ES2467146T3 - Bending procedure and bending device - Google Patents

Abstract

Bending procedure, in which when approaching a matrix (2, 2 ') that has a bending edge (1, 1') and a bending punch (4, 4 ') that has a pivoting element (3, 3' ), the pivoting element (3, 3 ') is brought into contact with a clamping section (5, 5', 5 ") of a sheet (6, 6 ', 6", 6 "') arranged between the die ( 2, 2 ') and the bending punch (4, 4'), the pivoting element (3, 3 ') is pivoted due to contact with the clamping section (5, 5', 5 ") of the sheet (6 , 6 ', 6 ", 6"') and by folding the pivoting element (3, 3 ') a bending section (7, 7', 7 ", 7" ') of the sheet (6, 6 ', 6 ", 6"') around the bending edge (1, 1 ') of the matrix (2, 2'), the matrix (2, 2 ') presenting a bending edge (1, 1') with a notch (14 ') that runs along the bending edge (1, 1').

Description

Bending procedure and bending device

The present invention relates to a bending process and a bending device with a bending punch and a die having a bending edge. An application of the folding procedure is also the object of the invention.

It is known to join the plates to structural elements by folding. In this regard, the edges of the sheets are folded approximately 180º around corresponding highlights of the structural elements. In conventional procedures, it is necessary to first bend the edges of the sheets by approximately 90 ° and then fold them in the following, for example, at 120 ° to 135 °, before the sheets can be fixedly attached to the structural element by the actual 180 ° folding approximately. In any case, at least three stages of work are needed to create a folding joint. In addition, two different tools are needed for the edge bending stage and the pre-folding stage. The plates do not necessarily have to be attached to a structural element during folding. Folding can also be used to make edges of less sharp components with a correspondingly reduced risk of injury.

Document DE10223637B4 proposes a procedure that allows the plates to be doubled, that is, to bend the edges at an angle greater than 90 °. In this way, an elastic recovery must be countered first at an angle of less than 90 °. However, the device proposed in this regard is characterized by a very complex construction. From JP5305342A, a bending process is known, in which when a matrix having a bending edge and a bending punch having a pivoting element is approaching, the pivoting element is brought into contact with a clamping section of a arranged sheet Between the die and the bending punch, the pivoting element is pivoted and due to the pivoting movement of the pivoting element a bending section of the sheet is folded around the bending edge of the die.

From JP5305342A, a bending device with a bending punch and with a die having a bending edge is also known, the bending punch having a pivoting element, pivotally mounted, with a contact section and a forming section. , the pivoting element can be pivoted and the bending section of the sheet can be folded, which is to be folded, around the bending edge of the die as the forming section can be exerted by the pivoting movement a force on the bending section of the sheet to be folded which has a component located at an angle to the bending edge in the plane of the clamping section.

Based on this, the present invention has the objective of providing a bending process that allows for the safe manufacturing of sheet metal elements with over-folded sections, while keeping installation costs and costs low. In addition, a bending device that allows the folding procedure to be executed must be provided. Finally, an advantageous application of the bending procedure must be provided.

According to a first instruction of the invention, the objective in relation to the procedure is achieved by a bending procedure according to claim 1.

The approach movement can be guaranteed by a movement of the bending punch with respect to a fixed die or a movement of the die with respect to a fixed bending punch. It is also possible to move both the matrix and the bending punch relatively together.

It has been found that with the process according to the invention a very smooth forming of the sheet is possible, despite the relative linear movement of the die and the bending punch, thus reducing the risk of cracking during bending. The method according to the invention also makes it possible above all greater bending angles in one operation.

A first configuration provides that a contact section of the pivoting element is brought into contact with the clamping section of the sheet and that, by means of the pivoting movement of the pivoting element, a force is exerted with a forming section of the pivoting element on the bending section of the sheet having a component located at an angle to the bending edge in the plane of the clamping section. In this way, the available force can be used to form the sheet. This force acts at a more favorable angle in the bending section and thus allows a softer shape of the bending section. In the extreme case it is also possible to exert the force on the bending section of the sheet exclusively in a direction located at an angle with respect to the bending edge in the plane of the clamping section.

In another variant of the bending procedure, the contact section of the pivoting element rolls over the clamping section of the sheet during bending. Through the rolling movement, scratches or pressure points on the surface of the clamping section can be avoided. Therefore, the bending process also allows bending of sheets with a very sensitive surface, for example, lacquered, chromed and / or very bright. According to another configuration, the sheet is held in the die by a treadmill during bending. In this way

a movement of the sheet can be prevented during the forming process, which allows to improve the dimensional stability of the folded sheet.

The procedure can be further refined by bending the sheet bending section at a bending angle greater than 90 °, greater than 105 °, greater than 120 °, up to 135 ° around the bending edge. In the case of a bending angle greater than 90º, sheet metal parts with vertically bent edges can also be made available as it is a sheet material that is elastically recovered. Bending at a bending angle greater than 105 ° makes it possible in a particularly simple manner to arrange a structural element at the acute angle formed of 75 ° and to join it to the sheet by folding. A bending angle greater than 120 ° allows the following folding to be simplified clearly with a slight limitation of the mounting space necessary to provide a structural element. If the bending angle is limited to less than 135 °, the force necessary for bending can be limited to a practical extent.

In another variant of the process, a composite sheet, a solid sheet or a light sheet is bent.

Composite sheets are multilayer sheets, in which at least two layers are made of different materials. Usually, for example, plastic layers are combined with metal layers. The composite sheets allow a weight saving with the same thickness compared to a solid sheet.

As composite sheets, in particular those sheets made from two outer covering sheets, for example, steel, and a plastic layer that joins them are taken into account. The thickness of the veneer sheets is, for example, from 0.30 to 2.00 mm and the thickness of the plastic layer is, for example, from 0.05 to 1.5 mm. This type of composite sheet is characterized by a particularly high damping of the sound produced by solid bodies. As light plates are identified those composite sheets that are made of very thin sheets, for example, of steel, which include a plastic layer. The thicknesses of the steel sheets are from 0.1 mm to 0.3 mm. As a core layer, for example, a layer, for example, of thermoplastic plastic with a thickness of 0.05 mm to 1.5 mm can be provided. Thermoplastic plastic is characterized not only by a good forming capacity, in particular at higher temperatures, but can also clearly simplify the fabrication of the light sheet. The advantages of a light sheet lie mainly in the weight, while maintaining a very good rigidity.

By using a solid sheet, very high flexural stiffness can be achieved with the same material thickness.

A variant further provides that after bending the sheet bending section at a first bending angle, the sheet bending section bends backwards at a second angle. This allows at least partially reducing the stresses produced in the sheet due to the bending process. In particular, delayed delamination can be counteracted in the transition zone of the clamping section and the bending section of a composite sheet. A delayed delamination means an undesirable separation of the inner cover sheet and / or the outer cover sheet from the composite sheet with respect to the plastic layer that joins the inner cover sheet and the outer cover sheet, what does not have to occur directly during bending, but can also occur only after a certain time.

A configuration of the bending procedure further provides for the sheet to fold. The folding allows, on the one hand, to manufacture from the sheet components with rounded edges that reduce the risk of injury. On the other hand, the folding allows the sheet to be joined in a particularly simple manner to other sheets and / or structural elements, without the need for special joining means, such as rivets, adhesives or welds. Consequently, the costs and working time invested in the manufacture of sheet metal components can continue to be reduced.

According to a second instruction of the invention, the objective mentioned above in relation to the device is achieved by a bending device according to claim 9.

The device allows to take better advantage of the force available for forming the sheet. This force can act at a more favorable angle in the bending section to be folded, so that a softer shape can be guaranteed.

A first configuration provides that the contact section and the forming section of the pivoting element are rigidly joined together. The rigid joint enables a particularly simple construction of the device and, therefore, an economical device. In addition, the rigid connection between the contact section and the forming section allows the reliability of the device and, therefore, the safety of the bending process process to continue to increase.

The device can be further refined by mounting the pivoting element with a pivot shaft in the bending punch. This enables a particularly simple construction of the bending device. It is possible to arrange the pivot axis in a fixed or mobile way with respect to the bending punch. A pivot shaft arranged from

movable way allows a simple construction of the bending punch stamp, since it executes only a vertical movement. The pivot axis fixedly arranged in the bending punch simplifies, on the contrary, the construction of the bending punch itself.

Another variant provides that the contact section of the pivoting element can roll on the sheet, which is to be folded, as the pivot axis can move in the bending punch in the radial direction and the pivot element can be guided by a guide element, particularly in its outer contour. This configuration of the bending device enables a bending process that particularly protects the surface, so that sheets with sensitive surfaces can also be bent.

If the pivot axis is oriented parallel to the bending edge in another configuration, the bending section of the sheet can be folded at the same time in its entire width.

The device can also be configured so that the bending device has a treadmill. This allows to fix exactly the clamping section of a sheet to be folded and thus achieve a particularly high dimensional stability with respect to the folded sheet.

The bending edge of the die is provided with a notch that runs along the bending edge. During bending, a pressure application on the inner side of the sheet and a corresponding tensile request on the outer side of the sheet necessarily occur. In the notch, sheet material can be accommodated and thus reduce stress and pressure stresses. Consequently, the danger of cracking on the outer side can be further reduced. Thus, for example, in the notch material of the inner cover sheet material of a composite sheet can be housed in the transition zone of the clamping section to the bending section and a delamination can occur in this area between the sheet metal inner coating and the plastic layer and / or between the plastic layer and the outer coating layer and the plastic layer. In this way, the risk of fissures in the outer covering sheet during the folding of composite sheets can be reduced.

The bending device can be further refined by being able to replace the bending edge of the die. The bending device can thus be easily adapted to different bending radii and different bending angles. In this way, in the same bending device, both bending edges can be used with a notch, which runs along the bending edge, and bending edges that do not have such a notch.

The objective mentioned above in relation to the application is achieved by using the bending process to manufacture a vehicle element, in particular a front wall element and / or an engine bonnet element.

The invention is explained in detail below by means of a drawing in reference to embodiments. The drawing shows:

Fig. 1 a schematic representation of a first embodiment of a device in different positions, which does not fall within the scope of protection of the claims;

Fig. 2 a schematic representation of a second embodiment of a device, according to the invention, in different positions;

Fig. 3 an exemplary embodiment of an application, according to the invention, of the bending process; Y

Fig. 4 a schematic representation to explain another optional stage of the bending procedure.

An exemplary embodiment of a bending device with a bending punch 4 and a die 2 is shown in Figure 1. The bending punch 4 has a pivoting element 3 with a contact section 8 and a forming section 9 rigidly joined to contact section 8. Figure 1a shows the state of the bending device at the beginning of the bending procedure. A sheet 6 is fastened with its clamping section 5 by means of a treadmill 10 in the matrix 2 such that it protrudes laterally with its bending section 7 of the replaceable bending edge 1 of the matrix 2. In the case of the sheet shown 6 It is a solid sheet 6.

As the die 2 and the bending punch 4 approach, the contact section 8 of the pivoting element 3 is brought into contact with the clamping section 5 of the sheet 6 and the pivoting element 3 is pivoted. As a result of the pivoting movement of the element pivoting 3, the bending section 7 of the sheet 6 bends at a bending angle! 130º around the bending edge 1 of the matrix 2.

The pivoting element 3 is mounted on the bending punch 4 with a pivot axis 11. The pivot axis 11 is oriented here parallel to the bending edge 1. During pivoting of the pivoting element 3, the pivoting axis 11 can be move on bending punch 4 in radial direction. In this regard, the pivot element 3 is guided with a guide element 12, so that the contact section 8 of the pivot element 3 can roll on the clamping section 5 of the sheet 6. The surface of the clamping section 5 of sheet 6 is thus protected during bending. In the example of

shown, the guide element 12, whereby the rotational movement of the pivoting element 3 is coupled to the translational movement of the pivot axis 11, is configured as a stop that interacts with the outer contour 14 of the pivoting element 3. In principle, Other types of coupling are also possible, for example, by cogwheels and zippers.

However, the pivot axis 11, as indicated by dashed lines in Figure 1a, can also be fixedly arranged with respect to the bending punch 4 and in this way a bending device with a high rigidity can be made available.

Figure 2 shows the same bending device of Figure 1, in which the die 2 'has, however, according to the invention a bending edge 1' with a notch 14 'which runs along the bending edge 1 '. The technical effect of this notch 14 'during bending is explained by means of a composite sheet 6'.

The outer covering plates 16 ', 17' of the composite sheet 6 'are made of a steel sheet with a thickness of 40 ∀m and are joined together by a layer 18' of 25 ∀m which is made of a plastic viscoelastic

When the composite sheet 6 ’bends, material from the inner covering sheet 16’ can flow from the composite sheet 6 ’to the recess 14’. This causes a delamination in the transition zone of the clamping section 5 ’and the folding section 7’. In other words, the inner cover sheet 16 ’is separated from the plastic layer 18’, whereby it was attached to the outer cover sheet 17 ’. Due to the entry of material into the groove 14 ', the tensile stress of the outer covering sheet 17' is reduced and, consequently, the risk of cracks in the outer covering sheet 17 'after bending. This is particularly important if the folding of the composite sheet 6 ’is then carried out.

An application, according to the invention, of the claimed bending process is explained in Figure 3. This shows a section of a vehicle element 15 "in the form of an engine hood having a composite sheet 6" and a structural element 19 " . The bending section 7 "of the composite sheet 6" was first folded at a bending angle greater than 90 ° in correspondence with the procedure shown in Figure 2 and the inner covering sheet 16 "was separated from the plastic layer 18" by delamination in the transition zone of the clamping section 5 "and the folding section 7". In the acute angle formed of the composite sheet 6 "a structural element 19" was then arranged and by the following folding of the composite sheet 6 ", it was fixedly attached to the structural element 19". The outer covering sheet 17 "also does not show cracks after 180º folding.

Figure 4 shows a device that allows a bending section 7 "'of a sheet 6"' to be folded back at a bend angle # "', which is folded, for example, with the bending device shown in figure 1 at a bending angle! ” In this case it is a 6 ”’ composite sheet. To this end, the device has a 20 "frame" that predefines the angle "", in which the bending section 7 "of the sheet 6" must be folded back. The frame 20 "’ serves here simultaneously to hold the sheet 6 "’ on the machine table 21 "’. However, it is basically possible also to provide for these two functions respectively a device element of its own. A 22 ”’ punch is also provided, with which the necessary force is applied for bending in sheet 6 ”’. The punch 22 "’ is operated here hydraulically or pneumatically. For this purpose it is also possible to provide an electric motor, for example, a linear motor.

Bending backwards at the bending angle # "’ tensions, resulting from bending, are compensated between the inner cover sheet 16 "’ and the outer cover sheet 17 "’. Consequently, the 6 "sheet machined in this way is characterized by a clearly minor tendency to delayed delamination in the bending zone.

Claims (16)

one.

Bending procedure, in which when approaching a matrix (2, 2 ') that has a bending edge (1, 1') and a bending punch (4, 4 ') that has a pivoting element (3, 3' ), the pivoting element (3, 3 ') is brought into contact with a clamping section (5, 5', 5 ") of a sheet (6, 6 ', 6", 6 "') arranged between the die ( 2, 2 ') and the bending punch (4, 4'), the pivoting element (3, 3 ') is pivoted due to contact with the clamping section (5, 5', 5 ”) of the sheet (6 , 6 ', 6 ", 6"') and by folding the pivoting element (3, 3 ') a bending section (7, 7', 7 ", 7" ') of the sheet (6, 6 ', 6 ", 6"') around the bending edge (1, 1 ') of the matrix (2, 2'), the matrix (2, 2 ') presenting a bending edge (1, 1') with a notch (14 ') that runs along the bending edge (1, 1').

2.

Bending process according to claim 1, characterized in that a contact section (8) of the pivoting element (3, 3 ') is brought into contact with the clamping section (5, 5', 5 ") of the sheet (6, 6 ', 6 ", 6"') and by means of the pivoting movement of the pivoting element (3, 3 ') a force is exerted with a forming section (9) of the pivoting element (3, 3') on the bending section (7, 7 ', 7 ", 7"') of the sheet (6, 6 ', 6 ", 6"'), which has a component located at an angle to the bending edge (1, 1 ') in the plane of the clamping section (5, 5', 5 ”).

3.

Bending process according to one of claims 1 or 2, characterized in that the contact section (8) of the pivoting element (3, 3 ') is rolled over the clamping section (5, 5', 5 ”) of the sheet (6, 6 ', 6 ", 6"') during bending.

Four.

Bending process according to one of claims 1 to 3, characterized in that the sheet (6, 6 ', 6 ", 6"') is held in the die (2, 2 ') by a treadmill (10) during the folded.

5.

Bending process according to one of claims 1 to 4, characterized in that the bending section (7, 7 ', 7 ", 7"') of the sheet (6, 6 ', 6 ", 6"') it bends at a bend angle (!,! ”) greater than 90 °, greater than 105 °, greater than 120 °, up to 135 ° around the bending edge (1, 1 ') of the matrix (2, 2').

6.

Bending process according to one of claims 1 to 5, characterized in that a composite sheet, a solid sheet (6, 6 ’, 6”, 6 ”’) or a light sheet is bent.

7.

Bending process according to one of claims 1 to 6, characterized in that after bending the bending section (7, 7 ', 7 ", 7"') of the sheet (6, 6 ', 6 ", 6 "') At a first bending angle (!,!"'), The bending section (7, 7 ', 7 ", 7"') of the sheet (6, 6 ', 6 ", 6"') it bends backwards at a second angle (# "').

8.

Bending process according to one of claims 1 to 7, characterized in that the sheet is folded (6, 6 ’, 6”, 6 ”’).

9.

Bending device for executing a method according to one of claims 1 to 8, with a bending punch (4, 4 ') and a die (2, 2') having a bending edge (1, 1 ') , characterized in that the bending punch (4, 4 ') has a pivoting element (3, 3'), pivotally mounted, with a contact section (8) and a forming section (9), the pivoting element (3, 3 ') can be pivoted due to the contact of the contact section (8) with a clamping section (5, 5', 5 ") of a bending plate (6, 6 ', 6", 6 " ') and the bending section (7, 7', 7 ", 7" ') of the sheet to be folded (6, 6', 6 ", 6" ') can be folded around the bending edge (1, 1 ') of the die (2, 2') to be able to exert the forming section (9) by means of the pivoting movement a force on the bending section (7, 7 ', 7 ", 7"') of the sheet to be folded (6, 6 ', 6 ", 6"'), which has a component located in á angle with respect to the bending edge (1, 1 ') in the plane of the clamping section (5, 5', 5 "), the matrix (2, 2 ') presenting a bending edge (1, 1') with a notch (14 ') that runs along the bending edge (1, 1').

10.

Bending device according to claim 9, characterized in that the contact section (8) and the forming section (9) of the pivoting element (3, 3 ’) are rigidly joined together.

eleven.

Folding device according to one of claims 9 or 10, characterized in that the pivoting element (3, 3 ’) is mounted with a pivot shaft (11) on the bending punch (4, 4’).

12.

Bending device according to one of claims 9 to 11, characterized in that the contact section (8) of the pivoting element (3, 3 ') can roll on the sheet to be folded (6, 6', 6 ", 6 "') When the pivot axis (11) can be moved in the bending punch (4, 4') in the radial direction and the pivot element (3, 3 ') can be guided by a guide element (12), in particular in its outer contour (13).

13.

Bending device according to one of claims 9 to 12, characterized in that the pivot axis (11) is oriented parallel to the bending edge (1, 1 ’).

14.

Folding device according to one of claims 9 to 13, characterized in that the folding device has a treadmill (10).

fifteen.

Bending device according to one of claims 9 to 14, characterized in that the bending edge (1, 1 ’) of the die (2, 2’) can be replaced.

16.

Use of a bending method according to one of claims 1 to 8 for manufacturing a vehicle element (15 "), in particular a front wall element and / or an engine bonnet element.