REAR SUSPENSION SYSTEM


  1. OUTLINE


    1. A torsion-beam type suspension is used.

    2. Through the optimal specification of components, the rear suspension offers excellent riding comfort and stability.

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

    4. For GRMN, a special suspension that decreases the vehicle height by 10 mm (0.39 in.), compared to that of the standard models, is used. The constant values of the front coil spring have been revised and the damping force of the front shock absorber assembly has been tuned to optimize the rolling posture during cornering, thus delivering excellent vehicle maneuverability and stability.

      B0041KIC01
      *A For Drum Brake *B For Disc Brake
      *1 Rear Suspension Support *2 Rear Coil Spring
      *3 Rear Shock Absorber Assembly *4 Axle Beam (Rear Axle Beam Assembly)
      *5 Trailing Arm (Rear Axle Beam Assembly) *6 Rear Axle Carrier Bush
      *a The illustrations shown are examples only. - -

    5. For GRMN, the floor panel brace RH (front floor panel brace), floor panel brace LH (rear floor panel brace), and front center floor brace are additionally provided to the installation portion of the trailing arm (rear axle beam assembly) to suppress body torsion, thus enhancing high vehicle maneuverability and stability.

      Figure 1. for GRMN

      B0041I1C02
      *1 Front Center Floor Brace *2 Floor Panel Brace RH (Front Floor Panel Brace)
      *3 Floor Panel Brace LH (Rear Floor Panel Brace) - -

      Note

      Be sure to use the jack-up points that are provided on the body when raising the vehicle on the jack. Never apply a jack under the axle beam (rear axle beam assembly), spring seat, trailing arm (rear axle beam assembly), or bushing of the rear suspension.

  2. MAIN FEATURES


    1. 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. The same as the full-trailing arm type suspension, the axis that joins the center of the right and left bushings in the trailing arms (rear axle beam assembly) is the center of movement during any same direction travel.

      3. During opposite direction travel, or if any difference in the suspension travel is created between the right and left wheels, the axle beam (rear axle beam assembly) 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 (rear axle beam assembly), the axle center and the shearing center ("α" in the figure below) and distance between the bushing in the trailing arm (rear axle beam assembly) and the axle center ("L" in the figure below). Consequently, through the optimal allocation of the axle beam (rear axle beam assembly), the changes in the camber angle in relation to the suspension travel have been optimized, thus ensuring excellent cornering performance.

        B0041IWE05
        Text in Illustration
        *a Bound *b Rebound
        *c Shearing Center *d Center of Bushing
        *e Instantaneous Rotational Axis of Right Axle *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.

        B0041HXE02
        *1 OR

    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 (rear axle beam assembly) to deform. On a right turn, the right trailing arm (rear axle beam assembly) moves forward and the left trailing arm (rear axle beam assembly) moves rearward, creating a tendency for the left wheel to toe-out. In this situation, the bushings that are installed in the trailing arms (rear axle beam assembly) are designed to utilize the lateral force, which is applied to the bushings during cornering, to correct the left trailing arm (rear axle beam assembly) towards the toe-in direction.

        B0041IME09
        Text in Illustration
        *A Without Toe-correct Function *B With Toe-correct Function
        *1 Bushing *2 Left Wheel
        B0041GB Bushing Movement B0041G0 Lateral Force
        B004197 Lengthwise Force B004173 Lateral Force Applied to the Bushing