Abstract:
A system for a drive for actuating a parking brake operably involves a brake caliper. The brake caliper has at least one brake piston with a brake piston axis, the piston being actuatable by means of an operably actuating lever with a rotational center. An electric motor is fixed to the brake caliper and mechanically coupled to the actuating lever with the output shaft that exits the electric motor.

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
       [0001]    This application claims priority from International Ser. No. PCT/EP2011/000099 filed 12 Jan. 2011, the entire contents of which are incorporated herein by reference, which in turn claims priority from German Ser. No.: DE 10 2010 004 602.7 filed 13 Jan. 2010. 
     
    
     FIGURE FOR PUBLICATION 
       [0002]    FIG. 3 
       BACKGROUND OF THE INVENTION 
       [0003]    1. Field of the Invention 
         [0004]    The present invention relates to a drive for actuating a parking brake. More particularly, the present invention relates to drive for actuating a parking brake operably involving a brake piston being actuatable by an actuating lever with a rotational center. 
         [0005]    2. Description of the Related Art 
         [0006]    A brake caliper customarily comprises at least one brake disk, at least one brake lining and at least one brake piston. The brake piston presses the brake lining axially and at a right angle against the brake disk. When the driver actuates a known parking brake integrated in the brake caliper a force is applied by a hand brake lever and a Bowden wire fastened to it on the purely mechanical brake caliper. A linear introduction of force is converted into a torque in order to rotate an actuation lever. Finally, the torque must be converted back into a linear introduction of force that presses the brake lining against a brake disk. 
         [0007]    In such brake calipers with actuation lever the actuation lever is rotatably fastened in an area of the distal end of the brake piston to a housing around its cup axis. The cup axis is aligned either vertically or transversely, in particular at a right angle, to the axis of the brake piston. A transfer of force takes place in the cup as a function of the cup axis. A vertical arrangement, for example, requires a transfer of force from the lever via an eccentric arranged, e.g., in the cup to the brake piston. The design of the transfer of force from the lever onto the brake piston will not be discussed in detail here. 
         [0008]    In addition, hydraulic vehicle breaks have become known in the meantime from DE 197 32 168 C2 (the entire contents of which are incorporated by reference) that realize the above-described function of a parking brake electromechanically. To this end an electromotor is arranged laterally adjacent to a vehicle brake housing. An output shaft of the electromotor runs here with lateral distance parallel to a central axis of a brake piston for the forwarding of force. The output shaft exits from the electromotor on the side facing away from the brake piston. A stepdown gearing acts between the electromotor and the brake piston. 
         [0009]    Considering the known vehicle brakes, there is still a problem of providing a brake caliper with an integrated parking brake that is actuated in a conventional manner with a Bowden wire without having to make a basic change to the brake caliper and without considerably more construction space being required. A solution of the problem should be able to be used to the extent possible in all variants of brake calipers. 
         [0010]    It is therefore proposed that at least one of the concerns noted is addressed by the proposed electromechanical worm-spindle drive for an actuating parking brake. 
       ASPECTS AND SUMMARY OF THE INVENTION 
       [0011]    The present invention proposes a system involving a drive for actuating a parking brake in a brake caliper. The brake caliper has at least one brake piston with a brake piston axis, the piston being actuatable by means of an operable actuating lever with a rotational center. An electric motor is operably fixed to the brake caliper and mechanically coupled to the actuating lever with the output shaft that exits the electric motor. 
         [0012]    In one aspect of the proposed invention there is a drive, for actuating a parking brake in a brake caliper, comprising: at least one brake caliper, further comprising: at least one brake piston operable along a brake piston axis positioned on an actuation side, the brake piston operably engaging an actuation lever having a respective center of rotation, an electromotor having an output shaft providing motive rotational force fixably secured with the brake caliper, and the output shaft being operably coupled to the actuation lever, whereby operating the actuation lever operates the brake piston. 
         [0013]    According to another aspect of the proposed invention there is further provided a drive, wherein: the electromotor is fixably secured on an outside of the brake caliper. 
         [0014]    According to another aspect of the proposed invention there is further provided a drive, further comprising: a motor axis along the output shaft, and the motor axis being aligned transversly to the brake piston axis. 
         [0015]    According to another aspect of the proposed invention there is further provided a drive, wherein: the motor axis is aligned at one of perpendicular to the brake piston axis and parallel with the brake piston axis. 
         [0016]    According to another aspect of the proposed invention there is further provided a drive, wherein: the electromotor further comprises: a worm element on the output shaft, and the worm element operably coupled to the brake piston during a use thereof. 
         [0017]    According to another aspect of the proposed invention there is further provided a drive, wherein: the exiting output shaft of electromotor is arranged facing the brake position. 
         [0018]    According to another aspect of the proposed invention there is further provided a drive, wherein: the center of rotation of the actuation lever lies on the motor axis. 
         [0019]    According to another aspect of the proposed invention there is further provided a drive, wherein: the output shaft and the drive worm rotate cooperatively during a use of the drive along a worm-spindle transmission, the worm-spindle transmission having a spindle, the spindle aligned along the a spindle axis and operably coupled to the actuation lever during the use, and the spindle axis arranged opposing the motor axis. 
         [0020]    According to another aspect of the proposed invention there is further provided a drive, further comprising: an oblong hole defined on a distal end of the actuation lever, the oblong hole extending along a direction toward an operable center of rotation of the actuation lever, and the spindle operably engaging the oblong hole in a pivotable manner, whereby during the use the actuation lever is pivotable about the center of rotation. 
         [0021]    According to another aspect of the proposed invention there is further provided a drive, further comprising: a toothed segment on a distal end of the actuation lever. 
         [0022]    According to another aspect of the proposed invention there is further provided a drive, wherein: the toothed segment is arrayed facing away from the center of rotation of the actuation lever, and the toothed segment is arrayed convexly away from the center of rotation. 
         [0023]    According to another aspect of the proposed invention there is further provided a drive, wherein: the toothed segment operatively cooperates with the spindle, and the toothed segment operatively cooperates with spindle through at least one of a toothed rack and a worm element. 
         [0024]    According to another aspect of the proposed invention there is further provided a drive, wherein: the actuation lever operably engages with a spindle nut, the spindle nut operably interengaging the rotating spindle in such a manner allowing the spindle nut to rotate un unison with the rotation spindle, and the spindle driven by the electromotor. 
         [0025]    The above, and other aspects, features and advantages of the present invention will become apparent from the following description read in conduction with the accompanying drawings, in which like reference numerals designate the same elements. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0026]      FIG. 1  shows a perspective view of a first brake caliper type with an actuation device closed by a housing and with a drive, that is also closed, in accordance with a first exemplary embodiment. 
           [0027]      FIG. 2  shows a perspective view of the first brake caliper type with the actuation device and the drive from  FIG. 1 , whereby the housing is shown open and without a housing cover. 
           [0028]      FIG. 3  shows a perspective view of the first brake caliper type with the actuation device and the drive from  FIG. 1 , whereby a worm-spindle transmission connected between the actuation device and the drive is shown in an exploded view. 
           [0029]      FIG. 4  shows a perspective view of a second brake caliper type with an actuation device in a deviating alignment and with a drive in accordance with the first exemplary embodiment and closed in another housing. 
           [0030]      FIG. 5  shows a perspective view of the second brake caliper type with the actuation device and the drive from  FIG. 4 , whereby the other housing is shown open and without housing cover. 
           [0031]      FIG. 6  shows a perspective view of the second brake caliper type with the actuation device and the drive from  FIG. 4 , whereby the worm-spindle transmission connected in analogy with  FIG. 3  between the actuation device and the drive is shown in an exploded view. 
           [0032]      FIG. 7  shows a perspective view of the first brake caliper type with another actuation device closed by a housing and with a drive that is also closed and is in accordance with a second exemplary embodiment. 
           [0033]      FIG. 8  shows a perspective view of the first brake caliper type with the actuation device and the drive from  FIG. 7 , whereby the housing is shown open and without housing cover. 
           [0034]      FIG. 9  shows a perspective view of the first brake caliper type with the actuation device and the drive from  FIG. 7 , whereby the worm-spindle transmission connected in analogy with  FIG. 3  between the actuation device and the drive is shown in an exploded view. 
           [0035]      FIG. 10  shows another example of a drive in accordance with the invention. 
           [0036]      FIG. 11  shows still another example of a drive in accordance with the invention. 
       
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
       [0037]    Reference will now be made in detail to several embodiments of the invention that are illustrated in the accompanying drawings. Wherever possible, same or similar reference numerals are used in the drawings and the description to refer to the same or like parts or steps. The drawings are in simplified form and are not to precise scale. For purposes of convenience and clarity only, directional terms, such as top, bottom, up, down, over, above, and below may be used with respect to the drawings. These and similar directional tuns should not be construed to limit the scope of the invention in any manner. The words “connect,” “couple,” and “operable” and similar terms with their inflectional morphemes do not necessarily denote direct and immediate connections, but also include connections through mediate elements or devices. 
         [0038]      FIGS. 1 to 3  and  7  to  9  show a first type of a brake caliper  10 . This type has a housing  20  aligned parallel to a brake piston axis A of a brake piston  11  not shown in detail. As shaft with a center of rotation  42  exits from the housing  20  along the brake piston axis A facing away from the brake piston. The shaft can be rotated by an actuation lever  40  about the center of rotation  42 . 
         [0039]    A rotation of the shaft brings about a linear movement of the brake piston not visible in the drawings and seated in the housing, as a result of which a brake lining which is also not visible is pressed against a brake disk which is not visible in the drawings. 
         [0040]      FIGS. 4 to 6  shows second type of a brake caliper  10 ′ with a housing  20 ′. However, now the housing  20 ′ is aligned transversely to the brake piston axis A′. An appropriately attached actuation lever  40  can be constructed just as in the case of the first brake caliper of  FIGS. 1-3 . This lever also rotates in the current example of the second brake caliper  10 ′ about the center of rotation  42  of the cup  20 ′. However, the center of rotation  42  is located at a different position since the cup  20 ′ is pivotably arranged in comparison to the cup  20 . 
         [0041]    The actuation lever  40 ,  40 ′ is shown in two exemplary embodiments. The  FIGS. 1 to 6  shows the first exemplary embodiment, in which the actuation lever  40  has an oblong hole  41 . The  FIGS. 7 to 9  show the second exemplary embodiment whose actuation lever  40 ′ has a toothed segment  44 ′ instead of the oblong hole  41 . The same reference numbers are generally used for the same parts in the figures. For the sake of better clarity not all reference numbers are entered in all figures. 
         [0042]      FIG. 1  shows a brake caliper  10  in accordance with the first type. The driver of a vehicle actuates a traditional parking brake in the brake caliper  10  by pulling on a brake lever. This linear force is transferred in the case of the brake caliper  10  customarily by a Bowden wire by the brake lever onto the lever arm of the actuation lever  40 . The actuation lever  40  rotates as a consequence about an axis of rotation aligned vertically to the lever arm of the actuation lever  40 . The rotary motion of the actuation lever  40  is converted in the brake caliper  10  into a linear motion of a brake piston  11 . In the brake caliper  10  the brake piston  11  presses at least one brake shoe against a brake disk that rotates with a wheel of a vehicle when actuated by the actuation lever  40 . 
         [0043]    The traction on the brake lever and the transfer of force by the Bowden wire, which is also not shown, are replaced in a drive in accordance with the invention, as it is shown in  FIG. 1 , by an electromotor  32  and a transmission coupled to it, especially a worm-spindle transmission  3 . The electromotor  32  is accordingly coupled via the worm-spindle transmission  3  to the actuation lever  40 . A common housing  33 ,  43  covers the electromotor  32 , the worm-spindle transmission  3  and the actuation lever  40 . A separate motor housing  33 ′ in accordance with  FIG. 4  can also be used instead. Also, the housing  43  could be separately designed as a lever housing. A deviating form of the housing in the area of the actuation lever  40 ′ is represented by the lever housing  43 ′ in the  FIGS. 7 to 9 . 
         [0044]    The  FIGS. 2 ,  5  and  8  allow views into the interior of the particular housing  33 ,  33 ′,  33 ″,  43 ,  43 ′. By way of supplementation the worm-spindle transmission  3 , that is constructed in a similar manner in all views, is shown in the exploded views of  FIGS. 3 ,  6  and  9  with its components worm  31 , spindle nut  37  and spindle  30  named along the flow of force and of moment. The worm  31  rotates with a motor shaft M of the electromotor  32  and is fastened in addition on its output shaft  36  in such a manner that it rotates in unison with it. The output shaft  36  can also be constructed distally directly as a worm. The worm  31  drives the spindle nut  37  so that the latter rotates about a spindle axis B that can be aligned at any angle to the motor shaft M. 
         [0045]    The spindle nut  37  is supported axially and radially in a stationary manner. In addition, butting disks or butting sleeves assume the function of an axial support  34  and/or radial support  35 . These functions can of course also be distributed onto several parts. Other disks  38  can be provided, for example, for the compensation of play or for the further support and improvement of the efficiency of the spindle  30 . Supported and driven in such a stationary but rotatable manner, the spindle nut  37  drives the spindle  30  along the spindle axis B through its inside. To this end the spindle nut  37  has a thread on the inside that cooperates with the spindle  30 . 
         [0046]    The electromotor  32  for driving the worm-spindle transmission  3  is fastened according to the  FIGS. 1 to 3  with its housing  33  on the outside via the transmission housing on the brake caliper  10 . Its output shaft  36  exits along the motor axis M transversely to the brake piston axis A of the brake piston  10 . 
         [0047]    The spindle  30  is coupled to the actuation lever  40 . It is pivotably received to this end in the oblong hole  41  provided in the actuation lever  40 . If the spindle nut  37  is rotated, it shifts the spindle  30  along the spindle axis B and presses against the lever arm of the actuation lever  40  so that the actuation lever  40  rotates about its center of rotation  42 . 
         [0048]    The center of rotation  42  advantageously rests in the exemplary embodiments shown on the motor axis M. It can also rest somewhere else. According to the  FIGS. 1 to 9  the corresponding axis or rotation stands vertically on the lever arm of the actuation lever  40 ,  40 ′ and also vertically on the motor axis M. 
         [0049]    The oblong hole  41  is aligned with its longitudinal axis onto the center of rotation  42 . Consequently, a receptacle of the necessarily pivotably spindle  30  in the longitudinal hole  41  can move in they oblong hole  41  toward the center of rotation  42  when the brake is applied. For this, the driver does not pull on a brake lever as usual. Instead of this, for example, pressing a button for supplying the electromotor with current is sufficient. 
         [0050]    The receptacle of the spindle  30  moves in the oblong hole  41  away from the center of rotation  42  when the brake is loosened. Of course, the system also functions exactly in the inverse manner. 
         [0051]    The customary Bowden wire  20  is—as previously described—replaced by the electromotor drive with a transmission unit that attacks the activation lever  40 ,  40 ′. Alternatively, if a Bowden wire is to be retained, an attack by the spindle  30  or the transmission unit on the Bowden wire or the activation lever  40 ,  40 ′ can additionally take place. 
         [0052]      FIGS. 7 to 9  show an alternative coupling of the spindle  30  to the activation lever  40 ′. The spindle nut  37  rests positively in this example on the spindle  30 . The spindle nut  37  is put in rotation by the drive worm  31  of the motor  32  so that the spindle  30  moves into the one or the other longitudinal direction as a function of the direction of rotation. The spindle  30  moved longitudinally by the motor  32  meshes on its upper end, that is shown in  FIG. 8  and is constructed as a toothed rack  39 , with the arched toothed segment  44 ′, that is preferably formed in one piece on the actuation lever  40 ′. For this, the actuation lever  40 ′ has a toothed segment  44 ′ constructed in an arched shape—convex relative to the center of rotation  42 —facing away from its center of rotation  42 ′. The toothed segment  44 ′ rolls off over the rise of the spindle  30  with the spindle  30  constructed on its end as a straight or obliquely toothed rack  39 . In the latter case of the oblique toothing the rise of the spindle  30  can be utilized, which makes a separately attached oblique toothing no longer necessary. The actuation lever  40 ′ is rotated about its center of rotation  42  by the previously described embodiment. Such an actuation lever  40 ′ could of course also be selected in a drive in accordance with the invention for the second brake caliper type  10 ′. 
         [0053]    Another mechanical coupling of the spindle  30  to the actuation lever  40 ′ consists of a rotating spindle  30  with a spindle nut. The exemplary embodiment of  FIG. 10  differs from the  FIGS. 7 to 9  in that instead of a toothed rack  39  on the end of the spindle  30  a worm is provided that positively rotates with the spindle  30 . 
         [0054]    Yet another mechanical coupling of the output shaft  36  of the motor  32  to the actuation lever  40 ′ consists in the embodiment described in  FIG. 11 . There, the end of the actuation lever  40 ′ is connected in an articulated manner to a holding element  50 . The upper end of the spindle  30  is screwed into this holding element  50 . The spindle  30  is again able to move in rotation but otherwise, however, is arranged in a fixed manner and thus cannot move longitudinally. To this end the spindle nut  37  rests on the spindle  30  in such a manner that it can rotate in unison with it in an already known manner. The spindle nut  37  meshes with the worm  31  so that during the driving of the electromotor  32  the spindle  30  rotates to the left or to the right as a function of the direction of rotation of the output shaft  36 . During the one direction of rotation of the spindle  30  the holding element  50  is screwed further onto the spindle  30  and as a consequence the actuation lever  40 ′ is drawn downward. If the spindle  30  moves in the opposite direction the holding element  50  is lifted off further and further from the spindle  30  so that the actuation lever  40 ′ is pivoted upward. 
         [0055]    A drive in accordance with the invention is suitable for being jointly assembled with in particular purely mechanical brake calipers. In addition, a use of such drives for retrofitting existing brake systems in motor vehicles is possible. 
       LIST OF REFERENCE NUMERALS  
       [0000]    
       
           3  worm-spindle transmission 
           10 ,  10 ′ brake calipers 
           11 ,  11 ′ brake piston 
           20 ,  20 ′ housing 
           30  spindle 
           31  worm 
           32  electromotor 
           33 ,  33 ′,  33 ″ motor housing 
           34  axial support 
           35  radial support 
           36  output shaft 
           37  spindle nut 
           38  disk 
           39  toothed rack 
           39   a  worm 
           40 ,  40 ′ actuation lever 
           41  oblong hole 
           42 .  42 ′ center of rotation 
           43 ,  43 ′ lever housing 
           44 ′ toothed segment 
           50  holding element 
         A, A′ brake piston axis 
         B, B′ spindle axis 
         M, M′ motor axis 
       
     
         [0080]    In the claims, means or step-plus-function clauses are intended to cover the structures described or suggested herein as performing the recited function and not only structural equivalents but also equivalent structures. Thus, for example, although a nail, a screw, and a bolt may not be structural equivalents in that a nail relies on friction between a wooden part and a cylindrical surface, a screw&#39;s helical surface positively engages the wooden part, and a bolt&#39;s head and nut compress opposite sides of a wooden part, in the environment of fastening wooden parts, a nail, a screw, and a bolt may be readily understood by those skilled in the art as equivalent structures. 
         [0081]    Having described at least one of the preferred embodiments of the present invention with reference to the accompanying drawings, it is to be understood that the invention is not limited to those precise embodiments, and that various changes, modifications, and adaptations may be effected therein by one skilled in the art without departing from the scope or spirit of the invention as defined in the appended