what is difference between parabolic or elliptical leaf springs
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Greetings All,
As Some May Know Of My Suspension Woes, I Just Found This, And I'm Wondering Why We Aren't All Running Parabolic Leafs?
What is a parabolic spring? A parabolic spring, in very basic terms, is a leaf spring that has a different design than a standard leaf spring. The changes in its shape allow forces applied to it, to change the shape easier than with a standard leaf spring. The parabolic spring, or spring pack, are tapered in a parabolic way rather than in a linear way, as stock leaf springs are. This means that they are thick in the middle (under the axle) and they taper in a parabolic manner towards the ends (near the shackles). The tapering steps down in a parabolic manner, i.e. Y=Xsquare + n where Y and X are related to the thickness and the length of the leaf. The shape of the spring is also parabolical. This design keeps the spring flexible, but able to carry the load of the vehicle. The reason why these springs are able to offer a smoother ride and more axle articulation with no downside is that of this parabolic design and the lack of interleaf friction.
Think of a stock leaf spring as an arch that is made from one size of material from end to end. An arch is a very strong and rigid structure, able to support a lot of weight, but the arch is very hard to break. It takes a huge force to flex the arch. This is why stock leaf springs ride very hard. When a force is applied to the arch (by saying hitting a bump with your axle) the force needed to flex the arch is great, so instead of flexing, the spring stays rigid and the bump (or force) is sent through the suspension into the Rover, and then into your lower back!
Think of a parabolic spring as an arch that has a taper from the middle to each end. It retains the load carrying ability but when these huge forces are applied (by hitting a bump or twisting the suspension off road) the parabolic design allows the spring to give a little and reduces shock to the vehicle and the driver. In an off-road situation, this means that both compression and extension can be greatly improved as this design works well in both directions.
The parabolic design is also better able to handle the force distribution from the vehicle to the axle. The parabolic spring is linear in the rate while a stock leaf springs are degressive in rate, meaning it can offer load carrying with fewer leaves, where standard leaf spring can not.
The parabolic spring design, having fewer leaves, means that interleaf friction is drastically reduced as compared to a standard leaf pack of 7 or more leaves. This allows the spring to compress or extend easier as this friction (resistance) does not need to be overcome to achieve flex; therefore, the ride is more comfortable and off road, articulation is improved. This also reduces rust in the parabolic spring pack, a major cause of standard leaf spring failure.
As the springs cut down on forces sent into the vehicle, they will actually reduce the noise levels as well! The design of the spring also reduces unsprung weight.(ECR 2013)
As Some May Know Of My Suspension Woes, I Just Found This, And I'm Wondering Why We Aren't All Running Parabolic Leafs?
What is a parabolic spring? A parabolic spring, in very basic terms, is a leaf spring that has a different design than a standard leaf spring. The changes in its shape allow forces applied to it, to change the shape easier than with a standard leaf spring. The parabolic spring, or spring pack, are tapered in a parabolic way rather than in a linear way, as stock leaf springs are. This means that they are thick in the middle (under the axle) and they taper in a parabolic manner towards the ends (near the shackles). The tapering steps down in a parabolic manner, i.e. Y=Xsquare + n where Y and X are related to the thickness and the length of the leaf. The shape of the spring is also parabolical. This design keeps the spring flexible, but able to carry the load of the vehicle. The reason why these springs are able to offer a smoother ride and more axle articulation with no downside is that of this parabolic design and the lack of interleaf friction.
Think of a stock leaf spring as an arch that is made from one size of material from end to end. An arch is a very strong and rigid structure, able to support a lot of weight, but the arch is very hard to break. It takes a huge force to flex the arch. This is why stock leaf springs ride very hard. When a force is applied to the arch (by saying hitting a bump with your axle) the force needed to flex the arch is great, so instead of flexing, the spring stays rigid and the bump (or force) is sent through the suspension into the Rover, and then into your lower back!
Think of a parabolic spring as an arch that has a taper from the middle to each end. It retains the load carrying ability but when these huge forces are applied (by hitting a bump or twisting the suspension off road) the parabolic design allows the spring to give a little and reduces shock to the vehicle and the driver. In an off-road situation, this means that both compression and extension can be greatly improved as this design works well in both directions.
The parabolic design is also better able to handle the force distribution from the vehicle to the axle. The parabolic spring is linear in the rate while a stock leaf springs are degressive in rate, meaning it can offer load carrying with fewer leaves, where standard leaf spring can not.
The parabolic spring design, having fewer leaves, means that interleaf friction is drastically reduced as compared to a standard leaf pack of 7 or more leaves. This allows the spring to compress or extend easier as this friction (resistance) does not need to be overcome to achieve flex; therefore, the ride is more comfortable and off road, articulation is improved. This also reduces rust in the parabolic spring pack, a major cause of standard leaf spring failure.
As the springs cut down on forces sent into the vehicle, they will actually reduce the noise levels as well! The design of the spring also reduces unsprung weight.(ECR 2013)
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A parabolic spring, in very basic terms is a leaf spring that has a different design than a standard leaf spring. The changes in its shape allow forces applied to it, to change the shape easier than with a standard leaf spring. The parabolic spring, or spring pack, are tapered in a parabolic way rather than in a linear way, as stock leaf springs are. This means that they are thick in the middle (under the axle) and they taper in a parabolic manner towards the ends (near the shackles). The tapering steps down in a parabolic manner, i.e. Y=Xsquare + n where Y and X are related to the thickness and the length of the leaf. The shape of the spring is also parabolical. This design keeps the spring flexible, but able to carry the load of the vehicle. The reason why these springs are able to offer a smoother ride, and more axle articulation with no down side is because of this parabolic design and the lack of interleaf friction.
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