ITMO20100053A1 - FAN INSERT FOR ABRASIVE TOOLS. - Google Patents

Description

"FAN INSERT FOR ABRASIVE TOOLS".

DESCRIPTION

The present invention relates to a ventilating insert for abrasive tools intended to be installed on grinding machines.

There are various types of abrasive tools intended to be installed on portable machines. The most common among them are: grinding wheels for deburring and abrasive cutting discs with resin bond, for example at high speed to be used on portable grinders with diameters ranging from 100 to 230 mm, flap discs, discs with scotch brite, fiber discs, etc. .

All these tools have in common the fact that they are installed on a grinding or polishing machine and are rotated in order to exert their abrading or cutting action.

An abrasive grinding wheel, for example, for deburring consists of a disc made from a mixture of abrasive grains, binder resins and fillers which, mounted on a special grinding machine, commonly called a grinder, is rotated around its own axis and then is placed in contact with the piece to be ground, or vice versa.

In order to carry out the assembly of the grinding wheel, grinding machines are normally equipped with a rotating shaft, provided with a centering, a stop shoulder as well as a thread at the free end and two clamping flanges.

One of these two flanges is inserted on the shaft of the grinder and engages on the shoulder and centering of the same. The other flange, on the other hand, has a central threaded hole and is screwed onto the shaft. The grinding wheel, in working conditions, is interposed between these two flanges and is firmly fixed to them by screwing the threaded flange onto the grinder shaft with a certain force. Finally, the grinding wheel is held concentric to the shaft by means of two centering projections obtained on the faces of the flanges which are in direct contact with the grinding wheel. These protrusions enter the central hole of the grinding wheel for a few millimeters and ensure perfect centering.

The deburring wheels can have various shapes of the section which are codified by the EN12413 standard; the most common are the flat and the depressed center ones, but there are also cone or rounded ones. However, all are mounted on the grinders in a manner substantially similar to that described above.

Discoid type abrasive wheels with depressed center or flat are known, described in detail in patent no. 1,361,563 comprising a disc-shaped abrasive and / or cutting element that can be coaxially associated with the free end of the rotating shaft of a grinding machine and provided with a substantially central through hole, with a first face which can be positioned, in the mounting configuration, substantially facing the machine and in contact with a supporting flange of the machine itself, and of a second face opposite to the first face.

Where, a threaded ring nut for attachment to the free end of the rotating shaft which is integral with the substantially central portion of the second face.

These abrasive deburring wheels are essentially constituted by an abrasive mixture reinforced by reinforcements consisting of one or more fabric nets, by one or two possible annular metal or plastic elements, commonly called washers or ring nuts, which delimit the attachment hole of the grinding wheel to the grinder pin and a possible paper label, adhering to one of the two faces of the grinding wheel (usually the convex one).

The abrasive mixture is generally made up of grains of abrasive material (silicon carbide, corundum, modified zirconium corundum, and others) of predefined granulometry (normally measured in Mesh) which are mixed with resins and some additives. The resins are generally phenolic based, liquid and / or powder. Eventually they can be modified with rubbers, epoxy resins and / or others, or with organic and / or vegetable or synthetic compounds.

The reinforcement nets have the purpose of reinforcing the structure of the grinding wheel and allowing it to be used at high rotation speeds in total safety. The high rotation speed is desired as the abrading action is faster and the work is done more quickly. However, high speeds lead to high centrifugal forces and high stress states inside the wheel body. In order to withstand these high tensions, these reinforcing nets are therefore used, made of materials with high breaking load. Generally these nets are woven with glass fiber yarns, but other types of high-strength fibers such as carbon, Kevlar or other can also be used; these nets, usually, before being used inside the grinding wheels are pre-impregnated with resin normally of the same type as that used in the abrasive mixture. This operation has the purpose of obtaining a better adhesion between the yarn of the net and the abrasive mixture itself, thus increasing the resistance of the product. Finally, the nets are punched to obtain a convenient shape (usually round) in order to be placed inside the grinding wheel.

The labels are normally made of paper but also foil or other synthetic material, have the shape of a circular crown, and report the identification and information data of the grinding wheel.

These known types of grinding wheels, however, are not free from drawbacks including the fact that during the deburring operation the friction between the grinding wheel itself and the workpiece generates a considerable amount of heat which leads to overheating both of the workpiece and of the grinding wheel.

This overheating can reach temperatures so high as to lead to the decomposition of the resin of which the wheel itself is composed. The resin thus loses its resistance and causes the release of the abrasive grains and, therefore, the wear of the wheel itself. Furthermore, the above-mentioned overheating can also be harmful to the workpiece as it leads to deleterious effects of various types such as: - burns and pitting with consequent bluish coloring of the surface of the metal piece, a phenomenon particularly undesirable for stainless steel pieces where the visual aspect is also of particular importance;

- burns in wood or plastic materials;

-colors in low-melting metals or plasitic materials;

- modification of the crystalline structure of the metal in the case of self-hardening steels;

- modification of the chemical-physical characteristics in general for all those materials that do not tolerate high temperatures.

All the above considerations are also valid in the case of flap discs, fiber discs, scotch-brite discs or other abrasive tools.

Flap discs, for example, are composed of a circular support plate on which abrasive cloth flaps are glued. The abrasive cloth is a fabric (usually in cotton or polyester) on which a thin layer of grains of abrasive material is fixed. The grains are fixed by spraying the resin fabric, distributing the abrasive grains over it and finally polymerizing the resin. The slats are obtained from the abrasive cloth by cutting out strips of suitable width and finally cutting the individual slats from the strips. Each lamella is placed on the support plate (already sprinkled with glue or resin) so as to form a lamellar package in the shape of a circular crown.

During the use of the flap disc, as with abrasive wheels, a lot of heat is developed and the temperature of the flaps and the workpiece increases rapidly. At high temperatures, the cotton (or synthetic fiber) of the abrasive cloth burns or melts, and the resin that holds the abrasive grains decomposes. All this involves a consumption of the abrasive material of the flap disc.

Furthermore, the workpiece undergoes the same problems due to the heat described above for the abrasive wheels.

The fiber discs are simply a piece of abrasive cloth (sometimes paper) made in a similar way to the cloth for flap discs but punched to have a circular shape.

The fiber disc is fixed to a support plate (which is in turn fixed to the rotating shaft of the grinder) mainly in two ways:

to. The abrasive cloth on the opposite side to the abrasive part has a Velcro fabric and the support plate has the homologous component for the Velcro. The canvas is therefore simply held to the plate by the action of the Velcro.

b. The fiber disc has a hole in the center that allows the grinder shaft to pass through. A threaded flange screwed to said shaft fixes the fiber disc to the rear support.

In both cases, when the fiber disc is processed it generates heat which decomposes the resin of the abrasive cloth, releasing the abrasive grains and causing wear of the fiber disc itself.

Scotch brite discs are composed of a disc of abrasive material and a support plate. The support plate is generally made of fiberboard or plastic. The disc of abrasive material is instead composed of Scotch brite, that is, a material composed of nylon threads in the matrix of which small abrasive grains are incorporated.

Scotch brite is made by dropping molten nylon threads mixed with abrasive grains on a surface according to a random deposition.

When the wire touches the surface it is already almost solid and retains the shape of a wire. The deposition continues until the desired thickness of the fabric is obtained and the finished product is therefore a sheet of threads arranged in a random and disordered way.

This layer thus obtained is then punched and used in various uses. In the case of interest in this discussion, the scotch brite sheet is punched to have a circular shape and is glued to the support plate.

The plate with scotch brite is perforated in the center and is mounted on the grinders like an abrasive wheel, fixing it between the two flanges, that is the stop flange and the threaded clamping flange.

Also in this case when the scotch brite tool is being processed, the heat developed can melt the nylon of which it is composed, causing the release of abrasive grains without them having worked.

Even scotch brite tools must be used at more limited peripheral speeds than abrasive wheels, otherwise the heat generated would be too high and the nylon would melt immediately. As can be seen, in all the above cases the heat generated by the abrasion action causes more or less rapid wear of the tool and the damaging overheating of the material being processed. The aim of the present invention is to eliminate the aforementioned drawbacks of the known art by providing a ventilating insert which allows to reduce the consumption of abrading material and, therefore, increasing its efficiency and average life time.

Furthermore, another object of the invention is to allow the workpieces to be worked without damaging their finish and aesthetic appearance or altering their chemical-physical characteristics.

Within the scope of this technical aim, another object of the present invention is to present a structure that is simple, relatively easy to implement in practice, safe in use and effective in operation, as well as having a relatively low cost.

This task and these purposes are all achieved by the present ventilating insert for the substantially coaxial fastening of abrasive tools, such as deburring wheels, cutting wheels, fiber discs, scotch brite discs or in any case attributable to an abrasive disc element, at the end free of a rotating shaft of an edger, which includes:

at least one threaded ring nut for attachment to said free end of said rotating shaft, an annular portion of which is integrally associated with said disc-shaped element, said threaded ring comprising a central threaded hole and intended to be arranged substantially coaxial to said disc-shaped element and can be coupled to corresponding threaded means made on said free end of said rotating shaft,

characterized in that it comprises deflector means for at least one cooling fluid of said disc-shaped element associated with said threaded ring nut for the radial thrust of said cooling fluid from the central region to the peripheral region of said disc-shaped element during its rotation.

Further characteristics and advantages of the present invention will become more evident from the detailed description of a preferred, but not exclusive, embodiment of a ventilating insert, illustrated by way of indication, but not of limitation, in the accompanying drawings in which:

Figure 1 is a side sectional view of a detail of an abrasive wheel, according to the invention; Figure 2a is a plan view of the threaded ventilating insert of the grinding wheel of Figure 1 in the variant with curved fins;

figure 2b is a plan view of the threaded ventilating insert of the grinding wheel of figure 1 in the variant with straight fins;

Figure 3 is a side section view of a detail of an alternative embodiment of a grinding wheel with a ventilating insert, according to the invention; Figure 4 is a plan view of the threaded ventilating insert of the grinding wheel of Figure 3;

Figures 5, 6 and 7 are side section views of further alternative embodiments of a ventilating insert according to the invention; can be assembled at will on many conventional abrasive wheels;

figure 8 is a side sectional view of a further alternative embodiment of a ventilating insert, according to the invention;

figure 9 is the sectional view of the fan insert only of figure 8

Figure 10 is a side sectional view of a further alternative embodiment of a ventilating insert, according to the invention;

figure 11 is the sectional view of the fan insert only of figure 10

Figures 12a and 12b respectively show a side sectional view and the plan view of a further alternative embodiment of a ventilating insert, according to the invention;

Figures 13a and 13b respectively show a side sectional view and the plan view of a preferred embodiment of a ventilating insert, according to the invention;

Figures 14 to 14b show two respective alternative embodiments of flat wheels with a ventilating insert, according to the invention, in a clamping configuration on the rotating shaft of a grinding machine;

Figure 15 is a side sectional view of a further alternative embodiment of a grinding wheel with a ventilating insert, according to the invention;

Figures 16a and 16b are respectively a side elevation view and the axonometric view of a further embodiment of a ventilating insert with inclined fins, according to the invention. With particular reference to these figures, the ventilating insert for the substantially coaxial fixing of abrasive tools, such as deburring wheels - which in the drawings have been globally indicated with 1 -, cutting wheels, fiber discs, scotch brite discs or in any case attributable to a discoidal element 2 of the abrasive type, at the free end of a rotating shaft of an edger.

In particular, in the examples shown in the figures reference is made to an abrasive wheel 1 with a depressed or flat center, equipped with a ventilating insert, but it is not excluded, however, that this ventilating insert may be associated for the axial fixing of fibrodisks, scotch brite discs or similar.

The grinding wheel 1 comprises a disc-shaped abrasive element 2 for deburring or also for cutting which can be associated, in a substantially coaxial manner, with the free end 3 of a rotating shaft 4 of a grinding machine.

The disc-shaped element 2 is provided with at least one substantially central through hole 5, with a first face 6 which can be positioned (in assembly configuration) substantially facing the machine and in contact with a support flange 7 of the machine itself.

Furthermore, the disc-shaped element 2 is provided with a second face 8 opposite to the first face 6 and defining the active face of the wheel itself (in the case of a deburring wheel).

The ventilating insert comprises at least one threaded ring nut 9 for attachment to the free end 3 of the rotating shaft 4, an annular portion 10 of which is integrally associated with the disc-shaped element 2, and in particular in the case of the grinding wheel 1 with the substantially central portion 11 of the second face 8. The threaded ring nut 9 comprises a central threaded hole 12, substantially coaxial with the discoidal element 2, which can be coupled to corresponding threaded means 13 made on the free end 3 of the rotating shaft itself.

Particularly, for the purposes of the present invention, the ventilating insert comprises deflector means for at least one cooling fluid of the disc-shaped element 2 associated with the threaded ring nut 9 which impart a radial thrust to the cooling fluid from the central area to the peripheral area of the disc-shaped element 2 while rotating the abrasive wheel 1.

The cooling fluid is generally air, which is sucked in by the deflector means during the rotation of the grinding wheel 1 in a direction substantially parallel to the axis of rotation of the grinding wheel itself, and pushed in a radial direction by the deflector means themselves.

Advantageously, the deflector means comprise a plurality of fins 14 which extend substantially in a radial direction with respect to the threaded ring nut 9 and diverging from each other.

At least a first end 14a of the fins 14 is integrally associated with the threaded ring nut 9.

In the embodiments shown in Figures 1, 2a, 2b, the fins 14 extend radially from the central threaded hole 12 to the outer perimeter edge 15 of the threaded ring 9 and are integrally connected, in the part facing the grinding wheel, for the entire length. longitudinal, to the threaded ring itself.

However, it is not excluded that the second end 14b of each of the fins 14 is substantially cantilevered as shown in Figures 3 to 16 with respect to the threaded ring nut 9.

The fins themselves, in this embodiment, protrude externally from the threaded ring nut itself substantially overhanging the discoidal element 2, for example extending beyond the outer perimeter edge 15 of the threaded ring itself.

This conformation is particularly visible in a preferred embodiment of the ventilating insert shown in Figures 13a and 13b, in which the fins 14 extend radially and externally to the threaded ring nut 9, which has a substantially cylindrical shape.

Each of the fins 14 can comprise a substantially C-curved or spiral longitudinal development defining a flow deviator of the cooling fluid, for example, of the type of a centrifugal fan or the like.

The threaded ring 9 is, for example, applied to the disc-shaped element 2 by interposition of a layer of adhesive material and / or by mechanical interference between a cylindrical section 16 of the threaded ring 9 and the through hole 5. The threaded ring 9 can in any case be dissociated from the disc-shaped element 2 and be coupled to it only when the element 2 is installed on the shaft of the grinding machine simply by screwing it onto it.

This, in any case, prevents the threaded ring 9 from detaching from the disc-shaped element 2 during manipulations while, in use, the mechanical transmission of motion and torque from the rotating shaft 4 to the grinding wheel 1 is ensured by the tightening of the grinding wheel. against the supporting flange 7 of the rotating shaft 4. This threaded connection allows the self-locking coupling between the grinding wheel and the rotating shaft itself, without requiring tightening nuts or similar devices.

In particular, as is known, the threading of the threaded ring 9 is such that, during the rotation of the rotating shaft 4, the couples acting on the grinding wheel 1 tend to make it rotate in the direction of screwing of the threaded ring 9 onto the rotating shaft 4.

The threaded ring 9, in one embodiment, comprises a substantially cup-shaped portion which has a concavity facing the second face 8 of the disc-shaped element 2.

The cup portion surrounds the central threaded hole 12 and is opposed to the annular portion 10.

The fins 14, advantageously, are defined in correspondence with the substantially cup-shaped portion itself and such as to protrude from the bottom thereof.

Advantageously, the fins 14 have a height substantially equal to the depth of the cup portion of the threaded ring nut itself and / or to the height of the cylindrical portion 16.

The fins 14, moreover, in the zone proximal to the central threaded hole have surfaces of mutual connection for the fluid-dynamic optimization of the centrifugal thrust of the cooling fluid.

In a preferred embodiment, shown in figures 13a and 13b, the fins are substantially straight and extend radially over the threaded ring nut 9; between each pair of contiguous fins 14, made cantilevered with respect to the threaded ring 9, the connecting surface between them (which is made on the threaded ring itself) has a substantially frusto-conical generatrix with a longitudinal axis substantially inclined with respect to the rotation axis of the ring thread itself, whose mantle extends oblique, forming a diverging channel, for the entire thickness of the threaded ring nut itself.

This expedient allows to increase the active surface (also in the central area of the threaded ring 9) in the thrust of the cooling fluid of each fin 14 and, therefore, allows to improve the ventilation effect imparted by the rotation of the threaded ring itself.

With this solution it is possible to obtain very high ventilation efficiency.

The fins 14, moreover, can be made in one piece with the threaded ring nut 9 or associated with it integrally by means of fastening members, welded, glued or by mechanical joints.

The discoidal element 2 can have different shapes and dimensions; in the embodiment of the invention illustrated in the figures, for example, the grinding wheel 1 is of the type with a lowered or so-called depressed center, i.e. it has a concavity in correspondence with the central portion of the second face 8, and the threaded ring nut 9 is arranged substantially recessed in the interior of this concave central portion. In this embodiment, the thickness of the disc-shaped element 2 is such as to allow housing inside the through hole 5 of the cylindrical portion 16 of the threaded ring nut 9.

However, it is not excluded that, on the other hand, the disc-shaped element 2 is substantially flat and the threaded ring nut 9 is arranged protruding with respect to the second face 8.

In some cases (cutting discs) it may happen that the thickness of the grinding wheel 1 is particularly limited and does not allow the entire cylindrical portion 16 to be accommodated inside the central threaded hole 12.

In figures 14a and 14b the threaded ring nut 9 comprises at least one cavity 17 in correspondence with the surface of the same affected by the annular portion 10 and extending around the central threaded hole 12, for housing the centering edge of the shaft support flange 7 rotating 4 for the self-centering of the grinding wheel 1 with respect to the rotation axis of the rotating shaft itself.

The threaded ring nut 9, shown for example in Figures 3 to 13 and 15, furthermore, comprises at least one annular flange 18 which is substantially continuous and coaxial to the threaded ring nut 9 for joining the fins themselves, whose external radius is substantially equal to the distance between the second end 14b of each fin 14 and the central rotation axis of the threaded ring 9 and the internal diameter is substantially greater than the diameter of the central threaded hole 12.

In the preferred embodiment, shown in Figures 13a and 13b, the annular ring 18 has at least a reduced radial thickness, that is, the difference between the outer radius and the inner radius thereof is substantially equal to 1 mm.

In this embodiment, moreover, the annular ferrule 18 is associated with the second ends 14b of the fins 14 on the same side in which the first ends 14a are associated with the threaded ferrule 9. The annular ferrule 18 is shaped as a thin ring or polygon of very limited section and aerodynamic shape so as not to disturb the flow of air, it eliminates the possibility that these ventilating inserts get stuck one inside the other in the tracks of the vibrating feeders used for their transport, which would prevent a normal and easy flow of the same.

In a further embodiment, shown in Figures 3 to 12 and in Figure 15, the annular flange 18 is integrally associated with the second ends 14b of the fins 14, on the opposite side with respect to the threaded ring nut 9.

The threaded ring nut 9 also comprises outflow openings 19 for the cooling fluid which are interposed between the threaded ring nut 9 and the annular flange 18 at the outer perimeter edge 15 of the threaded ring 9, or in the peripheral region of the threaded ring itself. , in the area of interposition between the fins 14. The annular flange 18, in this case, allows the refrigeration fluid to be channeled in an optimized way inside the area occupied by the fins 14 and, therefore, to improve the axial flow of the air and consequently its radial outflow.

Figures 7 and 6 show some variants of the flange 18 where it is bent respectively towards the grinding wheel 2 or towards the outside depending on where the flow of coolant is to be directed.

In an embodiment of the grinding wheel 1, not shown in the figures, the annular flange 9, for example, can have a substantially planar portion able to be placed in contact with a corresponding planar surface formed on the disc-shaped element 18 and, therefore, be substantially covered by it. In a further possible embodiment of the grinding wheel 1, it can comprise a plurality of through openings made on the disc-shaped element 2 in correspondence with the substantially central portion thereof for the outflow of the cooling fluid, pushed by the deflector means during the actuation of the grinding wheel in rotation, in correspondence with the first face 6 of the same disc-shaped element.

In a further possible embodiment of the grinding wheel 1 illustrated in Figures 8 and 9, the ventilating insert no longer has a perforated and threaded cylindrical central part, but has a thin central part which can be sandwiched between the grinding wheel 2 and a flange clamping 20 of traditional type.

The fins integrally connected to this thin part extend in a substantially radial direction and can be overhung or not by the annular flange 18. In this case there are no constraints for the type of thread as the clamping flange 20 normally supplied with the grinder.

The threaded ring nut 9 shown in figures 8 and 9 can be free or fixed for example by gluing to the discoidal element 2.

In a further possible embodiment of the grinding wheel 1 illustrated in figures 2b, 12b, 13b the ventilating fins do not develop in a spiral but are straight. This solution is simpler to implement in practice.

In a further possible embodiment of the grinding wheel 1 illustrated in Figures 16 a and 16b the fins 14 are no longer cylindrical (i.e. they do not extend in height in a direction parallel to the axis of rotation of the grinding wheel 1) but are oblique. This solution, although complex in practice, is closer to the geometry of centrifugal compressors and can increase the fan effect. The inclined position of the fin 14, in fact, improves the angle of attack of the refrigerant fluid which enters in the axial direction inside the ventilating insert and is pushed by it in the radial direction. Also in this case the insert may or may not be equipped with an annular ring nut 18 for channeling the fluid in the most peripheral area of the insert itself.

The ventilating insert will be able to occupy the entire concavity of these depressed center grinding wheels since the higher the fins 14 are, and therefore the depression is exploited, the more the ventilation efficiency increases. For this purpose, the fins 14 may also protrude from the side of the grinding wheel 1 for a few millimeters and in any case always to the limit of not generating contact problems on the pieces that are being worked when operating with the grinding wheel slightly inclined or almost flat.

The fins can have the most convenient desired height.

In depressed center grinding wheels 1 having deeper concavities the problem of making the fins face out from the side of the grinding wheel does not exist, since the cavity is more than sufficiently deep to determine fins 14 of sufficient height.

These fins 14 can then be as many as desired, from a minimum of 2, and up to the desired efficiency. Their thickness is, too, at will, they can be radially oriented as well as deflected in any shape of a curvilinear type in the left and right direction. They can be straight as well as inclined, of constant or variable inclination, of any angle.

Their external diameter can be of any size, limited only by the fact that they do not interfere with the product to be worked. The application of these inserts can also be carried out on flat wheels, where evidently the ventilating insert must face the side of the wheel. Furthermore, the ventilating insert on the flat grinding wheel could be mounted on both sides of the grinding wheels if necessary. These ventilating inserts can be made of both plastic and metal materials. They can be applied on the grinding wheel both by gluing as by die-casting or by pressing on the wheel itself. They can be pre-threaded in the center as threaded in succession to their assembly as well as not threaded at all.

In practice it has been found that the described invention achieves the intended aim and objects and in particular it is emphasized that the ventilating insert, according to the invention, allows to reduce the wear of the abrasive tool and, therefore, to increase the efficiency and the time. average life of the wheels themselves (either flap discs or fibrodisks or scotch brite discs). Furthermore, the grinding wheel according to the invention, therefore equipped with a ventilating insert, allows the workpieces to be processed without damaging their aesthetic finish or modifying their chemical-physical characteristics.

The invention thus conceived is susceptible of numerous modifications and variations, all of which are within the scope of the inventive concept.

Furthermore, all the details can be replaced by other technically equivalent elements.

In practice, the materials used, as well as the contingent shapes and dimensions, may be any according to requirements without thereby abandoning the scope of the protection of the following claims.

Claims (1)

CLAIMS 1) Ventilating insert for the substantially coaxial fixing of abrasive tools, such as deburring wheels, cutting wheels, fiber discs, scotch brite discs or in any case attributable to an abrasive disc (2) element, at the free end (3) of a rotating shaft (4) of a grinding machine, which comprises: at least one threaded ring nut (9) for attachment to said free end (3) of said rotating shaft (4), one of which annular portion (10) is integrally associated with said disc-shaped element (2), said threaded ring nut (9) comprising a central threaded hole (12) and intended to be arranged substantially coaxial to said disc-shaped element (2) and can be coupled to corresponding threaded means (13) made on said free end ( 3) of said rotating shaft (4), characterized in that it comprises deflector means for at least one cooling fluid of said discoidal element (2) associated with said threaded ring nut (9) for the radial thrust of said cooling fluid cooling from the central area to the peripheral area of said discoidal element (2) during its rotation. 2) Insert according to claim 1, characterized in that said deflector means comprise a plurality of fins (14) extending substantially radially and diverging from each other, at least a first end (14a) of said fins (14) being integrally associated with said threaded ring nut (9). 3) Insert according to claim 1 or 2, characterized in that each of said fins (14) comprises a substantially straight longitudinal development extending radially with respect to said threaded ring nut (9). 4) Insert according to claim 1 or 2, characterized in that each of said fins (14) comprises a substantially C-curved longitudinal development defining a flow deviator for said cooling fluid. 5) Insert according to one or more of the preceding claims, characterized in that said threaded ring nut (9 comprises a substantially cup-shaped portion, surrounding said central threaded hole (12) and opposite to said annular portion (10), said fins (14 ) being defined in correspondence with said substantially cup-shaped portion. 6) Insert according to one or more of the preceding claims, characterized in that the second end (14b) of each of said fins (14) is substantially cantilevered with respect to said threaded ring nut (9). 7) Insert according to one or more of the preceding claims, characterized in that it comprises at least one annular flange (18) which is substantially continuous and coaxial to said threaded ring nut (9) - connecting said fins (14) -, whose external radius is substantially equal to the distance between the second ends (14b) of said fins (14) and the rotation axis of said threaded ring nut (9) and the internal diameter is substantially greater than said central threaded hole (12), said annular flange (18 ) being integrally associated with said second ends (14b) of said fins (14). 8) Insert according to one or more of the preceding claims, characterized in that the connecting surface between each pair of said contiguous fins (14), made in said threaded ring nut (9), has a substantially frusto-conical generatrix in the proximal area with longitudinal axis substantially inclined with respect to the rotation axis of the threaded ring nut itself. 9) Insert according to one or more of the preceding claims, characterized in that it comprises through openings made on said disc-shaped element (2) in correspondence with said substantially central portion thereof for the outflow of said cooling fluid at the back of said discoidal element (2).