Abstract:
A friction clutch device, in particular for a drive train of a motor vehicle which is driven by internal, combustion engine, having a rotational axis, a housing, at least one pressure plate which can be displaced in the direction of the rotational axis relative to the housing for an actuation, and a spring device for loading the at least one pressure plate, in which friction clutch device the spring device has a first element for generating a pressure force which acts on the at least one pressure plate, and a second element which is separate structurally from the first element for transmitting an actuating force, in order to improve the friction clutch structurally and/or functionally.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
       [0001]    The present application claims priority of DE 10 2011 084 658.1, filed Oct. 18, 2011, the priority of this application is hereby claimed and this application is incorporated herein by reference. 
       BACKGROUND OF THE INVENTION 
       [0002]    1. Field of the Invention 
         [0003]    The invention relates to a friction clutch device, in particular for a drive train of a motor vehicle which is driven internal combustion engine, having a rotational axis, a housing, at least one pressure plate which can be displaced in the direction of the rotational axis relative to the housing for an actuation, and a spring device for loading the at least one pressure plate. 
         [0004]    2. Description of the Related Art 
         [0005]    DE 10 2008 005 918 A1 has disclosed a friction clutch having a housing, a pressure plate and an energy store which can be stressed between the housing and the pressure plate and via, which the pressure plate can be loaded in the closing direction of the friction clutch. The energy store is formed by a disk spring. The disk spring is fastened to and supported on the housing via an abutment in the manner of a two-arm lever. The disk spring can be elastically stressed axially between the housing and the pressure plate, with the result that it loads said pressure plate in the direction of the friction linings of a clutch plate. In order to disengage the clutch, the disk spring has to be loaded in the region of the tips of the disk spring tongues. 
       SUMMARY OF THE INVENTION 
       [0006]    An object of the present invention is to provide a friction clutch that improves structurally and/or functionally over the prior art. 
         [0007]    The object is achieved by a friction clutch device, in particular for a drive train of a motor vehicle which is driven by internal combustion engine, having a rotational axis, a housing, qt least one pressure plate which can be displaced in the direction of the rotational axis relative to the housing for an actuation, and a spring device for loading the at least one pressure plate, in which friction clutch device the spring device has a first element for generating a pressure force which acts on the at least one pressure plate, and a second element which is separate structurally from the first element for transmitting an actuating force. 
         [0008]    The friction clutch device can have a single clutch. The friction clutch device can have a double clutch. The friction clutch device can have a dry clutch. The friction clutch device can have a single plate clutch. The friction clutch device can have a wet clutch. The friction clutch device can have a multiple plate clutch. The friction clutch device can be arranged in a drive train of a motor vehicle. The motor vehicle can be a commercial vehicle. The motor vehicle can be an agricultural utility vehicle, such as a tractor. The motor vehicle can have an internal combustion engine. The motor vehicle can have a transmission. The friction clutch device can be arranged between the internal combustion engine and the transmission. The friction clutch device can have an input part. The input part can be capable of being driven by the internal combustion engine. The friction clutch device can have at least one output part. The transmission can be capable of being driven with the aid of the at least one output part. The friction clutch device can make driving off and changing of a transmission gear ratio possible. 
         [0009]    Starting from a completely disengaged actuating position, in which substantially no power transmission takes place between the input Dart and the at least one output part, and moving as far as a completely engaged actuating position, in which substantially complete power transmission takes place between the input part and the at least one output part, the friction clutch device can make an increasing power transmission possible in a manner which is dependent on the actuation, it being possible for power transmission to take place frictionally between the input part and the at least one output part. Conversely, starting from a completely engaged actuating position, in which substantially complete power transmission takes place between the input part and the at least one output part, and moving as far as a completely disengaged actuating position, in which substantially no power transmission takes place between the input part and the at least one output part, a decreasing power transmission can be made possible in a manner which is dependent on the actuation. A completely engaged actuating position can be a closed actuating position. A completely disengaged actuating position can be an open actuating position. 
         [0010]    A double clutch can have a first output part and a second output part. With the aid of the double clutch, the input part on one side and the first output part and/or the second output part on the other side can be connected to one another or can be disconnected from one another. In addition, a power flow from the input part can be moved in a fading change from the first output part to the second output part and vice versa. 
         [0011]    The at least one pressure plate can be connected fixedly to the housing so as to rotate with it. The friction clutch device can have a back-pressure plate. The backpressure plate can be connected fixedly to the housing so as to rotate with it. The back-pressure plate can be connected to the housing in an axially fixed manner. The pressure plate can be displaceable relative to the back-pressure plate. The friction clutch device can have two pressure plates. One of the two pressure plates can be an intermediate pressing plate. The intermediate pressing plate can be connected fixedly to the housing so as to rotate with it. The intermediate pressing plate can be capable of being displaceable axially with respect to the housing. The pressure plate can be displaceable relative to the intermediate pressing plate. A single clutch can have a pressure plate and a back-pressure plate. A double clutch can have a first pressure plate, a second pressure plate which is an intermediate pressing plate, and a back-pressure plate. 
         [0012]    The friction clutch device can have at least one clutch plate. The input part of the friction clutch device can have the housing, the at least one pressure plate and the back-pressure plate. The at least one output part of the friction clutch device can have the at least one clutch plate. The at least one clutch plate can be capable of being clamped between the pressure plate and the back-pressure plate. The at least one clutch plate can be capable of being clamped between the first pressure plate and the second pressure plate which is an intermediate pressing plate. The at least one clutch plate can be capable of being clamped between the second pressure plate, which is an intermediate pressing plate, and the back-pressure plate. The at least one clutch plate can have friction linings. A lining suspension system can be arranged between the friction linings of the at least one clutch plate. 
         [0013]    The spring device can load the at least one pressure plate in a prestressed manner in the engagement direction. The friction clutch device can have an automatically closing clutch. The spring device can load the at least one pressure plate in a prestressed manner in the disengagement direction. The friction clutch device can have an automatically opening clutch. The friction clutch device can have a push type clutch. The friction clutch device can have a pull type clutch. 
         [0014]    An actuation of the friction clutch device can take place with the aid of an actuating device. The actuating device can act on the second element. The actuating device can have an actuating bearing, such as a disengagement bearing. The actuating bearing can act on a radially inner section of the second element. The actuating bearing can have an annular shape. 
         [0015]    An actuation on a large diameter is made possible by way of the friction clutch device according to the invention. A greater transmission ratio can be realized. A pressing force can be increased. A greater wear reserve can be provided. 
         [0016]    The first element can be a disk spring which acts between the housing and the at least one pressure plate. The disk spring can have no tongues or only very short tongues. A large amount of installation space is available for a force edge of the disk spring. The disk spring has an enlarged force edge. High pressing forces can therefore be generated. High stress peaks are avoided in the force edge. The disk spring has a long characteristic curve profile. The disk spring can be configured to be adapted largely independently of a transmission ratio of the friction clutch device. 
         [0017]    Rivets can be arranged on the housing and the rivets can serve to center the disk spring. Starting from the housing, the rivets can be directed inwardly toward the disk spring. Instead of the rivets, the housing can have pin-shaped projections. The projections can be connected, for example screwed or welded, to the housing in a nonpositive, positive and/or material-to-material manner. The rivets can bear against a radially inner edge section of the disk spring. The disk spring can be secured against rotation with the aid of the rivets. 
         [0018]    The friction clutch device can have an actuating device, and the second element can have at least one lever which acts between the actuating device and the at least one pressure plate. A transmission ratio of the friction clutch device in the case of an actuation is fixed with the aid of the at least one lever. The transmission ratio of the friction clutch device can be set largely independently of a pressing force. 
         [0019]    Radially on the inner side, the at least one pressure plate can have a groove, into which the at least one lever engages. The at least one lever can engage at least virtually without play into the groove of the at least one pressure plate. There is therefore a secure connection between the at least one lever and the at least one pressure plate, both in the engagement direction and in the disengagement direction. 
         [0020]    Rivets can be arranged on the housing, and the second element can be arranged on the rivets. The second element is held on the rivets and can pivot on the rivets in the case of an actuation. 
         [0021]    The first element can act on the at least one pressure plate on a first diameter and the second element can act on said at least one pressure plate on a second diameter, and the first diameter can be greater than the second diameter. A large area and a favorable lever ratio are therefore available, in order to apply a high pressing force. 
         [0022]    A resilient pivoting bearing element can be arranged between the first element and the second element. The pivoting bearing element can be an undulating wire ring. A play in the direction of the rotational axis of the friction clutch device can therefore be minimized. Vibrations, in particular in an unactuated state, can be damped. 
         [0023]    Rivets with rivet heads can be arranged on the housing, and a pivoting bearing element can be arranged between the first element and the housing and a pivoting bearing element can be arranged between the second element and the rivet heads The pivoting elements can be wire rings. 
         [0024]    In summary and described in other words, the result of the invention is therefore, inter alia, a sheet metal cover single clutch with a disk spring and disengagement lever or disengagement lever spring and/or a tractor double clutch on the basis of a sheet metal cover single clutch with a disk spring which is riveted onto the cover. 
         [0025]    The clutch can consist of a sheet metals cover single clutch. The disk spring can have no tongues or only very short tongues. The disk spring can be clamped between the cover and the pressure plate and can therefore generate a pressing force on a pressure plate. The disk spring can be centered on an outer edge of a force edge via the pressure plate and can be secured against rotation by the sheet metal cover, for example by rivet pins in the sheet metal cover. Securing against rotation can be omitted in the case of a disk spring without tongues. An actuation of the clutch can take place via disengagement lever/lever spring; the disengagement lever/the lever spring can bring about a transmission ratio of the clutch. The disengagement lever/lever spring can be positioned via rivets on the cover of the single clutch. The disengagement lever/lever spring can have a wire ring as pivot point. Said wire ring can be supported on the rivets. The disengagement lever/lever spring can engage without play into groove of the pressure plate and, in the case of an actuation of the clutch, the disengagement lever/the lever spring can ensure a requested lift as a result. A resilient element, for example an undulating wire ring, can be situated between the disengagement lever/lever spring and the disk spring, in the region of an inner force edge of the disk spring, which undulating wire ring prevents axial play and therefore vibrations of the disengagement lever/the lever spring in the unactuated state. 
         [0026]    In the following text, one exemplary embodiment of the invention will be described in greater detail with reference to figures. Further features and advantages result from this description. Concrete features of this exemplary embodiment can represent general features of the invention. Features of this exemplary embodiment which are associated with other features can also represent individual, features of the invention. 
         [0027]    The various features of novelty which characterize the invention are pointed out with particularity in the claims annexed to and forming a part of the disclosure. For a better understanding of the invention, its operating advantages, specific objects attained by its use, reference should be had to descriptive matter in which there are described preferred embodiments of the invention. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWING 
         [0028]    In the drawing: 
           [0029]      FIG. 1  shows a drive train of a motor vehicle having internal combustion engine, a clutch and a transmission, and 
           [0030]      FIG. 2  shows a detailed view of a clutch having a housing, a pressure plate, a disk spring and a lever spring. 
       
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
       [0031]      FIG. 1  shows a drive train  100  of a motor vehicle having an internal combustion engine a clutch  104  and a transmission  106 . The internal combustion engine  102  serves to drive the motor vehicle. The motor vehicle is an agricultural utility vehicle, such as a tractor. The internal combustion engine has a rotational speed sensor  108  for determining an internal combustion engine rotational speed. 
         [0032]    Starting from the internal combustion engine  102 , the clutch  104  is arranged so as to follow the internal combustion engine  102  in the drive power flow direction. The clutch  104  is a friction clutch. The clutch is a single clutch. The clutch  104  has an input part and an output part. The part of the clutch  104  is drive connected to the internal combustion engine  102 . The output part of the clutch  104  is drive connected to the transmission  106 . An actuating device  110  is provided for actuating the clutch  104 . A sensor  111  serves to determine an actuating state of the clutch  104 . 
         [0033]    The transmission  106  is arranged so as to follow the clutch  104  in the drive power flow direction. The transmission  106  has a plurality of shiftable transmission stages. An actuating device  112  is provided for shifting the transmission stages. A sensor  114  serves to determine a set transmission stage. An output shaft of the transmission  106  is drive connected to a cardan shaft  116 . Drive wheels  120 ,  122  of the motor vehicle can be driven with a differential  118  connected in between. A rotational speed sensor  124  is provided for detecting a drive wheel rotational speed. 
         [0034]    The control device  126  is provided with input signals  128 , for example from the rotational speed sensor  108 , the sensor  111 , the sensor  114  and/or the rotational speed sensor control device  126  generates signals output signals, for example for actuating the internal combustion engine  102 , the actuating device  110  of the clutch  104  and/or the actuating device  112  of the transmission  106 . 
         [0035]      FIG. 2  shows a detailed view of a clutch  200 , such as a clutch  104  according to  FIG. 1 , having a housing  202 , a pressure plate  204 , a disk spring  206  and a lever spring  208 . The clutch  200  has an input part. The input part of the clutch  200  has the housing  200 , the pressure plate  204  and a back-pressure plate (not shown here). The back-pressure plate is connected fixedly to the housing  202 . The pressure plate  204  is connected to the housing  202  such that it can be displaced axially and is fixed to said housing  202  as to rotate with it. The clutch.  200  has an output part. The output part of the clutch  200  has a clutch plate  210 . The clutch plate  210  has friction linings. A lining spring is arranged between the friction linings. The clutch plate  210  can be clamped between the pressure plate  204  and the back-pressure plate. An actuation of the clutch  200  takes place way of axial displacement of the pressure plate  204 . 
         [0036]    Rivets, such as  212 , are arranged on the housing  202 . The rivets  212  are arranged such that they are directed inwardly toward the pressure plate  204 . A plurality of rivets  212  are arranged such that they are distributed over the circumference of the clutch  200 . The rivets  212  are arranged such that they are distributed uniformly over the circumference of the clutch  200 . Openings for receiving the rivets  212  are provided in the housing  202 . The rivets  212  are held in the openings in each case by way of a rivet head, such as  214 . 
         [0037]    The disk spring  206  has a shape in the manner of a flat ring. The disk spring  206  has a radially inner edge section  216 . The disk spring  206  has a radially outer edge section  218 . The disk spring  206  bears with its radially inner edge section  216  against the rivets  212  and is centered with respect to the rotational axis of the clutch  200  with the aid of the rivets  212  wire ring  220  for the pivotable mounting of the disk spring  206  is arranged in the direction of the rotational axis of the clutch  200  between the disk spring  206 , in particular the radially inner edge section  216  of the disk spring  206 , and the housing  202 . 
         [0038]    The pressure plate  204  has a supporting section  222 . The supporting section  222  is configured as a support in the manner of a ring or a ring section which projects toward the disk spring  206  in the direction of the rotational axis of the clutch  200 . The disk spring  206  rests with its radially outer edge section  218  on the supporting section  222  of the pressure plate  204 . 
         [0039]    The lever spring  208  has levers, such as  224 , which are directed in the radial direction. The levers  224  are connected to one another with the aid of a force edge. The levers  224  in each case have a radially inner lever end.  226  and a radially outer lever end  228 . The levers  224  are fastened to the rivets  212 . The levers  224  have openings for fastening to the rivets  212 . The rivets  212  have rivet heads, such as  230 , for fastening the lever spring  208 . The rivets  212  are arranged in the openings of the lever  224 . A wire ring  232  for pivotably mounting the lever spring  208  is arranged in the direction of the rotational axis of the clutch  200  between the lever spring  208  and the rivet heads  230 . 
         [0040]    The pressure plate  204  has a receiving section  234 . The receiving section  234  is directed radially inwardly. The receiving section  234  has a groove-like shape. The receiving section  234  is configured so as to be continuous or interrupted in the circumferential direction. The receiving section  234  has bearing sections in the direction of the rotational axis of the clutch  200 . The levers  224  of the lever spring  208  are received with their radially out lever ends  228  in the receiving section  234  of the pressure plate  204 . The lever ends  228  bear against theearing sections of the receiving section  234 . The lever ends  228  are received without play. 
         [0041]    An undulating wire ring  236  for pivotable mounting is arranged between the lever spring  208  and the disk spring  206 . With the aid of the wire ring  236 , the lever spring  208  and the disk spring are supported on one another in an elastically prestressed manner. The wire rings  220 ,  234 ,  236  bear against the rivets  212  and are centered with respect to the rotational axis of the clutch  200  with the aid of the rivets  212 . 
         [0042]    A pressing force is applied to the pressure plate  204  substantially with the aid of the disk spring. The pressure plate  204  can be displaced with the aid of the disk spring  206  in order to actuate the clutch  200 . The clutch  200  is self-closing under the loading of the force of the disk spring  206 . On account of the force of the disk spring  206 , the clutch plate  210  is clamped between the pressure plate  204  and the back-pressure plate in the engaged state, and the input part and the output part of the clutch  200  are drive connected to one another. 
         [0043]    In order to disengage the clutch  200 , the radially inner lever ends  226  of the levers  224  of the lever spring  208  are loaded. The levers  224  pivot about the pivoting bearings which are formed by way of the wire rings  232 ,  236 . The pressure plate  204  raises up from the back-pressure plate counter to the force of the disk spring  206 , and a drive connection between the input part and the output part of the clutch  200  is disconnected. A first lever arm of the levers  224  is formed between an acting location of the actuating device, such as disengagement bearing, and the pivoting bearing. A second lever arm of the levers  224  is formed between the pivoting bearing and the bearing section of the receiving section  234  of the pressure plate  204 . 
         [0044]    While specific embodiments of the invention have been shown and described in detail to illustrate the inventive principles, it will be understood that the invention may be embodied otherwise without departing from such principle.