RU2319596C1 - Apparatus for static-pulse strengthening of complex-profile parts - Google Patents

Abstract

FIELD: manufacturing processes in machine engineering, namely apparatuses for static-pulse strengthening of complex-profile parts.

SUBSTANCE: apparatus includes striker, first and second hydraulic cylinders, wave-guide and chamber filled with deforming members in the form of micro-balls or balls and made with possibility of placing blank inside it. Two shoes having concave cylindrical surfaces are arranged in said chamber. First hydraulic cylinder is connected to hydraulic pulse generator for providing pulse load of deforming members. Second hydraulic cylinder is made with possibility of acting upon first hydraulic cylinder for providing static load of deforming members. The last are arranged between concave cylindrical surfaces of shoes and blank with possibility of embracing blank. One shoe is made with possibility of motion and it is jointly coupled with wave-guide. Said chamber has through openings in its two mutually opposite walls in order to form path for passing blank and it has locks with shock absorbers. Wave-guide and striker are arranged in first hydraulic cylinder.

EFFECT: enlarged manufacturing possibilities, improved efficiency, quality and accuracy of working.

2 dwg, 1 ex

Description

The invention relates to mechanical engineering technology, in particular to devices and methods for finishing and hardening processing of complex profiles of steel and alloy parts by surface plastic deformation (PPD) with static-pulse loading of a multi-element deforming tool.

A known method and device for hardening the surfaces of parts of complex shape with microspheres and balls in an ultrasonic field using a magnetostrictive transducer, rigidly bonded to a conical hub, which in turn is connected to a hollow waveguide [1]. The balls and the workpiece are placed in a hollow waveguide, which is a chamber.

The disadvantages of the known method and device are the limited size of the hardened blanks, only for small blanks with a length of not more than 400 mm and a transverse dimension of 160 ... 200 mm. The oscillation intensity decreases sharply with large dimensions of the workpiece. In order for the waveguide oscillation amplitude to be sufficient for the formation of the required level of residual stresses in the hardened workpieces, strict requirements are placed on ultrasonic generators, which necessitate the operation of them at maximum permissible modes, and this is undesirable, since it worsens their work, leads to a mismatch in the resonant frequency and ultimately the result is a violation of the hardening process. In addition, in the bottom part of the hollow waveguide there is a "dead" zone, which limits the dimensions of the hardened workpiece. The device is characterized by low efficiency, high energy intensity, insufficiently large depth of the hardened layer and a low degree of hardening of the treated surface.

The objective of the invention is to expand the technological capabilities of PPD through the use of static-pulse loading of a multi-element deforming tool that allows you to control the depth of the hardened layer, the degree of hardening and the surface microrelief, as well as improving productivity, quality and accuracy of processing thanks to the tool covering and self-aligning on the workpiece.

The problem is solved using the proposed device for static-pulse hardening of complex parts containing a chamber that is filled with deforming elements in the form of beads or balls and is configured to accommodate a workpiece, and a waveguide, while it is equipped with two pads concave in the chamber cylindrical surfaces, brisk, the first hydraulic cylinder connected to a hydraulic pulse generator to create a pulse load on the deforming elements and the second hydraulic cylinder, made with the possibility of acting on the first hydraulic cylinder to create a static load on the deforming elements, the latter are located between the cylindrical concave surfaces of the blocks and the workpiece with the possibility of gripping the latter, one of the said blocks is movable and pivotally connected to the waveguide, the camera is made through holes in its two opposite machines to ensure the passage of the workpiece and contains gates with shock absorbers, located data in said through-holes of the chamber, wherein the waveguide and the striker are made of the same diameter and are located in the first hydraulic cylinder.

The essence of the device is illustrated by drawings.

Figure 1 presents a diagram of hardening treatment by surface plastic deformation of a screw workpiece of a screw oil pump using the proposed device with static-pulse loading of a multi-element deforming tool in the form of balls, a longitudinal section, the device is in position at the time of changing the workpiece; figure 2 is a cross section aa in figure 1, the device is in the working position.

The proposed device is used for surface plastic deformation of complex parts 1 using constant static P _article and periodic impulse P load _them on a multi-element deforming tool 2, in which the workpiece, for example, a screw of a screw oil pump, is given a rotational movement V _s and an additional reciprocating longitudinal motion S _pr device.

The device consists of a robust box-shaped chamber 3, assembled, for example, from separate rectangular steel plates. The chamber 3 has through holes 4 in two opposite walls 5 for passing the workpiece 1. The holes 4 are made of a slightly larger diameter than the workpiece, allowing free passage and rotation of the workpiece 1, partially located in the chamber 3. The entire internal space in the chamber 3 in addition to the workpiece 1 occupy two blocks 6, 7 and deforming elements in the form of beads or balls 8. The upper (according to Fig.1-2) block 6 is stationary, the other, lower, block 7 is movable and pivotally connected to the waveguide 9. Surfaces ca. 6 and 7 are shaped flat chamber 3 in which they are located, except for the surfaces 10 facing the workpiece. For this design of the workpiece of the screw, these are concave cylindrical surfaces 10 covering the workpiece. Between the cylindrical concave surfaces 10 of the blocks 6 and 7 and the workpiece 1 are deforming elements in the form of beads or balls 8, which cover the workpiece and have a reinforcing effect when moving the movable block 7 upward under the action of forces P _article and P _them , as well as their combined action . Under the action of the forces P _st and P _them balls equally affect both the workpiece and the walls of the chamber and pads. Therefore, on the side walls 5 of the chamber, which are made double, the valves 11 are installed in the form of rings, centered by the shock absorbers 12. The valves are made in the form of rings with an opening for the passage of the workpiece and perform a planetary motion in contact with the complex surface of the workpiece.

The number of balls 8 in the chamber 3 is such that when creating the necessary load P _{t, the} space between the blocks 6, 7 and the workpiece 1 is completely filled and a guaranteed clearance Z remains between the blocks.

The waveguide 9, pivotally using two half rings 13 and screws 14 connected to the movable block 7, is located with its lower part in the hydraulic cylinder 15 together with the striker 16 and has the same diameter with it. The hydraulic cylinder 15 is connected to a hydraulic pulse generator (GGI) (not shown) [2-4] to create a pulse load P _them on the deforming balls 8. The static load P _article on the balls 8 is provided by the second hydraulic cylinder 17 acting through the piston 18 and the rod 19 on the first hydraulic cylinder 15. The waveguide 9 and the firing pin 16 are made in the form of rods of the same diameter and are located in the housing of the hydraulic cylinder 15, which is connected to the GGI, which generates and creates a pulsed load.

Static loading P _{st is} carried out by means of a hydraulic cylinder 17, which through a hydraulic cylinder 15, a waveguide 9 and a movable block 7 constantly acts on a deforming tool - balls when they come in contact with a complex surface of the workpiece. The value of the static deformation force is selected as the largest of those providing elastic contact deformations of the processed material.

Impulse loading P by _{him is} carried out by hitting the striker 16 at the end of the waveguide 9, on which a movable block is mounted, which transfers pressure to the instrument 2. As a result of the shock, shock and oppositely directed pulses of the same amplitude and duration arise in the striker and waveguide, each of which will affect the processed surface with a cycle equal to double pulse duration. Having reached the surface to be treated, the shock pulse is distributed on the passing and reflecting. The passing pulse forms the dynamic component of the strain force.

Impact impulse introduces deforming elements - balls - into the surface to be machined by a larger amount than with traditional processing using only static load.

The depth of the hardened layer obtained using the proposed device reaches 1.5 ... 2.5 mm, which is significantly (3 ... 4 times) more than with traditional static hardening. The greatest degree of hardening is 15 ... 30%. As a result of static-pulse processing using the proposed device compared to traditional hardening, the effective depth of the layer, hardened by 20% or more, increases by 1.8 ... 2.7 times, and the depth of the layer hardened by 10% or more, - 1.7 ... 2.2 times.

Features of processing blanks using the proposed device are as follows. The device is installed, for example, on a support of a lathe so that the axis of the holes 4 in the walls 5 of the housing 3 are at the level of the axis of the centers of the machine. The support with the device is moved to the front headstock and installed at a distance of up to 5 mm relative to the cams of the turning chuck. The waveguide 9 and the lower block 10 are in the lowermost loading position, with the balls rolling down and their upper level below the edge of the hole 4. The workpiece, for example, a screw, is passed through the holes in the shutters 11, fasten it in the cams of the cartridge and tighten the center of the tailstock. In order to process the workpiece along the entire length, technological sleeves, elongated centers and other technological equipment are used. The hydraulic _station is turned on and the hydraulic cylinder 17, which lifts the waveguide 9 and the block 10 with balls 8, which cover the part of the workpiece 1, comes into operation. The necessary load P _{st is created} , the rotational movement of the workpiece V _s and the longitudinal feed S _{pr of the} caliper are turned on.

The balls are lubricated periodically through holes in the absence of a workpiece. The surface of the workpiece is also lubricated before hardening, which eliminates undesirable dry friction in the area of contact of the balls with the hardened surface.

In a closed volume, balls fill the entire space around the workpiece and roll when the latter rotates.

A periodic impulse load P _is carried out using a striker 16, acting on the end of the waveguide 9, which is pivotally connected to the movable block 7. As a result of the strike of the striker 16 at the end of the waveguide 9, shock and oppositely directed pulses of the same amplitude and duration arise in each of which it will act through a movable block and balls on the surface to be treated with a cycle equal to twice the duration of the pulses. Having reached the surface to be treated, the shock pulse is distributed on the passing and reflecting. The transmitted pulse forms a dynamic component of the deformation force, which intensifies the process of surface plastic deformation and strengthens the surface layer of the processed complex shaped surface. The ability to rationally use the energy of shock waves is determined by the size of the instrument.

Example. To assess the quality parameters of the surface layer hardened by the proposed method, experimental studies of the treatment of the screw of the left H41.1016.01.001 screw pump EVN5-25-1500 were carried out, which had the following dimensions: total length - 1282 mm, length of the screw part - 1208 mm, diameter the screw cross section is ⌀27 ^-0.05 mm, the eccentricity is 3.3 mm, the pitch is 28 ^{± 0.01} mm, the roughness R _a = 0.4 μm; single-helical screw surface, left direction; material - steel 18HGT GOST 4543-74, hardness HB 207-228, weight - 5.8 kg. Processing was carried out on a mod screw-cutting machine. 16K20 using the proposed device and stand with a hydraulic pulse generator [2-4]. The values of technological factors (frequency of impacts, radius of the tool ball, value of circular feed) 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 value of the force of static preloading of the tool to the work surface was P _article ≥25 ... 40 kN; P _them = 255 ... 400 kN. The depth of the hardened layer by static-pulse processing is 3 ... 4 times higher than with traditional hardening. The hardened layer during traditional static processing is formed under long-term action of large static forces.

In the proposed device, a similar depth of the hardened layer is achieved as a result of a short-term impact on the deformation zone of a prolonged energy pulse. At close degrees of hardening of the surface layer, the magnitude of the static component of the load in the proposed static-pulse processing is much less.

Studies of the stress state of the hardened surface layer by static-pulse treatment 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.

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 device is R _a = 0.08 μm, a reduction of the initial roughness by a factor of 6 is possible.

Impulse loads created by the proposed device, favorably affect the working conditions of the tool. The imposition of oscillatory motion leads to a more uniform distribution of the load on the deforming elements of the tool, causes additional cyclic movements of the contact surfaces of the tool and the workpiece, facilitates the formation of a hardened surface. Impulse loads contribute to better penetration of the lubricant into the treatment area. When vibration is applied, the deforming surface of the tool periodically “rests”, which helps to increase its resistance.

Processing under pulsed loads dramatically increases the efficiency of the cooling, dispersing and plasticizing action of the lubricant due to the facilitation of its access to the contact zone between the tool and the workpiece.

The proposed device extends the technological capabilities of PPD through the use of static-pulse loading on a deforming tool, allows you to control the depth of the hardened layer, the degree of hardening and surface microrelief, and also improves the quality and accuracy of processing the workpiece.

Sources of information taken into account:

1. Malygin B.V. Magnetic hardening of tools and machine parts. - M.: Mechanical Engineering, 1989. P.168 ... 174, Fig. 4.12, a.

2. RF patent 2098259, MKI ⁶ V24V 39/00. Lazutkin A.G., Kirichek A.V., Soloviev D.L. The method of static-pulse treatment by surface plastic deformation. No. 96110476/02, 05.23.96; 12/10/97. Bull. Number 34.

3. Kirichek A.V., Lazutkin A.G., Soloviev D.L. Static-pulse processing and equipment for its implementation // STIN, 1999, No. 6. - S.20-24.

4. RF patent 2090342. Lazutkin A.G., Kirichek A.V., Soloviev D.L. Water hammer device for processing parts by surface plastic deformation. 1997. Bull. Number 34.

Claims (1)

A device for static-pulse hardening of complex-profile parts, containing a chamber that is filled with deforming elements in the form of microspheres or balls and is configured to place a workpiece in it, and a waveguide, characterized in that it is equipped with two pads in the chamber with concave cylindrical surfaces, a striker , the first hydraulic cylinder connected to the hydraulic pulse generator to create a pulse load on the deforming elements, and the second hydraulic cylinder, made with In order to create a static load on the deforming elements, the latter are located between the cylindrical concave surfaces of the blocks and the workpiece with the possibility of covering the latter, one of the said blocks is movable and pivotally connected to the waveguide, the camera is made with through holes in its two opposite the walls to ensure the passage of the workpiece and contains gates with shock absorbers located in the aforementioned through holes of the cam ery, while the waveguide and the firing pin are made of the same diameter and are located in the first hydraulic cylinder.

Images