Method for producing a pneumatic tire and tire manufacturing machine for carrying out the method

Description

[0001] The invention relates to a method for producing a pneumatic tire with a tire carcass and at least one tire bead having a core flap. The method comprises a first positioning step, comprising positioning a carcass fabric blank on a carcass drum having a drum contour. Furthermore, the method comprises a second positioning step following the first positioning step, comprising positioning the core flap on the carcass fabric blank. The method further comprises a ply turning-over step following the second positioning step, comprising turning over a turn-up portion of the carcass fabric blank around the core flap.

[0002] Furthermore, the invention relates to a tire building machine for carrying out the method for producing a pneumatic tire. The tire building machine comprises a carcass drum and a core setting device designed separately from the carcass drum, wherein the core setting device is configured to hold a core lug independently of the carcass drum and to guide the core lug toward the carcass drum in its axial direction.

[0003] The apex of a pneumatic tire fulfills several functions, such as ensuring that the tire sits securely on the rim. In a pneumatic tire manufactured using a process as described above on a tire building machine as described above, the apex of a finished pneumatic tire is embedded in the tire bead. The apex usually extends concentrically with a tire core, which is arranged radially on the inside of the circumferential apex and is embedded in the tire bead together with the apex. The apex largely determines the geometry of the tire bead and its surface, with which the pneumatic tire rests against a rim flange during use.In the finished pneumatic tire, the core vane has a stabilizing effect and increases the torsional rigidity of the pneumatic tire, which in turn benefits the driving stability and steering stability of a vehicle that is driven using the corresponding pneumatic tires.

[0004] In the method of the type mentioned above, the ply turn-over step is often carried out by expanding a turn-over bladder after the second positioning step. The turn-over bladder undergoes an outward expansion in a radial direction, whereby the turn-over bladder guides the turn-up section around the tire core and the core flap. In a further expansion with a component also in the axial direction, the turn-over bladder guides the turn-up section further around the core flap and presses the turn-up section from the outside in an axial and at least partially radial direction towards the carcass drum towards the core flap and the tire core, which in turn presses on the underlying section of the carcass fabric blank.This molds the section of the carcass fabric blank positioned on the carcass drum, the core flap arranged thereon, the tire core, and the turn-up section wrapped around the core flap and the tire core to the drum contour, thus creating the ply turn-up. This can be supported by the use of adhesives to protect the ply turn-up from unwanted deformation during further processing, especially up to vulcanization.

[0005] The disadvantage of this is that during this process of turning up the plies, the connection, particularly the bonding, between the carcass fabric blank and the core flap wrapped within it can develop weak spots due to air pockets. Likewise, the core flap can deform to a certain extent despite its initial shape. Furthermore, an incomplete bond or bonding between the carcass fabric blank and the core flap reduces the torsional rigidity of the resulting tire and reduces the driving stability, steering stability, and comfort of vehicle passengers.

[0006] JP S50 77471 U discloses a bead filler clamping device for core flags. The core flag is positioned on a carcass drum using a core setting device. The core flag is then pressed against the carcass drum by an inflatable bellows.

[0007] The object of the present invention is to improve the method and the tire building machine of the type mentioned above, in particular in order to achieve particularly stable and dimensionally stable ply turns in pneumatic tires.

[0008] According to claim 1, the object is achieved in that, in a method of the type mentioned at the outset, a shaping step is carried out after the second positioning step and before the ply turning step. During the shaping step, the core lug is pressed onto the carcass fabric blank positioned on the carcass drum by means of a shaping force from at least one fluid-actuated shaping device and is thereby shaped to the drum contour. The fluid-actuated shaping device has a first pressurizable and expandable bellows which, during the shaping step, shapes the core lug onto the carcass fabric blank with a first portion of the shaping force as pressure in the axial direction of the carcass drum, and a second pressurizable and expandable bellows which, during the shaping step, shapes the core lug onto the carcass fabric blank with a second portion of the shaping force as pressure in the radial direction of the carcass drum.

[0009] This makes it possible to exert a particularly homogeneous distribution of the forming force on the core flap and thus to exert a particularly homogeneous connection, in particular bonding, between the core flap and the carcass fabric blank positioned on the carcass drum. The connection, in particular bonding, can be effected directly between the core flap and the carcass fabric blank by contact. Alternatively, the connection, in particular bonding, can also be effected indirectly, in particular by means of a bead reinforcing element arranged between the core flap and the carcass fabric blank, for example a flipper or chipper, in particular as described later. In this sense, bonding of the core flap to the carcass fabric blank also occurs in cases in which the core flap is or will be bonded to a bead reinforcing element, which in turn is or will be bonded to the carcass fabric blank.The particularly homogeneous distribution of the forming force has the advantage that air pockets between the core flap and the carcass fabric blank, and if present, also between the bead reinforcement element and the core flap, as well as between the bead reinforcement element and the carcass fabric blank, are significantly reduced compared to processes without this separate forming step. A further advantage is that a significantly greater forming force can be applied using this additional forming step than, for example, using a folding bellows, which, as an integral process step, accomplishes the folding of the folded section and the subsequent initial compression during the ply folding step.

[0010] The additional forming step before the ply turning step also allows for a particularly good conformation of the core flap to the drum contour of the carcass drum. The pressing process ensures that the geometry of the core flap is particularly well adapted to the drum contour, achieving the desired geometry it should have as a component of the bead core with tighter dimensional tolerances than without such a separate forming step. For example, the drum contour corresponds to the contour of the drum shoulder of the carcass drum. One advantage of the process and the tire building machine is its compatibility with various different carcass drum contours, which keeps the process and the tire building machine flexible.

[0011] By means of the forming step, the forming force is transferred from a forming device to the core flap more precisely and homogeneously than if such forming only takes place as part of the ply turning-over step. In particular, the forming force is not initially exerted on a turn-up section of the carcass fabric blank that has already been turned around the core flap, from which the forming force is then further transferred to the core flap. The transfer of the forming force from a forming device to the core flap without the turn-up section of the carcass fabric blank being arranged in between thus enables particularly good adaptation to the drum contour. This gives the core flap, as a result of the forming step, a particularly precise production of the desired geometry by pressing it against the drum contour.The forming step allows those areas of the core lug that are subjected to greater deformation, particularly bending, and / or have a larger deformed cross-section to be subjected to higher pressures or bending moments than other areas of the core lug that are less deformed and / or have a smaller deformed cross-section. The forming step thus enables a particularly adequate adaptation of the stress state within the core lug for the desired forming process to the drum contour.

[0012] For this purpose, the forming device can, for example, have form-flexible elements which, for pressing the core lug, come into direct contact with the core lug or with a bead reinforcing element possibly arranged on the core lug and thus exert the forming force on the core lug.

[0013] As a result of the forming step, the core lug is pressed onto the carcass fabric blank according to the drum contour and is bonded to it in a particularly reliable and homogeneous manner, particularly by bonding. A further advantage is that this reduces the likelihood of separation of the tire components during the subsequent manufacturing process compared to processes without this forming step. This significantly increases process reliability and reduces the likelihood of rejects.

[0014] As far as the above mention is made of the positioning of the core flap on the carcass fabric blank, pressing it onto the carcass fabric blank, and molding it to the drum contour, this can, as a first alternative, concern only the core flap, or, as a second alternative, the combination of the core flap with a bead core connected to the core flap. With the first alternative, it is therefore possible that only the core flap is initially positioned and molded onto the carcass fabric blank and only then is a bead core added concentrically to the core flap. It is also possible that a bead core is initially positioned on the carcass fabric blank and then the core flap is added concentrically to the bead core.In the second alternative, in the forming step, the core flap, which is already concentrically connected to the bead core, is pressed onto the carcass fabric blank positioned on the carcass drum by means of a forming force in accordance with the aforementioned and subsequent teachings, and is thereby formed to the drum contour. The second alternative also includes possible variants of the process in which the bead core and the core flap are supplemented by at least one additional bead reinforcement element, in particular during the first positioning step and / or during the second positioning step and / or during the forming step. A flipper, i.e., an angled fabric comprising textile wrapped around the bead core and the core flap, can be added as a bead reinforcement element.It is also possible to add a chipper as a bead reinforcement element, i.e., an angled fabric made of textile and / or steel that is applied to one side of the bead core and the core flap and not wrapped around it. Of course, the use of such bead reinforcement elements is not fundamentally excluded in the first alternative, for example, in the form of a chipper being applied to the core flap and / or the bead core before the molding step.

[0015] The process for producing a pneumatic tire is then usually continued with the ply turning step, in which the turn-up section of the carcass fabric blank is placed around the core flap and the bead core and, in an additional forming step, is pressed onto the core flap, the bead core, and a portion of the carcass fabric blank. The result is a tire bead of a pneumatic tire that, due to the particularly dimensionally accurate bead core and the particularly complete connection, in particular bonding, of the tire bead components, makes a beneficial contribution to the torsional rigidity of a pneumatic tire resulting from the subsequent process step. Such a pneumatic tire exhibits particularly high driving and steering stability.

[0016] According to the invention, during the forming step, the forming force is exerted on the core flap by at least one fluid-actuated forming device. The forming force is transmitted particularly homogeneously to the core flap via one or more force-transmitting contact surfaces of the forming device. This has the advantage that, as the core flap is progressively formed onto the drum contour, the contact surfaces of the deforming core flap can be adjusted. This further improves the fixation, in particular the bonding, of the core flap to the carcass fabric blank. In cases where a bead reinforcement element, in particular a flipper or chipper, is added to the core flap and / or the bead core, the forming force is also exerted entirely or partially on this bead reinforcement element.This means that a bead reinforcement element resting on the core flap and the bead core is also formed during the forming step, corresponding to the deformation of the core flap. If such a bead reinforcement element is located between the force-transmitting contact surface(s) of the forming device and the core flap and / or the bead core during the forming step, the forming force in this area is indirectly transmitted to the core flap and / or the bead core via the bead reinforcement element.

[0017] The object is also achieved by a tire building machine according to claim 8, in which the core setting device has at least one fluid-operated forming device, by means of which a forming force can be exerted by the core setting device on a core lug that can be arranged between the carcass drum and the core setting device.

[0018] Fluid actuation means that the mechanical work required for forming is applied by introducing a liquid or gas into a fluid chamber. For example, this can be achieved using pneumatically or hydraulically expandable bodies, hydraulically or pneumatically actuated pistons, or other pneumatic or hydraulic converters.

[0019] A tire building machine with this design has the advantage that the core setting device can, on the one hand, hold a core lug in a known manner, transport it to the carcass drum, and position it on a carcass fabric blank positioned on a carcass drum. The core setting device is configured to automatically pick up a core lug, in particular together with a bead core connected to the core lug. Furthermore, the core setting device is configured to align the core lug, in particular together with a bead core connected to the core lug, concentrically with the carcass drum and, in this aligned state, to guide it in the axial direction of the carcass drum up to the carcass fabric blank positioned on the carcass drum. The core setting device is configured, for example, to hold in the region of the bead core, in particular by means of an annular gripping device.The core setting device thus holds and transports the annular bead core, around which the annular core lug connected to the bead core extends.

[0020] After the core setting device has positioned the core flap with the bead core on the carcass drum in the second positioning step of the method according to the invention and has contacted it with the carcass fabric blank located on the carcass drum, the tire building machine performs the forming step. The fluid-actuated forming device has, for example, the aforementioned flexible elements, which come into direct contact with the core flap or with a bead reinforcement element arranged on the core flap to press the core flap onto the carcass fabric blank positioned on the carcass drum and exert the forming force on the core flap. The forming device thereby presses the core flap onto the carcass fabric blank positioned on the carcass drum in such a way that the core flap adapts to the drum contour according to the method according to the invention and the core flap is connected, in particular glued, to the carcass fabric blank.

[0021] In a further development of the invention, it is provided that the at least one fluid-actuated forming device has at least one pressurizable and expandable bellows, the outer wall of which contacts the core flap and / or a bead reinforcing element arranged thereon during the forming step and exerts the forming force on the core flap, in particular by directly contacting it or indirectly via a possibly present bead reinforcing element between the core flap and the outer wall of the bellows. This has the advantage that the fluid-actuated forming device can be implemented in a simple and cost-effective manner. A further advantage is that a pressurizable and expandable bellows adapts particularly well to the contour of the core flap, which changes during the forming process, and optionally to that of a bead reinforcing element resting against the core flap.A further advantage is that the shape flexibility of such a bellows allows, within certain limits, the pressing and forming of core flaps with different geometries without the need to adapt the forming device due to even minor differences in the geometries of the various core flaps. This makes the process variable for different tire types and types of core flaps. The hydrostatic fluid pressure of the actuating fluid is applied to the inner walls of at least one bellows. The hydrostatic fluid pressure is transmitted through the wall of the bellows to the outer wall of the bellows and from there to the contacted core flap.

[0022] In a further development of the invention, it is provided that the fluid-actuated molding device, in particular an expandable bellows, has a first pressing surface extending concentrically to the core flap during the molding step, in particular an annular pressing surface. This has the advantage that the molding force can be transmitted or is transmitted to the annular core flap in a particularly evenly distributed manner. During the molding step, the pressing surface lies on the side of the core flap facing away from the carcass fabric blank and / or the side of a bead reinforcing element facing away from the carcass fabric blank and thereby transmits the molding force to the core flap. The pressing surface is thus a possible variant of an outer wall of the at least one bellows.

[0023] According to the invention, during the forming step, a first pressurizable and expandable bellows forms the core flap onto the carcass fabric blank with a first portion of the forming force as pressure in the axial direction of the carcass drum. For this purpose, the forming device of the tire building machine has the first pressurizable and expandable bellows, which is configured to exert the pressure in the axial direction of the carcass drum. During the forming step, the first bellows consequently expands in the axial direction and is configured to press the core flap particularly effectively onto the carcass fabric blank on the carcass drum in those regions in which the contact surface of the core flap on the carcass fabric blank is oriented at right angles or nearly at right angles with respect to the axial direction of the carcass drum.

[0024] According to the invention, a second pressurizable and expandable bellows is provided, which forms the core flap onto the carcass fabric blank with a second portion of the forming force as pressure in the radial direction of the carcass drum. For this purpose, the forming device of the tire building machine has the second pressurizable and expandable bellows, which is configured to exert the pressure in the axial direction of the carcass drum. During the forming step, the second bellows consequently expands in the radial direction and is configured to press the core flap particularly effectively onto the carcass fabric blank on the carcass drum in those areas in which the contact surface of the core flap on the carcass fabric blank is oriented parallel or nearly parallel with respect to the axial direction of the carcass drum.

[0025] In a further development of the invention, a third pressurizable and expandable bellows is provided, which forms the core flap onto the carcass fabric blank with a third portion of the forming force as pressure in the axial direction and in the radial direction of the carcass drum. For this purpose, the forming device of the tire building machine has the third pressurizable and expandable bellows, which is configured to exert pressure in the axial direction and in the radial direction of the carcass drum. During the forming step, the third bellows consequently expands in a superimposed direction of the axial direction and the radial direction of the carcass drum and is configured to press the core flap particularly effectively onto the carcass fabric blank on the carcass drum in those areas in which the contact surface of the core flap on the carcass fabric blank is oriented obliquely with respect to both the axial direction and the radial direction of the carcass drum.

[0026] In a further development of the method according to the invention, it is provided that in the second positioning step, one or the aforementioned core setting device of a tire building machine carries out the positioning of the core flap, wherein the core setting device holds the core flap and moves it towards the carcass fabric blank in the axial direction of the carcass drum until, in a contact position of the core setting device, the core flap and the carcass fabric blank touch each other. In cases in which a bead reinforcing element is arranged on the core flap on the side facing the carcass drum, in particular a section of a flipper, this bead reinforcing element can also touch the carcass fabric blank in the contact position. During the forming step, the forming force is then exerted on the core flap by the core setting device.In this sense, the core setting device accomplishes both the positioning of the core lug of the second positioning step, as well as the pressing and forming of the forming step. The fact that the tire building machine is equipped to carry out these steps has the advantage that the forming step can be integrated into a process previously carried out without such a forming step with almost or completely neutral cycle time. Thus, existing process procedures can be supplemented with the forming step according to the invention with little or no impact on process logistics. With regard to the tire building machine, this has the corresponding advantage that only the core setting device needs to be supplemented with a forming device.With the addition of such a molding device, the molding step according to the invention can be carried out with a tire building machine of the type mentioned above immediately after positioning the core flap on the carcass fabric blank according to the second positioning step. Thus, existing production systems can also be supplemented in a simple and cost-effective manner according to the invention.

[0027] According to a further development of the invention, the core setting device is arranged in the contact position during the forming step. This has the advantage that the core setting device does not perform any additional travel movements for the forming step. In particular, the forming step can be integrated into existing processes that were originally designed without the forming step with virtually no cycle time impact. A further advantage is that, in the contact position, the core lug remains effectively secured against slipping relative to the carcass fabric blank by means of the core setting device during the forming step. This increases process reliability.

[0028] According to a further development of the invention, the core setting device has a magnetic ring with which it holds the core flap during the second positioning step, in particular by magnetically attracting a bead core connected to the core flap. The magnetic ring serves as a gripping device for holding and positioning the bead core and a core flap connected to the bead core, as well as optionally a bead reinforcement element connected to the core flap and / or the bead core. In the method according to the invention, this has the advantage that, after the forming step, the core setting device is axially reset from the carcass drum in such a way that the bellows or bellows eject the bead core against the magnetic force. In this respect, the bellows or bellows can act as an ejection device for the bead core against the magnetic force.

[0029] Further embodiments of the invention can be found in the dependent claims and in the following exemplary embodiment, which explains a possible variant of the invention in more detail. The drawings show Fig. 1: a core setting device in a first position in front of a carcass drum in cross-sectional view, Fig. 2: the core setting device in a contact position in front of the carcass drum in cross-sectional view before a forming step; Fig. 3: the core setting device and carcass drum according to Fig. 2 after a forming step.

[0030] Figure 1shows a cross-sectional view of a part (shown broken away along the jagged line) of a carcass drum 2 and a core setting device 4. The carcass drum 2 extends rotationally symmetrically around its drum axis 6. The carcass drum 2 has a circumferential surface 8 on which the carcass drum 2 is covered with a carcass fabric blank 10. The carcass fabric blank 10 is arranged in one piece or in multiple pieces with one or more layers completely circumferentially on the circumferential surface 8. The carcass drum 2 with the carcass fabric blank 10 according to this illustration results from a first positioning step according to the invention, in which the carcass fabric blank 10 was positioned on the carcass drum 2. The carcass drum 2 has a drum contour 8, 12, 14, which comprises the lateral surface 8, an axial surface 12 and a drum shoulder 14 of the carcass drum 2.The carcass fabric blank 10 extends laterally from the lateral surface 8 over the drum shoulder 14 to the axial surface 12. At the axial surface, the carcass fabric blank 10 ends with a turn-up section 16. In the area of the drum shoulder 14 and the axial surface 12, the carcass fabric blank 10 also extends rotationally symmetrically around the drum axis 6.

[0031] In this representation according to Figure 1 the carcass drum 2 with the carcass fabric blank 10 is prepared so that a bead core 18 with a core lug 20 attached to it is positioned in the area of the drum shoulder 14 on the carcass fabric blank 10 and pressed against it.

[0032] In the method, the core lug 20 is positioned together with the bead core 18 in a second positioning step following the first positioning step. The second positioning step of the method is carried out by means of the core setting device 4. The core setting device 4 is designed to be rotationally symmetrical about its axis 22. During the second positioning step, the core setting device 4 holds the core lug 20 together with the bead core 18. The core setting device 4 holds the core lug 20 with the bead core 18 by means of a gripping device 24 in the form of a magnetic ring 24. The direct gripping is achieved by the magnetic interaction of the magnetic ring 24 with the metal-containing bead core 18. During positioning according to the second positioning step, the core setting device 4, which is itself moved, moves the bead core 18 with the core lug 20 towards the carcass drum 2.In such a tire building machine 26, which has the carcass drum 2 and the core setting device 4, the movement of the core setting device 4 toward the carcass drum 2 occurs, for example, automatically by means of actuators. This positioning of the core lug 20 and the bead core 18 on the carcass fabric blank 10 is achieved by an axial movement of the core setting device 4 in the direction of its axis 22 and in the axial direction 28 of the drum axis 6. During the second positioning step, the drum axis 6 and the axis 22 of the core setting device are aligned with one another, so that the core setting device 4 and the carcass drum 2 are arranged concentrically with one another. In the positioning step, the contact surface 30 of the bead core 18 and the contact surface 32 of the core flap 20 are coated with an adhesive by means of which the bead core 18 and the core flap 20 adhere to the carcass fabric blank 10 after the second positioning step.

[0033] In the second positioning step, the core setting device 4 moves from the position shown in Figure 1 illustrated arrangement in the axial direction 28 up to the carcass drum 2, so that in a contact position the bead core 18 comes to rest with its contact surface 30 in the region of the drum shoulder 14 and / or the axial surface 20 on the carcass fabric blank 10. Depending on the shape of the core flap 20, in this contact position a part of the contact surface 32 of the core flap 20 can also already come to rest on the carcass fabric blank 10. In the contact position the core setting device 4 holds the contact surface 30 of the bead core 18 and optionally a part of the contact surface 32 of the core flap 20 fixed by means of a positioning force acting in the axial direction 28. This prevents slipping of the bead core 18 and the core flap 20 with respect to the carcass fabric blank 10.

[0034] Figure 2shows the carcass drum and the core setting device 4 in the contact position, as they are arranged after completion of the second positioning step. Here, part of the contact surface 32 of the core lug 20 or the entire contact surface 32 of the core lug 20 is still arranged at a distance from the carcass fabric blank 10 in the region of the drum shoulder 14. After the second positioning step, a molding step is carried out according to the invention, in which the core lug 20 is pressed against the carcass blank 10 by means of a molding force and is thereby molded onto the drum contour 8, 12, 14, particularly in the region of the drum shoulder 14. This is done while maintaining the contact position of the core setting device 4. The shaping of the core lug 20 to the drum contour 8, 12, 14 comprises reshaping the core lug 20 such that the contour of the contact surface 32 of the core lug 20 is adapted to the drum contour 8, 12, 14.This occurs by pressing the contact surface 32 of the core flap 20 against the carcass fabric blank 10, which in turn follows the drum contour 8, 12, 14. During the forming step, the turn-up section 16 has not yet been folded over around the bead core 18 and the core flap 20 by means of a layer-turning step. Rather, the pressing and thus the forming of the core flap during the forming step takes place through the direct action of the forming force applied for this purpose on the surface 34 on the side of the core flap 20 that is oriented away from the carcass fabric blank 10.

[0035] The core setting device 4 of the tire building machine 26 has a fluid-actuated forming device 36 for applying the forming force. The forming device 36 has a first expandable bellows 38, which can be filled with a fluid from the inside and thus subjected to pressure. The fluid can be, for example, air, water, oil, or another fluid. Furthermore, the forming device 36 has a second expandable bellows 40, which can be filled with a fluid from the inside and thus subjected to pressure. The forming device 36 further comprises at least one pressure generator (not shown) which can convey the respective fluid into the first bellows 38 and / or into the second bellows 40 and in the process generate the pressure acting in the respective bellows 38, 40.

[0036] During the molding step, the first bellows 38 and the second bellows 40 are filled with fluid, thereby generating a pressure in each case. The first bellows 38 and the second bellows 40 expand and thereby press the core flap 20, starting from the core setting device 4, against the carcass fabric blank 10 arranged on the carcass drum 2 with a molding force. Due to the pressing, the core flap 20 is subjected to bending, particularly along its radial extent, so that the core flap 20 is molded to the drum contour 8, 12, 14. As a result of the forming step, the core lug 20 lies evenly on the carcass fabric blank 10, whereby by pressing and forming by means of the first bellows 38 and the second bellows 40, a particularly reliable bond is achieved between the core lug 20 and the carcass fabric blank 10 while simultaneously adapting the core lug 20 to the drum contour 8, 12, 14.

[0037] The first bellows 38 and the second bellows 40 extend rotationally symmetrically around the axis 22 of the core setting device 4. The first bellows 38 has a first pressure surface 42 as an outer wall. During the forming step, the first pressure surface 42 thus also extends concentrically to the core setting device 4 and to the core lug 20. During the forming step, the first pressure surface 42 is annular and is directed in the axial direction 28 toward the core lug 20 and the carcass drum 2. During the expansion of the first bellows 38, it exerts a first portion of the forming force as pressure in the axial direction 28 onto the core lug 20 by means of the first pressure surface 42, which deforms in the process.

[0038] The second bellows 40 has a second pressure surface 44 as an outer wall. During the molding step, the second pressure surface 44 also extends concentrically to the core setting device 4 and to the core lug 20. During the molding step, the second pressure surface 44 has the shape of a cylindrical wall before expansion and is directed inward in the radial direction 46 toward the core lug 20 and the carcass drum 2. During the expansion of the second bellows 38, it exerts a second portion of the molding force as pressure in the radial direction 46 onto the core lug 20 by means of the second pressure surface 44, which is deformed in the process.

[0039] During the expansion of the bellows in the forming step, the first pressing surface 42 and the second pressing surface 44 form themselves against the surface 34 of the core flap 20 facing away from the carcass fabric blank 10 and thus bring about a uniform surface compression between the contact surface 32 of the core flap 20 and the carcass fabric blank 10.

[0040] This state of the expanded bellows 38, 40 formed onto the core lug 20 at the end of the forming step is shown in Figure 3shown. With the core flap 20 pressed completely and flatly against the carcass fabric blank 10, the carcass fabric blank 10, the bead core 18, and the core flap 20 are prepared for a subsequent ply turning step. To carry out the ply turning step, the core setting device 2 is retracted in the opposite axial direction 28 from the carcass drum 2. The glued bead core 18 and the glued core flap 20 remain on the carcass fabric blank 10, which in turn follows the drum contour 8, 12, 14. The fact that the bead core 18 and the core flap 20 are released from the core setting device 4 against the magnetic force can be assisted by further expanding the bellows 38, 40 during the retraction of the core setting device 4. In this respect, the bellows 38, 40 also have the function of a release device.

[0041] Subsequently, in the ply turning step following the forming step, the turn-up section 16 of the carcass fabric blank 10 is placed around the bead core 18 and the core flap 20 and bonded by pressing to form a ply turn-up. Thus, at the end of the ply turning step, the turn-up section 16 comes to rest on the surface 34 of the core flap 20 facing away from the carcass drum 2.

[0042] The carcass fabric blank 10 with the thus created ply turn-up is now ready for further shaping of the tire carcass and for further processing steps to complete a pneumatic tire. This may include, for example, the application of an airtight inner layer, the attachment of sidewall components, the application of steel belts, and the application of a tread.

[0043] The above teaching is presented regarding a method for producing a (single) tire bead. For those skilled in the art, the production of a pneumatic tire typically involves performing the method twice simultaneously (not specifically described). For this purpose, the carcass drum 2, in addition to the aforementioned and illustrated first drum contour 8, 12, 14, also has a further drum contour at a second axial end of the carcass drum 2, on which the method according to the invention is carried out accordingly by means of a second core setting device. List of reference symbols

[0044] 2Carcass drum 4Core setting device 6Drum axis 8Shell surface 10Carcass fabric blank 12Axial surface 14Drum shoulder 16Turn-over section 18Bead core 20Core vane 22Axle 24Magnet ring 26Tire building machine 28Axial direction 30Contact surface 32Contact surface 34Surface 36Forming device 38First bellows 40Second bellows 42First pressure surface 44Second pressure surface 46Radial direction

Claims

1. Method for producing a pneumatic tyre with a tyre carcass and at least one tyre bead having a flipper strip, comprising the following method steps: - a first positioning step, comprising positioning a carcass fabric blank (10) on a carcass drum (2) having a drum contour (8, 12, 14), - a second positioning step, following the first positioning step and comprising positioning the flipper strip (20) on the carcass fabric blank (2), - a ply turning-up step, following the second positioning step and comprising turning up a turn-up portion (16) of the carcass fabric blank (10) around the flipper strip (20), wherein, after the second positioning step and before the ply turning-up step, a forming step is carried out, in which the flipper strip (20) is pressed by means of a forming force of at least one fluidically actuable forming device (36, 38, 40) against the carcass fabric blank (10) positioned on the carcass drum (2), and is thereby formed to the shape of the drum contour (8, 12, 14), characterized in that the fluidically actuable forming device (36, 38, 40) has a first pressurizable and expandable bladder (3), which in the forming step forms the flipper strip (20) onto the carcass fabric blank (10) with a first component of the forming force as pressure in the axial direction (28) of the carcass drum (2), and has a second pressurizable and expandable bladder (40), which in the forming step forms the flipper strip (20) onto the carcass fabric blank (10) with a second component of the forming force as pressure in the radial direction (46) of the carcass drum (2).

2. Method according to Claim 1, characterized in that the at least one fluidically actuable forming device (36, 38, 40) has at least one pressurizable and expandable bladder (38, 40), the outer wall (42, 44) of which in the forming step contacts the flipper strip (20) and / or a bead reinforcement element arranged thereon and exerts the forming force on the flipper strip (20).

3. Method according to one of the preceding claims, characterized in that the fluidically actuable forming device (36, 38), in particular a or the expandable bladder (38), has in the forming step a first pressing area (42), extending concentrically in relation to the flipper strip, in particular an annular pressing area (42).

4. Method according to one of the preceding claims, characterized in that in the forming step a third pressurizable and expandable bladder forms the flipper strip (20) onto the carcass fabric blank (10) with a third component of the forming force as pressure in the axial direction (28) and in the radial direction (46) of the carcass drum (2).

5. Method according to one of the preceding claims, characterized in that - in the second positioning step a core setting device (4) of a tyre building machine (2, 4, 26) carries out the positioning of the flipper strip (20), wherein the core setting device (4) holds the flipper strip and brings it up to the carcass fabric blank (10) in the axial direction (28) of the carcass drum (2), until the flipper strip (20) and the carcass fabric blank (10) contact one another and / or a bead reinforcement element arranged on the flipper strip (20) and the carcass fabric blank (10) contact one another in a contact position of the core setting device (2), and in that - in the forming step the forming force is exerted by the core setting device (4) on the flipper strip (20).

6. Method according to Claim 5, characterized in that in the forming step the core setting device (4) is arranged in the contact position.

7. Method according to one of Claims 5 or 6, characterized in that the core setting device (4) has a magnetic ring (24), with which it holds the flipper strip (20) in the second positioning step, in particular by magnetically attracting a bead core (18) connected to the flipper strip (20).

8. Tyre building machine for carrying out the method for producing a pneumatic tyre according to one of the preceding claims, having a carcass drum (2) and a core setting device (4), formed separately from the carcass drum (2), wherein the core setting device (4) is designed for holding a flipper strip (20) independently of the carcass drum (2) and for bringing the flipper strip (20) up to the carcass drum (20) in the axial direction (28) thereof, wherein the core setting device (2) has at least one fluidically actuated forming device (36, 38, 40), by means of which a forming force can be exerted by the core setting device (4) on a flipper strip (20) that can be arranged between the carcass drum (2) and the core setting device (4), characterized in that the fluidically actuable forming device (36, 38, 40) has a first pressurizable and expandable bladder (38), which is designed for exerting a pressure in the axial direction (28) of the carcass drum (2), and a second pressurizable and expandable bladder (40), which is designed for exerting a pressure in the radial direction (46) of the carcass drum (2).

9. Tyre building machine according to Claim 8, characterized in that the at least one fluidically actuable forming device (36, 38, 40) has at least one pressurizable and expandable bladder (38, 40), the outer wall (42, 44) of which is designed for exerting the forming force on the flipper strip (20) that can be arranged between the carcass drum (2) and the core setting device (4).

10. Tyre building machine according to Claim 9, characterized in that the forming device (36, 38, 40) has a third pressurizable and expandable bladder, which is designed for exerting a pressure in the axial direction (28) and in the radial direction (46) of the carcass drum (2).

11. Tyre building machine according to one of Claims 8 to 10, characterized in that the core setting device (4) has a magnetic ring (24), which is designed for holding a flipper strip (20), in particular by magnetically attracting a bead core (18) connected to the flipper strip (20).