Method and system for manufacturing longitudinal frame members for utility vehicles

Abstract

In the method according to the invention for manufacturing longitudinal frame members for utility vehicles, at least one forming process and at least one punching process are used, wherein, in the punching process, a hole pattern consisting of a large number of holes is punched and at least two series of longitudinal frame members are manufactured which differ from one another at least in terms of their hole pattern. A hole-group punching apparatus having a large number of punches is used for punching at least a majority of the holes of the longitudinal frame member hole pattern to be punched, wherein the punches are individually activated or deactivated for each punching procedure depending on the hole pattern to be produced such that, during each punching procedure, a number of holes corresponding to the number of activated punches are punched simultaneously and the majority or all of the holes of the longitudinal frame member hole pattern to be punched are produced by a large number of punching procedures of the hole-group punching apparatus.

Description

[0001] The invention relates to a method and a system for manufacturing frame longitudinal members for commercial vehicles.

[0002] Frame longitudinal members are a core component of truck frames and are typically produced in a forming machine as a U-shaped profile from a sheet metal strip or, alternatively, from a sheet metal blank. They can be designed in straight or angled versions. For attaching cross members, stiffeners, bracing plates, and the like, the frame longitudinal members are also provided with a hole pattern consisting of numerous holes, specified by the vehicle manufacturer.

[0003] The hole pattern is conventionally created using large punching presses that allow for the simultaneous punching of all holes in the frame's longitudinal beam. Simultaneous punching offers a significant advantage over single-hole punching: the punching process can be carried out very quickly, and the overall manufacturing process is not hindered by the punching operation in terms of the total cycle time. Single-hole punching requires considerably more time, often necessitating the parallel operation of multiple single-hole punches. However, single-hole punches have the advantage of being quickly adaptable to a different hole pattern. With large punches that produce the entire hole pattern in a single pass, this is associated with significantly longer changeover times and considerable tooling costs.

[0004] From JP 4 714425 B2 a method and a system for producing stamped, U-shaped profiles according to the preamble of claims 1 and 11 is known, wherein a hole group punching device is used with which a number of holes corresponding to the number of activated punch dies is punched simultaneously in each punching operation.

[0005] Punching units for hole groups are also known from EP 0 658 383 A1, DE 41 28 194 A1, JP H06 210366 A and JP 2002 113530 A.

[0006] The invention is based on the objective of providing a method for manufacturing frame longitudinal members, which is characterized, on the one hand, by a rapidly executable punching process with potentially varying hole spacing in the longitudinal direction of the component, and, on the other hand, by a short changeover time when dealing with changing hole diameters and hole spacings in the width direction of the component. The objective also relates to a system for carrying out the method.

[0007] According to the invention, this problem is solved by the features of claims 1 and 11.

[0008] In the inventive method for manufacturing frame longitudinal members for commercial vehicles, at least one forming process is used, in which a U-shaped profile is produced from a sheet metal strip or from a sheet metal blank, and at least one stamping process is used, wherein in the stamping process a hole pattern consisting of a plurality of holes is stamped and at least two series of frame longitudinal members are produced, which differ from each other at least by their hole pattern.To punch at least a large part of the holes of the hole pattern to be punched in the frame longitudinal member, a hole group punching device with a plurality of punching dies is used, wherein the punching dies are individually activated or deactivated in each punching operation depending on the hole pattern to be produced, so that in each punching operation a number of holes corresponding to the number of activated punching dies is punched simultaneously and the majority or all of the holes of the hole pattern to be punched in the frame longitudinal member are produced by a plurality of punching operations of the hole group punching device and wherein, before or after the punching of the holes in the hole group punching device, at least one further separating or cutting process is carried out by means of a single hole punch to produce at least one further closed contour to complete the hole pattern to be punched.

[0009] In the inventive system for the production of at least two series of frame longitudinal members for commercial vehicles, a forming device for producing a U-shaped profile from a sheet metal strip or sheet metal blank and at least one punching device for punching a hole pattern consisting of a plurality of holes are provided, wherein the at least two series of frame longitudinal members differ from each other at least by their hole pattern.The at least one punching device is formed by a hole group punching device with a plurality of punching dies, wherein the punching dies can be individually activated or deactivated by means of an activation unit in each punching operation depending on the hole pattern to be produced, so that in each punching operation a number of holes corresponding to the number of activated punching dies is punched simultaneously, wherein the plurality of punching dies is arranged such that at least a large proportion of the holes of the hole pattern to be punched can be produced by a plurality of punching operations.Furthermore, a separating or cutting device in the form of a single-hole punch is provided upstream or downstream of the hole group punching device to generate at least one further closed contour, so that the hole pattern to be punched consists of holes of the hole group punching device and the at least one further closed contour of the separating or cutting device.

[0010] The considerations underlying the invention revealed that a multitude of holes are arranged on parallel straight lines running lengthwise along the frame's longitudinal members, the so-called hole tracks. The holes located on these hole tracks are preferably punched by the hole group punching device, whereby several holes can optionally be punched simultaneously. While the hole group punching device cannot punch all holes of a hole pattern in a single operation, the punching process is significantly shortened compared to a punching process using only a single-hole punch, since the punching dies only need to be activated or deactivated for each punching operation and do not need to be positioned transversely to the component. This allows for individualization of the hole pattern.

[0011] If another series of frame longitudinal members needs to be produced, which differs from the previously produced frame longitudinal member at least in its hole pattern, this can potentially be done with the same hole punching unit, provided the hole patterns are spaced the same and the same punches are usable with respect to their diameter. Should the hole pattern spacing or the punches not be compatible, the hole punching unit can be quickly reconfigured due to the manageable number of punches. Preferably, the hole punching unit uses 5 to 20 punches.

[0012] In the forming process, the U-shaped profile is produced primarily by roll forming or die bending. The U-shaped profile can have a material thickness of 4 mm to 12 mm, although it is also conceivable that the material thickness varies along the sheet's length and / or width, resulting in a formed U-profile with a non-constant thickness in either direction. This allows for the reinforcement of certain areas while saving material and thus weight in other areas.

[0013] The hole group punching device preferably operates as a mechanical hole group punching device with a stroke frequency of at least 50, preferably at least 100, and most preferably at least 140 strokes per minute, thereby enabling the punching process to be carried out at high speed. Furthermore, the hole group punching device can be designed such that at least 70%, preferably at least 80%, and most preferably at least 90% of all holes in the hole pattern to be punched can be punched with it.

[0014] The further separation or cutting process to produce at least one further closed contour is carried out by a single die and is intended in particular for those contours that do not lie on one of the hole tracks or have a rarely occurring shape or size.

[0015] It is further stipulated that each hole pattern is generated based on a control data set, which assigns all holes that can be punched with the hole group punching unit to the punching process with the hole group punching unit and the remaining holes to the subsequent separating or cutting process. During each punching operation of the hole group punching unit, a longitudinal section of the hole pattern to be punched is punched, whereby the holes to be punched in each longitudinal section are stored in the control data set, and the punching dies are individually activated or deactivated during each punching operation using the control data set. The hole group punching unit punches all holes assigned to it within a longitudinal section of the hole pattern to be punched during each punching operation, and the position of the hole group in the subsequent longitudinal section is set by controlled feed.

[0016] In the method according to the invention, a plurality of holes adjacent to each other in the longitudinal direction of the frame member and / or a plurality of holes adjacent to each other in the transverse direction of the frame member can have different spacings from one another. Furthermore, it is conceivable that holes with different diameters are punched on at least one of the hole patterns. In this way, a wide variety of hole patterns can be produced to meet the respective requirements.

[0017] To ensure that the holes to be punched are placed in the component at precisely the correct position, a further embodiment of the invention provides that the position of the component relative to the hole-punching device is determined by a measuring device, and any misalignment is corrected by a positioning unit transverse to the strip feed direction. The position can be measured, in particular, by means of two sensors on each side of the component to be punched, resulting in increased flexibility, since the hole pattern to be created can be aligned with the left or right edge of the component in the sheet feed direction, as well as with the center of the component. For example, displacement sensors can be used as sensors, based, for instance, on changes in resistance, variable inductance, variable capacitance, pulse counting, transit-time measurement, or triangulation.

[0018] Furthermore, the position of the component relative to the punching unit can be corrected as a function of measurement by means of at least one positioning unit transverse to the feed direction. The positioning unit moves translationally and can be designed, for example, as a linear unit with a ball screw drive or toothed belt drive, as a wedge mechanism, as an eccentric, or as a comparable system to achieve a defined, linear path difference.

[0019] Furthermore, an automated inspection can be performed after the punching process to detect whether the holes to be punched are actually present. This inspection can be carried out, for example, using camera detection, transmitted light methods, inductive, capacitive, or mechanical sensors.

[0020] In principle, the forming process and the at least one punching process can be carried out in any order. However, to increase the dimensional accuracy of the holes to be punched, it is more advantageous to perform the forming process first and then the at least one punching process.

[0021] According to a further embodiment of the invention, the punching unit comprises at least one tool unit, each consisting of an upper tool part and a lower tool part. The upper tool part, in turn, has an activation bar and a punch bar, and the lower tool part is composed of a die bar and a waste bar. The activation bar serves to activate or deactivate the individual punches guided in the punch bar. Particularly high system flexibility can be achieved by having the activation units have a greater width than the punches, allowing for a slight change in the hole pattern position in the width direction simply by replacing the punch bar and the die bar.Furthermore, if the number of punch tracks changes or the punch track position changes significantly, both the activation and punch strip as well as the matrix and waste strip can be exchanged.

[0022] Further embodiments of the invention are explained in more detail with reference to the following description and the drawing.

[0023] The drawing shows Fig. 1 a block diagram of a system according to the invention for the production of frame longitudinal members according to a first embodiment, Fig. 2 a block diagram of a system according to the invention for the production of frame longitudinal members according to a second embodiment, Fig. 3 a schematic representation of the forming process by means of roll forming, Fig. 4 a schematic representation of the forming process by means of die bending, Figs. 5a - 5c different cross-sections of the U-shaped profile of the frame longitudinal member, Fig. 6 representation of the hole pattern in a longitudinal section of the frame longitudinal member, Figs. 7a + 7b representation of the hole group punching device with activated punches at different times, Figs. 8a + 8b top view and sectional view of a positioning unit according to a first embodiment, Figs. 9a + 9b top view and sectional view of a positioning unit according to a second embodiment, Fig.Fig. 10a + 10b Top view and sectional view of a positioning unit according to a third embodiment, Fig. 11a + 11b Top view and sectional view of a positioning unit according to a fourth embodiment, Fig. 12a + 12b Top view and sectional view in the area of ​​the punching unit at a first point in time, Fig. 13a + 13b Top view and sectional view in the area of ​​the punching unit at a second point in time, Fig. 14a + 14b Representations of a punch activation according to a first embodiment, Fig. 15a + 15b Representations of a punch activation according to a second embodiment, Fig. 16 A schematic block diagram of the system in the area of ​​the punching unit, Fig. 17 A sectional view of the punching unit with two activated punches, Fig. 18 A sectional view of the punching unit with one activated punch.19 Sectional view along line HH of the . Fig. 18 in the area of ​​the slide bar and Fig. 20a + 20b sectional views of the hole group punching device with two different punch bars.

[0024] The inventive system for manufacturing frame longitudinal members for commercial vehicles comprises a forming device 1, a punching device 2, and a cutting or separating device 3 for producing at least one further closed contour. The forming device 1, the punching device 2, and the cutting or separating device 3 are formed by separate modules, which can be arranged in any order relative to one another. The illustrations differ accordingly. Fig. 1 und Fig. 2 by reversing the positions of the hole-group punching device 2 and the separating or cutting device 3. Although it is conceivable to perform the forming process at the end of the process chain, it is more advantageous for increasing the dimensional stability of the holes to be punched if the forming process is carried out first in the forming device 1 and only then the punching process. Within the scope of the invention, it is also conceivable that only the hole-group punching device 2 is used for the punching process. This would be particularly possible if all the holes to be punched were arranged on a manageable number of hole tracks (straight lines) running in the longitudinal direction of the frame member.

[0025] In the forming process, a U-shaped profile 4 is produced from a sheet metal strip 5a or sheet metal blank 5b. For this purpose, the in Fig. 3 depicted roll forming or die bending according to Fig. 4 The U-shaped profile 4 can have a material thickness of 4–12 mm, and it is also conceivable that the material thickness varies in different areas along the sheet's longitudinal and / or width directions, as exemplified by the figures in the Fig. 5a, 5b und 5c The longitudinal sections shown have different wall thicknesses (d 1 , d 2 , d 3 , d 4 ).

[0026] Fig. 6 Figure 4 is a finished, punched longitudinal section of the U-shaped profile 4, showing that a plurality of punched holes 7a, 7b are arranged on parallel hole tracks 6a, 6b, 6c running lengthwise along the U-shaped profile. The holes arranged on the hole tracks 6a-6c can differ, in particular, in their diameter. For example, holes 7a have a larger diameter than holes 7b. Furthermore, the distance between adjacent holes can also vary both longitudinally and transversely along the frame member. In the illustrated embodiment, the three hole tracks are spaced apart from each other by a distance Δy 1.While holes 7a and 7b are expediently produced using the hole group punching device 2, the holes 8a, 8b, and 8c, which lie outside the hole tracks 6a-6c, are produced using the separating or cutting device 3, which is designed, for example, as a conventional single-hole punch. With the aid of the two punching devices, the punched holes 7a, 7b, 8a, 8b, and 8c can be arranged both transversely and longitudinally along the frame member with equal or different spacings (Δy₁, Δy₂, Δx₁, Δx₂), resulting in highly flexible hole patterns.

[0027] The in the Fig. 7a und Fig. 7b The depicted hole group punching device 2 has a plurality of punching dies 9, which are individually activated or deactivated during each punching operation depending on the hole pattern to be produced, so that a number of holes corresponding to the number of activated punching dies are punched simultaneously in each punching operation. The majority or all of the holes of the hole pattern to be punched in the frame longitudinal member can thus be produced with a plurality of punching operations of the hole group punching device 2. The hole group punching device 2 according to Fig. 7a und Fig. 7b has thirteen punch dies 9, including the one in Fig. 7a At the depicted time, five die-cutting stamps 9 are activated. The activated die-cutting stamps 9 are represented by solid lines, and the deactivated die-cutting stamps by dotted lines. At another, in Fig. 7b At the time shown, for example, four of the nine punch dies are activated, while the others are deactivated.

[0028] In order to ensure that the holes to be punched are placed in exactly the correct position in the U-shaped profile 4, the position of the component relative to the hole group punching device 2 is determined by a measuring device which includes, for example, one or more sensors 10a-10d ( Fig. 8a, 8b Misalignment can then be corrected using positioning units 11a-11d. In the illustrated embodiment, the positioning units 11a-11d each have two rollers 12a, 12b which engage the legs of the U-shaped profile. To position the U-shaped profile 4, these rollers 12a, 12b are moved, for example, translationally using a linear unit 13. The other positioning units 11a, 11b, 11d can be designed in a similar manner.

[0029] In Fig. 9a und Fig. 9b A second embodiment is shown in which the U-shaped profile 4 can be positioned using only one positioning unit 14. The position of the U-shaped profile 4 is again determined by means of several sensors 10a-10d. The positioning unit 14 has two positioning units 14a, 14b, which are in rolling contact on the outside of the legs 4a, 4d of the U-shaped profile 4 and are adjustable transversely to the longitudinal extent of the U-shaped profile via a linear unit 15. Fig. 10a und Fig. 10b A third embodiment is shown, which differs from the embodiment according to the Fig. 9a und Fig. 9b The only difference is that, in addition to the positioning unit 14, a further positioning unit 16 is provided, with one of the two positioning units being arranged in the conveying device of the U-shaped profile 4 upstream and one positioning unit downstream of the hole group punching device 2, so that extremely precise alignment of the U-shaped profile 4 can be achieved. Fig. 11a und Fig. 11b Finally, a fourth embodiment is shown, in which four positioning units 17a-17d are used, each equipped with separately controllable drives for aligning the U-shaped profile 4. Two positioning units are arranged opposite each other, with two being located before and two after the punching unit 2.

[0030] Fig. 12a Figure 1 illustrates a punching operation at time t1, at which six of the eleven punching dies of the punching unit 2 are activated. Section EE according to... Fig. 12b Three activated punch dies 9a, 9b, 9c are visible immediately before the punching process. Fig. 13a The situation at a subsequent time point t2 is shown, where only three punch dies are activated. In the section view FF according to... Fig. 13b For example, only the 9c die stamp is activated.

[0031] The activation or deactivation of the punch dies 9 can be carried out via any suitable activation unit 18. In the Fig. 14a und Fig. 14b The activation unit 18 is implemented by a wedge mechanism 18a, which can be actuated via a translational traversing unit 19 to activate / deactivate a punch 9. The punch is reset, for example, by a spring element 20. In the exemplary embodiment according to the Fig. 15a und Fig. 15b The activation unit is implemented by means of sliding plates 18b. Of course, other activation units are also conceivable within the scope of the invention.

[0032] Based on the block diagram according to Fig. 16 The following section explains in more detail the data flow for implementing the punching process using the hole group punching unit 2. The punching process of the hole group punching unit 2 is controlled by a central unit 21, which also stores the hole pattern to be punched as a data record. The feed of the U-shaped profile 4 is longitudinal and is controlled by a feed control unit 22. The alignment of the U-shaped profile 4 transversely to the feed direction 26 is controlled by a positioning control unit 23, which communicates with the sensors (e.g., 10b and 10c) and the positioning units (e.g., 17a-17d). The activation or deactivation of the individual punches of the hole group punching unit 2 is controlled by the punch control unit 24, depending on the stored control data record of the hole pattern to be generated. The actual punching process is then triggered by the press control unit 25.

[0033] Based on the Fig. 17 bis Fig. 20b The structure and operation of the hole-group punching device 2 are explained in more detail. It essentially consists of an upper tool part, which is composed of an activation bar 2.2 and a punch bar 2.3. The corresponding lower tool part has a die bar 2.4 and a waste bar 2.5. The punches 9 are guided in the punch bar 2.3 and are activated or deactivated via activation units 18 in the activation bar 2.2.

[0034] The actual punching process is triggered by a press ram 2.1. The parts punched out by the activated punching dies 9 fall downwards via the waste bar 2.5 and the waste channel 2.6. The movable upper tool part is guided in guides 2.8 relative to the stationary lower tool part and is designed, for example, for stroke frequencies of at least 140 strokes per minute.

[0035] The punching bar 2.3 has several punching dies 9 both in the feed direction 26 of the U-shaped profile 4 and transversely thereto, as can be seen, for example, from Fig. 19 This is evident. The punches are arranged relative to each other and have suitable diameters so that they can produce the majority of the holes required for the entire hole pattern. However, for frame members with a different hole pattern, a different punch bar 2.2 will often be required because, for example, a different spacing of the hole tracks and / or holes with different diameters are required. The activation bar 2.2, on the other hand, is designed so that 18 different punches 9, in particular punches that differ in their diameters, can be activated with one and the same activation unit, as is the case, for example, with the following: Fig. 17 , Fig. 19 and Fig. 20a This is evident. In addition to different diameters of the punches, a change in the position of the punch 9 relative to the activation unit 18 is also possible within a certain range, as shown in Fig. 19 This is made possible by the fact that the activation unit 18 in the activation bar 2.2 has an increased width compared to the punch. This has the further advantage that, when changing over the punch bar 2.3 and the associated die bar 2.4, it may not be necessary to replace the activation bar 2.2, thus reducing changeover times and material costs. At the same time, the effort and costs for tool maintenance are reduced. Fig. 20a und Fig. 20b Two further embodiments are shown, in which only the punch bar 2.3' with associated die bar 2.4' ( Fig. 20a ) or the stamping bar 2.3" and the associated die bar 2.4" ( Fig. 20b) are replaced, while the same activation bar 2.2 and the same waste bar 2.5 are used.

Claims

1. Method for manufacturing longitudinal frame members for utility vehicles with at least one forming process, in which a U-shaped profile (4) is produced from a sheet metal strip (5a) or from a sheet metal blank (5b), and at least one punching process, wherein during the punching process a hole pattern consisting of a plurality of holes (7a, 7b, 8a-8c) is punched and at least two series of longitudinal frame members are manufactured, which differ from one another at least by their hole pattern, wherein a hole group punching device (2) with a plurality of punching dies (9) is used for punching at least a majority of the holes of the hole pattern to be punched of a longitudinal frame member, wherein the punching dies (9) are activated or deactivated individually in each punching process depending on the hole pattern to be produced, so that in each punching process a number of holes (7a, 7b, 8a-8c) corresponding to the number of activated punching dies (9) is punched simultaneously and the majority or the entirety of the holes of the hole pattern to be punched of the longitudinal frame member is produced by a plurality of punching processes of the hole group punching device (2), characterised in that, before or after the punching of the holes (7a, 7b, 8a-8c) in the hole group punching device (2), at least one further separating or cutting process is carried out by means of an individual hole punch to produce at least one further closed contour to complete the hole pattern to be punched.

2. Method according to claim 1, characterised in that the hole group punching device (2) operates as a mechanical hole group punching device (2) with a stroke frequency of at least 50 strokes per minute.

3. Method according to claim 1, characterised in that at least 70%, preferably at least 80%, most preferably at least 90% of all holes (7a, 7b, 8a-8c) of the hole pattern to be punched are punched with the hole group punching device (2).

4. Method according to claim 1, characterised in that each hole pattern is produced on the basis of a control data set that assigns all holes (7a, 7b, 8a-8c) that can be punched with the hole group punching unit (2) to the punching process with the hole group punching unit (2) and the remaining holes to the further separating or cutting process by means of an individual hole punch.

5. Method according to claim 1, characterised in that the U-shaped profile (4) is manufactured during the forming process by roll profiling or die bending.

6. Method according to claim 1, characterised in that a plurality of holes (7a, 7b, 8a-8c) of the punched hole pattern that are adjacent in the longitudinal direction of the longitudinal frame member and / or a plurality of holes that are adjacent in the transverse direction of the longitudinal frame member have different distances from one another.

7. Method according to claim 1, characterised in that all holes (7a, 7b, 8a-8c) produced by the hole group punching device (2) are punched on hole tracks (6a, 6b, 6c) running parallel to one another and extending in a longitudinal direction of the longitudinal frame member.

8. Method according to claim 7, characterised in that holes (7a, 7b, 8a-8c) with different diameters are punched on at least one of the hole tracks (6a, 6b, 6c).

9. Method according to claim 1, characterised in that with each punching process of the hole group punching device (2), a longitudinal section of the hole pattern to be punched is punched and the holes (7a, 7b, 8a-8c) to be punched in each longitudinal section are stored in a control data set, wherein the punching dies (9) are activated or deactivated individually with the help of the control data set in each punching process.

10. Method according to claim 1, characterised in that the hole group punching device (2) punches all holes (7a, 7b, 8a-8c) of a longitudinal section of the hole pattern to be punched that are assigned to the hole group punching device (2) during each punching process and the position of the holes (7a, 7b, 8a-8c) in the subsequent longitudinal section is adjusted by a controlled feed.

11. System for manufacturing at least two series of longitudinal frame members for utility vehicles with a forming device (1) for producing a U-shaped profile (4) from a sheet metal strip (5a) or from a sheet metal blank (5b) and at least one punching device for punching a hole pattern consisting of a plurality of holes (7a, 7b, 8a-8c), wherein the at least two series of longitudinal frame members differ from one another at least by their hole pattern, wherein the at least one punching device is formed by a hole group punching device (2) with a plurality of punching dies (9), wherein the punching dies (9) can be activated or deactivated individually in each punching process depending on the hole pattern to be produced by means of an activation unit (18), so that in each punching process a number of holes (7a, 7b, 8a-8c) corresponding to the number of activated punching dies (9) is punched simultaneously, wherein the plurality of punching dies (9) is arranged such that at least a majority of the holes (7a, 7b, 8a-8c) of the hole pattern to be punched can be produced by a plurality of punching processes, characterised in that a separating or cutting device (3) in the form of an individual hole punch is further provided upstream or downstream of the hole group punching device (2) to produce at least one further closed contour, so that the hole pattern to be punched is composed of holes (7a, 7b, 8a-8c) of the hole group punching device (2) and the at least one individual punch.

12. System according to claim 11, characterised in that the forming device (1), the hole group punching device (2) and the separating or cutting device (3) in the form of an individual punch are formed by separate modules which can be arranged in any desired sequence with respect to one another.

13. System according to claim 11, characterised in that the hole group punching device (2) has at least a first and a second type of punching dies (9) which differ in diameter.

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