Deposition of a layer of viscous product on the inner surface of a tire

Abstract

The invention relates to a method for depositing a layer of viscous product (2) onto an inner surface (3) of a tread (4) of a tire (1), the method comprising at least the steps of: - rotating the tire (1) about its axis of revolution; - positioning a deposition nozzle (12) at the inner surface (3) of the tread (4), and applying a layer of viscous product (2) onto the inner surface (3), twist by twist. According to the invention, the tire (1) is held in a position such that the axis of revolution of the tire (1) extends at an angle of plus or minus 30° to the horizontal. Figure for the abstract: Fig. 4

Description

Title of the invention: Deposition of a viscous layer on the inner surface of a tire. Technical field

[0001] The present invention relates to the technical sector of tires for vehicles.

[0002] The invention relates more specifically to a method and installation for depositing a layer of viscous product, such as a layer of adhesive material, liquid gum or coating on the inner surface of the tread of a tire.

[0003] The invention also relates to the tire obtained. Previous art

[0004] It is known in the prior art of methods for depositing a layer of viscous product on the inner surface of the tread of a tire.

[0005] For example, it is known to deposit an adhesive layer allowing the attachment of a foam strip for noise-reducing applications.

[0006] It is also known to deposit a layer of viscous product or coating for puncture-proof applications.

[0007] In order to apply this layer of viscous product, the usual method consists of placing the tire to be treated flat on a horizontal support, and rotating the tire around its axis of revolution, which happens to be vertical.

[0008] During the rotation of the tire, a deposition nozzle is positioned directly above the inner surface of the tread to apply concentric "spirals" of product, forming a layer of viscous material over the entire inner surface of the tire tread. The nozzle must deposit the viscous product sufficiently close to the inner surface to "apply" or "smooth" the product so that it adheres properly to the surface.

[0009] This method, although commonly implemented, has several drawbacks.

[0010] Firstly, the internal surface of the tread has an irregular profile, and the application of the product leads to significant and uncontrolled variations in the thickness of the product layer obtained, which: - locally compromises the effectiveness of the puncture-resistant properties; - presents a risk of non-adhesion of the anti-noise strip where applicable, - create an imbalance phenomenon during the rotation of the tire.

[0011] These disadvantages can be exacerbated if, during deposition, the product tends to flow due to gravity. Description of the invention

[0012] One of the aims of the invention is therefore to remedy the problems of the prior art by providing a method and an installation for depositing a layer of viscous product, such as adhesive material, liquid gum or coating on the inner surface of the tread of a tire which are simple, efficient, and which allow to guarantee a uniform deposit on the inner surface of the tread.

[0013] To this end, and according to a first aspect of the invention, a method has been developed for depositing a layer of product onto an internal surface of a tire tread, the method comprising at least steps consisting of: - rotate the tire around its axis of revolution; - Position a deposition nozzle directly over the inner surface of the tread, and apply the layer of product to the inner surface, coil by coil.

[0014] According to the invention, the tire is held in a position such that the axis of revolution of the tire extends at an angle between plus or minus 30° with respect to the horizontal, and is preferably horizontal, or even substantially horizontal.

[0015] In this way, the invention makes it possible to prevent the force of gravity from causing the product to flow, which promotes the deposition of a layer of product of constant thickness on the inner surface of the tread.

[0016] The constant thickness of the applied product layer makes it possible to avoid the phenomenon of imbalance during the rotation of the tire, to have a homogeneous distribution of product so as to have homogeneous anti-puncture effectiveness on the surface of the tread, and also to have homogeneous adhesion of the possible anti-noise strip in order to avoid problems of detachment of said strip.

[0017] Preferably, the method includes steps consisting of measuring a profile of the internal surface upstream of the product layer deposition, and moving the deposition nozzle according to the measurement of the profile, so that the nozzle is always at a constant distance from the internal surface of the tread during the application of the product layer, and therefore that the deposited layer has a constant thickness.

[0018] In order to better control the movements of the nozzle during the deposition of the layer of product, the deposition nozzle is preferably moved by a multi-articulated system.

[0019] The measurement of the internal surface profile can be carried out by laser and / or scanning measurement means, so as to measure precisely and quickly the surface profile of the internal surface of the tread.

[0020] Preferably, the method includes a step of hooking the tire against a rotating support, the tire preferably being clamped by its bead located on the support side, the step of rotating the tire then consists of rotating the support.

[0021] Advantageously, the method includes, prior to the step of applying the layer of product, a step of pulling a sidewall of the tire opposite the support to enlarge access to the tread, and facilitate the deposition of the layer of product.

[0022] According to a second aspect, the invention also relates to an installation for applying a layer of viscous product, such as a layer of adhesive material, liquid gum or coating on the inner surface of a tire for implementing the aforementioned method, said installation comprising a movable deposition nozzle to come to the right of the inner surface of the tread, and along the axis of revolution to apply a layer of product on the inner surface, coil by coil.

[0023] According to the invention, the installation also includes means for rotating the tire so that the axis of revolution of the tire extends at an angle between plus or minus 30° with respect to the horizontal, and preferably horizontally.

[0024] Advantageously, the nozzle is mounted on a head of a multi-articulated system, and the head includes means for measuring the profile of the internal surface of the tread, and the multi-articulated system is configured to move the nozzle radially to the axis of revolution of the tire, the radial movement of the nozzle being controlled by the measuring means so as to allow the application of a layer of product of a constant thickness.

[0025] According to a particular embodiment, the installation also includes a rotating vertical support to hold the tire, and preferably means for attaching the tire to the support configured to clamp the tire by its bead.

[0026] According to a third aspect, the invention relates to a tire comprising a layer of viscous product on the inner surface of its tread, said layer having a constant thickness. Brief description of the drawings

[0027] The [Fig.1] is a side view illustrating a tire on a vertical support, with its horizontal axis of revolution for implementing the method according to the invention.

[0028] [Fig.2] is a side view similar to that of [Fig.1].

[0029] Figure 3 illustrates the sidewall pulling step before the layer application step. of viscous product.

[0030] Fig. 4 illustrates the step of applying the layer of viscous product to the inner surface of the tread.

[0031] Fig. 5 illustrates a cross-sectional view of the tire, where the viscous product layer is deposited on the inner surface of the tread.

[0032] Fig. 6 illustrates the layer of product applied to the inner surface of the tread according to the method according to the invention, with a constant thickness.

[0033] Fig. 7 illustrates the layer of product applied to the inner surface of the tread according to the prior art with a variable thickness. Detailed description of the invention

[0034] With reference to figures 1 to 6, the invention relates to a method of depositing a layer of viscous product (2) on the inner surface (3) of the tread (4) of a tire (1).

[0035] This product can be in various forms, such as a coating, adhesive, resin, liquid gum, silicone, or any material suitable for the desired function, i.e., a puncture-resistant function or a bonding function for another element performing the noise reduction function, such as a foam strip. The thickness of the layer can be adapted according to the material used.

[0036] The tire (1) to be treated comprises a tread (4), sidewalls (5, 6) and beads (7, 8). First, the tire (1) is attached by its bead (7) to a vertical rotating support (9), as illustrated in Figures 1 and 2. Attachment means (10), fixed to the rotating support, press the bead (7) and the sidewall (5) against the surface of the support (9), so that the tire (1) is stationary relative to the reference frame of the rotating support (9).

[0037] Preferably, the support comprises a plurality of attachment means (10) distributed uniformly around a circle to clamp the heel (7) at several points. The attachment means are, for example, hooks that can be moved away from or towards the support.

[0038] The axis of revolution of the tire (1) then extends horizontally, but it is entirely possible that the support is not perfectly vertical so that the axis of revolution of the tire could be inclined by plus or minus 30 degrees per relative to the horizontal, or even plus or minus 10° or plus or minus 5° without going out of the scope of the invention.

[0039] The second free sidewall (6) of the tire (1) is preferably pulled in a direction opposite to the support, for example by means of hooks (11) pulling on the second bead (8), as illustrated in [Fig. 3], so as to open access to the inner surface of the tread and facilitate the passage of the deposition nozzle (12). This operation can be carried out in any suitable manner, for example with a robot. The rotating support is then rotated to also rotate the tire.

[0040] A multi-articulated system, for example an applicator robot (14), comprises a head on which the nozzle (12) is mounted. The multi-articulated system (14) is then maneuvered so as to position the application nozzle (12) in view of and as close as possible to the inner surface (3) of the tread (4) of the tire (1), as shown in [Fig. 4]. The distance between the nozzle and the surface depends on the product to be applied, which a person skilled in the art will be able to apply without difficulty.

[0041] In practice, this multi-articulated system (14) is maneuvered along a trajectory calculated relative to the reference frame of the support (9). The multi-articulated system also allows the nozzle (12) to be moved along the axis of revolution of the tire (1) to deposit a continuous bead of product, coil by coil.

[0042] The multi-articulated system (14) is also configured to move the nozzle (12) radially to the axis of revolution of the tire, i.e., away from or towards the inner surface of the tread. The radial movement of the nozzle (12) is controlled by a measurement of the surface profile of the inner surface (3), which is performed in real time by measuring means (15), for example, a laser, so that the distance between the deposition nozzle (12) and the inner surface (3) of the tread (4) remains constant throughout the deposition process.

[0043] The viscous product is deposited substantially vertically so that gravity does not cause the material to creep. Several beads (16) and / or turns of the product are thus successively deposited on the inner surface (3) of the tire (1) during its rotation. The plurality of beads (16) deposited ultimately forms the final layer of viscous product (2), as illustrated in [Fig. 5].

[0044] In practice, the nozzle (12) slightly smooths the surface of the product during its deposition, so as to ensure greater uniformity of thickness of the beads (16) over the entire circumference of the tread (4). For example, the deposited layer has a constant thickness of between 1 mm and 3 mm.

[0045] It follows from the above that the invention therefore makes it possible to carry out the deposition of a layer of viscous product (2) in a simple and efficient manner, by making it possible to guarantee a uniform deposition on the inner surface of the tread.

Claims

Demands

1. Method of depositing a layer of viscous product (2) on an internal surface (3) of a tread (4) of a tire (1), the method comprising at least steps of: - rotating the tire (1) around its axis of revolution; - positioning a deposition nozzle (12) at the internal surface (3) of the tread (4), and applying a layer of viscous product (2) on the internal surface (3), coil by coil; the method being characterized in that the tire (1) is held in a position such that the axis of revolution of the tire (1) extends at an angle between plus or minus 30° with respect to the horizontal.

2. Method according to claim 1, characterized in that the axis of revolution of the tire is horizontal.

3. A method according to any one of the preceding claims, characterized in that it comprises steps consisting of measuring a profile of the internal surface (3) upstream of the deposition of the viscous product layer (2), and moving the deposition nozzle (12) according to the measurement of the profile so that the nozzle (12) is always at a constant distance from the internal surface (3) of the tread (4) during the application of the viscous product layer (2), and thus the deposited layer has a constant thickness.

4. Method according to any one of the preceding claims, characterized in that the deposition nozzle (12) is moved by a multi-articulated system (14).

5. Method according to claim 3, characterized in that the measurement of the profile of the internal surface (3) is carried out by laser measuring means (15).

6. Method according to any one of the preceding claims, characterized in that cWc comprises a step of hooking the tire (1) against a rotating support (9), the tire preferably being clamped by its bead (7) located on the support side, the step of rotating the tire then consists of rotating the support (9).

7. Method according to claim 6, characterized in that cWc comprises, prior to the step of applying the layer of viscous product (2), a step consisting of pulling a sidewall (6) of the tire (1) opposite the support (9) to enlarge access to the tread (4).

8. Installation for depositing a layer of viscous product (2) onto the inner surface (3) of a tire (1), comprising a movable deposition nozzle positioned to align with the inner surface (3) of the tread (4), and along the axis of revolution to apply a layer of product to the inner surface (3), coil by coil, characterized in that it comprises means for rotating the tire so that the axis of revolution of the tire extends at an angle between plus and minus 30° with respect to the horizontal, and preferably horizontally. - a movable application nozzle (12) movable radially with respect to the axis of revolution of the tire (1).

9. Installation according to claim 8, characterized in that the nozzle (12) is mounted on a head of a multi-articulated system (14), and the head includes means for measuring (15) the profile of the internal surface of the tread, and the multi-articulated system (14) is configured to move the nozzle radially to the axis of revolution of the tire, the radial movement of the nozzle being controlled by the measuring means (15) so as to allow the application of a layer of product of a constant thickness.

10. Installation according to any one of claims 8 to 9, characterized in that it comprises a rotating vertical support (9) for holding the tire, and preferably means for attaching the tire to the support configured to clamp the tire by its bead (7).

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