RU2409441C1 - Unit of spinning rolls for rotary burnishing of billets - Google Patents

Abstract

FIELD: process engineering.

SUBSTANCE: invention relates to metal forming, particularly to devices intended for rotary burnishing and spinning. Unit of spinning rolls consists of two rolls fitted on one axle and separated by spacing ring. Said rolls feature profile consisting of three sections, i.e. starting, squeezing, burnishing and gauging cylinder. Note here that said starting section is made on one roll rigidly fitted on the axle with forced rotation. Said roll needle surface is made from metal wire frieze bunches with preset front angle. Second roll running free in axle bearings has spinning section arranged at preset angle and burnishing section with preset angle separated by gauging cylinder that represents a sine tape.

EFFECT: expanded process performances, higher quality and efficiency.

5 dwg

Description

The invention relates to the processing of metals by pressure, in particular to devices for rotational smoothing and pressure processing.

A known design of a pressure roller, the cross-section of which in a plane passing through the axis of rotation parallel to the forming mandrel, is limited to a flat section with a transition section with a radius of 0.5 ... 0.8 diameter of the pressure roller, a working section outlined along the radius with the peripheral part made in the form of a cylindrical surface with a generatrix parallel to the axis of the roller and smoothly conjugated with the working surface in cross section of the largest diameter of the pressure roller [1].

However, this design of the roller with the peripheral cylindrical part has a significant drawback: the selected angle is in the range of 6 ... 12 °, non-observance of which leads to a reduction in productivity and tool life due to the rapid wear of the working surface, limited by the radius, and to create high quality it is necessary to create large working efforts, and this requires the use of rollers with a large profile radius, which negatively affects the overall dimensions and is not always feasible.

A known roller for pressing processing, the cross section of which in the plane passing through the axis of rotation, is limited by the conjugate arcs of circles of different radii, and the ratio of the radii of the circles is selected within 13-15 [2].

A disadvantage of the known roller is its small contact surface interacting with the part, which does not provide high roughness of the finish of the processed surface, which results in low surface quality and requires a large number of technological transitions, which sharply reduces productivity. Another disadvantage of the pressure roller is the difficulty of restoring the shape of the roller as a result of wear, since for this it is necessary to grind all external surfaces with a change in grinding radii to maintain a mate of radii. At the same time, adjustments are required in the technological modes.

A pressure roller with a double-sided cone is known, for which the angles φ and φ ₁ are selected in the range from 30 to 35 °, and the mating radius of the conical surfaces is from 6 to 8 sheet thicknesses, i.e. from 6 to 32 mm [3].

Such a pressure roller works well when rotationally smoothing shells with a convex-concave surface, but it does not achieve surface roughness, eliminating the need for surface refinement by grinding.

Known designs of pressure rollers, the nature of the processing process which depends on the radius of rounding and the width of the girdle [4]. However, the disadvantage of the known pressure rollers is the difficulty of restoring the shape as a result of wear, since for this it is necessary to grind all external surfaces with a change in the grinding radii to maintain the mating radius. At the same time, adjustments are required in the technological modes. In addition, the disadvantage is their small contact surface interacting with the part, which does not provide a high roughness of the finish of the processed surface, which results in low surface quality and requires a large number of technological transitions, which sharply reduces productivity.

The objective of the invention is the expansion of technological capabilities, improving the quality and productivity during processing, improving the conditions of deformation and flow of metal, as well as reducing the likelihood of expansion, expansion of metal and the occurrence of scoring on the treated surface, reducing the likelihood of sagging in front of the tool when processing thin-walled blanks from durable materials.

The problem is solved using the proposed block of pressure rollers for rotational smoothing of billets, consisting of two rollers seated on each axis by a spacer ring, one of which is rigidly mounted on the axis with the possibility of forced rotation, made with a lead-in section with a front angle φ = 20 ° ... 30 °, and the needle peripheral surface of the pile of bundles of metal wires, the second roller is seated freely on bearings on the axis and is configured to crimp portion at an angle φ ₂ = 30 ° ... 40 °, etc. glazhivayuschim portion with a clearance angle φ ₁ = 35 ° ... 45 °, separated by a caliber belt formed as a sinusoidal strip.

The essence of the design of the proposed unit and its operation is illustrated by drawings.

Figure 1 shows a block of pressure rollers for rotational smoothing of both thin-walled and thick-walled parts, a partial longitudinal section; figure 2 is a view along B on the front end in figure 1; figure 3 - element In figure 1; figure 4 is a section GG in figure 3; figure 5 is a section DD in figure 3.

The proposed tool block consists of two rollers 1 and 2, mounted on one axis, and serves to improve the conditions of deformation of the workpieces. The workpiece, for example, worn on a mandrel (not shown), is informed of a rotational movement, and the needle roller 1 is rotationally driven V _AND , while the pressure roller 2 receives rotation from the workpiece due to friction forces. In addition, a longitudinal S _PR feed is reported to the block.

The performance of rotary smoothing and the quality of the surfaces of parts largely depend on the shape and geometric parameters of the pressure rollers.

The proposed tool block consists of two rollers 1 and 2, mounted on one axis 3. The rollers are separated by a distance ring 4. The block has a complex profile and consists of three sections - inlet 5, crimp 6, ironing 7 - and calibrating belt 8.

The approach section 5 is made on one roller 1, mounted on the axis 3 rigidly with the help of a key 9, fixed on the axis with a nut 10 and has a forced rotation with a speed of V _And from an individual engine (not shown). The peripheral surface of the lead-in section 5 is made of needle wire from tufts of pile made of metal wire with a rake angle φ = 20 ° ... 30 °. The bundles of wire pile in section 5 are fixed by known methods and create favorable conditions for shaping by introducing needles into the surface to be machined and forcibly lead with a rotation speed V _{AND the} workpiece, eliminating slippage and reducing the likelihood of sagging before crimping and ironing. For the introduction of needles into the treated surface before processing, the tool block is fed in the transverse direction to create an interference fit within 0.5 ... 1.0 mm.

The second roller 2 is freely mounted on the roller bearings 11 on the axis 3, secured by a cover 12 and has a working surface consisting of a crimp section 6 made with a rake angle φ ₂ = 30 ° ... 40 ° to the axis of rotation, and a smoothing section 7 with a rear angle φ ₁ = 35 ° ... 45 °. Roller 2 rotates independently on bearings, which makes it possible to reduce the difference in speeds at the points of contact of the tool with the workpiece, improve the flow conditions of the metal and reduce the likelihood of galling on the work surface. The rake angle φ ₂ is the angle of entry of the metal into the deformation zone and the smaller it is, the less stress in the deformation zone, the more stable the process of rotational smoothing.

The proposed block allows you to deform, for example, tubular workpieces to various lengths in any area with preliminary introduction into the metal. The crimping part 6, which is the inlet, of the roller 2 has an angle φ ₂ = 30 ° ... 40 °, which helps to reduce the influx, and also affects the stability of the process and the distribution of forces between the longitudinal and transverse components. A smaller angle φ _{2 is} taken when machining aluminum, copper and low carbon steel, a larger angle φ ₂ is used when machining high-strength steel and titanium, since the deformation forces decrease with an increase in the angle φ ₂ .

When φ ₂ <20 °, the possibility of sagging in front of the roller increases, which is undesirable.

Between the crimp section 6, made at an angle φ ₂ to the axis of rotation, and the ironing section 7 with a rear angle φ ₁ is a calibrating girdle 8, made in the form of a sinusoidal tape. The belt 8 prevents the appearance of sagging in front of the roller 2, which is very likely when processing thick-walled workpieces. The calibrating girdle, as a rule, is taken with a width of k = 1.5 ... 3 mm, where k is the width of the girdle of known designs of pressure rollers. Since the longitudinal feed, determined by the formula S _PR = (0.2 ... 0.3) k, depends on the width of the belt, they tend to increase the width of the belt, however, with wider belts k, the deformation forces increase significantly and the quality of the machined surface decreases.

In order to increase productivity and improve the quality of the treated surface during deformation in the proposed block design, we take the form of a calibrating girdle 8, made in the form of a sinusoidal tape, characterized by the magnitudes of the amplitude K and step A (see figure 3-5). This design allows for the same width of the calibrating girdle (k = K ₁ ) and without increasing the deformation force, to increase the longitudinal feed S _{PR by} n = (K / K ₁ ) times and to improve the quality of the processed surface.

The radius of the working edge R, which is assumed to be approximately equal to the thickness of the deformable workpiece, has the same effect. When applying S _PR = (0.2 ... 0.3) K, the roughness of the treated surface is achieved from Ra = 40 μm to Ra = 1.25 μm. The radiuses of conjugation of the sinusoidal girdle K with the working faces take within 1 ... 3 mm. In the manufacture of interfaces between the calibrating girdle 8 and surfaces 6 and 7, the front φ ₂ and rear φ ₁ angles slightly decrease and take values, respectively, φ ₂ ′ and φ ₁ ′, however, these changes do not significantly affect the operation of the unit (see Fig. .4, 5).

The proposed block of pressure rollers is used on powerful pressing machines operating by the method of reverse rotational smoothing of thick-walled workpieces [3, 4]. The diameters of the rollers are taken from design considerations. With an increase in the diameter of the roller, deforming forces and bending moments acting on the support of the machine increase. It is necessary to strive to use rollers of the same diameter for each machine. This is especially important for CNC machines.

The deformation of the proposed block is carried out with minimal rigidity of the inlet needle part. As a pile, a steel spring wire is used, for example, with a diameter of 0.5 ... 1.0 mm from steel 65G. Use the needle part with the ratio h / I, where h is the length of the pile over the hub of the roller; I - the smallest radius of inertia of the cross section of the wire elements within 50 ... 100, and the coefficient K _{p the} density of the wire pile in the range of 0.6 ... 0.8; the tightness was - i = 0.7 ... 1.5 mm.

Modes of operation of the needle part: peripheral speed V _And taken equal to the speed of the workpiece. As a result, the roughness by one class is improved, the force of pressing the acrylic on the workpiece surface is 200 ... 300 N per 10 mm of the width of the working surface of the needle part.

For processing the proposed needle block, it is necessary to comply with the condition: p / σ _in = 1.5 ... 2.0, where p is the pressure during needle formation, MPa; σ _in - the tensile strength of the material of the workpiece, MPa.

The choice of the appropriate pressure p 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.

Since the needle roller wears out on the outer diameter, it is desirable for the purpose of restoration that the tufts of the pile radially extend and grind on the outer diameter after each dressing.

The surface microrelief formed as a result of smoothing is determined by the following main factors: the kinematics of the process (the direction of mutual movement of the tool and the workpiece; initial roughness); the shape and size of the initial part and the smoothing tool; the depth of penetration of the tool into the work surface; feed rate; plastic flow of metal, causing the appearance of secondary roughness; roughness of the working part of the tool; the value of the elastic recovery of the surface after smoothing; vibrations of the technological system machine-tool-tool-tool-workpiece, as well as the magnitude of the tightness of the needle tool.

When ironing parts made of steel, brass and aluminum alloys, good results are obtained by using industrial oil I-20A or sulfofresol as a lubricant.

Using the proposed block allows expanding the technological capabilities of rotational smoothing thanks to a combination with a needle block and a sinusoidal calibrating girdle, increasing the quality and productivity of processing, improving the conditions of metal deformation and flow, reducing the likelihood of expansion, expansion of metal and the occurrence of scoring on the treated surface, as well as predicting roughness and quality the processed surface.

Information sources

1. USSR Copyright Certificate, No. 1620182, MKI B21D 22/14.

2. Copyright certificate of the USSR, No. 845980, MKI 3 B21D 22/18.

3. The grave NI Rotational extraction of shell parts on machines. M .: Engineering, 1983, p. 144-145, Fig. 9.2.

4. Mogilny N.I. Rotational extraction of shell parts on machines. M .: Engineering, 1983, p. 147, Fig. 9.6.

Claims (1)

The block of pressure rollers for rotational smoothing of workpieces, consisting of two rollers seated between each other by a spacer ring, one of which is rigidly mounted on the axis with the possibility of forced rotation, is made with a lead-in section with a front angle φ = 20 ° ... 30 ° and a needle peripheral surface of the pile of bundles of metal wires, the second roller is seated freely on bearings on the axis and is configured to crimp portion at an angle φ ₂ = 30 ° ... 40 ° and ironed portion to the rear angle φ ₁ = 35 ° ... 45 °, divided 's belt between a caliber formed in the form of a sinusoidal strip.

Images