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) on 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) in line with the inner surface (3) of the tread (4), and applying a layer of viscous product (2) to the inner surface (3), turn by turn. 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 between plus or minus 30° relative to the horizontal.

Description

Description Title of the invention: Deposition of a layer of viscous product on the inner surface of a tire technical field

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

[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 resulting tire. Previous art

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

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

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

[0007] 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 tire rotation, a deposition nozzle is positioned directly against the inner surface of the tread to apply concentric "spirals" of product, forming a layer of viscous material across the entire inner surface of the tire tread. The nozzle must deposit the viscous product close enough to the inner surface to "apply" or "smooth" it so that it adheres properly.

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

[0010] Firstly, the inner 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 resulting product layer, which: - locally compromises the effectiveness of the puncture-resistant properties; - presents a risk of the noise-reducing strip failing to adhere properly, if 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.

[0012] Also known are documents CN111511536 and CN111465488 which describe solutions known from the prior art. Description of the invention

[0013] One of the aims of the invention is therefore to remedy the problems of the prior art by providing a method and 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 guarantee a uniform deposit on the inner surface of the tread.

[0014] 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.

[0015] 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.

[0016] In this way, the invention prevents 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.

[0017] The constant thickness of the applied product layer helps to avoid the phenomenon of imbalance during tire rotation, to have a homogeneous distribution of product so as to have homogeneous anti-puncture efficiency 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.

[0018] Preferably, the method includes steps of measuring a profile of the inner surface upstream of the product layer deposition, and moving the deposition nozzle according to the profile measurement, so that the nozzle is always at a constant distance from the inner surface of the tread when applying the product layer, and therefore the deposited layer has a constant thickness.

[0019] In order to better control the movements of the nozzle during the deposition of the product layer, the deposition nozzle is preferably moved by a multi-articulated system.

[0020] The measurement of the internal surface profile can be carried out by laser and / or scanning means, so as to accurately and quickly measure the surface profile of the internal surface of the tread.

[0021] 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.

[0022] Advantageously, the method includes, prior to the step of applying the layer of product, a step of pulling one sidewall of the tire opposite the support to enlarge access to the tread, and facilitate the deposition of the layer of product.

[0023] 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, to the inner surface of a tire. for the implementation of 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.

[0024] 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.

[0025] Advantageously, the nozzle is mounted on a head of a poly-articulated system, and the head includes means for measuring the profile of the internal surface of the tread, and the poly-articulated system is configured to move the nozzle radially to the axis of revolution of the tire, the radial movement of the nozzle being servo-controlled to the measuring means so as to allow the application of a layer of product of a constant thickness.

[0026] 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.

[0027] 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

[0028] 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.

[0029] [Fig.2] is a side view similar to that of figure 1.

[0030] Figure 3 illustrates the flank drawing step before the viscous product layer application step.

[0031] Figure 4 illustrates the step of applying the layer of viscous product to the inner surface of the tread.

[0032] Figure 5 illustrates a cross-sectional view of the tire, where the viscous product layer is deposited on the inner surface of the tread.

[0033] Figure 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.

[0034] Figure 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

[0035] 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).

[0036] This product can take many forms, such as a coating, adhesive, resin, liquid gum, silicone, or any material suitable for the desired function, i.e., puncture protection or bonding to another element that provides noise reduction, such as a foam strip. The layer thickness can be adjusted depending on the material used.

[0037] 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).

[0038] Preferably, the support includes a plurality of attachment means (10) evenly distributed 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.

[0039] The axis of revolution of the tire (1) then extends horizontally, but it can quite be envisaged that the support is not quite vertical so that the axis of revolution of the tire could be inclined by more or less 30 degrees with respect to the horizontal, or even more or less 10° or more or less 5° without going out of the scope of the invention.

[0040] The second free sidewall (6) of the tire (1) is preferably pulled in the opposite direction to the support, for example by means of hooks (11) pulling on the second bead (8), as illustrated in Figure 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.

[0041] 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 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 Figure 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.

[0042] 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.

[0043] 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.

[0044] The viscous product is deposited almost vertically so that gravity does not cause the material to creep. Several beads (16) and / or coils of 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 Figure 5.

[0045] In practice, the nozzle (12) slightly smooths the surface of the product during its deposition, in order to ensure a more uniform thickness of cords (16) around the entire circumference of the tread (4). As an example, the deposited layer has a constant thickness between 1 mm and 3 mm.

[0046] 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 for depositing a layer of viscous product (2) onto an internal surface (3) of a tread (4) of a tire (1), the method comprising at least steps consisting of: - rotate the tire (1) around its axis of revolution; - position a deposition nozzle (12) at the right of the inner surface (3) of the tread (4), and to apply a layer of viscous product (2) on the inner surface (3), strand by strand; 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. 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 therefore 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 it includes a step of hooking the tire (1) against a rotating support (9), the tire being preferably 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 it comprises, prior to the step of applying the layer of viscous product (2), a step 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) on the inner surface (3) of a tire (1), comprising a movable deposition nozzle to come to the right of the inner surface (3) of the tread (4), and along the axis of revolution to apply a layer of product on 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 or minus 30° with respect to the horizontal, and preferably horizontally. - a mobile application nozzle (12) that can be moved 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. An 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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