Abstract:
The invention relates to a load torque lock ( 1 ) comprising a sling element ( 12 ) that frictionally interacts with a brake component ( 13 ) for blocking a torque, and a drive wheel ( 14 ) that is coupled in a torque transferring manner to a carrier ( 15; 15   a ) having at least one contact area ( 25 ) to the sling element ( 12 ) and engaging axially in the drive wheel ( 14 ), by means of which a torque to be blocked can be initiated in the sling element ( 12 ). According to the invention, the carrier ( 15; 15   a ) has means for reducing the bending tension in the at least one contact region ( 25 ).

Description:
BACKGROUND OF THE INVENTION 
       [0001]    The invention relates to a load torque lock, in particular for automotive applications, and to an apparatus, in particular an auxiliary and comfort apparatus, preferably for automotive applications, having a load torque lock. 
         [0002]    Known from DE 197 53 106 C2 is a load torque lock which is incorporated in a drive train and which automatically blocks torques induced by the output drive when the drive is at a standstill. The torques induced from the drive side are transmitted in both directions. In order to block the torque on the output side a sling spring interacts frictionally with a brake component. The known load torque lock has proved effective. However, efforts are being made to make the load torque lock more robust, since deformations of the plastics material can occur, in particular in the contact region of the sling spring with the plastics carrier, which deformations are caused by surface pressures arising in operation and by relatively high bending stresses. 
       SUMMARY OF THE INVENTION 
       [0003]    It is therefore the object of the invention to specify a robust load torque lock which has an increased service life. The load torque lock should preferably be inexpensive to produce and, further preferably, should be of lightweight construction. It is also the object of the invention to specify an apparatus having a correspondingly optimized load torque lock. 
         [0004]    The invention is based on the concept of equipping the at least one contact region of the carrier, against which the sling element bears or is supported in the event of blocking, with means which bring about a reduction of the bending stress in the at least one contact region. 
         [0005]    Especially preferred is an embodiment in which two contact regions of the carrier, which each interact with a respective free end of the sling element, are made at least partially of metal. By making the at least one contact region of the carrier at least partially of metal, inadmissible surface pressures and high bending stress can be avoided, whereby damage to the carrier when a torque to be blocked is induced can be reliably prevented. 
         [0006]    A load torque lock configured according to the concept of the invention is especially suited to automotive applications such as sliding roof drives, seat adjusters, window regulators, windshield wiper drives, transmission and clutch actuators and electric steering systems, and for use in actuators generally. However, the application of a load torque lock configured according to the concept of the invention is not restricted hereto and can be used in principle in all motors, drives and machines. 
         [0007]    Very especially preferred is an embodiment of the load torque lock in which the carrier coupled to the drive wheel, preferably by axial engagement, has a multi-part configuration, preferably such that it comprises a plastics main body to which at least one metal element is fixed to form at least one contact region. Very especially preferably, the carrier or main body is a plastics injection molding. The multi-part configuration of the carrier (plastics and metal protection) makes it possible to distribute the contact pressure on the sling element in such a manner that the main body of plastics material withstands the loadings and, overall, a system which can be produced at low cost is obtained. 
         [0008]    With regard to the manner in which the at least one metal element is fixed to the plastics portion of the carrier, preferably to a main body of the carrier, there are various possibilities. For example, it is possible to inject a plastics injection molding compound partially around the metal element during the injection molding process and to fix the metal element in this way. In an alternative configuration, the metal element may be latched or clipped to the plastics portion and may subsequently be fastened thereto in a simple manner. 
         [0009]    With regard to the configuration of the metal element there are also various possibilities. For example, it is possible to configure the metal element as a shell or as a pot closed on one side, in particular at the bottom, and to arrange the metal element in such a manner that it at least partially covers or encloses the plastics portion. It is also possible to configure the metal element in such a manner that the plastics material of the carrier is injected at least partially around the metal element. 
         [0010]    Furthermore, there are also various possibilities with regard to the concrete configuration of the sling element. Especially preferred is an embodiment in which the sling element is in the form of an, in particular metal, sling spring, the sling spring preferably interacting, by means of two preferably inwardly bent, axially spaced free ends, with respective metal contact regions of the carrier. Alternative embodiments of the sling element are also possible, for example as a sling link chain, a sling strap, a sling cable or the like. The sling element is preferably arranged in such a manner that its free ends can be moved towards and away from one another in the circumferential direction in order to bring the sling element frictionally into frictional engagement with the brake component on the radially inner side or the radially outer side in the event of blocking. 
         [0011]    There are also various possibilities with regard to the configuration of the brake component. It is especially preferred if the brake component has a cylindrical friction surface (inner or outer cylindrical surface), it being possible to implement both an embodiment in which the sling element interacts with the inner circumference of the brake component, that is, with a friction surface formed on the inner circumference, and an embodiment in which the sling element surrounds the brake component and in this case interacts frictionally by frictional engagement with an outer circumference of the brake component in the event of blocking. 
         [0012]    The invention also leads to an apparatus, preferably an auxiliary or comfort apparatus, in particular for automotive applications. The apparatus may be, for example, a motor and/or a machine. Very especially preferably, it is an actuating drive, such as a sliding roof drive, a window regulator drive, a seat adjuster drive, a windshield wiper drive or a transmission and/or clutch actuator. It may also apply to an electric steering system for motor vehicles, etc. The apparatus is distinguished in that it is provided with at least one load torque lock configured according to the concept of the invention. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0013]    Further advantages, features and details of the invention are apparent from the following description of preferred exemplary embodiments and with reference to the drawings, in which: 
           [0014]      FIG. 1  shows in a perspective, partly sectional representation a possible embodiment of a load torque lock (locking coupling), 
           [0015]      FIG. 2  is an exploded representation of a carrier consisting of a plastics main body and two clip-on metal elements, 
           [0016]      FIG. 3  is a side view of a fully assembled carrier, 
           [0017]      FIG. 4  is a side view of the assembled carrier rotated through 180° in relation to  FIG. 3 , 
           [0018]      FIG. 5  shows a part of the load torque lock in a partially sectional perspective view with a modified metal element, 
           [0019]      FIG. 6  shows the metal element according to  FIG. 5  in a perspective view, 
           [0020]      FIG. 7  shows a modified carrier in a perspective view, 
           [0021]      FIG. 8  shows the carrier according to  FIG. 7  with an additional metal element, also in a perspective view, 
           [0022]      FIG. 9  shows a further modified metal element with a support section in a perspective representation, 
           [0023]      FIG. 10  shows the metal element according to  FIG. 10  when installed on the carrier, in a perspective view, 
           [0024]      FIG. 11  shows a further modified metal element with a support section in a perspective representation, 
           [0025]      FIG. 12  shows the metal element according to  FIG. 11  when installed on the carrier, in a perspective view, 
           [0026]      FIG. 13  shows a further modified metal element with a support section in a perspective representation, and 
           [0027]      FIG. 14  shows a metal element according to  FIG. 13  when installed on the carrier, in a perspective view. 
       
    
    
     DETAILED DESCRIPTION 
       [0028]    In the figures, identical elements and elements having the same function are designated by the same reference numerals. 
         [0029]      FIG. 1  shows a possible embodiment of a permanently coupled, that is, non-disengageable load torque lock  1 . This includes a sling element  12  in the form of a metal sling spring. The sling element  12  is received in a hollow-cylindrical brake component  13  and, in the event of blocking, interacts by means of its outer circumference with the inner circumferential surface of the brake component  13 . In an alternative variant, which is known per se and is not represented, the sling element  12  interacts by means of its inner circumference with the preferably cylindrical outer circumference of a brake component. 
         [0030]    The load torque lock  1  includes a drive wheel  14  in the form of a worm gear which is drivable in both directions of rotation by an electric-motor driven transmission worm (not shown). The drive wheel  14  is coupled to a carrier  15  which engages in the axial direction in receiving pockets  16  of the drive wheel  14 . The carrier  15  serves in its turn to transmit the torque induced on the drive side to an adjusting mechanism, for example a cable control mechanism of a window regulator drive. 
         [0031]    The sling element  12  has two free ends spaced from one another in the axial direction, of which only an upper, radially inwardly bent free end  17  is shown in  FIG. 1 . The drive wheel  14  interacts with the carrier  15  in such a way that if a torque is induced on the drive side, that is, by the drive wheel  14 , it is transmitted to the carrier  15 . The sling element  12  is then entrained, that is, it is displaced together with the drive wheel  14  and the carrier  15  relative to the fixed brake component  13 . In the event that torque is induced on the output side, that is, via the carrier  15 , the free ends  17  of the sling element  12  are moved apart in such a manner that the outer circumference of the sling element  12  is increased, whereby the sling element  12  interacts frictionally by means of its outer circumference with the inner circumference of the brake component  13 , and thus blocks the torque induced on the output side, which torque, therefore, is not transmitted to the drive wheel  14  and thus in the direction of a drive motor, in particular of an electric motor (not shown). 
         [0032]    In a variant (not shown) of a load torque lock  1  in which the sling element  12  interacts with an outer circumference of a brake component  13 , the free ends  17  must be moved with respect to one another as described previously, but in the reverse direction, in order to produce the braking effect. 
         [0033]    In order to increase the robustness of the load torque lock  1 , a metal element  20  is provided on each axial projection  18  (only one is shown) by means of which the carrier  15  engages axially in the receiving pockets  16 , against which metal element  20  a respective free end  17  of the sling element  12  bears in order to block the torque induced on the output side. 
         [0034]    In the following description a first preferred embodiment of the multi-part carrier  15  is explained in detail with reference to the perspective representations in  FIG. 2  to  FIG. 4 . 
         [0035]      FIG. 2  shows in a perspective representation the carrier  15  of multi-part construction. This carrier  15  includes a main body  22  of plastics material produced as an injection molding. In an upper portion the main body  22  is provided with an external toothing  23  in order to transmit, for example to a cable control mechanism, the torque transmitted by the drive wheel  14  (see  FIG. 1 ) to the carrier  15 . 
         [0036]    The carrier  15 , more precisely the main body  22 , has two peg-like projections  18  spaced from one another by 180° in the circumferential direction, which serve to transmit torque, on the one hand imparting a torque induced on the output side to the sling element  12  as shown in  FIG. 1  and, on the other, receiving a torque induced on the drive side via the drive wheel  14  (see  FIG. 1 ). 
         [0037]    The carrier  15  further includes two clip-on metal elements  20  to be fixed to the projections  18  for the purpose of increasing the robustness of the multi-part carrier  15 . Contrary to the prior art, the free ends  17  of the sling element  12  do not bear directly on the projections  18 , but only indirectly thereon via the metal elements  9 , which interact immediately, that is, directly, with the free ends  17  of the sling element  12 . 
         [0038]    In  FIG. 3  and  FIG. 4  the carrier  15  is in each case represented in the fully assembled state. It can be seen that the metal elements  20  are arranged offset to one another in the axial direction. This is explained by the fact that the free ends  17  of the sling element  12 , in the form of a sling spring, are also spaced from one another in the axial direction. 
         [0039]    The metal elements  20  each encompass a plastics portion  13  of the main body  22  formed by a respective portion of a projection. 
         [0040]    As is apparent from  FIG. 4 , the metal elements  20  on a common side each form a contact region  25  for direct abutment against a respective free end  17  of the sling element  12 . In this way inadmissible surface pressures, of the kind which might occur in the event of blocking with purely plastics projections  18 , can be reliably avoided. Furthermore, the metal elements  20  reduce the bending stresses in the projections  18 , in that the forces exerted by the free ends  17  are imparted over a larger area to the projections  18 . 
         [0041]      FIGS. 5 and 6  show a modified metal element  20   a . The metal element  20   a  has a plate-like middle region  27  with a through-opening  28 . The metal element  20   a  is mounted on a drive pin  30  of the carrier  15  by means of the through-opening  28 . The middle region  27  is arranged in a plane below the carrier  15  and its projections  18 . Two contact sections  31  arranged offset to one another by 180° project from the outer portions of the middle region  27  in the direction of the projections  18 , the two contact sections  31  being configured to have different lengths corresponding to the different axial arrangement of the two free ends  17  of the sling element  12 . In this case the contact sections  31  are arranged between the free ends  17  and the projections  18 , in the receiving pockets  16  of the carrier. 
         [0042]      FIG. 7  shows a modified carrier  15   a . The carrier  15   a  has means for reducing the bending stresses resulting from the forces induced by the free ends  17  of the sling element  12  in the carrier  15   a . These means consist in a particular geometrical configuration of the carrier  15   a.    
         [0043]    To this effect the carrier  15   a  has a modified projection  18   a  which, viewed in a plane transverse to the longitudinal direction of the carrier  15   a , occupies an angular range of at least 10°, in particular from 30° to 120°, and up to the approximately 180° illustrated. In this case the angular range referred to is arrived at according to the stress or the forces to be transmitted and, inter alia, as a function of the material used. What is essential to the carrier  15   a  is that the two end faces  33 ,  34  delimiting the projection  18   a  serve as mating or abutment faces for the two free ends  17  of the sling element  12 . As a result of the usually wider configuration of the projection  18   a  as compared to the projections  18 , in particular the bending stress of the projection  18   a  on the base  35  of the carrier  15   a  is reduced. In addition, it may preferably be provided for this purpose that a radius  36  is formed at least in the respective transitional regions between the base  35  and the end faces  33 ,  34 , which radius  36  further reduces the bending stress or the notch effect. 
         [0044]      FIG. 8  shows the carrier  15   a  interacting additionally with a metal element  20   b  which corresponds substantially to the metal element  20  represented in  FIGS. 2 to 4 . 
         [0045]      FIGS. 9 and 10  show a modified metal element  20   c  for use on the carrier  15   a  (alternatively, an insert on the carrier  15  is also possible for this purpose). In this case the metal element  20   c  has an additional support section  38  which passes through an opening  39  formed in the carrier  15   a  and rests against the underside  40  of the carrier  15   a . A bending moment transmitted by the free end  17  of the sling element  12  is thereby transmitted via the support section  38  to the carrier  15   a , at least partially unloading the projection  18   a.    
         [0046]      FIGS. 11 and 12  show a modified metal element  20   d  for use on the carrier  15 . In this case the metal element  20   d  has an arched configuration and encompasses the projection  18  of the carrier  15 . In addition, the metal element  20   d  has on the side opposite the contact region  25  a support section  38   d  which rests against the upper side  41  of the carrier  15 . 
         [0047]    The modified metal element  20   e  for the carrier  15  shown in  FIGS. 13 and 14  represents a combination of the metal elements  20   c  and  20   d . To this end the metal element  20   e  has two support regions  43 ,  44  arranged on opposite sides, which interact with the upper and lower sides of the carrier  15  respectively. 
         [0048]    It will be mentioned additionally that the metal elements  20 ,  20   a  to  20   e  are produced, in particular, from sheet metal as punched and bent parts. Furthermore, it may be provided in the case of the metal elements  20   c ,  20   d ,  20   e  that the support sections  38 ,  38   d ,  43 ,  44  are also enclosed by the plastics material of the carrier  15 ,  15   a . The metal elements  20   c ,  20   d ,  20   e  are thereby additionally anchored in the carrier  15 ,  15   a , so that additional measures for retaining them on the carrier  15 ,  15   a  may optionally be dispensed with.