CAMSHAFT ADJUSTER HAVING TWO BALL JOINTS

Abstract

A camshaft adjuster (1) for variably adjusting an outer camshaft (5) and an inner camshaft (7) that is arranged concentrically thereto, including a stator (2) that can be connected to the outer camshaft (5), and a rotor (3) that is arranged concentrically to the stator (2), wherein the rotor (3) can be connected to the inner camshaft (7) in the manner of a first joint (9) on a first spherical contact surface (27). In order to axially secure the rotor (3) on the inner camshaft (7), force can be applied to the rotor (3) by way of a screw (4). The screw (4) can be connected to the inner camshaft (7) in the manner of a second joint (12) on a second spherical contact surface (28). A camshaft adjuster-camshaft combination having a camshaft adjuster, wherein the outer camshaft (5) is fixed on the stator (2) in a rotationally secured manner, and the inner camshaft (7) is fixed on the rotor (3) in a rotationally secured manner.

Claims

1-10. (canceled)

11. A camshaft adjuster for variably adjusting an outer camshaft and an inner camshaft situated concentrically thereto, the camshaft adjuster comprising: a stator connectable to the outer camshaft; a rotor situated concentrically to the stator, the rotor being connectable to the inner camshaft in the manner of a first joint on a first spherical contact surface, and force being applicable to the rotor via a screw for the purpose of axially securing the rotor on the inner camshaft, the screw connectable to the inner camshaft in the manner of a second joint on a second spherical contact surface.

12. The camshaft adjuster as recited in claim 11 wherein the first joint or the second joint is formed from a pair of spherically diametrically opposed joint contours.

13. The camshaft adjuster as recited in claim 11 wherein the first joint is formed by a convex joint contour on the camshaft side and a concave joint contour on the rotor side or by a concave joint contour on the camshaft side and a convex joint contour on the rotor side.

14. The camshaft adjuster as recited in claim 11 wherein the second joint is formed by a convex joint contour on the screw side and a concave joint contour on the rotor side or by a concave joint contour on the screw side and a convex joint contour on the rotor side.

15. The camshaft adjuster as recited inclaim 11 wherein the rotor is in direct contact with the inner camshaft in the first joint, or a first compensating part is inserted between the rotor and the inner camshaft.

16. The camshaft adjuster as recited in claim 15 wherein the first compensating part has a convex or concave contour on one or two surfaces.

17. The camshaft adjuster as recited in claim 11 wherein the screw is in direct contact with the inner camshaft in the second joint, or a second compensating part is inserted therebetween.

18. The camshaft adjuster as recited in claim 17 wherein the compensating part is present and has a convex or concave contour on one or two surfaces.

19. The camshaft adjuster as recited in claim 11 wherein a toothing is present on the inner camshaft, a diametrically opposed toothing being formed on the rotor, and the teeth being formed to permit a wobbling movement of the rotor relative to the inner camshaft around the first joint.

20. A camshaft adjuster-camshaft combination, comprising: a camshaft adjuster as recited in claim 11, the outer camshaft rotatably fixedly attached to the stator, and the inner camshaft rotatably fixedly attached to the rotor.

Description

DETAILED DESCRIPTION

[0031] The figures are only of a schematic nature and are used only for the sake of understanding the present invention. Identical elements or comparable elements are provided with identical reference numerals. Features of one specific embodiment may also be included in the other specific embodiments. They are thus interchangeable with each other.

[0032] A first specific embodiment of the present invention is described on the basis of FIG. 1. FIG. 1 shows a camshaft adjuster 1, which includes a stator 2, a rotor 3 and a screw or central screw 4. Stator 2 is fixedly connected to an outer camshaft 5. Screw 4 is connected to an inner camshaft 7 via a thread 6. Rotor 3 is axially guided on inner walls 8 of stator 2 in an axial direction or in the direction of a rotation axis A of camshaft adjuster 1, which determines the longitudinal direction.

[0033] Rotor 3 abuts an end face and/or a lateral surface of inner camshaft 7 via a first joint/ball joint 9. Only an abutment on the lateral surface is apparent in the first exemplary embodiment. A first spherical contact surface 27 is present in first joint/ball joint 9.

[0034] A camshaft-side joint contour 10 has a convex shape, and a rotor-side joint contour 11 has a concave shape. Moreover, screw 4 abuts rotor 3 via a second joint/ball joint 12. A rotor-side joint contour 13 has a concave shape, and a screw-side joint contour 14 (see FIG. 2 in this regard) has a convex shape. A second spherical contact surface 28 is present in second joint/ball joint 12.

[0035] In the first specific embodiment, first ball joint 9 is formed as a single piece by inner camshaft 7 on the camshaft side, i.e., camshaft-side joint contour 10 is a surface of inner camshaft 7. First ball joint 9 is also formed as a single piece by rotor 3 on the rotor side, i.e., rotor-side joint contour 11 is a surface of rotor 3. Second ball joint 12 is formed as a single piece by rotor 3 on the rotor side, i.e., rotor-side joint contour 13 is a surface of rotor 3. Second ball joint 12 is also formed as a single piece by screw 4 on the screw side, i.e., a screw-side joint contour is a surface of screw 4.

[0036] The illustration in FIG. 1 shows outer camshaft 5 and inner camshaft 7 in an ideally aligned manner, i.e., a center axis of outer camshaft 5 and a center axis of inner camshaft 7 are both situated coaxially on the sketched longitudinal axis A. This is done for representation purposes. If an angle error or an angle offset occurs between outer camshaft 5 and inner camshaft 7, rotor 3 may execute a wobbling movement around the inner camshaft on first ball joint 9 and on second ball joint 12. Rotor 3 is guided by stator 2.

[0037] Camshaft-side joint contour 10 is formed by a surface 15 of inner camshaft 7, which projects radially from inner camshaft 7. This designation, “radially projecting surface,” of surface 15 is not to be understood to mean that camshaft-side joint contour 10 is essentially in a radial plane but that surface 15 projects outwardly radially from a main body of inner camshaft 7. This terminology is furthermore used to make a distinction from an end face described below. Accordingly, rotor-side joint contour 11 is a radial inner surface of rotor 3. The description of radial surface 15 of inner camshaft 7 applies to radial inner surface 16 of rotor 3 in a diametrically opposed or complementary manner. In contrast, rotor-side joint contour 13 is formed by an end face 17 of rotor 3, and screw-side joint contour 14 is formed by an end face 18 of screw 4.

[0038] A second specific embodiment of the present invention is described on the basis of FIG. 2. In this second specific embodiment, camshaft-side joint contour 10 is formed by an end face 19 of inner camshaft 7, and rotor-side joint contour 11 of first ball joint 9 is formed by an end face 20 of rotor 3 facing inner camshaft 7. In second ball joint 12, rotor-side joint contour 13 is again formed by end face 17 of rotor 3.

[0039] In the second specific embodiment, end face 18 of screw 4 is essentially formed around rotation axis A in a radial plane. A compensating part 21 is provided between end face 18 and rotor-side joint contour 13. A planar surface of compensating part 21 abuts end face 18 of screw 4. Screw-side joint contour 14 is formed on compensating part 21. Joint contour 14 of compensating part 21 thus abuts joint contour 13 of rotor 3. In other words, second ball joint 12 is formed as a single piece by rotor 3 on the rotor side and is formed on the screw side by inserting compensating piece 21.

[0040] In other respects, the description of the first specific embodiment applies.

[0041] A third specific embodiment of the present invention is described on the basis of FIG. 3. In this third specific embodiment, first ball joint 9 is formed on the camshaft side by inserting a compensating part 22 and is formed on the rotor side by inserting a compensating part 23. Second ball joint 12 is furthermore formed on the rotor side by inserting compensating part 24 and is formed on the screw side by inserting a compensating part 21. This means that end face 19 of inner camshaft 7 abuts compensating part 22, end face 20 of rotor 3 abuts compensating part 23, compensating part 22 forms camshaft-side joint contour 10, compensating part 23 forms rotor-side joint contour 11 and camshaft-side joint contour 10 of compensating part 22 abuts rotor-side joint contour 11 of compensating part 23.

[0042] In second ball joint 12, end face 17 of rotor 3 abuts compensating part 24, end face 18 of screw 4 abuts compensating part 21, compensating part 21 forms screw-side joint contour 14, compensating part 24 forms rotor-side joint contour 13 and rotor-side joint contour 13 of compensating part 24 abuts screw-side joint contour 14 of compensating part 21.

[0043] An axial component of first ball joint 9, or a surface portion of first ball joint 9 which is normal to the longitudinal direction, is approximately the same or of the same size as an axial component of second ball joint 12 or a surface portion of second ball joint 12 which is normal to the longitudinal direction. A surface pressure of joint contours 10, 11, 13, and 14, which is generated by an axial force between screw 4 and inner camshaft 7, is therefore approximately the same or of the same size.

[0044] In other respects, the descriptions of the preceding specific embodiments apply.

[0045] A fourth specific embodiment of the present invention is described on the basis of FIG. 4. In this fourth specific embodiment, first ball joint 9 is formed on the camshaft side by inserting compensating part 22 and is formed on the rotor side by inserting compensating part 23.

[0046] In this fourth specific embodiment, second ball joint 12 is formed on the rotor side by inserting compensating part 24 and is formed as a single piece by screw 4 on the screw side. Compensating part 24 abuts end face 17 of rotor 3. A gap S is provided between rotor 3 and compensating part 24 in the radial direction. Due to gap S, compensating part 24 may slide on end face 17. This prevents a constraining force from being transmitted from screw 4 to rotor 3 via compensating part 24 in the radial direction in the event of a great angle offset between inner camshaft 7 and outer camshaft 5.

[0047] In other respects, the descriptions of the preceding specific embodiments apply.

[0048] A fifth specific embodiment of the present invention is described on the basis of FIGS. 5 and 6. In this fifth specific embodiment, second ball joint 12 is formed as a single piece by rotor 3 on the rotor side and is formed on the screw side by inserting compensating part 21.

[0049] A toothing 25 is formed on inner camshaft 7. More specifically, camshaft-side toothing 25 is formed on end face 19 of inner camshaft 7. Camshaft-side joint contour 10 is formed on end face 19 of inner camshaft 7 between the individual teeth of toothing 25 in the circumferential direction. This means that first ball joint 9 is formed as a single piece by inner camshaft 7 on the camshaft side.

[0050] A toothing 26, which is diametrically opposed or complementary to toothing 25, is formed on end face 20 of rotor 3, which faces inner camshaft 7. End face 20 of rotor 3 forms rotor-side joint contour 11 between the teeth of toothing 26 in the circumferential direction. This means that first ball joint 9 is formed as a single piece by rotor 3 on the rotor side.

[0051] In the fifth specific embodiment, therefore, first ball joint 9 and second ball joint 12 facilitate a wobbling movement of rotor 3 relative to inner camshaft 7. A torque or a rotary power may be transmitted between rotor 3 and inner camshaft 7 via camshaft-side toothing 25 and rotor-side toothing 26.

[0052] FIG. 6 shows a top view of end face 19 of inner camshaft 7. Camshaft-side joint contour 10 and camshaft-side toothing 25 are apparent. In the fifth specific embodiment, toothing 25 includes, for example, five teeth. This is only an example and should not be understood to be limiting. As is apparent from the illustration in FIG. 6, one tooth of toothing 25 and one surface section of camshaft-side joint contour 10 are each alternately formed on end face 19 of inner camshaft 7 in circumferential direction U.

[0053] In other respects, the descriptions of the preceding specific embodiments apply.

[0054] FIG. 7 illustrates an example of the area of the present invention. Identical or comparable elements are marked with the same reference numerals and are therefore not described again.

[0055] In camshaft adjuster 1 illustrated in FIG. 7, rotor 3 is secured axially, not by a screw or center screw, by only by abutting inner walls 8 of stator 2.

[0056] First ball joint 9 is formed as a single piece by inner camshaft 7 on the camshaft side and is formed as a single piece by rotor 3 on the rotor side. This means that end face 19 of inner camshaft 7 forms camshaft-side joint contour 10, and rotor-side end face 20 of rotor 3, which faces inner camshaft 7, forms rotor-side joint contour 11. Toothing 25 is furthermore mounted on camshaft-side end face 19, and toothing 26 is mounted on rotor-side end face 20. Camshaft-side toothing 25 and rotor-side toothing 26 are formed to be diametrically opposed or complementary to each other.

[0057] In other words, a difference between the fifth specific embodiment of the present invention and the example illustrated on the basis of FIG. 7 for the area of the present invention is apparent in that rotor 3 of camshaft adjuster 1 illustrated in FIG. 7 is not supported on inner camshaft 7 by an axial force of a screw. Instead, rotor 3 of camshaft adjuster 1 is supported in a floating manner, as illustrated in FIG. 7. The floating bearing, in connection with first ball joint 9, permits a wobbling movement of rotor 3 on inner camshaft 7. In camshaft adjuster 1 of the example illustrated on the basis of FIG. 7 for the area of the present invention, an angle offset between inner camshaft 7 and the outer camshaft 5 may thus be compensated for. At the same time, a torque is transmittable from rotor 3 to inner camshaft 7 via toothings 25 and 26.

[0058] In other respects, the descriptions of the preceding specific embodiments apply.

LIST OF REFERENCE NUMERALS

[0059] 1 camshaft adjuster [0060] 2 stator [0061] 3 rotor [0062] 4 screw/center screw [0063] 5 outer camshaft [0064] 6 thread [0065] 7 inner camshaft [0066] 8 inner wall [0067] 9 first joint/first ball joint [0068] 10 camshaft-side joint contour [0069] 11 rotor-side joint contour [0070] 12 second joint/second ball joint [0071] 13 rotor-side joint contour [0072] 14 screw-side joint contour [0073] 15 radial surface [0074] 16 radial inner surface [0075] 17 rotor-side end face [0076] 18 screw-side end face [0077] 19 camshaft-side end face [0078] 20 rotor-side end face [0079] 21 screw-side compensating part [0080] 22 camshaft-side compensating part [0081] 23 rotor-side compensating part [0082] 24 rotor-side compensating part [0083] 25 camshaft-side toothing [0084] 26 rotor-side toothing [0085] 27 first spherical contact surface [0086] 28 second spherical contact surface [0087] A rotation axis [0088] S gap [0089] U circumferential direction