DE10331713A1 - Tool esp. for non-cutting forming of internal thread for screw connections has turnable forming part and pressure application parts moving along forming curve - Google Patents

Abstract

The tool has a forming part (3) turning about a tool axis (A), a series of pressure application parts (7) moving along a forming curve which extends spirally/helically around the axis. The pressure volumes of the parts are mainly the same. The relative radial distance between pressure application parts increases against the advance direction of the tool. The parts are mounted on an outer surface of a tool core (5) with constant diameter. The forming part is polygonal and has three, four, five, or six corners. The tool has an internal channel for a medium, esp. coolant and/or lubricant, with an outlet at the tool end away from the shaft (2), or near the forming part and/or a guide section (4).

Description

The Invention relates to a tool for chipless production of a thread, in particular for producing an internal thread, and a method for the non-cutting generation of a thread, in particular using of the tool.

To the Producing threads, in particular threads for screw, are various tools known. Much of the tools are in their work area cutting parts or cutting on for cutting Creating the threads. To the cutting thread generating tools counting For example, threading tools, taps and thread milling cutters. A Another form of threading is based on a transformation of the Workpiece. For this are Thread forming tools known and in use by pressure a cold deformation of the workpiece achieve. Among these non-cutting thread producers fall the so-called Thread rolling and the thread rolling. The advantage of these tools is that due to the deformation of the surface and the associated Solidification, the hardness of the material in the region of the thread profile increases and thus a more wear-resistant Thread is generated.

Known Threaded rollers, in particular for internal thread generation include a shaft and a work area. The shaft is usually cylindrical accomplished and with his the workpiece remote end in the chuck of a threaded generating device recorded and held. The workspace is located on the opposite the shaft Side of the thread rolling.

Of the Workspace is spirally revolving along the circumference Provided thread, which is the counter-shape to the thread to be produced represents. In longitudinal section or in the thread profile, the thread generating tool thus has alternating increases or teeth and grooves, which are normally the same each Have distance to each other, which means that the slope of the threads is constant. The teeth are acute in their cross-section substantially radially outward designed to taper. The cross section of a thread on the tool is usually a polygon.

to Creation of a thread, for example in an existing one Bore is the well-known thread furrow ahead with the work area with a corresponding feed and with rotation about the longitudinal axis of the tool shaft inserted into the bore. This will be the teeth of Gewindefurchers in the surface of the workpiece or pressed the bore. The material of the workpiece is doing radially, ie in the direction of the longitudinal axis of the bore in the Recesses or grooves of the working area of the thread rolling crowded.

to Tapered tip of the tool The working range of the thread rolling usually to the Penetration of the first threads into the workpiece surface or to facilitate the inner wall of the bore. The threads in the rejuvenating Section of the work area, also forming part or forming area called cause the deformation of the workpiece or the inner wall of the Bore, that means they create the thread and are accordingly greater loads exposed as the threads in the rest of the work area. Therefore, it is desirable one as possible even load the threads in the rejuvenating Reach the workspace section.

Out DE 1 847 255 U is a Gewindefurcher for non-cutting internal thread generation is known in which the work area consists of a tapered shaping part and a guide member. The Gewindefurcher has seen in cross-section radially outwardly substantially acute-angled threads whose flanks form the pressure surfaces for thread generation. The deformation forces that occur during cold deformation have a loud effect DE 1 847 255 U substantially perpendicular to the thread flanks of the thread rolling. The increase in the action of the threads in the part of the working area which increases in its outer diameter is given by a so-called tempering, that is to say an increase in the outer diameter from the tip to the guide area with the same height of the threads

In order to achieve that the deformation work evenly distributed on the threads of the shaping part, is in the in DE 1 847 255 U disclosed thread furrow provided the front end with arcuate or a bent straight following rising threads. This means that even the first threads have to do a large part of the deformation work and so the work is distributed evenly on the molding part.

In However, practice has shown that despite this constructive measure the threads the shaping part are subjected to different levels of stress, so that the tool is due to the higher wear single threads early must be replaced.

It Now is an object of the invention, a thread-forming tool and a method for threading, in particular using of the thread-forming tool, in which the aforementioned Disadvantages in the prior art at least partially overcome or at least diminished.

These Task becomes regarding the tool for chipless production a thread having the features of claim 1 or independent patent claim 32 and in terms of the method for chipless production of a thread with the features of claim 34 solved. Advantageous embodiments and further developments emerge the claim 1 or claim 32 or claim 34 respectively dependent claims.

The Tool for chipless production of a thread, in particular for Producing an internal thread according to claim 1 comprises at least egg nen about a tool axis rotatable or rotating shaping area along with a spiral or helical (or: helically) circumferential shaping curve successively arranged press studs for generating the thread by pressing into a workpiece surface, wherein Eindrückvolumina the push lug are substantially the same or, in other words, the indentation volumes the press studs over the Shaping curve are substantially constant.

The Tool for chipless production of a thread according to claim 32, optionally on claim 1 or one of claim 1 dependent claims referred back is at least one rotatable about a tool axis or rotating forming area along with the tool axis spirally or helical (or: helically) circumferential shaping curve successively arranged press studs for generating the thread by pressing into a workpiece surface, wherein the shaping area is designed so that on each of the successive pressing lands act essentially the same forming forces.

at the tool according to the invention the tool axis is usually a longitudinal axis of the tool or a central axis passing through the tool. The shaping area can also be referred to as a work area of the tool. The forming curve winds in three dimensions in this workspace Space spiral or helical at a predetermined or predeterminable distance around the tool axis. The shaping curve can then serve a course and a Gradient of a circumferential in the forming area on the tool Forming thread for creating a counter-thread in the workpiece, for example in a bore, to describe.

One Formgebungsgewinde on the tool is approximately the counter-shape to the to be created thread in the workpiece The forming thread usually comprises several threads. One Thread corresponds to a circulation or a turn of the Spiral or helix around the tool. The slope of the forming thread corresponds in the Re gel the slope of the thread to be generated and is in the ideal case about the entire forming area constant. In longitudinal section or in the thread profile Thus, the shaping area essentially has a serrated shape on alternating teeth and grooves.

When pressing lands or shaped wedges are referred to below as the areas of the forming thread, which at least partially penetrate into the workpiece surface to the thread to mold. One thread of the forming thread can several pressing lands or forming wedges. In the borderline case, thus with round cross-section of the Shaping area, would be the forming thread theoretically from threads with infinitely many, built up continuously successive pressure lugs. That would mean, the thread at least partially penetrates the entire circumference the surface a hole. In this case, however, the clamping friction would be with a rotary motion of the tool so high, so that the danger would, that the tool, for example, by tearing off the shaping area would be destroyed. moreover would be a very high energy consumption the result.

Out For this reason, the molding area in practice in cross section nearly a polygons shape on. This ensures that the shaping thread, which then follows the polygonal shape spirally around the tool, only penetrates with its corner areas in the workpiece surface, whereby the Clamping friction is greatly reduced during the rotational movement. A thread of a polygon shaping area can then be so for example include many continuously consecutive press studs or mold wedges how the polygon has corners.

As Eindrückvolumen a Drückstollens is on the one hand, the volume amount in the workpiece, which displaces a pressing lug from a thread groove of the thread to be generated, so the volume amount to the thread groove by immediately consecutive press studs wider and / or deeper in the workpiece surface is notched designated.

In a complementary one or alternative definition is the term indentation volume Also defined as the volume fraction of a pressing tunnel or

Form wedge volume, around which a pressing lug or Mold wedge presses into the material of the workpiece. That means that pressing-in only the volume fraction of the pressing lug is by which this deeper and / or wider presses into the workpiece surface than an immediately preceding pressure tunnel. To the indentation volume on the other hand, the volume fraction of a spinning lug volume is not calculated, in a already formed by a previous press studs Area of thread groove dips. Thus the constant indentation volume deeper and / or wider on each of the consecutive push lugs is pressed into the workpiece surface, can with two immediately consecutive press studs for example, the pressing lug volume by exactly this amount increase - the volume difference of Pressing lobe volumes immediately adjacent press studs be the same - and / or the second press tunnel radially spaced from the tool axis by so much further he exactly the amount of Eindrückvolumens according to Tool protrudes further.

in the Ideal case, so for example in a workpiece from an incompressible Material, then the Eindrückvolumen equal to the difference in the volumes of two immediately consecutive thread grooves and equal to the amount of the impressing Volume fraction of the spinning lug.

at the method for producing a chipless thread according to claim 34, in particular using the tool according to claim 1 or claim 32 or one of claim 1 or claim 32 dependent Claims, will at least one shaping area is rotated around a tool axis, The shaping area is along with one around the tool axis spirally or helical circumferential shaping curve successively arranged press studs moved in a feed direction and become the press studs while the movement in the feed direction pressed into a workpiece surface for the production of thread grooves, wherein opposite to the feed direction immediately consecutive pressing lands a thread groove each to a constant insertion volume enlarge and / or being on each lug act essentially the same forming forces.

The Feed direction of the tool is the direction in which the tool while the thread generating process is moved. The feed direction usually points always in the direction of the workpiece or away from the feed, in which the tool shank is clamped. After completing the thread-forming process, the tool is in a return movement, which takes place counter to the feed direction, unscrewed from the thread produced.

Around now a thread in a workpiece or in one in the workpiece To create introduced bore, so is the tool with the shaping area ahead, with a corresponding feed and while turning around the Tool axis introduced into the hole. The pressing lugs in the forming area have the task of forming the thread in the surface of the hole. At least with the last punch of the forming area is then the desired depth of the thread or the thread groove achieved. The press studs penetrate over their entire height or even partially into the surface of the workpiece.

The Threshing height is the Distance from the press stud bottom or from the outer surface of a tool core to the tip of the push-stalk, with the pusher tip is formed by the point or points of a spinning lug, the or which is spaced radially farthest from the tool axis or are. The lowest point or the lowest points of the groove of the forming thread provides or provide the Stückstollengrund dar. The lateral surfaces usually tapering away from the tool axis pressing lands be as trailing edges designated.

At the push in transferred to the workpiece surface the punching lugs deformation forces on the workpiece. These forces cause the material of the workpiece is displaced from the Eindrückvolumen and at the press edges of the tool for threading increases. The material becomes ie radially and / or tangentially in the recesses or grooves the forming thread of the tool for thread generation urged.

The press studs or mold wedges are exposed in this process to the forces or loads called forming forces. The terms forming force and load here and in the following designate the resulting force from the forces generated during the pressing-in process which acts on the respective pushing flank or pressing surface. The amount of the forming force is dependent on the strength of the material to be machined and the penetration depth of the tool or the displaced volume of material. The trailing edges usually take on the majority of the forming forces acting on the spinning lugs during threading, since the radially outwardly facing pressing surface on the pusher tip is normally much smaller than the area of the pusher flanks.

One the invention according to claim 1 underlying thought is thus that the successive pressing lands the shaping area when penetrating the surface of the workpiece always the same insertion volume repress until the desired or predetermined thread depth is reached. Each immediately consecutive press studs are tuned to always match the predetermined, constant insertion volume penetrate deeper into the thread groove. So they are either each larger or larger by that volume they are radially further by this volume at the forming area in front. Because every punching lug the shaping area substantially the same insertion volume repressed, In general, they also act on each press stud of the forming area in amount or at least approximately on average the same forming forces.

One significant advantage of the design of the press studs in the shaping area according to the invention is that as a result of even distribution the forming forces or the load on the pressure lugs or wedge even wear on the pressing lands or forming wedges occurs, resulting in the life of the tool extended.

In a particularly advantageous embodiment of the tool according to the invention takes the radial distance of successive pusher tips from the tool axis against the feed direction of the tool too. That the shaping area tapered in the feed direction, has For example, the advantage that the penetration of the first press studs into the workpiece surface or the inner wall of the bore is facilitated.

Especially It is advantageous if the tool for chipless production of a Thread includes a tool core and the press studs on the outer surface of the Tool core are arranged. The outer surface of the tool core then forms the pushing lug ground. The outer diameter of the forming area, which is the diameter of one of the press stud tips enveloping Surface described can then be made up of the diameter of the tool core and the height the arranged on this stile together.

In a particularly advantageous embodiment of the tool according to the invention the at least one shaping area in its cross-section approximately one Polygonal shape, preferably with a corner number e in the polygons Form of three or four or five or six. The advantage of polygons form is that the power transmission from the press studs on the workpiece limited only to the corner areas of the polygon, where at the corners pressing lands each radially the largest distance from the tool longitudinal axis have. As a result, there is less force overall for rotating the tool required.

at this embodiment is preferably every e-th of the immediately consecutive Pressing lobe tips on a press tunnel axis arranged, wherein the spinning lug axis in the plan view of the tool parallel to the tool axis runs or tilted by a predetermined angle to the tool axis. In the longitudinal section of the Shaping area or in the forming thread profile increases the Pressing lobe axis with increasing radial distance of the spinning stud tips from the tool axis with respect to the tool axis against the feed direction.

In an embodiment the forming area has a constant tool core diameter on. The tool core diameter is generally equal to the largest diameter the cross-sectional shape of the tool core, measured from the press stud bottom at least one push-stud. The tool core diameter is always smaller than the diameter of the hole in the internal thread should be generated.

Around to achieve an increasing forming area outside diameter, in this case, it is advantageous if the press stud heights and / or the press tunnel cross-sectional areas of the press studs increase in the shaping area against the feed direction. The Pressing tunnel cross-sectional area is the area a pushing lug in the shaping thread profile or in the longitudinal section of the tool along the pinch roller axis.

Especially it is also advantageous if Stollen Stollen volumes the push lug then increase counter to the feed direction. The amount around the the Pressing lobe volumes neighboring press tunnel can then increase preferably the amount of Eindrückvolumens correspond. It may also be advantageous if the pressing-in the volume of a first lug is.

is the shape or size of the cross-sectional area of a pressing lobe known, so lets the volume of a lug calculate with suitable mathematical methods or functions or estimated. Conversely, then, with the same or a different method or functions the cross-sectional area of the following a constant volume of enlarged lugs calculated or estimated become.

At least a punching lug preferably passes over the entire pressure lug height in a workpiece. This can, for example, a last press studs, so the press studs at the largest forming area outside diameter the shaping area or with the greatest radial distance of the spinning stud tip be from the tool axis.

In a particularly advantageous embodiment of the tool according to the invention the shaping area increasing counter to the feed direction Tool core diameter on. The pressure lugs can then on the one hand as before described in their volumes and / or in their cross-sectional areas and / or in their heights become larger against the feed direction.

To the Others, it is particularly advantageous if with increasing tool core diameter the pressing lands have in the shaping area a same pressure lug height and / or a same pressing tunnel cross-sectional area. Due to the increase in the tool core diameter, the forming area outer diameter decreases or the radial distance of the spinning stud tip to the tool axis, so that the successive press studs Press deeper and deeper into the workpiece surface. Around a constantly increasing indentation volume the push lug To achieve the course of the outer surface of the tool core with the help suitable mathematical functions or numerical approximations be adjusted accordingly.

Especially It is advantageous if the pressing tunnel cross sections at least approximately a polygonal shape of the triangles and quadrilaterals, preferably trapeze, comprehensive group of polygonal forms. The shape of the Pressing lobe section For example, by making the tool or application-related Requirements and knowledge may be given, but it can also be be set arbitrarily.

In The practice is preferably approximately the Shape of a triangle or a trapezoid with a very short side at the tiller point, selected. The shape of the press tunnel cross sections For example, in the shaping area, it may be designed such that with the forming thread a metric ISO thread according to DIN 13-1 can generate with a Kernausrundung.

The pressing lands can in the shaping area, the same pressure tunnel cross-sectional shapes exhibit. They then differ only in the size of the cross-sectional area. The may be particularly advantageous in the manufacture of tools, for example, all the press studs with a grinding or milling tool can be generated.

Of Further, it may also be appropriate when the press studs in the shaping area different press tunnel cross-sectional shapes exhibit. By doing so leaves For example, the distribution of forces on the successive ones pressing lands to adapt very precisely. Different cross-sectional shapes can be in practice, for example, achieve that on the entire work area equally trained press studs on the tool shank Be turned away abrading side in the feed direction.

Especially is appropriate it when the pushers approximate in the area of shaping trapezoidal Have cross-sectional shapes and the quotient of an outer width on the one hand and an opposite one Gewindefußbreite on the other hand decreases against the feed direction. The thread foot width is the length the side of the trapezoid adjacent to the tool core. The outer width is the length the trapezoid side at the push-stalk tip, hereby the theoretical length the trapezoid side, that is the distance between the side walls of the trapezium is.

At the push in the successive press studs is in this embodiment the push lug So first a broad base of thread groove formed and the following press studs then form the thread groove mainly in their depth. there can either the thread foot width stay constant, the final Width of the thread groove is then already with the first pressing lug predetermined, or it may increase counter to the feed direction. The outer width can then either be constant or contrary to the feed direction lose weight. In practice, it is particularly preferred if the outer width contrary to the feed direction decreases so much that the pressure lugs in the area of the largest area outside diameter an approximate have triangular cross-sectional shape.

It is particularly advantageous if the pinch roller axis as a function of the tool axis in the longitudinal section of the tool and / or the outer surface of the tool core as a function of the tool axis against the feed direction increases strictly monotonically. The tool can thus be uniformly introduced into the hole, since no steps or edges are to be overcome, which require a greater effort. The course of the press tunnel axis as a function of the tool axis and / or the course of the outer surface of the tool core as a function of the tool axis is or are preferably describable by a mathematical function, in particular a rational or ge rupt function of the nth order, a root or power function, an exponential function or a logarithmic function, or by a numerical approximation, in particular by Lagrangian interpolation polynomials or spline functions, or by a bitmap. Through this optimized course, the distribution of the forming forces can be optimized in addition to the pressing lugs.

In an expedient embodiment of the Tool according to the invention the shaping area adjoins a tool shank for fastening of the tool in a thread generating device.

In a particularly advantageous embodiment is on the tool at least one management area with along a curve about the tool axis spiral or helical curve successively arranged pressing lugs provided on the tool. The management area is limited preferably counter to the feed direction to the shaping area at. That means the leadership area usually between the tool shank and the forming area is arranged.

Of the Radial distance of successive pusher tips from the tool axis in the management area is preferably the same or takes against the feed direction by a predetermined amount and is at the transition from the shaping area in the management area equal to the largest radial Spacing of the tip of the syringe the tool axis of the shaping area.

Of the Shaping area is used to shape the thread. The subsequent management area primarily serves as a guide of the tool in the thread so that provided for threading Force in the shaping area evenly and thus lossless as possible on the surface transferred the workpiece becomes. At the same time, the management area has the function the generated thread surface or the Ge windeflanken to smooth and to calibrate. As a result, the thread can be made very accurately become.

Especially Accordingly, it is advantageous if the spirally or helically revolving Curve the same slope of the spiral or screw as the shaping curve which, as a rule, the slope of the thread to be generated equivalent. Especially in the transition area between Shaping area and guidance area are the pushers adjust accordingly, allowing a constant slope of the curve is reached. It is particularly advantageous if, in addition, the pressing tunnel cross sections all pegs in the guide region are the same and if the press tunnel cross sections all the press studs in the management area equal to the cross sections of the thread grooves of the thread to be generated are. The press studs in the management area form then exactly the opposite form to be generated or produced threads.

takes the radial distance of successive pusher tips from the tool axis or the guide area outer diameter contrary to the feed direction, it has the advantage that the Threading tool without damaging the thread and with less effort into this and out of this again can be turned out. The guide area outside diameter decreases in the area adjacent to the forming area minimum amount, so that, for example, with elastic recovery the generated thread of the force during the feed of the tool is reduced in the bore and at the same time the thread surface is smoothed.

In the area of the guide area adjoining the tool shank, preferably only a few pressing lugs includes the guide area outer diameter preferably very strong. This has the Voteil that a return or reversion facilitates the tool after completion of the thread-forming process and damage the thread produced, for example, by jamming the pressing lugs when Unscrew, is prevented. Due to the continuous increase the pushing lug height or of the guide area outside diameter from the shaft to the shaping area, the tool is turning back clean and without tilting in the already produced thread out.

In a particularly advantageous embodiment are on the periphery of Tool, preferably at the molding area and / or at the guide area longitudinal extending grooves provided for guiding a fluid medium, especially a cooling and / or lubricant. When threading process can the working area due to the friction between the tool and the surface of the workpiece warm up a lot. To the friction and / or the heat development can then reduce and dissipate the heat generated a cooling and / or Lubricant in the grooves from the tool shank to the top of the tool Tool guided and from there overflow the shaping area and the guidance area. The longitudinal extending grooves can preferably also as swirl grooves, ie twisted or with a Rotation around the circumference of the tool to be formed.

A another possibility a fluid medium to the tool tip or to shaping area and / or guide region to guide is inside the tool, preferably along the Longitudinal axis one Provide channel, preferably facing away from the tool shank on the End of the tool, ie at the tool tip, or laterally in front of or after the at least one shaping area and / or guiding area exit.

Around to ensure, that on the individual press studs of the shaping area have essentially the same forming forces, can the tool for threading in a particularly advantageous embodiment be formed so that the press studs with force actuators in operative connection are for controlling or regulating the forming forces. It is known the precision a tool over Adjust sensors that are located directly at the point of action (BMBF research project: Accomat).

in the For example, it is conceivable within the scope of the present invention Piezo elements in to integrate the tool in particular in the press studs, the on the one hand, on the press studs acting forming forces, in particular, compressive forces, could turn into electronic signals that are used to control and Regulation of the process can serve. The Piezo elements could on the other hand by applying a voltage and pressure impulses on the pressing lugs transferred to the tool surface.

The Invention will be described below with reference to embodiments and below With reference to the accompanying drawings further explained.

It show each:

1 a perspective view of a known tool for chipless thread generation,

2 an enlarged perspective view of the shaping region of the tool according to 1

3 1 is a schematic representation of the forming forces acting on the pressing lugs of the forming area in a thread-forming process,

4 FIG. 2 a schematic representation of an embodiment of the shaping region according to the invention and a cross section of the thread grooves produced herewith, FIG.

5 a schematic representation of another modified embodiment of the shaping area according to 4 and a cross section of the thread grooves produced herewith,

6 a schematic representation of another modified embodiment of the shaping area according to 4 and a cross section of the thread grooves produced herewith,

7 a schematic representation of another modified embodiment of the shaping area according to 4 and a cross section of the thread grooves produced herewith,

8th a schematic representation of a further modified embodiment of the shaping region according to the invention,

Corresponding parts and sizes are in the 1 to 8th provided with the same reference numerals.

1 and 2 show a known thread rolling 1 the one tool shank 2 and two work areas, namely a molding area 3 and a leadership area 4 includes. The thread fork 1 serves for non-cutting internal thread production.

The tool shank 2 For example, it can be cylindrical and, as a rule, carries a square (not shown here) on the side introduced in the chuck for the transmission of momentum. The tool shank 2 here is solid with the adjacent guidance area 4 connected, that means the tool shank 2 and the workspaces 3 . 4 are made in one piece. The workspaces 3 . 4 have a polygonal cross-section that has approximately the shape of a triangle.

In the shaping area 3 and in the management area 4 is at a tool core 5 which also has an approximately triangular cross-section, a forming thread 6 with punching lugs 7 educated. Each thread of the forming thread 6 So every turn around the tool core 5 in this case includes three push lugs 7 , One in three of the pressing lugs immediately adjacent to each other along the forming thread 7 is with a push stud tip 10 arranged on a spinning lug axis D, which is parallel to a tool axis A in plan view. The pressing lugs are thus arranged axially one behind the other on the corners of the polygonal tool core. In principle, it is also possible that the pressing lug axis D is inclined at a predetermined angle to the tool axis A. This can be done, for example, by a press stud arrangement on a polygonal tool core 5 be realized, in particular a certain Twist around the tool axis A has.

The press studs 7 make up near the work area core 5 inner oblique pressure edges 8th and to these radially outwardly subsequent outer pressure surfaces 9 , The one or more points on the outer pressing surfaces 9 with the largest radial distance to the tool axis A form the Stollenstollenspitze 10 ,

Will now the thread furrow 1 in a feed direction (in 1 and 2 shown with an arrow) introduced into a hole, so form the press studs 7 of the forming area 3 a thread in the inner wall of the hole. They penetrate along the forming thread 6 immediately consecutive press studs 7 in each case by the Eindrückvolumen deeper and / or wider in the workpiece surface until a last press studs 7 of the forming area 3 the thread forms in its full depth and width.

Upon further rotating movement of the thread rolling 1 in the feed direction calibrate and smooth the following pressure lugs 7 of the management area 4 the generated thread grooves. The press studs 7 in the management area 4 are therefore tuned in their dimensions and in their shape exactly to the thread to be produced. The to the shaping area 3 adjacent press studs 7 of the management area 4 generally correspond in cross-sectional shape and in dimensions to the adjacent press stud (s) 7 of the forming area 3 , Contrary to the feed direction can then in the guide area 4 the radial distance of the pusher tips 10 from the tool axis A by a small amount (off 1 not seen) to reduce the friction in the thread produced and compensate for a normally occurring elastic deformation of the material. The stresses in the material resulting from the elastic deformation would otherwise put pressure on the pressure lugs 7 of the management area 4 act, which additionally increases the friction during the feed movement.

3 shows schematically how the forming forces U can act on the pressing lugs of the shaping area. The forming forces when penetrating a pusher 7 into the workpiece 11 include, among others, frictional forces and compressive forces. The forming forces U shown in the drawing represent only theoretical resulting forming forces on the spinning edges 8th or the outer lug surface 9 can act.

Also is the 3 No information about the height of the forming forces. The amount of forming forces depends, among other things, on the type or strength of the material and on the displaced volume. At which point the largest forming forces on the pressing lug 7 attack is in turn dependent on the spinning tunnel cross-sectional shape. However, most of the forming forces usually act on the trailing edges 8th ,

The material is at the penetration of the pressing lugs 7 into the forming thread grooves 12 repressed. By doing that, by every lug 7 essentially the same volume amount, the Eindrückvolumen the Schlückstollens 7 corresponds to, is displaced, act on each pressing tunnel also approximately the same forming forces U.

In 4 to 8th different embodiments of the shaping region of the tool according to the invention are shown. The figures each show the thread profile of the forming thread in a longitudinal section of the tool along the tool axis A and the pinch roller axis D. In 4 to 7 In addition, the cross sections G of the thread grooves generated with the thread profile are shown. They illustrate that along a forming thread 6 successively arranged press studs 7 are formed so that of immediately consecutive press studs 7 essentially the same insertion volume is displaced. This will be at the in 4 to 7 shown tools with a constant tool core diameter achieved by corresponding enlargement of the pressing tunnel cross-sectional areas of the immediately consecutive press studs.

In the in 4 to 8th Forming thread profile shown is along the tool core 5 only every e-th push lug 7 in the spinning tunnel cross-section (or: in the longitudinal section along the tool axis A), since the shaping region has in its cross-section orthogonal to the tool axis A approximately the shape of a polygon with a number of corners e. Different consecutive press tunnel cross sections are conceivable in order to produce a thread groove. The pitch P of the forming thread 6 is in all illustrated forming thread profiles ( 4 to 8th ) along the tool core constant.

5 shows in the shaping thread profile, for example, triangular press tunnel cross-sections, wherein the Stollen tunnel cross-sectional shape in the entire shaping region is almost equal. Also in 6 shown pressing tunnel cross-sections have the same cross-sectional shape, however, the pressing lugs are trapezoidal here.

In 4 and in 7 on the other hand, the pressure tunnel cross-sectional shape changes along the tool core 5 , The press tunnel cross sections in 4 and 7 have approximately trapezoidal cross cut forms, wherein the quotient of an outer width 13 and an opposite thread foot width 14 along the tool axis A decreases. When impressing the successive pressing lugs so initially a broad base of the thread groove is formed and the following press studs then form the thread groove mainly in their depth. At the in 7 illustrated press studs 7 even decreases the outer width so much that the pressure lugs finally have an approximately triangular cross-sectional shape.

In 8th is a forming thread profile shown at the tool core 5 increasing in diameter, with the press studs 7 have the same pressure lug height. The increase in the tool core diameter ensures that the successive press studs 7 to push a constant insertion volume further into the workpiece surface. The necessary increase in the tool core diameter or the tool core outer surface can be described and calculated, for example, by a mathematical function.

1

forming taps

2

tool shank

3

shaping area

4

guide region

5

tool core

6

forming thread

7

pressing lands

8th

pushing flanks

9

outer pressing surfaces

10

Pressing lobe tip

11

workpiece

12

Forming thread grooves

13

external width

14

Gewindefußbreite

A

tool axis

D

Pressing lobe axis

G

cross sections a thread groove

P

pitch of the forming thread

U

forming forces

Claims (35)

Tool for the non-cutting production of a thread, in particular for producing an internal thread, comprising a) at least one forming region (A) rotatable or rotating around a tool axis ( 3 ) with b) along a tool axis (A) spirally or helically encircling shaping curve successively arranged pressing lugs ( 7 ) for generating the thread by pressing into a workpiece surface, c) wherein Eindrückvolumina the pressure lugs ( 7 ) are substantially the same. A tool according to claim 1, wherein the radial spacing of successive tiller spikes (FIG. 10 ) increases from the tool axis (A) against a feed direction of the tool. Tool according to claim 1 or claim 2 with a tool core ( 5 ), whereby the pressure lugs ( 5 ) on an outer surface of the tool core ( 5 ) are arranged. Tool according to one or more of the preceding claims, wherein the at least one shaping region ( 3 ) has approximately a polygonal shape in its cross section, preferably with a corner number e in the polygonal shape of three or four or five or six. A tool according to claim 4, wherein each e-th of the immediately successive tiller lugs ( 10 ) is arranged on a spinning lug axis (D) and the spinning lug axis (D) in the plan view of the tool parallel to the tool axis (A) or inclined by a predetermined angle to the tool axis (A). Tool according to one or more of claims 1 to 5, wherein the shaping area ( 5 ) has a substantially constant tool core diameter. Tool according to one or more of claims 1 to 5, wherein the shaping area ( 3 ) has an opposite to the feed direction increasing tool core diameter. Tool according to claim 7, wherein the pressing lugs ( 7 ) in the forming area ( 3 ) have a same pressure lug height. Tool according to claim 7 or claim 8, wherein the pressing lugs ( 7 ) in the forming area ( 3 ) have a same Stollen tunnel cross-sectional area. Tool according to one or more of claims 1 to 7, wherein the pressing lug heights of the pressing lugs ( 7 ) increase counter to the feed direction. Tool according to one or more of claims 1 to 7 and claim 10, wherein the pressing lug cross-sectional areas of the pressing lugs ( 7 ) increase counter to the feed direction. A tool according to one or more of claims 1 to 7 and claim 10 or claim 11, wherein thrust lug volumes of the pressing lugs ( 7 ) Increase against the feed direction. The tool according to claim 12, wherein the pressure lug volumes of the adjacent pressure lugs ( 7 ) increase counter to the feed direction by the amount of Eindrückvolumens. A tool according to claim 13, wherein the indentation volume is the volume of a first thrust lug (16). 7 ). Tool according to one or more of claims 1 to 14, wherein at least one pressing lug ( 7 ) over the entire pressure lug height in a workpiece ( 11 ) penetrates. Tool according to one or more of the preceding Claims, wherein the pressing tunnel cross sections at least approximately a polygonal shape of the triangles and quadrilaterals, preferably trapeze, comprehensive group of polygonal forms. Tool according to one or more of claims 1 to 16, wherein the pressing lugs ( 7 ) in the forming area ( 3 ) have same Stollen cross-sectional shapes. Tool according to one or more of claims 1 to 16, wherein the pressing lugs ( 7 ) in the forming area ( 3 ) have different press tunnel cross-sectional shapes. The tool according to claim 18, wherein the press studs ( 7 ) have approximately trapezoidal cross-sectional shapes and the quotient of an outer width ( 13 ) on the one hand and an opposite thread foot width ( 14 ) on the other hand decreases against the feed direction. Tool according to one or more of the preceding claims, wherein the pressing lug axis (D) as a function of the tool axis (A) in the longitudinal section of the tool and / or the outer surface of the tool core ( 5 ) as a function of the tool axis (A) against the feed direction increases or increases strictly monotonically. Tool according to claim 20, wherein the course of the spinning lug axis (D) as a function of the tool axis (A) and / or the course of the outer surface of the tool core ( 5 ) as a function of the tool axis (A) is or are by a mathematical function, in particular a rational or fractionally rational function nth order, a root or power function, an exponential function or a logarithmic function, or by a numerical approximation, in particular by Lagrangian interpolation polynomials or spline functions, or by a bitmap. Tool according to one or more of the preceding claims, wherein the shaping area ( 3 ) to a tool shank ( 2 ) for attaching the tool in a thread generating device adjacent. Tool according to one or more of the preceding claims, wherein at least one guiding area ( 4 ) having along a about the tool axis (A) spirally or helically encircling curve successively arranged pressing lugs ( 7 ) is provided on the tool. The tool according to claim 23, wherein the guidance area ( 4 ) against the feed direction to the forming area ( 3 ) adjoins. A tool as claimed in claim 23 or claim 24, wherein the radial spacing of successive tiller lobes (Fig. 10 ) from the tool axis (A) in the guide area ( 4 ) is equal to or decreases counter to the feed direction by a predetermined amount and at the transition of shaping area ( 3 ) in the management area ( 4 ) equal to the largest radial distance of the tiller lugs ( 10 ) from the tool axis (A) of the forming area (FIG. 3 ). Tool according to one or more of claims 23 to 25, being the spiral or helical circumferential curve the same slope of the spiral or screw as the shaping curve has. Tool according to one or more of claims 23 to 26, wherein the pressing lug cross sections of all the pressing lugs ( 7 ) in the management area ( 4 ) are the same. A tool according to claim 27, wherein the pressing lug cross sections of all the pressing lugs ( 7 ) in the management area ( 4 ) are approximately equal to the cross sections of the thread grooves of the thread to be produced. Tool according to one or more of the preceding claims, wherein at the periphery of the tool, preferably in the forming area ( 3 ) and / or in management ( 4 ) extending in the longitudinal direction are provided for guiding a fluid medium, in particular a coolant and / or lubricant. The tool of claim 29, wherein the longitudinal extending grooves are formed as swirl grooves. Tool according to one or more of the preceding claims, wherein inside the tool, preferably along the factory tool axis (A), a channel is provided for guiding a fluid medium, in particular coolant and / or lubricant, preferably at the tool shank ( 2 ) facing away from the end of the tool or laterally before or after the at least one shaping area ( 3 ) and / or management area ( 4 ) exit. A tool for the non-cutting production of a thread, in particular with reference to one or more of the preceding claims, comprising a) at least one forming area (A) rotatable or rotating about a tool axis ( 3 ) with b) along a tool axis (A) spirally or helically encircling shaping curve successively arranged pressing lugs ( 7 ) for producing the thread by impressing into a workpiece surface, c) wherein the shaping area is designed such that on each of the press studs ( 7 ) act essentially the same forming forces (U). A tool according to claim 32, wherein the pressure lugs ( 7 ) are in operative connection with force actuators for controlling or regulating the forming forces (U). Method for chipless production of a thread, in particular using the tool according to one or more of the preceding claims, a) in which at least one shaping region ( 3 ) is rotated about a tool axis (A), b) in which the shaping area (A) 3 ) having along a tool axis (A) spirally or helically encircling shaping curve successively arranged pressing lugs ( 7 ) is moved in a feed direction and c) in which the pressing lugs ( 7 ) are pressed during the movement in the feed direction in a workpiece surface for the production of thread grooves, d) wherein opposite to the feed direction directly consecutive press studs ( 7 ) increase a thread groove in each case by a constant indentation volume and / or wherein on each pressing lug ( 7 ) act essentially the same forming forces (U). A method according to claim 34, wherein the pressure lugs ( 7 ) one against the feed direction to the forming area ( 3 ) adjacent management area ( 4 ) smooth the surface of the thread produced and / or calibrate the thread produced.