RU2259250C1 - Method of and device for bending long shaped blanks - Google Patents

Abstract

FIELD: plastic metal working.

SUBSTANCE: invention can be used for bending and straightening of rolled sections and strips. According to proposed method of bending, blank is moved longitudinally, and bending forces and counteracting forces spaced relative to bending forces are applied square to flange of blank determining outer radius of bending and parallel to its free walls. Hindering forces are applied in place of action of bending force square to free walls of blank to decrease buckling. Device provided with pressure and support deforming members made in form of rollers whose shape corresponds to cross section of parts under bending has slots in pressure roller with widening from roll axis for free walls of blank.

EFFECT: improved quality of product owing to reduced buckling of free walls of section and specific consumption of material and power.

10 cl, 1 tbl, 3 dwg

Description

The invention relates to the processing of metals by pressure, and in particular to universal methods and devices for bending and straightening parts from profiles and strips, as well as profiles obtained by pressing, casting or welding from individual sheet and profile strips.

Known are traditional methods of forming parts from profiled steel using transverse elastic-plastic bending on presses or roller machines (see Kuklin OS, Shabarshin VP Means of technological equipment for case-processing workshops. Part II. - L.: TsNII "Rumb", 1989).

For bending on presses, complex, usually special dies are required for each profile size (see, for example, USSR AS No. 1532142). The same complex multi-stand devices are used in the manufacture of profiles from sheet blanks by profiling. In this case, simultaneously or sequentially bending forces are applied in the longitudinal and transverse directions of the workpiece. Lamellar elements of manufactured profiles due to loss of stability in the field of compressive deformations receive corrugation and other side curvatures, which requires subsequent fine-tuning of parts on press plants and increases the cost of forming processes.

Closest to the claimed technical solution is a method of bending steel profiles according to Europatent (application No. 0093685), adopted as a prototype. In this method, in order to reduce the influence of the loss of stability of the wall of the profile, along with the perpendicular application to the shelf defining the external radius of the profile, a successively moving main bending force is applied in parallel to it at opposing forces at fixed points spaced apart in relation to the bending force. Pressure and back pressure are created in such a way that they cause only compressive force in the profile wall, while the effect of loss of profile stability is reduced.

However, when using the prototype, very high values of bending efforts are required, as well as the need to manufacture complex deforming devices, which increases the capital, material and energy intensity of bending and straightening processes.

In recent years, methods of shaping sheet metal parts using rotational-local deformation (RLD) have been increasingly used, which can significantly (10-90 times) reduce the required bending efforts and improve the technical and economic performance of the forming process (see, for example, RF patents №№2019337, 2102170, 2129929, 2191082, 2194589, 2199407, 2199408, 2194589, 2200639). Previously, similar technological processes were tested when bending individual profiles in special conical rollers (see Tulin V. A. Research and determination of the main parameters of bending profiles in conical rollers. Abstract of the dissertation. - L., TsNIITS, 1970), but not found wide application in industry due to the need for a constant change of deforming equipment.

The objective of the present invention is to achieve significant resource savings in the formation (bending and lapping) of profiled parts by applying universal methods of bending and equipment with a minimum of deforming equipment. The technical result that provides a solution to the problem is to reduce the applied main bending force, as well as reducing the corrugation of the free walls of the profile and undesirable side bending.

The problem is solved as follows.

In the proposed method, moving the profile, to the shelf defining the external radius of the obtained bend, besides the bending force, opposing forces are also spaced apart from it. In addition, to reduce the corrugation of the free walls of the profile at the site of the bending force, an additional constraining force is applied perpendicularly to the free walls of the workpiece.

In special cases of the claimed method, in order to reduce the unwanted side bending of the profile caused by its asymmetry, an additional corrective force is applied at the site of the bending force or after the second counter-force moving along the workpiece, also directed perpendicular to the free walls of the workpiece.

In another particular case, to ensure guaranteed movement of the bent workpiece, additional static or impact forces are applied to its end edge.

In another particular case of the claimed method, to ensure effective straightening of the corrugations obtained by bending the thin walls of the profile, the bending of the profiled workpiece is carried out with a residual bend by the amount of its subsequent extension necessary to straighten the corrugations.

To implement the claimed bending method, a device is proposed whose prototype is the device “Bending rollers for machines with parallel shafts” (E.N. Moshnin. “Bending and dressing on rotary machines”, M., Mechanical Engineering, 1967, p.133, fig. . 58).

The proposed device for bending long profiled blanks contains push and support deforming elements in the form of rollers made in the form of a cross section of bent parts, and for free edges of the profile in the push deforming roller there are grooves that cause a constraining force when the workpiece moves along the roller, in addition, these the grooves are made with the extension from the axis of the roller to prevent jamming of the workpiece when moving along the roller.

In the particular case of the proposed device, the lateral working surfaces of the pressure roller are offset from the interacting surfaces of the support rollers, directed in the opposite direction from the expected side bending, which ensures the occurrence of a corrective force located perpendicular to the bending force.

In another particular case of the proposed device to provide corrective efforts, it can be equipped with a special unit located behind the second supporting roller along the workpiece.

In another particular case of the proposed device for the steady movement of the workpiece by rollers by increasing the torque between the pressure and support rollers, a backing sheet element is installed that bends simultaneously with the workpiece, the spring value of which is greater than the spring of the bent workpiece.

In the last particular case of the proposed device for bending the end edges of the workpiece, an additional plug-in pressing element is used, having a cross-sectional shape of the bent workpiece and a curvature less than that required by the amount of workpiece springing.

The invention is illustrated by the following drawings:

Figure 1 is a longitudinal section of a bending device mounted on the console of a three-roll bending machine;

Figure 2 is a side view of a bending device;

Figure 3 is a side view of a bending device with an additional deforming element for bending the ends of the workpiece.

Pre-profiled blank 1 (Fig.1 and 2) after applying bending forces in the longitudinal direction on a conventional press brake along rectilinear generators with a radius r is bent in the transverse direction by the main bending force P by a radius R in the proposed device. This device is equipped with a pressure roller 2 and two support rollers 3 located on the consoles of the rolls 5 of the bending machine 6 and fixed by bolts 4. The deforming rollers 2 and 3, profiled in the shape of the cross section of the workpiece, provide, in addition to the main bend, the workpiece being constrained by its free walls 7. The grooves for these walls are made with a slope of 8 from the axis of the roller to prevent clamping of free walls and reduce corrugation on their surface.

To prevent side bending of the workpiece 1 in the transverse direction along arrow A with an asymmetric cross section, an amount of A is shifted in the direction opposite to the expected side bending of the side working surfaces 8 of the pressure roller 2 from the interacting surfaces 9 of the support rollers 3, thereby creating a corrective force P _box This corrective force can also be applied to the output end of the workpiece in a plane perpendicular to the plane of the main bend, for example, using a special unit.

When jamming the workpiece 1 in the slots of the pressure plate 2 and the supporting 3 rollers, in order to increase the torque, underlay sheets 10 or similar blanks 11 are installed between the work rolls 5 of the bending machine 6. The spring curvature of these underlay blanks 10 and 11 should be greater than that of the bendable blanks 1.

To bend the end edges 12 (Fig. 3) of the workpiece 1, an additional pressing element 13 is used, which has a length of 1 / R _extra curvature less than that required for part 1 / R by the amount of springing of the bent part, where R _add and R are the corresponding radii curvature. Such bending of the edges 12 of the long profiled blanks 1 can be carried out using the pressing element 13 with another bending device, for example, a press.

A comparison of the technical and economic indicators of the proposed method and device compared to flexible in a special stamp or when tight with stretching of two parts (sills l _zag = 700 mm and insert l _zag = 800 mm of the CT-100 tractor cab, mentioned above) is given in the table.

As follows from the table, the proposed method is not much inferior to other methods of bending in the longitudinally transverse direction of profiled parts in process performance, but in terms of stock, material and energy intensity of the processes significantly exceeds them, which corresponds to the tasks set in the invention.

The proposed method was tested at the shipbuilding company Almaz OJSC when bending pre-shaped workpieces of parts (sills l _zag = 700 mm and insert l _zag = 800 mm) on existing equipment (LGM 10/2000). Satisfactory results were obtained on the quality of bending, and the time for preparation of production was reduced by 20 times. In addition, when using the proposed technical solution, there is no need to manufacture complex metal-intensive special equipment for bending.

Claims (10)

1. A method of bending long profiled billets, in which the workpiece is moved in the longitudinal direction and perpendicular to the billet shelf defining the external bending radius, and parallel to its free walls a bending and opposed forces are applied relative to it, characterized in that at the site of the bending force is perpendicular to free walls of the workpiece exert constraining forces, reducing their corrugation. 2. The method according to claim 1, characterized in that in the place of action of the bending force in a plane perpendicular to the direction of the bending force, an additional corrective force is applied to reduce the unwanted side bending of the profile caused by its asymmetry. 3. The method according to claim 2, characterized in that the corrective force is applied in a place located after the second opposing force along the movement of the workpiece. 4. The method according to claim 1, characterized in that for guaranteed movement of the bent workpiece on its end edge, additionally apply static or impact forces. 5. The method according to claim 1, characterized in that the bending of the workpiece is carried out with a residual bend by the amount of its subsequent bending necessary to straighten the corrugations obtained by bending on thin free walls of the profile. 6. A device for bending long shaped workpieces containing pressure and support deforming elements made in the form of rollers having the cross-sectional shape of bent parts, characterized in that in the pressure roller, the grooves for the free walls of the workpiece are made with an extension from the axis of the roller. 7. The device according to claim 6, characterized in that the lateral working surfaces of the pressure roller are offset from the interacting surfaces of the support rollers directed in the opposite direction from the expected side bend. 8. The device according to claim 6, characterized in that it is equipped with a node that creates a corrective force, installed behind the second support roller along the workpiece. 9. The device according to claim 6, characterized in that between the push and support rollers an additional backing sheet element is installed, the amount of spring of which is greater than the spring of the bent workpiece. 10. The device according to claim 6, characterized in that for the bending of the end edges of the workpiece, an additional plug-in pressing element is used, having a cross-sectional shape of the bent workpiece and a curvature less than that required by the amount of workpiece springing.

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