RU2337807C1 - Device for static-pulse rolling of screws - Google Patents

Abstract

FIELD: technological processes.

SUBSTANCE: device consists of two discs with central openings, deformation elements, upper and lower levers, two balancing levers and a load spring and hydraulic hammer fixed at the free end of the lower lever. One of the discs has an inverted-L shape for holding the device on the machine slide, while the other disc is rigidly fixed to the butt-end of the first disc by spacers and screws. The deformation elements are movably installed between the above mentioned discs. The upper and lower levers movably installed on over the other, are located between the discs and are hinged to each other by an axle, installed at one end of the above mentioned levers. One of the balancing levers is rigidly fixed on one end of the lever, and the other is hinged to the other lever. A bearing is installed between the discs. The hydraulic hammer is made under the condition providing for pulse effect on the free end of the upper lever. The deformation elements are in form of deformation roller, made with provision for free rotation on their axes and mounted in pairs on the two given balancing levers. The lower lever in the middle is supported by the bearing collar.

EFFECT: more technological capabilities, lower cost price; increased output and improved quality of processed objects.

5 dwg, 1 ex

Description

The invention relates to the processing of metals by pressure, in particular to surface plastic deformation (PPD) processing of screws, for example screw pumps with a large pitch, cylindrical surfaces, coaxial axis and with an offset axis (eccentrics), for channel screw surfaces having a different diameter, pitch and the diameter of the circumferential circle for rolling in complex cam surfaces and for rolling in PK profiles.

Known three-roller device for rolling in non-rigid shafts, consisting of a holder with rollers, pivotally connected to the housing, which is mounted on the support of the machine [1].

A disadvantage of the known device is the limited use, narrow specialization (only for cylindrical surfaces) and low productivity, while to obtain high quality it is necessary to create large working forces, and this requires the use of rollers with a large profile radius, which negatively affects the overall dimensions and not always feasible.

A device is known for rolling in non-rigid screws, comprising a housing by means of which the device is mounted on a machine support and a holder with deforming elements pivotally connected to the housing, and it is provided with two disks with central holes, one of which is rigidly connected to the housing, and the other disk rigidly attached to the end face of the first disk using spacer sleeves and screws, and between the disks is freely installed using three extensions in the form of tension springs holder, carrying deforming elements, with rings, which are inserted into the end grooves of the holder and axially limit the deforming elements freely located in the groove of the holder’s hole, while to prevent the holder from rotating, it is equipped with a handle located on the periphery, which rests on a roller with an axis fixed between the disks, in addition, stretch springs are fixed on spacer sleeves [2].

The disadvantages of the known device are the narrow specialization and the inability to handle other screw sizes, the inability to adjust the rolling force, which determines the depth of the hardened layer and the degree of hardening.

The objective of the invention is to expand the technological capabilities of the tool by providing a rolling treatment of screw surfaces of screws with a large pitch, as well as a wide range of cylindrical surfaces, coaxial to the axis and with an offset axis (eccentrics), for channel screw surfaces having different diameters, pitch and diameter of the circumference, for rolling in complex cam surfaces and for rolling in PK profiles, as well as reducing costs, increasing productivity and improving the quality of otovleniya through the use of the proposed device, which allows to carry out static and pulsed burnishing on the same machine, which makes the preliminary roughing screw workpiece surface.

The problem is solved by using the proposed device for static-pulse rolling of screws, consisting of two disks with central holes, one of which has an L-shaped holder, with which the device is mounted on a machine support, and the other disk is rigidly attached to the end face of the first disk with using spacer sleeves and screws, and deforming elements made in the form of deforming rollers freely rotating on their axes, which are mounted in pairs on two rocker arms, while the latter installed One of them is rigidly mounted, and the other is articulated on two levers, which, in turn, are articulated by means of an axis mounted on one end of the levers, connected to each other and movably mounted horizontally between the disks one above the other so that the lower arm rests on the outside in the middle a bearing ring mounted between the discs and sitting on an axis, in addition, a hammer is mounted on the other free end of the lower lever, which impulse acts on the free end of the upper lever, and a load spring.

The essence of the device is illustrated by drawings.

Figure 1 shows the processing scheme and the design of the device for static-pulse rolling of non-rigid screws on a lathe, a longitudinal section along aa in figure 2; figure 2 is a top view along D in figure 1; figure 3 is a section along BB in figure 1; figure 4 is a right side view in figure 1; figure 5 is a cross section along G-D in figure 1.

The proposed device is designed for static-pulse rolling of screws with a large pitch, a wide range of cylindrical surfaces, coaxial to the axis and with a displaced axis (eccentrics), for channel screw surfaces having different diameters, pitch and diameter of the circumference, for rolling complex cam surfaces and for Rk-profiles rolling. When processing the proposed device, the screw blank is informed of a rotational movement V _З , and for a device with deforming elements, a longitudinal feed S _ave .

The device consists of two disks 1 and 2 with central holes, one of which, pos. 1, has a L-shaped holder 3, with which the device is mounted on a machine support (not shown).

Another disk 2 is rigidly attached to the end of the disk 1 using spacers 4 and screws 5.

The deforming elements are made in the form of deforming rollers 6, which rotate freely on their axes 7. The deforming rollers 6 are mounted in pairs on two rockers 8 and 9, while the rocker 8 is rigidly mounted using the axis 10 and the pin 11 on the lever 12, and the other rocker 9 pivotally mounted using the axis 13 on the lever 14.

Each of the rocker arms 8 and 9 has two grooves in which there are two rolling rollers 6 installed on the landing with a clearance on the axles 7. The axles relative to the levers are fixed by discs 1 and 2.

The beam 9 has the ability to swing about its axis 13. The beam 9 with the deforming rollers serves as a clamping unit, and the beam 8 in combination with the deforming rollers serves as a guide unit. This allows each roller to be constantly in contact with the machined screw surface and have a stable distributed load on each of the rollers, regardless of their location on the screw surface.

Thus, four rollers cover the rolling surface, evenly spaced, relative to each other. With this arrangement, with the condition of rolling one rocker arm, the rollers well track the rolling surface of almost any profile, moving the levers relative to the disks by means of the lower rocker arm, which serves as a guide assembly.

The levers 12 and 14 are pivotally connected to each other by an axis 15 and are mounted one above the other between the disks 1 and 2, with the middle of the lower lever 12 resting on a support in the form of one or two bearings 16 mounted between the disks and mounted on the axis 17 This support serves to absorb the load of the torque and reduce the friction force when moving the levers in their planetary motion between the disks at the time of running in of any surfaces having an eccentricity.

A hydraulic hammer 18 is mounted on the free end of the lower lever 12, which impulse acts on the free end of the upper lever 14 and the load spring 19. The hydraulic hammer 18 is mounted on the platform 20, which is mounted on the posts 21 and 22 on the free end of the lower lever 12. The output shaft 23 of the hydraulic hammer 18 carries out a pulse load on the anvil 24, which is mounted on the free end of the upper arm 14. The output shaft 23 of the hammer 18 is mounted and located in the compression spring 19, which constantly acts on the upper arm, resting in the plane spite 20.

The proposed device has the ability to run various surfaces in two modes: in the mode of constant loading of the deforming rollers due to the spring when the hammer does not work, and in the pulse-shock rolling mode.

The shock-pulse rolling mode expands the technological capabilities of the device and makes it possible to optimally select the parameters of hardening surface treatment.

To change the compression value of the spring and, accordingly, change the pressure on the rollers in the static rolling mode, it is enough to change the distance l _p or put another spring with the necessary rigidity.

To install and remove the load on the workpiece being processed, a cam 25 is pivotally mounted in the disks 1 and 2 and has a handle 26. The cam 25, when the handle 26 is rotated 90 ° from the position shown in Fig. 1, pushes the levers 12 and 14 and breaks the contact deforming rollers with the workpiece, freeing it from the action of the load.

The operation of the proposed device is as follows.

The device is intended for finishing by surface plastic deformation - rolling in parts such as screws, for example, screws with a channel screw surface, for which the device is installed, for example, in the tool holder of a lathe and a special elongated rotating center of the tailstock (not shown) is passed through the central hole of the disks. The blank of the screw is fixed in the spindle chuck of the front headstock and tighten the center of the tailstock. The workpiece of the screw being machined is provided with a rotational movement V ₃ . The rotation speed of the workpiece is set depending on the required performance, design features of the workpiece, equipment.

Typically, the speed is 3 ... 8 m / min.

The device reports a longitudinal feed S _ol in one direction, which is determined by the formula:

S _ol = kS ₁

where k is the number of deforming elements;

S ₁ - optimal feed per deforming element, is adopted for rollers no more - 0.01 ... 0.08 mm / rev.

In the process of processing the rocker arms leverage on the complex surface of the screw, providing constant guaranteed contact of the deforming rollers with the surface of the part. The levers perform a planetary motion, resting at one end on a fixed support - bearings. This allows you to process the part with a longitudinal feed that is not equal to the pitch (for processing any screw surface by known methods, the longitudinal feed is equal to the pitch of the screw surface). Disks perceive axial forces arising during processing from levers, thereby locating deforming rollers normally to the axis of the workpiece.

The advantages of the proposed device are the reduction of the error of the previous processing; multi-element device allows for multi-pass processing, due to which a higher quality of processing is achieved; allows you to unload the machine components from a one-sided application of force and handle non-rigid (non-rigid parts such as shafts with a length to diameter ratio of more than ten, [6]) are considered screws; the formation of a certain macro- and microgeometric shape of the treated surface, a decrease in the roughness parameter — smoothing of the surface, a change in the structure of the material due to surface hardening, and the creation of a certain stress state — all this favorably affects the wear resistance.

The periodic impulse load P _is carried out using a hammer 18, the output shaft 23 of which acts on the upper lever 14 and then through the rocker 9 to the deforming rollers 6. 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 machined composite 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 device, 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, transverse diameter screw sections - ^27-0.05 mm, eccentricity - 3.3 mm, pitch - 28 ^{± 0.01} mm, 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 with a hydraulic hammer mod. DON UPI with Kar PTI with impact energy A = 250 J, maximum frequency f = 960 min ^-1 and efficiency = 0.47. The values of technological factors (impact frequency, tool roller radius, longitudinal feed value) were chosen in such a way as to provide a 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 and impact-pulse load 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 [3-5]. 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 1.2 ... 1.4 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 the processing by the proposed device is R _a = 0.08 μm, it is possible to reduce the initial roughness by 4 times.

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 is not complicated in design and reliable in operation, and the method of rolling in screw surfaces with a device is simple to implement. The layer structures obtained on the surface of the hardened billet have increased hardness and, accordingly, wear resistance and resistance to fatigue failure.

Using the proposed device allows to increase processing productivity by 1.5 ... 2.0 times and to ensure high accuracy.

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 .: Mechanical Engineering, 1985. P.387, Fig. 6.

2. RF patent No. 2268134, IPC V24V 39/00. Floating device for rolling in non-rigid screws. Stepanov Yu.S., Kirichek A.V., Samoilov N.N., Afanasyev B.I., Katunin A.A., Fomin D.S. Application 2004128667, 09/27/2004; 01/20/2006. Bull. No. 02 is a prototype.

3. RF patent No. 2268135, IPC V24V 39/00. The method of running in non-rigid screws. Stepanov Yu.S., Kirichek A.V., Samoilov N.N., Afanasyev B.I., Katunin A.A., Fomin D.S. Application 2004128668, 09/27/2004; 01/20/2006. Bull. No. 02.

4. RF patent No. 2275288, IPC V24V 39/04. The covering deforming tool. Stepanov Yu.S., Kirichek A.V., Samoilov N.N., Afanasyev B.I., Fomin D.S. Application 2004131325/02, 10.26.2004; 04/27/2006. Bull. No. 12.

5. RF patent No. 2275289, IPC V24V 39/04. Method of surface plastic deformation by female rings. Stepanov Yu.S., Kirichek A.V., Samoilov N.N., Afanasyev B.I., Fomin D.S. Application 2004131340, 10.26.2004; 04/27/2006. Bull. No. 12.

6. Reference technologist-machine builder. In 2 vols. T.1 / Ed. A.G. Kosilova and R.K. Meshcheryakova. - 4th ed., Revised. and add. - M.: Mechanical Engineering, 1986. S. 224 ... 227.

Claims (1)

Device for static-pulse rolling of screws on machines, containing two disks with central holes, one of which has a L-shaped holder for fixing the device on the machine support, and the other disk is rigidly attached to the end face of the first disk by means of spacer sleeves and screws, and deforming elements movably mounted between said disks, characterized in that it is provided with upper and lower levers, which are movably mounted one above the other, are located between the disks and are pivotally connected to each other by means of an axis mounted on one end of the said levers, two rockers, one of which is mounted rigidly on one lever and the other pivotally on the other lever, a bearing mounted between the disks and mounted on the axis, and mounted on the free end of the lower lever by a load spring and a hydraulic hammer, which is made from the condition of providing a pulsed effect on the free end of the upper arm, while the deforming elements are made in the form of deforming rollers with the possibility of free rotation tions on their axes and are mounted in pairs on said two rocker arms and the lower lever middle simply supported on the outer ring of the bearing.

Images