Development of a switching roller finger follower for cylinder deactivation in internal combustion engines

Abstract

A rocker arm includes an outer arm having a first side and a second side, an inner arm positioned between the first side and the second side of the outer arm, a pivot axle pivotally coupling the inner arm and the outer arm at a first end of each of the inner arm and the outer arm, and a latch having a first position and a second position. The latch in the first position pivotally fixes the inner arm and the outer arm at a second end of each of the inner arm and the outer arm, and in the second position allows the inner arm and the outer arm to pivot independently. The latch is responsive to hydraulic pressure in a hydraulic fluid passage to selectively move to other of the first position and the second position. A lost motion spring is coupled to the inner arm.

What is claimed is: 
     
         1 . A rocker arm, comprising:
 an outer arm comprising a first side and a second side;   an inner arm disposed between the first side and the second side of the outer arm;   a pivot axle pivotally coupling the inner arm and the outer arm at a first end of each of the inner arm and the outer arm;   a latch having a first position and a second position, wherein the latch in the first position pivotally fixes the inner arm and the outer arm at a second end of each of the inner arm and the outer arm, and in the second position allows the inner arm and the outer arm to pivot independently;   a first biasing member urging the latch into one of the first position and the second position, a hydraulic fluid passage hydraulically coupled to the latch, and wherein the latch is responsive to hydraulic pressure in the hydraulic fluid passage to selectively move to other of the first position and the second position; and   a lost motion spring operationally coupled to the inner arm.   
     
     
         2 . The rocker arm of  claim 1 , further comprising a hydraulic lash adjuster fluidly coupled to hydraulic fluid passage and mechanically coupled to one of the inner arm and the outer arm. 
     
     
         3 . The rocker arm of  claim 2 , wherein the hydraulic lash adjuster is mechanically coupled to the inner arm. 
     
     
         4 . The rocker arm of  claim 2 , wherein the hydraulic lash adjuster is a dual feed hydraulic lash adjuster. 
     
     
         5 . The rocker arm of  claim 1 , wherein the first side and the second side of the outer arm each comprise a slider pad, the slider pads configured to engage a low lift cam. 
     
     
         6 . The rocker arm of  claim 1 , further comprising a bearing axle mechanically coupled to one of the inner arm and the outer arm, the bearing axle having a bearing roller mounted thereon, and the bearing roller configured to engage a low lift cam. 
     
     
         7 . The rocker arm of  claim 6 , wherein a high lift one of the inner arm and outer arm includes a slider pad engagement surface for the cam, and wherein a low lift one of the inner arm and the outer arm is mechanically coupled to the bearing axle. 
     
     
         8 . The rocker arm of  claim 6 , wherein the bearing axle is mechanically coupled to the inner arm. 
     
     
         9 . The rocker arm of  claim 1 , further comprising the outer arm defining a latch bore therein, wherein the latch is at least partially positioned within the latch bore. 
     
     
         10 . The rocker arm of  claim 1 , the inner arm further defining an inner arm bore wherein the latch in the first position extends into an inner arm bore. 
     
     
         11 . The rocker arm of  claim 1 , the inner arm further defining an engagement slot, wherein the latch in the first position extends into the engagement slot, and wherein the engagement slot and the latch have a contact position only on a vertically upward side of the latch. 
     
     
         12 . The rocker arm of  claim 1 , wherein a high lift one of the inner arm and outer arm includes a slider pad engagement surface for the cam, and wherein a low lift one of the inner arm and the outer arm includes a roller bearing engagement for the cam. 
     
     
         13 . The rocker arm of  claim 1 , wherein the latch comprises a circular cross-section. 
     
     
         14 . The rocker arm of  claim 13 , wherein at least one of the outer arm and the inner arm comprises an arcuate latch seat, wherein the latch in an extended position engages the arcuate latch seat to pivotally fix the inner arm and the outer arm. 
     
     
         15 . A rocker arm, comprising:
 an outer arm comprising a first side and a second side;   an inner arm disposed between the first side and the second side of the outer arm;   a pivot axle pivotally coupling the inner arm and the outer arm at a first end of each of the inner arm and the outer arm;   a latch having a first position and a second position, wherein the latch in the first position pivotally fixes the inner arm and the outer arm at a second end of each of the inner arm and the outer arm, and in the second position allows the inner arm and the outer arm to pivot independently;   a first biasing member urging the latch into one of the first position and the second position, a hydraulic fluid passage hydraulically coupled to the latch, and wherein the latch is responsive to hydraulic pressure in the hydraulic fluid passage to selectively move to other of the first position and the second position;   a lost motion spring operationally coupled to the inner arm; and   a hydraulic lash adjuster fluidly coupled to a hydraulic fluid passage and mechanically coupled to one of the inner arm and the outer arm, wherein the hydraulic lash adjuster is a dual feed hydraulic lash adjuster.   
     
     
         16 . The rocker arm of  claim 15 , wherein the hydraulic lash adjuster is mechanically coupled to the inner arm. 
     
     
         17 . The rocker arm of  claim 15 , wherein the latch comprises a circular cross-section. 
     
     
         18 . The rocker arm of  claim 17 , wherein at least one of the inner arm and the outer arm comprises an arcuate latch seat, wherein the latch in an extended position engages the arcuate latch seat to pivotally fix the inner arm and the outer arm. 
     
     
         19 . The rocker arm of  claim 15 , wherein the inner arm comprises a cam-contacting member to engage a first cam, and wherein the cam-contacting member comprises a slider pad. 
     
     
         20 . The rocker arm of  claim 19 , further comprising the lost motion spring disposed between the first arm and the second arm.