RU2493932C2 - Method of barrel production and device to this end - Google Patents

Abstract

FIELD: process engineering.

SUBSTANCE: invention relates to metal forming and may be used in producing 5.45-30 mm-caliber gun barrels. Initial billet is heat treated and machined to produce a pipe. Lead-in part and driving part composed of cylinder with temporary chamber are produced at pipe ends. Annular grooves or cavities with decreasing diameters are formed at cylinder end to be open into each other and into temporary insert cavity. Pipe billet is subjected to radial squeezing at radial squeezer to produce barrel forged piece. Note here that said billet is secured at the machine centers. Driving center incorporates small cylinder with toothed end at front section. Large cylinder with outer grooves without rear walls is arranged at mid section of said center. Said rear part is composed of a shank. Hollow driving center cavity accommodates a hollow thrust center with device to lock it in temporary chamfer. Small cylinder diameter equals that of pipe billet driving part cylinder or exceeds it. Small cylinder is connected with large cylinder by inclined surface.

EFFECT: higher reliability, simplified design.

3 cl, 4 dwg

Description

The invention relates to the processing of metals by pressure and can be used in the manufacture of trunks with threaded or smooth guide parts.

A known method of manufacturing a barrel (see the book. Troitsky ND Deep drilling. - L .: Engineering, 1971, S. 140-141). The blank-forgings are pre-treated on the outer surface, their ends are cut, centering necks and control belts are made and deep drilling is carried out. Next, heat treatment is carried out, a deep hole is bored, grooves are made in it, in the breech part it is a chamber and finally processed on the outer surface, getting a finished barrel.

The disadvantages of the analogue are: the length of the original workpiece is greater than the length of the barrel, taking into account the cutting of the highlanders and the separation of the template from the muzzle for samples — witnesses; therefore, the difference between the volumes of preliminary and final machining is significant, and the metal utilization coefficient (KIM - the ratio of the mass of the barrel to the mass of the initial billet - η) is not more than 30%.

A known method of manufacturing a barrel, adopted as a prototype (see application No. 2009126499/02 (036908), publ. 01/20/2011), in accordance with which the initial billet is first obtained (rolled or forged), then it is processed thermally and mechanically. Then they cut the ends, center one of them, carry out deep drilling, grind it on the outer surface to obtain the inlet part of the cylindrical shape, as well as the lead part in the form of a cylinder, and in its axial hole a technological chamfer is made from the side of this end, get the blank the pipe. After that, a forging of the barrel is obtained from it by radial compression, which is finally mechanically processed and only its entry part is removed to waste.

A device is known for implementing such a method of manufacturing a barrel — a hollow driver center adopted as a prototype (see application No. 2009126499/02 (036908), published on January 20, 2011). The center has in the front part a small cylinder with teeth on the end, in the middle part there is a large cylinder with external grooves without rear walls and a shank in the rear part. A hollow thrust center is located in its front cavity, which protrudes from the end of the small cylinder by the front conical part and has a device for fixing it in the technological facet of the billet-pipe.

The disadvantage of this method is the unreliability of rotation of the workpiece-pipe during radial compression due to the small depth (up to 0.5 mm) of the introduction of intermittent end teeth of the center into the cylinder end of the lead part of the workpiece-pipe, which leads to marriage of the obtained forgings.

The disadvantages of the known device are the lack of strength and durability of the intermittent teeth of the end face of the small cylinder, in connection with which the consumption of the lead centers increases, their complexity and low technology hollow thrust center due to its fixing device.

The group of inventions solves the problem of ensuring the quality of the forgings of the barrel by increasing the reliability of rotation of the billet-pipe during radial compression and simplifying the design of the lead center.

The group of inventions is aimed at achieving technical results consisting in increasing the reliability of rotation of the billet-pipe during radial compression by introducing the teeth of the center to a depth of 2-3 mm in its lead part, and simplifying the design of this center.

The specified technical result is achieved by the fact that in the method of manufacturing a barrel with a threaded or smooth guide part, which includes the formation of the initial billet, its heat treatment and preliminary machining to produce a pipe billet having at its ends a lead-in part and a lead part in the form of a cylinder with a technological bevel in axial hole on the side of its end face, forging by radially crimping a workpiece-pipe on a radial crimping machine with its fastening in the retaining center and in the hollow harness In the center, made with a hollow thrust center, which is fixed on the technological chamfer of the lead part of the workpiece-pipe, the final machining of the forgings with the removal of its lead-in part, in accordance with the invention, ring grooves or cavities with successively decreasing form on the cylinder end of the lead part of the workpiece-pipe diameters, open one into the other and into the cavity of the technological insert.

The implementation of the annular grooves on the end of the cylinder ensures the introduction of the teeth of the center of the lead to a great depth of 2 ... 3 mm in the walls separating the adjacent grooves of this end of the billet pipe, which guarantees its reliable rotation during radial compression.

Formation of a technological chamfer under the hollow thrust center in the axial hole of the billet-pipe with an inclination angle ≤ of the friction angle between the contacting surfaces of the thrust center and this chamfer of the cylinder excludes the displacement of the thrust center from the acting forces during radial compression, which ensures case fixing of the billet-pipe.

The formation from the cylinder end of cavities with decreasing diameters, open one into the other and into the cavity of the technological chamfer of the axial hole of the billet pipe, ensures the introduction of the teeth of the drive center to the maximum depth of the zone of intersection of the end and side surfaces of adjacent cavities, which ensures reliable rotation of the billet pipe with radial compression.

The specified technical result is also achieved by the fact that in the hollow drive center of the radial crimping machine to obtain by radial crimping the billet pipe, having at the ends a lead-in and a lead-in part in the form of a cylinder with a technological chamfer in the axial hole from the side of its end, the forging of the barrel with a threaded or smooth guide part containing in the front part a small cylinder with teeth at the end, a large cylinder in the middle part, made with external grooves without rear walls, and a shank in the rear part, as well as e is located in the center cavity with the protrusion of its front part beyond the end of the small cylinder, a hollow thrust center with a device for fixing it in the technological facet of the pipe billet, in accordance with the invention, the small cylinder is made with a diameter that is equal to or greater than the cylinder diameter of the lead part of the pipe billet him, and connected to a large cylinder with an inclined surface.

The end face with the teeth of the small cylinder is made inclined towards the shank.

The presence of the inclined front end of the small cylinder toward the shank of the lead center with the formation of straight or inclined teeth on this surface guarantees the reliability of rotation of the workpiece-pipe during radial compression due to the introduction of these teeth to the maximum depth in the zone of intersection of the end and side surfaces of the cavities formed from the end of its cylinder .

The use of not straight longitudinal, but inclined longitudinal teeth at the center of the lead increases their service life due to the larger perimeter of contact of such teeth with the corresponding end elements of the cylinder of the lead part of the workpiece pipe.

The invention is illustrated by drawings, where:

figure 1-2 shows embodiments of the breech of the billet pipe;

figure 3-4 - embodiments of a hollow leash center.

The method is as follows.

An initial billet is manufactured and heat treated at a metallurgical enterprise (round rolled or forged), then one of them is centered at the plant, a through hole is drilled, machined to produce a lead-in and a lead-in part in the form of a cylinder, and a technological chamfer in the axial hole is made from its end billet pipes.

Then (see Fig. 1), annular or spiral grooves 1 are formed at the end of the large cylinder, and the technological chamfer 2 in its axial hole is made with an angle of inclination ≤ of the angle of friction between the contacting surfaces of the workpiece-pipe and the hollow thrust center of the drive center.

Figure 2 shows the drive part of the billet-pipe also in the form of a cylinder, from the end of which a cavity 3 of larger diameter is sequentially located, into which a cavity 4 of a smaller diameter is open, and the technological chamfer 2 of the axial hole of the billet-pipe (these cavities be one, two, three, etc., which is determined by the caliber of the barrel).

Figure 3 presents a variant of the lead center, in which at the end of the small cylinder 6, connected to the large cylinder 7 with an inclined surface 8, radial or straight teeth 9 are formed, and at the end of the cylinder 10 of the workpiece-pipe, annular grooves 11 are formed.

A hollow thrust center 12 is placed in the cavity of the lead center, having a flange 13 on the outer side surface under the flange 13 under the side surface of the pin 14, which fixes the hollow thrust center against rotation around the longitudinal axis and restricting its axial movement. Between the rear highlander of this center 12 and the bottom of the cavity is an elastic element 15 (spring, polyurethane sleeve, etc.).

At the rear of the large cylinder 7, grooves 16 are made without rear walls for protrusions of the feed and rotation mechanism of the workpiece-pipe of the radial crimping machine, and behind this cylinder there is a shank 17 located in the socket of this mechanism.

Figure 4 presents a variant of the lead center, in which the end face of its small cylinder 6 is inclined to the shank 17 and along such a conical surface are formed straight or inclined teeth 9, which are in contact with the zones of intersection of the end and side surfaces of the cavities 3 and 4, respectively, larger and smaller diameters formed from the end of the cylinder 10 of the workpiece pipe. In the technological chamfer 2 is also a spring-loaded thrust center 12.

When installing the billet pipe on the center line of the radial crimping machine, its front part is located in the retaining center, and the rear, lead part in the form of a cylinder is located in the lead center. The teeth (radial or straight) are inserted to the maximum depth (up to 3 mm) in the walls between adjacent annular, thereby ensuring the rotation of the workpiece-pipe without stopping during radial compression.

In Fig. 4, the lead center with its straight or inclined teeth formed on its front inclined surface of the small cylinder penetrates to a depth of 3 mm into the zone of intersection of the end and side surfaces of the cavities of the larger and smaller cylinder diameters of the lead part of the billet pipe, which also ensures it reliable rotation during radial compression.

In the manufacture of the barrel, the forging of the barrel is cut from the breech end to remove its annular grooves up to 3-3.5 mm deep or the breech of the barrel is cut to remove cavities of larger and smaller diameters, and the shank with a diameter of ≥38 mm is left as the breech of the barrel (for example - barrel caliber 12.7 machine gun "CORD" has a breech diameter of 38 mm, which then put on the sleeve).

The total length of these cavities or the length of the shank is not more than 8 mm, in contrast to the standard shank with a length of up to 25 mm for billet pipes of trunks of 12.7 mm and 14.5 mm caliber with an unpressed lead part of 67-95 mm in length. Therefore, the breech parts of the standard forgings of the above calibers with a length of up to 60 mm (excluding the length of the shank) are disposed of as waste, which, by weight of the metal of the initial billet with a diameter, for example, 60 mm, is at least 2 kg of steel bar.

In the invention, flaws occur only at a length of 20-40 mm from the cylinder end of the lead part of the resulting forgings, which makes it possible to use this part completely to form the breech of the barrel or to cut it to a length of 8 ... 10 mm to remove cavities.

Hollow leash center operates as follows.

When feeding the billet-pipe 10 with a manipulator to the line of the retaining and driving centers of the radial crimping machine, its drive for feeding and rotating this billet-pipe moves from right to left. In the drive socket with its shank 17 there is a lead center fixed from rotation by grooves 16 in which the protrusions of the drive are located. In this case, the front part of the thrust center 12, protruding beyond the end of the small cylinder 6, due to the spring 15, placed in the cavity formed from the front end of the small cylinder 6, acting on its rear end, gets its outer conical surface into the cavity of the technological insert 2 of the workpiece pipe and fixed there by a spring 15. In this case, the axes of the retaining and driving centers of the radial crimping machine and the pipe billet are combined.

With further movement of the lead center, its thrust center 12 moves backward, compressing the spring 15, and the teeth 9 of the end face of the small cylinder 6 are embedded in the walls between the grooves 11 of the cylinder 10 of the lead part of the billet-pipe to a depth of 3 mm, fixing it in the radial and axial directions, because with its muzzle part it rests against the retaining center.

When using another version of the lead center (Fig. 4), the conical front of the hollow thrust center 12 is also in the technological facet 2 of the cylinder 10 of the workpiece pipe when moving from the drive of the radial crimping machine from right to left. The inclined teeth 9 of the small cylinder 6 are embedded in the metal of the zone of intersection of the side and end surfaces of the cavities 3 and 4 of the cylinder 10 to a depth of at least 3 mm, thereby ensuring reliable rotation of the workpiece-pipe when it is radially crimped. When these teeth are introduced into the indicated zones of the cylinder 10, the thrust center 12 moves in the center cavity from left to right, being securely fixed with its conical front part in the technological facet 2 of the cylinder 10 and additionally compressing the elastic element (spring 15), which abuts against the rear end of the center 12.

When the teeth of the center come into contact with several corresponding elements of the cylinder end of the billet-pipe, their unloading is achieved, i.e. the effective bending and crushing stresses decrease in them, and therefore their resistance increases.

Due to the presence of small 6 and large 7 cylinders, the billet-tube is crimped by the strikers of the radial crimping machine to grooves 11 or cavities 3 and 4 of the end face of cylinder 10, providing an increase in the utilization of the material of the billet and saving at least 2 kg of metal of the initial billet (see earlier given example for a 12.7 mm caliber barrel).

Thus, the proposed group of inventions provides the required quality of the forgings of the barrel by increasing the reliability of rotation of the initial billet pipes during their radial compression, achieved by the introduction of the teeth of the center of the lead to a depth of ≥3 mm in their side parts with reliable fixation of these parts in the center, while ensuring the ability to pinch these blanks with strikers along almost their entire length.

Claims (3)

1. A method of manufacturing a barrel with a threaded or smooth guide part, including the formation of the initial billet, its heat treatment and preliminary machining to produce a billet-pipe having at its ends a lead-in and a lead-in part in the form of a cylinder with a technological chamfer in the axial hole from the side of its end , obtaining forgings by radial crimping on a radial crimping machine of the workpiece pipe with its fastening in the retaining center and in the hollow wire center made with a hollow thrust center, which fi final machining of the forgings with removal of its lead-in part, characterized in that ring grooves or cavities with successively decreasing diameters are formed on one end of the cylinder of the lead part of the billet pipe, open one to the other and to the cavity of the process insertion. 2. The hollow driver center of the radial crimping machine for receiving by radial crimping a billet-pipe having at its ends a lead-in and a lead-in part in the form of a cylinder with a technological chamfer in the axial hole from the side of its end face, forging a barrel with a threaded or smooth guide part, containing in the front part there is a small cylinder with teeth at the end, a large cylinder in the middle part, made with external grooves without rear walls, and a shank in the rear part, as well as located in the center cavity with the protrusion of its front astyu for the end of a small cylinder hollow thrust center of the device it engages in a process chamfer preform-tube, characterized in that the small cylinder is formed with a diameter that equals the diameter of the cylinder the flanged portion of the preform-tube or exceeds it, and is connected to the larger cylinder inclined surface. 3. The center according to claim 2, characterized in that the end face with the teeth of the small cylinder is made inclined toward the shank.

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