RU2332294C1 - Device for surface plastic deformation processing of spherical surfaces - Google Patents

Abstract

FIELD: technological processes.

SUBSTANCE: invention pertains to the technology of machine building, and particularly to processing work pieces by surface plastic deformation. The device has a case in the form of a holder with a central opening and a deforming instrument. The deforming instrument is made in form of at least three bushes with an inner working surface: at least one of the first bush, at least one middle bush and the last bush. The indicated bushes are pressed onto the central opening of the holder and have a longitudinal groove for free passage of the neck of the work piece. The inner working of the first and middle bushes is made in form of a splined surface. The splined surface of the middle bush is displaced in the peripheral direction on one spline relative the splined surface of the first bush. The inner working surface of the last bush is in form of a smooth cylindrical surface.

EFFECT: high quality and accuracy of processing spherical work pieces by surface plastic deformation.

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Description

The invention relates to mechanical engineering technology, in particular to devices and methods for hardening, calibrating and deforming drawing of metal spherical surfaces of parts, for example automobile ball fingers, from steel and alloys by surface plastic deformation (PPD).

A device for processing surface plastic deformation of workpieces having a spherical surface and a neck associated with it, comprising a body in the form of a cartridge with a central hole [patent RU 2188115 C1, B24B 39/04, 08/27/2002].

The device is characterized by limited capabilities, low efficiency and productivity, not a large depth of the hardened layer and not a high degree of hardening of the treated surface, complexity, high energy and metal consumption of the structure, as well as overall dimensions.

The objective of the invention is to increase productivity, quality and accuracy of processing the spherical surface of the workpiece, as well as expanding the technological capabilities of PPD through the use of the original design of the deforming device, which allows you to control the depth of the hardened layer, the degree of hardening and the microrelief of the processed spherical surface.

The problem is solved using the proposed device for processing surface plastic deformation of workpieces having a spherical surface and a neck associated with it, containing a body in the form of a cartridge with a central hole, while it is equipped with a deforming tool for processing the workpiece with an interference fit in the form of at least three bushings with an inner working surface: at least one first sleeve, at least one middle sleeve and the last sleeve, these bushings are pressed into the central th hole of the cartridge and have a longitudinal groove for free passage of the neck of the workpiece, the inner working surface of the first and middle bushings is made in the form of a splined surface with dimensions d _OUT and d _VP , the splined surface of the middle sleeve is displaced in the circumferential direction by one slot relative to the splined surface of the first sleeve, the inner working surface of the last sleeve is made with a smooth cylindrical surface from the condition of calibrating the spherical surface of the workpiece in size d _SF , while the diameters of the inside The early working surfaces of the bushings are determined from the following expressions:

d _protr = d _zag -2 · 0.8 · t; d _VP = d _zag ; d _sf = d _zag -2 · t,

where d _zag is the outer diameter of the spherical surface of the workpiece, mm; d _lug - the inner diameter of the bushings on the protrusions of the slots, mm d _VP - the inner diameter of the bushings along the slots of the slots, mm; t is the interference, mm; d _SF - the outer diameter of the spherical surface after processing, mm

The essence of the proposed device is illustrated by drawings.

Figure 1 presents a diagram of the processing of PPD of the spherical surface of a spherical automobile finger, which shows the final position of the workpiece before leaving the zone of contact with the tool; figure 2 is a top view of a in figure 1; figure 3 - section B - B in figure 1; figure 4 - section B - In figure 1; figure 5 - section G - G in figure 1; 6 is a diagram of a divided plastic deformation between three bushings.

The proposed device is used for processing PPD metal spherical surfaces, for example, in the globular automobile fingers 1 and other parts of steel and alloys. The workpiece is installed, based and fixed in the device 2 with the possibility of rotation of it relative to the longitudinal axis.

Deforming tool 3 is a set of bushings, pressed into the cartridge 4, mounted, for example, on a vertical broaching machine (not shown). The cartridge 4 with a deforming tool 3, consisting of several working sleeves 5, 6 and 7, makes a feed movement S _CR in the direction perpendicular to the longitudinal axis of the workpiece 1, while the workpiece makes a rotational movement V _s relative to its longitudinal axis.

Deforming sleeves 5, 6, 7 in an amount of at least three have a longitudinal groove for free passage of the neck 8 of the workpiece, mating with a spherical surface 1. The inner surface of the holes of the sleeves 5, 6, 7 is working and has a shape depending on the purpose:

- the first contact with the workpiece sleeve 7 (or more sleeves) is used to pre-FPD and has a splined surface with dimensions d _Venue - inner diameter of spline bushings protrusions slot, d _sn - inner diameter of spline bushings depressions slot, b _br, - the width of the slot and b _VP is the width of the depressions;

- the middle sleeve 6 in contact with the workpiece (or several bushings) also serves as a preliminary PPD and has a spline surface with the same dimensions d _protr , d _vp , b _w and b _vp but displaced in the circumferential direction relative to the first sleeve by one slot;

- the last sleeve 5, which ends the processing of the workpiece 1, serves for the final PPD and has a smooth cylindrical surface that calibrates the spherical surface of the workpiece in size d _sf .

The inner diameters of the spline holes of the bushings are determined from the following expressions:

d _VP = d _zag ; d _protr = d _zag -2 · 0.8 · t; d _sf = d _zag -2 · t,

where d _zag is the outer diameter of the spherical surface of the workpiece, mm;

d _Venue - inner diameter of the bushings protrusions slot, mm

d _VP - the inner diameter of the bushings on the slots of the slots, mm:

t is the interference, mm;

d _SF - the outer diameter of the spherical surface after processing, mm

The width of the slots on the bushings 6 and 7 is slightly larger than the width of the depressions and is taken equal to b _W = 1,1 · b _VP .

The bushings 5, 6, 7 are sequentially sealed in the cartridge 4, guaranteed against turning by press fit and setting the keys 9. From below (according to FIG. 1), the cartridge 4 is closed by a cover 10.

The main technological parameter of the PPD process is an interference fit t, which is provided by a divided plastic deformation scheme between, for example, three deforming bushings 5, 6, 7.

When passing the sleeve 7 from top to bottom (according to FIG. 1) and rotating the workpiece around its own longitudinal axis, traces of indenting the slots (pos. ₇ , Fig. 6) are formed over an area slightly more than half the entire surface of the sphere. The remaining part of the sphere is treated with slots of the next sleeve 6 (pos. T ₆ , Fig.6).

Thus, the preliminary PPD of the entire spherical surface is made sequentially by two bushings. With large diameters of the sphere, the preliminary PPD process of the entire spherical surface can be performed sequentially with several bushings. However, traces of alternating processing with two bushings remain on the surface of the sphere. Therefore, a sleeve 5 is provided for the final PPD (pos. ₅ , Fig. 6), which is made with a smooth inner working surface having a final, final size d _sf .

The inner surface of the bushings has straight slots as the most technologically advanced in the manufacture, for example, by pulling or chiselling, however, the slots can be made with screw.

The divided scheme of plastic deformation allows us to reduce forces in case of RPM and their effects on the rotation mechanism of the workpiece, which increases the life of the tool and equipment as a whole and positively affects accuracy and productivity.

For complete processing of the spherical surface, the workpiece at the moment of movement along the sleeve rotates with an overturn by 1.15 ... 1.25 turns relative to its own axis. Thus, when moving the cartridge over the entire total length of three bushings, the workpiece rotates by 3.5 ... 4 turns.

When processing with an interference fit of t up to 0.5 mm, shape deviations in the cross section (deviation from roundness) are reduced, size accuracy is increased by 30 ... 35%, and surface roughness parameters are reduced. With such interference, workpieces are also treated after heat treatment.

The total interference is limited by the ductility of the workpiece material. Billets made of brittle materials are processed with small tightnesses, since with high tightness it can break.

Processing with bushings provides optimal conditions for deformation, and the tool has the maximum dimensional stability.

The material of the bushings is VK8 hard alloy and other wear-resistant tool materials. The radial runout of the working surface of the sleeve bore should not exceed 0.02 ... 0.05 mm.

When processing the proposed device must be used lubricant-cooling technological tool (COTS), preventing the setting of the sleeve with the processed metal. The absence of COTS leads to the rejection of workpieces and often to the destruction of the tool. For billets of carbon and low alloy steels are recommended: sulfofresol, MP-1, MP-2, emulsions. The same liquids should be used in the processing of blanks from non-ferrous metals (bronze, brass, aluminum alloys). For parts made of high alloy, heat-resistant and corrosion-resistant steels and alloys, the following SOTS should be used: АСМ-1, АСМ-4, АСМ-5, АСМ-6. When machining billets of hardened steels, ASF-3 grease is used.

The roughness of the surface treated by the proposed device depends on the initial roughness and material of the workpiece, the processing mode used by SOTS. The roughness of the treated surface does not depend on the processing speed (within the range of applied speeds). To obtain small values of the roughness parameters, it is advisable to pre-treat the outer spherical surface with a carbide tool, for example, a cutter with small angles in the plan (φ = 30 ... 40 °), at cutting speeds that exclude the formation of growth. When processing the sphere after roughing and finishing turning (initial parameter Ra = 6.3 ... 1.6 μm), surfaces with Ra = 0.8 ... 0.1 μm are obtained if the workpiece material is steel; Ra = 0.4 ... 0.1 μm when processing billets of bronze and Ra = 1.6 ... 0.4 μm when processing billets of cast iron.

The surface roughness after plastic deformation of the proposed device will be the lower, the less the interference at which the processing of the sphere. So, when processing a workpiece made of steel 45 with an initial roughness of Ra = 4 ... 8 μm, we obtained the following roughness with interference on a deforming tool:

Preload t, mm 0.05 0.10 0.20 0.30 0.50 Parameter Ra, μm 0.06 0,07 0.4 1.3 3.0

Hardening of the metal is a consequence of the occurring deformations. The hardening, expressed by a change in hardness, decreases with the transition from the machined surface to the depth of the billet sphere. The thickness of the texture layer with increased hardness is greater, the greater the interference and the less, the higher the initial hardness of the processed metal. The increase in hardness depends on the metal being processed and is 130 ... 250%. The speed of the rotational movement of the workpiece V _{s is} assigned within 2 ... 25 m / min.

To achieve accuracy in 11 ... 13th qualifications, processing is carried out with great interference. To achieve accuracy in the 8 ... 11th qualifications, medium tightness (0.2 ... 0.5 mm) should be applied. To obtain accuracy according to the 5 ... 6th qualifications, preliminary precise machining is necessary, after which the deformation is carried out with small tightnesses (0.02 ... 0.2 mm). For the last group of workpieces, a scheme is advisable: deformation - cutting - thin deformation.

Example. We processed the PPD blank of the ball upper finger 2101-2904187, installed in a special electromechanical device on a vertical-broaching machine mod. 7B65, the proposed device. The blank is made of steel 20X GOST 1050-74. Processed a sphere with a diameter of 32.7 ± 0.1; the initial roughness parameter Ra = 3.2 μm, achieved - Ra = 0.63; a deforming tool in the form of bushings made of VK8 hard alloy in the following modes: workpiece rotation speed V _s = 5 m / min (n _s = 50 min ^-1 ); the speed of the longitudinal feed of the deforming tool S _CR = 0.2 m / min; total tightness on diameter - 0.2 mm (0.1 mm per side); the depth of the layer of high hardness was 0.15 ... 0.20 mm; Sulfofresol (5% emulsion) served as the cutting fluid.

The required roughness and accuracy of the spherical surface was achieved with one pass in T _m = 0.1 min (against T _m ^bases = 2.75 min according to the basic version in the traditional ball rolling treatment at the Oryol Steel Mill OSPAZ). The control was carried out by an indicator bracket with an indicator ICh 10 B cells. 1 GOST 577-68 and on the profilometer mod. 283 type AII GOST 19300-86. In the processed batch (equal to 100 pieces), no defective parts were found. The deviation of the treated surface from sphericity was not more than 0.02 mm, which is acceptable TU.

The processing showed that the roughness parameter of the treated spherical surfaces decreased to Ra = 0.32 ... 0.63 μm with the initial value Ra = 3.2 ... 6.3 μm, the productivity increased by more than five times compared to traditional run-in. The energy intensity of the process decreased by 2.2 times.

The proposed device improves the productivity, quality and accuracy of processing the spherical surface of the workpiece, and also expands the technological capabilities of the PPD through the use of the original design of the deforming tool and allows you to control the depth of the hardened layer, the degree of hardening and the microrelief of the processed spherical surface.

Claims (1)

A device for processing surface plastic deformation of workpieces having a spherical surface and a neck associated with it, comprising a body in the form of a cartridge with a central hole, characterized in that it is equipped with a deforming tool for processing the workpiece with an interference fit in the form of at least three bushings with an inner working surface : at least one first sleeve, at least one middle sleeve and the last sleeve, these sleeves are pressed into the Central hole of the cartridge and have a longitudinal for the free passage of the neck of the workpiece, the inner working surface of the first and middle bushings is made in the form of a splined surface with dimensions d _protr and d _vp , the splined surface of the middle bush is displaced in the circumferential direction by one slot relative to the splined surface of the first bush, the inner working surface of the last bush is made with a smooth cylindrical surface from the condition that the spherical surface of the workpiece is calibrated to size d _sf , while the diameters of the inner working surfaces of the bushings are determined Elena from the following expressions: d _protr = D _zag -2 × 0.8 × t, d _vp = d _zag , d _sf = d _zag -2 × t, where d _zag is the outer diameter of the spherical surface of the workpiece, mm; d _lug - the inner diameter of the bushings on the protrusions of the slots, mm d _VP - the inner diameter of the bushings along the slots of the slots, mm; t is the interference, mm; d _SF - the outer diameter of the spherical surface after processing, mm

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