EP2910745B1 - Hydraulic valve for a pivoting engine adjuster of a camshaft - Google Patents

Description

The invention relates to a hydraulic valve for a Schwenkmotorversteller a camshaft according to the preamble of patent claim 1.

Hydraulic valves for Schwenkmotorenversteller a camshaft are well known. The hydraulic valves have a valve piston, which is axially movable in a valve housing of the hydraulic valve. Usually, a first working connection, a second working connection and a supply connection are formed on the valve housing. The first working connection and the second working connection are connected to the swivel motor adjuster and via these connections a hydraulic fluid can be conveyed both into the hydraulic valve and out of the hydraulic valve. To supply the hydraulic valve with the aid of a conveyor conveyed hydraulic fluid, the valve housing on the supply port. The hydraulic fluid can flow through the hydraulic valve differently with the aid of a flow-through channel system of the valve piston. To use camshaft alternating torques, the hydraulic valve has at least one non-return valve in the area of the working ports. Furthermore, a check valve is formed in a flow region of the supply connection. Thus, with the help of the check valves, the hydraulic fluid in the hydraulic valve can be controlled pressure-dependent.

Check valves for hydraulic valves whose closing elements are formed band-shaped, are also known. So goes from the French patent FR 525 481 , which was already published in 1921, a check valve forth, which has a band-shaped closing element.

The patent DE 101 43 433 B4 discloses a band-shaped closing element of a hydraulic valve, wherein the closing element has resiliently mounted closing flaps.

A band-shaped closing element of a check valve for a hydraulic valve can also the patent EP 2 503 201 B1 be removed. The disclosed closure valve is characterized in that it has a stop at a strap end to limit its extension. Since the closing element can only be flowed through to a limited extent due to the stop, flow openings are provided in different ways.

The published patent US 2013 206 088 A1 is a hydraulic valve refer to the non-return valve equipped with a spring-based closing element and is accommodated in the valve piston.

Likewise, check valves with a band-shaped closing element for Schwenkmotorenversteller for camshafts are known. The publications DE 10 2010 061 337 A1 and DE 10 2010 019 004 A1 disclose hydraulic valves with a band-shaped closing element of the check valve. In contrast to that from the DE 10 2010 061 337 A1 known hydraulic valve, which in each case uses a check valve for the first working port and the second working port, has in the DE 10 2010 019 004 A1 disclosed hydraulic valve on a single check valve, by means of which the first working port and the second working port can be acted upon depending on the positioning along a longitudinal axis of the valve housing axially displaceable valve piston in the valve housing of the hydraulic valve. The working port and the second working port are axially spaced from each other, wherein the supply port of the valve housing between the first working port and the second working port is arranged. For the flow through the hydraulic valve, the connections are assigned ring grooves in the valve housing.

The check valve is on the valve housing movable in the valve piston in a ring grooves facing formed positioning of the valve piston, which connected to the channel system is flowed through, arranged. Due to the axial displaceability of the valve piston, it is possible to use the first check valve for both working connections.

The hydraulic fluid can flow through the hydraulic valve differently with the aid of the flow-through channel system, wherein a first tank connection of the hydraulic valve for draining the hydraulic fluid out of the hydraulic valve is formed on the valve housing.

For quick adjustment of the camshaft is a quick and unimpeded response of the hydraulic valve, in other words a rapid axial displacement of the valve piston in the valve housing required. For this purpose, it is necessary that the closing element of the check valve does not strike the valve housing during operation of the Schwenkmotorverstellers.

The object of the present invention is to provide a hydraulic valve for a Schwenkmotorversteller a camshaft, which has an improved response.

The object is achieved by a hydraulic valve for a Schwenkmotorversteller a camshaft with the features of claim 1. Advantageous embodiments with expedient and non-trivial developments of the invention are specified in the respective subclaims.

The erfindungemäße hydraulic valve for a Schwenkmotorversteller a camshaft has a non-return valve at least partially comprehensive limiting element for limiting a radial extent of the check valve. Due to the at least partially enclosing the check valve, in particular a closing element of the check valve, the check valve in its radial extent, which in the operation of the Hydraulic valve has limited. This leads to an improved, because faster response of the hydraulic valve, since a stop or a touch of the check valve is prevented on the valve housing.

Depending on a pressure ratio formed on the check valve, the check valve opens. Since the closing element of the check valve is strip-shaped, the positioning groove is designed to be comprehensive over its circumference, it expands as a function of the pressure ratio in the radial direction. In other words, that means that the closing element at least partially expands in the direction of the valve housing. According to the applied pressure ratio, this radial expansion is pronounced. A large pressure ratio leads to a strong expansion, that is to say that the closing element can extend at least partially radially out of the positioning groove in such a way that the closing element can rest on a valve inner surface facing the positioning groove, or can touch it. This contact may result in damage to the valve housing and / or obstruction of the axial movement of the valve piston.

The limiting element prevents a corresponding contact of the non-return element with the valve housing, since it is formed at least partially encompassing the non-return element, thus representing an obstacle of the non-return element in its radial extent.

For effective limitation of the non-return element, the limiting element is designed to be supported on the valve piston. As a result, both the radial arrangement and the axial arrangement of the limiting element relative to the non-return element in each position of the valve piston is maintained, so that a prevention of contact or abutment of the non-return element or its closing element is secured to the valve housing. If the limiting element, for example, provided on the valve housing, which would lead to a change in the axial arrangement relative to the non-return element at an axial Displacement of the valve piston lead, and the non-return element could strike in an area not covered by the limiting element on the valve housing.

The limiting element, like the non-return valve, is arranged in the positioning groove of the valve piston. To ensure a radial distance between the closing element of the check valve and the limiting element, which is necessary so that the check valve can open within this radial distance, the limiting element is added to a first shoulder and a second shoulder of the positioning, which in the necessary radial distance are formed to the closing element of the check valve on walls of the positioning groove.

So that the hydraulic fluid can flow in the direction released by the check valve, the limiting element has at least one passage opening. Ideally, passage openings are arranged distributed over a circumference of the limiting element. These passage openings are to be designed such that a flow resistance, which necessarily exists through the limiting element in the flow path of the hydraulic fluid, is as small as possible. This means that an effective flow cross section of the limiting element, which results from the sum of the individual effective flow cross sections of the passage openings, should at least approximately correspond to the effective flow cross section of the positioning groove. This is necessary so that pressure losses or flow losses, which can be brought about by the limiting element, are avoided as far as possible.

For easy installation of the limiting element, the limiting element is made of a band. The band is bent the paragraphs in the positioning, thus under a slight bias, introduced, wherein for producing a hollow cylindrical shape of the limiting element a first band region of the band and a second band region of the band in the installed state are arranged overlapping.

Advantageously, a second tank port of the hydraulic valve is formed on the valve housing, so that the first working port and the second working port per a tank port is independently assignable.

In a further embodiment of the hydraulic valve according to the invention, the valve piston has a throttle element for throttling a fluid drain of the hydraulic fluid on the valve piston, in particular comprising this over its radial circumference. Usually, throttle elements are arranged on the valve housing in areas of end faces of the valve piston. This arrangement leads to an axial force acting on the correspondingly acted on end face of the valve piston. If the throttle element is designed as proposed on the valve piston, in particular on its circumference, formation of the axial force is eliminated, so that a change in position of the valve piston in the hydraulic valve can be brought about quickly since the valve head does not have to be displaced against an axial force produced by the throttle element.

In a cost-effective variant, the throttle element has a polygonal-shaped circumference. This polygonal circumference can be realized in a simple way, for example, by so-called percussion turning.

The hydraulic valve is advantageously designed as a central valve, so that compared to an external hydraulic valve on the one hand, a space advantage and on the other hand, an improved response is realized, since conduction paths of the hydraulic fluid can be kept short.

Fig. 1

in einem Querschnitt einen Schwenkmotorversteller,

Fig. 2

in einem Längsschnitt ein erfindungsgemäßes Hydraulikventil,

Fig. 3

in einem Ausschnitt ein Längsschnitt des Hydraulikventils gem. Fig. 2,

Fig. 4

in einem Längsschnitt eine 3-dimensionale Darstellung eines Ventilkolbens des Hydraulikventils gem. Fig. 2,

Fig. 5

in einer perspektivischen Darstellung einen Käfig des Hydraulikventils gem. Fig. 2, und

Fig. 6

in einer perspektivischen Darstellung den Ventilkolben gem. Fig. 4.

Further advantages, features and details of the invention will become apparent from the following description of preferred embodiments and from the Drawing. The features and feature combinations mentioned above in the description as well as the features and feature combinations mentioned below in the description of the figures and / or shown alone in the figures can be used not only in the respectively indicated combination but also in other combinations or in isolation, without the scope of To leave invention. Identical or functionally identical elements are assigned identical reference numerals. For reasons of clarity, it is possible that the elements are not provided with reference numbers in all figures, but without losing their assignment. Show it:

Fig. 1

in a cross section a Schwenkmotorversteller,

Fig. 2

in a longitudinal section of an inventive hydraulic valve,

Fig. 3

in a section a longitudinal section of the hydraulic valve acc. Fig. 2 .

Fig. 4

in a longitudinal section a 3-dimensional representation of a valve piston of the hydraulic valve acc. Fig. 2 .

Fig. 5

in a perspective view of a cage of the hydraulic valve acc. Fig. 2 , and

Fig. 6

in a perspective view of the valve piston acc. Fig. 4 ,

A Schwenkmotorversteller 1 according to Fig. 1 allows during operation of an internal combustion engine, not shown, to bring about a change of opening and closing times of gas exchange valves of the internal combustion engine. For this purpose, with the aid of the Schwenkmotorverstellers 1, a relative angular position of a camshaft, not shown, of the internal combustion engine with respect to a not shown crankshaft of the internal combustion engine continuously changed, wherein the camshaft is rotated relative to the crankshaft. By turning the camshaft, the opening and closing times of the gas exchange valves are shifted so that the internal combustion engine brings its optimum performance at the respective speed.

The Schwenkmotorversteller 1 has a cylindrical stator 2 which is rotatably connected to a drive wheel 3 of the camshaft. In the exemplary embodiment, the drive wheel 3 is a sprocket over which a chain, not shown, is guided as a drive element. The drive wheel 3 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 3, the stator 2 is drivingly connected to the crankshaft.

The stator 2 has a cylindrical stator base 4, on which on the inside 5 radially inwardly extending webs 6 are formed at regular intervals, such that between each two adjacent webs 6, a gap 7 is formed. In this space 7 is a pressure medium, generally a hydraulic fluid, with the aid of an in Fig. 2 introduced hydraulic valve 20 shown in a controlled manner.

In the intermediate space 7 protruding a wing 8 is positioned, which is arranged on a rotor hub 9 of a rotor 10. The number of gaps 7 corresponding to the rotor hub 9 a number of wings 8.

With the help of the wings 8 thus the interstices 7 are each divided into a first pressure chamber 11 and a second pressure chamber 12. To reduce a pressure loss in the first pressure chamber 11 and the second pressure chamber 12, the webs 6 are formed with their first end faces 13 sealingly against an outer circumferential surface 14 of the rotor hub 9. Likewise, the wings are 8 with their second end faces 15 sealingly on one of Outer shell surface 14 oppositely positioned inner wall 16 of the stator base 4 at.

The rotor 10 is rotatably connected to the camshaft of the internal combustion engine. In order to change the angular position between the camshaft and the crankshaft, the rotor 10 is rotated relative to the stator 2. For this purpose, depending on the selected direction of rotation, the pressure medium in the first pressure chamber 11 or in the second pressure chamber 12 is pressurized, while the second pressure chamber 12 and the first pressure chamber 11 is relieved. The discharge takes place with the help of a tank access, which is open for relief. It may be a single accessible for the first pressure chamber 11 and the second pressure chamber 12 tank access, or as in the embodiment according to. Fig. 2 1, a first tank access T1 and the second pressure chamber 12 a second tank access T2 is associated with the first pressure chamber 11.

Thus, the rotor 10 is rotated relative to the stator 2 in the clockwise direction, 20 radial first hub bores 17 are pressurized by means of the hydraulic valve, which are arranged distributed regularly over the circumference of the rotor hub 9. To rotate the rotor 10 relative to the stator 2 in the counterclockwise direction by means of the hydraulic valve 20 radial second hub bores 18 are pressurized, which are also distributed over the circumference of the rotor hub 9, said second hub bores 18 axially spaced from the first hub bores 17 are positioned.

In Fig. 2 the hydraulic valve 20 according to the invention is shown in a longitudinal section in a first valve position. The hydraulic valve 20 is constructed similar to a cartridge valve and has a valve housing 21, within which a valve piston 22 is arranged axially displaceable.

To displace the valve piston 22, a first end face 23 of the valve piston 22, which faces away from the internal combustion engine, is closed, so that a plunger 24 of an electromagnetic linear actuator 25 can abut against this first end face 23. An energization of the linear actuator 25 leads to the axial displacement of the valve piston 22 in the direction of the internal combustion engine, wherein a at a second end face 26 of the valve piston 22, which is remote from the first end face 23, attached retaining member 27 exerts a retaining force on the valve piston 22, against which is the valve piston 22 to move. The retaining element 27, in the form of a helical compression spring in this embodiment, is supported on a hollow cylinder 28, which is arranged in the region of a housing end face 29 facing the internal combustion engine with an interference fit in the valve housing 21.

The bush-like valve housing 21 has a supply connection P, a first working connection A and a second working connection B. The supply port P, the first working port A and the second working port B are associated with a first annular groove 30, a second annular groove 31 and a third annular groove 32, which are each connected via connection channels not shown with the terminals. The connection channels are formed a housing wall 34 of the valve housing 21 completely penetrating.

The supply port P is designed for connection to an oil pump, not shown, so that the hydraulic valve 20 with the hydraulic fluid, which is oil in this embodiment, can be supplied. The first working port A is connected to the first hub bores 17, the second working port B is connectable to the second hub bores 18. The first tank access T1 is arranged on the housing end face 29. The second tank access T2 is connected to an axially spaced from the supply port B fourth annular groove 33 of the valve housing 21 by means of another in the fourth Annular groove 33 opening not shown connection channel connectable. The fourth annular groove 33 is arranged between the first end face 23 and the third annular groove 32.

The valve piston 22 is designed to flow through and has a channel system 35, which can be flowed through by the hydraulic fluid. Along a longitudinal axis 36 of the valve piston 22 is a supply channel 37 of the channel system 35, which a first channel group 38, a second channel group 39 and a third channel group 40, each axially spaced from each other, traverse. The first channel group 38, the second channel group 39 and the third channel group 40 are fluidly connected to one another with the aid of the supply channel 37, so that hydraulic fluid from, for example, the first channel group 38 flows via the supply channel 37 into the second channel group 39 and / or third channel group 40 can. A channel group is composed in this embodiment of two intersecting and perpendicular to each other positioned transverse bores, which are formed over a diameter D of the valve piston 22, this completely penetrating, extending. Similarly, the channel group could also have a different number of transverse holes.

At the ends of the first channel group 38, the second channel group 39 and the third channel group 40 facing a lateral surface 41 of the valve piston 22, the valve piston 22 has an annular groove, ie a positioning groove 42, a fifth annular groove 42a and a sixth annular groove 42b , wherein the ends of the first channel group 38 in the positioning groove 42, the ends of the second channel group 39 in the fifth annular groove 42 a and the ends of the third channel group 40 in the sixth annular groove 42 b open. In the positioning groove 42, a first check valve 43 is received, the closing element is formed band-shaped. A check valve with a band-shaped closing element is known and can, for example. The EP 1 703 184 B1 or removed. At this point it should be pointed out that per Definitionem a check valve basically consists of a housing and a flow opening of the housing opening or closing closing element. In the case of a band-shaped closing element, the flow-restricting walls can be used to form the housing of the check valve for the band-shaped closing element, as the illustrated embodiment shows. Therefore, below the first check valve 43 is to be understood the formed closing element and vice versa.

The first check valve 43 prevents inflow of the hydraulic fluid from the first annular groove 30, from the second annular groove 31 and from the third annular groove 32 in the first channel group 38. In contrast, the first check valve 43 opens if hydraulic fluid flows through the first channel group 38 from the supply channel 37 , In other words, the first check valve 43 closes in the direction of the supply channel 37 and opens in the direction of the annular grooves 30, 31, 32.

A second check valve 4 is provided outside the valve housing 21 between the supply port P and the oil pump for preventing backflow of the hydraulic fluid into the oil pump.

The in the Fig. 2 In this state, the fifth annular groove 42 a at least partially covers the second annular groove 31, so that the hydraulic fluid from the first pressure chambers 11 via the first hub bores 17, the first working port A and the second annular groove 31 can flow into the fifth annular groove 42 a and further into the second channel group 39, provided that a first pressure in the first pressure chambers 11 exceeds a second pressure present in the channel system 35. The hydraulic fluid flowing out of the second annular groove 31 is divided into a first fluid flow and a second fluid flow in the attempt to equalize the pressure.

The first fluid flow can flow out of the second annular groove 31 due to the partial overlap with the fifth annular groove 42a and the second annular groove 31 via a first gap 44a in the first tank access T1 according to the direction of the arrow PR1, s. Fig. 3 wherein the first gap 44a is formed in the region between the second end face 26 and the fifth annular groove 42a between the lateral surface 41 and a valve inner surface 49 of the valve housing 21. The gap 44 a is formed in sections over the circumference of the valve piston 22.

The second fluid stream flows according to the second arrow direction PR2 into the second channel group 39 and from there into the supply channel 37, wherein it passes into the third annular groove 32 via the first check valve 43. The third annular groove 32 is at least partially covered by the positioning groove 42 in this first valve position, so that the inflow of the hydraulic fluid from the first channel group 38 can take place via the positioning groove 42 into the third annular groove 32. The hydraulic fluid flowing from the supply port P to the first check element 43 flows into the third annular groove 32 via a third gap 44e which is formed in this first valve position between the positioning groove 42 and the valve inner surface 49 in accordance with the third arrow direction PR3.

The hydraulic fluid thus passes through the second working port B in the second hub bores 18 which communicate with the second pressure chambers 12, so that the pressure in the second pressure chambers 12 increases and the drive wheel 3 is rotated relative to the stator 2 counterclockwise.

As soon as the camshaft endeavors to rotate in the direction to be adjusted as a result of its alternating torques, the pressure in the first pressure chambers 11 increases. When this pressure is so great that the preloaded first check valve 43 opens, the second working port B becomes the second pressure chambers 12, which have a suction effect due to a negative pressure, provided sufficient hydraulic fluid, so that a Rotation of the rotor 10 takes place. There is a rapid rotation, as it would not be possible alone with the oil pump.

A second valve position is to be adjusted by means of an energization of the linear actuator 25. The valve piston 22 is pushed against the force of the retaining element 27 in the direction of the first tank access T1 in its end position. In this end position, the second end face 26 bears against the hollow cylinder 28. In this case, the valve piston 22 has been moved axially so far that the overlap of the fifth annular groove 42a and the second annular groove 31 has been canceled, so that the second annular groove 31 is closed by means of the lateral surface 41.

Due to the axial displacement of the valve piston 22, an overlap of the positioning groove 42 and the second annular groove 31 and the first annular groove 30, so that an overflow of the hydraulic fluid from the supply port P takes place in the first working port A. Furthermore, an at least partial overlap of the sixth annular groove 42b and the third annular groove 32 is produced. The hydraulic fluid, which now flows from the second working port B, is divided into a third fluid flow and a fourth fluid flow, wherein the third fluid flow via the third channel group 40 and the supply channel 37 can enter the first channel group 38.

After opening the first check valve 43, the third fluid flow continues to flow from the positioning groove 42 into the second annular groove 31. The fourth fluid flow flows via a second gap 44b formed between the valve inner surface 49 and the lateral surface 41 into the second tank port T2.

This relationship and the basic principle of the hydraulic valve 20 are also closer in the DE 10 2010 019 004 A1 explained, so that will not be discussed further here.

In the Fig. 4 the valve piston 22 is shown 3-dimensionally in a longitudinal section along the longitudinal axis 36. The positioning groove 42 is designed step-shaped, such that in its radial extent on its first end face 26 facing formed first wall 50, a first shoulder 51 and at its first wall 50 oppositely positioned second wall 52, a second shoulder 53 is formed, so that the positioning groove 42 has a first axial extent E1 and a second axial extent E2, the first axial extent E1 being smaller than the second axial extent E2.

The first check valve 43 is received in the region of the positioning groove 42, which has the first extension E1, wherein the first wall 50 and the second wall 52 of an axial securing of the first check valve 43 are used. Axial end portions of the band-shaped closing element of the check valve 43 are slightly overlapping each other, so that an opening pressure can be kept low.

To limit a radial extent of the check valve 43 and the closing element of the check valve 43, an annular limiting element 45, the check valve 43 comprising the valve piston 22 is arranged. The limiting element 45 is in Fig. 5 , a perspective view, shown in more detail. The limiting element 45 is made of a band 45d which has transverse struts 45c of the band 45d arranged between a first longitudinal strut 45a of the band 45d and a second longitudinal strut 45b of the band 45d, wherein the transverse struts 45c connect the first longitudinal strut 45a and the second longitudinal strut 45b to one another are formed.

For positioning the limiting element 45 on the valve piston 22 and thus for embracing the first check valve 43, the band-shaped limiting element 45 is bent so far that a first Bandendbereich 46 and a second Bandendbereich 47 overlap each other and the band 45d rests in the form of a ring on the valve piston 22.

Between the transverse struts 45c and the longitudinal struts 45a, 45b passage openings 48 of the limiting element 45 for free passage of the hydraulic fluid in this embodiment are rectangular.

For example, the limiting element 45 could also be produced from a band-shaped perforated plate, so that the limiting element 45 provided with numerous passage openings 48 is constructed similarly to a sieve. There are further modifications of the limiting element 45 are conceivable, wherein the passage openings 48 are to be designed so that a pressure loss, which may arise by the limiting element 45 in the flow path of the hydraulic fluid from the first channel group 38 in the positioning groove 42, is minimized or eliminated ,

The limiting element 45 is arranged supportingly on the valve piston 22 on the first shoulder 51 and on the second shoulder 52 with the aid of the first longitudinal strut 45a and the second longitudinal strut 45b. In other words, the first longitudinal strut 45a and the second longitudinal strut 45b lie at least partially in their axial extent on the first shoulder 51 and the second shoulder 52, wherein the passage openings 48 form a free flow cross-section for the hydraulic fluid. A radial extent of the first check valve 43 is limited by means of the transverse struts 45c, so that a contact of the first check valve 43 and the closing element of the check valve 43 with the valve inner surface 49 is prevented.

A realization of an axial force-free throttling of the flow of hydraulic fluid in the first tank access T1 and in the second tank access T2 by means of a first throttle element 54 and a second throttle element 55th The first throttle element 54 is between the fifth annular groove 42a and the second end face 26 at the fifth annular groove 42a adjacent and the second throttle element 55 is between the sixth annular groove 42b and the first end surface 23 adjacent to the sixth annular groove 42b. These throttle elements 54, 55 completely surround the radial circumference of the valve piston 22.

The first throttle element 54 and the second throttle element 55 have a polygonal-shaped radial circumference, s. especially Fig. 6 such that the first gap 44a and a first sealing surface 44c or the second gap 44b and a second sealing surface 44d are configured alternately over the radial circumference of the valve inner surface 49 with the aid of the first throttle element 54 or with the aid of the second throttle element 55.

The first throttle element 54 extends adjacent to the fifth annular groove 42a over an axial first length L1 and the second throttle element 22b extends adjacent to the sixth annular groove 42b over an axial second length L2. In this embodiment, the first length L1 corresponds to the second length L2. Likewise, the first length L1 could be different from the second length L2. The first length L1 and the second length L2 correspond to a desired throttle effect.

The polygonal-shaped radial circumference has the shape of a pentagon. Likewise, it could also have the shape of another polygon, wherein due to the reduction of the pressure loss, the polygonal radial circumference of the first throttle element 54 and the second throttle element 55 should have not less than five polygon edges. Likewise, the number of polygonal edges should not exceed a certain number depending on the diameter D of the valve piston 22. This would mean too little differentiation between the circular radial circumference of the valve piston 22, so that a drainage of the hydraulic fluid via the first tank port T1 and the second tank port T2 would be too much throttled.

As in particular in the Figures 2 and 3 is shown, with the aid of the polygonal of the first throttle element 54, the first gap 44 a brought about. This first gap 44a does not extend completely over the radial circumference of the valve piston 22, but the first throttle element 54 is partially adjacent to the valve inner surface 49. Thus, the first gap 44a is formed only in sections.

In the region of the sixth annular groove 42b, a second gap 44b is realized with the aid of the polygonal radial circumference of the second throttle element 55, so that the hydraulic fluid from the third channel group 40 can flow throttled into the second tank port T2 via the second gap 44b.

LIST OF REFERENCE NUMBERS

1

Schwenkmotorversteller

2

stator

3

drive wheel

4

stator base

5

inside

6

web

7

gap

8th

wing

9

rotor hub

10

rotor

11

first pressure chamber

12

second pressure chamber

13

first faces

14

Outer casing surface

15

second end faces

16

inner wall

17

first hub bores

18

second hub bores

20

hydraulic valve

21

valve housing

22

plunger

23

first end face

24

tappet

25

Linear Actuator

26

second end face

27

Retaining element

28

hollow cylinder

29

Housing face

30

first ring groove

31

second annular groove

32

third annular groove

33

fourth ring groove

34

housing wall

35

channel system

36

longitudinal axis

37

supply channel

38

first channel group

39

second channel group

40

third channel group

41

lateral surface

42

positioning groove

42a

fifth ring groove

42b

sixth ring groove

43

first check valve

44a

first gap

44b

second gap

44c

first sealing surface

44d

second sealing surface

44e

third gap

45

limiting element

45a

first longitudinal strut

45b

second longitudinal strut

45c

crossmember

45d

tape

46

first band area

47

second band area

48

Port

49

Valve inside surface

50

first wall

51

first paragraph

52

second wall

53

second paragraph

54

first throttle element

55

second throttle element

A

first work connection

B

second work connection

D

diameter

DI

Inner diameter

E1

first axial extent

E2

second axial extent

L1

first length

L2

second length

P

supply terminal

PR1

first arrow direction

PR2

second direction of the arrow

PR3

third arrow direction

T1

first tank access

T2

second tank access

Claims (11)

1. Hydraulic valve for a pivoting motor adjuster of a camshaft, having a valve housing (21) with a longitudinal axis (36) and a valve piston (22) which can be positioned in the valve housing (21) such that it can be displaced axially along the longitudinal axis (36), it being possible for a first working connector (A) of the valve housing (21) and a second working connector (B) of the valve housing (21) to be opened and closed with the aid of the valve piston (22), the first working connector (A) and the second working connector (B) being spaced apart from one another axially, and having a supply connector (P) of the valve housing (21) which serves to supply the hydraulic valve (21) with a hydraulic fluid which is delivered with the aid of a delivery device, it being possible for the hydraulic fluid to flow through the hydraulic valve (20) in different ways with the aid of a duct system (35) of the valve piston (22), through which duct system (35) flow can pass, and a first tank connector (T1) of the hydraulic valve (20) being configured on the valve housing (21) for discharging the hydraulic fluid from the hydraulic valve (20), and a first check valve (43) being positioned on the valve piston (22) in a positioning groove (42) of the valve piston (22) in order to avoid a discharge of hydraulic fluid from the positioning groove (42) into the duct system (35), characterized in that the hydraulic valve (20) has a limiting element (45) which encloses the first check valve (43) at least partially in order to limit a radial extent of the first check valve (43).
2. Hydraulic valve according to Claim 1, characterized in that the limiting element (45) is configured such that it is supported on the valve piston (22).
3. Hydraulic valve according to Claim 1 or 2, characterized in that the valve piston (22) has a shoulder (51; 53) for positioning the limiting element (45).
4. Hydraulic valve according to one of the preceding claims, characterized in that the limiting element (45) is of hollow-cylindrical configuration and has at least one passage opening (48) distributed over its circumference.
5. Hydraulic valve according to one of the preceding claims, characterized in that the limiting element (45) is configured in the form of a curved strip (45d).
6. Hydraulic valve according to one of the preceding claims, characterized in that a first strip region (46) of the strip (45d) and a second strip region (47) of the limiting element (45) are arranged so as to overlap in the installed state.
7. Hydraulic valve according to one of the preceding claims, characterized in that a second tank connector (T2) of the hydraulic valve (20) is configured on the valve housing (21).
8. Hydraulic valve according to one of the preceding claims, characterized in that the valve piston (22) has a throttle element (54; 55) for throttling a fluid discharge of the hydraulic fluid.
9. Hydraulic valve according to Claim 8, characterized in that the throttle element (54; 55) provides a gap (44a, 44b) for the fluid discharge of the hydraulic fluid in sections, which gap (44a, 44b) is configured between a valve inner face (49) of the valve housing (21) and a circumferential face (41) of the valve piston (22).
10. Hydraulic valve according to either of Claims 8 and 9, characterized in that the throttle element (54; 55) has a radial circumference of polygonal configuration.
11. Hydraulic valve according to one of the preceding claims, characterized in that the hydraulic valve (20) is configured as a central valve of the pivoting motor adjuster (1).

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