Patent Publication Number: US-9896976-B2

Title: Variable camshaft phaser with a linear actuator for absolute positioning

Description:
FIELD 
     The present disclosure relates to a multi-position camshaft phaser with two one-way wedge clutches. In particular, the two one-way wedge clutches are used to advance and retard the phase of the rotor with respect to the stator. 
     BACKGROUND 
     It is known to use fluid pressure in chambers created by respective portions of a stator and a rotor for a camshaft phaser to maintain and shift a rotational position of the rotor with respect to the stator. This known technique involves complicated hydraulic systems and controls. 
     SUMMARY 
     An example embodiment comprises a variable camshaft phaser, having a stator arranged to receive torque from an engine; a rotor arranged to be non-rotatably connected to a camshaft; a first wedge plate and a second wedge plate radially disposed between the stator and the rotor; a spinner, operatively arranged about a central hub, the spinner having a twisting groove therein; a paddle arranged about the spinner comprising an annular ring having an engagement projection extending outwardly therefrom, the engagement projection having a proximate section and a distal section; the proximate section operatively arranged to engage the twisting groove, and the distal section operatively arranged to engage either the first or second wedge plates; wherein the spinner, paddle, central hub, and engagement projection are operatively arranged to displace the first or the second wedge plate in either an advance mode or in a retard mode; wherein, in the advance mode, the central hub and the spinner are displaced in a first axial direction to enable rotation of the paddle with respect to the rotor, and engage the first wedge plate in a first circumferential direction; and, wherein, in the retard mode, the central hub and the spinner are displaced in a second axial direction, opposite the first axial direction, to enable rotation of the paddle with respect to the rotor, and engage the second wedge plate in a second circumferential direction, opposite the first circumferential direction. 
     Another example embodiment comprises a variable camshaft phaser, having a stator arranged to receive torque from an engine; a rotor arranged to be non-rotatably connected to a camshaft, the rotor including a first and a second circumferentially arranged groove; a first wedge plate radially disposed between the stator and the rotor and arranged within the first circumferentially arranged groove; a second wedge plate radially disposed between the stator and the rotor and arranged within the second circumferentially arranged groove; a paddle comprising an annular ring having an engagement projection extending outwardly therefrom, the engagement projection having a proximate section and a distal section; the proximate section operatively arranged to engage a central hub, and the distal section operatively arranged to engage either the first or second wedge plates; wherein the paddle and engagement projection are operatively arranged to displace the first or the second wedge plate in either an advance mode or in a retard mode; wherein, in the advance mode, the paddle is displaced in a first circumferential direction to engage the first wedge plate in the first circumferential direction; and, wherein, in the retard mode, the paddle is displaced in a second circumferential direction, opposite the first axial direction, to engage the second wedge plate in the second circumferential direction, opposite the first circumferential direction. 
     Yet another example embodiment comprises a variable camshaft phaser having a rotor arranged to be non-rotatably connected to a camshaft; a spinner, operatively arranged about a central hub, the spinner having a twisting groove therein; a paddle arranged about the spinner comprising an annular ring having an engagement projection extending outwardly therefrom, the engagement projection having a proximate section and a distal section; the proximate section operatively arranged to engage the twisting groove, and the distal section operatively arranged to extend radially outward within a channel. 
     These and other objects, features and advantages of the example embodiments will be readily appreciated by those having ordinary skill in the art upon a reading of the following detailed description of the embodiments in view of the drawings and appended claims. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Various embodiments are disclosed, by way of example only, with reference to the accompanying schematic drawings in which corresponding reference symbols indicate corresponding parts, in which: 
         FIG. 1  is a perspective view of a cylindrical coordinate system demonstrating spatial terminology used in the present application; 
         FIG. 2  is a perspective view of the back face of the camshaft phaser  100 ; 
         FIG. 3  is a perspective view of the front face of the camshaft phaser  100 ; 
         FIG. 4  is an exploded view of the back face of the camshaft phaser  100 ; 
         FIG. 5 a    is a perspective view of the back face of the rotor; 
         FIG. 5 b    is a perspective view of the front face of the rotor; 
         FIG. 6 a    is a perspective view of the paddle; 
         FIG. 6 b    is a perspective view of the spinner; 
         FIG. 6 c    is a perspective view of the central hub; 
         FIG. 7  is a top-down cross-sectional view of the camshaft phaser  100 ; 
         FIG. 8 a    is a side view of the back face of the camshaft phaser  100  in a retard mode; 
         FIG. 8 b    is a side view of the front face of the camshaft phaser  100  in an advance mode where the wedge plate is disengaged; 
         FIG. 8 c    is a side view of the back face of the camshaft phaser  100  in an advance mode where the wedge plate has reengaged; and, 
         FIG. 9  is a perspective view of the front face of the camshaft phaser  100  shown with a cover plate and fastening bolts. 
     
    
    
     DETAILED DESCRIPTION OF EMBODIMENTS 
     At the outset, it should be appreciated that like drawing numbers on different drawing views identify identical, or functionally similar, structural elements. It is to be understood that the invention as claimed is not limited to the disclosed aspects. 
     Furthermore, it is understood that this disclosure is not limited to the particular methodology, materials and modifications described and as such may, of course, vary. It is also understood that the terminology used herein is for the purpose of describing particular aspects only, and is not intended to limit the scope of the claims. 
     Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood to one of ordinary skill in the art to which this disclosure pertains. It should be understood that any methods, devices or materials similar or equivalent to those described herein can be used in the practice or testing of the example embodiments. The assembly of the present disclosure could be driven by hydraulics, electronics, and/or pneumatics. 
     It should be appreciated that the term “substantially” is synonymous with terms such as “nearly”, “very nearly”, “about”, “approximately”, “around”, “bordering on”, “close to”, “essentially”, “in the neighborhood of”, “in the vicinity of”, etc., and such terms may be used interchangeably as appearing in the specification and claims. It should be appreciated that the term “proximate” is synonymous with terms such as “nearby”, “close”, “adjacent”, “neighboring”, “immediate”, “adjoining”, etc., and such terms may be used interchangeably as appearing in the specification and claims. 
     By “non-rotatably connected” elements, we mean that: the elements are connected so that whenever one of the elements rotate, all the elements rotate; and relative rotation between the elements is not possible. Radial and/or axial movement of non-rotatably connected elements with respect to each other is possible, but not required. 
     Adverting now to the figures,  FIG. 1  is a perspective view of cylindrical coordinate system  10  demonstrating spatial terminology used in the present application. The present application is at least partially described within the context of a cylindrical coordinate system. System  10  includes longitudinal axis  11 , used as the reference for the directional and spatial terms that follow. Axial direction AD is parallel to axis  11 . Radial direction RD is orthogonal to axis  11 . Circumferential direction CD is defined by an endpoint of radius R (orthogonal to axis  11 ) rotated about axis  11 . 
     To clarify the spatial terminology, objects  12 ,  13 , and  14  are used. An axial surface, such as surface  15  of object  12 , is formed by a plane co-planar with axis  11 . Axis  11  passes through planar surface  15 ; however any planar surface co-planar with axis  11  is an axial surface. A radial surface, such as surface  16  of object  13 , is formed by a plane orthogonal to axis  11  and co-planar with a radius, for example, radius  17 . Radius  17  passes through planar surface  16 ; however any planar surface co-planar with radius  17  is a radial surface. Surface  18  of object  14  forms a circumferential, or cylindrical, surface. For example, circumference  19  is passes through surface  18 . As a further example, axial movement is parallel to axis  11 , radial movement is orthogonal to axis  11 , and circumferential movement is parallel to circumference  19 . Rotational movement is with respect to axis  11 . The adverbs “axially,” “radially,” and “circumferentially” refer to orientations parallel to axis  11 , radius  17 , and circumference  19 , respectively. For example, an axially disposed surface or edge extends in direction AD, a radially disposed surface or edge extends in direction R, and a circumferentially disposed surface or edge extends in direction CD. 
       FIG. 2  is a perspective view of the back face of the camshaft phaser  100  in a retard mode.  FIG. 3  is a perspective view of the front face of camshaft phaser  100 .  FIG. 4  is an exploded perspective view of the back face of camshaft phaser  100 .  FIG. 5 a    is a perspective view of back face  116  of rotor  114 .  FIG. 5 b    is a perspective view of front face  162  of rotor  114 .  FIG. 6 a    is a perspective view of paddle  146 .  FIG. 6 b    is a perspective view of spinner  134 .  FIG. 6 c    is a perspective view of central hub  132  having first distal  136  end, snap ring  138  washer  140 , and second distal end  142  having a fixed disk  144 .  FIG. 7  is a top-down cross-sectional view of camshaft phaser  100 .  FIG. 8 a    shows a side view of the back face of camshaft phaser  100  in a locked fully retard mode.  FIG. 8 b    shows a side view of the front face of the camshaft phaser  100  in an unlocked neutral mode.  FIG. 8 c    shows a side view of the back face of camshaft phaser  100  in a locked neutral mode.  FIG. 9  is a perspective view of the back face of the camshaft phaser  100  shown with a cover plate and fastening bolts. 
     The following description should be read in view of  FIGS. 2-9 . Camshaft phaser  100  contains a stator  102  having a first radially outwardly facing surface  104  and a first radially inwardly facing surface  106 . The first radially inwardly facing surface  106  has a first plurality of ramps  108 , operatively arranged to receive a first wedge plate  110 . In a preferred embodiment, stator  102  further contains a circumferentially disposed first wedge plate spring  112  arranged between first plurality of ramps  108  and first wedge plate  110 . 
     Camshaft phaser  100  further contains a rotor  114  which is nonrotatably connected to a camshaft C having a back face  116 , a first radially outwardly facing surface  118 , and a first radially inwardly facing surface  120 . First radially outwardly facing surface  118  has a first circumferential groove  122  and a second circumferential groove  124 . First wedge plate  110  is arranged within first circumferentially arrange groove  122  within rotor  114 . Back face  116  of rotor  114  further contains channel  126  and a coaxially arranged groove  128 . Back face  116  has a through bore  130 . Within through bore  130 , there is a central hub  132 , and a spinner  134 . The central hub  132  has a first distal  136  end including a snap ring  138  and a washer  140 , and a second distal end  142  including a fixed disk  144 . Spinner  134  is arranged coaxially about central hub  132 . 
     Camshaft phaser  100  also contains a paddle  146  arranged about spinner  134  and central hub  132 . Paddle  146  has an annular ring  148 , operatively arrange about spinner  134  and within coaxially arranged groove  128 ; and an engagement projection  150  extending radially outwardly therefrom and within channel  126 . In a preferred embodiment, engagement projection  150  is a steel wire that has been bent at a 90 degree angle such that the bent portion can contact first wedge plate  110 . The circumferential width of channel  126  limits the possible circumferential angular motion of engagement projection  150 . 
     Stator  102  further contains a second radially outwardly facing surface  152  and a second radially inwardly facing surface  154 . Second radially inwardly facing surface  154  has a second plurality of ramps  156 , operatively arranged to receive a second wedge plate  158 . In a preferred embodiment, stator  102  further contains a circumferentially disposed second wedge plate spring  160  arranged between second plurality of ramps  156  and second wedge plate  158 . 
     Rotor  114  further contains a front face  162 , wherein said first radially inwardly facing surface  120  further contains an axial groove  164  arranged to receive an anti-rotation projection  166  of spinner  134 . 
     The various figures show the arrangement of stator  102 , with first plurality of ramps  108 , arranged to receive first wedge plate  110 ; rotor  114  having a through bore  130 , a channel  126  and coaxially arranged groove  128  operatively arranged to receive engagement projection  150  and annular ring  148  of paddle  146  respectively. 
     The various figures shows first circumferential groove  122  and second circumferential groove  124  of first radially outwardly facing surface  118  of rotor  114  and the coaxially arranged groove  128  and channel  126  operatively arranged to receive annular ring  148  and engagement projection  150  respectively. 
     The figures also show the axial groove  164  arranged to receive anti-rotation projection  166  of spinner  134 . 
     The figures also show engagement projection  150  and annular ring  148 . In addition, engagement projection  150  further comprises a proximate section  168  and a distal section  170 . Proximate section  168  extends within annular ring  148 . Distal section  170  is shown in a preferred embodiment, bent at a 90 degree angle, such that it can contact, and subsequently disengage, first wedge plate  110 . 
     The figures also show anti-rotation projection  166  and twisting groove  172 . Anti-rotation projection  166  is radially disposed on the outwardly facing surface of spinner  134  and is arranged to slidingly engage with the axial groove  164 . Twisting groove  172  is operatively arranged to receive proximate section  168  of engagement projection  150  that extends within annular ring  148  of paddle  146 . Spinner  134  also contains a through bore  174  arranged to receive central hub  132 . 
     Central hub  132  is arranged within through bore  130  of rotor  114 . During assembly, central hub  132  is placed within through bore  174  of spinner  134 , and spinner  134  and central hub  132  are placed within through bore  130  of rotor  114 . 
     Furthermore, the figures show the positioning of upper spring  176  and lower spring  178 . Upper spring  176  is axially disposed between spinner  134  and central hub  132 . Lower spring  178  is axially disposed between central hub  132  and camshaft C. These springs bias the central hub away from camshaft C. 
     Central hub  132  can be displaced in a first axial direction AD 1 . The central hub can be displaced by a variety of mechanisms known in the art, such as a linear actuator. When central hub  132  is displaced in first axial direction AD 1 , upper spring  176  and lower spring  178  are compressed, and resist the imparted axial motion. Spinner  134 , which is disposed about central hub  132 , is displaced along with central hub  132 . As spinner  134  and central hub  132  are displaced in first axial direction AD 1 , anti-rotation projection  166  of spinner  134  slides along axial groove  164  of first inwardly facing surface  120 . As spinner  134  is displaced in first axial direction AD 1 , the proximate section  168  of engagement projection  150  of paddle  146 , which rides within twisting groove  172 , is forced in first circumferential direction CD 1 . In the absence of linear force in first axial direction AD 1 , upper spring  176  and lower spring  178  force central hub  132  and spinner  134  in a second axial direction AD 2 . Thereby causing proximate section  168  of engagement projection  150  of paddle  146  to ride along twisting groove  172  in the opposite direction axial direction AD 2 , forcing the paddle in a second circumferential direction CD 2 . 
     Paddle  146  can therefore be displaced in first circumferential direction CD 1  or second circumferential direction CD 2 . Distal section  170  of engagement projection  150  of paddle  146  extends through stator  102  allowing for contact with either first wedge plate  110  or second wedge plate  158 . 
     For an advance mode, the central hub  132  and spinner  134  are displaced in first axial direction AD 1 . This motion results in paddle  146  becoming displaced in first circumferential CD 1 . When paddle  146  is displaced in circumferential direction CD 1 , paddle  146  displaces, and subsequently disengages, first wedge plate  110  from first plurality of ramps  108  allowing for rotation of stator  102  free from frictional contact with wedge plate  110 . Stator  102 , which is constantly rotating proportional to the rotation of the engine in first circumferential direction CD 1 , continues to rotation in first circumferential direction CD 1  until it reengages with wedge plate  110  and becomes locked. 
     For a retard mode, the central hub and spinner no longer receive linear force displacing them in first axial direction AD 1 . The absence of linear pressure results in upper spring  176  and lower spring  178  applying pressure in second axial direction AD 2 . This displaces paddle  146  in a second circumferential direction CD 2 . Distal section  170  of engagement projection  150  of paddle  146  displaces, and subsequently disengages, second wedge plate  158  from second plurality of ramps  156  allowing for rotation of stator  102  free from frictional contact with wedge plate  158 . Stator  102 , which is constantly rotating proportional to the rotation of the engine in first circumferential direction CD 1 , continues to rotation in first circumferential direction CD 1  until it reengages with wedge plate  158  and becomes locked. 
     Therefore, depending on whether linear force is applied to central hub  132  in first axial direction AD 1 , first wedge plate  110  or second wedge plate  158  will become disengaged, either advancing or retarding the camshaft timing respectively. It is to be understood that since linear motion imparted on central hub  132  can be precise, it is possible to advance or retard the timing of the camshaft with equal precision. For example, proportional linear motion imparted on the central hub  132  in first axial direction AD 1  could result in an angular rotation as precise as 1 degree in first circumferential direction CD 1 , resulting in an equally precise advancement of overall camshaft timing. 
     It will be appreciated that various of the above-disclosed and other features and functions, or alternatives thereof, may be desirably combined into many other different systems or applications. Various presently unforeseen or unanticipated alternatives, modifications, variations, or improvements therein may be subsequently made by those skilled in the art which are also intended to be encompassed by the following claims.