RU2409442C1 - Unit of spinning rolls for rotary burnishing of billets - Google Patents

Abstract

FIELD: process engineering.

SUBSTANCE: invention relates to metal forming, in particular to rotary burnishing of billets. Two spinning rollers are fitted on central shaft and separated by spacing ring. One of said rollers has starting section with needle peripheral surface formed by metal wire frieze bunches with certain front angle and is rigidly fitted on central shaft to be driven by second roller via planetary gear consisting of external gear wheel with inner toothed rim running free in bearings on central shaft and differential pinion in mesh with said external gear wheel fitted on free revolving axle running in bearings on mandrel. There is central wheel rigidly fitted in aforesaid central shaft to run in bearings on mandrel. Note here that rollers may revolve in opposite directions, while second roller has squeezing section arranged at certain angle, calibrating section and burnishing section representing a polymer ring fitted in place with the help of washer and screw.

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.

Known designs of pressure rollers, the nature of the processing process which depends on the radius of rounding and the width of the girdle [1]. 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 the 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 has a lead-in section with a needle-shaped peripheral surface from tufts of bristles made of metal wire with a front angle φ ₁ = 20 ... 30 °, is rigidly mounted on the central shaft with the possibility of forced rotation from the second roller by means of a planetary gear transmission, consisting of a second mu roller of the female wheel with an internal gear rim, freely mounted on bearings on the central shaft, a satellite engaged with the female wheel, mounted on a freely rotating axis mounted on bearings on the mandrel, and a central wheel rigidly mounted on the aforementioned central shaft having the possibility of free rotation on bearings on the mandrel, wherein the rollers are rotatable in the opposite direction and the second roller has a crimp portion at an angle φ ₂ = 30 ... 40 °, caliber conductive band portion and the iron in the form of a ring of a polymeric material mounted using screws and washers.

The essence of the design of the proposed block and its operation are illustrated by drawings.

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

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

The performance of rotary smoothing, as well as the quality of the surfaces of the 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 central shaft 3, while the rollers are separated by a spacer ring 4.

The block has a complex profile and consists of three sections - inlet 5, crimp 6, ironing 7 and calibrating girdle 8.

The approaching section 5 is made on one roller 1, fixed firmly on the central shaft 3 with the help of a key 9, fixed on it with a nut 10 and has a forced rotation V _P from the second roller 2 due to the planetary gear 2-11-12. The peripheral surface of the roller 1 is made of needle wire from tufts of pile from a metal wire with a rake angle φ ₁ = 20 ... 30 °.

Planetary gear transmission 2-11-12 consists of a female gear with an internal gear rim belonging to the second roller 2 and freely mounted on bearings 13 on the central shaft 3. The planet gear includes a gear - satellite 11, which is meshed with the female gear 2. The satellite 11 is mounted on a freely rotating axis 14 mounted on bearings 15, which are mounted in the mandrel 16. The planetary gear also includes a central wheel 12, which, with the help of a key 17, is rigidly mounted on a central shaft Lu 3. The Central wheel 12 is in constant engagement with the satellite 11. The Central shaft 3 freely rotates on bearings 18 mounted in the mandrel 16.

Thus, this planetary gear 2-11-12 transmits rotational movements V _P and V _C , respectively, to the rollers 1 and 2 in opposite directions (see figure 4).

On the peripheral surface of the second roller 2, a crimping section 6 is made at an angle φ ₂ = 30 ... 40 °, a calibrating girdle 8 of width K and a smoothing section 7 in the form of a ring of polymer material mounted using a washer 19 and screws 20 at the end of the roller 2.

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 ₁ = 20 ... 30 °. The bundles of wire pile on the hub of the roller 1 are fixed by known methods and create favorable conditions for shaping, eliminating slippage and reducing the likelihood of sagging before crimping and ironing. The rollers 1 and 2 rotate independently of each other in opposite directions, which makes it possible to improve the flow conditions of the metal and reduce the likelihood of burrs on the surface being machined.

The oncoming movement of the lead-in 5 and crimp 6 sections helps to reduce stresses in the deformation zone and stabilizes the pressure process of rolling in and deformation. Choosing the ratio of the speeds of the rollers, establish the optimal value, as a result of which create favorable conditions for shaping.

For effective processing before work, the tool block is fed in the transverse direction to create an interference fit within 0.2 ... 0.7 mm.

The rake angle φ ₂ is the angle of entry of the metal into the deformation zone, and the smaller it is, the lower the stress in the deformation zone, the more stable the pressure process of rotational drawing.

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 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 smoothing section 7 is a calibrating girdle 8, which prevents the appearance of sagging in front of the roller 2, which is very likely when processing thick-walled workpieces. Calibrating girdle, as a rule, take a width of K = 1.5 ... 3 mm. 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 bands K, the deformation forces significantly increase and the quality of the processed surface decreases.

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, determined by the formula 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 belt K with the working faces take within 1 ... 3 mm.

A pressing element in the form of a ring of polymer material, for example, polyurethane grades SKU 7-100 or SKU-IFL, is installed on the ironing section 7. The ring is fixed from the end of the second roller 2 with the washer 19 and screws 20. This pressure element operates as follows. Before processing, the pressure element is set to the specified stiffness, depending on the material being processed, by axial movement of the washer with 19 screws 20. The use of a polymer ring on the ironing section improves the quality of the product due to the possibility of controlling the stiffness of the polymer pressure material depending on the characteristics of the material being processed [2].

The proposed block of pressure rollers is used on powerful pressing machines operating by the method of reverse rotation drawing of thick-walled workpieces. 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 (see figure 5); I - the smallest radius of inertia of the cross section of 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 = 0.2 ... 0.7 mm.

Modes of operation of the needle part: the peripheral speed V _{C is} taken equal to the speed of the workpiece. As a result, the roughness by one class is improved, the pressure of the block against the workpiece surface is 200 ... 300 N per 10 mm of the width of the working surface of the needle part.

For processing by the proposed unit, it is necessary to observe the condition: p / σ _in = 1.5 ... 2.0, where p is the pressure during deformation, 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, for the purpose of restoration it is desirable that the tufts of the pile radially extend and are governed by grinding on the outer diameter after each dressing.

The surface microrelief formed as a result of smoothing is determined by the following main factors: kinematics of the process (the direction of mutual movement of the tool and the workpiece; initial roughness; shape and size of the initial part and the smoothing tool; depth of penetration of the tool into the surface to be treated; feed rate; plastic flow of metal, which causes the appearance of secondary roughness; roughness of the working part of the tool; value of elastic recovery surface after ironing; vibration of the technological system machine-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 unit allows expanding the technological capabilities of deformation and drawing due to the combination of an acrylic resin with a polyurethane pressure element, improving the quality and productivity of processing, improving the conditions of deformation and metal 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 of the processed surface.

Information sources

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

2. Copyright certificate of the USSR, No. 1558534, MKI B21D 22/16.

Claims (1)

Block of pressure rollers for rotational smoothing of workpieces, consisting of two rollers seated between themselves by a spacer ring, one of which has rollers, one of which has a lead-in section with a needle-shaped peripheral surface from tufts of pile of metal wire with a front angle φ ₁ = 20 ° ... 30 °, rigidly mounted on the Central shaft with the possibility of forced rotation from the second roller by means of a planetary gear transmission, consisting of a female wheel belonging to the second roller with an internal gear in a free wheel mounted on bearings on a central shaft, a satellite engaged with a female wheel mounted on a freely rotating axis mounted on bearings on a mandrel, and a central wheel rigidly mounted on a central shaft having free rotation on bearings on a mandrel while the rollers have the ability to rotate in the opposite direction, and the second roller has a crimp section at an angle φ ₂ = 30 ° ... 40 °, a calibrating girdle and a smoothing section in the form of a ring of n polymer material installed with washers and screws.

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