Patent Application
20130341827
The invention relates to a bead core-apex subassembly as it may be used as a pre-assembled component in the manufacturing of a pneumatic tire. More particularly, it relates to an apparatus for manufacturing such an annular bead core-apex subassembly and a method of manufacturing such an annular bead core-apex subassembly.
EP 1 123 198 B1 describes a bead core-apex subassembly and a tire comprising such an assembly. The apex filler is produced from an extruded strip of elastomeric material.
EP 1 165 306 B1 describes a combined bead loading and apex application system. A bead core-apex subassembly is manufactured, transferred onto a building drum and employed into a pneumatic tire.
US Patent Publication 2011/0146884 describes the mixing of rubber compounds for use in tire manufacturing and a method of applying a blended rubber composition on a substrate such as a tire building drum or a core.
US Patent Publication 2011/0146888 describes again the mixing of rubber compounds for use in tire manufacturing. It describes also a method of forming a rubber article comprising two or more layers, the method comprising the steps of extruding a first rubber compound through a first extruder and a first gear pump, applying one or more first strips of rubber of the mixture directly onto a substrate, mixing a second rubber compound, and applying one or more second strips of rubber of the second mixture. The rubber article may be an apex of a pneumatic tire, the apex comprising two or more layers of rubber.
US Patent Publication 2004/0089400 describes a method and apparatus for forming an annular elastomeric tire component. An elastomer is extruded annularly onto a support surface and a strip of the elastomer material is shaped to a predetermined profile between a shaping die and the support surface. The method may be used to form multilayered components.
U.S. Pat. No. 7,501,033 describes a method of manufacturing a bead core-apex-chipper subassembly for use in a pneumatic tire. A continuous elastomeric strip is extruded on a support surface as an apex strip, a chipper ply strip is attached to the apex strip, and the chipper and apex subassembly is attached to an annular bead core.
EP 1 749 648 A2 describes a method and apparatus for applying a strip of elastomeric component to a surface. An apex may be shaped having a tip and a portion opposite the tip which is attached to a bead core. The apparatus comprises a nozzle in fluid communication with a pumping means and a shaping die. A tongue is rotatably mounted adjacent the nozzle to compress an elastomeric material applied through the nozzle as a strip onto a surface against said surface.
A challenge has been presented to provide an improved method of manufacturing a bead core-apex subassembly which may be automated and which is less labor and/or energy intensive than existing apexing processes. The method should also not negatively affect uniformity of a pneumatic tire comprising such a bead core-apex subassembly and even help to improve tire uniformity. At the same time, the method should not require the use of solvent based cements. A challenge has also been presented to provide an apparatus to implement such a method.
A further challenge has been presented to provide a method of manufacturing a pneumatic tire requiring fewer manufacturing steps in terms of incorporating a bead core and apex and, if appropriate, a flipper, in the pneumatic tire.
A further challenge has been presented to provide a method and an apparatus which allows for manufacturing tires with smaller apexes to reduce tire weight.
A further challenge has been presented to provide an improved bead core-apex subassembly which may be manufactured using this method and which may be easily adapted in its physical characteristics to specific tire performance requirements such as handling performance, durability performance and, if applicable, run-flat performance.
In an example of the invention, an apparatus for manufacturing an annular bead core-apex subassembly is provided, the apparatus comprising a first station at a first location having a first support surface and a second station at a second location having a second support surface, wherein the first support surface is mounted to a first support element and is rotatable on the first support element about an axis extending perpendicular to the first support surface, wherein the second support surface is mounted to a second support element and is rotatable on the second support element about an axis extending perpendicular to the second support surface, wherein the apparatus comprises a moving device configured for moving the first support surface from the first location to the second location and for moving the second support surface from the second location to either the first location or to a further location, wherein the apparatus comprises at least one handling device selected from the group consisting of (i) a loading device for positioning an annular bead core on the respective support surface at the first location, and (ii) an unloading device for removing an annular bead core-apex subassembly from the respective support surface at the first location, and wherein the apparatus comprises a first nozzle in fluid communication with a first pumping or extrusion device for discharging a first rubber compound onto a respective support surface at the second location.
In yet another example aspect of the invention, the apparatus further comprises a third station at a third location having a third support surface, wherein the third support surface is mounted to a third support element and is rotatable on the third support element about an axis extending perpendicular to the third support surface, wherein the moving device is configured for moving the first support surface from the first location to the second location, for moving the second support surface from the second location to the third location, and for either moving the third support surface from the third location to the first location or to a further location, wherein the handling device is a loading device for positioning an annular bead core on the respective support surface at the first location, and wherein the apparatus further comprises an unloading device for removing an annular bead core-apex subassembly from a respective support surface at the third location.
In still another example aspect of the invention, the apparatus comprises a third station at a third location having a third support surface, wherein the third support surface is mounted to a third support element and is rotatable on the third support element about an axis extending perpendicular to the third support surface, wherein the moving device is configured for moving the first support surface from the first location to the second location, for moving the second support surface from the second location to the third location, and for either moving the third support surface from the third location to the first location or to a further location, and wherein the apparatus comprises a second nozzle in fluid communication with a pumping or extrusion device for discharging a second rubber compound onto a respective support surface at the third location.
In yet another example aspect of the invention, the apparatus comprises a third station at a third location having a third support surface, wherein the third support surface is mounted to a third support element and is rotatable on the third support element about an axis extending perpendicular to the third support surface, wherein the apparatus further comprises a fourth station at a fourth location having a fourth support surface, wherein the fourth support surface is mounted to a fourth support element and is rotatable on the fourth support element about an axis extending perpendicular to the fourth support surface, wherein the moving device is configured for moving the first support surface from the first location to the second location, for moving the second support surface from the second location to the third location, for moving the third support surface from the third location to the fourth location, and for either moving the fourth support surface to the first location or to a further location, wherein the handling device is a loading device for positioning an annular bead core on a respective support surface at the first location, wherein the apparatus comprises an unloading device for removing an annular bead core-apex subassembly from a respective support surface at the fourth location, and wherein the apparatus comprises a second nozzle in fluid communication with a second pumping or extrusion device for discharging a second rubber compound onto a respective support surface at the third location.
In still another example aspect of the invention, the first and the second support surface is each a flat, disc-shaped support surface.
In yet another example aspect of the invention, the first support element is a first arm extending from a center, wherein the second support element is a second arm extending from said center, and wherein the first and second support element are rotatable about said center.
In still another example aspect of the invention, the first, second and third support surface is each a flat, disc-shaped support surface, wherein the first support element is a first arm extending from a center, wherein the second support element is a second arm extending from said center, wherein the third support element is a third arm extending from said center, and wherein the first, second and third support element are rotatable about said center.
In yet another example aspect of the invention, the first, second and third support surface is each a flat, disc-shaped support surface, wherein the first support element is a first arm extending from a center, wherein the second support element is a second arm extending from said center, wherein the third support element is a third arm extending from said center, and wherein the first, second and third support element are rotatable about said center.
In still another example aspect of the invention, the first, second, third and fourth support surface is each a flat, disc-shaped support surface, wherein the first support element is a first arm extending from a center, wherein the second support element is a second arm extending from said center, wherein the third support element is a third arm extending from said center, wherein the fourth support element is a fourth arm extending from said center, and wherein the first, second, third and fourth support element are rotatable about said center.
In yet another example aspect of the invention, the first, second, third and fourth arm are arranged about the center at an angular distance of substantially 90 degrees and wherein the first, second, third and fourth arm have a substantially equal length.
In still another example aspect of the invention, the first and second arm are arranged about the center at an angular distance of substantially 180 degrees and wherein the first and second arm have a substantially equal length.
In yet another example aspect of the invention, the first, second and third arm are arranged about the center at an angular distance of substantially 120 degrees and wherein the first, second and third arm have a substantially equal length.
In still another example aspect of the invention, the first, second and third arm are arranged about the center at an angular distance of substantially 120 degrees and wherein the first, second and third arm have a substantially equal length.
In yet another example aspect of the invention, the loading device is configured for holding a spacer disc on which an annular bead core is located and for moving this spacer disc with the annular bead core to the first support surface thereby positioning the annular bead core on the first support surface.
In still another example aspect of the invention, the unloading device is configured for holding a spacer disc on which a bead core-apex subassembly is located and for removing this spacer disc with the bead core-apex subassembly from the first support surface.
In yet another example aspect of the invention, the first pumping or extrusion device comprises a first gear pump.
In still another example aspect of the invention, the first pumping or extrusion device comprises a first gear pump and the second pumping or extrusion device comprises a second gear pump.
In yet another example aspect of the invention, the first nozzle is configured to provide the first rubber compound in the shape of a strip.
In still another example aspect of the invention, the first nozzle is configured to provide the first rubber compound in the shape of a strip and the second nozzle is configured to provide the first rubber compound in the shape of a strip.
In yet another example aspect of the invention, the first nozzle comprises a shaping element for bringing the discharged first rubber compound into a substantially triangular shape.
In still another example aspect of the invention, the second nozzle comprises a shaping element for bringing the discharged second rubber compound or the combination of the discharged first and second rubber compound into a substantially triangular shape.
In yet another example aspect of the invention, the first nozzle is moveable in a radial direction with respect to the annular bead core at the second station.
In still another example aspect of the invention, the second nozzle is moveable in a radial direction with respect to the annular bead core at the third station.
In yet another example aspect of the invention, the support surface comprises a stop or a clamping device for positioning or holding the bead core on the support surface.
In still another example aspect of the invention, a method of manufacturing an annular bead core-apex subassembly is provided. The method comprises: positioning an annular bead core on a support surface at a first station; moving the support surface with the annular bead core to a second station; rotating the support surface with the annular bead core at the second station about an axis extending perpendicular to the first support surface; discharging a first rubber compound onto the rotating support surface at the second station; establishing the annular bead core-apex subassembly; moving the support surface with the annular bead core-apex subassembly to a further station; and removing the annular bead core-apex subassembly from the support surface at the further station.
In yet another example aspect of the invention, the further station is the first station.
In still another example aspect of the invention, the method comprises: after discharging the first rubber compound onto the rotating support surface at the second station, moving the support surface with the discharged first rubber compound to a third station; rotating the support surface with the annular bead core at the third station about an axis extending perpendicular to the first support surface; and discharging a second rubber compound onto the rotating support surface at the third station.
In yet another example aspect of the invention, the further station is an unloading station different from the first station.
In still another example aspect of the invention, the annular bead core is positioned on a spacer disc and the annular bead core on the spacer disc is positioned on the support surface at the first station.
In yet another example aspect of the invention, the annular bead core-apex subassembly is established on the spacer disc and removed from the support surface at the further station together with the spacer disc.
The invention may be used to manufacture a bead core-apex subassembly comprising an annular bead core, a flipper and an apex, wherein the flipper is wrapped about the bead core such that it encloses the bead core, and wherein the apex is in contact with the flipper. In one example, the apex may comprise a first segment and a second segment, the first segment having a composition different from the composition of the second segment.
The bead core may be a conventional bead core and may comprise, for instance, one or more steel wires. The flipper may be a conventional flipper as used in tire manufacturing. It may be a fabric or a reinforced rubber ply. The apex may have a substantially triangular shape and extends from the flipper to an apex tip.
If the apex has a first and a second segment, at least one of the cross-section of the first segment and the cross-section of the second segment may have a substantially triangular shape. In this case, only the first segment of the apex may be in contact with the flipper. In this case, the first segment comprises a first rubber composition and the second segment comprises a second rubber composition wherein the shore A hardness of the first rubber composition may differ by at least 3, alternatively by at least 5 or at least 10, from the shore A hardness of the second rubber composition and/or wherein the shore A hardness of the first segment may be larger, by at least 3 larger, than the shore A hardness of the second segment.
The invention may also be used to practice a method of manufacturing a bead core-apex subassembly, the method comprising the steps of providing an annular bead core; wrapping a flipper about the annular bead core such that the flipper encloses the bead core; positioning the bead core with the flipper wrapped about the bead core on a rotatable support surface; providing a nozzle in fluid communication with a pumping or extrusion device; rotating the support surface about an axis; and discharging a rubber compound through the nozzle onto the rotating support surface and forming an apex from the discharged rubber compound, the apex being attached to the flipper. In this method, the apex may be shaped into a substantially triangular shape while or after discharging the rubber compound onto the rotating support surface, the apex extending from a base to a tip, the base being attached to the flipper. The pumping or extrusion device may comprise a gear pump. The nozzle may comprise a tongue, the tongue compressing the rubber compound against at least one of the rotating support surface and the bead core with the flipper wrapped about the bead core. The rotatable support surface rotates by substantially 360 degrees or more during discharge of the rubber compound. The rubber compound may be discharged substantially in the shape of a strip onto the rotating support surface. The nozzle may be moved radially relative to the annular bead core located on the support surface while discharging the strip rubber compound. Hence, the apex may be formed from one or more rubber strips discharged through one or more nozzles onto the rotating support surface.
In still another example aspect of the invention, the support surface rotates horizontally and the axis of rotation is perpendicular to the support surface.
“Bead Core” generally means one or more annular tensile members that are associated with holding the tire to the rim. Often, the bead core is made from one or more steel wires wound to the bead core. The bead core may have various cross-sections such as round or hexagonal.
“Apex” or the equivalent term “bead filler apex” means an elastomeric filler structure which is located radially above the bead core and between the plies in a pneumatic tire.
“Flipper” refers to a reinforcing fabric for placing about the bead core for strength and to tie the bead core in the tire body. It may be a fabric or a reinforced rubber ply.
The invention will be described by way of example and with reference to the accompanying drawings in which:
The support surface 10 may include a stop or clamping device 13 which serves to allow a precise positioning of the bead core 20 on the support surface 10, and optionally also to clamp the bead core 20 on the support surface 10. The shape of the stop 13 in the contact with the bead core 20 with the flipper 21 wrapped around the bead core 20 may be adapted to the shape of the bead core 20 to provide a kind of stop having a complementary shape to the shape of the bead core 20 with the flipper 21.
After the bead core 20 with the flipper 21 has been put on the support surface 10, either with the spacer 11 or without the spacer 11, an elastomeric material 22 is discharged through a nozzle 51 on the support surface 10 or, if applicable, on the spacer 11 to form an apex 23 from the discharged rubber compound attached to the flipper 21 and, via the flipper 21, to the bead core 20. The rubber compound may be discharged in the form of a strip as indicated in
The first segment 32 and the second segment 32′ may both have a substantially triangular shape with the second segment 32′ forming the tip 40 of the apex 33 and the first segment 32 forming the base 41 of the apex 33 or at least substantially the base 41 of the apex 32 and being in contact with the flipper 21 and thereby with the annular bead core 20.
In order to establish the first and second segments 32, 32′, the apparatus 50 shown in
The flipper 21 in the above described first or second example may be a flipper made from a conventional flipper material as commonly used in tire manufacturing, i.e., a fabric or a reinforced rubber ply for instance.
The first rubber composition used in the second example and the second rubber composition used in the second example may differ in their shore A hardness. In one example, the difference in shore A hardness is at least 3, alternatively at least 5 or at least 10. In another example, the shore A hardness of the first segment is larger, by at least 3 larger than the shore A hardness of the second segment.
The discharge of the elastomeric material(s) for establishing the apex 23 or the first and second segments 32, 32′ of the apex 33 is done while the rotatable support 10 is rotated by substantially 360 degrees or by an integer multiple of 360 degrees. During rotation of the support 10 the nozzle 51 is moved radially relative to the annular bead core 20 located on the support surface 10 while discharging the rubber material so that the strips are positioned on the support surface or the spacer 11 as shown in
In alternative examples to
In yet further alternative examples to
In one example, the apparatus 100 comprises at least a first station 71 at a first location having a first support surface and a second station 72 at a second location having a second support surface. The first support surface is mounted to a first support element and is rotatable on the first support element about an axis extending perpendicular to the first support surface. The second support surface is mounted to a second support element and is rotatable on the second support element about an axis extending perpendicular to the second support surface. The apparatus 100 further comprises a moving device configured for moving the first support surface from the first location to the second location and for moving the second support surface from the second location to either the first location or to a further location. The apparatus 100 further comprises at least one handling device selected from the group consisting of (i) a loading device for positioning the annular bead core 20 on the respective support surface at the first location, and (ii) an unloading device for removing the annular bead core-apex subassembly 5 from the respective support surface at the first location. The apparatus 100 also comprises at least a first nozzle 51 in fluid communication with a first pumping or extrusion device 50 for discharging a first rubber compound onto a respective support surface at the second location.
In the example shown in
In the example shown in
In the example shown in
In case the apparatus 100 comprises only the first and second station 71, 72 but not the third and fourth station 73, 70, the first and second arm 61, 62 may be arranged about the center 60 at an angular distance of substantially 180 degrees. Alternatively, in case the apparatus 100 comprises four stations, 70, 71, 72, 73, the stations may be arranged in a linear configuration.
In case the apparatus 100 comprises only the first, second and third station 71, 72, 73 but not the fourth station 70, the first, second and third arm 61, 62, 63 may be arranged about the center 60 at an angular distance of substantially 120 degrees.
The loading device of the apparatus 100 may be configured for holding the spacer disc 11 on which the annular bead core 20 is located and for moving this spacer disc 11 together with the annular bead core 20 to the first support surface, thereby positioning the annular bead core 20 on the first support surface.
The unloading device of the apparatus 100 may be configured for holding the spacer disc 11 on which a finished bead core-apex subassembly 5 is located and for removing this spacer disc 11 together with the bead core-apex subassembly 5 from the first support surface.
One or both of the first and second pumping or extrusion devices may comprise a gear pump.
In one example, one or both of the first and second nozzles 51 is configured to provide a rubber compound in the shape of a strip. Alternatively, one or both of the first and second nozzles 51 may comprise a shaping element for bringing the discharged rubber compound into a substantially triangular shape.
The first nozzle 51 of the apparatus 100 may be moveable in a radial direction with respect to the annular bead core 20 at the second station.
The second nozzle of the apparatus 100 may also be moveable in a radial direction with respect to the annular bead core 20 at the third station.
Overall, the example of
As shown in
If used, the spacers 11 may be fixed to the respective support surface while the support surface rotates and hence rotate together with the respective support surface. In another example, it is also possible to directly rotate the spacers 11 on the respective support surface without rotating the support surface at the same time.
The first station 71 for loading the bead core 20 and the fourth station for unloading the bead core-apex subassembly 5 may be combined into a single station (not shown). Such a design of the apparatus 100 is somewhat simpler but has the disadvantage that its operation is more time-consuming.
The second station 72 for discharging a first rubber compound and the third station 73 for discharging a second or the same rubber compound may be combined into a single station (not shown). In case of such a design of the apparatus 100 there may be even two or more nozzles 51 located about the circumference of the respective station for discharging the same or different rubber compounds.
The first station 71 for loading the bead core 20 and the fourth station for unloading the bead core-apex subassembly 5 may be combined into a single station (not shown). The second station 72 for discharging a first rubber compound and the third station 73 for discharging a second or the same rubber compound may be combined into a single station resulting in an apparatus with only two stations (not shown). Such an apparatus 100 is simpler in its design, requires less space in a plant and may be sufficient for certain applications. Conversely, such an apparatus may be less flexible and may use more time in the manufacture of a bead core-apex subassembly than an apparatus with three stations or an apparatus 100 with four stations, as shown in
Hence, depending on the specific needs and constraints, such as manufacturing time, apex design, available space in a plant, cost and manufacturing complexity, a two-station apparatus, a three-station apparatus, the four-station apparatus of
Numerous examples have been described hereinabove. It will be apparent to those skilled in the art that the above methods and apparatuses may incorporate changes and modifications without departing from the general scope of this invention. It is intended to include all such modifications and alterations insofar as they come within the scope of the appended claims or the equivalents thereof.
