Abstract:
A gearshift device for a change-speed gearbox of a motor vehicle, includes, but is not limited to a gearshift lever guided movably between positions corresponding to different gears, on which a locking member is displaceable between a locking position in a first degree of freedom in which it blocks any movement of the gearshift lever from a forward gear position into a reverse gear position, and a release position in a first degree of freedom in which it allows movement from the forward gear position into the reverse gear position. The locking member on the gearshift lever is movable in a second degree of freedom between a normal position in which movement between release position and locking position is possible and an alignment position in which it fixes the gearshift lever free from play.

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
       [0001]    This application claims priority to German Patent Application No. 102008030233.3, filed Jun. 25, 2008, which is incorporated herein by reference in its entirety. 
       TECHNICAL FIELD 
       [0002]    The present invention relates to a gearshift device for a change-speed gearbox of motor vehicles comprising a gearshift lever and a so-called reverse gear block. 
       BACKGROUND 
       [0003]    The gearshift lever located in the passenger compartment of a motor vehicle after installing the gearshift device is guided movably between positions which correspond to various gears of the change-speed gearbox. A coupling device such as a linkage or cable controls extends between the gearshift device and the change-speed gearbox in order to couple the position of gearshift forks of the change-speed gearbox to the position of the gearshift device. In order to ensure that one of the predefined positions of the gearshift lever actually corresponds exactly to a configuration of the gearshift forks in which a desired gear is engaged, an alignment of the coupling device is required. In order to be able to perform such an alignment exactly, it is desirable to be able to immobilize the gearshift lever in at least one position free from play. 
         [0004]    It is known to implement a reverse gear block by providing a longitudinally displaceable hook on the gearshift lever, which, when the gearshift lever approaches its position corresponding to the reverse gear, impacts against a barrier in order to prevent any accidental engagement of reverse gear, which can overcome the barrier by displacement along the shaft of the gearshift lever and which prevents accidental disengagement of reverse gear by engaging behind the barrier. In order that the engagement of the gear behind the barrier takes place reliably, it must retain some play. Consequently, the gearshift lever is not completely immovable in the reverse gear position. The conventional locking of the gearshift lever in the reverse gear position is therefore not suitable for sufficiently immobilizing the gearshift lever for the purpose of alignment. 
         [0005]    At least one object of the present invention is to provide a gearshift device which allows play-free immobilization of the gearshift lever for the alignment but at the same time allows the necessary play in the function mode. In addition, other objects, desirable features and characteristics will become apparent from the subsequent summary and detailed description, and the appended claims, taken in conjunction with the accompanying drawings and this background. 
       SUMMARY 
       [0006]    The at least one object, other objects, desirable features and characteristics, are achieved whereby in a gearshift device for a change-speed gearbox of a motor vehicle having a gearshift lever guided movably between positions corresponding to different gears. A locking member on the gearshift lever is displaceable in a first degree of freedom, the locking member on the gearshift lever is movable in a first degree of freedom between a normal position in which it allows a shifting movement of the gearshift lever and an alignment position in which it fixes the gearshift lever free from play. 
         [0007]    The locking member is preferably additionally movable in a second degree of freedom between a locking position in which it blocks a shifting movement of the gearshift lever from a forward gear position into a reverse gear position, and a release position in which it allows movement from the forward gear position into the reverse gear position. 
         [0008]    The locking member is preferably a sleeve surrounding a shaft of the gearshift lever. The first degree of freedom of the locking member is preferably a rotation about the shaft, the second degree of freedom is a movement in the longitudinal direction of the shaft. 
         [0009]    In order to achieve freedom of play in the alignment position and to retain some play in the normal position, the locking member and shaft each have a contoured side surface, and in the normal position the contours of the contoured side surface intermesh in a complementary manner, whereas in the alignment position they do not do this. 
         [0010]    If the first degree of freedom is a rotation as mentioned above, a changeover between engagement and nonengagement of the contours can easily be achieved by the contoured side surfaces of the locking member and the shaft not lying opposite to one another in the alignment position. Instead, in the alignment position projecting contours of the locking member or the shaft preferably contact a flat side surface of the shaft or the locking member. 
         [0011]    In order to be able to transfer the sleeve forming the locking member from the normal position into the alignment position without needing to detach this from the shaft, the shaft preferably comprises a section guiding the sleeve in a rotationally fixed manner, and a section allowing a rotation of the sleeve about the shaft when the sleeve is located at the height of said shaft. In the release position, however, the sleeve is preferably located on the guiding section. 
         [0012]    A spring can be provided to act upon the sleeve along the shaft from the section allowing rotation in the direction of the guiding section. This ensures that the sleeve cannot accidentally arrive at the section allowing rotation. 
         [0013]    In order to unlock the locking member when using the locking member as a reverse gear block and be able to switch between forward and reverse gear, a control element coupled to the sleeve is preferably attached to a handle of the gearshift lever. 
         [0014]    The freedom of movement of the control element is preferably not sufficiently large to entrain the sleeve into the section allowing rotation. The driver cannot therefore accidentally change over between the alignment and the normal position; if, however, the locking member is exposed during assembly of the vehicle or during a repair, such a changeover can be performed conveniently by pulling the locking member on the section allowing rotation and turning it there. 
         [0015]    As further security against an undesirable transition of the locking member onto the section allowing rotation, a latching device can be provided, which can be engaged by a movement of the locking member from the section allowing rotation to the guiding section. Such a latching device can preferably only be engaged when the locking member is located in the alignment position. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0016]    The present invention will hereinafter be described in conjunction with the following drawing figures, wherein like numerals denote like elements, and: 
           [0017]      FIG. 1  shows a section through a gearshift device according to the invention in the longitudinal direction of its gearshift lever; 
           [0018]      FIG. 2  shows a section transverse to the gearshift lever along the plane designated by II-II in  FIG. 1  which shows the locking member in the alignment position; 
           [0019]      FIG. 3  shows a section similar to  FIG. 2  with the locking member in the normal position; 
           [0020]      FIG. 4  shows a section similar to  FIG. 1  with the locking member in the normal position; and 
           [0021]      FIG. 5  shows a partial section of the gearshift device along the longitudinal axis of the gearshift lever in a plane perpendicular to the plane of intersection of  FIG. 1 . 
       
    
    
     DETAILED DESCRIPTION 
       [0022]    The following detailed description is merely exemplary in nature and is not intended to limit application and uses. Furthermore, there is no intention to be bound by any theory presented in the preceding background and summary or the following detailed description. 
         [0023]    The sectional view in  FIG. 1  shows a gearshift lever  1 , which is mounted in a holder of a motor vehicle fixed to the bodywork, not shown in detail, so that it is pivotable by means of a ball joint  2  or another joint in two degrees of freedom, hereafter designated as selecting or shifting degree of freedom. The gearshift lever  1  has an elongate shaft  3 , which has a handle  4  at its end facing away from the ball joint  2 . The shaft  3  is substantially composed of a cylindrical tube  5  extending between the ball joint  2  and the handle  4  and a guiding body  6  of approximately square cross section, which encloses a lower section of the tube  5  adjacent to the ball joint  2 . 
         [0024]    A flexible bellows  9  surrounds an upper section  7  of the shaft  3  protruding from the guiding body  6  and is fastened to the guiding body by means of a peripheral collar  8 . The shaft extends through an opening in a transmission tunnel not shown and the outer edge of the bellows  9  is connected to the edge of the opening to close off the interior of the transmission tunnel toward the passenger compartment. 
         [0025]    A helical spring  10  is supported on the collar  8 , which helical spring acts upon a locking sleeve  11  displaceable on the shaft  3  against the guiding body  6  so that the guiding body  6  engages in an internal cavity of the locking sleeve  11 . 
         [0026]    A pull rod  12  extends in the hollow interior of the shaft  3 . A hook  13  angled at one end of the pull rod  12  engages through a slot of the tube  5  into the interior of the locking sleeve  11 . An upper end of the pull rod  12  is connected to an actuating ring  14 , which is mounted displaceably below the handle  4  on the shaft  3 . 
         [0027]    The locking sleeve  11  has two hooks  15  on one side, which, in the configuration shown, engage with their cylindrical tip  31  parallel to the shaft  3  in a manner free from play in a hole on an oblique surface facing away from the shaft  3  of a fixed web  17  in relation to the transmission tunnel. A hook  35  on the opposite side of the locking sleeve  11  does not engage. 
         [0028]    The web  17  is here part of a guiding link in which shift and select gates orthogonal to one another are cut out in a manner known per se to guide the movement of the shaft  3  extending through these gates in the shifting or selecting degree of freedom. The select gate extends in the plane of intersection of  FIG. 1 . In the configuration shown the gearshift lever  1  is located at the end of the select gate  18 , from which the shift gate of the reverse gear branches off. Due to the engagement of the two tips  31  in the holes of the web  17 , the locking sleeve  11  is fixed free from play on the shift link in the shifting degree of freedom and in the selecting degree of freedom. 
         [0029]      FIG. 2  shows a section through the locking sleeve  11  and the shaft  3  in the configuration of  FIG. 1  along the plane designated by II-II in  FIG. 1 . The guiding body  6  has a substantially rectangular cross-section with ribs  22 ,  23  projecting on two opposite side surfaces  20 ,  21 . The ribs  22  on the side surface  20  each have a flat front face parallel to the side surface  20 , which each has a flat rib  24  on an inner side of the locking sleeve  11  opposite to a part of its width. The ribs  23  have a stepped front surface beyond over the side surface  21 . The respectively further projecting sections  25  abut against the inner surface of the locking sleeve  11 . 
         [0030]    The other two opposite side surfaces  27 ,  28  of the guiding body  6  have a different length to the side surfaces  20 ,  21 . The side surface  27  is provided with flat ribs  29  while the other side surface  28  is flat. The flat side surface  28  contacts ribs  30  of an opposite inner surface of the locking sleeve  11  while the ribs  29  contact a flat inner surface of the locking sleeve  11 . The locking sleeve  11  thus rests free from play on the guiding body  6 . In this way, the gearshift lever  1  is fixed free from play in its two degrees of freedom and a coupling device, not shown, which is known per se, and connects the gearshift lever  1  to the gearshift forks of the change-speed gearbox can be aligned without the gearshift lever  1  yielding to the forces which occur during alignment. 
         [0031]    After the alignment, the fixing of the gearshift lever  1  is released by grasping the locking sleeve  11  by the hand and lifting it sufficiently far against the restoring force of the helical spring  10  that the guiding body  6  no longer engages in the locking sleeve  11 . In this position, the locking sleeve  11  is freely rotatable about the shaft  3 . If this is turned through approximately 180° and then released, it slides onto the guiding body  6  again in the orientation shown in cross section in  FIG. 3  and shown in longitudinal section in  FIG. 4 . The flat side surface  28  and the side surface  20  with unstepped ribs  22  now lie opposite flat inner surfaces of the locking sleeve  11 , the ribs  24  lie opposite the sections  26 , and the ribs  30  each engage between the ribs  29 . The engagement of the guiding body  6  in the locking sleeve  11  is thus play-retaining transversely to the shaft  3  in two directions, in the shifting and in the selecting degree of freedom, so that there is no risk of the locking sleeve  11  jamming on the guiding body  6 . 
         [0032]    The holes in the web  17  which can be identified in the plan view in  FIG. 3  are now empty; the hooks  15  do not engage on the side of the locking sleeve  11  facing away from the web  17 . Instead, a short rib  36  is formed on the web  17 . 
         [0033]    When the gearshift lever is moved from the alignment position at the end of the select gate  18  into the shift gate of the reverse gear running parallel to the web  17 , the hook  35  slides along on the web  17  and ultimately engage behind the rib  36 . If, on the other hand, it is moved into the select gate, the hook  35  jumps down from the web  17 . A movement of the gearshift lever  1  back to the end of the select gate is only possible if the locking sleeve  11  is raised by pulling up the actuating ring  14 . 
         [0034]    As the preceding description shows, the locking sleeve  11  provides a double function in this gearshift device, on the one hand, in the orientation in  FIG. 2  it serves as a play-free fixing of the gearshift lever  1  which allows alignment of the coupling device and on the other hand, in the orientation in  FIG. 3 , it functions as a reverse gear block which retains play with respect to the guiding body  6  in order to be reliably movable along the shaft  3  and reliably return to the locking position when the actuating ring  14  is released. 
         [0035]    The restoring force of the helical spring  10  can be sufficient to reliably prevent the case that, when the actuating ring  14  is pulled up and the locking sleeve  11  is in its release position, the locking sleeve  11  is moved so far upward that it loses its engagement with the guiding body  6  and becomes rotatable. In order that pulling up the actuating ring  14  is not made unnecessarily difficult for the driver, it can however be desirable to make the restoring force of the helical spring  10  small. 
         [0036]      FIG. 5  shows a partial section through the gearshift device  1  along the plane designated by V-V in  FIG. 1 . Formed inside the guiding body  6  is a resilient tongue  32  extending in the longitudinal direction of the shaft  3 , which has a beveled latching projection  33  at its tips. When the locking sleeve  11  is located in the orientation in  FIG. 2 , the tip of the latching projection  33  dips into a recess  34  on an inner surface of the locking sleeve  11 . The locking sleeve  11  cannot therefore slip away from the guiding body  6 . This is particularly advantageous when the shaft  3  with tube  5 , guiding body  6 , and ball joint  2  but without the handle  4  forms a preassembled structural unit, which is to be mounted in the vehicle in its entirety since loss of the locking sleeve  11  before attachment of the handle  4  can thus be prevented. 
         [0037]    Nevertheless, the locking sleeve  11  can be pulled away from the guiding body  6  after alignment with no difficulties since a large part of the tongue  32  is exposed below the locking sleeve  11  and can be pressed in by hand to cancel the latching and pull the locking sleeve upwards from the guiding body  6 . Finally, the locking sleeve  11  can be turned through approximately 180° and placed on the guiding body  6  again to produce the normal position. 
         [0038]    In the normal position, an internal surface of the locking sleeve  11 , having no recess  34 , is located opposite the latching projection  33 . In the normal position, therefore latching is not possible but also is not necessary. 
         [0039]    While at least one exemplary embodiment has been presented in the foregoing summary and detailed description, it should be appreciated that a vast number of variations exist. It should also be appreciated that the exemplary embodiment or exemplary embodiments are only examples, and are not intended to limit the scope, applicability, or configuration in any way. Rather, the foregoing summary and detailed description will provide those skilled in the art with a convenient road map for implementing an exemplary embodiment, it being understood that various changes may be made in the function and arrangement of elements described in an exemplary embodiment without departing from the scope as set forth in the appended claims and their legal equivalents.