CN106573330B

CN106573330B - Method for producing a shaft-hub weld connection using a welding beam

Info

Publication number: CN106573330B
Application number: CN201480080260.2A
Authority: CN
Inventors: 米夏埃尔·特奥巴尔德; 托比亚斯·耶纳
Original assignee: Festo SE and Co KG
Current assignee: Festo SE and Co KG
Priority date: 2014-10-14
Filing date: 2014-10-14
Publication date: 2019-12-20
Anticipated expiration: 2034-10-14
Also published as: DE112014007066A5; CN106573330A; WO2016058619A1

Abstract

The invention relates to a method for producing a welded connection between a shaft (4) of a shaft-hub assembly (1) and a hub (6) through which the shaft (4) passes. A weld seam extending around the shaft (4) is produced between the two components (4, 6) by means of a welding beam (26). The welding beam (26) is introduced at an irradiation position (EP) in a quadrant (32) of a Cartesian coordinate system, the x-axis of which coincides with the longitudinal axes (3, 7) of the shaft (4) and the hub (6). The irradiation position (EP) is separated from both the x-y plane (15) and the x-z plane (16) of the coordinate system. Furthermore, the orientation of the welding beam (26) during the welding process is selected such that the beam direction at the irradiation position (EP) is inclined by an irradiation angle (Wxy, Wxz) with respect to the x-y plane and/or with respect to the x-z plane. The invention also relates to a device for carrying out the method.

Description

Method for producing a shaft-hub weld connection using a welding beam

Technical Field

The invention relates to a method for producing a welded connection between a shaft of a shaft-hub assembly and a hub through which the shaft passes, wherein the longitudinal axes of the shaft and the hub define a common x-axis of a three-dimensional cartesian coordinate system, while the longitudinal axes form the intersection of an x-y plane perpendicular to the z-axis of the coordinate system and an x-z plane perpendicular to the y-axis of the coordinate system, wherein a weld seam extending around the shaft is produced by means of a welding beam entering from one axial side of the hub, which weld seam connects the hub to the shaft in a substance and substance-bonded manner. The invention also relates to a device for carrying out such a welding method.

Background

Assemblies comprising a shaft and a hub mounted on the shaft are used in many technical fields. The hub is typically an annular or sleeve-shaped body having a substantially central opening through which passes a solid or hollow rod-shaped body, referred to as a shaft. In order to save on fixing elements, the hub and the shaft are coupled together in a substance-to-substance manner by means of a welded connection. The terms "hub" and "shaft" are to be understood broadly in the sense of the present invention and are not limited in a particular physical embodiment. The field of use and the form of application of the shaft-hub assembly are also not restricted, so that in use the shaft-hub assembly may for example perform a linear movement or a rotational movement.

One area of use for the shaft-hub assembly that applicant believes is that it is of interest in the art of hydraulic drives to use the shaft-hub assembly as a piston rod-piston assembly in a hydraulically operated working cylinder. Reference may be made, for example, to EP 1503114B 1, which shows such an application, and which also discloses a method and a device, the subject of which relates to the fixation of a hub formed by a piston on a shaft formed by a piston rod.

To the best of the applicant's knowledge, the welded connection between the shaft in the shaft-hub assembly and the hub through which the shaft passes has in the past typically been implemented such that a high-energy welding beam (e.g. a laser beam) is emitted by a suitable welding device into the transition region between the shaft and the hub and the entire shaft-hub assembly is rotated. This creates a fillet weld that joins the two components of the shaft-hub assembly together in a substance-to-substance manner. In this process, the welding apparatus is adjusted such that the beam direction of the welding beam lies in a plane formed across the x-axis and an axis extending in a radial direction with respect to the x-axis, wherein the welding beam is inclined at an acute angle with respect to the x-axis. The aim is fundamentally to keep the irradiation angle of the welding beam to the x axis as small as possible in order to penetrate the producible weld seam as far as possible into the hub in the axial direction. However, due to the construction of the welding apparatus, such adjustment is limited, so that the irradiation angle is usually relatively large. This results in the weld penetrating only a short distance into the hub in the x-axis direction in the radial transition region between the shaft and the hub (which can be described as the joining region), while at the same time penetrating radially to a relatively large depth into the shaft. First, in the case of a hub that is wide in the x-axis direction, this can adversely affect the strength of the welded connection and, in some cases, can also lead to undesirable variations in the material structure of the shaft. Moreover, to obtain sufficient strength, it is often necessary to apply welds on both axial sides of the hub, which lengthens the time required for the process and increases the manufacturing costs of the shaft-hub assembly.

Disclosure of Invention

The aim of the invention is to provide measures which, while ensuring high strength, simplify the welded connection between the hub and the shaft of the shaft-hub assembly and reduce the cost thereof.

To solve this problem, according to the invention, in the aforementioned method, the welding beam is introduced into the shaft-hub assembly at an irradiation position which is located in one of the four quadrants of the cartesian coordinate system defined by the y-axis and the z-axis and is thereby separated from the x-y plane and from the x-z plane, wherein the orientation of the welding beam during the welding process is selected such that its beam direction at the irradiation position is inclined at an irradiation angle with respect to the x-y plane and/or with respect to the x-z plane.

The problem is also solved in that the device has an adjustment device which can variably adjust the distance of the irradiation position of the welding beam from the x-y plane and the x-z plane and which can variably adjust the angular orientation of the welding beam at the irradiation position relative to the x-y plane and/or relative to the x-z plane.

The measure according to the invention makes it possible to produce a weld seam in the radial joint region between the shaft and the hub, which weld seam extends very far in the direction of the x-axis or even completely through the hub, but still has only a limited radial penetration depth with respect to the shaft and the hub. The specific arrangement of the irradiation positions of the welding beam in combination with the beam directions of the welding beam being inclined with respect to the x-y plane and/or with respect to the x-z plane allows the welding process to be carried out without hindering the welding device and its orientation by the shaft of the shaft-hub assembly projecting axially from the hub. In an ideal case, when a weld is generated in the joining region between the shaft and the hub, the welding beam will enter the joining region in a beam direction parallel to the x-axis, which is however not possible with conventional welding methods due to the size of the welding apparatus generating and guiding the welding beam. The welding device will collide with the shaft. By means of the measures according to the invention, it is possible to obtain a welding result without the risk of collision between the welding device and the shaft, which corresponds to or at least very close to the ideal welding result. The corresponding selection of the irradiation position and of the at least one irradiation angle makes it possible to obtain an axially continuous weld seam, i.e. a weld seam which extends in the x-axis direction through the entire hub, so that a high joining strength is obtained, and furthermore, for carrying out the welding process, only one side, i.e. only one of the two axial sides of the hub, is required for welding. This avoids the drawback of having to clamp the shaft-hub assembly multiple times during welding and minimizes the risk of warping of the parts through thermal effects. Preferably to a single weld, which reduces the risk of heat input and structural changes of the materials of the parts to be joined, and also avoids the problem of remelting of the weld already produced. In addition, the problem that the shaft and the hub may not be completely welded together in the axially central region of the hub is eliminated.

Advantageous further developments of the invention are described in the dependent claims.

Advantageously, the welding beam is oriented during the welding process such that its beam direction at the irradiation position is inclined both with respect to the x-y plane and with respect to the x-z plane. Thus, the beam direction has a first illumination angle relative to the x-y plane at an illumination position and a second illumination angle relative to the x-z plane at the same illumination position. Thus, the beam direction is neither parallel to the x-y plane nor the x-z plane. In this way, the welding device emitting the welding beam can be optimally arranged close to the axis, while still obtaining the above-mentioned welding results, mainly due to the fact that the irradiation position is spaced apart from the x-y plane and additionally from the x-z plane. The irradiation location is the location on the shaft-hub assembly where the welding beam is directed or penetrated into the shaft-hub assembly.

The aforementioned angular position of the beam direction advantageously results in the welding beam being oriented such that its distance from the x-y plane and the x-z plane increases with increasing axial distance from the hub.

An advantageous possibility is also to select the orientation of the welding beam during the welding process such that on the one hand its beam direction extends at least substantially parallel (and preferably completely parallel) to the x-z plane, while on the other hand a certain inclination with respect to the x-y plane is obtained at the irradiation position. Thereby, advantageously, a measure is taken to select the distance of the irradiation position from the x-z plane to at least substantially correspond to the radius of the axis. In this way, the welding beam can be directed obliquely from the outside into a plane parallel to the x-axis in the shaft-hub assembly, even if the beam direction deviates from the axial direction of the x-axis in this case. The distance of the irradiation position from the x-z plane may also be at least slightly offset by the radius of the shaft in order to ensure that the weld seam produced does form a reliable weld joint between the hub and the shaft over the entire length of the hub in the x-direction.

During the welding process, the selected irradiation angle relative to the x-z plane is preferably in the range between 0 ° and 15 °, including the limits of said range.

During the welding process, the irradiation angle with respect to the x-y plane is advantageously selected in the range between 30 ° and 60 °, whereby the limits of this range are also included in the specified range.

It is particularly advantageous to combine the preferred range of illumination angles with respect to the x-y plane with the preferred range of illumination angles selected with respect to the x-z plane.

The irradiation position at which the welding beam is introduced into the shaft-hub assembly is advantageously located on an axial end face of the hub oriented in the axial direction of the x-axis. Thus, during the welding process, the welding beam enters the shaft-hub assembly on this end face of the hub.

Another advantageous measure involves selecting the irradiation position such that the irradiation position is located on the outer periphery of the shaft and at an axial distance from the hub. In this case, the welding beam enters the shaft first and then cooperates with the hub.

The irradiation position may be located in a radial transition region between the shaft and the hub. However, it is believed to be more advantageous for the radial distance of the irradiation position with respect to the x-axis to be greater than the radius of the axis.

Advantageously, the welding apparatus is kept in a constant position during the welding process, while the shaft-hub assembly rotates unidirectionally, and advantageously at a constant speed, around the x-axis. In this way, a continuous circumferential weld seam extending concentrically around the x-axis can be generated in a particularly simple manner.

The measure according to the invention, of course, makes it possible to weld the hub supported on the shaft to the shaft as before from opposite axial end faces by means of two weld seams. Such a bidirectional or double-sided welding is particularly suitable if the axial structural length of the hub is relatively large. However, especially for shorter hubs, it is advantageous to generate only a single weld seam, which advantageously penetrates the hub completely around its entire circumference in the axial direction of the hub to form a welded connection between the shaft and the hub.

The weld seam running axially through the hub advantageously terminates with an annular end face concentric to the x axis in the region of two opposite axial end faces of the hub. As has been found, with the method according to the invention, it is possible to obtain welding results in which both annular end faces have a concave cross-sectional profile, wherein cross-section is taken as viewed in a cross-sectional plane formed across the x-axis and a radial axis with respect to the x-axis.

With regard to the irradiation angle relative to the x-y plane, the penetration depth of the welding beam or the welding depth in the axial direction of the x-axis can be adjusted as desired by changing the angle, whereby the narrower the irradiation angle selected relative to the x-y plane, the greater the axial welding depth.

The curvature of the weld relative to the x-axis direction can be affected by changes in the angle of illumination presented relative to the x-z plane. The greater the angle of illumination, the greater the curvature of the weld in a plane formed across the x-axis and a radial axis perpendicular thereto.

If the weld ends in an end face which is concave in cross-section, i.e. which in practice has a radius, this results in a gentle transition between the parts to be welded, which minimizes the problem of notch effects.

The method may be considered particularly advantageous in the production of piston rod-piston assemblies forming part of hydraulic working cylinders. Such a hydraulic working cylinder preferably comprises a cylinder housing with two end walls, wherein the piston in the piston rod-piston assembly is mounted displaceable in a linear direction inside the cylinder housing, and the piston rod extends in an axial direction and is slidably displaceable through one end wall of the cylinder housing to the outside. The piston divides the interior chamber of the cylinder housing into two working chambers, at least one of which may be acted upon by pressurized hydraulic fluid such that a compressive force acts on the piston to cause linear movement of the piston rod-piston assembly relative to the cylinder housing. Such working cylinders are highly versatile in use and have a wide range of applications, particularly in the automation technology industry.

The welding process is carried out by means of a welding beam, which advantageously does not require any additional welding material to be supplied. In this respect, it is particularly advantageous to use a laser welding method, in which a laser beam is used as the welding beam. In principle, however, the invention can be used advantageously with all beam welding methods, for example also with electron beam welding methods.

If the device for carrying out the welding method has an adjusting device which makes it possible to vary the irradiation position and/or one or both irradiation angles, it is advantageous if the same welding device is used for differently configured piston rod-piston assemblies by varying the adjusting parameters. Moreover, the adjustment considered optimal can be performed individually for each piston rod-piston assembly to be welded.

Drawings

The invention will be explained in more detail below with reference to the drawings, in which:

fig. 1 shows a shaft-hub assembly produced by means of the welding method according to the invention in longitudinal section along a section plane formed across the x-axis and z-axis of a cartesian coordinate system, wherein the weld seam of the welded connection can be seen in the radial transition region between shaft and hub,

figure 2 shows a front view of the shaft-hub assembly in the axial direction of the x-axis, seen in the direction indicated by arrow II in figure 1, during the execution of the welding method,

fig. 3 shows a top view of the arrangement in fig. 2 seen in the direction indicated by arrow III during the execution of the welding method, an

Fig. 4 shows a side view of the shaft-hub assembly seen in the direction indicated by arrow IV in fig. 2 during the execution of the welding method.

Detailed Description

In fig. 1a shaft-hub assembly 1 is shown, which shaft-hub assembly 1 is joined with a welded connection 2 to form an integral unit. The shaft-hub assembly 1 includes a shaft 4 having a longitudinal axis 3, and an annular or sleeve-shaped hub 6 having a longitudinal axis 7 and an axial bore 5.

The hub 6 is coaxially fitted and in particular plugged onto the shaft 4. Thereby, the shaft 4 passes through the opening 5 of the hub 6. At least in the longitudinal section of the shaft 4 provided with the hub 6, the outer diameter of the shaft 4 at least substantially corresponds to the inner diameter of the hub 6. The hub 6 can be mounted on the shaft 4 with a slight play or also with a slight radial pretension. The two longitudinal axes 3 and 7 coincide in the shaft-hub assembly 1.

At least in the section occupied by the hub 6 (hereinafter, referred to as the mounting section 8), the shaft 4 preferably has a circular outer contour, in particular a cylindrical radially outer peripheral surface 12. Advantageously, the hub 6 has, in the region of its aperture 5, a radially inner peripheral surface 13, which inner peripheral surface 13 is also of circular profile, advantageously of cylindrical form.

The region in which the radially outer circumferential surface 12 of the shaft 4 and the radially inner circumferential surface 13 of the hub 6 are arranged radially opposite one another is also referred to below as a joint region 14, in which joint region 14 the welded connection 2 formed by the substance and the substance connection between the hub 6 and the shaft 4 is formed.

The shaft 4 and the hub 6 consist, for example, of metal, in particular of steel, at least in the region of the portions forming the welded connection 2. However, other materials are also possible, for example a plastic material or additionally a composite material.

To simplify the explanation of the structure of the shaft-hub assembly 1 and of the execution of the welding method according to the invention, reference is made to a cartesian coordinate system comprising an x-axis, a y-axis perpendicular thereto and a z-axis perpendicular to both the x-axis and the y-axis. In FIG. 1, the x-axis and z-axis are shown in dashed lines; they are located in the drawing. The y-axis runs through the intersection of the x-axis and the z-axis and extends perpendicular to the plane of the drawing.

The x-axis coincides with the two longitudinal axes 3, 7. Thus, the two longitudinal axes 3, 7 together define the x-axis of a three-dimensional cartesian coordinate system. The x-axis also defines the line of intersection of an x-y plane 15 perpendicular to the z-axis of the coordinate system and an x-z plane 16 perpendicular to the y-axis of the coordinate system. An x-y plane 15 is formed across the x-axis and the y-axis, while an x-z plane 16 is formed across the x-axis and the z-axis.

Fig. 2 to 4 show the arrangement of the shaft-hub assembly 1 in connection with the execution of the welding method for producing the welded connection 2. The same reference numerals and letters are used throughout the drawings to designate corresponding parts.

In addition to the shaft-hub assembly 1, fig. 2 to 4 schematically show components of a welding device 17 which are particularly suitable for producing the welded connection 2. With the welding device 17, a beam welding method can be carried out in order to produce the weld connection 2.

Advantageously, the welding connection 2 comprises only a single weld seam 18, which weld seam 18 can be generated by or by the welding device 17. Advantageously, the weld 18 is located in the joining region 14 and forms a local material fusion between the material of the hub 6 and the shaft 4.

The weld 18 is preferably annular in form and is arranged concentrically with the x-axis. Advantageously, the weld 18 is formed as a continuous annular weld 18 extending in the circumferential direction of the x-axis. The weld seam 18 to be produced in this way is shown in fig. 2 by a dot-dash line.

It is also advantageous if only a single weld seam 18 is used for the welded connection 2, as is the case in the exemplary embodiment. In addition, fig. 1 shows an advantageous embodiment of the weld 18 extending around the x-axis, wherein the weld 18 extends through the entire axial length of the hub 6, just around the x-axis. In this way, the hub 6 is welded to the shaft 4 over its entire axial length. This results in a particularly stable joint.

The hub 6 has a first axial end face 22a in the region of the first axial side 22. The hub 6 has a second end face 23a, which is oriented axially opposite the first axial end face 22a, in the region of a second axial side 23 opposite the first axial side 22. The substantially annular weld seam 18 has an axial length in the direction of the x axis which terminates with a first end face 24 and a second end face 25 in the region of the two end faces 22a, 23a of the hub 6. The first end face 24 is located in the region of the first axial side 22 of the hub 6, while the second end face 25 of the weld seam 18 is arranged in the region of the second axial side 23 of the hub 6. The two end faces 24, 25 of the weld 18 are annular in form and are oriented concentrically to the x-axis.

The welding device 17 comprises a welding beam generating device (not shown), by means of which an energy-containing welding beam 26, which is illustrated in fig. 2 to 4 by means of a thicker line, can be generated. For example, the welding beam generating device is adapted to generate a laser beam such that the welding beam 26 is a laser beam. However, the invention can also be realized with a welding device 17, which welding device 17 can be realized with a different type of welding beam 26, for example an electron beam.

The welding device 17 has a welding beam output 17a, from which a welding beam 26 generated by the welding beam generating device emerges. To carry out the welding method, the welding beam output device 17a is arranged in the region of the outer periphery of the shaft-hub assembly 1, so that the welding beam 26 irradiates the irradiation location EP on the outer surface of the shaft-hub assembly 1 and into the shaft-hub assembly 1.

Advantageously, the welding device 17 is equipped with an adjusting device 17b which enables a variable adjustment of the position and/or orientation of the welding beam output device 17a in order to variably set the position of the irradiation position EP and the orientation of the welding beam 26 in a cartesian coordinate system as required.

To generate the weld 18, the welding beam 26 is set to illuminate the illumination position EP on the shaft-hub assembly 1 while the entire shaft-hub assembly 1 is rotated about the x-axis. The rotational movement of the shaft-hub assembly 1 is indicated by arrow 27. The axis of rotation of the shaft-hub assembly 1 thus coincides with the x-axis.

The rotary movement 27 is generated in particular as a unidirectional rotary movement, that is to say the shaft-hub assembly 1 rotates during the welding in only one direction of rotation. The welding beam 26 is thus kept constantly directed at the irradiation position EP, whose position in the cartesian coordinate system is also kept constant, while its relative position with respect to the shaft-hub assembly 1 changes. In this way, the energy input to form the weld connection moves in the circumferential direction of the x-axis around the x-axis until finally an annular continuous weld 18 is formed. Advantageously, the angular orientation of the welding beam 26 remains constant during the welding process and also during the rotational movement 27. Of course, during the welding process, i.e. during the rotation of the shaft-hub assembly 1, it is fully possible to adjust the orientation of the welding beam 26 and the position of the irradiation position EP.

The rotational movement 27 of the shaft-hub assembly 1 can be realized by the rotating means 17c of the welding device 17. The rotating means 17c comprise, for example, clamping means 28 for releasably clamping the shaft-hub assembly 1 in place during the welding process, wherein a rotary drive means (not shown) is associated with the clamping means 28 such that a rotary motion 27 can be generated. Preferably, the clamping device 28 clamps the shaft 4.

During the welding process, the welding device 17 or the welding beam output device 17a is arranged such that the welding beam 26 projects from one of the two shaft sides 22 or 23 of the hub 6 into the shaft-hub assembly 1. For example, the welding beam 26 impinges directly into the hub 6 in the region of the first axial side 22 of the hub 6.

During the execution of the welding method, the welding beam 26 is directed towards the shaft-hub assembly 1 such that the irradiation position EP is located in one of the four quadrants of the cartesian coordinate system defined by the y-axis and the z-axis. This quadrant of the cartesian coordinate system is referred to below as the illumination quadrant 32. The illumination quadrant 32 in which the illumination position EP is located can best be seen in fig. 2.

The location of the illumination location EP is also selected such that the illumination location EP within the illumination quadrant 32 is separated from both the x-y plane 15 and the x-z plane 16. The distance from the x-y plane is measured in the axial direction of the z-axis and is denoted as Az in the figure. The distance from the x-z plane is measured in the axial direction of the y-axis and is denoted as Ay in the drawing.

The specific spatial orientation of the welding beam 26 is also particularly relevant for the execution of the welding method. The orientation is selected such that the beam direction of welding beam 26 at irradiation position EP is tilted by an irradiation angle Wxy with respect to x-y plane 15 and/or by an irradiation angle Wxz with respect to x-z plane 16.

Preferably, and as is realized in the exemplary embodiment, the beam direction of welding beam 26 forms an illumination angle Wxy with respect to x-y plane 15 and an illumination angle Wxz with respect to x-z plane 16, wherein both illumination angles are each greater than zero. The welding beam 26 is thus tilted both with respect to the x-y plane 15 and with respect to the x-z plane 16. Starting from the irradiation position EP, due to the oblique orientation, the distance of the welding beam 26 from the x-y plane 15 and from the x-z plane 16 increases as the axial distance from the hub 6 in the direction of the welding beam output device 17a within the irradiation quadrant 32 increases.

In a variant (not shown) of carrying out the welding method, the orientation of the welding beam 26 during the welding process is selected such that, on the one hand, its beam direction extends at least substantially parallel to the x-z plane 16 and, on the other hand, it is inclined by an irradiation angle Wxy at the irradiation position EP with respect to the x-y plane 15. In this case, the illumination angle Wxy with respect to the x-y plane 15 is thus greater than zero, while the illumination angle Wxz with respect to the x-z plane 16 is at least approximately equal to zero. In this connection, it is particularly advantageous if the distance Ay of the irradiation position EP measured with respect to the x-z plane at least substantially corresponds to the dimension of the axial radius.

As has been found, particularly advantageous welding results are achieved with a selected irradiation angle Wxz in the range of 0 ° to 15 ° relative to the x-z plane 16, while at the same time the irradiation angle Wxy relative to the x-y plane 15 is in the range of 30 ° to 60 °. The smaller the selected irradiation angle Wxy, the deeper the penetration of the weld seam 18 in the x-axis direction into the shaft-hub assembly 1 in the joining region 14. In particular, if the weld according to fig. 1 is considered in a cross-section formed across the x-axis and the z-axis, the variation in the illumination angle Wxz affects the curvature of the weld 18.

It is particularly advantageous to arrange the irradiation position EP directly on one axial end face of the hub 6 oriented in the x-axis direction, as is the case in the exemplary embodiment. In this case, the irradiation position EP is located on the first axial end face 22a of the hub 6 associated with the first axial side 22.

The irradiation position EP for the welding beam 26 can be located directly in the radial transition region between the shaft 4 and the hub 6.

It is considered particularly advantageous that the irradiation position EP within the irradiation quadrant 32 is located at a radial distance outside the radially outer peripheral surface of the shaft 4. This is very well illustrated in fig. 2. Fig. 2 also shows the application of the welding method, wherein the irradiation position EP is at a distance Ay from the x-z plane 16 which at least substantially corresponds to the radius of the axis 4. At the same time, the distance Az of the irradiation position EP measured with respect to the x-y plane 15 is greater than zero, but less than the radius of the axis 4.

The adjustment means 17b make it possible to adjust the distance and angle parameters as desired. In this way, there is the possibility of influencing the welding results individually, and of welding together shaft-hub assemblies 1 of different sizes using the same welding device 17.

In particular, by a corresponding adjustment of the welding beam 26, the form of the weld seam 18 can also be influenced in such a way that it has a concave cross-sectional profile in the region of its two end faces 24, 25. This is the case in the exemplary embodiment according to fig. 1. This is the profile that would be visible if the shaft-hub assembly 1 were viewed in a cross-sectional plane formed across the x-axis and z-axis. The concave profile termination of the weld seam 18 reduces the notch stress, thereby ensuring a further increase in the strength of the welded connection 2.

The shaft-hub assembly 1 shown in the figures is preferably a piston rod-piston assembly 1a of a hydraulic working cylinder 33, which is only schematically shown. Thereby, the shaft 4 is formed by the piston rod 4a, and the hub 6 is formed by the piston 6a of this cylinder 33. The working cylinder 33 has a schematically illustrated cylinder housing 34, by means of which the piston 6a of the piston rod-piston assembly 1a is accommodated in a slidably displaceable manner in the cylinder housing 34 in the finished, welded-together state, while the piston rod 4a projects from an end face of the cylinder housing 34, in order to enable power take-off. The inner chamber of the cylinder housing 34 may be pressurized by hydraulic fluid, in particular compressed air, at a positive pressure in order to cause a linear movement of the piston rod-piston assembly 1a relative to the cylinder housing 34. It will be appreciated that in this case the piston rod 4a has a greater length than presented in the figures. The illustration in the figures is only intended to schematically show the structure of the shaft-hub assembly 1. If the hub 6 is designed as a piston 6a, the piston 6a is in most cases also equipped with at least one seal, by means of which the piston 6a slides against the inner periphery of the cylinder housing 34.

The measure according to the invention is not limited to the field of hydraulic working cylinders, but can be used in connection with shaft-hub assemblies of any design.

Claims

1. Method for producing a welded connection between a shaft (4) of a shaft-hub assembly (1) and a hub (6) through which the shaft (4) passes, wherein longitudinal axes (3, 7) of the shaft (4) and the hub (6) define a common x-axis of a three-dimensional cartesian coordinate system, while the longitudinal axes (3, 7) form an intersection of an x-y plane perpendicular to a z-axis of the coordinate system and an x-z plane perpendicular to a y-axis of the coordinate system, wherein a weld seam (18) extending around the shaft (4) is produced by a welding beam (26) entering from one axial side (22) of the hub (6), the weld seam (18) connecting the hub (6) with the shaft (4) in a substance-and substance-combination,

characterized in that the welding beam (26) is introduced into the shaft-hub assembly (1) at an irradiation position (EP) which is located in one quadrant (32) of the four quadrants of the cartesian coordinate system defined by the y-axis and the z-axis and is thereby separated from the x-y plane and from the x-z plane, wherein the orientation of the welding beam (26) during the welding process is selected such that the beam direction of the welding beam (26) at the irradiation position (EP) is inclined with respect to the x-y plane and with respect to the x-z plane at an irradiation angle (Wxy, Wxz) each;

wherein an angle of illumination (Wxy, Wxz) relative to an x-y plane and relative to an x-z plane, respectively, is greater than zero, the welding beam (26) thereby being tilted relative to both the x-y plane and relative to the x-z plane;

wherein the irradiation position (EP) is located on an axial end face (22a) of the hub (6) facing in an axial direction of the x-axis, and a radial distance of the irradiation position (EP) with respect to the x-axis is greater than a radius of the shaft (4).

2. Method according to claim 1, characterized in that the irradiation angle (Wxy) relative to the x-y plane (16) selected during the welding process is in the range of 30 ° to 60 °.

3. Method according to one of claims 1 to 2, characterized in that the distance (Ay) of the irradiation position (EP) from the x-z plane substantially corresponds to the radius of the axis (4) and the distance (Az) of the irradiation position (EP) from the x-y plane (15) is greater than zero and smaller than the radius of the axis (4).

4. Method according to one of claims 1 to 2, characterized in that during the generation of the weld seam (18) the shaft-hub assembly (1) rotates unidirectionally, and advantageously continuously, around the x-axis.

5. Method according to one of claims 1 to 2, characterized in that the weld seam (18) is formed as a continuous annular weld seam (18) extending concentrically around the x-axis.

6. Method according to one of claims 1 to 2, characterized in that only a single weld seam (18) is generated which penetrates completely through the hub in the axial direction of the x-axis around the entire circumference of the hub to form a welded connection between the shaft (4) and the hub (6).

7. Method according to claim 6, characterized in that the weld seam (18) ends with annular end faces (24, 25) concentric to the x-axis in the region of the two axial sides (22, 23) of the hub (6), wherein the two annular end faces (24, 25) of the weld seam (18) each have a concave cross-sectional profile.

8. Method according to one of claims 1 to 2, characterized in that the shaft-hub assembly (1) is a piston rod-piston assembly (1a) for a hydraulic working cylinder (33), wherein the shaft (4) is formed by the piston rod (4a) of the piston rod-piston assembly (1a) and the hub (6) is formed by the piston (6a) of the piston rod-piston assembly (1 a).

9. Method according to one of claims 1 to 2, characterized in that a laser beam or an electron beam is used as welding beam (26) to generate the welded connection.