Insulation Tubing

PTFE liners as efficient inner lining for Bowden cables

GREMCO’s PTFE liners ensure high efficiency for the inner liners of mechanical actuating cables, which are also commonly referred to as Bowden cables.

How is a Bowden cable constructed?

The Bowden cable is a movable machine element for transmitting a mechanical movement, as well as compression and traction forces, by using a flexible combination of a wire rope and a sheath that is compression-resistant in the direction of extension. The Bowden cable consists of a steel wire or wire rope (traction cable), which is laid in a flexible sheath (traction sheath) that is compression-resistant in the direction of traction. This enables to guide the cable and additionally serves as a counter-bearing to the support of the transmitted tensile forces so that these can be transmitted from the Bowden cable along any curved path. If the Bowden cable runs along a curved path, the support provided by the inner cable generates compressive forces in the sheath, which is compressed as a result. A flexible sliding tube made of PTFE can be inserted between the sheath and the traction rope. Our PTFE liner can be used as such an inner liner. At this point, we would like to point out its excellent sliding properties and the resulting high efficiency. Soft PVC is usually used for the outer sheathing, which must follow the bends of the jacket without tearing. It protects the train and introduced lubricants from dust and moisture, thus preventing corrosion, increased friction, and freezing.

Why is GREMCO’s PTFE liner particularly suitable as an inner liner?

The difficult cable routing and rising temperatures found in a variety of applications, such as engine compartments, require the use of PTFE-based liners. Our Fitco® liners not only remain stable at high temperatures but can also be manufactured to exacting specifications in special geometries and very tight tolerances. In addition, we provide PTFE liners with individual filler packages, which thus increases mechanical strength, which is advantageous for many applications. Furthermore, the low coefficient of friction and high flexibility of natural PTFE ensures high performance in a variety of demanding applications. Lastly, PTFE’s resistance to heat, water, oil, and chemicals ensures a very long service life and a high number of actuation cycles while maintaining efficiency.

Typical application examples of Bowden cables with a PTFE liner from GREMCO as an inner liner in the automotive industry:

• door actuation
• hand brake cables
• flap actuators for engine hoods or trunks
• fuel filler flap
• seat actuation
• gearshift actuation or transmission actuation

Examples of applications of Bowden cables with a PTFE liner from GREMCO as inner lining in other areas:

• brakes and gearshifts in bicycles
• steering and throttle/clutch actuation in boats
• other industrial applications