DE102014215136B4 - Optimized hydraulic center lock for camshaft adjuster - Google Patents

Abstract

Hydraulic camshaft adjuster (1), constructed as a vane-type adjuster with which a phase angle of a camshaft relative to a crankshaft can be held or changed, wherein the camshaft adjuster (1) comprises a stator (2) and a rotor (3) and a guide system (24 ), the pressure or hydraulic fluid with the interposition of a hydraulic valve (14) and with connecting lines (32, 33) and hydraulic lines (30, 31, 38, 39) at least one pressure chamber (6a, 6b, 6c) feeds or discharges, wherein the pressure chambers (6a, 6b, 6c) are in each case divided by a rotor-fixed wing (5a, 5b, 5c) into separate working chambers (7, 8; 9, 10, 11, 12) which form mutually opposing chamber pairings, wherein in at least one wing (FIG. 5b, 5c) a control device (21, 22) is inserted, which is for selectively releasing and interrupting a flow connection (42, 43) between the respective opposite working chambers (9, 10, 11, 12) is determined, and via a control element (23) switchable hydraulic valve (14) comprises a plurality of work spars (18, 19, 20) and connected to a pressure source P-port (16) and a T-port associated with a tank (17) and in the rotor (3) a locking device (13) is integrated, consisting of two axially adjustable, spring-loaded locking piston (25, 26) which prevent a relative movement between the rotor (3) and the stator (2), if necessary, in which at least one locking piston ( 25, 26) is displaceable from a first switch position against a spring force into a second switch position and locked in a locking slot (29) during a rotation of the rotor (3) from the direction of a stop position EARLY or LATE in a center locking position (MVP), characterized that each locking piston (25, 26) of the locking device (13) has an axial bore (36, 37), which in a position coincidence with a verb indent line (32, 33) each produces a separate flow connection between the working chambers (7, 8) of a pressure chamber (6a).

Description

The invention relates to a hydraulic camshaft adjuster according to the features of the preamble of claim 1.

Such camshaft adjusters are used to change the timing of gas exchange valves of an internal combustion engine during operation as needed, in order to improve the fuel consumption and the performance of the internal combustion engine.

A proven in practice embodiment is constructed as Flügelzellenversteller camshaft adjuster with a stator and a rotor, which define an annular space, which is divided by wings in two working chambers. The working chambers are optionally acted upon by a hydraulic medium, which is fed in a pressure medium circuit via a pressure medium pump from a pressure medium reservoir in the working chambers on a wing side of the rotor and is returned from the working chambers of the other wing side in the pressure medium reservoir. The working chambers whose volume is thereby increased, have a direction of action, which is opposite to the effective direction of the associated opposite working chamber. By the direction of action, a rotation of the rotor can be triggered either clockwise or counterclockwise relative to the stator. The control of the pressure fluid flow and thus the adjustment of the camshaft adjuster includes a hydraulic multi-way actuator, are closed or released in response to a position of a valve body flow openings.

One problem with these camshaft adjusters is that they are not completely filled with pressure medium or run empty in a startup phase. At a start, when the oil pressure within the internal combustion engine is not yet established, the alternating torques exerted by the camshaft can cause uncontrolled movements of the rotor relative to the stator, which can lead to increased wear and undesired noise development. To avoid this problem, it is known to provide a locking device between the rotor and the stator, which locks the rotor when stopping the internal combustion engine in a favorable for the start angle of rotation position relative to the stator.

Locking devices of this type preferably comprise spring-loaded locking pins which, when the rotor rotates, lock successively in locking slots provided on the sealing cover or the stator. In this case, a rotation of the rotor in the direction of the central locking is possible before reaching a center locking position, but blocks a rotation of the rotor in the opposite direction. After warming up of the internal combustion engine and / or the complete filling of the camshaft adjuster with pressure medium, the locking pins are displaced pressure medium actuated from the locking slots, so that the rotor is then intended to rotate relative to the stator for adjusting the rotational angle position of the camshaft.

From the document US Pat. No. 6,684,835 B2 is a hydraulic, known as Flügelzellenversteller built camshaft adjuster whose center locking occurs when stopping the engine. An electronic control unit detects a signal that is generated when stopping the engine, and signals that reflect the state of the stator relative to the rotor. An electrical control valve comprises five ports, one port of which receives the oil flow from the engine or hydraulic fluid circuit, one port connects the solenoid to all of the lock pistons or interlock pins, and two ports connecting the solenoid to the working chambers of the camshaft pressure chambers port connected to a tank for a return of the oil or hydraulic fluid from the control valve.

The post-published DE 10 2013 207 617 A1 shows a Nockenwellenverstelleinrichtung with a Fluegelzellenversteller with a connectable to a crankshaft of an internal combustion engine stator and a rotatably mounted in the stator, connectable to a camshaft rotor, and a center locking device for locking the rotor in a center locking position relative to the stator, the center locking device at least two in one stator-locked locking link lockable, spring-loaded locking pins which lock at a rotation of the rotor from a stop position "early" or "late" in the center locking position from different directions in the locking link, wherein at least a first locking pin. a blocking section and a freely flow-through pressure medium line are provided, via which in the various positions of the first locking pin a flow connection between two working chambers of different effective direction can be produced or blocked, and the working chambers of the different effective directions are kurzschließbar means of a switching device, and in at least one pressure medium line, which through the freely flowable pressure medium line of the locking pin fluidically to the Pressure medium circuit is connected, a check valve is provided, which an inflow of the pressure medium in one of the working chambers whose volume increases in a rotation of the rotor from the direction of one of the stop positions "early" or "late" in the direction of the center locking position allows, and a back flow same working chamber prevented simultaneously.

The object of the present invention is to provide a center locking concept which reliably and quickly locks regardless of the angular position before stop or regardless of the angular position at startup of the internal combustion engine.

This object of the invention is achieved by a camshaft adjuster with the features of claim 1. Further preferred embodiments of the invention can be found in the subclaims, the figures and the associated description.

According to the basic idea of the invention, a locking device is provided for achieving the object, in which each separately or jointly adjustable locking piston of the locking device has an axial bore which produces a separate flow connection between the working chambers of a pressure chamber in a position match with connecting lines. The inventive solution causes a shortening of the oil or pressure fluid path between the working chambers of a pressure chamber by a targeted separation of the adjustment mechanisms. According to the invention, the process of center locking is limited to the chamber pairing of a pressure chamber of the camshaft adjuster. The chamber pairs of the other pressure chambers are determined for the adjustment of the camshaft in normal operation of the internal combustion engine, which are consistently shorted during the locking phase. Advantageously, by the measure according to the invention a shortened compared to previous solutions oil path between two oil chambers, connected to an advantageously low hydraulic flow resistance. Consequently, the influence of the oil viscosity on the locking speed is of little importance, so that the center locking position (MVP) is reached before the internal combustion engine comes to a standstill. If the camshaft adjuster has not been locked, for example by stalling the internal combustion engine, then the concept according to the invention allows the locking process to take place the next time the internal combustion engine is started up.

By the inventive concept results in comparison to previous known solutions during the locking process at a stop or start of the internal combustion engine advantageously a significantly reduced pressure medium or hydraulic fluid connection. The structure according to the invention has an advantageous effect at low oil or pressure medium temperatures, in particular below zero degrees, in which an increased oil viscosity occurs, associated with a slowed flow velocity. With increasing length of the oil line and at a given oil pressure, the throttling of the volume flow continues to increase. For the locking process when the internal combustion engine stops so that the adjustment of the camshaft adjuster extends in the direction of the center. Due to the boundary conditions according to the invention with the significantly shortened pressure fluid or hydraulic fluid connection, the center locking position (MVP) can be realized in a stop of the internal combustion engine in the available time of about 0.3 seconds. Previous concepts required due to a long hydraulic fluid connection and high oil viscosity for the locking process several seconds, whereby the camshaft adjuster remained at standstill of the internal combustion engine in the unlocked state and consequently in an undefined angular position. In the same way, the locking process of the camshaft adjuster is also influenced by the length of the hydraulic fluid connection during a start of the internal combustion engine. The invention achieves a fast center lock desired by vehicle and engine manufacturers prior to the first ignition.

The separation of the adjustment mechanisms according to the invention, combined with the shortened pressure medium lines, leads to a task-oriented and reliable center locking, which ensures an optimal start of the internal combustion engine. On the other hand, the inventive concept, regardless of the angular position at standstill of the internal combustion engine in the starting phase of the internal combustion engine, a secure center locking position, for example, when the stoppage of the internal combustion engine was carried out by stalling. Advantageously, the inventive measure requires neither an adaptation of the control unit of the internal combustion engine nor an additional space outside of the camshaft adjuster, which also quickly adjusted and locked even in high oil viscosity due to low oil temperatures in the direction of the center locking position.

Another measure of the invention provides that the center locking is initiated at a stop or a start of the internal combustion engine by switching the hydraulic valve in a position in which the locking gates are connected via the hydraulic valve to the tank, whereby the hydraulic fluid flows out without pressure. A connecting line, the axial bore with the Combines working chambers, it is interrupted by the latching in the locking engagement locking piston. The second unlocked positioned locking piston allows for a position coincidence with the other connecting line replacement of the hydraulic fluid between the working chambers.

According to an advantageous embodiment of the invention, it is provided that the connecting line and thus intended for the center locking working chambers via the axial bore and a tap hole of the locking piston, the locking link and hydraulic lines with the C-port of the hydraulic valve in contact. In addition, the arrangement according to the invention makes it possible for oil or hydraulic fluid to flow into the working chambers during normal operation of the internal combustion engine, as compensation for external oil leakage.

Further, the invention provides that by a corresponding circuit of the hydraulic valve in normal operation of the internal combustion engine, both locking piston of the locking device acted upon by the pressure of the hydraulic fluid displaced into the rotor and thus unlocked. In this position corresponding to a short-circuit of the locking piston, an oil or hydraulic fluid exchange and consequently a pressure compensation between the working chambers of a pressure chamber can be adjusted via the axial bores and the associated connecting lines in both directions of flow. The hydraulic freewheel is thus deactivated. Furthermore, in all working chambers of the further pressure chambers of the camshaft adjuster, the control pistons of the control device integrated in the vanes are displaced by the oil pressure, so that a connection between the opposing working chambers is interrupted. This builds up in these chamber pairings an equal pressure difference on the wing, which in turn causes an adjustment of the camshaft adjuster in the desired adjustment direction. A further measure provides for each locking piston of the locking device to assign a spring element, which acts on the locking piston in the direction of the locking link. A displacement of the locking piston takes place as soon as a counteracted by the hydraulic fluid counterforce fails.

For the function of the locking device, it is advantageous if the locking piston intended for a locking in the direction of EARLY interrupts a hydraulic fluid flow of the first connecting line to the working chambers in a locked position extended from the rotor. In contrast, the locking piston intended for locking in the direction LATER prevents a hydraulic fluid flow of the second connection line to the working chambers in a locked position extended from the rotor.

According to a preferred arrangement, the camshaft adjuster according to the invention comprises more than two, preferably four, symmetrically placed in the stator pressure chambers, each of which forms separate chamber pairs by a wing.

A further arrangement according to the invention provides for influencing a pressure ratio of the camshaft adjuster, for example to provide the stator with an additional component in order to purposefully reduce the working chambers of a pressure chamber. For hydraulic camshaft adjusters so far a mechanically determined pressure ratio between 2.5 to 5 Nm / bar is provided. By means of the additional component according to the invention, a camshaft adjuster can advantageously be realized with a reduced pressure ratio. A smaller pressure ratio has the consequence that during the locking process less oil or hydraulic fluid between the oil or working chambers of a pressure chamber has to be pumped. This results in the sum of a higher adjustment speed, which in turn leads to a preferred shorter locking process. The reduced pressure ratio can be realized, for example, by an additional component, which is attached directly to the stator or to a cover of the stator.

The invention will be explained in more detail with reference to a preferred embodiment with reference to several drawings. However, the invention is not limited to this embodiment. The figures show:

1 a schematic functional representation of a hydraulic camshaft adjuster according to the invention during a displacement movement of the rotor from the direction of LATE into the center locking position;

2 : a schematic functional representation according to 1 during an adjustment movement of the rotor from the direction of EAR to the center locking position;

3 : a schematic functional representation according to 1 during an adjustment movement of the rotor from the direction of EAR towards LATE during the engine operation or normal operation of the internal combustion engine;

4 : a schematic functional representation according to 1 during an adjustment movement of the rotor from the direction of LATE in the direction of EAR during the engine operation or normal operation of the internal combustion engine;

5 : a schematic functional representation according to 1 in which the camshaft adjuster is held in a desired position by means of appropriate switching of the hydraulic valve; and

6 : a schematic functional representation according to 1 in which a pressure chamber is assigned an additional component for influencing a pressure ratio of the camshaft adjuster.

In all figures, the camshaft adjuster according to the invention is shown schematically, wherein the figures do not include all components of the camshaft adjuster. Identical elements or components are provided with matching reference numerals.

The 1 shows a camshaft adjuster 1 with a known basic structure as a wing cell type, which preferably uses oil of the internal combustion engine as the hydraulic medium. The camshaft adjuster 1 includes a driven by a crankshaft of an internal combustion engine, not shown, stator 2 and a rotor rotatably connected to a camshaft (not shown) 3 , A rotor hub 4 of the rotor are a plurality of radially aligned wings 5a . 5b . 5c assigned to the pressure chambers 6a . 6b . 6c in the stator 2 in working chambers 7 to 12 subdivide and doing chamber pairings 7 . 8th ; 9 . 10 and 11 . 12 form. The upper illustration of 1 shows the camshaft adjuster 1 in a settlement, while lower left schematically a section of the rotor hub 3 of the rotor 2 including a locking device 13 is shown and lower right schematically a constructed as a multi-way valve hydraulic valve 14 for controlling the pressure or hydraulic fluid for the camshaft adjuster 1 , The hydraulic valve 14 includes five ports and is in four control positions 15a to 15d adjustable. A P port 16 or Zulaufport communicates with a pressure pump or a pressure fluid circuit of the internal combustion engine and a T-port 17 is assigned to a tank or pressure medium reservoir. The A-port 18 makes a connection for one to the working chambers 9 and 11 leading hydraulic line 38 , The at the B-port 19 connected hydraulic line 39 stands with the working chambers 10 and 12 in connection. At the C-port 20 is the hydraulic line 30 connected with those in the wings 5b . 5c integrated control devices 21 . 22 connected is. Another with the hydraulic line 30 connected hydraulic line 31 is at the locking device 13 connected. All ports are according to the control position of the hydraulic valve 14 either open or closed. The pressurized by a spring element hydraulic valve 14 is via a preferably designed as an electromagnet actuator 23 adjustable as needed in the respective control position.

The 1 also shows a from the hydraulic lines 30 . 31 . 38 . 39 formed control system 24 via which the hydraulic valve 14 with the locking device 13 and the pressure chambers 6a to 6c connected is. The locking device 13 comprises two locking pistons, also referred to as locking pins 25 . 26 which linearly displaceable in a receptacle 27 . 28 the rotor hub 4 are used, each locking piston 25 . 26 in the direction of a locking link 29 from a spring element 44a . 44b is arranged spring loaded. Each locking piston 25 . 26 is via separate connection lines 32 respectively. 33 with the chamber pairing forming working chambers 7 and 8th of the pressure chamber 6a connected. The connection line 32 begins in the work chamber 7 , wherein the oil or hydraulic fluid via an axial bore 36 of the locking piston 25 and through a first check valve 34 in the wing 5a into the oil or working chamber 8th can flow as soon as a positional match between the axial bore 36 and the connection line 32 established. The second connection line 33 begins in the work chamber 8th , leads over the axial bore 37 of the locking piston 26 to the second check valve 35 in the wing 5a and then into the working chamber 7 ,

At a stop of the internal combustion engine, the locking operation by switching the hydraulic valve 14 in the tax position 15a initiated. The C-port 20 of the hydraulic valve 14 is on the one hand via hydraulic lines 30 and 31 with a locking link 29 and then on the T-port 17 connected to the tank, which causes the oil pressure in the locking latches 29 lowers to an ambient pressure. With a displacement of a locking piston 25 or 26 in the locking frame 29 becomes one with both working chambers 7 . 8th in contact connection line 32 or 33 interrupted. At the same time all other chamber pairings 9 and 10 such as 11 and 12 through those in the wings 5b . 5c existing, control piston 40 . 41 enclosing control devices 21 . 22 shorted and thus overridden. The oil or hydraulic fluid can now during the adjustment directly without adversely affecting the locking process between the working chambers 9 . 10 respectively. 11 . 12 stream. Only a short flow connection 42 . 43 in the wings 5b . 5c causes a low hydraulic flow resistance. When locking in the direction of the arrow, starting from a position LAT according to 1 towards EARLY, the locking piston locks 25 after switching the hydraulic valve 14 in the position 15a due to the oil pressure drop in the locking link 29 , This will affect the working chamber 7 connected connection line 32 interrupted. Through the check valve 35 can now get oil from the chamber 8th in the chamber 7 stream. If an existing cam change torque after switching off the ignition, the camshaft adjuster 1 in the direction of EARLY, the wing pushes 5a the oil from the working chamber 8th the shortest way over the connecting line 33 , the axial bore 37 in the locking piston 26 in the working chamber 7 , If the camshaft alternating torque acts in the opposite direction, the check valve closes 35 , resulting in between both working chambers 7 . 8th no oil or hydraulic fluid exchange. The rotor 3 is thus prevented from swinging in the opposite direction of adjustment. Due to the short flow path between the working chambers 7 . 8th the hydraulic flow resistance is low. Consequently, the influence of the oil viscosity on the adjustment is only of minor importance. Due to the changing cam torque, the system acts like a hydraulic freewheel. The inventive concept ensures the reliable achievement of the center locking position with subsequent locking before the internal combustion engine comes to a standstill. At a start of the internal combustion engine results in a similar situation. If the camshaft adjuster has not been locked, for example by stalling the internal combustion engine, the locking process can take place when the internal combustion engine starts.

The 2 illustrates the locking process from the position EARLY. Instead of the locking piston 25 locked in this case the locking piston 26 in the locking frame 29 , This will be the connection line 33 which are in the oil or working chamber 8th begins, interrupted. If the camshaft adjusting torque acts in the LATE direction, the sash pushes 5a the oil or hydraulic fluid of the working chamber 7 through the connection line 33 over the axial bore 37 in the locking piston 26 as well as through the check valve 34 in the working chamber 8th , If the camshaft alternating torque tilts, the rotor remains 3 in the stator 2 stand as the check valve 34 closes automatically with a negative pressure difference. The oil exchange in all other oil chamber pairings of the camshaft adjuster 1 takes place according to 1 through the short in the wings 5b . 5c but in an opposite direction of flow.

The 3 and 4 refer to the adjustment process of the camshaft adjuster 1 during operation, normal operation of the internal combustion engine. It takes the hydraulic valve 14 the position 15b or 15d one, the C port 20 each via the P port 16 is pressurized. Through the hydraulic lines 30 . 31 is the C-port 20 with the locking link 29 connected, whereby both locking pistons 25 . 26 in the rotor 3 are indented. In this shorting corresponding position of the locking piston 25 . 26 can be an oil exchange between the working chambers 7 and 8th adjust in both directions, whereby simultaneously the hydraulic freewheel is deactivated. At the same time, the control pistons are displaced due to the pressurization 40 . 41 the control devices 21 . 22 in the wings 5b . 5c the further chamber pairings 9 . 10 such as 11 . 12 , so that a flow connection 42 . 43 between the respective opposite working chambers 9 . 10 and 11 . 12 is interrupted. Thus, in each chamber pairing, the same pressure difference on the wings 5b . 5c build, which in turn causes an adjustment in the desired adjustment. About the axial holes 36 . 37 in connection with tap holes 46 . 47 the locking piston 25 . 26 as well as the connecting lines 32 . 33 can during normal operation of the engine oil or hydraulic fluid in both working chambers 7 . 8th inflow to compensate for external oil leakage.

In the 5 is the camshaft adjuster 1 imaged in a desired or defined angular position. This can be achieved by a circuit of the hydraulic valve 14 in the position 15c be reached or held, in which a connection of the C-port 20 with the P port 16 adjusts to pressurize the locking device 13 and the controllers 21 . 22 , In the position 15c of the hydraulic valve 14 are the A-port 18 as well as the B-port 19 blocked.

According to 6 includes the hydraulic phaser 1 an additional component 45 that the stator 2 is assigned and about the pressure chamber 6a can be limited. The disc-shaped, directly on the stator 2 attached or a separate cover of the stator 2 assigned component 45 reduces the working chambers 7 . 8th , This can be a desired smaller pressure ratio of the camshaft adjuster 1 be realized, which reduces the volume of oil or hydraulic fluid, during the locking process between the working chambers 7 and 8th is pumped around. With this measure, the adjustment speed increases, which shortens the locking process.

LIST OF REFERENCE NUMBERS

1

Phaser

2

stator

3

rotor

4

rotor hub

5a, 5b, 5c

wing

6a, 6b, 6c

pressure chamber

7

working chamber

8th

working chamber

9

working chamber

10

working chamber

11

working chamber

12

working chamber

13

locking device

14

hydraulic valve

15a, 15b, 15c, 15d

control position

16

P port

17

T port

18

A port

19

B port

20

C-Port

21

control device

22

control device

23

actuator

24

Control System

25

locking piston

26

locking piston

27

admission

28

admission

29

locking link

30

hydraulic line

31

hydraulic line

32

connecting line

33

connecting line

34

check valve

35

check valve

36

drilling

37

drilling

38

hydraulic line

39

hydraulic line

40

spool

41

spool

42

flow connection

43

flow connection

44a, 44b

spring element

45

component

46

branch bore

47

branch bore

Claims (9)

Hydraulic camshaft adjuster ( 1 ), constructed as a vane-type phaser with which a phase angle of a camshaft relative to a crankshaft can be kept or changed, wherein the phaser ( 1 ) a stator ( 2 ) and a rotor ( 3 ) and a control system ( 24 ), the pressure or hydraulic fluid with the interposition of a hydraulic valve ( 14 ) and with connecting cables ( 32 . 33 ) and hydraulic lines ( 30 . 31 . 38 . 39 ) at least one pressure chamber ( 6a . 6b . 6c ) or discharges, the pressure chambers ( 6a . 6b . 6c ) each of a rotor-fixed wing ( 5a . 5b . 5c ) in separate, mutually acting, chamber pairings forming working chambers ( 7 . 8th ; 9 . 10 ; 11 . 12 ), wherein in at least one wing ( 5b . 5c ) a control device ( 21 . 22 ) for selectively enabling and interrupting a flow connection ( 42 . 43 ) between the respective opposite working chambers ( 9 . 10 ; 11 . 12 ), and that via an actuator ( 23 ) switchable hydraulic valve ( 14 ) several worksports ( 18 . 19 . 20 ) and a P-port connected to a pressure source ( 16 ) and a tank-connected T-port ( 17 ) and in the rotor ( 3 ) a locking device ( 13 ), consisting of two axially adjustable, spring-loaded locking piston ( 25 . 26 ), which if necessary a relative movement between the rotor ( 3 ) and the stator ( 2 ), in which at least one locking piston ( 25 . 26 ) is displaceable from a first switching position counter to a spring force in a second switching position and at a rotation of the rotor ( 3 ) from a stop position EARLY or LATE in a center locking position (MVP) in a locking slot (FIG. 29 ), characterized in that each locking piston ( 25 . 26 ) of the locking device ( 13 ) an axial bore ( 36 . 37 ), which in a position match with a connecting line ( 32 . 33 ) each have a separate flow connection between the working chambers ( 7 . 8th ) of a pressure chamber ( 6a ). Camshaft adjuster ( 1 ) according to claim 1, characterized in that the center lock at a stop or a start of the internal combustion engine by switching the hydraulic valve ( 14 ) into a position ( 15a ), whereby the locking latches ( 29 ) with a C port ( 20 ) and the T-port ( 17 ) are connected and the hydraulic fluid flows out without pressure, wherein a connecting line ( 32 . 33 ) of which in the locking link ( 29 ) latched locking piston ( 25 . 26 ) is interrupted and the further unlocked locking piston ( 26 . 25 ) in a position match with the connecting line ( 33 . 32 ) an exchange of hydraulic fluid between the working chambers ( 7 . 8th ). Camshaft adjuster ( 1 ) According to one of the preceding claims, characterized in that the working chamber ( 7 . 8th ) via the connecting line ( 32 . 33 ), the axial bore ( 36 . 37 ) and a tap hole ( 46 . 47 ) in the locking piston ( 25 . 26 ), the locking link ( 29 ) and hydraulic lines ( 30 . 31 ) with the C port ( 29 ) connected is. Camshaft adjuster ( 1 ) according to one of the preceding claims, characterized in that during normal operation of the internal combustion engine both locking pistons ( 25 . 26 ) via the C port ( 20 ) of the hydraulic valve ( 14 ) is pressurized into the rotor ( 3 ) and thus unlocked. Camshaft adjuster ( 1 ) according to claim 4, characterized in that during normal operation of the internal combustion engine, the axial bores ( 36 . 37 ) of both locking pistons ( 25 . 26 ) as well as the associated connection lines ( 32 . 33 ) at an adjustment of the camshaft adjuster ( 1 ) an exchange of hydraulic fluid between the working chambers ( 7 . 8th ) or the chamber pairings of the pressure chamber ( 6a ) to ensure. Camshaft adjuster ( 1 ) according to one of the preceding claims, characterized in that each locking piston ( 25 . 26 ) of the locking device ( 13 ) a spring element ( 44a . 44b ) associated with the locking pistons ( 25 . 26 ) in the direction of the locking scenes ( 29 ) as soon as one of the locking pistons ( 25 . 26 ) impinging counterforce fails. Camshaft adjuster ( 1 ) according to one of the preceding claims, characterized in that the locking piston intended for locking in the direction of EARLY ( 25 ) in one of the rotor ( 3 ) extended locked position a flow of hydraulic fluid through the connecting line ( 32 ) between the working chambers ( 7 . 8th ) and the locking piston intended for locking in the LATE direction ( 26 ) in one of the rotor ( 3 ) extended locked position a hydraulic fluid flow of the connecting line ( 33 ) to the working chambers ( 7 . 8th ) interrupts. Camshaft adjuster ( 1 ) according to one of the preceding claims, characterized in that the camshaft adjuster ( 1 ) more than two symmetrically in the stator ( 2 ) introduced pressure chambers ( 6a . 6b . 6c ). Camshaft adjuster ( 1 ) according to one of the preceding claims, characterized in that to influence on a pressure ratio of the camshaft adjuster ( 1 ) the stator ( 2 ) indirectly or directly an additional one, the working chambers ( 7 . 8th ) reducing component ( 45 ) assigned.

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