FD120-20 Contitech Double Convoluted Style Air Spring 77-270mm Lift Axle Air Bags

FD120-20 Contitech Double Convoluted Style Air Spring 77-270mm Lift Axle Air Bags
 
Product Description

FD 120-20 Rubber Air Spring Technical Data

Top cover plate diameter: 141mm
Bottom cover plate diameter: 141mm
Threaded holes: M8X15mm

Center distance between threaded holes:70mm
Air hole specifications:G1/4,G3/4
Maximum outer diameter of bladder: 218mm
Maximum height: 270mm
Minimum height: 77mm
Compressed height: 193mm

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Double Convoluted Air Spring For Lift Axle

A Double Convoluted Air Spring is a specific type of air spring commonly used as the lifting mechanism for lift axles on trucks and trailers. Here's a breakdown of why it's well-suited for this application:

1.What is a Lift Axle?
An axle that can be mechanically raised off the road surface when not needed (e.g., when the vehicle is unladen or partially laden).
Purpose:To reduce tire wear, improve fuel efficiency, decrease wear on roads, and comply with axle weight regulations by only deploying the axle when the load requires the extra capacity.

2. Why is a Double Convoluted Spring Ideal for Lift Axles?

High Lift Capability: The long stroke is the primary reason. Lift axles need to retract completely, raising the tires high off the ground to avoid contact. Double convoluted springs excel at providing the necessary vertical travel to achieve this significant lift height.

Sufficient Load Capacity: While prioritizing lift height, they still provide sufficient air volume and pressure capacity to support the axle's share of the load effectively when lowered and inflated.

Reliable Deployment: When air pressure is applied, the spring extends predictably and forcefully to lower the axle smoothly onto the road surface.

Compactness: The design allows the necessary stroke within the spatial constraints around the axle and suspension components, especially when retracted.

Articulation: Provides the flexibility needed as the suspension moves over uneven terrain when the axle is lowered and loaded.

Durability (in this context): While they have more exposed rubber than sleeve springs, the intermittent use of a lift axle (spending much of its time retracted and unpressurized) generally means the double convoluted design offers sufficient lifespan for this specific application. The benefits of high lift outweigh potential wear concerns.

3. How it Works in a Lift Axle System?

1. Lifting (Axle Retracted): Air is exhausted from the spring(s). The spring collapses to its minimum height under the weight of the axle assembly. The double convolution design allows it to compress down significantly, pulling the axle and tires up high off the road.

2. Lowering (Axle Deployed): Compressed air is supplied to the spring(s). The spring inflates, extending its height. The long stroke of the double convoluted spring pushes the axle assembly downward forcefully until the tires contact the road and the spring reaches the pressure needed to support its share of the vehicle's load.