CV Joint Boot Designs Made to Last for the Life of a Vehicle
DuPont recently celebrated the 25th anniversary of DuPont™ Hytrel® thermoplastic polyester elastomer in CV joint boot applications.
In that time, over 1 billion durable constant velocity (CV) joints for cars, trucks and other vehicles have been manufactured incorporating protective boots made with Hytrel®.
The Road Warrior
Constant-velocity joints allow a rotating shaft to transmit power from the transmission to the wheels. Boots protect that critical component from contaminants outside and keep lubricants inside. Any crack or tear in the boot can cause the essential constant velocity joint it protects to fail.
On average, a CV joint boot endures 150,000 miles of continuous flexing, pelting and thermal cycling. So the longevity experienced with boots made with Hytrel®, achieved over a 25-year period, is a significant achievement.
Contributing to Lighter Cars
The durability and high-temperature and chemical resistance of Hytrel® are properties which have helped engineers design smaller, more cost-effective boots, to help reduce vehicle weight, and support fuel efficiency.
Making Production More Efficient
By reducing the size of the CV joint boot, Hytrel® helps reduce materials costs. With a wide variety of grades, it can be processed in a range of blow-molding equipment and processes. DuPont application development resources work closely with part-makers and end-users to help them specify and manufacture the best solution for each boot and vehicle.
DuPont continues to develop a range of CV joint boot materials, including new grades of Hytrel® and also DuPontTM Vamac® ethylene acrylic elastomer, which offers high-heat resistance and excellent molding properties. Key performance features of Vamac® include:
- Low melt viscosity for molding complex shapes.
- Excellent oil and grease resistance.
- Heat resistance up to 170°C
- Little or no distortion during rotation.
Another Vamac® product, DuPont™ Vamac® Ultra, is often selected for hot-side inboard CV joint boots for its combination of cost-effectiveness and its resistance to both grease and punctures.