Cam phasing systems and methods
Cam phasing systems and methods are provided. In particular, a cam phasing system is provided that includes a reduced number of components when compared to current mechanical cam phasing systems. The cam phasing system includes a helix locking design that is configured to frictionally lock an helix rod during cam torque pulses.
1. A cam phasing system configured to vary a rotational relationship between a camshaft and a crankshaft of an internal combustion engine, the cam phasing system comprising:
a sprocket hub configured to be coupled to the crankshaft;
a cradle rotor configured to be coupled the camshaft;
a spider rotor configured to be coupled to the cradle rotor, wherein the spider rotor is configured to rotate to a predetermined rotational offset relative to the sprocket hub in response to a force applied to the spider rotor; and
an actuator coupled to the spider rotor through a compliance mechanism, wherein the actuator is configured to selectively apply the force to the spider rotor through the compliance mechanism, and wherein the compliance mechanism is coupled between the spider rotor and the actuator and includes at least one spring arranged to apply and maintain the force from the actuator on the spider rotor.
2. The cam phasing system of claim 1 , wherein the force maintained on the spider rotor by the compliance mechanism is further configured to ensure that the cradle rotor reaches the predetermined rotational offset relative to the sprocket hub.
3. The cam phasing system of claim 1 , further comprising an intermediate ring coupled to the spider rotor via the at least one spring.
4. The cam phasing system of claim 3 , wherein the actuator is further configured to apply an input displacement so as to rotate the intermediate ring relative to the spider rotor.
5. The cam phasing system of claim 3 , wherein the at least one spring includes a coil portion, the coil portion having a first end and a second end.
6. The cam phasing system of claim 5 , wherein the spider rotor includes at least one protrusion extending axially from a surface of the spider rotor so as to extend through the coil portion.
7. The cam phasing system of claim 6 , wherein the intermediate ring is configured to engage the first end and the second end.
8. The cam phasing system of claim 6 , wherein the intermediate ring includes at least one slot within which the first end and the second end are received so as to pre-bias the first end and the second end towards one another.
9. The cam phasing system of claim 8 , wherein when the intermediate ring is rotated relative to the spider rotor, the slot engages the first end so as to bias the first end towards the second end.
10. The cam phasing system of claim 9 , wherein the biasing applies a corresponding force onto the protrusion via the coil portion of the spring, thereby transferring the force from the intermediate ring to the spider rotor.
11. The cam phasing system of claim 1 , wherein the compliance mechanism includes a plurality of compliance mechanisms.
12. A cam phasing system configured to vary a rotational relationship between a camshaft and a crankshaft of an internal combustion engine, the cam phasing system comprising:
a sprocket hub configured to be coupled to the crankshaft;
a cradle rotor configured to be coupled the camshaft;
a spider rotor configured to be coupled to the cradle rotor;
an actuator configured to supply an input displacement;
an intermediate ring coupled to the actuator and configured to receive the input displacement; and
a compliance mechanism coupled between the intermediate ring and the spider rotor, wherein the compliance mechanism includes a spring configured to, upon the input displacement being supplied to the intermediate ring, supply and maintain a force on the spider rotor until the spider rotor reaches a predetermined rotational offset relative to the sprocket hub.
13. The cam phasing system of claim 12 , wherein the force maintained on the spider rotor by the compliance mechanism is further configured to ensure that the cradle rotor reaches a predetermined rotational offset relative to the sprocket hub.
14. The cam phasing system of claim 12 , wherein the spring includes a coil portion, the coil portion having a first end and a second end.
15. The cam phasing system of claim 14 , wherein the spider rotor includes at least one protrusion extending axially from a surface of the spider rotor so as to extend through the coil portion.
16. The cam phasing system of claim 12 , wherein the spider rotor includes a plurality of protrusions arranged circumferentially around the spider rotor.
17. The cam phasing system of claim 16 , wherein the compliance mechanism includes a plurality of compliance mechanisms each including a spring having a first end and a second end extending from a coil portion, and wherein the intermediate ring includes a plurality of slots arranged circumferentially around the intermediate ring such that each compliance mechanism is coupled between a respective protrusion of the plurality of protrusions and a respective slot of the plurality of slots.
18. The cam phasing system of claim 17 , wherein when the intermediate ring is rotated relative to the spider rotor, the first end of the spring of each compliance mechanism is engaged by the respective slot so as to be biased toward the second end.
19. The cam phasing system of claim 18 , wherein the biasing applies a force onto the respective protrusion via the coil portion of the spring, thereby applying the force from the intermediate ring to the spider rotor.
20. The cam phasing system of claim 12 , wherein the compliance mechanism includes a plurality of compliance mechanisms.