DUAL CAM PHASER

Abstract

A dual cam phaser for an internal combustion engine, the dual cam phaser including a stator which is drivable by a crankshaft; a rotor which rotatable relative to the stator; a first camshaft; a second camshaft; and a mechanical switching element which is connected to the first camshaft and the second camshaft, wherein the first camshaft and the second camshaft are arranged coaxial with one another, wherein the first camshaft or the second camshaft is connected with the rotor to rotate together with the rotor, and wherein a phase difference between the first camshaft and the second is adjustable by the mechanical switching element.

Claims

1. A dual cam phaser for an internal combustion engine, the dual cam phaser comprising: a stator which is drivable by a crankshaft; a rotor which rotatable relative to the stator; a first camshaft; a second camshaft; and a mechanical switching element which is connected to the first camshaft and the second camshaft, wherein the first camshaft and the second camshaft are arranged coaxial with one another, wherein the first camshaft or the second camshaft is connected with the rotor to rotate together with the rotor, and wherein a phase difference between the first camshaft and the second is adjustable by the mechanical switching element.

2. The dual cam phaser according to claim 1, wherein the mechanical switching element is transferable between a first switching position in which the first camshaft is in a first phase position relative to the second camshaft and a second switching position in which the first camshaft is in a second phase position relative to the second camshaft.

3. The dual cam phaser according to claim 1, wherein the first camshaft is an inlet camshaft and the second camshaft is an outlet camshaft.

4. The dual cam phaser according to claim 1, wherein the first camshaft and the second camshaft are connected by the mechanical switching element so that the first camshaft and the second camshaft are rotated in opposite directions relative to each other as the rotor rotates.

5. The dual cam phaser according to claim 1, wherein the mechanical switching element includes a first adjusting element and a second adjusting element, wherein the first adjusting element and the second adjusting element pivot about a common pivot joint, and wherein the first adjusting element is connected to the first camshaft and the second adjusting element is connected to the second camshaft.

6. The dual cam phaser according to claim 5, wherein the mechanical switching element includes a third adjusting element, wherein the first adjusting element, the second adjusting element and the third adjusting element are connected to the common pivot joint, and wherein the third adjusting element is connected to a connection component that is fixed at the stator.

7. The dual cam phaser according to claim 6, wherein the connection component is a housing or a cover of the cam phaser.

8. The dual cam phaser according to claim 6, wherein the third adjusting element is connected to the connection component by a stator connection element which connects the connection component to the stator.

9. The dual cam phaser according to claim 5, wherein the second camshaft is connected to the rotor by a rotor connection element, and wherein the second adjusting element is connected to the second camshaft by the rotor connection element.

10. The dual cam phaser according to claim 2, wherein the mechanical switching element includes a spring element, wherein a spring force of the spring element is opposed to a movement of the mechanical switching element between the first switching position and the second switching position.

11. The dual cam phaser according to claim 10, wherein the spring element is a spiral spring.

12. The dual cam phaser according to claim 10, wherein the mechanical switching element includes a mechanism which connects the first camshaft with the second camshaft.

13. The dual cam phaser according to claim 12, wherein the mechanism enables the first camshaft and the second camshaft to rotate in a fixed ratio and in opposite directions relative to one another.

14. The dual cam phaser according to claim 10, wherein the switching element includes a stop which defines a maximum change in a phase difference between the first camshaft and the second camshaft.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Further advantages of the invention will become apparent from the description and the drawing figure. The invention is described in greater detail based on advantageous embodiments with reference to the drawing figure, wherein:

[0024] FIG. 1 shows a first embodiment of a dual cam phaser according to the invention in a first state;

[0025] FIG. 2 shows the cam phaser from FIG. 1 in a second state;

[0026] FIG. 3 shows the cam phaser from FIG. 1 in a third state; and

[0027] FIG. 4 shows a partial perspective view of a second illustrative embodiment of a dual cam phaser according to the invention.

DETAILED DESCRIPTION OF THE INVENTION

[0028] FIG. 1 shows a dual cam phaser 1 according to the invention in a first embodiment, said phaser having a toothed ring 2 for mounting a crankshaft (not shown here). The dual cam phaser 1 furthermore comprises a stator 3 (although not visible here), which is connected to the toothed ring 2 for conjoint rotation therewith, and a rotor 4 (although likewise not visible here), which is arranged so as to be rotatable relative to the stator 3. Relative to the stator 3 there is a component 5 arranged in a fixed manner, here in the form of a cover, which covers the stator 3 and the rotor 4. In this first embodiment, the component 5 is secured on the stator 3 by means of a plurality of stator connection elements 6. The component 5 has a central opening 7, through which the ends of two coaxially arranged camshafts 8, 9 project. In this specific case, the first camshaft 8 is arranged in such a way as to be surrounded by the second camshaft 9, and the second camshaft 9 is furthermore connected to the rotor 4 for conjoint rotation therewith. Furthermore, the first camshaft 8 is designed as an inlet camshaft and the second camshaft 9 is designed as an outlet camshaft. The dual cam phaser 1 furthermore comprises a first switching element 10, which is arranged externally on the cam phaser 1.

[0029] The switching element 10 has three adjusting elements 11, 12, 13, which are connected pivotably to one another by a common pivot joint 14. In this specific case, the adjusting elements 11, 12, 13 are a first adjusting element 11, a second adjusting element 12 and a third adjusting element 13. In this case, the first adjusting element 11 is arranged so as to be connected pivotably to the first camshaft 8, the second adjusting element 12 is arranged so as to be connected pivotably to the second camshaft 9, and the third adjusting element 13 is arranged so as to be connected pivotably to the component 5. In this specific case, the first adjusting element 11 is connected to the first camshaft 8 by means of a switching connection element 15, and the second adjusting element 12 is connected to the second camshaft 9 by means of a rotor connection element 16. The second camshaft 9 is furthermore connected to the rotor 4 by means of a plurality of these rotor connection elements 16. The third adjusting element 13 is connected to the component 5 by means of one of the stator connection elements 6 already mentioned and is thus also connected functionally to the stator 3.

[0030] The dual cam phaser 1 in FIG. 1 is in a possible first state or initial state. From this state, a phase difference between the first camshaft 8 and the second camshaft 9 can be changed by rotating the rotor 4. If the rotor 4 is rotated, the second camshaft 9 connected to the rotor 4 for conjoint rotation therewith is also rotated. In the illustrative embodiment shown here, this is specifically a left-hand rotation or counterclockwise rotation. By means of the first switching element 10 connected to the two camshafts 8, 9, the left-hand rotation of the second camshaft 9 initially results in a right-hand rotation or clockwise rotation of the first camshaft 8. This right-hand rotation continues as far as a state of the cam phaser 1 in which the second adjusting element 12 and thus also the rotor connection element 16 arranged thereon is arranged on a straight line with the common pivot joint 14 and the axis of the camshafts 8, 9. This state is shown by FIG. 2.

[0031] In FIG. 2, the dual cam phaser from FIG. 1 is illustrated in a second state. All the components that are visible in FIG. 1 can also be seen here in FIG. 2. As already mentioned, in the second state of the cam phaser 1 which is illustrated here in FIG. 2, the second adjusting element 12 and thus also the rotor connection element 16 arranged thereon is arranged on a straight line 17 with the common pivot joint 14 and the axis of the camshafts 8, 9. Here, the straight line 17 is indicated by means of a dash-dotted line.

[0032] Moreover, the first and the second state of the cam phaser define a maximum phase difference that can be set between the camshafts 8, 9. If the left-hand rotation of the rotor 4 which has already been described above, and thus the second camshaft 9, is continued beyond the second state of the cam phaser 1 which is shown here, this then also results in a left-hand rotation of the first camshaft 8 and thus a reduction in the phase difference between the camshafts 8, 9. The simultaneous left-hand rotation of the two camshafts 8, 9 continues as far as a state of the cam phaser 1 in which further left-hand rotation is inhibited by means of the third adjusting element 13. This state is illustrated in FIG. 3.

[0033] FIG. 3 shows the dual cam phaser from FIGS. 1 and 2 in a third state. All the components that are visible in FIGS. 1 and 2 can also be seen here in FIG. 3. As already mentioned, in the third state of the cam phaser 1 which is illustrated here in FIG. 3, further left-hand rotation of the camshafts 8, 9 is inhibited by means of the third adjusting element 13.

[0034] If the rotor 4 or the second camshaft 9 is then rotated back again or transferred by means of a right-hand rotation into the initial state of the cam phaser 1, a right-hand rotation of the first camshaft 8 also occurs at first. However, this right-hand rotation of the camshaft 8 continues only as far as the second state illustrated in FIG. 2. A further right-hand rotation of the second camshaft 9 results in a left-hand rotation of the first camshaft 8. The first state or initial state of the cam phaser 1, which is illustrated in FIG. 1, is achieved as soon as further right-hand rotation of the second camshaft 9 is inhibited, but this time by means of the first adjusting element 11.

[0035] In FIG. 4, a dual cam phaser 1 according to the invention is illustrated in a second embodiment and in a partial view. In this second embodiment too, the cam phaser 1 comprises the stator 3 (once again not visible here) and the rotor 4 (likewise not visible here) as well as the component 5, which is arranged in a fixed manner relative to the stator 3 and which in this case too is designed as a cover with a central opening 7. Once again, the ends of the coaxially arranged camshafts 8, 9 project through this opening 7, in the same way as in the cam phaser 1 in FIGS. 1 to 3. Here too, the second camshaft 9 is furthermore connected to the rotor 4 for conjoint rotation therewith. However, the camshafts 8, 9 and the component 5 in this second embodiment are connected to one another by means of a second switching element 18.

[0036] The second switching element 18 comprises a spring element 19, here in the form of a spiral spring, and a mechanism 20, here in the form of two gearwheelsnot visible here. The spring element 19 is retained, on the one hand, by a first retention element 21 on the second camshaft 9 and, on the other hand, by a second retention element 22 on the component 5. The mechanism 20 connects the camshafts 8, 9 functionally in such a way that rotation of the second camshaft 9 connected to the rotor 4 results in an opposite rotation of the first camshaft 8. This changes the phase difference between the camshafts 8, 9.

[0037] The second switching element 18 furthermore has a stop 23 having a stop projection 24 and a stop pin 25, wherein the stop projection 24 is attached to the first camshaft 8 and the stop pin 25 is attached to the component 5. The opposed rotation of the camshafts 8, 9 continues until the stop projection 24 is resting against the stop pin 25, whereby the maximum phase difference between the camshafts has been achieved. Further rotation of the second camshaft 9 leads to joint rotation of both camshafts 8, 9 in the same direction and against the force of the spring element.

[0038] All the features explained and shown in conjunction with the individual embodiments of the invention can be provided in various combinations in the subject matter according to the invention in order to simultaneously achieve the advantageous effects thereof. The scope of protection of the present invention is given by the claims and is not restricted by the features explained in the description or shown in the figures.