Camshaft adjusting system having camshaft adjusters which are arranged radially and axially inside one another

Abstract

A camshaft adjusting system (1) is provided for a first camshaft (2) and a second camshaft (3) which are arranged concentrically with respect to one another, the second camshaft being arranged inside the first camshaft. A hydraulic camshaft adjuster (4) of the vane-cell type is set up for the adjustment of the first camshaft, and an electric camshaft adjuster (5) is set up for the adjustment of the second camshaft. A rotor contact flange (17) of an output ring (6) of the electric camshaft adjuster is arranged radially inside a first cover (23) of the hydraulic adjuster, the output ring which is equipped for the transmission of torque to the second camshaft is arranged at least partially radially and axially inside a rotor (7) of the hydraulic camshaft adjuster. A camshaft adjusting unit is also provided having a camshaft adjusting system of this type and two camshafts.

Claims

1. A camshaft adjusting system for a first camshaft and a second camshaft which are arranged concentrically with respect to one another, the second camshaft being arranged inside the first camshaft, the camshaft adjusting system comprising: a vane-cell type hydraulic camshaft adjuster configured to adjust the first camshaft, the hydraulic camshaft adjuster including a first cover and a rotor; and an electric camshaft adjuster configured to adjust the second camshaft, the electric camshaft adjuster including: an output ring having a rotor contact flange, the rotor contact flange is arranged radially inside the first cover, and the output ring is configured to transmit torque to the second camshaft arranged at least partially radially and axially inside the rotor.

2. The camshaft adjusting system as claimed in claim 1, wherein the hydraulic camshaft adjuster is configured to adjust the first camshaft independently of the second camshaft.

3. The camshaft adjusting system as claimed in claim 1, wherein the output ring is mounted at least one of radially or axially inside the rotor.

4. The camshaft adjusting system as claimed in claim 3, further comprising a plain bearing between the output ring and the rotor.

5. The camshaft adjusting system as claimed in claim 1, wherein the output ring is step-shaped in a longitudinal section.

6. The camshaft adjusting system as claimed in claim 1, wherein the output ring includes the rotor contact flange oriented in an axial direction, and an inner camshaft contact flange oriented axially and extending in an opposite direction from the rotor contact flange.

7. The camshaft adjusting system as claimed in claim 1, wherein the output ring includes an internal toothing system that is in contact with an intermediate gear mechanism that is configured to be moved by the electric camshaft adjuster.

8. The camshaft adjusting system as claimed in claim 7, wherein the intermediate gear mechanism comprises a harmonic drive.

9. The camshaft adjusting system as claimed in claim 1, wherein the hydraulic camshaft adjuster further comprises a stator that is connected to a drive gear by which a chain drive acting on the drive gear is adapted to be connected to the first camshaft.

10. A camshaft adjusting unit comprising: a first camshaft; a second camshaft arranged concentrically inside the first camshaft; a vane-cell type hydraulic camshaft adjuster connected to the first camshaft and configured to adjust a rotational position of the first camshaft relative to a drive, the hydraulic camshaft adjuster including a first cover, a stator, and a rotor located within the stator; and an electric camshaft adjuster connected to the second camshaft and configured to adjust a rotational position of the second camshaft relative to the drive and relative to the first camshaft, the electric camshaft adjuster including: an output ring having a rotor contact flange, the rotor contact flange is arranged radially inside the first cover, and the output ring is configured to transmit torque to the second camshaft arranged at least partially radially and axially inside the rotor.

11. The camshaft adjusting unit of claim 10, wherein the hydraulic camshaft adjuster is configured to adjust the first camshaft independently of the second camshaft.

12. The camshaft adjusting unit as claimed in claim 10, wherein the output ring is mounted at least one of radially or axially completely inside the rotor.

13. The camshaft adjusting unit as claimed in claim 12, further comprising a bearing between the output ring and the rotor.

14. The camshaft adjusting unit as claimed in claim 10, wherein the output ring is step-shaped in a longitudinal section.

15. The camshaft adjusting unit as claimed in claim 10, wherein the output ring includes the rotor contact flange oriented in an axial direction, and an inner camshaft contact flange oriented axially and extending in an opposite direction from the rotor contact flange.

16. The camshaft adjusting unit as claimed in claim 10, further comprising an intermediate gear mechanism that is configured to be moved by the electric camshaft adjuster that engages an internal toothing of the output ring.

17. The camshaft adjusting unit as claimed in claim 16, wherein the intermediate gear mechanism comprises a harmonic drive.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) In the following text, embodiments will be described in greater detail with the aid of figures, in which one exemplary embodiment is shown and in which:

(2) FIG. 1 shows a longitudinal sectional view of a camshaft adjusting system and two camshafts, and

(3) FIG. 2 shows a perspective partial view of the camshaft adjusting system.

DETAILED DESCRIPTION

(4) The figures are merely diagrammatic in nature and serve only for the comprehension of the embodiments. The same elements are provided with the same designations.

(5) FIG. 1 shows a longitudinal sectional view of a camshaft adjusting system 1 for a first camshaft 2 and a second camshaft 3. The two camshafts 2, 3 are arranged concentrically with respect to one another, the second camshaft 3 being arranged radially inside the first camshaft 2. The camshaft adjusting system 1 has a hydraulic camshaft adjuster 4 which serves for the adjustment of the first camshaft 2, and an electric camshaft adjuster 5 which serves for the adjustment of the second camshaft 3.

(6) Here, the two camshaft adjusters 4, 5 are arranged in such a way that an output ring 6 of the electric camshaft adjuster 5 is arranged radially and axially inside a rotor 7 of the hydraulic camshaft adjuster 4. In addition to the rotor 7, the first camshaft adjuster 2 also has a stator 8 (see FIG. 2) and is therefore a hydraulic camshaft adjuster of the vane-cell type.

(7) The electric camshaft adjuster 5 is driven by an electric motor 9 and is connected to the latter via an Oldham coupling 10 and an intermediate gear mechanism 11. An Oldham coupling is a non-switchable, torsionally rigid coupling which can compensate for a radial offset of two parallel shafts. Therefore, a radial elastic deformation of a flanged bushing 12 of the intermediate mechanism 11 is compensated for by way of the coupling, with the result that a concentricity fault is not forwarded to an output shaft 13 of the electric camshaft adjuster 5. An Oldham coupling is known per se from the prior art, for which reason it is not described in greater detail at this point.

(8) The intermediate gear mechanism 11 is configured as what is known as a harmonic drive, that is to say as a gear mechanism with an elastic transmission element 14 which transmits torque from the output shaft 13 to the flanged bushing 12. A gear mechanism of this type is also already known from the prior art, for which reason a detailed description of the intermediate gear mechanism 11 is dispensed with at this point.

(9) The flanged bushing 12 has an external toothing system 15 which meshes with an internal toothing system 16 of the output ring 6 (see also FIG. 2). As an alternative, the output ring 6 is also called an output internal gear 6.

(10) In longitudinal section, the output ring 6 has a shape of step-like configuration which is composed of three sections: a rotor contact flange 17, an intermediate section 18 and an inner camshaft contact flange 19. The intermediate section 18 is of ring-like configuration and connects the two flanges 17, 19 to one another. The rotor contact flange 17 extends from the radially outer end of the intermediate section 18 in the axial direction in a first direction, namely toward the intermediate gear mechanism 11, and the inner camshaft contact flange 19 extends from the radially inner end of the intermediate section 18 in the axial direction in a second direction, in an opposed manner with respect to the first direction, that is to say away from the intermediate gear mechanism 11.

(11) A radial bearing or a plain bearing 20 is provided between the output ring 6 and the rotor 7, as a result of which the output ring 6 of the electric camshaft adjuster 5 can be rotated independently of and relative to the rotor 7 of the hydraulic camshaft adjuster 4. As a result, the angular adjustment of the two camshafts 2, 3 can be implemented completely independently of one another.

(12) The stator 8 (see FIG. 2) is connected to a drive gear 21 which has an external toothing system 22. The drive gear 21 can be connected in a torque-transmitting manner via the external toothing system 22 via a chain drive to an outer shaft, for example a crankshaft (not shown). The drive gear 21 and the stator 8 are connected fixedly to a first cover 23 so as to rotate with it on a first side in the axial direction which faces the intermediate gear mechanism 11, and are connected fixedly to a second cover 24 so as to rotate with it on a second side in the axial direction which faces away from the intermediate gear mechanism 11. The rotor 7 is likewise arranged between the two covers 23, 24, but can also rotate relative to the latter. The rotor 7 is fixed by a bearing hub 25 on the outer (first) camshaft 2 in such a way that the rotor 7 cannot be displaced as viewed in the axial direction. To this end, the bearing hub 25 is connected to the outer camshaft 2 fixedly in axial terms and so as to rotate with it.

LIST OF DESIGNATIONS

(13) 1 Camshaft adjusting system

(14) 2 First camshaft

(15) 3 Second camshaft

(16) 4 Hydraulic camshaft adjuster

(17) 5 Electric camshaft adjuster

(18) 6 Output ring/output internal gear

(19) 7 Rotor

(20) 8 Stator

(21) 9 Electric motor

(22) 10 Oldham coupling

(23) 11 Intermediate gear mechanism

(24) 12 Flanged bushing

(25) 13 Output shaft

(26) 14 Elastic transmission element

(27) 15 External toothing system

(28) 16 Internal toothing system

(29) 17 Rotor contact flange

(30) 18 Intermediate section

(31) 19 Inner camshaft contact flange

(32) 20 Plain bearing

(33) 21 Drive gear

(34) 22 External toothing system

(35) 23 First cover

(36) 24 Second cover

(37) 25 Bearing hub