SU1655595A1 - Method straightening long articles - Google Patents

Abstract

The invention relates to the technology of straightening products with flat bending. The purpose of the invention is to improve the quality and productivity of edits. The product is mounted on the end supports and the intermediate support is supplied, which, during the editing process, is periodically moved from one end support to the other by an editing step, which is calculated from certain ratios of m. The dressing is performed by bending the product in the area between the end and intermediate supports, having the point of application of the bending force at the distance of the dressing step from the intermediate bearing. The area to be corrected each time includes the already straightened area, which allows to reduce the deviation from the straightness along the entire length of the product 1 silt., 2 tabl

Description

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The invention relates to the processing of metals by pressure, in particular to the technology of straightening with flat bending, and can be used in metallurgy and mechanical engineering for straightening lengthy workpieces and products.

The purpose of the invention is to improve the quality and performance of edits.

The drawing shows the implementation of the proposed method.

The area to be corrected each time includes the already straightened area, which allows to reduce the deviation from the straightness along the entire length of the product.

The product 1 is mounted on the fixed end supports 2 and intermediate support 3 is supplied, which is periodically moved during the dressing process to step a. The straightened section located between one of the end supports 2 (in the left drawing) and intermediate support 3, which is bent by a force Q applied at a distance of step a from intermediate support 3.

Step and edits are determined from the ratios

1 to

l

f

+,

8 n2 2 where I is the length of the straightened product,

n is the number of edit steps:

K - the largest absolute value of the curvature of the product,

A - tolerance on the accuracy of product editing in each section, determined by the features of the technological process and equipment;

d - permissible deviation of the product axis from the linearity along its entire length.

The quantitative ratios for the proposed method are selected as follows.

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Editing of each section of products is carried out in real conditions with finite accuracy, characterized by the maximum possible error (5j, j1, 2n-1, due to the error in the cross-sectional shape of the product; measurement error of linearity; overrun of the device for creating an effort to correct, for example, striking power cylinder. The total deviation from the straightness in the lth section, due to errors 6j, is equal to

N 1 s

Yi l 2 i - l 1.2 ..., p-1, J

the total deviation in the cross section located between the i-1st and i-th sections is equal to

Yi1, y1 au

 2 2

If all 5j are equally distributed random variables, then the maximum. Y value is approximately equal.

The component of the correction error, due to the uncorrected irregularity of the product axis at a length equal to the straightening step, does not exceed the value of Ka / 8 or KI2 / 8n2. Here it is assumed that on sufficiently short segments of the product the deviation of its axis from the linearity is approximated square parabola, which is sufficiently confirmed experimentally.

The total error of editing should not exceed the permissible value. It follows that the edit step and the number of technological transitions must be chosen from the ratios;

1 to.

12 .

 8nz 2

With the step size, more calculated, the error of editing may exceed the permissible, and the required quality of editing will not be achieved. If the edit step is less than the calculated one, then the edit will require a larger number of transitions, which will lead to a decrease in the performance of the process.

Editing is carried out as follows.

The product is installed with end parts on two end supports, the deviation of the axis of the product from straightness in the straightening plane is determined. From these values, the curvature of the axis is calculated. Then, using the above ratios, the edit step and the number of transitions are calculated. In the case of serial production of products of the same type using the established technology, curvature measurements and calculations can be performed not for each product, but for one rather representative sample, but

then you can use the smallest received value of the edit step.

After determining the straightening step and the number of technological transitions, an intermediate support is established at a distance of two straightening steps from one of the end supports. If the straightness requirements of the product are asymmetrical, i.e. for one half of the product, greater linearity is desirable than for the second, then intermediate

The support is installed in that half of the product, the straightness requirements of which are lower. Between the intermediate support and the end support nearest to it, a straightening force is applied, which creates an elastoplastic bending of the product until the smallest possible under real conditions, axis deviation in the section of application of the load from the linearity. Deviation from linearity

it is fixed by a measuring device, which is installed in the section for the application of a straightening force. Then the intermediate support is shifted towards the second end support by an amount equal to the straightening step. Same

displaces the device that generates the force of the straightening and the measuring device, after which, by applying the force of the straightening, an elastoplastic bend ensures the minimum possible deviation from

the linearity of the axis of the product in the cross section of the applied load. Further, all technological transitions are repeated: the displacement of the intermediate support; displacing the force-adjusting device and the measuring device; editing the next section of the product, including already processed until the intermediate support does not come to the end. After that, the product is edited one last time and removed from the supports.

Example. The preparation is subjected to editing, the non linearity of the axis of which is characterized by the data in Table. 1. Editing accuracy in each technological transition

not more than 0.3 mm, the required straightness of the axis of the workpiece is not less than 1.0 mm.

In tab. Table 1 also shows the curvature values of the product axis (the reciprocal of the radius of curvature), calculated by a finite difference method. The greatest value of the curvature of the axis of the workpiece 6.5. From the ratios of the proposed method, the necessary step of editing is determined;

6.5

ID 3 m-1

. (6m) 2

ViT T

8p

 1.0mm

from which it follows that n 7: a 0.9 m.

In tab. Figure 2 shows the calculated values of the maximum possible editing error in the implementation of the proposed method with a different editing step.

From the data it follows that the proposed method meets the requirements for the quality of editing at a 0.9 m, which corresponds to the calculated step size.

The proposed method provides straightening of long products with increased requirements to the straightness of the product axis along the entire length with high productivity.

Claims (1)

Invention Formula The method of straightening lengthy products, in which the product is installed on the end supports and the intermediate supports moved during the editing process, its curvature is measured, the dressing step is determined and the product is periodically bent by applying force between the supports. five directed in the direction opposite to its initial curvature, and lying in a plane, passing through the longitudinal axis of the product, characterized in that, in order to increase the productivity and quality of dressing, the section between one of the end and intermediate supports is periodically bent, two steps of straightening from the specified end support and periodically moving it one step in the direction of the second end support, and the bending force is applied at a distance from the intermediate support equal to the step , The step changes are determined from the relations a -; K I2 +, 8n where a is the editing step; I is the length of the straightened product; n is the number of edit steps; K - the largest absolute value of the curvature of the product; A is the tolerance on the accuracy of product editing in each section, determined by the features of the technological process and equipment;  d - permissible deviation of the product axis from the linearity along its entire length. Table 1 table 2