Hydraulic camshaft adjuster

Abstract

A camshaft phaser for variably adjusting the control times of gas exchange valves of an internal combustion engine, including: a stator and a rotor which can be rotated relative to the stator, wherein a plurality of hydraulic chambers are formed between the stator and the that are separated by radially inwardly projecting webs of the stator. Radially outwardly projecting vanes are formed on the rotor that divide each of the hydraulic chambers into first and second groups of working chambers with an opposing effective direction. A pressure medium pump is adapted to apply a pressure medium to the working chambers. A central valve controls the oil pressure in the working chambers. The pressure medium pump is directly connected to the working chambers in each ease via a pressure medium channel; the central valve is connected to the working chambers via discharge channels; and the central valve exclusively controls the pressure medium discharge from the working chambers.

1 . A hydraulic camshaft phaser for variably adjusting control times of gas exchange valves of an internal combustion engine, the hydraulic camshaft phaser comprising:
 a stator and a rotor which is rotatable relative to the stator;   a plurality of hydraulic chambers formed between the stator and the rotor;   radially outwardly projecting vanes formed on the rotor, said vanes dividing each of the hydraulic chambers into a first group of working chambers and a second group of working chambers with an opposing effective direction;   a central valve configured to control oil pressure in the working chambers;   respective pressure medium channels configured to supply a pressure medium directly to the working chambers from a pressurized pressure medium source;   the central valve is connected to the working chambers via discharge channels; and   the central valve exclusively controls a pressure medium discharge from the working chambers.   
     
     
         2 . The hydraulic camshaft phaser according to  claim 1 , further comprising:
 a first check valve arranged in a first one of the pressure medium channels which connects a pressure medium pump acting as the pressurized pressure medium source to the first group of working chambers, and   a second check valve arranged in a second one of the pressure medium channels which connects the pressure medium pump to the second group of working chambers.   
     
     
         3 . The hydraulic camshaft phaser according to  claim 2 , further comprising:
 a check valve plate in which the check valves are arranged or formed.   
     
     
         4 . The hydraulic camshaft phaser according to  claim 2 , wherein
 one of the check valves is assigned to each of the first group of working chambers and to each of the second group of working chambers in the pressure medium channels.   
     
     
         5 . The hydraulic camshaft phaser according to  claim 1 , further comprising:
 a drive wheel with drive toothing, and   the pressure medium channels extend at least in sections in the drive wheel.   
     
     
         6 . The hydraulic camshaft phaser according to  claim 5 , wherein
 the drive wheel is a sintered component.   
     
     
         7 . The hydraulic camshaft phaser according to  claim 1 , wherein the rotor is a sintered component, and at least one of the pressure medium channels or the discharge channels are formed in an end face of the rotor. 
     
     
         8 . The hydraulic camshaft phaser according to  claim 1 , wherein
 the rotor comprises a first rotor component and a second rotor component.   
     
     
         9 . The hydraulic camshaft phaser according to  claim 8 , wherein
 the rotor components are stamped parts.   
     
     
         10 . The hydraulic camshaft phaser according to  claim 1 , further comprising:
 a pressure medium return path that leads from the working chambers via the central valve, and a check valve arranged in the pressure medium return path downstream of the central valve or downstream of a pump inlet of a pressure medium pump.   
     
     
         11 . A hydraulic camshaft phaser for variably adjusting control times of gas exchange valves of an internal combustion engine, the hydraulic camshaft phaser comprising:
 a stator;   a rotor located in and rotatable relative to the stator;   a plurality of hydraulic chambers formed between the stator and the rotor;   radially outwardly projecting vanes formed on the rotor, said vanes dividing each of the hydraulic chambers into a first group of working chambers and a second group of working chambers that have opposing effective directions;   a central valve configured to control a pressure medium pressure in the working chambers;   respective first and second pressure medium channels configured to supply pressure medium directly to the first group of working chambers and the second group of working chambers from a pressurized pressure medium source;   respective first and second discharge channels that connect the central valve connected to the first group of working chambers and the second group of working chambers;   an actuator configured to control the central valve; and   the central valve exclusively controls a pressure medium discharge via the first and second discharge channels from the working chambers.   
     
     
         12 . The hydraulic camshaft phaser according to  claim 11 , further comprising:
 a first check valve arranged in the first pressure medium channel which connect the pressurized pressure medium source to the first group of working chambers, and a second check valve arranged in the second pressure medium channel which connects the pressurized pressure medium source to the second group of working chambers.   
     
     
         13 . The hydraulic camshaft phaser according to  claim 12 , further comprising:
 a check valve plate in which the check valves are arranged or formed.   
     
     
         14 . The hydraulic camshaft phaser according to  claim 12 , wherein one of the check valves is assigned to each of the first group of working chambers and to each of the second group of working chambers in the pressure medium channels. 
     
     
         15 . The hydraulic camshaft phaser according to  claim 11 , further comprising:
 a drive wheel with drive toothing, and   the pressure medium channels extend at least in sections in the drive wheel.   
     
     
         16 . The hydraulic camshaft phaser according to  claim 11 , wherein the drive wheel is a sintered component. 
     
     
         17 . The hydraulic camshaft phaser according to  claim 11 , wherein the rotor is a sintered component, and at least one of the pressure medium channels or the discharge channels are formed in an end face of the rotor. 
     
     
         18 . The hydraulic camshaft phaser according to  claim 11 , wherein the rotor comprises a first rotor component and a second rotor component. 
     
     
         19 . The hydraulic camshaft phaser according to  claim 18 , wherein the first and second rotor components are stamped parts. 
     
     
         20 . The hydraulic camshaft phaser according to  claim 11 , further comprising:
 a pressure medium return path that leads from the working chambers via the central valve; and   a check valve arranged in the pressure medium return path downstream of the central valve or downstream of a pump inlet of the pressure medium source.