US 3880127 A
A hydraulic valve gear includes a novel rocker arm and support structure and lubrication means therefor. The rocker arm is mounted for oscillating motion in the plane defined by the axes of the valve stem and hydraulic valve lifter only, which permits the use of a simple, reliable and inexpensive lubrication system for the valve gear.
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United States Patent 1 1 1 1 3,880,127
Abell, Jr. Apr. 29, 1975  HYDRAULIC VALVE GEAR 3.314.404 4/1967 Thompson 123/9035 x 3,359,959 12/1967 Rose 1 1 123/90.42 [751 Invent R01 Abe'L Sugmlm 3.614.943 10/1971 Schlcy 123/9042  Assignee: Eaton Corporation, Cleveland, Ohio 3531-833 11/1971 133/9942 3,661,127 5/1972 Cornell 123/9035 X  Filed: Dec. 7, 1972 3.667.434 6/1972 Sandusky 123/9041 X 21 A LN .;3l3,008 1 1 pp 0 Primary b.\'an1inerManue1 A. Antonakas Assistant E.\'uIn1'nerDaniel J. O'Connor  US. Cl. l23/90.35; 123/9033; 123/9041; Ar Agent, or Firm-Teagno & Toddy 123/9042; 123/9046  Int. Cl. .1 F01! 1/06 57 ABSTRACT  Field of Search 123/9033, 90.35. 90.41,
A hydrauhc valve gear 1ncluc1es a novel rocker arm 1 3/90.42, 90.46
and support structure and 1ubr1cat10n means therefor. [561 CM EffK 23 1 11 bTl1Z iiZ?ifi1l e "$311113 11 in s t v UNITED STA rES PATENTS hydraulic valve lifter only, which permits the use of 11 14431193 1/1933 Page 123/99-35 X simple, reliable and inexpensive lubrication system for 1811959 11/1957 Etchells 123/9035 x the valve gear. 3,289,657 12/1966 Winter, Jr 123/9033 3,313,279 4/1967 Burwcger 123/9042 5 Claims, 3 Drawing Figures HYDRAULIC VALVE GEAR BACKGROUND OF THE INVENTION 1. Field of the Invention This invention relates to valve gear for an internal combustion engine and, more particularly, to valve gear having a novel assembly of hydraulic lifter, rocker arm assembly and mounting which permits the use of a simpler, more reliable and efficient lubrication system for the valve gear of an internal combustion engine.
2. Description of the Prior Art Known prior art internal combustion engine valve gear use a common source, namely the engine oil pump, to provide pressurized oil from the engine oil gallery to supply operating fluid to the hydraulic valve lifter, or tappet, for eliminating valve lash and also to the valve gear for lubrication purposes.
Although such systems have been satisfactory in operation, due to the manner of mounting of the rocker arm in overhead cam engines, an expensive ball and socket fitting between the rocker arm and the valve lifter has been required. An example of such an arrangement is that of US. Pat. No. 3,407,792. The use of such a fitting has also required a complicated means such as cross drilling in the overhead cam engine head to provide the required flow of oil to assure proper rocker arm and valve guide lubrication. Other prior art devices have also included complicated drilling of lubricant passages, hollow locating buttons in slots, and the like. Thus, the prior art structures have been quite complicated and expensive to manufacture. The complexity of the prior art devices has also adversely affected their reliability.
BRIEF SUMMARY OF THE INVENTION The present invention has overcome the problems of the prior art by providing properly lubricated, simply constructed, highly reliable, inexpensive valve gear for an overhead cam engine.
The present invention utilizes a rocker arm which is mounted for oscillation in the plane defined by the valve stem and hydraulic tappet, (lifter), or push rod axes only and requires only a sliding connection between the push rod or lifter, as the case may be. As only a sliding connection is used, a simple hole-to-hole sliding lubricant passageway may be used between the tappet (lifter), or push rod, and the rocker arm which is both reliable and inexpensive to produce.
Accordingly, an object of the present invention is to provide an improved valve gear assembly.
Another object is to provide a new and improved lubrication system for the rocker arm and valve gear.
A further object is to provide a rocker arm which is rotational in the plane defined by the tappet (lifter) and valve stem axes only and thus requires only a sliding contact with the tappet.
Other objects and advantages of the invention will become apparent from the following detailed description taken in connection with the accompanying draw- BRIEF DESCRIPTION OF THE DRAWING FIG. 1 is a partial sectional view showing a portion of an overhead cam internal combustion engine using the valve gear of this invention.
FIG. 2 is a top view of the rocker arm and rocker arm mounting assembly of the present invention.
FIG. 3 is a portion of a section view taken along section-indicating lines 3-3 of FIG. 2.
DETAILED DESCRIPTION OF THE INVENTION The valve gear embodying the present invention may be seen in a preferred form by reference to FIG. 1. In FIG. 1, a portion of an overhead cam internal combustion engine E is illustrated in which 'a tappet which may, if desired, be a hydraulic lifter, translates the motion of a cam 9 through a pivoted rocker arm 30 to movement of an engine poppet valve 20. The poppet valve 20 controls the flow of gases into and from the combustion chamber (not shown) of the engine by cooperation with valve seat 200 and is moved between an upward or closed position and a downward or open position by the rocker arm 30.
The valve gear 21 is actuated by a cam 9 having a base circle 9b which engages the tappet, preferably a hydraulic valve lifter 10. The valve lifter 10 is in turn engaged with one end of the rocker arm 30 which has the remaining end engaged with the stem 23 of poppet valve 20.
Poppet valve 20 is biased by spring 22 into an upward or normally closed position. Upward movements of the hydraulic valve lifter 10 will push upwardly on the left hand end-shoulder 32 of the rocker arm 30, which will pivot about a cylindrical pivot-joint 40, forcing right hand end-shoulder 34 of the rocker arm downwardly onto valve stem 23 which overcomes the bias of spring 22 to move poppet valve 20 downwardly out of contact with valve seat 20a to an open position. As the cam 9 rotates, downward movements of the hydraulic lifter 10 to the base circle 9b of cam 9 result in spring 22 biasing the valve stem 23 upwardly, which closes the valve and forces rocker arm 30 to pivot back about its pivot while maintaining end-shoulder 32 in contact with the lifter 10. As is well known in the art, hydraulic lifter 10 will expand on contact when required, to compensate for changes in length of the valve gear 21 to maintain the proper lash.
It is noted that the invention relates to the engine shown which is of the overhead cam variety, wherein the hydraulic valve lifter 10 directly contacts the rocker arm 30.
The detailed construction of the rocker arm pivot joint 40 may be seen by reference to FIGS. 1 and 2. The rocker arm 30 is formed in a generally upwardly opening cup-like configuration defining a lubricant cavity 36. Centrally located in cavity 36 is an upwardly concave half-cylindrical socket 38 with the cylindrical axis disposed transversely of the arm 30. The socket 38 has a rectangular, transversely extending slot 38a therein. Received in the socket 38 is a half-cylindrical bearing 42 upon which rocker arm 30 pivots. The bearing 42 has a square-section stud 44 extending from the center of the cylindrical surface, which stud 44 is received in a correspondingly shaped recess 53 in the engine E, which recess prevents rotation of the stud 44 and consequently bearing 42 with respect to the engine E. The stud 44 and bearing 42 have a continuous center hole 45 provided therein, through which a mounting bolt 50 is received for securing the stud and bearing 42 to the engine.
Two opposed sides 52 and 54 of the square stud 44 contact two opposed sides of the rectangular slot 38a in the rocker arm and lock the rocker arm against all rotation except in the plane P defined by the axes of the valve lifter and the valve stem by virtue of sides 52, 54 being parallel with said plane P. As is well known to those skilled in the art, a bolt with a square sleeve thereabout may replace integral stud 44. It will also be readily apparent that a stud mounted or fastened to the engine in combination with a square sleeve and nut may be used, if desired.
The valve train is lubricated in a manner which is relatively inexpensive and dependable as will be discussed below. The preferred valve lifter is of the type which uses engine oil to both adjust for valve gear backlash and supply lubricating oil to the valve train; specifically, the lifter is of the constant length metering land type which can be seen in greater detail by reference to U.S. Pat. No. 3,448,730 assigned to the assignee of this invention. It is noted, however, that any type of hydraulic valve lifter which supplies a flow of the valve gear lubricating oil to the top of the lifter, or to the top of the pushrod in a non-overhead cam engine, is equally suited for the present invention.
During engine operation, pressurized lubricant from the engine oil supply is received in the hydraulic lifter inlet 60. A portion of the oil is utilized to operate the lifter 10 for backlash adjustment while a metered portion flows past metering land 61, through cross bore 62, axial bore 64, and out the aperture 66 at the top of the lifter 10.
Since rocker arm 30 is free to rotate or pivot in only a single P plane, a simple sliding contact is maintained between the top of the lifter l and the left hand endshoulder 32 of the rocker arm. The lubricating oil thus flows through lifter aperture 66 directly into rocker arm aperture 32a. The simple hole-sliding-over-hole lubricant connection made possible by the nonrotational mounting of the rocker arm is thus in sharp contrast with the prior art systems.
After the lubricant passes through rocker arm aperture 32a, it is collected in cavity 36 where it lubricates the half-cylindrical bearing 42 and socket 38. From the socket 38, the lubricant will splash and flow downwardly in a manner known in theart as zero pressure lubrication," to lubricate the rocker arm-valve stem sliding connection and valve stem-spring retainer and other portions of the valve gear as shown in FIG. 1.
Although this invention has been described in its preferred form with a certain degree of particularity, it is understood that the present disclosure of the preferred form has been made only by way of example, and that changes in the details of construction and the combination and arrangement of parts may be made without departing from the spirit and the scope of the invention as hereinafter claimed:
1. Valve gear means for use in an internal combustion engine having a driven cam and a source of pressurized liquid lubricant, said valve gear comprising:
a. a valve lifter contacting and following said cam and in fluid communication with said source of pressurized liquid lubricant, said valve lifter providing a metered portion of said lubricant to an aperture in the end thereof remote from said cam, said remote end having a substantially flat surface disposed transversely of the direction of motion of said lifter;
b. a poppet valve for controlling the gas flow to and from the engine combustion chamber, and
c. a rocker arm pivotally interposed between said valve lifter and said poppet valve, said rocker arm having an upwardly opening lubricant-receiving cavity and having a first end portion operatively contacting said remote end of said valve lifter and a second end portion operatively contacting the stem of said poppet valve, such that upon rotation of said cam, axial movements of said lifter result in opposite axial movements of said poppet valve. said first end portion having a convex surface with a lubricant-receiving aperture therethrough, said rocker arm being mounted to said engine for oscillation in the plane defined by the hydraulic valve lifter and poppet valve axes only, said rocker arm convex surface and said substantially flat transverse surface of said hydraulic valve lifter remote end being in sliding communication, with said apertures being in sliding registration for providing a supply of valve gear lubricant to said cavity.
2. The valve gear defined in claim 1, wherein said pivotal mount to said engine includes half-cylindrical bearing means pivotally connecting said rocker arm to said engine for movement only in said plane 3. The valve gear defined in claim 2 wherein said bearing means includes,
a. a half-cylindrical socket formed in said rocker arm intermediate said first and second end-shoulder means; and
b. a bearing having a half-cylindrical bearing surface, said bearing having an integral mounting portion non-rotatably attached to said engine with said bearing surface received in said rocker arm socket.
4. The valve gear defined in claim 3 wherein a. said socket has a rectangular aperture formed therein and b. said mounting portion of said bearing is received through said rectangular aperture.
5. The valve gear defined in claim 1, wherein said lifter is a hydraulic lifter.
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