Working cylinder

Abstract

The invention relates to a working cylinder comprising a cylinder (11) and a piston unit (12), characterized in that the cylinder (11) has a bottom-side joint head (20) which has a bottom-side joint head main body (21) and a bottom-side joint bearing (22); in that the bottom-side joint head main body (21) is in the form of an annular body and has a bottom-side concentric receiving bore (23), in which the bottom-side joint bearing (22) is received, and also has a bottom-side radial annular body outer lateral surface (24); in that the bottom closure part (15) has a bottom closure part shaped portion (15.1) which is formed as a monolithic portion of the bottom closure part (15) and which rises axially above an outer bottom closure part covering surface (15.2) and which has a projection-like basic shape that follows a radius; in that the bottom closure part shaped portion (15.1) has a concave indentation which forms a bottom-side receiving portion (15.3) which has a bottom-side radial inner lateral surface (15.4) corresponding to the bottom-side radial annular body outer lateral surface (24); and in that the bottom-side joint head main body (21) is welded, at a bottom-side radial annular body outer lateral partial surface (25), to the bottom closure part (15), at the bottom-side radial inner lateral surface (15.4), by means of a bottom-side annular-segment-shaped laser weld seam (26).

Description

[0001] The invention relates to a working cylinder with coupling sections for a hinged coupling with a device to be actuated.

[0002] It is known from the prior art to couple working cylinders with devices to be actuated via connection modules for the purpose of force transmission. In this context, rod ends are particularly well-known as connection modules from the prior art.

[0003] Rod ends are manufactured primarily as flame-cut or forged parts and accommodate a spherical bearing in a joint eye, which can have different degrees of freedom in order to couple the working cylinder free from bending stresses.

[0004] For coupling to a bottom closure component, it is known in the art to connect the rod end by means of MAG welding. However, this method requires not only the size but also the shape of the rod ends to be determined based on the working cylinder being coupled, thus increasing their cost. Typically, the rod end is provided with a straight outer contour section that is welded flat onto the top surface of the bottom closure component. To withstand the high forces, the MAG weld is generously dimensioned. The weld bead in the fillet, which can be up to 15 mm thick, requires a corresponding allowance relative to the distance of the outer contour section from the so-called joint eye, in order to ensure sufficient free movement around the joint eye.Due to the large heat input during welding, temperature-sensitive components, such as spherical bearings in particular, may be disadvantageously mounted only after welding, or a material allowance of at least 30% of the mass must be provided at the rod end to dissipate the heat sufficiently.

[0005] For coupling a rod end to a piston rod, a screw connection is known from the prior art. This requires, firstly, an external thread to be milled into the piston rod and, secondly, the rod end to be prepared with a blind hole and an internal thread. Besides the considerable effort required to produce the threaded pair, a minimum thread length must also be considered, which may be further increased by additional length allowances for the milled wrench flats intended for applying torque or for counterholding during tightening.

[0006] Furthermore, the prior art, specifically CN 105 422 545 A, describes an alternative solution for coupling a rod end to a working cylinder using a pin and a fiber-reinforced bushing. A disadvantage of this solution is its lower load-bearing capacity, particularly in the case of a tension cylinder.

[0007] The object of the invention is to provide a working cylinder that can be coupled by means of a ball joint, which requires little installation space and can be manufactured with reduced material usage and time expenditure.

[0008] The problem is solved by the features listed in claim 1 and, according to a further aspect of the invention, by the features listed in claim 7.

[0009] Preferred further training courses result from the sub-requirements.

[0010] The working cylinder according to the invention comprises a cylinder and a piston unit as basic elements and is characterized by a coupling section with a ball joint designed in a special way.

[0011] The cylinder of the working cylinder according to the invention comprises, in a manner known per se, a cylinder tube, a first closing part and a second closing part.

[0012] The cylinder tube has two opposing cylinder tube ends. These two opposing cylinder tube ends are subsequently referred to as the first cylinder tube end and the second cylinder tube end, and collectively as the cylinder tube ends.

[0013] The first locking element is located at the first end of the cylinder tube, and the second locking element is located at the second end of the cylinder tube. Hereinafter, the first and second locking elements will be referred to collectively as the locking elements. The first locking element is designed as a guide locking element, and the second locking element as a bottom locking element.

[0014] The cylinder tube and the closure elements attached to it form a cylinder interior. For this purpose, the two closure elements are designed to be pressure-tightly connected to the respective cylinder tube ends. To join them, the two closure elements are preferably laser-welded to the cylinder tube along their common circumferential contact surface.

[0015] The piston unit forms at least one working chamber within the cylinder interior. The piston unit is preferably designed as an assembly consisting of a piston and piston rod, with the piston rod sliding through the guide breech element. However, the piston unit can also be, for example, a plunger piston or a piston unit of a synchronous cylinder. The working cylinder according to the invention can also be of other types, in particular a differential working cylinder or a tension cylinder. Preferably, it is a hydraulic cylinder, but this is not the only possible design.

[0016] The piston assembly has an outer end section. The outer end section is understood to be the distal head section of the piston assembly, preferably the piston rod, located outside the cylinder interior. In the case of a plunger cylinder, this is the distal head of the plunger piston.

[0017] The working cylinder according to the invention is also characterized by a coupling section designed in a special way.

[0018] In the context of the present invention, a coupling section is understood to be the part of the working cylinder that is connected to a device to be actuated, for example, an excavator arm, and through which the forces provided by the working cylinder are transmitted or the forces emanating from the device to be actuated are received. The device to be actuated itself is not part of the working cylinder according to the invention. It merely provides the functional context for the working cylinder according to the invention. Typically, two opposing coupling sections are arranged on the working cylinder, with at least one coupling section being designed according to the invention.

[0019] For this purpose, the working cylinder according to the first independent claim has a bottom-side ball joint according to the invention.

[0020] The bottom-side rod end comprises a bottom-side rod end body and a spherical bearing arranged therein. The spherical bearing serves to couple the working cylinder to a device to be actuated in a friction-optimized manner and without moment in at least one rotational degree of freedom by means of a coupling bolt.

[0021] According to the invention, the bottom-side rod end body is designed as a ring body. A ring body is understood to be a rotationally symmetrical component that, unlike flame-cut or forged parts known from the prior art, can advantageously be provided with high precision by simple turning. Preferably, the ring body has a substantially hollow cylindrical shape.

[0022] The bottom-side joint head body has a concentric receiving bore in which the joint bearing is received.

[0023] Furthermore, the bottom-side joint head body has an annular outer surface. This extends circumferentially in a radial direction on the outer surface of the annular body.

[0024] According to the invention, the bottom closure part of the working cylinder has a bottom closure part shaped in a special way.

[0025] The base closure component section is designed as a monolithic segment of the base closure component and is primarily produced by milling. The base closure component section rises from the outer surface of the base closure component above the plane it spans in an axial distal direction. The base closure component section has a radius-following, web-like basic shape. A web-like basic shape is understood to be an essentially prismatic body whose base and top surfaces are arranged transversely to the surface of the base closure component. The radius-following basic shape is defined as a concave indentation in the essentially prismatic basic shape of the base closure component section. At the concave indentation, a concavely curved surface exists, which geometrically forms a segment of a cylindrical surface and is subsequently referred to as the bottom-side radial inner surface.

[0026] The concave recess forms a receiving section. This receiving section is shaped such that it has a radial inner surface corresponding to the radial outer surface of the ring body. The cylindrical shape of the receiving section advantageously allows for a flat receiving surface of the rod end body. The section of the radial outer surface of the ring body that rests flat against the radial inner surface of the concave receiving section of the bottom closure part is hereinafter also referred to as the outer surface of the ring body.

[0027] This surface contact advantageously enables a high force transmission of compressive forces, such as those that occur particularly when the working cylinder is extended. The corresponding surfaces simultaneously provide a partial positive locking mechanism for positioning the rod end body and the bottom closure part, counteracting rotation and tilting of the rod end body.

[0028] The bottom-side rod end body is welded to the bottom end cap on the radial inner surface of the annular body by means of a bottom-side laser ring segment weld. The full-surface welding of the rod end body and bottom end cap on the corresponding surfaces creates a reliable, material-bonded connection between the two parts and enables the transmission of high tensile forces, such as those encountered during the initial operating phase of the working cylinder.

[0029] The solution according to the invention for providing a articulated working cylinder has, in particular, the following advantages.

[0030] A surprising solution was achieved by combining a surface fit of corresponding cylinder shell surfaces with a precise laser ring segment weld, thus easily overcoming the long-standing disadvantages of prior art solutions for manufacturing rod ends. Neither complex thread milling nor the disadvantages of imprecise, high-material-deposition, and heat-generating MAG welding occur.

[0031] Furthermore, the bottom closure component can be advantageously produced as a turned part in a particularly simple and cost-effective manner. Due to its simple geometry, the bottom closure component's form section can also be manufactured using standard milling machines during the production of the bottom closure component, employing the same technology as the bottom closure component itself, without requiring an additional machining station. This results in a significant advantage in terms of manufacturing effort and associated production costs. The low heat input of the laser welding process allows for small heat-affected zones, thus preventing thermal damage or deformation of the bottom closure component or the rod end body.

[0032] In particular, laser welding according to the invention is also possible with previously inserted sensitive components such as polymer seals or the like.

[0033] Furthermore, by overcoming the disadvantages of the prior art, such as those encountered with MAG welding, laser welding of the rod end body to the end cap can also be performed on an already assembled spherical bearing. This makes it possible to mass-produce the rod end as a finished assembly consisting of the rod end body and spherical bearing with high precision before welding. This results in advantageously higher accuracy and tighter tolerances.

[0034] In an advantageous further development, the working cylinder is characterized in that a bottom-side pressure medium connection bore is arranged at least section by section in the bottom closure part form section.

[0035] Advantageously, this further development allows the installation space provided by the bottom closure section to be used simultaneously for the arrangement of the pressure medium connection bore. By utilizing the axially distal elevation of the bottom closure section, the overall length of the working cylinder can thus be reduced while maintaining the same stroke length.

[0036] Advantageously, this creates functional integration by means of the bottom closure part mold section, in that the bottom closure part mold section firstly receives the ball head in a force-transmitting manner and secondly creates a space axially distal beyond the bottom closure cover surface for receiving the pressure medium connection bore.

[0037] In a special variant based on this, the working cylinder is characterized by the fact that the bottom-side pressure medium connection bore crosses at least partially distally a transverse plane spanned by a vertex line of the receiving section to a longitudinal axis.

[0038] The vertex line of the receiving section is the point where the bottom closure part forming section has the smallest elevation above the bottom closure part cover surface and, in a mounted state, the ball joint base body extends furthest in the proximal direction.

[0039] The pressure medium connection can therefore be positioned in the bottom closure section in an area with maximum material coverage and at the same time very far distally. This achieves maximum bending stiffness of the connection. This advantageously allows for a significant reduction in overall length without affecting the stroke length.

[0040] According to a further advantageous embodiment, the working cylinder is characterized in that it has a rod-side articulated joint. This forms the rod-side articulated connection of the working cylinder to a device to be actuated.

[0041] The rod-side rod end also has a rod end body – hereinafter referred to as the rod-side rod end body – and a rod bearing – hereinafter referred to as the rod-side rod bearing. The descriptions of the bottom-side rod end and its arrangement on the working cylinder therefore also apply accordingly to the rod-side rod end, unless otherwise specified in the following description sections.

[0042] The rod-side joint head body is also designed as a ring body. It has a rod-side concentric receiving bore. The rod-side spherical bearing is received in this bore. Like the bottom-side joint head body, the rod-side joint head body thus also has an essentially hollow cylindrical shape. The joint head body further features a rod-side radial outer ring surface.

[0043] The piston unit has a rod-side shaped section at the outer end section.

[0044] The rod-side forming section corresponds to the bottom closure section, taking into account the rod-side characteristics. The rod-side forming section is preferably machined from the cylindrical base form of the outer end section of the piston unit by milling. It is then formed as a monolithic section of the piston unit. Accordingly, the rod-side forming section rises axially distally beyond the cylindrical section of the piston unit and has a web-like base form that follows the radius. The rod-side forming section has a concave indentation that forms a rod-side receiving section. Furthermore, the rod-side receiving section has a radial inner surface that corresponds to the radial outer surface of the annular body.

[0045] The rod-side forming section creates an exact receiving counter-form in diameter and preferably also in width to the outer surface of the rod end body. The length of the rod-side receiving section is preferably limited by the outer diameter of the piston rod.

[0046] For the positive-locking connection of the rod-side forming section with the rod-side rod head base body, the latter is welded to the piston unit on the rod-side radial inner surface by means of a rod-side laser ring segment weld seam on a rod-side radial outer surface of the rod-side radial outer surface of the rod-side radial ring body.

[0047] According to a particularly advantageous further development, the working cylinder with bottom-side and rod-side rod head is characterized in that the bottom-side rod head base body and the rod-side rod head base body are designed as structurally identical components.

[0048] The production of the rod ends can be streamlined to a significant advantage. Furthermore, considerable benefits arise for the manufacturing logistics of the working cylinder, as there is no need to consider different rod ends for the bottom and rod ends. Combined with the low thermal stress resulting from laser ring segment welding, it is possible to manufacture the rod ends as a complete assembly consisting of the base body and spherical bearing in large quantities and with high quality.

[0049] Furthermore, the invention offers the advantage that the rod ends can be manufactured in graduated sizes without specific manufacturer requirements, and that for adaptation only the bottom closure part forming section or the rod-side forming section needs to be milled according to the respective size of the rod ends available in large quantities.

[0050] According to a further advantageous embodiment, the working cylinder is characterized in that the bottom-side laser ring segment weld or the rod-side laser ring segment weld is designed as a double-sided weld.

[0051] This has the advantage of increasing stability while simultaneously reducing thermal stress, because the applied linear energy is distributed over time.

[0052] Another aspect of the invention relates, according to the dependent independent claim, to a working cylinder which has a rod end according to the invention only on the rod side.

[0053] The basic structure of the working cylinder, with respect to the cylinder, the cylinder tube, the sealing elements, and the piston unit, corresponds to the working cylinder according to the main claim, so that the descriptions contained therein also apply accordingly to the working cylinder according to the dependent independent claim described herein. Furthermore, with regard to the rod-side joint head and the design of the rod-side molded section at the outer end section of the piston unit, the descriptions in the dependent claim for the additional rod-side joint head apply accordingly.

[0054] The invention is described as an embodiment by reference to Fig. 1 Schematic sectional view of the working cylinder. Fig. 2 Schematic side view of the piston rod. Fig. 3 Schematic view of the piston rod-side molded section with the ring body. Fig. 4 Schematic side view of the working cylinder. Fig. 5 Schematic sectional view of the bottom section of the working cylinder. explained in more detail.

[0055] In this context, identical reference symbols in different figures refer to the same features or components. These reference symbols are used in the description even if they are not shown in the figure in question.

[0056] Fig. 1 shows a schematic sectional view of an exemplary embodiment of the working cylinder.

[0057] Its basic components consist of a cylinder 11 and a piston unit 12. The cylinder tube 13 is closed with a guide closure part 14 and a bottom closure part 15, thus forming a cylinder interior 16.

[0058] In this embodiment, the working cylinder has a ball joint 20, 30 designed according to the invention on both the bottom and rod sides. The ball joint 20 on the bottom side and the ball joint 30 on the rod side are each designed as ring bodies, specifically as turned parts.

[0059] The bottom-side rod end 20 has the bottom-side rod end body 21, and the bottom-side spherical bearing 22 is pressed into its bottom-side receiving bore 23. The bottom-side rod end body 21 has a bottom-side radial annular outer surface 24.

[0060] The bottom closure part 15 has a specially designed bottom closure part section 15.1 for receiving the bottom-side ball joint 20, wherein in Fig. 1 The section plane of the sectional view of the bottom closure part runs lengthwise through the bottom closure part form section 15.1. The - as in Fig. 4 As can be seen more clearly, the web-shaped bottom closure section 15.1 has a bottom-side receiving section 15.3 with a circular, concave radius that follows the radius of the rod head base body 21 on its radial outer surface 24 of the ring body. The receiving section 15.3 forms a bottom-side radial inner surface 15.4, the radius of which coincides with the bottom-side outer surface 24 of the ring body. The portion of the bottom-side outer surface 24 of the ring body that is congruent with the bottom-side radial inner surface 15.4 is the bottom-side radial outer surface 25 of the ring body. These two surfaces 15.4, 25 are fully bonded by means of the bottom-side laser ring segment weld 26 applied on both sides. Through the material-bonded welding in conjunction with the partial form-fit due to the corresponding shape of the two surfaces 15.4, 25 is advantageous from a manufacturing technology perspective, as it allows for reliable pre-positioning before welding and a particularly stable coupling after welding.

[0061] In addition, the bottom-side pressure medium connection bore 15.5 is arranged section by section in the bottom closure part 15.1 of the present embodiment. This bore is advantageously positioned in the bottom closure part 15.1 such that it extends into a transverse plane 15.7 defined by the proximal apex 15.6. Due to the bottom closure part 15.1 tapering distally on both sides from the cylindrical diameter of the bottom closure part 15, sufficient space is provided in the remaining web for the bottom-side pressure medium connection bore 15.5. Therefore, the axial extension between the piston in its bottom-side end position on the bottom closure part 15 and the pivot point of the bottom-side ball joint 20 can be significantly reduced, which offers a decisive advantage by reducing the required installation length of the working cylinder.

[0062] The rod-side joint head 30 serves to link the piston unit 12 to a device to be actuated. Analogous to the bottom-side joint head 20, a rod-side spherical bearing 32 is also integrated into the rod-side joint head 30. This bearing is received in the rod-side receiving bore 33 of the rod-side joint head body 31. To receive the rod-side joint head 30 on the outer end section 12.5 of the piston unit 12, the piston rod has a rod-side receiving section 12.3. With its concave shape, this section forms the opposite section to the rod-side annular outer surface 35, which is a section of the rod-side annular outer surface 34. The rod-side shaped section 12.1 is offset distally to the width of the rod-side spherical bearing 32. The solid cross-sectional end 12.2 is located there.

[0063] Fig. 2 Figure 1 shows a schematic representation of the piston rod of the piston unit 12. At its outer end section 12.5, the piston rod has a rod-side shaped section 12.1, which is designed to receive the rod-side ball joint 30. For this purpose, the rod-side shaped section 12.1 is formed from the cylindrical diameter of the piston rod by a subtractive manufacturing process, in particular by milling. Two recessed areas are created distally and parallel to each other on both sides. This results in a solid cross-sectional end 12.2 of the piston rod. Furthermore, the rod-side receiving section 12.3 is inserted at the rod-side end of the piston rod perpendicular to the main longitudinal axis 17. This section describes a circular segment with the same diameter as the bottom-side ball joint body 21.

[0064] The Fig. 3 Figure 1 shows a schematic exploded view of the piston rod and the rod-side joint head 30. The rod-side joint head 30 is also shown slightly tilted for clarity. The rod-side spherical bearing 32 is located in the rod-side joint head 30. Fig. 3 Not shown for simplicity - included in the rod-side ball joint body 31.

[0065] The piston rod has a rod-side shaped section 12.1 at one end. This is created by milling the area. A shoulder is formed, resulting from the material removal from the solid cross-sectional end 12.2 during the machining process. For the rod-side shaped section 12.1, a prismatic section is first obtained from the cylindrical rod end by means of symmetrical milling on both sides, serving as a preliminary stage for the rod-side shaped section 12.1. To accommodate the rod-side rod end 30, a concave rod-side receiving section 12.3, corresponding to the cylindrical outer shape of the rod-side rod end 30, is subsequently machined in. This section forms a rod-side radial inner surface 12.4 in the axial direction. This surface serves to receive the rod-side rod end 30, whose cylindrical outer shape has a rod-side radial outer surface 34.The contact surface between the rod-side radial outer surface 34 of the annular body and the rod-side radial inner surface 12.4 forms a rod-side radial outer surface 35. All compressive forces of the cylinder are transmitted to a cylinder receptacle via this surface. For a material-fit assembly, a laser ring segment weld 36 is applied axially to the rod-side receptacle bore 33 between the rod-side radial outer surface 35 and the radial inner surface 12.4, thus connecting these surfaces 12.4 and 35. This reliably couples the piston unit 12 and the rod-side rod end 30.

[0066] Fig. 4 Figure 1 shows a schematic representation of the working cylinder, particularly illustrating the positional relationships between the bottom-side ball joint 30 and the bottom closure part 15. The bottom closure part 15 also has an initially cylindrical shape. The bottom closure part section 15.1 is milled out by means of two recesses extending distally to the main longitudinal axis 17 of the cylinder. Its web width corresponds to the axial extent of the bottom-side ball joint body 21. Advantageously, it is also sufficiently wide to allow the bottom-side pressure medium connection bore 15.5 to be located here as well. This results in a significant space saving, as the working cylinder can be made shorter overall. In the exemplary embodiment, the cylinder tube 13 and the bottom closure part 15 are also laser-welded to form the transition to the cylinder.

[0067] Fig. 5Figure 15.1 shows a cross-sectional view of the bottom section of the working cylinder, specifically the bottom closure section 15.1, without the bottom-side ball joint 20. The dashed line indicates the boundary to the remaining bottom closure section 15, which is not visible due to the section plane, and simultaneously the plane of the bottom closure section's top surface 15.2. The bottom closure section 15.1 has the bottom-side receiving section 15.3. The receiving section 15.3 forms the bottom-side radial inner surface 15.4. Reference symbols used

[0068] 11 cylinders 12 Piston unit 12.1 Rod-side forming section 12.2 Solid cross-sectional end 12.3 Rod-side receiving section 12.4 Rod-side radial inner surface 12.5 Outer end section 13 Cylinder tube 14 Guide closure part 15 Bottom closure part 15.1 Bottom closure part forming section 15.2 Bottom closure part cover surface 15.3 Bottom-side receiving section 15.4 Bottom-side radial inner surface 15.5 Bottom-side pressure medium connection bore 15.6 Proximal apex 15.7 Transverse plane 16 Cylinder interior 17 Main longitudinal axis 20 Bottom-side rod end 21 Bottom-side rod end body 22 Bottom-side spherical bearing 23 Bottom-side mounting bore 24 Bottom-side radial outer surface of the ring body 25 Bottom-side radial outer surface of the ring body 26 Bottom-side laser ring segment weld 30 Rod-side rod end 31 Rod-side rod end body body 32 Rod-side spherical bearing 33 Rod-side mounting bore 34 Rod-side radial outer surface of the ring body 35 Rod-side radial outer surface of the ring body 36 Rod-side laser ring segment weld

Claims

1. A working cylinder, comprising a cylinder (11) and a piston unit (12), wherein the cylinder (11) comprises a cylinder tube (13), a guide closure part (14) and a bottom closure part (15), wherein the cylinder tube (13) comprises a first cylinder tube end (13.1) and a second cylinder tube end (13.2), wherein the guide closure part (14) is arranged at the first cylinder tube end (13.1), and the bottom closure part (15) is arranged at the second cylinder tube end (13.2), and wherein the cylinder tube (13) and the closure parts (14, 15) form a cylinder interior (16), wherein the piston unit (12) forms at least one working chamber (16.1) in the cylinder interior (16), slidingly passes through the guide closure part (14) and comprises an outer end portion (12.5), wherein the cylinder (11) comprises a bottom-side joint head (20) that comprises a bottom-side joint head main body (21) and a bottom-side joint bearing (22), wherein the bottom-side joint head main body (21) is designed as an annular body and has a concentric bottom-side receiving bore (23), in which the bottom-side joint bearing (22) is received, and a bottom-side radial annular body outer lateral surface (24), characterized in that the bottom closure part (15) comprises a bottom closure part shaped portion (15.1) which is formed as a monolithic portion of the bottom closure part (15) and rises axially above an outer bottom closure part covering surface (15.2) and has a projection-like basic shape that follows a radius, that the bottom closure part shaped portion (15.1) has a concave indentation which forms a bottom-side receiving portion (15.3) which has a bottom-side radial inner lateral surface (15.4) corresponding to the bottom-side radial annular body outer lateral surface (24), and that at a bottom-side radial annular body outer lateral partial surface (25), the bottom-side joint head main body (21) is welded to the bottom closure part (15) at the bottom-side radial inner lateral surface (15.4) by means of a bottom-side annular-segment-shaped laser weld seam (26).

2. The working cylinder according to claim 1, characterized in that a bottom-side pressure medium connection bore (15.5) is arranged, at least in sections, in the bottom closure part shaped portion (15.1).

3. The working cylinder according to claim 2, characterized in that the bottom-side pressure medium connection bore (15.5) distally exceeds, at least in sections, a transverse plane (15.7), which is spanned by a proximal vertex (15.6) of the bottom-side receiving portion (15.3), to a main longitudinal axis (17).

4. The working cylinder according to one of the previous claims, characterized in that the piston unit (12) comprises a rod-side joint head (30) which comprises a rod-side joint head main body (31) and a rod-side joint bearing (32), that the rod-side joint head main body (31) is formed as an annular body and has a concentric rod-side receiving bore (33), in which the rod-side joint bearing (32) is received, and a rod-side radial annular body outer lateral surface (34), that, at its outer end portion (12.5), the piston unit (12) comprises a rod-side shaped portion (12.1) that is formed as a monolithic portion of the piston unit (12) and rises in an axially distal manner above a full-cross-section end (12.2) and has a projection-like basic shape that follows a radius, that the rod-side shaped portion (12.1) has a concave indentation which forms a rod-side receiving portion (12.3) that has a rod-side radial inner lateral surface (12.4) corresponding to the rod-side radial annular body outer lateral surface (34), and that at a rod-side radial annular body outer lateral partial surface (35), the rod-side joint head main body (31) is welded to the piston unit (12) at the rod-side radial inner lateral surface (12.4) by means of a rod-side annular-segment-shaped laser weld seam (36).

5. The working cylinder according to one of the previous claims, characterized in that the bottom-side joint head main body (21) and the rod-side joint head main body (31) are designed as identically constructed turned parts.

6. The working cylinder according to one of the previous claims, characterized in that the bottom-side annular-segment-shaped laser weld seam (26) or the rod-side annular-segment-shaped laser weld seam (36) are designed as a double-sided weld seam.

7. A working cylinder comprising a cylinder (11) and a piston unit (12), wherein the cylinder (11) comprises a cylinder tube (13), a first closure part and a second closure part, wherein the cylinder tube (13) comprises a first cylinder tube end (13.1) and a second cylinder tube end (13.2), wherein the first closure part is arranged at the first cylinder tube end (13.1) and the second closure part is arranged at the second cylinder tube end (13.2), and wherein the cylinder tube (13) and the closure parts (14, 15) form a cylinder interior (16), wherein the piston unit (12) forms at least one working chamber (16.1) in the cylinder interior (16), slidingly passes through the first closure part and comprises an outer end portion (12.5), wherein the piston unit (12) comprises a rod-side joint head (30) that comprises a rod-side joint head main body (31) and a rod-side joint bearing (32), wherein the rod-side joint head main body (31) is formed as an annular body and has a concentric rod-side receiving bore (33), in which the rod-side joint bearing (32) is received, and a rod-side radial annular body outer lateral surface (34), characterized in that, at its outer end portion (12.5), the piston unit (12) comprises a rod-side shaped portion (12.1) that is formed as a monolithic portion of the piston unit (12) and rises in an axially distal manner above a full-cross-section end (12.2) and has a projection-like basic shape that follows a radius, that the rod-side shaped portion (12.1) has a concave indentation which forms a rod-side receiving portion (12.3) that has a rod-side radial inner lateral surface (12.4) corresponding to the rod-side radial annular body outer lateral surface (34), and that at a rod-side radial annular body outer lateral partial surface (35), the rod-side joint head main body (31) is welded to the piston unit (12) at the rod-side radial inner lateral surface (12.4) by means of a bottom-side annular-segment-shaped laser weld seam (26).

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