METHOD AND PLANT FOR THE THERMAL TREATMENT OF FRICTION ELEMENTS, IN PARTICULAR BRAKE PADS

Description

Technical Field of the Invention

[0001] The present invention relates to a method and plant for carrying out thermal treatments on friction elements, in particular braking elements such as brake pads.

Prior Art:

[0002] After the completion of the braking element forming step, the friction materials used as seals in the brake shoes of drum brakes and as brake pads in disk brakes for vehicles and other equipment (such as clutch discs) need to undergo a thermal treatment that both enhances the characteristics of said materials and makes it possible to eliminate any residual gases.

[0003] In particular, in the case of brake pads, the pads, upon leaving the forming press, are heated for a certain period of time at temperatures generally slightly higher than 200°C, usually by means of convection ovens.

[0004] The thermal treatment plants commonly in use today include, as a main element, a horizontal or vertical convective oven.

[0005] The vertical ovens (known as "Paternoster" ovens) are provided with a chain conveyor having an ascending arm and a descending arm arranged within an insulated enclosure. The brake pads are arranged on the tray supports, which are individually attached to the chain conveyor, which conveys them within the insulated enclosure, wherein a series of heating zones is arranged that are provided with electrical resistances; when the supports reach the end of the descending arm, the thermal treatment of the brake pads should have been completed, at which point the brake pads are removed and the tray supports are transported to the beginning of the ascending arm to be loaded for a new cycle of work.

[0006] This type of plant is expensive, complicated, and very cumbersome.

[0007] The latter inconvenience, i.e. the large encumbrance, is also present if horizontal convective tunnel ovens are used, such as, for example, in WO2014162282, where the brake pads in order to be submitted also to the IR treatment, must be placed on a conveyor belt that runs within a tunnel oven in the same longitudinal direction as a flow of hot air/gases, which passes through the convective oven from one end to the other of the same.

[0008] Also known from DE202009015250U and DE202012103521U is a method for performing the baking of tiles or other bricks in a conventional oven, where the objects to be baked are arranged on stackable shelves made from a ceramic material.

Summary of the Invention

[0009] The purpose of the present invention is to provide a method and plant for the thermal treatment of friction elements, in particular of braking elements such as brake pads, which allow for the treatment of a large number of braking elements with reduced dimensions and lead times, while ensuring optimal adhesion of the actual thermal cycle implemented by the plant to that envisaged during the design phase.

[0010] The invention is thus related to a method and plant for carrying out thermal treatments of friction elements, especially braking elements such as brake pads, having the characteristics set out in the attached claims.

[0011] The plant of the invention can be arranged immediately downstream of a forming step of braking elements and allows for the uniform heating at the same temperature of all of the braking elements treated. It also allows for continuous thermal treatment. Finally, braking elements treated using the method and plant of the invention have surprisingly been shown to have better performance than the same braking elements treated using traditional methods or plants.

[0012] In particular, a notable increase in productivity is obtained compared to prior art ovens. In addition, given that the method of the invention includes the arrangement of the braking elements on independent trays, said trays can be stored and managed within the oven thereby maximizing the filing of the entire available volume. Finally the method and plant of the invention are more efficient than the "paternoster" oven, especially when high output volumes are required. Another advantage is that, as mentioned above, the temperature measured on the brake pads treated with the plant of the invention are very accurate, stable and repeatable compared to those that can be measured on the same pads treated with prior art ovens.

Brief Description of the Drawings

[0013] Further characteristics and advantages of the present invention will become clear from the following description of an exemplary non-limiting embodiment given purely by way of example and with reference to the figures within the accompanying drawings, wherein:

• Figure 1 shows a longitudinal schematic view of a plant for the thermal treatment of friction elements, in particular brake pads, according to the invention;
• Figure 2 shows a schematic plan view of the plant in figure 1;
• Figure 3 shows a large scale perspective view from above of three quarters of the key components of the plant in figures 1 and 2, arranged as per the usage configuration; and
• Figure 4 shows an enlarged scale transversal schematic view of the plant in figure 1;

Detailed description

[0014] With reference to figures 1 and 2, presented as a whole with 1 is a plant for the thermal treatment of braking elements 2, in particular brake pads (figure 3), which are known and illustrated for the sake of simplicity schematically only. More generally, the plant 1, though designed to treat braking elements, can perform a desired thermal treatment on friction elements of any type, for example clutch discs. In the following non limiting description, without the loss of any information in general, specific reference will be made to brake pads.

[0015] The plant 1 is preferably but not necessarily placed immediately downstream of a station 3, known and indicated schematically with a hatched block in figure 2, which is designed to carry out a known forming step upon the braking elements 2, comprising the pressing of a block of friction material onto a metal support.

[0016] The braking elements 2 leave the station 3 and the corresponding forming step and are transferred to the plant 1, by means of a known type of conveyor 4, for example consisting of a conveyor belt, upon which the braking elements 2 are laid out according to a known arrangement and technique.

[0017] The plant 1 comprises a convective tunnel oven 5 presenting an inlet opening 6 at its first end 7 and an outlet opening 8 at its second end 9, opposite the first.

[0018] The plant 1 also includes conveyor means 10, for example comprising of one or more "belt" type conveyors, implemented in the form of a single conveyor belt or as a plurality of conveyor belts arrayed head to head and/or side by side, which pass(es) through the convective tunnel oven 5; in the example illustrated there are two conveyors 10 that are positioned next to each other and that have a development length that is greater than that of the tunnel oven 5 in order to have their first and their second opposing ends 11 and 12 of the conveyors 10 arranged externally to the tunnel oven 5, from which they emerge by means of the inlet and outlet openings 6 and 8, respectively.

[0019] The conveyors 10 are preferably implemented in the form of a transportation belt(s) of the known so-called "endless" type, in which at least one flexible element (belt) 13, "endless" in so far as the opposite extremities of the belt are connected together to form a closed stretched loop, is supported and moved by rollers 14, at least some of which are motorized, supported by a structure 15.

[0020] According to a first characteristic of the invention, the plant 1 also includes a plurality of trays 16, two of which are explained in detail and illustrated at a large scale in Figure 3.

[0021] The trays 16 each have a resting plate 18 which is evenly perforated and designed such that the friction elements 2 can be laid directly onto the perforated resting plate 18 laid in a position next to one another only, but not overlapping, as is well illustrated in figure 3.

[0022] The trays 16 are further designed to be piled on top of each other (generally in a vertical direction) whilst being kept distanced from one another in a stacking direction by an amount that is greater than the thickness of the friction elements 2 in the same stacking direction;

[0023] In figure 3 two trays 16 are stacked one on top of the other, but, in general, the trays 16 are stackable in groups 19 of multiple trays 16, such as seven or eight.

[0024] In addition, the conveyors 10 are designed to be loaded, at their first end 11, with groups 19 of stacked trays 16 containing the friction elements 2 and to transport a plurality of groups 19 of stacked trays 16 arranged next to one another through the convective oven 5 up to the outlet opening 8, at a controlled speed, determined for example by motorized rollers 14 or by other means of propulsion, of a known type and not shown for simplicity, for example mechanical pushers.

[0025] According to one aspect of the invention, each tray 16 includes, corresponding to at least one pair of its opposite sides 20 (in the example shown in figure 3 the trays 16 are rectangular and the sides are 20 are longitudinal sides) a plurality of resting feet 21 each of which has a bottom end 22 and an upper end 23.

[0026] The resting feet 21 of each tray 16 are cantilevered and protrude towards, and from, the part of their bottom end 22 below the perforated resting plate 18 of the tray 16, and the upper end 23 of each resting foot 21 has a seat 24 which is designed to receive and support the bottom end 22 of a corresponding resting foot 21 of another tray 16. The bottom ends 22 of the resting feet 21 are conical and the seats 24 of the upper ends 23 are circular such that the resting feet 21 of two overlapping trays 16 determine a self centering action for the piled up trays 16.

[0027] According to an aspect of the invention, the trays 16 are made from a cut and pressed metal sheeting and the resting feet 21, which are also metallic, are hollow on the inside and welded along the sides 20. The trays 16 are therefore relatively light.

[0028] According to another aspect of the invention, the plant 1 comprises at least one first manipulation robot 25 and one second manipulation robot 26, each with at least three numerically controlled axes of movement, the first robot 25 being positioned in front of the first end 11 of the conveyors 10 and the second robot 26 in front of the second end 12 of the conveyors 10.

[0029] The robots 25 and 26 can be of any known type, in the illustrated non-limiting example they are of the anthropomorphic type, and are each provided with a head 27 (figure 1) which is designed to grip the trays 16 one at a time and to move groups of friction elements 2, by means of a single movement, to and from the trays 16, from and to the respective conveyors for the friction elements 2.

[0030] In the non-limiting example illustrated, the heads 27 are provided with suction cups and/or grippers and/or magnetic grippers, known and not illustrated for simplicity, and the plant 1 is served by two conveyors, the conveyor 4 is arranged laterally at the end 11 of the conveyor means 10 and a conveyor 40 is arranged laterally at the end 12 of the conveyor means 10.

[0031] The robot 25 picks up, by means of the head 27, for example using the suction cups, for example a group of three friction elements 2 from the conveyor 4, if required it rotates them, and deposits them on the perforated support plate 18 of a tray 16 deposited and resting on the conveyor means 10, such as to arrange the group of elements 2 perpendicularly to the sides 20. The robot 25 continues by picking up another group of three (in the non-limiting example illustrated) friction elements 2 and places them adjacent to but not overlapping, next to the preceding side, preferably in a staggered manner, as illustrated in figure 3, such as to increase the filling of the perforated support plate 18, up until the tray 16 is completely full; it is noteworthy that according to the invention the filling of the trays 16 with the elements 2 is never complete, in the sense that portions of the support plate 18, which are provided with perforations, must remain free, such that air can freely circulate around the friction elements 2.

[0032] The robot 25 subsequently picks up an empty tray 26, as will be seen, again by means of the head 27 and places it above, but vertically removed from, the tray 16 that has just been filled with friction elements 2, it then begins also to fill this tray 16 with friction elements 2 and so on until a group 19 of stacked trays 16 is formed. In the meantime the conveyors 10, moving slowly, transport the groups 19 of trays 16 that have just been completed into the oven 5, in the example illustrated in groups of two at a time, arranged side by side on the conveyor means 10, illustrated for simplicity as a single straight conveyor belt in figures 1 and 2. It is clear however that the conveyor means 10 can include for example two adjacent lines implemented by means of two identical conveyor belts 10, positioned next to each other, as illustrated in figure 4, or by means of, for example, three conveyor belts arrayed head to head, each one being independently motorized.

[0033] At the opposite end 12 the robot 26 picks up groups of three (in the illustrated example) friction elements 2 from the tray 16 at the top of each group 19 of trays 16 that exits the outlet opening 8, and places them, for example after rotation of the head 27, onto the conveyor 40, which carries the treated friction elements 2 on to subsequent processing and/or to packaging. When there are no more friction elements on the tray 16 at the top of each group 19 of trays 16, the robot 26 picks up the empty tray 16 and then passes to the next, and so on until the trays 16 of each group 19 of trays 16 are empty.

[0034] In the non-limiting example illustrated (Figure 1), below the oven 5 and externally to the same there are two conveyor belts 28 side-by-side, the upper surfaces of which move in the opposite direction to an upper surface of the conveyors 10, as shown by the arrows in figure 1.

[0035] The robot 26 places the empty trays 16 onto the conveyor belt 28 situated below each conveyor 10, stacked one on top of one another in groups 19. The groups 19 of empty trays 16 are transported by the conveyor belts 28 back towards the end 11, where they are picked up one at a time by the robot 25 and transported back on the conveyors 10, where they are filled with friction elements 2 and re-stacked, as previously described, to be re-fed into the oven 5. Of course, also in this case the two conveyors 28 can be replaced by a single double-width conveyor 28 and/or a series of conveyors 28 arranged in tandem, head to head along the longitudinal length of the oven 5.

[0036] According to another feature of the invention, the convective tunnel oven 5 comprises environment air sucking means 29 (figure 1) and burner means 30 (illustrated schematically with a block only, comprising for example of one or more burners fed with the air sucked from the means 29 and by a suitable fuel, designed to generate a flow F of burned gases (figures 1 and 4). The means 29 and 30 are arranged substantially half way along the tunnel oven 5; also present are suction means 31 of the combustion products, that is, of the flow of burned gases F, consisting of at least one pair of extractors arranged substantially at the respective opposite ends 7 and 9 of the tunnel oven 5.

[0037] The fumes are then discharged through a stack 32 (figure 2), possibly after having passed through cavities in order to pre-heat the air sucked in by the means 29.

[0038] According to a not secondary characteristic of the invention, in order to ensure the desired optimal adhesion of the thermal cycle implemented by the plant to that envisaged during the design phase for the individual braking elements 2, the flow F of hot gases produced by the sucking means 29 and by the burner 30 is divided into a plurality of flows F1-Fn and F2-Fm which are transversely directed in the direction of travel of the conveyor belts 10 and of the trays 16 and that are fed into the oven 5 at different heights, such that each flow F1-Fn or F2-Fm flows substantially flush, or just above, the resting plate 18 of each tray 16.

[0039] In particular, the flows F1-Fn and F1-Fm are fed into the oven 5 through opposing longitudinal side walls 50 of the oven 5, from the outside to the inside and at right angles to the conveyors 10, to then be sucked by the extractors 31 through a central chimney 51 (Figure 4) which extends along the full length of the oven 5. The transverse velocity of the flows F1-n and F2-m that pass over the trays 16 must be between 5 and 15 m/sec in order to obtain turbulence at each tray 16 and within the oven 5 that is designed for optimal heat exchange with the braking elements 2.

[0040] In the non-limiting example illustrated, the inlet and outlet openings 6 and 8 are provided with guillotine type sliding doors 33 that open into "compensation" chambers at the input and output 34, said chambers are in turn connected to the interior of the oven 5 by means of further passages that are closed by doors.

[0041] Based on what has been described, it is evident that by means of the plant 1, a method is implemented according to the invention, for the thermal treatment of friction elements 2, in particular consisting of braking elements such as brake pads, comprising a convective heating step in which the friction elements 2 are transported through a convective oven 5 that is heated in such a way as to obtain a desired temperature profile on the friction elements 2 and in which, according to the invention, the friction elements 2 are arranged laid, in an orderly manner, upon a plurality of trays 16 each having a perforated resting plate 18 upon which the friction elements 2 are laid in a position next to one another only, but not overlapped.

[0042] The trays 16 are successively piled up on top of each other whilst being kept distanced from one another in a stacking direction by an amount that is greater than the thickness of the friction elements 2 in the same stacking direction and the convective heating step is performed within a convective tunnel-type oven 5 having conveyor means 10 that passes through it, upon which conveyor means the trays 16 which are piled up and containing the friction elements 2 are placed, thus forming upon the conveyor means 10 a plurality of groups 19, arranged side by side, of piled up trays 16 such that by advancing the conveyors 10 in the direction of the arrow indicated with D1 in figure 1 the friction elements 2 are transported through the entire tunnel oven 5, from the end 7 to the end 9, entering the oven 5 by means of the inlet opening 6 and leaving by means of the outlet opening 8.

[0043] During the convective heating step the friction elements 2, which preferably comprise brake pads, are brought up to a temperature of between 140 and 300°C by circulating, in a controlled manner thus causing the controlled circulation of a flow F of burned gases, due to forced convection, within the tunnel oven 5, dividing said flow F into a plurality of overlapping opposite flows F1-n and F2-m directed transversely to the direction of travel D1 of the conveyors 10.

[0044] Said flows of burned gases F1-n and F2-m is produced by sucking environment air and producing combustion substantially half way along the length of the tunnel oven 5, using means 29 and 30, then sucking the combustion products by means of at least one pair of extractors 31 positioned substantially at respective opposite ends 7,9 of the tunnel oven 5.

[0045] According to that which has been described, the friction elements 2 are arranged on the trays 16 and then taken from the trays 16 by means of at least one pair of manipulation robots 25,26 (the robots 25,26 can also be four, two robots 25 and two robots 26 positioned on the opposite sides of the oven 5) having at least three numerically controlled axis of movement and the first robot(s) 25 arranged at a first end 7 of the tunnel oven 5 provided with the inlet opening 6 and the second robot(s) 26 arranged at a second end 9 of the tunnel oven 5, opposite to the first end 7 and provided with the outlet opening 8 from the tunnel oven.

[0046] In addition, the trays 16 being picked up empty by the first robot 25 at the first end 7, are deposited empty onto the conveyors 10, a first tray 16 directly laid on the upper surface of the conveyor means 10 and subsequently filled by the first robot 25 with a plurality of friction elements 2, and the subsequent trays 16 piled on top of the first tray 16 and filled with friction elements 2 by the first robot 25 one at a time to form a group 19 of piled up trays 16;

[0047] The thermally treated friction elements 2 are picked up from the trays 16 by the second robot 26 at the second end 9, and the empty trays 16 are removed from the conveyor means 10 one at a time by the robot 26 and arranged upon the conveyor belt(s) 28, positioned below the tunnel oven 5, by means of which second conveyor belt 28 the trays 16 are carried back to the first end 7 to be picked up one at a time by the first robot 25.

[0048] Thanks to the method and plant described the filling of the oven 5 is optimized and the output of the oven is greatly accelerated, that is the quantity of friction elements 2 treated per unit of time is increased, whilst at the same time reducing the footprint of the oven 5. Selecting a convective tunnel oven leads to a drastic reduction also in the vertical dimensions whilst increasing productivity at the same time.

[0049] Finally, it has been experimentally found that the temperature profiles obtained on the friction elements 2 based upon equal thermal cycles are significantly more constant and uniform in the case of the plant and method according to the invention wherein it is the case that the same friction elements 2 are treated in known ovens, where the friction elements are laid directly onto a conveyor belt or onto supports that follow their movement through the oven and where, above all, the convective flow of hot gases is directed in a direction that is parallel to the direction of travel of the friction elements through the oven.

[0050] Each scope of the invention has thus been achieved.

Claims

1. A method for the thermal treatment of friction elements (2), in particular braking elements, comprising a convective heating step wherein friction elements are transported through a convective oven that is heated characterized in that, in combination:

i)- the friction elements (2) are arranged laid, in an orderly manner, upon a plurality of trays (16) each having a perforated resting plate (18) upon which the friction elements (2) are laid in a position next to one another only, but not overlapped;

ii) - the trays (16) are piled up on top of each other whilst being kept distanced from one another in a stacking direction by an amount that is greater than the thickness of the friction elements (2) in the same stacking direction;

iii) - the convective heating step is performed within a convective tunnel oven (5) having conveyor means (10) passing through it, upon which conveyor means the trays (16) which are piled up and that contain the friction elements (2) are placed, thus forming a plurality of groups (19) upon the conveyor means, arranged side by side, of piled up trays (16) such that by advancing the conveyor means (10) the friction elements (2) are transported through the tunnel oven (5) along a direction (D1) of travel;

iv) - said trays (16) being made from a cut and pressed metal sheeting.

2. The method according to claim 1, characterized in that during the convective heating step the elements of friction (2) are brought up to a temperature of between 140 and 300° C by causing the controlled circulation of a flow (F) of burned gases, due to forced convection, within the tunnel oven (5); the flow (F) of burned gases being divided into a plurality of overlapping flows (F1-n) and (F2-m), said flows being opposite to one another and directed transversely to the direction of travel (D1).

3. The method according to claim 2, characterized in that the flow of burned gases (F) is produced by sucking environment air, then sucking the combustion products by means of at least one pair of extractors (31) positioned substantially at the respective opposite ends (7,9) of the tunnel oven.

4. The method according to one of the preceding claims, characterized in that the friction elements (2) are consisting of brake pads.

5. The method according to one of the preceding claims, characterized in that the friction elements (2) are arranged on the trays (16) and then taken from the trays by means of at least one pair of manipulation robots (25,26) having at least three numerically controlled axis of movement arranged as a first robot (25) at a first end (7) of the tunnel oven which has an inlet opening (6) into the oven and a second robot (26) at a second end (9) of the tunnel oven, opposite to the first which has an outlet opening (8) from the tunnel oven; the trays (16) being taken empty by the first robot (25) at the first end, being deposited empty onto the conveyor means (10), a first tray (16) directly laid on the conveyor means (10) and subsequently filled by the first robot (25) with a plurality of friction elements (2), and the subsequent trays (16) piled on top of the first tray and filled with friction elements by the first robot (25) one at a time to form a group (19) of piled up trays; the friction elements being taken from the trays (16) by the second robot (26) at the second end (9), and the empty trays (16) being removed from the conveyor means (10) one at a time by the second robot (26) and arranged upon a belt conveyor (28), positioned externally below the tunnel oven (5), by means of which belt conveyor they are carried back to the first end (7) to be taken one at a time by the first robot (25).

6. A plant (1) for the thermal treatment of friction elements (2), in particular of braking elements such as brake pads, comprising a tunnel convective oven (5) presenting an inlet opening (6) at its first end (7) and an outlet opening (8) at its second end (9), opposite to the first, and conveyor means (10) which passes through the tunnel convective oven (5), and that have an extension in length that is greater than that of the tunnel oven, in order to have their first (11) and their second (12) opposite ends arranged externally to the tunnel oven (5), from which they emerge by means of inlet and outlet openings (6,8), respectively; characterized in that it further comprises:

i) a plurality of trays (16) each having a perforated resting plate (18) designed such that the friction elements (2) can be laid directly onto the perforated resting plate in a position next to one another only, but not overlapped;

ii) the trays (16) being designed to be piled on top of each other whilst being kept distanced from one another in a stacking direction by an amount that is greater than the thickness of the friction elements (2) in the same stacking direction;

iii) the conveyor means (10) being designed to be loaded, at its first end (11), with groups (19) of piled up trays containing the friction elements (2) and to carry in a direction of travel (D1) a plurality of groups (19) of piled up trays arranged side by side through the convective tunnel oven (5) beyond the outlet opening (8), at a controlled speed;

iv) - said trays (16) being made from a cut and pressed metal sheeting.

7. The plant according to claim 6, characterized in that each tray (16) comprises, at least one pair of its opposite sides (20), a plurality of resting feet (21), each of which has a bottom end (22) and an upper end (23), the resting feet (21) jutting out towards their bottom end below the resting plate (18), and the upper end (23) of each resting foot being provided with a seat (24) which is designed to receive and support the bottom end (22) of a corresponding resting foot (21) of another tray (16).

8. The plant according to claim 7, characterized in that the bottom ends (22) of the resting feet (21) are conical and that the seats (24) of the upper ends are circular such that the resting feet (21) of two overlapping trays (16) determine a self centering action for the piled up trays (16).

9. The plant according to one of the claims 6 to 8, characterized in that it further comprises at least one first (25) and one second (26) manipulation robot, each having at least three numerically controlled axes of movement, the first robot (25) being positioned in front of the first end (11) of the conveyor means (10) and the second robot (26) in front of the second end (12) of the conveyor means (10); the first and second robot being provided with a head (27) which is designed to grasp the trays (16) one at a time and to move the friction elements (2), in groups of one at a time, by means of a single movement, on and off the trays (16), to and from their respective conveyors (4,40) for the friction elements.

10. A plant according to one of the claims 6 to 9, characterized in that the convective tunnel oven (5) comprises environment air sucking means (29) and burner means (30) which are designed to generate a plurality of overlapping flows of burned gases (F1-n;F2-m) and combustion products sucking means (31) consisting of at least a pair of extractors positioned substantially at the respective opposite ends (7,9) of the tunnel oven; the overlapping flows of burned gases (F1-n;F2-m) being opposite to one another and directed transversely to the direction of travel (D1).

Ansprüche

1. Verfahren zur thermischen Behandlung von Reibelementen (2), insbesondere Bremselementen, umfassend einen Konvektionserwärmungsschritt, bei dem Reibelemente durch einen Konvektionsofen transportiert werden, der erwärmt wird, dadurch gekennzeichnet, dass in Kombination:

i)- die Reibelemente (2) geordnet auf eine Vielzahl von Tabletts (16) gelegt angeordnet werden, die jeweils eine gelochte Auflageplatte (18) aufweisen, auf die die Reibelemente (2) in einer Position nebeneinander, aber nicht überlappend, gelegt werden;

ii)- die Tabletts (16) aufeinander gestapelt werden, während sie in einer Stapelrichtung um ein Maß voneinander beabstandet gehalten werden, das größer ist als die Dicke der Reibelemente (2) in derselben Stapelrichtung;

iii)- der Konvektionserwärmungsschritt durchgeführt wird in einem Konvektionstunnelofen (5) mit dadurch hindurch verlaufenden Fördermitteln (10), wobei die Tabletts (16) auf den Fördermitteln aufgestapelt sind und die Reibelemente (2) enthalten, wodurch auf den Fördermitteln eine Vielzahl von nebeneinander angeordneten Gruppen (19) von aufgestapelten Tabletts (16) gebildet wird, sodass durch Vorschieben der Fördermittel (10) die Reibelemente (2) entlang einer Bewegungsrichtung (D1) durch den Tunnelofen (5) transportiert werden;

iv)- die Tabletts (16) aus einem geschnittenen und gepressten Metallblech hergestellt sind.

2. Verfahren nach Anspruch 1, dadurch gekennzeichnet, dass während des Konvektionserwärmungsschritts die Reibelemente (2) auf eine Temperatur zwischen 140 und 300 °C gebracht werden, indem eine kontrollierte Zirkulation eines Flusses (F) verbrannter Gase durch erzwungene Konvektion innerhalb des Tunnelofens (5) bewirkt wird; wobei der Fluss (F) der verbrannten Gase in eine Vielzahl von überlappenden Flüssen (F1-n) und (F2-m) aufgeteilt wird, wobei die Flüsse einander entgegengesetzt sind und quer zur Bewegungsrichtung (D1) gerichtet sind.

3. Verfahren nach Anspruch 2, dadurch gekennzeichnet, dass der Fluss der verbrannten Gase (F) erzeugt wird, indem Umgebungsluft angesaugt wird und dann die Verbrennungsprodukte mittels mindestens eines Paars von Extraktoren (31) angesaugt werden, die im Wesentlichen an den jeweiligen gegenüberliegenden Enden (7, 9) des Tunnelofens angeordnet sind.

4. Verfahren nach einem der vorhergehenden Ansprüche, dadurch gekennzeichnet, dass die Reibelemente (2) aus Bremsbelägen bestehen.

5. Verfahren nach einem der vorhergehenden Ansprüche, dadurch gekennzeichnet, dass die Reibelemente (2) auf den Tabletts (16) angeordnet werden und dann mittels mindestens eines Paars von Manipulationsrobotern (25, 26) mit mindestens drei numerisch gesteuerten Bewegungsachsen von den Tabletts genommen werden, das als ein erster Roboter (25) an einem ersten Ende (7) des Tunnelofens, das eine Einlassöffnung (6) in den Ofen aufweist, und ein zweiter Roboter (26) an einem dem ersten gegenüberliegenden zweiten Ende (9) des Tunnelofens ausgebildet ist, welches eine Auslassöffnung (8) aus dem Tunnelofen aufweist; wobei die Tabletts (16) leer von dem ersten Roboter (25) an dem ersten Ende genommen werden, leer auf den Fördermitteln (10) abgelegt werden, ein erstes Tablett (16) unmittelbar auf die Fördermittel (10) gelegt wird und nachfolgend von dem ersten Roboter (25) mit einer Vielzahl von Reibelementen (2) gefüllt wird, und die nachfolgenden Tabletts (16) auf das erste Tablett gestapelt werden und von dem ersten Roboter (25) eines nach dem anderen mit Reibelementen gefüllt werden, um eine Gruppe (19) gestapelter Tabletts zu bilden; wobei die Reibelemente von dem zweiten Roboter (26) an dem zweiten Ende (9) von Tabletts (16) genommen werden und die leeren Tabletts (16) von dem zweiten Roboter (26) eines nach dem anderen von den Fördermitteln (10) entfernt werden und auf einem Förderband (28), das außen unter dem Tunnelofen (5) positioniert ist, angeordnet werden und mit diesem Förderband zu dem ersten Ende (7) zurückbefördert werden, um von dem ersten Roboter (25) eines nach dem anderen genommen zu werden.

6. Anlage (1) zur thermischen Behandlung von Reibelementen (2), insbesondere von Bremselementen, wie beispielsweise Bremsbelägen, umfassend einen Tunnelkonvektionsofen (5), der eine Einlassöffnung (6) an seinem ersten Ende (7) und eine Auslassöffnung (8) an seinem dem ersten gegenüberliegenden zweiten Ende (9) aufweist, und Fördermittel (10), die durch den Tunnelkonvektionsofen verlaufen und die eine Längenausdehnung aufweisen, die größer ist als die des Tunnelofens, damit ihr erstes (11) und ihr zweites (12) gegenüberliegendes Ende außerhalb des Tunnelofens (5) angeordnet sind, aus dem sie mittels einer Einlass- und einer Auslassöffnung (6, 8) austreten; dadurch gekennzeichnet, dass sie ferner Folgendes umfasst:

i) eine Vielzahl von Tabletts (16), die jeweils eine gelochte Auflageplatte (18) aufweisen, die so ausgestaltet ist, dass die Reibelemente (2) in einer nur nebeneinander liegenden, jedoch nicht überlappenden Position direkt auf die gelochte Auflageplatte gelegt werden können;

ii) wobei die Tabletts (16) dazu ausgestaltet sind, aufeinander gestapelt zu werden, während sie in einer Stapelrichtung um ein Maß voneinander beabstandet gehalten werden, das größer ist als die Dicke der Reibelemente (2) in derselben Stapelrichtung;

iii) wobei die Fördermittel (10) dazu ausgestaltet sind, an ihrem ersten Ende (11) mit Gruppen (19) von gestapelten Tabletts, die die Reibelemente (2) enthalten, beladen zu werden und eine Vielzahl von Gruppen (19) mit einer gesteuerten Geschwindigkeit nebeneinander durch den Konvektionstunnelofen (5) in einer Bewegungsrichtung (D1) über die Auslassöffnung (8) hinaus zu befördern;

iv) -wobei die Tabletts (16) aus einem geschnittenen und gepressten Metallblech hergestellt sind.

7. Anlage nach Anspruch 6, dadurch gekennzeichnet, dass jedes Tablett (16) an mindestens einem Paar seiner gegenüberliegenden Seiten (20) eine Vielzahl von Standfüßen (21) umfasst, die jeweils ein unteres Ende (22) und ein oberes Ende (23) aufweisen, wobei die Standfüße (21) an ihrem unteren Ende unterhalb der Auflageplatte (18) vorstehen und das obere Ende (23) jedes Standfußes mit einem Sitz (24) versehen ist, der dazu ausgestaltet ist, das untere Ende (22) eines entsprechenden Standfußes (21) eines anderen Tabletts (16) aufzunehmen und zu stützen.

8. Anlage nach Anspruch 7, dadurch gekennzeichnet, dass die unteren Enden (22) der Standfüße (21) konisch sind und die Sitze (24) der oberen Enden kreisförmig sind, sodass die Standfüße (21) zweier überlappender Tabletts (16) eine Selbstzentrierung für die gestapelten Tabletts (16) bestimmen.

9. Anlage nach einem der Ansprüche 6 bis 8, dadurch gekennzeichnet, dass sie weiterhin mindestens einen ersten (25) und einen zweiten (26) Manipulationsroboter aufweist, die jeweils mindestens drei numerisch gesteuerte Bewegungsachsen aufweisen, wobei der erste Roboter (25) vor dem ersten Ende (11) der Fördermittel (10) und der zweite Roboter (26) vor dem zweiten Ende (12) der Fördermittel (10) positioniert ist; wobei der erste und zweite Roboter mit einem Kopf (27) versehen sind, der dazu ausgestaltet ist, die Tabletts (16) eines nach dem anderen zu ergreifen und die Reibelemente (2) in Gruppen von jeweils eins durch eine einzige Bewegung auf die und von den Tabletts (16) zu und von ihren jeweiligen Förderern (4, 40) für die Reibelemente zu bewegen.

10. Anlage nach einem der Ansprüche 6 bis 9, dadurch gekennzeichnet, dass der Konvektionstunnelofen (5) Umgebungsluftsaugmittel (29) und Brennermittel (30), die dazu ausgestaltet sind, mehrere überlappende Flüsse von verbrannten Gasen (F1-n; F2-m) zu erzeugen, und Verbrennungsproduktsaugmittel (31), bestehend aus mindestens einem Paar Extraktoren, die im Wesentlichen an den jeweils gegenüberliegenden Enden (7, 9) des Tunnelofens angeordnet sind, umfasst; wobei die überlappenden Flüsse von verbrannten Gasen (F1-n; F2-m) einander entgegengesetzt sind und quer zur Bewegungsrichtung (D1) gerichtet sind.

Revendications

1. Procédé de traitement thermique d'éléments de friction (2), en particulier d'éléments de freinage, comprenant une étape de chauffage par convection dans lequel des éléments de friction sont transportés à travers un four à convection qui est chauffé, caractérisé en ce que, en combinaison :

i) -les éléments de friction (2) sont agencés posés, d'une manière ordonnée, sur une pluralité de plateaux (16) ayant chacun une plaque d'appui perforée (18) sur laquelle les éléments de friction (2) sont posés dans une position les uns à côté des autres uniquement, mais sans chevauchement ;

ii) -les plateaux (16) sont empilés les uns au-dessus des autres tout en étant maintenus éloignés les uns des autres dans une direction d'empilement d'une valeur qui est supérieure à l'épaisseur des éléments de friction (2) dans la même direction d'empilement ;

iii) -l'étape de chauffage par convection est effectuée au sein d'un four tunnel à convection (5) ayant un moyen de transport (10) passant à travers celui-ci, moyen de transport sur lequel les plateaux (16) qui sont empilés et qui contiennent les éléments de friction (2) sont placés, formant ainsi une pluralité de groupes (19) sur le moyen de transport, agencés côte à côte, de plateaux empilés (16) de telle sorte qu'en faisant avancer le moyen de transport (10), les éléments de friction (2) sont transportés à travers le four tunnel (5) le long d'une direction (D1) de déplacement ;

iv) -lesdits plateaux (16) étant fabriqués à partir d'une tôle métallique coupée et pressée.

2. Procédé selon la revendication 1, caractérisé en ce que, pendant l'étape de chauffage par convection, les éléments de friction (2) sont amenés à une température comprise entre 140 et 300 °C en amenant la circulation régulée d'un écoulement (F) de gaz brûlés, du fait d'une convection forcée, au sein du four tunnel (5) ; l'écoulement (F) de gaz brûlés étant divisé en une pluralité d'écoulements se chevauchant (F1-n) et (F2-m), lesdits écoulements étant opposés les uns aux autres et dirigés transversalement à la direction de déplacement (D1).

3. Procédé selon la revendication 2, caractérisé en ce que l'écoulement de gaz brûlés (F) est produit par aspiration d'air ambiant, puis aspiration des produits de combustion au moyen d'au moins une paire d'extracteurs (31) positionnés essentiellement au niveau des extrémités opposées respectives (7, 9) du four tunnel.

4. Procédé selon l'une des revendications précédentes, caractérisé en ce que les éléments de friction (2) sont constitués de patins de frein.

5. Procédé selon l'une des revendications précédentes, caractérisé en ce que les éléments de friction (2) sont agencés sur les plateaux (16) puis prélevés des plateaux au moyen d'au moins une paire de robots de manipulation (25, 26) ayant au moins trois axes de mouvement commandés numériquement, agencés en tant que premier robot (25) à une première extrémité (7) du four tunnel qui a une ouverture d'entrée (6) dans le four et en tant que deuxième robot (26) à une deuxième extrémité (9) du four tunnel, opposée à la première, qui a une ouverture de sortie (8) hors du four tunnel ; les plateaux (16) étant prélevés vides par le premier robot (25) au niveau de la première extrémité, étant déposés vides sur le moyen de transport (10), un premier plateau (16) posé directement sur le moyen de transport (10) et remplis ultérieurement par le premier robot (25) avec une pluralité d'éléments de friction (2), et les plateaux ultérieurs (16) empilés au-dessus du premier plateau et remplis d'éléments de friction par le premier robot (25) un à la fois pour former un groupe (19) de plateaux empilés ; les éléments de friction étant prélevés des plateaux (16) par le deuxième robot (26) au niveau de la deuxième extrémité (9), et les plateaux vides (16) étant enlevés du moyen de transport (10) un à la fois par le deuxième robot (26) et agencés sur un transporteur à courroie (28), positionné de façon externe en dessous du four tunnel (5), transporteur à courroie au moyen duquel ils sont ramenés à la première extrémité (7) pour être prélevés un à la fois par le premier robot (25).

6. Installation (1) pour le traitement thermique d'éléments de friction (2), en particulier d'éléments de freinage tels que des patins de frein, comprenant un four tunnel à convection (5) présentant une ouverture d'entrée (6) au niveau de sa première extrémité (7) et une ouverture de sortie (8) au niveau de sa deuxième extrémité (9), opposée à la première, et un moyen de transport (10) qui passe à travers le four tunnel à convection (5), et qui a une extension en longueur qui est supérieure à celle du four tunnel, afin d'avoir ses première (11) et deuxième (12) extrémités opposées agencées de façon externe au four tunnel (5), duquel il émerge au moyen des ouvertures d'entrée et de sortie (6, 8), respectivement ; caractérisé en ce qu'il comprend en outre :

i) une pluralité de plateaux (16) ayant chacun une plaque d'appui perforée (18) conçue de telle sorte que les éléments de friction (2) peuvent être posés directement sur la plaque d'appui perforée dans une position les uns à côté des autres uniquement, mais sans chevauchement ;

ii) les plateaux (16) étant conçus pour être empilés les uns au-dessus des autres tout en étant maintenus éloignés les uns des autres dans une direction d'empilement d'une valeur qui est supérieure à l'épaisseur des éléments de friction (2) dans la même direction d'empilement ;

iii) le moyen de transport (10) étant conçu pour être chargé, au niveau de sa première extrémité (11), avec des groupes (19) de plateaux empilés contenant les éléments de friction (2) et pour transporter dans une direction de déplacement (D1) une pluralité de groupes (19) de plateaux empilés agencés côte à côte à travers le four tunnel à convection (5) au-delà de l'ouverture de sortie (8), à une vitesse commandée ;

iv) -lesdits plateaux (16) étant fabriqués à partir d'une tôle métallique coupée et pressée.

7. Installation selon la revendication 6, caractérisée en ce que chaque plateau (16) comprend, au niveau d'au moins une paire de ses côtés opposés (20), une pluralité de pieds d'appui (21), dont chacun a une extrémité inférieure (22) et une extrémité supérieure (23), les pieds d'appui (21) faisant saillie vers l'extérieur en direction de leur extrémité inférieure en dessous de la plaque d'appui (18), et l'extrémité supérieure (23) de chaque pied d'appui étant pourvue d'un logement (24) qui est conçu pour recevoir et supporter l'extrémité inférieure (22) d'un pied d'appui correspondant (21) d'un autre plateau (16).

8. Installation selon la revendication 7, caractérisée en ce que les extrémités inférieures (22) des pieds d'appui (21) sont coniques et en ce que les logements (24) des extrémités supérieures sont circulaires de telle sorte que les pieds d'appui (21) de deux plateaux se chevauchant (16) déterminent une action de centrage automatique pour les plateaux empilés (16).

9. Installation selon l'une des revendications 6 à 8, caractérisée en ce qu'elle comprend en outre au moins un premier (25) et un deuxième (26) robot de manipulation, ayant chacun au moins trois axes de mouvement commandés numériquement, le premier robot (25) étant positionné devant la première extrémité (11) du moyen de transport (10) et le deuxième robot (26) devant la deuxième extrémité (12) du moyen de transport (10) ; les premier et deuxième robots étant pourvus d'une tête (27) qui est conçue pour saisir les plateaux (16) un à la fois et pour déplacer les éléments de friction (2), par groupes d'un à la fois, au moyen d'un mouvement unique, sur les plateaux et hors de ceux-ci (16), vers et depuis leurs transporteurs respectifs (4, 40) pour les éléments de friction.

10. Installation selon l'une des revendications 6 à 9, caractérisée en ce que le four tunnel à convection (5) comprend un moyen d'aspiration d'air ambiant (29) et un moyen de brûleur (30) qui sont conçus pour générer une pluralité d'écoulements se chevauchant de gaz brûlés (F1-n ;F2-m) et un moyen d'aspiration de produits de combustion (31) constitué d'au moins une paire d'extracteurs positionnés essentiellement au niveau des extrémités opposées respectives (7, 9) du four tunnel ; les écoulements se chevauchant de gaz brûlés (F1-n ;F2-m) étant opposés les uns aux autres et dirigés transversalement à la direction de déplacement (D1).

Drawing