PROCESS AND PLANT FOR BUILDING TYRES FOR VEHICLE WHEELS

Abstract

There is described a plant for building tyres for vehicle wheels, said tyres being of at least two different models, comprising at least a tyre building line (1) which in turn comprises:—a plurality of work stations (4, 4′, 5, 5′, 6, 12, 14) arranged according to a sequential series, each work station (4, 4′, 5, 5′, 6, 12, 14) being adapted for building at least one structural component of each tyre, assembling at least one elementary component;—at least one handling device (3) for the tyres being processed on the respective forming supports associated to each work station (4, 4′, 5, 5′, 6, 12, 14); and—at least one transfer device (2) adapted for transferring the tyre being processed on its forming support from any first work station (4, 4′, 5, 5′, 6, 12, 14) of said sequential series to any other second work station (4, 4′, 5, 5′, 6, 12, 14) not adjacent thereto of said sequential series, so that the tyre being processed on its forming support only passes in said first and second work station (4, 4′, 5, 5′, 6, 12, 14). There are also described a process for manufacturing tyres for vehicle wheels and a method for selecting work stations (4, 4′, 5, 5′, 6, 12, 14) of a tyre building plant.

Claims

1-51. (canceled)

52. A process for manufacturing tyres for vehicle wheels, the tyres comprising at least two different models, comprising the steps of: b) building at least a first and a second tyre model on respective forming supports, by building each structural component of the first and second tyre models at a plurality of work stations, wherein step b) of building at least the first and second tyre models comprises: a first processing step of transferring and releasing, by a robotized arm of a transfer device, a first forming support holding the first tyre model from a first work station of the plurality of work stations to a second work station of the plurality of work stations, a second processing step of transferring and releasing, by the robotized arm of the transfer device, a second forming support holding the second tyre model from a third work station of the plurality of work stations to a fourth work station of the plurality of work stations, wherein the second processing step occurs at the same time as the first processing step; and wherein during the transfer of the first and second forming supports, the first and second forming supports follow different first and second paths, respectively.

53. The process for manufacturing tyres according to claim 52, wherein the first work station is a first carcass structure building work station and the second work station is a first belt structure building work station.

54. The process for manufacturing tyres according to claim 53, wherein the third work station is a second carcass structure building work station and the fourth work station is a second belt structure building work station.

55. The process for manufacturing tyres according to claim 54, wherein step b) of building at least the first and second tyre models is preceded by a step of: a) arranging a plurality of elementary components of the first and second tyre models at the plurality of work stations.

56. The process for manufacturing tyres according to claim 55, wherein step b) of building at least the first and second tyre models comprises, upstream of the first processing step, a step of: d) selecting the second work station based on tyre model, on a structural component to be built, and on availability of the work stations.

57. The process for manufacturing tyres according to claim 56, wherein step b) of building the at least the first and second tyre models comprises, upstream of the first processing step, a step of: d) selecting the fourth work station based on tyre model, on a structural component to be built, and on availability of the work stations.

58. The process for manufacturing tyres according to claim 57, wherein step b) of building at least the first and second tyre models comprises the steps of: i) building a carcass structure, the carcass structure comprising at least one carcass ply and a pair of annular anchoring structures; ii) building a belt structure, the belt structure comprising at least one belt layer; and iii) building a tread band.

59. The process for manufacturing tyres according to claim 58, wherein, in at least one of the first and second tyre models, a bending ratio between the distance between a radially outer distance of the tread band and a line passing by laterally opposite ends of the tread band, measured on a equatorial plane of the tyre model, and a distance measured along a tyre chord between ends is more than or equal to, about 0.15.

60. The process for manufacturing tyres according to claim 59, wherein the bending ratio is less than or equal to about 0.3.

61. The process for manufacturing tyres according to claim 59, wherein the bending ratio is less than or equal to 0.45.

62. The process for manufacturing tyres according to claim 61, wherein, in step ii), the at least one belt layer comprises a layer of textile or metal cords oriented circumferentially at 0°.

63. The process for manufacturing tyres according to claim 62, wherein step iii) of building the tread band comprises step iii′) of applying a tread band in a position radially external to the belt structure.

64. The process for manufacturing tyres according to claim 63, comprising a step of: iv) applying at least one portion of sidewalls of the tyre model being processed in a position axially external to the tyre model being processed.

65. The process for manufacturing tyres according to claim 64, wherein step iii) of building the tread band comprises, prior to step iii′) of applying the tread band, a step of: iv′) applying at least one tread band underlayer in a position radially external to the belt structure.

66. The process for manufacturing tyres according to claim 65, wherein at least one of steps iii′), iv″) or iv) is carried out by applying at least one continuous elongated element of elastomeric material according to side by side or at least partially overlapped coils.

67. The process for manufacturing tyres according to claim 66, wherein at least one structural component is built by assembling at least one elementary component.

68. The process for manufacturing tyres according to claim 67, further comprising a pre-step of feeding elementary components to at least one work station.

69. The process for manufacturing tyres according to claim 68, wherein the forming support is a toroidal support.

70. The process for manufacturing tyres according to claim 69, wherein the toroidal support has a radially external surface corresponding to a radially internal surface of the tyre being processed.

71. The process for manufacturing tyres according to claim 70, wherein the first and second tyre models differ by size.

72. The process for manufacturing tyres according to claim 71, wherein the first and second tyre models differ by structural components.

73. The process for manufacturing tyres according to claim 72, wherein the first and second tyre models differ by elementary components.

Description

BRIEF DESCRIPTION OF THE DRAWING

[0105] Further features and advantages of invention will appear more clearly from the following description of some preferred examples of methods for selecting work stations, processes for manufacturing tyres and tyre building plants according to the invention, made by way of an indicative non-limiting example with reference to the annexed drawings, wherein:

[0106] FIG. 1 shows a schematic layout of a plant for building tyres for vehicle wheels wherein the method for selecting work stations and the process for manufacturing tyres according to an embodiment of the present invention are carried out.

[0107] With reference to such FIGURE, reference numeral 1 globally indicates a building line of a plant for building tyres for vehicle wheels according to the present invention. The tyres to be built are at least of two different models. Such models may differ in terms of size, structural components and/or elementary components.

[0108] The building line 1 of the plant comprises a plurality of work stations 4, 4′, 5, 5′, 6, 12,

[0109] 14, each of which is adapted for building at least one structural component of each tyre, by assembling at least one elementary component. The work stations 4, 4′, 5, 5′, 6, 12, 14 are arranged according to a sequential series, according to the definition given above.

[0110] The building line 1 of the system further comprises at least one handling device 3 for the tyres being processed on the respective forming supports associated to each work station 4, 4′, 5, 5′, 6, 12, 14. Each handling device 3 is adapted for cooperating with the respective work station 4, 4′, 5, 5′, 6, 12, 14 for assembling said elementary components.

[0111] The building line 1 also comprises at least one transfer device 2, which is adapted for transferring the tyre being processed on its forming support from any first work station of the sequential series to any other second work station even not adjacent to the first one, so that the tyre being processed on its forming support only passes in said first and second work station along a transfer path.

[0112] Said transfer path is the path followed by the forming support 2 and may be of any type (rectilinear, zigzag, etc.). If the transfer takes place from one work station 4, 4′, 5, 5′, 6, 12, 14 to a subsequent one and not adjacent thereto, said transfer path is generally different from the path that would be followed by the transfer support 2 for moving from one work station 4, 4′, 5, 5′, 6, 12, 14 to the work station 4, 4′, 5, 5′, 6, 12, 14 adjacent and subsequent thereto in said sequential series.

[0113] hi particular, the plurality of work stations 4, 4′, 5, 5′, 6, 12, 14 comprises: [0114] at least one carcass structure building work station 4, 4′; [0115] at least one belt structure building work station 5, 5′; and [0116] at least one tread band building work station 6;

[0117] wherein the carcass structure comprises at least one carcass ply and a pair of annular anchoring structures and the belt structure comprises at least one belt layer.

[0118] As shown in the FIGURE, the first carcass structure building work stations 4, 4′ are two, a first carcass structure building work station 4 adapted for building a carcass structure which may be different from the carcass structure built by a second carcass structure building work station 4′. As an alternative, the first carcass structure building work station 4 and the second carcass structure building work station 4′ may carry out the building of the same carcass structure on a respective forming drum, for example in the case of two-ply tyres.

[0119] Each carcass structure building work station 4, 4′ comprises a ply application unit 7 and a bead core application unit 8.

[0120] The bead core application unit 8 is preferably provided with a device exhibiting a dispenser of a continuous elongated element shaped as a rubber metal reinforcing cord, whereas actuators preferably connected to each handling device 3 associated to the carcass structure building work stations 4, 4′, move the forming support so as to wind said continuous elongated element according to preferably radially overlapped coils for manufacturing annular anchoring structures.

[0121] In the embodiment shown in the FIGURE, said belt structure building work stations 5, 5′ are two (whereof only one is detailed in FIG. 1). Each of them comprises an under-belt layer application unit 9 provided with devices for applying an under-belt layer in a position radially external to said carcass structure.

[0122] Each belt structure building work station 5, 5′ further comprises at least one belt layer application unit 10 provided with devices for applying at least a first belt layer in a position radially external to said carcass structure.

[0123] A first belt structure building work station 5 is preferably adapted for applying at least two radially overlapped belt layers, said layers being arranged in such a way that the cords of the first belt layer are oriented sideways relative to the equatorial plane of the tyre being processed, whereas the cords of the second layer also exhibit a slanting orientation but symmetrically crossed relative to the cords of the first layer.

[0124] A second belt structure building work station 5′ of the tyre building plant shown in the FIGURE comprises two belt layer application units 10.

[0125] Preferably, said second belt structure building work station 5′ is adapted for applying at least one belt layer comprising a layer of textile or metal cords, oriented circumferentially at 0°. The tread band building work station 6 of the building line 1 comprises at least one tread band application unit 11.

[0126] In the embodiment shown in the FIGURE, the tread band building work station 6 comprises two tread band application units 11 and one tread band underlayer application unit 13. The latter is provided with devices for applying at least one tread band underlayer.

[0127] However, such tread band underlayer application unit 13 may be arranged outside the tread band building work station 6 in a dedicated building work station.

[0128] The building plant 1 further comprises at least one sidewall building work station 12 provided with a sidewall application unit 17 for building at least a sidewall portion in a position axially external to the tyre being processed.

[0129] The building plant 1 shown in FIG. 1 further comprises work station for applying a liner 14 provided with a liner application unit 18.

[0130] The building line 1 is provided with a strip-like element feeding unit 16 for each carcass structure building work station 4, 4′. Similar strip-like element feeding units may be provided for each belt structure building work station 5, 5′.

[0131] Preferably, at least one of the above work stations 4, 4′, 5, 5′, 6, 12, 14 in sequential series comprises a device that exhibits a dispenser of a continuous elongated element of elastomeric material. In this case, each work station provided with such device also comprises one or more actuators for moving the forming support so as to wind the continuous elongated element according to side by side and/or at least partially overlapped coils. Even more preferably, at least the under-belt layer application unit 9, the tread band underlayer application unit 13, the tread band application units 11, the sidewall application unit 17, the liner application unit 18, comprise each the above device.

[0132] The tyre building plant according to an embodiment of the invention may comprise a preparation line for some elementary components (generally strip-like elements and/or rubber cords) adapted for being fed to the work stations 4, 4′, 5, 5′. Such line is not shown in the FIGURE.

[0133] The transfer device 2 adapted for transferring the tyre being processed on its forming support from a work station to another work station of the sequential series comprises a robotized arm. Preferably, the transfer device 2 is associated to a guiding track 15 whereon such robotized arm moves. Preferably, each handling device 3 for the tyres being processed on the respective forming supports comprises at least one robotized arm.

[0134] According to preferred embodiments of the present invention, at least one model of tyre to be built is for two-wheel vehicles, wherein the bending ratio R between the distance between the radially outer distance of the tread band and the line passing by the laterally opposite ends of the tread band itself, measured on the equatorial plane of the tyre, and the distance measured along the tyre chord between said ends is more than or equal to, about 0.15.

[0135] hi particular, said bending ratio R is less than or equal to, about 0.3 or less than or equal to, about 0.45, based on the fact that the tyre to be built is of the rear or front type.

[0136] Preferably, the forming support is a toroidal support. Even more preferably, the toroidal support has a radially external surface corresponding to a radially internal surface of the tyre being processed (and built).

[0137] The method for selecting work stations 4, 4′, 5, 5′, 6, 12, 14 in a building line 1 of tyres in at least two different models, wherein said building line 1 comprises a plurality of work stations 4, 4′, 5, 5′, 6, 12, 14 arranged according to a sequential series, wherein each work station 4, 4′, 5, 5′, 6, 12, 14 is adapted for building at least one structural component of each tyre, preferably by assembling at least one elementary component, according to the present invention, comprises the step of: [0138] selecting at least two work stations 4, 4′, 5, 5′, 6, 12, 14 not adjacent to each other whereto a tyre being processed is transferred based on the tyre model, on the structural component to be built and on the availability of the work stations themselves.

[0139] The transfer is carried out so that the tyre being processed only passes in said at least two work stations 4, 4′, 5, 5′, 6, 12, 14 along a transfer path.

[0140] The method for selecting work stations 4, 4′, 5, 5′, 6, 12, 14 comprises, prior to the selection step, the step of receiving information on the model of tyre to be built and on the availability of the work stations 4, 4′, 5, 5′, 6, 12, 14.

[0141] In other words, the selection method according to the invention provides for the reception of the above information and the processing thereof so as to select the most suitable work stations 4, 4′, 5, 5′, 6, 12, 14 to transfer the tyres being processed.

[0142] Preferably, according to a step a), the tyre building process provides for arranging a plurality of elementary components of the tyres to be built at a plurality of work stations 4, 4′, 5, 5′, 6, 12, 14.

[0143] Afterwards, the process provides for a step b) of building at least a first and a second model of tyre on respective forming supports, building each structural component, preferably by assembling at least one of said elementary components, at the work stations 4, 4′, 5, 5′, 6, 12, 14. The latter are arranged according to a sequential series in a tyre building line 1, wherein the tyres being processed on the respective forming supports are transferred from one work station 4, 4′, 5, 5′, 6, 12, 14 to the other by a transfer device 2.

[0144] According to the invention, the step b) of building at least a first and a second tyre model comprises at least one step c) of transferring a tyre being processed on its own forming support from a first work station 4, 4′, 5, 5′, 6, 12, 14 of the building line 1 to a second work station 4, 4′, 5, 5′, 6, 12, 14 not adjacent thereto in said sequential series.

[0145] Moreover, according to the process of the invention, each transfer step c) is carried out so that the tyre being processed on its forming support only passes in said first and second work station 4, 4′, 5, 5′, 6, 12, 14 along a transfer path.

[0146] According to a preferred embodiment, the building step b) comprises, upstream of the transfer step c), a step of:

[0147] d) selecting the work station 4, 4′, 5, 5′, 6, 12, 14 whereto a tyre being processed is transferred based on the tyre model, on the structural component to be built and on the availability of the work stations 4, 4′, 5, 5′, 6, 12, 14 themselves.

[0148] The building step b) is preferably carried out by transferring the tyre being processed from a work station 4, 4′, 5, 5′, 6, 12, 14 to a subsequent work station 4, 4′, 5, 5′, 6, 12, 14 of said sequential series. That is, the transfer takes place according to a travelling direction of the building line 1.

[0149] In particular, the building step c) comprises the steps of:

[0150] i) building a carcass structure, which comprises at least one carcass ply and a pair of annular anchoring structures;

[0151] ii) building a belt structure, which comprises at least one belt layer; and

[0152] iii) building a tread band.

[0153] According to a preferred embodiment, the above step ii) comprises building a belt structure provided with a layer of textile or metal cords, oriented circumferentially at 0°. The process for manufacturing tyres further comprises a pre-step of feeding elementary components into the corresponding work station.

[0154] With reference to the tyre building line 1, an operating example of the plant illustrated in FIG. 1 shall now be described, for example in the case of two models of tyres A and B, where A is a one-ply tyre and B is a two-ply tyre, A and B having both a layer of metal cords at 0° as belt structure.

[0155] A forming support for tyre A being processed is transferred to the liner application work station 14 wherein the liner application unit 18 applies a liner layer thereon, preferably by the application of at least one continuous elongated element of elastomeric material according to side by side and/or overlapped coils. Such liner application step may be preceded by an application step of at least one bead reinforcing fabric and/or by an application step of an abrasion-proof element on the forming support of tyre A.

[0156] Afterwards it is also possible to apply a under-liner layer in a position radially external to the liner layer.

[0157] Tyre A being processed is transferred to a carcass structure building work station 4 or 4′—according to the type of ply required by tyre A or to the availability of said work stations 4, 4′—where, according to step i), the building of the carcass structure is carried out. hi this example, the one-ply tyre A is carried by the transfer device 2 from the liner application work station 14 directly to the second carcass structure building work station 4′ as the latter is free, without passing by the first carcass structure building work station 4, according to what provided in the selection step of said method and with step c) of the process according to the invention.

[0158] hi said second carcass structure building work station 4′, a carcass ply is applied in a position radially external to the liner layer or to the under-liner layer (if provided), by the ply application unit 7, preferably by laying a plurality of strip-like elements side by side to each other. According to different project specifications, further elementary components may be applied to manufacture further structural components of the carcass structure.

[0159] Afterwards, step i) provides for applying at least a pair of annular anchoring structures at the axially opposite ends of the carcass ply. Such step is carried out by the bead core application unit 8, the operation whereof has been illustrated hereinbefore.

[0160] Afterwards it is possible to apply, at the carcass ply of tyre A being processed, a plurality of inside and/or outside reinforcing elements and/or an abrasion-proof element. At the same time as the building of tyre A, also tyre B is built according to step b) of the process illustrated above.

[0161] More precisely, the forming support of tyre B being processed is transferred to the liner application work station 14 as soon as this is left free by tyre A being processed. The same process described above for tyre A is carried out in the above liner application work station 14.

[0162] According to step i) of the present invention, the carcass structure building is then carried out: Tyre B being processed is transferred by the transfer device 2 into the first carcass structure building work station 4 for applying the first carcass ply, such work station is free since tyre A has been transferred to the second carcass structure building station 4′. After that, the transfer device 2 transfers tyre B into the second carcass structure building work station 4′ for applying the second carcass ply once that tyre A, completed its carcass structure building step, has been transferred from the above work station.

[0163] In particular, in the second carcass structure building work station 4′ a second carcass ply is applied in a position radially external to the first carcass ply of tyre B with methods similar to those of application of the first carcass ply. Such step is followed by the application of at least a further pair of annular anchoring structures at the axially opposite ends of the second carcass ply.

[0164] According to step c), tyre A being processed is then transferred by the transfer device 2 into the second belt structure building work station 5′.

[0165] In other words, in the example illustrated herein, tyre A being processed is transferred from the second carcass structure building work station 4′ to the second belt structure building work station 5′ without passing through the first belt structure building work station 5.

[0166] In such second belt structure building work station 5′ there is carried out the step ii) of building the belt structure which, in this specific example, provides first for the application of an under-belt layer in a position radially external to tyre A being processed by the under-belt layer application unit 9, preferably by the application of at least one continuous elongated element of elastomeric material according to side by side and/or partially overlapped coils, then the application of a belt layer obtained by the application of a rubber metal cord layer oriented circumferentially at 0°, in a special belt layer application unit 10. According to the above step c), tyre B being processed is transferred by the transfer device 2 into the second belt structure building work station 5′.

[0167] In other words, tyre B being processed is transferred from the first carcass structure building work station 4 to the second belt structure building work station 5′ without passing through the work station 5.

[0168] Moreover, it should be noted that thanks to the preferred configuration of the second belt structure building work station 5′ (two belt layer application units 10), the transfer of tyre B in the above work station can advantageously take place even if in said work station there is still tyre A.

[0169] The step ii) of building the belt structure of tyre B is carried out in such work station 5′ similarly to what described above for building tyre A.

[0170] Tyre A being processed is then transferred by the transfer device 2 into the tread band building work station 6 wherein the tread band building step iii) is carried out. Such step iii) may comprise the sub-step iii″) of applying at least one tread band underlayer in a position radially external to the belt structure, in the tread band underlayer application unit 13. The step iii) finally comprises the sub-step iii″) of applying at least one tread band layer in a position radially external to said tread band underlayer, if provided, or to said belt structure, in a tread band application unit 11. If the tread band layers are two, these are preferably applied in a sequence in the two respective tread band application units 11. Preferably, at least one between the above steps iii′) and iii″) are carried out by applying at least one continuous elongated element of elastomeric material according to side by side and/or at least partially overlapped coils.

[0171] At the end of the building of the belt structure, also tyre B being processed is transferred by the transfer device 2 into the tread band building work station 6 wherein the tread band building step iii) is carried out with methods similar to those described for building the tread band of tyre A.

[0172] Also in this case, thanks to the preferred configuration of the tread band building work station 6 (two tread band application units 11), tyre B can be transferred to the above tread band building work station 6 while tyre A is still present, further improving productivity.

[0173] Afterwards, tyre A being processed is transferred by the transfer device 2 into the sidewall building work station 12. In such work station 12 the sidewall application unit 17 provides to applying at least one portion of sidewalls of tyre A in a position axially external to said tread band, carrying out step iv), by the application of at least one continuous elongated element of elastomeric material according to side by side and/or partially overlapped coils.

[0174] After that, also tyre B being processed is transferred by the transfer device 2 into the sidewall building work station 12 wherein the sidewall application unit 17 provides to applying at least one portion of sidewalls of tyre B with methods similar to those described for tyre A.

[0175] Tyres A and B thus built are transferred to optional further work stations for the application of optional elements such as barcodes, labels, etc. or in output from the building line 1 to proceed towards a moulding and vulcanisation unit, not shown herein.

[0176] Within the scope of the above present description and in the following claims, all numerical values indicating amounts, parameters, percentages and so on are always to be deemed as preceded by the term “about”, if not otherwise stated. Moreover, all numerical value ranges include all possible combinations of the maximum and minimum numerical values and all possible intermediate ranges, besides those specifically indicated in the text.