CN112165997B

CN112165997B - Bending mould with spacer elements

Info

Publication number: CN112165997B
Application number: CN201980033286.4A
Authority: CN
Inventors: 哈拉尔德·芬茨尔; 阿尔弗雷德·哈泽尔博克; 海因茨·洛伊穆勒; 乔瓦尼·维多托
Original assignee: Trumpf Maschinen Austria GmbH and Co KG
Current assignee: Trumpf Maschinen Austria GmbH and Co KG
Priority date: 2018-06-27
Filing date: 2019-05-29
Publication date: 2022-09-27
Anticipated expiration: 2039-05-29
Also published as: WO2020000003A1; CN112165997A; AT521173B1; EP3814032A1; AT521173A4

Abstract

The invention relates to a crank-like bending die (1) for a bending machine, comprising a die body (3) having at least one die shank (4) for accommodating the bending die (1) at least partially in an accommodating shaft provided for this purpose, and the die body (3) having a die center of gravity lying outside a vertical plane of symmetry of the accommodating shaft. At least one movement element (8) for moving the bending tool (1) in the longitudinal direction (22) of the bending machine and for receiving in a recess is provided on the tool shank (4), said movement element being formed on the tool shank (4) such that it protrudes at least on one side relative to the respective tool shank surface (7). At least one spacer element (2) is also provided for exerting a supporting force (23) opposing the tilting moment caused by the deviation of the center of gravity of the mold from the plane of symmetry in the transverse direction (21). At least one spacer element (2) comprises at least one rolling element (25) which is mounted with a preload force (24) and is mounted on the mold body (3) such that it can move at least in the direction of the preload force (24) or at least partially within the mold body and is arranged at least partially in a protruding manner relative to a surface of the mold body (3) adjacent to the at least one rolling element (25).

Description

Bending mould with spacer elements

The invention relates to a crank-like bending die for a bending machine, in particular a bending machine, comprising a spacer element prestressed with a prestress force to compensate for tilting moments.

A bending die used as an upper die for deforming a plate member in a bending machine may generally have a die body including a complicated geometry. In this case, the mold body can be bent in a crank-like manner, i.e. at least simply angled away from the bending direction. In such a mold geometry, the center of gravity of the mold is usually no longer located in the vertical plane of symmetry of the mold receptacle or mold shank, but rather is offset laterally in the transverse direction.

The lateral offset of the center of gravity of the mold from the plane of symmetry causes a tilting moment of the cranked mold on and/or in the mold receptacle. When changing the bending tool, the tilting moment can lead to a higher friction of the bending tool and/or the tool holder on the contact surface until the bending tool is clamped in the tool holder.

In order to prevent damage to the mould, it is proposed in WO2014/007640a1 to mount rigidly arranged rollers in the mould shank or on the mould shoulder of the bending mould, which rollers should simplify the further movement of the bending mould in the receiving shaft. The rigidly mounted rollers are intended to be rigid in order to be able to support the bending tool on the tool receptacle.

The future always requires lower manufacturing tolerances and/or very high fitting accuracy of the mold receptacle and the mold body. This means that a support and/or movement of the mold shank in the receiving shaft of the mold receiver is required which is as play-free as possible. However, the systems known from the prior art, such as the system disclosed in WO2014/007640a1, have only limited practical use, since they have the disadvantage that the rollers can be partially severely worn and can be damaged by the generally curved mold being clamped in the mold receptacle. Furthermore, the automatic replacement process of the bending mould is difficult to carry out by means of external robots and/or robots.

The object of the present invention is to overcome the disadvantages of the prior art and to provide a bent-out crank-like bending die which reduces wear on the bending die and/or the die receiving part. Another object of the present invention is to reduce the resistance of the bending die to movement in the die receiving portion and to prevent the bending die from being clamped in or on the die receiving portion. Furthermore, the bending die according to the invention can be applied on both sides, i.e. substantially independently of the insertion direction.

This object is achieved by a bending mould according to the invention.

A bending die bent into a crank shape for a bending machine, in particular a bending machine, according to the invention comprises a die body, at least one moving part and at least one spacer element. The mold body has at least one mold shank for at least partially receiving the bending mold in a bending direction in a receiving pocket of the mold receptacle provided for this purpose, wherein the mold body has a mold head connected to the mold shank in the bending direction, the mold head having a mold center of gravity outside a vertical plane of symmetry of the receiving pocket and/or the mold shank and having a mold shoulder in a transverse direction at least on one side. In order to move the bending tool in the longitudinal direction of the bending machine for receiving in the recess, at least one moving part is formed on the tool shank, which is formed on the tool shank in a projecting manner at least on one side relative to the respective tool shank surface. At least one spacer element is used to exert a supporting force on at least one surface of the mold receptacle opposite to a tilting moment caused by a deviation of the center of gravity of the mold from the plane of symmetry in the transverse direction. At least one spacer element comprises at least one rolling element mounted with a pretensioning force, which is mounted on or at least partially within the mold body so as to be movable at least in the direction of the pretensioning force and is arranged at least partially in a protruding manner relative to a surface of the mold body adjacent to the at least one rolling element.

In brief, the tilting moment acts about the longitudinal axis of the bending tool or tool holder and causes the bending tool to press onto at least one contact point. By forming at least one spacer element by means of at least one rolling body which is directly or indirectly prestressed with a prestressing force, the at least one spacer element can compensate tilting moments by transmitting supporting forces from the bending tool to the tool receptacle. This reduces the friction between the receiving shaft and the mold shank and/or between the underside of the mold receptacle and the mold shoulder or the mold shoulder plane during the movement of the bending mold in the mold receptacle. The reduction in friction results in reduced wear of the contact surfaces. In addition, clamping of the bending tool on and/or in the tool holder can be avoided.

Furthermore, the at least one rolling element is mounted or prestressed so as to be movable in the direction of the prestressing force, so that the bending tool shank can be simply introduced into a receiving shaft of the tool holder provided for this purpose. This allows a relatively simple and rapid exchange of the bending tool, wherein the compensation of the tilting moment increases the reliability and reduces wear.

It can furthermore be expedient for the at least one rolling element to be arranged on and/or at least partially in the mold body in order to exert a supporting force on the inside of the receiving shaft perpendicular to the bending direction or the transverse direction and/or on the underside of the mold receptacle in the bending direction.

The movable mounting or pretensioning of the at least one rolling element in the direction of the pretensioning force thus causes an automatic coupling of the rolling element with the corresponding surface of the mold receptacle. This is particularly advantageous when automatically changing bending moulds, since no additional mechanical handling robots or the like are required and at least one spacer element or rolling body can be retracted at least temporarily completely behind the surface of the mould body.

The optimum required supporting or prestressing force and the required space on and/or in the mould body can also be achieved by suitable positioning of the at least one spacer element on the mould body. For example, a relatively short lever arm when the spacer element is positioned on or in the mold shank requires a higher pretension force to apply the required supporting force to the inside of the receiving shaft than when the spacer element is arranged on or in the mold shoulder, since a larger lever arm may be used when the spacer element is arranged on or in the mold shoulder.

It is also possible to provide more than one spacer element on the mould body, in particular in the longitudinal direction. It is also conceivable for one spacer element to be used to exert a part of the supporting force on the die shank relative to the inner surface of the receiving shaft and for the other spacer element to be used to exert a part of the supporting force on the die head in the direction of the underside of the die receiving portion. In this way, the required partial pretensioning force can be selected relatively low, so that the introduction into the bending tool is particularly simple.

At least one of the spacer elements can also have an adjusting device for adjusting the pretensioning force.

The advantage of the adjusting device is that different mold geometries and/or mold weights and the supporting or prestressing forces required in connection therewith can be matched in a simple manner. This can be used, for example, after maintenance of the bending mould to match the supporting force to the changing position of the centre of gravity of the mould.

Such an adjusting device can be formed, for example, by a spring element, preferably a helical spring, which can be acted upon by a predefinable spring force or pretension by means of a settable spring travel. The adjusting device can also be formed, for example, by a settable support mechanism of a spring element, for example, a bent rod, and comprises an adjusting screw. The adjusting device is advantageously accessible from the outside, whereby the pretensioning force can be adapted or set in extreme cases even when the bending tool is accommodated in the tool holder.

Furthermore, the spacer element can comprise at least two rolling bodies, which are preferably arranged side by side in the rolling body receptacles.

In this way, the supporting forces can be better transmitted at a plurality of contact points, as a result of which a lower local surface contact of the respective rolling bodies with the surface of the tool holder can be achieved. This reduces the resistance or force consumption when introducing the bending tool into the receiving shaft and reduces wear.

It is also advantageous if the at least one spacer element comprises a rolling element receptacle and at least one limiting element, which is designed to be movably connected to the mold body by means of at least one fastening element in the direction of the prestressing force for limiting a deflection of the rolling element receptacle or of the rolling elements.

In this case, at least one rolling element is rotatably mounted in a rolling element receptacle, wherein a limiting element can be arranged on the side and in the interior of the rolling element receptacle, so that the movement of the rolling element receptacle and the rolling element can be limited. Such a stop element is, for example, movably connected to and/or in the mold body or in the spacer element housing, whereby the respective spacer element is fixed against damage, for example, due to falling off and/or dropping off. Furthermore, such a stop element serves to prevent the spacer element or the rolling body from protruding beyond a predefinable height above the surface of the mold body, which is advantageous in particular for simple introduction.

The stop element can be formed, for example, by a groove or a correspondingly configured extension of the rolling element receptacle to at least partially receive the fastening element. In the simplest case, the fastening element can be a screw, the screw head serving as an atraumatic part and its thread and/or shank or unthreaded part serving as a guide and stop for the limiting element in the pretensioning direction.

According to a further development, at least one spacer element can be arranged in a spacer element housing at least for accommodating the rolling element receptacles and the at least one limiting element and for supporting the adjusting device relative to the rolling element receptacles.

A spacer element of this construction can be regarded as a functional unit which can be produced relatively simply and also enables the adjusting device to be supported in the spacer element housing and not necessarily on the mould body. In this way, a "add-on element" can be provided in a simple manner, which can be mounted relatively simply on and/or in an existing mold body and/or can be exchanged.

It is also expedient for at least one spacer element to be arranged outside the mould head in order to support the bending mould on the underside of the mould receptacle.

This arrangement is advantageous because simple accessibility from the outside is achieved, for example for setting the pretensioning force. Furthermore, a relatively large lever arm between the rolling body and the plane of symmetry is used, as a result of which the required supporting or prestressing force can be selected relatively low.

The spacer element can furthermore be designed as a bent rod, such that the at least one rolling element is arranged on a free end of the bent rod and a fastening end of the bent rod is fastened in the mold body, preferably in the mold head, perpendicularly to and/or in the bending direction.

The bending beam has a predefinable flexibility in at least one direction, whereby the pretensioning force can be set essentially by the geometry of the bending beam, in particular the partial cross section of the bending beam, the diameter of the rolling bodies and the available bending length. The curved bars can be manufactured relatively simply and cost-effectively. The bending rod can be accommodated in a receiving opening provided for this purpose in the mold body, which can also be configured, for example, as a bore. The receiving opening advantageously does not extend through the mold body and has a larger diameter than the bending rod or the rolling body in order to enable a movement of the spacer element at least in the direction of the pretensioning force. The fixed end is advantageously screwed into the mold body and the at least one rolling element is rotatably fixed on the free end.

Furthermore, at least one rolling element can be arranged at least partially protruding with respect to the upper side of the die shoulder and can be fixed to the die head perpendicularly to the bending direction by means of a fixing end of the bending rod in order to exert a supporting force in the bending direction with respect to the die receptacle.

In this way, a particularly large bending length of the bending rod and a rigidity or flexibility that can be set or predetermined in a simple manner can be achieved. The rolling bodies may be arranged such that they project onto the surface of the mold shoulder. Preferably, the free ends and/or the rolling bodies are flush with the surface of the die head adjoining in the longitudinal direction in the transverse direction, or even set back behind the surface of the die head adjoining in the longitudinal direction. Thereby avoiding elements protruding onto the mould body, which elements would hamper the operation of the bending mould. This is particularly useful for using an automated mold changing device.

According to a particular embodiment, it is possible that the bending rod comprises at least one thread section for accommodating the bending rod in the die head and/or the die shank, a bending section having a predefinable bending length, and a rolling element section, and the adjusting device for setting the preload by adjusting the predefinable support distance between the thread section and the rolling element section is arranged to at least partially support the bending section.

The threaded section is provided for receiving a fixed end in the die body, while a rolling body section for receiving at least one rolling body is arranged on the free end of the bending rod. The bending length for applying and/or setting the pretension extends between the sections along the bending section. The adjusting device of this embodiment preferably comprises an adjusting screw and/or a spindle drive, which is rotatably supported in the mold body. The adjusting device can also have a support element which moves parallel to the bending bar and interacts with an adjusting screw or a spindle drive. In this way, a two-point support for the bending bar can be formed by means of the adjusting device. The free bending length of the bending rod can be set relatively simply by setting the support distance to the threaded section, as a result of which the pretensioning force can be set. The support element can be, for example, a sleeve or a C-or V-shaped configuration in order to support the bending rod at least on one side, preferably in a surrounding manner.

According to a preferred refinement, the bending rod can be designed as a beam-waist bending rod, wherein the bending section is designed as a first beam waist section and the rolling body section is designed as a second beam waist section, and at least one beam waist section diameter of the first beam waist section and/or of the second beam waist section is smaller than the thread section diameter.

It has been found that the reduction of the cross section of the bent rod from the threaded section towards the free end, preferably as two waisted sections, results in an increased durable strength of the bent rod. Furthermore, a simpler design of the bending rod is achieved by the smaller diameter of the bending section and/or of the rolling element section. A smaller beam waist section diameter can also be used to optimize the stiffness or pretension of the bending beam in a relatively simple manner.

In particular, the beam waist section diameter of the first beam waist section or of the curved section may also not be continuous, i.e. not formed according to a mathematical function. This can be used by the technician to set different local beam waist section diameters, which optimize the stiffness requirements in terms of the necessary pretension and/or durability along the bending beam.

In particular, it may be advantageous if the adjusting device for adjusting the predefinable support distance comprises a preferably sleeve-shaped support element which at least partially surrounds the bending section.

By this measure, a two-point bearing of the bending lever can be formed relatively simply and firmly on the free end of the adjusting device and on the supporting element. The at least partially surrounding and in particular sleeve-shaped support element prevents a local bending of the bending rod on the support element in the direction of the pretensioning force to be applied, as a result of which a better and more stable bearing is achieved.

It is also possible to configure the at least two moving parts side by side in the longitudinal direction as sliding elements or preferably as rolling elements.

This measure reduces the local friction and/or the local surface pressure on the respective moving part, as a result of which the wear risk and the inclination of the bending tool to wedge in the tool holder can be reduced. The sliding element is advantageously made of a material with a low coefficient of friction with respect to the mold receptacle and high mechanical strength. Preferably, polymers are used, such as PTFE, PEEK, PPSU, PAEK, etc., as they may also have high solvent and/or lubricant resistance. In particular, rolling elements similar to rolling elements, for example rollers which can be designed as ball bearings, are advantageously used. The rolling elements have the advantage of very low rolling friction and high mechanical stability.

Furthermore, at least two moving parts can be formed on opposite sides of the mold stem in the transverse direction, preferably symmetrically opposite.

This results in a better load relief of the weight of the bending tool in the tool receptacle and a significant reduction in the wear of the moving parts can be achieved, in particular in combination with the at least one spacer element for compensating tilting moments.

In a special embodiment, the at least one movement element can be configured integrally with the mold shank as a forward extension.

This movement serves as a sliding element and is configured as an integral forward extension of the stem part of the mould. These sliding elements can be considered in the case of the manufacture or machining of the die shank and can therefore be produced simply. It is particularly advantageous here if at least the moving part designed as the extension of the mold shaft is coated and/or varnished with a surface layer having a low coefficient of friction, for example PTFE. Carbon-based low-friction layers, such as amorphous carbon (DLC), are particularly conceivable as surface layers, as a result of which the friction of the at least one front extension can be effectively reduced.

All embodiments according to the invention also have the effect that the mold shank or the bending mold can be introduced into the mold receptacle on both sides, since the tilting moment can be compensated by the at least one spacer element substantially without changes having to be made on the mold receptacle.

In order to temporarily fix the bending tool in the tool receptacle, a tensioning or clamping system is furthermore usually used, which clamps the bending tool on the tool shank in one or more clamping grooves provided for this purpose. In the best case, the upper side of the die shank is pressed against the receiving shaft and the die shoulder, which is always present, is pressed against the lower side of the die receptacle. According to the invention, the at least one spacer element is retracted after the corresponding surface of the mould body during clamping or tensioning of the mould, whereby the clamping process can be carried out unhindered and incorrect "tensioning" of the bending mould can be effectively avoided. Furthermore, damage to the tensioning or clamping system, the mold receptacle and/or the bending mold can be avoided.

The invention can also be transferred to bending moulds in which the centre of gravity of the mould is in the plane of symmetry. The previously described embodiments of the cranked bending tool according to the invention with spacer elements constructed according to the invention can also be used here to compensate tilting moments in the transverse direction and/or in the longitudinal direction in a non-cranked bending tool or in a cranked bending tool in which the center of gravity of the tool lies in the plane of symmetry. Such tilting moments of the bending mould can arise as a result of the bending mould moving in the longitudinal direction and causing a vibrating movement and/or clamping. The spacer elements can be arranged on the mold body on both sides in the transverse direction, for example, in order to minimize a vibration movement and/or clamping during the introduction into the mold receptacle, as a result of which the entry speed is increased and the installation time can be reduced.

According to an advantageous development, at least one of the moving parts can comprise a roll pin which is rotatably supported in the die shank relative to the die body by means of at least one rotary support element. The crank-like bending tool used as the upper tool can thus be moved in a particularly stable manner, in particular easily by passing through and without clamping, relative to its rail-like tool holder and positioned as required when the clamping device is inactive.

It can be particularly advantageous if the at least one rotary bearing element is formed by at least one plain bearing element or rolling bearing element which is held in a receiving bore of the die shank, in particular pressed in. A stable and at the same time as economical construction of the bending mould is thereby achieved.

Furthermore, it is possible to design the at least one rolling pin as one piece and at the same time penetrate the die shank with the interposition of the at least one rotary bearing element, such that the mutually opposite end sections thereof each project relative to the mutually opposite die shank surfaces. The one-piece roll pin provides a high degree of stability, while the at least one rotary bearing element ensures a high degree of bearing stability. In addition, a reliable sliding movement of the bending tool relative to the tool holder and/or relative to the guide rail of the bending machine can be guided in this way.

It is also possible for at least one spacer element to comprise a rolling element receptacle in which at least one rolling element in the form of a cylindrical roller body is rotatably mounted. This provides a spacer element which is particularly robust and at the same time can be realized in a cost-effective manner. In particular, a functionally combined sliding and rolling element is thereby formed, the "slider" of which serves as a receptacle for at least one rolling element.

It is also advantageous if the at least one cylindrical roller body is held in at least one bore formed in the rolling element receptacles, wherein the longitudinal axis of the at least one bore is oriented such that a portion of the outer surface of the cylindrical roller body protrudes relative to the outer surface of the rolling element receptacles. This achieves a wear-free and at the same time high-strength rotational bearing of the cylindrical roller body. Furthermore, a highly stable and mechanically reliable rotational mounting of at least one rolling element embodied as a roller body can be achieved.

According to one refinement, the rolling element receptacles can be accommodated in part in a recess in at least one mold shoulder or at least one mold shank surface and can be spring-mounted relative to the recess by applying a prestressing force. A spacer element is thus provided which on the one hand enables an easy movement of the bent-out crank-like bending tool when the clamping device is inactive and on the other hand ensures a precise and planned orientation relative to the tool holder when the clamping device is active on or in the tool holder. In addition, this prevents point-like load peaks or damage risks of the bending tool and/or the tool holder.

It can also be expedient for the rolling element receptacle to have a thrust ramp in at least one of its longitudinal end sections or a crowned surface at least in its center section. The reliability and ease of passage of the bending die replacement process and/or the bending die positioning process can thereby be further improved.

It is also possible for at least one cylindrical roller body to be composed of metal and for the rolling element receptacles to be composed of a different material, in particular of plastic. Good long-term stability of the roller body can thereby be achieved. This also makes it possible to achieve wear-free or friction-reducing rotational mounting of the roller body.

Furthermore, the pretensioning force acting on the rolling element receptacle and the at least one rolling element can be provided by at least two spring elements spaced apart from each other in the longitudinal direction, preferably acting on end sections of the rolling element receptacle. This makes it possible to support the rolling element receptacles as reliably as possible without tilting and with a reliable function.

Finally, it may also be expedient for at least one of the rolling bodies to have a rolling outer surface which increases friction relative to the metal surface, in particular consisting of plastic, preferably elastomeric plastic. This makes it possible to reliably rotate or roll the rolling bodies relative to the bending tool with support and displacement forces. As a result, undesired sliding movements of the rolling bodies relative to the mold receptacles or relative to other retaining or guide rails can be avoided. In addition, a relatively low-noise displacement or replacement process of the bending tool can be achieved. This is the case in particular when the bending tool is moved at relatively high speeds of movement over transitions, transverse gaps or guide elements which are slightly offset from one another.

The invention may also be defined by the bending machine or the mould receiving part of the bending machine, which holds the bending mould described therein.

For a better understanding of the invention, it is described in detail with reference to the following figures.

In each case, the following are shown in a very simplified schematic representation:

fig. 1 shows an oblique overview of a crank-shaped bending tool in a tool holder;

fig. 2 shows a schematic cross-sectional view of a bending mould with differently arranged spacer elements (a-f) on or in the mould body;

fig. 3 shows a schematic view of an embodiment of a bending die with a spacer element comprising one rolling element (a) or two rolling elements (b) on or in the die shank;

FIG. 4 shows a schematic view of an embodiment of a bending mould with a spacer element housing;

FIG. 5 shows a schematic view of an embodiment of a bending die having a spacer element configured as a bending rod (a) or a beam-waist type bending rod and an adjusting device (b);

FIG. 6 shows a perspective view of a bent-out crank-like bending die having a plurality of spacer elements, which each comprise a spring-loaded bending rod;

fig. 7 shows a cross section of the bending die of fig. 6 in the region of the spacer element;

FIG. 8 shows a perspective view of a crank-shaped bending die with a plurality of spacer elements comprising spring-loaded rolling body receptacles;

fig. 9 shows a cross section of the bending die of fig. 8 in the region of the spacer element;

fig. 10 shows an alternative embodiment of the spacer element shown in fig. 9.

It should be noted that identical components in the different described embodiments are provided with the same reference numerals or the same component numbers, wherein the disclosure contained in all the descriptions can be advantageously transferred to components provided with the same reference numerals or the same component numbers. The positional references selected in the description, such as upper, lower, lateral, etc., also relate to the directly described and illustrated figures and can be advantageously transferred to new positions in the event of a change of position.

Fig. 1 shows a schematic view of a bending die 1 bent in a crank-like manner. The bending mould 1 comprises a mould body 3 having at least one mould stem 4 and a mould head 9. The mold stem portion 4 is for being accommodated in an accommodation well 15 of the mold accommodation portion 14. The die head 9 is formed in the bending direction directly on the die shank 4. As can be seen from fig. 1, the mold center of gravity 10 is located outside or laterally offset from the vertical plane of symmetry 17 of the receiving shaft 15. The tilting moment 13 is formed by the eccentric mold center of gravity 10. Fig. 1 schematically shows a situation in which the bending tool 1 is supported with its tool shank 4 in the recess 16 via the movement 8 in the tool receptacle 14. The tilting moment 13 is caused by the support on the movement 8, so that the mold body 3 touches the mold receptacle 14 in at least one contact position. In the case shown, such a contact point can occur between the die shank surface 7 and the inside of the receiving shaft 15 or also between the upper side 12 of the die shoulder and the lower side 19 of the die receiving part 14. The contact position is also configured between the mover 8 and the groove 16. Higher wear can occur at this contact location when the bending mould 1 is moved in the longitudinal direction 22.

Furthermore, it can be seen from fig. 1 that at least one clamping groove 6 is formed on the die shank 4 for tensioning the bending die 1 by means of a tensioning system or clamping system, not shown.

In fig. 2 to 5 different embodiments of a spacer element 2 are presented and schematically shown. The spacer element 2 shown here exerts a supporting force 23 on at least one surface of the mold receptacle 14, for example on the inner side 18 and/or the underside 19, thereby compensating for the tilting moment 13. According to the invention, at least one spacer element 2 comprises rolling elements 25, which are mounted with a preload 24 and are arranged on the mold body 3 or at least partially in the mold body. The spacer element 2 and/or the rolling elements 25 are mounted so as to be movable at least in the direction of the preload force 24. At least one rolling element 25 is arranged at least partially in a protruding manner with respect to a surface of the mold body 3 adjacent to the at least one rolling element, for example the mold shank surface 7 or the mold shoulder upper side 12.

In fig. 2, different arrangements and possible positioning of the spacer elements 2 on and/or within the mould body 3 are schematically shown.

Fig. 2a, 2b and 2f show that the spacer element 2 transmits the supporting force 23 in the transverse direction to the mold receptacle 14. The respective spacer element 2 is arranged here on or in the mold shank 4 of the mold body 3. In fig. 2a the spacer element 2 is arranged in the mold stem 4 such that it closes flush with the upper side 5 of the mold stem 4. In fig. 2b, the spacer element 2 is accommodated in the mold shank 4 such that the upper side 5 of the mold shank 4 can be substantially continuously formed in the longitudinal direction 22 and the transverse direction 21. These arrangements are advantageously transferred to a spacer element 2, schematically shown as a curved rod 31 in fig. 2 f.

Examples of the arrangement of the spacer elements 2 on or in the die head 9 or the die shoulder 11 are shown in fig. 2c, 2d and 2 e. The supporting force 23 is applied here essentially in the bending direction 20 or opposite thereto. In fig. 2c, the spacer element 2 is positioned in the die shoulder 11 such that at least one rolling element 25 can project at least partially above the upper side of the die shoulder. Similarly, fig. 2d schematically shows an arrangement of the spacer elements 2, wherein the spacer elements 2 are laterally fixed to the mold shoulder 11 in the transverse direction 21 by means of spacer element housings 30. Fig. 2e shows an embodiment in which the spacer element 2 comprises a bent rod 31 and is accommodated in the die head 9 such that the rolling bodies 25 can again project at least partially above the upper side 12 of the die shoulder.

The arrangements schematically shown in fig. 2a to 2f can be combined with one another or applied separately.

Fig. 3a and 3b and fig. 4 show an example of a spacer element 2, in which at least one rolling element 25 is arranged in a rolling element receptacle 27. The pretensioning force 24 can be applied directly between the mold body 3 and the rolling element receptacles 27 by means of, for example, one or more spring elements. The spring element is exemplarily shown as a helical spring, but a cup spring, a leaf spring, etc. may also be suitable for embodiments of the present invention. The rolling element receptacles 27 are not shown to be supported directly on the mold body 3, since the skilled person can easily imagine such an embodiment. The adjusting device 26 for setting the magnitude of the pretension 24 is described in detail below.

As can be seen in fig. 3a, the rolling elements 25 are rotatably arranged in the rolling element receptacles 27. The supporting force 23 is exerted by the transmission of the pretensioning force 24 to the rolling element receptacles 27. The rolling element receptacle 27 can have at least one stop element 28. A fixing member 29 in the form of a screw is connected to the mold body 3 or the mold shank 4. The limiting element 28 can have a recess or groove which allows the rolling element receptacle 27 or the spacer element 2 to be deflected in a limited manner in the direction of the preload force 24. The securing element 29 thus acts on the one hand as a stop in the transverse direction 21 and projects beyond at least part of the stop element 28 in the longitudinal and/or

transverse direction

22, 21, whereby an unintentional falling off of the spacer element 2 can be prevented. Fig. 3a also shows an adjusting device 26. The illustrated embodiment of the adjusting device 26 comprises at least one spring element for the applied pretensioning force 24, which is formed, for example, by two helical springs and a mating plate for supporting. Furthermore, the spring travel of the spring element can be set, for example, by means of an adjusting screw 47 or the like. Such an adjusting screw 47 is rotatably mounted in the mold body 3 or the mold shank 4 and serves for simple adjustment of the counter plate and thus of the spring path. Advantageously, the adjustment device 26 is arranged in the mould shank 4 such that no part projects above the mould shank surface 7.

With reference to the description of fig. 2 and 3a, fig. 3b schematically shows a further exemplary embodiment in which the spacer element 2 has two rolling bodies 25 arranged next to one another in the longitudinal direction 22. The mode of operation will not be repeated, see in particular the description of fig. 3 a.

Fig. 4 shows a further and possibly separate embodiment of the spacer element 2, in which the same reference numerals as in the preceding fig. 1 to 3 are used for the same components. The operation of applying the supporting force 23 by applying a predefinable prestress force 24 to the rolling elements 25 is analogous to that described in fig. 3a or 3 b. In fig. 4, a spacer element 2 arranged in a spacer element housing 30 is shown. The spacer element housing 30 serves for receiving the rolling element receptacles 27 of the at least one limiting element 28 and for supporting the adjusting device 26 relative to the rolling element receptacles 27. The rolling element receptacles 27 and the adjusting device 26 are thereby protected against contamination and/or mechanical influences from the outside. In the selected illustration, the two limiting elements 28 in the rolling element pockets 27 are partially formed as recesses. The spacer element housing 30 has a through-hole of complementary shape to it, which is not possible in cross-section, but which enables the fixing 29 to be mounted from the outside. The securing element 29 can in turn make the rolling element receptacle 27 deflect in a limited manner in the direction of the preload force 24. This arrangement is particularly space-saving. The adjusting device 26 or the adjusting screw 47 is also very simply accessible from the outside.

The embodiments of the spacer element 2 shown in fig. 3a, 3b and 4, viewed in conjunction with fig. 2, can also be arranged differently on or at least partially within the mould body 3. A detailed description of such alternative positioning and/or combination of spacer elements 2 will be clear to the skilled person and will therefore not be described in detail.

Fig. 5 schematically shows an exemplary embodiment in which the spacer element 2 is designed as a bent rod 31, so that the at least one rolling element 25 is arranged on the free end 32 and the fixed end 33 is fixed in the die head 9 perpendicularly and/or in the bending direction 20.

In fig. 5a, bending rod 31 is screwed into mold head 9 by means of a threaded section 34. It is also conceivable for the bending rod 31 to be fixed on its fixing end 33 outside the die head 9. As shown in fig. 5a, the bending rod 31 is deflected in the full direction 20 when the bending die 1 is accommodated in the die receptacle 14, as is schematically indicated by the movement arrow. The stiffness of flexure bar 31 may be set by the material of flexure bar 31 and the diameter and/or the bending length 36. The bending rod 31 bends when the rolling elements 25 come into contact with the underside 19 of the mold receptacle 14, as a result of which a preload 24 is applied to the rolling elements 25. In order to enable a limited deflection of the free end 32 of the bending rod 31, a receiving opening 46 is provided in the mold body 3. In this embodiment, the rolling elements 25 are therefore mounted so as to be movable at least in sections in the bending direction 20 and/or in the longitudinal direction 22.

Another possibility of implementing the spacer element 2 as a bent rod 31 is schematically shown in fig. 5 b. The adjusting device 26 can be seen in the illustrated drawing. The adjusting device 26 corresponding to the bending bar 31 can comprise an externally accessible adjusting screw 47 for setting the support distance 42 between the threaded section 34 and the support element 43 mounted movably transversely to the bending direction 20. In this way, the length of the bend 36 provided can be set by means of the adjusting device 26, and thus the pretension 24 or the support force 23 can be set. Furthermore, as can be seen from fig. 5b, the support element 43 supports the bending section 35 to form a two-point bearing. Preferably, the support element 43 is configured as a sleeve, which at least partially surrounds a portion of the bending section 35.

Furthermore, fig. 5b shows a further embodiment, in which the bending beam 31 is designed as a beam-waist bending beam 31. The bending section 35 is shown here as a first waist section 38 and the rolling element section 37 as a second waist section 39. At least one waist section diameter 40 of the first waist section 38 and/or the second waist section 39 is smaller than the threaded section diameter 41. Similar to the description of fig. 5a, the stiffness of the beam waist bending beam 31 can be set relatively simply by the local diameter and/or material etc. of the bending beam 31.

Fig. 1 to 5 also show the design of at least one moving element 8, which is formed on the mold rod 4 at least on one side in a protruding manner relative to the corresponding mold rod surface 7. Such a movement 8 is intended to be received in a recess 16 of the mould receiving part 14 and enables a movement of the bending mould 1 in the longitudinal direction 22. It has been found to be particularly advantageous if at least two moving parts 8 are configured side by side in the longitudinal direction 22 as sliding elements 44 or rolling elements 45. Such a sliding element 44 is preferably connected as a longitudinally extending sliding body to the mould shank 4 and is arranged at least on the side of the bending mould bearing the centre of gravity 10 of the mould. Similarly, the at least one movement 8 can be embodied as a rolling element 45. A schematic representation of this can be seen in fig. 1 to 5.

In a further embodiment, at least two kinematics 8 are configured on opposite sides of the mold stem 4 in the transverse direction 21, as can be easily deduced from the overview and disclosure of fig. 1 to 5.

In a special embodiment, the movement element 8 or the sliding element 44 can also be designed as an integral extension of the mold shank 4 and can therefore be produced in one piece with the mold shank 4. Such a movement element can preferably have a greater extension in the longitudinal direction 22 than in the bending direction 20, as a result of which good unloading can be achieved. The moving element 8 configured as a forward extension of the mold shank 4 is preferably provided with a surface layer, not shown, having a low coefficient of friction.

Fig. 6 and 7 show a further and possibly separate embodiment of the crank-like bending tool 1, in which the same reference numerals as in the previous fig. 1 to 5 are again used for the same components. The foregoing description may also be applicable to the same parts having the same reference numerals. The bending die 1 comprises, owing to its relatively large longitudinal extension, a total of three moving parts 8 spaced apart from one another, which are held on or in the die shank 4. Each moving part 8 has a respective rolling pin 48, which is preferably formed on one side and extends through the die shank 4 in the transverse direction 21 via a receiving bore 50. The bore 50 is embodied continuously in a cylindrical manner and can therefore be produced in a simple manner. The roll pin 48 is mounted so as to be freely rotatable relative to the tool shank 4 via at least one rotary bearing element 49, preferably via two rotary bearing elements 49 which are spaced apart axially from one another. The at least one rotary bearing element 49 is preferably formed by a plain bearing element 51, but may alternatively be formed by a rolling bearing element, in particular by a cylindrical roller bearing or a needle bearing. The rotary bearing elements 49, which are preferably embodied in pairs, can be pressed into and/or glued into the receiving bore 50. The retaining flange 48' of the roll pin 48, which is arranged between the pair of rotary bearing elements 49, can advantageously serve as an axial anti-displacement means for the rotatably mounted roll pin 48.

The

end portions

52, 53 of the rolling pin 48 which lie opposite one another project in each case relative to the tool shank surface 7 and, when the bending tool 1 is accommodated unloaded in the tool holder 14, but is not clamped therein, but rather is mounted so as to be movable in the longitudinal direction 22, can thereby roll into the recess 16 (fig. 1) of the tool holder 14 which accommodates the shaft 15. Only by activating, if necessary, known clamping devices (fig. 1) on or in the tool holder 14 is the at least one bending tool 1 held or clamped in a stationary manner and is usually pressed by its at least one tool shoulder upper side 12 against the lower side 19 of the tool holder 14, which is formed on at least one side. Such a clamping device can, as is known, comprise a plurality of wedge-shaped extending clamping pistons arranged in pairs or opposite each other, which can interact with a clamping groove 6 of wedge-shaped or trapezoidal cross-section of the die shank 4.

Preferably, the spacer elements 2 are formed in the region of the longitudinal ends of the bending mould 1, respectively, with reference to the longitudinal direction 22. The spacer element 2 is constructed according to the embodiment of fig. 5a or 5 b. To avoid repetition, reference is made to the corresponding reference numerals and previous description.

Fig. 8 and 9 show a further and possibly separate embodiment of the crank-like bending tool 1, in which the same reference numerals as in the previous fig. 1 to 7 are again used for the same components. Parts of the preceding description may also be transferred to the same parts having the same reference numerals. Two spacer elements 2 are provided, spaced apart from one another in the longitudinal direction 22, which are formed on one of the two mold shoulders 11 or in one of the two mold shoulder upper sides 12. Each spacer element 2 has a block-shaped or strip-shaped rolling element receptacle 27 for holding a rolling element 25 thereon. The rolling elements 25 are in this case embodied in the form of cylinders or rollers and are directly mounted rotatably in the rolling element receptacles 27. The rolling elements 25 can therefore also be referred to as roller bodies 54.

The roller body 54, which is preferably made of metal, in particular steel, is mounted so as to be rotatable in a receiving bore 55, which is formed in the rolling element receiving part 27. The axis of rotation or longitudinal axis of the roller body 54 extends in the transverse direction 21 relative to the bending tool 1. In this case, a partial section of the outer surface of the cylindrical roller body 54 projects relative to the outer surface 57 of the rolling element receptacle 27. This is achieved by a suitable positioning of the longitudinal axis 56 of the bore 55 relative to the rolling element receptacles 27. The axial length of the roller body 54 is preferably a multiple of its diameter.

The roller body receptacle 27 is arranged partially or partially in a recess 58, the recess 58 being formed in at least one die shoulder 11 or in at least one die shank surface 7. The rolling element receptacles 27 are held in a relatively movable manner by the wall surfaces of the recesses 58 and are mounted in a spring-elastic manner, in particular under the action of a biasing force. Preferably, a spring-loaded sliding mobility is present upstream of the rolling element receptacles 27 and the recesses 58. The respective spacer element 2 is therefore integrated at least partially, in particular largely, in the mold shoulder 11, as a result of which a robust and at the same time cost-effective embodiment is achieved.

The cylindrical roller body 54 is preferably made of metal, while the rolling element receptacle 27 can be made of a different material, in particular plastic. The block-shaped or strip-shaped rolling element receptacles 27 can also be formed from a metallic plain bearing material, in particular with a brass component.

In order to prevent the spacer element 2 and the bending tool 1 from becoming undesirably jammed or jammed when the bending tool 1 is moved manually and/or automatically, the rolling element receptacles 27 may also have thrust ramps 59 in at least one distal end section thereof or a crowned surface 57 at least in a middle section thereof. The end section of the rolling element receptacle 27 relates here to the longitudinal direction 22 of the bending tool 1 or of a bending machine equipped with a bending tool.

The supporting force 23 of the bending tool 1, which supporting force can be applied by the spacer element 2 and is elastically bent, is provided by a prestressing force 24 acting on the rolling element receptacles 27. In the embodiment of fig. 9, the pretensioning force 24 acting on the rolling element receptacles 27 and the at least one rolling element 25 is provided by exactly two or by at least two

spring elements

60, 61 which are spaced apart from one another in the longitudinal direction 22 and which are supported on the rolling element receptacles 27. Preferably,

spring elements

60, 61, which can be embodied as helical springs, act on the end sections of the rolling element receptacles 27. The roller body 54 is arranged in the region of the rolling element receptacle 27 in the longitudinal middle, i.e. in the section located between the two

spring elements

60, 61. This makes it possible to achieve a mechanically stable state of the spacer element 2, in particular of the spring-elastically flexible rolling element receptacles 27 of block-shaped or strip-shaped design.

As an alternative to the embodiment of fig. 9, two rotatably mounted roller bodies 54 can also be provided on the rolling element receptacles 27, as is shown by way of example in fig. 10. In this case, two cylindrical roller bodies 54 are arranged in the region of the longitudinal ends of the rolling element receptacles 27, while in the middle section thereof the limiting element 28 is positioned. In particular, only a single fastening element 29 is provided here, to which the spacer element 2 or its rolling element receptacles 27 are fastened or fastenable in a loss-proof manner on the bending tool 1. The fastening elements 29, in particular individual screws, can be inserted into the central bores in the rolling element receptacles 27 from the upper side 12 of the mold shoulder, as a result of which a quick and simple installation or maintenance of the spacer element 2 is possible.

As is apparent from fig. 7, at least one of the rolling bodies 25 can have a rolling outer surface 62 which increases friction with respect to a metal surface, in particular made of plastic, preferably elastomeric plastic. The rolling bodies 25 can be coated accordingly on their rolling surfaces or can be made of a corresponding plastic for the most part. This can be expedient in particular in embodiments in which the spacer element 2 is combined with freely protrudingly supported bending rods 31.

These embodiments are possible variants, wherein it is to be noted here that the invention is not limited to the specifically illustrated variants, but various combinations of the individual variants with one another are also possible and are within the ability of the person skilled in the art on the basis of the technical teaching of the invention.

The scope of protection is determined by the claims. The specification and drawings are used to interpret the claims. Individual features or combinations of features of different embodiments shown and described may independently represent independent inventive aspects. The object of the independent invention can be derived from the description.

All statements of value ranges in the specification are to be understood as including any and all subranges therein, e.g. statements 1 to 10 are to be understood as including all subranges from a lower limit of 1 and an upper limit of 10, i.e. all subranges beginning with a lower limit of 1 or more and ending with an upper limit of 10 or less, e.g. 1 to 1.7, or 3.2 to 8.1, or 5.5 to 10.

Finally, it should be pointed out that the elements are partially not shown to scale and/or enlarged and/or reduced in order to better understand the construction.

List of reference numerals

1 bending die

2 spacer element

3 main body of mould

4 mould rod part

5 Upper side of the mold Stem portion

6 clamping groove

7 mold shank surface

8 moving part

9 die head

10 center of gravity of die

11 mould shoulder

12 upper side of the shoulder of the die

13 moment of tilt

14 mold receiving part

15 accommodation shaft

16 grooves

17 plane of symmetry

18 inside of the accommodation shaft

19 underside of the mold receiving part

20 direction of bending

21 transverse direction

22 longitudinal direction

23 holding power

24 pretension force

25 rolling element

26 adjusting device

27 rolling element housing part

28 position limiting element

29 fixing piece

30 spacer element housing

31 bending rod

32 free end portion

33 fixed end part

34 thread section

35 curved section

36 bending length

37 rolling element segment

38 first beam waist section

39 second corset section

Diameter of waist area of 40

41 thread section diameter

42 support spacing

43 support element

44 sliding element

45 rolling element

46 receiving port

47 adjusting screw

48 roll pin

48' holding flange

49 rotating support element

50 receiving hole

51 plain bearing element

52 end section

53 end section

54 cylindrical roller body

55 holes

56 longitudinal axis

57 upper side

58 recess

59 thrust ramp

60 spring element

61 spring element

62 rolling outer surface

Claims

1. Bending die (1) for bending machines bent like a crank, said bending die (1) comprising:

-a die body (3) having at least one die shank (4) for accommodating the bending die (1) at least partially in a bending direction (20) in an accommodation well (15) of a die accommodation (14) of a bending machine provided for this purpose and a die head (9) which is connected to the die shank (4) in the bending direction (20), the die head (9) having a die center of gravity (10) which lies outside a vertical plane of symmetry of the accommodation well (15) and having a die shoulder (11) at least on one side in a transverse direction (21),

-at least one moving part (8) arranged on the die stem (4) for moving the bending die (1) in the longitudinal direction (22) of the bending machine and accommodated in a recess (16) of a die receptacle (14) of the bending machine, the moving part (8) being configured on the die stem (4) at least on one side in a protruding manner with respect to a respective die stem surface (7), and

-at least one spacer element (2) for applying a supporting force (23) to at least one surface (18, 19) of the mould receptacle (14) opposite to a tilting moment (13) caused by a deviation of the mould centre of gravity (10) from a plane of symmetry (17) in a lateral direction (21),

it is characterized in that the preparation method is characterized in that,

the at least one spacer element (2) comprises at least one rolling element (25) supported with a preload force (24), wherein the rolling element (25) is supported on the mold body (3) at least in the direction of the preload force (24) in a movable manner or at least partially within the mold body (3) and is arranged at least partially in a protruding manner relative to a surface of the mold body (3) adjacent to the at least one rolling element (25).

2. Bending die (1) bent into crank shape according to claim 1, wherein the at least one rolling body (25) is arranged on the die body (3) and/or at least partially in the die body (3) to apply the supporting force (23) perpendicular to a bending direction (20) or a transverse direction (21) onto an inner side (18) of the receiving well (15) and/or along a bending direction (20) to an underside (19) of the die receiving portion (14).

3. Bending die (1) according to claim 1 or 2, wherein the at least one spacer element (2) has an adjusting device (26) for setting the magnitude of the pretension force (24).

4. Bending mould (1) according to claim 1 or 2, wherein the spacer element (2) comprises at least two rolling bodies (25).

5. Bending die (1) bent into crank shape according to claim 1 or 2, wherein the at least one spacer element (2) comprises a rolling element receptacle (27) and the at least one limiting element (28), the limiting element (28) being configured to be movably connected with the die body (3) by means of at least one fixing element (29) in the direction of the pretension force (24) for limiting a deflection of the rolling element receptacle (27) or of the rolling elements (25).

6. Bending mould (1) according to claim 5, wherein said at least one spacer element (2) is arranged in a spacer element housing (30), said spacer element housing (30) at least for accommodating said rolling element pockets (27) and at least one limiting element (28) and for supporting an adjusting device (26) relative to said rolling element pockets (27).

7. Bending mould (1) according to claim 6, wherein said at least one spacer element (2) is arranged outside the mould head (9) for supporting the bending mould (1) on the underside (19) of the mould receptacle (14).

8. Bending mould (1) according to claim 1 or 2, wherein the spacer element (2) is configured as a bending rod (31) such that the at least one rolling body (25) is arranged on a free end (32) of the bending rod (31) and a fixed end (33) of the bending rod (31) is fixed in the mould body (3) perpendicular to the bending direction (20) and/or along the bending direction (20).

9. Bending die (1) bent into crank shape according to claim 8, characterized in that the at least one rolling element (25) is arranged at least partially protruding with respect to the upper side (12) of the die shoulder (11) and the rolling element (25) is fixed on the die head (9) perpendicularly to the bending direction (20) by means of a fixing end (33) of the bending rod (31) for exerting a supporting force (23) in the bending direction (20) with respect to the die receptacle (14).

10. Crank-like bending die (1) according to claim 8, wherein the bending rod (31) comprises at least one thread section (34) for accommodating the bending rod (31) in the die head (9) and/or the die shank (4), a bending section (35) with a predeterminable bending length (36) and a rolling body section (37), and an adjusting device (26) for setting the pretension (24) by adjusting a predeterminable support spacing (42) between the thread section (34) and the rolling body section (37) is arranged to at least partially support the bending section (35).

11. Crank-bent bending die (1) according to claim 10, wherein the bending rod (31) is configured as a beam waist type bending rod (31), wherein the bending section (35) is configured as a first beam waist section (38) and the rolling body section (37) is configured as a second beam waist section (39) and at least one beam waist section diameter (40) of the first beam waist section (38) and/or the second beam waist section (39) is smaller than a thread section diameter (41).

12. Bending mould (1) according to claim 10, wherein the adjusting means (26) for adjusting the preset support pitch (42) comprises a support element (43) at least partially surrounding the bending section (35).

13. Bending mould (1) according to claim 1 or 2, wherein at least two moving parts (8) are configured side by side in the longitudinal direction (22) as sliding elements (44) or as rolling elements (45).

14. Bending die (1) according to claim 1 or 2, wherein at least two moving parts (8) are configured on opposite sides of the die shank (4) in the transverse direction (21).

15. Bending die (1) according to claim 1 or 2, wherein the at least one moving element (8) is configured integrally with the die shank (4) as a forward extension.

16. Bending die (1) bent into crank shape according to claim 1 or 2, wherein said at least one moving part (8) comprises a rolling pin (48), said rolling pin (48) being rotatably supported in said die stem (4) with respect to said die body (3) by means of at least one rotating support element (49).

17. Crank-bending mould (1) according to claim 16, characterised in that the at least one rotary bearing element (49) is formed by at least one plain bearing element (51) or rolling bearing element held in a receiving bore (50) of the mould shank (4).

18. Bending die (1) bent into crank shape according to claim 16, wherein the at least one rolling pin (48) is configured in one piece and simultaneously penetrates the die shank (4) with at least one rotary bearing element (49) connected in between, such that its mutually opposite end sections (52, 53) project respectively relative to the mutually opposite die shank surfaces (7).

19. Bending die (1) bent into a crank shape according to claim 1 or 2, wherein the at least one spacer element (2) comprises a rolling body receptacle (27), in which rolling body receptacle (27) at least one rolling body (25) configured as a cylindrical roller body (54) is rotatably supported.

20. Bending die (1) according to claim 19, wherein the at least one cylindrical roller body (54) is held in at least one bore (55) formed in the rolling element receptacle (27), wherein a longitudinal axis (56) of the at least one bore (55) is positioned such that a portion of an outer surface of the cylindrical roller body (54) protrudes relative to the outer surface of the rolling element receptacle (27).

21. Bending die (1) bent into crank form according to claim 19, characterized in that the rolling element receptacle (27) is partially received in a recess (58) in the at least one die shoulder (11) or in the at least one die shank surface (7) and is spring-elastically bendable supported relative to the recess (58) by applying a pretensioning force (24).

22. Bending die (1) bent into crank shape according to claim 19, wherein the rolling element receptacle (27) has a thrust ramp (59) in its end section in at least one longitudinal direction (22) or a crowned surface at least in its middle section.

23. Bending die (1) bent into crank shape according to claim 19, wherein the at least one cylindrical roller body (54) consists of metal and the rolling element receptacles (27) consist of a different material than it.

24. Bending die (1) according to claim 19, wherein the pretensioning force (24) acting on the rolling element receptacle (27) and the at least one rolling element (25) is provided by at least two spring elements (60, 61) spaced apart from each other in the longitudinal direction (22).

25. Bending mould (1) according to claim 19, wherein said at least one rolling body (25) has a rolling outer surface (62) increasing friction with respect to a metal surface.

26. Bending die (1) bent into crank shape according to claim 4, wherein the rolling bodies are arranged side by side in rolling body pockets (27).

27. Bending die (1) bent into crank shape according to claim 8, wherein the fixed end (33) of the bending rod (31) is fixed in the die head (9) in the bending direction (20).

28. Bending mould (1) according to claim 12, wherein said supporting element (43) is sleeve-shaped.

29. Bending die (1) according to claim 14, wherein at least two moving parts (8) are symmetrically oppositely configured in the transverse direction (21).

30. Bending mould (1) according to claim 23, wherein the rolling element pockets (27) are made of plastic.

31. Bending die (1) according to claim 24, wherein a spring element (60, 61) acts on the rolling element pockets (27).

32. Bending mould (1) according to claim 25, wherein said at least one rolling body (25) is made of plastic.

33. Bending mould (1) according to claim 25, wherein said at least one rolling element (25) is made of an elastomeric plastic.