EP2452062A1

EP2452062A1 - Flat gasket

Info

Publication number: EP2452062A1
Application number: EP10724487A
Authority: EP
Inventors: Jens Hoppe
Original assignee: Schaeffler Technologies AG and Co KG
Current assignee: Schaeffler Technologies AG and Co KG
Priority date: 2009-07-04
Filing date: 2010-06-04
Publication date: 2012-05-16
Also published as: WO2011003680A1; CN102472200A; US20120091384A1; DE102009031710A1

Abstract

The invention relates to a flat gasket (1) arranged between a component (5) that is fixed to the cylinder head, and a housing (6) that accommodates a camshaft adjuster, said flask gasket comprising a flat gasket body (1) encompassing a surface (3) to be sealed, wherein on the gasket body (2), a convexity is formed encompassing the surface (3) to be sealed and protruding from the surface of the gasket body (2).

Description

Name of the invention

Flat gasket Description

Field of the invention

The invention relates to a flat gasket, which is arranged between a cylinder head fixed component and a housing which accommodates a camshaft adjuster, with a flat sealing body which engages around a surface to be sealed, wherein on the sealing body surrounding the surface to be sealed, from the surface the sealing body outstanding bulge is formed.

Background of the invention

In modern internal combustion engines, camshaft adjusters are used in order to make the phase relation between crankshaft and camshaft variable within a defined angular range, between a maximum early and a maximum late position. For this purpose, the camshaft adjuster is integrated into a drive train via which torque is transmitted from the crankshaft to the camshaft. This drive rod can be realized for example as a belt, chain or gear drive. Such camshaft adjusters are generally designed as hydraulic swivel motors, for example in vane or axial piston design, with at least two mutually acting pressure chambers. In this case, the pressure medium supply to or the removal of pressure medium from the pressure chambers by means of a hydraulic directional control valve, for example a proportional valve controlled. In DE 42 18 078 C1 a camshaft adjuster is disclosed in axial piston design, which is disposed within a housing which is fixed to a cylinder head. The housing and the cylinder head have aligned openings, which are penetrated by the camshaft adjuster and a camshaft mounted in the cylinder head. The camshaft is non-rotatably connected to an output element of the camshaft adjuster. The housing has a pressure medium channel which communicates with a pressure medium channel formed in the cylinder head and a control valve accommodated in the housing. Thus, pressure medium from a pressure medium pump of the internal combustion engine via the pressure medium channels and the control valve can be distributed to the pressure chambers of the camshaft adjuster.

The housing lies flat against the cylinder head in the region that surrounds the opening. In this case, the region of the openings of the housing and the cylinder head and the region of the pressure medium channels are sealed by means of a plurality of O-ring seals against the environment. The O-ring seals surround the surfaces to be sealed and thus prevent the escape of pressure medium, usually lubricant of the internal combustion engine.

During operation of the internal combustion engine, the cams of the camshaft actuate the gas exchange valves. In this case, the gas exchange valves are opened at auflaufendem cam against the force of a valve spring and closed at the expiring cam by the valve spring. From the opening and closing forces resulting oscillating alternating torques acting on the camshaft and in turn generate pressure peaks in the pressure chambers of the camshaft adjuster. In order to prevent the propagation of these pressure peaks into the lubricant circuit of the internal combustion engine, it is known, for example from DE 10 2007 056 683 A1, to position a ball check valve in the pressure medium channel upstream of the control valve, which permits a pressure medium flow to the control valve, but an opposing pressure medium flow locks. This prevents that pressure peaks propagate into the lubricant system of the internal combustion engine and damage other connected consumers. In addition, an undesired outflow of pressure medium from the pressure chambers of the camshaft lenverstellers prevented, whereby its Verstellgeschwindigkeit increases and phase fluctuations are avoided.

A disadvantage of the known solutions are the high space requirement and the high cost of the check valve and the complicated sealing of the contact point between the cylinder head and the housing receiving the camshaft adjuster.

OBJECT OF THE INVENTION The invention is based on the object of reducing the costs, the space requirement and the assembly costs of an internal combustion engine with a camshaft adjuster, which is accommodated in a housing fastened to the cylinder head. Solution of the task

The object is achieved in that a connected to the sealing body closing element is provided, which is arranged in the region which is encompassed by the circumferential bulge, wherein the closing element is pivotable on the plane of the sealing body and out of this and a channel opening formed in the cylinder head-fixed component or the housing can be closed in a pressure-tight manner by means of the closing element.

The flat gasket is arranged between the housing and a cylinder head fixed component in the region of an opening of the cylinder head fixed component. The housing also has an opening in the region of the opening of the cylinder-head-resistant component. The cylinder head fixed component can be, for example, the cylinder head itself, a cylinder head cover or a crankcase of the internal combustion engine. The housing may, for example, be pot-shaped. The camshaft adjuster is arranged in a receptacle of the housing and encapsulated by means of the housing and the cylinder head fixed component. The openings of the housing and of the cylinder-head-resistant component are produced by a camshaft and / or a component of the camshaft adjuster. lers, whereby these components are in drive connection with each other.

Within the cylinder-head-resistant component or the housing, a first pressure medium channel is formed which has a channel opening on the boundary surface of the component facing the other component. In addition, a second pressure medium channel is formed on the cylinder head fixed component or the housing, which likewise has a channel opening on the boundary surface of the component facing the other component and which can communicate hydraulically with the first pressure medium channel. Pressure medium can be directed to the camshaft adjuster via the pressure medium channels.

In the areas of the channel openings and the openings pressure fluid or lubricant is present during operation of the internal combustion engine. Thus, the contact surface between the housing and the cylinder head-fixed component, which surrounds the openings or channel openings, must be sealed from the environment. For this purpose, the flat gasket has a flat sealing body, for example a metal sheet, which surrounds the surfaces to be sealed. In this case, the flat sealing body is substantially flat with a significantly smaller thickness compared to the other extensions. On the sealing body at least one encircling the surfaces to be sealed bulge is provided, which protrudes from the surface of the sealing body. During attachment of the housing to the cylinder head fixed component, the bulge is elastically compressed, whereby this voltage is applied to both components and the sealing function between the components is produced.

In the region of the first pressure medium channel, a closing element connected to the sealing body is provided, which is pivotable towards and out of the plane of the sealing body. The closing element may be formed, for example, as a flat sheet metal component, wherein the plane may be arranged parallel or perpendicular to the plane of the sealing body. In this case, the closing element is designed and arranged such that it can be pivoted into a position in which it seals the channel opening of the first pressure medium channel in a pressure-tight manner. If the pressure in the second pressure medium channel is higher than the pressure in the first pressure medium channel, the closing element acts on it Force that urges this against the channel opening of the first pressure medium channel and thus closes it. This movement is supported by the spring force of the closing element. Thus, a pressure medium flow is prevented by the second in the first pressure medium channel. With a reverse pressure configuration, the closing element lifts off from the channel opening, as a result of which pressure medium can flow from the first pressure medium channel to the second pressure medium channel. The closing element and the channel opening thus form a check valve. The integration of the closing element in the gasket does not require a separate check valve, which has a positive effect on the costs. In addition, the installation effort and incorrect assembly decreases because the check valve with the flat gasket is installed.

In a further development of the invention, it is proposed that the closing element has a closing body for closing the channel opening and a spring tongue, the spring tongue being connected to the sealing body and the closing body to the spring tongue. The closing element may for example be formed as a flexible paddle, wherein the widened portion of the paddle serves as a closing body for blocking the channel opening of the pressure medium channel. About the spring tongue acting on the closing body (closing) spring force and thus the set pressure can be adjusted. By a longer, thinner and / or narrower spring tongue, the spring force can be lowered, increased by shorter, thicker and / or wider spring tongue. It can be provided that the closing body in the region of the channel opening in abutment against the cylinder head fixed component or to the housing can be brought. Thus, a cost-effective check valve is realized by the channel opening, the closing body and the spring tongue

In addition, it can be provided that a stop for the closing body is formed on the housing and / or the cylinder head fixed component. The stop limits the deflection path of the closing element / closing body away from the channel opening. This prevents the closing element from bending during operation of the internal combustion engine. Furthermore, it can be provided that the closing element / the closing body and the spring tongue are formed integrally with the sealing body. Due to the one-piece design of the closing body with the spring tongue and the spring tongue or the closing element with the sealing body of the flat gasket they can be inexpensively formed from the material of the sealing body.

The closing element formed integrally with the sealing body can be formed by separating the material of the sealing body along a non-self-contained line. Thus, cost-effective sheet metal processing methods, such as punching, can be used for the production of the closing element

In a development of the invention, it can be provided that the closing element projects out of the plane of the sealing body in the region of the channel opening. In this case, the first pressure medium channel opens into a recess of the receiving this component. The closing element connected to the sealing body extends out of the plane of the sealing body into the recess when the first pressure medium channel is depressurized and abuts against the channel opening of the first pressure medium channel.

Alternatively it can be provided that the sealing body has a passage opening in which the closing element is arranged. This embodiment is suitable for use in applications in which pressure medium between a pressure medium channel, which is formed in the cylinder head fixed component and a pressure medium channel, which is formed in the housing to be replaced. In order to allow the passage of pressure medium, a passage opening is formed in the region of the two pressure medium channels on the sealing body, in which a closing element is arranged. In this case, the closing element may be formed in the plane of the Dichtköpers along a non-self-contained line of the sealing body separately. Thus, the closing element is connected only along a short distance compared to its entire circumference with the sealing body, wherein the non-connected part of Closing element is formed out of the plane of the sealing body swung out.

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. FIG. 1 shows a plan view of a first flat gasket according to the invention,

FIG. 2 shows a sectional view along the line M-II of FIG. 1,

FIG. 3 shows the first flat gasket according to the invention in the installed state, wherein the channel opening is blocked,

Figure 4 shows the first gasket according to the invention in the installed state, wherein the channel opening is released, Figure 5 is a second inventive flat gasket in built

Condition, with the channel opening is released.

DETAILED DESCRIPTION OF THE DRAWINGS FIG. 1 shows a flat gasket 1 according to the invention in plan view. The flat gasket 1 consists of a flat sealing body 2 enclosing a surface 3 to be sealed. The flat sealing body 2 extends in a plane, wherein the thickness is made significantly lower compared to the other dimensions of space. On the sealing body 2, which is made of a metal sheet, for example a steel sheet, a circumferential around the sealed surface 3 bulge 4 is formed, which protrudes from the plane of the sealing body 2 (Figure 2). Figures 3 and 4 show the gasket 1 in its installed state. The flat gasket 1 is arranged between a cylinder head 5 of an internal combustion engine and a housing 6. The housing 6 accommodates a camshaft adjuster, not shown, and a hydraulic proportional valve 7 for controlling the pressure medium flows from and to the camshaft adjuster, and is firmly connected to the cylinder head 5, for example by means of screw connections. Due to the assembly forces, the bulge 4 is set back elastically in the direction of the plane of the sealing body 2. Thus, the sealing body 2 is located in the region of the bulges 4 under tension both on the cylinder head 5 and the housing 6, whereby these components are connected to each other within the bulge 4 druckmitteldicht. In this case, the sealing body 2 may be provided with a coating, for example an elastomer coating, at least in the region of the bulges 4 in order to increase the sealing effect.

Within the cylinder head 5, a first pressure medium channel 8 is formed, which communicates with a pressure medium pump, not shown, of the internal combustion engine. The housing-side channel opening 16 of the first pressure medium channel 8 is located opposite a recess 9 of the housing 6. On the flat gasket 1, a passage opening 10 is formed in the region of the recess 9, in which a closing element 11 is arranged. The closing element 11 has no coating, comprises a closing body 12 and a spring tongue 13 and is formed integrally with the sealing body 2. The closing element 11 is arranged in its rest position in the plane of the sealing body 2 and by means of a force out of this plane, in the recess 9, formed pivotable. In this case, a stop 14 arranged in the recess 9 limits the maximum possible deflection path of the closing element 11.

During operation of the internal combustion engine, pressure medium is conveyed from the pressure medium pump via the first pressure medium channel 8 to the closing body 12. By the pending on the closing body 12 pressure this is urged against the stop 14. Thus, the pressure medium passes through the passage opening 10 into the recess 9 and via a second pressure medium channel 15 to the camshaft adjuster, wherein the second pressure medium channel 15 opens via a channel opening 16 in the recess 9. Due to the deflection of the closing element 11, the spring tongue 13 is also pivoted out of its rest position, whereby a restoring force acts on the closing body 12. If the pressure in the second pressure medium passage 15 exceeds the pressure in the first pressure medium passage 8, the closing element 11 is set back into the plane of the sealing body 2 by the restoring force of the spring tongue 13 and the pressure difference until the closing body 12 and the cylinder head 5 comes to bear and the channel opening 16 of the first pressure medium channel 8 closes. The closing element 11 and the channel opening 16 of the first pressure medium channel 8 thus form a check valve which prevents a backflow of pressure medium from the camshaft adjuster into the first pressure medium channel 8.

On the sealing body 2, a second recess 4 is provided, which rotates about the closing element 11, so that both the first pressure medium channel 8 and the recess 9 is sealed off from the surface 3 to be sealed.

FIG. 5 shows a second embodiment according to the invention of a flat gasket 1 in the installed state. In contrast to the first embodiment, the region of the spring tongue 13 connected to the sealing body 2 is here bent out of the plane of the sealing body 2 into the recess 9. Thus, the closing body 12 bears against the housing 6 and closes a channel opening 16 of a first pressure medium channel 8 formed in the housing 6. The closing body 12 is pushed back into the recess 9 by the pressure in the first pressure medium channel 8. Thus, a flow of pressure medium to a second, also formed in the housing 6 pressure medium channel 15 is allowed. If the pressure in the second pressure medium channel 15 exceeds the pressure in the first pressure medium channel 8, then the spring tongue 13 urges the closing body 12 against the channel opening 16 of the first pressure medium channel 8, whereby a pressure fluid reflux into the first pressure medium channel 8 is prevented. Thus, the check valve can also act between pressure medium channels 8, 15, which are formed in the same component (housing 6 or cylinder head 5).

Embodiments are also conceivable in which both embodiments of a closing element 11 are formed on a flat gasket 1. In the event of a housing 6, which receives a pressure accumulator, which is arranged upstream of the proportional valve 7 in addition to the camshaft adjuster and the proportional valve 7, the first embodiment of a closing element 11, a pressure medium flow from the cylinder head 5 in the accumulator allow and lock a backflow, whereby the pressure accumulator also remains filled at decreasing system pressure. The second embodiment of a closing element 11 may be arranged between the pressure accumulator and the proportional valve 7, wherein a pressure medium flow admitted to the proportional valve 7 and a reflux is blocked. Thus, pressure peaks generated in the camshaft adjuster can not propagate into the pressure accumulator

The closing element 11 can be produced, for example, by punching along a non-self-contained line from a flat section of the sealing body 2. The sealing body 2 may be formed, for example, as a metal sheet. The shaping can be produced, for example, by means of chipless forming processes, for example stamping and deep drawing or embossing. In the case of the second embodiment, the spring tongue 13 is bent after punching in the desired shape.

By dimensioning the spring tongue 13 whose spring constant can be adapted to the respective requirements. Longer, thinner and / or narrower spring tongues 13 lead to a lower spring constant, shorter, thicker and / or wider spring tongues 13 to a higher spring constant. Thus, the pressure at which the check valve releases the flow and adjust the sensitivity without additional effort. In addition to a one-piece design of the closing element 11 with the sealing body 2, embodiments are also conceivable in which the closing element 11 is manufactured separately from the sealing body 2 and fixed to it, for example, by means of a welding, adhesive or soldering connection. reference numeral

1 flat gasket

2 sealing bodies

3 surface to be sealed

4 bulge

5 cylinder head

6 housing

7 proportional valve

8 first pressure medium channel

9 recess

10 passage opening

11 closing element

12 closing bodies

13 spring tongue

14 stop

15 second pressure medium channel

16 channel opening

Claims

claims

1. A flat gasket (1) which is arranged between a cylinder head fixed component (5) and a housing (6) which accommodates a camshaft adjuster

- A flat sealing body (1) which surrounds a surface to be sealed (3),

- Wherein on the sealing body (2) surrounding the sealed surface (3), from the surface of the sealing body (2) outstanding bulge (4) is formed,

- characterized in that a closing element (11) connected to the sealing body (2) is provided, which is arranged in the area which is encompassed by the circumferential bulge (4),

- Wherein the closing element (11) on the plane of the sealing body (2) and out of this is pivotable and

- Wherein a in the cylinder head fixed component (5) or the housing (6) formed channel opening (15) of a pressure medium channel (8) by means of the closing element (11) pressure-tight manner is closed.

2. Flat gasket (1) according to claim 1, characterized in that the closing element (11) has a closing body (12) for closing the channel opening (16) and a spring tongue (13), wherein the spring tongue (13) with the sealing body (2 ) and the closing body (12) is connected to the spring tongue (13).

3. Flat gasket (1) according to claim 2, characterized in that on the housing (6) and / or the cylinder head fixed component (5) has a stop (14) for the closing body (12) is formed.

4. Flat gasket (1) according to claim 2, characterized in that the closing body (12) in the region of the channel opening (16) in abutment against the cylinder head fixed component (5) or to the housing (6) can be brought.

5. Flat gasket (1) according to claim 1, characterized in that the closing element (11) is formed integrally with the sealing body (2).

6. Flat gasket (1) according to claim 5, characterized in that the closing element (11) is formed by separating the material of the sealing body (2) along a non-self-contained line.

7. Flat gasket (1) according to claim 1, characterized in that the sealing body (2) has a passage opening (10), in which the closing element (11) is arranged.

8. Flat gasket (1) according to claim 1, characterized in that the closing element (11) in the region of the channel opening (16) protrudes from the plane of the sealing body (2).