TOP TIPS FOR DESIGNING WITH FLAT WIRE SNAP RINGS
In order to reduce assembly cost and complexity, design engineers are often tasked with simplifying application designs. One area that has proven to provide opportunities for design simplification and cost reduction are fasteners and fastening methods. Trends in recent years have been away from threaded fasteners and in favor of circlips or snap rings, which are precision metal fasteners that are installed into a groove on a shaft or in a housing or bore creating a shoulder that retains an assembly. They eliminate threading, tapping, drilling and other machining operations associated with more traditional fasteners like screws, nuts, bolts, cotter pins, washers and more.
Tip 1. Consider the benefits of providing more radial clearance.
Constant section snap rings and spiral rings are ideal where more assembly clearance is needed. These flat wire snap rings are manufactured with a constant radial width and do not have extended lugs providing for more radial clearance on a shaft or in a bore.
Tip 2. Consider snap rings with the most design flexibility.
Constant section snap rings and spiral rings offer the most design flexibility and customization options. Material thickness, width, and ring diameter are all easily changed. Since minimal tooling is required, lower production volumes are available for new designs. Depending on the application, constant section snap rings are more economical than tapered section rings. Also, be sure that a wide selection of sizes are available, such as those offered by Rotor Clip that range from 0.39-inch to 39.37-inches (10mm to 1000mm) for constant section snap rings and .188-inch to 25-inches (3mm to 635mm) for spiral rings.
3. Make the right material selection.
Work with a company that provides a wide range of materials to choose from for specific application environments. For example, a company such as Rotor Clip offers materials such as carbon spring steel, various stainless steel grades, and specialty alloys such as beryllium copper, phosphor bronze, as well as Hastelloy, A286, and Inconel X750 which are only available for flat wire snap rings.
4. Counter negative effects of high RPMs with specialized spiral rings.
Centrifugal forces and unbalance are just two contributing factors to NVH in an application caused by high RPMs. Multi-turn spiral rings can be produced with an additional locking tab that prevents the ring from “opening up” during high RPMs and unseating from the groove on shaft. Theoretically, these rings cannot dislodge from the groove due to the centrifugal forces caused by high RPMs. Also available are spiral rings with a balanced geometry. These rings feature punch-outs along the ring’s rim allowing it to spin on a shaft without adding additional wobble. A third, specialized, spiral ring option used in rotating applications is reverse-wound spiral rings. These type of rings are coiled in the opposite direction and are beneficial in applications where relative rotation poses a risk to catching on a ring end or unwinding the ring altogether.
5. Avoid grinding costs with select fit flat wire snap rings.
Traditionally, select fit rings for endplay take-up are produced by grinding standard rings down to the individual thicknesses specified by the customer. However this extra process and the associated cost can be eliminated by specifying constant section snap rings that are manufactured from precision rolled wire with a 0.001-inches (0.025mm) total tolerance. These rings can be produced in graduations and thickness tolerances between 0.02mm and 0 .05mm to rigidly reduce endplay in steps.
6. Select flat wire rings to minimize wear on mating parts.
Unlike stamped circlips, flat wire rings can be produced with a defined edge radius. The final ring has no sharp corners that could mar or cause wear on mating parts during installation or removal of the ring, or under normal operating conditions.
7. Choose the right packaging for your manufacturing needs.
Be sure to know how your manufacturing process will be using the snap rings so that you can select the best packaging, whether it is plastic shrink wrapped or bulk. For example, end users with high volume part usage and installation needs most often use shrink wrapped and stacked parts to feed their automated assembly equipment.
8. There are constant section snap rings specifically designed for retaining SAE standard metric bearings.
Manufactures, such as Rotor Clip, produce constant section snap rings that are specifically designed to work with standard SAE metric bearings. One example is the HBL / HBM / HBH series of internal, metric constant section snap rings. These rings range in size from 30mm to 200mm and specific light, medium, and heavy bearings are associated by bearing number with the particular part number of this ring series. There are also external, metric constant section ring lines designed for use with bearings such as SR (for grooves in outer tracks of ball or roller bearings), SB, and CBS (DIN 5417).
9. Work with a partner that offers technical and design experience over a wide industry base.
Every application is different, so if you have questions about the parameters of your application that might cause challenges—like operating conditions, installation requirements, anticipated loads, axial endplay, or space constraints—you’ll want to select a company with such design engineering knowledge. Rotor Clip, for instance, provides fast-response engineering support services in several ways—tailored to customer needs. They are available for live, online web-conferencing; face-to-face meetings at your location; and phone or email correspondence for quick answers. Check out their capabilities here.
