Ventilation device for an abrasive wheel and abrasive wheel comprising such a ventilation device

Abstract

The invention relates to a ventilation device for an abrasive wheel, the abrasive wheel (4) comprising a hollow circular body, a hub intended to be attached to a drive motor shaft, the circular body comprising an abrasive outer surface (6) comprising openings (7), an inner surface (8) and an inner space defined by the inner surface (8), the ventilation device comprising an annular body (21) and at least one blade (3) that is arranged radially with respect to the annular body (21), the ventilation device (1) being capable of being located within the inner space of the abrasive wheel (4) and the annular body (21) being capable of being rigidly attached to the hub of the abrasive wheel (4) or to the circular body at the periphery of the hub of the abrasive wheel (4).

Description

[0001] The present invention relates to a ventilation device for an abrasive wheel and an abrasive wheel comprising such a ventilation device, more specifically an abrasive wheel for tire retreading.

[0002] Recurring problems in the field of surface abrasion, particularly on rubberized surfaces, especially during tire retreading operations, include the formation of significant heat by friction at the surface to be abraded, the risk of ignition of the abraded particles, and the accumulation of abraded particles in the abrasive material, rendering the grinding wheel unusable.

[0003] Excessive temperature rise of the abraded surface alters the surface condition of the rubber, which leads to a qualitative decrease in the results of repair operations or the installation of a new tread.

[0004] The rising temperature of the abraded particles, which become soft and sticky, makes it more difficult for them to be removed by centrifugal force. These particles tend to accumulate in the abrasive grain of the grinding wheel, literally clogging the abrasive surface, making it smooth and ineffective.

[0005] The grinding wheels are thus changed prematurely, before the abrasive grain is completely worn, because the abrasive surface is saturated with abraded particles. The abrasive surface is therefore no longer sufficiently effective and causes the surface being abraded to overheat too quickly, potentially leading to fires.

[0006] An abrasive wheel is commonly formed of a circular body equipped with a hub in its center, the outer periphery of the circular body is extended by a rim arranged perpendicularly to the circular body, the outer surface of the rim of which is covered with an abrasive material.

[0007] To increase airflow inside the grinding wheel, openings are made in the circular body, creating an air intake through these openings and an air exhaust towards the open part of the grinding wheel, in the direction of the wheel drive axis.

[0008] To limit the accumulation of abraded particles in the abrasive grain of the grinding wheel, and to theoretically provide airflow towards the surface to be abraded, orifices have been made in the abrasive surface.

[0009] However, the air intake from the circular body of the grinding wheel is not directed towards the inner surface of the rim, opposite the abrasive surface.

[0010] In practical terms, the airflow inside the grinding wheel does not actually help to cool either the abrasive surface or the surface to be abraded.

[0011] The holes arranged in the edge of the grinding wheel do not, by themselves, carry enough abraded particles inside the grinding wheel to limit the fouling of the abrasive surface.

[0012] Furthermore, the fouling of the abrasive surface is due to hot and sticky particles; the presence of holes on the abrasive surface does not prevent their agglomeration.

[0013] Numerous developments have been proposed in modifying the orifices of the abrasive edge, such as documents US 3,406,489, US 3,579,928, US 3,916,579, but do not appear to help resolve the problems mentioned above.

[0014] Document WO2018 / 177541 proposes to direct the airflow inside the grinding wheel towards the lower surface of the rim, by creating cutouts in the circular body of the grinding wheel, consisting of openings and the counterparts of these openings forming tabs folded inwards.

[0015] Document WO 2021 / 037055 discloses a water cooling device comprising an annular body and at least one blade arranged radially with respect to the annular body. However, the blades of the cooling device are fixed to the periphery of the grinding wheel hub. More precisely, the blades are connected to the grinding wheel by screws passing through holes arranged on the blades. Thus, the hub / annular body of the cooling device described in the document is not suitable for being fixed to the grinding wheel hub.

[0016] The sizing of these tabs is limited by the circular body of the abrasive wheel, and does not appear sufficient to create airflow turbulence that can be directed towards the surface to be abraded.

[0017] The present invention proposes a set of ventilation devices integrated into an abrasive wheel, making it possible to create significant airflows capable of cooling the abrasive surface and the surface to be abraded, thus overcoming the aforementioned drawbacks.

[0018] Thus, the ventilation device according to the invention, for an abrasive wheel comprising a hollow circular body, a hub intended to be fixed to a drive shaft, the circular body comprising an abrasive outer surface including orifices, an inner surface and an inner space delimited by the inner surface, the ventilation device comprising an annular body and at least one blade arranged radially with respect to the annular body, the ventilation device being able to be located in the inner space of the abrasive wheel and the annular body being able to be fixed securely to the hub of the abrasive wheel or to the circular body at the periphery of the hub of the abrasive wheel, characterized in that the outer periphery of the at least one blade is able to be located in the vicinity of the inner surface opposite the abrasive outer surface of an abrasive wheel.

[0019] According to one characteristic, the ventilation device is capable of occupying substantially the entire internal space of an abrasive grinding wheel.

[0020] According to an additional feature, the ventilation device is capable of creating airflows that create turbulent zones as close as possible to the inner surface opposite the outer abrasive surface of a grinding wheel.

[0021] According to some embodiments, at least one blade has a shape suitable for creating an air suction flow from the inner surface to the inner space of the abrasive wheel.

[0022] According to embodiments, at least one blade has a shape suitable for creating an airflow directed towards the inner surface and being expelled through the orifices of the abrasive wheel.

[0023] The invention also relates to an abrasive grinding wheel comprising a hollow circular body, a hub suitable for being fixed to a drive motor shaft, the circular body comprising an abrasive outer surface which includes orifices and an inner surface, the circular body comprising an inner space delimited by the inner surface, characterized in that it includes the ventilation device according to the invention.

[0024] According to one characteristic, at least one blade is located at a distance greater than 0.3 millimeters from the inner surface of the abrasive wheel.

[0025] According to some embodiments, the hollow circular body comprises a central circular wall in line with the hub, bordered by a rim perpendicular to the central circular wall, commonly called an abrasive wheel.

[0026] According to some embodiments, the abrasive wheel comprises two hollow circular bodies assembled together, each comprising a semi-toric wall forming a torus, commonly called a donut.

[0027] The implementation of the invention will be better understood with the aid of the detailed description set forth below, in conjunction with the accompanying drawings, in which:

[0028] THE figures 1 à 3 illustrate a ventilation device and an abrasive wheel according to an embodiment of the invention. [ Fig 1 ] is a perspective view of a ventilation device assembled with an abrasive wheel. Fig 2 ] is a front view of the figure 1 . [ Fig 3 ] is a perspective view of the ventilation system of the figure 1 . THE figures 4 et 5 illustrate a ventilation device and an abrasive wheel according to another embodiment of the invention. Fig 4 ] is a perspective view of the ventilation device assembled to an abrasive wheel. Fig 5 ] is a side view of the ventilation system of the figure 4 . THE figures 6 à 8 illustrate a ventilation device and an abrasive donut according to one embodiment of the invention. Fig 6 ] is an exploded perspective view of a ventilation device and an abrasive donut. Fig 7 ] is an assembled perspective view of the figure 6 . [ Fig 8 ] is a perspective view of the ventilation system of the figure 6 . THE figures 9 And 10 illustrate a ventilation device and an abrasive dome according to another embodiment of the invention. Fig 9 ] is an exploded perspective view of a ventilation device and an abrasive dome. Fig 10 ] is an assembled front view of the figure 9 . THE figures 11 And 12illustrate a ventilation device and an abrasive wheel according to one embodiment of the invention. Fig 11 ] is a perspective view of a ventilation device assembled with an abrasive wheel. Fig 12 ] is a perspective view of the ventilation system of the figure 11 . [ Fig 13 ] illustrates temperature measurements of the outer surface of the abrasive wheel in action, as a function of time, during an abrasion operation on the outer surface of a tire with an abrasive wheel and a ventilation device as illustrated in the figure 11 , as well as with an abrasive wheel without the ventilation device.

[0029] The ventilation device (1) according to the invention is an independent part intended to be attached to an abrasive grinding wheel (4).

[0030] A circular abrasive wheel (4) commonly comes in the form of a wheel, a torus or a dome, as explained in more detail later in the description.

[0031] The ventilation device (1) is intended to cool the outer abrasive surface (6) and the substrate to be ground, to contribute to the evacuation of abraded particles generated by the grinding process and to the cleaning of the grinding wheel, both inside the abrasive wheel (4) and to limit or even drastically reduce the fouling of the outer abrasive surface (6) by the abraded particles.

[0032] During abrasion operations with the ventilation device (1) according to the invention, the abraded particles, instead of gradually rising in temperature and agglomerating in the abrasive outer surface (6) of the grinding wheel, are directly subjected to powerful airflows, causing them to cool and harden rapidly.

[0033] The cooled and hard particles can no longer clump together in the abrasive outer surface (6) of the grinding wheel, and are in particular ejected outwards by the rotation of the grinding wheel, as explained in more detail later in the description.

[0034] The ventilation device (1) thus improves the cleanliness of the surface to be abraded and the cleanliness of the grinding wheel as a whole.

[0035] The shape and dimensions of the ventilation device (1) are custom-made according to the shape and dimensions of the abrasive wheel (4) in which it is intended to be secured.

[0036] The ventilation device (1) being fixedly assembled to the abrasive wheel (4), it thus rotates at the same speed as the abrasive wheel (4).

[0037] The airflow generated by the ventilation device (1) inside the abrasive wheel (4) increases as a function of the rotational speed of the drive motor shaft of a machine tool.

[0038] The higher the rotation speed, the more powerful the airflows generated will be, proportionally compensating for the heating of the abrasive wheel (4) and the surface to be abraded.

[0039] Even at high rotational speed, the abrasive wheel (4) retains a cooling capacity of the working surface and cleaning of the interstitial spaces between the abrasive grains.

[0040] A machine tool may be a portable electric machine for abrasive grinding wheels (4) in the form of a wheel, dome or donut, or a stationary workshop machine for abrasive grinding wheels (4) in the form of a wheel or donut.

[0041] It is understood that the wheels and donuts mounted on a stationary machine have larger dimensions and a predominantly higher rotational speed than those mounted on a portable electric machine.

[0042] An abrasive grinding wheel (4) may be open as in the case of a wheel or dome, or closed as in the frame of a torus commonly called a donut.

[0043] It is understood that a torus is an open torus, resembling an inner tube.

[0044] An abrasive grinding wheel (4) thus comprises a hollow circular body with a hub (5) in its center suitable for being connected to a drive shaft of a machine tool.

[0045] The circular body is represented by a single wall of revolution in the case of a wheel or a dome and by two walls of revolution assembled in opposition for a donut.

[0046] It is understood that the circular body is centered on the periphery of the hub (5).

[0047] The hub (5) consists of a discoidal part with a circular opening designed to fit around the drive shaft of a machine tool.

[0048] A wall of revolution of an abrasive wheel includes a circular central wall (10) and a rim (11) located perpendicularly to the outer periphery of the circular central wall (10).

[0049] The central circular wall (10) can be confused with or assimilated to the discoidal part of the hub (5).

[0050] The circular central wall (10) may include a depression extending from the outer periphery of the discoidal portion of the hub (5) to the base of the rim (11), as illustrated in the figure 1 , but it could be otherwise, a central circular wall (10) is flat.

[0051] A wall of revolution of a dome open at its base comprises an elliptical wall whose apex includes a circular portion advantageously provided with a depression directed towards the interior space of the dome. The circular portion includes at its center a discoidal portion comprising an opening, the discoidal portion and the opening constituting the hub (5), as illustrated in the figure 9 .

[0052] A wall of revolution of a donut comprises a central circular wall (10) formed by the discoidal part of the hub (5), and a semi-toric wall (12) located at the outer periphery of the central circular wall (10), as illustrated in the figure 6 .

[0053] The wall of revolution includes orifices (7) on the abrasive outer surface (6) and advantageously on the circular central wall (10), advantageously distributed in a regular manner.

[0054] The orifices (7) located on the abrasive outer surface (6) are all the more essential in the context of the present invention, since they allow the large airflows generated by the ventilation device (1) to be conducted, as explained in more detail in the rest of the description.

[0055] The holes (7) in the abrasive outer surface (6) can be of any shape, such as grooves, circular or hexagonal holes, regularly distributed over the abrasive outer surface (6).

[0056] The greater the proportion of orifices (7), the more effective the cooling of the outer abrasive surface (6) and the surface of the substrate to be abraded will be.

[0057] However, the higher the proportion of orifice (7), the lower the effective abrasion surface of the grinding wheel.

[0058] The ratio between the proportion of orifices (7) and the effective abrasion surface must be modulated, according to the application chosen, for example a ratio of one third.

[0059] The wall of revolution comprises an outer surface and an inner surface (8).

[0060] The outer surface of the wall of revolution includes at least one part which comprises an abrasive material.

[0061] In the case of an abrasive wheel, the outer surface of the rim (11) comprises an abrasive material.

[0062] In the case of a dome or a donut, substantially the entire outer surface of the wall of revolution comprises an abrasive material.

[0063] The inner surface (8) of the wall of revolution of the hollow circular body defines an inner space (9) in which the ventilation device (1) is able to be housed.

[0064] Thus, the ventilation device (1) comprises an annular body (21, 22) and at least one blade (3) arranged radially with respect to the annular body (21, 22).

[0065] The annular body (21, 22) includes an outer circumference from which the blades (3) extend outwards.

[0066] The ventilation device (1) is intended to be attached coaxially to the abrasive wheel (4).

[0067] According to a first alternative, the annular body (21, 22) is a central hub (21), as illustrated in figures 1 à 10 The central hub (21) is suitable for being secured to the hub (5) of the abrasive wheel (4), as explained in more detail later in the description.

[0068] According to a second alternative, the annular body (21, 22) is a ring (22), as illustrated in figures 11 And 12The ring (22) is suitable for being secured to the central circular wall (10) on the periphery of the hub (5) of the abrasive wheel (4), as explained in more detail later in the description.

[0069] The central hub (21) described in the embodiments illustrated in figures 1 à 10 , is interchangeable by the ring (22) without going out of the scope of the invention.

[0070] Note that the annular body (21, 22) can be in one piece, as represented in the illustrated embodiments, or be composed of several arc-shaped portions whose assembly to an abrasive wheel (4) forms an annular body (21, 22), but it could be otherwise the annular body (21, 22) is composed of an assembly of straight portions whose general shape assembled to an abrasive wheel (4) forms a regular polygon possessing a rotation of order n, such as a hexagon, an octagon, etc.

[0071] The number of blades (3) and their distribution around the annular body (21, 22) must of course be balanced, so that the rotation of the assembly formed by the abrasive wheel (4) and the ventilation device (1) is stabilized and homogeneous.

[0072] The ventilation device (1) may include two, three, four, five or more blades (3), or a single blade (1) for example in the shape of a skirt, not illustrated.

[0073] THE figures 4 And 9 illustrate ventilation devices (1) comprising five blades, the figure 1 illustrates a ventilation device (1) comprising six blades, the figure 6 illustrates a ventilation device (1) comprising twelve blades, and the figures 11 And 12 illustrate a ventilation device (1) comprising 16 blades.

[0074] The central hub (21) is intended to be fitted around the drive shaft of a machine tool, and to be fixed to the hub (5) of the abrasive wheel (4).

[0075] The ring (22) is intended to be fixed securely, for example by welding or riveting to the central circular wall (10) on the periphery of the hub (5) of the abrasive wheel (4), coaxially with the drive shaft of a machine tool.

[0076] Since the rotational speed of the drive shaft and the weight of the abrasive wheel (4) are significant, it is understood that the secure attachment of the ventilation device (1) to the abrasive wheel (4) must be achieved without play.

[0077] It is therefore imperative that any untimely vibration of the assembly consisting of the abrasive wheel (4) and the ventilation device (1) around the motor shaft be avoided.

[0078] The central hub (21) of the ventilation device (1) can be fixed to the hub (5) of the abrasive wheel (4) by mechanical connection, by welding or by gluing.

[0079] The mechanical connection of the hub (5) of the abrasive wheel (4) and the central hub (21) of the ventilation device (1) to the drive motor shaft can be achieved by any means known in the field of fixing a hub to a motor shaft, such as with a coupling adapter also called a hub-shaft locking device, for example a threaded shaft and a nut, or the combination of keys and grooves, or pins, etc.

[0080] It is also conceivable that the central hub (21) of the ventilation device (1) includes a sleeve that fits into the hub (5) of the abrasive wheel (4) and is fitted around the drive motor shaft, as illustrated in the figure 10 . Rotational guidance is achieved, for example, by combining bores and ribs or keys, not shown.

[0081] The central hub (21) includes a discoidal part whose inner periphery delimits the opening intended to be fitted around the drive motor shaft, and whose outer periphery extends into blades (3) or is connected to blades (3).

[0082] Any shape of blade (3) located in the interior space (8) of the circular body of the abrasive wheel (4) will create an airflow inside the wheel, when the assembly formed by the abrasive wheel (4) and the ventilation device (1) rotates.

[0083] However, in order to cool the abrasive surface and the surface to be abraded, the periphery of a blade (3) needs to be close, advantageously as close as possible, to the inner surface (8) located opposite the outer abrasive surface (6) of the abrasive wheel (4).

[0084] According to embodiments not shown, the ventilation device (1) is able to extend throughout the entire interior space (9) of the abrasive wheel (4).

[0085] According to the preceding embodiments, the blades (3) extend to the inner surface (8) located opposite the outer abrasive surface (6), namely are in contact with the inner surface (8) of the abrasive wheel (4).

[0086] According to some embodiments, the ventilation device (1) is able to extend substantially throughout the entire interior space (9) of the abrasive wheel (4).

[0087] According to the preceding embodiments, at least a part of the periphery of a blade (3) is located in the vicinity of at least a part of the inner surface (8) located opposite the abrasive outer surface (6).

[0088] In order to optimize the internal airflow of the grinding wheel and to support concentric air circulation on the inner wall of the grinding wheel and to avoid any deposition of particles on the inner wall of the grinding wheel and between a blade (3) and the inner surface (8) of the abrasive wheel (4), it is recommended that the distance between the blades (3) and the inner surface (8) be greater than or equal to three times the average size of the abraded particles.

[0089] The average size of the abraded particles is dependent on the size of the abrasive grains on the abrasive surface, and is on the order of 0.1 to 1 millimeters.

[0090] According to a complementary feature, the outer periphery of a blade (3) located opposite the inner surface (8) arranged in opposition to the abrasive outer surface (6), is located at a distance greater than or equal to 0.3 millimeters, advantageously remaining close, namely in the vicinity of the inner surface (8).

[0091] The outer periphery of a blade (3) is understood to be the end or tip of the blade (3) located furthest from the annular body (21, 22).

[0092] Proximity to the inner surface (8) is understood to mean a distance between 0.3 millimeters and 70%, preferably 50%, more preferably 30% of the radius of the abrasive wheel, or the radius of the base of a dome, or the diameter of the torus of a donut, depending on the required use and the diameter of the abrasive wheel (4).

[0093] According to one feature, the outer periphery of a blade (3) located opposite the inner surface (8) arranged opposite the outer abrasive surface (6), is located at a distance less than or equal to 70%, preferably 50%, more preferably 30% of the radius of the abrasive wheel, or the radius of the base of a dome, or the diameter of the torus of a donut.

[0094] Preferably, the outer periphery of a blade (3) located opposite the inner surface (8) arranged in opposition to the outer abrasive surface (6), is located at a distance less than or equal to 50% of the radius of the abrasive wheel, or the radius of the base of a dome, or the diameter of the torus of a donut.

[0095] More preferably, the outer periphery of a blade (3) located opposite the inner surface (8) arranged in opposition to the outer abrasive surface (6), is located at a distance less than or equal to 30% of the radius of the abrasive wheel, or the radius of the base of a dome, or the diameter of the torus of a donut.

[0096] According to embodiments, the outer periphery of a blade (3) located opposite the inner surface (8) arranged in opposition to the outer abrasive surface (6), is located at a distance between 0.3 millimeters and 70%, preferably 50%, more preferably 30% of the radius of the abrasive wheel.

[0097] According to embodiments, the outer periphery of a blade (3) located opposite the inner surface (8) arranged opposite the abrasive outer surface (6), is located at a distance between 0.3 millimeters and 70%, preferably 50%, more preferably 30% of the radius of the base of a dome.

[0098] According to embodiments, the outer periphery of a blade (3) located opposite the inner surface (8) arranged opposite the abrasive outer surface (6), is located at a distance between 0.3 millimeters and 70%, preferably 50%, more preferably 30% of the diameter of the torus of a donut.

[0099] The general profile of the ventilation device (1) may be flat or include a depression at the periphery of the annular body (21, 22) in order to adapt to the possible depression of the circular central wall (10) of the abrasive wheel (4). The possible depression of the ventilation device (1) is defined by the profile of the blades (3).

[0100] The orientation and shape of a blade (3) according to the direction of rotation of the abrasive wheel (4) generates air flows either of suction from the outside to the inside of the wheel through the orifices (7) of the abrasive outer surface (6), or of exhaust of air from the inside to the outside of the wheel through the orifices (7) of the abrasive outer surface (6).

[0101] The profile of a blade (3) can be flat or curved.

[0102] A flat blade (3) arranged perpendicular to the axis of rotation of the drive shaft generates, regardless of the direction of rotation of the grinding wheel, airflow from the inside to the outside of the grinding wheel. More precisely, air is drawn in along the axis of rotation of the drive shaft and air is expelled in a direction perpendicular to the axis of rotation of the drive shaft.

[0103] THE figures 6 à 8 , illustrate a donut-shaped abrasive wheel (4) and a ventilation device (1) comprising blades (3) arranged perpendicular to the central hub (21).

[0104] Thus, according to the embodiment illustrated in figures 6 à 8 , the ventilation device (1) includes a central hub (21) consisting of a discoidal part and flat blades (3) arranged perpendicularly to the discoidal part of the central hub (21).

[0105] According to the previous embodiment, the blades (3) are discs welded perpendicularly to the central hub (21).

[0106] According to one embodiment, not illustrated, the abrasive wheel (4) is a dome and the ventilation device (1) comprises a central hub (21) and blades (3) arranged perpendicularly to the central hub (21).

[0107] According to another embodiment, not illustrated, the abrasive wheel (4) is a wheel comprising a depression extending from the outer periphery of the discoidal part of the hub (5) to the base of the rim (11), the ventilation device (1) comprises a central hub (21) and blades (3) arranged perpendicularly to the central hub (21).

[0108] Considering a counterclockwise direction of rotation, a flat blade (3) making an angle with the axis of rotation of the motor shaft, for example 45°, or a curved blade (3), whose leading edge is located in the vicinity of or in contact with the inner surface (8) of the abrasive wheel (4) and whose trailing edge is located in the direction of the opening of the abrasive wheel (4), generates an intake of air from the rear, namely in the direction of the periphery of the hub (5), and an exhaust of air from the front, namely in the direction of the opening of the abrasive wheel (4) in the shape of a dome or wheel, and generates a radial suction phenomenon at the end of the blade (3), namely at the level of the edge (11) of a wheel or at the level of the largest diameter part of a dome.

[0109] According to the embodiment illustrated in figures 9 And 10The abrasive wheel (4) is a dome and the ventilation device (1) comprises flat blades (3) oriented at 45° to the central hub (21). The blades (3) are in the vicinity of the inner surface (8) of the dome, i.e., the blades (3) are not in contact with the inner surface (8) of the abrasive wheel (4).

[0110] According to the execution method illustrated in figures 4 et 5 , the abrasive wheel (4) is a wheel comprising a depression extending from the outer periphery of the discoidal part of the hub (5) to the base of the rim (11), the ventilation device (1) comprises a central hub (21) and curved blades (3) whose profile is designed to fit the depression of the abrasive wheel.

[0111] According to the preceding embodiment, the leading edge of a blade (3) is oriented towards the inner surface (8) of the central part (10), the trailing edge of a blade (3) is oriented towards the opening of the abrasive wheel (4), and the tip of a blade (3) is oriented towards the inner surface (8) of the rim (11).

[0112] According to another embodiment illustrated in figures 1 à 3 , the abrasive wheel (4) is an abrasive wheel comprising a depression extending from the outer periphery of the discoidal part of the hub (5) to the base of the rim (11), the ventilation device (1) comprises a central hub (21) and V-shaped blades (3) oriented in a counterclockwise direction and arranged in the depression of the abrasive wheel (4).

[0113] According to the preceding embodiment, a blade (3) comprises a downward flat part oriented radially with respect to the central hub (21), a flat part parallel to the discoidal part of the central hub (21) and an upward flat part oriented in the counterclockwise direction following the curvature of the periphery of the discoidal part of the central hub (21).

[0114] According to the preceding embodiment, the descending flat portion comprises an opening and a fin, the fin being the counterpart of the opening, which is bent inwards towards the inner surface of the circular central portion (10). This opening and this tab help to direct the airflow along the ascending flat portion. The fins also help to create turbulence at the center of the grinding wheel, preventing the deposition of abrasive particles within the grinding wheel (4), thus promoting its internal cleaning.

[0115] As previously introduced, during an anti-clockwise rotation, the airflow is brought along the upper surface of the rising flat part, generating a radial suction flow of air through the orifices (7) arranged in the border (11).

[0116] According to the embodiment illustrated in figures 11 And 12 , the ventilation device (1) includes a ring (22) whose annular wall extends radially outwards by means of blades (3).

[0117] According to the previous embodiment, a blade (3) is composed of a branch which extends radially in a coplanar manner with respect to the outer circumference of the ring (22), and is extended by a flat wall oriented at 45° with respect to the branch.

[0118] According to the preceding embodiment, the ring (22) includes regularly spaced mounting holes on its annular wall. These mounting holes are suitable for riveting to the circular central wall (10) on the periphery of the hub (5) of the abrasive wheel (4). The circular central wall (10) includes additional mounting holes, not shown, to those of the ventilation device (1).

[0119] Abrasion tests, as illustrated in the figure 13 , of a surface area of ​​a tire were made using an abrasive wheel and the ventilation device (1) conforming to that illustrated in the figure 11 The tests were performed with a control test consisting solely of an abrasive wheel without a ventilation device. These tests involved applying a virtually continuous force for 330 seconds. The temperature of the grinding wheel's outer surface was measured using an infrared thermometer. Temperature measurements were taken at 15-second intervals. The temperature measurements accounted for the difference from ambient temperature, meaning the first measurement was taken at zero degrees Celsius. The pressure exerted by the tool on the tire surface was intentionally maximized, given the machine tool's resistance, to increase friction and temperature. The tire's tread was virtually perforated in several places.

[0120] At the end of the test carried out with the abrasive wheel and the ventilation device (1) conforming to that illustrated in the figure 11 The inside and outside of the abrasive wheel remained perfectly clean, with the outer abrasive surface (6) completely free of abraded particles. The outer abrasive surface (6) was slightly dulled due to the abrasion of the metal threads inside the tire matrix. The tire surface was warm to the touch, which is unusual. Normally, heated abraded particles systematically become embedded in the interstices of the abrasive surface grains.

[0121] Indeed, at the end of the control abrasion test, the abrasive wheel without a ventilation device shows a deposit of abraded particles covering the entire inner surface of the grinding wheel. Although the control test is relatively short compared to real-world use, the abrasive surface of the control wheel still exhibits a significant accumulation of abrasive particles.

[0122] Temperature measurements of the outer surface of the abrasive wheel including the ventilation device (1) conforming to that illustrated in the figure 11 , are almost half as high after 330 seconds as those achieved by the control grinding wheel without a ventilation device.

[0123] For dome or donut-type abrasive wheels, an air evacuation phenomenon from the inside to the outside towards the abrasive outer surface (6) seems preferable, especially for a donut in order to avoid the accumulation of abraded particles inside the toroidal shape of the wheel.

[0124] For abrasive wheels, suction or blowing phenomena of airflow towards the abrasive surface can be used.

[0125] As previously introduced, the temperature rise of the substrate to be abraded makes the particles soft and sticky, causing them to clump together in the interstices of the abrasive outer surface (6), rendering the abrasive wheel (4) unusable.

[0126] Let us recall that the ventilation device (1) according to the invention creates powerful airflows, which allow for a low temperature maintenance of the abraded particles, the abrasive surface and the surface to be abraded.

[0127] In addition to the ejection, by centrifugal force, of the abraded particles towards the outside of the grinding wheel, the aspiration of the abraded particles through the orifices (7) of the outer abrasive surface (6) strongly limits or even prevents the aggregation of these particles in the grains of the outer abrasive surface (6), increasing its service life.

[0128] Furthermore, the creation of airflows blowing towards the inner outer surface (8) of the abrasive wheel (4) by the ventilation device (1) creates a phenomenon of ejection of the abraded particles in contact with the abrasive outer surface (6), which in synergy with the centrifugal force expels the abraded particles, preventing their possible agglomeration in the abrasive outer surface (6).

[0129] The physical wear of abrasive materials appears to be the only limit to the longevity of the assembly formed by the abrasive wheel (4) and the ventilation device (1) according to the invention.

Claims

1. Ventilation device assembly (1) and abrasive wheel, said abrasive wheel (4) comprising a hollow circular body, a hub (5) intended to be fixed to a drive motor shaft, the circular body comprising an abrasive outer surface (6) comprising orifices (7), an inner surface (8) and an inner space (9) delimited by the inner surface (8), the ventilation device (1) comprising an annular body (21, 22) and at least one blade (3) disposed radially with respect to the annular body (21, 22), the ventilation device (1) being capable of being located in the interior space (9) of the abrasive wheel (4) and the annular body (21, 22) being capable of being fixed integrally to the hub (5) of the abrasive wheel (4) or to the circular body at the periphery of the hub (5) of the abrasive wheel (4), characterized in that the outer periphery of the at least one blade (3), is capable of being located in the vicinity of the inner surface (8) opposite the outer abrasive surface (6) of an abrasive wheel (4) .

2. Assembly according to claim 1, characterized in that it is capable of occupying substantially the entire interior space (9) of an abrasive wheel (4).

3. Assembly according to claim 1 or 2, characterized in that it is capable of creating air flows that create areas of turbulence as close as possible to the inner surface (8) opposite the outer abrasive surface (6) of an abrasive wheel (4).

4. Assembly according to any of the preceding claims , characterized in that the at least one blade (3) has a shape capable of creating a suction flow of air from the inner surface (8) towards the interior space (9) of the abrasive wheel (4).

5. Assembly according to any of claims 1 to 3, characterized in that the at least one blade (3) has a shape suitable for creating an air flow directed towards the inner surface (8) and to be expelled through the orifices (7) of the abrasive wheel (4).

6. Abrasive wheel (4) comprising a hollow circular body, a hub (5) capable of being fixed to a drive motor shaft, the circular body comprising an outer abrasive surface (6) which includes orifices (7) and an inner surface (8), the circular body comprising an interior space (9) delimited by the inner surface (8), characterized in that it comprises the ventilation device (1) of the assembly according to any of the preceding claims.

7. Abrasive wheel (4) according to the previous claim, characterized in that the at least one blade (3) is located at a distance greater than 0.3 millimeters from the inner surface (8) of the abrasive wheel (4).

8. Abrasive wheel (4) according to claim 6 or 7, characterized in that the hollow circular body comprises a circular central wall (10) in line with the hub (5), bordered by a rim (11) perpendicular to the circular central wall (10), commonly known as an abrasive wheel.

9. Abrasive wheel (4) according to claim 6 or 7, characterized in that it comprises two hollow circular bodies assembled together, each comprising a semi-toric wall (12) forming a torus, commonly known as a donut.

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