RU2468884C2 - Method of making rings - Google Patents

Abstract

FIELD: process engineering.

SUBSTANCE: invention relates to production of rings. Initial material is cut into preset-length sections. Then, cutout is made in initial material over its length to produce a blank. Said blank is fitted in the tool. Then, cutout is expanded by forcing male die into blank and applying contracting force to blank ends. Said cutout is expanded unless round blank is obtained.

EFFECT: higher quality.

5 cl, 9 dwg

Description

FIELD OF THE INVENTION

The invention relates to a method for manufacturing a ring, and more specifically, to a method for manufacturing a ring by expanding the middle of the workpiece with a slot while applying a compressive force to the ends of the workpiece.

State of the art

Cylindrical rings are used in many industrial applications. Rings can be processed by pulling, extruding, machining, grinding, and can be used as is. Devices for the manufacture of which rings are used include gear wheels, starter gears, connecting hubs, pulleys, torsional vibration dampers of the crankshaft and many other products.

There are many ways to make cylindrical rings. The most famous methods include: making a hoop from a bar stock with subsequent welding; making a pipe and cutting it into rings; deep drawing of the glass with subsequent removal of the bottom; stretching the workpiece by rolling, forging or casting or extruding the workpiece from sheet metal.

All these processes are suitable for the manufacture of rings, however, when they are used, problems always arise related to the cost or quality of the obtained ring. For example, in welded hoops, when they are subjected to additional molding for the manufacture of gears, pulleys, spline rings, etc., the problem area is the weld. In addition, the operations of welding, cleaning the weld and / or heat treatment to normalize the weld area are expensive.

Cutting seamless pipes is also an expensive process, and making a cup on a press, followed by cutting the bottom, generates excess waste.

A typical example in the art is U.S. Patent 4,590,780, which discloses a method starting with a pre-heated bar, from which a cut piece (41) is formed, in a first molding step carried out on a machine, to form a step-shaped extruded product. In the second molding step, the molded product is subjected to additional molding so that as a result it has an inner ring (J) and an outer ring (A) located coaxially and a radial circular jumper (S) connecting the two rings (J, A). The cut off outer ring (44) is therefore removed at the penultimate stage, and at the last processing step, the inner ring (45), separated from the outer ring, is further processed. This final processing step includes carving out the part (35) going to waste and cutting off the circular jumper (38). It is also possible to perform the molding operation at this last stage of processing, namely, the landing of the remaining inner ring (22a). Through this method, which provides the extraction of the finished outer ring (44) at the last stage of processing, the circular jumper (38) can rest on the entire surface of its cross section during cutting.

There is a need to create a method of manufacturing a ring by expanding the middle of the workpiece with a slot while applying a compressive force to the ends of the workpiece. The present invention satisfies this need.

Disclosure of invention

The main objective of the invention is to provide a method of manufacturing a ring by expanding the middle of the cut preform with a slot while applying a compressive force to the ends of the preform.

Other objects of the invention will be set forth below or become apparent upon examination of the description below and the accompanying drawings.

The invention proposes a method of manufacturing a ring, comprising the steps of: cutting the starting material to a predetermined length, making a slot in the starting material in the direction of its length to form a workpiece, inserting the workpiece into the tool, expanding the middle of the slot with a compressive force applied to the ends of the workpiece, and expand the middle of the slot until the workpiece is round.

Brief Description of the Drawings

The accompanying drawings, which are incorporated in and form a part of the specification, illustrate preferred embodiments of the present invention and, together with the description, serve to explain the principles of the invention.

Figure 1 is a top view of the workpiece.

Figure 2 is a side view of the workpiece in tooling.

Figure 3 is a side view of the workpiece in tooling.

Figure 4 is a perspective view of the workpiece at an intermediate stage.

Figure 5 is a side view of the workpiece in tooling.

6 is a perspective view of the finished ring.

7 is a top view, in perspective, of the workpiece in tooling.

Fig. 8 is a top view of a snap in perspective.

Fig.9 is a side view of a snap in perspective.

Detailed Description of a Preferred Embodiment

The invention provides a method for manufacturing a cylindrical ring from a bar stock. Although a rectangular bar is preferred, any other cross-sectional shape of the bar (round, hexagonal, etc.) may also be used.

The finished ring can be used in the manufacture of gears, pulleys, sprockets, bearing rings, rings of one-way couplings, inertial rings of torsional vibration dampers of the crankshaft and other similar products.

Figure 1 - view of the workpiece in plan. The process begins with a starting material, such as a simple bar, from which a workpiece 10 is cut having the desired length (L) and width (W). The source material may be different from a bar, including rolled products, a round bar, and any other available forms of material. In this example, a rectangular bar is used. The four corners 11 at the edges of the cut rectangular billet are rounded with the help of known technological processes, which facilitates the processing and allows to give the workpiece a uniform thickness.

In the middle of the workpiece, a slot 12 is made, which extends in the longitudinal direction (along the length of the workpiece). The slot can be performed using a laser or other means, including, but not limited to, a high-pressure water jet, a laser, a plasma, abrasive cutting tools, milling, etc. There is a radius of 13 at each end of the slot to prevent cracking during stretching and to maintain uniform thickness. The slot width is minimized to reduce material loss.

Figure 2 is a side view of the workpiece in tooling. Then the workpiece 10 is installed in the press. The thickening and curving contour punch 20 is pressed against the workpiece in the area of the slot, which opens and expands. Initially, the punch contacts the slot in the middle.

The end 22 of the punch contains a blade that engages with the slot 12. The punch 20 is pressed through the workpiece 10 into the receiving matrix 21, using a hydraulic cylinder 200 of known design.

When using the supporting lower matrix 21, the size of which coincides with the final size of the ID ring, the workpiece extends to some extent by approximately 50%, however, it tends to bend and does not continue to expand in the same plane. Therefore, to ensure proper support of the workpiece during its expansion and to prevent its bending during molding, either an expandable (sliding) lower support device or a multi-position device with a gradually increasing hole in the lower part can be used, and a thicker and round punch can be used, than described here.

The largest outer diameter of the punch 20 substantially corresponds to the desired inner diameter of the finished ring (see FIG. 6) minus the machining allowance that may be required.

Figure 3 is a side view of the workpiece in tooling. Since the presence of tensile forces during the processing of metals by pressure is undesirable, and the presence of compressive forces is desirable to prevent stretching of the ends leading to breakage, the present method provides pushing, i.e., the simultaneous application of compressive forces to the ends of the workpiece during expansion by the punch 20.

The application of compressive force to the ends 101, 102 of the workpiece 10 with the simultaneous introduction of the punch 20 into the slot allows you to gradually form a round ring from the workpiece. A compressive force is applied to the ends 101, 102 of the workpiece by means of pads 23, 24. The pads 23, 24 are pressed by known hydraulic cylinders 201 and 202 in a known manner.

Figure 4 is a perspective view of the workpiece at an intermediate stage. Slot 12 is shown partially open. The full diameter of the punch 20 has not yet entered into engagement with the workpiece 10, so it is not yet completely rounded. The pads 23, 24 are engaged with the ends 101, 102 of the workpiece.

Figure 5 is a side view of the workpiece in tooling. The total outer diameter of the punch 20 is in full engagement with the workpiece 10. Therefore, the workpiece 10 is fully rounded. The pads 23, 24 are sandwiched around the preform 10 to control the formation and to prevent the preform from being squared.

6 is a perspective view of the finished ring. The inner diameter ID of the ring 10 is essentially the same as the outer diameter OD of the punch 20.

Once the ring on the punch is finally molded, it is removed from the press, and it is ready for use. If necessary, the ring is ready for additional finishing operations, such as machining, rolling, extrusion, forging, precision dimensional processing, grinding, etc. The molded ring can then be precisely sized in a long die on a press to obtain very accurate dimensions and / or very fine surface treatments.

In yet another embodiment of the method, the workpiece can be expanded by giving it a somewhat square shape, and then rounded off during the normal operation of rotational forging. Other embodiments include running a square billet to form a round ring or using a rolling process to produce a round ring.

In addition, the ring can be processed immediately to obtain the final round shape, and re-installed in the press for final dimensional processing and rounding. The need for these additional operations increases with the use of harder materials, such as alloy steels or high carbon steels. Harder steels can be molded in the above-described press tooling, however, larger diameters may be required at the end of the internal slot to avoid cracking. It may also require molding in hot (usually between 600 and 1000 degrees Celsius) or heat (up to 600 degrees Celsius).

The geometrical parameters of the initial bar stock, namely the length, radius of the outer edges, the diameter of the rounded radii at the ends of the slot and the thickness of the slot, are relevant variables that are easy to choose to optimize accuracy with a minimum amount of waste.

Tooling design is also important to reduce complexity. The equipment may contain one long punch with a sliding lower part or several press compartments with a gradually expanding lower part of the tool and a gradually thickening and rounding upper part of the tool. In addition, in order to prevent breakage at the ends of the slot in the case of using very hard material, the preformed workpiece can be shaped into a “bone” in which very large diameters at the ends of the slot will facilitate the molding process at the ends of the slot.

Fig.7 is a top view in perspective of the workpiece in tooling. The workpiece 10 is shown installed in the faceplate 25. The faceplate 25 controls the position of the workpiece during molding and before it starts. The pads 23, 24 are shown in the retracted position, allowing you to insert the workpiece 10 between them. Elements 27, 26 support a workpiece mounted between the blocks 23, 24.

Pads 23, 24 in FIGS. 7, 8, 9 are similar to those shown in FIGS. 2, 3, 5.

Fig is a top view in perspective of tooling. The blank 10 is not shown to provide a better overview of the elements 26, 27. From the side of the elements 26, 27, a force is applied in the direction of the vector normal to the compressive force vector of the pads 23, 24, and the elements are simultaneously retracted, or apart, relative to each other in interacting with the punch 20 pressed through the slot in the workpiece 10. This allows you to provide the necessary support for the workpiece 10 in the process of its molding. In other words, the elements 26, 27 support the workpiece, preventing it from axial deformation normal to the direction of expansion of the slot. This prevents deformation of the workpiece in the direction of movement of the punch 20. The movement of the punch 20 is considered a movement in the axial direction.

Fig.9 is a side view in perspective of tooling. The punch 20 is shown at the beginning of its insertion into the slot 12. The blade 22 is shown in engagement with the slot 12. The punch 20 is pressed into the slot 12, thereby expanding the middle of the slot, and the pads 23, 24 simultaneously compress the ends of the workpiece. The punch 20 is pressed into the workpiece 10, continuing to expand the middle of the slot until the workpiece becomes round. Then the punch 20 is withdrawn, and the resulting ring is removed.

Although certain embodiments of the invention have been described, it will be apparent to those skilled in the art that various changes can be made to the design and interconnection of elements without departing from the spirit and scope of the invention.

Claims (5)

1. A method of manufacturing a ring, comprising the steps of cutting the starting material to a predetermined length, making a slot in the starting material in the direction of its length to form a workpiece, inserting the workpiece into tooling, expanding the slot by pressing a punch into the workpiece while applying a compressive force to the ends blanks and expand the slot by introducing a punch to obtain a round blank. 2. The method according to claim 1, which further includes maintaining the workpiece in the direction normal to the simultaneously applied compressive force. 3. The method according to claim 1, which further includes cutting the radius at each end of the slot. 4. The method according to claim 1, which further comprises the steps of removing the molded workpiece from the tooling and performing the final processing of the molded workpiece to the final size and shape of the ring. 5. The method according to claim 1, which further includes maintaining the workpiece to prevent axial deformation normal to the direction of expansion of the slot.

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