Patent Publication Number: US-2023150327-A1

Title: Rear suspension system of an all-terrain vehicle and all-terrain vehicle

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
     The present disclosure claims priority to Chinese Application No. 202122809192.9 filed on Nov. 16, 2021, and entitled REAR SUSPENSION SYSTEM OF AN ALL-TERRAIN VEHICLE AND ALL-TERRAIN VEHICLE, and Chinese Application No. 202111357388.7 filed on Nov. 16, 2021, and entitled “ALL-TERRAIN VEHICLE”, all of which are incorporated herein by reference in their entirety. 
     TECHNICAL FIELD 
     This disclosure relates to the technical field of all-terrain vehicles, and in particular, to a rear suspension system of an all-terrain vehicle and an all-terrain vehicle. 
     BACKGROUND 
     Currently, a suspension system is mainly used in a road and off-road dual-purpose vehicle. A chassis and a suspension system of the vehicle need to have a large movement journey, a barrier passing capability, and an off-road capability, and a rear suspension system of the vehicle mostly uses a multi-link suspension structure. However, a current rear suspension system still has some shortcomings in wheel positioning, and suspension comfort and support force in various driving conditions. 
     SUMMARY 
     Embodiments of this disclosure are intended to resolve at least one of technical problems in the prior art. Therefore, an embodiment of this disclosure provides a rear suspension system of an all-terrain vehicle. In a moving process of the all-terrain vehicle, moving directions of suspension links (for example, a main control arm, a front upper control arm, and a rear upper control arm) are limited to straight lines parallel to each other, thereby reducing impact of movements of the suspension links on an axle support, and further ensuring an accurate and reasonable wheel positioning characteristic. The rear suspension system of the all-terrain vehicle may reduce a tilt of a vehicle body to a maximum extent, maintain ground-sticking performance of wheels, and maintain wheel positioning that meets a driving requirement of the all-terrain vehicle, to meet suspension comfort and support force required by the all-terrain vehicle in various driving conditions. 
     An embodiment of this disclosure further provides an all-terrain vehicle. 
     The rear suspension system of an all-terrain vehicle according to the embodiment of this disclosure includes a left rear suspension assembly and a right rear suspension assembly. The left rear suspension assembly and the right rear suspension assembly are disposed opposite to each other in a left-right direction. The left rear suspension assembly and the right rear suspension assembly each include: an axle support; a main control arm, where the main control arm has a first outer end, a first inner end, and a second inner end, and the first outer end is rotatably connected to the axle support; a front upper control arm, where the front upper control arm has a second outer end and a third inner end, and the second outer end is rotatably connected to the axle support; a rear upper control arm, where the rear upper control arm has a third outer end and a fourth inner end, the third outer end is rotatably connected to the axle support. A center connection line between the first inner end and the second inner end is L 1 , a center axis of the first outer end is L 2 , a center connection line of the third inner end and the fourth inner end is L 3 , a center connection line of the second outer end and the third outer end is L 4 , and L 1 , L 2 , L 3 , and L 4  are parallel to each other. 
     In the rear suspension system of an all-terrain vehicle in this embodiment of this disclosure, the left rear suspension assembly and the right rear suspension assembly may form a multi-link suspension structure. In this way, the all-terrain vehicle may have certain comfort. In addition, the wheels are controlled and positioned through the multi-link suspension structure, so that the wheels and the ground are vertical as far as possible, the tilt of the vehicle body is reduced to the maximum extent, and the ground-sticking performance of the wheels is maintained. In addition, L 1 , L 2 , L 3 , and L 4  are parallel to each other, so that wheel positioning that meets the driving requirement of the all-terrain vehicle can be maintained, to meet the suspension comfort and support force required by the all-terrain vehicle in various driving conditions. 
     In some examples of this disclosure, a vertical plane that passes through a midpoint of a center connection line of the two axle supports of the left rear suspension assembly and the right rear suspension assembly is a first reference plane, and the left rear suspension assembly and the right rear suspension assembly are symmetrically disposed relative to the first reference plane. 
     In some examples of this disclosure, the first inner end is located in front of the second inner end, a distance from the first inner end to the first reference plane is a 1 , a distance from the second inner end to the first reference plane is a 2 , and a 1  and a 2  meet a relational expression: a 1 &gt;a 2 . 
     In some examples of this disclosure, a horizontal plane that passes through the center connection line of the two axle supports is a second reference plane, an angle between a projection of L 1  on the second reference plane and a projection of the first reference plane on the second reference plane is α, and α meets a relational expression: 10°≤α≤25°. 
     In some examples of this disclosure, the axle support includes a main support, an upper mounting part, and a lower mounting part, both the upper mounting part and the lower mounting part are disposed on the main support and protrude inward, the first outer end is connected to the lower mounting part, and the second outer end and the third outer end are connected to the upper mounting part. 
     In some examples of this disclosure, the rear suspension system further includes a stabilizer bar, where two ends of the stabilizer bar are respectively connected to the main control arm of the left rear suspension assembly and the main control arm of the right rear suspension assembly. The left rear suspension assembly and the right rear suspension assembly each include a shock absorber, where a lower end of the shock absorber is disposed on the main control arm. 
     In some examples of this disclosure, the main control arm includes a first rod and a second rod, the first rod is located in front of the second rod, an outer end of the first rod is connected to an outer end of the second rod to form the first outer end, an inner end of the first rod is the first inner end, an inner end of the second rod is the second inner end, the ends of the stabilizer bar and the lower end of the shock absorber are disposed on the first rod or the second rod, the ends of the stabilizer bar are disposed adjacent to a midpoint of the first rod or the second rod, and the lower end of the absorber is disposed adjacent to the first outer end. 
     In some examples of this disclosure, the rear suspension system of an all-terrain vehicle further includes a ball joint bearing. The outer ends of the main control arm, the front upper control arm, and the rear upper control arm are connected to the axle support through the ball joint bearing. 
     An embodiment of this disclosure further provides another all-terrain vehicle, including: a frame; a cockpit, disposed in the middle of the frame, where two seats are disposed side by side in the cockpit; wheels, supporting the frame and including front wheels and rear wheels; a front suspension system, connecting the front wheels to the frame; and a rear suspension system, connecting the rear wheels to the frame. The rear suspension system includes a left rear suspension assembly and a right rear suspension assembly. The left rear suspension assembly and the right rear suspension assembly are disposed opposite to each other in a left-right direction. The left rear suspension assembly and the right rear suspension assembly each include: an axle support; a main control arm, where a mounting base is disposed on the main control arm, the main control arm has a first outer end, a first inner end, and a second inner end, and the first outer end is rotatably connected to the axle support; a front upper control arm, where the front upper control arm has a second outer end and a third inner end, and the second outer end is rotatably connected to the axle support; a rear upper control arm, where the front upper control arm and the rear upper control arm each are of a rod-like structure, the rear upper control arm has a third outer end and a fourth inner end, the third outer end is rotatably connected to the axle support. A center connection line between the first inner end and the second inner end is L 1 , a center axis of the first outer end is L 2 , a center connection line of the third inner end and the fourth inner end is L 3 , a center connection line of the second outer end and the third outer end is L 4 , and L 1 , L 2 , L 3 , and L 4  are parallel to each other. 
     In the all-terrain vehicle in this embodiment of this disclosure, the left rear suspension assembly and the right rear suspension assembly may form a multi-link suspension structure. In this way, the all-terrain vehicle may have certain comfort. In addition, the wheels are controlled and positioned through the multi-link suspension structure, so that the wheels are perpendicular to the ground as far as possible, the tilt of the vehicle body is reduced to the maximum extent, and ground-sticking performance of the wheels is maintained. In addition, L 1 , L 2 , L 3 , and L 4  are parallel to each other, so that wheel positioning that meets a driving requirement of the all-terrain vehicle can be maintained, to meet suspension comfort and support force required by the all-terrain vehicle in various driving conditions. 
     In some examples of this disclosure, the main control arm includes a first rod and a second rod, the first rod is located in front of the second rod, an outer end of the first rod is fixedly connected to an outer end of the second rod to form the first outer end, an inner end of the first rod is the first inner end, an inner end of the second rod is the second inner end. 
     In some examples of this disclosure, the all-terrain vehicle further includes a stabilizer bar and shock absorbers. Two ends of the stabilizer bar are respectively connected to the main control arm of the left rear suspension assembly and the main control arm of the right rear suspension assembly, and lower ends of the shock absorbers are disposed on the main control arms. 
     In some examples of this disclosure, the ends of the stabilizer bar and the lower ends of the shock absorbers are disposed on the first rod or the second rod, the ends of the stabilizer bar are disposed adjacent to a midpoint of the first rod or the second rod, and the lower ends of the shock absorbers are disposed adjacent to the first outer ends. 
     In some examples of this disclosure, a vertical plane that passes through a midpoint of a center connection line of the two axle supports of the left rear suspension assembly and the right rear suspension assembly is a first reference plane, and the left rear suspension assembly and the right rear suspension assembly are symmetrically disposed relative to the first reference plane. 
     In some examples of this disclosure, the first inner end is located in front of the second inner end, a distance from the first inner end to the first reference plane is a 1 , a distance from the second inner end to the first reference plane is a 2 , and a 1  and a 2  meet a relational expression: a 1 &gt;a 2 . 
     In some examples of this disclosure, a horizontal plane that passes through the center connection line of the two axle supports is a second reference plane, an angle between the projection of L 1  on the second reference plane and the projection of the first reference plane on the second reference plane is a, and a meets a relational expression: 10°≤α≤25°. 
     In some examples of this disclosure, the all-terrain vehicle further includes a ball joint bearing. The outer ends of the main control arm, the front upper control arm, and the rear upper control arm are connected to the axle support through the ball joint bearing. 
     In some examples of this disclosure, the axle support includes a main support, an upper mounting part, and a lower mounting part, both the upper mounting part and the lower mounting part are disposed on the main support and protrude inward, the first outer end is connected to the lower mounting part, and the second outer end and the third outer end are connected to the upper mounting part. 
     The all-terrain vehicle according to this embodiment of this disclosure includes the foregoing rear suspension system of an all-terrain vehicle. 
     Some of additional aspects and advantages of this disclosure are provided in the following descriptions, and some of the additional aspects and advantages will become apparent from the following descriptions, or may be learned from practice of this disclosure. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The foregoing and/or additional aspects and advantages of this disclosure will become apparent and readily understood from descriptions of embodiments with reference to the following drawings. 
         FIG.  1    is a schematic diagram of a structure of a rear suspension system according to an embodiment of this disclosure; 
         FIG.  2    is a schematic diagram of a partial structure of a rear suspension system according to an embodiment of this disclosure; 
         FIG.  3    is a partial exploded view of a rear suspension system according to an embodiment of this disclosure; and 
         FIG.  4    is a schematic diagram of a structure of an all-terrain vehicle according to another embodiment of this disclosure. 
     
    
    
     REFERENCE NUMERALS 
     
         
           1 : rear suspension system;  10 : left rear suspension assembly;  20 : right rear suspension assembly;  30 : axle support;  31 : main support;  32 : upper mounting part;  33 : lower mounting part;  40 : main control arm;  41 : first outer end;  42 : first inner end;  43 : second inner end;  44 : first rod;  45 : second rod;  46 : mounting base;  50 : front upper control arm;  51 : second outer end;  52 : third inner end;  60 : rear upper control arm;  61 : third outer end;  62 : fourth inner end;  70 : stabilizer bar;  80 : shock absorber;  2 : all-terrain vehicle;  90 : frame;  100 : wheels;  101 : front wheel;  102 : rear wheel;  110 : cockpit;  111 : seat;  120 : front suspension system; B 1 : ball joint bearing; and P 1 : first reference plane. 
       
    
     DETAILED DESCRIPTION 
     The following describes the embodiments of this disclosure in detail. The embodiments described with reference to the drawings are exemplary. The following describes the embodiments of this disclosure in detail. 
     Refer to  FIG.  1    to  FIG.  4   . The following describes a rear suspension system  1  of an all-terrain vehicle  2  according to an embodiment of this disclosure. The rear suspension system  1  is disposed on the terrain vehicle  2 , and certainly, may also be applied to another off-road vehicle. 
     As shown in  FIG.  1    to  FIG.  4   , the rear suspension system  1  of the all-terrain vehicle  2  according to this embodiment of this disclosure includes a left rear suspension assembly  10  and a right rear suspension assembly  20 . The left rear suspension assembly  10  and the right rear suspension assembly  20  are disposed between a frame  90  and wheels  100  of the all-terrain vehicle  2 , and play a role of supporting and controlling. The left rear suspension assembly  10  and the right rear suspension assembly  20  are disposed opposite to each other in a left-right direction. The left rear suspension assembly  10  acts between the frame  90  and the left wheels  100 , and the right rear suspension assembly  20  acts between the frame  90  and the right wheels  100 , so that the wheels  100  on both sides of the all-terrain vehicle  2  can be controlled, and the all-terrain vehicle  2  is more stable, more comfortable, and safer in a driving process. 
     As shown in  FIG.  1    to  FIG.  3   , the left rear suspension assembly  10  and the right rear suspension assembly  20  each include: an axle support  30 , a main control arm  40 , a front upper control arm  50 , and a rear upper control arm  60 . The axle support  30 , the main control arm  40 , the front upper control arm  50 , and the rear upper control arm  60  are connected to each other. In addition, the main control arm  40 , the front upper control arm  50 , and the rear upper control arm  60  are also connected to the frame  90 . In this way, a multi-link suspension structure may be formed. The multi-link suspension structure can ensure certain comfort, and the wheels  100  are controlled and positioned through the multi-link suspension structure, so that the wheels  100  are perpendicular to the ground as far as possible, a tilt of a vehicle body is reduced to the maximum extent, and ground-sticking performance of the wheels  100  is maintained. The main control arm  40  may play a role of adjusting a toe-in of the wheels  100 , and endures vertical load and left-right unbalance force from the wheels  100 , to improve driving stability of the all-terrain vehicle  2 , and effectively reduce friction of the wheels  100 . The front upper control arm  50  and the rear upper control arm  60  jointly control camber angles of the wheels  100  with the main control arm  40 , and endure cornering force from the wheels  100 . In addition, the main control arm  40  may be a tube member, a steel plate stamping member, or a forged casting member. 
     Specifically, as shown in  FIG.  1    to  FIG.  3   , the main control arm  40  has a first outer end  41 , a first inner end  42 , and a second inner end  43 . The first outer end  41  is rotatably connected to the axle support  30 . The first inner end  42  and the second inner end  43  are connected to the frame  90 . The front upper control arm  50  has a second outer end  51  and a third inner end  52 . The second outer end  51  is rotatably connected to the axle support  30 . The third inner end  52  is connected to the frame  90 . The rear upper control arm  60  has a third outer end  61  and a fourth inner end  62 . The third outer end  61  is rotatably connected to the axle support  30 . The fourth inner end  62  is connected to the frame  90 . In this way, an integral structure of the left rear suspension assembly  10  and the right rear suspension assembly  20  is connected more stably, and can form a multi-link suspension structure together with the frame  90 , thereby improving performance of the left rear suspension assembly  10  and the right rear suspension assembly  20 . 
     As shown in  FIG.  2    and  FIG.  3   , a center connection line between the first inner end  42  and the second inner end  43  is L 1 , a center axis of the first outer end  41  is L 2 , a center connection line between the third inner end  52  and the fourth inner end  62  is L 3 , a center connection line between the second outer end  51  and the third outer end  61  is L 4 , and L 1 , L 2 , L 3 , and L 4  are parallel to each other. It should be noted that, in a moving process of the all-terrain vehicle  2 , the first inner end  42  and the second inner end  43  may move in a direction of L  1 , the third inner end  52  and the fourth inner end  62  may move in a direction of L 3 , the second outer end  51  and the third outer end  61  may move in a direction of L 4 , and the width of the first outer end  41  may change in a direction of L 2 . These movements do not change a positioning characteristic of the wheels  100  since L 1 , L 2 , L 3 , and L 4  are parallel to each other, and the wheel  100  positioning that meets a driving requirement of the all-terrain vehicle  2  can always be maintained. Certainly, a position may be adjusted according to a need for structural arrangement of the rear suspension system  1 . 
     Therefore, the left rear suspension assembly  10  and the right rear suspension assembly  20  may form a multi-link suspension structure. In this way, the all-terrain vehicle  2  may have certain comfort. In addition, the wheels  100  are controlled and positioned through the multi-link suspension structure, so that the wheels  100  are perpendicular to the ground as far as possible, the tilt of the vehicle body is reduced to the maximum extent, and the ground-sticking performance of the wheels  100  is maintained. In addition, L 1 , L 2 , L 3 , and L 4  are parallel to each other, so that the wheel  100  positioning that meets the driving requirement of the all-terrain vehicle  2  can be maintained, to meet suspension comfort and support force required by the all-terrain vehicle  2  in various driving conditions. 
     As shown in  FIG.  2   , a vertical plane that passes through a midpoint of a center connection line of the two axle supports  30  is a first reference plane P 1 , and the left rear suspension assembly  10  and the right rear suspension assembly  20  are symmetrically disposed relative to the first reference plane P 1 . The left rear suspension assembly and the right rear suspension assembly have same component structures and same operating principles. The left rear suspension assembly  10  and the right rear suspension assembly  20  are symmetrically disposed relative to the vertical plane of the midpoint of the center connection line of the two axle supports  30 . In this way, the left rear suspension assembly  10  and the right rear suspension assembly  20  may respectively act on the left wheels  100  and the right wheels  100  of the all-terrain vehicle  2 , so that an effect on the left wheels  100  and an effect on the right wheels  100  are the same, and the suspension comfort and a support effect of the all-terrain vehicle  2  are better. 
     Certainly, as shown in  FIG.  2   , the first inner end  42  is located in front of the second inner end  43 , a distance from the first inner end  42  to the first reference plane P 1  is a 1 , a distance from the second inner end  43  to the first reference plane P 1  is a 2 , and a 1  and a 2  meet a relational expression: a 1 &gt;a 2 . The first inner end  42  is located on the front side of the second inner end  43 , and such an arrangement is reasonable. Because a plurality of parts need to be disposed between the first inner ends  42  of the left rear suspension assembly and the right rear suspension assembly, and there is no such requirement between two second inner ends  43 , the distance from the first inner end  42  to the first reference plane P 1  needs to be greater than the distance from the second inner end  43  to the first reference plane P 1 . 
     In addition, as shown in  FIG.  2   , a horizontal plane that passes through the center connection line L 10  of the two axle supports  30  is a second reference plane, an angle between the projection of L 1  on the second reference plane and the projection of the first reference plane P 1  on the second reference plane is a, and a meets a relational expression: 10°≤α≤25°. There is a certain relationship between an angle between L 1  and the first reference plane P 1  and a travel of the wheels  100  of the all-terrain vehicle  2 . A range of the angle between L 1  and the first reference plane P 1  is set to 10°≤α≤25°, which is reasonable. When the travel of the wheels  100  of the all-terrain vehicle  2  is small, the angle between L 1  and the first reference plane P 1  needs to be set to be smaller. When the travel of the wheel  100  of the all-terrain vehicle  2  is large, the angle between L 1  and the first reference plane P 1  needs to be set to be larger. In this way, the angle may be better coordinated with the wheels  100 . In addition, the angle between L 1  and the first reference plane P 1  is set to be in an appropriate range, so that a stretching length of the main control arm  40  can be longer, and performance of the main control arm  40  can be better. 
     In addition, as shown in  FIG.  1   , the first inner end  42  is located in a front inner side of the third inner end  52 , and the second inner end  43  is located in a front inner side of the fourth inner end  62 . In this way, the first inner end  42  and the second inner end  43  are closer to the inner side, so that the stretching length of the main control arm  40  is longer, and the performance of the main control arm  40  is better. 
     Specifically, as shown in  FIG.  1    and  FIG.  3   , the axle support  30  includes a main support  31 , an upper mounting part  32 , and a lower mounting part  33 . Both the upper mounting part  32  and the lower mounting part  33  are disposed on the main support  31 , and both the upper mounting part  32  and the lower mounting part  33  protrude inward. The first outer end  41  is connected to the lower mounting part  33 , and the second outer end  51  and the third outer end  61  are connected to the upper mounting part  32 . Both the upper mounting part  32  and the lower mounting part  33  are disposed on the main support  31 . In this way, the main support  31 , the upper mounting part  32 , and the lower mounting part  33  may form an integrated body, to facilitate mounting of the axle support  30 . The first outer end  41  is connected to the lower mounting part  33 , and the second outer end  51  and the third outer end  61  are connected to the upper mounting part  32 . In this way, the main control arm  40 , the front upper control arm  50 , and the rear upper control arm  60  are connected to the axle support  30 , so that structures of the left rear suspension assembly and the right rear suspension assembly are more integrated, and a structure of the first outer end  41  is different from structures of the second outer end  51  and the third outer end  61 . 
     Optionally, as shown in  FIG.  1   , the rear suspension system  1  further includes a stabilizer bar  70 . Two ends of the stabilizer bar  70  are respectively connected to the main control arm  40  of the left rear suspension assembly  10  and the main control arm  40  of the right rear suspension assembly  20 . The left rear suspension assembly  10  and the right rear suspension assembly  20  each include a shock absorber  80 , where a lower end of the shock absorber  80  is disposed on the main control arm  40 . The two ends of the stabilizer bar  70  are respectively connected to the main control arm  40  of the left rear suspension assembly  10  and the main control arm  40  of the right rear suspension assembly  20 . In this way, the stabilizer bar  70  may play a role of connection, and the left rear suspension assembly  10  and the right rear suspension assembly  20  are connected to form an integrated rear suspension system  1 . Certainly, the stabilizer bar  70  is disposed in a transverse direction, and the stabilizer bar  70  may improve roll angle stiffness of the rear suspension system  1  and reduce an angle of tilt of the vehicle body of the all-terrain vehicle  2 . The left rear suspension assembly  10  and the right rear suspension assembly  20  each are provided with a shock absorber  80 . The shock absorber  80  includes a spring and a hydraulic damper. An upper end of the shock absorber is connected to the frame  90 , and a lower end of the shock absorber is disposed on the main control arm  40 . When the rear suspension system  1  works, the shock absorber  80  generates a telescopic movement. When the spring is compressed, the spring may absorb impact energy from the ground through the wheels  100 , the absorbed energy is released when the spring stretches, and the released energy is converted into heat for dissipation by the hydraulic damper. In this way, a shock absorption effect of the rear suspension system  1  can be implemented, thereby improving comfort of a user when driving the all-terrain vehicle  2 . 
     In addition, as shown in  FIG.  1    to  FIG.  3   , the main control arm  40  includes a first rod  44  and a second rod  45 . The first rod  44  is located in front of the second rod  45 , an outer end of the first rod  44  is connected to an outer end of the second rod  45 , the outer end of the first rod  44  and the outer end of the second rod  45  form the first outer end  41 , an inner end of the first rod  44  is the first inner end  42 , an inner end of the second rod  45  is the second inner end  43 , ends of the stabilizer bar  70  and the lower end of the shock absorber  80  are disposed on the first rod  44  or the second rod  45 , the ends of the stabilizer bar  70  are disposed adjacent to a midpoint of the first rod  44  or the second rod  45 , and the lower end of the absorber  80  is disposed adjacent to the first outer end  41 . In other words, one end of the first rod  44  that is close to the inner side is the first inner end  42 , one end of the second rod  45  that is close to the inner side is the second inner end  43 , and one end of the first rod  44  that is close to the outer side is connected to one end of the second rod  45  that is close to the outer side through the first outer end  41 . The ends of the stabilizer bar  70  and the lower end of the shock absorber  80  are disposed on the first rod  44  or the second rod  45 , and the ends of the stabilizer bar  70  are disposed adjacent to the midpoint of the first rod  44  or the second rod  45 , to facilitate connection and mounting of the stabilizer bar  70  and the shock absorber  80 . Therefore, the overall structure of the rear suspension system  1  is adapted to the structure of the all-terrain vehicle  2 , and interference between the mounting of the stabilizer bar  70  and the shock absorber  80  and another structure may also be avoided. It should be noted that the main control arm  40  is not limited to be constructed to have the first rod  44  and the second rod  45 , but may alternatively be constructed to have another reasonable structure. Certainly, the ends of the stabilizer rod  70  and the lower end of the shock absorber  80  may alternatively be disposed on the front upper control arm  50 , which may be specifically limited and selected based on an actual situation. 
     Certainly, the rear suspension system  1  further includes a ball joint bearing B 1 , and the outer ends of the main control arm  40 , the front upper control arm  50 , and the rear upper control arm  60  are all connected to the axle support  30  through the ball joint bearing B 1 . The ball joint bearing B 1  may play a role of mounting and connection, and may rotate and sway at any angle during movement. The outer ends of the main control arm  40 , the front upper control arm  50 , and the rear upper control arm  60  are all connected to the axle support  30  through the ball joint bearing B 1 . In this way, the main control arm  40 , the front upper control arm  50 , and the rear upper control arm  60  may move relative to the axle support  30 , these movements do not change a positioning characteristic of the wheels  100 , and the wheel  100  positioning that meets the driving requirement of the all-terrain vehicle  2  can always be maintained. 
     As shown in  FIG.  4   , the all-terrain vehicle  2  according to this embodiment of this disclosure includes the rear suspension system  1  of the all-terrain vehicle  2  described in the foregoing embodiment. The all-terrain vehicle  2  may control positioning of the wheels  100  through the rear suspension system  1 . In this way, the suspension comfort and support force required by the all-terrain vehicle  2  in various driving conditions can be met. 
     The following describes another all-terrain vehicle  2  according to an embodiment of this disclosure with reference to  FIG.  1    to  FIG.  4   . 
     As shown in  FIG.  4   , the all-terrain vehicle  2  according to an embodiment of this disclosure includes a frame  90 , a cockpit  110 , wheels  100 , a front suspension system  120 , and a rear suspension system  1 . The frame  90  may play a role of mounting and supporting the whole all-terrain vehicle  2 , and form a whole frame of the all-terrain vehicle  2 . The cockpit  110  is disposed in the middle of the frame  90  and is mainly used for driving the all-terrain vehicle  2  by a driver, and two seats  111  are disposed side by side in the cockpit  110 . In this way, the driver may sit on the seat  111  for operation, so that comfort of driving by the driver can be improved. In addition, the two seats  111  are disposed, and this arrangement is reasonable, so that two persons may ride at the same time. 
     As shown in  FIG.  3   , the wheels  100  may mainly drive the all-terrain vehicle  2  to move, and may be used to support the frame  90 . The wheels  100  include front wheels  101  and rear wheels  102 . The front suspension system  120  mainly connects the front wheels  101  to the frame  90 , and the rear suspension system  1  mainly connects the rear wheels  102  to the frame  90 . In this way, the wheels  100  may be better connected to the frame  90 , and the all-terrain vehicle  2  may be driven to move as a whole by the wheels. In addition, the all-terrain vehicle  2  may control positioning of the wheels  100  by using the rear suspension system  1 . In this way, suspension comfort and support force required by the all-terrain vehicle  2  in various driving conditions can be met. 
     The rear suspension system  1  includes a left rear suspension assembly  10  and a right rear suspension assembly  20 . The left rear suspension assembly  10  and the right rear suspension assembly  20  are disposed between the frame  90  and the wheels  100  of the all-terrain vehicle  2 , and play a role of supporting and controlling. The left rear suspension assembly  10  and the right rear suspension assembly  20  are disposed opposite to each other in a left-right direction. The left rear suspension assembly  10  acts between the frame  90  and the left wheels  100 , and the right rear suspension assembly  20  acts between the frame  90  and the right wheels  100 , so that the wheels  100  on both sides of the all-terrain vehicle  2  can be controlled, and the all-terrain vehicle  2  is more stable, more comfortable, and safer in a driving process. 
     As shown in  FIG.  1    to  FIG.  3   , the left rear suspension assembly  10  and the right rear suspension assembly  20  each include: an axle support  30 , a main control arm  40 , a front upper control arm  50 , and a rear upper control arm  60 . The axle support  30 , the main control arm  40 , the front upper control arm  50 , and the rear upper control arm  60  are connected to each other. In addition, the main control arm  40 , the front upper control arm  50 , and the rear upper control arm  60  are also connected to the frame  90 . In this way, a multi-link suspension structure may be formed. The multi-link suspension structure can ensure certain comfort, and the wheels  100  are controlled and positioned through the multi-link suspension structure, so that the wheels  100  are perpendicular to the ground as far as possible, a tilt of a vehicle body is reduced to the maximum extent, and ground-sticking performance of the wheels  100  is maintained. The main control arm  40  may play a role of adjusting a toe-in of the wheels  100 , and endures vertical load and left-right unbalance force from the wheels  100 , to improve driving stability of the all-terrain vehicle  2 , and effectively reduce friction of the wheels  100 . The front upper control arm  50  and the rear upper control arm  60  jointly control camber angles of the wheels  100  with the main control arm  40 , and endure cornering force from the wheels  100 . In addition, the main control arm  40  may be a tube member, a steel plate stamping member, or a forged casting member, and the front upper control arm  50  and the rear upper control arm  60  each are of a rod-like structure. In this way, connection and arrangement of the front upper control arm  50  and the rear upper control arm  60  are more facilitated. 
     Specifically, as shown in  FIG.  1    to  FIG.  3   , a mounting base  46  is disposed on the main control arm  40 , and the mounting base  46  may be configured to mount a stabilizer bar  70  and a shock absorber  80 . The main control arm  40  has a first outer end  41 , a first inner end  42 , and a second inner end  43 . The first outer end  41  is rotatably connected to the axle support  30 . The first inner end  42  and the second inner end  43  are connected to the frame  90 . The front upper control arm  50  has a second outer end  51  and a third inner end  52 . The second outer end  51  is rotatably connected to the axle support  30 . The third inner end  52  is connected to the frame  90 . The rear upper control arm  60  has a third outer end  61  and a fourth inner end  62 . The third outer end  61  is rotatably connected to the axle support  30 . The fourth inner end  62  is connected to the frame  90 . In this way, an integral structure of the left rear suspension assembly  10  and the right rear suspension assembly  20  is connected more stably, and can form a multi-link suspension structure together with the frame  90 , thereby improving performance of the left rear suspension assembly  10  and the right rear suspension assembly  20 . 
     As shown in  FIG.  2   , a center connection line between the first inner end  42  and the second inner end  43  is L 1 , a center axis of the first outer end  41  is L 2 , a center connection line between the third inner end  52  and the fourth inner end  62  is L 3 , a center connection line between the second outer end  51  and the third outer end  61  is L 4 , and L 1 , L 2 , L 3 , and L 4  are parallel to each other. It should be noted that, in a moving process of the all-terrain vehicle  2 , the first inner end  42  and the second inner end  43  may move in a direction of L 1 , the third inner end  52  and the fourth inner end  62  may move in a direction of L 3 , the second outer end  51  and the third outer end  61  may move in a direction of L 4 , and the width of the first outer end  41  may change in a direction of L 2 . These movements do not change a positioning characteristic of the wheels  100  since L 1 , L 2 , L 3 , and L 4  are parallel to each other, and the wheel  100  positioning that meets a driving requirement of the all-terrain vehicle  2  can always be maintained. Certainly, a position may be adjusted according to a need for structural arrangement of the rear suspension system  1 . 
     Therefore, the left rear suspension assembly  10  and the right rear suspension assembly  20  may form a multi-link suspension structure. In this way, the all-terrain vehicle  2  may have certain comfort. In addition, the wheels  100  are controlled and positioned through the multi-link suspension structure, so that the wheels  100  are perpendicular to the ground as far as possible, the tilt of the vehicle body is reduced to the maximum extent, and the ground-sticking performance of the wheels  100  is maintained. In addition, L 1 , L 2 , L 3 , and L 4  are parallel to each other, so that the wheel  100  positioning that meets the driving requirement of the all-terrain vehicle  2  can be maintained, to meet suspension comfort and support force required by the all-terrain vehicle  2  in various driving conditions. 
     As shown in  FIG.  1    to  FIG.  3   , the main control arm  40  includes a first rod  44  and a second rod  45 . The first rod  44  is located in front of the second rod  45 , an outer end of the first rod  44  is fixedly connected to an outer end of the second rod  45 , the outer end of the first rod  44  and the outer end of the second rod  45  form the first outer end  41 , an inner end of the first rod  44  is the first inner end  42 , and an inner end of the second rod  45  is the second inner end  43 . In other words, one end of the first rod  44  that is close to the inner side is the first inner end  42 , one end of the second rod  45  that is close to the inner side is the second inner end  43 , and one end of the first rod  44  that is close to the outer side is connected to one end of the second rod  45  that is close to the outer side through the first outer end  41 . Such arrangement is more reasonable. In addition, when the first inner end  42  and the second inner end  43  move in the direction of L 1 , the third inner end  52  and the fourth inner end  62  move in the direction of L 3 , and the second outer end  51  and the third outer end  61  move in the direction of L 4 , the positioning characteristic of the wheels  100  may not be changed, and the wheel  100  positioning that meets the driving requirement of the all-terrain vehicle  2  can always be maintained. 
     Optionally, as shown in  FIG.  1   , the all-terrain vehicle  2  further includes the stabilizer bar  70  and the shock absorbers  80 . Two ends of the stabilizer bar  70  are respectively connected to the main control arm  40  of the left rear suspension assembly  10  and the main control arm  40  of the right rear suspension assembly  20 , and lower ends of the shock absorbers  80  are disposed on the main control arms  40 . The two ends of the stabilizer bar  70  are respectively connected to the main control arm  40  of the left rear suspension assembly  10  and the main control arm  40  of the right rear suspension assembly  20 . In this way, the stabilizer bar  70  may play a role of connection, and the left rear suspension assembly  10  and the right rear suspension assembly  20  are connected to form an integrated rear suspension system  1 . Certainly, the stabilizer bar  70  is disposed in a transverse direction, and the stabilizer bar  70  may improve roll angle stiffness of the rear suspension system  1  and reduce an angle of tilt of the vehicle body of the all-terrain vehicle  2 . The shock absorber  80  includes a spring and a hydraulic damper. An upper end of the shock absorber is connected to the frame  90 , and a lower end of the shock absorber is disposed on the main control arm  40 . When the rear suspension system  1  works, the shock absorber  80  generates a telescopic movement. When the spring is compressed, the spring may absorb impact energy from the ground through the wheels  100 , and the absorbed energy is released when the spring stretches, and the released energy is converted into heat for dissipation by the hydraulic damper. In this way, a shock absorption effect of the rear suspension system  1  can be implemented, thereby improving comfort of a user when driving the all-terrain vehicle  2 . 
     It should be noted that, as shown in  FIG.  1    to  FIG.  3   , the ends of the stabilizer bar  70  and the lower ends of the shock absorbers  80  are disposed on the first rod  44  or the second rod  45 , the ends of the stabilizer bar  70  are disposed adjacent to a midpoint of the first rod  44  or the second rod  45 , and the lower ends of the shock absorbers  80  are disposed adjacent to the first outer ends  41 , to facilitate connection and mounting of the stabilizer bar  70  and the shock absorber  80 . Therefore, the overall structure of the rear suspension system  1  is adapted to the structure of the all-terrain vehicle  2 , and interference between the mounting of the stabilizer bar  70  and the shock absorber  80  and another structure may also be avoided. In addition, the main control arm  40  is not limited to be constructed to have the first rod  44  and the second rod  45 , but may alternatively be constructed to have another reasonable structure. Certainly, the ends of the stabilizer rod  70  and the lower ends of the shock absorbers  80  may alternatively be disposed on the front upper control arm  50 , which may be specifically limited and selected based on an actual situation. 
     In addition, as shown in  FIG.  2   , a vertical plane that passes through a midpoint of a center connection line of the two axle supports  30  is a first reference plane P 1 , and the left rear suspension assembly  10  and the right rear suspension assembly  20  are symmetrically disposed relative to the first reference plane P 1 . The left rear suspension assembly and the right rear suspension assembly have same component structures and same operating principles. The left rear suspension assembly  10  and the right rear suspension assembly  20  are symmetrically disposed relative to the vertical plane of the midpoint of the center connection line of the two axle supports  30 . In this way, the left rear suspension assembly  10  and the right rear suspension assembly  20  may respectively act on the left wheels  100  and the right wheels  100  of the all-terrain vehicle  2 , so that an effect on the left wheels  100  and an effect on the right wheels  100  are the same, and the suspension comfort and a support effect of the all-terrain vehicle  2  are better. 
     Certainly, as shown in  FIG.  2   , the first inner end  42  is located in front of the second inner end  43 , a distance from the first inner end  42  to the first reference plane P 1  is a 1 , a distance from the second inner end  43  to the first reference plane P 1  is a 2 , and a 1  and a 2  meet a relational expression: a 1 &gt;a 2 . The first inner end  42  is located on the front side of the second inner end  43 , and such an arrangement is reasonable. Because a plurality of parts need to be disposed between the first inner ends  42  of the left rear suspension assembly and the right rear suspension assembly, and there is no such requirement between two second inner ends  43 , the distance from the first inner end  42  to the first reference plane P 1  needs to be greater than the distance from the second inner end  43  to the first reference plane P 1 . 
     In addition, as shown in  FIG.  2   , the horizontal plane that passes through the center connection line L 10  of the two axle supports  30  is a second reference plane, the angle between the projection of L 1  on the second reference plane and the projection of the first reference plane P 1  on the second reference plane is a, and a meets a relational expression: 10°≤α≤25°. There is a certain relationship between an angle between L 1  and the first reference plane P 1  and a travel of the wheels  100  of the all-terrain vehicle  2 . The range of the angle between L 1  and the first reference plane P 1  is set to 10≤α≤25°, which is reasonable. When the travel of the wheels  100  of the all-terrain vehicle  2  is small, the angle between L 1  and the first reference plane P 1  needs to be set to be smaller. When the travel of the wheel  100  of the all-terrain vehicle  2  is large, the angle between L 1  and the first reference plane P 1  needs to be set to be larger. In this way, the angle may be better coordinated with the wheels  100 . In addition, the angle between L 1  and the first reference plane P 1  is set to be in an appropriate range, so that a stretching length of the main control arm  40  can be longer, and performance of the main control arm  40  can be better. 
     In addition, as shown in  FIG.  1   , the first inner end  42  is located in a front inner side of the third inner end  52 , and the second inner end  43  is located in a front inner side of the fourth inner end  62 . In this way, the first inner end  42  and the second inner end  43  are closer to the inner side, so that the stretching length of the main control arm  40  is longer, and the performance of the main control arm  40  is better. 
     Specifically, as shown in  FIG.  1    and  FIG.  3   , the axle support  30  may include a main support  31 , an upper mounting part  32 , and a lower mounting part  33 . Both the upper mounting part  32  and the lower mounting part  33  are disposed on the main support  31 , and both the upper mounting part  32  and the lower mounting part  33  protrude inward. The first outer end  41  is connected to the lower mounting part  33 , and the second outer end  51  and the third outer end  61  are connected to the upper mounting part  32 . Both the upper mounting part  32  and the lower mounting part  33  are disposed on the main support  31 . In this way, the main support  31 , the upper mounting part  32 , and the lower mounting part  33  may form an integrated body, to facilitate mounting of the axle support  30 . The first outer end  41  is connected to the lower mounting part  33 , and the second outer end  51  and the third outer end  61  are connected to the upper mounting part  32 . In this way, the main control arm  40 , the front upper control arm  50 , and the rear upper control arm  60  are connected to the axle support  30 , so that structures of the left rear suspension assembly and the right rear suspension assembly are more integrated, and a structure of the first outer end  41  is different from structures of the second outer end  51  and the third outer end  61 . 
     As shown in  FIG.  2   , the all-terrain vehicle may further include a ball joint bearing B 1 , and the outer ends of the main control arm  40 , the front upper control arm  50 , and the rear upper control arm  60  are all connected to the axle support  30  through the ball joint bearing B 1 . The ball joint bearing B 1  may play a role of mounting and connection, and may rotate and sway at any angle during movement. The outer ends of the main control arm  40 , the front upper control arm  50 , and the rear upper control arm  60  are all connected to the axle support  30  through the ball joint bearing B 1 . In this way, the main control arm  40 , the front upper control arm  50 , and the rear upper control arm  60  may move relative to the axle support  30 , these movements do not change a positioning characteristic of the wheels  100 , and the wheel  100  positioning that meets the driving requirement of the all-terrain vehicle  2  can always be maintained. 
     In the description of this application, it should be understood that orientations or positional relationships indicated by the terms such as “center”, “longitudinal”, “transverse”, “length”, “width”, “above”, “under”, “front”, “back”, “left”, “right”, “vertical”, “horizontal”, “top”, “bottom”, “inside”, “outside”, “clockwise”, “counterclockwise”, “axial”, “radial”, and “circumferential”, are orientations or positional relationships shown in the accompanying drawings, and are only intended to facilitate and simplify the description of this disclosure, but are not intended to indicate or imply that an indicated apparatus or component needs to have a specific orientation and be constructed and operated in a specific orientation. Therefore, the terms cannot be construed as a limitation on this disclosure. 
     In the description of this disclosure, “a first feature” and “a second feature” may include one or more of the features. In the description of this disclosure, “a plurality of” means two or more. In the description of this disclosure, that the first feature is “above” or “below” the second feature may include that the first feature and the second feature are in direct contact, or may include that the first feature and the second feature are not in direct contact but are in contact through another feature between the first feature and the second feature. In the description of this disclosure, that the first feature is “on”, “above”, and “over” the second feature includes that the first feature is directly above and diagonally above the second feature, or only indicates that the level of the first feature is higher than that of the second feature. 
     In the description of this specification, with reference to the description of the term, for example, “one embodiment”, “some embodiments”, “exemplary embodiment”, “an example”, “a specific example”, or “some examples”, means that a specific feature, structure, material, or characteristic described with reference to the embodiment or example are included in at least one embodiment or example of this disclosure. In this specification, a schematic description of the foregoing term does not necessarily refer to a same embodiment or example. 
     Although the embodiments of this disclosure have been shown and described, a person of ordinary skill in the art may understand that various changes, modifications, replacements, and variations may be made to these embodiments without departing from principles and objectives of this disclosure, and the scope of this disclosure is limited by the claims and equivalents thereof.