Working cylinder

Abstract

The invention relates to a working cylinder comprising a cylinder (10) and a piston unit (20), wherein the cylinder (10) has a cylinder tube (13), a guide closure part (11) and a bottom closure part (12), wherein: the cylinder tube (13) has a first cylinder tube end (13.1) and a second cylinder tube end (13.2); the guide closure part (11) is located on the first cylinder tube end (11.1), the bottom closure part (12) is located on the second cylinder tube end (13.2), and the cylinder tube (13) and the closure parts (11, 12) form a cylinder interior (14); the piston unit (20) forms at least one working chamber (15) in the cylinder interior (14) and penetrates the guide closure part (11) slidingly; and the working cylinder has a pivot bearing (30) which has at least one pivot-bearing journal (31) which is radially arranged in a receiving bore (11.1) in the guide closure part (11) and is welded together with the guide closure part (11) by means of a circumferential annular laser weld seam (34).

Description

[0001] Working cylinder

[0002] The invention relates to a working cylinder with a pivot bearing arranged on the cylinder.

[0003] From the state of the art, pivotally mounted working cylinders are known as such by means of pivot bearings additionally attached to the cylinder.

[0004] Depending on the application, it may be necessary to pivot the working cylinder on the head closure part so that it can perform a circular compensating movement, for example, at the end of the piston rod. For this purpose, it is known to flange additional pivot bearings onto the working cylinder, which can be achieved by welding, in particular MAG welding, or by screwing. A significant disadvantage of the welded version is that a high level of heat energy is introduced into the fully assembled cylinder, which has a thermally damaging effect on the sliding and sealing elements and only allows such elements to be installed later, for example. Screwing leads to undesirable material stresses or weakening in the area of ​​the cylinder barrel and regularly requires allowances in the dimensioning to avoid deformations that could impair function.

[0005] In both variants, the additional space required for the pivot bearings adversely affects the cylinder's installation size. Furthermore, additional space must usually be considered for the arrangement of the pressure fluid connections in the cylinder head area.

[0006] The object of the invention is to provide a working cylinder with a pivot bearing which is robust and space-saving and can be manufactured cost-effectively.

[0007] Confirmation copy The problem is solved by the features listed in patent claim 1. Preferred developments arise from the subclaims.

[0008] The working cylinder with pivot bearing pin according to the invention comprises a cylinder and a piston unit as basic components, corresponding to the basic structure of a working cylinder known from the prior art. The working cylinder can be available in various cylinder types, such as a differential cylinder, plunger cylinder, pull cylinder, or other types.

[0009] The cylinder consists of a cylinder tube, a guide closure part, and a base closure part. The cylinder tube has a first cylinder tube end and a second cylinder tube end. The guide closure part is arranged at the first cylinder tube end. Correspondingly, the base closure part is arranged at the second cylinder tube end. The arrangement of the two closure parts is designed such that they are pressure-tightly connected to the respective cylinder tube ends. To connect them, the two closure parts are preferably laser-welded to the cylinder tube along their circumferential common contact surface in a pressure-tight manner. The cylinder tube and the closure parts thus form a cylinder interior. The cylinder interior is pressure-tight and is designed to absorb the typical working pressure of hydraulic systems.

[0010] The piston unit forms at least one working chamber in the cylinder interior. The cylinder interior is understood to be the interior of the cylinder formed by the closure parts and the cylinder tube, in which the pressure medium is located during intended use. The piston is also arranged in the cylinder interior. So that the working cylinder can act and generate movement, the guide closure part is slidably penetrated by the piston unit. The working cylinder according to the invention also has a pivot bearing. The pivot bearing, in turn, has at least one pivot bearing pin. The pivot bearing pin is arranged laterally, preferably radially, on the cylinder along a transverse axis. A transverse axis is understood to be any axis lying transversely to the longitudinal axis of the working cylinder and thus to the stroke axis.The pivot bearing preferably consists of two radially opposite, eccentrically oriented pivot bearing journals located on a common transverse axis.

[0011] The pivot bearing serves as a pivot point for mounting the cylinder in the assembly to be actuated, where the cylinder can pivot about the transverse axis. This allows an assembly to be actuated even if its counter pivot point, which can be coupled, in particular, by a spherical bearing at the outer end of the piston rod, describes a movement that deviates from the linear stroke axis, for example, an arcuate movement.

[0012] The guide closure part has a receiving bore in which the at least one pivot bearing pin is arranged. This enables a positive force transmission between the pivot bearing pin and the guide closure part. Advantageously, the pivot bearing pin can also be designed as a structurally simple cylindrical part that can be efficiently manufactured by turning.

[0013] According to the invention, the pivot bearing journal, which is joined in the receiving bore of the guide closure part, is materially coupled by means of a circumferential laser ring weld. This combination of positive and material-locking coupling ensures that the pivot bearing is reliably and stably integrated into the guide closure part. A receiving bore in the guide closure part creates a precise fit between the surface sections of the pivot bearing journal to be welded and the corresponding surface sections of the guide closure part, which enables laser welding while overcoming the disadvantages of MAG welding of the journals to the cylinder barrel according to the prior art.

[0014] The coupling according to the invention has in particular the following advantages.

[0015] The combination of a mounting bore and a laser ring weld seam enables welding with a particularly low heat input and thus a correspondingly small heat-affected zone. This allows for the assembly of thermally sensitive components, such as sealing rings or guides, prior to welding, thus creating manufacturing advantages. Even a cylinder with already welded closure parts and an inserted piston unit can be fitted with the pivot bearing.

[0016] Furthermore, due to the small heat-affected zone, the mounting bore can advantageously be arranged comparatively deep and close to the thermally sensitive components, which advantageously enables a high proportion of positive force transmission.

[0017] The solution according to the invention thus makes it possible to bring the pivot bearing axis particularly close to the guide-side end of the cylinder and thus reduces the minimum distance between the pivot bearing and the counter-articulation point actuated by the piston unit of the working cylinder in a retracted position of the working cylinder.

[0018] This advantageously reduces the required working cylinder length and the material used for the working cylinder and advantageously saves the necessary installation space in the assembly to be actuated.

[0019] Furthermore, in contrast to a MAG welding of the journals on the cylinder tube according to the state of the art, the laser ring weld seam does not have a significant overhang of welding material on the outer weld line, so that the assembly to be actuated can be accommodated in the pivot bearing axis axially directly up to the outer limit of the guide closure part, so that the required installation space is also reduced and, in addition, a more favorable force transmission geometry is present, so that the size of the pivot bearing journals can be further reduced.

[0020] In an advantageous further development, the working cylinder is characterized in that the pivot bearing pin forms a pressure medium connection and a pressure medium channel, which forms a pressure medium-carrying connection between the pressure medium connection and the working chamber, is arranged as a pivot bearing channel at least in sections in the pivot bearing pin.

[0021] The pressure medium connection according to this development is understood to be the external access to the pressure medium channel. The pressure medium channel according to this development is understood to be the pressure medium-carrying connecting channel between the pressure medium connection and the working chamber in its entirety. The pressure medium channel can, in particular, consist of the pivot bearing channel and the closure part channel, or in special designs, it can also be formed by the pivot bearing channel alone.

[0022] According to this further development, the pivot bearing pin is functionally integrated and simultaneously used as part of the pressure medium-carrying system. The integration of the pressure medium connection and the pressure medium channel into the pivot bearing provides important advantages. In particular, a further reduction in the overall length of the working cylinder is possible, since the pivot pin and the pressure medium connection do not require separate positions on the outside of the cylinder. Furthermore, the integration also saves weight and material, since the pressure medium connection and the pivot bearing pin do not have to be provided as separate components. According to a further advantageous development, the working cylinder is characterized in that the pivot bearing channel is connected to a closure part channel of the guide closure part.

[0023] According to this refinement, the pressure medium channel consists of the pivot bearing channel and the closure part channel. To transmit the pressure medium, which is guided via the pressure medium connection and through the pivot bearing channel into the working chamber, the pivot bearing channel is connected to a closure part channel of the guide closure part. This advantageously allows an optimized position for the pivot bearing pin to be selected without having to consider direct access to the working chamber. The closure part channel can be manufactured through a preferably axial bore in the guide closure part, providing a connection between the pivot bearing channel and the working chamber.

[0024] According to a further advantageous development, the working cylinder is characterized in that the pivot bearing channel is arranged concentrically in the pivot bearing journal. Advantageously, the pivot bearing channel is thus located at the pressure medium connection on the pivot axis.

[0025] Preferably, the pivot axis corresponds exactly to the normal of the transverse axis to the main longitudinal axis of the working cylinder. The center axis of the pivot bearing pin also lies on the axis passing through the center of the pressure medium connection.

[0026] This allows the connection for the pressure medium supply to be implemented using either flexible or rigid lines. A rigid line is possible because, regardless of the pivoting of the working cylinder, the positional relationship to the pivot bearing pin remains unchanged, thus eliminating the need for a flexible section to compensate for the distance between the pivot axis and the line connection. A rotating coupling or screw connection is sufficient. Maintenance-intensive flexible parts can be eliminated.

[0027] Even when connecting via flexible supply lines, the advantage is that only torsional deformation needs to be accommodated, which can also be completely absorbed by a coupling or screw connection. This also reduces the stress on the material of a hydraulic hose or other flexible pressure line.

[0028] In addition, the concentric arrangement means that only the zone of the pivot pin is hollow, which is subject to less mechanical stress anyway.

[0029] According to a next advantageous development, the working cylinder is characterized in that the receiving bore has a conical outer section with a conicity angle and an inner section and that the laser ring weld seam is arranged on the outer section and has the conicity angle as a weld seam angle.

[0030] By means of the combination of a conical outer section and an adjoining inner section of a different inclination, preferably a cylindrical section, it is ensured in a surprisingly simple manner that the weld root of the laser ring weld seam neither reaches the pivot bearing channel nor the closure part channel and thus cross-sectional changes or deformations of the pivot bearing channel or, depending on the design, also of the closure part channel are avoided.

[0031] By locating the laser ring weld on the outer section rather than the inner section, the heat-affected zone is further spaced from the thermally sensitive components, particularly at the piston rod passage through the guide closure part, while maintaining the same depth of the mounting hole for the pivot bearing pin. Furthermore, the conical outer section allows for both precise centering and precise axial positioning of the pivot bearing pin, which is advantageous from a manufacturing technology perspective.

[0032] The tapered outer section also allows for the optimal transfer of the transverse forces acting on the pivot pin into the solid material of the guide closure part. Effects such as high bearing stresses or stress peaks due to manufacturing defects can thus be eliminated or minimized. The cross-sectional change due to the conicity also optimizes material usage, as the required material cross-section is only present where it is actually needed due to the load.

[0033] The taper angle corresponds to the weld seam angle a. This describes the inclination to the pivot bearing axis and is preferably 10° to 60°, and particularly preferably 25° to 45°.

[0034] According to a further advantageous development, the working cylinder is characterized in that the pivot bearing has a further pivot bearing pin, which is arranged opposite the first pivot bearing pin on the guide closure part. This further pivot bearing pin shares a common pivot bearing axis with the first pivot bearing pin, which is arranged transversely to a main longitudinal axis of the cylinder. This makes it possible to accommodate the cylinder in the assembly to be actuated without buckling loads on the piston unit and, at the same time, to dimension the pivot bearing pins smaller.

[0035] The invention is illustrated as an embodiment by means of Fig. 1 sectional view of the working cylinder with pivot bearing and integrated pivot bearing channel

[0036] Fig. 2 Sectional view of the working cylinder according to Fig. 1 as an enlarged section

[0037] Fig. 3 Sectional view of the working cylinder according to another embodiment, explained in more detail as an enlarged section.

[0038] Identical reference symbols in the various figures refer to identical features or components. These reference symbols are used in the description even if they are not shown in the respective figure.

[0039] Fig. 1 shows a sectional view of the working cylinder in a first embodiment in an overall view.

[0040] The working cylinder is designed here as a differential working cylinder. The cylinder 10 comprises the cylinder barrel 13 and, arranged thereon at the first cylinder barrel end 13.1, the guide closure part 11 and the bottom closure part 12 arranged at the second cylinder barrel end 13.2. The piston unit 20 is designed here as an assembly consisting of a piston and piston rod.

[0041] In this exemplary embodiment, the pivot bearing 30 is formed by the pivot bearing pin 31 and the further pivot bearing pin 32, both of which are arranged orthogonally on the common pivot bearing axis 33 and at the same time radially to the main longitudinal axis 16. The pivot bearing pin 31 is inserted into the receiving bore 11.1 and welded there by means of the circumferential laser ring weld 34. The pivot bearing channel 41.1 is arranged in the pivot bearing pin 31 in the form of a coaxial bore that completely penetrates the pivot bearing pin 31 and leads outwards to the pressure medium connection 40 and inwards to the closure part channel 41.2. The closure part channel 41.2 is manufactured as a bore that creates a connection for the pressure medium passage from the inner cylinder side of the guide closure part 11, axially parallel to the main longitudinal axis 16, to the receiving bore 11.1. The pivot bearing channel 41.1 and the locking part channel 41.2 together form the pressure medium channel 41, which connects the pressure medium connection 40 with the working chamber 15.

[0042] Fig. 2 shows an enlarged section of the area of ​​the guide closure part 11 with the pivot bearing pin 31 and the pressure medium channel 41 arranged there. In particular, it can be seen that the laser ring weld 34 is arranged on the outer section 11.1 and that the inner section 11.2 is arranged in the receiving bore without a laser weld and can thus contribute to the force transmission between the pivot bearing pin 31 and the guide closure part 11 by means of positive locking.

[0043] The laser ring weld 34 is positioned at a weld angle of approximately 30° to the pivot bearing axis 33, so that the weld root can only reach the inner section 11.2, but not the bottom of the receiving bore 11.1. The pressure medium channel 41 thus connects the pressure medium connection 40 to the working chamber 15 without being impaired by the welding of the pivot bearing pin 31.

[0044] Fig. 3 shows in a schematic sectional view as a detailed section of the working cylinder in an alternative embodiment the area of ​​the guide closure part 11.

[0045] The pivot bearing 30 here has a pivot bearing pin 31 and another pivot bearing pin 32, without a pressure medium channel 41 being integrated. Both pivot bearing pins 31, 32 are of identical construction and are arranged on the guide closure part 11 with a laser ring weld seam 34.

[0046] The guide closure part 11 and the pivot bearing pins 31, 32 are positioned relative to each other via the outer section 11.2 and the inner section 11.3 using the respective mounting bore 11.1. They are arranged coaxially on the pivot bearing axis 33 and also perpendicular to the main longitudinal axis 16 of the cylinder 10.

[0047] Reference symbols used

[0048] 10 cylinders

[0049] 11 Guide closure part

[0050] 11.1 Mounting hole

[0051] 11.2 Outdoor section

[0052] 11.3 Interior section

[0053] 12 Bottom closure part

[0054] 13 Cylinder barrel

[0055] 13.1 first cylinder tube end

[0056] 13.2 second cylinder tube end

[0057] 14 Cylinder interior

[0058] 15 work space

[0059] 16 Main longitudinal axis

[0060] 20 piston unit

[0061] 30 swivel bearings

[0062] 31 pivot pin

[0063] 32 additional pivot pins

[0064] 33 Swivel bearing axis

[0065] 34 Laser ring weld

[0066] 40 Pressure medium connection

[0067] 41 Pressure medium channel

[0068] 41.1 Pivot bearing channel

[0069] 41.2 Closure part channel a Weld angle

Claims

Patent claims 1. Working cylinder, comprising a cylinder (10) and a piston unit (20), wherein the cylinder (10) has a cylinder tube (13), a guide closure part (11) and a bottom closure part (12), wherein the cylinder tube (13) has a first cylinder tube end (13.1) and a second cylinder tube end (13.2), the guide closure part (11) is arranged at the first cylinder tube end (11.1) and the bottom closure part (12) is arranged at the second cylinder tube end (13.2), and the cylinder tube (13) and the closure parts (11, 12) form a cylinder interior (14), wherein the piston unit (20) forms at least one working chamber (15) in the cylinder interior (14) and slidably passes through the guide closure part (11), and wherein the working cylinder has a pivot bearing (30) which has at least one pivot bearing pin (31) which is arranged on the guide closure part (11) in a mounting hole (11.1) is arranged radially and is welded to the guide closure part (11) by means of a circumferential laser ring weld seam (34).

2. Working cylinder according to claim 1, characterized in that the pivot bearing pin (31) has a pressure medium connection (40) and that a pressure medium channel (41), which forms a pressure medium-carrying connection between the pressure medium connection (40) and the working chamber (15), is arranged at least in sections as a pivot bearing channel (41.1) in the pivot bearing pin (31).

3. Working cylinder according to claim 2, characterized in that the pivot bearing channel (41.1) is connected to a closure part channel (41.2) of the guide closure part (11).

4. Working cylinder according to one of the preceding claims 2 or 3, characterized in that the pivot bearing channel (41.1) is arranged concentrically in the pivot bearing pin (31).

5. Working cylinder according to one of the preceding claims, characterized in that the receiving bore (11.1) has a conical outer section (11.2) with a conicity angle and an inner section (11.3) and that the laser ring weld seam (34) is arranged on the outer section (11.2) and has a weld seam angle a which corresponds to the conicity angle.

6. Working cylinder according to one of the preceding claims, characterized in that the pivot bearing (30) has a further pivot bearing pin (32) which is arranged opposite the pivot bearing pin (31) on the guide closure part (11) and has a common pivot bearing axis (33) with the pivot bearing pin (31) which is arranged transversely to a main longitudinal axis (16) of the cylinder (10).

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