Method and device for operating a power steering system

Abstract

The invention relates to a method and a device for operating a power steering (10) of a motor vehicle, wherein a motor torque applied by an electric motor (16) is superimposed in a superposition unit (14) for a predetermined manual torque (24) (26), wherein by suitable measures, for example by evaluating the rotational speed pattern of the electric motor (16), it is recognized that the power steering mechanism (10) is starting to freeze, and wherein, in order to avoid that the power steering mechanism (10) freezing, the electric motor (16) is steered using an oscillating control signal, thereby utilizing the vibration torque (26) exerted by the electric motor (16) * ) contribute to an oscillatory loading of the power steering mechanism (10). According to the invention, instead of an oscillating control signal (S#) having a uniform amplitude (a0) acting in successive time periods (T0), the control signal (S#) is generated at this time * ), the control signal has a first period (T1) and has a second period (T2), the control signal (S * ) has an increased amplitude (a1) during the first period, the control signal (S * ) has no amplitude or a reduced amplitude (a2) during said second period, so that during said first period (T1), without thermal overload of said electric motor (16), exerted by the electric motor (16) with an increased maximum torque (M * ) vibration moment (26 * ) can be generated.

Description

technical field [0001] The invention relates to a method for operating a power steering system and a device for carrying out the method. Background technique [0002] In power steering systems of motor vehicles, a motor torque is usually superimposed by means of an electric motor on a manual torque applied by the driver. This superimposition is usually carried out by means of a superposition unit in the form of a superposition gear. Since power steering is generally used outdoors, it is exposed to external influences, in particular environmental influences and temperature influences. As a result, the functional effectiveness of the steering mechanism can be impaired. In particular, a possible freezing of the power steering due to ingress of water presents a particular problem here. [0003] Methods are known by which freezing of the power steering system is detected and countermeasures are taken. DE 10 2010 002 803 A1 discloses a method for operating a power steering sys...

AI Technical Summary

Problems solved by technology

As a result, the driver's injuries can be reduced; however, the relatively high frequency has the effect that the actually relatively high and therefore inert mass of the power steering system cannot vibrate freely enough

Furthermore, the oscillating motor current must not have too high an amplitude, since otherwise overheating of the electric motor and / or overheating of the control or controller would be encountered

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