CS215622B1 - Method of and apparatus for reinforcing machinery elements provided with projections - Google Patents

Abstract

The invention relates to a method of strengthening machine parts with protrusions, working in particular, the variable direction of the service load, which rests in plastic overlays bending and bending material measurements of the protrusion surface layer in the area of its dangerous cross section bending force. Bending force processing the surface of the protrusion in its lining The dangerous cross section is carried out according to at the same time, while the hardening treatment surface of the protrusion in its hazardous area Its cross section is done by getting to the surface the contours of the dangerous cross section of the projection are the amounts act by a normal compressive force, divided along this surface. The invention also relates to apparatus for reinforcing components with protrusions, in particular, gears including the press rollers having a tooth shape in the cross section and / caused for carrying out the method according to the invention lezu.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a technology for strengthening machine parts by varying their state of stress and the physical properties of the metal from which they are made by plastic deformation thereof, and more particularly to a method for strengthening machine parts with projections and devices for performing the method.

Preferably, the present invention is suitable for strengthening such machine parts with projections that operate in a variable direction of operation, for example, gear teeth, turbine blades, and the like.

At present, methods for increasing the strength of machine parts utilizing the plastic deformation of a part during reinforcement do not throw wide application. In these cases, plastic deformation is used to change the physical properties of the metal, in particular the breaking strength, yield strength, hardness, macro and microstructure, as well as the inherent stress.

It is known that the plastic deformation of a metal capable of increasing the strength results in an increase in its strength, yield strength and hardness compared to the initial values.

In addition, if a component profile is in a non-uniform state of stress during the plsstic or elastic-plsstic deformation, residual stresses arise in this cross-section after the load has been abolished, which is due to the severely variable deformation degree of the individual sections.

Known techniques for strengthening metal components that utilize the above physical phenomena to plasticly deform the surface of the components are referred to as plastic surface deformation (PPP). The PPP procedure is particularly well suited for components with stress-collecting areas and for components with loaded lugs operating under variable load conditions. First of all, this method, as is known, applies to such parts with protrusions such as gears, turbine blades and crankshafts. This plastic deformation is carried out by blasting the treated surface of the projections with the balls or by oval-rolling it with the rollers, or also by pushing the diamond tool flat.

In one known method, this strengthening applied to the gears is carried out by plastic deformation of the tooth profile by rolling the aa profile of the tooth projections with toothed rollers. In this case, the plastic deformation of the metal is sucked in by a temporary radial displacement of the toothed rollers which are applied and with a certain tightening corresponding to the required degree of hardening. The rollers plastically deform the metal of the toothed profile of the reinforced gear by performing a plastic deformation of its surface, which leads to an increase in the strength values of the component.

For example, the reinforcement by plastic deformation of the surface is carried out by means of a device according to Soviet copyright certificate 158 911, consisting of a driving mechanism e of a stand having a mechanism for producing plastic deformation and a device for fastening the reinforced component. gear and working rollers of said mechanism.

In the known process, the reinforcement of the metal is divided into a limited depth which, for example, does not exceed 3 mm for the teeth of the module 10-11 mm. This leads to the fact that the deposition depth of the residual compressive stress at module m = 10 mm does not exceed 0.7 mm and therefore has a relatively insignificant effect on the stress distributed in the components during operation. So it is plastically transformed ·

215 622 or only a thin surface layer of the projections of the reinforced component, and attempts to increase the depth of the reinforced layer by increasing the pulling of the toothed roller do not produce the desired result, since excessive reinforcement of the material on the surface leads to peeling.

It should be noted that the depth and nature of the residual compressive stress distribution considerably affect the ability of machine parts with projections to transmit loads and their strength. However, the known plastic surface deformation processes do not allow the residual stress distribution to be achieved in which the resulting stresses in the projection material of the respective component are sufficiently evenly distributed over the entire dangerous cross-section of the projection, under the effect of the operational load.

The nature of the residual stress distribution, using known plastic surface deformation techniques, results in the maximum stress resulting from the effects of the in-service load being deposited in the surface layer of the material, while the core material insignificantly involved in the in-service .

Furthermore, methods of solidification are known which employ spatial solidification of machine parts with cold projections. In one known method of this kind, described in U.S. Patent No. 3,851,512, this strengthening is achieved by plastic bending of the teeth in the direction of the main service load. By bending the teeth of the reinforced gear, which causes stress in the tooth material above the yield strength with the same sign as · the stresses caused by the service load, residual stresses are created in the dangerous tooth cross-section which have a significant effect on the redistribution of the stresses caused by the service load; provide a more energy-efficient state of the tooth material including the core material during the operation of the gears.

Plastic bending allows the cold cure of a large part of the dangerous cross-section, which is not acceptable for reinforcement methods that use plastic surface deformation.

The bending of the gear teeth by plastic bending in the direction of the main service load is carried out by means of a device comprising a stand on which the plastic generating mechanism is mounted, a gear-fastening device and a driving device for relative relative displacement of the gear mechanism e. The plastic deformation mechanism is formed in the form of a ring with internal projections which, during relative displacements of the ring and the gear mounted internally on the fastening device and coaxially arranged, interact with the teeth of that wheel along their length by bending them In the case of the tooth material, the stresses above the yield stress with the same sign as the service load have. As a result, the dangerous cross-section is spatially reshaped.

The disadvantage of this method is that residual tensile stresses occur on the teeth side facing the technological load approach. This limits the field of application of the method to such gears whose teeth are loaded predominantly in one direction. In addition, the consumption of the potential energy of the tooth core for expanding the web, pushed forward, reduces the absolute magnitude of the residual spikes remaining on the work side of the tooth, thereby reducing the reinforcement effect. The method is also poorly effective in the case of static traffic load, which limits its application to those components that operate under cyclic load.

It is also known to process components to increase the strength of gears

There is also known a method of processing components which allows to increase the bending strength of the gears, which take over the load in an arbitrarily variable direction from operation. The method consists in subjecting the teeth of the gear wheels to a pleated deformation in bending and then subjecting them to a heat treatment of the surface in the area of a dangerous cross-section, one after the other, one after the other. As a result of the thermo-fire treatment of the workpiece on both tooth profile profiles in the area of stress build-up, the strength properties of the msterial are improved and residual stresses are induced, thereby ensuring efficient and broad application of this process for workpieces subjected to any degree of reversibility load. The residual displacements of the reshaped parts of a component under technological loading on one side are reduced due to deformation in the reverse direction. This facilitates the task of achieving the original or other predetermined profile of the work section of the component.

The thermo-manganese hardening process can be carried out according to any technological cycle, and to increase the effect the cycle can be baked several times. At the same time, the contour hardening makes it possible to achieve an increase in the contact strength of the work surfaces of the components and their wear resistance without special technological work processes.

The method consists essentially in an elsstic-plastics bending with simultaneous, rapid succession of surface treatment in the area of dangerous cross-section, which first improves the plastic properties of the msterial in the consolidation zone by rapid heating and then fixes the obtained strengthening by quenching. On one side, this provides the opportunity to improve durability

- Compared to fatigue r to reinforce components with variable direction of load, but not the second stiffness, this leads to a number of drawbacks.

One drawback is that the increase in plasticity of the material is associated with heating and hence. to reduce its strength and to reduce the core of elastic resistance, which somewhat limits the amount of technological bending force, the effect of spatial strengthening, and the size of the reinforced skin. Subsequent surface hardening hardens significantly reduces the plasticity of the material and thus eliminates the continuation of deformation under previous technological load. In addition, the heat treatment apparently increases the sensitivity of the msterial not to the accumulation of stresses, thereby reducing the effect of the spatial strengthening somewhat.

Combining the external force effect and simultaneous heat treatment (full cycle) on one and the same side of the projection profile of the component decreases the stability of the reinforcement e limits the application area of the method to components in which the bending force e heating regions are sufficiently spaced. Partial surface portions of the components between these areas are subject to high strength properties, since the heat treatment produces a transition zone with a reduced strength and remaining tensile stresses. Moreover, these circumstances considerably complicate the design of the hardening device and the technological process of processing the component, and lead to demands with a high number and qualification of operating personnel and high demands on energy consumption.

When the components are subjected to chemical-thermal consolidation, the hardness and strength properties of the surface layer of the material can also be reduced using the method. Changing the state of stress on the faces of the protrusions of the parts further leads to a reduction in the effect of hardening in those cases where the condition of these surfaces affects the load bearing capacity. This also results in an increase in sensitivity and decrease in stability of the scraping mode. the frontal faces β at places remote from these faces. This is particularly evident in the case of considerable plastic deformations of the material.

In strengthening the components with alternating protrusions and depressions, in carrying out said method, a friction of the tangential frictional force results from the necessity of the loading elements of the loading mechanism to the depression of the component of the displacement device. in these depressions. As a result, in the case of components having low angles on the load-bearing surface sections, the mode of loading and the state of stress change markedly. The radial loading component is greater, the effect of bending with shear decreases, the control of the hardening ratios becomes more difficult and also the stability of the hardening decreases.

SUMMARY OF THE INVENTION The present invention seeks to overcome the disadvantages mentioned above. Its object is to provide a method of strengthening machine parts with protuberances and apparatuses for carrying out the method, which would make it possible to carry out the reinforcement by spatial plastic deformation without limitation with respect to the variation of the external load direction and nature of its transformation cycle. the projections of different shape operating in changing the direction of application of the traffic load and the cyclic nature of the application thereof would simultaneously take into account the different processing schemes and would contribute to a significant increase in the ability of the components of the machines with the projections to transmit loads.

This object is solved by a method of strengthening components with protrusions, operating in particular with a variable direction of operating load, which consists in plastic deformation of the protrusion material in bending with strengthening treatment of the protrusion surface in the area of its dangerous cross section. applying a bending force and strengthening the protrusion surface in the area of its dangerous cross-section simultaneously, wherein the strengthening of the protrusion surface in the area of its dangerous cross-section is carried out by applying a normal printing force distributed over this surface.

Strengthening by the method of the invention allows the plasticity of the material to be increased by varying the state of stress n of the surface of the component in the reinforced area, the reinforcement being by spatially plastic deformation of the unstretched side. load and with any cycle of previous thermal or thermochemical treatment. This effect is achieved as a result of the simultaneous increase in plasticity and strength of the material of the surface layer of the component in the area of dangerous cross-section and elastic-pleat bending. ‘

This, as well as the treatment by means of a surface-distributed force which exerts a hydrostatic pressure over the entire area of high bending stresses, makes it possible to apply large bending forces, with the result that spatial bending reinforcement can be applied to the full extent . '

The widening of the sleeves of the parts which can be processed by the method according to the invention, as well as the simplification of the technology and the increase in the stability of the reinforcement, result from the fact that the force and the simultaneous heat treatment are not combined on the same side. Thus, reinforcement can also be carried out on gear-type components with relatively low height of the projections and with high requirements for strength properties outside the area of the dangerous cross-section, as well as on components made of hard-to-hardenable material with considerable stress buildup. The design of the firming equipment and the technological working process are thus considerably simplified, and there is no need for a very high level of qualification of the operating personnel and reduces the demands on their number. Equally, the demands on energy consumption are reduced and not safety equipment.

The method is carried out taking into account the spatial reinforcement specificities which occur when processing the various components.

It is expedient to develop a silo component in addition to the main load, which is distributed over the front surfaces of the projection along the area of its dangerous cross-section. In this way, it is possible to increase the bending plastic deformation of the material and the residual stress in the reinforced area, to reduce the sensitivity not to change the reinforcement parameters, and to increase the load-carrying capacity of the components.

Furthermore, it is expedient to subject adjacent projections of the component, forming together a common depression, to a spatial plastic deformation in bending by subjecting them to the simultaneous action of forces directed from the area of the common depression to opposing directions.

This solution makes it possible to achieve a state of stress of the part with residual phenomena, which according to the nature of the distribution is symmetrical with respect to the depression axis between the reinforced projections, eliminating a change in plastic deformation directions and a sinusoidal reduction of the material slip limit in the projection root. In addition, the technological main forces have opposite signs and compensate each other. The resulting radial forces are also easily compensated, for example, while simultaneously reinforcing diametrically opposed recesses.

The considerable technological forces in the bending of the reinforced projection, which are possible due to the absence of the thermal action of the component and due to a corresponding reduction in the strength properties of the material during processing, increase even more significantly by the force distribution. cross-sectional technological shear force, in the corners, the pressures around ít ”/ 2 are greater than normal tensile stresses.

This peculiarity of the state of stress of the part allows to effectively also strengthen areas which are substantially lower than the dangerous cross section of the projection and avoid gradual strengthening of the material at the bottom of the deepening by mechanical cold forming (which eliminates the snisotropy of the material characterized by Bauachinger effect) at the bottom of the recess).

In addition to the elimination of the Bauschinger effect, in such a scheme of component workload and additional shear and ail acting from joint depression, the region of maximum tensile stresses to the root of the projection e achieves effective reinforcement of the depression bottom, thereby extending the application range to longer types of workpieces β thin rim where the rim is warmly fitted and β small diameter.

It is expedient to exert a simultaneous additional force on the loaded portion of the surface of the reinforced component along the lateral surface of the projection. As a result of this solution it is possible to strengthen it

215 622 components with a complicated projection profile (with profile angles increasing ee towards the top) or with small profile angles. The tangential forces do not increase the radial component of the total load, the tensile stresses of the protuberances on the side of their joint deepening increase, the printing stresses on the opposite sides of their profiles decrease and the nature of the distribution of the existing stresses Despite this fact, the absence of radial components of the tangential forces facilitates controlled control of the reinforcement parameters to facilitate the appearance of the different sections of the surface to be treated.

Furthermore, it is expedient for the working surfaces of the protuberances to be subjected to an additional force which is distributed on the same side of the prefile as the main loading bending force is applied on the same side of the prefil. in lubricant.

Such a solution allows to increase not only the hydrostatic pressure and plasticity of the material, but also the amount of the remaining compressive stresses, the depth of their placement * and the hardness of the surface layer in areas outside the geometric concentrator where the bending stress gradient is substantially lower than in the concentrator. to a significant extent, whereby the effect of spatial plastic deformation is achieved and the boundary on the surface is removed, which would lead to the risk of cracks. At the same time, due to the influence of thermodynamic factors, the temperature increase at high pressure, in combination with plastic deformation, favorable conditions for the adsorption of the active substances are created, which leads to an even greater increase in wear resistance and seizure of components. It also contributes to the improvement of the quality of the surfaces to be treated and to the service life of the reinforcing tool.

Such processing allows the workpiece to be strengthened outside the geometric concentrator region while increasing the amount of flexural bending force as well as the strength of the workpiece in the area of the geometric concentrator. This leads to an increase in the strength of the component.

It is expedient to expose the base body of the component that joins the dangerous projection cross section simultaneously with the plastic deformation of the projections of the compressive force acting in a plane parallel to the dangerous cross section. This makes it possible to reduce the maximum stress at the root of the projection and thereby increase the technological load distributed over its effective profile, as well as the end result of the effect of the reinforcement of the projection, thus improving the overall load bearing capacity of the component.

For thin-rim components, it is also expedient to compress the component at the moment of the projections of the component by a force distributed over the base or mounting surface to achieve the necessary form of rim state and tension that mimics the impact of the bearing in operation. This provides the possibility, in the spatial deformation of the projections in the bend, to mimic the stress field characteristic of the press fit. The overlapping of the two stress states, bending stress and compression stress, during subsequent rolling into the load-bearing component, favorably affects the reproduction of the symmetrical residual stress diagram, the inherent reinforced projections, and the compressive stresses acting on both sides of the hazardous cross-section of the projection. In addition, pressing the root of the projection at the moment of bending increases the normal component of the bending force that is required for consolidation, resulting in an increase in the depth and degree of surface hardening of the active portions of the projections.

It is also expedient that during the processing step of the projection of the component, an additional shear force is exerted in the area of strengthening which counteracts the shear effect of the force causing the plastic surface deformation. This makes it possible to consolidate machine parts with large-length projections with a large arm under bending force, without disturbing the state of stress of the part, since the compensating loads fully realize the advantages of spatial plastic bending.

It is advantageous to expose the base body of the component that is adjacent to the dangerous cross-section area simultaneously by β by deforming the twist projection. This will make it possible to provide reinforcement in the formation of the depth and direction of the predetermined residual stress field in the body of the component, and increase the ability of the component to assume different types of loads from operation, again allowing the service life of gear-type components. , turbine blades, etc. The deformation of the part by twisting creates a plastic enisotropy of the material of its projection, with which the possibilities of controlled bending deformation are in good agreement.

It is also advantageous to exert a load by means of a force uniformly distributed over the surface of the protrusions, caused by the action of the pressurized medium on the surfaces of the adjacent protrusions forming the intermediate depression, on their front surfaces. Such a solution makes it possible to achieve strictly identical load conditions for all of the projections of the component, and contributes to high stability of the strengthening process, minimizes the loss of technological force, reduces wear and thus results in improved product quality and increased equipment used.

The invention further relates to an arrangement for carrying out a method of solidifying machine parts with protrusions, comprising pressure rollers having a cross-sectional tooth shape and a head formed by a transition curve of two adjacent teeth of the treated gear and a heel. wherein, according to the invention, each pressure roller consists of inner plates, side plates and stop plates mounted on a support attached to the foot of the pressure roller, the foot of the pressure roller being formed by inner plates and side plates and having a wedge-shaped cross-section. 20 is equal to the angle between the tangents to the modified profile of two adjacent teeth of the gear being processed, and the pinch roller head is formed by the closure plates.

This solution provides the possibility of subjecting the projections of the workpiece to a spatial plastic deformation while bending the surfaces of the projections in the area of their dangerous cross-section, which contributes to increasing the strength properties of the component material. The high specific pressures that occur at the points of contact between the pressure roller and the peaks of the reinforced projections lead to profile modifications of the heads of these projections.

It is expedient if the inner plates are formed as resilient elements which complement each other and are supported with a gap with respect to the support, and the side plates and e contact these inner plates.

This solution allows all technological processes for spatial plastic bending to be carried out, and at the same time provides the possibility to increase the strengthening effect by utilizing the adaptive properties of the structure of both the device itself and the reinforced material. The use of internal inserts having spring-like characteristics allows to realize technological stresses at any given predetermined accuracy and utilize damping properties of the device which take into account such characteristics of the reinforced component as compliance, manufacturing accuracy of the profile and surface hardness. The construction according to the invention thus makes it possible to gently react to changes in the above parameters and in this case to take advantage of the adaptive properties of the device itself.

It is expedient for the inner plates of the device to be designed, for example, as disc springs, when solidifying machine parts with protrusions which are characterized by different compliance and adaptation properties. This makes it possible to extend the range of application of the device by changing the force characteristics of its elements and introducing non-linear stiffness parameters.

Preferably, the support is provided with holes for supplying lubricant to the internal placement bridges. This makes it possible to bring different types of lubricants to the contact points of the inserts, which substantially changes the friction coefficients and thus the adaptation properties of the device itself. This will give the possibility to adjust these values in a wide range according to the requirements for strengthening conditions.

As a result, the stability of the strengthening process increases.

The invention is explained in more detail in the following description, containing specific examples of conditions and parameters in carrying out a number of technological processes for strengthening the machine parts according to the invention.

Example 1

An exemplary embodiment of the method according to the invention is followed for a single projection component (Fig. 1).

Component for strengthening, forming part of the drive mechanism of mixed feed granulation equipment, designed as shaft with projection 1 of height H - 100 mm with thickness S == 22 mm, with geometric concentrator in the form of circular arc of radius 40 mm, made of chromium-nickel steel with chemical composition: C = 0.45, Si = 0.18, Mn = 0.60, Ni = 1.15, P - 0.035, s = 0.035 and with a yield strength of 58 kp / mm, undergo a spatial plastic deformation a force of 70 kgf / mm not part b of the profile that in dangerous sectional EC creates tension above the yield point of the material, and simultaneously exposed to forces distributed in oblssti hazardous sectional c the treatment with butcher two pushing force B ^₂ kgf / mm, which induces *

normally forces of up to 30 kp / mm, exerting a triaxial state of stress on the surface of the component, the effect of hydrostatic printing, enhancing the plastic properties of the component in the pressure region of the bead, and dropping them on the opposite side of the projection.

As a result, a particular anisotropy of the plastic properties of the component during spatial deformation arises, which makes it possible to obtain a three-layer residual stress diagram and considerable residual negative stress voltages in the peripheral areas of the dangerous cross-section.

After the effect of the force P ^ and the pressure of the punch 2 has passed, the projection 1 of the component is subjected to a spatial plastic deformation with a force P ^ = 80 kp / mm on the side of the cd profile. the distributed forces in the area of the dangerous cross-section ac by the punch pressure 2 with a force Pg * = 80 kp / mm. As a result, spatial deformation occurs only on the cd side, which strengthens the previously obtained three-layer residual stress diagram Cp, indicating the presence of considerable compressive stresses in the region of the perimeter sections of the dangerous cross-section.

The method is carried out using a universal device with hydraulic or mechanical molds and punches.

As a result of processing the part in the manner described, the shaft has the ability to transmit bending loads more than 1.5 times.

Example 2

An example of carrying out the method according to the invention is observed on a component of small thickness with end faces (Fig. 2). The component, which is the drive train for the compound feed granulation equipment, made of steel with a yield strength of 58 kp / mm ² , is loaded with a bending force P ^ = 80 kp / mm which causes plastic deformation of the material in the region of the geometric concentrator with a radius of 20 mm), while at the same time on the trailing side of the projection 1 with a height H ~ 158 mm, a thickness S »34 mm and a length L - 100 mm, a plastic P ₂ - 300 kp / mm with the help of butchers 2, forces Pj = 120 kp / mm, thereby exerting pressure in the areas of plastic deformation of the material.

Various apparatuses may be used to carry out the consolidation method, for example cold-rolling machines with rolls having a diameter approximately equal to half the width of the workpiece, the rolls having coaxial orbiting stops coaxially arranged therewith, and the like.

The aforementioned strengthening of the described type of components does not result in a biaxial state of stress on their end faces (normal stress ^ n ⁼ ® ^e tengecial stress 6 ^ = 0 on the surface not subjected to external loads), which could lead to brittle fracture and for components of low hardness, to increase material n on the faces (and consequently to reduce residual stresses and weaken the part in this area).

The processing of the component in the manner described results in an increase in the service life of the rigid axis of the transmission device by not more than 2.2 times.

Example 3

An exemplary embodiment of a method according to the invention used to process a component with alternating protrusions and depressions shown in FIG. 3 is shown. The diesel locomotive drive rod 6 of the following parameters: module m ~ 10 mm, number of teeth Z = 75, gear rim width b = 140 mm, base profile displacement coefficient X = 0, 437, base profile with profile angle A. = 20 °, with tool radius radius coefficients and tooth head height 0.40 and 1.25, made of steel with yield strength 58 kp / mm, was subjected to sector-hardening of the teeth by high-frequency currents with deburring of the turbid layer.

Adjacent protrusions, i.e., teeth 5, (and the gearwheel are subjected to the simultaneous application of the following forces acting in the region of joint deepening of the teeth, i.e., the gap between them: bending forces P ^ = 300 kp / mm and punch pressure 2 with radial force P ^ In the area of the dangerous cross-section (located at the beginning of the effective profile), the effect of distributed forces is equal to 30 kp / mm and 75 kp / mm in the area of maximum tensile stresses at the tooth base.

215 622

Likewise, the adjacent projections g and 1 forming the adjacent depression are similarly processed by the butcher 2, wherein the forces acting from the region of the common depression, i.e. the forces P ^ with P £, correspond to the above values.

The processing of the component in the manner described results in an increase in the ability of adjacent projections to transmit loads at a level not falling below the values obtained for individual projections, which is more than 50%.

Example 4

An exemplary embodiment of the method of the invention is applied to the processing of the complicated profile component shown in FIG. 4.

Spur gear 4 with straight teeth to be reinforced, intended for a drawbar bar

diesel locomotive, is made of steel with yield strength of 58 kp / mm and is made on the basis of base profile with angle A = 20 °, with module m = 10 mm, number of teeth Z = 75, base profile shift X = 0.437, coefficient radius of radius of tooth of basic tool profile and tooth head height of 0.4 and L, 25 ·

Along the teeth lubricated with liquid hypoid oil, a load device 8, formed in the form of a wedge with a flank angle = 10 ° of effective sections, extends in the depression between the teeth, with its lateral surfaces touching the wheel at the tops of adjacent teeth, base of the indentation, generating a normal force P = = 600 kp / mm, distributed along the length of the gear rim, a distributed normal load of 60 kp / mm, and tangential forces n with the contact surfaces of the wheel teeth of 460 kp / mm respectively.

100 kp / mm.

There is no tangential force in the radial direction, and therefore the compressive force P1, which reduces the effect of the bending force P1, does not increase, which improves the state of stress of the teeth during their strengthening.

The calculations show that the residual, compressive stresses and the extent to which they operate are greatly increased as a result of the processing described above, the degree of this increase being determined primarily by the geometric concentrator band angle and deformation properties of the material. Thus, in the case of teeth with a profile modification of the heel at which this angle decreases even further, a substantially qualitative picture of the spatial deformation of the deformations changes due to the application of a tangential force along the tooth.

Example 5

An exemplary embodiment of the method according to the invention is shown on the component shown in FIG. 6. This component is a toothed rack and a modulus m = 10 mm of steel with a yield strength of 58 kp / mm ² with protrusions

1. The toothed rack is compressed by the butchers J which exert a force of 1000 kp / mm in the direction of the arrows indicated in FIG. 6 with its side walls h = mm, while at the same time the punch 2 is loaded with a force P ^. a force P = 400 kp / mm and forces distributed over the effective sections of cd and ef profiles of the protrusions 1 with an intensity equal to 30 kp / mm ² . The protrusions 1 to be reinforced lie on a compressed foundation, as a result of which the maximum tensile stresses o

in the region of the de concentrator, they decrease by approximately 20 kp / mm and an increase in bending force Ρ _χ is achieved. In this case, the bending stresses in the area of the effective profiles increase and the effect of reinforcing the toothed profile profiles increases.

As a result of the processing of the component in the manner described, an increase in the service life of the components of not approximately three times is achieved.

Example 6

An exemplary embodiment of the method according to the invention is followed in the case of a split load (FIG. 5). The toothed wheel 4 ae is immovably fastened and is loaded on the sb side of the tooth 2 with a bending force P ^ which causes a tension G _N and a plastic deformation in the transition section ac in the region of the geometric concentrator on the tooth surface 5. At the same time, the effective surface of the tooth 5 (in the effective section of the profile) is subjected to an additional force q, which is distributed along the profile such that, together with the bending force, it causes stress in the teeth of the gear above the material proportional limit. Prior to processing, the effective tooth surfaces are coated with a molybdenum disulfide layer.

The result of processing in the manner described is a substantial increase in the contact strength of the gear and its overall load-bearing capacity. Technically and economically useful effect is to increase the lifetime of wheels not many times and reduce the dimensions by 10 to 20 56.

Example 7

An exemplary embodiment of the method according to the invention is followed. processing of thin-rim components (Figs. _Bt 7, 8, 9). As reinforced object is used epicyclic wheel of outer gear of grain threshing machine with module m = 4, number of teeth Z = 69, rim width b = 40 mm, rim width 14.6 mm, diameter of bearing cylinder 0 315 + 0J205 made of standard steel 5 hardness HB = 210 of the following chemical composition: C = 0.18, Mn = 0.85, Cr = 1.1, Ti = 0.1 (in percent).

The deformation of the teeth by the wheel 2 is carried out by means of the gearing elements 8 (Fig. 8), the profile (ebc) of which is shown in Fig. 9.

According to the principle of the proposed method, the epicyclic wheel 2 compresses with a force of 80 Mp distributed over the bearing area (approx. 4.1 kp / mm), thus achieving a correct bearing cylinder clearance in the tolerance field 0 315 + ο'οοο imitates the tension-deformed state of the rim corresponding to the press fit of the wheel 2 in the gearbox.

In three equally spaced depressions of the wheels 2, the loading device 8 is moved along the depressions with a tightening / v of 0.07 and induces a plastic bending deformation of the teeth 2 with a resulting force of 10 MP while simultaneously loading the wheel 2 with a force q = 30 .... 35 kp / mm, which is divided by sections in the area of the dangerous cross-section (transition curve eb) and on the sides of the teeth 5. The teeth 2 are deformed along their entire length to a position corresponding to the modified profile bc.

The same procedure is then repeated for the remaining depressions, bringing the teeth 2 back to their starting position. After all the teeth of the wheel 2 have undergone the said treatment, the loading device 8 is brought out of the recesses with the force distributed over the bearing surface being canceled.

As a result of the processing of thin-rim components such as gear rings according to the method of the invention, the rigidity of the component is increased at the time of consolidation, thereby achieving an unstressed state that corresponds to real operating conditions. This precisely reproduces the predetermined geometrical and strength parameters of the reinforced tooth ring and the nose of the grain threshing device to increase the load to more than 1.8 times, with the kinematic bending being reduced.

Example 8

An example of an embodiment of the method according to the invention is applied to the component shown in Fig. 10. Processed component, which is the axis of the gear mechanism of the compound feed granulation device, made of steel and provided with one protrusion 1 of long length H = 158 mm at S-34 mm, the bending force P ^ = 300 kp / mm shall be loaded at the top of the projection 1, simultaneously on the pulling side of the component by the force distributed in the geometric concentrator area from q = 30 kp / mm and on the opposite side by 660 kp / mm , which acts in the region of the geometric concentrator ef and compensates in the dangerous cross-section sb the additional shear resulting from the distributed force q. Thus, the state of stress of the component is not disturbed by additional shear and the benefits of bending strengthening can be realized.

The technical benefit of using the method described above is to increase the strengthening effect by extending the service life of components with large arms of bending force to approximately 1.3 times.

Example 9

An exemplary embodiment of the method according to the invention with a common bending and twisting is followed (see FIG. 11).

According to the method of the invention, the steel rod 4 of the traction rod is diesel-colloidal. The wheel is made as forged, standardized and refined, with strength properties: hardness (HB) = 255 · «.311, fracture grease strength of 105 kp / mm, and with geometrical parameters: number of teeth Z = 75» modulus m »10 mm, width ring b «140 mm.

Spatial plastic bending processing with simultaneous application of the force distributed in the area of the tooth transition surfaces is performed by a roller tool with a diameter of 120 mm and a technological force of 20 x 10 ^ kp, as well as simultaneous deformation of the wheel all by twisting by two counter moments (M) hydraulic power drive size 220 kp.

As a result of the processing, the ability of the component to transmit the load is increased to 1.2 to 1.3 times, the lifetime of the component ee is increased to 6 to 10 times, and the application area of the method is extended to components different types.

Example 10

The following is an example of an embodiment of the method of strengthening the toothed koalas shown in FIGS. 12, 13.

The wheel 4 is rigidly fixed and the cavity of one of the depressions between the two teeth g, 6 is sealed so that the surfaces abc and cde of the teeth 5 and 6 facing the depressions as well as the faces of the teeth (fig. 13) near the area the accumulation of stress (i.e., the transition curve region) remains free. Into the thus formed enclosed hollow space is introduced 13

215 622 conducts a medium, such as a liquid, that compresses to such a hydrostatic pressure, the height of which is determined by the strength and geometrical parameters of the component to be strengthened, the compressed liquid acting on the free surfaces of the component and causing them to be distributed. Simultaneously with the surface loading, the teeth are reshaped by bending as a result of the bending component of the resultant force that is exerted on each of the blades with a uniformly distributed hydrostatic pressure acting on one side.

The liquid may contain adsorption active substances, for example molybdenum disulfide.

Two-tooth test specimens of 64 x 47 x 28, cut from the spur of the diesel locomotive, with straight teeth, with module m = 11 and number of teeth Z = 68, made of heat-treated steel up to HB hardness, are subjected to such reinforcement. = 311 · ... 255 · Test specimens are milled at storage locations, while front faces are additionally ground to 28 - 0.05 »

The consolidation is carried out in a device provided on a 50 megapond press base, the test sample being loaded by the distributed normal force of the compressed medium acting on the tooth surfaces facing the depressions and on the faces near the stress buildup area, i.e. the transition curve area. The height of the hydrostatic pressure of the cyproplast used as the pressurized medium is 3.3 kbar in this case, resulting in residual displacements of the teeth at the apexes of 0.45 mm, as well as forcing the material in the region of the transition curves of these teeth to 0, 35 mm.

The processing of the component as described above results in improved strength properties, including but not limited to tensile strength, flexural strength, galling resistance, as well as a general increase in load-carrying capacity of 35 to 40%, simplification of component strengthening and extended range of applications the components in question. ' The possibility of over-dosing of technological forces contributing to high stiffening stability is also improved. In addition, the use of a liquid characterized by adsorption activity permits the formation of protective or anti-friction coatings in the components and in this way further improves the performance characteristics.

These examples show that strengthening of machine parts by the method according to the invention makes it possible to achieve a number of advantages over the brewing types of surface reinforcement which are currently widespread and which consist of heat treatment or plastic surface deformation or a combination of both.

The process according to the invention does not have the disadvantages inherent in many thermal methods, such as toxicity, laboriousness and space requirements.

In order to clarify the nature of the invention, specific examples of carrying out a method of strengthening machine parts with protrusions operating in particular with a variable load direction are described, not an example of an apparatus for carrying out the method according to the invention with reference to the drawings. Fig. 15 is a cross-sectional view of the device in the operating position, Fig. 16 is a cross-sectional view of one possible variant of the device according to the invention, also in the operating position, and Fig. 17 is the same cross-section as shown in Fig. 16, but in transit rest.

Fig. 14 shows an example of a manufacturing apparatus in which a gear-strengthening device according to the invention is used.

In the cast frame 10, a reciprocating hydraulic cylinder 11 is mounted vertically, in the upper part of which a mandrel 12 with the gearwheel 8, shown in dashed lines, is fastened to the hydraulic cylinder 11 by means of a pressure bar and a nut 16. The piston rod 18 of the hydraulic cylinder 11 is fixed to the pedestal of the stand 10 and is formed by two concentric tubes 16 and 11, one of which is connected to the upper and the other to the lower inner space of the hydraulic cylinder 11. This arrangement allows the hydraulic cylinder 11, mandrel 12 and The wheel 8 can be moved reciprocally up and down from simultaneous rotation with respect to the piston rod 15 in the direction of the arrow M shown in the figure.

In the upper part of the stand 10, hydraulic cylinders 18 are mounted on the cantilevered supports 18 on both sides of the wheel 6 to press the pressure rollers 20. The pressure rollers 20 are loosely mounted on the transverse axes 11 in the cylindrical bushes 21. Each bushing 21 is supported in ball guides 22. e is connected via the thrust bearing 26 to the piston 2j of the hydraulic cylinder 1g, as a result of which it can freely rotate and move forward.

The device shown in Fig. 15 is formed by a pressure roller 2g (view from Fig. 14 in the direction of arrow A), the profile of which in cross section is in the form of a protrusion, the heel of this protrusion being a wedge 26 connected to the head 26. and 2 g c'ď wedge lines are formed by modifying the heads of two adjacent teeth 5 ^e of a modified profile, which is predetermined by the parameters h, U and / 2AM and which each represent the height profile modification head of the protrusion and the wedge flank angle which is equal to angle between the tangents to the modified toothhead profile 2 ⁸ 6 · The effective sections ab and ab of the head 26 are defined by the transition curves of the tooth profiles 2 and 6 and merge with the wedge sections dc and dc through the curve sections bc and bc *.

A second variant of the projection strengthening device shown in FIGS. 16 and 17 is a structure comprising a plate assembly formed of inner plates 20 for transmitting forces from the outer deformation side plates 2g and the closure plate 20. The inner plates 22 are formed in the form of resilient thrust elements supported on the support 28 and arranged relative to each other with guaranteed gaps K. The side plates 2g and the lock plates 10 are profiled in correspondence with the surface of the teeth 5 and 6 of the treated wheel 6 and rest against the inner plates 22. ·

Fasteners of any known type that limit the axial displacements of the plates in the unloaded state may be used to couple the plate assembly to the common support 28.

During the hardening process, the gap size K is possible in the range 0 = K = K _m8X «where it indicates the gap size in the unloaded state, while a zero value can only occur in the end position of the elastic member at its greatest compression and displacement under maximum loads.

If the force characteristic of the spring member is known, it is possible to determine the magnitude of the gap K by calculating according to standard methodical procedures for springs.

If necessary, when using pressure rollers with a non-linear deformation characteristic, a variant of the design of the deformation plates in the form of disc spring members is also possible.

Lubricant supply channels 21 are provided at the locations of the inner plates 21 with the common support 28.

The apparatus of FIG. 14 operates as follows. The workpiece wheel 4 is mounted and secured to the mandrel by means of a pressure bar 12 and a nut 11. The pressure roller 20, shown in detail in FIGS. 15 and 16, is inserted into a recess between two adjacent teeth 5 and 6 of the wheel 4 and then a predetermined force that causes bending and plastic deformation of the pressure-reinforced component.

During the reinforcement process, the wheel 6 to be processed, together with the hydraulic cylinder 11, undergoes a reciprocating movement. At the same time, the hydraulic cylinders 18 impart a force to the pressure rollers 20, which is determined by the deformation conditions of the teeth 5 and 6. In this case, the pressure rollers 20 move along the recesses of the gearwheel and transform its teeth 5 and 6 to the required degree of strengthening. At the end of each double stroke whose height exceeds the width of the ring gear, for example, the wheel 6 is rotated by a certain angle step, whereupon further pairs of teeth are transformed and so on. After all the teeth of the wheel 4 have undergone a strengthening treatment, the drive mechanism of the device is switched off, and the wheel to be removed is removed.

The effect of using the method according to the invention consists of the following features:

- increased service life,

- increasing the ability of components to withstand loads and hence the power and load capacity of machines;

- reducing the proportion of metal and machine dimensions at the same strength,

- Reducing annual costs not making repairs.

The method according to the invention is well suited for various technological refinement schemes of machine parts and allows for a wide range of universal equipment applications. The simplicity of the process ensures full automation and control of the production process.

Claims (12)

A method of strengthening machine parts with protrusions operating in particular and in a variable direction of operating load, which consists in plastic deformation of the protrusion material in bending and in making processing of the protrusion of the protrusion in the area of its dangerous cross-section by bending force, The reinforcement treatment of the protrusion surface in the area of its dangerous cross-section is carried out by applying a normal pressure force distributed uniformly over the surface of the projection area of the dangerous area of the projection of the component. 2. Method according to claim 1, characterized in that the strengthening of the components with the projections defining the common depression is achieved by applying the bending force and the distributed normal compressive force from the region of the common depression of the projections to opposing directions. 3. A method according to claim 2, characterized in that the bending force β divided by the normal compressive force acts on the projections along their side surfaces. 4. Method according to claims 1 to 3, characterized in that the component is in the area of the dangerous cross-section And, it compresses the projection by counter-directional compressive forces acting in a plane parallel to the plane of the dangerous cross-section, simultaneously acting with the bending force and the distributed normal printing force. 5. A method according to claim 1, characterized in that, under the action of a distributed normal compressive force and a bending force, it is compressed in its base surface until the desired widths are reached. 6. A method according to claim 1, characterized in that, simultaneously with the bending force and the distributed normal compressive force, the projection is subjected to a shear caused by a force applied at the base of the projection and in directions opposite to the direction of the distributed normal compressive force. 7. Method according to claim 1, characterized in that, simultaneously with the action of the bending force and the normal compressive force, the foot of the projection is subjected to a cruel action. 8. The method of claim 7, wherein the bending force and distributed normal compressive force is applied to the surfaces of adjacent depressions forming the depressions together and to the faces thereof by a compressed medium of low viscosity. Apparatus for carrying out the method according to items 1 to 5, in particular for machining gears, comprising pressure rollers having a cross-sectional tooth shape with a head formed by a transition curve of two adjacent teeth of the gear to be treated and a foot; gear, characterized in that each pressure roller (20) consists of inner plates (27), side plates (29) and closing plates (30) mounted on a support (28) connecting to the foot of the pressure roller (20) ), wherein the presser foot (20) is formed by inner plates (27) with side plates (29) and has a wedge (25) in cross-section whose angle (2 * 11) is equal to the angle between tangents to the modified profile of two adjacent of the toothed gear (4) being processed, and the pressure roller head (20) being formed by the closure (30). Device according to Claim 9, characterized in that the inner plates (27) are formed as resilient elements which complement each other and are supported with a gap (K) with respect to the support (28), and the side plates (29) contact these inserts (27) · Device according to claim 9 or 10, characterized in that the side plates (29) are designed as disc springs. Device according to claim 9, characterized in that the support (28) is provided with channels (31) for supplying lubricant to the insertion points of the inner plates (27).