Variable camshaft

Abstract

A variable camshaft includes a base shaft, an axially movable structure, and an actuator. The axially movable structure includes a plurality of lobe packs and at least one barrel cam defining a control groove having an engagement region, a first shift region, a balancing region, a second shift region and a disengagement region. The actuator includes at least one pin operatively configured to move relative to the actuator body between a retracted position and an extended position into the control groove. The axially movable structure moves axially relative to the base shaft the pin is in the extended position and is at least partially disposed in one of the first or second shift regions of the control groove.

What is claimed is: 
     
         1 . A variable camshaft comprising:
 a base shaft;   an axially movable structure mounted on the base shaft, the axially movable structure being axially movable relative to the base shaft and being rotationally fixed to the base shaft, wherein the axially movable structure includes a plurality of lobe packs and at least one barrel cam defining a control groove having an engagement region, a first shift region, a balancing region, a second shift region and a disengagement region having a disengagement catch wall;   an actuator including an actuator body and at least one pin movably coupled to the actuator body, the at least one pin being configured to move relative to the actuator body between a retracted position and an extended position; and   wherein the axially movable structure is configured to move axially relative to the base shaft when the base shaft rotates about a longitudinal axis and the at least one pin is in the extended position and at least partially disposed in one of the first or second shift regions of the control groove.   
     
     
         2 . The variable camshaft as defined in  claim 1  wherein the balancing region is defined in the control groove between the first and second shift regions. 
     
     
         3 . The variable camshaft as defined in  claim 2  wherein the at least one pin is operatively configured to be axially stationary in the balancing region. 
     
     
         4 . The variable camshaft as defined in  claim 3  wherein the first shift region defines a first push wall operatively configured to engage with the at least one pin thereby moving the axially moveable structure along the base shaft. 
     
     
         5 . The variable camshaft as defined in  claim 4  wherein the balancing region defines an outer catch wall operatively configured to engage with the pin upon impact, the outer catch wall having a thickness greater than the thickness of the disengagement catch wall. 
     
     
         6 . The variable camshaft as defined in  claim 4  wherein the second shift region defines a second push wall operatively configured to engage with the at least one pin thereby moving the axially moveable structure along the base shaft. 
     
     
         7 . The variable camshaft as defined in  claim 6  wherein a first entry area is defined where the engagement region transitions into the first shift region. 
     
     
         8 . The variable camshaft as defined in  claim 7  wherein a second entry area is defined where the balancing region transitions into the second shift region. 
     
     
         9 . The variable camshaft as defined in  claim 8  wherein the outer catch wall is operatively configured to engage with the at least one pin in order to stop the axial movement of the axially moveable structure relative to the base shaft while the pin travels straight through the balancing region. 
     
     
         10 . A variable camshaft comprising:
 a base shaft;   an axially movable structure mounted on the base shaft, the axially movable structure being axially movable relative to the base shaft and being rotationally fixed to the base shaft, wherein the axially movable structure includes at least one barrel cam defining a control groove having a first shift region, a balancing region having an outer catch wall, a second shift region, and a disengagement region having a disengagement catch wall;   an actuator including an actuator body and at least one pin movably coupled to the actuator body, the at least one pin being configured to move relative to the actuator body between a retracted position and an extended position; and   wherein the axially movable structure is configured to move axially relative to the base shaft when the base shaft rotates about a longitudinal axis and the at least one pin is in the extended position and at least partially disposed in one of the first or second shift regions of the control groove.   
     
     
         11 . The variable camshaft as defined in  claim 10  wherein the balancing region is defined in the control groove between the first and second shift regions, the balancing having an outer catch wall thickness which is greater than a thickness of the disengagement catch wall. 
     
     
         12 . The variable camshaft as defined in  claim 11  wherein the at least one pin is operatively configured to be axially stationary in the balancing region. 
     
     
         13 . The variable camshaft as defined in  claim 11  wherein the first shift region defines a first push wall operatively configured to engage with the at least one pin thereby moving the axially moveable structure along the base shaft. 
     
     
         14 . The variable camshaft as defined in  claim 13  wherein the disengagement region of the control groove defines a disengagement catch wall. 
     
     
         15 . The variable camshaft as defined in  claim 14  wherein the second shift region defines a second push wall operatively configured to engage with the at least one pin thereby moving the axially moveable structure further along the base shaft. 
     
     
         16 . The variable camshaft as defined in  claim 15  wherein the outer catch wall and the disengagement catch wall are operatively configured to engage with the at least one pin in order to stop the axial movement of the axially moveable structure relative to the base shaft.