Introduction for the types of Automobile Chassis Bushings and their NVH Functions

Subframe Bushing, Body Bushing (Suspension)

1. Installed between the subframe and the body to play a secondary vibration isolation role, typically used in horizontal powertrain arrangement;

2.Supporting suspension and powertrain loads supporting suspension and powertrain loads, isolating vibration and noise from the subframe Isolating vibration and noise from the subframe;

3.Auxiliary functions: withstand powertrain torque, powertrain static support, withstand steering, suspension loads, isolate engine and road excitation

Design Principles

1.Isolation frequency or dynamic stiffness, damping coefficient

2.Static Load and Range Static Load and Range, Limit Deformation Requirements Ultimate Deformation Requirements

3.Dynamic load (regular use), maximum dynamic load (severe conditions)

4.Collision requirements, constraints and loads, space constraints, desired and required assembly requirements;

5.Mounting method (including bolt size, type, orientation and anti-rotation requirements, etc.)

6.Suspension position (high admittance area, insensitive);

7.Corrosion resistance requirements, temperature range of use, other chemical requirements, etc.;

8.Fatigue life requirements, known important characteristic requirements (dimensions and functions);

9.Price target

Assembly method

1.Above part is Load-bearing padding

2.Below part is Rebound padding

3.Upper Metal Bulkhead: *Support Load-bearing Pad Expansion* to Control Assembly height:

1) Vehicle load and suspension stiffness control body load height Vehicle load and suspension stiffness control body load height

2) The lower pad controls the body Rebound displacement;

3) The lower pad is always under pressure Second, the subframe bushing, the body bushing (suspension)

Suspension bushing

Application:

1.Used in suspension systems to provide torsional and tilt flexibility, and for axial and radial displacement control;

2.Low axial stiffness for good vibration isolation while soft radial stiffness for better stability;

(1) Construction Type: Mechanically Bonded Bushings

– Applications: Leaf Springs, Shock Absorber Bushings, Stability Rod tie rod;

– Advantages: cheap, do not need to pay attention to the problem of bonding strength;

– Disadvantages: the axial direction is easy to come out, and the stiffness is difficult to adjust.

(2) Construction Type: Single Side Bonded Bushings

Applications: Shock absorber bushings, suspension tie rods and control arms

– Advantages: Inexpensive compared to normal double-sided bonded bushings, the bushing always rotates to the neutral position

– Disadvantage: The axial direction is easy to come out. In order to ensure the pressing force, must have the flash design

(3) Construction Type: Double Side Bonded Bushing

Applications: Shock absorber bushings, suspension tie rods and control arms

– Advantages: better fatigue performance compared to unilateral bonding and mechanical bonding, and the stiffness is easier to adjust;

– Disadvantages: But the price is also more expensive than single-sided bonding and double-sided bonding.

(4) Construction Type: Double Side Bonded Bushing - Damping Hole Type

Application: Control arms, trailing arm bushings

– Advantage: stiffness is easily adjustable

– Disadvantages: Potential failure mode of orifice under torsional forces (> +/- 15 deg); locating features required for pressure fit, will add expense

(5) Construction Type: Double Sided Bonded Bushings - Spherical Inner Tube

Application: control arm;

– Advantages: low cone pendulum rigidity, low cone pendulum rigidity and large radial rigidity; large radial rigidity;

– Disadvantages: Expensive compared to ordinary double-sided bonded bushings

(6) Construction Type: Double Sided Bonded Bushing - with Stiffness Adjustment Plate

Application: control arm;

–Advantages: The ratio of radial to axial stiffness can be increased from 5-10:1 to 15-20:1, the radial stiffness requirement can be met with lower rubber hardness, and the torsional stiffness can also be controlled;

– Disadvantages: Compared with ordinary double-sided bonded bushings, it is expensive, and when the diameter is reduced, the tensile stress between the inner tube and the stiffness adjustment plate cannot be released, resulting in problems with fatigue strength.

Stabilizer bar bushing

Stabilizer bar:

1. As part of the suspension, the stabilizer bar provides torsional rigidity when the car turns sharply to avoid excessive yaw of the car;

2. Both ends of the stabilizer bar are connected to the suspension through the stabilizer bar tie rods (such as control arm) connected;

3. At the same time, the middle part is connected to the frame with a rubber bushing for stability

The function of the rod bushing

1. The function of the stabilizer bar bushing as a bearing connects the stabilizer bar tie rod with the frame;

2. Provides additional torsional stiffness for the stabilizer bar tie rod;

3. At the same time, prevents displacement in the axial direction;

4. Low temperature Abnormal noise must be avoided.

Differential bushing

The function of differential bushing

For four-wheel drive engines, the differential is generally connected to the body through a bushing to reduce torsional vibration

System objectives:

20~1000Hz vibration isolation rate
rigid body mode (Roll, Bounce, Pitch)
control due to temperature Stiffness fluctuations caused by changes

Hydraulic bushing

Structural principle:

1. In the direction of hydraulic damping, two liquid chambers filled with liquid are connected by a relatively long and narrow channel (called inertial channel);

2. Under the excitation in the hydraulic direction, the liquid will resonate and the volume stiffness will be amplified, resulting in a higher damping peak value.

Application:

1. Control the radial damping direction of the arm bushing;

2. The axial damping direction of the pull rod; the axial damping direction of the pull rod;

3. Control arm radial damping direction but vertical installation;

4. The subframe bushing is damped in the radial direction but installed vertically the subframe bushing is damped in the radial direction but installed vertically

5. The torsion beam is installed obliquely in the radial damping direction;

6. Supported on the pillar, installed vertically in the axial damping direction

7. Attenuate the Judder excitation caused by the unbalanced force of the front wheel brake

8. Attenuate the radial and lateral vibration modes of the subframe, and the damping direction is the radial direction.

9. Rear torsion beam hydraulic bushing is used to suppress the excitation when the vehicle is driving on rough roads, while ensuring toe correction.

10. The hydraulic strut is supported on the upper side, which is used to control the 10~17Hz Hop mode of the wheel, and its dynamic characteristics are independent of the tube shock absorber.


Post time: Jul-09-2022