US2713855A

US2713855A - Inter-nested rocker arrangement for overhead valve gear

Info

Publication number: US2713855A
Application number: US389665A
Authority: US
Inventors: Julius E Witzky
Original assignee: Studebaker Packard Corp
Current assignee: Studebaker Packard Corp
Priority date: 1953-11-02
Filing date: 1953-11-02
Publication date: 1955-07-26
Anticipated expiration: 1972-07-26

Description

July 26, 1955 J, w Tz 2,713,855

INTER-NESTED ROCKER ARRANGEMENT FOR OVERHEAD VALVE GEAR Filed Nov. 2, 1953 3 Sheets-Sheet 1 FIG. fil

[-7 Z INVENTOR.

JULIUS E. WITZKY July 26, 1955 J. E. WITZKY 2,713,355

INTER-NESTED ROCKER ARRANGEMENT F OR OVERHEAD VALVE GEAR Filed Nov. 2, 1953 3 Sheets-Sheet 2 INVENTOR. JUL/us E M/ITZKV July 26, 1955 J, wn- K 2,713,855

INTER-NESTED ROCKER ARRANGEMENT FOR OVERHEAD VALVE GEAR Filed Nov. 2, 1953 5 Sheets-Sheet 3 INVENTOR. JUL/us E. M/ITZ/(Y W MLJIW M ATTORNEYS.

United States Patent INTER-NESTED RUCKER ARRANGEMENT FOR OVERHEAD VALVE GEAR Julius E. Witzky, Royal Oak, Mich assignor to Studebaker-Packard Corporation, a corporation of Michigan Application November 2, 1953, Serial No. 389,665 1 Claim. (Cl. 123-90) The present application relates to paired rocker arms for operating overhead valves in internal combustion type engines, and particularly relates to an inter-nested rocker arrangement for overhead valve gear incorporating one or more groups of simultaneously actuatable valves.

Engines having rocker-arm-operated dual inlet and exhaust valves are well known in the art as illustrated by the U. S. Patent 1,284,250 and the advantages inherent in an arrangement of dual sets of overhead valves disposed in symmetry with respect to the central axis of an engine cylinder head are generally recognized. A continuing problem has confronted the designer of the rocker arm members for such valves however and the somewhat compromise solution as to location of these members has generally followed one of two approaches. First, the rocker arm members as selected are of a number greater than half the number of the collective valves controlled thereby and are separately operated, in which case the rocker arm members require a relatively greater number of actuator push rods than required in other simultaneously operable valve arrangements. Second and alternatively, the rocker arm members may beof the same number as the sets of dual valves controlled thereby, in which case the dual valves of each set are arranged to be operated directly, not by the arm member itself, but by an intermediate cross head or equalizing beam member which causes the dual valves proportionally to divide and share the reaction of the arm member thrust so as to be generally coordinated in their movement. In any case though, the more usual approach hitherto to the solution of the problem has constantly been attended with the disadvantages of too many separate parts either from standpoint of number of push rods and/or parts separately secured to the supporting head structure, or else parts separating the rocker member from its two or more controlled valves.

An object of the present invention is to overcome or minimize the foregoing disadvantages and in so doing to provide an inter-nested rocker arrangement for operating simultaneously actuatable intake and exhaust valves in an engine cylinder head. According to a feature of the invention a group of intake valves is operated by a single unitary rocker member and a second group of exhaust valves symmetrically disposed with respect to the first group is operated by another single unitary rocker member, the arrangement being such that one rocker member both straddles and supports the other member for independent relative rotation.

Another object is to provide a concentric pair of valve actuated rocker members disposed one. within the other with the outer member having a centrally open hub and the inner member extending therethrough with the function of a supporting axle for the hub.

A further object is to provide, in a cylinder head having a ring of valves disposed about a central cyclically timed and operated depending combustion controlling device for an axially aligned cylinder, a pair of unitary dual rocker arm structures operated from a pair of push rods disposed substantially in a single plane parallel to the axis of the Patented July 26, 1955 cylinder and operating the rocker arm structures such that they oscillate about a common horizontal axis intermediate the plane of the push rods and the axis of the cylinder. According to a feature of the invention the common horizontal axis of the rocker arm structures is determined by the novel fact that one of the rocker structures is journalled at its opposite ends in a pair of stationary end bearings for oscillation about said axis and the one rocker structure has a concentric midportion journalling a support bearing for the other of the rocker structures which is thereby independently oscillatable with respect thereto about such axis. In addition to being journalled by the self-journalling one rocker structure, the other rocker structure has a pair of valve operating arm members which diverge from a common base on such structure to straddle the above referred to depending combustion device and which in turn are straddled at their base by a pair of valve operating arm members mounted to the one structure.

Another object of the invention is the provision, in a cylinder head, of a concentric pair of inter-nested dual rocker structures which may be mounted by a simple twopiece mounting bracket detachably secured to the head and which accordingly may be readily dismantled for service or inspection into their individual components.

Another object is to provide an uncomplicated dual rocker arrangement for simultaneously actuatable intake valves and exhaust valves, which is simplified to the extent of lending itself to readily achieved economies of manufacture and to ease of assembly in the conveyor line process of fabrication in manufacture.

Further features, objects and advantages will either be specifically pointed out or become apparent when for a better understanding of the invention reference is made to the following written description taken in conjunction with the accompanying drawings in which Fig. l is a side elevational view of an engine incorporating the present valve rocker invention;

Fig. 2 is a continuous plan view taken along the successive engine levels indicated at 22 in Fig. 1;

Fig. 3 is a transverse section of the engine taken along the lines 3-3 of Fig. 2 and Fig. 4 is an exploded view in perspective of the ultimately inter-nested valve rockers for the engine.

In Figs. 1 through 4 of the drawings an engine source The engine includes one or more Fig. l, and these cylinders are provided with a common exhaust manifold 12 for leading waste gases to the rear of the engine and the cylinders are further provided with an induction manifold 14 for superatmospheric air which leads forwardly to the cylinders. A forced stream of super-atmospheric air is supplied to the intake manifold 14 by an impeller component I and the hot waste gases from the exhaust manifold 12 may be utilized as the motive fluid supply for energizing a gas turbine component Ghaving an exhaust discharge pipe 16 leading to an engine muffler, not shown. The provision of the gas turbine is optional but when so provided as in accordance with the present preferred embodiment of the invention,

V the turbine component G operates in conjunction with the impeller component I to form a so-called turbocharger unit which by being compounded with the prime engine source P utilizes the othewise wasted hot exhaust gases to provide an auxiliary source of power. A split path slip drive transmission T having both mechanical and hydrodynamic components is provided for coupling the engine P to a load indicated by a propeller shaft 18 in conjunction with a change speed constant mesh gear unit U. For a more complete description of the transmission T, reference may be had to the copending application Serial No. 355,086 filed May 14,

1953, in the name of the present inventor Julius E. Witzky jointly with the co-inventor thereof Carroll J. Lucia.

The gear or transmission unit U is internally valve operated through a control valve, not shown, which is under the control of a lever 20 pivoted at 22 to the side of the case of the gear unit U. A manually shiftable control link 24 is pivotally attached to the outer end of the control lever 20 to afford operator control over the gear unit U. In one upper corner of the transmission T a forwardly extending accessory drive shaft 26 is provided which is drivingly connected to a lubricating oil pump indicated at 23 at the forward end of the engine P. The accessory drive shaft 26 also drivingly carries a sheave at the forward extremity thereof which by means of a V-belt 30 is drivingly connected to a sheave fixed to a shaft 32 for driving an engine cooling fan 34. The shaft 32 carries another sheave which by means of a V-belt 36 drives a rotor-carrying shaft 38 for a generator 40. The shaft 32 additionally drives a water pump indicated at 41. In the present diesel type engine P a bank of fuel injection pumps 44 is provided in number corresponding to the number of cylinders 10 and the fuel injection pumps 44 along with a cam shaft 45 are connected by a subsequently described chain drive 47 so as to be driven at one-half the crankshaft speed of the engine P. The air impeller I supplying the induction manifold 14 has a flanged inlet 46 to which there is fastened a combined air filter and silencer 48. The air filter 48 carries a cover detachably connected thereto as by a wing nut 50.

The previously referred to crankshaft of the engine P includes a crankshaft throw portion 52 and is mounted in bearings in the engine P for rotation about a principal longitudinal axis 54' in alignment with the load shaft 18. The crankshaft indicated at 52 has a gear 56 concentric therewith and fast thereto which is connected by the silent type chain 47 to a similar gear '8 of twice the number of teeth as the gear 56. The gear 58 is splined to the cam shaft 45, and also splined to the camshaft 45 there is provided another gear 60 enmeshed with a companion gear 62 which is of the same number of teeth as the gear 60 and which commonly drives the individual pumps in the injector pump bank 44. The resulting drive between the crankshaft gear 56 and the camshaft 45 and injector pump gear 62 is in the ratio of a 1:2 reduction which results in the previously described relationship whereby the camshaft and the injector pumps operate at one-half crankshaft speed. The previously noted throw portion of the crankshaft 52 is journalled in a bearing 64 non-rotatably clamped by a two-piece piston rod structure 66 which is bolted together as by two cap bolts at 68. The piston rod 66 has an upper end carrying a wrist pin 70 connecting the same to a reciprocable piston 72 which is slidable within a combustion or working chamber 74 at the head end of a wet type cylinder liner 76. The liner 76 is sealingly received in a cylinder chamber 78 which is formed in the case 80 of the engine block and which provides a surrounding water space for cooling the cylinder liner. The piston reciprocates in the liner in a vertical path along a central axis 82 common to the cylinder. The corresponding axes 82 for the cylinders occupy a plane commonly termed the plane of the cylinders and indicated at 33 in Fig. 2. Generally parallel to the plane of the cylinders, there is provided row of push rods, two to a cylinder and one comprising an intake valve push rod 84 and the other comprising an exhaust valve push rod 86. At the right hand side of the casing 80 for the engine P as seen in Figure 3, an inspection plate 88 is suitably mounted and sealed thereto as by a gasket '90 to form a detachable cover for a hand holc opening 92 providing for access to the side of the engine adjacent the plane of the row of vertically lifted

push rods

84, 86, such plane appearing at 85 in Fig. 2. Each push rod seats at its lower end in a ball and socket joint 94 formed in a hydraulic valve lifter 96 of conventional type. The hydraulic valve lifters 96 operate in known manner to provide automatic valve clear ance adjustment with zero lash and the group of lifters 96 which engage the exhaust push rods such as at 86 is operated by a set of lobed exhaust valve cams 100 whereas the group of lifters 96 for the intake push rods 84 is operated by a set of lobed intake cams 102 fast to the camshaft 45.

A cylinder head gasket 104 is clamped between an internally passaged and ported cylinder head 106 and the face of the cylinder block adjacent the top end of the cylinder case 80. The cylinder head 106 includes a pair of ported intake passages 108 connected to the intake or induction manifold 14 and further includes a pair of exhaust passages 110 which are connected to the exhaust manifold 12. Suitable internal cavities as at 112 for cooling water are provided in the head 106. Each pump of the injector bank 44 is connected as by a pipe 114 to a fuel injector nozzle 116 which is centrally carried by the head 106 and which depends through an opening into the cylinder as at 119 along the central axis 62 so as to control the firing and combustion process from a central position in the working chamber 74'. About the depending injector 116 as a center, there are provided groups of simultaneously actuatable inlet and

exhaust valves

118, 120, which conform to a circular path of revolution so as to form a general valve ring at 122. The thin-shanked inlet valves 118 are paired and control the valve ports of the correspondingly paired inlet passages 108 and the thick-shanked exhaust valves 120 are similarly paired and control the valve ports of the corresponding pair of exhaust passages 110. A bleed back line 124 is connected to each of the injector nozzles 116 so as to provide a controlled by-pass flow of fuel oil from the injector nozzles which among other functions aids in conducting heat away from the same.

The intake valves 118 for each cylinder, having a pair of concentric return springs 127, are arranged to be actuated by a pair of short arm members 126 which are longitudinally spaced apart and on the same side with respect to a generally horizontally extending reference axis 128 disposed between the plane of the cylinders at 83 and the plane of the push rods at 85. One of the two arm members 126 for each cylinder 76 is integral with a rocker shaft structure 129 and the other armmember 126 is internally splined as at 130 and received on a companion set of splines 132 formed on a portion of the rocker structure 129. On the opposite side of the reference axis 128, the rocker structure 129 has an integral actuating arm portion 134 which is transversely aligned with respect to the integral arm member 126 and which forms a ball and socket joint as at 136 with the upper end of the intake valve push rod 84. The rocker structure 129 is of a generally elongated hollow construction concentric to the reference axis 128 and is journalled at its opposite ends 138 in a pair of spaced apart sleeve bearings 140 carried by a two-piece support bracket structure 1.42. Each piece or bracket of the support structure 142 is secured as by two or more bolts 144 to the cylinder head 106. A detachably bolted-on cover 146 may be provided for each cylinder head 106 so as to enclose fully its valve chamber as at 147. The closed valve chamber 147 overlies the combustion chamber 74 in a vertically spaced arrangement with the head structure 106 intervening. The

valves

118 and 120 in the head structure and the chamber 74 are symmetrically disposed about the longitudinal axis 82 of the cylinder 76. The short arm rocker shaft structure 129 for each cylinder has a smooth midportion 152 forming a journal for receiving a rocker-supporting sleeve bearing 150. The bearing supports a hubbed rocker arm structure 148, the mean plane 149 of which contains the longitudinal axis 82 of its corresponding cylinder 76 and forms the mid-- plane as between the end bearings 140 and also as between the pairs of the exhaust valves 120 and the intake valves 118, all valves of which are therefore equidistant therefrom. The plane 149 defines the plane of oscillation of the rocker structure 148 about the reference axis 128, and is in a vertical disposition normal to the latter, and normal to the parallel planes of the cylinders and the push rods at 83 and 85 respectively. The rocker structure 148 integrally carries a diagonally laterally protruding actuating ann 154 forming a ball and socket joint as at 156 with the upper end of the exhaust push rod 86. In addition, the rocker structure 148 carries a long pair of valve operating arms 158 which are longitudinally spaced apart with respect to the common axis 128 and which diverge from a common point or juncture 160 with the rocker structure 148. The valve operating arm members 158 diverge so as to straddle the central depending injector nozzle 116 without any interference therewith. The thick-shanked exhaust valves 120 are operated by the long operating arm members 158 and for the purpose of their return stroke are provided with a pair of concentric return springs 161. l

The extreme parts of each long arm 158 and the shank of the associated exhaust valve 120 may be provided with an interposed manually adjustable screw or tappet carried by the one part and engaging the other part so as to provide for valve clearance adjustment in known manner, but as shown, these parts directly engage one another with a rolling-sliding frictional contact and any and all compensation or adjustment in the valve train is automatically accomplished by means of the hydraulic tappets 96. Similarly, all compensation or adjustment in the valve train which includes each short arm 126 and its associated thin shanked intake valve is automatically accomplished by means of the corresponding hydraulic tappet 96 in the train and nointerposed manually adjustable screw or tappet is necessary at the end of the short arm 126. The actuating arm member 154 for the rocker structure 148 is transversely aligned with respect to one of the two short valve operating arms 126 but is on the opposite side of the axis of oscillation 128 and similarly as noted, the push rod actuated arm member 134 for the rocker structure 129 is transversely aligned with respect to the other one of the short valve operating arm members 126 but on an opposite side of the oscillation axis 128 with respect thereto.

The assembly of the inter-nested rocker combination, best understood from the exploded view of Fig. 4, is efiected in that first the interposed sleeve bearing 150 is slid over the smooth midportion 152 of the elongated shaft structure 129 so as to be clear of the inner end of the splines 132. The long armed rocker structure 148 is moved into place with its hub over the sleeve bearing 150 such that its mean plane 149 coincides with the transverse central plane of the midportion of the elongated rocker shaft structure 129. Then the rocker member 126 having the internal splines 130 is slid along the splines 132 to its non-rotatable position adjacent the rocker member 148. Thereupon the end bearings 140 are moved over the opposite ends 138 of the shaft member 129 and are thus ready to be made secure in the two piece support bracket 142 which is bolted as at 144 to the valve chamber base in the head 106.

In the operation of the engine herein described, the crankshaft 52 drives the camshaft 45 at one-half crankshaft speed due to the 1:2 reduction afforded by the chain drive 47 and its associated gearing. Let the direction of rotation of the crankshaft 52 be assumed as being clockwise in Fig. 3. The camshaft 45 likewise assumes the clockwise direction indicated by an arrow 162 in Fig. 3 and the exhaust cam 100 rotates under the corresponding lifter 96 to lift the push rod 86 and cause the longarmed dual rocker 148 to open the pair of exhaust valves 120 and then allow them to start to close. Thereupon the intake cam 102 will act and lift the corresponding lifter and push rod 84 to cause the rocker 129 and the short arms 126 thereof to move and effect a predetermined amount of initial movement of the pair of intake valves 118 prior to full closing of the exhaust valves, depending of course on the desired amount of valve overlap for the particular engine. The intake and exhaust valves 118 and are disposed according to and reciprocate along axes each of which is parallel to the midplane 149 and parallel to the central axis 82' of the cylinder 76. The intake valves 118, however, are relatively near the rocker axis 128 whereas the exhaust valves 120 are shown tobe more remote with respect thereto. The entire valve operation and also the injection is coordinated in timed relationship to the operation of the piston 72 and the crankshaft 52, and the exhaust valves 120 in each cylinder begin to open at or about the time at which the piston 72 begins the upward or so called exhaust stroke which immediately follows the downward or combustion stroke of the piston. The

dual rocker structures

129, 148 in conformity with the above operation have a timed sequence whereby the relatively long rocker members 158 are first rocked counterclockwise according to an arrow 164 in Fig. 3 and toward the end of their clockwise return stroke the other or short rocker members 126 begin their counterclockwise direction of oscillation to accomplish the required degree of valve overlap. At the time that the long rocker 148 is fully restored to its unactuated position the short rocker arms 126 are in an initial position of advanced opening movement and thereafter complete the opening and closing movements while the long rocker arms 158 remain in their unactuated or restored position.

As herein disclosed, both the rocker-actuatable intake and the exhaust valves are arranged in sets of pairs forming a ring about a central depending combustion controlling injector device. It is evident that the actuating rockers are easily adaptable to operate valves in sets of threes or more, which sets may or may not necessarily conform to a circular path of revolution in the strict sense of the term ring and which may be associated with different forms of depending combustion controlling devices as for instance a spark plug, an injector, or both. So also the drawing shows one of the two arms on the short armed rocker member 129 to be detachably splined thereto and the other arm to be integral therewith, but self-evidently the arms may both be splined to the member 129 and either one or both the arms may be secured thereto as by keying or otherwise made fast thereto. The thickemmed pair of exhaust valves 120 are shown to be relatively remote to the axis of oscillation 128 for the dual rockers but indeed it is not essential that they be farther away from this axis than the intake valve 118 and to the contrary the exhaust valves may be relatively adjacent and the intake valves relatively remote as to their location with respect to the rocketr axis 128.

Variations within the spirit and scope of the invention described are equally comprehended by the foregoing description.

I claim:

A rocker assembly for attachment to a cylinder head comprising an elongated hollow rocker structure having an externally smooth mid-portion, similarly smooth opposite end portions, and a splined section between the mid-portion of the rocker structure and one of said end portions, spaced apart support bracket means detachably secured to the cylinder head and recessed to receive the opposite end portions of the rocker structure therein, another rocker structure having a hub surrounding the mid-portion of said hollow rocker structure, a sleeve bearing element in each recess of the bracket means and cooperating with the other sleeve bearing element for journably centering the opposite end portions of the hollow rocker structure for anti-friction rocking movement about a fixed axis of oscillation, and a sleeve bearing member between the aforesaid sleeve bearing elements and between the mid-portion of the hollow rocker structure and the hub of the other rocker structure for journaling the latter for anti-friction rocking movement about the fixed axis of oscillation aforesaid, said hollow rocker structure having a valve-engaging finger structure aflixed to the splines of the splined section thereof, and said other rocker structure including a valve-engaging finger structure presenting a plurality of fingers divergently separated at one end and having a common portion at the opposite end integrally joined to the said other rocker structure.

References Cited in the file of this patent UNITED STATES PATENTS Fuchs May 9, Pielstick Sept. 16, Witzky et a1. Nov. 25,

FOREIGN PATENTS France Sept. 19, Great Britain Mar. 16, Switzerland Jan. 16, Germany Dec. 28, Netherlands June 16,