KR20190109282A - Component assembly with fiber laser welded joint and method for this - Google Patents

Abstract

The present invention relates to a component assembly comprising a first component (10), a second component (20), and a fiber laser weld joint (2) between the first component (10) and the second component (20) for connecting the first component and the second component in a joint gap (6). The fiber laser weld joint (2) comprises at least one first weld seam (3) and a second weld seam (4), and the first weld seam (3) and the second weld seam (4) are arranged directly in parallel and in contact with each other. Therefore, an objective of the present invention is to provide the component assembly including the fiber laser weld joint between two components having a very high strength even under difficult conditions.

Description

Component assembly including fiber laser welded joint and method therefor {COMPONENT ASSEMBLY WITH FIBER LASER WELDED JOINT AND METHOD FOR THIS}

The present invention relates to a component assembly comprising a fiber laser weld joint, an injector comprising said component assembly, in particular a fuel injector and a method of manufacturing a fiber laser weld joint.

In the prior art, welded joints between two parts are known in different forms. In the manufacture of a fuel injector, for example, two parts are connected to each other by a weld joint, ie the inner pawl and the connecting sleeve. In this case, a single weld seam is produced by the disc laser. Due to the ever-increasing environmental standards in internal combustion engines, the injection pressure also increases continuously, especially in diesel and gasoline internal combustion engines. Investigations have shown that under vibration loads as seen in automotive internal combustion engines and due to very high pressures in the range exceeding 800 x 10 ⁵ Pa, seam failures may occur due to overload in previously used weld joints. There is therefore a need to improve these weld joints, especially for injectors to be used at very high pressures.

It is an object of the present invention to provide a part assembly comprising a fiber laser weld joint between two parts having very high strength even under difficult conditions, an injector with the part assembly, and a method of manufacturing the fiber laser weld joint.

The problem is solved by the objects having the features of the independent claims.

The part assembly according to the invention with the features of claim 1 has the advantage that the weld joint between the two parts is severe and has very high strength even in difficult conditions. Particular damage to the seam of the welding seam, in particular due to vibration loads and high pressures, can be prevented, especially when there is a continuous load, such as in an injector in an internal combustion engine of a vehicle. The part assembly includes a first and second part and a fiber laser weld joint between these two parts. The fiber laser welding joint connects the first part with the second part in the joint gap between the parts. The joint gap between the first and second parts is the position where the parts to be connected to each other abut each other. The fiber laser weld joint includes at least one first and second weld seam. At least two weld seams are placed directly next to each other, the weld seams are contacted, and the at least one weld seam lies over the joint gap between the parts to be joined. Since the weld seams are all fiber laser weld seams, there is a feeling of continuous weld seams after completion of the weld seams.

The dependent claims present preferred embodiments of the invention.

More preferably, the first weld seam is partially disposed over the joint gap between the first and second parts. Particularly preferably a second welding seam is arranged over the joint gap between the two parts. It is particularly preferred that the first weld seam and the second weld seam are arranged over the joint gap between the parts. Thereby, a partial overlap of the first and second weld seams is made over the joint gap and preferably this overlap is as small as possible.

More preferably, the first and second parts are provided as closed parts, respectively, and the fiber laser weld joint is also formed so that the circumference is closed. The first and second parts are particularly preferably provided as cylindrical, in particular hollow cylindrical coupling partners.

More preferably, the fiber laser weld joint is formed on the outer circumference of the cylindrical or hollow cylindrical coupling partners.

According to another preferred embodiment of the present invention, in the case of parts with a closed circumference, the start point and the end point of different welding seams are offset from each other in the longitudinal direction or the circumferential direction. This prevents the start and end points of the various weld seams from being at the same height in the circumferential direction.

According to another preferred embodiment of the invention, the fiber laser weld joint is provided such that the penetration of the first and second parts is not complete, in particular given in a range less than 90% of the wall thickness of the parts. The penetration is particularly preferably at most 80% and at least 50% of the wall thickness of the parts.

More preferably the aspect ratio of the weld seams is chosen as large as possible. Aspect ratio is the ratio of the depth of the weld seam in the part to the largest width of the weld seam. The largest width of the weld seam is on the surface of the parts to be joined. The aspect ratio is preferably greater than 5, in particular greater than 8.

According to another preferred embodiment of the present invention, the fiber laser welding joint includes at least one third welding seam. The positioning of the weld seams is such that the second weld seam and the third weld seam are disposed next to and in contact with the first weld seam. The second weld seam is in contact with the first side of the first weld seam and the third weld seam is in contact with the second side of the first weld seam. The first weld seam preferably lies in the middle between the second and third weld seams.

Preferably four weld seams may be provided or more preferably five weld seams may be provided. The layout should be chosen according to the number of weld seams across the joint gap of the parts. In the case of four weld seams, a joint gap is disposed between the two intermediate weld seams and the two outer weld seams each contact the weld seam of one of the two intermediate weld seams. In the case of five weld seams, two additional weld seams are provided, each of which is placed directly over the joint gap of the parts and in contact with each other on both sides of the intermediate weld seam. Thus a single weld seam is felt even when four or five weld seams are provided.

More preferably the widths of the welding seams are each chosen equally. This ensures a defined heat introduction into the parts and all welding seams can be produced by the same fiber laser without having to change the setting of the fiber laser. This ensures that too high heat is not introduced into the two parts to be connected. Preferably the width of the weld seams on the surface of the parts is in the range of 250 to 350 μm, particularly preferably in the range of 260 to 320 μm. Preferably the seam width on the inner end of the weld seam is in the range of 70 to 140 μm, particularly preferably in the range of 80 to 130 μm. Thereby, the welding seam which narrows in a cross section is formed. Thus, the welding seams are contacted or overlapped on the surfaces of the parts, and the welding seams are spaced from each other inside the parts. Thus, heat introduction into the parts to be joined can be intentionally reduced.

In the case of three welding seams, particularly preferably the center of the intermediate welding seam is arranged above the joint between the parts to be joined. More preferably, when the parts with closed outer periphery, for example the parts to be joined, are cylindrical, the starting and ending points of the welding seams are arranged offset from one another in the circumferential direction. The offset is in particular made such that the start and end points are offset by an angle divided by 360 ° by the number of weld seams. For example, when there are three weld seams, the starting points and the end points are arranged offset from each other at an angle of 120 ° along the circumference.

More preferably, if three weld seams are provided, the first distance between the first center line of the first and intermediate weld seams and the second center line of the second weld seams is equal to that of the first and third weld seams. Is equal to the second distance between the third centerline. This achieves a symmetrical arrangement of the second and third weld seams relative to the first weld seam. More preferably the first and / or second distance between the centerlines of the at least three weld seams is in the range from 20 μm to 100 μm, in particular in the range from 40 μm to 80 μm.

More preferably the first and second parts are made of metallic material. More preferably the two coupling partners have wall regions parallel to each other on the joint gap.

The invention also relates to an injector, in particular a fuel injector, comprising a component assembly according to the invention. Particularly preferably the injector is a magnetic injector, the first part is an inner pole of the injector and the second part is a sleeve, in particular a connecting sleeve for hydraulic connection of the injector.

The invention also relates to a method of manufacturing a fiber laser weld joint between a first part and a second part. The method includes positioning the first and second components for joining by welding, manufacturing a first welding seam between the first and second components in the region of the joint gap by a fiber laser, and a fiber laser Manufacturing a second welding seam that lies directly adjacent to the first side of the first welding seam.

More preferably, the method also includes producing a third welding seam. In this case, the weld seams are placed such that the third weld seam is directly adjacent and in contact with the first weld seam on the second side of the first weld seam.

Preferably further a fourth welding seam or more preferably a fifth welding seam is also provided. The weld seams are always set to each other to feel a single seam after the formation of the fiber laser weld joint.

Preferably, when there are three weld seams, first the first weld seam is completely manufactured, and then the second weld seam is completely manufactured, and then preferably the third weld seam is fully manufactured. However, for example, when the first welding seam starts and preferably after a certain time the second welding seam starts and after a further some time the third welding seam starts, the welding seams may be made to overlap in time. It is desirable that three weld seams be manufactured in series because the cost for the fiber laser is significantly reduced.

Preferably, when there are three weld seams, the first weld seam is set directly over the joint gap between the first and second parts. In this case, preferably the center of the first welding seam is set above the joint gap. Preferably, however, it is also possible for the first weld seam to be set slightly offset relative to the joint gap, but to cover the joint gap, and then the center of the other weld seam to be set above the joint gap. In other words, it is also possible for one or two external welding seams to be set first and then an intermediate welding seam to be set in the fiber laser weld joint as well.

More preferably the fiber laser is directed vertically onto the joining point between the first and second parts. Thus, exactly the fiber laser welding seam can be placed along the joining point.

In particular when the first and second parts are closed-circuit parts, in particular cylindrical parts, in particular cylindrical hollow parts, particularly preferably the starting and / or end points of at least three welding seams are arranged so as to be offset in the direction of the welding seam. do.

More preferably, on the surface of the parts to which the laser point of the fiber laser is to be joined, the laser point is selected to have a diameter in the range of 10 μm to 60 μm, in particular in the range of 15 μm to 40 μm.

More preferably, when there are three weld seams, the centerline of the intermediate first weld seam has a first distance with respect to the centerline of the second weld seam, and the first distance is a first centerline with respect to the third centerline of the third weld seam. Is equal to the second distance.

Preferably the speed at which the first, second and third weld seams are formed is provided in the range of 3.0 m / min to 8.0 m / min, in particular 4.3 m / min to 5.3 m / min, in particular about 4.8 m / min. to be.

Also to manufacture a fiber laser weld joint, the fiber laser can be moved or both parts can be moved, or the fiber laser and both parts can be moved. However, the embodiment in which the two parts are moved, in particular rotated, is preferred.

The welding process by the fiber laser is preferably carried out in a nitrogen atmosphere. More preferably the first and second parts are pressed against each other with a predetermined force on the joining point. The predetermined force is preferably in the range of 200 Nm to 350 Nm, preferably 300 Nm. According to another preferred embodiment of the invention, in the case of a part with a closed circumference, three weld seams start and end at each offset in the circumferential direction, each offset being preferably 120 °.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings.

1 is a schematic view of an injector including a parts assembly according to a first embodiment,
2 is an enlarged detail view of the component assembly of FIG. 1 including a fiber laser weld joint,
3 is an enlarged view of a component assembly according to a second embodiment of the present invention;
4 and 5 are schematic diagrams of intermediate steps in the manufacture of the fiber laser weld joint of FIG. 3 according to the method according to the invention,
6 is a schematic view of melting seams for explaining the positioning of start points and end points of welding seams according to a second embodiment.

Hereinafter, a method of manufacturing a component assembly and a fiber laser welding joint according to a preferred embodiment will be described in detail with reference to FIGS. 1 and 2.

1 shows an injector 100 with a longitudinal axis X-X comprising a component assembly 1 according to the invention. The part assembly 1 comprises a first part 10 and a second part 20.

In this embodiment, the first component 10 is an inner pole of the injector 100 and the second component 20 is a connecting sleeve for hydraulically connecting the injector 100.

The injector 100 comprises injection holes 101 and a magnetic actuator 102, wherein the first component 10 is here part of the magnetic actuator 102. Also shown are hydraulic connections 103 and electrical connections 104.

2 shows a detail of the assembly 10. A fiber laser welding joint 2 connects the first part 10 with the second part 20. It is shown in the detail of FIG. 2 that the fiber laser weld joint 2 comprises a first weld seam 3 and a second weld seam 4.

Two welding seams 3, 4 are arranged over the joint gap 6 between the parts 10, 20 to be joined so that a secure connection between the parts is achieved. The first welding seam 3 is arranged over the joint gap 6 such that the first welding seam 3 at least partially covers the joint gap 6. The second welding seam 4 is then set on the first side of the first welding seam 3. Here too, the second welding seam 4 partially covers the joint gap 6. As shown in FIG. 2, the positioning of the first and second welding seams 3, 4 preferably places the joint gap 6 exactly between the first and second welding seams 3, 4. To be done.

In addition, the width B1 of the first welding seam 3 is equal to the second width B2 of the second welding seam 4. Reference numeral M1 denotes a center line of the first welding seam 3 and M2 denotes a center line of the second welding seam 4. Since the distances of the joint gap 6 and the centerlines M1 and M2 are the same, a symmetric fiber laser welding joint 2 is obtained with respect to the joint gap 6.

As further shown in FIG. 2, the depths T of the two welding seams 3, 4 are also the same. The depth T of each weld seam is about 50% of the wall thickness W of the hollow cylindrical parts 10, 20 to be connected to each other. Weld seams taper in the depth direction. The aspect ratio of T to the first width B1 or the second width B2 is greater than five.

The welding seams 3, 4 are thus formed with the same setting parameters by means of a fiber laser. The fiber laser is preferably directed perpendicularly onto the surface of the parts 10, 20 to be connected to each other.

The start and end points of the two welding seams 3, 4 are offset from one another in the circumferential direction to prevent material accumulation in the manufacture of the first and second welding seams 3, 4. In the case of two weld seams the start and end points are arranged on the parts, preferably offset from each other by 180 °.

Preferably the laser point of the fiber laser is selected such that the laser point has a diameter of 10 to 60 μm, and in particular 15 to 40 μm. The rotation of the components to be joined or the rotation of the fiber laser is effected or the rotation of the components and the fiber laser is achieved. The rotational speed is preferably in the range of 3 rps.

The parts 10, 20 to be connected to each other are preferably tensioned with a pre-stress of 300 N in the clamping device.

Hereinafter, a component assembly according to a second embodiment of the present invention will be described in detail with reference to FIGS. 3 to 6. Identical or functionally identical parts have the same reference numerals.

Unlike the first embodiment, the component assembly 2 of the second embodiment has a total of three welding seams, namely a first welding seam, a second welding seam 4 and a third welding seam 5.

The first welding seam 3 is arranged in the middle between the second welding seam 4 and the third welding seam 5. The second and third weld seams 4, 5 are arranged next to and in contact with the first weld seam 3.

The first width B1 of the first welding seam 3 is equal to the second width B2 of the second welding seam 4 and the same as the third width B3 of the third welding seam 5. Thus the weld seams are formed with the same width.

As further shown in FIG. 3, the depths T of the three welding seams 3, 4, 5 are also the same.

In this embodiment, the first and second parts 10, 20 are also hollow cylindrical parts, and the depth T of each of the welding seams 3, 4, 5 is of the two parts 10, 20 to be connected to each other. It is about 50% of the wall thickness (W).

Three welding seams 3, 4, 5 forming the fiber laser welding joint 2 are formed with the same setting parameters. The fiber laser is directed vertically onto the surface of the parts 10, 20 to be connected to each other.

As shown in FIG. 3, the first welding seam 3 is set directly in the joint gap 6 between the two parts 10, 20. In this case the center of the first welding seam 3 is arranged above the joint gap 6.

The three weld seams 3, 4, 5 are also completely surrounded because the two parts 10, 20 to be connected are parts with a closed perimeter. The start points and the end points 7, 8 of the three weld seams 3, 4, 5 are offset from one another in the circumferential direction to prevent material accumulation or undesirable dissolution of the already set welding seam. Preferably the start points and the end points 7, 8 are each arranged to be offset by 120 °, which is schematically shown in FIG. 6.

In the method according to the invention for manufacturing the fiber laser weld joint 2 between the first part 10 and the second part 20, firstly the two parts 10, 20 are joined against each other, The joint gap 6 is given. The outer diameter of the first part is the same as the outer diameter of the second part. A first weld seam 3 is then produced first, the first weld seam being formed symmetrically over the joint gap 6 and with respect to the joint gap 6. In the next step a second weld seam 4 is produced, and a second weld seam 4 is made next to the first weld seam 3 and in contact with the first weld seam 3. This is shown in FIG.

In a next step a third weld seam 5 is produced which is arranged on the second side of the first weld seam 3 and is also formed next to and in contact with the first weld seam 3. The fiber laser is directed at an angle of 90 ° onto the surface of the parts 10, 20.

More preferably, the second center line M2 of the second welding seam is equal to the distance A2 between the center line M1 of the first welding seam and the third centerline M3 of the third welding seam. Three welding seams 3, 4, 5 are arranged so as to be spaced apart from). The distance A1, A2 between the centerlines M1, M2, M3 is preferably in the range of 40 to 80 μm, particularly preferably about 60 μm.

Due to the low focus diameter of the fiber laser, weld seams can be manufactured with very small seam widths and large aspect ratios in the described embodiments. Higher feed rates are achieved at the same power compared to other welding systems. This reduces the maximum transverse deformation of the parts. Very short processing times can also be achieved simultaneously with relatively low power requirements and reduced heating of the components.

The relatively low power introduction of the fiber laser does not cause plastic deformation of both or both of the parts 10, 20. The seam width of the weld seams formed by the high welding speed of about 4.8 m / min is also reduced. Thus, a reduction of the so-called nail head is obtained on the outer region of the weld seam.

For example, a fiber laser was set up as follows to connect the two hollow cylindrical parts 10, 20 of the injector 100: the maximum power was 320W. The diameter of the laser point was 25 micrometers. The weld seams formed had a width of 300 μm on the outer face of the parts. Welding seams inside the connected parts had a width of 120 μm. The moving speed between the laser and the part was 4.8 m / min and the welding process was carried out under nitrogen. Weld seams started and ended offset from each other in the circumference. Inspection by computed tomography confirmed that there was no gap in the fiber laser weld joint. The use of fiber lasers reduces the introduction of heat into the parts. Small heat introduction and minimal welding distortion also increase the strength of the weld joint and reduce the residual stress of the weld seams. The geometric dimensions of the weld seams are thus improved and there is no gap formation in the weld seams between the parts to be joined.

Thus, in accordance with the present invention, an effective and economical connection of the two parts 10, 20 can be achieved by setting at least two welding seams by means of a fiber laser. The invention is particularly suitable when connecting two parts of an injector, in particular a hollow cylindrical inner pole and a hollow cylindrical connecting sleeve, which two parts have the same outer diameter. Although at least two welding seams are provided, the welding time can be significantly reduced compared to the prior art. This makes it possible to realize significant cost savings, especially in the manufacture of high-volume parts such as injectors. If the parts are hollow cylindrical, a fiber laser weld joint 2 can also be produced on the inner circumference of the parts.

2: fiber laser welding joint
3: first welding seam
4: second welding seam
5: third welding seam
6: joint gap
10: first part
20: second part
A1: 1st street
A2: 2nd street
M1: first center line
M2: second centerline
M3: third centerline

Claims (21)

A first part (10),
Second component 20, and
A fiber laser weld joint 2 between the first part 10 and the second part 20 for connecting the first part 10 and the second part 20 in a joint gap 6. In a component assembly comprising a,
The fiber laser welding joint 2 comprises at least one first welding seam 3 and a second welding seam 4,
The first welding seam (3) and the second welding seam (4) are arranged in direct contact with each other and in contact with each other. The assembly of claim 1, wherein the first welding seam (3) is disposed over the joint gap (6) between the first component (10) and the second component (20). The assembly of claim 1, wherein the second welding seam (4) is disposed over the joint gap (6) between the first component (10) and the second component (20). The method according to any one of claims 1 to 3, wherein each of the first component 10 and the second component 20 is a closed component, and the fiber laser weld joint 2 is also closed. Parts assembly. 5. The component assembly as claimed in claim 1, wherein the component assembly further comprises a third welding seam 5, wherein the second welding seam 4 and the third welding seam 5 comprise the first welding seam 5. A component assembly disposed next to a first weld seam (3) and in contact with the first weld seam (3). 6. The assembly of claim 5, wherein the center of the first welding seam (3) is disposed above the joint gap (6) between the first component (10) and the second component (20). The first distance A1 according to claim 5 or 6, wherein the first center line M1 of the first welding seam 3 and the second center line M2 of the second welding seam 4 are And a second distance (A2) between the first centerline (M1) and the third centerline (M3) of the third weld seam (5). 8. The start point according to claim 1, wherein the start points and the end points of the weld seams are arranged to be offset from each other in the circumferential direction, in particular 360 ° to be offset from each other at an angle divided by the number of the weld seams. Parts assembly. 9. The component assembly according to claim 1, wherein the widths (B1; B2; B3) of the welding seams are each the same. 10. A component assembly as claimed in claim 1, wherein the fiber laser weld joint (2) does not completely penetrate the components (10, 20). The width of one of the welding seams of one of the welding seams on the surface of the parts is in the range of 250 to 350 μm, in particular in the range of 260 to 320 μm. Parts assembly. An injector, in particular a fuel injector, comprising a component assembly (1) according to any of the preceding claims. 13. Injector according to claim 12, wherein the first part (10) is an inner pole of the injector and the second part (20) is a sleeve, in particular a connecting sleeve, of the injector. As a manufacturing method of the fiber laser welding joint 2 between the first component 10 and the second component 20,
Positioning the first part 10 and the second part 20 such that the parts lie adjacent to one another in the joint gap 6,
Manufacturing a first weld seam 3 between the first part and the second part in the region of the joint gap 6 by means of a fiber laser, and
Manufacturing a second weld seam (4) lying directly adjacent to the first weld seam (3) on the first side and in contact with the first weld seam (3). The third welding seam according to claim 14, wherein the third welding seam lies directly adjacent to the first welding seam 3 on the second side of the first welding seam 3 and is in contact with the first welding seam 3. 5) further comprising the step of manufacturing. 16. The method according to claim 14 or 15, wherein the fiber laser is directed perpendicularly onto the surface of the first part and the second part to be joined. Method according to one of the claims 14 to 16, wherein the starting and / or end points of the welding seams (3, 4, 5) are arranged to be offset in the longitudinal direction of the welding seams. 18. A method according to any one of claims 14 to 17, wherein the first part and the second part are closed-circuit parts, in particular cylindrical parts. 19. A method according to claim 18, wherein each offset between the starting point and the ending point of each said welding seam (3, 4, 5) consists of 360 degrees divided by the number of said welding seams. 20. The method according to claim 14, wherein the laser point of the fiber laser has a diameter in the range of 10 to 60 μm, in particular in the range of 15 to 40 μm on the surface of the parts to be joined. Eggplant manufacturing method. 21. The method according to claim 14, wherein the welding speed is in the range of 3.0 m / min to 8.0 m / min, in particular about 4.8 m / min.

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