EP0163769A2

EP0163769A2 - A method and a machine for producing a metallic ring with specially contoured surfaces from a ring-shaped blank of selected cross-section

Info

Publication number: EP0163769A2
Application number: EP84115206A
Authority: EP
Inventors: Michael Kransnopolsky; Jacob Katz
Original assignee: Israel Military Industries Ltd; State of Israel
Current assignee: Israel Military Industries Ltd; State of Israel
Priority date: 1984-06-05
Filing date: 1984-12-12
Publication date: 1985-12-11
Also published as: JPS6117336A; EP0163769A3; IL72025A; IL72025A0

Abstract

Manufacture of rings that are contoured on the edge surface and/or the faces. A blank is formed by bending a rod into annular shape and welding the edges together. This blank is then placed into a stamp-type machine wherein the blank is deformed into a ring with the desired contours, the degree of deformation being at least 10%. The invention also provides a tamp-tpye machine for making these rings.

Description

The present invention generally relates to the treatment of metal to form special rings and, more particularly, to a novel method of forming a metallic ring with specially contoured surfaces including inner and/or outer surfaces contoured with grooves, ridges and/or protuberant sections extending in the ring's axial direction.
In some applications a need exists for special flat metallic rings, the speciality being that the ring's inner and/or outer edge surfaces are contoured with grooves and ridges, extending parallel to the ring's axis and spaced apart a chosen distance. There are several known methods for producing such rings. However, they all suffer from at least one or more of the following disadvantages: a) their use results in large losses of scrap metal, sometimes about 50%; b) they are complex; and c) they are inefficient in terms of cost and labor. A need therefore exists for a new method to produce a ring as herebefore described which is highly efficient and free of the above-described disadvantages.
In other cases metallic rings with protruber- ant sections on either or both faces may be required.
In the following specification and claims the term "contoured" will be used for any kind of contouring or profilation of a metal ring on the inner and/or outer edge surface and/or on either face or both faces thereof. The edge surfaces and faces of a contoured metal ring according to the invention will be referred to collectively as "surfaces".
In accordance with the invention there is provided a method of making a metal ring contoured on at least one of its surfaces, comprising:

shaping a metal rod of uniform cross-sectional shape into the shape of a ring with the opposite ends of the ring-shaped rod juxtaposed to one another;
welding said ends together to form a blank to be shaped into the desired ring;
providing a mold assembly comprising first and second members reciprocable with respect to one another and adapted to cooperate with each other so as to form a cavity adapted to be partially occupied by said blank, which cavity is in the shape of the desired metal ring to be formed;
placing said blank on a support surface of either of said first and second members;
applying stress forces to said blank by moving said members toward one another with a force whereby the stress forces applied to said blank are sufficient to lower the resistance of the blank metal to deformation to a minimum so as to cause the blank metal to be deformed and fill the entire cavity;
the cross-sectional area of said rod being so selected that in the finished ring the degree of blank deformation is at least 10% (ten per cent).

It should thus be appreciated that by the use of the present invention there is no loss of metal. Also by causing metal to fill the cavity in said mold assembly as a result of the application of force, a ring with a contoured surface is formed which can bear a heavy load in spite of the fact that a weld seam was made to form the blank.
As will be described hereinafter the ring may have either of the edge surfaces or both of them and/or either or both of its faces contoured. The contours may be of ridges and grooves, as protuberant sections or of any other desired shapes. Where the finished ring is of uniform height, the height of the rod preferably exceeds by at least 10% (ten per cent) the height of the finished ring.
The invention also provides a stamp type machine for making a metal ring by the above method which machine comprises first and second members reciprocable with respect to one another and adapted to cooperate with each other so as to form a cavity adapted to be occupied by a ring blank made of a metal rod whose ends are welded together, one of said members comprising a support surface for said blank and at least one of said members being subjectable to a force so as to apply stress forces to the blank sufficient to cause its deformation, whereby the blank metal fills said cavity.
The invention will best be understood from the following description when read in conjunction with the accompanying drawings. In these drawings;

Fig 1 is a diagram of a metal rod from which the ring is to be formed;
Pigs. 2 and 3 are diagrams of the bent rod, shown in Fig. 1 and the blank formed therefrom, respectively;
Fig. 4 is a diagram, both in top view and cross-sectional view of a ring formed in accordance with the present invention;
Fig. 5 is a cross-sectional diagram of one type of a stamp type mold used to practice the invention;
Fig. 6 is a partial cross-sectional diagram useful in explaining the formation of a novel ring with ridges and grooves on the inner and outer surfaces;
Fig. 7 is a cross-sectional diagram of another type of a stamp type mold in accordance with the invention;
Fig. 8 is a diagram both in top view and cross-sectional view of a differently shaped ring in accordance with the invention;
Figs. 9 and 10 are respectively diagrams of another stamp type mold for forming the ring shown in Fig. 10; and
Figs. 11A - 11D are diagrams of a stamp useful in reducing wear when forming a particularly thick ring or one with complicated contours.

The novel methods of the present invention and the steps thereof may best be appreciated by directing attention first to Figs. 1 and 3. Therein, a metal rod 10, of circular area of a selected diameter, designated D and of a length L between its ends 10a and 10b, is shown. The total metallic volume V is clearly a function of its length L and diameter D. The rod 10 is bent into the shape of a ring, designated by20, so that the rod's opposite ends 10a and 10b are juxtaposed, as represented by the small gap 21. These ends are welded together as represented by 22.
It should be stressed that the rod need not be of circular cross-sectional shape and any other cross-sectional shape may be used. However, the cross-sectional area of the rod designated Ar and its total volume V, have to equal or exceed the cross-sectional area Af and the volume _Vf of the finished ring. Also the height of the ring 20, into which the rod is bent, along its axis has to exceed by not less than 10% (ten per cent) the height of the finished ring.
To distinguish the unwelded ring from the welded one, the latter is designated by 25. It should be pointed out that it is the welded ring 25 of thickness D which is used as a blank in the following steps of the process to form the desired ring with the contoured surfaces. Thus, it may be referred to as blank 25.
One example of the desired ring to be formed from blank 25,is shown in top view in Fig. 4 and is designated by 30. A cross-sectional view along lines I-I is also shown. The thickness of blank 25, i.e. the diameter D of the rod 10 is chosen as a function of the desired thickness T of the finished ring 30, where D>T, while the length L of rod 10 is chosen as a function of the desired overall dimensions of the ring 30 with the particular contoured surfaces. In Fig. 4 the ring 30 is shown with triangularly shaped ridges 35 and grooves 36 of the inner edge surface of the ring. However, other shaped grooves and ridges may be formed, on either or both the outer and inner edge surfaces.
Attention is now directed to Fig. 5 in connection with which the formation of a novel ring such as ring 30 (Fig. 4) with grooves and ridges 36 and 35 on the inner surface from balnk 25 will be described. The ring formation is performed in a stamp type mold, hereafter referred to as stamp 40, with a matrix or blank-supporting member 41. Supported on a bearing or support surface 42 is the blank 25. The blank is placed in position through opening 43. The left half of Fig. 5 designated 5L is used to describe the parts before the ring is formed, while 5R shows the parts after ring formation.
To form the ring, a plunger 45 with a flat surface 46 are provided. It is surface 46 which applies a downward pressure P on the blank 25. Forming part of or connected to the plunger 45 is a die 48 whose outer surface is contoured such as with ridges and grooves generally designated by 50. It is the die's grooves which are filled with metal to form the ring's ridges, while the die's ridges end up forming the ring's grooves.
Once the plunger surface 46 abuts against blank 25 the latter is enclosed from all sides. The only space which is not occupied by metal are the grooves 50 of die 48.
Due to the continued application of the stress force P along the axis, conditions develop which provide for the uneven compression by stresses q1≠ q₂ t q3 t ^q4. Under these conditions the plasticity of the blank metal reaches its maximum and resistance of deformation drops to a minimum. As a result, metal of blank 25 flows radially inwardly, i.e. in the direction perpendicular to the axis into the only available unoccupied space, i.e. the grooves of the die. Clearly, during the deformation the blank is flattened between surfaces 42 and 46. In practice, the degree of blank deformationshould not be less than 10% (ten per cent) meaning that if the cross-sectional area of the blank and finished ring are compared, at least 10% (ten per cent) of the total have moved from the original position in the blank to a new position in the finished ring.
After the deformation is completed the plunger and die are raised and the now-formed ring removed from the block 41. It should be appreciated that the ring formed by the steps just described is ring 30, as shown in Fig. 4. The ridges 35 therein are actually the metal which flowed into the grooves 50 of the die 48 and the grooves 36 are formed by the spaces between the ridges 35 created during the process.
Deformation of the round blank 25 from the circular shape to that of the desired ring with a degree of deformation of at least 10% should be performed at high enough a degree of deformative action to provide at weld seam 22 structure and strength characteristics similar to those of the rod 10.
It should be appreciated that ridges and grooves may likewise be provided to the blank's outer surface (see Fig. 6). This can be achieved by providing the blank supporting member 41 with a die and proper grooves and ridges to engage the outer surface of the blank 25.
Part of the foregoing description may be summarized in connectionwith Fig. 6. It is a partial view of the blank 25 shown with inner die 50 with ridges 35 and grooves 36. An outer die, designated 50a is shown with ridges 35a and grooves 36a. When the pressure P is applied metal, represented by arrows 60, flows to fill inner grooves 36. At the same time metal, represented by arrows 62, flows outwardly to fill outer grooves 36a. Thus, when the ring is finished, its ridges are of metal which during the process flowed into the grooves of the dies.
It should be appreciated that the invention is not limited to forming contours of ridges and grooves only. Many differently shaped contours may be provided to the novel ring in accordance with the present invention. This will further become apparent from the following description.
Attention is now directed to Fig. 7 used to describe one embodiment of ejecting or pushing out the ring 30 from the matrix 41 of stamp 40 after it has been shaped as desired. In Fig. 7 elements like those previously described are designated by like numerals. Also, the left and right parts of Fig. 7, designated 7L and 7R, respectively, show the stamp in the conditions after ring completion and ejection, respectively.
In the embodiment of Fig. 7 a kicker or piston 70 with a push rod 71 are included in member 41 to slide therein. The top of piston 70 is the blank- bearing surface 42 (see Fig. 5). After the ring 30 has been formed, the die 45 is raised, as shown at 7R. Then, as shown in 7R, a force, designated by arrow 75, is applied to the push rod 71 thereby pushing it and the piston 70 upwardly to push or eject the finished ring 30 from the matrix cavity, designated by 77.
Herebefore, it was assumed that the finished ring is of uniform height or thickness, such as shown in Fig. 4 by the letter T. The invention is, however, not intended to be limited thereto and the ring 30 may be shaped to be of different heights along different sections. Also, the invention is not intended to be limited to the formation of grooves and ridges only.
These aspects may best be described in connection with Fig. 8, wherein the ring 30 is shown with several protuberant sections such as bosses 81, 82 and 83 of a height or thickness Tl, while the height of the rest of the ring is T2, where Tl ^> T2. During ring formation, several outer arc-shaped flanges, designated 85, 86 and 87 of height T3 are formed, which are removed in finishing the ring.
Attention is now directed to Figs. 9 and 10 in connection with which a stamp 40 for the formation of a ring like that shown in Fig. 8, i.e. a ring with bosses of a different height or cross-sectional area, such as bosses 81-83 of height Tl in Fig.8, and arc-shaped flanges 85-87 of a lesser height T3 in Fig. 8. The stamp 40 includes a base 91, as shown in the left and right sections 9L and 9R, respectively. The left section 9L shows the stamp during ring formation and 9R after the die was raised.
Fig. 10 is a cross-section along lines III-III in Fig. 9 with the die in the raised position.
The stamp base 91 includes a matrix comprising a lower or bottom part 92 and upper part 93, with a channel 94 therein. A member 96, like piston 70 in Fig. 7, and push rod 97 are included.
As to die 90 it functions both as the plunger 45 and die 48 (Fig. 7). Part of its surface, designated 90a, comes in contact with the upper surface of the blank 30 whereat the ring is to have the lower height. The lower surface has one or more recesses 90b into which during the process metal flows so as to form the bosses with greater height or cross-sectional area. Any excess metal flows into channel 94. The excess metal gets shorn off from the ring, after the die is raised and the piston 96 pushes out the ring 30 by an upward force, provided by rod 97, and in Figs. 9 and 10 channels 94 are shown with shorn-off bits from previous steps.
In Fig. 10 the bosses of the larger cross-sectional area are designated by 101-103, while 104-106 designate the sections of lower height. Numeral 107 designates excess metal from the last formed ring while 108 and 109 designate excess metal from two previously formed rings.
It should be apparent that the matrix and the die which form the cavity within the ring are subjected to considerable wear. This is due to the exposure of their cavity-forming surfaces during the metal deformation. Such wear is particularly great when forming a ring with particularly complicated surfaces of its inner and outer contours or when forming a ring of considerable thickness.
Such wear may be reduced by providing a stamp as shown in Fig. 11A-11D, wherein stages during the formation of a ring from a blank 120 are shown. The stamp designated by 122 comprises the matrix 124 and the die 125. The size of cavity 126 in the matrix extends from top to bottom as shown in these figures and further diagrammed by angles a and 6 each of which is smaller than 90 degrees. The blank 120 rests on the bearing surface 128 of the plunger 130.
As shown in Figs. 11B and 11C, during ring formation due to the force P, due to the deformation of the blank 120 by force P, metal flows radially as well as axially, filling appropriate recess 132 in the matrix 124. As the die 125 pushes on the blank 120 the blank gets further deformed. As shown in Figs. 11B and 11C along its widest cross-section A-A the blank is pressed down by Lh. Due to the angles a and the friction forces on the matrix's surfaces reduces and therefore their wear is reduced. Finally, as shown in Fig. 11D when the plunger 130 is raised to eject the ring (after the die has been withdrawn) the now shaped ring 140 exits out of the section of the cavity with the smallest cross-section. Thereat it undergoes final sizing due to angles a and and the size of the cross-section. With such a stamp reduction of wear to the surfaces of the cavity in the matrix is realizable.
Although particular embodiments of the invention have been described and illustrated herein, it is recognized that modifications and variations may readily occur to those skilled in the art and consequently, it is intended that the claims be interpreted to cover such modifications and equivalents.

Claims

1. A method of making a metal ring contoured on at least one of its surfaces, comprising:

shaping a metal rod of uniform cross-sectional shape into the shape of a ring with the opposite ends of the ring-shaped rod juxtaposed to one another;

welding said ends together to form a blank to be shaped into the desired ring;

providing a mold assembly comprising first and second members reciprocable with respect to one another and adapted to cooperate with each other so as to form a cavity adapted to be partially occupied by said blank, which cavity is in the shape of the desired metal ring to be formed;

placing said blank on a support surface of either of said first and second members;

applying stress forces to said blank by moving said members toward one another with a force whereby the stress forces applied to said blank are sufficient to lower the resistance of the blank metal to deformation to a minimum so as to cause the blank metal to be deformed and fill the entire cavity;

the cross-sectional area of said rod being so selected that in the finished ring the degree of blank deformation is at least 10% (ten per cent).

2. A method according to Claim 1 wherein the finished ring is of uniform height and the height of the rod exceeds the height of the finished ring by at least 10% (ten per cent).

3. A method according to Claim 1 or 2 wherein at least one of the inner and outer edge surfaces of the ring is so shaped as to comprise grooves and ridges extending in the ring's actual direction.

4. A method according to Claim 1 wherein at least one of the sides of the ring is so shaped as to comprise at least one protuberant section.

5. A method according to Claim 1 wherein in forming said ring at least one radial extension is formed by deformation of the blank and the method further comprises the step of shearing off such extension.

6. A stamp type machine for making a metal ring contoured on at least one of its surfaces by the method of Claim 1, which machine comprises first and second members reciprocable with respect to one another and adapted to cooperate with each other so as to form a cavity adapted to be occupied by a ring blank made of a metal rod whose ends are welded together, one of said members comprising a support surface for said blank and at least one of said members being subjectable to a force so as to apply stress forces to the blank sufficient to cause its deformation, whereby the blank metal fills said cavity.

7. A machine according to Claim 6 comprising means for ejecting the finished ring.

8. A machine according to Claim 7 so designed that during ejection the ring is further deformed.

9. A machine according to Claim 7 comprising at least one radial recess extending from said cavity adapted to receive expanding during said deformation to form at least one radial ring extension, the machine being adapted to shear off said extension(s) during ejection.