Method for forging a forged workpiece and workpiece manipulator for use in a method for die forging or radial forging of forged workpieces in a forging press

Abstract

The invention relates to a method for forging a forged workpiece (2) in a forging press (3) preferably designed as an open-die press or radial forging press, wherein the method comprises manipulating the forged workpiece (2) by means of a workpiece manipulator (1) having a workpiece gripper (5), wherein the workpiece gripper (5) has a chuck (6) that defines a clamping axis S for the forged workpiece (2), wherein the workpiece manipulator (1) performs a linear translational movement with the forged workpiece between press strokes of the forging press (3), wherein the method further comprises determining the position of at least the end (4) of the forged workpiece (2) clamped in the workpiece gripper (5) in the clamping axis S relative to a reference point on the forging press (3), in particular to the tools of the forging press (3), by means of at least one measuring system provided on or in the workpiece gripper (5).The invention further relates to a workpiece manipulator (1) for use in the method according to the invention.

Description

[0001] The invention relates to a method for forging a forged workpiece and to a workpiece manipulator for use in a method for open-die forging or radial forging of forged workpieces in a forging press, in particular for use with a method according to the invention.

[0002] The invention particularly relates to a method for forging a forged workpiece in a forging press preferably designed as an open-die press or radial forging press, wherein the method comprises the manipulation of the forged workpiece by means of a workpiece manipulator having a workpiece tongs, wherein the workpiece tongs have a chuck defining a clamping axis for the forged workpiece, wherein the workpiece manipulator performs a linear translational movement with the forged workpiece between press strokes of the forging press.

[0003] A workpiece manipulator or forging manipulator is known, for example, from DE 10 2012 217 650 A1. This document describes a forging manipulator with a tong carrier with a workpiece tong. The tong carrier is arranged in a translationally movable manipulator frame and can be variably positioned relative to the manipulator frame for handling a workpiece held in the workpiece tong.

[0004] Forging manipulators of the type mentioned in this publication are used in so-called open-die forging, in which the workpiece to be machined in a forging device designed as a forging press is held in a tong carrier of the forging manipulator and is brought into a desired relative position to the forging press by means of lifting, tilting or rotating movements of the tongs arranged in a manipulator frame of the forging manipulator in order to be formed in a defined manner by means of a press part of the forging device.

[0005] In radial forging presses, it is common practice to guide the forging manipulator linearly in or on a manipulator track. In a radial forging press, the ingot to be forged is formed by several, usually four, forging tools acting simultaneously and synchronously on the circumference of the ingot, while the forging manipulator holds the rear end of the ingot. This necessitates the forging manipulator gripping and holding the workpiece in the forging axis, whereby manipulation of the forged workpiece naturally occurs only in the translational axis of the forging manipulator.

[0006] For example, DE 10 2014 226 384 A1 discloses a loading system and method for radial forging presses. The loading system comprises a linear guide system for the forging manipulator, which is integrated into a manipulator track below the floor level of the forging manipulator.

[0007] Especially when forging stepped shafts, it is important to adjust the exact position of the steps to be provided in the forged workpiece by appropriately moving the workpiece manipulator. This has traditionally been achieved by determining the length of the forged workpiece using rulers or similar measuring devices and by appropriately moving the workpiece manipulator. This involves measuring a length or a partial length of the visible and unclamped forged workpiece relative to a position of the workpiece manipulator on the manipulator track.

[0008] It is fundamentally desirable to be able to determine the exact position of the workpiece relative to the tools of the forging press, especially in order to increase the accuracy of the process control.

[0009] The invention is therefore based on the object of providing a method of the type mentioned above, with which an exact length determination of at least partial lengths of the forged workpiece is possible. In particular, the invention is based on the object of being able to more precisely adjust a desired target geometry when forging stepped forged workpieces, in particular stepped shafts. Finally, the invention is based on the object of providing a workpiece manipulator for carrying out the method.

[0010] The object underlying the invention is achieved by a method having the features of claim 1 and by a workpiece manipulator having the features of claim 10. Advantageous embodiments of the invention emerge from the subclaims.

[0011] According to one aspect of the invention, a method for forging a forging workpiece in a forging press is provided, which comprises manipulating the forging workpiece by means of a workpiece manipulator comprising a workpiece tongs having a chuck that defines a clamping axis for the forging workpiece, wherein the workpiece manipulator imparts a linear translational movement to the forging workpiece between press strokes of the forging press, wherein the method is particularly characterized in that the determination of the position of at least one end of the forging workpiece clamped in the workpiece tongs in the clamping axis relative to a reference point on the forging press, in particular relative to tools of the forging press, is carried out by means of at least one measuring system provided on the workpiece tongs,with which in particular the distance of the end of the forged workpiece clamped in the workpiece tongs to a reference point on the workpiece manipulator is measured.

[0012] The method according to the invention can comprise the use of a workpiece manipulator in the form of a stationary manipulator or in the form of a forging robot, or also in the form of a manipulator that can be linearly movable on or in a manipulator track. The latter can be freely movable or rail-mounted.

[0013] If the workpiece manipulator is designed to be movable relative to the forging press, it can perform a linear translational movement with the forging workpiece between press strokes of the forging press.

[0014] The procedure known in the prior art assumes that the forged workpiece is clearly fixed in the workpiece gripper. During the forging process, the forged workpiece undergoes a change in shape such that the thickness or diameter of the forged workpiece is reduced, which is accompanied by a change in the length of the forged workpiece. It is unavoidable that the clamped end of the forged workpiece moves in the workpiece gripper, so that the length of the workpiece or a partial length of the forged workpiece cannot be determined with sufficient accuracy. This possible change in position of the clamped end of the forged workpiece in the chuck of the workpiece gripper is taken into account in the method according to the invention, so that the method enables an exact determination of the workpiece position in the workpiece gripper or manipulator gripper for the first time.This increases process efficiency, quality, and accuracy. Furthermore, it also saves time because time-consuming measurements with rulers or other measuring devices are no longer necessary.

[0015] An exact determination of the length of the forged workpiece can, for example, also be carried out by detecting the position of the free end of the forged workpiece, i.e. the end facing away from the workpiece manipulator.

[0016] Preferably, the distance between the clamped end of the forged workpiece and a reference point on the workpiece manipulator is measured. A reference point can be provided, for example, on the workpiece gripper or in the chuck of the workpiece gripper. Particularly preferably, the reference point is defined by the position of a sensor that is arranged in the clamping axis of the chuck and that, for example, as an optical sensor, has a clear view of the end of the forged workpiece. The position of the reference point is known from the known position of the workpiece manipulator relative to the forging press. This position can be determined using known sensors during the linear translational movement of the workpiece manipulator or of a manipulator frame that is driven and movable on a manipulator track. The manipulator frame can, for example, be rail-mounted and movable on the manipulator track.If the sensor is designed as a tactile sensor, for example, the sensor extends in the form of a stylus in the clamping axis of the chuck and is arranged centrally in the chuck so that its extended axis can engage with an end face of the forged workpiece facing the workpiece manipulator.

[0017] Advantageously, the distance of the clamped end of the forged workpiece to the reference point on the workpiece manipulator is measured optically and / or tactilely and / or by radar, and at least a partial length of the forged workpiece is determined taking into account a respective known position of the workpiece manipulator.

[0018] The position of the clamped end of the forged workpiece can be used, for example, to automatically control the strokes of the forging press. The position of the clamped end of the forged workpiece can be detected using radar, laser, a probe, a measuring probe, a measuring pin, or another light-section sensor.

[0019] The process is preferably carried out as an open-die forging process, preferably for forging stepped shafts according to a predetermined pass schedule.

[0020] For example, the position of the end of the forging workpiece can be used to determine the shoulder length of a stepped shaft as a forging workpiece.

[0021] The advantages of the method according to the invention are particularly valuable when forging stepped shafts, since in this case it is important to precisely position the shoulders in order to achieve the desired target geometry of the forged workpiece. The measured position in the end of the workpiece gripper or in the end of the workpiece gripper's chuck can be used to precisely adjust the shoulder lengths when forging shoulders.

[0022] The workpiece manipulator used in the method according to the invention is expediently designed so that only a single degree of manipulation freedom is possible, preferably in the forging axis or in the translation axis of the manipulator frame or parallel to the forging axis or to the translation axis.

[0023] The method according to the invention is particularly characterized by the feedback of the position of one end of the forged workpiece as an input variable to an automatic control system of the forging press. For example, according to the invention, automatic triggering of the presses above the forging press can be provided depending on measured position data or depending on length information determined therefrom. Alternatively, the length of the forged workpiece can be displayed to an operator of the forging press on the side facing the workpiece manipulator, so that the operator can manually trigger or control the press strokes according to the pass schedule.

[0024] In an expedient variant of the method, it can be provided to use the position of the forged workpiece and / or the length or partial length of the forged workpiece determined therefrom as an input variable in a computer-implemented model for calculating the deformation distribution of the forged workpiece.

[0025] A further aspect of the invention relates to a workpiece manipulator for use in a method for forging forged workpieces in a forging press, in particular in an open-die press or a radial forging press, in particular for carrying out the method described above.

[0026] The workpiece manipulator preferably comprises a workpiece gripper, which forms a chuck with a preferably fixed clamping axis extending along the forging axis, so that the forged workpiece can be manipulated with a linear translational movement. The workpiece manipulator according to the invention is characterized in that at least one measuring system is integrated into the workpiece gripper, which is designed to determine the clamped end of the forged workpiece relative to a reference point on the forging press, in particular relative to the forging tools of the forging press.

[0027] The workpiece manipulator can be designed as a stationary manipulator, a forging robot, or even as a manipulator that can be linearly movable on or within a manipulator track. The latter can be freely movable or rail-mounted.

[0028] The workpiece clamp is preferably attached to a manipulator frame that can be moved linearly on a manipulator track.

[0029] The manipulator frame can be rail-mounted and motor-driven and can be moved along the manipulator track.

[0030] An expedient embodiment of the workpiece manipulator according to the invention is characterized in that the measuring system comprises at least one measuring means which is designed to carry out a distance measurement which measures optically, tactilely or by means of radar the distance of the free end of the clamped end of the forged workpiece to a reference point on the workpiece manipulator, preferably on the collet and further preferably in the clamping axis of the chuck.

[0031] The measuring device can comprise at least one sensor selected from a group of sensors including laser sensors, radar sensors, laser scanners, light section sensors, measuring probes, measuring pins, and measuring sensors. For redundancy reasons, multiple sensors can be provided, in particular several different sensors whose data allows a plausibility check.

[0032] The workpiece manipulator can comprise at least one sensor that is inserted into a centrally arranged sensor receptacle of the chuck of the workpiece gripper. The sensor receptacle can be designed, for example, as a bore extending along the clamping axis of the chuck, located at a deepest point of the chuck, and offering a clear view of the end of the forged workpiece.

[0033] The invention is explained below using an embodiment shown in the drawing.

[0034] The drawing shows a workpiece manipulator 1 according to the invention, which feeds a forged workpiece 2 to a forging press 3 designed as an open-die forging press. In the described embodiment, the forged workpiece 2 is designed as a stepped shaft with a shoulder 20 of length L1. One end 4 of the forged workpiece 2 is held in a workpiece gripper 5 of the workpiece manipulator 1 and is firmly clamped there in a chuck 6 by means of gripper arms 7. The workpiece manipulator 1 comprises a manipulator frame 8 with a chassis 9, which is linearly movable in the direction of a translation axis X, for example, on rails (not shown) of a manipulator track 10.

[0035] A sensor 11, designed for example as a laser sensor, is arranged in the chuck 6 of the workpiece manipulator 1 or the workpiece tongs 5, which is aligned such that its measurement signal extends in a clamping axis S aligned parallel to the translation axis X. The sensor 11, which is held in a holder of the chuck 6 with a clear view of the end 4 of the forged workpiece 2, detects the distance between the bottom of the chuck as a reference point with a defined position on the workpiece manipulator 1 and the clamped end 4 of the forged workpiece 2. Via a known position of the workpiece manipulator 1 on the manipulator track 10, the distance between the end 4 of the forged workpiece 2 and the inlet of the forging press 3 and thus the length L2 of the forged workpiece 2 in front of the forging press 3 is known or can be determined.In the method according to the invention, the length L2 is taken into account as a variable in the control of the forging press 3. For example, the press operator can control the press strokes of the forging press 3 accordingly to maintain an exact length L1 for the shoulder 20 specified according to a pass schedule. As already mentioned above, the distance information or the length information can also be used for the automatic control of the forging press 2 and / or as an input variable in a computer-aided calculation model for calculating the deformation of the forged workpiece 2. List of reference symbols 1 workpiece manipulator 2 forged workpiece 20 paragraph 3 forging press 4 End of the forged workpiece 5 workpiece pliers 6 chucks 7 clamp arms 8 Manipulator frame 9 Chassis 10 Manipulator track 11 Sensor L1 Length of the heel L2 Length of the forged workpiece in front of the forging press X translation axis S clamping axis QUOTES CONTAINED IN THE DESCRIPTION

[0000] This list of documents submitted by the applicant was generated automatically and is included solely for the convenience of the reader. This list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions. Cited patent literature

[0000] DE 10 2012 217 650 A1

[0003] DE 10 2014 226 384 A1

[0006]

Claims

[1] Method for forging a forged workpiece (2) in a forging press (3) which is preferably designed as an open-die press or as a radial forging press, the method comprising manipulating the forged workpiece (2) by means of a workpiece manipulator (1) which has a workpiece tongs (5), the workpiece tongs (5) having a chuck (6) which defines a clamping axis S for the forged workpiece (2), the workpiece manipulator (1) imparting a linear translational movement to the forged workpiece (2) between press strokes of the forging press (3), the method further comprising determining the position of at least the end (4) of the forged workpiece (2) clamped in the workpiece tongs (5) in the clamping axis S relative to a reference point on the forging press (3), in particular to the tools of the forging press (3), by means of at least one measuring system provided on or in the workpiece tongs (5). [2] Method according to claim 1,characterized by that the distance of the clamped end (4) of the forged workpiece (2) to a reference point on the workpiece manipulator (1), in particular the workpiece tongs (5) and / or in the chuck (6) of the workpiece tongs (5), is measured. [3] Method according to one of claims 1 or 2, characterized by that the distance of the clamped end (4) of the forged workpiece (2) to a reference point on the workpiece manipulator (1) is measured optically and / or tactilely and / or by means of radar and at least a partial length L2 of the forged workpiece (2) is determined taking into account a respectively known position of the workpiece manipulator (1). [4] Method according to one of claims 1 to 3, characterized by the use of the position of the clamped end (4) of the forging workpiece (2) to automatically control the press strokes of the forging press (3). [5] Method according to one of claims 1 to 4, characterized bythat the position of the clamped end (4) of the forged workpiece (2) is determined by means of radar, laser, measuring sensor, measuring probe, measuring pin or light section sensor. [6] Method according to one of claims 1 to 5, characterized by that the process is carried out as an open-die forging process, preferably for forging stepped shafts according to a predetermined pass schedule. [7] Method according to one of claims 1 to 6, characterized by that the position is used to determine the shoulder length L1 of a stepped shaft as a forged workpiece (2). [8] Method according to one of claims 1 to 7, characterized by a feedback of the position as an input variable into a control system of the forging press (3). [9] Method according to one of claims 1 to 8, characterized by an automatic triggering of the press strokes of the forging press (3) depending on the measured position data. [10] Method according to one of claims 1 to 9, characterized by that the position is used as an input variable in a computer-implemented model for calculating or predicting the deformation distribution of the forged workpiece (2). [11] Workpiece manipulator (1) for use in a method for forging forged workpieces (2) in a forging press (3), in particular in an open-die press or a radial forging press, in particular for carrying out the method according to one of claims 1 to 8, with a workpiece tongs (5), wherein the workpiece tongs (5) form a chuck (6) with a preferably fixed clamping axis S, which extends in a forging axis, so that the forged workpiece (2) can be manipulated with a linear translational movement, characterized bythat at least one measuring system is integrated into the workpiece tongs (5), which is designed to determine the clamped end (4) of the forged workpiece (2) relative to a reference point on the forging press (3), in particular relative to the forging tools of the forging press (3). [12] Workpiece manipulator according to claim 11, which is designed as a stationary manipulator or as a forging robot or as a manipulator which can be moved linearly on or in a manipulator track (10). [13] Workpiece manipulator according to one of claims 1 to 12 characterized by that the workpiece clamp (5) is attached to a manipulator frame (8) which can be moved linearly on a manipulator track (10), [14] Workpiece manipulator (1) according to one of claims 11 to 13, characterized byin that the measuring system comprises at least one measuring means which is designed to carry out a distance measurement which measures optically, tactilely or by means of radar the distance of the clamped end (4) of the forged workpiece (2) to a reference point on the workpiece manipulator (1), preferably on the workpiece tongs (5) and further preferably in the clamping axis S of the chuck (6). [15] Workpiece manipulator (1) according to one of claims 11 to 14, characterized by that the measuring means comprises at least one sensor (11) which is selected from a group of sensors comprising laser sensors, radar sensors, laser scanners, light section sensors, measuring probes, measuring pins and measuring sensors. [16] Workpiece manipulator (1) according to one of claims 11 to 15, characterized by that at least one sensor (11) is inserted into a centrally arranged sensor holder of the chuck (6) of the workpiece clamp (5).

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