Abstract:
A brake actuation system of a hydraulic brake system, for actuating at least one front axle brake circuit having at least one front wheel brake, and for actuating at least one rear axle brake circuit having at least one rear wheel brake, the brake actuation system including at least one hand brake module which, when actuated, can activate both brake circuits. In order to provide an improved brake actuation system with a plurality of actuation capabilities, which system can also be utilized in light motorcycles and scooters without the restrictions of existing brake actuation systems, while simultaneously offering a simple concept and a reduced cost and weight, the hand brake module is hydraulically coupled into a combined hand brake module, the combined hand brake module being designed to simultaneously generate brake pressure in both brake circuits.

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
     This application is the U.S. National Phase Application of PCT International Application No. PCT/EP2014/061463, filed Jun. 3, 2014, which claims priority to German Patent Application No. 10 2013 210 275.5, filed Jun. 3, 2013 and German Patent Application No. 10 2013 213 324.3, filed Jul. 8, 2013, the contents of such applications being incorporated by reference herein. 
     FIELD OF THE INVENTION 
     The invention concerns a brake actuation system, in particular for a brake system of a motorized cycle. 
     BACKGROUND OF THE INVENTION 
     To increase traffic safety, motorized cycles such as motorcycles, scooters, quad bikes, trikes, light motorcycles and comparable vehicles, are increasingly being equipped with combination brakes and in some cases anti-lock braking systems which, in any actuation variant, can act on the front wheels and on the rear wheels simultaneously and comprise a plurality of brake circuits. 
     Brake actuation systems with multiple actuation possibilities are known, which comprise a hydraulic connection of the foot brake to the handbrake or vice versa. 
     It is not however possible, sensible or desirable to implement such brake systems in many areas of application, such as for example lightweight motorcycles, for construction reasons. Also the weight, space required, complexity and cost-intensity of the known brake actuation systems are worthy of improvement. 
     SUMMARY OF THE INVENTION 
     An aspect of the invention is an improved brake actuation system with multiple actuation possibilities, which can be used also on light motorcycles and scooters without the restrictions of the known brake actuation systems, and which at the same time offers simple packaging and a cost- and weight-saving. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Details, features, advantages and possible uses of the invention arise from the description below, with reference to the drawings. These show: 
         FIG. 1  an embodiment of a brake actuation system according to the invention. 
         FIG. 2  a simplified sketch of an embodiment according to the invention with a tandem hand actuation facility (for example for a two-wheeled vehicle). 
         FIG. 3  a sketch of a further embodiment according to the invention with a tandem hand actuation facility for a two-wheeled vehicle as in  FIG. 2 , but with an interposed hydraulic-electronic control unit, for example an ABS unit. 
         FIG. 4  a sketch of a further embodiment according to the invention with a tandem hand actuation facility for a three-wheeled vehicle, with an interposed hydraulic-electronic control unit, for example an ABS unit. 
         FIG. 5  a sketch of a further embodiment according to the invention with a tandem hand actuation facility for a four-wheeled vehicle (for example a quad bike) with an interposed hydraulic-electronic control unit, for example an ABS unit. 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     
       FIG. 1 
     
     An embodiment of the brake actuation system  1  according to the invention has a combination handbrake module  5 , which comprises an approximately cylindrical housing  19  with a piston bore  8  therein filled with a pressure medium and having a floor  9 . An actuating piston  6 , which can be actuated manually by a hand lever  18 , is arranged in the piston bore  8  so as to be guided displaceably in an actuation direction B. A sealing collar  29 , which allows a fluid flow in the direction of the floor  9 , is mounted on the actuating piston  6 , whereby pressure can be built up on movement of the actuating piston  6  in the piston bore  8  in the actuation direction B. A centrally perforated cover  20  serves to close the housing  19 . 
     A floating piston  7  is positioned in the piston bore  8  between the actuating piston  6  and the floor  9 . The floating piston  7  is arranged displaceably in the actuation direction B and is elastically tensioned between the floor  9  and the actuating piston  6 ; it has a plurality of direction-dependent sealing collars  12 ,  13 ,  21  and divides the piston bore  8  into two pressure chambers  10  and  11 , wherein the first pressure chamber  10  is delimited between the floor  9  and the floating piston  7  and is hydraulically connected via a port to a front axle brake circuit  2 , and the second pressure chamber  11  is delimited between the floating piston  7  and the pressure piston  6  and is hydraulically connected via another port to a rear axle brake circuit  3 . If required, the allocation of the pressure chambers to the brake circuits may also be reversed within the invention. 
     Two elastic elements  28  and  28 ′ formed as coil springs are arranged pretensioned between the floor  9  and the floating piston  7 , and between the floating piston  7  and the actuating piston  6  respectively, and serve in particular to return the moved piston to its respective unactuated starting position. In addition, the floating piston  7  is pressed by the elastic element  28 ′ against a stop  16  protruding into the piston bore  8 , which is formed in the embodiment shown as a clamping ring engaging in a groove. Evidently, further embodiments for performing the same function are permitted within the invention for both the elastic elements  28 ,  28 ′ and for the stop  16 . 
     The sealing collars  12  and  13  are arranged on the floating piston  7  spaced apart from each other and oriented in the same direction, allowing flow in the direction of the pressure chamber  10  and sealing in the opposite direction, whereas the sealing collar  21  is arranged allowing flow in the direction of pressure chamber  11 , on the end of the floating piston  7  facing the pressure chamber  11 . 
     In a region of the piston bore  8  lying between the sealing collars  12  and  13 , a hydraulic port  22  is provided for connection of a simple conventional handbrake module  4 , wherein a pressure chamber  24  of the handbrake module  4  is connected via a hydraulic line  23  to said port  22 . The conventional handbrake module  4  is fitted with a single piston  25  which is also actuated manually by means of a hand lever, acts on the pressure chamber  24  and is elastically pretensioned to return by an elastic spring element  28 ″. 
     Furthermore, both the combination handbrake module  5  and the simple handbrake module  4  each have an integrated pressure medium reservoir  26 ,  26 ′ for supplying the pressure chambers  10 ,  11 ,  24  with pressure medium. Evidently, within the invention, embodiments are possible with merely one pressure medium reservoir which is connected to at least one of the handbrake modules  4 ,  5  via at least one hydraulic connecting line, not shown in the figure. 
     When this simple handbrake module  4  is actuated, the pressure medium flows out of the pressure chamber  24  through the line  23  and port  22 , into the intermediate space delimited by the similarly oriented sealing collars  12  and  13  around the floating piston  7  in the combination handbrake module  5 . This pressure medium flows over the sealing collar  12  lying closest to the floor  9  and at the same time moves the floating piston  7  in the direction of the actuating piston  6  via the sealing collar  13  which seals in this direction. In this way, the same pressure is set in both pressure chambers  10  and  11 , and in the brake circuits  2  and  3  connected thereto, as in the pressure chamber  24 . 
     If the combination handbrake module  5  is actuated in addition or exclusively, the actuating piston  6  moves in the direction of the floor  9 . At its end facing the actuating piston  6 , the floating piston  7  has the sealing collar  21  which seals in the direction of the floor  9 . Thus, on movement of the actuating piston  6 , the floating piston  7  is also moved by half the travel distance of the actuating piston  6 , so that the pressure is built up simultaneously in pressure chambers  10 ,  11 ,  24  and in the brake circuits  2 ,  3 . On failure of the front axle brake circuit  2 , the floating piston  7  goes to stop on the floor  9 , whereby pressure can continue to be built up in the pressure chambers  11  and the rear axle brake circuit  3 , but with an extended travel of the actuating piston  6 . On failure of the rear axle brake circuit  3 , the actuating piston  6  goes to stop on the floating piston  7 , so that pressure can continue to be built up in the pressure chamber  10  and the front axle brake circuit  2 . 
     Even on failure of all three sealing collars  12 ,  13  and  21 , an even pressure build-up and pressure distribution in the two brake circuits  2 ,  3  is still possible through the handbrake module  4  alone. 
     The embodiment of the combination handbrake module  5  shown has a hydraulic connection for two brake circuits  2 ,  3 , which are hydraulically connected to the pressure chambers  10  and  11  respectively. A design with a single connected brake circuit would however also be possible within the invention, for example by omitting the floating piston  7  and one of the brake circuits. 
     
       FIG. 2 
     
     The brake actuation system  1  described above is incorporated in a hydraulic brake system  100 . In the embodiment according to the invention shown, the brake system  100  has a front wheel brake  14  connected to the front axle brake circuit  2 , and a rear wheel brake  15  connected to the rear axle brake circuit  3 , so that the two wheel brakes  14  are directly connected hydraulically to the respective pressure chambers  10  and  11  in the combination handbrake module  5 . 
     The brake actuation system  1  according to the invention can thus be used particularly easily for two-wheeled motor vehicles (motorbikes, scooters etc.) but also for unmotorized vehicles such as bicycles without ABS. For this, the combination handbrake module  5  and the simple handbrake module  4  are connected together by the hydraulic line  23  and attached to a handlebar  27  of the vehicle in an ergonomically favorable fashion. 
     The reduction in components compared with the known brake actuation systems means that fewer costs are incurred for the components themselves, the fixing to the vehicle, and for the hydraulic connecting elements. As well as the advantages cited above, this also leads to simple packaging and a weight saving. 
     
       FIG. 3 
     
     In contrast to the embodiment in  FIG. 2 , the further embodiment according to the invention shown here has a hydraulic-electronic control unit  17  interposed between the pressure chambers  10 ,  11  in the handbrake module  5  and the respective wheel brakes  14  and  15  in the two brake circuits  2  and  3 , so that the wheel brakes  14  and  15  are not necessarily evenly controlled exclusively manually by the handbrake module  4  and/or combination handbrake module  5 , but may also be set regulated electronically by the control unit  17 . In this way, for example, an ABS control system can be implemented particularly easily on a two-wheeled vehicle. 
     
       FIG. 4 
     
     In three-wheeled vehicles such as for example trikes, the brake system  100  according to the invention can be adapted particularly easily, even without any structural changes to the brake actuation system  1 , in that one of the brake circuits, for example the rear axle brake circuit  3 , is divided in the control unit  17  into two partial brake circuits  3   a  and  3   b  which accordingly trigger the two rear wheel brakes  15   a  and  15   b , as the embodiment shows. 
     
       FIG. 5 
     
     An embodiment of the brake system  100  according to the invention for four-wheeled vehicles, such as for example quad bikes, is also easy to implement in that, in contrast to the embodiment described above, both brake circuits  2  and  3  are divided in the hydraulic-electronic control unit  17  into part brake circuits  2   a ,  2   b  and  3   a ,  3   b  respectively, connected to the individual front wheel brakes  14   a ,  14   b  and rear wheel brakes  15   a ,  15   b  respectively. 
     REFERENCE NUMERALS 
     
         
         
           
               1  Brake actuation system 
               2  Front axle brake circuit 
               3  Rear axle brake circuit 
               4  Handbrake module 
               5  Combined handbrake module 
               6  Actuating piston 
               7  Floating piston 
               8  Piston bore 
               9  Floor 
               10  Pressure chamber 
               11  Pressure chamber 
               12  Sealing collar 
               13  Sealing collar 
               14  Front wheel brake 
               15  Rear wheel brake 
               16  Stop 
               17  Hydraulic-electronic control unit 
               18  Hand lever 
               19  Housing 
               20  Cover 
               21  Sealing collar 
               22  Port 
               23  Hydraulic line 
               24  Pressure chamber 
               25  Piston 
               26 ,  26 ′ Pressure medium reservoir 
               27  Handlebar 
               28 ,  28 ′,  28 ″ Elastic element 
               100  Brake system 
             B Actuation direction