Torsional element for steering valves and spring characteristic improving process

摘要

PCT No. PCT/EP96/02614 Sec. 371 Date Apr. 25, 1997 Sec. 102(e) Date Apr. 25, 1997 PCT Filed Jun. 18, 1996 PCT Pub. No. WO97/00189 PCT Pub. Date Jan. 3, 1997A torsion element (1) for a steering valve is provided. The torsion element (1) comprises a torsionally elastic rod member (2) having axially opposite first and second end areas (3, 4) which are rotatable relative to one another. The rod member (2) has a circumferentially spaced plurality of radially and axially extending indentations (10) adjacent the second end area. A generally tubular, torsionally stiff sleeve member (6) encircles the rod member (2) and is fixedly attached to the first end area (4) of the rod member. The sleeve member (6) includes a circumferentially spaced plurality of radially and axially extending grooves (9) which align with and radially overlie the plurality of indentations (10) in a neutral steering condition. The sleeve member (6) further includes a circumferentially spaced plurality of radial slots (7). The plurality of grooves (9) cooperates with the plurality of indentations (10) to exert a radially directed centering force on the rod member (2) upon rotation of one of the end areas (3, 4) of the rod member from the neutral steering condition.