DE102007004196B4 - Device for adjusting the camshaft of an internal combustion engine with a two-part lock cover - Google Patents

Abstract

Device (1) for adjusting the camshaft of an internal combustion engine, which has a rotatably connected to a camshaft (2) inner rotor (3) which is rotatably adjustable relative to an outer rotor (4) drivingly connected to a crankshaft, wherein in the outer rotor (4) at least one hydraulic chamber (7) delimited by side walls (5, 6) is subdivided into two subchambers (9, 10) by an element (8) extending radially outwards from the inner rotor (3), and wherein the locking mechanism of FIG Relative movement between the inner rotor (3) and outer rotor (4) has two corresponding axially inserted in corresponding holes of the inner rotor (3) locking pins (11, 12) are present, which can engage in two recesses (13, 14) in one of Locking lid trained side walls (6) are introduced, characterized in that the locking cover (6) consists of two parts (15, 16), wherein each of the parts (1 5, 16) each have a recess (13, 14) for engaging each of a locking pin (11, 12).

Description

Field of the invention

The invention relates to a device for adjusting the camshaft of an internal combustion engine, which has a rotatably connected to a camshaft inner rotor which is rotatably adjustable relative to an outer rotor rotatably connected to a crankshaft, wherein in the outer rotor at least one hydraulic chamber bounded by side walls is introduced, said is divided by a radially outwardly extending from the inner rotor member into two sub-chambers and wherein for locking the relative movement between the inner rotor and outer rotor two inner rotor axially passing through locking pins are provided which can engage in two recesses which are introduced into one of the side walls designed as a locking lid are.

Background of the invention

A camshaft adjusting device of this kind is known from US Pat. No. 6,450,137 B2 known. The device has an inner rotor, which is screwed by a central screw with the camshaft of the internal combustion engine. The outer rotor is connected via a chain or via a toothed belt with the crankshaft in operative connection. Between the inner rotor and the outer rotor can - be initiated via an external hydraulic actuation - a relative rotational movement. For this purpose, the inner rotor is designed as an impeller having grooves for receiving wings. The wings divide a hydraulic chamber into two areas. By appropriate action on the respective section of the hydraulic chamber, adjustment of the inner rotor relative to the outer rotor can take place between an "early stop" and a "late stop".

The camshaft adjuster thus has the function of changing the angular position of the camshaft relative to the crankshaft of the internal combustion engine during operation. The adjustable angular position with the described embodiment is stored in a map in an engine control unit and results from operating parameters of the engine, such as engine load, engine speed, cooling water temperature, etc. During operation of the engine, the camshaft adjuster operates on the vane principle, that is, by generating an oil pressure difference The camshaft adjuster in the hydraulic chambers adjusts in the direction of "early stop" or "late stop".

When starting the engine, the problem arises that there is not enough oil pressure in the engine's oil circuit to keep the phaser in a particular position. The result is that the camshaft phaser starts to swing uncontrollably. Furthermore, noises are caused by the striking of the wings on the outer rotor (stator).

It has become known to solve the mentioned problem in that an axial locking between the inner rotor and a laterally arranged locking cover in the camshaft adjuster is made. Mostly a lock was made in one of the end stop positions "late" or "early". It can be adjusted relatively easily by appropriate positioning of the inner rotor to the outer rotor before mounting the camshaft adjuster the locking clearance. On the one hand, this game must not be too large, as otherwise unwanted noise may occur, on the other hand, it must not be too small, otherwise the locking pin (locking piston) can no longer reliably lock or unlock.

The locking in the end positions "early" and "late" but also has disadvantages, so that there is a desire to be able to make a Verrieglung in a middle position between "early" and "late". The "center lock" differs from the "Endanschlagverrieglung" in that the camshaft adjuster is locked in a defined angular position between the two end positions "early" and "late", which is particularly advantageous when starting the engine.

The above US Pat. No. 6,450,137 B2 This is made possible by two locking pins (locking pistons) that pass axially through the inner rotor. The locking pins can engage with their one axial end in two recesses which are introduced into one of the side walls of the camshaft adjuster designed as a locking cover. The two locking pins are arranged parallel to each other and spaced from each other in the circumferential direction.

A disadvantage of this design is that due to the tolerance chain of the components, d. H. Namely, the locking pins in their holes and the recesses in the locking lid, a locking clearance results, which - in contrast to the one at the Endanschlagsverriegelung - is not adjustable before mounting.

The locking clearance is essentially determined by the geometric distance between the two holes in the inner rotor for receiving the locking pins and the distance between the two locking recesses (locking slots) in the locking cover. The distance is therefore essentially determined by the manufacturing tolerances, wherein in prior art solutions no influence during assembly is possible. Of influence are also the game of locking pins in their mounting holes in the inner rotor, the radial bearing clearance of the inner rotor in the outer rotor, the centering of the locking cover on the outer rotor and the dimensional accuracy of the locking link. All these effects make it particularly difficult to maintain a defined locking clearance in a camshaft adjuster of the generic type.

The DE 100 64 222 A1 shows an adjustable valve timing system for an internal combustion engine, comprising: a rotary member which rotates with one of a crankshaft and a camshaft; a rotation transmission member that is rotatably supported within a predetermined range relative to the rotation member and rotates with the other of the crankshaft and the camshaft; a provided on the rotary member wings; a fluid pressure chamber formed between the rotation member and the rotation transmission member, which is divided by the blade into an advance chamber and a retard chamber; wherein the rotation member and the rotation transmission member are relatively rotated by the fluid pressure supplied to the advance chamber and the retard chamber and wherein the opening and closing time of a valve to be actuated by the camshaft is changed by changing the rotational phase of the camshaft relative to the rotational phase of the crankshaft; a first relative rotation restricting means limiting the relative rotation between the rotation member and the rotation transmission member from the position of maximum advance where the volume of the retard chamber is minimal to the position of greatest retard where the volume of the retard chamber is minimal limited by the blade at an engine start corresponding position where the vane is positioned at about the center of the fluid pressure chamber, and a first restriction by fluid pressure, which is supplied to the retard chamber; and a second relative rotation restricting means that restricts the relative rotation between the rotation member and the rotation transmitting member from the position of greatest retard to the advanced advance position at the position corresponding to the engine start and releases a second constraint by the fluid pressure supplied to the advance chamber.

The DE 100 54 600 A1 10 shows a sliding mode control apparatus for executing sliding mode control of a control subject having a working dead zone of a control amount, characterized in that a linear term of the control quantity is set as a function of a deviation between a target position and an actual position of the control subject.

Object of the invention

The present invention is therefore the object of a camshaft adjuster of the type mentioned in such a way that it is possible to obtain even when using a lock in the middle position between "early" and "late" a largely backlash-free arrangement, so that in particular the Noise level remains low. Furthermore, the function of locking and unlocking should be ensured by choosing an optimal, low game.

Summary of the invention

The solution of this problem by the invention is characterized in that the locking cover of the camshaft adjuster consists of two parts, each of the parts each having a recess for engaging a respective locking pin.

The two parts of the locking cover are preferably each disk-shaped and arranged concentrically to each other. The recesses may be designed like a backdrop, in particular elongated.

The two parts of the locking cover are preferably formed so that they are rotatable in the circumferential direction relative to each other up to a predetermined angle of rotation. This can be set precisely in a very simple way the locking game. One of the parts of the locking cover preferably has protrusions that rise from the base of the part and that are designed to pass through corresponding apertures in the other part of the locking cover. The projections are produced for economic reasons with advantage by a forming process. They can have a cylindrical or hollow cylindrical basic contour. With particular advantage, the openings in the other part of the locking lid are designed as a slot, which provides in a simple way the mentioned possibility to accomplish a relative rotation between the two parts.

In most cases, a plurality of projections and openings are arranged over the circumference of the parts of the locking cover. In particular, it can be provided that four, five or six projections and openings are arranged equidistantly over the circumference of the parts of the locking cover.

In the locking pins facing part of the locking lid, a first recess for exposing the remote from the locking pins in the part of the Locking lid introduced recess may be arranged.

The recesses in the locking cover can be produced by milling or by forming, in particular by an embossing process and / or by a deep-drawing process.

In the remote from the locking pins part of the locking lid, a second recess for entry or passage of formed material of the locking pins facing part of the locking cover may be introduced. This despite a bulged material by forming a generally flat and axially small structure of the locking lid is possible.

The function of the locking cover is on the one hand the sealing of the oil chambers and on the other hand, the transmission of the drive torque from the crankshaft to the camshaft when the camshaft adjuster is axially locked.

With the proposed embodiment of a camshaft adjuster, it is possible to achieve a "center lock" in which when using the two Verrieglungsstifte a precisely adjustable game remains that maintains the functionality of the camshaft adjuster and leads to a favorable performance, especially as regards the noise.

In particular, it does not have to be accepted that in the case of camshaft adjusters of the generic type there is too great a locking clearance, as is often the case in previously known solutions.

Advantageously, no change of the axial space is required, d. H. the total lid width or thickness is unchanged in comparison with prior art solutions.

The proposed solution is also applicable when the camshaft adjuster an additional locking piston for an additional Endanschlagsverriegelung is, as provided in some constructions.

list of figures

• 1 schematisch die Seitenansicht eines Nockenwellenverstellers, der mit einer Nockenwelle verbunden ist,
• 2 eine zu 1 alternative Ausgestaltung des Nockenwellenverstellers,
• 3 die Vorderansicht des Nockenwellenverstellers im Schnitt A-B gemäß 1, dargestellt ohne Nebenaggregate,
• 4 in Explosionsansicht die beiden Teile eines Verriegelungsdeckels des Nockenwellenversteller,
• 5 in perspektivischer Ansicht den zusammengebauten Verriegelungsdeckel gemäß 4, mit Blick auf die Innenseite des Deckels und
• 6 in perspektivischer Ansicht den zusammengebauten Verriegelungsdeckel gemäß 4, mit Blick auf die Außenseite des Deckels.

In the drawings, embodiments of the invention are shown. Show it:

• 1 schematically the side view of a camshaft adjuster, which is connected to a camshaft,
• 2 one too 1 alternative embodiment of the camshaft adjuster,
• 3 the front view of the camshaft adjuster in section A - B according to 1 , shown without ancillaries,
• 4 in exploded view, the two parts of a locking cover of the camshaft adjuster,
• 5 in a perspective view of the assembled locking lid according to 4 , facing the inside of the lid and
• 6 in a perspective view of the assembled locking lid according to 4 , facing the outside of the lid.

Detailed description of the drawings

In 1 and 2 is only very schematically a camshaft adjuster 1 represented, with which a camshaft 2 can be adjusted relative to the crankshaft with respect to the angle of rotation. Indicated is an inner rotor 3 and an outer rotor 4 of the camshaft adjuster 1 , where the inner rotor 3 relative to the outer rotor 4 As will be seen later, it can be rotated to move the camshaft between an "early" working position and a "late" working position. The camshaft adjuster 1 has a first sidewall 5 and a second side wall 6 on, with the second side wall 6 designed as a locking lid, which is required for the axial Verrieglung when the camshaft adjuster 1 especially for the start of the engine in a middle position between "early" and "late" to be locked.

Via a chain, not shown, an operative connection between the crankshaft of the internal combustion engine and a drive gear is produced, which is non-rotatably connected to the outer rotor 4 connected is. Alternatively, gear or timing belt drives can be used. An adjustment mechanism, not shown, provides a relative rotational position between the outer rotor 4 and inner rotor 3 ago. The inner rotor 3 is non-rotatably with the camshaft via a (not sketched) central screw 2 the internal combustion engine bolted.

The two 1 and 2 differ in that in the case of the solution according to the 1 the locking lid 6 at the of the camshaft 2 opposite side is arranged. Meanwhile, the locking lid 6 in the solution according to 2 at the camshaft 2 facing side of the camshaft adjuster 1 positioned.

The locking lid 6 of the camshaft adjuster 1 can therefore be located on the side facing the engine or facing away. Its axis is coaxial with the axis of the inner / outer rotor 3 . 4 or the camshaft 2 aligned.

In 3 is the known structure of a generic camshaft adjuster 1 to see. The outer rotor 4 has in the exemplary embodiment on five incorporated recesses, the hydraulic chambers 7 form. These are through the two side walls 5 . 6 (S. 1 and 2 ) limited.

In the inner rotor 3 in the exemplary embodiment, five grooves are incorporated, which in the present case extend in the radial direction and along the axial direction of the camshaft adjuster. In each groove is an element 8th plugged in the shape of a grand piano. The wing 8th extends in its assembled state radially to the outer radial boundary of the hydraulic chamber 7 , This will cause the hydraulic chamber 7 in two sub-chambers 9 and 10 each of which - which is not shown in detail - are in communication with hydraulic lines, via the hydraulic fluid in the sub-chambers 9 . 10 can be initiated. The wing 8th can in principle also be designed as a sealing strip or the like element, which has a subdivision of the hydraulic chamber 7 in two sub-chambers 9 . 10 can accomplish.

The locking of the camshaft adjuster 1 in a middle position between "early" and "late" is by two locking pins 11 and 12 accomplished in corresponding holes in the inner rotor 3 are used. The locking pins are movable by means not shown in the axial direction and act as a locking piston. In cooperation with the design of the Verrieglungsdeckels 6 may be blocking the relative rotation between inner rotor 3 and outer rotor 4 be made.

This is on the 4 to 6 referenced the locking lid 6 demonstrate.

The locking lid 6 consists of two disc-shaped parts 15 and 16 namely from a first part 15 , which acts as an outer part, and a second part 16 which is the inner part. The inner part 16 is therefore the interior of the camshaft adjuster 1 facing and in particular the locking pins 11 and 12 , To lock, ie to block the relative rotation between the inner rotor 3 and outer rotor 4 , the locking pins become 11 and 12 axially in the direction of the locking cover 6 shifted and reach into recesses 13 and 14 in the locking lid 6 a, s. 5 , which are formed as a backdrop, ie have a slightly elongated shape. It is essential that ever a recess 13 respectively. 14 in one part each 15 respectively. 16 of the locking lid 6 is introduced.

The outer part 15 of the locking lid 6 has penetrations or slugs, s. 4 that as a lead 17 are formed. Preferably, the projections 17 produced by a forming process.

The inner part 16 of the locking lid 6 has corresponding to the position of the projections 17 breakthroughs 18 , s. 4 , which are formed as a slot.

Be the two parts 15 and 16 mounted, ie the projections 17 through the breakthroughs 18 stuck, results from the formation of breakthroughs 18 as long holes the possibility of the two parts 15 . 16 to twist a certain angle relative to each other. This is used to adjust the locking clearance during assembly, which is the interaction of the locking pins 11 . 12 with the recesses 13 . 14 results.

So that the recess 13 in the outer part 15 of the locking lid 6 accessible to the corresponding locking pin, the inner part has 16 in this area a first recess 19 on.

Unless the recesses 13 . 14 are produced by a forming process and consequently at the recesses 13 . 14 facing away from the end of the parts 15 . 16 form corresponding bulges, however, an axially flat lid construction can be achieved, if for the bulge of the recess 14 in part 15 a second recess 20 is provided as it is 4 is apparent.

During assembly, proceed as follows:

The two parts 15 and 16 of the locking lid 6 are assembled before assembly so that the respective protruding elements of a part, in particular the projections 17 , engage in the recesses in the other part. The complete locking lid 6 gets on the outer rotor 4 placed and fixed with screws.

Before the exact positioning of the locking lid 6 becomes the camshaft adjuster 1 locked. Then the inner part 16 of the locking lid 6 twisted so that the desired locking clearance is set. The inner part 16 is held in this position.

Then the outer part 15 of the locking lid 6 twisted until the locking clearance is set. For this purpose, the passage openings of the screws in the inner rotor 3 or outer rotor 4 also formed as slots, which extend in the circumferential direction. Subsequently, the outer part 15 recorded. Then the screws are tightened; the inner part 16 of the locking lid 6 retains its position as it is between the outer rotor 4 and the outer part 15 of the locking lid 6 is clamped.

LIST OF REFERENCE NUMBERS

1

Camshaft adjustment device

2

camshaft

3

inner rotor

4

outer rotor

5

first sidewall

6

second side wall (locking cover)

7

hydraulic chamber

8th

Element (wing)

9

first compartment

10

second sub-chamber

11

locking pin

12

locking pin

13

Recess (backdrop)

14

Recess (backdrop)

15

first part of the locking cover (outer part)

16

second part of the locking cover (inner part)

17

head Start

18

breakthrough

19

first recess

20

second recess

Claims (14)

Device (1) for adjusting the camshaft of an internal combustion engine, which has a rotatably connected to a camshaft (2) inner rotor (3) which is rotatably adjustable relative to an outer rotor (4) drivingly connected to a crankshaft, wherein in the outer rotor (4) at least one hydraulic chamber (7) delimited by side walls (5, 6) is subdivided into two subchambers (9, 10) by an element (8) extending radially outwards from the internal rotor (3), and wherein the interlocking device Relative movement between the inner rotor (3) and outer rotor (4) has two corresponding axially inserted in corresponding holes of the inner rotor (3) locking pins (11, 12) are present, which can engage in two recesses (13, 14) in one of Locking lid trained side walls (6) are introduced, characterized in that the locking cover (6) consists of two parts (15, 16), wherein each of the parts ( 15, 16) each have a recess (13, 14) for engaging a respective locking pin (11, 12). Device (1) according to Claim 1 , characterized in that the two parts (15, 16) of the locking cover (6) are each disc-shaped and arranged concentrically with each other. Device (1) according to Claim 1 , characterized in that the recesses (13, 14) are formed like a backdrop. Device (1) according to Claim 1 , characterized in that the two parts (15, 16) of the locking cover (6) are formed so that they are rotatable in the circumferential direction relative to each other up to a predetermined angle of rotation. Device (1) according to Claim 4 , characterized in that one of the parts (15) of the locking cover (6) from the Grundkontor of the part (15) elevating projections (17) for passage through corresponding openings (18) in the other part (16) of the locking cover ( 6) are formed. Device (1) according to Claim 5 , characterized in that the projections (17) are produced by a forming process. Device (1) according to Claim 5 , characterized in that the projections (17) have a cylindrical or hollow cylindrical basic contour. Device (1) according to Claim 5 , characterized in that the openings (18) in the other part (16) of the locking cover (6) are designed as a slot. Device (1) according to Claim 5 , characterized in that a plurality of projections (17) and apertures (18) over the circumference of the parts (15, 16) of the locking cover (6) are arranged. Device (1) according to Claim 9 , characterized in that four, five or six projections (17) and apertures (18) are arranged equidistantly over the circumference of the parts (15, 16) of the locking cover (6). Device (1) according to Claim 1 , characterized in that in the locking pins (11, 12) facing part (16) of the locking cover (6) has a first recess (19) for exposing the in the of the locking pins (11, 12) facing away from the part (15) of the locking lid (6) introduced recess (13) is arranged. Device (1) according to Claim 1 , characterized in that the recesses (13, 14) in the locking cover (6) are made by milling. Device (1) according to Claim 1 , characterized in that the recesses (13, 14) in the locking cover (6) are made by forming. Device (1) according to Claim 13 characterized in that in the part (15) of the locking cover (6) remote from the locking pins (11, 12) there is a second recess (20) for the entry or passage of formed material of the part (16) facing the locking pins (11, 12). of the locking cover (6) is introduced.

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