Device for the axial support of a rotatable body, and positioning device provided with such a device

A device (1) for supporting a rotatable body (3) in a direction parallel to an axis of rotation (5) of the body (3). The device (1) comprises a support member (17) with a fluid bearing (21) which maintains a beating gap (23) between a bearing surface (15) of the body (3) extending perpendicular to the axis of rotation (5) and a bearing surface (19) of the support member (17) extending perpendicular to the axis of rotation (5) during operation. Manufacturing tolerances may lead to deviations from perpendicularity of the beating surfaces (15, 19) relative to the axis of rotation (5), which deviations cause an undesirable vibration of the body (3) parallel to the axis of rotation (5) during rotation of the body (3). This vibration is prevented in that the support member (17) is coupled to a frame (11) of the device (1) by means of an elastically deformable coupling member (25), whereby the bearing surface (19) is pivotable about two mutually perpendicular pivot axes (27, 29) which intersect in a point of intersection (31) of the axis of rotation (5) and the bearing surface (19). The point of intersection (31) of the axis of rotation (5), the pivot axes (27, 29) and the bearing surface (19) is defined in relation to the axis of rotation by means of the coupling member (25). The device (1) is used in a positioning device (127) for machining a rotatable workpiece (171) by means of a tool (149), during which the workpiece (171) is supported parallel to the axis of rotation (5) by the device (1).