Actuating cylinder
The actuating cylinder with a pivot bearing journal and annular laser weld seam addresses thermal and material issues, providing a compact, efficient, and cost-effective solution by integrating the pivot bearing and pressure medium connection, reducing thermal damage and material stress while optimizing space usage.
Patent Information
- Application Number
- JP2025541729
- Authority / Receiving Office
- JP · JP
- Patent Type
- Applications
- Current Assignee / Owner
- Priority Date
- 2023-01-27
- Filing Date
- 2023-12-14
- Publication Date
- 2026-02-10
AI Technical Summary
Existing pivotally mounted actuating cylinders face issues with thermal damage, material stress, and increased installation space due to traditional welding methods, and require separate locations for pivot bearings and pressure medium connections, leading to inefficient space usage and potential deformation.
An actuating cylinder design with a pivot bearing journal that uses a circumferential annular laser weld seam, allowing for a secure, space-saving, and cost-effective installation by integrating the pivot bearing and pressure medium connection into the cylinder structure, minimizing heat input and reducing material consumption.
The design reduces thermal damage, minimizes material stress, saves installation space, and optimizes force transmission geometry, while enabling efficient manufacturing and integration of heat-sensitive components, thus enhancing the overall efficiency and compactness of the actuating cylinder.
Smart Images
Figure 2026504886000001_ABST
Abstract
Description
[Technical Field]
[0001] The present invention relates to an actuation cylinder having a pivot bearing disposed in the cylinder. [Background technology]
[0002] Pivotally mounted actuating cylinders are known as such from the prior art by means of pivot bearings additionally attached to the cylinder.
[0003] Depending on the application, it may be necessary to pivotally mount the actuating cylinder on the head closure, for example, to allow for circular compensating movements at the piston rod end. For this purpose, it is known to flange an additional pivot bearing onto the actuating cylinder, which can be done by welding, especially MAG welding, or by screwing. The main drawback of the welded variant is the introduction of a large amount of thermal energy into the fully assembled cylinder, which can have a thermally damaging effect on the sliding and sealing elements, and the fact that such elements can only be installed retroactively. Screwed connections require regular dimensional tolerances to avoid undesirable material stresses or weakening in the cylinder tube area and functionally damaging deformations.
[0004] In both variants, the additional space required for the pivot bearing has a negative effect on the installation size of the cylinder. Furthermore, additional installation space must be regularly provided for the pressure medium connections in the head region of the cylinder. Summary of the Invention
[0005] SUMMARY OF THE INVENTION It is an object of the present invention to provide an actuating cylinder with a pivot bearing that is robust, space-saving and can be produced cost-effectively.
[0006] This problem is solved by the features of patent claim 1. Preferred further developments are derived from the subclaims.
[0007] The actuation cylinder with pivot bearing journal according to the invention comprises as its basic components a cylinder and piston unit in a manner corresponding to the basic structure of actuation cylinders known from the prior art, which may be provided as various cylinder types, in particular as differential cylinders, plunger cylinders, pull cylinders or other types.
[0008] The cylinder comprises a cylinder tube, a guide closure portion, and a bottom closure portion. The cylinder tube has a first cylinder tube end and a second cylinder tube end. The guide closure portion is positioned on the first cylinder tube end. Correspondingly, the bottom closure portion is positioned on the second cylinder tube end. The two closure portions are arranged to be pressure-tightly connected to their respective cylinder tube ends. For this connection, the two closure portions are preferably pressure-tightly laser-welded to the cylinder tube along their common circumferential contact surfaces. The cylinder tube and closure portion thus form a cylinder interior. The cylinder interior is designed to be pressure-tight and absorb typical operating pressures of hydraulic systems.
[0009] The piston unit forms at least one working chamber in the cylinder interior. The cylinder interior is understood to be the internal space of the cylinder formed by the closure part and the cylinder tube, in which the pressure medium is accommodated during intended use. A piston is also disposed in the cylinder interior. The piston unit slidably passes through the guide closure part to enable the working cylinder to operate and to generate motion.
[0010] Furthermore, the actuation cylinder according to the present invention comprises a pivot bearing. The pivot bearing further comprises at least one pivot bearing journal. The pivot bearing journal is arranged laterally, preferably radially, on a transverse axis to the cylinder. A transverse axis is understood to be any axis extending transversely to the longitudinal axis of the actuation cylinder, and thus to the stroke axis. The pivot bearing preferably consists of two radially opposed, eccentrically oriented pivot bearing journals arranged on a common transverse axis.
[0011] The pivot bearing serves as an articulation point for positioning the cylinder within the assembly to be actuated, so that the cylinder can be pivoted about a lateral axis, meaning that the assembly can also be actuated when its opposite articulation point, which may be coupled in particular by a spherical bearing at the outer end of the piston rod, performs a movement that deviates from the linear stroke axis, for example an arcuate movement.
[0012] The guide closure part has a receiving bore hole in which at least one pivot bearing journal is disposed. This arrangement enables reliable force transmission between the pivot bearing journal and the guide closure part. Advantageously, the pivot bearing journal 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 inserted into the receiving bore of the guide closure part is securely material-bonded by a circumferential annular laser weld seam. This combination of form fit and secure material bond ensures that the pivot bearing is securely and stably installed in the guide closure part. According to the invention, the precise fit between the surface section of the pivot bearing journal to be welded and the corresponding surface section of the guide closure part is created by the receiving bore in the guide closure part, making laser welding possible and thus overcoming the drawbacks of MAG welding of journals on cylinder tubes according to the prior art.
[0014] The coupling according to the invention offers the following advantages in particular:
[0015] The combination of the receiving bore and the annular laser weld seam allows for welding with particularly low energy input per unit length, so heat is applied only to a correspondingly small area. This design allows heat-sensitive components such as sealing rings or guides to be installed before welding, thus creating advantages in terms of manufacturing technology. Even cylinders with already welded closures and inserted piston units can be fitted with additional pivot bearings in this way.
[0016] Additionally, the small heat affected area allows the receiving bore holes to be located relatively deep and close to heat sensitive components, thus advantageously allowing for a high percentage of form fit force transfer.
[0017] The solution according to the invention therefore makes it possible to bring the pivot bearing axis particularly close to the guide-side end of the cylinder, thus reducing the minimum distance between the pivot bearing in the retracted position of the actuating cylinder and the opposite articulation point acted upon by the piston unit of the actuating cylinder.
[0018] This solution advantageously reduces the length of the required actuation cylinder and the material consumption of the actuation cylinder, and advantageously saves corresponding installation space within the assembly to be actuated.
[0019] Furthermore, unlike prior art MAG welding of journals on cylinder tubes, the annular laser welded seam does not have significant protrusions of weld material at the outer weld seam line, allowing the actuated assembly to be mounted axially directly within the pivot bearing axis up to the outer boundary of the guide closure portion, thereby also reducing the required installation space and achieving a more favorable force transmission geometry, which in turn allows for further reduction in the size of the pivot bearing journal.
[0020] In an advantageous further development, the actuating cylinder is characterized in that the pivot bearing journal forms a pressure medium connection and that a pressure medium channel forming a pressure medium conveying connection between the pressure medium connection and the actuating chamber is at least partially arranged in the pivot bearing journal as a pivot bearing channel.
[0021] The pressure medium connection according to this further development is understood to be an external access to the pressure medium channel. The pressure medium channel according to this further development is understood to be a pressure medium-carrying connection channel in its entirety between the pressure medium connection and the working chamber. The pressure medium channel can in particular consist of a pivot bearing channel and a closure part channel or, in special designs, can also be formed solely by the pivot bearing channel.
[0022] According to this further development, the pivot bearing journal is also used as part of the pressure medium conveying system in a functionally integrated manner. Integrating the pressure medium connection and the pressure medium channel into the pivot bearing offers important advantages. In particular, the pivot journal and the pressure medium connection do not require separate locations on the outside of the cylinder, which allows for a further reduction in the overall length of the actuating cylinder. Furthermore, the integration also saves weight and material, since the pressure medium connection and the pivot bearing journal do not need to be provided as separate components.
[0023] According to a further advantageous development, the actuating cylinder is characterized in that the pivot bearing channel is connected to a closure part channel of the guide closure part.
[0024] According to this development, the pressure medium channel consists of a pivot bearing channel and a closure part channel. The pivot bearing channel is connected to the closure part channel of the guide closure part to transfer the pressure medium guided through the pivot bearing channel via the pressure medium connection into the working chamber. This design has the advantage that an optimized position of the pivot bearing journal can be selected without having to provide direct access to the working chamber. The closure part channel can be generated by a preferably axial bore hole in the guide closure part, which provides the connection between the pivot bearing channel and the working chamber.
[0025] According to a further advantageous development, the actuating cylinder is characterized in that the pivot bearing channel is arranged coaxially in the pivot bearing journal, and is therefore advantageously positioned on the pivot axis at the pressure medium connection.
[0026] Preferably, the pivot axis corresponds exactly to a transverse axis perpendicular to the main longitudinal axis of the actuating cylinder. The central axis of the pivot bearing journal lies on an axis passing through the centre of the pressure medium connection.
[0027] The connection for the pressure medium supply can therefore be implemented using both flexible and rigid lines. Rigid lines are possible because, despite any pivoting of the actuating cylinder, there is no change in its position relative to the pivot bearing journal, so no flexible areas are needed to compensate for the distance between the pivot axis and the line connection. A rotatable coupling or a screw connection is already sufficient. No high-maintenance flexible parts are needed.
[0028] Connections with flexible supply lines also have the advantage that only torsional deformations have to be accommodated, which can also be fully accommodated by couplings or threaded connections, which also reduces the stress on the material of the hydraulic hose or other flexible pressure line.
[0029] In addition, the concentric arrangement means that only the area of the pivot bearing journal, which is in any case subject to less mechanical stress, has a hollow design.
[0030] According to a further advantageous development, the actuating cylinder is characterized in that the receiving bore has a conical outer section with a conical angle and an inner section, and an annular laser welded seam is arranged on the outer section, the conical angle being the welded seam angle.
[0031] The combination of a conical outer section followed by an inner section of different inclination, preferably a cylindrical section, ensures in a surprisingly simple manner that the weld root of the annular laser welded seam does not reach either the pivot bearing channel or the closure part channel, thus avoiding changes or deformations in the cross section of the pivot bearing channel or, depending on the design, also the closure part channel.
[0032] As a result of the annular laser weld seam being located on the outer section rather than the inner section, the heat affected zone is also kept a greater distance from heat sensitive components, particularly in the piston rod passage through the guide closure portion, while the receiving bore holes in the pivot bearing journals are maintained at the same depth.
[0033] In addition, the conical outer section of the pivot bearing journal allows for precise centering and accurate axial positioning, which is advantageous in terms of manufacturing technology.
[0034] The conical outer section also allows the lateral forces acting on the pivot journal to be optimally transferred to the solid material of the guide closure. In this way, the effects of high bore-bearing stresses or stress peaks due to manufacturing defects can be eliminated or minimized. Furthermore, the change in cross section due to the conical shape optimizes material consumption, as the required material cross section is provided only at points where it is actually required by the load.
[0035] The weld seam angle α corresponds to the conical angle, which describes the inclination relative to the pivot bearing axis and is preferably between 10° and 60°, particularly preferably between 25° and 45°.
[0036] According to a further advantageous development, the actuating cylinder is characterized in that the pivot bearing comprises a further pivot bearing journal arranged opposite the first pivot bearing journal in the guide closure part, the further pivot bearing journal having a common pivot bearing axis with the first pivot bearing journal and arranged transversely to the main longitudinal axis of the cylinder. This design allows the cylinder to be accommodated in an assembly for actuation without buckling stresses on the piston unit, and at the same time allows the pivot bearing journal to be dimensioned smaller.
[0037] The invention is explained in more detail by way of exemplary embodiments with the aid of the following figures. [Brief explanation of the drawings]
[0038] [Figure 1] FIG. 10 is a cross-sectional view of an actuation cylinder having a pivot bearing and an integrated pivot bearing channel. [Figure 2] 2 is a cross-sectional view of an enlarged detail of the actuation cylinder according to FIG. 1; FIG. [Figure 3] FIG. 10 is a cross-sectional view of an enlarged detail of an actuation cylinder according to another embodiment.
[0039] Here, the same reference numbers in the various figures refer to the same features or components. Reference numbers are also used in the description even if they are not shown in the associated figures.
[0040] FIG. 1 is a cross-sectional view showing the entire working cylinder according to the first embodiment.
[0041] Here, the actuating cylinder is designed as a differential actuating cylinder. The cylinder 10 comprises a cylinder tube 13, a guide closure part 11 arranged on a first cylinder tube end 13.1, and a bottom closure part 12 arranged on a second cylinder tube end 13.2. Here, the piston unit 20 is designed as an assembly consisting of a piston and a piston rod.
[0042] In this embodiment, the pivot bearing 30 is formed by a pivot bearing journal 31 and a further pivot bearing journal 32, each of which is arranged on a common pivot bearing axis 33, perpendicular and at the same time radial to the main longitudinal axis 16. The pivot bearing journal 31 is inserted into the receiving bore 11.1 and is welded there by a circumferential annular laser weld seam 34.
[0043] The pivot bearing channel 41.1 is arranged in the pivot bearing journal 31 in the form of a coaxial borehole that passes completely through the pivot bearing journal 31 and leads outwardly to the pressure medium connection 40 and inwardly to the closure part channel 41.2. The closure part channel 41.2 is designed as a borehole that forms a connection axially parallel to the main longitudinal axis 16 from the inside of the cylinder of the guide closure part 11 to the receiving borehole 11.1 for the passage of pressure medium. The pivot bearing channel 41.1 and the closure part channel 41.2 together form the pressure medium channel 41 that connects the pressure medium connection 40 to the working chamber 15.
[0044] 2 shows an enlarged cross-sectional view of the region of the guide closure part 11 in which the pivot bearing journal 31 and the pressure medium channel 41 are arranged. In particular, it can be seen that the annular laser welded seam 34 is arranged in the outer section 11.1, and that the inner section 11.2 without the laser welded seam is arranged in the receiving borehole and can therefore contribute to the force transmission between the pivot bearing journal 31 and the guide closure part 11 by a form-fit connection.
[0045] The annular laser welded seam 34 is arranged at a weld seam angle of approximately 30° relative to the pivot bearing axis 33 so that the root of the welded seam can only reach the inner section 11.2 and not the bottom of the receiving borehole 11.1. In this way, the pressure medium channel 41 connects the pressure medium connection 40 to the working chamber 15 without being obstructed by the welding of the pivot bearing journal 31.
[0046] FIG. 3 shows a detailed cross-sectional view of the actuation cylinder in an alternative exemplary embodiment, showing the area of the guide closure part 11.
[0047] In this embodiment, the pivot bearing 30 comprises a pivot bearing journal 31 in which the pressure medium channel 41 is not integrated here and a further pivot bearing journal 32. Both pivot bearing journals 31, 32 are of identical construction and are arranged in the guide closure part 11 by an annular laser welded seam m34.
[0048] The guide closure part 11 and the pivot bearing journals 31, 32 are positioned relative to one another by their respective receiving bores 11.1 through the outer section 11.2 and the inner section 11.3. They are arranged coaxially on the pivot bearing axis 33 and perpendicular to the main longitudinal axis 16 of the cylinder 10. [Explanation of symbols]
[0049] 10 cylinders 11 Guide closure part 11.1 Receptor Borehole 11.2 Outer Section 11.3 Inner Section 12 Bottom closure 13 Cylinder tube 13.1 First Cylinder Tube End 13.2 Second Cylinder Tube End 14 Inside the cylinder 15 Working chamber 16 Main longitudinal axis 20 Piston unit 30 Pivot bearing 31 Pivot bearing journal 32 Further pivot bearing journals 33 Pivot bearing axis 34 Annular laser welded seam 40 Pressure medium connection 41 Pressure medium channel 41.1 Pivot bearing channel 41.2 Closure Channels α Weld seam angle
Claims
1. An actuating cylinder comprising a cylinder (10) and a piston unit (20), The cylinder (10) has a cylinder tube (13), a guide closure portion (11), and a bottom closure portion (12), 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 positioned on the first cylinder tube end (13.1), the bottom closure part (12) is positioned 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 slidably passes through the guide closure part (11); the actuating cylinder has a pivot bearing (30) radially arranged in a receiving bore hole (11.1) in the guide closure part (11) and having at least one pivot bearing journal (31) welded to the guide closure part (11) by a circumferential annular laser weld seam (34), Actuating cylinder.
2. The pivot bearing journal (31) is provided with a pressure medium connection (40), and a pressure medium channel (41) forming a pressure medium conveying connection between the pressure medium connection (40) and the working chamber (15) is at least partially arranged in the pivot bearing journal (31) as a pivot bearing channel (41.1). characterized in that The actuating cylinder according to claim 1 .
3. The pivot bearing channel (41.1) is connected to the closure part channel (41.2) of the guide closure part (11). characterized in that The actuating cylinder according to claim 1 .
4. The pivot bearing channel (41.1) is coaxially arranged within the pivot bearing journal (31). characterized in that 4. The actuating cylinder according to claim 2 or 3.
5. The receiving bore (11.1) comprises a conical outer section (11.2) having a conical angle and an inner section (11.3), and the annular laser weld seam (34) is disposed in the outer section (11.2) and has a weld seam angle α corresponding to the conical angle. characterized in that An actuating cylinder according to any one of claims 1 to 4.
6. The pivot bearing (30) comprises a further pivot bearing journal (32) arranged opposite the pivot bearing journal (31) in the guide closure part (11) and having a common pivot bearing axis (33) with the pivot bearing journal (31), the common pivot bearing axis (33) being arranged transversely to the main longitudinal axis (16) of the cylinder (10). characterized in that An actuating cylinder according to any one of claims 1 to 5.