US2731960A

US2731960A - Internal combustion engine with die cast block

Info

Publication number: US2731960A
Authority: US
Publication date: 1956-01-24
Anticipated expiration: 1973-01-24

Description

Jan. 24, 1956 R, N. KIRCHER ET AL 2,731,960

INTERNAL COMBUSTION ENGINE WITH DIE CAST BLOCK Filed Oct. 29, 1952 4 Sheets-Sheet 1 F le. 3

INVENTORS RALPH N. K IRCHER Y HERMAN D. PALMER A-r-ronuev Jan. 1956 R. N. KIRCHER ET AL 2,731,960

INTERNAL. COMBUSTION ENGINE WITH DIE CAST BLOCK 4 Sheets-Sheet 2 Filed Oct. 29, 1952 Fla.

INVENTORS RALPH N. Kmcm-za HERMAN D. PALMER WMW ATTORNEY J 1956 R. N. KIRCHER ETAL 2,731,960

INTERNAL COMBUSTION ENGINE WITH DIE CAST BLOCK Filed Oct. 29, 1952 4 Sheets-$heet 3 I26 I36 (28 Fla. 9

I38 Zoo I54 |58 am am INVENTORS RALPH N. KmcHeR BY HERMAN D. PALMER WMW ATTORNEY Jan. 24, 1956 R. N. KIRCHER ET AL 2,731,960

INTERNAL COMBUSTION ENGINE WITH DIE CAST BLOCK Filed Oct. 29, 1952 4 Sheets-Sheet 4 Fl ca. l3

INVENTORS F? RALPH N. K\RCHE.R BY HERMAN D. PALMER ATTORNE-Y INTERNAL CQMBUS'HUN ENGINE WITH DIE CAST BLUCK Ralph N. Kircher, West Bend, and Herman D. Painter, Hartford, Wis., assignors to West Bend Aluminum (10., West Bend, Wis., a corporation of Wisconsin Application Uctober 29, 1952, denial No. 317,512

4 Claims. (Cl. 123-195) This invention relates to improvements in internal combustion engines particularly to air-cooled engines having die cast blocks.

Many economies are effected by a die casting operation. But heretofore only a part of the possible savings have been obtained because only a part of the crankcase was cast with the cylinder block. This necessitated additional complex machining operations in order to have the crankshaft bearings properly alined and the resulting engine was not rigid and strong.

It is an object of this invention therefore to provide an engine of this type which may be made by die casting to obtain the fullest economies and is light, strong and rigid.

This object is obtained by die casting the engine block with the cylinder, cylinder head, cooling fins, fuel trans fer passage, cylinder wall insert if any, and all of the crankcase as one piece. The engine block is cored so that both the cylinder-forming die and the transfer passage-forming die may be removed through a bottom or piston opening in the crankcase. The dies for the bearing cage opens are withdrawn laterally of the engine block along the axis of the crankcase; hence there is established a fixed and rigid alinement for each crankshaft bearing. Any required machining is relatively simple and the casting may be easily set up for drilling, boring, honing, or facing.

To assemble the engine the piston and piston rod assembly is first introduced into the cylinder through the piston opening in the bottom of the crankcase. The crankshaft is then inserted through the bearing cage openings in the crankcase and the connecting rod bearing cap bolted in place to secure the rod and crank. The hearing cages are then fitted on the crankshaft and bolted rigidly in place in the bearing cage openings. Members comprising a reed valve plate and a carburetor connector are then bolted to the crankcase over the piston opening. The crank and connecting rod hearing, before the bearing cages are placed on the crankshaft, may be positioned eccentrically of the bearing cage openings so that the crank and bearing cap projects out through the piston opening, making assembly of such cap very easy. However the piston opening is large enough so that the connecting rod bearing cap can be easily assembled even if the bearing cages have been put in place and the crankshaft centered.

Several of such blocks can be used with a single crankshaft. In such case, center main bearing cages with crankshaft bearings are mounted on the crankshaft be tween the cranks. Each cage fits into the bearing cage openings of adjacent blocks and is gripped between such blocks which are held by through-rods passing through arms on each block and each outer bearing cage.

In one modification of the invention the intake and exhaust ports are on the same sides of the block as the bearing cage opening and the fuel transfer passage is formed by the same laterally removable die which forms one of the bearing cage openings. In such modification the bearing cage has an extension which forms the outer wall of such transfer passage.

In another modification there is only one bearing cage opening and the opposite wall of the crankcase has an integral cylindrical projection which forms the support for the other crankshaft bearing.

The novel features, which are considered characteristic of the invention, are set forth with particularity in the appended claims. The invention itself, however, both as to its organization and its method of operation, together with additional objects and advantages thereof, will best be understood from the following description of specific embodiments when read in connection with the accompanying drawings, in which:

Fig. l is a view in vertical cross-section of an internal combustion engine embodying the present invention;

Fig. 2 is a sectional view taken on the line 2-2 of Fig. 1;

Fig. 3 is a fragmentary view in right side elevation taken from the line 3-3 of Fig. 1;

Fig. 4 is a sectional view taken on the line 4-4 of Fig. 2;

Fig. 5 is a sectional view taken on the line 5-5 of Fig. 2;

Fig. 6 is a fragmentary View in left side elevation taken from the line 6-6 of Fig. 1;

Fig. 7 is a view in vertical cross-section of an internal combustion engine embodying a modification of the present invention;

Fig. 8 is a View in left side elevation taken from the line 8-8 of Fig. 7;

Fig. 9 is a fragmentary sectional view of an internal combustion engine embodying a second modification of the present invention;

Fig. 10 is a fragmcntary view in right side elevation taken from the line 10-10 of Fig. 9;

Fig. 11 is a view partly in front elevation and partly in vertical section of an internal combustion engine embodying a third modification of the present invention;

Fig. 12 is a fragmentary sectional view taken on the line 12-12 of Fig. 11, and

Fig. 13 is a fragmentary View in right side elevation taken from the line 13-13 of Fig. 11.

For the purposes of illustrating the present invention a conventional form of two-cycle internal combustion engine employing a carburetted mixture has been employed. The cylinder structure of this type of engine readily lends itself to the particular relationships by which it may be made by economical die casting operation with the consequent elimination of many machining operations without detracting from desired qualities of rigidity and long life operation.

Referring to Figs. 1 to 6 inclusive an air-cooled single cylinder internal combustion engine is shown comprising a cylinder block 10 which has integral cooling fins 12 projecting from the cylinder wall. An insert or liner 14 of hardened metal constituting the bore of the cylinder may be cast in the cylinder or pressed therein after the casting has been made. The cylinder block 10 has an integral head 16 provided with a threaded opening in which is secured a conventional spark plug. A crankcase 18 is also cast as an integral part of the cylinder block. The crankcase has a piston opening 20 in the bottom thereof of sufficient size to permit the introduction of a piston and the liner 14- in cases when such liner is press fitted into the cylinder after the casting. The crankcase 18 is also provided with oppositely positioned axially alined bearing

cage openings

22 and 24. These openings are large enough in size to permit the longitudinal insertion of a crankshaft into the crankcase and form positive rigid support for the bearing cages and crankshaft bearings.

On one side of the cylinder block there is an exhaust chamber 26 to the face of which is secured an exhaust pipe 28 by bolts 30. Exhaust ports 32 are drilled in the floor of such chamber and liner 14 after the casting operation. In order to introduce fuel intothe combustion chamber from the crankcase 18 an internal fuel transfer passage 34 is provided which extends upwardly within a pad 35 on the other side of the Wall of the cylinder block from the crankcase to an inlet chamber 36. The die for this chamber is removed laterally so that the chamber has a side opening to permit the inlet ports 38 to be drilled in the floor of the chamber and the liner 14 after the casting operation. The chamber is enclosed by a cover 40 held by bolts 42 to the face of such chamber. The die for the transfer passage 34 and the die for the cylinder bore are withdrawn outwardly through the cylinder opening 2i) thus forming the integral head.

When the cylinder block is made by a die casting operation the die for the bore may have the liner 14 fitted thereon so that it will be cast into the wall of the cylinder. In other types of casting operations the liner 14 is pressed into the bore of the cylinder through the piston opening 20. The dies for the exhaust chamber 26 and inlet chamber 36 are withdrawn laterally with the opening of the mold. The casting thus formed may be easily jigged for the honing of the cylinder, the drilling of the ports, the surface boring of the inner wall of the bearing cage openings, and the machining of the faces therearound. The fact that the whole crankcase 18 is integral with the cylinder block makes a rigid construction. Each crankshaft bearing cage is accurately alined and rigidly held in such alinement.

A conventional piston 44 operates in the bore of the cylinder and has secured thereto in the usual manner a connecting rod 46 having a crank bearing with a removable cap 48. This assembly without the bearing cap 48 is first assembled into the block and moved to its uppermost position. A conventional crankshaft 50 having a crank is then put longitudinally through the bearing

cage openings

22 and 24 with the crank in alinement with the crank bearing on the rod 46. By the use of a jig or pusher red the piston and piston rod assembly is moved downwardly so that the crank bearing on the rod will seat on the crank with the crank in lowermost position. In this position the bearing cap 48 may be readily installed and secured by the customary bolts and nuts 52.

A right hand bearing cage 54 having a plain bearing 56 is slid over the right end of the crankshaft 50 and seated in the bearing cage opening 22. A flange 58 rests on the face around such opening 22 and the cage is held to the block by stud bolts and nuts 60 or other like fastening devices. A left hand bearing cage 62 having spaced plain bearings 64- and 66 is slid over the left end of the crankshaft 50 and seated in the opening 24. A flange 63 on such cage rests on the outer face of such opening and the cage is secured to the block by bolts 70 or other like fastening devices. In this particular embodiment the bearing cage 62 has an extending flange 72-. provided with openings by which such flange can be secured to a base for the purpose of mounting the engine.

The piston opening 20, after the assembly of the piston, crankshaft and the bearing cages, is closed by a mounting member 74 which acts as a support for a reed valve '76 and a carburetor.

By reason of the seats on the integral crankcase provided by the bearing cage openings, the bearing cages are accurately alined and rigidly held in place.

In the modification of the invention embodied in the engine illustrated in Figs. 7 and 8 the exhaust and inlet ports are on the same diametrical sides of the cylinder as the crankshaft bearing cage openings. With this arrangement the fuel transfer passage may be formed externally of the cylinder block and enclosed by a cover which is part of the bearing cage. This simplifies the 4- internal die and the removal thereof. In this modification the cylinder block is made by a die cast operation and has the usual cooling fins 112. A cylinder liner 114 may be cast in at the time of casting or pressed in later. The cylinder block has an integral head 116 provided with a threaded opening in which is secured a conventional spark plug. A crankcase 118 is also cast integral with the cylinder block. It has a piston opening 120 in the bottom, a right side bearing cage opening 122, and a left side bearing opening 124. Extending upward from the opening 124 the block has a pad provided with a laterally opening recess forming a fuel transfer passage 134 extending from the upper edge of such cage opening to an inlet chamber 136. The cylinder block also has an exhaust chamber 126 to the face of which an exhaust pipe 128 is secured. Exhaust ports 132 and inlet ports 138 are drilled in the floor of such chambers and the liner 114 after the casting operation. The die for the cylinder bore is withdrawn through the piston opening 120 and the dies for the passage 134, chamber 136, and chamber 126 are withdrawn laterally with the mold.

The engine of this modification also has a conventional piston 144 and assembled piston rod 146 with a crank bearing including a removable cap 143 secured by bolts 152. A crankshaft 150 of standard design is inserted longitudinally into the crankcase 118 through the bearing cage openings 122 and 124. A right side bearing cage 154 with a plain bearing 156 is slid over the right end of the crankshaft and fitted in the bearing cage opening 122. It has a flange 158 seated on the face of such opening and secured to the block by conventional fastening means. A left hand bearing cage 162 having

plain bearings

164 and 166 is slid over the left hand end of the crankshaft 150. It has an annular flange 168 which seats on the outer face of the opening 124 and is secured thereto by bolts 170. This cage also has an upward extension 172 which forms the outer wall for the external fuel transfer passage 134 and the cover for the chamber 136. Bolts 173 are used to hold the extension 172 tightly seated against the outer face of such transfer passage. After assembly of the

cages

154 and 162 and the bearing cap 148 the piston opening 120 is closed by a mounting member 174 which acts as a support for the usual reed valves and a carburetor.

In the modifications of the invention hereinbefore described both crankshaft bearings have been mounted in bearing cages secured as separate elements to the block. It is possible, however, to eliminate one of the bearing cages as a separate element and cast one of the crankshaft bearings integrally with the cylinder block. An engine embodying this feature is illustrated in Figs. 9 and 10. At the time of the casting of the cylinder block 200 the right side shaft bearing support 254 is cast integrally with such block and the usual plain bearing sleeve 256 is pressed into the bore of such support. The left bearing of this modification is held in a cage opening in the crankcase the same as illustrated in either of the two preceding modifications. The crankshaft 250 is inserted longitudinally through the left hand bearing cage opening after the piston and piston rod unit have been assembled. The left hand bearing cage is then inserted over the left end of the shaft 256 and the crank and rod connected. Thereafter the piston opening 220 is covered by a support 274 in the identical manner as previously described.

The modification of the invention embodied in the engine shown in Figs. 11, 12 and 13 illustrates how the cylinder block constructed like the embodiment of Figs. 1 to 6 inclusive may be used in a multi-cylinder engine. Each cylinder block is of identical construction and consequently may be either a right hand or left hand block, that is, the intake side of each cylinder may be placed on the same side, either front (as viewed in Fig. 11) or rear, or one may have the intake side on the front and the other on the rear. A center main bearing cage and bearing are positioned on the center main bearing of the crankshaft and the cylinders are mounted from opposite ends of the crankshaft so as to seat on such center main bearing cage. The cylinders and the outer bearing cages are held in assembled position by through-rods as hereinafter described in detail.

Each cylinder block 318 has cooling fins 312, a cylinder bore with insert 314, an integral head 316, and an integral crankcase 318. The fins on the left side of the right cylinder and the fins on the right side of the left cylinder are cut away at 319 so that the cylinders may be brought close enough to properly engage the center main bearing cage. The crankcase 318 of each cylinder has a piston opening 320 located in the bottom thereof through which the piston and piston rod assembly may be inserted into the cylinder. Each crankcase has a right side bearing cage opening 322 and a left side bearing cage opening 324. Extending radially outwardly from the cylinder block adjacent each of these openings are rod receiving arms 323. An interior fuel transfer passage extends from the crankcase 318 to an inlet chamber 336, such passage being contained in a pad 335 integral with the front wall of each cylinder. Inlet ports 338 leading to the interior of the cylinder are drilled in the floor of the chamber 336 after the casting operation. The inlet cham ber 336 after such drilling is closed by a cover 34!] secured to the cylinder block by bolts 342.

Each cylinder has a conventional piston 344 to which is connected a rod 346 terminating in a crank bearing having a removable cap 348 secured by bolts and nuts 352. A split center main bearing cage 378 is mounted on the center main bearing of a two-crank crankshaft 350. This cage has a peripheral fiange 380 and a bearing sleeve 382. The right hand cylinder block with piston and piston rod assembled is slid over the right end of the crankshaft 250 until the bearing cage 378 fits in opening 324. The left hand cylinder block with piston and piston rod assembled is slid over the left end of the crankshaft 250 until the bearing cage 378 fits in opening 322. The flange 388 is then engaged by the faces of such openings. The center main bearing may be a combination anti-friction bearing and plainthrust bearing like that described and claimed in the application of Ralph N. Kircher, et a1., Serial No. 149,118, entitled Main Bearing for Multi- Crank Engine now Patent No. 2,614,897. It is not essential to this invention, however, that such center main bearing be a combined plain and anti-friction bearing. A plain hearing would be satisfactory provided it forms a pressure seal between the two crankcases.

Instead of employing a single center main bearing cage and bearing, some structural member such as a gear housing may be provided with separate bearing cages and bearings which will receive the ends of separate crankshafts and over which the bearing cage opening 324 of the right hand cylinder block and bearing cage opening 322 of the left hand cylinder block will fit to mount each cylinder.

After the cylinders have been assembled over the outer ends of the crankshaft 350 and positioned on the center main bearing 378 a right hand bearing cage 354 having a bearing sleeve 356 is slid over the right hand end of crankshaft 250 and fitted in the bearing cage opening 322 of the right hand cylinder with its flange 358 resting on the face of such opening. Rod receiving arms 359 project radially from this bearing cage and are alined with the arms 323 on the cylinder block. A left hand bearing cage 362 having a bearing 364 is slid over the left end of the crankshaft 350 and fitted in the bearing cage opening 324 of the left hand cylinder with its flange 368 resting against the face of such opening. This bearing cage also has radially projecting rod receiving arms 369 alined with the arms 323 on such cylinder. With the cylinders and bearing cages assembled as described, through-rods 334 are passed through the projecting arms and secured by nuts 386 to draw the outer bearing cages toward each other clamping the center bearing cage and the cylinders in a rigid position.

By manipulating the crankshaft 350 the cranks may be alternatively brought into position adjacent the piston openings 320 and the piston lowered so that the crank bearings on the rod rest on the cranks and the bearing caps 348 assembled and secured by bolts and nuts 352. When this assembly has been completed for each cylinder the piston openings 320 are closed by mounting members 374 which also act as supports for conventional reed valves and a connection for a carburetor manifold.

Although several embodiments of the invention are shown and described herein, it will be understood that this application is intended to cover such other changes or modifications as come within the spirit of the invention or scope of the following claims:

We claim:

1. In an engine, the combination in a single casting of a cylinder with external radially extending cooling fins and an internal bore, said cylinder having oppositely related inlet and exhaust chambers unobstructedly opening laterally outwardly of said cylinder; a head with external longitudinally extending cooling fins; a crank case having walls and a bottom defining an interior unobstructedly opening downwardly from said cylinder bore and crank case interior, said crank case bottom having an opening large enough to permit the insertoon of a piston into said bore; said cylinder having fuel transfer passage extending from the interior of said crank case to said inlet chamber; said crank case wall having a bearing cage opening large enough to permit a crankshaft to be inserted longitudinally into said crank case.

2. In an engine, the combination as defined in claim 1 in which said cylinder has said fuel transfer passage unobstructedly opening laterally outwardly of said cylinder to define with said inlet chamber, said transfer passage and said bearing cage opening a continuous opening.

3. In an engine, the combination as defined in claim 1 in which said cylinder has said fuel transfer passage unobstructedly opening longitudinally downwardly into said crank case interior and separated by a wall from said bore, said transfer passage being spaced inwardly of the wall of said crank case interior.

4. In an engine, the combination as defined in claim 1 in which said cylinder has a crankshaft bearing opposite said bearing cage opening and coaxially alined therewith.

References Cited in the file of this patent UNITED STATES PATENTS 1,465,165 Hall-Bullock Aug. 14, 1923 2,169,236 Frazier Aug. 15, 1939 2,218,332 Fowler Oct. 15, 1940 2,227,247 Conover Dec. 31, 1940 2,432,725 Connelly Dec. 16, 1947 2,445,715 Jennings July 20, 1948 2,547,327 King Apr. 3, 1951 2,586,467 Jacobsen Feb. 19, 1952 FOREIGN PATENTS 25,771 Sweden Mar. 14, 1906 32,802 Netherlands May 15, 1934