EP2539552B1 - Device for variably adjusting the control times of gas exchange valves of an internal combustion engine - Google Patents

Abstract

A device (11) for variably adjusting the control times of gas exchange valves (9, 10) of an internal combustion engine (1), including a drive element (13), an output element (14), and at least one lateral cover (15). The drive element (13) can be brought into driving connection with a crankshaft (2) of the internal combustion engine (1), and the output element (14) can be brought into driving connection with a camshaft (6, 7) of the internal combustion engine (1) and is arranged in a pivotable manner with respect to the drive element (13). The lateral cover (14) lies on an axial lateral surface of the output element (14) or of the drive element (13) and is connected to the drive element (13) or to the output element (14) in a rotationally fixed manner. A spring element (25) lies on the lateral cover face that faces away from the drive and output element (13, 14), and the lateral cover (15) has a disk-shaped portion (23) from which multiple fixing elements (24) protrude in the axial direction, said elements lying on the lateral cover (15) face that faces away from the drive element (13).

Description

Field of the invention

The invention relates to a device for the variable adjustment of the timing of gas exchange valves of an internal combustion engine with a drive element, an output element and at least one side cover, wherein the drive element can be brought into drive connection with a crankshaft of the internal combustion engine, wherein the output element can be brought into drive connection with a camshaft of the internal combustion engine and is arranged pivotably to the drive element, wherein the side cover is arranged on an axial side surface of the output element or the drive element and rotatably connected to the drive element or the driven element, wherein on the side facing away from the input and the driven element side of the side cover, a spring element is arranged and wherein the side cover has a disc-shaped portion from which protrude a plurality of fastening elements in the axial direction, which angeo on the side facing away from the drive element of the side cover rdnet are.

Background of the invention

In modern internal combustion engines devices for variable adjustment of the timing of gas exchange valves are used to adjust the phase relation between a crankshaft and a camshaft in a defined angular range, between a maximum early and a maximum late position variable. The device is integrated in a drive train via which torque is transmitted from the crankshaft to the camshaft. This powertrain can be used, for example, as belt, chain or gear drive to be realized. In addition, the device is non-rotatably connected to a camshaft and, for example, have one or more pressure chambers, by means of which the phase relation between the crankshaft and the camshaft can be selectively changed by pressure medium.

Such a device is for example from the DE 10 2008 017 688 A1 known. The device has a drive element, an output element and two side covers, wherein the drive element is in driving connection with a crankshaft and the output element is non-rotatably attached to a camshaft. In this case, the output element is arranged in a defined angular interval pivotally to the drive element. The drive element, the output element and the side cover define a plurality of pressure chambers, which form a hydraulic actuator by means of which the phase angle between the output element and the drive element can be variably adjusted. The side covers are arranged on the axial side surfaces of the output element and the drive element and rotatably connected by screws with the drive element. The screws pass through the first side cover and the drive element and engage in each case a clamping nut, which are manufactured separately from the side cover and inextricably linked thereto.

From the DE 197 08 661 B4 Another device is known in which the clamping nuts are not firmly connected to the side cover.

From the DE 10 2005 024 241 A1 Another device is known, wherein the fastening element are integrally formed with the side cover. The fasteners are designed as cylindrical collars, which are provided with an internal thread and protrude in the axial direction of the side cover.

From the DE 100 07 200 A1 Another device is known which has a spring element, which on the one hand to the output element and on the other engages the drive element. In this case, a screw, by means of which a side cover is fastened to the drive element, projects out of the device. The spring element has a hook which is hooked into this protruding area.

Object of the invention

The present invention has for its object to propose a device with increased life and reliability.

Summary of the invention

The object is achieved in that the disc-shaped portion on the spring element facing side surface has at least one bulge, which faces at least one spring coil of the spring element in the axial direction of the device.

The device has a drive element and an output element, wherein the drive element is driven by a crankshaft of the internal combustion engine and the output element drives a camshaft of the internal combustion engine. The drive element can be in drive connection with the crankshaft, for example, by means of a traction mechanism or gear drive. The output member may be rotatably connected to the camshaft, for example. Furthermore, an actuator, for example a hydraulic actuator with at least two counteracting pressure chambers, provided by means of which the output element can be pivoted in a defined angular range relative to the drive element. Thus, a phase relation between the output element and the drive element is variably adjustable. On an axial side surface of the drive element and / or the output element, a side cover is provided which is rotatably connected to one of these components. In this case, the side cover on a disc-shaped portion, optionally with a central opening, which seals, for example, the pressure chambers in the axial direction. From the output element or the drive element facing away from the axial side surface of the side cover fasteners protrude in the axial direction. These may be, for example, screw heads of screws or clamping nuts into which the screws engage. By means of the fastening elements, the connection between the side cover and the output element or the drive element can be produced. In the case of clamping nuts, these can be firmly connected to the disc-shaped section before assembly of the side cover or be present as a separate component. Likewise conceivable are embodiments in which the fastening elements are formed integrally with the disk-shaped section, for example as cylindrical collars, which are provided with an internal thread.

The disk-shaped portion is preceded by a spring element is provided which, for example, as a helical spring, in particular as a spiral spring, is formed, and on the one hand acts on the output element and on the other hand on the drive element. By means of the spring element, the output element is acted upon relative to the drive element with a torque which can be used, for example, to compensate for friction losses or to achieve a base position with insufficient pressure medium.

If the spring element is excited to axial vibrations during operation of the internal combustion engine, there is a risk that the spring element or a turn of the spring element dips into the region between the fastening elements and jammed there, whereby the function of the spring element is disabled or the spring element is damaged ,

To prevent this, the disc-shaped section on the side facing the spring element at least one bulge, which faces at least one spring coil of the spring element in the axial direction of the device. The bulge serves as a stop for the spring element. If the spring element is excited to axial vibrations, then it is true this on the spacer, whereby the vibration amplitudes are reduced. Thus, the vibration loads acting on the spring element decrease. Furthermore, the vibrations are damped. In addition, the rigidity of the disk-shaped portion is increased by the bulges.

Advantageously, the extent of the bulge in the radial direction of the disc-shaped portion is formed such that each spring coil of the spring element of the bulge facing in the axial direction and thus each spring coil undergoes the desired damping.

In addition, it can be provided that the bulge limits an axial movement of the spring coil such that it can not dip into a region radially within the fastening elements. Thus, it is prevented that the spring coil between the fasteners jammed and so off the function of the spring element or the spring element is damaged.

In an advantageous embodiment of the invention can be provided that the bulge is formed integrally with the disc-shaped portion.

It is conceivable, for example, that the disc-shaped section on the side facing away from the spring element has a recess in the region of the bulge. The bulge is thus formed groove-shaped on the disc-shaped portion.

In this case, it can be provided that the device has pressure chambers which are separated by vanes and projections, that the depression is arranged in the region of the pressure chambers, vanes and projections and that components of the group of vanes and projections are pivotable relative to the depression, wherein the recess is arranged outside the pivoting range of the pivotable components. Thus, a short circuit between two adjacent pressure chambers is effectively prevented via the recess. It can be provided that a plurality of groove-shaped bulges are provided, communicate the wells on the one hand with a pressure medium line and on the other hand in each case with a pressure chamber. Thus, the wells can be used to supply pressure to the pressure chambers.

If pressure medium is present in the depressions, there is the additional advantage that lubricant is supplied to the areas moved relative to one another during a pivoting movement of the disk-shaped section relative to the output element or the drive element.

The recess may also be formed as a backdrop of a Verrieglungsmechanismus in which engages a locking element to produce a releasable mechanical locking between the drive element and the output element.

Alternatively, an insert may be provided in the recess to avoid hydraulic short circuits between the pressure chambers. The insert may be formed as a sliding element.

As an alternative to the groove-shaped formation of the bulge, embodiments are conceivable in which the bulge is massive, i. as excess material on the spring element facing side of the disc-shaped portion is formed. This can be formed integrally with the disk-shaped portion, or manufactured separately for this and force, positively or materially secured thereto.

Advantageously, the bulge projects beyond the fastening elements in the axial direction at least in places or flush with them.

The first side cover can, for example, by means of non-cutting forming process, for example a deep drawing process, by means of a sintering process, a metal or plastic injection molding process, by casting, forging or stamping package. The bulges can be provided with friction-reducing layers or corrosion protection layers or covered with a jacket of a sliding or protective material.

Brief description of the drawings

Figur 1

nur sehr schematisch eine Brennkraftmaschine,

Figur 2

einen Längsschnitt durch eine erfindungsgemäßen Vorrichtung zur variablen Einstellung der Steuerzeiten von Gaswechselventilen einer Brennkraftmaschine,

Figur 3

einen Querschnitt durch die erfindungsgemäße Vorrichtung entlang der Linie III-III in Figur 2,

Figur 4

einen Draufsicht auf die Vorrichtung entlang des Pfeils IV in Figur 2,

Figur 5

eine Darstellung gemäß Figur 4, wobei ein Federdeckel nicht dargestellt ist.

Further features of the invention will become apparent from the following description and from the drawings in which an embodiment of the invention is shown in simplified form. Show it:

FIG. 1

only very schematically an internal combustion engine,

FIG. 2

a longitudinal section through a device according to the invention for the variable adjustment of the timing of gas exchange valves of an internal combustion engine,

FIG. 3

a cross section through the device according to the invention along the line III-III in FIG. 2 .

FIG. 4

a plan view of the device along the arrow IV in FIG. 2 .

FIG. 5

a representation according to FIG. 4 , wherein a spring cover is not shown.

Detailed description of the drawings

In FIG. 1 schematically an internal combustion engine 1 is sketched, wherein a seated on a crankshaft 2 piston 3 is indicated in a cylinder 4. The crankshaft 2 is in the illustrated embodiment via a respective traction drive 5 with an intake camshaft 6 and exhaust camshaft 7 in combination, wherein a first and a second device 11 for the variable adjustment of the timing of gas exchange valves 9, 10 for a relative rotation between the crankshaft 2 and the camshafts 6, 7 can provide. Cams 8 of the camshafts 6, 7 actuate one or more intake gas exchange valves 9 or one or more exhaust gas exchange valves 10.

The FIGS. 2 and 3 show a device 11 according to the invention in the longitudinal or cross section. The device 11 has a drive element 13, an output element 14 and two side covers 15, 16, which are arranged on axial side surfaces of the drive member 13 and secured by screws 12 thereto. The output element 14 is designed in the form of an impeller and has a substantially cylindrically designed hub member 17, extending from the outer cylindrical surface area wings 18 in the radial direction outwards.

Starting from an outer peripheral wall 19 of the drive element 13, projections 20 extend radially inwards. In the illustrated embodiment, the projections 20 are formed integrally with the peripheral wall 19. The drive element 13 is mounted by means of radially inner circumferential walls of the projections 20 relative to the output element 14 rotatably mounted on this.

The drive element 13 is provided with a sprocket 21, via which by means of a chain drive, not shown, torque can be transmitted from the crankshaft 2 to the drive member 13. The output member 14 is rotatably connected in the assembled state with the camshaft, not shown in these figures, rotatably connected.

Within the device 11, a pressure chamber 22 is formed between each two circumferentially adjacent projections 20. Each of the pressure chambers 22 is circumferentially bounded by adjacent projections 20, axially of the side covers 15, 16, radially inwardly of the hub member 17, and radially outward of the peripheral wall 19. In each of the pressure chambers 22 protrudes a wing 18, wherein the wings 18 rest against both the side covers 15, 16, and on the peripheral wall 19. Each wing 18 thus divides the respective pressure chamber 22 into two oppositely acting pressure chambers.

By pressurizing a group of pressure chambers and depressurizing the other group, the phase position of the drive element 13 to the output element 14 and thus the phase angle of the camshaft 6, 7 to the crankshaft 2 can be varied. By pressurizing both groups of pressure chambers, the phase position can be kept constant.

The FIGS. 4 and 5 show a plan view of the device 11 along the arrow IV FIG. 2 , where in FIG. 5 a spring cover 34 is not shown. The side cover 15 has a disk-shaped portion 23 and four fastening elements 24 and consists of a steel sheet. The fastening elements 24 are designed in the form of clamping nuts, which are fastened in a form-fitting manner in openings 33 of the disk-shaped section 23. In this case, the clamping nuts 24 protrude in the axial direction from the side surface of the disk-shaped section 23 facing away from the drive element 13. The clamping nuts 24 are each provided with an internal thread into which the screws 12 engage such that the rotationally fixed connection between the side covers 15, 16 and the drive element 13 is made. In this case, two of the four screws 12 project out of the respective clamping nut 24 in the axial direction. The length of the other screws 12 is chosen such that they do not protrude from the clamping nuts 24 in the assembled state.

Upstream of the clamping nuts 24, a biased spring element 25 (Figures 2 and 4) is provided in the form of a coil spring. The coil spring is encompassed by a spring cover 34 and has a plurality of concentric spring coils 26 of different diameters. In this case, an end of the outermost spring coil 26 engages on the area protruding from the clamping nut 24 region of the first screw 12a ( FIG. 3 ). In the further course, the outermost spring winding 26 is radially supported by the region of the second screw 12b protruding from the clamping nut 24. One end of the innermost spring coil 26 engages a protruding from the output member 14 Pin 27 on. At the same time, the innermost spring coil 26 is supported radially inwardly on two further pins 27 projecting from the driven element 14. Thus, the biased spring element 25 is connected to both the drive member 13 and the output member 14 such that a torque between these components is mediated. This can serve, for example, to adjust the output element 14 in the case of insufficient supply of pressure medium to the device 11 in a base position or to adjust different adjustment speeds in the direction of earlier or later control times of the gas exchange valves 9, 10.

During operation of the internal combustion engine 1, the spring element 25 is excited to axial and radial vibrations, whereby individual spring coils 26 can dip into the region between the fastening elements 24. In addition to increasing the friction, there is a risk that the dipping spring coil 26 is clamped between the fasteners 24, whereby the function of the device 11 is limited. In addition, increased wear on the spring element 25 occurs, and there is a risk that the spring element 25 breaks due to the increased load.

To prevent this, five recesses 28 are provided on the disk-shaped portion 23, which extend in the direction of the spring element 25. The bulges 28 are formed by means of a chipless forming process, so that on the first side cover 15 recesses 29 are formed on the output member 14 side facing. Three first recesses 29 a are arranged in the region of pressure chambers 22 outside a pivoting range of the corresponding blade 18. A second recess 29b is arranged in a pivoting region of a wing 18, wherein the extension of the recess 29b in the circumferential direction is chosen smaller than the corresponding extent of the wing 18. A third recess 29c is arranged in the region of one of the projections 20, wherein the extension of Recess 29c is selected smaller in the circumferential direction, as the corresponding extension of the projection 20. In this way, a hydraulic short circuit avoided between two adjacent pressure chambers. In addition, a loading member 30 is inserted into the second recess 29b to further reduce the leakage between the pressure chambers and to improve the sliding contact between the first side cover 15 and the output member 14.

The bulges 28 are formed and arranged such that each spring coil 26 faces each bulge 28 in the axial direction.

If the spring coils 26 of the spring element 25 are excited to axial oscillations during operation of the internal combustion engine 1, the bulges 28 prevent the spring coils 26 from entering the region between the clamping nuts 24. In addition, the vibration amplitude is reduced and dampens the vibration. Thus, damage to the spring member 25 is prevented and reduces the stress caused by the vibrations. The axial side surfaces of the bulges 28 may be provided with a friction-reducing layer, for example a Teflon layer, or a wear-resistant layer.

The output element 14 has a receptacle 31, in which an unillustrated, axially displaceable locking pin is received. The disc-shaped portion 23 has a slotted portion 32, into which the locking pin can engage in a certain phase position of the output element 14 relative to the drive element 13 in order to form a releasable, mechanical coupling between these two components. The slide 32 also projects out of the disk-shaped portion 23 and can serve as an axial stop for the spring element 25 in addition to the bulges 28.

reference numeral

1

Internal combustion engine

2

crankshaft

3

piston

4

cylinder

5

traction drive

6

intake camshaft

7

exhaust

8th

cam

9

Inlet gas exchange valve

10

Auslassgaswechselventil

11

contraption

12

screw

13

driving element

14

output element

15

side cover

16

side cover

17

hub element

18

wing

19

peripheral wall

20

head Start

21

Sprocket

22

pressure chamber

23

disc-shaped section

24

fastener

25

spring element

26

spring coil

27

pen

28

bulges

29abc

deepening

30

insertion element

31

admission

32

scenery

33

opening

34

spring cover

Claims (8)

1. Device (11) for the variable adjustment of the timing of gas exchange valves (9, 10) of an internal combustion engine (1), having

   - a drive input element (13), a drive output element (14) and at least one side cover (15),

   - wherein the drive input element (13) can be drive-connected to a crankshaft (2) of the internal combustion engine (1),

   - wherein the drive output element (14) can be drive-connected to a camshaft (6, 7) of the internal combustion engine (1) and is arranged so as to be pivotable relative to the drive input element (13),

   - wherein the side cover (15) is arranged on an axial side surface of the drive output element (14) or of the drive input element (13) and is connected rotationally conjointly to the drive input element (13) or to the drive output element (14),

   - wherein a spring element (25) is arranged on that side of the side cover which faces away from the drive input and drive output elements (13, 14), and

   - wherein the side cover (15) has a disc-shaped section (23) from which multiple fastening elements (24) project in the axial direction, which fastening elements are arranged on that side of the side cover (15) which faces away from the drive input element (13), characterized in that

   - the disc-shaped section (23) has, on the side surface facing toward the spring element (25), at least one protuberance (28) which is situated opposite at least one spring winding (26) of the spring element (25) in the axial direction of the device (11).
2. Device (11) according to Claim 1, characterized in that the protuberance (28) limits an axial movement of the spring winding (26) such that said spring winding cannot protrude into a region radially to the inside of the fastening elements (24).
3. Device (11) according to Claim 1, characterized in that the protuberance (28) is formed in one piece with the disc-shaped section (23).
4. Device (11) according to Claim 1, characterized in that the extent of the protuberance (28) in the radial direction of the disc-shaped section (23) is formed such that each spring winding (26) of the spring element (25) is situated opposite the protuberance (28) in the axial direction.
5. Device (11) according to Claim 1, characterized in that, on the side facing away from the spring element (25), the disc-shaped section (23) has a depression (29) in the region of the protuberance (28).
6. Device (11) according to Claim 5, characterized in that the device (11) has pressure chambers which are separated by vanes (18) and projections (20), in that the depression is arranged in the region of the pressure chambers, vanes (18) and projections (20), and in that components from the group comprising vanes (18) and projections (20) are pivotable relative to the depression (29), wherein the depression (29) is arranged outside the pivoting range of the pivotable components.
7. Device (11) according to Claim 1, characterized in that the protuberance (28) is in the form of a surplus of material on that side of the disc-shaped section (23) which faces toward the spring element (25).
8. Device (11) according to Claim 1, characterized in that the protuberance (28) projects beyond the fastening elements (24) in the axial direction at least in regions, or terminates flush with said fastening elements.

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