Radialpresse

Abstract

A radial press of yoke press design comprises a stationary yoke (1), a movable yoke (2), a press drive (3) that effects the closing movement of the movable yoke (2) relative to the stationary yoke (1), and a one-piece, ring-shaped frame (9) surrounding these components. The stationary yoke (1) and the movable yoke (2) together define a tool installation space in which a press tool (5) with a plurality of press jaws (6) arranged around a press axis is accommodated. The press drive (3) comprises at least two parallel-oriented hydraulic cylinder-piston units (10) spaced apart from each other transversely to the press axis. A drive carrier (12) is provided, which the frame (9) surrounds by at least 160° against a curved support surface (16) of the drive carrier (12).And the drive carrier (12) has a number of receptacles (38) corresponding to the number of hydraulic cylinder-piston units (10), into which the pistons (39) of the hydraulic cylinder-piston units (10) immerse.

Description

[0001] The present invention relates to a radial press in yoke press design, comprising a fixed yoke, a movable yoke, a press drive effecting the closing movement of the movable yoke relative to the fixed yoke and a one-piece, annularly closed frame surrounding these components, wherein the fixed yoke and the movable yoke together define a tool installation space in which a pressing tool with a plurality of pressing jaws arranged around a pressing axis is received.

[0002] Radial presses in yoke press design have been known for decades and have proven themselves in practical use. Reference can be made to DE 41 35 465 A1 as an example of the relevant state of the art. Yoke presses with a housing or frame structure featuring a lateral feed opening through which the workpiece can be inserted from the side into the opened pressing tool (cf. DE 199 40 744 A1 and DE 198 17 882 A1) simplify handling in various application situations or are even indispensable for certain applications. However, they reach their limits at very high pressing forces due to the risk of deformation of the (asymmetrical housing or frame structure). In this case, radial presses designed in yoke press design are advantageous, which either have a tie rod coupled to the movable yoke on each side of the tool installation space (cf. DE 41 35 465 A1, see above).) or a circumferentially closed frame structure coupled to the fixed yoke. Such radial presses, which also correspond to the generic design mentioned above, are known by name from US 8 266 968 B2, DE 199 12 976 A1, CA 2 005 264 A, and DE 10 2016 102 275 A1.

[0003] Given the increasing demand for radial pressing operations performed with very high pressing forces, the present invention aims to provide a generic radial press characterized by a particularly favorable power-to-weight ratio. In other words, the objective is to provide a generic radial press with a high ratio of the radial press's performance (in terms of maximum pressing force) to its weight. A favorable power-to-weight ratio in the above sense is particularly important for radial presses designed for particularly high pressing forces (e.g., more than 15,000 kN); this allows the manufacturing costs (which depend heavily on the amount of material used) to be kept within a reasonable range.

[0004] The task described above is solved by using a radial press of the generic type - the press drive comprises at least two parallel oriented hydraulic cylinder-piston units spaced apart from each other transversely to the press axis, - a drive carrier is provided, which the frame wraps around at least 160°, nestled against a curved support surface of the drive carrier, and - the drive carrier has a number of receptacles corresponding to the number of hydraulic cylinder-piston units, into which the pistons of the hydraulic cylinder-piston units are inserted.

[0005] Due to the synergistic interaction of its various design features, the radial press according to the invention is characterized by the possibility of a very uniform stress distribution with only minimal local stress peaks. As a result, even the reaction forces arising at very high pressing forces can be controlled with structures that—measured against the performance of the radial press and compared to radial presses with previously known designs—can be manufactured with relatively little material expenditure and thus cost-effectively. The comparatively low weight of the radial press—again measured against its performance—is also an immense advantage of the present invention.A further advantage of high practical relevance associated with the design of the radial press according to the invention is the possibility of optimizing the radial press without loss of performance with regard to particularly simple interchangeability of the yokes and components of the press drive.

[0006] According to a first preferred embodiment of the invention, the drive support surface defines a section of a circular cylinder. This not only has a direct, positive effect on the stress distribution occurring in the frame, but a further advantage of this design lies in the particularly simple possibility of a defined, deliberate slippage between the frame and the drive support in the event of a deliberately factored expansion of the frame during the pressing process. In this light, it is further advantageous if the frame and the drive support are only fixed to one another locally, namely at the apex of the frame, while the frame otherwise rests against the drive support surface in a sliding manner. The advantages described are particularly pronounced if the frame, nestled against the curved support surface of the drive support, wraps around it at 180°.

[0007] A further, highly advantageous development of the invention is characterized in that the cylinders of the hydraulic cylinder-piston units are an integrated part of the drive carrier, with the cylinders of the hydraulic cylinder-piston units forming the cylinders of the hydraulic cylinder-piston units in its receptacles. The static-mechanical strength requirements for the cylinders of the hydraulic cylinder-piston units are thus met by the receptacles formed integrally with the drive carrier. However, this does not preclude the internal lining of the cylinders of the hydraulic cylinder-piston units with a separate liner, particularly in the case of a drive carrier manufactured using a casting process such as gray cast iron. This development offers particular advantages when the press drive comprises exactly two hydraulic cylinder-piston units.It is also advantageous if there is a displaceability transverse to the axis of the respective hydraulic cylinder-piston unit between the pistons of the hydraulic cylinder-piston units and the movable yoke, for example, realized by a pair of sliding surfaces; in this way, possible transverse forces on the pistons are minimized, which contributes to mechanical protection of the hydraulic cylinder-piston units, thus extending their service life.

[0008] Particularly when the press drive comprises a large number of hydraulic cylinder-piston units, a different design for integrating the press drive into the drive carrier can prove very advantageous. This is where the hydraulic cylinder-piston units are separate elements whose cylinders are inserted into the mounts of the drive carrier. In this case, even commercially available cylinder-piston units can be used, which ideally rest on the drive carrier without any torque.The statement in the claim, according to which the pistons of the hydraulic cylinder-piston units may be immersed in the respective associated receptacle formed on the drive carrier, as the above explanations of a preferred embodiment of the invention show, can thus be (mis)understood to mean that the pistons functionally interact with the receptacles; in this respect, it is merely a matter of a geometric relationship.

[0009] Depending on the individual design of the radial press according to the invention, at least one hydraulic pressure intensifier is assigned to the hydraulic cylinder-piston units of the press drive. In typical applications of the present invention, this is preferably structurally integrated into the drive carrier by having a housing formed integrally with the rest of the drive carrier. However, in individual cases, it may also prove advantageous for the hydraulic pressure intensifier to be a separate component mounted on the drive carrier, although this typically results in a higher overall weight of the radial press.

[0010] According to the inventive support of the drive carrier on the frame, according to yet another preferred embodiment of the radial press according to the invention, it is advantageous if the frame, nestled against a curved support surface of the stationary yoke, wraps around the latter by at least 160°, particularly preferably 180°, whereby the yoke support surface can in particular describe a section of a circular cylinder. The advantages presented and explained above apply accordingly here.

[0011] Regarding the arrangement of the two yokes, according to yet another preferred embodiment of the invention, the fixed yoke forms a lower yoke and the movable yoke forms an upper yoke. This applies in particular to radial presses designed for particularly large workpieces (e.g., Ø > 500mm) and particularly high pressing forces (e.g., > 10,000 kN) that must be applied to them; in this case, the yokes have a substantial mass, which, when the movable yoke is arranged as the upper yoke, increases the pressing force.

[0012] According to yet another preferred embodiment of the present invention, the frame has two arc sections, each describing a 180° arc, and two tensile sections connecting these sections and parallel to each other and to the orientation of the hydraulic cylinder-piston units. Said orientation of the tensile sections ensures that they are free of shear stresses, i.e., are subjected exclusively to tensile stress. This, in turn, also contributes to optimal stress distribution and thus the best possible utilization of the material used. It is particularly advantageous if the extension of the frame parallel to the press axis is smaller, at least on some of the arc sections, than on the tensile sections.The greater extension of the frame parallel to the pressing axis in the area of ​​the two tension sections compared to the curved sections ensures increased resistance of the frame to deformations that could lead to limited quality of the radial pressing (e.g., conicity of the pressing). This is also contributed to if, according to yet another preferred development of the invention, guides for the movable yoke are provided in the area of ​​the tension sections of the frame. It is particularly advantageous if guide elements fixed to the movable yoke engage in associated grooves of the tension sections of the frame and are guided there for displacement. Such a design of the guide for the movable yoke does not hinder the desired, defined expansion of the tension sections during the pressing process.For this form of guiding the movable yoke, the frame design explained above, in which the tension sections are wider than the curved sections in some areas, parallel to the pressing axis, proves to be particularly advantageous. In individual cases, however, it may also be advantageous if the frame has the same extension parallel to the pressing axis throughout, i.e., on both its tension sections and its curved sections, and even if the tension sections are narrower than the curved sections.

[0013] According to yet another preferred development of the radial press according to the invention, in radial presses with a press drive comprising exactly two hydraulic cylinder-piston units, at least one advance and return stroke adjuster acting on the movable yoke is arranged on the drive support between the cylinders of the hydraulic cylinder-piston units. Particularly preferably, two (or even more) such advance and return stroke adjusters are provided in the form of hydraulic cylinder-piston units, which are oriented parallel and spaced apart from one another in the direction of the press axis. Preferably, a stiffening web of the drive support extends between two advance and return stroke adjusters, oriented transversely to the press axis, and at its end merges into its receptacles, possibly thus into the cylinders of the two hydraulic cylinder-piston units of the press drive formed by these.Particularly preferably, the at least one advance and return stroke adjuster is replaceable without further disassembly work; this enables the radial press to be adapted to different requirements or tasks without any significant effort.

[0014] Furthermore, it is highly advantageous if at least two, preferably four, position sensors are installed between the fixed yoke and the movable yoke, whose signals are transmitted to the press control system. This allows potential asymmetries in the pressing to be identified early on, before irreversible damage to the workpiece occurs, which in turn allows for correction of the pressing. This is a crucial factor, particularly given that the radial press according to the invention, due to its design, is primarily used for the radial forming of particularly large, complex, and expensive workpieces. By detecting a potential faulty radial forming process early on and exploiting the possibilities for corrective action, scrap can be avoided, which represents a very direct cost aspect.

[0015] In the following, the present invention will be explained in more detail with reference to two preferred embodiments illustrated in the drawing. Fig. 1 the radial press according to a first embodiment in perspective view, Fig. 2 a front view of the radial press according to Fig. 1, Fig. 3 a side view of the radial press according to the Fig. 1 and Fig. 2 from left, Fig. 4 a vertical section through the radial press according to the Fig. 1 to 3 along line IV-IV in Fig. 2, Fig. 5 a plan view of the radial press according to the Fig. 1 to 4, Fig. 6 a horizontal section through the radial press according to the Fig. 1 to 5 along the line VI-VI in Fig. 2 and Fig. 7 a horizontal section through the radial press according to the Fig. 1 to 6 along the line VII-VII in Fig. 2. In contrast, Fig. 8 a partially sectioned front view of the upper region of a radial press according to the invention according to a second embodiment.

[0016] The Fig. The radial press, designed in the yoke press style and illustrated in Figures 1 to 7 of the drawing, comprises a fixed yoke 1, a movable yoke 2, and a press drive 3 that effects the closing movement of the movable yoke 2 relative to the fixed yoke 1. The fixed yoke 1 and the movable yoke 2 together define a tool installation space 4 in which a pressing tool 5 with a plurality of pressing jaws 6 arranged around a pressing axis X is received. By means of support and control surfaces of the two yokes 1, 2 and the pressing jaws 6, which interact with one another in a known manner, a closing movement of the movable yoke 2 (arrow A) is converted into a radially inward movement of the pressing jaws 6 oriented in the direction of the pressing axis X. This concept, which constitutes the essence of yoke presses, and its constructive implementation are comprehensively described in the prior art and therefore require no further explanation here.

[0017] In the radial press shown, the fixed yoke 1 forms a lower yoke 7, and the movable yoke 2 forms an upper yoke 8. The press drive 3 is arranged above the upper yoke 8 and acts directly on it. The frictional connection (between the lower yoke 7 and the press drive 3) is achieved via a one-piece frame 9—namely, a mechanically reworked cast part—that surrounds the lower yoke 7, upper yoke 8, and press drive 3 in a closed ring.

[0018] The press drive 3 comprises two hydraulic cylinder-piston units 10 oriented parallel to one another with vertical axes parallel to the closing movement A of the upper yoke 8. The two cylinder-piston units 10 are arranged side by side, transversely to the press axis X, i.e., spaced apart from one another in a plane perpendicular to the press axis X. The two cylinders 11 of the hydraulic cylinder-piston units 10 are each formed by a receptacle 38 integrally formed on a drive support 12, similar to a downwardly open bushing; in this way, they are an integrated part of the drive support 12, which further comprises webs and ribs that stiffen the structure, in particular a stiffening web 13 extending transversely to the press axis X between the two receptacles 38 or the cylinders 11 formed by them, and merging into the latter at the ends.At the top, the drive carrier 12 is limited by an end arc 14 - widened in the orientation of the press axis X - whose outer surface 15 forms a curved support surface 16 for the frame 9. The end arc 14 has two extended foot sections 17 which merge into the bottoms 18 of the cylinders 11 of the two hydraulic cylinder-piston units 10. The curved support surface 16 on the end arc 14 merges into support surface sections 19 on the cylinders 11 of the hydraulic cylinder-piston units 10. The entire drive carrier support surface 20, i.e. the curved support surface 16 on the end arc 14 together with the two support surface sections 19 on the cylinders 11, each forming an extension, lies on a 180° section of a circular cylinder.In this way, the frame 9 has an upper arc section 21 which describes a 180° arc and wraps around the drive carrier 12 to 180°, nestled against the drive carrier support surface 16.

[0019] The outer surface 22 of the fixed yoke 1, i.e., in this case, the lower yoke 7, facing away from the tool installation space 4, describes—in a manner comparable to the drive carrier 12 explained above—a yoke support surface 23, which also lies on a 180° segment of a circular cylinder. And the frame 9 has a lower curved section 24, which describes a 180° arc and, nestled against the curved yoke support surface 23, wraps around the lower yoke 7 at 180°. It should be noted that the two curved sections 21, 24 of the frame 9 rest flat against the drive carrier support surface 16 and the yoke support surface 23, respectively; However, they are not fixed to the drive carrier 12 or the lower yoke 7 in a way that would hinder or even prevent load-induced expansion of the respective curved section 21, 24 under slip on the support surface 16, 23 of the drive carrier 12 or the lower yoke 7.In this respect, the position of the drive carrier 12 and the lower yoke 7 on the frame 9 is secured only at the upper vertex of the upper curved section 21 and the lower vertex of the lower curved section 24, respectively, and specifically solely by clamping by means of an upper pair of claws 25 fixed to the drive carrier 12 and a lower pair of claws 26 fixed to the lower yoke 7. Holes, in particular threaded holes on the curved sections 21, 24 of the frame 9 are thus avoided.

[0020] The frame 9 further comprises two tension sections 27 that connect the two curved sections 21, 24 to one another and are parallel to one another and to the orientation of the hydraulic cylinder-piston units 10. A widening of the two tension sections 27 relative to the curved sections 21, 24 such that the extension of the frame 9 parallel to the pressing axis X is less at least on some of the curved sections 21, 24 than at the tension sections 27, increases the rigidity of the frame 9 about a horizontal axis oriented transversely to the pressing axis X and transversely to the direction of movement A of the upper yoke 8, and thus counteracts tilting of the lower yoke 7 and the drive carrier 12 relative to one another. The corresponding widened regions of the two tension sections 27 are also designed to guide the (movable) upper yoke 8. For this purpose, the tension sections 27 of the frame 9 have grooves 28 extending parallel to the direction of movement A of the upper yoke 8.Guide elements 29 in the form of guide plates 30 fixed to the upper yoke 8 engage (movably) into these. Thus, for guiding the upper yoke 8 to the frame 9, no threaded holes or other bores are required in the frame 9. This supports the integrity of the frame and thus promotes an optimal, uninterrupted flow of force.

[0021] The hydraulic cylinder-piston units 10 of the press drive 3 are designed as single-acting hydraulic cylinders. The upper yoke 8 is raised to open the radial press by means of two separate return stroke adjusters 31 acting on the upper yoke 8. These are arranged between the cylinders 11 of the two hydraulic cylinder-piston units 10. They are designed as hydraulic cylinder-piston units 32, which are oriented parallel to one another at a distance from one another in the direction of the press axis X. The cylinders 33 of the two return stroke adjusters 31 are connected to the drive carrier 12, namely by ribs 34, which, in the form of an inverted T-profile, project laterally from the stiffening web 13 and extend between the two cylinders 11 of the hydraulic cylinder-piston units 10 of the press drive 3.

[0022] The return stroke adjusters 31, designed as combined rapid and return stroke adjusters, also perform an initial, comparatively high-speed closing movement of the upper yoke 8 during the phase until the pressing jaws 6 of the pressing tool 5 rest against the workpiece inserted into it. During this phase, the hydraulic cylinder-piston units 10 of the press drive 3 are switched to a post-suction mode, in which hydraulic fluid flows from the two overhead post-suction tanks 36—each flanged to the drive carrier 12 via a valve block 35—into the expanding working spaces of the hydraulic cylinder-piston units 10.

[0023] Two electrical displacement transducers 37 are located between the lower yoke 7 and the upper yoke 8, whose signals are fed to the machine control system. Two additional displacement transducers 37 can be arranged in a mirror image on the other end face of the radial press.

[0024] The radial press according to the second embodiment, to which Fig. 8 of the drawing, the upper area is illustrated in a partially sectioned front view, is explained directly from the above explanations of the Fig. 1 to 7 illustrated first embodiment.

[0025] The press drive 3' here comprises three hydraulic cylinder-piston units 10', each with a cylinder 11' and a piston 39'. These cylinder-piston units 10' represent separate components, i.e., physically independent of the drive carrier 12'. They are each inserted into a receptacle 38' integrated into the drive carrier 12', i.e., partially received in a free space 41 formed by the respective receptacle 38'. The load-transmitting, end-face support of the cylinders 11' on the drive carrier 12' is torque-free, i.e., via mutually abutting sliding surfaces with a spherical cap geometry.

[0026] In this embodiment, the two return stroke adjusters 31' are offset diagonally from the center of the radial press, namely the return stroke adjuster provided on the side facing away from the viewer, of which Fig. 8 the piston rod 40 is shown, to the left in a plane lying between the left cylinder-piston unit 10'a and the middle cylinder-piston unit 10'b and the provided on the side facing the viewer, in Fig. 8 non-recognizable return stroke adjusters to the right into a plane lying between the middle cylinder-piston unit 10'b and the right cylinder-piston unit 10'c.

[0027] It should be noted that in the Fig. 1 to 7 shown details such as the valve blocks 35 and the suction tanks 36 in Fig. 8 are not shown for the sake of simplicity, clarity and clarity. Obviously, similar components can also be used in the radial press according to Fig. 8 must be implemented.

[0028] In a modified variant of the embodiment according to Fig. 8, it is possible to arrange the three hydraulic cylinder-piston units 10'a, 10'b, and 10'c of the press drive not in one plane, but rather to offset the middle cylinder-piston unit 10'b in the direction of the press axis relative to the plane defined by the left cylinder-piston unit 10'a and the right cylinder-piston unit 10'c. Through targeted, controlled individual loading of the various hydraulic cylinder-piston units, the center of the resulting force exerted by the press drive 3' on the movable yoke 2 can be shifted in the direction of the press axis.This enables - during the pressing process and thus without correcting the position of the workpiece in the pressing tool - an influence on the pressing force conditions, namely to compensate for a possible asymmetry, such as that which occurs, for example, due to an asymmetrical workpiece geometry and / or an off-center position of the workpiece in the pressing tool - and due to differing measurement results of the displacement sensors 37 provided on the front and rear of the radial press (cf. . Fig. 2) can be detected. It is understood that this modification can also be used in radial presses according to the invention having at least three hydraulic cylinder-piston units, in which the cylinders of the hydraulic cylinder-piston units - as in the case of the Fig. 1 to 7 - are an integrated part of the drive carrier.

Claims

[1] Radial press in yoke press design, comprising a fixed yoke (1), a movable yoke (2), a press drive (3, 3') effecting the closing movement of the movable yoke (2) relative to the fixed yoke (1) and a one-piece, annularly closed frame (9) surrounding these components, wherein the fixed yoke (1) and the movable yoke (2) together define a tool installation space (4) in which a pressing tool (5) with a plurality of pressing jaws (6) arranged around a pressing axis (X) is received, characterized by the following features: - the press drive (3, 3') comprises at least two parallel-oriented hydraulic cylinder-piston units (10, 10') spaced apart from one another transversely to the press axis (X); - a drive carrier (12, 12') is provided, which the frame (9) wraps around at least 160°, nestled against a curved support surface (16) of the drive carrier (12, 12'); - the drive carrier (12, 12') has a number of receptacles (38, 38') corresponding to the number of hydraulic cylinder-piston units (10, 10'), into which the pistons (39, 39') of the hydraulic cylinder-piston units (10, 10') are inserted. [2] Radial press according to claim 1, characterized by that the drive carrier support surface (16) describes a section of a circular cylinder. [3] Radial press according to claim 1 or claim 2, characterized by that the cylinders (11) of the hydraulic cylinder-piston units (10) are an integrated part of the drive carrier (12), in that its receptacles (38) form the cylinders (11) of the hydraulic cylinder-piston units (10). [4] Radial press according to claim 3, characterized by that between the pistons (39) of the hydraulic cylinder-piston units (10) and the movable yoke (2) there is a displaceability transversely to the axis of the respective hydraulic cylinder-piston unit (10). [5] Radial press according to claim 3 or claim 4, characterized by that the cylinders (11) of the hydraulic cylinder-piston units (10) are lined internally with a separate liner. [6] Radial press according to one of claims 3 to 5, characterized by that the press drive (3) comprises exactly two hydraulic cylinder-piston units (10). [7] Radial press according to claim 1 or claim 2, characterized by that the hydraulic cylinder-piston units (10') are separate elements whose cylinders (11') are inserted into the receptacles (38') of the drive carrier (12'). [8] Radial press according to claim 7, characterized by that the cylinders (11') of the hydraulic cylinder-piston units (10') are supported torque-free on the drive carrier (12'). [9] Radial press according to one of claims 1 to 8, characterized by that the drive unit (3, 3') has a hydraulic pressure intensifier. [10] Radial press according to claim 9, characterized by that the hydraulic pressure intensifier is structurally integrated into the drive carrier (12, 12'). [11] Radial press according to one of claims 1 to 10, characterized by that the frame (9) is nestled against a curved support surface (23) of the fixed yoke (1) and wraps around it to at least 160°. [12] Radial press according to claim 11, characterized by that the yoke support surface (23) describes a section of a circular cylinder. [13] Radial press according to one of claims 1 to 12, characterized by that the fixed yoke (1) forms a lower yoke (7) and the movable yoke (2) forms an upper yoke (8). [14] Radial press according to one of claims 1 to 13, characterized bythat the frame (9) has two arc sections (21, 24) each describing a 180° arc and two tension sections (27) connecting these to one another and parallel to one another and to the orientation of the hydraulic cylinder-piston units. [15] Radial press according to claim 14, characterized by that the extension of the frame (9) parallel to the pressing axis (X) is smaller at least on some of the curved sections (21, 24) than on the tension sections (27). [16] Radial press according to claim 14 or claim 15, characterized by that guides for the movable yoke (2) are provided in the area of the tension sections (27) of the frame. [17] Radial press according to claim 16, characterized by that guide elements (29) fixed to the movable yoke (29) engage in associated grooves (28) of the tension sections (27) of the frame (9). [18] Radial press according to one of claims 1 to 17, characterized bythat between two cylinders (11, 11') of the hydraulic cylinder-piston units (10, 10') at least one advance and return stroke adjuster (31) acting between the drive carrier (12, 12') and the movable yoke (2) is arranged. [19] Radial press according to claim 18, characterized by that at least two advance and return stroke adjusters (31) in the form of hydraulic cylinder-piston units (32) are provided, which are spaced apart from one another in a parallel orientation in the direction of the press axis (X) and whose respective cylinders (33) are arranged on the drive carrier (12, 12'). [20] Radial press according to claim 18 or claim 19, characterized by that at least one rapid and return stroke adjuster (31) can be replaced without further disassembly work. [21] Radial press according to one of claims 1 to 20, characterized by that at least two, preferably four displacement sensors (37) act between the fixed yoke (1) and the movable yoke (2).

Images