Camshaft adjuster

Abstract

A hydraulic, vane-type camshaft adjuster (1) having a rotor (2) and a stator (3) mounted such as to be rotatable relative to each other and to form vanes, wherein, for the radial positioning of the rotor (2) relative to the stator (3), a return spring (5) is or can be secured at one end to the rotor (2) and at the other end to the stator (3), and a spring contact component (15), especially in the shape of a ring, for centering the return spring (5) and/or limiting the radial position thereof, is fixed to the rotor (2) in at least two points.

Claims

1. A hydraulic camshaft adjuster comprising: a rotor; a stator mounted in such a way that the rotor and stator are rotatable relative to one another and form vane cells, a return spring for radially positioning the rotor relative to the stator being fixable to the rotor on the one hand and to the stator on the other hand, a spring contact component for centering the return spring or limiting a return spring radial position, the spring contact component being fixed to the rotor at two or more points by at least two fasteners, wherein a first end of the return spring engages with and/or encloses one of the at least two fasteners.

2. The hydraulic camshaft adjuster as recited in claim 1 wherein the spring contact component has a through central opening.

3. The hydraulic camshaft adjuster as recited in claim 1 wherein the at least two fasteners are bolts situated on the rotor.

4. The hydraulic camshaft adjuster as recited in claim 1 wherein the spring contact component has at least one recess for angular positioning of the spring contact component relative to the rotor.

5. The hydraulic camshaft adjuster as recited in claim 1 wherein the spring contact component has a clearance with which one end of the return spring designed as a bearing section engages, or with which the spring contact component is supported on the rotor in the axial direction.

6. The hydraulic camshaft adjuster as recited in claim 1 wherein the return spring is situated radially outside the spring contact component, and rests, at least in sections, against a radially outwardly directed surface of the spring contact component in a circumferential direction.

7. The hydraulic camshaft adjuster as recited in claim 1 wherein the spring contact component includes at least one detent projection protruding radially into a central opening of the spring contact component, and a trigger wheel is situated on the hydraulic camshaft adjuster, passing through the central opening with a flange section, the at least one detent projection axially fixing the trigger wheel.

8. The hydraulic camshaft adjuster as recited in claim 7 wherein the trigger wheel has a circumferential groove, introduced in the radial direction, with which the at least one detent projection engages.

9. The hydraulic camshaft adjuster as recited in claim 7 wherein the trigger wheel is secured against rotation with an aid of a central screw passing through the central opening.

10. The hydraulic camshaft adjuster as recited in claim 9 wherein the trigger wheel is clamped between the spring contact component and the central screw.

11. The hydraulic camshaft adjuster as recited in claim 1 wherein a material of the spring contact component is plastic or metal.

12. The hydraulic camshaft adjuster as recited in claim 1 wherein the spring contact component includes projections which protrude from a plane of the spring contact component in a same axial direction, the projections each corresponding to a position of one of the at least two fasteners.

13. The hydraulic camshaft adjuster as recited in claim 1 wherein the spring contact component includes through holes formed in the projections, each of the at least two fasteners passing through one of the through holes.

14. A hydraulic camshaft adjuster comprising: a rotor; a stator mounted in such a way that the rotor and stator are rotatable relative to one another and form vane cells, a return spring for radially positioning the rotor relative to the stator being fixable to the rotor on the one hand and to the stator on the other hand, a spring contact component for centering the return spring or limiting a return spring radial position being fixed to the rotor at two or more points, wherein the spring contact component includes at least one detent projection protruding radially into a central opening of the spring contact component, and a trigger wheel is situated on the hydraulic camshaft adjuster, passing through the central opening with a flange section, the at least one detent projection axially fixing the trigger wheel.

15. The hydraulic camshaft adjuster as recited in claim 14 wherein the trigger wheel has a circumferential groove, introduced in a radial direction, with which the at least one detent projection engages.

16. The hydraulic camshaft adjuster as recited in claim 14 wherein the trigger wheel is secured against rotation with an aid of a central screw passing through the central opening.

17. The hydraulic camshaft adjuster as recited in claim 16 wherein the trigger wheel is clamped between the spring contact component and the central screw.

18. A hydraulic camshaft adjuster comprising: a rotor; a stator mounted in such a way that the rotor and stator are rotatable relative to one another and form vane cells, a return spring for radially positioning the rotor relative to the stator being fixable to the rotor on the one hand and to the stator on the other hand, a spring contact component for centering the return spring or limiting a return spring radial position, the spring contact component being fixed to the rotor at two or more points by at least two fasteners, wherein the spring contact component includes projections which protrude from a plane of the spring contact component in a same axial direction, the projections each corresponding to a position of one of the at least two fasteners.

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 the drawings.

(2) FIG. 1 shows a perspective schematic view of one specific embodiment of a camshaft adjuster according to the present invention;

(3) FIG. 2 shows the camshaft adjuster of FIG. 1 in a top view;

(4) FIG. 3 shows the camshaft adjuster of FIGS. 1 and 2 in a perspective view together with a spring contact component;

(5) FIG. 4 shows the camshaft adjuster of FIGS. 1 through 3 in a top view together with a spring contact component;

(6) FIGS. 5A, 5B show the spring contact component of FIGS. 3 and 4 in perspective views;

(7) FIGS. 6A, 6B show the spring contact component of FIGS. 3 through 5 in top views from different directions;

(8) FIG. 7 shows the spring contact component of FIGS. 3 through 6 in a side view;

(9) FIG. 8 shows a top view of another specific embodiment of a camshaft adjuster according to the present invention;

(10) FIG. 9 shows a sectional view along line IX-IX in FIG. 8;

(11) FIG. 10 shows a sectional view along line X-X in FIG. 8;

(12) FIG. 11 shows an enlarged detail of FIG. 8;

(13) FIG. 12 shows a perspective view of the camshaft adjuster of FIG. 8;

(14) FIG. 13 shows a top view of the camshaft adjuster of FIG. 8 together with a trigger wheel;

(15) FIG. 14 shows a sectional view along line IX-IX in FIG. 13;

(16) FIG. 15 shows a sectional view along line X-X in FIG. 13;

(17) FIG. 16 shows an enlarged detail of FIG. 13;

(18) FIG. 17 shows a perspective view of the camshaft adjuster of FIG. 13;

(19) FIGS. 18A, 18B show the spring contact component of FIGS. 8 through 17 in perspective views;

(20) FIGS. 19A, 19B shows the spring contact component of FIGS. 8 through 17 in top views from different directions;

(21) FIG. 20 shows the spring contact component of FIGS. 8 through 17 in a sectional view;

(22) FIG. 21 shows an enlarged detail from FIG. 18A;

(23) FIGS. 22A, 22B show another specific embodiment of a spring contact component in perspective views;

(24) FIG. 23 shows the spring contact component of FIGS. 22A and 22B in a top view;

(25) FIG. 24 shows the spring contact component of FIGS. 22 and 23 in a sectional view;

(26) FIG. 25 shows an enlarged detail from FIG. 23; and

(27) FIG. 26 shows a trigger wheel in a perspective view.

DETAILED DESCRIPTION

(28) 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.

(29) FIGS. 1 through 4 show a camshaft adjuster 1 in a first specific embodiment, which 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. Camshaft adjuster 1 according to the present invention is used for this purpose.

(30) Camshaft adjuster 1 includes a stator 2 and a rotor 3 which are concentrically rotatable about a longitudinal axis 4 of camshaft adjuster 1, and rotatable relative to one another about longitudinal axis 4. Vane cells, not illustrated in the figures, are situated between rotor 2 and stator 3, and are to be acted on by a fluid, for example a liquid such as pressure oil, in order to effectuate a relative rotation of rotor 2 and stator 3.

(31) Camshaft adjuster 1 also includes a return spring 5 in the form of a coil spring. The return spring is fixed to rotor 2 at a first, radially inner end 6 and fixed to stator 3 at a second, radially outer end 7, and pretensions rotor 2 and stator 3 with respect to one another in the rotation direction. In this way, after an adjustment, rotor 2 and stator 3 may be returned to their original relative position with the aid of oil which is introduced into the vane cells in the event of a drop in the oil pressure.

(32) A cover 8 is fastened on the front side of stator 3 with the aid of screw connections 9. The cover is used as a seal for the vane cells formed between rotor 2 and stator 3. A spring retaining bolt 10 is pressed into the front side of cover 8 or stator 3 facing axially away from rotor 2 and stator 3. The spring retaining bolt may also be pressed into stator 3. The spring retaining bolt is enclosed by second end 7 of return spring 5, and fixes this end relative to stator 3. In addition, a spring guide bolt 11, which together with spring retaining bolt 10 fixes radially outer end 7 of return spring 5 in position in the radial direction, is pressed into the mentioned front side of cover 8. Three spring bolts 12, 13, 14 are pressed into rotor 2. The axes of spring bolts 12, 13, 14 of spring guide bolt 11 and of spring retaining bolt 10 are situated in parallel to and at a radial distance from longitudinal axis 4 of camshaft adjuster 1. The angle between spring bolts 12 and 13 and between spring bolts 13 and 14 is approximately 90 in each case, while the angle between spring bolts 12 and 14 is approximately 180. Spring bolt 14 is enclosed by first end 6 of return spring 4, and fixes this end relative to rotor 2.

(33) Spring bolts 12, 13, 14 are used to fix in position and retain a spring contact component in the form of a spring contact ring 15. In the specific embodiment installed in camshaft adjuster 1 according to FIGS. 1 through 4, the spring contact ring is individually illustrated in various views in FIGS. 5A, 5B, 6A, 6B, and 6C. Spring contact ring 15 has an essentially ring-shaped design with a central opening 16. The spring contact ring has projections 17, 18, 19 which protrude from the plane of the ring in the same axial direction, corresponding to the positions of spring bolts 12, 13, 14. In the area of these projections 17, 18, 19, spring contact ring 15 is provided with recesses 20, 21, 22 in the plane of the ring, which are used to accommodate spring bolts 12, 13, 14. Through holes 23, 24, 25 are introduced into projections 17, 18, 19 in the axial direction, corresponding to the positions of spring bolts 12, 13, 14. As is apparent in FIG. 1, the end faces of projections 17, 18, 19 on the rotor side form stop surfaces which contact and support spring contact ring 15 on rotor 2 in the axial direction.

(34) As is apparent in particular in FIG. 6A, recesses 20 and 21 have approximately the width of through holes 23 and 24 and pass through spring contact ring 15 only partially in the radial direction; i.e., they are designed as radially inwardly closed blind recesses. In addition, recess 22 has the same design as its assigned through hole 25, and protrudes completely through spring contact ring 15 in the radial direction. Laterally adjacent to through hole 25 in the circumferential direction, a free space is formed in which first end 6 of return spring 5 engages with and encloses spring bolt 14.

(35) Spring contact ring 15 is pressed onto spring bolt 14 with the aid of through hole 25, so that the spring contact ring is fixed on rotor 2 to secure the spring bolt against coming loose or being lost. Spring bolts 12 and 13 engage in corresponding through holes 23, 24 with an exact fit, so that spring contact ring 15 is supported at a defined angle with respect to rotor 2.

(36) As shown in particular in FIGS. 3 and 4, spring contact ring 15 is situated radially within return spring 5. Radially outer circumferential surface 26 of the spring contact ring forms a radially outwardly facing contact surface for return spring 5. The radially inner side of the inner winding of return spring 5 rests against the contact surface in an angular range of approximately 200 to 215 in the circumferential direction. The position of return spring 5 with respect to rotor 2, and thus with respect to stator 3, is clearly defined via spring contact ring 15. In addition, return spring 5 is inwardly supported and relaxed over virtually its entire circumference.

(37) FIGS. 8 through 17 show another specific embodiment of a camshaft adjuster 1 according to the present invention, in which a trigger wheel 27 is provided on camshaft adjuster 1. In FIGS. 8 through 12, camshaft adjuster 1 is illustrated without an installed trigger wheel 27, and in FIGS. 13 through 17 is illustrated with an installed trigger wheel 27. With regard to the description of rotor 2, stator 3, return spring 5, cover 8, and spring bolts 10, 11, 12, 13, 14 and the arrangement of spring contact ring 15 thereon, reference is made to the above description of the first specific embodiment. In addition to the mentioned components, the figures for this specific embodiment show a stator cover 28 which is fixed to stator 3 on the side opposite from cover 8, likewise via screw connections 9.

(38) Spring contact ring 15 in this specific embodiment is shown in greater detail in various views and illustrations in FIGS. 18A through 20. A total of three detent projections 30, 31, 32, which protrude radially inwardly into central opening 16 and which may also be referred to as snap-fit projections, are formed on radially inwardly facing circumferential surface 29 opposite from spring contact surface 26. The detent projections are uniformly spaced apart from one another (angular distance 120) in the circumferential direction, and are inclined toward rotor 2 in the axial direction. Due to their material and/or their geometry, they have spring-elastic properties, as described below.

(39) Trigger wheel 27 is shown separately in a perspective view in FIG. 26. Trigger wheel 27 has a plate-shaped design, and includes a hub 33 with a central opening 35. Markings for signal recognition are provided on the outer circumference of trigger wheel 27. A circumferential groove 34 is introduced into the outer circumference of hub 33. Detent projections 30, 31, 32 engage with the groove in a force-fit and/or form-fit manner when trigger wheel 27 is completely installed, so that the axial position of trigger wheel 27 is fixed. The elastic deformation of projections 30, 31, 32 is apparent from a comparison of FIGS. 11 and 16, with FIG. 11 illustrating projections 30, 31, 32 in the undeformed state, i.e., without trigger wheel 27, and FIG. 16 illustrating projections 30, 31, 32 in the deformed state, i.e., engaging with groove 34 in installed trigger wheel 27.

(40) Trigger wheel 27 is fixed and secured on camshaft adjuster 1 in the axial direction due to projections 30, 31, 32 which engage with circumferential groove 34.

(41) FIGS. 22A through 25 show one specific embodiment of a fastening ring 36 for a trigger wheel 27. In this specific embodiment, fastening ring 36 is provided with detent projections 30, 31, 32, but, unlike the two specific embodiments of spring contact ring 15 described above, includes no projections which protrude from the plane of the ring in the axial direction. In this specific embodiment, fastening ring 36 is used only for the arrangement and axial fixing of trigger wheel 27, and does not form a support for return spring 5, which may be supported with the aid of spring bolts 10, 11, 12, 13, 14 when such a ring 36 is used. In other respects, fastening ring 36 is the same as spring contact ring 15 described above, and reference is made to its description.

LIST OF REFERENCE NUMERALS

(42) 1 camshaft adjuster 2 rotor 3 stator 4 longitudinal axis 5 return spring 6 first end 7 second end 8 cover 9 screw connections 10 spring retaining bolt 11 spring guide bolt 12 spring bolt 13 spring bolt 14 spring bolt 15 spring contact ring, spring contact component 16 central opening 17 projection 18 projection 19 projection 20 recess 21 recess 22 recess 23 through hole 24 through hole 25 through hole 26 circumferential surface/contact surface 27 trigger wheel 28 stator cover 29 circumferential surface 30 detent projection 31 detent projection 32 detent projection 33 hub 34 circumferential groove 35 central opening 36 fastening ring