Design equations for hair springs and brush springs. This spring has a 5 length inside hooks, a spring rate of 5 lbf. The compression spring design example discussed above is a typical one to show the approach of solving the helical compression spring related problems. For a spring with recommended wire diameters, the t pitch between spring threads in free state should be within the 0. Torque can be converted to load by the formula given below.
The spring acts on the outer ring of one of the two bearings. The helical compression spring calculations typically use five spring equations discussed in this article. Ramp up preload over a finite time and then hold load steady. Extension springs are springs which absorb and store energy by offering. Generally, the purchaser of a compression spring does not specify. This outer ring must be able to be axially displaced. Operating clearance of a bearing can be calculated from initial bearing internal clearance decrease in internal clearance due to interference and decrease in internal clearance due to difference in temperature of the inner and outer rings. One of the most critical factors when it comes to reliability of a threadedfastener joint is preloadthe. Handbook for disc springs industrial and bearing supplies. An online compression spring design calculator is also available over the web. If the turntotension procedure is used to establish clamping load, it is necessary to know both the spring rate of the bolt and the spring rate of the clamped components, since turning the bolt stretches the fastener and compresses the parts being clamped. Torsion springs exert a torque when they are twisted or deflected. Guidance is provided for general bolted joint design, computation of preload uncertainty and preload loss, and the calculation of the bolted joint factor of safety.
Preload is very useful when installing your coil spring into your mechanism or application. Modeling the effects of bolt preload machine design. Spring preload calculations quality spring, affordable prices. Preload is a measurement of how much a spring is compressed at full extension of the shock. Preload is recommended to compress the first coils at each. Compression spring calculation formulas in metric units. This paper shortly describes stress concentration factor for helical springs on the. The simplest method of applying preload is to use a wave spring. Commonly asked questions like, whats the difference between spring rate and preload. The preload force remains practically constant, even when there is axial displacement of the bearing as a result of thermal elongation. Technical data fc11 2 spring calculations excerpts from. After preload is set, you can set the length of the coilover assembly to set the ride height.
Thread the upper spring adjuster down until it just touches the spring, you are now at 0. Symbols used in spring design formulae are shown in table 1. Congratulations on correctly setting the spring preload. Initial tension, types of ends and dimensions, design equations, choice of operating stress for static and cyclic. Formula for change of load due to differential thermal expansion.
Spring design calculation within the spring design, wire diameter, number of coils, and spring free length l0 are designed for a specific load, material and assembly dimensions, or spring diameter. Keep in mind that the load or preload put onto a progressive. Once you have set the preload and locked the spring perches together, it is time to set the ride height by adjusting the shock length. Assembling this type of spring requires initial preload of the. Pdf a study of the preload force in metalelastomer torsion. Calculating the proper preload for threaded fasteners. Axial loads, shear loads, thermal loads, and thread tear out are used in factor of safety calculations.
947 686 821 668 760 411 1318 1494 109 1395 387 158 228 182 771 865 1209 584 661 1197 172 435 381 1531 1491 226 765 836 1487 650 570 238 1455 840 1185 934 875 984