Patent ID: 9631525
Date: 2017-04-25
CPC Classifications: F01L

Claim:
1. A cam phaser, comprising: an electromagnetically actuated hydraulic valve; and a hollow piston inserted in a borehole and longitudinally movable by an electromagnet so that a hydraulic fluid is distributed to a first operating connection and a second operating connection associated with a first pressure cavity and a second pressure cavity of the cam phaser, wherein the first operating connection branches off directly adjacent to the electromagnet from the borehole, wherein the hollow piston includes a circumferential bar with a control edge oriented towards the electromagnet so that a cavity within the borehole is defined on one side by the circumferential bar and on another side by the electromagnet, wherein a drain opening extends from the cavity, wherein the drain opening hydraulically connects the cavity with a drain channel leading towards a tank drain, wherein the circumferential bar is movable into a direction expanding the first operating connection in a flow cross section by a force of the electromagnet that is loaded with electrical current, wherein a spring force is oriented opposite to the force of the electromagnet and presses the bar in a direction reducing the flow cross-section, wherein a throttling location is provided at the circumferential bar which throttling location is arranged between the flow cross-section and the cavity, wherein the throttling location restricts a flow from the flow cross section into the cavity when the flow cross section is opened by the control edge, wherein the throttling location is configured as an annular gap that adjoins the bar, and wherein an axial length of the annular gap is greater than a radial thickness of the annular gap.