Method and device for producing at least two hollow bodies each having an opening

Abstract

A method for producing at least two hollow bodies (3, 4), each having an opening (1, 2), on a multi-stage press, in which a semi-finished product (5) is first heated to a forming temperature and then formed in one or more successive forming steps into a pot-shaped molded part (6) which has a base section (10) and the two hollow bodies (3, 4), each having different diameters (d1, d2), which are arranged concentrically and in a stepped manner and are connected to one another by an annular web (8) arranged substantially transversely to a central axis (7) of the molded part (6), and in which the base section (10) of the molded part (6) is subsequently removed and the hollow bodies (3, 4) are each separated from the annular web (8) by axially directed shear forces, wherein the removal of the base section (10) from the molded part (6) and the separation of the hollow bodies (3,4) from the annular web (8) in a single stage of the multi-stage press.,

Description

The invention relates to a method for producing at least two hollow bodies each having an aperture and to a device for producing at least two hollow bodies each having an aperture from a shaped, pot-shaped molded part.DE 25 35 155 A1 discloses a method for producing two ball races, designed as hollow bodies, for ball bearings made of steel rods. The steel rods are first heated to deformation temperature and then divided into sections, which are subsequently pressed via a disk shape into a pot shape, whereupon the bottom of the pot is first removed and the two stages of the remaining hollow cylinder are subsequently separated from one another, wherein the separated stages of the hollow cylinder form the two hollow bodies or raceways of the ball bearing. The method requires a device for cutting the steel rods into individual sections, a pressing device for deforming the respective sections, a further device for forming the sections into the required pot shape, a punching device for punching out the bottom of the pot shape and, furthermore, a cutting device for separating the stepped hollow cylinder into the two raceways or hollow bodies.Furthermore, DE 38 27 985 A1 discloses a large-part step press for producing large-area double parts, and DE 199 58 846 A1 discloses a method for producing elongated swaging pieces on a forging press having a plurality of steps.The closest U.S. Pat. No. 6,065,322 A relates to a method and a device for producing hollow bodies having openings and having different diameters. Described, inter alia, is a production step in which a rotationally symmetrical cup-shaped or pot-shaped component is separated into an inner and outer part and the base part is simultaneously removed from the inner part. In a further, subsequent step, the diameter of the outer part is then increased.Against this background, the object of the invention is to provide firstly a simplified method and secondly an improved apparatus for producing at least two hollow bodies each having an aperture.The first-mentioned object is achieved by a method according to the features of claim 1. dependent claims 2 to 8 relate to particularly expedient developments of the method according to the invention.According to the invention, therefore, a method for producing at least two hollow bodies each having an aperture is provided on a multistage press, in which method firstly a semi-finished product is heated to a deformation temperature and then formed in one or more successive forming steps into a pot-shaped shaped formed part which comprises a base portion and the two hollow bodies each having different diameters, which hollow bodies are arranged concentrically and in a stepped manner and are connected to one another by an annular web arranged substantially transversely to a central axis of the formed part, and in which method the base portion of the formed part is subsequently removed and the hollow bodies are each separated from the annular web by axially directed shear forces, wherein the removal of the base portion from the formed part and the separation of the hollow bodies from the annular web take place in a single stage of the multistage press. By means of the method according to the invention, a total of four components, namely the two hollow bodies with different diameters, the annular web and the bottom section formed as slugs, can be produced in a single press. Because all cutting or shearing processes are carried out in a single stage of the press, the other stages of the press are available for upstream forming processes. As a result, a molded part with geometries matched to the subsequent shearing process can be made available and the shearing stage can be correspondingly relieved. Furthermore, by forming the press with several stages, a nested follow-up tool is provided, by means of which different forming or cutting processes can be carried out in the adjacent stages of the press during a single press stroke. This provides an economical method for producing a plurality of components from a one-piece, pot-shaped molded part.An advantageous embodiment of the method according to the invention is also achieved in that the bottom section in the hollow body with the smaller diameter is removed by a punching die moving in the direction of the central axis of the molded part and an associated punching die, and in that the hollow body with the smaller diameter and the hollow body with the larger diameter are each separated from the annular web by a sleeve-shaped separating die arranged coaxially with the punching die. The corresponding space-saving concentric arrangement of the two punches and the geometric configuration of the molded part make it possible that, in a single stage of the press, on the one hand, the two hollow bodies can be separated from the annular web and, in addition, the base section can also be punched out of the molded part.It has proven to be particularly advantageous if the punch engages in a cup-shaped recess of the smaller hollow body before the bottom portion is removed and the sleeve-shaped separating punch engages in an annular concentrically arranged groove between the two hollow bodies before the two hollow bodies are separated from the annular web. By means of the corresponding geometric configuration or forming of the shaped part in the forming stages arranged upstream, the material thickness in the shear regions can be reduced and the shear stage can thus be relieved accordingly.Furthermore, it has proven particularly expedient if the separation of the hollow body with the larger diameter from the annular web is carried out by a first cutting edge of the separating punch and the separation of the small hollow body from the annular web is carried out by a second cutting edge of the separating punch. As a result, with a single stroke of the separating punch, both hollow bodies are simultaneously separated from the annular web and deburred.Another, particularly advantageous further development of the method according to the invention is also provided in that the small hollow body dips at least partially into a recess between the separating punch and the punching punch during the relative movement between the separating punch and the molded part. This ensures that the sleeve-shaped separating punch can engage in the concentric groove between the two hollow bodies. During a return stroke of the punch after the separating process, the small hollow body initially remains in the recess and is only ejected from the recess by an associated ejector when the punch reaches the starting position.A particularly economical method is also provided in that the separation of the two hollow bodies from the annular web and the removal of the bottom section from the pot-shaped molded part take place during a single stroke of the multistage press.After the hollow bodies have been separated from the annular web, the press is returned to the starting position and the two hollow bodies are carried along by the separating punch and the punching punch during the return stroke. In addition, the annular land is ejected from the punching die. The slug or bottom portion punched out of the small hollow body is removed even shortly after the punching process through an opening in the punching die.The second object mentioned is achieved with a device according to the features of claim 9.According to the invention, therefore, a device is provided for producing at least two hollow bodies each having an aperture from a formed pot-shaped molded part, which comprises a base portion and the two hollow bodies each having different diameters, which hollow bodies are arranged concentrically and in a stepped manner and are connected to one another by an annular web arranged substantially transversely to a central axis of the molded part, wherein the device has a punching die and a sleeve-shaped separating die arranged coaxially with the punching die, and wherein the molded body is arranged in such a way that the base portion of the molded part can be removed by a relative movement between the punching die and an associated punching die, and that the two hollow bodies can simultaneously each be separated from the annular web by a relative movement between the sleeve-shaped separating die and the molded body. This provides a device by means of which a single-piece, preformed shaped part can be separated with a single ram stroke into a total of four components, namely two hollow bodies, an annular element (web) and a rim (bottom section). By virtue of the inventive configuration of the sleeve-shaped separating punch, both hollow bodies are simultaneously separated from the annular web connecting the hollow bodies. During the punching stroke, the slug is also punched out of the small hollow body by the punching punch.An advantageous further development of the invention is also provided in that a centering die is provided for receiving the molded part. As a result, the molded part or the two hollow bodies are positioned and fixed relative to the punching die or the separating die and the punching die.A further feature according to the invention consists in that the sleeve-shaped separating punch has a first cutting edge for separating the larger hollow body from the annular web and a second cutting edge for separating the smaller hollow body from the annular web. Due to the two-blade design of the separating punch with a respective blade for separating the connection of the hollow bodies to the annular web, both hollow bodies can be simultaneously separated from the annular web and deburred with a single stroke of the separating punch.Furthermore, in an expedient development of the invention, it is provided that an inner diameter of the sleeve-shaped separating punch is greater than an outer diameter of the smaller hollow body and an outer diameter of the sleeve-shaped separating punch is smaller than an inner diameter of the larger hollow body. This configuration of the separating punch ensures that the smaller hollow body can enter the space bounded by the separating punch and the punching punch during the separating process of the hollow bodies from the annular web. At the same time, after the hollow bodies have been separated from the web during a return stroke of the punch, the small hollow body is held clampingly by the inner wall surface of the separating punch and the larger hollow body is held clampingly by the outer wall surface of the separating punch, so that the hollow bodies are carried along by the separating punch during a return stroke.The invention permits numerous embodiments. To further clarify its basic principle, one of these is illustrated in the drawing and is described below. This shows in FIGS. 1a to 1d show different representations of a shaped part formed by means of the method according to the invention in the individual stages of a multistage press; FIG. 2 shows a sectional view of a device according to the invention in a front dead point; FIGS. 3 to 8 show representations of the device according to the invention during the shearing process in a time sequence.FIGS. 1a to 1d show various representations for explaining the method according to the invention for producing at least two hollow bodies 3, 4 each having an aperture 1, 2. in the first three stages of a schematically indicated multistage press, a cylindrical semi-finished product 5, which is illustrated in FIG. 1a in dashed lines and has previously been heated to its deformation temperature, is forged or formed into a shaped part 6, which is illustrated in FIG. 1c.The one-piece and pot-shaped molded part 6 has the two concentrically and stepwise arranged hollow bodies 3, 4, which each have different diameters d1, d2and are connected to one another by an annular web 8 arranged transversely to a central axis 7 of the molded part 6. The small hollow body 3 has a bottom section 10 closing a cup-shaped recess 9. Furthermore, the shaped part 6 has an annular groove 11 between the two holder bodies 3, 4 in the region of the web 8 which is arranged concentrically with respect to the central axis 7.After the forming of the shaped part 6 in the first three stages has been completed, the shaped part 6 is disassembled into the individual parts shown in FIG. 1 din a fourth stage designed as a shearing stage. The individual parts are the small hollow body 3 having an aperture 1, for example a ball hub, the large hollow body 4 having an aperture 2, for example a joint piece, and the web 8 designed as a ring and the bottom section 10 designed as studs.FIG. 2 shows the device 12 designed as a shearing stage in a front dead center position. After the molded part has been arranged in a centering die 13, the bottom section 10 or slug, not shown in FIG. 2, was punched out of the small hollow body 3 by a punching die 14 and an associated punching die 15. In addition, the annular web 8 was separated from the two hollow bodies 3, 4 by a sleeve-shaped separating punch 16 arranged coaxially with the punching punch 14. In the end position shown, the small hollow body 3 is arranged in a recess 17 between the punching die 14 and the separating die 16, while the large hollow body 4 is still arranged in the centring die 13.FIGS. 3 to 8 show the different positions of the device 12 during the disassembly of the molded part 6 into its four individual parts.FIG. 3 shows the molded part 6 arranged in the centering die 13 shortly before punching out the bottom section 10 from the molded part 6 or from the small hollow body 3; the punching die 14 is already located in the cup-shaped recess 9 in the small hollow body 3, while the separating die 16 is likewise already located in the annular groove 11 between the two hollow bodies 3, 4. The punching die 15 resting on the small hollow body 3 remains in the position shown in FIG. 3 until the punching process is ended.While the punching die 14 punches out the base section 10, the separating die 16 begins its cut along the contour of the small hollow body 3 and pushes the molded part 6 or the large hollow body 4 deeper into the centering die 13 (FIG. 4 ). At the time shown in FIG. 5, all three cutting edges, namely the cutting edge 18 of the punching die 14 and the two cutting edges 19, 20 of the separating die 16, are in engagement. FIG. 6 shows the process at the time of completion of the shearing process. The annular web 8 is completely separated from both hollow bodies 3, 4; the bottom section 10, not shown, was punched out of the small hollow body 3 and removed through an aperture 21 in the punching die 15. FIG. 7 shows the device 12 in the front dead center position, in which all tools are located in their respective end position.During the subsequent return stroke (FIG. 8 ), the small hollow body 3 and the large hollow body 4 are carried along by the separating punch 16 or by the punching punch 14. The small hollow body 3 is fixed in a clamping manner in the recess 17 formed by the separating die 16 and the punching die 14, while the large hollow body 4 is held in a clamping manner on an outer wall surface 22 of the separating die 16. The outer diameter d1 of the small hollow body 3 is smaller than the inner diameter d3 of the separating punch 16 and the outer diameter d4 of the separating punch 16 is smaller than the inner diameter d5 of the large hollow body 4. the small hollow body 3 is subsequently pressed out of the recess 17 by an ejector 23 arranged coaxially to the punching punch 14, while the large hollow body 4 is removed from the outer wall surface 22 of the separating punch 16 by a stripper plate 24 surrounding the separating punch 16 at least in sections. In addition, the annular land 8 is ejected from the punching die 15.

Claims

Method for producing at least two hollow bodies (3, 4) each having an aperture (1, 2) on a multistage press, in which a semi-finished product (5) is first heated to a deformation temperature and then formed in one or more successive forming steps into a pot-shaped shaped shaped part (6) which has a base portion (10) and the two hollow bodies (3, 4) each having different diameters (d1, d2), which hollow bodies are arranged concentrically and in a stepwise manner and are connected to one another by an annular web (8) arranged substantially transversely to a central axis (7) of the shaped part (6), and in which the base portion (10) of the shaped part (6) is subsequently removed and the hollow bodies (3, 4) are each separated from the annular web (8) by axially directed shear forces, wherein the removal of the base portion (10) from the shaped part (6) and the separation of the hollow bodies (3, 3), 4) from the annular web (8) in a single stage of the multistage press.Method according to claim 1, characterised in that the bottom portion (10) in the hollow body (3) with the smaller diameter (d1) is removed by a punching die (14) moving in the direction of the central axis (7) of the shaped part (6) and an associated punching die (15), and that the hollow body (3) with the smaller diameter (d1) and the hollow body (4) with the larger diameter (d2) are each separated from the annular web (8) by a sleeve-shaped separating die (16) arranged coaxially to the punching die (14).Method according to claim 2, characterised in that the punching die (14) engages in a cup-shaped recess (9) of the smaller hollow body (3) before the bottom portion (10) is removed, and the sleeve-shaped separating die (16) engages in an annular, concentrically arranged groove (11) between the two hollow bodies (3, 4) before the two hollow bodies (3, 4) are separated from the annular web (8).Method according to either of Claims 2 and 3, characterized in that the larger hollow body (4) is separated from the annular web (8) by a first cutting edge (19) of the separating punch (16), and the smaller hollow body (3) is separated from the annular web (8) by a second cutting edge (20) of the separating punch (16).Method according to at least one of the preceding claims, characterized in that the separation of the two hollow bodies (3, 4) from the annular web (8) takes place simultaneously.Method according to at least one of Claims 2 to 5, characterized in that during a relative movement between the separating die (16) and the shaped part (6), the small hollow body (3) dips at least partially into a cutout (17) between the separating die (16) and the punching die (14).Method according to at least one of the preceding claims, characterized in that the separation of the two hollow bodies (3, 4) from the annular web (8) and the removal of the bottom section (10) from the pot-shaped shaped shaped part (6) take place during a single stroke of the multistage press.Method according to at least one of Claims 2 to 7, characterized in that, after the hollow bodies (3, 4) have been separated from the annular web (8), the press is returned to a starting position and, during the return stroke of the press, the two hollow bodies (3, 4) are carried along by the separating punch (16) and the punching punch (14).Device (12) for producing at least two hollow bodies (3, 4) each having an aperture (1, 2) from a shaped, pot-shaped shaped shaped part (6) which has a base portion (10) and the two hollow bodies (3, 4) each having different diameters (d1, d2), which hollow bodies are arranged concentrically and in a stepped manner and are connected to one another by an annular web (8) arranged substantially transversely to a central axis (7) of the shaped part (6), wherein the device (12) has a punching die (14) and a sleeve-shaped separating die (16) arranged coaxially with the punching die (14), and the shaped part (6) is arranged in such a way that the base portion (10) of the shaped part (6) can be removed by a relative movement between the punching die (14) and an associated punching die (15), and in that the two hollow bodies (3, In this case, the spacing of the tubular separating punch (16) from the shaped part (6) can be simultaneously separated from the annular web (8) by a relative movement between the sleeve-shaped separating punch (16) and the shaped part (6).Device (12) according to claim 9, characterised in that a centring die (13) is provided for receiving the shaped part (6).Device (12) according to Claim 9 or 10, characterized in that the sleeve-shaped separating punch (16) has a first cutting edge (19) for separating the larger hollow body (4) from the annular web (8) and a second cutting edge (20) for separating the smaller hollow body (3) from the annular web (8).Device (12) according to at least one of Claims 9 to 11, characterized in that an inner diameter (d3) of the sleeve-shaped separating punch (16) is greater than an outer diameter (d1) of the smaller hollow body (3) and an outer diameter (d4) of the sleeve-shaped separating punch (16) is less than an inner diameter (d5) of the larger hollow body (4).

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