Patent Application
20140283774
The present disclosure relates generally to a method of lubricating a valve train and, more particularly, to a method of lubricating one or more valve train components including dispensing a lubricating fluid through a hole extending radially through a rocker arm insert.
Internal combustion engines, including diesel engines, gasoline engines, gaseous fuel-powered engines, and other engines known in the art, typically include a valve train. The valve train includes intake and exhaust valves in a combustion chamber and a mechanism to cause the valves to open and close. The valve train may include a rocker arm that is pivoted through engagement with a cam positioned on a rotating camshaft to generate the required opening and closing of the intake and exhaust valves. In some instances the valve train may include a hydraulic lash adjuster (HLA) to maintain the desired valve lift and eliminate the need for periodic adjustment of the valves. A lubricating mechanism may also be provided in the valve train to lubricate valve train components during operation.
U.S. Patent Application Publication No. 2003/0037744 to Yates (the '744 publication) discloses a method of retaining a rocker lever ball socket on a rocker lever ball of a rocker lever. The rocker lever ball includes a first fluid channel in fluid communication with an engine and the rocker lever ball socket includes a second fluid channel. The first and second fluid channels align at a predetermined rotation of a rocker lever shaft to complete a fluid path to the exterior of the rocker lever ball socket. However, the lubrication method contemplated by the '744 publication is not ideal in all valve trains and can result in insufficient or excessive lubrication under certain conditions.
The method and apparatus of the present disclosure alleviates one or more deficiencies of the prior art.
Another aspect of the present disclosure relates to a rocker arm insert assembly comprising: a rocker arm including a first fluid passage therein; and an insert including a first end carried by the rocker arm, a second end opposite the first end, and a second fluid passage, wherein the second fluid passage in the insert is in fluid communication with the first fluid passage in the rocker arm and the second fluid passage includes a discharge portion extending radially to an outer surface of the insert.
One aspect of the present disclosure relates to a method of lubricating one or more valve train components comprising the steps of supplying a lubricating fluid to a fluid passage in an insert in a rocker arm, the insert having a first end carried by the rocker arm and a second end movably secured to a fluid collecting member; and dispensing the lubricating fluid onto the fluid connecting member through a radially extending discharge portion of the fluid passage in the insert.
One aspect of the present disclosure relates to a rocker arm assembly comprising a rocker arm including a first fluid passage therein; and an insert having a first end carried by the rocker arm, a second end opposite the first end and adapted to be movably connected to a fluid collecting member, and a second fluid passage in the insert, wherein the second fluid passage in the insert is in fluid communication with the first fluid passage in the rocker arm and the second fluid passage includes an axial portion extending longitudinally along the insert and a discharge portion extending radially to an outer surface of the insert, the discharge portion being positioned to deliver lubricating fluid to the fluid collecting member.
Referring now to
Valve train 100 includes one or more rocker arms 102 mounted on and capable of pivoting about a rocker arm shaft 104 (
Referring to
In operation of the engine the roller assembly 109 rides on the outer surface of the cam 110 to generate a reciprocating motion of the connecting rod 112, causing pivoting of the rocker arms 102 about the rocker arm shaft 104. The number and spacing of the rocker arms 102 and cams 110, and the related components, may vary depending upon the particular size and design of the engine, and in particular depending upon the number of intake and exhaust valves 106 and 108.
Referring now to
As best seen in
A first bore 136 may be provided in the first enlarged end portion 133 of the first arm 132. The first bore 136 may be generally cylindrical in shape and may be positioned substantially concentrically within the first enlarged end portion 133. Thus, the first bore 136 may have a center axis that is oriented generally perpendicular to the axis of rotation of the rocker arm shaft 104. In an exemplary embodiment, the first bore 136 may be a blind bore extending less than entirely through the first enlarged end portion 133 of first arm 132. However, it is also contemplated that a through bore may be provided that extends though the entirety of the first enlarged end portion 133.
Similarly, a second bore 138 may be provided in the second enlarged end portion 135 of the second arm 134. The second bore 138 may be generally cylindrical in shape and may be positioned substantially concentrically within the second enlarged end portion 135. Thus, the second bore 138 may have a center axis that is oriented generally perpendicular to the axis of rotation of the rocker arm shaft 104. In the embodiment depicted, the second bore 138 is a through bore that extends through the entirety of the second arm 134. However, similar to first bore 136, the second bore 138 may alternatively be provided as a blind bore.
A first rocker arm insert 140 may be carried by and extend from the first enlarged end portion 133. At least a portion of the first rocker arm insert 140 may be received in the first bore 136 and secured therein to resist removal. Similarly, a second rocker arm insert 142 may be carried by and extend from the second enlarged end portion 135. At least a portion of the second rocker arm insert 142 may be received in the second bore 138 and secured therein to resist removal. The first and second rocker arm inserts 140, 142 may be secured in the first and second bores 136, 138, respectively, by any method or mechanism known to those skilled in the art, including, but not limited to, a press fit, a threaded attachment, or other mechanical retention system.
The first rocker arm insert 140 may include body member 144 having a first end 146 and a second end 148 located on opposing longitudinal ends of the body member 144. The axial distance between the first end 146 and second end 148 defines a longitudinal length L of the first rocker arm insert 140. At least a portion of the body member 144 adjacent to the first end 146 may have a shape, as defined by an outer surface 150, that is adapted to be received in the first bore 136 in the first arm 132 of the rocker arm body 124.
The second end 148 of the first rocker arm insert 140 may be movably connected to a fluid collecting member 152 to allow the first rocker arm insert 140 to pivot relative to the fluid collecting member 152. In an exemplary embodiment, the second end 148 of the first rocker arm insert 140 may include a spherical cap 154, and the fluid collecting member 152 may include an inner cavity 156 having a generally spherical well portion 157. The spherical cap 154 may be formed by a generally spherical end portion having a shoulder 158 defined by an intersecting plane on an upper side of the spherical end portion. The spherical cap 154 and the generally spherical well portion 157 together form a ball-and-socket type joint that allows a degree of rotational movement between the fluid collecting member 152 and the first rocker arm insert 140. While a particular movable connection has been described herein and shown in the drawings, it is also contemplated that other known movable connecting mechanisms may be used to movably secure the first rocker arm insert 140 to the fluid collecting member 152.
The fluid collecting member 152 may further include an annular depression 160 at a top edge of the generally spherical well portion 157, the annular depression 160 having an increased diameter D4 as compared to the diameter D3 of the generally spherical well portion 157 and providing an increased volume of the inner cavity 156 formed within the fluid collecting member 152 (see
The spherical cap 154 of the insert may have a diameter D1 larger than the diameter D2 of the body member 144 and approximately equal to the diameter D3 of the generally spherical well portion 157 in the fluid collecting member 152. Thus, the dimensional relationship of the components may be described as follows:
D
2<(D1, D3, D5)<D4
where D1 is the diameter of the spherical cap 154, D2 is the diameter of the body member 144, D3 is the diameter of the generally spherical well portion 157, D4 is the diameter of the annular depression 160 and D5 is the diameter of the upper opening 162.
The diameter D1 of the spherical cap 154, and therefore the approximate diameters D3 and D5 of the generally spherical well portion 157 and the upper opening 162 respectively, may be between approximately 7 and 22 mm, in other embodiments between approximately 10 and 20 mm, and in yet other embodiments between approximately 12 and 17. In an exemplary embodiment, the diameter D2 of the body member 144 may be between approximately 4 and 10 mm and the diameter D5 of the upper opening may be between 7 and 22 mm.
The inner cavity 156 of the fluid collecting member 152 may have a height H1 measured from the bottom of the spherical well portion 157 to a top surface 153 of the fluid collecting member 152 adjacent to the upper opening 162 that is between approximately 4 and 12 mm, and in an exemplary embodiment is approximately 10 mm.
In particular embodiments, the fluid collecting member 152 may be provided in the form of a rocker arm button positioned on a top surface of a bridge 163 (
Referring back to the first rocker arm insert 140, as best shown in
An insert fluid passage 176 can extend through at least a portion of the first rocker arm insert 140 and may have an opening in the outer surface 177 of the spherical cap 154. The insert fluid passage 176 may include an axial portion 178 extending longitudinally along the first rocker arm insert 140 at least partially between the first end 146 and second end 148. In a particular embodiment the axial portion 178 of the insert fluid passage 176 may be a blind bore extending from the outer surface 177 of the spherical cap 154 to an end point 179 adjacent to the first end 146. A radial inlet passage 180 may extend through the first rocker arm insert 140 between the axial portion 178 of the insert fluid passage 176 and the circumferential recess 164 to facilitate fluid communication between the rocker arm fluid passage 166 and the insert fluid passage 176.
The insert fluid passage 176 may also include a discharge portion 182 extending radially from the axial portion 178 to the outer surface 150 of the first rocker arm insert 140. The discharge portion 182 may be located in the body member 144 of the first rocker arm insert 140 adjacent to the spherical cap 154. The discharge portion 182 may define an exit orifice 184 in the outer surface 150 of the body member 144. The exit orifice 184 may be positioned adjacent to the shoulder 158 of the spherical cap 154. In an exemplary embodiment the discharge portion 182 may extend at an approximate right angle relative to the axial portion 178 of the insert fluid passage. However, it is contemplated that the discharge portion 182 may be alternatively oriented relative to the axial portion 178 while extending radially toward the outer surface 150, such as, for example, by extending at an approximately 45 degree angle relative to the axial portion 178.
In certain embodiments, the discharge portion 182 of the first rocker arm insert 140 may have a diameter of less than approximately 1.75 mm (0.07 inch), in other embodiments a diameter of less than approximately 1.70 mm (0.07 inch), and in yet other embodiments a diameter of less than approximately 1.65. In the same or other embodiments, the discharge portion 182 of the first rocker arm insert 140 may have a diameter of between approximately 1.40 and 1.80 mm (0.06 and 0.07 inch), in other embodiments between 1.45 and 1.75 mm (0.06 and 0.07 inch), and in yet other embodiments between 1.50 and 1.70 mm (0.06 and 0.07 inch). In a particular embodiment, the discharge portion 182 may have a diameter of approximately 1.60 mm (0.06 inch). In an exemplary embodiment the axial portion 178 of the insert fluid passage 176 may have a diameter equal to the diameter of the discharge portion 182 to allow for manufacturing efficiency.
The exit orifice 184 of the discharge portion 182 may be longitudinally spaced from a distal end 185 of the spherical cap 154 by a distance H2 of between approximately 4 and 10 mm. The distance H2 that the exit orifice 184 is spaced from the distal end 185 may be less than the height H1 of the inner cavity 156 to ensure that the exit orifice 184 is positioned within the inner cavity 156 when the first rocker arm insert 140 is movably secured to the fluid collecting member 152.
The second rocker arm insert 142 may be similar in many respects to the first rocker arm insert 140, and in certain embodiments may be substantially identical absent the spherical cap 154 feature. However, it is also contemplated that the second rocker arm insert 142 may include distinctions from the first rocker arm insert 140. In an exemplary embodiment the second rocker arm insert 142 may be secured in the second bore 138 by a nut 186 threaded over a threaded top portion 188 of the second rocker arm insert 142.
The second rocker arm insert 142 may be operatively engaged with the connecting rod 112. In a particular embodiment, the bottom surface 190 of the second rocker arm insert 142 may engage the plunger 116 of the HLA 113 (
The disclosed method of lubricating one or more valve train components, and the disclosed rocker arm assembly and rocker arm insert, may be useful in any internal combustion engine including diesel engines, gasoline engines, gaseous fuel-powered engines, and other engines known in the art. More particularly, the disclosed method and apparatus may be useful in an internal combustion engine that includes an HLA within the valve train. The HLA may render known valve train lubrication methods and mechanisms ineffective due, at least in part, to reduced clearances between components of the valve train.
The method of the present disclosure contemplates lubricating one or more components of the valve train by dispensing lubricating fluid from a radial discharge portion 182 of a fluid passage 176 in a rocker arm insert. The lubricating oil is provided to the rocker arm bearing 128 by a hole in the rocker arm shaft 104. The oil then travels through the rocker arm fluid passage 166 in the first arm 132 of the rocker arm body 124. The lubricating fluid then flows from the rocker arm fluid passage into the insert fluid passage 176 and exits from the insert through a radial discharge portion 182 and exit orifice 184. The lubricating fluid may then be captured by the inner cavity 156 in the fluid collecting member 152, thereby minimizing the amount of oil mist generated, which in turn may minimize the oil load on a crankcase ventilator mounted adjacent to the rocker arm assembly.
It will be apparent to those skilled in the art that various modifications and variations can be made to the method of lubricating a valve train and rocker arm insert of the present disclosure without departing from the scope of the disclosure. Other embodiments will be apparent to those skilled in the art from consideration of the specification and practice of the method and device disclosed herein. It is intended that the specification and examples be considered as exemplary only, with a true scope of the disclosure being indicated by the following claims and their equivalent.
