Sliding camshaft assembly

Abstract

A camshaft assembly includes an actuator and an axially moveable structure mounted to a base shaft wherein the axially moveable structure includes a plurality of lobe packs and a cam barrel. The axially movable structure moves along the base shaft in the axial direction along a longitudinal axis of the base shaft, but is rotationally fixed to the base shaft. The barrel cam includes an inner wall and an outer wall which defines a control groove therebetween. The control groove further defines first and second regions wherein the first region includes a fixed narrow control groove width and the second region includes a progressively decreasing control groove width. The actuator shifts the axially moveable structure relative to the base shaft between a first position and a second position. A recess is defined in the outer wall such that the recess is disposed adjacent to the first region.

1 . A camshaft assembly comprising:
 a base shaft extending along a longitudinal axis;   an axially movable structure mounted on the base shaft and being axially movable relative to the base shaft between a first position and a second position via an actuator while also being rotationally fixed to the base shaft, the axially movable structure includes:
 a plurality of lobe packs, each of the plurality of lobe packs including a plurality of 
   cam lobes; and
 a barrel cam having a control groove defined between an inner wall and an outer wall of the barrel cam such that the control groove further includes a first region having a fixed narrow groove width between the inner and outer walls and a second region having an enlarged groove width between the inner wall and the outer walls; and 
 a recess is defined in the outer wall of the barrel cam such that the recess is disposed adjacent to the first region; 
 wherein the recess is defined in the first region of the barrel cam, and 
 wherein the fixed narrow groove and the enlarged groove are aligned circumferentially around the longitudinal axis at an axial position, such that the control groove does not circumferentially overlap with itself. 
   
     
     
         2 . The camshaft assembly of  claim 1  further comprising a sensor configured to align with the axially moveable structure along a first sensor path when the axially moveable structure moves to the first position, and the sensor is configured to align with the axially moveable structure along a second sensor path when the axially moveable structure moves to the second position. 
     
     
         3 . The camshaft assembly as defined in  claim 2  wherein the first sensor path overlays the outer wall and the recess defined in the outer wall. 
     
     
         4 . The camshaft assembly as defined in  claim 3  wherein the second sensor path overlays the control groove and the outer wall. 
     
     
         5 . The camshaft assembly of  claim 4 , further comprising a control module in communication with the actuator and the sensor. 
     
     
         6 . The camshaft assembly of  claim 5 , wherein each lobe pack in the plurality of lobe packs includes a first cam lobe adjacent to a second cam lobe. 
     
     
         7 . The camshaft assembly of  claim 6 , wherein the first cam lobe is configured to engage with an engine valve when the axially moveable structure is in the first position. 
     
     
         8 . The camshaft assembly of  claim 7  wherein the recess and outer wall are configured to communicate to an engine control module via the sensor to detect the first position of the axially movable structure when the recess and the outer wall are aligned with the sensor in a first sensor path. 
     
     
         9 . The camshaft assembly of  claim 8  wherein the control groove and the outer wall are configured to communicate to an engine control module via the sensor to detect the second position of the axially movable structure when control groove and the outer wall are aligned with the sensor in a second sensor path. 
     
     
         10 . An engine assembly, comprising:
 an internal combustion engine including a first cylinder, a second cylinder, a first valve operatively coupled to the first cylinder, and a second valve operatively coupled to the second cylinder;   an engine control module;   a camshaft assembly operatively coupled to the first and second valves, wherein the camshaft assembly includes:
 a base shaft extending along a longitudinal axis, the base shaft being configured to rotate about the longitudinal axis; 
 an axially movable structure being axially movable between a first position and a second position on the base shaft and being rotationally fixed to the base shaft, wherein the axially movable structure further includes; 
 a barrel cam having a control groove defined between an inner wall and an outer wall of the barrel cam, the control groove defining a fixed narrow groove width throughout a first region and an enlarged groove width which progressively varies in at least a portion of a second region of the barrel cam, wherein the fixed narrow groove and the enlarged groove are aligned circumferentially around the longitudinal axis at an axial position, such that the control groove does not circumferentially overlap with itself; and 
 an actuator configured to move the axially movable structure between the first and second positions via the control groove in the barrel cam according to an output signal from the engine control module; and 
 a sensor configured to send a first set of data to the engine control module when the axial moveable structure is a first position and configured to send a second set of data to the engine control module when the axial moveable structure is in the second position, 
 wherein a recess is defined in the outer wall of the barrel cam and is aligned with the sensor when the axially moveable structure is in the first position. 
   
     
     
         11 . The engine assembly of  claim 10  wherein the enlarged groove width of the second region is greater than the fixed narrow groove width of the first region. 
     
     
         12 . The engine assembly of  claim 11 , wherein the axially moveable structure further includes a plurality of lobe packs which are configured to rotate synchronously with the barrel cam when the axially movable structure rotates together with the base shaft. 
     
     
         13 . The engine assembly of  claim 12 , wherein the actuator includes at least one pin configured to move between a retracted and extended positions in response to the output signal from the engine control module. 
     
     
         14 . The engine assembly of  claim 13 , wherein each lobe pack in the plurality of lobe packs includes a first cam lobe being adjacent to a second cam lobe. 
     
     
         15 . The engine assembly of  claim 14  wherein the first cam lobe has a first maximum lobe height, the second cam lobe has a second maximum lobe height, and the first maximum lobe height is different from the second maximum lobe height.