The Advantages of Using Conical Springs
What is the advantage or benefit of using a conical spring?
Conical springs are basically compression springs coiled in increasing or decreasing outer diameters thus making its shape a cone or tapered one. These springs tend to reduce solid height and provide stability.
Conical springs are also known as tapered springs or cone springs. One of the advantages about tapered springs is that they provide stability to those sprigs that have a large slenderness ratio. The slenderness ratio defines whether a spring will bend or buckle during compression/deflection. A high slenderness ratio means that the compression spring’s free length is more than 4 times larger in comparison to the outer diameter. In other words, it has a 4 to 1 ratio. Its length is too long in proportion with its outer diameter and this, by laws of physics, will cause the spring to deform when it travels down to a desired solid height. Now let’s move on to the other benefit about conical compression springs; the reduction of the solid height.
Due to it’s tapered cone shape, some cone springs have the diameters adjusted to a point where they’ll perform a telescope effect when deflecting. The way to do this is by making sure that the inner diameter into which the next coil will compress into is larger than the next coil’s outer diameter. This will cause the smaller coil’s outer diameter to compress into the larger coil’s inner diameter. If the spring has enough elasticity to compress to solid height, your spring’s solid height will be the size of the wire diameter since it will compress down to the last coil. If you don’t need such a small solid height, the smaller coil’s outer diameter doesn’t necessarily have to be smaller than the larger coil’s inner diameter since we are using round wire. As you can see from the image to the right, the round wire still allows some telescope effect, giving you more travel space and a smaller solid height. This reduces the solid height as well but it will not produce a full telescope effect where the solid height equals your wire diameter.
In terms of load and rate, conical springs are non-linear springs. Non-linear springs are springs which do not have a constant rate. In our product lists, we provide you with an average spring rate which is only estimated. The reason these springs are non-linear is because of the variation in the outer diameter. As shown in our force chart, a smaller outer diameter gives you more force and a larger diameter gives you less force so, since conical springs have different diameters throughout their bodies, the force is non-linear.
Another reason to why the rate of the springs is an average involves the manufacturing of the spring. Throughout the manufacturing process, the angle of taper may change since the diameters of the active coils between the smallest and largest end coils are a variable. The only fixed measurements are those of the large and small outer diameters on the ends. The angle of the taper will dictate the active coil diameters going from the small outer diameter end to the large outer diameter end. This is why conical springs have a non-linear rate; because of the variation in the active coils’ diameters coupled with the angle of taper.