Hydrostatic power steering device

摘要

Hydrostatic power steering devices transmit the steering force to the steered wheels via oil columns enclosed in lines. Such steering systems consist essentially of a metering pump (5) and a steering valve (2) which are combined to form one constructional unit. Via a steering valve (2), the metering pump (5) distributes to a steering motor (8) in accordance with the rotational movement at a steering wheel the stream of oil produced by a servo pump (1). The stream of oil synchronises the rotational angle at the steering wheel with the locking angle of the steered wheels. Hydrostatic steering systems tend to experience pressure vibrations. According to the invention, these pressure vibrations are reduced whilst avoiding excessively high pressure losses. In a feed line (4) to the steering system, a damping valve (11) is provided whose damping piston (12) shuts off, in a central position which is centred by springs (13, 14), a branch line (6) which branches off to the metering pump (5). When pressure control occurs by means of a rotational movement at the steering wheel, the damping piston (12) opens a flow cross-section from the feed line (4) to the branch line (6) leading to the metering pump (5). By means of this measure, rapid pressure changes in the feed line (4) when there is a drawing off of flow at the metering pump (5) only affect the branch line (6) in a delayed fashion (Fig. 3). <IMAGE>