Hydraulic camshaft adjuster

#This application is a 371 National Phase of PCT/DE2018/100794, filed Sep. 19, 2018, which claims the benefit of German Patent Application No. 10 2017 126 171.0, filed Nov. 9, 2017.

#The disclosure relates to a hydraulic camshaft adjuster, comprising a stator, in which a rotor is arranged rotatably, the stator having at least one blade, the blade being arranged in a hydraulic chamber of the stator, with the result that a first part chamber is separated from a second part chamber, a central valve which controls the flow of hydraulic fluid into the first part chamber and into the second part chamber, a locking system, by way of which the rotor can be locked relative to the stator in a center position, the locking system comprising a first control element and a second control element which can be held in an unlocked position by way of loading with hydraulic fluid via the central valve, and which can bring about a locking action in the case of the removal of the pressure of the hydraulic fluid, it being possible for the first control element and the second control element to be brought into an operative connection with a slotted guide which is configured in the stator or a component which is connected to the latter, the slotted guide determining an axial position of the control element, a hydraulic pump for providing hydraulic fluid, and a tank for receiving hydraulic fluid.

#A hydraulic camshaft adjuster of this type is known, for example, from US 2016/069227 A1. In the case of a camshaft adjuster of this type, the aim is to bring about a locking function in the center position of the blade of the rotor in the hydraulic chamber.

#Exemplary embodiments of the disclosure are shown in the figures, in which:

#FIG. 1 diagrammatically shows the hydraulic control of a camshaft adjuster, the adjustment in normal operation being shown, in the case of which an adjustment has been carried out in the “advancing” direction,

#FIG. 2 diagrammatically shows the hydraulic control of the camshaft adjuster, the adjustment in normal operation being shown, in the case of which an adjustment has been carried out in the “retarding” direction,

#The figures diagrammatically show a camshaft adjuster 1 which has a stator 2 and a rotor 3 which can be rotated relative to the latter. The rotor 3 has a number of blades 4 which reach into respective hydraulic chambers 5 of the stator 2 and divide a first part chamber A from a second part chamber B here. During regular operation of the camshaft adjuster 1, a desired relative rotational position between the stator 2 and the rotor 3 is established by way of the feeding of hydraulic oil via a central valve 6 into the part chambers A and/or B.

#In the following text, only the novel features of the hydraulic camshaft adjuster are described, since the general method of operation of an adjuster of this type is well known. In respect of the hydraulic control of an element of this type and, in particular, in respect of the actuation of the adjuster with a central valve, reference is made expressly, for example, to DE 10 2013 226 437 B4 of the patent applicant, where detailed information in this regard is contained.

#Accordingly, during normal operation of the camshaft adjuster 1, the part chambers A and B are supplied with hydraulic oil in a desired way. In this operating mode, a locking system 7, 8 is passive, which is brought about by the fact that pressurized oil is conducted into a C-port. This has the consequence that two control elements 7 and 8 are pressed counter to a spring 10 by the pressure of the hydraulic fluid in such a way that the control elements 7 and 8 assume an unlocked position and therefore the camshaft adjuster 1 is in its normal operating position.