Method for installing vent valves in a tire mold lining

Abstract

The present invention relates to a method for installing vent valves (24) in a lining sector (9) of a tire mold, the method comprising the following steps: - fixing the sector (9) to a support (10), - acquiring images of the sector (9) from different viewing angles, the acquisition being carried out in an acquisition station (3), - generating a three-dimensional map of the sector (9) from the images, - identifying vent valve (24) openings in the sector (9) using the map, the identification of the openings including referencing the position of the openings relative to the support (10), - moving the support (10) to an installation station (16) different from the acquisition station (3), and - installing a vent valve (24) in each opening, the installation being carried out in the installation station (16). Figure for the abstract: Figure 1

Description

Title of the invention: Method for installing vent valves in a tire mold lining FIELD OF INVENTION

[0001] The invention relates to a method for installing vent valves in a tire mold lining, and in particular an automated installation method. PRIOR TECHNOLOGY

[0002] Before molding a tire, it is necessary to install vent valves in the mold linings. These vent valves allow air to escape from the mold when the tire material is inserted. When vent valves are installed manually, the operator must perform meticulous, time-consuming, and ergonomically undesirable work, particularly due to the required posture and the repetitive nature of the task.

[0003] There is a need to develop a method for installing a vent valve that reduces the arduousness of manual tasks. Description of the invention

[0004] One aim of the present exposition is to propose a method for installing a vent valve which reduces the arduousness of manual tasks compared to the prior art.

[0005] The objective is achieved by means of a method for installing vent valves in a lining sector of a tire mold, the method comprising the following steps:

[0006] - fixing the sector to a fixing support,

[0007] - acquisition of images of the sector from different viewpoints of the sector, the acquisition being carried out in an acquisition station,

[0008] - generation of a three-dimensional map of the sector from the images,

[0009] - identification in the vent valve orifice area using the Mapping, identification of openings including referencing the position of the openings relative to the support,

[0010] - moving the support to a placement station different from the acquisition station, and

[0011] - installation in each orifice of a vent valve, the installation being carried out in the installation station.

[0012] Such a method is advantageously and optionally complemented by the following various features taken alone or in combination: - a step of determining the orientation of the orifice for each orifice, the installation of the vent valve taking into account the orientation of the orifice; - the identification of orifices includes a step of detecting a cylindrical shape in the mapping; - determining the diameter of each orifice includes a step of adjusting the cylindrical shape so that the cylindrical shape passes through a maximum number of points in the mapping; - the identification step in the vent valve orifice sector includes the determination for each orifice of an orifice diameter, the process including a step of determining for each orifice a vent valve size suitable for the orifice, the valve size being part of a set of valve sizes, the installation step being configured to install in each orifice a vent valve having the size suitable for the orifice; - a data transmission step from the acquisition station to the installation station; - a step to verify the valve installation; and - the image acquisition stage includes several rotations of the sector relative to a camera, with the number of rotations being greater than or equal to four.

[0013] The presentation also relates to a device for installing vent valves in a lining sector of a tire mold, the device comprising:

[0014] - a fixing support for the trim sector,

[0015] - an acquisition station comprising a photographic device,

[0016] - a conveyor configured to set the sector in motion relative to the camera,

[0017] - a processor configured to generate a three-dimensional map of the sector Using images of the area, identify vent valve openings within the area using mapping.

[0018] - a laying station comprising a controlled device for laying in each an opening, a vent valve, and

[0019] - a carrier configured to move the media from the acquisition station to the installation station. DESCRIPTION OF THE FIGURES

[0020] Other features and advantages will become apparent from the following description, which is purely illustrative and not limiting, and should be read in conjunction with the accompanying drawings on which:

[0021] [Fig. 1] [Fig. 1] is a schematic representation of an example of a vent valve installation device; and

[0022] [Fig.2] [Fig.2] is a schematic representation of an example of a method of Installation of vent valves. DETAILED DESCRIPTION OF THE INVENTION

[0023] A tire mold has a central axis that corresponds to the axis of the tire to be produced. The mold comprises mold sectors arranged angularly around the axis. Each sector corresponds to an angular sector of the mold, typically with a 25-degree angle. The mold sectors correspond to the outer parts of the mold. During the molding process, the mold sectors are assembled and mechanically mounted against each other to form the mold.

[0024] Within each sector, the mold includes a lining sector. It is the lining sector that is in contact with the tire material, for example, the rubber, during the molding process. It is the lining sector that creates the tread pattern of the tire. A lining sector comprises a rear face intended to be in contact with the mold sector and a front face intended to be in contact with the tire material during the molding process.

[0025] The various lining sectors, like the various mold sectors, are distributed angularly around the axis. Each lining sector typically extends over an angle of 25 degrees, and the assembly of the various lining sectors constitutes the mold lining. There are different types of linings, including winter tire linings and summer tire linings.

[0026] Each tread sector is perforated with holes. Each hole has a cylindrical shape with a circular cross-section. Each hole passes completely through the sector in a radial or nearly radial direction. Advantageously, the direction of the hole's extension is orthogonal to a local curvature of the inner tread relief. The inner tread relief of the tread is the part of the tread that provides the tread pattern of the tire.

[0027] Each orifice is characterized by a diameter, a position in the packing sector and an orientation relative to the packing sector.

[0028] The orifice is intended to accommodate a vent valve.

[0029] In a packing sector, the orifices do not necessarily all have the same size, because the sector may be designed to receive valves of different sizes. There is then a set of valve sizes that differ from one another. For example, the packing sector may receive a first type of vent valve with a diameter of 2.5 mm and a second type of vent valve with a diameter of 3 mm. Alternatively, the set of valve sizes includes a first length of a first type of valve and A second valve type has a length of 10 mm. Both valve types have the same diameter. The valve diameter is measured in a transverse plane. A vent valve typically has a length or height of 10 mm. The length or height of the valve is measured longitudinally. The longitudinal direction is perpendicular to the transverse plane.

[0030] When the vent valve is inserted into the orifice, the longitudinal direction of the valve corresponds to the extension direction of the orifice.

[0031] In relation to [Fig.1], a device 1 for installing vent valves includes an acquisition station 3. The acquisition station 3 includes a photographic camera 5. The photographic camera may in particular be a three-dimensional camera called a 3D camera.

[0032] The camera 5 is connected to a processor 14. The processor 14 is configured to control the camera's shooting parameters and trigger image capture. The processor 14 is configured to process the images produced by the camera 5. In particular, the processor 14 is configured to generate a three-dimensional map of the object from a plurality of images. A three-dimensional map is a model of the object's surface topography. For a mesh of the object's surface, that is, for a plurality of points regularly distributed on the object's surface, the positions of these different points in space are measured in a reference frame defined by an origin point and three axes forming an orthonormal basis. The set of coordinates of the points measured with respect to the reference frame gives the three-dimensional map.This generation of mapping can be based, in particular, on a photogrammetry technique.

[0033] The processor 14 is also configured to identify and characterize specific shapes in a three-dimensional map. Among these specific shapes, the processor 14 is configured to identify and characterize cylindrical shapes with a circular cross-section. In other words, the processor can use: - a method of traversing or scanning the map to detect an area of ​​the map which has a cylindrical shape with a circular cross-section, and - a fitting method applied to the area to determine the cylindrical shape parameters of the area, typically a diameter and a length; this fitting may in particular correspond to searching for a virtual cylinder which passes through as many points as possible in the area of ​​the map, so that the cylindrical shape passes through a maximum number of points in the map.

[0034] The camera 5 is mounted on a mechanical actuator 7 or automatic arm 7. The mechanical actuator 7 allows the camera to be moved and oriented. tographic 5.

[0035] The acquisition station 3 includes a base 12 configured to receive a trimming sector 9. The trimming sector 9 can be positioned so that the rear face of the sector is located between the base 12 and the front face of the sector. The front face of the sector faces outwards; it does not face the base 12.

[0036] The base 12 may have degrees of freedom, in particular in rotation, to move and orient the trim sector 9 relative to the camera 5. The base 12 includes a conveyor configured to move the trim sector 9 relative to the camera, in particular to move it in rotation.

[0037] In particular, the base 12 can be controlled in rotation around a vertical axis Z. The base 12 is for example connected to the processor 14 so that the position of the base 12 can be controlled in rotation from the processor 14.

[0038] Advantageously, the trim sector 9 is fixed to the base 12 via a support 10. The support 10, which is a fixing support for the trim sector 9, can then serve as a spatial reference for the trim sector. The fixing of the trim sector 9 to the support 10 can be precise to the micron. The support 10 may have one or more markings that allow the support 10 to be spatially referenced in the frame of reference of the acquisition station or subsequently in another station.

[0039] Also in relation to [Fig. 1], the vent valve setting device 1 comprises a setting station 16. The setting station 16 is different from the acquisition station 3. The device 1 includes a conveyor configured to move the packing sector 9 from the acquisition station to the setting station. Advantageously, the conveyor is configured to move the packing sector 9, fixed to its support, from the acquisition station to the setting station. The setting station 16 includes a valve setting head 18. The setting head 18 is configured to place a valve 24 inside an orifice of the packing sector 9. The setting head 18 is connected to a valve reservoir 20 by a conduit 22. The setting head has a setting axis, which is the axis along which the head moves the vent valve. During this movement, the setting axis corresponds to the longitudinal direction of the valve.

[0040] The laying head 18 is fixed to a mechanical actuator or articulated arm 26 which is configured to move and orient the laying head 18.

[0041] The installation station 16 includes a base 28 configured to fix the packing sector 9 during valve installation. The base 28 includes one or more degrees of freedom to move and orient the packing sector 9.

[0042] When the placement station 16 and the acquisition station 3 merge into a single station, the base 28 corresponds to the base 12.

[0043] The installation station 16 includes a control unit 30 which is configured for order the position and orientation of the mounting head 18 and the base 28.

[0044] The processor 14 is connected to the installation station 16 and in particular to the control unit 30 to transmit data and in particular a three-dimensional map.

[0045] A vent valve installation device as just presented allows implementation of a vent valve installation method P which is now described and which is schematically illustrated in [Fig.2].

[0046] In a first step SI, the trimming sector 9 is fixed to the reference support 10. This first step SI is optional. In particular, when the acquisition station 3 and the placement station 16 form a single station, it is not essential to carry out this step SI.

[0047] During a second step S2, the camera 5 takes a plurality of images of the trim sector 9. In particular, these images are images of the front face of the trim sector 9. The second step S2 is carried out in the acquisition station.

[0048] Advantageously, the camera is positioned at a distance of approximately 400 mm from the center of the front face of the trim sector 9. This distance may be greater than or equal to 300 mm and less than or equal to 500 mm. The camera has an optical axis. The camera is oriented so that its optical axis passes through the trim sector 9 and ideally the center of the front face of the trim sector 9. The camera is oriented so that its optical axis forms a non-zero angle with a horizontal plane. The angle is greater than or equal to 25° and less than or equal to 75°. For example, the angle is 45° or 50°.

[0049] The images are acquired during step S2 from different viewing angles. In particular, it is possible to rotate the trim sector 9 around a vertical axis passing through the trim sector 9 between two image acquisitions. Equivalently, the camera can be rotated around this axis between two image acquisitions.

[0050] For example, four photographs can be acquired, and between two acquisitions, the trim sector 9 can be rotated by 90° around the vertical axis. Alternatively, five photographs can be acquired, and between two acquisitions, the trim sector 9 can be rotated by 72° around the vertical axis. More generally, n photographs can be acquired, and between two acquisitions, the trim sector 9 can be rotated by (360 / n)° around the vertical axis.

[0051] During a third step S3, the processor 14 generates a three-dimensional map of the trim sector 9 from the images acquired during the second step S2.

[0052] During a fourth step S4, the processor 14 identifies one or more vent valve ports in the packing sector 9 using the mapping. The processor may, in particular, implement: - the mapping traversal or scanning process mentioned above to identify cylindrical shapes in the trim sector, and - the adjustment process mentioned above to determine a measurement of the diameter of the identified cylindrical shape(s).

[0053] During step S4, the processor 14 identifies one or more orifices in the packing sector and determines the position of each orifice. When the packing sector 9 is fixed to the reference support 10, the identification of the orifices can advantageously include referencing the position of the orifices relative to the support 10. The support 10 then serves as a spatial reference for the packing sector 9, and it is possible to use in the setting station 16 the entire geometric characterization of the packing sector 9 carried out during steps S4, S5, and S6 in the acquisition station 3. The information concerning the position, orientation, diameter, and valve type associated with each orifice is transmitted to the setting station 16, and in particular to the control unit 30.

[0054] Optionally, the processor 14 determines a diameter of the orifice for each hole.

[0055] During a fifth step S5, the processor 14 can determine an orientation of the orifice which is given by the orientation of the axis of the cylinder with respect to the base of the three-dimensional mapper.

[0056] During a sixth step S6, the processor 14 associates each identified orifice with a type of valve to be installed in the orifice. When all the valves to be installed have the same dimensions, and in particular the same diameter, the processor 14 always associates the same type of valve. However, if the orifices to be installed do not all have the same size, and if there is a set of valve sizes different from one another, then the association made by the processor 14 is based in particular on the diameter of the orifice determined during the fourth step S4. For an identified orifice, the determined diameter is compared to the different valve sizes intended to be installed in the packing area, i.e., to candidate diameters, for example, 2.5 mm and 3 mm, as mentioned above.When the difference between the determined diameter and one of the candidate diameters is less than or equal to a threshold, then the orifice is associated with the corresponding valve type. When, for each of the candidate diameters, the difference between the determined diameter and the candidate diameter is greater than the threshold, then the orifice is not taken into account for subsequent steps of the process.

[0057] During an optional seventh step S7, the trim sector 9 is moved from acquisition station 3 to installation station 16. This step is not necessary when these two stations form a single station. When this seventh step S7 is implemented, it is advantageous for the packing sector 9 to be fixed to a reference support 10. The support 10 can then serve as a spatial reference for the packing sector 9, and it is possible to use in installation station 16 the entire geometric characterization of the packing sector 9 carried out during steps S4, S5, and S6 in acquisition station 3. The information concerning the position, orientation, diameter, and valve type associated with each orifice is transmitted to installation station 16, and in particular to the control unit 30.

[0058] During an eighth step S8, vent valves are installed in the orifices. Step S8 is carried out in the installation station.

[0059] As previously determined for each orifice a diameter and a suitable size of vent valves, it is possible in step S8 to fill the orifices with several types of valves, and in particular valves of different diameters.

[0060] For each identified orifice associated with a valve type, the position and type of valve to be installed are known. This simplifies the installation process. This is particularly true when an operator performs the installation. Manual labor time is reduced, since there is no uncertainty about which type of valve to choose based on the orifice.

[0061] Alternatively, the installation can be carried out using the installation head 18. In this case, an automated module installs a vent valve in each orifice. The use of this automated module, namely the installation head 18, eliminates the need for manual installation of the vent valves. The associated manual tasks and their associated physical strain are thus eliminated.

[0062] The method can be implemented for any type of tire lining, including winter and summer tire linings. In particular, the method can be applied to certain lining sectors that comprise lining sub-sectors. These sub-sectors can be handled in batches and laid flat against each other to perform valve seat installation. The shape of the lining sector during this installation is not the same as the shape of the lining sector during molding. A subsequent step involves adjusting the shape of the lining sector during mold mounting.

[0063] Moreover, thanks to this process, it is not necessary to have a 3D CAD (three-dimensional computer-aided design) model of the packing sector to place valves in all the orifices of the sector.

[0064] For each orifice to be filled, the control unit 30 controls, on the one hand, the mechanical actuator or articulated arm 26 which moves and orients the placement head 18 and, on the other hand, the A base 28 moves and orients the packing section 9 so that the insertion head 18 is positioned opposite the orifice to be filled. The insertion head 18 is equipped with a vent valve 24 from the reservoir 20. The insertion head 18 inserts the vent valve 24 into the orifice to be filled over a controlled length.

[0065] For each identified orifice associated with a valve type, the position and type of valve to be installed are known. For each orifice to be filled, the control unit 30 controls, on the one hand, the mechanical actuator or articulated arm 26, which moves and orients the insertion head 18, and on the other hand, the base 28, which moves and orients the packing sector 9 so that the insertion head 18 is positioned opposite the orifice to be filled. The insertion head 18 is fitted with a vent valve 24 from the reservoir 20. The insertion head 18 inserts the vent valve 24 into the orifice to be filled over a controlled length.

[0066] When the processor 14 has determined the orientation of the orifice during step S5, this orientation is taken into account during the eighth step S8. For each orifice to be filled, the control unit 30 controls, on the one hand, the mechanical actuator or articulated arm 26, which moves and orients the setting head 18, and on the other hand, the base 28, which moves and orients the packing sector 9 so that the axis of the setting head 18 is aligned with the extension direction of the axis of the orifice to be filled. Determining the orientation of the orifice relative to the sector then allows for more precise automated valve setting.

[0067] If step S1 has taken place, the packing sector 9 is fixed to the reference support 10. This allows the packing sector to be stabilized and moved in a controlled manner during step S8. In particular, the movement of the support, and therefore of the sector, can be controlled during rotations prior to image acquisition, or the movement of the support can be controlled during the installation of the vent valves. This allows these operations to be carried out more stably and results in better performance.

[0068] When all the orifices to be filled are filled with a valve of suitable size, step S8 ends.

[0069] It should be noted that the use of a reference support, since it allows the positions and orientations of the sector's orifices to be referenced relative to the support, makes it possible to perform the data acquisition in the acquisition station and then the installation in a different installation station, while retaining the benefit of the measurements. This makes it possible to increase the production rate of the packing sectors whose orifices are filled with valves; it is indeed possible to simultaneously perform valve installation on one packing sector in the acquisition station and acquisition of geometric data on another packing sector in the acquisition station.

[0070] During an optional ninth step S9, the valve installation can be checked.

[0071] This step S9 can be carried out by an operator.

[0072] Alternatively, this step S9 can be implemented by performing steps S2, S3, and S4 on the packing sector 9 once it has been filled with the vent valves. If all the orifices have been correctly filled with a valve, a new orifice detection in the mapping will not result in any new orifices being detected.

[0073] Another way to implement step S9 is to perform steps S2 and S3 and then check the geometry of the packing sector 9 at each orifice filled during step S8. By comparing the new map and the previous map, it is possible to verify for each orifice whether a valve has been inserted correctly and, if so, to what depth.

[0074] For these last two methods, and since the acquisition station is different from the laying station, this step S9 involves moving the trim sector from the laying station 16 to the acquisition station 3.

Claims

Demands

1. A method for installing vent valves (24) in a lining sector (9) of a tire mold, the method comprising the following steps: - (S1) fixing the sector (9) to a mounting bracket (10), - (S2) acquiring images of the sector (9) from different viewing angles of the sector (9), the acquisition being carried out in an acquisition station (3), - (S3) generating a three-dimensional map of the sector (9) from the images, - (S4) identifying vent valve (24) ports in the sector (9) using the map, the port identification including referencing the port positions relative to the bracket (10), - (S7) moving the bracket (10) to a placement station (16) different from the acquisition station (3), and - (S8) installing a vent valve (24) in each port, the installation being carried out in the pose (16).

2. Method according to claim 1 further comprising a step (S5) of determining for each orifice the orientation of the orifice, the placement of the vent valve taking into account the orientation of the orifice.

3. A method according to any one of claims 1 or 2 wherein the identification of the orifices comprises a step of detecting a cylindrical shape in the mapping.

4. A method according to claim 3 wherein the determination for each orifice of an orifice diameter includes a step of adjusting the cylindrical shape so that the cylindrical shape passes through a maximum of mapping points.

5. A method according to any one of claims 1 to 4 wherein the identification step (S4) in the vent valve orifice sector comprises determining for each orifice an orifice diameter, the method comprising a determination step (S6) for determining for each orifice a vent valve size suitable for the orifice, the valve size being part of a set of valve sizes, the installation step (S8) being configured to install in each orifice a vent valve having the size suitable for the orifice.

6. Method according to claim 5 comprising a data transmission step from the acquisition station (3) to the laying station (16).

7. A method according to any one of claims 1 to 6 comprising a step (S9) of verifying the installation of the valves.

8. A method according to any one of claims 1 to 7 wherein the image acquisition step (S2) comprises several rotations of the sector relative to a camera (5), a number of rotations being greater than or equal to four.

9. Device for placing (1) vent valves (24) in a lining sector (9) of a tire mold, the device (1) comprising: - a mounting support (10) for the lining sector (9), - an acquisition station (3) comprising a camera (5), - a base (12) configured to receive the lining sector (9) and to move the lining sector (9) relative to the camera, - a processor (14) configured to generate a three-dimensional map of the sector from images of the sector, to identify vent valve orifices in the sector using the map, - an installation station (16) comprising an apparatus controlled to place a vent valve in each orifice, and - a conveyor configured to move the support from the acquisition station to the installation station.

Images