DE102008058110B4 - Phaser - Google Patents

Abstract

Camshaft adjuster with an at least partially hollow camshaft (39), the camshaft adjuster being a vane-type camshaft adjuster (38) with a stator (1) which can be rotated relative to the camshaft (39) against the spring force of a spring, this spring being at least partially radially within one Rotor hub (7) is arranged, the spring being connected in a rotationally fixed manner on the one hand to the stator (1) and on the other hand being connected in a rotationally fixed manner to the camshaft (39).

Description

The invention relates to a camshaft adjuster according to claim 1.

The DE 10 2005 023 006 A1 shows an electric camshaft adjuster for a built or hollow camshaft. The phaser is designed as a planetary gear, the planet carrier is connected to one end of a torsion spring, the other end is fixed within the hollow camshaft.

From the DE 103 33 850 B4 , of the DE 101 60 246 C1 , of the DE 101 25 498 A1 and the not pre-published DE 10 2008 029 692 A1 are more built or hollow camshafts are known which have a camshaft adjuster.

From the DE 601 27 023 T2 is a Flügelzellennockenwellenwellensteller with a stator known. This stator is rotatable against a spring force of a spring relative to the camshaft.

From the WO 2008/0150062 A2 is known a Flügelzellennockenwellenwellenversteller with a coil spring, which tends to keep a rotor of the Flügelzellennockenwellenverstellers in a certain angular position relative to a stator of the Flügelzellnockenwellenverstellers.

The object of the invention is to build a short axial camshaft adjuster.

This object is achieved with the features of claim 1.

According to an advantage of the invention, a vane-type camshaft phaser is used. This Flügelzellennockenwellenversteller builds axially very short, which benefits the tight space conditions of both transversely and longitudinally installed drive trains.

According to a further advantage of the invention, a spring disposed at least partially within the camshaft holds the rotor in a certain angular position relative to the stator. This region of the camshaft, in which at least part of the spring is arranged, can also be a tubular or drilled projection on the camshaft. This approach can also have a centering function.

In a particularly advantageous embodiment, however, the camshaft itself is designed as a hollow camshaft. The spring may for example be designed as a torsion bar.

To connect the spring with the camshaft, an insert can be inserted into the hollow camshaft and connected to it in a torque-proof manner. This insert then has a connection with the spring. The spring may be connected at the other end in particular with a cover of the camshaft adjuster.

In the camshaft associated with the outlet, the spring can be used to bring the rotor into an early exhaust camshaft position that is necessary for starting the engine. In general, both camshafts - d. H. Inlet and outlet - are compensated by a bias of the spring in a torque direction, the alternating torques of the camshaft, which are different degrees of effectiveness in the two directions of torque of the camshaft. These alternating moments are caused by the valve spring forces on the gas exchange valves and are highly dependent on the number of cylinders. The alternating moments are all the more irregular, the less cylinders the internal combustion engine has. In this case, the spring can be twisted in a particularly advantageous manner in the rest position in the torque direction "early", since the adjustment of the Flügelzellennockenwellenverstellers in the torque direction "late" due to the supporting effect by the alternating moments anyway faster. Thus, it is achieved by means of the spring that the adjustment in "early" as fast as in "late".

To supply the pressure chambers of the camshaft adjuster with pressure medium - in particular oil - channels can be provided in a particularly advantageous embodiment of the invention, which form on sleeves which are inserted into the hollow cam shaft radially outside the spring.

Further advantages of the invention will become apparent from the other claims, the description and the drawings.

The invention is explained in more detail with reference to an embodiment.

Show

1 a Flügelzellennockenwellenwellenversteller with a built camshaft in a longitudinal section along its longitudinal axis and

2 the camshaft adjuster off 1 in a front view.

1 shows a built camshaft 39 with an associated vane-cell camshaft adjuster 38 , The camshaft 39 is here as a built camshaft 39 executed. In such a built camshaft 39 are the cams 25 . 26 as a single body on the tubular camshaft 39 shrunk and frictionally connected by means of a micro-toothing. With the vane-cell camshaft adjuster 38 During operation of an internal combustion engine, the angular position between the crankshaft and the camshaft 39 changed. By turning the camshaft 39 The opening and closing times of the gas exchange valves are shifted so that the internal combustion engine brings its optimum performance at the respective speed. The vane-cell camshaft adjuster 38 allows a stepless adjustment of the camshaft 39 relative to the crankshaft. The operation of a Flügelzellnockenwellenverstellers 38 For example, the DE 10 2006 019 435 A1 be removed, which in this regard should also be considered as included in this patent application. In this case, the Flügelzellennockenwellenwellenversteller includes 38 a cylindrical stator 1 , which rotates with a gear 2 connected is. In the embodiment, the gear 2 a sprocket over which a chain, not shown, is guided. The gear 2 but may also be a toothed belt, over which a drive belt is guided as a drive element. Alternatively, the gear 2 mesh with another gear as a drive element. About this drive element and the gear 2 is the stator 1 drivingly connected to the crankshaft in a known manner.

The stator 1 and the gear 2 may alternatively be integrally formed with each other when the other side of the stator 1 according to the embodiment 1 is openable. This can be the stator 1 and the gear 2 made of metallic material or hard plastic. Suitable metallic materials include sintered metals, steel sheets and aluminum. As plastics in particular resin-bound mineral flours in question, which may also have fiber reinforcements. Such plastics have coefficients of thermal expansion approachable to the thermal expansion coefficient of metallic material. The stator 1 comprises a cylindrical stator base body three , projecting webs on the inside radially inwardly at equal intervals. Between adjacent bridges pressure chambers 9 . 10 formed, in which, controlled by a non-illustrated 4/3-way valve, pressure medium is introduced. Between adjacent lands projecting wings radially outward from a cylindrical rotor hub 7 stand out of a rotor. These wings divide the pressure spaces between the webs in two pressure chambers 9 and 10 ,

The webs lie with their radially inner end faces sealingly on the outer circumferential surface 6 the rotor hub 7 at. The wings in turn lie with their radially outer end faces sealingly on the cylindrical inner wall 5 of the stator base body three at.

The rotor 8th is rotatably with the camshaft, not shown 39 connected. To the angular position between the camshaft 39 and to change the crankshaft becomes the rotor 8th with the rotor hub 7 relative to the stator 1 twisted. For this purpose, depending on the desired direction of rotation, the pressure medium in the pressure chambers 9 or 10 pressurized while each other's pressure chambers 10 or 9 be relieved to the tank.

The stator 1 is between a stator cover 4 and the gear 2 by means of screws 37 axially braced. Thus, the stator 1 firmly with the gear 2 screwed. The side surfaces 33 . 34 . 35 . 36 the webs and the wing 6 lie on the one hand close to the gear 2 and on the other hand, close to the stator lid 4 at. This stator cover 4 and the gear 2 also limit the pressure chambers 5 between the wings 4 in the axial direction. Thus with switched off internal combustion engine - ie with unloaded Flügelzellennockenwellenversteller 38 - the rotor 8th takes the necessary for the engine start early exhaust camshaft position, the rotor 8th by a torsion bar spring 12 turned into a starting position. In this initial position there is a lock between the rotor 8th and the stator 1 for example, by a spring-loaded locking bolt 21 , This one is in one of the wings 6 housed, as exemplified in the said DE 10 2006 019 435 A1 is apparent. With pressure drop in the pressure chambers 9 . 10 will this locking bolt 21 moved by the spring force of a helical compression spring not shown in a locking position, in which this in a locking opening of the stator 1 intervenes. When starting the engine, the locking bolt is activated 21 loaded by the pressure medium against the spring force and pushed back, so that the rotor 8th from the stator 1 is unlocked and the Flügelzellennockenwellenwellenversteller can get into its control position.

The torsion bar spring 12 is at both ends with fasteners 32 . 31 provided, which are designed as a square. The front square is in a square-shaped recess 30 of the stator cover 4 used rotatably. The rear square is, however, rotationally fixed in a square-shaped recess 29 an insert 14 used. This use 14 is on the the camshaft adjuster 38 opposite end of the hollow camshaft 39 used in this rotation. Will now be pressure on one of the directions of rotation or the opposite direction of rotation associated pressure chambers 9 respectively. 10 exercised, then the stator 1 against the rotor 8th twisted. It is about the length of the torsion bar 12 this torsion bar 12 against the camshaft 39 twisted. Because the camshaft 39 opposite the torsion bar spring 12 has a relatively large diameter, twisting the camshaft 39 hardly in relation to the torsion bar 12 ,

The one of the adjustment associated pressure chambers 9 are over a rear radial bore 40 in the rotor hub 7 pressurizable. This rear radial bore 40 The hydraulic fluid is for adjustment of a front camshaft bearing bore 22 in the area of the camshaft bearing 21 made available. In this case, the hydraulic fluid by means of an outer sleeve 20 from the front camshaft bearing bore 22 over a canal 41 to the rear radial bore 40 directed. This outer sleeve 20 is at its two ends by means of an annular peripheral shoulder opposite the inner wall 19 the camshaft 39 sealed. Radial within this outer sleeve 20 extends an inner sleeve 18 , which over the two ends of the outer sleeve 20 protrudes and with its two ends also close to the inner wall 19 the camshaft 39 is applied. So this inner sleeve 18 the pressure medium directly from a rear camshaft bearing bore 17 over a canal 15 to a front radial bore 16 guide, which the other adjustment direction associated pressure chambers 10 can put pressure on.

The torsion bar spring 12 does not have to be over the entire length of the camshaft 39 extend. The use 14 for receiving the torsion bar spring 12 can also be in a range between the two ends of the camshaft 39 be provided. The use 14 can from one or the other end of the camshaft 39 in the camshaft 39 be plugged. It does not have to be used 14 be provided. Thus, the camshaft, for example, be designed as a hollow shaft, which is welded to a solid shaft - in particular reibverschweißt - is. In this case, the solid shaft in the contact area between the hollow shaft and the solid shaft is designed with a connection receptacle for the connecting element of the torsion bar. Instead of using a hollow shaft, it is also possible to perform the camshaft entirely as a solid shaft with a central bore or to clamp a hollow centering adapter with the camshaft. In that case, the connection receptacle is incorporated in the end of the camshaft. This connection does not have to be square. There are also other forms of connection possible, which include in particular the classic shaft-hub connections, such as the polygonal profiles.

To safely exclude vibrations in the natural frequency, which would lead to the striking of the rotor against the stator, suitable damping means may be provided. These may be provided in the radial gap between the torsion bar spring and the hollow shaft. These may be, in particular friction body, which are rotationally fixed to the torsion bar spring and rub against the inner wall of the camshaft. The damping means can also be provided in the camshaft adjuster itself. In this case, for example, the shape of the wings and the webs may be designed such that before the stop of the wing to the webs, the hydraulic fluid is sheared to operate the camshaft adjuster. It is also possible to put a hydraulic damping in the hollow camshaft. For example, the interior may be filled within the camshaft with a fluid, wherein the spring is provided in the interior of the camshaft with wings that shear this fluid during twisting.

The spring must therefore not be designed as a round torsion bar spring with a linear spring rate. The spring may, for example, also have a progressive spring detection, which prevents the rotor comes to stop the stator.

Instead of the torsion spring also another spring may be provided within the camshaft. For example, coil springs are possible with correspondingly rigid dimensions.

The described embodiments are only exemplary embodiments. A combination of the described features for different embodiments is also possible. Further, in particular not described features of the device parts belonging to the invention are to be taken from the geometries of the device parts shown in the drawings.

Claims (9)

Camshaft adjuster with an at least partially hollow camshaft ( 39 ), wherein the camshaft phaser a Flügelzellennockenwellenwellenversteller ( 38 ) with a stator ( 1 ), which is against a spring force of a spring with respect to the camshaft ( 39 ) is rotatable, said spring at least partially radially within a rotor hub ( 7 ) is arranged, wherein the spring on the one hand with the stator ( 1 ) is rotatably connected and on the other hand rotationally fixed with the camshaft ( 39 ) connected is. Camshaft adjuster according to claim 1, characterized in that the spring from one end of the camshaft ( 39 ) to the other end of the camshaft ( 39 ). Camshaft adjuster according to one of the preceding claims, characterized in that the camshaft ( 39 ) a built camshaft ( 39 ). Camshaft adjuster according to one of the preceding claims, characterized in that for the rotationally fixed connection between the spring and the camshaft ( 39 ) an insert ( 14 ) is provided, the non-rotatably with the camshaft ( 39 ) and a recess ( 29 ) for receiving the spring. Camshaft adjuster according to claim 1, characterized in that the connection between the spring and the stator ( 1 ) and / or the camshaft ( 39 ) is produced by means of a square connection. Camshaft adjuster according to one of the preceding claims, characterized in that in a hollow region of the camshaft ( 39 ) radially inside the rotor hub ( 7 ) protrudes a sleeve, which pressure medium for the adjustment of the Flügelzellennockenwellenwellenverstellers ( 38 ) in the one direction of rotation associated pressure chambers ( 9 ) and close to the inner wall ( 19 ) of the camshaft ( 39 ) is present. Camshaft adjuster according to claim 6, characterized in that the sleeve is an outer sleeve ( 20 ), within which an inner sleeve ( 18 ), which over the two ends of the outer sleeve ( 20 ) protrudes and with its two ends also close to the inner wall ( 19 ) of the camshaft ( 39 ) is applied, wherein between this inner sleeve ( 18 ) and the outer sleeve ( 20 ) a channel ( 15 ), the pressure medium for adjusting the Flügelzellennockenwellenwellenverstellers ( 38 ) in the other direction of rotation associated pressure chambers ( 10 ). Camshaft adjuster according to claim 6 or 7, characterized in that the camshaft adjuster ( 38 ) the pressure medium for adjustment of the camshaft bearing ( 21 ). Camshaft adjuster according to one of the preceding claims, characterized in that the spring is a torsion spring ( 12 ).

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