Roll forming device for the production of a partially hardened profile part

Abstract

Roll forming device (100) for producing a partially hardened profile part (12) formed from sheet metal material (11), comprising several sets of rollers (30, 40, 50, 60) which serve to produce an axially extending profile part (12) by forming the sheet metal material (11), characterized in that, for bringing about the partial hardening of the sheet metal material (11), at least one set of rollers (50) is designed with at least one integrated heating device (55, 56) for the partial heating of the sheet metal material (11), wherein the integrated heating device (55, 56) is an inductive heating device, and that at least one set of rollers (60) is provided following the set of rollers (50) with the integrated heating device (55, 56), which has at least one integrated cooling device (65) for the targeted cooling of the previously partially heated sheet metal material (11). exhibits.

Description

The invention relates to a roll forming device for producing a partially or area-hardened (metallic) profiled part according to the type specified in more detail in the preamble of claim 1. Roll forming is generally understood as the successive forming of a flat or pre-formed sheet metal material into an axially extending profiled part with a desired final cross-section. For this purpose, a roll forming machine comprises several appropriately designed and arranged sets of rollers (or roller sets) between which the sheet metal material is continuously passed and successively formed or calibrated. A roller set comprises at least two roller bodies (or roller bodies) between which the sheet metal material passes. German patent DE 101 20 063 A1 describes a roll forming device that enables the production of partially hardened or partially tempered profiled parts. In this process, the sheet metal is inductively heated to the temperature required for hardening before or after passing through the forming roller sets and is then quenched and hardened by a cooling unit. Roll forming in combination with partial hardening of the sheet metal allows for the highly efficient and economical production of stress-optimized profiled parts. Regarding the prior art, reference is also made to DE 10 2009 051 822 B3, which describes, among other things, a device for manufacturing sheet metal parts, comprising a continuous furnace for heating blanks, a conveyor system for transporting the heated blanks, and a deep-drawing press for forming and cooling the blanks. The conveyor system has upper and lower conveyor rollers forming a single unit. The cooled and / or, for example, inductively heated upper and lower conveyor rollers of the conveyor system can be equipped with a contact force control device on their drive shafts to additionally produce different sheet thicknesses by rolling partial areas. However, roll forming is not mentioned. EP 1 001 658 A1 relates to an induction heating system for a thermal roller with a roller shell made of a ferromagnetic material and an inductor coil inside the roller shell for low-loss transmission and process-compliant adjustment of the heating power by generating eddy currents of uniform density in the entirety or in selectively selectable zones of the outer surface of the roller shell. From EP 2 305 392 A1 a method for rolling rolled material, in particular heavy plate, is known in which a cooling phase is carried out between two hot rolling operations, during which excessive cooling of the edge area is counteracted; furthermore, a rolling mill with corresponding facilities for thermomechanical rolling and cooling of the rolled material is described. However, the roll forming device known from DE 101 20 063 A1 for the production of a partially hardened profile part has several disadvantages, such as a large overall length. It is therefore an object of the present invention to optimize the roll forming device known from DE 101 20 063 A1. This problem is solved by a roll forming device according to the invention with the features of claim 1. Advantageous and preferred embodiments are specified in the dependent claims. The roll forming device according to the invention for producing a partially hardened profiled part formed from sheet metal comprises several sets of rollers that serve to produce an axially extending profiled part by forming the sheet metal, for which purpose the sheet metal is continuously passed between the sets of rollers and thereby formed or calibrated. It is provided that, to effect partial hardening or tempering in the sheet metal, at least one set of rollers is designed with at least one integrated heating device for partially heating the (passed through) sheet metal, and that this roll forming device further comprises at least one cooling device downstream of this set of rollers (in the direction of travel of the sheet metal) for the targeted cooling of the previously partially heated sheet metal, wherein the partial hardening or tempering is effected by the targeted cooling. Targeted cooling refers to the active, rather than random or uncontrolled, cooling of previously partially heated sheet metal material, with the aim of achieving a cooling rate sufficient for hardening or the desired increase in strength (e.g., more than 30 K / s or more than 50 K / s). In particular, it is provided that at least one roller set following the roller set with the integrated heating device (considered in the direction of flow of the sheet material) has at least one integrated cooling device for the targeted cooling of the previously partially heated sheet material, whereby the partial hardening of the sheet material takes place. Furthermore, integrated and non-integrated cooling devices can be combined. The profiled part produced with the roll forming device according to the invention can have an open or a closed end cross-section. It is preferred that the end cross-section has a complex geometry, which means that the end cross-section deviates from a simple geometric shape (for example, a triangle, rectangle, and the like). Due to partial hardening, the profiled part produced with the roll forming device according to the invention exhibits stress-adapted, graduated strength properties. The roll forming device according to the invention is particularly suitable for the production of body components for passenger car bodies. The roll forming device according to the invention can include a cutting device for separating individual components from the continuously produced profiled part. The heating unit integrated into a roller set is designed to partially or selectively heat the sheet metal to the temperature required for hardening as it passes through the roller set. Specifically, this is a temperature above the austenitizing temperature of the sheet metal (for example, above 900°C). The sheet metal is typically a hardenable steel, such as a 16MnB5 or 22MnB5 alloy. The sheet metal may optionally have a corrosion protection coating. The heating device integrated into a roll set can be arranged in one or more roll bodies within that roll set. The same applies to the cooling device integrated in a subsequent roll set. An integrated heating or cooling device can extend (in the axial direction of the roll body and thus transversely to the axial extent of the profile part to be produced) over a width section of the roll body in order to achieve local heating or cooling of the sheet metal material being processed in that section or area. A roll body can have several heating or cooling devices, which in particular extend over different width sections. An integrated cooling device within a roller set enables active cooling of previously heated sheet metal areas, achieving a cooling rate that leads to hardening or increased strength in these areas. Depending on the design, the cooling device can cool only part of the surface (active area) of the roller body that comes into contact with the sheet metal, or the entire surface, to achieve active cooling of the sheet metal. Preferably, the cooling device is operated with a cooling liquid, although the use of a cooling gas is also conceivable. The roll forming device according to the invention can have several sets of rolls with integrated heating devices and / or several sets of rolls with integrated cooling devices. It is preferred that a set of rolls with at least one integrated cooling device immediately follows a set of rolls with at least one integrated heating device with respect to the direction of flow of the sheet material. The roll forming device according to the invention has many advantages. One advantage, for example, is that the integration of the heating and cooling units into the roll sets results in a significantly shorter overall length compared to previously known roll forming devices. A further advantage is that the direct contact between the roll bodies and the sheet metal allows for more targeted and energy-efficient heating and cooling of the sheet metal compared to previously known roll forming devices. According to the invention, it is also provided that the integrated heating device is an inductive heating device and that the electrical contacting of the inductive heating device integrated in a rotating roller body is carried out by at least one sliding contact device, similar to the rotor of an electric motor. Between the roller set with the integrated heating device and the roller set with the integrated cooling device, at least one shielding device, for example in the form of a shielding plate, can be arranged in order to at least reduce or prevent the cooling (in particular by heat radiation and / or convection) of the partially heated sheet material moving in the through-direction. A roller set with at least one integrated heating device can be a forming roller set. In such a roller set, the sheet metal material is formed and simultaneously partially heated. However, a roller set with at least one integrated heating device can also be a non-forming roller set. A non-forming roller set can, for example, be a form-calibrating roller set, which is connected downstream of a forming roller set or several forming roller sets with respect to the flow direction of the sheet metal material. A non-forming roller set with at least one integrated heating device can also serve solely the purpose of partially heating the sheet metal material, whereby the roller bodies can, however, have a shape-maintaining function. Analogous to the preceding explanations, a roller set with at least one integrated cooling device can be a forming roller set. In such a roller set, the sheet metal material is formed and simultaneously cooled. However, a roller set with at least one integrated cooling device can also be a non-forming roller set. A non-forming roller set with at least one integrated cooling device can, for example, be a form-calibrating roller set downstream of a heating roller set. A non-forming roller set with at least one integrated cooling device can also serve solely the purpose of cooling the partially heated sheet metal material, although the roller bodies can still have a shape-maintaining function. The roll forming device according to the invention can include a control unit for controlling or regulating the integrated heating unit and / or the integrated cooling unit. The control unit enables, in particular, the switching on and off of the integrated heating unit and / or the integrated cooling unit, as well as the adjustment of the heating or cooling capacity. Furthermore, sensors can be provided to detect current operating parameters, such as the temperature of the roll bodies (or their surfaces), the temperature of the sheet material, or the throughput speed of the sheet material, and transmit this information to the control unit. The control device can be configured to activate at least one integrated heating device for a specific period of time and / or over a defined rotation angle of the roller body in question. This allows the sheet metal material being processed to be heated in a defined length section (i.e., in a section or...). Heat the area along the axial extent of the profile part to be manufactured. The relevant rotation angle can be less than or greater than 360°. The invention is explained in more detail below by way of example and without limitation with reference to the schematic figures. Fig. 1 shows a side view of a roll forming device according to the invention. Fig. 2 shows a front view of a roll set of the roll forming device from Fig. 1 with two integrated inductive heating devices. Fig. 3 shows a front view of an alternative embodiment of the roll set from Fig. 2. Fig. 4 shows a front view of a roll set of the roll forming device from Fig. 1 with an integrated cooling device. Fig. 1 shows a roll forming device according to the invention, designated 100 in general. The roll forming device 100 comprises several sets or pairs of rollers 30, 40, and 50, each consisting of an upper roller body and a lower roller body, forming a roll forming unit 20. A flat sheet material 11 (starting sheet material) unwound from a coil 10 is continuously fed through the roll forming unit 20 and successively formed by the forming roller sets 30, 40, and 50 into an axially extending profiled part 12 with a complex final cross-section (see Fig. 2). The direction of travel of the sheet material 11 is indicated by the arrow D. The roll forming device 100 further comprises a calibration roller set 60 following the output roller set 50 of the roll forming unit 20. In the direction of travel D, a cutting device 90 follows the calibration roller set 60 in order to separate individual components 13 from the continuously produced profile part 12. According to the invention, the initial roller set 50 has two integrated or structurally incorporated inductive heating devices 55 and 56, which serve to partially heat the sheet metal material 11 that has already been formed into a profile part 12. Furthermore, the calibration roller set 60, which follows the initial roller set 50 in the direction of travel D, has an integrated or structurally incorporated cooling device 65, with which the previously partially heated sheet metal material 11 can be selectively cooled in order to achieve partial hardening of the sheet metal material 11 according to known metallurgical mechanisms. The heating devices 55 and 56 and the cooling device 65 are arranged in the upper roller bodies by way of example. Alternatively or additionally, they can also be arranged in the lower roller bodies. Moreover, the number of roller sets shown is also only exemplary. The reference 70 designates shielding devices to reduce the cooling of the sheet metal material 11 or the profiled part 12 moving in the through-direction D between the roller set 50 and the roller set 60. The shielding devices 70 can optionally also be equipped with heating devices. The reference 80 designates a control unit for controlling and / or regulating the heating devices 55 and 56 and / or the cooling device 65. Fig. 2 shows the output roller set 50. This comprises an upper roller body 51 and a lower roller body 52, between which the sheet metal material 11 is formed. The axes of rotation, which correspond to the longitudinal axes, are labeled A1 and A2. Two inductive heating devices 55 and 56 are arranged in the upper roller body 51. The number of two inductive heating devices is merely an example. The heating devices 55 and 56 are designed as induction loops in the form of circumferential rings, with these circumferential rings being seated in corresponding groove-like recesses in the surface or effective area of ​​the upper roller body 51 (see the illustrated cutout) and thus structurally integrated into the upper roller body 51. The groove-like recesses can, for example, be milled grooves.The fastening and electrical insulation of the inductive heating devices 55 and 56 are not shown in detail. The inductive heating devices 55 and 56 are electrically contacted by means of sliding contact devices. The sliding contact devices comprise ring contact elements 58, which are arranged on the upper roller body 51, and contact brushes 59 that press against these ring contact elements 58. The electrical contacting of the inductive heating devices 55 and 56 can also be effected in another way. The inductive heating devices 55 and 56 are arranged in the upper roller body 51 such that the sheet metal material 11 passing between the upper roller body 51 and the lower roller body 52 can be heated selectively in the region of the inclined flanks with respect to the cross-sectional geometry shown. By a different arrangement of the inductive heating devices 55 and 56, other areas of the sheet metal material 11 can also be heated (with respect to the cross-sectional geometry shown). The sheet metal material 11 is heated in a known manner by the local induction of eddy currents in the sheet metal material 11, whereby heat is generated directly in the sheet metal material 11. The upper roller body 51 remains essentially unheated. By selectively switching the inductive heating devices 55 and 56 on and off, the sheet metal material 11 can be heated selectively in a defined length section (i.e., perpendicular to the plane of representation in Fig. 2). The switching on and off of the inductive heating devices 55 and 56 can, for example, be dependent on a rotation angle of the upper roller body 51. The two inductive heating devices 55 and 56 can be switched on and off independently of each other, and their heating power can be varied. The switching on and off, as well as the variation of the heating power, is carried out by the control unit 80. Fig. 3 shows an alternative embodiment of the output roller assembly 50. Functionally identical components are designated with the same reference numerals as in Fig. 2, with the letter 'a' appended for differentiation. In contrast to the embodiment shown in Fig. 2, the inductive heating elements 55a and 56a are embedded near the surface in the base material of the upper roller body 51a. The inductive heating elements 55a and 56a are also designed as circumferential rings. The electrical connection of the inductive heating elements 55a and 56a to the ring contact elements 58a is shown with dotted lines. Otherwise, the explanations above regarding the embodiment shown in Fig. 2 apply. The sheet metal material 11, which is partially heated by the initial roller set 50 or 50a, is subsequently cooled in a targeted manner in the calibration roller set 60 and simultaneously calibrated in shape, resulting in a partial hardening of the profile part 12, such that it has an increased hardness or strength in the area of ​​the inclined flanks compared to the other areas. Fig. 4 shows the calibration roller set 60. This comprises an upper roller body 61 and a lower roller body 62, which are essentially identical in their external dimensions to the roller bodies 51 and 52 of the initial roller set 50 and 50a, respectively. The longitudinal axes corresponding to the axes of rotation are labelled A3 and A4. The upper roller body 61 has a cooling device in the form of several axially extending cooling channels 65, through which a cooling medium, such as a cooling liquid, can flow, thereby enabling active cooling of the surface or the effective area of ​​the upper roller body 61, which is necessary for the targeted cooling of the heated sheet metal areas. The connection of the cooling channels 65 to a cooling circuit is not shown in detail. In the roll forming device 100 shown in Fig. 1 and described above, the inductive heating devices are integrated into a forming roller set (roll set 50). The cooling device is integrated into a form-calibrating roller set (roll set 60). However, the heating and / or cooling devices can also be arranged in other roller sets. For example, the inlet roller set 30 of the roll forming unit 20 or a roller set upstream of the roll forming unit 20 can also be designed with an integrated heating device for the partial heating of the sheet material 11. For further details, please refer to the explanations above. In contrast to the embodiment of a roll forming device 100 shown in Fig. 1, at least one cooling device, and in particular a non-contact cooling device instead of the shielding devices 70 shown, can be provided between the output roll set 50 and the subsequent calibration roll set 60. Such a cooling device enables the sheet material 11, which is partially heated in the output roll set 50, to be cooled upstream before it reaches the cooling calibration roll set 60. This allows the overall achievable cooling capacity to be increased and / or the cooling device integrated in the calibration roll set 60 to be designed for a low cooling capacity. In such a cooling device, which is not integrated into a roll set, the partially heated sheet material 11 can be cooled, for example, by means of oil, an oil-water emulsion, gas, or air. With appropriate dimensioning of such a non-integrated cooling device, the cooling device integrated in the calibration roller set 60 can potentially be omitted. The sheet metal material 11, partially heated in the output roller set 50 by means of the inductive heating devices 55 and 56, is then cooled only by such a non-integrated cooling device, whereby the partial hardening of the sheet metal material 11 takes place. The calibration roller set 60 serves here only for the shape calibration of the already partially hardened sheet metal material 11. Reference symbol list 10 Coil 11 Sheet metal strip 12 Profile part 13 Component 20 Roll forming unit 30 Infeed roller set 40 Middle roller set 50 Outfeed roller set 51 Upper roller body 52 Lower roller body 55 Inductive heating device 56 Inductive heating device 58 Ring contact element 59 Contact brush 60 Calibration roller set 61 Upper roller body 62 Lower roller body 70 Shielding device 80 Control device 90 Cutting / separating device 100 Roll forming device A Longitudinal axis, axis of rotation D Flow direction Sheet material

Claims

Roll forming device (100) for producing a partially hardened profile part (12) formed from sheet metal material (11), comprising several sets of rollers (30, 40, 50, 60) which serve to produce an axially extending profile part (12) by forming the sheet metal material (11), characterized in that, for bringing about the partial hardening of the sheet metal material (11), at least one set of rollers (50) is designed with at least one integrated heating device (55, 56) for the partial heating of the sheet metal material (11), wherein the integrated heating device (55, 56) is an inductive heating device, and that at least one set of rollers (60) is provided following the set of rollers (50) with the integrated heating device (55, 56), which has at least one integrated cooling device (65) for the targeted cooling of the previously partially heated sheet metal material (11). exhibits. Roll forming device (100) according to claim 1, characterized in that the electrical contacting of the integrated inductive heating device is carried out by at least one sliding contact device (58, 59). Roll forming device (100) according to claim 1 or 2, characterized in that at least one shielding device (70) is arranged between the roller set (50) with the integrated heating device (55, 56) and the roller set (60) with the integrated cooling device (65) in order to at least reduce the cooling of the partially heated sheet material (11). Roll forming device (100) according to one of the preceding claims 1 to 3, characterized in that the roller set with the integrated heating device (55, 56) is a forming roller set (50). Roll forming device (100) according to one of the preceding claims 1 to 3, characterized in that the roller set with the integrated heating device (55, 56) is not a forming roller set. Roll forming device (100) according to one of the preceding claims 1 to 5, characterized in that the roller set with the integrated cooling device (65) is a forming roller set. Roll forming device (100) according to one of the preceding claims 1 to 5, characterized in that the roller set with the integrated cooling device (65) is not a forming roller set (60). Roll forming device (100) according to one of the preceding claims, characterized in that it has a control device (80) for controlling or regulating the integrated heating device (55, 56) and / or the integrated cooling device (65).

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