Abstract:
The invention relates to a method for gluing a friction lining to a support by means of adhesive that develops its full adhesive effect under the effect of pressure and/or temperature. The invention is characterized in that the friction lining and the support are pressed together along with the adhesive before the adhesive develops its full adhesive effect in order to glue the friction lining to the support.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
       [0001]    This application is a Continuation of PCT/DE2011/001165 filed Jun. 3, 2011, which in turn claims the priority of DE 10 2010 024 939.4 filed Jun. 24, 2010, the priority of both applications is hereby claimed and both applications are incorporated by reference herein. 
     
    
     BACKGROUND OF THE INVENTION 
       [0002]    1. Field of the Invention 
         [0003]    The invention relates to a method for gluing a friction lining to a support by means of an adhesive that develops its full adhesive effect under the influence of pressure and/or temperature. The invention further relates to a tool for sticking a friction lining to a support by means of an adhesive. The invention further relates to a tool for stacked gluing of supports comprising friction linings that have been stuck to the supports. 
         [0004]    2. Description of Prior Art 
         [0005]    It is known from German patent specification DE 44 31 642 B4 to connect a friction lining to a support when producing a preform. The support can be connected to the finished lining during the course of a hot pressing procedure or by means of a separate gluing process. The object of the invention is to improve the gluing of friction linings to supports by means of an adhesive. 
         [0006]    With a method for gluing a friction lining to a support by means of an adhesive that develops its full adhesive effect under the influence of pressure and/or temperature, the object is achieved in that the friction lining and the support are pressed together along with the adhesive before the adhesive develops its full adhesive effect in order to stick the friction lining to the support. When affixing the friction lining to the support, the friction lining is pre-fixed to the support. The friction lining is then only ultimately fixed to the support when the glue develops its full adhesive effect. The glue develops its full adhesive effect in a subsequent crosslinking or curing process under the relatively prolonged influence of a higher temperature compared with during the affixation of the friction lining to the support. To affix the friction lining to the support, the adhesive is only subject over a short period to a high pressure and a lower temperature than when curing or crosslinking. The friction lining is preferably a clutch friction lining of a dry friction clutch, in particular a double clutch. The support is preferably a sheet metal support. The friction lining is preferably coated with adhesive. 
         [0007]    A preferred exemplary embodiment of the method is characterized in that the adhesive is made to flow under the influence of pressure and/or temperature, before the adhesive develops its full adhesive effect. The flowing adhesive distributes optimally between the support and friction lining. The flowing adhesive particularly advantageously penetrates, in part, the preferably porous friction lining. During this process, the pressure and/or the temperature is/are set such that the adhesive does not yet crosslink or cure. The adhesive only crosslinks or cures after the affixing process, at a much higher temperature over a longer period of time. 
         [0008]    A further preferred exemplary embodiment of the method is characterized in that the support and the friction lining are positioned and/or centered relative to one another before being pressed together. The support and friction lining are preferably positioned and/or centered in a special pressing tool. During the process, the support and friction lining are positioned relative to one another in particular in the circumferential direction. 
         [0009]    A further preferred exemplary embodiment of the method is characterized in that a plurality of friction linings stuck to supports are pressed together in a stacked-gluing process, wherein the adhesive develops its full adhesive effect. In the case of stacked gluing, the friction linings already stuck to the supports are pressed together at a high temperature over a longer period of time than during the previous affixing process, such that the adhesive crosslinks or cures. The pressure during crosslinking or curing is lower than when affixing the friction linings. 
         [0010]    With a tool for sticking a friction lining to a support by means of an adhesive, in particular by a method described above, the problem stated in the introduction is achieved in that the tool has a lower tool plate and an upper tool plate, between which the friction lining and the support are pressed together along with the adhesive. The terms “lower” and “upper” relate to the direction of action of the force of gravity. The friction lining is preferably coated with the adhesive. However, it is also possible to coat the support, or the support and the friction lining, with the adhesive. The two tool plates are preferably installed in a C-frame press, with which the required pressure for affixing the friction lining to the support can be applied. A heating plate is installed in the tool plate, which contacts the support, in order to introduce into the tool the heat required to affix the friction lining to the support. 
         [0011]    A preferred exemplary embodiment of the tool is characterized in that the lower tool plate has centering pins for the friction lining and centering pins for the support. The centering pins are used to position and/or center the friction lining and the support relative to the tool and relative to one another. 
         [0012]    A further preferred exemplary embodiment of the tool is characterized in that the centering pins taper conically at their free end. The centering and positioning of the friction lining and the support is thus facilitated, such that the process can be automated. 
         [0013]    A further preferred exemplary embodiment of the tool is characterized in that the centering pins are guided movably in the lower tool plate in their longitudinal direction and are biased by a spring in the direction of the upper tool plate. The positioning and centering of the support and friction lining is thus further facilitated. The tool according to the invention is preferably combined with further tools in a round plate facility. 
         [0014]    A further preferred exemplary embodiment of the tool is characterized in that the centering pins for the support have an outer diameter that is different from that of the centering pins for the friction lining. Corresponding through-holes for the centering pins are provided in the support and in the friction lining. The friction lining is preferably positioned and centered first on the lower tool plate. During this process, a through-hole in the friction lining for the centering pin of the support is left open. 
         [0015]    With a tool for stacked gluing of supports comprising friction linings that have been affixed to the supports in particular by a method described above, in particular using a tool described above, the above-stated object is achieved in that the tool for stacked gluing has centering rods, which are arranged radially to the outside of the friction linings stuck to the supports in order to position and/or center these friction linings between two press plates. A total of four centering rods are preferably guided into the corner regions of the preferably square press plates. Further positioning pins, which extend through the supports or friction linings, can be omitted. In the case of stacked gluing, the previously affixed friction linings are connected fixedly to the friction linings by applying pressure and high temperature over a relatively long period of time, wherein the adhesive cures or crosslinks. 
     
    
     
       DESCRIPTION OF THE DRAWINGS 
         [0016]    Further advantages, features and details of the invention will emerge from the following description, in which various exemplary embodiments are described in detail with reference to the drawing, in which: 
           [0017]      FIG. 1  shows a sectional view of a tool for sticking according to the invention, taken along a line I-I in  FIG. 2 ; 
           [0018]      FIG. 2  shows a plan view of the tool from  FIG. 1 ; 
           [0019]      FIG. 3  shows a perspective illustration of the section from  FIG. 1 ; 
           [0020]      FIG. 4  shows an enlarged detail IV from  FIG. 3 ; 
           [0021]      FIG. 5  shows an enlarged detail V from  FIG. 3 ; 
           [0022]      FIG. 6  shows a sectional view of a tool for stacked gluing; and 
           [0023]      FIG. 7  shows an enlarged detail VII from  FIG. 6 . 
       
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
       [0024]    A tool  1  for fastening, including an upper tool plate  2  and a lower tool plate  3  is illustrated in various views and details in  FIGS. 1 to 5 . In the sectional views of  FIGS. 1 and 3 , it can be seen that the upper tool plate  2  has a plurality of through-holes  5 ,  6 ,  7 ,  8 . The through-holes  5 ,  6  are used to receive the upper ends of centering pins  11 ,  12 , which are guided movably to and fro in the lower tool plate  3  in the longitudinal direction. The through-holes  7 ,  8  are used to fasten the upper tool plate  2  to a C-frame press (not illustrated). 
         [0025]    The lower tool plate  3  likewise comprises a plurality of through-holes  9 ,  10 . The through-holes  9 ,  10  are used to fasten the lower tool plate  3  to the C-frame press. The centering pins  11 ,  12  are guided movably to and fro in further through-holes. 
         [0026]    In the plan view illustrated in  FIG. 2 , it can be seen that the two tool plates  2 ,  3  each have a total of five through-holes for fastening the tool plates to the frame press. In addition, it can be seen that the tool  1  comprises a total of eight centering pins  11 ,  12 . The centering pins  11  are arranged alternately with the centering pins  12  in the circumferential direction. Each centering pin  11  is thus arranged between two centering pins  12  in the circumferential direction. Similarly, each centering pin  12  is arranged between two centering pins  11  in the circumferential direction. The centering pins  11  are assigned to a friction lining  15 . The centering pins  12  are assigned to a support  16 , which is designed as a sheet metal support. The friction lining  15  is coated with an adhesive, which is used to fasten the friction lining  15  to the support  16 . 
         [0027]    In  FIGS. 4 and 5 , it can be seen that the centering pins  11 ,  12  each have a conical tapering  21 ,  22  at their respective ends protruding from the tool plate  3 . At their ends arranged in the tool plate  3 , the centering pins  11 ,  12  each have a collar  35 ;  25 , which constitutes an axial stop for the movement of the centering pins  11 ,  12  upwardly from the tool plate  3 . 
         [0028]    The centering pins  11 ,  12  are each biased upwardly from the tool plate  3  by a spring  36 ;  26 , that is to say toward the upper tool plate  2 . The spring  36 ;  26  is arranged in each case with its upper end in the hollow centering pin  11 ,  12 . With its lower end, the spring  36 ;  26  is supported on a spring cap  37 ;  27 , which is fastened to the underside of the lower tool plate  3 . 
         [0029]    In  FIG. 4 , it can be seen that the centering pin  12  extends both through the friction lining  15  and through the support  16  arranged thereabove. The conical tapering  22  at the free end of the centering pin  12  protrudes in part beyond the support  16  and into the through-hole  5  in the upper tool plate  2  arranged thereabove. 
         [0030]    In  FIG. 5 , it can be seen that the centering pin  11  for the friction lining  15  protrudes upwardly beyond the friction lining  15 . The support  16  has a through-hole  39  in the region of the centering pin  11 . The centering pin  11  can extend through the through-hole  39  and into the through-hole  6  in the upper tool plate  3  arranged thereabove. 
         [0031]    The tool  1  for sticking illustrated in  FIGS. 1 to 5  is also referred to as an affixing tool. The two tool plates  2 ,  3  are fabricated for example from tool steel and are installed on the C-frame press via special guides. The friction lining  15  is centered and positioned on the lower tool plate  3  by the four centering pins  11 . The support  16  is then positioned and centered relative to the friction lining  15  via the four centering pins  12 . 
         [0032]    The press is then closed and pre-fixes the support  16  on the friction lining  15 . The pre-fixing process is also referred to as sticking or affixing. During the pre-fixing process, the support  16  is stuck to the friction lining  15 . The friction lining  15  is, of course, also stuck to the support  16  during this process. In a variant of the tool  1 , the friction lining  15  may be inserted first, followed by the support  16 . 
         [0033]    A heat-activatable, possibly solvent-containing, adhesive on the basis of nitrile rubber/phenol resin is preferably used as an adhesive. For the affixing process, a pressure of approximately 50 tons with an affixing time of approximately 10 seconds is preferably applied by the frame press. The affixing temperature is between 150 degrees Celsius and 205 degrees Celsius. At this affixing pressure and at this affixing temperature, the adhesive starts to flow, but does not yet cure. 
         [0034]    In each case, a friction lining  15  is stuck to a support  16 , or vice versa, in the tool  1 . After the affixing process, the stuck friction lining/support composite is removed from the opened tool  1 . The friction lining/support composite parts stuck together are then subjected to stacked gluing in a tool  41 . 
         [0035]    A tool  41  for stacked gluing is illustrated in  FIGS. 6 and 7  in various views. The stacked-gluing tool  41  comprises two press plates  42  and  43 . The press plate  42  may be arranged above the press plate  43  based on the direction of action of the force of gravity. A total of three stacks  45 ,  46 ,  47  comprising friction lining/support composite parts glued together are arranged between the two press plates  42  and  43 . Each stack comprises twelve stuck composite parts, which each comprise a friction lining  15 , which is affixed to the respective support  16 . An intermediate plate  51 ,  52  is arranged between the stacks  45 ,  46  and between the stacks  46 ,  47 . 
         [0036]    In the outer circumferential edge region of the tool  41 , four centering rods  54 ,  55  extend through the intermediate plates  51 ,  52  and to the outside of the stacks  45  to  47 . In accordance with a preferred exemplary embodiment, the four centering rods  54 ,  55  are arranged radially to the outside of the stacks  45  to  47  in the corner regions of the press plates  42 ,  43 , such that the friction linings  15  glued to the supports  16  are centered radially to the inside of the centering rods  54 ,  55 . 
         [0037]    A central threaded rod  60  extends through the press plates  42 ,  43 , the stacks  45  to  47  and the intermediate plates  51 ,  52 . A first nut  61  is fastened at one end of the threaded rod  60 . A second nut  62  is screwed onto the other end of the threaded rod  60 . A bearing  64 , which is designed as an axial deep groove ball bearing, and a disk spring assembly  65  are arranged between the nut  62  and the press plate  42 . 
         [0038]    A defined torque is introduced via the nut  62  and the central threaded rod  60  in order to tension the two press plates  42  and  43  against one another. In the case of stacked gluing, a sufficient pressure is applied to the tool  41 . During the process, the tool  41  is exposed to a temperature of approximately 205 degrees Celsius, for example in a furnace, for approximately six hours. In the case of stacked gluing, a much lower pressure of approximately three tons may possibly be sufficient with the component parts already stuck in order to cure or crosslink the adhesive. 
         [0039]    With stacked gluing, the adhesive crosslinks fully. Before the stacks  45  to  47  are removed, they are cooled to room temperature. The pressure during stacked gluing is preferably maintained from the moment at which the press plates  42 ,  43  are clamped, during the stacked gluing process in the furnace, until removal. Due to the combination according to the invention of the affixing process in the tool  1  illustrated in  FIGS. 1 to 5  with the stacked gluing in the tool  41  illustrated in  FIGS. 6 and 7 , extremely high requirements in terms of burst speed, in particular after thermal damage, can be met. 
       LIST OF REFERENCE SIGNS 
       [0000]    
       
           1  tool 
           2  upper tool plate 
           3  lower tool plate 
           5  through-hole 
           6  through-hole 
           7  through-hole 
           8  through-hole 
           9  through-hole 
           10  through-hole 
           11  centering pin 
           12  centering pin 
           15  friction lining 
           16  support 
           21  conical tapering 
           22  conical tapering 
           25  collar 
           26  spring 
           27  spring cap 
           35  collar 
           36  spring 
           37  spring cap 
           39  through-hole 
           41  tool 
           42  upper press plate 
           43  lower press plate 
           45  stack 
           46  stack 
           47  stack 
           51  intermediate plate 
           52  intermediate plate 
           54  centering rod 
           55  centering rod 
           60  threaded rod 
           61  nut 
           62  nut 
           64  bearing 
           65  disk spring assembly