Patent Publication Number: US-2019195293-A1

Title: Friction plate

Description:
The invention relates to a friction plate having a ring-shaped plate body, which is closed in the circumferential direction, on which body at least one friction coating is disposed, if necessary, and wherein the plate body has multiple recesses. Furthermore, the invention relates to a plate package comprising multiple friction plates disposed one behind the other in the axial direction. 
     Friction plates for plate friction systems are known as such from the state of the art. These can be structured with or without a friction coating, depending on whether an outer or an inner plate is involved. The friction plates are situated on plate carriers and are brought into a frictional lock with one another, as necessary, by means of an activation apparatus. 
     Friction plates with damping are also already known from the state of the art. Primarily, however, in this regard vibration damping stands in the foreground of considerations. 
     It is the task of the present invention to make available a plate friction system having reduced noise development. 
     This task is accomplished, in the case of the friction plate mentioned initially, in that the recesses are configured in slot shape, at least in part, and have multiple partial regions, wherein at least two partial regions run in different directions relative to one another, and wherein furthermore, the recesses are configured at a distance from the radially inner face surface and the radially outer face surface and/or that in the embodiment variant of the plate body with a friction coating, the slot-shaped recesses are disposed in the friction coating and the plate body in this embodiment variant is free of recesses, if necessary. Furthermore, the task is accomplished with a plate package that has at least one friction plate according to the invention. 
     The “sound body” of the friction plate is “divided” into smaller, acoustically independent bodies by means of the slot-shaped recesses, and thereby the noise behavior of the friction plate changes to a lower level. The overall noise level thereby drops. Therefore the noise development is already influenced in this way, so that additional damping devices or damping elements are not necessary. Furthermore, body vibrations of the friction plate are partially reflected and scattered at the side walls of the slots, so that the vibrations hinder themselves by means of a phase shift in the friction plate. The noise damping plate can be produced in simple manner, so that it can be easily implemented even on a large technical scale. Furthermore, very simple adaptation to different purposes of use of the friction plate can take place by means of the placement and the configuration of the slot-shaped recesses. In other words, system damping is possible with the friction plate. 
     According to a preferred embodiment variant, it is provided that the recess are configured as perforations. In this way, noise damping can be further improved. For example, it is possible, in this way, that the region around the slot-shaped recesses, which can be structured in tongue shape, for example, on the basis of the configuration of the slot-shaped recesses, are put into vibration, wherein these vibrations can take place at a frequency that lead to noise reduction in the overall frequency range of the noise development of the friction plate. 
     According to another embodiment variant, it can also be provided that the slot-shaped recesses are interrupted by at least one further recess, not slot-shaped, in particular by a further perforation. These larger recesses influence the flow of coolant. In particular, the coolant can flow through them in the embodiment as further perforations. As a result, the coolant, for example a cooling oil, not only contributes to cooling of the friction plate, but rather can also be used, in addition, for noise damping. 
     In order to be able to adapt the friction plate better to the most varied applications, and to not reduce the above effects as a result, it can be provided, according to different embodiment variants of the friction plate, that a friction coating is disposed on the plate body, and that at least part of the recesses is configured underneath the friction coating in the radial direction, and/or that a friction coating is disposed on the plate body and that at least part of the recesses is configured underneath the friction coating in the axial direction, and/or that a friction coating is disposed on the plate body and that at least part of the recesses extends continuously through the friction coating and the plate body, in the axial direction. 
     It can furthermore be advantageous if at least part of the recesses is filled, at least in part, with a material that demonstrates lower rigidity than the plate body. In this way, the result can be achieved that the vibration behavior of the acoustically active bodies of the friction plate cannot develop fully due to the filling, but rather the vibrations influence or hinder one another. In this way, a further reduction of the noise development of the friction plate can be achieved. 
    
    
     
       For a better understanding of the invention, it will be explained in greater detail, using the following figures. 
       The figures show, each in a (greatly) simplified, schematic representation: 
         FIG. 1  a detail of a plate package according to the state of the art in a side view; 
         FIG. 2  a first embodiment variant of the friction plate in a slanted view; 
         FIG. 3  a second embodiment variant of the friction plate in a slanted view; 
         FIG. 4  a third embodiment variant of the friction plate in a slanted view; 
         FIG. 5  a fourth embodiment variant of the friction plate in a slanted view; 
         FIG. 6  a fifth embodiment variant of the friction plate in a slanted view; 
         FIG. 7  a sixth embodiment variant of the friction plate in a slanted view; 
         FIG. 8  a seventh embodiment variant of the friction plate in a slanted view; 
         FIG. 9  an eighth embodiment variant of the friction plate in a slanted view; 
         FIG. 10  a ninth embodiment variant of the friction plate in a slanted view. 
     
    
    
     As an introduction, it should be stated that in the different embodiments described, the same parts are provided with the same reference symbols or the same component designations, wherein the disclosures contained in the description as a whole can be applied analogously to the same parts having the same reference symbols or the same component designations. Also, position information selected in the description, such as at the top, at the bottom, on the side, etc., for example, relates to the figure being directly described and shown, and must be transferred to the new position in the event of a change in position. 
     In  FIG. 1 , a detail of a known plate package  1  is shown. The plate package  1  has multiple inner plates  2  and multiple outer plates  3 , which can also be referred to as friction plates. The inner plates  2  are disposed alternating with the outer plates  3  in an axial direction  4 . The inner plates  2  are adjustable relative to the outer plates  3  in the axial direction  4 , by way of a corresponding activation mechanism, so that a frictional lock is formed between the inner plates  2  and the outer plates  3 . 
     The inner plates  2  have an at least approximately ring-shaped plate body  5  having a first surface  6  and a second surface  7  that lies opposite the first in the axial direction  4 . At least one friction coating  8  is disposed on the first and/or the second surface  6 ,  7 , in each instance. The inner plates  2  are therefore so-called coated plates. 
     The friction coatings  8  can be configured in accordance with the state of the art. 
     It can also be provided that the inner plates  2  do not have any friction coatings  8 . 
     The outer plates  3  also have an at least approximately ring-shaped plate body  9 , which is, however, free of friction coatings. The outer plates  3  are therefore the so-called counter-plates, which can be brought into a frictional lock with the friction coatings  8  of the inner plates  2 . However, the possibility also exists that the friction coatings  8  are disposed on the outer plates  3 , in particular if no friction coatings  8  are disposed on the inner plates  2 . 
     Preferably, the inner plates  2  and the outer plates  3  consist of a steel or comprise it. However, they can also consist of a different suitable material, in particular a metallic material. For example, the inner plates  2  can consist of a resin-bonded composite material or of a sintered material, as is already known. The friction coatings  8  disposed on the inner plates can consist, for example, of a carbon material or of a resin-bonded, if necessary fiber-reinforced paper coating or a resin-bonded coating or of a sintered material. Such friction coatings are known from the state of the art, so that reference is made to this. It is also possible that the friction coatings  8  are disposed on a carrier (the aforementioned plate body  5 ). The carrier preferably consists of steel or of another suitable material. 
     This fundamental structure of a plate package  1  is known from the state of the art. For this reason, reference is made to this relevant state of the art for further details. 
     The plate package  1  is part of a plate friction system, for example of a (wet-running) plate clutch, a brake, a holding apparatus, a differential lock, etc. 
     In  FIG. 2 , a first embodiment variant of a friction plate  10  is shown, as it is used in the plate package  1  according to  FIG. 1 . Specifically, an inner plate  2  in accordance with the representation in  FIG. 1  is shown. However, the friction plate  10  can also be an outer plate  3  ( FIG. 1 ), wherein in this case, it does not have a friction coating  8 . 
     The friction plate  10  is particularly provided for so-called wet operation. 
     The friction plate  10  can have at least one driver element  12 , for example in the form of an inner gearing, on a radially inner face surface  11 . 
     It should be mentioned at this point that the outer plates  3  can also have at least one driver element on a radially outer face surface. 
     A torque-proof connection with a further component of the plate friction system, for example a shaft in the case of the inner plates  2  or the housing of the plate friction system in the case of the outer plates  3 , can be produced by way of the driver elements, as is already known. 
     It is also possible that the inner plates  2  or the outer plates  3  are configured as so-called free-flying plates, in other words do not have any such driver elements, as is already known. 
     The plate body  5  of the friction plate  10  is configured to be closed in a circumferential direction  11 . 
     At this point, it should be pointed out that in the following, only the plate body  5  is discussed. In the event that the friction plate is an outer plate  3  ( FIG. 1 ), the following explanations regarding the plate body  5  can also be applied to the plate body  9  of the outer plate, if this body is also configured according to the invention. 
     Preferably, the plate body  5  is configured in one piece. However, it is also possible that the plate body  5  is composed of multiple segments that are connected with one another. 
     Multiple recesses  14  are provided or configured in the plate body  5  of the friction plate  10 . The recesses  14  are structured as perforations, according to a preferred embodiment variant, in other words extend continuously through the plate body  5  in the axial direction  4  ( FIG. 1 ). 
     The recesses  14  are configured, at least in part, in slot shape, in other words as slots  15 . In the embodiment variant shown, the recesses are structured as slots  15  in their entirety. 
     In the embodiment variant of the friction plate  10  shown in  FIG. 2 , seven recesses  14  or perforations are provided. However, it should be pointed out that this number of recesses  14  should not be viewed as being restrictive. Instead, the number of recesses  14  can amount to between 4 and 40. The precise number is based on the respective geometry and the intended use of the friction plate  10 , in other words, for example, whether it is used in a brake or in a clutch, and can be easily determined with a few experiments by a person skilled in the art, based on the teaching of the present description. 
     In the embodiment variant of the friction plate  10  that is shown, the recesses  14  are disposed uniformly distributed distributed in the plate body  4 . However, the possibility also exists, although this is not preferred, that the recesses  13  are disposed non-uniformly distributed in the circumferential direction  13  of the friction plate  10 . A distance  16  between two recesses  14  that are adjacent in the circumferential direction  13  can therefore be the same for all the recesses  14  or it can be smaller or greater between at least two adjacent recesses  14  than between the remaining recesses  14 , which are adjacent, in each instance. 
     The slot-shaped recesses  14  have a clearly greater total length in comparison with a width  17  (viewed in the front view in the direction of the axial direction  4 ). In particular, the total length can generally, within the scope of the invention, by a value greater, selected from a range of 5 times to 50 times, in particular from a range of 10 times to 40 times the width  17 . 
     The width  17  of the slot-shaped recesses  14  can generally be selected, within the scope of the invention, from a range of 50% to 150%, in particular from a range of 50% to 100%, of a thickness  18  of the plate body  5  (in other words without friction coatings  8 ), viewed in the direction of the axial direction  4 . 
     As is evident from  FIG. 2 , the slot-shaped recesses  14  do not run in a straight line, but rather have a multiple reversal of direction during the course of their total length. In the concrete exemplary embodiment, the slot-shaped recesses have a triple reversal of direction. Preferably, in this regard, an imaginary sheath  19 —viewed in the direction of the axial direction  4 —generally encloses a surface area that amounts to between 1% and 30%, in particular between 5% and 20%, of the total surface area of the plate body  5  (viewed in the same direction), within the scope of the invention. In this regard, the sheath  19  is the figure that surrounds a slot-shaped recess  14  on its outer circumference, as indicated with a broken line in  FIG. 2 , by analogy to a sheathing circle. 
     The slot-shaped recesses  14  therefore preferably have multiple partial regions (in general within the scope of the invention), which run in different directions from one another. In the embodiment variant of the friction plate according to  FIG. 2 , the slot-shaped recesses  14  have four partial regions  20  to  23 , which are disposed in such a manner that the slot-shaped recesses are configured approximately in V shape, viewed in the direction of the axial direction  4  ( FIG. 1 ), wherein the end regions are configured to be extended and running radially inward, as is evident from  FIG. 2 . Transitions between the partial regions  20  to  23  are preferably structured to be rounded (in general within the scope of the invention). 
     Within the scope of the invention, the slot-shaped recesses  14  are generally disposed or configured at a distance not only from the radially inner face surface  11  but also from a radially outer face surface  24  of the plate body  5 . The smallest distance from the radially inner face surface  11  can amount to between 1% and 40%, in particular between 5% and 30% of the outside diameter of the friction plate  10 . The smallest distance from the radially outer face surface  24  can amount to between 1% and 40%, in particular between 5% and 30% of the outside diameter of the friction plate  10 . 
     Aside from the slot-shaped recesses  14 , the plate body  5  can also have additional perforations  25 , which served for oil guidance and thereby for cooling of the friction plate. The perforations  25  pass through the plate body  5  in the axial direction  4  ( FIG. 1 ). 
     Within the scope of the invention, one or more, for example similar inner plates  2  and/or one or more, for example all of the outer plates  3  ( FIG. 1 ) can be formed by the friction plate  10 , in general. 
     In  FIGS. 3 to 10 , different embodiment variants of the friction plate  10  are shown, which can be independent, if necessary, wherein the same reference symbols or component designations as in  FIGS. 1 and 2  are used for the same parts. In order to avoid unnecessary repetition, reference is therefore made to the above, detailed description of these parts, i.e. this is pointed out, and therefore these can be considered to apply to the following embodiment variants of the friction plate  10 . 
     With the representations in  FIGS. 3 to 5 , it is intended to make it clear that the slot-shaped recesses  14 , i.e. the slots  15  can have different progressions, so as to thereby be able to influence the reduction of noises in the region of the friction plate  10 . However, it should be pointed out once again that the embodiments of the slot-shaped recesses that are shown in concrete terms is not to be understood as being restrictive. 
     For example, the slot-shaped recesses  14 , viewed in the direction of the axial direction  4 , in each instance ( FIG. 1 ), can be configured, at least approximately, in the shape of a W ( FIG. 3 ) or at least approximately corresponding to the image of a helical spring (viewed in a side view) ( FIG. 4  and  FIG. 5 , in the case of the latter, the small hooks). 
     In general, it should be noted that the slot-shaped recesses  14  of a friction plate  10  can also have different shapes from one another. It is furthermore possible, in general, that the slot-shaped recesses  14  can be disposed on different radial heights in the friction plate  10 , although they are shown as lying on the same radial height, in each instance, in the representations of  FIGS. 2 to 10 . 
     The embodiment variants of the friction plate  10  according to  FIGS. 2 to 5  have in common that at least a part of the slot-shaped recesses  14 , in particular all of them, is disposed or configured underneath the friction coating  8  in the radial direction. The expression “at least a part” means a number of the total number of recesses  14 , so that therefore all partial regions  20  to  23  of a recess  14  are disposed or configured underneath the friction coating  8  in the radial direction. However, it is also possible that not all the partial regions  20  to  23  of a recess  14  are disposed or configured underneath the friction coating  8  in the radial direction, but rather one or more partial region(s)  20  to  23  of a recess is/are disposed or configured underneath the at least one friction coating  8  in the axial direction  4  ( FIG. 1 ). 
       FIGS. 6 to 8  show embodiment variants of the friction plate  10  in which at least a part of the slot-shaped recesses  14  is disposed or configured underneath the at least one friction coating  8  in the axial direction  4  ( FIG. 1 ). What was explained above applies with regard to “at least a part.” 
     In  FIGS. 6 to 8 , part of the friction coating  8  was left out, so as to make the slot-shaped recesses  14  visible. Of course, the friction plate  19  also has the friction coating  8  in these regions. 
     It can furthermore be seen from these  FIGS. 6 to 8  that the friction coating  8  can also be formed by multiple friction coating segments disposed next to one another and spaced apart from one another in the circumferential direction  13 . 
     In the case of these embodiment variants of the friction plate  10 , the slot-shaped recesses  14  (or at least a part of the slot-shaped recesses  14 , i.e. at least some slot-shaped recesses  14 ) are covered by the friction coating  8  on one side or by the friction coatings  8  on both sides, in particular covered in their entirety. In this regard, the adhesive with which the at least one friction coating  8  is connected with the plate body  5  or  9  in the case of  FIG. 8 , which shows an outer plate  3 , will fill the slot-shaped recesses  14  at least in part, particularly in their entirety. In this way, a flow of force passing over the slot-shaped recesses  14  is achieved, wherein the buildup of vibrations having the same phase is prevented, however, due to the different materials of plate body  5 ,  9  and adhesive. The vibrations hinder one another reciprocally, and thereby noise reduction in the operation of the friction plate  10  is achieved. 
     At least a part of the slot-shaped recesses  14 , in particular all of them, can is filled, within the scope of the invention, with with a material that has a lower rigidity than the plate body  5 ,  9 , at least in part, in particular in their entirety, in general. This material can be selected, for example, from a group comprising or consisting of polyurethane, elastomers, such as natural rubber, for example, (carboxylated) nitrile/butadiene rubber, isoprene rubber, silicone elastomers, etc. 
     In this connection, it should be pointed out that the slot-shaped recesses  14  of these embodiment variants of the friction plate  10  can also be filled, at least in part, by the friction coating  8  or the friction coatings  8 . For example, this can be achieved in that the friction coating  8  or the friction coatings  8  are pressed into the slot-shaped recesses  14 . In this way, a shape lock can be achieved between the plate body  4 ,  9  and the friction coating  8  or the friction coatings  8 , which can improve the composite strength between friction coating  8  and plate body  4 ,  9 . 
     As is evident from  FIGS. 7 and 8 , it can be provided, according to another embodiment variant of the friction plate  10 , the at least a part, in particular all of the slot-shaped recesses  14  can be interrupted by at least one further, non-slot-shaped recess  26 , in particular a further perforation. In this regard, these further recesses  16  can be configured or disposed in the course of the slot-shaped recesses  14 , in other words between two partial regions  20 ,  21 , or on at least one end, in particular both ends of the slot-shaped recesses  14 . In this regard, it can be provided that the slot-shaped recesses  14  are configured without a change in direction, in other words at least approximately in a straight line, as is evident from  FIG. 8 . 
     In the case of these embodiment variants of the friction plate, as well, the perforations  25  described above can be provided for coolant guidance in the plate body  5 ,  9 . 
     The further recesses  26  can also be used for coolant guidance. However, they can also contribute to changing the acoustic behavior of the friction plate  10 . 
     In general, the perforations  25  and/or the further recesses  26 , viewed in the axial direction  4  ( FIG. 1 ), can have different cross-sectional shapes. For example, they can be structured to be circular or elliptical or in the shape of a polygon (quadrilateral, pentagonal, hexagonal, heptagonal, octagonal, etc.), wherein mixtures of these are also possible within a friction plate  10 . 
       FIG. 7  shows a further embodiment variant of the friction plate  10 , in which perforations  27  are also configured in the friction coating  8  (or in the friction coatings  8 ). With regard to the shape of these perforations  27 , what was said regarding the recesses  26  applies. 
     The perforations  27  are disposed to be congruent with the recesses  26 , in particular perforations, in the axial direction ( FIG. 1 ), i.e. completely congruent with the recesses  26  in the axial direction  4 . In this way, a coolant flow through the friction plate  10  can be achieved in the axial direction  4 . 
       FIGS. 9 and 10  are shown embodiment variants of the friction plate  10 , in which the slot-shaped recesses  14  are disposed or configured in the friction coating  8  or the friction coatings  8 . The slot-shaped recesses  14  can be disposed in the friction coating  8  or the friction coatings  8  in whole or in part, wherein in the latter case, the remainder of the slot-shaped recesses is disposed or configured in the plate body  5 . It is also possible that only some of the slot-shaped recesses  14  are disposed or configured in the friction coating  8  or the friction coatings  8 , and the remainder of the slot-shaped recesses  14  are disposed or configured in the plate body  5 . 
     For the case that slot-shaped recesses  14  are disposed or configured both in the friction coating  8  or the friction coatings  8  and in the plate body  5 , it can be provided that these slot-shaped recesses  14  have the same geometry and/or size. It can furthermore be provided that the slot-shaped recesses  14  lie in the friction coating  8  or the friction coatings  8  above the slot-shaped recesses  14  of the plate body  5 , in the axial direction  4  ( FIG. 1 ), so that the slot-shaped recesses  14  form a continuous perforation in the axial direction  4 . This can apply to all the slot-shaped recesses  14  or only some, in other words a part of the slot-shaped recesses  14 . 
     In contrast to the above explanations regarding the slot-shaped recesses  14  in the plate body  5 , the slot-shaped recesses  14  can be configured in the friction coating  8  or the friction coatings  8 , beginning at the radially inner face surface and/or the radially outer face surface of the friction coating  8  or the friction coatings  8 . 
     In  FIG. 10 , an alternative form of the slot-shaped recesses  14  is shown, in which these are configured in such a manner that they enclose a tongue-shaped region of the friction coating  8 . 
     The embodiment variants of the friction plate  10  in which the slot-shaped recesses  14  are disposed or configured exclusively in the friction coating  8  or the friction coatings  8  are preferably used in the case of friction plates  10  having so-called scatter-sintered coatings. 
     The exemplary embodiments show possible embodiment variants, wherein it should be noted at this point that various combinations of the individual embodiment variants with one another are also possible. 
     For the sake of good order, it should be pointed out, in conclusion, that for a better understanding of the structure of the friction plate  10 , it and its components were not necessarily represented true to scale. 
     REFERENCE SYMBOL LISTING 
     
         
           1  plate package 
           2  inner plate 
           3  outer plate 
           4  axial direction 
           5  plate body 
           6  surface 
           7  surface 
           8  friction coating 
           9  plate body 
           10  friction plate 
           11  face surface 
           12  driver element 
           13  circumferential direction 
           14  recess 
           15  slot 
           16  distance 
           17  width 
           18  thickness 
           19  sheath 
           20  partial region 
           21  partial region 
           22  partial region 
           23  partial region 
           24  face surface 
           25  perforation 
           26  recess 
           27  perforation