WO2006061071A1

WO2006061071A1 - Control valve

Info

Publication number: WO2006061071A1
Application number: PCT/EP2005/011899
Authority: WO
Inventors: Jens Hoppe; Martin Stief; Markus Kinscher
Original assignee: Schaeffler Kg
Priority date: 2004-12-07
Filing date: 2005-11-08
Publication date: 2006-06-15
Also published as: JP4982868B2; CN101072927A; KR101239610B1; DE102004058767A1; JP2008523294A; EP1825106B1; KR20070085766A; EP1825106A1; CN101072927B; US20080245324A1

Abstract

The invention relates to a control valve (101) for the control of a hydraulic device for changing the control times of gas exchange valves in an internal combustion engine, whereby the control valve (101) is lodged in a valve housing (106) and an elastic seal element (124) is provided at the axial end thereof. The application of the elastic seal element (124) secures function by prevention of leakage flow between the pressure medium channels (113) and the pressure medium channels (113) and the drain connector (T). Also disclosed is an elastic seal element (124) embodied as a sealing ring with two conical regions (129, 131).

Description

Name of the invention

control valve

description

Field of the invention

The invention relates to a sealing element according to the preamble of claim 1 and a control valve for controlling the inflow and outflow of pressure medium to a device for changing the timing of an internal combustion engine according to the preamble of claim 4.

Background of the invention

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 electrohydraulic or electric valve actuations are provided. Furthermore, it has been found to be advantageous during the operation of the internal combustion engine to be able to influence the opening and closing times of the gas exchange venti Ie. 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 relationship 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. The drive wheel may be designed as a chain, belt or gear in the case of a not arranged on the crankshaft camshaft adjuster and is driven by means of a chain, a belt or a gear drive from the crankshaft. 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 now one pressure chamber is acted upon by pressure medium while the other pressure chamber is connected to a tank, the piston shifts in the axial direction. The axial displacement of the piston is translated by the helical toothing into 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 rotary piston adjuster. In these, the drive wheel is rotatably connected to a stator. The stator and a rotor are arranged concentrically with each other, wherein the rotor is positively, positively or materially, 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 connected. 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, dividing each cavity into two pressure chambers. By Targeted 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 field of the internal combustion engine, determines a desired value of the relative phase angle between the camshaft and the crankshaft. Sensors, such as Hall sensors, the actual value of the phase angle and a deviation of the actual value is determined by the target value. Subsequently, a control command is passed to an actuating unit of the control valve, which controls the inflow and outflow of pressure medium to the various pressure chambers and thus the adjustment of the phase angle of the camshaft.

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 a control valve, usually a 4/3-proportional valve. A valve housing is provided with one connection each for the pressure chambers (working connection), one connection to the pressure medium pump and at least one connection to one Tank provided. 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 actuating unit, for example an electromagnetic or hydraulic actuating unit, counter to the spring force of a spring element. The control piston is further provided with annular grooves and control edges, whereby the individual pressure chambers can be selectively connected to the pressure medium pump or the tank. Likewise, a position of the control piston can be provided, in which the pressure medium chambers are separated from both the pressure medium pump and the pressure medium tank.

Such control valves can be designed as a central valve or as a plug-in valve. In the case of a central valve, this is arranged within the camshaft or an extension of the camshaft in the region of the camshaft adjuster. In the case of a plug-in valve, an environmental construction of the internal combustion engine is provided with a valve receptacle into which the control valve is inserted. In the lateral surface of the usually designed as a bore valve receiving pressure medium lines are formed, which communicate with the pressure medium connections of the control valve. Such an environment construction may be, for example, a cylinder head or a cylinder head cover.

In DE 102 23 431 B4 such a device is shown with a control valve in plug-in design. The device consists of a camshaft-fixed output unit, a driven by the crankshaft drive unit and two side covers. The drive unit is arranged coaxially with the output unit and provided with a plurality of circumferentially spaced recesses. The recesses are pressure-sealed by the drive unit, the output unit and the side covers and thus form pressure chambers. In each pressure chamber, a wing extends, each wing is arranged in a formed on the output unit vane groove. Each wing divides a pressure chamber into two opposing pressure chambers. The pressure chambers communicate via into a camshaft introduced pressure medium lines by means of rotary unions with introduced in a cylinder head or a cylinder head cover further pressure medium lines.

The further pressure medium lines can be connected by means of a control valve, in this case a 4/3-way valve, optionally with a pressure medium reservoir or a pressure medium pump. The control valve consists of an actuator and a valve body. The valve body is surrounded by an adapter sleeve, which is arranged ceiling in a bore of a cylinder head. In the adapter sleeve three axially and circumferentially zueinan- spaced-spaced radial openings are introduced, which serve as pressure medium connections. A fourth pressure medium connection is formed in the axial direction on the end face of the valve body facing away from the setting unit. Each radial opening is connected via a respective riser channel with a pressure medium line. Pressure medium passes via a pressure medium line to the axial radial direction in the axial direction, from there into the interior of the sleeve, wherein the pressure medium is guided depending on the control position of the control valve to one of the two other radial openings. From there, the pressure medium passes via a further riser to a pressure medium line, which communicates with one of the rotary unions and in the following with a first group of pressure chambers.

In an analogous manner, pressure medium passes from a second group of pressure chambers via the rotary feedthrough and pressure medium lines to a further riser, which opens into the third radial opening. From there, the pressure medium passes via the control valve to the axial outlet connection. The risers are formed as formed in the bore in the cylinder head cover, the adapter sleeve open grooves. Furthermore, the risers are sealed against each other, characterized in that the outer diameter of the adapter sleeve is adapted to the inner diameter of the bore. In this embodiment, the pressure medium lines communicating with the riser lines are formed as grooves introduced into the cylinder head cover and open toward the cylinder head. In order to allow the pressure medium displaced from the pressure chambers to flow away, the cylinder head is provided with a drainage bore which is coaxial with the bore formed in the cylinder head cover. In order to avoid leakage between the risers and the drain hole, the inner diameter of the bore and the drain hole are identical and the adapter sleeve extends at least partially into the adapter bore. The adapter sleeve is now sealingly against the lateral surface of the drain hole, whereby a flow of the pressure medium from the riser pipes is prevented via the drain hole in the interior of the cylinder head. Small misalignment of the holes causes damage to the adapter sleeve during assembly, which may result in loss of sealing between the components.

In order to ensure the sealing function between the riser channels and the drain hole exact coaxial alignment of the bore to the drain hole and a precise adjustment of the adapter sleeve diameter to the inner diameter of the drain hole is necessary. This is only possible with great effort due to the tolerances which inevitably occur in the production process of the individual components.

Summary of the invention

The invention has for its object to avoid these disadvantages and to propose a sealing concept for a control valve, which is not susceptible to tolerances occurring in the system. Furthermore, a sealing element is proposed which finds use in this sealing concept.

A control valve for controlling the inflow and outflow of pressure medium to a device for changing the control times of an internal combustion engine consists, inter alia, of a substantially cylindrically designed valve housing, are formed on the pressure medium connections and arranged within the valve housing, axially displaceable control piston. In this case, depending on the position of the control piston, a connection between the various pressure medium connections can be produced or separated. The valve housing is arranged inside a valve receptacle, wherein the inlet Insertion depth of the valve housing is limited in the valve seat by a formed in the valve seat axial stop. The object is achieved in that the axial stop is formed as a circular or annular wall extending radially from an inner circumferential surface of the valve receiving radially inwardly and that between the valve housing and the axial stop of the valve seat a sealing element is arranged.

Such a control valve consists of a cylindrical valve housing and an axially displaceably arranged in the valve housing control piston. The valve housing is provided with radial openings, which serve as pressure medium connections. By means of an actuating unit, the control piston can be brought within the valve housing in any position between two end stops. In this case, the control piston connects or disconnects different pressure medium connections depending on the relative position to the valve housing. The spool can be in direct contact with the valve body. Another possibility, as shown in DE 102 23 431, is to provide a hollow running control sleeve between the valve housing and the control piston. The inner diameter of the control sleeve is the outer diameter of the control piston and the outer diameter of the control sleeve is adapted to the inner diameter of the valve housing. Furthermore, the outer circumferential surface of the control sleeve is provided with a plurality of annular grooves which communicate on the one hand with the pressure medium connections and on the other hand via radial openings with the interior of the control sleeve. By axial displacement of the control piston connections between the annular grooves, and thus the pressure medium connections, and optionally with an axial pressure medium connection can be made or separated.

Such control valves are arranged in valve receptacles in which pressure medium channels are formed, which communicate with the pressure medium connections. The pressure chambers of the camshaft adjuster are selectively connected to a pressure medium pump or a pressure medium reservoir via the pressure medium channels. Such valve receptacles may be formed for example in a cylinder head or a cylinder head cover. In this case one speaks of a plug-in valve. Another option is to use the control valve as the central valve. In this case, it is arranged in a valve receptacle in the camshaft and rotates during operation of the internal combustion engine with the camshaft. In both cases, the valve seat is designed as a cylindrical bore. The outer diameter of the valve housing is adapted to the inner diameter of the bore, whereby the pressure medium connections are sealed against each other. Within the bore an axial stop for the valve body is provided. The axial stop can be designed as a wall delimiting the bore. Also conceivable is a diameter constriction of the bore. In this case, the bore is stepped in cross-section, whereby a ring portion is formed, which serves as an axial stop for the valve housing. Furthermore, a sealing ring is provided between the axial stop and the valve housing, which prevents leakage currents in the axial direction.

Through this approach, the described in DE 102 23 431 radial sealing ring location is moved in the axial direction, whereby the effects of tolerances in the dimensions of the control valve are less critical.

In an advantageous development of the invention, it is provided that the axially stop-side front end of the valve housing is formed with an area reduced in the outer diameter, wherein the sealing element is arranged at least partially in the area reduced in outer diameter. Furthermore, the sealing element is designed as a sealing ring with an outer and an inner circumferential surface.

The reduced in outer diameter range facilitates the installation of the sealing element and the control valve in the valve seat. The inner diameter of the sealing element designed as a sealing ring is adapted to the outer diameter of the reduced outer diameter range. The sealing ring is placed in this area on the control valve and positioned together with him in the valve seat. Thus, due to the leadership and Centering, which experiences the sealing element by means of the control valve, prevents incorrect assembly and the sealing effect produced process reliable.

Furthermore, it can be provided that the sealing element consists of an elastomer. The sealing ring is located in the case of a valve housing with an outer diameter reduced area at the axial stop end on the outer circumferential surface of this area. Furthermore, it is clamped in the axial direction of the valve housing and the axial stop. During assembly, the sealing ring is pressed against the axial stop by the valve body. In this case, this deforms elastically, wherein a deformation is prevented radially inwardly through the valve housing. The elastic deformation thus receives a "preferential direction", namely radially outwards, against the inner lateral surface of the valve seat, which increases the sealing effect or achieves it much earlier, a further advantage in the use of an elastic sealing ring being that its deformability axial tolerances can be compensated.

The elastomer may be, for example, a fl our rubber or an acrylonitrile-butadiene rubber. These materials are very suitable because of their high resistance to environmental influences in internal combustion engines, such as high temperatures, and in contact with engine oil.

In a further concretization of the invention, the valve seat is composed of a first and a second bores, wherein the bores are formed in different surrounding constructions, are arranged at least approximately coaxially and are designed to follow one another. An example of such an embodiment is the valve seat shown in DE 102 23 431. In a cylinder head and a cylinder head cover a bore is executed in each case. The two holes are arranged so that they are at least approximately coaxial with each other when the cylinder head cover is mounted on the cylinder head. In one development of the invention, the axial stop can be formed at the interface of the two surrounding structures. In this embodiment, the inner diameter of the second bore is made smaller than that of the first bore. At the interface between the two holes so a step is formed. The advantage of this variant is the low production costs, since the stage is realized by the juxtaposition of two holes of different inner diameter.

Alternatively, the axial stop is formed in the second bore in the insertion direction of the control valve. The advantage is that the stepped course of the bore can be designed such that the sealing element can abut against the boundary surface of the two surrounding structures on the inner lateral surfaces of the bores.

Since in this embodiment of the invention, the outer surface of the valve housing no longer exerts the sealing function at the interface of the surrounding structures, the inner diameter of the second bore at the interface between the surrounding structures can be made larger than the inner diameter of the first bore and thus as the outer diameter of the valve housing. Thus, even with a slight offset of the holes to each other, the non-destructive installation of the control valve is secured in the valve seat.

Furthermore, it is provided that the axial stop arranged and the sealing element is formed such that the sealing element bears against the interface of the two surrounding structures on the valve seat. Any existing leakage paths, caused by deviating from the rectangular shape edges are thus reliably blocked by the elastic deformation of the sealing element.

In an advantageous development of the invention, the transition region of the valve housing to the diameter-reduced region is at least partially conical. Furthermore, the sealing element is on its Innenmantelflä- provided with a first conical region, wherein this is adapted to the transition region of the valve housing.

The valve housing consists of a first and a second cylindrical portion. The first cylindrical portion is sealingly against the inner wall of the first bore. The second area is the area reduced in outer diameter. At the transition from the first to the second region, a conical transition region is formed. In this case, the entire diameter reduction can be bridged by means of the conical region. It is also conceivable that starting from the first region, the valve housing extends radially inwards in a step-like manner, before it merges into the conical region, which terminates in the area reduced in the outer diameter. The sealing ring is arranged in this transitional area, wherein its contour resting on the valve housing is adapted to the contour of the valve housing, in particular of the conical area. During assembly of the control valve in the valve seat, the valve housing exerts a force on the sealing ring. Due to the non-parallel to the axial stop pressure surface of the sealing ring is acted upon in both the axial and in the radial direction with a force. As a result, a better sealing effect in the radial direction is achieved.

In an advantageous development of the invention, it is provided that the outer circumferential surface of the sealing element is provided with a second conical region on the end face resting against the axial stop, so that an annular cavity is created between the sealing element and the axial stop. If, for example, larger axial tolerances have to be compensated, and thus the valve is positioned further inside the valve receptacle, then the sealing ring can avoid the cavity while maintaining its sealing function. Larger manufacturing tolerances can be compensated and thus costs can be saved.

Furthermore, a sealing element in the form of a sealing ring for sealing an axial end face of a control valve of a device for changing the Values of gas exchange valves proposed with an inner circumferential surface and an outer circumferential surface. According to the invention the object is achieved in that the inner and the outer circumferential surface is provided at each one of these annular edges with a conical region. In this case, the two conical regions are formed on mutually offset in the axial direction annular edges of the sealing ring. One of the conical regions is provided for engagement with a conical region of a component, which is intended to seal the sealing ring against a second component. It is especially thought of a sealing mounting of a component within a bore, wherein the sealing ring is acted upon by an axially directed force. The conical contact surface of the component translates the axially directed force into a radial and an axial force component, whereby the sealing ring is deformed in the radial direction and thus the sealing effect is increased. Due to the conical design of a further annular edge an annular cavity is held, in which the sealing ring can escape under the action of force. Through this cavity thus large axial tolerances can be compensated without affecting the sealing effect.

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:

1 shows a longitudinal section through a device for changing the timing of an internal combustion engine with pressure medium circuit,

FIG. 2 shows a cross section through the device shown in FIG. 1 along the line H-II,

FIG. 3 shows a longitudinal section through a control valve mounted in a valve receptacle according to a first sealing concept according to the invention, 4 shows a cross section along the line IV-IV of Figure 3,

5 shows a longitudinal section through a control valve mounted in a valve receptacle according to a second sealing concept according to the invention, FIG.

FIG. 6 shows a cross section along the line VI-VI from FIG. 5,

FIG. 7 shows a longitudinal section through a sealing ring according to the invention,

8 shows a cross section along line VIII-VIII of Figure 7.

Detailed description of the invention

Figures 1 and 2 show a device 1 for changing the timing of an internal combustion engine. The device 1 consists essentially of a stator 2 and a rotor 3 arranged concentrically therewith. A drive wheel 4 is connected in a rotationally fixed manner to the stator 2 and, in the illustrated embodiment, is designed as a chain wheel. Also conceivable are embodiments of the drive wheel 4 as a belt or gear. The stator 2 is rotatably mounted on the rotor 3, wherein on the inner circumferential surface of the stator 2 in the illustrated embodiment, five circumferentially spaced recesses 5 are provided. The recesses 5 are bounded in the radial direction by the stator 2 and the rotor 3, in the circumferential direction of two side walls 6 of the stator 2 and in the axial direction by a first and a second side cover 7, 8. Each of the recesses 5 is sealed pressure-tight manner in this way. The first and second side covers 7, 8 are connected to the stator 2 by means of connecting elements 9, for example screws. On the outer circumferential surface of the rotor 3 axially extending vane grooves 10 are formed, wherein in each vane groove 10, a radially extending vane 11 is arranged. In each recess 5, starting from the respective wing groove 10, a wing 11 extends, wherein the wings 11 in the radial direction on the stator 2 and in the axial direction of the side covers 7, 8 abut. Each wing 11 divides a recess 5 in two mutually opposed pressure chambers 12, 13. In order to ensure a pressure-tight abutment of the wings 11 on the stator 2, 11 leaf spring elements 15 are mounted between the groove bases 14 of the wing grooves 10 and the wings, which the wing 11 in Apply a force to the radial direction.

By means of first and second pressure medium lines 16, 17, the first and second pressure chambers 12, 13 can be connected via a control valve 18 to a pressure medium pump 19 or a tank 20. As a result, a positioning drive is formed, which allows a relative rotation of the stator 2 relative to the rotor 3. It is provided that either all the first pressure chambers 12 are connected to the pressure medium pump 19 and all the second pressure chambers 13 to the tank 20 and the opposite configuration. When the first pressure chambers 12 are connected to the pressure medium pump 19 and the second pressure chambers 13 are connected to the tank 20, the first pressure chambers 12 expand at the expense of the second pressure chambers 13. This results in a displacement of the wings 11 in the circumferential direction, in the direction shown by the arrow 21. By moving the vanes 11, the rotor 3 is rotated relative to the stator 2.

In the illustrated embodiment, the stator 2 is driven by the crankshaft by means of a chain drive (not shown) acting on its drive wheel 4. Also conceivable is the drive of the stator 2 by means of a belt or gear drive. The rotor 3 is non-positively, positively or materially, for example, by means of press fit or by a screw connection by means of a central screw, connected to a camshaft, not shown. From the Relatiwerdrehung of the rotor 3 relative to the stator 2, as a result of the supply and discharge of pressure medium to or from the pressure chambers 12, 13, resulting performs a phase shift between camshaft and crankshaft. By selective introduction and discharge of pressure medium into the pressure chambers 12, 13, the control times of the gas exchange valves of the internal combustion engine can thus be selectively varied.

The pressure medium lines 16, 17 are executed in the illustrated embodiment as channels within the rotor 3, which extend from a central bore 22 of the rotor 3 to the outer circumferential surface. Within the central bore 22, a central valve, not shown, can be arranged, via which the pressure chambers 12, 13 can be selectively connected to the pressure medium pump 19 and the tank 20. Another possibility is to arrange a pressure medium distributor within the central bore 22, which connects the pressure medium lines 16, 17 via pressure medium channels and annular grooves with pressure medium connections A, B, P, T of an externally mounted control valve 18.

The substantially radially extending side walls 6 of the recesses 5 are provided with formations 23 which extend in the circumferential direction in the recesses 5. The formations 23 serve as a stop for the wings 11 and ensure that the pressure chambers 12, 13 can be supplied with pressure medium, even if the rotor 3 occupies one of its two extreme positions relative to the stator 2, in which the wings 11 on one of the side walls. 6 issue.

With insufficient supply of pressure medium of the device 1, for example, during the starting phase of the internal combustion engine, the rotor 3 is due to the alternating and drag moments, which exerts the camshaft on this uncontrolled relative to the stator 2 moves. In a first phase, the reaction torques of the camshaft urge the rotor 3 relative to the stator 2 in a circumferential direction, which is opposite to the direction of rotation of the stator 2 until they abut against the side walls 6. In the following, the alternating moments, which exerts the camshaft on the rotor 3 to a swinging back and forth of the rotor 3 and thus the wing 11 in the recesses 5, to at least one of the pressure chambers 12, 13 is completely filled with pressure medium. This leads to higher wear and noise developments in the device 1. To prevent this, a locking element 24 is provided in the device 1. For this purpose, a cup-shaped piston 26 is arranged in an axial bore 25 of the rotor 3, which is acted upon by a first spring 27 in the axial direction with a force. The first spring 27 is supported in the axial direction on one side on a venting element 28 and is arranged with its axial end facing away from inside the pot-shaped executed piston 26. In the first side cover 7 a link 29 is formed such that the piston 26 can engage in at least one relative position of the rotor to the stator in this. In this position, the piston 26 is urged in the backdrop 29 in insufficient supply of pressure medium of the device 1 by means of the first spring 27. In this state, the rotor 3 is locked relative to the stator 2 in this position. Notably, the locking position corresponds to the position to be assumed during the start of the internal combustion engine. Furthermore, means are provided to push the piston 26 with sufficient supply of the device 1 with pressure medium in the axial bore 25 and thus cancel the lock. This is usually accomplished with pressure medium, which is conducted via not shown pressure medium lines into a recess 30 which is formed on the cover-side front end of the piston 26. In order to be able to derive leakage oil from the spring chamber of the axial bore 25, the venting element 28 is provided with axially extending grooves, along which the pressure medium can be directed to a bore in the second side cover 8.

In Figure 1, the pressure medium circuit 31 is also shown. From a tank 20 by means of a pressure medium pump 19, an inlet port P of a control valve 18 is supplied with pressure medium. At the same time pressure medium is conducted from the control valve 18 into the tank 20 via a drain port T. The control valve 18 also has two working ports A ₁ B, the first working ports A communicating with the first pressure chambers 12 and the second working ports B communicating with the second pressure chambers 13. By means of an electromagnetic actuator 32, against the spring force of a second Spring 33 acts, the control valve 18 can be placed in three positions. In a first position of the control valve 18, which corresponds to a de-energized state of the actuator 32, the first working port A, and thus the first pressure chambers 12, connected to the drain port T. At the same time, the inflow port P communicates with the second working port B, and thus with the second pressure chambers 13. Thus, while pressure fluid flows from the first pressure chambers 12, pressure fluid is directed to the second pressure chambers 13, whereby the vanes 11 are displaced in the circumferential direction. This results in a change in the phase position between the rotor 3 and stator 2 and thus between the camshaft and crankshaft.

In a middle position, both the first working port A and the second working port B are separated from both the inflow port P and the outflow port T. Pressure medium can neither be added to the pressure chamber 12, 13 nor discharged, and the phase angle of the camshaft relative to the crankshaft is maintained. An alternative possibility is to connect both working connections A ₁ B to the inlet connection P in order to compensate for leakage occurring in the device 1.

In a third position of the control valve 18, the inlet connection P is connected to the first working connection A and consequently to the first pressure chamber 12, while the second pressure chamber 13 is connected to the outlet connection T via the second working connection B. Analogous to the first control position of the control valve 18, the phase angle of the camshaft is changed to the crankshaft, only in the opposite direction.

FIG. 3 shows a control valve 101 according to the invention, which has an adjusting device 102, a substantially hollow-cylindrical control housing 103, a likewise substantially hollow-cylindrical control piston 104 and a likewise substantially hollow cylindrical valve housing 105. The control housing 103 is arranged stationarily within the valve housing 105. In this case, the inner diameter of the valve housing 105 is adapted to the outer diameter of the control housing 103. Furthermore, the control piston 104 is axially displaceable within the control housing 103, wherein the outer diameter of the control piston 104 is adapted to the inner diameter of the control housing 103. The valve housing 105 is disposed within a valve receptacle 106. The valve receptacle 106 is composed of two bores 107, 108, which are formed in two surrounding structures 109, 110. The first surrounding structure 109 is attached to the second surrounding structure 110, and the bores 107, 108 are formed and arranged such that they are at least approximately coaxial with each other. The inner diameter of the second bore 108 is made smaller than the inner diameter of the first bore 107 in this embodiment. As a result, an annular axial stop 111 which limits the insertion depth of the control valve 101 is formed at the interface between the first surrounding structure 109 and the second surrounding structure 110. The valve housing 105 is provided at its axial stop end with an outer diameter reduced portion 112, wherein the outer diameter of the outer diameter reduced portion 112 is smaller than the inner diameter of the second bore 108. Furthermore, in this embodiment, the transition to the outer diameter-reduced portion 112 is made stepwise. The valve housing 105 passes through the first bore 107 and, with its diameter-reduced area 112, at least partially extends into the second bore 108. The outer diameter of the valve housing 105 is adapted to the inner diameter of the valve seat 106.

At the interface between the first and the second surrounding structure 109, 110 three pressure medium channels 113 are formed. The pressure medium channels 113 are in the form of grooves which are introduced either in the surface of the first or second surrounding structure 109, 110. Each of the pressure medium channels 113 opens into a master groove 114a, 114b, 114p which are formed in the lateral surface of the first bore 107. The stiffening grooves 114a, 114b, 114p are offset relative to one another in the circumferential direction of the first bore 107 and extend essentially in the axial direction of the valve housing 105. Each of the stiffening grooves 114a, 114b, 114p communicates via one in each Valve housing 105 introduced radial opening 115a, 115b, 115p, which serve as working ports A, B and inlet port P, with the interior of the valve housing 105th

The outer circumferential surface of the control housing 103 is provided with three mutually axially offset annular grooves 116a, 116b, 116p. The Steignuten 114a, 114b, 114p, the radial openings 115a, 115b, 115p and the annular grooves 116a, 116b, 116p are arranged such that the first Steignut 116a means of the first radial opening 115a exclusively with the first annular groove 116a, the second Stutzut 114b means the second radial opening 115b exclusively communicates with the second annular groove 116b and the third master groove 114p communicates with the third annular groove 116p by means of the third radial opening 115p. Furthermore, each of the annular grooves 116a, 116b, 116p communicates with the interior of the control housing 103 by means of openings 117a, 117b, 117p formed in the groove base thereof. The control piston 104 arranged inside the control housing 103 can be moved against the force by means of an actuating device 102 via a pushrod 119 a first spring element 120 are axially displaced within the control housing 103. The control piston 104 is provided with two control sections 121, wherein the outer circumference of the control sections 121 is adapted to the inner circumference of the control housing 103. The control sections 121 may be manufactured as separate components and mounted on the control piston 104 or, as shown in FIG. 3, may be integrally formed therewith. Outside the control sections 121, the outer diameter of the control piston 104 is made smaller. The control sections 121 are designed and arranged on the control piston 104 such that a fourth annular groove 122 is formed, which connects the first or the second annular groove 116a, 116b with the third annular groove 116p, depending on the position of the control piston 104 relative to the control housing 103. Furthermore, the control piston 104 is open at its end-side end, on which the first spring element 120 engages. As a result, a connection between the interior of the control piston 104 and the second bore 108 is produced and thus a drain port T is shown. Fourth openings 123 are formed on the plunger rod-side end of the control piston 104, as a result of which the interior of the control piston 104 is hydraulically connected to the outer end of the control piston 104. ßeren of the control piston 104 is connected. The fourth openings 123 are in the illustrated embodiment, outside the fourth annular groove 122 in the outer circumferential surface of the control piston 104th

By means of the adjusting device 102, the control piston 104 can be moved via the push rod 119 within the control housing 103 in any position between two maximum values. In this case, the first spring element 120 has a restoring effect on the control piston 104. As adjusting device 102, for example, hydraulic adjusting devices or, as in the illustrated embodiment, electromagnetic adjusting devices in question. The electromagnetic actuator 102 consists of a coil which is arranged in a magnetic field of one or more permanent magnets. The coil is associated with a power supply unit, via which it can be energized with an electric current. Several possibilities of excitation of the coil are conceivable. One possibility would be, for example, to vary the position of the coil within the magnetic field by variable current levels, with high currents corresponding to a high deflection and low currents to a low deflection. It is also conceivable to excite the coil by means of pulsed currents. For example, a square wave voltage between the values OV and a constant voltage V ₀ can be applied to the electrical poles of the coil. The deflection of the coil and thus of the control piston 104 is now determined by the ratio of the time intervals in which the voltage V ₀ or no potential difference is applied to the electrical poles. The larger the voltage-free intervals, the smaller the deflection of the coil. The longer the time intervals are in which the voltage V ₀ is present, the greater the deflection.

In the illustrated embodiment in Figure 3 and Figure 4, a 4/3-way valve with four pressure fluid connections A, B, P, T is shown, wherein the control piston 104 may be located substantially in three control states. However, the invention is not limited to such a four / three-way valve, but there are quite well application examples conceivable in which, for example, a 4/4-way valve or other valves are used.

The following is an example of the function of the 4/3-way valve will be described. About one of the pressure medium channels 113, the third Steignut 114p is pressurized with pressure medium. In each control position of the control valve 101, the pressure medium passes via the third radial opening 115p, the third annular groove 116p and the third openings 117p in the fourth annular groove 122. In a first state of the control valve 101, which corresponds to a de-energized state of the actuator 102, the control piston 104th moved by the spring force of the first spring element 120 in a maximum deflection position in the direction of the adjusting device 102. In this control position, the fourth annular groove 122 communicates via the first openings 117 a, the first annular groove 116 a and the first radial opening 115 a with the first Steignut 114 a, from where the pressure medium to the first pressure chambers 12 is passed.

In a second control position of the control valve 101, in which the adjusting device 102 is energized maximally, the control piston 104 is deflected maximally in the direction of the first spring element 120. In this case, the fourth annular groove 122 communicates with both the third openings 117p and the second openings 117b. Pressure medium now passes via the second annular groove 116b, the second radial opening 116b and the second master groove 114b to the corresponding pressure medium passage 113 and from there to the second pressure chambers 13. In a third state, the control piston 104 is in a middle position in the fourth Annular groove 122 communicates only with the third openings 117p. In this case, the pressure medium flow to both pressure chambers 12, 13 is prevented. Alternatively, it is also conceivable that in this middle position the fourth annular groove 122 communicates with the first, the second and the third openings 117a, 117b, 117p. Pressure medium is passed in this case to both pressure chambers 12, 13, whereby leakage compensated and the phase position between the camshaft and crankshaft is kept reliable. In the first and second control positions, the control sections 121 completely release or completely close the respective openings 117a, 117b. Of course, the control piston 104 can be positioned any position between these two extremal, whereby the openings 117a, 117b are only partially opened or hidden. Thereby, the flow resistance and thus the extent of the pressure medium supply of the pressure chambers 12, 13 can be adjusted.

To prevent pressure fluid from the Steignuten 114a, 114b, 114p can flow directly into the second bore 108 and to prevent leakage currents between the Steignuten 114a, 114b, 114p, in particular at the interface between the surrounding structures 109, 110 is between the valve housing 105 and the axial stop 111, a sealing element 124 is provided. The sealing element 124 is designed in the illustrated embodiment as an elastically deformable sealing ring and preferably made of fluorine rubber or acrylonitrile-butadiene rubber. Advantageously, the sealing element 124 is arranged on the outer diameter-reduced region 112 of the valve housing 105. During assembly of the control valve 101 in the valve seat 106, the seal member 124 is positioned in the outer diameter reduced portion 112 of the valve housing 105. Subsequently, the valve housing 105 is inserted and secured in the valve receptacle 106. As a result of the arrangement on the region 112 reduced in the outer diameter, the sealing element 124 is centered and guided during the assembly process, as a result of which incorrect assembly can be reliably avoided. By using an elastically deformable sealing element 124 axial tolerances can be compensated.

The sealing element 124 is pressed by the valve housing 105 in the installed state against the axial stop 111. In this case, it is surrounded by the axial stop 111 and the step of the outer diameter reduced portion 112 of the valve housing 105 U-shaped. As a result of the force effect, the sealing element 124 deforms elastically and is therefore pressed against the inner lateral surface of the valve receptacle 106 due to the U-shaped clamping. This ensures an optimal and early sealing effect in the axial direction.

Advantageously, the sealing element 124 is arranged such that it comes to rest on the inner surface of the valve receptacle 106 at the interface between the two surrounding structures 109, 110. As a result, any existing columns are closed at this interface and ensures the sealing effect in the circumferential direction.

By forming the second bore 108 with a smaller inner diameter compared to the first bore 107, an axial stop 111 is formed which limits the insertion depth of the control valve 101 into the valve receptacle 106 and acts in conjunction with the sealing element 124 as a sealing surface. The control valve 101 engages only with its reduced in outer diameter portion 112 in the second bore 108 a. Since this area 112 in conjunction with the inner lateral surface of the second bore 108 does not assume a sealing function, its outer diameter may be smaller than the inner diameter of the second bore 108, which makes the system less susceptible to tolerances

Furthermore, further seals 125 are provided at the interface between the control housing 103 and the valve housing 105 or the valve housing 105 and the first bore 107, which prevent leakage currents in the direction of the actuator 102 and thus into the engine compartment.

Figures 5 and 6 show a second embodiment of the invention. The second embodiment is largely identical to the first embodiment, which is shown in Figures 3 and 4. In contrast to the first embodiment, the second bore 108 is step-shaped. In this case, the inner diameter of a first region 126, which adjoins directly to the first bore 107, is made larger than the inner diameter of the first bore 107. Furthermore, the inner diameter of a second region 127 adjoining the first region 126 is smaller than the inner diameter of the first bore 107. An axial stop 111 is thus formed at the transition from the first region 126 to the second region 127. The valve housing 105 passes through the first bore 107 of the first Surrounding structure 109 and engages the second surrounding structure 110. Due to the larger inner diameter of the first portion 126 of the second bore 108, this is possible even with slight displacement of the holes 107, 108 to each other. In this embodiment, the transition region 128 of the valve housing 105 to the diameter-reduced region 112 is not stepped, as in the first embodiment, but at least partially conical. The sealing element 124 is designed as a sealing ring and arranged in the transition region 128, wherein the shape of the sealing element 124 of the shape of the transition region 128, in particular its conicity, 127 is adjusted. The inner lateral surface 133 of the sealing element 124 thus has a first conical region 129, wherein the inner diameter in the axial direction continuously decreases starting from the end side until it corresponds to the outer diameter of the outer diameter reduced region 112. On an outer circumferential surface 134 of the sealing element 124, a second conical region 131 is formed, wherein this is formed on the annular edge 130 offset in the axial direction to the first conical region 129. The outer diameter of the sealing element 124 increases starting from the end face in the axial direction until the maximum outer diameter of the sealing element 124 is reached.

The axial length of the first region 126, the outer diameter reduced portion 112 and the sealing member 124 is designed such that the sealing element 124 in the region of the interface between the first surrounding structure 109 and the second surrounding structure 110 both at the first bore 107 and at the second bore 108 is present.

The attached in the outer surface of the valve housing 105 conical region causes the sealing element 124 pressure-tight against the lateral surface of the first bore 107 and the lateral surface of the first portion 126 of the second bore 108. Due to the shape of the sealing element 124, a cavity 132 is formed between the second bore 108 and the sealing element 124. This allows the compensation of any axial play occurring during assembly. The valve housing 105 may in this case displace material of the sealing element 124 into the cavity 132, whereby the control valve 101 can be further inserted into the valve seat 106 in the axial direction. This cavity 132 makes it possible to compensate axial tolerances to a greater extent than is made possible by the sealing element 124 shown in the first embodiment. Of course, the sealing element 124 of the second embodiment can also be used in the valve receptacle 106 of the first embodiment and vice versa. Furthermore, both sealing elements 124 and the control valve 101 in a single, stepped bore, which serves as a valve receptacle 106, find use. Also provided is the use of the sealing element 124 and the control valve 101 in a bore which is bounded by an annular, extending in the radial direction wall

FIGS. 7 and 8 show a sealing element 124 according to the invention in the form of a sealing ring. Depending on an annular edge 130 of the inner 133 and the outer lateral surface 134 of the sealing element 124 is conical. The taper is formed such that the partial cross-sectional shape of the seal member 124 is achieved by mate rialabt of two edges of a rectangular surface. That the first conical region 129 on the inner lateral surface 133 is funnel-like, and the second conical region 131 on the outer lateral surface 134 has a truncated cone shape.

Furthermore, the sealing element 124 is made of an elastomer. In this case, as a material, for example, a fluorine rubber or an acrylonitrile-butadiene rubber can be used.

reference numeral

1 device

2 stators

3 rotor

4 drive wheel

5 recesses

6 side wall

7 first side cover

8 second side cover

9 connecting element

10 wing groove

11 wings

12 first pressure chamber

13 second pressure chamber

14 groove base

15 leaf spring element

16 first pressure medium line

17 second pressure medium line

18 control valve

19 pressure medium pump

20 tank

21 arrow

22 central bore

23 formations

24 locking element

25 axial bore

26 pistons

27 first spring

28 venting element

29 scenery

30 recess 31 pressure medium circuit

32 adjusting device

33 second spring

A first work connection

B second work connection

P inlet connection

T drain connection

101 control valve

102 adjusting device

103 control housing

104 control piston

105 valve housing

106 valve seat

107 first hole

108 second hole

109 first surrounding construction

110 second environment construction

111 axial stop

112 outer diameter reduced area

113 pressure medium channel

114a first Steignut

114b Second Steignut

114p third Steignut

115a first radial opening

115b second radial opening

115p third radial opening

116a first annular groove

116b second annular groove

116p third annular groove

117a first opening 117b second opening

117p third opening

119 push rod

120 first spring element 121 control section

122 fourth annular groove

123 fourth openings

124 sealing element

125 seal 126 first area

127 second area

128 transition area

129 first conical area

130 ring edge 131 second conical area

132 cavity

133 Inner circumferential surface

134 outer jacket surface

Claims

claims

1. sealing element (124) in the form of a sealing ring for sealing an axial end face of a control valve (101) of a device (1) for changing the timing of gas exchange valves with an inner circumferential surface (133) and an outer circumferential surface (134) characterized in that the inner (133) and the outer circumferential surface (134) is provided at each one of the annular edges (130) with a conical portion (129, 131).

Second sealing element (124) according to claim 1, characterized in that the two conical regions (129, 131) are formed on mutually offset in the axial direction annular edges (130) of the sealing element (124).

3. Control valve (101) for controlling the inflow and outflow of pressure medium to a device (1) for changing the control times of an internal combustion engine having a substantially cylindrical valve housing (105), at the pressure medium connections (A, B, P, T) are formed and - with an inside of the valve housing (105) arranged, axially displaceable control piston (104),

- Wherein depending on the position of the control piston (104) a connection between the various pressure medium connections (A, B, P, T) is producible or separable, - wherein the valve housing (105) is arranged within a valve receptacle (106) and,

- wherein the insertion depth of the valve housing (105) in the valve receptacle (106) by an in the valve receptacle (106) formed axial stop (111) is limited, characterized in that - wherein the axial stop (111) is formed as a circular or annular wall . - Which extends starting from an inner circumferential surface of the valve receptacle (106) radially inwardly

- And that between the valve housing (105) and the axial stop (111) of the valve seat (106), a sealing element (124) is arranged.

4. control valve (101) according to claim 3, characterized in that the axial stop side end face of the valve housing (105) is formed with a reduced outer diameter area (112), wherein the sealing element (124) at least partially in the outer diameter reduced area (112) is arranged.

5. control valve (101) according to claim 3, characterized in that the

Sealing element (124) is designed as a sealing ring with an outer (134) and an inner circumferential surface (133).

6. control valve (101) according to claim 3, characterized in that the sealing element (124) consists of an elastomer.

7. control valve (101) according to claim 12, characterized in that the elastomer is a fluorine rubber or an acrylonitrile-butadiene rubber.

8. Control valve (101) according to claim 3, characterized in that the

Valve receptacle (106) is composed of a first and a second bore (107, 108), wherein the bores (107, 108) formed in different Lich surrounding constructions (109, 110), at least approximately coaxially arranged and subsequently executed.

9. control valve (101) according to claim 5, characterized in that the

Axial stop (111) at the interface of the two surrounding structures (109, 110) is formed.

10. control valve (101) according to claim 5, characterized in that the

Axial stop (111) in the insertion direction of the control valve (101) second bore (108) is formed.

11. Control valve (101) according to any one of claims 6 or 7, characterized in that the axial stop (111) is arranged and the sealing element (124) is formed such that the sealing element (124) at the interface of the two surrounding structures (109, 110) bears against the valve receptacle (106).

12. control valve (101) according to claim 5, characterized in that the transition region (128) of the valve housing (105) to the diameter-reduced portion (112) is at least partially conical and the sealing element (124) on the inner lateral surface (133) with a first is provided conical portion (129), wherein the transition region (128) of the valve housing (105) is adapted.

13. Control valve (101) according to claim 5, characterized in that the outer circumferential surface (134) of the sealing element (124) is provided at the axial end (111) abutting end face with a second conical region (131), so that an annular Cavity (132) between the sealing element (124) and the axial stop (111) is formed.