Weld-coupled working cylinder assembly and method for producing same

Abstract

The invention relates to a weld-coupled working cylinder assembly, having a working cylinder component (1), an attachment part (2) and a weld seam (3), and is characterised in that the weld seam (3) is formed as a stepped hybrid weld seam, which has a lower weld seam zone (4) and an upper weld seam zone (5), in that, in the lower weld seam zone (4), the working cylinder component (1) has a lower working cylinder component seam surface (4.1) and the attachment part (2) has a lower attachment part seam surface (4.2), and in that the lower seam surfaces (4.1, 4.2) have a butt joint (4.3) and in that the lower weld seam zone (4) is formed as a laser weld seam, in that, in the upper weld seam zone (5), the working cylinder component (1) has an upper working cylinder component seam surface (5.1) and the attachment part (2) has an upper attachment part seam surface (5.2), and in that the upper seam surfaces (5.1, 5.2) have a surface separation (5.3), and in that the upper weld seam zone (5) is formed as a laser hybrid weld seam and has a filling of welding filler material (5.6) in an upper weld seam space (5.5) formed by the surface separation (5.5). The invention further relates to a method for producing such a weld-coupled working cylinder assembly.

Description

[0001] Welded-coupled working cylinder assembly and method for its manufacture

[0002] The invention relates to a weld-coupled working cylinder assembly and a method for producing such a working cylinder assembly, in particular for hydraulic working cylinders with high actuating forces.

[0003] It is known from the prior art to equip hydraulic working cylinders with attachments for transmitting the actuating forces generated by the working cylinder to the devices to be actuated. Such attachments can, in particular, be so-called ball joints.

[0004] Furthermore, it is generally known from the state of the art to weld such attachments. Since welded joints are intended to absorb very high forces in larger hydraulic cylinders, the welds, which are produced, for example, as MAG welds, must have a large weld area and thus a large weld depth.

[0005] The disadvantage here is that, on the one hand, a high heat input is required, which carries the risk of scaling in the working cylinder, thermal distortion, or damage to components with less thermal resistance, such as seals or guides. Furthermore, the high consumption of welding wire and energy is a disadvantage.

[0006] It is also known from the state of the art to produce laser welded joints, whereby very high laser powers must be used to achieve the required weld depths, which disadvantageously makes laser welding very expensive and uneconomical.

[0007] The object of the invention is to provide a welded working cylinder assembly that has a very high load capacity and can be manufactured in a resource-saving and economical manner. Furthermore, the object of the invention is

[0008] Confirmation copy to specify a reliable and at the same time economical method for manufacturing such a working cylinder assembly.

[0009] The problem is solved with respect to the working cylinder assembly by the features listed in patent claim 1 and with respect to the manufacturing method by the features listed in patent claim 5. Preferred developments arise from the respective subclaims.

[0010] The weld-coupled working cylinder assembly according to the invention has as basic components a working cylinder component, an attachment part and a weld seam.

[0011] The working cylinder component is designed in a conventional manner as a piston rod or as a closure part. Working cylinders, within the meaning of the present invention, are understood to be linear pressure flow consumers in which a pressure medium acts on a piston surface, thus providing an actuating force that can be in the form of a thrust or pressure force. The working cylinder is preferably a hydraulic working cylinder. This can be designed, for example, as a differential working cylinder, pull cylinder, constant-speed cylinder, or plunger cylinder.

[0012] The working cylinder component is the component of the working cylinder from which the actuating force is taken. This can be, in particular, a closure part such as a bottom closure part. It can also be a piston unit, in particular a piston rod, whereby the piston rod is also understood to be the outer section of a plunger piston.

[0013] The attachment is a coupling module designed for coupling to a device to be actuated for power transmission. When the working cylinder is used as intended, the coupling module is connected to a device to be actuated. This is usually an articulated connection, and the coupling module is designed as a spherical bearing, also known as a joint eye or joint head. However, the coupling module can also be designed in other ways.

[0014] The working cylinder component and the attachment are collectively referred to below as the coupling partners.

[0015] Furthermore, the weld-coupled working cylinder assembly according to the invention has a weld seam that firmly connects the working cylinder component and the attachment.

[0016] According to the invention, this weld seam is constructed in a special way and is characterized in that it is designed as a stepped hybrid weld seam.

[0017] For this purpose, the weld seam has a lower weld zone and an upper weld zone. The designations "lower weld zone" and "upper weld zone" are to be understood independently of the spatial position. With respect to a weld seam depth, the designation "lower weld zone" refers to the section facing away from the component surface and the direction of action of the welding material. With respect to a weld seam depth, the designation "upper weld zone" refers to the section adjacent to the component surface, covering the lower weld zone, and facing the direction of action of the welding material.

[0018] In the lower weld zone, the working cylinder component has a lower working cylinder component weld surface, and the attachment has a lower attachment weld surface. The lower working cylinder component weld surface and the lower attachment weld surface are collectively referred to as the lower weld surfaces.

[0019] According to the invention, the lower seam surfaces have a butt joint, which is bonded together by a laser weld. The laser weld is flush with the surface and without a gap, and the welding is carried out without filler metal.

[0020] In the upper weld zone, the working cylinder component and the attachment also have identically shaped weld surfaces, which are spaced a certain distance apart. The resulting space is referred to as the weld seam cavity. This arrangement allows the laser beam to pass through, enabling laser welding in the lower weld zone.

[0021] Here, the working cylinder component has an upper working cylinder component weld surface, and the attachment has an upper attachment weld surface. The upper working cylinder component weld surface and the upper attachment weld surface are collectively referred to as the upper weld surfaces. The lower and upper weld surfaces are collectively referred to as the weld surfaces.

[0022] The upper weld surfaces are spaced apart by a surface distance. This means that the upper weld surfaces are essentially plane-parallel and spaced apart from each other. The space thus spanning between the upper weld surfaces is referred to as the upper weld seam space. The upper weld seam space is arranged in such a way that it provides a clear cross-section for a laser beam to create the laser weld seam in the lower weld zone.

[0023] Under these design conditions, the upper weld zone is formed as a laser hybrid weld and represents an essential part of the inventive solution, since here the laser beam simultaneously melts the preferably approximately 0.8 mm thick welding electrode. The upper weld zone thus has a filler material filling that fills the upper weld space and thus indirectly connects the upper seam surfaces to one another in a materially bonded manner. The laser hybrid weld of the upper weld zone is a so-called I-seam, which, according to the invention, has a greater width than the laser weld of the lower weld zone. The upper weld space thus advantageously fulfills two functions simultaneously that are essential to the inventive solution.

[0024] It allows unhindered access for the laser beam to the lower weld zone.

[0025] It provides the space required to accommodate the welding filler material.

[0026] The welding filler material is preferably the material of a welding wire. The welding medium in the upper weld zone is also a laser beam. Here, the laser beam is applied to the upper weld zone subsequent to the laser beam in the lower weld zone. Preferably, it is the same laser beam that is applied again subsequent to the lower weld zone and now strikes the welding filler material filling in the upper weld space. This can be achieved particularly advantageously with rotationally symmetrical welding partners, since the lower and upper weld seams can be created consecutively. The lower weld seam is created in the first rotation cycle, and the filler material is melted in the second rotation cycle, thus simultaneously filling the free space between the welding partners in the upper weld space.

[0027] The coupling provided according to the invention can also be referred to as a laser-laser hybrid coupling or as a stepped hybrid welding. It has the following advantages in particular.

[0028] The butt joint of the lower weld zone ensures particularly precise positioning, as this weld surface holds the weld partners in position without distortion during the immediately following cooling process. A further advantage is the increased energy efficiency, as the solidification heat released from the lower weld zone acts as a preheating factor for the upper weld zone. Furthermore, from a manufacturing technology perspective, dividing the entire weld into two weld zones allows for the use of lower laser power, allowing the use of lower-power laser welding systems, which has a significant positive impact on investment costs. Laser hybrid welding is possible with all known laser beam generation technologies, such as YAG lasers and CO2 lasers, and is not tied to a specific type of laser generation.Another technological advantage from a manufacturing perspective is the high process speed with which seams can be produced, completely eliminating expensive and time-consuming processes such as friction welding and prefabricated forgings. Ultimately, the reduction in heat during the welding process improves the quality of the joint by completely eliminating scaling and, as a result, protecting sensitive elements of the working cylinder.

[0029] In detail, the following applies in addition.

[0030] A coupling of particularly high quality is provided. The butt joint of the lower weld zone enables particularly precise positioning of the coupling partners relative to one another. A surprising solution was found that reliably maintains this precise positional relationship even during and until completion of the welding process and provides it for the finished weld-coupled working cylinder assembly. Advantageously, a very low energy per unit length is initially applied in the lower weld zone, thus minimizing thermal advantage. This possible low energy per unit length is based on the laser welding technology, but also on the reduction of the total weld depth, initially to the lower weld zone depth.In addition, the introduced heat energy acts directly only on the lower weld zone, so that the initially cold material body in the upper weld zone supports the material body in the lower weld zone and additionally counteracts its thermal deformation. In this context, there is also the advantage that the creation of the upper weld space provides direct access for the laser beam to the lower weld zone without any additional effort.

[0031] Furthermore, the laser beam advantageously creates a very narrow melting zone in the lower weld zone, introducing correspondingly little heat energy. This can be very quickly removed into the material of the coupling partners via the lower weld surfaces, resulting in rapid solidification in the lower weld zone. This ensures that the coupling partners are already firmly fixed in their position by the time the cooling and solidification phase in the upper weld zone, which takes longer due to the wider weld and the higher heat input, continues, thus counteracting thermal distortion caused by the upper weld zone.

[0032] A further advantage is the increased energy efficiency. The solidification heat released as a result of the solidification of the melting zone in the lower weld zone is dissipated into the material of the coupling partners and provides preheating for the weld in the upper weld zone, so that the applied heat energy can be reduced by this amount. Particularly advantageous is that the upper weld zone is heated from below, so that the heat input from the laser beam during its second application from above achieves rapid melting and thermal homogenization in the upper weld zone.

[0033] Furthermore, it is advantageous from a manufacturing technology perspective that both the lower laser weld seam and the upper laser hybrid weld seam require lower laser power than would be the case with laser welding of the entire weld seam. Thus, to produce the weld-coupled working cylinder assembly according to the invention, cost-effective laser welding systems with lower power outputs of approximately 5 to 10 kW can also be used for the production of medium-sized hydraulic working cylinder assemblies, significantly reducing investment costs. Furthermore, a welding filler material such as welding wire is advantageously only required for the upper weld seam zone, thus enabling material and cost savings.

[0034] Advantageously, the weld seam can be formed both vertically and inclined.

[0035] Ultimately, reducing the heating of the working cylinder component increases quality by avoiding scaling or damage to thermally sensitive elements.

[0036] According to claim 2, according to another aspect of the invention, the working cylinder component is a cylinder tube, and the attachment is a closure part or additional closure part. This can be either the closure part—in particular designed as a base closure part—welded to a coupling module according to the invention, or another closure part that is not welded to a coupling module according to the invention. In particular, it can also be a guide closure part. A closure part or additional closure part within the meaning of this further aspect of the invention is hereinafter referred to as a closure part.

[0037] The weld seam according to this further aspect of the invention thus couples the cylinder tube to the closure part. The upper weld seam zone is designed as an outer annular surface, and the lower weld seam zone is designed as an inner annular surface. Furthermore, all descriptions of the weld seam in a welded coupling between a piston rod or a closure part with a coupling module also apply correspondingly to a weld seam in a welded coupling between the cylinder tube and a closure part.

[0038] This aspect of the invention is particularly advantageous for a welded coupling according to the invention in heavy hydraulic cylinders. Heavy hydraulic cylinders are understood to be hydraulic cylinders with a cylinder tube wall thickness of 10 mm or more, particularly preferably 15 mm or more. In this case, cylinder tube inner diameters of 100 mm or more, particularly preferably 150 mm or more, are preferred.

[0039] The manufacturing advantages, especially the saving of costly welding consumables, the reduction of laser costs and the improvement of precision, are significant for heavy hydraulic cylinders.

[0040] According to an advantageous development, the weld-coupled working cylinder assembly is characterized in that a lower weld zone surface and an upper weld zone surface form a total weld zone surface, and that the area ratio of the lower weld zone surface to the total weld zone surface is 15% to 40%. This area ratio is particularly preferably 20% to 30%. It has been experimentally proven that the weld can be produced extremely precisely and without distortion at this ratio.

[0041] Rapid solidification of the melting zone in the lower weld zone is achieved.

[0042] The weld surfaces, particularly in the case of a welded coupling on a piston rod, are rotationally symmetrical geometries. In rotationally symmetrical parts, the lower weld zone is an inner circular surface when fully welded, and the upper weld zone is an annular surface that radially encloses the lower weld zone. The inner circular surface of the lower weld zone and the outer circular surface of the upper weld zone together form a total circular surface, which constitutes the total weld zone area; both surfaces thus form the total weld. According to this development, the area ratio of the inner circular surface to the total circular surface is 15% to 40%, and particularly preferably 20% to 30%. The advantage is that the two zones to be welded can be realized with just one clamping by two consecutive rotations.According to a further advantageous development, the weld-coupled working cylinder assembly is characterized in that the surface spacing in the upper weld seam zone is 0.5 mm to 2.0 mm. Particularly preferably, the surface spacing is 1.0 mm to 1.5 mm.

[0043] It was found that this surface distance, on the one hand, advantageously enables good penetration of the laser beam into the lower weld zone and, on the other hand, enables low consumption of welding filler material, in particular welding wire, as well as a comparatively low energy per unit length in the upper weld zone while at the same time ensuring reliable welding even in the upper weld zone.

[0044] According to a further advantageous development, the weld-coupled working cylinder assembly is characterized in that the lower weld zone surface is designed as an inner circular surface or as an inner annular surface, and that the upper weld zone surface is designed as an outer annular surface that radially encloses the lower weld zone surface. Both partial surfaces together form the overall weld zone surface, which can then be present either as an overall circular surface or as an overall annular surface.

[0045] This refinement is advantageous in that, after the laser weld is created, the heat dissipation of the lower weld zone is lower than that of the upper weld zone due to the radial geometry. This further improves preheating of the upper weld zone. At the same time, this refinement is advantageous from a manufacturing technology perspective, as the lower weld zone and the upper weld zone can be realized sequentially and in one clamping by two consecutive rotations of the prepositioned coupling partners under the laser beam.

[0046] According to a further aspect of the invention, a method for producing a weld-coupled working cylinder assembly is provided, wherein the working cylinder component is designed as a piston rod or a closure part, and wherein the attachment is designed as a coupling module. The coupling module is designed for coupling to a power transmission device to be actuated.

[0047] The method comprises the following work steps: a) Providing the working cylinder component and the attachment, b) Producing the weld surfaces to be joined, namely producing a lower working cylinder component weld surface and a lower attachment weld surface as well as an upper working cylinder component weld surface and an upper attachment weld surface, wherein at least one of the upper weld surfaces has a recess relative to the respective lower weld surface, c) Positioning the working cylinder component and the attachment to a subassembly while producing a butt joint of the lower weld surfaces and a surface spacing of the upper weld surfaces, d) Laser welding the lower weld surfaces using a laser beam to produce a laser weld seam in the lower weld seam zone, e) Laser hybrid welding the upper weld surfaces using the laser beam and supplying a welding filler material,Melting the welding filler material using the same laser beam and filling an upper weld seam space between the upper weld surfaces.

[0048] The description of the welded working cylinder assembly and the definitions of terms therein also apply accordingly to the process for its manufacture.

[0049] In process step a), the working cylinder component and the attachment are prepared. These two coupling parts are manufactured in a conventional manner.

[0050] In process step b), a lower working cylinder component weld surface and a lower attachment weld surface as well as an upper working cylinder component weld surface and an upper attachment weld surface are produced, wherein at least one of the upper weld surfaces has a recess relative to the respective lower weld surface.

[0051] Since the weld surfaces are usually rotationally symmetrical component sections, they are preferably manufactured by turning or milling. Preferably, the lower weld surfaces, in particular, are formed to be exactly flat. With a symmetrical design, the recess of the upper weld surfaces is half the desired surface spacing. However, an asymmetrical distribution of the recesses is also possible. Furthermore, in special cases, one coupling partner can be created with weld surfaces that are flush with each other and only the other coupling partner with a recess, so that this recess alone provides the surface spacing.

[0052] In process step c), the positioning of the working cylinder component and the attachment to form a pre-assembly is carried out by producing a butt joint of the lower weld surfaces and a surface spacing of the upper weld surfaces.

[0053] In this process, the coupling partners are preferably pressed axially against each other so that the lower seam surfaces are in pressure contact with each other. This also involves aligning both coupling partners along a longitudinal axis according to the desired subsequent position of the attachments relative to the longitudinal axis of the working cylinder assembly. This resulting positional relationship is then maintained during the subsequent process steps, preferably until their completion.

[0054] In process step d), the lower seam surfaces are laser welded using a laser beam, creating the laser weld in the lower weld zone. According to the invention, the surface spacing of the upper seam surfaces creates an upper weld space that provides the laser beam with unobstructed access to the upper beginning of the lower weld zone. The laser beam preferably penetrates exactly in the plane spanned by the butt joint of the lower seam surfaces and melts the seam surfaces at their surface, thus providing a thin, planar melt which, after solidification, firmly bonds the coupling partners on the lower seam surfaces and forms the laser weld. The laser weld is created in process step d) without the addition of any welding filler material.

[0055] According to the invention, the solidification heat is at least partially dissipated upwards into the upper weld zone. This advantageously achieves both heating of the upper weld zone and removal of the heat input into the lower weld zone, thus avoiding undesirably strong heating in the area surrounding the lower weld zone.

[0056] In process step e), the laser hybrid welding of the upper seam surfaces is performed. The laser hybrid welding of the upper seam surfaces is performed using the laser beam and the supply of a welding filler material, filling an upper weld seam space between the upper seam surfaces.

[0057] In the upper weld zone, which has already been preheated by process step d), the upper weld surfaces are further heated until they begin to melt by renewed application of a laser beam. According to the invention, welding filler material is added, preferably via a welding wire, which is melted, forms part of the melt in the upper weld zone and fills the upper weld space between the upper weld surfaces, thus directly adjoining the upper weld surfaces. Once the upper weld space has been filled with the melt, the laser beam is removed and the upper weld zone cools down, solidifying the melt in the upper weld space and forming an indirect material bond between the upper weld surfaces and thus the hybrid weld.The indirect material bond is based on the fact that the material bond between the upper weld surfaces is mediated by the solidified melt with the participation of the welding filler material.

[0058] As a result of carrying out all process steps, the weld-coupled working cylinder assembly is obtained, which has a laser-laser hybrid weld seam according to the invention.

[0059] The invention further encompasses the possibility of carrying out method step e) repeatedly, thus resulting in the upper weld seam space being filled layer by layer with the filler material.

[0060] The advantages described for the weld-coupled working cylinder assembly according to the invention apply to the method in a corresponding manner.

[0061] In particular, it is advantageous that, due to the low heat input per unit length and the very narrow melting zone on the lower weld surfaces, solidification occurs in process step d) when the upper weld zone, with its melting zone wider due to the surface spacing between the upper weld surfaces, has not yet solidified into the upper weld space. This already creates a connection between the coupling partners, which defines their positional relationship and protects against distortion due to the subsequent solidification of the upper weld zone. At the same time, the same advantages that were presented due to the importance of using lower-power laser welding systems also become effective in the process.

[0062] The laser hybrid weld seam of the upper weld zone is created - at one point at a time - with a time offset from the creation of the laser weld seam of the lower weld zone of preferably 2 to a maximum of 10 seconds.

[0063] Furthermore, for rotational components, i.e. when an upper weld seam surface is present as an outer circular ring surface, increased flexural rigidity is created at the weld seam without additional measures. This is based on the fact that the lower laser weld seam has already solidified and thermally shrunk when the upper laser hybrid weld seam is created. The subsequent thermal shrinkage of this weld seam creates an elastic prestress in the upper weld seam zone surface, which here is present as an outer circular ring surface. This is supported by the fact that the upper weld seam zone is wider than the lower weld seam zone with a butt joint due to the surface spacing of the upper seam surfaces, and thus the thermal shrinkage of the upper weld seam zone is greater than that of the lower weld seam zone.The degree of prestress can advantageously be adjusted as required by means of the area ratio of the lower weld zone area and the upper weld zone area as well as by means of the surface distance of the upper weld surfaces, thus obtaining an assembly consisting of the working cylinder component and the attachment part with improved mechanical properties.

[0064] According to a next advantageous development, the method for producing a weld-coupled working cylinder assembly is characterized in that a heat energy applied in the lower weld zone in method step d) relative to a lower weld zone area is lower than a heat energy applied in the upper weld zone in method step e) relative to an upper weld zone area.

[0065] Advantageously, the weld zone area-related lower energy per unit length in the lower weld zone in process step d) compared to the energy per unit length of the upper weld zone in process step ensures that solidification occurs earlier in the lower weld zone than in the upper weld zone and the positional relationship of the coupling partners is already stabilized when distortion forces act on the coupling partners as a result of the solidification of the upper weld zone.

[0066] According to a further advantageous development, the method for producing a weld-coupled working cylinder assembly is characterized in that the energy input per unit length introduced into the lower weld zone in process step d) simultaneously corresponds to the melting requirements of the welding filler material for the upper weld zone. The welding of each of the two weld zones can thus be achieved with the same laser power and the same speed.

[0067] According to a further development, the method for producing a weld-coupled working cylinder assembly is characterized in that the lower seam surfaces are designed as an inner circular surface or an inner annular surface, that the upper seam surfaces are designed as an outer annular surface which radially encloses the inner circular surface or inner annular surface and that in method step d) a relative movement of the pre-assembly to the laser is carried out by means of a rotation of the pre-assembly and that in method step e) a relative movement of the pre-assembly to the laser is carried out by means of a further rotation of the pre-assembly.

[0068] The advantages of the method according to the invention are particularly evident in the rotationally symmetrical coupling sections of the working cylinder component and the attachment. Once the coupling partners have been joined to form the pre-assembly and fixed in their relative position, they can be guided and welded by rotation under the laser, ensuring reliable, even laser exposure. The first rotation creates the laser weld seam according to process step d). After completing a 360-degree rotation, another full rotation is performed, feeding the filler material into the upper weld seam space. The laser beam now strikes the filler material, creating a melt that fills the upper weld seam space and indirectly bonds the upper seam surfaces.After completion of the second full rotation, the laser hybrid weld seam is also created according to process step e).

[0069] According to another development, the method for producing a weld-coupled working cylinder assembly is characterized in that process step d) and process step e) are carried out in parallel, that a relative movement of the pre-assembly is carried out along the weld seam, and that the laser beam according to process step e) is arranged offset from the laser beam according to process step d) along the direction of the relative movement. This development requires the use of two laser beams and enables a further improvement in the latter's efficiency.

[0070] According to this refinement, the process is carried out with two laser beams, which are applied in parallel but linearly offset along the feed motion. This spatial offset, together with the line speed of the laser welding, allows the temporal offset of the laser application in the lower weld zone and in the upper weld zone to be precisely adjusted at the same linear position of the weld seam, thus optimizing the weld seam formation. This makes it possible to keep the temporal offset sufficiently small, especially for particularly large assemblies.

[0071] The invention is illustrated by way of example with reference to

[0072] Fig. 1 : Overall view of a working cylinder assembly as a sectional view,

[0073] Fig. 2: Schematic sectional view of the weld seam area before joining as a pre-assembly, Fig. 3: Schematic sectional view of the weld seam area in the pre-assembly state,

[0074] Fig. 4: Schematic sectional view of the weld seam,

[0075] Fig. 5: Schematic representation of the process in process step d),

[0076] Fig. 6: Schematic representation of the process in process step e),

[0077] Fig. 7: Schematic representation of the process with parallel execution of process steps,

[0078] Fig. 8: Schematic representation of the process when rotating the pre-assembly, explained in more detail.

[0079] Identical reference symbols in the various figures refer to identical features or components. These reference symbols are used in the description even if they are not shown in the respective figure.

[0080] Fig. 1 shows an overall view of the working cylinder assembly, which in the exemplary embodiment is a differential working cylinder. In this exemplary embodiment, the working cylinder component 1 is designed as both a piston rod 1.1 and a closure part 1.2. Both the piston rod 1.1 and the closure part 1.2 are each connected to an attachment 2, in this case a spherical bearing, via a weld seam 3.

[0081] According to Fig. 1, it is further shown that the cylinder tube 1.4 is also designed as a working cylinder component 1, which is also connected on both sides via a weld seam 3 to the closure part 1.2 - here the base closure part - and the further closure part 1.3 - here the guide closure part. Here, the weld seam 3 between the cylinder tube 1.4 and the closure part 1.2 - the base closure part - is vertical, and the weld seam 3 between the cylinder tube 1.4 and the further closure part 1.3 - here the guide closure part - is inclined at a weld seam angle.

[0082] Fig. 2 shows the coupling partners 1, 2 after process step b) and before joining to the pre-assembly in process step c).

[0083] Fig. 3 shows the coupling partners 1, 2 after joining to the pre-assembly in process step c).

[0084] Fig. 2 and Fig. 3 are described together below. In the later lower weld seam zone 4, the lower working cylinder component weld surface 4.1 and the lower attachment weld surface 4.2 face each other as the lower weld surfaces 4.1, 4.2 and in the later upper weld seam zone 5, the upper working cylinder component weld surface 5.1 and the upper attachment weld surface 5.2 face each other as the upper weld surfaces 5.1, 5.2. The lower weld surfaces 4.1, 4.2 form the later lower weld seam zone surface 4.4 and the upper weld surfaces 5.1, 5.2 form the later upper weld seam zone surface 5.4. After joining in process step d), the lower weld surfaces 4.1, 4.2 form a butt joint and the upper weld surfaces 5.1, 5.2 form a surface spacing 5.3. Due to the surface spacing

[0085] 5.3 an upper weld seam space is formed between the upper weld surfaces 5.1 , 5.2

[0086] 5.4 formed.

[0087] Fig. 4 shows the weld seam after welding has been completed following process steps d) and e). The narrow laser weld seam is now present in the lower weld seam zone 4. In the upper weld seam zone 5, the upper weld seam space 5.5 is now provided with a welding filler material filling 5.6, which is formed by a welding wire melted by a laser beam 6. Both coupling partners are now firmly bonded by the laser weld seam in the lower weld seam zone 4 and the hybrid weld seam in the upper weld seam zone 5. Fig. 5 and Fig. 6 show the process when process steps d) and e) are carried out consecutively.

[0088] Fig. 5 shows method step d), in which the pre-assembly is guided under the laser beam 6 in the direction of movement shown by the arrow. The laser beam 6 strikes the lower weld seam zone 4 directly, penetrates the butt joint 4.3 and welds the lower seam surfaces 4.1, 4.2. As Fig. 6 shows, to carry out method step e), the laser beam 6 is subsequently applied again and for this purpose the pre-assembly, which has already been fixed and preheated via the lower weld seam zone 4, is guided again in the direction of movement shown by the arrow. At the same time, the welding filler material in the form of a welding wire is fed in and brought into the effective range of the laser beam 6 in the upper weld seam space 5.5 and there melted to a melt that now fills the upper weld seam space 5.5.

[0089] After solidification, the finished weld seam 3 is present, consisting of the laser weld seam in the lower weld zone 4 and the laser hybrid weld seam in the upper weld zone 5.

[0090] Fig. 7 schematically shows a modified embodiment of the method, the parallel execution of process steps d) and e). The arrow below indicates the direction of movement of the subassembly along the weld seam 3, shown here in longitudinal section. The laser beam 6 strikes the lower weld seam zone 3 directly, penetrates the butt joint 4.3, and welds the lower seam surfaces 4.1, 4.2.

[0091] By continuing to move the coupling partners 1, 2, they also reach the effective zone of another laser beam 6. The spatial distance also creates a time gap depending on the movement speed, which is dimensioned such that heat is dissipated from the lower weld seam zone 4, among other places, into the upper weld seam zone 5, thus causing the melt in the laser weld seam to solidify in the lower weld seam zone 4 and the upper weld seam zone 5 to preheat. The further laser beam 6 captures the supplied welding wire in the upper weld seam space 5.5, melts it, and indirectly captures the upper seam surfaces 5.1, 5.2 and melts them. The melt thus formed fills the weld seam space 5.5, where it forms the additional welding material filling 5.6 in the upper weld seam zone 5. Thus, after solidification, the laser hybrid weld seam is formed.

[0092] Fig. 8 shows schematically the method in an embodiment in which the lower weld zone 4 is formed as an inner annular surface and the upper weld zone 5 as a concentric outer annular surface.

[0093] As shown on the left, in process step d) the lower weld zone 4 is first created as a laser weld seam with a first rotation with the laser beam 6, until, after an angular position of 360 degrees in section along the weld seam, it is present as a completely closed inner ring surface.

[0094] As shown on the right, in process step e) the upper weld zone 5 is subsequently created as a laser hybrid weld with the laser beam 6 by a further rotation with the addition of a welding wire, until this too forms a completely closed outer ring surface after a full rotation.

[0095] Fig. 8 shows the two process steps after a rotation of approximately 240 degrees, with the arrows indicating the direction of rotation.

[0096] Reference symbols used

[0097] 1 working cylinder component

[0098] 1.1 Piston rod

[0099] 1.2 Closure part

[0100] 1.3 additional locking part

[0101] 1.4 Cylinder barrel

[0102] 2 attachment part

[0103] 3 Weld seam

[0104] 3.4 Total weld area

[0105] 4 lower weld zone

[0106] 4.1 lower working cylinder component weld surface

[0107] 4.2 lower attachment weld surface

[0108] 4.3 Butt joint

[0109] 4.4 lower weld zone area

[0110] 5 upper weld zone

[0111] 5.1 upper working cylinder component weld surface

[0112] 5.2 upper attachment weld surface

[0113] 5.3 Surface spacing

[0114] 5.4 upper weld zone area

[0115] 5.5 upper weld seam space

[0116] 5.6 Welding consumable filling

[0117] 6 lasers

Claims

Patent claims 1. Welded working cylinder assembly comprising a working cylinder component (1), an attachment component (2) and a weld seam (3), wherein the working cylinder component (1) is designed as a piston rod (1.1) or a closure part (1.2), wherein the attachment component (2) is designed as a coupling module designed for coupling with an actuated device for force transmission, characterized in that the weld seam (3) is designed as a stepped hybrid weld seam having a lower weld seam zone (4) and an upper weld seam zone (5), that in the lower weld seam zone (4) the working cylinder component (1) has a lower working cylinder component weld surface (4.1) and the attachment component (2) has a lower attachment component weld surface (4.2), and that the lower weld surfaces (4.1, 4.2) have a butt joint (4.3) exhibit and that the lower weld zone (4) is designed as a laser weld, that in the upper weld zone (5) the working cylinder component (1) has an upper working cylinder component weld surface (5.1) and the attachment component (2) has an upper attachment component weld surface (5.2) and that the upper weld surfaces (5.1 ,. 5.2) have a surface distance (5.3) and that the upper weld zone (5) is designed as a laser hybrid weld and has a welding filler material filling (5.6) in an upper weld space (5.5) formed by the surface distance (5.3).

2. Welded working cylinder assembly comprising a working cylinder component (1), an attachment component (2) and a weld seam (3), wherein the working cylinder component (1) is a cylinder tube (1.4), wherein the attachment part (2) is designed as the closure part (1.2) or as a further closure part (1.3), characterized in that the weld (3) is designed as a stepped hybrid weld having a lower weld zone (4) and an upper weld zone (5), that in the lower weld zone (4) the working cylinder component (1) has a lower working cylinder component weld surface (4.1) and the attachment part (2) has a lower attachment component weld surface (4.2), and that the lower weld surfaces (4.1, 4.2) have a butt joint (4.3), and that the lower weld zone (4) is designed as a laser weld, that in the upper weld zone (5) the working cylinder component (1) has an upper working cylinder component weld surface (5.1) and the attachment part (2) has an upper attachment component weld surface (5.2), and that the upper weld surfaces (5.1, 5.2) a surface spacing (5.3) and that the upper weld zone (5) is designed as a laser hybrid weld and has a filler material (5.6) in an upper weld cavity (5.5) formed by the surface spacing (5.3). Weld-coupled working cylinder assembly according to claim 1, characterized in that a lower weld zone surface (4.4) and an upper weld zone surface (5.4) form a total weld area (3.4) and that the area ratio of the lower weld zone surface (4.4) to the total weld zone surface (3.4) is 15% to 40%. Weld-coupled working cylinder assembly according to any one of the preceding claims, characterized in that the surface spacing (5.3) in the upper weld zone is 0.5 mm to 2.0 mm. Welded-coupled working cylinder assembly according to one of the preceding claims, characterized in that the lower weld zone surface (4.4) is designed as an inner circular surface or as an inner annular surface and that the upper weld zone surface (5.4) is designed as an outer annular surface that radially surrounds the lower weld zone surface (4.4). Method for producing a welded-coupled working cylinder assembly, wherein the working cylinder assembly comprises the working cylinder component (1) and the attachment component (2), comprising the following steps: a) providing the working cylinder component (1) and the attachment component (2), b) producing a lower working cylinder component weld surface (4.1) and a lower attachment component weld surface (4.2) as well as an upper working cylinder component weld surface (5.1) and an upper attachment component weld surface (5.2), wherein at least one of the upper weld surfaces (5.1, 5.2) has a recess relative to the respective lower weld surface (4.1).1, 4.2), c) positioning the working cylinder component (1) and the attachment component (2) to form a pre-assembly, producing the butt joint (4.3) of the lower weld surfaces (4.1, 4.2) and a surface gap (5.3) of the upper weld surfaces (5.1, 5.2), d) laser welding of the lower weld surfaces (4.1, 4.2) using a laser beam, producing a laser weld seam in the lower weld seam zone (4), e) hybrid welding of the upper weld surfaces (5.1, 5.2) using the laser beam and supplying a welding filler material and filling a. upper weld space (5.5) between the upper weld surfaces in the upper weld zone (5). Method for producing a weld-coupled working cylinder assembly according to claim 6, characterized in that the line energy applied in process step d) in the lower weld zone (4) with respect to a lower weld zone area (4.4) is less than the line energy applied in process step e) in the upper weld zone (5) with respect to an upper weld zone area (5.4). Method for producing a weld-coupled working cylinder assembly according to one of the preceding claims 5 or 6, characterized in that the lower weld zone area (4.4) is designed as an inner circular area or as an inner annular area and that the upper weld zone area (5.4) is designed as an outer annular area which surrounds the lower weld zone area (4.4) radially encloses, such that in process step d) a relative movement of the pre-assembly to the laser beam 6 is carried out by means of a rotation of the pre-assembly and that in process step e) a relative movement of the pre-assembly to the laser is carried out by means of a further rotation of the pre-assembly. Method for producing a weld-coupled working cylinder assembly according to one of claims 5 to 7, characterized in that process step d) and process step e) are carried out in parallel, that a relative movement of the pre-assembly along the weld seam 3) is carried out and that the laser beam 6 is radially enclosed, such that in process step d) a relative movement of the pre-assembly to the laser is carried out by means of a further rotation of the pre-assembly. Process step e) is arranged offset from the laser beam (6) according to process step d) along the direction of the relative motion.

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