A method of rolling extrusion with regulated axis spacing of axi-symmetrical stepped parts

Description

[0001] The subject of the invention is a method of rolling extrusion with regulated axis spacing of axi-symmetrical stepped parts.

[0002] Until now, there exist and are applied numerous methods of axi-symmetrical stepped forgings manufacturing, full and hollowed, which are used as semi-finished products of stepped shafts, sleeves and others. The most widely applied methods include: die forging on presses and hammers, drawing, forging and piercing, rotary swaging, rotary forging, internal high pressure forming, rolling extrusion in cold, rolling extrusion in cold with deep drilling and cross-wedge rolling. These processes are described in details in the literature by Bartnicki. J, Pater Z. "Cross-wedge processes of hollowed products", ed. Lublin University of Technology, Lublin 2005. As it is given by the authors, the largest products precision is obtained in the drawing processes, however, limits connected with this technology application for manufacturing of hollowed parts are small possibilities within the scope of the obtained elements shapes. The forging technology finds application only in the case of forming of shafts with large dimensions and weight. Yet, piercing is used for thick-walled and short sleeve production. Swaging processes allow for reduction of bars and tubes diameters. Parts formed by means of that method are characterized by large precision, and, at forging on a mandrel, they can possess very accurate cylindrical and conical holes. Another method of hollowed parts manufacturing is hydrostatic extrusion, which allows for forming of products of assumed geometry. In this method, a product is formed under high pressure caused in the element inside. Cold extrusion processes are widely applied in industry for manufacturing of hollowed parts, they form due to extruding by the die hole on mandrel. Recently, numerous ways of forming of hollowed parts basing on cross-wedge rolling and wedge-rolls rolling methods have been worked out. In the cross-wedge rolling and wedge-rolls rolling methods at least one of the forming tools constitutes a flat wedge rolled on a roll, which reduces billet diameter by driving into it, displacing certain metal volume at sides. In the result the product undergoes elongation during forming and the wall thickness in the area of the formed necking lowers. This leads to the product weakening in the area of the rolled step and imposes application of thick-walled billets, which can be formed only in hot conditions Additionally, this method requires usage of complex wedge tools of large dimensions, which results in large implementation costs of the cross-wedge rolling technology.

[0003] From Polish patient application number PL392275 is well known a way of rolling extrusion of hollowed parts, which is based on forming of a semi-finished part in the form of a sleeve or a tube part between three rotating tools. Yet, one of the tools or all tools move additionally in the direction of the semi-finished part axis, putting it into rotation and reducing particular steps of formed multi-stepped shaft. A characteristic feature of this process is tools outline representation on the part external surface, in the result of which section reduction and increase of the product wall thickness take place.

[0004] From Polish patient application number PL393242 is known a way of forming of hollowed products be means of rolling extrusion, which is based on forming of axi-symmetrical hollowed parts from a semi-finished product in the form of a tube. In the described in the claim rolling extrusion process, the semi-finished product is placed in the rotational head, later, it is displaced into the direction of three rotational tools, which are placed around the billet axis every 120°. In the result of tools action, the diameter of external billet pivot is reduced and hollowed stepped part is obtained.

[0005] From the patent application no US2003/140674 is known a spinning process, in which freely rotatable rolls are revolved around a rotating workpiece and are radially displaced in order to shape the workpiece.

[0006] The issue of rolling extrusion process with regulated axis spacing, of stepped axi-symmetrical parts, is the fact that the formed semi-finished product in the form of a bar or a tube part is placed in the front rotational holder seat and the seat of back rotational holder, next the front rotational holder and back rotational holder together with semi-finished product move with a translational motion with constant velocity into the workspace, which is made by the same three formed rolls , next the same three formed rolls are put into rotational motion in the same direction and with the same velocity, then revolution motion of the same three formed rolls is activated and the same three formed rolls are brought closer to the semi-finished product, yet, rotary movement trajectories of the same three formed rolls are of spiral shape, next the semi-finished product is affected by the formed rolls working surfaces and the semi-finished product is put into rotary motion with constant velocity in the direction opposite to the direction of rotations of the same three formed rolls, and, at the same time the semi-finished product is squeezed by working surfaces and the necking is formed on the part circumference.

[0007] An advantage of the invention is the fact that it allows for metal forming of multi-stepped parts of full and hollowed shafts, due to which mechanical characteristics of such manufactured products improve. Thanks to the application of automatic change of the axles distance during rolling extrusion process of parts the process technological possibilities enlarge in comparison with used so far manufacturing methods. The invention gives the opportunity of application of one set of simple rotary tools in the form of rolls for manufacturing of various products, both full and hollowed. The invention is universal and allows for forming of parts from all alloys destined for metal forming.

[0008] The invention is presented in the example of realization in figure, in which Fig.1 shows the beginning of the process and tools and semi-finished product placement in the front view, Fig.2-view from the side of the process and tools at the beginning of rolling extrusion, Fig.3-isometric view of the process, tools and semi-finished product at the beginning of rolling extrusion, Fig.4-view from the front of the process and tools and part placement at the end of rolling extrusion, Fig.5-view of the side of the process and tools at the end of extrusion, yet, Fig.6-isometric view of the process, tools and forging at the end of rolling extrusion.

[0009] The way of rolling extrusion with regulated axis spacing of axi-symmetrical stepped parts is based on that a formed semi-finished product 3 in the form of a bar or tube part is placed in the seat of the front rotary holder 1 and in the seat of the back rotary holder 2. Next, the front rotational holder 1 and back rotational holder 2 together with semi-finished product 3 move with a translational motion with constant velocity V into the workspace. The workspace is made by the same three 4a, 4b and t 4c formed rolls. Next the same three 4a, 4b and 4c formed rolls are put into rotational motion in the same direction and with the same first velocity n₁. Then revolution motion of the same three 4a, 4b and 4c formed rolls is activated with the second velocity n₂ and the same three 4a, 4b and 4c formed rolls are brought closer to the semi-finished product 3. Rotary movement trajectories 7a, 7b and 7c of the same three 4a,4b and 4c formed rolls are of spiral shape. Next the semi-finished product 3 is affected by the 4a, 4b and 4c formed rolls working 4a₁, 4a₂, 4b₁, 4b₂, 4c₁ and 4c₂ surfaces and the semi-finished product 3 is put into rotary motion with the third constant velocity n₃ in the direction opposite to the direction of rotations of the same three 4a, 4b and 4c formed rolls. At the same time the semi-finished product 3 is squeezed by working 4a₁, 4a₂, 4b₁, 4b₂, 4c₁ and 4c₂ surfaces and the necking 5 is formed on the part circumference 6.

Claims

1. Method of rolling extrusion with regulated axis spacing of axi-symmetrical stepped parts characterized in that a formed semi-finished product (3) in the form of a bar or tube part is placed in the seat of a front rotary holder (1) and in the seat of a back rotary holder (2), next, the front rotational holder (1) and back rotational holder (2) together with semi-finished product (3) move with a translational motion with constant velocity (V) into the workspace, which is made by the same three (4a), (4b) and (4c) formed rolls, next the same three (4a), (4b) and (4c) formed rolls are put into rotational motion in the same direction and with a same first velocity (n₁), then revolution motion of the same three (4a), (4b) and (4c) formed rolls is activated with a second velocity (n₂) and the same three (4a), (4b) and (4c) formed rolls are brought closer to the semi-finished product(3), yet rotary movement trajectories (7a), (7b) and (7c) of the same three (4a), (4b) and (4c) formed rolls are of spiral shape, next the semi-finished product (3) is affected by the (4a), (4b) and(4c) formed rolls working (4a₁), (4a₂), (4b₁), (4b₂),(4c₁ )and (4c₂) surfaces and the semi-finished product (3) is put into rotary motion with a constant third velocity (n₃) in the direction opposite to the direction of rotations of the same three (4a), (4b) and (4c) formed rolls and at the same time the semi-finished product (3) is squeezed by working (4a₁), (4a₂), (4b₁), ( 4b₂), (4c₁) and (4c₂) surfaces and a necking (5) is formed on the part circumference (6).

Ansprüche

1. Verfahren zum rotierenden Schubumformen mit einstellbarem Achsenabstand von abgestuften axialsymmetrischen Schmiedestücken, dadurch gekennzeichnet, dass das zu formende Rohstück (3) in Form eines Stabes oder Rohres im Sitz des vorderen Drehhalters (1) und im Sitz des hinteren Drehhalters (2) platziert wird, dann verschieben sich in fortschreitender Bewegung mit konstanter Geschwindigkeit (V) der vordere Drehhalter (1) und der hintere Drehhalter (2) mit dem Rohstück (3) in den Arbeitsbereich, der durch die drei gleichen Formungswalzen (4a), (4b) und (4c) gebildet wird, dann werden die drei gleichen Formungswalzen (4a), (4b) und (4c) in der gleichen Richtung und mit der gleichen Geschwindigkeit (n₁) in die Drehbewegung gesetzt, danach werden die drei gleichen Formungswalzen (4a), (4b) und (4c) mit der Geschwindigkeit (n₂) in die Umlaufbewegung gesetzt und die drei gleichen Formungswalzen (4a), (4b) und (4c) werden in der Richtung des Rohstücks (3) näher gebracht, wobei die Trajektorien (7a), (7b) und (7c) der Umlaufbewegung der drei gleichen Formungswalzen (4a), (4b) und (4c) die Form einer Spirale aufweisen, anschließend wirkt man mittels der Arbeitsflächen (4a₁), (4a₂), (4b₁), (4b₂), (4c₁) und (4c₂) der Formungswalzen (4a), (4b) und (4c) auf das Rohstück (3) ein und setzt man das Rohstück (3) in die Drehbewegung mit konstanter Geschwindigkeit (n₃) in der entgegengesetzten Richtung zur Drehrichtung der drei gleichen Formungswalzen (4a), (4b) und (4c), und das Rohstück (3) wird gleichzeitig mittels der Arbeitsflächen (4a₁), (4a₂), (4b₁), (4b₂), (4c₁) und (4c₂) gewalzt und auf dem Umfang des Schmiedestücks (6) wird eine Verengung (5) geformt.

Revendications

1. La méthode de la poussée rotative, avec l'entraxe réglable, des pièces forgées graduées axisymétriques est caractérisée en ce que le semi-produit forgé (3), sous la forme d'une tige ou d'un tube, est placé dans l'ouverture de la poignée rotative avant (1) et dans l'ouverture de la poignée rotative arrière (2), ensuite on provoque le déplacement, on utilisant un mouvement d'avance à une vitesse constante (V), de la poignée rotative avant (1) et de la poignée rotative arrière (2) avec le semi-produit (3) vers la surface de travail, qui a été créée par trois arbres de formage identiques (4a), (4b) et (4e), ensuite les trois arbres de formage identiques (4a), (4b) et (4e) sont entraînés en rotation dans le même sens et avec la même vitesse (n₁), après quoi, la vitesse de la rotation de trois arbres de formage identiques (4a), (4b) et (4e) est fixée à (n₂) et les trois arbres de formage identiques (4a), (4b) et (4e) sont dirigés vers le semi-produit (3), où les trajectoires du mouvement circulaire(7a), (7b) et (7e) de trois arbres de formage identiques (4a), (4b) et (4e) ont la forme en spirale, ensuite on provoque l'action des surfaces de travail (4a₁), (4a₂), (4b₁), (4b₂), (4c₁) et (4c₂) des arbres de formage (4a), (4b) et (4c) sur le semi-produit (3) et on provoque la rotation du semi-produit (3) à la vitesse constante (n₃) dans le sens inverse par rapport au sens de trois arbres de formage identiques (4a), (4b) et (4e) et simultanément on écrase le semi-produit (3) en utilisant des surfaces de travail (4a₁), (4a₂), (4b₁), (4b₂), (4c₁) et (4c₂) et on forme une striction (5) sur le périmètre de la pièce forgée (6).

Drawing