Abstract:
An inverted tricycle, which includes: deflecting and steering mechanism, rear frame, driving wheel, two front wheels, said deflecting and steering mechanism configured on the front end of said rear frame, said two front wheels and said deflecting and steering mechanism connected to each other, and symmetrically configured on the left and right sides of the front end of said rear frame, with the rear frame as the axis of symmetry, said driving wheel configured on the rear end of said rear frame. By adopting the above technical scheme, the left and right rocker arms are hinged to the main frame along the same axis. When the tricycle is turned or tilted, they can be always parallel to each other, and the driving will be more stable. The left and right rocker arms are two independent gravity center deflection systems that will not interfere with each other; meanwhile, the structure with single damper can greatly reduce the manufacturing cost of the present invention.

Description:
BACKGROUND OF INVENTION 
       [0001]    1. Field of the Invention 
         [0002]    The present invention relates generally to an inverted tricycle structure. 
         [0003]    2. Description of Related Art 
         [0004]    An inverted tricycle is a special vehicle which has two front steering wheels. In comparison to a bicycle, as it has one more wheel to touch the ground, it offers better stability on slippery road surfaces, and can substantially reduce the possibility of sideslip and fall of the rider. In complex road environments, its driving safety is much better than a bicycle. 
         [0005]    In the structure of a prior-art inverted tricycle, in order to enhance the adaptability of the two front steering wheels to rugged terrains, and make it possible that the vehicle body will not tilt when the ground surfaces touched by the left and right wheels are at different levels, generally the left wheel and right wheel are supported on the left and right ends of the rocker arm through four front dampers. In such a structure, the front dampers are subject to massive lateral forces, which may easily cause failure or danger. Also, in the prior-art inverted tricycle, the main motion components are dispersed on the steering sleeve and suspension system, featuring high gravity centers and indirect motion transmission. Such a far-fetched motion transmission structure will naturally result in a higher rate of failure and lower driving flexibility. Furthermore, the rocker arms are installed on the sleeve of the steering column above the frame, and the steering column sleeve is a hollow piece. This is also an unsafe factor. Moreover, the prior-art main frame structure has insufficient rigidity and the manufacturing processes are quite complicated. Therefore, there is a necessary to improve the prior-art inverted tricycle and deflecting and steering system. 
       SUMMARY OF THE INVENTION 
       [0006]    The technical problem to be solved by the present invention is to overcome defects of the prior art and provide an inverted tricycle, the technical scheme is that an inverted tricycle, including: a deflecting and a steering mechanism, a rear frame, a driving wheel, and two front wheels, said deflecting and steering mechanism being configured on the front end of said rear frame, said two front wheels and said deflecting and steering mechanism being connected, and symmetrically configured on the left and right sides of the front end of the rear frame, with said rear frame as the axis of symmetry, and said driving wheel being configured on the rear end of said rear frame. 
         [0007]    More preferably, wherein said deflecting and steering mechanism of the inverted tricycle includes main frame, left front arm component and right front arm component symmetrically configured on the two sides of said main frame; 
         [0008]    said left front arm component includes left upper rocker arm, left lower rocker arm and left steering joint structure, the first end of said left upper rocker arm is hinged to said main frame through first pivotal structure, the first end of said left lower rocker arm is hinged to said main frame through second pivotal structure, the second ends of said left upper rocker arm and left lower rocker arm are respectively hinged to the upper and lower ends of said left steering joint structure through third pivotal structure and fourth pivotal structure, and the axes of rotation of said first pivotal structure, second pivotal structure, third pivotal structure, and fourth pivotal structure are perpendicular to the same plane; 
         [0009]    said right front arm component includes right upper rocker arm, right lower rocker arm and right steering joint structure, the first end of said right upper rocker arm is hinged to said main frame through fifth pivotal structure, the first end of said right lower rocker arm is hinged to the main frame through sixth pivotal structure, the second ends of said right upper rocker arm and right lower rocker aim are respectively hinged to the upper and lower ends of said right steering joint structure through seventh pivotal structure and eighth pivotal structure, and the axes of rotation of fifth pivotal structure, sixth pivotal structure, seventh pivotal structure, and eighth pivotal structure are perpendicular to the same plane; 
         [0010]    said first pivotal structure and said fifth pivotal structure share the same axis, and said second pivotal structure and said sixth pivotal structure share the same axis; 
         [0011]    the deflecting and steering mechanism of said inverted tricycle also includes a steering structure, said steering structure including front steering column, main steering column, universal steering mechanism, said front steering column equipped through said main frame, the upper end of said front steering column connected to said main steering column, while its lower end connected to the middle position of said universal steering mechanism, the two ends of said universal steering mechanism respectively connected to left steering joint structure and right steering joint structure. 
         [0012]    More preferably, wherein said universal steering mechanism includes cross axle, left connecting rod, and right connecting rod, the lower end of said front steering column hinged to the first axle portion of said cross axle, the second axle portion of said cross axle hinged to said left connecting rod and right connecting rod, said left connecting rod connected to said left steering joint structure and said cross axle, while said right connecting rod connected to said right steering joint structure and said cross axle. 
         [0013]    More preferably, wherein said universal steering mechanism includes left pull rod and right pull rod, the two ends of said left pull rod and said right pull rod respectively configured with rod end knuckle bearings; the inner ring body of the rod end knuckle bearing on the inner side of said left pull rod is connected to the inner ring body of the rod end knuckle bearing on the inner side of said right pull rod. 
         [0014]    More preferably, wherein said left pull rod is connected to said left steering joint structure through the inner ring body of the rod end knuckle bearing on its outer side, said right pull rod is connected to said right steering joint structure through the inner ring body of the rod end knuckle bearing on its outer side; the locking bolt goes through the center hole of the inner ring body of the rod end knuckle bearing on the inner side of said right pull rod as well as the center hole of the inner ring body of the rod end knuckle bearing on the inner side of said left pull rod, and connected to the bottom end of said front steering column. 
         [0015]    More preferably, wherein said left pull rod and said right pull rod are in a back-forth or up-down arrangement. 
         [0016]    More preferably, wherein the connection line between the center point of the inner ring body of the rod end knuckle bearing on the outer side of said left pull rod and the center point of said driving wheel intersects the axis of rotation of said left steering joint structure; the connection line between the center point of the inner ring body of the rod end knuckle bearing on the outer side of said right pull rod and the center point of said driving wheel intersects the axis of rotation of said right steering joint structure. 
         [0017]    More preferably, wherein said main frame includes front frame and main beam, said main beam being in a “C” shape, and said front frame configured on the open side of the “C” shape of said main beam. 
         [0018]    More preferably, wherein said main beam includes said C-shaped beam body, said C-shaped beam body having a top longitudinal extending portion and a bottom longitudinal extending portion; said top longitudinal extending portion, bottom longitudinal extending portion, and C-shaped beam body are formed integrally; the top of said top longitudinal extending portion is provided with a front steering column mounting hole, and the top longitudinal extending portion combines with the front steering column through the front steering column mounting hole; said front steering column is equipped through the front steering column mounting hole of said main beam, and the bottom end of said front steering column extends downward to the inner space of the C shape of the C-shaped beam body of the main beam. 
         [0019]    More preferably, wherein the upper portion of the front side of said top longitudinal extending portion is provided with a front frame upper section connecting hole, while the lower portion of the front side of said top longitudinal extending portion is provided with a front frame middle section connecting hole; the rear side of said top longitudinal extending portion is provided with a rear frame upper section connecting hole; said top longitudinal extending portion fixes and connects to the upper section of the front frame through the front frame upper section connecting hole, and fixes and connects to the middle section of the front frame through the front frame middle section connecting hole; said top longitudinal extending portion fixes and connects to the upper section of the rear frame through the rear frame upper section connecting hole. 
         [0020]    More preferably, wherein the front side of said bottom longitudinal extending portion is provided with a front frame lower section connecting hole; the rear side of said bottom longitudinal extending portion is provided with a rear frame lower section connecting hole; said bottom longitudinal extending portion fixes and connects to the lower section of the front frame through the front frame lower section connecting hole, and fixes and connects to the lower section of the rear frame through the rear frame lower section connecting hole. 
         [0021]    More preferably, wherein the rear side of said C-shaped beam body is provided with a rear frame middle section connecting hole; said C-shaped beam body fixes and connects to the rear frame through the rear frame middle section connecting hole. 
         [0022]    More preferably, wherein said main beam is formed integrally. 
         [0023]    More preferably, wherein said left steering joint structure and right steering joint structure include upper rotary head, lower rotary head, center axle, and sleeve, said center axle connecting said upper rotary head and lower rotary head, said sleeve encasing said center axle, said sleeve and said center axle connected through the bearing, and said sleeve also configured with an axle to mount the wheel. 
         [0024]    More preferably, wherein the center line of the sleeve and the axle to mount the wheel cross each other vertically in a three-dimensional space; a water-proof seal ring is arranged between said sleeve and said center axle. 
         [0025]    More preferably, wherein said deflecting and steering mechanism also includes a wheel unit, said wheel unit equipped on the axle of said sleeve to mount the wheel. 
         [0026]    More preferably, wherein said wheel unit includes a wheel, said wheel provided with an axle hole, with oil seal, bearing, and bearing bush serially configured inside the axle hole, the end cap is configured on the outer end of the axle hole, and a brake disc is fixed on the inner side of the axle hole through a screw; the periphery of said wheel is configured with a spoke, and outside the spoke, a rim is provided. 
         [0027]    More preferably, wherein said left lower rocker arm and said right lower rocker arm are respectively configured with supporting pieces, and a damping system is connected to the supporting pieces on said left and right lower rocker arms. 
         [0028]    More preferably, wherein the upper end of said front steering column is in a ring shape, said left upper rocker arm and said right upper rocker arm are respectively configured with supporting pieces, a damping system is connected to the supporting pieces on said left and right upper rocker arms, and said damping system goes through the ring shape of the upper end of said front steering column. 
         [0029]    More preferably, wherein the axis line of said damping system share the same plane with said left and right steering joint structures. 
         [0030]    Compared with the prior art, the present invention has the beneficial effects are that:
   1. The left and right rocker arms are respectively hinged to the main frame along the same axis, so that they can be always parallel to each other when the tricycle is turned or tilted, and the driving will be more stable. The left and right rocker arms are independent gravity center deflection systems that will not interfere with each other;   2. The steering joint realizes rotation through the universal steering mechanism to turn the vehicle, and the main steering column drives the front steering column, and then drives the universal steering mechanism to move left or right. Under the parallelogram movement mode for left-right steering and left-right deflection within a three-dimensional space, it is guaranteed that, under any condition or any movement mode, the axles of the wheels mounted on the left and right will always be parallel to each other. The middle-positioned two-way cross axle structure in the steering system will not change the original axis of rotation under any movement mode, while maintaining the ability of unsynchronized movement on one side of the left and right rocker arm system. In consideration of the complex structure and high cost of the cross axle, the present invention offers another structural scheme for the universal steering mechanism, wherein the diameter of the inner ring body of the rod end knuckle bearing is enlarged to obtain a larger angle range for rotation. The two inner ring bodies of the two rod end knuckle bearing connecting the front steering column are mounted on the same axle for synchronous movement.   3. The main beam is formed integrally for better strength and rigidity; in the overall arrangement, as the C-shaped opening is facing the front of the vehicle, and meanwhile, the left and right pull rods for steering are arranged in the front, the steering pull rods can have sufficient movement space in the three-dimensional movement relationship. The movement range is substantially enlarged. By leveraging the space of the opening end and the strength of the closed end of the C shape, the movement range of the left and right steering pull rods are enlarged while reducing the overall size of the main frame. Moreover, the main beam of the main frame can be formed integrally in one production.   4. The upper end of the front steering column is in a ring shape. The ring shape can provide avoiding space for the damping mechanism, so that the left and right rocker arms can receive force from the damper more evenly, and the strength of the suspension system of the overall vehicle can be guaranteed with relatively low strength of the rocker arm structure; while reducing the weight under the spring of the suspension system, the stability is substantially enhanced and production and usage costs are also substantially reduced; as the axis line of the damper share the same plane with the axis line of the left and right steering joints, even under abnormal usage conditions, there is no tendency that the front wheel and front damper will interfere with each other. On the premise that the overall length of the damper is fixed, the track width between the two front wheels can be minimized.   
 
         [0035]    Comparing to the prior-art inverted tricycle, the deflecting and steering mechanism of an inverted tricycle developed by us features simpler structure and lower cost. Due to the obvious advantages in technology and cost control, it will surely have a large market. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0036]      FIG. 1  is a schematic structural view of the present invention of an inverted tricycle. 
           [0037]      FIG. 2  is an exploded structural view of the present invention of an inverted tricycle. 
           [0038]      FIG. 3  is a schematic structural view of the deflecting and steering mechanism in the first embodiment of the present invention. 
           [0039]      FIG. 4  is an exploded structural view of the deflecting and steering mechanism in the first embodiment of the present invention. 
           [0040]      FIG. 5  is a schematic structural view of the left side of the deflecting and steering mechanism in the second embodiment of the present invention. 
           [0041]      FIG. 6  is a schematic structural view of the front side of the deflecting and steering mechanism in the second embodiment of the present invention. 
           [0042]      FIG. 7  is an exploded view of the deflecting and steering mechanism in the second embodiment of the present invention. 
           [0043]      FIG. 8  is a schematic structural view of the steering structure in the first embodiment of the present invention. 
           [0044]      FIG. 9  is a schematic structural view of the steering structure in the second embodiment of the present invention. 
           [0045]      FIG. 10  is a forward schematic structural view of the main beam in the first embodiment of the present invention. 
           [0046]      FIG. 11  is a reverse schematic structural view of the main beam in the first embodiment of the present invention. 
           [0047]      FIG. 12  is a schematic structural view of the left and right steering joint structures in the present invention. 
           [0048]      FIG. 13  is an A-A directional view of  FIG. 12 . 
           [0049]      FIG. 14  is a schematic structural view of the wheel in the present invention. 
           [0050]      FIG. 15  is a schematic structural view of the steering structure in the first embodiment of the present invention. 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0051]    Referring to  FIGS. 1 and 2 , a first embodiment of the present invention of an inverted tricycle is disclosed. In this embodiment, the deflecting and steering mechanism of the inverted tricycle includes: deflecting and steering mechanism A 2 , rear frame  6 , driving wheel A 4 , two front wheels A 3 , said deflecting and steering mechanism A 2  being configured on the front end of said rear frame  6 , said two front wheels A 3  and said deflecting and steering mechanism A 2  being connected, and symmetrically configured on the left and right sides of the front end of said rear frame  6 , with said rear frame  6  as the axis of symmetry, and said driving wheel A 4  being configured on the rear end of said rear frame  6 . 
         [0052]      FIGS. 3 and 4  depict the deflecting and steering mechanism A 2  of the first embodiment of the inverted tricycle.  FIGS. 5, 6, and 7  depict another preferred embodiment, i.e., the deflecting and steering mechanism A 2  of the second embodiment of the inverted tricycle. As the two embodiments share similar main structures of the deflecting and steering mechanism A 2 , they are hereby described together. The deflecting and steering mechanism A 2  includes a main frame  1 , symmetrically configured on the left front arm component and right front arm component on the two sides of said main frame  1 . Said left front arm component includes left upper rocker arm  201 , left lower rocker arm  202  and left steering joint structure  203 . The first end of said left upper rocker arm  201  is hinged to said main frame  1  through first pivotal structure  2011 . The first end of said left lower rocker arm  202  is hinged to said main frame  1  through second pivotal structure  2012 . The second ends of said left upper rocker arm  201  and left lower rocker arm  202  are respectively hinged to the upper and lower ends of said left steering joint structure  203  through third pivotal structure  2013  and fourth pivotal structure  2014 . The axes of rotation of said first pivotal structure  2011 , second pivotal structure  2012 , third pivotal structure  2013 , and fourth pivotal structure  2014  are perpendicular to the same plane. 
         [0053]    Said right front aim component includes right upper rocker arm  301 , right lower rocker arm  302  and right steering joint structure  303 . The first end of said right upper rocker arm  301  is hinged to said main frame  1  through fifth pivotal structure  3011 . The first end of said right lower rocker arm  302  is hinged to said main frame  1  through sixth pivotal structure  3012 . The second ends of said right upper rocker arm  301  and right lower rocker arm  302  are respectively hinged to the upper and lower ends of said right steering joint structure  303  through seventh pivotal structure  3013  and eighth pivotal structure  3014 . The axes of rotation of said fifth pivotal structure  3011 , sixth pivotal structure  3012 , seventh pivotal structure  3013 , and eighth pivotal structure  3014  are perpendicular to the same plane. 
         [0054]    Said first pivotal structure  2011  and said fifth pivotal structure  3011  share the same axis. Said second pivotal structure  2012  and said sixth pivotal structure  3012  share the same axis. 
         [0055]    The deflecting and steering mechanism of said inverted tricycle also includes a steering structure. The steering structure of the first embodiment is depicted in  FIG. 8 , being a rod end knuckle bearing structure. The steering structure of the second embodiment is depicted in  FIG. 9 , being a cross axle structure. The cross axle structure is complicated and costly, while in the technical scheme of the first embodiment of the rod end knuckle bearing, the diameter of the inner ring body of the rod end knuckle bearing is enlarged for a larger angle range of rotation. The two inner ring bodies of the two rod end knuckle bearings that are connected with the front steering column are positioned on the same axle for synchronous movement. 
         [0056]    Said steering structure includes front steering column  401 , main steering column  402 , cross axle  403 , left connecting component, said front steering column  401  equipped through said main frame  1 , said deflecting and steering mechanism being a left-right symmetric structure, said front steering column  401  going through the symmetric plane of said main frame  1 , the upper end of said front steering column  401  is connected with said main steering column  402 , while its lower end is connected to the middle position of said universal steering mechanism, the two ends of said universal steering mechanism are respectively connected to said left steering joint structure  203  and right steering joint structure  303 . 
         [0057]    The universal steering mechanism of the first embodiment is depicted in  FIG. 8 , and includes left pull rod  404 , right pull rod  405 , the two ends of left pull rod  404  and right pull rod  405  respectively configured with rod end knuckle bearings; 
         [0058]    The inner ring body  901  of the rod end knuckle bearing on the inner side of the left pull rod  404  is fixed and connected to the inner ring body  902  of the rod end knuckle bearing on the inner side of the right pull rod  405 ; said left pull rod  404  is connected to the left steering joint structure  203  through the inner ring body  903  of the rod end knuckle bearing on its outer side, while said right pull rod  405  is connected to the right steering joint structure  303  through the inner ring body  904  of the rod end knuckle bearing on its outer side; the locking bolt passes through the center hole of the inner ring body  902  of the rod end knuckle bearing on the inner side of the right pull rod  405  as well as the center hole of the inner ring body  901  of the rod end knuckle bearing on the inner side of the left pull rod  404  and connected to the bottom end of the front steering column  401 . The assembled structure is depicted in  FIG. 15 . The connecting line between the center point of the inner ring body  903  of the rod end knuckle bearing on the outer side of said left pull rod  404  and the center point Z of the driving wheel A 4  intersects the axis of rotation of the left steering joint structure  203 ; the connecting line between the center point of the inner ring body  904  of the rod end knuckle bearing on the outer side of said right pull rod  405  and the center point Z of the driving wheel A 4  intersects the axis of rotation of the right steering joint structure  303 . 
         [0059]    Said left pull rod  404  and right pull rod  405  are in a back-forth or up-down arrangement. 
         [0060]    The universal steering mechanism in the second embodiment is depicted in  FIG. 9 , including a cross axle  403 , left connecting rod  404 , and right connecting rod  405 , the lower end of said front steering column  401  being hinged to the first axle portion of said cross axle  403 , the second axle portion of said cross axle  403  is hinged to said left connecting rod  404  and right connecting rod  405 , said left connecting rod  404  being connected to said left steering joint structure  203  and said cross axle  403 , said right connecting rod  405  being connected to said right steering joint structure  303  and said cross axle  403 . Said left steering joint structure  203  and said left connecting rod  404  are also connected through a cross axle, said right steering joint structure  303  and said right connecting rod  405  are also connected through a cross axle. 
         [0061]    In the first embodiment, the main frame  1  includes front frame  102  and main beam  101 , said main beam  101  being in a “C” shape, said front frame  102  being configured on the side of the opening of the “C” shape of the main beam  101 . Referring to  FIG. 10  and  FIG. 11 , said main beam  101  includes said C-shaped beam body  1011 , said C-shaped beam body  1011  having a top longitudinal extending portion  1012  and a bottom longitudinal extending portion  1013 ; Said top longitudinal extending portion  1012 , bottom longitudinal extending portion  1013  and C-shaped beam body  1011  are integrally formed. The top of said top longitudinal extending portion  1012  is provided with a front steering column mounting hole  1014 , and the top longitudinal extending portion  1012  combines with the front steering column  401  through the front steering column mounting hole  1014 . Said front steering column  401  is equipped through the front steering column mounting hole  1014  of main beam  101 , and the bottom end of said front steering column  401  extends downward to the inner space of the C shape of the C-shaped beam body  1011  of the main beam  101 . 
         [0062]    The upper portion of the front side of said top longitudinal extending portion  1012  is provided with a front frame  102  upper section connecting hole  1015 , while the lower portion of the front side of said top longitudinal extending portion  1012  is provided with a front frame  102  middle section connecting hole  1016 ; the rear side of said top longitudinal extending portion  1012  is provided with a rear frame  6  upper section connecting hole  1017 ; said top longitudinal extending portion  1012  fixes and connects to the upper section of the front frame  102  through the front frame  102  upper section connecting hole  1015 , and fixes and connects to the middle section of the front frame  102  through the front frame  102  middle section connecting hole  1016 ; said top longitudinal extending portion  1012  fixes and connects to the upper section of the rear frame  6  through the rear frame  6  upper section connecting hole  1017 . 
         [0063]    The front side of said bottom longitudinal extending portion  1013  is provided with a front frame  102  lower section connecting hole  1018 ; the rear side of said bottom longitudinal extending portion  1013  is provided with a rear frame  6  lower section connecting hole  1019 ; 
         [0064]    Said bottom longitudinal extending portion  1013  fixes and connects to the lower section of the front frame  102  through the front frame  102  lower section connecting hole, and fixes and connects to the lower section of the rear frame  6  through the rear frame  6  lower section connecting hole  1019 . 
         [0065]    Meanwhile, the upper portion of the front side of said top longitudinal extending portion  1012  is provided with a front frame  102  upper section connecting hole  1015 , and the rear frame  6  upper section connecting hole  1017  provided on the rear side of said top longitudinal extending portion  1012  shares the same axle hole, to fix the left upper rocker arm  201  and right upper rocker arm  301  together, to form a pivotal structure. 
         [0066]    The front frame  102  lower section connecting hole  1018  provided on the front side of said bottom longitudinal extending portion  1013  and the rear frame  6  lower section connecting hole  1019  provided on the rear side of said bottom longitudinal extending portion  1013  share the same axle hole, to fix the left lower rocker arm  202  and right lower rocker arm  302  together, to foam a pivotal structure. 
         [0067]    The rear side of said C-shaped beam body  101  is provided with a rear frame  6  middle section connecting hole  1020 ; said C-shaped beam body  101  fixes and connects to the rear frame  6  through the rear frame  6  middle section connecting hole  1020 . 
         [0068]    Said main beam  101  is integrally formed in a C shape to offer better strength. It is a change to the complex structure of the prior-art main frame, and the manufacturing processes are simplified. 
         [0069]    Referring to  FIG. 12  and  FIG. 13 , said left steering joint structure  203  and right steering joint structure  303  include upper rotary head  2031 , lower rotary head  2032 , center axle  2033 , and sleeve  2034 , said center axle  2033  connecting said upper rotary head  2031  and lower rotary head  2032 , said sleeve  2034  encasing said center axle  2033 , said sleeve  2034  and said center axle  2033  connected through the bearing  2036 , and said sleeve  2034  also configured with an axle  2035  to mount the wheel. Said upper rotary head  2031  and upper rocker arm form said first pivotal structure  2013  and said fifth pivotal structure  3013 , while said lower rotary head  2032  and lower rocker arm form said first pivotal structure  2014  and said fifth pivotal structure  3014 . Said first pivotal structure  2013 ,  2014 , and said fifth pivotal structure  3013 ,  3014  are both hinge structures. 
         [0070]    The center line of said sleeve  2034  and the axle  2035  to mount the wheel cross each other vertically in a three-dimensional space; a water-proof seal ring  2037  is arranged between said sleeve  2034  and said center axle  2033 . 
         [0071]    Referring to  FIG. 14 , the deflecting and steering mechanism of said inverted tricycle also includes a wheel unit, said wheel unit equipped on the axle  2035  of said sleeve  2034  to mount the wheel. 
         [0072]    Said wheel unit includes a wheel  601 , said wheel  601  provided with an axle hole, with oil seal  602 , bearing  604 , and bearing bush  603  serially configured inside the axle hole, the end cap  605  is configured on the outer side end of the axle hole, and a brake disc  606  is fixed on the inner side of the axle hole through a screw  607 ; the periphery of said wheel is configured with a spoke, and outside the spoke, a rim is provided. 
         [0073]    Referring to  FIGS. 3 and 4 , the upper end  4018  of said front steering column  401  is in a ring shape, said left upper rocker arm and said right upper rocker arm are respectively configured with supporting pieces, a damping system  5  is connected to the supporting pieces on said left and right upper rocker arms, and said damping system  5  goes through the ring shape of the upper end  4018  of said front steering column. 
         [0074]    The axis line of said damping system  5  shares the same plane with said left and right steering joint structures  203 ,  303 . Therefore, even under abnormal usage conditions, there is no tendency that the front wheel and the damping system will interfere with each other. On the premise that the overall length of the damper is fixed, the track width between the two front wheels can be minimized. 
         [0075]    In the second embodiment, referring to  FIGS. 5, 6, and 7 , said left lower rocker arm  202  and said right lower rocker arm  302  are respectively configured with supporting pieces, and a damping system  5  is connected to the supporting pieces on said left and right lower rocker arms. Alternatively, the layout structure of the front steering column and damping system in the first embodiment can also be adopted. 
         [0076]    Although the invention has been explained in relation to its preferred embodiment, it is to be understood that many other possible modifications and variations can be made without departing from the spirit and scope of the invention as hereinafter claimed.