LT6488B - A composite tool for forming holes with thread in thin-walles parts - Google Patents

Abstract

Was developted a composite tool for forming holes with thread in thin-walled parts for rolling, without chip formation. The formation of a hole and thread with a combined tool generates an economical effect, as eliminating the time between the operations required to change the tool and to determine the new forming modes, and, in the end of rolling the thread, the formed sharpened knuckle is compressed, therefore no additional machining operation is required to remove it. The combined tool consists of seven parts, the first five of which are rounded polygonal cross-sections, smoothly moving to each other in a cone (l), whose purpose is to form a centering hole in a metal wall; a cone (2), the purpose of which is to gradually engage in a hole in the metal; a cylinder (3), the purpose of which is to calibrate the hole to the required diameter for rolling rolling; taper, not less than 2-3 threads, threads (4) purpose is screw in the screws gradually, up to the nominal thread size; a fifth part - a similar polygonal cross-sectional screw surface (5), the purpose of which is to complete the rolling of the screws by rolling; a neck-shaped shoulder (6) of a cylindrical neckline (6) starting at the end of the rolling sleeve and a pin (7) for attaching the tool to the plug.

Description

The invention relates to the field of manufacturing engineering and can be applied to holes and threads in thin-walled metal sheets, thin-walled rectangular, circular or other cross-section rods and structures in metalworking, furniture industry, assembly and assembly of automotive parts and construction.

The combined tooling of holes and threads offers the economic benefit of eliminating the time between operations required to change the tool and the setting of new forming modes, and the finishing of the threaded roller, which eliminates the need for additional machining operations to remove it.

There is a known method and tool for forming a threaded hole in a thin-walled piece using a special tool and device (U.S. Patent No. 7552610 B2). The machine is moved to the working position by means of a robot, an additional metal is fed into the position of the future hole, which is melted with the help of an electric arc and a hole with a neck and a thread are formed with a special tool. The tool consists of a hole-forming part which has a helical groove at the top of the cone, a hole calibration part and a threading part.

The main drawbacks of the method and tool are the limited adaptability, the complex and expensive construction of the device, the need for separate gear for rotating and moving the tool, the additional material feeding mechanism, the electric arc generating equipment. The tool offered is not universal, it is suitable for use only with the proposed equipment, and it does not compress the hub so additional machining operation is needed to remove excess metal from the upper surface of the hole.

There is a known method and tool for forming a hole with a tight thread in a thin-walled piece using a special tool and device (U.S. Patent No. 8827615 B2). The design of the machine and the tool is similar to that of a combined tool (U.S. Patent No. 7552610 B2) but differs in that it utilizes special equipment to heat the workpiece and cool the tool. Due to the difference in temperature between the workpiece and the tool, the surface structure of the metal undergoes phase transitions and forms a stronger thread.

The main disadvantages of the method and the tool are the limited application possibilities, the complicated and expensive construction of the machine, the additional special equipment needed to heat the workpiece and the tool cooling, the limited application area, the additional machining operations to remove excess metal from the upper hole surface. The tool offered is not universal, it is suitable for use only with the proposed equipment, and it does not compress the hub so additional machining operation is needed to remove excess metal from the upper surface of the hole.

A combination tool is known for offering hole and thread forming in thin-walled sheets and hollow sections (German Patent No. DE 19653394 Al). The tool consists of three parts: the first is a rounded polygonal tapered surface, and the second is a rounded polygonal cross-section trapezoidal thread, which is a continuation of the first part, smoothly moving to the third rounded polygonal cross-section.

The main disadvantage of this tool is that the tool does not have the calibration sector required to form a full neck around the hole, and after the drilling and threading operation the surface of the workpiece remains unmachined and requires additional mechanical operation to remove it.

The object of the invention is to form a hole, to calibrate it, to thread a thread and to obtain an economic effect due to the increase of production efficiency, since using the developed tool does not require additional machining operation to remove excess metal from the upper surface of the hole.

The object of the present invention is achieved by the use of a combination tool consisting of 7 parts which, in a gradual transition to each other, form a hole with a thickening neck, clean and calibrate the thread and, at the end of the operation, squeeze the ridge formed at the top of the hole.

The essence of the invention is illustrated in figures.

Figure 7 illustrates a seven-piece construction of a combined drill-screw tool.

Figure 1 shows a cross-sectional shape of the first, second and third parts of the tool.

Figure 4 is a cross-sectional view of the fourth and fifth parts of the tool.

SUMMARY OF THE INVENTION The present invention relates to a combination drilling and threading tool for use in thin-walled metal sheets, thin-walled rectangular, circular, or other cross-section bars and structures without thermoplastic, extruding, forming and calibrating a hole, caused by excess metal extrusion during drilling.

the tool (Fig. 1) is comprised of seven parts, which pass smoothly into one another: the first is a conical surface 1, the purpose of which is to form a centering hole in the metal wall; the second part is a conical surface 2 of rounded polygonal cross-section, the purpose of which is to gradually form a hole in the metal by pushing the excess metal downwards, thereby forming an additional cylindrical surface on the lower side of the wall; the third part is a cylindrical surface 3 of analogous polygonal cross-section, the purpose of which is to calibrate the hole to the diameter required for threading; the fourth part is a conical thread surface 4 of similar polygonal cross-section, not less than 2-3 turns, the purpose of which is to gradually roll the thread to the nominal thread dimension; a fifth part having a cylindrical screw surface 5 of the same polygonal cross-section, the purpose of which is to form a thread by rolling; the sixth part of the tool is a cylindrical surface 6 of cylindrical surface 6 of at least the diameter of a pressed hub, beginning at the end of the thread rolling portion and intended to compress the hub at the end of the thread; seventh part of the tool - stem 7 for securing the tool in the clip (not shown in the drawing). As the thermoplastic hole forms, the hot metal penetrates as the tool penetrates deeper, so that the surfaces of the rounded polygonal tool parts (Figures 2 and 3) are required to push the hot metal not only down and to the edges, thereby forming the required metal. diameter hole and thread tops.

The combined drill-and-screw tool works as follows: For hole forming, due to tool and sheet friction up to 600 ° C and above, the first part of the tool forms a centering hole in part 1, the second part 2 pierces the workpiece. The third part of the tool 3 is for shaping the neck and calibrating the hole to the required thread dimension. When the hole is completed, the thickness of the part in the hole area increases by about 3-4 times the initial thickness of the part, but as the tool becomes deeper into the part, a part of the metal is pushed up and a sharp rib is formed in the upper part. When the tool rotation speed is reduced to the threading speed, the tool part 4 is gradually rolled to the nominal dimension by threading the tool to the desired shape and dimensions 5. At the end of the threading, the tool shoulder 6 compresses the sharp edges of the hub. Then the direction of rotation of the machine tool spindle is changed and the tool is removed from the hole.

Compared to the prototype, the third part of the tool enables more precise shaping of the hole neck, its shape and hole dimension for the thread rolling operation, and at the end the tool shoulder presses the sharpened rib around the hole, eliminating the need for additional machining.

Claims (1)

Definition of the Invention Combined tool for threading holes in thin-walled parts, consisting of seven parts, the first five of which are round polygonal cross-sections, the first and the second of which have a conical surface, the fourth a conical surface of at least 2-3 turns, the fifth is a cylindrical screw surface, the seventh is a rod for fastening the tool in the clamp, characterized in that the third part of the tool is a rounded polygonal cylindrical surface intended to form a cylindrical pin shape and calibrate a hole to the thread rolling dimension; a cylindrical shoulder with a diameter of the pressed rib, beginning at the end of the fourth - thread forming sector, intended to press, after thread rolling, a sharp rib formed by the excess metal extruded during drilling.