METHOD FOR ANCHORING A JOINING ELEMENT IN AN OBJECT AND JOINING ELEMENT TO BE USED IN THE METHOD

摘要

A joining element to be anchored in an object (10) with the aid of a ther moplastic material and mechanical vibration comprises a sealing portion (3.1 ) and a wall anchoring portion (3.2). The sealing portion (3.1) is substanti ally cylindrical and has a smooth circumferential surface. The wall anchorin g portion (3.2) has a circumferential surface which comprises the thermoplas tic material and energy directors. A cross section of the sealing portion (3 .1) envelops the cross section (including energy directors) of the wall anch oring portion and is arranged adjoining to the latter on its proximal side. The joining element is anchored in an opening (5) provided in the object (10 ) wherein a cross section of the opening corresponds to the cross section of the sealing portion (3.1) of the joining element such that the latter can b e forced into a mouth (5.1) of the opening (5) resulting in a press fit. For anchoring the joining element in the opening (5), mechanical vibrations e.g . ultrasonic vibrations are coupled into the joining element and the latter is forced into the opening (5) until at least a distal part of the sealing p ortion (3.1) is positioned within the opening. Thereby, the thermoplastic ma terial of the circumferential surface of the wall anchoring portion (3.2) is liquefied and pressed into the opening wall, wherein the sealing portion (3 .1) prevents the liquefied material to penetrate through the mouth and there fore the mouth (5.1) remains clear cut, i.e. does not get blurred by the liq uefied material.