Fatigue testing for life of clutch springs pdf

Don't design just within the Goodman diagram without being aware of all of these other factors. When cycle testing springs, it is always best to cycle test in the application. When this is not possible, care must be taken to duplicate the application as closely as possible. This includes the type of motion and the speed, as well as, fixturing and lubrication, etc. One common misconception is that we can test 20 springs to 10,, cycles and determine that we have verified the design, and we can be assured that we won't have any fatigue problems in the future.

Nothing could be further from the truth. Rockford Spring Company can work with you in determining appropriate test criterion. It is not unusual to have a complaint of a broken spring either in the field or in a cycle test and be told, "We have never had any failures before". The truth is, they may have just been lucky before. If you only know that the springs haven't failed, but you don't know how much safety factor you have, you are just counting on luck.

An even more elaborate test process is to do a Weibull analysis. A Weibull analysis is considerably more expensive than a simple cycle test because it involves testing to failure at several different stress levels. This type of analysis can be done to actually predict the probability of failures at different stress levels and numbers of cycles.

This can be used to test an existing design or to design to an acceptable probability of failure on a new design. Obviously, a single test of 20 pieces at the same stress as the application does not guarantee a very low probability of failure. Contact our Engineers for help with your specific application. Sales Rep Locator Select State. Call us at Request a Quote.

Interpreting the Goodman diagram : To interpret a Goodman diagram we need to understand several things. Cycle testing : When cycle testing springs, it is always best to cycle test in the application.

Improving fatigue life : There are several methods that can be used for improving fatigue life. Lower stress : The most obvious way to improve fatigue life is to design a spring with a lower stress.

Rockford Spring can help in this regard. If room permits, we can design with a larger wire diameter or lower final load. Unfortunately, sometimes the only way to reduce the stresses is to allow more room for the spring. This is much easier to do in the early design stage. Contact us early in the process to make sure we are allowing enough space to design a spring that will have a robust design. Shotpeen : Shotpeening can greatly improve the fatigue life of springs.

Inertia dynamometers can be adapted for testing of automatic transmission, manual clutch, or differential systems. Vehicle testing can be performed on the 4]roll chassis dynamometer at the ARC facility in Canton, Michigan or at proving ground facilities located in Michigan, Ohio and Arizona.

Driveline System Your most recent searches Delete. Frequent searches. Other sections. Catalog excerpts. Open the catalog to page 2. Open the catalog to page 3. Open the catalog to page 4. Biaxial Wheel Durability Testing 1 Pages. Biaxial Wheel Tester Model 1 Pages. Rotor Mapping Station Model 2 Pages. Four Roll Chassis Dynamometer 2 Pages.