GB1502788A - Servo-steering control systems for vehicles - Google Patents

Abstract

1502788 Power-assisted steering mechanisms AUTOMOBILES CITROEN SA 14 May 1975 [16 May 1974] 20468/75 Addition to 1386155 Heading B7H A power-assisted steering mechanism of the kind described in Specification 1,386,155 and comprising a slide valve 2 which is moved axially through a kinematic connection including pinions 16, 17, 20, 21, levers 26, and a cross-bar 29 so as to distribute pressure fluid to a servocylinder (not shown) in response relative angular displacement between an input shaft 4 and an output shaft 14, is characterized by the provision of spring means which take up backlash occurring between elements of the kinematic connection. In the embodiment of Fig. 2, the spring means comprise a spring 40 exerting an axial force on the slide valve 2, and spring rods 47 acting between the pinions 16 and 20 so as to cause an axial force on the slide valve 2 in the opposite direction to the force exerted by the spring 40. Relative angular displacement of the shafts 4 and 14 is limited by the engagement of pin 13a carried by the shaft 14 with cut-out portions 13 of a sleeve 4a carried by the shaft 4. In a modification of the Fig. 2 embodiment, the spring rods 47 are replaced by a spring 52, Fig. 3, of generally C-shape. One end 54 of the spring 52 engages the pin 13a while the other end 53 of the spring 52 engages a recess 55 of the sleeve 4a.