WO2010020492A1

WO2010020492A1 - Device for variably adjusting the control times of gas exchange valves of an internal combustion engine

Info

Publication number: WO2010020492A1
Application number: PCT/EP2009/059221
Authority: WO
Inventors: Jürgen Weber; Markus KÖRBER
Original assignee: Schaeffler Kg
Priority date: 2008-08-19
Filing date: 2009-07-17
Publication date: 2010-02-25
Also published as: DE102008038327A1

Abstract

The invention relates to a device (11) for variably adjusting the control times of gas exchange valves (9, 10) of an internal combustion engine (1) comprising a driving element (12), an output element (14), and at least one side cover (15, 16), wherein the driving element (12) can be brought into a driving connection with a crankshaft (2) of the internal combustion engine (1), wherein the output element (14) can be brought into a driving connection with a camshaft (6, 7) of the internal combustion engine and is arranged in a swiveling manner with respect to the driving element (12), wherein within the device (11) at least one pressure chamber (30, 31) is provided which is bounded in the axial direction by the side cover (15, 16), wherein the side cover (15, 16) is arranged in a rotationally fixed manner with respect to the driving element (12) or the output element (14) and wherein a sealing element (26) is provided between a side surface (21) of the side cover (15, 16) and a side surface (20) opposite said side surface of the component (12, 14) arranged in a rotationally fixed manner with respect to said side cover.

Description

Name of the invention

Device for the variable adjustment of the timing of gas exchange valves of an internal combustion engine

description

Field of the invention

The invention relates to a device for variably setting 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 in drive connection with a camshaft of the internal combustion engine can be brought and is arranged pivotably to the drive element, wherein within the device at least one pressure chamber is provided, which is delimited in the axial direction of the side cover, wherein the side cover is rotationally fixedly arranged to the drive element or the driven element and wherein a sealing element between a side surface of the Side cover and one of these opposite side surface of the rotationally fixed to this arranged component is provided.

Background of the invention

In modern internal combustion engines devices for variable adjustment of the timing of gas exchange valves are used to make the phase relation between the crankshaft and camshaft in a defined angular range, between a maximum early and a maximum late position variable. The device comprises a drive element, which is in drive connection with a crankshaft of the internal combustion engine, an output element, which is in drive connection with the camshaft, and a hydraulic actuator, with at least one pressure chamber, via which the phase relation between the over which the phase relation between the drive element and output element and thus the camshaft to the crankshaft can be variably adjusted.

Such a device is known for example from US 6,758,178 B2. The device comprises an output element which is arranged rotatably to a drive element, wherein the drive element is in drive connection with the crankshaft and the output element is non-rotatably connected to the camshaft. In the axial direction, the device is limited by a side cover which is rotatably connected to the drive element. The output element, the drive element and the side cover define a plurality of pressure chambers, each of the pressure chambers is divided by a wing into two oppositely acting pressure chambers. By supplying pressure medium to or removing pressure medium from the pressure chambers, the vanes are displaced within the pressure chambers, whereby a targeted rotation of the output element to the drive element and thus the camshaft to the crankshaft can be effected.

In order to reduce the leakage of pressure medium between the drive element and the side cover out of the device (external leakage), a sealing ring is provided, which is arranged in a circumferential groove of the drive element. The sealing ring rests on the one hand on the groove bottom of the groove and on the other hand on the drive element facing side surface of the side cover and extends along the entire circumferential direction of the device. During assembly of the device, the sealing ring is inserted into the circumferential groove. Subsequently, the side cover is positioned and fastened by screws to the drive element. In this case, the sealing ring is biased on both the groove bottom of the groove and the axial side surface of the side cover, whereby the pressure medium is prevented from exiting the device.

A disadvantage of this embodiment, the high assembly costs and high error rate during assembly. On the one hand, the self-contained sealing ring must be inserted into the groove provided for this purpose. This elaborate process step carries the risk of incorrect installation, if the sealing ring is not completely located in the groove. As a result, in the mounted device, the sealing ring between the drive element and the side cover can be arranged partially outside the groove, which leads to increased leakage and thus to lower response and adjustment speeds of the device and to fluctuating phase angles during operation of the internal combustion engine , Likewise, a first properly positioned sealing ring can automatically misalign before the side cover is mounted on the drive element, for example, on the way to the next processing station or during positioning and joining of the side cover to the drive element.

Object of the invention

The invention has for its object to provide a device for variable adjustment of the timing of gas exchange valves of an internal combustion engine, the external leakage is to be minimized process reliable.

The object is achieved in that the sealing element is material or positively connected to one of the opposing side surfaces. Thus, a malpositioning of the sealing element during assembly and an automatic mispositioning is reliably prevented until the assembly of the side cover.

It can be provided that the sealing element is formed as an at least partial coating on one of the opposing side surfaces. In this case, the coating can be applied, for example, in a screen printing process. Advantageously, it may be provided that at least part of the coated side surface is not covered by the sealing element. The coating of at least one of the side surfaces, in particular in a screen printing process, represents a cost-effective method for realizing the sealing element. If the side surface is only partially coated, the material of the side cover lies directly against the material of the rotatably to this arranged component. Thus, there is no danger that after the final assembly of the device, a setting process in the screw assembly, by means of which the side cover is attached to the drive element or the driven element, occurs. A creeping increasing external leakage and a creeping decreasing performance of the device can be avoided.

Alternatively or additionally, it can be provided that one of the opposing side surfaces is formed with a circumferential groove in the circumferential direction of the device, wherein the sealing element is arranged within the groove. Thus, the disadvantages that can occur by a setting process in the screw, can be safely avoided.

The sealing element can, for example, be injection-molded onto a surface, for example the side surface or the groove bottom of the groove, cast-on, vulcanized, glued or applied in a screen-printing process or otherwise connected in a materially bonded manner to the surface.

In an alternative embodiment, it is provided that the groove is at least partially tapered to the side surface and the sealing element has a maximum width which is greater than the opening width of the groove. During assembly of the sealing element, the latter is "clipped" into the groove and thus captively received in it, incorrect assembly can be easily recognized and eliminated, whereby the groove can be formed along its entire length with a tapered groove structure at which the holding functionality is formed.

Advantageously, the volume of the sealing element is smaller than the volume of the groove. This prevents overfilling of the groove, which could lead to higher external leakage and functional impairment of the device. In a concretization of the invention, it is proposed that the sealing element is designed in such a way that, after being introduced into the groove, it has a projection to the side surface.

The sealing element may for example consist of a polymer plastic.

Brief description of the drawings

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

FIG. 1 shows very schematically an internal combustion engine,

FIG. 2 shows a longitudinal section through a first embodiment according to the invention of a device for changing the control times of gas exchange valves of an internal combustion engine,

Figure 3 is a plan view of the device of Figure 2 without a second

Side cover along the arrow IM,

FIG. 4 shows the detail Z from FIG. 2 before the assembly of the second side cover,

FIG. 5 shows the detail Z from FIG. 2 after mounting the second side cover;

FIG. 6 shows the detail Z from FIG. 2 of a second invention

Embodiment of a device, after mounting the second side cover,

FIG. 7 shows the detail Z from FIG. 2 of a third invention

Embodiment of a device before mounting the second side cover. Detailed description of the drawings

1 shows 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, with a first and a second device 11 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 inlet gas exchange valves 9 or one or more Auslassgaswechselventile 10. Likewise, it may be provided only one of the camshafts 6, 7 with a device 11, or provide only a camshaft 6, 7, which with a Device 11 is provided.

Figures 2 and 3 show a first embodiment of a device 11 according to the invention in longitudinal or in plan view. The device 11 comprises a drive element 12, an output element 14 and two side covers 15, 16, which are arranged on the axial side surfaces 20 of the drive element 12. The output element 14 is designed in the form of an impeller and has a substantially cylindrically designed hub member 17, extend from the outer cylindrical surface in the illustrated embodiment, five wings 18 in the radial direction outwards. The wings 18 are formed separately from the hub member 17 and arranged in vane grooves 19.

Starting from an outer peripheral wall 22 of the drive element 12, five projections 23 extend radially inwardly. In the illustrated embodiment, the projections 23 are integrally formed with the peripheral wall 22. The drive element 12 is arranged by means of radially inner circumferential walls of the projections 23 relative to the output member 14 rotatable thereto. The device 11 further comprises a drive wheel 24, which is formed in the illustrated embodiment as a pulley and rotatably secured to the drive member 12. One each of the side covers 15, 16 is arranged on one of the axial side surfaces 20 of the drive element 12. In each case one side face 21 of the side covers 15, 16 faces a side face 20 of the drive element 12. The drive wheel 24 and the side covers 15, 16 are rotationally fixed to the drive element 12 by means of five screws 27. For this purpose, five openings each are provided in the side covers 15, 16 and the drive wheel 24, which are arranged such that they are aligned with the projections 23. In each case, a screw 27 passes through an opening of the drive wheel 24, the first side cover 15, and a projection 23. In this case engages a threaded portion of the screw 27 in a threaded portion which is formed in the opening of the second side cover 16. About the drive wheel 24 can be transmitted from the crankshaft 2 to the drive member 12 by means of a belt drive, not shown, torque. The output member 14 is rotatably connected in the assembled state with the camshaft 6,7.

Within the device 11, a pressure space 28 is formed between each two adjacent projections 23 in the circumferential direction. Each of the pressure chambers 28 is circumferentially bounded by opposing, substantially radially extending boundary walls 29 of adjacent projections 23, in the axial direction of the side covers 15, 16, radially inwardly of the hub member 17 and radially outwardly of the peripheral wall 22. In each of the pressure chambers 28 protrudes a wing 18, wherein the wings 18 are formed such that they rest against both the side covers 15, 16, and on the peripheral wall 22. Each vane 18 thus divides the respective pressure chamber 28 into two counteracting pressure chambers 30, 31.

The output element 14 is rotatably arranged in a defined Winkeibreich to the drive element 12. The angular range is limited in a direction of rotation of the output element 14 in that the wings 18 on a corresponding boundary wall 29 (early stop 32) of the pressure chambers 28th come to the concern. Similarly, the angular range in the other direction of rotation is limited by the fact that the wings 18 come to rest on the other boundary walls 29 of the pressure chambers 28, which serve as a late stop 33. By pressurizing a group of pressure chambers 30, 31 and pressure relief of the other group, the phase position of the drive element 12 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 30, 31, the phase position can be kept constant.

On the axial side surfaces 20 of the drive element 12, a groove 25 is formed in the embodiment shown in Figures 2 and 3, which rotates in the circumferential direction of the drive element 12. In the groove 25 a sealing element 26 is arranged, which is materially connected to the groove bottom 34. Figures 4 and 5 show the sealing element 26 before or after the assembly of the second side cover 16. Also conceivable are embodiments in which the sealing element 26 is integrally connected to a side wall 35 of the groove 25. Likewise conceivable are embodiments in which the groove 25 is formed in the side covers 15, 16 and the sealing element 26 is arranged in this groove and is integrally connected to the groove bottom or one of the side walls 35.

Before the assembly of the second side cover 16, the sealing element 26 protrudes in the axial direction beyond the side surface 20 of the drive element 12. After assembly of the second side cover 16, its axial side surface 21 rests against the axial side surface 20 of the drive element 13, whereby the projecting region of the sealing element 26 has been set back into the groove 25 by means of the assembly forces during the screwing operation. Thus, the sealing member 26 is under axial bias, whereby the sealing effect between the side surfaces 20, 21 is made. In this case, the volume of the sealing element 26 in each region of the groove 25 is made smaller than the corresponding volume of the groove 25. As a result, an overpressing of the sealing elements 26 avoided, whereby the leakage would be increased and the sealing element 26 could be damaged.

FIG. 6 shows a further embodiment of a device 11. In contrast to the first embodiment, neither the drive element 12 nor one of the side covers 15, 16 has a groove 25. In this embodiment, the sealing element 26 is formed as a coating 36 of the second side cover 16 in the region of the side surface 20 of the drive element 12. The coating 36 is exaggerated in FIG. 6 for better clarity in the axial direction. In this case, as in the first embodiment, the sealing element 26 extends along the entire circumferential direction of the second side cover 16. However, the coating 36 extends in the radial direction only within a partial region of the side face 20 of the drive element 12. The second side cover 16 thus lies outside of Coating 36 directly on the side surface 20 of the housing 13, whereby a setting of the screw assembly is avoided.

The sealing elements 26 illustrated in FIGS. 2 to 6 may be injection-molded, cast on, vulcanized, glued or screen-printed onto the respective support surface, whereby the integral connection between support surface and sealing element 26 is produced. The sealing element 26 is firmly connected to the respective component and thus taken captive.

Figure 7 shows a third embodiment of a device 11. In this embodiment, analogous to the first embodiment, on the side surface 20 of the drive member 12, a groove 25 is formed, in which the sealing element 26 is received. In this case, the sealing element 26 is positively held in the groove 25. For this purpose, the groove 25 tapers to the side surface 21 of the second side cover 16. The opening width B of the groove 25 is smaller than the maximum width b of the sealing element 26 formed while the groove width within the groove 25 is greater than the maximum width b of the sealing element 26 is executed. come next to the illustrated triangular groove shape Also all other groove shapes into consideration, in which the opening width B is formed smaller than an inner width of the groove 25th

This special groove shape can be formed along the entire groove 25, embodiments are also conceivable in which this groove shape is formed only in some locally limited areas, while there is a rectangular groove shape between these areas.

All illustrated sealing elements 26 may for example consist of a polymer plastic. Likewise conceivable are embodiments in which the sealing element 26 is arranged between the first side cover 15 and the drive element 12 or between one or both side covers 15, 16 and the output element 14 in one of the embodiments described.

reference numeral

1 internal combustion engine

2 crankshaft

3 pistons

4 cylinders

5 traction drive

6 intake camshaft

7 exhaust camshaft

8 cams

9 inlet gas exchange valve

10 outlet gas exchange valve

11 device

12 drive element

13 housing

14 output element

15 side covers

16 side covers

17 hub element

18 wings

19 wing groove

20 side surface

21 side surface

22 peripheral wall

23 advantage

24 drive wheel

25 groove

26 sealing element

27 screw

28 pressure chamber

29 boundary wall

30 first pressure chamber 31 second pressure chamber

32 early stop

33 Late stop

34 groove base 35 side wall

36 coating

b width

B opening width

Claims

claims

1. Device (11) for variably setting the control times of gas exchange valves (9, 10) of an internal combustion engine (1) with - a drive element (12), an output element (14) and at least one side cover (15, 16),

- wherein the drive element (12) in drive connection with a crankshaft (2) of the internal combustion engine (1) can be brought,

- Wherein the output element (14) in drive connection with a Nockenwel- Ie (6, 7) of the internal combustion engine (1) can be brought and pivotally to the

Drive element (12) is arranged,

- wherein within the device (11) at least one pressure chamber (30, 31) is provided, which in the axial direction of the side cover (15, 16) is limited, - wherein the side cover (15, 16) rotationally fixed to the drive element (12) or the output element (14) is arranged and

- Wherein a sealing element (26) between a side surface (21) of the side cover (15, 16) and one of these opposite side surface (20) of the rotationally fixed to this arranged component (12, 14) is provided, - characterized in that the sealing element ( 26) is material or positively connected to one of the opposing side surfaces (20, 21).

2. Device (11) according to claim 1, characterized in that one of the opposing side surfaces (20, 21) is formed with a peripheral in the circumferential direction of the device (11) circumferential groove (25), wherein the sealing element (26) within the Groove (25) is arranged.

3. Device (11) according to claim 1, characterized in that the sealing element (26) consists of a polymer plastic.

4. Device (11) according to claim 1, characterized in that the sealing element (26) as an at least partial coating (36) on one of the opposing side surfaces (20, 21) is formed.

5. Device (11) according to claim 1, characterized in that the sealing element (26) is applied to a surface by screen printing.

6. Device (11) according to claim 1, characterized in that the sealing element (26) is injection-molded onto a surface.

7. Device (11) according to claim 1, characterized in that the sealing element (26) is vulcanized to a surface.

8. Device (11) according to claim 1, characterized in that the sealing element (26) is glued to a surface.

9. Device (11) according to claim 2, characterized in that the groove (25) to the side surface (20, 21) is at least partially tapered and the sealing element (26) has a maximum width (b) which is greater than the opening width (B) is the groove (25).

10.Vorrichtung (11) according to claim 2, characterized in that the volume of the sealing element (26) is smaller than the volume of the groove (25).

11. Device (11) according to claim 2, characterized in that the sealing element (26) is designed such that this after insertion into the groove (25) has a projection to a side surface (20, 21).

12. Device (11) according to claim 4, characterized in that at least a part of the coated side surface (20, 21) is not covered by the sealing element (26).