DE102017126172B3 - Hydraulic camshaft adjuster - Google Patents

Abstract

The invention relates to a hydraulic camshaft adjuster (1), comprising a stator (2) in which a rotor (3) is rotatably arranged, wherein the stator (2) has at least one wing (4), wherein the wing (4) in a Hydraulic chamber (5) of the stator (2) is arranged so that a first sub-chamber (A) is separated from a second sub-chamber (B), a central valve (6), the flow of hydraulic fluid into the first sub-chamber (A) and in the second sub-chamber (B) controls a locking system (7, 8) with which the rotor (3) can be locked relative to the stator (2) in a central position (M), the locking system (7, 8) being a first control element (7) which can be held in an unlocked position by the application of hydraulic fluid (C) via the central valve (6) and which can cause a lock when the pressure of the hydraulic fluid is removed, the first control element (7) being provided with a guide (7). 9) brought into operative connection who can, which is formed in the stator (2) or a component connected thereto, wherein the link (9) determines an axial position (a) of the first control element (7), a hydraulic pump (P) for providing hydraulic fluid and a tank (T) for receiving hydraulic fluid. In order to approach the center position in a simple manner, the invention provides that the first control element (7) is fluidically connected to the second sub-chamber (B) at least outside the center position (M) and can assume two different hydraulic switching positions, namely a first switching position in that it blocks a connection of the second sub-chamber (B) to the tank (T), and a second switching position, in which it establishes a connection between the second sub-chamber (B) and the tank or directly from the camshaft adjuster (1) to the environment , 1

Description

Field of the invention

• - einen Stator, in dem ein Rotor drehbar angeordnet ist, wobei der Stator mindestens einen Flügel aufweist, wobei der Flügel in einer Hydraulikkammer des Stators angeordnet ist, so dass eine erste Teilkammer von einer zweiten Teilkammer getrennt wird,
• - ein Zentralventil, das den Strom von Hydraulikfluid in die erste Teilkammer und in die zweite Teilkammer steuert,
• - ein Verriegelungssystem, mit dem der Rotor relativ zum Stator in einer Mittenposition verriegelt werden kann, wobei das Verriegelungssystem ein erstes Steuerelement umfasst, das durch Beaufschlagung mit Hydraulikfluid über das Zentralventil in einer entsperrten Position gehalten werden kann und das bei Wegnahme des Drucks des Hydraulikfluids eine Verriegelung veranlassen kann, wobei das erste Steuerelement mit einer Kulisse in Wirkverbindung gebracht werden kann, die im Stator oder einem mit diesem verbundenen Bauteil ausgebildet ist, wobei die Kulisse eine axiale Lage des ersten Steuerelements bestimmt,
• - eine Hydraulikpumpe zur Bereitstellung von Hydraulikfluid und
• - einen Tank zur Aufnahme von Hydraulikfluid.

The invention relates to a hydraulic camshaft adjuster, comprising

• a stator in which a rotor is rotatably arranged, the stator having at least one vane, wherein the vane is arranged in a hydraulic chamber of the stator, so that a first sub-chamber is separated from a second sub-chamber,
• a central valve which controls the flow of hydraulic fluid into the first sub-chamber and into the second sub-chamber,
• a locking system with which the rotor can be locked relative to the stator in a central position, the locking system comprising a first control member which can be held in an unlocked position by the application of hydraulic fluid through the central valve, and the one upon removal of the pressure of the hydraulic fluid Lock can cause, wherein the first control can be brought into operative connection with a gate, which is formed in the stator or a component connected thereto, wherein the gate determines an axial position of the first control,
• a hydraulic pump for providing hydraulic fluid and
• - A tank for holding hydraulic fluid.

Background of the invention

A hydraulic camshaft adjuster of this kind is for example from the DE 10 2012 201 556 B4 known. Similar and other solutions show the DE 10 2012 201 570 A1 , the DE 10 2012 201 551 A1 , the US 2003/0 196 626 A1 the US 2011/0 017 156 A1 and the US 2013/0 220 253 A1 , Part of such cam phasers is to provide a locking function in the central position of the rotor blade in the hydraulic chamber, and this should be possible in a reliable and inexpensive manner.

It is known to design camshaft adjusters in such a way that with the aid of the camshaft alternating torques (ie on the basis of "CTA" = Cam Torque Activated; also available when the engine stops), the center position is also present when the engine stops or starts the internal combustion engine Rotor is pulled by means of a so-called hydraulic ratchet in the center position. The hydraulic ratchet is also combined with the so-called "smart phasing" function, as components for both functions can be used simultaneously, which provides cost advantages. This is also known as a "smart lock".

The aforementioned "Smart Lock" function provides cost advantages over a simple "Midlock" manufacturer. However, it is necessary for hydraulic oil in the rotor (as from the above DE 10 2012 201 556 B4 and from the DE 10 2012 201 570 A1 known) or by means of a collecting bell (as from the above DE 10 2012 201 551 A1 known) in the spring cover store. Since the stored oil can no longer be used for the hydraulic ratchet function due to the then high oil viscosity (and the resulting flow resistance through the check valve inlets of the vane), this is combined with a simple mechanical ratchet function. This then jumps as a "fail-safe" function, for example, when the engine was shut down after stalling unlocked and the oil then reaches a high viscosity at low ambient temperature.

The DE 10 2013 204 928 A1 shows a hydraulic camshaft phaser of the vane type, with a rotor and a stator and with a Hydraulikmittelleitsystem by means of which at least two separate by a rotor fixed wing chambers with a hydraulic fluid supply and / or Hydraulikmittelabführeinrichtung with the interposition of a hydraulic valve are connected or connected, wherein in the wing switchable hydraulic fluid control means is provided, which is adapted for selectively releasing and interrupting fluid communication from one chamber to another chamber, wherein a locking means for eliminating rotational movement between the rotor and the stator is present, wherein the locking means for locking the rotor to the stator in a sash position is designed, to which the two chambers have an approximately equal volume, and wherein the locking device gelan at least one in positive engagement with a stator-fixed component pin, such as a locking pin, wherein the pin is designed to control the inflow and / or outflow of hydraulic fluid to / from a chamber.

The DE 10 2013 219 078 A1 shows a hydraulic camshaft phaser of the vane type, with a stator and with a rotatably ordierierten rotatably angeordeten rotor, wherein the rotor and the stator at least two arranged between them and formed by a rotor-fixed wing working chambers, which are filled by a hydraulic fluid supply device with hydraulic fluid, wherein at least one locking pin is present, which rotatably sets the rotor in the locked state to the stator, wherein the Locking pin is connected to an active pressure accumulator deflecting it when necessary, wherein the locking pin and the active pressure accumulator are so interrelated that the locking pin is prevented from rotating the rotor relative to the stator. Disclosed is also a method for locking a rotor of a hydraulic camshaft adjuster relative to a stator of the camshaft adjuster, wherein at least one locking pin, the rotor is locked to the stator in a central position and additionally in an early or late position and a hydraulic means of one for filling used by working chambers between the rotor and the stator hydraulic medium supply device separate active pressure accumulator for acting on a longitudinal movement of the locking pin is used.

The DE 10 2014 206 853 A1 shows a camshaft adjuster, with a rotor which is rotatably disposed within a stator, and with at least one locking bolt, which is to prevent a relative rotation of the rotor to the stator, prepared for engagement in a gate of a statorfesten member, wherein the locking bolt at its near-stage End is conical, with the backdrop is stepped.

Object of the invention

The present invention is therefore the object of a generic camshaft adjuster in such a way that it is possible to approach the center position in a simple and reliable manner. Here, a simple construction is sought, which can be realized inexpensively.

Summary of the invention

The solution of this object by the invention is characterized in that the first control fluidly communicates with the second sub-chamber at least outside the center position and can assume two different hydraulic switching positions, namely a first switching position in which there is a connection of the second sub-chamber to the tank blocked, and a second switching position in which it establishes a connection between the second sub-chamber and the tank or directly from the camshaft adjuster to the environment.

The first control element preferably has no further switching positions in addition to the two switch positions mentioned.

According to the invention, the fluidic connection between the first control element and the second sub-chamber is interrupted in the middle position. For this purpose, it is provided that the interruption of the fluidic connection takes place in that a segment of the stator covers the flow path between the first control element and the second partial chamber.

In the second switching position, a connection between the second sub-chamber and the first sub-chamber is preferably additionally produced.

Preferably, a second control is also present, which has no influence on the flow of hydraulic fluid in the camshaft adjuster (it is accordingly a spring-biased control, which can only engage in the backdrop). It can be provided that the link in the stator or in a component connected to this has an extension in the circumferential direction, which corresponds to the distance between the two controls in the circumferential direction.

Furthermore, it can be provided that the gate for the entry of the first control has a recess further recessed.

The scenery is usually designed as a curved slot in the stator or a component connected to this.

The controls are preferably designed as a pin which is arranged against the bias of a spring in a bore in the rotor.

The central valve preferably has a switching position for locking the rotor in the middle position, in which the hydraulic pump is connected to the second sub-chamber and the first sub-chamber is connected to the tank.

The proposed concept accordingly uses the Nockenwellenreibmoment, which always acts in "late" direction. This is realized in a simple structure, which may optionally be used with minimal resources more chamber pairs for the center locking function. The optional use of the Smart Phasing function is retained.

The proposed concept reduces the complexity and costs compared to the previously known "smart lock" manufacturer and also offers the option of optionally using the "smart phasing" function.

list of figures

• 1 in perspektivischer Darstellung einen geöffnet (ohne Deckel des Stators) dargestellten Nockenwellenversteller in einer Ausführung mit Kurzschlussleitung, bei dem sich der Rotor relativ zum Stator in einer Mittenposition befindet,
• 2 in perspektivischer Darstellung einen Schnitt durch einen Teil des Nockenwellenverstellers mit dem ersten Steuerelement,
• 3 in perspektivischer Darstellung das erste Steuerelement (Steuerpin) im Rotor des Nockenwellenverstellers,
• 4 in perspektivischer Darstellung die Patrone des Steuerelements gemäß 3,
• 5 in perspektivischer Darstellung den Nockenwellenversteller,
• 6 in perspektivischer Darstellung einen Teil des geöffneten (ohne Deckel des Stators) Nockenwellenverstellers analog zu 1 in einer Ausführung ohne zusätzliche Kurzschlussleitung von der A- zur B-Kammer,
• 7 einen Radialschnitt durch den Nockenwellenversteller mit der Darstellung zweier Steuerelemente,
• 8 schematisch den Nockenwellenversteller mit seiner hydraulischen Versorgung, wobei der Verriegelungsvorgang in die Mittenposition aus einer „Spät“-Stellung dargestellt ist,
• 9 schematisch den Schnitt durch den Nockenwellenversteller, wobei der zu 8 korrespondierende Zustand gezeigt ist,
• 10 schematisch den Nockenwellenversteller mit seiner hydraulischen Versorgung, wobei der Verriegelungsvorgang in die Mittenposition aus einer „Früh“-Stellung dargestellt ist,
• 11 schematisch den Schnitt durch den Nockenwellenversteller, wobei der Rotor in der verriegelten Mittenposition befindet,
• 12 schematisch den Nockenwellenversteller mit seiner hydraulischen Versorgung, wobei ein alternatives Ausführungsbeispiel mit nur einem Steuerelement dargestellt ist,
• 13 schematisch den Nockenwellenversteller mit seiner hydraulischen Versorgung, ähnlich 8, aber mit Kurzschlussleitung wie in der Ausführung gemäß 1, wobei der Verriegelungsvorgang in die Mittenposition aus einer „Spät“-Stellung dargestellt ist,
• 14 schematisch den Nockenwellenversteller mit seiner hydraulischen Versorgung, ähnlich 10, aber mit Kurzschlussleitung wie in der Ausführung gemäß 1, wobei der Verriegelungsvorgang in die Mittenposition aus einer „Spät“-Stellung dargestellt ist,
• 15 schematisch den Nockenwellenversteller mit seiner hydraulischen Versorgung, wobei sich dieser im Normalbetrieb und in Richtung „Früh“ befindet, und
• 16 schematisch den Nockenwellenversteller mit seiner hydraulischen Versorgung, wobei sich der Rotor in der verriegelten Mittenposition befindet.

In the figures, embodiments of the invention are shown. Show it:

• 1 3 shows a perspective view of an open camshaft adjuster (without a cover of the stator) in a short-circuited embodiment in which the rotor is in a center position relative to the stator,
• 2 in a perspective view a section through a part of the camshaft adjuster with the first control element,
• 3 in a perspective view the first control element (control pin) in the rotor of the camshaft adjuster,
• 4 in perspective view of the cartridge of the control according to 3 .
• 5 in a perspective view the phaser,
• 6 in a perspective view a part of the open (without cover of the stator) camshaft adjuster analogous to 1 in an embodiment without additional short circuit line from the A to the B chamber,
• 7 a radial section through the camshaft adjuster with the representation of two controls,
• 8th 2 shows schematically the camshaft adjuster with its hydraulic supply, wherein the locking process is shown in the middle position from a "late" position,
• 9 schematically the section through the camshaft adjuster, wherein the 8th corresponding state is shown
• 10 2 shows schematically the camshaft adjuster with its hydraulic supply, wherein the locking process is shown in the middle position from an "early" position,
• 11 FIG. 2 schematically shows the section through the camshaft adjuster with the rotor in the locked center position. FIG.
• 12 1 schematically shows the camshaft adjuster with its hydraulic supply, wherein an alternative embodiment is shown with only one control element,
• 13 schematically the camshaft adjuster with its hydraulic supply, similar 8th , but with short circuit wire as in the design according to 1 wherein the locking operation is shown in the middle position from a "late" position,
• 14 schematically the camshaft adjuster with its hydraulic supply, similar 10 , but with short circuit wire as in the design according to 1 wherein the locking operation is shown in the middle position from a "late" position,
• 15 schematically the phaser with its hydraulic supply, which is in normal operation and in the direction of "early", and
• 16 schematically the phaser with its hydraulic supply, wherein the rotor is in the locked center position.

Detailed description of the figures

In 1 is a camshaft adjuster 1 shown that a stator 2 and a relative to this rotatable rotor 3 having. The rotor 3 has several wings 4 which is in respective hydraulic chambers 5 of the stator 2 extend and here in each case a first sub-chamber A from a second sub-chamber B separate. In regular operation of the camshaft adjuster 1 is by supplying hydraulic oil in the sub-chambers A respectively. B a desired relative rotational position between stator 2 and rotor 3 produced.

Hereinafter, only the new features of the hydraulic camshaft adjuster are shown, since the general operation of such a phaser is well known. For hydraulic control of such an element and in particular for controlling the adjuster with a central valve is expressly for example on the DE 10 2013 226 437 B4 the patent applicant, where detailed information is included.

In normal operation of the camshaft adjuster 1 Accordingly, the sub-chambers A and B supplied in the desired manner with hydraulic oil. A locking system 7 . 8th , is passive in this mode of operation, which is accomplished in that one C -Port - see the 15 - Pressure oil is passed. As a result, controls 7 . 8th such by means of the pressure of the hydraulic fluid against a spring 12 (S. 2 ) pressed the controls 7 . 8th take a non-locked position and thus the camshaft adjuster 1 is in his normal working position. In 2 and 3 is the control 7 with his cartridge 13 (S. 4 ) in the locked position, wherein a spring 12 on the cartridge 13 acts. Indicated here is the flow of hydraulic fluid from the sub-chamber B out to the tank T as well as in the direction of the sub-chamber A , The design of the cartridge 13 or the bore containing the cartridge allows the outflow of hydraulic fluid as in 3 shown. To control the flow of hydraulic fluid, the control moves 7 in an axial direction a ,

In the 3 to 7 For this purpose, various details are shown. Indicated here is the Outflow from the sub-chamber B (S. 3 ) and the vent to the tank (s. 3 and 5 ), which is relevant to the control of the system described below.

In the following 8th to 14 Explanations on how to proceed to the rotor 3 relative to the stator 2 in the middle position M to spend and lock there.

The locking itself takes place through a backdrop 9 placed in a lid of the stator 2 is incorporated. Once the pressure in the C-port has been removed and the prerequisite for locking is created, the controls can 7 . 8th with appropriate relative position between stator 2 and rotor 3 in the scenery 9 due to the action of the spring 12 engage and thus cause the lock. For this, however, the rotor must 3 first in the middle position M to be brought.

For this purpose, a central valve 6 in the in the 8th . 10 . 12 . 13 and 14 presented "Midlock" position. In this position, hydraulic fluid from the hydraulic pump P (via a check valve) through the central valve 6 in the sub-chamber B passed while at the same time the sub-chamber A to the tank T is switched. Also, of course, is the C-port to the tank T switched to locking the controls 7 . 8th to make possible.

It is essential that the first control 7 - at least outside the middle position M - Fluidic with the second sub-chamber B is in communication and can assume two different hydraulic switching positions, namely a first switching position in which there is a connection of the second sub-chamber B to the tank T blocked, and a second switching position in which there is a connection between the second sub-chamber B and the tank or directly from the phaser 1 to the environment manufactures.

This is off first 8th can be seen where the rotor 3 relative to the stator 2 is in a "late" position and accordingly for locking in the middle position M "Back" must be turned. In the solution shown here are two controls 7 and 8th provided, of which the first control 7 as mentioned above, the two switching positions, while the second control 8th only as a spring-biased pin (locking pin) is formed. How out 8th As can be seen, the second control is located 8th already in the area of the scenery 9 and is locked into it (after the C-port on the tank T is switched).

Meanwhile, there is the first control 7 still outside the scenery 9 , so that in the switching position caused thereby an interruption between the sub-chamber B and the tank T is made. This causes the hydraulic pump to transfer the hydraulic fluid to the subchamber B promotes and so the rotor 3 towards the center position M "Turned back" is. Once this is achieved, the first control 7 due to the action of the spring 12 in the scenery 9 engage, whereby the switching position is reached, in which the sub-chamber B on the tank T is switched.

In 8th as in 11 is with the reference numeral 10 a segment of the stator 2 marked when reaching the center position M via the fluid channel to the sub-chamber B pushes it and thereby interrupts the flow of hydraulic fluid (to avoid "chattering", details are noted below).

9 shows that according to the situation 8th corresponding relative position between rotor 3 and stator 2 ,

10 shows the situation when the rotor 3 relative to the stator 2 is in an "early" position and thus in order to reach the center position M Must be turned "forward". Here is the first control 7 already in the scenery 9 so that the sub-chamber B on the tank T is switched. Meanwhile, there is the second control 8th still outside the scenery 9 , By the derivation of the hydraulic fluid from the sub-chamber B (to the tank T ), the drag torque of the camshaft friction now suffices (see also the "Camshaft friction" in 1 ) to the rotor 3 "Forward" towards the center position M to move until the locking position for both controls 7 . 8th is reached and the lock can be made.

The locked state is in 11 and in addition to him 16 illustrated.

12 shows an alternative embodiment of the invention, with only a single control 7 gets along. This is designed as described above and has the two mentioned switch positions. In principle, this solution works as described above, now only in the scenery 9 a further recessed well 11 is incorporated for the control 7 offers a defined end position.

Accordingly, the backdrop has 9 in the locked position of the center position M of the remaining pin 7 the depression 11 , The pin 7 can then from "early" coming as described snap and coming from "late" briefly the center position M fly over and then fall behind and snap into place. However, in this case, the locking security is lower and unlocking according to the occurring Alternating moments more difficult as the pin 7 is clamped at one-sided pressure to the wall of the locking pin hole.

The 13 and 14 correspond largely to the 8th and 10 , where here is an additional line 14 is indicated to Rotornut. This ensures that the pressure of the sub-chamber B to the partial chamber A is balanced and more oil can be derived. This reduces the resistance to camshaft friction during midlock operation.

Thus, the following can be said in total:

The rotor 3 contains the known grooves, which are connected to the oil ports of the central valve 6 are connected: A port, B port and C port. The A-chambers act here in the direction of "late", the B-chambers in the direction of "early" (but with appropriate coil spring design or inverting the circuit this can also be exchanged cost-neutral). The camshaft friction torque always acts in the direction of "late", so it pushes the rotor blades onto the B chambers.

The camshaft adjuster 1 contains according to an embodiment of the invention, two equal, simple locking pins 7 . 8th (without grooves), which is inexpensive. One of the pins 7 In contrast to the previously known circuit has no connection to the Rotorölnuten, but only a connection directly to one of the B-chambers. This he can switch to the tank, with the oil directly from the adjuster 1 is dismissed. The other pin 8th has no hydraulic switching function (so it is not in connection with the oil-carrying cavities) and locked only mechanically.

The central valve 6 is similar in construction to previously known solutions, except that the sub-chamber A on the tank T is switched. The neighboring position P - B - A - T (Normal operation, adjustment direction "early") is thus retained for the basic position or for the center locking position. This allows a favorable construction of the central valve 6 , Of the C -Port also serves to activate the locking function. As long as the pressure in the C channel keeps a certain level, the switching pins are 7 . 8th always retracted and the camshaft adjuster is adjusted via the A and B ports. This is the normal working mode of the adjuster.

As soon as the current to the central magnet is set to a low duty cycle or the current is completely switched off (eg during engine stop), the spring of the central valve switches it to the switching position P - B - A - T with C on the tank T ,

The A Chambers are so to the tank T switched and empty or no longer provide pressure support. The hydraulic pump P supports the B-chamber. Of the C Channel is simultaneously deflated to T. The control pins 7 . 8th can now extend - depending on the rotor position. In the locking cover on one of the end faces of the stator 2 is located with the (now depressurized) C-channel connected locking link 9 (Slot in the circumferential direction).

Is the rotor located? 3 not in the middle position M but like in 9 shown in the direction of the B-chamber ("Late"), is the pin 7 that switches the B-chamber, not within the backdrop 9 and blocks the connection of the B-chamber to the tank T , This will be the rotor 3 rotated by the pump pressure in the direction of "early" against the camshaft friction. The adjuster operates as in normal operation and therefore with all chamber pairs. The switching pin 8th without hydraulic function prevents overshoot and strikes when reaching the center position M at the end of the shift gate 9 at. Both pins 7 . 8th are now in the backdrop 9 pressed and the position fixed positively.

Is the rotor located? 3 in the direction of the A-chamber ("Früh"), the B-switching switching pin 7 in the locking frame 9 pressed and opens the B-chamber to the tank T , The oil can be directly at the locking pin 7 escape from the camshaft adjuster (so does not go to the T-port of the central valve 6 ). About the ring grooves 15 in the rotor 3 (S. 5 ), all other B chambers are connected to the tank. The flow resistance is low despite the leadership of all chambers via a line, as it goes directly into the environment and therefore can be performed with a high cross-section. Thus, the hydraulic support of all B-chambers is deactivated. The A Chambers are connected via the central valve to the tank. Since now the hydraulic assistance is altogether deactivated, only the camshaft friction remains, which the phaser direction "late" to the middle position M pulls until both pins 7 . 8th engage.

The bore, which is the B chamber with the locking pin 7 (and thus depending on Pinschaltposition with the tank T ) is in the middle position M from the stator segment 10 covered (see 11 ). This is beneficial to keeping the connection in the center position M is interrupted again. Otherwise, the chambers would not fill at engine start, as the central valve 6 starts again in the center locking position and then the hydraulic pump P over the still locked pin 7 would be connected to the tank (see the schematic or abstract representation in 16 where this is denoted by the reference numeral 10 is indicated). If then switched to normal operation, the pins would 7 . 8th unlocked by the C-channel and the camshaft adjuster would bounce to inflate the chambers, which is known as "chattering".

Furthermore, the covering of the hole in the middle position M the positive side effect, the adjuster just before the opening of the locking pin at the end of the scenery 9 to dampen. A malfunction due to exceeding the stator segment after "late" and the opening of the A-chamber after T can not occur because the pin 7 here because of the locking block contour the T-connection has closed.

If the camshaft friction torque were not large enough, the proposed concept could also be used advantageously and in a simple manner as follows, when using a corresponding shift strategy: The central valve 6 Shortly before the engine stop, depending on the current adjustment position, it is briefly energized (ie without regulation), in order to bring the stage slightly behind the middle direction "Late" and then switches off the power. The stage then automatically switches to the middle position.

LIST OF REFERENCE NUMBERS

1

Phaser

2

stator

3

rotor

4

wing

5

hydraulic chamber

6

central valve

7, 8

locking system

7

first control (control pin)

8th

second control (control pin)

9

scenery

10

Segment of the stator

11

further recessed well in the scenery

12

feather

13

cartridge

14

additional short-circuit line from B to A Rotornut

15

rotor slot

A

first compartment

B

second sub-chamber

C

C-port for unlocking

P

hydraulic pump

T

tank

M

center position

a

axial direction

Claims (8)

A hydraulic phaser (1) comprising - a stator (2) in which a rotor (3) is rotatably mounted, said stator (2) having at least one vane (4), said vane (4) being mounted in a hydraulic chamber (5 ) of the stator (2) is arranged so that a first sub-chamber (A) is separated from a second sub-chamber (B), - a central valve (6), the flow of hydraulic fluid in the first sub-chamber (A) and in the second Partial chamber (B) controls, - a locking system (7, 8) with which the rotor (3) relative to the stator (2) in a center position (M) can be locked, wherein the locking system (7, 8) a first control ( 7) which can be held in an unlocked position by the application of hydraulic fluid via the central valve (6) and which can cause a lock when the pressure of the hydraulic fluid is removed, the first control element (7) being operatively connected to a link (9) can be brought into the stator (2) or a component connected thereto, wherein the link (9) determines an axial position (a) of the first control element (7), - a hydraulic pump (P) for providing hydraulic fluid and - a tank (T) for receiving hydraulic fluid , characterized in that the first control element (7) at least outside the center position (M) is fluidically connected to the second sub-chamber (B) and can assume two different hydraulic switching positions, namely a first switching position in which there is a connection of the second sub-chamber (B) to the tank (T) blocked, and a second switching position in which it establishes a connection between the second sub-chamber (B) and the tank or directly from the camshaft adjuster (1) to the environment, wherein the fluidic connection between the first control element (7) and the second sub-chamber (B) in the middle position (M) is interrupted and the interruption of the fluidic connection takes place by a Segme nt (10) of the stator (2) covers the flow path between the first control element (7) and the second sub-chamber (B). Hydraulic camshaft adjuster to Claim 1 , characterized in that in the second switching position in addition a connection between the second partial chamber (B) and the first partial chamber (A) is produced. Hydraulic camshaft adjuster according to one of the Claims 1 or 2 , characterized in that further comprises a second control element (8) is present, which has no influence on the flow of hydraulic fluid in the camshaft adjuster (1). Hydraulic camshaft adjuster to Claim 3 , characterized in that the link (9) in the stator (2) or in an associated with this component has an extension in the circumferential direction, which corresponds to the distance between the two control elements (7), (8) in the circumferential direction. Hydraulic camshaft adjuster according to one of the Claims 1 to 4 , characterized in that the link (9) for the entry of the first control element (7) has a recessed further recess (11). Hydraulic camshaft adjuster according to one of the Claims 1 to 5 , characterized in that the link (9) is formed as a curved slot in the stator (2) or a component connected thereto. Hydraulic camshaft adjuster according to one of the Claims 1 to 6 , characterized in that the control elements (7), (8) are designed as a pin which is arranged against the bias of a spring (12) in a bore in the rotor (3). Hydraulic camshaft adjuster according to one of the Claims 1 to 7 , characterized in that the central valve (6) has a switching position for the locking of the rotor (3) in the middle position (M), in which the hydraulic pump (P) connected to the second sub-chamber (B) and the first sub-chamber (A) is switched to the tank (T).

Images