Abstract:
A camshaft assembly in which a bearing ( 49 ) includes a first passage ( 18 ) for introducing makeup oil to the phaser and a second passage ( 52 ) for controlling spool ( 20 ) position and lock pin ( 42 ) position. In an alternative embodiment the bearing ( 49 ) is replaced by pieces on the outer shaft and bearings. The pieces on the outer shaft ( 149, 150 ) house the advance and retard annuluses and ports in the inner and outer shafts. A first bearing ( 147 ) provides makeup fluid to the phaser and a second bearing ( 151 ) provides fluid for controlling the position of the spool and the lock pin position.

Description:
REFERENCE TO RELATED APPLICATIONS 
       [0001]    This application claims one or more inventions which were disclosed in Provisional Application No. 61/098,289, filed Sep. 19, 2008, entitled “CAM TORQUE ACTUATED PHASER USING BAND CHECK VALVES BUILT INTO A CAMSHAFT OR CONCENTRIC CAMSHAFTS” and in Provisional Application No. 61/098,274, filed Sep. 19, 2008, entitled, “PHASER BUILT INTO A CAMSHAFT OR CONCENTRIC CAMSHAFTS”. The benefit under 35 USC §119(e) of the United States provisional application is hereby claimed, and the aforementioned applications are hereby incorporated herein by reference. 
     
    
     BACKGROUND OF THE INVENTION 
       [0002]    1. Field of the Invention 
         [0003]    The invention pertains to the field of cam timing. More particularly, the invention pertains to a can torque actuated phaser using band check valves built into a camshaft or concentric camshafts. 
         [0004]    2. Description of Related Art 
         [0005]    Cam in cam systems are well know in the prior art. In prior art cam in cam systems, the camshaft has two shafts, one positioned inside of the other. 
       SUMMARY OF THE INVENTION 
       [0006]    A camshaft assembly for an internal combustion engine comprising: a hollow outer shaft with annuluses along a length of the shaft; an inner shaft having ports along a length of the inner shaft and forming a bore at one end of the inner shaft; the inner shaft received within the hollow outer shaft, such that the ports along the length of the inner shaft are aligned with the annuluses along the length of the outer shaft and cam lobes. The assembly also includes a phaser comprising: a housing an outer circumference for accepting a drive force; a rotor coaxially located within the housing, the housing and the rotor defining at least one vane separating a chamber in the housing into advance and retard chambers, the vane being capable of rotation to shift the relative angular position of the housing and the rotor; and a control valve received within the bore of the inner shaft comprising a spool with a plurality of metered slots; at least one bearing adjacent to the second cam lobe and the housing of the phaser on the outer shaft having a first passage connected to a pressurized source for providing makeup oil to the phaser and a second passage in fluid communication with a valve for controlling the position of a spool and state of the lock pin. 
         [0007]    The camshaft assembly may be used for a multiple cylinder engine or a single cylinder engine. In single cylinder engines, at least one cam lobe is directly attached or hard pressed to the outer shaft and at least one other cam lobe is directly attached or hard pressed to the inner shaft. 
         [0008]    In multiple cylinder engines, the outer shaft is hollow with multiple slots (not shown) that run perpendicular to the axis of rotation and has a sprocket attached to the outside of the outer shaft. Inside the hollow outer shaft is a hollow inner shaft with multiple holes (not shown) that run perpendicular to the length of the shaft. A first set of cam lobes are rigidly attached to the outer shaft and a second set of cam lobes are free to rotate and placed on the outer shaft with a clearance fit. The second set of cam lobes are positioned over slots (not shown) on the outer shaft and are controlled by the inner shaft through a mechanical connection (not shown). 
         [0009]    In an alternative embodiment the bearing is replaced by thrust caps and bearings on the outer shaft. The thrust caps house the advance and retard annuluses and ports in the inner and outer shafts. A first bearing provides makeup fluid to the phaser and a second bearing provides fluid for controlling the position of the spool and the lock pin position. Alternatively, the thrust cap may be a bearing, part of the back plate of the phaser, or any part on the outer shaft. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWING 
         [0010]      FIG. 1  shows a first embodiment of the present invention. 
           [0011]      FIG. 2  shows an exploded view of the first embodiment of the present invention. 
           [0012]      FIG. 3  shows a sectional view of the phaser of the first embodiment of the present invention. 
           [0013]      FIG. 4  shows another sectional view of the phaser of the first embodiment of the present invention with the control valve moving towards a fully forward position. 
           [0014]      FIG. 5  shows a cross-section of  FIG. 4  along line S-S with the control valve moving towards a fully forward position. 
           [0015]      FIG. 6  shows a cross-section of  FIG. 4  alone line U-U with the control valve moving towards a fully forward position. 
           [0016]      FIG. 7  shows a sectional view of the first embodiment of the present invention with the control valve moving towards a fully back position. 
           [0017]      FIG. 8  shows a cross-section of  FIG. 7  along line S-S with the control valve moving towards a fully back position. 
           [0018]      FIG. 9  shows a cross-section of  FIG. 7  along line U-U with the control valve moving towards a fully back position. 
           [0019]      FIG. 10  shows a sectional view of the first embodiment of the present invention with the control valve in the mid position. 
           [0020]      FIG. 11  shows a cross-section of  FIG. 10  along line S-S with the control valve in mid position. 
           [0021]      FIG. 12  shows a cross-section of  FIG. 10  along line U-U with the control valve in mid position. 
           [0022]      FIG. 13  shows an exploded view of the second embodiment of the present invention. 
           [0023]      FIG. 14  shows another sectional view of the phaser of the second embodiment of the present invention with the control valve moving towards a fully forward position. 
           [0024]      FIG. 15  shows a cross-section of  FIG. 14  along line W-W with the control valve moving towards a fully forward position. 
           [0025]      FIG. 16  shows a cross-section of  FIG. 14  along line V-V with the control valve moving towards a fully forward position. 
           [0026]      FIG. 17  shows a sectional view of the second embodiment of the present invention with the control valve moving towards a fully back position. 
           [0027]      FIG. 18  shows a cross-section of  FIG. 17  along line W-W with the control valve moving towards a fully back position. 
           [0028]      FIG. 19  shows a cross-section of  FIG. 17  along line V-V with the control valve moving towards a fully back position. 
           [0029]      FIG. 20  shows a sectional view of the second embodiment of the present invention with the control valve in the mid position. 
           [0030]      FIG. 21  shows a cross-section of  FIG. 20  along line W-W with the control valve in mid position, 
           [0031]      FIG. 22  shows a cross-section of  FIG. 20  along line V-V with the control valve in mid position. 
           [0032]      FIG. 23  shows an exploded view of an alternate embodiment of the present invention 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0033]      FIGS. 1-12  show a camshaft assembly  40  attached to a phaser  70  of a first embodiment of the present invention. The camshaft assembly  40  has an inner shaft  4  and an outer shaft  2 . 
         [0034]    The camshaft assembly  40  may be for a multiple cylinder engine or a single cylinder engine. 
         [0035]    For a multiple cylinder engine, the outer shaft  2  is hollow with multiple slots (not shown) that run perpendicular to the axis of rotation and has a sprocket  14  attached to the outside of the outer shaft  2 . Inside the hollow outer shaft  2  is a hollow inner shaft  4  with multiple holes (not shown) that run perpendicular to the length of the shaft. A first set of cam lobes  6  are rigidly attached to the outer shaft  2  and a second set of cam lobes  8  are free to rotate and placed on the outer shaft  2  with a clearance fit. The second set of cam lobes  8  are positioned over slots (not shown) on the outer shaft  2  and are controlled by the inner shaft  4  through a mechanical connection (not shown). 
         [0036]    For single cylinder engines, the outer shaft  2  is hollow and has a sprocket  14  attached to the outside of the outer shaft  2 . Inside the hollow outer shaft  2  is a hollow inner shaft  4 . At least one cam lobe  6  is directly attached or hard pressed to the outer shaft and at least one other cam lobe  8  is directly attached or hard pressed to the inner shaft  4 . At one end of the camshaft assembly, the rotor  10  of the phaser  70  is rigidly attached to the inner shaft  4 . 
         [0037]    Internal combustion engines have employed various mechanisms to vary the angle between the camshaft and the crankshaft for improved engine performance or reduced emissions. The majority of these variable camshaft timing (VCT) mechanisms use one or more “vane phasers” on the engine camshaft (or camshafts, in a multiple-camshaft engine). In most cases, the phasers have a rotor  10  with one or more vanes  10   a , mounted to the end of the camshaft assembly  40 , surrounded by or coaxially located within the housing  12 . The housing  12  and the rotor  10  form chambers in which the vanes  10   a  fit, dividing the chambers into advance chambers  3  and retard chambers  5 . The vane  10   a  is capable of rotation to shift the relative angular position of the housing  12  and the rotor  10 . It is possible to have the vanes  10   a  mounted to the housing  12 , and the chambers in the rotor  10 , as well. A portion of the housing&#39;s outer circumference forms the sprocket  14 , pulley or gear accepting drive force through a chain, belt, or gears, usually from the crankshaft, or possible from another camshaft in a multiple-cam engine. Front end plate  43  is bolted to the front side of the housing  12 . The back plate  41  is formed as part of the housing  12  and sprocket. Alternatively, as shown in  FIG. 23 , a separate back plate  41  may be bolted to the backside of the housing  12 . A vent  43   a  is present in the front end plate  43  and is aligned with the control valve  21  of the phaser  70 . 
         [0038]    The phaser  70  adjusts the phase of the outer and inner shafts  2 ,  4  relative to each other. The end of the inner shaft  4  of the camshaft assembly  40  has a bore  4   c  that forms a sleeve for receiving the spool  20  of the control valve  21  of the phaser  70 . The spool  20  has a first end with a recess  20   a  that receives a spring  23  and second end  20   e  that that engages an alignment plug  50  present within the inner shaft  4 , preventing the spool  20 , from rotating relative to the inner shaft  4 . The spring  23  biases the spool  20  in a first direction away from the front plate  43 . The spool  20  also has metering slots  20   b ,  20   c ,  20   d  that aid in directing fluid to the advance and retard chambers  3 ,  5  and to a lock pin  42 . 
         [0039]    Between the first cam lobe  6  and the back end plate  41  is a first wide bearing  49  and adjacent to the second cam lobe  8  is second bearing  51 . Within the first wide bearing  49  are two main passages  18 ,  52  that lead to aligned ports and annuluses in the outer and inner shafts  2 ,  4 . The annuluses  28 ,  30 ,  32  in the outer shaft  2  are aligned with the ports  29 ,  31 ,  27  on the inner shaft  4  and the metered slots  20   b ,  20   c ,  20   d  of the spool  20  depending on the position of the spool  20  within the inner shaft  4 . The first passage  18  in the first wide bearing  49  supplies fluid to the phaser  70  and feeds the bearing  49 . The first passage  18  is in fluid communication with a groove  19  in the first wide bearing  49  that is aligned with three annuluses  28 ,  30 ,  32  in the outer shaft  2 , an advance annuluses  28  in the outer shaft  2  leading to an advance port  29  in the inner shaft  4 , a supply or common annulus  30  in the outer shaft  2  leading to a central port  31  in the inner shaft  4 , and a retard annulus  32  in the outer shaft  2  leading to a retard port  27  in the inner shaft  4 . The advance annulus  28 , the retard annulus  30 , and the first passage  18  each have a check valve present  34 ,  36 ,  22  respectively. The check valves  34 ,  36 ,  22  are preferably band check valves or disc check valves, although other types of check valves may also be used. 
         [0040]    The second passage  52  in the first wide bearing  49  supplies fluid that controls the lock pin  42  and biases the position of the spool  20  of the control valve  21  in a second direction, towards the front plate  43 , via a valve  62 . The valve  62  may be an on/off valve with a constant source of pressurized fluid or an infinitely variable valve. 
         [0041]    The lock pin  42  is present within a bore  10   b  in the rotor  10  of the phaser. The lock pin  42  includes a lock pin body  46  and a spring  43 . The spring  43  biases the lock pin body  46  towards a locked position in which the lock pin body  46  engages a recess  53  in the housing  12  and the housing  12  is locked relative to the rotor  10 . In an unlocked position, fluid biases the lock pin body  46  away from the recess  53  in the housing  12  and against the spring  43 . It should be noted that while the lock pin  42  is shown in the rotor  10  and engages the housing  12  to lock the housing  12  relative to the rotor  10 , the lock pin  42  may be present in the housing  12  and engage the rotor  10 . 
         [0042]      FIGS. 4-6  show the control valve moving towards a fully forward position. Fluid from a pressurized source of fluid moves through valve  62  to the second passage  52  in the first wide bearing  49  to a groove  60  formed within the outer shaft  2  between the outer shaft  2  and the inner shaft  4 . From the groove  60 , fluid flows through a port  4   a  in the inner shaft  4  into metered slot  20   d  that extends a substantial length of the spool  20 , however not the entire length of the spool, with one end of the metered slot  20   d  open to chamber  64  formed between the second end  20   e  of the spool  20  and the alignment plug  50  and the other end of the metered slot  20   d  is aligned with passage  47  in the rotor  10  leading to the lock pin  42 . The fluid pressure of the fluid supplied to chamber  64  is greater than the spring force of spring  23  and the fluid in chamber  64  biases the second end  20   e  of the spool  20  towards the front plate  43  of the phaser  70 , aligning the metered slot  20   d  with lock pin passage  47  in the rotor  10  and allowing fluid from the valve  62  to bias the lock pin  42  to an unlocked position. 
         [0043]    With the spool  20  moving towards the fully forward position, the metering slot  20   c  is aligned with the advance annulus  28  and port  29  and the common annulus  30  and port  31 , and advance chamber annulus portion  37   a  connecting the metered slot  20   c  to the advance passage  33  leading to the advance chamber  3 . With the spool  20  moving towards the fully forward position, metering slot  20   b  is aligned with the retard annulus  32  and port  27 , and retard chamber annulus portion  37   b  connecting the metered slot  20   b  to the retard passage  35  leading to the retard chamber  5 . 
         [0044]    With the spool  20  moving towards the fully forward position, fluid from the advance chamber  3  flows through advance passage  33  in the rotor  10  through the advance chamber annulus portion  37   a  in the inner shaft  4  to the metered slot  20   c  on the spool  20  to the advance port  29  and the common line port  31 . Fluid is prevented from entering the advance annulus  28  by check valve  34 . From the common line port  31 , fluid enters the common annulus  30  and groove  19  leading to the retard annulus  32  and port  27 . From the retard port  27 , fluid enters metered slot  20   b  and the retard chamber annulus portion  37   b  to the retard passage  35  leading to the retard chamber  5 , moving the vane  10   a  in the direction shown by the arrow in  FIG. 4 . Fluid is prevented from exiting the retard chamber  5  by the retard check valve  36 . Fluid is prevented from flowing back to the pressurized source (not shown) through the first passage  18  by check valve  22 . Fluid is supplied to phaser  70  by inlet line  18  from a pressurized source (not shown) to make up for leakage only. 
         [0045]      FIGS. 7-9  show the control valve  21  moving towards a fully back position. Valve  62  is moved to a vent position, and fluid present in the bore  10   b  housing the lock pin  42 , the metered slot  20   d  and the chamber  64  formed between the second end  20   e  of the spool  20  and the alignment plug  50  vent to sump. With the fluid from the bore  10   b  housing the lock pin  42  draining to sump, the lock pin spring  43  biases the lock pin body  46  towards engagement with the recess  53  in the housing  12 , and when the lock pin  42  is alignment with the recess  53  in the housing, the lock pin is moved to a locked position in which the housing  12  is locked relative to the rotor  10 . With the fluid in the chamber  64  formed between the second end  20   e  of the spool  20  and the alignment plug  50  venting to sump, the force of the spring  23  is greater than the force of the fluid in chamber  64  on the second end of the spool, and the spool moves away from, the front plate  43 . 
         [0046]    With the spool  20  moving towards the fully back position, the metering slot  20   c  is aligned with the advance annulus  28  and port  29  and advance chamber annulus portion  37   b  connecting the metered slot  20   c  to the advance passage  33  leading to the advance chamber  3 . Additionally, the metered slot  20   b  is aligned with the retard annulus  32  and port  27  and the common annulus  30  and port  31  and retard chamber annulus portion  37   b  connecting the metered slot  20   b  to the retard passage  35  leading to the retard chamber  5 . 
         [0047]    With the spool  20  moving towards the fully back position, fluid from the retard chamber  5  flows through retard passage  35  in the rotor  10  through retard chamber annulus portion  37   b  in the inner shaft  4  to the metered slot  20   b  on the spool  20  to the retard port  27  and the common line port  31 . Fluid is prevented from entering the retard annulus  32  by check valve  36 . From the common line port  31 , fluid enters the common annulus  30  and groove  19  leading to the advance annulus  28  and a port  29 . From the advance port  29 , fluid enters metered slot  20   c  and port  29  to the advance passage  33  leading to the advance chamber  3 , moving the vane  10   a  in the direction shown by the arrow in  FIG. 7 . Fluid is prevented from exiting the advance chamber  3  by the advance check valve  34 . Fluid is prevented from flowing back to the pressurized source (not shown) through the first passage  18  by check valve  22 . Fluid is supplied to phaser by inlet line  18  from a pressurized source (not shown) to make up for leakage only. 
         [0048]      FIGS. 10-12  shows a mid position. In the mid position, the force on the first end of the spool  20  by the spring  23  equals the force of the fluid in chamber  64  on the second end  20   e  of the spool  20 , such that the metered slot  20   c  is open to the advance annulus  28  and port  29  and advance chamber annulus portion  37   a  leading to the advance passage  33  and the advance chamber  3  and metered slot  20   b  is open to the retard annulus  32  and port  27  and retard chamber annulus portion  37   b  leading to the retard passage  35  and the retard chamber  5 . Makeup oil is supplied to the phaser  70  from a pressurized source (not shown) to make up for leakage and enters line  18  in the first wide bearing  49 . From the inlet line  18 , fluid enters groove  19  within the first wide bearing  49  and enters the advance annulus  28 , through the advance check valve  34  and the advance port  29  to metered slot  20   c  of the spool  20  which leads to the advance chamber annulus portion  37   a  and advance passage  33  leading to the advance chamber  3 . The fluid from groove  19  also enters the retard annulus  32  through the retard check valve  36  and the retard port  27  to the metered slot  20   b  of the spool  20  which leads to the retard chamber annulus portion  37   b  and the retard passage  35  leading to the retard chamber  5 . Fluid is prevented from exiting the common line annulus  30  or port  31  by the spool  20 . 
         [0049]    Fluid is also directed through the second passage  52  in the first wide bearing  49  to a groove  60  formed within the outer shaft  2  between the outer shaft  2  and the inner shaft  4  by valve  62 . From the groove  60 , fluid flows through an annulus  4   a  in the inner shaft  4  into metered slot  20   d  that extends a substantial length of the spool  20 , however not the entire length of the spool, with one end of the metered slot  20   d  open to chamber  64  formed between the second end  20   e  of the spool  20  and the alignment plug  50  and the other end aligned with passage  47  in the rotor  10  leading to the lock pin  42 . With the spool in the mid position, fluid flows from the valve  62 , through groove  60  and metered slot  20   d  to passage  47  in the rotor  10 , biasing the lock pin body  46  against the lock pin spring  44  moving the lock pin  42  to an unlocked position. 
         [0050]      FIGS. 13-22  show a camshaft assembly  140  attached to a phaser of a second embodiment of the present invention. The camshaft assembly  140  has an inner shaft  4  and an outer shaft  2 . The camshaft assembly of the second embodiment may be for a multiple cylinder engine or a single cylinder engine. 
         [0051]    For a multiple cylinder engine, the outer shaft  2  is hollow with multiple slots (not shown) that run perpendicular to the axis of rotation and has a sprocket  14  attached to the outside of the outer shaft  2 . Inside the hollow outer shaft  2  is a hollow inner shaft  4  with multiple holes (not shown) that run perpendicular to the length of the shaft. A first set of cam lobes  6  are rigidly attached to the outer shaft  2  and a second set of cam lobes  8  are free to rotate and placed on the outer shaft  2  with a clearance fit. The second set of cam lobes are positioned over slots (not shown) on the outer shaft  2  and are controlled by the inner shaft  4  through a mechanical connection (not shown). 
         [0052]    For single cylinder engines, the outer shaft  2  is hollow and has a sprocket  14  attached to the outside of the outer shaft  2 . Inside the hollow outer shaft  2  is a hollow inner shaft  4 . At least one cam lobe  6  is directly attached or hard pressed to the outer shaft and at least one other cam lobe  8  is directly attached or hard pressed to the inner shaft  4 . At one end of the camshaft assembly, the rotor  10  of the phaser  70  is rigidly attached to the inner shaft  4 . 
         [0053]    Internal combustion engines have employed various mechanisms to vary the angle between the camshaft and the crankshaft for improved engine performance or reduced emissions. The majority of these variable camshaft timing (VCT) mechanisms use one or more “vane phasers” on the engine camshaft (or camshafts, in a multiple-camshaft engine). In most cases, the phasers have a rotor  10  with one or more vanes  10   a , mounted to the end of the camshaft assembly, surrounded by or coaxially located within the housing  8 . The housing and the rotor form chambers in which the vanes  10   a  fit, dividing the chambers into advance chambers  3  and retard chambers  5 . The vane  10   a  is capable of rotation to shift the relative angular position of the housing  12  and the rotor  10 . It is possible to have the vanes  10   a  mounted to the housing  12 , and the chambers in the rotor  10 , as well. A portion of the housing&#39;s outer circumference forms the sprocket  14 , pulley or gear accepting drive force through a chain, belt, or gears, usually from the crankshaft, or possible from another camshaft in a multiple-cam engine. Front end plate  43  is bolted to the front side of the housing  12 . The back plate  41  is formed as part of the housing  12  and sprocket. Alternatively, as shown in  FIG. 23 , a separate back plate  41  may be bolted to the backside of the housing  12 . A vent  43   a  is present in the front end plate  43  and is aligned with the control valve  20  of the phaser  70 . 
         [0054]    The phaser  70  adjusts the phase of the shafts  2 ,  4  relative to each other. The end of the inner shaft  4  of the camshaft assembly  140  has a bore  4   c  that forms a sleeve for receiving the spool  20  of the control valve  21  of the phaser. The spool  20  has a first end with a recess  20   a  that receives a spring  23  and a second end  20   e  that engages an alignment plug  50  present within the inner shaft  4 , preventing the spool  20  from rotation. The spring  23  biases the spool  20  in a first direction away from the front plate  43 . The spool  20  also has metering slots  20   b ,  20   c ,  20   d  that aid in direction fluid to the advance and retard chambers  3 ,  5  and to a lock pin  42 . It should be noted that in this embodiment the spool and the metered slots are longer than the spool in the first embodiment so that the ports and annuluses in the thrust caps  149 ,  150  are aligned with appropriate metered slots in the spool. 
         [0055]    Between the first cam lobe  6  and the back end plate  41  are a first thrust cap  149  immediately adjacent to the back end plate  41 , a first bearing adjacent to the first thrust cap  149  and then a second thrust cap  150  adjacent to the first bearing  147  and the first cam lobe  6 . A second bearing  151  is present between the first cam lobe  6  and the second cam lobe  8 . 
         [0056]    Within in the first bearing  147  is a passage  118  that supplies fluid to the phaser  70  and feeds the bearing  147 . The first passage  118  is in fluid communication with a common line annulus  130  and a common line port  131  in the outer shaft  2  that leads to an annulus  119  in the outer shaft  2 . The annulus  119  in the outer shaft  2  extends to a second advance port  128   b  within the outer shaft  2  in fluid communication with a chamber  150   a  within the second thrust cap  150  and to a second retard port  132   b  within the outer shaft  2  in fluid communication with a chamber  149   a  within the first thrust cap  149 . Also within the chamber  150   a  of the second thrust cap  150  is a first advance port  128   a  and a first advance annulus  129   a  of the outer shaft  2  aligned with a third advance port  129  on the inner shaft  4  which is in fluid communication with metered slot  20   c  of the spool  20 . Within the chamber  149   a  of the first thrust cap  149  is a first retard port  132   a  and a first retard annulus  127   a  of the outer shaft  2  aligned with a third retard port  127  on the inner shaft  4  which is in fluid communication with metered slot  20   b  of the spool  20 . The first advance annulus  129   a  and the first retard annulus  127   a  each have a check valve  134 ,  136  present. An inlet check valve  122  within fluid passage  118  may also be present. The check valves  134 ,  136 ,  122  are preferably band check valves or disc check valves, although other types of check valves may also be used. 
         [0057]    Within the second bearing  151  is a second passage  152  that supplies fluid that controls the lock pin  42  and biases the position of the spool  20  of the control valve  21  in a second direction, towards the front plate  43 , via a valve  62 . The valve  62  may be an on/off valve with a constant source of pressurized fluid or an infinitely variable valve. 
         [0058]    The lock pin  42  is present within a bore  10   b  in the rotor  10  of the phaser. The lock pin includes a lock pin body  46  and a spring  44 . The spring  44  biases the lock pin body  46  towards a locked position in which the lock pin body  46  engages a recess  53  in the housing  12  and the housing  12  is locked relative to the rotor  10 . In an unlocked position, fluid biases the lock pin body  46  away from the recess  53  in the housing  12  and against the spring  44 . It should be noted that while the lock pin  42  is shown in the rotor  10  and engages the housing  12  to lock the housing  12  relative to the rotor  10 , the lock pin  42  may be present in the housing  12  and engage the rotor  10 . 
         [0059]      FIGS. 14-16  show the control valve moving towards a fully forward position. Fluid from a pressurized source of fluid moves through valve  62  to the second passage  52  in the second bearing  151  to an annulus  160  formed within the outer shaft  2  between the outer shaft  2  and the inner shaft  4 . From the annulus  160 , fluid flows through a port  4   a  in the inner shaft  4  into metered slot  20   d  that extends a substantial length of the spool  20 , however not the entire length of the spool, with one end of the metered slot  20   d  open to chamber  64  formed between the second end  20   e  of the spool  20  and the alignment plug  50  and the other end aligned with passage  4 ′ 7  in the rotor leading to the lock pin  42 . The fluid pressure of the fluid supplied to chamber  64  is greater than the spring force of spring  23  and the fluid in chamber  64  biases the second end  20   e  of the spool  20  towards the front plate  43  of the phaser  70 , aligning the metered slot  20   d  with lock pin passage  47  in the rotor  10  and allowing fluid from the valve  62  to bias the lock pin  42  to an unlocked position. 
         [0060]    With the spool  20  moving towards the fully forward position, the metering slot  20   c  is aligned with the third advance port  129 , the first advance annulus  129   a , and the first advance port  128   a , and the advance chamber annulus  37   a  connecting the metered slot  20   c  to the advance passage  33  leading to the advance chamber  3 , and the common port  131  and common annulus  130 . With the spool  20  moving towards the fully forward position, metering slot  20   b  is aligned with the third retard port  127 , the first retard annulus  127   a , and the first retard port  132   a , and the retard chamber annulus  37   b , connecting the metered slot  20   b  to the retard passage  35  leading to the retard chamber  5 . 
         [0061]    With the spool  20  moving towards the fully forward position, fluid from the advance chamber  3  flows through advance passage  33  in the rotor  10  through advance chamber annulus portion  37   a  in the inner shaft  4  to the metered slot  20   c  on the spool  20  to the third advance port  129  and the common port  131 . Fluid is prevented from entering the first advance port  128   a  by check valve  134 . From the common line port  131 , fluid enters the common annulus  130  and annulus  119 . From the annulus  119 , fluid flows through the second retard port  132   b , into chamber  149   a  of the first thrust cap  149  and through the first retard port  132   a  and first retard annulus  127   a  and check valve  136 , through the third retard port  127  and into metered slot  20   b . From the metered slot  20   b , fluid flows into the retard chamber annulus  37   b  in the inner shaft  4  to the retard passage  35  in the rotor  10  to the retard chamber  5 , moving the vane  10   a  in the direction show by the arrow in  FIG. 14 . Fluid is prevented from exiting the retard chamber  5  by the retard check valve  136 . Fluid is prevented from flowing back to the pressurized source through inlet passage  118  by check valve  22 . Fluid from annulus  119  that flows through the third advance port  129 , through the first advance annulus  129   a  and check valve  134  and the first advance port  128   a  and into the chamber  150   a  of the second thrust cap  150  will flow into the metered slot  20   c  leading back to the annulus  119  and to the retard chamber  5 . Fluid is supplied to the phaser by inlet line  118  from a pressurized source (not shown) to make up for leakage only. 
         [0062]      FIGS. 17-19  show the control valve  62  moving towards a fully back position. Valve  62  is moved to a vent position, and fluid present in the bore  10   b  housing the lock pin  42 , the metered slot  20   d  and the chamber  64  formed between the second end  20   e  of the spool  20  and the alignment plug  50  vent to sump. With the fluid from the bore  10   b  housing the lock pin  42  draining to sump, the lock pin spring  43  biases the lock pin body  46  towards engagement with the recess  53  in the housing  12 , and when the lock pin  42  is alignment with the recess  53  in the housing, the lock pin  42  is moved to a locked position in which the housing  12  is locked relative to the rotor  10 . With the fluid in the chamber  64  formed between the second end  20   e  of the spool  20  and the alignment plug  50  venting to sump, the force of the spring  23  is greater than the force of the fluid in the chamber  64  on the second end  20   e  of the spool  20 , and the spool  20  moves away from the front plate  43 . 
         [0063]    With the spool moving towards the fully back position, the metering slot  20   b  is aligned with the third retard port  127 , the first retard annulus  127   a , and the first retard port  132   a , and the retard chamber annulus  37   b  connecting the metered slot  20   b  to the retard passage  35  leading to the retard chamber  5 , and the common port  131  and common annulus  130 . With the spool  20  moving towards the fully back position, metering slot  20   c  is aligned with the third advance port  129 , the first advance annulus  129   a , and the first advance port  128   a  and advance chamber annulus  37   a , connecting the metered slot  20   c  to the advance passage  33  leading to the advance chamber  3 . 
         [0064]    With the spool  20  moving towards the fully back position, fluid from the retard chamber  5  flows through retard passage  35  in the rotor  10  through retard chamber annulus portion  37   b  in the inner shaft  4  to the metered slot  20   b  on the spool  20  to the third retard port  127   a  and the common port  131 . Fluid is prevented from entering the first retard annulus  127   a  by check valve  136 . From the common line port  131 , fluid enters the common annulus  130  and annulus  119 . From the annulus  119 , fluid flows through the second advance port  128   b , into chamber  150   a  of the second thrust cap  150  and through the first advance port  128   a , into the first advance annulus  129   a , through check valve  134 , through the third advance port  129  and into metered slot  20   c . From the metered slot  20   c , fluid flows into the advance chamber annulus  37   a  in the inner shaft  4  to the advance passage  37  in the rotor  10  to the advance chamber  3 , moving the vane  10   a  in the direction show by the arrow in  FIG. 17 . Fluid is prevented from exiting the advance chamber  3  by the advance check valve  134 . Fluid is prevented from flowing back to the pressurized source through inlet passage  118  by check valve  122 . Fluid from annulus  119  that flows through the third retard port  127 , through the first retard annulus  127   a  and check valve  136  and the first retard port  132   a  and into chamber  149   a  of the first thrust cap  149  will flow through the retard check valve  136  and into the metered slot  20   b  leading back to the annulus  119  and to the retard chamber  3 . Fluid is supplied to the phaser by inlet line  118  from a pressurized source (not shown) to make up for leakage only. 
         [0065]      FIGS. 20-22  show a mid position. In the mid position, the force on the first end of the spool  20  by the spring  23  equals the force of the fluid in chamber  64  on the second end  20   e  of the spool  20 , such that the metered slot  20   c  is open to the first advance port  128   a , the first advance annulus  129   a  and the third advance port  129  and advance chamber annulus portion  37   a  leading to the advance passage  33  and the advance chamber  3  and metered slot  20   b  is open to the first retard port  132   a , the first retard port annulus  127   a  and retard port  127  and retard chamber annulus portion  37   b  leading to the retard passage  35  and the retard chamber  5 . Makeup oil is supplied to the phaser  70  from a pressurized source (not shown) to make up for leakage and enters line  118  in the first bearing  147 . From the inlet line  118 , fluid enters annulus  119  formed between the outer shaft  2  and the inner shaft  4  and enters the second advance port  128   b  and chamber  150   a  of the second thrust cap  150 , through the first advance port  128   a , the first advance annulus  129   a  and the advance check valve  134  and the advance port  129  to metered slot  20   c  of the spool  20  which leads to the advance chamber annulus portion  37   a  and advance passage  33  leading to the advance chamber  3 . The fluid from annulus  119  between the outer and inner shafts  2 ,  4  also enters the second retard annulus  132   b  and chamber  149   a  of the first thrust cap  149 , through the first retard port  132   a , the first retard annulus  127   a  and the retard check valve  136  and the retard port  127  to the metered slot  20   b  of the spool  20  which leads to the retard chamber annulus portion  37   b  and the retard passage  35  leading to the retard chamber  5 . Fluid is prevented from exiting the common line annulus  130  or port  131  by the spool  20 . 
         [0066]    Fluid is also directed through the second passage  152  in the second bearing  151  to a groove  60  formed within the outer shaft  2  between the outer shaft  2  and the inner shaft  4  by valve  62 . From the groove  60 , fluid flows through an annulus  4   a  in the inner shaft  4  into metered slot  20   d  that extends a substantial length of the spool  20 , however not the entire length of the spool, with one end of the metered slot  20   d  open to chamber  64  formed between the second end  20   e  of the spool  20  and the alignment plug  50  and the other end aligned with passage  47  in the rotor  10  leading to the lock pin  42 . With the spool in the mid position, fluid flows from the valve  62 , through groove  60  and metered slot  20   d  to passage  47  in the rotor  10 , biasing the lock pin body  46  against the lock pin spring  44  moving the lock pin  42  to an unlocked position. 
         [0067]    Alternatively, the thrust caps in the second embodiment may be bearings, part of the back plate of the phaser, or any part on the outer shaft. 
         [0068]    Accordingly, it is to be understood that the embodiments of the invention herein described are merely illustrative of the application of the principles of the invention. Reference herein to details of the illustrated embodiments is not intended to limit the scope of the claims, which themselves recite those features regarded as essential to the invention.