Patent Publication Number: US-7905523-B2

Title: Motor vehicle lock

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to a motor vehicle lock and, more specifically, to the use of a motor to open the ratchet of a motor vehicle lock. 
     2. Description of Related Art 
     A vehicle lock which is known, for example, from published German Patent Application DE 196 14 122 A1, (corresponding to U.S. Pat. No. 5,934,717), and which is popular for motor vehicle side doors, has a latch and an assigned hook-shaped ratchet. The latch can hold or secure a striker and is, for its part, blocked by the ratchet which can engage the latch in a main catch position and a preliminary catch position. 
     Published German Patent Application DE 20 01 653 A shows a motor vehicle lock with a latch and an assigned (i.e., associated) ratchet. The ratchet is not hook-shaped, but instead made in the manner of a swiveling pin. The pin has a recess that forms an engagement section which can be moved into blocking engagement with the latch by swiveling the pin. The actuation of the ratchet, which has been formed in this way, takes place via a conventional lever arrangement. 
     Published German Patent Application DE 101 11 085 A1 discloses a motor vehicle lock with a latch and a ratchet, which can be actuated, for example, by an electric motor via a worm gear. This gear requires high precision of all components and therefore high production costs. In practice, it has been shown that a worm gear tends to premature failure. Another disadvantage is that a worm gear transfers the motor noise to all other components so that the motor vehicle lock exhibits undesirably high operating noise. 
     Published German Patent Application DE 196 04 724 A1 discloses a motor vehicle lock with a latch and an assigned ratchet. A flexible traction element called a cable pull connects the ratchet to the handle so that the ratchet can be opened by manual actuation of the handle. As such, there is no motorized driving of the ratchet. 
     Published German Patent Application DE 102 00 551 A1 discloses a motor vehicle lock with a swiveling catch that is used to directly secure or hold the striker in an inlet slot of the motor vehicle lock in a locked or blocked state. The catch can be swiveled manually, or by motor, via an opening element in the opening direction. The opening element can have a sheathed cable. Specific instructions for implementation of an opening drive by means of a flexible traction means are not provided. 
     SUMMARY OF THE INVENTION 
     An object of the present invention is directed to a motor vehicle lock and the use of a motor for opening the ratchet of a motor vehicle lock so that a simple and economical structure, with few components and/or simple triggering is enabled, and a durable structure which is subject only to little wear can be implemented with little operating noise. 
     The present invention provides a flexible traction means, especially a cable or belt, which can be wound up preferably directly by the motor or the driven shaft of the motor and which acts directly or indirectly on the ratchet. In particular, the ratchet can be opened against a spring force by the traction means. This enables a simple and economical structure, since only a few components and no especially precision-manufactured components are necessary. Another advantage of the present invention resides in the fact that the operating noise of the motor is not transferred by the traction means or is transferred only to a small degree to the other parts. Another advantage resides in the fact that that precision gear engagement, as in a worm gear, is not necessary, so that wear problems in this respect can be avoided. Finally, with the use of the aforementioned traction means for drive engineering purposes, invulnerability to fouling is ensured. Moreover, the greasing which is necessary in toothed gearing is completely eliminated. 
     Another advantage of the present invention, is that low self-locking can be accomplished. After the motor is turned off, the traction means can be automatically unwound again by spring force and, thus, the ratchet can be swiveled to be able to move back into its blocking position. Preferably, the reset force is produced by a spring which is present anyway and for example is assigned to the ratchet or a rocker arm or the like which is coupled to the ratchet. In this way, both a simple and thus economical structure and also simple triggering are enabled. 
     Preferably, on the ratchet or the assigned rocker arm, there is a deflection roller for the traction means and the free end of the traction means is thrust for example against the housing of the motor vehicle lock. Thus speed transformation is easily achieved, and by the corresponding choice of the geometrical ratios and arrangements a transmission ratio which is adapted to need can be implemented. 
     An especially durable arrangement arises by the connection, which has been formed by the traction means, between the motor and the ratchet (a direct connection without an interposed deflection lever). Matching of the speed transformation can be achieved by the fundamentally present possibility of variation of the diameter of the driven shaft. 
     Outfitting the ratchet, with an essentially cylindrical section, with the traction means, attached to its jacket surface, leads to an especially compact and economical version. The traction means is then wound and unwound to a certain extent over a certain angle range when the ratchet is moved. The angle range is preferably distinctly less than 180°. 
     Other advantages, features, properties and aspects of this invention derive from the following description of preferred embodiments. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  shows a schematic perspective view of a motor vehicle with several motor vehicle locks; 
         FIG. 2  shows a schematic view of the motor vehicle lock of the invention in the locked state; 
         FIG. 3  shows a schematic of the motor vehicle lock of the invention as shown in  FIG. 2  in the unlocked or opened state; 
         FIG. 4  shows a schematic of the motor vehicle lock of the invention according to a second embodiment in the locked state; 
         FIG. 5  shows an injection molding with the traction means for the motor vehicle lock as shown in  FIG. 4 ; 
         FIG. 6  shows a schematic of the motor vehicle lock of the invention according to a third embodiment in the locked state; 
         FIG. 7  shows a schematic of the motor vehicle lock of the invention as shown in  FIG. 6  in the unlocked or opened state; and 
         FIG. 8  shows a schematic extract of the motor vehicle lock of the invention according to a fourth embodiment in the locked state. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     In the figures the same reference numbers are used for the same or similar parts, the corresponding or comparable properties and advantages being achieved even if a repeated description is omitted. 
       FIG. 1  schematically shows a motor vehicle  1  with several motor vehicle locks  2 , such as side door locks, a hood lock, and the like. The arrows in  FIG. 1  indicate the approximate installation position of the illustrated motor vehicle locks  2  in the motor vehicle  1 . The term “motor vehicle lock” is defined primarily as the door lock of a motor vehicle. But it can also be a trunk lock, a hood lock, a hatch lock or the like of a motor vehicle. The structure of a motor vehicle lock  2  of the present invention is detailed below. 
       FIG. 2  schematically shows one exemplary embodiment of a motor vehicle lock  2  shown in a locked state. The motor vehicle lock  2  has a latch  3  which is a rotary latch, an assigned ratchet  4  and a motor  5  for opening the ratchet  4 . The ratchet  4  can secure the latch  3 , preferably in a main catch position and a preliminary catch position, as is conventional in most motor vehicle door locks, hereinafter called the blocked position, and thus can lock the motor vehicle lock  2 . The ratchet  4  can be moved (e.g., swiveled) into a non-engagement position, out of the blocked position in which the ratchet  4  is engaged with the latch  3 , or can engage it. This is hereinafter called opening or the open position, of the ratchet  4 . 
     In accordance with this exemplary embodiment, the motor  5  is, for example, an electric motor. However, it can also be any other suitable drive. The motor vehicle lock  2  has a flexible traction means  6  so that the motor  5  can actuate, (especially open) the ratchet  4  by the traction means  6 . 
     According to an exemplary embodiment of the present invention, the traction means  6  can act directly on the ratchet  4 . This is explained in detail in conjunction with the embodiments shown in  FIGS. 6 to 8 . In the embodiment shown in  FIG. 2 , however, the traction means  6  acts indirectly on the ratchet  4 , via a rocker arm  7  which is assigned to the ratchet  4 . 
     The traction means  6  is preferably made as a cable, belt or chain. Structurally, the traction means  6  has a round or flat cross section, and can be made selectively in one piece or with several members. The traction means  6  can be formed from several preferably stranded filaments or strands. In this embodiment the traction means  6  is a cable. Moreover, the traction means  6  is preferably made of plastic and/or steel. According to another exemplary embodiment, the traction means  6  is a flat plastic or a steel belt. 
     The traction means  6  can be wound up by the motor  5 , preferably gearlessly, directly onto the driven shaft  8  of the motor  5 . To do this, the traction means  6  is connected, positively or nonpositively, to the driven shaft  8  at one end. Preferably, the traction means  6  is injected, or pressed for example, into a receiving part  9  which is permanently connected to the driven shaft  8 , or is in some other manner, attached thereto. The receiving part  9  is preferably a flange and forms an axial stop for winding the traction means  6  onto the driven shaft  8 . 
     The driven shaft  8  constitutes, for example, a shaft of the motor  5  which is made relatively long. But the driven shaft  8  can also be a lengthened or include an additional shaft segment. The additional shaft segment would be flanged to the actual motor shaft in the motor  5  or be directly connected to the actual motor shaft in some other way. If necessary, the driven shaft  8  can also be driven by the motor  5  via gearing (not shown). In this case, the gearing is preferably integrated into the motor  5  or flanged directly to it. As such, a geared motor is preferably employed. 
     The motor vehicle lock  2  can be made so that the traction means  6  is wound in a helical line (only in one layer) onto the driven shaft  8 . To achieve this, the traction means  6 , depending on the swivel position of the ratchet  4  or of the rocker arm  7  during the wind-up process, is accordingly laterally offset or guided. Thus, minimum wear of the traction means  6  and precision, repeatable actuating behavior of the drive train which has been formed, are enabled (see  FIGS. 2 and 3 ). 
     Preferably, on the driven shaft  8 , a winding stop  10  is spaced apart from the receiving part  9  so that, between the receiving part  9  and the winding stop  10 , the traction means  6  can be wound onto the driven shaft  8 . In particular, the winding stop  10  is, in accordance with one embodiment of the invention, a flange. Thus, reliable guidance of the traction means  6  on the driven shaft  8  is provided. 
     Preferably, the traction means  6  forms a cable pull  11 . For this purpose, the traction means  6  is guided around a deflection roller  12  which is used as a “loose roller” on the ratchet  4  or, as in the embodiment shown in  FIGS. 2 and 3 , on the rocker arm  7 . With its other or free end, the traction means  6  is thrust against the motor vehicle lock  2  or its housing  13 . Preferably, the traction means  6  is suspended or pressed on the housing  13 , especially on a correspondingly made bearing block or the like, in order to enable simple installation. However, the traction means  6  can, if necessary, also be injected with one end area, for example, or can be connected in some other way to the housing  13 . 
     Depending on the geometrical arrangement of the components to one another and depending on the direction of the traction means  6 , which runs from the drive shaft  8  to the deflection roller  12  and from the deflection roller  12  to the housing  13 , and on the direction of motion (here the direction of swiveling motion) of the rocker arm  7  (or of the ratchet  4 ) there is a gear reduction which can be adapted as desired and can be varied depending on the swivel position, with the opening motion. 
     In particular, the cable pull  11  proceeding from the blocked position first forms relatively large gear reduction of the motor motion in order to be able to apply a large opening force or lifting force to the ratchet  4 , which is optionally heavily loaded by the latch  3 , and/or in order to overcome the abrasion forces. As opening progresses further, the gear reduction ratio decreases in order to enable a relatively prompt opening of the ratchet  4 . 
     The ratchet  4  is preferably pretensioned by spring force into the blocked position. The rocker arm  7  is likewise pretensioned into the position shown in  FIG. 2 . This allows the engagement or the blocking function of the ratchet  4 , and the rocker arm  7  to be pretensioned, independently of the pivot position of the ratchet  4 , into the position by spring force. 
     The ratchet  4  and the rocker arm  7  can be pretensioned in the indicated directions by two separate springs (not shown) or by a common spring  14  which is located on the swiveling axis of the ratchet  4  and/or of the rocker arm  7 , as shown in  FIGS. 2 and 3 . Against the force of these springs  14 , the traction means  6  can be wound up by the motor  5 . 
       FIG. 3 , in a representation which corresponds to  FIG. 2 , shows the motor vehicle lock  2  in the open state with the ratchet open and the rocker arm  7  open and with the traction means  6  wound. The pretensioning force acting on the ratchet  4  and/or the pretensioning force acting on the rocker arm  7  is or are preferably chosen and matched to the step-up or step-down ratio of the cable pull  11  as well as other mechanical influences such as the sluggishness of the motor  5 . With the motor  5  turned off, the traction means  6 , as a result of the indicated pretensioning force or forces, can be automatically unwound again from the driven shaft  8  so that the rocker arm  7  and/or the ratchet  4  is or are automatically reset again into the blocked position, or the position which allows the blocked position of the ratchet  4 . In this way, a very simple structure and very simple triggering of the motor vehicle lock  2  are enabled. 
       FIG. 2  shows the motor vehicle lock  2  in the locked and closed state. The latch  3  holding or securing a striker  15  or the like in the inlet slot  16  is shown schematically. The latch  3  in this state for its part is blocked or secured against opening by the engaged ratchet  4 . 
     The ratchet  4  can also be hook-shaped and can be used directly for securing the striker  15  or the like. The ratchet  4  can also have at least two hook sections, in order to imitate the conventional main catch position and the preliminary catch position of a conventional door lock with a latch. 
     Another embodiment of the motor vehicle lock  2  of the invention is explained below using  FIG. 4 . The only major differences from the first embodiment are explained below. Otherwise, the corresponding or comparable properties and advantages arise, the statements above applying accordingly. In the second embodiment, the traction means  6  is not guided around the deflection roller  12 , but via a speed transformation wheel  17  to the ratchet  4  or, as in the embodiment, to its rocker arm  7 . 
     The speed transformation wheel  17  is preferably made such that it reduces the winding-up motion of the motor  5  for the ratchet  4  or the rocker arm  7 . The speed transformation wheel  17  constitutes gearing for the traction means  6 . The speed transformation wheel  17  has a first motor-side wind-up area  18  and a second, driven-side wind-up area  19 . The wind-up areas  18 ,  19  are preferably located at least essentially coaxially and are securely connected to one another. In particular, the speed transformation wheel  17  is made in one piece, preferably injected from plastic. 
       FIG. 4  shows the motor vehicle lock  2  in the locked state. When the motor  5  is turned on, the traction means  6  is wound directly onto the motor shaft  8  and, in doing so, is unwound from the first wind-up area  18 , by which the speed transformation wheel  17  is turned. In this way, the drive-side part of the traction means  6  is wound onto the second wind-up area  19 , by which the desired actuation of the ratchet  4  or of the rocker arm  7  is caused. 
     The radius of the first wind-up area  18  is larger than the radius of the second wind-up area  19 , preferably at least by a factor of 2. In this way, a reduction of the motion of the traction means is achieved. 
     It is preferable for the effective winding radius of the first wind-up area  18  to vary. In the embodiment, the effective winding radius decreases when the speed transformation wheel  17  turns counterclockwise, yielding a worm-shaped or helical contour. This variation, especially the decrease or increase of the radius of the first wind-up area  18 , is conducive to lateral guidance of the traction means  6  so that the traction means  6  is wound up on the motor shaft  8  only in a helical line or in one layer. 
     Additionally or alternatively, by varying the radius of the first wind-up area  18  and/or of the second wind-up area  19  gear reduction can be varied. Proceeding from the locked state, having significant gear reduction (to overcome large holding or adhesion forces) to a rapid opening or unlocking state, having increasingly smaller gear reduction, the gear reduction can be varied. 
     In contrast to the deflection roller  12 , the speed transformation wheel  17 , on the housing  13  of the motor vehicle lock  2 , is pivotally supported. The axis of rotation  20  of the speed transformation wheel  17  runs preferably transversely, (e.g., perpendicularly) to the wind-up axle (the motor axle  8 ) and/or to the plane of motion or swiveling of the ratchet  4  or of the rocker arm  7 . 
     Resetting (i.e., an unwinding of the traction means  6 ) of the motor shaft  8  takes place preferably by means of the spring  14  or by other spring forces after the motor  5  is turned off. 
     It is unnecessary for the first part of the traction means  6  (which extends as far as the first wind-up area  18 ) and the second part of the traction means  6  (which extends from the second wind-up area  19  to the rocker arm  7 ) to be identical. The first and second part of the traction means  6  can therefore be formed of different pieces and/or different material and/or can have different dimensions, (e.g., due to their different traction load). 
     However, preferably the two parts of the traction means  6  are produced from a single piece of the traction means, especially the cable piece. The traction means  6  which comprises the indicated first and second part is preferably made therefore in one piece. Accordingly, the traction means  6  is guided on or in the speed transformation wheel  17  from the first wind-up area  18  to the second wind-up area  19 , as illustrated in  FIG. 4 . 
     The free end of the second part of the traction means  6  is preferably attached positively and/or by means of a lockable insert  21  to the ratchet  4  or, as in the embodiment, to the rocker arm  7 . In particular, the insert  21  is molded directly onto the traction means  6 . 
     The preferred manufacture is explained in detail as follows with respect to  FIG. 5 . Preferably, the traction means  6  is formed from a piece of material which is inserted directly into an injection mold so that, at the same time, the receiving part  9 , the speed transformation wheel  17  and the insert  21  are molded onto the traction means  6  and are produced in doing so. At the same, time a positive connection between the traction means  6  and the components (i.e., the receiving part  9 , the speed transformation wheel  17  and the insert  21 ) is produced. Optionally, the traction means  6  can be provided with a twist or the like, especially in the area of the speed transformation wheel  17  and/or in the area of its free ends, in order to ensure a reliable positive connection. 
     After their manufacture, the components are preferably first connected to one another via a connecting piece  22  such that the traction means  6  is, to some extent, held straight or taut. This facilitates support and handling until installation, since unwanted turning, tangling up, or binding of the traction means  6  is prevented. During installation then, the connecting piece  22  is released from the components. As a result, the receiving part  9 , the speed transformation wheel  17  and the insert  21 , and the traction means  6 , together with the components, can be installed properly in the motor vehicle lock  2 . 
     Since only one traction means piece is necessary, the production and installation cost is low since only the two ends of the traction means  6  need be cut off. Moreover, as  FIG. 4  makes especially clear, a largely free arrangement of the axes of rotation is possible and, thus, overall the arrangement of the components is optional. 
     An especially durable embodiment of the motor vehicle lock  2  is shown in  FIGS. 6 &amp; 7 . There is also the above described basic structure with the latch  3 , ratchet  4  and the motor  5  here. There is use of a flexible traction means  6  in the above indicated manner here. 
     In the embodiment of the invention shown in  FIGS. 6 and 7 , it is important that the connection formed between the motor  5  and the ratchet  4 , via the traction means  6  is a direct connection, without an interposed deflection means or the like. Thus, the traction means  6 , coming from the driven shaft  8  of the motor  5 , travels directly to the ratchet  4  and is attached to it. Proceeding from the locked state (shown in  FIG. 6 ), actuation of the motor  5  causes helical winding of the traction means  6  on the driven shaft  8  of the motor  5  until the unlocked or opened state, or an optionally provided overstroke position, of the ratchet  4  is reached. The ratchet  4  is also pretensioned by a spring  14  in the blocking direction. The spring  14 , in this embodiment, is a leg spring. 
     The ratchet  4  in all embodiments can be pivot around the ratchet axis  23 . In the embodiment shown in  FIGS. 6 &amp; 7 , the ratchet  4  is also equipped with an engagement element  24  which blocks the latch  3  in the locked state (shown in  FIG. 6 ). It is especially advantageous that the engagement element  24  is located comparatively near the ratchet axis  23 . In this way, the motor  5  can apply a comparatively small torque to the ratchet  4  to lift the latter. 
     It is advantageous if the engagement element  24  is located comparatively near the ratchet axis  23  and, at the same time, the point of application of the force of the traction means  6  is located on the ratchet  4  at a comparatively great distance from the ratchet axis  23 . As a result, the drive force to be transferred via the traction means  6  is low. 
     An especially compact arrangement is shown by the motor vehicle lock  2  shown in  FIG. 8 . The above described basic structure with the latch  3 , ratchet  4  and motor  5  (not shown) is also implemented. Furthermore, there is also a flexible traction means  6  for opening the ratchet  4 . The ratchet  4  can be pivoted around axis  23  and can be pretensioned by means of a spring (not shown) in the blocking direction (to the right in  FIG. 8 ). The motor vehicle lock which is shown in  FIG. 8  is in the locked state. 
     In the embodiment shown in  FIG. 8 , the ratchet  4  has an essentially cylindrical segment  25 . The cylindrical segment  25  can be aligned centrally or eccentrically to the ratchet axis  23 . The cylindrical segment  25  is aligned centrally to the ratchet axis  23 . Note that the traction means  6  is attached to the jacket surface of the cylindrical segment  24  for connection of the motor  5  to the ratchet  4  and that it is deflected by the jacket surface. The arrangement is made such that pivoting of the ratchet  4  can be effected by the motor  5  via the traction means  6 . 
     With respect to actuation of the ratchet  4 , there need not be a lever or the like provided on the ratchet for connection of the traction means  6 . The task of this lever is performed by the cylindrical segment  25  of the ratchet  4 . In the central alignment of the cylindrical segment  25  to the ratchet axis  23 , a constant drive force which has been transmitted via the traction means  6  causes a constant drive moment on the ratchet  4  over the entire range of movement of the ratchet  4 . Conversely, the eccentric alignment of the cylindrical segment  25  to the ratchet axis  23  causes a speed transformation which changes with the motion of the ratchet  4 . This can be advantageous, as described above. It should be pointed out that this ratchet  4  also has an engagement element  24  which is located comparatively near the ratchet axis  23 . As described above, this leads to a comparatively small drive force required to be applied for actuation of the ratchet  4 . 
     For the embodiment of the cylindrical segment  25  of the ratchet  4 , a series of possibilities is conceivable. For example, the section can be narrow, just wide enough to ensure the corresponding winding or unwinding of the traction means  6  onto or off of the ratchet  4 . But the cylindrical segment  25  can also extend essentially over the entire width of the ratchet  4 . 
     In the two embodiments as shown in  FIGS. 6 ,  7  and  FIG. 8 , respectively, the engagement section  24  projects out of the ratchet  4  (in  FIGS. 6 to 8  out of the plane of the drawings). In this way, engagement between the engagement element  24  and the latch  3  is ensured. 
     Finally, the attachment of the traction means  6  to the housing  13 , to the driven shaft  8  and to the receiving part  9  or to the ratchet  4  or the rocker arm  7  acquires special importance. Some possibilities in this respect have already been further explained above. In summary it should be pointed out that here all conceivable types of attachment can be used. Examples of this are suspension, binding, looping or clamping, and laser welding, cementing, extrusion coating or casting-in.