US2095968A - Internal combustion engine - Google Patents

Description

Oct. 19, 1937. w. K, ES 5 2,095,968

7 INTERNAL COMBUSTION ENGINE Filed June 24, 1932 2 Sheets-Sheet 1 lNl/e-zv-ro 1 14441.75)? Kfiunosss 1 Oct. 19, 1937. 'WQK. BURGESS r 2,095,968

INTERNAL coueusrron iimnm' Una ig;

Patented Oct. 19, 1937 UNITED STATES arenas PATENT INTERNAL COMBUSTION ENGINE Walter K. Burgess, United StatesArmy,

'Chanute Field, Rantoul, Ill.

Application June 24, 1932, SerialNo. 619,116

2 Claims.

(Granted under the act of March 3, 1883, as amended April 30, 1928; 370 O. G. 757) The invention described herein may be manufactured and used by or for the Government for governmental purposes, Without the payment to me of .any royalty thereon.

5 This invention relates to an improved crank shaft for internal combustion engines of the multiplecylinder type and the basic idea of the same is in the coupling of an inherently balanced crank-shaft unit, consisting of an uneven number of throws or cranks, with an internal combustion engine of an even number of functions or strokes per cycle.

All present internal combustion engines of a reciprocating nature have embodied the following basic errors in their constructions, 1st:

Vibrati0n, and 2nd:-Such crank shafts as have hitherto been employed have not of themselves been inherently balanced units owing to the employment of crank arms or crank-cheeks. For this reason, they require the addition of unf necessarily heavy fly-wheels and counterweights in an effort to overcome the periodic stresses of compression, power, scavenging and intake cycles, set up and dueto the conditions above outlined.

It is an=object ofthe present invention to elimgs inate the disadvantages enumerated above by providing a crank shaft which is centrifugally and inherently balanced without use of any fly wheel or counterweights and which includes, among other features, the arranging of the va- 40*"rious-crank shaft parts so as to provide a complete structure having the physical characteristics and the inherent static and dynamic balance of a' true cylinder or roller. The invention further contemplates the employment of an odd 45*number of cylinders or power units composed of an even number of functions or strokes per cycle, and also in the complete abandonment of the accepted practice of endeavoring to balance each throw, pair or group of throws and in lieu therei 50 of to compose and assemble a shaft of single crank pins and main bearing spool-like gyroscopic units which collectively form a true and inherently balanced crank shaft.

Another'object of the invention is to provide 551101 a definite progressive fractional over-lapping or stepping through of the cycle sequences in an even cycle motor, thereby breaking up and damping out any periodic meter or rhythm of vibration common to.al1 motors without this principle. It is similar to the old and simple ex- 5* pedient of placing troops out of step when crossing a structure peculiarly subject to vibration.

A further object of the invention is to provide means whereby the fly wheel principle is contained actually within the crank shaft structure 10 itself and distributed evenly and longitudinally throughout the structure as an inherent part thereof, and to provide, also, through a multiplicity of natural evenly spaced main bearings,

a feasible, practical and equitable loading of 15 these bearings, whereby complete ball or roller main bearings may be used throughout the crank shaft.

A still further object of the invention is to provide for the application to a crank shaft structure of a. definite, continuous, longitudinal combination of a gyroscopic and roller principle in preventing and damping out the flexing of such a shaft during the application and removal of the power stroke stresses or the similar but 5 lesser stresses of the otherstrokes of either two or four cycle engines. Again, the invention aims at an improved torque on the crank shaft and provides means of more easily approaching the conditions of true turbine torque and affords means of controlling torque distortion.

With the foregoing in view, the invention comprises the features and combination of parts hereinafter more fully set forth and described,

with reference to the accompanying drawings whereinz- Figure 1 is an end view of a three-throw solid crank shaft constructed in accordance with the 7 principles of the invention;

Figure 2 is a side view thereof, with the crank 40 shaft parts in disjointed relation;

Figure 3 is an end view of a five-throw solid crank shaft embodying the invention;

Figure 4 is a side view of the crank shaft shown in Fig. 3;

Figure 5 is a perspective view, on an enlarged scale, of the five-throw hollow crank shaft;

Figure 6, is a longitudinal sectional view of the five-throw hollow crank shaft;

Figure '7 is an end view of the hollow crank shaft;

Figure 8 is a longitudinal sectional view of an internal combustion engine and crank shaft constructed and assembled in accordance with the invention.

This crank shaft is characterized by the absence of any fiy wheel or crank arm throws in the conventional sense or any balancing element outside the crank shaft structure itself and this latter is contained within a conventional crank case, as shown in Fig. 7.

The crank shaft is composed of an even number of gyroscopic discs I, an even number of main bearing or crank journals 2, and an. odd number of connecting rod journals or crank pins 3, the latter being of the same diameter as the main bearing journals. The discs I are arranged in a longitudinal series concentrically true about the axis of rotation of the shaft and each disc is of uniform thickness throughout its surface area.

As shown in the several views of the drawings and more particularly in Fig. 1, the two end discs of the series, indicated at la and lb respectively, include the two end crank journals 2a and 22) respectively, while the intermediate discs and crank journals are so relatively connected as to provide spool-like gyroscopic units A, B, etc., each unit comprising a pair of discs I connected by a main bearing journal 2. As shown in the drawings, the main bearing journals 2 and the crank pins 3 merge into the discs I through fillets f in the right angles. This disperses the stress, greatest at these points, over the maximum area. The spool-like units A, B, etc. connected to each other, and to the end discs I a and lb, by the crank pins 3 which are disposed about the axis of the crank shaft and distributed on separate and different longitudinal planes, in uniformly spaced relation, to provide a concentric progression of throw planes preferably of odd number and equal in number to the number of cylinders, thus affording substantially a turbine-like torque and more effectively balancing the crank shaft.

As will be readily perceived, from an inspection of the five-throw crank shaft illustrated in Fig. 5, and from the end views of Figs. 1 and 3, the construction and grouping together of crank shaft parts in the manner above described renders the completed crank shaft 2. true cylinder of discs with the connecting crank pins or throws placed in a true geometric star-like figure of an uneven number of points about the main bearing axis. The total assembly, therefore, has the physical properties and the inherent static and dynamic balance of a cylinder or roller and its structural principles afford naturally a plurality of equallyber of discs, crank pins, or journals etc., or turned from a forging, then quenched or case-hardened and ground. The crank shaft design lends itself, also, to manufacture by drop forging, milling and turning and grinding; no planar or shaper work being involved, its manufacture after drop forging or rolling being simply lathe work on the different centers. To make the crank shaft hollow, as shown in Fig. 6, and at the same time in no Way disturb its inherent symmetry and balance, both static and dynamic, it is drilled longitudinally throughout the entire structure, through the shaft and through each throw plane axis, or the axis of each crank pin. Uniform leads 0 are drilled through the disk sides adjacent to each crank pin, tapping or connecting with the central hollow shaft reservoirs. The ends, naturally, of each crank pin are plugged as at d. Since this structure is progressive, each and every disk then would show all the holesopen, except those at the point of the crank pin for that throw. This method, first of all, makes for uniformity and lends itself to quick manufacture. It further lightens the shaft structure without weakening it, and is in harmony with the Whole underlying principle of the crank shaft, that is, an assemblage of inherently unbalanced fractional parts, the sum total of Which comprise an inherently static and dynamically balanced integer.

In all internal combustion engines embodying an even number of cylinders with an even number of strokes per cycle, a definite and fixed rhythm or vibration is set up as a result of the periodic stress power, scavenging, and intake strokes. By coupling an inherently balanced crank shaft, consisting of an uneven number of throws or cranks, with an internal combustion engine consisting of an odd number of cylinders or power units of an even number of strokes per cycle there will be a definite progressive fractional overlapping or stepping through of the cycle sequences, thereby breaking up and damping out the tendency common to all motors, to set up a periodic meter or rhythm of vibration.

Figure 8 illustrates one application of this principle of the invention and shows the employment with an internal combustion engine, having an uneven number of cylinders, of an inherently balanced crank shaft of gyroscopic discs and an uneven number of crank throws. The use of a series of discs throughout the crank shaft, instead of the conventional crank arms or checks, divides the fly wheel and counter-balance weight evenly throughout the length of the shaft, thereby loading all main bearings evenly. Each disc, in fact, is equivalent to a proportional part of the conventional fly wheel and by means of the discs the fiy wheel principle is contained actually within the crank shaft structure itself and distributed evenly and longitudinally throughout that structure as an inherent part thereof in disc-like increments. Furthermore, each disc acts like a gyroscope in principle, resisting the bending moment in the crank shaft, through the bearing clearance limits, during the application and removal of the power impulse. Compression, scavenging and intake impulses exert similar bending moment of greatly lessened degree. A gyroscope in rotation tends to ride up against a force exerted at a right angle to its plane of rotation. This law incorporated within a crank shaft design provides means within the crank shaft itself for counteracting the tendency to spring or flex the shaft twice during each power cycle; during the almost hammer-like blow when the power cycle starts and the abrupt suspension of that force when the poppet type of exhaust valve is opened. There is, also, a definite stiffening of the whole crank shaft structure throughout its longitudinal axis by means of the gyroscopes distributed equally and in pairs on either side of each stressed point along that axis.

Each main bearing journal, its component discs, and the crank pins with right angular fillets connecting the several parts provide for the maximum strength factor in conjunction with the minimum Weight factor by reason of .distributing the stresses, inherent in any crank shaft about the main bearing and crank pin angles, throughout the widest possible area and over a greater area than is possible with the narrow conventional cheek type of crank throw or counterweighted disc. The assembled structure is such that each pair of discs with its component crank pin becomes an unbalanced integer, the sum of which unbalanced integers results in an inherently balanced integer in such a manner that a gyroscopic action is imparted to the shaft on each side of each connecting rod pin to oppose the flexing of the crank shaft within its bearing tolerance limits while in operation, thereby imparting to the structure increased inherent running bal ance whereby its longitudinal deflection and torque, and the consequential vibration, will effectively be controlled.

Any reciprocating motor using a crank shaft of this design is, providing the connecting rods and piston assemblies are uniform, as nearly in balance as is possible in such reciprocating mechanism. v v

Having thus described the invention, What is claimed is:

1. In an internal combustion engine, the combination with an odd number of in-line power units embodying an even number of functions of a crank-shaft having a corresponding odd number of inherently unbalanced crank throws equally spaced longitudinally of the crank-shaft, said crank throws comprising respectively a pair of relatively spaced apart parallel gyroscopic disks connected together adjacent their rims by a crank-throw pin, the pins of all the crankthrows being radially equi-distant from the axis of the crank shaft and so relatively arranged as to extend in equal longitudinally consecutive progression around the shaft to collectively balance the shaft statically and dynamically and providing for a definite progressive fractional overlapping of all the impulses, especially the firing impulses, whereby any fixed period or meter of vibration is continually progressively and fractionally stepped into and passed through and broken up.

2. A multiple cylinder internal combustion engine having, in combination, an odd number of cylinders in a straight line with each cylinder adapted to perform its cycle in an even number of strokes, and a crank shaft composed of a plurality of laterally and equidistantly spaced gyroscopic disks equal in number to twice the number of cylinders with crank pins and main journal bearings between and connecting successive pairs of disks in an alternate arrangement providing the same number of individually unbalanced cranks as there are cylinders with each unbalanced crank consisting of two disks connected by a crank pin and with the crank journals located at the ends of the shaft and also between and connecting successive cranks, said unbalanced cranks being consecutively and equally spaced about the axis of the shaft to collectively balance the latter statically and dynamically and WALTER K. BURGESS.

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