such a power relay is out JP 2006 170076 A known.

Generic power relays are used in vehicle technology, especially in commercial vehicles. On the one hand, the power relays are used to electrically separate the vehicle battery from the vehicle electrical system. On the other hand, such relays are used to switch electrical motors of actuating devices (e.g. hydraulic pump or lifting platform). At low voltages of typically 12 to 24 volts, such a power relay must be able to switch currents up to a current of approximately 300 amperes and must be of a correspondingly massive construction. Usual relays used for this purpose usually consist of a pot-shaped body made of metal (e.g. iron or steel), in which a magnet coil, a magnet yoke and a magnet armature connected to a contact bridge (double contact) are accommodated.

To connect the power relay to a load circuit to be switched in the vehicle, the power relay usually comprises massive connecting bolts (threaded bolts) made of metal, which typically have a diameter of 0.5 to 1 cm. As intended, cable lugs of the connecting cables of the load circuit to be switched are fixed in contact with these connecting bolts using screw nuts (contact nuts).

Power relays are still in particular off DE 10 2010 018 755 A1 , DE 10 2010 018 738 A1 , DE 44 18 740 A1 , DE 43 06 456 A1 , US 2003 0214766 A1 and JP 2005 38705 A known.

Out DE 85 31 352 U1 an arc quenching chamber with an overpressure safety device is known which has a gas discharge opening in the event of a critical overpressure releases. The overpressure protection is formed by predetermined breaking points in the form of blow shutters, which are each connected to a housing of the arc quenching chamber via a film hinge and burst open in the event of a critical overpressure.

Unfortunately, the conventional power relays are comparatively heavy and complex to manufacture. Another problem with the power relays used conventionally is that a wide variety of different designs are currently used, which differ due to different spacing of the connecting bolts and different mounting options for the relay housing (e.g. on the side of the housing pot, over the connection side or over the bottom of the relay housing opposite to this) differentiate.

In order to be able to serve the market comprehensively, in particular in order to maintain existing commercial vehicles with different electrical system configurations and, if necessary, to be able to retrofit them with new power relays, a large number of different designs of the power relay must be kept available, which leads to considerable manufacturing and storage costs.

The invention has for its object to provide a particularly efficient and easy to build power relay for a vehicle, especially a commercial vehicle.

This object is achieved according to the invention by the features of claim 1. The power relay according to the invention comprises a housing which is formed from a connection base and a housing pot placed thereon. Two connection bolts are inserted into the connection base, via which the power relay can be contacted with connection lines of an external load circuit to be connected. The power relay further comprises a coil assembly arranged in the housing with a magnet coil and a corresponding magnet armature. The magnet armature is in this case coupled to a contact bridge via a force transmission element and can be displaced in the housing under the action of a magnetic field generated by the magnet coil such that the contact bridge can be moved reversibly between a closed position and an open position is. The closed position is characterized in that the contact bridge bridges the connecting bolts in an electrically conductive manner, as a result of which the power relay is switched on. The open position, on the other hand, is characterized in that the contact bridge is decontacted from the connection bolts, so that there is no conductive connection between the connection bolts and the power relay is therefore switched off.

According to the invention, the housing pot is designed as a plastic injection molded part. This enables, compared to conventional power relays provided with a metal housing pot, a substantial reduction in the manufacturing and material expenditure as well as a decisive weight saving. The connection base is also preferably a plastic injection molding component.

The power relay according to the invention can either be a bistable relay which permanently maintains both the closed position and the open position when the solenoid is not energized, or it can be a monostable relay. In the latter case, the power relay can be designed as a make or break contact, with the relay automatically taking the open position in the first-mentioned design, and the closed position in the latter design, when the solenoid is not energized. Both bistable and monostable designs of the power relay are preferably implemented according to the construction principle according to the invention.

In a preferred embodiment, the coil assembly further comprises a magnetic yoke. In order to achieve high stability of the housing despite the low weight and despite the compact construction, the magnetic yoke expediently comprises a torsionally stable structure which is accommodated in the housing pot in a rotationally fixed manner over the entire axial height. The axial height here is the extent of the housing pot along the housing pot axis perpendicular to the bottom of the housing pot. In an expedient embodiment, the torsionally stable structure of the magnetic yoke is formed by a one-piece, U-shaped angled bracket, the legs of which the magnet coil parallel to its coil axis reach around. In order to be able to accommodate the torsionally stable structure of the magnetic yoke, in particular the bracket, in a rotationally fixed manner, the housing pot preferably has an at least approximately rectangular cross section at least in its interior, the magnetic yoke, in particular the bracket, extending parallel to two of the four side walls in the manner of a cross member and is supported on both sides on the two remaining side walls.

Due to the non-rotatable mounting of the magnetic yoke, the housing pot introduces a torque acting on it, which is caused, for example, by tightening the contact nuts, into the torsionally stable magnetic yoke. If the housing pot is twisted, the magnetic yoke, in particular the bracket, must always be twisted, which in turn relieves the pressure on the housing pot. This counteracts material fatigue or even breakage of the housing pot.

In order to further improve the torsional stability of the housing, the connection base is preferably also coupled non-rotatably to the magnetic yoke, for example by the positive engagement of the magnetic yoke with molded projections in corresponding recesses in the connection base. In this way, any torques exerted on the connection base are not only transmitted indirectly to the magnetic yoke via the housing pot. Rather, at least some of these torques are introduced directly from the connection base into the magnetic yoke, which in turn relieves the pressure on the housing pot, and in particular the connection between the housing pot and the connection base.

In principle, the power relay in the context of the invention can be a purely electromechanical component in which the solenoid coil is activated (energized) and deactivated (de-energized) exclusively on the basis of external control signals. However, the power relay preferably additionally comprises control electronics accommodated in the housing for controlling the magnetic coil. The control electronics set external control signals (which in this case, for example, are also emitted as pulse signals, in particular in digital form ) in a corresponding control current for the solenoid. Optionally, the control electronics also include other functions, such as current or voltage measurement between the connection bolts and / or protective functions, which force the power relay to be switched off in the event of overvoltage and / or undervoltage, overload or - in the case of multi-pole versions of the power relay - a fault current or an asymmetrical current distribution cause.

In purely electromechanical designs as well as in electronic designs, the power relay comprises a number of signal connections, each of which can be connected to an external signal line. The signal connections are expediently fixed in the connection base, just like the connection bolts for the load current.

The signal connections are used to supply at least one electrical control signal to the power relay and / or to output at least one electrical status signal through the power relay. Optionally, at least one of the signal connections is also provided for supplying an electrical supply voltage or an electrical reference potential, in particular ground. In a purely electromechanical design of the power relay, the signal connections are directly contacted with the solenoid. In the case of electronic designs of the power relay, at least some of the signal connections, on the other hand, are regularly connected to the control electronics. This control electronics provides additional functions (e.g. measuring functions, protective functions, bus communication, etc.). In the latter case, the signals supplied via the signal connections generally serve only indirectly to control the magnetic coil.

Generic power relays are regularly used in harsh operating environments in which these relays are exposed to water, oil, as well as dust and other soiling. The housing of such power relays must therefore generally be dust and liquid-tight (in particular according to protection class IP6K7 or IP6K9K). In order to connect the housing pot with To guarantee the required tightness of the connection base, the connection base is preferably connected to the housing pot in a fluid-tight manner by means of a hardening casting compound, for example an epoxy resin. In order to enable a simple and durable potting of this connection point, in an advantageous embodiment the housing pot has a circumferential shoulder on the opening side, on which the connection base rests with a circumferential radial web. The housing pot engages on the outside with a collar around the radial web of the connection base, the collar projecting axially beyond the radial web. The collar of the housing pot thus surrounds the radial web molded onto the connection base in the manner of a balustrade. Thus, a trough-like receptacle (hereinafter referred to as "trough") is formed for the potting compound by the collar and the connection base. In the assembled state of the power relay, this tub is completely or at least partially filled with the sealing compound.

Each of the signal connections described above is in each case connected to the magnet coil or the control electronics connected upstream thereof via an associated connecting conductor (which is preferably formed by a bent sheet metal stamped part). Each of the connection conductors is preferably routed through the connection base in the region of the trough. Thus, when the housing is cast, each of the connection conductors is also embedded in the casting compound, as a result of which the connection conductors are also sealed by the connection base, without the need for special measures.

In order to further stabilize the connection between the housing pot and the connection base, the collar of the housing pot is provided with at least one radial contour in the region of the trough. The or each radial contour of the collar can be formed by a radial recess (which reduces the material thickness of the collar) or a radial projection (which increases the material thickness of the collar). Corresponding to the or each radial contour, at least one counter contour is formed on the connection base in the region of the trough. The radial contour and the corresponding counter-contour form a positive connection with the casting compound, through which the connection base and the housing pot are locked to one another in the circumferential direction, ie tangentially to the axis of the magnetic coil and the housing pot. As a result of this locking, rotation of the connection base relative to the housing pot is also effectively blocked by the potting compound. The radial contour and the corresponding counter-contour preferably also have undercuts, on the basis of which the housing pot and the connection base are also locked to one another in the radial direction by forming the potting compound with the radial contour and the counter-contour. In this way, a radial bulging of the housing pot, due to which the collar of the housing pot would detach itself at least locally from the radial web of the connection base, is prevented by the potting compound. In a preferred embodiment variant, the radial contour is designed as a latching lug which engages over the radial web and thus latches onto the housing pot.

As is known, when a generic relay is switched, especially in the event of a short circuit, there is regularly a high gas pressure in the interior of the housing, which under unfavorable circumstances could lead to an explosion or at least to an uncontrolled bursting of the relay housing. The cause of the high gas pressure can be the expansion of the air in the interior of the housing due to heating and / or the evaporation of residual moisture in the air taken up in the interior of the housing. The cause of the air heating can in turn be a switching arc or the heating of the live parts due to the current flow (in particular a short-circuit current). The explosion or the uncontrolled bursting of the housing can lead to dangerous situations, in particular a short circuit of live parts with ground and an associated fire hazard or personal risk and must therefore be excluded. In order to ensure this safety requirement with a power relay that is as compact and lightweight as possible, in an advantageous embodiment of the power relay in the housing - and preferably in the housing pot - an overpressure safety device is provided which, in the event of a critical overpressure in the housing, releases a gas discharge opening and thus a controlled one Ensures pressure equalization with the environment.

The overpressure safety device is integrated in one piece in the housing (and here in particular in the housing pot), in particular molded onto the housing. In this embodiment, the overpressure protection is formed by a predetermined breaking point, which bursts in the event of overpressure and thus releases the gas discharge opening to relieve the other housing areas. The predetermined breaking point preferably has a curved, for example U-shaped, V-shaped, or trapezoidal shape, and thus surrounds from three sides a tab-like section (hereinafter "tab"), which forms the closure of the overpressure safety device. The fourth side of this tab is expediently designed as a film joint along a connecting line running between the ends of the predetermined breaking point. The flap framed by the predetermined breaking point forms a gas discharge opening with a defined shape and size. The film joint connecting the predetermined breaking point enables the tab to be bent out of the housing wall in a defined manner when the predetermined breaking point bursts open, but prevents the tab from tearing off in an uncontrolled manner, thereby counteracting a possible risk to persons or damage to adjacent parts. In a particularly advantageous embodiment variant, the predetermined breaking point has, in particular, a keyhole shape, that is to say it is U-shaped with a circularly prepared base.

Since the housing of the power relay is no longer leakproof after the predetermined breaking point has burst open, the power relay must be replaced regularly in this case. In order to rule out that the power relay is still operated, the power relay is provided with a safety function in an expedient development, which generates a warning signal after the predetermined breaking point has failed and / or forcibly switches the power relay into a safe state. In one embodiment of the power relay, the safety function comprises a forced shutdown, by means of which the power relay is switched off permanently by decontacting the contact bridge from the connecting bolts and is therefore irreversibly decommissioned. For certain embodiments, the fuse function of the power relay - in adaptation to the respective application - can also switch on the power relay include. For example, a power relay used as a battery switch in a commercial vehicle must also remain switched on in the event of a fault, since otherwise the electrical supply to the vehicle electrical system would collapse - possibly while driving.

The forced shutdown is triggered immediately by the bursting of the predetermined breaking point. For this purpose, an electrical safety line is mechanically coupled to the predetermined breaking point in such a way that the securing line is cut in the event of failure of the predetermined breaking point. The fuse cable is in direct or indirect connection with the solenoid coil, so that cutting it causes the power relay to be switched off. The fuse line can be part of the power supply of the solenoid coil or part of a signal circuit connected to the control electronics, if present. In principle, it is also conceivable within the scope of the invention that the safety line is electrically switched through in the event of a failure of the predetermined breaking point, in which case the switching through (i.e. the establishment of a conductive connection via the safety line) triggers the forced shutdown, or that the state of the predetermined breaking point results from another sensor is checked.

Fig. 1

in perspektivischer Ansicht von schräg oben ein Leistungsrelais für einen Lastkraftwagen,

Fig. 2

in perspektivischer Ansicht von schräg unten das Leistungsrelais,

Fig. 3

in einer Explosionsdarstellung vier Teilbaugruppen des Leistungsrelais, nämlich einen Anschlusssockel, einen Gehäusetopf, eine Spulenbaugruppe sowie eine eine Steuerelektronik tragende Platine,

Fig. 4

in perspektivischer Ansicht von schräg oben die Spulenbaugruppe des Leistungsrelais,

Fig. 5

in perspektivischer Ansicht von schräg unten die Spulenbaugruppe gemäß Fig. 4,

Fig. 6

in perspektivischer Ansicht von schräg oben isoliert einen Magnetkreis des Leistungsrelais mit einem Magnetjoch und einem Magnetanker sowie mit einer Koppelstange, über die der Magnetanker auf eine (hier nicht dargestellte) Kontaktbrücke wirkt,

Fig. 7

in perspektivischer Ansicht von schräg oben einen Trägerkörper der Spulenbaugruppe,

Fig. 8

in perspektivischer Ansicht von schräg unten den Trägerkörper gemäß Fig. 7,

Fig. 9

in einem Querschnitt IX-IX gemäß Fig. 7 den dortigen Trägerkörper,

Fig. 10

in perspektivischer Ansicht von oben das Leistungsrelais in einem unvergossenen Vormontagezustand,

Fig. 11

in einem vergrößert dargestellten Ausschnitt XI aus Fig. 10 ein Detail des Gehäuses des Leistungsrelais,

Fig. 12

in einem Längsschnitt Xll-Xll gemäß Fig. 1 und 2 das dortige Leistungsrelais,

Fig. 13

in einem Längsschnitt XIII-XIII gemäß Fig. 1 und 2 das dortige Leistungsrelais,

Fig. 14

in einem Querschnitt XIV-XIV gemäß Fig. 1 und 2 das dortige Leistungsrelais, und

Fig. 15

in perspektivischer Ansicht von schräg oben den Gehäusetopf des Leistungsrelais.

Exemplary embodiments of the invention are explained in more detail below with reference to a drawing. In it show:

Fig. 1

a perspective view from obliquely above a power relay for a truck,

Fig. 2

the perspective view of the power relay obliquely from below,

Fig. 3

in an exploded view four sub-assemblies of the power relay, namely a connection base, a housing pot, a coil assembly and a circuit board carrying control electronics,

Fig. 4

in a perspective view obliquely from above, the coil assembly of the power relay,

Fig. 5

in a perspective view obliquely from below the coil assembly Fig. 4 ,

Fig. 6

a perspective view from obliquely above isolated a magnetic circuit of the power relay with a magnetic yoke and a magnetic armature and with a coupling rod, via which the magnetic armature acts on a contact bridge (not shown here),

Fig. 7

a perspective view from obliquely above a carrier body of the coil assembly,

Fig. 8

in a perspective view obliquely from below the carrier body Fig. 7 ,

Fig. 9

in a cross section IX-IX according to Fig. 7 the support body there,

Fig. 10

a perspective view from above of the power relay in a non-potted pre-assembly state,

Fig. 11

in an enlarged section XI Fig. 10 a detail of the housing of the power relay,

Fig. 12

in a longitudinal section Xll-Xll according Fig. 1 and 2nd the power relay there,

Fig. 13

in a longitudinal section XIII-XIII according to Fig. 1 and 2nd the power relay there,

Fig. 14

in a cross section according to XIV-XIV Fig. 1 and 2nd the power relay there, and

Fig. 15

in a perspective view obliquely from above the housing pot of the power relay.

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

That in the Fig. 1 and 2nd Power relay 1 shown as a whole comprises a housing 2 which is formed from two parts, namely a connection base 3 and a housing pot 4. Both the connection base 3 and the housing pot 4 are formed here as injection molded components made of plastic.

The connection base 3 delimits the housing 2 towards a connection side on which the power relay 1 can be contacted with an external load circuit and with external control lines. This connection side is - independent from the actual orientation of the power relay 1 in the surrounding space - also referred to as the top 5. The housing pot 4 encloses with four side walls 6 and a housing base 7 the remaining sides of an approximately cuboid housing interior 8 ( 12 to 14 ). The housing base 7 closes the housing 2 to an underside 9 facing away from the upper side 5 (the term “underside” also being used regardless of the actual orientation of the power relay 1 in the surrounding space).

To connect two connecting lines of the load circuit to be connected, two solid connecting bolts 10 are fixed in the connecting base 3, each of which protrudes outwards from the housing 2 with a threaded shaft 11. The connecting bolt 10 is a massive turned part made of metal, which for example has a diameter of 0.8 cm in the area of the threaded shaft 11. To connect the respective connecting line of the load circuit, an end cable lug of this connecting line is placed on the assigned threaded shaft 11 and screw-contacted by means of a screw nut (contact nut). Alternatively, the connection bolts 10 can also be formed by sleeves, each with a threaded bore. In this case, instead of contact nuts, contact screws are provided for contacting the connecting cables, which are screwed into the threaded holes. How in particular from Fig. 13 emerges, the connection bolts 10 are fixed in the connection base 3 by extrusion coating with the plastic material of the connection base 11.

In order to rule out an electrical flashover or other short circuit between the connection bolts 10 and the connection lines of the load circuit, which may be attached to them, a partition 12 is formed on the outside of the connection base 3 and protrudes into the space formed between the connection bolts 10.

To control the power relay 1, that is, to trigger switching processes by which the power relay 1 is switched on by establishing an internal electrically conductive connection between the connecting bolts 10 or - is switched off by separating this electrically conductive connection, several (in this example three) signal connections 13 are also formed on the connection base 3, via which three corresponding external control lines can be screw-connected to the power relay 1 with an end-side cable lug. Each signal connection 13 is electrically connected to the housing interior 8 via a connection conductor 14 in the form of a bent sheet metal stamped part. The connection conductors 14 are inserted between the connection base 3 and the housing pot 4 or are also held in the connection base 3 by extrusion coating. Towards the top 5, the signal connections 13 are protected against contact by a separate, snap-on plastic cover 15.

Fig. 3 shows the power relay 1 in a partially disassembled state. It can be seen from this illustration that the power relay 1 is formed from four, in each case interconnected modules. In addition to the housing parts already described, namely the connection base 3 with the connecting bolts 10 and signal connections 13 fastened thereon, and in addition to the housing pot 4, the power relay 1 accordingly comprises a coil assembly 20 and a line carrier, hereinafter referred to as a board 21.

In the Fig. 4 Coil assembly 20, shown enlarged, comprises a contact bridge 22, which is connected via a coupling rod 23 to a magnet armature 24 Fig. 6 separately shown magnetic circuit is mechanically coupled. As can be seen in particular from this illustration, the magnetic circuit comprises, in addition to the magnet armature 24, a magnet yoke 25, this magnet yoke 25 being formed by a central hollow cylindrical core 26 concentrically surrounding the coupling rod 23, a U-shaped bow 27 and two of the leg ends of the Bracket converging pole shoes 28 is formed. The pole shoes 28 enclose the magnet armature 24 between them. The magnet armature 24 and the components of the magnet yoke 15 are formed from ferromagnetic material.

In the illustrated embodiment, the power relay 1 is a bistable relay. In this case, the plate shoes 28 and the leg ends of the bracket 27 are each arranged between two plate-shaped permanent magnets 29. Depending on the design of the power relay 1, however, one or two of the permanent magnets 29 assigned to a pole piece 28 can also be replaced by ferromagnetic plates of the same size. In a (not shown) monostable variant of the power relay 1, the permanent magnets 29 are completely replaced by ferromagnetic material.

As the eponymous component, the coil assembly 20 comprises a magnet coil 30 ( Fig. 4 ), which lies in the volume framed by the magnetic yoke 25. The magnetic coil 30 surrounds the core 26 of the magnetic yoke 25 concentrically and is in turn framed by the bracket 27 and the pole pieces 28.

• einen Schaltstellungskontakt 31 mit zwei Festkontakten 32 und einem mit der Koppelstange 23 gekoppelten Bewegkontakt 33,
• zwei Freidioden 34, die zum Schutz gegen induktive Spannungsstöße beim Schalten dienen sowie
• eine Thermosicherung 35, die eine Zwangsabschaltung des Leistungsrelais 1 bei Überhitzung bewirkt.

Ferner umfasst die Spulenbaugruppe 20 zwei Hilfsleiter 36, die jeweils aus einem gebogenen Blechstanzteil gebildet sind, ein Dämpfungselement 37 sowie zwei die Koppelstange 23 umgebende Druckfedern, nämlich eine Rückstellfeder 38 und eine Kontaktdruckfeder 39 (Fig. 12 und 13).How in particular from Fig. 5 emerges, the coil assembly 20 further comprises a number of electrical functional elements, namely

• a switch position contact 31 with two fixed contacts 32 and a moving contact 33 coupled to the coupling rod 23,
• two free diodes 34, which serve to protect against inductive voltage surges when switching as well
• a thermal fuse 35, which causes the power relay 1 to be switched off in the event of overheating.

Furthermore, the coil assembly 20 comprises two auxiliary conductors 36, each of which is formed from a bent sheet metal stamped part, a damping element 37 and two compression springs surrounding the coupling rod 23, namely a return spring 38 and a contact pressure spring 39 ( Fig. 12 and 13 ).

The above-listed components of the coil assembly 20 are mechanically held together by a carrier body 40, which in the 7 to 9 is shown in isolation. The carrier body 40 is a one-piece, multifunctional injection molding component made of plastic.

On the one hand, the carrier body 40 carries the magnetic coil 30, which for this purpose is wound directly onto a central column 41 of the carrier body 40. On the other hand, the carrier body 40 holds the magnet yoke 25 and the magnet armature 24. For this purpose, the magnet armature 24 and the core 26 of the magnet yoke 25 are accommodated in the interior of the hollow column 41 of the carrier body 40 (cf. 12 to 14 ). The magnet armature 24 is slidably mounted directly on the carrier body 40. The bracket 27 of the magnetic yoke 25 is placed on an upper platform 42 of the carrier body 40, so that its legs protrude laterally outside the magnetic coil 30. The pole shoes 28 and the permanent magnets 29 of the magnetic yoke 25 lie in two pockets 44 placed opposite one another in a lower platform 43 of the carrier body 40. How in particular from Fig. 9 emerges, each of the two pockets 44 is delimited on the inside - thus towards the hollow interior of the column 41 - by a thin wall 45 of the support body 40, which has a defined, constant wall thickness of 0.3 mm everywhere. A defined gap width between the magnet yoke 25 and the magnet armature 24 is hereby set by the walls 45.

• Halterungen 46 für die Festkontakte 32 des Schaltstellungskontakts 31,
• Bauraum 47 für die Freilaufdioden 34 (die Freilaufdioden 34 sind in dem dargestellten Ausführungsbeispiel nur indirekt über Spulenanschlussleiter an dem Trägerkörper 40 gehaltert),
• Halterungen 48 für die Thermosicherung 35,
• Halterungen 49 für die Hilfsleiter 36 sowie
• Halterungen 50 für das Dämpfungselement 37

auf. Bestimmungsgemäß werden hierbei identische Trägerkörper 40 für unterschiedliche Bauformen des Leistungsrelais 1 eingesetzt. Der Trägerkörper 40 weist die jeweils angeformten Halterungen 46 bis 50 somit auch dann auf, wenn bei einer bestimmten Bauform des Leistungsrelais 1 nicht alle der vorstehend beschriebenen Funktionsbauteile (also der Schaltstellungskontakt 31, die Freidioden 34, die Thermosicherung 35, die Hilfsleiter 36 oder das Dämpfungselement 37) vorhanden sind.Furthermore, the carrier body 40 has, as in particular Fig. 8 it can be seen

• Brackets 46 for the fixed contacts 32 of the switch position contact 31,
• Installation space 47 for the freewheeling diodes 34 (in the exemplary embodiment shown, the freewheeling diodes 34 are only held indirectly on the carrier body 40 via coil connecting conductors),
• Brackets 48 for the thermal fuse 35,
• Brackets 49 for the auxiliary conductors 36 and
• Brackets 50 for the damping element 37

on. As intended, identical carrier bodies 40 are used here for different types of power relay 1. The carrier body 40 thus has the respective molded-on brackets 46 to 50 even if, in the case of a specific design of the power relay 1, not all of the functional components described above (that is to say the switch position contact 31, the free diodes) 34, the thermal fuse 35, the auxiliary conductor 36 or the damping element 37) are present.

In the Fig. 3 The printed circuit board 21 is formed from two sections 60 and 61, which are connected to one another in an articulated manner via a film joint 62 and therefore from a planar original state into the one shown in FIG Fig. 3 L-shaped arrangement shown are bendable. In the illustrated electronic design of the power relay 1, the section 60 carries control electronics 63. The section 61 mainly contains contact points for the electrical contacting of the fixed contacts 32 of the switching position contact 31, the coil connections with the freewheeling diodes 34, the thermal fuse 35, the auxiliary conductor 36 and the solenoid coil 30 .

In the case of purely electromechanical designs of the power relay 1, the board 21 is optionally also present. In this case, however, it does not carry any control electronics 63, but only conductor tracks for contacting the magnetic coil 30 and any electrical functional elements which may be present with the signal connections 13. Alternatively, the board 21 is replaced by wire conductors in the case of purely electromechanical designs of the power relay 1.

In the course of the assembly of the power relay 1, the carrier body 40 with the magnet coil 30, the magnet yoke 25, the magnet armature 24 connected to the coupling rod 23 and the compression springs 38, 39, the contact bridge 22 and any electrical functional components (i.e. the switch position contact 31 , the freewheeling diodes 34, the thermal fuse 35 and / or the auxiliary conductors 36) and equipped with the damping element 37. The coil assembly 20 is thus completed as a self-stable (self-supporting) unit.

In this form, the coil assembly 20 is clipped from below onto the connection base 3, which was previously completed in an injection molding process. For this purpose, the connection base 3 is molded on its underside with snap hooks 64 ( Fig. 3 ), which engage under the upper platform 42 of the carrier body 40 on both sides. In the state of the coil assembly attached to the connection base 3 20 the bracket 27 of the magnetic yoke 25 continues to grip with two molded projections 65 ( Fig. 3 and 4th ) in a form-fitting manner in complementarily shaped depressions on the underside of the connection base 3. Thus, the clip 27 of the magnetic yoke 25 is connected in the clipped-on state in a rotationally fixed manner with respect to a rotation about the axis of the magnetic coil or the respective axis of the connecting bolts 10 with the connecting base 3.

After, before or at the same time as the coil assembly 20 is clipped on, the circuit board 21 is mounted. For this purpose, on the one hand connection points in the area of section 60 are soldered to the connection conductors 14 of the signal connections 13. On the other hand, connection points in the area of the section 61 are soldered to connections of the magnetic coil 30 and the existing electrical functional elements (that is to say the fixed contacts 32 of the switching position contact 31, the freewheeling diodes 34, the thermal fuse 35 and / or the auxiliary conductor 36). In its assembly position, the circuit board 21 extends with its section 60 parallel to one leg of the bracket 27, the section 60 being arranged outside the bracket 27. With its section 61, the board 21 extends perpendicular to the coil axis, engaging under the magnet yoke 25 and the magnet armature 24.

Furthermore, the auxiliary conductors 36 with (voltage tap) connections 66 ( Fig. 3 and 13 ) soldered. The connections 66 are assigned to the connection bolts 10 in pairs. One of the connections 66 is thus in contact with one of the connection bolts 10, while the other connection 66 is in contact with the other connection bolts 10. For this purpose, the connections 66 are welded beforehand to the respectively assigned connection bolt 10 and are extrusion-coated together with the plastic material of the connection base 3.

After the assembly of the coil assembly 20 and the circuit board 21 on the connection base 3, the housing pot 4 is placed over the coil assembly 20 and the circuit board 21 and latched and screwed to the connection base 3, whereby the housing 2 is closed. The bracket 27 of the magnetic yoke 25 lies in the housing pot 4 such that its legs are in the manner of cross members between two opposite side walls 6 of the Housing pot 4 and parallel to the remaining side walls 6 extend over the entire width of the housing interior 8. The bracket 27 is thus rotatably received in the housing pot 4 over the entire height of the housing pot 4, measured in the direction of the coil axis and the axis of the housing pot 4. Due to its torsionally stable structure, the bracket 27 thus stiffens the housing cup 4 with respect to axial torques, such as are exerted on the connecting bolts 10 in particular when the contact nuts are tightened.

When the housing 2 is closed, the connection base 3 lies with a circumferential radial web 70 ( Fig. 3 , 12th and 13 ) on a circumferential paragraph 71 ( Fig. 3 , 12th and 13 ) in the wall of the housing pot 4. The housing pot 4 engages here with a circumferential collar 72 ( Fig. 3 , 12th and 13 ) around the outside and around the radial web 70 of the connection base 3. The collar 72 thus surrounds the top of the radial web 70 like a balustrade and, together with the connection base 3, forms one - from the Fig. 12 and 13 apparent - trough-shaped structure, hereinafter referred to as tub 73. For the liquid-tight and gas-tight sealing of the connection between the connection base 3 and the housing pot 4, this trough 73 is filled with an initially liquid casting compound 74 which hardens in the course of a hardening phase. A two-component system consisting of an epoxy resin and an admixed hardener is used in particular as casting compound 74.

The feedthroughs of the connecting conductors 14 are also sealed with the sealing compound 74. For this purpose, the connection conductors 14 are guided through the connection base 3 in the region of the tub 73. The leadthroughs of the connection bolts 10 through the connection base 3 are sealed separately from the trough 73 by casting compound.

In order to additionally secure the connection between the connection base 3 and the housing pot 4, a number of radial projections 80 (in particular in the straight sections of the collar 72) are provided along the inside of the collar 72. Fig. 3 , 10 and 11 ) provided starting from the inner Project the wall of the collar 72 inwards. The radial projections 80 act on the one hand as latching lugs which engage around the radial web 70 of the connection base 3 and thus latch in its mounting position. Furthermore, each radial projection 80 is provided with an undercut 81 on both sides, so that each radial projection (80) has a dovetail-shaped contour when viewed from above. Due to the undercuts 81, the radial projections 80 cling to the sealing compound 74, thereby preventing both rotation of the housing pot 4 relative to the connection base 3 and radial bulging of the side walls 6 of the housing pot 4.

In order to prevent the potting compound 47 from being entrained with the housing pot 4 under the action of forces acting on the side walls 6 of the housing pot 4 and thereby detaching from the outside of the connection base 3, a number of counter contours are in the form of the top side of the connection base 3 formed by projections 82. The respective inner edges of these projections in turn form an undercut 83, which claws with the sealing compound 74.

In alternative designs (not shown), the power relay 1 is designed with multiple poles, in particular two-pole or three-pole. In this case, a number of coil assemblies 20 corresponding to the number of poles are connected to a common connection base 3, 2 connection bolts 10 being fixed in each case in the connection base 3 for each coil assembly 20. Depending on the design, a separate circuit board 21 can be provided for each coil assembly 20 or a common circuit board for all coil assemblies 20. In the case of multi-pole designs of the power relay 1, a housing pot 4, which is advantageously divided by transverse walls, is preferably provided to accommodate all the coil assemblies 20.

The 12 to 14 show the power relay 1 in the fully assembled state. It can be seen from these representations that the connecting bolts 10 each also form fixed contacts of the main switching device of the power relay 1 provided for switching the load circuit. The one from the bottom of the connector base 3 ends of the connecting bolts 10 protruding into the housing interior 8 are each provided with a contact element 90 for this purpose. The corresponding moving contact of the main switching device is formed by the contact bridge 22 which, in contrast to each of the contact elements 90, comprises a respective counter contact element 91. The mating contact elements 91 are electrically short-circuited within the contact bridge 22.

The Fig. 12 and 13 show the power relay 1 in an open position in which the mating contact elements 91 are lifted (decontacted) from the contact elements 90, so that there is no electrically conductive connection between the connecting bolts 10. The solenoid 30 is energized to switch on the power relay 1. As a result, a magnetic flux is generated in the magnetic yoke 25, by means of which the magnet armature 24 is attracted against the core 26 of the magnetic yoke 25. With the magnet armature 24, the contact bridge 22 is hereby deflected upwards, mediated by the coupling rod 23, so that the mating contact elements 91 abut the corresponding contact elements 90. In the closed position of the power relay 1 produced in this way, a conductive connection between the connecting bolts 10 is formed via the contact bridge 22.

To switch off the power relay 1, the solenoid 30 is energized with reverse polarity. Under the effect of the magnetic flux generated in the magnetic yoke 25, the holding force generated by the permanent magnets 29 is compensated for, so that the magnet armature 24 is pulled away from the core 26 by the return spring 38 and thus into the open position Fig. 12 and 13 is pressed. The magnet armature 24 in turn takes the contact bridge 22 via the coupling rod 23, as a result of which the counter-contact elements 91 are decontacted by the corresponding contact elements 90, with the electrical connection between the connecting bolts 10 being separated. The damping element 37 attached to the lower end of the carrier body 40 intercepts this movement and thus prevents the unit formed from the magnet armature 24, the coupling rod 23 and the contact bridge 22 from springing back in the direction of the Closed position. In addition, the play of the components of the coil assembly 20 is reduced by the damping element 37.

In the illustrated, bistable design of the power relay 1, each of the two switching positions of the power relay 1 is stable even when the solenoid 30 is de-energized. The magnetic coil 30 only has to be energized temporarily.

In a (not explicitly shown) design variant of the power relay 1, the coupling rod 23 projects upwards with a bearing section, that is to say beyond the side of the contact bridge 22 remote from the anchor. The bearing section plunges into an aligned bearing opening 92 of the connection base 3, so that the coupling rod 23 is also slidably mounted in the connection base 3. This ensures a particularly stable and precise positioning of the contact bridge 22.

How in particular from Fig. 12 emerges, the section 60 of the board 21 is arranged in the assembled state of the power relay 1 between one leg of the bracket 27 and the adjacent side wall 6 of the housing pot 4. The control electronics 63 arranged on the section 60 are thus thermally shielded by the bracket 27 from the heat generated when the solenoid 30 is energized. Consequently, the control electronics 36 are located in a cold area of the housing 2, which prevents premature aging of the control electronics 63.

The solenoid 30 is controlled either directly via the signal connections 14 or via the control electronics 63, which in the exemplary embodiment shown is in turn supplied with voltage via the connections 66 and the auxiliary conductors 36. The control electronics 63 controls the magnetic coil 30 as a function of external or internal control commands which are supplied to the control electronics 63 via the signal connections 13. Via the connections 66, the control electronics 63 also determines, in the switched-on state of the power relay 1, the voltage drop across the connection bolt 10 as a measure of the voltage generated by the Power relay 1 flowing load current or to detect the relay position. The control electronics 63 optionally implement an overload shutdown and a short-circuit shutdown by automatically moving the power relay 1 to the open position when the detected load current exceeds predetermined threshold values. In the case of multi-pole designs of power relay 1, control electronics 63 optionally also evaluate the voltages falling across the connecting bolts 10 of the individual poles in order to switch off power relay 1 - depending on the design - when a fault current or an asymmetrical current distribution is detected.

Finally, the control electronics 63 optionally have a contact cleaning function. In a corresponding contact cleaning mode, the control electronics 63 actuate the solenoid 30 several times at short time intervals in succession at regular time intervals, so that an artificial contact bounce is generated. Here, the contact bridge 22 strikes the connecting bolts 10 several times, as a result of which any adhering contaminants are rubbed off on the contact elements 90 and the counter-contact elements 91. The control electronics 63 first check the electrical voltage present via the connecting bolt 10 and only switch to contact cleaning mode when this voltage has a negligible amount and the power relay 1 can thus be switched to be load-free.

Particularly when the power relay 1 is switched off in the event of an overload or short circuit, the overheating of the current-carrying parts and the resulting switching arc regularly result in a high overpressure in the interior of the housing 8. Under unfavorable circumstances, this overpressure can assume a value that increases the stability of the housing 2 , in particular the housing pot 4 or the connection between the connection base 3 and the housing pot 4 are at risk. In order to prevent the housing 2 from exploding or uncontrolled bursting under these circumstances, the housing pot 4 is therefore provided with an overpressure safety device 100.

How out Fig. 15 is recognizable, this overpressure safety device 100 is formed by a curved groove, which locally reduces the material thickness of the housing base 7 and thereby acts as a predetermined breaking point 101. A predetermined keyhole-shaped tab 102 is delimited from the housing base 7 on three sides by the predetermined breaking point 101. A further groove extends between the ends of the predetermined breaking point 100, thus at the narrow end of the keyhole-shaped tab 102, which groove has a smaller groove depth than the predetermined breaking point 101 and therefore acts as a film joint 103. The predetermined breaking point 101 is dimensioned such that it bursts open when the pressure in the housing interior 8 exceeds a critical limit value of, for example, about 2 to 3 bar. In this case, the tab 102 is bent outwards around the film joint 103 and thus opens a gas ejection opening, via which pressure equalization with the surroundings takes place.

In a preferred embodiment of the power relay 1, an electrical signal line (not explicitly shown) in the form of a vapor-deposited or glued-on conductor track is placed on the inner wall of the housing base 7 across the predetermined breaking point 101 and the tab 102, the electrical contact resistance of which is queried by the control electronics 36. In this case, the signal line is automatically cut through when the predetermined breaking point 100 bursts open, which is recognized by the control electronics 63 due to the sudden increase in volume resistance. In this case, the control electronics 63 puts the power relay 1 in a safe state. In a construction variant expedient for many applications, the control electronics 63 triggers a permanent forced shutdown of the power relay 1 in order to force an exchange of the power relay 1.

How out Fig. 2 two alternative mounting options are specified for power relay 1. For example, the housing pot 4 has a mounting surface 110 on the outside both on a side wall 6 and on the housing base 7. Four screw openings 111 are provided on each mounting surface 110, to which the power relay 1 is intended to be mounted either directly or via an intermediate adapter plate by means of corresponding fastening screws can be. The screw openings 101 are preferably formed by threaded sleeves made of metal, which in the associated recesses (Blind holes) are pressed or screwed into the plastic material of the housing pot 4 or are extrusion-coated with the plastic material.

The invention is particularly clear from the exemplary embodiments described above, but is nevertheless not restricted to these exemplary embodiments. Rather, numerous other embodiments of the invention can be derived from the claims and the above description.

Reference list

1

Power relay

2nd

casing

3rd

Connection base

4th

Housing pot

5

Top

6

Side wall

7

Case back

8th

Housing interior

9

bottom

10th

Connecting bolts

11

Threaded shaft

12th

partition wall

13

Signal connection

14

Connection conductor

15

cover

20

Coil assembly

21

circuit board

22

Contact bridge

23

Coupling rod

24th

Magnetic anchor

25th

Magnetic yoke

26

core

27

hanger

28

Pole pieces

29

Permanent magnet

30th

Solenoid

31

Switch position contact

32

Fixed contact

33

Moving contact

34

Free-wheeling diode

35

Thermal fuse

36

Auxiliary leader

37

Damping element

38

Return spring

39

Contact pressure spring

40

Carrier body

41

pillar

42

(upper) platform

43

(lower) platform

44

bag

45

wall

46

bracket

47

bracket

48

bracket

49

bracket

50

bracket

60

section

61

section

62

Film hinge

63

Control electronics

64

Snap hook

65

head Start

66

(Voltage tap) connection

70

Radial web

71

paragraph

72

collar

73

Tub

74

Sealing compound

80

Radial projection

81

Undercut

82

head Start

83

Undercut

90

Contact element

91

Mating contact element

92

Warehouse opening

100

Overpressure protection

101

Predetermined breaking point

102

Tab

103

Film hinge

110

Mounting surface

111

Screw opening

Claims (2)

1. Power relay (1) for a vehicle, in particular for a utility vehicle,

   - with a housing (2) that is formed from a connector base (3) and a housing can (4) installed thereon,

   - with two connecting bolts (10) introduced into the connector base (3) for contacting with a load current circuit,

   - with a coil assembly (20) arranged in the housing (2), said coil assembly comprising a magnetic coil (30) and a magnetic armature (24), wherein the magnetic armature (24) is coupled to a contact bridge (22) via a forcetransmission member (23) and under the effect of a magnetic field generated by the magnetic coil (30) can be displaced in the housing (2) in such a way that the contact bridge (22) can be reversibly moved between a closed position, in which the contact bridge (22) bridges the connecting bolts (10) in an electrically conductive manner, and an open position in which the contact bridge (22) is not in contact with the connecting bolts (10), wherein the housing can (4) is formed as a plastic injection moulded component,

   characterized in
   that the housing (2) has an overpressure relief device (100) which releases a gas emission opening in the event of a critical overpressure in the housing (2), the overpressure relief device (100) being formed by a predetermined breaking point (101) moulded into the housing (2), an electrical safety line being mechanically coupled to the predetermined breaking point (101) in such way that, in the event of failure of the predetermined breaking point (101), the safety line is severed or electrically through-switched, wherein the safety line is in operative connection with the magnetic coil (30) in such way that the severing or through-switching of the safety line that takes place in the event of failure of the predetermined breaking point (101), causes a permanent electrical forced disconnection of the power relay (1).
2. Power relay (1) according to Claim 1,
   wherein the predetermined breaking point (101) surrounds a tab-like section (102) of the housing (2) from three sides, and wherein the fourth side of the tab-like section (104) is formed as a film hinge (103) along a connecting line extending between the ends of the predetermined breaking point (101).

Images