EP4341968A1

EP4341968A1 - Electric arrangement with a choke coil

Info

Publication number: EP4341968A1
Application number: EP22725422.4A
Authority: EP
Inventors: Wolfram Kienle; Friedemann Wolff; Christoph Jatzek
Original assignee: Robert Bosch GmbH
Current assignee: Robert Bosch GmbH
Priority date: 2021-05-18
Filing date: 2022-04-25
Publication date: 2024-03-27
Also published as: WO2022242987A1; US20240234012A1; KR20240009449A; DE102021205047A1; CN117321708A; JP2024518118A

Abstract

The invention relates to an electric arrangement (1), which comprises: a circuit substrate (2) with a plurality of terminal clips (3); and a choke coil (4) with conductors (5) having stripped terminals (6), each stripped terminal (6) being held in one of the plurality of terminal clips (3).

Description

description

title

Electrical arrangement with choke coil

State of the art

The present invention relates to an electrical assembly comprising a choke coil and a circuit substrate. In particular, the present invention relates to an electrical arrangement for controlling traction machines of electrically drivable means of transportation.

Toroidal core chokes are used in the filter units of electric vehicles for the electrical damping of interference frequencies. Here, the closed form is the electrically preferred design. However, the use of a closed choke when constructing the filter unit means that the current conductor has to be threaded through the choke and electrically connected again behind it. A double feedthrough of the current conductor proves to be of great advantage from an electrical point of view, since the square of the number of turns is included in the damping. The current conduction in the choke passage is very difficult to cool and thus leads to the heating of the choke core.

There is a need for a damping concept with double current feedthrough with simple assembly.

Disclosure of Invention

The present invention relates to an electrical assembly including a circuit substrate and a choke coil having conductors. The choke coil is disposed on the circuit substrate such that the stripped terminals of its conductors are received in a respective terminal bracket, the stripped terminals being held in each of the plurality of terminal brackets. In other words, connection clips are attached to the circuit substrate (eg glued, riveted, soldered, etc.), which have, in particular, an elastic mount for the stripped connections of the inductor coil conductors. In this case, the connection clips can be bent up elastically when the stripped connections are inserted and undercut according to a predefined path through the connection clips. In other words, the stripped wire end snaps into the terminal bracket and is secured against unwanted removal from the terminal bracket. A suitable geometric design of the connection clamps can ensure a large contact area with the respective stripped connection of the conductor. In particular, the surfaces of the stripped connections can correspond in sections to the connection clamps in order to ensure that the connection clamps lie flat against the stripped connections. In particular, the stripped terminals can have a substantially cylindrical conductor shape (eg in the manner of a copper wire), while the terminal clips have opposing jaws with cylindrically concave surfaces. In the installed state, the surface of the connection clip thus forms a jacket section surface for the stripped connections. In this way, assembly is simplified compared to arrangements known in the prior art and the positioning of the stripped connections in the connection clamps is (at least initially) reversible, so that a correction of stripped connections initially located in the wrong connection clamp is easily possible.

The dependent claims show preferred developments of the invention.

Preferably, the plurality of terminal clips may be electrically connected to a respective conductive trace on the circuit substrate. In other words, the terminal clips are electrically connected to a respective conductive trace on the circuit substrate to electrically connect the choke coil to the periphery surrounding it. The connection clamps can be soldered, welded, riveted, conductively glued or similar to the conductor tracks.

The stripped connections can preferably also be welded in the connection clamps. In other words, after the stripped connections have been inserted, the terminal clamp can be contacted from the outside by an electrode or two electrodes in such a way that when an electrical voltage is applied, the through the terminal clamps and the Welding current resulting from stripped connections leads to a material connection between the connections and the connection clamps. In this context, in particular, the connection clips can also be welded to the circuit substrate (eg to the respective conductor track). This results in the inductor being secured against mechanical and electrical decoupling from the circuit substrate.

For example, the support brackets and choke coil may be located entirely on one side of the circuit substrate. In this configuration, all of the components of the inductor (core assembly, electrical conductors, etc.) are arranged on the same side of the circuit substrate as the connection clips. However, at least one center of gravity of the inductor is on the same side of the circuit substrate as the connection clips. Alternatively, the choke coil or its center of gravity can be located on a side of the circuit substrate opposite the clamps and only the electrical conductors and stripped connections that are routed proportionally to the opposite side of the circuit substrate are located on the side of the connection clamps, with the stripped connections being arranged in the connection clamps are. With this configuration, the configuration can be kept flat with respect to a respective surface of the circuit substrate.

For example, the connection clips can have a base, which has a flat surface (mounting surface), for the planar and stable connection to the circuit substrate. As an alternative or in addition, holding lugs that curve over the base can be provided on both sides of the base for receiving the stripped connections. In this case, the connecting clip can be manufactured (bent) in one piece from a sheet metal part. Because of the retaining lugs that curve over the flat base, a spring deflection for setting a suitable, predefined prestressing of the retaining lugs can be ensured. In this way, the stripped connections can be held particularly securely and the retaining lugs can be contacted by welding electrodes conveniently and reliably next to the stripped connections.

In particular, the retaining lugs can have a depth that is less than a depth of the base. In other words, from a sheet metal strip On the one hand, the manufactured connection clip has a sufficiently large width/depth at the point where the base is in planar contact with the circuit substrate and a smaller width/depth of the retaining lugs that curve over the base can ensure that the prestress on the stripped connections is not too great in order to be able to insert them into the connection clamps in a process-reliable manner and without any risk to the surrounding components.

The retaining lugs can have distal ends which, when the stripped connections are inserted, are oriented in the direction normal to the surface of the circuit substrate and are the first to come into contact with the stripped connections during assembly of the inductor. These distal ends may have a contact surface to the stripped terminals that is substantially perpendicular to the surface of the circuit substrate. Two opposite distal ends clamp the stripped connections of the conductors of the choke coil between them. For this purpose, they can have a gap that tapers in the direction of the surface of the circuit substrate in order to facilitate threading in of the stripped connections and at the same time to ensure a sufficiently large prestress in an end position of the stripped connections. For this purpose, the distal ends in the area of the end position of the stripped connections can have an increased distance from one another, so that when the stripped connections are removed in a direction perpendicular to the surface of the circuit substrate, the distal ends necessarily first press the distal ends apart again until they have left (completely) through the stripped connections spring towards each other again. Compared to a region of the retaining lugs adjoining them, the distal ends are thus oriented more perpendicularly to the surface of the circuit substrate.

The choke coil may have a core assembly with an eyelet (bore) through which the conductors are routed. For example, three or four conductors can be routed through the eye and returned on an outside of the core assembly. Positioning aids/positioning structures can be provided in the eye and/or on an end face of the core assembly and/or on a lateral surface of the core assembly in order to simplify accurate and predefined positioning of the conductors during assembly of the inductor. The positioning structures can include webs and/or grooves, for example. They can run radially on the end face and/or run coaxially to the eye on the lateral surface. In particular, if the core assembly has an elastic surface (e.g. made of a suitable plastic, etc.), the conductors can be fitted into the grooves, in particular pressed in, and protected against accidental loosening or by a holding force of the positioning structures (Proportional) bending back towards an initial shape of the conductor are prevented.

The core assembly can further preferably have positioning aids which promote/facilitate positioning of the inductor coil on the circuit substrate. In particular, predefined structures of the core assembly can engage in corresponding recesses in the circuit substrate, so that the choke coil can be positioned in a torsion-proof manner relative to the circuit substrate.

In particular, a rotary position about a longitudinal axis can be encoded by the eye of the inductor during assembly, which only allows a single rotary position of the inductor with respect to the circuit substrate. An electrically incorrect assignment of the conductors to the connection clips can be effectively prevented in this way.

More preferably, the choke coil or the core assembly can have a mechanical stop which interacts with a corresponding structure (for example an edge/flange around a recess) in the circuit substrate. In other words, the choke coil can only be inserted through the circuit substrate up to a certain predefined depth in this way, until the stop is in contact with a surface of the circuit substrate (in particular over an area). This flange face can be bonded to the circuit substrate. The flange prevents the inductor from oscillating relative to the circuit substrate or tilting the inductor relative to the circuit substrate. In particular, it can be ensured that an overall height of the choke coil has particularly small tolerances relative to the surface of the circuit substrate. The stripped connections of the choke coil can each be led away from the coil in a radial direction in a star shape in a common plane. In other words, the stripped terminals gather in a common plane that is parallel to a surface of the circuit substrate. In this way, the multiplicity of connection clips can also have an identical structural shape and/or an identical height above the surface of the circuit substrate. A design of the electrical arrangement is reduced again in this way. In this case, the stripped connections or the connection clips can be arranged, in particular, equidistantly from one another. In other words, connecting clips adjacent to one another can each have an identical angle to one another. In particular, the stripped connections can have an angle of 45° to one another.

The electrical arrangement disclosed here can be prefabricated with simple conductor pieces. The dimensions of the parts must be adapted to the current-carrying capacity and the damping properties. The subsequent installation can be position-oriented and on a standard carrier (circuit substrate, printed circuit board, pre-molded stamped part, etc.) and avoids threading assembly with intermediate connection processes. In the final assembly, the choke coil can be added to a pot construction that is available for cooling and shielding. This component is therefore in its own EMC zone, which has a beneficial effect on damping.

Brief description of the drawings

Exemplary embodiments of the invention are described in detail below with reference to the accompanying drawings. In the drawing is:

Figure 1 is a perspective view of a choke coil for

Use in an electrical arrangement according to the invention;

Figure 2 is a perspective view of a choke coil according to

Figure 1 from below; FIG. 3 shows the arrangement shown in FIG. 2 after the conductors guided through the eye of the coil core have been aligned in the radial direction;

FIG. 4 shows a circuit substrate and a sectional illustration through a choke coil according to FIG. 3 in connection with a circuit substrate for mounting the choke coil on both sides; and

FIG. 5 shows a perspective view of the components shown in FIG. 4 and the arrangement of the stripped conductor ends in the terminal clamps shown in addition.

Embodiments of the invention

FIG. 1 shows a choke coil 4 with four electrical conductors 5, which have stripped connections 6 on both sides. The conductors 5 are inserted into positioning structures 9 arranged on the end face of the core assembly 8 . The positioning structures 9 are designed as parallel webs in pairs on both sides of the sections of the conductors 5 running in the radial direction. Two positioning aids 10 are also arranged on the core assembly 8 , which engage in recesses (not shown) in a circuit board (not shown) and prevent the inductance coil 4 from rotating relative to the circuit board.

FIG. 2 shows the choke coil 4 shown in FIG. 1 in an upside-down view. Positioning structures 9 in the form of webs are also provided on the opposite end face for the ends of the conductors 5 which are still aligned in the coaxial direction in the arrangement shown.

FIG. 3 shows the choke coil 4 shown in FIG. 2 after the conductors 5 protruding from the eye 14 of the core assembly 8 have been bent into the grooves provided by the webs 9 and have thus arrived in a radial alignment. The stripped conductor ends 6 are now all in a plane which runs normal to an axis through the eye 14 of the core assembly 8 . FIG. 4 shows a perspective representation of a circuit substrate 2, which has two recesses 11 corresponding to the protruding positioning aids 10 (FIG. 2). An arrangement of the choke coil shown in a sectional representation, which also has a stop 16, can therefore only take place in one direction of rotation. In addition, the recess 12 has bays for the sections of the conductors 5 running on the outside of the core assembly 8 . In this way, the conductors 5 are secured in the circuit substrate 2 after the choke coil 4 has been inserted into the recess 12 . The joining geometry (all of the recesses 11, 12 and the bays 15) in the circuit substrate 2 thus determines the position and orientation of the inductor coil 4 in its end position. The stop 16 can be glued to the surface of the circuit substrate 2 in the end position. Alternatively, a latching lug can also be arranged on the core assembly 8, which enables the inductor coil 4 to be fixed (temporarily or finally) in the circuit substrate 2.

FIG. 5 shows the components shown in FIG. 4 after assembly, the stripped connections 6 being held in connection clamps 3 . The connecting clamps 3 have a respective base 32 with a first (larger) depth T, which is followed by respective holding lugs 36 at opposite ends. The retaining lugs 36 have distal ends 35 which are essentially perpendicular to a surface of the circuit substrate 2 . The retaining lugs 36 have a depth t which is less than the depth T of the base 32 . The retaining lugs 36 first curve over the respective base 32 while their distal ends 35 are bent upwards in opposite directions to clamp the stripped terminals 6 in place. Three terminal clips 3 are connected to exemplary conductive traces 7 on the circuit substrate 2 . The electrical contact resistance between the stripped connections 6 and the connection clamp 3 can be further reduced by welding electrodes being placed on the retaining lugs 36 (and/or being attached to the distal ends 35) and a welding current connecting the components to one another in a materially bonded manner.

Claims

Expectations

1. Electrical arrangement (1) comprising

- a circuit substrate (2) with a plurality of terminal clips (3), and

- a choke coil (4) with conductors (5) which have stripped connections (6), the stripped connections (6) each being held in one of the plurality of connection clamps (3).

The electrical assembly of claim 1, wherein the plurality of terminal clips (3) are electrically connected to a respective conductive trace (7) on the circuit substrate (2).

3. Electrical arrangement according to claim 1 or 2, wherein the stripped connections (6) are welded in the connection clips (3).

4. Electrical arrangement according to one of the preceding claims, wherein

- The terminal clamps (3) and the choke coil (4) are arranged entirely on one side of the circuit substrate (2) or

- the terminal clamps (3) and a center of gravity of a core assembly (8) of the inductor (4) are arranged on different sides of the circuit substrate (2).

5. Electrical arrangement according to one of the preceding claims, wherein the connection clips (3) have:

- a flat base (32) resting on the circuit substrate (2) and/or

- retaining lugs (36) curving over the base (32) on opposite sides of the base (32).

6. Electrical arrangement according to claim 5, wherein the retaining lugs (36) have a depth (t) which is less than a depth (T) of the base (32) and / or having distal ends (35) oriented substantially perpendicular to the base (32).

7. Electrical arrangement according to one of the preceding claims, wherein the inductor (4) has a core assembly with an eye (14) through which the conductors (5) are guided, wherein the core assembly (8) in particular on an end face and / or has positioning structures (9) on a lateral surface, into which the conductors (5) are inserted, in particular pressed.

8. Electrical arrangement according to claim 7, wherein the core assembly (8) has protruding positioning aids (10) which engage in corresponding recesses (11) in the circuit substrate (2).

9. Electrical arrangement according to one of the preceding claims, wherein the choke coil (4) is guided through a recess (12) in the circuit substrate (2) to a side opposite the connection clips (3) with respect to the circuit substrate (2) and the core assembly (8) has a stop (15) which abuts against a surface of the circuit substrate (2) on the side of the terminal clips (3).

10. Electrical arrangement according to one of the preceding claims, wherein the stripped connections (6) are discharged in a star shape in a common plane in the radial direction.