METHOD FOR MANUFACTURING AN AIR TIRE

Description

[0001] The invention relates to a method and a device for manufacturing a pneumatic tire with an inner layer, a carcass layer, a bead core, a tire belt and a tread, wherein during tire construction a particularly uniform distance is created between the inner layer and the carcass layer to the drum shoulder on the circumference of the tire construction drum.

[0002] In the two-stage tire manufacturing process, a shoulder is formed during the construction of a pneumatic tire after the inner liner and a casing ply have been wound on, for example, by expanding the casing drum. A bead core is then formed before the inner liner and casing ply are folded upwards.

[0003] For tire uniformity, it is crucial that the inner liner and the carcass ply exhibit minimal length variations between the bead cores when viewed around the circumference. Uniformity requirements for tires are increasing, and these length variations between the inner liner and the carcass ply between the bead cores are also increasing under standardized processes due to the use of carcass plies with higher stiffness. Therefore, existing methods and equipment, when high uniformity is required, especially when using carcass plies with high stiffness, result in increased reject rates or are particularly complex, thus increasing cycle time and reducing the process's cost-effectiveness.

[0004] Patent EP 2 465 669 A1 discloses a method for manufacturing a pneumatic tire comprising an inner layer, a carcass layer, a bead core, a tire belt and a tread.

[0005] Against this background, the invention is based on the objective of designing a method and a device in such a way that pneumatic tires with an inner layer and a carcass layer can be produced reliably without or with only a slight increase in cycle time, exhibiting particularly small differences in length between the bead cores when viewed around the circumference, in order to reliably meet high uniformity requirements for pneumatic tires.

[0006] This problem is solved by a method according to the features of claim 1 and a device according to the dependent claim. The subclaims relate to particularly advantageous embodiments of the invention.

[0007] According to the invention, a method for manufacturing a pneumatic tire with an inner layer, a carcass layer, a bead core, a tire belt and a tread is provided, comprising the following steps: a) Placing the inner layer and the carcass ply onto a tire building drum and onto a support ring with bellows, b) Forming tire shoulders by expanding the tire building drum, c) Equalizing the distance of the inner layer and the carcass ply to the drum shoulder by smoothing the shoulder area of ​​the carcass ply with finger plates, d) Setting a bead core on the carcass ply at the drum shoulder, e) Fixing the bead core with a radially movable core fixation, f) Folding the carcass ply and the inner layer around the bead core by filling a bellows, g) Completing the tire blank with further steps.

[0008] By coating the inner layer and the carcass ply in the area of ​​the formed tire shoulders with finger plates, whereby this coating is carried out on the circumference of the tire building drum, the inner layer and the carcass ply are homogenized against the tire building drum and the length variation between the bead cores is reduced. This is done before the bead core is attached to the carcass ply, as otherwise reducing the length variation would be more difficult.

[0009] The finger plates can be made of metal or non-metallic materials that have suitable flexibility.

[0010] The term "fixing the bead core with a radially movable core fixation" refers to the method of using a holding element, which is specifically not a bellows.

[0011] A preferred embodiment provides that the equalization of the distance between the inner layer and the carcass ply to the drum shoulder is achieved, at least in partial areas of the inner layer, by reducing the distance between the inner layer and the carcass ply to the drum shoulder. Equalization by reducing the distance, in particular by bringing the inner layer and the carcass ply against the drum shoulder, has proven to be a particularly simple and reliable method of achieving this equalization.

[0012] Another preferred embodiment provides that the finger plates are moved axially to the radially outer shoulder region of the carcass ply and, following this movement, are moved radially in the contact area with the carcass ply to a smaller diameter, with the radial movement preferably being driven by a bead core setter. This embodiment has proven to be effective and reliable, and can be implemented in a particularly simple form, since no additional drive is required when the finger plates are coupled to the bead core setters. The cycle time is also not increased, or at least not significantly.

[0013] Another preferred embodiment provides that the finger plates are moved synchronously. Synchronous movement of the finger plates ensures a particularly reliable and low length variation in the carcass ply.

[0014] Another preferred embodiment provides that the bead core is fixed by a radially movable core fixation device using a plurality of at least four, preferably at least eight, dimensionally stable fixing means distributed around the circumference, wherein the fixing means are preferably moved by an electric, hydraulic, or pneumatic drive, preferably using a mechanical transmission. It has been shown that dimensionally stable fixing means achieve particularly precise positioning of the bead core, resulting in exceptionally high tire uniformity. A higher number of fixing means increases the accuracy with which the bead cores are positioned.

[0015] According to the invention, a device, particularly for carrying out the method according to the invention, is provided, comprising an expandable tire-building drum and a support ring with a bellows arranged axially to the tire-building drum. A core fixation for fixing a bead core to a carcass ply without bellows is arranged on the support ring. For equalizing the distance between the inner layer and the carcass ply to the drum shoulder, the device has finger plates that are movable between a bead core setter and the bellows on the support ring.

[0016] The finger plates allow the inner layer and the carcass ply in the area of ​​the formed tire shoulders to be standardized in terms of length between the bead cores on the circumference of the tire building drum. By fixing the bead core without bellows, length standardization can be achieved before the carcass is formed, thus easily reducing length variation.

[0017] A preferred embodiment provides that the finger plates are mounted to be axially and radially movable, at least in some areas. This axial and radial movableness allows the finger plates to be moved axially to the drum shoulder and then radially across the carcass layer.

[0018] Another preferred embodiment provides that the finger plates are distributed around the entire circumference and preferably overlap each other circumferentially. A distribution around the entire circumference, especially with circumferential overlap, reliably results in particularly low length variations of the carcass ply and the inner layer.

[0019] Another preferred embodiment provides that the finger plates are mechanically coupled to each other and, preferably, mechanically to the bead core setter. Coupling the finger plates results in a uniform movement of the finger plates and thus to low length variation. Coupling the finger plates to the bead core setter has proven to be a particularly simple way to move the finger plates.

[0020] Another preferred embodiment provides that the core fixation is formed from a plurality of at least four, preferably at least eight, dimensionally stable fixing means distributed around the circumference, wherein the fixing means are preferably driven by an electric, hydraulic, or pneumatic drive, preferably using a mechanical transmission. It has been shown that dimensionally stable fixing means achieve particularly precise positioning of the bead core, resulting in exceptionally high tire uniformity. A higher number of fixing means increases the accuracy with which the bead cores are positioned.

[0021] The invention allows for numerous embodiments. To further illustrate its basic principle, one of these is shown in the drawings and described below. These show in Fig. 1a non-expanded tire construction drum with support rings with bellows arranged axially to the tire construction drum; Fig. 2 the expanded tire building drum with a bead core setter and finger plates; Fig. 3 the expanded tire building drum during the setting of a bead core; Fig. 4 the expanded tire construction drum with a folded carcass layer.

[0022] Figure 1 Figure 1 schematically shows an expandable tire drum 1 in an unexpanded state, where the dashed and dotted lines represent axes of symmetry. InIn the axial direction of the tire manufacturing drum 1, a support ring 2 with a bellows 3 is arranged on both sides, the bellows surface 4 being on the same diameter as the tire manufacturing drum surface 5. An inner layer 6 and a carcass layer 7 are placed on the tire manufacturing drum 1 and on the bellows 3. The support ring 2 has a core fixation 8, which consists of eight radially movable metallic elements driven by pneumatic cylinders.

[0023] In Figure 2 is the same expandable tire construction drum as in Figure 1, however, in the expanded state together with a bead core inserter 9 and finger plates 10, is shown. The bead core inserter 9 conveys the bead core 11 axially towards the drum shoulder 12, whereby the movement of the bead core inserter 9 causes the ends of the finger plates 10, which are in contact with the carcass layer 7, to move radially inwards, thereby moving the carcass layer 7 and the inner layer 6 against the drum shoulder 12. The positions of the finger plates 10, the carcass layer 7, and the inner layer 6 at the end of the subprocess are indicated by the dotted and dashed lines.

[0024] In Figure 3 is the same expandable tire construction drum as in Figure 1, however, shown in the expanded state during the setting of the bead core 11. The finger plates 10 have been moved radially inwards by the movement of the bead core setter 9. The carcass ply 7 and the inner layer 6 have been applied to the drum shoulder. Before the bead core setter 9 releases the bead core 11, the core fixation 8 moves radially outwards and fixes the bead core 11.

[0025] After the bead core setter 9 has released the bead core 11, the bellows 3 are filled to form a carcass wrap, so that a carcass wrap is produced as in the Figure 4 is shown. Reference symbol list

[0026] 1 Tire building drum 2 Support ring 3 Bellows 4 Bellows surface 5 Tire building drum surface 6 Inner layer 7 Carcass layer 8 Core fixation 9 Bead core setter 10 Finger plates 11Bead core 12Drum shoulder

Claims

1. Method for producing a pneumatic tyre with an inner layer (6), a carcass ply (7), a bead core (11), a tyre belt and with a tread, comprising the following steps: a) placing the inner layer (6) and the carcass ply (7) onto a tyre-building drum (1) and onto a support ring (2) with a bladder (3), b) forming tyre shoulders by expanding the tyre-building drum (1), c) making the spacing of the inner layer (6) and the carcass ply (7) to the drum shoulder (12) more uniform by passing finger plates (10) over the shoulder region of the carcass ply (7), d) setting a bead core (11) on the carcass ply (7) at the drum shoulder (12), e) fixing the bead core (11) by way of a radially movable core-fixing means (8), f) turning up the carcass ply (7) and the inner layer (6) around the bead core (11) by filling a bladder (3), g) finishing the green tyre by way of further steps.

2. Method according to Claim 1, characterized in that making the spacing of the inner layer (6) and the carcass ply (7) to the drum shoulder (12) more uniform, at least in sub-regions of the inner layer (6), is reducing the spacing of the inner layer (6) and the carcass layer (7) in relation to the drum shoulder (12).

3. Method according to Claim 1 or 2, characterized in that the finger plates (10) are moved axially to the radially outer shoulder region of the carcass ply (7), and the finger plates (10) are subsequently moved, in the region of contact with the carcass layer (7), in a radial direction to a smaller diameter, wherein the radial movement is preferably driven by a bead-core setter (9).

4. Method according to one of the preceding claims, characterized in that the finger plates (10) are moved synchronously.

5. Method according to one of the preceding claims, characterized in that fixing of the bead core (11) by way of a radially movable core-fixing means (8) is realized by moving a multiplicity of at least four, preferably of at least eight, dimensionally stable fixing means distributed over the circumference, wherein the fixing means are preferably moved by way of an electrical or a hydraulic or a pneumatic drive, preferably using a mechanical transmission.

6. Device for producing a pneumatic tyre, in particular for carrying out a method according to one of Claims 1 to 5, having an expandable tyre-building drum (1) and a support ring (2) which is arranged axially in relation to the tyre-building drum (1) and has a bladder (3), wherein a core-fixing means (8) for bladder-free fixing of a bead core (11) to a carcass ply (7) is arranged on the support ring (2), characterized in that that the device has finger plates (10) for making the spacing of the inner layer (6) and the carcass ply (7) to the drum shoulder (12) more uniform, said finger plates being movable between a bead-core setter (9) and the bladder (3) on the support ring (2).

7. Device according to Claim 6, characterized in that the finger plates (10) are mounted so as to be axially and radially movable at least in sub-regions.

8. Device according to either of Claims 6 and 7, characterized in that the finger plates (10) are distributed over the whole circumference and preferably overlap one another in a circumferential direction.

9. Device according to one of Claims 6 to 8, characterized in that the finger plates (10) are coupled mechanically to one another and preferably mechanically to the bead-core setter (9).

10. Device according to one of Claims 6 to 9, characterized in that the core-fixing means (8) is formed from a multiplicity of at least four, preferably of at least eight, dimensionally stable fixing means distributed over the circumference, wherein the fixing means are preferably driveable by way of an electrical or a hydraulic or a pneumatic drive, preferably using a mechanical transmission.