Learn if rubber might be your best solution for components in critical applications

Robinson Rubber Products, a designer, developer and manufacturer of custom-molded rubber products, extruded rubber products and precision rollers, has several new capabilities to bond molded rubber components to your parts to deliver superior performance. Bonding rubber to your part can also eliminate secondary operations and extra components, plus reduce weight and costs. Robinson Rubber announces it has designed and manufactured a coupling device that helps RV generators deliver significantly improved performance. A prominent manufacturer of electrical generator sets for recreational vehicles was redesigning their product platform, pushing the envelope for higher power, quieter function, and greater efficiency, all in a smaller package. The old technology of using a fabric-reinforced rubber drive belt to connect the gasoline engine to the generator flywheel was no longer working and a new approach was needed. The higher peak loads in their new more powerful engine design were shredding the existing belt technology, turning a 10-year generator service life into a few hours! The Engineering team decided they needed to soften the peak loads of the pistons so the belt could survive, and a rubber coupling device seemed like a good solution. However, the new genset was scheduled to launch soon and there was no budget to solve this problem. Complicating the situation further, such a device would need to fit within a very tight space requirement, and it would have to have to tolerate high heat, ozone and vibration.

After calling in two leading rubber component manufacturers and wasting precious days, the manufacturer found that both firms proposed custom solutions with a component cost of $15- $20 each, and that their timelines had prototype and production development taking months. The purchasing agent of the generator manufacturer suggested the Engineering team turn to Robinson Rubber for a solution. Years of experience told him this should be a $5 part, not a $20 one. That, plus Robinson Rubber had been a trusted supplier for several of their other rubber components since 1954.

The Engineering team agreed and work started immediately on prototypes. But it was not just a matter of Robinson Rubber meeting a bunch of documented physical specifications and sizes; the drive coupling needed to be dynamically balanced, analyzed and tuned to mate with the dynamic drive characteristics of the generator. It required damping character in order to smooth out the explosive impulse of the engine, but without excessive energy absorption that might lead to extreme internal heating of the rubber, that could cause it to self-destruct. Also, the device’s natural frequency needed to be tuned far enough away from that of the engine so they cancel each other modally. If the vibrations matched, you’d get a reinforcing dynamic that would destroy the coupling and the generator. No pun intended, but developing the right dynamic coupling component is a balancing act.

To help quickly get to production, Robinson Rubber proposed a parallel development strategy, involving 20 different prototype designs varying in size, thickness and rubber formulation. The customer’s Engineering team tested the performance of all 20 units, narrowing the field down to the 3 most promising designs.

Robinson Rubber was able to modify these designs creatively and quickly for the final “fine tuning” to deliver the optimal component. In just 3 weeks’ time, it worked. And three months after starting their work together, Robinson Rubber had completed the mold design and testing and was in production with the final design. Finished parts were $5.87 each, not the $15-$20 estimated by the other firms. Robinson Rubber has now been supplying tens of thousands of these coupling devices per year without one field failure. And, rather than having to perform secondary operations to add heat- and ozone-protection to the device, Robinson Rubber developed a rubber formulation that in essence self-coats after molding. “This part came off our line ready for installation without the need to dip it, coat it or treat it with any other chemicals to give it robust ozone and heat-resistance”, says Jay Beck, President of Robinson Rubber.

In the end, Robinson Rubber showed engineering creativity to solve a problem quickly, with optimal engineering design, lower cost and high continuous quality.

Using up to 20 engineering grade polymers and more than 2,000 unique formulations, Robinson Rubber works with you to deliver the best rubber solution possible. Let us develop a proprietary custom formula for you using our in-house compound formulation and mixing capabilities.

Substrate materials include acetal, aluminum, brass, bronze, carbon steel, copper, ductile iron, fabric reinforcement, glass-filled composites, mineral-filled composites, nylon, PEEK, PES, phenolics, PTFE, PVDF and stainless steel. Molding an appropriate rubber gasket, support, seal, o-ring, mount, bushing, cover, wheel or other part directly to your part delivers an integral part that is less likely to leak, crack or otherwise fail in the field. Bondable substrates include single or multiple component substrates that are die cast, injection molded, stamped, waterjet cut, CNC machined or wire formed. “We can also bond rubber-tometal-to-plastic-to-fabric combinations. Providing sophisticated bonded assemblies of high quality is our specialty, with over 70% of our rubber being bonded to substrates,” says Beck. “This process delivers high performing components to our customers with virtually zero returns.”

Substrate parts include but are not limited to chain pads, conveyor pads, diaphragm assemblies, electrical insulators, ground spool valves, impellers, inflatable butterfly valve seats, motor mounts, non-invasive medical devices, power drive assemblies, sanding disks, special wheels, valve assemblies, vibration isolators and vibration mounts.

If you are an engineer struggling with trying to come up with components that will perform multiple functions in challenging conditions, check out rubber’s capability to bond to a variety of substrates, eliminate parts and lower assembly costs. A Polymer and Material Selection Guide is also available.

To learn more, email sales@robinsonrubber.com, visit www.robinsonrubber.com, or call toll free 1-877-619-5825 or 763-535-6737 for more information.