RU2416481C1 - Method of static pulse spinning - Google Patents

Abstract

FIELD: process engineering.

SUBSTANCE: invention relates to metal forming, particularly, to rotary drawing of cylindrical shells, hollow articles and, to static pulse spinning. Spinning tool is fed in crosswise direction relative to revolving workpiece. Additionally said spinning tool is fed in lengthwise direction after each dual return-cross stroke. Note here that spinning tool comprises body with spinning elements to act on workpiece with interference. Note here that said body represents "П"-like box with lengthwise slot for workpiece to pass therein unobstructed. Note that spinning elements represent "П"-like spring clips rigidly fitted in the body on opposite walls. Distance between mating pairs at the start of cross feed in direction perpendicular to workpiece lengthwise axis is equal to workpiece OD, while, at the stroke end, is equals to OD of finished part. Note also that total interference equal to half the difference between said ODs is distributed among all pairs of spinning elements. Mind that a section of spinning tool is made up of sleeve sliding on clip crossarm.

EFFECT: expanded processing performances, higher quality and efficiency.

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Description

The invention relates to the processing of metals by pressure, in particular to methods of forming a relief on hollow products, as well as for rotational drawing and pressure treatment of shells.

A known method implemented by pressure rollers, the nature of the course of the processing process which depends on the radius of rounding and the width of the belt [1]. However, the disadvantage of the known method carried out by pressure rollers is the difficulty of restoring the shape as a result of wear, as this requires grinding all external surfaces with a change in grinding radii to maintain a radius mate. At the same time, adjustments are required in the technological modes. In addition, the disadvantage is the 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, increasing the contact surface that interacts with the workpiece and provides a high roughness of the finish of the processed surface, which determines the high quality of the surface and does not require a large number of technological transitions, which dramatically increases productivity, improves deformation conditions and metal flow, and also reduces the likelihood expansion, swelling of metal and the occurrence of scoring on the treated surface, increasing davilnjami resistance tool.

The problem is solved by the proposed method, designed for static-pulsed pressure processing of hollow products, including a message to the deforming tool of the transverse feed relative to the axis of the rotating workpiece, while the multi-element deforming tool is additionally informed of the longitudinal movement after each double reciprocal-transverse stroke of the tool containing the body with deforming elements for impact on the workpiece with an interference fit, while the body is made in the form of a U-shaped box with a native groove for the free passage of the workpiece, and the deforming elements are made in the form of U-shaped spring brackets, rigidly sealed inside the case on opposite walls against each other, with the distance between the corresponding pairs at the beginning of the transverse feed movement when the workpiece contacts the tool in the direction perpendicular to the longitudinal axis of the workpiece, equal to the outer diameter of the workpiece, and at the end of the movement, to the outer diameter of the finished part, with a total tightness equal to half the difference in diameter of the blank ovki and finished parts, distributed uniformly on all the pairs of deforming elements, the working part of the deforming element is designed as a sleeve slidably mounted on brackets on the bar.

Features of the proposed method, implemented by a pressing tool, are illustrated by drawings.

Figure 1 presents a diagram of the pressure treatment of PPD of the cylindrical surface of a hollow product by the proposed method and tool, a partial longitudinal section of a tool, a top view along A in figure 2; figure 2 - diagram of the press machining and tool, side view, longitudinal section, which shows the initial longitudinal working position of the tool and the final; figure 3 is a processing diagram of the proposed method and the tool, a left view according to B in figure 2, which shows the intermediate position of the workpiece relative to the tool, and also conditionally thin lines show the initial (top) and end (bottom) position of the workpiece; figure 4 - sequence diagram of the cycle of movements of the tool, where indicated: S _POP - transverse working movement of the tool relative to the workpiece; S _{XX -} transverse idle movement of the tool relative to the workpiece; S _PR - longitudinal working movement of the tool relative to the workpiece.

The proposed method is intended for static-pulse pressing processing of PPD, calibration, deformation pulling and hardening of metal cylindrical surfaces of 1 hollow parts from steels and alloys. The proposed method, intended for static-pulsed pressure processing of hollow products, includes a message to the deforming tool of the transverse feed S _POP relative to the axis of the workpiece rotating at a speed V _P , while the multi-element deforming tool is additionally informed of the longitudinal movement S _PR after each double reciprocating working and idle S _XX tool strokes,

Installation, basing and fixing of the workpiece 1 with the possibility of rotation relative to its longitudinal axis is carried out using, for example, a special electromechanical device in the form of a mandrel 2, which is installed, for example, on a vertically-broaching machine mod. 7B65.

A pressing tool operating according to the proposed method comprises a housing 3 with deforming elements 4 for impacting the workpiece 1 with an interference fit. The housing 3 is made in the form of a U-shaped box with a longitudinal groove for free passage of the workpiece. The deforming elements 4 are made in the form of U-shaped spring brackets, rigidly embedded inside the housing 3 on opposite walls against each other.

The distance H _Z between the pair of pressure elements 4 (shown conventionally at the top, according to FIG. 3) at the beginning of the feed movement S _POP at the contact of the workpiece 1 with the tool 3 in the direction perpendicular to the longitudinal axis of the workpiece 1, is set equal to the outer diameter of the workpiece before processing.

The distance H _D between the pair of pressure elements 4 (conventionally shown below, according to FIG. 3) at the end of the feed movement S _POP is equal to the outer diameter of the finished hollow part.

The total interference equal to half the difference between the diameters of the workpiece and the finished part is distributed evenly across all pairs of deforming elements.

The distance H _Z and H _D between the respective pairs of pressure elements 4 is regulated by the approach or removal of the opposite walls of the housing 3, which are connected to each other overlap by bolts 3 _B.

The deforming element - the bracket 4 has a working part - a crossbar 4 _P and two racks 4 _C , with which it is mounted in the wall of the housing 3. The working part 4 _{P of the} deforming element, with which the element acts on the workpiece, consists of a 4 _V sleeve installed on a sliding landing on the crossbar of the bracket. The longitudinal axis of the staple bar is parallel to the axis of the workpiece. In order to reduce friction and prevent rapid wear of deforming elements between the 4 _V bushing and the crossbar, for example, a fluoroplastic bushing (not shown) playing the role of a bearing or, alternatively, a needle bearing (not shown) is installed. When the hollow articles made of non-ferrous metals and alloys are pressed, a solid bar without a sleeve is used.

Rigid fastening of the struts of the pressure elements in the walls of the housing is provided, for example, by embossing, flaring, threaded connection using a nut, twisted on the threaded tip of the rack (not shown), or other known methods.

The length L of the walls of the tool body 3 depends on the length of the workpiece being machined l and the length of the working part of the pressing element, i.e. staple bars. The ratio of the lengths of the workpiece to be processed l and the working part of the pressure element affects the number of transverse passages. Figure 4 shows the sequence diagram of the complete processing cycle of one workpiece, consisting of three transverse passes of the tool.

During pressure treatment, the tool body with deforming elements - brackets, rigidly fixed in a chuck, for example, a vertical broaching machine (not shown), moves the feed S _POP in the direction perpendicular to the longitudinal axis of rotation of the workpiece, while the workpiece rotates with respect to its longitudinal axis with speed - V _З.

The deforming elements 4 mounted on the inside of the tool body 3 make a working movement from the bottom to the top (according to FIGS. 1, 2, 3) and cover the cylindrical surface of the workpiece from both sides. When the rotational movement of the workpiece V _W and the translational motion S _{POP of the} deforming elements are combined, dynamic impact with slippage is performed, which allows plastic deformation, drawing and smoothing of the workpiece shell and hardening of the surface layer of the cylindrical surface.

The proposed tool allows to increase the productivity of the pressure smoothing processing, as well as to improve the quality and accuracy of the workpiece.

The main technological parameter of the process is the tightness on each, oppositely located, a pair of deforming elements, mm:

i _E = (H _C -H _D ) / n,

where H _Z - the distance between the upper pair (according to figure 3) of the deforming elements, equal to D _Z - the diameter of the cylindrical surface of the workpiece before processing (arithmetic average taking into account the deviations of the shape in the cross section), mm;

H _D - the distance between the pair of lower (according to figure 3) deforming elements equal to D _D - the diameter of the cylindrical surface of the machined part, mm;

n is the number of pairs of corresponding deforming elements on the sides of the tool, provided that the number of elements on each side is the same.

When processing with interference davilnjami i _E 0.2 ... 0.5 mm for each pair disposed diametrically, the deformation elements are reduced deflection shape in cross section (deviation from roundness) and increases the size of the accuracy of 30 ... 35%, the surface roughness parameters decrease .

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

Processing by deforming spring elements in the form of brackets provides optimal conditions for deformation - the tool has maximum dimensional stability.

Deforming elements in the form of spring brackets are made of steel: alloyed ШХ15, ХВГ, 9Х, 5ХНМ, carbon tool U10A, U12A, high-speed R6M5, P9. Hardness of a working surface of a bracket from HRC 62 ... 65 steels. The roughness parameter of the working profile of the spring clamp is Ra = 0.32 μm.

When processing the proposed method and this tool, a lubricant-cooling technological agent (COTS) is necessarily used, which prevents the setting of the deforming spring-shaped spring with the metal being treated. 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 workpieces made of high alloy, heat-resistant and corrosion-resistant steels and alloys, the following SOTS should be used: ASM-1, ASM-4, ASM-5, ASM-6.

The roughness of the surface processed by the proposed method and the above-considered tool depends on the initial roughness and the 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).

The speed of the transverse feed S _POP deforming elements during processing by the proposed method and this tool is associated with the speed of rotation of the workpiece V _{W the} following ratio:

S _POP = 0.01 · V _Z ,

where S _POP - the lateral feed rate of the deforming elements, m / min;

V _З - speed of the rotational movement of the workpiece, m / min.

The speed of the rotational movement of the workpiece Vz is assigned within 2 ... 20 m / min.

To achieve accuracy in 11 ... 13th qualifications processing is carried out with great interference. To achieve accuracy in 8 ... 11th qualifications, medium tightness (0.3 ... 0.4 mm) should be applied. To obtain accuracy in 5 ... 6th qualifications, deformation is carried out with small tightnesses (0.03 ... 0.3 mm).

As a result of static-pulse rolling and smoothing by the proposed method using this tool, the roughness is improved by one class, the static force of pressing the tool against the workpiece’s work surface is 200 ... 300 N per 10 mm of the tool’s working surface length and depends on the depth of penetration of the pressure element into the workpiece. The choice of the corresponding static-pulse pressure depends on the physicomechanical properties of the workpiece material and on the preload i _E.

The proposed method and this squeezing tool are used on powerful squeezing machines operating by the method of reverse rotation drawing of thick-walled blanks [1]. The radius R _{D of the} cross section of the crossbar of the pressure element depends on the thickness t _{o of the} ironed shell and is taken equal to - R _D = (1 ... 1,5) t _o .

The distance between the walls of the receiving tool of the design considerations in view of the length of racks 4 _C. With a decrease in the length of the uprights, the rigidity of the tool structure increases and the flexibility and deflection of the uprights decreases, while the deformation forces increase.

The surface microrelief formed as a result of static-pulse rolling and smoothing is determined by the following main factors: process kinematics (the direction of mutual movement of the tool and the workpiece being machined); initial roughness; shape and size of the initial part and the rolling tool; 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; vibration of the technological system machine-tool-tool-workpiece.

With static-pulse pressure rolling and smoothing with the proposed female tool on the work surface, the likelihood of longitudinal and transverse waviness sharply decreased due to an increase in the contact area and the use of an elastic pressure element in the form of a bracket, as well as vibrations that occur when the workpiece contacts change from one deforming element to another .

When static-pulse rolling in the shells, the maximum speed is selected within 2 ... 20 m / min, taking into account the power of the machine and vibration resistance of the technological system.

The microroughness height obtained by static-pulse smoothing with this tool is within the permissible maximum value of the microroughness height.

In industrial tests, a workpiece with outer and inner diameters of 126 mm and 122 mm, respectively, 250 mm long — an oil filter cap made in the previous operation by stamping from tape 08YU-OSV-A-II - 2.2 GOST 19851-74, was installed on an expandable cam mandrel, and covering the pressing tool - on the toolholder on a vertical broaching machine mod. 7B65.

The deforming brackets were made of alloyed steel ШХ15, from a wire with a diameter of 3 mm. The hardness of the working surface of the brackets is HRC 62 ... 65. The roughness parameter of the working profile of the staple bar Ra = 0.32 μm. Staple length 50 mm.

Processing was carried out in the following modes: workpiece rotation speed V _З = 20 m / min (n _З = 200 min ^-1 ); lateral feed rate of deforming elements S _POP = 0.2 m / min; total tightness to a diameter of 2.0 mm (1.0 mm per side); interference on the deforming element i _E = (1.0 / 10) = 0.1 mm; the number of deforming elements n = 10; Sulfofresol (5% emulsion) served as the cutting fluid.

Press processing of one product was carried out in 6 passes in T _m = 1.2 min (against T _m ^bases = 3.65 min according to the basic version when processing by traditional rolling in OAO Avtogregat, Livny city).

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 AN GOST 19300-86. No defective parts were found in the processed batch (100 pieces). The deviation of the treated surface from cylindricity was not more than 0.02 mm, which is permissible.

Tests have established that the productivity of the process increases by 2.5 ... 3.3 times compared with smoothing by cylindrical rollers [1], the dimensions of the machined parts are stable and correspond to the required accuracy level, the height of the surface roughness corresponds to Ra 1.6 μm, there was no waviness.

The proposed method, which is implemented with a gripping pressing tool, for static-pulse smoothing is simple to implement, not complicated and reliable in operation, allows to increase the accuracy of manufacturing hollow products, reduce the height of microroughnesses, increase the performance of static-pulse processing, improve the deformation conditions and metal flow, and also reduce the likelihood of expansion, expansion of the metal and the occurrence of scoring on the treated surface, to increase the resistance of the pressing tool.

Using the proposed method and this pressing tool allows you to expand the technological capabilities of static-pulse rolling and smoothing due to the grasping of the workpiece by deforming tool and the imposition of vibrational movements on the tool, to improve the quality, accuracy and productivity of processing, the energy consumption of the process decreased by 2.2 times.

Information sources

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

Claims (1)

A method of static-pulsed pressure processing of hollow products, comprising communicating to a transverse feed tool relative to the axis of a rotating workpiece, characterized in that the deforming tool is additionally informed of longitudinal movement after each double reciprocal stroke, and using a multi-element deformation tool comprising a housing with deforming elements, for impact on the workpiece with an interference fit, while the body is made in the form of a U-shaped box with a longitudinal groove for the rim of the passage of the workpiece, and the deforming elements are in the form of U-shaped spring brackets, rigidly sealed inside the housing on opposite walls against each other, ensuring the distance between the respective pairs at the beginning of the transverse feed movement when the workpiece contacts the tool in the direction perpendicular to the longitudinal axis the workpiece equal to the outer diameter of the workpiece, and at the end of the movement to the outer diameter of the finished part, with a total interference equal to half the difference between the diameters of the workpiece and th oic parts distributed uniformly on all the pairs of deforming elements, the deforming member working part operate as a sleeve mounted for sliding fit on the lintel brackets.

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