EP3670018A1 - Method and reforming assembly for producing a drum-shaped gearing part - Google Patents

Abstract

The invention relates to a method and a forming system for producing a gear part (10) by rotary forming. According to the invention, a rotationally symmetrical workpiece (5) is set in rotation about its central axis (12) in a preforming step, and an ironing press roll is carried out by at least axial infeed and overflow of at least one forming roller, a cylindrical peripheral wall (14) with a defined target wall thickness is formed, which is less than an initial wall thickness of the workpiece (5). Subsequently, in a final shaping step, the preformed workpiece is clamped on an internal mandrel with external toothing and set in rotation and at least one profiled toothing roller is fed radially, through which the cylindrical peripheral wall is essentially molded into the external toothing of the internal mandrel while maintaining the target wall thickness, a drum-shaped toothing area ( 16) is formed with a folding toothing (20).

Description

The invention relates to a method for producing a drum-shaped gear part by rotary forming, according to the preamble of claim 1.

The invention further relates to a forming system according to claim 9, which is designed in particular to carry out a method for producing a drum-shaped gear part.

Several manufacturing methods for drum-shaped gear parts, in particular clutch plate carriers, are known from the prior art. Depending on the type of toothing that can be used, the number of pieces and the size of the clutch plate carrier, axial rolling is essentially provided on a press for large numbers of pieces. In the case of smaller quantities, incremental forming processes are used, depending on the torques to be transmitted or the component requirements, in particular spinning, profiling or axial rolling in partial steps.

The requirements for NOx reduction and CO ₂ saving in vehicle construction require an increasing weight reduction in the transmissions and the transmission components, including the clutch disc carriers. Here, the material requirements also change to higher-strength materials.

However, ever increasing demands on the finished part push the existing machining processes to their limits and usually require additional forming steps or post-processing steps.

The so-called folding toothing has long been known for the production of clutch plate carriers. In this method, a usually cup-shaped deep-drawn part is placed on a profiling machine between a tool mandrel and a pressure disc and set in rotation. The tool mandrel has the negative shape of the component toothing to be produced. A toothing roller with a corresponding toothing profile is then fed to the workpiece, so that the toothing profile on the inside and the outside is formed into the tool between the tool mandrel and the toothing roller, so that a fold-like toothing is created.

The invention has for its object to provide a method and a forming system with which gear parts can be efficiently manufactured with a particularly flexible and requirement-oriented component design.

The object is achieved on the one hand by a method with the features of claim 1 and on the other hand by a forming system with the features of claim 9. Preferred embodiments of the invention are specified in the respective dependent claims.

The method according to the invention is characterized in that, in a preforming step, a rotationally symmetrical workpiece is set in rotation about its central axis and an ironing-pressing roll is carried out by at least axially advancing and overrunning at least one shaping roller, a cylindrical peripheral wall having a defined target wall thickness which is less than is an initial wall thickness of the workpiece, and that, in a final shaping step, the preformed workpiece is then clamped on an internal mandrel with external toothing and set in rotation, and at least one profiled toothing roller is fed radially, by means of which the cylindrical peripheral wall is essentially retained in the external toothing of the internal mandrel while maintaining the target wall thickness is molded, forming a drum-shaped toothing area with a folding toothing.

A basic idea of the invention is to use a sheet metal workpiece as the starting part, which has a uniform starting wall thickness. In a preforming step, a wall thickness reduction is integrated in one for a first weight optimization cylindrical peripheral wall section performed, wherein a defined target wall thickness is set by spinning. At the same time, the workpiece is axially lengthened in a desired manner. The initial wall thickness of the workpiece can be retained in a partial area of the workpiece, in particular in a radially extending hub area.

In a subsequent final shaping step, the workpiece can be reclamped and a folding toothing can be formed in the cylindrical peripheral wall area provided with a defined target wall thickness. For this purpose, the workpiece is clamped on a correspondingly profiled inner mandrel and at least one toothing roller with a corresponding toothing profile is radially fed in from the outside, the peripheral wall being deformed like a fold. Folded toothing is to be understood here as a toothing in which the toothing is formed both on the inside and on the outside, the target wall thickness previously set remaining almost constant in the course of the fold-like deformation of the cylindrical outer peripheral wall.

For the purposes of the invention, the term toothing is to be understood broadly and is in particular not limited to a meshing gear toothing. Rather, in the sense of the invention, the term toothing also includes other tooth-like shapes, such as groove or keyway profiles, which can be provided as radial stop elements for torque transmission in clutch disk carriers, for example.

Basically, a flat sheet metal part or a deep-drawn part, a forged or a cast part can be used as the starting workpiece. According to a development of the invention, it is particularly advantageous that a round blank or a cup-shaped preform is used as the starting workpiece, in which a hub region is preformed. The hub area runs essentially transversely or radially to the cylindrical peripheral wall. The hub area can be provided with recesses and / or indentations and also with a sleeve-shaped hub.

According to a further advantageous embodiment variant of the invention, it is preferred that the preforming step and / or the final shaping step is carried out in several partial steps in the same workpiece clamping. For example, the preforming step initially consist of an approximately right-angled folding of an outer area of a flat sheet round blank and a subsequent pressure roller or ironing pressure roller, in which the initial wall thickness of the sheet metal part is reduced to the desired target wall thickness.

Several partial steps can also be provided in the final shaping step, which are each carried out in several stages by the radial infeed of different toothing rollers.

Such a reshaping in several sub-steps or stages can prevent overstressing of the workpiece material and thus the occurrence of cracks in the material.

According to a further method variant of the invention, it is preferred that when the folding toothing is formed, the workpiece is held axially and / or radially at its edge region at the open end, which lies opposite a radially extending hub region. Holding at the open edge of the workpiece prevents undesired widening of the workpiece diameter at the edge area. Overall, this also increases the quality of the folding teeth.

It is particularly preferred that axial holding is flexible, in particular pressure-dependent, with length or volume tolerances of the workpiece being compensated for. According to this variant of the invention, a rigid hold is therefore not provided, but a hold which can be released or at least partially released when a predetermined limit pressure or a limit force is exceeded. The holding device can be provided with a corresponding spring device or hydraulic damping elements. In this way, dimensional or material tolerances on the workpiece can be compensated to a certain extent, so that excess material is formed at the edge area, while the folding teeth can be formed with a high degree of accuracy. However, the open end can also be held rigidly if the tolerances in the starting material are small.

Basically, the at least one toothing roller is delivered to the workpiece in a single radial infeed. The gear roller can be axial Have length which corresponds to the axial length of the folding toothing to be introduced. A preferred variant of the method can consist in that the at least one toothed roller is moved axially during the radial infeed or the forming, or is added radially in at least two steps, which are carried out with positions axially offset from one another. In this way, a relatively long folding toothing can also be produced with a shorter toothing roller. An increased flexibility in the forming can be achieved in this way.

For a good stiffening of the open edge of the workpiece, it is advantageous according to a further preferred embodiment variant of the invention that a stiffening area with a preferably greater wall thickness is formed on the edge region of the workpiece. The stiffening area with the large wall thickness can already be set during the preforming step with the press roll or the ironing press roll in that the forming roll stops before the end of the edge area. The material reinforcement can be the initial wall thickness of the workpiece. Alternatively, an additional thickening of the material at the edge region can also be produced by the material displaced during the ironing-pressing process.

A forming system according to the invention, which is designed in particular to carry out one of the methods described above, comprises at least a first forming station which has a main spindle which can be driven in rotation, at least one relatively axially adjustable forming roller and a first clamping element which is designed to clamp a workpiece on the main spindle , at least one second forming station, which has a rotationally drivable inner mandrel with an external toothing, at least one radially adjustable toothing roller and a second clamping element, which is designed to clamp the workpiece on the inner mandrel, and a handling station, which is located between the first forming station and the second forming station arranged and designed for transferring the workpiece after preforming in the first forming station to the second forming station for final forming. The first and second forming station can be identical in that the workpiece is manufactured in two setups at one station.

The advantages described above with the method can be achieved with the forming system according to the invention. The forming stations can be arranged on a common machine bed. The handling station is preferably a multi-axis robot which transfers the workpieces between the forming stations and feeds or removes them.

A preferred embodiment of the forming system according to the invention consists in that the first forming station is designed for pressing and pressure rolling and that the second forming station is designed for profiling. The forming stations can have horizontal or preferably vertical axes of rotation.

According to a development of the invention, it is particularly advantageous that the main spindle of the first forming station and the inner mandrel of the second forming station are directed parallel and vertically. In this way, an overall compact forming system with a small footprint can be created.

For an efficient course of the method, it is further advantageous according to a development of the invention that a first tailstock spindle is assigned to the clamping of the workpiece on the first forming station of the main spindle and a second tailstock spindle in the second forming station to the inner mandrel, the first tailstock spindle and the second tailstock spindle being axial are movably mounted. The tailstock spindles are arranged coaxially to the axis of rotation of the main spindle or the inner mandrel. An axial movement is achieved in particular by corresponding lifting cylinders, which are preferably operated hydraulically.

For a quick changeover, it is also particularly expedient that the main spindle, the inner mandrel, the first tailstock spindle and / or the second tailstock spindle are mounted by means of a quick-change device. The respective component can be quickly replaced by means of the quick-change device. This is particularly economical in terms of maintenance and especially when changing products.

Furthermore, according to a further development of the invention for forming or clamping, it is preferred that the handling station is designed to feed the workpiece to be added and to remove the finished workpiece. The handling station thus not only serves as a pure transfer station between the individual forming stations, but rather serves as a whole for feeding and / or removing the workpieces into or out of the system. The handling station can in particular have at least one multi-axis robot with a corresponding gripping device for gripping the workpiece.

A particularly good shaping is achieved according to an embodiment variant of the forming system according to the invention in that the at least one toothed roller is driven in synchronism with the inner mandrel via a synchronization gear or a rotationally synchronously controlled drive. This ensures that the toothing of the toothing roller is always arranged on the inner mandrel in a corresponding and synchronous manner to the outer toothing. The gear roller and the inner mandrel can be driven by a common drive with a corresponding synchronization gear. Alternatively, the at least one toothing roller and the inner mandrel can each have their own drive, the drives being driven by an electronic control in synchronism with the angle of rotation.

The invention is explained in more detail below on the basis of preferred exemplary embodiments which are shown schematically in the drawings. The drawings show:

Fig. 1:

eine Querschnittsansicht durch ein rotationssymmetrisches Ausgangswerkstück;

Fig. 2:

eine Querschnittsansicht eines nach der Erfindung hergestellten trommelförmigen Getriebeteiles;

Fig. 3:

eine perspektivische Ansicht des Getriebeteiles von Fig. 2;

Fig. 4:

eine vergrößerte Detailquerschnittsansicht einer Faltverzahnung an dem Werkstück nach Figuren 2 und 3;

Fig. 5:

eine perspektivische Ansicht einer erfindungsgemäßen Umformanlage;

Fig. 6:

eine Draufsicht auf die Umformanlage von Fig. 5;

Fig. 7:

eine Vorderansicht eines zweiten Ausführungsbeispiels eines nach der Erfindung gefertigten Getriebeteiles;

Fig. 8:

eine Querschnittsansicht des Getriebeteiles von Fig. 8;

Fig. 9:

eine Vorderansicht eines dritten Ausführungsbeispiels eines nach der Erfindung gefertigten Getriebeteiles;

Fig. 10:

eine Querschnittsansicht des Getriebeteiles von Fig. 9;

Fig. 11:

eine Vorderansicht eines vierten Ausführungsbeispiels eines nach der Erfindung gefertigten Getriebeteiles;

Fig. 12:

eine Querschnittsansicht des Getriebeteiles von Fig. 11;

Fig. 13:

eine Vorderansicht eines fünften Ausführungsbeispiels eines nach der Erfindung gefertigten Getriebeteiles;

Fig. 14:

eine Querschnittsansicht des Getriebeteiles von Fig. 13;

Fig. 15:

eine Vorderansicht eines sechsten Ausführungsbeispiels eines nach der Erfindung gefertigten Getriebeteiles; und

Fig. 16:

eine Querschnittsansicht des Getriebeteiles von Fig. 15.

Fig. 17:

eine perspektivische Ansicht einer weiteren Ausführungsvariante eines erfindungsgemäß hergestellten Getriebeteiles mit kreisrunden Ausnehmungen in der Faltverzahnung; und

Fig. 18:

eine perspektivische Ansicht einer weiteren Ausführungsvariante eines erfindungsgemäß hergestellten Getriebeteiles mit Langlöchern in der Faltverzahnung.

The drawings show:

Fig. 1:

a cross-sectional view through a rotationally symmetrical starting workpiece;

Fig. 2:

a cross-sectional view of a drum-shaped transmission part produced according to the invention;

Fig. 3:

a perspective view of the gear part of Fig. 2 ;

Fig. 4:

an enlarged detail cross-sectional view of a folding toothing on the workpiece Figures 2 and 3 ;

Fig. 5:

a perspective view of a forming system according to the invention;

Fig. 6:

a plan view of the forming system of Fig. 5 ;

Fig. 7:

a front view of a second embodiment of a transmission part made according to the invention;

Fig. 8:

a cross-sectional view of the gear part of Fig. 8 ;

Fig. 9:

a front view of a third embodiment of a transmission part made according to the invention;

Fig. 10:

a cross-sectional view of the gear part of Fig. 9 ;

Fig. 11:

a front view of a fourth embodiment of a transmission part made according to the invention;

Fig. 12:

a cross-sectional view of the gear part of Fig. 11 ;

Fig. 13:

a front view of a fifth embodiment of a transmission part made according to the invention;

Fig. 14:

a cross-sectional view of the gear part of Fig. 13 ;

Fig. 15:

a front view of a sixth embodiment of a transmission part made according to the invention; and

Fig. 16:

a cross-sectional view of the gear part of Fig. 15 .

Fig. 17:

a perspective view of a further embodiment of a transmission part manufactured according to the invention with circular recesses in the folding toothing; and

Fig. 18:

a perspective view of a further embodiment of a transmission part manufactured according to the invention with elongated holes in the folding teeth.

In Fig. 1 a circular or plate-shaped starting workpiece 5, also called workpiece 5, is shown. This has a radially running hub area 6 with a central recess. A thickened peripheral region 7 is arranged in a stepped manner towards the hub region 6. The workpiece 5 can be produced by deep drawing, forging, casting or in another suitable manner.

In a preforming step (not shown), the workpiece 5 is clamped on a rotatably drivable main spindle and axially turned by at least one axially adjustable shaping roller, whereby at the same time an initial wall thickness of the workpiece 5 to a defined target wall thickness of the desired cylindrical peripheral wall 14 is achieved by a basically known ironing roll is formed.

In a subsequent final shaping step, the workpiece 5 preformed in this way is then finally shaped into a drum-shaped gear part 10 which is formed in the Figures 2 and 3 is shown. In this final shaping step, a folding toothing 20 is molded into a toothing region 16 essentially while maintaining the target wall thickness of the cylindrical peripheral wall 14. At an open end, which lies axially opposite the hub region 6 which is not further deformed, the folding toothing 20 is delimited by an annular edge region 18.

The folding teeth 20 formed on the gear part 10 according to the invention is shown in FIG Fig. 4 shown. To form the folding toothing 20, the workpiece 5 is clamped with the cylindrical peripheral wall 14 on an inner mandrel with a corresponding outer toothing and set in rotation. Subsequently, at least one profiled toothing roller is radially advanced, through which the cylindrical peripheral wall 14 is molded or folded into the outer toothing of the inner mandrel essentially while maintaining the target wall thickness. This results in recessed areas 22 and projecting areas 24 which are connected to one another via obliquely directed flanks 26 in the exemplary embodiment shown. The protruding areas 24 can have a wall thickness t1, the flanks 26 a wall thickness t2 and the recessed areas 22 have a wall thickness t3, which differ slightly, in particular by a few tenths of a millimeter, but essentially maintain the target wall thickness previously set in the sense of the invention is.

With the invention, therefore, a weight-optimized gear part 10 can be produced, in which, compared to a hub region 6 with an essentially unchanged wall thickness on a cylindrical peripheral wall 14, a reduced wall thickness is set without cutting, into which the desired folding toothing 20 is then introduced.

A forming system 50 according to the invention is shown schematically in FIGS Figures 5 and 6 shown. A first forming station 60 and a second forming station 70 are arranged on a preferably multi-part machine bed 52. Between the first forming station 60 and the second forming station 70 there is a handling station 80 with a multi-axis robot 82, which has a gripping device 84 for gripping a workpiece and for transferring the workpiece from the first forming station 60 to the second forming station 70.

The first forming station 60 is designed in accordance with a basically known press-rolling machine with a main spindle which can be driven in rotation and which, in the exemplary embodiment shown, is provided for a vertical arrangement. A starting workpiece is fed laterally into the first forming station 60 via a lateral feed device 68, which can also be a multi-axis robot with a gripping device. The supplied work piece is clamped axially on the main spindle with an at least partially cylindrical forming mandrel by means of a first tailstock spindle. The main spindle is then set in rotation with the first tailstock spindle and at least one forming roller is fed to the workpiece. The forming roller axially overflows a peripheral region of the starting workpiece, so that a cylindrical peripheral wall with a defined reduced wall thickness, also called the target wall thickness, is created. The target wall thickness corresponds to the necessary strength conditions which are required for the folding toothing 20 to be molded.

After this first preforming step in the first forming station 60, the clamping of the workpiece is released again and the workpiece is removed from the first forming station 60 by means of the multi-axis robot 82 and transferred to the second forming station 70. In the second forming station 70, the preformed workpiece is axially clamped on an internal mandrel with external teeth by means of a second tailstock spindle. A center axis of the workpiece and a rotation axis of the inner mandrel are also directed vertically.

After the preformed workpiece has been clamped in, the inner mandrel rotates it and at least one profiled toothing roller is then fed radially to the cylindrical peripheral wall of the workpiece. The profile of the gear roller is matched to the profile of the external toothing on the internal mandrel in such a way that the cylindrical peripheral wall is molded or folded into the recesses of the external toothing of the internal mandrel, so to speak. The target wall thickness previously set remains largely unchanged.

After completion of the final shaping step, the fully formed gear part 10 is laterally removed by a removal device 78, which can also have a multi-axis robot with a gripping device.

The forming system 50 according to the invention has a cooling and lubricating device 54 for cooling the hydraulic fluid and a hydraulic station 56 for the various drives, which are in particular hydraulic or electrical drives. Furthermore, a control device 58 is provided, which is arranged in the form of control cabinets.

The handling station 80 is preferably provided with a door 86 so that the handling station can be walked on for operating and maintenance purposes. Furthermore, an operating unit 59 with a monitor and an input terminal is preferably arranged on a front side of the forming system 50.

In the Figures 7 and 8 A second exemplary embodiment of a transmission part 10 produced according to the invention is shown, elongated holes 31 running in the circumferential direction being made in the hub region 6 together with a central opening.

In the third embodiment of a transmission part 10 produced according to the invention according to the Figures 9 and 10 impressions 32 are molded into the hub area. These can be designed to be radially directed and serve to additionally stiffen the hub area 6. The impressions 32 can be formed by a correspondingly designed and shaped main spindle before the preforming step or when clamping in the first forming station 60.

The fourth embodiment of a transmission part 10 according to the invention Figures 11 and 12 also shows impressions 32 molded into the hub area 6, which are more strongly shaped than in the third exemplary embodiment. In the fifth embodiment of a transmission part 10 manufactured according to the invention Figures 13 and 14 a sleeve-shaped hub 34 is arranged on the hub area 6. This sleeve-shaped hub 34 can be formed on the starting workpiece by deep drawing, casting or forging or in some other way. Furthermore, for additional weight optimization in the hub area 6, an annular indentation 35 can be formed, which ensures further weight optimization and space optimization.

In the sixth embodiment according to the Figures 15 and 16 In the gear part 10 according to the invention, a connecting hub 38 directed inwards toward the toothing region 16 is formed. This can have a first section 41 of larger diameter and a second section 42 of smaller diameter, which are connected to one another by a stepped region. Cross bores or cross openings can be provided in the cylindrical wall of the first section 41. Grooves can be formed on the inside of the cylindrical second section 42, which grooves are designed to form a shaft hub connection.

The connecting hub 38 with the first section 41 and the second section 42 can be formed in one piece with the starting workpiece, for example by deep drawing, or alternatively, as in FIG Fig. 16 shown, be produced in two parts by welding.

In addition to the special design of the hub area 6, design variants also lie in an alternative design of the folding toothing 20, as in FIGS Figures 17 and 18 is shown. So are in the folding teeth 20 according to the embodiment of the Fig. 17 Cross bores 44 introduced, which are used for example as a clutch plate carrier for the passage of gear oil.

Similarly, according to the embodiment according to Fig. 18 axial slots 46 can be made in the folding teeth 20. At the end of the folding toothing 20 facing away from the hub region 6, an edge region 18 can be formed with a material thickening to form an annular stiffening region 19.

The in the Figures 7 to 18 Design variants shown of a transmission part 10 produced according to the invention can be combined with one another in any way in their design variants.

Claims (15)

Method for producing a drum-shaped gear part (10) by rotary forming,
characterized, - that in a preforming step a rotationally symmetrical workpiece (5) is set in rotation about its central axis (12) and at least axially infeed and overrun of at least one forming roller, an ironing roll is carried out, a cylindrical peripheral wall (14) having a defined target wall thickness being formed, which is less than an initial wall thickness of the workpiece (5), and - That , in a final shaping step, the preformed workpiece (5) is clamped on an internal mandrel with external toothing and set in rotation and at least one profiled toothing roller is fed radially, through which the cylindrical peripheral wall (14) essentially while maintaining the target wall thickness in the external toothing of the internal mandrel is molded in, a drum-shaped toothing region (16) with a folding toothing (20) being formed. Method according to claim 1,
characterized,
that a circular blank or a cup-shaped preform is used as the starting workpiece (2), in which a hub region (6) is preformed. Method according to claim 1 or 2,
characterized,
that the preforming step and / or the final shaping step is carried out in several partial steps in the same workpiece clamping. Method according to one of claims 1 to 3,
characterized,
that when the folding toothing (20) is formed, the workpiece (5) is held axially and / or radially at its edge region (18) at the open end, which lies opposite a radially extending hub region (6). Method according to claim 4,
characterized,
that axial holding takes place flexibly, in particular as a function of pressure, with length or volume tolerances of the workpiece (5) being compensated for. Method according to one of claims 1 to 5,
characterized,
that the at least one toothing roller is moved axially during radial profiling or is radially advanced in at least two steps, which are carried out with axially offset positions. Method according to one of claims 1 to 6,
characterized,
that a stiffening area (19) with a greater material thickness is formed on the edge area (18) of the workpiece (5). Method according to one of claims 1 to 7,
characterized,
that the hub area (6) is optimized in terms of weight or strength by forming or turning. Forming system, in particular for performing a method according to one of claims 1 to 8, with at least one first forming station (60) which has a main spindle which can be driven in rotation, at least one relatively axially adjustable forming roller and a first clamping element which is designed for clamping a workpiece (5) on the main spindle, - At least one second forming station (70), which has a rotatably drivable inner mandrel with external teeth, at least one relatively radially adjustable toothing roller and a second clamping element, which is designed for clamping the workpiece (5) on the inner mandrel, and - A handling station (80) which is arranged between the first forming station (60) and the second forming station (70) and for transferring the workpiece (5) after preforming in the first forming station (60) to the second forming station (70) for final forming is trained. Forming system according to claim 9,
characterized,
that the first forming station (60) is designed for pressure and pressure rolling and
that the second forming station (70) is designed for profiling. Forming system according to claim 9 or 10,
characterized,
that the main spindle of the first forming station (60) and the inner mandrel of the second forming station (70) are directed parallel and vertically. Forming system according to one of claims 9 to 11,
characterized,
that for clamping the workpiece (10) on a first tool of the main spindle, a first tailstock spindle and an externally toothed inner mandrel as second tool are assigned a second tailstock spindle, the first tailstock spindle and the second tailstock spindle being axially displaceably mounted. Forming system according to one of claims 9 to 12,
characterized,
that the main spindle, the inner mandrel, the first tailstock spindle and / or the second tailstock spindle are mounted by means of a quick-change device. Forming system according to one of claims 9 to 13,
characterized,
that the handling station (80) is designed for feeding the workpiece (5) to be formed and for removing the final-shaped gear part (10). Forming system according to one of claims 9 to 14,
characterized,
that the at least one toothed roller is driven in synchronism with the inner mandrel via a synchronization gear or a rotationally synchronously controlled drive.

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