RU2275290C1 - Embracing ring for strengthening rolling - Google Patents

Abstract

FIELD: metal working.

SUBSTANCE: embracing ring comprises deforming member for surface plastic deformation made of a ring with tree-step inner working surface made of the front smoothing cone, strengthening collar, and back cone. The ring is mounted in the bearing for permitting free rotation. The inner diameter of the ring is determined from the formulae proposed.

EFFECT: expanded functional capabilities.

10 cl, 1 ex

Description

The invention relates to the processing of metals by pressure, in particular to tools and accessories for processing by surface plastic deformation (PPD) of bodies of revolution such as shafts.

A device is known in which the deforming element for the surface plastic deformation of rotational bodies of the shaft type is a ring covering a workpiece with a three-stage internal working surface made in the form of a front smoothing cone, a reinforcing girdle and a rear cone arranged in series in the longitudinal feed direction [1].

A disadvantage of the known device is the low quality of the surface being treated, caused by large friction between the tool and the workpiece, which also negatively affects the wear of the deforming element.

Known three-roller device for rolling in non-rigid shafts, consisting of a holder with rollers, pivotally connected to the housing, which is mounted on the support of the machine [2]. The device is equipped with reinforcing deforming elements in the form of toroidal rollers, for example, according to GOST 16344-70.

A disadvantage of the known device is the limited use, narrow specialization (only for cylindrical surfaces) and low productivity, while to obtain high quality it is necessary to create large working forces, and this requires the use of rollers with a large profile radius, which negatively affects the overall dimensions and not always feasible. At the same time, a significant amount of the plastic wave traveling in front of the deforming elements in the form of rollers or balls increases the likelihood of cracking and peeling of the processed surface layer.

The objective of the invention is the expansion of technological capabilities by providing the processing of RPMs of bodies of revolution such as shafts, as well as reducing costs, increasing productivity and improving the quality of production, through the use of deforming elements in the form of spanning rings with an inner working surface consisting of a front cone, a reinforcing belt and a rear cone significantly reducing the magnitude of the plastic wave in front of the deforming elements and the likelihood of cracking and flaking Bani treated surface layer.

The problem is solved by the proposed deforming element for surface plastic deformation of bodies of revolution such as shafts, which is a ring covering a workpiece with a three-stage internal working surface, made in the form of, respectively, sequentially in the direction of the longitudinal feed, the front smoothing cone, the reinforcing belt and the rear cone, and the ring is installed in the bearing with the possibility of free rotation, and its inner diameter is determined by the formulas:

D _ku = (1,1 ... 1,3) D _s ,

D _ku = D _ks -2b

where D _ku is the inner minimum diameter of the hole of the enclosing ring along the reinforcing belt, mm;

D _cc - the inner maximum diameter of the hole of the enclosing ring along the smoothing belt, mm;

D _s - the diameter of the workpiece surface, mm;

b is the value by which the size changes after processing, mm

The essence of the design of the deforming element is illustrated by drawings. Figure 1 presents a diagram of the processing of surface plastic deformation of a non-rigid shaft by deforming female rings as part of a two-ring device for rolling on a lathe, a longitudinal section along AA in figure 2; figure 2 is a two-ring device for rolling in, a General view of the right side along B (rotated) in figure 3; figure 3 is a two-ring device for rolling in, section bb in figure 2; figure 4 is a General side view of a block (consisting of two) holders of a double-ring device in the working position when rolling the shaft; figure 5 is a General side view of a block (consisting of two) holders of a double-ring device in a free state, without a workpiece; in Fig.6 is a block (consisting of two) holders of a double-ring device with an indication of the direction and place of action of the rolling forces, left view in Fig.4; in Fig.7 - block holders indicating the direction and place of action of the rolling forces, a longitudinal section along G-G in Fig.6; in Fig.8 - two-ring device, a section DD in Fig.3.

The proposed female ring is intended for processing by surface plastic deformation (PPD) - by rolling in bodies of revolution such as shafts as part of single and multi-ring devices.

The features of the device and the operation of the ring, we consider the example of a two-ring device for rolling, shown in figure 1-10. The double-ring device comprises a body 1 of a welded structure, with which it is mounted, for example, on a support of a lathe. In the housing you can distinguish: half disk 2, located vertically, two mutually perpendicular horizontal strips 3 for fixing the housing in the tool holder of the caliper (not shown) and stiffeners 4.

Surface plastic deformation is carried out by freely rotating deforming elements in the form of covering rings 5 in an amount of at least two, which are mounted on bearings 6 in the central holes of the holders 7. The holders 7 (in the amount equal to the number of deforming rings — the holder block) freely contact each other with their end surfaces, while in the peripheral diametrically opposite grooves 8 of the holders there are two compression springs 9 common to all the holders, creating the necessary force rolling in P _about . Compression springs 9 are installed in the grooves 8 on the strips 10, which are the supporting platforms for the springs and at the same time limiters of the lateral movements of the holders 7, made under the action of the springs 9, when changing the workpieces and removing them from the rolling zone of the double-ring device (Fig. 5).

The holder block 7 is movably mounted in the housing 1 using two disks 11 and 12. The disks 11 and 12 have central openings for free passage of the workpiece. The disk 11 is rigidly connected to the half-disk 2 of the housing 1 by screws 13, and the other disk 12 is rigidly attached to the end of the disk 11 with the spacer sleeves 14 and screws 15. Between the disks 11 and 12 along the sliding fit (H7 / h6) with a gap, the holder block is freely installed 7 with the help of extensions in the form of tension springs 16. The springs 16 are fixed at one end to the holders 7 and the other are fixed to the spacer sleeves 14. Spring extensions can be installed on each holder, or on one, due to the fact that all holders are combined into a block by compression springs 9.

The assembly of the two-ring device is carried out in the following sequence. To the housing 1, welded from separate elements: half-disk 2, straps 3 and stiffeners 4, screws 13 are attached by screws 13. The holder block 7 is separately assembled. The assembly of the holder 7 assembly consists in installing a bearing 6 in each holder 7 and a deforming element - ring 5 and their connection in the unit by installing compression springs 9, which are compressed into the peripheral grooves 8 of the holders 7, and the fixing of the stretch marks - springs 16.

The general assembly of the two-ring device is completed by installing the disk 12 and fixing it with the help of the rollers 14 with screws 15, with the preliminary installation between the disks 11 and 12 of the holder block 7 assembly, the tension is made, the springs 16 are fixed on the rollers 14 and the brackets 25 with the screws 24 .

At the end of the assembly, a check is made and, if necessary, adjustment of the gaps between the disks 11 and 12 and the holder block 7 by installing washers (not shown) between the rollers 14 and the disk 11 with the aim of free lateral displacement of the holder block 7 relative to the disks 11 and 12 without backlash.

The work of a two-ring device is as follows.

When finishing surface plastic deformation by rolling in, the shaft 17, which has undergone preliminary, for example, turning, is fixed in the chuck 18 of the spindle 19 of the headstock 20, a two-ring device is brought in, the free end of the shaft blank is inserted into the hole of the tool, and the center 21 of the tailstock 22 is pressed. Certain difficulties represents the introduction of the workpiece into the hole of the two-ring device. Since the hole formed by the deforming rings of adjacent free-standing holders will be smaller than the workpiece diameter to be machined, it is necessary to radially spread the holders, overcoming the resistance of the compression springs 9. The holders 7 can be pulled apart in several ways: due to the longitudinal feed and forced separation of the holders due to the chamfer 23, available on the workpiece, with a special lever tool in the form of scissors (not shown) or the method shown in Fig. 8, in which the lateral displacement is held c 7 is performed by adjusting screws 24 set against the respective holders, by screwing them into strips 25 which are secured in the slots 11 and the disc 12.

The processed shaft is informed of a rotational motion V _s . The speed of rotation of the workpiece is set depending on the required performance, design features of the workpiece and equipment. Usually the speed is 30 ... 150 m / min.

определяют по формуле:

,Double ring device report longitudinal feed S _straight in one direction. Optimum feed

determined by the formula:

,

where k is the number of deforming elements; S _e - supply to one deforming element is adopted for deforming covering rings, which are in cross section - a torus with radius R _y on the inner surface (Fig.9).

The presence of the elastic element 9 provides a constant rolling force at any point on the surface to be treated. Setting the required breaking-in force is carried out by changing the compression springs 9.

In a two-ring fixture, the rings are offset along the axis relative to each other, which ensures better processing quality [1].

The use of a female ring as a deforming element allows processing with improved roughness and quality and with greater productivity due to the following. When considering the shape and size of the contact of the deforming ring with the workpiece (Fig. 10), it can be noted that it occurs over a certain area, much larger than when it is rolled around with traditional rollers or balls, and the shape of the boundary of the non-force deformation changes, namely, the deforming the surface of the ring is enveloping and close in geometric parameters to the machined surface of the shaft. This allows you to prevent the appearance of a transverse plastic wave, shown in figure 10, going in front of the contact with the deforming element in the transverse direction, which reduces the likelihood of cracking and peeling of the treated surface layer.

The inner working surface of the ring covering the workpiece is made of a three-stage, where each step is:

the first step is a front smoothing cone with a height of B _s , diameter D _kc and a taper angle α _c = 4 ... 7 °, the purpose of which is to prevent the appearance of a plastic wave (schematically shown in Fig. 9), going in front of the contact of the workpiece with a reinforcing belt deforming element in the direction of the longitudinal feed, which reduces the likelihood of cracking and peeling of the treated surface layer;

the second stage is a working profile for hardening processing, which from the front smoothing cone has the shape of a torus with a profile radius R _y , smoothly turning into a cylindrical girdle with a height B _{y and a} diameter D _k ;

the third step is a rear cone with a height B _os diameter D _ku and a reverse taper angle α _о = 1 ... 3 °, the purpose of which is to prevent the appearance of a residual plastic wave coming after the deforming element contacts the workpiece, which improves the surface roughness.

The steps of the ring are arranged sequentially in the direction of longitudinal feed, and the inner working diameter of the hole of the ring depends on the diameter of the workpiece and is determined by the formula:

D _ku = (1,1 ... 1,3) D _s .

The inner minimum diameter of the opening of the enclosing ring along the reinforcing belt is related to the internal maximum diameter of the opening of the enclosing ring along the smoothing belt by the following relation: D _ku = D _ks -2b

where D _ku is the inner minimum diameter of the hole of the enclosing ring along the reinforcing belt, mm;

D _cc - the inner maximum diameter of the hole of the enclosing ring along the smoothing belt, mm;

D _s - the diameter of the workpiece surface;

b is the value by which the size changes after processing, mm

The proposed ring, as noted above, on the outer surface is installed in the bearing and has the possibility of free rotation, and the desired results are achieved in one working passage in one direction.

The combination of toroidal and cylindrical parts in the second stage of the ring (R _y = 5 ... 200 mm; D _ku = 40 ... 200 mm) allows us to achieve high demands on the roughness of the treated surface.

The performance of the rolling process is determined by the radius of the profile R _y and the height B of _the cylindrical belt ring. Rings with a large profile radius R _y and a height B _y allow machining with a high feed rate (up to 2.5 mm / rev), however, in this case, to obtain a high surface quality it is necessary to create large working forces. The ring parameters depend on the value of the permissible working force. The greater the height B of _the cylindrical girdle, the greater the feed rate. In the treatment of massive parts on large machine tools belt B _have to do more extensive (more than 12 ... 15 mm) as well as how to handle such details to the big speeds is quite difficult, and a large supply can be applied with success. For processing parts of less rigidity, when the rolling force should not be large, apply rings with a belt with a width of 2 ... 5 mm. The installation of rings with a cylindrical belt on the machines is difficult. To ensure their correct position, special devices are used (for an example of one of them, see Figs. 1-10) with self-aligning devices. The height of the belt B _y in this case is 15 ... 40 mm, the feed is 5 ... 15 mm / rev. Rings are made of steel: alloyed ShKh17, KhVG, 9Kh, 5KhNM, carbon tool U10A, U12A, high-speed R6M5, P9, VK8 hard alloy. Hardness of the working surface of rings made of HRC 62 ... 65 steel. The parameter of the surface roughness of the working profile R _a = 0.32 μm.

When switching to processing another shaft size in the fixture, it is enough to replace the holder block and deforming elements.

определяли по формуле

и принимали

, где k=2 - количество деформирующих колец в инструменте, высота деформирующих колец - 12 мм, высота упрочняющего пояска B_у=4 мм. Усилие обкатывания составляло около ≈1700 Н, глубина наклепанного слоя находилась в пределах 0,15...0,20 мм; величина, на которую изменился размер после обкатки - 0,01...0,02 мм; смазывающе-охлаждающей жидкостью при обкатывании служил сульфофрезол (5%-ная эмульсия).Example. A non-rigid shaft was machined by rolling, which had the following dimensions: total length - 1282 mm, length of the working part - 1208 mm, diameter of the shaft cross section - D = 27 ^-0.05 mm, roughness R _a = 0.4 μm; material - steel 18HGT GOST 4543-74, hardness HB 207 ... 228, weight - 5.8 kg. Preliminary processing by turning and finishing processing by rolling was carried out on a mod screw-cutting lathe. 16K20, the peripheral speed of the workpiece - v _s = 84.78 m / min (1.41 m / s), n _s = 1000 rpm, longitudinal feed

determined by the formula

and took

where k = 2 is the number of deforming rings in the tool, the height of the deforming rings is 12 mm, the height of the reinforcing belt B _y = 4 mm. The breaking-in force was about ≈1700 N, the depth of the riveted layer was in the range 0.15 ... 0.20 mm; the size by which the size has changed after running-in - 0.01 ... 0.02 mm; Sulfofresol (5% emulsion) served as a lubricant-cooling fluid during the run-in.

мин по базовому варианту при традиционном шлифовании с помощью шлифовальной головки с последующим полированием абразивной лентой ЛВТ 2200х55 Э4, 5-8-10 ГОСТ 12439-79 на токарном станке 1К62 на АО "Ливгидромаш"). Контроль проводился скобой индикаторной с индикатором ИЧ 10 Б кл. 1 ГОСТ 577-68. При контроле партии обработанных валов в количестве 10 шт. брак не обнаружен.The required surface roughness and accuracy was achieved after T _m = 3.15 min (against

min according to the basic version with traditional grinding using a grinding head followed by polishing with an abrasive belt ЛВТ 2200х55 Э4, 5-8-10 GOST 12439-79 on a lathe 1K62 at AO Livhydromash). The control was carried out by an indicator bracket with an indicator ICh 10 B cells. 1 GOST 577-68. When controlling a batch of processed shafts in the amount of 10 pcs. marriage not found.

The advantages of the proposed deforming covering rings for rolling in bodies of revolution are:

- the ability to run in non-rigid workpieces with an increase in machining accuracy (by 10 ... 20%) due to the rigid design of deforming elements (shape deviation no more than 10 ... 30 microns);

- run in at maximum feeds in comparison with known deforming elements;

- reduction of the error of the previous processing;

- an increase in the contact spot, due to which a higher quality of processing is achieved;

- to form certain macro- and microgeometric forms of the treated surface, reduce roughness parameters - smooth surfaces, change the structure of the material - surface hardening and create a certain stress state, favorably affecting wear resistance.

Thanks to the use of enveloping rings as deforming elements, the amount of plastic wave in front of the deforming elements is significantly reduced, and the likelihood of cracking and peeling of the processed surface layer is negated, and the use of the same machine on which the workpiece surface was pre-treated extends the technological capabilities of processing PPD non-rigid and eccentric shafts, and also reduces the cost of processing, increases productivity It improves the workmanship.

The proposed deforming tool for blanks of bodies of revolution such as shafts is simple to implement, not complicated in design and reliable in operation. The structural layer obtained on the surface of the workpiece has increased hardness and, accordingly, wear resistance and resistance to fatigue failure.

The use of an annular female deforming tool allows to increase the processing productivity by 1.5 ... 2.0 times and to ensure high accuracy and quality.

Information sources

1. A.S. SU 1764971 A, B 24 V 39/04. Device for pulling parts. 09/30/1992 - a prototype.

2. Reference technologist-machine builder. In 2 vols. T.2 / Ed. A.G. Kosilova and R.K. Meshcheryakova. - 4th ed., Revised. and add. - M .: Mechanical Engineering, 1985. S.387-389, Fig. 6, Table 3.

Claims (1)

A deforming element for surface plastic deformation of bodies of revolution such as shafts, which is a ring enclosing a workpiece with a three-stage internal working surface made in the form of, respectively, sequentially in the direction of the longitudinal supply of the front smoothing cone, the reinforcing belt and the rear cone, characterized in that the ring is installed in the bearing with the possibility of free rotation, and its inner diameter is determined by the formulas D _ku = (1.1 ... 1.3) D _s ; D _ku = D _ks -2b, where D _ku is the inner minimum diameter of the hole of the enclosing ring along the reinforcing belt, mm; D _cc - the inner maximum diameter of the hole of the enclosing ring along the smoothing belt, mm; D _s - the diameter of the workpiece surface, mm; b is the value by which the size changes after processing, mm

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