Camshaft adjuster

Abstract

An arrangement of a camshaft phaser (1) which has a drive element (2) and at least two driven elements (3, 4), whereby the camshaft phaser (1) has a first control valve (7) arranged concentrically to the camshaft phaser (1), and a second control valve (8) arranged off-centered with respect to the rotational axis (5) of the camshaft phaser (1).

Claims

1. A camshaft phaser comprising: a single drive element rotating at a first speed; a first driven element; a second driven element, the first driven element and second driven element each being driven by the single drive element, each of the single drive, first driven and second driven elements arranged coaxially to a rotational axis of the camshaft phaser; the first and second driven elements and the single drive element having several radially oriented vanes, the several radially oriented vanes forming several working chambers fillable with a hydraulic medium under pressure so that a relative rotation is possible between the single drive element and one of the first and second driven elements as well as between the first and second driven elements themselves; a first control valve arranged coaxially to the rotational axis; and a second control valve arranged off-centered with respect to the rotational axis, the first and second control valves for regulating pressurization of the several working chambers.

2. The camshaft phaser as recited in claim 1 wherein the first control valve regulates a first relative rotation between the drive element and the first driven element, while the second control valve regulates a second relative rotation between the drive element and the second driven element.

3. The camshaft phaser as recited in claim 1 wherein the first control valve is a central valve and is arranged in a hub of the camshaft phaser.

4. The camshaft phaser as recited in claim 3 further comprising a central magnet for actuating the central valve.

5. The camshaft phaser as recited in claim 1 wherein the second control valve is a cartridge valve.

6. The camshaft phaser as recited in claim 1 wherein the first driven element is connectable to a first camshaft, while the second driven element is connectable to a second camshaft.

7. A camshaft system comprising a first camshaft, a second camshaft and the camshaft phaser as recited in claim 1, the first driven element connectable to the first camshaft, the second driven element connectable to the second camshaft, and when the working chambers are filled with a hydraulic medium under pressure, a relative rotation occurs of both the first and second driven elements with respect to each other and thus also of the first and second camshafts with respect to each other, as well as another relative rotation of the first and second driven elements with respect to the drive element.

8. A camshaft phaser comprising: a drive element; a first driven element; a second driven element, each of the drive, first driven and second driven elements arranged coaxially to a rotational axis of the camshaft phaser; the first and second driven elements and the drive element having several radially oriented vanes, the several radially oriented vanes of each of the first and second driven elements and the drive element overlapping axially and forming several working chambers fillable with a hydraulic medium under pressure so that a relative rotation is possible between the drive element and one of the first and second driven elements as well as between the first and second driven elements themselves; a first control valve arranged coaxially to the rotational axis; and a second control valve arranged off-centered with respect to the rotational axis, the first and second control valves for regulating pressurization of the several working chambers.

9. The camshaft phaser as recited in claim 8 wherein the first control valve regulates a first relative rotation between the drive element and the first driven element, while the second control valve regulates a second relative rotation between the drive element and the second driven element.

10. The camshaft phaser as recited in claim 8 wherein the first control valve is a central valve and is arranged in a hub of the camshaft phaser.

11. The camshaft phaser as recited in claim 10 further comprising a central magnet for actuating the central valve.

12. The camshaft phaser as recited in claim 8 wherein the second control valve is a cartridge valve.

13. The camshaft phaser as recited in claim 8 wherein the first driven element is connectable to a first camshaft, while the second driven element is connectable to a second camshaft.

14. A camshaft system comprising a first camshaft, a second camshaft and the camshaft phaser as recited in claim 8, the first driven element connectable to the first camshaft, the second driven element connectable to the second camshaft, and when the working chambers are filled with a hydraulic medium under pressure, a relative rotation occurs of both the first and second driven elements with respect to each other and thus also of the first and second camshafts with respect to each other, as well as another relative rotation of the first and second driven elements with respect to the drive element.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) Embodiments of the invention are depicted in the figures.

(2) The following is shown:

(3) FIG. 1 a camshaft phaser according to the invention, in a longitudinal section along the rotational axis of the camshaft phaser; and

(4) FIG. 2 a camshaft phaser according to the invention, in a cross-sectional view along the rotational axis of the camshaft phaser.

DETAILED DESCRIPTION

(5) FIG. 1 shows a camshaft phaser 1 according to the invention, in a longitudinal section along the rotational axis 5 of the camshaft phaser 1. The camshaft phaser 1 has a drive element 2, a first driven element 3, a second driven element 4, sealing means 17 as well as several radially oriented vanes 6 of the drive element 2 and of the driven elements 3, 4. The hub 10 of the first driven elementwhich at the same time is the hub of the camshaft phaser 1is arranged non-rotatably and concentrically on an axial end of a first camshaft 18. The first camshaft 18 has a concentric central channel 13 through which the hydraulic medium can be fed under pressure. The first control valve 7, which comprises a sleeve 15 and a control piston 14, is likewise arranged concentrically in the central channel 13 in the vicinity of the hub 10. The control valve 7 is arranged axially rigidly with respect to the first camshaft. The control piston 14 is arranged axially movably with respect to the sleeve 15 and it can be spring-loaded in an axial direction with respect to the sleeve 15 in order to remain in a resting position when it is in its non-actuated state. The control piston 14 is actuated by means of a central magnet 11 that is arranged on an end face on the side of the camshaft phaser 1 facing away from the camshaft. The central magnet 11 actuates the control piston 14 in the axial direction by means of an actuating pin 20, thus moving the control piston 14 relative to the sleeve 15. The sleeve 15 and the control piston 14 are each provided with openings known from the state of the art, said openings then being opened or closed during an axial relative movement. The hydraulic medium is fed through the central channel 13 along the rotational axis 5 into the first control valve 7. Depending on the position of the control piston 14 relative to the sleeve 15, this hydraulic medium is distributed among the corresponding hydraulic-medium channels 12 and thus radially through the hub 10, said channels each opening up into corresponding working chambers A, B.

(6) The working chambers C, D are supplied by means of a second control valve 8 that is configured here as a cartridge valve 9. This second control valve 8 is not arranged concentrically to the rotational axis 5, but rather, it can be attached as desired to a receptacle in the engine. Via hydraulic-medium channels 16, the hydraulic medium reaches the working chambers C, D of the second driven element 4. The cartridge valve 9 comprises a hydraulic part that is in communication with hydraulic-medium channels and that, like the first control valve 7, can distribute hydraulic medium from a pressure pump among the appertaining hydraulic-medium channels. The actuation is carried out by means of a solenoid 21. The hydraulic part of the cartridge valve 9 is likewise equipped with a control piston whose mode of operation is familiar to the person skilled in the art, so that it will not be elaborated upon here.

(7) The arrangement according to the invention makes it clear that, in order to independently actuate the first driven element 3 and the second driven element 4, it is advantageous to arrange two separate control valves in the installation space, so that direct hydraulic-medium channels can be employed. The two control valves can be supplied with hydraulic medium from the pressure pump either via a single feed line or else separately from each other, and even employing two different pressure pumps.

(8) FIG. 2 shows a camshaft phaser 1 according to the invention, in a cross-section perpendicular to the rotational axis 5 of the camshaft phaser 1. This depiction clearly shows the formation of the working chambers A, B, D, C by the driven elements 3 and 4 with the drive element 2. Together with a vane pair of the drive element 2, each vane 6 of a driven element 3 or 4 forms two working chambers A and B. Thus, together with the vanes 6 of the drive element 2, the vane 6 of the driven element 3 defines the working chambers A and B. In contrast, in a comparable manner, the driven element 4, together with the drive element 2, forms the working chambers C and D. The radial, outer ends of the vanes 6 of the driven elements 3 and 4 have sealing means 17 that separate the working chambers in an oil-tight manner. Moreover, at least between a driven element 3 or 4 and the drive element 2, the camshaft phaser 1 has a spring element 13 in the circumferential direction 12. Here, both driven elements 3 and 4 are tensioned with the drive element 2 by means of a spring element 13.

(9) Therefore, when the working chamber A or B is filled with hydraulic medium, the driven element 3 can be rotated relative to the drive element 2. Filling the working chambers C and D with hydraulic medium causes a relative rotation between the driven element 4 and the drive element 2.

LIST OF REFERENCE NUMERALS

(10) 1 camshaft phaser 2 drive element 3 first driven element 4 second driven element 5 rotational axis 6 vanes 7 first control valve 8 second control valve 9 cartridge valve 10 hub 11 central magnet 12 hydraulic-medium channel 13 central channel 14 control piston 15 sleeve 16 hydraulic-medium channel 17 sealing means 18 first camshaft 19 second camshaft 20 actuating pin 21 solenoid A working chamber B working chamber C working chamber D working chamber