METHOD FOR MANUFACTURING A MOTOR VEHICLE COMPONENT

Description

[0001] The invention relates to a method for producing a welded motor vehicle component.

[0002] Welding is a design-defining manufacturing process for welded components and one of the most important and widely used joining processes, particularly in automotive engineering. Welding is the permanent, material-to-material joining of components using heat and pressure, with or without filler metals. In joint welding, the parts are joined to form the welded component by weld seams at the welded joint. Several welded components form a welded assembly, and several welded assemblies form a welded structure.

[0003] Welding joins components or component sections together in such a way that they can meet the requirements placed on them over their expected service life. To achieve this, the welded joints must meet appropriate quality criteria and characteristics. These are closely linked to the specific component requirements in use. Adequate quality can be expected if irregularities in the weld seam that occur during or after welding can be tolerated for the use of the welded component.

[0004] The weld joint is the area where the welded parts are joined. At the weld joint, the weld design and position have a decisive influence on the functional parameters of the weld, such as penetration. The penetration depth is the distance between the surface of the base material molten by welding and the original surface of the base material, i.e., the depth of the molten zone in the base material.

[0005] The penetration depth is closely related to the joint strength. Weld strength and weld quality are particularly important for automotive components that are subject to high levels of stress during operation.

[0006] An example of a welding joint type and joining method not optimized according to the invention is "flare-bevel-groove welding", as disclosed, for example, in "Arc weld joints Archives - AHSS Guidelines" (URL: https: / / web.archive.org / web / 20220629010452 / https: / / ahssinsights.org / tag / arc-weld-joints / ).

[0007] Based on the prior art, the invention is based on the object of providing a method for producing a welded motor vehicle component with an improved welding result.

[0008] The object is achieved by a method according to claim 1.

[0009] Advantageous further developments and embodiments of the method according to the invention are the subject of the dependent claims.

[0010] A motor vehicle component manufactured according to the method according to the invention comprises a first component and a second component. The two components are made of steel and are connected by at least one weld seam. The first component has a wall with a wall thickness, and the second component has a wall with a wall thickness. The first component and the second component each have a joining surface. The two components are arranged at an angle to one another and are connected by a weld seam at the facing joining surfaces.

[0011] The joining surface at the end section of the first component has a bevel produced without machining.

[0012] The end section of the first component receives seam preparation optimized for welding. The joining surface is extended by the bevel section. The bevel in the joining surface of the end section gives the joining gap between the joining surface of the first component and the joining surface on the second component a V-shaped configuration. The joining gap between the end section of the first component and the second component has a V-shaped configuration. The bevel and the V-shaped joining gap result in very good penetration in the first component. Penetration is the depth of the molten zone in the base material. The invention improves penetration, particularly in the first component. A component-optimized and process-improved penetration is created in the first component without burn-through occurring in the thinner wall of the second component.

[0013] The invention creates a motor vehicle component with a longer service life without increasing the component's weight. The welded joint between the two components is highly stable and exhibits optimized static and, in particular, dynamic load behavior.

[0014] A motor vehicle component manufactured according to the invention is, in particular, a chassis component such as an axle, in particular a twist-beam axle. In particular, it is a twist-beam axle with a first component in the form of a torsion profile and second components in the form of side arms or trailing arms.

[0015] Motor vehicle components of the type produced according to the invention can be all welded constructions in which at least two components with different wall thicknesses are connected by a welded joint, in particular with a T-, L- or X-joint.

[0016] The wall of the first component and the wall of the second component can have the same wall thickness. The wall thicknesses of the first component and the second component can also differ from one another. The invention is particularly advantageous for motor vehicle components in which the first component has a wall with a wall thickness that is greater than the wall thickness of a wall of the second component. Furthermore, it is possible for the first component to have a wall with a wall thickness that is smaller than the wall thickness of the wall of the second component.

[0017] Particularly in the case of welded automotive components made of components with different wall thicknesses, it has been shown that, due to the difference in wall thickness, it is difficult to achieve a high weld penetration into the thicker component, i.e., the component with the greater wall thickness, without causing burn-through in the component with the thinner wall thickness. This lower penetration can reduce the service life of the welded automotive component.

[0018] The bevel and the V-shaped joint gap ensure a high penetration in the first component, i.e. the component with the thicker or stronger wall.

[0019] The invention reliably ensures a penetration of 2% to 10% with a flank penetration of 70% to 90%. In particular, the invention enables a penetration of up to 30% to be reliably achieved. Practical tests suggest even higher penetration values, so that penetration can be increased to more than 50%.

[0020] The chamfer provided by the invention allows filler metal to be pushed between the components in the joint gap during welding, so that the root of the weld seam is moved further or deeper into the joint gap. This results in significantly higher penetration.

[0021] The bevel can extend along the entire joint edge of a motor vehicle component. In particular, the bevel is provided in the areas of the joint edge where the greatest loads from external forces occur. In the torsion profile of a twist-beam axle, the bevel is provided in particular at the joining surfaces of the legs of the torsion profile. In the case of a torsion profile with a U- or V-shaped cross-section, the bevel is arranged on the inside of the torsion profile along the legs.

[0022] The bevel can also be provided only over a partial section of the length of the joining surface at the end section of the first component. In particular, the bevel is formed starting from a free end of the wall of the first component over a length of approximately 30% to 75%, in particular approximately 50%, of the length of the wall of the first component. In the case of a torsion profile with a U- or V-shaped cross-section, the bevel can be arranged on the inside of the cross-section on the inside of the torsion profile on the legs. Furthermore, the bevel can be arranged on the outside of the cross-section on the outside of the torsion profile along the legs.

[0023] The tangential length of the bevel is measured in the cross-section of the torsion profile in the direction of the circumference of the torsion profile and can extend over the entire circumferential length of the end face of the torsion profile. However, the tangential length of the bevel can also extend only over the length of one leg or be provided on a partial section of the length of one leg of a torsion profile.

[0024] The slope runs at an angle to the longitudinal axis of the wall of the first component. The angle is preferably in a range between 25° and 60°. In practice, an angle in the range of 30° to 45° is considered particularly advantageous.

[0025] The joining surface of the first end section preferably has a frontal abutment surface. The abutment surface is located at the front end of the end section. The abutment surface runs essentially perpendicular to the longitudinal axis of the wall of the torsion profile. The abutment surface ensures that the first component butts against the second component.

[0026] One aspect of the invention provides that the abutting surface has a width measured at right angles to the longitudinal axis of the wall of the first component, which is greater than the wall thickness of the wall of the first component.

[0027] The bevel of the joining surface runs into the front face of the end section. The butt surface adjoins the bevel.

[0028] According to the invention, the bevel of the joining surface at the end section of the first component is created without cutting. For this purpose, a controlled plastic deformation is performed at the end section of the first component. The end section is brought into the desired shape by applying an external force. This is achieved, in particular, by bending or shear forming.

[0029] The method according to the invention for producing a welded motor vehicle component comprising at least two steel components with different wall thicknesses, arranged at an angle to each other and connected by a weld seam, comprises the following steps: Manufacturing a first component with a joining surface which has a bevel and an abutting surface, for which purpose a starting blank is provided which has a wall with a wall thickness and an end section of the starting blank is formed and a bevel is formed at the end section and the end section is trimmed at the end and an abutting surface is created at the end section; Providing a second component which has a wall with a wall thickness and the second component has a joining surface; Positioning the first component and the second component at an angle relative to one another such that the joining surface of the first component and the joining surface of the second component face one another; Materially joining the first component and the second component by means of a weld seam on the joining surfaces.

[0030] In particular, the end section is laterally shifted, bent, or stamped during forming. As already explained above, this is achieved, in particular, by bending or shear forming.

[0031] To create the bevel at the end section, the end section of the original blank can first be formed into an S shape. The end section is then trimmed, and an end piece is separated from the free end of the end section. The trimming is performed at right angles to the longitudinal axis of the original blank or the wall of the original blank. During the trimming process, a slight chamfer is created, particularly on the side of the cutting tool's counterholder. Consequently, the trimming line is not straight but has a slightly angled bevel or surface at the end of the trimming line.

[0032] The initial blank can be subjected to further forming before or after the forming and trimming of the end section. During this forming step, the initial blank, at least in some areas, particularly along its length, acquires a cross-sectional configuration similar to that of the first component.

[0033] Furthermore, it is provided that the end-side trimming of the end section takes place at an angle transversely, in particular substantially at right angles to the longitudinal axis of the wall of the output board.

[0034] Within the scope of the invention, it is particularly provided that the first component and the second component have different wall thicknesses. In particular, the wall thickness of the second component is, at least in some regions, less than the wall thickness of the first component in the region of the joint. Accordingly, a second component is provided which has a wall with a wall thickness that differs from the wall thickness of the first component.

[0035] The invention is described in more detail below with reference to the drawings. They show: Figure 1a) to d) technically schematically illustrates the procedure for manufacturing a first component with a joining surface which has a bevel and a butt surface; Figure 2a) a section of the wall of a first component and a section of the wall of a second component before the welding; Figure 2b) the components according to the representation of the Figure 2a) after welding; Figure 3 shows a perspective view of a twist beam axle; Figure 4 shows a view of the front side of the end section of a torsion profile of a twist beam axle; and Figure 5 shows a view of the front side of the end section of a further embodiment of a torsion profile.

[0036] Based on the Figures 1a ) to d) the forming process for producing a first component 1 of a motor vehicle component 2 is explained. The motor vehicle component 2 is in the Figure 2b ) is shown.

[0037] The Figure 1a ) shows an output board 3. The output board 3 has a wall 4 with a wall thickness t1.

[0038] An end section 5 of the initial blank 3 is formed without cutting. The end section 5 is plastically deformed and configured in an S-shape. This creates a leg 6 with a bevel 7 and an end piece 8 running parallel to the longitudinal axis L of the wall 4 of the initial blank 3. This is shown in the illustration of the Figure 1b ). The end piece 8 is shifted laterally parallel to the longitudinal axis L of the wall 4.

[0039] The Figure 1c ) illustrates the trimming operation at end section 5. An end trim is performed at end section 5. The cutting tool is identified by reference numeral 9. The trimming is performed at an angle perpendicular to the longitudinal axis L of wall 4 of the output board 3 along trim line B.

[0040] The trimming operation takes place in the area of ​​leg 6 with bevel 7. During trimming, end piece 8 is removed. A butt joint 10 is created on the end face of end section 5, running perpendicular to the longitudinal axis L.

[0041] The Figure 1d ) shows the finished trimmed first component 1.

[0042] The abutting surface 10 has a width b measured at right angles to the longitudinal axis L of the wall 4 of the first component 1, which is greater than the wall thickness t1 of the wall 4 of the first component 1. The ratio of the wall thickness t1 of the wall 4 of the first component 1 to the width b of the abutting surface 10 is between 1:1.1 and 1:1.5.

[0043] The bevel 7 has an axial length I. The axial length I of the bevel 7 is measured in the direction of the longitudinal axis L of the wall 4 of the torsion profile 1. The axial length I is measured in the area of ​​the later joint connection. The bevel 7 runs at an angle β of 25° to 60°, in particular of 30° to 45°, to the longitudinal axis L of the wall 4 of the first component 1. The ratio of the axial length I of the bevel 7 to the wall thickness t1 of the wall of the first component 1 is between 1:1 and 1:5. The bevel 7 is located on the side of the end section 5 of the first component, which forms the acute angle β with the second component 11.

[0044] To manufacture the motor vehicle component, a second component 11 made of steel is provided. The second component 11 has a wall 12 with a wall thickness t2. The wall thickness t1 of the wall 4 of the first component 1 is greater than the wall thickness t2 of the wall 12 of the second component 11.

[0045] The first component 1 has a joining surface 13 at the end section 5. The joining surface 13 includes the bevel 7 and the end-face abutment surface 10.

[0046] The second component 11 also has a joining surface 14.

[0047] The first component 1 and the second component 11 are joined by a welded joint. To create the welded joint, the first component 1 and the second component 11 are positioned relative to each other. This is shown in the illustration of the Figure 2a ). The first component 1 and the second component 11 are arranged at an angle α to each other; in particular, the first component 1 butts against the second component 11 at a right angle α with a T-joint.

[0048] The joining surface 13 of the first component 1 and the joining surface 14 of the second component 11 face each other. The abutting surface 10 runs at a right angle to the longitudinal axis L of the wall 4 of the first component 1. The abutting surface 10 is oriented parallel to the joining surface 14 of the second component 11. A V-shaped joining gap 15 is formed between the joining surface 13 of the first component 1 and the joining surface 14 of the second component 11. At the deepest point of the V-shaped joining gap 15, there is a gap section 16 running parallel between the abutting surface 10 and the joining surface 14 of the second component 11. The bevel 7 runs at an acute angle to the end face 17. The bevel 7 ends at the end face 17. The abutting surface 10 adjoins the bevel 7 at an obtuse angle.

[0049] The material-to-material joining connection is made via a weld seam 18, as shown in the Figure 2b). Due to the bevel 7 and the V-shaped joint gap 15, the weld seam 18 is efficient, whereby a high penetration in the first component 1 is achieved.

[0050] Through the seam preparation and the formation of the bevel 7 in the joining surface 13 on the first component 1, as well as the V-shaped configuration of the joining gap 15, a welded joint is created between the first component 1 and the second component 11 with a quality and service life that meets the requirements. The penetration of the weld seam 18 on the first component 1 can be significantly increased without causing burn-through on the second component 11. The weld seam 18 meets the highest strength requirements, thereby extending the overall service life of the motor vehicle component 2 without increasing its overall weight.

[0051] The motor vehicle component 2 is, in particular, a twist-beam axle. In the twist-beam axle, a first component 1 in the form of a torsion profile is welded at each end to a second component 11 in the form of a side arm.

[0052] The Figure 3 shows a motor vehicle component 2 in the form of a twist-beam axle with a first component 1, which is the torsion profile, and second components 11, each of which is a side arm of the twist-beam axle. The torsion profile has a wall 4 with a wall thickness t1. Each side arm has a wall 12 with a wall thickness t2. The wall thickness t1 of the wall 4 of the torsion profile can be greater than the wall thickness t2 of a side arm. Reference is made to the explanations regarding the illustrations in the Figures 1 and 2The torsion profile has a U-shaped cross-section with two side legs 19 connected by an apex section 20. The end section 5 of the torsion profile abuts the wall 12 of a side arm. The joining surface 13 at the end section 5 of the torsion profile is adapted to the outer contour of the wall 12 of the side arm.

[0053] Arrow P1 schematically illustrates the length of a side leg 19, with which the end section 5 of the first component 1 or the torsion profile abuts the outer circumference of a side arm. This length is approximately 180° + / - 15° relative to the circumference of the side arm, which has a round cross-section.

[0054] The arrow P2 indicates the length of a longitudinal section 21 of the first component 1 or of a side leg 19, in which the bevel 7 is provided on the inside of the side leg 19. The bevel 7 is provided in the lower longitudinal section 21 of the side leg 19. In particular, the bevel 7 extends over two-thirds, in particular approximately half, of the length of a side leg 19. Relative to the cross-section of a side arm, the bevel 7 extends over a circumferential section of approximately 90° + / - 15°. The bevel 7 is provided in the lower longitudinal section 21 of a side leg 19, starting from the free leg end.

[0055] The Figure 4shows an end view of the joining surface 13 at an end section 5 of a first component 1 in the form of a torsion profile. The torsion profile has a wall 4 with a wall thickness t1. A bevel 7 produced according to the invention is provided in the joining surface 13 at the end section 5 of the torsion profile. The bevel 7 runs on the inside of the side legs 19 of the torsion profile.

[0056] The bevel 7 is provided in the lower longitudinal section 21 of the side leg 19, extending from the free leg end. The tangential length of the longitudinal section 21 is indicated by the arrow P2. In the illustrated embodiment, the bevel 7 extends approximately over half the length of a side leg 19.

[0057] The Figure 5 shows a front view of the joining surface 13 in an alternative embodiment at the end section 5 of a torsion profile 1. Unlike the embodiment according to the Figure 4Here, the bevel 7 is arranged on the outside of the side legs 19 of the torsion profile. As in the other embodiments, the bevel 7 is produced by machining. The bevel 7 extends in a lower longitudinal section 21 of each side leg 19, starting from the free leg end. Otherwise, the embodiment corresponds to that of Figure 4 and the corresponding description. Reference symbol:

[0058] 1 - first component 2 - motor vehicle component 3 - output board 4 - wall 5 - end section 6 - leg 7 - bevel 8 - end piece 9 - cutting tool 10 - butt surface 11 - second component 12 - wall 13 - joining surface 14 - joining surface 15 - joining gap 16 - gap section 17 - end face 18 - weld seam 19 - side leg 20 - apex section 21 - length section 19 b -Width B -Cutting line L -Longitudinal axis t1 -Wall thickness t2 -Wall thickness α-Angle β -Angle I -Length v. 7

Claims

1. A method for the production of a welded motor vehicle component, which has at least two components (1, 11) made of steel with different wall thicknesses (t1, t2), which are arranged at an angle (α) to one another and connected by a weld seam (18), having the following steps: - manufacturing a first component (1) with a joining surface (13) which has a bevel (7) and an abutment surface (10), for which purpose - a starting blank (3) is provided which has a wall (4) with a wall thickness (t1) and - an end section (5) of the starting blank (3) is reshaped and a bevel (7) is designed on the end section (5) and - the end section (5) is trimmed at the end, and an abutment surface (10) is created on the front side of the end section (5); - providing a second component (11) which has a wall (12) with a wall thickness (t2) and the second component (11) has a joining surface (14); - positioning the first component (1) and the second component (11) at an angle (α) relative to one another, such that the joining surface (13) of the first component (1) and the joining surface (14) of the second component (11) face one another; - joining the first component (1) and the second component (11) in a materially-bonded manner by way of a weld seam (18) on the joining surfaces (13, 14).

2. The method according to claim 1, characterised in that the end section (5) is laterally displaced, bent or embossed during reshaping.

3. The method according to claim 1 or 2, characterised in that the starting blank (3) is subjected to further reshaping before or after the reshaping and trimming of the end section (5), wherein a cross-sectional configuration of the first component (1) is formed at least in regions.

4. The method according to any one of claims 1 to 3, characterised in that the trimming of the end section (5) at the end takes place at an angle transversely, in particular substantially at right angles, to the longitudinal axis (L) of the wall (4) of the starting blank (3).

5. The method according to any one of claims 1 to 4, characterised in that a second component (11) is provided which has a wall (12) with a wall thickness (t2), wherein the wall thickness (t2) of the wall (12) of the component (11) is different from the wall thickness (t1) of the wall (4) of the first component (1) and in particular wherein the wall thickness (t2) of the wall (12) of the second component (11) is smaller than the wall thickness (t1) of the wall (4) of the first component (1).