Chassis Bushing Design: Tuning Rubber Stiffness and Hydraulic Bushings
Three Functions
- Connect two relatively moving parts
- Absorb road and powertrain vibration
- Constrain motion direction and control geometry
Setting Rubber Hardness
Shore hardness (typically 50-80 A) sets stiffness:
- Soft: Better isolation and comfort, less precision
- Hard: Precise and durable, more vibration
- Structure (holes, fabric, inserts) makes one axis soft and another stiff
Hydraulic Bushings
- Internal fluid chambers and throttling passages
- Low-frequency, high-amplitude motion damps vibration strongly
- Used on subframes and large lower-arm bushings
- Complex and costly
Trade-offs
- Comfort first - soft rubber or hydraulic
- Handling first - hard or inserted bushings
- Cost sensitive - plain rubber
- Final matching via CAE and road tuning
Huami
Huami builds bushings to OE hardness and structure.