Filter device and method for its manufacture

The method for manufacturing a filtration mechanism with a pleated filter material body made of filter material layers and a framework, comprises connecting the framework with a section of a border region of the filter material body by ultrasonic welding process by the formation of an arrangement having the body, an energy director (3) and the framework, arranging the body, the energy director and the framework in a series manner adjacent to one another, focusing the welding energy, and leading the welding energy into the arrangement with the help of a sonotrode (5). The method for manufacturing a filtration mechanism with a pleated filter material body made of filter material layers and a framework, comprises connecting the framework with a section of a border region of the filter material body by ultrasonic welding process by the formation of an arrangement having the body, an energy director (3) and the framework, arranging the body, the energy director and the framework in a series manner adjacent to one another, focusing the welding energy, leading the welding energy into the arrangement with the help of a sonotrode (5), building the welding joint between the body and the framework elements as linear weld seams between the flanks of the folds and the interior of the lateral frame elements. The sonotrode is placed during the welding process in such a manner that the welding energy is focused by the sonotrode into the framework and filter material body and is passed through the framework, the energy director, the filter material body and a region, in which a welding joint is formed in a section. The energy director is designed as an integral single-component or non-integral component of the framework and/or the filter material body. The energy director is made of a material that has similar thermal characteristics of the same material as the body and/or the framework. Before the ultrasonic welding process, a section of body is inserted into a tool holder (4) in such a manner that the border region of the body to be welded protrudes from the tool holder and/or hangs freely from the same as a counter-pressure element for the framework that is exposed to the sonotrode during the welding process. The energy director is placed between the region of the filter material body and between the regions of the framework. A unit is used as energy director, whose profile corresponds to the flanks of the folds. The energy director is designed as a corresponding strip-