US1993992A - Internal combustion engine - Google Patents

Description

H. FORD 1,993,992

INTERNAL COMBUSTION ENGINE March 12, 1935.

Filed NOV. 21; 1952 2 Sheets-Sheet l ATTORNEY.

INVENTOR.

March 12, 1935. FORD 1,993,992

INTERNAL COMBUSTION ENGINE Filed Nov. 21, 1932 2 Sheets-Sheet 2 INVENTOR.

ATTORNEY.

Patented Mar. 12, 1935 PATENT OFFICE INTERNAL COMBUSTION ENGINE Henry Ford, Dearborn,

Mich., assignor to Ford Motor Company, Dearbom, Mich., a corporation of Delaware Application November 2 4 Claims.

The object of my invention is to provide an internal-combustion engine of high thermal and mechanical efficiency and one which may readily be assembled in perfect precision by inexperienced 5 labor.

More specifically, .the object of my invention is to provide an internal-combustion engine of the overhead valve type, which valves are operated directly by an overhead cam shaft and which cam shaft is drivenfrom the crank shaft of the engine by a novel gear train. There are several features in my engine which are each believed to be of novel construction and which each materially adds to the simplicity and reliability of the engine.

The general arrangement of my improved engine comprises a vertical cylinder block having a crank shaft rotatably mounted beneath the cylinders so as to be rotated by the reciprocation of the pistons therein in the conventional manner.

. An .auxiliary shaft is rotatably mounted in substantial alignment with the crank shaft at the forward end of the engine, this auxiliary shaft being driven by the crank shaft through a universal movement joint. The auxiliary shaft is provided with a spiral bevel pinion which meshes with and drives a spiral gear at right angles thereto, the axis of which is vertically aligned, at one-half the speed of the crankshaft. The drive from this spiral gear is transmitted through a vertical shaft up to the top of the engine cylinder block. A short shaft is rotatably mounted in the cylinder head in alignment with the first mentioned vertical shaft and a second pair of spiral bevel gears, one on the upper end of the short vertical shaft and the other secured to the forward end of the cam shaft completes the drive for the cam shaft.

The several features of importance in this construction are:

First, I have provided a novel cam shaft gear housing which is aligned from the crank shaft bore in the cylinder block and in which housing the lower pair of spiral bevel gears are rotatably mounted. Due to the universal connection between the auxiliary shaft and the engine crank shaft, endwise movement or slight variations in the alignment of the crank shaft will not affect the alignment of the gears for driving the cam shaft.

Second, I have provided a unique cylinder head construction wherein the valves, cam shaft and cam shaft driving gears are all mounted in accurate relation to each other so that they may be removed as a unit from the engine without 1, 1932, Serial No. 643,701

disturbing their alignment. In this connection it may be well to mention that I have provided a clutch capable of assembly in only one position which operatively connects the two vertical shafts so that the cam shaft drive is automatically accomplished when the cylinder head is placed in position on the cylinder block. Thus, the cam shaft driving gears, if aligned accurately when the engine is manufactured, will stay in this accurate alignment irrespective of wear of the crank shaft hearings or a slight misalignment of the cylinder head on the cylinder ,block.

I have also provided a unique device for connecting the cam shaft bevel gear to the cam shaft in any of an infinite number of positions. Inasmuch as the cam shaft must be removed from the cylinder head when the valves are reground, it is desirable to provide a convenient way whereby inexperienced persons may accurately retime the engine. To do this I have provided a cap over the rear end of the cam shaft which may be reversed, in which positionit coacts with a slot machined in the cam shaft to thereby fixedly locate the cam shaft in the cylinder head. Conventional means are provided for locating the crank shaft in a predetermined position so that after both the crank shaft-f and cam shaft have been located then the cam shaft bevel gear may be secured in place to thereby retain the engine in its correct valve-timed position.

Still a further feature of this engine is the novel distributor drive wherein the distributor is driven directly from the vertical driving shaft, thus maintaining the timing of the ignition of the engine independently of the cam shaft. It has heretofore been the practice in overhead cam shaft engines to drive the distributor directly from the cam shaft, while in my improved engine the distributor is driven independently of the cam shaft. The advantage of my construction is that the removal of the cylinder head from the engine will not alter the ignition timing of the engine.

Still a further feature of great importance in connection with this-engine is the novel oiling system incorporated therein, whereby oil is circulated to every bearing of the engine and wherein the circulation of this oil is accomplished in a more positive manner than has heretofore been accomplished. In such engines it has been customary to provide an oil pump driven through gears or other driving connections from the engine crank shaft. However, such pumps are always subject to failure due to breakage or fallure of the driving connection from the engine and further it sometimes happens that when such engines are overhauled the mechanic fails to install the oil pump back in place, the result being that upon the operation of the engine the bearings are ruined, pistons scored and the engine seriously damaged. In my improved engine the oil pump is formed integral with the rim of the flywheel and cannot be separated therefrom so that under all circumstances when the engine is operating the oil pump must function to deliver oil to all working parts of the engine. This oil pump has the further advantage of being much cheaper to construct than the conventional oil pump.

With these and other objects in view my invention consists in the arrangement, construction .through the rear portion of the engine, illustrating the oiling system used therein.

Figure 3 shows a full-sized view of a portion of the flywheel rim and associated section of the cylinder block, illustrating the operation of the oil pump used herein.

Figure 4 shows a plan view of the plate which drives the auxiliary shaft from the crank shaft, and

Figure 5 shows a sectional view taken on the line 5-5 of Figure 1.

Referring to the accompanying drawings, I have used the reference numeral 10 to indicate generally the cylinder block of an automobile engine, this block having a plurality of cylinder bores 11 therein in which pistons 12 are reciprocally mounted in the conventional manner. Spaced beneath the lower ends of the cylinders 11, a plurality of relatively large main bearings .13 are machined in the block 10, there being a bearing disposed between each of the cylinders. The crank shaft used in this engine is described more fully in a separate patent application. However, it may be suflicient to say that this shaft is formed from a plurality of relatively large discs 14 each of which is aligned with one of the main bearings 13 and which discs are secured together by crankpins 15 formed integrally therewith. It will be noted that the discs 14 are slightly larger than the path described by the crank pins 15 whereby the shaft may be inserted axially I through the main bearing bores 13 of the cylinder block. Thus, it is not requiredthat the bearings 13 be of the split type to assemble the shaft to the cylinder block. Due to the large area of the bearings 13 the unit area pressure on these main bearings is very low so that the bearing wear during the normal life of the engine is almost negligible. Of course each of the pistons 12 is connected to the adjacent crank pin bearings 15 by means of conventional connecting rods 16.

A novel feature of this construction is that the crank shaft does not project beyond the two end bearings 13. A flywheel 17 is fastened to the rear end of the crank shaft by means of cap screws 18 and prevents forward movement of the crank shaft, while a driving plate is secured to the forward end of the crank shaft by cap screws 20 and prevents rearward movement of the crank shaft. However, due to the expansion of the shaft whenheated up to its operating temperature there is allowed a small longitudinal movement of the shaft when operating.

. It will be noted that this engine is provided with an overhead cam shaft which is rotated at one-half the enginespeed by means of a spiral bevel gear train, which train is located in a vertical passageway 21 cast in the cylinder block parallel to the front cylinder of the engine. The front end of the engine is bored out at 22 in line with the bearings 13 and a housing 23 is piloted in the bore 22, this housing having a bearing 24 concentrically formed therein in which an auxiliary shaft 25 is rotatably mounted. The driving plate 19 is provided with a slot 26 slightly offset diametrically, in which slot the flatted end 27 of the shaft 25 extends whereby rotation of the driving plate drives the shaft 25. A pilot bearing 28 is provided on the shaft 25 which extends into an axial bore 29 in the crank shaft proper to axially align the shaft 25 with the crank shaft. 'Longitudinal movement of the shaft 25 relative to the crank shaft is permitted by this construction and in fact a limited universal movement between the shafts is permitted.

The forward end of the shaft 25 projects outwardly through the housing 23 and a water pump and fan-driving pulley 30 is secured to this outer end of the shaft.

Fixedly secured on the shaft 25 just inside of the bearing 24, I have provided a spiral bevel pinion 31, which pinion is in mesh with a spiral bevel gear 32, this gearing being fixedly secured on the lower end of a vertical shaft 33 which shaft is rotatably mounted in the housing 23 at right angles to the shaft 25. Due to both the shafts 25 and 33 being rotatably mounted in the same housing it follows that if the gears are initially aligned in their correct position this desired aligmnent will remain unaflected by slight variations in the alignment of the engine crank shaft. This is a very important feature where quietness of operation is required as this housing maintains the correct alignment of the pinion 31 and gear 32 irrespective of serving, wear or slight misalignment of the engine. In the past it has been customary to mount the crank shaft gear directly upon the crank shaft and then in some way attempt to prevent axial and radial movement of the shaft. The disadvantage of such structure was that it was almost impossible to prevent the crank shaft from moving radially and axially.

Still further, the permissible running clearance between the crank shaft and its bearings, is much greater than is permissible for a quiet gear drive. This may be brought out by stating that on large engines a clearance up to twenty thousandths of an' inch is required in the crank shaft bearings so that these bearings may be adequately cooled, while a variation of twenty thousandths of an inch in the axial or radial alignment of the bevel gears prohibits the quiet operation of the gears. In the applicant's device the alignment of the gearing is secured independently of the crank shaft alignment so that if the gear drive is quiet when it is manufactured, then servicing of the engine or Wear of the crank shaft bearings will not cause the gearing to lose its quietness of operation.

Referring now to the upper portion of the enture of this valve construction is that the cylinderhead is provided with a relatively large bore 39 around each valve spring in which inverted cupshaped tappets 38 are reciprocally mounted with the rim of the cup member extending down into its bore 39 while the end of the valve stem bears directly against the bottom of the cup member. Thus, reciprocation of the tappets directly reciprocate the valves 35 against the action of the valve springs 37. Inasmuch as a conventional cam shaft is used to reciprocate the tappets 38, it will be seen that these tappets absorb the side thrust produced by the cams on the cam shaft to thereby eliminate side thrust from the valve stem and thus prolong the life of the valves and valve bushing and assure their alignment during the life of the engine.

The cam shaft associated with this engine is given the reference numeral 40 and is of the conventional type having a plurality of cams 41 disposed thereon aligned with-the tappets 38, this shaft being rotatably mounted in the upper portion of the head 34. The forward end of the cam shaft extends into a chamber 42 formed in the cylinder head just above the vertical passageway21 of the cylinder block and a spiral bevel gear 43 is nonrotatably secured on the end of the cam shaft within this chamber. The gear 43 is not keyed to the shaft but is secured thereto by means of a tapered split ring 44 which is forced into a tapered bore in the gear by means of a suitable nut 67 threaded on the the end of the cam shaft. Thus, when the nut is loosened the gear may be moved to any angular position relative to the cams on the shaft and then by tightening the nut the gear is fixedly secured to the shaft in this adjusted position. The purpose of this construction is to assist in timing the valves of the engine and will be more fully brought out later in the specification.

A vertical shaft 68 is rotatably mounted in the cylinder head in substantial alignment with the shaft 33'and a spiral bevel gear 45 is formed integrally with the upper end of this shaft 68 and located to mesh with the gear 43. The drive ratio between gears 43 and 45 is one-to-one so that an ignition distributor may be operated directly from the shaft 68. A coupling 46 is nonrotatably secured on the lower end of the shaft 68 by means of a nut 47, this coupling having a flat therein, not shown in the drawings, whereby the coupling may be'assembled to the shaft 68 in only one angular position. The adjacent end of the shaft 68 is flatted and coacts with a flat milled on one side of the coupling to obtain this predetermined relation between the coupling and the gear 45. The upper end of the shaft 33 is provided with a portion 48 of reduced diameter which engages a suitable bore in the lower end of the shaft 68 to thereby align the adjacent ends of the shafts. The upperend of the shaft 33 is also provided with a two-toothed clutch 49 which engages the coupling 46 and thus completes the drive between the shafts.

It will be noted from Figure 5 that the teeth of the clutch 49 are offset diametrically from the shaft 33 so that the coupling may be assembled in only one angular position relative to the shaft 33. Thus, when the cylinder head is removed from the cylinder block, the coupling 46 simply draws out away from the shaft 33 there being no bolts, connections or other apparatus to remove, and that when the head is in its removed position, the tooth alignment between either set of gears is in no way disturbed. Any slight misalignment that may occur between the cylinder head and cylinder block when the head is reassembled is automatically compensated for by the coupling 46 so that if the gears 43 and 45 are originally aligned so as to operate quietly then the slight variations unavoidable in the assembling of the cylinder head will in no way effect this alignment to alter the quietness of this gearing.

An opening is provided in the upper portion of the chamber 42 which is adapted to be closed by an ignition distributor 50, the distributor having its operating shaft extending down in position adjacent to the top of the gear 45. The lower end of this distributor shaft is provided with a diametrically offset tongue 51 which engages a complementary proportioned slot in the gear 45 whereby the distributor is directly driven by the shaft 68 independently of the cam shaft of the engine. The tongue 51 and driving slot offset from the axes of the two shafts so that the distributor can only be assembled in only one angular position relative to the shaft 68.

It is believed that the arrangement whereby a vertical shaft is driven at one-half the engine speed through a suitable gear reduction associated with the crank shaft of the engine and wherein the distributor is directly driven from the upper end of this vertical shaft is new. Several advantages arise from this construction, one being that the distributor is placed in a much more accemible position, however, the main advantage is that the ignition timing of the distributor is accomplished independently of the timing of the cam shaft. This is a very desirable feature in overhead cam shaft engines for the reason that in regrinding the valves, usually the cam shaft must, be removed and if the ignition distributor is gear driven from this shaft it is necessary to retime the ignition after assembling the cam shaft in place.

In this engine the distributor can only be assembled in place in one position relative to the engine crank shaft so that unless the lower set of gears are actually removed from the housing 23, which operation is not required even in completely dismantling the engine, then upon reassembling the cylinder head and distributor the mechanic may be assured that the ignition timing is correct. In fact, the lower set of gears are in actual practice assembled and marked in the factory by means of accurate jigs and fixtures so that the servicing mechanic cannot put the engine together in any other but the exact correctly timed position. This is believed to be a vast improvement over all former type engines in which the mechanic was required to time the ignition upon each removal of the cylinder head from the engine. Experience has proven to the applicant that it is too much to expect even a skilled mechanic without special fixtures or jigs to accurately locate the angular position-of the relatively small distributor cam, so that he believes this motor not requiring distributor timing in service to be materially superior from a service standpoint.

Referring now to the means for timing the valves after assembly of the cam shaft in the cylinder head, it will be noted from Figure 2 that the rear end of .the cam shaft is provided with a diametrically offset tongue 52 and that's.

cover plate 53 is detachably secured as shown over the rear cam shaft bearing of the cylinder head. The cover plate 53 is provided with a slot 54 complementary to the tongue 52 which extends rearwardly from the cam shaft. The

cover 53 normally does not coact with the tongue 52 of the cam shaft. However, when it is required that the. cam shaft be accurately timed relative to the position of the crank shaft, the nut 67 on the forward end of the cam shaft is loosened thereby loosening the cam shaft, and then the cover plate 53 is turned over so that the slot 54 engages the tongue 52 and then the cover plate and cam shaft are rotated as a unit until vthe retaining bolts on the cover plate become aligned with their respective openings. It may be well to mention that these bolts are unevenly spaced aroundthe periphery of the cover plate so that the plate may be secured into the cylinder head in only one angular position.

The engine flywheel is provided with a small drilled hole therein not shown in the drawings which may be readily aligned with a hole in the flywheel housing when the shaft is rotated to a predetermined position, preferably where the number one piston is on top dead center. The insertion of a pin through these two holes eaccurately positions the flywheel. .Other means may be provided for centering the crank shaft such as marking the periphery of the flywheel and aligning the mark with a pointer on some portion of the housing around the periphery.

- of the distributor is in no way altered.

Referring now to the means for oiling the various parts of the engine it will be noted that I have provided right and left hand spiral grooves 55 and 56, respectively, around the periphery of the flywheel 1'7. The periphery of the flywheel adjacent to these grooves rotates in and closely fitted to a cylindrical bore in the cylinder block and inasmuch as the lower portion of this flywheel is located beneath the normal oil level of the engine, it follows that ro= tation of the engine in its normal direction of operation will cause oil to be forced from the front and rear edges of the flywheel inwardly towards the grooves 55 and 56. v A conduit 57 is drilled in the cylinder block from the intermediate portion of the cylindrical bore which surrounds the grooves 55 and 56, which conduit extends upwardly where it is aligned with a conduit 58 drilled in the cylinder head and which conduit 58 extends upwardly to the chamber in which the cam shaft rotates. Consequently, when the flywheel is being rotated in its normal operating direction oil is forced inwardly from both the front and rear faces of the flywheel towards the center and consequently is forced upwardly through the conduits 57 and 58 to the cam shaft where it oils the cam shaft bearings and valve tappets. The oil then flows forwardly as shown by the arrows in Figures 1 and 2 and discharges down over the gears 43 and 45 also lubricating the bearings of the vertical shaft 68.

The chamber 42 being open on the bottom allows the oil to flow downwardly through the passageway 21. The housing 23 is provided with a shroud 59 which collects a portion of the oil and conducts it through oil holes 60 and 61 to the respective bearings in the housing 23. The overflow of oil fromjtheshroud 59 then flows down and collects on a dip trough 62 from which it flows to the rear portion of the engine. The trough 62 is provided with sumps 63 adjacent to and aligned with each connecting rod 16 whereby dippers formed on the lower ends of these connecting rods may in the ordinary manner lubricate the crank pin bearings and the pistons 12. It will also be noted that the oil which collects on the sides of the crank shaft discs may be thrown centrifugally into holes 64 in the periphery of each disc to thereby lubricate the main bearings 13 of the engine. The oil after traversing the length of the trough 62 overflows from the rear end thereof and collects in the oil reservoir which forms the bottom of the engine.

A feature of considerable importance in connection with the oiling of the overhead cam shaft and valve tappets is that a longitudinally extending conduit 65 extends the length of the cylinder block adjacent to the bottoms of the bores 39 in the cylinder head: The rear end of the conduit 65 intersects a vertical conduit 66 whereby oil which leaks down through the tappet bearings may collect in the conduit 65 and flow by gravity to the conduit 66 from which it flows downwardly through a suitable conduit in the cylinder head and block to the oil reservoir. Thus, the cam members 41 and valve tappets 38 may be supplied with an excessive amount of oil and while some of this oil will no doublt leak down through the tappet bearings, still the oil so used will not burn up or be lost but will always drain out through the conduit 65 to prevent the leakage of oil down around the valve stem and into the intake exhaust ports of the engine. Heretofore, the flow of oil to such tappets was required to be regulated so that an excessive amount would not be present as otherwise the oil would seep down around the valve stems into the exhaust chambers thereby not only burning up oil but causing disagreeable smokeand odor from the engine. The provision of the draining conduit 65 in this device allows oil to practically fill up the chamber in which the cams operate, which provision would not be permitted in any other engine known to the applicant.

Among the many advantages arising from the use of my improved engine, it may be well to mention that I have provided an engine having a novel crank shaft therein and which may be inserted into place axially from either end of the engine.

Further, the provision of self-contained cam shaft drive gear assembly which is universally connected to the crank shaft is believed to be new and insures the quiet operation of the engine irrespective of the wear that may develop on the crank shaft or other parts of the engine.

Still a further advantage results in that the novel arrangement of the distributor gear train permits flxed timing of the distributor in spite of the fact that the cam shaft must be removed when grinding the valves.

Still a further feature comprises the unique ment, construction and combination of the various parts of my improved device without departing from the spiirt of my invention and it is my intention to cover by my claims such changes as may reasonably be included within the scope thereof.

I claim as my invention:

1. An internal-combustion engine having a crank shaft and cam shaft each rotatably mounted therein, a gear housing aligned in said engine independently of the crank shaft of -the engine, said housing having a plurality of gears rotatably mounted therein which are operatively connected to transmit rotation to said cam shaft, said housing having an upwardly extending shroud formed therearound which functions to collect oil and conduct same to the gearing associated with the housing, and a flexible connection disposed between said crank shaft and one of the gears in said housing, whereby a limited movement of the crank shaft relative to said gear housing is provided for the purpose described.

2. Internal-combustion engines having a crank shaft rotatably mounted therein, an overhead cam shaft rotatably mounted in said engine, a vertical shaft rotatably mounted in said engine and connected by bevel gears to drive said cam shaft, the lower end of said vertical shaft being rotatably mounted ina housing which is detachably secured to said engine in substantial alignment with said crank shaft, an auxiliary shaft rotatably mounted in said housing in substantial alignment with said crank shaft, bevel gears connecting said auxiliary shaft and vertical shaft, said housing having an upwardly extending shroud formed integrally therewith which functions to collect oil and conduct same to said vertical and auxiliary shafts, and a flexible joint connecting the crank shaft and said auxiliary shaft, whereby a limited movement of the crank shaft relative to said auxiliary shaft is' permitted for the purpose described.

- 3. A cam shaft drive for internal combustion engines comprising, a driving plate secured to one end of the engine crank shaft, said plate having a transverse slot therein which extends across its center portion, said crank shaft being provided with an axial opening therein adjacent to said plate, a driven shaft rotatably mounted in said engine in substantial. axial alignment with the engine crank shaft, the adjacent end of said driven shaft fitting into the axial opening in the engine crank shaft while an intermediate portion of the driven shaft is flatted to fit into said slot to thus form a flexible driving connection between the crank shaft and said driven shaft, and

, means for driving the engine cam shaft from said driven shaft.

4. A device, as claimed in claim 3, wherein the center of said slot is spaced radially from the axis of the crank shaft whereby the flatted portion of said driven shaft may be assembled into said slot in only one angular position.

. HENRY FORD.

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