Abstract:
The present invention relates to an actuation system for a parking brake of a motor vehicle, comprising a foot or a hand-actuated manual actuation means ( 10 ) for tightening of the parking brake, wherein the parking brake is purely mechanically tightened via the actuation means, a locking mechanism ( 20 ) for tightening and releasing of the parking brake, wherein the actuation means ( 10 ) and the locking mechanism ( 20 ) are arranged at different positions of the motor vehicle, respectively.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application claims priority of international application no. PCT/EP2007/003171 filed Apr. 10, 2007, which claims priority of German patent application DE 10 2006 016 497.0 filed Apr. 7, 2006. 
     FIELD OF THE INVENTION 
     The present invention relates to an actuation system for a parking brake of a motor vehicle, particularly to a manually actuated parking brake which acts on the rear wheels. 
     PRIOR ART 
     In motor vehicles, the parking brake usually acts on the rear wheels of the motor vehicle. To this end, brake cables are tightened, which are connected to the brakes of the rear wheels by means of a hand-actuated parking brake unit or a foot-actuated parking brake unit. 
     Mechanical parking brake systems have to be arranged within the interior of the motor vehicle, such that the driver may reach them conveniently and can generate the required braking force. Further, the parking brake systems have to maintain the required braking force permanently and have to transmit the braking force securely to the rear wheels. 
     Such mechanical systems therefore have to be mounted in an appropriate way to the car body of the motor vehicle and require a certain space due to the required mechanical components for the locking of the hand or foot lever. 
     Due to this construction of manual parking brake systems, interior designers of motor vehicles are heavily constrained regarding the arrangement of the hand or foot lever unit. 
     Further, electrical parking brakes are known, which provide arbitrary design possibilities for the designer. Such electrical parking brakes, however, are quite expensive and susceptible for mechanical and electrical failures. Therefore, it can happen that the parking brake tightens accidentally due to an electric problem, but without a request of the driver. Further, the parking brake is always tightened with the same force if necessary or not. As a result, the brake cables and the brakes of the vehicle are unnecessarily strained. 
     It is therefore the technical problem to provide an actuation system for a parking brake, which can flexibly be arranged within the interior of the motor vehicle, and thereby provides the highest possible freedom of design for the interior designer. 
     Further, an actuation system for a parking brake should be provided which can be comfortably operated by the driver, which is more cost-efficient compared to electrical parking brakes, and which provides a high reliability. 
     SUMMARY OF THE INVENTION 
     The above-mentioned problems are solved by an actuation system for a parking brake according to patent claim  1 . 
     Particularly, the above-mentioned problems are solved by an actuation system for a parking brake of a motor vehicle comprising a foot or a hand-actuated manual actuation means for tightening of the parking brake, wherein the parking brake is purely mechanically tightened via the actuation means, a locking mechanism for tightening and releasing of the parking brake, wherein the actuation means and the locking mechanism are arranged at different positions of the motor vehicle, respectively. 
     Due to the structural separation of manual actuation means and locking mechanism of the actuation system according to the invention, the interior designer has a high flexibility during the arrangement and design of the foot or hand-actuated actuation means. For example, such an actuation means can easily be integrated into the center console or the dashboard of a motor vehicle, since it can be constructed particularly small. Particularly, due to the structural separation, the actuation means can be easily designed mechanically, such that it can be arranged at almost any arbitrary position within the interior of the motor vehicle for the manual actuation by the driver. 
     Thereby, the locking mechanism of the actuation system, which comprises the required mechanical components for the locking of the brake, can be arranged at any arbitrary other position within the motor vehicle, where more space is available, for example at the rear area of the motor vehicle. 
     Further, the freedom of design is increased, since the actuation means can be designed lighter, since only during actuation of the parking brake a force is applied to the actuation means and the actual load of the parking brake in tightened condition is maintained by the locking mechanism. Therefore, the actuation means in general can be provided smaller and more unconventionally with respect to the materials used and the design. 
     Compared to electrical parking brakes the manually tightened parking brake described herein has the advantage that a tightening happens only if the driver for sure wants it. By means of the construction it is excluded that the parking brake accidentally tightens due to an electric problem. 
     Further, the driver can determine the force by which the parking brake is tightened. Thereby, over-stressing of the brake cables and the brakes of the vehicle is avoided. In total, thereby, the reliability is increased compared to electrical parking brakes. 
     Preferably, the locking mechanism is constructed such that it can be mounted at the area of the rear axle, below the middle tunnel, below the seats or within the engine compartment of the motor vehicle. Preferably, the locking mechanism is arranged where free space is available, preferably near the brakes to be actuated. Thereby, the brake cables, which run from the locking mechanism to the rear wheels, need to be very short, only. 
     In a preferred embodiment the actuation means is provided such that it can be arranged in the area of the center console or the dashboard of the motor vehicle for manual actuation by the driver. 
     In a preferred embodiment, the actuation means automatically returns into a rest position after the tightening of the parking brake. Thereby, always the same appearance at the interior of the motor vehicle is provided for a released as well as for a tightened parking brake. Particularly, the handbrake lever does not extend into the interior, such that new possibilities of design result. For example, the space between the front seats can be used more efficiently, and overall more space is provided. 
     In a further preferred embodiment, the actuation means for applying a braking force is connected with the locking mechanism via a first pulling cable. The transmission of forces from the actuation means to the locking mechanism preferably is done via a pulling cable, since it can be arranged within the motor vehicle almost arbitrarily. However, other possibilities are conceivable to connect the actuation means with the locking mechanism, for example via a linkage, etc. 
     In a further preferred embodiment, the locking mechanism comprises locking means to maintain the braking effect of the parking brake, wherein the locking means can mechanically be released by means of a second pulling cable from a remote position to release the brake effect. Thereby, the releasing of the parking brake can be done mechanically independent from the tightening of the parking brake. The actuation element for the releasing of the parking brake therefore can be also be arranged at any arbitrary suitable position within the motor vehicle, since it is connected to the locking mechanism via a second pulling cable. Therefore, huge possibilities of design result for the interior designer. 
     In a further preferred embodiment, the locking mechanism comprises of locking means to maintain the locking effect of the motor vehicle, wherein the locking means can be released from a remote position by means of an electric, pneumatic or hydraulic actuator, to release the brake effect. Instead of a mechanical actuation, also an electric, pneumatic or hydraulic actuation of the locking means can be done to release the brake effect. Thereby, again the interior designer has the freedom to choose the design of this actuation means. By means of such an actuator, the release of the parking brake can also be done automatically be means of the board electronics, if for example the driver inserts a gear and presses the accelerator pedal. Thereby, an automatic release of the parking brake is provided, like it is provided by electrical parking brakes, without having to accept the disadvantages described above. 
     In a further preferred embodiment, the locking mechanism comprises a follower disk for the actuation of brake cables, which is pivotably supported around a pivot axis, a pivot lever which is pivotably supported around the pivot axis, which is connected with the first pulling cable, wherein the pivot lever comprises a follower bolt, which rotates the follower disk during tightening of the brake, and wherein the pivot lever after the tightening returns to its rest position, independently from the follower disk. 
     By means of these elements of the locking mechanism, a simple and robust possibility is provided to tighten the brake cables, wherein the manual actuation means (hand lever or foot pedal) returns to its initial position after the tightening. Therefore, the optical appearance of the interior is the same for the tightened condition of the parking brake as for the released condition. 
     According to a further preferred embodiment, the follower bolt extends into a slot within the follower disk. My means of this embodiment, the pivot lever can freely pivot to a certain extent with respect to the follower disk. 
     In a further preferred embodiment, the pivot lever is connected with the first pulling cable via a deflection pulley. Therefore, according to the pulley principle a force increase of 2:1 results for the pivot lever with respect to the first pulling cable. Therefore, the pivot lever can be made particularly small and the locking mechanism in total only requires little space. Alternatively, the needed force decreases, which has to be applied by the driver via the actuation means for tightening of the parking brake. Therefore, the actuation means, its support and the first pulling cable can be designed particularly small and lightweight and can be easily integrated into the interior of the vehicle. 
     In a further preferred embodiment, the locking mechanism comprises a ratchet-pawl mechanism. A ratchet-pawl mechanism is a particularly simple and reliable possibility to lock the locking mechanism. 
     In another preferred embodiment, the locking mechanism comprises a torsion spring clutch, which comprises a rotatably supported cylinder and a torsion spring, which is wound around the cylinder. By means of torsion spring clutch, the locking mechanism can also be locked, wherein during the locking no disturbing noises appear. Additionally, the force, which is required to open the torsion spring, is independent from the braking force. The release force of a ratchet-pawl mechanism, however, is directly dependent from the brake force. 
     Therefore, a torsion spring clutch is suitable for an automatic release of the parking brake by means of an actuator. 
     In a further preferred embodiment, the follower disk comprises a toothed segment, which is in engagement with a pinion at the cylinder, wherein the pinion comprises a smaller diameter than the toothed segment. By the provision of such a gear drive, the pinion with the torsion spring clutch rotates faster than the follower disk with the toothed segment, during tightening or releasing of the locking mechanism. Therefore, for the locking of the locking mechanism, a smaller force has to be applied to the pinion, compared with the toothed segment. Due to this reason, also the torsion spring clutch, which engages the pinion and locks the pinion, can be provided smaller. 
     Further preferred embodiments of the invention result from the subclaims. 
    
    
     
       SHORT DESCRIPTION OF THE DRAWINGS 
       In the following preferred embodiments of the invention are described by means of the figures, in which shows: 
         FIG. 1 : a schematic three-dimensional view of a motor vehicle from the bottom to show the arrangement of a locking mechanism according to the invention; 
         FIG. 2 : a three-dimensional view of a dashboard of a motor vehicle with an actuation means; 
         FIG. 3 : an elongational view of a preferred embodiment of a locking mechanism according to the invention, wherein parts thereof are eliminated to show the inner components in released condition; 
         FIG. 4 : an elongational view of a preferred embodiment of a locking mechanism according to the invention, wherein parts thereof are eliminated to show the inner components in tightened condition; 
         FIG. 5 : an elongational view of a preferred embodiment of a locking mechanism according to the invention in assembled condition with an element for electrical releasing; and 
         FIG. 6 : an elongational view of a preferred embodiment of a locking mechanism according to the invention in assembled condition with an element for mechanical releasing. 
     
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     In the following, preferred embodiments of the present invention are described with respect to the figures. 
       FIG. 1  shows a schematic view of a motor vehicle  1  from the bottom. Usually, the rear wheels of a motor vehicle  1  are mechanically braked while tightening of the parking brake  2  via two brake cables  16 . The brake cables  16  are connected with a locking mechanism  20  for locking and releasing of the parking brake  2 . As shown in  FIG. 1 , the locking mechanism  20  is mounted in the area of the rear axle of the motor vehicle  1 . 
     The force for the actuation of the locking mechanism  20  is mechanically transmitted via a first pulling cable  12 , which is connected with a mechanical actuation means  10 . 
     The actuation means  10  can be a foot lever or a handbrake lever of a conventional kind, wherein, however, no devices for the locking and releasing must be comprised. The actuation means  10  can also be unconventionally designed, as shown in  FIG. 2  in the form of a handbrake lever  10 , which comprises a U-shape and which is integrated into the dashboard  4  of the motor vehicle  1 . 
     Due to the spacial and functional separation between actuation means  10  and locking mechanism  20 , the interior designer of a motor vehicle  1  need to accept less restrictions with respect to the design of the actuation means  10 , since with the actuation means  10 , only manually a force has to be applied, however, the actuation means  10  itself must not be locked. 
     As it is shown in  FIG. 2 , the actuation means  10  can for example be integrated flush into the surface of the dashboard  4 . 
     Since locking mechanism  20  and actuation means  10  are spacially and functionally separated from each other, it is also possible that the actuation means  10  automatically returns to its rest position, as it is shown for example in  FIG. 2 . Thereby, the actuation means  10  does also not extend from the center console  4  in tightened condition of the parking brake  2 . 
     In order to signalize the driver if the parking brake is tightened or realized at the actuation means  10 , for example at the shown lever  10 , an optical display can be provided, which signalizes the actual status of the parking brake  2 . For example, a signal lamp  6  can be integrated into the handle of the actuation means  10 , which is enlighted if the parking brake  2  is tightened. 
     Additionally or alternatively, the status of the parking brake  2  can for example also be shown via an alphanumeric display. Further, a release knob  8  can be arranged at the actuation means  10 , which releases the parking brake  2 . 
       FIG. 3  shows an elongational view of a preferred embodiment of a locking mechanism  20  according to the invention with electrical release. The locking mechanism  20  consists of a frame  22 , which is connected with the car body of the motor vehicle  1 . At the frame  22 , a follower disk  40  is pivotably mounted by means of a pivot axis  42 , wherein at the follower disk  40  an actuation rod  90  is pivotably supported. The actuation rod  90  is connected with an equalizer element  100 , at which brake cables  16  are mounted. 
     If the follower disk  40  is pivoted around the pivot axis  42 , as indicated by arrow  41 , the actuation rod  90  moves the equalizer element  100 , and the brake cables  16  are tightened or released. 
     The equalizer element  100  is formed in the shaped of a balance and distributes the braking force, which was introduced from the actuation rod  90  equally onto both brake cables  16  for the right and left rear tire. 
     The locking mechanism  20  is further provided with a pivot lever  50 , which rotates the follower disk  40  by means of a follower disk bolt  52  during tightening of the parking brake  2 . To this end, the follower bolt  52  extends into a slot  44  which is curved around the pivot axis  52  within the follower disk  40 . The pivot lever  50  can freely rotate around the pivot axis  52  with respect to the follower disk  40  and takes along the follower disk  40  if the follower bolt  52  abuts the end of the slot  44 , as it is shown in  FIG. 3 . 
     The pivot lever  50  comprises of a deflection pulley  54  at its top end over which the first pulling cable  12  runs. The first pulling cable  12  is mounted at one end at a receptacle  26  of the frame  22  and at its other end at the actuation means  10 . During tightening of the actuation means  10 , the pulling cable  12  is tightened, as indicated by arrow  13 , whereby the pivot lever  50  is pivoted around the pivot axis  42 , as shown in  FIG. 4 . Thereby, the follower disk  40  is taken along by the follower bolt  55  and is likewise pivoted and the parking brake  2  is tightened. 
     By the deflection of the pulling cable  12  around the deflection pinion  54 , a force transmission according to the pulley principle is provided. Therefore, the deflection pulley  54  does only move half as much as the distance the pulling cable  12  is pulled. Therefore, the force at the pivot lever  50  doubles and it can be provided shorter compared to the condition if the pulling cable  12  would be directly connected to the pivot lever  50 . 
     After the tightening, the pivot lever  50  can return in its initial position—as shown in dotted lines in  FIG. 4 . This movement is also indicated by arrow  56 . To this end, the pivot lever  50  is biased by means of a spring to its initial position  50 ′. 
     Correspondingly, also the actuation means  10  returns to its rest position, wherein the parking brake  2  remains tightened. 
     For the locking of the follower disk  40 , i.e. for maintaining the braking effect of the parking brake  2 , the locking mechanism  20  is provided with locking means  40 ,  50 ,  60 ,  70 . 
     The locking means may comprise a conventional ratchet-pawl mechanism, as it is known from the prior art of conventional handbrake levers. 
     In the shown embodiment, the locking mechanism  20  comprises a torsion spring clutch  60 ,  70  which comprises a rotatably supported cylinder  70  and a torsion spring  60 , which is wound around the cylinder  70 . The rotatably supported cylinder  70  is provided with a pinion  72 , which engages the toothed segment  46  of the follower disk  40 . 
     The cylinder  70  is rotatably mounted at the frame  22  and is selectively blocked by the torsion spring  60 . To this end, one end  62  of the torsion spring  60  is mounted at the frame  22 . The other end  64  of the torsion spring  60  is connected with a release lever  80 , which likewise is rotatably fixed at the frame  22 . If the release lever  80  is pivoted and thereby also the end  64  of the torsion spring  60  is moved, the diameter of the torsion spring  60  can be increased or decreased. 
     The torsion spring clutch  60 ,  70  acts for the cylinder  70  as a one-way clutch, i.e. it allows a movement of the cylinder  70  in tightening direction of the parking brake  2 , but blocks a movement in release direction. 
     For releasing of the parking brake  2 , the release lever  80  is pivoted to the right, as shown in  FIG. 4  by arrow  65 , wherein the diameter of the torsion spring  60  is increased and thereby the cylinder  70  is released, such that is can freely rotate. 
     Thereby, also the follower disk  40  can freely rotate and the parking brake  2  is released. If the release lever  80  is not moved, the torsion spring  60  blocks the cylinder  70  in release direction, such that the follower disk  40  cannot return into the position shown in  FIG. 3 , and the brake effect of the parking brake  2  is maintained. 
     Since the follower disk  40  with respect to the pivot axis  42  comprises a larger diameter in the area of the toothed segment  46  compared to the pinion  72  of the rotatably supported cylinder  70 , the cylinder  70  moves faster than the follower disk  40  during a movement of those parts. Therefore, the torsion spring  60  must only generate a small friction force to lock the cylinder  70 . Therefore, the torsion spring  60  must not be dimensioned very powerful to maintain the brake force. 
     Further, the force to open the torsion spring  60  is independent from the braking force, what allows an easy release of the parking brake  2 . 
     As indicated, it is necessary to release the follower disk  40  to release the parking brake  2 , which is done by pivoting of the release lever  80 . Such a pivoting of the release lever  80  can be done by means of an electric, pneumatic or hydraulic actuator  30 , like it is shown in  FIG. 5 . Preferably, therefore an electric actuator  30  is used, which pulls the release lever  80  in direction of arrow  65 . 
     As it is shown in  FIG. 6 , however, also a mechanical actuator, like for example a second pulling cable  14  can be used to move the release lever  80  in direction of the arrow  65 , to release the parking brake  2 . 
     An electric actuator  30 , however, has the advantage that a release knob for the actuation of the electric actuator  30  can be arbitrarily arranged within the vehicle, for example at the dashboard of the motor vehicle  1 . Further, the electric actuator  30  can also be controlled by the board electronics of the motor vehicle  1 , and for example release the parking brake  2  automatically if the driver inserted a gear and actuates the accelerator pedal. By means of the actuation system according to the invention, therefore automatic release operations of the parking brake  2  are possible, which for example facilitate the starting at a hill. 
     Further, the release operation of the parking brake  2  can be controlled such that a release of the parking brake  2  is only possible if particular conditions are met, for example that the motor is running and the driver actuates the vehicle brakes. 
     To signalize the board electronics that the parking brakes  2  is tightened, the locking mechanism  20  further comprises a switch  24 , as it is shown in  FIGS. 3 and 4 , which is actuated by a stop  48  at the follower disk  40 . 
     The locking mechanism  20  further comprises, as shown in  FIG. 5 , a cover plate  28 , which supports the inner components and which is connected with the frame  22 . 
     The components of the locking mechanism  20  are preferably made of steel, however, fiberglass-reinforced plastic material, particularly PA can also be used for single or for all components. The actuation means  10  is preferably made of a plastic material and consists preferably of a fiberglass-reinforced PA. 
     
       
         
               
             
               
               
             
           
               
                   
               
               
                 LIST OF REFERENCE  
               
               
                 SIGNS 
               
               
                   
               
             
             
               
                   
               
             
          
           
               
                 1 
                 motor vehicle 
               
               
                 2 
                 parking brake 
               
               
                 4 
                 dashboard 
               
               
                 6 
                 signal lamp 
               
               
                 8 
                 release knob 
               
               
                 10 
                 actuation means 
               
               
                 12 
                 first pulling cable 
               
               
                 13 
                 arrow 
               
               
                 14 
                 second pulling cable 
               
               
                 16 
                 brake cables 
               
               
                 20 
                 locking mechanism 
               
               
                 22 
                 frame 
               
               
                 24 
                 switch 
               
               
                 26 
                 receptacle 
               
               
                 28 
                 cover plate 
               
               
                 30 
                 actuator 
               
               
                 40 
                 follower disk 
               
               
                 41 
                 arrow 
               
               
                 42 
                 pivot axis 
               
               
                 44 
                 slot in follower disk 
               
               
                 46 
                 toothed segment 
               
               
                 48 
                 stop 
               
               
                 50 
                 pivot lever 
               
               
                 52 
                 follower bolt 
               
               
                 54 
                 deflection pulley 
               
               
                 56 
                 arrow 
               
               
                 60 
                 torsion spring 
               
               
                 62 
                 first end 
               
               
                 64 
                 second end 
               
               
                 65 
                 arrow 
               
               
                 70 
                 cylinder 
               
               
                 72 
                 pinion at the cylinder 
               
               
                 80 
                 release lever 
               
               
                 90 
                 actuation rod 
               
               
                 100 
                 equalizer element