REAR SUSPENSION SYSTEM GENERAL


  1. OUTLINE


    1. A torsion-beam type suspension is used, in which an axle beam with a U-shaped cross section is located in the middle of the trailing arm, for the rear.

    2. A rear axle carrier bush is obliquely mounted to obtain a toe-correct function, thus providing excellent driving stability and ride comfort.

    3. The suspension layout has been optimized to make the vehicle floor low and flat, thus providing sufficient space in the rear compartment.

      A0116NJE03
      Text in Illustration
      *A for Drum Brake *B for Disc Brake
      *1 Rear Shock Absorber Assembly *2 Rear Coil Spring
      *3 Axle Beam (Rear Axle Beam Assembly) *4 Rear Axle Carrier Bush
      *5 Trailing Arm (Rear Axle Beam Assembly) - -

  2. MAIN FEATURES


    1. Toe and Camber Change


      1. In a torsion-beam type suspension, the camber angle and the toe change differ between the bouncing case and the tramping case, offering both straight-line stability and excellent cornering stability.

      2. Bouncing Case: Similar to the full-trailing arm type suspension, the axis that joins the center of the right and left bushings in the trailing arms is the center of the movement.

      3. Tramping Case: During tramping, or if a difference in suspension travel is created between the right and left wheels, the axle beam twists with its shearing center as the center of its rotation. Also, camber changes in relation to the suspension travel are determined by the ratio of the distance between the bushing in the trailing arm, the axle center and the shearing center ("α" in the figure below) and distance between the bushing in the trailing arm and the axle center ("L" in the figure below). Consequently, through the optimal allocation of the axle beam, the changes in the camber angle in relation to the suspension travel have been optimized, thus ensuring excellent cornering performance.

        A0116E9E11
        Text in Illustration
        *a Bound *b Rebound
        *c Instantaneous Rotational Axis of Right Axle *d Center of Bushing
        *e Shearing Center *f Camber Change Rate α/L

    2. Anti-lift Geometry


      1. The lifting of the rear end of the vehicle during braking occurs due to the shifting of the center of gravity caused by inertia. The intersecting point (OR) supports the braking force (BF), and generates a force (BF1) in the direction of the intersecting point (OR) and a component force (BF2) in the direction of the ground contact. The force (BF1) can change the height of the intersecting point (OR). When the intersecting point (OR) is set high, it acts in the opposite direction (-▲W) of the load fluctuation (W) in order to restrain the lift.

        A0116OVE01

    3. Toe-correct Function


      1. The longitudinal and lateral forces that are created in the vehicle during cornering cause the bushings in the trailing arms to deform. On a right turn, the right trailing arm moves forward and the left trailing arm moves rearward, creating a tendency for the left wheel to toe out. In this situation, the bushings that are installed in the trailing arms are designed to utilize the lateral force, which is applied to the bushings during cornering, to correct the left trailing arm towards the toe-in direction.

        A0116CNE02
        Text in Illustration
        *A Without Toe-correct Function *B With Toe-correct Function
        *1 Bushing *2 Left-side Wheel
        *a Lateral Force *b Lengthwise Force
        *c Lateral Force Applied to the Bushing *d Bushing Movement