Self-lubricating bearings keep ski bindings from binding

Located in the scenic village of Reichenbach, Switzerland, Fritschi is the world’s premier manufacturer of touring ski bindings. Its next-generation Diamir free-ride Alpine touring bindings, featuring a DIN setting of 12 and built-in brakes, allow skiers to go off the beaten path by enabling them to literally walk uphill in their skis.

The bindings are hinged at the toe, so when they are released at the heel, conventional downhill skis can be used as touring skis. To facilitate this movement, each binding incorporates two 5 mm inside-diameter, 10 mm long, self-lubricating bearings that are press-fitted into the hinge assembly at the front end of the polyamide-molded part. For normal descent, the heel of the binding is clamped to the ski, preventing it from moving.

Manufactured by GGB, formerly Glacier Garlock Bearings, Heilbronn, Germany, the bearings are exposed to harsh environmental conditions – temperatures that can range from -30°C to +30°C and ingress of moisture. Add to this loading on the bindings that in curves can reach two to three times the body weight of a skier. The high forces and shocks of downhill runs subject both the skis and bindings to bending moments that can induce some movement in the hinges. During walking, there might be a 60-degree movement every half-second under relatively light loading because the skier’s weight is shifted from one foot to the other. Typically, the service life of the bindings is several hundred hours.

The principal properties Fritschi sought in these bearings were low friction and maintenance-free performance. With a coefficient of friction 0.02-0.25, GGB DU® bearings provide excellent friction performance in rotating, sliding and oscillating motion applications. They can withstand static loads of up to 250 MPa, dynamic loads of up to 140 MPa, speeds up to 2.5 m/s and temperatures ranging from -200°C to +280°C.

The bearings consist of a rigid steel backing, which provides high load-carrying capacity, while a porous bronze inner layer impregnated with a homogeneous mixture of PTFE and lead provides superior lubricity and longevity.

To date the company, which produces hundreds of bindings a day and uses up to 300,000 bearings a year, reports no problems with the bindings or the bearings.

DU® self-lubricating bearings are press-fitted into the hinge assembly of the polyamide-molded part. Green plug keeps out dirt and moisture.

DU® self-lubricating bearings provide excellent friction performance in rotating, sliding or oscillating motion applications.