Suspension Systems Employing Laminated Components
Overview of Laminated Suspension Elements
A type of vehicular suspension that utilizes multiple layers of metal (typically steel) or composite material bonded together to act as a single structural unit. These systems provide spring force and damping, crucial for ride comfort and handling.
Construction and Operation
A typical arrangement consists of several strips of metal, called "leaves," stacked on top of each other. These leaves vary in length, with the longest leaf on top and progressively shorter leaves beneath. The stack is typically curved in an arc shape. When a load is applied (e.g., the vehicle encounters a bump), the leaves flex and slide against each other, providing a progressively increasing spring rate. This inter-leaf friction contributes to damping.
Types and Configurations
- Multi-Leaf: Features several individual leaves. This configuration provides a high load capacity and allows for customization of the spring rate through the selection of leaf thickness, length, and number.
- Mono-Leaf: Consists of a single, often tapered, leaf. Offers weight savings compared to multi-leaf designs, but generally has a lower load capacity. Often made of composite materials.
- Full Elliptic: An older design where two semi-elliptic springs are mounted end-to-end, forming an ellipse. Inefficient and now rarely used.
- Semi-Elliptic: The most common configuration, where half of an elliptical shape is used. One end is attached to the vehicle frame and the other to the axle.
- Parabolic: A variant of the multi-leaf design with fewer, thicker leaves that are tapered to reduce weight and inter-leaf friction.
Materials and Manufacturing
Traditionally made from high-strength spring steel alloys, with individual leaves heat-treated and formed to specific profiles. Modern designs increasingly incorporate composite materials such as fiberglass or carbon fiber reinforced polymers for reduced weight and improved fatigue resistance. Manufacturing processes include hot rolling, cold forming, shot peening, and bonding techniques.
Advantages and Disadvantages
Advantages:
- Simple design and robust construction.
- High load carrying capacity.
- Relatively inexpensive to manufacture.
- Provides both spring and damping functions.
Disadvantages:
- Higher weight compared to other suspension types.
- Inter-leaf friction can lead to wear and noise.
- Spring rate is not easily adjustable.
- Can transmit vibrations and road noise to the vehicle.
Applications
Commonly found in heavy-duty vehicles such as trucks, vans, and SUVs, particularly in rear suspensions where high load capacity is required. Also used in some agricultural and industrial equipment.