The present disclosure relates to barrel or roller lifters for a valve train of an internal combustion engine. In particular, the present disclosure relates to lubrication of rollers and axles for roller lifters.
U.S. Pat. No. 6,880,507 discloses valve lift devices, in particular, roller lifters, for example, the previously known lifter at
Valvetrain components, such as roller lifters, in medium to heavy-duty engines have generally used a roller axle, often comprising a bronze pin supporting plain bearings. This is necessary to carry the heavy loads in a size efficient package. For such designs, lubrication of the roller axle to plain bearing contact area is necessary to reduce friction and wear.
Certain terminology is used in the following description for convenience and descriptive purposes only, and is not intended to be limiting to the scope of the claims. The terminology includes the words specifically noted, derivatives thereof and words of similar import. According to example aspects illustrated herein, a roller lifter is provided, wherein an oil gallery intersects the lifter bore such that oil is available at the outer radial surface of the lifter body. According to example aspects illustrated herein, there is provided a roller lifter including: a hollow cylindrical lifter body including with a push rod contact surface arranged to contact a push rod at an upper axial end of the lifter body, a lower axial wall, two radially opposed struts extending axially from the lower axial wall, an internal cavity, and a hydraulic piston assembly within the cavity; a cylindrical roller having a through bore; a support axle extending at least partially through the strut axle supports and through the roller through bore; an external port located at an outer radial surface of the lifter body, proximate the lower axial wall, the external port extending through the lifter body to an internal port in the lower axial wall; and, at least one depression proximate the opening in the lower axial wall, the depression directed toward at least one strut.
By providing a port at an outer radial surface of the lifter body that would intersect this gallery at or near to full valve lift, parasitic loss of oil is limited and the oil port directs oil to the roller and axle.
The above mentioned and other features and advantages of the embodiments described herein, and the manner of attaining them, will become apparent and be better understood by reference to the following description of at least one example embodiment in conjunction with the accompanying drawings. A brief description of those drawings now follows.
Identically labeled elements appearing in different ones of the figures refer to the same elements but may not be referenced in the description for all figures. The exemplification set out herein illustrates at least one embodiment, in at least one form, and such exemplification is not to be construed as limiting the scope of the claims in any manner.
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.
Prior art roller lifter assembly 100 shown in
Inner cylindrical body 107 contacts pushrod 118 at pushrod end 112 at an upper axial end 111 of body 107, opposite roller 110. Lifter 100 is shown as a lash adjusting element. Oil channel 114 in valve train 102 provides oil supply to an external surface of lifter 100. If switching off of valve 115 is desired, oil is supplied to locking pin 113 in sufficient pressure such that locking pin 113 is displaced against the force of associated compression spring 121 in the radial direction, retracting into body 107. As a result of locking pin 113 retracting, lifter body 105 and inner body 107 are no longer locked in relative position and body 107 can move relative to body 105. During the next cam strokes outer body 105 is shifted relative to inner body 107, with body 107 engaging in lost motion movement against spring 117 located between bodies 105 and 107 in an inner cavity of body 105. Push rod 118 and associated valve 115 are not displaced because the force of compression spring 117 is smaller than the opposing force of valve spring 125.
Depressions 20,21 and guide contour 23 may be varied in depth D, length L and angle of deflection α of contour 23 to direct lubricating oil to different areas of roller 35 and axle 34.
In addition, the desired flow rate of lubricating oil may be achieved by adjusting the diameter of port 5, the depth D of depressions 20,21, the angle α of guide contour walls 23 or radius r in contour 23′″ shown in the embodiment of
In this way, impingement of the oil jet or spray from port 5B on either contour 23 (and the other embodiments of the contour, for example 23′″) or walls 48, 57 of depressions 20,21 causes oil to mainly flow across guide contour surface 58 and wall 49 to depressions 20,21 before dripping down to roller axle 34, roller 35 and roller axle interface surface 36.
In the foregoing description, example embodiments are described. The specification and drawings are accordingly to be regarded in an illustrative rather than in a restrictive sense. It will, however, be evident that various modifications and changes may be made thereto, without departing from the broader spirit and scope of the present invention.
In addition, it should be understood that the figures illustrated in the attachments, which highlight the functionality and advantages of the example embodiments, are presented for example purposes only. The architecture or construction of example embodiments described herein is sufficiently flexible and configurable, such that it may be utilized (and navigated) in ways other than that shown in the accompanying figures.
Although example embodiments have been described herein, many additional modifications and variations would be apparent to those skilled in the art. It is therefore to be understood that this invention may be practiced otherwise than as specifically described. Thus, the present example embodiments should be considered in all respects as illustrative and not restrictive.
Number | Date | Country | |
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61906751 | Nov 2013 | US |