Machine head, roller burnishing device and method for necking a pilot hole

Abstract

The present invention relates to a machine head, a roller burnishing device comprising the machine head, and a method for necking out a pilot hole (44) in a metallic hollow body. The roller burnishing device (100) has a drive device (120) with an associated control device (125) which is designed to move the machine head (10) in various operating modes. The roller burnishing device according to the invention is characterized in that it has a machine head receiving space (112) which is delimited at least in sections by a conical inner wall (114). The receiving space (112) serves to receive the machine head (10) according to the invention. A preferably conical guide surface (13) at a free end of a tool receiving device (14) of the machine head is brought into contact with the conical inner wall (114) of the machine head receiving space (112).The mandrel (20) can be deflected in the radial direction (R) relative to the rotation axis (MA) of the rolling device (100) in accordance with a relative position between the machine head (10) and the inner wall (114) of the machine head receiving space (112).

Description

The invention relates to a machine head, a rolling device and a method for necking out a pre-hole in a metallic hollow body.The invention also relates to a corresponding computer program product.Rolling devices of this type are fundamentally known in the prior art, in particular from the international patent application WO 81 / 02119. The rolling device disclosed therein consists of a drill for inserting the pre-hole into the metallic hollow body. The drill is formed cylindrically with an axis of rotation. The drill carries on its periphery a machine head receiving device with a machine head. The machine head is formed from a base body (adjustment member) which is rotatable about the axis of rotation. On the surface of the downwardly tapering base body, spiral guide grooves are formed, in which tool receiving devices (gripping extensions) for mandrels (mining memories) are arranged displaceably. By displacing the tool holding devices with the mandrels along the spiral-shaped grooves, the mandrels are displaced with respect to the base body and its rotational axis both in the radial and in the axial direction. The mandrels are clamped in their tool receiving devices in such a way that they are aligned past the drill and cross each other in a pictorial manner.Rolling devices in the form of bead rolling machines are also known, having the features of the preamble of claim 9 for forming beads on the periphery of pipes.Proceeding from this prior art, the object of the invention is to provide an alternative machine head, an alternative rolling device and an alternative method for necking out a pre-hole in a metallic hollow body, and a corresponding alternative computer program product.This object is achieved with respect to the machine head by the subject matter of claim 1, with respect to the rolling device by the subject matter of claim 9, with respect to the method by the steps according to claim 11 and with respect to the computer program product by claim 15. All the devices according to the invention are designed to be structurally simpler than the devices in the prior art and the method according to the invention can be used more flexibly for various applications.Specific advantageous embodiments of the machine head according to the invention, of the rolling device according to the invention and of the method according to the invention are the subject matter of the respective dependent claims.A total of 10 figures are attached to the description, wherein FIG. 1 shows the machine head according to the invention in a perspective illustration; FIG. 2 shows the machine head in a side view; FIG. 3 shows a metallic hollow body with a pre-hole introduced; FIG. 4 shows the rolling device according to the invention in a longitudinal section from a first viewing direction with the mandrel in a starting position; FIG. 5 is a view of the underside of the machine head with the mandrel in the starting position; FIG. 6 shows the rolling device with the mandrel moved into a retraction position; FIG. 7 shows a view of the underside of the machine head with the mandrel in a position rotated through 90° with respect to its retraction position; FIG. 8 shows the rolling device with the mandrel moved into its removed position; FIG. 9 shows a longitudinal section through the rolling device with the mandrel, retracted into an extended position for forming the neck at the edge of the pre-hole in the hollow body; and FIG. 10 shows the degrees of freedom of the mandrel that can be realized with the rolling device according to the inventionshows.The invention is described in detail below with reference to the figures in the form of exemplary embodiments. In all the figures, the same technical elements are denoted by the same reference numerals.FIG. 1 shows the machine head 10 according to the invention, which substantially consists of two parts, namely a base body 12 and a tool receiving device 14. The base body is designed in the form of a disk for accommodation in a rolling device described from FIG. 4. The tool receiving device 14 serves for the detachable receiving of a tool 20, in particular in the form of a mandrel. The mandrel is typically a cylindrical rotationally symmetrical pin which is preferably further preferably gradually tapered in its diameter towards its free end; see also FIG. 10.As can also be seen in FIG. 2, the disk-shaped base body 12 has a central axis and the tool receiving device 14 is designed to keep the mandrel 20 aligned at a predetermined angle α to the central axis M of the base body. Specifically, the angle α between the central axis M of the base body and the longitudinal axis L of the mandrel is measured.The tool holding device 14 can be displaced on the base body 12 in the radial direction to the central axis M relative to the base body 12. For this purpose, the tool-holding device 14 is guided in guide strips 19 which are mounted on the base body 12. These guide strips 19 are L-shaped in cross section and thus ensure that the tool holding device 14 is fixed relative to the base body in the direction of the central axis M, i.e. cannot be displaced.According to a first exemplary embodiment, the tool receiving device 14 is designed to receive the mandrel 20 with its longitudinal axis L, aligned with the central axis M of the base body 12.According to a further exemplary embodiment, the tool receiving device 14 is designed to provide a freewheel for the tool or the mandrel 20, wherein the freewheel permits a rotation of the mandrel about its own longitudinal axis L. This offers the advantage that the mandrel can roll on the edge of the pre-hole in the embodiment of the neck according to the invention and described later, so that the friction between the mandrel and the edge of the pre-hole and thus the wear of the mandrel during the neck-out are substantially minimized.For the purpose of changing the tool or mandrel, the tool receiving device 14 can provide a lock 15 for locking the freewheel for the mandrel.The said angle α, at which the longitudinal axis of the mandrel is inclined with respect to the central axis M of the base body, is between 30° and 60°, preferably between 40° and 50°, or it is further preferably 45°. The tool receiving device 14 is designed to receive the tool 20 in a detachable manner.FIG. 3 shows, by way of example and schematically, a metallic hollow body 40, for example in the form of a tube, in the wall of which a pre-hole 44 is introduced, for example by drilling or milling. This is assumed to be the case when carrying out the process according to the invention and is thus referred to below as "preliminary hole". The hollow body 40 shown in FIG. 4 corresponds to the initial state before a neck is formed on the edge of the pre-hole 44 with the machine head according to the invention, the rolling device according to the invention and the method according to the invention, as described below.FIG. 4 shows the rolling device 100 according to the invention in a longitudinal section from a first viewing direction. The rolling device 100 has a machine head receiving device 110 which spans a machine head receiving space 112 with an inner wall 114 which is conical at least in sections. The machine head 10 is accommodated in the machine head accommodation space, which in turn has accommodated the mandrel 20 in its tool accommodation device 14. The rolling device 100 furthermore has a drive device 120, which, controlled by the control device 125, is designed to move the machine head 10 in at least one of the operating modes:i) in the form of a rotation of the machine head about the central axis MA of the rolling device 100;ii) in the form of an axial displacement of the machine head 10 along the central axis MA of the rolling device 100; and / oriii) for moving the tool receiving device 14 of the machine head 10 in the form of a radial displacement with respect to the central axis MA of the rolling device 100.The axis of rotation MA of the rolling device 100 preferably coincides with the central axis M of the machine head 10. The operating modes mentioned can be carried out not only one after the other in time, but also simultaneously, depending on the individual case.The different operating modes assume that the machine head receiving device 110 and the machine head 10 themselves can be controlled within the receiving device independently of one another by the drive device 120. The individual controls relate in particular to a translatory or axial movement along the axis of rotation MA of the rolling device and / or a rotation about this axis of rotation. Of course, the machine head receiving device 110 and the machine head 10 can also be synchronously controlled and moved.The tool receiving device 14 has a preferably conically designed guide surface 13 which, when the rolling device 100 is assembled, bears against the conical inner wall 114 of the machine head receiving space 112 or is supported there. The tool receiving device 14 is preferably braced or pressed with a spring against the conical inner wall 114 in the radial direction to the axis of rotation MA. This means: depending on how the machine head 10 is positioned or moved axially in the direction of the axis of rotation MA with respect to the machine head receiving device 110 and in particular with respect to its conical inner wall 114, the tool receiving device 14 is moved or advanced in the radial direction, i.e. transversely to the axis of rotation MA.In FIG. 4, the tool receiving device 14 is positioned with its guide surface 13 on the conical inner wall 114 of the machine head receiving space 112 in such a way that the tip of the mandrel 20 is positioned in a starting position above the pre-hole 44 to be necked out in the metallic hollow body 40. The metallic hollow body is clamped in a clamping device 50.FIG. 5 shows a view of the machine head 10 from below with a view of the clamped mandrel 20 in its starting position 17 according to FIG. 4 It can be seen in particular that the machine head 10 is accommodated in the machine head receiving space 112. The machine head receiving space 112 is defined by the machine head receiving means 110. The machine head 10 can be seen to have its base body 12 and the tool holding device 14. Furthermore, the guide strips 19 can also be seen, between which the tool receiving device 14 is mounted so as to be displaceable in the radial direction R relative to the base body 12.The process of the present invention will be described below in a stepwise manner with reference to Figs. 4 to 10.According to a first method step a), the machine head 10, as shown in FIGS. 4 and 5, is installed in the machine head receiving device 110 of the rolling device 100. Then, according to a method step b), the tool, i.e. the mandrel 20, is detachably clamped into the tool receiving device 14 of the machine head 10. In the clamped state, the mandrel is preferably fixed in the tool receiving device 14 in the direction of its longitudinal axis L. Preferably, however, it is also rotatable about its longitudinal axis L in the clamped state, i.e. mounted in a freewheeling manner.According to a method step c), the metallic hollow body 40 with the pre-hole 44 to be necked out is clamped in the clamping device 50 in a fixed manner. According to a method step d), the rolling device 100 with the mandrel 20 is positioned in a fixed position in a starting position 17, as shown in FIGS. 4 and 5, relative to the metallic hollow body 40 or to the pre-hole 44 to be necked out.According to a method step e), the mandrel 20 is then preferably retracted into the pre-hole 44 without rotation, as shown in FIG. 6. This is done primarily by axially displacing the machine head 10 together with the mandrel 20 along the central axis MA of the rolling device 100 according to the operating mode ii) of the drive device 120 thereof. The retraction is effected, for example, until the tip of the mandrel 20 is at a distance of about one third of the respective diameter of the hollow body 40 from the wall of the hollow body. In the case of large necks, in which a strongly elliptical pre-hole has been milled into the wall of the hollow body, the mandrel can, as stated, be introduced into the pre-hole by purely axial displacement or displacement of the machine head 10 along the central axis MA of the rolling device. This is the case, for example, with necked-out portions of collars having an inside diameter of 28 mm to 54 mm on pipes having precisely these diameters. In the case of necked-out portions whose inside diameter is smaller than the diameter of the hollow body, in particular in the form of the tube, the mandrel 20 must be moved into the pre-hole 44 in a diagonal movement. This diagonal movement can be realized by superimposing said axial displacement of the machine head 10 with a simultaneously occurring radial feeding of the mandrel by radially displacing the tool receiving device 14 relative to the base body. This is necessary because the pre-hole shape is round rather than elliptical with small neck diameters. This is the case, for example, when forming a neck of a clear diameter of 8 mm on a pipe of a diameter of 28 mm. In addition, when collars with small inside diameters are necked out, the mandrel is not inserted into the tube so deeply, that is to say less than one third of the respective tube diameter. With the method step e), the mandrel is moved from its starting position 17 into a retraction position 27 in the pre-hole 44.According to a subsequent method step f), the machine head 10 with the clamped mandrel 20 is set in rotation about its central axis M according to the operating mode i) of the drive device 120 of the rolling device 100. The mandrel 20 then performs a tumbling movement about the central axis M. FIG. 7 shows the machine head 10 with the mandrel 20 clamped in from below. It is a snapshot of the mandrel during its wobbling motion. FIG. 7 shows the mandrel in a position in which the mandrel, with the machine head 10, is rotated or twisted through 90° with respect to its position shown in FIG. 6 about the central axis M.Subsequently, the tumbling mandrel is displaced under the edge of the pre-hole 44 according to method step g), as shown in FIG. 8. This is effected by radially displacing the tool receiving device 14 with the tumbling mandrel 20 with respect to the central axis MA of the drive device 120 or the rolling device 100 according to its operating mode iii). Thus, in the course of the method step g), the mandrel 20 is displaced from its retraction position 27 into a removed position 37 below the edge of the pre-hole.Finally, the finish according to method step h) is formed by pulling out the tumbling mandrel from the pre-hole 44 by axially retracting the machine head while maintaining the removed position 37 of the mandrel 20, the edge of the pre-hole 44 being pulled up to form the finish and the finish forming in the form of a flange on the pre-hole outwards of the hollow body 40; see FIG. 9.According to one exemplary embodiment of the method according to the invention, the radially offset position 37 of the mandrel relative to the central axis MA of the rolling device 100 can be changed in the radial direction during the extraction of the tumbling mandrel 20 from the pre-hole according to method step h). This offers the advantage that even necks with variable inside diameter can be formed.According to a further exemplary embodiment of the method according to the invention, the mandrel 20 is mounted rotatably about the axis of rotation MA and the central axis M about its longitudinal axis during its tumbling movement. Then, the mandrel 20 can roll on the edge of the pre-hole 44 during the pulling-up according to method step h), whereby the friction between the edge of the pre-hole and the mandrel and the wear of the mandrel are advantageously significantly reduced.FIG. 10 illustrates the degrees of freedom that can be realized with the rolling device 100 according to the invention for the mandrel 20 for carrying out the method according to the invention.Finally, the invention relates to a computer program product which can be loaded directly into the memory of a digital computer and comprises software code sections with which the steps according to the method according to the invention, in particular according to one of Claims 11 to 14, are carried out when the computer program product runs on the computer.List of reference characters10 Machine head 12 Base body 13 Guide surface 14 Tool receiving device 15 Blocking of the freewheel 17 Starting position 19 Guide strips 20 Tool, in particular mandrel 27 Retracted position 37 Removed position 40 Hollow body 44 Pre-hole 50 Clamping device 100 Rolling device 110 Machine head receiving device 112 Machine head receiving space 114 Conical inner wall of the machine head receiving space 120 Drive device 125 Control device α Angle L Longitudinal axis of the tool or mandrel M Central axis of the base body MA Rotational axis of the rolling device R Radial directionReferences included in the specificationThis list of documents cited by the applicant has been produced in an automated manner and is only included for the better information of the reader. The list is not part of the German patent application or utility model application. The DPMA does not take any adhesion for any faults or omissions.Patent Literature citedWO 81 / 02119

[0003]

Claims

Machine head (10) comprising: a base body (12) having a central axis (M) for receiving in a rolling device (100); and a tool receiving device (14) connected to the base body (12) for receiving a tool (20), for example in the form of a mandrel, at a predetermined angle (α) to the central axis (M) of the base body (12), wherein the tool receiving device (14) is connected to the base body (12) such that it can be displaced in the radial direction (R) to the central axis (M); wherein the tool receiving device (14) is designed to receive the tool (20) in a displacement-proof manner with respect to its longitudinal axis (L); characterized in that the tool receiving device (14) is fixed relative to the base body in the direction of the central axis.Machine head (10) according to Claim 1, characterized in that the tool receiving device (14) is designed to receive the tool (20) with its longitudinal axis (L) aligned with the central axis (M) of the base body (12).Machine head (10) according to one of the preceding claims, characterized in that the tool receiving device (14) has a freewheel for the tool (20), wherein the freewheel is designed to allow rotation of the tool (20) about its own longitudinal axis (L).Machine head (10) according to claim 3, characterized in that the tool receiving device (14) optionally comprises a lock (15) for optionally locking the freewheel for the tool (20) during a tool change.Machine head (10) according to one of the preceding claims, characterized in that the predetermined angle (α) is in an angle range between 30° and 60°, preferably between 40° and 50° or more preferably 45°.Machine head (10) according to one of the preceding claims, characterized in that the tool receiving device (14) is designed to receive the tool (20) in a releasable manner.Machine head (10) according to one of the preceding claims, with the tool (20) in the form of a mandrel, clamped into the tool receiving device (14).Machine head (10) according to claim 7, characterised in that the mandrel (20) is a cylindrical rotationally symmetrical pin which is preferably further preferably gradually tapered in its diameter towards its free end.Rolling device (100) for necking out a pre-hole (44) in a metallic hollow body (40), having: a rotational axis (MA); a machine head receiving device (110) having a machine head receiving space (112); a machine head (10) accommodated in the machine head accommodation space (112), and a drive device (120) with an associated control device (125), which are designed to move the machine head (10) in at least one of the following operating modes: i) in the form of a rotation about the central axis (MA) of the rolling device (100), ii) in the form of an axial displacement along the central axis (MA) of the rolling device (100) and / or iii) for moving the tool accommodation device (14) of the machine head (10) in the form of a radial displacement with respect to the central axis (MA) of the rolling device (100); wherein the rotational axis (MA) of the rolling device (100) preferably coincides with the central axis (M) of the machine head (10); characterized in that the machine head (10) is formed according to one of the preceding claims; in that the machine head receiving space (112) is delimited at least in sections by a conical inner wall (114); in that the preferably conical guide surface (13) at a free end of the tool receiving device (14) is brought to bear against the conical inner wall (114) of the machine head receiving space (112); and in that the mandrel (20) can be deflected in the radial direction (R) in relation to the axis of rotation (MA) of the rolling device (100) according to a relative position between the machine head (10) and the inner wall (114) of the machine head receiving space (112).Rolling device (100) according to Claim 9, characterized in that the control device (125) has a digital computer with a memory into which the computer program product according to Claim 15 can be loaded.Method for necking out a pre-hole (44) in a metallic hollow body (40) by operating a rolling device (100) according to one of Claims 9 or 10, having the following steps: a) installing the machine head (10) in the machine head receiving device (110) of the rolling device (100); b) clamping the tool (20) in the form of the mandrel (20) into the tool receiving device (14) of the machine head (10); c) clamping the metallic hollow body (40) in a fixed manner into a clamping device (50); d) positioning the rolling device (100) in a fixed manner relative to the metallic hollow body (40); e) retracting the mandrel preferably without rotation into the pre-hole (44) in the metallic hollow body (40) by axially displacing the machine head (10) with the mandrel (20) along the central axis (MA) of the rolling device (100) according to the operating mode ii) of the drive device (120) thereof; f) setting the machine head (10) with the clamped mandrel (20) in rotation about its central axis (M) according to the operating mode i) of the drive device (120), whereby the mandrel (20) performs a tumbling movement about the central axis (M); g) displacing the mandrel (20) under the edge of the pre-hole (44) by radially displacing the machine head (10) or its tool receiving device (14) in each case with the mandrel (20) with respect to the central axis (MA) of the drive device (120) according to the operating mode iii) into a removed position (37); and h) pulling out the tumbling mandrel from the pre-hole (44) by axially retracting the machine head (10) while maintaining its removed position, wherein at the same time the edge of the pre-hole (44) is pulled up to form the neck in the form of a flange on the pre-hole.Method according to claim 11, characterised in that, in order to form necked-out portions which are smaller than the diameter of the hollow body, in particular if the latter is of tubular design, according to step e) the mandrel is moved into the pre-hole (44) in a diagonal movement, which is achieved by superimposing the axial displacement of the machine head with a simultaneously occurring radial feed of the mandrel by radially displacing the tool receiving device (14).Method according to claim 11 or 12, characterised in that the radially outward position of the mandrel can be changed during the extraction of the tumbling mandrel from the pre-hole (44) according to method step h).Method according to one of Claims 11 to 13, characterized in that the mandrel rolls on the edge of the pre-hole (44) in the pre-hole (44) during its tumbling movement about the axis of rotation (MA) and the central axis (M).A computer program product directly loadable into the memory of a digital computer and comprising software code portions with which the steps according to the method of any of claims 11 to 14 are carried out when the computer program product is run on the computer.

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