RU2421321C2 - Method of vibration rolling - Google Patents

Abstract

FIELD: process engineering.

SUBSTANCE: invention relates to metal forming, particularly, to surface pulsed impact plastic deformation. Billet and multi-element deforming tool are driven to revolve about their axes. Deforming tool is fed longitudinally. Deforming tool is used that comprises body made up of three-phase induction squirrel-cage motor with rotor running in antifriction bearing there inside. Master cam made up of a plate with central bore is fixed on body face. V-shaped bent flat plate springs are fitted into rotor bore. Plate springs have their one end secured rigidly on rotor face and opposite end fitted in master cam central hole for them to be acted on by said ledges and recesses. Deforming elements are arranged to embrace the workpiece.

EFFECT: expanded performances, higher efficiency and quality.

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Description

The invention relates to the processing of metals by pressure, in particular to methods of impulse-impact surface plastic deformation (PPD), and can be used for finishing and hardening of cylindrical hollow products, screw and complex surfaces, for example screw pump pumps, screw surfaces with rounded sinusoidal profile, eccentric journals of shafts, cam surfaces and PK profiles.

There is a method implemented by a three-roller device mounted on a support of a lathe, consisting of a housing and a holder pivotally connected to it with three deforming elements - rollers, which allows to unload the machine components from unilaterally applied force and processing non-rigid parts such as shafts [1]. The hinged connection of the holder with the housing allows to increase the accuracy of the shaft processing and to eliminate the influence of the beating of the shaft surface acquired in previous operations.

The disadvantages of this method are the narrow technological capabilities in which the finishing by surface plastic deformation (PPD) of screw and other complex external surfaces after appropriate modernization is very difficult, and in some cases impossible, while low productivity and complicated long-term setup increase the cost of processing,

A known method and device comprising a housing with an individual high-speed drive, covering the workpiece ring with deforming elements located on the treadmill on the inner surface, and the housing - the ring is mounted in a crank, also having an individual drive, due to which additional planetary rotation about an axis passing through through the center of the workpiece, parallel and offset relative to the axis of the body - the ring by the amount of eccentricity [2, 3].

The disadvantages of this method are the narrow technological capabilities, in which the finish surface plastic deformation of the screw outer surfaces after appropriate modernization is very difficult, and in some cases impossible. In addition, a structurally complex drive consisting of two individual drives increases the cost of processing, reduces productivity, degrades the quality of the machining surface, requires complex and lengthy settings.

The objective of the invention is to expand the technological capabilities of PPD methods for complex surfaces by using a covering tool with deforming elements mounted on flat leaf springs and located on the inner surface of the rotor of the electric motor, which allows to improve the quality of the machined surface, increase productivity and reduce the cost of processing.

The problem is solved by the proposed method of pulse-shock hardening by surface plastic deformation of parts in the form of shafts with complex profiles, which includes communicating to the workpiece and a multi-element rolling deformation tool of rotational movements around its own axes and longitudinal feeding of a multi-element oblique deforming tool, using a multi-element oblique deforming tool comprising a housing with a Central hole, made in the form a stator of a three-phase asynchronous squirrel-cage motor, inside of which a rotor in the form of a hollow shaft with spline grooves on the surface of its hole is mounted on a rolling bearing, a copier in the form of a disk with a central hole, rigidly fixed to the end of the housing, and V-shaped curved flat leaf springs made of steel tape installed in the hole of the rotor, one end of which is rigidly fixed to the end of the rotor, the other end is located in the Central hole of the copier and act on it is made protrusions and depressions located on the surface of the said hole of the copier, and deforming elements are fixed in their middle part, while deforming elements cover the workpiece, and the inner diameter passing through the vertices when the leaf springs are in a free state is less than the diameter of the shaft workpiece by the amount of interference created by means of leaf springs and providing the force of surface plastic deformation.

Features of the method are illustrated by drawings.

Figure 1 shows a diagram of a method using a device for rolling in and hardening a helical surface, a partial longitudinal section; figure 2 is an end view of a in figure 1; figure 3 is a section bB in figure 1; in Fig.4 is an end view of B in Fig.1, flat springs with deforming elements in the rolling position; figure 5 is an end view of in figure 1, flat springs with deforming elements in the impact position.

The proposed method and its implementing device are intended for plastic deformation of screw, cylindrical and other complex profile surfaces (for example, screw pumps, screw surfaces with a rounded sinusoidal profile, cylindrical hollow products, eccentric shaft necks, cam surfaces and PK profiles), work on which consists in the fact that the workpiece deforming tool and report rotational movements _of V and V _and, respectively, the deforming device with conductive reported tool longitudinal feed movement S _ave. The device has deforming elements that inflict numerous blows on the surface of the workpiece, plastically deforming and hardening the outer surface of the workpiece.

For surface pulsed-impact deformation of the workpiece’s work surface, for example, screw pump screw 1 (see Fig. 1), pretreated, for example, by turning, it is fixed in a fixture, for example, in a three-jaw self-centering cartridge with a center tailstock (not shown) and report a rotary motion about its own V _of the central axis, and the shock pulse-deforming tool 2 of the device - V _and rotational movement and a longitudinal pitch s _ave.

The device consists of a housing 3 made in the form of a stator of a three-phase asynchronous squirrel-cage motor, taken, for example, according to GOST 19523-74, with poles 4 and made of gray cast iron. Inside the stator housing 3, on the rolling bearings 5, a rotor 6 is mounted in the form of a hollow steel shaft.

In the spline hole of the rotor 6, V-shaped curved flat leaf springs 7 are installed, made of cold-rolled steel heat-treated tape taken, for example, according to GOST 21996-76. In the middle part of the leaf springs 7 are fixed deforming elements 8, for example balls, rollers, etc.

The leaf springs 7 are located in the spline grooves 9 of the rotor hole and are bolted to one end of the rotor 6 at one end of the rotor 6 with bolts 10. The spline grooves in the rotor hole are designed to transmit rotor torque to the deforming elements and prevent longitudinal twisting of the flat springs, so the latter are tightly seated in the spline grooves .

The other end of the leaf springs 7 is free, located in the slotted grooves of the rotor hole, extends beyond its dimensions and is located in the central hole of the copier 11, made in the form of a disk and rigidly fixed to the end of the housing 3. The central hole of the copier 11 is made in the form of protrusions 12 and depressions 13 Thus, the protrusions 12 and depressions 13 of the copier 11 act on the free end of the flat spring 7 when the rotor 6 rotates, turning free rolling into a pulse-impact surface plastic deformation (PPD) with a reinforcing effect ohm

The number of deforming elements 8 is chosen for structural reasons and taking into account that they cover the workpiece 1.

The inner diameter "d" at the tops of the deforming elements 8, mounted on leaf springs 7, which are in a free state without a workpiece, is less than the workpiece diameter D _{1 to be} processed by the amount of interference that determines the rolling force when the end of the leaf spring is in the hollow of the copier. The force P of the pulse-impact action of the deforming elements 8 on the workpiece surface 1 is set by the difference "K" of the protrusion 12 over the cavity 13 and the stiffness of the springs (see figure 5).

The proposed method, implemented by this device, and mounting the deforming tool 2 in the hole of the shaft of the rotor 6 of the electric motor mounted, for example, on the transverse support of the lathe (not shown), allows oscillatory movements of the deforming elements 8, mounted on leaf springs 7, realizing a pulse shock plastic deformation of the surface layer of the workpiece.

The kinematic transmission of the rotational motion V _{and the} rotor shaft 6 with deforming elements 8 is carried out by means of electric forces induced in the housing - the stator of the electric motor and is minimal in length and complexity and eliminates the use of intermediate belt, gear and other gears and reducers, therefore, the proposed method and device have high efficiency.

In order to create a force P for a pulse-impact surface plastic deformation, a copier is installed that exerts pressure on the leaf springs and, accordingly, on the deforming elements 8 in the transverse direction. The movable fastening of the deforming elements 8 on the leaf springs 7 is carried out by known methods.

The hardness of the surface layer, the depth of hardening and surface roughness obtained by the proposed method using the considered device depend on the impact force and the number of impacts per 1 mm ^{2 of the} surface. These parameters, in turn, depend on the peripheral speed of the rotor shaft with deforming elements 8, interference, the size of the deforming elements, their number, rotation speed of the workpiece, the magnitude of the longitudinal feed of the tool and the number of passes.

Modes of pulse-impact deformation of the proposed method using a device equipped with, for example, balls with a diameter of 5 ... 10 mm and steel billets, the following: the peripheral speed of the rotor shaft is V _and ≈0.05 ... 1.5 m / s, the peripheral speed of the workpiece is V _s ≈20 ... 40 m / s, the number of passes - 2 ... 3, the interference - 1.1 ... 2.5 mm.

As a result of pulse-impact plastic deformation of microroughnesses and the surface layer of the proposed method, the surface roughness parameter increases to Ra = 0.08 ... 0.4 μm with the initial value of Ra = 0.8 ... 3.2 μm. The hardness of the treated surface increases by 25 ... 75% with a riveted layer depth of 0.25 ... 2.5 mm. The residual compressive stresses reach 350 ... 750 MPa on the surface.

Pre-treatment of the workpiece: grinding to a roughness parameter value Ra = 0.4 ... 1.6 μm, as well as finishing turning of surfaces with a roughness Ra = 3.2 μm.

The method and device for pulse-impact deformation allows you to create a regular microrelief on the complex surface to be processed that can hold lubricants and extend the life of parts during operation.

The method and device for pulse-impact deformation is used in the manufacture of blanks from non-ferrous metals and alloys, cast iron and steel with hardness up to HRC 58 ... 64.

In industrial tests of the method, the developed device was installed in a cartridge with an electromechanical drive on a lathe mod. 16K20F3 and processed the screw blank of the left H41.1016.01.001 screw pump of the EVN5-25-1500 brand, which had the following dimensions: total length - 1282 mm, length of the screw part - 1208 mm, cross-section diameter of the screw - ⌀ 27 ^-0.05 mm , eccentricity - 1.65 mm, pitch - 28 ^{± 0.01} mm, roughness Ra = 0.4 μm; single-helical screw surface, left direction; material - steel 40X, hardness HB 270-280, weight - 5.8 kg. The processing was carried out using the developed device, based on the IM5010 electric motor, having a shaft rotation speed of the rotor n = 750 min ^-1 ; the outer diameter of the rotor shaft is 157.3 mm; the diameter of the hole bored under the tool and the workpiece from 54 mm to 115 mm; length of the housing - stator - 253 mm; the outer diameter of the housing - stator is 261 mm.

Impulse-impact PPD were conducted in the following modes: peripheral tool speed - V _and ≈1.2 m / s; the peripheral speed of the workpiece is V _s ≈15 m / s, the number of passes is 3, the interference fit is 1.2 mm, the longitudinal S _pr feed is 1.5 ... 2.0 mm / rev, the hardening force is 170 ... 175 N; the screw diameter changed after processing by 0.03 mm (0.015 mm per side); the depth of the hardened riveted layer was in the range of 0.15 ... 0.20 mm; hardness increase by 25 ... 30%; during processing, the deforming elements were lubricated with a mixture of industrial oil (60%) and kerosene (40%), the surface of the workpiece with kerosene. The values of technological factors (impact frequency, feed rate) were chosen in such a way as to ensure the multiplicity of impact on the elementary area of the treated surface in the range of 6 ... 10. A further increase in the multiplicity of the deforming effect leads to softening.

The initial roughness parameter Ra = 3.2 μm, achieved - Ra = 0.32 μm; deforming tool - balls with a diameter of 7 mm from steel ШХ 15, hardness HRC 63 ... 65.

The depth of the hardened by pulse-shock processing of the layer is 3 ... 4 times higher than with traditional rolling. The hardened layer in the traditional static rolling is formed under long-term action of large static forces.

The proposed method, a similar depth of the hardened layer is achieved as a result of short-term pulse-impact impact on the deformation zone of the energy pulse.

The required roughness and accuracy of the screw surface was achieved after T _m = 3.45 min (against T _m ^bases = 10.6 min according to the basic version with traditional rolling of screws on a 1K62 lathe at OAO Livhydromash).

To ensure the required quality and dimensional accuracy of the processing, the main time was 3 times less than when rolling in with a traditional obkatnik. In this case, the depth and microhardness of the hardened layer (white zone) were 0.20 ... 0.25 mm and 8 ... 9 GPa, respectively, with a gradual decrease in microhardness in depth to the initial state - 2.0 ... 2.5 GPa.

The control was carried out by an indicator bracket with an indicator ICh 10 B cells. 1 GOST 577-68. The cumulative error between any non-adjacent steps was not more than 0.1 mm, the clearance when controlling the straightedge of the protrusions forming in diameter was not more than 0.07 mm, which is permissible according to the technical specifications.

Studies of the stress state of the hardened surface layer by pulse-shock processing showed that the maximum residual stresses are close to the surface, as when chasing, which is favorable for most of the interfaced parts of mechanisms and machines. A comparison of the depth of the stressed and hardened layer, the stress gradient and the hardening gradient shows that the depth of the stressed layer is 1.1 ... 1.3 times greater than the depth of the riveted layer, which is consistent with the theory of surface plastic deformation.

The ultimate roughness value achieved during processing by the proposed method is Ra = 0.08 μm, a reduction of the initial roughness by a factor of 5 is possible.

Impulse-impact deformation in the process favorably affects the working conditions of the tool. It leads to a more uniform distribution of the load on the deforming elements, facilitates the formation of a hardened surface.

Impulse-impact deformation contributes to better penetration of cutting fluid (coolant) into the treatment area. When applying a pulsed load, the deforming elements and the deforming surface periodically “rest”, which helps to increase its resistance. Processing under conditions of pulse-impact deformation sharply increases the cooling, dispersing and plasticizing effect of the coolant due to the facilitation of its access to the contact zone of the deforming elements and the workpiece.

The proposed method extends the technological capabilities of pulse-impact treatment by surface plastic deformation, allows you to control the depth of the hardened layer, the degree of hardening and the surface microrelief. At the same time, a structurally simple drive reduces the cost of processing, increases productivity, improves the quality of the machined surface, does not require complex and lengthy settings.

The movable connection and the installation of deforming elements on leaf springs centers the blank as a rest, which makes it possible to increase the accuracy of machining of non-rigid blanks and to exclude the influence of beating of the surface of the blanks acquired in previous operations.

Information sources

1. Reference technologist-machine builder. In 2 vols. T 2 / Ed. A.G. Kosilova and R.K. Meshcheryakova. - 4th ed., Revised. and add. - M.: Engineering, 1985. S.386-388, Fig. 7 - prototype.

2. RF patent 2276005, IPC B24B 39/04. The method of running in incomplete spherical surfaces. Stepanov Yu.S., Kirichek A.V., Samoilov N.N., Gavrilin A.M., Afanasyev B.I., Katunin A.A., Fomin D.S. 2004129399/02; 10/05/2004; 05/10/2006. Bull. No. 13.

3. RF patent 2276006, IPC B24B 39/04. Device for pulse-impact deformation of spherical surfaces. Stepanov Yu.S., Kirichek A.V., Samoilov N.N., Afanasyev B.I., Katunin A.A., Katunin A.V. Fomin D.S. 2004136428/02; 12/14/2004; 05/10/2006. Bull. No. 13.

Claims (1)

The method of pulse-shock hardening by surface plastic deformation of parts in the form of shafts with complex profiles, comprising communicating to the workpiece and a multi-element rolling deformation tool of rotational movements around its own axes and longitudinal feeding the multi-element rolling deformation tool, characterized in that they use a multi-element rolling deformation tool containing a central hole made in the form of a stator of a three-phase asynchronous short circuit a closed-circuit electric motor, inside of which a rotor in the form of a hollow shaft with spline grooves on the surface of its hole is mounted on rolling bearings, a copier in the form of a disk with a central hole, rigidly fixed to the end of the housing, and V-shaped curved flat plate springs made of steel tape, installed in the rotor hole, one end of which is rigidly fixed to the end of the rotor, the other end is located in the central hole of the copier and it is affected by the surface of the said hole the protrusion and valleys are fixed in their middle part, deforming elements are fixed, while deforming elements cover the workpiece, and the inner diameter passing through their vertices when the leaf springs are in the free state is less than the diameter of the shaft workpiece by the amount of interference created by the plate springs and providing the force of surface plastic deformation.

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