Abstract:
A trailing arm is provided that comprises: a first coupling member connectable with a vehicle body; a second coupling member connectable with a wheel assembly; and a plurality of connecting beams for connecting the first and second coupling members together. Each of the connecting arms are angled with respect to a longitudinal direction of the trailing arm such that the connecting arms cross paths, or cooperatively form an X-shape, as they diagonally connect the first and second coupling members together.

Description:
FIELD OF THE INVENTION  
         [0001]    Generally, the present invention relates to a suspension system. More specifically, the present invention relates to a trailing arm for a rear suspension system of a vehicle in which lateral force and axial force can be absorbed.  
         BACKGROUND OF THE INVENTION  
         [0002]    Generally, a rear suspension system of a vehicle includes a trailing arm for connecting the vehicle body with the rear wheel assembly. Typically, a trailing arm is connected to a knuckle through bolts at one end of the trailing arm. The other end of the trailing arm is generally connected to a vehicle body through a bushing. Generally, a linking member of the trailing arm must endure a great deal of stress, and the rear suspension system is designed such that deformation occurs only in the bushing or spring where the trailing arm attaches to the vehicle body.  
           [0003]    However, in some designs, deformation of the suspension system occurs in two directions. That is, the trailing arm can rotate by a force applied in the vertical direction or the trailing arm can flex from a force applied in a direction perpendicular to its longitudinal axis. Therefore, a lateral deformation of the trailing arm occurs simultaneously with deformation of the bushing connecting the trailing arm to the vehicle body. Both deformations have an effect on the suspension characteristics.  
           [0004]    For good suspension characteristics, the trailing arm must be sufficiently deflected during vehicle displacement in the vertical direction, yet structurally sufficient to withstand permanent deformation. If the trailing arm is too flexible, force will be transmitted to the bushing in a lateral direction which has a negative result of excessive wear on the bushing.  
           [0005]    Furthermore, typical trailing arms cannot absorb axial force generated along the longitudinal direction of the trailing arm such that impacts to the wheel that generate force applied along that direction are transferred to the occupants of the vehicle and create an uncomfortable ride.  
         SUMMARY OF THE INVENTION  
         [0006]    In a preferred embodiment of the present invention, a trailing arm includes a first coupling member connected to a second connecting member by a plurality of connecting beams. In use, the first coupling member is connectable with a vehicle body, the second coupling member is connectable with a wheel assembly, and the plurality of connecting beams connect the first and second coupling members together.  
           [0007]    It is preferable that the plurality of connecting beams comprise a set of first connecting beams and a second connecting beam that are not parallel to each other with respect to the longitudinal axis of the trailing arm. In use, the set of first connecting beams and second connecting beam cooperatively form an X-shape, in a cross sectional view, as they diagonally connect the first and second coupling members together.  
           [0008]    It is also preferable that the first coupling member is provided with a hollow portion perforated therethrough. 
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0009]    The accompanying drawings, which are incorporated in and constitute a part of the specification, illustrate an embodiment of the invention, and, together with the description, serve to explain the principles of the invention, where:  
         [0010]    [0010]FIG. 1 schematically shows the trailing arm according to a preferred embodiment of the present invention;  
         [0011]    [0011]FIG. 2 is a diagram showing the trailing arm of FIG. 1 deformed by a lateral force; and  
         [0012]    [0012]FIG. 3 is a diagram showing the trailing arm of FIG. 1 deformed by an axial force. 
     
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS  
       [0013]    Hereinafter, a preferred embodiment of the present invention will be described in detail with reference to the accompanying drawings.  
         [0014]    As shown in FIG. 1, a trailing arm  100 , for use in a rear suspension system, according to an embodiment of the present invention, includes a first coupling member  10  for coupling it to a vehicle body  70 , a second coupling member  20  for coupling it to a wheel assembly  90 , a plurality of first connecting beams  30 , and a second connecting beam  40 .  
         [0015]    It is preferable that the first coupling member  10  is provided with a cylindrical hollow portion  12  for the connection to the vehicle body  70 , through a coupling device, such as for example a bushing or a bolt (not shown). The second coupling member  20  is provided for coupling the trailing arm  100  to the wheel assembly  90 . It is preferable that the second coupling member  20  is coupled to a knuckle (not shown) of the wheel assembly  90  through bolts or the like.  
         [0016]    The plurality of first connecting beams  30  are in substantial alignment with each other. However, the plurality of first connecting beams  30  are not parallel to the longitudinal axis of the trailing arm such that the plurality of first connecting beams  30  diagonally interconnect the first coupling member  10  with the second coupling member  20 . The longitudinal direction of the trailing arm is substantially similar to the longitudinal axis of the vehicle. The angle of the plurality of first connecting beams  30  can preferably be determined, with respect to the longitudinal axis of the trailing arm, on the basis of the length of the plurality of first connecting beams  30 , the thickness of the plurality of the first connecting beams  30 , and the size of the wheel to which the second coupling member  20  is to be attached.  
         [0017]    The second connecting beam  40  is not parallel to the longitudinal axis of the trailing arm such that the second connecting beam  40  diagonally interconnects the first coupling member  10  with the second coupling member  20 . The angle of the second connecting beam  40  can preferably be determined, with respect to the longitudinal axis of the trailing arm, on the basis of the length of the second connecting beam  40 , the thickness of the second connecting beam  40 , and the size of the wheel to which the second coupling member  20  is to be attached.  
         [0018]    The angle of the second connecting beam  40  is directed toward the plurality of first connecting beams  30 , and the angle of the plurality of first connecting beams  40  is directed toward the second connecting beam  40  such that the path of the plurality of first connecting beams  30  and the path of the second connecting beam  40  cross somewhere along the path between the first coupling member  10  and the second coupling member  20 . Thereby the plurality of first connecting beams  30  and the second connecting beam  40  cooperatively form an “X” shape if viewed in cross section.  
         [0019]    In use, under this configuration, the trailing arm  100  can absorb a moment of inertia with respect to the Z-axis (hereinafter referred to as a vertical force), a force in a lateral Y-axis direction, or in other words, a force applied perpendicular to the longitudinal axis of the trailing arm (hereinafter referred to as a lateral force), and a force in a longitudinal X-axis direction, or in other words, a force directed along the longitudinal axis of the trailing arm (hereinafter referred to as an axial force).  
         [0020]    It is to be appreciated that although the trailing arm  100  of FIG. 1 is shown with two first connecting beams  30  and one second connecting beam  40 , the number of first connecting beams and second connecting beam(s) can preferably be changed according to expected magnitudes of the lateral and the axial forces, and the like.  
         [0021]    With reference to FIGS. 2 and 3, operations of the trailing arm  100  under the lateral force and the axial force will respectively be explained.  
         [0022]    In FIGS. 2 and 3, solid lines shows a state before deformation, and dotted lines show a state after deformation.  
         [0023]    As shown in FIG. 2, if a lateral force is applied to the trailing arm  100 , the first connecting beams  30  and second connecting beam  40  are flexed in the direction of the lateral force so that the trailing arm  100  is deformed along the Y-axis direction (refer to FIG. 1 for axis directions). In use, during this deformation, the lateral force is substantially absorbed in the first connecting beams  30  and second connecting beam  40  of the trailing arm  100 .  
         [0024]    As shown in FIG. 3, if an axial force is applied to the trailing arm  100 , the first connecting beams  30  and second connecting beam  40  are flexed so that the trailing arm  100  is deformed along the X-axis direction (refer to FIG. 1 for axis directions). In use, during this deformation, the axial force is substantially absorbed in the trailing arm  100 . Therefore, axial impacts on the wheel assembly can be substantially absorbed.  
         [0025]    Referring now to FIG. 2, a length H of the trailing arm  100  is larger than a width W of the trailing arm  100 , and it is preferable that axial integrity of the trailing arm  100  is set to be greater than a lateral integrity of the trailing arm  100  such that both desired suspension characteristics and a desired structural integrity of the trailing arm  100  are satisfied.  
         [0026]    Consequently, the trailing arm  100  according to the present invention can be designed to have any desired structural integrity with respect to an impact force originating from any of the X, Y, or Z axis directions.  
         [0027]    Although a preferred embodiment of the present invention has been described in detail hereinabove, it should be clearly understood that many variations and/or modifications of the basic inventive concepts herein taught which may appear to those skilled in the present art will still fall within the sprit and scope of the present invention, as defined in the appended claims.