Method for manufacturing a ring-shaped molded part and molding apparatus

Abstract

A method of manufacturing an inner ring-shaped formed part and an outer ring-shaped formed part from a blank includes a cup extrusion step of forming a cup having an extended cup base (30) and an adjacent cup wall without a step, and a step of forming the cup wall such that the formed cup wall includes an inner ring-shaped portion (32) and an adjacent outer ring-shaped portion (33) that is axially partially offset from the inner ring-shaped portion (32). The method further includes separating the outer ring-shaped portion (33) from the inner ring-shaped portion (32) and separating the inner ring-shaped portion (32) from the extended cup base (30), wherein the separated outer ring-shaped portion constitutes the outer ring-shaped formed part and the separated inner ring-shaped portion constitutes the inner ring-shaped formed part.

Description

Technical Field

[0001] The present invention relates to a method and an apparatus for manufacturing an inner ring-shaped molded part and an outer ring-shaped molded part from a blank.

Background Art

[0002] In the manufacture of rings for rolling bearings, usually, first, a pair of rings are manufactured by a forming device, one of which forms the inner ring of the rolling bearing and the other forms the outer ring of the rolling bearing. In a known method for manufacturing rings, first, a shaped blank is manufactured from a blank by cup extrusion, and the shaped blank has an inner ring-shaped portion, an outer ring-shaped portion, and a cup base or slug. Thereafter, these ring-shaped portions are separated from each other and from the cup base, for example, as described in European Patent No. 3362204, and are further processed by additional processing steps such as rolling and expansion to form the inner and outer rings of the rolling bearing.

[0003] U.S. Patent No. 6,065,322 discloses a method for manufacturing a shaped blank having two ring-shaped portions and a cup base or slug from a blank in a single forming step by cup extrusion. In this forming method, a stepped forming punch is pressed against the blank disposed in the forming die, and as a result, the two ring-shaped portions and the cup base are formed from the blank in a single forming step. That is, one die is used at one forming station, and the forming station or the die is not changed.

[0004] The ring-shaped portions are arranged so as not to overlap in the radial direction and to be offset in the axial direction, so that the two ring-shaped portions can be separated from each other and further processed to form a rolling bearing ring. For this purpose, a stepped profile of the forming die and a corresponding stepped profile of the forming punch at the forming station are required.

[0005] The problem in this regard is that the stepped profiles of the forming punch and the forming die restrict the flow of the blank material during cup extrusion. The material cannot be displaced without being obstructed by the forming punch, and thus the cup base of the formed part cannot be drawn as thin as desired. Since the cup base or slag is removed and disposed of as waste in subsequent processing steps, an unnecessarily large amount of waste is generated and should be reduced as much as possible.

[0006] Chinese Patent Specification No. 105057556 discloses a method of pre-shaping a cylindrical blank into a cup having a cup wall without a step adjacent to the cup base by cup extrusion first. In the next step, the cup wall and the cup base are further formed into a formed blank having an inner ring-shaped portion, an outer ring-shaped portion, and a remaining base portion at the center of the inner ring-shaped portion. Similar to the method known from US Patent No. 6,065,322, this is done by a stepped forming punch and a stepped forming die, but there is a known problem that the flow of the material is restricted during forming and the material cannot be displaced without being obstructed by the forming punch, and thus the remaining base portion cannot be drawn as thin as desired. Furthermore, after pre-forming, further forming is required for both the pre-formed cup wall and the pre-formed cup base. SUMMARY OF THE INVENTION PROBLEMS TO BE SOLVED BY THE INVENTION

[0007] Against this background, the underlying problem of the present invention is to provide a method and a forming device that can draw out the cup base of a formed blank thinner than known methods using known forming devices, and thus minimize the amount of waste.

Means for Solving the Problem

[0008] This problem is solved by a method according to the invention and a forming device according to the invention for manufacturing an inner ring-shaped forming part and an outer ring-shaped forming part from a blank, as defined in independent claims 1 and 8. Particularly advantageous developments and embodiments of the method according to the invention and the forming device according to the invention will become apparent from the respective dependent claims.

[0009] Regarding the method, the core of the present invention lies in the following. That is, a method for manufacturing an inner ring-shaped forming part and an outer ring-shaped forming part from a blank includes the following steps. Forming a cup having a drawn-out cup base and a cup wall without a step adjacent thereto by cup extrusion of the blank, Forming the cup wall such that the formed cup wall comprises an inner ring-shaped part and an adjacent outer ring-shaped part that is axially partially offset, and Separating the outer ring-shaped part from the inner ring-shaped part, separating the inner ring-shaped part from the drawn-out cup base, and the separated outer ring-shaped part constituting an outer ring-shaped forming part and the separated inner ring-shaped part constituting an inner ring-shaped forming part.

[0010] The advantage of the method according to the invention is that in the first step of the method, a cup is produced having an elongated cup base and a cup wall without steps adjacent thereto, where "stepless" means that the cross-section of the formed cup wall has a contour without steps. Therefore, there is no abrupt transition between regions with different inner or outer diameters in the cup wall. Such a stepless cup wall can accordingly be formed using stepless forming tools, for example a stepless forming punch and a stepless forming die. As a result, the flow of the blank material is not impeded by a stepped shape, and the forming tool, in particular the forming punch, can be displaced without substantially impeding the blank material during cup extrusion. By doing so, a relatively thin cup base can be stretched. In the cup extrusion step, the cup base of the cup is substantially drawn to its final shape, and no further significant forming is carried out in subsequent steps for forming the cup wall. This also means that the thickness of the cup base is fixed in the cup extrusion step and does not change significantly further during the forming of the cup wall. In the case of the method of the prior art described above, the ring-shaped part of the formed cup wall is formed in the same step as the cup base or the remaining base part, but the stepped cross-section of the corresponding forming tool required therefor impedes the flow of the material, and as a result, the cup base or the remaining base part is thicker compared to the method according to the invention.

[0011] The separation of the outer ring-shaped part from the inner ring-shaped part and the separation of the inner ring-shaped part from the elongated cup base can be carried out independently of each other, simultaneously or with a time lag, such that the separated outer ring-shaped part constitutes the outer ring-shaped formed part and the separated inner ring-shaped part constitutes the inner ring-shaped formed part. For example, in a first separation step, the outer ring-shaped part can be separated from the inner ring-shaped part, and in a second separation step, the inner ring-shaped part can be separated from the elongated cup base, or vice versa. These two separation steps can be carried out at the same forming station or at different forming stations.

[0012] The inner ring-shaped molded part and the outer ring-shaped molded part produced by the method according to the present invention are further processed in subsequent processing steps such as rolling and expansion, for example, to form the inner ring and the outer ring of a rolling bearing, as described in, for example, European Patent No. 3362204. Since the cup base is separated and disposed of as waste, the method according to the present invention can reduce the amount of waste by making the cup base thinner. Furthermore, since the required force is small, the energy consumption of the molding process is also reduced.

[0013] Typical materials for the blank for manufacturing such ring-shaped molded parts for further processing into rolling bearing rings include metals such as steel or rolling bearing steel.

[0014] The blank is particularly suitable for the method according to the present invention when its outer diameter substantially coincides with the outer diameter of the outer ring-shaped molded part. The blank is preferably disc-shaped.

[0015] Preferably, during the cup extrusion of the blank, the cup base is formed between the end face of the first forming punch part and the support surface of the ejector.

[0016] By forming the cup base between the end face of the first forming punch part and the support surface of the ejector, there is an advantage that the shape of the forming station can be changed by the movement of the ejector having the support surface. In particular, in a particularly advantageous embodiment in which the ejector is retractable, i.e., arranged to be movable in a direction away from the forming punch, the support surface can be retracted to expose the region of the forming die, particularly the stepped region. As a result, a multi-step forming method using only one forming station becomes possible. Further, after the formation of the cup wall, the formed cup can be easily discharged by the support surface arranged on the ejector, and in any case, no ejection element is required in addition to the ejector having the support surface used for the formation of the cup base.

[0017] Advantageously, during the cup extrusion of the blank, at least a part of the peripheral inner surface of the inner ring-shaped forming part is formed by the peripheral outer surface of the first forming punch part.

[0018] The peripheral outer surface is here to be understood as the side surface that protrudes away from the end face and surrounds the forming punch part laterally of the forming punch part. The first forming punch part configured in this way is advantageous for the displacement of the material of the blank. This can ensure that the material of the blank does not flow behind the end face of the forming punch part during cup extrusion, and this material of the blank has to be displaced again in subsequent steps for forming the cup wall. Further, at least a part of the peripheral inner surface of the inner ring-shaped forming part has already been drawn out as a result, and thus, it is possible to avoid additionally forming its inner surface in subsequent steps for forming the cup wall.

[0019] In an advantageous embodiment, the cup extrusion of the blank is carried out at a first forming station provided with a forming die without a step, and the forming of the cup wall is carried out at a second forming station provided with a forming die having a stepped region.

[0020] In that case, after cup extrusion, the cup from the first forming station having a forming die without a step is transferred to a second forming station having a forming die with a stepped region different from the forming die without a step. This has the advantage that the method according to the invention can be carried out without the need for a movable element for changing the shape of the forming die or a movable element for exposing a part of the forming die that is inaccessible for blank cup extrusion.

[0021] In another advantageous embodiment, the blank cup extrusion and the forming of the cup wall are carried out continuously at the same forming station having only one forming die.

[0022] This embodiment has the advantage that there is no need to transfer the cup from the forming station or the forming die to another forming station or forming die after cup extrusion. Therefore, the time required for transfer can be saved. Furthermore, the gripping tool required for cup transfer and the space for an additional required forming station are also unnecessary.

[0023] Preferably, the forming die comprises a stepped region for forming the cup wall, and the inner peripheral surface of the stepped region of the forming die is exposed by the retraction of an ejector having a support surface.

[0024] This has the advantage that the ejector having a support surface, which is used in any case for the formation of the cup base and the ejection of the formed cup, can also be used for the adaptation of the forming die used for cup extrusion. Therefore, no additional movable element is required for that purpose. This is a simple way to provide a stepped region of the forming die for the formation of the cup wall after cup extrusion. Here, the stepped region of the forming die is understood to be a region of the forming die having a stepped contour in cross-section due to sub-regions of different inner diameters. Such a stepped region of the forming die is necessary for forming the outer surfaces of the inner and outer ring-shaped portions of the formed cup with different outer diameters.

[0025] In a preferred embodiment, the blank cup extrusion and the cup wall forming are performed by hot-forming at a temperature of 500 °C or higher.

[0026] Hot-forming at that temperature facilitates the forming of the blank or cup compared to cold-forming.

[0027] The forming device according to the present invention for manufacturing inner and outer ring-shaped molded parts from a blank comprises the following. A first forming punch part for blank cup extrusion that forms a cup having an extended cup base and an unstepped cup wall adjacent thereto, A second forming punch part and a forming die having a stepped region for forming the cup wall, the forming die comprising an inner ring-shaped part and an adjacent outer ring-shaped part that is axially partially offset therefrom, the second forming punch part and the forming die, and A separation tool for separating the outer ring-shaped part from the inner ring-shaped part and separating the inner ring-shaped part from the extended cup base, the separated outer ring-shaped part constituting the outer ring-shaped molded part and the separated inner ring-shaped part constituting the inner ring-shaped molded part, the separation tool.

[0028] The forming device according to the present invention provides the same advantages as the method according to the present invention.

[0029] As used herein, "stepped" and "unstepped" are understood as described above. In this regard, the first forming punch part and the second forming punch part may be different parts of the same forming punch or parts of two different forming punches. In a preferred embodiment, a suitable separation tool may be a stamping tool. For example, additional tools such as a rolling tool or an expanding tool can also be provided.

[0030] Preferably, the forming device comprises an ejector having a support surface, and the first forming punch part comprises an end surface for forming a cup base during cup extrusion of the blank.

[0031] The ejector is preferably configured both to discharge the formed cup and to provide and hold a support surface during cup extrusion or during forming of the cup wall, and is preferably movable by a hydraulic control actuator. A suitable hydraulic system that provides sufficient support force for the ejector to hold the support surface during cup extrusion or during forming of the cup wall is described in European Patent No. 3362204.

[0032] The support surface of the ejector and the end surface of the first forming punch part are preferably arranged to face each other so that a cup base can be formed between the two surfaces. Preferably, the distance between the end surface and the support surface ranges from 1 mm to 6 mm at the thinnest point to form a cup base of the corresponding thickness.

[0033] In an advantageous embodiment, the first forming punch part comprises a first peripheral outer surface for forming at least a part of the inner peripheral surface of the inner ring-shaped forming part.

[0034] In a further advantageous embodiment, the ejector having a support surface is arranged to be retractable to expose the inner peripheral surface of the stepped region of the forming die for forming the cup wall.

[0035] It should be understood that "retractable" as used herein means movable in a direction away from the forming punch part. The ejector can be retracted, for example, as a result of the force applied to the blank or cup by the first forming punch part.

[0036] In an advantageous embodiment, the first forming punch part, the second forming punch part, and the forming die having a stepped region are part of a common forming station.

[0037] In another advantageous embodiment, the first forming punch part and the forming die without a step are part of the first forming station, and the second forming punch part and the forming die having a stepped region are part of the second forming station.

[0038] The method according to the invention and the forming device according to the invention for manufacturing inner and outer ring-shaped formed parts from a blank will be explained in more detail below with reference to two exemplary embodiments shown in the drawings.

Brief Description of the Drawings

[0039]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

Figure 9

Figure 10

Figure 11

Figure 12

Embodiments for Carrying Out the Invention

[0040] For the following description, the following viewpoints apply. For the purpose of clarifying the drawings, reference numerals are included in the figures, but if they are not described in the directly relevant part of this specification, please refer to the descriptions of those reference numerals in the preceding or subsequent parts of this specification. Conversely, to avoid the drawings becoming overly complex, all reference symbols that are not very relevant for immediate understanding are not included in all figures. In that case, please refer to other figures.

[0041] FIGS. 1 and 2 show cross-sectional views of a forming station of a first exemplary embodiment of a forming apparatus according to the present invention at the end of two processing steps. FIGS. 3 and 4 show two corresponding detailed views. FIGS. 5 to 8 show workpieces typically formed of metal that are processed using the forming apparatus at four different processing stages.

[0042] Figure 1 shows a forming station in a first arrangement at the end of cup extrusion of a disc-shaped blank 3 (see Figure 5) for forming a cup 3' having a cup wall 31. The forming device comprises a machine body 5 and a forming die 1 attached thereto, in which the cup 3' formed from the blank 3 by cup extrusion is arranged. The forming die 1 is bounded by the side facing the machine body 5 by the support surface 45 of an ejector 41 arranged movably. The forming device further comprises a forming punch 2 driven by a punch drive 6. The punch drive 6 comprises a punch drive crank 60 driven by a punch drive shaft 64, connected to a punch drive rod 62 via an articulated connection 63, and further connected to the forming punch 2 via a further articulated connection 61. Cup extrusion rotates the punch drive crank 60 in the rotational direction indicated by the arrow by the punch drive shaft 64, presses the forming punch 2 against the blank 3 arranged in the forming die 1, and forms the blank 3 into the cup 3' by the force of the forming punch 2.

[0043] This arrangement further comprises a hydraulically actuated actuator 70 which is movably attached to the machine body 5 and supports an ejector 41 which is also movably attached to the machine body 5. To move or adjust the actuator 70, a piston 74 firmly connected to the actuator 70 moves forward (in the direction of the forming die 1) and backward (in the direction away from the forming die 1) within a hydraulic chamber 76 of the hydraulic system 7 by a hydraulic medium, in particular hydraulic oil. The actuator 70, the piston 74 and the hydraulic chamber 76 are each cylindrical, although in alternative embodiments they may have other shapes. The hydraulic system 7 further comprises a position measuring device having a measuring electronic system and further hydraulic elements such as a hydraulic source, lines, hydroaccumulators, and a collection tank. In the drawings, these elements are grouped together in a hydraulic block 73. For clarity, only two servo valves 72 for supplying the hydraulic medium to the hydraulic chamber 76 and discharging the hydraulic medium from the hydraulic chamber 76 are shown in the figure among the elements related to the hydraulic system 7. To move the piston 74 and the actuator 70 in the direction towards the forming die 1 or to apply a force in that direction, the hydraulic medium is supplied via the servo valve 72 to the region of the hydraulic chamber 76 behind the piston 74 (i.e., the side of the piston 74 away from the forming die 1) and discharged from the region of the hydraulic chamber 76 in front of the piston 74. Thus, to move the piston 74 in the opposite direction, the hydraulic medium is supplied via the two servo valves 72 to the region of the hydraulic chamber 76 in front of the piston and discharged from the region of the hydraulic chamber 76 behind the piston. The movement of the piston 74 and the actuator 70 firmly connected thereto in the hydraulic system 7 corresponds to that of the prior art and need not be further explained. Further details regarding such a hydraulic system 7 are described, for example, in International Publication No. WO 2017 / 072173.

[0044] The actuator 70 can apply a force to the ejector 41 in the direction of the forming die 1. The hydraulic system 7 used here, similar to the system described in International Publication No. 2017 / 072173, on the one hand, supports the blank 3 during cup extrusion and the cup 3' during the forming of the cup wall 31, and on the other hand, is configured to discharge the formed cup 3'' (see FIGS. 2 and 7) from the forming die 1.

[0045] FIG. 1 shows a forming apparatus in an arrangement where the blank 3 has just been formed into the cup 3'. FIG. 2 shows a forming apparatus in an arrangement where the cup wall 31 of the previously formed cup 3' is being formed in a process step following cup extrusion. As shown in FIG. 2, the actuator 70 is retracted, and as a result, the ejector 41 is also retracted to expose the stepped region of the forming die 1, enabling the formation of the cup wall. Further, the forming punch 2 is disposed on the forming die 1 and is further pressed against the cup 3' that is being formed into the formed cup 3'' by the formation of the cup wall 31. The forming punch 2 is moving by further rotation in the rotational direction indicated by the arrow of the punch drive crank 60.

[0046] Next, with reference to FIGS. 3 and 4, which are diagrams showing details of the forming die 1, the forming punch 2, and the ejector 41, and with reference to FIGS. 5 to 8, which show in cross-section the blank 3, the cup 3', the formed cup 3'', and the inner ring-shaped forming part 39 and the outer ring-shaped forming part 38, a method for manufacturing the inner ring-shaped forming part and the outer ring-shaped forming part from the blank 3 will be described in detail.

[0047] FIG. 3 shows a cross-section of the ejector 41, the forming punch 2, and the forming die 1, with the cup 3' disposed on the forming die 1. This arrangement corresponds to the arrangement shown in FIG. 1 where the blank 3 is being formed into the cup 3' by cup extrusion. Such a disc-shaped blank 3 is shown in FIG. 5. Here, the blank 3 is rotationally symmetric about each dotted line, similar to all other objects and workpieces shown in the cross-sections of FIGS. 6 to 8.

[0048] An enlarged view of the cup 3' is shown in Fig. 6. The cup 3' includes a cup wall 31 without a step having an inner peripheral surface 35'', and an extended cup base 30. The shape of the cup 3' is basically determined by the support surface 45 of the ejector 41, the step surface 15 of the forming die 1 which is arranged in the same plane as the support surface 45 and surrounds the support surface annularly in the arrangement according to Fig. 3, the inner peripheral surface 12 of the forming die 1 without a step, the end face 23 of the first forming punch part 20 of the forming punch 2, and the first outer peripheral surface 21 of the first forming punch part 20. The cup base 30 is formed between the support surface 45 of the ejector 41 and the end face 23 of the first forming punch part 20. The distance between the support surface 45 and the end face 23 is preferably in the range of 1 mm to 6 mm, and in this exemplary embodiment, it is about 3 mm, so the cup base 30 is formed with a thickness corresponding to that distance. The first outer peripheral surface 21 of the first forming punch part 20 forms the inner peripheral surface 35'' of the cup 3'. The latter surface constitutes a part of the inner peripheral surface 35' of the inner ring-shaped forming part 39 shown in Fig. 8. The first forming punch part 20 has a first outer diameter AD1 in the range of 10 mm to 150 mm.

[0049] Fig. 4 shows a cross-sectional view of the same elements as in Fig. 3, corresponding to the arrangement shown in Fig. 2, and the cup 3' has already been formed into the formed cup 3'' by forming the cup wall 31. The formed cup 3'' is shown in Fig. 7. The formed cup 3'' includes an inner ring-shaped part 32 side and an outer ring-shaped part 33.

[0050] The ejector 41 having the support surface 45 retracts, and as a result, the region of the molding die 1 having the first peripheral inner surface 11 is exposed. The region of the molding die 1 having the first peripheral inner surface 11 has a first inner diameter ID1. The region of the molding die 1 having the second peripheral inner surface 12 has a second inner diameter ID2. The first inner diameter ID1 is smaller than the second inner diameter ID2. The first inner diameter ID1 is in the range of 16 mm to 170 mm, and the second inner diameter ID2 is in the range of 22 mm to 190 mm. As a result of the two different inner diameters ID1 and ID2, a step having a stepped surface 15 is formed at the transition between the first peripheral inner surface 11 and the second peripheral inner surface 12. The first peripheral inner surface 11, together with the second peripheral inner surface 12, forms a stepped region 13 of the molding die 1.

[0051] The forming punch 2 is pressed against the cup 3' disposed in the molding die 1, and as a result, the cup wall 31 without a step is formed into an inner ring-shaped portion 32 and an outer ring-shaped portion 33 of the formed cup 3''. The first peripheral inner surface 11 of the molding die 1 forms the peripheral outer surface 37 of the inner ring-shaped portion 32, and the second peripheral inner surface 12 forms the peripheral outer surface 36 of the outer ring-shaped portion 33. The peripheral inner surface 35 (corresponding to a part of the peripheral inner surface 35' of the inner ring-shaped molded part 39) has already been formed in a previous process as a part of the peripheral inner surface 35'' of the cup 3'. The forming punch 2 further includes a second forming punch portion 24 having an outer diameter AD2 in the range of 16 mm to 170 mm. The second peripheral outer surface 22 of the second forming punch portion 24 forms the peripheral inner surface 34 of the outer ring-shaped portion 33. Accordingly, the radial dimension of the formed cup 3'' is determined by the first outer diameter AD1 and the second outer diameter AD2 of the respective forming punch portions, and the first inner diameter ID1 and the second inner diameter ID2 of the respective regions of the molding die 1.

[0052] The cup extrusion for forming the cup 3' and the forming of the cup wall 31 are performed by hot forming at a temperature of 500°C or higher. In an alternative exemplary embodiment, these forming processes may be performed by cold forming.

[0053] After the formation of the cup wall 31, the forming punch 2 separates from the formed cup 3'', and further rotation of the punch drive crank 60 causes the punch drive 6 to separate the forming die 1 again. The formed cup 3'' is then discharged from the forming die 1 by the ejector 41.

[0054] After discharge, in a further processing step (not shown), the outer ring-shaped formed part 38 and the inner ring-shaped formed part 39 are produced from the formed cup 3'' (see FIG. 8). For this purpose, the outer ring-shaped part 33 is separated from the inner ring-shaped part 32 and the inner ring-shaped part 32 is separated from the cup base 30 by means of a suitable separating tool, in particular a stamping tool. The separated outer ring-shaped part 33 forms the outer ring-shaped formed part 38 and the separated inner ring-shaped part 32 forms the inner ring-shaped formed part 39. Furthermore, after separation, the outer ring-shaped formed part 38 and the inner ring-shaped formed part 39 are usually rolled or expanded. The punched-out cup base 30 is disposed of as waste.

[0055] FIGS. 9 and 10 are schematic cross-sectional views of the first forming station and the second forming station of a second exemplary embodiment of the forming apparatus according to the present invention at the end of two processing steps, and FIGS. 11 and 12 are corresponding schematic detailed views. Similar to the case of the first exemplary embodiment, FIGS. 5 to 8 show the workpiece processed using the forming apparatus in four different processing stages.

[0056] FIG. 9 shows the first forming station of the forming device at the end of the cup extrusion of the blank 3 for forming the cup 3'. The first forming station includes a machine body 105 and a flat forming die 101 attached thereto, and the cup 3' formed from the blank 3 by cup extrusion is disposed therein. The forming die 101 is bounded by the side facing the machine body 105 by the support surface 145 of the ejector 141. The forming device further includes a forming punch 102 driven by a punch drive 106. The punch drive 106 includes a punch drive crank 160 driven by a punch drive shaft 164, is connected to a punch drive rod 162 via a multi-joint connection portion 163, and the punch drive rod 162 is connected to the forming punch 102 via a further multi-joint connection portion 161. For the cup extrusion, the punch drive crank 160 is rotated in the rotational direction indicated by the arrow by the punch drive shaft 164, the forming punch 102 is pressed against the blank 3 disposed in the forming die 101, and the blank 3 is formed into the cup 3' by the pressure of the forming punch 102. In the arrangement shown in FIG. 9 where the cup 3' has just been formed, the forming punch 102 has already been displaced to the maximum extent, and further rotation of the punch drive crank 160 cannot further move it in the direction of the cup 3' or the forming die 101.

[0057] Instead, further rotation of the punch drive crank 160 causes the forming punch 102 to move away from the cup 3', move away from the flat forming die 101, and the ejector 141 can discharge the cup 3'.

[0058] To form the cup wall 31, the cup 3' is transferred to the second forming station shown in FIG. 10.

[0059] The second forming station is configured in the same manner as the first forming station, except for the forming die. In the second forming station, the forming die 101 without a step is replaced by a forming die 110 having a stepped area. In this exemplary embodiment, the forming punch 102 is also configured in the same manner as the forming punch 102 of the first forming station, and thus is given the same reference numeral. In another embodiment, it would also be possible to use two different forming punches.

[0060] To form the cup wall 31 of the cup 3' disposed in the forming die 110, the punch drive crank 160 is rotated again in the rotational direction indicated by the arrow by the punch drive shaft 164, and the forming punch 102 is pressed against the cup 3' disposed in the forming die 110. By forming the cup wall 31, the cup 3' is formed into the formed cup 3''. In the arrangement shown in FIG. 10 where the formed cup 3'' has just been formed, the forming punch 102 has already been displaced to the maximum extent, and further rotation of the punch drive crank 160 cannot cause further movement in the direction of the formed cup 3'' or the forming die 110.

[0061] In this second exemplary embodiment, the ejector 141 can also be moved by the actuator 170 in the same manner, but can only be moved to eject the cup 3' from the forming die 101 or to eject the formed cup 3'' from the forming die 110. In this exemplary embodiment, the ejector 141 need not be retractable further. Such an ejection mechanism corresponds to the prior art and will not be described further herein. In an alternative exemplary embodiment, the forming dies 101, 110 can also be bounded by an immovable boundary wall instead of the support surface 145 of the ejector 141, and the cup 3' or the formed cup 3'' can be removed from the respective forming dies 101, 110 from the side facing the forming punch 102.

[0062] FIG. 11 shows a cross-sectional view of the ejector 141, the forming punch 102, and the forming die 101 without steps where the cup 3' is disposed. This arrangement corresponds to the arrangement of the first forming station shown in FIG. 9 where the blank 3 is formed into the cup 3' by cup extrusion.

[0063] The shape of the cup 3' is basically determined by the support surface 145 of the ejector 141, the base surface 115 of the forming die 101 (this base surface is arranged in the same plane as the support surface 145 in the arrangement according to FIG. 11 and surrounds the support surface annularly), the step-free peripheral inner surface 114 of the forming die 101, the end surface 123 of the first forming punch part 120 of the forming punch 102, and the first peripheral outer surface 121 of the first forming punch part 120. The cup base 30 is formed between the support surface 145 of the ejector 141 and the end surface 123 of the first forming punch part 120. In an alternative exemplary embodiment, the support surface 145 may be the surface of a non-movable boundary wall. The first peripheral outer surface 121 of the first forming punch part 120 forms the peripheral inner surface 35'' of the cup 3'. The latter surface constitutes a part of the peripheral inner surface 35' of the inner ring-shaped forming part 39.

[0064] FIG. 12 shows a cross-sectional view of the ejector 141, the forming punch 102, and the forming die 110 with a stepped region 113 where the formed cup 3'' is disposed in the forming die 110. This arrangement corresponds to the arrangement of the second forming station shown in FIG. 10 where the cup 3' has already been formed into the formed cup 3'' by forming the cup wall 31.

[0065] The forming die 110 includes a first peripheral inner surface 111 having a first inner diameter ID1' and a region having a second inner diameter ID2', and the first inner diameter ID1' is smaller than the second inner diameter ID2'. A step is formed at the transition between the first peripheral inner surface 111 and the second peripheral inner surface 112, and the first peripheral inner surface 111 and the second peripheral inner surface 112 constitute the stepped region 113.

[0066] The forming punch 102 is pressed against the cup 3' disposed in the forming die 110. As a result, the cup wall 31 without a step is formed into the inner ring-shaped portion 32 and the outer ring-shaped portion 33 of the formed cup 3''. The first peripheral inner surface 111 of the forming die 110 forms the peripheral outer surface 37 of the inner ring-shaped portion 32, and the second peripheral inner surface 112 forms the peripheral outer surface 36 of the outer ring-shaped portion 33. The peripheral inner surface 35 (which corresponds to a part of the peripheral inner surface 35' of the inner ring-shaped forming part 39) has already been formed in a previous process as a part of the peripheral inner surface 35'' of the cup 3'. The forming punch 102 further includes a second forming punch portion 124 having an outer diameter AD2' larger than the first outer diameter AD1'. The second peripheral outer surface 122 of the second forming punch portion 124 forms the peripheral inner surface 34 of the outer ring-shaped portion 33.

[0067] The outer diameters AD1', AD2' and the inner diameters ID1', ID2' respectively correspond to the outer diameters AD1, AD2 and the inner diameters ID1, ID2 of the first exemplary embodiment.

[0068] Subsequent processing steps for manufacturing the outer ring-shaped forming part 38 and the inner ring-shaped forming part 39 correspond to the steps of the first exemplary embodiment, and thus will not be repeated here.

Claims

1. A method for manufacturing an inner ring-shaped molded part (39) and an outer ring-shaped molded part (38) from a blank, comprising: a cup extrusion step of a blank (3) for forming an extended cup base (30) and an adjacent cup wall (31) without a step; a step of forming the cup wall (31) such that the formed cup wall includes an inner ring-shaped portion (32) and an adjacent outer ring-shaped portion (33) that is axially partially offset therefrom; a step of separating the outer ring-shaped portion (33) from the inner ring-shaped portion (32) and separating the inner ring-shaped portion (32) from the extended cup base (30), wherein the separated outer ring-shaped portion constitutes the outer ring-shaped molded part (38) and the separated inner ring-shaped portion constitutes the inner ring-shaped molded part (39); including the method.

2. During the cup extrusion of the blank (3), the cup base (30) is formed between an end face (23, 123) of a first forming punch part (20, 120) and a support face (45, 145) of an ejector (41, 141). The method according to claim 1.

3. During the cup extrusion of the blank (3), at least a part of an inner peripheral surface (35') of the inner ring-shaped molded part (39) is formed by an outer peripheral surface (21, 121) of the first forming punch part (20, 120). The method according to claim 2.

4. The cup extrusion of the blank (3) is performed at a first forming station having a forming die (101) without a step, and the forming of the cup wall (31) is performed at a second forming station including a forming die (110) having a stepped region (113). The method according to any one of claims 1 to 3.

5. The cup extrusion of the blank (3) and the forming of the cup wall (31) are continuously performed at the same forming station having only one forming die (1). The method according to any one of claims 1 to 3.

6. The forming die (1) includes a stepped region (13) for forming the cup wall (31), and an inner peripheral surface (11) of the stepped region (13) of the forming die (1) is exposed by the retraction of the ejector (41) having the support face (45). The method according to any one of claims 2 to 5.

7. The cup extrusion of the blank (3) and the forming of the cup wall (31) are performed by hot forming at a temperature of 500 °C or higher. The method according to any one of claims 1 to 6. **Claim 8** A forming apparatus for manufacturing an inner ring-shaped formed part (39) and an outer ring-shaped formed part (38) from a blank (3), a first forming punch part (20, 120) for cup extrusion of the blank (3) for forming a cup (3') having an extended cup base (30), a second forming punch part (24, 124) and a forming die (1, 110) having a stepped region (13, 113) for forming the cup wall (31), wherein the cup wall (31) comprises an inner ring-shaped part (32) and an adjacent outer ring-shaped part (33) axially offset therefrom, the second forming punch part (24, 124) and the forming die (1, 110); a separating tool for separating the outer ring-shaped part (33) from the inner ring-shaped part (32) and separating the inner ring-shaped part (32) from the extended cup base (30), wherein the separated outer ring-shaped part constitutes the outer ring-shaped formed part (38), and the separated inner ring-shaped part constitutes the inner ring-shaped formed part (39); comprising a forming apparatus. **Claim 9** an ejector (41, 141) having a support surface (45, 145), comprising the first forming punch part (20, 120) comprises an end surface (23, 123) for forming the cup base (30) during cup extrusion of the blank (3). The forming apparatus according to claim 8. **Claim 10** the first forming punch part (20, 120) comprises a first peripheral outer surface (21, 121) for forming at least a part of the peripheral inner surface (35') of the inner ring-shaped formed part (39). The forming apparatus according to claim 8 or 9. **Claim 11** the ejector (41) having the support surface (45) is disposed retractably to expose the peripheral inner surface (11) of the stepped region (13) of the forming die (1) for forming the cup wall (31). The forming apparatus according to claim 9 or 10. **Claim 12** the first forming punch part (20), the second forming punch part (24), and the forming die (1) having the stepped region (13) are part of a common forming station. The method according to any one of claims 8 to 11.

13. The first forming punch part (120) and the forming die (101) without a step are part of the first forming station, and the second forming punch part (124) and the forming die (110) having the stepped region (13) are part of the second forming station. The forming device according to any one of claims 8 to 11.

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