EP3126070A1

EP3126070A1 - Method for shaping an end of a pipe, associated device for performing the method, rolling element, and a flange shaped therewith at an end of a pipe

Info

Publication number: EP3126070A1
Application number: EP15741900.3A
Authority: EP
Inventors: Manfred Klever
Original assignee: Efs Euro Forming Service GmbH
Current assignee: Efs Euro Forming Service GmbH
Priority date: 2014-04-03
Filing date: 2015-04-01
Publication date: 2017-02-08
Also published as: WO2015172940A1; DE102014104775A1; US20170021401A1

Abstract

The invention relates to a method for shaping an end of a pipe (R, R'), preferably a hollow shaft suitable for use in a vehicle, in particular a hollow axle shaft. A rolling element (W, W, W") rotates about its longitudinal axis at a first rotational speed and substantially has a conical or cone-frustum-shaped form. The rolling element (W, W, W") has a rotationally symmetric rolling surface (WF, WF', WF") around its longitudinal axis (LW, LW', LW"), wherein the contour of the rolling surface (WF, WF', WF") is curved inward at least in some sections. The pipe (R, R') rotates about its longitudinal axis (LW, LW', LW") at a second rotational speed. The rolling element (W, W', W") and the pipe (R, R') rotate in the same direction of rotation. The longitudinal axis (LW, LW', LW") of the rolling element is arranged parallel to the longitudinal axis of the pipe (R, R'). The longitudinal axis (LW, LW', LW") of the rolling element is arranged eccentrically to the longitudinal axis (LR, LR') of the pipe at a predetermined normal distance (a). The rolling element (W, W', W") and the pipe (R, R') are brought in contact in such a way that the rolling surface (WF, WF', WF") of the rolling element contacts the pipe (R, R') in the region of the end of the pipe (R, R') at a contact surface (KF) located on an inner pipe wall. The first rotational speed (D1) and the second rotational speed (D2) are set in such a way that the magnitude of the difference calculated from a circumferential speed (U1) of the rolling element (W, W', W") minus a circumferential speed (U2) of the pipe (R, R') at the contact surface (KF) is in the range of 0 to 10%, preferably 0 to 5%, especially preferably 0 to 2%, with respect to the circumferential speed (U1) of the rolling element (W, W', W"). By means of a relative motion between the rolling element (W, W', W") and the pipe (R, R'), the rolling element (W, W', W") transmits a force to the inner pipe wall of the pipe (R, R') in the region of the contact surface (KF) in such a way that the end of the pipe (R, R') is shaped radially outward.

Description

description

A method of forming an end of a pipe, apparatus for carrying out the method, rolling elements and a molded therewith

Flange at one end of a pipe

The invention relates to a method for forming an end of a tube, preferably a suitable for use in a vehicle hollow shaft, in particular a hollow shaft, a device for carrying out the method associated with a rolling body and a thus formed at one end of a pipe flange.

For transmitting the driving force from an internal combustion engine as the drive unit of a vehicle to the drive wheels, shafts are commonly used, e.g. a cardan shaft or axle shaft. Conventional axle shafts of a commercial vehicle consist of a solid material, so that the axle shaft is a solid shaft. One end of the axle shaft is connected to the differential and at an opposite other end are various components, such as wheel, brake device, wheel bearing and the corresponding drive wheel attached. So that the drive wheel can be fastened to the other end, a flange is provided by upsetting.

In view of the strict emission limit values prescribed by various authorities and commissions, such as the Euro 6 emission standard, the weight savings of the individual components integrated in the vehicle contribute significantly to fulfilling these requirements and set targets. Accordingly, attempts have been made to design such axle shafts as hollow shafts, since the bending load in the interior of the axle shaft is lower in comparison to the outside and thus the core of a solid shaft contributes less to the stability. An axle hollow shaft is offered, for example, by the US Manufacturing Cooperation (USM). However, in this axle hollow shaft, the flange required for the brake device and the drive wheel is welded to the axle hollow shaft. However, the provision of a connecting weld on a shaft used in the drive train for transmitting the power flow from the internal combustion engine to the drive wheels involves numerous problems, such as inclusions, pore and blistering in the weld, insufficient penetration, etc., with it. Despite different testing methods for welds, these problems, errors or quality differences of the welds can occur in practice. Therefore, the weld at high loads, such as is present in the transmission of the driving force from the internal combustion engine to the drive wheels, undesirable tear.

From US 8,291,737 a printing device for bending an end of a metallic tube for air conditioning, refrigeration, plumbing and heating technology is disclosed. In this case, a mandrel is driven via a central shaft. The mandrel strikes obliquely on the edge-side inner wall of the pipe end, so that only a portion of the pipe end is machined in the circumferential direction. However, this printing device is a mobile device that can only be used to machine pipes with a small wall thickness, as is customary in the field of air conditioning, refrigeration, sanitary and heating technology.

US 3,192,758 teaches an expansion device for forming openings in a metal tube. By a coaxial relative movement between the tube and the mandrel, a widening of the pipe end is carried out. However, it has turned out to be disadvantageous that, when the mandrel and the tube make a relative movement relative to one another, the surface of the mandrel rests completely in the region of the end of the tube. To widen the tube, the expansion device therefore requires a powerful feed drive, since the entire circumference of the pipe end is widened.

The US 3,494,162 describes an apparatus for forming an end portion of a can, whereby at the end of a flange is formed. The end of Can is attached to its processing by means of a holder on a base. For processing the can end several processing heads are disclosed. One of the processing heads has three inwardly curved rollers which deform the can end outwardly to form a flange. To expand the can, the expander requires a powerful feed drive, since the entire circumference of the can end is widened.

From US 6,016,678 a method for expanding and forming a flange on a boiler tube is known. The method is directed to the connection of boiler tubes with a tubesheet for use in steam boilers. For this purpose, a device is used in which a plurality of Aufweitwalzen held in a cage and is driven radially by a rotating mandrel. As a result, the diameter of the tube is radially increased in a coaxial relative movement between the tube and the expansion device. Furthermore, the expansion device has a likewise radially driven by a mandrel forming roll, which is adapted such that at the pipe end a bent-back flange is formed. The flange serves to firmly connect the tube to the tubesheet. The device has a complex structure and due to the radially rolling rollers and associated higher friction less economical.

However, the prior art discloses neither a method nor a suitable apparatus for forming a flange for a pipe, in particular for a driving force of an internal combustion engine transmitting hollow shaft. Accordingly, it is the object of the present invention to provide a method for producing a non-welded flange at one end of a tube, wherein the outer diameter of the flange is at least 1.5 times the outer diameter of the end of the tube before the forming and the flange a small forming force is formed. This object is achieved by a method for forming an end of a tube, preferably a suitable for use in a vehicle hollow shaft, in particular an axle hollow shaft, having the features of claim 1.

According to the invention, a method is proposed for forming an end of a pipe, preferably a hollow shaft suitable for use in a vehicle, in particular an axle hollow shaft. In this case, a rolling body rotates about its longitudinal axis at a first speed and has a substantially conical or frusto-conical shape. The rolling body has about its longitudinal axis on a rotationally symmetric rolling surface, wherein the contour of the rolling surface is at least partially curved inward. The tube rotates about its longitudinal axis at a second speed. The rolling element and the tube rotate in the same direction of rotation. The longitudinal axis of the rolling element is arranged parallel to the longitudinal axis of the tube. The longitudinal axis of the rolling body is arranged eccentrically to the longitudinal axis of the tube by a predetermined normal distance. The rolling body and the tube are brought into contact such that the rolling surface of the rolling body touches the tube in the region of the end of the tube at a contact surface located on an inner tube wall. The first rotational speed and the second rotational speed are set so that the amount of the difference calculated from a peripheral speed of the rolling body minus a peripheral speed of the tube at the contact surface based on the peripheral speed of the rolling body is in the range of 0 to 10%, preferably 0 to 5%, more preferably from 0 to 2%. By a relative movement between the rolling body and the tube, the rolling body transmits a force to the inner tube wall of the tube in the region of the contact surface such that the end of the tube is deformed radially outward.

In the context of the invention, the contour of the rolling surface curved inwards at least in sections means that the contour is, for example, curved inward or arched, virtually convex. The contour is continuous or not continuous formable. The contour may include, in addition to one or more inwardly curved portions, one or more rectilinear portions which together provide the inwardly curved rolling surface. The rectilinear sections can be one have different pitch and the inwardly curved portions may have a different curvature. For the purposes of this invention, "rolling surface" of the rolling body is to be understood as meaning the surface which comes into contact with the inner wall of the end of the tube during the forming.

For the purposes of this application, "roller body with a conical or frustoconical shape" is understood to mean a rolling body having a basic shape of a rotationally symmetric cone or a rotationally symmetrical truncated cone deviate from the linear shape, that is, arched inwards or outwards, or be designed in sections linear or curved, wherein the individual sections may have different slopes or bulges in a piecemeal In the design of the contour or surface line, the transitions between the individual sections may each be continuous or unsteady The deviation from the ideal basic shape of the cone or truncated cone described above is defined in particular by the term "substantially conical or frusto-conical shape ", but is also encompassed by the term" conical or frusto-conical shape ".

According to the invention, the term "rolling element with a conical or frustoconical shape" or "rolling element with a substantially conical or frustoconical shape" also includes rolling elements having the above-described configuration, which have a circumferential collar in the region of their radial end section or on the outer circumference. In this case, the contour of the rolling body is continuous radially or seamlessly into the contour of the federal. The collar preferably has a draft on its inside. By "working surface" is meant the full surface of the inner wall of the end of the tube that has been or has been reshaped by the rolling surface of the rolling element Touch the wall of the end of the pipe during forming. The contact area changes depending on the progress of the forming process and is thus a function of time. Upon contact of the rolling surface with the end of the tube at the beginning of forming, the inner tube wall also includes the inner edge of the tube.

The required relative to the deformation relative movement between the rolling body and tube can be achieved by a) the rolling body on the tube or b) the tube is moved to the rolling body or c) the tube and the rolling body are moved toward each other together.

Due to the eccentric arrangement of the longitudinal axis of the rolling body to the longitudinal axis of the tube, the rolling surface is not fully against the inner wall of the end of the tube. Consequently, the contact surface does not extend over the entire circumference of the processing surface. As a result, the pressure transferable to the contact surface and producible for deformation is greater than full contact of the rolling surface against the inner wall of the end of the tube while the drive force is kept constant. As a result, either tubes with greater wall thickness or outer diameter can be formed, or a device with smaller dimensions, lower power consumption and low torque can be used. The power requirement of the device is thus only a fraction, namely about 10%, compared to conventional expansion devices, in particular to the expansion device disclosed in the above-described US 3,192,758. The inventive design of the rolling body, in particular the at least partially inwardly curved contour of the rolling surface, allows advantageous Way that during the deformation of the material of the end of the tube along the contour of the rolling surface flows radially outward.

Due to the fact that the tube and the rolling body rotate in the same direction at essentially the same circumferential speeds, smearing of the rolling body from the tube, namely at the contact surface, or vice versa, is effectively avoided. Thus, unnecessary friction is avoided and the pipe is not damaged on the inner pipe wall. With this method, for the first time, a flange can be produced on a pipe, preferably a hollow shaft suitable for use in a vehicle, in particular an axle hollow shaft, without providing welds, the flange having dimensions such as to secure a drive wheel thereto. The hollow shaft suitable for use in a vehicle may be a propeller shaft, an axle shaft, a side shaft, a connecting shaft, a shaft used in the steering unit or compressors, and so on.

Further embodiments of the method according to the invention are the subject of the dependent claims.

The force transmitted to the inner wall of the tube may be at most 500 kN (50 t), preferably in a range between 1 (0.1 t) and 400 kN (40 t), preferably in a range between 5 (0.5 t ) and 300 kN (30 t), more preferably in a range between 10 (1 t) and 250 kN (25 t). Since due to the eccentricity of the longitudinal axis of the rolling body to the longitudinal axis of the tube, the rolling surface rests only on the contact surface on the inner wall of the end of the tube, only a fraction of the force is required for the forming, whereby the method is particularly suitable for relatively small production machines. In a projection of the contact surface and a projection of the rolling surface on a plane perpendicular to the longitudinal axis of the rolling body, the projection of the contact surface in a circular section of the projection of the rolling surface can be completely contained be. The circular section may have a center angle of at most 240 °, preferably at most 180 °, preferably at most 150 °, particularly preferably at most 120 °. The circular section may have a midpoint angle of at most 210 °, preferably at most 170 °, preferably at most 130 °, particularly preferably at most 105 °. The smaller the contact area is set, the smaller the center angle and the higher the pressure acting on the contact surface.

The material of the end of the tube is supportable from a first concern on an inner side of a collar circulating on an outer circumference of the rolling body for the duration of a period during the forming on the inside of the collar. With this design can be effectively avoided that the material terminates at a shaped end of the tube pointed. In particular, it is desirable for a subsequent pressure forming process that the flange formed by the forming has a constant wall thickness, or even has a wall thickness greater than the original wall thickness at an edge portion of the formed tube.

The first rotational speed of the rolling body may be between 300 and 1500 rpm, preferably between 450 and 1100 rpm, particularly preferably between 600 and 700 rpm. The second rotational speed of the tube may be between 300 and 1500 rpm, preferably between 450 and 1100 rpm, particularly preferably between 600 and 700 rpm. Especially in these speed ranges, the method for forming an end of the tube is advantageously carried out.

The end of the tube may, at least while the rolling body is in contact with an inner wall of the end of the tube, have a temperature between 700 to 1300 ° C, preferably between 1000 to 1250 ° C, more preferably between 150 to 1200 ° C , The rolling element, at least while it is in contact with an inner wall of the end of the tube, a temperature between 100 to 250 ° C, preferably between 140 to 210 ° C, more preferably between 150 to 200 ° C. The rolling body and / or the end of the tube are for example Inductively heated. In these temperature ranges of the tube and the rolling body, the method of uniforming one end of the tube is advantageously carried out.

In addition to a conventionally produced tube with a uniform outside diameter and / or with a uniform wall thickness, in the method as well a tube which has been puffed up in a hot manner before the deformation carried out with the rolling body can also be used.

After the forming by means of the rolling body, the flared end of the tube is further deformable by at least one pressure forming process. Pressure forming processes are for example compression molding, drop forging, cold sinking, upsetting, etc.

According to a further aspect of the invention, a flange is proposed according to claim 1 1. The flange according to the invention is produced at one end of a pipe, preferably a hollow shaft suitable for use in a vehicle, in particular an axle hollow shaft, according to the method described above. For the first time, it is possible with this method to form a flange on a pipe, preferably a suitable for use in a vehicle hollow shaft, in particular an axle hollow shaft, without providing welds, wherein on the flange, for example, a drive wheel is mounted on different assemblies.

An outer diameter of the deformed end of the tube may have a ratio of greater than 1.5: 1, preferably greater than 2: 1, preferably greater than 3: 1, particularly preferably greater than 4: 1, to an outer diameter of an unconverted section of the tube. An outer diameter of the deformed end of the tube may have an outer diameter of an unconverted section of the tube, but also a ratio of greater than 1, 5: 1, preferably greater than 1, 8: 1, preferably greater than 2.5: 1, particularly preferably greater 3.5: 1, have. For such a ratio to be achieved, the rolling surface must have a corresponding dimension in the radial direction. The deformed end of the tube may have at least a portion having a wall thickness that is greater than a wall thickness of an un-deformed portion of the tube. Such formation of the flange is particularly important in a subsequent pressure forming process to perform a subsequent pressure forming process for shaping the final flange contour.

According to a further aspect of the invention, an apparatus for reshaping an end of a pipe, preferably a hollow shaft suitable for use in a vehicle, in particular an axle hollow shaft, is preferably proposed for carrying out the method described above. The device has a rolling body with a longitudinal axis. The rolling body essentially has a conical or frustoconical shape and has a rotationally symmetrical rolling surface about its longitudinal axis, wherein the contour of the rolling surface is arched inwards at least in sections. Furthermore, the device has a rotatable device for receiving and fixing the tube. The longitudinal axis of the rolling body is eccentrically spaced by a predetermined normal distance and parallel to a longitudinal axis of the tube when the tube is attached to the device. Here, the same effects according to the invention of the method described above are achieved.

The ratio of the normal distance to an outer diameter of the end of the tube before forming may be in a range from 1:60 to 1: 2, preferably from 1:30 to 1: 3, more preferably from 1: 6 to 1: 3 , In the case of a tube with an outer diameter of 60 mm, the normal distance may be between 1 and 40 mm, preferably between 5 and 30 mm, particularly preferably between 10 and 20 mm.

The rolling body is axially, preferably by means of a drive shaft, driven about its longitudinal axis. The rolling body can be driven by means of its shaft during axial driving or by being mounted on a drive shaft of a device for transforming one end of the tube. According to a further aspect of the invention according to claim 17, a rolling body for forming an end of a tube, preferably a suitable for use in a vehicle hollow shaft, in particular an axis hollow shaft, preferably suitable for carrying out the method described above, proposed. The rolling body has a substantially conical or frusto-conical shape and about its longitudinal axis on a rotationally symmetrical rolling surface. The contour of the rolling surface is at least partially curved inwards. On an outer periphery of the rolling body, a circumferential collar is arranged. The inwardly curved or curved, quasi-convex contour of the rolling surface merges seamlessly radially outward into the collar. The collar preferably has an Entformungsschräge of greater than 0 °, preferably greater than 1 °, more preferably greater than 5 ° on. The collar can be formed integrally with the rolling body or can be arranged in another way, such as by welding, to the rolling body. With the rolling body according to the invention, the same effects according to the invention of the method described above are obtained.

A tangent applied to a radially outer edge portion of the rolling surface may include an angle of greater than 70 to 105 °, preferably greater than 75 to 100 °, more preferably greater than 80 to 95 ° with the longitudinal axis. When viewed from a point or a flattening in the direction of a base, it is that angle between the longitudinal axis and the tangent that is spanned away from the tip. The material of the end of the tube flows accordingly along the contour of the rolling surface radially advantageous according to the above angle information to the outside, so that a subsequent pressure forming process for shaping the final flange contour is feasible.

According to a further aspect of the invention, a rolling body is proposed for forming an end of a pipe, preferably a hollow shaft suitable for use in a vehicle, in particular an axle hollow shaft, preferably suitable for carrying out the method described above. The rolling body has a rolling surface and a longitudinal axis, wherein an applied at any point of the rolling surface tangent to the longitudinal axis at an angle of greater 0 to 120 °, preferably from greater than 0 to 105 °, particularly preferably of greater than 0 ° to 90 °, including, in a portion of the roll surface of the angle greater than 45 °, preferably greater than 60 °, particularly preferably 70 ⁰ or more, is wherein the portion comprises an edge region of the rolling surface, and wherein the angle increases at least in sections as the normal distance of the point from the longitudinal axis increases. When viewed from a point or a flattening in the direction of a base, it is that angle between the longitudinal axis and the tangent that is spanned away from the tip. According to yet another aspect of the invention, a rolling body for

Forming an end of a pipe, preferably a suitable for use in a vehicle hollow shaft, in particular a hollow shaft axis, preferably suitable for carrying out the method described above, proposed. The rolling body has a longitudinal axis and a rolling surface with a contour, wherein the contour of the rolling surface is formed such that during a deformation of a tube wall of one end of the tube in a range between 70 ° and 120 ⁰ to the longitudinal axis of the rolling body radially outwardly deformable ,

The above-described features and functions of the present invention as well as other aspects and features will be further described below with reference to a detailed description of preferred embodiments with reference to the accompanying drawings. Hereby shows / show:

Figs. 1a to 1c are sectional views of rolling bodies according to the invention;

Fig. 2 is a sectional view of a device according to the invention for forming an end of a pipe;

Figs. FIGS. 3 to 5 are cross-sectional views illustrating different timings of a method of the apparatus for forming an end of a pipe; Figs. 6 and 7 projections of a contact surface and a rolling surface on a plane; and

Figs. 8 and 9 show an apparatus for carrying out a pressure forming process with a punch and a die.

1a shows a sectional view of a rolling body W according to the invention in accordance with an embodiment of a rolling body. The rolling body W is rotationally symmetrical about its longitudinal axis LW with a rolling surface WF serving for forming, more precisely rolling, a workpiece. The rolling surface WF is curved inward and extends from a lying on the longitudinal axis LW spike-like point S inwardly curved radially outward. A tangent T applied to an arbitrary point P of the rolling surface WF shown in FIG. 1 includes an angle α with the longitudinal axis LW. Due to the inwardly curved formation of the rolling surface LW, the angle α of the mandrel-like tip S increases radially outward, so that any points P of the rolling surface WF include an angle α of greater than 0 ⁰ to about 85 °. When viewing from a point S in the direction of a base BA, it is the angle α between the longitudinal axis LW and tangent, which is spanned from the tip S facing away. At an edge portion of the rolling surface WF, where the point P has the largest angle α, a collar B circulating on an outer circumference of the rolling body W is provided. The collar B is formed integrally with the rolling body W and has an inner side I with a Entformungsschräge ß of 5 °. The rolling body W has a shaft, not shown, for receiving in a device.

1 b shows a sectional view of a further rolling body W 'according to the invention. The rolling body W' with a longitudinal axis LW 'has a different rolling surface WF' in comparison to the rolling body W according to FIG. The rolling surface WF 'has three sections Ai, A ₂ , A3 with different pitch, in which the tangents T with the longitudinal axis LW' applied at arbitrary points P in each section Ai, A ₂ , A3 of the rolling surface WF 'have the same angle α have. The angle α of the tan applied at the points P in the section Ai of the rolling surface WF ' The angle α of the tangents applied at the points P in the section A _{2 of} the rolling surface WF 'is 70 ° and the angle α of the tangents applied at the points P in the section A _{3 of} the rolling surface WF' is 90 °. When viewed from a point S 'in the direction of a base BA', it is the angle α between the longitudinal axis LW 'and tangent, which is spanned from the tip S' facing away.

FIG. 1c shows a sectional illustration of a further rolling body W "according to the invention. The rolling body W" with a longitudinal axis LW "has no thorn-like point S in comparison to the rolling body W according to FIG. 1a, but a flat AB, so that the rolling body The flattening AB is not used to reshape an end of a pipe and does not form part of the rolling surface WF ". A transition between flattening AB to the rolling surface WF" is designed so that the angle α of a tangent at a point P When looking from a flattening AB in the direction of a base BA ", it is the angle α between the longitudinal axis LW" and the tangent that is spanned away from the flattening AB.

Fig. 2 shows a sectional view of a device according to the invention for forming an end of a pipe R according to an embodiment of such a device. In the apparatus for forming an end of a pipe R, the rolling body W according to the invention as shown in FIG. La is used.

The roller body W fastened to a drive shaft via a shaft Z is driven in rotation by a first drive motor, not shown, at a first rotational speed Di. The drive shaft is movable and adjustable together with the rolling body W by means of a feed motor, not shown, in the axial direction and for accurate positioning transversely to the axial direction via a carriage system consisting of a plurality of carriages. The pipe R is mounted in a rotatable means H for receiving and fixing the pipe R. The tube R fastened in the device H is rotationally driven at a second rotational speed D ₂ by a further drive motor (not shown ₎ . exaggerated. For accurate positioning transverse to the axial direction, the rotatable device H also includes a not shown carriage system consisting of a plurality of carriages. In Fig. 2, the rolling body W with its longitudinal axis LW and the tube R are arranged with its longitudinal axis LR parallel and eccentric with a normal distance a to each other.

FIGS. 3 to 5 are sectional views showing different time points or instantaneous images of a method according to the invention for forming an end of a warmly upset pipe R '. The hot upset pipe R 'consisting of steel has an outer diameter of 115 mm and a wall thickness 1 of 18 mm. The normal distance a between the longitudinal axis LW of the rolling body W and the longitudinal axis LR of the warm upset tube R 'is 15 mm. The first speed D] of the rolling body W and the second speed D _{2 of} the warm upset tube R 'are set at 600 rpm during the entire forming, so that a peripheral speed Ui of the rolling body W and a peripheral speed U _{2 of} the warm upset tube R' are the same. For forming the warm upset pipe R 'is heated to 1150 ° C and the rolling body W to 150 ° C inductively.

The warm upset tube R 'with a first speed Όι is moved to the rolling surface WF of the rolling body W at a second speed D ₂ in the axial direction. At the beginning of the deformation by means of the rolling body W, the end of the hot upset tube R 'and the rolling surface WF touch each other at an inner edge IN of the end of the warm upset tube R', so that a contact surface KF in three-dimensional view touches a circumferential surface is a line running in two-dimensional view, as shown in Fig. 3, is a point. With continuous movement of the warm upset tube R 'in axial

Direction to the rolling surface WF of the rolling body W, as shown in Fig. 4, the material of the end of the tube R 'along the contour of the rolling surface WF continuous borrowed radially outward, ie, the material flows radially outward. As a result, the contact surface KF, in which the rolling surface WF of the rolling body W is in contact with a currently in contact processing surface BF of an inner tube wall RI of the hot upset tube R ', is enlarged and viewed three-dimensionally as an area and in two-dimensional viewing, as shown in Fig. 4, to recognize as a line. The machining surface BF forms the entire surface machined during the forming, namely an inside of the hot upset pipe R \ expanded in FIG. 4. At the end of the forming by means of the rolling body W, as shown in FIG. 5, the contact surface KF is largest. Already shortly before, the end of the warmly accumulated pipe R 'abuts the inside I of the collar B circulating on the outer circumference of the rolling body W, so that a thickening of the end of the pipe R' is formed. The deformed end has near its end face a greater wall thickness H than a wall thickness l _{2 of} an unconverted region of the warm upset tube R 'and / or a deformed region of the tube R' lying further in the center of the hot upset tube R '. on. The Entformungsschräge ß allows the separation of the warm dammed pipe R 'from the rolling body W in the opposite, axial direction or vice versa.

FIGS. 6 and 7 show projections of the contact surface KF and the rolling surface WF on a plane lying in the plane of the drawing at different time points of the forming. A hatched projection PK of the contact surface KF and a projection PW of the rolling surface WF are on a longitudinal axis LW represented vertical plane, wherein the projection PK of the contact surface KF is completely contained in a circular section of the projection PW of the rolling surface WF. In FIG. 6, the circular section has a center point angle φ of 65 ° and in FIG. 7 the circular section has a center angle φ of 120 °. The projection PK of the contact surface KF shown in FIG. 6 corresponds approximately to the contact surface KF shown in FIG. The projection PK of the contact surface KF shown in FIG. 7 corresponds approximately to the contact surface KF shown in FIG. Since the hatched projection PK of the contact surface KF occupies only a circular section of the projection PW of the rolling surface WF, ie does not extend around the entire circumference of the hot upset tube R ', less feed force (maximum 250 kN or approx t) for the deformation of the end of the warm upset pipe R 'needed. The rolling body W also brings at constant over the entire deformation set feed force the largest pressure at the beginning of the forming on the end of the hot upset tube R ', since at this time, the contact surface KF is smallest. Figures 8 and 9 illustrate a device for carrying out a pressure forming process with a punch S and a die M. The end of the warm upset tube R 'is introduced as a blank in the die M and obtained by interaction of die M and punch S its final Form, so that a flange on a warm upset pipe R 'is formed.

The invention allows not only the illustrated embodiments but also further design approaches.

The rolling body W 'has three sections with different pitch. However, the rolling surface of a rolling body according to the invention is also designed to have one, two, four, five or any number of rectilinear sections and / or one, two, three or any number of inwardly curved sections. The rolling elements described above have a shaft, not shown, for receiving in a device; However, the rolling elements can also be designed as Aufsteckwerkzeuge.

In the apparatus for forming one end of a pipe R, the rolling body is not limited to the rolling body W shown in FIGS. 2 to 5, but it is the use of other rolling bodies, such as the rolling body W 'of FIG. 1b, of the rolling body W "according to FIG. Lc etc. possible. Although a hot upset tube R 'with a wall thickness 1 of 18 mm is deformed in advance, it is also possible according to the invention to transform tubes having a wall thickness between 5 mm to 100 mm, preferably between 10 mm and 80 mm, particularly preferably between 15 mm and 70 mm mm, have.

Although the processed in the execution form warm upset pipe R 'is made of steel, pipes made of aluminum or an alloy of steel and / or aluminum can be converted according to the invention.

Although not shown in Figs. 8 and 9, openings may still be made in the flange on the warm upset tube R ', e.g. Holes, tapped holes, etc., are provided.

Claims

claims

1. A method for forming an end of a tube (R, R ') ₅ preferably a suitable for use in a vehicle hollow shaft, in particular an axis hollow shaft, wherein a rolling body (W, W', W ") about its longitudinal axis (LW, LW ' , LW ") at a first rotational speed (Di), wherein the rolling body (W, W ', W") has a substantially conical or frusto-conical shape, wherein the rolling body (W, W', W ") about its longitudinal axis (LW, LW ', LW ") has a rotationally symmetrical rolling surface (WF, WF \ WF"), and wherein the contour of the rolling surface (WF, WF', WF ") is at least partially curved inward, the tube (R, R ') rotates about its longitudinal axis (LR, LR') at a second rotational speed (D ₂ ), the rolling bodies (W, W ', W ") and the tube (R, R') rotate in the same direction, the longitudinal axis (FIG. LW, LW ', LW ") of the rolling body (W, W \ W") is arranged parallel to the longitudinal axis (LR, LR') of the tube (R, R '), the longitudinal axis (LW, LW ', LW ") of the rolling body (W, W', W") to the

Longitudinal axis (LR, LR ') of the tube (R, R') by a predetermined normal distance (a) is arranged eccentrically, the rolling body (W, W ', W ") and the tube (R, R') brought into contact be that the rolling surface (WF, WF ', WF ") of the rolling body (W, W \ W"), the tube (R, R') in the region of the end of the tube (R, R ') at one on an inner tube wall contacting the contact surface (KF), wherein the first rotational speed (D]) and the second rotational speed (D ₂ ) are set such that the amount of the difference calculated from a peripheral speed (L) of the rolling body (W, W ', W ") minus a peripheral speed (U ₂ ) of the pipe (R, R ') at the contact surface (KF), relative to the peripheral speed (Ui) of the rolling body (W, W', W "), in the range of 0 to 10% from 0 to 5%, more preferably from 0 to 2%, and wherein by a relative movement between the rolling body (W, W ', W ") and the tube (R, R') of the rolling bodies (W, W ', W ") a force on the inner ro Transverse wall of the tube (R, R ') in the region of the contact surface (KF) transmits such that the end of the tube (R, R') is deformed radially outward.

A method according to claim 1, characterized in that the force is at most 500 kN (50t), preferably in a range between 1 and 400 kN, preferably in a range between 5 and 300 kN, more preferably in a range between 10 and 250 kN ,

A method according to claim 1 or 2, characterized in that in the case of a projection (PK) of the contact surface (KF) and a projection (PW) of the rolling surface (WF, WF ', WF ") onto the longitudinal axis (LW, LW', LW") of the rolling body (W, W \ W ") vertical plane, the projection (PK) of the contact surface (KF) in a circular section of the projection (PW) of the rolling surface (WF, WF ', WF ") is completely contained, and wherein the circular section has a center angle (φ) of at most 240 °, preferably at most 180 °, preferably at most 150 °, particularly preferably at most 120 °.

Method according to one of claims 1 to 3, characterized in that the material of the end of the tube (R, R ') from a first concern on an inner side (I) of an outer periphery of the rolling body (W, W', W ") circulating collar (B) for the duration of a period during the forming on the inside (I) of the collar (B) is supported.

Method according to one of claims 1 to 4, characterized in that the first speed (Di) of the rolling body (W, W \ W ") between 300 to 1 00 U / min, preferably between 450 to 1 100 U / min, particularly preferred between 600 to 700 rpm.

Method according to one of claims 1 to 5, characterized in that the second speed (D ₂ ) of the tube (R, R ') between 300 to 1500 U / min, preferably between 450 to 1 100 U / min, more preferably between 600 up to 700 rpm. Method according to one of claims 1 to 6, characterized in that at least during the rolling bodies (W, W ', W ") is in contact with an inner wall of the end of the tube (R, R'), the end of the tube (R , R ') has a temperature between 700 to 1300 ° C, preferably between 1000 to 1250 ° C, more preferably between 1 150 to 1200 ° C, having.

Method according to one of claims 1 to 7, characterized in that at least during the rolling bodies (W, W ', W ") is in contact with an inner wall of the end of the tube (R, R'), the rolling body (W, W \ W ") has a temperature between 100 to 250 ° C, preferably between 140 to 210 ° C, more preferably between 150 to 200 ° C.

Method according to one of claims 1 to 8, characterized in that the tube (R, R ') is hot-upset before it is formed by means of the rolling body (W, W', W ").

Method according to one of claims 1 to 9, characterized in that after the deformation by means of the rolling body (W, W ', W "), the flared end of the tube (R, R') is further formed by means of at least one pressure forming process.

11. Flange at one end of a tube (R, R '), preferably a suitable for use in a vehicle hollow shaft, in particular an axis hollow shaft, produced by the method according to one of claims 1 to 10.

12. A flange according to claim 11, characterized in that an outer diameter (di) of the deformed end of the tube (R, R ') to an outer diameter (d ₂ ) of an unformed portion of the tube (R, R') has a ratio (di / d ₂ ) of greater than 1, 5: 1, preferably greater than 2: 1, preferably greater than 3: 1, particularly preferably greater than 4: 1.

Flange according to claim 1 1 or 12, characterized in that the deformed end of the tube (R, R ') has at least one section with a wall thickness (12) which is greater than a wall thickness (1 ₂ ) of an unconverted section of the wall Tube (R, R ').

14. An apparatus for forming an end of a pipe (R, R '), preferably a suitable for use in a vehicle hollow shaft, in particular an axis hollow shaft, preferably suitable for carrying out the method according to one of claims 1 to 10, wherein the device comprises: a Rolling body (W, W \ W ") having a longitudinal axis (LW, LW ', LW"), wherein the rolling body (W, W', W ") has a substantially conical or frusto-conical shape, wherein the rolling body (W, W ', W ") has a rotationally symmetrical rolling surface (WF, WF', WF") about its longitudinal axis (LW, LW ', LW "), and wherein the contour of the rolling surface (WF, WF', WF ") at least partially inwardly curved, a rotatable means (H) for receiving and fixing the tube (R, m wherein the longitudinal axis (LW, LW ', LW") of the rolling body (W, W', W ") to a predetermined normal distance (a) is arranged eccentrically and parallel to a longitudinal axis (LR, LR ') of the tube (R, R') when the tube (R, R ') is attached to the device (H).

15. The apparatus according to claim 14, characterized in that the ratio of the normal distance (a) to an outer diameter of the end of the tube (R, R ') before forming in a range of 1: 60 to 1: 2, preferably from 1 : 30 to 1: 3, more preferably from 1: 6 to 1: 3.

16. The apparatus of claim 14 or 15, characterized in that the rolling body (W, W ', W ") axially, preferably by means of a drive shaft (A), about its longitudinal axis (LW, LW', LW") is drivable.

17. rolling body (W, W ', W') for forming one end of a tube (R, R '), preferably a hollow shaft suitable for use in a vehicle, in particular an axle hollow shaft, preferably suitable for carrying out the method according to one of claims 1 to 10, wherein the rolling body (W, W ', W ") has a substantially conical or frusto-conical shape, wherein the rolling body (W, W', W ") has a rotationally symmetrical rolling surface (WF, WF ', WF") about its longitudinal axis (LW, LW', LW "), and wherein the contour of the rolling surface (WF, WF ', WF") is curved inwardly at least in sections, wherein on an outer circumference of the rolling body (W, W ', W ") a circumferential collar (B) is arranged, and preferably the collar (B) a draft angle (ß) of greater than 0 °, preferably greater than 1 °, more preferably greater than 5 °, has.

Rolling element according to Claim 17, characterized in that a tangent (T), which is applied to a radially outer edge section of the rolling surface (WF, WF ', WF "), has an angle (a) of greater than 70 to 105 °, preferably greater than 75 to 100 °, particularly preferably greater than 80 to 95 °.