RU2420390C2 - Method of burnishing by electric head - 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. Billet and 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. Deforming elements are arranged inside the rotor, in its bore, and on one end of L-bent plate springs. Plate springs have their other end rigidly secured onto rotor end face. Deforming elements make external elements of the workpiece.

EFFECT: expanded performances, higher efficiency and quality.

5 dwg

Description

The invention relates to the processing of metals by pressure, in particular to the treatment of surface plastic deformation (PPD), and can be used for finishing and hardening the rolling of non-rigid shafts with screw, cylindrical and other complex profile surfaces, for example screw pump pumps, screw surfaces with rounded sinusoidal profile, eccentric shaft necks, cam surfaces and PK profiles.

There is a method of rolling in 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, while the holder allows you to unload the machine components from unilaterally applied efforts and processing non-rigid parts such as shafts [1]. The hinged connection of the holder with the body increases the accuracy of the shaft processing and eliminates the influence of the beating of the shaft surface acquired in previous operations.

The disadvantages of the known method and device are the narrow technological capabilities in which the finishing by surface plastic deformation (PPD) of the screw outer surfaces after appropriate modernization is very difficult, and in some cases impossible, while low productivity and complicated long-term adjustment increases 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-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 ring body by the amount of eccentricity [2, 3].

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

The objective of the invention is to expand the technological capabilities of PPD of complex-profile surfaces by using a covering tool with deforming elements located on the inner surface located in the rotor of the electric motor and allowing to improve the quality of the processed surface, increase productivity and reduce the cost of processing.

The problem is solved by the proposed method of rolling surface plastic deformation of preforms of non-rigid shafts with complex profile surfaces, including communicating to the preform and multi-element deforming tool rotational movements around its own axes and longitudinal feed to the deforming tool, using a multi-element deforming tool containing a housing with a central hole made in the form of a stator three-phase asynchronous squirrel-cage electric motor a body, inside which a rotor in the form of a hollow shaft is mounted on rolling bearings, in the hole of which there are deforming elements installed on one end of the L-shaped curved leaf springs from steel cold-rolled heat-treated tape, which are rigidly fixed to the end of the rotor at the other end, while the deforming elements cover the workpiece, and the inner diameter passing through their vertices when the leaf springs are in a free state is less than the diameter of the shaft workpiece by the amount of interference that creates th via leaf springs and provides a force of surface plastic deformation.

Features of the method and design of the device that implements the proposed method are illustrated by drawings.

Figure 1 shows a diagram of the implementation of the proposed method of rolling in a screw complex profile surface of a non-rigid screw electric head, a longitudinal section; figure 2 is a view along A in figure 1, an end view; figure 3 is a General view of the electric side view; figure 4 is a diagram for determining the magnitude of the interference fit, a deforming tool in a free, unloaded state; figure 5 is a diagram of the run-in of the protrusion of the helical surface of the workpiece of the screw and the cavity (thin line) due to the radial S _p movement of the deforming element mounted on the L-shaped plate spring.

The proposed method and device are designed for PPD rolling in non-rigid shafts with screw, cylindrical and other complex profile surfaces (for example, screw pump screws, screw surfaces with a rounded sinusoidal profile, cylindrical shafts, cam shafts, cam surfaces and PK profiles). Operation of the method lies in the fact that in the workpiece deforming tool 1 and 2 report the rotational motion V _{and W} and V, respectively, wherein the apparatus with a deforming tool longitudinal feed motion report S _PR. The device has deforming elements, which with a certain force plastically deform and strengthen the outer surface.

For PPD, by rolling around the workpiece surface, for example, a screw of a screw pump 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 the center of the tailstock pressed (not shown), and rotational movement is reported V _W around its central axis, and deforming tool device 2 - a longitudinal feed S _PR and the possibility to make deforming elements reciprocating radial movements S _p in the transverse direction causes s recesses and protrusions preform.

The method is implemented by a device consisting 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 bore of the rotor 6, leaf springs 7 are installed and at one end are rigidly fixed to the end of the rotor. The leaf springs are L-shaped and bent, for example, made of cold-rolled steel heat-treated tape, for example, according to GOST 21996-76. At the other end of the L-shaped curved leaf spring 7 is installed a deforming element, for example a ball 8.

The number of deforming elements 8 is determined from design considerations so that they cover the shaft preform 1 and the inner diameter d along the vertices of the deforming elements mounted on leaf springs that are in a free state, less than the machined diameter of the shaft preform D _{1 by the} tightness “n”. The interference "n" affects the force of rolling in and hardening P, created by the elastic properties of leaf springs, the greater the interference, the greater the force of rolling in and hardening R. Adjustment of the force of rolling in and hardening P is made by changing the value of interference "n".

Forced reciprocal radial displacements S _p made by deforming elements in the transverse direction are provided by the bending of leaf springs 7.

When readjusting and switching to processing another workpiece, a change in the rolling and hardening forces P acting by deforming elements on the workpiece surface 1 requires replacement of leaf springs.

The proposed device design and mounting on leaf springs 7 deforming elements 8, which cover the workpiece over the entire diameter, allows you to balance the impact of the strengthening force P and get rid of the longitudinal deflection of the processed non-rigid workpieces, and does not require the use of a backrest.

The rotational movement V _{And the} rotor shaft 6 with deforming elements 8 is transmitted using electric forces induced in the stator case of the electric motor, and is the minimum kinematic chain in length and complexity, and eliminates the use of intermediate belt, gear and other gears and reducers, therefore the device differs in minimum energy losses and has high efficiency.

The rolling is carried out by rollers or balls, which exert pressure P on the surface of the workpiece. With a certain working force in the contact zone between the deforming elements and the workpiece, the stress intensity exceeds the yield strength, resulting in plastic deformation of microroughnesses, the physicomechanical properties and structure of the surface layer change, namely, microhardness increases and residual stresses arise in the surface layer. Volumetric deformation of the workpiece is negligible.

The hardness of the surface layer and surface roughness obtained by the proposed method depend on the hardening force P. These parameters, in turn, depend on the peripheral speed of the rotor shaft with deforming elements, the interference fit, the size of the deforming elements, their number, rotation frequency, and the longitudinal feed of the device and the number of passes.

The RPM modes of rolling in the proposed method, implemented by a device equipped, for example, with balls with a diameter of 5 ... 10 mm, of steel billets are as follows: peripheral speed of the rotor shaft - V _And ≈1.0 ... 2.0 m / s, peripheral speed of the workpiece - V _З ≈ 0.5 ... 1.5 m / s, the number of passes - 2 ... 3, interference - n≈0.5 ... 1.5 mm.

As a result of 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 Ra = 0.8 ... 3.2 μm. The hardness of the treated surface increases by 25 ... 75%. The residual compressive stresses reach 350 ... 550 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 of rolling-in PPD allows you to create a regular microrelief on the machined complex-profile, including screw surface, able to hold lubricants and extend the life of parts during operation.

The PPD method 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 and device processed installed in the cartridge with an electromechanical drive on a lathe mod. 16K20F3 screw blank for the left Н41.1016.01.001 screw pump EVN5-25-1500, 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. Processing was carried out using the developed device, based on the IM5010 electric motor, model 4АВ132В6, having a rotor shaft rotational speed of 1000 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; stator housing length - 253 mm; the outer diameter of the stator housing is 261 mm.

RPMs were run in the following modes: peripheral tool speed - V _AND ≈1.5 m / s; the peripheral speed of the workpiece is V _З ≈1.0 m / s, the number of passes is 3, the interference is 1.2 mm, the longitudinal S _PR is 1.5 ... 2.0 mm / rev, the hardening force is 170 ... 175 N; the screw diameter changed after processing by 0.02 mm (0.01 mm per side); the depth of the hardened 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 initial roughness parameter Ra = 3.2 μm, achieved - Ra = 0.32 μm; deforming tool - balls with a diameter of 7 mm from steel ШХ15, hardness HRC 63 ... 65.

The depth of the hardened layer is 1.5 ... 2 times higher than with traditional rolling.

мин по базовому варианту при традиционном обкатывании винтов на токарном станке 1К62 на ОАО "Ливгидромаш").The required roughness and accuracy of the helical surface was achieved after T _m = 3.6 min (against

min according to the basic version with the traditional rolling of screws on a 1K62 lathe at Livhydromash OJSC).

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 0.15 ... 0.20 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 ICh10B class. 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 showed that the maximum residual stresses are close to the surface, as when chasing, which is favorable for most of the mating parts of mechanisms and machines.

The maximum roughness value achieved during processing by the proposed method and device is Ra = 0.08 μm, a possible initial roughness reduction of 4 times is possible.

Running in and deformation of the proposed method using a reinforcing electric head favorably affects the working conditions of the deforming tool of the device. It leads to a more uniform distribution of the load on the deforming elements, facilitates the formation of a hardened surface.

The application of the proposed method and device contributes to better penetration of the cutting fluid (coolant) into the treatment area. The application of the proposed method, implemented by a multi-element deforming tool, helps to increase the durability of each deforming element that works separately. Processing under the conditions of the proposed deformation dramatically increases the efficiency of the cooling, dispersing and plasticizing action of the coolant due to the facilitation of its access to the contact zone of the deforming elements and the workpiece.

The proposed method and device expand the technological capabilities of processing PPD, allow you to control the depth of the hardened layer, the degree of hardening and the surface microrelief. At the same time, the structurally simple and compact drive of the device reduces the cost of processing, increases productivity, improves the quality of the processed surface, does not require complex and lengthy settings.

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 V24V 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 V24V 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)

A method for rolling surface plastic deformation of preforms of non-rigid shafts with complex profile surfaces, including communicating to the preform and multi-element deforming tool rotational movements around its own axes and supplying a deforming tool longitudinally, characterized in that they use a multi-element deforming tool containing a housing with a central hole, made in the form stator of a three-phase asynchronous squirrel-cage motor, inside of which on a bearing The rolling rotors are mounted in the form of a hollow shaft, in the hole of which there are deforming elements installed on one end of the L-shaped curved leaf springs made of cold-rolled steel heat-treated tape, which are rigidly fixed to the end of the rotor at the other end, while the deforming elements cover the workpiece, and the inner the diameter passing through their vertices when the leaf springs are in a free state is less than the diameter of the shaft blank by the amount of interference created by the leaf springs n and provides a force of surface plastic deformation.

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