EP3219941B1 - Hydraulic slider valve for a vane cell camshaft adjuster for a camshaft - Google Patents

Description

Technical area

The invention relates to a hydraulic valve, in particular for a Schwenkmotorversteller a camshaft of an internal combustion engine of a motor vehicle.

State of the art

From the DE 60 2005 000 504 T2 For example, a hydraulic valve is known in which a variable cam timing phaser has a piston, a plurality of check valves and channels from the feed chamber and the retard chamber to an opening in the spool. The piston, which has at least two slide bodies separated by a central rod, is displaceably mounted within a bore in the rotor. When the piston is in the first position, hydraulic fluid flows from the feed chamber through the passage and the opening to the bore surrounding the central rod of the spool and through a check valve and the port to the passage to the retard chamber. When the piston is in the second position, hydraulic fluid from the retard chamber flows through the passage and the aperture to the bore surrounding the central rod of the spool and through a check valve and the port to the passage to the feed chamber.

From the EP 3 219 941 A1 and from the EP 2 1977 569 A1 a generic hydraulic valve is known, which has a phase check valve in the interior of the piston. The piston has a phase volume in a bore and a fluid volume which is fluidly separated from it. Depending on the piston position, the phase check valve allows a fluid exchange between chambers of a camshaft adjuster.

Check valve sealed off and blocked against inflowing hydraulic fluid. The check valve thus prevents a pressure surge movement of the piston of the hydraulic valve.

Through this function of a check valve in the interior of the piston, a better control quality of the hydraulic valve can be combined with a particularly compact and cost-effective design of the hydraulic valve. Also, the risk of the flow of hydraulic fluid being blocked by the check valve is reduced. Such a check valve with a band-like flexible element opens better than comparable check valves and closes faster. The hydraulic valve can effectively implement by such a check valve occurring moments by pulsed hydraulic pressure and use for the function of the connected camshaft adjuster.

According to the invention, a check valve in the interior of the piston is assigned to each of the first working connection and the second working connection. In this way, each associated check valves can be opened inwardly by pressure pulses both on the first working port and on the second working port and so the pressure pulses are forwarded to the second or the first working port to the function of the alternating torques so low for the adjustment of the camshaft adjuster exploit.

There is provided a first operating position of the hydraulic valve in which a first fluid path of the hydraulic fluid from the first working port is open to the second working port via the check valve associated with the first working port, and a second operating position in which a second fluid path of the hydraulic fluid is provided second working port is open via the second working port associated check valve to the first working port. As a result, in the first operating position of the hydraulic valve, the hydraulic pressure can be passed directly from the first working port to the second working port, while in the second operating position the hydraulic pressure is directly from the second
Piston prevailing hydraulic pressure, in particular a pulse-like hydraulic pressure, can be opened inwardly.

Pulsed hydraulic pressures are on the one hand alternating moments on the hydraulic piston, which both temporarily have a positive, variable component and a temporary negative component. By contrast, swelling moments are those moments which, although they change in magnitude, remain over a longer period of several milliseconds in the same sign range of the torque characteristic.

On a motor hydraulic circuit of a camshaft adjuster with a counter-rotating hydraulic piston with at least two hydraulic chambers acts an external moment that acts either changing or swelling. The hydraulic circuit performs, by a hydraulic pump removable, different pressurization of the counter-rotating hydraulic chambers a change in position. In addition to a hydraulic Weichenverstellung, preferably embodied by a valve which directs the pressurization of the hydraulic fluid to the piston, the negative portion of the alternating torque is used to change the hydraulic piston in position. The swelling portion of the moment, however, is hidden by other means, such as check valves. The selective use of moments, in particular by the release via check valves, leads to a linearization of the adjustment speed over the speed of the engine, while the continued use of the smallest possible hydraulic supply from a pump for adjusting the piston ensures the high adjustment even with pure Schwellanteilen the moment ,

For example, each hydraulic connection paths can be provided from a chamber of one type to the working port for the other type of chamber. This results in a hydraulic circuit with a valve. The valve can pass the hydraulic pressure, since it is possible to divert the negative portion of the alternating torque on the one working connection for one chamber type via at least one check valve to the second working connection of the other type of chamber. It can be done alternately. Incidentally, the Pressurization of the pressurized port forwarded to the second working port. The alternate passage of the hydraulic medium is carried out from both the one chamber and the other chamber to the corresponding counter-rotating chamber. The function of the check valves can be referred to as a bypass, which feed only the negative part of the alternating force in front of the camshaft adjuster again. A suitable place of re-injection may be the supply connection of the camshaft adjuster. The check valve, or if there are a plurality of check valves, the check valves, can then be arranged so that only in the direction of the pressure side of the camshaft adjuster a passage of the hydraulic pressure originating from the chambers of the piston, is made possible.

The at least one check valve of the hydraulic valve is arranged in an inner region of the piston in order to allow the most compact possible construction of the hydraulic valve. In particular, the check valve is designed as a band check valve, which comprises a band-like flexible element, for example an annular, overlapping band of spring steel, as a closing element of the check valve. Such a flexible band has the necessary spring tension to oppose against hydraulic pressure from the outside a resistance, so that the band yields only when a certain pressure threshold is exceeded, can bend inwards and opens the valve cross-section. The pressure threshold can be adjusted by selecting the material and the thickness of the material. The inside of the piston constitutes an outer stop for the band against which the band bears, as long as the hydraulic pressure is below the threshold pressure, and the check valve is thus closed. When the pressure threshold is exceeded, the band lifts off from the stop inwardly, and opens the valve cross-section inwardly, so that hydraulic fluid can flow from an outer side of the piston into the inner region.

Characterized in that the check valve is opened by the hydraulic pressure of the chamber to be emptied of the camshaft adjuster inwardly, the hydraulic pressure is maintained in the chamber to be emptied. The chamber to be emptied is so through the Check valve sealed off and blocked against inflowing hydraulic fluid. The check valve thus prevents a pressure surge movement of the piston of the hydraulic valve.

Through this function of a check valve in the interior of the piston, a better control quality of the hydraulic valve can be combined with a particularly compact and cost-effective design of the hydraulic valve. Also, the risk of the flow of hydraulic fluid being blocked by the check valve is reduced. Such a check valve with a band-like flexible element opens better than comparable check valves and closes faster. The hydraulic valve can effectively implement by such a check valve occurring moments by pulsed hydraulic pressure and use for the function of the connected camshaft adjuster.

According to an advantageous embodiment, the first working port and the second working port may each be assigned a check valve in the interior of the piston. In this way, each associated check valves can be opened inwardly by pressure pulses both on the first working port and on the second working port and so the pressure pulses are forwarded to the second or the first working port to the function of the alternating torques so low for the adjustment of the camshaft adjuster exploit.

According to an advantageous embodiment, a first working position of the hydraulic valve may be provided, in which a first fluid path of the hydraulic fluid from the first working port via the first working port associated check valve to the second working port is open, and a second working position may be provided, in which a second fluid path the hydraulic fluid from the second working port is open to the first working port via the check valve associated with the second working port. As a result, in the first operating position of the hydraulic valve, the hydraulic pressure can be passed directly from the first working port to the second working port, while in the second operating position the hydraulic pressure is directly from the second Work connection can be passed to the first work connection, which is advantageous for a fast control behavior of the hydraulic valve.

According to an advantageous embodiment, a third, so-called center position of the hydraulic valve may be provided, in which the first working port and the second working port are closed independently of the check valves and are not connected to the check valves. In this center position so that the check valves and the chambers of a connected camshaft adjuster are closed and sealed off from each other. This third position thus corresponds to a control position or middle position of the hydraulic valve.

According to an advantageous embodiment, a further fluid path of the hydraulic fluid can be provided from the outside of the piston to the at least one check valve via bores in the piston. The hydraulic fluid can press on the holes in the wall of the piston on the ribbon-like flexible element of the check valve and thus open the check valve inwards. In this way, the band can abut against the stop on the inside of the piston and is pressed only by hydraulic pressure from outside to inside and thereby opened.

According to an advantageous embodiment may be provided at least partially on the outside of the piston radially circumferential cam for supplying the holes with hydraulic fluid. This can be ensured that the attacking hydraulic pressure acts radially circumferentially in the same way on the outside of the piston and the hydraulic pressure no rotation of the piston is initiated. About the control groove, the hydraulic pressure can then be passed through the holes in the wall of the piston on the tape of the check valve and actuate this.

According to an advantageous embodiment, the outer side of the piston in the region of the bores may be configured in each case partially as a flat surface. In an alternative embodiment, the outer side of the piston may be designed in sections as flat surfaces, which flattenings of the cylindrical outer wall represent of the piston, which adjoin each other circumferentially. The area values are conveniently balanced so that the piston is not rotated or moved axially by hydraulic pressure applied. Advantageously, a bore for supplying the check valve with the hydraulic pressure is provided in each area.

According to an advantageous embodiment, the band-like flexible element may be secured against displacement in the longitudinal direction by means of a fixation element comprising the element axially. The band-like flexible member is thus held axially in one position and can move only radially through the hydraulic pressure applied to open the check valve inwardly or close by re-applying to the inside of the piston. Thus, the check valve is fixed as a whole in the interior of the piston.

According to an advantageous embodiment, the check valve may be formed with at least one sleeve as an integrated unit which comprises the band-like flexible element and the fixing element, wherein the band-like flexible element biased against an inner side of the sleeve. In this way, the check valve can be pre-assembled as a mounting unit and particularly easy to arrange in the interior of the piston in the axially desired position. As a result, the stop of the band-like flexible element, depending on the design of the band, at least be predetermined by the inside of the sleeve. The assembly of the check valve in the piston is very favored by this solution. Advantageously, two sleeves may be provided which comprise the band from both sides in the longitudinal direction.

According to an advantageous embodiment, the band-like flexible element can be secured in a bore of the piston arranged with at least one annular fixing element against displacement in the longitudinal direction. Alternatively, it is also possible that the band is arranged directly in the interior of the piston and is fixed only by a fixing element in the axial direction, so that the band also in the function as a check valve when it is pressed inward, do not move axially can. For this purpose, the annular fixing element is equipped with a certain thickness or with radially extending fixing elements and / or still has an inner stop, which prevents the band beyond the annular fixing element can still move axially.

According to an advantageous embodiment, the fixing element may be cylindrical or hollow cylinder-shaped and axially spaced two areas with radially projecting projections, wherein the band-like flexible member is disposed around the fixing member and between the two areas and is axially fixed by the projections on the fixing element. These radially projecting projections may be configured in the form of webs or serrations which axially fix the band and are radially outward or inward in the longitudinal direction before and after the band. Already a lead before and after the band can fulfill this function. For reasons of symmetry, it is advantageous to provide three or more projections on the fixing element.

According to an advantageous embodiment, the fixing element can form a stop for the band-like flexible element inwards. The stop inwards can cause a limitation of the effective hydraulic pressure, which is forwarded from one working port to the other work port. Also, such a stable mounting of the band-like flexible element in the integrated unit of the check valve is favored and the position of the band is maintained even at higher pressure surges.

According to an advantageous embodiment, the radially projecting projections may be provided for supporting the at least one sleeve. The sleeve can be held by the radially projecting projections in the axial direction and supported in the radial direction, which favors the formation of a mounting unit for the check valve. Thus, the fixing element in the sleeve itself is firmly anchored.

According to an advantageous embodiment, a further check valve may be provided with a band-like flexible element at the supply connection within the piston, wherein the further check valve can be opened inwardly by a hydraulic pressure prevailing at the supply connection. Such a check valve on the supply connection can ensure that the Supply pressure of the hydraulic fluid is kept constant and any pressure surges from the working ports not penetrate the supply port, but at most can cause a drain of the hydraulic fluid in the tank drain.

The invention relates in another aspect to a Schwenkmotorversteller a camshaft comprising a hydraulic valve, wherein a first working port is connected to a first pressure chamber of the Schwenkmotorverstellers and a second working port is connected to a second pressure chamber of the Schwenkmotorverstellers. The first working connection and the second working connection can be connected by displacing the piston via at least one check valve alternately with one another and / or with the supply connection and / or with the at least one tank outflow. The at least one check valve is arranged in an inner region of the piston. The check valve comprises a band-like flexible member and, in an open position, releases communication between an outer side of the piston and the inner portion thereof, an inner side of the piston having an outer stopper for the check valve, so that the member is dominated by an outer side of the piston Hydraulic pressure, in particular a pulse-like hydraulic pressure, can be opened inwardly.

The hydraulic valve is intended to pass through the torque fluctuations, which can occur both as alternating torques and as swelling moments, with the hydraulic pressure from the supply connection, in particular in the case of the pivoting motor-like camshaft adjuster. Working connections that lead to the chambers of the hydraulic piston, depending on the switching position of the hydraulic piston within the valve alternately switched through or interrupted. Without torque fluctuations, the valve temporarily directs the hydraulic pressure in one of the chambers of the Schwenkmotorverstellers. In the hydraulic circuit creates another hydraulic pressure, which comes from the negative portion of the alternating torque. The hydraulic pressure resulting from the negative portion of the alternating torque is always at least via a check valve ausleitbar. The discharged pressure is passed on to the second working connection. The described condition is a special condition because most of the time the pressurization of the Supply connection is derived, is forwarded to the appropriate work connection. There is a wider use of pressures within the hydraulic circuit beyond the steady-state pressure. The bypass line resulting from the check valve takes advantage of the negative moment, while the standard adjustment is ensured by the selected standard position of the hydraulic piston. In addition to an advantageous energetic use of additional pressure resources, the feedback quality and even the adjustment speed are evened out or improved by this feedback.

In particular, for passing the negative portion of the alternating torque two check valves are used. The check valves are arranged to prevent hydraulic fluid flow from the supply port to the working port when the pressure resulting from the amount of the negative portion of the alternating torque exceeds the absolute pressure of the supply port. The valves work as directional throttles, so to speak.

Brief description of the drawings

Further advantages emerge from the following description of the drawing. In the drawings, embodiments of the invention are shown. The drawings, the description and the claims contain numerous features in combination. The person skilled in the art will expediently also consider the features individually and combine them into meaningful further combinations.

They show by way of example:

Fig. 1

a hydraulic valve for adjusting a Schwenkmotorverstellers according to an embodiment of the invention in a first working position, shown in a longitudinal section;

Fig. 2

the hydraulic valve according to FIG. 1 in a middle position;

Fig. 3

the hydraulic valve according to FIG. 1 in a second working position;

Fig. 4

a check valve according to an embodiment of the invention in a closed function, shown in a longitudinal section;

Fig. 5

the check valve according to FIG. 4 in an exploded view;

Fig. 6

the check valve according to FIG. 4 in open function, shown in a longitudinal section;

Fig. 7

a hydraulic valve according to another embodiment of the invention, shown in a longitudinal section;

Fig. 8

a hydraulic valve according to another embodiment of the invention, shown in a longitudinal section;

Fig. 9

a piston of a hydraulic valve according to an embodiment of the invention in an isometric view;

Fig. 10

a piston of a hydraulic valve according to another embodiment of the invention in an isometric view; and

Fig. 11

a Schwenkmotorversteller according to an embodiment of the invention in a cross section.

Embodiments of the invention

In the figures, the same or similar components are numbered with the same reference numerals. The figures are merely examples and are not intended to be limiting.

FIG. 1 shows a hydraulic valve 12 for adjusting a Schwenkmotorverstellers 14 according to an embodiment of the invention in a first operating position 54, shown in a longitudinal section. The hydraulic valve 12 comprises a bushing 15 with a piston 44 displaceably arranged in a bore 42 along a longitudinal direction L. The piston 44 is supported on the bush 15 by a helical compression spring 24.

The bushing 15 has a supply port 30 for supplying a hydraulic fluid, a first working port 34 and a second working port 36, and two tank outlets 38, 40 for discharging the hydraulic fluid. The first working port 34 and the second working port 36 can be connected by displacing the piston 44 via at least one check valve 46, 48 alternately with each other and / or with the supply port 30 and / or with the at least one tank drain 38, 40. The two check valves 46, 48 are arranged in the inner region 64 of the piston 44. The check valves 46, 48 comprise a band-like flexible element 80, which in an open position, a connection between the outer side 66 of the piston 44 and the inner region 64 releases. The inside 65 of the piston 44 has an outer stop for the check valves 46, 48, so that the element 80 can be opened inwardly by a hydraulic pressure prevailing on the outside 66 of the piston 44, in particular a pulse-like hydraulic pressure. A check valve 46, 48 in the inner region 64 of the piston 44 is assigned to each of the first working connection 34 and the second working connection 36. At the supply port 30, a further check valve 32 is provided with a belt-like flexible member 94 within the piston 44. This check valve 32 can also be opened inwardly by means of a hydraulic pressure prevailing at the supply connection 30. The band-like flexible element 94 is in this non-return valve 32 in the non-pressurized state in which the check valve 32 is closed, on the inner wall 20 of the sleeve 15 at.

The check valve 46, 48 has a fixing element 82, which is designed as a hollow cylinder with laterally projecting projections 92. The ribbon-like flexible element 80 is axially fixed between the projections 92 and can only move radially. Two sleeves 84 comprise the fixing element 82 from both ends and are supported by the projections 92, wherein the band-like flexible member 80 biased partially against the inner side 88 of the sleeve 84 and so the non-return valve 46, 48 closes. The check valve 46, 48 is designed as a preassembled integrated unit 86, which can be mounted as a whole low in the inner region 64 of the piston 44.

In FIG. 1 the hydraulic valve 12 is shown in a first operating position 54, in which a first fluid path 52 of the hydraulic fluid from the first working port 34 via the non-return valve 46 associated with the first working port 34 to the second working port 36 is open. The check valve 46 can be opened by the pending at the first working port 34 hydraulic pressure. In the drawing of FIG. 1 However, the check valve 46 itself is shown in the closed state with adjacent band-like flexible element 80. Also, the fluid path 74 from the supply port 30 via the inner region 64 of the piston 44 to the second working port 36 is open.

FIG. 2 shows the hydraulic valve 12 according to FIG. 1 in a middle position 57, in which the first working port 34 and the second working port 36 are closed independently of the check valves 46, 48. Both working ports 34, 36 are closed by the control piston 44, so that thereby there is no connection between the two working ports 34, 36 and the check valves 46, 48.

In FIG. 3 is the hydraulic valve 12 according to FIG. 1 in a second operating position 56, in which a second fluid path 72 of the hydraulic fluid from the second working port 36 via the second working port 36 associated check valve 48 to the first working port 34 is open. The check valve 48 can be opened by the pending at the second working port 36 hydraulic pressure. In the drawing of FIG. 3 However, the check valve 48 itself is shown in the closed state with adjacent band-like flexible element 80. Also, the fluid path 74 from the supply port 30 via the inner region 64 of the piston 44 to the first working port 34 is open.

FIG. 4 shows a check valve 46 according to an embodiment of the invention in a closed function, shown in a longitudinal section. The check valve 46 has the fixing element 82, which may be cylindrical or hollow cylindrical in shape (in FIG FIG. 4 it is hollow cylinder-shaped) and axially spaced two areas with radially projecting projections 92 has. The ribbon-like flexible member 80 is disposed around the fixing member 82 and between the two portions, and fixed axially on the fixing member 82 by the projections 92. The band-like flexible element 80 is secured with the element 80 axially comprehensive fixation element 82 against displacement in the longitudinal direction L.

Two sleeves 84 comprise the fixing element 82 from both ends and are supported by the projections 92, wherein the band-like flexible member 80 biased partially against the inner side 88 of the sleeve 84 and so the non-return valve 46, 48 closes. The check valve 46, 48 is designed as a preassembled integrated unit 86, which can be mounted as a whole low in the inner region 64 of the piston 44. The band-like flexible element 80 is biased on the inside 88 of the sleeves 84 and can be opened by hydraulic pressure from the outside. The fixing element 82 forms a stop for the band-like flexible element 80 inwards.

FIG. 5 shows the check valve 46 according to FIG. 4 in an exploded view. The individual components of the check valve 46 are shown separately according to a mounting sequence: the fixing member 82 as a central component of the check valve 46, the ribbon-like flexible member 80 which is positioned between the projections 92 of the fixing member 82 and the two sleeves 84, which subsequently on the Projections 92 of the fixing element 82 are pushed from both ends. The ribbon-like flexible element 80 is pressed to something inside, so that the element 80 biased against the inside 88 of the sleeves 84 and closes the check valve 46 in a pressureless state. It is in the embodiment in FIG. 5 each three projections 92 are shown equally distributed over the circumference of the fixing element 82, but it can also each four and more projections 92 may be arranged. Less than three projections 92 is also possible as long as the sleeves 84 can thus be supported on the fixing element 82.

In FIG. 6 is the check valve 46 according to FIG. 4 shown in an open function in a longitudinal section. The band-like flexible element 80 is pressed inwardly by externally applied hydraulic pressure and rests on the inner stop of the fixing element 82. The thus opened fluid paths 52 are in FIG. 6 shown with. The upper two fluid paths 52 in the drawing are shown in dashed lines, since they extend in front of or behind the plane of the drawing, since the projections 92 are cut in the plane of the drawing.

FIG. 7 shows a hydraulic valve 12 according to a further embodiment of the invention, shown in a longitudinal section. In this hydraulic valve 12, two check valves 46, 48 are used, which only have a band-like flexible element 80 which is secured in the bore 50 of the piston 44 with at least one annular fixing element 90 against displacement in the longitudinal direction L. The band-like flexible element 80 is biased in this embodiment in unpressurized, ie closed state of the check valve 46, 48 directly on the inside 65 of the inner region 64 of the piston 44 on one side to a stop of the bore 50 and is through the annular fixing element 90th , which is for example pressed into the bore 50, secured against displacement in the longitudinal direction L.

In FIG. 8 a hydraulic valve 12 is shown according to a further embodiment of the invention in a longitudinal section. The check valves 46, 48 have fixing elements 82 similar to those in the FIGS. 4 to 6 illustrated check valve 46, in which the ribbon-like flexible member 80 is disposed between axially spaced projections 92. In this embodiment, however, no sleeves 84 are used, the fixing element 82 is pressed directly into the bore 50 of the inner portion 64 of the piston 44, so that the ribbon-like flexible member 80 in the unpressurized, ie closed state of the check valve 46, 48 biased directly on the inside 65 of the inner region 64 is present.

FIG. 9 shows a piston 44 of a hydraulic valve 12 according to an embodiment of the invention in an isometric view. The piston 44 has bores 62 for the hydraulic connection of the outer side 66 of the piston 44 with the inner region 64. Further, the piston 44 has bores 60 which form a further fluid path 75 of the hydraulic fluid from the outer side 66 of the piston 44 to the check valves 46, 48 in FIG Provide piston 44. Through these holes 60 arranged in the inner region 64 of the piston 44 check valves 46, 48 are acted upon by the hydraulic pressure. Since the piston 44 in the bore 42 of the sleeve 15 of the hydraulic valve 12 is fitted, a at least partially on the outer side 66 of the piston 44 radially encircling control groove 68 is provided for supplying the holes 60 with hydraulic fluid, so that the hydraulic fluid on the outside 66 of the Piston 44 can penetrate via the cam 68 in the holes 60.

FIG. 10 shows a piston 44 of a hydraulic valve 12 according to another embodiment of the invention, in which the hydraulic supply of the holes 60 is provided in other ways. In this embodiment, the outer side 66 of the piston 44 in the region of the bores 60 in each case partially configured as a flat surface 70. The flat surfaces 70 are each provided coextensive, so that when pressurized thereby no unwanted movement of the piston 44 is triggered.

FIG. 11 shows a Schwenkmotorversteller 14 of a camshaft 18 in a cross section. The Schwenkmotorversteller 14 is for cooperation with a example in the FIGS. 1 to 3 illustrated hydraulic valve 12, wherein a first working port 34 is connected to a first pressure chamber 9 of the Schwenkmotorverstellers 14 and a second working port 36 is connected to a second pressure chamber 10 of the Schwenkmotorverstellers 14. In this case, the first working port 34 and the second working port 36 by a displacement of the piston 44 via at least one check valve 46, 48, as shown in the FIGS. 4 to 6 is shown, alternately with each other and / or with the supply port 30 and / or with the at least one tank outlet 38, 40th connectable. The at least one check valve 46, 48 is arranged in an inner region of the piston 44. The check valve 46, 48 includes a band-like flexible member 80 and, in an open position, communicates between an outer side 66 of the piston 44 and its inner portion 64, with an inner side 65 of the piston 44 having an outer stop for the check valve 46, 48. so that the element 80 can be opened inwardly by a hydraulic pressure prevailing on an outer side 66 of the piston 44, in particular a pulse-like hydraulic pressure.

With a Schwenkmotorversteller 14 according to FIG. 11 During operation of an internal combustion engine, the angular position on the camshaft 18 is changed continuously with respect to a drive wheel 2. By turning the camshaft 18, the opening and closing times of the gas exchange valves are shifted so that the internal combustion engine at the respective speed its optimum performance. brings. The Schwenkmotorversteller 14 has a cylindrical stator 1 which is rotatably connected to the drive wheel 2. In the exemplary embodiment, the drive wheel 2 is a sprocket over which a chain, not shown, is guided. The drive wheel 2 may also be a toothed belt wheel, via which a drive belt is guided as a drive element. About this drive element and the drive wheel 2, the stator 1 is drivingly connected to the crankshaft.

The stator 1 comprises a cylindrical stator base body 3, on the inside of which protrude webs 4 at equal intervals radially inwardly. Between adjacent webs 4 gaps 5 are formed, in, for example, via a in the FIGS. 1 to 3 controlled hydraulic valve 12 shown controlled, hydraulic fluid is introduced. The hydraulic valve 12 is designed as a decentralized valve, but can also be designed in one embodiment as a central valve. Between adjacent webs 4 protrude wings 6, which project radially outward from a cylindrical rotor hub 7 of a rotor 8. These wings 6 divide the spaces 5 between the webs 4 in each case in two pressure chambers 9 and 10th

The webs 4 lie with their end faces sealingly against the outer circumferential surface of the rotor hub 7. The wings 6 in turn lie with their end faces sealingly against the cylindrical inner wall of the stator main body 3.

The rotor 8 is rotatably connected to the camshaft 18. In order to change the angular position between the camshaft 18 and the drive wheel 2, the rotor 8 is rotated relative to the stator 1. For this purpose, depending on the desired direction of rotation, the hydraulic fluid in the pressure chambers 9 or 10 is pressurized, while the respective other pressure chambers 10 or 9 are relieved to the tank of the hydraulic fluid out. In order to pivot the rotor 8 counterclockwise relative to the stator 1 into the illustrated position, an annular first rotor channel in the rotor hub 7 is pressurized by the hydraulic valve 12. From this first rotor channel then lead further channels 11 in the pressure chambers 10. This first rotor channel is assigned to the first working port 34. In contrast, in order to pivot the rotor 8 in a clockwise direction, the hydraulic valve 12 pressurizes a second annular rotor channel in the rotor hub 7. This second rotor channel is associated with the second working port 36. These two rotor channels are arranged with respect to a central axis 22 axially spaced from each other.

The Schwenkmotorverstellers 14 is placed on the designed as a hollow tube 16 built camshaft 18th For this purpose, the rotor 8 is placed on the camshaft 18. The Schwenkmotorversteller 14 is by means of in FIG. 2 pivotable hydraulic valve 12 visible.

Claims (13)

1. Hydraulic valve (12), in particular for a pivoting motor adjuster (14) of a camshaft (18), comprising

   - a sleeve (15) having a piston (44) which is arranged so as to be displaceable in a bore (42) along a longitudinal direction (L),

   - a supply port (30) for feeding in a hydraulic fluid,

   - at least a first work port (34) and a second work port (36), and

   - at least one tank outlet (38, 40) for discharging the hydraulic fluid,

   wherein the first work port (34) and the second work port (36) can be connected in an alternating manner to one another and/or to the supply port (30) and/or to the at least one tank outlet (38, 40) by means of a displacement of the piston (44) via at least one non-return valve (46, 48),
   wherein the at least one non-return valve (46, 48) is arranged in an inner region (64) of the piston (44), which non-return valve (46, 48) comprises a strip-like flexible element (80) and, in an opened position, releases a connection between an outer side (66) of the piston (44) and the inner region (64) thereof, wherein an inner side (65) of the piston (44) has an outer stop for the non-return valve (46, 48), with the result that the element (80) can be inwardly opened by means of a hydraulic pressure prevailing on the outer side (66) of the piston (44), in particular a pulse-like hydraulic pressure, characterized in that the first work port (34) and the second work port (36) are each assigned a non-return valve (46, 48) in the inner region (64) of the piston (44), and a first working position (54) of the hydraulic valve is provided in which a first fluid path (52) of the hydraulic fluid is open from the first work port (34) to the second work port (36) via the non-return valve (46) assigned to the first work port (34), and a second working position (56) is provided in which a second fluid path (72) of the hydraulic fluid is open from the second work port (36) to the first work port (34) via the non-return valve (48) assigned to the second work port (36).
2. Hydraulic valve according to Claim 1, wherein a central position (57) of the hydraulic valve is provided in which the first work port (34) and the second work port (36) are closed independently of the non-return valves (46, 48).
3. Hydraulic valve according to one of the preceding claims, wherein a further fluid path (75) of the hydraulic fluid is provided from the outer side (66) of the piston (44) to the at least one non-return valve (46, 48) via bores (60) in the piston (44).
4. Hydraulic valve according to Claim 3, wherein a control groove (68) which extends at least partially radially around on the outer side (66) of the piston (44) and is intended for supplying the bores (60) with hydraulic fluid is provided.
5. Hydraulic valve according to Claim 3, wherein, in the region of the bores (60), the outer side (66) of the piston (44) is in each case configured in certain regions as a planar surface (70).
6. Hydraulic valve according to one of the preceding claims, wherein the strip-like flexible element (80) is secured against displacement in the longitudinal direction (L) by a fixing element (82) which axially encompasses the element (80).
7. Hydraulic valve according to Claim 6, wherein the non-return valve (46, 48) is formed with at least one sleeve (84) as an integrated unit (86) which encompasses the strip-like flexible element (80) and the fixing element (82), wherein the strip-like flexible element (80) bears in a preloaded manner against an inner side (88) of the sleeve (84).
8. Hydraulic valve according to one of Claims 1 to 5, wherein the strip-like flexible element (80) is arranged in a bore (50) of the piston (44) so as to be secured by at least one annular fixing element (90) against displacement in the longitudinal direction (L).
9. Hydraulic valve according to one of Claims 6 to 8, wherein the fixing element (80) is cylindrical or hollow-cylindrical and has, axially spaced apart from one another, two regions with radially protruding projections (92), wherein the strip-like flexible element (80) is arranged around the fixing element (82) and between the two regions and is fixed axially on the fixing element (82) by means of the projections (92).
10. Hydraulic valve according to one of Claims 6 to 9, wherein the fixing element (82) inwardly forms a stop for the strip-like flexible element (80).
11. Hydraulic valve according to one of Claims 6 to 10, wherein the radially protruding projections (92) are provided to support the at least one sleeve (84).
12. Hydraulic valve according to one of the preceding claims, wherein a further non-return valve (32) having a strip-like flexible element (94) is provided at the supply port (30) within the piston (44), wherein the further non-return valve (32) can be inwardly opened by a hydraulic pressure prevailing at the supply port (30) .
13. Pivoting motor adjuster (14) of a camshaft (18), comprising a hydraulic valve (12) according to one of the preceding claims, wherein a first work port (34) is connected to a first pressure chamber (9) of the pivoting motor adjuster (14), and a second work port (36) is connected to a second pressure chamber (10) of the pivoting motor adjuster (14),
    wherein the first work port (34) and the second work port (36) can be connected in an alternating manner to one another and/or to the supply port (30) and/or to the at least one tank outlet (38, 40) by means of a displacement of the piston (44) via at least one non-return valve (46, 48),
    wherein the at least one non-return valve (46, 48) is arranged in an inner region (64) of the piston (44), which non-return valve (46, 48) comprises a strip-like flexible element (80) and, in an opened position, releases a connection between an outer side (66) of the piston (44) and the inner region (64) thereof, wherein an inner side (65) of the piston (44) has an outer stop for the non-return valve (46, 48), with the result that the element (80) can be inwardly opened by a hydraulic pressure prevailing on an outer side (66) of the piston (44), in particular a pulse-like hydraulic pressure.

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