About the Friction of the Wiper Windscreen Contact

Abstract

In order to study the influence parameters for the wiper-windscreen friction, a test system was built, using an assembly of a car plane auto rear window glass, with the electrical motor, the wiper mechanism and also a wiper with a modified arm (by inserting a transducer to measure the friction force, based on tensometric strain gauges). Also on the wiper arm, on the opposite side of the arm/blade connection (located approximatelly at the middle of the blade length) a loading system was mounted. Different loading forces can be applied to the blade contact by gravity by simple changing the mass placed on this system. A large number of experiments were performed for different combinations of the values for the blade oscillating period and for the normal force in dry and wetted conditions for the blade-windscreen contact. The obtained results, reveal a direct correlation of the friction force with the load mass and with the relative speed in the contact (blade moving period). A higher friction occurs for the dry contact. This force has a higher increasing tendency for this contact than for the wetted contact when a stabilisation tendency of the friction force occurs.