RU2420391C2 - Method of surface plastic deformation of complex-shape surfaces by electric hardening 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 used that comprises body made up of three-phase induction squirrel-cage motor with rotor running in antifriction bearing there inside. Rotor bore surface is provided with race for deforming elements to be arranged thereon. Body is pivoted on aforesaid support to perform reciprocating oscillations there across. Compression spring secured on the support is used to preset surface plastic deformation.

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 the processing of impulse-impact surface plastic deformation (PPD), and can be used for finishing and hardening of cylindrical, screw and complex surfaces, for example, screw pump pumps, screw surfaces with a rounded sinusoidal profile , eccentric necks of shafts, cam surfaces and PK profiles.

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 [1, 2].

The disadvantages of the known method and device are the narrow technological capabilities in which the finishing by 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 of complex surfaces by using a covering tool in the form of a ring with deforming elements - balls located on the inner surface, oscillating in the transverse plane, located in the rotor of the electric motor and allowing to improve the quality of the processed surface, increase productivity and reduce costs processing.

The problem is solved by the proposed method of hardening by surface plastic deformation of parts such as shafts with complex profiles, including communicating to the workpiece and the deforming tool in the form of a multi-element rolling tool of rotational movements around its own axes and longitudinal feed to the deforming tool, using a deforming tool containing a case with an individual drive and a central hole made in the form of a three-phase asynchronous stator to a short-circuited electric motor, inside of which a rotor in the form of a hollow shaft is mounted on rolling bearings, on the surface of the hole of which a track is made on which deforming elements are located, while providing a reciprocating transverse movement of the housing, which is pivotally mounted on the bracket and set the surface plastic deformation by a spring compression mounted on the bracket.

Features of the method are illustrated by drawings.

Figure 1 shows a diagram of the hardening of a screw complex profile surface, a longitudinal section of a device that implements the proposed method; figure 2 is a view along A in figure 1, an end view; figure 3 is a General side view of figure 1; figure 4 is a diagram of the strengthening of the depression and protrusion of the workpiece screw.

The proposed method is implemented by a device designed for plastic deformation of screw and complex surfaces (for example, screw pumps, screw surfaces with a rounded sinusoidal profile, cylindrical shafts, eccentric journals of shafts, cam surfaces and PK profiles), the work of which is that the workpiece and the deforming tool report rotational movements V _W and V _And, respectively, while the device with the deforming tool report the movement longitudinal feed S _PR . The device has deforming elements that inflict numerous blows on the surface of the workpiece, plastically deforming and hardening the outer surface.

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 the rotational motion V _W around its central axis, the shock pulse-deforming tool device 2 - a longitudinal feed S _PR and the possibility to make reciprocating oscillatory motion in S _QTY operechnom direction.

A device that implements the method 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 hole of the rotor 6 there is a track 7 with deforming elements 8 located therein, for example balls.

The stator housing 3 is pivotally mounted on the bracket 9 with the possibility of reciprocating motion S _KOL in the transverse direction. The hinge 10 consists of a loop 11 fixed to the stator housing and a loop 12 belonging to the bracket 9 connected by an axis 13. The axis 13 of the hinge 10 is mounted parallel to the central longitudinal axis of the workpiece 1.

The hardening force P acting through the deforming elements - balls 8 on the workpiece surface 1 is defined by a compression spring 14 mounted on the bracket 9. The hardening force P is adjusted by a threaded plug 15 screwed into the threaded hole in the bracket 9, where the spring 14 is installed.

The proposed design of the device and the fastening of the deforming tool 3 in the bore of the rotor 6 of the electric motor mounted, for example, on the transverse support of a lathe (not shown) allows the housing 3 to make forced oscillatory movements S _KOL , caused by the eccentric displacement and location of some sections of the machined helical surface. The amplitude A vibrational motion _{to the} housing is A = _{K 1} 2e where e ₁ - eccentricity slozhnofasonnoy surface (e.g., the eccentricity of the left screw N41.1016.01.001 screw pump EVN5-25-1500 equal to e ₁ = 1.65 mm, see Fig. .1; 3; 4).

The transition of the contact of the tool with the workpiece 1 from one deforming element 8 to two deforming elements causes a pulse-impact plastic deformation of the surface layer of the workpiece.

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 minimal in length and complexity and eliminates the use of intermediate belt, gear and other gears and reducers, therefore the device has a high efficiency .

In order to create a force P for surface plastic deformation, a compression spring 14 is installed that exerts pressure P on the housing 3 and, accordingly, on the deforming elements 8 in the transverse direction. The movable fastening of the deforming elements 8 in the track 7 is carried out by known methods, for example, using a cover that is bolted to the end of the rotor shaft.

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

The modes of pulse-impact deformation for the proposed method and device equipped, for example, with balls with a diameter of 5 ... 10 mm and steel billets are as follows: the peripheral speed of the rotor shaft is V _And ≈20 ... 40 m / s, the peripheral speed of the workpiece is V _З ≈0, 05 ... 0.5 m / s, the number of passes - 2 ... 3, the interference - 0.1 ... 0.25 mm.

As a result of pulse-impact plastic deformation of microroughnesses and the surface layer of the proposed method and device, 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% 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 of pulse-impact deformation allows you to create a regular microrelief on the complex surface, including a screw surface, that can hold lubricants and extend the life of parts during operation.

The method of 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 and device installed in the cartridge with an electromechanical drive lathe mod. 16K20F3, we processed the 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, screw cross-section diameter - ⌀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 4АВ132 В6, having a rotor shaft speed of n = 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.

Impulse-impact PPD were conducted in the following modes: peripheral speed of the instrument - V _And ≈15 m / s; the peripheral speed of the workpiece is V _З ≈0.05 m / s, the number of passes is 3, the interference fit is 0.2 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 0.02 mm (0.01 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 ШХ15, hardness HRC 63 ... 65, located in the inner track, inner radius at the tops of the deforming elements R _K = 40.57 mm.

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 helical surface was achieved after T _m = 3.6 min (against T _m ^bases = 10.5 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 0.15 ... 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 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 maximum roughness value achieved during processing by the proposed method is R _a = 0.08 μm, a reduction of the initial roughness by a factor of 6 is possible.

Impulse-impact deformation in the process favorably affects the operating conditions of the device. 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 the 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.

Information sources

1. 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.

2. 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 is a prototype.

Claims (1)

The method of hardening by surface plastic deformation of parts such as shafts with complex profiles, comprising communicating to the workpiece and the deforming tool in the form of a multi-element rolling tool of rotational movements around its own axes and longitudinal feed to the deforming tool, characterized in that they use a deforming tool containing a case with an individual drive and a central hole made in the form of a stator three-phase asynchronous squirrel-cage motor For the inside of which a rotor in the form of a hollow shaft is mounted on rolling bearings, on the surface of the hole of which a track is made on which deforming elements are located, they provide a reciprocating vibrational movement of the housing, which is pivotally mounted on the bracket and sets the surface plastic deformation force by the compression spring attached to the bracket.

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