DE102010025882A1 - Device for changing the relative angular position of a camshaft relative to a crankshaft of an internal combustion engine - Google Patents

Abstract

The invention relates to a device (1) for changing the relative angular position of a camshaft (2) with respect to a crankshaft of an internal combustion engine, the device (1) comprising a drive element (3) driven by the crankshaft and mounted rotatably with respect to the camshaft (2) is, wherein between the drive element (3) and the camshaft (2) at least two hydraulic chambers are formed, which can be acted upon with a pressure fluid in order to set a defined relative rotational position between the drive element (3) and the camshaft (2), the device (1) has a housing (4) in which the drive element (3) is arranged, the device (1) further comprising a pressure accumulator (5) which, designed as a spring-loaded piston-cylinder element, has a pressure chamber (6) for pressurized fluid which is in fluidic connection with a fluid line (7), the pressure accumulator (5) having a pressure accumulator housing (8) and wherein the pressure accumulator housing (8) has a bore (9) for receiving a piston (10). In order to enable a simplified manufacture and assembly of the pressure accumulator, the invention provides that the pressure accumulator housing (8) is designed as a separate part and at one axial end of the bore (8) has an end face (11) that corresponds to the diameter of the bore (8) has a corresponding circular opening (12), the pressure accumulator housing (8) placed with the end face (11) directly and in particular free of a cover element on a wall (13) of the housing (4) of the device (1) and fastened here is.

Description

The invention relates to a device for changing the relative angular position of a camshaft relative to a crankshaft of an internal combustion engine, wherein the device comprises a driven by the crankshaft drive element which is rotatably mounted relative to the camshaft, wherein between the drive element and the camshaft at least two hydraulic chambers are formed, which are acted upon by a pressurized fluid to set a defined relative rotational position between the drive element and the camshaft, wherein the device comprises a housing in which the drive element is arranged, wherein the device further comprises a pressure accumulator which, as a spring-biased piston-cylinder Element formed having a pressure chamber for pressurized fluid, which is in fluid communication with a fluid line, wherein the pressure accumulator has a pressure accumulator housing and wherein the pressure accumulator housing has a bore for receiving a Ko lbens has.

Background of the invention

Camshaft adjusters, particularly those that operate hydraulically, are well known in the art. In the hydraulic camshaft adjuster an impeller is present in which wings are molded or arranged. The wings are located in hydraulic chambers, which are incorporated in an outer rotor. By appropriate action on the respective side of the hydraulic chambers with hydraulic fluid, an adjustment of the inner rotor (connected to the camshaft) can take place relative to the outer rotor between an "early stop" and a "late stop". The flow of hydraulic oil is controlled by an electrically controlled directional control valve. The transmission of the rotational movement of the crankshaft to the outer rotor is usually via a belt or a chain.

A camshaft adjusting device of the type mentioned is for example from the EP 1 985 813 A2 and from the DE 39 29 619 A1 known. Again, the adjustment of the relative rotational position between the crankshaft and camshaft takes place hydraulically. So that hydraulic fluid is always available with sufficient pressure, the camshaft adjuster comprises a pressure accumulator. Via a connecting bore in the camshaft adjuster or in adjacent components (cylinder head), pressurized fluid can be directed into the pressure accumulator. Here it displaces a spring-biased piston by one piston stroke and is thus available under pressure in the pressure accumulator. If required, pressure fluid can be withdrawn from the pressure accumulator again, the spring displaces the piston and thus maintains the pressure in the fluid upright.

The pressure accumulator has an accumulator housing, which must be closed at the end with a lid in order to make it pressure-tight. This has a corresponding manufacturing effort and costs result. Thus, a separate channel for feeding the accumulator must be made (drilled) and then (partially) closed again. After mounting the moving parts of the pressure accumulator system, the pressure accumulator must be closed or sealed with an additional cover.

Object of the invention

The present invention has the object, a device of the type mentioned in such a way that a simplified production and installation of the pressure accumulator is possible. This should make the production of the camshaft adjuster overall cheaper. By reducing the required components of the pressure accumulator also a lighter construction should be possible.

Summary of the invention

The solution of this problem by the invention is characterized in that the pressure accumulator housing is formed as a separate part and at one axial end of the bore has an end face which has a diameter of the bore corresponding circular opening, wherein the pressure accumulator housing with the front side directly and in particular placed free of a cover element on a wall of the housing of the device and secured here.

The pressure accumulator housing may have a substantially cylindrical shape. It can be fixed on the housing (in particular on the cylinder head housing) by means of a screw connection.

In the region of the end face of the pressure accumulator housing, a seal, in particular a ring seal, can be arranged, which cooperates with the wall of the housing.

The piston in the pressure accumulator housing is usually biased by means of a spring element, in particular by means of a helical spring.

In the bore of the pressure accumulator housing a sleeve is preferably used, the inner cylindrical surface forms the track for the translational movement of the piston. The sleeve may be provided with limiting means which insert the piston in the pressure accumulator housing Prevent the condition from leaving the pressure accumulator housing. These limiting means may be formed by at least one nose-like, radially inwardly directed projection formed by plastic deformation of material of the sleeve. In this case, preferably, a plurality, preferably three to five, nose-like projections are present, which are preferably arranged equidistant around the circumference of the sleeve around.

The sleeve is preferably pressed into the bore of the accumulator housing and / or glued.

Thus, the invention proposes a simplified manufacture and assembly of the pressure accumulator in a mounting housing (accumulator housing) in a hydraulic camshaft adjuster.

The pressure accumulator is mounted in a mounting housing (pressure accumulator housing) so that the flange surface of the cylinder head forms a surface bounding the pressurized space. Thus, no additional lid is more to seal the pressurized space of the accumulator required because after mounting the attachment housing (pressure accumulator housing) on the engine, the seal directly through the cylinder head (or by another engine component), with a suitable seal is provided.

A separate oil passage for feeding and emptying the pressure accumulator in the mounting housing is also no longer necessary, since the pressure accumulator can work directly via an existing in the cylinder head oil passage and the pressurized space of the pressure accumulator can open directly to this.

The pressure accumulator is thus arranged in a mounting housing so that a flange of the cylinder head or other engine component takes over the cover function, thus limiting the pressurized space of the pressure accumulator and / or fixed the components of the pressure accumulator. Thus, an additional cover for the accumulator omitted. An additional oil passage to supply the accumulator can also be omitted.

Brief description of the figures

In the drawings, an embodiment of the invention is shown. Show it:

1 the partially sectioned side view of a camshaft adjuster of an internal combustion engine,

2 the side view through a pressure accumulator in a sectional view, wherein the pressure accumulator is part of the camshaft adjuster,

3 the side view through a sleeve in a sectional view, wherein the sleeve is part of the pressure accumulator, and

4 in a perspective view of the sleeve according to 3 ,

Detailed description of the figures

In 1 is a camshaft adjuster 1 an internal combustion engine shown. The camshaft adjuster 1 serves in a known manner, by means of a hydraulically operated (not shown) impeller an adjustment of an inner rotor, with the camshaft 2 the internal combustion engine is connected, relative to a drive element (stator) 3 so that an adjustment can be made between an "early stop" and a "late stop". The camshaft adjuster 1 has a pulley driven by the crankshaft of the internal combustion engine by means of a belt 18 , The drive element 3 rotates during operation of the internal combustion engine with camshaft speed about an axis of rotation.

This structure is basically known, including on the DE 39 29 619 A1 express reference is made.

The camshaft adjustment system also includes a housing 4 , Which in this case is the cylinder head housing of the internal combustion engine. This case 4 has a wall 13 to which an actuator 19 screwed for the axial displacement of a central valve. Similarly, to the wall 13 an accumulator 5 screwed.

The accumulator 5 is designed as a piston-cylinder system. He has a piston 10 on, the translationally displaceable in a bore 9 in a pressure accumulator housing 8th is arranged. This will create a pressure chamber 6 increased or decreased, can be stored in the pressure fluid. The storage of pressurized fluid takes place by the piston 10 against the spring force of a spring element 15 is moved in the form of a coil spring. This concept of a pressure accumulator is known as such.

Essential for the present invention, however, is that the pressure accumulator housing 9 an opening in an axial end region 12 has, which is formed circular and the diameter of the bore 9 having. In this area of the pressure accumulator housing 8th becomes a flat face 11 formed, which is formed and provided directly on the wall 13 of the housing 4 set and fixed there. In the mouth area of the wall 13 to the accumulator housing 8th ends a fluid line 7 (Oil supply hole in the cylinder head), with the pressure chamber 6 can be supplied with hydraulic oil. In particular, the frontal region of the pressure accumulator housing 8th where he is on the wall 13 rests, free of a cover element, as is the case in the prior art. Rather, the wall acts 13 of the housing 4 itself as a sealing cover of the accumulator housing 8th , For this purpose is in an annular groove in the face 11 the accumulator housing 8th a seal 14 arranged on the wall 13 is applied.

From the enlarged view of a minor variant of the pressure accumulator 5 according to 2 Show some details of the proposed solution. First, here is a drain hole 20 to mention. Furthermore, it can be seen here that in the bore 9 the accumulator housing 8th a sleeve 16 inserted (pressed and / or glued), with its inwardly directed cylindrical surface, the tread for the piston 10 forms.

Again, best of all 3 and 4 can be seen, are in the axial end region of the sleeve 16 limiting means 17 provided in the mounted state of the pressure accumulator 5 prevent the spring-loaded piston 10 from the sleeve 16 or the pressure accumulator housing 8th can fall out. For this purpose, nose-shaped caulking of the material of the sleeve 16 provided, which extend radially inwardly and so an axial stop for the piston 10 form. The sleeve 16 acts as a tread for the piston 10 and also improves its leadership; This ensures optimum running properties.

The accumulator 5 So has a separate accumulator housing (mounting housing) 8th on, on the case 4 (Cylinder head housing) is fastened by means of screws. The accumulator 5 with its accumulator housing 8th is mounted so that the pressure chamber 6 limiting area through the wall 13 of the housing 4 (Cylinder head) is formed.

The piston 10 is in the accumulator 5 - As explained - through the sleeve 16 with projections 17 (Imprints) fixed so that the components of the pressure accumulator 5 be kept in their mounting position during transport and installation. The projections 17 furthermore offer the advantage that the piston 10 can be limited in his stroke and not on the wall 13 of the housing 4 (Cylinder head) can hit.

The fixation of the components in the installed state can alternatively also by the wall 13 to be taken over by yourself.

The function of the sleeve 16 (Fixation of the piston and thus the pressure accumulator components) can also be taken over by impressions or projections directly in the pressure accumulator housing, waiving this.

It is also possible the unfixed installation of the component of the accumulator, but then special handling arrangements for transport and assembly are required.

LIST OF REFERENCE NUMBERS

1

Device (Camshaft adjuster)

2

camshaft

3

driving element

4

Housing (cylinder head housing)

5

accumulator

6

pressure chamber

7

fluid line

8th

Accumulator housing

9

drilling

10

piston

11

front

12

opening

13

wall

14

Seal (ring seal)

15

Spring element (coil spring)

16

shell

17

Limiting means (nose-shaped projection)

18

pulley

19

actuator

20

final hole

QUOTES INCLUDE IN THE DESCRIPTION

This list of the documents listed by the applicant has been generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Cited patent literature

• EP 1985813 A2 [0003]
• DE 3929619 A1 [0003, 0022]

Claims (10)

Contraption ( 1 ) for changing the relative angular position of a camshaft ( 2 ) relative to a crankshaft of an internal combustion engine, wherein the device ( 1 ) a driven by the crankshaft drive element ( 3 ), which is opposite the camshaft ( 2 ) is rotatably mounted, wherein between the drive element ( 3 ) and the camshaft ( 2 ) at least two hydraulic chambers are formed, which can be acted upon by a pressurized fluid to a defined relative rotational position between the drive element ( 3 ) and the camshaft ( 2 ), the device ( 1 ) a housing ( 4 ), in which the drive element ( 3 ), wherein the device ( 1 ) continue to have an accumulator ( 5 ), which, designed as a spring-biased piston-cylinder element, a pressure chamber ( 6 ) for pressurized fluid which is connected to a fluid line ( 7 ) is in fluid communication, wherein the pressure accumulator ( 5 ) an accumulator housing ( 8th ) and wherein the accumulator housing ( 8th ) a hole ( 9 ) for receiving a piston ( 10 ), characterized in that the accumulator housing ( 8th ) is formed as a separate part and at one axial end of the bore ( 8th ) an end face ( 11 ) having a diameter of the bore ( 8th ) corresponding circular opening ( 12 ), wherein the accumulator housing ( 8th ) with the front side ( 11 ) directly and in particular free of a cover element on a wall ( 13 ) of the housing ( 4 ) of the device ( 1 ) and attached here. Apparatus according to claim 1, characterized in that the pressure accumulator housing ( 8th ) has a substantially cylindrical shape. Apparatus according to claim 1, characterized in that the pressure accumulator housing ( 8th ) on the housing ( 4 ) is determined by means of a screw connection. Apparatus according to claim 1, characterized in that in the region of the front side ( 11 ) of the pressure accumulator housing ( 8th ) a seal ( 14 ), in particular a ring seal, which is connected to the wall ( 13 ) of the housing ( 4 ) cooperates. Device according to claim 1, characterized in that the piston ( 10 ) in the accumulator housing ( 8th ) by means of a spring element ( 15 ), in particular by means of a coil spring, is biased. Apparatus according to claim 1, characterized in that in the bore ( 9 ) of the pressure accumulator housing ( 8th ) a sleeve ( 16 ), the inner cylindrical surface of the track for the translational movement of the piston ( 10 ). Device according to claim 6, characterized in that the sleeve ( 16 ) with limiting means ( 17 ) are provided, the piston ( 10 ) in the accumulator housing ( 8th ) inserted state leaving the accumulator housing ( 8th ) prevent. Apparatus according to claim 7, characterized in that the limiting means ( 17 ) are formed by at least one nose-like, radially inwardly directed projection, which by plastic deformation of material of the sleeve ( 16 ) is formed. Apparatus according to claim 8, characterized in that a plurality, preferably three to five, nose-like projections ( 17 ), which are preferably equidistant around the circumference of the sleeve ( 16 ) are arranged around. Device according to claim 6, characterized in that the sleeve ( 16 ) into the hole ( 9 ) of the pressure accumulator housing ( 8th ) is pressed and / or glued.

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