SU1655629A1 - Punch for expanding hollow shells - Google Patents

Description

The invention relates to the processing of metals by pressure. The purpose of the invention is to increase the marginal degree of distribution and improve the quality of the resulting product by reducing the uneven distribution of deformations on the surface of the shell and eliminate the cut. The uniform distribution of strain is ensured by the fact that in the initial stage

Forming changes are applied to uniform distribution of the shell sections, which constitute 70 ... 80% of the volume of the workpiece, and eliminate the stress concentration on the shell from the tool. This is ensured by the fact that the edge sections of adjacent sections (C) 2 are made in the form of combs entering each other, due to which during the distribution process there are no parts of the connector between C 2 and the faceting is eliminated. The radius of the working surface of the middle part C 2 exceeds the radius of the edge sections of the working surface of the dies by 10 ... 20%. as a result, at the initial moment of shaping, the billet is deformed by the edge sections C 2 and the stress concentration is eliminated. At the final moment of distribution, the tool forms a closed loop, identical to the contour of the required part, since only the middle parts of C 2 are in contact with the workpiece. 3 Il.

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The invention relates to the processing of metals by pressure, and is intended, in particular, to obtain hollow cylindrical shells by dispensing on a single-action press.

The purpose of the invention is to increase the marginal degree of distribution by reducing the non-uniformity of deformation and the action of contact friction forces and improving the quality of the resulting product by eliminating the cut.

FIG. 1 shows the punch, in the initial state; in fig. 2 - the same. without a wedge: in FIG. 3 - view of one of the sections.

The punch for dispensing hollow shells contains a central wedge 1, made in the form of a truncated pyramid, which is attached to the press slide (not shown). Section 2, surrounding the wedge, mounted on the bottom plate 3 with the possibility of radial movement on it.

Edge sections of sections 2 are made in the form of combs, i.e. with through slots 4 parallel to the surface of the plate. The radius P of the surface of the edge parts of sections 2 is equal to the radius of the workpiece g _About b. The grooves 4, made on one of the edge sections of the sections 2, are shifted by half a step relative to the grooves 4, made on the other edge section of the sections 2, which allows the edge sections of the adjacent sections to enter each other, thereby forming the outer contour. The middle part 5 of sections 2, which is in contact with the blank 6 in the process of distribution, is made with a radius of yy equal to the radius P of the finished product 7.

Punch works as follows.

The workpiece 6 is put on the section 2 of the unclamping tool, and it contacts only with the edge sections of the sections 2. which are made along the radius g. The edge sections of the adjacent sections 2 in the initial state enter into each other.

When the press ram moves downward, the wedge 1, falling, begins to push sections 2 in the radial direction, which begin to distribute workpiece 6 with their edge sections. Thus, the contact surface of section 2 with workpiece 6 at this moment does not exceed 20% of the last surface, then the main volume billet 6 is molded uniformly without the formation of sharp sinkers in height, and uneven thickness. In the process of distribution of the edge sections of sections 2, made in the form of combs, out of each other, increasing the diameter of the outer contour of the punch.

With the further progress of the press ram down, the edge sections of the sections 2 come out of contact with the workpiece 6, and to replace them in

the contact is entered by the middle parts of 5 sections 2, which are made along the radius gg. At the moment when the wedge 1 drops to the lowest position, the edge sections of sections 2 will come out of contact with the shell, and only the middle parts 5 of sections 2 will contact, and the contact surface will be without connectors, since the edge sections of adjacent sections 2 will not come out of each friend that will prevent the cut. At this point, the outer contour of the punch will have dimensions equal to the required dimensions of the finished part 7.

When the press ram moves upward, the wedge 1 will release sections 2, which will return to their original position using, for example, a spring (not shown), thereby freeing the finished part 7.

If we consider that the average circumferential deformation of the shell is determined by the formula

e = 1gf = 1n ^ -, (1)

“Oh go

where Ρι, Ro and B, Go are the current and initial perimeters and radii of the inner side surface of the shell, usually within (0.1-0.2), and the difference between the radii of the working surfaces of the edge sections of the dies and the middle part of the section is (10 ~ 20 )%, it can be concluded that the edge areas of the dies are made with a radius equal to the inner radius of the workpiece, and the middle part of the section has a radius equal to the radius of the finished product.

From FIG. 2 you can find the length H of overlapping sections of the working surfaces of the sections (And determined by the length of the arc AB). The considered section is shifted along its vertical axis of symmetry оо ¹ , i.e. Point A on the working surface of the section shifts to the point Αι during the working stroke. moreover, the length of the segment ΑΑι is equal to the length of the working stroke and section, the straight line ΑΑι is parallel to the straight line OO '., i.e. <ΑΑιΟ = a

By symmetry, the straight lines AB and Αι are perpendicular with ΑΒι = ΒιΒ. At the same time in a right triangle ΑΑιΑΑι.

ΑΒι = ΑΑι’z) l a = a.z! P a, i.e.

AB = 2AB1 = 2a δΙηα.

Let B 'is the projection of point B on the arc AO'E, then the length of the arc AB' is approximately equal to the length of the segment AB:

Р7 \ В = 2а δΙη a (2)

where 2a is the angle of the section solution.

Thus, the minimum length of the working surface of each comb is equal to

NK this length should also add be5

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The 1g figure is equal to the length of the edge portion of the comb made with the radius of the working surface p. The magnitude 12 is about 10% of the total length of the working surface of an individual section (since the total length of the sections with radius n is about 20% of the perimeter of the inner side surface of the workpiece) the number of such sections is 2Ν, where N is the number of tool sections).

The total length ί of the working surface of a separate section is 1_ = 2Ра, respectively, the length I in the circumferential direction of the working surface of each comb is equal to) = 1гН2 · where 1г = 0.11. Then, taking into account the expression (2), the ratio 1 / 1_ can be found:

I _ C +1 ₂ _ Η +0.1 I. Η,

Ι_ 1_ Ι_ ί ⁺

+ 0.1 = - ^ ~ - · | +0.1 (3)

Given that P-a = g _o , expression (1) can be written as

from where

I = 1 - e '(5)

Since the value of ε is small (ε <0,2), then from (5) it follows: a / B - ε, substituting it into (3), get

Ε- ^ · ε + 0.1 (6)

As is known, the value 5ΐη «/ β <1, therefore, taking ZI a / a = 1 and ε 0,2. we get 1 / 1_0,3, and for constructive reasons we assign

~ = 0.3-0.4, (7)

The implementation in the initial stage of deformation by uniform distribution of shell sections that are not in contact with the tool and constituting up to 80% of the volume of the workpiece, as well as reducing the magnitude of the friction forces arising on the surface of the contact of the workpiece with the tool, allows increasing the limiting degree of deformation and improving the quality of the resulting product by reducing the non-uniformity of deformation over the surface of the shell.

Performing marginal parts <in sections in the form of combs entering each other, with a radius equal to the radius of the workpiece, in the middle part of the sections with a radius equal to the radius of the finished product, can improve the quality of the resulting part by eliminating the cut and spreading the size of the finished part across its diameter.

Claims (1)

Claim A punch for dispensing hollow shells containing a central wedge and sections radially sliding around it on a slab, differing from the fact that, in order to improve the quality of the product obtained by eliminating the cut and expanding technological capabilities by increasing the marginal degree of distribution while reducing unevenness deformations, edge sections of sections are made in the form of combs entering into each other, each of which is made 30–40% of the total working surface length o individual section, while the working surface of the middle part of each section is made with a radius of 10-20% higher than the radius of the working surface of the edge sections of the combs on a length of 0.1 of the total length of the working surface of the section 1655629