Patent Publication Number: US-10329967-B2

Title: Phaser oil reservoir on locking cover surface

Description:
FIELD 
     The present disclosure relates to an oil reservoir for a variable camshaft phaser, in particular, a locking cover with a recess for minimizing the total required axial space of the oil reservoir. 
     BACKGROUND 
     A variable camshaft phaser (VCP) is an internal combustion engine component that controls the timing of the valve lift event. The combustion process can be improved when the engine timing is properly varied. The benefits from properly varied engine timing include increased engine efficiency, improved idle stability, torque/potency enhancement, increased fuel economy, and reduced hydrocarbon emissions. Hydraulic VCPs operate utilizing oil pressure (in a closed chamber) and torsionals (kinetic energy) provided by the cams. In general, VCPs comprise a driven element, covers, and a driver element, which is connected to the camshaft in some way. An oil control valve (OCV) is used to control the oil flow supplied by the engine oil pump, via the main oil reservoir, to the VCP inner chambers. When the VCP is full and the proper pressure is established inside, the driver element (i.e., rotor) rotates. This is called camshaft phasing. 
     SUMMARY 
     According to aspects illustrated herein, there is provided an oil reservoir for a variable camshaft phaser, comprising a locking cover, including a front surface including a pool, the pool having a plurality of through-bores, a rear surface including a locking pin channel, a radially inward facing surface, and a radially outward facing surface, and an oil reservoir cover secured to the front surface of the locking cover. 
     According to aspects illustrated herein, there is provided an oil reservoir for a variable camshaft phaser, comprising a locking cover, including a front surface including a pool, the pool having a plurality of through-bores, a rear surface including a locking pin channel, a radially inward facing surface including a recess extending radially outward therefrom, and a radially outward facing surface, and an oil reservoir cover secured to the front surface of the locking cover. 
     According to aspects illustrated herein, there is provided an oil reservoir for a variable camshaft phaser, comprising a locking cover, including a front surface including a pool having a plurality of through-bores, a first plurality of holes operatively arranged to attach the locking cover to the variable camshaft phaser using a plurality of bolts, a rear surface including a locking pin channel, a radially inward facing surface including a recess extending radially outward therefrom, and a radially outward facing surface, and an oil reservoir cover secured to the front surface of the locking cover. 
     It therefore is an object of the disclosure to provide an oil reservoir requiring minimal axial space. 
     These and other objects, features, and advantages of the present disclosure will become readily apparent upon a review of the following detailed description of the disclosure, 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 front perspective view of an oil reservoir; 
         FIG. 3  is an exploded perspective view of the oil reservoir shown in  FIG. 2 ; 
         FIG. 4A  is a front planar view of the locking cover shown in  FIG. 3 ; 
         FIG. 4B  is a rear planar view of the locking cover shown in  FIG. 3 ; 
         FIG. 5  is a cross-sectional view of the oil reservoir shown in  FIG. 2  taken generally along line  5 - 5 ; 
         FIG. 6  is a side view of the oil reservoir shown in  FIG. 2  assembled on a variable camshaft phaser; and, 
         FIG. 7  is a front perspective view of a check valve plate. 
     
    
    
     DETAILED DESCRIPTION 
     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 claims are 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. The term “approximately” is intended to mean values within ten percent of the specified value. 
     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  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 front perspective view of oil reservoir  90 .  FIG. 3  is an exploded perspective view of oil reservoir  90 . Oil reservoir  90  generally comprises camshaft phaser locking cover  20  and oil reservoir cover  80 . Bolts  120  secure oil reservoir cover  80  and locking cover  20  to variable camshaft phaser  100  (shown in  FIG. 6 ). Oil reservoir cover  80  is a circular plate comprising radial surface  82  and frusto-conical surface  86 . For the purposes of this description, oil reservoir cover  80  is arranged concentrically about axis of rotation  24 . Radial surface  82  is an annular ring comprising front surface  82   a , rear surface  82   b , radially inward facing edge  83 , radially outward facing edge  84 , and a plurality of depressions  85 . Radially inward facing edge  83  is circular and comprises radius R 1 . Frusto-conical surface  86  is generally a cone with the narrow end, or tip, removed and comprises proximate edge  86   a  and distal edge  86   b . Proximate edge  86   a  is circular and comprises radius R 2 , equal to radius R 1 . Distal edge  86   b  is circular and comprises radius R 3 , less than radius R 2 . Proximate edge  86   a  is secured to radially inward facing edge  83 . In an example embodiment, oil reservoir cover  80  is formed from thin sheet metal by a suitable manufacturing means, i.e., machined, formed, stamped. It should be appreciated, however, that oil reservoir cover  80  can be formed from any other material suitable to secure to locking cover  20  and create a reservoir for oil capture with minimal axial and radial dimensions. 
     Depressions  85  are sunken areas in front surface  82   a  arranged circumferentially thereon and proximate radially outward facing edge  84 . Cover bolts holes  88  are arranged in each of depressions  85 . Depressions  85  are operatively arranged to align and engage with counter-bores  66 . Cover bolts holes  88  are operatively arranged to align with cover bolts holes  64 . In an example embodiment, as shown in  FIG. 3 , oil reservoir cover  80  comprises depressions  85   a ,  85   b , and  85   c , and cover bolts holes  88   a ,  88   b , and  88   c , arranged about axis of rotation  24  at approximately 100°, 340°, and 220°, respectively. It should be appreciated, however, that any number of cover bolts holes in any arrangement suitable for securing oil reservoir cover  80  and camshaft phaser cover  20  to variable camshaft phaser  100  may be used (see example in  FIG. 6 ). It should also be appreciated, that any suitable means for securing oil reservoir cover  80  and camshaft phaser cover  20  to variable camshaft phaser  100  may be used, e.g., rivets, and that the present disclosure is not limited to using bolts as a securement method. 
       FIGS. 4A and 4B  are front and rear planar views of locking cover  20 , respectively. The following description should be viewed in light of  FIGS. 3, 4A, and 4B . 
     Camshaft phaser locking cover  20  is a circular plate comprising center through-bore  22 , radially outward facing surface  30 , radially inward facing surface  40 , rear surface  50 , and front surface  60 . For the purposes of this description, locking cover  20  is arranged concentrically about axis of rotation  24 . 
     Radially outward facing surface  30  and radially inward facing surface  40  are circumferential surfaces extending axially from front surface  60  to rear surface  50 . Radially inward facing surface  40  comprises recess  42  arranged circumferentially thereon. Recess  42  extends radially outward in direction RIM from radially inward facing surface  40 . Recess  42  is designed to allow oil to drain from variable camshaft phaser  100 , specifically the rotor, so that the locking pin is not prevented from disengaging locking pin channel  52  of cover plate  20 . Oil can drain from the locking pin hole (in the rotor), out of variable camshaft phaser  100  through recess  42 , and into oil reservoir  90 . In an example embodiment, recess  42  comprises surface  44 , surface  46 , and surface  48  (shown in  FIG. 4B ). Surface  44  is a substantially circumferential surface arranged at least partially concentric to radially inward facing surface  40 . In an example embodiment, surface  44  is arcuate and comprises end  44   a  and end  44   b . Surfaces  46  and  48  are substantially axial surfaces. Surface  46  is at least partially planar and extends generally in radial direction RD 1  from radially inward facing surface  40  to end  44   a . Surface  48  is at least partially planar and extends generally in radial direction RD 1  from radially inward facing surface  40  to end  44   b . It should be appreciated, however, that recess  42  may comprise any other design suitable for allowing oil to drain from the rotor locking pin hole of variable camshaft phaser  100 . 
     Rear surface  50  is a substantially planar radial surface directed toward variable camshaft phaser  100  during assembly. Rear surface  50  comprises locking pin channel  52 . Locking pin channel  52  is a groove in rear surface  50  operatively arranged to receive the locking pin of variable camshaft phaser  100 . When locking cover  20  is secured to variable camshaft phaser  100 , locking pin channel  52  aligns with the locking pin hole of the rotor. To stop or limit phasing, the locking pin is forced out of the locking pin hole by the locking pin spring axially toward locking cover  20 . The locking pin engages locking pin channel  52  to non-rotatably connect the rotor with locking cover  20  and the stator (not shown). Rear surface  50  is substantially perpendicular to radially outward facing surface  30  and radially inward facing surface  40 . In an example embodiment, rear surface  50  is not perpendicular to radially outward facing surface  30  and/or radially inward facing surface  40 . 
     Front surface  60  is a radial surface comprising pool  70 , a plurality of oil holes  62 , a plurality of cover bolts holes  64 , and a plurality of counter-bores  66 . Front surface  60  is substantially perpendicular to radially outward facing surface  30  and radially inward facing surface  40 . In an example embodiment, front surface  60  is not perpendicular to radially outward facing surface  30  and/or radially inward facing surface  40 . 
     Pool  70  is a recess formed in the front surface  60  to allow for oil accumulation. Pool  70  comprises bottom surface  72 , outer wall  74 , and island  76 . Bottom surface  72  is generally a radial surface arranged axially between front surface  60  and rear surface  50  (see  FIG. 5 ). In an example embodiment, bottom surface  72  is substantially parallel to front surface  60  and rear surface  50 . Outer wall  74  is generally a circumferential surface arranged proximate to radially outward facing surface  30 . Outer wall  74  is substantially perpendicular to bottom surface  72  and defines an outer radial boundary of pool  70 . Outer wall  74  is the boundary between pool  70  and front surface  60 . In an example embodiment, outer wall  74  is not perpendicular to bottom surface  72 . Island  76  is the area on front surface  60  that corresponds to locking pin channel  52  (i.e., houses/encases locking pin channel  52 ). Island  76  comprises island wall  78 . Island wall  78  is substantially perpendicular to bottom surface  72  and defines a boundary of pool  70 . In an example embodiment, island wall  78  is not perpendicular to bottom surface  72 . 
     Oil holes  62  are through-bores arranged within pool  70  that extend axially from bottom surface  72  to rear surface  50 . Oil holes  62  allow oil to pass, or leak, through locking cover  20  between oil reservoir  90  (formed between locking cover  20  and oil reservoir cover  80 ) and the chambers of variable camshaft phaser  100 , during phasing. This leaking of oil in and out of the chambers, known as oil accumulation, improves the adjustment speed of variable camshaft phaser  100  by accelerating the flow of oil into and out of the chambers. In an example embodiment shown in  FIGS. 4A and 4B , locking cover  20  comprises oil holes  62   a ,  62   b ,  62   c ,  62   d ,  62   e , and  62   f  operatively arranged to align with a corresponding advance or retard chamber when locking cover  20  is secured to variable camshaft phaser  100 . For example, oil holes  62   a  and  62   b  align with the first advance and first retard chambers, respectively, oil holes  62   c  and  62   d  align with the second advance and second retard chambers, respectively, and oil holes  62   e  and  62   f  align with the third advance and third retard chambers, respectively (not shown). It should be appreciated, however, that any number of oil holes suitable for oil accumulation may be used. 
     Cover bolts holes  64  are through-bores arranged around locking cover  20  such that locking cover  20  can be secured to variable camshaft phaser  100 . In an example embodiment, bolts  120  secure locking cover  20  and oil reservoir  80  to variable camshaft phaser  100  by extending through the stator and engaging back plate  110  (shown in  FIG. 6 ). Cover bolts holes  64  extend axially from front surface  60  to rear surface  50 . Counter-bores  66  are arranged in, and at least partially concentric to, each of cover bolts holes  64 . Counter-bores  66  are partial through-bores extending axially from front surface  60  toward rear surface  50  and allow the head of each bolt (or fastener) to be flush with, or below the level of, front surface  60 . It should be appreciated that, in an example embodiment, counter-bores  66  can instead be recessed portions of front surface  60  that are not concentric to cover bolts holes  64 . In an example embodiment, as shown in  FIG. 4A , locking cover  20  comprises cover bolts holes  64   a ,  64   b , and  64   c , and counter-bores  66   a ,  66   b , and  66   c , arranged about axis of rotation  24  at approximately 100°, 340°, and 220°, respectively. In the rear view shown in  FIG. 4B , cover bolts holes  64   a ,  64   b , and  64   c  are shown arranged about axis of rotation  24  at approximately 80°, 200°, and 320°, respectively. It should be appreciated, however, that any number of cover bolts holes in any arrangement suitable for securing camshaft phaser cover  20  to variable camshaft phaser  100  may be used. It should also be appreciated, that any suitable means for securing camshaft phaser cover  20  to variable camshaft phaser  100  may be used, e.g., rivets, and that the present disclosure is not limited to using bolts as a securement method. 
       FIG. 5  is a cross-sectional view of oil reservoir  90  taken generally along line  5 - 5  in  FIG. 2 . Oil reservoir  90  is formed when oil reservoir cover  80  is secured to locking cover  20 . The volume between oil reservoir cover  80  and locking cover  20  defines the volume of oil reservoir  90 . Thus, the volume added to oil reservoir  90  by pool  70  allows the axial distance between oil reservoir cover  80  and front surface  60  of locking cover  20  to be reduced. It is desired that pool  70  have the greatest possible volume to maximize the amount of oil that can accumulate therein. The volume of pool  70  can varied by: changing the depth of pool  70  (i.e., increasing/decreasing the axial distance between front surface  60  and bottom surface  72 ), changing the outer boundary of pool  70  (i.e., increasing/decreasing the radial distance between outer wall  74  and radially outward facing surface  30 ), and changing the areal size of island  76 . 
       FIG. 6  is a side view of oil reservoir  90  shown in  FIG. 2  assembled on variable camshaft phaser  100 . Bolts  120  secure locking cover  20  and oil reservoir  80  to variable camshaft phaser  100  by extending through variable camshaft phaser  100  (specifically the stator) and engaging back plate  110 . Check valve plate  130  is arranged between locking cover  20  and the stator of variable camshaft phaser  100 . Check valve plate  130  regulates the movement of oil through oil holes  62 . 
       FIG. 7  is a front perspective view of check valve plate  130 . Check valve plate  130  is a circular plate comprising front surface  131 , rear surface  132 , radially inward facing edge  133 , and radially outward facing edge  134 . Check valve plate  130  further comprises bolts holes  135 , flaps  136 , gaps  137 , and aperture  138 . Check valve plate  130  is assembled axially between locking cover  20  and the stator of variable camshaft phaser  100  such that front surface  131  abuts against rear surface  50 . Gaps  137  are arranged around flaps  136 . In an example embodiment, check valve plate  130  is assembled axially between locking cover  20  and the stator of variable camshaft phaser  100  such that rear surface  132  abuts against rear surface  50 . Bolts  120  secure oil reservoir  80 , locking cover  20 , and check valve plate  130  to variable camshaft phaser  100  by extending through variable camshaft phaser  100  (specifically the stator) and engaging back plate  110 . Flaps  136  are arranged to align with oil holes  62 . Flaps  136  regulate the movement of oil through oil holes  62 . 
     It will be appreciated that various aspects of the disclosure above 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. 
     LIST OF REFERENCE NUMERALS 
     
         
           10  Cylindrical coordinate system 
           11  Longitudinal axis 
           12  Object 
           13  Object 
           14  Object 
           15  Axial surface 
           16  Radial surface 
           17  Radius 
           18  Surface 
           19  Circumference 
           20  Camshaft phaser locking cover 
           22  Center through-bore 
           24  Axis of Rotation 
           30  Radially outward facing surface 
           40  Radially inward facing surface 
           42  Recess 
           44  Surface 
           44   a  End 
           44   b  End 
           46  Surface 
           48  Surface 
           50  Rear surface 
           52  Locking pin channel 
           60  Front surface 
           62  Oil holes 
           62   a  Oil hole 
           62   b  Oil hole 
           62   c  Oil hole 
           62   d  Oil hole 
           62   e  Oil hole 
           62   f  Oil hole 
           64  Cover bolts holes 
           64   a  Cover bolts hole 
           64   b  Cover bolts hole 
           64   c  Cover bolts hole 
           66  Counter-bores 
           66   a  Counter-bore 
           66   b  Counter-bore 
           66   c  Counter-bore 
           70  Pool 
           72  Bottom surface 
           74  Outer wall 
           76  Island 
           78  Island wall 
           80  Oil reservoir cover 
           82  Radial surface 
           82   a  Front surface 
           82   b  Rear surface 
           83  Radially inward facing edge 
           84  Radially outward facing edge 
           85  Depressions 
           85   a  Depression 
           85   b  Depression 
           85   c  Depression 
           86  Frusto-conical surface 
           86   a  Proximate edge 
           86   b  Distal edge 
           88  Cover bolts holes 
           88   a  Cover bolts hole 
           88   b  Cover bolts hole 
           88   c  Cover bolts hole 
           90  Oil reservoir 
           100  Variable camshaft phaser 
           110  Back plate 
           120  Bolts 
           130  Check valve plate 
           131  Front surface 
           132  Rear surface 
           133  Radially inward facing edge 
           134  Radially outward facing edge 
           135  Bolts holes 
           136  Flaps 
           137  Gaps 
           138  Aperture 
         R 1  Radius 
         R 2  Radius 
         R 3  Radius