Camshaft adjuster

Abstract

A hydraulic camshaft adjuster of the vane cell type, including a rotor and a stator and including a cover having fastening holes extending all the way through for accommodating fasteners. Via the fasteners the cover is fastened at an end face to the stator. The cover has a locking hole, into which a locking pin accommodated in the rotor can be displaced in an axial direction in order to lock the rotor in relation to the stator. The position of the locking pin in the rotor is pivoted about the axis of rotation by an angle in relation to a fastener when the camshaft adjuster is used as an exhaust adjuster, the position of the locking pin in the rotor is pivoted about the axis of rotation by an angle in relation to a fastener when the camshaft adjuster is used as an intake adjuster, and the position of the locking hole in the cover is pivoted about the axis of rotation by an angle in relation to the position of a fastening hole, wherein the rotor and the stator are coordinated with each other in such a way that the angles , , and are equal in magnitude and the pivoting directions of the angle and are oppositely directed.

Claims

1. A vane cell hydraulic camshaft adjuster comprising: a rotor and a stator rotatable relative to one another about a rotation axis of the camshaft adjuster; a cover having through fastening holes for accommodating fastening elements, the cover being alternatively fixable to the front side of the stator via the fastening elements in an outlet adjuster mode and in an inlet adjuster mode, the cover including a radially extending side surface facing axially toward the stator in the outlet adjuster mode and the radially extending side surface facing axially away from the stator in the inlet adjuster mode, the cover having a locking hole; and a locking pin accommodated in the rotor and displaceable in the axial direction being introducible into the locking hole in order to lock the rotor with respect to the stator, a position of the locking pin in the rotor being pivoted about the rotation axis by an angle in relation to one of the fastening elements when the camshaft adjuster is in the outlet adjuster mode, the position of the locking pin in the rotor being pivoted about the rotation axis by an angle a in relation to a fastening element when the camshaft adjuster in the inlet adjuster mode, and the position of the locking hole in the cover being pivoted about the rotation axis by an angle a in relation to the position of one of the fastening holes, the rotor and the stator being coordinated with one another in such a way that the angles , , and are equal in magnitude and pivot directions of the angles and are oppositely directed.

2. The hydraulic camshaft adjuster as recited in claim 1 wherein the cover has a disk design with two flat side faces oriented orthogonally with respect to the rotation and both designed for a sealing contact with the stator or rotor, the radially extending surface forming one of the flat side faces.

3. The hydraulic camshaft adjuster as recited in claim 2 wherein the disk-design is ring-shaped.

4. The hydraulic camshaft adjuster as recited in claim 1 wherein the cover includes a further radially extending side surface opposite of the radially extending side surface, the radially extending side surface of the cover resting against the stator or the rotor, sealing off vane cells formed between the stator and the rotor in the outlet adjuster mode, the further radially extending side surface of the cover resting against the stator or the rotor, sealing off vane cells formed between the stator and the rotor in the inlet adjuster mode.

5. The hydraulic camshaft adjuster as recited in claim 1 wherein in the outlet adjuster mode, the rotor is adjustable with respect to the stator from a locking position in the clockwise direction, and in the inlet adjuster mode, the rotor is adjustable with respect to the stator from the locking position in the counterclockwise direction.

6. The hydraulic camshaft adjuster as recited in claim 1 wherein the locking hole is a through hole.

7. The hydraulic camshaft adjuster as recited in claim 1 wherein the fastening elements and the fastening holes of the stator in a joining plane between the cover and the stator are provided or arranged axially symmetrically with respect to a vertical axis orthogonally intersecting the rotation axis.

8. The hydraulic camshaft adjuster as recited in claim 1 further comprising a bushing closing the locking hole in a sealing manner and situated in the locking hole.

9. The hydraulic camshaft adjuster as recited in claim 8 wherein the bushing has a U-shaped cross section with a front wall and a circumferential wall adjoining an outer edge of the front wall.

10. The hydraulic camshaft adjuster as recited in claim 1 wherein the fastening elements are screws.

11. The hydraulic camshaft adjuster as recited in claim 10 wherein the screws engage with threads in the fastening holes.

12. The hydraulic camshaft adjuster as recited in claim 1 wherein first and second position markings are provided on the cover and on the stator.

13. The hydraulic camshaft adjuster as recited in claim 1 wherein the fastening holes are through holes.

14. The hydraulic camshaft adjuster as recited in claim 1 wherein the rotor includes a plurality of vanes, the locking pin passing through one of the vanes.

15. The hydraulic camshaft adjuster as recited in claim 1 wherein an outer circumference of the cover includes a first cover groove and a second cover groove circumferentially spaced from the first cover groove, an outer circumference of the stator including a first stator groove and a second stator groove, the first cover groove being aligned with the first stator groove in the outlet adjuster mode and the second cover groove being aligned with the second stator groove in the inlet adjuster mode.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) The present invention is explained in greater detail below with reference to exemplary embodiments, with the aid of drawings.

(2) FIG. 1 shows a top view onto one specific embodiment of a camshaft adjuster according to the present invention, as an outlet adjuster without a cover;

(3) FIG. 2 shows a top view onto one specific embodiment of a camshaft adjuster according to the present invention, as an inlet adjuster without a cover;

(4) FIG. 3 shows a top view onto one specific embodiment of a camshaft adjuster according to the present invention, as an outlet adjuster with a cover;

(5) FIG. 4 shows a top view onto one specific embodiment of a camshaft adjuster according to the present invention, as an inlet adjuster with a cover;

(6) FIG. 5 shows a perspective view of the camshaft adjuster of FIG. 3;

(7) FIG. 6 shows a perspective view of the camshaft adjuster of FIG. 4;

(8) FIG. 7 shows a perspective view of a cover or locking cover for a camshaft adjuster according to the present invention;

(9) FIG. 8 shows a front view of the cover of FIG. 7;

(10) FIG. 9 shows a rear view of the cover of FIG. 7; and

(11) FIG. 10 shows another specific embodiment of the cover.

DETAILED DESCRIPTION

(12) The figures are merely schematic, and are used only for an understanding of the present invention. Identical elements are provided with the same reference numerals. Details of the various exemplary embodiments may also be combined and/or exchanged with one another.

(13) FIGS. 1, 3, and 5 show a camshaft adjuster 1 according to the present invention as an outlet adjuster. FIGS. 2, 4, and 6 show a camshaft adjuster 1 according to the present invention as an inlet adjuster. In both specific embodiments, camshaft adjuster 1 is used for adjusting the rotation angle of a camshaft, not shown, with respect to the crankshaft of an internal combustion engine. The gas exchange valves of the internal combustion engine are actuated with the aid of the camshaft. The optimum valve timing changes with the engine speed. For the intake valves, the timing is retarded with increasing engine speed, and for the exhaust valves it is advanced. For engines having separate camshafts for the intake valves and exhaust valves, there is the option of easily achieving the desired speed-dependent adaptation of the timing by appropriately rotating the camshafts.

(14) Camshaft adjuster 1, as an inlet adjuster and as an outlet adjuster, includes a stator 2 and a rotor 3 which are concentrically rotatable about a rotation axis 4 of camshaft adjuster 1, and rotatable relative to one another about rotation axis 4. Vane cells 5, 6, 7, 8, 9 are formed between rotor 2 and stator 3, and are to be acted on by pressure oil in order to effectuate a relative rotation of rotor 2 and stator 3.

(15) A cover 10 is fastened on the front side of stator 3. The cover is used as a seal for vane cells 5, 6, 7, 8, 9 that are formed between rotor 2 and stator 3. Cover 10 is essentially ring-shaped, and is provided with a front surface 11, a rear surface 12, a circumferential outer surface 13, and a central recess 14. Cover 10 has five fastening holes 15, 16, 17, 18, 19, each provided with an internal thread, and a locking hole 20. Fastening holes 15, 16, 17, 18, 19 are designed as through holes, and are each spaced apart from one another by the same angle . Locking hole 20 is likewise designed as a through hole. The central axes of fastening holes 15, 16, 17, 18, 19 and of locking hole 20 are in parallel to rotation axis 4.

(16) In particular, FIGS. 1 through 4 show that the side of stator 3 facing cover 10, i.e., the joining plane between cover 10 and stator 3, is oriented axially symmetrically with respect to vertical axis 31, which is oriented orthogonally with respect to rotation axis 4, indicated in the figures.

(17) As shown in FIGS. 1 and 3, a stator segment 21, 22, 23, 24, 25 is situated in each case between two adjacent vane cells 5, 6, 7, 8, 9. A fastening hole 26, 27, 28, 29, 30 is formed in each stator segment 21, 22, 23, 24, 25. Fastening holes 26, 27, 28, 29, 30 are each spaced apart from one another by the same angle . Rotor 2 includes five rotor vanes 32, 33, 34, 35, 36 which are each spaced apart from one another by angle . A locking pin receptacle 37 in which a locking pin 38 is accommodated so that it is displaceable in parallel to rotation axis 4 is formed in rotor vane 32 situated in vane cell 9.

(18) FIG. 1 illustrates camshaft adjuster 1 as an outlet adjuster in its locking position with respect to stator 3. In this locking position, locking pin receptacle 37 is pivoted by an angle relative to fastening hole 30. FIG. 2 illustrates camshaft adjuster 1 as an inlet adjuster in its locking position with respect to stator 3. In this locking position, locking pin receptacle 37 is pivoted by an angle relative to fastening hole 30. A comparison of FIGS. 1 and 2 shows that angles and are equal in magnitude but have opposite directions, in particular with respect to angle depicted in these figures.

(19) Locking hole 20 in cover 10 is spaced apart from fastening hole 19 by an angle . Angle has the same magnitude as angles and . FIGS. 8 and 9 show cover 10, once in the orientation for the outlet adjuster (FIGS. 5 and 8), in which it rests with its rear surface 12 against stator 3 and rotor 2, and once in the orientation for the inlet adjuster (FIGS. 6 and 9), in which it rests with its front surface 11 against stator 3 and rotor 2. It is apparent that FIGS. 8 and 9 are axially symmetrical with respect to transverse axis 39, which is orthogonal with respect to vertical axis 31. In other words, cover 10 may be brought from the orientation for the outlet adjuster, illustrated in FIGS. 3 and 8, into the orientation for the inlet adjuster, illustrated in FIGS. 4 and 9, by pivoting it by 180 about vertical axis 31 and by 90 about rotation axis 4.

(20) A comparison of FIG. 1 with FIG. 3, and of FIG. 2 with FIG. 4, shows that, due to such an arrangement on the inlet adjuster or outlet adjuster, locking hole 20 of cover 10 is to be brought into a position which overlaps with locking pin receptacle 37. In other words, a single cover 10 may be utilized as an inlet adjuster as well as an outlet adjuster due to the above-described geometric configuration of rotor 2, stator 3, and cover 10 by an appropriate orientation for a camshaft adjuster 1. Locking pin 38, which is displaceably accommodated in locking pin receptacle 37, may therefore engage with locking hole 20 in cover 10 when the locking pin moves out from rotor 2 in the direction of cover 10, thus preventing rotation of rotor 2 relative to cover 10, and thus relative to stator 3 on which cover 10 is fixed.

(21) Locking hole 20 is sealed off with the aid of a sleeve 40 which is pressed into locking hole 20. This sleeve 40 is illustrated in a perspective view in FIG. 7, and has a front wall 41, corresponding to the shape and size of locking hole 20, and a circumferential wall 42 situated at the outer circumference of the sleeve. In other words, sleeve 40 has an essentially U-shaped cross section (longitudinal section). In order for cover 10 to be usable for an inlet adjuster or an outlet adjuster by the above-described rotation about vertical axis 31, sleeve 40 must be inserted into locking hole 20, either with front wall 41 facing rear side 12 of cover 10, or with front wall 41 facing front side 11 of cover 10. This is schematically depicted in FIG. 7. Sleeve 40 may be inserted from front side 11 or from rear side 12, depending on the application.

(22) In order to facilitate installation of cover 10 according to the poka-yoke principle, based on the particular application, and to insure correct installation of cover 10, the cover is provided with two grooves 43, 44 on its outer surface 13. Corresponding grooves 45, 46 are formed at the outer diameter of stator 3. FIGS. 5 and 6 show that when cover 10 is correctly installed as an outlet adjuster, two of the grooves (groove 43 and groove 45) are aligned with one another, and when the cover is correctly installed as an inlet adjuster, the other grooves (groove 44 and groove 46) are aligned with one another. In this way, during the installation of cover 10 it may be verified whether locking hole 20, which is closed with the aid of sleeve 40, is situated in the correct position in alignment with locking pin receptacle 37 and locking pin 38.

(23) FIG. 10 shows another specific embodiment of cover 10 in which the cover has an additional locking hole 52. Such a cover 10 may be used on various rotor/stator combinations in which the locations of the particular locking positions are different.

LIST OF REFERENCE NUMERALS

(24) 1 camshaft adjuster 2 rotor 3 stator 4 rotation axis/longitudinal axis 5-9 vane cell 10 cover 11 front surface 12 rear surface 13 outer surface 14 central recess 15-19 fastening hole 20 locking hole 21-25 stator segment 26-30 fastening hole 31 vertical axis 32-36 rotor vane 37 locking pin receptacle 38 locking pin 39 transverse axis 40 sleeve 41 front wall 42 circumferential wall 43-46 groove 47-51 screws