Abstract:
The invention relates to a camber control suspension of a vehicle that can form a stable camber angle even at the time when the vehicle rolls as well as when it bumps and rebounds, including a camber control rack and camber control links with a function of controlling camber of wheels by stopping or moving according to the vertical motion of both wheels, thereby achieving the most stable grounding state of tires at all times to sufficiently enhance the grounding force of tires at any running state of the vehicle.

Description:
BACKGROUND OF THE INVENTION  
         [0001]    1. Field of the Invention  
           [0002]    The present invention relates to a suspension of a vehicle, and more particularly to a suspension of a vehicle that can form a stable camber angle even at the time when the vehicle bumps and rebounds as well as when it rolls.  
           [0003]    2. Brief Description of the Prior Art  
           [0004]    In general, a camber indicates an angle that forms between a center line of wheels and a vertical line about road surface. The camber prevents the bottom part of front wheels from being stretched by weight and also the wheels from being loosened out while a vehicle is running. Especially, it also plays a role to facilitate an easy manipulation of a steering wheel along with an inclination angle of kingpin.  
           [0005]    However, such camber does not always keep its angle constant while the vehicle is running, but changes its angle according to the running state of the vehicle, mainly depending on types of selected suspensions. The different types of changes will be described in accordance with a few types of suspensions.  
           [0006]    First of all, FIG. 1 illustrates a conventional trailing arm type or a double wishbone type of a suspension that has the similar length of upper and lower arms. As shown in FIG. 1, it is possible to design a camber of wheels that can make the vertical motions with almost no change in the camber angle, close to 0 degree, even when the vehicle bumps and rebounds. However, there will be a change in the camber angle as great as the vehicle rolls as shown in FIG. 2, thereby deteriorating grounding capability of a tire tread to weaken cornering force.  
           [0007]    Next, a conventional swing arm type or a double wishbone type of a suspension which has the different length of upper and lower arms, can be designed to keep changes in the camber of wheels  102  close to 0 when the vehicle rolls as shown in FIG. 4. Therefore, it is possible to sufficiently secure the grounding capability of the wheels tread onto the road surface. On the other hand, when the vehicle bumps and rebounds, there will be a change in the camber to deteriorate a straight running stability of the vehicle.  
           [0008]    As described above, there is a problem in the conventional structures of suspensions in that the conventional suspension can optimally facilitate only either when it bumps and rebounds or when it rolls, so that it has had no alternative but bear its structural problem of deteriorating one of the aforementioned motions of the vehicle because the suspension has been designed for a vehicle in simple consideration of either when the vehicle runs straight or when it turns around.  
         SUMMARY OF THE INVENTION  
         [0009]    It is an object of the present invention to solve the aforementioned problem and provide a camber control suspension of a vehicle that can make its optimum geometry at a straight running or turning state of the vehicle, thereby not only achieving a stable grounding state of tires when the vehicle is straight running with bump/rebound motions, but also forming sufficient grounding force of tires for strong cornering force when the vehicle is turning with a rolling motion.  
           [0010]    In order to accomplish the aforementioned object of the present invention, there is provided a camber control suspension comprising:  
           [0011]    two roll detecting links respectively connected to the front part of a wheel rotational center at a knuckle of a left wheel and to the rear part of the wheel rotational center at a knuckle of a right wheel and forming a shape of letter L by being bent at a position where the links cross with a vertical line passing through the wheel rotational center;  
           [0012]    a rotary support bracket supporting against vehicle body and guiding rotations of the two roll detecting links;  
           [0013]    a differential gear unit having bevel gears installed at each end of the two roll detecting links for both side gears;  
           [0014]    a worm gear formed at a differential gear case of the differential gear unit;  
           [0015]    a camber control rack formed with a gear meshed to the worm gear and horizontally installed with a vehicle axle to make a horizontal linear motion;  
           [0016]    camber control links connecting both sides of the camber control rack to both wheel knuckles; and  
           [0017]    lower links supporting a lower side of the wheel rotational center of the knuckles against a frame. 
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0018]    Objects and aspects of the invention will become apparent from the following description of preferred embodiments with reference to the accompanying drawings in which:  
         [0019]    [0019]FIG. 1 illustrates bump/rebound motions of a general trailing arm type or a double wishbone type of a suspension that has the similar length of upper and lower arms;  
         [0020]    [0020]FIG. 2 illustrates a rolling motion of a general trailing arm type or a double wishbone type of a suspension that has the similar length of upper and lower arms;  
         [0021]    [0021]FIG. 3 illustrates a rolling motion of a general swing arm type or a double wishbone type of a suspension that has different length of upper and lower arms;  
         [0022]    [0022]FIG. 4 illustrates a rolling motion of a general swing arm type or a double wishbone type of a suspension that has the similar length of upper and lower arms;  
         [0023]    [0023]FIG. 5 is a plan view for illustrating the structure of a camber control suspension in accordance with the present invention;  
         [0024]    [0024]FIG. 6 is a front view of FIG. 5;  
         [0025]    [0025]FIG. 7 is an explanatory view for illustrating the operational state of a differential gear unit at the time of bump/rebound of a suspension in accordance with the present invention;  
         [0026]    [0026]FIG. 8 is an explanatory view for illustrating the operational state of a differential gear unit at the time of rolling of a suspension in accordance with the present invention; and  
         [0027]    [0027]FIG. 9 illustrates an operational view of a suspension in accordance with the present invention at the time of rolling. 
     
    
     DETAILED DESCRIPTION OF THE INVENTION  
       [0028]    Hereinafter, a preferred embodiment of the present invention will be described in detail with reference to accompanying drawings.  
         [0029]    [0029]FIGS. 5 and 6 illustrate a camber control suspension in accordance with an embodiment of the present invention, comprising: two roll detecting links  3 L,  3 R respectively connected to the front part of a wheel rotational center at a knuckle  1  L of a left wheel and to the rear part of the wheel rotational center at a knuckle  1 R of the right wheel and forming a shape of letter L by being bent at a position where the links cross with a vertical line passing through the wheel rotational center C; a differential gear unit  7  having bevel gears installed at each end of the two roll detecting links for both side gears  5 L,  5 R; a worm gear  11  formed at a differential gear case  9  of the differential gear unit  7 ; a camber control rack  13  formed with a gear meshed to the worm gear  11  and horizontally installed with a vehicle axle to make a horizontal linear motion; camber control links  15 L,  15 R connecting both sides of the camber control rack  13  to both wheel knuckles  1 L,  1 R; and lower links  17 L,  17 R supporting a lower side of the wheel rotational center C of the knuckles  1 L,  1 R against a frame.  
         [0030]    For reference, the camber control rack  13  and camber control rings  15 L,  15 R shown in FIG. 6 are omitted in FIG. 5. Besides, lateral links  19  and tow links  20  can be installed as shown in FIG. 5.  
         [0031]    The two roll detecting links  3 L,  3 R are connected to both knuckles  1 L,  1 R with ball joint links  21  having ball joints at both ends thereof. The ball joint links  21  are vertically installed to transmit the vertical motions of the wheels including the knuckles  1 L,  1 R to the roll detecting links  3 L,  3 R. The roll detecting links  3 L,  3 R are supported against the vehicle body through rotary supporting brackets  23  for rotation according to the vertical motion of the wheels transmitted through the knuckles  3 L,  3 R and ball joint links  21 .  
         [0032]    The differential gear unit  7  has a very similar structure to the conventional differential gear unit. As shown in FIGS. 7 and 8, the bevel gears installed at both ends of the roll detecting links  3 L,  3 R are regarded as side gears  5 L,  5 R. A pinion gears  25  are meshed with the two side gears  5 L,  5 R and a differential gear case  9  separated from the side gears  5 L,  5 R to support a rotational axle of the pinion gear  25  and rotatably installed at the external side of side gears  5 L,  5 R. There is only one difference from the conventional differential gear in that there is no ring gear assembled in the differential gear case  9  to get rotational force from a propeller shaft.  
         [0033]    Besides, the worm gear  11  is installed at the differential gear case  9 , and the camber control rack  13  is meshed thereto, so that the camber control rack  13  can be linearly moved to the direction in parallel to the vehicle axle by rotation of the worm gear  11 . At this time, the worm gear  11  is set for the camber control rack  13  to be linearly moved to the wheel to be rebounded. The camber control links  15 L,  15 R are connected to transmit the linear motion of the camber control rack  13  to the upper side of the wheel rotational center C of the both wheel knuckles  1 L,  1 R. The low links  17 L,  17 R are constructed to support the lower side of the knuckles  1 L,  1 R against the frame of the vehicle body with the similar length of the camber control links  15 L,  15 R.  
         [0034]    Operations of the present invention thus constructed will be described below.  
         [0035]    When both wheels vertically move simultaneously in straight driving or bump/rebound motions of a vehicle, the wheels move similarly to those in the double wishbone type suspension having similar length of arms as shown in FIG. 1 because the length of the camber control links  15 L,  15 R and that of the lower links  17 L,  17 R are similar. At this time, the vertical motion of the knuckles  1 L,  1 R rotates the roll detecting links  3 L,  3 R through the ball joint links  21 , and the roll detecting links  3 L,  3 R are rotated in opposite directions as shown in FIG. 7. Thus, the side gears  5 L,  5 R connected to the roll detecting links  3 L,  3 R are rotated in the opposite directions to further rotate the pinion  25  of the differential gear unit  7 . In other words, the pinion  25  is simply rotated, but the differential gear case  9  providing a rotational axle to the pinion  25  is not rotated.  
         [0036]    Therefore, the camber control rack  13  meshed to the worm gear  11  installed in the differential gear case  9  maintains its fixed state without any movement. The camber control links  15 L,  15 R connected to the camber control rack  13  are operated with the lower links  17 L,  17 R with the special characteristics of the conventional trailing arm type or double wishbone type of a suspension having the similar length of arms. As a result, it is possible that a vehicle can secure a smooth straight running capability with sufficient grounding force of tires with almost no change in the camber when wheels perform bump/rebound motions.  
         [0037]    Next, the vertical motion of the wheels becomes opposite when a vehicle rolls or turns around. The knuckles  1 L,  1 R move to the opposite directions to carry both of the ball joint links  21  to opposite directions, which rotates the two roll detecting links  3 L,  3 R to an identical direction. At this time, two side gears  5 L,  5 R are under a unidirectional rotational force of the roll detecting links  3 L,  3 R. As the two side gears  5 L,  5 R do not rotate a pinion  25 , but revolve the pinion  25  at its fixed state on the circumference. As a result, the differential gear case  9  can be rotated.  
         [0038]    If a description about the operations of the present invention will be made with reference to FIG. 9, rotations of the differential gear case  9  makes it possible for the camber control rack  13  to make a linear motion owing to worm gear  11 . The linear motion is performed to a direction of a wheel, to which the camber control rack  13  is rebound. In other words, in the drawing the linear motion of the camber control rack  13  is made to the left wheel. While the camber control link  15 L pushes the upper part of the knuckle  1  L of the left wheel to outside of vehicle body to thereby result in a change into a positive value of a camber, the upper part of the right knuckle  1 R to be bumped is pulled by the camber control link  15 R to thereby result in a change into a negative value of a camber. However, if the rolling motion of the vehicle body is considered, it is possible for a change in the camber against the road surface to be kept close to 0.  
         [0039]    If the vehicle is turning to the reverse direction or rolling, the camber control rack  13  and two camber control links  15 L,  15 R are moved in the opposite directions and a change in the camber against road surface is kept close to 0, thereby making it possible to continuously secure good grounding force.  
         [0040]    As described above, not only when a vehicle runs straight or turns around, but also when a vehicle rolls or bumps/rebounds, the camber control rack and camber control links can adjust a camber of wheels by stopping or moving according to vertical motion of both wheels to thereby keep the best grounding state of tires against the road surface, thereby making it possible to secure the good capability of grounding tires for safe drive at any running state of a vehicle.  
         [0041]    In addition, the present invention has a similar structure to a double wishbone or multi-link type suspension, so that it is advantageous in securing other functions of the conventional double wishbone or multi-link type suspension in addition to the camber controlling function described above.