Actuating cylinder

Abstract

The present invention relates to an actuating cylinder having a cylinder 11 and a piston unit 12, the cylinder 11 having a bottom joint head 20 having a bottom joint head main body 21 and a bottom joint bearing 22, the bottom joint head main body 21 being in the form of an annular body and having a concentric bottom receiving bore 23 in which the bottom joint bearing 22 is received, and also having a bottom radial annular body outer lateral surface 24, the bottom closure member 15 having a bottom closure member molded part 15.1, the bottom closure member molded part 15.1 being formed as a monolithic part of the bottom closure member 15. and a bottom closure member molding part (15.1) having a concave recess forming a bottom receiving part (15.3) with a bottom radially inner transverse surface (15.4) corresponding to the bottom radially inner transverse surface (24) of the bottom radially inner annular body, and a bottom joint head main body (21) welded at its bottom radially inner transverse surface (15.4) to the bottom closure member (15) by a bottom annular segment-shaped laser welded seam (26) at the bottom radially inner transverse surface (25) of the bottom radially inner annular body.

Description

[Technical Field]

[0001] The present invention relates to an actuation cylinder having a coupling part for articulated coupling with a device to be actuated. [Background technology]

[0002] It is known from the prior art to couple an actuating cylinder to a device to be actuated via a connection module for power transmission, in particular a joint head is disclosed as a connection module of the state of the art.

[0003] The joint head is specially produced as a flame-cut or forged part and houses in the joint eye a joint bearing which can have different degrees of freedom to couple the actuating cylinder without bending stress.

[0004] It is known to use MAG welding to connect the joint head to the bottom closure member, creating a positive material bond. The drawback of this method is that not only the size of the joint head but also its shape is determined by the operating cylinder to be connected, making these measures more expensive. Typically, the joint head is provided with a straight outer profile section that is welded flush onto the sheathed surface of the bottom closure member. To absorb large forces, the MAG weld seam is oversized. The material deposit, which can be up to 15 mm thick and is provided as a weld bead in the throat, disadvantageously requires additional allowance for the distance from the outer profile section to the joint eye to ensure sufficient free space for movement around the so-called joint eye. Because a large amount of heat is generated during welding, temperature-sensitive components, such as joint bearings, can only be attached after welding, or an additional material allowance of at least 30% of the mass must be provided in the joint head to allow the heat to dissipate sufficiently.

[0005] Threaded connections are known in particular from the prior art for connecting a joint head to a piston rod. On the one hand, for this purpose, an external thread must be milled onto the piston rod, and on the other hand, a blind hole with an internal thread must be prepared in the joint head. In addition to the considerable effort required to create the thread pair, a disadvantage is that a required minimum length of the thread must also be observed, and another length allowance may be added to this minimum length for the wrench flats that must also be milled and are intended for torque application or counter-holding when the threaded connection is created. Summary of the Invention [Problem to be solved by the invention]

[0006] The object of the present invention is to provide an actuating cylinder which can be coupled by a joint head, which requires a small installation space, which consumes less material and which can be produced in less time. [Means for solving the problem]

[0007] This problem is solved by the features specified in claim 1 and according to a further aspect of the invention by the features specified in claim 8. Advantageous further developments arise from the subclaims.

[0008] The actuating cylinder according to the invention has as its basic elements a cylinder and a piston and is characterized by a specially designed coupling part with a joint head.

[0009] The cylinder of the actuating cylinder according to the invention comprises, as known per se, a cylinder tube, a first closure member and a second closure member.

[0010] In this design, the cylinder tube has two opposing cylinder tube ends, hereafter referred to as the first cylinder tube end and the second cylinder tube end, and collectively as the cylinder tube ends.

[0011] The first closure member is disposed at the first cylinder tube end, and the second closure member is disposed at the second cylinder tube end. Hereinafter, the first closure member and the second closure member will also be collectively referred to as closure members. The first closure member is designated as a guide closure member, and the second closure member is designated as a bottom closure member.

[0012] The cylinder tube and the closure member arranged thereon form the cylinder interior. For this reason, the two closure members are designed so that they are connected to the respective cylinder tube ends in a pressure-tight manner. To connect the two closure members, they are preferably laser-welded to the cylinder tube along their common circumferential contact surface.

[0013] The piston unit forms at least one working chamber inside the cylinder. The piston unit is preferably designed as an assembly of a piston and a piston rod, the piston rod slidingly passing through a guide closure member. The piston unit can also be designed, for example, as a plunger piston or as a piston unit of a double-rod cylinder. However, the working cylinder according to the invention can also be of other types, in particular, a differential pressure working cylinder or a traction cylinder. Preferably, but not exclusively, it is a hydraulic cylinder.

[0014] The piston unit has an outer end portion, which is to be understood as the distal head portion of the piston unit, 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.

[0015] The actuation cylinder according to the invention also features a specially designed coupling portion.

[0016] A coupling part in the sense of the present invention is a part of the actuating cylinder that is connected to the device to be actuated, for example an excavator arm, through which the forces exerted by the actuating cylinder are transmitted or the forces caused by the actuating device are absorbed. The actuating device itself is not part of the actuating cylinder according to the present invention; it merely represents the functional content of the actuating cylinder according to the present invention. Usually, two opposing coupling parts are arranged on the actuating cylinder, at least one of the coupling parts being designed according to the present invention.

[0017] According to the first independent claim of the present invention, the actuating cylinder has a bottom joint head for this purpose.

[0018] The bottom joint head has a bottom joint head main body and a joint bearing disposed therein, the joint bearing serving to couple the actuation cylinder to the actuating device by means of a coupling bolt in a frictionally optimized and torque-free manner in at least one rotational degree of freedom.

[0019] The bottom joint head main body is designed according to the invention as a ring body, which is understood to be a rotationally symmetrical component that can be advantageously provided with high precision by simple turning operations, in contrast to the cast or forged components known from the prior art. Preferably, the ring body has a substantially hollow cylindrical basic shape.

[0020] The bottom joint head main body has a concentric receiving bore in which the joint bearing is received.

[0021] Additionally, the bottom joint head main body has an outer annular body lateral surface that extends radially and circumferentially on the outer surface of the annular body.

[0022] In accordance with the present invention, the bottom closure member of the actuation cylinder has a specially designed bottom closure member molded portion.

[0023] The bottom closure member molding portion is formed as a monolithic part of the bottom closure member and is provided, in particular, by a milling operation. The bottom closure member molding portion rises axially distally from the outer base closure member covering surface above the plane defined by that surface. The bottom closure member molding portion has a protrusion-like basic shape that follows a radius. The protrusion-like basic shape is considered to be a substantially prismatic body having a base and an upper surface disposed transversely to the bottom closure member covering surface. The basic shape that follows a radius is considered to mean that the bottom closure member molding portion has a concave depression within its substantially prismatic basic shape. In the concave depression, there is a concavely curved surface that geometrically forms a portion of a cylindrical lateral surface, hereinafter referred to as the bottom radially inner lateral surface.

[0024] The concave recess forms a receiving portion. The receiving portion is molded to have a radially inner lateral surface that corresponds to the radially outer lateral surface of the annular body. As an advantage, the shape of the lateral cylindrical surface portion of the receiving portion allows for flat reception of the joint head main body. The portion of the radially outer annular body lateral surface that presses and rests flat against the radially inner lateral surface of the concave receiving portion of the bottom closure member molding portion is also referred to hereinafter as the annular body outer lateral partial surface.

[0025] This surface contact advantageously allows for high power transmission of compressive forces, especially when they occur when the actuating cylinder is in its extended operating state, while at the same time the corresponding surfaces provide a positive partial fit between the joint head main body and the bottom closure member, thereby resisting twisting and tilting of the joint head main body.

[0026] The bottom joint head main body is welded at its radially inner lateral surface to the bottom closure member by a bottom annular segment-shaped laser weld seam at the radially inner lateral surface of the radially outer lateral surface of the annular body. The full-surface weld on the corresponding surfaces of the joint head main body and the bottom closure member creates a secure, material-positive connection between the two parts, allowing the transmission of high tensile forces, especially those that occur when the actuating cylinder is in a retracted operating state.

[0027] The solution according to the invention for providing an actuating cylinder that can be articulated has the following advantages in particular:

[0028] Surprisingly, the combination of the flush fit of the corresponding cylindrical transverse part surfaces and the precise laser annular segment-shaped weld seam creates a solution that overcomes in a simple manner the drawbacks known from prior art solutions for producing joint heads: no elaborate thread milling is required, and the drawbacks of MAG welding, with its inaccurate and intense heat associated with high material deposition, are also absent.

[0029] Furthermore, the bottom closure element can be provided as a turned part in a particularly simple and cost-effective manner. Due to its simple shape, the bottom closure element molded part can also be produced using conventional milling machines in the same technological process as the bottom closure element, without the need for an additional processing station. This results in major advantages in terms of manufacturing effort and associated production costs. The low energy input per length of the laser weld allows for a small heat-affected zone, thereby avoiding thermal damage or deformation of the bottom closure element or the joint head main body. In particular, laser welding according to the present invention is also possible with pre-installed sensitive components, such as polymer seals.

[0030] In addition, the drawbacks of the current state of the art, such as those present with MAG welding, can be overcome by laser welding the joint head main body to the bottom closure member, even when the joint bearing is already installed. This allows the joint head to be manufactured as a complete assembly of the joint head main body and joint bearing in mass production with high precision prior to welding. This has the advantage of achieving higher precision and tighter tolerances.

[0031] In an advantageous further development, the actuating cylinder is characterized in that the pressure medium connection bore on the bottom side is at least partly arranged in the bottom closure member molded part.

[0032] According to this further development, the insulation space provided by the bottom closure member molded part is advantageously simultaneously used for arranging the pressure medium connection bore, so that the overall length of the actuating cylinder can be reduced for the same stroke length by using the axially distal protrusion of the bottom closure member molded part.

[0033] The advantage of this is that functional integration is created by the bottom closure member molding part, which firstly receives the joint head in the force transmission system and secondly creates an installation space axially distal to the bottom closure covering surface to receive the pressure medium connection bore.

[0034] In a particular variant based on this design, the actuating cylinder is characterized in that the bottom pressure medium connection bore extends at least partially distally beyond a transverse plane relative to the longitudinal axis, which is spanned by the apex line of the receiving part.

[0035] The apex line of the receiving portion is the point at which the bottom closure member molded portion has the slightest rise above the bottom closure member covering surface and at which, in the assembled state, the joint head main body extends the furthest in the proximal direction.

[0036] The pressure medium connection can therefore be positioned in the area of ​​the bottom closure element with the greatest material overlap, and at the same time very far distally. This design results in the greatest bending stiffness of the connection. Therefore, particularly large reductions in overall length are advantageously possible without affecting the stroke length.

[0037] According to a further advantageous development, the actuating cylinder is characterized in that it has a rod-side joint head, which forms a rod-side articulated connection between the actuating cylinder and the device to be actuated.

[0038] The rod-side joint head also has a joint head main body, hereinafter referred to as rod-side joint body, and a joint bearing, hereinafter referred to as rod-side joint bearing. Therefore, unless special features arise from the following description sections, the description of the bottom-side joint head and its arrangement in the working cylinder also applies accordingly to the rod-side joint head.

[0039] The rod-side joint head main body is also designed as an annular body. It has a concentric receiving bore on the rod side. The rod-side joint bearing is correspondingly received therein. Like the bottom-side joint head main body, the rod-side joint main body also has a substantially hollow cylindrical basic shape. The joint head also has a radial annular body outer transverse surface on the rod side.

[0040] The piston unit has a rod-side moulding at its outer end.

[0041] The rod-side molded portion corresponds to the bottom closure member molded portion, taking into account special rod-side features. The rod-side molded portion is machined, preferably by milling, from the cylindrical basic shape of the outer end portion of the piston unit. It is then formed as a monolithic part of the piston unit. Thus, the rod-side molded portion has a protrusion-like basic shape that rises above the cylindrical portion of the piston unit in the axially distal direction and follows a radius. The rod-side molded portion has a concave recess that forms the rod-side receiving portion. Furthermore, the rod-side receiving portion has a radially inner lateral surface that corresponds to the radially outer lateral surface of the annular body.

[0042] The rod-side molded portion is in exact conformance with the outer lateral surface of the joint head main body in diameter, and preferably also in width, and is preferably limited in length by the outer diameter of the piston rod.

[0043] With regard to the form-fit connection between the rod-side molded part and the rod-side joint head main body, the rod-side joint head main body is welded at its rod-side radially inner lateral surface to the piston unit by means of a rod-side annular segment-shaped laser weld seam at the rod-side radially annular body outer lateral partial surface of the rod-side radially annular body outer lateral surface.

[0044] According to a particularly advantageous further development, the actuating cylinder with rod-side and bottom-side joint head is characterized in that the bottom-side joint head main body and the rod-side joint head main body are designed as identically constructed components.

[0045] This is advantageous for the production of the joint head. In addition, there are significant advantages for the production logistics of actuating cylinders, since different joint heads on the bottom and rod sides do not have to be taken into account. Due to the low thermal stresses caused by the laser-welded seams in the shape of annular segments, it is even possible to manufacture the joint as a complete assembly consisting of the main body and joint bearing in large quantities with high quality.

[0046] Furthermore, the present invention provides the advantage that the joint heads can be manufactured in graduated sizes without having specific manufacturing specifications, so that for adjustment, only the bottom closure member molding part or the rod side molding part needs to be milled according to the respective size of the joint heads available in large quantities.

[0047] According to a further advantageous development, the actuating cylinder is characterized in that the annular segment-shaped laser welded seam on the bottom side or the annular segment-shaped laser welded seam on the rod side is formed as a double-sided welded seam.

[0048] Stability is advantageously increased with this design while thermal stresses are reduced because the energy per length input into the line is distributed over time.

[0049] Another aspect of the invention relates to an actuating cylinder according to the independent subclaim, which has only a rod-side joint head according to the invention.

[0050] The basic structure of the actuating cylinder with respect to the cylinder, cylinder tube, closure member and piston unit corresponds to the actuating cylinder according to the main claim, whereby the recitations in that claim also apply in a corresponding manner to the actuating cylinder according to the independent subsidiary claim described therein. Furthermore, the recitations in the main claim regarding the formation of the rod-side molded part at the outer end portion of the rod-side joint head and piston unit apply in a corresponding manner to the further rod-side joint head.

[0051] The invention is explained in more detail by way of exemplary embodiments with the aid of the following figures. [Brief explanation of the drawings]

[0052] [Figure 1] FIG. 2 is a schematic cross-sectional view of an actuating cylinder. [Figure 2] Schematic lateral view of the piston rod. [Figure 3] 1 is a schematic view of a rod-side molded portion of a piston having an annular body. FIG. [Figure 4] FIG. 2 is a schematic transverse view of the actuation cylinder. [Figure 5] FIG. 2 is a schematic cross-sectional view of the bottom portion of the actuation cylinder. DETAILED DESCRIPTION OF THE INVENTION

[0053] In this context, the same reference numbers in the various figures always refer to the same features or components. Reference numbers are also used in this description even if they are not shown in the figure in question.

[0054] FIG. 1 is a schematic cross-sectional view of an exemplary embodiment of an actuation cylinder.

[0055] Its basic components are a cylinder 11 and a piston unit 12. A cylinder tube 13 is closed by a guide closure member 14 and a bottom closure member 15, thus forming a cylinder interior 16.

[0056] In this exemplary embodiment, the actuating cylinder has joint heads 20, 30 designed according to the invention on both the bottom and rod sides. The bottom joint head 20 and the rod joint head 30 are each designed as an annular body, in particular as a turned part.

[0057] The bottom joint head 20 has a bottom joint head main body 21 and a bottom joint bearing 22 pressed into a bottom receiving bore 23. The bottom joint head main body 21 has a bottom radially annular body outer lateral surface 24.

[0058] The bottom closure member 15 has a bottom closure member molding portion 15.1 specially designed to receive the bottom joint head 20; the cross-sectional plane of the bottom closure member cross-section extends longitudinally through the bottom closure member molding portion 15.1 in FIG. 1 . The bottom closure member molding portion 15.1, which has a protrusion-like configuration better seen in FIG. 4 , has a circular concave bottom receiving portion 15.3 that follows the radius of the joint head main body 21 at its radially annular outer lateral surface 24. The bottom receiving portion 15.3 forms a bottom radially inner lateral surface 15.4, the radius of which coincides with the bottom radially inner lateral surface 24. The portion of the bottom radially outer lateral surface 24 that coincides with the bottom radially inner lateral surface 15.4 is the bottom radially outer lateral partial surface 25. These two surfaces 15.4, 25 are completely connected over the entire surface in a positive material manner by means of a laser welded seam 26 in the form of a bottom annular segment applied on both sides. From a manufacturing point of view, the positive material welded connection, together with the partial form fit due to the corresponding shapes of the two surfaces 15.4, 25, allows both reliable pre-positioning before welding and a particularly stable connection after welding.

[0059] Additionally, the bottom pressure medium connection bore 15.5 is partially arranged in the bottom closure member molding 15.1 in this exemplary embodiment. It is advantageously accommodated in the bottom closure member molding 15.1 so as to extend into the transverse plane 15.7 traversed by the proximal apex 15.6. Because the bottom closure member molding 15.1 narrows distally on both sides relative to the cylindrical diameter of the bottom closure member 15, there is sufficient space in the remaining projection for the bottom pressure medium connection bore 15.5. Therefore, the axial extension between the piston in the bottom end position of the bottom closure member 15 and the articulation point of the bottom joint head 20 can be significantly reduced, which is a decisive advantage due to the reduction in the required structural length of the actuating cylinder.

[0060] The rod-side joint head 30 is used to connect the piston unit 12 to the device to be operated. Similar to the bottom-side joint head 20, the rod-side joint bearing 32 is also integrated into the rod-side joint head 30. It is received in the rod-side receiving bore 33 of the rod-side joint head main body 31. To receive the rod-side joint head 30 in the outer end portion 12.5 of the piston unit 12, the piston rod has a rod-side receiving portion 12.3. With its concave shape, this forms a counter portion for the rod-side annular body outer lateral partial surface 35, which is part of the rod-side annular body outer lateral surface 34. The rod-side molded portion 12.1 is set distally across the width of the rod-side joint bearing 32. The full-section end 12.2 is located there.

[0061] FIG. 2 shows a schematic diagram of the piston rod of the piston unit 12. At its outer end portion 12.5, it has a rod-side molded section 12.1 designed to receive the rod-side joint head 30. To this end, the rod-side molded section 12.1 is formed by a material-removal manufacturing process, in particular by milling, based on the cylindrical diameter of the piston rod. For this purpose, two recessed areas are created on both sides, distally and parallel to each other, which connect to the full-section end 12.2 of the piston rod. Furthermore, a rod-side receiving section 12.3 is introduced into the rod-side end of the piston rod perpendicular to the main longitudinal axis 17. This describes a circular sector with the same diameter as the bottom joint head main body 21.

[0062] Figure 3 shows a schematic exploded view of the piston rod and rod-side joint head 30. The rod-side joint head 30 is also shown slightly tilted for better representation. In the rod-side joint head 30, a rod-side joint bearing 32, which is not shown in Figure 3 for simplicity, is received in the rod-side joint head main body 31.

[0063] The piston rod has a rod-side profile 12.1 at one end, which is achieved by milling this area. This leads to a shoulder resulting from the full-section end 12.2, which is formed by removing material during machining. For the rod-side profile 12.1, a prismatic section, which serves as a preliminary stage for the rod-side profile 12.1, is first obtained from the cylindrical rod end by symmetrical milling on both sides. To accommodate the rod-side joint head 30, a concave rod-side receiving section 12.3 is then created, corresponding to the cylindrical outer shape of the rod-side joint head 30. This forms the rod-side radial inner transverse surface 12.4 in the axial direction. This surface serves to receive the rod-side joint head 30, which in turn has a rod-side radial annular outer body transverse surface 34. The contact between the rod-side radially outer lateral surface 34 of the annular body and the rod-side radially inner lateral surface 12.4 forms the rod-side radially outer lateral partial surface 35. All compressive forces of the cylinder are transmitted to the cylinder receiving unit via this surface. For positive assembly, an annular segment-shaped laser welded seam 36 is generated between the rod-side radially outer lateral partial surface 35 of the annular body and the rod-side radially inner lateral surface 12.4 axially relative to the rod-side receiving bore 33, thereby connecting these surfaces 12.4, 35. Thus, the piston unit 12 and the rod-side joint head 30 are securely joined.

[0064] FIG. 4 shows a schematic diagram of the actuation cylinder, particularly the positional relationship between the bottom joint head 20 and the bottom closure element 15. Here, the bottom closure element 15 also has an original cylindrical shape. The bottom closure element molded part 15.1 is milled with two recesses extending distally to the cylinder's main longitudinal axis 17. The width of this protrusion corresponds to the axial extension of the bottom joint head main body 21. It is therefore also advantageously wide enough that the bottom pressure medium connection bore 15.5 can also be located there. As a result, the actuation cylinder can be made shorter overall, which offers a decisive advantage in terms of the required construction space. As a transition to the cylinder, the cylinder tube 13 and the bottom closure element 15 are also laser-welded in the illustrated exemplary embodiment.

[0065] 5 additionally shows the bottom closure molding part 15.1, again without the bottom joint head 20, in a cross-section of the bottom part of the actuating cylinder, the dotted line indicating the interface with the rest of the bottom closure part 15, which is not visible due to the cross-sectional plane, and at the same time the plane of the bottom closure part covering surface 15.2. The bottom closure molding part 15.1 has a bottom receiving part 15.3, which forms the bottom radially inner lateral surface 15.4. [Explanation of symbols]

[0066] 11 cylinders 12 Piston unit 12.1 Rod side molding part 12.2 Full section end 12.3 Rod side receiving part 12.4 Radially inner lateral surface of rod side 12.5 Outer end section 13 Cylinder tube 13.1 First Cylinder Tube End 13.2 Second Cylinder Tube End 14 Guide closure member 15 Bottom closure member 15.1 Bottom Closure Molding 15.2 Bottom closure member coated surface 15.3 Bottom Receptacle 15.4 Bottom radially inner lateral surface 15.5 Bottom pressure medium connection bore 15.6 Proximal Apex 15.7 Transverse plane 16 Inside the cylinder 17 Main longitudinal axis 20 Bottom Joint Head 21 Bottom joint head main body 22 Bottom joint bearing 23 Bottom receiving bore 24 bottom radial annular body outer lateral surface 25 bottom radial annular body outer lateral partial surface 26 Laser welded seam in the shape of an annular segment on the bottom side 30 Rod side joint head 31 Rod side joint head main body 32 Rod side joint bearing 33 Rod side receiving bore 34 Rod-side radial annular body outer lateral surface 35 Rod-side radial annular body outer lateral partial surface 36 Laser welded seam in the shape of an annular segment on the rod side

Claims

1. An operating cylinder having a cylinder (11) and a piston unit (12), The cylinder (11) includes a cylinder tube (13), a guide closure member (14), and a bottom closure member (15). The cylinder tube (13) has a first cylinder tube end (13.1) and a second cylinder tube end (13.2), the guide closure member (14) is located at the first cylinder tube end (13.1), and the bottom closure member (15) is located at the second cylinder tube end (13.2). The cylinder tube (13) and the closure members (14, 15) form the inside of the cylinder (16), and In an operating cylinder, the piston unit (12) forms at least one operating chamber (16.1) inside the cylinder interior (16), slides through the guide closure member (14), and has an outer end portion (12.5), The cylinder (11) has a bottom joint head (20) which has a bottom joint head main body (21) and a bottom joint bearing (22), The bottom joint head main body (21) is designed as an annular body and has a concentric bottom receiving bore (23) into which the bottom joint bearing (22) is received, and a bottom radial annular body outer lateral surface (24). The bottom closure member (15) has a bottom closure member molded portion (15.1), which is formed as a monolithic portion of the bottom closure member (15) and has a basic protruding shape that rises axially above the outer bottom closure member covering surface (15.2) and follows a radius. The bottom closure member molded portion (15.1) has a concave recess that forms a bottom receiving portion (15.3) having a bottom radially inner lateral surface (15.4) corresponding to the bottom radially annular body outer lateral surface (24), and An operating cylinder characterized in that the bottom joint head main body (21) is welded to the bottom closure member (15) at the bottom radial inner lateral surface (15.4) by a laser welded seam (26) in the shape of a bottom annular segment on the outer lateral surface (25) of the bottom radial annular body.

2. The operating cylinder according to claim 1, characterized in that the bottom pressure medium connection bore (15.5) is positioned in the bottom closure member molded portion (15.1) in at least some cross-sections.

3. The operating cylinder according to claim 2, characterized in that the bottom pressure medium connecting bore (15.5) extends distally with respect to the main longitudinal axis (17) in at least several cross-sections across the transverse plane (15.7) traversed by the proximal apex (15.6) of the bottom receiving portion (15.3).

4. The piston unit (12) has a rod-side joint head (30) which has a rod-side joint head main body (31) and a rod-side joint bearing (32), The main body (31) of the rod-side joint head is formed as an annular body and has a concentric rod-side receiving bore (33) into which the rod-side joint bearing (32) is received, and a rod-side radial annular body outer lateral surface (34). The piston unit (12) has a rod-side molded portion (12.1) at its outer end portion (12.5), and the rod-side molded portion is formed as the monolithic portion of the piston unit (12), and has a basic protruding shape that rises above the entire cross-sectional end portion (12.2) in an axial distal manner and follows a radius. The rod-side molded portion (12.1) has a concave recess that forms a rod-side receiving portion (12.3) having a rod-side radially inner lateral surface (12.4) corresponding to the rod-side radially annular body outer lateral surface (34), and The operating cylinder according to claim 1, characterized in that 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 a laser-welded seam (36) in the shape of a rod-side annular segment on the outer lateral partial surface (35) of the rod-side radial annular body.

5. The operating cylinder according to claim 4, characterized in that the bottom joint head main body (21) and the rod-side joint head main body (31) are designed as identically constructed turning members.

6. The operating cylinder according to claim 1 or 4, characterized in that the bottom annular segment-shaped laser-welded seam (26) or the rod-side annular segment-shaped laser-welded seam (36) is designed as a double-sided welded seam.

7. An operating cylinder having a cylinder (11) and a piston unit (12), The cylinder (11) comprises a cylinder tube (13), a first closure member, and a second closure member. The cylinder tube (13) has a first cylinder tube end (13.1) and a second cylinder tube end (13.2), the first closure member is located at the first cylinder tube end (13.1), and the second closure member is located at the second cylinder tube end (13.2). The cylinder tube (13) and the closure members (14, 15) form the inside of the cylinder (16), and In an operating cylinder, the piston unit (12) has at least one operating chamber (16.1) inside the cylinder (16), passes through the first closure member in a sliding manner, and has an outer end portion (12.5), The piston unit (12) has a rod-side joint head (30) which includes a rod-side joint head main body (31) and a rod-side joint bearing (32). The main body (31) of the rod-side joint head is designed as an annular body and has a concentric rod-side receiving bore (33) into which the rod-side joint bearing (32) is received, and a rod-side radial annular body outer lateral surface (34), The piston unit (12) has a rod-side molded portion (12.1) at the outer end portion (12.5), and the rod-side molded portion is formed as the monolithic portion of the piston unit (12), and has a basic protruding shape that rises axially distally above the entire cross-sectional end portion (12.2) and follows a radius. The rod-side molded portion (12.1) has a concave recess that forms a rod-side receiving portion (12.3) having a rod-side radially inner lateral surface (12.4) corresponding to the rod-side radially annular body outer lateral surface (34), and An operating cylinder characterized in that the main body of the rod-side joint head (31) is welded to the piston unit (12) at the inner lateral surface (12.4) of the rod-side radial annular body by a laser-welded seam (26) having a bottom annular segment shape at the outer lateral partial surface (35) of the rod-side radial annular body.

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