Working Cylinder

Abstract

The present invention relates to an actuating cylinder comprising a cylinder 1 and a piston unit 2, the cylinder 1 having a cylinder tube 3, a first closure part 4a and a second closure part 4b, the cylinder tube 3 having a first cylinder tube end 5a and a second cylinder tube end 5b, the first closure part 4a being arranged at the first cylinder tube end 5a and the second closure part 4b being arranged at the second cylinder tube end 5b, the cylinder tube 3 and the closure parts 4a, 4b forming a cylinder interior 6, the piston unit 2 forming at least one actuating chamber 6.1 in the cylinder interior 6. The actuating cylinder has a rod-side threaded connection module 7, which is formed of a closure part 4a and slidably passes through the closure part 4a and has an outer end section 2.1, the actuating cylinder is designed to be corrosion-resistant and has a threaded section 7.1 and a welded section 7.2, the threaded section 7.1 is designed to be connected to an actuating device, the rod-side threaded connection module 7 is welded by its welded section 7.2 to the outer end section of the piston unit 2 by a weld 7.4, and the threaded section is arranged on the longitudinal axis 7.3 of the piston unit 2.

Description

[Technical field]

[0001] The present invention relates to an actuation cylinder having a connection section for threaded connection to a device to be actuated. [Background technology]

[0002] Conventionally, it is known to couple an actuating cylinder to an actuated device by screwing the actuating cylinder to the actuated device by means of a fastening thread, which can be done directly or indirectly via a connection module such as a ball joint or a fork eye.

[0003] Such fastening threads are created by machining both the piston rod and the bottom closure part. A disadvantage of machining the fastening threads in the piston rod is that, for example, the expensive pre-applied chrome plating is removed, resulting in a loss of corrosion protection. Another disadvantage is that the spanner flats intended for torque application or locking during screwing require a high level of material removal, causing an undesirable embrittlement of the cross section.

[0004] Subsequent coating to provide corrosion protection is either not possible or very difficult to achieve.

[0005] Disadvantageously, unprotected fastening threads are subject to high levels of corrosion and begin to rust very quickly. As a countermeasure, it is known to apply a thick layer of grease to reduce the effects of corrosion, especially during sea transport. Such a layer of grease needs to be cleaned off after assembly. In addition to the insufficient corrosion protection effect, the environmental impact and the large amount of labor involved are also disadvantageous. Summary of the Invention [Problem to be solved by the invention]

[0006] The object of the invention is to provide a screwable actuating cylinder which is reliably protected against corrosion and which can be produced with reduced material and time expenditure. [Means for solving the problem]

[0007] This problem is solved by the features defined in claim 1 and according to a further aspect of the invention by the features defined in claim 2. Preferred further embodiments are given by the dependent claims.

[0008] The working cylinder according to the invention comprises as its basic elements a cylinder and a piston unit and is characterised by a special threaded connecting module.

[0009] The cylinder of the working cylinder according to the invention comprises, in a manner known per se, a cylinder tube, a first closure part and a second closure part.

[0010] The cylinder tube has two opposing cylinder tube ends, which will be referred to hereinafter as a first cylinder tube end and a second cylinder tube end, and collectively referred to as cylinder tube ends.

[0011] The first closure part is arranged at the first cylinder tube end, and the second closure part is arranged at the second cylinder tube end. In the following, the first closure part and the second closure part are also collectively referred to as closure parts. The cylinder tube and the closure parts arranged thereon form the cylinder interior. For this purpose, the two closure parts are designed to be connected in a gas-tight manner to the respective corresponding cylinder tube end. These connections are preferably made by laser welding the cylinder tube and the two closure parts along their common circumferential contact surface.

[0012] The piston unit forms at least one working chamber inside the cylinder. The piston unit is preferably designed as an assembly consisting of a piston and a piston rod, the piston rod slidingly passing through at least one of the closure parts, which is a guide closure part. However, the piston unit may also be provided, for example, as a plunger piston or as a piston unit of a double-rod cylinder. The working cylinder according to the invention may also be of other types, in particular a differential working cylinder or a pull cylinder. Preferably, the working cylinder is a hydraulic cylinder, but is not limited to this type.

[0013] The piston unit has an outer end section, which is understood to be the distal end head section of the piston unit, preferably the piston rod, located outside the cylinder interior. In the case of a plunger-cylinder, the outer end section is the distal end head of the plunger piston.

[0014] The working cylinder according to the invention is also characterized by a specially designed coupling section.

[0015] For the purposes of the present invention, a coupling section is understood to be a part of the working cylinder that is connected to the device to be actuated, for example the arm of an excavator, through which the forces exerted by the working cylinder are transmitted or through which the forces emanating from the device to be actuated are absorbed. The device to be actuated is not itself a part of the working cylinder according to the invention, but merely represents the functional background of the working cylinder according to the invention. Usually, two opposing coupling sections are arranged on the working cylinder, at least one of the coupling sections being designed according to the invention.

[0016] For this reason, the actuating cylinder according to the invention has a threaded coupling module on the rod side.

[0017] The rod-side threaded connection module is corrosion-resistant according to the invention and is preferably a galvanized or stainless steel part, in particular a V2A or V4A part.

[0018] According to the invention, the threaded connection module has a threaded section and a welded section. Preferably, the rod-side threaded connection module is designed in the form of a screw, the threaded shank forming the threaded section and the screw head forming the welded section. In the following, the thread of the threaded section is also called the fastening thread or the connecting thread.

[0019] The threaded section is designed and intended to be coupled to the device to be actuated, and is adapted to screw into a mating thread of said device, with metric threads being preferred.

[0020] The weld section runs longitudinally following the threaded section and, according to the invention, is welded to the outer end section of the piston unit by means of a weld seam. Preferably, the welded partner of the weld section is the outer head section of the piston rod. However, in the sense of the invention, the designation as rod-side threaded coupling module is also used when the outer end section does not refer to a piston rod in the narrow sense, but for example to a plunger piston of a plunger cylinder.

[0021] The weld is preferably formed as a circumferential laser weld, so that a welded joint can be advantageously created that connects the corrosion-resistant surface coating of the piston rod to the rod-side threaded coupling module that is designed to be corrosion-resistant, so that an uninterrupted corrosion-resistant surface can be provided.

[0022] According to the invention, the double rod cylinder preferably has two rod-side threaded coupling modules, each of which is welded to one of the two outer end sections of the piston rod by means of welds.

[0023] According to another aspect of the invention, the actuating cylinder according to the other independent claim is characterized by a threaded coupling module on the base side.

[0024] The basic structure of an actuating cylinder having a base side threaded connection module corresponds to the basic structure of an actuating cylinder having a rod side threaded connection module, and therefore the contents of the description regarding the rod side apply accordingly, except where the following specific features apply.

[0025] The first closure part of the cylinder of the actuating cylinder with the base threaded coupling module is designed exclusively as a guide closure part, the second closure part is a base closure part.

[0026] Here, the distinctive feature is the proximal threaded coupling module.

[0027] The proximal threaded connection module is primarily designed similarly to the rod-side threaded connection module, and therefore the description of the rod-side threaded connection module also applies accordingly to the proximal threaded connection module, taking into account special features.

[0028] The base end threaded connection module and the rod end threaded connection module are also each referred to as a threaded connection module, and collectively referred to as threaded connection modules.

[0029] The base threaded connection module is also corrosion resistant and includes a threaded section and a weld section. In the case of the base threaded connection module, the weld section is welded to the outer axial surface of the base closure part by a weld. The outer axial surface is the base outward facing cladding surface of the base closure part. Typically, this is the circular surface of a cylindrical base closure part.

[0030] In addition, the threaded section of the threaded connection module is arranged on the longitudinal axis of the actuating cylinder, in particular, the threaded section of the rod side threaded connection module is arranged on the longitudinal axis of the piston unit and the threaded section of the base side threaded connection module is arranged on the longitudinal axis of the cylinder.

[0031] Thus, an actuation cylinder may have one or two rod-side threaded connection modules, one base-side threaded connection module, or one rod-side threaded connection module and one base-side threaded connection module.

[0032] The solution according to the invention, both in terms of the design of the threaded connection module as a rod-side threaded connection module and in terms of the design of the threaded connection module as a base-side threaded connection module, has in particular the following advantages:

[0033] Surprisingly, a very simple and at the same time particularly effective solution has been found for providing reliable corrosion protection to fastening threads. In contrast to the prior art, the corrosion protection according to the invention is achieved without the use of additional measures and without adverse environmental effects.

[0034] The production of the actuation cylinder according to the invention is also particularly cost-effective and time-saving: instead of the time-consuming machining of the fastening threads, only laser welding of a maximum of around 2 seconds is required.

[0035] Another advantage results from the material savings achieved, especially in the case of rod-side threaded connection modules, as the length of the piston rod, which is costly, can be reduced by eliminating the need for a section for the fastening thread, which is produced directly on the piston rod by machining, which is advantageously replaced by welding of the threaded connection module.

[0036] A further advantage is the high material quality and thus the high resistance to mechanical loads of the welded threaded connection module according to the invention, especially when designed as a standardized screw.

[0037] According to a further advantageous refinement, the rod-side or base-side threaded connection module is designed as a cap screw.

[0038] The head of the socket head bolt forms the weld section and the threaded shank of the socket head bolt forms the threaded section.

[0039] Advantageously, the head of the socket head bolt provides a weld section with a large surface compared to the cross section of the threaded section. Furthermore, according to this further refinement, the threaded connection module can advantageously be provided by inexpensive components that are directly available on the market. In particular, it is advantageous that a high degree of standardization and quality assurance, expressed for example in strength classes, is available and can be exploited. Preferably, screws of strength class 8.8 are used, which are in addition very suitable for forming welds as laser welds.

[0040] According to a further advantageous embodiment, the rod-side threaded connection module is designed as a hexagon head screw.

[0041] In addition to the advantages of the socket head bolts mentioned above, the hexagonal bolts are particularly advantageous in that the hexagonal head is still laterally accessible as a screw drive after the connection to the outer end section of the piston unit has been made by means of a weld, and therefore advantageously the spanner flat is directly available as a drive for screwing the rod-side threaded coupling module to the device to be actuated, without the need for any further additional means.

[0042] According to another further advantageous refinement, the actuating cylinder according to the invention is characterized in that the base-side threaded connection module is designed as a cylinder head screw and the welded section is designed as a cylindrical screw head, the second closure part provided as the base closure part has a cylindrical bore hole on its outer axial surface, the cylindrical screw head is radially received by the cylindrical bore hole in a form-fitting manner, and the weld is designed as an axial ring weld.

[0043] According to this further advantageous refinement, a bore hole in the form of a blind hole can be cut into the outer axial surface by machining during the manufacture of the base closure part. The inner diameter of this bore hole is adapted to the outer diameter of the cylindrical screw head, preferably with a precise fit or interference fit. The base threaded coupling module, here designed as a cylinder head screw, is then axially fixed in the direction of its distal end, except for the linear degree of freedom, with the screw head being axially inserted into the bore hole. An axially oriented laser ring weld is then created, preferably by laser welding, which results in a reliable physical connection between the threaded coupling module and the base closure part.

[0044] This further refinement simplifies manufacturing in a particularly advantageous manner, since the threaded coupling module and the base closure part are precisely aligned with one another before welding and are fixed by an interference fit.

[0045] According to another further refinement, the actuating cylinder is characterized in that the rod-side threaded coupling module or the base-side threaded coupling module is designed as a galvanized screw or a stainless steel screw.

[0046] Zinc-plated and stainless steel screws have a high corrosion resistance and offer a high quality of processing reliability at low cost. Stainless steel screws are considered to be screws made of stainless steel, for example of material number 4301. Advantageously, therefore, a continuous corrosion-resistant surface is provided, especially when the weld is made as a laser weld.

[0047] According to another further advantageous refinement, the threaded connection module has a protective coating layer.

[0048] In addition to the use of corrosion-resistant screws or threaded pins as welding nozzles, this further refinement also provides for other threaded coupling modules covered with a protective layer, which are connected to the base closure part or the piston unit by laser welding. Such a protective coating layer can be, for example, a chromium or nickel layer.

[0049] Exemplary embodiments of the invention will now be explained in more detail with reference to the accompanying drawings, in which: FIG. [Brief description of the drawings]

[0050] [Figure 1] FIG. 1 is a cross-sectional view of an actuation cylinder having a threaded coupling module as a socket bolt. [Diagram 2] FIG. 2 is a cross-sectional view of an actuation cylinder having a threaded coupling module as a stud bolt. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0051] In the various figures, like features or components are numbered likewise, and the description may use numbers that are not shown in the associated figures.

[0052] FIG. 1 shows an actuating cylinder in an exemplary embodiment in which the threaded coupling modules 7, 8 are designed as socket bolts.

[0053] The basic structure of the actuating cylinder comprises a cylinder 1 and a piston unit 2.

[0054] The cylinder 1 has a cylinder tube 3 having a first cylinder tube end 5a and a second cylinder tube end 5b. A first closure part 4a, here a guide closure part, provided at the first cylinder tube end 5a, and a second closure part 4b, here a base closure part, provided at the second cylinder tube end, are sealably arranged by laser welds such that the closure parts 4a, 4b and the cylinder tube 3 surround the cylinder interior 6.

[0055] In the exemplary embodiment, the piston unit 2 is designed in two parts, with a piston and a piston rod (each without a reference number) connected to each other. The piston unit 2 passes through the first closure part 4a together with the piston rod and at the same time forms at least one working chamber 6.1 in the cylinder interior 6. In the exemplary embodiment, reference number 6.1 denotes a piston chamber. A piston rod chamber is provided in the exemplary embodiment as a further working chamber (without a reference number).

[0056] The rod-side threaded connection module 7 is arranged on the outer end section 2.1 of the piston unit 2, here on the front end of the piston rod. The rod-side threaded connection module 7 is designed as a hexagonal bolt, in such a way that its threaded section 7.1 is formed by the shank of the screw and its welded section 7.2 is formed by the hexagonal head. The welded section 7.2 therefore has an axial front face facing the axial front face of the outer end section 2.1. Both front faces are fully welded by the weld 7.4 as a laser weld, which is radially arranged. The radial arrangement is highlighted by dashed lines. After welding, the spanner flats of the hexagonal head can advantageously be used for assembly by screwing the threaded section 7.1 to the device to be actuated. For optimal force transmission, the longitudinal axis of the threaded section 7.1 lies on the longitudinal axis 7.3 of the piston unit 2.

[0057] Furthermore, the base-side threaded coupling module 8, designed as a cylinder head screw, is arranged on the outer axial surface 4b.1 of the second closure part 4b. The second closure part 4b has a bore hole on the outer axial surface 4b.1, the inner diameter of which corresponds to the outer diameter of the cylindrical head of the cylinder head screw and matingly receives the head of the cylinder head screw. The head of the cylinder head screw thus forms the weld section 8.2 and its threaded shank forms the threaded section 8.1. Here, the weld is also designed as a laser weld, the weld 8.4 being introduced axially (see dashed line emphasis). The weld 8.4 is thus present as a cylindrical jacket surface at the contact surface of the bore hole and the weld section 8.2, which is formed by the screw head. Here too, the longitudinal axis of the threaded section 8.1 lies on the longitudinal axis 8.3 of the cylinder 1 for optimal force transmission.

[0058] FIG. 2 shows a further exemplary embodiment, the basic structure of which corresponds to that of the exemplary embodiment shown in FIG.

[0059] According to FIG. 2, however, the threaded connection modules 7, 8 are designed as stud bolts with conical ends, forming in each case a welded section 7.2, 8.2.

[0060] As is the case in its outer axial face 4b.1 of the second closure part 4b, the piston unit 2 has a recess in its outer end section 2.1, the inclination angle of which corresponds to the inclination angle of the conical end of the stud bolt.

[0061] The welds 7.4, 8.4 are arranged on the corresponding conical surfaces with inclination angles highlighted by dashed lines. [Explanation of symbols]

[0062] 1 cylinder 2 Piston Unit 2.1 Outer section 3 Cylinder tube 4a First closure part 4b Second closure part 4b.1 Outer axial plane 5a first cylinder tube end 5b Second Cylinder Tube End 6 Inside the cylinder 6.1 Working chamber 7 Rod-side threaded coupling module 7.1 Threaded Section of Rod-side Threaded Connection Module 7.2 Welded Sections of Rod-side Threaded Joint Modules 7.3 Longitudinal axis of the piston unit 7.4 Welds for Rod-side Threaded Joint Modules 8 Proximal Threaded Connection Module 8.1 Threaded Section of Proximal Threaded Joint Module 8.2 Welded Sections for Proximal Threaded Joint Modules 8.3 Longitudinal axis of the cylinder 8.4 Welds on Base Threaded Joint Modules

Claims

1. An actuating cylinder comprising a cylinder (1) and a piston unit (2), The cylinder (1) comprises a cylinder tube (3), a first closure part (4a) and a second closure part (4b), the cylinder tube (3) has a first cylinder tube end (5a) and a second cylinder tube end (5b); the first closure part (4a) is arranged on the first cylinder tube end (5a); the second closure part (4b) is arranged on the second cylinder tube end (5b); The cylinder tube (3) and the closure parts (4a, 4b) form a cylinder interior (6), the piston unit (2) defines at least one working chamber (6.1) in the cylinder interior (6), slides through the first closure part (4a), and has an outer end section (2.1); the actuating cylinder has a rod-side threaded coupling module (7) designed to be corrosion-resistant and having a threaded section (7.1) and a welded section (7.2); said threaded section (7.1) being designed to be coupled to a device to be actuated; the rod-side threaded coupling module (7) is welded to the outer end section of the piston unit (2) at the weld section (7.2) by a weld (7.4), and the threaded section is arranged on the longitudinal axis (7.3) of the piston unit; An actuating cylinder.

2. An actuating cylinder comprising a cylinder (1) and a piston unit (2), The cylinder (1) comprises a cylinder tube (3), a first closure part (4a) and a second closure part (4b), the cylinder tube (3) has a first cylinder tube end (5a) and a second cylinder tube end (5b); the first closure part (4a) is arranged at the first cylinder tube end (5a) and is designed as a guide closure part, said second closure part (4b) is arranged at said second cylinder tube end (5b) and is designed as a base closure part; The cylinder tube (3) and the closure parts (4a, 4b) form a cylinder interior (6), the piston unit (2) defines at least one working chamber (6.1) in the cylinder interior (6), slides through the first closure part (4a), and has an outer end section (2.1); the actuating cylinder has a proximal threaded coupling module (8) designed as a corrosion-resistant part and having a threaded section (8.1) and a welded section (8.2); said threaded section (8.1) being designed to be coupled to a device to be actuated; the proximal threaded coupling module (8) is welded at the weld section (8.2) to the outer axial surface (4b.1) of the second closure part (4b) by a weld (8.4), and The threaded section is arranged on the longitudinal axis (8.3) of the cylinder (1). An actuating cylinder.

3. The rod-side threaded connection module (7) or the base-side threaded connection module (8) is designed as a socket head bolt.

3. The actuating cylinder according to claim 1 or 2, characterized in that:

4. The rod-side threaded connection module (7) is designed as a hexagonal bolt.

4. The actuating cylinder according to claim 3, wherein:

5. the base threaded coupling module (8) is designed as a cylinder head screw and the welding section (8.2) is designed as a cylindrical screw head; said second closure part (4b) having a cylindrical bore hole in its outer axial surface (4b.1); the cylindrical screw head being form-fittingly radially received by the cylindrical bore; and The weld is formed as an axial ring weld.

4. The actuating cylinder according to claim 3, wherein:

6. The rod-side threaded connection module (7) or the base-side threaded connection module (8) are designed as zinc-plated screws or stainless steel screws.

3. The actuating cylinder according to claim 1 or 2, characterized in that:

7. The rod-side threaded connection module (7) or the base-side threaded connection module (8) is provided with a protective coating layer.

3. The actuating cylinder according to claim 1 or 2, characterized in that:

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