US20230241667A1

US20230241667A1 - Modular Forming Tool, Modular Forming Tool Set and Method for Producing Substantially Rotationally Symmetrical Parts

Info

Publication number: US20230241667A1
Application number: US18/010,287
Authority: US
Inventors: Hilmar Gensert
Original assignee: Kamax Holding GmbH and Co KG
Current assignee: Kamax Holding GmbH and Co KG
Priority date: 2020-06-24
Filing date: 2021-05-27
Publication date: 2023-08-03
Also published as: CN116033977A; WO2021259586A1; DE102020116567A1; DE102020116567B4; EP4171844A1; MX2022016435A

Abstract

Modular forming tool (1), in particular pressing tool, preferably for producing essentially rotationally symmetrical parts, comprising at least one primary tool (10), in particular a core, at least one reinforcing tube (30) and at least one auxiliary tool (50), the forming tool (1) extending along a longitudinal extension direction (L), the primary tool (10) having a workpiece machining surface (12), a sheath surface (14) and two end surfaces (16), the workpiece machining surface (12) contacting or being designed to contact a workpiece, the sheath surface (14) delimiting the primary tool (10) in a radial direction (R), wherein the end surfaces (16) delimit the primary tool (10) in the longitudinal extension direction (L), wherein the reinforcing tube (30) has an inner sheath surface (32) and an outer sheath surface (34), wherein the primary tool (10) is pressed into the reinforcing tube (30) indirectly and/or directly via the sheath surface (14), so that the primary tool (10) is secured relative to the reinforcing tube (30) in the radial direction (R), wherein the inner sheath surface (32) and the outer sheath surface (34) each have an interference fit, wherein the auxiliary tool (50) is bounded in the longitudinal direction of extension (L) by cover surfaces (56), wherein the auxiliary tool (50) is bounded outwardly in the radial direction (R) by a circumferential surface (54), and wherein the circumferential surface (54) has a clearance fit in the radial direction (R).

Description

The invention relates to a modular forming tool and a modular forming tool set, in particular for producing substantially rotationally symmetrical parts, such as bolts, in particular also eccentric bolts, or screws.
Forming tool sets are already known from the prior art. They are used to transform a workpiece blank into a defined forming geometry by means of, in particular, multi-stage plastic deformation—usually by means of non-cutting machining. For this purpose, a workpiece blank is introduced between a punch and a die of the forming tool set, wherein the workpiece blank is specifically formed by the relative movement of the punch to the die. To achieve this forming, the punch and/or die has a core, the core directly contacting the workpiece to effect forming of the work-piece. The forces that occur during forming are usually very high, especially during cold forming. To prevent displacement of the core or cores, the forming tools of the forming tool set usually have positioning aids which support the cores or core in the direction of the relative movement—between the die and the punch—in a force-locking manner with respect to it. Due to the large number of components involved and the individuality of the tools for each individual product, the dimensioning and design of the forming tools is very extensive and cost-intensive in the case of known forming tools.
It is therefore the object of the present invention to reduce the costs involved in the design and maintenance of forming tools and, at the same time, to enable safe production of workpieces.
This object is solved with a forming tool according to claim 1, with a modular forming tool set according to claim 14 and by a manufacturing method according to claim 15. Further advantageous features and embodiments result from the subclaims, the description and the figures.
According to the invention, a modular forming tool, in particular a pressing tool, preferably for producing essentially rotationally symmetrical parts, comprises at least one primary tool, in particular a core, at least one reinforcing tube and at least one auxiliary tool, wherein the forming tool extends along a longitudinal extension direction, wherein the primary tool has a workpiece machining surface, a sheath surface and two end surfaces, wherein the workpiece machining surface contacts or is designed to contact a workpiece, wherein the sheath surface delimits the primary tool in a radial direction, wherein the end surfaces bound the primary tool in the longitudinal extension direction, wherein the reinforcing tube has an inner sheath surface and an outer sheath surface, wherein the primary tool is pressed into the reinforcing tube indirectly and/or directly via the sheath surfaces, so that the primary tool is secured relative to the reinforcing tube in the radial direction, wherein the inner sheath surface and the outer sheath surface each have an interference fit, wherein the auxiliary tool is bounded in the longitudinal direction of extension by cover surfaces, wherein the auxiliary tool is bounded radially outwardly by a circumferential area, and wherein the circumferential area has a clearance fit in the radial direction. The modular forming tool is thereby in particular a press tool, wherein the modular forming tool serves to be used in a forming manufacturing step or in a forming manufacturing process. Preferably, the modular forming tool is used to produce essentially rotationally symmetrical parts, such as bolts or screws. These essentially rotationally symmetrical parts are, in particular, parts which are preferably at least in sections rotationally symmetrical about an axis, wherein these parts may have spiral-like external contours, such as a thread, or tool engagement contours which may destroy or break the perfect rotational symmetry of these parts. For example, in this context, bolts, eccentric bolts or screws, among others, are substantially rotationally symmetrical parts within the meaning of the invention. In other words, the modular forming tool may be used to form a workpiece such that a substantially rotationally symmetrical part such as a bolt or screw is created. The modular forming tool comprises a plurality of different modules, wherein the modular forming tool comprises at least one primary tool, at least one reinforcing tube, and at least one auxiliary tool. The modular forming tool thereby extends along a longitudinal extension direction. The longitudinal extension direction of the forming tool is in particular the direction in which the length of the modular forming tool is determined and/or around which the forming tool is built. In other words, the forming tool and/or the reinforcing tubes and/or the auxiliary tools and/or the primary tools may be arranged in an assembled state in such a way that they surround or enclose the longitudinal extension direction. Alternatively or additionally preferably, the longitudinal extension direction can also be the direction in which the workpiece mainly extends and/or in which the forming tool moves during the forming of the workpiece. The primary tool of the modular forming tool is used to contact the workpiece machining surface of the primary tool with a workpiece in such a way that the workpiece is formed by this contact. In other words, this may mean that the workpiece machining surface is the surface of the primary tool that contacts or can contact the workpiece for forming the workpiece. In particular, the primary tool is formed as a core, preferably made of hard metal. In this context, a core can be understood to mean that the primary tool is in particular such that, viewed in the radial direction, it at least partially forms an inner core of the modular forming tool, which is, however, preferably hollow (e.g. tubular). In particular, therefore, the primary tool is formed in such a way that the workpiece machining surfaces and/or the workpiece machining surface of the primary tool delimit or bound the primary tool inwardly in the radial direction. In addition to the workpiece machining surface, the primary tool also has a sheath surface and two end surfaces. The sheath surface limits the primary tool in the radial direction, in particular outwardly. In other words, this can mean that the sheath surface forms the part of the respective primary tool facing outward in the radial direction. In this case, the radial direction extends perpendicular to the longitudinal extension direction. In other words, this can mean that the radial direction points radially away from the longitudinal extension direction. In particular, the sheath surface of the primary tool is formed at least substantially rotationally symmetrical to or about the longitudinal extension direction. In this context, at least substantially rotationally symmetrical means that the sheath surface is formed primarily by a cylindrical surface about the longitudinal direction of extension. However, recesses or bores may be recessed or introduced in the sheath surface, which represent a slight deviation from the ideal rotational symmetry, wherein a substantially rotationally symmetrical design about the longitudinal extension direction of the sheath surface is still to be given in the case of this slight deviation. In the longitudinal extension direction, the primary tool is limited by the end surfaces. In particular, the end surfaces are such that they have a normal which is substantially parallel to the longitudinal extension direction. In other words, the end surfaces of the primary tool are substantially planar, wherein this plane in which the respective end surface lies has a normal which is substantially parallel to the direction of longitudinal extension. Essentially parallel in the sense of the invention are two directions in particular if the included angle between these two directions is at most 1° preferably at most 0.5° and more preferably at most 0.1°. Particularly preferably, the modular forming tool has a plurality of primary tools, in particular 2, 3 or 4 primary tools, which advantageously can all have the features described above. Advantageously, these primary tools are designed or arranged within the modular forming tool in such a way that they each have an end surface which directly contacts an end surface of a further primary tool. In other words, this can mean that the primary tools can be arranged next to or behind each other in the longitudinal direction in such a way that they make direct contact with each other. In this way, a particularly compact modular forming tool can be achieved. Advantageously, each of these primary tools forms part of a core of the modular forming tool. In addition to the primary tool, the modular forming tool also comprises at least one reinforcing tube. The reinforcing tube has an inner sheath surface and an outer sheath surface. The inner sheath surface limits the reinforcement tube inwardly in the radial direction and the outer sheath surface limits the reinforcement tube outwardly in the radial direction. It is/are expedient that the inner sheath surface and/or the outer sheath surface of the reinforcing tube, preferably of all reinforcing tubes, is/are formed at least substantially rotationally symmetrical to or about the longitudinal extension direction.
Advantageously, both the inner sheath surface and the outer sheath surface are formed at least substantially rotationally symmetrical about the longitudinal extension direction. This essentially rotationally symmetrical design of the inner sheath surface and/or of the outer sheath surface of the reinforcing tube or of all reinforcing tubes of the forming tool can result in a particularly high mechanical load-bearing capacity of the reinforcing tube and in the reinforcing tubes being able to be produced particularly inexpensively. The primary tool, in particular all primary tools, are pressed into a reinforcing tube via the sheath surface of the respective primary tool. For this purpose, the sheath surface of the primary tool forms an interference fit with an inner sheath surface of at least one reinforcing tube. This interference fit between the inner sheath surface of the reinforcing tube and the sheath surface of the primary tool prevents or impedes displacement of the primary tool in the radial direction with a positive fit and in the longitudinal direction with a frictional fit (interference fit) relative to the reinforcing tube. Advantageously, each primary tool is pressed into a reinforcing tube in this way. An interference fit means that there is an interference fit between the two contacting surfaces of the components. The interference fit prevents any displacement between the respective primary tool and the reinforcement tube. In an assembled or installed or mounted state of the modular forming tool, the inner sheath surface and the outer sheath surface of the reinforcing tubes or of the reinforcing tube of the modular forming tool are in particular designed or arranged in such a way that at least the inner sheath surface and, advantageously, also the outer sheath surface in each case form an interference fit with a further component. These interference fits can, for example, be interference fits between a reinforcing tube and a primary tool or, alternatively and preferably, a reinforcing tube can also be pressed into a further reinforcing tube. In addition, preferably, a reinforcing tube can also form an interference fit with a tool holder, in particular via the outer casing surface. Advantageously, therefore, each reinforcing tube can be press-fitted in a different component. In particular, the tool receptacle is the component of the forming tool that surrounds and/or receives the reinforcing tube(s), the auxiliary tool(s) and the primary tool(s). In particular, the tool receptacle therefore limits the forming tool in the radial direction or radially outward. Advantageously, the tool receptacle has an inner sheath surface which is also cylindrical and/or substantially rotationally symmetrical about the longitudinal extension direction. Advantageously, this inner sheath surface is arranged in the forming tool in such a way that it can contact, or in an assembled state contacts, the outer sheath surfaces of the reinforcing tubes of the forming tool and/or the circumferential area of the auxiliary tools, which have the largest radial dimension. In addition to the reinforcing tube and the primary tool, the forming tool also comprises at least one auxiliary tool, preferably a plurality of auxiliary tools. This auxiliary tool or the auxiliary tools of the modular forming tool have cover surfaces in the longitudinal direction of extension. In other words, the auxiliary tool is therefore bounded in the longitudinal extension direction by the cover surfaces, in particular completely by the cover surfaces. Advantageously, these cover surfaces are flat and/or each have a normal which is essentially parallel to the longitudinal direction. In addition to the cover surfaces, the auxiliary tool also has a circumferential surface which delimits the auxiliary tool outwardly in the radial direction, in particular the auxiliary tool is delimited outwardly in the radial direction exclusively by the circumferential surface. In other words, the circumferential surface is the surface which limits the auxiliary tool outwardly in the radial direction. This circumferential surface is advantageously designed to be essentially rotationally symmetrical with respect to the longitudinal extension direction, in order to achieve simple and inexpensive manufacture of the auxiliary tool. In addition, a particularly mechanically loadable design of the auxiliary tool can also be achieved in this way. The rotary surface is designed in such a way that it has a clearance fit in the radial direction. A clearance fit in this context means that the rotating surface of the at least one auxiliary tool, preferably of all auxiliary tools, has a clearance or undersize in relation to the nominal or nominal diameter. Alternatively or additionally preferably, a clearance fit in this context can also be understood to mean that the auxiliary tool has a clearance fit or a spatial clearance in relation to the part directly surrounding it in the assembled state, which can in particular be a tool holder. The auxiliary tools of the modular forming tool serve primarily to be able to absorb axial forces in a form-fitting manner from the reinforcing tubes and/or the primary tools during the machining operation along the longitudinal extension direction. Advantageously, the auxiliary tools themselves are in turn also held positively in the tool holder, at least in the direction in which the machining forces act during forming of the workpiece. This positive support of the primary tool enables the primary tools and the reinforcement tubes to be securely fixed. The clearance fit of the auxiliary tools in the radial direction ensures that the rotating surface of the auxiliary tools should transmit just no shear forces, or at least only very low shear forces. The modular design of the forming tool, comprising primary tools, reinforcing tubes and auxiliary tools, makes it possible to achieve a particularly cost-effective and simple design, because both the reinforcing tubes and the auxiliary tools, as well as the primary tools, have simple geometric shapes which can be assembled in a manner similar to a modular system to obtain a modular forming tool, while at the same time enabling safe production of the workpiece through safe positioning of the tool surfaces.
It is expedient that the auxiliary tools and/or the reinforcement tubes and/or the primary tools are formed in one piece. In this way, it can be achieved that these components can also withstand high loads.
Advantageously, the forming tool has a tool holder, in particular an outer tool holder, with all primary tools, reinforcement tubes and auxiliary tools of the forming tool extending at least partially inside the tool holder. The tool holder therefore forms, in particular, the radially outward bounding enclosure of the forming tool in the radial direction. In other words, the tool receptacle can therefore serve as or form a kind of surrounding, in particular cylindrical, outer boundary of the forming tool. Advantageously, the tool receptacle has a continuous, in particular central, recess and/or an inner sheath surface which, for example, may also be formed at least partially by the recess. This recess or this inner sheath surface advantageously extends in the longitudinal direction, wherein all primary tools, reinforcing tubes and auxiliary tools of the forming tool can be arranged or—in an assembled state—are arranged within this recess or in the volume spanned by the inner sheath surface. However, it cannot be ruled out that at least some parts of the primary tools, the reinforcing tubes and/or the auxiliary tools may also be located partially outside the outer tool holder, viewed in the direction of longitudinal extension. In other words, this may mean that advantageously each primary tool, reinforcing tube and/or auxiliary tool is located or extends at least partially—in an installed state—within the tool receptacle, in particular within the recess and/or within the volume spanned by the inner sheath surface. By providing an outer tool receptacle, a particularly high mechanical load-bearing capacity of the modular forming tool is achieved, so that a particularly secure positioning can take place. In addition, this can also ensure that particularly high forming forces can be safely applied to the workpiece. The tool holder is designed in particular as a single piece so that it can also withstand high mechanical loads. It is expedient that at least one auxiliary tool is supported indirectly and/or directly in a form-fitting and/or force-fitting manner relative to the tool holder, in particular in a positive and/or negative direction along the longitudinal extension direction, in order to be able to safely absorb and dissipate the high forces on the primary tools and/or the auxiliary tools that occur during forming.
Advantageously, at least one cover surface of an auxiliary tool directly contacts a reinforcement tube and/or a primary tool. In this way, a particularly secure form-fit positioning of the reinforcement tube and/or the primary tool can be achieved, in particular in the direction of longitudinal extension. In addition, this can also relieve the press fit between the primary tool and the reinforcing tube surrounding the primary tool, so that material and/or weight can be saved on the reinforcing tubes. Direct contact in this context means that the top surface of the auxiliary tool is intended to make direct contact with the reinforcing tube and/or a primary tool, in particular with its end surface.
It is expedient that at least one cover surface of an auxiliary tool is free of reinforcement tube contact and/or primary tool contact. Free of reinforcement tube contact and/or free of primary tool contact means that at least one cover surface of at least one auxiliary tool has no direct or indirect contact with a reinforcement tube and/or with a primary tool. The decisive factor for this determination is in particular the assembled state of the forming tool. In other words, this auxiliary tool can act as a mere positioning aid, similar to a relining disc.
Advantageously, all auxiliary tools in the modular forming tool are designed or arranged in such a way that they have a maximum of one cover surface which is in contact with a reinforcement tube and/or with a primary tool. This design or arrangement of the cover surface or cover surfaces of the auxiliary tools in relation to the reinforcing tubes and/or to the primary tools ensures that the auxiliary tools are loaded in particular in only one direction, advantageously exclusively in the positive or negative longitudinal direction. In particular, this can save manufacturing costs, because the cover surfaces of the auxiliary tool, which are designed to be free of reinforcement tube contact and/or primary tool contact, do not have to be manufactured to the same quality as the cover surfaces of the auxiliary tools that make contact with the reinforcement tube and/or primary tool. Furthermore, with a reinforcement tube contact-free and/or primary tool contact-free arrangement of the cover surfaces of the auxiliary tool, cost-intensive surface treatments for reducing the surface roughness of these cover surfaces can be dispensed with or their use can at least be reduced, in particular to reduce settling phenomena. Therefore, a particularly cost-effective modular forming tool can be achieved by the reinforcement tube contact-free and/or primary tool contact-free arrangement of the cover surface or surfaces.
Advantageously, the outer dimension of the circumferential surface of at least one auxiliary tool essentially corresponds to the nominal dimension of the outer sheath surface of a reinforcing tube. Correspondence with the “essentially nominal dimension” is present in particular if the outer dimension of the circumferential surface of the decisive auxiliary tool and the outer dimension of the outer sheath surface of the reinforcing tube have the same dimensions except for the tolerance class. Therefore, in particular, the governing outer sheath surface of the reinforcing tube and the governing dimension of the circumferential surface of the auxiliary tool are such that they correspond to the same nominal dimension, so that they differ only with respect to their tolerance class. For example, the decisive outer sheath surface of the reinforcing tube can have a tolerance class of m to u and the circumferential surface of an auxiliary tool can have a tolerance class of b to h. In particular, DIN ISO 286-1 can be decisive for the tolerance class. By designing the circumferential surface of at least one auxiliary tool in such a way that it essentially corresponds to the nominal dimension of the outer circumferential surface of a reinforcing tube, it is possible to save expensive storage costs, because the variety of parts to be kept in stock can be greatly reduced as a result. It is particularly preferred if the outer dimension of the circumferential surface of all auxiliary tools substantially corresponds to the nominal dimension of the outer sheath surface of at least one other reinforcing tube of the modular forming tool. In other words, this may mean that the outer dimension of the circumferential surfaces of each auxiliary tool corresponds to at least the outer dimension of a reinforcing tube of the modular forming tool, except for the tolerance class.
Expediently, the forming tool has a plurality of reinforcing tubes, wherein the reinforcing tubes radially surround the primary tool, in particular all primary tools. This makes it possible to achieve a simple modular design of the modular forming tool, in which costs can be saved because the subassembly of reinforcement tubes and the primary tool or tools can be pre-assembled as a result. In addition, the contact surface or surfaces between the reinforcing tubes and the primary tool or primary tools can also provide high modular damping of the entire forming tool, resulting in particularly good vibration characteristics. The term “surround” in the radial direction means that all the primary tools, viewed in the radial direction, have at least one reinforcing tube which surrounds the primary tool or all the primary tools.
It is expedient that at least one end surface of a primary tool, in particular of each primary tool, is flush with a reinforcing tube in the longitudinal direction, this reinforcing tube advantageously surrounding the primary tool. The flush closure of the primary tool with a reinforcing tube, advantageously with all reinforcing tubes that surround the primary tool, can save costs, because this effectively allows preassembly to take place. This prefabrication therefore means that certain submodules can already be prefabricated, so that costs can be saved. Flush closure is understood to mean that in particular an end surface of the primary tool and a surface bounding the reinforcing tube lie in one plane in the longitudinal direction. Advantageously, this plane is designed in such a way that it has a normal which is at least essentially parallel to the direction of longitudinal extension. In this way, transverse forces acting perpendicular to the longitudinal direction can be avoided. In other words, flush closure can therefore be understood to mean that at least one distal end of a primary tool and of a, in particular surrounding, reinforcing tube lie in one plane in the longitudinal extension direction. Advantageously, all the reinforcing tubes surrounding the primary tool are flush with this surrounded primary tool in the longitudinal direction.
In an advantageous embodiment, at least one end surface of a primary tool, in particular of each primary tool, is flush in the longitudinal direction with all reinforcing tubes surrounding the respective primary tool. This makes it possible to achieve simple prefabrication or preassembly, so that assembly costs can be further reduced.
Preferably, the reinforcement tubes and/or the auxiliary tools are made of rolling bearing steel. By designing the reinforcement tubes and/or the auxiliary tools from rolling bearing steel, a particularly mechanically resilient design of the modular forming tool can be achieved so that even high forming forces can be safely applied to the workpiece without the risk of mechanical failure of the modular forming tool.
Expediently, the reinforcing tubes are formed in such a way that all reinforcing tubes having substantially equal outer dimensions in the radial direction also have substantially equal inner dimension in the radial direction. In other words, this may mean that all reinforcing tubes having substantially the same dimensioned inner sheath surfaces also have substantially the same dimensioned outer sheath surfaces. A “substantially equal” or “substantially the same” dimensioning exists in particular if the relevant dimensions differ from each other only by a maximum of +/−0.08 mm, preferably by a maximum of +/−0.05 mm, particularly preferably by a maximum of +/−0.02 mm, and especially preferably by a maximum of +/−0.01 mm. For example, the reinforcing tubes, which have a cylindrical inner sheath surface and a cylindrical outer sheath surface, can be designed in such a way that the reinforcing tubes with the same diameter of the inner sheath surface also have the same diameter with regard to the outer sheath surface. This geometric classification of the reinforcing tubes can further increase the modularization of the modular forming tool so that costs can be saved. However, the length of these reinforcement tubes in the longitudinal direction can be different despite the same inner and outer dimensions. Advantageously, however, the lengths of these reinforcement tubes in the longitudinal direction are also the same.
Advantageously, at least the inner reinforcing tubes, preferably all reinforcing tubes, are designed in such a way that the ratio of the inner dimensions in the radial direction to the outer dimension in the radial direction is in a range from 0.7 to 0.98, preferably in a range from 0.8 to 0.97 and particularly preferably in a range from 0.85 to 0.95. The inner reinforcing tubes are in particular the reinforcing tubes which, in particular in an installed or grouted state, contact another reinforcing tube at their outer circumferential surface. Therefore, in particular, the reinforcing tubes whose outer sheath surface contacts the tool holder are not internal reinforcing tubes. Alternatively or additionally preferred, only those reinforcing tubes are not internal reinforcing tubes which have the largest dimension in the radial direction. With a ratio of the inner dimension in the radial direction to the outer dimension in the radial direction in a range from 0.7 to 0.98, a particularly easy-to-manufacture geometry of the reinforcing tubes can be achieved, so that costs can be saved. A ratio of 0.8 to 0.97 results in reinforcement tubes with particularly high mechanical strength. The ratio is determined on the basis of the maximum external dimensions of the reinforcement tube in the radial direction to the minimum internal dimensions of the reinforcement tube in the radial direction.
More expediently, the modular forming tool is a punch and/or a die. In other words, the modular forming tool can be designed both as a punch and/or be designed as a die. A die in the sense of the present invention is a forming tool which is not moved during the forming process, but in particular is arranged stationary in relation to the machine tool. A punch in the sense of the invention, on the other hand, is a forming tool which is moved in relation to the machine tool and/or in relation to the die during the forming process.
Preferably, the modular forming tool is bounded in the longitudinal extension direction by a screw plug. In other words, this can mean that, viewed in the longitudinal direction, at least one screw plug forms a distal end section of the modular forming tool in the longitudinal direction. By using a screw plug, a particularly simple and secure fixing of the modular components of the forming tool can be achieved. Advantageously, the tool holder has an internal thread into which the screw plug is screwed or can be screwed.
It is expedient for the screw plug to have a threaded section, the threaded section having a nominal diameter which is greater than the maximum dimension of all the reinforcing tubes of the forming tool in the radial direction. Due to this particularly large design of the threaded section of the screw plug, a particularly high mechanical load capacity can be achieved. The nominal diameter of the threaded section is in particular the outer diameter of the thread. Particularly preferably, the nominal diameter of the thread is 1.1 to 1.4 times the maximum dimension of all the reinforcing tubes of the forming tool in the radial direction. This makes it possible to achieve both a mechanically loadable and compact design of the thread section. In this context, the decisive maximum dimension of all reinforcement tubes of the forming tool in radial direction is the largest possible dimension in radial direction of the reinforcement tubes of the decisive modular forming tool. In other words, the maximum dimension of all the reinforcement tubes of the forming tool in the radial direction may be the maximum outer diameter of the largest reinforcement tube. The relevant modular forming tool is in particular the die or the punch on which the screw plug is mounted.
Another aspect of the invention may relate to a modular forming tool set, which may comprise two modular forming tools according to the above-described embodiments, wherein the one modular forming tool is a punch and wherein the second modular forming tool is a die.
A likewise further aspect of the invention relates to a method for producing substantially rotationally symmetrical parts, in particular screws and/or bolts, comprising the steps: Providing a workpiece blank and forming the workpiece blank by a modular forming tool as described above and/or below. The forming of the workpiece blank is thereby effected by contact of the workpiece blank with the work-piece machining surface(s) of the primary tool(s) of the modular forming tool. The forming of the workpiece blank into a substantially rotationally symmetrical part may thereby be accomplished by only one forming step. Alternatively preferably, however, several forming steps may be performed in the manufacturing process. In this case, it is preferred if each of these forming steps is carried out using a modular forming tool according to the invention. After or before the forming of the workpiece blank, further processing steps may also be included in the manufacturing process, such as recutting and/or rolling of a thread and/or the application of lubricants, in order to simplify the forming of the workpiece blank.

Further advantages and features of the invention will be apparent from the following description in relation to the figures. Showing:

FIG. 1 a section through a modular forming tool in the form of a die;

FIG. 2 a section through a modular forming tool in the form of a punch and

FIG. 3 a modular forming tool set.

FIG. 1 shows a modular forming tool 1, which is a die 3. The forming tool 1 extends along the longitudinal direction L, wherein the radial direction R extends radially away from this longitudinal direction L. The forming tool 1 comprises a tool holder 60 as well as numerous primary tools 10 and reinforcing tubes 30. The forming tool 1 comprises a tool holder 60 as well as numerous primary tools 10 and reinforcing tubes 30. In addition, the forming tool 1 also has two auxiliary tools 50. One of the auxiliary tools 50 at least partially forms a distal end of the forming tool 1 along the longitudinal extension direction L by one of its cover surfaces 56. The tool holder 60 has an inner peripheral surface which forms an interference fit with the outer sheath surfaces 34 of the outer reinforcing tubes 30. In contrast, the auxiliary tools 50 and their circumferential surface 54 have clearance fits with respect to the tool holder 60 and the inner sheath surface of the tool holder 60, respectively. The reinforcing tubes 30 are each mechanically fixed in place via their inner sheath surface 32 and via the outer sheath surface 34 by means of an interference fit, so that this interference fit counteracts a displacement in the direction of longitudinal extension L. The reinforcement tubes 30 closest to the longitudinal direction of extension L in the radial direction R or the central reinforcement tubes 30 each at least partially enclose an auxiliary tool 50. These auxiliary tools 50 are pressed into the inner sheath surface 32 of the closest central reinforcement tube 30 via their sheath surface 14. Through this, a fixation of each primary tool 10 in radial direction R and at least partially also in longitudinal extension direction L can be achieved. The end surfaces 16 of the primary tools 10 each form the distal ends of the primary tools 10 in positive and/or negative longitudinal extension direction L. In an assembled state, as shown in FIG. 1 , these end surfaces 16 can either be arranged in a contact-free manner or can be arranged in a contacting manner with an auxiliary tool 50 and/or a further end surface 16 of a primary tool 10, the contact-free end surfaces 16 forming in particular a distal end of the forming tool 1. Radially inward in radial direction R, the primary tools 10 each form a workpiece machining surface 12. The primary tool 10 can in particular be formed from a hard metal, while the reinforcing tubes 30 and/or the auxiliary tools 50 can be formed from rolling bearing steel. As can be seen from FIG. 1 , the primary tools 10 and the reinforcing tubes 30 each form a press connection to one another via the contacting sheath surfaces 14 of the primary tools 10 and the inner sheath surfaces 32 of the reinforcing tubes. The auxiliary tools 50, on the other hand, do not have any interference fit, so that they are not held in any way by an interference fit in the longitudinal direction of extension L. Rather, there is a clearance fit between the circumferential surface 54 of the auxiliary tool 50 and the tool holder 60.
FIG. 2 shows a modular forming tool 1 in the form of a punch 2. The punch 2 has a primary tool 10 which is enclosed by the reinforcing tubes 30. The reinforcing tubes 30 each have an inner sheath surface 32 in the radial direction R towards the inside, which forms an interference fit with the adjacent or nearest surface. In addition to the reinforcing tubes 30 and the primary tool 10, the punch 2 also has a number of auxiliary tools 50, which serve to provide positive support for the primary tools 10 and the reinforcing tubes 30 in the direction of the longitudinal extension direction L. These auxiliary tools 50 each have a circumferential surface 54 which delimit the respective auxiliary tool 50 in radial direction R. These circulating surfaces 54 each have a clearance fit with their outer surrounding or contact partner in the radial direction R. In addition to the primary tools 10, the auxiliary tools 50 and the reinforcing tubes 30, the punch 2 also has a screw plug 70 which forms a distal end of the punch 2 along the longitudinal direction of extension L.
The screw plug 70 has a threaded section 72 that has a nominal diameter that is greater than the maximum dimension of all of the reinforcing tubes 30 of the punch 2.
FIG. 3 shows a forming tool set comprising a forming tool 1 in the form of a punch 2 and a forming tool 1 in the form of a die 3. The punch 2 and die 3 shown in FIG. 3 may correspond to the punch 2 in FIG. 2 and the die 3 in FIG. 1 , respectively. During a forming process of a workpiece to be formed by means of the forming tool set, the punch 2 can be moved in relation to the die 3 along the longitudinal extension direction L in order to achieve forming of the workpiece. For this purpose, in particular, the free space F inside the punch 2 can be used to form the head of a bolt or screw. In other words, by displacing part of the material of the workpiece within the free space F and/or into the free space F, the head of the workpiece, in particular that of a screw and/or a bolt, can be created. The primary tools 10 are also used to achieve the configuration of the workpiece, such as a thread and/or a head and/or a shank of a substantially rotationally symmetrical component. In this respect, the auxiliary tools 50 are each arranged over their circumferential surface 54 in such a way that these have a clearance fit in the radial direction R.

LIST OF REFERENCE SIGNS

1—Forming tool
2—Punch
3—Die
10—Primary tool
12—Workpiece machining surface
14—Sheath surface
16—Face
30—Reinforcing tube
32—Inner surface
34—Outer sheath surface
50—Auxiliary tool
54—Circulation area
56—Cover surface
60—Tool holder
70—Screw plug
72—Threaded section of the screw plug
F—Free space
L—Longitudinal direction of extension
R—Radial direction

Claims

1. Modular forming tool (1), in particular press tool,

comprising at least one primary tool (10), in particular a core,

at least one reinforcement tube (30) and

at least one auxiliary tool (50),

wherein the forming tool (1) extends along a longitudinal extension direction (L),

wherein the primary tool (10) has a workpiece machining surface (12), a sheath surface (14), and two end surfaces (16),

wherein the workpiece machining surface (12) contacts or is adapted to contact a workpiece,

wherein the sheath surface (14) bounds the primary tool (10) in a radial direction

(R),

wherein the end surfaces (16) delimit the primary tool (10) in the longitudinal extension direction (L),

wherein the reinforcing tube (30) has an inner sheath surface (32) and an outer sheath surface (34),

wherein the primary tool (10) is pressed into the reinforcing tube (30) indirectly and/or directly via the sheath surface (14), so that the primary tool (10) is secured relative to the reinforcing tube (30) in the radial direction (R),

wherein the inner sheath surface (32) and the outer sheath surface (34) each have an interference fit,

wherein the auxiliary tool (50) is limited in the longitudinal extension direction (L) by cover surfaces (56),

wherein the auxiliary tool (50) is bounded outwardly in the radial direction (R) by a circumferential surface (54),

wherein the circumferential surface (54) has a clearance fit in the radial direction (R), and

wherein the modular forming tool (1) is a punch.

2. Modular forming tool (1) according to claim 1,

wherein the forming tool (1) has an outer tool holder (60),

wherein all of the primary tools (10), reinforcing tubes (30) and auxiliary tools (50) of the forming tool (1) extend at least partially within the tool holder (60).

3. Modular forming tool (1) according to claim 1,

wherein at least one cover surface (56) of an auxiliary tool (50) directly contacts a reinforcing tube (30) and/or a primary tool (10).

4. Modular forming tool (1) according to claim 1,

wherein at least one cover surface (56) of an auxiliary tool (50) is free of reinforcement tube contact and/or primary tool contact.

5. Modular forming tool (1) according to claim 1,

wherein the outer dimension of the circumferential surface (54) of at least one auxiliary tool (50) substantially corresponds to the nominal dimension of the outer sheath surface (34) of a reinforcing tube (30).

6. Modular forming tool (1) according to claim 1,

wherein the forming tool (1) comprises a plurality of reinforcing tubes (30),

wherein the reinforcing tubes (30) surround the primary tool (10), in particular all primary tools (10), in the radial direction (R).

7. Modular forming tool (1) according to claim 1,

wherein at least one end surface (16) of a primary tool (10), in particular of each primary tool (10), terminates flush in the longitudinal extension direction (L) with a reinforcing tube (30).

8. Modular forming tool (1) according to claim 1,

wherein at least one end surface (16) of a primary tool (10), in particular of each primary tool (10), terminates flush in the longitudinal extension direction (L) with all reinforcing tube(s) (30) surrounding the respective primary tool (10).

9. Modular forming tool (1) according to claim 1,

wherein the reinforcing tubes (30) and/or the auxiliary tools (50) are made of rolling bearing steel.

10. Modular forming tool (1) according to claim 1,

wherein the reinforcing tubes (30) are formed such that all reinforcing tubes (30) having substantially the same outer dimension in radial direction (R) also have substantially the same inner dimension in radial direction (R).

11. Modular forming tool (1) according to claim 1,

wherein at least the inner reinforcing tubes (30), preferably all reinforcing tubes (30), are formed such that the ratio of the inner dimension in radial direction (R) to the outer dimension in radial direction (R) is in a range of 0.7 to 0.98, preferably in a range of 0.8 to 0.97 and particularly preferably in a range of 0.85 to 0.95.

12. Modular forming tool (1) according to claim 1,

wherein the modular forming tool (1) is limited in longitudinal extension direction (L) by a screw plug (70).

13. Modular forming tool (1) according to claim 1,

wherein the screw plug (70) has a threaded section (72),

wherein the threaded section (72) has a nominal diameter that is between an inner

dimension and an outer dimension of a reinforcing tube (30) of the forming tool (1).

14. Modular forming tool set comprising two modular forming tools (1) according to claim 1,

wherein the one modular forming tool is a punch (2), and

wherein the second modular forming tool (1) is a die (3).

15. Method of manufacturing substantially rotationally symmetrical parts comprising the steps:

Provision of a workpiece blank and

Forming the workpiece blank by a modular forming tool (1) according to claim 1.