DE10341698A1 - Valve drive for a gas exchange valve - Google Patents

Abstract

The invention relates to a valve drive for a gas exchange valve (11) in a motor or working machine, with a magnetic rotor (12), which is located with a preferably hollow cylindrical rotor section located away from the gas exchange valve (11) within a rotor section with a current coil (23). provided stator (1) extends longitudinally so that an end of the rotor (12) protruding from the stator (1) actuates the gas exchange valve (11) when the current coil (23) is excited. The rotor (12) forms with the stand (1) an independently manageable, preferably functionally testable, assembly which is detachably connected to the gas exchange valve (11).

Description

The The invention relates to a valve drive for a gas exchange valve the preamble of claim 1.

A whole series of valve actuators of the specified type are known from the patent literature. For example, on the DE 101 25 767 C1 directed.

rationale this valve drive already known from the patent is that a rotor rigidly connected to the gas exchange valve along the common axis in the Magnetic field of a stator moves.

Around To generate economically high enough forces on the rotor will be accordingly strong magnetic fields are required in the air gap between the stator and the rotor. For this have to et al the air gaps in the magnetic circuit should be as small as possible and suitable Current coils on the stand to be ordered.

Furthermore must be out of the stand and the runner existing actuator in the existing, relatively small installation spaces, for. B. fit into a cylinder head of a motor vehicle internal combustion engine, which is why Current coils and the active air gap surfaces are not built to any size can be. The magnetic losses must be kept small in the magnetic circuit. Moreover, are also straight Current and voltage are limited in the vehicle electrical system.

at the complex geometries on a cylinder head of an internal combustion engine are very significant geometrical tolerances between the individual To comply with functional elements, especially between the rotor and the stand of the valve drive, jamming or too large air gaps to prevent.

moreover to lead asymmetrical magnetic fields in the air gap on the rotor to considerable transverse forces reinforce yourself and too big frictional forces, Loss of energy and even lead to jamming of the rotor already mentioned.

There especially with internal combustion engines in the warm-up and cool-down phase with considerable temperature differences on all Engine components and thus thermally induced changes in geometry (an Components made of materials with different thermal expansion and very different temperatures) must be expected, especially in Valve train the air gaps and games sufficient for thermal reasons held large become.

On Accelerations up to 100 times occur in the gas exchange valves the acceleration due to gravity. These lead to excessive component play and in the air gap of the magnetic circuit to undesirable noise, asymmetrical Forces and Wear in Valve drive.

Also are wear, abrasion and dirt particles in an internal combustion engine available, some of which are also magnetic. These particles can become also accumulate in the magnetic gaps of the actuator and jam of the valve drive.

On considerable manufacturing problem poses both in a working as well as the connection of a gas exchange valve with the engine the valve actuator. As a result of the local and functional Conditions, namely must an independent one verifiability, Assembly and disassembly of the gas exchange valve and the valve train guaranteed in the cylinder head his.

Therefore it is the object of the present invention to provide a valve drive to improve the type mentioned in such a way that the aforementioned requirements fulfilled and the disadvantages shown are avoided.

This Task is according to the invention for one Valve drive of the type specified by the characteristic features of claim 1 solved.

Further Features, advantages and possible uses of the invention go in the following from the subclaims and the description of an embodiment based on several drawings.

It demonstrate:

1 3 shows a cross section through a cylinder head in which a valve drive with a coupling element according to the invention is arranged,

2 a schematic view of the in 1 valve drive according to the invention shown in section without coupling element,

3 the valve drive 2 in the area of the horizontal cutting plane BB,

4a the valve drive 2 in the area of the horizontal section plane AA,

4b a spatial representation of the runner with external guide elements,

4c a spatial representation of the runner with internal guide elements,

5a - e several variants for the coupling element for the detachable arrangement of the gas exchange valve on the valve drive.

The 1 shows the arrangement of a valve drive in a cylinder head 2 an internal combustion engine for the purpose of actuating the gas exchange valve arranged on the inlet side 11 , The cylinder head shown in cross section 2 has a first valve receiving bore 3 for guiding and sealing the gas exchange valve on the inlet side 11 and a second valve receiving bore 3 for a gas exchange valve on the outlet side 4 on, which are both arranged at a V-angle to each other. The gas exchange valves 4 . 11 are designed as poppet valves with their valve seats in the inlet and outlet channels 5 . 6 used valve seat rings 16 are facing concentrically. In this example, the inlet and outlet channels are 5 . 6 in cross-flow technology and the gas exchange valves 4 . 11 operated in a hanging arrangement according to the OHC principle (Over Head Camshaft).

Above the gas exchange valve on the outlet side 4 Accordingly, there is a conventional valve drive in the form of a camshaft 17 whose cams over a tappet 18 on the valve stem 7 of the gas exchange valve on the outlet side 4 acts.

In contrast to this, the valve drive is located above the gas exchange valve on the inlet side 11 an electromagnetic actuator in its stand 1 an axially movable rotor 12 is arranged via a coupling element 22 with the valve stem 7 of the gas exchange valve on the inlet side 11 is detachably connected. This valve drive, designed as a linear motor, ensures variable charge change, depending on the control of a current coil 23 in the stand 1 the valve opening time, the valve lift and the valve opening duration of the intake-side gas exchange valve 11 are freely adjustable.

Of course you can If desired or required, the conventional one presented for the exhaust valve Valve train through the for the actuator described in the inlet valve are replaced.

The invention provides that the runner 12 with the stand 1 an independently manageable, preferably functional pre-testable assembly that forms with the gas exchange valve 11 is detachably connected. This is between the runner 12 and the gas exchange valve 11 arranged coupling element 22 required a non-positive and / or positive connection between the runner 12 and the gas exchange valve 11 manufactures.

How out 1 emerges is the stand 1 with the runner 12 and the runner 12 attached coupling element 22 opposite the gas exchange valve 11 in the cylinder head 2 aligned and fixed coaxially. To the protrusion of the valve drive on the cylinder head 2 To keep it as low as possible, the cylinder head above the gas exchange valve on the intake side 11 a hollow 24 on which of the stands 1 is attached. Furthermore, for space-saving integration of the coupling element 22 between the valve mounting hole 3 (Valve stem guide) of the gas exchange valve on the inlet side 11 and the hollow 24 a stepped bore 25 in the cylinder head 2 intended. Between the coupling element 22 and the bottom of the stepped bore 25 there is an auxiliary spring 26 to in the event of a power coil failure 23 the gas exchange valve to avoid piston contact 11 to be able to safely close again. The stand 1 and the cam-side valve drive are from one on the cylinder head 2 attached cylinder head cover 27 covered.

The further details of the valve drive designed as a linear motor are described below with reference to 2 - 5 explained.

The 2 shows the in 1 presented valve drive according to the invention, consisting of a magnetic rotor 12 with its from the intake gas exchange valve 11 distant, preferably hollow cylindrical rotor section within one with the current coil 23 provided stand 1 longitudinally movable, one below from the stand 1 protruding end of the runner 12 when the current coil is excited 23 about the not shown Kop pelelement 22 the gas exchange valve 11 actuated. The stand 1 consists of a magnetic material with a radially inner area and a radially outer area. The stator hole is located in the inner area 14 and the stator core 15 by an internal current coil 23 is enclosed. In parallel, there is a further external current coil 23 in the outer area of the stator 1 , Both current coils 23 are inside a stator coil chamber 28 radially spaced from each other such that between the two current coils 23 an essentially hollow cylindrical rotor section is arranged to be axially movable. This rotor section is provided with a plurality of magnetic rings stacked concentrically one above the other 29 provided an alternating magnetic orientation exhibit. The magnetic rings 29 are in a radial air gap between an internal and external tooth area 30 of the stand 1 arranged by two in alignment with each other, the magnetic rings 29 facing circular cylindrical teeth. Regardless of the number of teeth, the chosen arrangement ensures that the magnetic rings 29 Always align with the assigned teeth with the same magnetic orientation.

Because the magnetic rings 29 it is difficult to magnetize with different polarity instead of the magnetic rings 29 the use of individual magnetic segments that are easy to manufacture or magnetize and that are in a row in a ring on the rotor 12 be attached. The runner 12 is preferably made of a plastic or a composite material, for which a combination of plastic and non-magnetic metal is particularly suitable.

The structure of the stand described above 1 is with the current coils 23 Available in duplex construction and preferably in tandem, so that two identical, with their tooth areas 30 stands facing each other 1 are stacked in alignment. Between the two stands 1 there is a plate-shaped, non-magnetic spacer 10 , which is an unwanted mutual magnetic influence of both stands 1 prevented. The lower, first end region of the one stator facing the valve side 1 differs only from the stand arranged above 1 through its vertical opening (bushings 8th ) in the Grundjoch 9 through which the runner 12 with its magnetic rings in the stator coil chambers 28 extends. This along the section line BB in the lower area of the stand 1 The level shown below is based on the 3 explained in more detail.

The 3 shows a plan view of the stand 1 along the in 2 outlined section line BB, from which the formation of the opening as segment-shaped openings in the first end region of the stand 1 emerges from the gas exchange valve 11 turned towards. In this first end of the stand 1 the previously mentioned openings are functional as three bushings 8th realized, through which three on the runner 12 arranged runner bars 19 extend. The implementations 8th and the runways 19 are at a uniform angular distance over the circumference of the stand 1 distributed that arranged for the runways 19 intended implementations 8th through several connecting bars that conduct the magnetic flux 20 of the stand 1 are spaced from each other. The cross-sectional area of each connecting bridge 20 is meaningfully much larger than the opening cross section of each bushing 8th chosen in order to achieve a gain in magnetically conductive stand material compared to the prior art, or to achieve the required opening in the base yoke 9 to keep the resulting magnetic losses as low as possible.

The stand 1 has an essentially oval shape in the present exemplary embodiment, which is shown by the representation of the stator 1 in plan view after 3 becomes particularly clear. The two diametrically arranged, on the outside area of the stand 1 arranged current coils 23 are in as coil winding packages 3 equally well recognizable, through which the (already out 2 ) clearly recognizable, vertically directed connection yoke 31 to the horizontal legs of the stand 1 which extends the tooth area mentioned above 30 exhibit.

Referring to section line AA after 2 should now be based on the 4a another top view of a profile section of the stand 1 are explained in more detail.

The 4a shows the above the stand described above 1 arranged further stands 1 that removed from the gas exchange valve 11 and removed from the first end portion of the lower stand 1 is arranged. This other stand 1 has several guide elements 13a . 13b . 13c on, which are evenly distributed over the outer or the inner circumference of the runner 12 (see an example of one of three guide elements 13d ) in the stand 1 are arranged and at least in sections on the outer or inner circumference of the rotor 12 are attached. The three leadership elements 13a . 13b . 13c are shown in three grooves 32 of the stand 1 guided, the groove depth in the grooves 32 is chosen to be considerably greater than the immersion depth of the guide elements 13a . 13b . 13c in the grooves 32 in the unheated state. This ensures that due to the thermal expansion of the rotor 12 Always a jam-free running game of the guide elements 13a - c in the grooves 32 is observed.

The three leadership elements 13a . 13b . 13c are at a uniform angular distance preferably along the outer circumference (or possibly also along the inner circumference, see for example one of three guide elements 13d on the inside of the stand 33 ) of the runner 12 distributed, why in the wall of the stand 1 groove 32 are provided. This ensures precise, jam-free guidance of the gas exchange valve 11 distal end of the runner 12 in the stand 1 reached. Further goes out 4a the inside of the stand, which is guided without play 1 on the inside of the stand 33 attached internal current coil 23 as well as that in the stand Area 33 arranged stator core 15 from a stator hole 14 is penetrated in the middle.

The 4b illustrates the tubular structure of the rotor in a spatial representation 12 with the three guide elements molded onto the outer circumference of the rotor 13a . 13b . 13c that either extend partially over the entire runner height. At the bottom of the runner 12 are also the runways 19 to recognize who is according to 3 in the bushings 8th in the Grundjoch 9 of the stand 1 extend.

The 4c illustrates the tubular structure of the rotor in a spatial representation 12 with the three guide elements molded onto the circumference of the runner 13d that in the grooves 32 of the stand area 33 intervene which is outside the current coil 23 located.

Referring to that in 1 coupling element shown 22 are in the 5a - 5e shown several embodiments, which are described in more detail below.

It shows the 5a a first embodiment of the coupling element 22 in the form of a clamping ring 21 , the inside of the valve stem 7 of the gas exchange valve 11 embraces. The outside of the clamp ring 21 however, is from the coupling element 22 added what the coupling element 22 with a hollow cylinder and an annular groove located therein 34 or is provided with a pipe section designed as a gripper, in which the clamping ring 21 is fixed.

The 5b shows in modification of the clamping ring 21 to 5a the engagement of a collar provided with a collar 21 into a groove in the valve stem 7 ,

The 5c discloses a pin 35 in a pocket opening in the valve stem 7 is pressed in, the end of the clamping pin 35 with a bunch 36 is provided by the housing of the coupling element 22 is encompassed.

Instead of a clamping pin 35 is in 5d the use of a ferrule 37 suggested that over a covenant 36 with the housing of the coupling element 22 is engaged.

Finally, in the 5e the ferrule 37 to 5d around an adjustment device 38 supplemented by the clamping sleeve 37 an adjusting screw in a threaded blind hole of the valve stem 7 protrudes so that by turning the adjusting screw of the valve stem 7 more or less deep into the ferrule 37 can be moved.

The in the 5a - 5e The connection technologies presented can of course be combined in a variety of ways with non-positive, positive and / or integral connection variants if desired or required.

• 1. Eine leicht füg- und trennbare Funktionsgruppen, bestehend aus dem Ständer 1 mit Läufer 12, dem Koppelelement 22 und dem Gaswechselventil 11.
• 2. Anordnung von über den Umfang des Grundjochs 9 (erster Endbereich des Ständers 1) verteilten Durchführungen 8. Damit werden die Verluste im Magnetkreis um Potenzen reduziert, da der Magnetkreis in diesem Bereich nicht wie bisher nur über einen großen ringförmig umlaufenden Luftspalt geschlossen wird, sondern über die magnetisch gut leitenden Stege 20.
• 3. Einfacher Ausgleich der Fertigungstoleranzen zwischen Ständer 1, Läufer 12, Zylinderkopf 2 und Gaswechselventil 11 in Richtung der Längsachse des Ventilantriebs und des Gaswechselventils 11 durch eine verblüffend einfache Ankoppelung und Ventileinstellung, indem unter Bezug auf die Dar stellung nach 1 eine Ventilschließkraft F das Gaswechselventil 11 auf dem Ventilsitzring 16 hält und ein durch die Ständerbohrung 14 auf das Koppelelement 22 wirksamer Einstellstift 39 (bei im Zylinderkopf 2 montiertem Ständer 1) über das am Läufer 12 ausgebildete Koppelelement 22 eine Kraft erzeugt, die den Läufer 12 in der genauen Position zum Ständer 1 positioniert. Eine alternative Einstellung mittels einer Einstellschraube ist bereits aus 5e bekannt.
• 4. Einfache, toleranzausgleichende Wirkung durch die zwischen dem Ventilantrieb und dem Gaswechselventil 11 angeordneten Hilfsfeder 26.
• 5. Eine von thermisch induzierten Geometrieveränderungen unabhängige Führung des Läufers 12, wobei Durchmesserveränderungen zwischen Läufer 12 und Ständer 1 keinen Einfluß auf die Führung haben. Durch die hierzu vorgeschlagene Verwendung von Führungselementen 13a–c wird der Läufer 12 auch in einem kritischen Luftspaltbereich sicher geführt und gegen die dort wirkenden hohen magnetischen Querkräfte sowie gegen die Querbeschleunigungskräfte abgestützt. Die hierzu verwendete Anzahl der Führungselementen kann zwischen zwei und einem Vielfachen variieren.
• 6. Große zulässige Fertigungstoleranzen der Einzelteile und damit kostengünstige Fertigung des Ventilantriebs.
• 7. Einfache Montage aller Teile des Ventilantriebs im Zylinderkopf 2.
• 8. Einfacher Service im Werkstattbetrieb.
• 9. Die Hilfsfeder 26 verhindert, daß der Ventilteller den Kolben des Verbrennungsmotors berührt und dabei zerstört wird.

The valve drive proposed according to the invention is characterized in summary by the following features:

• 1. An easily joinable and separable functional group consisting of the stand 1 with runner 12 , the coupling element 22 and the gas exchange valve 11 ,
• 2. Arrangement of the circumference of the basic yoke 9 (first end of the stand 1 ) distributed implementations 8th , This reduces the losses in the magnetic circuit by potencies, since the magnetic circuit in this area is not closed, as was previously the case, only via a large, annular air gap, but via the magnetically well-conductive webs 20 ,
• 3. Easy compensation of manufacturing tolerances between stands 1 , Runner 12 , Cylinder head 2 and gas exchange valve 11 in the direction of the longitudinal axis of the valve drive and the gas exchange valve 11 through an astonishingly simple coupling and valve adjustment, by referring to the illustration 1 a valve closing force F the gas exchange valve 11 on the valve seat ring 16 stops and one through the stator hole 14 on the coupling element 22 effective adjustment pin 39 (at in the cylinder head 2 assembled stand 1 ) about that on the runner 12 trained coupling element 22 a force that generates the runner 12 in the exact position to the stand 1 positioned. An alternative setting using an adjusting screw is already out 5e known.
• 4. Simple, tolerance-compensating effect due to the between the valve actuator and the gas exchange valve 11 arranged auxiliary spring 26 ,
• 5. Guiding the rotor independently of thermally induced changes in geometry 12 , diameter changes between runners 12 and stand 1 have no influence on the leadership. Due to the proposed use of guide elements 13a - c becomes the runner 12 also safely guided in a critical air gap area and supported against the high transverse magnetic forces acting there as well as against the lateral acceleration forces. The number of guide elements used for this can vary between two and a multiple.
• 6. Large permissible manufacturing tolerances of the individual parts and thus inexpensive manufacture of the valve drive.
• 7. Easy assembly of all parts of the valve drive in the cylinder head 2 ,
• 8. Simple service in the workshop.
• 9. The auxiliary spring 26 prevents the valve plate touches the piston of the internal combustion engine and is destroyed.

• – Wirtschaftliche Fertigungstoleranzen
• – Wirtschaftliche Montage und automatische Justierung des Ventilantriebs
• – Geringe Verluste im Magnetkreis
• – Hohen Wirkungsgrad, da optimal einstellbar und geringe Reibkräfte
• – Thermisch stabil auch in der Hochlauf- und Abkühlphase des Motors
• – Einfacher Werkstattservice
• – Nachstellbar bei starkem Ventilverschleiß

The proposed invention thus ensures:

• - Economic manufacturing tolerances
• - Economical assembly and automatic adjustment of the valve drive
• - Low losses in the magnetic circuit
• - High efficiency, as optimally adjustable and low friction forces
• - Thermally stable even in the run-up and cooling phase of the engine
• - Simple workshop service
• - Adjustable in the event of heavy valve wear

Finally, it should be noted that the proposed invention is not limited to the exemplary embodiments explained, but offers a wide range of possible uses, regardless of whether the magnetic rotor 12 Is part of a linear motor, a magnetic drive in the form of one or more serially arranged electromagnets or a piezo drive.

1

stand

2

cylinder head

3

Valve accommodating bore

4

Gas exchange valve

5

inlet channel

6

exhaust port

7

valve stem

8th

execution

9

basic yoke

10

spacer

11

Gas exchange valve

12

runner

13a

guide element

13b

guide element

13c

guide element

14

stator bore

15

stator core

16

Valve seat ring

17

camshaft

18

tappets

19

runners web

20

connecting web

21

clamping ring

22

coupling element

23

current coil

24

trough

25

stepped bore

26

auxiliary spring

27

cover

28

Current coil chamber

29

magnetic ring

30

posterior region

31

connecting yoke

32

groove

33

Stand Interior

34

ring groove

35

clamping pin

36

Federation

37

collet

38

adjustment

39

adjusting pin

Claims (8)

Valve drive for a gas exchange valve in an engine or working machine, with a magnetic rotor, which extends with a preferably hollow cylindrical rotor section away from the gas exchange valve within a stator provided with a current coil, so that an end of the rotor protruding from the stator is excited when excited the current coil actuates the gas exchange valve, characterized in that the rotor ( 12 ) with the stand ( 1 ) forms an independently manageable, preferably functionally testable assembly, which, together with the gas exchange valve ( 11 ) is releasably connected. Valve drive according to claim 1, characterized in that in a first region of the stator ( 1 ), the gas exchange valve ( 11 ), several implementations ( 8th ) are provided, through which several on the runner ( 12 ) arranged runways ( 19 ) extend. Valve drive according to claim 2, characterized in that the bushings ( 8th ) and the runways ( 19 ) at an even angular distance over the circumference of the stand ( 1 ) are distributed. Valve drive according to claim 3, characterized in that the for the rotor webs ( 19 ) intended implementations ( 8th ) by several connecting bars that conduct the magnetic flux ( 20 ) of the stand ( 1 ) are spaced from one another, the cross-sectional area of each connecting web ( 20 ) much larger than the opening cross section of each bushing ( 8th ) is. Valve drive according to claim 2, characterized in that a second region of the stator ( 1 ), which turns away from the first area of the stand ( 1 ) is arranged, with several on the outer or inner circumference of the rotor ( 12 ) attached guide elements ( 13a . 13b . 13c . 13d ) is engaged, for which purpose the guide elements ( 13a . 13b . 13c . 13d ) in several grooves ( 32 ) of the stand ( 1 ) are movably arranged, which are distributed radially over the outer or inner circumference of the stand ( 1 ) are arranged. Valve drive according to claim 5, characterized ge indicates that the guide elements ( 13a . 13b . 13c . 13d ) at an even angular distance along the inner or outer circumference of the stand ( 1 ) in the grooves ( 32 ) of the stand ( 1 ) immerse, with the groove depth chosen to be greater than the immersion depth of the guide elements during operation of the rotor to compensate for manufacturing and thermal expansion tolerances of the components ( 12 ). Valve drive according to claim 1, characterized in that between the rotor ( 12 ) and the gas exchange valve ( 11 ) a coupling element ( 22 ) is arranged that a non-positive and / or positive connection between the rotor ( 12 ) and the gas exchange valve ( 11 ) produces. Valve drive according to claim 7, characterized in that the coupling element ( 22 ) is provided with a locking and / or clamping mechanism, which is preferably used as a locking hook or clamping ring ( 21 ) is executed.