WO2018024715A1 - Ultrasonic welding of a stranded conductor to a contact part by means of a contact plate - Google Patents

Abstract

Method for the ultrasonic welding of a stranded conductor (1) to a contact part (4), wherein a stripped portion (5) of the stranded conductor (1) with at least one strand (2), which comprises multiple individual wires (3) that are preferably twisted together, is arranged on a welding portion (6) of the contact part (4). To avoid damage to the individual wires, and thus ensure that the current carrying capacity remains the same, it is provided according to the invention that the method comprises the following steps: - arranging a contact plate (7) on the stripped portion (5) in such a way that a connecting portion (8) of the stripped portion (5) is arranged between the contact plate (7) and the welding portion (6); - pressing at least one sonotrode and at least one anvil lying opposite the at least one sonotrode against one another, wherein the sonotrode is pressed against the contact plate (7) and/or against the contact part (4) in the direction of the connecting portion (8); - ultrasonic welding by means of the at least one sonotrode.

Description

 ULTRASONIC WELDING OF A LADDER LEADER M IT A CONTACT PART OF IT

 A CONTACT LATCH

FIELD OF THE INVENTION

The present invention relates to a method for

Ultrasonic welding of a stranded conductor with a

Contact part, wherein a stripped portion of the

Stranded conductor with at least one strand, which has a plurality, preferably twisted, individual wires, is arranged on a welded portion of the contact part.

Furthermore, the present invention relates to a system for carrying out the method according to the invention.

STATE OF THE ART

From the prior art it is known that the electrical connection between an electrical conductor, the

in particular as a stranded conductor with a strand or several strands of, preferably twisted, individual wires

may be formed, and a contact part over a

Ultrasonic welding process can be produced. In order to establish the electrical connection, the stranded conductor is placed on a prepared for the welding surface of the contact part and both contact partners between the anvil and sonotrode of an ultrasonic welding tool are clamped. In general, the contact part lies on the anvil (dormant Tool), and the stripped stranded conductor faces the sonotrode.

The welding process is performed by the sonotrode acts with a defined force on the positioned contact partners and performs an oscillating movement with sufficient speed and thus the individual wires of the stranded conductor in relative movement to each other and to

Contact part offset. The heat generated by existing friction between the moving parts is used to connect the individual wires to each other and the strand (s) to the

 To weld contact part. The energy is like that

designed that occur only in the contact points diffusion processes, but not a melt is generated.

In order to be able to move the individual wires particularly efficiently, the sonotrode can be equipped with a special profile, which usually has grooves and / or points. This prevents a relative movement between these individual wires and the sonotrode to form on the uppermost layer of the individual wires (i.e., on the layer of individual wires which contact the sonotrode). Such

 Relative movement would be the top single wires with the

Sonotrode weld, which is unintentional. The concrete

The profiles used are typically manufacturer-specific and are usually optimized with regard to the material of the strands or to the hardness of this material.

The said profile and the generated during the welding process

However, heating leads to a very high deformation and mechanical damage to the top single wire layer. The individual wires of the uppermost layer have no

sufficient resistance to tensile and

 Bending stress on the stranded wire, resulting in broken wires and thus to a reduced

Current carrying capacity of the stranded conductor can lead. OBJECT OF THE INVENTION

It is therefore an object of the present invention to provide a

To provide improved ultrasonic welding method and a system for its implementation, the above-mentioned disadvantages are to be avoided. In particular, the individual wires of the stranded conductor to be welded during ultrasonic welding should as far as possible not be damaged, so that a constant current carrying capacity can be ensured.

PRESENTATION OF THE INVENTION

To solve the above object, it is in a method for ultrasonic welding a stranded conductor with a contact part, wherein a abgeschärbantelter section of

Stranded conductor with at least one strand, which has a plurality of, preferably twisted, individual wires, is arranged on a welded portion of the contact part,

According to the invention, the method comprises the following steps:

 Arranging a contact pad on the stripped portion such that a connecting portion of the

stripped portion is disposed between the contact pad and the welding portion;

 - Pressing against each other at least one sonotrode and

at least one of the at least one sonotrode

opposite abutment, wherein the sonotrode is pressed against the contact plate and / or against the contact part in the direction of the connecting portion;

 - Ultrasonic welding by means of at least one

Sonotrode. Through the contact plate is a top layer of the individual wires of the at least one strand before the direct

Contact with the sonotrode and in particular protected from a profile of a working surface of the sonotrode. The uppermost layer is the position of individual wires, whose

 Individual wires in the strand lie completely outside and are in direct contact with the contact plate. According to the prior art, the uppermost layer would be contacted with the sonotrode.

Expensive experiments have surprisingly shown that it is the ultrasonic welding between the

 Contact platelets and the individual wires of the top layer to a relative movement comes, which is completely analogous to

Relative movement of the individual wires to each other

Ultrasonic welding without contact plates according to the prior art. As a result, the contact plate transmits the energy introduced by means of the sonotrode to the

Single wires of the strand and ensures a friction welding, as occurs in conventional ultrasonic welding, safe. That the individual wires are welded together and with the contact part and the contact plate.

At the same time, the contact plate causes a particularly uniform distribution of the friction energy on the individual wires, in particular on the uppermost layer of the individual wires. This causes a particularly uniform welding of all

Single wires and prevents unacceptable deformation of the individual wires. It can only be a uniform deformation of the individual wires occur, but for the uppermost layer fails completely analogous to the bottom layer, which is referred to as the lowest layer that layer of individual wires whose

Individual wires in the strand lie completely outside and in direct

Contact the contact part. The mechanical stability and strength of the individual wires is thus maintained, so that all individual wires can contribute fully to the current carrying capacity of the stranded conductor. The welded single wires all have essentially the same mechanical

Strength.

When said pressing against each other, the pressure can be applied in principle from the side of the sonotrode or from the side of the abutment or from both sides. The described arrangement of contact plates, connecting section and

Welding section is between the at least one

Sonotrode and the at least one abutment arranged.

The pressing against each other and the ultrasonic welding can take place successively and / or simultaneously.

In particular, the same pressure that occurs during

Is built against each other, during

Ultrasonic welding are maintained.

As an abutment in a conventional manner, an im

Substantial immovable element, also referred to as anvil, may be used. It is also conceivable to use another sonotrode as an abutment. In this case, both the contact plate and the contact part would be contacted by at least one sonotrode. Finally, it would also be possible that the sonotrode the

Contact part contacted and the abutment the

Contact plates. In this case, takes over

Ultrasonically weld the contact plate the role of the contact part and vice versa. The process of ultrasonic welding by means of

at least one sonotrode finally takes place in a manner known per se.

Finally, it should be noted that the welding section of

Contact part is a section that is intended for welding with the individual wires. In a preferred embodiment of the method according to the invention, it is provided that the at least one

Sonotrode comprises a profiled work surface with which the sonotrode against a contact surface of the

Contact tip and / or the contact part is pressed, the sonotrode is pressed so strong against the contact pad and / or the contact part that in the

Contact surface is shaped a profile corresponding counter profile. As a result, a relative movement between the contact surface and the sonotrode is practically completely prevented, since not only a frictional connection (by the pressing against each other), but also a positive connection (by the profile and the counter profile) is given. An undesirable welding of the contact surface, in particular the contact surface of the contact plate, with the sonotrode can thus be excluded.

Instead, optimal energy transfer from the sonotrode to the contact surface takes place. If the contact surface is the contact surface of the contact pad, then this becomes a particularly uniform

 Relative movement of the individual wires to the contact plate and a correspondingly particularly uniform welding of

Single wires with the contact plate - but also

between each other - ensured. An undesirable deformation of the individual wires of the uppermost layer is thereby effectively prevented.

The embossing of the counterprofile in the contact surface,

In particular, in the contact surface of the contact plate, that is essentially carried out when pressing against each other, ie immediately before and / or during the Ultraschallverschweißens. Theoretically, it would be conceivable that the counter profile in the

Contact surface is already prefabricated. However, the production during the process according to the invention provides a perfect Positive locking safe and is also cheaper because of the pre-processing of the contact surface, in particular the

Contact surface of the contact plate, can be dispensed with.

Preferably, therefore, the contact plate initially has a smooth surface, in particular a smooth contact surface, wherein also the contact surface opposite

Surface of the contact plate can be smooth.

In a preferred embodiment of the method according to the invention, it is provided that the at least one

Abutment having a profile having work surface with which the abutment against a contact surface of the

Contact part and / or the contact plate is pressed, wherein the abutment is pressed so strong against the contact part and / or the contact plate that in the contact surface a profile corresponding counter profile is coined.

As a result, a relative movement between the contact surface and the abutment is practically completely prevented, since not only a frictional connection (by the pressing against each other), but also a positive connection (by the profile and the counter-profile) is given. An undesirable welding of the contact surface, in particular the contact surface of the contact part, with the

Abutment can thus be excluded.

If the contact surface is the contact surface of the contact part, then in the case of a substantially rigid abutment this in turn becomes a uniform one

Relative movement of the individual wires to the contact part at

Ultrasonic welding and a correspondingly uniform welding of the individual wires to the contact part

ensured. An undesirable deformation of the individual wires of the lowest layer is particularly effective

prevented. The embossing of the counterprofile in the contact surface,

In particular, in the contact surface of the contact part, that is essentially carried out when pressing against each other, ie immediately before and / or during the Ultraschallverschweißens. Theoretically, it would be conceivable that the counter profile in the

 Contact surface is already prefabricated. However, the production during the process according to the invention ensures a perfect fit and is also more cost-effective, since the preprocessing of the contact surface, in particular the

Contact surface of the contact part, can be dispensed with.

Preferably, therefore, the contact part initially has a smooth surface, in particular a smooth contact surface, wherein also the contact surface opposite surface of the contact part can be smooth. In a preferred embodiment of the invention

Method is provided that the individual wires are made of a metal and that the contact plate is made of the same metal or an alloy of the same metal. Under metal as usual not only the individual metal-forming elements, but also their

 To understand alloys. The individual wires can in particular be made of: aluminum, an aluminum alloy,

Copper, a copper alloy. By the contact plate of the same or a similar metal as the at least one strand or as the individual wires is made, are

different electronegativities of the contact plate and the individual wires avoided. In this case, different electronegativities can lead to electrochemical corrosion, which is avoided by said choice of material to a

to enable permanently reliable connection.

The contact part is typically made of copper or a

Made of copper alloy, but can also be made of aluminum or an aluminum alloy. The material of the Contact part may have a higher strength than the material of the individual wires. In any case, the contact part usually has a higher mechanical strength than the

Single wires on. In a preferred embodiment of the inventive method, it is provided that the contact plate has a thickness which is in the range of 1 to 3 times a diameter of the individual wires. Particularly preferably, the diameter of the individual wires is in a range from 0.05 mm to 2 mm, preferably from 0.1 mm to 1 mm. Through this

Thickness is a sufficient volume of

Contact plate is guaranteed to prevent impermeable deformations of the individual wires of at least one strand

to counteract effectively. In addition, a width of the contact plate to a width and / or a diameter of the at least one strand, in particular the

Connection section to be adjusted. Respectively. For example, a length of the contact pad can be adapted to a length of the connection section. The length of the contact pad is measured along a longitudinal axis of the contact plate, which runs parallel to a longitudinal direction, and the width of the contact plate along a direction normal to the longitudinal direction. When the contact pad according to the method of the present invention is disposed on the stripped portion and on the connecting portion, the length of the connecting portion along the same direction is measured as the length of the contact pad and the width of the connecting portion along the same direction as the width of the contact chip. The width of the contact plate can in particular be adapted to and correspond to a width of the welding tool, in particular the sonotrode and / or the anvil. It can be used to guide the contact plate lateral Abstützkörper which act as movable stops, be provided.

In a preferred embodiment of the method according to the invention, it is provided that, viewed in a longitudinal direction along a longitudinal axis of the contact wafer, the contact plate has an outlet zone in an end region

which, in ultrasonic welding, preferably faces a sheathed portion of the stranded conductor, wherein the ultrasonic welding, and preferably also the

Press against each other, seen in the longitudinal direction only in a front of the outlet zone arranged welding section of the

Contact tile takes place. That seen in the longitudinal direction of the sheathed section behind the outlet zone

arranged, wherein in general the stripped portion sections also between the outlet zone and the

Contact part can be arranged.

Mechanical loads, e.g. caused by vibration tensile and bending loads, attack the individual wires, especially in the end of the contact plate. The

Single wires are used in ultrasonic welding in

 Welding portion of the contact plate exposed to a certain heat, which may adversely affect the mechanical properties of the individual wires. By having the individual wires in the run-out zone, i. in said end region of the

Contact pads, not welded, will be a kind of buffer against the welded in this area

Individual wires in the welding section of the contact plate - more precisely: opposite those sections of the individual wires, which are arranged in the welded portion of the contact plate and

are welded - formed. In particular, the

Individual wires in the outlet zone have a certain mobility or elasticity, which is significantly greater than in the welded portion of the contact plate, where the individual wires are welded. This favors the elasticity buffer ^¬ or damping effect.

Moreover, by dispensing with pressing against each other in the outlet zone, it is ensured that the individual wires in the outlet zone can not be deformed or deformed by pressing against one another such that a certain mechanical weakening of the individual wires occurs. It is thus guaranteed that the individual wires in the

Outlet zone have optimal mechanical properties to absorb mechanical loads and against the

 Individual wires in the welding section of the contact plate - more precisely: opposite those sections of the individual wires, which are arranged in the welded portion of the contact plate and

are welded - to buffer or dampen. In a structurally particularly simple and thus

Cost-effective to be realized embodiment of the

The inventive method is provided that the

Ultrasonic welding is carried out by means of exactly one sonotrode, the sonotrode being pressed against the contact plate. Preferably, an anvil is provided as an abutment.

Analogously to the above, a system for carrying out the method according to the invention is provided according to the invention, the system comprising a stranded conductor with at least one

A strand having a plurality of, preferably twisted, single wires, the stranded conductor having a stripped portion, the system further comprising a contact portion having a weld portion on which the stripped portion is disposable, and a contact pad, the system being configured such that the Contact pad during the process on the stripped portion can be arranged to a connection portion of the stripped portion between itself and the ultrasonic welding

To absorb welding section. Preferably, this can be the Contact plate to be matched to the stranded conductor and the contact part. In particular, the contact plate in its choice of material and / or geometry and / or

Dimensioning adapted to the stranded conductor and / or the contact part, as above in connection with the inventive method and its preferred

Embodiments is described.

BRIEF DESCRIPTION OF THE FIGURES

The invention will now be explained in more detail with reference to an embodiment. The drawings are exemplary and are intended to illustrate the inventive idea, but in no way restrict it or even reproduce it.

Showing:

Fig. 1 is an axonometric view of a stranded conductor, which is welded to a contact part by an inventive method, obliquely from above

Fig. 2 is an axonometric view analogous to FIG. 1 of

 diagonally down

Fig. 3 is a sectional view of the contact part

 welded stranded conductor of FIG. 1

WAYS FOR CARRYING OUT THE INVENTION

In the axonometric view of FIG. 1, a stranded conductor 1 can be seen, which is ultrasonically welded to a contact part 4 by means of a method according to the invention. The stranded conductor 1 has a sheathed section 12, in FIG which is a strand 2 of an electrically insulating jacket 16, which may be made of plastic, for example, is surrounded. The strand 2 consists of a variety of

Individual wires 3, which are twisted. The individual wires 3 are made of a metal, such as aluminum or an aluminum alloy or copper or a

Copper alloy. The strand 2 is stripped in a

Section 5 (see Fig. 3) of the stranded conductor 1 exposed, i. in the stripped section 5, the jacket 16 is missing or has been removed.

The contact part 4 is also made of a metal,

typically copper or a copper alloy or aluminum or an aluminum alloy. The contact part 4 has a welding section 6 (see Fig. 3), which is designed in the illustrated embodiment is substantially planar and rectangular. On this welding portion 6 of the stripped portion 5, more precisely, a connecting portion 8 of the stripped portion 5, placed. According to the

The method according to the invention then becomes a contact plate 7, which consists of the same or a similar metal as the

Single wires 3 is arranged on the connecting portion 8, more precisely on a side opposite the contact part 4 of the connecting portion 8. This results in the recognizable in Fig. 1 arrangement of contact part 4,

Connecting portion 8 and contact plate 7, wherein the

Connecting portion 8 between the contact part 4 and

Contact plate 7 is located.

According to the method according to the invention takes place

Pressing against each other a known sonotrode (not shown) and one of the sonotrode opposite

Abutment, which can be designed as a per se known anvil (not shown). The sonotrode is against a contact surface 9a of the contact plate 7 in

Direction of the connecting portion 8 pressed, the Contact surface 9a of the connecting portion 8 and the contact part 4 and the welding section 6 points away. The strand 2 initially has a round cross-section and is flattened or pushed flat by pressing against each other, as can be seen in FIG.

The ultrasonic welding finally takes place by means of the sonotrode - in cooperation with the anvil - in a conventional manner. In this case, the pressing against each other and the ultrasonic welding can take place successively and / or simultaneously. In any case, the contact plate 7 protects a topmost layer of the individual wires 3 from direct contact with the sonotrode, in particular from the profile of the working surface of the sonotrode. The uppermost layer in this case is the layer of individual wires 3, whose individual wires 3 lie completely outside in the strand 2 and are in direct contact with the contact plate 7.

Expensive experiments have surprisingly shown that there is a relative movement between the contact plate 7 and the individual wires 3 of the uppermost layer, which is completely analogous to the relative movement of the individual wires 3 to each other during ultrasonic welding without contact plates 7 according to the prior art. As a result, the contact plate 7 transmits the energy introduced by means of the sonotrode to the

Single wires 3 of the strand 2 and ensures a friction welding, as occurs in conventional ultrasonic welding safely. That the individual wires 3 are welded together and with the contact part 4 and the contact plate 7.

At the same time the contact plate 7 causes a particularly uniform distribution of the friction energy on the individual wires 3, in particular on the uppermost layer of the individual wires 3. This causes a particularly uniform welding all

Single wires 3 and prevents unacceptable deformation of the individual wires 3. It can only a uniform deformation the individual wires 3 occur, but for the uppermost layer fails completely analogous to the bottom layer, which is referred to as the lowest layer that layer of individual wires 3, the individual wires 3 in the strand 2 are completely outside and in

are in direct contact with the contact part 4. The mechanical stability and strength of the individual wires 3 is thus preserved, so that all individual wires 3 in full to the

Current carrying capacity of the stranded conductor 1 can contribute. The welded individual wires 3 all have substantially the same mechanical strength.

By pressing against each other, the contact plate 7 is positively connected to the sonotrode. To one

Relative movement between the contact plate 7 and the

Sonotrode to be able to exclude as completely as possible, a positive connection is additionally generated. An undesirable

 Welding of the contact surface 9a of the contact plate 7 with the sonotrode can thus be excluded. The generation of the additional positive connection is done by the sonotrode has a profile having work surface, with which it is pressed against the contact surface 9 a of the contact plate 7, the sonotrode so strong against the

Contact plate 7 is pressed, that in the contact surface 9a a profile corresponding counter-profile 10a is embossed. This counter-profile 10a can be seen in FIG. 1 and, in the exemplary embodiment shown, essentially consists of grooves which are embossed in the contact surface 9a of the contact plate 7.

By pressing against each other, the contact part 4 is connected in a force-fitting manner to the abutment or the anvil in a completely analogous manner to the above. To a relative movement between the contact part 4 and the anvil as completely as possible

To be able to exclude, a positive connection is additionally generated. An undesirable welding of the contact part 4 with the anvil can thus be excluded. The production the additional positive connection is done by the anvil having a profile having work surface, with which it is pressed against a contact surface 9b of the contact part 4, wherein the anvil is pressed so strongly against the contact part 4 that in the contact surface 9b of the contact part 4 a the Profile corresponding counter-profile 10b is embossed. This counter profile 10b can be seen in Fig. 2 and consists in

illustrated embodiment essentially of grooves that are embossed in the contact surface 9b of the contact part 4. As can be clearly seen in particular in FIG. 3, this shows

 Contact pad 7 in the illustrated embodiment in a longitudinal direction 14 along a longitudinal axis 13 of the

Contact tile 7 seen in an end area one

Outlet zone 11 on. In this outlet zone 11, the

no covered section 12 is found

Ultrasonic welding and in the illustrated

Embodiment also no pressing against each other instead.

Therefore, in the region of the outlet zone 11 on the contact surfaces 9a, 9b and virtually no counter-profile 10a, 10b recognizable, see. Fig. 1 and Fig. 2. Seen in the longitudinal direction 14 is in front of the outlet zone 11, a welding section 15 of the

Contact plate 7 is arranged, in which the

Ultrasonic welding and pressing against each other

take place anyway. In the outlet zone 11 individual wires 3 in the

illustrated embodiment, neither by heat, which is produced during welding, nor by deformation, as they can occur when pressing against each other charged. It is thus guaranteed that the individual wires 3 in the outlet zone 11 have optimum mechanical properties in order to withstand mechanical stresses such as e.g. can be caused by vibration, record and compared to the individual wires 3 in the

Welding section 15 of the contact plate 7 - more precisely:

opposite those sections of the individual wires 3, which in Welding portion 15 of the contact plate 7 are arranged and welded - buffers or to be able to dampen. By this buffer or damping function, the outlet zone 11 thus contributes significantly to the permanent guarantee of the full

Functionality, in particular current carrying capacity, of a system comprising stranded conductor 1, contact part 4 and contact plate 7 in the welded state at.

LIST OF REFERENCE NUMBERS

 Stranded conductor

 braid

 single wire

 contact part

 Degraded section of the stranded conductor

 Welding section of the contact part

 contact plates

 Connecting portion of the stripped portion, 9b contact surface

a, 10b counter profile

 run-off area

 Sheathed section of the stranded conductor

 Longitudinal axis of the contact plate

 longitudinal direction

 Welding section of the contact plate

 coat

Claims

Method for ultrasonically welding a stranded conductor (1) to a contact part (4), wherein a stripped section (5) of the stranded conductor (1) is provided with at least one stranded wire (2), which has several, preferably twisted,  Having individual wires (3), is arranged on a welding portion (6) of the contact part (4), characterized  characterized in that the method comprises the following steps:  - placing a contact plate (7) on the  stripped section (5) such that a  Connecting portion (8) of the stripped portion (5) between the contact plate (7) and the welding portion (6) is arranged;  - Pressing against each other at least one sonotrode and at least one of the at least one sonotrode  opposite abutment, wherein the sonotrode is pressed against the contact plate (7) and / or against the contact part (4) in the direction of the connecting portion (8);  - Ultrasonic welding by means of at least one sonotrode. A method according to claim 1, characterized in that the at least one sonotrode comprises a profile having work surface with which the sonotrode is pressed against a contact surface (9a, 9b) of the contact plate (7) and / or the contact part (4), wherein the Sonotrode so strongly against the contact plate (7) and / or the  Contact part (4) is pressed, that in the contact surface (9a, 9b) a profile corresponding counter-profile (10a, 10b) is embossed. 3. The method according to any one of claims 1 to 2, characterized characterized in that the at least one abutment comprises a profile having work surface with which the abutment against a contact surface (9b, 9a) of the Contact part (4) and / or the contact plate (7) is pressed, wherein the abutment is so strong against the contact part (4) and / or the contact plate (7) pressed that in the contact surface (9b, 9a) corresponding to the profile Counter profile (10b, 10a) is embossed. Method according to one of claims 1 to 3, characterized in that the individual wires (3) are made of a metal and that the contact plate (7) is made of the same metal or an alloy of the same metal. Method according to one of claims 1 to 4, characterized in that the contact plate (7) has a thickness which is in the range of 1 to 3 times a diameter of the individual wires (3). Method according to one of claims 1 to 5, characterized in that seen in a longitudinal direction (14) along a longitudinal axis (13) of the contact plate (7), the contact plate (7) in an end region of a Run-out zone (11), the at  Ultrasonic welding preferably a coated portion (12) of the stranded conductor (1) faces, wherein the ultrasonic welding, and preferably also the pressing against each other, viewed in the longitudinal direction (14) arranged only in a front of the outlet zone (11) Welding section (15) of the contact plate (7) takes place. Method according to one of claims 1 to 6, characterized in that the ultrasonic welding is performed by means of exactly one sonotrode, wherein the sonotrode is pressed against the contact plate (7). 8. System for carrying out a method according to one of claims 1 to 7, the system comprising a stranded conductor (1) with at least one stranded wire (2), which, a plurality of, preferably twisted, individual wires (3), wherein the stranded conductor (1) a stripped portion (5), the system further comprising a contact part (4) with a welding portion (6) on which the stripped portion (5) can be arranged, and a contact plate (7), wherein the system is designed such that the  Contact plate (7) during the procedure on the stripped portion (5) can be arranged to  Ultrasonic welding a connecting portion (8) of the stripped portion (5) between itself and the  Welding section (6) record.