RU2413586C1 - Method of hollow article rotary drawing - Google Patents

Abstract

FIELD: process engineering.

SUBSTANCE: invention relates to metal forming, particularly, to rotary drawing of hollow articles. Processed billet is clamped in the device comprising mandrel, biller clamp, hold down tool, flexible ring arranged aligned with mandrel to adjust ring cross section. Billet is revolved while spinning roll is cross-fed to allow roll face to come in contact with said flexible ring and strided to perform rotary drawing. Spinning roll axis is arranged at crossing angle α=2…5° with respect to billet axis, while mandrel direction of rotation is selected to allow spinning roll contingence and contact with flexible roll on the aide of angle (90°-α) between billet lengthwise axis and spinning roll face. Note here that the device is used flexible ring of which is made from bundles of metal wire frieze arranged lengthwise, jointed together by flexible mass to provide for interference relative to spinning roll face.

EFFECT: expanded process performances, higher quality and efficiency.

5 dwg

Description

The invention relates to the processing of metals by pressure, in particular to methods and devices for rotational drawing of cylindrical shells, hollow products and pressure processing.

A known method of rotational drawing, carried out using a mandrel containing a housing, an element for fastening the workpiece to the mandrel with screws, while an elastic element in the form of a ring, for example, made of polyurethane, is mounted on the clip coaxially with the mandrel, the ring being fixed to the clamp with screws, by which it is possible to adjust cross section of an elastic element [1].

The known method is implemented using a mandrel, which has in its design a rapidly wearing elastic ring that does not provide reliable contact of the pressure roller with the workpiece, while the design does not preclude the elastic ring from flowing under the pressure roller, and this entails metal grooves during the cutting of the pressure roller into the workpiece, which reduces the productivity and service life of the mandrel and the rapid wear of the working surface of the tool, while to obtain high quality necessary It requires the creation of large efforts of the elastic element on the roller, and this requires the use of rollers with a large profile radius, which negatively affects the weight and size parameters and is not always feasible.

The objective of the invention is to expand the technological capabilities of the rotary hood, improving the quality and productivity during processing, improving the conditions of deformation and metal flow, as well as reducing the likelihood of expansion, expansion of metal and the occurrence of scoring on the treated surface, ensuring reliable contact of the pressure roller with an elastic ring, eliminating the flow of the ring under the pressure roller and the exclusion of tearing of the metal in the process of cutting the pressure roller into the workpiece.

The problem is solved by the proposed method of rotational drawing of hollow products, including fixing the workpiece in the device containing the mandrel, the workpiece mounting element on the mandrel, the clamp mounted and fixed on the clamp coaxially with the mandrel, an elastic ring made with the possibility of adjusting the size of its cross section, message of the workpiece forced rotational movement, communication to the pressure roller of the transverse feed to ensure that its end touches the elastic ring device and enter into contact with it, and longitudinal feed for the implementation of rotational drawing, and the axis of the pressure roller is placed at a crossing angle α = 2 ... 5 ° relative to the axis of the workpiece, and the direction of rotation of the mandrel is chosen from the condition of ensuring contact and contact of the end face of the pressure roller with an elastic ring from the side of the angle (90 ° -α) between the longitudinal axis of the workpiece and the end of the pressure roller, while for securing the workpiece using a device whose elastic ring is made of tufts of pile of metal wire located longitudinally, connected to each other by an elastic mass and installed with the possibility of providing interference with respect to the end of the pressure roller.

The essence of the proposed method is illustrated by drawings.

Figure 1 shows a device that implements the proposed method, a longitudinal section, a pressure roller outside the processing zone; figure 2 is a top view along A in figure 1, on the left is a pressure roller in the final operating position; figure 3 is a longitudinal section of the device, the pressure roller at the time of implementation in the workpiece, left - pressure roller in the final operating position; figure 4 is a right view along B in figure 1; figure 5 is a cross-section along BB in figure 3, which shows the movement of the elastic ring and the tool in one direction, eliminating slipping and flowing of the ring under the pressure roller.

A device that implements the proposed method is designed for rotational drawing of hollow products 1 and contains a mandrel 2 and an element 3 for fixing the workpiece 1 on the mandrel. On the side of the front end of the mandrel 2, a clamp 4 is arranged coaxially with it, on which an elastic ring 8 is installed between the ring segments 6 and the ring 7 using screws 5.

The elastic ring 8 is made of tufts of pile 8 ′ of metal wire located longitudinally relative to the axis of the ring and connected to each other by an elastic mass of 8 ″, for example, SKU-7L polyurethane or rubber, which, when vulcanized, is firmly connected to the metal wire.

In the manufacture of the elastic ring 8, the density of the metal wire should include gaps that are filled with an elastic mass.

In order to prevent leakage of the elastic ring 8 under the pressure roller 9, its axis is rotated at a crossing angle α = 2 ... 5 ° relative to the axis of the workpiece 1. The rotation direction V _{ZAG of the} mandrel 2 is chosen so that the contact and the contact of the elastic ring 8 with the end face the pressure roller 9 would be from the side of the minimum angle (90 ° -α) between the longitudinal axis of the workpiece and the end of the roller (see figure 2, 5). According to figure 4, the rotation V _{ZAG of the} workpiece with the mandrel should be counterclockwise, and the roller clockwise.

Work on the proposed method is as follows.

The workpiece 1 is mounted on the mandrel 2, and using the element 3 and the clamp 4, the workpiece is _mounted on the mandrel with a force P _ZAZH . The spindle of the press machine (not shown), on which the mandrel 2 is mounted, is turned on. After this, the transverse feed S _{POP of the} caliper on which the pressure roller 9 is mounted. When approaching the workpiece 1, the pressure roller 9 touches the rear corner of the elastic ring 8, which rotates from the mandrel 2 through the clamp 4. With further transverse movement of the pressure roller 9, the area of contact with the ring 8 due to the elastic forces of the latter increases and rotation from the ring 8 is transmitted to the pressure roller 9, as a result, the circumferential orosti _CUG workpiece rotation V and V _{and h} davilnjami roller and its insertion slippage does not occur relative to the workpiece. The pile bundles located in the ring and installed with an interference fit i relative to the end of the roller will bend and improve adhesion to the roller, preventing it from slipping relative to the workpiece.

After cutting the pressure roller 9 to the required depth, the longitudinal feed S _{PR is} turned on and the product is rotationally drawn, the pressure roller 9 is rotated due to friction forces arising on the contact surface of the latter with the workpiece.

To ensure reliable contact of the pressure roller 9 with the elastic ring 8 and to avoid leakage of the ring under the pressure roller, the cross section of the elastic ring is adjusted by screws 5, the tightening torque of which is determined experimentally.

Rotational drawing of blanks of hollow products by the proposed method using a crossing pressure roller is performed, for example, on lathes with a longitudinal feed drive, the required spindle speed and sufficient rigidity of the technological system: machine, tool, tool, workpiece. In this case, the general requirements for the shape and geometry of the pressure rollers are the large width (10 ... 30 mm) of the abutment of the roller to the work surface, the minimum roughness Ra = 0.32 ... 0.080 μm of the hardened and polished working surface of the roller and the high rigidity of the technological system.

However, as the width K of the cylindrical girdle on the roller increases, the smoothing pressure decreases and the roughness increases; as a result, to achieve the required roughness, it is necessary to carry out processing with great efforts, which is not always possible due to insufficient rigidity of the technological system. The proposed cross rollers with a cylindrical belt require careful installation relative to the longitudinal axis of the workpiece.

The longitudinal feed during the rotation hood of the proposed method using a crossing roller is determined by the formula:

S _PR = (0.2 ... 0.5) K / cosα,

where K is the width of the cylindrical belt on the roller, mm;

α is the angle of intersection of the longitudinal axes of the workpiece and the roller, deg.

With proper installation, such rollers can work with longitudinal feeds within 3 ... 10 mm / rev, which makes the process of rotational drawing very productive.

As a pile, a steel spring wire is used, for example, with a diameter of 0.5 ... 1.0 mm from steel 65G, while the tightness is set i = 1.2 ... 1.5 mm.

The force of pressing the elastic needle ring to the end of the roller is 200 ... 300 N and depends on the depth of penetration of the roller into the workpiece.

The choice of the appropriate pressure depends on the physicomechanical properties of the material of the wire pile, on the rigidity and density of the latter, as well as on the interference fit i.

Using the proposed method allows to expand the technological capabilities of rotary hoods, to improve the quality and productivity of processing, to improve the conditions of deformation and flow of metal, while reducing the likelihood of expansion, expansion of metal and the occurrence of scoring on the treated surface, to ensure reliable contact of the pressure roller with an elastic ring, and to prevent the ring from flowing under the pressure roller and tearing of the metal during the process of cutting the pressure roller into the workpiece, and also predict the roughness vatost and surface quality.

Information sources

1. Copyright certificate SU No. 1593737, MKI B21D 22/16. Nazarov V.I., Zubarev V.V., Sorokin Yu.G., Khmelev S.V., Gladkikh A.A., Malkov V.P. Mandrel for rotational extraction of hollow products. Application No. 4466461 / 25-27. 07/26/88; 09/23/90. Bull. Number 35.

Claims (1)

A method of rotational drawing of hollow articles, including fixing the workpiece in a device containing a mandrel, a workpiece mounting element on a mandrel, a clamp, an elastic ring mounted and fixed on a clamp coaxially with the mandrel, configured to control its cross-sectional size, communicating the workpiece with forced rotational movement, communication to the pressure roller of the transverse feed to ensure that its end touches the elastic ring of the device and comes into contact with it and the longitudinal th feed for the implementation of rotational drawing, characterized in that the axis of the pressure roller is positioned at a crossing angle α = 2 ... 5 ° relative to the axis of the workpiece, and the direction of rotation of the mandrel is selected from the condition of touching and contacting the end of the pressure roller with an elastic ring from the angle (90 ° -α) between the longitudinal axis of the workpiece and the end face of the pressure roller, while to fix the workpiece using a device whose elastic ring is made of tufts of pile of metal wire arranged longitudinally, connected nennyh with each other and an elastic mass mounted for providing tightness with respect to the end face davilnjami roller.

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