EP1924759A1

EP1924759A1 - Control valve for a device for changing the control times of an internal combustion engine

Info

Publication number: EP1924759A1
Application number: EP06762977A
Authority: EP
Inventors: Gerhard Scheidig; Ali Bayrakdar; Jens Hoppe; Rainer Ottersbach
Original assignee: Schaeffler KG
Current assignee: Schaeffler Technologies AG and Co KG
Priority date: 2005-09-01
Filing date: 2006-08-04
Publication date: 2008-05-28
Anticipated expiration: 2026-08-04
Also published as: CN101253312B; DE102005041393A1; EP1924759B1; KR101292391B1; CN101253312A; DE502006008954D1; US20080236529A1; US7849825B2; WO2007025630A1; KR20080040746A

Abstract

The invention relates to a control valve (20) for a device (1) for variably setting the control times of gas exchange valves (110, 111) of an internal combustion engine (100). Two working ports (A, B) and one supply port (24) are formed on an outer casing surface of a valve housing (22) of the control valve (20), the working ports (A, B) being arranged directly adjacent, and the supply port (24) adjoins them. Furthermore, there is provision for two pressure medium ducts (40, 41) to be formed on the control piston (30), at least one of the pressure medium ducts (40, 41) being embodied so that it is not rotationally symmetrical with respect to the longitudinal axis (36) of the control piston (30).

Description

Name of the invention

Control valve for a device for changing the timing of an internal combustion engine

description

Field of the invention

The invention relates to a control valve for a device for changing the timing of an internal combustion engine according to the preamble of claims 1 or 2 and a device for changing the timing of an internal combustion engine according to the preamble of claim 18th

In internal combustion engines, camshafts are used to actuate the gas exchange valves. Camshafts are mounted in the internal combustion engine such that cams attached to them abut cam followers, for example cup tappets, drag levers or rocker arms. If a camshaft is rotated, the cams roll on the cam followers, which in turn actuate the gas exchange valves. Due to the position and the shape of the cams thus both the opening duration and the opening amplitude but also the opening and closing times of the gas exchange valves are set.

Modern engine concepts go to design the valve train variable. On the one hand, valve lift and valve opening duration should be variable, up to the complete shutdown of individual cylinders. For this purpose, concepts such as switchable cam followers or electro-hydraulic or electric valve actuators are provided. Furthermore, it has been found to be advantageous to be able to influence the opening and closing times of the gas exchange valves during operation of the internal combustion engine. It is particularly desirable for the opening and closing times of the intake or to be able to exert an influence separately on exhaust valves, for example, to set a defined valve overlap in a targeted manner. By adjusting the opening and closing times of the gas exchange valves as a function of the current map range of the engine, for example, the current speed or the current load, the specific fuel consumption can be reduced, the exhaust behavior positively influenced, increases the motor efficiency, the maximum torque and the maximum power become.

The described variability of the gas exchange valve timing is achieved by a relative change in the phase angle of the camshaft to the crankshaft. The camshaft is usually via a chain, belt, gear drive or equivalent drive concepts in drive connection with the crankshaft. Between the driven by the crankshaft chain, belt or gear drive and the camshaft, a device for changing the control times of an internal combustion engine, hereinafter also called camshaft adjuster, mounted, which transmits the torque from the crankshaft to the camshaft. In this case, this device is designed such that during operation of the internal combustion engine, the phase angle between the crankshaft and camshaft securely held and, if desired, the camshaft can be rotated in a certain angular range relative to the crankshaft.

In internal combustion engines, each with a camshaft for the intake and the exhaust valves, these can each be equipped with a camshaft adjuster. As a result, the opening and closing times of the inlet and outlet gas exchange valves can be shifted relative to one another in terms of time and the valve overlaps can be adjusted in a targeted manner.

The seat of modern camshaft adjusters is usually located on the drive end of the camshaft. The camshaft adjuster can also be arranged on an intermediate shaft, a non-rotating component or the crankshaft. It consists of a driven by the crankshaft, a fixed phase relation to this holding drive wheel, one in Antriebsver- Binding with the camshaft stationary driven part and the torque transmitted from the drive wheel to the driven part adjusting mechanism. In the case of a camshaft adjuster not arranged on the crankshaft, the drive wheel can be designed as a chain, belt or gearwheel and is driven by the crankshaft by means of a chain, a belt or a gearwheel drive. The adjustment mechanism can be operated electrically, hydraulically or pneumatically.

Two preferred embodiments of hydraulically adjustable camshaft adjusters are the so-called axial piston adjuster and rotary piston adjuster.

In the Axialkolbenverstellern the drive wheel is connected to a piston and this with the output part via helical gears in combination. The piston separates a cavity formed by the driven part and the drive wheel into two pressure chambers arranged axially relative to one another. If one pressure chamber is acted upon by pressure medium while the other pressure chamber is connected to a tank, then the piston shifts in the axial direction. The axial displacement of the piston is translated by the helical gears in a relative rotation of the drive wheel to the output part and thus the camshaft to the crankshaft.

A second embodiment of hydraulic phaser are the so-called Rotationskolbenversteller. In these, the drive wheel is rotatably connected to a stator. The stator and a rotor or driven element are arranged concentrically to one another, wherein the rotor is non-positively, positively or materially connected, for example by means of a press fit, a screw or welded connection with a camshaft, an extension of the camshaft or an intermediate shaft. In the stator, a plurality of circumferentially spaced cavities are formed which extend radially outward from the rotor. The cavities are limited pressure-tight in the axial direction by side cover. In each of these cavities, a wing connected to the rotor extends, each cavity in two pressure chambers Splits. By selectively connecting the individual pressure chambers with a pressure medium pump or with a tank, the phase of the camshaft can be adjusted or held relative to the crankshaft.

To control the camshaft adjuster sensors detect the characteristics of the engine such as the load condition and the speed. These data are fed to an electronic control unit which, after comparing the data with a characteristic data field of the internal combustion engine, controls the inflow and outflow of pressure medium to the various pressure chambers.

In order to adjust the phase position of the camshaft relative to the crankshaft, one of the two counteracting pressure chambers of one cavity is connected in hydraulic camshaft adjusters with a pressure medium pump and the other with the tank. The inlet of pressure medium to a chamber in conjunction with the flow of pressure medium from the other chamber moves the pressure chambers separating piston in the axial direction, whereby in Axialkolbenverstellern on the helical gears, the camshaft is rotated relative to the crankshaft. In Rotationskolbenverstellern is caused by the pressurization of a chamber and the pressure relief of the other chamber, a displacement of the wing and thus directly a rotation of the camshaft to the crankshaft. To keep the phase position both pressure chambers are either connected to the pressure medium pump or separated from both the pressure medium pump and the tank.

The control of the pressure medium flows to and from the pressure chambers by means of control valves, usually by means of a 4/3-way proportional valve. This has a valve housing, which is each provided with a connection for the pressure chambers (working port) and at least two supply connections. At least one of the supply connections serves as inlet connection, via which the control valve pressure medium is supplied from a pressure medium pump. Furthermore, a further supply connection serves as an outlet connection, via which the pressure medium leaving the pressure chambers is removed. leads. It can be provided, for example, that the drain connection communicates with a tank.

Within the substantially hollow cylindrical valve housing an axially displaceable control piston is arranged. The control piston can be brought axially into any position between two defined end positions by means of an electromagnetic, pneumatic or hydraulic actuator, against the spring force of a spring element. The control piston is further provided with control edges, whereby the working ports with the supply ports and thus the individual pressure chambers or groups of pressure chambers can be selectively connected to the pressure medium pump or the tank. Likewise, a position of the control piston may be provided, in which the pressure medium chambers are separated from both the pressure medium pump and the pressure medium tank.

Such a control valve is known from US 6,363,896 B1. This consists of a substantially hollow cylindrical valve housing and an axially displaceably arranged therein control piston. Two working connections, an inlet connection and a drain connection are formed on the valve housing. The two working ports and the inlet port are formed as axially spaced openings in the cylindrical surface of the valve housing. The inlet connection lies in the axial direction between the two working connections. Furthermore, an axial outlet connection is provided, via which pressure medium can be removed from the control valve.

Within the valve housing, a control piston is provided, which can be moved by means of an electromagnetic actuator in the axial direction relative to the valve housing. On the outer circumferential surface of the control piston, an annular groove is formed, via which, depending on the position of the control piston to the valve housing, either the first or the second working port can be selectively connected to the inlet port. Depending on the relative position of the control piston within the valve housing, the drain connection can either be connected directly to the one working Conclusion or be connected by means of a pressure medium channel formed within the control piston with the other working port. Furthermore, a supply line is provided, via which the inlet connection communicates with a pressure medium pump, which supplies the control valve with continuous pressure medium.

The position of the inlet connection between the working connections requires a complex pressure medium guide within the driven element. On the one hand, both radially extending pressure medium lines, starting from one of the working connections, and axially extending supply lines, starting from the radial supply connection are located within an axial section of the output element. This accumulation of lines in an axial section reduces their maximum flow cross-sections. A further disadvantage arises from the fact that a connection between the axial supply lines and the radial pressure medium lines must be prevented. For this purpose, in the prior art, the supply lines are formed by a plurality of thin bores communicating with each other, via which pressure medium is supplied from a camshaft bearing to the inlet port. The formation of these holes is very cost-intensive and error-prone. In addition, the process reliability suffers because the thin drills tend to break during the formation of the holes.

Summary of the invention

The invention is therefore based on the object to avoid these disadvantages and thus to provide a hydraulic control valve, wherein the pressure medium supply to the inlet port and the pressure fluid discharge from the tank connection by simple, inexpensive to produce constructive features can be accomplished. Another object is to realize a simple and inexpensive to produce connection between the working ports and the pressure chambers of the camshaft adjuster. In a first embodiment of a control valve for a device for variably setting the timing of gas exchange valves of an internal combustion engine having a substantially hollow cylindrical valve housing, and a control piston arranged axially displaceably, wherein on the valve housing exactly two working ports, just a first and exactly one are formed via one of the supply connections to the control valve pressure medium from a pressure medium pump and can be discharged via the other supply port pressure medium from the control valve in a tank, wherein both working ports and the first supply port through at least one radial opening in an outer circumferential surface are formed of the valve housing, wherein the working ports and the first supply port are arranged in the axial direction spaced from each other, and wherein the first supply Anschl uss communicates with a supply line, the object is achieved in that the working ports are arranged directly adjacent in the axial direction and the first supply port is connected in the axial direction on the side of the supply line to the working ports.

The control valve according to the invention consists of a substantially hollow cylindrically designed valve housing and a control piston arranged axially displaceable therein. The valve housing is arranged within a valve receptacle of a surrounding construction, for example a camshaft, a cylinder head or an output element of a camshaft adjuster, wherein the outer diameter of the valve housing is adapted to the inner diameter of the valve receptacle. On the outer lateral surface of the valve housing, at least three axially spaced connections in the form of radial openings of the valve housing are formed. The one radial connection serves as a supply connection. The remaining radial ports serve as working ports, via which pressure medium can be passed to the pressure chambers of the device or discharged from them. In this case, the supply connection as an inlet connection, via which the control valve pressure medium is supplied, or as a drain connection, via the pressure medium the control valve is discharged serve. The supply connection is arranged in the axial direction such that no working connection is arranged between it and an axial end of the control valve. Due to this arrangement of the supply connection, a strict separation in the axial direction is established between the pressure medium lines communicating with the working connections and the supply line which communicates with the supply connection. Thus, not only the pressure medium connections, but also the pressure medium lines emanating from these are separated from one another in the axial direction, whereby the complexity of the pressure medium system is reduced. The axially extending supply line no longer penetrates into the region of the radial pressure medium lines which communicate with the working ports.

Another advantage is that the axial pressure medium channels can be formed with larger cross-sectional areas. Overall, this leads to a considerable simplification of the pressure medium system and thus to a reduction in the manufacturing cost of the device.

In an advantageous development of the invention, it is provided that the supply line is formed at least in sections as an annular space between the valve housing and the surrounding structure. Alternatively, the supply line can be formed, at least in sections, as at least one groove, which opens out onto the outer jacket surface of the control piston and opens into the first supply connection.

A further simplification of the pressure medium system results from the fact that the supply line is realized by a gap between the valve housing and the valve receptacle of the surrounding construction. In this case, a valve housing comprehensive annular channel or one or more circumferentially spaced longitudinal grooves may be provided, which open into the radial supply port. In the first case of an annular channel, the inner diameter of the valve receptacle is larger than the outer diameter of the valve housing. In the case of the longitudinal grooves, these may be on an inner lateral surface of the valve seat or an outer lateral surface of the Valve housing are formed. In both cases, this can be done inexpensively or cost-neutral during the molding process. As a result, the holes described in the prior art within the rotor, the camshaft or the cylinder head are superfluous, resulting in a significant cost reduction and increasing the process reliability in the manufacture of the device. Furthermore, this solves the durability problem of drilled rotors. It is also conceivable a combination of an annular channel and at least one adjoining axially extending channel. This variant is particularly advantageous for embodiments in which the control valve is used as a central valve. In this case, the region of the valve housing in which the axially extending channel is formed can be used for centering the device on the camshaft.

Furthermore, it can be provided that at least two axially extending, mutually delimited pressure medium channels are formed on the control piston, each of the pressure medium channels in each position of the control piston communicates with one of the supply ports, each of the pressure medium channels housing by appropriate positioning of the control piston relative to the valve at least one of the working ports can be connected and wherein at least one of the pressure medium channels is not formed rotationally symmetrical with respect to the longitudinal axis of the control valve.

By forming two axially extending, mutually delimited pressure medium channels on the control piston, wherein at least one of the pressure medium channels is not formed rotationally symmetrical with respect to the longitudinal axis of the control valve, structurally simple and inexpensive producible is achieved that the two directly adjacent working ports in the axial direction selectively can be connected to the radial or the axial Versorgungsorgungsan- conclusion. In particular, a connection can be established between the radial supply connection and the working connection which is further away from the latter in the axial direction, without the supply connection simultaneously with the closer working connection communicated.

As a result, structurally complex measures, such as, for example, additional adapter components or the formation of further supply connections on the valve housing are superfluous, as a result of which the costs of the device can be further reduced.

In a further embodiment of a control valve for a device for the variable adjustment of the timing of gas exchange valves of an internal combustion engine having a substantially hollow cylindrical valve housing, and a control piston arranged axially displaceable therein, wherein on the valve housing two working ports and two supply ports are formed, each Working port is formed by at least one radial opening in an outer circumferential surface of the valve housing, wherein the working ports are spaced apart in the axial direction, wherein at least two axially extending, mutually delimited pressure fluid channels are formed on the control piston, each of the pressure fluid channels in each position of the control piston with a the supply ports communicates, each of the pressure medium channels by appropriate positioning of the control piston relative to the valve housing with at least one de R working connections can be connected, the object is achieved in that at least one of the pressure medium channels is not formed rotationally symmetrical with respect to the longitudinal axis of the control valve.

Due to the non-rotationally symmetrical design of at least one pressure medium channel with respect to the longitudinal axis of the control valve, the control piston can be used for different valve housing configurations. In this case, for example, an insert may be provided in a control valve on whose valve housing the working connections are arranged directly adjacent. Equally conceivable is an insert in a control valve between the radial working ports a supply connection is provided. Thus, one and the same component can be used for differently designed control valves, resulting in significant savings in the manufacture of the device leads.

Furthermore, the design of the external components, especially in the case of directly adjacent working connections, can be significantly simplified and thus space and costs can be saved.

In a development of the invention, it is provided that the working connections are arranged directly adjacent in the axial direction. It can be formed on the valve housing exactly two working connections and / or exactly two supply connections. Furthermore, it can be provided that one of the supply connections is designed as a feed connection, via which the control valve pressure medium is supplied and / or that one of the supply connections is designed as a drain port can be discharged via the pressure medium from the control valve to a tank.

By axially adjacent directly arranged working ports of the axial space requirement of the control valve can be reduced. Furthermore, a simpler Druckmittelzu- or discharge to the axially outer supply port is possible. The nonrotation-symmetrical design according to the invention of at least one pressure medium channel with respect to the longitudinal axis of the control valve offers the advantage of establishing the communication between the working connection farther from the radial supply connection and the supply connection without establishing a connection to the working connection therebetween. In the process, this can take place without further design features, such as adapters, and furthermore it is possible to dispense with the formation of further supply connections to the valve housing.

In both embodiments, it can be provided that at least one pressure medium channel is formed on an outer circumferential surface of the control piston.

In this embodiment of the invention, one of the pressure medium channels is formed as a second pressure medium channel extending in the axial direction of the outer piston surface of the control piston. From the axially extending groove one or two axially spaced, extending in the circumferential direction of grooves, which establish the connection between the second pressure medium channel and the circumferentially to the pressure medium channel spaced radial openings in the valve housing, which form the working connections. In the case of a circumferentially extending groove, two radial openings are provided on the control piston, through which the exterior of the control piston can communicate with its interior. In this case, the circumferentially extending groove is located on the outer circumferential surface of the control piston in the axial direction between the openings and between the working ports, while the openings comprise the working ports in the axial direction. Depending on the position of the control piston relative to the valve housing, the circumferentially extending groove can communicate with either the first or the second working port. At the same time, one of the two openings of the control piston communicates with the other working connection. In the case of two circumferentially extending grooves, a radial opening is provided on the control piston. This lies in the axial direction between the two circumferentially extending channels and between the working ports, the circumferentially extending grooves comprising the working ports. Depending on the position of the control piston relative to the valve housing one of the two circumferentially erstre- ckenden grooves communicate with the corresponding working port, while the connection of the other groove is interrupted with the other working port. At the same time the opening of the control piston communicates with the other work connection. In both cases, the control elements may be arranged on the control piston such that a middle position exists in which either both working connections only communicate with the inlet connection or with none of the supply connections. In this position of the control piston, the phase position of the device is maintained. Alternatively it can be provided that all pressure medium channels are formed within the control piston. In this case, a pressure medium channels separating wall can be integrally formed with the control piston. It is also conceivable to form the control piston as a substantially hollow cylindrical component, in the interior of which a separately manufactured insert component is provided, wherein the insert component forms the pressure medium channels in cooperation with an inner circumferential surface of the control piston.

In this embodiment, at least two separate pressure medium channels are formed within the control piston, which communicate via radial openings with the exterior of the control piston and thus can be connected to the working ports. The advantage of this embodiment lies in the fact that the valve housing can continue to be formed rotationally symmetrical and the pressure medium supply and removal is accomplished exclusively via the interior of the control piston. This considerably simplifies the pressure medium system, reduces space and costs.

Advantageously, each of the pressure medium passages can be connected to each of the working ports by appropriately positioning the control piston relative to the valve body.

This measure ensures that exactly two supply connections, namely an inlet connection and a discharge connection, are required in order to operate the device.

In an advantageous development of the invention it can be provided that the control piston is made of a plastic and is produced by means of an injection molding process.

For the injection molding process, casting molds are produced which already have all the typical geometric features of the finished component. The component is produced by filling the plasticized plastic into the mold and then curing the mass. In this case, the formation of undercuts or cavities by means of slide and / or Kernzugtechnolo gie, wherein the not filled with material spaces are filled with one or more moldings during the injection molding process. These moldings are elements of the injection mold and can be removed again from the workpiece after completion of the injection molding operation. Basically, the use of lost cores is conceivable.

It is also conceivable that the control piston consists of a metal and is produced by means of a metallurgical injection molding process, also known as metal injection molding (MIM). This process is analogous to the plastic injection molding process described above, in which case the material to be introduced into the mold consists of a mixture of fine metal powder and organic binders. The volume fraction of the metal powder is usually more than 50%. After the injection molding process, the organic binder and any lost cores are removed in a subsequent debindering process. This can be done either by thermal decomposition and subsequent evaporation or by solvent extraction. The remaining porous moldings are compacted by sintering under various shielding gases or under vacuum to give the components having the final geometric properties.

The advantage of this manufacturing method is that even structures that are not rotationally symmetrical to the longitudinal axis of the control piston, can be produced inexpensively and reliably.

In a device for the variable adjustment of the timing of gas exchange valves of an internal combustion engine with a control valve which is arranged in a valve receptacle of a surrounding construction, with a substantially hollow cylindrical valve housing, and axially displaceably arranged therein control piston, wherein at least two working ports and at least on the valve housing a first supply connection are formed, wherein via the supply connection the control valve either pressure medium supplied from a pressure medium pump or pressure medium can be discharged from the control valve in a tank, wherein the first supply port is formed by at least one radial opening in an outer circumferential surface of the valve housing, and is arranged in the axial direction between the working ports on the one side and a supply line on the other side, with which this communicates, the object is achieved in that the Supply line is designed at least in sections by a groove formed on an inner circumferential surface of the valve receptacle of the surrounding structure, which opens into the first supply port.

The device for the variable adjustment of the timing of gas exchange valves of an internal combustion engine comprises at least two mutually acting pressure chambers, by means of which the phase position between a camshaft and a crankshaft can be adjusted or held either. For this purpose, the pressure chambers pressure medium is supplied or derived from these. For controlling the pressure medium flows, a control valve is provided on which at least two working ports and at least two supply ports, in the form of an inlet and a drain port are formed. At least one of the supply ports is formed as at least one radial opening on an outer circumferential surface of the valve housing, wherein this connects in the axial direction of the control valve to the radially formed working ports. This supply connection communicates with a supply line which is designed at least in sections as formed on the valve receptacle of the surrounding construction, axially extending groove. The surrounding construction may be, for example, a rotor of a camshaft adjuster, a camshaft, a cylinder head cover or a cylinder head.

The groove can be formed cost-neutral during the manufacture of the surrounding structure. For example, this can be realized cost-neutral by simple modifications of the forming tool in the manufacture of a rotor made of sintered steel.

Advantageously, the working connections can also be designed as axially spaced radial openings in the valve housing, these being in the axial direction on the side facing away from the groove side of the supply terminal to connect to this. Furthermore, an axial supply connection can be provided, wherein at least two pressure medium channels are formed on the control piston, wherein each of the pressure medium channels is connected to one of the supply connections. Advantageously, at least one of the pressure medium channels is not rotationally symmetrical with respect to the longitudinal axis of the control valve. It can be provided that all pressure medium channels are formed within the control piston. In this case, the pressure medium channels from each other separating wall can be integrally formed with the control piston. Alternatively, the control piston may be formed as a substantially hollow cylindrical component, in the interior of which a separately manufactured insertion component is provided, wherein the insertion component forms the pressure medium channels in cooperation with an inner circumferential surface of the control piston.

Brief description of the drawings

Further features of the invention will become apparent from the following description and from the drawings, in which embodiments of the invention are shown in simplified form. Show it:

FIG. 1 shows very schematically an internal combustion engine,

2a shows a longitudinal section through a device for changing the timing of an internal combustion engine with a control valve according to the invention,

Figure 2b shows a cross section through the device of Figure 2a, without

Control valve, along the line IIB-IIB,

2c shows a longitudinal section through a control valve according to the invention, FIG. 3 shows a longitudinal section through a first embodiment of a control piston of a control valve according to the invention,

3a shows a cross section through the control piston shown in FIG. 3 along the line IIIA-IIIA, FIG.

3b shows a cross section through the control piston shown in Figure 3 along the line IMB-IIIB,

3c shows a cross section through the control piston shown in FIG. 3 along the line HIC-II IC, FIG.

FIG. 4 shows a longitudinal section through a second embodiment of a control piston of a control valve according to the invention,

4a shows a cross section through the control piston shown in Figure 4 along the line IVA-IVA,

4b shows a cross section through the control piston shown in FIG. 4 along the line IVB-IVB, FIG.

4c shows a cross section through the control piston shown in FIG. 4 along the line IVC-IVC, FIG.

4d shows a cross section through the control piston shown in FIG. 4 along the line IVD-IVD, FIG.

5 shows a longitudinal section through a third embodiment of a control piston of a control valve according to the invention,

5a shows a cross section through the control piston shown in FIG. 5 along the line VA-VA, FIG. 5b shows a cross section through the control piston shown in FIG. 5 along the line VB-VB, FIG.

5c shows a cross section through the control piston shown in FIG. 5 along the line VC-VC, FIG.

Figure 5d shows a cross section through the control piston shown in Figure 5 along the line VD-VD.

Detailed description of the drawing

1, an internal combustion engine 100 is sketched, wherein a piston 102 seated on a crankshaft 101 is indicated in a cylinder 103. The crankshaft 101 is in the illustrated embodiment via a respective traction drive 104 and 105 with an intake camshaft 106 and exhaust camshaft 107 in conjunction, with a first and a second device 1 for relative rotation between the crankshaft 101 and cam shafts 106, 107 can provide. Cams 108, 109 of the camshafts 106, 107 actuate an inlet gas exchange valve 110 or an outlet gas exchange valve 111. Equally, only one of the camshafts 106, 107 can be provided with a device 1, or only one camshaft 106, 107 can be provided Device 1 is provided.

FIGS. 2a, 2b show a first embodiment of a device 1 for variably setting the control times of gas exchange valves 110, 111 of an internal combustion engine 100. An actuating device 1a consists essentially of a drive wheel 5, a stator 2 and a rotor arranged concentrically with it following output element 3 called. The output element 3 consists of a wheel hub 4, on whose outer circumference five wings 6 are formed, which extend radially outward. Furthermore, the adjusting device 1a with a stepped Central bore 4b provided, in the assembled state of the device 1, a camshaft 3a, in the representation of Figure 2a, from the left, engages. In the mounted state of the device 1, this can, for example by means of a force, friction, form, or cohesive connection or by means of fastening mittein, rotatably connected to the camshaft 3a. In the illustrated embodiment, the device 1 is rotatably connected by means of a central screw 17 with the camshaft 3a.

The stator 2 is formed as a thin-walled sheet metal part, which consists of inner peripheral walls 7 and outer peripheral walls 8, which are connected to one another via side walls 9. The inner and outer circumferential walls 7, 8 extend essentially in the circumferential direction. About the inner peripheral walls 7, which bear against a cylindrical peripheral wall of the output element 3, the stator 2 is rotatably mounted on the driven element 3. Starting from the inner circumferential walls 7, the side walls 9 extend outwardly in a substantially radial direction and merge into the outer circumferential walls 8. By means of this structure, a plurality of, in the illustrated embodiment, five pressure chambers 10 are formed, which are sealed in a pressure-tight manner in the axial direction by the drive wheel 5 and a sealing disk 12.

The wings 6 are arranged on the outer circumferential surface of the driven element 3 such that exactly one wing 6 extends into each pressure chamber 10. The wings 6 are in the radial direction of the outer peripheral walls 8 of the stator 2 at. The width of the wings 6 is designed such that they rest in the axial direction on the drive wheel 5 and the sealing washer 12. As a result, each wing 6 divides a pressure chamber 10 into two counteracting pressure chambers 14, 15.

The stator 2 and the output element 3 are arranged within a cup-shaped housing 11, which encapsulates these components by the interaction with the drive wheel 5 pressure medium-tight. For this purpose, the open end of the housing 11 is oil-tightly connected to the drive wheel 5. The connection between the drive wheel 5 and the housing 11 can by means of a sealing joining process or be realized by the use of a sealant, not shown. In the illustrated embodiment, a circumferential circumferential weld joint 16a is provided.

On a bottom 13 of the housing 11, a concentric with the Zentraibohrung 4b arranged opening 16 is provided. A central screw 17 passes through the opening 16 and the central bore 4b, wherein a threaded portion of the central screw 17 engages in an internally threaded receptacle 18 of the camshaft 3a. The central screw 17 is further provided with a collar 19 which is supported in the assembled state of the central screw 17 either directly or indirectly on the output element 3 and thus rotatably connected to the camshaft 3a.

The region of the central screw 17, which is arranged within the output element 3, is designed as a control valve 20. This region of the central screw 17 extends within the central bore 4b, which acts as a valve seat 4a. The central screw 17 is provided with a blind hole-like receptacle 21, which extends to the camshaft facing away from the axial end of the central screw 17. The resulting cylindrical outer surface of the control valve 20 fulfills the function of a valve housing 22. In this case, the outer diameter of the valve housing 22 is adapted to the inner diameter of the driven element 3.

Furthermore, the valve housing 22 is provided with three groups of axially spaced-apart openings 23 a, b, c, via which the exterior of the valve housing 22 can communicate with the receptacle 21. Each group of openings 23a, b, c forms a pressure medium connection of the control valve 20, the camshaft-side group of openings 23a forming a supply connection 24 and the two other groups of openings 23b, c serving as working connections A, B. On an inner circumferential surface of the central bore 4b, two axially spaced annular channels 25a, 25b are formed in the form of radially inwardly open annular grooves, which are bounded by the valve housing 22 radially inwardly. Each of the ring channels 25a, 25b communicates with one of Working connections A, B. Within the output element 3, two groups of pressure medium lines 26 are formed, each of the pressure medium lines 26 on the one hand communicates with one of the pressure chambers 14, 15 and on the other hand with one of the annular channels 25a, 25b.

The supply port 24 of the valve housing 22 is formed in the illustrated embodiment as a feed port P, via the control valve 20 pressure medium is supplied from a pressure medium pump. The latter is in fluid communication with a supply line 27 formed between the central screw 17 and the camshaft 3a. The supply line 27 communicates via puncture bores 29 formed in the region of a camshaft bearing parts 28 and via a rotary feedthrough, not shown, with a pressure medium pump (also not shown).

Within the receptacle 21, a substantially hollow cylindrical trained control piston 30 is received axially displaceable. In this case, its outer diameter is adapted to the inner diameter of the receptacle 21 of the valve housing 22. The control piston 30 can be arbitrarily positioned by means of an actuating unit 31 via a push rod 32 against the force of a spring element 33 in the axial direction within the valve housing 22. On the outer circumferential surface of the control piston 30, three axially spaced annular grooves 39a, 39b, 39c are formed, wherein within the first annular groove 39a first radial openings 34a, within the second annular groove 39b second radial openings 34b, and within the third annular groove 39c third radial openings 34c are formed. The respective annular grooves 39a, 39b, 39c communicate with the interior of the control piston 30 via the radial openings 34a, 34b, 34c. Furthermore, fourth radial openings 35 are formed on the end of the control piston 30 remote from the camshaft. These form a second supply port 24, in the illustrated embodiment, a drain port T, from, can be removed via the pressure medium from the control valve 20.

About the tap holes 29 and the supply line 27, the inflow port P pressure medium can be supplied, which, depending on the position of the control piston 30 relative to the valve housing 22, to one of the two working ports A, B can be passed. The pressure medium passes via the working port A, B the corresponding annular channel 25a, 25b and the corresponding pressure medium line 26 to the respective pressure chamber 14, 15. By the supply of pressure medium to one of the pressure chambers 14, 15 this expands at the expense of the other pressure chamber 14, 15, wherein the pressure medium from the other pressure chamber 14, 15 via the corresponding pressure medium line 26, the corresponding annular channel 25a, 25b and the working port A, B enters the interior of the control valve 20. Within the control piston 30, the pressure medium reaches the drain port T and from there into the crankcase.

The arrangement of the pressure medium connections in the order Zulaufan- connection P, working port A, B, working port A, B in the axial direction, the possibility opens up the design of the pressure medium supply to the inlet port P considerably easier. Instead of realizing the supply line 27, as proposed in the prior art, by means of bores within the camshaft 3a and the output element 3, in this case the pressure medium at the interface between the valve housing 22 and a surrounding structure can be fed to the inlet port P.

In the illustrated embodiment, the outer diameter of the central screw 17 in the area between the tap holes 29 and the drive wheel 5 is made smaller than the outer diameter of the receptacle 18, whereby an annular space 38 a is formed. In the adjoining region, at least one axially extending groove 38b is provided, which connects the annular space 38a to the inlet port P. The groove 38b may be formed either on an inner wall of the surrounding structure, in the illustrated case the camshaft 3a and the driven element 3, or the outer surface of the valve housing 22.

In any case, these can be formed during the manufacturing process of the respective component cost neutral or with little additional effort. This is compared to the drilling described in the prior art. significantly simplifying the process while increasing the reject rate. Overall, this leads to a considerable cost reduction in the production of the device 1.

The application of such a control valve 20 is not limited to the illustrated embodiment. It is also conceivable to non-rotatably connect the driven element 3 to the camshaft 3a with a central screw 17, but other friction, mass, force or positive locking means, a control valve 20 being arranged within a central bore 4b of the driven element 3 ,

Likewise, the control valve 20 according to the invention may also be designed as a so-called. Plug-in or cartridge valve, which is arranged in a formed on a cylinder head or a cylinder head cover valve receptacle 4a.

In the case of central valve applications, the control valve 20, depending on the design of the device 1, for example, be arranged within the driven element 3, the camshaft 3a or an extension of the camshaft 3a. The inlet P and the outlet connection T may be arranged on the cam shaft facing or -abgewandten end or at different ends of the control valve 20. In this case, the radial supply connection 24 can serve both as supply P and as discharge connection T.

In the following, the training and the function of the control valve 20 according to the invention will be discussed in more detail.

A first embodiment of a control valve 20 according to the invention is shown in FIGS. 2c, 3, 3a-c. The outer diameter of the outer circumferential surface of the substantially hollow cylindrical control piston 30 is adapted to the inner diameter of the valve housing 22. Furthermore, three annular grooves 39a, b, c are provided on the outer lateral surface of the control piston 30. formed, wherein these are arranged spaced apart in the axial direction.

In the interior of the control piston 30, a first, central pressure medium channel 40 is formed, to the outside in the radial direction two second pressure medium channels 41 connect, extending in the cross section of the control piston 30 only within an angular segment less than 360 °. The pressure medium channels 40, 41 are separated from each other within the control piston 30 by walls 42, wherein the two second pressure medium channels 41 with respect to the longitudinal axis 36 of the control piston 30 are arranged opposite one another. The second pressure medium channels 41 communicate with the first and third annular grooves 39a, 39c via the first and third radial openings 34a, 34c, respectively. The first pressure medium channel 40 communicates via the second radial openings 34b with the second annular groove 39b. In this case, the second radial openings 34b offset from the first and the third radial openings 34a, 34c in the circumferential direction by 90 °, whereby it is achieved that the first pressure medium channel 40 exclusively with the second annular groove 39b and the second pressure medium channels 41 exclusively with the first and third annular groove 39a, 39c communicate. The first annular groove 39a is designed such that it communicates with the inlet port P relative to the valve housing 22 in each position of the control piston 30. Pressure medium entering the control valve 20 via the inlet port P passes into the first annular groove 39a and via the second pressure medium channels 41 to the third annular groove 39c. In this case, it is guided past the second annular groove 39b within the control piston 30, being prevented by the walls 42 from passing through the second radial opening 34b and thus into the second annular groove 39b.

Depending on the position of the control piston 30 relative to the valve housing 22, the pressure medium passes either via the first annular groove 39a to the working port B or via the third annular groove 39c to the working port A and from there to the respective pressure chamber 14, 15. At the same time off the respective other pressure chamber 14, 15 pressure medium to the other working port A, B and passes from there into the second annular groove 39 b. Via the second radial opening 34b, the pressure medium enters the central Pressure medium channel 40, from where it is directed in the axial direction to the drain port T and thus discharged from the control valve 20. In turn, the walls 42 prevent the pressure medium to be discharged from entering the first or third annular groove 39a, 39c.

The pressure medium channels 40, 41 are formed in this embodiment by an insert 43, which is made separately to the control piston 30 and is then arranged by means of a force, form, frictional or cohesive connection in the interior thereof.

Figures 4, 4a-d show a further embodiment of a control piston 30 of a control valve 20 according to the invention. This is largely identical to the control piston 30 shown in Figure 3. In contrast to the first embodiment, the separation between the pressure medium channels 40, 41 by means of one piece implemented with the control piston 30 running walls 42. In this embodiment, in turn, a first central pressure medium channel 40 is formed, followed by two opposing second pressure medium channels 41 in the radial direction. The second pressure medium channels 41 are again not rotationally symmetrical with respect to the longitudinal axis 36 of the control piston 30.

The first pressure medium channel 40 communicates on the one hand with the drain port T and on the other hand with the second annular groove 39b. The second pressure medium channels 41 communicate with both the first and the third annular groove 39a, 39c.

Figures 5, 5a-5d show a third embodiment of a control piston 30 of a control valve 20 according to the invention, which is identical to the first two embodiments in large parts. However, in this embodiment, two first and two second pressure medium channels 41 are arranged within the control piston 30. The first and second pressure medium channels 40, 41 in turn extend in the axial direction, but are arranged alternately in the circumferential direction in this embodiment. The pressure medium channels 40, 41 separating walls 42 are not, as in the first two Embodiments, designed as circular chords, but extend along two mutually perpendicular inner diameter of the control piston 30th

The second pressure medium channels 41 facing one another in the vertical direction in the illustrations 5a-5d in turn connect the first to the third annular groove 39a, 39c, while the horizontally opposed first pressure medium channels 40 connect the drain port T to the second annular groove 39b.

In addition to the one-piece design of the control valve 20 with a central screw 17 through which the device 1 is attached to the camshaft 3a, embodiments are also conceivable in which the device 1 is fixed by means of non-positive, positive or cohesive connections to a camshaft 3a and the Control valve 20 is designed as a separate component. Also conceivable is the use of a control valve 20 according to the invention as a so-called plug-in or cartridge valve, which is mounted in a valve seat 4a in the cylinder head or cylinder head cover, wherein the working ports A, B of the control valve 20 by suitable pressure medium lines and rotary feedthroughs led to the adjuster become.

Advantageously, the control piston 30 of the control valve 20 according to the invention or the insert 43 is produced by means of an injection molding process. It is conceivable here to produce the components from a suitable plastic by means of a plastic injection molding method or from metal by means of a powder metallurgical injection molding method, also known as a metel-injection molding method.

In both processes, moldings are produced which already have all the typical geometric features of the component in the negative. In the case of a plastic injection molding process, the plasticized plastic is introduced under pressure into these shaped bodies. Subsequently, the plastic is cured and can be removed from the reusable molding after this step. In the case of a powder metallurgical injection molding process, the shaped body is filled with a mixture of fine metal powder and organic binders during the injection molding process. Subsequently, the organic binders are removed, for example, by evaporation or solvent extraction, and the remaining blank is compacted by sintering under appropriate protective gases or vacuum to the finished control piston 30.

For the production of non-rotationally symmetrical components, injection molding processes have the advantage that the shaping of the components can be carried out without costly machining such as milling or drilling.

In the case of working ports A, B arranged directly adjacent in the axial direction, the non-rotationally symmetrical design of the pressure medium channels 40, 41 shown in the exemplary embodiments has the advantage that no additional openings have to be formed on the cylindrical jacket surface of the valve housing 22, and thus less constructive features must be realized. This leads to a considerable cost reduction in the production of the control valve 20.

In addition to the illustrated embodiments or analogous modifications, it is also possible to form one of the pressure medium channels 40, 41 within the control piston 30 and the other of the pressure medium channels 40, 41 on the outer circumferential surface of the control piston 30. In this case, the working ports A, B must be arranged at excellent positions of the valve housing 22 in the circumferential direction. Furthermore, an anti-rotation device between valve housing 22 and control piston 30 must be provided. reference numeral

1 device

1 a adjusting device

2 stators

3 output element

3a camshaft

4 wheel hub

4a valve seat

4b central hole

5 drive wheel

6 wings

7 inner peripheral wall

8 outer peripheral wall

9 side wall

10 pressure chamber

11 housing

12 sealing washer

13 floor

14 first pressure chamber

15 second pressure chamber

16 opening

16a welded joint

17 central screw

18 recording

19 fret

20 control valve

21 recording

22 valve housing

23a opening

23b opening

23c opening

24 supply connection 25a first annular channel

25b second ring channel

26 pressure medium line

27 Supply line 28 Camshaft bearing point

29 tap hole

30 control piston

31 actuator

32 push rod 33 spring element

34a first radial opening

34b second radial opening

34c third radial opening

35 fourth radial opening 36 longitudinal axis

38a annulus

38b groove

39a first annular groove

39b second annular groove 39c third annular groove

40 first pressure medium channel

41 second pressure medium channel

42 wall

43 insert

100 internal combustion engine

101 crankshaft

102 piston 103 cylinder

104 traction drive

105 traction drive

106 intake camshaft 107 exhaust camshaft

108 cams

109 cams

110 Intake gas exchange valve 111 Exhaust gas exchange valve

A work connection

B work connection

P inlet connection

T drain connection

Claims

claims

1. control valve (20) for a device (1) for the variable adjustment of the timing of gas exchange valves (110, 111) of an internal combustion engine (100) with

a substantially hollow cylindrical valve housing (22),

- And therein axially displaceably arranged control piston (30),

- Wherein on the valve housing (22) two working ports (A, B) and two supply ports (24) are formed, - each working port (A, B) by at least one radial opening (23b, 23c) in an outer circumferential surface of the valve housing (22 ) is trained,

- wherein the working ports (A, B) are spaced apart in the axial direction, - wherein at least two axially extending, mutually delimited pressure medium channels (40, 41) on the control piston (30) are formed,

- Each of the pressure medium channels (40, 41) in each position of the control piston (30) communicates with one of the supply terminals (24),

- Wherein each of the pressure medium channels (40, 41) can be connected by suitable positioning of the control piston (30) relative to the valve housing (22) with at least one of the working ports (A, B), characterized in that at least one of the pressure medium channels (40, 41 ) is not rotationally symmetrical with respect to the longitudinal axis (36) of the control valve (20) is formed.

Second control valve (20) for a device (1) for the variable adjustment of the timing of gas exchange valves (110, 111) of an internal combustion engine (100) with

a substantially hollow cylindrical valve housing (22), and a control piston (30) arranged axially displaceable therein,

- Wherein exactly two working ports (A, B), exactly one first and exactly one second supply port (24) on the valve housing (22) ausge- are formed, via one of the supply ports (24) the control valve (20) supplied pressure medium from a pressure medium pump and via the other supply port (24) pressure fluid from the control valve (20) can be discharged into a tank, - both working ports (A, B) and the first supply connection (24) are formed by at least one radial opening (23a, 23b, 23c) in an outer circumferential surface of the valve housing (22),

- wherein the working ports (A, B) and the first supply port (24) are spaced apart in the axial direction, - and wherein the first supply port (24) communicates with a supply line (27), characterized in that the working ports (A, B) are arranged directly adjacent in the axial direction and the first supply port (24) in the axial direction on the side of the supply line (27) to the working ports (A, B) connects.

3. Control valve (20) according to claim 2, characterized in that at least two axially extending, mutually delimited pressure medium channels (40, 41) on the control piston (30) are formed, each of the pressure medium channels (40, 41) in each position of the control piston (30) communicates with one of the supply ports (24), wherein each of the fluid passages (40, 41) can be connected to at least one of the working ports (A, B) by properly positioning the spool (30) relative to the valve housing (30) at least one of the pressure medium channels (40, 41) is not rotationally symmetrical with respect to the longitudinal axis (36) of the control valve (20) is formed.

4. Control valve (20) according to claim 1, characterized in that the working ports (A, B) are arranged directly adjacent in the axial direction.

5. Control valve (20) according to claim 1, characterized in that on the valve housing (22) exactly two working ports (A, B) are formed.

6. Control valve (20) according to claim 1, characterized in that on the valve housing (22) exactly two supply ports (24) are formed.

7. Control valve (20) according to claim 1, characterized in that one of the supply ports (24) is designed as a feed port (P), via which the control valve (20) pressure medium is supplied.

8. Control valve (20) according to claim 1, characterized in that one of the supply connections (24) is designed as a discharge connection (T) can be discharged via the pressure medium from the control valve (20) to a tank can the.

9. Control valve (20) according to any one of claims 1 or 3, characterized in that each of the pressure medium channels (40, 41) connected by suitable positioning of the control piston (30) relative to the valve housing (22) with each of the working ports (A, B) can be.

10. Control valve (20) according to any one of claims 1 or 3, characterized in that all the pressure medium channels (40, 41) are formed within the control piston (30).

11. Control valve (20) according to claim 10, characterized in that one of the pressure medium channels (40, 41) from each other separating wall (42) is formed integrally with the control piston (30).

12. Control valve (20) according to claim 10, characterized in that the control piston (30) is designed as a substantially hollow cylindrical component, in the interior of which a separately manufactured insert component (44) is provided is, wherein the insert member (44) in cooperation with an inner circumferential surface of the control piston (30) the pressure medium channels (40, 41) is formed.

13. Control valve (20) according to any one of claims 1 or 3, characterized in that at least one pressure medium channel (40, 41) on an outer circumferential surface of the control piston (30) is formed.

14. Control valve (20) according to any one of claims 1 or 2, characterized in that the control piston (30) consists of a metal and is produced by means of a metallurgical injection molding process.

15. Control valve (20) according to one of claims 1 or 2, characterized in that the control piston (30) consists of a plastic and is manufactured by means of an injection molding process.

16, control valve (20) according to claim 2, characterized in that the supply line (24) at least in sections as an annular space (38 a) between the valve housing (22) and the surrounding structure (3) is formed

17, control valve (20) according to claim 2, characterized in that the supply line (24) at least partially as at least one, on the outer circumferential surface of the control piston (30) provided, in the first supply port (24) opening groove (38b) is formed.

18. Device (1) for the variable adjustment of the timing of gas exchange valves (110, 111) of an internal combustion engine (100) with

a control valve (20), which is arranged in a valve receptacle (4a) of an ambient construction (3), with a substantially hollow-cylindrical valve housing (22), and a control piston (30) arranged axially displaceable therein, wherein at least two working connections (A, B) and at least one first supply connection (24) are formed on the valve housing (22),

- Via the supply port (24) the control valve (20) either pressure medium supplied from a pressure medium pump or pressure medium from the control valve (20) can be discharged into a tank,

wherein the first supply connection is formed by at least one radial opening in an outer circumferential surface of the valve housing.

- And in the axial direction between the working ports (A, B) on the one side and a supply line (24) is arranged on the other side, with which this communicates, characterized in that

- The supply line (24) at least partially by a formed on an inner circumferential surface of the valve receptacle (4a) of the surrounding structure (3) groove (38b) is executed, which in the first supply port (24) opens.