DE102023206229A1 - Method for establishing an electrical connection between a printed circuit board and a connecting wire and electrohydraulic actuator - Google Patents

Abstract

The invention relates to a method for producing an electrical connection between a printed circuit board (1) and a connecting wire (2), wherein the printed circuit board (1) is provided with a metallization surface (11), comprising the following steps:
- providing a housing part (7) which is provided with a wall (72) and at least one projection (75) protruding from the wall (72),
- applying a material coating (16) of an electrically conductive paste (17) in a locally limited area (74) outside the projection (75) to the wall (72) of the housing part (7),
- placing a section (21) of the connecting wire (2) on the material deposit (16), wherein the section (21) of the connecting wire (2) adheres to the material deposit (16) with its outer sheath (22),
- placing the printed circuit board (1) on the housing part (7) in such a way that the metallization surface (11) of the printed circuit board (1) faces the section (21) of the connecting wire (2) and
- Pressing the circuit board (1) in the direction of the wall (72) of the housing part (7) until the circuit board (1) comes into contact with the projection (75), wherein the section (21) of the connecting wire (2) is pressed from the metallization surface (11) into the material application (16) until the electrically conductive paste (17) of the material application (16) covers the metallization surface (11) of the circuit board (1).

Description

State of the art

In the prior art, for example, electrohydraulic actuators are used for controlling hydraulic systems that have an electromagnet with a magnetic coil and a valve part with a valve element. The valve element actuated by the electromagnet can open or close various inlet and outlet openings on the valve part and thereby adjust the pressure on one or more hydraulic consumers or a pressure channel. Such electrohydraulic actuators can be controlled via a control unit that adjusts the electrical current through the magnetic coil of the electromagnet.

In the state of the art, electrohydraulic control devices are used to control the electrohydraulic actuators. These are used, for example, in the transmission in automotive engineering and are usually designed as complex electronic modules with pressure sensors, speed sensors and other functions and can be used to control several electrohydraulic actuators. For example, DE 101 30 833 B4 an electrohydraulic control device is known which has a hydraulic block with hydraulic channels and an assembly side. Several electrohydraulic actuators are arranged on the hydraulic block, each of which engages with a valve section from the assembly side into a receiving opening in the hydraulic block. An electronic control unit comprises a circuit board designed as a large-area connection insulation layer with conductor tracks embedded in it. A central section of this circuit board functions as a circuit carrier and is equipped with the electronic components of a control circuit, which are covered with a cover part placed on the circuit board. The circuit board is led outwards laterally over the cover part and has electrical contact means on its edges, each of which is electrically contacted with the electrical connections of an electrohydraulic actuator.

In the known solutions, all actuators are usually controlled via a common electronic control unit (ECU), which can determine the required actuating currents for the actuators, for example via a microprocessor, and provides the actuating currents for the actuators' electromagnets via output stage modules integrated into the control unit. The ECU has several output stages, so that several actuators can be controlled via this ECU.

New developments and fields of application require that the electrohydraulic actuators are no longer operated via an output stage module in a central control unit, but are preferably addressed via a BUS system (e.g. CAN or LIN). However, the actuating current required to generate the actuating forces must then be generated in or on the actuator from a battery voltage. There is therefore a need for hydraulic actuators (so-called "smart actuators") that can be installed into a small, flexibly usable unit with an electronic control unit arranged directly in or on the actuator and assigned to the actuator.

This raises the fundamental problem of how a coil winding of an actuator electromagnet is to be electrically connected to the control unit's circuit board. The coil winding of an electromagnet has a very thin wire that is rather slack. Mounting the connecting wire in the through-hole mounting known for circuit boards in a contact opening of the circuit board, similar to the conventional electronic wire components mounted on the circuit board, is therefore usually not possible or only possible with a high level of additional technical effort.

Known electrical connection techniques between the connecting wires of the coil winding of an electromagnet and a circuit board therefore use intermediate connection means to achieve reliable contact. For example, the DE 44 27 767 C2 a coil winding whose connecting wires are wound around the electromagnet's connector plug and are encased in a plastic coil housing. Exposed ends of the connector plugs are led out of the coil housing as connector tabs. The stable connector tabs can be used for further contact with the circuit board, whereby additional contact elements can be inserted between the connector tabs and the circuit board.

The DE 103 37 197 B4 For example, discloses further contacting via contact elements designed as spring elements, which are contacted with the coil winding as part of the electromagnetic actuator. The spring contact elements can be pressed against a metallization surface on a circuit board with their ends facing away from the actuator. However, these solutions take up a lot of installation space.

disclosure of the invention

• - Bereitstellen eines Gehäuseteils, welches mit einer Wandung und wenigstens einem gegenüber der Wandung vorstehenden Vorsprung versehen ist,
• - Auftragen eines Materialauftrags aus einer elektrisch leitfähigen Paste in einem lokal begrenzten Bereich außerhalb des Vorsprungs auf die Wandung des Gehäuseteils,
• - Auflegen eines Abschnitts des Anschlussdrahtes auf den Materialauftrag, wobei der Abschnitt des Anschlussdrahts mit seinem Außenmantel an dem Materialauftrag anhaftet,
• - Aufsetzen der Leiterplatte auf das Gehäuseteil derart, dass die Metallisierungsfläche der Leiterplatte dem Abschnitt des Anschlussdrahtes zuweist und
• - Anpressen der Leiterplatte in Richtung der Wandung des Gehäuseteils bis die Leiterplatte mit der ersten Seite an dem Vorsprung zur Anlage gelangt, wobei der Abschnitt des Anschlussdrahtes von der Metallisierungsfläche in den Materialauftrag eingedrückt wird, bis die elektrisch leitfähige Paste des Materialauftrags die Metallisierungsfläche der Leiterplatte bedeckt.

The invention relates to a method of electrical connection between a printed circuit board and a connecting wire, wherein the printed circuit board is provided with a metallization surface on at least a first side, characterized by the following steps:

• - providing a housing part which is provided with a wall and at least one projection protruding from the wall,
• - Applying a material layer of an electrically conductive paste in a locally limited area outside the projection onto the wall of the housing part,
• - placing a section of the connecting wire on the material deposit, whereby the section of the connecting wire adheres to the material deposit with its outer sheath,
• - Placing the circuit board on the housing part in such a way that the metallization surface of the circuit board is aligned with the section of the connecting wire and
• - Pressing the circuit board in the direction of the wall of the housing part until the circuit board comes into contact with the projection with the first side, whereby the section of the connecting wire is pressed from the metallization surface into the material application until the electrically conductive paste of the material application covers the metallization surface of the circuit board.

The invention further relates to an electrohydraulic actuator produced using the method presented here, which has a valve part, an electromagnet with a coil winding, a magnet armature movably mounted in the electromagnet and a valve member actuated by the magnet armature and arranged in the valve part, wherein the electrohydraulic actuator further comprises at least one circuit board which is arranged on a wall of a housing part on at least one projection protruding from the wall, wherein the housing part is arranged on an actuator housing of the actuator and wherein at least one connecting wire of the coil winding is electrically conductively connected to a metallization surface of the circuit board by means of a material application of an electrically conductive paste arranged between the wall of the housing part and the metallization surface and covering the metallization surface.

In the context of the present application, an application of material from an electrically conductive paste is understood to mean an application of material from a viscous material with a sufficiently high viscosity (preferably over 10,000 cPs [cPs = centipoise]) so as not to flow away from the application site. The electrically conductive paste has a low modulus of elasticity and is therefore easily deformable under low pressure. It is preferably an electrically conductive adhesive, for example a silicone paste or a silicone adhesive.

Advantages of the invention

The method presented here describes a way of electrically and mechanically connecting a connecting wire to a metallization surface on a circuit board with just a few easy-to-manage process steps. To do this, a material layer of an electrically conductive paste is first applied in a localized area outside a projection on the wall of a housing part in a simple manner, which can be done using a dispenser, for example. The housing part can be designed in particular as a housing half-shell made of plastic and can serve to hold the conductor strip. The electrically conductive paste can in particular comprise an electrically conductive adhesive. A section of the connecting wire is then placed on the material layer, with the section of the connecting wire adhering to the material layer with its outer sheath. The section of the connecting wire can be freed from insulation covering the rest of the connecting wire and, if necessary, cleaned beforehand so that the electrically conductive material of the connecting wire is in direct contact with the material layer. In the next step, the circuit board is placed on the housing part, with the metallization surface of the circuit board facing the section of the connecting wire. In the last step, the circuit board is pressed towards the wall of the housing part, or pressed until the circuit board comes into contact with the projection with the first side. At the same time, the section of the connecting wire is pressed from the metallization surface into the material application until the electrically conductive paste of the material application covers the metallization surface of the circuit board. The connecting wire is now reliably electrically connected to the metallization surface of the circuit board via the electrically conductive paste.

Without being limited to this, the method is particularly suitable for a flexible connecting wire, in particular the connecting wire of a coil winding of a magnetic coil, which would not even be suitable for through-hole mounting. Apart from the material application of conductive paste, no other connecting means are required. In particular, no complex designed intermediate contact means are required. It is also not necessary to solder the connecting wire into the circuit board. Therefore, the manufacturing effort for the electrical connection between the connecting wire and the circuit board can be greatly reduced.

The integration of a control circuit into an electromagnetic actuator can only be achieved with a space-saving solution for the electrical connection between the circuit board and the connecting wires of the coil winding. The method presented here therefore represents a particularly suitable solution for this task, whereby the method requires only a few easily manageable connection steps and few components and enables a space-reduced electrical connection between a metallization surface of the circuit board of the control circuit and the coil winding of a magnetic coil. This simplifies or enables the integration of a control unit into an electromagnetic actuator (“smart actuator”).

Advantageous embodiments and further developments of the invention are made possible by the features contained in the dependent claims. The section of the connecting wire intended for embedding in the material coating can advantageously be circular in cross-section, which simplifies its introduction into the electrically conductive paste.

For a particularly reliable and stable electrical connection, the section of the connecting wire can advantageously be pressed so deeply into the material deposit that it is completely or almost completely embedded therein.

Advantageously, after the step of pressing the circuit board onto the at least one projection, the circuit board can be fastened to the housing part using fastening means, in particular screwable fastening means. The screwable fastening means can be screwed, for example, through a hole provided for this purpose in the circuit board into a receiving opening in the projection provided with a screw thread. Preferably, at least two or more projections are provided for stable fastening of the circuit board. This creates a compact assembly that can be further processed in a simple manner.

The method is, without being limited thereto, particularly advantageous for producing an electrical connection between a metallization surface of a circuit board intended for installation on or in an electrohydraulic actuator and at least one connecting wire of a coil winding of an electromagnet of the electrohydraulic actuator. The housing part can, for example, be made in particular as a housing half-shell made of plastic and serve to accommodate the circuit board. The circuit board is then mounted, for example, on an inner wall of the housing part. The housing part can then be fixed to an actuator housing, wherein the connecting wire of a coil winding, which is in contact with the circuit board via the electrically conductive paste, can easily be accommodated in the housing part.

Also advantageous is an electrohydraulic actuator produced using the method according to the invention, which has a valve part, an electromagnet with a coil winding, a magnet armature movably mounted in the electromagnet and a valve member actuated by the magnet armature and arranged in the valve part, wherein the electrohydraulic actuator has at least one circuit board which is arranged on a wall of a housing part on at least one projection protruding from the wall, wherein the housing part is arranged on an actuator housing of the actuator and at least one connecting wire of the coil winding is electrically conductively connected to a metallization surface of the circuit board by means of a material application of an electrically conductive paste arranged between the wall of the housing part and the metallization surface and covering the metallization surface.

Short description of the drawings

• 1 bis 5 einen Querschnitt durch einen Ausschnitt einer Leiterplatte während einer Abfolge von Verfahrensschritten für ein Ausführungsbeispiel des erfindungsgemäßen Verfahrens zur Herstellung einer elektrischen Verbindung zwischen einer Leiterplatte und einem Anschlussdraht,
• 6 einen mit dem erfindungsgemäßen Verfahren hergestellten elektrohydraulischen Aktuator.

Possible embodiments of the invention are explained below with reference to the accompanying figures. In the drawing:

• 1 until 5 a cross-section through a section of a printed circuit board during a sequence of method steps for an embodiment of the method according to the invention for producing an electrical connection between a printed circuit board and a connecting wire,
• 6 an electrohydraulic actuator manufactured using the method according to the invention.

embodiments of the invention

1 shows a cross-section through a section of a housing part 7. The housing part 7 is made, for example, as a housing half-shell made of plastic and has a wall 72, which is provided as the inside of an electronics housing, as well as an outer wall 73 facing away from the wall 72. In the embodiment shown here In the exemplary embodiment, the wall 72 has a platform, the top of which represents a locally limited area 74 of the wall 72, which is provided with a material application 16 made of an electrically conductive paste 17. The material application 16 can be applied, for example, using a dispenser. The paste 17 is sufficiently viscous and does not flow out of the area 74, but adheres there. The paste 17 can in particular have a viscous, pasty, electrically conductive adhesive, or consist of it. As in 1 As is further shown, the housing part 7 has at least one projection 75 which protrudes from the housing part 7 and the wall 72. In particular, several such projections are provided, of which in 1 however, only one is shown. The projection 75 protrudes from the wall 72 and extends on the side of the housing part 7 facing away from the outer wall 73 beyond the area 74 to approximately the height of the material application 16. In the exemplary embodiment shown, the front side of the projection 75, which is intended as a stop surface for a circuit board 1 and faces away from the housing part 7, is located somewhat below an upper side of the material application 16 facing away from the housing part 7. The projection 75 is formed, for example, by a dome-like extension of the housing part 7 with a circular cross-section, which has a central inner recess 76, which can be provided with an internal thread.

In a 2 In the further method step shown, a section 21 of a connecting wire 2 with its outer sheath 22 is laid flat on the material application 16 so that it adheres to it. The connecting wire 2 extends from a beginning to an end along an extension direction, or longitudinal extension direction, and preferably has a cylindrical outer sheath 22, which in cross section of the 2 (perpendicular to the direction of extension of the connecting wire) is recognizable as a circular cross-section. A section 21 of the connecting wire 2 intended for contacting, for example an end section of the connecting wire 2, is stripped and cleaned if necessary and laid flat on the material application 16 with the lower side of its outer sheath 22. The connecting wire 2 is, without being restricted to this, preferably a connecting wire of a coil winding 23 of an electromagnet, as will be explained below.

3 shows how, in a further method step, a printed circuit board 1 is placed on the housing part 7. The printed circuit board can be, for example, a conventional printed circuit board (PCB = printed circuit board), in particular a multi-layer printed circuit board made of epoxy resin with inner layers made of copper. The printed circuit board 1 has a first side 31 and a second side 32 facing away from the first side 31. The printed circuit board 1 has, for example, on the first side 31 a metallization surface 11 made of, for example, copper. A second metallization 12 can be arranged on the second side 32. In addition, the printed circuit board 1 can have a section (not shown) with further metallization surfaces. The printed circuit board 1 can be intended and provided to be equipped with the components of an electronic control circuit. On the first side 31, the printed circuit board 1 can be provided with a solder stop layer 14 which does not cover the inner region of the metallization surface 11, so that it is exposed. On the second side 32, the circuit board 1 has, for example, a second solder stop layer 14a, which can completely cover the metallization 12 there. Furthermore, the circuit board 1 has at least one opening 15, which completely penetrates the circuit board 1.

As in 3 As can be clearly seen, the circuit board 1 is placed on the housing part 7 in such a way that the metallization surface 11 of the circuit board 1 faces the section 21 of the connecting wire 2. The opening 15 is aligned centrally to the inner recess 76 of the projection 75. By pressing the circuit board 1 in the direction of the wall 72 of the housing part 7 (arrow direction in 3 ), the printed circuit board 1 comes to rest with the first side 31 on the front side of the projection 75 facing away from the printed circuit board 1.

The final state is in 4 The printed circuit board 1 rests with its first side on the projection 75. By pressing the printed circuit board 1, the section 21 of the connecting wire 2 was pressed from the metallization surface 11 into the material application 16 until the electrically conductive paste 17 of the material application 16 covers the metallization surface 11 of the printed circuit board 1. As in 4 As shown, the metallization surface 11 is preferably completely covered by the electrically conductive paste 17. As can be seen, the section 21 of the connecting wire 2 is pressed deep into the material layer 16 and is embedded in it. By pressing the circuit board 1 on, the material layer 16 was deformed and flattened and now covers the previously exposed area of the metallization surface 11.

Finally, as in 5 shown, at least one fastening means 18, for example designed as a screw, can be screwed through the at least one opening 15 of the circuit board 1 into the recess 76, which is preferably provided with the internal thread, so that the circuit board 1 is firmly connected to the housing part 7.

The method described is particularly suitable for producing an electrical connection between a metallization surface 11 on the surface of a circuit board 1 intended for installation on or in an electrohydraulic actuator 3 and at least one connecting wire 2 of a coil winding 23 of an electromagnet 51 of the electrohydraulic actuator 3.

In 6 an example of an electrohydraulic actuator 3 produced using the method according to the invention is shown. The electrohydraulic actuator 3 can have a valve part 6, an electromagnet 5 with a coil winding 23, a magnet armature 52 movably mounted in the electromagnet 5, and a valve member 61 actuated by the magnet armature 52 and arranged in the valve part 6, which is supported in the valve part 6 against a spring 62. By moving the valve member 61, inlet openings and outlet openings (not shown) of the valve part 6 for a hydraulic fluid can be opened or closed, whereby the hydraulic working pressure at a working connection of the valve part 6 can be adjusted. The electromagnet 5 is provided with an actuator housing 54 designed as a plastic housing, in particular by injection molding. The housing part 7 is attached to one side of the actuator housing 54. The housing part 7 can, as described above, be designed, for example, as a housing half-shell in which a circuit board 1 provided with a control circuit (not shown) is arranged. The circuit board 1 rests on several projections 75 to which the circuit board is screwed. The circuit board 1 is connected via electrical connecting means 71 to plug lugs 56 of a connection plug 55 of the electrohydraulic actuator 3, which are embedded in the actuator housing 54.

The electromagnet 5 comprises, for example, a pole tube 53 in which the magnet armature 52 is movably mounted. The magnet armature 52 is firmly connected to a tappet 58, which protrudes from the pole tube 53 at one axial end and acts on the valve member 61. The pole tube 53 is surrounded by a magnet coil with the coil winding 23. By energizing the coil winding 23, the magnet armature 52 is moved into 6 downwards. As a result, the tappet 58 presses the valve member 61 downwards against the spring force of the spring 62 in the valve part 6. By reducing the current strength, the magnetic force is reduced and the valve member 61 is moved into 6 moved back up.

As in 6 As can also be seen, the coil winding 23 has at least one connecting wire 2, which is led out laterally from the actuator housing 54. A contact section 21 of the at least one connecting wire 2 of the coil winding 23 is contacted with the metallization surface 11 on the circuit board 1 by the material application 16 with the electrically conductive paste 17.

The procedure can be such that the connecting wire 2 of the finished electromagnet 5 is connected to the housing part 7 after the 1 to 5 The flexibility of the connecting wire 2 makes it possible to subsequently pivot the housing part 7 towards the actuator housing 54 and to attach it laterally to the actuator housing 54 via a sealing ring, wherein the ends of the connecting means 71 facing away from the circuit board 1 can be pressed into end sections of the connector lugs 56. The connecting wire 2 is accommodated in the housing part 7 in a protected manner.

QUOTES INCLUDED IN THE DESCRIPTION

This list of documents listed by the applicant was generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA accepts no liability for any errors or omissions.

Cited patent literature

• DE 101 30 833 B4 [0002]
• DE 44 27 767 C2 [0006]
• DE 103 37 197 B4 [0007]

Claims (8)

Method for producing an electrical connection between a printed circuit board (1) and a connecting wire (2), wherein the printed circuit board (1) is provided with a metallization surface (11) on at least one first side (31), characterized by the following steps: - providing a housing part (7) which is provided with a wall (72) and at least one projection (75) protruding from the wall (72), - applying a material coating (16) made of an electrically conductive paste (17) in a locally limited area (74) outside the projection (75) to the wall (72) of the housing part (7), - placing a section (21) of the connecting wire (2) on the material coating (16), wherein the section (21) of the connecting wire (2) adheres to the material coating (16) with its outer jacket (22), - placing the printed circuit board (1) on the housing part (7) in such a way that the metallization surface (11) of the printed circuit board (1) to the section (21) of the connecting wire (2) and - pressing the circuit board (1) in the direction of the wall (72) of the housing part (7) until the circuit board (1) comes to rest with the first side (31) on the projection (75), wherein the section (21) of the connecting wire (2) is pressed from the metallization surface (11) into the material application (16) until the electrically conductive paste (17) of the material application (16) covers the metallization surface (11) of the circuit board (1). procedure according to claim 1 , characterized in that the electrically conductive paste (17) comprises an electrically conductive adhesive. procedure according to claim 1 or 2 , characterized in that the connecting wire (2) is a connecting wire of a coil winding (23). Method according to one of the preceding claims, characterized in that the section (21) of the connecting wire (2) is circular in cross section. Method according to one of the preceding claims, characterized in that the section (21) of the connecting wire (2) is pressed so deeply into the material deposit (16) that it is completely or almost completely embedded therein. Method according to one of the preceding claims, characterized in that the circuit board (1) is fastened to the housing part (7) by fastening means (18) after the step of pressing the circuit board (1) onto the projection (75). Method according to one of the preceding claims, characterized in that the method is used to produce an electrical connection between a metallization surface (11) on a circuit board (1) intended for installation on or in an electrohydraulic actuator (3) and at least one connecting wire (2) of a coil winding (23) of an electromagnet (51) of the electrohydraulic actuator (3). Electrohydraulic actuator (3) comprising a valve part (6), an electromagnet (5) with a coil winding (23), a magnet armature (52) movably mounted in the electromagnet (5) and a valve member (61) actuated by the magnet armature (52) and arranged in the valve part (6), characterized in that the electrohydraulic actuator (3) has at least one circuit board (1) which is arranged on a wall (72) of a housing part (7) on at least one projection (75) protruding from the wall (72), wherein the housing part (7) is arranged on an actuator housing (54) of the actuator, wherein at least one connecting wire (2) of the coil winding (23) is connected to a metallization surface (11) of the circuit board (1) by means of a material application (16) from a layer arranged between the wall (72) of the housing part (7) and the metallization surface (11) and the electrically conductive paste (17) covering the metallization surface (11) is electrically conductively connected.

Images