DE102023004143B4 - Method for joining components by laser welding using a laser welding device - Google Patents

Abstract

Method for joining components (14, 16) by laser welding using a laser welding device (12), in which a first component (14) and a second component (16) are arranged along respective longitudinal sides (18, 20) and are welded by laser welding in the region of respective end faces (22, 24), characterized in that a melt (32) produced by the welding is at least partially deformed in the region of the respective end faces (22, 24) by means of a gas stream (G) in that the gas stream (G) is directed at least partially on the outer circumference side onto the melt (32) and at an angle relative to the longitudinal direction of extension of the components (14, 16) onto the melt (32), wherein the gas stream (G) is directed substantially axially to the force of gravity (F) from an annular gas nozzle (26) having a plurality of inner circumference outlet openings (36) onto the melt (32).

Description

The invention relates to a method for joining components by laser welding using a laser welding device according to the preamble of patent claim 1.

The DE 10 2019 103 668 A1 discloses a method for joining copper hairpins, comprising providing at least two ends of the copper hairpins to be joined together and joining the copper hairpins to be joined by laser beam welding with a processing beam.

In the DE 10 2022 106 787 B3 A method for producing a winding for an electrical machine is disclosed, in which two conductor ends are electrically contacted at a contact point. For this purpose, a material reservoir is pushed onto the contact point, which surrounds the two conductor ends in a ring-like manner and consists of an insulating material. This material melts when the contact point is created by welding, forming an insulating structure that insulates the conductor ends in the area of the contact point from their surroundings.

From the CN 1 11 151 881 A A laser welding device for a specially shaped cylindrical component is known, which comprises a coaxial gas nozzle, a lateral gas nozzle, and a control module. The coaxial gas nozzle is arranged on a welding head of the laser welding machine and serves to spray shielding gas around the part of the specially shaped cylindrical component to be welded. The lateral gas nozzle is arranged on one side of the welding head and serves to spray the shielding gas with a specific force onto the part to be welded. The control module is used to adjust the strength of the gas flow at both the coaxial gas nozzle and the lateral gas nozzle. The strength settings depend on a preset movement path as well as the gravity and surface tension of molten pools at different welding positions. This ensures the stability of the molten pool structures and reduces the occurrence of perforation phenomena.

The object of the invention is to provide a possibility by which a joint between two components can be produced better and more efficiently during welding.

This object is achieved by means of a method having the features of patent claim 1. Advantageous configurations of a laser welding device are to be regarded as advantageous embodiments of the method according to the invention, wherein the means of the laser welding device are used to carry out the method steps. Furthermore, advantageous developments of the invention are described by the dependent patent claims, the following description, and the figures.

The invention relates to a method for joining components by laser welding using a laser welding device, in which a first component and a second component are arranged along respective longitudinal sides and welded by laser welding in the region of respective end faces. This method thus provides an extremely effective method for welding components, with a particular focus on connecting the two components that are arranged along their longitudinal sides, with the welding taking place in the region of their end faces. The components used in this method are often referred to as hairpins, which in particular have an elongated shape.

To achieve the object of the invention, it is provided that a melt generated by welding is at least partially deformed in the region of the respective end faces by means of a gas stream. During laser welding, a melt is created on each of the components to be joined, which are then fused into a single melt. This single melt can exhibit various problems, such as uneven distribution, incorrect alignment, or inadequate shaping. The melt is therefore specifically shaped and cooled to create a particularly good joint. This process ensures that the single melt has the most predetermined shape and strength possible after welding, resulting in a reliable and stable connection between the components.

The invention thus provides for the use of a targeted gas flow, for example an air flow or a protective gas flow, in particular argon, by means of which a targeted influence on the cooling melt can be carried out. For this purpose, a fan and at least one gas channel are provided, for example, to specifically control the gas flow. The control allows the direction of the gas flow and its intensity to be adjusted, for example, by means of an arranged control device.

An example of the application of this process could be to deliberately direct the total melt flowing in a certain direction in the opposite direction by a gas stream. This prevents the total melt flowing along one side of the components. Instead, it remains on the front sides of the components and cools. This allows the melt to form into a round melt droplet, which forms the joint between the components.

This targeted cooling and shaping of the melt using a controlled gas flow allows for the joint to be tailored to meet the desired quality and strength requirements. This process can be used in various applications to achieve high-quality and reliable welds of components.

According to the invention, the gas flow is directed onto the outer circumference of the melt. This ensures that a gas flow acts on the entire melt from all sides to form the roundest possible melt droplet. To implement this technically, the laser welding device is equipped with a targeted gas flow mechanism that can be directed onto the melt from the outside. This mechanism allows the gas flow to be controlled so that it surrounds and acts on the melt to create the desired droplet shape and enable a predetermined cooling.

According to the invention, the gas flow is directed onto the melt along its outer circumference and at an angle relative to the longitudinal extension of the components. This allows for flexible control of the gas flow direction. The gas flow can thus be directed within a range of 360 degrees around the circumference of the melt, or obliquely from above or obliquely from below with respect to the longitudinal alignment of the arranged components. An oblique gas flow from above could tend to flatten the melt droplet, while an oblique gas flow from below would tend to raise it. The intensity of the gas flow can also be adjusted to control the desired shape of the melt. This enables extremely fine control over the melting process.

In another advantageous embodiment of the invention, the laser beam for laser welding is directed substantially axially relative to gravity. Such an orientation not only allows the flow to be directed in a lateral circumferential direction, but also utilizes gravity to influence the molten droplet in a specific direction. For example, the laser beam could be directed from above, while simultaneously the gas flow is directed from below upwards to counteract this force of gravity. This combination of factors allows further control of the molten shape and position to achieve a desired joint or weld.

In another advantageous embodiment of the invention, the laser beam for laser welding is directed essentially axially and against gravity. This orientation also utilizes gravity, but this time the laser beam is directed from below onto the downward-facing end faces of the components or hairpins. This arrangement allows for effective control of the melting zone and the directing of the melt toward the components to enable a predetermined weld.

According to the invention, the gas flow is directed toward the melt substantially axially relative to gravity. This arrangement allows the lower laser welding device to direct the laser beam upward, causing the entire melt to drip in the direction of gravity. The gas flow directed toward the outer periphery from the outside counteracts this flow to prevent the melt from dripping downward. This provides effective control over the melt position and shape to achieve a specified weld.

A laser welding device for joining components by laser welding, by means of which a first component and a second component can be arranged along respective longitudinal sides and welded together by laser welding in the region of respective end faces, can be used to carry out the method according to the invention.

It is intended that a melt generated by welding can be at least partially deformed in the region of the respective end faces by means of a gas flow from a gas nozzle. The laser welding device comprises, for example, a laser source, a clamping device for holding the components, a gas flow mechanism with a gas nozzle, and an alignment device for the laser radiation and the gas flow, for example, by means of an integrated control device or an electronic computing device.

According to the invention, the gas nozzle is ring-shaped and arranged around the outer circumference of the melt. This gas nozzle is particularly designed to expel a uniform but also variable gas stream that surrounds the entire melt and acts on it from the outside. This arrangement enables predetermined control of the melt shape and position to ensure a particularly good or optimal joint between the components.

According to the invention, the annular gas nozzle is provided with a plurality of outlet openings along its inner circumference. These outlet openings are designed to direct the generated gas flow evenly onto the melt and enable control over its deformation and cooling. This arrangement contributes to ensuring high-quality welding of the components.

Alternatively, the annular gas nozzle can be provided with a continuous outlet opening on its inner circumference. This continuous outlet opening enables a uniform and continuous gas flow that surrounds the entire melt and facilitates uniform deformation and cooling.

Additionally, in these designs, the intensity of the gas flow is also variably adjustable. This allows the strength of the gas flow to be adjusted as needed to control the desired melt deformation and cooling.

In summary, the invention proposes that melt forming during laser welding of components or hairpins be carried out by a gas flow from a directed gas nozzle during the welding process while the melt is still liquid. A nozzle for directing the gas flow is arranged around the ends of the hairpins and is supplied with air/gas. The hairpins can optionally be held by a clamping device during welding, whereby the gas outlet nozzle can be part of the clamping device or arranged independently. The nozzle can be one-piece and arranged on one side or can be a curved nozzle that at least partially surrounds the hairpin ends. It can also be circular or annular and completely surround the ends or the welding area. For longer nozzles, the nozzle opening can be continuous or consist of a plurality of individual nozzles that together generate the desired gas flow for shaping the melt.

Shaping can occur during or after laser irradiation, although the cooling effect of the gas flow must be taken into account when setting the laser intensity and duration. If the nozzle is annular and moves the melt away from the hairpin at the ends before welding, it must be moved over the weld and any weld bead after welding, so that the required radius of the annular nozzle is taken into account. The nozzle can be static and always flow in the same direction, or it can be movable and adapt to the shape of the melt. This requires an actuator for movement and a control and monitoring device for positioning and flow control of the nozzle. In conjunction with a clamping device or a general movement device, the nozzle is positioned and oriented according to the ends of the hairpins.

Further advantages, features, and details of the invention will become apparent from the following description of preferred embodiments and from the drawings. The features and combinations of features mentioned above in the description, as well as the features and combinations of features mentioned below in the description of the figures and/or shown alone in the figures, can be used not only in the respective specified combinations, but also in other combinations or on their own, without departing from the scope of the invention.

• 1 eine Perspektivansicht einer möglichen Ausgestaltung einer Laserschweißvorrichtung zum Fügen von Bauteilen mittels einer Gasdüse und Laserschweißen in Hochrichtung von oben;
• 2 einen Querschnitt der aneinander angeordneten Bauteile mit einer geformten Schmelze gemäß 1;
• 3 eine weitere Perspektivansicht einer weiteren möglichen Ausgestaltung einer Laserschweißvorrichtung zum Fügen von Bauteilen mittels einer Gasdüse und Laserschweißen in lateraler Anordnung;
• 4 einen Querschnitt der aneinander angeordneten Bauteile mit einer geformten Schmelze gemäß 3;
• 5 eine weitere Perspektivansicht einer weiteren möglichen Ausgestaltung einer Laserschweißvorrichtung zum Fügen von Bauteilen mittels einer Gasdüse und Laserschweißen in Hochrichtung von unten;
• 6 einen Querschnitt der aneinander angeordneten Bauteile mit einer geformten Schmelze gemäß 5;

Showing:

• 1 a perspective view of a possible embodiment of a laser welding device for joining components by means of a gas nozzle and laser welding in the vertical direction from above;
• 2 a cross-section of the components arranged next to each other with a shaped melt according to 1 ;
• 3 a further perspective view of another possible embodiment of a laser welding device for joining components by means of a gas nozzle and laser welding in a lateral arrangement;
• 4 a cross-section of the components arranged next to each other with a shaped melt according to 3 ;
• 5 a further perspective view of another possible embodiment of a laser welding device for joining components by means of a gas nozzle and laser welding in the vertical direction from below;
• 6 a cross-section of the components arranged next to each other with a shaped melt according to 5 ;

In the figures, identical and functionally identical elements are provided with the same reference numerals.

The 1 shows a perspective view of a possible embodiment of a laser welding device 12 for joining components 14, 16 using a gas nozzle 26 and laser welding. A first component 14 and a second component 16, in particular hairpins, are arranged along their respective longitudinal sides 18, 20 and can be welded together by laser welding in the region of their end faces 22, 24.

In this laser welding device 12, a melt 32 is generated during the welding process. In order to at least partially deform the melt 32 in the region of the end faces 22, 24 of the components 14, 16, a gas nozzle 26 is arranged through which a gas flow G is directed.

In this embodiment, the gas nozzle 26 is ring-shaped and surrounds the melt 32 on its outer circumference. This ring-shaped gas nozzle 26 is equipped with a plurality of outlet openings on its inner circumference, which direct the gas flow G specifically onto the melt 32.

A particularly characteristic feature of this laser welding device 12 is that the annular gas nozzle 26 has a continuous outlet opening on the inner circumference, which makes it possible to distribute the gas flow G evenly over the entire circumferential surface of the melt 32.

The laser welding device 12 can optionally be used with a clamping device for securing the components 14, 16 during the welding process. The gas nozzle 26 can be an integral part of the clamping device or arranged separately.

Melt forming by gas flow G can occur during or after laser irradiation. It is important to note that the cooling effect of gas flow G on melt 32 must be considered when adjusting the laser power and duration to achieve the desired melt forming.

The annular gas nozzle 26 can be static in position or designed as a movable nozzle that adapts to the shape of the melt 32. A movement device, controlled by a monitoring and control device, can position the nozzle accordingly to achieve the desired shape of the melt 32. This also requires an actuator to move the gas nozzle 26.

In the 1 1 shows the laser welding device 12, by means of which a method for joining components 14, 16 by laser welding is carried out, in which the first component 14 and the second component 16 are arranged alongside one another along respective longitudinal sides 18, 20 and are welded by laser welding in the region of respective end faces 22, 24. In addition, it is provided that a melt 32 produced by the welding is at least partially deformed in the region of the respective end faces 22, 24 by means of a gas flow G. In this case, the melt 32 produced by the welding is deformed in the region of the end faces 22, 24 by a targeted gas flow G. The gas nozzle 26 of the laser welding device 12 is annular and surrounds the melt 32 on the outer circumference. This annular gas nozzle 26 has a plurality of outlet openings on the inner circumference, which direct the gas flow G on the outer circumference onto the melt 32 in order to enable targeted deformation.

The representation in 1 illustrates how the gas stream G exiting the annular gas nozzle 26 is directed onto the melt 32. The gas stream G can also be angled relative to the longitudinal extension direction of the components 14, 16 to achieve the desired melt formation.

In summary, the 1 a laser welding device 12 with an annular gas nozzle 26, which provides a gas flow G for forming the melt 32 in the region of the end faces 22, 24 of the components 14, 16.

2 shows a cross-section of the components 14, 16 arranged next to one another. It is particularly emphasized how the gas flow G for melt forming is positioned on the outer circumference and is directed at the melt 32 at an angle relative to the longitudinal extension direction of the components 14, 16. This angle is particularly from below, which serves to create an ideal drop of the melt 32.

The components 14 and 16 are connected to each other along their long sides, and the melt 32 in the area of their end faces is specifically processed by the laser beam 34 and the gas flow G. In 2 The oblique positioning of the gas flow G below the components 14, 16 is illustrated to enable the melt 32 to be brought into the desired shape of an ideal drop. 2 thus illustrates the exact orientation and angle of the gas flow G acting on the melt 32 during the laser welding process in order to enable a predetermined shaping and cooling of the melt 32.

3 shows a gas nozzle 26 directed from bottom to top and a lateral irradiation by the laser beam 34 directed from top to bottom onto a horizontal arrangement of the components 14, 16. This utilizes the force of gravity F, which is counteracted by the gas flow G.

In other words, this results in the force of gravity F being utilized to move the melt 32 in an upward direction. The gas stream G exiting the gas nozzle 26 counteracts the force of gravity F and influences the movement of the melt 32.

4 shows a cross section of the 3 shown embodiment to demonstrate the effect of the gas flow G on the melt 32. In other words, the force of gravity F is counteracted. Compared to the vertical z, the gas flow G is directed from bottom to top with the gas nozzle 26 on the outer circumference onto the melt 32, which prevents dripping.

5 shows a gas nozzle 26 oriented obliquely to a horizontal line y and a bottom-up irradiation by the laser beam 34 onto a vertical arrangement of components 14, 16, with the end faces facing downward. This utilizes the force of gravity F, which is partially counteracted by the gas flow G.

In other words, this results in the utilization of gravity F to form the melt 32 into a flattening shape. The gas stream G exiting the gas nozzle 26 partially counteracts gravity F and influences the downward movement of the melt 32.

6 shows a cross section of the 5 shown configuration to demonstrate the effect of the gas flow G on the melt 32. In other words, the force of gravity F is partially counteracted. Due to the oblique angular orientation relative to the horizontal y, the gas flow G is directed obliquely from bottom to top with the gas nozzle 26 on the outer circumference onto the melt 32, which prevents dripping and enables a uniform 360° flow for a round and, in particular, flat shape.

List of reference symbols

12

Laser welding device

14

first component

16

second component

18

long side

20

long side

22

Front sides

24

front side

26

Gas nozzle

32

melt

34

laser beam

36

Exit opening

G

Gas flow

F

gravity

Z

vertical

Y

horizontal

Claims (3)

Method for joining components (14, 16) by laser welding using a laser welding device (12), in which a first component (14) and a second component (16) are arranged along respective longitudinal sides (18, 20) and are welded by laser welding in the region of respective end faces (22, 24), characterized in that a melt (32) produced by the welding is at least partially deformed in the region of the respective end faces (22, 24) by means of a gas flow (G) in that the gas flow (G) is directed at least partially on the outer circumference side onto the melt (32) and at an angle relative to the longitudinal direction of extension of the components (14, 16) onto the melt (32), wherein the gas flow (G) is directed substantially axially to the force of gravity (F) from an annular gas nozzle (26) having a plurality of inner circumference outlet openings (36) onto the melt (32). Procedure according to Claim 1 , characterized in that the gas flow (G) is directed entirely onto the outer circumference of the melt (32). Procedure according to Claim 1 or 2 , characterized in that a laser beam (34) for laser welding is directed substantially axially and against the force of gravity (F).